THE
LONDON, EDINBURGH, and DUBLIN

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.
RICHARD PHILLIPS, F.R.S.L.&E. F.G.S. &c.
SIR ROBERT KANE, M.D. M.R.I.A.

" Nee aranearum sane textus ideo melior quia ex se fila gignunt, nee noster
vilior quia ex alienis libamus ui apes. Just. Lips. Polit. lib. i. cap. 1 . Noi.

VOL. XXXV.

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

JULY— DECEMBER, 1849.

LONDON:

RICHARD AND JOHN E, TAYLOR, RED LION COURT, FLEET STREET,

Printers and Publishers to the University of London;

SOI,D BY LONGMAN, BROWN, GREEN, AND LONGMANS ; SIMPKIN, MARSHALL
AND CO.; S. HIGHLEY ; WHITTAKER AND CO.; AND SHERWOOD,

GILBERT, AND PIPER, LONDON : BY ADAM AND CHARLES

BLACK, AND THOMAS CLARK, EDINBURGH; SMITH AND SON,

GLASGOW; HODGES AND SMITH, DUBLIN ; AND

WILEY AND PUTNAM, NEW YORK.

i

" Meditationis est perscrutari occulta ; contemplationis est aclmirari

perspicua Admiratio general quaestionem, quaestio investigationem,

investigatio inventionem." — Hugo de S. Victore.

— " Cur Spirent venti, cur terra dehiscat.
Cur mare turgescat, pelago cur tantus aniaror.
Cur caput obscura Phoebus ferrugine condat,
Quid toties diros cogat flagrare cometas ;
Quid pariat nubes, veniant cur fulmina coelo.
Quo micet igne Iris, superos quis conciat orbes
Tarn vario motu."

J. B. Pinelli ad Manzonium,

CONTENTS OF VOL. XXXV.

(THIRD SERIES.)

NUMBER CCXXXIIL— JULY 1849-

Page

Prof. H. Rose on the Inorganic Constituents of Organic Bodies 1
The Rev, S. Eamshaw on the Transformation of Linear Partial
DiiFerential Equations with constant Coefficients to Funda-
mental Forms 24

The Rev. D. Williams's Cliff Section of Lundy Island, from the

Sugar-Loaf to the Devil's Limekiln 28

Note on the Geological Structure of the Asturias, particularly
in reference to the Nummulitic Eocene, and the Carboniferous
Palaeozoic Rocks of that province (extracted from a letter of
M. E. de Verneuil addressed to Sir Roderick I. Murchison) 34
Mr. C. J. Hargreave's Analytical Researches concerning Num-
bers 36

M. Becquerel on the Development of Electricity in the Act of

Muscular Contraction 53

M. C. Despretz's Note relative to the Electricity developed by

Muscular Contraction 55

M. P. H. Boutigny (d'Evreux) on some facts relative to the
Spheroidal State of Bodies, FireOrdeal, Incombustible Man, &c. 60

Proceedings of the Royal Society * 64

On the Aurora Borealis of February 22, 1849 71

On Liquid Storax and Balsam of Peru, by M. Kopp 72

Identity of Brookite and Arkansite "75

On the Estimation of Molybdic Acid, by M. H. Rose 75

On Glairine, by M. Bonjean 75

On Glairidine, by M. Bonjean 78

On Zoiodine, by M. Bonjean 78

Meteorological Observations for May 1849 79

Meteorological Observations made by Mr. Thompson at the
Garden of the Horticultural Society at Chiswick, near
London ; by Mr. Veall at Boston ; by the Rev. W. Dunbar at
Applegarth Manse, Dumfries - shire ; and by the Rev. C.

Clouston at Sandwick Munse, Orkney 80

. a2

IV CONTENTS OF VOL. XXXV. — THIRD SERIES.

NUMBER CCXXXIV.— AUGUST.

Page
Mr. J. Bryce on the Lignites and Altered Dolomites of the Island

of Bute 81

Prof. J. D. Forbes on an Instrument for measuring the Ex-
tensibility of Elastic Solids 92

Prof. J. D. Forbes on the Refractive and Dispersive Power of

Chloroform 94

Prof, J. D, Forbes on an Experiment to determine the Earth's

Density 95

Mr. E. C. Summers on a Simple Apparatus for Washing Preci-
pitates 96

Dr. Beke on the Sources of the Nile ; being an attempt to

assign the limits of the Basin of that River 98

Mr. W. R. Grove on the Effect of surrounding Media on Vol-
taic Ignition , 114

Dr. Fresenius's Practical application of the Law pointed out by
Dr. R. D. Thomson, of the proper Balance of the Food in

Nutrition 127

Prof. Forbes on the alleged Evidence for a Physical Connexion
between Stars forming Binary or Multiple Groups, arising

from their Proximity alone 132

Sir W. R, Hamilton on Quaternions ; or on a New System of

Imaginaries in Algebra (^continued) 133

Mr. J. Glaisher's Remarks on the Weather during the Quarter

ending June 30, 1849 137

Proceedings of the Royal Society 147

On the Preparation of Pure Oxide of Cobalt, by M. Louyet . . 154

On Aluminate of Cobalt, by M. Louyet 155

Detection of Iodine and Bromine, by M. Alvaro Reynoso .... 156

On the Chemical Nature of the Egg, by M. Barreswil 158

On the Formation of Fatty Matters in Vegetables, by M. Blon-

deau de CaroUes 158

Meteorological Observations for June 1849 159

Table 160

NUMBER CCXXXV.— SEPTExMBER.

Mr. W. R. Birt on the Production of Lightning by Rain .... 161

Prof. De Morgan on Anharmonic Ratio 165

Prof. H. Rose on the Inorganic Constituents of Organic Bodies 171
M. Weber's Examination of the Inorganic Constituents of

Peas and Pea-straw 171

M. Weber's Examination of the Inorganic Constituents of

Rape-seed and Rape-straw 177

M. Struve on the Amount of Silica contained in some Plants 181

CONTENTS or VOL. XXXV. — THIRD SERIES. V

Page

M. Weber's Examination of the Ash of Wheat and Wheat-
straw 1^2

M. Weber's Analysis of the Ash of the Blood of the Ox. ... 185

The Rev. B. Bronwin on the Theory of the Tides 187

Dr. A. Voelcker on the Chemical Composition of the Fluid in

the Ascidia of Nepenthes 192

Sir W. R. Hamilton on Quaternions ; or on a New System of

Imaginaries in Algebra {continued) 200

Dr. Schunck on Colouring Matters 204

Notices respecting New Books : — Dr. Thompson's Introduction

to Meteorology 225 .

Proceedings of the Cambridge Philosophical Society 228

Royal Society 231

Experiments on the Nitrogenous Compounds of the Benzoic

Series, by G. Chancel 236

On the Composition of Stearic Acid, by MM. Laurent and Ger-

hardt '. 237

Meteorological Observations for July 1849 239

Table 240

NUMBER CCXXXVI.— OCTOBER.

The Rev. J. Challis on the Views of the Astronomer Royal
respecting the Modification of Sounds bj'^ Distance of Propa-
gation 241

Mr. B. C. Brodie's Investigation on the Chemical Nature of

Wax 244

The Rev. B. Bronwin on the Theory of the Tides {continued) . . 264
Prof. H. Rose on the Inorganic Constituents of Organic Bodies

{concluded) 271

M. Weber's Examination of the Inorganic Constituents of

the Flesh of the Horse 271

M. Fleitmann's Analysis of the Ashes of Human Faeces

and Urine 273

M. Weidenbusch's Examination of the Inorganic Consti-
tuents of the Bile (of Oxen) 278

M. Weber's Examination of the Inorganic Constituents of

Cow's Milk 279

M. Poleck's Examination of the Inorganic Constituents of

the White and Yolk of Hen's Eggs 281

Mr. B. W. Bull on the Inorganic Constituents of Yeast

(from Berlin Pale Beer) 286

Prof. BufTs Notice respecting Du Bois Reymond's Discovery
of the Development of Electricity by Muscular Contraction 288

M. Matteucci's Observations on the Voltaic Arc 289

Notices respecting New Books : — Mr. John Ainslie's Treatise
on Land Surveying 293

VI CONTENTS OF VOL. XXXV. — THIRD SERIES.

Page

Proceedings of the Royal Astronomical Society 294

On Carbonate of Lime as an Ingredient of Sea- Water, by Walter

White, Esq 308

Gold in certain Mines of the Department of the Rhone, by MM.

Allain and Bartenbach 309

On the Analysis of Plants by Incineration, by M. Caillat .... 309

Blue Arseniate of Copper, by M. RebouUeau 310

On Methylamine and Ethylamine, by M. Adolphe Wurtz .... 311
On Valeramine or Valeric Ammonia, by M. Adolphe Wurtz . 313

On Chloroform, by MM. Soubeiran and Mialhe 314

On the Preparation of Nitrogen Gas, by M. B, Corenwinder. . 317
On the Quantity of Ammonia contained in Atmospheric Air, by

M. R. Fresenius 318

Meteorological Observations for August 1849 319

■ Table 320

NUMBER CCXXXVIL— NOVEMBER.

Mr. E. J, Chapman on the Notation of Crystals 321

Mr. W. Crum on a peculiar Fibre of Cotton which is incapable

of being Dyed 334

The Rev. B. Bronwin on the Theory of the Tides (^concluded). . 338
Dr. Gladstone on the Compounds of the Halogens with Phos-
phorus 345

Sir J. W. Lubbock on Shooting Stars 356

Mr. J. Glaisher's Remarks on the Weather during the Quarter

ending September 30, 1849 357

Mr. Claudet's Researches on the Theory of the principal Phse-

nomena of Photography in the Daguerreotype Process .... 374

Proceedings of the Royal Astronomical Society 386

Cambridge Philosophical Society 392

Rain, the Cause of Lightning, by T. H. Dickson 392

On a Compound of Sulphurous Acid and Water, by M, Dcepping 393
On the Methods of ascertaining the quantity of Bromine in so-
lution in Mother- Waters, by M. Fehling 394

Detection of small quantities of Iodine, by M. L. Thorel .... 395
Contributions to the Chemistry of the Metals of Platina, by M.

C. Claus 396

On the Composition of Honey, by M, Soubeiran 398

Meteorological Observations for September 1849 399

Table 400

NUMBER CCXXXVIII.— DECEMBER.

Dr. Pring's Observations and Experiments on the Noctiluca mi-
liaris, the Animalcular source of the Phosphorescence of the

CONTENTS OF VOL. XXXV. — THIRD SERIES. Vll

Page
British Seas ; together with a few general remarks on the
phsenomena of Vital Phosphorescence 401

Prof. De la Rive on the Vibratory Movements which Magnetic
and Non-magnetic Bodies experience under the influence of
external and transmitted Electric Currents 422

Mr. J. Cockle on Systems of Algebra involving more than one
Imaginary ; and on Equations of the Fifth Degree 434

Mr. E. J. Lowe on a remarkable Solar Phsenomenon seen at
the Villa, Beeston near Nottingham, October 22. 1849. ... 437

M. G. Bontemps's Inquiries on some modifications in the Co-
louring of Glass by Metallic Oxides 439

M. A. De la Rive on the Cause of Aurorae Boreales, being an
Extract from a Letter to M. Regnault 446

Prof. B. Silliman's Descriptions and Analyses of several Ame-
rican Minerals 450

I. Species of the Family Mica 450

II. On Unionite 457

III. On Monrolite 458

IV. On the identity of Sillimanite,Fibrolite and Bucholzite

with Kyanite 459

V. On the Boltonite of Shepard, and Thomson's Bisilicate

of Magnesia 462

VI. On Nuttallite 464

On the State in which Arsenic exists in the Deposit from Mi-
neral Waters, by M. J. L. Lassaigne 465

Easy Mode of measuring Solar Objects, by W. Pringle 467

Natural Sources and new Mode of preparing Sulphuric Acid, by

M. C. Blondeau 467

Notes on the California Gold Region, by the Rev. C. S. Lyman 470
Combinations of Oil of Turpentine and Water, by M. H. Deville 474
Action of Phosphoric Acid on the Hydrates of Oil of Turpen-
tine, by M. H. Deville 477

On the Influence of Boracic Acid on Vitrification 478

Meteorological Observations for October 1849 479

Table 480

NUMBER CCXXXIX.— SUPPLEMENT TO VOL. XXXV.

MM. E. de la Provostaye and P. Desainson the Rotation of the

Plane of Polarization of Heat by Magnetism 481

Prof. B. Silliman on a Granular Albite associated with Corun-
dum, and on the Indianite of Bournon 484

Mr. S. M. Drach's Supplementary Considerations to his Epicy-

clical Papers (Phil. Mag. June to July 1849) 487

Mr. R. Phillips on Electricity and Steam 490

Mr. T. S. Davies on Geometry and Geometers. No. IV 497

Mr. S. Beswick's Illustrations of a Method for computing Mag-
netic Declination, on the principle proposed by Prof. Gauss 511

VIU CONTENTS OF VOL. XXXV. THIRD SERIES.

Page

Proceedings of the Royal Astronomical Society 519

Institution of Civil Engineers 526

Royal Society 528

On the passage of Hydrogen Gas through Solid Bodies, by M.

Louyet 545

Qualitative and Quantitative determination of Phosphoric Acid,

by M. Leconte 545

Index 546

THE

LONDON, EDINBURGH and DUBLIN

PHILOSOPHICAL MAGAZINE

AND

JOURNAL OF SCIENCE.

[THIRD SERIES.]

JULY 1849.

I. 0)1 the Ijio7'gafiic Constituetits of Organic Bodies, By
H . Rose, Professor of Chemistry in the University of Berlin ^.

THE inorganic constituents of vegetable and animal sub-
stances have received more attention during the last few
years than was formerly the case ; and in consequence of
Liebig's exertions especially, numerous investigations of the
ashes of organic substances have been made; but their prin-
cipal object was only technical. It was soon perceived, that
as plants derive the inorganic constituents, without which
they cannot exist, from the soil, it was of the greatest import-
ance to determine these constituents with accuracy, so as to
be enabled to judge whether the soil was capable of yielding
them ; and if not so, to allow of their being added in the form
of a suitable manure.

Hitherto almost all these investigations have been directed
to the determination of the relative proportions of the inorganic
constituents of the ash. Occasionally, indeed, the presence
of certain inorganic constituents, especially salts, has been •
detected by microscopic examinations; but scarcely any one
has expressly taken up the question which is somewhat closely
connected with this point, viz. in what manner are the inor-
ganic substances combined with the organic? Whether they
form with each other the same kinds of combinations as those
which are artificially prepared in our laboratories, or whether
peculiar compounds, existing only in living organic bodies,
are formed by the mutual influence of the inorganic upon the
organic matters, are questions which must be of great import-
ance, especially in animal and vegetable physiology, and which
have not hitherto been accurately investigated.

In very few instances only have researches of this kind
been attempted. Endeavours have been made, for instance,
* From Poggendorff's Annalen, vol. Ixxvi. p. 305.

Phil. Mag, S. 3. Vol. 35. No. 233. July 1849. B

2 Prof. H. Rose on the Inorganic Constituetits

to show the manner in which the iron is combined with the
other constituents of the blood. But these and some other ex-
periments of the same kind form isolated examples ; at least it
has never been attempted to ascertain the changes which the
inorganic constituents supplied to vegetable and animal bodies
by the soil and articles of food undergo within them.

Some time since, I endeavoured to prove, that when an
organic substance of vegetable or animal origin is carbonized
with exclusion of the air, by not too great a heat, the inorganic
constituents can partly be extracted by the ordinary solvents
of inorganic salts — water and muriatic acid, but that a portion,
and this frequently the largest, exists in the carbonized residue
of some organic substances in such a state as completely to
resist the solvent action of water and muriatic acid, and can
only be obtained by burning the carbonized mass in oxygen
gas or in atmospheric air*. This portion of the inorganic
matters undoubtedly does not exist in the organic substance
in the state in which it is obtained after the incineration, nor
even in the carbonized mass obtained from it, but it has been
formed by oxidation. I also described several experiments,
which showed that the presence and the nature of the car-
bonized mass could not be the causes of the insolubility of the
inorganic substances in the solvents, even if they pre-existed in
the organic bodies in the same state as that in which we find
them in the ash.

These remarks, which I published in an imperfect state
and supported by few proofs, for the sake of directing the
attention of chemists to this, as it appeared to me, not unim-
portant subject, have not received any attention. Since that
time, I have, however, occupied myself with these investiga-
tions, and have induced several young chemists in my labora-
tory to determine the inorganic constituents, with a view to
separating those which exist already formed in organic bodies
from those which must be contained in them in an unoxidized
or less oxidized state.

These investigations have completely confirmed the view I
had arrived at from reflecting upon this subject. In fact I
may assert, that in none of my chemical investigations has
experiment so completely confirmed the hypotheses which I
had made before the commencement of the undertaking than
in these.

When we minutely trace the entire process by which plants
and animals assimilate the inorganic substances consumed, it
appears that this is effected in the two cases in an entirely op-
posite manner. I shall now investigate this more minutely,
* Chem. Gaz., vol. v, p. 158.

of Organic Bodies. 3

The Inorganic Constituents of Plants.

Plants obtain their inorganic constituents by means of the
roots, which derive them from the soil upon which they grow.
The latter either already contains them among its constituents,
or they are added to it in a suitable manure. In both cases
these inorganic constituents exist in the highest possible state
of oxidation. If they are not contained in the manure in this
state, the latter is not in a perfectly proper condition, and does
not become so until it has been exposed to the air for some
time.

It may certainly be admitted, that the inorganic constituents,
absorbed by the root in the most perfect state of solution pos-
sible, ascend in the vessels of the stem. Probably those salts
which are insoluble in water are dissolved by the aid of car-
bonic acid.

During the growth of the plant a deoxidizing process goes
on within it ; the green parts under the influence of solar light,
as is well known, evolve oxygen gas. Even when they only
decompose the carbonic acid of the air, they assimilate its
carbon ; hence the amount of the latter in the plant gradually
increases in proportion to that of the oxygen. All those parts
of the plant which are in contact with the green parts take a
share in this deoxidizing process, so long as it continues in a
state of growth and the green parts have not lost their green
colour. Now when we find that in plants one portion of the in-
organic constituents absorbed by the root exists in a deoxidized
state, in which, at least after the carbonization of the plant, it
is insoluble in the ordinary solvents — water and muriatic acid,
and that this portion is not converted into the same salts as
those absorbed by the root from the soil until after oxidation,
it may be supposed that the quantity of deoxidized inorganic
constituents must be small in those parts of the plant which
are in more immediate contact with the soil, and in which,
therefore, the deoxidation of the parts of the plant, and also
that of the inorganic salts existing in them, first commenced.
But this quantity must be greater in those parts of the plant
the formation of which has required the longest time ; and
after the formation of which, many plants, including all the
annuals, die. Hence the proportion of the inorganic consti-
tuents of the plants which are deoxidized to that of those which
are not deoxidized, must be very different in the herbaceous
portions of the plant and the seeds.

This supposition has been most completely verified by ex-
periment.

M. Weber made a comparative experiment upon the inor-

B2

Prof. H. Rose on the Inorganic Constituents

to'

ganic constituents of peas and pea-straw, which is more fully
described in the appended supplement (I. and II.). They
were both carbonized, with exclusion of the air, at such a
temperature, that the water with which the carbonized mass
was treated was not coloured yellow or brown, but re-
mained perfectly colourless. Water extracted from the car-
bonized mass of the peas a large amount of chloride of po-
tassium and phosphate of potash, some chloride of sodium and
sulphate of potash, and a considerable quantity of carbonate
of potash : the latter must have been contained in the peas,
before carbonization, in the form of the potash-salt of an
organic acid. Water extracted from the carbonized mass of
the pea-straw a far larger amount of carbonate of potash, but
smaller quantities of chloride of potassium, chloride of sodium,
sulphate of potash, silicate of potash, and sulphate of lime.

When the carbonized mass, which had been exhausted
■with water, was then treated with muriatic acid, the latter
dissolved out of the carbonized peas phosphate of soda, pot-
ash, lime, magnesia, and perphosphate of iron, but no earthy
carbonates; whilst from the carbonized pea-straw this acid
extracted a large quantity of carbonate of lime, a small quan-
tity of carbonate of magnesia, and the phosphates of lime,
magnesia and iron, but none of potash or soda.

The carbonized mass which had been exhausted with water
and muriatic acid was burnt with access of air. The ash of
the peas consisted of the phosphates of potash, lime, mag-
nesia and iron ; that of the pea-straw was composed of the
phosphates of magnesia, lime and iron; it contained no pot-
ash, but a considerable quantity of silica.

On comparing the amounts of inorganic matters obtained
from the peas and the pea-straw by these two operations, the
following results are obtained. 100 grms. of peas and 100
grms. of pea-straw yielded —

Peas. Pea-straw.

Exhausted by water 0*380 r417grm.

Exhausted by muriatic acid . . . 0*356 3*4<58 grms.
On the incineration of the car-"] « ^«« r.a^,-

bonizedmass J 0*909 0*375 grm.

Hence water and muriatic acid dissolved very considerable
quantities of inorganic constituents from the carbonized pea-
straw, but not more than a sixth or seventh of this amount
from the peas; whilst on the incineration of the carbonized
mass which had been exhausted by solvents, far more fixed
salts were formed in the case of the peas than in that of the
pea-straw.

The proportion in the latter case is, however, far more

of Organic Bodies. 5

remarkable than is at first sight apparent ; for the ash of the
exhausted carbonized mass of the pea-straw contains more
than half its weight of silica, which existed as such in the oxi-
dized state in the living plant, and could not be obtained until
after the incineration of the carbonized mass, merely in con-
sequence of its insolubility in the solvents. If we take this
circumstance into account, the exhausted carbonized mass of
the peas yields five times as large an amount of fixed salts
as that of the pea-straw.

Exactly the same results were obtained in the analysis of
the inorganic constituents of rape and rape-straw, made by
M. Weber (Appendix III. and IV.).

The quantities per cent, of inorganic constituents were —

Rape. Rape-straw.

Extracted by water 0'230 1*556

Extracted by muriatic acid . . . 0*884 1*805
On the incineration of the car-1 , „„. „ -^„

1 00* \J Ol\J

bonized mass

'-}

Here also the proportion is more striking than appears at
first sight, because nearly half of the ash of the carbonized
mass of the rape-straw after exhaustion with the solvents, con-
sists of silica, as in the case of the pea-straw.

The salts obtained by the incineration of the carbonized
mass after exhaustion by the solvents, could not have existed
as such in the plants and seeds, as has been already men-
tioned, nor even in the carbonized mass itself, but must have
been produced by oxidation. The next question then is, in
what states of combination did the unoxidized inorganic con-
stituents exist in the plant, and what in the carbonized mass
obtained from it? Upon this point all our explanations are
insufficient ; and this question can only be answered by hypo-
thesis, which cannot be verified without further investiga-
tions. But at all events the subject forms a wide field for
interesting investigations, which lead to important results, and
by which both chemistry and physiology may acquire im-
portant elucidation.

The carbonized residue of peas and rape, after exhaustion
with water and muriatic acid, yields on incineration a large
amount of phosphates, and which, had they existed as such in
the carbonized vegetable matter, would have been dissolved
by the water and muriatic acid. The carbonized mass also
contains considerable quantities of nitrogen. If the phosphorus
existed in the unoxidized state, it is most probable that it
formed compound radicals with carbon and nitrogen, similar
to cyanogen or sulphocyanogen, which were combined with the

6 Prof. H. Rose on the Inorganic Constituents

metals of the basic oxides contained in the ash. Hence in
proportion as the deoxidizing process proceeds in the living
plant, the phosphates which are absorbed from the soil by the
roots become converted into non-oxidized compounds, consist-
ing of compound radicals containing phosphorus and the me-
tals of the alkalies and earth. These must exist in the largest
quantity in those parts of the plants which are composed of
substances exposed for the greatest length of time to the de-
oxidizing process ; and these are evidently the seeds of the
plants, which are formed latest, and upon the production of
which the life of many plants entirely ceases.

Thus the phosphates are decomposed in plants by the de-
oxidizing process in the same manner as the sulphates are
converted into sulphurets by deoxidation. Probably the
more appropriate explanation is, that when substances con-
taining nitrogen and carbon are present, sulphocyanurets, or
compounds of a radical consisting of three elements, sulphur,
carbon and nitrogen, may be formed from the sulphates by a
deoxidizing process.

If we admit the occurrence of these compounds of hypo-
thetical radicals with metals in the seeds of plants, the next
point, after the determination of their properties, would be the
investigation of their relation to the great mass of the organic
matter in those parts of the plants in which they exist. But
as even the existence of these compounds is problematical, it
would be useless to form further hypotheses on this point
before making ourselves somewhat more intimately acquainted
with these compounds themselves.

The so-called proteine compounds appear to be formed
principally in plants by the process of deoxidation ; and it is
precisely these substances which appear to combine with the
radicals containing phosphorus, in combination with metals.

Another question must be proposed here, although it cannot
be satisfactorily answered. Supposing that these compounds
really exist in certain parts of plants, what changes do they
undergo when the plant is carbonized with exclusion of air;
when consequently all the organic matter is destroyed, and the
connexion in which they probably stood to these compounds is
dissolved ? So long as we have no certain knowledge of the
existence of these compounds, we cannot judge with certainty
of the changes which they experience at an elevated tempera-
ture. It is however possible, at least not improbable, that
they may be acted upon at an elevated but not too high a
temperature in the same manner as the cyanurets, when
they are transformed by heat into paracyanurets. Be
this as it may, the experiments show that these compounds

of Organic Bodies, 7

after carbonization are insoluble both in water and in muriatic
acid. But this insolubility in the solvents did not always
exist before carbonization; for many organic substances, which
in an undecomposed and not carbonized state are soluble in
water, frequently contain a large part of their inorganic con-
stituents in an unoxidized state.

It is well known, that most of, but not all, those inorganic
salts which are insoluble in water are soluble in muriatic acid.
But those salts which are insoluble in this acid certainly very
rarely occur in vegetable and animal substances. The meta-
phosphates require most attention in this respect, since they
may exist in the carbonized substance ; and yet, on account
of their insolubility in water and muriatic acid, their presence
may only be detected after the destruction of the carbonized
mass. But it is evident, from the investigations which have
been made upon the inorganic constituents of vegetable and
animal substances, and which are described in the Appendix,
that these metaphosphates can rarely if ever be present, since
in most cases carbonate of potash may be removed from the
carbonized mass by water, and which, as is well known, can-
not exist simultaneously with metaphosphates at an elevated
temperature.

We must next mention the remarkable occurrence of silica
in vegetables, principally in the stems of the Grasses and Equi-
setacece (Appendix V.). The silica is undoubtedly removed
from the soil by the plants in the form of silicate. It becomes
separated, however, from this silicate ; and the silica separated
forms the principal mass of the stem in several species o{ Equi-
setum and the Grasses. Of course it exists in them in the form
of perfectly oxidized silicic acid ; but in consequence of its in-
solubility in water and muriatic acid, the greater part of it is
found in the mass remaining after the exhaustion of the car-
bonized substance with water and acid.

Hence on comparing the quantities of the inorganic sub-
stances which the seeds and the culm of grasses yield in the
aqueous and muriatic solutions of the carbonized substance,
and on the combustion of the latter, we find, in contradiction
to the above deteraiination, that the carbonized straw yields
far more fixed substances than the seeds. But this contradic-
tion is only apparent, because the substances obtained after
the incineration of the carbonized straw consist almost entirely
of silicic acid.

A comparative examination of the inorganic constituents of
wheat and wheat-straw made by M. Weber, and which is fully
described in the Appendix (VI. and VII.), proves this beyond
a doubt.

8 Prof. H. Rose on the Inorganic Constitueiits

Water extracted chloride of sodium and phosphate of pot-
ash and soda from the carbonized grains of wheat, but no
carbonates ; whilst from the carbonized wheat-straw it removed
chloride of potassium, chloride of sodium, some sulphate of
potash, and no phosphates, but a remarkably large amount of
silica. Muriatic acid subsequently dissolved only compounds
of phosphoric acid with potash, soda, lime, magnesia and per-
oxide of iron. From the carbonized straw, muriatic acid ex-
tracted combinations of phosphoric acid with lime, magnesia
and peroxide of iron, as also some silica.

The carbonized grains of wheat, after exhaustion by the
solvents, yielded on combustion, compounds of phosphoric acid
with potash, lime, magnesia and peroxide of iron ; also some
silica. The solids remaining after the combustion of the car-
bonized wheat-straw consisted almost entirely of silica, with
extremely small quantities of the phosphates of lime, magnesia
and peroxide of iron.

On comparing the amounts of the constituents obtained in
the different operations, we obtain the following results. 100
grms. of the grains of wheat and of the straw yielded —

Grains of wheat. Wheat-straw.

In the aqueous solution . . . 0*471 grm, l'216grm.

In the muriatic solution ... 0*562 .,, 0*474 ...

On the incineration of the car-"l « „ . ^ o ^ « ,-

u ' A r 0*246 ... 2*135 ...

bonized mass .... J

Of the 2*135 grms. of fixed constituents which the carbon-
ized wheat-straw yielded, 2*022 grms. consisted of silica, and
only 0*113 grm. of phosphates. When this is taken into
consideration, this investigation also proves that the quantity
of so-called deoxidized inorganic constituents in the grains of
wheat is greater than that in the wheat-straw.

Perhaps it is of importance to distinguish the organic sub-
stances, the inorganic constituents of which are contained in
them in a completely oxidized or deoxidized state, by separate
names.

I shall therefore call those organic substances, the inorganic
constituents of which are in a perfectly oxidized state, teleoxidic
bodies. Pea-straw and rape-straw, as also even wheat-straw,
may be called teleoxidic substances, although they do not
deserve this appellation so strictly as many animal bodies, ©f
which we shall speak presently. But those organic substances,
the inorganic constituents of which exist partly in an oxidized
and partly in an unoxidized state, I shall call meroxidic sub-

of Organic Bodies. 9

stances. Peas, rape and wheat, are therefore meroxidic sub-
stances. I have never met with perfectly anoxidic substances^

either in the examination of vejjetable or animal substances.

1 • • •
It is probable that if the proteine compounds existing m me-
roxidic substances were isolated as completely as possible,
they would constitute perfectly anoxidic substances, which
after carbonization would not yield any soluble salts to the
solvents, until these had been produced by complete incine-
ration.

Inorganic Constituents of Animals.

Animals derive the inorganic constituents which the various
parts of their body contain, from the food. This is, however,
assimilated by them in a totally different manner to that in
plants; whilst in the latter, in general, a process of deoxida-
tion occurs, to which the inorganic substances derived from
the soil are subjected, in animals the nutritive substances
undergo oxidation by the oxygen inspired. They are first
converted into blood, and this is conveyed to all parts of the
body, where reparation must occur. By the oxidation of the
nutritive substances, or rather of the matters produced from
them, the elevated temperature of the animal body is produced;
and as this is tolerably uniform, the oxidation also must go
on equally uniform in the various parts of the body. It is
not, however, merely those parts of the body which consist of
carbon, hydrogen, nitrogen and oxygen only, that take part
in the oxidation, but undoubtedly also those compounds of
the hypothetical phosphuretted radicals with metals, which
such animals as are not carnivorous derive from the meroxidic
substances of vegetable nutritive matters. That portion of
them which is not applied to the repair of the body becomes
oxidized ; the same also occurs with those parts of the body
which are repaired. Whilst the carbonic acid of these com-
pounds is expired in the form of carbonic acid, and the nitrogen
is converted into ammonia, the phosphorus is oxidized to form
phosphoric acid, and the metals combined with the radicals,
so as to form oxides. The longer these substances have been
exposed to oxidation, the more perfectly are phosphates of the
metallic oxides formed.

It must follow from this conclusion, that the matter first
formed by the nutritive substances, the blood, from which the
other parts of the body are repaired, may contain completely
oxidized salts, since it is generated from meroxidic substances,
but must still contain a large amount of the combinations of
the hypothetical radicals with metals. Somewhat the same
must occur with flesh, the composition of which is the same

10 Prof. H. Rose on the Inorganic Constituents

as that of the blood ; but as it is formed from the blood, it
must contain more oxidized inorganic salts and less deoxidized
salts than the blood. But if oxidation still continues, the
inorganic constituents, which become perfectly oxidized by
the inspired oxygen, must finally be removed from the body,
as they are of no further use in it. Thus we find, in fact, that
the inorganic constituents of the fluid and solid excrementitious
matters are in a perfectly oxidized state, and are perfectly
teleoxidic substances. Experiments upon the inorganic con-
stituents of the blood, flesh, and the excrements, have com-
pletely confirmed these suppositions.

The inorganic constituents of the blood of the ox have been
examined by MM. Weber and Merk (Appendix VIII.).

In the blood which was used for this purpose, the clot cer-
tainly had coagulated from the liquor sanguinis ; but they were
both carbonized without separation.

Water extracted from the carbonized mass a very large
amount of chloride of sodium, carbonate of potash and of soda,
and mere traces of phosphate and sulphate of potash.

Muriatic acid removed from it an inconsiderable amount of
the phosphates of soda, potash, lime, magnesia, and perphos-
phate of iron.

The carbonized mass after exhaustion with these solvents
yielded, on incineration, the phosphates of soda, potash, lime,
and magnesia, with a large quantity of peroxide of iron and a
small quantity of silica; it also contained traces of sulphates.

The following are the relative amounts of the inorganic
constituents obtained by the three operations : —

In the aqueous solution 3*920 grms.

In the muriatic solution 0*389 ...

On the incineration of the remainder of\ o-iou

the carbonized mass j

We thus see that the amount of oxidized salts in the blood
is very large. They consist, however, for the most part of
salts soluble in water; and of these chloride of sodium, which
cannot be considered as an oxidized salt, is the principal con-
stituent, forming more than half of the whole amount of these
salts. When this is taken into consideration, the quantity of
inorganic constituents formed by the incineration of the car-
bonaceous mass after exhaustion with the solvents is larger
than that of the salts contained in the blood. Hence the
blood is a meroxidic body.

Flesh (that of the horse) has been examined as to its inor-
ganic constituents by M. Weber (Appendix IX.).

Water extracted from the carbonized flesh small quantities

of Organic Bodies. 1 1

only of metallic chlorides, and oF sulphate of potash, a large
quantity of alkaline phosphates, but no alkaline carbonate.

Muriatic acid then dissolved a considerable quantity of
phosphates from the mass.

The residual carbonaceous mass yielded an ash which also
consisted of phosphates.

The following were the relative amounts of inorganic con-
stituents obtained in the analysis : —

In the aqueous solution 3*090 grms.

In the muriatic solution 1*262

On the incineration of the carbonized mass 2*866 ...

Hence flesh, like blood, is a meroxidic substance. The
latter apparently contains a comparatively larger amount of
teleoxidic matter than flesh. But the aqueous solution of the
carbonized blood contains nearly 60 per cent, of chloride of
sodium, whilst that of the carbonized flesh contained only very
small quantities of alkaline chlorides. On taking this into
consideration, the quantity of anoxidic matter in the blood is
larger than in the flesh, and that of the teleoxidic matter
smaller in the blood than in flesh.

The inorganic constituents of the liquid and solid excre-
mentitious substances have been determined by M. Fleitmann
(Appendix X. and XL).

The extraordinarily large amount of salts contained in the
urine is well known : they exist in it in a perfectly oxidized
state. On evaporating the urine and carbonizing the dry
residue, with exclusion of the air, water extracts almost the
whole of the salts. On treating the carbonized mass, after
exhaustion with water, with muriatic acid, a somewhat con-
siderable amount of phosphates is further dissolved, part of
which had been separated by the evaporation of the urine.

The carbonized mass remaining after the action of water
and muriatic acid, yielded so small a quantity of ash on com*-
bustion, as to give rise to the supposition that the inorganic
constituents obtained in this way had also existed in an oxi-
dized state in the urine, and had merely escaped the action of
the solvents in exhausting the carbonized mass. One of the
principal constituents of these inorganic substances was silica,
which must have been separated on the evaporation of the
urine and heating the dry residue, and have thus become
insoluble in muriatic acid. The urine may therefore be con-
sidered as one of the perfectly teleoxidic substances.

The quantities of the inorganic constituents obtained in
these operations were as follows : —

12 ProfI H. Rose on the Inorganic Constitiients

In the aqueous solution 54*148 grms.

In the muriatic solution 5'085

On the incineration of the carbonized mass 0*352

From the carbonized faeces water extracted some chloride
of sodium and potassium, a considerable quantity of carbonate
and phosphate of potash, a less amount of sulphate of potash,
and a very large quantity of free potash.

But the quantity of inorganic constituents dissolved by mu-
riatic acid was very large. It consisted of much phosphate of
lime and magnesia, phosphate of potash and soda, a very small
amount of sulphate, silicate of potash, and a very small quan-
tity of peroxide of iron.

The exhausted carbonized mass on incineration yielded no
very inconsiderable quantities of fixed constituents, the prin-
cipal of which, however, was silica in the form of sand {san-
dartige Kieselsdicre). It moreover contained a tolerably large
amount of lime and magnesia, with a small quantity of phos-
phate of potash and soda, peroxide of iron and silica.

The relative quantities in the different solutions and in the
remaining carbonized mass were as follows : —

In the aqueous solution 1*933 grms.

In the muriatic solution 6*493 ...

On incineration of the carbonized mass 1*996 ...

But on deducting from the latter amount that of the silica and
sand, we only obtain somewhat more than 1 grm., and hence
the solid excrements may be considered as belonging to the
teleoxidic substances.

Whilst those inorganic oxidized constituents which are
soluble in water are separated by the urine, those which are
insoluble pass off as faeces. In proportion as digestion in the
body goes on in a normal state, and the less the excess of
nutritive substances introduced into it, the amount of im-
perfectly oxidized constituents of the faeces must be less,
and the quantity of teleoxidic substances larger. It is
therefore probable that, by the chemical investigation of the
faeces, a conclusion may be formed as to the proper or defective
manner in which digestion is carried on. The fact that the
inorganic constituents of the liquid and solid excrements,
especially the phosphates, exist in them in the oxidized state,
is the principal reason of their use as manure, which must
be more fit for this purpose in proportion to the amount of
teleoxidic substances of which it consists.

As the inorganic substances from animal bodies are added
to plants in the form of manure, the process, in which they
are first deoxidized and then again oxidized, recommences.

of Organic Bodies. 13

The examination of other parts of the animal body by the
method described is of some interest. As regards the boneSi
it is well known that all their inorganic constituents may be
extracted by dilute muriatic acid, so that the cartilage remains
in a pure state : likewise when they have been heated to redness
with exclusion of the air, muriatic acid dissolves the inorganic
salts, and leaves pure carbon. We know that bone-black, as
it is called, may be decomposed in this manner.

Thus the bones, like the liquid and solid excrementitious
matters, contain the larger amount of their inorganic salts in
a perfectly oxidized state, and entirely belong to the teleoxidic
substances. This explains the fact that ground bones form
one of the best manures.

The bile (ox-bile) has been examined by M. Weidenbusch
in the same way (Appendix XII.). Likewise, in this case, the
surprising result has been arrived at, that the inorganic con-
stituents, as in the excrements, exist almost wholly in the oxi-
dized state, and that the bile is therefore a teleoxidic substance.

By far the larger portion of the inorganic constituents of
the carbonized mass of the bile is extracted by water. It dis-
solves principally the carbonate, phosphate, and sulphate of
soda, with chloride of sodium; the quantity of salts of potash
dissolved is, however, very small.

Muriatic acid extracted from it a small quantity of phos-
phate and a trace of silicate. The bases were principally
lime, soda, potash, magnesia and the protoxides of iron and
manganese.

The washed residue yielded a very small quantity of ash on
incineration, which contained a remarkably large amount of
sulphuric acid, and but little phosphates. The bases were
principally soda, potash, magnesia and lime.

The following are the quantities of the inorganic constituents
which were obtained in the various operations : —

In the aqueous solution 16*01 8 grms.

In the muriatic solution 0*869

On the incineration of the carbonized residue O'V-i^S ...

It is thus evident that the inorganic constituents of the bile
exist in an almost complete state of oxidation, precisely as in
the urine.

The next question is whether the milk is also an excretion,
like the urine, and whether the whole of its inorganic consti-
tuents exist in a perfectly oxidized state. It appears, how-
ever, from M.Weber's experiments upon the milk of the cow,
that in addition to numerous perfectly oxidized salts, it also
contains a considerable amount of inorganic constituents in a

14 Prof. H. Rose on the Inorganic Constituents

deoxidized state, and is therefore a meroxidic substance (Ap-
pendix XIII.).

The aqueous extract of the evaporated and carbonized milk
contains a large amount of alkaline chlorides, with phosphate
and carbonate of potash.

The muriatic extract of the carbonized mass contains a
large amount of phosphate of lime, with small quantities of the
phosphates of magnesia, potash and soda.

On the incineration of the exhausted carbonized mass,
further large quantities of the phosphates of lime, potash, soda
and magnesia were obtained.

The following are the relative proportions of the inorganic
constituents obtained in the various operations : —

In the aqueous solution 7*125 grms.

In the muriatic solution 6*621

On the incineration of the remainder of\ ^ . „„
the carbonized mass j

Thus the milk contains a considerable amount of both
oxidized and unoxidized inorganic constituents. It cannot
under any circumstances be arranged in the same class as the
urine, and like the latter, be considered as an excretion. It is a
meroxidic compound.

In eggs (hens' eggs) the inorganic constituents are in a more
oxidized state in the albumen, whilst they are in a more un-
oxidized state in the yolk, as appears from the experiments of
M. Poleck (Appendix XIV. and XV.). These experiments,
however, were made long ago in n)y laboratory; the methods
adopted were consequently imperfect, and they recjuire repe-
tition. This is the more necessary, since the results of these
experiments appear to be in opposition to those which have
been obtained in almost all the others. For all those meroxidic
substances which have been examined, such as peas, rape-seed
and wheat, moreover the blood, flesh and the milk, contain a
large amount of the so-called proteine compounds. In tele-
oxidic substances, the excrements and the bile, the proteine
compounds are entirely absent; and in the straw of peas, rape
and wheat, they exist in small quantity only, corresponding to
the amount of meroxidic substances found in them. It is pro-
bable therefore that the proteine compounds, when freed as
perfectly as possible from all the teleoxidic substances which
accompany them, are in many cases perfectly anoxidic sub-
stances. The only results opposed to this view, are those ob-
tained by M. Poleck, as regards the albumen of eggs, which
contains a small quantity of anoxidic substances.

of Organic Bodies. 15

Method of examining the Inorganic Constituents of Oiganic
Substances.

Vegetable substances are first freed as completely as possible
from all foreign admixtures ; solid animal matters are exposed
to a gentle heat, to remove the greater part of the water
they contain; and animal liquids are to be evaporated to
dryness at a gentle heat. In this state the substances are
placed in a Hessian crucible, the lid of which is furnished with
a hole in the middle, the joints between the lid and the crucible
are carefully luted with clay, and the crucible then placed for a
long time in a hot place, and, if possible, all the remaining mois-
ture expelled. It is then exposed to a moderately strong heat
in a wind-furnace in a charcoal fire; the gases which escape
through the hole are inflamed, and when the flame has burnt
out and no more gases are evolved, the hole is closed with an
accurate stopper of chalk, the crucible heated at a very low
red heat, and then allowed to cool with perfect exclusion of
the air.

The examination of the carbonized mass resolves itself into
three parts.

Part I. — The carbonized mass is first powdered as finely as
possible, then boiled for a long time with water in a platinum
dish, filtered and washed with hot water until a few drops of the
filtering liquid leave a slight residue only, when evaporated
upon platinum-foil. It is scarcely possible to continue washing
the mass until the liquid which runs through leaves no residue,
because a little phosphate of lime is always dissolved. It is
therefore best, when the residue obtained on evaporating the
water used in washing is very slight, to test a few drops ot the
water which runs through with solution of nitrate of silver ;
if a slight opacity only is produced, which disappears on the
addition of nitric acid, this arises from phosphate of lime in
solution, and we may be certain that all those constituents
which are soluble in water have been removed. If the tur-
bidity does not disappear on the addition of nitric acid, this
arises from the water used in washing still containing some
chlorides, and the washing must be continued longer.

On boiling the carbonized organic substances with water,
as also on evaporating the aqueous extract, I have never been
able to detect the evolution of ammonia. Hence, during the
carbonization, neither alkaline cyanides nor alkaline cyanates
are formed.

In all those substances which have hitherto been examined,
the aqueous solution contained chlorides. If the amount pre-
sent is small, the carbonized mass is easily washed ; but if they

16 Prof. H. Rose on the Inorganic Constituents

form a principal constituent, the carbonized mass frequently
requires to be washed for several weeks.

It sometimes happens that the aqueous solution appears of
a brownish colour, which depends upon the imperfectcarboniza-
tion of the substance. Usually the liquid becomes decolor-
ized on concentration, and deposits woolly flakes of carbon,
which may be easily separated by filtration, before other sub-
stances are deposited from it.

If alkaline carbonates exist in the aqueous solution in any
considerable quantity, free alkali is formed by the action of the
carbon upon the alkaline carbonate, with the evolution of car-
bonic oxide. If the aqueous solution be evaporated, the dry
mass contains more or less hydrated alkali with alkaline car-
bonate. By means of a solution of nitrate of silver, we may
readily convince ourselves of the decomposition of the car-
bonic acid in the alkaline carbonates by carbon, since, unless
the mixture has been exposed to a very great heat, this re-
agent does not produce a pure white precipitate in the filtered
aqueous solution, but a more or less brownish precipitate is
formed, which contains oxide of silver as well as the white
carbonate of silver.

Decomposition of the alkaline carbonates ensues principally
when the organic substance during its carbonization evolves
a very large quantity of olefiant gas. Hence it takes place to
a great extent when such seeds as contain a large amount of a
fatty oil are carbonized, as rape-seed ; it occurs to a much less
extent on the carbonization of other seeds which do not con-
tain any remarkable quantity of fatty oil, as peas, and likewise
with the herbaceous parts of plants.

Unfortunately my attention was not directed to this circum-
stance until all the experiments described in the Appendix
were entirely or partly finished. The alkali among the con-
stituents of the aqueous extract is therefore assumed as exist-
ing in the state of hydrate.

It is therefore advisable to pass a current of carbonic acid
gas through the aqueous solution before evaporating it, so as
to convert the hydrated alkali into the state of alkaline car-
bonate.

The aqueous solution is then evaporated to dryness in a
platinum capsule. It usually happens that when the liquid
is very concentrated, it becomes more or less turbid from
the separation of phosphate of lime which was in solution.
When the liquid has been evaporated to a small volume,
the phosphate of lime which has separated may be removed by
filtration ; it is however difficult to free the aqueous solution
from it perfectly in this way ; in fact in some cases it cannot

nf Organic Bodies. 17

be done, especially when it contains a large amount of silica,
which also separates on the concentration of the liquid. It is
therefore best to evaporate the whole of the liquid to dryness,
and to separate the phosphate of lime in the course of the ana-
lysis.

The residue is moderately heated until its weight remains
constant. If it be heated too strongly, decomposition of the
carbonates contained in it may readily occur, as when silica
and phosphates are present carbonic acid is expelled, which
in fact partly occurs, according to Heintz*, during evapora-
tion. After determining the weight of the dry residue of the
aqueous solution, it is analysed as follows : —

The quantity of carbonic acid is first estimated by means of
pure nitric acid in a suitable apparatus. This is obtained by
the loss in weight of the apparatus. If, during this operation,
the silica has become separated in the acid liquid, it is removed
by filtration, and the chlorine precipitated from the filtered
liquid by solution of nitrate of silver. The excess of silver is
removed from the liquid after the separation of the chloride
of silver by muriatic acid, andit is then evaporated to dryness in
a porcelain capsule. The dry residue is moistened with mu-
riatic acid and treated with water. Some silica usually re-
mains undissolved, which, when added to that previously ob-
tained, gives the whole amount contained in the aqueous
solution.

The liquid separated from the silica is treated with ammo-
nia, by which the entire amount which has been taken up by
the water is precipitated. It is filtered, washed, dried, heated
to redness, and weighed. Its weight, when deducted from
that of the residue after evaporation to dryness, yields the
true weight of the aqueous extract. It is mixed with the car-
bonized mass which has been exhausted by water.

The liquid is then treated with oxalic acid. In very ^evf
cases only is a precipitate of oxalate of lime thrown down, in
most cases it is not so. The oxalate of lime is determined as
carbonate by the ordinary method.

The filtered liquid is then treated with a solution of chloride
of barium. The precipitate consists of phosphate, sulphate
and oxalate of baiyta. It is filtered and washed. Although
the oxalate of baryta is not very difficultly soluble, yet after a
little practice we can readily judge when the washing must be
discontinued. It is therefore advisable, on precipitating the
lime, not to add too large a quantity of oxalic acid, so as to
avoid obtaining a too copious precipitate of oxalate of baryta.

The precipitate is treated with dilute muriatic acid ; sulphate
* PoggendorfTs Jnnalen, vol. Ixxii. p. 120.
Phil. Mag. S. 3. Vol. 35. No. 233. July 1 849. C

IS Prof. H. Rose on the Inorganic Constituents

of baryta is then left undissolved, and its weight must be de-
termined after it has been washed. We thus estimate the
amount of sulphuric acid. The muriatic solution of the
barytic salt is treated with sulphuric acid, and the precipitated
sulphate of baryta separated by filtration. It is then super-
saturated with ammonia and muriate of ammonia, and sul-
phate of magnesia added to precipitate the phosphoric acid.
Its weight is calculated from the phosphate of magnesia, after
having been heated to redness.

The liquid from which the insoluble barytic salts have been
separated by chloride of barium, still remains to be examined.
The excess of chloride of barium is decomposed by carbonate
of ammonia. If the liquid is very dilute, it must be previously
concentrated by evaporation. The carbonate of baryta is
separated by filtration, the filtered liquid evaporated to dry-
ness, and the dry residue carefully heated to redness to expel
the ammoniacal salts. The remaining mass consists entirely of
alkaline chlorides. These are separated in the ordinary way
by chloride of platinum. The amount of potash is determined
from the weight of the ammonio-chloride of platinum. The
amount of chloride of sodium may be calculated from the loss;
but it is better to determine it directly as sulphate of soda.

Part II. — This part of the investigation is commenced by
boiling the carbonized mass, which has been exhausted by
water, with muriatic acid for a long time ; it is then filtered and
washed with hot water, to which a little muriatic acid has been
added, until a few drops of the water used in washing leave no
residue when evaporated upon platinum foil. Thefiltered liquid
is evaporated nearly to dryness in a platinum capsule. The
weight of the dry residue cannot be determined, on account
of the readiness with which the chlorides of iron and magne-
sium are decomposed by heat. The alkalies usually existed
in the dry residue as chlorides, whilst they were contained in
the exhausted carbonized mass in the form of phosphates; for
when the carbonized mass has been washed with water, and a
portion of the latter is treated with nitric acid, no precipitate
is produced in this solution by solution of nitrate of silver. In
arranging the constituents of the muriatic solution, their sum
must be taken, and the alkalies represented in the state of
oxides.

I was at first much astonished at finding alkalies present in
the muriatic solution, as I had no reason to believe they existed
in it. Subsecjuent investigations, however, which I shall de-
scribe in a future paper, have shown that when pyrophosphate
of lime and pyrophosphate of magnesia are heatetl with not too
large a proportion of alkaline carbonates, remarkable double

of Organic Bodies. 19

suits, consisting of the earthy phosphates in combination with
the alkalies, are formed. Most of them are analogous in com-
position to the ammonio-phosphate of magnesia, but contain
a fixed alkali instead of ammonia. The extremely imperfect
decomposition which ensues on fusing the phosphates of lime
and magnesia with alkaline carbonates, depends in most cases
upon the formation of these double salts.

Their formation is undoubtedly the cause of the quantities
of the alkalies being estimated incorrectly, and in too small
proportion, in many investigations on the determination of the
inorganic constituents of organic substances, because their
presence in the muriatic solution could not have been expected.

The mass obtained by evaporation is moistened with muriatic
acid and then treated with water. Usually a small quantity
of silica remains undissolved, which is separated by filtration
and its weight determined. The liquid is then neutralized
with ammonia. The precipitate contains phosphoric acid in
combination with lime, magnesia and peroxide of iron. It is
well known that when phosphate of magnesia has been heated
to redness, and is then dissolved in an acid, it cannot be com-
pletely precipitated by ammonia : the error, however, arising
from this source is of only slight importance; because the
carbonized mass has been heated for a very long time with
muriatic acid, by which means, as is well known, the pyro-
phosphate of magnesia is almost entirely converted into the
c-phosphate of magnesia. The extremely small quantity of
magnesia which remains in solution is, however, determined
in the further progress of the analysis.

The phosphates which have been precipitated by the am-
monia are dissolved in nitric acid, and treated with mercury
to separate the phosphoric acid from the bases. The dried
mass is treated with water, and the mercurial salt removed
from the solution by muriate of ammonia and ammonia; the
lime is then precipitated by an alkaline oxalate, and the mag-
nesia by phosphate of soda. Wherv peroxide of iron is mixed
with the earths, it is separated by the usual methods. The
insoluble mercurial residue containing phosphoric acid is fused
with carbonate of soda, and the fused mass treated with water.
Should any peroxide of iron then remain undissolved, it is
separated by filtration, dissolved in muriatic acid, and preci-
pitated by ammonia. The liquid which has been separated
from the peroxide of iron by filtration, and which contains
phosphate and carbonate of soda, is supersaturated with
muriatic acid and then with ammonia, and the phosphoric
acid precipitated by sulphate of magnesia. The amount of
phosj)horic acid is calculated from the weight of the ani-

C2

20 Prof. H. Rose on the Inorganic Constituenls

nionio-pliosphate of magnesia after it has been heated to red-
ness.

By the analysis of the phosphates precipitated by ammonia,
the composition of the precipitated phosphate of lime and the
presence or absence of the perphosphate or pure peroxide of
iron in the precipitate may be determined. The liquid filtered
from the earthy phosphates contains either alkalies and phos-
phoric acid only, as is the case in the examination of allseeds
and animal matters, or it contains lime and magnesia only,
and these frequently in very considerable quantities. They
existed in the carbonized mass in the form of carbonates ; but
it is only in those cases in which they are present in consider-
able quantities, as in the analyses of the straw of peas and rape,
that a very distinct evolution of carbonic acid can be per-
ceived on treating the carbonized mass, after exhaustion with
water, with muriatic acid. As the carbonic acid cannot be
determined directly, it is calculated from the quantity of lime
and magnesia found in the liquid filtered from the earthy
phosphates.

In the analysis of the carbonized mass of vegetable seeds
and animal substances, where, as has been previously men-
tioned, the liquid filtered from the earthy phosphates contains
both alkalies and phosphoric acid, this is treated with chloride
of barium; phosphate and, when sulphuric acid is present,
sulphate of baryta are then precipitated. Sulphuric acid has,
however, very rarely been found in the muriatic extract of the
carbonized mass. The phosphate of baryta is separated by
filtration, dissolved in muriatic acid, the baryta precipitated
from the solution by sulphuric acid, which is then supersatu-
rated with ammonia, and the phosphoric acid precipitated as
ammonio-phosphate of magnesia.

The liquid which was separated from the phosphate of
baryta contains the alkalies. The excess of baryta is removed
by carbonate of ammonia, the filtered solution evaporated to
dryness, and the dry mass heated to redness to expel the am-
moniacal salts. The alkaline chlorides left are separated by
chloride of platinum.

The examination of the second portion can be considerably
simplified when sulphuric acid is absent. The muriatic extract
is carefully evaporated. If it contains silica, the dry mass is
moistened with nitric acid, and the silica separated ; mercury
and nitric acid are added to the filtered liquid ; it is then eva-
porated to dryness with excess of mercury in the ordinary
way, and the bases separated from the phosphoric acid by
water.

This simplified method has, however, two disadvantages.

of Organic Bodies. 21

The large amount of chlorine present produces a large quan-
tity of protochloride of mercury, which remains mixed with
the protophosphate of mercury ; hence this insoluble mixture
requires a large quantity of carbonate of soda for its decom-
position. The second disadvantage is, that when the earths
form the principal constituents of the acid extract, it cannot
be accurately determined whether they are combined with
phosphoric or carbonic acid.

Part III. — This part of the investigation comprises the de-
termination of the inorganic constituents existing in the car-
bonized mass after exhaustion with water and muriatic acid, or
rather which are produced by oxidation.

This incineration of the carbonaceous mass is accompanied
by no small difficulties. 1 formerly effected it by heating it to
redness in a crucible, the lid of which was perforated, and a
silver tube, which conducted a current of oxygen to the heated
mass, was fitted to the aperture. The incineration succeeded
perfectly in this manner; but in a very large number of cases
it was impossible to incinerate the carbonized mass merely by
the access of atmospheric air without the aid of oxygen. But
on combustion in oxygen gas, an elevated temperature is pro-
duced and the substance of the crucible is powerfully attacked
by the phosphates formed by the oxidation. If a platinum
crucible be used, it is completely spoiled when alkaline phos-
phates and carbon act upon it at an elevated tempera-
ture. Nor can a porcelain crucible be used ; because when
the greater portion of the carbon has been burnt, the alkaline
phosphates, being in a state of fusion, dissolve the glaze. This
is particularly the case with porcelain crucibles of Meissen
manufacture ; but even those manufactured at Berlin cannot
resist the action, although they are far less acted upon than
the former. Silver crucibles do not stand the high tempera-
ture, and begin to melt. When the combustion of the car-
bonized mass is effected in a glass tube heated to redness in a
furnace by a charcoal fire, it succeeds tolerably well ; but the
high temperature produced by the combustion of the carbon
in oxygen fuses the alkaline phosphates, and they unite with
the glass, so that they cannot afterwards be separated from it
mechanically. The combustion was finally effected in small
earthenware crucibles, which answered in every respect tole-
rably well, and were but slightly acted upon by the alkaline
phosphates; but one important difficulty still remained un-
conquered, — a considerable quantity of alkaline phosphate
is constantly volatilized. This is very large; and the vola-
tilization cannot in any way be avoided when the combus-
tion is effected in oxygen gas, even when the current is slo\y.

22 Prof. H. Rose on the Inorganic Constituents

When the gas was })assed through too slowly, combustion diil
not take place; but as soon as it was allowed to flow. more
quickly, t!ie oxidation of the carbon occurred with the pro-
duction of a vivid light, and white fumes were distinctly seen
to ascend. For the purpose of examining the volatilized pro-
ducts, the combustion of the carbonized mass was effected in
a tubulated glass retort, through the tubulure of which the
oxygen was passed, whilst its mouth was inm)ersed in water.
The water was found to exhibit powerful reactions of phos-
phoric acid and alkali.

If a mixture of alkaline phosphate with a large proportion
of carbon is artificially prepared, and the mixture burnt in a
current of oxygen, the same phsenomena as those just described
are found to occur, and dense white fumes are seen to ascend.

This volatilization only occurs with alkaline phosphates.
On the combustion of a carbonized substance, which after in-
cineration yields earthy phosphates only, volatilization cannot
be perceived. Moreover, when earthy phosphates are artifi-
cially mixed with carbon, and the mixture burnt in oxygen
gas, volatilization does not occur, nor can any white fume be
perceived. Hence the earlier experiments which were per-
formed in my laboratory, in which the washed carbonized
mass was burnt in oxygen gas, have yielded incorrect results,
and must therefore be repeated, as a method has at last
fortunately been discovered by which the combustion can be
effected without loss. This method, which was proposed by
M. Fleitmann, is as follows : —

The carbonaceous mass, after having been exhausted with
water and muriatic acid, is dried, and then moistened with a
concentrated solution of chloride of platinum. The moist
mass is heated in a porcelain crucible or a porcelain capsule,
at first gently, so that no moisture may be expelled and no loss
occasioned by the spirting of the mass ; then more strongly,
so that it attains an incipient red heat. This is best effected
in a large concave lid ot a platinum crucible. If the whole be
heated in a porcelain crucible, the incineration requires a far
longer time, inasmuch as it takes place more slowly in pro-
portion to the smallness of the surface and the less free con-
tact of the air. A very slow combustion of the carbon ensues,
chlorine being simultaneously developed ; each carbonaceous
particle becomes incandescent, just as in the scintillation of an
inflamed vegetable substance. The combustion is extraordi-
narily increased by constantly stirring the mass with a plati-
num wire or a small platinum spatula. As fresh portions of
the unburnt carbon come into contact with the air, the scin-
tillation recommences. The spirit-lamp may be removed,

of Organic Bodies. 23

yet the carbon continues to glow for a long time; frequently,
when the quantities are not too small, for several hours ; even
portions taken out with the platinum spatula continue to burn.
The more concentrated the solution of platinum is, the more
readily does the combustion ensue. When the mass ceases
to glow on the continued application of heat, and still appears
black, it must be again moistened with chloride of platinum.
The less carbon the residue contains, the more readily does
the combustion ensue. If the solution of platinum is concen-
trated, twice moistening and heating are usually sufficient to
produce the combustion of the whole of the carbon. A second
moistening with the solution of platinum is not strictly requi-
site. After the mass has been once moistened and then heated
to redness, the residue may be treated with aqua regia and
evaporated, so as to render the platinum again active; how-
ever, this is a somewhat tedious proceeding; great care
must also be taken that no loss is occasioned by the spirting
of the mass. As the whole of the platinum used is usually
recovered, the method does not entail any pecuniary loss; it
is therefore preferable to moisten the mass a second time with
chloride of platinum.

When all the carbon has been burnt, the residuary mass is
of a pure ash-gray colour. Before it is treated with muriatic
acid, it must be heated to redness in a porcelain crucible in a
current of hydrogen gas, so that the double compounds of the
alkaline chlorides with the chloride of platinum may be com-
pletely decomposed, which can onl}' be accomplished with
difficulty with large quantities by merely heating them in atmo-
spheric air. If the treatment with hydrogen gas be omitted,
the subsequent separation of the platinum from the muriatic
solution of the ash is accompanied with several inconveniences.
The mass, after having been treated with hydrogen gas, is df-
gested for a long time v^ith muriatic acid in a flask, the residue
separated by filtration, and washed with water containing mu-
riatic acid. The resulting solution, which usually contains
the same constituents as the muriatic extract of the carbon-
ized mass, is analysed in exactly the same manner.

The platinum remaining undissolved, which is also mixed
with the sand and silica of the organic substance, may be sepa-
rated from these substances by two methods. The whole is
either boiled in a platinum capsule with a solution of carbonate
of soda, which dissolves the silica, leaving the platinum and
the sand, which may then be separated by aqua regia ; or the
mass is treated at once with aqna regia, when the sand ana
silica remain undissolved, and may be separated from each
other by boiling with a solution of carbonate of soda. The

24 The Rev. S. Earnshaw on the Transformation

silica dissolved in the solution of carbonate of soda is obtained
by supersaturating the solution with muriatic acid, evaporating
to dryness, and treating the residue with water; the silica
then remains undissolved.

A solution of caustic potash cannot be used for separating
the silica from the sand in the analyses of the ashes of vege-
table substances, but carbonate of soda must be made use of
for this purpose; for the sand is not in most cases pure sand,
but usually consists of a mixture of sand and clay, which is
either derived from the soil upon which the plants grew, or
from the floor of the barn upon which the corn was thrashed,
and which has been driven into the straw and the grains of
seed during the process of thrashing. This clay is readily
decomposed by a solution of caustic potash, the alumina being
dissolved, and the amount of silica contained in the substance
is rendered incorrect by the silica dissolved out of the clay.
When carbonate of soda is used, this decomposition of the
clay does not occur.

[To be continued.]

II. On the Transformation of Linear Partial Differential
Equations with constant Coefficients to Fundamental Forms.
By the Rev. S. Earnshaw, M.A.*

THERE are to be met with in books occasional instances
of the transformation of equations of the class here pro-
posed to be considered, but I am not aware that the subject
has ever been entered upon systematically. A iesiv years ago,
when engaged in some speculations on Laplace's equation, I
effected the transformation of all partial differential equations,
with constant coefficients, of the second order, for two and
three independent variables. The method seems applicable
to higher orders and any number of variables. The result of
my investigations is, that every partial differential equation of
the second order, with constant coefficients, can be transformed
into one or other of these two forms, when there are two in-
dependent variables,

— -

dxdy ~ ^ ''

d^u du

d^^^'^Ty' <^-)

and into one or other of these two forms, when there are three
independent variables,

♦ Communicated by the Author.

of Linear Partial Differential Equations. 25

d^u (Pu du ,,.

dxdi/ dz^ d.
d'^u du

= a

(4.)

dxdi/ dz

the value of a being either zero or unity.

I have not been able to discover that these are capable of
further simplification ; for which reason in the title of this
communication I have called them fundamental forms. If you
think this subject worthy of a place in your Journal, 1 will, in
a future communication, add to it a few remarks on the inte-
gration of the equations here considered.

1. To transform

d^u ^ J d^u p d'^u .,du , y>/^" , ]^ _^
daf-^ "^ </?/^ dxdit/ dx dy '

the general partial differential equation of the second order
with constant coefficients.

Changing the variables by means of the assumptions

we have

+ (2a + 2hg^ + C .gTI) ^ -f (A' + B'^0 %

Now as g and ^ are arbitrary, subject only to the condition
of being unequal, we may assume them to be the roots of
a-|-C^-|-ig2=0, unless C^ = 4a6. By this assumption the
first and second terms of the last equation will disappear, and
therefore the equation will be reduced to the form

^ d^u ..du r„du ^ , ^ .

0=^0^-^ +A'-^ +B'-j- -\~Du. . . (5.)
dxdy dx dy

Let us transform this equation by assuming u—ve^'''^'"^; by
this means it becomes

4(C/w + A7+B'm + D)T;;

and as I and m are arbitrary it is always allowable to assume
C7W + A' = 0, C/+B=^0, by which it is reduced to the form

„ dhi ,^
0 = C-j— J- -f D?<;
dxdy

26 The Rev. S. Earnshaw on the Transformation

and this by writii)g a'a;^ —Uy for .r and y ; and assuming
C« = fl'Z;'D, takes the form (1.); to which, therefore, the general
equation proposed can always be reduced when C^ is not

2. But when C^ = 4-ai, then as we cannot make the above
assumptions for^ and g', we may suppose ^ = 0, and a + Cg'
4-^a'2=0; it will then be found that the third term of the first
transformed equation in art. (1.) will vanish of itself, and thus
the transformed equation is of the form

If we proceed with this as with (5.) it becomes

and as /, m are arbitrary, we can always make the second and
last terms of this to disappear ; by which means it takes the
form

d^u „, du

which may be further reduced, as before, to the form (2.).

3. To transform

d^u J d^u d'^u . d^u ^ d^u p d'^u . , du
dx^ dy'^ dz^ dydz dxdz dxdy dx

„, du ^, du „
+ B'^+C'^ +Dm=0,

the general partial differential equation of the second order
with three independent variables.
Change the variables by the assumptions

^ = x+gy, ri=x+g'y, ^=x-^hy^kz.

This gives

0=^a^bg^+Cg)^ +{a + bg^^ + Cg')^ +{a + bm + ck^

+ AA^ + B^ + C^) ^ + (2a + Cy + 2^?+C.//+ A^^+B./f )

|^ + (2« + Cg+26^TC.A+A^B.^)0^

d^u , . , ^, ^ du

+ (2a + C.g+5'4-2^'gg')^P^- +(A' + B'^)^^
+ (A'+B'^')^' +(A' + B'/% + C'/t)^' +D«.

of Linear Partial Differential Equations. 27

Now as g and g' are arbitrary, subject only to the condition
of being unequal, and hk are also arbitrary, subject only to
the condition that k must not be zero; if C"^ be not equal to
4<ai, we may assume gg' to be the roots of a-\-Cg-\-bg^^=0,
and hk such as to make the 4th and 5th terms of the above
equation vanish. By this method the reduced equation takes
the form

This equation we may now further transform by writing
^g'x+my+nz p^,. ^^. \^y which meuus we obtain

+ {2nc + C) ^ + {cn^ + Cmn + A' I + Bhn + C'n + D)v.

Now as /,?w, w are absolutely arbitrary, we can always so assume
them as to make the 3rd, ^th, and 6th terms of this equation
vanish. The reduced equation then takes the form

dz* ax til/ dz

which may be further reduced, as before, to the form (3.).

4. But if C'^=4a6, we cannot then assume^ and ^ to be
the roots of the equation a-\-Qg-\-hg^=.Q ; let us therefore in
this case assume ^^ = 0, and g' such thato'H- C^' + 6^'^ = 0 ; and
hk as before: it will be found that by this means the 2nd, 4th,
.'jth and 6th terms of the first transformed equation in art. (3.)
vanish, which therefore takes the form

d'^u d^u .,du „, du „, du -^ / , v

"""S^+^S^+^'s+^rf^+C'j^+D^. . (8)

This equation we may now further reduce by the same method
as was employed in reducing (7.)s and it thus becomes

d^v d% ,^ , ... dv ,-,, dv ,^ „,, dv

+ (a/2 + cn^ + A7 + B'm + C'w + D) v.
Now as /, OT, n are absolutely arbitrary, we may assign such
values to them as to make the 3rd, 5th, and 6th terms of this
equation disappear; which being done, it takes the form
dhi d^u r>tdu
dx-^ dz^ dy

But if we change the variables of this equation by writing
^■=.x-\-fz.t J^ — x+J'z, it becomes

« / . /-9X <^'^ /^ ^ ,v/^ d'^u , rio.d'^n rt.du

28 The Rev. D. Williams's Cliff Section of Lundy Island.

in which we are at liberty to suppose^/' to be the roots of
a + c/'^=0, which reduces it to the form

_„ d'^u T), ^M

~ dxdz dj/

which may be further reduced, as before, to the form (4.).

Thus it has been proved that (1.), (2.), (3.)j (4-) are the fun-
damental forms of partial differential equations of the second
order with constant coefficients, for two and three variables.
If there be more variables, it is evident the method here em-
ployed will still apply, and enable us to reduce them to fun-
damental forms. I have not had occasion however to pursue
the method beyond what is here done; nor have I applied it
to equations of the third and higher orders, though I am in-
clined to think that with some modification it would enable us
to reduce them to fundamental forms.
Sheffield, May 18, 1849.

III. Cliff Section of Lundy Island, from the Sugar-Loaf to the
DeviPs Limekiln. By the Rev. D. Williams*.

THE specimens to which the following descriptions refer,
were collected and numbered on the spot, and occupy,
as near as may be, the relative positions assigned them on the
section.

No. 1. Granite, often of the porphyritic variety, a ternary
compound of mica, quartz, and felspar only.

2. Gray granite, differing only from the former by the ac-
cession of rare and remote specks and crystals of foliated
hornblende, which apparently replace the mica to the amount
only of such accession.

3. Gray granite, more syenitic, of a greenish tint, not so
distinctly crystalline granular as the last, at times calcareous,
and the mica in a greater degree absent.

4. Gray granite, with a less shade of green, no hornblende,
slightly calcareous, mica none or scarcely perceptible, the
quartz crystalline granular, and the felspar in well-defined
and confusedly crystalline arrangement.

5. Gray, compact, or finefy granular granite rock, with no
trace of hornblende, the mica absent or extremely minute and
scarcely distinguishable, but otherwise compounded of felspar,
quartz, carbonate of lime, and calcareous spar ; the two latter
in such augmented proportions, as to cause the rock to effer-
vesce briskly or feebly at nearly all points on being tested by
acids.

* Communicated by the Author; being the substance of a memoir
communicated to the British Association, &c. held at Swansea in 1848.

The Rev. D. Williams's Cliff Section of Lundtj Island. 29

30 The Rev. D. Williams's Cliff Section of Lundy Island.

6. Dark olive-gray hornblende porphyry, passing into a
black bottle green colour with disseminated crystals of cal-
careous spar, at times remote, at others so thickly grouped
together as almost to usurp the base, and nearly to touch each
other.

7. Light and olive-gray compounds of clay, felspar, quartz
and lime, parted out in inch-thick layers and lesser lamina-
tions of schist by delicately thin plates of fibrous calcareous
spar, passing into a calcareous trappean foliated marl, and
marl rock, sometimes more thickly laminated and without the
calcareous spar partitions, at others a clay schist. At the foot
of the section on the N.N.E., where 6 and 7 is as if wedged
in, and curves out in No. 5 *, a conglomerate of fine gravel in
a base of felspathic schist or greenish-gray volcanic ash, per-
taining rather to No. 5 than to 6 or 7, is distinctly seen.

8. Black, finely granular crystalline hornblende trap, feebly
calcareous, rendered somewhat porphyritic by crystals of glassy
felspar, so nearly black as only to be detected by the light
reflected from their cleavaged facets; it also contains sparely,
a green mineral like olivine, more irequently iron pyrites, at
times white on exposure; and commonly small white spherules
of calcareous spar.

9. Unctuous clay schist, evidencing no alteration from its
contact with No. 8, differing little or nothing in composition
and texture from much of No. 7.

10. Flinty, talcose clay, and felspathic schists and slates,
in indefinite alternations.

11. Buff and ochreous rusty-coloured porphyry.

N.B. The unshaded parts represent a lofty cavity at either
extremity, caused by the more ready decomposition of the
calcareous products.

It is a notable fact, that after the confines of the slate and
granite at Lundy, a distance of half a mile, we have not a
vestige of a granite vein ; the same intermediate substances,
Nos. 6, 7 and 8, are met with at either extremity, and at in-
tervals between them, and the immediately bounding schist
and slate show no amount of alteration, or so little, that re-
garding those intervening substances, and their mineral rela-
tions with, and transition into, the granite, the inference that
the schists had metamorphosed the granite or the original
granite lava, is far more probable and defensible than an in-
verse supposition.

From Nos. 1 to 10 inclusive, we had so many graduated

* This remarkable feature in the section is at nearly the base of the cliff,
and is sometimes quite obscured by shingle, which shifts theie very much
at times.

The Rev. D. Williams's CliffSection of Lundy Island. SI

stages of mineral variaiion, between the extreme terms of
typical granite passing b}' calcareous granite, syenite, black
compact hornblende trap, greenstone porphyry, and greenstone
ash or mud, into clay schist and crystalline slate (the proxi-
mate eflfecls of a great physical constant), linked together in
such a ehiiin of mutual relations and dependences as demon-
strated their codimon source and origin.

The author had met with the same connected mineral series
in every ancient volcanic group of Devon and Cornwall, from
the focal granite lava to the finely levigated and impalpable
mud, oftentimes in more full and circumstantial particulars
than were detailed at Lundy Island ; but, on the other hand,
the daily washed and unambiguously disclosed sea-clifF sec-
tio)is of the latter, satisfactorily explained to his mind the in-
tervaled but reiterated occurrence of those enormous masses
of hypersthene and greenstone on the flanks and immediate
confines of the several granite domes, and which often ap-
peared to pass by syenite into the granite, but whose relations
to it otherwise were concealed. Wherever he had met with
those masses of greenstone, &c., he had never met with granite
veins penetrating the bounding rocks, whereas they were uni-
formly more or less present in the intervals of their occur-
rence. There, as at Lundy, the bounding sedimentary rocks
in the one case showed little or no amount of alteration, in
the other they were changed to a vast amount and extent, and
exhibited all the varying phases or stages of reduction, from
perfect fusion to semifusion and incipient induration.

The remarkable proportions of lime in certain of the Lundy
series, constituting, as it did in some of the terms, far beyond
a moiety of the component ingredients, gave undeniable proof
of the occasional presence of lime in granite and its cognate
thermogenous rocks ; so that lime is not invariably so defi-
cient a substance in this class of mineral compounds as had
commonly been supposed; while the instances he adduced
naturally suggested the inquiry, why such deficiency should
exist in the majority of cases.

He regarded it as an altogether fabulous assumption, and
a necessary corollary of the day-dream ot the solar, or fire-
niist origin of granite, that at any period of the earth's history,
lime should have been in a less proportion than it bears at
present to the other elementary earths. Such fabulous origin
o( granite, combined with the supposed absence of lime in it,
suificiently explains the contrary supposition which has Ijecn
advanced ; while the sequel hypothesis, which attributes the
present amount of lime in nature to the polyparia and mol
lusca, — in other words, that creatures whose existence at all

32 The Rev, D. Williams's Cliff Section of Lundy Islatid.

depends upon a pre-provision of lime in the medium in which
they are destined to live, should originally have created it out
of nothing, very admirably sustains the unities of the fiction.

He had learned in Devon and Cornwall, that the several
granite bosses there, pertained to and were inseparably con-
nected with certain well-defined divisions, of what he termed
the Ocrynian group. Those granites he regarded severally
as so many ancient submarine volcanic centres, consecutively
generated, and raised to their present positions by " elevation
crater movements," each one standing out now in lofty and
august relief above its mineral relations and dependences, the
tor-crowned type and head of its own volcanic department.

Those inseparable associates and dependences on granite,
were syenites, porphyries, hypersthenes, serpentines, green-
stones, greenstone ash and tuff, clay schists, crystalline slates,
and co}-al built and chemically precipitated limestones.

In every instance the author had met with, all the lime-
stones and calcareous rocks which had been invaded and acted
on by the vein-like processes of fusion, or by active heat, had
lost either the larger proportion or the whole of their lime ;
in other words, the lime and carbonic acid had been driven
off by heat.

Bearing on this fact, the vast masses of travertine which have
been precipitated from water in subaerial volcanic districts,
must have been at the expense of some other rocks or pro-
ducts, from which it had been abstracted by it, a result no
doubt of the eager affinities which are known to subsist be-
tween lime and water.

These simple and familiar principles he considered quite
adequate to explain the relative absence or low per-centage
of lime in granite, and in its many metamorphosed and dis-
guised relations, taking them as submarine volcanic products.
The lime, driven off by the reduction of calcareous rocks, or
availing itself of the freedom it acquired in the condition of
fluid lava, would readily part from its less attractive associates
to unite with an element of more powerful affinities, which
would serve as its vehicle of translation beyond the cincture
or radius of the deadly volcanic emanations and their "azoic
and protozoic " deposits, to remoter and more genial regions,
where it would minister to the requirements of multiplying
myriads of coral architects and other zoo])hytous, molluscous,
crustacean, and vertebrate creatures, which out of that con-
stant provision and supply of materials would in time con-
struct rock masses of such corresponding scale and dimensions,
as to contribute to and subserve the more final purpose of ter-
restrial restoration or repair.

The Rev. D. Williams's Cliff Section of Lundy Island. S3

Another irresistible induction presented itself in the Lundy
series. The most fiistidious mineralogist, if he admitted gra-
nite to be a physical substance, and not a metaphysical abs-
traction, must concede that the specimen No. 2 on the sec-
tion, was granite modified by a very trifling accession of horn-
blende. But this necessary admission will conduct him by a
series of insensible gradations to the inevitable conclusion,
that the calcareous dark green porphyry and the black horn-
blende trap or greenstone are nothing else than granites in
disguise, or granitic matter masked in colour and modified in
substance, by the accession of varying proportions of horn-
blende and lime, and no doubt other adventitious minerals.

The cabalistic traditions of cosmogony which leaven the
whole lump of geology at the present hour, and which rigor-
ously excluded a particle of hornblende and lime from granite,
nevertheless included (no doubt from their universal associa-
tion) slate and schist in the category of granite and the primi-
tive formations. Yet what geologist, he asked, in the present
day, would venture to talk of primitive or primary slate and
schist?

If these slates and schists, then, were demonstrably neither
azoic, protozoic, primitial, primitive or primary — if, in truth,
they were of all dates, from the most ancient to the newer
pliocene, the granites and their congeners were the same.
There was a negative fact, too, which (in the universality of
its negation, accompanied, as it was, by such an accumulation
of probable and circumstantial testimony as amounted to
the best positive evidence,) led to the same conclusion. If
granite were a primary and independent substance, a sort oi
mineralogical fact but a metaphysical abstraction, as the cos-
mogonists still hold, it assuredly ought to occur, at times at
least, unaccompanied by, and apart from, its present universal
associates, which it assuredly does not in any portion of the
globe which has hitherto been explored. On the contrary,
the author was prepared to show, that the same predominant
mineral tj/pes, or the same average proportion of constituents^
characterized, alike the granites, porphyries, serpentines, green-
stones, slates and schists, of any tioell-defined division of the
Devon and Cornish group.

In the Lundy series we eliminate the important truth, how
egregiously we may be, and doubtless have been, imposed
upon by the varying accession of one deceptive compound ;
the minimum amount of hornblende in No. 2 demonstrating,
by the aid of the intermediate gradations, that its maximum
of imposition in Nos. 6 and 8 is simply a question of degree ;
while from the conditional fact or accident of its absence in

Phil. Mag. S. 3. Vol. 35. No. 233. Jtdy 1849. D

34 M. E. de Verneiiil's Note on the

No. 1, we learn what fabulous results have been assumed, and
what visionary fabrics have been imagined, and dreamy phan-
tasies indulged in, of primitial fire mist, and secular refrigera-
tion, and azoic and protozoic rocks, and gelatinous monads, and
progressive development, and strata identified in universal for-
mations, and the long catalogue and concatenation of chimaeras
and romance which in the present day is either substituted for
sober science, or which so poisons its well-heads that its current
throughout is corrupted and debased by it ; corollaries essen-
tially consequent on "the folly," as Playfair terms it, "of at-
tempting to explain the first origin of things," and which impli-
cates certain geologists in the something more than folly, viz.
that while they ostentatiously parade their trite and broad phy-
lactery, " denique non belle et probabiliter opinari, sed certo
et ostensive scire," they assume a definite sense and terms, and
draw physical land-marks, out of what are merely convenient
cabinet mineralogical distinctions, not definitions in nature,
but convenient distinctions in a constantly running and blend-
ing series, in which it is impossible to limit a genus or a species.
Bleadon, April 20,1849.

IV. Note on the Geological Structure of the Ast7irias, parti-
cularly in reference to the Nummulitic Eocene, and the Car^
bo7iiferoiis Palcsozoic Rocks of that Province {extracted from
a letter ofM.. E. de Verneuil addressed to Sir Roderick

I. MURCHISON*).

IN a tour which he is now making in Spain, M. Ed. de
Verneuil has observed, that on the frontiers of the pro-
vinces of Asturias and Santander, the nummulitic formation
overlies all the true cretaceous rocks, and that no form of the
genus Nummuli7ia, D'Orb., ever occurs in them ; thus fortify-
ing the generalization recently announced by Sir Roderick
Murchison, deduced from a study of the Alps, Apennines,
and Carpathians ; viz. that the nummulitic group of Southern
Europe, and which extends over such an enormous area in
Asia, is the true Eocene tertiary of geologists. The cretace-
ous or uppermost secondary rocks of the north of Spain con-
sist of two great stages, the lower of which is the Diceras
limestone, antl the uppermost a group of limestones and
argillaceous sandstones, &c. with Hippurites, Radiolites and
Orbitolites. The last-mentioned bodies have been supposed
to be Nummulites ; and hence has arisen the mistake of sup-
posing, that Nummulites and Hippurites are associated in those

• Communicated by Sir R. I. Murchison.

Geological Structure of the Asturias. 35

limestones of the south which represent the chalk of the north
of Europe. Above the zone of Orbitolites, is a yellowish lime-
stone with Spatangi, which representing the upper chalk of the
north, is widely developed at Santander, between the town and
the lighthouse.

The nummulite limestone then follows as the next deposit
in ascending order, and is overlaid, as in the Alps, by sand-
stone, &c. In this formation M. de Verneuil discovered, in
addition to Nummulites, the Serpula spirulaa, Conoclypus co-
noideuSi Ostrea crassissima or gigantea^ fossils so well known
in the nummulite rocks of the Alps, Vicentine and Crimaea.
This eocene group, whose fossils are so distinct from those of
the cretaceous system, nevertheless follows all the flexures and
dislocations of the latter, just in the manner recently described
by Sir Roderick Murchison in the Alps and Apennines. The
same relations, zoological and stratigraphical, are said (on the
authority of Don Amalio Maestre the Inspector of Mines of
the Asturias) to extend from Aragon towards Valencia.

In describing the principal features of the carboniferous
rocks of the Asturias (some of the peaks of whose limestones
rise to upwards of 8000 feet above the sea), M. de Verneuil
shows, that the chief seams of coal are fairly intercalated with
courses of limestone and schists charged with the well-known
British species Productus antiquatus, P. punctatus and various
marine fossils. In this and in other overlying stages with
conglomerates, &c. containing coal, there is, the author ob-
serves, no sandstone or schist which can have served as a
soil on which jungle or marsh plants can have grown ; and
seeing the alternation of the fossil vegetables with marine de-
posits, he concludes that these coal-fields, like many others,
and particularly those of the Donetz in Russia described by
Sir R. Murchison and himself, were formed in estuaries of the
sea by the transport and subaqueous deposit of terrestrial
spoils, and are not referable to the same origin as certain car-
boniferous strata of the British Isles, America, &c., the coal beds
of which are supposed to have been formed of vegetable masses
in situ. In the second stage of this carboniferous formation,
M. de Verneuil discovered, that courses of calcareous schists
were loaded with Fusulinas — a poiot of very great interest;
since these foraminifera have been described in the mountain
limestone of Southern Russia*, and were subsequently dis-
covered by M. de Verneuil in the carboniferous limestone of
the United States of America. Their occurrence at this in-
termediate station in Spain is therefore highly interesting in
extending our acquaintance with the uniformity of distribution
* See Russia in Europe and the Ural Mountains, vol. i.
D2

36 Mr. C. J. Hargreave's Analytical Besearches

of animal life in the palaeozoic ages. The coal-fields of the
Asturias (of which there are seventy workable seams) seem
therefore to be subordinate to the mountain limestone, like
those of the north of Northumberland, the south of Scotland,
&c. &c.

The Devonian system has been found to abound in the
north of Spain, chiefly through the researches of M. Paillette,
who has transmitted many of its fossils to France, where they
have been described by M. de Verneuil.

The Triassic and Jurassic systems are also stated to be con-
siderably developed in Spain, and like the palaeozoic rocks they
are highly dislocated.

In conclusion, the author remarks, that the interesting
region of the Asturias will soon be better known, first through
a very exact geographical map prepared by M. Paillette,
particularly in reference to its coal-fields ; and next by a gene-
ral geological map of the province by Don. G. Schultz, on
which that gentleman has been occupied during four years,
and which is spoken of as a work of great merit.

V. Analytical Researches concerning Numbers. By Chaules
James Hargreave, Esq.^ LL.B., FJi.S., Professor of
Juris'prudence^ University College^ London^.

THE theory of numbers is a branch of mathematics which
has either been regarded as not falling under the domi-
nion of analysis, or has eluded the researches of those who
may have attempted its application; so that, notwithstanding
the great powers and singular industry of the eminent men who
have devoted themselves to this science, it remains, so far as its
processes are concerned, nearly in the condition in which the
theory of probabilities would have stood, if the higher analysis
had not l)een applied to it. It abounds with theorems of
remarkable elegance; but is destitute of the processes, which
alone, in case of need, could render it a practical science.

Legendre, in his treatises on this subject, communicated as
the result of an observation of numbers in the first million, a
formula for determining the number of primes up to any given
limit; and adopting this formula as a law, he was conducted
to some theorems involving the application of analysis. ( Theorie
des Nomhres, vol. ii. § VIII.) That the formula thus given
by him is not really the natural law of primes, is apparent
from the circumstance that it involves a constant, or rather

* Communicated by the Author.

concerning Numbers. 37

two constants, whose values are assigned by experiment, and
which can have no natural connexion with the subject; and
as these constants are merely calculated so as to give as little
error as possible for the small limits within which the obser-
vations are confined, there is no a priori reason for supposing
that their assigned values remain permanent for numbers of
an order of magnitude far exceeding the observed limit.

The primary object of the following investigation is the
discovery of the laws regulating the occurrence of prime num-
bers by means of analysis; and it is evident that if this object
can be effected by the deduction of a simple analytical law,
we shall be in a position to deduce many curious and interest-
ing results connected with the subject.

The power of applying analysis to this subject is based upon
a principle, which at present it would be presumptuous to
rank amongst recognized forms of mathematical reasoning;
to wit, that the real analytical equivalent of the different
values of an indeterminate expression is the arithmetical mean
of those different values. It is satisfactory, however, to be
able to observe that this dogma is not propounded here for
the first time; but has appeared, at least as matter of induction,
under the high authority of Professor De Morgan. (Camb.
Phil. Trans., vol. viii. part 2. No. 15.) The present is not a
convenient opportunity for the discussion of this principle ; but
as it is likely to be introduced in some shape or other into
analysis, it is very necessary that the grounds upon which it
rests, and the subjects to which it may be lawfully applied,
and the manner of its application, should be analysed, and
recognized to a due extent. I hope on another occasion to
be able to advance some reasons for the conclusion, that this
principle may be introduced into mathematics without de-
parting from or unduly extending doctrines heretofore ad-
mitted. At present, I shall merely observe that I do not
regard it as probable that the principle in question, or any prin-
ciple analogous to it, is deducible from the fundamental axioms
of algebra ; that it may nevertheless be true in some definable
and useful sense; that, so far as experience leads us, no in-
congruity arises from the application of this doctrine, but that,
on the other hand, whenever an analytical equivalent is de-
duced naturally, it is found to coincide with the arithmetical
mean; and lastly, that the subject of this paper affords a
favourable case for its application, inasmuch as the results
which we propose to obtain are precisely of that average cha-
racter of which results flowing from such a principle might be
expected to partake.

In the course of this paper I shall have occasion to employ

38 Mr. C. J. Hargreave's Analytical Researches

/" dx
-, ; which, although

not used as commonly as logarithmic or trigonometrical func-
tions, has received a distinctive name (logarithm-integral) and
symbol (li.2?), and has been tabulated by Soldner from 0 to '99
and from I'l to 1280. The table is given in Mr. De Mor-
gan's DifF. Cal., pp. 662, 663. It will be useful to note the
following properties :

Px'^dx ,.- ^,,,

y„b^ =''("')'

(except when m= — 1, in which case
Jj^ =logloga;,) y ^ =li(6*), jY\xdx=x\\x--Yi{a^).

The following researches do not imply or assume any know-
ledge of the observed values or deduced properties of prime
numbers, except so far as is expressly mentioned ; but I have
not on this account thought it necessary to employ symbols in
lieu of well-known primes (such as 2, 3, 5, 7 . .), where the use
of the numbers places the expressions in a more familiar form.
The symbol p is used to denote a prime number in general ;
and accents or suffixes are attached when necessary for distinc-
tion.

Prop. 1. If

«"" "pi 2^ 3« 4^

where 1, 2, 3, 4 ... denote the series of natural numbers to
infinity, then

where 2, 3, 5... denote the series o^ prime numbers to infinity.

If we take the natural numbers beginning with 2, and strike
out from the series the first prime (2) and all its multiples,
then the second prime (3) and all its multiples, and so on
through the series of prime numbers, we shall have struck out
all the numbers in the following manner : the primes will have
been struck out, once; the composites of two primes, twice;
the composites of three primes, three times ; generally the
composites of m primes^ m times.

If we now go through the series again, and restore 2.3 and
all its multiples, 2.5 and all its multiples, 3.5 and all its mul-
tiples, and generally PxP'i. ^^^^ ^^^ ^^s multiples, going through
the series of primes, we shall have restored the composites of
2 primes, once ; the composites of 3 primes, three times ; the
composites of 4 primes, six times ; and generally the compo-

concerning Numbers. 39

sites ofm primes, m — -— times, being the number of combi-

nations of two things in m things.

If we go through the series again, and strike out 2.3.5 and
all its multiples, and generally PiP^Ps and all its multiples, we
shall have struck out the composites of 3 primes, once ; the com-
posites of 4 primes, four times ; and generally the composites

of 7» primes, m — — times, being the number of combi-

nations of three things in m things.

Repeating this process continually, alternately striking out
and restoring, the final result will be as follows :— The primes
will have been struck out once and never restored ; the com-
posites of 2 primes will have been struck out twice and restored
once ; the composites of 3 primes will have been struck out
three times, restored three times, and struck out once; the
composites of 4 primes will have been struck out four times,

4.3
restored -^ times, struck out four times, and restored once ;

the composites of 5 primes will have been struck out five times,

* ,5.4 . ^ , ^ 5.4.3 . ^ , 5.4.3.2

restored — - times, struck out times, restored

times, and struck out once ; and generally the composites of
m primes will have been struck out in all

m ^~ — + -^^ 273 ^-...±m+l times;

that is simply once; since this expression is 1— (1 — 1)"» or 1.
The general effect therefore of the whole of this process is,
that the original series of natural numbers is exactly exhausted.

This process is one of great simplicity, as it involves nothing
more than the mechanical process of determining prime num-
bers by exhausting the composites.

Bearing these considerations in mind, it will be immediately
obvious that the proposed series wanting its first term, or
P«-l, is

P (2 J V ^ I s ^ V

and, deducting both sides of this equation from P„,and dividing
by P,j, we have

=0-^)0-f)0-^)(-^)

which is the theorem proposed.

lO Mr. C. J. Hargreave's Analytical Researches

This theorem is arithmetically true, and may be verified
approximately by calculation, when 71 is greater than unity ;
but for other values of w, whether positive or negative, we do
not approximate to arithmetical truth by taking additional
terms of the series. If we multiply together a definite number
of factors of the form

(-D"'(-D"'0-D''-0-.-)"'.

we obtain the sum of the reciprocals of consecutive ordinals
up to the next prime beyond p exclusive : and besides this,
we obtain the reciprocals of an infinite number of scattered
ordinals, whose aggregate sum does not diminish without limit
as p increases. This may be expressed by saying, that in the
equation

the two infinities are not the same, and the difference between
them is a material consideration.

The proposition above given readily conducts us to expres-
sions for Bernoulli's numbers in terms of prime numbers;
which, however, we reserve for future discussion.

(\v \ X

— denote the whole number — when x is di-

visible by />, and the next whole number below — when x is

not divisible by p, then the continued product 1 .2.3.4.... ;r
or [.r] may be expressed by means of its prime factors in the
form

2G)<:0<5)-3G)<?)<?)-- /tXjXP- ...

all the primes up to x being employed.

This theorem may be deduced from the considerations put
forward in the first proposition ; but as I find that it is de-
monstrated by Legendre (Introduction, p. 10), I omit the
proof.

The familiar association of the arithmetical continued pro-
duct \_x\ with its algebraical extension r(a; + l), where Vx is
a solution of the functional equation (^{x-{-\)=x<^Xi conducts
us naturally to the investigation of an algebraical extension
for this continued product when resolved into its prime fac-
tors; an investigation which throws us back on the funda-
mental principles upon which algebraical extensions of this

concerning Numbers, 4-1

nature are based. Now in effecting such an extension, we
attach a notional continuity to expressions which in their
natural sense are not properly continuous, but proceed per
saltus ; and our power to do this arises from the circumstance,
that whatever discontinuity in the algebraical sense exists in

expressionso^theforml.2.3..a;, 1+ — + — + .. +— , logl +

log 2 + ..+ log .r, &c., such discontinuity is itself the sub-
ject of a regular and continuous law. The process is an in-
terpolation of all those algebraical forms which are necessary
to be interpolated, in order that expressions of this kind may
have continuous values for every value of x proceeding by
infinitely small increments, instead of proceeding by definite
equal increments.

Now prime numbers are not naturally anomalous any more
than ordinals are ; they are the elements of the ordinals ; and
the infinite series of natural primes is the framework or ske-
leton of the series of natural ordinals, the texture superposed
upon such framework being manufactured by a law which
we can express. The whole series of ordinals

1+2 + 3 + 4. + 5 + 6 + 7 + 8 + 9+10+114-12 +

is formed by the continued multiplication of the several series

2" + 2^ + 2^+23 + 2*+ 25 + 2^" + ..
3<^ + 3i + 3H3^ + 3'* + 3^ + 3« + ..
5f^ + 5^-\-5'^ + 5^ + 5'^+5^ + 5^ + .,

^0 +pl + p2 ^^3 ^^4 ^pb ^pG^„

where the sign + is used in the ordinary sense for the pur-
pose of multiplication, but in the result merely means juxta-
position. This is sufficiently apparent from the fact that the
above product gives every possible combination of primes and
powers and multiples of primes, and cannot give the same
number twice, since no one prime or any power of it can
be equivalent to any other prime or any power of it. In
effect, in the first theorem we resolved the infinite series of
ordinals into

(l-2)-Hl-3)->(l-5)-^..(l -;?)-'...,

which is the algebraical form of the expression last above
w^ritten.

Let us now denote the natural series of primes by

IS

42 Mr. C. J. Hargreave's Analytical Researches

and suppose ourselves not to have any previous acquaintance
with their properties further than necessarily flows from the
circumstance that they are the elements of which the natural
numbers are composed. We have then by virtue of this fact
the equation

where Py is the last prime in the series of ordinals up to ^ ;
and the question suggests itself, what meaning is to be attached
to the second side of this identity, when the first side is used,
not in the arithmetical sense, but in the extended sense which
is ordinarily understood by the term r(,r+ 1). What can we

propose as a proper analytical equivalent of ( — j. . ? To th

question it would perhaps be difficult to give a general satis-
factory answer; it will be sufficient for the present purpose to

express the analytical equivalent of ( ) ~ I — ) ' ^"^ *^

is submitted that if any such equivalent exists, it can only be

— in the ordinary sense. In this investigation x and p^ are

P\

symbols to which we do not assign a definite arithmetical

value ; we know merely that j9j is a prime. Now ( — ) niay

differ from the ordinary fraction — by any one of the quantities

12 3 jOi-2 Pi-1 , a; + Aar . ,.,

0, — , — , — , ...-^-i , ^-^ ; and may m like man-

Pi Pi P^ Pi Pi Pi
ner differ from the ordinary fraction by any one of the

same quantities ; and if we are at liberty to adopt in its sim-
plest form the principle before alluded to, — that the analytical
equivalent of an indeterminate expression is the arithmetical
mean of all its possible values, — we shall have no difficulty in
concluding that the proper expression for the difference in

A .7.' ^x

question is — ; for its value may differ from — by any one

of a set of quantities the arithmetical mean of which is zero.

It will be observed that in the arithmetical identity of which
we are speaking, we are at liberty to consider the series

+

as extending ad hifinitum^ without thereby impairing the truth
of the equation, or detracting from its purely arithmetical

concerning. Numbers. 43

't>

\py

character; for (-^) vanishes whenever—- is less than 1.

\py p^ its

Now in applying to the equation the principle of means in the
manner above suggested, it is proper to consider it in this ex-
tended form ; for if we suppose the series to stop so soon as

p^ exceeds ar, then in deducting I — ) + ( — 2 ) + • • fro^

j + ( 2 — ) + • • J we lose sight of the circumstance

that the number of terms in the latter expression is not neces-
sarily the same as that in the former expression ; or, in other
words, that the mean number of terms in the latter is neces-
sarily greater than the mean number of terms in the former.
Acting upon this principle of means, we equate

(^)+e-^)--((|;)-(~7)-")

to

^"(^+^-*-")'

which amounts in effect to this ; that if we write the first part
in the form

{(jXih-)-

(x+Ax)
and the other part in the form

then for the purpose of subtraction the ( — j + (— -2} + . • niay

be regarded as meaning the same thing in both.

Prop. 3. To investigate the law which regulates the occur-
rence of prime numbers in the ordinal series.

Let j: be a prime number occupying the place py in the
series of primes; and let x + Ax be the next prime number
occupying the place jo^+i in the series of primes. We have
then

T{x+l)^(p(^F)^-pJ^y- .,.p(jy)^y^

T{x + Ax + 1)

44 Mr. C. J. Hargreave's Analytical Researches

the X and a^+ A,r being properly the numerators of the expo-
nents. Now substitute for V{x-\-\) and r[x-\-iikX+l) their
respective algebraical approximate values

(27ra;)^(-j and (27r(^ + A:r))*(^^j ;

extract the a;th root of the first equation and the (o^-H- AA)th
root of the second ; and divide the latter by the former, re-
membering that the exponent ofj»y+i is in fact merely or

1 , Py+i
r— ; and we get

{w + ^xY^^'^(l+ ^\(27:{x + Lx)y^^'' {2'Kx) ^' ;

an equation for determining Ax in terms of :t'.

This equation becomes readily soluble if we avail ourselves
of an observed fact with reference to prime numbers, that Ax
is a small quantity as compared with x itself, at least in that
part of the series of ordinals which is at some distance from
the commencement. Taking then the logarithms of both sides
of this equation, and using the approximate expressions

log {x + Ax) = log X H ,

and

1 _ 1 Ax

x-\- Ax X ~ x'^'
we have

, Ax/ , 27r\ , I

A^=loga;+— (^1+ log— j +

2x

The approximate solution of this equation obtained by rejecting
the terms divided by x is

Ax= log j;;
and a more exact solution may be obtained by substituting
log X for Ax in the terms previously rejected ; which gives

A^=log a:(l + ^ log (27re) j ;

but the first solution is all that will ordinarily be required.

Now j/ being the number of primes up to x, if ^=(py, we
have

x + Ax=ip{y+l) = <py + <p'i/
nearly ; and therefore

Axov\ogx=i^'i/=—;

concerning Numbers. 46

and finally.

^=/,

dx
log^r

or the number of primes between the limits x and x' is li.r'— lia;.
If we take the more accurate value of Aa^, as deduced by the
above method, and make

and use the approximate value already obtained for determi-
ning the last term, we shall get

y=\\x-- log (27r)(log log^) +c;

so that the correction is scarcely appreciable.

In applying this formula, we must bear in mind, that as it is
a continuous algebraical expression derived from the applica-
tion of a principle of means, it represents not the absolute
number of primes which will actually be found between any
particular limits, but the average number which may be ex-
pected to occur within such limits, having regard to the general
law under which primes occur throughout the ordinal series.
The expression log x represents nearly the average distaiice
between two primes at the point x in the ordinal series ; and
with reference to that part of the ordinals which lies near this
point, that is, so near that log x has undergone no appreciable
change, it may be expected to indicate with tolerable accuracy
the average distance which a table of primes would show. The
larger the range over which we traverse, the more nearly
shall we be able to test the formula, or ascertain the nature
and extent of its deviation from truth ; and the largeness of
the range must be estimated with regard to the actual magni-
tude of the limits.

The formula for determining the difference between two
logarithm-integrals is a series of powers of t, where t denotes
the logarithm of the ratio of the limits; the series being con-
vergent with considerable rapidity when / is less than one.

If the lower limit be x^ the upper limit a?', and log — =^, and

> — — =«;, we have
log^

\y^\ix={a^-'X)v- i^V^|l + ^"g*^^^
3 — 3.2u + 3.2.1w2 4 — 4.3t;+4.3.2i;2_4 3 2.it;3 -|

^ 3.4 3.4.5 J'

of which a very few terms will suffice for our purpose.

4-6 Mr. C. J. Hargreave's Analytical Researches

The following Table was constructed, for convenience of

computation, with the value t=--\ so that the numbers pro-

ceed in a geometrical series whose common ratio is si. This
proceeds regularly from 100 to 180,804'; the limits following
this were selected in order to compare the results with the
number of primes counted from the tables by Legendre : —

Lower

Upper

Primes

Primes

limit.

limit.

computed.

counted.

Difference.

100

165

13-3

13

•3

165

272

200

20

•0

272

448

29-7

28

1-7

448

739

45-4

45

•4

739

1218

69-6

68

1-6

1218

2009

107-1

105

2-1

2009

3312

165-3

161

4-3

3312

5460

■ 256-5

256

•5

5460

9002

399-0

397

2-0

9002

14841

622-5

620

2-5

14841

24469

975-5

975

•5

24469

40343

1530-0

1517

13-0

40343

66514

2408-6

2398

8-6

66514

109663

3793-5

3794

-•5

109663

180804

5992-6

5982

10-6

180804

350000

13569-7

13572

-2 3

350000

400000

38960

3884

12-0

400000

700000

22722-5

22674

48-5

700000

1000000

2198.3-5

21958

25-5

1000000

2000000

704300

2000000

3000000

67916-0

3000000

4000000

66381-8

It will be seen from this Table, that at the commencement
of the numeral series, the formula is in excess to the extent of
about 1 in 600 ; but from the character of the investigation,
I am disposed to think that this error diminishes as we ad-
vance in the series. On the whole the coincidence is of a re-
markable character, having regard to the nature of the sub-
ject; forjudging merely from the apparently irregular occur-
rence of primes, it might be thought impossible that their law
should be represented in any sense by a continuous analytical
fo lunula.

Assuming the logarithm-integral to represent the number
of primes between its limits, it is easy to see how it be-
comes possible to frame a formula like that of Legendre's

•os^fifi/' ^^^'*^^ ^'^^ g^^^ approximately true re-
al least over a small range of the series.

( ^

Vloff a:*— !•(

Jog
suits,

The variation

of the logarithm is so slow as compared with that of the num-
ber, that it may be treated as constant within certain limits ;
and the numerical correction becomes necessary in conse-

concerning Numbers. 47

quence of the computation being made from the commence-
ment of the series, where the variation of the logarithm is
greatest.

With a view of applying the formula in somewhat higher
parts of the series, I have computed the primes from 2,010,000
to 2,019,000 at 620, while Burckhardt's Tables give 617 ; and
from 2,982,000 to 3,0 1 8,000 at 2,4 1 3, which agrees exactly with
the Tables ; but these ransfes are too limited to enable us to
judge of the formula.

Since the preceding table was computed, I have found the
following formula, which gives the most accurate and expedi-
tious method of calculating the logarithm-integrals of large
numbers :

lix'-Iia?= (a?'-^)t;-^^V{ D -/t;D + 2fVD2- . . } (^-^ V

where D denotes differentiation with regard to t.
When ^=1, this becomes

{3t^-'X)v-xv^{\-v{s-2)-\-v\6-'2s)-'iP{9s-~2^)
+ V*(120— 4.4s)— 1;^(265£ — 720) + ..};

the general term of the part within brackets abstracted from
its sign being

±i^-'(1.2.3..w)|l-/l -- + — -..+ — ^ \\

^ \ ^ 2^2.3 -2.3..njr

or

\n+l (w+l)(w + 2)"'~ (w+l)(w + 2)(n + 3) •*'/*

which diminishes as n increases, and is always positive. In
the form

V ™4-, T «. 8'»+i-e'» £"»/ -7182818 -5634.364

m m^\ m nr

_ -4645365 -3955996 _ \
w^ m'^ "/

it can be calculated with great ease, particularly when m is an ,
integer. The following are instances :

Primes from 300000 to 815484; computed 39089 ; counted 39082
1839.39 to 500000; ... 24890; ... 24883
331091 to 900000; ... 42819; ... 42778*.

The circumstance that log^ represents the average distance
between two primes at the point x in the ordinal series, gives

* I subjoin the following Table of logarithm-integrals, which will serve

48 Mr. C. J. Hargreave's Analytical Researches

us a perfect idea of the rate at which primes occur. Thus if
we wish to know at what point of the ordinal series the primes

1000

come at the rate of 50 per thousand, the answer is e*"
or e^°, which is about 485,000,000 ; that is, for many millions
before and after 485 millions, the rate of primes is 50 to the
thousand.

For ranges of moderate magnitude, the formula

af{\ogx' — \)—x{\ogx — l)
will be found to represent the number of primes between a?'
and X with considerable accuracy in any part of the series.
For since log x is the average distance between two primes
at Xi the average of these average distances from x to x' will
be

a^([ogx^—\)—x(\ogx—l)
a}—x '

and xl x^^x be divided by this expression, we obtain the for-
mula above written as the average number of primes between
y and X. This would give us for the primes between x and
Ix the expression

^ ^ X

log^ + 2log2 — 1 *^^ log a?+ -38629436'
which will be found to be nearly correct. The above formula

for any number up to about 1200,000,000 by one application of the for-
mula for li*' — \\x.

X.

iM^X.

Vix,

2-7182818

1

1-8951178

7-389057

2

4-9542360

2008553

3

9-933834

54-59815

4

19-63029

148-4133

5

4018532

403-4288

6

85-98970

1096-6333

7

191-3349

2980-958

8

440-2102

8103-084

9

1037-7084

22026-466

10

2487-8509

59874-14

11

6067-0276

162754-78

12

14955 153

442413-36

13

37193-320

1202604-3

14

93188-15

3269017-8

15

234237-22

8886110-0

16

594842-2

24154949-4

17

1523419-2

65659972-

18

3884686-0

178482268-

19

9957687-

485165153-

20

25622432-

concerning Numbers. 49

appears in some cases to give results more closely correspond-
ing with the Tables than are derived from the logarithm-inte-
gral. Thus for the primes from 100,000 to 1,000,000 it gives
68,853, the actual number being 68,901.

Prop. 4. To find the sum of any function (f) of the primes
up to A\ the wth prime.

If this sum (exclusive of the function of ^ itself) be denoted
by rI/«, we have {x being a function of w, say ft,n)

f(2) + f(3)+f(5) + ...-f<p(a(«-l)) =4'//^

f(2)+f(3)+f(5) + ... + <p(|^(n--l)) + 9(f*(«))=4'(«+l);
whence

and

^ J^ ^^ Q 2 dn 30 2.3.4 dn^

Now by the last proposition

,. J dx

n—i\x or dn=, :

log a?

whence

Cases of the above Theorem.

Case 1. Let (^x—x] then the sum of the primes up to x
inclusive is

or

c-\.\\{a'^)+-x+ —logx + ..;

that is, the sum of the primes from 3/ exclusive to x inclusive,
corrected by deducting half the difference between y and ^,
(for the other terms may be neglected), is equal to the number
of primes between j/^ and x'^.

This remarkable theorem, which connects in an unexpected
manner the values of the primes in one part of the series with
their number in another and remote part of the series, will
enable us to verify the theorem as to the number of primes,
and will confirm the conclusion that the relative error in de-
termining the number of primes diminishes as the numbers

Phil. Mag. S. 3. Vol. 35. No. 233. JuIj/ 1849. E

50 Mr. C. J. Hargreave's Analytical Researches

increase in magnitude. In determining (by the formula li 2000
— li 1000) the number of primes between 1000 and 2000,
there would be an error in excess of about 2 ; so that if we
sum the actual primes between 1000 and 2000, in order to
obtain the number of primes between 1,000,000 and 4,000,000,
we might expect to obtain a number varying from the theo-
retical number of primes between these limits by from 2000 to
4000 ; but as it will be seen that the error is not so great, and
that it is not permanently in defect, we may infer that the for-
mula for computing the number of primes is more correct for
large numbers.

The sum of the actual primes between 1000 and 2000 is

205,054, which leaves, after deducting -(1999 — 997), the

number 204,553 ; and the computed number of primes be-
tween 997^ or 994,009 and 1999^ or 3,996,001 is about
204,900. If we take in another prime, the difference lies in
the other direction; for the former number becomes 206,554,
and the latter about 205,908.

To take an instance in which the number of primes has
been counted, we find the sum of the primes from 241 exclu-
sive to 503 inclusive (with the proper correction) to be 16,219,
and the number of primes from 241^ or 58,081 to 503^ or
253,009 to be 16,326 ; and taking the next prime, the numbers
are respectively 16,727 and 16,861. If we had begun one
prime earlier, the error would have lain in the other direction.
These examples sufficiently illustrate the general character of
the theorem.

Case 2. Let (^x—x^\ then the sum of the squares of the
primes up to x inclusive is

c^-\\{f)^\x^^ ^^log^-;^i(4(log^)2 + 2log «;) + ...;

or the sum of the squares of the primes from y exclusive to x
inclusive is

Xiif) -\\{f) + - {x^-y^) + - (a? log X -y log j/) nearly.

Generally it will be found that the sum of the (wz — l)th pow-
ers of the primes from?/ exclusive to x inclusive is the number

of the primes between^"' and x'^ increased by ^(^'"~^— y"~0»

with further corrections involving the (m — 2)th and lower
powers of 7/ and x in combination with their logarithms, which
would be of small relative amount.

By giving to m fractional values, we shall find that the sum

concerning Numbers. 51

of the square roots of the primes from y exclusive to x inclu-
sive, diminished by - ( s/x— Vy)i is the number of the primes

from 5/^ to ^^; and a similar theorem may be expressed for
any other roots, or for roots of povi^ers.

As an example, the sum of the square roots of the primes
from 1789 exclusive to 2399 inclusive is 3638*5; from which
we deduct 3*4 for half the diflf'erence of the roots, leaving
3635 ; and it will be found by counting, that the number of
primes from 1789^ or 75,668 to 2399^ or 117,502 is 3631 ;
a degree of accuracy which arises from the circumstance that
between 1 800 and 2400 there is no great excess or defect of
primes from the average number.

The sum of the cube roots of the primes between the same
limits, duly corrected, is 1013; and the number of primes
between 1789^ or 21,717 and 2399^ or 32,115 is 1008.

Case 3. Let <^x= -; then the sum of the reciprocals of the

primes up to x inclusive is

Pdx 1 1 log a?

kJ xlogx 2x 12 a?*
or

c + log log ^ + 5— nearly.

u X

The sum of the reciprocals of the primes, therefore, from y
exclusive to x inclusive, is

° log^ 2\x y/'

It follows from this that the sum of the reciprocals of the
primes from any number to the prime next to its wth power is
nearly log w, whatever the number may be ; the corresponding
proposition for ordinals being that the sum of the reciprocals
from X to nx is nearly log7^, and is independent of the value
of a-. We also see that the sum of the reciprocals of the
primes up to a large number x differs only by a constant from
the sum of the reciprocals of the ordinals up to log x.

The constant c would require, like the corresponding con-
stant of the ordinal series (y or '5771213), to be determined
by computation. By employing values of a? up to about 900,
the constant appears to be nearly '267; but as at the com-
mencement of the series the actual primes differ sensibly from
what may be called the theoretical primes, it is difficult to
determine the constant thus with accuracy.

E2

52 Analytical Researches coticerning Numbers,

Case 4. Let (p^= -n; then the sum of the inverse squares

of the primes up to x inclusive is
/» dx

or

dx , 1 _ 1 ^^S ^ _
logo:' Ix^ 6 x^

The value of c is the sum of the series adinfinitunii for all the
other terms vanish when x is infinite. It was computed by
Euler at •454-2247.

Generally, we shall find that the sum of the inverse nih
powers of the primes up to x inclusive is nearly

''"*"^*\^^)+2^'

where c is the sum ad iTifinitum ; and similar formulae apply

to negative fractional powers. The logarithm-integrals may be

found by means of Soldner's table and formulae.

Case 5. Let <p^ = log^; then the sum of the logarithms of

the primes up to x inclusive is

/*, 1 , 1 \ogfx
c^Jdx+-\ogx+-~- ..

or

C + X+ ~ log X nearly.

This theorem, which imports that the sum of the logarithms of

the primes from 3^ exclusive to x inclusive is nearly x—i^ (more

1 x\
accurately x—y+ ;^log- ), may be verified by trial, and will

w y /

be found to be true of large numbers in an average sense. It
is true in the same sense as the formula for computing the
number of primes, and is in eff'ect identical with it. If we
take limits between which there are more than the average
number of primes, the sum of the logarithms will be too large,
and vice versa ; but as x increases, the sum of the logarithms
of the primes up to x becomes equal to x.

Case 6. If <p,2?=log f 1 — \ , we shall find approximately

On Electricity in the Act of Muscular Contraction, 53

which, as x increases without limit, approaches to c + log \ogos
or log log {x>^)i where x or s" is a constant, which may be found
by computation.

Now as X increases without limit, we have

log (l + ^ + ^ + [ +-. + 7,)=logiogM;

so that the expression to which (l — o) (^"o')

\}~~t) •••(! ) approximates arithmetically is not

as was before observed, but

>4-M-

1

■ + !■'

'-^14-

■■-h

The expression here discussed was calculated by Legend re,
and tabulated up to ^=1229. (See Tlieorie des JVombres,
tab. IX. vol. i.) The value of c, as derived from x= 1229, is
•581078; as derived from ,r=1213, it is -580693; and as de-
rived from ,27 = 94-7, it is '58101 ; and it is not improbable that
its theoretical value is the constant •5771213 of the ordinal
series. It may be observed, that the difference between this
constant and that which enters in the sum of the reciprocals
of the primes corresponds exactly with the analytical value of
this constant y ; for the value of this difference is

(| + logi) + (j + log|) + (i+log|) + ... «<Zm/.,

and the value of y is

(l+log.) + (l + logi) + (i+log|) + (l+!ogi) + ...
ad infijiitum.

The preceding investigations may be made available for the
determination of the law which regulates the occurrence of
numbers which are composites of two primes, of three primes,
&c. ; but I have not hitherto investigated this part of the sub-
ject with sufficient minuteness.

VI. On the Development of Electricity in the Act of Muscular
Contraction. By M. Becquerel*.

I HAVE repeated unsuccessfully the experiment of M. Du
Bois Reymond, relative to the production of an electric
current in the act of muscular contraction, making use of the
arrangements which he indicated in a letter addressed to
* From the Comptes Rendus for May 28, 1849,

54 On Electricity in the Act of Muscular Contraction.

M. Arago by M. de Humboldt, dated the 17th of May*, ex-
cluding however all those secondary causes which could give
rise to electric currents, excepting that one the action of which
is described.

I shall commence by recalling to mind the observations which
I made in studying the electric effects obtained with a con-
denser, the plates of which were made of platinum or copper
gilt ( Traite de VElectricite et du Magneti&me, t. v. 2^ partie,
page 10) :—

" The electro-chemical effects produced on the contact of
acid solutions with the liquids which moisten the fingers, must
be taken into account. In these various reactions the acids
acquire the positive electricity, which is transmitted to the
plate, and the liquids which moisten the fingers the negative
electricity. With the alkalies the effects are inverse."

It follows from this, that if one of the plates is covered ex-
ternally by a very thin layer of hygrometric water, and that
it is touched with a finger moistened with perspiration, elec-
tric effects, resulting from the reaction of the perspiration
upon the water, ensue. It is also produced when a finger in
a great state of transpiration is applied upon one of the plates,
after having been previously moistened with water; in this
case the water acquires the positive electricity, and the con-
trary electricity flows into the body of the experimenter. If
we add to these effects those which take place when foreign
bodies are adherent to the skin, we must conceive that a large
number of complex electric effects would be produced in
plunging two fingers, as is done by M. Du Bois Reymond,
into two capsules filled with water in which are contained two
plates of platinum in communication with a multiplier. This
is not all : when, in virtue of these various causes, a current
has circulated in the liquid and in the wire, the two plates of
platinum are polarized in opposite directions, as may be shown
by withdrawing the fingers and establishing the communication
between the two capsules by means of a siphon filled with the
same liquid as that which they contain. This current, during
the first few moments, having the same intensity as the primi-
tive current, annuls it; but if, in the act of contraction, the
finger of the contracted hand become more or less immersed
in water, the inverse current may be less or superior to the
direct current. I guarded not only against the effects of the
inverse current, but also against the effects resulting from the
greater or less immersion of the fingers by smearing with fat
those parts of the fingers which might temporarily come into
contact with the liquid. By proceeding in this manner, I found
it impossible to observe the effects described by M. Du Bois
Reymond.

* See Phil. Mag. vol. xxxiv. p. 643.

L 55 ]

VII. Note relative to the Electricity developed by Muscular
Contraction. By M. C. Despretz *.

THE note which I have the honour of communicating, is a
simple enumeration of the experiments which I made with
the view of reproducing the phaenomena announced by M.
Du Bois Reymond of Berlin t. I shall not discuss these phaeno-
mena, my only object being to reproduce them. This appears
to me the most philosophical manner of proceeding in the ap-
preciation of a new fact. We are not sufficiently acquainted
with the intimate nature of bodies, of heat, light or electricity,
we know too little regarding vital phaenomena, to reject h
priori a physico-physiological fact, however singular it may ap-
pear at first sight. The wisest and most prudent course is,
first to confirm it, and afterwards by a profound analysis of
the phaenomenon, to ascertain the various sources of error to
which it is exposed. It must not be forgotten that Galvani's
researches upon animal electricity have given rise to one of
the most important discoveries of modern times.

I shall not enter further upon the history of the subject, in
doing which I should have to quote numerous researches, and
particularly those of the illustrious philosopher who made
known to the Academy the principal result obtained by M.
Reymond, and whose name is connected with so many import-
ant researches which have been made since the end of the last
century.

I have not inserted in the Comptes Rendus the results of the
experiments which I alluded to at the last meeting of the Aca-
demy, because these results did not appear to me sufficiently
demonstrative. The only conclusion I should deduce from my
first experiments, would be the uncertainty which the inter-
vention of the metallic plates in galvanometers appears to me
to throw upon the results of many experiments, as I have had
the honour of stating to the Academy.

The galvanometer which I used was made by M. Ruhm-
korff, whose skill is well known. The diameter of the wire was
Y^^th of a millimetre, and its length 800 metres. The wire
made about 1800 convolutions round the frame of the appa-
ratus. The delicacy of the instrument is shown by the fol-
lowing numbers.

A copper wire |ths of a millimetre in diameter, when im-
mersed to a depth of 2 centimetres, afforded a deflection of 3°
in distilled water, 25° in the water of the river Seine, and 68°
in a solution of chloride of sodium, containing from four to five
per cent, of the salt. ^

Plates of gold, the surfaces of which were nearly one square
• From the Coviptcs Rendus for May 28, 1849.
t Comptes Rendus, May 21; and Phil. Mag. vol. xxxiv. p. 543.

56 M. Despretz on the Electricity

centimetre, afforded under the same circumstances deflections
of 11°, 24° and 85°. The gold, which was perfectly pure,
had been recently prepared at the Mint of Paris, in the labo-
ratory of M. Pelouze and M. Peligot. The needle, when set
free, took about half a minute in moving from 50° to zero.

I was not at first acquainted with M. Reymond's method of
proceeding. In my earliest experiments, two cylindrical
conductors were held in the hands, and when the needle had
returned to zero, or had acquired a perfectly stationary posi-
tion, one of the arms was powerfully contracted ; the deflec-
tion was then observed, and when the needle had again be-
come stationary after the cessation of the contraction, the other
arm was strongly contracted, also observing the deflection.

These first experiments were made with common copper
conductors. But for the sake of avoiding the objection which
might arise from the ready oxidation of this metal, I had
them covered with gold-leaf. Other conductors were coated
with silver, platinum and gold.

The experiments were made by three persons. Were there
no occasion for using galvanometers, we should be inclined to
believe that silver, and especially gold and platinum, which
preserve their polish and lustre in contact with moist air,
would be appropriate for these experiments, on account of
their unalterability. This is however not the case; silver,
gold and platinum afford currents which are almost as strong
as copper. When the platinum conductor is held in the
hand, and the needle has become stationary, merely touching
it with one finger more, or less, is sufficient to change the posi-
tion of the needle several degrees.

In these experiments the needle was deflected 50°, 75° and
even 90°. When one of the conductors was squeezed power-
fully, the needle moved in one direction, and when the other
conductor was squeezed, the needle moved in the same or in
an opposite direction.

It is indispensable to repeat these experiments several times,
without which we should be liable to errors. Thus it happens
that the deflections of the needle occur alternately in one and
the other direction ; but on multiplying the experiments, we
find that the deflections frequently take place in the same di-
rection, although the compression is produced first by one and
then by the other arm. If the chemical action was regular
like that of a watch-spring, we ought to obtain currents in the
opposite direction. We only experimented in this way, be-
cause, on the one hand, we were unacquainted with M. Rey-
mond's method of proceeding ; and on the other, we thought
that silver, and especially gold and platinum, when simply
held in the hand without any compression, would only afford

developed by Muscular CofUraclion. 57

a very weak current. But experience unfortunately proves
that gold and platinum are under these circumstances as im-
pressionable as brass, if I may be allowed to use such an ex-
pression. I have repeated M. Reymond's experiment several
times, both following rigidly and varying his method of pro-
ceeding.

I first wished to ascertain whether the instrument, which I
had not yet used, was sensible or not to changes of tempera-
ture. For this purpose, I heated one of the places at which
it was soldered to the melting-point of wax, the communication
being established by the hands between the two plates ; I also
augmented the temperature of one of the two solutions of
common salt, by immersing in it glass tubes filled with boiling
water, the communication being always kept up by the hands;
in neither case did I observe the slightest deflection, which
might be anticipated from the known properties of thermo-
electric phaenomena; nevertheless it appeared to me of use to
verify this in the present instance. To avoid the effect of a
more or less deep immersion of the metallic plates, in conse-
quence of the introduction of the fingers, 1 partly covered
these plates with black wax, so that the uncovered surface was
always in contact with the solution.

As regards the fingers, I attempted to immerse them to the
same extent in all the experiments, having found that in
plunging successively one, two or three, or more fingers, or a
single finger to a greater or less depth, the intensity of the
deflections varied. This result indeed had been anticipated.
I had even had some long kinds of copper thimbles gilt, so as
to regulate the immersion better. But I abandoned this
method of proceeding, because it differed too much from that
adopted by M. Du Bois Reymond.

In experiments made according to M. Du Bois Reymond's
process, the alternate contraction of each arm has sometimes
afforded deflections in the same, sometimes in the opposite
direction.

In other experiments, each arm was successively contracted
out of the water, and on each contraction the vessels were
connected by means of the fingers. In others, large capsules
were used, so as to allow more freedom of motion of the hands,
and so as to permit the immersion of the closed hands, either
contracted or not contracted. The results of these two series
of experiments are sometimes favourable, sometimes contrary
to the assertion of M. Reymond. The necessity of multiply-
ing the experiments is very distinctly shown in this case.
The results of two or three experiments agree with the results
announced by M. Reymond ; and then, if they are continued,
opposite results are obtained. A singular fact is also remarked

58 M, Despretz on the Electricity

in these experiments, viz. that the fingers are influenced much
in the same way as metallic conductors ; they lose part of their
efficacy by repeated immersions.

I was desirous of reducing the experiment to a greater
amount of simplicity. I replaced the galvanometer by a frog
which was properly prepared. Several persons, separately or
in connection, having strongly contracted one of their arms,
in vain endeavoured to produce convulsive movements, by
connecting the two arms by means of the most sensible parts
of the animal. Nevertheless with a very fine copper wire and
a plate of zinc, without the use of any liquid, very marked con-
tractions were produced both before and after the experiment.

I also endeavoured in vain to deflect a very delicate astatic
magnetic needle, by the union of the two hands, whilst one
hand was strongly contracted. Finally, I attached a cylin-
drical gilt conductor to the back of each hand by silk cord : the
contraction of one or the other arm did not perceptibly change
the deflection of the needle, which amounted to 10° from the
simple contact. The effects of the contact were increased in a
marked degree by moistening the back of the hand with a few
drops of salt water ; but the contraction of one or the other
arm did not produce deflections alternately in one or the other
directions.

These three experiments appear to me to be under more
favourable conditions than those of M. Reymond. The re-
sults of them are removed from the intervention of the im-
mersion of metallic laminae in saline solutions, which is always
somewhat obscure. Unfortunately they only furnished nega-
tive results.

In conclusion, if we are only to admit as true that which is
clearly demonstrated, we think that the experiments detailed
in this note show, that if the contraction of one arm gives rise
to an electric current, this current is not appreciable to our
present means, at least to those which we have employed.

We are however far from believing that the tetanic contrac-
tion of a limb does not give rise to the decomposition of a
certain quantity of electricity. The friction of the parts upon
each other, and the unequally heated state of heterogeneous
parts would give rise to electric decompositions ; but recompo-
sitions ensue immediately. This is probably the case in all the
chemical actions which occur in the oeconomy.

Until chemistry has discovered a metal or an alloy which
does not afford any current by the contact of liquid conductors,
we shall always be exposed to numerous errors in researches
upon the currents of animals and vegetables.

The galvanometer is a very valuable instrument, but it re-
quires a very large amount of skill and prudence on the part

developed by Muscular Contraction. 59

of the experimenter. If it is made but slightly sensible, it
only indicates powerful phsenomena ; if it is made very deli-
cate, it obeys the slightest perturbating causes. It is not im-
possible that a large number of experiments upon the currents
in animals and vegetables may merely arise from illusions, and
that what is attributed to animal and vegetable currents, may
be nothing more than the action of liquids upon the plates of

f;old or platinum of galvanoscopes, or upon other different
iquids. If the two plates of gold of a galvanoscope are in-
serted in any direction in a potato which has either budded
or not, in an apple, or a cabbage-stalk, or the flesh of beef;
if any two parts of the skin, slightly moist, are touched with
these same plates, we have currents; if first one and then
the other plate be withdrawn in succession, and after having
washed and wiped it, it be replaced, the current is reversed ;
if the plates are more or less deeply immersed, reversions may
also occur.

It is possible that the convulsions experienced by the frog
from the contact of the crural nerves with the muscles of the
legs, may depend only upon the heterogeneity of the liquids
which moisten these parts. It is possible that the permanence
of the direction of what is called the current of the frog may
be owing to a different alterability of the extremities of the
animal by the various solutions employed in these experiments.
In the experiment as arranged for determining the true or
false current in the frog, we merely require to substitute for
the animal a cord of thread impregnated with common salt,
and one of the ends of which has been touched with the stopper
of a bottle of sulphuric acid, and the other with the stopper
of a bottle of nitric acid, to reverse the current a great many
times, as is done in the case of the current of the frog.

There is one experiment upon this subject which would
have a certain value without being decisive, it is that of the
action of a circuit of frogs upon a magnetic needle.

I arranged a chain of frogs in the same manner as the pairs
of a voltaic pile are arranged ; this chain traversed a bell-glass,
beneath which a very delicate astatic needle was suspended.
I did not observe any distinctly-appreciable effect at the mo-
ment at which 1 united or separated the extremities of the
chain. Had an effect been obtained, the objection of the ac-
tion of the heterogeneous moist parts would still remain.

It does not appear to me that the existence of electric cur-
rents in frogs and plants is a perfectly proved fact. I speak
openly, submitting my doubts to those philosophers who have
made most interesting, and in some cases very ingenious ex-
periments upon this subject.

" • [ 60 ]

VIII. Some facts relative to the Spheroidal State of Bodies^
Fire-OrdeaU Incombustible Man, Sj-c. By P. H. Boutigny
(d'Evreux)*.

IN the year 241, Sapor or Chapour ordered the Magi to do
all in their power to persuade them and bring them back
to the faith of" their ancestors. It was then that one of the
pontiffs of the dominant religion, Adurabad-Mabrasphand,
offered to submit to the fiery ordeal . . . . " He proposed
that eighteen pounds of melted copper, issuing from the fur-
nace, all hot, should be poured on his naked body, on con-
dition that, if he was not injured by it, the unbelievers should
yield to so great a miracle. The trial was said to be attended
with such success, that they were all converted." The his-
torian adds, with an air of doubt, certainly allowable in such
a matter, " We see that the religion of Zoroastre had also its
miracles and its legends f."

Now this fiery ordeal, undergone with such success by
Adurabad-Mabrasphand, is in plain truth an experiment of
primitive facility and simplicity, and which is anything but
miraculous.

I stop here an instant, for I fancy that I see the smile of
incredulity rise on the lips of some who do me the honour of
listening to me ; — that smile, so discouraging to one who is in-
sincere, but which only heightens the ardour of him who in-
tends to practise no deception, and who does all in his power
not to deceive himself.

To such persons then I would offer this encouragement;
the little that I have still to relate appears improbable, but
it is true, and that is enough. Having said this, I continue.

In France, in England, in Italy, wherever I have had
occasion to speak of bodies in the spheroidal state, I have
met with persons who have put to me this question : May
there not be some connection between these phasnomena and
that presented by men who run barefooted over liquid metal (?)
still incandescent, or who plunge their hand into molten lead,
&c. J? To all I have answered, Yes, I believe that there is
an intimate relation between all these facts and the spheroidal
state. And then, in my turn, I put this question : Have you
witnessed the fact which you tell me? And the answer has
invariably been in the negative.

I avow that all these on-dits and the marvellous legends

* From the Comptes Rendus for May 14, 1849.
f Dictionnaire historique, critique et bibliographique, t. xxvii. p. 417-
I I have alluded to these facts in the work entitled, Nouvelle branche
de Fhysiqxic^ or E'tudes sur les Corps a VEtat spheroidal, p. 36.

M. P. H. Boutigny on the Spheroidal State of Bodies, Sfc. 61

which I had read in various works* on the fiery ordeal and
incombustible men, admitted without reserve by some, obs-
tinately denied by others, excited my curiosity greatly, and
gave me a great desire to verify all these phaenomena, and to
recall them to the recollection of contemporary observers ; for,
alas ! all this is as old as the world ; nil sub sole novum.

I wrote first to my friend Dr. Roche, who passes his life in
the midst of the blast furnaces of the Eure, and who is the
physician of a portion of the Cyclopean population who feed
them. I requested of him precise particulars. All that he
could ascertain was, that a man named La Forge, of from
thirty-five to thirty-six years of age, very corpulent, walked
step by step barefooted on the pigs after the casting : but he
had not seen this. This was not enough to dispel my doubts.

I then applied to a foundry at Paris, where I was laughed
at and shown the door. I retired, hanging down my ears,
thinking over the difficulties of verifying a single fact, and
such a simple one.

Subsequently I was fortunate enough to meet with M. Alph.
Michel, who lives in the midst of the forges of Franche-Comte.
M. Michel promised me, with the greatest kindness, to inquire
into these facts, and to report upon them if desired.

The following is an extract from the letter which he did me
the honour to write to me, dated the 26th of last March : —

" On my return home, I did not fail to obtain information
from the workmen of the facts of the case (the immersion of
the finger in the incandescent melted metal), and most of them
laughed in my face, which did not deter me. Lastly, being
one day at the forge of Magny, near Lure, I put the question
again to a workman, who answered that nothing was more
simple ; and, to prove it, at the moment when the metal in a
state of fusion issued from a Wilkinson, he passed his finger
into the incandescent jet. A person employed in the esta-
blishment repeated the experiment with impunity : and I
myself, emboldened by what I saw, did the same ... I may
observe, that, in making this trial, none of us moistened his
finger.

" I hasten, Sir, to acquaint you with this fact, which seems
to support your ideas on the globular state of liquids ; for the
fingers being naturally more or less humid, it is, I think, to
this moisture passing to the spheroidal state, that we must
ascribe their momentary incombustibility."

The following are the experiments which I have made : —

I divided or cut with my hand a jet of melted metal of five

* Des Erreurs et des Pr4jug4s r^pandtis dans let diversea classes de la
Soci^te, t. xii. p. 183.

62 M. P. H. Boutigny on some facts relative to

to six centimetres, which escaped by the tap, then I immedi-
ately plunged the other hand in a pot filled with incandes-
cent metal, which was truly frightful to look at. I invo-
luntarily shuddered. But both hands came out of the ordeal
victorious. And now, if any thing astonishes me, it is that
such experiments are not quite common.

I shall of course be asked, what precautions are necessary
to preserve oneself from the disorganizing action of the incan-
descent matter? I answer. None; — only to have no fear, to
make the experiment with confidence, to pass the hand ra-
pidly, but not too rapidly, in the metal in full fusion.

Otherwise, if the experiment were performed with fear, or
with too great rapidity, the repulsive force might be overcome
which exists in incandescent bodies, and thus the contact with
the skin be effected, which would undoubtedly remain in a
state easy to understand.

To form a conception of the danger there would be in
passing the hand too rapidly in the metal in fusion, it will
suffice to recollect that the resistance is proportionate to the
square of the velocity, and, in so compact a fluid as liquid iron,
this resistance increases certainly in a higher ratio.

The experiment succeeds especially when the skin is
humid ; and the involuntary dread which one feels at facing
these masses of fire, almost always puts the body into that
state of moisture so necessary to success; but by taking some
precautions, one becomes veritably invulnerable. The fol-
lowing is what has succeeded best with me : I rub my hands
with soap, so as to give them a polished surface ; then, at the
moment of making the experiment, I dip my hand into a cold
solution of sal-ammoniac saturated with sulphurous acid, or
simply into water containing some sal-ammoniac, and, in de-
fault of that, into fresh water.

Regnault, who has occupied himself with this subject, says,
" Those who make a trade of fire handling and holding it in
the mouth, sometimes employ an equal mixture of spirit of
sulphur, of sal-ammoniac, of essence of rosemary, and onion-
juice." All volatile substances, we see, which, in evaporating,
render a certain portion of heat latent.

Let us now seek the rational explanation of these facts.

We have the formula m, c t^ which gives the quantity of
heat contained in any body.

Let m be the mass expressed in kilogrammes,
c the specific heat of the body,
t its temperature.

But here the factor m must be abstracted, because there is
no contact between the hand and the metal in fusion, and the

the Spheroidal State of Bodies., Sfc. 63

experiment presents no difference, being made either with 10
kilogrammes of metal, or with 1000 kilogrammes. The sen-
sation which is felt is the same in either case, and this is
readily conceived, knowing the repulsive force of incandescent
surfaces which is opposed to the contact of any body.

The finger or the hand is then isolated in the midst of the
mass in fusion, and thus preserved from the disorganizing
action of the incandescent matter. I repeat, that the mass
must be abstracted.

There remain the two factors c, t. I will suppose, and it
is a sufficient approximation, that the value of c = 0'15, and
that of ^ = 1500 degrees, the temperature of the metal in
fusion; now the product of 1500 degrees x 0'15 = 225. Thus
the epidermis of the experimenter would only be exposed to
225 degrees of heat. Undoubtedly this is a respectable quan-
tity of caloric, but it is too high, as we shall see.

There is no contact between the hand and the metal ; this,
in my estimation, is a fact positively established. If there is
no contact, the heating can only take place by I'adiation, and
it is enormous, it must be acknowledged ; but if the radiation
is annulled by reflexion, and it is so, it is as if it did not exist,
and, definitively, the operator is, so to say, placed in normal
conditions.

I think that I have established, a long time ago, the fact
that water in the spheroidal state has the property of reflecting
radiating heat*, and that its temperature never attains that of
its ebullition ; whence it follows that the finger or the hand
being humid, cannot rise to the temperature of lOO'^ Centig.,
the experiment not continuing long enough to permit the hu-
midity to evaporate entirely.

To recapitulate what I have stated on this point, I say, —
in passing the hand into any metal in fusion, it becomes iso-
lated ; the humidity which covers it passes into the sphei'oidal
state, reflects the radiating caloric, and does not become
heated enough to boil. This is all.

I was right then in saying at the outset, this experiment,
dangerous in appearance, is almost insignificant in reality.

I have often repeated it with lead, with bronze, &c., and
always with the same success f.

* Nouvelle branche de Physique, or Ijltudes sur les Corps a I'^^tat sphe-
roidal, pp. 24 et seq. and 13^2 et seq. See also our two letters to the Aca-
demie des Sciences, dated the 14th and 21st of July, 1845. In the places
indicated will be found the explanation of this phaenomenon.

t The experiments on the cast iron were made in the foundry of M. Da-
vidson, atLa Villette ; and, on the bronze, in that of M. Nerat, Rue Pierre-
Levee. I am happy to have an opportunity of publicly thanking these
gentlemen for their kind assistance.

[ 64 ]
IX. Proceedings of Learned Societies.

ROYAL SOCIETY.

[Continued from vol. xxxiv. p. 532.]

March 8, " A DDITIONAL Observations on the Osteology of the

1849. -^ Iguanodon and Hylaeosaurus." By Gideon Alger-
non Mantell, Esq., LL.D., F.R.S., V.P.G.S., &c.

This memoir is supplementary to the author's former communi-
cations to the Royal Society on the same subject, and comprises an
account of some important additions which he has lately made to
our previous knowledge of the osteological structure of the colossal
reptiles of the Wealden of the South-east of England.

The acquisition of some gigantic and well-preserved vertebrae and
bones of the extremities from the Isle of Wight, and of other in-
structive specimens from Sussex and Surrey, induced the author to
resume his examination of the detached parts of the skeletons of the
Wealden reptiles in the British Museum, and in several private col-
lections; and he states as the most important result of his investi-
gations, the determination of the structure of the vertebral column,
pectoral arch, and anterior extremities of the Iguanodon. In the la-
borious and difficult task of examining and comparing the numerous
detached, and for the most part mutilated bones of the spinal column,
Dr. Mantell expresses his deep obligation to Dr. G. A. Melville,
whose elaborate and accurate anatomical description of the vertebrae
is appended to the memoir. The most interesting fossil remains are
described in detail in the following order.

Lower Jaw. — Since the author's communication on the lower jaw
of the Iguanodon, published in the Philosophical Transactions, part
ii. ] 848, he has discovered the right angular bone, which was pre-
viously unknown: from the circumstances under which this relic
was found, he considers it probable that it belonged to the same
individual as the teeth figured in Plate XVIII. of the Philosophical
Transactions for 1848.

Vertebral column. — The vertebrae hitherto assigned to the Igua-
nodon consist of the middle and posterior dorsal and anterior cau-
dal, as identified by means of the Maidstone specimen in the British
Museum : the cervical, anterior dorsal, lumbar, and posterior and
terminal caudals, were previously either undetermined or referred to
other genera of saurians. The investigations of Dr. Melville have
established the important and highly interesting fact, that the cervi-
cal and anterior dorsal vertebrae of the Iguanodon were convexo-
concave— that is, convex in front and concave behind — as in the
fossil reptile of Honfleur termed Sireptospondylus, and in the exist-
ing pachyderms ; the convexity gradually diminishing, and the an-
terior face of the body of the vertebra becoming flat, in the middle
and posterior part of the dorsal region. The supposed Streptospon-
dylian vertebrae of the Wealden (named S.major by Professor Owen
in British Association Reports on fossil reptiles) are, in the opinion
of the author and Dr. Melville, the true cervical vertebrae of the

Royal Society. 65

Iguanodon. The convexo-concave type of vertebrae was not con-
fined to a single genus — the Streptospondylus of the Oolite — but
prevailed in two, and probably in several, genera of extinct sau-
rians of the secondary geological epochs; in like manner as the re-
verse form, the concavo-convex, predominates in the existing cro-
codilians and lizards.

Other large vertebrae found with ribs and bones of the extremities
of the Iguanodon, and referred by Professor Owen to one or more
species of Cetiosaurus, are regarded, in consequence of the peculiar
structure of the neural arch, as belonging to the posterior dorsal and
lumbar vertebrae of the former colossal reptile ; and certain some-
what angular vertebrae, also previously assigned to a species of Ce-
tiosaurus, are presumed to be the middle and distal caudals of the
Iguanodon.

The Sacrum, of which portions of several examples belonging to
individuals of much disparity in size have been obtained, is shown
to consist of six anchylosed vertebrae ; not of Jive, as stated by Pro-
fessor Owen ; and the typical specimen in the possession of Mr. Saull,
which the author figures and describes, is adduced in proof of the
correctness of this opinion. The anterior vertebra, and the two
posterior ones, are much larger and stronger than the three inter-
mediate elements which occupy the centre of the arch of the sacrum.

Pectoral arch. — A perfect scapula discovered in the strata of Til-
gate Forest, and which corresponds with the coracoid bone, provi-
sionally assigned to the Iguanodon in the memoir of 1841 (Phil.
Trans. PI. IX. fig. 11), Dr. Mantell has been enabled to refer to that
re^itile, by the fortunate interpretation of portions of two scapulae
which are preserved in the Maidstone specimen, but had not pre-
viously been recognized as such. As the clavicles were long since
determined, the essential elements of the pectoral arch are now as-
certained, and the author gives a restored outline of this important
part of the skeleton, based upon these data.

Humerus. — A humerus three feet long, discovered by Mr. Fowles-
tone in the Isle of Wight, has been ascertained by the author to belong
to the Iguanodon, from the presence of a small but corresponding
bone in the Maidstone fossil. This bone, from its disproportionate
size in comparison with the femur with which it is collocated — being
one-third shorter — was formerly assigned by Dr. Mantell to the fore-
arm ; but the large humerus from the Isle of Wight, which, except
in magnitude, is identical with that from Maidstone, leaves no doubt
upon the subject. It is now therefore, for the first time, ascertained,
that in the Iguanodon, as in many fossil and recent reptiles, the an-
terior extremities were much shorter and less bulky than the poste-
rior. The radius and ulna are still undetermined, but the author
states that there are some imperfect bones in his former collection,
now in the British Museum, which he thinks will be found to belong
to the fore-arm.

Hinder extremities. — The colossal magnitude of the Iguanodon is
strikingly shown by some femora- and leg-bones recently discovered.
One femur is 27 inches in circumference, and must have been 4 feet
¥hiU Mag. S. 3. Vol. 35. No, 233. July 1849. F

66 Royal Society.

8 or 10 inches in length ; and a tibia, found with the same, is
4 feet long.

Dermal scutes and spines. — The author figures and describes se-
veral dermal scutes and spines, and states that a microscopical exa-
mination of the large angular bones of the Hylaeosaurus (Phil. Trans.
184'1, PI. X. fig. 1), supposed by him to be ossified dermal spines,
but which Professor Owen regarded as the abdominal extremities of
ribs, proves the correctness of his own opinion ; their structure being
identical with that of the acknowledged dermal scutes.

In the summary which concludes the memoir, Dr. Mantell states
that the facts described, confirm in every important point the phy-
siological inferences relating to the structure and habits of the Igua-
nodon and Hylaeosaurus, enunciated in his former communications;
and thus, after the lapse of a quarter of a century, he concludes his
attempts to restore the skeletons of the colossal saurian herbivores,
of whose former existence a few water-worn teeth and fragments of
bones were the only indications, when, in 1825, he first had the ho-
nour to submit to the Royal Society a notice on the teeth of the
Iguanodon.

March 15. — "Researches in Physical Geology." Part XL By
Henry Hennessy, Esq. Communicated by Major Beamish, F.R.S.

In this communication the author states that, having in Part I.
(read to the Society in December 1846) endeavoured, by general-
izing the hypothesis on which is usually founded the theory of the
earth's figure, not only to improve that theory, but also to establish
a secure basis for researches into the changes which may have taken
place, within and at the surface of the earth, during the epochs of
its geological history, his object here is to discover relations between
the interior structure of the earth and phenomena observed at its
surface, and also the effects of the reaction of the fluid nucleus, de-
scribed in Part I., upon the solid crust. This memoir is divided
into sections, each containing a distinct investigation ; and the state-
ment of the geological results is given at the end.

I. The Pressures of the Shell and Nucleus at their surface of contact.

In the investigation of these pressures the earth is supposed to
consist of a nucleus of fluid matter inclosed in a solid shell, the inner
and outer surfaces of which are spheroidal, but nearly spherical ;
and both shell and nucleus are supposed to consist of strata varying
in density according to some unknown inverse law of the radii. The
pressure at the inner surface of the shell is conceived to be due to a
constant pressure, which is the same for every point, and a variable
pressure, arising from the difference in form of the surface of the
nucleus and inner surface of the shell. On these suppositions, simple
expressions for the pressure on any stratum of the nucleus and on
the shell's inner surface are deduced.

II. The Variation of Gravity at the earth's surface.

The author does not assume in this investigation that the laws of
arrangement of the particles composing the shell and the nucleus

Royal Society, 67

are necessarily the same ; so that the expression which he obtains
for gravity at any point on the earth's surface, besides being a func-
tion of the latitude of that point, and of the radii and ellipticities of
the shell's inner and outer surfaces, contains functions depending on
the constitution of the shell and nucleus. He states that this ex-
pression for gravity is not merely speculative, but that it will be
found to assist in explaining certain apparent anomalies detected by
observation in the variation of gravity at the earth's surface, as well
as in pointing out the limits assigned by observation to the thickness
of the crust.

III. The Laws of Density of the Shell and Nucleus.

According to the author's views in a subsequent section, it ap-
pears that the solidification of the earth could not proceed simulta-
neously from the centre towards the surface, and from the surface
towards the centre. He therefore, in determining the laws of den-
sity of the shell and the nucleus, restricts his investigations to the
latter case, in which the solidification proceeds from the surface to-
wards the centre.

IV. The Forms of the Strata of the Shell.

The author conceives a surface to exist which may be called the
effective surface of separation of the perfect fluid of the nucleus and
the imperfectly fluid portion adhering to the shell, the form of which
surface will depend on the pressures which the fluid exerts. As it
may be shown that the pressure of the perfect fluid will not be con-
stant, the surface of separation will tend to assume a form different
from that of the inner surface of the shell. If we admit that the
matter composing the nucleus becomes denser in assuming the solid
state, the author concludes that the inner surface of each stratum
added to the shell will be more oblate than its outer surface ; and
that thus the tendency will always be to render the inner surface of
the shell more and more oblate. He then deduces an expression
for the ellipticity of the fluid surface.

V. The principal Moments of Inertia of the Earth.

From his investigations the author concludes that, as the thick-
ness of the shell increases, the difference between the greatest and
the least moment of inertia of the earth also increases ; which con-
clusion is independent of any knowledge of the absolute laws of
density of the earth's interior.

VI. On the existence of a Solid Nucleus within the Earth.

The conclusion arrived at here is, that if a solid nucleus existed,
as the pressure on it would be continually diminishing, while its
temperature would remain nearly constant, this nucleus, instead of
increasing in magnitude, would tend to return to its original fluid
state.

F2

68 Royal Society.

VII. The directiojis of the Fissures in the Shell which might be prO'
duced by the action of the pressures in Section I.
The author states that the tendency of the variable pressure is in
the first instance to produce fissures parallel to the equator ; that
when such a fissure was once commenced the tendency would be to
propagate it along a parallel of latitude, until the force of the ten-
sions became sufficiently lessened by the separation of the extended
portion of the shell ; and that similar fissures would be formed si-
multaneously and symmetrically on each side of the equator. Sub-
sequently, as may readily be deduced from Mr. Hopkins's investiga-
tions, the tendency will be to form fissures at right angles to those
previously existing. If, however, the constant pressure were far
greater than the variable, the directions of the fissures would be go-
verned chiefly by accidental causes ; but if a fissure commenced, it
would continue to be propagated in the great circle coinciding with
its first direction, unless accidental causes should alter its course.

VIII. On the existence of a Zone of least disturbance in the Shell.

The author investigates analytically the position of this zone, and
from the results of his investigation, points out the conditions under
which it will exist, and also the consequences that will follow from
its non-existence.

IX. This section is devoted to the calculation of some of the con-
stants contained in the formulae of the preceding sections.

The following are the geological deductions from the foregoing
investigations : —

1. The stability of the axis of rotation of the earth will progress-
ively increase during the process of solidification.

2. By employing the values of the constants obtained in Section
IX., it appears that the thickness of the earth's crust cannot be less
than 18 miles, and cannot exceed 600 miles.

3. The earth's primitive ellipticity, when entirely fluid, was less
than its present ellipticity ; but their difference may be neglected.

4. If a zone of least disturbance existed near the parallel of mean
pressure, the directions of great lines of elevation should be in ge-
neral parallel or perpendicular to the equator. Its non-existence
there, which observation seems to show, proves at least that the va-
riable pressure did not predominate over the constant. Since, as yet,
observation goes to prove that such a zone does not exist on the
earth's surface, we must provisionally conclude that the constant
pressure greatly predominated over the variable, and, consequently,
that the directions of the lines of elevation must be comparatively
arbitrary.

5. That great friction and pressure exist at the surface of contact
of the nucleus and shell, is shown from the conclusions arrived at in
Section IV., combined with the important result obtained by Mr.
Hopkins in his second memoir on Physical Geology (Phil. Trans.
1840, p. 207).

6. The amount of elastic gases given off" from the surface of the
nucleus rapidly decreases as the thickness of the shell increases.

Hoyal Society. 69

7. The expression obtained for the variation of gravity shows that,
if the angular velocity of rotation of the earth remained unchanged,
the waters on its surface would tend to accumulate towards the
equator, for the increase of gravity, in going from the equator to the
poles, would be less according as the shell's thickness increased.

March 22. —"An Account of the Aurora Borealis of the 17th of
November ISiS." By the Rev. Charles F. Watkins. Communicated
by the Marquis of Northampton, V.P.R.S.

The author states that : " About half-past 7 p.m. the sky assumed
the appearance which it usually does immediately preceding the ac-
tion of what are called the Northern Lights. In the northern half
it was quite clear for about forty-five degrees from the meridian, of
a pale blue, and covered with a faint light, such as generally ushers
in the moon at her rising. Towards the east and west this light
gradually diminished, and south of those cardinal points the dimness
as gradually thickened.

" Soon after eight the coruscations began by the usual lambent
strokes of a shining filmy matter, like the sudden shooting forth and
instantaneous retroceding of a serpent's tongue. They commenced
in the north-east, and shot upwards in an angle of about 70 degrees
of inclination towards the south, and to about 60 degrees in length,
more or less, leaving the sky clear to the north, and in a manner
gradually chasing the clouds, upon whose receding bounds they
glanced further to the south.

" In a short time the same kind of electrical action commenced
in the north-west quarter of the heavens, and continued simultane-
ously with that from the north-east, both increasing in rapidity, in-
tensity and depth of colour ; till at length an entire hemispherical
arch of crimson and purple, but with uneven edges, spanned the
heavens from east to west, and remained suspended there for seve-
ral minutes. By degrees this arch broke up into separate masses of
highly and parti-coloured clouds, resembling those which are seen
floating about after the setting of an ardent sun. Meanwhile the
lighter coruscations continued, — now glancing upwards on the north-
ern edges of the clouds, which were still slowly receding to the south,
and now shooting up beneath them as they steadily retreated. At
the same time others of a redder hue played now alternately, and
now in union with them.

" About a quarter past nine an extraordinary phenomenon oc-
curred, such as I never before witnessed ; the zenith assumed the
appearance of a crimson coronary apex to distinct but connected
bands of various shades of crimson, green and purple, in which the
crimson prevailed, flowing down from thence like a canopy, encir-
cling the upper portion of the heavens, which to me presented the
inside view of a ribbed and vaulted cupola. By degrees this beau-
tiful creation dissolved, and the body of clouds, against which the
electrical forces seemed to have been in hostile pursuit, fled away to
the south ; the elementary action ceased : a silent calm returned,
and nothing but the tranquil light, still shining in the north, re-
mained to indicate the recent scene. The wind had blown with a

70 Royal Society.

fresh but steady breeze from the north-west, during the continuance
of the phenomenon.

*' Without entering at present into any disquisition upon the causes,
I will now state the meteorological results which I immediately an-
ticipated and haVe seen to follow these atmospheric phenomena.

" I have observed, and have stated my observations for some years
past, that the certain result of all meteoric coruscations and irides-
cences in the sky, is a fall of rain, snow or hail, — on this general prin-
ciple, that the condensation of the crystalline particles of floating
vapours which ensue upon electrical action, must be followed by pre-
cipitation ; and these coruscations and iridescences are both the
reflected evidences of such condensation of crystalline matter, and
therefore the harbingers of such precipitation. It is the case with
solar and lunar rainbows, falling stars, mock-suns, halos, lightning,
aurora, and that undefined pearly lustre which sometimes appears
in the neighbourhood of the sun.

"Accordingly, on the following morning, Saturday the 18th, I
found the barometer had sunk considerably, and the wind had veered
round from north-west to south-west, against the course of the sun,
both in general, and especially when united, the forerunners of rain.
Accordingly at 2 o'clock p.m. a smart shower came on in Northamp-
ton, but was of short duration. At 9 p.m. a heavier shower was ex-
perienced at Brixworth ; and in the course of the night, but I cannot
say at what hour, I was awakened to a still heavier shower ; but the
quantity of rain that had fallen did not seem to have affected the
ground much on the following morning, and therefore I conclude
that it was not great.

*' Sunday the 19th was fine and bright; the wind went up to the
westward, and the barometer rose rapidly — a general indication of
an early change. Towards morning of Monday the 20th, another
shower fell, and the wind went back to the south-west with a falling
barometer. In such cases I generally find that rain ensues about
midday, or at least when the wind and sun meet in the south-west.
But on this occasion it continued blowing strong all the day, and
for some time in the night with increased violence. But at last the
wind fell, and was succeeded for awhile by heavy rain, thus verify-
ing my anticipations on this particular occasion, and the general
theory which I have discussed."

April 19. — "On the Meteorology of the Lake District of Cum-
berland and Westmoreland." By John Fletcher Miller, Esq. Com-
municated by Lt.-Colonel Sabine, R.A., For. Sec. R.S., &c.

This paper contains the results of meteorological observations
made during 1848, similar to those made in the same district in
preceding years, which were last year communicated to the Society.
On these results the author remarks that the fall of rain in the lake
district, during the year IS^S, greatly exceeds the amount in any
other year since the register was commenced in 1844- ; and that
there is a similar excess with reference to the number of wet days.
The total depth of rain, in 1848, at Seathwaite, the wettest station,
was 160*89 inches ; and of this quantity, 114'32 inches fell in the

Intelligence and Miscellaneous Articles. 7 1

six months, February, July, August, October, November and De-
cember. In February there fell the unprecedented quantity 30-5.5
inches.

The mountains flanking the lake-district valleys increase in alti-
tude with great regularity towards the head or eastern extremity of
the vale, and it appears that it is there that the greatest depth of
rain is invariably found. The amount increases rapidly as the sta-
tions recede from the sea, and towards the head of the valley the
incremental ratio is exceedingly great. At Loweswater, Buttermere
and Gatesgarth, about two miles apart in the same line of valley,
the depths of rain were respectively 76 inches, 98 inches and 133'5
inches.

From the observations of the thermometer, the author concludes
that the climate in the mountain valleys in this district is milder and
more equable, not only than in the open country in their immediate
vicinity, but also than in that considerably to the south. This he
attributes to the lakes giving out during the winter the heat absorbed
by them in the summer, and to the radiation from the rocky moun-
tain breasts in the valleys, but principally to the heat evolved in a
sensible form by the condensation of enormous volumes of vapour.

Last summer a pair of Rutherford's self- registering thermometers
were stationed by the author on the summit of Sea Fell Pike. He
states that from the maximum thermometer no correct readings
could be obtained ; but that the minimum gave the following : —
July, 22°: August, 24°; September, 18°; October, —6°; November,
—6°; December,— 9°. It appears that on the night between the 2nd
and 3rd of January the minimum thermometer indicated the extra-
ordinary low temperature — 34'°Fahr. : at the same date a naked
thermometer on grass at Whitehaven fell to +4°, and one on raw
wool to — 2°-8.

The author states that the results obtained from the mountain
gauges during the last year, are in strict accordance with those of
the two preceding years, and thus confirm the correctness of the
conclusion drawn from them in his former paper, " that the quantity
of rain increases from the valley upwards to an altitude of about
2000 feet, above which it begins to diminish." He does not, how-
ever, by any means infer that the law which appears to regulate
the distribution of rain in the mountain district of Cumberland will
equally apply to every similar locality.

X. hitelligence and Miscellaneous Articles.

ON THE AURORA BOREALIS OF FEBRUARY 22, 184'9.

To the Editors of the Philosophical Magazine and Journal.
Gentlemen,
BEG leave to occupy a small space in your veJuable journal for
a notice of the Aurora Borealis which I observed on the 22nd
of February of this year.

About ten minutes to seven there was a low arch of white light,

I

72 . Litelligence atid Miscellaneous Articles.

with many streamers ; the height of this arch, estimated by /3 Dra-
eonis, was about 8°. Again, at 7^^ 45", there was a brilliant display
of sti-eamers, and an arch which was about 12° in altitude. There
was also at the height of 3° or 4° a long sinuous line of white light.
A day or two afterwards I was in Northamptonshire, not far from
Banbury, and found that on the night in question the arches had
been noticed at considerable altitudes : my observation then became
of use ; for having a base line of as nearly as possible twenty miles,
and the small angle accurately taken, the angle at the other end being
large, a considerable inaccuracy in this angle will not greatly affect
the result. If we take the crown of the arch to have been in the
zenith of this station at 7^ 45™ p.m., as I was informed at that time
it was about over head, and could not be seen without going out of
doors, we shall find the height of the crown of the arch to have been
41 miles, or about 22,400 feet. From a rough estimate of the space
which the arch subtejided in azimuth, the distance between its feet
was twelve or fourteen miles, which rested, as it appeared, on con-
fused masses of auroral light in the N.E. and N.W., which must
have been about the height of the ordinary cirrus. The true shape
of the arch therefore appears to have been a long flat curve, of which
the subtense was equal to six or seven times its altitude.

It seemed also that the long sinuous line which I mentioned as
seen through the arch was formed of a number of these arches at a
much greater distance, the direction of which was not in a straight
line, though possibly parallel to one another.

From frequent observation, I believe that the streamers which
usually attend the display of Aurora are parallel to the earth's sur-
face and to one another, and that their convergence is apparent only,
and produced by perspective. Probably also, whenever the elec-
tricity in this state is in sufficient quantity and of opposite kinds,
arches are formed, the true shape of which appears to resemble the
magnetic curve. The varying proximity of these electro-magnetic
clouds will also very well account for the disturbance of the needle.
I am, Gentlemen,

Your obedient Servant,

Rose Hill, Oxford, June 15. John Slatter.

ON LIgUID STORAX AND BALSAM OF PERU. BY M. KOPP.

The author states, that having in preceding memoirs studied the
resins of benzoin and the balsam of Tolu, there remained to complete
the general history of the balsams to examine the balsam of Peru
and storax.

Balsam of Peru had already yielded MM. Fremy and Plantamour
very interesting results. M. Fremy had determined the presence of
cinnamic acid, cinnamein and several resins : in some species of
balsam of Peru he met with a solid crystalline matter, to which he
gave the name of metacinnamein. According to this chemist, when
cinnamein is submitted to the action of potash dissolved in alcohol,
it is converted into cinnamic acid, and peruven, which is a liquid
body.

Intelligence and Miscellaneous Articles. 73

According to M. Plantaraour, there are besides formed under these
circumstances cinnamic aether and a new acid, the carbo-benzoic.

M. Kopp states that his researches confirm the results of M. Frdmy,
but not those of M. Plantamour.

Storax has been examined with much care by M. Simon of Berlin,
who found an essential oil in it, styrol, a crystalline body, styracine,
cinnamic acid and several resins. He stated that styracine is trans-
formed by potash into cinnamic acid and liquid styracone.

These results are quite exact, only the author has not assigned
the true composition to the isolated bodies.

The author observes that he has already shown that styrol is iden-
tical with cinnamen or cinnamol (C'<^ H***), which is obtained by the
dry distillation of cinnamate of copper, or of a mixture of cinnamic
acid and caustic barytas. M. Kopp's researches also prove that
great analogy of composition exists between storax and balsam of
Peru.

Styracine, which may exist either in the amorphous or viscous
state, or crystallized, is identical in the former condition with cinna-
mein, and in the second with metacinnamein. Its formula is C*
jjis 02. Peruven is identical with styracone, its formula being
C ' H^^ O. The transformation of styracine into cinnamic acid and
styracone under the influence of caustic potash, is expressed by the
following equation : —

C18 H>8 02 + H20 = C9H« 02-I-C9 H'2 O.
Styracine. Cinnamic acid. Styracone,

Styracine then possesses strong resemblance to neutral fatty mat-
ters, which, under the influence of alkalies, are converted with the
absorption of an atom of water into fatty acids and glycerine.

As storax is the most readily treated and least expensive of these
diff'erent bodies, the author selected it for his experiments.

The first operation is to distil the storax with five or six times its
weight of water, in a copper alembic furnished with a refrigeratory.
An oil floats on the condensed water, which is to be poured off^, dried
by chloride of calcium, and distilled at 290° F. ; it is then cinnamen
or pure cinnamol. It is not advantageous to employ in the distilla-
tion water containing carbonate of soda in solution, for it causes the
mass to rise too readily and afterwards to run over. The residue
of the distillation is boiled with a weak solution of carbonate of soda,
which removes the free cinnamic acid, and cinnamate of soda is
formed which remains in solution. This operation is to be repeated
many times, till at last, especially when the mixture cools, it becomes
more and more spongy, and retains in its interstices a viscid, yellow-
ish oily matter. The watery liquids containing the cinnamate of
soda and a slight excess of carbonate, and also a little resinate of
soda, are to be much concentrated, and then decomposed with excess
of boiling hydrochloric acid. The greater portion of the impure
cinnamic acid is deposited in the liquor in a concentrated state in
the form of a heavy brown oil, which solidifies on cooling, and the
aqueous liquid is filled with crystals of cinnamic acid. The resinous
matter is to be removed, and the crystals, after being strongly pressed
and washed with a little cold water, are to be distilled from a glass

74 Intelligence and Miscellaneous Articles.

retort. The first product of the distillation is cinnamic acid nearly
pure ; the last products are rendered impure by empyreumatic oils ;
by dissolving, however, this impure acid in boiling distilled water
and filtering, the oil remains on the filter, and the filtered liquor is
filled with very white and perfectly pure crystals of cinnamic acid.
This is the most ready and least expensive process for obtaining this
acid in a state of absolute purity.

The resinous, ductile, spongy matter containing the yellow opake
liquid in its pores, becomes when squeezed more and more compact,
and the yellow liquid flows from it ; this is to be filtered, the opera-
tion goes on very slowly, and the surface of the liquid readily
solidifies. By this means a brownish yellow oily matter is obtained,
which after some time becomes a stellar crystalline mass of impure
Btyracine. In order to purify it, it is dissolved in about ten times its
weight of alcohol at 122° F. ; the solution is poured off and subjected
to a low temperature. The styracine then crystallizes in very fine
white flexible needles. The compact resin from which the styracine
has been pressed becomes hard and brittle by cooling. It still retains
a considerable quantity of styracine, and it is advantageous to employ
it in the preparation of styracone ; there is thus obtained an additional
quantity of alkaline cinnamate, mixed with the resins; to eff^ect
this it is put into an alembic, with a concentrated solution of potash
or soda, and distillation is to be cautiously performed. A milky
liquid passes over, which when saturated with common salt yields
on its surface a creamy matter, which gradually unites into an
oily stratum ; it is to be removed, filtered, and rectified. There
is thus obtained a colourless liquid, which boils at about 490° F.,
crystallizes at a low temperature, becomes solid at 46°, and has a
peculiar odour. It is styracone. In the alembic there remains a
blackish brown and very alkaline liquid, in which there float numer-
ous mammillated grains of a yellowish colour, consisting of a mixture
of cinnamate and resinate of soda. The liquor may be filtered in a
funnel containing broken glass ; the resinate is to be washed with a
little water, which, added to the alkaline liquor, may be employed
to decompose a fresh quantity of storax. When water is added to
the globules, a resinous matter is deposited, and the solution contains
much cinnamate and some resinate of soda ; the cinnamic acid and
the resin are to be precipitated by hydrochloric acid ; these two
substances are to be separated by boiling water or solution of am-
monia, which does not dissolve the resins. To obtain the latter in
a pure state they must be successively washed with acidulated and
ammoniacal water, and lastly with boiling water. The diff'erent
resins are separated by means of their diflferent solubility in alcohol,
sether, and pyroxylic spirit. They are hard and brittle, not readily
fusible, and but slightly coloured.

Styracine is the most interesting substance contained in storax. It
may exist in two conditions : crystalline and fusible at 100° F., and
liquid, viscid and uncrystallizable. When pure crystals of styracine
have been melted, the liquid frequently does not solidify on cooling.

Sometimes also on operating on storax, the styracine is obtained in
a liquid uncrystallizable state, especially when it has been left for

Intelligence and Miscellaneous Articles. 15

"to

too long a time in contact with acids, for the purpose of separating
the last traces of soda.

When styracine is treated with the caustic alkalies, it combines
with them, and forms a solid mass consisting of agglomerated grains.
By the application of heat, styracone distils, and cinnamic acid is
obtained. Submitted to the action of chlorine, chlorinated styracine
is obtained. By distilling this compound under the influence of
chlorine, a volatile chlorinated liquid and a chlorinated crystalliza-
ble acid are procured; the latter very readily forms salts. With
nitric acid, styracone forms oil of bitter almonds, hydrocyanic and
nitrobenzoic acids ; with chromic acid it gives hydruret of benzoil,
benzoic acid and resin ; with concentrated sulphuric acid, it yields
cinnamic acid and a brown substance, soluble in water and insoluble
in aqueous saline solutions. — L'Institut, Juin 6, 1849.

IDENTITY OF BROOKITE AND ARKANSITE.

We learn by a note from Professor Miller, dated the 2nd of May,
that he has found an exact agreement between the forms and angles
of a mineral from the United States, lately described by Professor
Shepard, and named Arkansite, and the previously established species
Brookite ; and as both consist almost entirely of oxide of titanium,
they must, we conclude, be regarded as varieties only of the same
mineral. — En.

ON THE ESTIMATION OF MOLYBDIC ACID. BY M. H. ROSE.

Molybdic acid, MoO^, may be estimated in the state of sulphuret
by precipitating its sokitions, rendered acid, with sulphuretted hy-
drogen. This method possesses some inconveniences : on one
hand, the precipitation always takes place slowly, and the washings,
which have usually a blue colour, require to be heated with solution
of sulphuretted hydrogen to precipitate the last portions of molyb-
den : on the other hand, it is requisite to calcine the brown sulphu-
ret of molybden obtained, in order to convert it into gray sulphuret
MoS% the weight of which serves for calculating the quantity of
molybden.

M. H. Rose finds it more correct and convenient to estimate the
molybdic acid by reducing it in a current of hydrogen gas to the
state of perfectly fixed oxide of molybden. He uses in this opera-
tion a platina crucible, which has a tubulated cover, by which the
hydrogen gas is conveyed. The heat of a spirit-lamp is to be era-
ployed, in order that the temperature may not be raised high enough
to reduce any of the oxide of molybden to the metallic state. The
weight of the oxide of molybden obtained serves for calculating
that of the molybden or the molybdic acid. — Joum. de Ph. et de Ch,,
Janvier 1849.

ON GLAIRINE. BY M. BON JEAN.
This substance is a vegeto- animal matter produced at the sul-
phurous spring of Aix in Savoy. According to M. Duby, who has
examined it microscopically, it consists of extremely minute frag-
ments of a plant, of an extraordinarily fine, close, undulating tissue,

76 Intelligence and Miscellaneous Articles.

which is insoluble in water, and has the appearance of an animal
remain.

Glairine is produced by the immediate action of the air on the
sulphurous water, and is deposited on the pavement of the pumps.
It retains a large quantity of water, which it does not lose by long
exposure to the air : it is not entirely expelled below 104° F. Thus
dried it is quite colourless, completely inodorous, of a horny appear-
ance, and is reduced to about one-tenth of its M^eight ; when water is
added to it, it is rendered again mucilaginous, becomes nearly of its
original size, but remains inodorous. When dried and thrown upon
burning charcoal, it gives the smell of burnt horn, without any trace
of sulphurous acid, and the gases which it yields turn reddened lit-
mus paper blue. The absence, in this experiment, of sulphurous
acid seems to indicate that this substance contains no sulphur ; it
will soon be shown that it contains so little, that it can only be
isolated by means of aether. Water, alcohol, oil of turpentine, nitric,
hydrochloric, sulphuric, phosphoric, oxalic, acetic acids, &c., solution
of chlorine, dilute alkalies, all dissolve a small quantity cold, and a
little more when heated, but some of them occasion peculiar modi-
fications in it. The nitric, concentrated hydrochloric acid, and
liquid chlorine, immediately destroy the gray colour which it acquires
out of water and restore its natural whiteness. Separated from these
acids, it becomes more gray by exposure to the air : other acids do
not decolorize it. Alkalies precipitate it from solution in acids in
white flocculi which have a bluish reflexion. The nitric solution,
filtered and evaporated to dryness in a small porcelain capsule, leaves
a yellowish sharp residue, which is slightly acid, diificultly decom-
posable in a strong heat, and insoluble in water and in alcohol :
glairine does not decompose nitric acid unless it be heated. When
hydrochloric acid decolorizes glairine blackened by contact with the
air, it assumes a yellow colour, derived from the formation of a per-
salt of iron. This shows that this organic matter contains peroxide
of iron in combination, derived, unquestionably, from the carbonate
of iron which the water holds in solution. Concentrated sulphuric
acid, instead of decolorizing it, like the fore-mentioned acids, im-
parts to it the colour of wine dregs, which becomes lighter when acidu-
lated water is added. The caustic alkalies do not act upon it
when cold ; but when heated a green colour results, which acids
cause to disappear immediately. Bromine also decolorizes it ; but
at first it gives it a red colour, and the decoloration of the glairine is
not perfect until all the bromine is volatilized. If it should retain a
yellow tint from some remaining bromine, washing with distilled
water renders it perfectly white. Iodine colours it brick-red ; and
this colour does not disappear, either by long exposure to the air or
frequent washings. Alcohol and oil of turpentine dissolve a small
quantity, and acquire a slight yellow tint ; alcohol becomes sweetish,
and its consistency is sensibly increased. If these two liquids be
evaporated to dryness in a porcelain capsule, the lower portion is
carbonized by slightly increasing the heat.

Glairine is totally insoluble in aether. If they be mixed in a well-
stopped phial, and shaken occasionally during two or three days, the

Litelligence and Miscellaneous Articles. 77

aether when filtered leaves by evaporation small rounded grains of
perfectly pure sulphur ; they are yellow and briUiant, of the size of
a pin's head, and when thrown on a burning coal burn with a fine
blue flame and the disengagement of sulphurous acid.

When glairine is gradually heated on a platina crucible, it loses
its interposed water slowly, and even begins to be decomposed
before it has parted with the whole of it ; towards the end of the
calcination it exhales the odour of burnt horn, without any sensible
disengagement of sulphurous acid, and leaves a coaly residue. It
does not fuse, and it is difficult to incinerate it ; it does not lose
its odour by numerous washings with cold water, but imparts a
very distinct one to it, with a sweetish taste, without giving it
colour ; long boiling takes away the greater part of it ; the solu-
tion has a strong smell, and the residue is very small. This liquor
when filtered is yellowish, has a sweetish animal taste, is not muci-
laginous, and does not coagulate on cooling -, when evaporated to a
syrupy consistence in a porcelain capsule, it colours the sides of it
strongly yellow. The residue is of a deep yellow, with a slight
smell and bitterness ; the sulphuric and nitric acids, whether con-
centrated or diluted, do not sensibly act upon it. When glairine is
subjected to dry distillation in a glass retort placed in a reverberatory
furnace, it swells at first, and boils in the water which it retains inter-
posed. This water soon begins to distil by drops, is colourless, has
a strong smell of animal matter, and the apparatus is filled with
vapours. The odour of burnt horn soon replaces that of animal
matter, and drops of a yellow colour then fall into the receiver.
Lastly, when the heat becomes very strong, the retort contains char-
coal, and the neck is covered with a black substance, of which a few
drops only fall into the receiver with the yellow liquor and imme-
diately solidify. The yellow distilled liquor has a strong burnt odour
and taste, with slight bitterness. It reddens litmus feebly, and dis-
solves in all proportions in water and alcohol, ^ther does not dis-
solve it, but separates a small quantity of yellow fatty matter, which
it leaves by evaporation ; it is insoluble in water, but very soluble in
alcohol.

The coaly residue of the distillation treated with distilled water
yielded a slightly alkaline solution ; during distillation the gases
disengaged restored the blue colour of reddened litmus. The dry
residue of the distillation was a very light, black and friable charcoal,
which yielded 0"75 of ash composed of silica, carbonate of lime, and
peroxide of iron. No trace of iodine could be detected.

The preceding experiments on glairine lead to the following con-
clusions : it contains verj'^ little nitrogen and no iodine ; it dissolves
sparingly in water, alcohol, oil of turpentine, and rather more readily
in concentrated acids, from which the alkalies precipitate it in bluish-
white flocculi ; heat in all cases increases the solvent power of the
liquids ; it is quite insoluble in aether, which isolates perfectly the
small quantity of sulphur which it retains interposed between its
molecules ; it becomes rapidly of a more or less blackish-gray
colour when taken from the water and exposed to the air ; but it is
sufficient to treat it with nitric or hydrochloric acid, bromine or

78 Intelligence and Miscellaneous Articled,

chlorine, to restore its natural whiteness : sulphuric acid, far from
decolorizing it, imparts to it the colour of wine-lees ; the concen-
trated alkalies render it green when heated, and the alkalies destroy
it ; when in water it has but very little odour, but as soon as taken
from it, it acquires a most disgusting smell, which is not dissipated
by long exposure to the air, at least while it retains a little water ;
nor is it got rid of by much washing with cold water, or by long
boiling, although in the latter case the greater part of it disappears.
Lastly, it becomes perfectly inodorous by thorough drying in a stove,
assumes a horny apj)earance, and is reduced to about one-tenth of
its weight. — Journ. de Ph. et de Ch., Mai 1849.

ON GLAIRIDINE. BY M. BONJEAN.

The author observed that when the sulphurous waters above de-
scribed become mixed with rain-w^ter, another vegeto-animal matter
appears, to which he has given the name of glairidine.

The principal characters of this substance are, that it is of a deep
gray colour, instead of being colourless, like glairine ; it is inodorous,
and remains so even when exposed to the air. Long exposure to
the air does not alter its colour ; but if a glass bottle be immediately
filled with it, it soon acquires a smell, which in a few days becomes
as disagreeable as that of glairine taken from water. If it then be
taken from the bottle and exposed to the air, it becomes quite inodo-
rous, and dries perfectly in a few days ; on the contrary, it has been
shown that glairine does not lose its interposed water till exposed
to a heated stove. Glairidine is not decolorized either by any acid
or by liquid chlorine. Like glairine, it renders hydrochloric acid
yellow on account of the peroxide of iron which it contains. Water,
alcohol, oil of turpentine, and the acids, dissolve a small quantity of
it ; it is insoluble in aether ; it separates sulphur, but in so minute
traces, that to perceive them it is requisite to operate on a great
quantity of the matter. The caustic alkalies do not render it green,
either cold or hot. If it be thrown on a filter, it retains a little
water ; and when afterwards dried on a stove, it loses only two-thirds
of its weight. In this state, instead of having a horny appearance,
like glairine, it presents a uniform, friable, solid mass, and does not
swell in water. The water which runs through the filter is as in-
odorous as the substance itself, and it contains a very small quantity
of zo'iodine. When decomposed in a glass tube, it exhales the odour
of burnt horn, and yields gases which strongly restore the blue colour
of reddened litmus. Lastly, glairidine yielded by analysis very evi-
dent traces of iodine, which, as already stated, glairine did not. — Ibid.

ON zo'iodine. by M. BONJEAN.
The author has given this name to a new substance from two
Greek words, expressive of its azotized nature and its violet colour.
In order to obtain it, it is requisite to employ very white glairine,
which cannot be procured except when the sulphurous waters are
in a state of perfect purity, and nearly at their maximum of sulphu-
ration. This substance exists in the state of strongly iridescent scales
of a fine deep violet colour ; it has neither taste nor smell ; it is un-

Meteorological Observations. 79

alterable by the action of light and air, and is insoluble in water.
By concentrated nitric acid it becomes of a yellowish red colour, and
of a rather deeper yellowish red by hydrochloric acid ; concentrated
sulphuric acid renders it of a fine blood-red colour. Oxalic and
phosphoric acids also redden it, but not so strongly as the preceding
acids ; acetic and arsenic acids produce no sensible effect ; and in
all cases diluted acids act almost as powerfully as when concentrated.
Chlorine does not alter it ; alkalies render it of a brown colour,
which the stronger acids bring back to red. Lastly, when heated in
a glass tube, it decomposes without subliming, and leaves a coaly
residue, upon which acids exert no action. During calcination it
yields a smell of burnt horn, and evolves ammoniacal vapours which
restore the blue colour to reddened litmus. — Journ.de Ph. et de Ch.,
Mai 1849.

METEOROLOGICAL OBSERVATIONS FOR MAY 1849.

Chiswick. — May 1. Cloudy. 2. Foggy : overcast. 3. Foggy: fine. 4. Very
fine. 5. Clear and fine : thunder, lightning, rain and hail in afternoon : cloudy
at night. 6. Overcast. 7, 8. Qvercast and cold : fine : cloudy. 9. Fine: showery.
10. Overcast: slight rain. H. Cloudy and cold. 12. Fine: overcast. 13. Very
fine. 14. Rain: fine. 15. Cloudy: fine. 16. Rain : cloudy. 17. Cloudy:
slight rain, 18. Overcast. 19. Cloudy and fine. 20. Rain throughout. 21.
Hazy. 22. Rain: fine. 23. Fine. 24. Very fine : densely overcast at night.
25. Cloudy : very fine. 26. Overcast : very tine. 27. Very fine ; cloudy : rain.
28. Overcast: very heavy rain. 29,30. Very fine. 31. Dry haze : overcast:
clear at night.

Mean temperature of the month 55'''19

Mean temperature of May 1848 58 '12

Mean temperature of May for the last twenty-three years ... 54 -22

Average amount of rain in JMay l*82inch.

Boston. — May 1. Cloudy. 2. Cloudy: rain early a.m. and late p.m. 3 — 5.
Fine. 6 — 9. Cloudy. 10. Rain : rain a.m. and p.m. 11,12. Cloudy. 13,14.
Cloudy: rain p.m. 15. Cloudy. 16. Rain: rain a.m. and p.m. 17. Fine:
rain A.M. and P.M. 18. Rain: rain a.m. and p.m. 19. Cloudy. 20. Rain:
rain A.M. and r.M. 21. Cloudy: rain p.m. 22. Cloudy: rain, with thunder
and lightning P.M. 23. Cloudy : rain p.m. 24. Fine. 25. Rain : rain, with
thunder and lightning early a.m. 26. Fine, 27. Rain : rain early a.m. : rain p.m.
28. Cloudy : rain early A.M. 29. Fine: rain early a.m. .'30,31. Fine.

Applegarlh Manse, Dumfries-shire. — May 1. Remarkably fine day, 2. Dull,
but fair. 3. Fiery heat : dry and parching. 4. P'iery heat. 5, 6. Fiery heat :
heat less. 7. Fiery heat : a few slight drops of rain, 8. Fiery heat. 9. Mild
day : wind variable. 10. Mild day: showe^on the hills. 11. Chill and piercing :
ungenial. 12. Mild and genial : rain at night. 13. Dropping day : most wel-
come rain. 14. Wet morning : bright afternoon. 15. Mild and damp: showers.
16. Heavy showers, 17. Wet morning : very fine and hot, 18. Slight showers :
fine cool evening. 19. Hot forenoon : blowing evening. 20. Heavy showers :
dull. 21,22. Very fine day : damp evening. 23. Showers in forenoon : very
fine. 24. Fair, but dull. 25. Fair and clear : cloudy p.m. 26. Fair and very
fine, 27. Beautiful day. 28. Beautiful day : still warmer. 29. Fine, though
cloudy : showers P.M. 30. Fine : clear bracing weather. 31. Slight rain : wind
high P.M.

Mean temperature of the month 50°*5

Mean temperature of May 1848 52*9

Mean temperature of May for twenty- five years 51 '09

Rain in May for twenty years , 1'69 inch.

Sandwick Manse, Orkney. — May 1. Fine: clear. 2. Cloudy. 3. Clear: fine.
4. Fine. 5. Cloudy : fine. 6. Cloudy : clear. 7. Cloudy : fine. 8. Cloudy.
9. Bright : cloudy. 10. Fine. 11,12. Cloudy. 13. Rain : fine. 14. Fine:
drizzle. 15, 16. Cloudy: drizzle. 17. Cloudy: rain. 18. Drizzle: cloudy.
19. Clear. 20, 21. Cloudy. 22. Cloudy: hazy. 23. Bright: clear. 24. Bright:
rain. 25, 26. Bright : clear. 27. Cloudy : clear. 28. Bright : cloudy. 29.
Cloudy. 30. Bright : clear. 31. Bright : cloudy.

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THE

LONDON, EDINBURGH and DUBLIN

PHILOSOPHICAL MAGAZINE

AND

JOURNAL OF SCIENCE.

[THIRD SERIES.]

AUGUST 1849.

XI. Oti the Lignites and Altered Dolomites of the Island of
Bute. By James Bryce, Jun,^ M.A., F.G.S.*

I. Introduction.

I. npHE only account which we possess of the geology of
A Bute is that given by Dr. MacCulloch in his " De-
scription of the Western Islands of Scotland." During the
thirty years that have elapsed since the publication of that
work, no observations that I am aware of have been put on
record, either supplementary to this account or in correction
of it. Indeed the island seems to have been entirely over-
looked ; the superior grandeur and interest of the sister isle
of Arran having wholly absorbed the attention of geologists.
Yet Bute has many points of great interest in itself; and phae-
nomena which in Arran are but obscurely shown are here
fully exhibited. During a residence in the island for a part
of last summer, I had frequent opportunities of testing the
accuracy of Dr. MacCulloch's account; and it is but justice
to the memory of that distinguished geologist to say, that I
have found the description of the phaenomena to agree very
closely with my own observations; and his work to be, here
as well as in other places, a safe and pleasant guide.

II. Corrections and Supplementary Remarks.

2. The island of Bute is naturally divided into four por-
tions, by three deep depressions or valleys, which traverse it
perpendicularly to its greatest length. These low tracts ter-
minate on either side of the island in deep bays, between
which there can be no doubt, as well from the lowness of the
ground as from the marine character of the materials of which
these tracts are composed, the sea once flowed ; thus forming

* Communicated by the Author.
Phil. Mag. S. 3. Vol. 35. No. 234. Aug. 1849. G

82 Mr. J. Bryce 07i the Lignites and Altered Dolomites

three straits or narrow channels dividing Bute into four
islands. From measurements made by Robert Chambers,
Esq., and given in his beautiful and interesting work on An-
cient Sea-Margins, just published, it appears that these low
tracts are about thirty feet above the present sea-level ; an
elevation very nearly the same as that of the flat region between
Loch Lomond and the Clyde, in which we have the additional
and more satisfactory evidence derived from shelly deposits.

Another interesting feature in the structure of Bute, and
one intimately connected with the origin of the low tracts re-
ferred to above, is the terrace which surrounds almost the
whole island, at the height of between twenty and thirty feet
above high-water mark, and along which the road is conducted
throughout the greater part of the coast. The cliffs, which
in many parts rise above this terrace, are often worn into
caves, and bear other obvious marks of the action of the sea.
This terrace is no doubt the former beach. It is well-marked
along the opposite coast from Gourock to Largs, in the Cum-
brays, in Arran, and on most of the sea-lochs connected with
the great estuary of the Clyde. Taking this along with other
evidence accumulated by Mr. Smith of Jordan Hill in various
papers, we cannot hesitate to admit, that at a comparatively
recent period such a change of level has been effected in Bute
as to convert a detached group of islands separated by narrow
straits, into continuous land.

3. The valleys just described are the boundaries between
dissimilar strata, the line of junction generally keeping the
middle of the valley, but often concealed either by marshy
ground or accumulations of shingle. The northern portion
of the island, between the Kyles on one side and Kaimes and
Ettrick bays on the other, is composed of mica-slate. The
district south of this, bounded by the Rothsay Valley, presents
siliceous and common clay-slate; while the portion extending
from this valley to that of Kilchattan is occupied by red sand-
stone, usually conglomerate; and finally, the southern portion
is composed of various rocks of the trap family erupted through
the sandstone and overlying it. The connexion of these strata
with the mainland is most intimate. The slate and sandstone
are the terminal portions of those great bands of sedimentary
strata which extend from Angus to the Clyde, being parallel
throughout to the granitic axis of the Grampian chain ; while
the erupted rocks in the south of the island are a prolongation
of the great outburst of the igneous formations, which, affect-
ing a general parallelism with the same axis, stretches from
sea to sea in considerable ranges, as the Kilpatrick and Camp-
sie Hills, the Ochills and some minor ridges in the south-east

of the Island of Bute. 83

of Perthshire. The valleys intersecting the island seem ob-
viously a part of that great system of parallel fractures which
run in a north-east and south-west direction on both sides of
the Grampians, and are probably due to the original upheaval
of that chain, and partly to the subsequent eruption of the
igneous rocks just mentioned through the old red sandstone,
and the coal formation which rests upon it.

4. The strata of sandstone are fully exposed on the shore
and in the cliffs from Rothsay to Ascog. South of Bogany
Point limestone appears interstratified with the sandstone, the
two rocks gradually passing into one another at the junction.
Dr. MacCulloch describes one bed — I noticed several others ;
but the beds being thin, of small horizontal extent, and con-
taining generally much siliceous matter, the rock is of little
oeconomical importance in this place. On the north side of
the small rocky promontory south of Ascog Mill thin courses
of nodular limestone traverse beds of brown shale. Subordi-
nate to the sandstone, the shale is of considerable thickness,
and appears again in the high banks above the road.

The south side of the same promontory presents the follow-
ing strata: — The lowest bed is a fine-grained bluish-gray
nodular limestone; it is succeeded by a black bituminous
shale, containing veins of coal less than a quarter of an inch
thick. A bed of concretionary limestone rests on the shale,
the base or paste being a dark-coloured limestone, and the
concretions rounded lumps of the same rock, often of consi-
derable size. The upper part of the cliff is occupied by trap
in various prismatic forms. By the contact of the trap, both
the base itself and the imbedded lumps are so much altered
as very closely to resemble the trap itself. The trap rock
occupies a considerable area inland, and is upwards of 100
feet thick. Dr. MacCulloch has fallen into a slight error
regarding it: he says, " When examined on the shore it ap-
pears rather to pass through the sandstone than to lie over it;
but there is considerable obscurity in this place, as the lateral
junction of the two is concealed by a cavity filled with earth."
The junction is better exposed at present, probably in con-
sequence of the continued action of the sea ; and there can be
no doubt that the relative position of the strata is such as
above described. The trap reposes upon the sandstone, and
does not pass through it.

5. The most considerable mass of limestone in the island
occurs on the south side of Kilchattan Bay. Its characters
are accurately described by Dr. MacCulloch, but he has mis-
taken its position. " This bed seems to lie over all the sand-
stone strata at this place, and to be the rock immediately in

G 2

84 Mr. J. Bryce on the Lignites and Altered Dolomites

contact with the superincumbent trap." A little way above
the limestone quarry, near the ruins of Kelspoke Castle, the
beds of sandstone are distinctly seen dipping towards the trap,
both the dip and inclination being the same as below the lime-
stone ; and it thus appears that the limestone is here, as in
other parts of the island, subordinate to the sandstone, and of
colemporaneous origin.

6. The limestone and shale which are interstratified with
the sandstone in several places, and at Ascog are also accom-
panied by very thin veins of coal, bear a striking resemblance
to true coal measures ; and it is therefore not surprising that
coal has been thought to exist in or under this sandstone, and
that several attempts have been made to discover it. These,
however, have been fruitless, and must always prove so; since
there can be no doubt that the sandstone is the old red, and
therefore inferior to the whole coal formation. The reasons
lor this opinion may be briefly stated.

(1.) Since in the adjoining tracts the series of rocks succes-
sively superimposed on the central granite is complete, and
old red sandstone occupies in these its proper place, we may
fairly infer that the sandstone which in Bute succeeds the
slate series must be the old red. (2.) This sandstone, if con-
tinued on the line of its bearing, would coalesce with that
which forms the Cumbrays, and with that which, rising to the
west from beneath the great mineral basin of Ayrshire, skirts
the coast from Ardrossan to Gourock, and from Toward
Point to Dunoon, and appears again on crossing the Firth,
in Dumbartonshire and Stirlingshire, forming the lower por-
tions of the Kilpatrick and Campsie hills, and thus constituting
a well-marked boundary between the coal basins of Lanark-
shire and the primary ranges of the Highlands. (3.) The
true coal formation associated with carboniferous limestone
exists in Arran, separating distinctly the old red sandstone
from the new. This old red sandstone of Arran incloses beds
of limestone which are similar to those of Bute, and contain
the same fossils as those limestones termed cornstones, which
in England are subordinate to the old red system. Thus the
red sandstone of Bute seems to be identified with the Devo-
nian series of Arran and England. The evidence derived
from fossils is unfortunately not applicable, as I was unable
to find a trace of any organic substance either in the limestone,
sandstone, or shale; and the same statement has been made
by Dr. MacCulloch. It is probable, however, that organic
remains will yet be found on a more extended and careful
search.

of Ihc Island of Bute,

85

III. The Lignite Beds.

7. The trap rocks a(; Ascog derive their chief interest from
being the repository of beds of lignite; a substance so rare in
Scotland, that I believe no well-marked beds occur on the
mainland, and but few in the other islands; and these in
situations very difficult of access. I was led to a careful ex-
amination of this carbonaceous deposit by the statement of
Dr. MacCulloch, that some of the beds occurring here were
unlike any he had seen in his survey of the western islands.

The principal bed is situated in the face of the cliffs above
the road, a little to the south of Ascog Mill, as shown in the
annexed section giving the various beds.

s, sandstone ; r, terrace and road ; ff, greenstone ; a, trap-tuff; b, red
ochre; c, lignite bed; d, pisolitic ochre; e, porphyritic amygdaloid, the
upper portion much-altered.

The lowest bed resting on the sandstone is a small-grained
rudely columnar greenstone; the junction is, however, con-
cealed. Over this is a trap-tufF with a base of greenstone,
and imbedded spherical lumps of the same substance. This
is followed by a bed of red ochre of coarse texture, traversed
by numerous black iron seams, which have doubtless been
produced from a change in the oxidation of the component
iron. Over this is the lignite bed : it is three feet thick, and
consists of hard stony coal, interstratified with a yellowish-
white shale, both being much intermixed with pyrites. The
coal has been so much altered throughout its whole thickness
by the contact of the trap rock, that Mr. Rose of Edinburgh,
to whose examination I submitted the best specimens I could
find, in order that he might determine the species of wood, but
without mentioning the geological situation of the coal, was
"unable to obtain a slice in consequence of the structure being
altered by the contact of a whin dike." The coal has been

86 Mr. J. Bryce on the Lignites and Altered Dolomites

worked to some extent by driving an adit inwards on the line
of the dip, which is about 20° to the westward; but the work-
ings have been for some lime abandoned, and the inner and
lower portions are now full of water.

The floor of the coal has been already described. The
roof is a peculiar rock. It consists of a base or paste of an
ochreous steatite, with imbedded round pieces of the same
substance, and may hence be called a pisolitic ochre; it is S^
yards thick. The bed above this is of the same character ;
but the base feels less unctuous, and with the imbedded stea-
tite it contains also imbedded calcareous spar. The base
effervesces briskly with an acid; and hence we may call the
rock a calcareous amygdaloid. The upper portion of this bed,
to the thickness of a few inches only, is very hard, and has a
semivitreous appearance, and thus closely resembles a por-
phyry. In common with the trap above, and, indeed, all the
beds in this locality, it contains much disseminated iron. The
rest of the cliff" is occupied by greenstone, which is the same
as the lower bed resting on the sandstone.

Another bed of lignite occurs on the opposite, or north-
west side of the trap district, overlooking Ascog Lake. Tl)e
coal dips to the interior of the area, that is, nearly south. It
is of about the same thickness, and is accompanied by beds of
steatite and red ochre, very similar to those above described ;
but the nature of the ground is such that a complete section
cannot be had, and the precise number, therefore, and order
of the beds cannot be exactly stated. The association, how-
ever, of the lignite with ochres and steatites here also is suffi-
ciently distinct, and it is even probable that these beds are
persistent throughout the whole of this district. It is to these
ochreous and steatitic beds that Dr. MacCulloch refers, when
he says that he " has met with no similar substance among the
numerous trap rocks examined in the course of the survey of
the western islands." He has not indeed described any such
strata; yet casual mention is made (vol. i. p. 376) of an iron-
clay and jaspery substance, forming extensive beds in the trap
of the cliffs of Talisker, in Skye — the same in which the lignite
also occurs — and that these are often variegated with red,
gray, and purple colours. No further description is given,
nor is the precise position of the coal mentioned, the cliffs
being very difficult of access.

But even by such a brief notice the steatitic beds and varie-
gated ochres are easily recognised ; and though these charac-
ters are not very distinctly marked in the beds we have been
describing in Bute, yet they apply exactly to the red and va-
riegated ochres, which occur as members of the trap series of

of the Island of Bute. 87

the north-east of Ireland. These rocks attain a much more
complete development than in this country, both geographi-
cally and in relation to the number and variety of the beds.
Tliey extend continuously over an area of upwards of 1000
square miles; and while the thickness is, on an average, about
300 feet, in very many cases it reaches to 1100 or 1200 feet.
The whole series reposes on the chalk formation, while the
corresponding rocks of this country rest upon the old red and
carboniferous systems. Now in this series the lignites occupy
a determinate place ; they occur in the middle region, asso-
ciated with the steatites and variegated ochres, which are
always largely developed wherever the series approaches to
completeness. Instances may be seen at various points in the
cliff's at the Giant's Causeway, at Ballintoy, at Glenarm, and
at numerous places in the interior of the district. Similar
beds are associated with the lignites of Bute and Skye, and
most probably also of others of the Western Isles, though the
notices are too vague to be relied on. We are thus led to
the interesting conclusion, that such association is not acci-
dental, but has been determined by the prevalence, over a
considerable area, of certain similar and fixed conditions,
regulating the succession of the igneous eruptions, the mode
of their consolidation, and the periods of repose during which
the productions of the adjoining dry land were swept down
and entombed.

IV. Altered Dolomites.

8. The dikes of Bute are composed of greenstone or basalt,
and are extremely numerous. They traverse the different
strata in every possible direction, and are well seen upon the
rocky parts of the coast. All the usual phaenomena are re-
markably well exhibited by them, and can be studied together
in a small space. Crystals of quartz and other substances are
developed in the shale beds near the contact. The dikes can
in some instances be traced continuously for several miles,
preserving the same direction, and the same width — two or
more are sometimes seen to meet and coalesce for some di-
stance and again to separate — a narrow dike branches off into
several filaments, which unite again — portions of the rock
which is traversed are frequently found entangled in the dike;
and these, as well as the contiguous strata, present the usual
alterations now universally acknowledged to be the result of
igneous action.

A remarkable change is produced on the Kilchattan lime-
stone by one of these dikes. Its direction is very nearly the
same as the dip of the limestone, and the effects are well seen at

88 Mr. J. Bryce on the Lignites and Altered Dolomites

the eastern side of the quarry. Along the plane of contact with
the dike the limestone is altered to the state of a granularsac-
charine marble, which on the application of a slight pressure
crumbles into a fine powder. This is succeeded by a hard
crystalline marble, the crystals appearing in distinct flakes.
Between this and the first change, which is one of simple in-
duration, there are many gradations. Similar effects are
common at the contact of limestone with plutonic rocks; in
some localities they are accompanied by other singular changes
of a chemical nature. Magnesia, and sometimes silica and
alumina, are introduced into the composition of the limestone,
so that simple carbonate of lime becomes a double carbonate
of lime and magnesia. The question whence this magnesia
has been derived has occasioned much difference of opinion
among geologists. Some imagine that it has been transferred
from the plutonic rock to the limestone; while others hold
that, as fractures and dislocations of the earth's crust accom-
panied the eruption of these plutonic rocks, gaseous exhala-
tions might find their way from beneath, and introduce car-
bonate of magnesia and other substances into rocks near the
surface. In confirmation of this view, Mr. Phillips has shown
in his Geology of Yorkshire, that "common limestone is do-
lomitized by the sides of faults and mineral veins far away
from igneous rocks of any kind;" and some distinguished
chemists have expressed their belief that carbonate of mag-
nesia may be sublimed by the action of great heat. (Rep.
Brit. Assoc, for 1835, Trans. Sect. p. 51 ; Phillips's Geology,
vol. ii. p. 98.) Much doubt, however, still hangs about this
subject. Cases occur in which magnesia has been introduced,
although the limestone could not have been subject to such a
pressure as would confine its carbonic acid when the rock
was softened by heat.

Being anxious to elucidate, if possible, this obscure subject,
1 submitted two specimens of the rock to Mr. John Mac-
adam, lecturer on chemistry in this city, for examination with
reference to the presence or absence of magnesia. The fol-
lowing is Mr. Macadam's report; the specimen referred to
as No. 1 is the saccharine marble from contact with the
dike ; No. 2 is the unaltered limestone — both were average
specimens.

" I have carefully subjected to chemical analysis the spe-
cimen of limestone No. 1, with special reference to the pre-
sence or absence of magnesia; and I find from the indications
given, that carbonate of magnesia constitutes about 2| per
cent, of the whole mass. The mineral is not, therefore, a
double carbonate of lime and magnesia. Its other and prin-

of the Island of Bute. 89

cipal ingredients are carbonic acid and lime, besides which
silica is present, as also traces of oxide of iron and alumina.

" In the specimen No. 2 I find magnesia in great abun-
dance, the amount present being equivalent to 33-72 per cent,
of carbonate of magnesia. The other constituents present are
similar to those reported in No. 1. From the large propor-
tions of carbonate of lime and carbonate of magnesia present
in specimen No. 2, it would appear to be a species of dolo-
mite. It may be noticed that the physical characters of No. 2
are very different from those of No. 1 ; the former is difficult
to pulverize, the latter is extremely susceptible of division.

"The action of strong hydrochloric acid on both specimens
causes a portion of gelatinous silica to appear, showing the
presence of a silicate, which may be that of magnesia, since
the quantity of gelatinous silica is about sufficient to combine
with the r28 per cent, of caustic magnesia existing in the
specimen No. 1. There is a less quantity of this gelatinous
silica in No. 2. The greater portion, however, of the silica
present in both specimens remains undissolved in the gritty
or pulverulent condition, and is hence in a state of mere me-
chanical mixture with the other constituents of the limestone.
It would require a minute quantitative analysis to determine
whether the 1*28 per cent, of magnesia exists as a carbonate
or silicate, or partly as both."

The phaenomena are thus of a contrary character to what
I had anticipated; the unaltered rock is a dolomite, and con-
tains nearly 34- per cent, of carbonate of magnesia, while the
altered rock contains less than 3 per cent. What has become
of the constituent magnesia? Has it been driven off by the
heat to which the limestone was exposed ? Most chemists are
unwilling to admit that this is possible ; and it may reasonably
be objected, that if the limestone had been exposed to so high
a temperature as to vaporize its magnesia, the silica would not
be mechanically present, but would have entered into chemical
combination with the lime or the magnesia, and have formed
a silicate.

That whin dikes have sometimes been the means of pro-
ducing such a combination has been shown by an eminent
chemist. In a valuable paper by Dr. Apjohn on the Dolo-
mites of Ireland, published in the Dublin Geological Journal,
vol. i., the details of an analysis of the white chalk of An-
trim, altered to the state of a saccharine marble, are given
(p. 376); and it is remarked in conclusion, that "the stone
under consideration consists of silica, combined with the mixed
oxides of calcium, magnesium and iron (the carbonate of
lime being mechanically present), and is therefore a mixture

90 Mr. J, Bryce on the Lignites and Altered Dolomites

of trisilicates, very analogous in its composition to olivine.
We are tlius enabled to understand why olivine should be so
very frequently found in trap rocks, and to refer its origin to
the contact of silex at a high temperature with an excess of
the basic oxides ; and we have in some degree a demonstra-
tion that the dolomites which contain siliceous sand could not
have been exposed at any time to a heat sufficiently high to
account for the introduction into them of magnesia in the
vaporous state; for by such a heat a silicate of lime or mag-
nesia, or of both, would have been produced."

The presence of these silicates in both our specimens is
shown by the gelatinous silica appearing ; yet a greater quan-
tity of silica is present mechanically, which, as already stated,
seems inconsistent with the exposure of the rock to intense
heat; unless, indeed, we could suppose that the silica has been
introduced by infiltration, or the magnesia removed by the
solvent power of free carbonic acid at a period subsequent to
the consolidation of the dike from a state of igneous fusion.
But it is needless to pursue the subject further with our pre-
sent limited knowledge of facts.

Postscript. — Altered Dolomites.

The preceding account was drawn up some months ago for
insertion in the Philosophical Magazine. On consideration,
however, it was thought best to withhold it until careful quan-
titative analyses of the limestones should be obtained. This
has now been accomplished through the kindness of Dr. Ro-
bert D. Thomson, of Glasgow University, of whose skill and
competence it would be presumption in me to speak. It is
hoped that these will afford definite terms of comparison with
other analyses, such as those of Dr. Apjohn already referred
to; and that their publication may lead to the formation of
clearer views respecting an obscure question in theoretical
geology.

The analyses kindly furnished me by Dr. Robert D. Thom-
son are as follows : —

Specimen No. 1 is the saccharine marble from contact with
the dike at Kilchattan, — in the highest state of alteration.

No. 2 is the hard crystalline marble, having the crystals in
distinct flakes, more remote and less altered than No. 1.

No. 3 is the unaltered limestone from the middle of the
quarry, remote from the dike, — an average specimen.

No. 4 is the altered limestone from contact with the over-
lying trap at Ascog Mill ; it is an impure dark-coloured rock
of an earthy aspect, and very like the trap which rests upon it.

of the Island of Bute. ^ I

No. 1. Spec. grav. 2*7 10.

By Ml. J. H. Turnbull. By Mr. Henry S. Thomson^

Silica

Aluiiiiiia

Protoxide of iron . .
Carbonate of lime .
Carbonate of magnesia

6-91

1-68
9065
1-00

IOO-2'I.

I.
5-16
1-50

No. 2. Spec. grav. 2-570.

Silica

Alumina

Protoxide of iron
Carbonate of lime .
Carbonate of magnesia

}

5-70

1-28

91-08

1-17

99-23

I.

II.

1-94.

0-28

0-28

0-52

...

0-56

96-4.8

98-76

96-58

l-'i3

...

2-24?

10017

99-66

No. 3. Spec. grav. 2-679.

Silica

Alumina ....
Protoxide of iron .
Carbonate of lime . .
Carbonate of magnesia
Water, coaly matter and
carbonic acid . . .

}
}

I.

9-70

1-12
67-42
17-31

4-45
100-00

No. 4.

}

64-21

II.

72-12

9-08

1-12
67-00
18-06

4-74
100-00

64-46

Silica

Alumina ....
Protoxide of iron . . .
Carbonate of lime . . .
Carbonate of magnesia
Water and carbonic acid .

100-00 100-00

The silica present is in a state of mechanical mixture.

These analyses are confirmatory of the main points of the
views already stated, and seem clearly to establish the new
and remarkable fact, that by the igneous action in these in-
stances the magnesia has been driven off from the limestone.

6-42

6-60

24-00

21-20

4-62

2-85

1-75

4-89

92 Prof. J. D. Forbes on an Instrument for measuring

The unaltered rock is a dolomite containing nearly 70 pef
cent, of carbonate of lime, and nearly 20 per cent, of carbonate
of magnesia ; while the altered rock contains but from 1 to 2
per cent, of the latter ingredient. To what cause are we to
assign the changes that have taken place ? Has the magnesia
been sublimed by heat? or has it been withdrawn by the sol-
vent power of free carbonic acid ? On the nature of these
and the other chemical changes that have been induced, I do
not feel myself competent to express an opinion ; and from
such limited premises it would be unphilosophical to draw
any general conclusions. The subject is one, however, of
great interest both to the geologist and chemist, as the facts
are directly opposed to the received views* ; and as no instance
of similar changes on dolomitic rocks has, so far as I am aware,
ever been put on record.

High School of Glasgow,
June 1849.

XII. Notices. By Prof. J. D. Forbes f.

1, On an Instrument for measuring the Extensibility of Elastic

Solids.

THIS instrument is almost a faithful reproduction of
S'Gravesande's apparatus described in his Physices Ele-
menta Mathematical 1742 (but not in the previous editions).
It is described or alluded to by few modern writers, except
Biot in his Traite de Physique. It consists of a strong
wooden table or frame, with a vice at each end, between which
a wire or lamina may be stretched with a determinate tension
by means of a weight attached by a cord, passing over a pulley
in the manner of the musical apparatus called a monochord.
After the tension is adjusted both vices are screwed fast, the
space included between them being exactly fifty inches. If,
now, any deviation of the middle point of the wire included by
the vices be made (similar to the action of sounding a harp-
string), the force required to pull it a certain distance aside
will depend, — 1st, on the length of the wire; 2nd, on its ten-
sion; 3rd, on its extensibility, or the modulus of elasticity.

S'Gravesande employed his apparatus to verify Hooke's
law, that the extension is as the extending force within the

* For the latest and best account of the views of geologists on this sub-
ject see the well-known work of Dr, Daubeny on Volcanos, 2ncl edit., re-
cently published ; also an admirable resume in the eloquent address of
Prof. Oldham of Dublin University, which has just appeared.

t From the Proceedings of the Royal Society of Edinburgh.

the Extensibility of Elastic Solids. dS

limits of perfect elasticity. But it does not seem to have oc-
curred to him, nor (singularly enough) to later experimenters,
to deduce from the forces required to produce given devia-
tions, the specific extensibility, or what Dr. Young calls the
viodiilus of elasticity of the body.

It is essential that the deviation from the rectilinear position
of the wire should be ascertained with great nicety, and
S'Gravesande's contrivance effects this in a very neat and
satisfactory way. A fine steel chain attaches by a hook to
the middle point of the extended wire, the other end being
secured to the circumference of a nicely-centred wheel. An-
other chain attached similarly to the wire of the same wheel
has a scale attached to it, a weight placed in which causes the
wheel to revolve, and by means of the first chain and hook
pulls the wire out of the straight line. A long index fixed to
the same axis with the wheel points out the deviation on a
much-magnified scale, referred to a divided semicircle of brass.
Thus a weight being placed in the scale, the corresponding
deviation is instantly shown.

Let P be the weight in the scale, D the deviation of the
wire, s = halfxhe length of the wire between the vices ; it was
proved in this communication that

p=.tP.m(^)'.

where M is the modulus of elasticity, measured in grains, which
is easily reduced to the equivalent length of a similar wire or
lamina, according to Dr. Young's definition. This is on the
supposition that Hooke's law of elasticity (the extension is as
the extending force) is correct; and that law is verified if the

term M( — 1 be found for the same wire practically to vary

as the cube of the deviation. The value of M, the modulus,
is also at once given by a single observed deviation, the ten-
sion being known.

A small correction in the value of P is to be made for the
weight of the wire deflecting it from a straight line. This
small correction had not escaped the notice of S'Gravesande
when he verified Hooke's law.

Example. A steel pianoforte wire, tension 50,000 grains
= T; 5=25 inches.

Values of D. Values of P. 2T 5. mC-V.

•25 inch 1100 grains 1000 100
•50 ... 2720 ... 2000 720
•75 ... 5400 ... 3000 2400

V3 =S9,

94- On the Refractive and Dispersive Power of Chloroform.

The numbers in the last column should vary as the cubes
of those in the first, or be as 1, 8, 27. It we deduct 10 grains
from each of them for the action of the weight of the wire
depressing it, we shall have these numbers —

90 710 2390;

dividing respectively by 1, 8, and 27, —

90 89 88-5.

Hence the mean result for Mf — j , for D = '25, or — = y^^,

is nearly 89 grains, consequently,

M
(100)^
and M = 89,000,000 grains.

But a foot in length of the wire in question weighs 1 1 grains.
The equivalent modulus of elasticity is therefore very nearly
8,000,000 feet of the wire in question, which agrees closely
with the received numbers for steel wire.

2. Note respecting the Refractive and Dispersive Poisoer of
Chloroform.

From an experiment made in very cloudy weather, and
therefore rather unfavourable light, I determined the following
indices of refraction for pure chloroform, prepared by Dr.
George Wilson, ofsp. gr. 1*4966.

The measure of the refracting angle of the prism was 39°
■tl'. References were made to the principal lines of the spec-
trum, as below : the temperature of the fluid was probably 54-°.

Extreme red j«,= l'44'75

B (in the red) . 1*4488

D (in the orange-yellow) 1*451

b (in the green) 1*456

F (in the blue) 1*457

H (in the violet, being the least refran-"! 1.4,63

gible of the two groups so designated) J^

Extreme violet 1*4675

Hence the refractive index is by no means remarkably great,
being nearly that of wax, spermaceti, and several of the essen-
tial oils.

The dispersive power, or — ^j is equal to '045, which again

agrees nearly with that of the essential oils. The high specific
gravity of the body appears to have no marked influence in
increasing its action on light.

On an Experiment to determine the Earth* s density. 95

3. Note regarding an Experiment suggested by Professor
Robison.

In his memoir of Dr. Chalmers, lately read to this Society,
Mr. Ramsay has referred to an experiment which Dr. Chal-
mers was anxious to have performed on the tide-wave in the
Bay of Fundy. The object was to determine the earth's den-
sity by the attraction of the tide-wave on a plummet or spirit-
level, on the same principle as Maskelyne's experiment on
Schiehallion, but with the superior advantages arising from
the perfect homogeneity of the attracting mass, and from the
circumstance that all the observations might be made at a
single station. The experiment might, in short, appear to
unite the advantages both of Maskelyne's and Cavendish's
methods of determining the earth's density.

The suggestion was Dr. Robison's, and Dr. Chalmers had
it from him. It is contained in the Elements of Mechanical
Philosophy, edit. 1804, page 339, and is given in the follow-
ing words : — " Perhaps a very sensible effect might be ob-
served at Annapolis- Royal in Nova Scotia, from the vast ad-
dition of matter brought on the coast twice every day by the
tides. The water rises there above 100 feet at spring-tide.
If a leaden pipe a few hundred feet long were laid on the level
beach at right angles with the coast, and a glass pipe set up-
right at each end, and the whole filled with water, the water
will rise at the outer end, and sink at the end next the land
as the tide rises. Such an alternate change of level would
give the most satisfactory evidence. Perhaps the effect might
be sensible on a very long plummet, or even a nice spirit-
level."

It is needless to observe that the methods proposed by
Dr. Robison are not the best which might be suggested ; but
that, in consequence of the extreme simplicity of the observa-
tion, considered as a purely astronomical one, a deviation of
the direction of gravity of only a very few seconds could be
ascertained within small limits of error*.

I thought it worth while to make the calculation approxi-
mately for an assumed height of the tide-wave. Had the
result been at all encouraging, I should have taken pains to
ascertain, on good authority, the exact rise of the tide, and
the circumstances of the locality whence the rise is greatest.

* The micrometric observation of a plumb-line, as in a zenith sector,
would be sufficient ; or, as Professor Smyth has suggested to me, the view
of the wires of a transit-instrument, with a collimating eye-piece, as re-
flected in a mercury trough, — an observation, the accuracy of which may,
he states, be brought within one-twentieth of a second.

96 Mr. E. C. Summers on a Simple Apparatus

I have calculated the horizontal attraction of a semicylinder
of water 100 feet thick, and of about two, four, and eight miles
radius upon a point at the extremity of the axis of such a se-
micylinder; because these conditions can easily be reduced to
calculation, and because they represent very approximately
the circumstances of an attracted point placed at high water-
mark on a vertical sea-wall facing a basin or estuary. The
radius of the attracting mass of water being represented (more
accurately) by 10,000, 20,000, and 40,000 feet, I find the
influence of a tide-wave 100 feet thick upon a plumb-line to
produce a deviation of only 0"'44 (forty-four hundredths of a
second), 0"*50, and 0"'53; the effect increasing extremely
slowly with the radius, as might be expected. ^If the tide rose
only fifty feet, the first effect would be reduced to 0"*246.

Even the greatest of these calculated deviations affords no
ground for hoping that the method of Robison could be ap-
plied with any success to determine the earth's density.

It is rather singular that this ingenious suggestion is not
once alluded to, so far as I am aware, by any writer on the
figure and density of the earth ; yet surely it was as worthy
of notice as Dr. Hutton's proposal to measure the attraction
of an Egyptian pyramid. (Phil. Trans. 1821.)

XIII. On a Simple Apparatus for Washing Precipitates.
By Eustace C. Summers*.

MY attention has been lately drawn to an account by M.
Bloch, given in the May Number of the Annales de
Chimie et de Physique^ vol. xxvi. p. 126, 3rd series, of a new
method of washing precipitates by means of a self-regulating
siphon. The instrument proposed by M. Bloch is, however,
open to several serious objections. In the first place, as soon
as the requisite quantity of water has been supplied to the
filter, the water rises in" the exterior air-tube to the level of
the liquid in the vessel from which the supply is obtained.
Now if the precipitate be very light, part of// also is liable to
gain access to the tube and adhere to its sides. Again, when
the level of the water in the filter falls, the column of water
in the air-tube does not always fall so as to leave free access
to the air. On the contrary, the whole or part of it is fre-
quendy carried upwards by the pressure of the air, and falls,
not into the filter, but into the reservoir; and should any of
the precipitate be carried with it, which is far from improbable,
of course an analysis might be at once invalidated. I say

* Communicated by the Author.

for Washing Precipitales.

97

nothing of the difficulty, which, however, is by no means
slight, of bending the two concentric tubes; because all the
advantages, together with greater convenience for washing,
&c., may be obtained by having the tubes entirely distinct.

The apparatus of M. Gay-Lussac, as described in Mohr
and Redwood's Pharmacy, is far superior to that now proposed
by M. Bloch, inasmuch as the air-tube does not communicate
with the fluid in the filter. The following contrivance has,
however, occurred to me as furnishing the most simple and
effectual way of attaining the object in view, and has the ad-
vantage of being applicable upon any scale of magnitude.

It consists of a reservoir, fig. a, having the mouth placed at
its base. This, when
the vessel is filled with
water, is closed by a
cork, pierced by a
straight tube ^, pass-
ing through it ob-
liquely downwards.
It is now obvious that
the water will rise in
the tube b so long as
air can gain access to
the interior of the re-
servoir ; which, how-
ever, is prevented
when the water in the
tube is sufficiently
high to cover the
whole of its lower ex-
tremity. A siphon is then introduced through this tube so
as to project into the reservoir slightly beyond the lower ex-
tremity of the tube, care being taken to leave sufficient space
to allow of the passage of air between the siphon and the sur-
rounding tube. The funnel is placed beneath the long leg of
the siphon, so that the edge of the filter is a little above the
level of the water in the straight tube. In this condition the
apparatus works. As long as the level of the water in the
filter is lower than the level of that in the tube b, the column of
water ce will be heavier than the column cd, and consequent!}'
the siphon will keep up a supply of water, bubbles of air ob-
taining access to the interior of the reservoir, as the level of
the water in the tube b is reduced by the action of the siphon.
But no sooner does the water in the filter attain the same
level with that in the tube, than the column of water cd is
equal in pressure to the column ce, and consequently the action

Phil. Mas. S. 3. Vol. 35. No. 234. Au". \s\-9. ' H

98 Dr. Beke on the Sources of the Nile.

of the siphon is slopped, the water in the tube b remaining
at just sufficient height to excUide the air from the interior of
the reservoir.

This simple apparatus may be affixed to am/ convenient
vessel having an aperture at the bottom ; all other openings
being of course closed, so as to prevent the ingress of air ex-
cept by the tube b. A common salt glaze earthenware wash-
ing-bottle, or a Griffin's gas-holder, will be found to answer
the purpose perfectly.

Glasgow College Laboratory,
July 6, 1849.

XIV. 0?i the Sources of' the Nile ; being an attempt to assign
the limits of the Basin of that River. By Charles T. Beke,
Esq., Ph.b, F.S.A. Sfc*

IN treating of the sources of the Nile, it is not intended to
regard any particular source or spring as being more
especially and exclusively the true head of that river. It will
not even be discussed whether this or that large branch of the
river should be considered to be the principal one. Such ques-
tions at the outset are not likely to lead to any satisfactory
result. Our object must be in the first place to determine the
entire limits of the basin of the river ; we have next to ascer-
tain what principal arms unite to form the main stream ; we
must then trace to their heads the several smaller streams
which form those branches ; and when we have succeeded in all
these points, we shall then — but not before — be competent to
decide which of these numerous ramifications has the fairest
claim to be regarded as the true source of the Nile.

It may however be objected, and not without a show of
reason, that though this is the theoretical method of investi-
gating the subject, yet the question is susceptible of a more
practical solution; — that, as in the case of most other rivers,
there is some particular stream which by common consent is
looked on as the soicrce of the Nile, and this without regard to
its being actually the head of the longest or the largest branch.
Were this really the case, we should in one sense be bound
to acquiesce in the recognition of such a source, even though
it might not possess all the attributes of the true head of
the river. But the fact is not so. The Abai, the river
of Abessinia, whose source was visited and described by
the Portuguese Jesuits in the beginning of the seventeenth

• Communicated bv the Syro-Egyptian Society of London, having been
read before that Society on the 9th of January 1849.

Dr. Beke on the Sources of the Nile. 99

century, and 150 years later by Bruce, is (as I know from
personal experience) undoubtedly considered by the modern
Abessinians to be the Nile. But among the ancient Abessi-
nians, (or more properly speaking the Axomites of Northern
Abessinia, who were known to the civilized world in the first
ages of the Christian aera,) it was the Takkazie, and not the
Abai, which was regarded as the Nile. Of this a direct proof
is given in the second Adulitic inscription, which, recording
the victories of one of the princes of that country, says : —
" After this, I reduced Ava and Tziamo, Gambela and the
counlr}' round it, Zingabene, Angabe, Tiama, and the A'diagai,
Kalaa, and Semene^ a 7iation beyond the Nile, among moun-
tains difficult of access and covered with snow ; in all this
region there is hail and frost, and snow so deep that the
troops sunk up to their knees. I passed the river, and sub-
dued them:" — in which passage it is manifest that refer-
ence is made to the well-known province of Samien beyond
the Takkazie, in which province are the loftiest mountains
of Abessinia topped with snow, or more properly speaking,
a light kind of hail*. It is not unimportant to the present
question to remark that in the ancient Ethiopic language,
the word Takkazie is not a proper name, but an appellative
signifying river in general; so that " the Takkazie" is simply
" the river;" and it is in this sense that in the Ethiopic Scrip-
tures it is said that the waters of the Takkazie were turned by
Moses into blood.

But the question of superiority is far from lying between
these two rivers, the Takkazie and Abai, alone. Proceeding
further southwards up the direct stream of the Bahr el Abyad
or White River, we come, in al)out 9° N. lat., to another large
arm named Sobat, Telfi, or River of Habesh, which in its upper
course is called Bako, then Uma, and afterwards Godjeb. The
source of the Godjeb is in KafFa, where it is revered by the
natives as the head of the Nile. Nevertheless there is no
more real ground for such a preference of the Godjeb than
there exists in the case of the two other rivers already men-
tioned. The recent expeditions sent by Mohammed Ali, Pasha
of Egypt, to explore the Nile, have ascended the White River

* " Snow i? very rare in Abessinia; it is seen on days when the clouds
are but little raised above the earth, and are at the same time widely ex-
tended. The flakes are small, triangular, and radiated.

"Hailstones which fall at an altitude of 4650 to 4700 metres [15,500 to
15,600 English feet] have the form ofa truncated polyedric pyramid, hollow-
The edges of the pyramid are granulated. This hail is almost as light as
ed at the base and summit ; the hollow being in the form ofa reversed cone,
snow. " — Letter from M. Schimper, on the Meteorology of Abessinia, in the
Coviples Rendus, vol. xxvi. No. 7- (Feb. 14, 1848 , p. 229.

H2

100 Dr. Beke on the Sources of the Nile.

as far as the country of Barl in 4° N. lat., 500 miles above
the confluence of the Sobat or River of Habesh ; and still
the head of the Nile is there said to be distant a month's
journey further to the south.

In the absence, then, of unanimity among the people of the
countries watered by the several branches of the Nile, who each
regard, not unnaturally, their own particular river as the prin-
cipal stream ; it is manifest that the question is an open one,
and that its solution must be attempted on general and scien-
tific principles.

When we trace the course of a river, from its mouth up-
wards, to the furthest extremity of each of its several tributaries,
we arrive ultin)ately at a point where the waters no longer
flow towards that river, but take their course in the opposite
direction. This is called in Latin divortia aquarum — the
parting (or flowing in contrary directions) of the waters — and
in German die Wasserscheide, which means the same. Englisfi
geographers have of late years adopted, through the geologists,
the expression watershed, which is evidently a mere corruption
of the German Wasserscheide, and was probably first brought
into use among us by miners from Germany. But such an
expression is objectionable; as to the mere English scholar it
would seem to be a native compound of the words iscater and
shed, and hence might give rise to the idea of a river's basin
being intended rather than the division between two adjoining
basins. The word waterparting is far preferable. For it is a
literal English translation of the Latin divortia aqtiarum and
of the German Wasserscheide ; it expresses the true sense, and
it is not susceptible of ambiguity.

The waterparting between the basins of two rivers is not
necessarily coincident with a mountain -chain, or identical
with it. On the contrary, we have instances of a river's pass-
ing through a mountain-chain, and taking its rise in an ex-
tensive elevated plain, so level in appearance as to render it
difficult, at first sight, to determine in which direction the
waters flow, or ought to flow. But though the waterparting
may not be identical with an abnormal elevation, such as a
mountain-chain, it must, in the nature of things, be the great-
est normal elevation : it must be that point — or rather that line
or series of points — at which the waters from the heavens, no
longer continuing to find a passage in the one direction, seek
it in another. Thus the waterparting forms the extreme
limits of the basin of a river, and the boundary-line between
the several distinct hydrographical systems of which a conti-
nent is composed.

The sources of the Nile, then, are all those head- streams

Dr. Beke o« the Sources of the Nile. 101

which rise along the extreme limits of the basin of that river,
at the waterpartiiig between it and the conterminous basins of
other African rivers flowing towards the Red Sea, the Indian
Ocean, the Atlantic and the Mediterranean respectively, or
possessing (as is the case with some rivers of Asia and America,
and even of Africa) separate inland hydrographical systems
unconnected with the ocean. It is in this sense that I propose
to treat of the sources of the Nile.

Commencing at the isthmus of Suez, and proceeding south-
wards to about the 1 6th parallel of north latitude, we find a
tract of desert country lying between the Nile and the Red
Sea, and presenting no point of very great elevation. As,
however, we approach the parallel of 16° N. lat., the land
rises considerably, and forms the plateau or table-land of
Abessinia. It is only of late years that the true character of
this elevated region has been determined. Formerly it was
generally considered that Abessinia consisted of a succession
of terraces rising one above the other, the lowest being toward
the Red Sea and the highest being in Enarea, where the water-
parting between the Nile and the rivers having their courses
towards the Indian Ocean was supposed to exist. Recent
explorations have, however, determined that this opinion is
erroneous. Instead of the country's rising in terraces as it
recedes from the coast, its summit or culminating line is toward
the coast itself, whence the land falls gradually towards the
interior. This is best shown in the two sections of Abessinia,
the one being from north to south and the other from east to
west, published in the fourteenth volume of the Journal of
the Royal Geographical Society of London.

In the beginning of the year 1841 I explored the water-
parting from Ankobar, the capital of Shoa, northwards about
forty miles, as far as Gedem; and in the printed account of
this excursion* I remarked, that "as the longitude of the
waterparting in that direction [about 40° E. long.] corresponds
very nearly with that of the waterparting in Northern Abes-
sinia, it may perhaps be not unreasonable to infer that they
are both formed by a continuation of the same central high
land." This was before I was aware of the results of Dr.
Riippell's labours, and before I had carried my own series of
levels further across the country to the west of Ankobar. The
comparison of these has not only proved the correctness of
my surmise, but, combined with the personal explorations of
Dr. Krapf and M. Lefebvre along the waterparting between
Shoa and Tigre, and with what we know, though only more
indefinitely, of its continuation to the south of Abessinia, it
• Journal of the Royal Geographical Society, vol. xii. p. 99.

102 Dr. Beke on the Sources of the Nile.

enables us to arrive at tolerably satisfactory conclusions re-
specting the general character of the table-land of Eastern
Africa.

As a whole, this table-land may be described as a succession
of undulating plains, declining very gradually towards the
west and north-west, irregularly studded with loftier mountain-
masses, and intersected by numerous streams; which streams,
after a short course on the level of the plateau, fall abruptly
into deep-cut valleys, in which they soon attain a depression of
from 3000 to 4000 feet below the general level of the table-land.
The valleys of the larger streams, though at first mere fissures
in the rocks, soon open to a considerable width : that of the
Abai, in the south of the peninsula of Godjam, is at least
twenty-five miles from the extreme points where it breaks
from the table-land on either side. And, as the country within
these valleys is exceedingly wild and irregular, possessing all
the characters of a mountainous one ; nothing is easier for a
traveller, who has not first taken a comprehensive view of the
entire region, and who, on crossing a river, finds himself shut
up within a mass of broken country rising around him on all
sides to a relative elevation of 3000 or 4000 feet, or even more,
— than to suppose that, in ascending this broken country on
either side, he is crossing a mountain-chain ; whereas, on
reaching the summit, he has merely arrived on the level of the
table-land.

The fall of the rivers within their deep-cut valleys dimi-
nishes gradually as they flow north-westwards to join the main
stream of the Nile ; which latter, skirting the western flank of
the high land, is the sink into which the Takkazie, the Bahr
el Azrek or Blue River, the Godjeb, Sobat or River of Ha-
besh, the Shoaberri, and whatever other rivers there may be,
are received; its current being very sluggish, and almost
stagnant in the upper part of its course, except during the
floods. In the dry season its bed would indeed almost seem
to consist of a succession of lakes and swamps, rather than to
be the channel of a running stream. At Khartum, at the
confluence of the Blue River with the Nile, the bed of the
united stream is only 1525 feet above the ocean; and it is far
from improbable that even as high up as the 5th parallel of N.
latitude its absolute elevation does not much exceed 2000 feet.

On the seaward or eastern side of the waterparting, the
declivity being much more abrupt and the extent of country
much more limited than on the western side, the rivers must
necessarily be of secondary importance. Thus, proceeding
from the north, we do not meet with a stream deserving of
name till we come to the HawAsh ; and even this river is, near

Dr. Beke on the Sources of the Nile. 103

Aussa, lost in lake Abhebbad before reaching the ocean. The
Doho, Wabbi, or Haines's River, which is the next in succes-
sion, appears in like manner not to have sufficient water to
reach the sea; at least not at all times of the year. Further
to the south, we find the Wabbi-Giw^yna, or Gowin, or Juba
River, possessing a substantive character as an ocean stream ;
but this river, during the dry season, has at its mouth a depth
of only two feet. At a short distance to the south of the
Equator is the Ozi or Maro, which river, though said to be
of great extent, has very little water at the entrance. A short
distance to the south of the Ozi is the Sabaki, which enters
the sea near Melindah, and has a breadth of sixty yards at its
mouth ; but inland it is said to be very much larger. Yet
further to the south, in about 8° S. lat., we find the Lufidgi,
a considerable river, of which the Kwavi, in about 9° S. lat.,
appears to be one of the mouths ; and beyond this, in between
10° and 11° S. lat., is the Livuma, also a large stream.

These rivers of the coast have been enumerated for three
reasons : — 1st. They all of them — as far at least as the Lufidgi
— diminish very considerably in size as they approach the sea j
which is a proof that they have not a sufficient supply of water
to keep their channels open during the dry season : from
which it also follows that the area of their respective basins
cannot be very large. 2nd. They are all said t© rise in the
mountains of Abessiniw, an expression which must be ex-
plained as meaning, not merely the "Abessinia" of Europeans,
but the entire elevated land of Eastern Africa, which is known
to the Arabs by the name of Habesh^ and to the people of
Sennar by that of Makadah. And thirdly, all these rivers are
stated to communicate either with the Nile, or with the great
lake called Nyassi, said to exist in the interior. This last
statement, if not explained, might lead into error; and there
is no doubt that a similar assertion with respect to other rivers
of Africa — especially as regards the alleged union of the Niger
with the Nile — has been the cause of much confusion and mis-
understanding in the hydrography of that continent. What-
ever may be the meaning attached to such an expression
among Europeans, in the native phraseology of Africans it is
merely the enunciation of the fact, that the several sources of
these rivers of the coast are at the waterparting between their
basins and those of the Nile and the streams draining into
Nyassi ; the contiguity of the respective sources being, accord-
ing to the native mode of thinking, equivalent to an actual
water-communication between the streams themselves.

To some persons it may hardly seem possible that such a
mistake should occur. I will therefore give an example from

lO* Dr. Beke on the Sources of the Nile.

my own personal experience. In August 1842, when at the
town of Yaush in Godjam, 1 obtained a good deal of valuable
information respecting the countries lying to the east of the
Abai and to the north of Shoa, from an intelligent Christian
Abessinian merchant named Negaderas* Fanta, who traded
between the market of Baso in Godjam and those of Warra-
hemano and Warrakallu in Eastern Abessinia.

On my inquiring of Fanta as to the course of the Milli and
Berkonna, two rivers of Eastern Abessinia both tributary to
the Hawash, he answered that he knew them well, and that they
joined the Abai. As I was well-aware that this was not and
could not be the case, I began to fear that all the other informa-
tion with which my friend had been supplying me might be of
a similar character. But a little explanation showed me that
he was quite right — that is to say, according to his own laay of
thinking and speaking. On my expressing myself doubtingly
as to the correctness of his assertion, he at once appealed to my'
selfsLS an eye-witness of the fact. " Do you not say (asked he)
that you came to Shoa by the way of the Adal country?" I
admitted that I did. " Consequently you crossed the Hawash,
into which river the Milli and Berkonna flow." This, too, I
could not deny. " The Hawash, after passing between Adal
and Shoa, runs round to the south of the latter country, be-
tween it and Guragie. Does it not ?" As I now began to con-
ceive Fanta's meaning, I did not think it worth while to dispute
the correctness of this assertion ; though 1 knew the fact to be
thatthecourseofthe river in question is/zo/^z and not/o the south.
" Well, then, the Hawash joins the Muger, the confluence of
which river with the Abai you have seen with your own eyes,
if I mistake not." This last was true enough. And so the good
man, Fanta, by merely making the Hawash run the wrong
way, and regarding the Muger as the continuation of it, because
the two rivers have some of their sowces ifi close contiguity on
Mount Saldla, succeeded in demonstrating, to his own if not
to my entire satisfaction, that the Milli joins the Abai ! The
alleged communication between the Kwara or Niger and the
Nile, is doubtless to be understood in a similar manner; the
sources of the eastern arm of the former and those of the west-
ern arm of the latter being at the waterparting between the
respective basins of the two rivers, and thus "communicating
with one another," according to the ordinary African phrase-
ology.

* Negaderas means literally the head (ras) of the merchants (negade), equi-
valent perhaps in its primary application and value to the Console de' Mer-
canti of the Levant — whence our modern title of consul is derived. But
it is now given as a complimentary appellation to most traders of standing.

Dr. Beke on the Sources of the Nile. 105

How far the high table-land of Eastern Africa extends
southwards it is impossible to determine in the existing im-
perfect state of our knowledge on the subject. But it would
seem that we may safely trace its continuation beyond the
Equator. The country of Mono-Moezi, which lies to the
south of 2° S. lat., is described as an elevated plain, the ascent to
which lies chiefly in the territories of the M'sagara and Wohaha
tribes occupying the low lands to the north-west of Zanzibar,
which elevated plain may be regarded as a continuation of the
Abessinian plateau. And, indeed, what knowledge we possess
of the geography of Southern Africa leads to the inference
that the same high land extends along the entire eastern side
of the Continent as far as its southern extremity ; its higher
eastern edge and waterparting being distant from the Indian
Ocean much less than from the South Atlantic, whereby the
rivers all along the eastern coast are far less considerable than
those of the western coast.

We have not the means of deciding how far this great
waterparting of Southern Africa continues to form the boun-
dary of the basin of the Nile. It is manifest, however, that in
proceeding along it from north to south, we must at length
reach a point where the waters on its western side, instead of
continuing to flow northwards into the Nile, take their course
westwards across the Continent. Consequently, beyond this
point the waterparting of Southern Africa is between the hy-
drographical systems of the Indian Ocean and the Southern
Atlantic ; while at the same time a new waterparting comes
into existence between the hydrographical system of the
Southern Atlantic, as represented by the river Congo, and
that of the Mediterranean, as represented by the Nile; which
latter waterparting may, in a general way, be considered to run
from east to west, or perhaps rather from south-east to north-
west.

In the ordinary maps of Africa we find a chain of mountains
laid down as stretching across the Continent from west to east,
between the 7th and 8th parallels of north latitude. This
chain bears the name of the " Mountains of the Moon ;" it
is supposed to be a continuation of the Kong Mountains of
Western Africa, in which the rivers Senegal, Gambia, and
Joliba or Niger, have their sources; and on its northern flank
the sources of the Nile are also supposed to be situated.

The recent Egyptian expeditions to explore the Nile have,
however, demonstrated that such a mountain-chain does not
exist; for they have sailed over the alleged site of these "Moun-
tains of the Moon," and have advanced as far as the country of
Bari, in the 4th parallel of north latitude, without meeting with

106 Dr. Beke on the Sources of the Nile.

any mountains that could lay claim to this title. A detailed
account of the second of these expeditions, being the one which
penetrated the furthest, has recently been published by M.
Ferdinand Werne of Berlin, who took part in it*. The author
states that, according to Lakono, king of Bari, the course
of the river continues thence southwards a distance of thirty
days' journey, as far as the country of Anyan, where it divides
into four small branches. It may not be easy to determine
at what rate this distance of thirty days' journey is to be cal-
culated ; but if we roughly estimate it at twelve miles per
diem (merely as a first approximation), we shall have a di-
stance of 360 miles, or six degrees of latitude ; which distance,
measured from Bari, carries us to two degrees south of the
equator.

This brings us into the country of Mono-Moezi, of which
mention has already been made ; and this (coupled with va-
rious other circumstances which it is unnecessary to enter on
heref) affords not only a plausible derivation of the name of
the " Mountains of the Moon," in which the Nile is, by uni-
versal consent, considered to have its origin, but it serves at
the same time to determine the position of those mountains in
a manner that would seem to be but little, if at all, removed
from the truth.

The " Mountains of the Moon " are an established feature
of African geography. All writers, whether Arabian or
European, mention them ; all travellers in central Africa hear
of them; and yet so indefinite, so various, so contradictory
are the statements respecting these mountains, that nothing
in the least degree satisfactory has been decided about them.
There is however good reason for believing, that all that has
been written and said on the subject of the sources of the Nile
in the Mountains of the Moon, is founded on the statements
of the celebrated astronomer and geographer Claudius Ptole-
maeus of Alexandria, who flourished in the second century of
the Christian aera. One thing is certain, which is, that he is
the first writer by whom the Mountains of the Moon are
mentioned; and it is most probable that he derived his infor-
mation respecting them from the Greek traders o\ Alexandria,
who, from the time of Hippalus's discovery of the monsoons
in the middle of the preceding century, if not previously, fre-
quented the east coast of Africa.

Our only sure method of proceeding seems, then, to be,
that we should refer back to the original statements of Pto-
lemy ; and that, without regarding the numerous commentaries

* Reise zur Enideckung der Quellen des Weissen Nil. 8vo. Berlin, 1848.
f See Edinburgh New Philosophical Journal, vol. xlv. p. 221 et scq.

Dr. Beke on the Sources of the Nile, 107

and glosses upon those statements, we should ourselves exa-
mine and attempt to elucidate them with the help of the ex-
tended geographical knowledge which we possess at the pre-
sent day.

Now, in the 9th chapter of the 4th book of his Geography,
Ptolemy describes the eastern coast of Africa as stretching
"towards the east from Cape Rhaptum on the Barbarian
Gulf, which is also called the Rough Sea on account of the
shoals, as far as Cape Prasum ; beyond which the country is
unknown." And he proceeds to describe Cape Prasum as
being situate in 80° longitude east of Ferro, and 1 5° S. lat. ;
and that "near it, towards the north-east, is an island,
named Menuthius, which lies in 85° E. long, and 12° 30' S.
lat." He adds, that " round the gulf dwell certain cannibal
negroes (^thiopes Anthropophagi), on the west of whose
country are the Mountains (or hill-country) of the Moon —
TO T?79 ^e\rjvq<i 6po<i — the snows of which are received into the
lakes of the Nile." And he describes these Mountains of the
Moon as lying in 12° 30' S. lat.; the one extremity of them
being in 57°, and the other in 67° E. long.

On testing, by means of the information possessed by us
at the present day, the results arrived at by the get)grapher
of Alexandria, we are at once struck with the great extension
in a southerly direction, which Ptolemy has given to the
courses of the Nile and its two great tributary streams, the
Astaboras and Astapus, as likewise to the eastern coast of
Africa, as far as it was then known. For the correction of
this fundamental error our means are two. The one is the
positive knowledge respecting the courses of the rivers them-
selves, which has been acquired from the recent Egyptian
expeditions up the Nile and the explorations of travellers in
Abessinia; the other is the like positive information derived
from the surveys made of the east coast of Africa, and from
the particulars respecting the interior of the Continent col-
lected at various points along the coast.

From the former of these sources of information we are
enabled to lay down, with almost absolute accuracy, the course
of the Astaboras, now known as the Atbara or Takkazie, and
that of the Astapus, Blue River or Abai. From the same
source we further learn that in about 9° N. lat. the main
stream of the Nile divides into three arms; namely — 1st, the
Bahr el Abyad or White River, which has been ascended to
about the 4th parallel of N. lat. ; 2nd, the Sobat, Telfi or
River of Habesh, which falls into the central stream from the
east, and is considered to contribute to the Nile nearly a
moiety of its waters; and 3rd, the Bahr el Ghazal or Keilah,

108 Dr. Beke on the Sources of the Nile.

which joins the Nile from the west, and is described as being
a magnificent stream, with a tolerably rapid current.

It will be observed, however, that by Ptolemy the main
stream of the Nile is laid down as consisting of two principal
arms, the junction of which is placed by him in the second
parallel of north latitude, or nearly seven degrees to the south
of where the junction of the three principal arms actually takes
place. In order to prevent misunderstanding, it is proper to
direct attention to the fact, that I am not alluding here to the
confluence of the Bahr el Abyad and Bahr el Azrek— the
White and Blue Rivers — which are commonly but erroneously
called the White and Blue Niles. This confluence takes place
at Khartum in 15° 37' N. lat. ; and, as it will be plainly seen,
it is merely the junction of the Astapuswith the Nilus. Pto-
lemy's bifurcation of the Nile is, on the contrary, formed by
the union of the Sobat, or River of Habesh, with the White
River, in 9° 20' N. lat., more than six degrees of latitude to
the south of Khartum. It is important to bear this in mind ;
as one of the most fertile sources of error in the consideration
of this subject, has been the regarding of the Blue River, or
" Bruce's Nile" as it is frequently called, as one of the main
arms of Ptolemy's Nile, which it manifestly is not.

Turning now to the east coast of Africa, our first point is
to identify the island of Menuthias; and though the subject
is not altogether free from difficulties, the greatest amount
of probability is certainly in favour of the island of Zan-
zibar. As it is essential to the investigation of the subject
that we should advance from some fixed point, it shall be
assumed that the identity of Zanzibar with Menuthias is esta-
blished. And such being the case, it follows that the Bar-
barian Gulf is the bay or bight in which Zanzibar is situate;
and that the country of the Anthropophagi or cannibals dwell-
ing round this gulf, is that portion of the east coast of Africa
which is opposite to that island. Further, as the Mountains
of the Moon are stated by Ptolemy to lie on the western side
of this country of the Anthropophagi, and in the same latitude
as Menuthias^ we can have no hesitation in placing those
mountains somewhere in that part of the main land which, in
like manner, lies opposite to Zanzibar.

If, now, we apply to these general results the knowledge
which we possess of the physical configuration of the plateau
of Eastern Africa, of which a brief outline has already been
given, we shall perceive that the seaward or eastern edge of
this plateau, when viewed from the lowlands along the shores
of the Indian Ocean, presents the appearance and indeed
possesses the character of an extensive range of lofty moun-

Dr. Beke ow the Sources of the Nile. 109

tains. And that portion of this range which bounds the
country of Mono-Moezi, and which lies in a general direction
to the west or north-west of the island of Zanzibar, corre-
sponds so satisfactorily with the " Mountains of the Moon,"
described by Ptolemy as lying on the western side of the
country of the Anthropophagi who dwelt on the shores of
the Barbarian Gulf near Menuthias, that we may, with every
show of reason, consider the identification as absolute, and
place here the source of Ptolemy's eastern arm of the Nile.

The name Mojio-Moezi itself affords a strong argument in
corroboration of this conclusion. This expression is a com-
pound word, significant in many of the languages of the Kafir
class, which are spoken throughout the entire continent of
Africa south of the Equator, as far as the limits of the Hot-
tentots. The first component of this name, Mono or Mani,
is of frequent occurrence in the designations of countries in
Southern Africa, such as Mani-Congo, Mani-Puto (as the
Portuguese possessions in Africa are called), Mono-Motapa,
&c. ; and its meaning appears to he king or ruler. The second
component, Mo^zi, which alone is properly the name of the
country, has the signification of 7noo?i in the languages and
dialects of the Sawahilis and of the natives of the countries of
Mono-Moezi, Congo, Mozambique, and various others. The
Sawahilis, among whom the word is thus significant, are the
inhabitants of the sea-coast of Zindj, or Zangebar ; and I con-
ceive that the Greeks of Alexandria who traded with that coast,
obtained from these Sawahilis the particulars respecting the
eastern portion of the African continent and the sources of the
Nile, which are recorded by their countryman the geographer
Ptolemy; and that, as it was not an unusual practice among the
Greeks to translate significant proper names into the equiva-
lents in their own language, the designation given by Ptolemy
to the mountains in which those sources are situate — XeXtjvrjii
opo^if " the mountains, or hill country, of the moon " — is simply
a translation of the Sawahili expression, " the Mountains of
Moezi*."

* The discovery of Mount Kilimandjaro, covered with perpetual snow,
recently announced by the Rev. J. Rebmann (see Church Missionary
Intelligencer for May 1849, vol. i. p. 17 et seq.), affords an additional
argument in support of the above hypothesis. Ptolemy states that " the
lakes of the Nile receive the snows of the Mountains of the Moon;" the
upper course of the direct stream of the river has been carried southwards
to about 2° S. lat. and 34° E. long. : and Mount Kilimandjaro, which is
crossed by the road from the coast to the country of Mono-Moezi, is placed
by Mr. Rebmann in 3° 40' S. lat. and 36° E. long. Hence the snow-capped
Kilimandj&ro may be regarded as forming part of the " Mountains of the
Moon (Vloezi)," in which the Nile has its origin.

Mr. Rebmann mentions that the natives have no specific name for snow.

110 Dr. Beke o« the Sources of the Nile.

It is unnecessary to go into further details to show the rea-
sonableness of the opinion that these " Mountains of the
Moon" form the soulh-easterti rather than the southern limits
of the basin of the Nile. As regards the southern limits
themselves, no more can be said, in the existing state of our
knowledge (or want of knowledge) on the subject, than that
they are most probably formed on the east by the basin of the
Lutidji or some other large river flowing into the Indian
Ocean, and on the west by that of the Upper Congo. It must
however not be omitted to be mentioned, that we possess evi-
dence of the existence, somewhere in this direction, of a great
lake, which is very incorrectly shown in the ordinary maps
under the title of Lake Maravi, and which is more correctly
designated Nyassi or "the sea;" an expression apparently
equivalent to the Arabic Bahr, which is used indefinitely to ex-
press a sea, a lake, or a large river, — the "great water," in tact,
of Africans generally ; but whether this "Nyassi" is connected
with the upper course oi' the Nile, or of the Congo, or of the
Lutidji, or whether it possesses a separate hydrographical
system of its own, like the Caspian Sea, we have not for the
present the means of determining. Should the latter happen
to be the case, then it may be the basin of this inland lake,
and not those of rivers flowing in opposite directions into
the Atlantic and Pacific Oceans, which forms the southern
boundary of the river system of the Nile. But however the
case may eventually be found to be, the result will not mate-
rially affect the arguments already used on the subject; and, at
all events, some of the north-eastern arms of the Congo will
still have their sources at the waterparting between them and
the extreme south-western branches of the Nile. It is to be
hoped that Dr. Bialloblotzky, who is on his way to explore
those regions, will be enabled to clear up some of these dark
questions of African geography*.

It only remains for us to consider the western limits of the
basin of the Nile; upon which subject an almost total want of
positive information precludes us from saying much.

According to the information furnished to M. Werne by
Lakono, king of Bari, the direct stream of the Bahr el Abyad,
there called Tubiri, comes from a distance of thirty days'

which they call coldness. But in this there is nothing singular. In the
Arabic and Aniharic languages, bered means cold (coldness) generally,
while bqrad (in Amharic more frequently barado) — which is substantially
the same — means Aaz7 specifically. — July )l, 1849.

* Since this paper was read this traveller lias been compelled to abandon
his undertaking. It must now be left to more favoured explorers to per-
form what was hoped for from him.

Dr. Beke on the Sources of the Nile. Ill

journey to the south. But M. Lafargue, a French traveller
who ascended the Bahr el Abyad in 1845, states that he was
informed that the main stream conies from the west at a di-
stance of only six days' journey south of Bari, It will be seen
that this information is not necessarily opposed to that of M.
Werne, since both arms may well exist; but it shows also that
we are still in ignorance with respect to an extensive and pro-
bably an immense division of the basin of the Nile — namely,
the whole of that portion of it which lies to the west of the
direct stream ascended by the Egyptian expeditions. In the
absence of any certain data, it would be mere speculation to
attempt to fix the waterparting in this direction, except that
we know that it cannot possibly lie much, if anything, beyond
the 20th meridian of east longitude, where the basin of the
Nile must necessarily be limited by that of Lake Tchad.

We will therefore descend the main stream of the White
River northwards as far as 7^ 43' N. lat., where the officers
of the second Egyptian expedition found it to receive three
branches from the south and west. These tributaries were
considered to be of no importance, and to appear to proceed
only from the neighbouring marshes. But they require to be
more closely examined before it can positively be asserted that
they are not streams of some, perhaps even considerable im-
portance. Thence continuing to descend the river, we come
at length, in 9° 20' N. lat., to the great western arm, called
Bahr el Ghazal or Keilah, which has been already described.
The first exploring party was almost in doubt whether this
was not the principal arm of the river ; but as their instruc-
tions from the Pasha were imperative as to their exploring
the direct stream, they did not afford it that attention which
it evidently deserves. M. Lafargue, who subsequently en-
tered the mouth of this river, describes it as a magnificent
stream with a tolerably rapid current.

M. Werne, in speaking of the Bahr el Ghazal, states that
it was described to him as coming y^om Barbary I This our
positive knowledge enables us to assert to be impossible. For
Denham and Clapperton crossed the continent of Africa from
the Mediterranean to Lake Tchad, in about the 15th meridian
of east longitude ; and we know that there does not exist on
their route any watercourse which might be considered as the
upper portion of this river. It would, however, doubtless be
wrong to understand the expression " Barbary " in the sense
in which we usually employ it; as it is not to be imagined that
the inhabitants of the valleys of the Bahr el Abyad and Bahr
el Ghazal have any actual knowledge of that portion of Africa
to which we give this name. We must therefore suppose that,

112 Dr. Beke o?i the Sources of the Nile.

in speaking of the origin of the latter river, they made use
of some expression equivalent to the Arabic Belad d Gharb ;
which, though the name given by Orientals to Barbary, means
literally the wrst country^ Barbary being so called simply because
it lies to the west of them. Under this view of the case, the
statement must be understood to have been, not that this west-
ern arm of the Nile rises in Barbary, but merely that it comes
from some country in the west*.

The fact of the existence of this great western arm, which
is beyond all question, gives rise to serious considerations.
More especially it requires us to re-investigate a statement
made by the historian Herodotus respecting the upper course
of the Nile — a statement which geographers of modern times
have concluded could only be applicable to the Niger, Joliba
or Kwara (Quorra) of Western Africa.

In treating, in his second book, of the origin of the Nile,
the historian says : — " This river flows from the west and the
setting of the sun ; but beyond this no one is able to speak with
certainty, for the rest of the country is desert by reason of the
excessive heat. But I have heard the following account from
certain Cyrenaeans, who say that they went to the oracle of
Ammon, and had a conversation with Etearchus king of the
Ammonians ; and that, among other subjects, they happened
to discourse about the Nile, — that nobody knew its sources :
whereupon Etearchus said, that certain Nasamonians once came
to him ; this nation is Libyan and inhabits the Syrtis, and the
country for no great distance eastward of the Syrtis; and that
when these Nasamonians arrived, and were asked if they could
give any further information touching the deserts of Libya,
they answered, that there were some daring youths amongst
them, sons of powerful men ; and that they, having reached
man's estate, formed many other extravagant plans, and more-
over chose five of their number by lot to explore the deserts
of Libya, to see if they could make any further discovery than

those who had penetrated the furthest That when the

young men deputed by their companions set out, well-furnished
with water and provisions, they passed first through the inha-
bited country; and having traversed this, they came to the
region infested by wild beasts ; and after this they crossed the
desert, making their way towards the west; and when they had
traversed much sandy ground, during a journey of many days,
they at length saw some trees growing in a plain ; and that
they approached and began to gather the fruit that grew on the
trees ; and while they were gathering, some diminutive men,

* Algarve, the southernmost province of the kingdom of Portugal oppo-
site Barbary, derives its name from the Arabic el-Gharb.

Dr. Beke on the Sources of the Nile. 113

less than men of middle stature, came up, and having seized
them carried them away ; and that the Nasamonians did not
at all understand their language, nor those who carried them
off' the language of the Nasamonians. However, they con-
ducted them through vast morasses, and when they had passed
these, they came to a city, in which all the inhabitants were of
tl.e same size as their conductors, and black in colour: and
by the city flowed a great river, running from the 'west to the
east, and that crocodiles were seen in it. Thus far I have
set forth the account of Etearchus the Ammonian ; to which
may be added, as the Cyrenjeans assured me, that he said
the Nasamonians all returned safe to their own country, and
that the men whom they came to were all necromancers.
Etearchus also conjectured that this river, which flows by
their city, is the Nile ; and reason so evinces : for the Nile
flows from Libya, and intersects it in the middle, and (as I
conjecture, inferring things unknown from things known) it

sets out from a point corresponding with the Ister So I

think that the Nile, traversing the whole of Libya, may be
properly compared with the Ister. Such, then, is the ac-
count that I am able to give respecting the Nile*."

The objection usually made to the supposition that this
river of Herodotus is the upper course of the Nile, is, that
the Nasamonians travelled, not southwards but westwards,
and that consequently they could not have reached any river
but the Niger. But, if the historian's expressions are to
be taken as strictly meaning that the road lay throughout in a
westerly direction, it is manifest that it would be just as impos-
sible for the travellers to have arrived at the Niger as to have
reached a western arm of the river of Egypt. In either case,
then, we are bound to suppose that they first proceeded south-
awards — to what distance we cannot say — and then, by con-
tinuing during the last part of their journey in a westerly di-
rection (which is in no wise to be understood as meaning due
west), they may without difficulty have come to the Nile, that
is to say, to the upper course of this great western arm, pos-
sibly at no very great distance to the east or north-east of
Lake Tchad.

The mention of this lake induces me to suggest the proba-
bility that Nyassi and Tchad, the one at the extremity of the
southernmost and the other at the extremity of the western-
most arm of the Nile, are the originals of the two lakes
which Ptolemy describes as receiving the snows of the Moun-
tains of the Moon.

It has merely to be added, that, according to a sketch-map
* Lib. ii. § 31-34; Gary's translation.

VhiU Mag. S. 3. Vol. 35. No. 234^. Aug. 1849. I

114 Mv. Grove on the Effect of

of Darfur, drawn at Cairo in 1841 by Dr. Perron, under the
dictation of Sheikh Mohammed el Tunisi, there is a large
river in the west of that country named Bare ; and that from
the evidence collected by M. Jomard in his Preface to the
Voi/age an Darfour of the Sheikh, it may be concluded that
both that country and Kordofan lie within the basin of the
Nile, and that this river Bare is an affluent of the Bahr el
Ghazal of the Egyptian expeditions.

We have thus brought the limits of the hydrographical
system of the Nile round again to the confines of Nubia and
Egypt ; in which countries, as it is well known, the basin of
that river, on the western as on the eastern side, consists of
little more than the bed of the stream itself.

St. Mildred's Court,
Dec. 30, 1848.

XV. On the Effect of mrrounding Media on Voltaic Ignition.
By W. R. Grove, Esq., M.A., V.P.R.S.*

IN the Philosophical Magazine for December 1845, I
pointed out a striking difference between the heat gene-
rated in a platinum wire by a voltaic current, according as
the wire is immersed in atmospheric air or in hydrogen gas,
and in the Bakerian Lecture for 1847 I have given some fur-
ther experiments on this subject, in which the wire was ignited
in atmospheres of various gases, while a voltameter enclosed
in the circuit yielded an amount of gas in some inverse ratio
to the heat developed in the wire. It was also shown, by a
thermometer placed at a given distance, that the radiated heat
was in a direct ratio with the visible heat.

Although the phaenomenon was apparently abnormal, there
were many known physical agencies by which it might pos-
sibly be explained, such as the different specific heats of the
surrounding media, their different conducting powers for elec-
tricity, or the varying fluency or mobility of their particles
which would carry off the heat by molecular currents with
different degrees of rapidity.

The investigation of these questions will form the subject
of this paper.

An apparatus was arranged, see fig. 1. Two glass tubes A
and B, of 0-3 inch internal diameter and 1-5 inch length, were
closed with corks at each extremity; through the corks the ends
of copper wires penetrated, and joining these were coils of fine

* From the Philosophical Transactions for 1849, part i.; having been
received by the Royal Society August 10, and read December 14, 1848.

surrounding Media on Voltaic Ignition.

115

platinum wire, one-eightieth of an inch diameter and 3*7 inches
long when uncoiled. Tube A was filled with oxygen, tube B
with hydrogen, and the tubes thus prepared were immersed in
two separate vessels, in all respects similar to each other, and
containing each 3 oz. of water. A thermometer was placed in
the water in each vessel ; the copper wires were connected, so
as to form a continued circuit, with a nitric acid battery of eight
cells, each plate exposing eight square inches of surface. Upon
the circuit being completed the wire in the tube containing
oxygen rose to a white heat, while that in the hydrogen was
not visibly ignited ; the temperature of the water, which at
the commencement of the experiment was 60° F. in each
vessel, rose in five minutes in the water surrounding the tube
of hydrogen from 60° to 70°, and in that containing oxygen
from 60'' to 81°*.

Before I enter into a further detail of experiments, I would
remark upon the extraordinary character of this result. The
same current or quantity of electricity passes through two
similar portions of wire immersed in the same quantity of

Fig. 1.

* After the publication of the Bakerian Lecture, my experiment on the
peculiar effect of hydrogen on the ignited wire was noticed in a paper by
M. Matteucci, which though I had it in my hand shortly after its publi-
cation, I regret to say I did not read with the attention it deserved. I have
read it since the experiments in this paper were commenced, and I see that
I am now executing a task assigned to me by my friend. M. Matteucci,
for a different object, makes a somewhat similar experiment to the one
given above, which however differs from mine in the material point, that
he operated first on one gas and then on the other, and thus did not com-
pare the effects produced by the same quantity of electricity. I cannot
quite agree in the conclusions deduced by him from this and the other
experiments he cites, but I will not here contest them, as it would lead me
away from the main point of this paper.

1 2

116 Mr. Grove on the Effect of

liquid, and yet, in consequence of tlieir being surrounded by
a thin envelope of different gases, a large portion of the heat
which is developed in the one portion appears to have been
annihilated in the other. Similar experiments, varying the
gas in one tube while hydrogen was retained in the other,
gave the following results. In five minutes the thermometer
rose —

In the hydrogen. In the associated nitrogen.

1st. From 60° to 69°- 5. From 60° to 81°-5.

In hydrogen. In carbonic acid.

2nd. From 60" to 70°-5. From 60° to 80°.

In hydrogen. In carbonic oxide.

3rd. From 60° to 70°. From 60° to 79°*5.

In hydrogen. In olefiant gas,

4th. From 60° to 70°-.5. From 60° to 76^-5*.

On a different day I tried the following experiments ; all
the circumstances were the same, excepting that the battery
was in more energetic action, for which reason I have not
tabulated them with the others.

In oxygen associated with coal gas the thermometer rose In
five minutes —

In oxygen. In coal gas.

From 60° to 82°. From 60° to 76°.

In hydrogen associated with coal gas the thermometer rose
in five minutes —

In hydrogen. In coal gas.

From 60°'to 77°. From 60° to 82°'5.

From this it would appear that coal gas should be placed, as
to its cooling effect on the ignited wire, between hydrogen
and olefiant gas.

On another day sulphuretted hydrogen associated respec-
tively with oxygen and hydrogen was tried ; the wire in the
sulphuretted hydrogen was at first ignited to a degree some-
what inferior to that in oxygen, but the gas was rapidly de-
composed ; sulphur being deposited on the interior of the
vessel and the intensity of ignition gradually decreased, so as
ultimately to be scarcely superior to the ignition in hydrogen :

* I should perhaps remark, that several test experiments were tried to
ascertain the working of the apparatus ; thus, the same gas was placed in
both tubes, and the results given by the thermometer were found to be
accurately the same in both vessels. The tubes were also changed with
reference to the containing vessels and to the contained gases. The water
was always agitated to render its temperature uniform previously to reading
off, &c. &c.

surrounding Media on Voltaic Ignition. 117

indeed the gas by this time had become nearly pure hydrogen.
The following were the effects on the thermometer in five
minutes, all being arranged as before : —

In oxygen. In sulphuretted hydrogen.

From 60° to 86°. From 60° to 76°.

In hydrogen. In sulphuretted hydrogen.

From 60° to 79**. From 60° to 81°-5.

This result would place sulphuretted hydrogen between
hydrogen and coal gas ; but as the gas was rapidly decom-
posed, the greater part of the experiment was made with hy-
drogen containing small quantities of sulphur combined, and
not with sulphuretted hydrogen. 1 therefore think that proto-
sulphuret of hydrogen, or the gas which consists of equivalent
ratios of the two elements, would be much further removed
from pure hydrogen ; probably it would be about equal in its
cooling effect to carbonic acid or carbonic oxide.

In phosphuretted hydrogen the platinum wire is destroyed
by combining with the phosphorus the instant it reaches igni-
tion, so that its relation to the other gases could not be ascer-
tained.

Protoxide and deutoxide of nitrogen are, as I have ob-
served in the Bakerian Lecture, decomposed by the ignited
wire; they, as well as atmospheric air, are, as nearly as may
be, equal in their effect to their elements separately.

In the vapour of aether the ignited wire is extinguished
nearly as completely as in hydrogen ; I have not yet tried its
comparative effect, but should judge it to be nearly the same
as coal gas or olefiant gas.

In my former experiments* the following was the order of
the gases, testing the intensity of ignition by the inverse con-
ducting power of the wire, as measured by the amount of gas
in a voltameter included in the circuit.

Cubic inches of gas evolved in
Gases surrounding the wire. the voltameter per minute.

Hydrogen 7*7

Olefiant gas 7*0

Carbonic oxide 66

Carbonic acid 6'6

Oxygen 6'5

Nitrogen 6'4

Assuming that in the present experiments the heat in the
water is a correct indication of the intensity of ignition in the
wire, the order is the same in both series of experiments.

* Philosophical Transactions, 1847, p. 2. [Phil. Mag. S. 3. vol. xxxi. p. 21.]

118 Mr. Grove on the Effect of

Hydrogen is however so far removed from botlf oxygen and
nitrogen in its effects upon the ignited wire, that in order
more accurately to ascertain the relative position of the latter
two gases, I made a few further experiments on them as con-
trasted with each other, and not with hydrogen. I first re-
peated my former experiment on these two gases, varying it
only by changing the circumstances in the manner suggested
by the present experiments, which on account of the vessel
containing the wire being immersed in a given quantity of
water, instead of being exposed to the external atmosphere,
would occasion greater equality in the surrounding cooling
effects, and would give me the opportunity of combining both
methods in one experiment.

I filled both tubes A and B with oxygen, and included a
voltameter in the circuit ; in two minutes 3"43 cubic inches of
hydrogen were evolved in the voltameter, and the thermometer
in each cell had risen from 60° to 63°. A similar experiment
with nitrogen gave in two minutes 3-4 cubic inches of hydro-
gen, and the thermometer rose from 60° to 63°.

This experiment accords with my previous one as to the
voltameter test, but indicates no difference in oxygen and
nitrogen with the thermometer test; I therefore in the fol-
lowing three experiments associated nitrogen with oxygen in
the apparatus, fig. 1. All things being disposed as with the
experiments on hydrogen associated with other gases, in five
minutes the thermometer rose —

In the oxj'gen. In the associated nitrogen.

Exp. 1st. From 60° to 71°-5. From 60° to 73°.

2nd. 60° to 77°. 60° to 76°.

3rd. 60° to 75°. 60° to 7G°.

Mean ... 60° to 74;°-5. 60° to 75°.

The battery had increased somewhat in power after the
first experiment, but as both wires formed part of the same
circuit in each experiment, the variations in battery power do
not affect the comparative results. The second experiment
gives a variation in the position of oxygen and nitrogen with
i-eference to the first and third experiments, but the gases so
nearly approach in their cooling effects, that these slight dif-
ferences are not much to be relied upon; however I applied a
further test. I associated in turn oxygen and nitrogen with
carbonic acid ; the following were the results. In five minutes
the thermometer rose —

In oxygen.

In carbonic acid,

Exp. 1st.

From 60° to 75'.

From 60° to 75°.

2nd.

60" to 76^

60" to 75°.

surrounding Media on Voltaic Ignition. 119

In nitrogen. In carbonic acid.

Exp. 1st. From 60° to 74°. 60° to 73°.

2nd. 60° to 73°. 60° to 72°'5.

The battery had in the last experiment a little decreased in
power; the oxygen and nitrogen both produced a less cooling
effect than the carbonic acid, but the oxygen came nearer to
it than the nitrogen, thus according with the previous experi-
ments. Upon the whole it would appear that oxygen pro-
duces a somewhat greater cooling effect on the ignited wire
than nitrogen, but these gases may, for the purposes of this
paper, be fairly regarded as equal. Atmospheric air produces
a similar effect to oxygen and nitrogen separately, though I
am inclined to think that a slight chemical change takes place
when atmospheric air is exposed to the ignited wire, and that
nitrous acid is formed; for if litmus paper be held over a vol-
taically ignited platinum wire in the air, a slight but very per-
ceptible tinge of red marks the portion of it immediately over
the wire.

With the view of ascertaining whether the specific heat of
the surrounding media were the cause of the phaenomenon, I
proceeded to try the effect of the wire carrying a voltaic cur-
rent on different liquids; all things being disposed as in the
previous experiments, and 3 oz. of water being associated
respectively with the same quantity of the following liquids.
The thermometer rose in five minutes —

In water, from 60°to 70°-3. In spirit of turpentine 60°to88°. i

In water, from 60° to 70°-3.

In sulphuret of carbon 60°to87°'l.

In water, from 60° to 69°.

In olive oil . . . 60° to 85°.

In water, from 60° to 70°- 1 .

In naphtha . . . 60°to78°-8.

In water, from 60° to 70°-5.

In alcohol sp.gr. 0-84 60°to77°.

In water, from 60°to68°-5. In aether . . . . 60°to76°-l.

I do not much rely on the last experiment, — the battery
was in more feeble action ; and though each of the above re-
sults is the mean of three experiments, yet the variations in
the results of the different experiments with aether being con-
siderable (while in the others they were very trifling), lead me
to place no great dependence on it. The rapidity of evapo-
ration and the readiness of ebullition of the aether require that
a larger quantity should be used ; but as this for the purpose
of comparison would have required all the experiments to be
repeated with different quantities of liquid, I have not thought
it worth while to go through the series a second time. It will

120 Mr. Grove on the Effect of

be observed, that the effects with the above liquids are by no
means in direct relation with their respective specific heats ;
but in order to bring the results of the experiments with
liquids into comparison with those with gases, I now asso-
ciated a gas with a liquid, viz. hydrogen with water. All
things being disposed as before, the tube A was filled with
hydrogen gas, the tube B with water, both being immersed in
3 oz. of water. The thermometer rose in five minutes —
In hydrogen. In water.

From 60° to 75°-S. From 60° to 72°.

This experiment of itself conclusively negatives the possi-
bility of specific heat alone accounting for the phaenomenon
under consideration ; and though, doubtless, specific heat
must have some influence on the cooling effects of different
gases and liquids, yet in the former it is apparently of very
trifling import in comparison with the real physical cause of
the differences, whatever that may be.

Supposing, as is stated by Faraday*, that gases possess
feeble conducting powers for voltaic electricity, and supposing
hydrogen, from its close analogy in chemical character to
the metals, to possess a greater conducting power than the
other gases, this would account for its peculiar effect on the
ignited wire, as a certain portion of the current, instead of
forcing its way through the wire, would be carried off by the
surrounding gas. In order to ascertain this I arranged the
following experiments.

1st. Into the closed end of a bent tube, fig. 2, a loop of
platinum wire, AB, and two separate platinum wires CD,
were hermetically sealed, the extremities of the latter being
approximated as closely

as possible, and the in- F'g- ^'

terval between them be-
ing close to and imme-
diately over the apex of
the loop. The tube was
filled with hydrogen,
and the wire AB con-
nected with a voltaic
battery of sufficient
power to raise it to as
high a degree of igni- £-
tion as it would bear
without fusion ; C and -^
D were now connected

* Experimental Researches, §§ 272, 441 and 444

surrounding Media on Voltaic Ignition.

121

with the poles of another battery, a delicate galvanometer
being interposed in the circuit. Not the slightest effect on
the galvanometer needle could be detected, and a similar
negative effect took place when the tube was filled with atmo-
spheric air.

2nd. Parallel portions of platinum wire were now arranged
in close proximity {see fig. 3.), and so that each might be
ignited to a full incandescence by separate insulated batteries.
When surrounded by atmospheres, both of atmospheric air
and of hydrogen, and fully ignited, not the slightest conduc-
tion could be detected, across the interval between the wires,
with ten cells of the nitric acid battery, and being enabled by
the kindness of Mr. Gassiot to repeat this experiment with
his battery of five hundred well-insulated cells of the nitric
acid combination, air did not conduct when the ignited wires
were approximated to the one-fiftieth of an inch; on ap-
proaching them nearer they came within striking distance,
were instantly fused, and the galvanometer needle, which had
up to this time been perfectly stationary, was whirled rapidly
round.

I think I am entitled to conclude from this, that we have
no experimental evidence that matter in the gaseous state con-
Fig. 3.

ducts voltaic electricity; probably gases do not conduct
Franklinic electricity, as the experiments which would seem
prima facie to lead to that conclusion, are explicable as re-
sulting from the disruptive discharge.

In Faraday's experiment two wires were approximated in
the flame of a spirit-lamp, and a slight conduction across the
interval in the flame was observed. This conduction might
have been due to certain unconsumed particles of carbon ex-
isting in the flame, or possibly to the flame itself; according
to Dr. Andrews, flame, even that of pure hydrogen gas, con-
ducts voltaic electricity*.

I now endeavoured to ascertain whether any specific inductive
effect of the hydrogen might have an influence : parallel wires
of platinum and parallel coiled copper wires were placed in
atmospheres of hydrogen and of atmospheric air, one of which
parallel wires conveyed the current, and the other wire was
connected with a delicate galvanometer. I could detect no

* Phil. Mag, vol. ix. p. 176.

122 Mr. Grove on the Effect of

difference in the arcs of deflection of the needle at the instant
of meeting or breaking contact, whether the wires were in
atmospheres of hydrogen or of atmospheric air; nor when
parallel platinum wires with their surrounding atmospheres of
gas were immersed in a given quantity of water, could I detect
any difference in the resulting heat, whether the current passed
in the same or in a different direction through each wire.

My next object was to ascertain whether, in cases of ordi-
nary ignition, the same apparent annihilation of lieat took
place in hydrogen gas as with voltaic ignition. Two iron
cylinders AB, fig. 4<, each weighing 390 grains, were attached
to long iron wires bent back Fig. 4.

in the form shown in the
figure. The cylinders were
placed together in a crucible
of fine sand, and the whole
heated to a uniform white
heat. The cylinders were
now taken out of the sand,
placed atthe surface of equal
portions of water in the ves-
sels C and D ; two inverted
tubes, e^f the one of hy-
drogen, the other of atmo-
spheric air, were placed over
them, and the whole quickly immersed in the water, and re-
tained by a little contrivance, which I need not particularize,
in the position shown in the figure. The temperature of the
water at the commencement of the experiment was 60° Fahr.
In four minutes the water surrounding the hydrogen had risen
to 94;°, and became stationary there, while that surrounding
the air had only reached 87°; in ten minutes the water sur-
rounding the hydrogen had sunk to 92°*5, while that sur-
rounding the air had risen to 93°, which was the highest tem-
perature it reached ; thus the respective maxima were 94° and
93°; but considering the greater time which the water sur-
rounding the air required to attain its maximum temperature,
and that being during this time at a temperature above that
of the surrounding atmosphere, it must have lost something of
its acquired heat, we may fairly consider the maxima to be the
same, and that the difference of effect in the two gases had
reference solely to the time occupied in the transference of the
heat. In a second experiment the results were similar, the
maximum being in this experiment 92'5 in hydrogen, and 91
in air*.

* Iron wire produces a similar effect to platinum wire in the voltaic ox-
peiiments.

6

surrounding Media on Voltaic Ignition. 123

As far as ordinary ignition is concerned, hydrogen has been
shown by the experiments of Leslie and Davy to produce a
more rapid cooling effect than air ; and the above experiment
having shown that it does not alter or convert into any other
force the actual amount of heat given off, my next step was to
inquire whether this rapidity of cooling effectof the hydrogen
would account for the effects observed with voltaic ignition.
Although the two classes of effects were apparently very dif-
ferent, it might be that the improved power of conduction
arising from the rapid cooling effect of the hydrogen might,
by enabling the current to pass more readily, carry off the
force in the form of electricity, which if the wire offered more
resistance (as it would when more highly ignited) would be
developed in the form of heat. By employing the same me-
dium, but impeding the circulation of the heated currents in
one case, while their circulation was free in the other, some
light might be expected to be thrown on the inverse relation
of the conducting power to the heat developed. The follow-
ing experiment was therefore tried.

In the apparatus represented in fig. 1, tube A was uncorked,
so as to allow free passage for the water, while tube B was
filled up w^ith fine sand soaked with water, and then corked
at both ends ; the current was passed and the following was
the result. In the vessel containing tube A, the thermometer
rose in five minutes from 52° to 60°, and in that containing
tube B from 52° to 60° also; during a second five minutes,
the thermometer rose in the vessel containing A from 60° to
67°, and in the vessel containing B from 60° to 67° also.

I tried another analogous experiment: a coil of platinum
wire was placed in a very narrow glass tube one-sixth of an
inch diameter; this was hermetically sealed at one end, and
the other drawn into a very narrow aperture, little more than
sufficient to allow the platinum wire to pass, and filled with
water (it was necessary to leave a small aperture to prevent
the bursting of the tube by the expansion of the heated water);
in the other vessel a similar coil of platinum wire was placed,
but without any glass tube at all. The circuit having been
completed as before, the thermometer rose in five minutes —

In the water without the tube, from . 60° to 87°.
In the water containing the tube, from 60° to 86°.

Here the difference, slight as it was, was against what theory
would have led one to anticipate; the exact equality however
of the previous experiment, and the close approximation of
the results in this one, afford no conclusive information as to
the point under consideration, though the negative result

r^v

1 24. Mr. Grove on the Effect of

rather tends against the view which would assimilate the effects
of voltaic to those of ordinary ignition.

As another method of attaining the object before mentioned,
viz. the inverse relation of the conducting power of the wire
to the heat developed in it, 1 tried the following experiment.
A platinum wire of one foot long and one-eightieth of an inch
diameter was ignited in air by ten cells of the battery, a volta-
meter being included in the circuit; the amount of hydrogen
given off by the voltameter was one cubic inch in forty-four
seconds : half the wire was now immersed in water of the
temperature of 60° F. ; by this means the intensity of ignition
of the other half was notably increased ; the voltameter now
yielded one cubic inch in forty seconds : two-thirds of the
wire immersed, gave one cubic inch in thirty-seven seconds;
and five-sixths immersed, gave one cubic inch in thirty-five
seconds. The heat of the portion of wire not immersed in
water had in the last experiment nearly reached the point of
fusion of the platinum. By this result it appears that the
increased resistance to conduction of the ignited portion is not
equal to the increased conducting power of the cooled portion
of the same wire.

With a view of seeing how far the cooling effect upon the
ignited wire might be due to the greater or less fluency or
mobility of the particles of the different media surrounding it,
1 have looked into the papers of Faraday* and of Graham f.
In the experiments of the former, it appears that the escape
of different gases at a certain pressure through capillary tubes,
or the velocities of revolution of vanes or floats surrounded by
different gases, was in some inverse ratio to the density of
such gases ; and the experiments of the latter show that the
effusion or escape of gases through a minute aperture in a
plate, takes place with velocities inversely as the square root
of their specific gravities. In Graham's experiments, how-
ever, when the escape took place through capillary tubes, the
results seemed subject to no ascertained law, though the com-
pounds of carbon with hydrogen passed through with greater
facility than other gases.

The cooling effects of gases on the ignited wire are decidedly
not in any ratio with their specific gravities ; thus, carbonic
acid on the one hand, and hydrogen on the other, produce
greater cooling effects than atmospheric air ; and olefiant gas,
which closely approximates air, and is far removed from hy-
drogen in specific gravity, much more nearly approximates
hydrogen, and is far removed from air in its cooling effect.

* Quarterly Journal of Science, vol. iii. p. 354.
t Philosophical Transactions, 1846, p. 673.

surrounding Media on Voltaic Ignition. 125

Upon the whole, we may conclude, from the experiments
detailed in this paper, that the cooling effect of different gases,
or rather the difference in the cooling effect of hydrogen and
its compounds from that of other gases, is not due to differences
of specific heat ; it is not due to differences of specific gravity ;
it is not due to differences of conducting powers for electricity ;
it is not due to the character of hydrogen in relation to its trans-
mission of sound, noticed by Leslie, for reasons which I have
before given*; it is not due to the same physical characters
of mobility which occasion one gas to escape from a small
aperture with greater facility than another; but it may be,
and probably is, affected by the mobile or vibratory character
of the particles by which heat is more rapidly abstracted. I
at one time thought that the effect might have relation to the
combustible character of the gas, and that the electro-negative
gases were in respect to it contra-distinguished from the elec-
tro-positive or neutral gases, but the experience I have ob-
tained from the experiments detailed here induces me to
abandon that supposition.

I incline to think, that, although influenced by the fluency
of the gas, the phaenomenon is mainly due to a molecular
action at the surfaces of the ignited body and of the gas. We
know that in the recognised effects of radiant heat, the physical
state of the surface of the radiating or absorbing body exercises
a most important influence on the relative velocities of radia-
tion or absorption; thus, black and white surfaces are, as
every one knows, strikingly contra-distinguished in this re-
spect: why may not the surface of the gaseous medium conti-
guous to the radiating substance exercise a reciprocal influ-
ence ? why may not the surface of hydrogen be as black, and
that of nitrogen as white to the ignited wire ? This notion
seems to me the more worthy of consideration as it may esta-
blish a link of continuity between the cooling effects of differ-
ent gaseous media and the mysterious effects of surface in
catalytic combinations and decompositions by solids such as
platinum. Epipolic actions will, I feel convinced, gradually
assume a much more important place in physics than they
have hitherto done; and the further development of them
appears to me the most probable guide to the connexion by
definite conceptions of physical and chemical actions.

The difference of the cooling effect of hydrogen, and of
those of its compounds, where it is not neutralized by a pow-
erful electro-negative gas, from all other gases, is perhaps the
most striking peculiarity of the phaenomena I have described.

* Philosophical Transactions, 1847. [Phil. Mag. S. 3. vol. xxxi. p. 22.]

126 On the E^eci of swTOtinding Media on Voltaic Ignition.

The differences of effect of all gases other than hydrogen and
such compounds are quite insignificant when compared with
the differences between the hydrogenous and the other gases.
There are some phaenomena which I have before observed,
and which were, at the time I noticed them, inexplicable to
me; but they now appear dependent on this physical pecu-
liarity of hydrogen. Thus, if a jet of oxygen gas be kindled
in an atmosphere of carburetted hydrogen, the flame is smaller
than when the converse effect takes place. The voltaic arc
between metallic terminals is also much smaller in hydrogen
gas than in nitrogen, though both these gases are incapable of
combining with the terminals; indeed to obtain an arc at all
in hydrogen is scarcely practicable.

Davy has, in his Researches on Flame, given several expe-
riments which are similarly explicable; but though noting the
results, he nowhere, as far as I am aware, attributes them to
any specific peculiarity of hydrogen.

Of the phaenomenon which I have examined in this paper,
I first published an account in connexion with some experi-
ments on the application of voltaic ignition to lighting mines,
and it does not appear impossible that the experiments now
detailed may ultimately find some beneficial application in
solving the problem of a safety-light for mines. A light which
is just able to support itself under the cooling effect of ordi-
nary atmospheric air would be extinguished by air mixed with
hydrogenous gas.

I am far from pretending to have devised any means of ful-
filling these conditions, and yet supplying an efficient light;
I merely throw it out as a suggestion for consideration, know-
ing that there are no additions to our knowledge which are
not ultimately valuable in their practical application; and
that a suggestion, however vague, — a new point to those whose
minds may be occupied with the subject, may lead them to
results which he who makes the suggestion is unable to attain.

P.S. Since this paper was communicated I have received a
paper from Dr. Andrews of Belfast, who published as early
as 1840, in the Proceedings of the Royal Irish Academy, ex-
periments similar to those of mine first puV)lished in 1845.
My experiments were made in the same year as those of Dr.
Andrews, but as 1 withheld their publication, Dr. Andrews is
fully entitled to priority. Had I known of his experiments
earlier, I should have recited them in the first part of this
paper.

[ 127 ]

XVI. Practical application of the Law poitited out by Dr. R.
D. Thomson, of the proper Balance of the Food in Nutri-
tion. By Dr. C. Remigius Fresenius, Professor of Che-
mistry at the Agricultural Institute of Wiesbaden*.

IN reference to the question concerning the relation which
must subsist between the nitrogenous and non-nitrogenous
nutritive substances in the food oi men and animals, it is but
due to Dr. R. D. Thomson to acknowledge, that he considers
this the most important circumstance in nutrition, and was
the first to call attention to it.

This relation is obviously different in various classes of
animals, and besides it must be different even in the same class
of animals, according to their mode of life and to the amount
of exercise they undergo.

An animal which is hard worked will require a different
proportion to one which stands at rest in a stable ; still
more different must be the proportion when our object is to
fatten the animal. I consider it to be one of the most im-
portant tasks of dietary and the feeding of cattle, to fix the
requisite proportions suited to the various modes of life, for it
may be understood that these limits cannot be overstepped on
either side without injury.

Let us suppose, for instance, an animal requires under cer-
tain circumstances the proportion of 1 nitrogenous (nutritive)
to 5 non-nitrogenous (calorifiant) constituents in its food ; but
if we give it food in which the proportion of 1 to 10 prevails,
there will be, in the process of nutrition, for every 1 part
nitrogenous only 5 parts non-nitrogenous assimilated ; the
other half of the non-nitrogenous (calorifiant) aliment will be
wasted t.

But it is not the pecuniary loss alone which arises through
this, that deserves consideration ; for it is clear that the animal
will be burdened with the process of getting rid of the unas-
similated half; for this object strength is required, which
might otherwise have been spared.

If we give it food containing too large a proportion of nitro-
genous aliment, in favourable circumstances it will consume
the dearer instead of the cheaper non-nitrogenous aliment;

* Translated from the Lehrbnch der Chemiefiir Landwirthe, Forstmdnner
und Cameralisten vo7i Dr. C. Remigius Fresenius (1847), page 480, by Wil-
liam Augustus Perston.

t The original passage is "So wird es beim Ernahrungsprocesse auf je
1 Thl stickstofFhaltige eben doch nur 5 Thle stickstoffreie Besthandtheile
verwenden, die andere Halfte der slickstofFhaltigen Nahrungsmittel wird
vergeudet." The true reading it is apprehended ought to be stickstoffreie
Nahrungsmittel, and it has thus been rendered in the English version. — Trans.

1 28 On the proper Balance of the Food in Nutrition,

but in unfavourable circumstances it will become diseased, by
being compelled to act in opposition to nature.

Taking it for granted that the requisite proportions for dif-
ferent circumstances were ascertained, the choice of aliment
could be regulated on the most rational basis.

[We speak here primarily only of the absolute strength of
nourishment, without noticing the greater or less degree of
digestibility possessed by equally nutritious substances, and the
proportion of unassimilable constituents which they contain.]

We observe, for instance, that cows on a meadow, feeding
only upon grass, enjoy good health. Now let us endeavour
to ascertain how we can produce the same proportion of non-
nitrogenous and nitrogenous aliment with other descriptions
of food.

The proportion which exists in grass or hay is 1 to 8* 3, as
in the following Table: —

Relation
of 1 part
nitroge-
nous to
non-nitro-
genous.

I.

Relation
of 1 part
nitroge-
nous to
salts.

II.

The following quantities contain 1 part
of nitrogenous matter.

Nitroge-
nous, non-
nitroge-
nous and
salts.
III.

Dried at
212°.

IV.

Dried in
air.

V.

Fresh sub-
stances.

VI.

French beans

1-81
1-87
208
2-14
2-42
4-08
4-25
4-42
5-08
6-08
6-39
6-55
7-26
7-84
8-30
9

12-5
14-2
14-8
24-4
293
41-
121-6

015
0-09
0-15
0-11
Oil
0-24
0-27
0-13
0-42
0-60
0-55
0-10
0-44
0-55
0-73
0-40
2-04
2-48
010
1-93
308
018
0-40

2-96

2-96

3-23

3-25

3-53

5-32

5-52

5-55

6-50

7-68

7-94

7-65

8-70

9-39

10-03

10-40

15-54

17-68

15-90

27-33

33 38

4218

12300

3-45
3-45
3-66
3-66
4-21
6-41
6-53
6-29
6-45
7-68
7-91
8-13
8-65
9-39
10-73

4b-6()

4000
16-61
53-48
52-35

4-00
4-00
4-29
4-28
4-85
7-35
7-57
7-24

"'9-72

"9-34

i'2-4'7

55-55
54-05
18-41
65-79

58-82

353
32-0
65-1

48-8
67-6
32-8
41-2

175-4
1250-

Field beans

Peas

"Wheat

Oats

Rve

Red turnips

White turnips

Indian com

Mangel-wurzel ...

Meadow-grass . . .
Potatoes

Oat-straw

Wheat-straw

Rice

Rye-straw

Barley-straw

Cherries

Pears

This Table, as given by Fresenius, is derived from German authorities,
including several results obtained and published by Dr. Thomson in his
Researches on Food, p. 167- See also Phil. Mag., vol. xxxii. p. 459. There is
therefore some discrepancy when compared with English grain, the German
grain being richer in nitrogen. See Dr. Thomson on the Composition of
German and English Bread, Phil. Mag. vol. xxiii. p. 321.

On the proper Balance of the Food in Nutrition. 129

Were we then to give them carrots, in which 1 part nitroge-
nous is contained tor every 7*84 parts of non-nitrogenous con-
stituents, the proportion would not be materially ilisturbed;
but were we to give them potatoes (1 : 9), we disturb the pro-
portion somewhat more. It is therefore expedient to feed
them with a substance which is richer in nitrogen ; this proper
proportion may be obtained with exactness by mixing 1 nutri-
tious equivalent of red clover with 3 nutritious equivalents of
potatoes : —

1x1:6 =1: 6

3x1 :9-00 = 3:27

4:33 or 1 : 8*25.

To produce this mixture, we feed them by giving them
9'7lbs. of dried clover for every 123*6 lbs. of potatoes.

If we wished to give them the same proportion in white
turnips and oat-straw, we must supply for every 2 nutritious
e()uivalents of the former 1 nutritious equivalent of the latter ;
for this mixture gives the proportion of 1 to 8*4; that is, they
must be ie(\ with 130 lbs. of fresh white turnips for every
55'55 lbs. of dried oat-straw.

A horse that works hard requires the proportion of 1 to 4,
For this we give him oats which represent that proportion.
But if we wished to give him the same proportion in field
beans and hay, we must take for every 2 alimentary equiva-
lents of the former 1 alimentary equivalent of hay, for such a
mixture has the proportion of 1 to 4'1. We ieed liim there-
fore with 8"58 lbs. of dry field beans for every 12*47 lbs. of
dry hay.

A man requires for a certain mode of life the proportion o^
1 to 3. He wishes to eat beef and potatoes; he must, there-
fore, for every 2 alimentary equivalents of beef eat 1 alimentary
equivalent of potatoes, for this mixture gives the proportion
of 1 to 3'01 ; he must therefore use for every 2 lbs. of boiled
beef (reckoned without water) 41 lbs, of potatoes (reckojned in
the fresh state).

If he wished to produce the proportion of 1 to 4 with car-
rots and raw bacon, he will attain it by mixing $ alimentary
equivalents of the former with 6 alimentary equivalents of the
latter, which represent the proportion of 1 to 3*99. For this
purpose he must eat 338 parts of fresh carrots for ievery 11
parts of raw bacon (reckoned free from water).

Concerning the question, as to what is the proper xjuantity
of aliment (possessing die due proportions) which is to be
given under different circumstances, experience alone can de-
termine it. For the computation, how the necessary quantity

Phil. Mag. S. 3. Vol. 35. No. 234. Aug. 1849. K

130 On the proper Balance of the Food in Nutrition,

may be given in diverse properly assorted alimentary mixtures,
we would refer to the divisions III., IV., V. and VI. of the
foregoing table.

If a cow requires in twenty- four hours 10 kilogrammes
(22 05 lbs. avoirdupois) of air-dried hay, how many kilo-
grammes of the mixture given above of clover and potatoes
would it require to replace it?

10 kilogrammes of air-dried clover contain in all S'O'i kilo-
grammes (17*728 lbs. avoirdupois) of nutritious matter, for
12-47 : 10-03=10 : .r
.r=8-04.
That mixture will consist of 9' 7 kilogrammes (21*38 lbs. avoir-
dupois) of dry clover, which contain in all 7'68 kilogrammes
(16-93 lbs.) of nutritious matter and 123*6 kilogrammes (272*5
lbs.) of potatoes, which contain in all 31*20 kilogrammes
(68*79 lbs.) of nutritious matter.

133*3 kilogrammes (293*93 lbs.) of the mixture contain ac-
cordingly S8*88 kilogrammes (85*72 lbs.) of nutritious matter.

38*88 kilogrammes (85*72 lbs.) of the joint nutritious mat-
ters are equal to 133*3 kilogrammes (293*93 lbs.) of the mix-
ture. How many are SO* equal to? x = 27'5 (6063 lbs.).

27*5 kilogrammes (6063 lbs.) of the mixture in question
are equivalent to 10 kilogrammes (22*05 lbs.) of hay in the
proportion and quantity of nitrogenous and non-nitrogenous
alimentary substances. In a precisely similar manner the
kind and quantity of the salts must be attended to in practice.

Conclusions from the foregoing.

We have approximated much more closely to the object
we had in view, viz. a completely rational system of nutrition,
than it has hitherto been possible to do, and can answer the
proposed questions with perfectly accurate average numbers ;
and we have now only duly to consider the influence which
the unappropriated portions of food exert on the body (the
getting rid of them involves a waste of strength) ; and further,
the greater or less degree of digestibility {der leichteren oder
schwerereji, schnelleren oderlafigsameren Verdaidichkeit) of each
species of aliment, in order to do it with perfect precision.

But we can even now, from what has already been stated,
educe safe and weighty conclusions, namely the following: —

1. It is an impossibility to sustain either a mart or a beast
on food entirely devoid of nitrogen, however great in quantity
it may be.

2. All that has been said in the older as well as in many of
the newer books on husbandry, respecting the relative nutri-
tive value of different kinds of forage, cannot, inasnTUch as it

071 the j>roper Balance of the Food in Nutrition. 131

was not arrived at by experience, but deduced from theoretical
views, possibly be correct, because these views do not accord
with facts.

3. The discovery of the true relative value of aliment, and
of the proportion in which it may be replaced, may be ascer-
tained without much difficulty, so long as chemists and farmers
work hand in hand for the exact solution of the above ques-
tions.

4. A completely rational system of nutrition, that is such an
one as combines the greatest amount of strength with the
least consumption of nourishment, will then be possible.

5. A loss of nutritious matter and of strength often takes
place where it would be least expected, namely by the con-
sumption of all kinds of food (or forage) where the due pro-
portion between nitrogenous and non-nitrogenous constituents
does not exist, say by eating only fruit or potatoes.

6. It can with safety be decided by the above under what
circumstances substitutes for bread may be employed, and
what is their respective value for each desired proportion.

Raw and cooked Articles of Food.

Many kinds of food cannot be eaten raw by man ; others,
although they may be eaten raw, agree much better with us
when cooked.

Hence boiling, roasting, baking, &c. has a twofold effect;
primarily, it converts indigestible or food difficult of digestion
into a digestible or more easily digestible condition. Thus,
starch is converted into gelatinous starch, into dextrine or
sugar; cartilaginous substances into glue; and chondrine,
fibrine, into changed fibrine, &c. Secondly, it frequently
confers upon them an agreeable taste.

But can the real nutritive value of food be augmented by
cooking? Impossible ! Still it may be of the greatest benefit
in feeding cattle to cook their food. The advantage accrues
in this way : that potatoes, turnips, &c. are more quickly and
more easily digested when boiled than raw ; and thus there is
much less chance for any portion to be thrown off in an un-
digested state (unassimilated). Its warmth gives also a slight
advantage to cooked food; it deprives the body of no heat;
and the non -nitrogenous substances, which in the cold food
would have been required to affiard heat, can be used for the
production of fat. But whether cold or warm food is to be
preferred in a practical point of view cannot from all this be
conclusively deduced. It is a question only to be answered
by experience, for the result is entirely dependent on the na-
ture and requirements of the animal.

K2

[ 132 ]

XVII. On the alleged Evidence for a Physical Cotmexion
between Stars forming Binary or Multiple Groups, arisingfjom
their Proximity alone. By Prof. J. D. Fo^t&es,F.R.S. ^c.

To the Editors of the Philosophical Magazine and Journal.
Gentlemen, Melrose, July 13, 1849.

IN conformity with usage and with the spirit of your Journal,
I may perhaps be permitted to suggest a doubt as to the
legitimacy of certain reasonings with respect to the evidence
for the physical co?inexio?i of binary or multiple stars arising
ii-oni the mere fact of their juxtaposition, as stated and applied
by some of the most eminent writers on sidereal astronomy.
I should probably have hesitated to oppose my solitary opinion
to that entertained by the eminent writers whom I am about
to quote, had I not found it to be entirely supported by the
eminent authority of two friends to whom I separately pro-
posed it.

Nearly a century ago, Mitchell computed the chances to be
500,000 to 1 against the stars composing the group of the
Pleiades he\i\g fortuitously concentrated within the small ap-
parent space w hich they occupy : and he thence infers the
probability of a physical connexion between them. Struve
has pushed this consideration much further. In his classifi-
cation of double stars he has applied the same argument to
estimate the improbability of the occurrence of even single pairs
of stars in close proximity. He " calculates the odds at 9570
to 1 against any two stars from the 1st to the 7th magnitude
inclusive, falling (if fortuitously scattered) within 4" of each
other. Now the number of such binary calculations actually
observed at the date of this calculation was already 91, and
many more have been added to the list. Again, he calculates
that the odds against any such stars fortuitously scattered fall-
ing within 32" of a third, so as to constitute a triple star, is
not less than 173,524 to 1. Now, four such combinations occur
in the heavens." Sir John Herschel, from whose Outlines of
Astronomy I take this statement of Struve's results, adds,
" the conclusion of a physical connexion of some kind or other
is therefore unavoidable*."

Now I confess my inability to attach any idea to what would
be the distribution of stars or of anything else, if " fortuitously
scattered," much more must I regard with doubt and hesita-
tion an attempt to assign a numerical value to the antecedent
probability of any given arrangement or grouping whatever.

* Outlines of Astronomy, p. 564. If I recollect aright, the passage does
not occur in the edition in Lardner's Cyclopaedia.

Sir W. Rowan Hamilton on Quatermofis. 133

An equable spacing of the stars over the sky would seem to me
to be far more inconsistent with a total absence of Law or Prin-
ciple, than the existence of spaces of comparative condensa-
tion, including binary or more numerous groups, as well as of
regions of great paucity of stars. Thus, to take a familiar
instance : — No bad representation of stars and their distribu-
tion may be made by sparking viscid white paint from a coarse
brush upon a dark ground. It is impossible to conceive a
nearer approach to a "random scattering." But I am assured
by an ingenious friend, who has used this contrivance in aid
of pictorial effect, that such an artificial galaxy will present
every variety of grouping, with double and treble points in-
numerable (as I have indeed myself witnessed); nor can I
well see how upon any reasonable theory of chance it should
be otherwise.

I wish to restrict this letter to the end proposed, that of
nakedly setting forth a serious difficulty in an inferential inter-
pretation of nature, sanctioned by high and also cumulative
authority. I shall not therefore attempt now to inquire more
minutely into the history of the error, if. error it be, nor to insist
on the great importance of arguing correctly in cases which
admit of so very extensive application.
I remain. Gentlemen,

Yours faithfully,

James D. P'orbes.

XVIII. On Qtiaternions ; or on a New System of Imaginaries
in Algebra. By Sir William Rowan Hamilton, LL.D.^
M.R.I.A,^ F.R.A.S.i Corresponding Member of the Insti-
tute of France^ Sfc., Andrews' Professor of Astronomy in the
University of Dublin ^ mid Royal Astronomer of Ireland.

[Continued from vol. xxxiv. p. 439.]

82. ^I^HIS seems to be a proper place for inserting some
A notices of investigations and results, respecting the
inscription of rectilinear (but not generally plane) polygons,
in spheres, and other surfaces of the second degree.

Let p and <r be any two unit- vectors, or directed radii of an
unit-sphere ; so that, according to a fundamental principle of
the present Calculus, we may write

p2 = cr2=-l (237.)

We sliall then have also,

0 = <r"— p'^ = (r((r-p) + (<r-p)p, . . . (238.)

IS* Sir W. Rowan Hamilton on Quaternions.

and consequently

0-=— (o-— p)p((j--p)-'=— XpX-», . . (239.)

if X be the directed chord tr—p itself, or any portion or pro-
longation thereof, or any vector parallel thereto. If then p, pj,
Pv •'• Pm be any series or succession of unit-vectors, while X^,
X2, ... X„ are any vectors respectively coincident with, or
parallel to, the successive and rectilinear chords of the unit-
sphere, connecting the successive points where the vectors
p • . Pn terminate; and if we introduce the quaternions,

§'i = Xi; §'2=Vi; 9'3= Va^ ; &c., . . (240.)

we shall have the expressions,

pi = -9iPQ\~'-> pi=+Q^9^~'i ps^-qmr''* &c. (24.1.)

Hence if we write the equation

p«=p, (242.)

to express the conception of a closed polygon of n sides, in-
scribed in the sphere, we shall have the general formula,

Pqn={-^T9J>'^ (243.)

which is immediately seen to decompose itself into the two
following principal cases, according as the number n of the
sides is even or odd :

pq2m=+qimp\ (244.)

P5'2m+1=— 5'2m+lf (245.)

The equation (244.) admits also of being written thus, by the
general rules of quaternions,

0 = y.pYq,^; (246.)

and the equation (245.) resolves itself, by the same general
rules, into the two equations following :

0 = S^2m+i; 0 = S. qum+ip. . . • (247.)
We shall now proceed to consider some of the consequences
which follow from the formulae thus obtained.

83. An immediate consequence of the equations (247.), or
rather a translation of those equations into words, is the fol-
lowing quaternion theorem: — If any rectilinear polygon, mth
any odd number of sides, be inscribed in a sphere, the contitmed
product of those sides is a vector', tangential to the sphere at the
Jirst corner of the polygon. It is understood that, in forming
this continued product of sides, their directions and order are
attended to ; the first side being multiplied as a vector by the
second, so as to form a certain quaternion product; and this
product being afterwards multiplied, in succession, by the
third side, then by the fourth, the fifth, &c., so as to form a

KJJir W. Rowan Hamilton on Qtiaternions, 135

series of quaternions, of which the last will (by the theorem)
have its scalar part equal to zero; while the vector part, or the
product itself, will be constructed by a right line with a cer-
tain definite direction, which will (by the same theorem) be
that of a certain rectilinear tangent to the sphere, at the point
or corner where the first side of the inscribed polygon begins.
[The tensor of the resulting vector, or the length of the pro-
duct line, will of course represent, at the same time, by the
general law of tensors, the product of the lengths of the lactor
lines, with the usual reference to some assumed unit of length.]
And conversely, whenever it happens that an odd number of
successive right lines in space, being multiplied together suc-
cessively by the rules of the present Calculus, give a liJie as
their continued product, that is to say, when the scalar of the
quaternion obtained by this multiplication vanishes, then those
right lines may be inferred to have the directio?is of the suc-
cessive sides of a polygon inscribed in a sphere.

84-. Already, even as applied to the case of an inscribed
gauche pentagon, the theorem of the last article expresses a
characteristic property of the sphere, which may be regarded
as being of a graphic rather than of a metric character ; inas-
much as it concerns immediately directions rather than mag-
nitudes, although there is no difficulty in deducing from it
metric relations also : as will at once appear by considering
the formula which expresses it, namely the following,

0 = S.(^-pJ(p4-p3)(p3-p,)(p2-pi)(pi-p). • (24-8.)

(See the Proceedings of the Royal Irish Academy for July
18'l-6, where this quaternion theorem for the case of the in-
scribed pentagon was given.) For the theorem assigns, and
in a simple manner expresses, to those who accept the lan-
guage of this Calculus, a relation between ihejive successive
directions of the sides of a gauche pentagon inscribed in a
sphere, which appears to the present writer to be analogous
to (although necessarily more complex than) the angular rela-
tion established in the third book of Euclid's Elements, be-
tween \\\efour directions of the sides of a plane quadrilateral
inscribed in a circle. Indeed, it will be found to be easy to
deduce the property of the plane inscribed quadrilateral, from
the theorem respecting the inscribed gauche pentagon. For,
by conceiving the fifth side P4P of the pentagon P...P4 to tend
to vanish, and therefore to become tangential at the first corner
p, it is seen that the vector part of the quaternion which is the
continued product of the four first sides must tend, at the
same time, to become normal to the sphere at p ; in order
that, when multiplied into a tangential vector there, it may

136 Sir W. Rowan Hamilton on Qiiaternioiis.

give a vector as the product. Hence the vector part of the
product of the four successive sides of an inscribed gauche
quach'ilateral pp,P2P3, is constructed by a right line which is
normal to the sphere at the first corner; and more generally,
either by the same geometrical reasoning applied to the theo-
rem of art. 83, or by considering the signification of the for-
mula (246.), we may deduce this other theorem, that /^<? wt^or
of the continued product of the sttccessive sides of mi inscribed
gauche polygon p . .v-im-u of any even number ofsides^ is normal
to the sphere at the first corner p. Suppose now the inscribed
quadrilateral, or more frenerally the polygon of 2»i sides, to
flatten into a plane figure ; it will thus come to be inscribed in
a circle^ and consequently in infinitely many spheres at once',
and the only way to escape a resulting indeterminateness in
the value for the vector of the product, is by that vector va-
nishing: which accordingly it may be otherwise proved to do,
although the present mode of proof will appear sufficient to
those who examine its principles with care. And thus we
shall find ourselves conducted to the well-known graphic pro-
perty of the quadrilateral inscribed in the circle, and more
generally to a corresponding theorem respecting inscribed
hexagons, octagons, &c., under the form of the following pro-
position in quaternions, which expresses a characteristic pro-
perty of the circle ; — The vector part of the product of the suc-
cessive sides of antf polygon^ issith any even number of sides, in-
scribed in a circle, vanishes; or, in other words, the product
thus obtained, instead of being a complete quaternion, reduces
itself simply to a positive or negative number. On the other
hand, it is easy to see, from what precedes, that the product of
the successive sides of' a triangle, pentagon, or other polygon of
any odd number of sides, inscribed in a circle, is a vector, which
touches the circle at the first corner of the polygon, or is parallel
to such a tangent.

85. Although the precise law of the relation between the
directions of the sides of an inscribed gauche pentagon, hep-
tagon, &c., expressed by the first formula (247.), is peculiar
to the sphere ; yet it is easy to abstract from that relation a
jpart, which shall hold good, as a law of a more general cha-
racter, for other surfaces of the second order. For we may
easily infer, from that formula, especially when combined with
the other equations of art. 82, that if the first '2m sides of an
inscribed polygon of 2ot sides, p'p'jP'a • • p'2»i» ^^ respectively
parallel to the successive sides of another polygo7i of 2w2 sides,
pPj-.p^m-i, inscribed in the same surface, then the last side,
p'-imP'j of the former polygon, xdll be parallel to the plane which
touches the surface at the ^first corner p of the latter j^olygoji :

Mr. J. (ilaisilier's Remarks on the Weather. 137

and under this form of enunciation, it is obvious that the theo-
rem must admit of being extended, by deformation, to ellip-
soids, and other surfaces of the second degree. We may then
enunciate also this other theorem, respecting the inscription
of rectilinear polygons in such surfaces (which theorem was
communicated to the Royal Irish Academy in March 1849):
— If, after iiiscribing, in a surface of the second degree, any
gauche polygon of 2m sides, pPi . . p^w-m ^''^ ^'''^^ inscribe in the
same surface another gauche polygon, of^m + 1 sides, pVj ..p^^j
under the follovoing 4-m conditions of parallelism :

p'p'i 11 pPi ; p'lP'a II P1P2; • . • p'2m-iP'2m II Pim-iP ; (249.)
and

P'2mP'2m + l|lPP,; P'2m + lP'2m + 2llPlP2; '"^4m-lV' iJl^Im-lP', (250.)

(the first corner p' of the second polygon being assumed at
pleasure on the surface, and the other corners p'p &c., of that
polygon, being successively derived from this one, by drawing
two series of parallels as here directed ;) then the diagonal
plane p'p'.2„,p'4,„, which contains the first, middle, and last corners
of the polygon "with 4m + 1 sides, "will be parallel to the plane
•which touches the surface at the first corner v of the polygon with
2m sides. In fact, the two rectilinear diagonals, p'p^2m and
p'2/HP'4m» will, by a former theorem of the present article, be
parallel to that tangent plane. For example, if the first,
second, third, and fourth sides, of a gauche quadrilateral in-
scribed in a surface of the second order, be parallel to the first,
second, third, and fourth, and also to the fifth, sixth, seventh,
and eighth sides respectively, of a gauche enneagon inscribed
in the same surface; then that diagonal plane of the enneagon
which contains the first, fifth, and ninth corners thereof, will
be parallel to the plane which touches the surface at the first
corner of the quadrilateral.

[To be continued.]

XIX. On the Weather during the Quarter ending June 30,
1849. jRy James Glaishek, Esq., F.R.S., and of the Royal
Observatory, Greenwich *.

DURING the past quarter I have inspected the locality
and the instruments at Exeter, Southampton, Latimer,
Aylesbury, Stone, Hartwell House, Hartwell Rectory, Ox-
ford, Cardington, Liverpool, Leeds, Stonyhurst, York, White-
haven and Newcastle.

The residts furnished to the Registrar-General for the past

* Connnunicaleil by the Author.

138

Mr. J. Glaisher's Remarks on the Weather

quarter are mostly satisfactory; these I have as usual examined
and reduced.

The daily temperatures of the air till April 28 and after
June 6 were for the most part below their average values ; the
mean amount of deficiency in the former period was 3^*7, and
in the latter it was 2°'7. The daily temperatures between
April 29 and June 5 were alternately in excess and defect; the
mean temperature of the interval was somewhat above its
average value. The days whose mean temperatures departed
the most from their averages were April 17, 19, 20, 21 ; May
10 and June 12; the defect in these cases were 11°'2; 14°-5;
10°-4; 11°-1 ; 10°-2; and 10°-7 respectively. The mean tem-
perature of the three months ending May, constituting the
three spring months, was ^S^'S^ and that of the average of the
seventy preceding springs is 46°'7. The several subjects of
research in the past quarter are detailed below.

The mean temperature of the air for the month of April
was 43°"2, hemg less than the average of seventy years by 2°-7,
and less than the average of the preceding eight years by
5°-0.

For the month of May was 54°'0, exceeding the average for
seventy years by 1°'2, and being less than the average of the
preceding eight years by 0°*4. The mean of the quarter was
51°- 7, being 0°'5 less than the average of seventy years, and
2^'l less than the average of the preceding eight years.

For the month of June was 57°'9, being of the same value
as that of the average from seventy years, and being less than
that of the preceding eight years by ]°*9.

Generally the differences of temperature at one place from
the average values for that place sufficiently indicate the de-
partures from the means for all other places ; but in the past
three months this has not been the case, the northern part
of the country having been subjected to a longer continuance
of low temperature than usual, and the departures from the
mean temperatures in the northern parallels of latitude have
been greater than in the southern. This will be more clearly
seen in the following table.

Year.

Mean Temperature of the Air in the Quarter ending June 30.

In Cornwall

and
Devonshire.

South of

Latitude

52°.

Between the
Latitudes of
52° and 53°.

Between the
Latitudes of
53° and 54°.

North of

64°.

1847
1848
1849

5l-3
.541
52-0

5l-9
540
521

51-2
536
500

52-0
520
49-9

4°8-4

507

49-8

during the Qtiarter ending June 30, ISiO. 139

The mean temperature of evaporation at Greenwich —

For the month of April was \l°'5 ; for May was 49'''0; and
for June was 48°-7. These values are 2='-6, 1^-7 and 6°'7 belou\
respectively, the averages of the same months in the prece-
ding eight years.

The mean value for the quarter was 46°*4, which is 3°'6
belo-d) the average of corresponding quarters of eight years.

The mean temperature of the dew-point at Greenwich —

For the months of April, May and June, were 39°'l, 43'''9,
and 48°'4 respectively. These values are l°-8, 3°-9 and 4°-0
beloiso, respectively, the averages of the same months in the
preceding eight years.

The mean value for the quarter was 43°*8, which is 3°*2
below the average from the preceding eight years.

The mean elastic force of vapour for the quarter was 0 342
inch, which is 0*038 hich less than the average for the pre-
ceding eight years.

The mean weight of water in a cubic foot of air for the
quarter was 3*5 grains, which is 0*3 grain less than the average
for the preceding eight years.

The mean additional weight of water required to saturate a
cubic foot of air was 1*2 grain.

This value for the preceding eight years was I'l grain.

The mean degree of humidity in April was 0'864, in May
was 0*703, and in March was 0*7 15. The averages for the
eight preceding years were 0*802, 0*797, and 0*778.

The mean readiiig of the barometer at Greenwich in January
was 29517 inches, in February was 29*766 inches, and in
March was 29*868 inches. These values are respectively 0*215
inch less, 0*022 inch less, and 0080 inch greater than the
averages of the same montiis for the preceding eight years.

The average weight of a cubic foot of air under the average
temperature, humidity and pressure, was 534 grains ; the
average for the eight preceding years was 535*4 grains.

The rain fallen at Greenwich in April was 2*2 inches; in
May was 3*9 inches; and in June was 0*2 inch. The amount
for the quarter was 6*3 inches ; the average amount for the
preceding eight years was 4*74 inches. This excess of rain
was experienced only in the southern part of England. The
fall of rain between the latitudes of 52° and 53° was about the
average for this parallel. North of 53° the fall has been
small, and but little more than half the usual amount.

The horizontal movement of the air has been less than usual ;
its direction is uncertain ; observers in the same locality have
deduced the average direction differently*.

* Within ihc last few weeks a system of daily returns of the direction
of the wind, taken simultaneously at many different places in England, the

1 4-0 Mr. J. Glaisher's Remarks oti the Weather

The average daily ranges of the thermometer in air, at the
height offour feet, were 16°-0, ]6^-3, and 20°-6. The average
ranges of these three months from the observations of the
eight preceding years, were 16°-8,19°*2, and 19^*2 respectively.

The readings of the thermometer on grass in April was at
and below 32° on nineteen nights, the lowest was 19 ; between
32° and 40° on eight nights, and above 40° on three nights.
In May the lowest reading was 26 '7; and the readings were
below 32^ on four nights ; between 32° and 40° on seven
nights; and above 40° on twenty nights. In June the read-
ing was 32° on one night; at and below 40° on nine nights;
between 40° and 50^ on eighteen nights; and above 50° on
one night.

At St. John's Wood the lowest reading of a thermometer
with its bulb placed in a parabolic reflector and fully exposed
to the sky, was 20°-2 in April, 27°-2 in May, and 31°*^in June.

At Cardington the reading of a thermometer on grass was
less than 32° on eight nights in June; the lowest reading was
26°-5.

At Wakefield, on June 12 and 13j water exposed to the
sky wasirozen on both nights.

At Whitehaven the month of June was unusually cold, and
vegetation was subjected to very low temperatures at night; a
thermometer placed on grass on a layer of wool frequently fell
many degrees below the freezing-point, and on two nights it
fell to 25°. Ice was seen on several mornings, and snow fell
amongst the mountains on the 3rd, a phfienomenon which has
not been witnessed in June since the year 1827.

During the month of June the readings at night were un-
usually low, even the temperatui'e of the air in many places
nearly fell to 32°, and actually did so in York, which was a
point lower than the observer Mr. Ford had ever before seen
in June.

There were four exhibitions of the aurora horealis during
the quarter ending June 30, 1849 ; it occurred on May 31, and
was seen at Stone; on June 15 at Stone; on June 26 at La-
timer, auroral streamers passed from S.W. nearly across the
zenith to the horizon in the N.E. ; and on June 30, at Latimer,
some beautiful auroral flashes were seen at 10^ 30"" p.m.

Thunder-storms occurred on April 28 and on May 2 at
Stone; on May 3 at Uckfield, Stone, Saffron Walden, and
Nottingham; on May 4 at Uckfield; on May 14 at Saf-

soiitliof ScotlanJ, and which it is to be hoped will soon emljrace some por-
tions oflreland, have been organized. All the stations from which returns
are now sent, 1 have visited and given instructions to the observers so as to
ensure accuracy. The observations are publi.->hed daily in the Daily News
newspaper. If this system be continued some time valuable information
will be collected.

I

during the Quarter ending June 30, 1S4'9. 141

fron Walden, Holkham, and Nottingham; on May 17 and
18 at Leicester and Nottingham ; on May 22 at Nottingham ;
on June -t at Uckfield and Nottingham ; on June 5 at Nor-
wich ; on June 6 at Holkham ; on June 7 at Helston ; on June
9 at Helston; on June 16 at Hartwell ; and on June 17, 18
and J 9, at Helston.

Lightning was seen but thunder was not iieard on Miiy 3,
at Uckfield; on May 4- at Uckfield, Nottingham and Stone;
on May 14 at Leicester; on June 3 at Uckfield; on June 4
at Wakefield ; on June 5, 7 and 9, at Helston ; and on June
12 at Nottingham.

Thunder was heard but lightning was not seen at Wakefield
on April 6 ; at Exeter on May 5 ; at Uckfield on June 4 and
8; at Hartwell on May 3, 14, 15, 18, and June 6; and at
Norwich on June 28.

Hail fell at Hartwell on April 2; at Manchester on April
11 ; at Truro and Saffron Walden on April 13 ; at Hartwell
on April 14; at Truro and Saffron Walden on April 17 and
18; at Tniro on the 19th; at Truro, Saffron Walden, Hart-
well and Holkham on April 20; at Holkham on April 21;
at Fxeter on May 5; at Holkham on May 14; at Helston
on June 7 and 9; at Hartwell on June 16; and at Helston
on June 17 and 19.

Snow fell at various places on April 13, 16, 17, 18, 19, 20,
and 21.

Solar halos were seen at different places on April 2, 8, 25,
27; May 12, 13, 19, 29, 30, 31 ; June 15, 18, 23 and 24.
This unusual number of solar halos indicates a very unusual
prevalence of the cirrostratus cloud during the day. A lunar
halo was seen at Hartwell on May 31.

The reading of the barometer on April 1 was 29'4 inches;
it decreased to 29 3 inches on the 2nd, and increased to 29'55
on the 3rd. On the 4th it decreased quickly, and was 29*28
on the morning of the 5th. From this time to the 8th the
change of readinfj was small. On the 9th the reading was
29*34; it began to increase, and was 29*71 on the morning of
the 12th, when it began to decrease rapidly, and it was 29*09
during the afternoon of the 13th. On the 14th it increased
slowly, and on the 15th it was 29*6. The reading continued
about this value till the morning of the 18th, when it was 29*77;
it then began to decrease quickly, and on the morning of the
19th was 29*08, which was the lowest during the month.
During th^ remainder of the 19th and till the evening of the
21st the reading increased, and was 29*83 at the latter time.
The reading decreased on the 22nd, and was 29*48 on the
23rd. From the 24th to the 28th it was about 296, and then
increased to 30* 15 on the 29th, and to 30*18 on the morning

142 Mr. J. Glaisher's Remarks on the Weather

of the 30th. This reading was the highest in the month ; but
it soon again decreased, and before midnight descended below
30 inches. The range during this month was 1*09 inch.

On May 1 the reading was 2992, which decreased to 29*63
on the 5th; increased to 29" 86 on the 9th; it then decreased
to 29*72 by the evening of the 1 Ith, increased to 30*09 by the
12th, and decreased to 29*18 on the i7th ; this was the lowest
reading during the month. The reading, with slight excep-
tions, increased till the 24th, when it was 30*07; it then de-
creased and increased alternately, but the changes were small
till the end of the month. The highest reading was 30*08,
and it took place on the 29th. The range within this month
was 0*90 inch.

During the month of June the changes of reading were
small. The lowest reading was 29*63 on the 16th, and the
highest was 30*06 on the 22nd. The range therefore within
the month was 0*43 inch only.

The following are the agricultural reports with which I have
been favoured.

At Guernsey, the particulars having been furnished by Dr.
Hoskins, F.R.S.

In April, from the 10th to the 20th, there were cold winds
with showers of hail and sleet which checked the forward ve-
getation and destroyed crops of early potatoes. In May, fogs
with high temperatures were prevalent, and there were frequent
light gales and heavy showers of rain. Vegetation generally
recovered from the checks it received in April ; grass and other
crops were luxuriant, asparagus fine and abundant; wall-
fruit, horse-chestnuts, sycamores, and other trees of early
foliage, in exposed situations were much injured by blight.

In the early part of June there were frequent thunder-storms,
with fine sultry weather. Towards the end of the month fogs
were prevalent; there was an unusual prevalence of easterly
winds ; strawberries were abundant and well-flavoured, crops
of grass luxuriant, as well as other vegetation, notwithstand-
ing the paucity of rain.

At Uckfield, the particulars having been furnished by C. L.
Prince, Esq.

On April 19 very heavy rain fell early in the morning; at
3 P.M. on this day the wind shifted suddenly to N.E., and a
severe gale and heavy snow continued for eight hours ; as the
temperature of the air at the time fell to 32°, it almost de-
stroyed the gooseberry bloom, as well as that of the early
cherries. The wall-fruit was much injured, and in some places
the trees were killed, being cased with ice during the night,
and thawed suddenly by the sun on the 20th.

At Leeds, by Charles Charnock, Esq.

during the Quarter ending June 30, IS^Q. 1 4- 3

The cold and dry parching winds are seriously affecting
spring-sown crops on dry soils. The Swedish turnips are a
very patchy crop and have been resown in many places.
Barley and oats are short. Beans are affected with the Aphis.
Wheat on strong soils is very deficient, but on light soils it is
better. Potatoes have been much cut down by the white
frosts. On the whole the country is suffering much from the
want of rain. Cattle and sheep are healthy. Employment
for agricultural labourers is scarce, and as a body they are
suffering severely.

Hampshire, the particulars having been furnished by John
Clark, Esq. of Timsbury Farm, near Romsey.

The prospect for those farmers who have been in positions
to do justice to their operations, is cheering; every crop pro-
mises to be abundant. The hay harvest is nearly completed,
and in the most satisfactory manner. There have however
been many instances of the truth of the old saying, that more
hay is spoiled in fine weather than in catching seasons. The
vigorous and thick growth of the grass has required more
time to perfect than many farmers have allowed, and injury
has resulted.

The crops on badly-farmed lands are thin and poor, oats
are generally indifferent. The season for turnip tillage has
been all that could be desired, excepting on neglected stiff
lands, and there the needful pulverization of the land has not
been obtained for want of moisture. Now, July 6, every de-
scription of root-crop is languishing for want of rain. The
turnip-fiy has not been so troublesome as in past seasons.
Potatoes appear generally healthy. There is every prospect
of a full average yield of wheat, and should there be a con-
tinuance of fine weather, it will be gathered much earlier than
usual.

At Stonyhurst, the particulars having been furnished by the
Rev. Alfred Weld, F.R.A.S.

The lambing season began in this neighbourhood on the
23rd of March, and continued three weeks; there were several
losses in the country owing to the severity of the weather.
During April and the early part of May the weather was re-
markably dry and unfavourable to the growth of grass; this,
added to the general dryness of the season, has caused the
hay crop to be very late. The season for sowing was very
favourable; oats were sown first on March 23, and now make
a fine show. Early potatoes planted before April 1 are grow-
ing well and without any signs of disease. The crop is very
abundant, frequently producing 20 to 30 to a root. Later
potatoes planted in April escaped the effects of thefrosts, which
are said to have destroyed a considerable portion of th' crops

144 Mr. J. Glaislier's Remarks oti the Weather

in the neighbourhood of Manchester and Liverpool. Oats
have been infested with charlock to a great degree. The
sowing of beet began May 5 ; the crop is healthy and forward.
Turnips planted about May 10 are very luxuriant and pro-
mising ; no fly has appeared. Sheep-washing took place about
May 21, which is about the usual time in this part of the
country. Some ewes shorn on June 14 died from cold. On
June 9 vegetation appeared to stop from the cold weather,
which continued till the 15th, The showers which brought
on the green crops so well were not sufficient for the grass,
which is still very short, though full in the root. The hay
season generally begins in this part about June 26, whereas
this year (now July 8) none is cut except one or two small
patches ; the grass is still growing fast, and promises to be an
abundant crop. Wheat has been in ear about twelve days;
oats are just opening out.

Nottingham, the particulars furnished by E. J. Lowe, Es(] ,
F.R.A.S.

Wheat, barley and oats look well; the grass crops are heavj,
and potatoes promise well. The frost of April 18 did great
injury to fruit.

The monthly values of the several subjects of research ap-
pear in the Registrar-General's Quarterly lleport; the quar-
terly values are shown in the subjoined table:—

The mean of the numbers in the first column of this table is
2961 8 inches, and this value may be considered as the pres-
sure of dry air for England during the quarter ending June 30,
1849.

The mean of tiie numbers in the second column, for Guern-
sey and those places situated in the counties of Cornwall and
Devonshire, is 52°"0; for those })laces situated south of latitude
of 52°, including Chichester ami Hartwell, is 52°-l ; for those
places situated between the latitudesof 52"^ and 53°, including
Saffron Walden and Leicester, is 50^*0 ; for those places
situated between the latitudes of 53° and 54°, including Derby
and York, is 49-9 ; and for Whitehaven and Newcastle is
49°*8. These values may, be considered as those of the mean
temperatures of the air for these parallels of latitude during
the quarter ending June 30, 1849.

The average daily range of temperature in Cornwall and
Devonshire was 14°'8; at Liverpool and Whitehaven was
12°-1; south of latitude 52° was 19°-y; between the latitudes of
52° and 54° wasl7°'6; and at Whitehaven and Newcastle was
17°-6.

The greatest mean daily ranges of the temperature of the air
took place at St. John's Wood, Latimer, Aylesbury, and
Beckington : that at St, John's Wood is very large; is it right ?

during the Qiiarter ending June SO, 18-1-9. 145

and the least occurred at Truro, Liverpool, Guernsey, and
Whitehaven.

The highest thermometer readings during the quarter were
88' at Southampton, 86° at Walworth, 85" at St. John's
Wood and at Latimer. The lowest thermometer readings
were 24° at Leicester, 24°'3 at Highfield House, and 25° at
Uckfieid and at Aylesbury. The extreme range of tempe-
rature of the air during the quarter in England was therefore
about 61°, considering the true extremes as 24° and 85°.

The average quarterly range of the reading of the thermo-
meter in Cornwall and Devonshire was 43'*0 ; at Liverpool
and Whitehaven was 4l°*5; south of latitude 52° was 65°'5^
and north of 52° was 51°-1.

The mean temperature of the dew-point in Cornwall and
Devonshire was 43°'7 ; south of latitude 52° was 43°*5; be-
tween 52° and 53° was 42°'2, and north of 53° was 43°-6.

The amount of cloud seems to have been less than usual.

Rain has fallen on the greatest number of days at Hartwell,
Wakefield, and Cardington. The average number at these
places was 54. It fell on the least number of days at Maiden-
stone Hill, Hereford and Beckington, and the average num-
ber at these places was 33. The stations at which the largest
falls have taken place are Truro, Newcastle and Helston.
The smallest falls occurred at York, and generally in the north
of England. The average fall in the counties of Cornwall and
Devonshire was 8'1 inches ; south of latitude 52° was 6*4
inches; between the latitude of 52° and 53° was 7'4 inches;
between 53° and 54° was B'5 inches ; and at Newcastle and
Whitehaven was 7*8 inches.

The numbers in the columns 1 5 to 18 show the mean values
of the hygrometrical results; from which we find that —

The mean weight of vapour in a cubic foot of air at all
places (excepting Cornwall and Devonshire) in the quarter
ending June 30, 1849, was 3*5 grains.

The mean additional weight required to saturate a cubic
foot of air in the quarter ending June 30, 1 849, was 0*9 grain.

The mean degree of humidity (complete saturation = 1) in
the quarter ending June 30, 1849, was 0*776.

The mean amount of vapour mixed with the air would have
produced water, if all had been precipitated at one time on
the surface of the earth, to the depth of 4'2 inches.

The mean weight of a cubic foot of air under the mean
pressure, temperature and humidity, was 532 grains at the
average height of 170 feet

And these values for Cornwall and Devonshire were 3*5
grains; 0*9 grain ; 0*749 ; 43 inches ; and 534 grains, at the
average height of 120 feet.

l*hil, Mag. S. 3. Vol. 35. No. 234. Aug. 1849. L

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[ 147 ]
XX. Proceedings of Learned Societies.

ROYAL SOCIETY.

[Continued from p. 71-]

March 29, "/^ ENER AL Methods in Analysis, for the resolution

1849. VJ of Linear Equations in Finite Differences and
Linear Differential Equations." By Charles James Hargreave, Esq.,
LL.B., F.R.S. &c.

The investigations presented in this paper consist of two parts ;
the first offers a solution, in a qualified sense, of the general linear
equation in finite differences ; and the second gives an analysis of
the general linear differential equation with rational factors, so far
as concerns its solution in series.

The author observes that there does not at present exist any ge-
neral method of solving linear equations in finite differences of an
order higher than the first ; and that with reference to such equa-
tions of the first order, we obtain insufficient forms which are intel-
ligible only when the independent variable is an integer. It is in
this qualified sense that the solutions proposed in this paper are to
be taken ; so that the first part of these investigations may be con-
sidered as an extension of this form of solution from the general
equation of the first order to the general equation of the wth order.

In the second j)art, the author points out a method by which the
results of the process above indicated may be made to give solutions
of those forms of linear differential equations whose factors do not
contain irrational or transcendental functions of the independent
variable, or contain them only in an expanded form.

This object is effected by means of the theorem, relative to the
interchange of the symbols of operation and of quantity, propounded
by the author in a former memoir published in the Philosophical
Transactions (Part I. for 1848, p. 31). It is one of the properties
of this singular analytical process that it instantaneously converts a
linear equation in finite differences into a linear differential equation ;
so that whenever the former is soluble, the latter is soluble also,
provided the result be interpretable ; a condition satisfied when the
functions employed are rational algebraical functions.

Notwithstanding the qualified character of the solutions previously
obtained forlinearequations in finite differences, the solutionsobtained
from them by this process are free from all restriction. The solutions
in series can be written down at once from the equation itself, inas-
much as each series has its own independent scale or law of relation ;
and no difficulties arise from the appearance of equal or imaginary roots
in the equation determining the incipient terms of the series. These
circumstances do indeed cause a certain variation of form; but they do
not compel us to resort to any special process in each individual case.

The perfect separation and independence of the scales, or laws of
relation of the series enables the author to discuss the characters of
the series with reference to their convergency or divergency, and to

L2

1 48 Royal Society.

classify these equations into sets having peculiar and distinguishing
properties in regard to this subject.

The first set includes those equations whose solutions can always
be found in convergent series of ascending powers of the independ-
ent variable ; and if in such case the equation be solved in series of
descending powers (which can be done by this process), those series
are certainly always divergent.

The distiiiguishing marks of this class of equations are, — that the
factor of the highest differential coefficient contains one term only;
and that (the terms being arranged in an ascending order) when
this term is x^, the factor of the next differential coefficient must
not contain a term lower than xP-'^, the next riot lower than x^~^y
and so on to the end.

The second set includes those equations whose solutions can always
be found in convergent series of descending powers of the independ-
ent variable ; and if in such case the equation be solved in series of
ascending powers, they are always divergent.

The distinguishing marks of this class of equations are, — that the
factor of the highest differential coefficient contains one term only ;
and that when this term is x'^, the next factor must stop dXxp-^, the
next at x''~'^, and so on to the end.

The third set includes equations whose solutions can be found in
series oi ascending powers which for some values of the independent
variable are convergent, and for other values divergent ; and whose
solutions can also be found in series of descending powers which are
divergent for all values for which the other series are convergent, and
convergent for all values for which the other series are divergent.

The distinguishing marks of this class of equations are, — that the
factor of the highest differential coefficient contains two terms only,
and that with reference to the first of such terms the equation is
under the restriction mentioned with regard to the first set, and that
with reference to the second of such terms it is under the restriction
mentioned with regard to the second set.

The fourth set includes equations whose solutions are or may be
divergent for some values of x, both in the ascending and descend-
ing series. In some cases, the ascending series is necessarily diver-
gent, and the descending series convergent or divergent according to
the value of x ; in other cases, the descending series is necessarily
divergent, and the ascending series convergent or divergent accord-
ing to value ; and in the remaining cases, both series are convergent
or divergent according to value, but not so as to be necessarily com-
plementary to each other in this respect.

The distinguishing marks of this class are, — that the first factor
may contain more than two terms ; and that either the restriction of
the first set is transgressed with reference to the highest term, or the
restriction of the second set is transgressed with reference to the
lowest term. In this set the divergency arising from value is of a
finite character; and, as the series approach without limit to ordi-
nary recurring series, there is a probability that the passage from
convergency to divergency is not attended with danger.

Royal Society. 149

The fifth set includes equations whose solutions, whether in as-
cending or descending series, are always necessarily divergent.

The distinguishing mark of this class is, that it transgresses both
the restrictions to one or other of which the last set is subjected. In
this case the divergency is infinite, and appears to be of an unma-
nageable character.

The analogy of the process leads to a presumption, that in all
cases of divergency, above referred to, the corresponding convergent
solutions are in series infinite in both the ascending and descending
directions.

The author observes in conclusion, that the inverse calculus of
the process here developed may be employed for the discovery of
the generating functions of series whose laws of relation are given.

April 26. — "A Report upon further Observations of the Tides of
the English Channel made by order of the Lords Commissioners
of the Admiralty in 1848, with remarks upon the Laws by which
the Tidal Streams of the English Channel and German Ocean appear
to be governed." By Captain F. W. Beediey, R.N., F.R.S. Com-
municated by the Lords Commissioners of the Admiralty.

The author commences this report by observing, that the result
of the observations upon the tides in the English Channel, made in
the course of the summer of 1848, had confirmed in a satisfactory
manner the view he had taken of the tidal phenomena of the chan-
nel, in the report communicated to the Royal Society last year, and
printed in the Philosophical Transactions (Part L 1848), namely,
that there is a meeting and a separation of the streams between
Alderney and the Start : that the whole space between the Start
and SciHy is under the joint influence of the channel and offing
streams : that from the vicinity of the Start to the vicinity of Hast-
ings the stream runs true up and down the channel ; and moreover
that this stream throughout turns nearly simultaneously with the
time of high and low water on the shore at the virtual head of the
tide, which he places in the vicinity of Dover ; and lastly, that the
streams which meet off the Start are turned down into the Gulf of
St. Malo, and vice versa.

He then takes a comprehensive view of the tidal system of the
English Channel and German Ocean together, and considering them
as one great canal open at both extremities to the free admission of
a great tidal wave, which might be supposed to meet and form a
combined or stationary wave (art. 187, Encyclopedia Metropolitana),
he infers that in such a case, there ought to be in the eastern half
of such a canal, a recurrence of the phenomena which had been
found to exist in the western half. He proceeds to explain that,
from a valuable series of observations in the German Ocean by Cap-
tain Washington, R.N., and other authorities, it does appear that,
inverting the direction of the stream, there is a correspondence of
phenomena in almost every respect: that the offing and channel
streams meet off Lynn, as off the Gulf of St. Malo, at the same hours,
and at the same distance nearly from the virtual head of the tide :
that the phase of the tide at Lynn corresponds with the phase of the

1 50 Royal Society.

tide at Jersey : that there is an increased rise there also ; and that
from the meeting of the tides off Lynn to the meeting of the streams
off Dover, there is, as in the former case, a stream which turns nearly
simultaneously with the high and low water on the shore at Dover ;
the incoming and outgoing streams coinciding with the rising and
falling water there ; and that there is, in fact, a complete identity of
tidal phenomena in both parts of the supposed canal ; of this an
illustration is given in two plans.

The author states that the meeting of the waves which enter the
canal at opposite points does not occasion a stationary point of per-
manent slack-water, but one wave alternately prevails, so that the
point of slack- water oscillates between Ramsgate and Hastings nearly,
and occasions an inversion of the stream at about two hours before
that of the true stream of the channel. He thinks it convenient for
the purposes of navigation to consider this an intermediate stream,
although in reality it is only a shifting of the place of the meeting
and divergence of the opposite channel streams. To illustrate this
part of the paper a table is given, in which the courses of the streams
in various compartments of the supposed canal are given at every
hour of the tide.

The author thinks this system of tides sufficiently established for
the purposes of navigation, but with regard to the perfectly simul-
taneous motion of the stream throughout the stationary wave, he is
of opinion that nothing but simultaneous observations will be con-
sidered satisfactory to science upon such a point, and these he hopes
will be supplied by the observations of the ensuing summer.

The advantage of referring the motion of the stream to a standard
such as that of the Dover tide-table will, it appears, be sensibly felt
by the mariner, who will now have his course through the moving
waters of the channel rendered simple and plain, instead of being
perplexed with unsatisfactory references, and with calculations which
in too many instances, it is believed, have caused the set of the tide
to be wholly disregarded.

The want of a standard to which desultory observations, made in
various parts of the channel, could be referred, the author believes
to have been the occasion of several erroneous impressions of a some-
what dangerous tendency to navigation. As such he considers the
following : — that the tide in all parts of the channel partakes of a
rotatory motion and is never at rest, and that a ship's reckoning will
never be far out in consequence, as she will never be carried far in
one direction : that a vessel arriving off the Start at low water
could, by sailing seven or eight knots an hour, carry ten or eleven
hours favourable tide to Beachy Head : that in the German Ocean
the stream sets north-east on one side, whilst it is running south-
west on the other : that there is a tide and half-tide in the channel,
so that when the stream has done in shore, by standing out, a ship
will carry the stream three hours longer, or nine hours in one direc-
tion : and lastly, that the stream runs strongest at high and low veater
throughout the channel, and is ujotionless at half-tide.

These impressions do not appear to be justified by the observa-

Royal Society. 151

tions. The stream when not diverted by rivers or estuaries appears
to run true up and down the channel, and from side to side nearly ;
between the Start and Hastings, in the English Channel, scarcely
varying a point for nearly five hours ; and in the German Ocean for
about four hours ; the varying of the stream there being due, in the
author's opinion, to the influence of the Thames and the rivers of
Holland. As the stream turns nearly with the high and low water
on the shore at Dover, there cannot be nine hours' current in one
direction. With regard to the time at which the stream attains its
greatest strength, he states that all the observations agree in fixing
it at about half-tide (Dover).

The erroneous impressions above mentioned, the author considers
have arisen from the times of the observations when made having
been referred to the times of high water at places differing two or
three hours from the time of high water at the head of the wave, or
from an early popular opinion that the turn of the stream in the
offing coincides with the rise and fall of the water on the shore.

The paper concludes with some remarks on the forms of the tide-
wave between Cromarty and the Land's End, which are exhibited in
two plans at every hour of the tide, obtained from a combination of
the ranges and establishments of Dr. Whewell with those of M.
Chazallon ; and attention is particularly drawn to the relative lengths
of the stationary wave and the waves by which it is generated ; the
former wave being only half the dimensions of the latter. These forms
are exhibited on a reduced scale, but much exaggerated in height,
and afford a comparison between the curve assumed by the stationary
wave and that which the waves would have assumed had they rolled
on in an uninterrupted course.

May 3. — " On the Reduction of the Thermometrical Observa-
tions made at the Apartments of the Royal Society from the year
1774 to 1781, and from the year 1787 to 184'3." By James Glaisher,
Esq. of the Royal Observatory, Greenwich. Communicated by John
Lee, Esq., LL.D., F.R.S. &c.

In this paper the author states that he has examined all the ther-
mometrical observations which have been made at the Apartments of
the Royal Society, with the view of ascertaining whether the diurnal
variations at different epochs were in accordance with those which
he had determined from the Greenwich observations, and which are
contained in his paper published in the Philosophical Transactions
for 1848. The result of this investigation was, that the corrections
contained in the tables in his former paper were applicable to the
observations of all the years since 1774.

The author is led from these examinations to the conclusion, —
1st, that the instruments used have been uniformly good; 2ndly,
that the observations have been faithfully recorded as read from the
instruments ; 3rdly, that the readings have been taken with great care
with respect to the times stated; and lastly, that the observations
were well worth the necessary labour of reduction. He finds, how-
ever, that some of the more recent observations of the self-register-
ing instruments are liable to some uncertainty.

1 52 Royal Society.

Having satisfied himself that the observations were well worth
any amount of labour that might be bestowed on them, the author
was anxious to reduce them to a useful form, but, in consequence of
the great amount of work that would be required for the reduction
of so extensive a series, he for some time hesitated to enter upon
this labour. Finding however that there was a demand for the re-
sults of trustworthy observations extending backwards many years,
and having, besides, the hope of connecting the Greenwich series of
observations with these, he determined to perform the work. He
states that the mean ten)perature of every month was determined in
the first instance from the observations which had been made during
the day, and secondly, from the observations of the self-registering
instruments. Tables are appended to the paper showing the monthly,
quarterly and yearly mean temperatures, with those of groups of
years, and other tables exhibiting the departure of every individual
result from the mean of all.

The author concludes by stating, that hitherto the mean tempera-
ture at Somerset House has been estimated a great deal too high.
He does not here enter into the investigation as to whether the tem-
perature as now determined is too high for the geographical position
and elevation of Somerset House, but proposes to do so, in a paper
he is preparing with the view of connecting the Somerset House
with the Greenwich series, and of bringing up all the results to the
present time. He hopes also, at some future time, to present results
from the barometrical observations arranged in a similar manner.

May 24. — 1. An appendix to a paper " On the Variations of the
Acidity of the Urine in the State of Health" — " On the Influence of
Medicines on the Acidity of the Urine." Bv Henry Bence Jones,
M.D., M.A., F.R.S. &c.

The variations of the acidity of the urine in the state of health
having been shown in the original paper, and the effect of dilute
sulphuric acid also traced ; in this appendix the influence of caustic
potash, of tartaric acid, and of tartrate of soda, on the acidity of the
urine is determined.

One ounce of liquor potassae, specific gravity 1072, was taken in
distilled water, in three days. It hindered the acidity of the urine
from rising long after digestion to the height to which (from com-
parative experiments) it otherwise would have done ; but it by no
means made the urine constantly alkaline; nor did it hinder the
variations produced by the state of the stomach from being very
evident.

354 grains of dry and pure tartaric acid dissolved in water were
taken in three days. The conclusion from the observations is that
this quantity increased the acidity of the urine, but during that time
it did not render the effect of the stomach on the reaction of the
urine less apparent than when no acid was taken ; and therefore,
that this quantity of tartaric acid, during this time, does not produce
iSo much effect on the reaction of the urine as the stomach does.

Tartrate of potash in large doses produces the most marked effect
on the alkalescence of the urine. 120 grains of pure dry tartrate

lim^al Society, 153

of potash dissolved in four ounces of distilled water made the urine
alkaline in thirty-five minutes. In two hours the alkalescence had
disappeared, but after the next meal the eifect of the tartrate of
potash was again apparent. 10 drachms of tartrate of potash taken
in three days produced but little, if any effect, on the acidity of the
urine twenty-four hours after the last dose was taken.

2. " On the direct production of Heat by Magnetism." By
W. R. Grove, Esq., M.A., V.P.R.S. &c.

The author recites the experiments of Messrs. Marrian, Beatson,
Wertheim and De la Rive on the phenomenon made known some
years ago, that soft iron when magnetized emitted a sound or musical
note.

He also mentions an experiment of his own, published in January
1845, where a tube was filled with the liquid in which magnetic
oxide had been prepared, and surrounded by a coil; this showed
to a spectator looking through it a considerable increase of the
transmitted light when the coil was electrized.

All these experiments the author considers go to prove that when-
ever magnetization takes place a change is produced in the molecu-
lar condition of the substances magnetized ; and it occurred to him
that if this be the case, a species of molecular friction might be
expected to obtain, and by such molecular friction heat might be
produced.

In proving the correctness of these conjectures difficulties pre-
sented themselves, the principal of which was that with electro-
magnets the heat produced by the electrized coil surrounding them,
might be expected to mask any heat developed by the magnetism.
This interference, after several experiments, the author considers
he entirely eliminated by surrounding the poles of an electro-magnet
with cisterns of water, and by this means and by covering the
keeper with flannel and other expedients, he was enabled to produce
in a cylindrical soft-iron keeper when rapidly magnetized and de-
magnetized in opposite directions a rise of temperature several degrees
beyond that which obtained in the electro-magnet, and which there-
fore could not have been due to conduction or radiation of heat from
such magnet. A series of experiments is given with this apparatus.

By filling the cisterns with water colder than the electro-magnet,
the latter could be cooled by the water while the keeper was being
heated by the magnetization.

The author subsequently obtained distinct thermic effects in a
bar of soft iron placed opposite to a rotating permanent steel mag-
net, using a delicate thermo-electrical apparatus placed at his disposal
by Mr. Gassiot.

To eliminate the effects of magneto-electrical currents, the author
then made similar experiments with non-magnetic metals and with
silico-borate of lead, substituted for the iron keepers, but no thermic
effects were developed.

He then tried the magnetic metals nickel and cobalt, and obtained
thermic effects with both, and in proportion to their magnetic in-
tensity.

154? Intelligence and Miscellaneous Articles.

Some questions of theory suggested by the above experiments
and relating to the rationale of the action of what are termed ' the
imponderables' and to terrestrial magnetism, are then briefly dis-
cussed, and the author concludes by stating that he considers his
experiments prove satisfactorily, that whenever a bar of iron or
other magnetic metal is magnetized, its temperature is raised.

XXI. Litelligence and Miscellaneous Articles.

ON THE PREPARATION OF PURE OXIDE OF COBALT.
BY M. LOU YET.

n| '^HE author observes that chemists are generally aware that no-
J- thing is less easy than to separate oxide of cobalt from the iron
and nickel which it contains ; on this account the oxide of cobalt is
rarely met with in commerce perfectly free from all traces of these
metals.

Among the methods which have been proposed to obtain from
cobalt ores the oxide perfectly free from iron and nickel, M.Liebig's
appears to have been preferred. This process, which depends chiefly
on the property of suljjhate of cobalt to resist a red heat, whilst the
sulphates of iron and nickel are totally decomposed, may undoubt-
edly give good results, as applied to ores ; but the author states that
his researches in all other cases have failed to produce perfectly pure
oxide of cobalt.

The author found that although sulphate of iron, when exposed
alone to a red heat, is perfectly decomposed, yet when mixed with
a large quantity of sulphate of cobalt, it sustained it without being
decomposed, and consequently without being rendered insoluble ;
the heat was very great, and kept up for several hours. If a mixture
containing cobalt, but no arsenic, be treated according to M. Liebig's
process, the iron, not being converted into an insoluble arseniate,
remains in the mass partly in the state of sulphate. This takes place
with zafi^re, an arsenical ore of cobalt which has been roasted, and
from which the arsenic has consequently been expelled. It results
from what is above stated, that the sulphate of iron formed, partially
resists the action of the heat, and consequently that the cobalt even-
tually obtained contains iron, though completely free from nickel.

Although processes are already known by which cobalt and iron
are separated without much difficulty, the author states that one
which he has discovered is so simple, and its employment so certain,
that he thinks in making it known he may render service to the arts
which include the use of pure oxide of cobalt.

This 'process depends on the diff'erence which exists between the
affinities of oxide of cobalt on one hand, and on the other of the
protoxide and sesquioxide of iron for acids ; a diff'erence which is
highly advantageous to the first of these compounds. Take a solu-
tion of sulphate of cobalt, containing a certain quantity of sulphate
of iron, and add to this gelatinous hydi'ate of cobalt at least equiva-
lent to the oxide of iron contained in the sulphate ; heat the mixture

Intelligence and Miscellaneous Articles. 155

to ebullition for some time ; the violet colour of the hydrate of cobalt
will soon disappear, and it will be replaced by a precipitate of a dirty
yellow colour. In this case the hydrate of cobalt decomposes the
sulphate of iron, is substituted for the proto- or sesquioxide of iron,
which it renders insoluble, and precipitates in the state of hydrated
sesquioxide; this hydrate is necessarily mixed with a small quantity
of hydrate of cobalt, which should be used in excess, in order to be
certain of the complete precipitation of the oxide of iron. Nothing
remains to be done but to filter and wash the precipitate. The salt
of cobalt thus obtained yields no indication of the presence of iron
to the most sensible reagents. It yields, accordingly, no precipitate
whatever when, after having added hydrochlorate of ammonia to it,
it is supersaturated with great excess of ammonia.

For the sake of greater simplicity, a solution of carbonate of soda
may be employed instead of the hydrate of cobalt, and the mixture
digested at a boiling heat for some time ; in both cases the precipi-
tate will contain all the iron. [This appears to be identical with the
method proposed by Scheerer for separating iron from cobalt, de-
scribed in the Phil. Mag. for February 1840. — W. F.]

To recapitulate : it follows that in order to purify oxide of cobalt
it is sufficient to dissolve it in dilute sulphuric acid, to evaporate to
dryness, and calcine at a red heat, treating the mass with boiling
water, and adding to the solution either hydrate of cobalt or carbo-
nate of soda in the manner described. Sulphate of nickel appears
to decompose more readily than sulphate of iron, under the circum-
stances described ; when zafFre is treated according to M. Liebig's
process, it yields oxide of cobalt quite free from nickel, but contains
a large quantity of oxide of iron. — L'Institut, Juin 27, 1849.

ON ALUMINATE OF COBALT. BY M. LOUYET.

M. Louyet remarks it as well known, that alumina and the salts
of cobalt may combine in certain circumstances, and form a fine blue
colour. It is by this process that M. Thenard prepared the blue
which bears his name, by mixing certain proportions of alumina and
phosphate or arseniate of cobalt, and subjecting the mixture to a
long- continued calcination. All these substances are employed in
the gelatinous or hydrated state. As the precipitate formed by-
carbonate of soda in a mixture of alum and a salt of cobalt also yields
a blue compound by calcination, it has been inferred that the consti-
tuent elements of cobalt-blue were alumina and oxide of cobalt, so
combined that the compound may be considered as a salt, or an alu-
minate of cobalt.

The facts which M. Louyet has ascertained are, that the sub-
stance obtained by the mixture of gelatinous alumina and phosphate
or arseniate of cobalt, also in the gelatinous state, yields a blue when
subjected to a red heat. At this temperature the mixtures of gela-
tinous alumina and hydrated oxide of cobalt yields only blacks or
grays, whatever may be the proportions of the constituents. In order
that the alumina and cobalt may produce blue, the mixture must be
exposed to a temperature very near that of melting glass. It results

156 Intelligence and Miscellaneous Articles.

from this that the presence of certain fixed acids is favourable to the
combination of alumina with oxide of cobalt. These observations
explain the cause of failure which chemists occasionally incur, in
attempting to prepare Thenard's blue without employing phosphate
or arseniate of cobalt. — L'Institut, Juin 27, 1849.

DETECTION OF IODINE AND BROMINE.
BY M. ALVARO REYNOSO.

The method employed to ascertain the presence of these bodies,
when they exist as iodides or bromides, the author remarks, consists
in dissolving them in water, to add starch in the state of paste, or
aether and a few drops of solution of chlorine. The chlorine seizes
the metal combined with the iodine or bromine, and these bodies
colour the starch blue, or dissolve in the aether ; but iodine and
bromine having the property of combining directly with chlorine,
and of forming a chloride of iodine or of bromine, the chlorine,
in order to detect the presence of these bodies, ought not to be em-
ployed in excess ; because the chlorides of iodine or bromine are
decomposed by contact with water and produce hydrochloric acid,
and iodic or bromic acid without acting on the starch or the aether.

This experiment was very difficult to perform ; often, indeed,
these bodies could not be discovered, and this was supposed to be
owing to the above-described difficulty. Then the quantity of chlo-
rine was diminished, from the fear of exceeding the requisite pro-
portions, and it happened that the quantity of chlorine was not suf-
ficient to set the iodine at liberty. The manner in which the chlo-
rine was employed also increased this error ; in fact, it is well known
that a solution of chlorine is weakened by keeping, and that even-
tually its power is lost, in spite of every possible precaution. Thus
on pouring into a solution of an iodide or bromide a very small
quantity of aqueous solution of chlorine, it happened that the iodine
was not see free, and that all the chlorine was employed in forming
hydrochloric acid. This method, then, was not applicable to the
detection of small quantities of iodine or bromine, especially when
these bodies are mixed with substances capable of seizing the chlo-
rine. It was therefore desirable that the iodine or bromine should
be isolated by means of a body incapable of acting upon them, what-
ever might be its excess. Oxygenated water fulfills these conditions ;
it decomposes hydriodic or hydrobromic acid without at all acting
upon the iodine or bromine set free by it.

The following is the method of proceeding for iodine : a bit of
binoxide of barium is to be put into a small glass tube closed at one
end ; then are to be added to it distilled water, pure hydrochloric
acid, and paste of starch ; the operator is to wait till bubbles arise
to the surface, and then the iodide is to be added. A rose-blue
colour is immediately procured if the quantity of iodine is but small,
but of a deep blue if the quantity of iodine is considerable.

It is more convenient to operate on these conditions ; not only
considering them as manipulations which become very easy, but also
with regard to the success of the experiment. On this plan, the

Intelligence and Miscellarieous Articles, 157

requisite excess of oxygenated water is certain to be employed when
hyposulphites, sulphates, or sulphurets are present ; besides, the
hydrochloric acid employed in the preparation of the oxygenated
water, acts an important part, for it serves to set hydriodic acid free,

Ba0«+(C1H)« + IH, KO + HO=BaO, CIH + KO, C1H+2(H0) + I.

Although it is unquestionable that the hydrochloric acid, by react-
ing on the binoxide of barium, in the presence of water, produces
oxygenated water, the author was desirous of satisfying himself that
it was in fact HO^ which actually produced the result obtained ; for
this purpose he substituted tartaric for hydrochloric acid, and ob-
tained the same result. M. Thenard had also described the decom-
position of hydriodic acid by pure oxygenated water.

When the iodides are mixed with chlorides, sulphurets, sulphites or
hyposulphites, the process is equally correct ; only, as by the action
of hydrochloric acid on the sulphuret sulphuretted hydrogen is pro-
duced, which is decomposed by oxygenated water, and the hypo-
sulphites and sulphites are converted into sulphate by absorbing
oxygen, a larger quantity of oxygenated water is required than if
the iodide was pure.

The hyposulphites and sulphites, on becoming sulphates, produce
a precipitate of sulphate of barytes in the liquor ; this might delay
the action, if agitation were not employed to detach the sulphate of
barytes from the surface of the binoxide of barium : it is also a pre-
caution which ought always to be adopted to increase the production
of oxygenated water. By this process the presence of iodine is
readily detected in the urine of a patient taking 0*10 centigr. of
iodide of mercury morning and evening. In the same urine no
iodine could be detected by means of chlorine ; this is therefore a
case in which, notwithstanding every precaution, the iodine passed
undetected by chlorine.

This process detects the presence of iodine in the ash of sponge.
A drop of a solution of 0010 grm. of iodide of potassium dissolved in
a litre of water, produced, each time that it fell into the tube, a ma-
nifest blue colour at the surface. By agitation the blue colour dis-
appeared, and the liquor assumed a rose tint ; on adding another
drop, a fresh blue colour is obtained at the surface. This process,
therefore, very easily indicates less than -^^^ of iodide of potassium.
The process is the same for bromine, excepting that instead of starch
aether is employed; agitation is used, the bromine dissolves in the
aether, and it becomes of a more or less deep yellow colour accord-
ing to the quantity.

When, however, iodides and bromides occur mixed, they are de-
tected by adding an excess of starch and of aether. The iodine com-
bines with the starch, and the bromine, dissolving in the aether, rises
to the surface ; so that the blue colour is obtained below, and the
yellow tint high up. — Comptes Rendus, Avril 30, 1849.

158 Intelligence and Miscellaneous Articles.

ON THE CHEMICAL NATURE OF THE EGG

M. Barreswil has presented to the Academy of Sciences a memoir
in which he states that he has found sugar in the albumen of the egg,
and that the albumen is alkaline owing to the presence of carbonate
of soda ; he finds also that the yolk contains little or no alkali, and
that its emulsive property is derived from a product resembling the
pancreatic juice, which is not acid, and becomes so only by under-
going alteration. He further states that the acid reaction and pro-
perties of the gastric juice are owing to organic acid, and not to hy-
drochloric acid. — L'Institut, Juin 'JO, 1849.

ON THE FORMATION OF FATTY MATTERS IN VEGETABLES.

M. Blondeau de CaroUes remarks it as well known, that oleagi-
nous grains do not, in an early stage of their development, contain
any trace of fatty substances ; and that it appears evident that the
latter are formed from the substances originally entering into the
constitution of these grains. The author was desirous of determi-
ning which are the principles, the transformation of which gives rise
to the fatty bodies, and the mode in which it is effected.

The author especially studied the formation of oil in the olive.
This fruit, carefully analysed, yielded scarcely an appreciable trace
of nitrogen ; it was not therefore owing to the presence of vegetable
albumen or caseine, neutral nitrogenous bodies contained in oleagi-
nous grains, the transformation of which, according to MM. Liebig
and Dumas, is sufficient to explain the formation of fatty substances.

The elements of this transformation must then be sought for in a
body analogous in composition to fecula, sugar or lignin.

The analyses of olives, at first performed in an early state, and
afterwards as they approached maturity, showed that in the former
condition they contained no trace of oil ; but that from the moment
at which the oil began to appear till the fruit had attained its com-
plete development, the proportion of tannin, and especially of lignin
gradually diminished as that of the oily liquid increased.

From these circumstances the author concludes, that the formation
of oil in the olive is the result of the reciprocal action of tannin
and lignin, and experiment seemed to confirm this explanation :
some olives confined in a graduated receiver full of mercury disen-
gaged after a few days, pure carbonic acid gas, and the sides of the
receiver were covered with the [condensed ?] vapour of water.

The carbonic acid was four times greater in volume than that of the
olives from which it was produced ; and it could be formed only at
the expense of the elements contained in the fruit, the external air
being excluded.

The following formulae explain the phaenomena described in a
satisfactory manner : —

Lignin. Tannin. Oil. Carbonic acid. Water.

This explanation was verified by experiment.

Meteorological Observations. 159

The analyses of the oil extracted from olives which had served for
experiment gave the following results : —

Oil 0-361. Carbonic acid 1043. Water 0*377.

Carbon .... 78-661 According to the formula fC 76-05

Hydrogen.. 11-39 > C^e H^e O^ <j H 12-95

Oxygen .... 9-95 J there should be obtained |_0 11 00

100-00 10000

These numbers approach each other sufficiently near to admit the
formula as expressing one of the most curious transformations pre-
sented by organic chemistry. — L'Instiut, Juin 20, 1849.

METEOROLOGICAL OBSERVATIONS FOR JUNE 1849.

Chiswick. — June 1,2. Fine. 3. Fine: hazy : clear. 4. Very fine. 5. Sultry :
showery at night. 6. Uniformly overcast. 7. Fine. 8. Fine : overcast 9. Fine:
rather cold: overcast: clear. 10 — 12. Overcast. 13. Fine: cloudy: clear.
14. Fine : slightly clouded. 15. Dusky haze. 16. Overcast : fine. 17. Fine:
dusky haze. 18. Fine. 19. Slight rain. 20. Very fine. 21. Fine. 22,23.
Very fine. 24. Cloudless and very fine. 25. Overcast: very fine. 26 — 28.
Very fine. 29. Cloudy : rain. 30. Cloudy : clear and cold at night.

Mean temperature of the month 59°*SO

Mean temperature of June 1848 59 "58

Mean temperature of June for the last twenty-three years ... 60 '85
Average amount of rain in June 1*88 inch.

Bnstnn. — June 1. Cloudy. 2 — 4, Fine, 5. Cloudy: rain, with thunder and
lightning A.M. : rain P.M. 6 — 9, Fine. 10. Cloudy : rain early a.m. 11. Cloudy.

12. Cloudy: rain p.m. 13,14. Fine. 15. Fine: rain p.m. 16. Cloudy. 17,
18. Fine. 19. Fine : rain a.m. and p.m. 20. Fine. 21. Cloudy. 22. Fine.
23. Cloudy. 24. Fine. 25. Rain. 26. Fine. 27. Cloudy. 28, Fine. 29.
Fine : rain p.m, SO. Cloudy.

Apptegarlh Manse Dumfrien -shire. — June 1. Clear and bracing weather:
shower A.M. 2. Fine and growing : one shower p.m. 3,4. Fair and fine. 5.
Fair A.M. : one shower p.m. : electr. 6,7. Fair and fine. 8. P'air, but chilly
from N.E. 9. Fair : air highly electric : thunder. 10. Fair and very droughty.
11. Fair and droughty : getting cloudy. 12. Fair and droughty : cleared away.

13. Fair and droughty. 14. Fair and droughty, but getting cloudy. 15. Fair
and droughty : cloudy : thunder. 16. Slight shower : much thunder. 17. Again
droughty. 18, Cloudy : a few drops of rain. 19. Heavy rain, night : shower,
day. 20. Frosty during night : shower p.m. 21. A few drops : very high wind.
22. Rain at intervals. 23. Fair and dear. 24. Light rain : very mild. 25.
Cloudy A.M. : slightly showery. 26. Slight shower p.m. 27. Fine : warm : fair
all day. 28. Fair. 29. Rain p.m. , not heavy but soft. 30. Fair all day and
warm.

Mean temperature of the month 53°*3

Mean temperature of June 1848 55*7

Mean temperature of June for twenty-five years 56 'I

Rain in June for twenty years 3*16 inches.

Sandwich Manse, Orkney. — June 1 , 2. Bright : clear. 3. Bright : cloudy. 4.
Showers : cloudy. 5, 6. Bright : clear. 7. Hazy : clear. 8. Bright : clear.
9. Bright: snow-showers. 10. Cloudy. 11. Bright: clear. 12. Bright:
cloudy. 13,14. Bright: clear. 15. Cloudy. 16. Drizzle: rain. 17. Clear:
rain. 18. Rain. 19. Cloudy : damp. 2o! Cloudy : rain. 21. Rain : clear.
22. Cloudy. 23. Rain : cloudy. 24. Bright : clear. 25. Bright : rain. 26.
Fog: drizzle. 27. Showers : hazy. 28, 29. Bright : clear. 30. Bright : rain.

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THE
LONDON, EDINBURGH and DUBLIN

PHILOSOPHICAL MAGAZINE

AND

JOURNAL OF SCIENCE.

[THIRD SERIES.]

SEPTEMBER 1849.

XXII. On the Production of Lightning hy 'Rain.
By William Radcliff Birt*.

f\^ the 26th of July, IS-tQ, a severe thunder-stoiin,accompa-
^^ nied by the destruction of property and the loss of human
life, passed over the metropolis. About 1^' 30™ p.m. the clouds
towards the north-east presented a very dark and threatening
aspect; they assumed an inky colour, and the velocity of their
motion was very slow ; in fact the appearance noticed was
strikingly of that character which the writer has frequently
observed to precede a thunder-storm. On this occasion his
attention was more particularly directed to the connexion
between the electric discharge and the sudden gush of rain
that more or less accompanies it, with a view to illustrate the
question occurring in the Report of the Committee of Physics
approved by the President and Council of the Royal Society,
p. 46, " Is this rain a cause or consequence of the electric dis-
charge ?" t On the previous day, the 25th, about 3^ 50°* p.m.,
during a thunder-storm a sudden gush of heavy rain occurred,

* Communicatecl by the Author.

\ The paragraph runs thus : " There is one point to which we wish that
some attention might be paid, — it is the sudden gush of rain which is almost
sure to succeed a violent detonation immediately overhead. Is this rain a
cause or consequence of the electric discharge? Opinion would seem to lean
to the latter side, or rather, we are not aware that the former has been main-
tained or even suggested. Yet it is very defensible. In the sudden agglo-
meration of many minute and feebly electrified globules into one rain-drop,
the quantity of electricity is increased in a greater proportion than the sur-
face over which (according to the laws of electric distribution) it is spread.
Its tension therefore is increased,and may attain the point when it is capable
of separating from the drop to seek the surface of the cloud, or ofthe newly-
formed descending body of rain, which under such circumstances, and with
respect to electricity of such a tension, may be regarded as a conducting
medium. Arrived at this surface, the tension for the same reason becomes
enormous, and a flash escapes."

Phil. Mag. S. 3. Vol. 35. No. 235. Sept. 1849. M

162 Mr. W. R Birt on the Production of Lightning hy Rain.

which within two seconds, by estimation, was succeeded by a
vivid flash of lightning : the thunder occurred at a further
interval of some few seconds. From this it would appear,
provided the heavy rain fell over the entire space between the
place of observation and that of the electric discharge, that it
was not a consequence of that discharge, the gush occurring at
a sensible interval previous thereto. The setting in of the
storm of the 26th, about l'^ 45"^ p.m., again called the atten-
tion of the writer to this point ; and several flashes occurred
between 1^ 45°^ p.m. and 2^ 3"^ p.m. without being preceded
by a gush, although heavy rain more or less accompanied the
discharges, in one or two instances almost simultaneously or
immediately afterwards. At length, about 2^ 4'°^ p.m., a most
violent and very remarkable gush of rain occurred, which was
followed within one minute by a most vivid flash of lightning,
the thunder succeeding almost instantaneously. The windows
of the house in which the writer was observing the storm were
sensibly shaken, and portions of the mortar between the arches
over the windows and the frames thrust out, of course by con-
cussion. Within a minute or two after this discharge a par-
tial cessation of the heavy rain took place, but sudden gushes
occurred at short intervals within the next six or seven mi-
nutes ; they were, however, unaccompanied by lightning. At
the end of this period the atmosphere presented a very re-
markable appearance ; a perfect stillness characterized the air,
which possessed great transparency, so that the surrounding
objects were seen with very minute distinctness of detail. The
stillness and transparency during the time they continued,
riveted the observer to their contemplation. It appeared that
during this time the storm was hushed, and a calm of a rather
extraordinary character succeeded it, during which a rather
large break in the clouds was seen towards the south-east, and
the entire phaenomena at this time induced the idea that the
weather was clearing up. Within ten minutes, however, the
storm again burst forth; the lightnings played, the thunder
roared, and heavy rain, mingled with hail so thickly that com-
paratively near objects could scarcely be distinguished, fell in
torrents, and the writer observed during the remainder of the
storm four or five sudden gushes that were quickly succeeded
by lightning. On all these occasions he is quite certain that
the sudden gush of rain preceded the electric discharge. Of
all the discharges, which were very frequent, that at or near
gh 5m pjyi, appeared to the writer to be nearest his own locality;
the lightning appeared to him to be quite as, if not more, vivid
than that at any other discharge; and the interval between it
and the thunder was certainly the shortest, the thunder being

Mr. W. R. Birt on the Production of Lightning by Rain. 163

the loudest. Between 2*^ 0"* p.M.and2^15™p.M., according to the
concurrent testimony of several witnesses, and preceding the
precipitation of the hail nearly half an hour, a discharge struck
half-a-dozen houses, being Nos. 17 to 22 in West Street,
North Street, Whitechapel, between one-fourth and one-third
of a mile south of the writer's residence. The stroke appears
to have presented some phaenomena of an interesting and re-
markable character. Immediately behind and to the west of
the houses in question is situated a large open space of ground,
known as a Jews' burying-ground, in which is a piece of water
not far from the houses. The gable end of No. 22 faces the
west, the fronts of the houses the north, and their backs the
south ; the flues of No. 22 form part of the wall at the gable
end. At the front and between every alternate house is a
metallic spout, for the purpose of carrying off the water from
the roof; the water is received from the tiles in a leaden or
zinc gutter, which is in metallic communication with the spout;
but it does not appear that there is a metallic communication
between the gutters from house to house : these metallic spouts
are short, not in any case descending so low as the doors ;
they are replaced by wooden spouts, which convey the water
to the street. It appears that the stroke perforated one of the
chimney-pots of No. 22, descending the flue to the roof, which
it stripped of a great portion of the tiles*, and then passed to
the metallic spout in front, disrupting and tearing away the
lower wooden spout, a piece of which, seven feet in length, it
rent off and hurled with great violence into the back yard of
one of the opposite houses which abutted on the north side of
West Street : a great portion of the piece rent from the spout
was shivered into small splinters about two inches long. A
portion of the stream appears to have been conducted by the
gutter communicating with the metallic spout of No. 22 to
that betweeen Nos. 20 and 21, down which it proceeded,
thrusting the lower wooden spout about three or four inches
from the wall, and chipping away portions of the brickwork
in its passage through the front wall of No. 21, which it per-
forated (the aperture being of a considerable size), and imme-
diately passed to the principal wheel of a silk-winding ma-
chine. A woman who was attending the machine, and had in
her hand at the moment a spindle, received a severe shock,
and was hurled by the force across the room. This stream
appears to have given off' a lateral stroke, which manifested
its effects at the box of the lock of the street door, tearing away
the plastering and paper as it passed into the front room, in

* The western wall of this house has been so shaken by the stroke that
it is considered necessary that it should be taken down and rebuilt.

M2

164 Mr. W. R. Birt oji the Production of Lightnmg by Rain.

which a pane of glass was shattered. A woman who was near
this room at the time described the passage as being filled
with a light of a blue colour, and saw the lightning pass out of
the back window over her child's head. It would appear that
at the time the lightning was passing from one metallic con-
ductor to another in the immediate front of the houses, a
young man named Thomas Johnson opened the street-door
of No. 17: he was accompanied by a lad of about fourteen
years of age, who was, almost immediately after the door was
opened, thrown backwards. The shock was so sudden that
he knew not what happened to Johnson, who was found
shortly after lying on his side, his back to the wall, and feet
just beyond the threshold of the door, quite dead. He was
evidently struck by the lightning, which, playing in the front
of the houses, was probably attracted by the metallic spout
that terminated a few feet above the door. The plaster just
above the door, and which was most probably over his head,
was torn away; but there is no mark or perforation to trace
its entrance from above ; the probability appears to be, that a
stream struck upwards immediately after striking him. The
two houses immediately opposite to Nos. 21 and 22 also re-
ceived some injury from the lightning glancing sideways, as it
were, from the principal stream which sliattered the roof of
No. 22.

It cannot fail to be remarked, that the principal mischief
after No. 22 was struck occurred in the front, and more or
less in the neighbourhood of the metallic spouts, which
answered the purpose of imperfect conductors, the metallic
continuity being interrupted on the roofs by the leaden gutters
extending only a certain distance on each side of the metallic
spouts, and also in front of the houses by the wooden spouts
carrying the water to the earth. In connexion with the pre-
sence of the lightning in the front, the altitude of the houses
struck renders it rather improbable that the stroke descended
immediately from the cloud. The houses in West Street are
the lowest in the neighbourhood; those in the street immedi-
ately to the north are rather higher; and at the further end of
the street, near No. 1, are three houses in North Street consi-
derably higher; so that had the stroke descended immediately
from the cloud above, which it is to be presumed was at the
usual elevation of clouds under these circumstances, the pro-
bability is that the high houses in North Street would have
been struck rather than the low houses at the further end of
West Street. Should it have been the case that the stroke
emanated from an altitude but little above the houses struck,
we nave evidently to seek the cause of the discharge below the

ProK De Morgan on Anharmonic Ratio. 165

cloud. It is extremely difficult to connect the stroke with the
discharge at 2^ 5"* P.M. ; although the concurrent testimony
of the witnesses would lead to the high probability that such
was the case, especially as one stated that it occurred some
considerable time previous to the hail that fell. The general
impression in the neighbourhood appears to have been, that
the lightning shot or glanced over the houses to the north of
West Street, when it struck the corner, and did not descend
perpendicularly from a considerable height. The discharge
at 2'* 5™ P.M. was, as we have already observed, precededby a
gush of heavy rain ; and taking the suggestion in the report
alluded to above into consideration, there appears to be great
probability that the formation of the lightning was in accord-
ance therewith. For upwards of half an hour violent me-
teorological action had taken place, the precipitation of rain
being very prominent. There can be no question that this
precipitation was accompanied by well-marked electrical phae-
nomena ; and when, as at 2^ 5™ p.m., an increased but sudden
precipitation occurred, it is likely that an agglomeration of
the smaller drops took place, increasing, as suggested, the
electric tension to such an enormous extent, that a flash
escaped /« the immediate neighbourhood of the houses struck; and
when we consider that at the time several millions of drops
must have been falling, each contributing its quota to the
general result, it is not to be wondered at that the tension of
the electricity was so great as to produce the very violent
effects witnessed.

Bethnal Green, August 4, 1849.

G

XXIII. On Anharmo7iic Ratio, i^/ Professor De Morgan*.

EOMETRICAL communications to scientific journals
are not so common as they used to be, which may partly
be attributed to the expense of woodcuts, and partly to the
decline of taste for geometry. The latter is accelerated by the
paucity of geometrical reading arising from the former cause:
and its effect upon soundness of mathematical habits is deadly.
But there is no reason why the expense of woodcuts should
place any obstacle in the way. I am satisfied, from sufficient
trial, that when proper description of the diagram is given in
the text, the person who draws his own diagram from the text
will arrive at the author's meaning in half the time which is
employed by another, to whom the successive appearance of
the parts is prevented by his seeing the whole from the be-

* Communicated by the Author.

166 Prof. De Morgan on Anharmonic Ratio.

ginning. Tlie great work of M. Chasles has not a single
diagram.

It will be asked whether the omission of diagrams will not
cause a misprint (such as must sometimes occur) to be fatal to
the reader's chance of arriving at the result. Putting out of
view the very great confusion which a misprint causes when
it shows a variance with the diagram, and leaves the reader
unable to decide which is wrong, I will remark that it is pos-
sible very greatly to diminish the risk of error in the descrip-
tion of the diagram. This is all that is wanted: for grant the
reader once able to establish the diagram, and his position is
then as good as (at least, I say better than) that of the person
who has had the use of a woodcut. My plan would be to
double every letter thejirst time it occurs. Instead of ' Let AB
be a given straight line, and C a point without it,' I should
write ' Let AABJB be a given straight line, and CC a point
without it.' This would present, I think, a twofold advantage.
First, neither author nor compositor is so likely to put in DD
instead of BB as D instead of B, Secondly, in looking back
to recover the meaning of a letter, the eye would be caught
by the I'eduplication which marks its first appearance, whereas
at present search is often necessary. I need not state that the
omission of the diagram would compel writers to be complete :
at present they sometimes (but always implying profession
of the contrary) rely upon it that the reader will supply omis-
sions by the diagram.

I propose in this present paper (which, however, will con-
tain nothing elaborate enough to require any use of the pre-
ceding suggestion) to state the mode in which the theories of
transversals^ of the anharmonic ratio^ and of the complete qua-
drilateral^ in their simplest parts, may be "connected together,
by the help of a theorem which I believe to be new. I shall
hardly state more than results. I use the geometrical lan-
guage of composition of ratios, and symbols representative of
it. It must also be noticed that no demonstration need in-
volve any part of the sixth book except the first proposition.

(1.) Let A : B represent the ratio of A to B, and (A : B)
(C : D) the ratio compounded of the ratios of A to B and C
to D. The symbol 1 : 1 may be used for a ratio of equality.
(2.) When a point is stated to be on a line, let it be under-
stood that it may be on the line produced ; and when two lines
are stated as meeting, the point of intersection may be in either
or both produced. (3.) Two lines are said to be internal
segments of their sum, external segments of their difference:
so that AC, CB are always segments of AB, when A, B, C
are in one line. (4.) When there are four points, P,Q, R, S,

Prof. De Morgan on Anharmonic Ratio. 167

in one line, in any order, let (PQRS) denote the ratio com-
pounded of PQ: QR and RS: SP, or (PQ: QR)(RS: SP).
This is what M. Chasles has styled the anharmonic ration by
an extension of its well-known case in which (PQRS) is 1 : 1,
in which case PR is said to be harmonically* divided in Q
and S. Since the letters P, Q, R, S can be written in twenty-
four different orders, there are as many forms in which an
anharmonic ratio may be presented. But all these forms are
only three ratios and their inverses : nor are these three di-
stinct, for they are always of the connected forms A : B,
A : A + B, B : A + B. And the rules for separation and col-
lection are as follows.

To find the distinct anharmonic ratios. Take any one, say
(QSRP), advance the first letter one interval, and two inter-
vals, giving (SQRP), (SRQP): theee three are distinct; and
if the first be A : B, the second is A: C, the third is B : C, and
of A, B, C, some one is equal to the sum of the other two.

To Jind forms of equivalent ratio. Invert all the letters, or
pairs, or one after the other ; thus(RSPQ), (QPSR), (PQRS),
(SRQP), are the same.

To find the forms iiohich have ratios inverse to that in any
given form. Change either extreme into the other, or inter-
change the first and third, or second and fourth: thus if
(SQRP) = A:B, either of these four (QRPS), (PSQR),
(RQSP), (SPRQ), isB:A.

To express the ratios circuitously^ or in the order A:B, B:C,
C : A. Make two transferences of the first letter and of the
second: thus if (PQRS) be A:B, (QRPS) is B : C, and
(PRSQ) is C:A.

Tofnd convenient values of A, B, C. Look for the order
in which the letters occur on the line, say P, Q, R, S. Take
the rectangle under PQ and RS, with wholly unconnected
sides; under PS and QR, one of which contains the other;
and under PR and QS, in which each side is partly in and
partly out of the other. Call these A, B, C ; then C = A + B,
and (PQRS) = A : B. Call this, and its inverse, the primary
ratio.

(5.) If two systems be anharmonically equivalent, the six
ratios (counting inverses) of one being severally equal to those
of the other, then the primary ratios are equal, each to each.

(6.) To what is usually said on harmonic division, I should
add the following. If C, D, and C, D' be conjugate pairs of
points to AB, it is known that of the two lines CD, CD', the

* This mode of speaking is not exactly consistent with the derivation of
the phrase ; it is PR which is an harmonic mean between PQ and QS, ac-
cording to the received use of the word harmonic.

168 Prof. De Morgan on Anharmonic Ratio.

less is entirely within, or entirely without, the greater. Hence,
Pbeingany point, CPDand C'PD' cannot both be right angles;
from which, by a very easy reductio ad absurdum, it follows
that if CPD be a right angle, PC bisects the angle APB. For
an easy* mode of finding any number of pairs of conjugates,
with a given line AB, proceed as follows. Take BAP iso-
sceles at A, and bisect BP in Q. Having a point C in AB,
take in AP AC'= AC, and draw C'Q meeting AB in D : then
C and D are conjugate.

(7.) If two triangles, ABC, A'B'C, have their bases, AB
A'B', in the same line, which cuts CC in Z, the areas are in
the ratio compounded of the bases AB, A'B', and the segments
of the line joining the vertices, CZ, C'Z. Join BC : then
CAB: C'A'B' is (CAB: CZB)(CZB : ZBC')(ZBC': C'A'B'),
or (AB:ZB)(ZC:ZC')(ZB:A'B'), or (AB : AB')(CZ: C'Z).
If the bases be equal, the areas are as CZ:C'Z. Hence
the fundamental proposition on transversals is most easily
proved. If the sides of ABC be cut by a line cutting BC in
A', CA in B', AB in C, then the number of external sectious
is odd, and (AC: C'B)(BA': A'C)(CB': B'A)=1 : 1. Join
A A', CC by vi. 1, and (7 ) : the compound just mentioned is
(AA'C : BA'C) (BA'C : CA'C) (CA'C : AA'C) or 1:1.
Many writers prove the converse incorrectly, both in this pro-
position and others. If there be A' B' Con the three sides,
with an odd number external, and (AC: CB)(BA': A'C)
(CB': B'A)=1 : 1, then A', B', C are in one line. If not,
let A'B' meet AB in C" : then C" may be written for Cin the
hypothesis, whence AC : C'B : : AC" : C" B, and either C and
C" coincide, or they are conjugate points in AB. In the last
alternative C" is internal or external, according as C is ex-
ternal or internal : but A', B', C have by hypothesis, an odd
number of externals, therefore A', B', C" (in a straight line)
have an even number or none, which is absurd.

(8.) If O be any point, and OA, OB, OC, cut BC, CA, AB
in A', B', C, then an odd number of sides is cut interrially,
(AC':C'B)fBA': A'C)(CB' : B'A) = 1 : 1. This compound,
by (7.), is (AOC : COB) (BOA : AOC)(COB : BOA), or 1 : I.
Treat the converse as before.

(9.) Let A'B'C be a triangle having its vertices on the
sides BC, CA, AB of the triangle ABC, and let A'B', B'C,
CA' cut AB, BC, CA, in C", B", A"; so that BC is cut in
A' and A", &c. Then the division is internal and external in
all, or in none. Let A'B'C be called an inscript of ABC,
and ABC a descript of A'B'C.

* Even in drawing without ruler and compasses, this method will be
found a useful assistant to the eye.

Prof. De Morgan on Anharmonic Ratio. 169

(10.) The three sides, AB_, BC, CA, are anharmonically*
divided in the same manner, giving (AC'BC")='(BA'CA")
= (CB'AB"). The transversals passing through A' show that
CA': A'B is both (CB" : B"A)(AC' : C'B) and (CB': B'A)
(AC": C"B). A very easy form of the proof is this : each
of the ratios (AC'BC") &c. is nothing but the compound
(AC : C'B)(BA': A'C)(CB' : B'A). Converses may be made.
(11.) If two lines meeting in Z, be cut by three lines meeting
in O, in A, B, C, A', B', C', then they have similar anharmonic
divisions, and (ZABC) = (ZA'B'C'). Draw AB', A'B, &c.
and there are six cases of inscription ; A'BO and AB'O are
inscripts of ZCC; B'CO and BCD of ZAA'; C'AO and
AC'Oof ZBB': from which the theorem follows instantly,
and, of course, its extension to any pencil of four lines and
any pair of transversals. The particular case, where the an-
harmonic ratios become those of equality, must of course be
noted. Also, that if two similar anharmonic systems have one
point in common, the lines joining the points of the three cor-
responding couples meet in one point. (12.) Notice that
A"B"C" is an inscript both of ABC and A'B'C; and call it
the common inscript; or, when A"B"C" are in one straight
line, an evanescent inscript. (13.) When the inscript is har-
monic, that is when the sides of ABC are harmonically divided
by those of A'B'C, then AA', BB', CC meet in one point:
and the converse. (14-.) When the inscript is harmonic, the
common inscript is evanescent ; and the converse.

(15.) The complete quadrilateral is a triangle and a trans-
versal, in four different ways. If, as before, ABC be the tri-
angle, and A'B'C the transversal, then A, A' are opposite
points, as are B, B', and C, C. The /r/nfrf of quadrilaterals is
ABA'B', BCB'C, CAC'A'. Draw the diagonals A A', BB',
CC, and let AA', BB' meet in C" ; BB', CC, in A"; CC,
A A', in B". In the figure are seven lines, and ABA'B' and
its attendants are complete. But there are six other sy-
stems of quadrilaterals, each of which is incomplete, wanting
one diagonal, and dispensing with one of the seven lines.
Thus AA'BB' has the diagonals AB, A'B', wants CC", and
has nothing to do with CC. Throw out the line CC, replace

* I take this theorem to be new, which I should not have done from its
being new to me when 1 found it: but on communicating it to Mr. T. S.
Davies, whose research in this subject is far above mine, I found that it was
equally new to him. But I shall not definitively call it new till I hear what
M. Chasles says on the subject. I may add, that the substitution of (10.)
for the celebrated proposition of Pappus in (11.) is the joint work of Mr.
Davies and myself. On my communicating (10.), he returned me a de-
monstration of it by means of (11.), from which I saw that (11.) was really
a case of (10.)

AA'B'B

AB', A'B .,

.. C'C"

BB'C'C

BC, B'C .

.. A'A"

CC'A'A

CA',C'A ..

. B'B"

170 Prof. De Morgan on Anharmonic Hatio,

it by CC", and AA'BB' is complete, while ABA'B', which
was complete, takes its place among the incomplete ones. As
follows :

AA'BB' has diagonals AB, A'B' wants CC" and dispenses with CC.
BB'CC ... BC, B'C ... A A" ... A A'

CC'AA' ... CA, CA' ... BB" ... BB'

CC

AA'
BB'.

(16.) That each diagonal is harmonically divided by the
other two is well-known ; but this is only a very small part of
the following. Take any two points and their opposites, say
A, C, A', C. Any triangle made from three of these, say
ACC, has BB'B" for an harmonic inscript, as proved by the
lines which meet in the fourth point, A'. This gives twelve
cases of harmonic inscription. (17.) Let A"B"C" be called
the diagonal triangle', it has four harmonic inscripts. Of the
remaining six letters take any three which are in the same
straight line, say A'BC. The other three AB'C, show an
harmonic inscript of the diagonal triangle, A'BC, first named,
being the evanescent common inscript.

(18.) Hence it follows that A"A, B"B, C"C, &c. meet in
one point. Let them meet in 0 ; A"A, B"B', C'C, in 1 ;
A" A', B"B, O'O, in 2; A"A', B"B', C'C in 3. There are
then six new lines 01, 12, 23, 30, 02, 31. If C'A" be taken
as a seventh line, then 0123 is complete ; if B"C", then 1203 ;
if A"B", then 2013.

The above will be sufficient for my purpose, and will show,
I think, the value of the anharmonic ratio. It will be observed
that I adhere closely to the language of geometry, and do not
admit that of algebra: but I go further, and, while thinking
of the subject, do not admit the Jiotions of arithmetic. From
various writers I gather that they think, in compounding the
ratio, say of AB to CD and PQ to RS, there is no choice
except either to compare the rectangles under AB and PQ
and under CD and RS, or else the products AB x Pd and
CD X RS, the linear symbols being interpreted numerically:
so that the composition of three linear ratios in plane geometry
is resisted as involving the use of solids. But if any one will
accustom himself to fix his mind upon alteration i?i a ratio as
an operation which can be conceived independently of number,
and executed independently of rectangles, he will find that the
propositions of the geometry of transversals, &c. have a vitality
which the algebraic forms cannot give them. The following
process would not only help the confirmed algebraist to receive

On the Inorganic Constituents of Organic Bodies. 171

the notion for which I contend, but would be a useful exercise
in drawing. P'orni a triangle ABC, and a transversal A'B'C,
draw any line K, and make an attempt by unassisted estima-
tion to alter K into L in the ratio of AC : C'B : and then
cover K over with a bit of paper. By estimation again, draw M
so that L : M as BA' : A'C, and N so that M : N as CB' : B' A.
Then N and K should be equal. In all this there is neither
occasion to think of a solid, nor of an area, nor of a numerical
product.

XXIV. On the Inorganic Cofistituents of Organic Bodies. By
H. Rose, Professor of Chemistry in theUniversity of Berlin *.
[Continued from p. 24.]

[The following are the Appendices referred to in the prece-
ding portion of Prof. Rose's paper, at p. 4 et seq. of the present
volume. They have been slightly, but not materially, abridged,
and principally only in regard to the details of such analytical
methods of examination as have yielded unfavourable results
in the hands of the author, or such facts as have been described
in the preceding part.] _

Appendix I. and II.

Examination of the Inorganic 'Constituents of Peas arid Pea-
straw. By M. Weber.

300 grms. of peas and 100 grms. of pea-straw were used.
After carbonization the mass was treated according to the
method previously described.

The aqueous extract, when evaporated to dryness, fur-
nished in the case of the peas, ri^O grm.; in the case of the
pea-straw, 1*417 grm.

These residues gave the following results per cent. —

Peas,

Pea-straw

Chloride of potassium

47-54

7-14

Chloride of sodium .

8-16

6-65

Potash

30-26

57-10

Lime

. ...

0-70

Phosphoric acid . .

4-47

...

Sulphuric acid . .

. 0-79

2-12

Carbonic acid . . .

8-33

23-12

Silica

...

1-48

99-55 98-31

These constituents, when calculated as salts, yield the fol-
lowing composition : —

* From PoggendorfF's Annalen, Ixxvi. p. 338.

1 72 Prof. H. Rose on the Inorganic Constituents

Peas.

Pea- straw

KCl . . .

4-7-54

KCI . .

. 7-14

NaCl . . .

8-16

NaCl .

. 6-65

3KO+PA

13-32

KO, SO3

. 2-46

KO, SO3 . .

1-72

KO, CO2

. 72-62

KO, CO, .

26-16

KO, SiOg

. 4-49

KO, HO .

3-13

KO, HO

. 3-88

100-03

CaO, SO3

. 1-69

i 98-93

Thus the chlorides exist in the aqueous extract of the car-
bonized peas in far larjrer quantity than in that of the pea-
straw. Phosphoric acid exists only in the peas; it is entirely
absent from the aqueous extract of the carbonized pea-straw ;
whilst the latter contains a much larger quantity of carbonate
of potash than the carbonized peas, so that the evaporated
aqueous extract of the carbonized pea-straw would have exactly
the same composition as several of the commercial kinds of
potash.

The aqueous extract of both the carbonized peas and the
pea-straw contained some, although not a large quantity, of
free potash, formed by the above-mentioned action of the car-
bon upon carbonate of potash. As we have already stated,
the conversion of the potash into the carbonate by the trans-
mission of carbonic acid through the solution was omitted in
all the analyses. Hence it is calculated as potash in the eva-
porated aqueous extract.

Muriatic extract. — The carbonized peas after exhaustion
with water did not evolve carbonic acid when treated with
muriatic acid ; the carbonized straw, however, effervesced
strongly, and hence contained a large quantity of earthy car-
bonates. As the amount of carbonic acid could not be deter-
mined directly, the lime and magnesia not precipitated from
the muriatic solution by ammonia in the form of earthy phos-
phates are calculated as carbonates.

The composition of the constituents in the two extracts was

as follows : —

Peas. Pea-straw.

Potash 54-63

Soda 7-56

Carbonate of lime 60*19

Carbonate of magnesia . ... 5*26

Lime 8-22 6-92

Magnesia 6*52 5-69

Peroxide of iron . . . 1*33 I'lS

Phosphoric acid . . . 20-79 18-29

Silica 0-95 2-52

100-00 100-00

of Organic Bodies. 1 73

The large amount of potash in the acid extract of the car-
bonized peas is very remarkable. The quantity of phosphoric
acid present is about sufficient to form with the lime and mag-
nesia 2CaO, PgOg, and 2MgO, P2O5; the calculated quantity
of phosphoric acid would then amount to 21*92 per cent.
Were it even admitted that the alkalies had formed with the
two earthy phosphates, compounds of c-phosphoric acid inso-
luble in water, the quantity of alkali would be far too great
for this purpose; for the potash alone requires more phos-
phoric acid than was found to form 3K0, P2O5.

The amount of phosphoric acid found in the acid extract of
the carbonized pea-straw is exactly sufficient to form 6-phos-
phates with the lime and magnesia ; the calculated per-centage
of phosphoric acid would then amount to 18'53. But both
the salts undoubtedly exist in the carbonized residue in the
form of c-phosphates, and the amount of the carbonates of lime
and magnesia must be less by so much as is requisite to form
c-phosphoric acid from the 6-phosphates.

Remaining carbonaceous mass. — The following is the com-
position per cent, of the ash obtained b}' incinerating the ex-
hausted carbonaceous mass of the peas and pea-straw.

Peas. Pea-straw.

Potash 24-14

Lime 5*25 1-87

Magnesia .... 11*22 14< 66

Peroxide of iron . . 0-85 7"73

Phosphoric acid . . 58*03 20*80

Silica 0*51 54*94

100*00 10000

Considering the large quantity of phosphoric acid in the
ash of the peas, we must admit that one portion of the bases
is combined with rt-phosphoric acid, and another with Z'-phos-
phoric acid. If we calculate the lime and magnesia, as also
the small quantity of peroxide of iron as 6-phosphates (which
certainly ought not to be done in the case of the peroxide of
iron), 26"08 per cent, of phosphoric acid are required. If we
assume that the remaining 31*95 per cent, of phosphoric acid
are combined with the potash to form KO, Pg O5, we require
21-09 per cent, of potash. The quantity found is 305 per
cent, more than this.

For the purpose of showing the important difference which
occurs when the incineration of the exhausted carbonized mass
is eillected by the aid of a solution of platinum, or by my
former method, by combustion in oxygen, the result of the
examination of the ash of this substance may be brought for-

174« Prof, H. Rose on the Inorganic Constituents

ward here, as obtained by the latter defective method. In
this case it amounted to r424< grm. from 300 grms. of peas,
whilst by the other method 2*726 grms. were obtained.
It consisted per cent, of —

Potash 17-83

Lime 8*77

Magnesia .... 20-85

Peroxide of iron . . 2-24<

Phosphoric acid . . 46'98

Silica 1-89

98-56

The amount of the potash and phosphoric acid is diminished
by the volatilization of the phosphate of potash ; whilst that of
the lime, the magnesia, the peroxide of iron, and the silica
have been increased.

The proportion of the phosphoric acid to the bases in the
ash of the pea-straw is the same as that in the 6-phosphates.
Yet only lime and magnesia could have been combined with
the ^'phosphoric acid, since the quantity of this acid found is
only sufficient for these bases. If the two earths were con-
sidered as Z»-phosphates, 21-60 per cent, phosphoric acid
would be required. The considerable quantity of peroxide
of iron must not be considered as existing in combination with
phosphoric acid in the ash.

The following are the inorganic constituents contained in
the muriatic extract and the incinerated carbonized residue
of peas ; they have been added together, because they are
sometimes considered as constituting the portions of the ash
insoluble in water.

Potash 32-66

Soda 2-11

Lime 6-08

Magnesia .... 9*91

Peroxide of iron . . 0*98

Phosphoric acid . . 4'7'62

Silica 0-64

100-00

We thus see the large amount of alkali contained in those
constituents which are insoluble in water, and the presence of
which has previously been almost always overlooked.

The inorn-anic constituents of the muriatic extract and in-
cinerated carbonized mass of pea-straw were —

of Organic Bodies.

175

Carbonate of lime
Carbonate of magnesia
Lime . . .

Magnesia . .
Peroxide of iron
Phospiioric acid
Silica . . .

54-29
4-77
6*42
6-58
1-78

18-52
7-64

100-00

The following is the result of the analysis of the inorganic
constituents of peas : —

In the aqueous extract of the carbonized peas 23*61 per cent.

In the muriatic extract 21-48 ...

In the ash of the carbonized mass . . . 55-36 ...

100-45

The total amount of inorganic constituents of the peas was
1-64 per cent.

Hence the constituents obtained in the three operations
were —

Chloride of potass
Chloride of sodiun
Potash . . .
Soda ....
Lime ....
Magnesia
Peroxide of iron
Phosphoric acid
Sulphuric acid .
Carbonic acid .
Silica ....

urn

Oxygen.

11-02

1-89

82-15

5-44-j

1-62

0-41

4-67

1-31 Uo-33

7-62

2-94

0-76

0-23J

37-67

21-10^

0-18

0-10

>22-84

1-94

1-39

0-48

O-25J

100-00
The pea-straw yielded —

Extracted by water from the carbonized mass 27*00 per cent.

Extracted by muriatic acid 65-87 ...

Ash of the residuary carbonized mass . . 7*13 ...

100*00

The total amount of inorganic constituents of the pea-straw
amounted to 5-25 per cent.

The constituents obtained in the three divisions of the ana-
lysis yielded —

176 Prof. H, Rose on the Inorganic Constituents

Oxygen.
Chloride of potassium . 1*96
Chloride of sodium . . 1'83

Potash 15-68

Lime 27-14.

Magnesia 6-50

Peroxide of iron . . . 1*30

Phosphoric acid . . . 13-52

Sulphuric acid . . . 0-57 0-34. I

Carbonic acid . . . 25*52 18-46 f

Silica 5-98

13*18

26*37

100-00

The proportion of the oxygen of the bases to that of the
acids in both the peas and the pea-straw is therefore as 1 : 2.
The oxygen of the silica in the pea-straw is not added to that
of the other acids, because it is not combined with bases in the
straw.

The manner in which the inorganic constituents of organic
substances are usually determined, consists in the direct in-
cineration of the organic substance, and in arranging the
constituents found in the analysis, by uniting the strongest
bases with the strongest acids. The carbonic acid in many
cases was not determined directly ; and the portion of the
bases remaining, after calculating the salts formed by them
with the acids found, was assumed as carbonates. The above
results show to what very erroneous ideas this method of ar-
rangement may lead. On calculating according to the above
principle the salts from the numbers quoted last, we should
obtain totally different arrangements, or at least totally differ-
ent per-centage results from those obtained by the separate
exhaustions of the carbonized substance. Thus all the alkali,
for instance, in the ash of the peas remaining after calculating
the amounts of chloride and alkaline sulphate, would be re-
garded as alkaline phosphate. The phosphoric acid then
remaining would be combined with other bases, and what
remained of the latter would be regarded as combined with
carbonic acid. But we have now seen that part of the potash
exists in the aqueous solution of the carbonized mass in the
state of carbonate, and that in the teleoxidic portion of the
carbonized mass the earths extracted by the muriatic acid
could only have been combined with phosphoric acid, because
no carbonic acid is evolved when an acid is added.

This principle is seen to be still more erroneous in the de-
termination of the inorganic constituents of the pea-straw.
No phosphoric acid exists in the aqueous extract of the car-

of Organic Bodies. 177

bonized mass, but almost all the potash is combined with car-
bonic acid, whilst the earths in the teleoxidic portion of the
carbonized mass are mostly combined with carbonic acid, and
partly with phosphoric acid.

The fact that organic substances, the ash of which consists
principally of earths, may be very easily incinerated, whilst
those which contain a large amount of alkalies are very diffi-
cultly so, forms an important objection to the complete inci-
neration of the organic substance for the determination of the
amount of ash contained in it. For by the prolonged heat
required in the latter case, the greater portion, and frequently
the whole of the alkaline chlorides, especially the chloride of
potassium, is volatilized ; or by the action of Z'-phosphates
with the aid of water, or by the hydrogen evolved and the
oxygen of the air, muriatic acid is liberated, and they are
thus converted into c-phosphates. Carbonic acid is driven off
in the same manner. For this reason, in the incineration of
those organic substances which abound in alkalies, Wacken-
roder has proposed to mix them with a weighed quantity of an
earth, to prevent their fusion and to promote the ready com-
bustion of the carbon.

Appendix III. and IV.

Examination of the Inorganic Constituents of Rape-seed and
Rape-straw. By M. Weber.

Aqueous extract, — The following are the per-centage re-
sults : —

Chloride of potassium .
Chloride of sodium

Potash

Lime

Phosphoric acid .. .
Sulphuric acid . .
Carbonic acid . . .
Silica

Rape-seed,

Straw.

1-39

3-82

• ••

9-71

67-88

58-91

• ••

0-32

12-84

2-08

1-86

11-11

25-32

1-21

1-4.7

96-51 100-41

On calculating the salts from the constituents obtained, a
very large amount of free potash remains in excess, which
existed in the evaporated residue as hydrate of potash. The
apparently considerable loss arises from the water of the hy-
drate of potash not having been given among the constituents.
Moreover, on account of the large amount of fatty oil in the
seeds, a very large quantity of olefiant gas was evolved during

Phil. Mag. S. 3. Vol. 35. No. 235. Sept. 1849. N

178 Prof. H. Rose on the Inorganic Constituents

the carbonization, and this caused the conversion of so large
an amount of carbonate of potash into potash.

The above constituents, when calculated as salts, yield the
following composition :-

Rape-seed.

Chloride of potassium . . . .

1-32

Tribasic phosphate of potash . .

38-19

Sulphate of potash ....

. 4-51

Carbonate of potash ....

34-89

Tribasic silicate of potash . . .

4*86

Hydrate of potash

15-10

98-87

On calculating the hydrate of potash as the carbonate, the
composition of the aqueous extract would be —

Chloride of potassium .... 1*35

Potash 66-28

Phosphoric acid 12 "54

Sulphuric acid 2*03

Carbonic acid 16*61

Silica 1-19

or

Chloride of potassium . . .
Tribasic phosphate of potash .
Sulphate of potash ....
Carbonate of potash ....
Tribasic silicate of potash . .

100-00

. 1-35

. 37-29

4*4 1

. 52-20

. 4-75

100-00

The aqueous extract of the carbonized straw did not con-
tain any free potash. The constituents of the extract, when
calculated as salts, give the following composition : —

Chloride of potassium .... 3-82

Chloride of sodium 9-71

Sulphate of potash 3*06

Carbonate of potash 79'53

Tribasic silicate of potash . . . 4*46

Sulphate of lime 0'77

101-35

Muriatic extract. — The carbonized seeds, after exhaustion
with water, did not effervesce on the addition of muriatic acid;
the straw, however, did so copiously.

of Organic Bodies. 179

The composition in 100 parts was as follows: —

Seed. Straw.

Potash 30-45

Soda 4-48

Carbonate of lime 63*38

Carbonate of magnesia . ... 20*46

Lime 8*06 4*45

Magnesia 14*34 046

Peroxide of iron . . 1*36 2*13

Phosphoric acid . . . 40*63 5*93
Sulphuric acid . . . 0*32

Silica 0*36 3-19

100*00 100*00
The composition of the phosphates precipitated by am-
monia from the muriatic solution was as follows, after havmg
been heated to redness :— 8CaO + Pg O5+ 2MgO + P2 O5
+ 2Fe2 03 + 3P2 O5. The calculated quantity of phosphoric
acid in this precipitate amounts to 34*24 per cent. ; analysis
yielded 34*47 per cent. Thus there is an excess of 6*16 per
cent, phosphoric acid.

The phosphates precipitated by ammonia from the acid
extract of the straw consisted, after having been heated to
redness, of 2CaO, Pg O5 + 2MgO, P2 O5 + Fcg O3.

T^e remaining carbonaceous mass. — The ash it contained
consisted of —

Seed. Straw.

Potash 21-50

Soda 0*29

Lime 15*19 27*53

Magnesia 14*08 13*51

Peroxide of iron . . . 0*46 4*20

Phosphoric acid . . . 45*79 9*29

Sulphuric acid . . . 1*87
Silica 0*82 45*47

100-00 100*00
The composition of the phosphates precipitated by am-
monia from the acid solution of the ash of the seeds was
2CaO, P2O5 + 2MgO, P2O5+ Fe203, 3P2 O5. The phosphoric
acid required by calculation is 44*17 per cent.; that found by
experiment amounted to 44-10 per cent. Hence there is an
excess of 1-69 per cent, phosphoric acid, which existed in the
liquid filtered from the earthy phosphates. Ammonia how-
ever produced only a very slight precipitate in the acid solu-
tion of the ash of the carbonized straw ; the fluid filtered from
this still contained lime and magnesia.

N2

180 Prof^ H. Rose on the Inorganic Constituents

The following results were obtained in the three divisions
of the examination of the inorganic constituents of the rape-
seed and rape-straw: —

Seed. Straw.

Extracted by water from the car-1 ^.^^ ^^ g^.^^ ^

bonized mass J '^ *^

Extracted by muriatic acid . . . 35*60 p. c. 4«5*91 p. c.
In the ash of the residue . . . 54-'90 p. c. l^'SO p. c.

100-00 p. c. 100-00 p. c.

The inorganic constituents of the rape-seed amounted to
2*48 per cent., those of the straw to 3-93 per cent.

Hence the following are the whole of the inorganic consti-
tuents of the rape-seed : —

Chloride of potassium . . 0-13

Potash 28-94

Soda

Lime

Magnesia

Peroxide of iron ....
Phosphoric acid ....

Sulphuric acid

Carbonic acid

Silica

Oxygen.

4-90 I
0-44 l^
2' 3 3
4-97
0-22 J
22-851
0-80
1-14
0-36

12-86

y 25-15

100-00

The amount of oxygen in the acids is twice as great as that
of the bases in the rape-seed as in peas.

The rape-straw yielded the following inorganic consti-
tuents : —

Chloride of potassium
Chloride of sodium
Potash . . .
Lime ....
Magnesia . .
Peroxide of iron
Phosphoric acid
Sulphuric acid .
Carbonic acid .
Silica ....

Oxygen.

1-48

3-79

23-02

3-90

22-47

6-31

6-72

2-60

1-57

0-48

4-07

2-28

0-76

0-45

27-51

19-90

8-61

4-47

13-29

27-10

10000

Two analyses were also made of rape according to the old
plan, and were found to yield the same errors as those which
have been previously described.

of Organic Bodies. 181

On comparing the constituents of the ash of peas with those
of rape-seed, we find that the aqueous extract of the car-
bonized peas differs essentially from that of the carbonized rape
in the large amount of alkaline chlorides which it contains,
and which are present in very small quantity in the rape,
whilst the latter contains more phosphate of potash than the
former. The muriatic extract of the carbonized rape also
contains much more phosphoric acid than that of the peas,
whilst the anoxidic portion of the carbonized mass of the peas
yields more phosphoric acid than that of the rape. The in-
organic constituents of the pea- and the rape-straw are how-
ever very similar to each other.

Appendix V.

On the Amount of Silica contained in some Plants.
By M. Struve.

As is well known, the stems of the Equisetace^e when incine-
rated leave a residue consisting of almost pure silica, which
retains the form of the original stem. It fuses before the
blowpipe on charcoal. If this residue be exhausted, first with
water and then with muriatic acid, which dissolve very small
quantities of alkaline salts, among which we find phosphoric
acid, together with sulphate and phosphate of lime, it no
longer fuses before the blowpipe. The ash of the following
species of Equisetum^ after treatment with water and acids,
yielded the following composition : —

Impure

raanganoso-

Silica.

Alumina.

Lime, i

manganic oxide.

Equisetum hiemale

97-52

1-700

0-69

Equisetum limosum

94.-85

0-990

1-57

1-69

Equisetum arvense

95-4-3

2-556

1-64.

The epidermis of the stolones of Calamus Rhodayi, the
Spanish cane, which may be easily separated by repeatedly
bending them, consists almost entirely of silica, whilst the
woody substance itself contains mere traces of it. Muriatic
acid does not remove either alumina or other bases, excepting
a very small quantity of lime. This silica does not fuse before
the blowpipe. After treatment with muriatic acid, it had the
following composition : —

Silica . . . 99-20
Lime . , . 0-45

99-65
Spongia lacustris, from the neighbourhood of Berlin, also

182 Prof. H. Rose on the Inorganic Constituents

leaves an ash having the form of the plant, which, as in the
preceding instances, is not destroyed after exhaustion with
water and muriatic acid, whicli removes some lime. Its com-
position was then as follows : —

Silica . . . 94-66
Alumina . . 1*77
Lime . . . 2*99

99'4.2

It is very probable that the substance stated to be alumina
in these analyses is really phosphate of lime or magnesia.
Alumina has not hitherto been detected with certainty in the
ash of plants.

Appendix VI. and VII.

Examination of the Ash of Wheat and Wheat-straw.
By m. Weber.

The quantity of substance used amounted to SOO grms. in
the case of the grain, and 100 grms. in that of the straw.

Aqueous extract. — During evaporation it deposited copious
films of silica. That of the grain left a residue weighing 1*4 13
grm., that of the straw r216 grm. ; it had the following
composition : —

Chloride of potassium
Chloride of sodium
Potash ....

Soda

Sulphuric acid
Phosphoric acid .
Silica

eat-grain.

Straw.

...

48-09

27*05

2-84

33-64.

2-17

6-37

...

2-34

31-72

...

44-58

98-78 99-92

The presence of so large a quantity of silica in the aqueous
extract of the straw is very remarkable. A soluble compound
of chloride of potassium and silica must be formed under cer-
tain circumstances. The films of silica deposited during eva-
poration, were not changed by digestion with muriatic acid ;
nor did they exhibit any regular structure under the micro-
scope, but consisted of pure silica.

Potash and soda exist in the aqueous extract of the car-
bonized wheat in combination with phosphoric acid in the
form of Z»-phosphates. The amount of phosphoric acid re-
quired by calculation is 32-72 per cent.

of Organic Bodies. 183

Muriatic extract, — The residue consisted of —

Wheat. Wheat-straw.

Potash 14*40

Soda

Lime ....
Magnesia . .
Peroxide of iron
Phosphoric acid
Silica ....

1*66

4'33

46-83

22-35

10-56

1-72

2-96

54-77

33-54

0-77

6-11

100-00 100-00

In the muriatic extract of the wheat, all the bases com-
bined with phosphoric acid are in the form of 5-phosphates.
The quantity of phosphoric acid corresponding to these salts
amounts to 57*20 per cent. ; experiment gave only 54-77 per
cent.

In the muriatic extract of the carbonized straw, the preci-
pitate produced by ammonia consisted of 8CaO + 3P05 + 2Fe2
O3 + 3P2O5; the phosphoric acid thus required amounts to
34*60 per cent. ; analysis yielded 33*54 per cent. The liquid
filtered from this precipitate still contained small quantities of
the carbonates of lime and magnesia.

The exhausted carbonized mass. — The composition of the
ash was as follows : —

Wheat-grain. Straw.

Potash . . .

. . 22*70

Lime ....

. . 7*30

1-97

Magnesia . .

. . 9-86

0-66

Peroxide of iron

. 1-76

1-13

Phosphoric acid ,

. 54*05

1-54

Silica . . .

4-33

94-70

100-00 100*00

On calculating the bases in the ash of the residuary carbo-
naceous mass as i-phosphates, there is an excess of phos-
phoric acid, part of which formed a-phosphates. The bases
would require 44*19 per cent, phosphoric acid to form
Z'-phosphates. The principal constituent of the ash of the
straw was silica. The muriatic solution of the ash yielded
with ammonia a precipitate consisting of 8CaO + 31*2^5 +
2MgO+ P20,:;+ Fcg O3 + P2O5. The liquid filtered from this
precipitate still contained small quantities of lime and mag-
nesia, probably more than would correspond to the solubility
of the earthy phosphates in a solution of muriate of ammonia.

The three divisions of the analysis of the grains and straw
of wheat gave —

IS* Prof. H. Rose oti the Inorganic Constituenis

Grain.

Extracted by water 36*80

Extracted by muriatic acid 43*93

Ash of the remaining carbonaceous mass 19*27

Straw.
31*79
13*39
55*82

100-00 100*00

The inorganic constituents of the grain amount to 1*28 per
cent. ; those of the straw to 3*825 per cent.

Thus the composition of the entire ash of the grain would
be—

Chloride of sodiun
Potash . . .
Soda ....
Lime ....
Magnesia
Peroxide of iron
Phosphoric acid
Silica ....

Oxygen.

10*00

23*18

3*83

3*09

0-76

3*33

0-83

11-75

3*54.

1*11

0*34

46*36

25-97

1*18

^9*30

100*00

The oxygen contained in the bases to that in the phospho-
ric acid is nearly in the proportion of 2 : 5. It has already
been stated that the phosphates obtained in the various parts
of the analysis were pyrophosphates.

The composition of the entire ash of the straw is —

Chloride of potassium
Chloride of sodium
Potash . . .
Lime ....
Magnesia . .
Peroxide of iron
Phosphoric acid
Sulphuric acid
Silica . . .

Oxygen.

15*13

0-89

0*68

0-11

6*93

1-94

1*69

0-65

0-99

0-30

5*05

2-82

0-74

0-44

67*90

•00

-28

100 00

As we have already stated, wheat-straw belongs apparently
to the meroxidic substances. But if we deduct the large
amount of silica, which must be regarded as existing in a per-
fect state of oxidation in the straw, from the anoxidic sub-
stances, so very small a quantity of it remains, that the wheat-
straw may be regarded as an almost teleoxidic substance.

of Organic Bodies. 185

Appendix VIII.

Analysis of the Ash of the Blood of the Ox. By M. Weber.

The entire blood was carbonized by the method stated.

Aqueous extract. — The blood requires to be washed for nearly
fourteen days to obtain a proper extract for the first portion
of the analysis.

The residue of the aqueous extract consisted of —

Chloride of sodium 59-3n rNa CI . . 59-31
14.-67 KO, SO3 . 0-78

11-91 I 3KO, PoO. 1-58

Soda ....
Potash . . .
Phosphoric acid
Sulphuric acid .
Carbonic acid .

or

2'^5

0-53 f"' 1 K0,C02 . 15-31

0-36 I NaO, CO2. 19-67

13-OlJ iNaO, HO . 4.-05

99-79 100-70

The small quantity of free alkali which is produced by the
action of the carbon upon the alkaline carbonate, and which
is considered as hydrate of soda, might perhaps be regarded
more correctly as alkaline carbonate.

Muriatic extract. — This consisted of —

Soda ...... 41-39

Potash 12-60

Lime ...... 6-95

Magnesia 4-10

Peroxide of iron . . . 21-60

Phosphoric acid . . . 13-36

10000

The amount of alkali present is very striking, and is much
too large to allow of the supposition that the alkalies com-
bined with phosphoric acid had existed in the form of double
salts with the earthy phosphates. The quantity of phosphoric
acid found is exactly sufficient to form with the lime SCaO
+ 3PO5, and with the magnesia 2MgO + PO5. The quantity
required by calculation is 13*62 per cent.; that found amounts
to 13-36 per cent. Probably the alkalies existed as chlorides
in the carbonized mass which had been exhausted with water,
and had escaped its action. This is rendered more probable
by the fact, that the sum of the constituents of the muriatic
extract, including the alkalies, amounted to much less than
the direct weight of the evaporated residue.

186 On the Inorganic Constituents of Organic Bodies,

Residuary carbonaceous mass. — It consisted of —

Potash 7-9^

Soda 47-22

Lime 4*09

Magnesia 1*46

Peroxide of iron . . . 16*69

Phosphoric acid . . . 18'37

Sulphuric acid ... 0*61

Silica 3-62

100-00

The amount of phosphoric acid is too small to form c-phos-
phates with the earths and alkalies, much less can the peroxide
of iron be considered as combined with phosphoric acid.

The relative amounts per cent, obtained by the three ope-
rations are —

Extracted by water ....... 60-90

Extracted by muriatic acid .... 6-04

Ash of the residuary carbonaceous mass 33-06

100-00

The whole analysis of the blood gave —

Oxygen.
Chloride of sodium . 36-16

• Soda 27-08 6-92^

Potash 10-66 1-80

Lime ..... 1'77 0-49
Magnesia .... 0*73 0-28
Peroxide of iron . . 6-84 1*09
Phosphoric acid . . 7*21 4-03^
Sulphuric acid . . 0*42 0-25
Carbonic acid . . . 7*94 5-73
Silica ri9 0-61

•10-58

)-10'62

100-00
Hence the statement formerly made, that the inorganic
constituents of the blood agree with those of many seeds,
is only partly correct. The inorganic constituents of the
wheat, excluding a considerable amount of chloride of so-
dium, consist almost entirely of pyrophosphates. The inor-
ganic constituents of peas and rape, which differ in regard
to the amount of alkaline chlorides they contain, nevertheless
agree generally in the amount of the oxygen of all the bases
being about half as great as that of the acids; whilst in the
inorganic constituents of the blood the bases are combined with
much smaller quantities of acids, so that the oxygen of the

The Rev, Brice Bronwin 07i the Theory of the Tides. 187

base is about equal to that of the acids. There is especially
a much less quantity of phosphoric acid to a larger amount
of peroxide of iron in the blood, than in the seeds of the Le-
guminosa^BY the Cerealia. At all events, the blood is a me-
roxidic substance; and the teleoxidic portion of it is only
apparently greater than the anoxidic, because the large quan-
tity of alkaline chlorides in the former cannot be considered
as forming part of the teleoxidic portion.

[To be continued.]

XXV. On the Theory of the Tides.
By the Rev. Brice Bronwin*.

TPHE true principles of fluid motion were not known when
-*- Bernouilli and Euler produced their Theories of the
Tides; and though Laplace in his Theory set out with the
proper equations, he did not succeed in integrating them.
After a very elaborate discussion of the subject, and arguing
in a retardation, he concluded by merely making the height
of the tide proportional to the disturbing forces of the sun and
moon. There are two grand defects in all these theories.
There is no retardation of the water resulting from the mathe-
matical theory itself. If we set aside the contrivances to ac-
count for, or argue in a retardation, they give high water
immediately under the luminary that raises it. And also they
in reality make the direct action of the sun and moon to pro-
duce the whole of the effect; whereas it is admitted that in
narrow seas at least their direct action produces no sensible
effect, which indeed is evident from very obvious considera-
tions.

It is upon the horizontal displacements of the water that
the height of the tide and the retardation chiefly depend. But
these have been neglected ; in fact all the difficulty lies here.
Laplace did not succeed in integrating his equations. The
thing wanted is, to make 8/j, the variation of the pressure, a
complete variation. Until this be done, we cannot expect to
possess a theory which shall harmonize with the phsenomena.
What, therefore, I propose in this and one or two more papers
is, not to give a complete theory of the tides, the phaenomena
of which are in a great measure out of my way, but to attempt
to make Ip a complete variation.

Laplace's theory is contained in the first and fourth books
of the Mecanique Celeste, from which I shall take the neces-

* Communicated by the Author.

188 The Rev. Brice Bronwin on the Them-yofthe Tides,

sary equations, retaining his symbols, which I suppose it will
not be necessary to explain.

From book 4, chap. 1. sect. 4, we have

aW=^Um^v- icos^wVl+ScosSd)

SL

+ -^ sin d cos9 sinucost;cos(w^ + CT— \l/)

SL

+ T-qSin^dcos^jycos 2(w^ + «r— vp). . . . (1.)

This is the part of aV which depends on the action of the
sun or moon. That which depends on the disturbing force
of the water, arising from the deviation of its form from that
of the equilibrium state, is insensible in small seas. And in
these the deviation of the attraction of the land from the regu-
lar law of gravity will mostly be as great, or even greater,
than that of the water ; and its tendency will be in a consi-
derable measure to annihilate the eifects of the latter. We
shall therefore neglect this force.

From book 1 . chap. 8. sect. 36, we have, making the den-
sity unity and restoring p, which the author had made nothing,

+ r28z!r(sin2d ^ +2wsin9cosfl^) = -g8j/-8/?+8V.

In this formula Laplace has very properly neglected the
vertical displacement (s), which is quite insensible in compa-
rison of the horizontal displacements [u) and (u). He has
also left out the terms multiplied by 8;-, which quantity ought
to be considered as of the same order with (s). If in this we
put r= 1, and make

8«,=89( -^ —2n sm Q cos ^ 37 ) +^«^

(sin2d^+2«sinflcosfl^), (2.)

the above becomes

g8y + 8/)=8V-8co.

This, integrated, gives gi/+p=c + Y—oo, where (c) is an arbi-
trary constant. It may, however, contain equations of long
periods in (/), but cannot contain the angle w^ + c7— vj/. Now

The Rev. Brice Bronwin on the Theoty of the Tides. 189

if we make/?=0, this will belong to the exterior surface, and
we shall have

I3/=C+V— CO, (3.)

which gives (t/), the height of the tide.

From the place last referred to we have also

d{r^s) 2 fdu dv u cos ^ \ _ ^

which is the equation of continuity. In this equation the term

dir^s)

-J—- ought to have been left out in consistency with what the

author had done in the other formula. The quantities (m) and
{y) are many hundred, or even some thousand times larger
than {s) ; it cannot therefore be allowable to express this
exceedingly small quantity in terms of them. Leaving it out,
and differentiating relative to (/), there results

. .( d^u d'^v \ .du ^ ,..

sm9( :j7t: + T— 7:)+ cosfi^- =0. . . . (4.)
\dddt d-sfdt/ dt ^

By means of several hypotheses, very wide of the actual
case of nature, Laplace has contrived to integrate this equation,
with all its terms, relative to (r), and to make the terms in the
result all of the same order of magnitude by the introduction
of the depth of the sea into the larger ones as a factor. But
such a result as this cannot be admitted with any tolerable
regard to accuracy.

The condition that Sco may be a complete variation is

d {cPu ^ . . -, dv\ d f . ^ .d^v ^ . . . du\

or

d^u „ . . , d^v d / . „, d%\ ^ . ^ , d^u

. . . d^v d / . „. d^v\ ^ . A .
~2n sm 9 cos fl ^ — y. = -j7\ sm'' 9 -^75 ) +2n sm 0 cos 9-
d'srdi rt9\ dr/

dmdi^ d't^di ~ d$\ dt^/ ' dQdt

which by (4.) may be reduced to

-. — To =-^\sm2 9-7-^)— 2wsm^9-7-. . . . (5.)
d-aidt^ dQ\ dt^J dt ^ '

From (4.) and (5.) we must determine u and v. To abridge,
make (p = w^ + 'B7— vj/. We shall take account of terms depend-
ing on this angle only ; these in their most general form may
be represented by A sin /f + B cos /f. But A and B, being
functions of 6 and /, may be developed in series, the single

190 The Rev. Brice Bronwin on the Tlieory of the Tides.

terms of which will be of the form A'a and B'g, A' and B'
being functions of 5 only, and « and § functions of t only.
Therefore the values of m and v will be sums of terms of the
form

A'« sin /f + B'§cos if = C(a sin /(p + ^ cos /<p)

+ D(« sin /<p — 5 cos if)y
if

C=i(A' + B'), D=1(A'-B').

But the two terms in the second number of this equation may
be put under either of the forms Aa sin i{f — ^, or Aa cos /(<p — §),
which are therefore the most general possible. We may

therefore make u and v^ and also -7-, -r-, equal to the sum of

at at ^

terms of this form ; for the first general assumption applies to
the differential coefficients equally with the quantities them-
selves.
Let then

•^ =sSA«sin /(<p— §), sinfl^ =SB/3cos/((p— g).

These values substituted in (4.) and (5.) will give results of
the form

M sin /(f — g) + N cos i{<^ — g) = 0.

"Whence M=0, N=0, will be equations for determining A
and B.

From (4.) we get

(sin fl -^ + cos dA ja— 2B/3 = 0.

As fl and t are independent of each other, this equation cannot

subsist unless one of them divide out. We must therefore

have

dA.
^=a, sin6 -^ + cosdA = /B. . . . (a.)

And there is no ambiguity ; for whichever of these equations
we assume, it leads to the other.

If we had made /3 = ^a, we should have had /rB everywhere
in the place of B ; therefore making ^B=B', the final result
would not be altered.

Making the same substitution in (5.) which has been made
in (4.), we find, putting

rfvj/ d^

dt dt

—pn

(b.)

The Rev. Brice Bronwin on the Theory of the Tides. 191
ip ^ (sin eB)- (i>-2 sin2fl)A=o"'

{|(si„m)-.'A}|=0 J • •

The first of these has been divided by Uf which multiplied
all the terms. We cannot make in the second

-TT- (sinSB)— 2A=0;

for this would reduce the first to 2sin^fiA=0, which cannot

be. We must therefore have -r- =0, and

at

u=a, a constant • (c.)

Then, since A and B are not functions of ^, the first of (b.)
cannot subsist unless p be constant. We must therefore
make

dS d^/ / J \

s- + s-="'' (''•'

where c is a constant, and v is the mean motion of the planet,
the first member being of this order.

y ,

If now we divide the first of (b.) by p=l — c-, neglectmg
the powers of- above the first, we have

. d

(sin6B)-(i2-2sin2fi-.2c-sin2AA = 0.

And if in this we neglect the very small quantity 2c - sin* d A,
we have

«4(sin9B)-(i2-2sin2e)A=0. . . . (e.)

From (a.), (c.) and (d.), we have

^ d^ d^ ,^ V

Eliminating B from (e.) by the second of (a.), there results

sin2d^+3sin6cosd^+(l-»2)A=0. . (7.)
Particular integrals of this are, when i—%

k^^a^-\-lQ.o^^-\

sm-

cos^

192 Dr. A. Voelcker on the Chemical Composition of the

and when /=1, Ai = a,5 where a^ and a^ are the values of a
from the first of (6.).

By means of these we easily find the other particular inte-
grals. Let them be hci = bj{^)j Ai=6,/j(9). We shall find
that,/(fi) and/,(fl) are infinite at the pole, and therefore inad-
missible. Consequently we must have 63=0, 6i=0, and

A2=«2(^l+2cos2-j _, A,=ai

cos-

^2= \ -^ (sin ^Aa), Bj = ;^ (sin flAO

(8.)

2 f/e ^ 2y» --1 ^g

where the values of Bg and B, are derived from the second of
(a.), and the arbitraries a^ and «j are functions of r. It is to
be observed that in making Sw a complete variation relative to
6 and vs only, and not to r, we shall lose no terms depending
on r\ for the arbitrary of the integral, not containing cr, and
therefore not <p, must be rejected. And it is to be further
observed, that there are no more solutions than that obtained.

Gunthwaite Hall, near Barnsley, Yorkshire,
July 28, 1849.

[To be continued,]

XXVI. On the Chemical Composition of the Fluid in the Ascidia
o/'Nepenthes. By Dr. A. Voelcker of Frankfort*.

THE watery secretions of certain plants belonging to the genera
Nepenthes, Cephalotus, and Sarracenia, have long attracted
the attention of botanists ; but whilst the secreting organs of these
plants have been minutely described, the chemical nature of the
fluid itself has been but very imperfectly examined. That these
liquids have not met with the attention to which their importance
entitles them, may be accounted for by the circumstance that few
chemists have an opportunity of obtaining the imaltered fluids,
and that even those who are fortunate enough to procure them,
seldom can command a sufficient quantity to enable them to inves-
tigate their nature. With the exception of Dr. Turner's analysis
of the fluid in the ascidia of Nepenthes, I know of no other ana-
lysis of this fluid or of similar secretions. The botanists who
have given attention to the subject of the watery secretions of
the leaves of plants have found these secretions to consist in most
cases of nothing but pure water, and have only occasionally dis-

* From the Annals and Magazine of Natural History, 2d Series, vol. iv.
p. 128.

Fluid in the Ascidia o/" Nepenthes. 193

covered in them some vegetable matter. Treviranus for instance
observed a tasteless water in the corolla of Maranta gibba, which
he however did not further examine; the same gentleman ex-
amined the watery secretion of Amomum Zerumbet, and caused
Dr. Goppert to subject it to chemical analysis, from which it re-
sulted that the fluid between the scales of the spikes consisted of
almost pure water, containing a small quantity of vegetable fibre
and mucus.

The most remarkable instance of a watery secretion from the
leaves of plants is recorded in the ' Annals of Natural History '
for 1848, in a paper by Mr. Williamson, who observed that the
leaves of Caladium destillatorium had the peculiar power of ex-
haling watery fluid from a point near the apex on the upper side.
Each full-grown healthy leaf, according to Mr. Williamson's ob-
servation, produced about half a pint of water during the night,
which, on being analysed, was found to contain a very minute
portion of vegetable matter.

It appeared to me highly improbable that these fluid secre-
tions should consist of pure water with merely a tyace of vege-
table matter, and no inoi'ganic substances whatsoever. If they are
to be regarded as true secretions, we naturally should expect them
to contain some of the salts which we find in all juices of plants.
I was therefore anxious to examine this point, and I am glad that I
have an opportunity of bringing the results of my analysis of the
fluid in the ascidia of Nepenthes before the notice of the Bota-
nical Society. It is through the kindness of Prof. Balfour,
Mr. Evans of the Experimental Gardens, Messrs. Jas. Dickson and
Sons, and Sir W. Hooker, that I have obtained the materials for
the following analysis, and I consider it my duty to express here
publicly my deep sense of gratitude for the kindness and libe-
rality with which the above-named gentlemen have assisted me
in carrying on this inquiry. I have also to express my obliga-
tions to Dr. George Wilson for kindly allowing me the use of
his laboratory.

Linnaeus regarded the ascidia oi Nepenthes as a natural reser-
voir for rain, and thought that the water found in them was intro-
duced from without, and was not secreted by the plant itself.
His opinion however has been contradicted already by many bo-
tanists, especially Treviranus, who observed that the water in the
pitchers of Nepenthes destillatoj'ia is always clear, and that there
exists a distinct secreting apparatus. Treviranus says, in an ar-
ticle which appeared in the ' Edinb. New Philosoph. Journal' for
Oct. 1832— April 1833 :— " The parietes of the leaf of Nepenthes
destillatoria are traversed by a multitude of proportionally large
anastomosing veins, which contain many true spiral vessels. The
upper half of its inner surface is covered with a blue rind, as parts

Phil. Mag. S. 3. Vol. 35. No, 235. Sept. 184-9. O

ID* Dr. A. Voelcker on the Chemical Composition of the

often are which require to be protected from the action of water ;
the under half is, on the contrary, shining and full of gland-like
eminences directed downwards, and having a hole almost visible
to the naked eye, which is uncovered by the cuticle which the
remainder possesses." The watery secretion reaches generally
to the level of these glands in the middle of the ascidium, and he
thinks that they are true secreting organs. This peculiar struc-
ture alone gives a strong reason for thinking that the water in
the ascidia of Nepenthes is supplied by the plant itself, and the
circumstance that water is found in pitchers which have never
been opened is another argument against the supposition that it
comes from without. The subjoined analysis of the fluid more-
over leaves no doubt that it is a true secretion.

Before I enter into the particulars of my experiments I will
mention that I could not detect any oxalic acid in the fluid of
Nepenthes. It is stated in Lindley^s ' Vegetable Kingdom ' that
Dr. Turner found this acid in combination with potash, and that
he also detected a trace of organic matter, which caused the
watery fluid when boiling to emit an odour of boiled apples.
Though I have examined the water of many pitchers from four
different localities, and paid particular attention to the detection
of oxalic acid, I have failed in finding a trace of it, and I am
therefore inclined to believe that Dr. Turner, on account of the
minute quantity of solid matter which he must have got on eva-
poration of the water, was unabk to subject the minute crystals
which he took for superoxalate of potash to a further examina-
tion, which would have shown him that the crystals were not
superoxalate of potash, but chloride of potassium. The propor-
tion of chloride of potassium which I found in the fluid is consider-
able ; it is deposited from the liquid after evaporation in the form
of minute but very regular cubes. The odour of boiled apples
which Dr. Turner observed I found very distinct when the water
was heated to the boiling-point. Besides chloride of potassium I
found malic and a little citric acid, in combination usually with
soda, lime and magnesia, and a small quantity of another orga-
nic matter which gave a yellow tint to the water during its eva-
poration. The quantity of the latter was too minute to enable
me to ascertain its chemical nature.

I will now proceed to describe the experiments with the dif-
ferent fluids in the ascidia of Nepenthes : —

1 . Fluid from an unopened pitcher-plant grown in the Bota-
nical Garden, Edinburgh.

The water which I got on the 12th of June, 1849, was per-
fectly colourless and clear ; it had an agreeable, not very pro-
nounced smell and a refreshing taste. Though its taste was not
sour, litmus paper showed the presence of an acid or an acid salt

Fluid in the Ascidia o/* Nepenthes. 195

by the red colour it assumed when dipped in the water. When
heated it remained clear, and only assumed a slightly yellow
colour when the liquid became very concentrated. The residue
which remained on evaporation was cream-coloured, very hygro-
scopic, and dissolved entirely in a small quantity of distilled
water. Litmus paper plunged in this solution was turned red
immediately ; the acid which is present in the water therefore was
not volatilized during the evaporation.

The quantity of the water from one pitcher amounted to

17*41 grains,
which gave on evaporation

0-16 of dry residue, dried at 312° F.
100 parts of the fluid consequently contained

0*92 per cent, of solid matter.

2. "Water from unopened pitcher-plants grown in the Botani-
cal Garden, Edinburgh, June 13th, 1849.

The physical characters were the same as those of the preceding
liquid. Litmus paper likewise was turned red when dipped in
the water.

The behaviour of the water towards chemical tests was as fol-
lows : —

Ammonia produced no change.

Carbonate of ammonia produced no change.

Lime-water produced no change.

Chloride of calcium and ammonia produced no change.

Nitrate of barytes produced no change.

Nitrate of silver gave a white voluminous precipitate, inso-
luble in nitric acid, but soluble in ammonia.

Acetate of lead produced a white precipitate soluble for the
greater part in boiling water.

Basic acetate of lead gave a white voluminous precipitate in
the clear liquid filtered from the precipitate which was caused by
neutral acetate of lead.

Oxalate of ammonia produced a small white precipitate of
oxalate of lime.

Phosphate of soda and ammonia, added to the concentrated
liquid filtered from the oxalate of lime, gave a crystalline white
precipitate of phosphate of magnesia and ammonia.

Chloride of platinum, added to the water after having been
evaporated to a small bulk, produced a crystalline yellow preci-
pitate.

The residue left on evaporation of the water coloured the alco-
hol flame yellow.

These reactions indicate the presence of chlorine, potash, soda,
magnesia, lime and organic acids, and prove the absence of other

0 2

196 Dr. A. Voelcker on the Chemical Composition of the

bases and of sulphuric acid, tartaric acid, racemic acid, oxalic and
phosphoric acid.

3. Fluid from unopened pitcher-plants grown in the Experi-
mental Gardens, Edinburgh, June 13th, 1849.

The water was perfectly clear and colourless, had an acid re-
action on litmus paper, and exhibited the same physical and che-
mical characters as the fluid from the pitcher-plants of the Bota-
nical Garden.

63"21 grains of water left on evaporation a residue which, dried
at 312° F., amounted to

0*58 grain.
100 parts of the fluid therefore contained

0*91 per cent, of dry residue.

Exposed to a red heat the residue (0'58 gr.) turned black, and
gave off pungent fumes, and left a white ash after all the char-
coal was completely burnt away, the weight of which was 0*42
of a grain.

The loss by burning therefore was 25'86 per cent.

The residue left on evaporation of this fluid was slightly co-
loured, and gave an almost colourless solution with water. A
portion of this solution M^as kept in a closed bottle. After the
lapse of a fortnight the water in the bottle became turbid and
deposited some light white flakes. The acid reaction, which was
very distinct before, had now disappeared entirely.

4. Fluid from opened pitcher-plants grown in the Experi-
mental Gardens, June 14th, 1849.

The fluid in the open pitchers was coloured yellow, but other-
wise perfectly clear. The reactions with chemical tests were the
same as the preceding.

97-74 grains of water left on evaporation 0*85 of a grain of
dry residue.

100 parts therefore contained 0*87 per cent, of solid matter.

This residue was coloured yellow, but redissolved entirely in a
little water.

5. Fluid from unopened pitcher-plants grown in Messrs.
Dickson's nursery, June 17th, 1849.

Fluid perfectly clear and colourless, reactions the same as above.
319'48 grains left a residue which, dried at 212° F., was found
to weigh 1-88 grain; or

100 parts of the liquid contained 0*58 per cent.

6. Liquid from unopened pitcher-plants grown in Messrs. Dick-
son's nursery, June 21st, 1849.

Physical and chemical characters of the liquid the same as
above.

193-82 grains of water left on evaporation 1*22 grain of dry
residue, or 0-62 per cent.

Fluid in the Ascidia o/' Nepenthes. 197

When burnt the 1*22 gi-ain lost in weight 0-44 of a grain,
or 100 parts of the residue lost 3606 per cent.

The solid matter of this liquid was very hygroscopic, and co-
loured more yellow than that of the Botanical and Experimental
Gardens. 1 found that the total weight of the solid matter in this
fluid was not so large as in that of the Experimental Gardens, but
that the proportion of organic matter in the residue was larger
than that in the residue of the fluid procured from the Experi-
mental Gardens.

7. Water from opened pitcher- plants grown in Messrs. Dick-
son's nursery, June 24th, 1849.

This fluid was yellow-coloured and not quite clear. Litmus
paper was turned red when moistened with the water. The re-
actions were the same as above, with the exception that nitrate of
barytes produced a slight turbidity, indicating the presence of
sulphuric acid. As I found no sulphuric acid in the liquid from
the unopened pitchers of the same plants, nor in any of the
liquids I examined, I think the sulphuric acid which I found
must have resulted from the water with which the plants had
been watered which had found its way into the open pitchers*.
In order to see if the liquid contained any volatile acid, I sub-
jected about half an ounce of it to distillation. The distillation
was continued till the residue in the glass retort was evaporated
to dryness, and the generated steam carefully condensed in a
glass receiver. The distilled portion was perfectly pure water,
and experienced no change by any reagent.

It results from this experiment that the liquid in the ascidia
of Nepenthes does not contain any volatile acids, such as acetic or
formic acid.

8. Fluid from unopened pitcher-plants grown in the Royal
Gardens, Kew.

Having been unable to detect any oxalic acid in the above-
mentioned fluids, I was anxious to ascertain whether or not the
fluid of plants grown in other localities contained oxalic acid. I
therefore applied to Sir W. Hooker, who with great liberality di-
rected some liquid of unopened pitcher-plants grown in the Kew
Royal Botanical Gardens to be sent to me. The physical and
chemical characters of this fluid were precisely the same as those
of the previously examined liquids. The proportion of solid
matter it held in solution however was much smaller.
299*87 grains of the liquid left on evaporation only

0*82 of a grain of diy residue.
100 parts of the liquid therefore contained

0'27 per cent, of solid matter.

* The water in this instance was procured chiefly from the Water of Leith.

198 Dr. A. Voelcker on the Chemical Composition of the

On burning, the 0-82 of a grain lost 0*27 of a grain, or
100 parts lost 32'92 per cent.

All the liquids from the different localities above-mentioned
which were left over I mixed together and evaporated the mix-
ture to dryness. One-half of the dry residue I exposed to a red
heat, and used the remaining white ash for the determination of
the inorganic salts of which it was composed.

The other half I dissolved in water and precipitated with basic
acetate of lead, in order to obtain the organic acids in combina-
tion with lead. This precipitate I collected on a filter and washed
with cold distilled water. It was then removed from the filter
and suspended in water, through which a current of sulphuretted
hydrogen was passed. By this means I separated the lead as
sulphuret, and obtained the organic acids free dissolved in water.
This solution was colourless and very acid ; evaporated to a small
bulk in a water-bath it assumed a yellow colour, and dried at last
to a yellow crystalline mass, which deliquesced in the air and dis-
solved readily in water and alcohol, leaving behind a trace of a
brown organic matter.

Lime-water added in excess to a portion of the acid solution
produced no precipitate in the cold, but on boiling a small white
precipitate fell down which redissolved entirely in sal ammoniac.

Chloride of calcium and ammonium left the liquid unchanged
in the cold, but on boiling a precipitate was formed which was
soluble in sal ammoniac.

Acetate of lead gave a white precipitate insoluble in ammonia,
soluble in acetic acid.

Basic acetate of lead added to the liquid filtered from the pre-
cipitate caused by neutral acetate of lead produced another abun-
dant white precipitate. From these reactions it appears that the
precipitate with lime-water was caused by citric acid and not by
tartaric or racemic acid, the reactions of which acids are similar
to those of citric acid, for tartrate of lime is not soluble in sal
ammoniac, whilst tartrate of lead redissolves readily in ammonia.
Tartaric acid moreover is sufficiently characterized by the sparing
solubility of its acid potash salt, and as the acid liquid did not
give rise to the formation of such a salt with potash, we have
another indirect proof of the presence of citric acid. A little
tartaric acid added to the liquid in which tartaric acid was sought
in vain, after a few minutes produced the sparingly soluble pot-
ash salt.

Racemic acid is thrown down both by lime-water and by a
solution of gypsum ; the acid liquid of Nepenthes remained un-
changed by either reagent, hence it cannot have contained any
racemic acid.

The precipitate caused by chloride of calcium and ammonia

Fluid in the Ascidia c/' Nepenthes. 199

and boiling was filtered hot, and alcohol and ammonia added to
the clear liquid. The addition of alcohol produced a voluminous
white precipitate, a reaction which indicates the presence of malic
acid. The quantity of this precipitate was much larger than that
of the lime precipitate which citric acid gave. The formation of
a precipitate, upon addition of alcohol to the liquid from which
the first had been separated by filtration, is chai'acteristic of the
presence of malic acid, for no other lime-salts were present ; for
instance, no sulphate of lime was present which could have pro-
duced a precipitate. But I thought it nevertheless necessary
to examine the precipitate caused by the addition of alcohol
further. When burnt it turned black, gave off pungent vapours,
and was converted into carbonate of lime. The solution of chlo-
ride of calcium and ammonia used for the experiment remained
clear after the addition of alcohol ; the acid liquid likewise re-
mained clear when alcohol was added ; both put together imme-
diately produced a white voluminous precipitate.

Basic acetate of lead, as already mentioned, throws down from
the solution a white precipitate. I could not observe that this pre-
cipitate melted below the boiling-point of water, as pure malate of
lead does, but it must be remembered that this reaction is di-
stinctly marked only when the malate of lead is pure ; admixtures
of other salts of lead prevent it altogether ; and as I have shown
the presence of citric acid and another organic substance which
is thrown down by basic acetate of lead, there can be no doubt
that this was the reason why the precipitate did not dissolve in
boiling water.

Though I have not been able to obtain a sufficient quantity of
the acids oi Nepenthes for an elementary analysis, I think the above
reactions prove the presence of malic and citric acid. Oxalic acid,
which is readily detected, as the weakest solution of an oxalate is
thrown down by lime-water, I failed to discover; on the contrary, I
have shown that the water contained lime, which excludes the co-
existence of oxalic acid in a clear liquid. I have found that the
smallest quantity of oxalic acid immediately caused the water of
Nepenthes to become turbid.

The second half of the residue left on evaporation of the mixed
fluids I exposed to a red heat in a platinum capsule. It turned
black, gave off pungent fumes, and left a white salt after all the
charcoal was burnt off.

On analysis this residue was found to consist of

Chloride of potassium 76-31

Carbonate of soda 16'44

Lime 3-94

Magnesia 3*94

100-63

200 Sir W. Rowan Hamilton on Quaternions*

The unburnt residue left on evaporation of the fluid in the
ascidia of Nepenthes therefore consists, if we take the average of
the loss of the three determinations at 31'61 per cent, and reject
the carbonic acid of the ash, of —

Organic matter, chiefly

Malic acid and a little citric acid . 38*61

Chloride of potassium .... 50*43

Soda 6-36

Lime 2-59

Magnesia 2*59

100-57

It is remarkable that none of the fluids which I examined
contained any sulphuric acid, which acid has been found in all
juices of plants, and which I do not doubt also exists in the sap
of Nepenthes. An ash analysis of this interesting plant would
show the proportion of sulphuric acid at once ; and as we are not
in possession of an analysis of the ash of Nepenthes, which in
other respects might be of interest, I take the liberty of asking
those gentlemen who are in the possession of Nepenthes' plants
to preserve the clippings of branches, &c., which I shall be glad
to receive as materials for an ash analysis.

XXVII. On Qiiaternions ; or on a New Si/stem of Imaginaries
in Algebra. By Sir William Rowan Hamilton, LL.D.^
M.B.I.A.^ F.R.A.S., Corresponding Member of the Insti-
tute of France^ Sfc., Andrews' Professor of Astronomy in the
University of Dublin ^ and Royal Astronomer of Ireland.

[Continued from p. 137.]

86. nnHE same sort of quaternion analysis, proceeding from
-I- the formulae in art. 82*, and from others analogous
to them, has conducted the author to many other geometrical
theorems, respecting the inscription of gauche polygons in
surfaces of the second degree. An outline of some of these
was given to the Royal Irish Academy in June 1849; and
some of them may be mentioned here. To avoid, at first,
imaginary t deformations, in passing from an original sphere,

* In art. 84, last line of page 135,/or a tangential vector, r<°arf an arbi-
trary tangential vector.

In art. 85, fifth line from foot of page 136, for inscribed polygon of 2»i
sides, rearf inscribed polygon of 2vi-\-\ sides.

f While acknowledging, as the author is bound to do, the great courtesy
towards himself that has been shown by several recent and able writers, on
subjects having some general connexion or resemblance with those on which

Sir W. Rowan Hamilton o?i Quaternions. 20l

the surface in which the polygons are inscribed shall be sup-
posed, for the present, to be an ellipsoid. Results of the same
general character, but with some important modifications,
(connected with the ordinary square root of negative unity,)
hold good for the inscription of such polygons in other surfaces
of the same order, as the writer may afterwards point out.
He is a\\'^re, indeed, that the corresponding class of questions,
respecting the inscription of pla?ie polygons in conies, has
attained sufficient celebrity; and feels that his own acquaint-
ance with what has been already done in that department of
geometrical science is inferior to the knowledge of its history
possessed by several of his contemporaries, for instance, by
Professor Davies. He knows also that some of the published
methods for inscribing in a circle, or plane conic, a polygon
whose sides shall pass through the same number of given
points, can be adapted to the case of a polygon formed by arcs
of great circles on the surface of a sphere, and inscribed in a
spherical conic ; and he has, by quaternions, been conducted
to some such methods himself, for the solution of this latter
problem. But he acknowledges that he shall feel some little
surprise, though perhaps not entitled to do so, if it shall turn
out that the results of which he proceeds to give an outline,
respecting the inscription of rectilinear hut gauche polygo7is in
an ellipsoid, have been wholly (or even partially) anticipated.
They have certainly been, in his own case, results of the ap-
plication of the quaternion calculus : but whatever geometrical
truth has been attained by any one general mathematical me-
thod (such as the Quaternions claim to be), may also be found,
or at least proved, by any other method equally general. And
those who shall take the pains of proving for themselves, by

he has been engaged, he hopes that he may be allowed to say, — yet rather
as requesting a favour than as claiming a right, — that he will be happy if
the inventor of the Pluquaternions shall consent to his adopting or rather
retaining a wordy namely " biquaternion," which the Rev. Mr. Kirkman
has indeed employed, with reference to the octaves of Mr. J. 1\ Graves and
Mr. Cayley, but does not appear to want, for any of his own purposes :
whereas Sir W. Rowan Hamilton has for years been accustomed to use
this word Biquaternion,— though perhaps hitherto without printed publi-
cation,— and indeed could not, without sensible inconvenience, have dis.
pensed with it, to denote an expression entirely distinct from those octaves,
namely one of the form

where -v/ — 1 is the old and ordinary imaginary of algebra (and is therefore
quite distinct from t,j, k), while Q and Q' are abridged symbols for two
different qicaternions of the kind w^ix-'rjy-\-kz, introduced into analysis in
1843. Biquaternions o^ this sort have repeatedly ybrcerf themselves on the
attention of Sir W. R. H., in questions respectmg geometrical impossibility,
ideal intersections, imaginary deformations, and the like.

203 Sir W. Rowan Hamilton on Quaternions.

the Cartesian Coordinates, or by some less algebraical and
more purely geometrical method, the following theorems (if
not already known), which have thus been Jbwid by the Qua-
ternions, will doubtless be led to perceive ma7ii/ new truths,
connected with them, which have escaped the present writer ;
although he too has arrived at other connected results, which
he must suppress in the following notice.

87. I. An ellipsoid (e) being given, and also a system of any
even number of points of space, Aj, Ag, .. A^mi of which points
it is here supposed that none are situated on the surface of the
ellipsoid ; it is, in general, possible to iiiscribe in this ellipsoid,
two, and only iwo, distinct and real polygons of 2m sides,
BBj . . B^OT-i and b'b'i . . B'2,ra_i, such that the sides of each of
these two polygons (b)(b') shall pass, respectively and success-
ively, through the 2m given points ; or in other words, so that
BAjBi, B1A2B2, ... B2„j_iA2mB, and also b'AjB'i, B'jAgB'g, ... b'2^_,
A2otB', shall be straight lines; while b, Bj, ... B2m-i) and also
b', b'j, ... b'2to-ij shall be points upon the surface of the ellip-
soid.

[It should be noted that there are also, in general, what
may, by the use of a known phraseology, be called two other,
but geometrically^ imaginary, modes of inscribing a polygon,
under the same conditions, in an ellipsoid: which modes may
become real, by imaginary deformation, in passing to another
surface of the second order.]

II. If we now take any other and variable point p on the
ellipsoid (e) instead of b or b', and make it the first cotmer of
an inscribed polygon of 2m + 1 sides, of which the frst 2m
sides shall pass, respectively and successively, through the 2m
given points (a); in such a manner that pAjP^, PiA^Pj* •••
P2OT-1 A2,„ P2„i, shall be straight lines, while p, Pj, Pg, ... v^m
shall all be points on the surface of the ellipsoid : then the last
side, or closing chord, P2toP> of this new and variable polygon
(p), thus inscribed in the ellipsoid (e), shall touch, in all its
positions, a certain other ellipsoid (e').

III. This new ellipsoid (e') is itself inscribed in the given
ellipsoid (e), having double contact therewith, but being else-
where interior thereto.

IV. The two points of contact of these two ellipsoids are the
points B and b'; that is, they are ihe first corners of the two
inscribed polygons of 2m sides, (b) and (b'), which were con-
sidered in I.

[So far, the results are evidently analogous to known theo-
rems, respecting polygons in conies; what follows is more
peculiar to space.]

V. If the two ellipsoids, (e) and (e'), be cut by any plane

Sir W. Rowan Hamilton on Quaternions. 203

parallel to either of their two common tangent planes, the
sections will be two similar and similarly situated ellipses.

[For example, if the original ellipsoid reduce itself to a
sphere, then the two points o^ contact, b and b', become two of
the four urnbilics on the itiso'ibed ellipsoid.]

VI. The closing chords pp^,,, are also tangents to a certain
series or system of curves (c'), not generally plane, on the sur-
face of the inscribed ellipsoid (e') ; and therefore may be
arranged into a system of developable surfaces, (d'), of which
these curves (c') are the aretes de rebroussement.

VII. The same closing chords may also be arranged into
a second system of developable surfaces, (d"), which envelope the
inscribed ellipsoid (e') and have their aretes de rebroussement
(c") all situated on a certain other surface (e"), which is, in its
turn, enveloped by ihe first set of developable surfaces (d') ;
so that the closing chords vv^m a^e all tangents to a secojid
set of curves, (c"), and to a second surface, (e").

VIII. This second surface (e") is a hyperboloid of fwo sheets,
having double contact with the given ellipsoid (e), and also
with the inscribed ellipsoid (e'), at the points b and b'; one
sheet having external contact with each ellipsoid at one of
those two points, and the other at the other.

IX. If either sheet of this hyperboloid (e") be cut by a
plane parallel to either of the two common tangent planes, the
elliptic section of the sheet is similar to a parallel section of
either ellipsoid, and is similarly situated there'voith.

[For example, the points ot contact b and b' are two of the
umbilics of the hyperboloid (e"), when the given surface (e) is
a sphere.']

X. The centres of the three surfaces, (e) (e') (e"), are situ-
ated on one straight line.

XI. The two systems of developable surfaces, cut the ori-
ginal ellipsoid, (e), in two new series of curves, (f'), (f"), not
generally plane, which everywhere so cross each other on (e),
that at any one such point of crossing, p, the tangents to the
two curves (f') (f'') a^-e parallel to two conjugate semidiamefers
of the surface (e) on which the curves are contained.

[For example, if the original surface (e) be a sphere, then
these two sets of curves (f') (f") cross each other everywhere
at right angles, upon that spheric surface.]

XII. Each closing chord pPa^ is cut harmonically, at the two
points, c^ c", where it touches the inscribed ellipsoid (e'), and
the exscribed hyperboloid (e") ; or xiohere it touches the curves
(c') and (c").

XIII. The closing chords, or the positions of the last side of
the variable polygon (p), are not, in general, all cut perpendicu-

204 Dr. Schunck on Colouring Matters.

larly by any one common surface (notwithstanding the analogy
of their arrangement, or distribution in space, in many respects,
to that of the normals to a surface). In fact, the two systems
of developable surfaces, (d') and (d"), are not generally rect-
angular to each other, in the arrangement here considered,
though they are so for any system of normals.

XIV. Through any given point of space, A2m+i» which is at
once exterior to the inscribed ellipsoid (e'), and to both sheets
of the exscribed hyperboloid (e"), it is in general possible to
draw two, and 07ily two, distinct and real straight lines, p'p'2m
and p"p"2mj of which each shall touch at once a curve (c') on
(e'), and a curve (c") on (e"), and of which each shall coincide
isoith one of the positions of the closing chord, pP2,„ ; in such a
manner as to be the last side of a rectilinear polygon of 2m + 1
sides, p'p'jP'a . . p'2m5 or p"p"^p"2. . p"2,n) inscribed in the given
ellipsoid (e), under the condition that its sides shall pass, re-
spectively and successively, through the 2m + 1 given points,
AjAg . . A2mA2TO+i. But if the last of these points were given on
either of the two enx)eloped surfaces, (fJ), (e"), the problem of
such inscription would in general admit of only one distinct
solution, obtained by drawing through the given point the
tangent to the particular curve (c') or (c"), on which that
point was situated. And if the last given point A2m+i were
situated within the inscribed ellipsoid (e'), or within either
sheet of the exscribed hyperboloid (e"), the problem of the
inscription of the polygon of 2m + 1 sides would then become
geometrically impossible: though it might still be said to admit,
in that case, o^ two imaginary modes of solution.
[To be continued.]

XXVIII. On Colouring Matters. By Edward Schunck*.

IN the report which I had the honour of presenting last year to
the British Association on Colouring Matters, I gave the results
of my investigation of the colouring matters of madder. This in-
vestigation I have continued and brought to a conclusion. The sub-
ject has however proved so extensive, the number of questions
arising in regard to this valuable and extensively-used tinctorial sub-
stance being very great, tliat I have been unable to examme any other
colouring matters very minutely.

I stated in my last report, that when finely-ground madder roots
are treated with hot water, a brown liquid is obtained having a
sweetish bitter taste, in which acids produce a dark brown precipi-
tate. This precipitate I stated to consist of six substances, viz. two
colouring matters, two fats, pectic acid and a bitter substance. To
these I now add a seventh : it is a dark brown substance which re-
• From the Report of British Association for 1848.

Dr. Schunck on Colouring Matters. 205

mains behind when the other substances have been removed by
means of boiling water and alcohol ; it is soluble in caustic alkalies
with a dark brown colour, and seems to be the substance lo which
the colour of the dark brown precipitate is due : I consider it to be
oxidized extractive matter. Concerning the method of separating
the other six substances contained in the dark brown precipitate, I
have nothing to add to what I said in my last report, as I have not
been able to discover a shorter or better plan of separating them
than that which is there described. In regard to their nature, pro-
perties and composition, which I have examined more minutely, I
shall in this report give a number of additional details ; before
doing so however I shall make a few observations on the subject in
general. I may state, in the first place, that I have arrived at the
conclusion that there is only one colouring matter contained in mad-
der, viz. alizarine ; the other substance, which I took for a colouring
matter in the first instance, and which I called rubiacine, I now con-
sider to be no colouring matter at all, for reasons which I shall pre-
sently state. I have also reason to believe that the two substances
which in my first report I called fats, are not fats, but resins ; they
are coloured resins similar to many others known to chemists. Of
these two resins I shall call the more easily fusible one, which dis-
solves in a boiling solution of perchloride or pernitrate of iron, the
alpha-resin ; the other less easily fusible one, which forms an inso-
luble compound when treated with perchloride or pernitrate of iron,
the beta-resin. The method of preparing them is the same as that
which I described in my former report. After the dark brown pre-
cipitate produced in a decoction of madder by acids has been succes-
sively treated with boiling water and boiling alcohol, there remains
behind a dark brown substance ; on treating this substance with
caustic potash, it dissolves in great part with a dark brown colour ;
on filtering there remains on the filter a mixture of peroxide of iron
and sulphate of lime ; on adding a strong acid to the filtered liquid
a substance in dark brown flocks is precipitated, which is thrown on
a filter, washed and dried. This substance, when heated on platinum
foil, burns without much flame, and leaves a considerable ash. It
is easily decomposed by boiling dilute nitric acid, which converts it
with an evolution of nitrous acid into a yellow flocculent substance.
As it is insoluble in all menstrua except the alkalies, it n)ay be
asked, how it can be extracted from madder by means of boiling
water, in which it is of itself insoluble, and whether it is not pos-
sible that it may be formed during the process of boiling by the
action of the air on some substance contained in the extract. I think
the latter supposition very probable, and 1 shall presently describe
a substance of almost identical properties formed by the action of
the air on xanthine, the extractive matter of madder. 'J'here can how-
ever be no doubt that the brown colour of the precipitate, which is
produced by acids in a decoction of madder, is due to this substance,
for the other bodies contained in it are not brown, but yellow or
orange -coloured in a precipitate state. This dark brown precipitate

206 Dr. Schunck on Colouring Matters.

therefore consists of the following substances : — alizarine, rubiacine,
alpha-resin, beta-resin, riibian, pectic acid, and oxidized extractive
matter.

I have examined the liquid filtered from the dark brown precipi-
tate produced by acids more minutely since making my last report.
Tf oxalic acid be used as the precipitant, the excess of acid may
afterwards be removed by chalk, without leaving any lime-salt in
solution. The liquid, which had a light yellow colour, was evapo-
rated on the sand-bath. During evaporation it gradually became
brown, and left at last a thick dark brown syrup, which never became
dry, however long it might be exposed to the heat of the sand-bath.
On redissolving this syrup in water, a considerable quantity of a dark
brown powder remained behind. On again evaporating the filtered
solution on the sand-bath, an additional quantity of this powder was
deposited, just as in the case of extractive matter. There can be no
doubt that this powder is formed by the action of the air, assisted by
heat, on some soluble substance contained in the liquid. On burning
a small quantity of the brown syrup in a crucible it swelled up
enormously, and gave off a quantity of empyreumatic products,
which burned with a flame, leaving at last a considerable quantity of
white ash ; this ash was partly soluble, partly insoluble in water. The
soluble part had a strong alkaline reaction ; it consisted of a trace of
lime and magnesia, and a great deal of potash, combined with
carbonic, sulphuric and muriatic acids. The insoluble part consisted
of carbonate of lime, carbonate of magnesia, a trace of alumina, phos-
phate of lime and phosphate of magnesia. The solution of the
brown syrup in water had an acid reaction. It gave no precipitate
or peculiar colour with a persalt of iron, and therefore contained no
tannic acid. The addition of alcohol produced no precipitate or
coagulate, and therefore there was no gum present. On adding
muriatic or sulphuric acid to it, and then boiling, it becanne dark-
coloured and deposited a green powder. Sugar of lead produced
in the solution a dirty brown flocculent precipitate, and basic ace-
tate of lead a still more copious precipitate. A considerable quan-
tity of the brown syrup was dissolved in water, and basic acetate
of lead was added until no more precipitate was produced. The
precipitate was separated by filtration, and washed with water.
The percolating liquid had a yellow colour. The excess of lead was
removed from it by sulphuretted hydrogtn, and the filtered liquid
was evaporated over sulphuric acid, since, if evaporated by the as-
sistance of heat, the substance contained in it was changed by the
air, became brown, and deposited a brown powder. After remain-
ing over sulphuric acid for several weeks, there was left a yellow
or brownish-yellow syrup like honey, which did not become dry.
This substance, though not pure (as it contained salts of lime, mag-
nesia and potash), I conceive to be identical with Kuhlmann's xan-
thine and Runge's madder-yellow.

If madder contains sugar, it is evident that, provided the method
of operating described above be followed, it must be contained in

Dr. Schunck on Colouring Matters. 207

the same liquid as this xanthine. I have however not been able to
prove its presence by direct experiment ; but I have succeeded in
ascertaining indirectly that madder does in reality contain sugar of
some kind by means of the following experiment. Half a hundred-
weight of madder was treated with boiling water for several hours.
The liquor, after being reduced by boiling to a convenient com-
pass, was mixed with some yeast, and allowed to ferment. By
distillation an alcoholic liquid was obtained, which, after a second
distillation, gave 2\\ ozs. of alcohol of sp. gr. 0'9S5, which is equi-
valent to 9 ozs. of absolute alcohol. It is therefore evident that
madder contains sugar of some kind or other.

The precipitate produced by basic acetate of lead in the solution
of the brown syrup was decomposed with sulphuretted hydrogen.
The filtered liquid was evaporated, and left after evaporation a dark
brown syrup, having a strongly acid taste and reaction. The brown
colour was no doubt due to xanthine in its oxidized state. After
being repeatedly dissolved, and the solution being each time evapo-
rated, a dark brown powder was deposited, just as in the case of the
original solution : nevertheless the acid taste always remained. It
might be supposed that this taste was due to some vegetable acid ;
and indeed if any such acid, or the compound of any one with the
alkalies or earths, had been extracted from the madder by boiling
water, it would most probably have been precipitated by the basic
acetate of lead, and it would be in the liquid obtained by the decom-
position of the lead precipitate that we should have to look for any
such acid. Now the syrup obtained after decomposing the lead
precipitate and evaporating the liquid, though intensely acid, con-
tained no oxalic, tartaric, malic or citric acid ; neither did it show
the least sign of crystallization ; but the watery solution gave a cry-
stalline precipitate with ammonia and sulphate of magnesia ; and
after destroying the brown organic matter contained in it by adding
nitric acid and boiling, and then evaporating to drive away the
excess of nitric acid, it gave a yellow precipitate with nitrate of
silver and ammonia. I therefore infer that the acid to which the
sour taste of the brown syrup was owing, was phosphoric acid*.
The sulphuret of lead, produced by the decomposition of the lead
precipitate, was treated with boiling caustic potash. A dark brown
solution resulted, which after filtration gave with muriatic acid a
dark brown precipitate. This precipitate, after filtration, washing
and drying, cohered into masses, which were brittle and black, but
became brown when powdered. It was totally insoluble in boiling
water and alcohol. It was decomposed by dilute boiling nitric acid,

* On one occasion, after having added nitric acid to the acid syrup and boiled,
I obtained on evaporation crystals of an organic acid, very similar to alizaric acid,
but not identical with it. It was sparingly soluble in cold water, but very soluble
in hot. It was volatile. The watery solution gave with acetate of lead a cry-
stalline precipitate soluble in boiling water, with perchloride of iron a cream-
coloured precipitate, with acetate of copper a green crystalline precipitate, and with
nitrate of silver and ammonia a white flocculent precipitate. Alizarate of lead is
quite insoluble in boiling water, and not in the least crystalline.

208 Dr. Schunck on Colouring Matters.

and changed into a yellow flocculent substance. It was soluble in
concentrated sulphuric acid, forming a brown liquid, and was re-
precipitated by water. I consider this substance, that formed in a
solution of xanthine during evaporation by heat, and the dark brown
substance contained in the precipitate produced by acids in a decoc-
tion of madder as the same, and that they are all produced from
xanthine by the action of the oxygen of the air.

It still remains for me to say a few words on the substances left
behind in the root, after madder has been exhausted with boiling
water. It has for some time been well known that if madder, which
has already been used for the purpose of dyeing, be treated with a
strong acid such as sulphuric or muriatic, and the acid be then
carefully removed by washing with cold water, it is capable of being
again used for dyeing in the same way as fresh madder. It is in this
manner that the article known in commerce as garanceux is manu-
factured. This is a convincing proof that it is impossible to extract
the whole of the colouring matter by means of boiling water, and
that part of it must remain behind in some state in which it is inso-
luble in water. A quantity of madder was treated with boiling
water until the liquor gave absolutely no more precipitate on the
addition of muriatic acid. A very long boiling was necessary for
this purpose. The colour of the madder was changed by this
process from yellowish-brown, as it appears in the fresh state, to
a dull red. It was then treated with boiling caustic potash ley. A
liquor of a brownish colour was obtained, in which muriatic acid
produced a gelatinous precipitate of a brown colour. This was se-
parated by liltration, and, after being washed with cold water in
order to remove all the muriatic acid, was treated with a large
quantity of boiling water, in which it proved to be almost entirely
soluble. The solution was light brown. It gave gelatinous preci-
pitates with acids, with lime and baryta water, alcohol and most
salts. On evaporation it left a substance in light brown, transpa-
rent, brittle scales, which turned out to be pectic acid, much purer
indeed than that obtained in the first instance from the aqueous de-
coction. No colouring matter, or any other substance besides pectic
acid, seemed to be extracted by the caustic alkali.

Another quantity of madder which had been completely ex-
hausted by boiling water, was treated with boiling muriatic acid, and
the liquid, after the boiling had been kept up for some time, was
strained through a cloth and supersaturated with ammonia, which
produced a pinkish-white precipitate. This precipitate was thrown
on a filter and carefully washed. The liquid contained an abun-
dance of lime and magnesia, A part of the pinkish-white precipitate
was dried and heated to redness in a crucible. During ignition a
gas came off which was without odour, and burnt with a blue flame,
being probably carbonic oxide. After complete ignition it dissolved
in muriatic acid with an effervescence of carbonic acid, but without
leaving much carbonaceous residue. On adding ammonia to the
solution a white precipitate was again produced. The filtered liquid

Dr. Schunck ofi Colouring Mailers. 209

contained a large quantity of lime and a trace of magnesia. The
precipitate consisted of alumina, peroxide of iron, phosphate of lime,
and a trace of phosphate of magnesia. As it became probable from
the preceding reactions that the pinkish-white precipitate contained
oxalate of lime, the rest of it was treated with boiling dilute sulphuric
acid. The liquid after filtration was evaporated. It gave crystals
which were dissolved in alcohol to separate the sulphate of lime.
The alcohol on evaporation gave colourless crystals of pure oxalic
acid. Hence I infer that the following substances were extracted
from the madder by means of muriatic acid : — lime, magnesia, oxa-
late of lime, phosphate of lime, alumina and peroxide of iron. The
madder which had been subjected to the action of muriatic acid was
now well-washed with water, and then treated with boiling caustic
potash ley. A dark red solution was obtained, which, after being
strained through a cloth', produced, on being supersaturated with an
acid, a dark reddish-brown precipitate. This precipitate was thrown
on a filter, and well-washed with cold water, to remove the excess
of acid. 1 found this precipitate to dye mordanted cloth quite full,
and of the same colours as madder itself. There could therefore
be no doubt about its containing alizarine. Moreover on treating
the precipitate with boiling alcohol, a brownish-yellow liquid was
obtained, which left on evaporation a brownish-red residue. A
small portion of this residue being heated between two watch-
glasses, an abundance of orange- coloured crystals of sublimed aliza-
rine appeared on the upper glass. By treating the precipitate with
boiling water, and filtering boiling hot, the liquid deposited on
cooling orange-coloured flocks, which were impure alizarine, for they
dyed mordanted cloth, and after being dried and heated in a tube,
they gave a crystalline sublimate. The liquid gave on evaporation
pectic acid. That part of the precipitate which was left undissolved
by boiling water, was treated with a boiling solution of nitrate of
iron. The filtiered liquid gave, on the addition of muriatic acid, a
slight yellow precipitate, which was probably rubiacic acid from the
rubiacine of the precipitate. The greater part was insoluble in ni-
trate of iron. By treating the insoluble residue with boiling mu-
riatic acid, filtering, washing with water, and treating with boiling
alcohol, an abundance of beta-resin was procured.

I infer from these experiments that the substances extracted from
madder by caustic potash, after exhaustion with boiling water and
treating with acid, previously existed in the root in combination with
lime and magnesia ; that these substances are not different from
those extracted by boiling water, viz. alizarine, rubiacine, resins and
pectic acid ; that the compounds of these bodies with lime and mag-
nesia are insoluble in water, and, with the exception of pectate of
lime, insoluble in caustic alkalies ; and that therefore, in order to
extract them by means of water or an alkali, it is first necessary to
remove the lime and magnesia with which they are combined by
means of an acid.

I shall now proceed to give some further details concerning the
properties and composition of the substances extracted from madder.

Phil. Mag. S. 3. Vol. 35. No. 235. Sept. 18*9. P

210 Dr. Schunck on Colouring Matters.

Alizarine. — Concerning the properties of alizarine I have nothing
to add to what I stated in my last report, except that when crystal-
lized from alcohol it contains several atoms of water of crystalliza-
tion, which it loses when heated to 212° F. The crystals after being
heated to this point have not lost their shape, but have become
opake and of a much redder colour, resembling that of native
chromate of lead. On placing them in a tube immersed in a sul-
phuric-acid bath, and heating the bath, no further change takes place
until about 420° F., when a sublimate of orange-coloured crystals
begins to appear on the cold part of the tube.

On subjecting alizarine to elementary analysis I obtained the
following results : —

I. 0*3205 grm. of crystallized alizarine dried in theairgave,on being
burnt with chromate of lead, 0*6695 carbonic acid and 0*121 0 water.

II. 0*3985 grm. of the same gave 0*8320 carbonic acid and 0*] 850
water.

III. 0*3140 grm. gave 0*6565 carbonic acid and 0*1670 water.
These numbers correspond in 100 parts to —

I. II. III.

Carbon 56*97 56*94 57*02

Hydrogen 4*19 5*13 5*87

Oxygen 38*84 37*93 37*11

100*00 100*00 100*00

The great discrepancy in the amounts of hydrogen in the prece-
ding analyses arises from the circumstance that alizarine loses its
water of crystallization with such extreme facility. No. I. was mixed
with warm chromate of lead in a warm mortar ; No. II. was mixed
with warm chromate of lead in a cold mortar ; and No. III. with
cold chromate of lead in a cold mortar. In the case of No. I. there-
fore we see that the heat of the chromate of lead and the mortar
combined was sufficient to drive away more water than what corre-
sponds to 1^ per cent, of hydrogen, though this heat was not greater
than what might be borne by the hand. In order to determine the
amount of water of crystallization, crystallized alizarine was heated
in a water-bath until it lost no more in weight.

I. 0*4015 grm. treated in this way lost 0*0735 water.
II. 0*3575 grm. lost 0*0655 water.

Alizarine which had been deprived of its water of crystallization
by heat, gave, on being burnt with chromate of lead, the following
results : —

I. 0*2990 grm. gave 0*7575 carbonic acid and 0*1045 water.

II. 0*3005 grm. of a different preparation gave 0*7620 carbonic
acid and 0*1095 water.

III. 0*2765 grm. of the same preparation as the preceding gave
0*7010 carbonic acid and 0*1025 water.

In 100 parts it contains therefore —

Carbon 69*09

Hydrogen 3*88

Oxygen 27*03

100*00 100*00 100*00

II.

III.

69*15

69*14

4*04

4*11

26*81

26*75

Dr. Schunck on Colouring Matters. 211

On analysing alizarine prepared by sublimation from pure cry-
stals, I obtained the following numbers : —

I. 0*3970 grm. gave 1 0115 carbonic acid and 0'1340 water.
II. 0*4110 grm. gave 1*0510 carbonic acid and 0'1375 water.
In 100 parts —

I. II.

Carbon 69*48 69*73

Hydrogen 3*75 3*71

Oxygen 26*77 26*56

100*00 100*00

It will be seen from this that sublimed alizarine does not differ
materially in composition from alizarine which has been freed from
its water of crystallization.

Of the compounds of alizarine with bases I prepared the lime,
baryta and lead compounds. The two former were prepared by
dissolving alizarine in ammonia, and precipitating with chloride of
calcium and chloride of barium, the latter by dissolving alizarine in
alcohol and precipitating with an alcoholic solution of sugar of lead.
The latter forms a purple precipitate, which, after standing for some
hours, becomes of a dull red.

The lead compound gave on analysis the following numbers : —
T. 0*4800 grm. gave 0*2095 oxide of lead and 0*0245 metallic
lead, equivalent to 0*2359 oxide of lead.

0*5125 grm. burnt with chromate of lead gave 0*7050 carbonic
acid and 0*0780 water.

II. 0*5865 grm. of a different preparation gave 0*3970 sulphate
of lead, equivalent to 0*2920 oxide of lead.

0*6915 grm. gave 0*9370 carbonic acid and 0*1005 water.
Hence was deduced the following composition :-

Calculated
Numbers.

Found.

I. II.

14 eqs. Carbon 84 37*57 37*51 36*95

4 „ Hydrogen .. 4 1*78 1*67 1*61

3 „ Oxygen 24 10*75 11*70 11*65

1 „ Oxideof lead 111-7 49*90 49*12 40*79

223*7 100*00 100*00 100*00

The lime compound gave the following results : —
I. 0*4685 grm. gave 0*2065 sulphate of lime, equivalent to
0*0857 lime.

II. 0*4750 grm. gave 0*2125 sulphate of lime, equivalent to
0*0882 lime.

Assuming that the formula for this compound is C^ H4 03 + CaO
+ H0, its composition would be as follows : —

Calculated

Numbers. j jj

1 eq. Alizarine 112 74*91

1 „ Water 9 6*03

1 „ Lime 28*5 19*06 18*30 18*58

149*5 100*00
P2

Found.

^212 Dr. Schunck on Colouring Matters.

The baryta compound gave the following : —
0'2i50 grm. gave 0*1420 sulphate of baryta, equivalent to 0*0932
baryta.

Assuming that the formula of this compound is similar to that of
the last, viz. C,4 H4 O3 + BaO + HO, its composition would be as
follows : —

Calculated. Found.

1 eq. Alizarine 112 56*65

1 „ Water 9 4*57

1 „ Baryta 76*68 38*78 38*03

197-68 100-00

Neither of these compounds loses the equivalent of water which it
contains on being heated in a water-bath for several hours.

The composition of crystallized alizarine must therefore be as fol-
lows : —

Calculated.

14 eqs. Carbon 84 56*75

8 „ Hydrogen 8 5*40

7 „ Oxygen 56 37*85

148 100*00

or, Calculated ^°"°/*-

Numbers.

II.

1 eq. dry Alizarine. . . . 121 8176

3 eqs. Water 27 18*24 18*33 18-32

148 00*00
It follows that alizarine dried at 212° must consist of —

Calculated.

14 eqs. Carbon 84 69*42

5 „ Hydrogen 5 4*13

4 „ Oxygen 32 26*45

121 100*00

If this be the true composition of alizarine, it follows that there
exists a very singular relation between it and the composition of
benzoic acid. The formula of benzoic acid is C,4 Hg O4, and ali-
zarine only differs from it therefore by containing one equivalent less
of hydrogen. If we compare alizarine with isatine, we shall find
that the latter only differs from the former by containing in addition
the elements of one equivalent of cyanogen. The formula of isatine
is C16 H5 NO4 = C,4 H5 O4 4- C2 N. Anthranilic acid differs in
composition from alizarine in containing in addition the elements of
amidogene,for theformula of anthranilic acidisC,4H7N04=C,4 H5O4
+ NH^.

Alizar'ic Acid. — In my former report I stated that alizarine, when
treated with concentrated solutions of persalts of iron, is converted
into a new acid, which I called alizaric acid. I stated at the same

♦ See pp. 210,211.

Dr. Schunck on Colouring Matters. 213

time that I thought it probable that alizaric acid might alsobefortned
by acting on alizarine with nitric acid. This supposition has since
been confirmed. On treating pure crystallized alizarine with boiling
nitric acid, it is decomposed with an evolution of nitrous acid, and the
liquid on evaporation gives crystals of alizaric acid. It is however
not necessary to prepare pure alizarine in order to obtain alizaric
acid. 1 have found the following to be the easiest method : — Nitric
acid of about sp. gr. 1*20 having been put into a retort, garancine
is introduced into the acid, and the liquid is heated until the red
fumes have ceased to be evolved, and the colour of the garancine
has changed from dark brown to yellow. The reddish-yellow acid
liquid which is obtained, is filtered or strained to separate it from
the woody fibre, &c. of the garancine, and evaporated to crystalli-
zation. A yellow crystalline mass is obtained, which is a mixture
of oxalic acid and impure alizaric acid. After being washed with
cold water to remove the excess of nitric acid, the mass is dis-
solved in boiling water, and chalk is added until all effervescence and
acid reaction have ceased. The liquid is filtered, and the oxalate
of lime remaining on the filter is washed with boiling water, until
no more lime can be detected in the percolating liquid. The liquid
is a solution of alizarate of lime. Muriatic acid is added to it, and
it is evaporated to crystallization. A yellow mass is again obtained,
which may be washed with cold water to remove the chloride of cal-
cium, then redissolved in boiling water. It forms a yellow solu-
tion, which may be almost decolorized by animal charcoal. On
again evaporating, the alizaric acid is obtained in large crystals.
Should these crystals still retain a yellow tinge, which is generally
the case, they must be redissolved in boiling water. By passing
chlorine gas through the boiling solution, until every trace of co-
lour has disappeared, perfectly colourless crystals of the acid are
obtained on cooling. Prepared in this way, it appears in large flat
rhombic plates: it has the properties which I described in my last
report.

The salts of alizaric acid are mostly soluble. Alizarate of potash
is formed by neutralizing a watery solution of alizaric acid with
carbonate of potash : it is obtained on evaporation as a deliquescent
mass. Alizarate of lime is prepared by neutralizing alizaric acid
with carbonate of lime, and evaporating to crystallization. It crystal-
lizes in prisms, possessing great lustre. Alizarate of baryta, prepared
in the same way by means of carbonate of baryta, crystallizes in
silky needles. Alizarate of silver, prepared by double decomposi-
tion, is soluble in boiling water, from which it crystallizes on the
solution cooling. Alizarate of lead is an insoluble white powder,
obtained by precipitation of the acid with sugar of lead. With am-
monia alizaric acid does not seem to form a neutral salt. On su-
persaturating a solution of the acid with ammonia and evaporating,
the solution acquires during evaporation an acid reaction, and at
length a salt crystallizes out in flat plates, which is no doubt a super-
alizarate of ammonia. All the salts of alizaric acid, when strongly
heated, are decomposed with an evolution of a fragrant smell similar

214 Dr. Schunck on Colouring Matters.

to that of benzine, and give, as a product of the decomposition, a
thick brown oil, to which without doubt the smell is owing ; while
the carbonates of the bases, or the bases themselves, remain behind
mixed with much charcoal.

The elementary analysis of alizaric acid gave the following re-
sults : —

I. 0*5250 grm. obtained by means of perchloride of iron and
burnt with oxide of copper, gave 1"1015 carbonic acid and 0-1810
water.

II. 0-4670 grm. obtained by means of nitric acid and burnt with
chromate of lead, gave 0-9865 carbonic acid and 0-1685 water.

III. 0-4475 grm. of the same preparation as the preceding gave
0*9360 carbonic acid and 0-1625 water.

IV. 0*4395 grm., purified by means of chlorine and burnt with
chromate of lead, gave 0*9335 carbonic acid and 0-1510 water.

These numbers give in 100 parts —

I. II. III. IV.

Carbon 57*20 57-61 57*10 57*92

Hydrogen 3*83 4*00 4*03 3*81

Oxygen .... 38*97 38*39 38*87 38*27

100-00 100-00 100-00 100*00
Alizarate of lead was analysed with the following results :—

I. 0*8110 grm. gave 0*2665 oxide of lead and 0*2160 metallic
lead, equivalent to 0*4991 oxide of lead.

0*6660 grm. gave 0*5810 carbonic acid and 0*0915 water.

II. 0*6230 grm. gave 0*2040 oxide of lead and 0*1655 metallic
lead, equivalent to 0*3822 oxide of lead.

0*6515 grm. gave 0*5560 carbonic acid and 0*0860 water. Hence
was deduced the following composition : —

Calculated ^T*^*

Numbers.

I.

1
II.

14 eqs.

Carbon ....

84

23*37

23-79

23*27

4 „
2 „

Hydrogen . .
Oxygen ....
Oxide of lead

4

48

223*4

1*11
13-37
62-15

1*52
13*15
61*54

1-46
13-93
61-34

359-4 100-00 100*00 100*00

The baryta salt lost nothing in weight on being heated for several
hours in a water-bath.

I. 0*6725 grm. of baryta salt dried at 212° gave 0*5245 sulphate
of baryta, equivalent to 0*3442 baryta.

II. 0*7330 grm. gave 0*5700 sulphate of baryta, equivalent to

0-3740 baryta.

Its composition is therefore probably as follows : —

Found.

Calculated .

II.

1 eq. anhydrous Acid . 136 46-26

1 „ Water 9 2-36

2 eqs. Baryta 153*3 51*38 51*18 51-08

298*3 100*00

Dr. Schunck on Colouring Matters. 215

It is probable that the silver salt also contains two equivalents of
base to one of acid.

It follows from the analysis of the lead salt, that the hydrated acid
has the following composition : —

Calculated.

14 eqs. Carbon 84 57'92

5 „ Hydrogen 5 3*44

7 „ Oxygen _56 38-63

145 100-00

By the action of nitric acid on alizarine the latter takes up three
equivalents of oxygen without losing any hydrogen, for C14 H5 O*
+ 30 ^ Ci4 H5O7. It appears also that alizaric acid contains one
equivalent of hydrogen less, and three equivalents of oxygen more,
than benzoic acid.

Pyro-alizaric Acid. — When alizaric acid is heated it is totally vo-
latilized, and forms a sublimate in the shape of long white needles,
to which I have given the name of pyro-alizaric acid. By the action
of heat alizaric acid loses water, or the elements of water. Pyro-
alizaric acid is soluble in boiling water. The solution, however, pro-
duces exactly the same reactions as alizaric acid itself, and on eva-
poration large rhombic crystals are obtained, which have quite the
appearance of the latter acid. It is probable therefore that, by
solution in water, pyro-alizaric acid takes up again the elements of
water, and is reconverted into alizaric acid. The following results
were obtained on analysing this acid: —

I. 0-4105 grm. dried at 2 12° and burnt with chromate of lead, gave
1-0345 carbonic acid and 0-1185 water.

II. 0*4255 grm. gave 0-9985 carbonic acid and 0-1215 water.
From these numbers it may be inferred that the composition is as

follows : —

Calculated ^T^'

Numbers. Z "7?

28 eqs. Carbon 168 63'87 64-04 63-99

7 „ Hydrogen 7 2-66 2*98 3-17

1 1 „ Oxygen 88 33-47 32-98 32-84

263 100-00 100-00 100*00

Hence it follows that by the action of heat two equivalents of ali-
zaric acid lose three equivalents of water, and give one equivalent
of pyro-alizaric acid, since 2(Ci4 H5 O7) — 3HO = Cjs H^ On-

Rubiacine. — In my last report I described the method of prepa-
ration, and the properties of rubiacine and rubiacic acid, and I have
nothing further to add to what I there stated. I may mention how-
ever that I have arrived at the conclusion that rubiacine cannot be
considered as a true colouring matter, as it is impossible to dye
with it. I shall also show that, contrary to the opinion which I was
led to entertain in the first instance, rubiacine does not contribute to
produce any effect in the process of madder-dyeing.

On subjecting rubiacate of potash and rubiacic acid to analysis,
I obtained the following results : —

216 Dr. Schunck on Colouring Matters.

I. 0*4490 grin, rubiacate of potash gave 0*1090 sulphate of pot-
ash, equivalent to 0*0589 potash.

0*4350 grm. gave 0*7950 carbonic acid and 0*0900 water.

II. 0*3245 grm. gave 0*0790 sulphate of potash, equivalent to
0*0427 potash.

0*2890 grm. gave 0*5315 carbonic acid and 0*0665 water.
From these numbers it may be inferred that the salt is com-
posed as follows : —

Calculated ^«y"'i-

Numbers.

I,

^
II.

81

eqs.

, Carbon . . . ,

. 186

51*63

51*50

51*82

7

n

Hydrogen .

7

1-94

2*29

2-55

15

>>

Oxygen . .

, 120

33*31

33*09

32*47

1

11

Potash . . . ,

. 47*27

13*12

13*12

13*16

360*27 100*00 100*00 100*00

I. 0*3785 grm. rubiacic acid, dried at 212° and burnt with oxide
of copper, gave 0*7940 carbonic acid and 00845 water.

II. 0*3605 grm. of another preparation gave 0*7610 carbonic
acid and 0*0795 water.

III. 0*4670 grm. of the same preparation as the preceding gave
0*9775 carbonic acid and 0*1050 water.

Hence was deduced the following composition : —

Found.

Calculated

31 eqs. Carbon .. 186

8 ,, Hydrogen 8

16 „ Oxygen . . 128

lumbers.

f
I.

II.

III.

57*76

57*21

57-57

57-08

2*48

2*48

2*45

2*49

39-76

40*31

39-98

40*43

322 100*00 100*00 100*00 100*00
0*3150 grm. rubiacine, dried at 212° and burnt with oxide of cop-
per, gave 0'7740 carbonic acid and 0*0935 water.
This gives the following composition : —

Calculated. Found.

31 eqs. Carbon 186 67*63 67*01

9 „ Hydrogen 9 3*27 3*28

1 0 „ Oxygen , _80 29*10 29*71

275 100*00 100*00

The formula of rubiacine being C31 HgOjo, and that of rubiacic acid
CgiHgOis, it follows that when rubiacine is converted into rubiacic
acid, it loses one equivalent of hydrogen and takes up six equi-
valents of oxygen, and that when rubiacic acid is reconverted into
rubiacine, it loses six equivalents of oxygen and takes up again one
of hydrogen. This oxidation and reduction is accomplished with
the same certainty and precision as any similar process with inorganic
bodies.

Alpha-resin. — This resin is a constituent of the dark brown pre-
cipitate produced by acids in a decoction of madder. It dissolves
together with rubiacine, when this precipitate is treated with a boil-

Dr. Schunck on Colouring Matters. 217

ing solution of perchloride or pernitrate of iron, and is precipitated
together with rubiacine and rubiacic acid when muriatic acid is
added to the solution. It is separated from the rubiacine and rubi-
acic acid by means of alcohol, in which it is easily soluble, while the
two former are but little soluble. It has a dark brown or reddish-
brown colour. When cold it is brittle, and may be easily pulverized.
It begins to become soft at 150° F., and melts to dark brown drops
between 200° and 212°. When heated on platinum-foil it melts,
swells up, and burns with flame, leaving much charcoal, which how-
ever burns away without leaving any residue. When heated in a glass
tube it swells up, gives an oily sublimate, and evolves a strong smell,
leaving at last a bv.lky carbonaceous residue. It is slightly soluble
in boiling water, to which it communicates a yellow tinge. On the
solution cooling yellow flocks are deposited, which are increased in
quantity by adding an acid. It dissolves in alcohol with an orange
colour ; water makes the solution milky, and on the addition of an
acid the resin is completely precipitated in orange-coloured flocks.
The alcoholic solution does not redden litmus paper. It dissolves
in concentrated sulphuric acid with a dark orange colour, and is
reprecipitated by water in yellow flocks. It is decomposed by boil-
ing concentrated nitric acid ; on evaporating the acid a resinous mass
is left. It dissolves in caustic and carbonated alkalies with a pur-
plish red colour. The solution in ammonia does not lose its am-
monia on boiling, but on evaporation the resin is left in combination
with a little ammonia. The ammoniacal solution gives purple pre-
cipitates with the chlorides of barium and calcium, arid a dirty red
precipitate with alum. It dissolves in perchloride and pernitrate of
iron with a dark reddish-brown colour, and is re-precipitated by acids
in flocks. The alcoholic solution gives red precipitates with alco-
holic solutions of sugar of lead and acetate of copper. If chlorine
be passed through a solution of the resin in caustic potash, it is
decolorized ; acids however now produce no precipitate, so that the
resin seems to have been entirely decomposed by the chlorine.
If mordanted cloth be introduced into boiling water, in which a
quantity of the resin is suspended, the alumina mordant acquires
an orange colour, and the iron mordant a brown colour. Never-
theless these colours are so slight, that it is not likely that this resin
contributes in any way to produce the desired effect in the process
of madder-dyeing. I shall presently show that, on the contrary, it is
rather injurious than otherwise in this process, since those parts of
the cloth which should remain white acquire from it a disagreeable
yellow tinge, which cannot afterwards be removed by merely wash-
ing with water, so that even if it did contribute to produce any
greater intensity of colour on the mordanted parts, the advantage
would be more than counterbalanced by the injurious effect on the
unmordanted parts.

Beta-resin. — This resin also forms a constituent of the dark brown
precipitate produced by acids in a decoction of madder. If this
precipitate be treated with a boiling solution of perchloride or per-

218 Dr. Schunck on Colouring Matters.

nitrate of iron, the beta-resin forms a compound with peroxide of
iron, which remains undissolved. By decomposing this compound
with muriatic acid, and dissolving the resin in boiling alcohol, it is
deposited on the alcohol cooling as a light brown powder. It
hardly melts at the temperature of boiling water, but merely becomes
soft and coheres into lumps. When heated on platinum foil, it melts
and burns, leaving a slight red ash. When heated in a glass tube,
it gives yellow fumes and evolves a disagreeable smell, leaving a car-
bonaceous residue. It is slightly soluble in boiling water, to which
it communicates a yellow tinge ; on the solution cooling nothing
separates, but on adding acid some yellow flocks are deposited, while
the liquid becomes colourless. Tlie alcoholic solution is dark yel-
low ; it reddens litmus -paper. Water renders it milky, and acids
precipitate the resin completely in yellow flocks. The resin dissolves
in concentrated sulphuric acid with a dark brown colour, and is re-
precipitated by water in light brown flocks. Concentrated nitric acid
dissolves it on boiling and decomposes it; on evaporation there is
left a yellow, bitter astringent substance. It dissolves in caustic and
carbonated alkalies with a dirty red colour, inclining to purple in the
case of caustic alkali. It is re-precipitated by acids in brown flocks.
If chlorine be passed through a solution of the resin in caustic pot-
ash, it is decolorized ; but the substance itself seems to be thereby
decomposed, as acids afterwards produce only a slight precipitate.
The ammoniacal solution gives with the chlorides of barium and
calcium dirty yellow precipitates. The alcoholic solution gives with
an alcoholic solution of sugar of lead a red precipitate, and with
an alcoholic solution of acetate of copper a brown precipitate. The
ammoniacal solution loses its ammonia on evaporation, and the resin
is left as a transparent brown skin. This resin has the same effect
on mordanted cloth as the preceding ; the alumina mordant acquires
an orange, and the iron mordant a brown colour, while the un-
mordanted parts become yellow and unsightly. These effects are
not however so decided as in the case of the alpha-resin, which is
probably owing to its being less soluble in water than the latter.

Rubian. — I have given this name to the substance to which the
bitter taste of madder seems to be due. I have described its method
of preparation and properties in my last report. I may state, in
addition to what I there said, that rubian seems to be a nitrogenous
body, since, on treating it with boiling caustic alkali, ammonia is
evolved. This fact and the bitter taste seem to indicate that the
medical properties of madder, if indeed it possesses any, reside in
this substance.

If a solution of rubian in water be evaporated in contact with the
air and with the assistance of heat, it deposits a dark brown sub-
stance, which sinks to the bottom in resinous drops, so that on treat-
ing the residue after evaporation with water, it is not completely re-
dissolved ; and if the filtered liquid be again evaporated as before,
a fresh quantity of the dark brown substance is formed, just as in
the case of extractive matter. This dark brown substance melts

Dr. Schunck on Colouring Matters. 219

into drops in boiling water, but when cold it is brittle. It dissolves
in alkalies with a dark red colour, and is re-precipitated by acids
in yellow flocks ; indeed it bears in all respects a great resem-
blance to the body which I have called alpha-resin. Nevertheless
it seems to consist of more than one substance ; for if it be heated
in a glass tube over a lamp, an abundant sublimate, consisting of
shining yellow crystals, is obtained in the upper part of the tube :
these crystals very much resemble rubiacine. If it be treated with
a boiling solution of perchloride or pernitrate of iron, the liquid
becomes reddish brown, and gives after filtration a yellow precipi-
tate with muriatic acid, which is a proof of its containing either
alpha-resin or rubiacine, or both. Hence it becomes very probable
that rubiacine, the alpha-resin, and perhaps also the beta-resin, are
formed from rubian by the action of the oxygen of the air. It be-
comes still more probable when we consider the following facts : — If
an infusion of madder with cold water be allowed to stand in contact
with the air, it will be found that after some hours the liquid is filled
with a number of long hair-like crystals, which are, as I have shown
on a previous occasion*, rubiacine, generally mixed with a substance
having all the properties of beta-resin. I have had one specimen of
madder which gave such quantities of rubiacine on allowing the
infusion to stand, that it collected on the surface of the liquor as
a bright yellow scum, and by crystallizing it from alcohol it was
obtained almost in a state of purity. Now as rubiacine is insoluble
in cold water, it must in this case either have been formed from
some substance contained in the infusion by the action of the air,
or else it was at first held in solution by some other substance, such
as an alkali or alkaline earth from which it gradually became sepa-
rated, as by the formation of some acid in the liquid. I incline to
the former supposition, and think it probable that it is the rubian
which by its oxidation gives rise to the rubiacine.

Xanthine. — This substance, the method of preparing which from
a decoction of madder after the separation of the colouring matters,
&c. by acid, I have described above, is of course not a pure sub-
stance, since after ignition it leaves a considerable quantity of fixed
residue : it is also probable that it contains a small quantity of sugar,
as I stated before. Nevertheless it produces reactions of a peculiar
kind, which cannot be attributed to sugar, gum, or any similar sub-
stance, and can only be due to a peculiar body which exists only in
madder. It has the following properties : — When prepared as above
described, it is a thick, viscid, yellow or brownish-yellow syrup,
resembling honey in colour and consistency, which cannot be ren-
dered dry even by exposing it to a heat at which it begins to be de-
composed. When exposed to the air, it becomes more liquid on
account of its attracting moisture. When heated to ignition, it swells
up enormously, giving off at the same time a very perceptible smell
of aceton and burns, leaving at last a considerable quantity of ash,

* See the Report of the British Association for the Advancement of Science for
1846.

220 Dr. Schunck on Colouring Matters.

which consists of the carbonates of lime, magnesia and potash. It is
without doubt the acetates of those bases which, being mixed with
the substance, produce the smell of aceton during ignition. The
acetic acid was of course derived from the basic acetate of lead
used in the preparation of xanthine, and the acid with which they
were originally combined must have gone to the oxide of lead.
Now, as I stated above, the oxide of lead was found to be combined
with phosphoric acid ; hence it is probable that the greater part,
if not all, of the fixed bases left after the ignition of the xanthine
existed in the plant as phosphates. Xanthine has a disagreeable taste,
between bitter and sweet. The watery solution is yellow. It is
soluble in alcohol, and is left after evaporation in the same state
as before. It is insoluble in aether. On adding muriatic or sulphuric
acid to the watery solution and boiling for some time, a peculiar
smell is evolved, the solution becomes gradually dark green, and a
dark green powder is deposited. This is the most characteristic
property of xanthine. Nitric acid does not produce the same dark
green powder, or any deposit on boiling ; nevertheless the powder
which has once been formed by means of muriatic or sulphuric acid,
is not dissolved by boiling nitric acid, but only turned yellow.
Acetic acid produces no effect. Oxalic acid gives a white preci-
pitate of oxalate of lime. Bichromate of potash and sulphuric acid
produce no effect on a solution of xanthine, even on boiling. On
adding caustic potash to the solution it turns brown, and on boiling
a slight smell of ammonia is evolved. Lime and baryta water,
acetate and basic acetate of lead, the acetates of alumina, iron and
copper, nitrate of silver, corrosive sublimate, and a solution of glue,
produce no precipitate or effect whatever in a solution of xanthine.
In fact it does not seem to be precipitated by any reagent whatever
without undergoing decomposition.

a a clear light yellow watery solution of xanthine be evaporated
with the assistance of heat and in contact with the air, as on the
sand-bath, to a syrup, and this syrup be again mixed with water
and the solution again evaporated, the process being several times
repeated, the solution gradually becomes dark brown, and at length
a dark brown powder is deposited. The brown solution now gives
with acetate, or basic acetate of lead, a thick brown precipitate. The
filtered liquid is yellow, and if the excess of lead be removed by
sulphuretted hydrogen, the solution again gives, on evaporation
over sulphuric acid, a colourless or light yellow syrup, which how-
ever, if redissolved and evaporated with the assistance of heat as
before, again becomes dark brown, and deposits a dark brown pow-
der. There can therefore be no doubt that this brown powder is a
product of the oxidation of xanthine, that xanthine is a species of
extractive matter, and that the brown powder stands in the relation
to it of an apothema. This brown powder has the following pro-
perties : — When dry it is a dark brown mass, easily reduced to pow-
der. It is quite insoluble in boiling water and boiling alcohol. It
burns without flame, leaving much ash. It is soluble in concentrated

Dr. Schunck on Colouring Mailers. 22 1

sulphuric acid with a dark brown colour, and is re- precipitated by
water. Boiling dilute nitric acid decomposes it with an evolution
of nitrous acid, and changes it into a yellowish-red (locculent sub-
stance. Concentrated nitric acid on boiling decomposes and dis-
solves it entirely. It dissolves in caustic and carbonated alkalies
with a dark brown colour, and is re-precipitated by acids in light
brown flocks. The ammoniacal solution gives brown precipitates
with the chlorides of barium and calcium. The dark green powder
which is produced by the action of sulphuric and muriatic acid on
xanthine, has the following properties: — When dry it has a dark
olive colour. It burns with a flame and a smell like burning wood,
leaving a large quantity of charcoal, which however burns away
without any fixed residue. It is decomposed by boiling dilute nitric
acid, and changed into a yellow floccuient substance. It is inso-
luble in concentrated sulphuric acid, and also in boiling alcohol.
When treated with caustic potash, a part dissolves with a dark brown
colour, and is re-precipitated by acids as a dark brown powder,
while the other part remains undissolved as a black powder.

Mordanted cloth acquires no colour in a boiling solution of xan-
thine, if the latter is in its yellow unoxidized state ; but if the solu-
tion has become brown by contact with the air, then both the alu-
mina and the iron mordant acquire in the boiling solution a brown
colour, while the unmordanted parts, which should remain white,
become of a brown tint. Hence it follows that xanthine is injurious
in madder-dyeing, and must contribute, together with the two
resins, in impairing the purity of the colours, and sullying the white-
ness of those parts which should attract no colour. To get rid of
the xanthine is one object of changing madder into garancine.

It remains for me to say a few words in regard to the part which
the different substances described above play in the process of mad-
der-dyeing. I regret to say that in my last report there are con-
tained some views on this head, which I have found, on more exact
investigation, to be erroneous. The two principal points to be
determined are, which is the substance that produces the chief effect
in dyeing with madder, and why is a certain proportion of lime,
either in the plant or in the dye-bath, necessary for the production
of fine and durable colours. In my last report I stated it as my
opinion, that both alizarine and rubiacine take part in the process,
that rubiacine alone produces no effect, but that when it is in combi-
nation with an alkali or an alkaline earth, it forms double com-
pounds with the alizarine compounds of alumina and peroxide of
iron, and thus increases the intensity of colour in the latter. I have
since found that this opinion cannot be sustained, since rubiacine,
whether free or combined, produces no beneficial effect in the pro-
cess of dyeing, and is therefore no true colouring matter, as the
following experiments will show.

Since the brown precipitate produced by acids in a watery ex-

222 Dr. Schunck on Colouring Matters.

tract of madder contains all the free colouring matter of the root,
and acts in dyeing in the same way as madder itself, it was evident
that by trying the constituents of this precipitate in conjunction with
one another, both in a free state and in combination with lime, a
correct view of the part performed by each would be arrived at.
Having therefore taken a piece of calico on which three mordants
had been printed, one for red, one for purple, and one for black,
in alternate stripes, each stripe being one quarter of an inch broad,
and having intervals between them of the same width, it was divided
into pieces of six inches by three, and one of these pieces was taken
for each of the following experiments. As the tinctorial power of
alizarine is very great, so great that one quarter of a grain was
enough to over-dye one of these pieces, I took one or two grains
of crystallized alizarine, dissolved it in a measured quantity of water,
to which a little caustic alkali had been added, and was then able
to divide the solution into portions corresponding to quarters,
eighths, and sixteenths of a grain, so that by precipitating one of
these portions with muriatic acid, filtering and carefully washing,
I obtained small quantities in a state very well adapted for dyeing.
By treating one of these quantities while on the filter with lime-water,
and washing out the excess of lime, I obtained small quantities of
the lime compound of alizarine for the same purpose. The same
process was used for obtaining small quantities of rubiacine, alpha-
resin, beta-resin, peciic acid and rubian, and their lime compounds.
Each experiment was performed with the same quantity of water,
at as nearly as possible the same temperature, and occupied the same
length of time, viz. half an hour. The substances used, and their
quantities, were as follows : —

1. ^ grain of alizarine.

2. Y^g gr. alizarine.

3. Jg. gr. alizarine and -^-^ gr. alizarine in combination with lime.

4. -^^ gr. alizarine and ^^ gr. alizarine in combination with lime.

5. ^ gr. alizarine and ^ gr. rubiacine.

6. ^ gr. alizarine and ^ gr. rubiacine in combination with lime.

7. -^2 g^' alizarine and ^-^ gr. rubiacine in combination with lime.

8. ^ gr. alizarine and ^ gr. pectic acid.

9. ^ gr. alizarine and ^ gr. pectic acid in combination with lime.

10. ^ gr. alizarine and ^ gr. alpha-resin.

11. ^ gr. alizarine and ^ gr. alpha-resin in combination with lime.
\t. ^ gr. alizarine and ^ gr. beta-resin.

13. ^ gr. alizarine and ^ gr. beta-resin in combination with lime.

14. ^ gr. alizarine and ^ gr. rubian.

15. ^ gr. alizarine and ^ gr. rubian in combination with lime.

Now the following results were obtained : — No. 1 was every-
thing that could be desired in regard to all the colours. No. 2 was
of course only half as dark. No. 3 was lighter than No. 1, and the
white parts had a pink hue. No. 4 was a little darker than No. 3,
but not as dark as No. 1. No. 5 was much inferior to No. 1 ; the
red had an orange hue, the purple a reddish cast, and the black was

Dr. Schunck on Colouring Mailers. 223

brown, while the white was yellowish. No. 6 was equal to No. 1,
but not darker, and in no respect superior. No. 7 was about equal
to No. 4. No. 8 had almost no colour at all ; the red, the purple
and the black were mere tinges of colour, such as might probably
have been produced by the tenth part of the quantity of alizarine
employed, if nopectic acid had been present. No. 9 was again equal
to No. 1. No. 10 was lighter than No. 1, the purple especially being
pale and reddish, while the white parts were yellowish. No. 1 1 was
equal to No. 1, but not superior. No. 12 was exactly the same as
No. 10, the purple having a disagreeable reddish cast, while the
white parts were yellowish. No. 13 was again equal to No. 1.
No. 14 and 15 did not differ from one another, and were equal to
No. 1. Hence we may draw the following conclusions : — Alizarine
produces the greatest effect in dyeing when used alone. The ad-
dition of lime, even in very small quantities, does not increase its
tinctorial power, but on the contrary neutralizes the effect of that
portion with which it combines. Rubiacine, the alpha-resin and the
beta-resin, in a free state, when used in conjunction with alizarine,
are injurious in about the same degree : they weaken the red, the
black, and especially the purple, while they render the white part
yellowish. In combination with lime these substances do not in-
crease the tinctorial power of alizarine, they merely allow it to act
without hindrance. Pectic acid almost destroys the effect of aliza-
rine. Pectate of lime is perfectly indifferent. Rubian in a free
state, and in combination with lime, has neither a beneficial nor an
injurious effect. Of all the substances therefore contained in madder,
none is of use in dyeing but alizarine, while all the others are inju-
rious when in a free state. That which is the most hurtful is pectic
acid. When alizarine and pectic acid are present together in the
dye-bath, the pectic acid having most affinity for bases, combines
with the alumina and peroxide of iron, and the alizarine crystallizes
out when the bath cools, as I noticed in performing the experiment
No. 8. The same is without doubt the case when using rubiacine or
the resins. The alumina and peroxide of iron combine with these
substances to the exclusion of the alizarine ; and these compounds
are either colourless, or have a poor and unsightly colour. The
use of lime is therefore easily explained ; it serves, not to increase
the tinctorial power of the colouring matter, but to combine with
and render harmless the substances which are injurious in a free
state. Now if we treat madder with muriatic or sulphuric acid, we
remove all the lime and magnesia from it ; the pectic acid, the rubia-
cine and the resins become free ; and if we wash with water, the
muriatic or sulphuric acid is certainly removed ; but those sub-
stances being but little soluble in cold water, remain and destroy the
effect of the alizarine in dyeing. But if previous to dyeing we add
lime, the pectic acid, the rubiacine and the resins being more electro-
negative than alizarine, combine with the strongest base, which is the
lime; and the alizarine, which is less electro-negative, combines with
the weakest bases, viz. the alumina and peroxide of iron. If we

224- Dr, Schunck on Colouring Matters.

add an excess of lime, then of course the alizarine also combines with
the lime, and the alumina and peroxide of iron having no free body
to combine with, remain colourless. The process is thus brought
into harmony with our previous knowledge of the relative affinity
of acids and bases. It is probable that lime is not absolutely neces-
sary for the success of the operation, and that it might be replaced
by potash, soda, magnesia or baryta ; but as lime is the cheapest
substance that can be used for the purpose, it would be of no prac-
tical importance to find a substitute for it.

I have in the preceding remarks left xanthine out of consideration.
During the process of madder-dyeing this substance no doubt be-
comes oxidized, and deposits the brown substance mentioned above,
on all parts of the cloth. This substance, together with the pectic
acid, the rubiacine and the resins, are removed afterwards by passing
the cloth through a boiling solution of soap. The alkali of the soap
dissolves these substances, which have more affinity for alkalies than
alizarine, while the fat acid remains on the cloth in combination with
the alizarine, the alumina and the peroxide of iron.

In order to prove analytically that alizarine is the substance which
produces madder colours, I took several yards of cloth which had
been dyed purple with madder, but not soaped, and treated it with
muriatic acid, which removed the oxide of iron, and left an orange-
coloured substance on the cloth. After washing the cloth in cold
water until all the acid had been removed, it was treated with caustic
alkali. The brownish-red solution thus obtained was supersaturated
with an acid, and the reddish-brown precipitate formed was thrown
on a filter and well-washed with cold water : it was then treated with
boiling alcohol. The alcoholic liquid, which was dark yellow, was
spontaneously evaporated, and gave crystals of alizarine mixed with
a powder resembling beta-resin, and a few yellow micaceous plates,
which were probably rubiacine. There remained a brown residue in-
soluble in alcohol, part of which dissolved in boiling water, and
proved to be pectic acid. On treating some cloth which had been
dyed with madder, and then soaped, with muriatic acid as before, and
then with caustic alkali, I obtained a purple solution, in which acids
produced a yellow precipitate. This precipitate was treated with
boiling alcohol like the other ; it gave a yellow liquid, which on eva-
poration afforded crystals of alizarine, together with white masses of
fat acid. Hardly any residue remained undissolved by the alcohol.

The preceding observations have a great bearing on the manufac-
ture and treatment of garancine. Garancine is the technical name for
a preparation of madder, which is obtained by treating madder with
hot sulphuric acid until it has acquired a dark brown colour, then
adding water, straining and washing until all the acid is removed.
The advantages which garancine has over madder are, that it dyes
finer colours, that the part destined to remain white does not acquire
any brown or yellow tinge, and that its tinctorial power is greater
than that of the madder from which it has been prepared. These
effects have been attributed to various causes. It has been asserted

Notices respectiiig New Books, 225

that the sulphuric acid destroys the gum, the mucilage, the sugar,
&c., and leaves the colouring matter unaffected ; hence the greater
beauty of garancine colours. To account for the greater proportional
effect of garancine, it has been said that a part of the colouring mat-
ter is enclosed in cells of the wood, so that it cannot be dissolved by
water, and that the sulphuric acid destroys the wood and liberates
the colouring matter. To these views it may be objected, that con-
centrated sulphuric acid, though it does not affect alizarine, does not
destroy any of the injurious substances in the root except the xan-
thine, while the rubiacine, the resins, and the pectic acid, escape
its action : and as far as the wood is concerned, I can affirm that
the operation succeeds equally well if acid be taken of such dilution
as not to destroy woody fibre. I think that the superiority of garan-
cine can only be attributed to two causes. In the first place, since,
as I have shown above, there is a quantity of colouring matter in
the root combined with lime and magnesia, by which it is rendered
insoluble and incapable of dyeing, one effectof the acidis to remove
this lime and magnesia, and to set the alizarine at liberty, which is
then capable of application. In the second place, the xanthine,
which has an injurious effect in madder-dyeing, is removed by
washing with cold water, since it is not precipitated by acids, while
the whole of the alizarine remains. If hot acid is employed, then
the xanthine, or a part of it, is converted into that dark green sub-
stance which I have mentioned above as the product of the action
of muriatic and sulphuric acid on xanthine ; hence the dark colour of
garancine, which is not owing to the charring of the woody fibre, as
sometimes asserted. It must be remembered however that the ru-
biacine, the resins and tTie pectic acid, as well as the alizarine, remain
uncombined after treatment with acid. Hence it becomes necessary
to add some base with which these substances may combine, so as
not to interfere with the action of the alizarine. I believe it is the
practice of garancine manufacturers to employ soda for this purpose.
I think it would be better to use a small quantity of lime-water.

I may state in conclusion that the experiments described in this
and the last report were made with Avignon madder. The con-
stituents and properties of Dutch madder, which is of rather a dif-
ferent nature, remain to be examined.

I have been lately engaged in examining the colouring matter of
fustic, which I have prepared in a state of purity, but the investiga-
tion is not sufficiently advanced to justify me in making known the
results on the present occasion.

XXIX. Notices respecting New Books.

Introduction to Meteorology. By David Purdie Thompson, M.D.
Blackwood and Sons.

n|"'HERE is no branch of physical science which has made so little
-■• progress, and of whose laws our knowledge is so limited, as
that of Meteorology. Hence every encouragement should be given
Phil. Mag. S. 3. Vol. 35. No. 235. Sept. 184.9. Q

226 Notices respecting New Books,

to every undertaking which endeavours to increase our knowledge
of meteorological science, either by improving instruments themselves,
their positions in observations, accuracy in observing, or the devotion
of the great labour necessary for their reduction to useful results, or
by elementary publications aiming at precision on all these points.

Meteorology has been greatly slighted. By the term Meteorology
we do not mean the mere raw observations of phsenomena, but the
systematic observations of different subjects of research, their com-
plete reduction and combination with simultaneous observations,
and, as far as possible, the deduction of mathematical formulae which
will represent the results of the observations. It must be confessed
that there have been many meteorological journals kept by ardent
observers, and that some of them have extended over long periods of
time ; yet there has been a total want of combination of observations
taken simultaneously at different places. The few results, therefore,
which have been published from the various journals, bear the stamp
of local influence. Each observer has confined his attention to his own
observations ; which, if conducted in the best possible way and with
the best possible instruments, must exhibit the peculiarities of the
place of observation, but to an unknown amount.

Within the last few years an attempt has been made to remove
these evils. The estabhshment of various observatories in the colonies,
that at the Royal Observatory, Greenwich, that at Makerstoun, near
Edinburgh, by Sir Thomas Brisbane, and more recently the organi-
zation of many observers in England by Mr. Glaisher, the results
being published quarterly by the Registrar-general, are important
steps in the right direction.

Such is the present state of meteorology, that facts are to be
assembled as observed, and principles established as soon as possible.
We could wish to see the present system greatly extended ; the im-
portant results which we then might fairly expect would be of the
utmost value in various ways.

The following abstract of the work by Dr. Thompson may perhaps
assist our readers to judge of the additions made by it to our present
knowledge of meteorological literature and science.

It opens with an introductory sketch of meteorology, and treats
of the ancient superstitions respecting meteorological phaenomena,
and the supposed power of the ancients in controlling such.

In the Jlrst chapter are explained the opinions of the ancients upon
the atmosphere, and the advance of our knowledge regarding it to
the present time. This leads to a discussion upon chemistry, and
the connexion of chemical and atmospherical phaenomena ; the figure
of the atmosphere, its density ; the different temperatures at which
water boils at different elevations ; effects of elevation upon respira-
tion ; variations in the reading of the barometer, with many anec-
dotes, and a curve showing the mean monthly reading of the baro-
meter at Greenwich, deduced from the observations taken there
during the years 1841-1845, fill the second chapter.

The third chapter opens with an interesting extract from Ossian,
and treats upon the sun and the solar beams, upon temperature in

Notices respecting New Books. 227

general, particularizing the hours whose temperature agrees with
that of the mean for diiferent places.

The fourth traces the direction of isothermal lines ; speaks of the
mean annual temperature at various places ; and gives a curve of the
mean monthly temperature at Greenwich, deduced from the obser-
vations taken at the Royal Observatory in the years 1841, 1842,
1843 and 1844, but which curve differs from the numbers at the
foot of the diagram. The numbers are correct. In this chapter
the effects of heat and cold are treated, and many interesting anec-
dotes are mentioned.

The fifth speaks of the colour of the atmosphere, of refraction,
twilight, polarization of light, &c.

The sixth treats of evaporation and vaporization.
The seventh treats of dew and radiation of heat, particularizing the
experiments of Dr. Wells, but mentions no subsequent English ex-
periments ; of mists, fogs and clouds.

The eighth is employed upon rain, in considerable detail. The
ninth is devoted to the consideration of hail, snow, glaciers, &c. The
tenth to the rainbow, and to all the phsenomena connected with the
cirrostratus cloud. The mirage is the principal subject of the eleventh,
and lightning that of the twelfth. The thirteenth chapter relates to
meteors in general. The fourteenth to the aurora borealis and to
magnetism. The fifteenth treats of the direction and strength of
the wind. The sixteenth is occupied by particulars respecting the
simoom and the sirocco ; the seventeenth by whirlwinds, great storms
and hurricanes ; and the eighteenth by popular prognostications of
the weather.

In each chapter a great number of instances of the class of phseno-
mena is collected. Such are the parts of this work ; and we cannot
doubt that the public will receive it with favour. It is amusing ;
there are many interesting anecdotes interspersed ; it is written in a
pleasing style ; and great taste has been exhibited in the aptness and
beauty of some of the poetic quotations.

The chapter on instruments, which appears as an appendix, is the
least interesting and satisfactory portion of Dr. Thompson's work.

The account given of the barometer is merely popular ; and the
sketches given of this instrument do not include that of a standard.
A large space is devoted to the aneroid barometer ; which, beautiful
as it is for domestic and ordinary purposes, is totally unfitted for
meteorological or experimental inquiry. Dr. Thompson gives the
impression that the aneroid barometer is as accurate in its indications
as a perfect mercurial barometer ; in fact, says that the mean differ-
ence of the readings of the two, from 109 simultaneous comparisons,
is only two-thousandths of an inch, this result being deduced from
the observations published by Mr. Dent on the aneroid barometer.
But Mr. Dent in his pamphlet only asserts that the comparisons
were made with two of the most expensive and perfect mercurial
barometers ; neither of which is described or again mentioned. The
readings by these barometers do not seem to have been corrected for
temperature ; so that the near agreement of the readings only indi-

Q2

228 Cambridge Philosophical Society.

cates that the correction for temperature of this particular aneroid
was nearly of the same amount as that of the mercurial barometer,
even supposing it to be free of index-error. In the second table of
Mr. Dent, the readings of a maximum and minimum thermometer
are given, neither of which were probably true at the time the ob-
servation was taken.

The sympiesometer is fully described, an instrument that is not
used in meteorological investigations ; whilst the dry and wet bulb
thermometers are not described at all, which are in use in every ob-
servatory.

The rain-gauge figured in the book is one with a float and staff,
of the worst possible form ; and if made as sketched in the book,
would give erroneous results, particularly when the wide staff was
high, and thereby increasing to- a considerable extent the receiving
surface of the gauge.

No mention whatever is made about the necessity of having good
instruments, and such that have been compared with standards before
use. No instructions are given as to the making of observations, or of
the method of recording them ; and yet in any work bearing the title
of an Introduction to Meteorology, these ought surely to be given,
and particularly when one chapter is devoted to instruments. The
work should more properly be called, a Treatise upon Meteorological
Phsenomena ; and even in this particular it is incomplete. Although
a multitude of facts are collected and detailed, and some of a recent
date, no mention whatever has been made of the fine series of
results derived from the Makerstoun observations by Sir Thomas
Brisbane, and published in the Transactions of the Royal Society of
Edinburgh ; neither of any of the meteorological papers of results
published in the Philosophical Transactions for several years past ;
and the references to the Greenwich volumes are very few, and none
since the volume for 1844.

We shall conclude with one remark only. Dr. Thompson in his
concluding paragraph says, that the instruments of which he has
spoken are the chief instruments used by meteorologists. In our
most active meteorological observatories not half the instruments here
described are used at all ; and the instruments actually required are
few in number : these should be good ; and before use, should pass
through the hands of a gentleman accustomed to them. In fact the
general laws which govern atmospheric phsenomena can be found
only by accurate deductions from the observations of such instru-
ments.

XXX. Proceedings of Learned Societies.

CAMBRIDGE PHILOSOPHICAL SOCIETY.
[Continued from vol. xxxiv. p. 458.]
April 23, ^^N the Variation of Gravity at the Surface of the
1849. ^ Earth. By G. G. Stokes, M.A., Fellow of Pem-
broke College, Cambridge.

In the theory of the figure of the earth on the hypothesis of ori-

Cambridge Philosophical Society. 229

ginal fluidity, a simple exiJression is obtained for the variation of
gravity along the surface, which contains the numerical relation
between the ellipticity and the ratio of polar to equatoreal gravity,
known as Clairaut's theorem. The demonstration, however, of this
expression does not require the hypothesis of original fluidity, if the
spheroidal form of the surface and its perpendicularity to the direction
of gravity be assumed as results of observation. On the hypothesis
merely that the earth consists of nearly spherical strata of equal
density, Laplace has established a connexion between the form of
the surface, regarded as a surface of equilibrium, and the variation
of gravity along it ; and in the particular case in which the surface
is an oblate spheroid of small ellipticity, having its axis of figure
coincident with the axis of rotation, the expression which results for
the variation of gravity is identical with that which is obtained on
the hypothesis of original fluidity. The object of the author in the
first part of this paper is to obtain the general connexion between
the form of the surface and the variation of gravity along it, by an
application of the doctrine of potentials, without making any hypo-
thesis whatsoever respecting the distribution of matter in the interior
of the earth.

The latter part of the paper was devoted to the consideration of
the irregularities produced in the variation of gravity by the irregular
distribution of land and sea at the surface of the earth. The author
has shown why gravity should appear less on continents than on
small islands situated at a distance from any continent, which is a
circumstance that has long since been observed. The result is ac-
counted for by the elevation of the sea-level produced by the attrac-
tion of a continent, in consequence of which a station on a continent
is further removed from the centre of the earth than it appears to be.
It is shown also that the numerical value of the earth's ellipticity,
which has been deduced from pendulum experiments, is somewhat
too great, in consequence of the undue proportion of oceanic stations
in low latitudes, among the group of stations at which the observa-
tions were made which have been employed in the discussion.

The author has given formulae whereby observed gravity may be
corrected for the irregularities of the earth's surface. These formulae
require a knowledge, or at least an approximate knowledge, of the
height of the land and the depth of the sea throughout the earth's
surface. The sign and magnitude of the diff^erence between observed
gravity, and gravity calculated on the hypothesis of the earth's ori-
ginal fluidity, appears on the whole to depend on the insular or con-
tinental character of the station at which the observation has been
taken. This circumstance renders it probable, that if observed gra-
vity were corrected for the irregular attraction due to the irregular
distribution of sea and land throughout the whole surface of the
earth, the result would agree far better with gravity calculated on
the hypothesis of original fluidity.

May 7. — Additional Note to a Memoir on the Intrinsic Equa-
tion of Curves, By Dr, Whewell.

This note contained an extension of a theorem discovered by John

230 Cambridge Philosophical Society.

Bernouilli, and demonstrated by Euler, to this effect : that if from
any rectangular curve a string be unwrapped, and from the curve so
described again a string unwrapped, and so on perpetually and alter-
nately in opposite directions, the curves constantly tend to the form
of the common cycloid. The extension is to this effect : that if the
original curve be not rectangular, the curves perpetually tend to the
form of an epicycloid or hypocycloid, according as the angle is greater
or less than a right angle.

May 21. — Discussion of a Differential Equation relating to the
breaking of Railway Bridges. By G. G. Stokes, M.A., Fellow of
Pembroke College.

In August 1847 a Royal Commission was appointed •" for the
purpose of inquiring into the conditions to be observed by engineers
in the application of iron in structures exposed to violent concussions
and vibration." Among other branches of inquiry, the members of
the Commission have lately been making experiments on the motion
of a carriage, variously loaded in different experiments, which passed
with different velocities over a slight iron bridge ; the object of the
experiments being to examine the effect of the velocity of a train in
increasing or decreasing the tendency of a bridge over which the
train is passing to break under its weight. The remarkable result
was obtained, that the deflection is in some cases much greater than
the central statical deflection, and that the greatest deflection takes
place after the body has passed the centre of the bridge. In in-
vestigating the theory of the motion, reducing the problem to the
utmost degree of simplicity by regarding the moving carriage as a
heavy particle, and neglecting the inertia of the bridge, Professor
Willis, who is a member of the Commission, was led to a differentieil
equation of the form

d^y by

dx^~^ {2cx—x^y

where x, y are the horizontal and vertical co-ordinates of the moving
body, 2c is the length of the bridge, and a, b are certain constants.
Professor Willis requested the author's consideration of this equation,
with a view to obtain numerical results, and to determine, if possible,
the velocity which produces a maximum deflection.

The author has expressed y in a series according to ascending
powers of x, which is convergent when x < 2e. The convergency,
however, becomes very slow when x approaches the limit 2c ; and
the series does not point out the law according to which f{x) or y
approaches its extreme value 0 as a? approaches 1c. When the con-
stant term in the second member of the preceding equation is omit-
ted, the equation may be integrated in finite terms ; and consequently
the variables can be separated in the actual equation, so thaty(a:)
can be expressed explicitly by means of definite integrals. In this
way the author has obtained y(2c — x)—f{x) in finite terms, so that
the numerical value of /(a?) may readily be obtained from a?=c to
it;=2c, after it has been calculated from the series from x=^0 to a;=c :
and between these limits the series is very convergent, being ulti-

Hoy al Society, 231

mately a geometric series with a ratio — -. The author has also in-

vestigated a series proceeding according to ascending powers of c— ar,
which converges more rapidly than the former when x approaches c.
By the use of these two series, /(a;) may be calculated by means of
series which are ultimately geometric series, with ratios ranging
from 0 to ^.

The unsymmetrical form of the trajectory, and the largeness of
the deflection produced by the moving body, come out from the in-
vestigation. I3y means of the numerical values of f{x) the author
has drawn a figure representing the trajectory for four different ve-
locities. The expression for the central deflection, however, becomes
infinite when x becomes equal to 2e, which shows that it is neces-
sary to take into account the inertia of the bridge ; although, if the
bridge be really light, the solution obtained when the inertia of the
bridge is neglected may be sufficiently exact for the greater part of
the body's course.

ROYAL SOCIETY.

[Continued from p. 154.]

June 14, IS^Q. — The President announced, that in accordance
with the resolution of the Society, requesting him to communicate
the thanks of the Society to the Government of the United States
for the steps taken by them to ascertain the fate of the Expedition
under Sir John Franklin, he had addressed the following letter to
His Excellency the American minister: —

My dear Sir, 3 Connaught Place, June 8, 1849.

I have the honour to inform you that at the annual meeting of
the Royal Society, held the 7th inst., a communication was read
from Admiral Sir Francis Beaufort, in which he ajiprised the So-
ciety that the American Government had nobly undertaken to send
an expedition in search of Sir John Franklin. Upon which a vote
of thanks was moved by Sir Charles Lemon, seconded by Lord
Northampton, and carried with the utmost enthusiasm, expressive
of the gratitude of the Royal Society to the American Government,
and of their deep sense of the kind and brotherly feeling which had
prompted so liberal an act of humanity. Allow me to assure you,
that it is peculiarly gratifying to me to have the honour of being
the humble instrument in conveying to you the thanks of the Royal
Society on this occasion, and permit me to express a hope that this
most generous act of the United States may, if possible, draw closer
the bonds of friendship between the two kindred nations.

That the United States may continue to progress with the same ex-
traordinary rapidity in the arts of peace and civilization, and to hold

23-2 Royal Society.

tlie same high place in the science and literature of the world, is I
ara sure the anxious desire of the Royal Society.

I have the honour to be,
My dear Sir,
Your most obedient humble Servant,

RossE, P.R.S.

" On Carbonate of Lime as an ingredient of Sea-water." By
John Davy, M.D., F.R.S. Lond. & Ed., Inspector-General of Army
Hospitals, &c.

The manner in which limestone cliffs rising above deep water are
worn by the action of the sea, as it were by a weak acid, such as we
know it contains, viz. the carbonic — the manner, further, in which
the sand on low shores where the waves break, becomes consolidated,
converted into sandstone, by the deposition of carbonate of lime
from sea- water owing to the escape of carbonic acid gas, — are facts
clearly proving that carbonate of lime is as a constituent of sea- water
neither rare of occurrence, nor unimportant in the ceconomy of na-
ture, inasmuch as the phaenomena alluded to, — the one destructive,
the other restorative, — have been observed in most parts of our
globe where geological inquiry has been instituted.

Reflecting on the subject, it seemed to me desirable to ascertain
whether carbonate of lime as an ingredient of sea-water is chiefly
confined to the proximity of coasts, or not so limited enters into
the composition of the ocean in its widest expanse.

On a voyage from Barbados in the West Indies to England in
November last (1848), I availed myself of the opportunity to make
some trials to endeavour to determine this, the results of which I
shall now briefly relate.

First, I may mention that water from Carlisle Bay in Barbados,
tested for carbonate of lime, gave strong indications of its presence ;
thus a well-marked piecipitate was produced by ammonia, after the
addition of muriate of ammonia in excess, that is, more than was
suflficient to prevent the separation of the magnesia which enters so
largely into the composition of sea-water ; and a like eff'ect was pro-
duced either by boiling the water so as to expel the carbonic acid,
or by evaporation to dryness and resolution of the soluble salts.

On the voyage across the Atlantic, the test by means of ammonia
and muriate of ammonia was employed, acting on about a pint of
water taken from the surface. The first trial was made on the 15th
of November, when in latitude 20° 30' N., and longitude 63° 20' W.,
more than a hundred miles from any land ; the result was negative.
Further trials were made on the 22nd of the same month in lat.
32° 53', long. 45° 10' ; on the 24th, in lat. 36° 23', long. 37° 21' ; on
the 25th, in lat. 37° 21', long. 33° 34'; on the 26th, in lat. 38° 28',
long. 30° 2' ; on the 27th, when off Funchal of the Western Islands, in
lat. 38° 32', long. 28° 40', about a mile and a half from the shore, the
water deep blue,as it always is out of soundings: in all these instances
likewise the results were negative; the transparency of the water
was nowise impaired by the test applied. The last trial was made on

Royal Society. 233

the 3rd of December, when in the Channel oHPortland Head, about
fifteen miles ; now, slight traces of carbonate of lime were obtained,
a just perceptible turbidness being produced.

The sea-water from Carlisle Bay, the shore of which and the ad-
joining coast are calcareous, yielded about 1 per 10,000 of carbonate
of lime, after evaporation of the water to dryness, and the resolution
of the saline matter. A specimen of water taken up on the voyage
off the volcanic island of Fayal, about a mile from land, yielded a
residue which consisted chiefly of sulphate of lime, with a very little
carbonate of lime, — a mere trace ; acted on by an acid it gave off
only a very few minute air-bubbles. A specimen taken up off Port-
land Head, about fifteen miles, yielded on evaporation and resolu-
tion of the saline matter only a very minute residue, about '4 only
per 1 0,000; it consisted in part of carbonate and in part of sulphate
of lime.

What may be inferred from these results ? Do they not tend to
prove that carbonate of lime, except in very minute proportion, does
not belong to water of the ocean at any great distance from land ?
And, further, do they not favour the inference, that when in nota-
ble proportion, it is in consequence of proximity to land, and of
land, the shores of which are formed chiefly of calcareous rock ? In
using the word proximity, I would not limit the distance implied to
a few miles, but rather to fifty or a hundred, as I am acquainted
with shores consisting of volcanic islands in the Caribbean sea de-
stitute of calcareous rock, on which, in certain situations, sandstone
is now forming by the deposition from sea-water of carbonate of lime.

Should these inferences be confirmed by more extensive inquiry,
they will harmonize well with the facts first referred to, the solvent
power, on one hand, of sea-water impregni»ted with carbonic acid
on cliffs of calcareous rock in situations not favourable to the dis-
engagement of carbonic acid gas ; and the deposition, on the other
hand, of carbonate of lime to perform the part of a cement on sand,
converting it into sandstone, in warm shallows, where the waves
break under circumstances, such as these are, favourable to the dis-
engagement of this gas ; and, I hardly need add, that the same in-
ferences will accord well with what may be supposed to be the re-
quirements of organization, in the instances of all those living things
inhabiting the sea, into the hard parts of which carbonate of lime
enters as an element.

Apart from the oeconomy of nature, the subject under considera-
tion is not without interest in another relation, — I allude to steam
navigation. The boilers of sea-going steam-vessels are liable to
suffer from an incrustation of solid matter firmly adhering and with
difficulty detached, liable to be formed on their inside, owing to a
deposition which takes place from the salt water used for the pro-
duction of steam. On one occasion that I examined a portion of
such an incrustation taken from the boiler of the " Conway," a ves-
sel belonging to the West Indian Steam Packet Company, I found
it to consist principally of sulphate of lime, and to contain a small

234< Royal Society.

proportion only of carbonate of lime. This vessel had been em-
ployed previously in transatlantic voyages, and also in intercolonial
ones, plying between Bermudas and the Island of St. Thomas, and
in the Caribbean sea and the Gulf of Mexico.

The composition of this incrustation, like the preceding results,
^ould seem to denote, if any satisfactory inference may be drawn
from it, that carbonate of lime is in small proportion in deep water
distant from land, and that sulphate of lime is commonly more
abundant. The results of a few trials I have made, whilst rather
confirmatory of this conclusion, showed marked differences as to the
proportion of sulphate of lime in sea-water in different situations.
That from Carlisle Bay was found to contain 11*3 per 10,000. A
specimen taken up in lat. 29° 19' and long. 50° 45', yielded about
2 per 10,000, with a trace of carbonate of lime. A specimen taken
up off Fayal yielded about 9 per 10,000, also with a trace of car-
bonate of lime. One taken up off Portland Head, about fifteen miles
distant, yielded, as already remarked, only "^ per 10,00*0, part of
which was sulphate, part carbonate of lime.

By certain management, I am informed, as by not allowing the
sea-water in the boilers to be concentrated beyond a certain degree,
the incrustation, in the instances of the transatlantic steamers, is in a
great measure prevented. Perhaps it might be prevented altogether,
were sea- water never used but with this precaution, and taken up at
a good distance from land, and in situations where it is known that
the proportion of sulphate of lime is small. If this suggestion be of
any worth, further, more extensive and exact inquiry will be re-
quisite to determine the proportion of sulphate of lime in different
parts of the ocean, and more especially towards land. By the aid of
the transatlantic steam navigation companies means for such an in-
quiry may easily be obtained ; and it can hardly be doubted that
the results will amply repay any cost or trouble incurred.

Lesketh How, Ambleside,
March 29, 1849.

" On the Universal Law of Attraction, including that of Gra-
vitation, as a particular case of approximation deducible from the
principle that equal and similar particles of matter move similarly
relatively to each other." By John Kinnersley Smythies, Esq. Com-
municated by T. F. Ellis, Esq., F.R.S.

After stating the general object of his investigations and explain-
ing the notation he employs, the author enters upon some prelimi-
nary geometrical inquiries. He gives the equation between the six
right lines drawn between four points in a plane ; the solidity of a
tetrahedron in terms of its edges : the equation between the cosines
of the six angles made by four right lines meeting in a point ; and
the equation between ten right lines drawn between five points, with
some formulee of verification. Giving some general rules for the
transformation and consolidation of series, he transforms the last
equation into one involving the solidities of tetrahedrons, and shows
how the sign of each tetrahedron in that equation is determined by

Royal Society. 235

its position relatively to the least solid including them all ; and then
gives the equation between all the right lines drawn between n
points.

Having shown that the result of differentiating the product of n
variables, m times successively may be derived from the mth power
of the sum of the n variables, developed by the polynomial theorem
by substituting for every power of each variable its differential of an
order numerically the same as the power ; and applied the theorem
to find the differential of the mth order of the equation between ten
right lines drawn between five points ; the author gives the first four
successive differentials of the same equation in another form.

Proceeding with his investigation he deduces thfe necessary equa-
tion between the distances and central forces of five moving points,
and derives from it the general system of equations which determine
the motion of any number of spheres in terms of <p (the function of
the distance according to which the attractive force varies), their
masses and mutual distances. After proving that any number of
spheres may move so that the central force shall vary directly as the
distance, he shows that only certain values of <p are possible for an
infinite number of spheres, giving the criterion of possibility ; and
thence that the only possible law of central force for an infinite
number of spheres is that in which the force varies directly as the
distance.

The author then enters upon some general considerations on the
physical impossibility of an universal law, rigorously exact and ex-
pressed by equations involving differentials of no higher order than
the second, and on the amount of disturbance by extraneous agen-
cies. Having shown how all equations expressed by rectangular
coordinates may be transformed into others involving only the mu-
tual distances of the spheres at m equal intervals of time, he gives
an equation of diflFerences defining the motion of n points, such that
the distances and their differentials of every order not exceeding m
may have any assigned values.

After deducing a general formula for transforming equations of
differences not exceeding the mth order into equations between the
distances at m equal intervals of time, the author applies it to the
last equation, and shows that the equations so found are possible for
any number of moving points and for every value of m ; and that
the most general law, by which the motion of n equal spheres can
be determined, so that all move according to the same law at all
times, may be found by taking a proper value of m. He then shows
that these equations give a method of unlimited approximation to
any unknown law ; and suggests the mode of extending the solution
of the problem to solids of any figure and mass. Finally, he gives
the mth differential of the distance between any pair of points mo-
ving according to this law, in terms of the differentials of lower
orders including the distances.

[ 236 ]

XXXI. Intelligence and Miscellaneous Articles.

EXPERIMENTS ON THE NITROGENOUS COMPOUNDS OF THE
BENZOIC SERIES. BY G. CHANCEL.

THESE experiments relate principally to the action of the hy-
drosulphate of ammonia upon nitrobenzamide. This substance
was first obtained by Mi-. Field by the action of heat upon the nitro-
benzoate of ammonia ; but this process does not always succeed,
and I have found it most advantageous to prepare it from nitro-
benzoic aether and ammonia.

The action of the hydrosulphate of ammonia upon nitrobenzamide
dissolved in alcohol is frequently very complex, whilst with an
aqueous solution it is very simple ; in the latter case there is a con-
siderable deposit of sulphur and of crystals, which according to my
analyses contain C^ H^ N^ O + aq. The water of crystallization is
expelled between 212° and 248°.

The formation of this body is in conformity with the known reac-
tions of the hydrosulphate of ammonia upon nitrogenized sub-
stances; we have, in fact, C7H'5XNO + 3SH2= C7H8N2 0+ 20H2
+ 3S* ; but if the formation of this substance comes within the
known reactions, the change of functions which has taken place is
hitherto without example in organic chemistry ; for it no longer be-
longs to the benzoic series, but represents carbanilamide or anilamic
urea, that is to say a double carbonate of aniline and ammonia less
2 equivs. water (CH^ O^, C^ H? N, NH^) - 20H'^ = C^ H^ N^ O.
This opinion is founded upon the following facts : — When carbani-
lamide is heated with potash-lime, ammonia is disengaged at a
slightly elevated temperature, which I determined in the state of the
platinochloride. When heated still more strongly, no more ammonia
is given off, but only pure aniline. The following equation will
explain this metamorphosis : —

C^ Hs NO-f 20KH=C03 K2 + C« H? N-f-NH^.

But this equation evidently does not represent the final reaction,
and we must distinguish two phases, in

The first, C' H^ NO + OKH = NH^ -|- C He KNO^.
The second, O W KNO^-f 0KH=C6 H7 NCO^ K*.

The salt of potash which is produced in the first phase must be
the anthranilate or an isomeric compound, in all cases the true car-
banilate.

This experiment proves that carbanilamide contains the consti-

* X=N02 C=12 H = l 0=16 N = 14, notation of M. Gerhardt.

Intelligence and Miscellaneous Articles. 237

tuents of 1 equiv. ammonia and of 1 equiv. aniline. The action of
sulphuric acid is equally distinct, and supports my opinion ; it fur-
nishes, in fact, sulphanilic acid and sulphate of ammonia, with disen-
gagement of carbonic gas : —

O H8 NO-I-2S04 H2=CO«-|-C6 H^ NSQa-HSO* HS NH^.

By acting with cyanic acid upon aniline, M. Hofmann obtained
a substance to which he likewise assigns the composition of anilamic
urea. As this chemist has merely announced the production of this
substance vvithout describing its properties, I am not able to assert
their identity.

Carbanilamide possesses the following properties : — It is soluble
in water, alcohol and aether: its alcoholic or aethereal solution
quickly acquires a dark red colour, and appears to experience some
change, but its aqueous solution is not altered, and furnishes on
spontaneous evaporation very beautiful, transparent, flattened prisms
of considerable size. The crystals have no odour ; they have a cool,
very slightly bitter taste, similar to nitre ; they contain 1 equiv.
water of crystallization, melt at 161°, and are decomposed at a
higher temperature, leaving a large amount of carbon.

Carbanilamide, like urea, combines with acids and metallic salts,
furnishing crystalline compounds. I have analysed the following : —

The nitrate C^ H^ N^ O, NO^ H

The argentonitrate C H^ N^ O, NO^ Ag

The chloride. C^ Hs N^ O, CIH

I likewise obtained the hydrargyrochloride and the platinochloride.
In concluding this extract, I may state that I have also analysed
the aethers of nitrobenzoic acid ; that from alcohol crystallizes
in right rhombic prisms of 122"; my analyses confirm those of
M. Kopp ; that from pyroligneous aether crystallizes in nearly the
same form (118° to 120°) ; the two aethers are consequently isomor-
phous. — Comptes Rendus, Feb. 26, 1849.

ON THE COMPOSITION OF STEARIC ACID.
BY MM. LAURENT AND GERHARDT.

According to the most recent analyses which have been made in
Germany by the process generally in use, and under the direction
of M. Liebig, the composition of stearic and margaric acids came
to the support of the theory of organic radicals, by assigning to
the-<e acids formulae similar to those of hyposulphuric and sulphuric
acids. In a word, these two acids, supposed in the anhydrous state,
presented two different stages of oxidation of the same radical,

238 Intelligence and Miscellaneous Articles.

Tl* O* and RO^, R expressing the composition of a hypothetical
radical, margaryle, C^* H'^^*.

On taking into consideration the great analogy of the physical
characters of these two acids and the perfect identity of their che-
mical properties, that is to say of their metamorphoses under the
influence of reagents, we were led to doubt the accuracy of the for-
mulae which established between them so great a difference. On
the other hand, the formula attributed to stearic acid was in contra-
diction to the propositions we have advanced respecting the divi-
sibility of the formulae of organic substances. Either these propo-
sitions were false or the composition of stearic acid adopted by
the Giessen school was inaccurate. Experiment could alone decide
this. Now we have found, in the first place, that stearic land mar-
garic acids have the same atomic weight; on this point we agree
with all those chemists who have analysed the salts. We have made
seven analyses of stearic acid, derived from four different sources.
The differences between the analyses amount for the carbon to one
or two-thousandths, and scarcely to one-thousandth for the hydrogen.
They lead exactly to the formula of margaric acid, viz. C^* H'^s O*.
We have likewise observed, as was announced by M. Chevreul long
since, that pure stearic acid may be distilled for the greater part
without alteration, and that it behaves in this respect like all the
other volatile acids of the same homologous series, as formic, acetic,
butyric acids, &c. If, under certain circumstances, this distillation
is accompanied by the formation of other products, for instance
liquid hydrocarbons, they may be entirely avoided by distilling from
15 to 20 grms. of the pure acid, and interrupting the operation as
soon as the last portions acquire a faint brownish tint. Again, if
some German chemists have observed in the distilled acid a lower
melting-point, which led them to view the product as margaric acid ;
this decomposition, if it occurs, is effected, according to us, without
any decomposition, and can only be the result of some molecular
change.

In fact, a greater difference does not exist between stearic and
margaric acid than between tartaric and metatartaric acid ; they are
two physical varieties of one and the same chemical species ; mar-
garic acid should be called metastearic acid.

This result is moreover confirmed by all the reactions known of
these bodies; the identit}' of composition and of characters of the
substances described by M. Bussy under the names of margarone
and stearone; the identity of the results obtained by M. Erdmann
in the analyses of the products of anhydrous phosphoric acid upon
stearic and margaric acids ; lastly, the identity of the atomic weights
of these two acids — all these facts now find their natural explanation
in this state of isomerism which we have pointed out.

The chemical history of the fatty substances is thus simplified.

* Margaric acid, C^^Hbso^+H^O ; stearic acid, 2(C3< H'^^) 05-f-2H2 0 (bibasic)
_Q68 H'-'^O^, with the oxygen indivisible by 2.

Meteorological Observations. 239

Physiology will be interested in the result,, for it does away with
that inexplicable and most singular difference which seemed to exist
between the composition of the fatty bodies of man and the pig and
that of other animal fats. — Comptes Rendus, March 26, 1849.

METEOROLOGICAL OBSEBVATIONS FOB JULY 1849,

Chiswick. — July 1. Very fine. 2. Light clouds : very fine. S. Cloudy : slight
showers. 4. Cloudy : clear at night. 5. Clear : very fine. 6, 7. Very fine.
8. Very hot : clear at night. 9. Very fine : cloudless. 10. Dusky haze : clear.
11, 12. Very fine. 13. Cloudy. 14; Very fine, 15. Overcast. 16. Very fine.
17. Cloudy : showery. 18. Very fine : cloudy : heavy shower 5 p.m. : showery.
19. Showery. 20. Fine: dense masses of low white clouds: showery. 21. Cloudy:
showery. 22. Very fine : overcast. 23. Rain ; cloudy. 24. Cloudy : heavy
showers in forenoon : excessively heavy rain at night. 25. Fine : cloudy : showers
occasionally : heavy showers, with thunder in afternoon. 26. Fine : thunder
showers. 27. Overcast : very fine. 28. Very fine : cloudy. 29. Densely over-
cast. 30. Fine. 31. Very fine : cloudy.

Mean temperature of the month 62°'29

Mean temperature of July 1848 62*09

Mean temperature of July for the last twenty-three years ... 63 '23
Average amount of rain in July , 2'38inches.

Boston. — July 1 — 6. Fine. 7. Fine : thermometer 81° from 2 p.m. to 6 p.m.
8 — 12. Fine. 13 — 16. Cloudy. 17. Cloudy : rain a.m. 1 8. Cloudy : rain p.m.
19. Rain : rain a.m. and p.m. 20. Fine : rain a.m. 21. Fine : rain p.m. 22.
Fine. 23. Rain : rain a.m. and p.m., with thunder and lightning. 24, 25. Cloudy :
rain A.M. 26— 28. Fine. 29. Rain : rain a.m. and p.m. 30. Fine. 31. Cloudy.

Applegarlh Manse, Dumfries-shire. — July 1. Fine rain : high wind p.m. 2.
Rain during night : cleared and fine. 3. Heavy rain and strong wind. 4. Fine :
slight shower. 5. Fine : occasional showers. 6. Complete day of rain. 7. Very
heavy rain : high flood. 8. Fine and fair : pleasant air. 9, 10. Fine and fair.
11. Very fine summer day. 12. Very warm. 13. Warm, but cooler from east
wind. 14, 15. Warm. 16. Warm, but getting cloudy. 17. Heavy rain at
night : clear day. 18. Rain. 19. Showers: occasionally fair and warm. 20.
Showers: heavy p.m. 21. Fine and fair. 22. Drizzly: showery. 23. Fine a.m. :
showery p.m. 24. Showery. 25. Heavy showers : thunder. 26. Warm : slight
shower : thunder. 27. Fair: cloudy: cleared p.m. 28. Fair a.m. : rain p.m.
29. Heavy showers. 30. Heavy showers : thunder. 81. Heavy showers, less
frequent : thunder.

Mean temperature of the month 51°'0

Mean temperature of July 1848 56 '5

Mean temperature of July for twenty-five years ;... 58 "1

Rain in July for twenty years , 3'91 inches.

Sandwich Manse, Orkney.~3\x\y\. HaXn: Ai\zz\q. 2. Showers. 3. Rain. 4.
Bright: fine. 5. Clear: fine. 6. Cloudy : fine : cloudy. 7. Rain: cloudy:
showers : bright. 8, 9. Clear : cloudy. 10. Damp : cloudy. 11. Cloudy : fine.
12—14. Fine: fog. 15. Cloudy : clear. 16. Bright: rain. 17,18. Bright:
cloudy. 19. Clear: damp. 20. Drizzle: cloudy. 21. Drizzle: damp. 22.
Fine: drops. 23,24. Cloudy : drizzle. 25. Rain: clear. 26. Bright: damp.
27. Bright : showers. 28. Bright : rain.' 29. Clear : showers : fine. 30. Clear :
fine. 31. Showers.

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THE
LONDON, EDINBURGH and DUBLIN

PHILOSOPHICAL MAGAZINE

AND

JOURNAL OF SCIENCE.

[THIRD SERIES.]
OCTOBER 1849.

XXXII. On the Views of the Astronomer Royal respecting the
Modificatio7i of Sounds by Distance of Propagation. By
the Rev. J. Challis, M.A., F.R.S., F.R.A.S., Plumian
Professor of Astronomy and Experimental Philosophy in the
University of Cambridge^.

IN the Number of the Philosophical Magazine for last June,
the Astronomer Royal has stated it to be his belief that a
musical sound may degenerate into a hiss, abuzz, or a whisper^
and possibly into a roar, by mere distance of transmission.
So singular and novel a theory can hardly be expected to
pass current without being questioned. I consider myself
entitled to call it in question, because a short while before it
was promulgated I had proved in this Magazine, by what I
conceive to be strict mathematical reasoning, that musical
sounds do not by propagation become unmusical. The views
of the Astronomer Royal profess to be only conjectures, being
neither supported by mathematical reasoning, nor borne out
by any experiment, and on this account they cannot well be
brought under discussion. They are, however, based on a
piece of mathematical reasoning which the Astronomer Royal
has adopted from Mr. Stokes, ^nd which admits of being
discussed. Now I am prepared to show that this piece of
reasoning is faulty in its logic, and that it consequently affords
no pretext for the conjectures of the Astronomer Royal.

The rule of logic against which Mr. Stokes has offended
may be stated as follows : — When the equations applicable
to a proposed problem have been formed according to the
principles of the department of science to which the problem
belongs, and a solution of the equations has been obtained, it
is not allowable to accept the solution in part and reject it in
part : it is either wholly applicable or not at all. In the
* Communicated by the Author.

Phil. Mag, S. 3. Vol. 35. No. 236. Oct. 1849. R

242 Prof. Challis on the Modification of Sounds

instance of the hydrodynamical problem of the propagation
of sound in plane-waves, Mr. Stokes has violated the above
rule by accepting the analytical solution for certain values of
the co-ordinates and the time, and rejecting it for other values.
I proceed to make this assertion good.

The following is the enunciation of the problem. Assuming
that a medium in which the pressure p and density p are
related to each other by the equation p = a^f), is capable of
propagating waves in such a manner that the velocity and
density of the particles of the medium are functions of the
distance from a given plane, it is required to determine the
motion.

Let V be the velocity of any particle at the distance z from
the given plane, and at the time t reckoned from a given
epoch. Then by a known process, which it is unnecessary
to go through, we have for the case of propagation in a single
direction, the general solution,

t; = a . Nap. log p ==/(^2; — (ct + 1;) / + c^,

and giving to the arbitrary function a form corresponding to
a particular series of waves, we have the definite solution,

i:;=a.Nap. \ogp = m sin — (z—{a + 'o)t-\-c).

By these equations the velocity and density are given at all
distances from the given plane at any instant, and the solution
is in all respects complete. If, to ascertain the rate at which
a given velocity and density are propagated, we differentiate
the equations supposing v and p to be constant, it will be

found that the velocity v and corresponding density c*"" are
propagated with the velocity a-\-v. The effect of the diffei'-
ence of rate of propagation of different parts of the wave pre-
sents itself as a continuous modification of the form of the
wave. Mr. Stokes has exhibited this modification by a geo-
metrical curve (see Phil. Mag. vol. xxxiii. p. 359), and in so
doing has accepted the indications of analysis during an in-
terval equal to — — , but has rejected all its subsequent indica-
^ 27rW2 -^ ^

tions. To take a numerical instance, let « = 916 feet in a
second, m = 1 foot in a second, and A = 10 feet. Then it
would be admitted in this instance, that during an interval of
one second and six tenths, in which the wave travels over
14.59 feet, the analysis indicates truly, but not for any longer
period. This procedure Mr. Airy has signified his approval
of by saying, that "Mr. Stokes has shown that a distinct

hy Distance of Propagation, 24S

meaning can be given to the solution up to a certain point in
the progress of the wave." If we may believe these two ma-
thematicians, the wave at this point suddenly emancipates
itself from the control of analysis, and the subsequent motion
can be pursued by no other means than conjecture. Accord-
ingly each has favoured us with his conjectures. Mr. Airy's
are contained in the article which has given occasion to these
remarks, and Mr. Stokes's in the communication already re-
ferred to (Phil. Mag. vol. xxxiii. pp. 352-356).

It is not my intention to enter into any consideration of
these conjectures, which, in my opinion, can only be regarded
as proofs that the authors of them have fallen into an erro-
neous course of reasoning. In any legitimate application of
analytical calculation to a physical question, a spontaneous
failure of the analysis, leaving no resource but conjecture, can
never occur. Before such necessity has arisen, some fault in
logic must have been committed. I do not doubt that I point
out the fault committed in the case under discussion by saying,
that certain consequences deduced by analysis from the pre-
mises are received, while other consequences equally deduced
by analysis from the same premises are rejected. The ana-
lytical solution of the problem of plane-waves is, as I have
already stated, that the velocity xi at any point of the wave
and the corresponding density are propagated with the velo-
city a-\-v. In consequence of the different rate of propagation
of different parts of the wave, two different states of the me-
dium must occupy eventually the same position at the same
time. For instance, a position of maximum velocity is a po-
sition of no velocity when the interval t has become , — ; that

is, taking the numerical example before adduced, after the
lapse of two seconds and a half, when the wave has travelled
through 2290 feet. We are thus brought by the analysis to
an absurdity. It is true the absurdity is first consummated

at the end of the interval - — . Mr. Stokes avails himself of

this circumstance to limit his acceptance of the results of
analysis to this interval, and avoids the consideration of the
absurdity ; whereas right reasoning demands, if in any case
an absurdity is strictly deduced from premises, that a// results
from the same premises should be rejected. It is in vain to
urge, as Mr. Airy does, that the absurdity indicates the trans-
ition of the waves from a musical to an U7imusical condition.
A hiss and a roar are matters of experience and possible ;
they cannot therefore be symbolized by an impossibilit}'. The
only legitimate inference from the absurdity is, that the hj/po-

R2

244 Mr. B. C. Brodie on Myricine.

thesis of the problem is at fault; that it is not allowable to
make the supposition of plane-waves.

Mr. Airy's views, as I have said, are not borne out by any
experiment. On the contrary, an experiment may be adduced
which contradicts them. The possibility of hearing distinctly
words spoken at a distance, depends on the faithfulness with
which the air transmits the impressions made on it by the organs
of voice. As the difference between the sound of one letter and
that of another corresponds to a difference in the form of the
curve representing the succession and magnitudes of the con-
densations impressed, it is necessary that that form should
remain unchanged by distance of transmission in order that
words heard at different distances may be the same sounds.
The law of transmission expressed by the formula a + iy, which
is the basis of Mr. Airy's speculations, is opposed to this
constancy of form. M. Biot, however, has recorded an ex-
periment made at Paris, according to which, words pro-
nounced at one end of a cylindrical tube SI 20 feet in length,
were perfectly distinct at the other end.

Cambridge Observatory,
August 22, 1849.

XXX III. An Investigation on the Chemical Nature of Wax.
By Benjamin Collins Brodie, Esq.*
[Continued from vol. xxxiii. p. 391 .]
Ill.f On Myricine.

I HAVE placed the investigation of the Chinese wax be-
tween that of the cerotic acid and of the residue of the
bees'-wax which remains after that substance has been sepa-
rated from it. By the saponification of this Chinese wax we
procure, as I have shown, an acid identical with the cerotic
acid from bees'-wax, and also the alcohol of this acid, so that
the chemical history of these substances is closely connected.
We have moreover in the Chinese wax to deal with a sub-
stance found in nature in a state of great purity, the products
of the decomposition of which by alkalies and by heat can
readily be prepared and examined. The knowledge of the
relation of these products to one another throws great light
upon the nature of myricine, which is not a pure substance,
and the chemical relations of which are complex.

I have stated that the first extracts of wax with alcohol give
with acetate of lead an abundant precipitate in a hot alcoholic

* From the Philosophical Transactions for 1849, part i. j having been
received by the Royal Society May 11, and read November 23, 1848.

t Part I. was inserted in vol. xxxiii. p. 217, and Part II. at p. 378 of the
same volume of this Journal. — Ed.

Mr. B. C. Brodie on Myricijie. 245

solution. This affords us a ready test of the presence of the
cerotic acid. The wax may be long boiled with alcohol before
the whole of the cerotic acid is removed. If however this
process of boiling and decantation be continued, a time will
come when the acetate of lead will cease to give any precipi-
tate whatever in the hot alcoholic extract. The residue after
this extraction I speak of as myricine. It is advisable to con-
tinue for two or three times the operation of boiling and de-
canting, even after the acetate gives no precipitate, the cero-
tate of lead not being entirely insoluble in the hot solution.

The myricine thus prepared is a greenish substance of about
the consistency of wax, uncrystalline, still possessing a slight
smell of wax, and of a melting-point of 64-° C. This substance
is hardly acted on by dilute potash. It is however saponified
by boiling with strong potash, and more readily by an alco-
holic solution of the alkali. The saponification may also be
effected by melting it with hydrate of potash, as in the case of
the Chinese wax. The products are the same in whichever
way the operation be conducted.

If the soap from the saponification of the myricine be treated
in the same manner as the similar soap from the Chinese wax*,
it also will be found to contain two substances, an acid and
another substance which is contained in the aether with which
the baryta salt is extracted. On attempting to purify these
substances respectively by crystallization out of alcohol, aether
or absolute alcohol, great variations in the melting-point both
of the acid and of the basic substance will be observed. And
careful observation shows that these are not, as in the case of
the Chinese wax, substances in a state of comparative chemical
purity, but are mixtures, both in the case of the acid and of
the other matter, of at least two bodies difficultly separable
from one another. It is the separation of these substances
which gives a peculiar difficulty to the investigation of the
nature of myricine.

Although the acid and basic products of the saponification
may thus, as in the case of the Chinese wax, be separated by
precipitation of the soao by a baryta salt, in the case of the
bees'-wax these substances admit of a simpler method of sepa-
ration, without which method, so difficult is it to wash per-
fectly out the baryta salt, that I question whether the sub-
stances could be obtained pure. The soap, in whatever way
the saponification may have been effected, and after the alcohol,
if any, used for the saponification has been distilled off", is to
be dissolved in a large quantity of water, and the boiling so-
lution decomposed by an acid. The melted mass which re-
* Phil. Mag. vol. xxxiii. p. 381.

246 Mr. B. C. Brodie o?i Myricine.

suits from this operation, after having been repeatedly boiled
out with water, is to be dissolved in a large quantity of hot
alcohol. An abundant precipitate appears in the cold fluid
from which the solution is to be filtered, and the precipitate
repeatedly redissolved and recrystallized out of alcohol. 1 he
precipitate will at length be found to consist, almost entirely,
of the basic portion of this waxy matter. The alcoholic solu-
tion contains the acid.

I shall proceed to give the simplest method by which the
pure substances may be obtained, and those experiments which
1 have made upon their constitution, which I think can leave
no doubt upon the mind of the chemist as to the true nature
of that matter of which by far the greater portion of the my-
ricine and, indeed, of the wax itself consists.

The first separation of the products of saponification may
be made, as I have stated, by combining the acid with baryta
and washing out the resulting salts with aether ; the basic
portion of the products may be obtained as pure by this as by
the other method.

Melissine.

If the substance contained in the aetherial solution, with
which the baryta salt is washed out, be crystallized out of
aether or alcohol, the melting-point will be considerably raised,
from below 70° C. to above 80°, by repeated crystallization.
The difficulty with which the melting-point was raised, made
it evident that the substances contained in the solution were
to be separated only by long crystallization and a careful at-
tention to the variations of the melting-points. I made various
experiments to discover a satisfactory method of purification.
At length I found that if the aetherial solution be filtered while
yet warm, and when only a small portion of matter has cry-
stallized out, a substance remains on the filter of a melting-
point of 85° C. of a satiny lustre, and of highly crystalline
appearance. It is with difficulty that even a small portion of
substance can be thus obtained, and it is necessary to use,
during the filtration, a hot water apparatus to prevent the pre-
cipitation of the whole matter dissolved. I have never been
able to succeed in further raising the melting-point of this body,
and therefore regard it as pure. In this condition it crystallizes
on cooling from the melted state, and its crystallization is
marked by striae parallel to the line of cooling; it being in all
respects, but the melting-point, similar in appearance to cero-
tine as procured from Chinese wax.

I give this method of preparing this substance as it was the
first I adopted, and as it can thus be procured in a high state

Mr. B. C. Brodie on Myricine. 247

of purity. I afterwards however discovered the use of rectified
coal naphtha as a solvent for these substances, and by far the
best and simplest method of procuring the body is by crystal-
lization out of that solvent, of the precipitate from the alco-
holic solution which I have before mentioned, as procured by
dissolving in alcohol the wax matter obtained by decomposing
by an acid the soap from the myricine By alcohol the basic
portion of the saponified myricine is separated from the acids.
By naphtha the substance of 85° melting-point is separated
from another and probably an analogous body, of which I
shall speak hereafter.

This substance gave to analysis the following numbers.
The result is the same in whatever way the substance is pre-
pared.

Substance.

CO2.

HO.

I. 0*2685 grm. gave .

0*8075

0*341

II. 0*2597 grm. gave .

0*7839

0*3326

III. 0-278 grm. gave .

0*84375

0-35325

IV. 0*2584 grm. gave .

0*7812

0-325

V. 0*2511* grm. gave .

0*7595

0-3215

VI. 0-261 7t grm. gave .

0*7870

0*3295

which give in 100 parts —

I. If. TIL

IV.

V. VI.

Carbon . 82-02 82-40 8277

82-43

82-48 8201

Hydrogen 14-11 14-25 14' 11

13-97

14-22 13-99

Oxygen . 387 335 3-12

3-60

3-30 400

10000 100-00 10000

100-00

10000 10000

These analyses agree with the formula —

Atomic weighl

t. Calculated.

Cfio . . . 360

82*19

Hg^ . . . 62

14.*15

O2 . . . 16

3*66

438 100-00

This substance I propose to call Melissine.

Melissic Acid.

Melissine, heated with lime and potash, as the similar ex-
periment was made with cerotinej, is, like that body, con-

* This substance was procured directly from wax, from which it may be
obtained and purified in the same manner as from the purified mjriciue;
which is the simplest way of procuring the substance if the other products
of saponification are not required.

f This substance was procured from the Ceylon wax mentioned in a
former paper.

X Phil. Mag. vol. xxxiii. p. 381.

248 Mr. B. C. Brodie on Myricine.

verted into an acid. TJiis acid has a similar appearance to
the wax acid already described. It has however a much
higher melting-point, namely, 88°-89° C. The preparation
of the substance need not be again described.

CO2. HO.

I. 0*2655 grm. gave 0-7764. 0-3104

II. 0-2507 grm. gave (another preparation) 0*728 0-2507

III. 0-2508 grm. gave 0-7333 0-3077

IV. 0-2396 grm. gave (another preparation) 0-7026 0*2885
V. 0-258 grm. gave 0-3085

which give in 100 parts —

I.

II.

III.

IV.

V.

Carbon .

79-74

79-19

79-74

79-97

Hydrogen

13-00

13-32

13-63

13-40

13-28

Oxygen .

7*26
100-00

7-49

6-63

6-63

100-00

100-00

100-00

These analyses agree

with the fori

mula —

Atomic weight,

Calculated.

CgQ .

. 360

79-64

Hflo •

60

13-27

O4 .

32
452

1

7*09

0000

I prepared the silver salt of this acid in precisely the same
manner as was prepared the silver salt of the cerotic acid.

1. 0-6085 grm. gave 0-1175 silver.

II. 0-678 grm. gave 0-1315 silver.

III. 0-58625 grm.gave (another preparation) 0-11575 silver.

which give in 100 parts —

I. II. III.

Silver 19-30 19*39 19-74

CO2. HO.

I. 0-4619 grm. of the salt gave 1-0863 0-4464

II. 0-484 grm. of the salt gave 1-13375 0*471

giving in 100 parts —

I. II.

Carbon 64-13 63*90

Hydrogen .... 10*73 10*81

Oxygen and silver . 25*14 25-29

100-00 100-00

These analyses lead to the formula C^ H^g O4 kg.

Mr. B. C. Brodie on Myricine. 249

Calculated.

Cfio 64-38

H59 10-55

O4 5-77

Ag . . . . . 19-30

100-00

The formula therefore of the hydrated acid is Cb.oH6o04.
This acid I call Melissic Acid.

Chlor-Melal.

By the action of chlorine on melissinea perfectly analogous
result is obtained to that obtained by the action of chlorine on
cerotine. The substance undergoes also a similar change in
appearance, being converted into a resin.

The substance was prepared and analysed with a view to
confirming the formula of the body.

CO2. HO.

I. 0-4-136 grm. gave 0-589 0-175

II. 0-4263 grm. gave 0*602 0-1835
which give in 100 parts —

Carbon 38-83 38*51

Hydrogen .... 4-70 4-78

Oxygen and chlorine 56-47 56-71

100-00 100-00

I. 0'6663 grm. gave 1-4821 grm. of chloride of silver equi-
valent to 0*3665 grm. of chlorine.

II. 0*6075 grm. gave 1*341 grm. of chloride of silver equi-
valent to 0*3316 grm. of chlorine.

III. 0-6475 grm. gave 1-4375 grm. of chloride of silver
equivalent to 0*3555 grm. of chlorine.

These determinations correspond in 100 parts to —

I. II. III.

Chlorine . . . 55*01 54-58 54*91

These analyses lead to the formula

r J "45*5 o

Cgo . . . . 38-50

H45J. . . . 4-86

Cli44. . . . 54-90

O2 . . . . 1-74

100-00
As in the case of the cerotine, by the action of chlorine two

230 Mr. B. C. Brodie on Myricine.

equivalents of hydrogen are removed without replacement by
chlorine, while the further action is an action of substitution,
the substance being the analogue of chloral.

The products of the distillation of melissine are analogous
to those of the distillation of cerotine. The substance partly
distils over unaltered, and is partly, with the loss of water,
converted into solid hydrocarbon. Sulphuric acid also com-
bines with it under the same conditions as with the other wax-
alcohol.

Palmitic Acid from the Saponification of Myricine.

Melissine is soluble with such great difficulty, in every sol-
vent suitable for washing out the baryta salt from the wax
soap, that its separation from the acid cannot in this manner
be effected. It may however be separated by simple crystal-
lization. The alcoholic solution (p. 24-6) from which the me-
lissine has crystallized out, after having been considerably
concentrated and again filtered from any precipitate produced
on cooling, contains hardly a trace, if any, of that substance.
The acids are very soluble in alcohol, and it is only on great
concentration that they crystallize from that solvent. The
alcohol is to be distilled off to the point of crystallization, and
the first portions only of the fat acid selected for the prepara-
tion of the pure substance. The acid is to be boiled with
potash, combined with baryta, and washed out with aether.

On decomposing the baryta salt with hydrochloric acid, a
fat acid separates, having the appearance of margaric or pal-
mitic acid, which latter body is in truth the principal acid of
the wax. It is however mixed with another acid of a lower
melting-point, for which reason it is desirable, as I have men-
tioned, to use in its preparation only the first crystallization
of the acid. From this other body it is separable with the
greatest difficulty; but by long-continued crystallization from
aether, an acid may be obtained of the melting-point of 62° C,
beyond which point it cannot be raised. This acid gave to
analysis the following results: —

CO2.

HO.

I. 0-2486 grm.

gave .

. 0-6877

0-278

II. 0-2605 grm.

gave .

. 0-7145

0-290

III. 0-2542 grm.

gave .

. 0-6937

0-2847

giving per cent. —

I.

11.

III.

Carbon . .

75-42

74.-80

74-43

Hydrogen

12-4-3

12-36

12-43

Oxygen . .

12-15

12-84

12-14

100-00 loo'oo 190-00

Mr. B. C. Brodie on Myricine. 251

The silver salt was made as in the other cases by precipi-
tation from the ammoniacal solution of the acid.

I. 0'6885 grm. of this salt gave .... 0*2005 silver.
II. 0*66025 grm. of the same gave . . . 0*1920 silver.

III. 0*623 grm. of another preparation gave 0*182 silver.

IV. 0*609 grm. of the same gave . . . 0*17625 silver.
V. 0*671 grm. of another preparation gave 0*197 silver.

VI. 0*744' grm. of the same gave . . . 0*2185 silver,
giving in 100 parts —

I. II. III. IV. V. VI.

29*12 29*23 29*21 28*94 29*35 29*36

CO2. HO.
I. 0*4458 grm. of the first preparation gave 0*869 0*3495
II, 0*4463 grm. of the same preparation gave 0*870 0*3555
III. 0*5896 grm. of thesecondpreparation gave 0*7545 0*3065
which correspond in 100 parts to —

I. 11. III.

Carbon 53*16 53*22 52*82

Hydrogen .... 8*70 8*85 8*75

Silver and oxygen . . 38*14 37*93 38*43

100*00 100*00 100*00
The silver salt is by no means insoluble in the ammoniacal
solution, so that in the making of the salt by this method a
certain separation of the substance is effected. If any impu-
rity were presented, it probably would be detected on analysing
the acid as again separated from the silver salt.

CO2. HO.
I. 0*2523grm. of the acid thus separated gave 0*6970 0*285
11.0*228 grm. of the same gave . . . . 0*6255 0*257
giving in 100 parts —

Carbon . . . .75*88 74*82

Hydrogen . . 12*56 12*52

Oxygen . . . 12*06 12*66

100*00 100-00

These analyses, as well as those of the acid previous to
combination with silver, agree with the formula of palmitic
acid, C32 H32 O4, with which substance the melting-point of
the acid also identifies it. The calculated numbers in parts
per cent, of the acid and silver salt are —

C32 . . 192 75-0

H32 . . 32 12*5

O4 . . 32 12*5

256 1000

252 Mr. B. C. Brodie on Myricine,

^32

. 192

52-8

H31 .

. 31

8-5

0,-. .

. 32

9-0

Ag .

. 108-1

29-7

363-1 100-0

Distillation of Myricine.

The discovery of the cerotic acid rendered it evident that in
order to obtain the products of distillation of myricine, and
especially the acids in a state of purity, it was necessary first
to remove that body and to distil only the residue of the wax.
I give the results of this experiment made with myricine. The
first portions of the distillate consist almost entirely of acids,
the latter of hydrocarbons. During the distillation a smell of
butyric acid may be perceived. This however appeared to
me to diminish when the boiling of the wax with alcohol had
been very long continued. It is possible to effect nearly a
complete separation of the acids and the hydrocarbons by di-
stillation. It is however not advisable to proceed in this
manner, but it is best after boiling the distillate with water to
saponify the whole by potash. The soap may be removed
by a syphon from the hydrocarbons which float on the surface.

Palmitic Acid from the Distillation of Myricine.

The acid, having been purified in the usual manner by
washing out the baryta salt with aether, and the subsequent
methods of purification, presents an appearance similar to the
acids obtained by saponification. By crystallization the melt-
ing-point may be raised to 62° C.

CO2. HO.

I. 0-2592 grm. of this acid gave 0*7165 0-2931
II. 0-250 grm. of this acid gave 0-6865 0-27925
III. 0-2775 grm. of this acid gave 0*75925 0-311

These analyses correspond in 100 parts to —

I. II. III.

Carbon . . 75-39 74-89 74-61
Hydrogen . 12-58 12-40 12*45

Oxygen . . 12*03 12*71 12-94

100*00 100-00 100*00

The silver salt of this acid, prepared as before, gave the
following results : —

I. 0*5006 grm. of the substance gave . . 0*1479 silver.
II. 0*2295 grm, of another preparation gave 0*0685 silver.

Mr. B. C. Brodie on Myricine, 253

which correspond in 100 parts to —

I.

Silver . . . 29-54-

II.

29-84

0-3505 grm. of the same salt gave

CO2.
. 0-6873

HO.
0-2758

which gives in 100 parts, —

Carbon ....
Hydrogen . . .
Oxygen and silver

53-47

8-74

37-79

100-00

These numbers prove the identity of the acid from the di-
stillation of myricine with that obtained from the saponification
of that substance (p. 251).

There are great dilficulties in the way of obtaining even a
sufficient quantity of this acid for the determination of its for-
mula. To obtain even a very small portion of it of which the
purity may be relied on, it is necessary to operate on a large
quantity of the impure acid : for the preparation of this pure
myricine is required, free from cerotic acid, which it is not
easy to get in any quantity.

These difficulties have prevented me making any further
experiments with this acid, theidentity of which however with
palmitic acid, as obtained by Fremy and Stenhouse from palm
oil, and by Sthamer from Japan wax, is made out. I subjoin,
for the sake of comparison, the silver determination of the
silver salt of the palmitic acid as obtained by these chemists.

Fremy*. Stenhousef. Sthamer {.

Silver, per cent. 29*00 29-23 29-42 29*28 29*51

This acid appears also to be the same as the acid obtained
by Varrentrapp§ from the oxidation of oleic acid by means of
lime and potash, which also had the melting-point of 62° C.
The silver determinations of this acid gave as the per-centage
of silver,

29-27 29-45 29-13,

numbers identical with my own.

Melene.

It is well known that one of the principal products of the
dry distillation of wax is a solid hydrocarbon. Ettling, who

* Liebig's Annalen, vol. xxxvi. p. 45. Silver determinations, V. VI. VII.
t Ibid. p. 52. The mean of five determinations closely agreeing. This
acid melted at 60° C.

X Ibid. vol. xliii. p. 342. The mean of three determinations.
§ Ibid. vol. XXXV. p. 209.

25€ Mr. B. C. Broclie 07i Myricine.

first analysed this substance*, concluded from its melting-
point, analysis, and general appearance, that it was identical
with paraffine, a hydrocarbon then recently discovered by
Reichenbach in the products of the dry distillation of wood.
The wax hydrocarbon has therefore borne the name of pa-
raffine.

This substance was supposed, from the analyses of Ettling
and J. Gay-Lussac, to be isomeric with olefiant gas.

Recently, however, this has been contested by Lewy, who
analysed paraffine from various sources, and showed it, as he
conceived, to contain a larger amount of hydrogen than had
been previously supposed. In truth the average of his analyses
gave,—

Carbon .... 85*03
Hydrogen . . . 14;'87

99-90

numbers inconsistent with the old idea. The question how-
ever is, whether M. Lewy experimented with a pure chemical
substance, for which there is no guarantee.

My own experiments confirm the analyses of Ettling, and
the constitution originally assigned to the substance, to which
theoretical considerations also lead. But I cannot see any
reason to believe the wax hydrocarbon to be identical with
the paraffine of Reichenbach. This name of paraffine has
been applied indiscriminately to the whole class of solid hy-
drocarbons, which have, or have nearly the formula C,„H^,
the identity of which has been taken for granted, in the abs-
ence of any true knowledge as to the chemical nature of the
substances from the decomposition of which by heat they are
produced. The different melting-points however of these
substances point out to us at once a distinction between them.
The paraffine of M. Lewy melted at 46°'8. A specimen of
the paraffine of wood given to me by Professor Liebig, and
which that gentleman received from Reichenbach, its disco-
verer, melted at 43°-5 C. ; Ettling's paraffine at 57° to 58" C.
I confess it is difficult for me to conceive what substance in a
state approaching to purity Lewy analysed from the wax
having the melting-point he has given, since nothing is easier
than to raise the melting-point of the paraffine from the wax
to 56° C, although beyond this any change is effected with
difficulty.

Cerine alone gives on distillation hardly a trace of this hy-
drocarbon, while it forms a principal product of the distillation
of myricine. The palmitic acid is separated by saponification!

* Liebig's Annalen, \o\. ii. p. 259.

Mr. B. C. Brodie on Myricine. 255

and the general preparation of the substance is the same as iu
the similar case of the cerotene from Chinese wax, to which
substance it is closely analogous. If the hydrocarbon from
the distillation of the pure myricine, the acids having been
boiled out with potash, be pressed out in a press between
blotting-paper, it will have a melting-point of about 56° C.
This can be raised by further crystallization out of aether to
60° C. The analysis of the substance in this condition shows
the presence of some body containing oxygen, in addition to
the hydrocarbon.

CO2. HO.

0-2606 grm. of this substance gave 0*8094 0*3402

giving in 100 parts, —

Carbon . .

. . 84*74

Hydrogen

. . 14*51

Oxygen . .

. . 0*75

100*00

Another analysis gave similar results. This led me to pre-
pare the substance in rather a different manner. The pa-
raffine having been carefully pressed out in the manner de-
scribed, was rectified over potassium, which destroys the
oxygen compound. The distillate is perfectly white: it con-
tains a little oil, which may again be pressed out. By crystal-
lization out of pure aether, the melting-point may now be
raised to 62° C. This substance was analysed.

CO2. HO.

0-261 grm. gave . . 0*8165 0-3393

giving in 100 parts, —

Carbon .... 85-31
Hydrogen '. . . 14*44

99-75
The formula C^H™ demands —

C^ 85-71

H„ 14-28

99-99

The difference between the hydrogen calculated and found
is only 0-16 per cent., which is as near to theory as such ana-
lyses can be expected to come. Cerotine melts at 81° C.
The hydrocarbon I have called cerotene melts at 57° to 58*^'.
Melissine melts at 85°. The wax hydrocarbon at 62° C,
showing a precisely analogous difference in their melting-
points. Owing to the numerous operations which are neces-

256 Mr. B. C. Brodie on Myricine.

sary before this hydrocarbon can be procured in a pure state,
I have been unable to make further experiments with the pure
substance. The analyses, however, the analogy of this other
substance and the mode of its formation, can leave no doubt
but that it is the hydrocarbon of the wax alcohol CgQ Hgg, to
which may be given the name of melene.

The Nature of Myricine.

The analogy of the products of the decomposition of myri-
cine by alkalies and by heat, to those of the Chinese wax and
of spermaceti under similar circumstances, would lead us to
suspect that a similar relation exists between the substances to
which these products are due. If, however, we take the
numbers which have been obtained by analysis for this body,
those for example of Ettling*, or those of Lewy f, and attempt
from these to reckon out a formula which shall give a rational
account of these decompositions, we find a considerable defi-
ciency of carbon. I give one of Lewy's analyses, with which
other analyses of himself and other chemists are sufficiently
accord ant if .

Carbon . . . . 80-28

Hydrogen . . . 13'34<

Oxygen .... 6-38

100-00

The formula C92 H92 O4, which would account in a simple
manner for the decompositions, —

^32 "31 ^3

Ceo Hgi 0
C92 H92 O4

^32 "32 ^4

C'60 "60

C92 H92 O4

requires —

Atomic weight.

Cgg .

81-65

SS'l

H92 . .

13-60

92

0, . .

14-75

32

100-00 676

leaving a difference of one and a half per cent, of carbon, a
difference too great to be attributed to any accidental error.

I have stated that the decompositions of the myricine are
far from being so simple as those of the Chinese wax, and that
in order to obtain either the acid or the wax alcohol, long
and repeated crystallizations are necessary. This at once led

* Liebig's Annalen, vol.ii. p.267. t Annates de Chimie, vol.xiii. p. 443.

t Ibid.

Mr. B. C. Brodie on Myricine. 257

me to the suspicion that the so-called myricine was no pure
chemical substance, but a mixture of two or more bodies.
Subsequent experiment confirmed this view.

The residue of the wax, after the cerotic acid has been
boiled out by alcohol, melts at 64° C. It is but very slightly
soluble in alcohol. Pure aether, however, will dissolve it with-
out much difficulty. It crystallizes out of this reagent in
light feathery crystals. The precipitate and the residue from
the solution, evaporated to dryness, have different melting-
points. I succeeded in this manner in raising the melting-
point of the precipitate to 71°'5. This end may be more
readily obtained by adding a small quantity of naphtha to the
aether.

The following analyses were made of a substance of 72°,
which after repeated crystallizations was precipitated on the
filter out of the hot solution, the filter being kept hot by means
of a hot water apparatus. I have not succeeded in raising the
melting-point beyond 72°. The substance is now highly cry-
stalline in appearance, which the impure myricine is not, and
of about the consistency of wax. I regard it in this state as
pure.

COj. HO.

I*. 0-2592 grm. of substance gave 0-7735 0'3135

II. 0-2243 grm. of substance gave 0'672 0-269

which give in 100 parts, —

Carbon ... 81-38 81-70

Hydrogen . . 13-44 13-33

Oxygen . . . 5-18 4-97

100-00 100 '00

These numbers are very different from any which have been
before obtained for any substance from the myricine, and dif-
ferent from those which I myself have obtained for substances
of a lower melting-point. The crystalline appearance marks
the purity of the substance, and notwithstanding the slight
diflfierence in the hydrogen, I cannot but regard it as the body
C92 H92 O4, with the calculated formula of which, as given
above, it sufficiently agrees. I must add that the substance
is separable with extreme difficulty. The next precipitate

♦ The thorough combustion of these waxes is difficult, and I have made
many experiments to ascertain the best method of analysis. Bichromate
of lead was the material generally employed. But when the combustion is
made very slowly, I believe it to be complete even with oxide of copper
alone. The greater number of such analyses in this investigation were
made by ray chemical assistant, Mr. L. Hoffmann, to whose care and skill
I am much indebted.

Phil. Mag. S. 3. Vol. 35. No. 236. Oct. 1 849. S

258 Mr. B. C. Brodie o» Myricine.

from the solution from which the above substance had been
separated, had a melting-point half a degree lower, and gave
to analysis rather less carbon, namely, C. 81°-0 per cent.

The greater part of the difficultly saponifiable portion of
the wax appears to consist of the substance, the analysis of
which I have just given, and to which we may confine the
name myricine. We have, however, clearly some other body
present accompanying it, the products of the decomposition
of which by potash are to be found with both the acid and
the wax-alcohol procured by saponification of the impure sub-
stance, which, as I have said, render extremely difficult the
preparation of these bodies in a pure state. I shall proceed
to give some experiments which throw some true light upon
the nature of this substance, although I cannot say that its
history is satisfactorily made out. The solution of aether or
naphtha (p. 247) from which the melissine of 85° has been
separated, still contains a large quantity of substance of a
similar appearance, but of a melting-point much lower than
that of the melissine itself Notwithstanding however the
differences in the melting-point, analysis shows us but little
or rather no difference in the constitution of the different por-
tions of this substance. In the case for example of a substance
melting at 78°-5 C, —

CO2. HO.

0-2522 grm. gave . . 0*764 0*324

which gives in 100 parts, —

Carbon .... 82-59
Hydrogen . . . 14-27
Oxygen .... 3-14

100-00

In the case again of a substance melting at

72°,-

CO2.
0-249 grm. gave . . 075075

HO.
0-317

which gives in 100 parts, —

Carbon .... 82-22
Hydrogen . . . 14*14
Oxygen .... 3*64

100*00

Other analyses gave similar results.

These analyses do not differ seriously from one another,
and give precisely the numbers of the melissine itself (p. 247).

Mr. B. C. Brodle on Myricine. 259

The numbers however are consistent with various formulae
besides that of the melissine. At 72° the melting-point is
extremely constant. A portion of substance was obtained at
this melting-point by repeatedly filtering the aetherial solution
from the melissine which first crystallized out of the hot liquid.
A time arrived when there was no difference between the
melting-point of the portion which first crystallized out of the
hot solution and which was on the filter, and that which after-
guards crystallized out of the fluid which had passed through.
The melting-point in both cases was 72°. B}' heating with
lime and potash, as in the case of melissine, this substance of
72° also affords an acid, which after the usual preparation,
gives very different numbers to those of the melissic acid.
This acid melts at 77°'5.

CO2.

HO.

I. 0-256 grm.

gave .

0-735

0-3015

II. 0-267 grm.

gave .

0-765

0-311

III. 0-2551 grm.

gave .

0-730

0-2995

in 100 parts, —

I.

II.

III.

Carbon . .

78-28

78-U

78-05

Hydrogen .

13-09

12-94

13-05

Oxygen . .

8-63

8-92

8-90

100-00 100-00 100-00

Between the second and third analyses the substance was
twice crystallized out of aether. The substance dissolved by
the aether had the same melting-point of 78° as the substance
on the filter.

The silver salt of this acid gave the following numbers: —

CO2. HO.

I. 0'5054 grm. of substance gave 1-127 0-4572
II. 0*5182 grm. of substance gave 1-1505 0-467

giving in 100 parts, —

I. II.

Carbon 60-80 60-56

Hydrogen .... 10-05 10-01

Oxj'gen and silver . 29-15 29-43

100-00 100-00

I. 0-617 grm. gave on ignition 0-1375 silver.
II. 0*7315 grm. gave on ignition 0*1625 silver.

giving per cent. —

I. II.

Silver . . 22-28 22-21

S2

260 Mr. B. C. Brodie on Myricine.

These analyses perfectly agree with the formulae for the
acid, C^j, H49 O4.

Calculated.

C43 . :

. . 78-4

H49 . ,

. . 13-0

04 . .

, . 8-6

100-0

Calculated

C49 . .

, . 60-9

H48 .

. . 9-9

04 . .

. . 6-8

Ag . .

. . 22-4

100-0

If we compare the numbers of this acid with those of the
substance from the oxidation of which it was derived, we shall
see that it is impossible to account for the changes in the same
simple manner as in other cases of such transformation. It
would not be difficult to reckon out a formula that without
great violence should account for it, but it is hardly worth
while to do so, since notwithstanding the perfect agreement of
the calculated and theoretical numbers, it is impossible to
assert with certainty that either it or the body from which it
is derived are pure chemical substances. There is too great
a difficulty in the perfect separation of the melissine to lead us
to hope that it can absolutely be removed by the method I
have given. I failed in attempting to procure in larger quan-
tities this substance of 72°. The melting-point was very con-
stant at 75°, but on oxidizing a considerable quantity of this
substance with lime and potash, acids were procured, which
by crystallization were separable in the same manner as the
substance from which they were derived, and the purification
and perfect separation of which presented the same difficulties.
I obtained in this way an acid having nearly the melting-point
of 85°, the melting-point of melissic acid, and also an acid
with a lower melting-point than 77°, but of which the melting-
point was not so absolutely constant as to induce me to inves-
tigate it further. I give however these analyses, since they
unquestionably prove the existence of some other body in ad-
dition to the melissine, in the products of the saponification of
wax, which by oxidation is capable of passing into an acid
belonging to the series Qrn^mO^. Since it is only a pure
body or a mixture of acids of this series which could give rise
to the results I have given, and from the great difficulty of
separation, the acid in all probability contains a very large

Mr. B. C. Brodie 07i Myricine, 261

number of equivalents of carbon, whether it have precisely the
formula I have above given or not.

Mixed with the palmitic acid of 62^, is found another acid
of a much lower melting-point, and which presents similar
difficulties of separation from the palmitic acid to those of the
substance mixed with the melissine from the melissine itself.
This acid is very soluble in alcohol, unctuous to the touch,
and of a very low melting-point. I do not, however, mean to
assert that the other wax-alcohol exists in the wax in combi-
nation with this unctuous acid, the presence of which is very
probably due to another source.

This alcohol may possibly, as well as the melissine, be com-
bined with palmitic acid, or it may be in some altogether dif-
ferent form in the wax. Even after long boiling with alcohol,
the myricine has a slight wax smell, and it is possible that
this unctuous acid is the product of the action of potash upon
the oil which is one of the constituents of the wax, and from
which I have in fact procured an acid of this nature. This
oil, or rather grease, which was analysed by Lewy, is a very
curious substance. The other constituents of the wax are, in a
pure state, inodorous and crystalline, and to it the wax owes its
tenacity and peculiar smell. I have made some experiments
as to its nature, and procured from it also an acid and an un-
saponifiable substance; I will not, however, here enter upon the
matter, hoping at some future timetoresumeits investigation.

I must not omit to mention, with reference to the bees'-
wax from Ceylon, of which I spoke in a former paper, and
which contained no cerotic acid, that it possesses all the general
characters of the other portion of the wax. Like the impure
myricine, it contains more than one substance. The wax itself
has a melting-point of Qb^'S. When digested with aether in
the cold, a portion is taken up by the aether, and a residue
left of the melting-point of 67°; and, when dissolved in aether,
if the aetherial solution be filtered while warm from the first
portions of the precipitate which crystallizes out, a substance
may be obtained, of the melting-point of 72°, crystalline in
appearance, hardly at all acted on by a solution of potash,
but readily saponified by melted potash ; resembling in short
in all its properties the pure myricine. The products of the
saponification of the wax itself closely resemble those of the
impure myricine, and present similar difficulties of separation.

An acid may be obtained from it having the character of
palmitic acid, and I have also procured from this wax the
substance melissine, having a melting-point of 84<°. The ana-
lysis VI, p. 247, was made from a preparation from Ceylon
wax.

262 Mr. B. C. Brodie on Myricine.

I will sura up the results of this investigation by giving a
list of the principal substances of which an account has been
given in this and the preceding papers. This table will exhibit,
at one view, their relations to one another, and to the natural
substances from the decomposition of which they are derived.

Cerotic acid [cerine] . . . =C54H54 04.
Chlor-cerotic acid . . . . ^^^^^Qf^O^.

Cerotic aether ..... =C^^^^^O^=^^^^^q^'

Chlor-cerotic aether . . . =(::^J^fO^^\^^^C\^P'^'

"-^^i^ [C4H5O.

Cerotine =:-Cc^Yi^Oc,.

Sulphate of oxide of cerotyle = SO3, C54 H55 O + HO.

Chlor-cerotal =CtA{^\^ ^t

Cerotene [paraffine] . . . =0541154.

fC /^35-
^^1 Cl,9.

Chlor-cerotene =<) Cc^\^f'

n / "82-
-^^ IC),,.

Chinese wax =^^^^^^^^^= {c'^lo':

Melissine ^^m^e^^v

Chlor-melal =C6o|Sl^'' O,.

Melissic acid = Cg^ Hgo O4.

Melene [paraffine] . . . = CgQ HgQ.
^Palmitic acid = C32 Hgg O4.

Myricine (pure) .... ==C^^U^O^^i^^^^^'^^'

1 might add to this list the acid C49 H^^ O4, the constitution
of which however, for the reasons 1 have given, I cannot con-
sider to be made out with sufficient certainty.

We should naturally suspect some intimate chemical rela-
tion between wax and fat from their similar appearance and
properties. This suspicion gave rise to the idea that wax was
convertible into fat, and to the hypothesis that wax was to be

Mr. B. C. Brodie om Myricine. 263

regarded as the aldehyde of stearic acid, and was capable of
passing into that substance by a simple process of oxidation,
a view of its chemical nature entirely without foundation.
From the preceding inquiry, we arrive however at the know-
ledge of a no less remarkable relation between these substances.

Margaric acid was recently the last of that singular series
of acids of the type Cm^mO^.) which commencing with formic
acid comprehended acetic acid, the volatile acids of butter and
the acid of spermaceti, and aethal was the last of the corre-
sponding alcohols. In the wax acids and alcohols of which
an account has been given in this and the preceding papers,
we have bodies at the other extremity of the series standing
in a similar relation to margaric acid and to aethal, as that in
which acetic and butyric acid, and alcohol and potatoe oil
stand to them at the commencement. An intervening acid
of the series, the acid C44 H44 O4, has lately been discovered
by Volcker* in the oil of the Guilandina Moringa, and the
investigation of the numerous class of vegetable oils and waxes
will doubtless afford other bodies of the group.

Notwithstanding the many different properties of these sub-
stances, we find their chemical analogies constant, and the
mutual relation of the acid, the alcohol and the hydrocarbon,
is the same between bodies containing sixty as between those
containing only four equivalents of carbon. Through at least
half the series, from thirty to sixty equivalents, the same phy-
sical type of fat prevails. As a fat is doubtless but a soft kind
of wax, so may not alcohol be but a very fluid form of fat ?
Alcohol has not yet been solidified, but one cannot help sus-
pecting that when solidified it will appear as a wax or fat.

Direct experiment has shown us that in the body of the bee
sugar is converted into wax. A simple analysis of the two
substances showed that the carbon and hydrogen were in the
same ratio in both, and that the change could be effected by
a simple deoxidation of the sugar. Of the way in which this
change is eflfected we are ignorant. The true formula of these
wax substances however shows that they belong to the very
type of bodies which are the ordinary products of fermenta-
tion, and are connected with them by the strongest chemical
analogies. A new mode of fermentation produced butyric
acid out of sugar; might not another kind of fermentation
produce wax?

Until we know the nature of the whole of the ingredients
of the wax, it is useless to speculate on the law of such a
change. Although the wax itself is no pure chemical sub-
stance, but a mixture of substances differing nearly three per
* Liebig's Annalen, vol. Ixiv. p. 342.

264- The Rev. Brice Bronwin on the Theory of the Tides.

cent, from one another in their amount of carbon, yet the
analysis of the whole bees'-wax gives results showing in differ-
ent specimens which I have examined, no difference of consti-
tution which analysis can reach. This renders it probable
that the action is definite, and that the sugar in all cases loses
the same amount of oxygen, although the remaining elements
may in different cases be differently grouped.

w

XXXIV. On the Theory of the Tides.
By the Rev. Brice Bronwin.

[Continued from p. 192.]
E are now prepared to find (w) ; for we have

^ = sin^fi -TY +2« sinficosfl -j- =S{2?? cos $A— (w- cv)/B}
OCT dt at

sin 6 sin /(<p — §).

Or, by neglecting the very small term containing (v), and then
eliminating B,

8 / dA\

~ =2(2 cos 6A — 2B)/i sin 9 sin i{f—^)=%\cos 9A — sin fl ^ )

n sin d sin /(f — §) = 2D sin i{f — S) suppose.

Integrating, observing that (p = ;i^ + 'nr— \|/, and ^-\-§=z a con-
stant, we have

—(ti=%< -Dcosi((p — S) V,

^^ — «j= -D2Cos2(<p — ^2) + DiCos((p — ^i)

. (9.)

where we neglect the arbitrary, because we take account only
of the terms containing <p.
When i=2,

But

(cos6A-sinfi^)sinS=-sin35-|(^-AJ.
V^°' 2 '°'2/

A 1/1

sin^

d / A

(s-i^fl) = ^^^"4/^—

V^^'l cos^lj

The Rev. Brice Bronwin on the Theory of the Tides, 265
-sin^ 9 4 (-A) = -S^2 sin^Z-

Hcos^^ j

= - 4«2 sin2- tan^ - (3 + cos 5).
When z=l,

(cos 5 A — sin Q -^ j sind= sin Q cosflA=«, sin d cos 5.

Therefore

T)^= -^^nttc^ sin^ - tan^ « (3 + cos 9), D^ = waj sin 5 cos fl.

These results have been obtained by substituting the values
of A from (8.); and it may be observed that all the functions
of (i9) are discontinuous at the equator, and only hold from the
pole to the equator. By suitably changing the arbitrages we
may now write,

=D2Cos2(!p — €2) + I^iCos(<p--^i)

A A'

Dci—a^ sin^ - tan^ « (^ "^ ^®^ ^)» -^i ~ ^i ^'*" ^ ^^^ ^*
If we make

(10.)

- =p=H-ecos(a— tt),

where («) is the mean distance, [e) the eccentricity, (2) the
longitude, and (tt) the long, of the apse of the planet ; and if
we also make

Eo= :: — 3 sin^ 9, E. = ^ sin 9 cos 5,
we have from (1.), retaining only the same terms as heretofore,

— = Egfi^ cos^ V cos 2(p 4- Eip^ sin v cos v cos f.
For these terms, therefore,

i/=

aV

or by substitution,

3/=(D2 cos 2^2+^2^^ cos^ v) cos 2<p + Dg sin 2^2 sin 2(p

+ (Dj cos §1 + Ejp3 sin v cos u) cos f + Dj sin ^1 sin f.

i/=F2Cos2(9-^2) + FiCos(^~^i); • • (n.)

Assume

^}.(12.)

266 The Rev. Brice Bronwin on the Theory of the Tides.

or

5^= Fg cos 2/82 cos 2(p + F2 sin 2j32 sin 2<p + F, cos /Sj cos f

+ Fi sin ^1 sin f.

This value of {y) (the height of the tide), compared with the
preceding, gives

F2Cos2/32=D2Cos2g2 + E^P^c^s^'^j F2 sin 2/82 -=D2sin2§2
Fj cosjSjzsDiCosSj + Ejp^sinvcost;, Fisin/3j = Disin§j.

From these equations we must determine F2» Fj, /Sg, and /3^.

In small seas it is very easy to see that the direct effect of
the force is very small compared with the horizontal velocities,
and therefore that we ought to have D2 much larger than Eg.
We shall proceed on this supposition. Therefore if /32 = §2 + '^>
A is a very small quantity, and we shall have

cos 2/82 = cos 2^2— 2 A sin 2^2' sin 2/32= sin 2g2 + 2Acos 2^2

nearly by Taylor's theorem. Multiply the first of (12.) by
the first of these, and the second by the second of these,
member by member, and add the products ; and we find

F2=D2 + E2p3cos2tJcos2g2; . . . (13.)
neglecting the small term

— 2E2Ap3 cos^v sin 2^25

which containsthe product of the two small quantities Egand A.
Dividing the second of (12.) by (13.), member by member,
there results

F
sin 2/32= s>" 2^2— rf p^cos^ v sin 2^2 cos 2^3
1^2
very nearly. If we put for sin 2/83 in this its value before

given, we find

A = — ^-j^ p^ cos'^ V sin 2^2»
and consequently

^2 = ^2- ^^P'cos^^ sin 2^2. . . . (H.)

We cannot positively say that Dj is large compared with
E, ; but if we add together the squares of the third and fourth
of (12.), we have

Fi2 = Di2 + 2D,Ejp'^ sin ?; cos v cos g, + EfpSin^ v cos^v.

Suppose

Fi = Di + Eip^ sin i;cosr;cos §1. . . . (15.)

The square of the second member of this will differ from the

The Rev. Brice Bronwin on the Theory of the Tides. 267

second member of the preceding only by the small quantity
Ej^p^' sin^ V cos^ v sin^ ^j. We cannot affirm that this is a very
near approximation ; and without more knowledge of the
comparative values of Dj and Ej, we cannot express /Sj as we
have done /Sj. Dividing the third of (12.) by the fourth, we
have

^ Q A. P , T^ osin vcosu ,, _ .

C0t^, = C0t^l+E,/j3— -j_^; . . . (16.)

whence it appears that /Sj may in some cases vary very cotisi"
derably.

Let (o) be the angle which the orbit of the planet makes
with the equator, (z) the longitude measured on it from their
intersection. Then (o) is the obliquity and {z) the true lon-
gitude for the sun, and they are nearly the same for the moon.
Also {z) is the hypothenuse, {v) the perpendicular, and (o)
the angle at the base of a right-angled spherical triangle ; and
(4/) is the base for the sun, and nearly so for the moon. Hence
by spherical trigonometry,

tan 4/= cos o tan z,
and therefore

rf\(/ dz d'h cos^vl;

~ cos 0 — 5- » -7- = cos o

cos-'^J/ cos^z dz cos^z

But

cos 5^= cost? cos tf/j
consequently

^4/ COSO . -ox

3- = — 5— = cos 0(1 + sm'' v)s
dz cos-* V ^ '

neglecting sin'^ v and higher powers. Also

sin v=- sin osmz;
therefore

-r- = COS 0(1+ sin^o sin^z)= cos of 1 + -sin^o— -sin^ocos2z j

, 1 • 2 ^

= 1 — - sm'' 0 cos 2z.

2

neglecting sin^o, &c.
But

vt + e = z—2es\x\{z — Tt)\
consequently

vdt = dz '- ^ed^ cos (^r — tt ),
neglecting e^, &c.

It may be doubtful whether we should express the value ot
^ in terms of the mean longitude or of the true ; I have chosen

268 The Rev. Brice Bronwin on the Theoi-y of the Tides.
the latter. By means of the above formulae we have

d^—cvdt—d^=dz\ c — 1 + ^sin^ocos2^r — 2^Ccos(2r — tt) >.

As (§) cannot contain a term increasing with z or ty we must
have c=l ; then

d^
and

=dz< — sin^ o cos 'iz—2e cos [z—ir) V,

§=^+ — sin^osin 2<3'— 2^sin (2"— tt). . . (17.)

Change [k) into [k^ and (^j), and we have the values of (§2)
and (^i). Whence by Taylor's theorem,

sin 2§2=sin 2 kct-\- - sin^o cos 2k^ sin 2z—^e cos2^2S'n('2'— "■)»

cos2^2~cos Ik^— ^sin^ o sin 2/^2 s^" ^^ + ^^ ^'" ^^2 ^'" (2— t)

nearly.

Putting for f its value in (13.) and (14.), and 1 — sin^t; for
cos^ V, and neglecting the very small terms containing e sin^ v,
we have

F2=D2 + E2 cos 2^2— E2 sin^ «>cos 2^2+ ^^£2 COS2I2 cos(2— tt),

E E 3^E

^2 = ^2- grf" ^^" ^^2"^ 20"^^"^ '^ ^^" ^^2- ^^sin2g2Cos(2-9r).

Substituting for §2 its value from (17.) in these, and neglecting
some very small quantities, we find, making to abridge.

K2=D2+E2C0S2X:2, G2 = ^''2~~o|f ^^'^^^2»

E
H2= 1 — jy cos 2^2»

F2= Kg— E2 cos 2^2 s'n^ iJ — — E2 sin^ 0 sin 2^2 sin 2^

+ S^EjCOs 2^:3 cos (^—tt) + ^^Eg sin 2^2 sin {z—it)

£ 1

182=62+ ^jl- sin 2A:2sin^w— - H2sin^osin22— 2^H2sin (z— w)

'2
3eEo

2D2

sin 2^2^08(5"— tt) (18.)

Since
sine sin 2«=2sinosin^cos«=2sin i;cos<2r=2 sin i;cos^|/

= L2+ ^ Eg sin^ 0 cos 2 (r|/ + ^2) + SeE^ cos (\I/— 2^2— '»")

The Rev. Brice Bronwin on the Theory of the lides, 269
nearly, these may be replaced by
F^= Kg— Ej cos 2^2 sin^ f — E2 sin o sin 2^3 sin sy cos 4/
+ 3^E2 cos 2^2 cos {z—ir) + 4^E2 sin 2^2 sin {z—v),

E 1

182= G2 + ir^ sin 2A-2 sin^ «'— o Hg sin o sin v cos rp

— QeJrlci sin (z — t) — 57^ si n 2^2 cos (2 — tt ) .
Or, if we please, since

sin^ 5y=sin^ o sin^ 2= tt sin^ » — ;;r sin^ 0 cos 2^,
2 2

Fg = 1.2 + - E2 sin^ 0 cos 2(« + ^2) + S^Eg cos {ss — 2^:2 — w)

nearly,

= L

nearly,

E 1

182= G2+ ^rl-s'" ^^2 s'n^ V— - Hg sin o sin v cos ^—^eU^
2U2 -^

sin (^I/— tt)

nearly by neglecting the last term, which is very small, as also
are some of those terms containing this quantity which have
been retained. In the above

L2= Kg— - E2 sin^ o cos 2^2= ^2 + ^3 cos o cos 2^2

Jd

nearly.

Making p= 1, and ^i = ^j, in the small terms, we may make

Fj = Dj + Ej cos ^, sin u cos t;.

But this will not be very near the truth unless Dj be some-
thing larger than Ej; and we cannot conveniently express /S^.
But if Dj be considerably larger than Ej, we have

sin jSj = sin ?j ( 1 — — cos ^1 sin v cos v \
nearly. Also

sin §1 = sin ^1+7 sin^ 0 cos k^ sin 23

nearly, neglecting the term containing e. Hence we easily
find

270 The Rev. Brice Bronwin on the Theory of the TideSt

E . . 1 .

sin /3,= sin Jcy— ^r- sin k^ cos k^ sin v cos v+ -sin^ocoskySmQ.z

E . 1 . .

= sin 7^1 — —■ sin ^i cos Jc^ sin u cos ?;+ - sin ocos^^ sini?cos\I/

nearly, and therefore

•p 1

/3] =k] — j^ sin Jci sin v cos u+ ^ sin o sin v cos \^
nearly.

We might find in the value of the terms D3Cos3(<p— §3)

and D4 cos ^((p — §4); the coefficients Dg and D4 being, as
before, functions of fl without / or 2 ; but these terms must be
very small.

From (1.) it is easy to see that there will also be terms of
the form

l+m sin^ o sin 2z+p sin^ 0 cos23r + qe sin [z—Trj + se cos (z—tt),
the coefficients /, m, &c. being functions of fl; but as they are
very small, we shall not attempt to determine them. If, how-
ever, we wish to make 8w a complete variation relative to such
terms, we must make the coefficient of Sw to vanish, or

sm'^ 9 — ^ +2« sm 9 cos 9^7 =0,
ar at

which will give an equation of condition. The arbitrary of
integration will now be a constant independent of 9. And we
shall have

8«j = a9(— 5 — 2wsm9cos9-^),

or

8w = S9r^( -5-2- — 2« sin 9 cos 6^1 —2nrh' sin^ d -j-,

according as we make dco a complete variation relative to Q
only (which, indeed, it is already) or relative to both Q and r.
The equation of continuity will become

• adu .

sm 0 -jT + cos 9 11=0,

or

dirh) Jdu A

as the case may be. I believe we must complete the variation
for both r and 9.

Gunthwaite Hall, near Barnsley, Yorkshire,
September 7, 1849.

[To be continued.]

Chloride of sodium 3'4t3~\
Potash .... 48-19
Soda 5-18 i>or<(

[ 271 ]

XXXV. On the Inorganic Constituents of Organic Bodies. By
H. Rose, Professor of Chemistry in the University of Berlin.

[Continued from p. 1870

Appendix IX.

Examination of the Inorganic Constituents of the Flesh of the
Horse. By M. Weber.

THE flesh consisted of the muscles of the fore-leg of a lean
horse, immediately after the animal was killed, and com-
pletely freed from blood by the injection of water into the
brachial artery until it escaped from the veins in a colour-
less state; it was then dried and carbonized.

The residue of the aqueous extract was perfectly free from
carbonic acid, and consisted of —

-NaCl . . 3-43

2KO + PO5 83-27

2NaO + P(>, 11-10

Phosphoric acid . 41-68

Sulphuric acid . . O-71J v~ 99-32

99-19
The muriatic extract consisted of —

Potash 26-47

Soda 4-36

Lime 6-02

Magnesia 12*20

Peroxide of iron . . . 3-96

Phosphoric acid . . . 46-99

100-00

Assuming that the phosphoric acid forms pyrophosphates
with the bases, we obtain the following calculated result: —

Bibasic phosphate of lime . . 13-64

Bibasic phosphate of magnesia 33*27

2Fe02 + 3P05 1'22

Bibasic phosphate of potash . 30«14

Potash 9-28

Soda 4-45

100-00

If, however, we admit that both the alkalies and the earths,
excluding the magnesia, form c>phosphates, we obtain the
following result: —

272 Prof. H. Rose on the Inorganic Constituents

Tribasic phosphate of potash
Tribasic phosphate of soda .
Tribasic phosphate of lime .
Bibasic phosphate of magnesia
Perphosphate of iron . . .

39-82

7-66

11-35

33-27

7-50

99-60

The amount of phosphoric acid required by calculation is
46-61 per cent.; that found by analysis amounts to 46-99 per
cent.

Residuary carbonized mass. — The ash of this consisted of—

Potash 36-64

Soda 4-71

Lime 1-88

Magnesia 4*36

Peroxide of iron . . . 0*76

Phosphoric acid . . . 51*65

100-00

The precipitate thrown down by ammonia from the muriatic
solution of this ash, after having been heated to redness,
consisted of 2CaO, PO5 + 2MgO, PO5 + Fe^ O3. The phos-
phoric acid required by this formula amounts to 9-87 per cent.;
analysis gave exactly this quantity. The remaining 41-79
per cent, of phosphoric acid were neither wholly combined
with the alkalies as pyrophosphates, nor as metaphosphates.
The phosphoric acid is too large in quantity for the former
case, and too small for the latter.

The relative amounts of ash in the flesh were as follows : —

Extracted by water 42-81

Extracted by muriatic acid 17*48

Ash of the remaining carbonaceous mass 39*71

100-00

The amount of the whole of the inorganic constituents of
the flesh was —

Chloride of sodum
Potash . .
Soda . .
Lime . . .
Magnesia
Peroxide of iron
Phosphoric acid
Sulphuric acid

1-47
39-95
4-86
1*80
3*88
1*00
46-74
0-30

Oxygen.

6-77-
1-24
0-50
1*50 I
0-30 J
26-19\
1-17J

100-00

10-31

26*36

of Organic Bodies. 273

The proportion of oxygen in the bases to that of the phos-
phoric acid was as 2 ; 5, i. e. the salts were pyrophosphates ;
and in this respect this ash has some analogy with that of
wheat, which, however, contains far more alkaline chlorides.

Thus water and muriatic acid principally exti'act alka-
line phosphates from carbonized flesh, and alkaline chlorides
and carbonates from carbonized blood. The muriatic extract
of the blood contains altogether so few constituents, that we
may suppose they are only those which had previonsly resisted
the solvent action of water, or were formed from the anoxidic
portion of the blood by the imperfect exclusion of the air
during its carbonization.

If so, and we admit that the alkaline chlorides and car-
bonates do not belong to those constituents of the blood, the
inorganic portions of which consist of phosphates in an oxidized
and unoxidized state, these constituents of the blood would
contain the phosphates in a perfectly deoxidized state. Such
are probably the proteine substances of the blood, which would
then differ from those of the flesh, by the former being anoxi-
dic and the latter meroxidic substances. Probably in future
we must only call those substances anoxidic, meroxidic, and
teleoxidic, the inorganic constituents of which consist princi-
pally of phosphates in a deoxidized, partly oxidized, and per-
fectly oxidized state. The blood will then be an anoxidic,
and the flesh a meroxidic substance.

Appendix X. and XI.

Analysis of the Ashes of Human Faces and Urine, By
M. Fleitmann.

Although a single analysis of the ash of the faeces, without
regard to the diet, can be of but little physiological importance,
inasmuch as it must depend greatly upon the nature of the
food consumed and upon the mode of life of the individual, yet
a comparative examination of the inorganic constituents of the
faeces and urine may afford us instructive conclusions regard-
ing the quantities excreted in the same period of time. Such
a comparison had not previously, I believe, been made, and as
we shall see, has yielded a remarkable result. For this purpose
the faeces and urine of a young man, aged 20, were carefully
collected during four days. During this period his diet was
very moderate, consisting principally of meat, and as little ve-
getable matter as possible. He drank no spirituous liquids,
and little liquid of any kind during the period, but he took
much corporeal exercise.

JFlrces.-- 'When dried at 212° F. they weighed only lO^'lO
grms. They were carbonized as usual.

Phil. Mas. S. 3. Vol. 35. No. 236. Oct. 18*9. T

274 Prof. H. Rose on the Inorganic Constituents

Aqueous extract. — On evaporation to dryness it left a residue
of r 93 3 grm., consisting of —

Chloride of sodium .
Chloride of potassium
Potash ....
Hydrate of potash
Phosphoric acid .
Sulphuric acid
Silica ....
Carbonic acid . .

3-15
0-37

27-81
54--18
6-75
1-57
0-52
5-65

lOO'OO

The large amount of hydrate of potash was produced by
the action of the carbon upon the alkaline carbonate. These
constituents correspond to the following salts: —

Chloride of sodium . . .
Chloride of potassium . .
Tribasic phosphate of potash
Sulphate of potash . . .
Silicate of potash ....
Carbonate of potash . . .
Hydrate of potash . . .

3-15

0-37

20-13

3-41

1-05

17-71

54.-18

100-00

Muriatic extract.-^Th'xs left 6-493 grms. of residue, con-
sisting of —

Potash . . .
Soda ....
Lime . . .

Magnesia
Phosphoric acid
Sulphuric acid
Silica . . .
Peroxide of iron

10-22

1-06

31-32

13-98

41-69

0-18

0-23

1-32

100-00

3CaO+P05 56-98

3KO + PO5 15-38

3NaO + P05 1-87

3MgO + P05 18-30

r) CaO, SO3 . 0-31

CaO, SiOg . 0-36

MgO / . 5-48

^FcgOg . . 1-32

100-00

The magnesia must have existed in the carbonized mass in
the form of carbonate.

liesidua?y carbonaceous mass. — This was considerable, and
consisted principally of sand, part of which existed as such in
the faeces, and even in the food ; part must have been swal-
lowed in the form of dust during the exercise taken by the
subject of the experiment in the fields near Berlin. The
residue weighed 1-996 grm., and consisted of —

of Organic Bodies.

275

Potash . , .
Soda ....
Lime ....
Magnesia . .
Peroxide of iron
Phosphoric acid
Sulphuric acid .
Silica . . .
Sand ....

4'83->|

^SKO + POs

7-25

0-42

3NaO + PO,

0-77

9-66

3CaO + P05

12-78

10'24

3MgO + P05

20*66

6-61

^or<^

CaO, SO3 .

6-45

19'61

MgO . .

0-62

3-77

Fe^Og . .

6*61

6*25

SiOg. . .

6-25

38-6lJ

LSand . . .

38-61

100-00

100-00

Hence the phosphates of the excrements are c-phosphates,
and the bases are all in the proportion of three atoms to one
of phosphoric acid. In the aqueous extract, the greater part
of the potash is either combined with carbonic acid, or exists
in the form of potash ; whilst in the excrements themselves,
the alkali was combined with an organic substance, which
occupied the place of an acid. Since the faeces principally
carry off those oxidized salts which are insoluble in water,
whilst the urine removes those which are soluble in water,
most of the inorganic constituents of the faeces are contained
in the muriatic extract of the carbonized mass. The large
quantity of phosphate of magnesia in this ash is remarkable.

The excrements might be regarded as teleoxidic substances;
at least the unoxidized inorganic matters existing in them are
so small, that they probably arise merely from the undigested
remains of the food. The small quantity of soda present,
compared with that of the potash, is also remarkable ; espe-
cially as the bile principally contains soda, and but little pot-
ash. Hence the soda of the bile must be removed by the
urine, not the faeces. The following are the inorganic con-
stituents of the faeces as obtained by the three operations :-

Chloride of potassium 0-07"^
Chloride of sodium . 0*58
Potash 12-4-4

Hydrate of potash

Soda

Lime . . . .

Magnesia . .
Peroxide of iron
Phosphoric acid
Sulphuric add
Silica . . ,
Carbonic acid .
Sand ....

10-05
0-75

21-36

10-67
2-09

30-98
1-13
1-44
1-05
7-39.

10-000
T2

)>ov<

■KCl . . .

0-07

NaCl . . .

0-58

3KO + PO5 .

14-70

SNaO+POg.

1-32

SCaO + POs.

37-95

3MgO + P05

15-36

KO, SO3 . .

0-63

KCSiOg. .

0-20

CaO, SO3 .

1-43

CaO, SiOg .

0-23

KO, CO2. .

3-28

KO, HO . .

10-05

Fe^Og, SiOg?

3-28

MgO . - .

3-53

Sand . . .

7-39

100-00

276 Prof. H. Rose on the Inm-ganic Constituents

Examination of the Urine. — As the residue of the evaporated
urine was very difficult to dry at 212° F., it was carbonized
at once.

Aqueous extract. — This contained by far the greater part of
the inorganic constituents of the urine. In the urine excreted
during four days, it amounted to no less than S^'l^S grms.
These consisted of —

Chloride of sodium . 62*78"

Chloride of potassium 9*89

Potash 15-40

Magnesia .... 0'32

Phosphoric acid . . 8*92

Sulphuric acid . . 2*69

lOO'OO.

^NaCl . .
KCl . .

KG, SOg .

^or of<i 2KO+PO5
3KO4-PO5
2MgO+PO.

62-78
9-89
5-87

16-12
4-55
0-42

SMgO + POs 037
100-00

Muriatic extract. — It amounted to 5*085 grms., and con-
sisted of —

Soda

19-22"^

Potash . . . .

2-96

Lime . . . .

17-66

Magnesia . . .
Phosphoric acid .

13-65
41-51

>or of<

Sulphuric acid

1-86

Silica . . . .

2-76

Peroxide of iron

0-38

3NaO+P05

33-83

3KO + PO,

4-45

SCaO + POg

29-99

3MgO + P05

21-98

CaO, SO3 .

3-18

MgO, SiOg .

6-19

Fe^Og . .

0-38

100-00

100-00

Residuary carbonaceous mass. — This left a very small quan-
tity of ash on incineration, only 0-352 grm., the principal
component of which was silica, weighing 0-156 grm.; the
remainder consisted almost entirely of phosphate of magnesia.
It has been suggested above, that this small quantity of inor-
ganic constituents existed in the urine in a perfectly oxidized
state, and had resisted the solvent action of the muriatic acid,
probably because the magnesia had formed with the silica a
compound insoluble in dilute muriatic acid.

If this view be adopted, all the inorganic constituents exist
in the urine in a perfectly oxidized state; hence it is a per-
fectly teleoxidic substance.

The following are therefore the inorganic constituents of
the carbonized mass of the evaporated urine : —

of Organic Bodies. 277

Chloride of sodium 5703

Chloride of potassium 8*99

Tribasic phosphate of soda .... 2*90

Tribasic phosphate of potash . . . 4'53

Bibasic phosphate of potash .... 4*65

Tribasic phosphate of lime .... 2*57

Tribasic phosphate of magnesia . . 2*57

Bibasic phosphate of magnesia . . . 037

Sulphate of potash 5*33

Sulphate of lime 027

Magnesia, peroxide of iron, and silica 0*79

100-00

These inorganic constituents must not be compared with
those existing in the urine before carbonization. In the latter
the bases are partly combined with organic acids, which are
converted into carbonates during the process of carbonization,
the carbonic acid of which is expelled by the phosphoric acid
of the bibasic phosphates. Thus tribasic phosphates are
formed, which cannot exist as such in the urine, because the
latter exerts an acid reaction.

During the four days in which the faeces and urine were
collected, the inorganic constituents of the former amounted
to 10'4;22 grms., and the latter to 59'585. This remarkable
result would not have been expected a priori. The difference
becomes still more striking when the amount of the sand is
deducted from the inorganic constituents of the faeces, and
which can only be regarded as an accidental mixture.

The following comparison exhibits the inorganic compo-
nents of the faeces and urine excreted in a day, excluding the

sand : —

Urine. Faeces.

Chloride of sodium 8-9243 grms. 0'0167 grms.

Chloride of potassium 0'7511 ...

Soda 00185 ...

Potash 2-4823 ... 0-5'i-55 ...

Lime 0*2245 ... 05566 ...

Magnesia .... 0-2415 ... 02781 ...

Peroxide of iron . . 00048 ... 0 0544 ...

Phosphoric acid . . 1-7598 ... 0*8072 ...

Sulphuric acid . . 0*3864 ... 00293 ...

Silica 0-0691 ... 0-0375 ...

14-8438 2-3438

Hence the amount of inorganic constituents in the urine is
more than Q^ times greater than that in the solid excrements.

278 Prof. H. Rose on the Inorganic Constituents

The following are the weights of the inorganic constituents
obtained in the different parts of the examination of the faeces
and the urine : —

Faeces. Urine.

Extracted by water 18-55 90-87

Extracted by muriatic acid 62-30 8-54<

In the ash of the residuary carbonized mass 19-15 0'59

100-00 100-00

Appendix XII.

Examination of the Inorganic Constituents of the Bile {of
Oxen). By M. Weidenbusch.

Aqueous extract of the carbonized mass. — This, when evapo
rated to dryness, consisted of —

Chloride of sodium 28-77-| rNa CI

Potash . . .
Soda ....
Phosphoric acid
Sulphuric acid .
Carbonic acid .
Silica ....

4-51
35-79

8-55

4-81
11-70

0-26J

94-39

SNaO+POg
3KO + PO5
;>or of<; NaO, SO3
NaO, CO2
NaO, HO
LSi O. . .

Muriatic extract. — This consisted of —

Potash 3-70

Soda lJ-50

Lime 27-00

Magnesia ....
Peroxide of iron . .
Manganoso-manga-"\
nic oxide . . j
Phosphoric acid . .
Silica

7-41
4-21

2-11

41-63
2-41-

99-97

>or of<

^SKO + PO^
SNaO + POs
SCaO+POs
SMgO + POg
MgO . .

F.O3 . .
MnO, Mug O3
iSiO, . .

28-77
14-51
6-78
8-55
28-27
9-34
0-26

96-48

20-25
49-81
14-71
0-69
4-20
2-11
2-41

100-00

Residuary carbonaceous mass. — The ash consisted of —

Potash . .
Soda . . .
Lime . . .
Magnesia . .
Peroxide of iron
Phosphoric acid
Sulphuric acid

6-71
40-49
2-45
4-01
0-80
3-89
41-63

99-98

of Organic Bodies. 279

The sulphur may be considered as existing in the carbo-
nized bile, after exhaustion by the solvents, as a constituent
of certain compound radicals, in the same manner as was
assumed to be the case with the phosphorus in the carbonized
product of other organic substances. But in this carbonized
mass the amount of sulphur is much larger than would be
found by calculation from that of the sulphuric acid obtained.
A very large portion of it is volatilized during the oxidation.
If the exhausted carbonized mass be mixed with nitrate of
baryta, and the mixture be heated to redness, so much sul-
phate of baryta is obtained, that the quantity of sulphuric
acid existing in it amounts to 30 per cent, more than that
obtained by the mere oxidation of the carbonized mass.

The following are the proportions of the inorganic compo-
nents of the bile as obtained in the three operations: —

Extracted by water 90*85

Extracted by muriatic acid ^-QS

In the ash of the residue of the carbonaceous mass 4*22

10000

The following are the whole of the inorganic constituents
of the bile of the ox: —

Oxygen,

Chloride of potassium . . . 27'70

Potash . . , 4.-80 0-81

Soda . 36-73 9*39

Lime 1-43 0-40

Magnesia 0-53 0*20

Peroxide of iron 0*23 0-07

Manganoso-manganic oxide . 0*12 0'03.

Phosphoric acid 10-45 5-85 "^

Sulphuric acid 639 3'82

Carbonic acid 11*26 8*14

Silica 0-36 0*18

>10'90

^17-99

100-00

The quantities of the acids are not correct, because, as we
have stated, a far larger amount of sulphuric acid would have
been obtained had the whole of the sulphur been converted
into sulphuric acid.

Appendix XIII.

Exami7iation of the Inorganic Constituents of Cow's Milk. By
M. Weber.

The cows from which the milk was procured were fed with
the refuse of a brewery in addition to the ordinary stall-fodder.

280 Prof. H. Rose on the Inorganic Constituents

The milk was not skimmed, but evaporated at once and car-
bonized.

Aqueous extract. — The washing required to be continued
for an extraordinary length of time. The residue of the eva-
porated extract consisted of —

Chloride of potassium 4r42

Chloride of sodium . 13*85

Potash 29-66 y

Phosphoric acid . . 7*25
Sulphuric acid . . . 0'17
Carbonic acid . . . 7*27

or

or

fKCl. . .

41-42

NaCl . .

13-85

3KO + PO5

21-60

KO, SO3 .

0-36

K0,C02 .

22-83

100-06

99-62

Muriatic extract. — No evolution of carbonic acid could be
perceived on the addition of the muriatic acid. The consti-
tuents were —

Potash ....

. 6-29

Soda

. 12-19

Lime

. 36-70

Magnesia . . .

. 3-26

Peroxide of iron .

0-30

Phosphoric acid .

. 41-26

100-00

Hence the muriatic acid had only dissolved phosphates.
Residuary carbonaceous mass. — It yielded —

Potash . . ... 33-13

Soda 9-01

Lime 16-58

Magnesia .... 3-40

Peroxide of iron . . 1-10

Phosphoric acid . . 36-60

Silica 0-18

100-00

Thus the anoxidic portion of the milk, after oxidation, was

of the same composition as the teleoxidic.

The followinix are the results of the examination of the
o

milk: —

Extracted by water 34-17

Extracted by muriatic acid 31-75

Ash of the remaining carbonaceous mass . . . 34-08

10000

of Organic Bodies. 281

The whole of the constituents were —

Oxygen.
Chloride of potassium . . . H'lS
Chloride of sodium .... 4)*74;

Potash 23-4.6 3-971

Soda 6-96 1-78

Lime 17-34 4.-87 i>ll-51

Magnesia 2-20 085

Peroxide of iron 0'4;7 0-14J

Phosphoric acid 28-04 15*71'

Sulphuric acid 005 002

Carbonic acid 2-50 1-80

Silica 0-06 0-03.

100-00

M7-51

Hence the phosphoric acid of the bases is to that of the
acids nearly as 3 : 5. The teleoxidic portion of the milk con-
tains c-phosphates, and the anoxidic portion yields by oxida-
tion c-phosphates also.

Thus milk is a meroxidic substance. We might almost call
it a hemioxidic substance, if the large quantity of the alkaline
chlorides contained in the aqueous extract were excluded from
the teleoxidic portion, to which they evidently do not belong.

The large amount of phosphoric acid in the teleoxidic por-
tion, and the considerable quantity which the anoxidic portion
yields on oxidation, are remarkable. It is hence evident, as
has frequently been remarked, how well the milk is adapted
for effecting the ossification of the bones in the mammalia.

Whilst in the blood the bases predominate over the acids,
in the flesh we find little else than pyrophosphates, and in the
milk the bases for the most part form c-phosphates.

Appendix XIV. and XV.

Examihatioti of the Inorganic Constituents of the M^ite and
Yolk of Hen's Eggs. By M. Poleck.

These experiments were among the first made by the method
of carbonization, and were instituted before the process was
perfected ; they do not therefore deserve too much confidence,
although performed with great care. But as they appeared
to me of some importance, I shall briefly describe them.

The principal source of error consists in the fact, that in
some of the analyses the alkali contained in the muriatic ex-
tract, not having been suspected to exist there, was over-
looked ; moreover, the exhausted carbonized mass being

282 Prof. H. Rose on ike Inorganic Constituents

burnt in an atmosphere of oxygen, would allow of the volatili-
zation of a considerable portion of the alkaline phosphates.
The separation of the white from the yolk can be easily
effected, by well boiling the eggs in water until they become
hard.

The relative proportion of the white and yolk was not ex-
actly the same in all the eggs. The following results were
obtained in regard to this point : —

Four eggs yielded
Sixteen eggs yielded .
Fourteen eggs yielded

60*60 per cent, white
39-40 ... yolk
5S'V6 ... white
4.1-57

59-42
40-58

yolk

white

yolk.

White of egg, — It yielded in two instances —

or

Chloride of potassium
Chloi'ide of sodium

Soda

Sulphuric acid . .
Carbonic acid . .
Silica

I.

47-19
10-66
24-22

1-61
14-66

0-17

100-08

11.
51-33
17-13
17-71
1-67
10-49

98-51

98-53

Chloride of potassium .

. 47-19

51-33

Chloride of sodium

. 10-66

17-13

Carbonate of soda . .

. 39-23

28-01

Sulphate of soda . .

2-83

2-96

Silica

. 0-17

99-43

In both analyses a little more carbonic acid was found than
could be combined with the alkali. This is remarkable;
because in the aqueous extracts of the carbonized mass of
other organic substances, considerably less carbonic acid was
frequently found than was requisite for the saturation of the
alkali, a considerable portion of the carbonic acid being fre-
quently reduced to carbonic oxide by the carbon.

Muriatic extract. — As in the first experiment, the presence
of the alkalies was overlooked ; the result of the second only
is given : —

of Organic Bodies. 283

Potash 4-95

Soda 913

Lime 1053

Magnesia 11 '6 1

Carbonate of lime . . 11 'l^

Carbonate of magnesia . 15"48

Peroxide of iron . . . 2*75

Phosphoric acid . . . 23*85

Silica 10-56

10000

Residuaty carbonaceous mass. — It was not incinerated with
platinum, but in oxygen gas ; hence there was a loss. I have
already remarked that the proteine substances of vegetables
and animals alone appear to be meroxidic bodies ; all others
appear to be of a teleoxidic nature. The white of hen's eggs,
however, forms a remarkable exception to all the other pro-
teine substances which have been examined, in consequence
of the very small quantity of anoxidic substance which it
contains. The amount of ash is very small. In both experi-
ments the charred mass contained silica in the form of sand,
which, however, was deducted from the ash. The following
was the composition of the two ashes : —

I. II.

Potash ...... 11-93 16-76

Soda 10-83 5-48

Lime 12-21 821

Magnesia 24-15 9-02

Peroxide of iron . . . 1-41 5*64

Phosphoric acid . . . 30*73 37*24

Silica 8-71 17-63

99-94 99-98

These results differ very considerably; the cause must be
determined by future experiments.

On arranging the constituents in the form of salts, we find
in the first experiment i-phosphoric acid and some very basic
silicates ; in the second only i-phosphoric acid and less basic
silicates.

The quantities obtained were —

I. II.

Extracted by water 81-52 82-19

Extracted by muriatic acid .... 14-33 15-52

In the ash of the remaining mass . . 4*15 2-29

10000 100-00

284 Prof. H. Rose on the Inorganic Constituents

The components of the subject of the second analysis, as
obtained in the three operations, were —

Chloride of potassium . 2567

Chloride of sodium . . 8*57

Potash 5-4.3

Soda 12-49

Lime 6-25

Magnesia 7-03

Peroxide of iron . . . 2-09

Phosphoric acid . . . 15'28

Sulphuric acid . . . 0-84'

Carbonic acid .... 90 1

Silica 7-05

99-71

In accordance with these investigations, the white of hen's
eggs, although decidedly a proteine substance, must be enu-
merated amongst the almost teleoxidic substances. The large
quantity of silica in the white of egg, both in the teleoxidic and
the anoxidic portion, is remarkable. The white of birds' eggs
is equally as requisite for the formation of the feathers, which,
according to recent investigations, contain a large amount of
silica, as the milk of the mammalia is for the production of
the bones.

Yolk of Egg.

Aqueous extract. — It exerted a strongly acid reaction upon
litmus paper, and contained a considerable quantity of the
earthy phosphates in solution, which were not on this occasion
separated, but added to the muriatic extract. The dry mass
fused into a transparent vitreous mass at a low red heat. It
consisted of —

I. 11.

Potash 10-38 9*77

Soda 5-62 7-65

Lime 11-72 11*80

Magnesia l-4;5 2-04)

Peroxide of iron . . . 0-59 0-95

Phosphoric acid (undetermined) 68-74

100-95

The phosphoric acid formed metaphosphates with the bases,
excepting with the peroxide of iron. In the extract itself, they
did not exist in this form, but in that of acid 6-phosphates,
for it strongly reddened litmus paper; they were, however,
contained in that state in the solution of the fused residue of

of Organic Bodies, 285

the evaporated mass. In accordance with the second expe-
riment, we obtain the following arrangement for the salts : —

Monobasic phosphate of potash . 2^'51

Monobasic phosphate of soda . . 25*16

Monobasic phosphate of lime . . 41*73

Monobasic phosphate of magnesia 908

Perphosphate of iron .... 1*79

102-33

The calculated amount of phosphoric acid is 70*18 per
cent. ; experiment gave 68*74 per cent.

Muriatic extract. — The following is the composition of that
of the second experiment : —

Lime 22*32

Magnesia' . . . . , 2*98

Peroxide of iron ... 3*71

Phosphoric acid . . . 70*97

99*98

These salts are also metaphosphates, the iron compound
probably being excepted. They correspond to —

Monobasic phosphate of lime . . 78*94
Monobasic phosphate of magnesia . 13*30
2Fe2 03, 3PO5 '. 8*66

100'90

The calculated amount of phosphoric acid would be 71*89
per cent. ; that found was 70*97 per cent.

Jfesiduaty carbonaceous mass. — This, like the white of egg,
was also burnt in oxygen gas. Hence the results obtained in
the two experiments differ; in the first much less ash was
found than in the second. The latter consisted of —

Potash 7*96

Soda 6*75

Lime 1304

Magnesia 2*04

Peroxide of iron . . . 099

Phosphoric acid . . . 64*13

Silica 2*76

97*67

These are also mostly metaphosphates; only a very small
quantity of the bases can be combined with pyrophosphoric
acid.

286 Prof. H. Rose on the Inorganic Constituents
The following are the results of the experiments :-

Extracted by water from thel ,.o.»7a

carbonized yolk • • • J
Extracted by muriatic acid . 13' 73
Ash of the remaining mass . 22-54<

II.

40-95

8-05
51-00

100-00 100-00

These results differ very considerably, yet they show that
the yolk undoubtedly belongs to the meroxidic substances.

The inorganic constituents of the entire mass of the carbo-
nized yolk in the second experiment were —

Potash . . .
Soda ....
Lime . . .
Magnesia . .
Peroxide of iron
Silica ....
Phosphoric acid

5-94
4-82

15-79
2-36
1-85
0-92

68-26

99-94

These are metaphosphates. The yolk of egg contains more
phosphoric acid than any other organic substance treated of
in this memoir.

Inorganic Constituents of Yeast {from Berli?i Pale Beer).
By B. W. Bull ofNe-co York.

The yeast was washed with distilled water; the washing
cannot however be perfectly effected, because the pores of the
filter become so readily stopped up.

Aqueous extract. — This did not affect litmus paper ; during
evaporation it deposited earthy phosphates, which were added
to the muriatic extract. It consisted of —

Chloride of sodium
Potash ....

Soda

Phosphoric acid

0-69^
45-79 I pj

0-29 r' «^^

52-22J

fNaCl .. .
2KO+PO5
KO4-PO5 .
2NaO + P05

98-99

0-69

40-18

57-55

0-52

98-94

Hence the aqueous extract consisted essentially of a- and b-
phosphate of potash.

of Organic Bodies.
Muriatic extract. — It was composed of-

287

Potash ....

. 33-48

Soda ....

. 0-39

Lime ....

. 9-69

Magnesia . . .

. 4-79

Peroxide of iron .

. 0-52

Sulphuric acid

. 0-20

Phosphoric acid .

. 50-93

100-00
Part of the phosphoric acid is combined with the bases in
the form of b- and part in that of a-phosphates. It is not
easy to explain why these are not extracted from the carbo-
nized mass with the other a-phosphates by water. The cal-
culated salts are —

Bibasic phosphate of potash .
Monobasic phosphate of potash
Monobasic phosphate of soda .
Bibasic phosphate of lime . .
Bibasic phosphate of magnesia
Perphosphate of iron . . .
Sulphate of potash ....

50-39\ POg
11-40JKO

1-28
22-04
13-09

1-46

0-44

28-56
33-23

100-10

Residuary carbonized mass. — This consisted of —
Potash 28-71

Soda . . .
Lime . . .
Magnesia . .
Peroxide of iron
Phosphoric acid

0-60
2-35
6'SQ
1-16
60-82

100-00

or

{

KO

43-43
28-71

Monobasic piiosphate of potash . 72-14

Monobasic phosphate of soda . . 1-97

Bibasic phosphate of magnesia . 13-91

Monobasic phosphate of magnesia 5-18

Phosphate of lime (8CaO, 3P O5) 4-60

Perphosphate of iron 2*20

100-00

The phosphate of lime is in this case assumed as having
the same composition as that precipitated from the muriatic
solution by ammonia.

288 On the DevelopjnentqfEledricityby Muscular Contraction.

The entire results of the experiments were —

Extracted by water 27*24<

Extracted by muriatic acid 37" 70

In the ash of the residuary carbonaceous mass 35"06

The whole constituents were — 10000

Chloride of sodium . 0-19

Potash 35-16

Soda 0-4.2

Lime 4-47

Magnesia .... 4-05

Peroxide of iron . . 0-61

Sulphuric acid . . . 0-08

Phosphoric acid . . 54-74

99-72

These results agree very well with those obtained by Mit-
scherlich.

Yeast is therefore a meroxidic substance, and possesses most
analogy with flesh in regard to its inorganic constituents.

XXXVI. Notice respecting Du Bois Reymond's Discovery of
the Development of Electricity by Muscular Contraction.
By Prof. Buff of Giessen"^.

THE remarkable observation made by Du Bois Reymond,
that an electric current can be excited by muscular con-
traction, has been called in question by Messrs. Despretz and
Becquerel, who did not succeed in obtaining favourable results
on repeating the experiment f. Under these circumstances it
may prove of interest to describe a few experiments which I
have made with a better result.

The galvanometer employed was constructed by Kleiner of
Berlin ; it had 3000 convolutions of a copper wire one-fifth of a
millimetre in thickness. The extremities of this wire were
connected, according to Du Bois Reymond's directions, with
strips of platina cut out of the same sheet of metal. Each
strip dipped permanently into a vessel containing a saturated
solution of common salt. Notwithstanding this precaution it
was found impossible to obtain an absolute and permanent
uniformity of the two strips. However, on immersing the
fingers in the salt water, in general only a faint current, which

* From Liebig's Annalen der Chimie for June 1849.

•f A notice of M. Du Bois Reymond's experiments appeared in the Phi-
losophical Magazine for July 1849, p. 543; Messrs, Becquerel and Des-
pretz's observations on the same subject will be found at pp. 53, 55 of the
present volume.— Ed. P/iil. Mag.

M. Matteucci on the Voltaic Arc, 289

soon decreased, was developed ; but it was of such extent
that the needle seldom came to perfect rest. By bracing the
muscles of the hand and arm only doubtful effects were ob-
tained, precisely as was found by the French experimenters.
As the needle oscillated somewhat rapid!}', seven to eight
seconds to one oscillation, I endeavoured to render its astatic
system more perfect, and succeeded in reducing the time of
vibration to thirty seconds, /. e. in increasing the sensitiveness
of the needle nearly sixteen times.

Nevertheless the influence of the muscular contraction was
scarcely rendered more perceptible. Sometimes it was more,
sometimes less obscured by accidental deflections of the
needle, which it becomes the less possible to control the more
the magnetic directive force has decreased. Very little was
therefore to be expected from continuing to perfect the astatic
system, at least with the multiplier in use, the wire of which
did not appear to be entirely free from iron. Du Bois Rey-
mond obtained a higher degree of sensitiveness by means of a
larger number of convolutions, which is evidently preferable
in experiments of this nature.

One method of observing the phaenomenon discovered by
Du Bois Reymond with less sensitive instruments, is by in-
creasing the electromotive action excited by muscular exer-
tion. Sixteen persons who took part in this experiment held
each other's moistened hands, and on all contracting simultane-
ously the right, or simultaneously the left arm, they formed, as
it were, a circuit of increased electromotive power. The effect
on the needle was now perfectly evident, and opposite accord-
ing as the right or left arm was contracted ; the direction of
the current was always from the hand to the shoulder. It is
essential that the muscular contraction should be increased,
or at least continued, until the needle begins to return, and
then suddenly discontinued. Although it was found impos-
sible to produce a greater deflection than 10° to 12°, the cor-
responding intensity of the current was sufficient to overcome
any accidental influences; nay, even to stop a movement in
the opposite direction and to reverse it.
Giessen, July 13, 1849.

XXXVII. Observations on the Voltaic Arc.
By M. Matteucci *.

I HAVE studied the calorific and luminous phaenomena of
the voltaic arc, and the transference of matter, with the
aid of the electro-magnetic machine which is now generally
* From the Comptes Rendus for September 3, 1849.

Phil, Mag, S. 3. Vol. 35. No. 236. Oct. 1849. U

290 M. Matteucci 07i the Voltaic Arc.

employed in the application of electricity for medical purposes.
With this instrument, which acts for several days with a few
of Bunsen's or Grove's cells, there is between a point and a
slip of platina a continual series of electric sparks correspond-
ing to the very close interruptions of the circuit. On obser-
ving the phaenomenon with the naked eye, the arc of light
would be thought to be continuous; but by looking upon a disc
the surface of which is painted with black and bright rays,
rotating with a certain velocity, it is eas}' to be convinced of
the discontinuity of this electric light.

In all my experiments I employed two similar points of
platina, or of another metal, instead of a point and the plate
as extremities between which the spark should be emitted.

I first examined the temperature of the two metallic points
at the moment the electric arc was produced ; and for this
purpose made very near to the extremities of the points a hole
which was scarcely one millimetre in diameter, and into which
was inserted the point of a thermo-electrical clasp of iron and
copper in communication with the galvanometer. When the
experiment is carefully performed, so as to have a continuous
series of sparks accompanied by a constant sound, there is also
a fixed deflection of the galvanometer. I have in this manner
proved and measured the difference of temperature of the
positive point compared with that of the negative point, the
latter being always lower. The difference varies with the
metals, as was to be expected ; I found it greatest with iron
and copper, iron and platina, and less with lead, bismuth and
zinc.

I then studied the luminous phasnomena of this electric arc,
which in this case was of importance, as Dr. Neef of Frankfort
had never observed any light except at the negative pole.
According to that author, with a very weak current there is
constantly and only at the negative pole an electric light,
which he calls ■primary^ from its being, in his opinion, inde-
pendent of the presence of the matter of the poles.

I made a long investigation of the voltaic arc obtained with
the electro-magnetic machine, observing it with the aid of
a microscope which magnified from 40 to 60 times. The
experiment, which is very beautiful and important, succeeds
best on employing iron or platina points and a very feeble
current. The following are the phsenomena which I constantly
observed : —

1. The positive extremity is distinctly seen only in the state
of incandescence ; globules of red molten matter roll Over its
surface, which separate from it, leaving cavities, and are pro-
jected on to the negativepoint, where they form mushroom-like

M. Matteucci on the Voltaic Arc. 291

excrescences. By compelling the two iron points to remain in
contact, it is very beautiful to observe the formation in the
centre of a double cone of incandescent lava of a very brilliant
light ; and which, resting by its bases upon the two metallic
points, avidently flows from the positive to the negative pole.

2. A diffuse light is perceived similar to a flame or lu-
minous cloud, but transparent, enveloping the two points;
this light varies in colour with the nature of the metals, and
resembles every other electric light produced between differ-
ent metallic points. Thus it is green with copper, of a dirty
yellow with zinc, and violet with platina and silver.

3. This light or flame is constantly traversed by sparkling
points, similar to those which are produced by hammering
hot iron : these sparks are principally produced with the iron
points, and are always seen to glow outside of the electric
flame.

4. Lastly, some very brilliant and mobile luminous par-
ticles, and which seem always to congregate towards the ex-
tremity of the point, appear constantly and only at the nega-
tive pole. The observation of Dr. Neef is, as regards this,
perfectly accurate : it is requisite only to change the direction
of the current to observe this light immediately spring from
one pole to the other. If there is a drop of oil between the
points, the light of the negative pole is concentrated at the
extremity only, just as with an exceedingly weak current. If
a somewhat powerful current be employed, the phaenomena
described are no longer seen distinctly, and the two poles then
appear to be equally luminous.

I have likewise studied the transference of matter by the
spark between the two metallic extremities, and employed for
this purpose a plate and a point of similar or dissimilar metals,
making the plate sometimes positive and sometimes negative.
I examined only the plate with the microscope after the
experiment ; in every case there was a transference of the
positive on to the negative metal, and vice versa. The circular
stain which is forlned upon the plate is composed of the cen-
tral part, where signs of fusion are apparent, and where the
metal transferred from the other pole is deposited ; around
this central portion there is a radiating circle of a more or less
dark colour, which varies with the nature of the inetals.
When the plate is positive, the marks of fusion are greater,
and the stains of the metal transferred from the negative pole
are scarcely perceptible, whilst the border, of a dark colour, is
very lai*ge. The reverse occurs when the plate is negative.
When a drop of gum-water or of turpentine is interposed
between the point and the plate, it soon becomes charged with

U2

292 M. Matteucci on the Voltaic Arc.

a black powder consisting of finely divided metal, and the
mark formed on the plate has no border.

My principal object in making these researches being the
examination of the production of light at the negative pole, in
order not to have recourse to the hypothesis entertained on
this subject of the light being produced by one pole and the
heat by the other, I made a large number of experiments with
the positive and negative points of two different metals. I
found that the fixed light at the negative pole is never pro-
duced without the presence of a platina point at the positive
pole, and in this case the nature of the metal of the negative
point is indifferent; on the contrary, if the negative point is of
platina, and the positive pole is terminated by points of iron,
copper, zinc or silver, the fixed light no longer exists on the
negative point, or at all events the phaenomenon becomes much
confused. I was thus led to suppose that the phaenomenon,
being dependent on the nature of the metals, and produced
principally with platina, was owing to the positive pole be-
coming more heated, and to the particles detached from this
pole and transferred to the negative pole, becoming incandes-
cent from their very small size. It is evident that with metals
which readily oxidize and burn in the air, these phsenomena
are no longer produced in the same manner as with platina.

There still remained to ascertain the cause of this unequal
heating of the substance of the two poles. The voltaic arc
which I studied is produced in a circuit which is sometimes
formed by the contact of the two points, and at other times
imperfectly established by the transference of matter with the
spaik. I passed an electric current produced by a constant
battery through two cylindrical rods of iron or lead, which
were in contact at their bases. Each of these rods had near
its base a very small hole, into which was inserted a thermo-
electrical clasp communicating with the galvanometer. I
was thus able to measure the temperature developed by the
passage of the current in the metallic rod near the place of
interruption, or, more exactly, near the ends of the two rods
in contact. With this arrangement I was easily able to con-
vince myself that the temperature developed by the passage of
the current was at its maximum near the place of interrup-
tion; and that in order to cause this temperature to vary, it
sufficed to alter the reciprocal pressure of the two rods. In
proportion as the pressure decreased, without any perceptible
alteration in the electric current, the temperature of the rods
constantly rose. Thus the thermo-electric current developed
by the clasp, being from ten to fifteen degrees when the two
rods were pressed hard one against the other, rose from sixty

Notices respecting New Books. 293

to seventy degrees when this pressure was diminished. In like
manner the disengagement of heat varies considerably when
the surface of the bases of the rods in contact is either oxidized,
polished, or covered with a very thin layer of graphite, oxide
of iron, &c. The heat developed is always increased by the
oxidation or coating of the surface of the rods with graphite
powder. In this case the hottest extremity is always that
communicating with the positive pole ; and the most iavour-
able case for obtaining the greatest difference of temperature
between the positive and negative pole, is that in which the
surface of the negative extremity being coated with oxide or
grapiiite powder, that of the positive extremity has remained
bright. Connecting this fact with that previously mentioned
concerning the unequal heating of the two poles, it becomes
evident, that since by the transference of matter from the po-
sitive to the negative pole the surface of the two poles experi-
ences a different alteration, and that the greatest change takes
place at the negative pole, the difference of temperature must
be due, at least in part, to the difference of alteration of the
surface, which is a consequence of the fact of the transference.
I hope to have thus shown, experimentally, the connexion
which exists between the phaenomena of the voltaic arc ; and
I am led to consider them as depending on the transference
of matter from the positive to the negative pole. On the other
hand, we know from the experiments of MM. Poiret and
Becquerel, that the transfer of matter from the positive to the
negative pole is a phaenomenon independent of the develop-
ment of heat by the electric current.

XXXVIII. Notices respecting New Books.

A Treatise on Land Surveying. By John Ainslie. A new and en-
larged Edition, embracing Railway, Military, Marine and Geodetical
Surveying. By William Galbraith, M.A., F.R.A.S.

MR. AINSLIE'S book was in the main of a practical character,
but it was the work of one who knew his business well. His
directions are full and precise, and his examples numerous and in-
structive.

Mr. Galbraith, the editor of the present edition (who is well known
for his scientific acquirements and his skill in the use of instruments
of the highest class), has not only thoroughly revised Mr. Ainslie's
work, but he has added greatly to its value by the composition of an
elaborate article on Trigonometrical Surveying and Leveling, which
extends to upwards of 200 pages.

The formulee are given in the most modern form, and their use

294! Royal Astronomical Society.

exemplified in surveys of considerable extent and difficulty, in ■which
the editor has been engaged either professionally or as an amateur.

An excellent account is given of the construction and use of the
chief instruments employed in astronomy and geodetic surveying, and
a collection of valuable geodetic tables concludes the work.

We recommend this valuable work to all persons who take an in-
terest in the subject on which it treats, as the only one in our lan-
guage from which all necessary information may be obtained.

XXXIX. Proceedings of Learned Societies.

ROYAL ASTRONOMICAL SOCIETY.

[Continued from vol. xxxiv. p. 543.]

June 8, rj^HE Astronomer Royal resigned the Chair to the Rev.
1849. A. R. Sheepshanks, and then delivered to the Society
an oral statement, illustrated by models, " On Instruments adapted
to the Measure of small Meridional Zenith Distances."

The Astronomer Royal remarked that there were three distinct
ranges of observation, for which three distinct classes of instruments
had been employed. The first and most comprehensive included
the observations for zenith distances throughout the whole extent of
the meridian, from the north horizon to the south horizon ; to which
observations the mural circle and similar instruments M^ere adapted.
It was evident that constructions adapted to secure this extent of
observations in all their generality could scarcely be expected to
avail themselves of the advantages peculiar to observations confined
to one part of the heavens ; and accordingly, in nearly every in-
stance in which observations on a more limited arc of the meridian
were sufficient, instruments of the other classes had been employed.
The second class of instruments might be included under the name
of zenith sector. With this instrument, by limiting the range o
observation to six or seven degrees on each side of the zenith, a
part of the arc of meridian was embraced which sufficed for most
geodetical purposes ; that part, both from the smaller proportion of
obscuration by clouds and from the smaller uncertainty attending
the calculation of refraction, was better in an astronomical point of
view than the rest; the instrument also might, with great porta-
bility, be made of large dimensions, with long telescope and long
plumb-line, two advantages which were highly valued in the last
and in the beginning of the present centuries. Generally, its use
had been confined to geodesy ; although it must not be forgotten
that one of the most celebrated specimens of it, namely, Bradley's
zenith sector, was constructed solely for astronomical observations
at a fixed observatory ; still, however, that instrument had in prac-
tice been confined to the observation of a single star passing the
meridian within two minutes of the zenith, and it might thus be
considered as included in the third class. The third class included
those instruments specially adapted to the observation of stars pass-

Royal Astronomical Society. 295

ing within still smaller distances of the zenith. It is evident that
these, besides possessing in the highest excellence the astronomical
advantages ascribed to the second class, might be expected to enjoy
extraordinary freedom from the distortions produced by the weight
of the instrument, and might also give great facility for measures
of zenith distance by the simple use of the micrometer or the spirit-
level. This was the class of instruments which the Astronomer
Royal proposed as the subject of the present statement.

The Astronomer Royal announced that his discussion would be
confined to a critical description of three instruments : the Green-
wich 2o-feet zenith tube, now dismounted; Struve's prime vertical
instrument, now in use ; and a construction of a reflex zenith tele-
scope, proposed by himself, but not yet actually constructed. The
second of these instruments, it is true, may be used for zenith di-
stances of several degrees, but its peculiar advantages are connected
with its use for very small zenith distances. These three instruments
would be found to embody, as essential parts of their construction,
the three different methods of referring to the zenith in use in
modern times ; namely, the plumb-line, the spirit-level, and the re-
flexion from the surface of quicksilver.

I. The Greenwich zenith tube was planned and constructed by
Troughton, several years before Mr. Pond's direction of the Royal
Observatory ceased ; although, from some delays in regard to the
small but essential parts, it was not brought into use till within two
years of that time. It consisted of a telescope 25 feet long, revol-
ving in azimuth on a pin at the bottom and between guides near the
top, but absolutely confined to the vertical direction. Its range of
observation was therefore necessarily limited to that angle in which
the injurious efi^ect of obliquity of the pencil upon the image of the
star is insensible ; and practically it was confined to the single star
y Draconis, at two minutes only from the zenith. The aperture of
the object-glass was 5 inches ; the diameter of the tube at the top
6 inches, which increased at each successive step downwards (the
tube being made in five separate lengths), till it was 10 inches in
diameter at the bottom. About 6 inches below the object-glass, on
the outside of the tube, was a reel of silver wire ; the wire passed
upwards over a wheel admitting of a certain degree of end-motion,
and then passed through a hole in the side of the tube, and rested
between the threads of a screw, within the tube and 4 inches from
its top, whose axis was horizontal (a convenient arrangement for
small movements of the point of suspension), and then descended
vertically. Within the great tube was a small vertical tube, nearly
an inch in diameter ; the top of this tube was about 10 inches
below the object-glass, and here the small tube was in contact with
the side of the great tube ; the tube extended to the lower end, at
which part it was separated about 2 inches from the side of the
great tube. The plumb-line descended through this vertical tube,
and passed through a hole in the bottom plate of the telescope, and
there it carried the plumb-bob in a cup of water supported by
hooks upon the lower plate. Just above the top of the small tube.

296 Royal Astronomical Society.

or 9 inches below the top of the great tube, and consequently 5
inches below the point of free suspension of the wire, a micrometer-
microscope was fixed externally to the tube, on the same side on
which the wire tube is placed, for reading the position of the wire.
Very close to the bottom of the tube, but on the side opposite to
that on which the wire tube is placed, another micrometer-micro-
scope was placed for reading the position of the lower part of the
wire ; the wire tube here was perforated to permit vision of the
wire. This microscope was almost completely buried in the great
tube (its micrometer and eyepiece alone projecting from it) ; it was
not, however, firmly screwed down ; it was thrust in by hand into
a hole (where it was held by friction only) in a sliding-plate within
the great tube, which sliding-plate was moved by external screws.
It is evident that, if these microscopes were firm, and if the wire
retained in all positions of the instrument its peculiarities of curva-
ture, &c. in constant relation to the instrument, while its general
direction of dependence had respect to nothing but the direction of
gravity, the readings of the micrometer-microscope would give most
accurate information upon the position of the great tube with
respect to the vertical (the observation of the sides of the plumb-
wire being exceedingly delicate). Below the lower plate of the
great tube was the eyepiece of the telescope, a 4-glass diagonal eye-
piece, its eye-end projecting horizontally below the eyepiece of the
lower micrometer- microscope, and nearly to the same distance.
With this was viewed the wire (carried by a micrometer, to which
was given for distinction the name of grand micrometer), by which
the bisection of the star was effected. The lower plate of the tele-
scope was supported by four arched pieces of brass, attached to the
lower plate at its circumference, and united about 6 inches below
its centre ; and at the place of union was the pin which turned in
the foot-plate. The intervals between the brass arches left room
for the eyepiece, the micrometer, and the plumb-line cup. The
foot-plates had adjusting screws, which were, however, very rarely
used. The uj)per guides of the great tube were about 5 feet below
the top ; they were carried by an enormous iron tube, which inclosed
the great tube to within about 4 feet of the bottom, and was there
supported by large iron arches rising from four large iron pillars,
which at some distance surrounded the pier of the foot-plates, being
placed at the angles of a square, and leaving a clear space of 4^ feet
between each pillar and that opposite to it.

When the present Astronomer Royal took charge of the Royal
Observatory, he found the grand micrometer of this instrument in
the following state : — The wire-plate of the micrometer carried also
the long heavy eyepiece projecting sideways more than 6 inches ;
the long micrometer-screw extended nearly from side to side of the
lower plate of the tube, was supported at its extremities by projec-
tions from that lower plate, and was tapped through the case of the
diagonal mirror, thus acting at a distance of about 1 inch from the
wire-plate. The supports of the ends of the screw, upon whose
firmness the correctness of the action of the screw must entirely

Royal Astronomical Society. 297

depend, were thin vertical arches attached to the bottom plate only
by small thumb-screws, and these arches sustained the force of the
micrometer-screw sideways. Three arrangements more entirely
opposed to the just principles of construction of micrometers can
scarcely be conceived. The wire-plate ought not to be strained
sideways by a projecting weight, and ought not to carry any weiglit
which will increase the friction of its movement ; the action of the
screw ought to be in the plane of motion of the wire-plate ; and the
supporting point, or appui, of the screw ought to be perfectly firm.

The following changes were therefore made without delay. The
long screw was laid aside, and in its place was used a micrometer-
screw or stalk attached to the end of the wire-plate in the usual"
way ; and the micrometer was made in every respect like an ordi-
nary micrometer, the micrometer-head carrying the concave- screw
which embraces the stalk and draws it towards the micrometer-
head, the action of the screw being in the plane of the wire-plate
and directed longitudinally across the middle of the wire, and the
drawing action of the screw being resisted by springs at the oppo-
site end of the wire-plate. The motion of the micrometer was
limited in this construction to about one-tenth of the whole breadth
of the end-plate of the telescope ; but this was far more than was
required to measure the zenith distance of y Draconis ; it was,
however, made subservient to the measure of nearly the whole
breadth in the following way : — On the fixed plate of the micro-
meter ten crosses of wires were fastened, as nearly as possible at
equal distances, and on the moveable plate were fixed eleven wires
at nearly the same distances. By means of the crosses on the fixed
plate and the micrometer-movement, the interval from each wire on
the moveable plate to the next wire was ascertained, in terms of the
micrometer-screw, with great accuracy, and therefore the aggregate
or distance of extreme wires was very well known. The intervals
were also known in seconds of arc, by observations of the transits
of stars when the instrument was turned to a position distant 90°
in azimuth from its usual position. Thus the value of the screw,
and the elements for making an observation in any part of the whole
range available, were completely obtained. With this construction
of micrometer, the appui of the micrometer-head was almost close to
the bottom plate, and was perfectly firm. The eyepiece was carried
by another sliding- plate, moving in grooves unconnected with the
micrometer ; and it was moved by a separate rack and pinion. It is
presumed that in this form the grand micrometer was perfectly
trustworthy.

In the use of this instrument it is evidently necessary to observe
the same star successively in reversed positions of the instrument, the
micrometer-head being on the north side in one observation and on
the south side in the other observation ; and the values of the
grand-micrometer reading must be corrected in each observation by
quantities depending on the two micrometer-readings of the plumb-
line, in order to obtain for the two observations the angular distances
of the star from definite (though imaginary) lines in space, equally

298 Royal Astronomical Society,

inclined to the vertical, one on the north side, the other on the south
side ; and if this double operation be effected at one transit of the
star, the result for the star's zenith distance is obtained without any
computation of the star's corrections, and without any reliance on
the permanence of the state of the instrument for more than a few
minutes ; but if the observation with micrometer-head north is made
at the transit of one day, and that with micrometer-head south at
the transit of another day, it is necessary to compute the change in
the star's place (which can be done with undoubted accuracy), and
also to be assured that no change has taken place in the relative
position of the various parts of the instrument. For the details of
the calculations of every kind applicable to these cases, it is best to
refer to the introductions to the volumes of Greenwich Observations
from 1837.

For a considerable time, the instrument, not being furnished with
two wires on the micrometer-plate at a distance nearly equal to
double the star's zenith distance, could not be used for the double
observation at a single transit (as the short duration in the field of
view did not leave time enough for the numerous turns of the mi-
crometer, with change of the observer's position, &c.), and it was
therefore reversed after the completion of each day's observation.
The results of the observations were not satisfactory, and the Astro-
nomer Royal detei'mined on so fitting up the instrument that it
might be used for the double observation at a single transit.

The arrangements obviously necessary were, to fix on the micro-
meter-plate two wires at distances nearly equal to double the star's
zenith distance, and to determine their interval accuiately ; and to
provide stops for the reversion of the instrument, for the movement
of the eyepiece, and for the movement of a part of the illuminating
apparatus, which it was necessary to shift at each observation. But
another change, the necessity for which seems to have been gene-
rally overlooked, then suggested itself. It is unsafe to consider any
wire as absolutely straight : when it has once received a bend, even
no more than the bend of passing round a reel, it retains a portion
of that bend although stretched even to the breaking-point ; and
some of those curved parts of the wire may be under the micro-
scopes by which the position of the plumb-line is checked. Now
this is unimportant, provided that the bend is always turned in the
same direction relatively to the instrument ; for then its only effect
is to alter by a constant quantity the correction to the value of the
grand-micrometer reading, which constant disappears on taking the
difference of the two corrected grand-micrometer readings, upon
which, in fact, the determined zenith distance depends. But if the
position of the bend changes relatively to the instrument, the result
is affected with error. Now it is extremely probable that the posi-
tion of the bend will change ; that is, that the plumb-line will turn
relatively to the instrument at every Reversion, but more particularly
so at rapid reversion ; and some method must be adopted to prevent
this turning.

For this purpose the Astronomer Royal adopted the following

jRoyal Astronomical Society. 299

construction : — On the side opposite to the eyepiece, and attached
to the bottom plate of the telescope, a wooden box was carried out
horizontally, its bottom being nearly as low as the foot-plate, and
its top at the level of the bottom plate of the tube ; and upon the
end of this box was planted a wooden plumb-wire tube, connected
at its top with a frame attached to a higher part of the great tube
(upon which frame the wooden plumb-wire tube and the horizontal
box were, in fact, suspended). From the top of this wooden tube
was suspended (with screw-adjustment for moving it to or from the
principal plumb-line) a second plumb-line, 40 inches long, and di-
stant from the principal plumb-line about 12 inches. The two
plumb-lines supported in the horizontal box the two ends of a bar
12 inches long, and to this bar were attached one or two plumb-
bobs. A little consideration of the theory of parallel forces will
show that, if the distance between the plumb-lines at the top and
the bottom is the same (the criterion of which is, the distinctness of
the principal plumb-line in the field of view of the lower microscope,
whether the second plumb-line be used or not), the relative move-
ments of the principal plumb-line for varying inclinations of the
grand tube are the same as if the plumb-bob were immediately at-
tached to it. At the same time, the turning of the wire is effectu-
ally prevented.

The instrument was used with this construction to the spring of
1848, when it was finally dismounted. The results of observation
were more accordant than they were before introducing the last
modification, but they were not superior to those derived from the
mural circle. There can be no doubt that the remaining errors
were greater than could be attributed to mere imperfection of obser-
vation, and that they must originate in some fault of the instrument.
Generally speaking, the greatest errors coincided with the greatest
irregularities in the readings of the lower plumb-line microsco])e.
It has already been pointed out that the fixation of that microscope
was not very firm, and the irregularities may have originated in this
weakness. Or the great tube may have twisted sensibly in the
reversion. Or the plumb-line may have been bound by spider-
threads, from which it was to a certain degree set free by the move-
ment of reversion (for it was found almost impossible to keep the
wire-plate free from spider-threads, the uniform temperature and
the constantly vertical position of the telescope being probably com-
fortable to those animals). Whatever the distinct cause might be,
the Astronomer Royal considered that the instrument had failed,
and that its failure was owing to the dependence on the plumb-line ;
and he expressed his hope that he might never again be compelled
to use an instrument relying for its verification upon a plumb-line.

II. The applicability of a transit instrument in the prime vertical
to the determination of latitude of place from assumed polar distance
of the star, or vice versd (the polar distance of the star being greater
than the co-latitude of the place), has long been known ; but it seems
to have attracted more particular attention since it was used by
Struve in the determination of the diflference of latitudes at the ex-

300 Royal Astrofwmical Society.

tremities of his arc of meridian parallel to the Baltic. Whatever be
the construction of the transit instrument used, the proper method
of observation is the following : — The error of level of the axis being
ascertained, the instrument is directed to the star, while it is yet
north of the eastern prime vertical, and the transit of the star is ob-
served over each of the wires preceding the middle of the field ; the
position of the instrument being continually changed, so that the
oblique transit is observed over the centre of each wire. When the
star has passed the wire next before the middle, the instrument is
reversed ; and the passage of the star, now on the south side of the
eastern prime vertical, is observed over the same wires as before,
but in the opposite order. The error of level of the axis is then
ascertained. Then, when the star is approaching the western prime
vertical from the south, the instrument being still in its second
position, the error of level of the axis is again ascertained ; then the
transit of the star is observed again over the same wires ; before it
passes the middle of the field, the instrument is reversed to its first
position ; then the transit of the star, now on the north side of the
west prime vertical, is observed again over the same wires. Finally,
the error of level of the axis is ascertained in this position.

The reduction of the observations is made in the following form,
each wire being treated separately. The projection of each wire on
the sky is a small circle whose pole is in the north point N of the
horizon ; and if a be the angular distance of that wire from the line
of coUimation, 90° — a will be the radius of the small circle when
the star is seen on it north of the prime vertical, and 90° + a when
the star is south of the prime vertical. Form the spherical triangle
NFS ; let A be the hour-angle from the meridian, or the supplement
of the angle at P ; / the latitude of place ; ij the star's north polar
distance. Then when the star is north of the prime vertical,

cos (90° — «)= cos /.cos 5— sin /.sin 5. cos A, ;
and when the star is south of the prime vertical,

cos (90° + a)= cos /.cos 5'— sin /.sin J. cos Ao.
Adding these two equations, we obtain

cot /.cot ^= cos— lit — ?.cos — ! -.

2 2

Aj is half the interval between the first transit east and the second
transit west, and Ag is half the interval between the second transit
east and the first transit west, in both cases converted into arc.
Thus by the observations on each wire we determine with great
facility / from J, or J from /, without any knowledge of the distance
of that wire from the line of coUimation.

The mean error of level of the instrument may be applied to I
before forming the logarithm of cot / (supposing that it is the object
of the observation to determine (J). Or a correction may be applied
for it (which will be different for different stars) to the result ob-
tained with a constant value of /. The latter is the course followed
by M. Struve in reducing the observations of which I shall shortly
speak.

Royal Astronomical Society, 301

The advantages peculiar to this observation are, that it is not
affected by ordinary refraction ; and that its scale, being one of
time, is exact to a degree which is unapproachable in other ways.
Bad, indeed, must the clock be of whose rate we are not certain
within 1* per diem ; therefore the uncertainty on our time-scale
cannot practically amount to -g-o^o-Q part of the whole, and that on
the results of the observation, as depends on this cause, cannot
amount to ^ ^ ^ ^ y part of the whole. But the Astronomer Royal
stated, as the result of his own experience, that an accuracy of -^^qq
in the determination of a micrometer-scale is almost more than can
be hoped for. Other advantages which it possesses are common to
other reversible instruments. Thus if there be a constant optical
fault in the image of a star, produced by defects in the object-glass,
that fault will produce opposite effects in the first and second posi-
tions of the instrument : if the pivots be mis-shapen, as if there be a
hump upon one, yet if the form of the two Y's is similar, that hump
will take the same bearing upon the east side of one Y in one ob-
servation as upon the west side of the other Y in another observa-
tion, and its effects will be annihilated in the result : if the pivots
are unequal, the effects of the inequality are similarly annihilated.
But to secure all these advantages, the two following instrumental
points must be secured in the construction : the instrument must
admit of having the level applied to it while the telescope is in the
position of observation ; and it must admit of being reversed with
ease and rapidity. To the obtaining of these objects, the construc-
tion devised by M. Struve, and carried out by Messrs. Repsold, is
particularly well adapted. This instrument is supported upon Y's
carried by two stone pillars, about 6 feet high and 46 inches apart,
from outside to outside ; the outside face of the pillars being vertical,
and the inside faces inclined to the vertical. The axis of the instru-
ment has its bearings upon the two Y's ; but the telescope (7 feet
long) attached to this axis is on the outside of one of the pillars ; a
counterpoise at the other end of the axis being on the outside of the
other pillar. Between the two pillars is the reversing apparatus,
which also carries the ordinary counterpoises. It consists of a ver-
tical shaft, sliding through holes in cross-bars which are fixed to the
piers, and prevented by a fillet upon it from turning until it is raised
to a certain height ; this vertical shaft carries a T head about 33
inches long, at the extremities of which are the lifting-forks, and
also the fulcra of the ordinary counterpoises. 'I'he counterpoises
act by means of levers to support a bar about 41 inches long, at the
extremities of which are the friction-rollers, which at all times sup-
port the principal part of the weight of the instrument. The vertical
shaft does, therefore, at all times support the fulcra pressures of the
counterpoises ; and when the instrument is raised for reversion, by
bringing up the vertical shaft so that the lifting-forks at the ends of
the T head come in contact with the axis of the instrument, the
only additional load which is put upon the vertical shaft is that pres-
sure which was left as residual weight upon the Y's on the stone
pillars, a pressure which, in the practice of the German astronomers.

302 Royal Astronomical Society.

is very small. Two massive lever-counterpoises are therefore pro-
vided below, which act upwards under the foot of the shaft : and if
these are adjusted to support the shaft when the instrument is not
on the lifting-forks, they will also practically nearly support it when
the instrument is on the lifting-forks : so that a very trifling effort
of the hand is then necessary to raise the shaft with the instrument.
This small effort is given through a winch, acting by means of
bevel-gearing upon a large circular nut, which works on a screw-
thread cut upon the shaft, and bears vertically upon one of the cross-
bars : and thus by an exertion which appears almost fancifully small,
the instrument is raised for reversion, is turned round (the telescope
being placed horizontally), and is deposited in its new position. Of
this reversing apparatus the Astronomer Royal spoke with great
praise. Not only is the reversion effected with a rapidity and ease
scarcely to be conceived, but also the counterpoises are acting in the
same way, and the general strains upon the instrument are almost
exactly the same as when it is in ordinary use. The Astronomer
Royal has borrowed this principle (although he has applied it in a
different form), in the apparatus which he has adopted for raising
the proposed transit-circle for the Royal Observatory, in order to
give opportunity for the adjustment of its collimators.

The general form of the axis, being unencumbered by any tele-
scope crossing it, is evidently well adapted to the application of the
level at all times ; a thing which is always important, but particu-
larly necessary for the German instruments, which are frequently
counterpoised almost to the last ounce, so that there is not in them
the same security for the bearing of the pivots in their proper posi -
tion as in our instruments, in which a far greater residual weight is
left.

The instrument, therefore, and its auxiliary apparatus, are most
admirably adapted to securing the two advantages, of easy reversion
and application of the level in the position of observation, which are
so desirable for this instrument. But these advantages, in the
opinion of the Astronomer Royal, are very dearly bought by an
entire abandonment of that mechanical firmness of connexion be-
tween the telescope and the axis which is obviously necessary to
make the observations trustworthy. The kind of firmness which is
required is that which retains the telescope in a position at right
angles to its axis ; the same, in fact, as that required for a transit-
instrument. We laugh at the transit-instruments of the last cen-
tury, in which, while great pains were taken to secure length of axis
between the bearings, the central connexion was left very weak ;
and we praise the modern transit-instruments, in which the central
connexion has been made successively larger and larger, and not
least so by the German artists ; and of which a more admirable
specimen cannot be cited than the Edinburgh transit-instrument,
made by Messrs. Repsold, the constructors of Struve's prime-vertical
instrument. Yet in this prime-vertical instrument, that important
connexion is probably very far weaker than in any transit- instrument
that ever was made. The whole support of the 7 -feet telescope,

Royal Astronomical Society, 303

upon the firmness of which support the value of the observations
entirely depends, is a single perforated pivot, 4 inches in diameter,
on one side of the telescope. It is true that the telescope is sus-
tained, as regards the strain of its own weight upon the small pivot,
by an internal concealed counterpoise (for no one who has mastered
all the external counterpoises of a German instrument is therefore
to suppose that he has possessed himself of all the applications of
that principle in the interior of the instrument), whose fulcrum is in
the perforated pivot, near the telescope, and whose weight is within
the hollow case at the other end of the axis, which appears to the
eye like a large counterpoise connected with the external axis. But
this counterpoise, while it delivers the pivot from the ordinary strains
to which it would be exposed from the weight of the telescope, does
in no degree diminish the effect of what, perhaps, are really more
formidable, the accidental strains produced by pressures on the ends
of the telescope, or other accidental forces, or irregularities of forces,
not taken into account in the construction of the instrument. For
instance, if the Y's were slightly irregular, so that the principal
bearing of the pivots on the northern Y was an inch nearer to the
face of the pier than that on the southern Y (a thing which it would
be nearly impossible to discover by examination), the difference in
the bend of the axis in the two positions of the instrument would
probably be so considerable that every result would be worthless.

In the opinion of the Astronomer Royal, the asserted consistency
of results hitherto obtained with this instrument proves nothing.
Although discordance proves the existence of some fault, accordance
does not negative the existence of very great faults. The Astronomer
Royal cited the expression of Bouguer, who, after much painful ex-
perience in the construction of zenith sectors, in different forms, for
the measure of the Peruvian arc, came at last to the conclusion that
no agreement of results proved their truth, unless the logical cor-
rectness of construction of the instrument gave reason il priori for
believing that the results would be good.

One defect to which this instrument is liable was pointed out by
M. Struve himself to the Astronomer Royal. It cannot be assumed
that the temperatures of the external faces of the two piers are the
same ; and if they be not, the effects of their radiation upon the te-
lescope-tube must be different*. •

The Astronomer Royal then remarked, that though perhaps the
form of the ordinary transit-instrument would not give in their full
extent the same facilities, yet the great importance of securing the
admirable firmness and excellent connexions of the transit-instrument
made it desirable for us to attempt to unite with them, as far as
possible, the peculiar conveniences of Struve's instrument. In

* The prime vertical instrument of M. Struve, constructed by Repsohi,
is fully figured in plates 32, 33 of M. Struve's magnificent work, De-
scription de P Observatoire de Poidkova, Saint Petersbourg, 1845. Drawings
of the Greenwich zenith tube, and models of Struve's prime vertical instru-
ment and of the reflex zenith tube, may be seen at the apartments of the
Rojal Astronomical Society.

304 Royal Astronomical Society.

regard to the reversion, by a forked apparatus rising from the floor,
there is no difficulty ; the only difficulty is in the application of the
level while the instrument is in the position of observation. There
appears to be no valid reason prohibiting the use of one of the
following constructions. The level-frame might consist of two
bars extending from the pivot-forks towards the telescope, there in-
terrupted in their straight course, and united by a large oval ring,
through which the telescope could play ; each bar must then carry
a short spirit-level. Or it might consist of a parallelogrammic
frame, strengthened in the middle by a ring through which the
telescope could play, the two short sides being attached to the
pivot-forks, and the two long sides carrying two long levels. But a
different form of instrument may be suggested, allowing of the ap-
plication of the ordinary single level at all times, and apparently
embodying the conveniences of Struve's form, while it does not
abandon the strength of the usual form. The transit-instrument
may be made in the form of the letter T (the horizontal line of the
T representing the axis of rotation), the object-glass of the tele-
scope scarcely rising above the thick part of the axis. As the weight
of the telescope is entirely on one side of the axis, it must be ba-
lanced by counterpoises carried by a very large fork ; the stalk of
the fork being within the telescope-tube, the two arms of the fork
being in the axis of the transit, and resting within the pivots for a
fulcrum, but projecting out beyond the pivots ; and the two prongs
of the fork projecting towards the object viewed by the telescope,
and being loaded with the counterpoises at their ends.

If, however, we rely upon our transit taking the same bearing in
the Y's after reversion, a very much simpler principle may be used,
dispensing entirely with the level. It is only necessary, after having
miade the observations on the north side of the east prime vertical
(as already described), to reverse the instrument and to observe on
the south side of the east prime vertical by reflexion in a trough of
quicksilver ; then to reverse and observe on the south side of the
west prime vertical by reflexion ; then to reverse again, and to
observe, by direct vision, on the north side of the west prime vertical.

The Astronomer Royal expressed himself confident that in some
of these ways the advantages of Struve's construction might be
secured, with the additional guarantee for the goodness of the results,
that they are obtained with an instrument of firm mechanical con-
struction.

The Astronomer Royal then explained that his attention had been
directed to these constructions by the necessity created by the pre-
sent condition of astronomy for a few accurate observations, at what-
ever trouble obtained, of stars near the zenith. Struve's instrument
is now employed on three stars only, and M. Struve is satisfied if
of each of these stars he can obtain eight observations in a year. At
Greenwich there is special need of observations of one star, namely
y Draconis, a star that may with propriety be considered as the
birth-star of English Astronomy. Unfortunately no instrument on
the prime vertical principle is applicable to this star, because it passes

Royal Astronomical Society. 305

north of the zenith of Greenwich. The Astronomer Royal therefore
has been compelled to endeavour to devise an instrument which shall
be firm in its connexions, and shall also be api^licable to the obser-
vations of stars on both sides of the zenith. The following is the
construction which he proposes for this purpose.

III. The proposed reflex zenith telescope is founded upon these
considerations. If an object-glass be placed with its axis vertical ;
and if a pencil of light fall on it from a star near the zenith, and
pass from the object-glass with its axis still inclined to the vertical,
but with the rays of the pencil in a state of convergence ; and if a
trough of quicksilver be placed below it at a distance somewhat less
than half the focal length of the object-glass ; the pencil of light
will then be reflected from the quicksilver with its axis still inclined
in the same degree to the vertical, and with the rays still in the same
state of convergence, and will again pass through the object-glass,
and will form an image of the star at a very short distance above the
object-glass, and at a distance from the axis of the object-glass de-
pending on nothing but the star's zenith distance and the focal
length of the object-glass. Although we cannot fix on the axis of
the object-glass, yet we know that if the object-glass is turned
through 180°, the image will now be formed at an equal distance
from the axis of the object-glass, but in an opposite direction rela-
tively to the frame of the object-glass ; and therefore the distance
between the two positions of the image, as measured by a micrometer
attached to the frame of the object-glass, will be double the distance
of either image from the axis of the object-glass, and will therefore
be a measure of the star's zenith distance. The peculiar advantage
of this construction is, that it requires no firmness of connexion ex-
cept that of the micrometer with the frame of the object-glass. The
mercury-trough may be totally unconnected with the rest of the
instrument. The firmness of support of the object-glass is unim-
portant ; for, however much the object-glass is pushed sideways
(giving the same movement to the image of the star), the micrometer
is equally pushed sideways, and the measure of the image is not
disturbed. 'J'he peculiar disadvantage is, that the light must be
reflected from quicksilver, and must pass again through the object-
glass, and must be transmitted through a four-glass eyepiece with
a diagonal reflector, so that the whole loss of light will be consider-
able. But this disadvantage appears insignificant in comparison
with the advantage.

Theoretically, the place of the image will be aff^ected bj'^ a local
fault in that part of the object-glass through which the rays pass the
second time. But, practically, the existence of such a fault is un-
likely ; and its effect, if any existed, would be proportional to the
distance of the image from the object-glass, and therefore small : and
moreover it could be ascertained and measured by previous experi-
ment on the object-glass. No injury, therefore, to the results, and
no real inconvenience to the observations, would arise from such a
fault.

The only risk to which this construction appears to be exposed is
Phil. Mag. S. 3, Vol. 35. No. 236. Oct. 1849. X

306 JRoyal Astronomical Societj/.

the following. If the object-glass with the micrometer attached be
tilted, the place of the image of the star upon the micrometer will
be disturbed by a small quantity, unless the plane of the micrometer
be at one certain distance from the object-glass. It is therefore an
important matter to determine what that certain distance will be.
It is easily seen that if the plane of the micrometer pass through one
of the points called focal centres, this condition is satisfied. For a
ray from a vertical star passing through the focal centre (the object-
glass being inclined), will be refracted in a parallel vertical direction
to the quicksilver, and will then be reflected back from the quick-
silver in the same line, and will by refraction be made to pass again
through the same focal centre ; and, supposing the distance of the
quicksilver to be properly adjusted, so that the image of the star is
formed on the micrometer, that image will be at the focal centre
whatever be the inclination of the object-glass. The place of the
focal centre may be determined by an apparatus, in which the object-
glass is planted in a frame that admits of being slid in a direction
perpendicular to its plane, the sliding- cell being upon aboard which
turns in its own plane on a pin ; a beam of light is directed upon
the lens through two narrow slits ; and a telescope is placed on the
opposite side of the object-glass to receive the light ; when, by trial
of sliding the frame, a position is so determined that, upon rotating
the turning-board, through a large angle, the position of the beam
of light as seen in the telescope does not change, it is then certain
that the focal centre is in the axis of rotation. If the micrometer
can be conveniently fixed at this distance from the object-glass, the
accidental inclination of the object-glass will be unimportant ; if the
micrometer is at any other distance, there will be a very small cor-
rection to the measures, depending on the inclination of the object-
glass ; and it will be proper that a small spirit-level be attached to
the object-glass frame for the measure of the inclination. Perhaps
in any case this addition will be prudent.

The adjustment to focal length will depend upon nothing but the
distance between the object-glass and the quicksilver ; and a power
of altering this distance must be retained. It is proposed to do this
by moving the tube, in which the object-glass turns, up or down
by a rack-and-pinion motion, the tube and its load being as nearly
as possible balanced by a lever-counterpoise. It is also proposed
that a smaller quicksilver-trough, communicating with the larger,
should carry a float, from which a light stalk should rise by the side
of the object-glass frame ; if this stalk be made of the same material
as the micrometer, a scale upon the stalk will indicate the value of
the micrometer-scale as corrected for thermal expansion, and as
affected by any change of focal length.

Although such an instrument may be adapted to the observation
of any stars which pass within a field of view expressed by the
breadth of the object-glass, yet some conveniences of fixation are
gained by limiting it to the one star y Draconis. The following are
the details of mounting proposed by the Astronomer Royal. The
micrometer necessarily requires two metallic bars crossing the object-

Royal Astronomical Society. 807

glass ; and upon reversing the object-glass, with micrometer attached,
the two bars will again occupy the same position in space. Conse-
quently there will be no additional interruption oflight if the support
of the prism-reflector of the eyepiece be two bars in the vertical
planes which pass through the micrometer- bars, carried by crooked
projections from the tube in which the object-glass turns (and there-
fore not reversed with the object-glass). And as the prism-reflector
intercepts a small portion of the object-glass excentrically, a corre-
sponding portion equally excentric on the opposite side must be in-
tercepted by a small plate carried by the two bars, in order that the
difi^raction-disturbance of the star's image may be symmetrical. One
lens of the eyepiece will be below the prism-reflector, and one close
to its vertical, or nearly vertical, face (unless it be thought preferable
to produce the effect of lenses, by grinding the faces of the prism-
reflector to spherical forms) : the remaining lenses of the ej'^epiece
(namely, the field-glass and the eye-glass) will be fixed in a tube,
entirely exterior to the object-glass and therefore causing no addi-
tional loss of light, carried by a crooked projection from the tube in
which the object-glass turns. These crooked projections permit the
micrometer-heads and reversing-handle, &c. to pass, in the reversion
of the object-glass.

Notwithstanding the great simplicity and compactness of the
essential parts of this instrument, the Astronomer Royal thinks it
desirable that it be so arranged that a double observation can be
made at each transit of the star. It is necessary for this purpose
that two wires be fixed in the micrometer plate, at an interval cor-
responding nearly to the double zenith distance of the star. By
fixing temporarily in the immediate field of view of the eyepiece a
cross of wires, or by planting a microscope for the opcasion above
the micrometer frame, the interval between these two wires may be
found very accurately in terms of the revolutions of the micrometer ;
and by fixing other wires on the micrometer plate at intervals as
nearly as possible equal to that interval, and by using a series of
microscopes fixed for the occasion, the micrometer-scale intervals
between all these wires may be very accurately found. And by
turning the object-glass and attached micrometer to a position 90°
distant from either of the positions of observation, and observing the
transits of zenithal stars over all the wires, the intervals in arc may
be found. The combination of these will give the best possible in-
formation on the value of the micrometer- scale, and on the intervals
of the wires.

A simple micrometer might be used for the observation ; it would,
however,have these disadvantages; that the micrometer must be read
between the two observations, and that the observer could not use
the same hand in the two actions upon the micrometer head. The
Astronomer Royal proposes a more complex micrometer, in which
the micrometer B, to which the bisection- wires are attached, is car-
ried by and has its screvf-appui in a micrometer A ; and the micro-
meter A has its screw-appvi in the cell of the object-glass. There
is no difficulty in so arranging this that the movement of micrometer

X2

308 Intelligence and Miscellaneous Articles,

A shall not tend to disturb the relative place of micrometer B, and
that the movement of micrometer B shall not tend to disturb the
absolute place of micrometer A (A and B standing in exactly the
same relation as the tangent- screw of a mural circle, and the micro-
meter in its telescope) : and then the observation may be conducted
in this manner. One wire being very nearly in the position for bi-
secting the star, A will be read, and the bisection will be completed
by B. Without waiting to read the micrometer head, the object-
glass, &c. will be reversed, and the second bisection will be com-
pleted by A. Then A and B will be read. It will be proper some-
times to effect the reversion in the opposite order : and for this
purpose, using the same hand on the micrometer, B must be read
before beginning, and the first bisection must be completed by A,
and after reversion the second bisection must be completed by B.
In either case the complete double observation may be obtained
with great rapidity, but without the smallest hurry.

The Astronomer Royal expressed his belief that an instrument
thus constructed might be expected usually to give results accurate
to one-tenth of a second of arc.

The Astronomer Royal then stated that, before attaching any
name to this construction, he had requested the assistance of the
Master of Trinity College, Cambridge, whose authority in a philo-
logical question of this kind is undisputed. Doctor Whewell has
fixed on the name " The Reflex Zenith Telescope ; " a name which
appears to express with singular accuracy the peculiarities of its
construction, and which the Astronomer Royal hoped would be
universally adopted.

XL. Intelligence and Miscellaneous Articles.

ON CARBONATE OF LIME AS AN INGREDIENT OF SEA-WATER.

To the Editors of the Philosophical Magazine and Journal.
Gentlemen, September 6, 1849.

1 N the current Number of the Philosophical Magazine appears an
*- abstract of a paper by Dr. Davy On Carbonate of Lime as an
Ingredient of Sea-water, from which, according to the author's in-
ferences, it appears that "carbonate of lime, except in very minute
proportion, does not belong to water of the ocean at any great di-
stance from land." But with all deference I would submit that this
may be true as regards the surface only ; and that the bottom of the
sea, even at its greatest distance from land, may be equivalent to
" proximity to coasts," the point urged by Dr. Davy.

That there are grounds for such a supposition, and for believing
that no inconsiderable quantity of carbonate of lime does exist at the
bottom of the ocean far from land, is apparent in Darwin On Coral
Reefs, where instances are given of living corals and corallines being
taken up from great depths ; and taking the presumption that the
base of some of the remote coral islets of the Pacific, whose perpen.

Intelligence and Miscellaneous Articles. S09

dicular wall descends to immense depths, is the same as the summit,
we have further evidence that carbonate of lime does exist, or has
existed, in such situations — far from coasts.

Again, Sir James C. Ross, in his Voyage to the Southern Seas
(vol. i, pp. 202, 203, 207, 208), relates that on one occasion the
dredge was put over in 270 fathoms and brought up living coral ; a
day or two afterwards corallines were obtained in 300 fathoms ; and
speaking of the maintenance of organic life under pressure, he ob-
serves, " hitherto we have not been able to determine this point
beyond a thousand fathoms, but from that depth several shell-fish
have been brought up with the mud." Sir James appears to believe
that their existence at greater depths is not impossible ; for he pur-
sues, "as we know they can bear the pressure of one thousand
fathoms, why may they not of two ? "

I leave it to your judgement whether the foregoing remarks are
worthy of publication, and remain.

Your obedient Servant,

Walter White.

GOLD IN CERTAIN MINES OF THE DEPARTMENT OF THE RHONE.

MM. AUain and Bartenbach state that the coppermines of Chessy
and of Saint Bel (Rhone) have been the objects of interesting ex-
periments; the result of which is, not only that the copper and zinc
which the pyrites contains may be easily extracted, but that it con-
tains also at least 1-10,000 of gold. According to analyses, the
numerical results of which are not stated by the authors, the pyrites
contains sulphur, iron, zinc (about 8 per cent.), copper (about 5 per
cent.), silica, arsenic, and gold, 1-10,000 at least. This discovery
of gold has naturally led to the performance of a series of opera-
tions, in order to find an oeconomical method of extracting this metal.
Although the experiments are not entirely finished, the authors
consider that the separation of this small quantity of gold is easy
and oeconomical, and that the copper, zinc, and sulphuric acid ob-
tained, will partly cover the expenses of extraction ; the method is
briefly as follows : — The sulphur and arsenic being expelled by roast-
ing, and the oxides of zinc and copper formed dissolved by sulphuric
acid, the residue, which is composed of silica, sesquioxide of iron
and gold, is to be washed, and then treated with a cold aqueous
solution of chlorine ; after some hours' action a solution of chloride
of gold is obtained, from which the metal is reduced by the usual
processes ; the chlorine in this case does not act upon the sesqui-
oxide of iron Llnstiiut, Aout 8, 1849.

ON THE ANALYSIS OF PLANTS BY INCINERATION.
BY M. CAILLAT.

The author, who is professor at the Agricultural Institute of
Grignou, is of opinion that incineration, generally hitherto employed

310 Intelligence and Miscellaneous Articles.

for obtaining the inorganic matters of plants, yields incorrect results;
that the sulphates contained in the plant so treated are in great mea-
sure decomposed, and that the sulphuric acid or sulphur escapes in
large proportion among the gaseous products of combustion.

It occurred to M. Caillat to treat the residues of plants, such as
lucern, trefoil and sainfoin, with dilute nitric acid, and he succeeded
in separating almost the whole of the mineral substances which they
contained ; so that the pulpy residue of 10 grammes of the substance
employed, after washing and drying, burnt readily, leaving only 18,
20, or 22 milligrammes of ashes. This small residue consisted of
silica and a little peroxide of iron, substances both insoluble in the
acid employed. This method of treating plants always yielded the
author a larger proportion of mineral substances than he obtained
from the same quantity of the same plants by incineration ; and in
certain vegetables he found a much greater quantity of sulphuric
acid than has hitherto been stated.

M. Caillat states, that he found by experiment that the loss of
sulphuric acid occasioned by incineration is derived from the decom-
position of a part of the sulphate of lime. Thus on intimately mixing
with starch and water a known quantity of pure and calcined sul-
phate of lime, and incinerating the mass, the collected ashes did not
contain as much sulphuric acid as the sulphate of lime employed.

The author has also stated another direct experiment, which shows
that the sulphate of lime converted into sulphuret of calcium by the
influence of the organic matter, at a high temperature, is partly con-
verted into carbonate of lime by the action of the oxygen of the air.
The oxygen gas, burning at once the sulphur of the sulphuret and
a portion of carbon interposed, forms sulphurous acid, which is
evolved, carbonic acid, part of which remains combined with the
lime, facilitating thereby the displacement of the sulphur. — L'ln-
stitut, A out 8, 1849.

BLUE ARSENIATE OF COPPER. BY M. REBOULLEAU.

The author had proposed to employ the above-named compound
both as an oil and as a water colour ; but he has since found that,
owing to the action of the oil on the oxide of copper, the colour
becomes bluish-green ; in fact, that the arseniate acts with oil like
verditer and other blue preparations of copper.

If equal parts of common arseniate of copper and neutral arseniate
of potash be mixed and heated, the compound melts, and yields on
cooling a fused, perfectly transparent mass of a bluish-green colour,
a vitreous fracture and very fusible. The resulting compound is a
double arseniate of potash and copper obtained in the dry way by
M. Berthier's process. Whilst the double arseniate is in perfect
fusion, if one-fifth of its quantity of powdered nitrate of potash be
projected into it, brisk effervescence ensues, and a large quantity of
nitric oxide is disengaged. The crucible then removed from the
fire contains a magnificent blue substance, formed of sub-arseniate

Intelligence and Miscellaneous Articles, 3 1 1

of potash and arseniate of copper, in the state of a double salt.
When this compound reduced to powder is treated with water, the
double salt is decomposed ; the water carries off the arseniate and
nitrate of potash, and leaves a precipitate of arseniate of copper of
an admirable blue colour.— Z7«5ft<Mf, Aout 1, 1849.

ON METHYLAMINE AND ETHYLAMINE.

M. Adolphe Wurtz has described the preparation and properties
of the above compounds, belonging to a class of substances to which
he has given the name of compound ammonias (ammoniaques com-
posees).

Methylamine. — The process by which this base was obtained
does not differ from that employed by chemists in preparing am-
monia. Perfectly dry hydrochlorate of methylamine is mixed with
twice its weight of quicklime, and the mixture is^ introduced into a
long tube closed at one end, so as to occupy half of it. The other half
is filled with fragments of potash, to which a tube is adapted for
conveying the gas to an air-jar filled with mercury. The tube is to
be slightly heated, beginning at the closed end ; methylammoniacal
gas, displaced by the lime, is abundantly liberated, and received in
the air-jar filled M'ith mercury.

Methylamine thus prepared is a non-permanent gas. At about
S2° F. it condenses into a very moveable liquid. Its odour is strongly
ammoniacal. Its density was found to be 1*13 ; it is therefore rather
more dense than atmospheric air. The experimental result is rather
higher than the theoretical, which is r075. This is undoubtedly
owing to the temperature at which the experiment was made, the
gas being too near its point of liquefaction.

Methylammonla gas is the most soluble of all gases hitherto
known. At the temperature of about 53° F. one volume of water
dissolves 1040 volumes; a higher temperature diminishes this solu-
bility, as might be expected. At 77° F. water dissolves only 959
times its volume.

Like ammonia, it is instantaneously absorbed by charcoal, and also
resembles it in immediately rendering reddened litmus paper blue ;
when exposed to the vapour of hydrochloric acid, it forms a very
thick white smoke. Like ammonia, it absorbs an equal vglume of
hydrochloric acid gas, and half its volume of carbonic acid gas. It
is distinguished from ammoniacal gas by the circumstance that, when
exposed to flame, it takes fire and burns with a yellowish flame.

The composition of methylammonla gas is represented by C^H* N
= 4 vols.

An elegant and rapid analysis of this gas is effected by heating it
with potassium in a bent tube : cyanide of potassium is formed and
hydrogen is evolved, C'^ H^ N + K=C2NK + H5.

The solution of meth}lamine has the strong odour of the gas itself.
Its taste is caustic and burning. Iodine reacts upon the solution of
methylamine, and is converted into a powder of a garnet- red colour ;

312 hitelligence and Miscellaneous Articles.

and the liquor, which hardly becomes coloured, contains hydriodate
of raethylamine IH, C^ H* N. The red insoluble compound formed
as described is analogous to iodide of nitrogen.

The salts of magnesia, alumina, manganese, iron, bismuth, chro-
mium, uranium, tin, lead and mercury, are precipitated by methyla-
mine as they are by ammonia.

The salts of zinc are at first precipitated, and of a M'hite colour;
but the precipitate redissolves in a large excess of the reagent ; the
salts of copper are precipitated of a bluish-white colour; excess re-
dissolves the precipitate, forming a solution of a deep blue colour;
the salts of cadmium, nickel and cobalt, are precipitated by the so-
lution of methylamine, but excess does not redissolve the precipitates.

Nitrate of silver is completely precipitated by methylamine ; the
oxide of silver dissolves readily in an excess of the reagent. When
this solution is suffered to evaporate spontaneously, a black substance
is precipitated which is analogous to fulminating silver. This sub-
stance does not explode either by a blow, or by the action of heat ;
chloride of silver itself dissolves in solution of methylamine.

Chloride of gold is precipitated of a brownish-yellow ; an excess
readily dissolves the precipitate, forming an orange-coloured solu-
tion. A concentrated solution of chloride of platina gives with me-
thylamine a crystalline deposit in orange-coloured scales, consisting
of a double hydrochlorate of methylamine and platina.

Ethylamine. — This base was obtained by decomposing hydro-
chlorate of ethylamine by lime, in the same manner as methylamine.
Excepting that as ethylamine condenses readily, and is liquid at
common temperatures, the delivery-tube is surrounded with ice, or
still better by a freezing mixture ; the ethylamine distilled at a mo-
derate heat condenses in the receiver.

In a pure state, it is a light, very moveable, and perfectly limpid
liquid. It boils at about 64° F. When poured on the hand it vo-
latilizes, instantly producing very considerable cold. It gives out
an extremely penetrating ammoniacal odour ; its causticity may be
compared to that of potash. Ethylamine renders litmus paper which
has been reddened strongly blue; when exposed to hydrochloric
acid it yields dense white vapours. Every drop of acid added to it
produces a whistling at the moment of its mixing with the base.
Barytes and potash remain in contact with it at common temperatures
without alteration. When exposed to flame, ethylamine takes fire
and burns with a bluish flame. It mixes with water in all propor-
tions, giving out much heat, and yielding a solution the basic pro-
perties of which are exactly similar to those of methylamine ; hydrate
of copper is, however, most readily soluble in ethylamine.

Chloride of platina is not precipitated by ethylamine. When a
solution of ethylamine is mixed with oxalic aether, the mixture soon
becomes turbid ; alcohol is formed ; very slender crystals separate
of a compound which is to oxamide what ethylamine is to ammonia ;
it is ethyloxamide, the composition of which is represented by
Q6 116 ]^2 o^^. The composition of anhydrous ethylamine is repre-
sented by the formula C* H^ N.

Intelligence and Miscellajieous Articles, 313

One hundred parts give —

Experiment. Theory.

Carbon 54*4; . . 54*3

Hydrogen 15*9 . . 15*5

Nitrogen 30-9 31-3 31-2

Comptes Rendus, Aout 13, 1849.

ON VALERAMINE OR VALERIC AMMONIA.

M. A. Wurtz states that cyanate of amylene, which he obtained by
distilling sulphaniylate of potash with cyanate of potash, is easily
decomposed by solution of potash. The reaction, favoured by the
action of heat, gives rise to carbonate of potash and a volatile base,
valeramine, which distils when the solution of potash is boiled. It
is found in the receiver in solution in water which is volatilized and
condensed with it.

On saturating this solution of valeramine with hydrochloric acid, a
perfectly neutral hydrochlorate is obtained, which by evaporation is
obtained in the form of white scales, greasy to the touch, very so-
luble in water and soluble in alcohol ; it does not deliquesce in the
air. By analysis it yielded —

Experiment. Calculation.

Carbon 48'2 48-5

Hydrogen 11-4 11*3

Chlorine 28-3 28-7

Nitrogen 11'5

This analysis agrees perfectly with the formula HCl, C'^' H'^ N.

The accuracy of this formula was verified by analysing the double
salt M'hich is precipitated when concentrated solutions of chloride
of platina and hydrochlorate of valeramine are mixed. As it is con-
siderably soluble in water, it is advantageous to add a little alcohol
to the mixture. After having collected and pressed the precipitate,
it is to be redissolved in boiling water ; on cooling, it precipitates
in fine scales of a golden-yellow colour, the composition of which is
represented by the formula HCl, 0'° H'3 N, PtClS as deduced from
the following results of the analyses: —

Experiment. Calculation.

Platina 32-6 32-9

Chlorine 36-0 36-5

Carbon 20-4 20-5

Hydrogen

Nitrogen 4'8 4*8

When hydrochlorate of valeramine is distilled with lime, the vola-
tile valeramine passes over into the receiver. When pure, this base
is liquid ; its taste is both burning and bitter, and its odour strongly
ammoniacal. It is soluble in water, and the solution precipitates the

314' Intelligence and Miscellaneous Articles,

salts of copper, an excess redissolving the precipitate, yielding an
azure blue solution ; this effect is, however, produced with greater
difficulty than with ethylamine, methylamine or ammonia. Valera-
raine also precipitates nitrate of silver ; the precipitate is of a fawn-
colour, and adheres like a resinous mass to the bottom of the vessel.
An excess of the reagent whitens and completely dissolves it. Chlo-
ride of silver is dissolved by valeraraine, but with more difficulty
than by ammonia. — Comptes Rendus, Aout 13, 1849.

ON CHLOROFORM. BY MM. SOUBEIRAN AND MIALHE.

Two liquids are sold in commerce under the name of chloroform ;
and though of very different origin, they are considered as identical,
and are accordingly substituted for each other. Nevertheless there
are notable differences in their properties : one, derived from the
reaction of hypochlorite of lime upon alcohol, possesses all the pro-
perties which one of the authors of this memoir has assigned to
chloroform ; it is that which may be called normal chloroform ; the
other, obtained by the action of hypochlorite of lime on pyroxylic
spirit, is so different from the first, that the authors have submitted
them to a minute examination in order to discover the cause of the
difference.

The chloroform from pyroxylic spirit, which the authors provi-
sionally call methylic chloroform, although possessing the same phy-
sical appearances as normal chloroform, has quite a different odour :
this odour is not sweet and agreeable, but empyreumatic and nau-
seous. Its density is less than that of common chloroform ; the
latter being 1-496, the former 1-413*. Its boiling-point appears also
to be not so high ; lastly, the inhaling of methylic chloroform is
so far from being easy and agreeable, that it occasions general un-
easiness, followed by heaviness of the head, continued nausea, and
sometimes vomiting.

Such differences in the properties of these two liquids induced the
authors to think that they did not possess the same composition, or
that the properties of one of them was masked by some foreign
substance.

On the first hypothesis, it might be thought that chloroform,
which does not belong to the same chemical type as alcohol, and
which is formed by the powerful reaction of chloride of lime, may
be a different body according as it is formed from alcohol, which
belongs to the ethyle series, or from pyroxylic spirit, which belongs
to that of methyle. It may happen, also, that the difference de-

* The authors remark in passing, that the density of chloroform, stated
by M. Liebig to be 1-480, is too light; they constantly obtained it of 1*496
at 54° F. The difference is unquestionably derived from the presence of
some foreign body, which it was not known how to separate from the chlo-
roform, as the authors will presently show.

Intelligence and Miscellaneous Articles. SIS

pends on the greater or less condensation of the methyle, which may
be supposed to exist in both chloroforms.

In this uncertainty the authors undertook analyses, the results of
which will be hereafter stated. The second hypothesis supposes the
identity of the chloroforms formed from alcohol or from jjyroxylic
spirit. The difference in this case would be derived from the pre-
sence of a foreign body. This opinion is the best founded. In fact,
the authors found, by endeavouring more perfectly to rectify methylic
chloroform on chloride of calcium, that the salt which remained in
the retort contained a quantity of a peculiar oil, easily separable by
washing with water : by repeated rectifications, 30 grammes of this
oil were obtained from 500 grammes of some commercial chloroforms.

This new substance was liquid, and of an oily consistence. At
first yellowish, it became colourless by simple rectification. It had
a very peculiar and strong empyreumatic odour, which was recognized
as the cause of the peculiar odour of methylic chloroform ; it was
lighter than water ; submitted to distillation in a retort containing
a thermometer, it began to distil at 1 85° F. ; but this temperature
was so far from remaining fixed, that it rose to 244° F. At this
moment the operation was interrupted, because the thermometer, on
account of the small quantity of the remaining oil, did not dip into it.

This increase of temperature during the distillation evidently de-
notes a mixture of various compounds. This heterogeneous oil
burnt readily with an intense sooty flame. The presence of chlorine
among the products of combustion showed that this body was a
constituent part of its elements.

The chloroform, several times rectified for the production of this
oil, did not retain the slightest pyrogenous odour which characterizes
it. Some chemical reaction was then searched for, which, while it
would not react upon the chloroform, was capable of separating or
destroying the oil that it contains. After some trials, concentrated
sulphuric acid appeared to answer the purpose : it occasioned the
impure chloroform to assume a brownish-red colour, the intensity of
which was greater in proportion to the quantity of oil in the mix-
ture. When colour ceased to be produced in the chloroform, it no
longer retained the empyreumatic odour.

The authors state that, without the fear of incurring any sensible
error, they were able to analyse the chloroform thus purified, and to
examine and compare its properties with those of normal chloroform.
The analyses, densities, in the liquid state and that of vapour, were
all found to be similar ; and satisfactory proof was obtained that
only one chloroform exists ; and that which is prepared from py-
roxylic spirit does not differ from that obtained from alcohol, when
all the oil above described has been separated. It must, however,
be admitted, that the complete separation of this oil was not effected ;
there still remained a very minute portion of it, so small as not to
affect the density or the results of analyses ; but it was distinguish-
able by its odour, which remained after the evaporation of a consi-
derable quantity of chloroform. It was peculiarly sensible in the

316 Intelligence and Miscellaneous Articles.

operation of determining the density of its vapour ; the matras after
the operation retained the peculiar odour of this chlorinated methylic
oil. It is almost impossible to get rid of the last traces of it : it
resists the action of concentrated sulphuric acid, even when the
chloroform is long exposed to it.

There do not, then, exist two chloroforms ; the cause of the ap-
parent difference is the presence of the peculiar oil produced by the
reaction of chloride of lime on pyroxylic spirit.

This fact being established, search was instituted to determine
whether, during the preparation of chloroform from alcohol, an
analogous substance was formed. Experiment confirmed suspicion ;
the rough chloroform was washed first with water and afterwards
with carbonate of soda ; it was long kept in contact with chloride
of calcium to combine with the water ; lastly, it was filtered and
distilled in a water-bath from a glass retort. There remained in the
retort a liquid aromatic substance, but of an odour very different
from that of chloroform ; the proportion was very small, for not
more than 40 grammes were obtained from 20 kilogrammes of chlo-
roform.

This oil differs essentially from that obtained from chloroform
prepared from pyroxylic spirit. It is more dense than water, has a
peculiar acrid and penetrating odour, not at all resembling that of
the other oil ; but like it, it was found to be a mixture of different
compounds; for the thermometer, which on heating was 134° F.
at the commencement of ebullition, became as high as 242° F. ; and
the temperature would undoubtedly have been increased if the ex-
periment could have been tried with a larger quantity. All these
compounds are chlorinated, as proved by examining the results of
their combustion.

It results from the preceding statements, that as chloroform ob-
tained from pyroxylic spirit cannot be entirely deprived of its pyro-
genous odour, it ought not to be employed for inhaling. The pre-
sence of chlorinated oil, in the small quantity even in which it exists
in chloroform obtained with alcohol, has a strongly-marked influence
in its employment : it is to it that must be attributed the uneasiness,
nausea and vomiting, occasioned by inhaling chloroform.

It follows that it is absolutely necessary to rectify chloroform by
distillation in order to separate the foreign body which it contains,
and moreover the distillation should be stopped sufficiently soon.

In concluding, the authors remark that chloroform, like hydro-
cyanic acid, when poured on filtering paper, partly evaporates so
rapidly as to occasion sufficient cold to solidify the remainder in
white silky tufts, which remain for a few seconds.

The authors conclude from the facts above stated, that —

1st. Chloroform prepared from pyroxylic spirit is identical with
chloroform properly so called.

2nd. The purification of methylic chloroform is too difficult to
admit of its advantageous substitution for normal chloroform.

3rd. During the preparation of chloroform there is always pro-

Intelligence and Miscellanemis Articles. S17-

duced a certain quantity of pyrogenous, essential chlorinated oil,
the action of which on the animal oeconomy is extremely hurtful.

4th, It is indispensable to free chloroform from this chlorinated
essential oil, by not continuing the rectification too long. — Journ.
de Pharm. et de Ch.. Juillet 1849.

ON THE PREPARATION OF NITROGEN GAS.
BY M. B. CORENWINDER.

The preparation of nitrogen is attended with several inconveni-.
ences : there is no one of all the processes employed by which it can
be obtained rapidly and pure, without much precaution and the use
of complicated apparatus. This circumstance induced the author to
publish the method by which he obtains in a few minutes a large
quantity of this gas, and in a state of absolute purity, as shown by
experiments related below.

This process is derived from the decomposition of nitrite of am-
monia, which, as is well known, is resolved by heat into nitrogen
and water ; but as this salt is difficult to prepare, it is replaced by a
mixture of alkaline nitrite of potash and hydrochiorate of ammonia,
a mixture which contains the elements of nitrite of ammonia and
chloride of potassium.

In order to obtain the nitrite of potash in a proper state, it is
requisite to employ a solution of caustic potash, of density 1*38, and
to pass into it nitric oxide obtained from the decomposition of one
part of starch by ten parts of nitric acid, until a distinctly acid pro-
duct is obtained, and afterwards to add to it caustic potash, so as
to render it decidedly alkaline.

The nitrite thus prepared may be kept without undergoing alte-
ration, so that a quantity of it may be prepared ; and when nitrogen
is required, it is sufficient to mix concentrated solutions of one vo-
lume with three volumes of hydrochiorate of ammonia, and to heat
the mixture in a retort by a charcoal fire ; the disengagement soon
commences, and continues with perfect regularity.

As it is necessary, in order to have the gas pure, that the nitrite
should be alkaline, it will be expected that a small quantity of am-
monia will be evolved ; but this disengagement is unattended with
any inconvenience ; if the nitrogen gas be required completely de-
prived of this alkali, it is sufficient to pass it through water acidu-
lated with sulphuric acid contained in a bottle.

The following experiments left no doubt as to the purity of the
nitrogen gas thus obtained : —

1st. After having deprived it of ammonia in the manner above
stated, it was passed into a bottle containing a mixture of zinc,
sulphuric acid and water, and consequently in the presence of nas-
cent hydrogen.

The experiment was continued for a considerable time ; and when

3 18 Intelligence and Miscellaneous Articles,

it was terminated, there was not the slightest indication of the pre-
sence of ammonia in the solution. The result was equally negative
with sulphuret of iron and dilute sulphuric acid.

2nd. A certain weight of copper recently reduced by hydrogen
was placed in an organic analysis glass tube, and subjected for about
half an hour to the action of a red heat and a current of washed
nitrogen, which had been afterwards dried by pumice-stone and
sulphuric acid, taking the precaution of not heating the tube till
after all the atmospheric air had been driven out by the disengage-
ment of the gas. The experiment was repeated several times, and
no alteration was observable in the exterior appearance of the copper,
nor had it increased in weight. — Ann. de Ch. et dePh., Juillet 1849.

ON THE QUANTITY OF AMMONIA CONTAINED IN ATMOSPHERIC
AIR. BY M. R. FRESENIUS.

In the following table the author has arranged the results of his

own experiments and those of MM. Grager and Kemp ; 1,000,000

parts of air contain —

Oxide of Carbonate of

Ammonia. ammonium, ammonia.

Grager 0-333 0'508 0-938

Kemp 3-880 5-610 10-370

^ . /day 0-098 0-153 0-283

rresenms ^^jgj^j. ^.^g^ q.^^^ ^.^^^

Fresenius' mean 0133 0205 0-379

The proportional quantities of ammonia found by these chemists
are —

Fresenius 1 day

Fresenius 1*7 night

Grager , 3-4

Kemp 37-5

M. Fresenius observes that he is far from setting a high value
upon his experiments, though he took great care in all his operations ;
he is, however, of opinion that he may draw the following conclu-
sions from them : —

1st. The determinations hitherto arrived at respecting the quan-
tity of ammonia contained in the air have given too large results ;
for the differences between the analyses are so great, that it is im-
possible to attribute them to a change in the composition of the
air, unless the change has been accidentally produced and purely
local.

2nd. To determine with exactitude the quantity of ammonia con-
tained in the atmosphere, much larger quantities than have hitherto
been acted upon must be submitted to experiment. It would be

Meteorological Observations. 819

proper to operate upon at least 12,000 to 15,000 litres in order to
collect at least 10 milligrammes of platina.

3rd. The author states that, until researches have heen made on
a large scale, his experiments may serve as approximative.

If it be true that night air is richer in ammonia than the air of the
day, this fact may be explained by the phsenomena presented by the
nutrition of plants, by the circumstance that the ammonia which
accumulates in the air during the day and during the night is dis-
solved and precipitated by the dew at sun-rise. — Ibid. Juin 1849.

METEOROLOGICAL OBSERVATIONS FOR AUG. 1849.

Chiswick. — August 1. Very fine : clear. 2. Very fine : slight rain, 8. Slight
rain : overcast : cold at night. 4. Clear and fine. 5. Fine : cloudy. 6. Cloud-
less: very fine. 7. Fine : overcast : rain. 8. Clear : very fine : lightning. 9.
Foggy : very fine : heavy showers. 10. Hazy: very fine ; clear. 11. Clear:
cloudy: rain. 12. Overcast : clear : rain. 13. Showery. 14. Cloudy and fine.
15. Very fine. 16. Showery : very clear at night. 17 — 19. Fine. 20, Cloudy.
21 — 23, Very fine, 24. Very fine : hazy. 25. Uniformly overcast: very fine.

26, 27. Very fine, 28. Very fine : slight rain at night. 29. Overcast. 30.
Dry haze : rain at night. SI. Hazy : cloudy and fine.

Mean temperature of the month 62°*91

Mean temperature of Aug. 1848 58 '74

Mean temperature of Aug. for the last twenty-three years 62 '18
Average amount of rain in August 2*41 inches.

Boston. — Aug. 1. Fine. 2. Fine : rain p.m. 3, Cloudy. 4. Fine, 5 — 7.
Cloudy. 8. Cloudy : rain early a.m.: thermometer 79° 3 p.m. 9. Fine : rain
P.M. 10, 11, Cloudy : rain p,m, 12. Fine. 13. Cloudy : rain p.m. 14. Cloudy.
15. Fine. 16. Cloudy. 17, Fine, 18, Cloudy: rain a.m. 19. Fine. 20 —
23. Cloudy. 24— 26. Fine. 27— 29. Cloudy, SO. Cloudy: rain p.m. 31. Fine.

Applegarth Manse, Dumfries -shire. — Aug, 1. Fair. 2, 3, Fair : a few drops p.m.
4. Fair and warm. 5,6. Fair: warm : cloudy p.m. 7. Frequent showers. 8.
Fair and fine : beautiful day. 9. Very warm : thunder: showers. 10. Heavy
shower : very warm. 1 1, Very heavy rain : thunder. 12. Rain : river flooded.
13. Heavy rain. 14, Showers a, m, : cloudy p,m. 15. One shower : dull and
cloudy. 16. Heavy showers : hail. 17. Wet a.m. : fine : thunder p.m. 18. Fre-
quent showers. 19. Fair: calm: cloudy. 20. Fair and fine. 21. Fair, but
dull and cloudy. 22. Light drizzling showers. 23. Showers frequent, not
heavy. 24. Fair, but cloudy. 25. Shower during night : cleared. 26. Showers
A.M. : fine. 27. Fair and bracing: harvest day. 28. Fair, but dull : rain p.m.
29. Fair and fine all day. 30. Rain throughout. 31. Fair and fine: dull:
cleared.

Mean temperature of the month 56°*7

Mean temperature of Aug. 1848 53 '1

Mean temperature of Aug. for the last twenty-five years ... 57 '1

Mean rain in Aug. for twenty years 3*60 inches.

Sandwich Manse, Orkney. — Aug. 1. Drizzle. 2 — 4. Drizzle : showers. 5. Fog :
cloudy. 6. Fog. 7. Cloudy. 8. Rain : fog. 9. Hazy : fog. 10. Hazy:
cloudy. 11. Cloudy : rain. 12. Clear : clear, aurora. 13. Bright : clear. 14.
Drizzle : rain. 15. Clear. 16. Bright : cloudy, 17, Showers, 18. Bright:
cloudy a.m. 19. Damp: cloudy. 20. Drizzle: damp, 21. Rain : fine. 22.
Rain : clear. 23. Clear. 24. Clear : cloudy, 25. Kain. 26. Bright : showers.

27. Bright : cloudy. 28. Cloudy : showers. 29. Drizzle : damp. 30. Bright :
damp. 31, Clear : fine.

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I

THE
LONDON, EDINBURGH and DUBLIN

PHILOSOPHICAL MAGAZINE

AND

JOURNAL OF SCIENCE.

[THIRD SERIES.]

NOVEMBER 1849.

XLI. On the Notation of Crystals.
By Edward J, Chapman, Esq.*

IT may be fairly assumed that an efficient system of crystal-
lographic notation should comprise the following essential
points, — simplicity, brevity, and capability of being verbally
expressed. It should be sufficiently simple as to be retained
and applied with the slightest possible effort of the memory,
and sufficiently brief as to admit of being placed upon the
usual drawings of crystals. The symbols, moreover, of which
it is composed, should be so constituted as to be readily con-
vertible into ordinary language.

There can be but one opinion as to the necessity of the first
of these conditions, even if the utility of the two latter be
questioned. It is, however, very desirable, especially for those
who are studying the science, that the second condition should
also be fulfilled ; for, by the arbitrary and irregular lettering
of crystals, much trouble and chance of misconception is ob-
viously occasioned to the student — sometimes one, and some-
times another letter, being employed to designate the same
kind of plane ; and that, frequently, within the compass of a
few pages. The importance, furthermore, of the third con-
dition is so great, that the little attention which seems hitherto
to have been paid to it is much to be wondered at. In ad-
dressing a class, amongst numerous other instances, it is ab-
solutely essential that the notation should be a verbal one.

Of all the systems at present in use, that of Levy and Du-
frenoy can alone be said to embody the above desiderata; but
its merit in this respect is, on the other hand, marred by the
following objections, which form a serious drawback to its
adoption. In the first place, totally different planes in the
same crystallographic group are frequently denoted by a

* Communicated by the Author.
Phil. Mag. S. 3. Vol. 35. No. 237. Nov. 1849. Y

322 Mr. E. J. Chapman on the Notation of Crystals.

common symbol. In the Monometric or regular system, for
instance, the sign a^ expresses both the planes of the octahe-
dron and the cube; and the " primary form," often an arbi-
trary one, must be stated before we can determine to \ihich
solid the symbol is intended to apply. The sign i^, again, in
the same system, may denote either the planes of the rhombic
dodecahedron, or those of a particular leucitoid, or even of
the cube. The only method of avoiding this imperfection is
by the arbitrary assumption of one primary form for the entire
group ; but this, which is literally done by the German school,
is so manifest a contortion of nature to convenience, that the
French mineralogists have wisely rejected its employment.
Another disadvantage in the system of Levy and Dufrenoy, is
the non-recognition of the important bearings which the dif-
ferent crystallographic axes have on the study of the science ;
at least, these axes play no part in their notation.

In this particular the German systems possess an undoubted
superiority ; but the employment of arbitrary and often hypo-
thetical primary or fundamental forms renders them objection-
able. Their practical application, moreover, is by no means
free from diflticulty and inconvenience; for even the abbre-
viated system of Naumann is not sufficiently brief to allow of
the symbols being placed upon the ordinary figures of cry-
stals; neither can it be communicated verbally with any ease.
That it possesses great uniformity no one can deny; but
it may be questioned whether this very uniformity do not
occasion an unnecessary effort to the memory, in the recogni-
tion of the designated planes. Dana, who adopts Naumann's
system, has been forced, in the lettering of his crystals, to
ntake use of another method ; but this, although ingenious, is
not exact enough for the purposes of notation — Tor which,
indeed, it was never intended by its author, — nor can it be
verbally employed. I need not extend these observations by
referring to the works, however meritorious, of Professor
Miller, Mr. Griffin, and various other authors; because in
no one case are the three essential points, indicated above,
fulfilled ; owing either to the length, or to the peculiar con-
struction of the notations*. For these reasons I have at-
tempted to frame a system which shall serve both for the let-

* These remarks will, I am sure, be received in the spirit in which they
are made ; for, in the words of one to whose researches crystallography
first owed its rank as a science, " la critique, iorsqu'eile est juste et mo-
deree,loin d'alterer I'estiniequesedoivent reciproqueraent ceuxqui courent
la uieme carriere, ne fait que les exciter a de nouveaux efforts. Une telle
critique ne dephiit jamais qu'a des esprits superficiels, ou gates par les
6Joges outrt's de leurs contemporains.'' — Royn^ de I'Isle, Cristallographie,
<5"c., vol. i. p. xxiii (second edition), 1783.

Mr. E. J. Chapman on the Notation of Crystals. 323

tering and for the notation of crystals, in comprising strictly
the separate conditions of accuracy, simplicity, brevity, and
capability of being verbally expressed. The proposed method
is based entirely upon the position and relations of planes to
iheir crystallographic axes, and has no dependence upon the
external conjiguration of any fundamental form. The various
planes are also denoted by a few individual letters, so chosen
as to assist the memory ; and not by the position of certain
signs placed before, above, or around, a single letter, as in
the system of Naumann. The advantages which accrue from
this arrangement will, I think, be seen as we proceed.

All crystallographic planes may be included under the
terms of prismatic and pyramidal ; the latter comprising
closed forms*, and, with the exception of the basal planes
of the oblique systems, all inclined summit-planes.

Prismatic planes I designate by consonants-, pyramidal
PLANES by vovoels'X. Prismatic planes may be either monaxial
(cutting one axis), or diaxial, and in one system triaxial.
Pyramidal planes may be either diaxial, triaxial, or tetraxial
— the latter, of course, only in the hexagonal system.

Monaxial prismatic planes may be of three principal kinds,
according to the system of crystallization. In the monometric
or regular system they are of one kind, and are lettered P.
In the dimetric or pyramidal system, they are of two kinds:
so that the letter P (from irlva^, table, as in Naumann's
Basische Pinakoid) is retained to designate the basal planes,
or those which cut the vertical axis ; and the letter M (from
yi,ovo<i) is employed for the vertical planes. Finally, in the
other systems we have P for the basal, M for the front and
back vertical, and L for the lateral or side vertical planes,
which cut but one axis.

Diaxial prismatic planes are of one kind in the dimetric,
hexagonal, trimetric (rhombic), and monoclinic (oblique rhom-
bic) systems; and, as such, are lettered D (from 81?, tiao). In
the triclinic system they are of two kinds, U and B ibis, two),
the respective positions of which will be shown further on.
Triaxial prismatic planes can be only met with in the hexa-
gonal system : they are lettered T.

The following symbols are consequently sufficient to denote

all kinds of prismatic planes: — P; M; L; D; B; and T;

* The cube omitted.

t This idea is derived from Haiiy's method of designating planes on pri-
mary edges by consonants, and those on angles by vowels j but it must be
borne in mind that many inclined summit-planes are by this method denoted
by consonants, for the two systems are fundamentally quite distinct.

Y2

324 Mr. E. J. Chapman on the Notation of Crystals.

although of D and B various series may occur, as D^, D|,
D, D2, D3, &c. To this, however, we shall revert as we
proceed.

Diaxial pyramidal planes are of one kind in the monome-
tric, dimetric, and hexagonal systems, and are lettered A. In
the trimetric or rhombic system they are of two kinds, denoted
respectively by A and E ; the former being situated in front
when the crystals are in position, and the latter at the sides,
or upon the acute angles of the rhombic prisms. A is there-
fore associated in position with the prismatic planes M, and
E with L. In the monoclinic system the diaxial pyramidal
planes are of three kinds — A, E, and I. The planes E, in
sets of four, are situated at the sides ; A is the front plane at
the top of the crystal, and the back plane below ; I is opposed
to A. Finally, the triclinic system possesses four distinct sets
of diaxial pyramidal planes: — A, A A, E, EE. These are,
however, common to but few minerals ; and they are very
rarely, if ever, all present at the same time.

Triaxial pyramidal planes are of one kind in the mono-
metric, dimetric, hexagonal, and trimetric systems, and are
designated by the symbol O. In the monoclinic system they
are of two kinds, O and U ; the former being situated in the
principal position, that is to say, in front and above. The
planes U are therefore the upper planes behind, and the lower
planes in front. Lastly, in the triclinic system, these planes
may be of four kinds : — O, OO, U and W — but they rarely
occur together in the same crystal.

The tetraxial planes of the hexagonal system are of one
kind, and are lettered Y.

Pyramidal planes are consequently denoted by

A; E; I; A A; EE; O, U, OO, W; and Y;
of all of which various series may occur, but more especially
of A, E, I, O, U, and Y ; as, J^O, |0, ^O, lO, O, 20, 30, &c.
The relations and notation of these different planes are
exhibited more distinctly in the following table ; by which it
will be perceived, that by the enunciation of a single letter,
the position of the designated plane is immediately called up
before us : because, by this letter, we know at once whether
the plane be a prismatic or a pyramidal one ; and furthermore,
the number of axes which ft cuts, and consequently its po-
sition.

Mr. E. J. Chapman on the Notation of Crystals. 325

Prismatic Planes.

Pyramidal Planes.

Monaxial
Diaxial
Triaxial
Tetraxial

P; M; L.

D, Di,D»i; B,Bi Bm.

T

A,iA,wA;E,^E,mE; I.^I.ml; AA,EE.
0, ^0,niO; U, 'U.jmU; OO; W.
Y,iY.mY.

It is, however, necessary, for the complete elucidation of the
proposed method,to examine separately the notation appertain-
ing to each crystallographic group. In the following scheme
numbers greater than unity are represented by m or n, and
those less than unity by ^. Placed before a letter, these refer
to the vertical axis ; and when placed after a letter, to one of
the other axes, as will be explained in the observations at-
tached to each system.

Monometric System,

Monaxial form : —
The cube, P.

Diaxial forms : —

The rhombic dodecahedron, A.
Tetratrishexahedrons, -A.

' m

Triaxial forms : —
The regular octahedron, O.
Leucitoidsoricositetrahedrons,-0.

' m

Trisoctahedrons, mO.
Hexakis-octahedrons, mOn.

Fig. 1.^

Copper : Siberia.
Fig. 2.

O

Regular tetrahedron.
Other hemihedral forms, designated
after a similar manner, =-.

Galena: Clausthal.
Observations. — In the less simple forms of this system, that

* For several of these examples I am indebted to the beautifully executed
plates of Dufrenoy's Atlas, Traite de Mineralogie, 1846. I have, however,
added the axes to each figure, so as to render the positions of the different
planes more readily apparent.

326 Mr. E, J. Chapman on the 'Notation of Crystals.

face has been chosen for the basis of the notation which cuts
the horizontal axes, for the time being, at equal distances; so
that, with the exception of the hexakis-octahedrons, in which
a single face of this kind does not occur, these horizontal axes
may always be considered unity. The symbol of the leuci-
toids becomes thus -O. and that of the trisoctahedrons mO.

The hexakis-octahedrons form the intermediate planes i of
the French crystallographers ; and as in the combinations in
which they occur these planes are usually subordinate to the
others, their necessarily small size in drawings often prevents
the complete symbol, which is exactly similar to that of Nau-
mann, from being employed in their lettering; for which
reason any conventional sign may be used for that purpose,
and the exact notation placed beneath the figure : as, " or
# = 204, &c.

Fiir. 3.

Dimetric System.

Monaxial Planes : —
Basal planes, P.
Vertical planes, M.

Diaxial Prismatic Planes : —

Vertical planes alternating in position with
those of the ordinary square prisms, D.
Ditetragonal prisms, T>m.

Diaxial Pyramidal Planes : —

Ordinary square-based octahedrons. A,

iA, wA.

Triaxial Planes : —

Octahedral planes alternating in position

with the above, O, -O, mO.
Dioctahedrons, mOn.

Zircon : Frederiksvarn.

Observations. — In this system, and in those which follow, a
fundamental form must be chosen for each mineral as in the
usual notations, but with this difference : that whereas the
German crystallographers choose invariably pyramidal forms
for this purpose, often quite opposed to the crystallization of

Apophyllite: Faroe-
Fiji. 4.

Mr. E. J. Chapman on the Notation of Crystals. 2>Tl

the mineral, if not altogether hypothetical, I would select that
form most in keeping with the prevailing character of the
crystallization ; and therefore, sometimes an octahedron with
Weiss and his disciples, and sometimes a prism with Levy
and Dufreiioy. It would, however, be still better, as the pro-
posed notation, unlike those of the above crystallographers,
has no dependence upon the actual external shape of the fun-
damental form, to name merely the relative lengths of the
axes, thus: protaxialform =-756 X(idocrase); or '55^ ^'950,
&c., the value before the symbol to be considered the relative
length of the vertical axis, and that after the symbol to refer
to one of the lateral axes, the other axis being unity. The
protaxial forms of the different systems would be then as fol-
lows:— monometric system, X; dimetricand hexagonal systems,
^X ; other sj'stems, xlLx. In the inclined systems the incli-
nations of the axes should of course also be given.

Hexagonal System.

Monaxial Planes : —
The basal planes, P.

Biaxial Prismatic Planes : —

Vertical planes of ordinary hexagonal
prisms, D.

Triaxial Prismatic Planes : —
Vertical planes alternating in position
with the above, T.

Triaxial Pyramidal Planes : —

Ordinary hexagonal pyramids, O,
iO, mO.

m

Tetraxial Planes : —

Hexagonal pyramids alternating in position with the above,

Y, iY, mY.
Dihexagonal pyramids, xYm^ w = .rY4-2, —2.

Apatite : Zillerthal.

Hemihedral Forms'.
Rhombohedrons,

O iO mO

' 2' 2
xYmn

——- ; or conventionally, R.

Scalenohedrons, — - — ; or xrx^\ or, in general, simply

•^S. In the conventional symbol of these forms, the sign r=:
Uie inscribed rhombohedron ; and as this is very generally
the same as the fundamental rhombohedron, the notation
becomes merely .rS, and is then, I think, more significative

328 Mr. E. J, Chapman on the Notation of Crystals.

than Naumann's symbol of R'. Scalenohedrons, however,
are not possessed by more than five or six minerals, and are
only abundant in one, — calcareous spar.

Observations. — Rhombohedrons being the more common
fundamental forms of this group, Naumann adopts two kindred
systems for the notation of the derived forms ; one starting
with the hexagonal pyramid .rP, and the other with the rhom-
bohedron xK^ each producing a similar series : — OP, c» P,
GO Poo, — OR, 00 R, ooRoo, &c. It is however evident, that
in the proposed notation only one series can y\q. q,

result, whatever be the fundamental form ;
for R and S are the only arbitrary symbols ;
and their employment, in rendering the no-
tation more simple, does not in any way
affect the other signs. The triaxial pris-
matic planes T should be strictly T2, 2 ; but
the figures are quite unnecessary, for these
planes being tangents to one of the horizon-
tal axes, it is obvious — the axes crossing
each other at 60° — that the other two must
be cut at twice the distance. The values also
of m and n in the dihexagonal pyramids can
only equal -|-2, — 2, as otherwise the form Y
would result.

C ale-spar :
Cumberland.

Fig. 7.

Trimetric System.

Monaxial Planes: —
Basal planes, P.

Back and front vertical planes, M.
Side vertical planes, L.

Diaxial Prismatic Planes : —

Vertical planes of ordinary rhombic
prisms, D, D^, Tim.

Diaxial Pyramidal Planes : —

Inclined planes cutting the shorter

horizontal, or frontal axis, A, ^ A,

TwA.
Inclined planes cutting the longer

horizontal, or right and left axis,

E, -^E, wE.

'to '

Triaxial Planes : —
Ordinary rhombic octahedrons, O,

iO, mO.
Intermediate planes, xOx. Scorodite : Brazil.

Epistilbite: Faroe.
Fiff. 8.

Fig. 9.

Mr. E. J. Chapman on the Notation of Crystals. 329

Observations. — In this system, in accordance with the ge-
neral custom, the longer horizontal axis is considered unity.
The planes A^, A^, &c. of the rhombic prisms of Levy and Du-
fr^noy correspond therefore to the planes D^ of the present
notation, because they abut more immediately upon the shorter
axis. The planes g\ ^, &c., on the other hand, are equiva-
lent to Dot. a value following a letter, invariably refers to
the relative length of the shorter horizontal axis compared to
that of the longer one as unity. Nauraann's symbols are, for

D-, 00 P«; and for Dm, ocP«.

The monaxial planes M and L form the vertical faces of
rectangular prisms ; whilst the biaxial pyramidal planes, j?A
and ajE, produce rectangular octahedrons.

Monoclinic System.
Monaxial Planes : —
Basal planes, P.

Back and front prismatic planes, M.
Right and left prismatic planes, L.

Diaxial Prismatic Planes : —

Ordinary oblique rhombic prisms,
D, D-, Dot.

' to'

Diaxial Pyramidal Planes : —

Upper inclined planes in front, or

lower behind. A, ^A, mA.
Upper inclined planes behind, or lower in front, I, ^I, wil.
Inclined planes at the sides, E, -E, wiE.

Triaxial Pyramidal Planes : —

Upper frontal planes of oblique rhombic octahedrons, or
lower back planes of the same, O, ^O, mO.

Upper back planes of oblique rhombic octahedrons, or lower
planes in front of the same, U, ;|jU, mU.

Intermediate planes, xOx ; x\5x.

Observations. — In this system the orthodiagonal or horizontal
axis is made unity ; for if the clinodiagonal be selected as such,
according to perhaps the more usual custom, the positions of
the planes D^ and Dm will be the reverse of what they are in
the preceding system. By making, however, in each system
that axis unity which passes from left to right, the crystals
being in position, those planes which abut the more imme-
diately upon the frontal axis will invariably have the symbol
Di.

330 Mr. E. J. Chapman 07i the Notation of Crystals.

Fiff. 10.

Tri clinic System.

Monaxial Planes : —

P — M — L, as in the preceding
system.

Di axial Prismatic Planes : —
B-B^; iy-T>x.

Diaxial Pyramidal Planes : —
A; AA; E; EE: with their va-
lues K m, as above.

TO' '

Triaxial Pyramidal Planes : —
O; OO; U; W; with their va-
lues -, m.

In conclusion, we will tabulate the proposed notation, for
the sake of reference, with those of Weiss and Rose, Nau-
mann. Levy and Dufrenoy, and Mr. Griffin. It should be
observed, however, that the latter author adopts throughout
each crystallographic group one uniform system of three rec-
tangular axes, differing only in regard to their relativelengths*.
In the following tables the forms are arranged in accordance
with the number of axes which they cut, monaxial forms
being placed first.

Monometric System.

: E.i.c.

Weiss and
Kose.

Nau-
mann.

Ldvj' and Dufrenoy.
P. F. the cube.

Griffin.

P

a : oca : oca

odOqo

P

P, M, T.

A

a : a: oca

ooO

b'

MT. PM.PT.

iA

a : ma : coa

ooOw

b'"

M-T,M-hT.P-M,P+M,P-T

P+T

0

a:a:a

0

a'

PMT.

^0

a:a:^

mOm

„m

3P-MT.

j»0

a: a: ma

viO

1

am

3P-hMT.

mOn

1 1

mOn

»(=i'6'"i»)

6P-MT.

* System of Crystallography, with its Applications to Mineralogy. 1841.

Mr. E. J. Chapman on the Notation of Crystals. 331

Dimetric System.

E.I.C.
P

Weiss and Rose.

Naumann.

Wvy and Dufir^noy.
P. F. a square prism.

Griffin.

oca : <xa : c

OP

P

P

M

aoa : a: coc

ooPx

M

M; T

D

a la-.ccc

ooP

h'

MT

Dm

a -.na: ccc

C»P«

A"*

M-T, M + T

A

a : ooa : c

Px

V

]

^A

a : ooa : ic

nP»

b-"

>PxM, PxT

mk

a : oca : vie

»iP»

b"'

J

0

a:a: c

P

a'

1

\P

a:a: —c

«P

a'"

^Pj:MT

mO

a:a: vie

mP

am

J

tnOn

a'.naxmc

mPn

i(=A'i™A«)

PxMj/Tz . PxMzTy

Hexago

nal System.

E.I.C.

Weiss and Rose.

Nau-
mann,

L^vy and Dufr^noy.
P.F.'hezagonal prism.

Griffin.

P

ooa : oca : ooa : c

OP

P

P

D

a: a: ooa : <x>c

ocP

M

M, M2Ti^

T

2a : a : 2a : aoc

ooP2

h'

T, Mif T2

O

a :a: ooa : c

P

b' 1

^0
mO

a '. a : <xa : mc

«P

1

b7n J

P,rM,P,rM2TH

Y

2a:a:2a'.c

P2

a' 1

mY

2a:ai 2a:mc

nP2

a""
i

a»i

PxT,VxMUT2

xYx, X

a ', na '. pa ', mc

xPm,n

Sim 1,2m fix

3px my <«

x\l

r ^(a : a : ooa : mc) •]
l^(a': a': ooa : Twc) J

xR

-■:

Rx

xrxS

•\\{a:na:pa:mc) •]
J ^(a' : na' : pa : mc) J

xR'

Sx

332 Mr. E. J. Chapman on the Notation of Crystals,
Trimetric System,

E.I.C.

Weiss and Rose.

Naumaun.

li^vy and Dufr^noy.

P.F. a rectangular

prism*.

Griffin.

P

M
L
D

D^

Dm

A

mk

E

lE

m

ntE
O

ho

mO
xOx

ooa : Oib : c
a:<x>b: ooc

ooa : b : ooe
a:b:<x>c

a

]■
}

mb : CDC
a :ccb : c
: ooA : mc
ooa ibic
<x>a : b : mc
a:b ic
:b:mc
ma:itb : c

OP
00 Poo

w

ooPoo
ooP
ooPw
00 Pn
Poo

jmPoo

Poo

jmP»

p

jmP
mPn

P
M
T

h'
A»
A-
b'

\_

A""

t, j', 4'c.

P
M
T

MorT

P.rM

P*T

Pjr My Tz

Mojioclinic System.

E.I.C.

Weiss and Rose.

Naumann.

L^vy and Dufr^noy.
P.F. an oblique rhom-
bic prism.

Griffin.

P

ooa : ooi : c

OP

P

iPi;M

M

a : od5 : ooc

OoPoD

A'

M

L

ooa : A : ooc

[ooPoo]

«'

T

D

a : A : ODc

ooP

M 1

D^

a : »mA : ooc

HhooPra

A" V

MxT

Dm

jwa : A : ODC

[± ofPw]

r J

A

o : oo5 : c

-Poo

o' 1

^A
toA

I a : ooi : »ic

— mPoo

{ I }

iP*M, Zn.

* If a right rhombic prism be chosen as the primary form, M in the
proposed notation will equal A'; L, g'; D, M; D^i A"; D»», g*"; A, a';
E,e'; and 0,b'.

Mr. E. J. Chapman on the Notation of Crystals. 333
MonocUnic System (continued).

E.I.C.

Weiss and Rose.

Naumann.

li^vy and Dufr^noy

?.F. an oblique rhoin

bic prism.

GrifiSn.

I

a' :cx>b:c

+ Poo

a'

ml

I a' -.(Xib-.mc

+»/Poo

r a™ \ iPj-M, Zs

i i J

E

ooa :b:c

+ LPQO]

e' -j

IE
mE

• (X>a: b :mc

+[»jPoo;

{ 5 J

^ ^PxT.ZeorZw

O

aibic

-p

d'

mO

I a: b :mc

-m?

{ ^^ J

^ ^Pj:Mj/T«,Zne
or Znw

U

a'lb'.c

+P

6'

I a' :b: mc

+ JWP

r A""
1 ^" -

|Pa-%Tz,Zse
or Zsw

xOx

ma :nb:c

—mFn

i,^c.

x\Jx

ma' :nb: c

4-7wPra

i,8fc.

1

Triclinic System.

E.I.C.

Weiss and Rose.

Naumann.

L6vy and Dufr^noy.

P.F. pr. obi. non

sym^trique.

Griffin.

P

oca : oab : c

OP

P

^FxMyTz

M

a : cub : ooc

ooPoo

M

M

L

ooa : i : Qcc

w

ooPoo

T

T

B

a : i' : Qoc

oo'P

g'

iMj:T, nw.

D

a : A : ooc

ooP'

A'

|M*T, ne.

A

a : Qob : c

'P'oo

d'

AA

a! :cDb :c

/P.«

c'*

E

EE
0

ooa : b' : c

ooa :b : c

a-.b'.c

'Fqo

.p,«.

'P

4'

|Pa: My Tz,the in-
dividual plane
being determined
by the zone.

00

a : b : c

P'

o'

U

a'.b-.c

P/

a'

W

a':b':c

,p

»' ^

* In Dufrenoy's primary form, the plane c'is sometimes made an upper
back plane, and at other times an upper front one. When the latter is the
case, as in his figures of albite {Traits de Min., Atlas, pi. 166 to 171)» '^ will
equal A, and d AA, of the proposed notation.

[ 334. ]

XL II. On a peculiar Fibre of Cotton which is incapable of
being Dyed. By Walter Crum, Esq., F.R.S., Vice-Pre-
sident of the Philosophical Society of Glasgow^.

IN the month of May last, Mr. Thomson of Primrose re-
ceived from Mr. Daniel Koechlin of Mulhansen some
specimens of a purple ground printed calico, each of them
containing a portion of cotton which was white, although sub-
jected to the same treatment by which the rest of the cloth,
and even the threads which crossed the white one, was uni-
formly dyed. The white part of the thread was usually thicker
than the rest, and little more than a quarter of an inch long.
The whole fabric had been thoroughly bleached before print-
ing, so that it contained no grease or other impurity that could
resist the colouring matter.

White specks like these are not unknown or undreaded
among the printers of calicoes in this country. M. Koechlin
mentions that the cotton of which they are formed is known
by the name of colon mort, and here also it is called dead
cotton. M. Koechlin has been the first, I believe, to suggest
that it may consist of unripe cotton, and that its fibre may be
solid, wanting the hollow of the more perfect fibre. He adds,
that if such should prove to be the case, its behaviour with co-
louring matters may affect materially the question of the me-
chanical or chemical nature of the union of cotton with its dye.
Mr. Thomson did me the honour to transmit me the speci-
mens for examination.

The ordinary cotton fibre, it will be remembered, is de-
scribed by Mr. Thomson in the memoir where its form was
first made known f, as a tube, originally cylindrical, but which
collapses in drying. It has then the appearance of two small
tubes joined together, so that a transverse section of the fila-
ment resembles in some degree a figure of 8. Until full ma-
turity the cylinder is distended with water, in which bubbles
of air are often distinguishable.

On placing a few of the fibres of the colon mort under
the microscope, I found them to consist of very thin and re-
markably transparent blades, some of which are marked or
spotted, while others are so clear as to be almost invisible
except at the edges. These fibres are readily distinguished
from those of ordinary cotton by their perfect flatness, without
the vestige of a cavity, even at the sides, and by their uniform

* From the Proceedings of the Philosophical Society of Glasgow, 1848-
49, and read before that Society April 25, 1 849.

t Annals of Philoso[)hy for June 1834. Lately reprinted in the Classical
Museum, No. 20; and in Liebig's Annalen for January 1849.

Mr. W. Crum on a peculiar Fibre of Cotton. 335

as well as great transparency. They are often broader, too,
than the usual fibre, and they show numerous folds, both lon-
gitudinal and transverse; but they are never twisted into the
corkscrew form of the ordinary fibre.

It occurred to me that cotton of this description might be
detected among the wool as it is imported. I searched ac-
cordingly for any portions that had a different appearance
from the rest; and having collected and examined them, I
found one sort whose filaments had exactly the appearance
under the microscope of the coton mort in the pattern of M.
Koechlin. It occurs in the form of a small matted tuft of a
shining silky lustre, and usually contains in its centre the
fragment of a seed, or perhaps an abortive seed. It consists
of short fibres having litde tenacity. Specimens of it are
found in abundance among the motes or hard portions, called
droppings, rejected by the picking machine in the preparation
for spinning. Small tufts of it, however, do occasionally pass
the sifting process of the picking machine; and then, their
fibres being too short to be teazed out in the carding engine,
or drawn into threads in the subsequent operations of cotton
spinning, remain as minute lumps or knots upon the threads
of better wool.

Although the microscopic appearance of the fibre in ques-
tion is that of a flat single blade, the cellular character of the
tissue scarcely admits of such a formation. We must rather
suppose that, like the healthy unripe cotton fibre, it was ori-
ginally an elongated cell or tube filled with liquid ; that the
seed around which it began to grow had died soon after its
formation, while the fibres which clothed it were yet soft and
pliable ; and that the flattening, and perhaps growing together
of the sides of the tube, was occasioned by the pressure from
the increasing crop of cotton attached to the numerous other
seeds confined in the same pod.

To explain the bearing of this peculiar structure upon the
question whether cotton wool and colouring matters form
together a true chemical compound, or are held together by
a merely mechanical power, I must quote a passage from a
memoir on this subject which I read to the Philosophical
Society six years ago, and refer to the memoir itself for addi-
tional illustrations.

" In many of the operations of dyeing and calico-printing,
the mineral basis of the colour is applied to the cotton in a
state of solution in a volatile acid. This solution is allowed
to dry upon the cloth, and in a short time the salt is decom-
posed, just as it woukl be, in similar circumstances, without
the intervention of cotton. During the decomposition of the

SS6 Mr. W. Crum on a peculiar Fibre of Cotton.

salt its acid escapes, and the metallic oxide adheres to the
fibre so firmly as to resist the action of water applied to it with
some violence. In this way does acetate of alumina act ; and,
nearly in the same manner, acetate of iron. The action here
can only be mechanical on the part of the cotton ; and the
adherence, as I shall endeavour to show, confined to the in-
terior of the tubes of which wools consist, or of the invisible
passages which lead to it. The metallic oxide permeates these
tubes in a state of solution ; and it is only when its salt is
there decomposed, and the oxide precipitated and reduced to
an insoluble powder, that it is prevented from returning
through the fine filter in which it is then enclosed.

" When the piece of cotton, which, in this view, consists of
bags lined inside with a metallic oxide, is subsequently dyed
with madder or logwood, and becomes thereby red or black,
the action is purely one of chemical attraction between the
mineral in the cloth and the organic matter in the dye-vessel,
which, together, form the red or black compound that results ;
and there is no peculiarity of a chemical nature, from the
mineral constituent being previously connected with the cotton."

To produce the purple dye of M. Koechlin's pattern, the
cloth has first to be impregnated with iron. For this purpose
it is made to imbibe a weak solution of proto-acetate of iron,
and afterwards dried. By exposure to the air for some days
the salt is decomposed. Its acetic acid evaporates, and the
oxide of iron, then become peroxide, remains in the fibre.
The cloth is afterwards subjected to severe washings in hot
and cold water, but its iron is not removed ; and the question
is. How is it retained in connexion with the cotton ? Mecha-
nically, as I maintain, and probably in the interior of its hollow
fibre, which it entered in a state of solution, and within which
it was precipitated. Others, as I have already stated, are of
opinion, after Bergman, that the combination is a chemical
one ; and so fully is that view carried out by my friend Pro-
fessor Runge of Oranienburg, in his ingenious and excellent
work on the Chemistry of Dyeing*, that he assumes coloured
cottons to be combinations of what he calls cottonic acid with
the various bases, in definite, and even in multiple proportions.
Thus a very pale shade of buff from oxide of iron is called
percottonate of iron ', a.no\hev \s c&WqA bicottonate of iron \ and
still deeper shades, cottonate and basic cottonate of iron.

But the new fibre, by the same treatment, is incapable of

retaining the iron mordant, and yet both fibres have the same

chemical composition and the same ultimate structure. The

only difference is, that one is shaped into tubes or bags capable

♦ Farbenchemie. 2 vols. Berlin, 1832 and 1845.

Mr. W. Crum on a peculiar Fibre of Cotton. 337

of holding all matters which are insoluble in water, that is, all
bodies which can be caught upon a filter, while the other is
possessed of no such enclosure.

I take this opportunity, in reply to a review of my first
memoir on this subject, by M. Persoz, in his remarkable work
Traitt de V Impression des Tissus, of explaining that I attribute
to an attraction of surface those cases of dyeing where pure
cotton, by mere immersion, is enabled to decompose the solid
matters in solution, and to withdraw them from the solvent.
Such is the case with the solution of deoxidized indigo in
lime, with the plumbite of lime, with the various salts of tin,
and many other solutions. Cotton, as I have stated, acts in
these cases like charcoal and other porous bodies, and I have
seen no reason to confine the attraction in question to the
internal surface of the cotton fibre.

But I have not ranked the aluminous mordant among the
class of bodies so attracted ; because cotton, when immersed
in a solution of acetate of alumina, has not the power of sepa-
rating its base. That solution must be applied to cotton and
dried in it; and then the alumina only atllieres, or loses the
power of being washed away, in proportion as the acetic acid
is removed by evaporation. I could see here no chemical
decomposition effected by the cotton wool, for the same salt
may be decomposed by evaporation in a glass vessel. In this
case I have represented the alumina as being held in the inte-
rior of the fibre, just as sand may be held in a bag whose in-
terstices are too narrow to allow its particles to pass.

M. Persoz has remarked, however, that by evaporating a
solution of acetate of alumina in a glass vessel we do not so
thoroughly decompose it as by drying the same substance
upon calico. This I also have observed ; and although I have
been accustomed to ascribe the difference to the more exten-
sive division and exposure of the salt upon cotton, I have no
proof, and shall not deny, that the presence of cotton at a
particular stage of the evaporation may accelerate the decom-
position of the salt, and that its fibres may thus attract a portion
of alumina over their whole surface. If this modification of
the view I had given be correct, the action of the coton mart
proves at least that colouring matter adhering outside is not
so permanent as that which is held within the fibre of the
mature cotton.

Neither view gives any countenance to the chemical theory.
Porous bodies are well known to attract, and even to decom-
pose, without chemically combining with the substances they

Phil. Mag. S. 3. Vol. 35. No. 237. Nov. 1849. Z

338 The Rev. Brice Bronwin on the Theoty of the Tides.

precipitate. Accordingly, none of the oxides are changed
either in colour or in chemical character by their union with
cotton. The hydrated oxide of copper, for example, precipi-
tated upon calico, becomes carbonate, or arsenite, when ex-
posed to carbonic or arsenious acid. The protoxide of iron
changes speedily in the air into the red sesquioxide, and that
again may be converted into prussian blue, or into a black or
purple lake — every new compound, if it only be insoluble,
adhering firmly to the wool.

XLIII. 0?i the Theory of the Tides.

By the Rev. Brice Bronwin.

[Concluded from p. 270.]

IF we now take account of a second planet, marking the
quantities relative to it with an accent, we have

3/=F2Cos 2((p-/32) + F'acos 2(<p'-^'2) + Fi cos (f-/3,)

+ F'iCos(^'-/3\).

But Fi cos (<p — /3i) + F'j cos (<p'— /S'^) is very small in our seas,
and perhaps generally so ; therefore, neglecting it,

y-Y^Qos 2{f-3^) + F'gcos ^{(p'-^'^).

We cannot affirm that (S'g is exactly equal to /Sg, though we
may suppose their diiference to be very small. Make

or

then

i/ = F2Cos2(f'-/3'2-A) + F'2Cos2(<p'-/3'2).

^ =- (2;,'n-2^)F,sin2(9'-^',-A)-2p'nF,sin2(^'-/3g

+ ^^cos2(^'-/3',-A)+ ^cos2(^'-/3y.

If we suppose the first planet to be the sun and the second

dF . dF'

the moon, —r^ is very small compared with -j^, and may be

neglected. Moreover the variable part of FL contains only

dF'
very small quantities, and in -— ^ they will be multiplied by

dF'
the small quantity v'; we shall therefore neglect — ^. Then

dt

dij „ .
-77 = 0 gives
dt *'

The Rev. Brice Bronwin o« the Theory of the Tides. 339
I {2phi-2 ^) Fj cos 2 A + Sp'nF'g }• sin 2(^' -/S'g)

- (sy n - 2 -^ ) Fg sin 2 A cos2 ((p' - /S'^) = 0,
and

tan 2((p'— j3'2)= tan 2(n^ + CT— rj;'— ^'2)

( 2y« — 2 -7T- ) Fo sin 2A

dt )

2p'nF'2+ { 2p'«— 2 -^ j Fgcos 2A

which gives the time of high water.

If we take account of the two small terms Fj cos((p — /3j),
F'j cos (f'— /3'i), we may substitute in their diiFerentials the
value of ip' given by the preceding formula, and thus correct
it; but the correction would be too complicated for practical
purposes. Dividing the numerator and denominator by

it becomes
where

^/ f „/ V Fg sin 2A

tan2(^'-/3'2)=p,^^^p-^^^,

, rfA , JA ^ ndt
^ dt ndt

very nearly, since yw = «—cv'.
We have found

d-^—dzi 1—7; sin^ 0 cos 2a; j;

therefore, making d and o the same, since their difference is
small,

d^>^=dz'(l — ^ sin^ o cos 2^ j,

and

d{^-'\,')=dz—d^-'\s\\\^ o{dz cos 1z-dz^ cos 2^).

Also

vf/^=c?^rri — 2^ cos (^r— 7r)~);
whence

^ =y(l + 2^cos (s-tt)), -^ =v'(l + 2e'cos(5r'-7r')).

Z2

34.0 The Rev. Brice Bronwin on the Theory of the Tides.
Consequently

^(^~^^ rrv-v'-avVcos (z' -Ti') -l-sm''-o{vcos2z- v' cos2z'),
dt ^ ' 2 '

neglecting the terms containing the very small quantities ve
and - sin^ o vV.
Again, by (17.)»

^!^3zl3l = isin^ oleosa,'. ^ - cos 2^'^) -2^^cos(2-7r)
dt 2 \ dt dt; dt

dz' 1

+ 2^' -J- cos (2' — tt') = - sin^ o( v cos 22 — v' cos 2^')

+ 2vVcos (^' — w'),

neglecting the same small quantities as before. And

d{^^-^'^) ^ d{^-l^
dt dt

very nearly ; therefore

ndt ~ ndt ndt n n

very nearly. Hence we have

v'
8=1--.
n

It would be better to divide the numerator and denominator

F.
of the value of tan 2(<p'— /S'g) by Fg, and reduce -~ 8 to its

simplest form.

If we wish to make 8«; a complete variation relative to r and
■Bj, the equation of condition is, leaving out the terms contain-
ing (s) as before, these being insensible,

4- ^r^ sin^ 5 ^ + 2«r2 sin fl cos d '|^1 = - 2«r sin^ d -^.
rfr L dt^ dtj dtsdt

Make

^- =A sin/((p— ^), sinfl^ =Bcosi(f — §),

A and B being functions of r and fl without A By substitution
and dividing the result by n sin 9 sin 2(<p — ^), we have

-^ { - apr^B + 2r2 cos fl A } = 2?>B,

The Rev. Brice Bronwin on the Theory of the Tides. 341

«>;• - .- — 2r cos fl -i 1- 2i{p + 1 )B— 4 cos d A = 0. - ! ^^•

or

y 2rCOS fl — r-

(Ir dr

We shall neglect v, then 7)= 1, and the last becomes

/r-j— — 2rcos6 V-+4'«'B— 'l*cosfiA = 0. . (19.)

ar dr ^ '

To make' Iw a complete variation relative to r and 5, we
must have

Substituting for -7-5-, &c., and dividing by n cos /(ip— 5), we
find

^{ipr^k - 2r2 cos AbI- = - 2/- ^ (sin (3B,)
or

/>r-T7 — 2rcosfl -^ |-2z>A— 4 cos dB + 2 ^(sin 6B)=0.

Making ^= 1, and putting for -rr (sin SB) its value from {e\
there results
//•-^ 2r cos fl -^ + (4/— ^ sin^ n A-4 cos flB = 0. (20.)

Make ■*»'''^^

A=XCr-, B = 2Dr-. ,,t,j,.

By the substitution of these values in (19.) and (20.), we find

(w + 4)/D — (2w + 4)cos6C = 0, j

(2w + 4) cos fl/D - (i2(TO + 4) - 4 sln^ 5) C = 0. J

Eliminate p- between these, and there results

i^{m + 4)^ — (2w + 4)2 cos^ fl — (w + 4)4 sin^ fi = 0. ./

Thus (19.) and (20.) are rendered identical. Let the roots
of the last equation be m^ and ;«2> ^"^^ ^^ have

A = Cir"'i + Cg/-'''^ B = Dir"'! + D^r^'s. ^ g < r,.' ^.

When /=2, we find

4
m,= — .% w,,= r-5-7.

342 The Rev. Brice Bronwin on the Theory of the Tides,

When «=1,

4 cos^ 6
^ 1 — 4) cos^ 9

The first value of wzg is infinite negative at the pole, and the

second is so likewise when cos 6= -, or in the latitude of 30°.

2

If, therefore, r be less than unity, r'"2 is infinite at both places;
and if r be greater than unity, it is nothing. This is inad-
missible, since we can give to r any numerical value we please.
We must therefore have C2=0, D2 = 0, or the constant arbi-
traries by which the values of these quantities are multiplied
must be nothing. Thus we have

A=Cir'«i, B=:Dir'«i;
and therefore

C, or C=Ar-'««, D, or D = Br-'"i.

These values, substituted in the first of (21.), give

(m + 4.)zB — (2m + 4) cos 9 A = 0.
If by means of this we eliminate- B from the equations

^(sineA)-/B = 0, 2^(sineB)-(e2-2sin2d)A = 0,

given in the first paper, we find

. , rfA m . .

sm fl -rr cos 9 A = 0,

^^^.4(sinecos9A)-(22-2sin2a)A=0.
w + 4 </9 ^ ' ^ '

Let /=2, m= — 3 ; and both these reduce to

f /I c?A . .

sinfl-jT- +3cos6A = 0,

which, integrated, gives

A_A - ^2

This will be found upon trial to be a particular integral of (7.).

rfA
Let 2 = 1, w=0; and both the above reduce to -j^ =0,

which gives A = Ai=ai, which is also a particular integral of
(7.) in this case. These results serve to confirm the legiti-
macy of the process j and since each of the above equations
leads to the same result, the confirmation is in a manner
doubled.

The Rev. Brice Bronwin on the Theory of the Tides. 343

The other particular integral of (7.), when 2=2, found by
means of the above, is

bg cos d ,^ . o ..

SO that the complete integral is

A,= ^. + *S^»(2 + sin'«).
sm"^9 sm'^fl ^ ^

This is the form in which I first found it. But each of these
particular integrals is infinite at the pole. Make

1

2
then

The second of these particular integrals is infinite at the
pole J we must therefore make Cc^ = 0. Then

K

_ /I— cos 6 COsfl\_ ^2 / 1 -\

\^cos^2 /

/_l__X+2sin4\=a,sin4/-^+2\

(l+Scos^l),

2sind

sm-

COS"'-

2

which is also a particular integral of (7.), and the value before
given to Ag.

From (19.) and (20.) we may find equations containing A
only, or B only. By elimination and differentiation, and then
eliminating again, we shall easily find

(i2_4cos29)r2'l^ + (9i2_4-16cos2a)r^ + (16?"2-16)A = 0

(/2-4cos2fi)r2^ + (9i"2-4-16cos2fl)r^ + (l6i2-16)B = 0.

The integrals of these are obtained by assuming A = Cr'",
B=Dr'", and each of them gives the same values of wz, and
these will be found the same as those before obtained.

Suppose, for the sake of illustration, that there is only one

344- The Rev. Brice Bronwin on the Theory of the Tides.

planet to raise the water; we see from what has been done in
these papers that the passage of the planet over the meridian
and the time of high water will not necessarily coincide, and
that the retardation or acceleration of the tide is a necessary
consequence of the mathematical theory itself. Moreover, we
see tliat the retardation or acceleration is not a constant quan-
tity ; but the variable part of it is small, and may be insensible.

The four arbitraries flg' ^n ^^2» ^v which have been intro-
duced by integration, depend upon the depth of the sea, and
the form of the shores ; or, in other words, they depend upon
the closed surface of the water, and must be determined for
each particular place by observation. Hence the theory and
observation will not be at variance, as heretofore, with regard
to the height of the tide at any particular place, or in any
particular latitude, when these arbitraries are properly deter-
mined.

The variation Sco has been made a complete variation rela-
tive to the quantities 9, ot, and r; but the terms depending on
V have been neglected ; not necessarily, but for the sake of
simplicity. It is possible, Itowever, small as this quantity is,
that it might make a sensible alteration in the form at least of
the coefficients as functions of 5 ; but this is a matter of no
practical importance.

Heretofore the direct action of the planet has alone been
considered in this theory ; whereas the simple consideration
that the water will turn round an island or headland, and
(juite change or even reverse its course, and this perhaps in a
very short time, and with little or no variation in the velocity,
in despite of the action of the planet, shows how very small a
part of the cause its direct action is. 'J'he height of the tide,
therefore, in particular places has been made to depend on a
cause which produces directly scarcely any part of it ; and the
horizontal displacements and velocities, which ought chiefly
to be considered, have been entirely neglected. This has no
doubt been owing to the extreme difficulty of taking account
of them.

The difficulty experienced in putting the coefficient of
cos ((p— jS,) under a suitable form, owing to our not being able
to estimate with sufficient precision fche relative magnitudes
of the quantities which it contains, renders it very difficult to
say what alteration this theory will make in the height of the
tide as it depends on the declinations of the planets, and it is
possible that the coefficient may vary greatly in different
places.

It will be seen that in the coefficients of both cos2((p— /Sj)
and cos (f — /3,) this theory makes a considerable alteration as

On the Compounds of the Halogens 'with Phosphorus. 345

to the manner in which the variable quantities enter them.
And if we were to take account of tlie powers and products
of the displacements of the second order, a further change
would be protluced, and one which might be very sensible. I
may ))erhaps give the subject a brief consideration at some
future opportunity, if not prevented.

Gunthwaite Hall, near Barnsley, Yorkshire,
October 5, 1849.

XLIV. On the Compounds of the Halogens ivith Phosphorus.
% J. H. Gladstone, Ph.D.*

r\URING the course of my recent examination of the com-
-*-^ pounds of phosphorus and nitrogen, I had occasion to
prepare considerable quantities of pentachloride of phosphorus;
and some observations which I incidentally made upon that
substance, induced me to undertake a fuller investigation into
such combinations of phosphorus with the halogens.

It is well known that if chlorine gas be passed over phos-
phorus, they combine energetically, forniing in the first in-
stance a limpid liquid, which is a combination of three atoms
of chlorine with one of phosphorus. If the proper amounts
of bromine and phosphorus be brought into contact, a similar
terbromide is the result. If one part of phosphorus and
twelve parts of iodine be mixed, a red, easily fusible solid re-
sults, which appears to be an analogous compound. And
again, if a larger quantity of chlorine, or bromine, or iodine,
be employed, crystalline bodies are produced, which are com-
binations of five atoms of the halogen with one of phosphorus.
The same penta- compounds result when an additional quan-
tity of the halogen is added to the substance containing three
atoms. I have not succeeded in bringing about similar com-
binations between cyanogen and phosphorus: in fact, this
element may be distilled unchanged in an atmosphere of
cyanogen gas.

These compounds form a very distinctly-marked class of
bodies. They are neither acid nor basic ; and they are re-
solved by water into the hydracids of the halogens, that is,
hydrochloric, hydrobromic, or hydriodic acid, and phospho-
rous, or phosphoric acid, — according to the number of atoms of
the element replaced by oxygen. In these respects they differ
from the combinations of sulphur with phosphorus, which
have acid properties, are not readily decomposed by water,
and are in fact strictly analogous to the oxygen compounds,

* Communicated by the Author.

346 Dr. Gladstone on the Compounds of the

It is also well known, that if the combination between phos-
phorus and the halogen be made by means of a metallic salt
that yields up its electro-negative element readily, or in
other words, if phosphorus be distilled with the chloride, bro-
mide, or iodide of mercury, it is the ter-compound that results.
In this manner also Davy produced a ter-fluoride. Canedella*
states that if cyanide of mercury and phosphorus be heated
together, combination ensues, frequently with explosive vio-
lence, and a sublimate is formed resolvable by water into
phosphorous and hydrocyanic acids. On repeating his ex-
periment I did obtain a sort of explosion, and a minute quan-
tity of a substance which answered somewhat to the description
given. A subsequent attempt, however, was quite unsuc-
cessful. The uncertainty attending the preparation, together
with the high probability that poisonous exhalations would
arise from such cyanides when exposed to the air, rendered
me disinclined to pursue the investigation further.

In order to prepare one of these ter-compounds by means
of a metallic salt, it is not necessary that* the salt should be
capable of decomposition by heat alone. I have prepared ter-
chloride of phosphorus by making use of the chlorides of
iron and copper ; and doubdess other metallic chlorides might
be substituted. Chloride of lead, however, I found not to be
decomposed by phosphorus.

The comparative weakness with which the two additional
atoms of the pentachloride of phosphorus are held in combina-
tion, is evident from the ease with which compounds are ob-
tained, where these two atoms of chlorine are substituted by
sulphur and oxygen, as already made known by Serullas and
Wurtz; but the readiness with which the penta-corapounds
are reduced to the ter-compounds has never, I think, been
pointed out. If the chloride, bromide, or iodide of phos-
phorus, containing five atoms of the halogen, be heated in con-
tact with fresh phosphorus, chemical action is instituted, and
the whole is reduced to the compound containing three atoms.
With the bromide the application of extraneous heat is quite
unnecessary: with the iodide, the reduction will proceed even
to the formation of a compound containing a much smaller
amount of iodine, but of a totally different character to the
bodies now under consideration. Upon this may be founded
a good method for obtaining the terchloride and terbromide,
as their freedom from admixture with the higher combination
can then be depended upon : sufficient phosphorus must be
employed to reduce the whole, and the liquid may be distilled
of perfect purity. Similarly, it has been heretofore observed,
* Annul, der Pharm., xviii, 70.

Halogens mth Phosphorus. S^?

that the pentachloride of phosphorus is reduced to the ter-
chloride by the action of phosphuretted hydrogen ; and this
again is completely decomposed, if the current of gas be con-
tinued. If the yellow crystals of pentabromide be subjected
to the same treatment, a liquid compound is instantly pro-
duced, whilst acid fumes are evolved ; and the long-continued
action of the phosphuretted hydrogen gas causes the entire
disappearance of the liquid, yellow phosphorus being left in
its place. The reaction is evidently the same as in the case
of the chloride, and may be expressed by the two formulae, —

SPBr^-f PH3 = 'iPBr3+3HBr,
and

PBr3 + PH3=2P + 3HBr.

Although phosphuretted hydrogen is thus capable of re-
ducing these combinations of phosphorus with the halogens,
pure hydrogen gas has not the slightest effect upon the penta-
chloride of phosphorus even at the subliming point of that
substance; nor does it produce any alteration in the penta-
bromide,— at least not at the ordinary temperature. Heat
alone, however, will effect the reduction of this latter com-
pound, provided a stream of dry air be passed over it : the
experiment is conveniently made in a water-bath at 100°C.,
when bromine passes off, and the liquid terbromide re-
mains. The peculiar reddening of the pentabromide during
sublimation, first observed by Balard, is in all probability
owing to this cause. When the penta-compound fuses, it is
partially decomposed into terbromide of phosphorus and free
bromine, which colours the liquid red; the two rise in vapour
together, thus producing a red gas; and when they reach a
sufficiently cool portion of the vessel, recombine to form the
lemon-yellow crystals of the penta-compound. It is not in-
tended by this explanation to deny that pentabromide of phos-
phorus may be capable of volatilization without being decom-
posed. In a similar manner, the higher compound of iodine
and phosphorus may be reduced by the aid of heat alone.
The pentachloride, on the contrary, resists the decomposing
action of heat.

The relative force of affinity between phosphorus and the
three halogens to which my attention has been more espe-
cially directed, is in the order, — Chlorine, Bromine, Iodine.
Thus, teriodide of phosphorus is decomposed by both chlorine
and bromine; the terbromide by chlorine, but not by .iodine;
whilst the terchloride is not decomposed by either of the other
elements. The same is indicated by the fact that terbromide
of phosphorus distilled with chloride of mercury yields ter-»

3*8 Dr. Gladstone on the Compounds of the

chloride of phosphorus, and bromide of mercury, which re-
mains in the retort. None of these three ter-compounds is
directly acted upon by oxygen gas; the terchloride of phos-
phorus is unaffected by sulphur at any temperature; the ter-
bromide also appears to enter into no definite combination ;
yet, if the oxygen or sulphur be united with hydrogen, double
decomposition ensues. Water, as is well known, resolves
these ter-compounds into the hydracids and phosphorous acid:
hydrosulphuric acid, as observed by Serullas, resolves ter-
chloride of phosphorus into l)ydrochloric acid and tersulphide
of phosphorus: a similar reaction takes place with the ter-
bromide, which may be expressed by the formula —

PBr3+3HS=PS3 + 3HBr.

When we consider the action of these non-metallic elements,
and their hydracids, upon the penta-compounds, we are again
reminded of the comparative feebleness with which the two
additional atoms are combined. Pentachloride of phosphorus,
it is true, is unaffected by bromine, and the action of iodine
upon it did not appear to me well-defined ; but pentabromide
of phosphorus, carefully prepared so as to avoid excess of
bromine, when brought into contact with iodine at the ordi-
nary temperature, quickly ran down into a red liquid, and
terbromide was found in the vessel. Very little iodine is re-
quired to effect this reaction ; and since the compound IBr-
is known to be readily formed, the decomposition in all pro-
bability may be thus expressed : —

5PBr5 + 2l = 5PBr3 + 2lBr5.

The action of sulphur upon these penta-compounds is remark-
able. If it be mixed with the pentachloride of phosphorus,
and the whole fused together, combination ensues ; but this
is not a case of reduction ; and the new products — a liquid
and a crystalline body — require a more lengthy consideration
than can be given them in this paper. Again, if pentabro-
mide of phosphorus be mixed with sulphur, no action takes
place in the cold ; but upon gently raising the temperature,
combination is instituted; the odour of bromide of sulphur is
perceptible; and a liquid is produced, which appears to con-
sist, partially at least, of a compound that will be presently
described.

We have now to consider the manner in which these penta-
compounds of the halogens with phosphorus I'requently part
with the two additional atoms when treated with hydrogen
compounds. Hydriodic acid reduces the pentachloride of
phosphorus to the terchloride, a fact first remarked by Se-

Halogens with Phosphorus. 349

rullas* ; yet I did not find the same occur with the pentabro-
mide ; nor was the pentachloride itself affected by a stream
of hydrobromic acidf, even when heated. The proto-com-
pounds of oxygen and sulphur with hydrogen act somewhat
differently : the hydrogen enters into combination with the
two atoms of the halogen that are more easily removable, and
leaves the oxygen or sulphur in combination with the phos-
phorus compound. These substances in the chlorine series
are the oxychloride of phosphorus described by WurtzJ,
having the composition PCI3 Og, and the sulphochloride of
phosphorus discovered by Serullas§, bearing the formula
P CI3 Sg. In order to produce this oxygen compound, the
action of the water must be moderated, or a secondary trans-
formation into phosphoric and hydrochloric acids will take
place. This may be effected either by throwing the white
crystals of pentachloride of phosphorus into water, when they
are instantly converted into the liquid oxychloride, and imme-
diately afterwards drawing off the supernatant fluid ; or, with
greater ease, by exposing the solid chloride to the moisture
of the atmosphere until the conversion is complete, hydro-
chloric acid being constantly evolved. A compound strictly
analogous to this, may be obtained from the pentabromide of
phosphorus by either of the two processes. The latter is of
course preferable.

Oxyhromide of Phosphorus. — When pentabromide of phos-
phorus is entirely decomposed by a moist atmosphere, there
remains in the vessel a reddish liquid of a sticky consistency.
This must be gently heated to expel hydrobromic acid, of
which it contains a large quantity ; and then, upon distillation
at about 180° C, a heavy vapour passes over, condensing into
a colourless liquid of high specific gravity. It does not mix
with water, but is slowly resolved by it into phosphoric acid
and hydrobromic acid. It is soluble in oil of turpentine and
in aether, and is also dissolved by strong sulphuric acid, from
which it may be precipitated by water, unchanged, but soon
suffering, of course, a secondary decomposition. Nitric acid
destroys it violently with evolution of bromine. Bromine
added to it reproduces momentarily the yellow crystals of

* Ann. de Chim. et de Phys., xxxviii. 322.

\ Hydriodic or hydrobromic acid in a gaseous condition may be conve-
niently prepared by the action of iodine or bromine on hyposulphite of soda
moistened with a little water. The reaction will be evident from the equa-
tion—

NaO,S2 02+HO+Br=NaO,S03+S+HBr.

In the case of iodine it is necessary to apply heat.

X Ann. de Ch. et de Phys., 3rd ser. xx. 472. § Ibid. xlii. 25.

350 Dr. Gladstone on the Compounds of the

pentabromide; but the final result is a liquid, which, upon
the application of heat, evolves bromine, and apparently leaves
the original substance behind unaltered. Chlorine displaces
the bromine in this compound, red vapours being immediately
evolved when it is treated with that gas.

The analysis of this substance was effected by decomposing
it in water, and precipitating the hydrobromic and phos-
phoric acids, thus produced, in the usual manner. The re-
sults, as given below, fully confirmed the expectation that this
new liquid was the oxybromide of phosphorus, having the
composition P Br3 O^.

0*6245 grm. of substance yielded 1*227 grm. of bromide of
silver, and 0*1514' grm. of phosphoric acid.

O'Sll grm. of another preparation yielded 1*605 grm. of
bromide of silver.

Or, calculated to 100 parts, —

By calculation
By experiment. from P Bi-g O2.

Phosphorus . . 10*77 ... 11*29

Bromine . . . 82-50 83*11 83*06

Oxygen ... 5'65

The production of this oxybromide of phosphorus will be
expressed by the equation —

PBr5 + 2HO=PBr3 02 + 2HBr.

I have not succeeded in accurately determining the boiling-
point of the liquid under consideration. It appears to vary
between 1 70° C., and perhaps 30 degrees higher. Kopp finds
that the substitution of three atoms of chlorine by three atoms
of bromine in a compound, causes an elevation in its boiling-
point of 96° C. Thus, the terchloride of phosphorus boils at
78" C. ; the terbromide at 175°C. (Pierre), or 174° C, accord-
ing to my own observations. Now, as oxychloride of phos-
phorus boils at 110° C, this would give as the boiling-point
of oxybromide of phosphorus 206° C. ; but experiment cer-
tainly does not indicate it as so high.

I may liere remark that, in the decomposition of this oxy-
bromide by water, there is usually formed a small quantity of
a brown resinous-looking matter, not acted upon by water,
nor soluble either in potash or nitric acid. It has a very
characteristic odour. I have never obtained it in sufficient
quantity for thorough examination. This readily accounts
for the slight loss in the first analysis recorded above.

Sulpho-bromine Compound. — On passing a stream of hydro-
sulphuric acid over pentabromide of phosphorus, combination
instantly ensued ; the yellow crystals gave place to a colour-

Halogens mth Phosphorus. * 351

less or slightly red liquid, whilst hydrobromic acid was evolved:
no free bromine or bromide of sulphur was observed. When
the action was complete, the new product was first heated in
a water-bath to drive ofiP excess of hydrosulphuric acid, and
then distilled at about 200° C. A colourless dense liquid
passed over ; but analysis showed that it was not the sulpho-
bromide expected. The estimations, Nos. 1 and 2, recorded
below, were made from it. Fearing that a decomposition
might have taken place in the distillation of this substance, I
submitted some carefully prepared pentabromide of phos-
phorus to the action of dry hydrosulphuric acid, and examined
the resulting liquid itself. It was colourless, or slightly red,
of high specific gravity, and fumed in moist air, giving forth
a disgusting and deleterious odour. It was slowly decomposed
by water, sulphur being deposited, and hydrobromic and
phosphorous acids being dissolved : there was also in solution
a sulphide of phosphorus, which gave a brown precipitate with
a silver salt, but no hydrosulphuric acid. If alkali were added
to the water, decomposition took place much more rapidly.
It was soluble in aether, insoluble in cold sulphuric acid ; but
upon raising the temperature to about the boiling-point of the
substance, decomposition ensued, the sulphuric acid became
red, hydrobromic acid was evolved, and afterwards bromide
of sulphur. Strong nitric acid attacked it violently ; the phos-
phorus and sulphur being oxidized, the bromine dissipated.
When treated with bromine, it gave momentarily the yellow
crystals of pentabromide of phosphorus ; then gas was evolved,
and it again became liquid. It boiled at about 200° "C. with-
out alteration. The quantitative estimation of its elements
gave analysis No. 3, proving its identity with the liquid first
analysed.

As the hydrosulphuric acid employed in these experiments
was made li*om sulphide of iron, and was dried by passing
through sulphuric acid, I suspected that free hydrogen might
possibly have interfered with the reaction, although it does
not affect pentabromide of phosphorus itself when alone. The
experiment was therefore repeated with hydrosulphuric acid
prepared from sulphide of antimony, and dried by means of
chloride of calcium. When the resulting colourless liquid was
thoroughly saturated with the gas, it was found to be similar
to that previously obtained. It afforded analysis No. 4.

The analyses numbered 1, 3, and 4 were performed by
oxidizing the liquid by means of nitric acid. The second ana-
lysis was obtained by allowing the liquid to remain under
water until entirely decomposed, precipitating the bromine by
nitrate of silver, heating the precipitate with nitric acid in order

352 Dr. Gladstone on the Compounds of the

to destroy the brown salt produced at the same time, estima-
ting the sulphuric acid thus formed in the usual manner, and
adding the amount of sulphur it contained to that left undis-
solved in the aqueous solution.

I. 0*200 grm. of the liquid yielded 0*075 grm. of sulphate
of baryta, and 00702 grm. of phosphoric acid.

II. 0'373 grm. yielded 0*07255 grm. of bromide of silver,
0*0125 grm. of sulphur, and 0'04-5 grm. of sulphate of baryta.

III. 0*444'5 grm. yielded 0*173 grm. of sulphate of baryta,
and 01 36 grm. of phosphoric acid.

IV. 0*2965 grm. yielded 0*124' grm. of sulphate of baryta,
and 0*0848 grm. of phosphoric acid.

Or, reckoned to 100 parts, —

I. II. III. IV.

Phosphorus . . 15'6 ... 13*6 12*8

Bromine 81 '6

Sulphur ... 5*2 5*0 5*4 5*7

This does not accord well with any simple formula. If we
suppose it to be a chemical combination of three atoms of ter-
bromide with one atom of tersulphide of phosphorus, i. e. a
sulpho-phosphite of the bromide of phosphorus, we obtain
numbers which are similar.

Calculated from SPBrs + PS.,-

Phosphorus 14*5

Bromine 80*1

Sulphur 5*4

1000

It is possibly, however, amixtureof two distinct substances
having nearly the same boiling-point.

It does not appear that similar compounds belonging to the
iodine series exist. Pentiodide of phosphorus is rapidly de-
composed by the moisture of the atmosphere, but it did not
furnish an oxy iodide. Hydrosulphuric acid has no action
on the pentiodide of phosphorus, either at the ordinary tem-
perature, or when fused by the heat of a water-bath. ;jii

It is remarkable to observe the increased stability which
these two atoms of oxygen, or sulphur, give to the compound
of phosphorus with three atoms of the halogen. Whereas
hydrosulphuric acid is capable of completely decomposing
both the terchloride and terbroniide of phosphorus, it is in-
capable of removing the three atoms of chlorine from the sul-
phochloride of phosphorus, and also the remaining bromine
from the compound of bromine, sulphur, and phosphorus just
described. Again, whilst metals immersed in terchloride of
phosphorus, or terbromide, are attacked by them, they remain

Halogens with Phdsphoi'iisP '^ 353

unaltered in oxychloride, or oxybromide of phosphorus, or the
sulpho-bromine compound. Even potassium, which instantly
inflames with violence when brought into contact with ter-
chloride of phosphorus, will remain quite unaffected in the
oxychloride, and combination is not determined even by boil-
ing the liquid. It is true, the less easily oxidized metals, such
as silver or platinum, are not attacked by terchloride of phos-
phorus at any temperature ; but even platinum is acted upon
by the pentachloride with the assistance of heat, the com-
pound being entirely decomposed. And lastly, whereas the
penta-compounds of the halogens with phosphorus may be
reduced by means of additional phosphorus, no such reduction
of the oxychloride takes place. This substance is also un-
affected by iodine, bromine, or chlorine.

There appears no reason why a compound of phosphorus
might not be formed, in which two of the halogens should be
associated ; but all my attempts to procure such a body have
proved unavailing. Many of the experiments given above
were undertaken with that view. It occurred to me also, that
since chlorine decomposes both the pentabromide and iodide
of phosphorus, hydrochloric acid might possibly effect a par-
tial double decomposition ; but I found it had no action upon
either. If chloride of mercury and pentiodide of phosphorus
be heated together, double decomposition does ensue ; but it
extends to the three atoms more intimately connected with
the phosphorus, and the two additional atoms of iodine are
set free : thus —

Pl5+3HgCl=PCl3 + 3HgI + 2l.

Since a halogen, bromine for instance, combines directly
with the ter-compound of the same halogen with phosphorus,
it appeared not improbable that it might combine readily with
another ter-compound. But, when bromine is poured upon
the terchloride of phosphorus, it merely sinks to the bottom,
and the two liquids cannot be made to mix. If, however, a
little iodine be added, a junction is instantly effected, attended
with great evolution of heat : when the temperature falls, a
red crystalline mass separates, resembling pentabromide of
phosphorus when prepared with excess of bromine. In order
to prove whether it was really this substance, or some new
compound, it was necessary to separate it, if possible, from
the accompanying liquid. This could not be effected by di-
stillation, and the action of solvents was destructive : purely
mechanical means therefore had to be resorted to. A com-
pound of bromine and iodine was prepared, and terchloride of
phosphorus was allowed to fall into it, drop by drop, as long

Fhih Mag. S. 3. Vol. 35. No. 237. Nov. 1849. 2 A

354) Dr. Gladstone on the Compounds of the

as the crystals appeared to increase in quantity ; the superna-
tant liquid was then poured off, and the crystals were allowed
to drain, without free exposure to the atmosphere, and were
afterwards transferred to a porous tile also protected from
moist air. When they appeared as dry as they were likely to
become, they were analysed through decomposition by water,
and precipitation of the hydracids by nitrate of silver.

0'431 grm. of the red crystals yielded 0*910 grm. of bro-
mide of silver, and O'llS grm. of chloride of silver.

This indicates 88*6 per cent, of bromine, and 6*4 per cent,
of chlorine. Evidently, therefore, the crystalline body was no
combination of both halogens with phosphorus, but merely
pentabromide of phosphorus contaminated with a little of some
chlorinated compound. The pentabromide requires 92*45
per cent, of bromine, and 7*55 per cent, of phosphorus. The
reaction that takes place is in all probability very simple, —

PCl3 + IBr5 = PBr5+ICl3.

If iodine be added to the terchloride of phosphorus, a red
solution is immediately obtained. If this be subjected to a
temperature a little below 100° C, a red liquid distils over.
Quantitative analysis showed that this was merely a solution
of iodine in the terchloride ; that element having passed over,
in considerable quantity, with the vapour of the compound, at
a temperature far below its own subliming point. In the same
manner, if iodine be added to the terbromide of phosphorus,
a red liquid is obtained, but without chemical combination.

Nor does it appear that direct combination will take place
between phosphorus and the compounds of the halogens
themselves. When the liquid chloride of iodine is added to
phosphorus, violent combination ensues ; iodine is liberated ;
and, even if a double compound be at all formed (which I
doubt), it is destroyed by heat, and resolved into chloride of
phosphorus and iodine. Again, if phosphorus be brought
into contact with the orange-yellow crystals of terchloride of
iodine, a blue colour is instantly developed, as though from
the liberation of iodine, and a result is obtained similar to
that in the former experiment.

Before quitting the compounds of bromine and phosphorus,
I must mention a crystalline body, which I frequently ob-
tained during my investigation of them, but wliich, from not
understanding the conditions of its formation, I have never
procured in any considerable quantity ; and, in the attempt
to purify it, I have almost uniformly destroyed the little I did
possess. In distilling terbromide, or oxybromide of phos-
phorus, there remained in the retort, on several occasions, a

Halogens mth Phosphorus. 355

small amount of these crystals; and they were observed to
form on the yellow pentabromide of phosphorus, when imper-
fectly secured from the action of the atmosphere, but before
complete conversion into oxybromide. They are perfectly
transparent and colourless, with sharply-defined edges; theyare
decomposed by water : by the moderated heat of a spirit- lamp
they fuse, and immediately sublime. But this fusion is apt to
produce an alteration in them : instead of re-crystallizing on
cooling, a permanent liquid is sometimes found, having the
characters of oxybromide of phosphorus. The only analysis
I obtained was made with a very small quantity.

0*1125 grm. yielded 0*2255 grm. of bromide of silver, and
0*048 of phosphate of magnesia.

Or, reckoned to 100 parts, —

Phosphorus 12*0

Bromine . . . . . . 84*2

Oxygen, or loss ... 3*8

1000
Is this crystalline body isomeric with liquid oxybromide of
phosphorus? or is it some compound containing less oxygen?
May it not also possibly account for the variations in the boil-
ing-point of the oxybromide?

We are unacquainted, I believe, with any method by which
the iodides of phosphorus can be purified from excess of iodine.
Thus they have never been analysed. It is on this account,
also, that my researches have not been carried so far with the
iodine as with the bromine compounds ; nor can I feel perfect
confidence in all the results at which I have arrived in refer-
ence to them.

Thus have we seen the manner in which the halogens
combine with phosphorus, forming ter- and penta- com-
pounds ; and also some methods by which the compounds
containing five atoms of the halogen may be reduced to those
containing three. The comparative feebleness of the combi-
nation of the two additional atoms has been rendered still more
evident by the action of certain elementary bodies, and of
the compounds of these elements with hydrogen. Among the
products of these reactions are an oxybromide of phosphorus,
and a sulphur compound of less simple formula. It has also
been remarked how the substitution of oxygen, or sulphur,
for two of the elements of halogen in a penta-compound, in-
creases the force with which the remaining three are combined.
And lastly, the great indisposition of any two halogens to enter
together into a phosphorus compound has likewise been ob-
served.

2 A2

[ S56 ]

XLV. On Shooting Stars.
By Sir J. W. Lubbock, Bart,, RR.S.^

SOME time since, in a paper in the Philosophical Magazine,
I ventured to suggest that the disappearance of shooting
stars might be occasioned by their passing into the earth's
shadow, or in other words, by being eclipsed. Lately, in
looking over the Astronomische Nachrichten, I found in
No. 614-, in a paper entitled " Ueber eine Langenbestimmung
aus den August-Sternschuppen," 184-7, by M. Weyer, three
observations of shooting stars, which might, supposing their
distance from the earth's surface as given in that paper suffi-
ciently accurate, serve to test in those instances the truth of
my hypothesis. Accordingly I requested Mr. Farley to cal-
culate the distance of the bodies, and the following tables ex-
hibit the results obtained, and the data, as furnished by the
tables in the Ast. Nach. They do not appear to be favour-
able to the hypothesis above referred to. The notation is as
follows, conformably to that of my preceding paper : —

R = earth's semidiameter = 3958 miles.

a = azimuth of shooting star — azimuth of sun; reckoned
from the south meridian westward,

^ = apparent zenith distance of shooting star.

p = distance of shooting star from the spectator.

0 = depression of sun's centre, so that 90° + 9 = sun's ze-
nith distance.

1847.

Mean time

at
Hamburg.

Place of
disap-
pearance.

Mean time

at Pa-
penburg.

Place of
dis-
appearance.

Distance from the earth's 1
surface in

German miles.

English miles.

Aug. 10..

h m 8
10 54 2

10 58 43

11 40 25

Herculis
Lyrse ...
Lyrse ...

h m 8
10 43 53

10 48 34

11 30 16

« Pegasi ...
a, Androm.
/3 Arietis...

12
18
10

55

83
46

In order to estimate the effect which an error in the as-
sumed place of disappearance would have upon g, it has been
calculated upon three different hypotheses: —

1. Supposing the shooting star to have disappeared at Pa-
penburg, having the same R.A. and Dec. as the star indi-
cated in the Ast. Nach.

2. Supposing the place so assumed to be in error 3° or
12"^ in R.A., and the Dec. to be correct.

3. Supposing the place assumed to be in error 3° in Dec.
and the R.A. to be correct,

* Communicated by the Author.

Mr. J. Glaisher's Remarks on the Weather.

357

The last column contains the value of q as obtained from
the distance from the earth's surface given in the Ast. Nach.
For the purpose of comparison, it will be seen that much
greater errors than those I have assumed in the place of the
shooting star's disappearance would be required to conciliate
the two results.

We found for the instant of disappearance and for Papen-
burg,—

Assumed place of
disappearance.

i-

Azimuth.

L

©'3

Azimuth.

OS.

in Knglish

R.A.

Dec.

miles.

1....

h m
22 57

o /

+ 14 23

52 9

300 44

19 9

159 16

0 /

141 28

555

84

2....

23 9

+ 14 23

53 43

297 40

19 9

159 16

138 24

591

84

3....

22 57

+ 17 23

49 38

298 36

19 9

159 16

139 20

500

84

1....

0 1

+28 15

49 32

275 44

19 21

160 12

115 32

422

124

2....

0 13

+28 15

51 20

273 52

19 21

160 12

113 40

436

124

3....

0 1

+31 15

47 22

272 57

19 21

160 12

112 45

393

124

1....

1 46

+20 4

65 9

269 16

20 55

171 8

98 8

633

170

2....

1 58

+20 4

66 57

266 53

20 55

171 8

95 45

649

170

3....

1 46

+23 4

62 21

267 6

20 55

171 8

95 58

579

170

It seems very desirable to procure other observations of
this kind made by two or more persons, having their time
sufficiently accurate to be able to identify the meteor, and by
each noting as accurately as possible the place of disappear-
ance, so that they may be enabled through the parallax of the
body to determine its distance from the earth. I do not see
in what manner isolated observations by one person can in
the present state of the subject tend to elucidate this interest-
ing question. The paper in the A&t. Nach,, to which I have
referred, affords ample evidence that such combined efforts
would in all probability be attended with success. The de-
termination of the distance of the body by means of its paral-
lax is of course independent of any hypothesis as to its na-
ture, and may therefore serve as a guide in any reasoning
upon that point.

XLVI. Remarks on the Weather during the Quarter ending
September 30, 1849. By James Glaisher, Esq., F.R.S.,
F.R.A.S., and of the Royal Observatory, Greenwich^,

A MORE than ordinary interest is attached to the meteor-
-**■ ology of the present year, and in particular to that part
of the year just passed, owing to the presence of cholera as an
• Communicated by the Author.

358 Mr. J. Glaisher's Remarks on the Weather

epidemic complaint. This disease has been fatal during the
last quarter to a great number of persons. The number of
deaths in London and in its vicinity, according to the weekly
Reports of the Registrar-General, exceeded the average num-
ber of deaths in July by 2515, in August by 4464, and in
September by 4322, out of a population of 2,206,076 ; a mor-
tality unprecedentedly great.

I have no means of judging of the amount of illness, but it
must have been great.

If epidemics be due to atmospheric causes acting upon local
circumstances, it is to the successful cultivation of medical
meteorology that we can hope to contend with them with
success.

Those causes of sickness which depend upon temperature,
humidity, pressure or movement of the air, admit of measure-
ment; and it must be considered as a most valuable circum-
stance, that nearly forty educated gentlemen — known and
trustworthy observers, with good instruments — were daily
engaged, long before the epidemic came, in collecting this in-
formation. Without this organization our knowledge of the
meteorological particulars of the period would have been as
deficient as it is of the year 1832, when the cholera was before
prevalent.

The results thus collected may now be compared with those
of former years, as far as the previous years will furnish the
materials of comparison, with those for instance when epi-
demics prevailed, as in 1832, and with those of non-epidemic
years, as in 1842, a year which was unusually free from epi-
demic diseases. Those gentlemen who may wish to investigate
the connexion which may have existed between the sickness
and mortality of the seasons, with their meteorological parti-
culars, will find the monthly values of the subjects of meteor-
ological research in the Quarterly Reports of the Registrar-
General, with the names of the gentlemen who have furnished
the observations; and most of those gentlemen would be
happy to furnish detailed copies from their registers for short
periods to any gentleman who would use them in connexion
with sickness or mortality.

The quarterly meteorological returns for the past quarter,
furnished to the Registrar-General and myself^ have been
received from thirty-eight different places, whose returns have
been found on examination to be good. These have all been
examined and reduced by myself.

At Greenwich the mean daily temperatures of the air from
July 1 to July 17 were above their average values; the mean
excess was 3°*2. From July 18 to August 5 they were below

during the Quarter ending September 30, 1849. 359

their average values ; the mean deficiency was 2°*2. From
August 6 to August 12 the temperature was high; its mean
daily excess was e'^'O. From August 13 to August 19 the
mean deficiency was 1°'9. From August 20 to September 15
the temperature was high ; its mean excess was 4° ; and this
period was distinguished by a thick and stagnant atmosphere,
and the air was for the most part very close and oppressive.
The temperature was 3°*3 below its average from September 1 1
to September 21 ; and it was 5°' 5 in excess from September 22
to the end of the quarter. The summer has been warm and
dry, without great heat. Thunder-storms have been very
frequent during the quarter. The air has been for the most
part unusually dry. The amount of rain has been less than
usual in latitudes south of 53°, and north of this parallel it
has been greater. The magnets have been seldom disturbed
during the quarter ; and the amount of electricity, though less
than usual, seems to have been so in consequence of the less
amount of humidity of the air.

The weather has been much finer in the southern than in
the northern parts of the country.

The mean temperature of the three months ending August,
constituting the three summer months, was 61°'0; and that
of the average of seventy summers is 60°*0.

The several subjects of research in the past quarter are as
follows : —

The mean temperature of the air"^ for the month of July was
62°-l, which is 4°-3, l°-9, l°-2, 0°-7, 2°'3 and 0°-6 afiot;^ those of
the years 1841, 1842, 1843, 1844, 1845 and 1848 respectively;
and is 2°'4 and 3°'3 below those of the years 1846 and 1847
respectively. The temperature of this month exceeded its
average from seventy years by 0°*7.

For the month of August was 62°- 9, which is 2°-4, 0°-8,
5°-2, 5°'6i 0°-8 and 4°-4 above those of the years 1841, 1843,
1844, 1845, 1847 and 1848 respectively; and is 2°-5 and 0°-3
below those of the years 1842 and 1846 respectively. The
temperature of this month exceeded its average from seventy
years by 2°*1.

For the month of September was 58°'8, which is 0°*7, 2°'4,
1°'9, 5°'2, 4°"5 and 3°'0 above those of the same month in the
years 1841, 1842, 1844, 1845, 1847 and 1848 respectively;
and is 0°-7 and l°-3 below that in 1843 and 1846. The
temperature of this month exceeded that of the same month
on an average of seventy years by 2°*1.

* For the monthly, quarterly and yearly mean temperature of the air
from 1786 to 1843, see my paper in the Philosophical Transactions, partii.
1 849 ; and for the mean monthly values of several meteorological elements,
see my paper on Meteorology in the Illustrated London Almanac for 1850,

360 Mr. J. Glaisher's Remarks on the Weather

The mean temperature of evaporation at Greenwich —

For the month of July was 56'*2; for August was 57^*3;
and for September was 54-°-6. These values are l°-3 less,
0°'4 less and 0°vl greater, respectively, than the averages of the
same months in the preceding eight years. The mean value
for the quarter was 56°*0. which is 0°'5 below the average of
the corresponding quarters of the eight preceding years.

The mean temperature of the dew-point at Greenwich —

For the months of July, August and September, were 51°*1,
53''-0 and 5l°-0 respectively. These values are 3°-6, 2°'4 and
l°"6 below the average of the same months in the preceding
eight years. The mean value for the quarter was 51°*75 being
of less value than in the same quarter of each of the eight pre-
ceding years, and less than their average by 2°'5. This implies
that less water has been mixed with the air during this period
than in any of the corresponding quarters for eight years.

The mean elastic force of vapour at Greenwich for the quarter
balanced a column of mercury O'^OO inch in height. Its
average value for the corresponding quarter of the eight pre-
ceding years was 0*433 inch. The difference implies great
dryness of the air.

The mean weight of vapour in a cubic foot of air for the
quarter was ^'S grains. The average from the eight preceding
years was 4*9 grains.

The mean additional weight of water required to saturate a
cubic foot of air was 1'6 grain. This value, from the eight
preceding years, was 1*1 grain.

The mean degree of humidity in July was 0'711, in August
was 0-772, and in September was 0*772. The averages for
the eight preceding years were 0*798, 0*837, and 0*858 re-
spectively.

The mean reading of the barometer at Greenwich in July was
29*789 inches, in August was 29-841, and in September was
29*767. These values are respectively O'Oll less^ 0*060
greater, and 0*048 less than the averages of the same months
for the preceding eight years.

The reading of the barometer was 30*03 inches at the begin-
ning of July. It decreased to 29*56 on the evening of the
4th, when it began to increase, and passed the point 30 inches
during the afternoon hours of the 8th, and was 30*25 on the
11th at 9 A.M. This was the highest reading in the month.
The reading decreased below 30 inches on the 15th, and to
29*40 by the morning of the 20th ; it then increased to 29*94
by noon on the 23rd; it then decreased to 29*31 on the 25th,
and this was the lowest reading in the month ; it then increased
to 29*80 by the evening of the 28th ; then decreased to 29*52
at 3 P.M. on the 30th ; and after this increased to 29*80 at

during the Quarter ending September 30, 1849. 361

the end of the month. The range of readings during the
month was 0*94 inch.

In August the reading increased to 30*02 inches on the
morning of the 2nd at 9 a.m. ; decreased to 29-78 on the 5th
at 10 A.M. ; increased to 29*95 on the 7th at 9 a.m. ; decreased
to 29*56 bv the 9th at 9 p.m. ; increased to 29*95 on the 7th at
9 a.m.; decreased to 29*56 by the 9th at 9 p.m.; increased to
29*79 on the 1 1th at 9 a.m. ; decreased to 29*46 by the 13th at
3 P.M.; increased to 29*74 by 3 p.m. on the 15th; decreased
to 29*54 on the 16th at 3 p.m.; it then increased and passed
the point 30 inches about midnight on the 18th, and was 30*22
on the 21st; at which reading it continued almost all the day,
and then decreased, slowly passing below 30 inches after noon
on the 25th, to 29*69 on the 30th at 9 p.m., and then in-
creased to 29*74 by the 31st, The range of readings in the
month was 0*66 inch.

The reading decreased on September 1st to 29*50 inches at
9 P.M. ; then increased slowly till the 7th at midnight, when
it was 30*05 ; the decrease on the 8th was slow ; it was rapid
on the 9th and 10th; and the reading on the 11th was 29
inches nearly all the day ; on the 1 2th at noon the reading
was 28*88, being the lowest in the quarter ; after this time the
reading increased, and passed the point 30 inches before noon
on the 14th; and continued to increase till the 19th at noon,
when it was 30*36, being the highest in the quarter; after
this time it decreased, and passed below 30 inches before noon
on the 22nd, and continued to decrease till the 27th at 3 p.m.,
when it was 29*61 ; it then decreased slightly to 29*73 of the
morning of the 28th ; and then decreased to 29*08 by the end
of the month. The range in the month was 1*48 inch, being
greater than usual.

The average weight of a cubic foot of air, under the average
temperature, humidity and pressure, was 524*6 grains. The
average for the preceding eight years was 525*8 grains.

The rain fallen at Greenwich in July was 2*9 inches, in
August was 0*45, and in September was 3*3. The amount
for the quarter was Q>'Q. The average for this quarter in the
preceding eight years was 7*2.

The fall of rain in August was less than has fallen in August
since the year 1819. The average fall of rain at Greenwich,
from thirty-three years' observations, in July is 2*5, in August
2*4, and in September 2*4 inches. The fall was less than its
average at places south of latitude 53°, exclusive of Cornwall
and Devonshire; it was about its average fall between 53°
and 54° of latitude ; and north of 54° the fall was greater
than usual.

362 Mr. J. Glaisher's Remarlcs on the Weather

The excess of rain in the quarter in the counties of Cornwall
and Devonshire is owing to two remarkable falls which oc-
curred in Cornwall on September 22 and on September 26.
The observer at Helston mentions the falls on the nights of
those days as very remarkable. The observer at Falmouth
says, " a greater quantity of rain fell on the nights of the 22nd
and 26th of September than I have measured in the same
time for tv/elve years, viz. 1*925 and 1*964 inches respectively."
The observer at Truro says, " the quantity of rain for Septem-
ber is most extraordinary, amounting to 9*25 inches, particu-
larly the amount which fell on the 22nd, viz. 4*24' inches.
On the 26th a large quantity also fell, viz. 3*00 inches. The
total for the month exceeded that registered in any previous
month during the period of our observations (eleven years),
except in one instance, which, in the same month of Septem-
ber, slightly exceeds the present amount. The largest fall in
any one day previously noted was 2*10 inches (in December
1848); so that the quantity on the 22nd of September is
double that on any former occasion, and is rendered more re-
markable by being followed in four days by another far ex-
ceeding all except itself." These remarkable falls seem 'to
have been confined almost entirely to the county of Cornwall.

The directions of the wind at Greenwich were S.W. and
N.W. till July 8; was N.E. from the 10th to the 16th; and
it was mostly S.W. from the 17th to the end of the month.
From August 2 to 6 was N.W. and N.E. ; it was S.W. from
the 8th to the 17th; and was chiefly N.W. till the end of
August. It was mostly N. from September 1 to the 8th ;
S.W. from the 10th to the 16th; and N. and N.E. after this
time. From the observations of the direction of the wind
which have been taken daily at most of the principal railway
stations, and published in the " Daily News" on the following
day during the whole of the past quarter, it appears that the
general direction was the same all over the country when the
air has been in quick motion ; but that at other times its
direction has been variable, and very frequently in a calm
state at places whose elevation is inconsiderable.

The daily horizontal movement of the air in July was 120
miles; from August 1 to Uth was 50 miles; from August 12
to 16th was 170 miles; and from August 17 to the end of the
quarter was about SB miles, except on September 11 and 12th,
when it amounted to 190 miles daily. The average daily
horizontal movement of the air during the quarter is about
120 miles. Therefore during the months of August and
September the movement of the ^ir was about one-half the
usual amount.

during the Quarter ending September SO, 1849. 363

This remark applies to the place at which Osier's anemo-
meter is placed at Greenwich, viz. at an elevation of upwards
of 200 feet above the level of the sea, and near the northern
extremity of the table-land forming Blackheath. At places at
a less elevation, the movement of the air was very much less
than the above ; on many days, when a strong breeze was
blowing on the top of the observatory and over Blackheath,
there was not the slightest motion in the air near the banks of
the Thames; and this remarkable calm continued for some
days together, particularly from August 19 to the 24'th, on the
29th, from September 1 to the 10th, and after September 15.
On September 11 and 12 the whole mass of air at all places
was in motion, and the first time for nearly three weeks, the
hills at Hampstead and Highgate were seen distinctly from
Greenwich.

From the published observations of the strength of the wind
daily at all parts of the country, it would seem that the air
has been for days together in a stagnant state at all places
whose elevation above the sea is small.

The readings of the thermometer on grass in July were
below 40° on four nights; the lowest was 32°'8 ; between 40°
and 50° on twenty nights, and above 50° on seven nights. In
August the readings were below 40° on five nights ; the low-
est reading was 34°'5 ; between 40° and 50° on ten nights, and
between 50° and 60° on twelve nights. In September the
readings were below 40° on six nights; between 80° and 40°
on twelve nights, and about 50° on ten nights.

At Cardington the lowest reading on grass in July was
31°-8, in August was 32% and in September was 27°. The
mean of all the lowest readings was 45°*5 in July, 47°'t) in
August, and was 44°* 1 in September, as observed by Samuel
Charles Whitbread, Esq.

There were three exhibitions of the aurora borealis. The
first was seen on August 18 at Whitehaven ; the second was
seen at Latimer on September 3 at 8 p.m., when a rose-
coloured auroral arch was seen extending from south-west to
north-east across the zenith; and on Sept. 16 an aurora was
seen at Stony hurst.

Thunder-storms occurred on July 18 at Nottingham and
Leicester; on July 19 at Camberwell, Saffron Walden, Uck-
field and Greenwich ; on July 20 at Nottingham, Camberwell,
Saffron Walden, Leicester, Uckfield and Greenwich ; on
July 23 at Hartwell Rectory, Stone and Leicester; on July
24 at Camberwell ; on July 25 at Hartwell Rectory, Stone
and Camberwell; on July 26 at Camberwell, Leicester and
Greenwich; on July 29 at Nottingham and Leicester; on

364 Mr. J. Glaisher's Remarks on the Weather

August 1, 2 and 3, at Nottingham; on August 4? and 6 at
Helston ; on August 7 at Helston and Leicester ; on August
8 at Hartwell Rectory, Stone, and severe at Uckfield ; on
August 9 at Nottingham, Cardington, Liverpool and Lei-
cester : that at Nottingham is described as being violent. On
August 10 at Liverpool and Leicester ; on August 11 at Car-
dington, Hartwell Rectory, Stone and Uckfield ; on August
12 at Nottingham, Saffron Walden and Leicester; on Au-
gust 13 at Saffron Walden; on August 17 at Leicester and
Uckfield ; on August 30 at Nottingham ; on September 1
at Stone, Uckfield very severe, and Leicester ; on Sep-
tember 2 at Hartwell Rectory, Uckfield and Saffron Wal-
den : at this place the storm was very violent. On Septem-
ber 3 at Stone, Uckfield and Leicester ; and at Uckfield on
September 4 and 1 0.

Lightning was seen but thunder was not heard on July 19
and 20 at Saffron Walden ; on July 20 and 23 at Hartwell
Rectory and Stone ; on August 4 and 6 at Helston ; on Au-
gust 7 at Helston, Uckfield and Greenwich ; on August 8 at
Hartwell Rectory and Stone ; on August 9 at Cardington,
Liverpool and Stonyhurst; on August 10 at Liverpool; on
August 11 at Cardington, Hartwell Rectory, Stone, South-
ampton and Greenwich; on August 12 at Uckfield, South-
ampton and Saffron Walden ; on August 13 at Saffron Wal-
den ; on August 17 at Cardington; on August 18 at Car-
dington and Greenwich; on August 19 at Cardington; on
August 20 at Greenwich ; and on August 24 at Uckfield.

Thunder was heard but lightning was not seen on July 18
at Cardington and Holkham; on July 19 at Helston, Car-
dington, Hartwell and Stone ; on July 20 at Hartwell Rec-
tory and Stone; on July 22 at Helston; on July 23 at Hel-
ston, Cardington and Holkham; on July 25 very heavy
thunder was heard at Latimer; on July 26 at Cardington,
Hartwell, Stone, Southampton and Nottingliam ; on July 27
at Latimer; on July 31 at Cardington and Newcastle; on
August 8 at Holkham, Norwich and Newcastle ; on August 9
at Holkham, Latimer, Newcastle and Stonyhurst ; on August
10 at Newcastle; on August 11 at Latimer and Newcastle;
on August 12 at Holkham; on August 13 at Cardington,
Hartwell and Stone; on September 1 at Holkham, Hartwell
Rectory, Latimer and Southampton ; on September 2 at
Helston and Latimer; on September 3 at Holkham and
Hartwell ; on September 5 at Holkham and Wakefield; on
September 6 at Wakefield ; on September 10 at Wakefield
and Liverpool ; on September 20 at Helston ; on September
28 at Newcastle ; and on September 30 at Nottingham.

during the Quarter ending September 30, 1 849. 365

Hail fell on August 8 at Uckfield : the observer mentions
that the hailstones were as large as beans. Hail also fell on
August 12 at Saffron Walden.

Solar halos were seen at the following places : — On July 1
at Maidenstone Hill, Stone and Nottingham ; on July 2 at
Stone; on July 3, 19 and 21 at Maidenstone Hill; on July
25 and August 1 at Stone ; on August 9 at Hartwell and
Stone ; on September 1 at Maidenstone Hill ; on September
22 at Stone ; and on September 26 and 28 at Maidenstone
Hill.

Lunar halos were seen at Cardington on July 5, and at
Maidenstone Hill on September 2 and 28.

I have been favoured with the following agricultural reports.

At Guernsey, by Dr. Hoskins, F.R.S.

The weather during July was uniformly fine ; the quantity
of ruin rather above the average, distributed in equable showers
from the 18th to the end of the month. There was less
thunder and lightning than usual.

The crops without exception luxuriant. The mean tem-
perature of August was high, which, added to rain much be-
low the usual average, enabled the farmers to secure the har-
vest speedily and profitably. The earlier half of September
was warm and dry, the latter wet and windy. Potatoes small,
but good and abundant ; wall-fruit scanty, but figs in large
quantities, and thoroughly ripened. Cider apples scanty.

About the beginning of August cholera appeared in ill-
drained districts as an epidemic ; it spread erratically in
almost every part of the town and suburbs, and afterwards
appeared in isolated country houses, in which no morbific
cause could be traced. It declined towards the end of Sep-
tember.

Small-pox was also very general during this and the previous
quarter, as well in the country-places as in town. Vaccination
had been much neglected, owing to indifference and prejudice
on the part of the lower orders.

At Uckfield, by C. L. Prince, Esq., Surgeon.

The weather during the months of July, August and Sep-
tember, has been very fine, warm, dry, and remarkably
healthy, the mortality having been lower during this quarter
than in the corresponding quarter for several years past. The
temperature has been upon the whole very equable, and with-
out that excessive heat which usually characterizes a warm and
dry summer in the southern counties. The crops of hay and
of every species of grain has been abundant, very good in
quality, and secured in excellent condition. The hop plant
has been much diseased, and the crop far below the average.

360 - Mr. J. Glafsher's 'Remarlcs on the Weather

The failure of tliis crop is a great loss to the poor in this di-
strict; as from their earnings in hop-picking they are gene-
rally enabled to buy a certain amount of clothing, as well as
sundry other necessaries for the winter. The potatoe haulm
has been diseased in some situations, but I do not find that
the tuber has been in any way injured. The crop of apples
is good, and above the average ; but that of the pear, plum,
and wall-fruit generally, is almost entirely deficient, the blos-
som and trees having been much injured by the heavy snow
which fell in April.

At Stonyhurst, by the Rev. Alfred Weld, F.R.A.S.

Potatoes were first got up about June 30; it was then found
that about I lb. out of 20 lbs. was diseased : still there were
no signs of decay in the leaves, which looked strong and
healthy. About August 20 the tops of the potatoes seemed
struck by a general blight, which spread with such rapidity
that in two or three days from that period the fields were
quite black. The roots suffered at the same time in a greater
or less degree ; frequently the proportion of decayed to sound
potatoes was as two to one. Potatoes planted on damp soil
always suffered most, while others planted in sheltered spots
escaped with comparative immunity. It was found that in
one case, where clay and black bog soil existed in the same
field, potatoes planted on the former suffered severely, while
those on the latter remained untouched. The smell of the
decaying tops was offensive, and so strong as to be perceptible
at a considerable distance. After July 15 the weather became
very unfavourable for hay, and a great deal remained out until
August. The crop was far below the average. A distemper
broke out amongst horses about the middle of July, and was
followed by another which attacked the cattle ; both were in
some instances fatal. Reaping of wheat began August 25th ;
of oats, August 31st. The crops were far above the average,
and generally well-housed. The average length of oat-straw
grown on a field of six acres, which had not been ploughed
before for more than twenty years, was six feet, whilst in some
places it was above seven feet. The grain was with few ex-
ceptions all housed by the end of September.

For the West Riding of Yorkshire, by Charles Charnock,
Esq., of Leeds.

The past quarter has consisted of one wet and of two dry
months. The growth of turnips and potatoes were retarded
during the dry months, and progressed rapidly during that
which was wet. The harvest was very protracted on the
early soils, but secured in very good condition. On late soils
corn is still exposed to the weather. On the 2nd of October

during the Qiiarter ending September ^, 184-9. 367

I saw corn, both reaped and unreaped, covered with snow in
some districts.

The potatoe crop is not heavy, but on the whole nearly free
from the disease which has been so fatal for several years.
Much alarm was caused by the tops of many fields being dis-
coloured by the frost about the middle of September ; but on
examination, the tubers are found to be not much affected.

Wheat is a bulky crop, but does not yield well. Barley
and oats are much below an average bulk.

Live stock is generally healthy, except cattle imported from
Ireland, which are mostly affected with diseases of the lungs.

The heavy rains which fell on the 28th and 29th of Sep-
tember will no doubt be of much use in many ways. The
river Aire, which passes through Leeds, was much swollen,
and its waters gave evident proof of some of the causes of
cholera. At Castleford, whose distance from Leeds is ten
miles, their stench was greater than can be imagined ; whilst
their deleterious contents were such that all the fish were
almost destroyed or taken in a stupefied state, and large quan-
tities floated upon the surface of the water.

At Finsbury Farm, near Romsey, by J. Clark, Esq.

The harvest was well saved, and generally an average crop.
The season has been, and is still, all that could be desired.
Grass and turnips are growing beautifully, and agricultural
operations are proceeding satisfactorily. Some wheat has
been sown on heavy lands in fine order. The early tares,
rye, and clover, are doing well.

To the Report of the Registrar-General are appended the
monthly values at every station, from which the average values
for the quarter have been determined, and which are con-
tained in the following table : —

The mean of the numbers in the first column is 29'576
inches, and this value may be considered as the pressure of dry
air for England during the quarter ending September 30, 1849.

The mean of the numbers in the second column, for Guern-
sey and those places situated in the counties of Cornwall and
Devonshire, is 59°*5 ; for those places situated south of latitude
of 52°, including Chichester and Hartwell, is 60°"1 ; for those
places situated between the latitudes of 52° and 53°, including
Saffron Walden and Leicester, is 58°'4 ; for those places
situated between the latitudes of 53° and 54°, including Derby
and York, is 57°' 1 ; at Liverpool and Whitehaven is 57°*7 j
and at Durham and Newcastle is 55°"8.

The average daily range of temperature in Cornwall and
Devonshire was 12''-9; south of latitude 52° was 19°-3; be-
tween the latitudes of 52^ and 53° was 19°'3; between the

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latitudes of 53° and 54° was 17°'6 ; at Liverpool and White-
haven was 10°-3; and at Durham and Newcastle was 13°*3.

The greatest mean daily ranges of the temperature of the air
took place at Hartwell, Cardington, Ilighfield House, Notts,
and Latimer Rectory ; and the least occurred at Torquay,
Guernsey, Liverpool, and Truro.

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91° at Wakefield; 87° at Chiswell Street, London; 86"-2 at
St. John's Wood ; 86° at Leicester. The lowest thermometer
readings were 29° at Beckington, 33° at Wakefield and at Lei-
cester, and 33°*8 atHighfield House, Notts. The extreme range
of temperature of the air during the quarter in England was
therefore about56°, considering the two extremes as 86°and 30°.

Rain has fallen on the greatest number of days at Stony-
hurst, Highfield House, Notts, Wakefield and Stone. The
average number at these places was 51. It fell on the least
number of days at Southampton, Oxford, Beckington and
Greenwich, and the average number at these places was 29°.
The stations at which the largest falls have taken place are
Stonyhurst, Newcastle, Whitehaven and Helston. The
smallest falls occurred at Beckington, Wakefield, Holkham
and Norwich. The average fall in the counties of Corn-
wall and Devonshire was 9*8 inches ; south of latitude 52°
was 6-9 inches ; between the latitudes of 52° and 53° was 6*9
inches ; between 53° and 54° was 9*3 inches ; at Liverpool
and Whitehaven was 11*5 inches; and at Durham and New-
castle was 10*3 inches.

The numbers in the columns 15 to 19 show the mean values
of the hygrometrical results; from which we find that —

The mean weight of vapour in a cubic foot of air at all
places (excepting Cornwall and Devonshire) in the quarter
ending June 30, 1849, was 4*5 grains.

The mean additional weight recjuired to saturate a cubic
foot of air in the quarter ending June 30, 1849, was 1*1 grain.

The mean degree of humidity (complete saturation =1)
in the quarter ending June 30, 1849, was 0-802.

The mean amount of vapour mixed with the air would have
produced water, if all had been precipitated at one time on the
surface of the earth, to the depth of h'5 inches.

The mean weight of a cubic foot of air under the mean
pressure, temperature and humidity, was 526 grains at the
average height of 155 feet.

And these values for Cornwall and Devonshire were 4*8
grains; 1*2 grain; 0*808; 6*0 inches; and 528 grains, at the
average height of 123 feet.

The following table exhibits the meteorological particulars
of the first three quarters of the years 1847, 1848 and 1849.

Phil, Mag, S. 3. Vol. 35. No. 237. Nov, 1849. 2 B

For the Counties of Cornwall and Devonshire.

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C 374 ]

XLVII. Researches on the Theory of the principal Phcenomena
of Photography in the Daguerreotype Process. By A. Clau-

DET*.

A LTHOUGH the Daguerreotype process has during the
■^^ last ten years been investigated by a great number of
philosophers, and brought to a considerable degree of perfec-
tion by a still greater number of practitioners, it may appear
surprising that the principal phaenomena upon which this new
art is founded, are still enveloped in a mysterious darkness.

My constant endeavour has been to explain them, and at
the tv/o last meetings of the British Association I have had
the honour of communicating the results of some of my re-
searches.

The phaenomena which have not yet been satisfactorily
explained, and of which 1 shall have to treat in the present
paper, are those referring to the following points : —

1. What is the action of light on the sensitive coating?

2. How does the mercurial vapour produce the Daguer-
reotype image ?

3. Which are the particular rays of light that impart to the
chemical surface the affinity for mercury ?

4. What is the cause of the difference in achromatic lenses
between the visual and photogenic foci? why do they con-
stantly vary ?

5. What are the means of measuring the photogenic rays,
and of finding the true focus at which they produce the image ?

At the last meeting of the British Association, which took
place at Swansea, I announced that the decomposition of the
chemical surface of the Daguerreotype plate by the action of
certain rays of light produced on that surface a white precipi-
tate, insoluble in the hyposulphite of soda, which, when ex-
amined by the microscope, had the appearance of crystals re-
flecting light, and which, when seen by the naked eye, were
the cause of a positive Daguerreotype image.

This fact had not been observed before. The opinion of
Daguerre himself and other writers was, that the action of
light on the iodide of silver had only the effect of darkening
the surface, and consequently of producing a negative image.
But it escaped them, that, under the darkened iodide of silver,
another action could take place after a continued exposure to
light, and that the hyposulphite of soda washing could dis-
close a positive image. I have proved this unexpected fact in
obtaining, by the action of light only, and without mercury,

* Communicated by the Author, having been read before the British
Association at Birmingham, Sept. 14, 1849.

On the principal Phcenomena of Photography. 375

images having the same'appearance as those developed under
the action of mercurial vapour. This direct and immediate
effect of light is certainly remarkable ; but the Daguerreotype
process is not founded on that principle on account of the
slowness of its action ; and it is fortunate that, long before
light can produce the white precipitate I have alluded to, it
operates another effect, which is the wonderful property of
attracting the vapour of mercury. This vapour is condensed
in the form of a white powder, having also, when examined by
the microscope, the appearance of reflecting crystals. The
Daguerreotype image is due to this property, which is the
most beautiful feature of Daguerre's discovery.

M. Moser has given an ingenious theory of the action of
mercury. Knowing that the yellow ray had the property of
continuing the effect commenced by light on the iodide of
silver, he has supposed that mercury, when in a state of va-
pour, evolves a latent yellow light, and to the action of that
yellow light of mercurial vapour he ascribes the continuation
of die decomposition of the iodide of silver. But as the ana-
lysis of the surface discloses the presence of mercury, that
metal must have been amalgamated with the silver set free
after the action of light. We must therefore look for another
explanation of the phaenomenon.

It is more probable that light exercises a twofold action on
the iodide of silver, whether it is combined or not with chlorine
or bromine. By one, the iodide is decomposed, and the silver
set free is precipitated on the surface in the form of a white
powder or small crystals ; by the other, which begins long be-
fore the former, the parts affected by light have been endowed
with an affinity for mercurial vapour. •

By means of my photographometer, to the principle of
which I shall presently refer, 1 have been able to ascertain
that the pure light of the sun performs in about two or three
seconds the decomposition of the bromo-iodide of silver, which
is manifested by the white precipitate ; while the same inten-
sity of light determines the affinity for mercurial vapour in the
wonderfully short space of about joV o^^^ P^^*^ "^^ second. So
that the affinity for mercury is imparted by an intensity of
light 3000 times less than that which produces the decom-
position manifested by the white precipitate.

For this reason it is difficult to suppose that the two actions
are the same. We must admit that they are different. Long
before it can effect the decomposition of the surface, light
imparts to the sensitive coating the affinity for mercurial
vapour ; and this appears to be the principle of the formation
of the image in the Daguerreotype process.

376 Mr. A. Claudet on the principal Ph(enomena of

In a paper I communicated to the Royal Society on the 17th
of June 184-7 (see Transactions), and an abstract of which I
read before the Association at Oxford, 1 stated that the red,
orange and yellow rays were destroying the action of white
light, and that the surface was recovering its former sensitive-
ness or unaffected state after having been submitted to the
action of these rays. I inferred from that curious fact that
light could not have decomposed the surface ; for if it had, it
would be difficult to understand how the red, orange, or yel-
low rays could combine again, one with another, elements so
volatile as bromine and iodine, alter they had been once se-
parated from the silver.

But I had not yet been able to ascertain that, when light has
decomposed the bromo-iodide of silver, the red, orange or
yellow rays cannot restore the surface to its former state. The
action of light, which can be destroyed by the red, orange or
yellow rays, does not determine the decomposition, which would
require an intensity 3000 times greater. It is the kind of action
produced by an intensity 3000 times less, giving the affi-
nity for mercury, which is completely destroyed by the red,
orange or yellow rays. It seems, therefore, that I was right
in saying that there was no decomposition of the compound
during the short action which is sufficient to give the affinity
for mercury, and in ascribing the formation of the image only
to that affinity. White light, or the chemical rays which
accompany it, communicate to the surface the affinity for mer-
cury, and the red, orange, or yellow rays withdraw it. 1
must notice here a singular anomaly j viz. that when the
sensitive surface is prepared only with iodine without bromine,
the-red, orange or yellow rays, instead of destroying the action
of white light, continue the effect of decomposition as well as
that of affinity for mercury. Still there is a double compound
of iodine which is far more sensitive than the simple com-
pound, and on which the red, orange, or yellow rays exercise
their destructive action as in the case of the bromo-iodide.

The phaenomenon of the continuing action of the red,
orange or yellow rays, on the simple compound of iodide of
silver, was discovered by M. Ed. Becquerel ; and soon after
M. Gaudin fountl, that not only those rays continue the action
by which mercury is deposited, but that they develope without
mercury an image having the same appearance as that pro-
duced by mercurial vapour.

M. Gaudin, not having observed the fact of the white pre-
cipitate, which is the result of the decomposition by the action
of light, could not explain the cause of the image brought out
under the influence of the yellow ray.

PhotograjiJiy in the Daguerreotype Process, S77

I have observed that the iodide of silver without bromine is
about 100 times more sensitive than the bromo-iodide to the
action of light, which produces the decomposition of the com-
pound forming the white precipitate of silver, while it is 100
times less sensitive for the effect which gives the affinity for
mercury. This seems another reason for supposing that the two
actions are different. It may be that, in the case of the iodide
of silver alone, the decomposition being more rapid, and the
affinity for mercury slower than when bromine is added to
the compound, the red, orange, and yellow rays having to
act upon an incipient decomposition, have the power, by their
own photogenic influence, of continuing the decomposition
when it has begun. This may explain the development of
the image under red, orange, or yellow glasses, according to
M. Gaudin's discovery. But in the case of the bromo-iodide
of silver, the red, orange, or yellow rays have to exert their
action on the affinity for mercury, begun a long time before
the decomposition of the compound ; and they have the pro-
perty of destroying that affinity.

So that it would appear that all the rays of light have the
property of decomposing the iodide of silver in a longer or
shorter time, as they have that of producing the affinity for
mercury on the bromo-iodide of silver; with the difference,
that on the former compound the separate actions of the
several rays continue each other, and that on the second com-
pound these separate actions destroy each other. We can
understand that, in the first case, all the rays are capable of
operating the same decomposition ; and that in the second,
the affinity for mercury when imparted by one ray is destroyed
by another. This would explain the various phaenomena of
the formation of the two different deposits I have described,
and also explain the anomaly of the continuation of the action
of light by the red, orange, or yellow rays, according to M.
Ed. Becquerel's discoveries on the iodide of silver ; and of the
destruction of that action by the same rays, according to my
own observations on the bromo-iodide of silver.

The red, orange and yellow rays, when acting on an un-
affected surface, are considerably less capable than the most
refrangible rays of imparting the affinity for mercurial vapour
on both the iodide and bromo-iodide of silver; and they de-
stroy diat affinity when it has been produced on the bromo-
iodide of silver by the photogenic rays. It follows from this
fact, that when the red, orange, or yellow rays are more abun-
dant in the light than the most refrangible rays, the photo-
genic effect is retarded in proportion to the excess of these
antagonistic rays. This happens when there exists in the

378 Mr. A. Claudet on the pHficipal Phenomena of

atmosphere some vapours which absorb the most refrangible
rays. In these circumstances the light appears rather yellow ;
but it is very difficult to judge by the eye of the exact colour
of the light, and of the proportion of photogenic rays existing
in the atmosphere at any given moment.

The vapours of the atmosphere which render the light yel-
low, act as an}' other medium intercepting the blue rays, and
those which have the same degree of refrangibility. I prove,
by a very simple experiment, the comparative photogenic
action of rays which have passed through such media, and of
those which have met with no similar obstacle; also that media
which intercept the photogenic rays can let pass freely the
illuminating rays.

If I cover an engraving one-half with light yellow glass, and
place it before my camera obscura in order to represent the
whole on a Daguerreotype plate, I find that during the time
which has been necessary to obtain the image of the half not
covered, not the slightest effect has been produced on the half
covered with the yellow glass.

Now if I cover one half with deep blue glass and the other
with the same light yellow glass, the engraving will be seen
very distinctly through the yellow glass, and not at all through
the blue. In representing the whole, as before, on the Da-
guerreotype plate, the half which was clearly seen by the eye
has produced no effect; and the other, which could not be
seen, is as fully represented, and in nearly as short a time, as
when no blue glass had been interposed.

Thus we might construct a room lighted only through an
inclosure of light yellow glass, in which light would be very
dazzling to the eye, and in this room no photographic opera-
tion could be performed ; or a room inclosed by deep blue
glass, which would appear very dark, and in which the pho-
tographic operation would be nearly as rapid as it would be
in open air.

Thus we ma}' conceive certain states of the atmosphere
under which there will be an abundance of illuminating rays,
and very few photogenic rays ; and some others, under which
the reverse will take place.

Considering how difficult it is to judge by the eye alone
of the photogenic state of light, we can understand why the
photographer is constantly deceived in the effect he tries to
produce, having no means to ascertain beforehand, with any
degree of certainty, the intensity of light. For these reasons
I turned my attention to contrive an apparatus by which
I could test at the same time the sensitiveness of the Daguer-
reotype plate and the intensity of light.

Photography in the Daguerreotype Process, 379

I succeeded in constructing an instrument which I have
called a photographometer, the description of which appeared
in the Philosophical Magazine for the month of November
1848.

As I have since improved it considerably, and made with it
a great number of experiments, I shall briefly refer to this
instrument, and describe the useful alterations I have made.

In the instrument described in the Philosophical Magazine
for November 1848, the light struck the Daguerreotype surface
during the passage on an inclined plane of a metallic plate
having seven apertures in a horizontal line,' following the geo-
metrical progression 1, 2, 4, 8, 16, 32, 64; so that the Da-
guerreotype plate being covered with another metallic plate
having four series of seven holes, the effect of light through
every one of the seven holes was represented in proportion to
the opening of the moveable plate. Every one of the four
series of holes indicated the same number of white spots, and
the number of spots was the measure of the light at the mo-
ment. I had four series of holes in order to try several pre-
parations on the same plate, or to test the light on the same
plate at four different times.

The improvement 1 have made consists in my being able to
shut every one of the holes by means of sliding blades ; so
that I can continue, by repeated falls, the geometrical progres-
sion from 1 to 512 on one plate; and when a second plate is
added to the double apparatus, from 1 to 8192. This enables
me to compare and follow the different effects of light in a
considerable range of intensities. This is done in the follow-
ing manner: — After having given one fall with all the slides
open, 1 shut one and give another fall, then shut the second
slide and give two falls, and so on, always doubling the num-
ber of falls for every new slide shut.

It is by this means that I have been able to discover at
what degree of intensity of light the effect called solarization
is produced ; — on well-prepared plates of bromo-iodide it does
not begin under an intensity 512 times greater than that which
determines the first effect of mercury ; — and also at what degree
the decomposition producing the white precipitate without
mercury manifests itself, both on iodide and on bromo-iodide
of silver. On the first, it is 100 times quicker than on the
bromo-iodide; and on the last, it is produced by an intensity
3000 times greater than that which developes the first affinity
for mercury.

The slides enable me to try the effect of different insulated
rays on plates affected by white light. This is done by shut-
ting one-half of each hole in pushing the sliding blades just

380 Mr. A. Claudet on the principal Phcetiomena of

enough for that purpose. In that state I submit the surface
acted on by a great number of intensities of light to the sub-
sequent radiation through red, orange, or yellow glasses, or
any other coloured transparent media, in order to examine
the action of these radiations on one-half of the effects pro-
duced by each intensity of light. By these means I have
found, that before light has decomposed the surface and pro-
duced the white precipitate, the red, orange, and yellow rays
destroy the affinity for mercury, and continue it when the de-
composition has begun.

In the course of my experiments I noticed a curious
fact, which proved very puzzling to me, until I siicceded
in assigning a cause to it. I shall mention it here, because
it may lead to some further discoveries. I observed that
sometimes the spaces under the round holes, which had not
been affected by light during the operation of the photogra-
phometer in a sufficient degree to determine the deposit of
mercury, were, as was to be expected, quite black ; while
the spaces surrounding them were in an unaccountable man-
ner slightly affected by mercury. At first I could not explain
the phaenomenon, except by supposing that the whole plate
had been previously by accident slightly affected by light, and
that the exposure through the holes to another sort of light
had destroyed the former effect. I was naturally led to that
explanation, having before observed that one kind of light
destroys the effect of another; as, for example, that the effect
of the light from the north is destroyed by the light from the
south, when certain vapours existing in the latter portion of the
atmosphere impart a yellow tint to the light of the sun. But
after repeated experiments, taking great care to protect the
plate from the least exposure to light, and recollecting some
experiments of'M. Moser, I found that the affinity for mer-
cury had been imparted to the surface of the Daguerreotype
plate by the contact of the metallic plate having the round
holes, while the space under the hole had received no similar
action. But it must be observed that this phaenomenon does
not take place every time; some days it is frequent, and in
some others it does not manifest itself at all. Considering
that the plate furnished with round holes is of copper, and
that the Daguerreotype plate is of silver plated on copper, it
is probable that the deposit of mercury is due to an electric
or galvanic action determined by the contact of the two metals ;
and perhaps the circumstance that the action does not take
place every time, will lead to the supposition that it is developed
by some peculiar electric state of the ambient atmosphere ; and
by a degree of dampness in the air, which would increase the

Photography in the Daguerreotype Process. 381

electric current. May we not hope that the conditions
being known in which the action is produced, and by avail-
ing ourselves of that property, it will be possible to increase
on the Daguerreotype plate the action of light ? for it is not
improbable that the affinity for mercury imparted to the plate
is also due to some electrical influence of light. How could we
otherwise explain that affinity for mercury given by some rays
and withdrawn by some others, long before light has acted as
a chemical agent?

Photography is certainly one of the most important disco-
veries of our age. In relation to physics and chemistry, it has
already been the means of elucidating many points which had
not been investigated, or which were imperfectly known before.
We may certainly expect that its study will prove of consider-
able use to the progress of these sciences. But it is in reference
to optics that it opens a large field for research and discovery.
Had Newton been acquainted with the properties with which
light is endowed in the phaenomena of photography, there is
no doubt he would have left a more complete theory of light,
and of the various rays which compose it.

Since the discovery of photography, opticians have turned
their attention to the constructing of new combinations of
lenses, in order to increase the illuminating power without
augmenting the aberration of sphericity. It is due to justice
to state here, that the optician who first produced the best
lenses for photography is M, Voigtlander of Vienna, and they
still are the most perfect that a photographer can use, parti-
cularly for portraits. In this country an optician of great
merit, Mr. A. Ross, has constructed lenses on similar prin-
ciples; and at all events has succeeded in producing some
which work as quick, and give an image as perfect in every
respect. In Paris M. Lerebours is renowned for lenses with
larger focus, which are better adapted for taking views than
any I have tried.

From the beginning of photography it was well known that
the effective rays being the most refrangible, had a shorter
focus than those producing white light; and for this reason
Daguerre himself recommended the use of achromatic lenses,
in which all the rays were supposed to coincide nearly at the
same focus. All camerae obscura3 were furnished with achro-
matic lenses, and constructed so that the plate could be placed
exactly at the same distance as the ground glass on which the
image had appeared the best defined. But with these cameras
obscurae it was very difficult to obtain a photographic image
so perfect as that seen on the ground glass ; and it was only
now and then, and as if by accident, that good pictures could
be produced.

S82 Mr. A. Claudet on the pt-incipal PJicenomena of

I soon observed that anomaly, and imagined that it was
due to some errors in the respective position of the two
frames ; one holding the ground glass, and the other containing
the plate, which, by warping or some other causes, might
have been shifted to different distances from the object-
glass.

Not being able to assign another reason for the error, I
constructed a camera obscura in which the ground glass and
the plate were exactly placed in the same frame. In doing
so I hoped to avoid the least error or deviation. But to my
surprise, the more I was correct in my adjustment, the less
I could obtain a well-defined Daguerreotype picture. This
proved lo me that I had to seek for another cause of the diffi-
culty ; and before going any further, I decided to try if the
usual focus did or did not really coincide with the photogenic
focus. For the experiment, I placed at a distance from the
camera obscura several screens on different planes : these
screens being covered with black lines, I could see them very
distinctly on the ground glass. I tried the focus on one of
the screens. To my surprise and delight, I found that inva-
riably the one which had come out well-defined on the ground
glass was confused on the Daguerreotype plate, and vice versa.
This was sufficient to prove to me the cause of the difficulty
I had been labouring under, viz. that the visual focus had not
coincided with the photogenic focus. But the most surprising
feature of that discovery was, that the photogenic focus was
longer than the visual focus. On first consideration it should
have been shorter, as the rays operating in photography are
the most refrangible. Although I could not at first under-
stand the cause of this anomaly, it was sufficient for me to
know that, in order to have a well-defined Daguerreotype
picture, I had only to set the focus on the ground glass for
an object nearer the camera at the distance indicated by the
experiment with the various screens. Continuing my experi-
ment, I found some lenses in which the photogenic focus was
shorter, and some others in which the two coincided.

I communicated a paper on the subject to the Royal Society
and to the Academie des Sciences in May 1844, and from
that time photographers have been able to find the true pho-
togenic focus of their camera ; and opticians, who at first
denied the fact, have at last studied and considered the ques-
tion, trying to construct lenses in which the two foci should
agree.

M. Lerebours of Paris was the first who, on my suggestion,
examined the subject; and he communicated a paper to the
Academie des Sciences, in which he explained the cause of
the difference. He stated that, by altering the proportion

Phologra'phy in the Daguerreotype Process. 383

between the angles inscribed in the curves either of the crown-
or flint-glass, he could render at will the photogenic focus
longer or shorter than the visual focus, and by the same
means could bring them to the same point. There is no ques-
tion that M. Lerebours was right as far as the result referred
to the chromatic correction ; but if, according to the density
of the two glassesjcertain curvatures are required to correct the
spherical aberrations, these curvatures cannot be altered with
impunity only for the purpose of changing the directions of
the most refrangible rays. For this reason 1 have always
preferred lenses in which the spherical aberration is the most
perfectly corrected, without caring whether the photogenic
rays coincided or not with the visual rays, having the means of
ascertaining how I could obtain on my Daguerreotype plate
the best-defined image. In fact, from my own observation
that the red, orange, and yellow rays are antagonistic to the
photogenic rays, and that the last rays have a greater power
when the former are proportionately less abundant, I am of
opinion that when the photogenic rays are only condensed on
the plate, and the others are dispersed on the space more or
less distant from the photogenic point, the action is more
rapid. Rapidity being the principal object in photography,
1 prefer lenses in which the two foci are separated, although
the operation is a little more difficult, and requires consider-
able care.

The question of the photogenic focus is involved in another
kind of mystery, which requires some attention. I have found
that with the same lenses there exists a constant variation in
the distance between the two foci. They are never in the
same relation to each other : they are sometimes more or less
separate; in some lights they are very distant, and in some
others they are very near and even coincide. For this reason
1 constantly try their position before I operate. I have not
been able to discover the cause of that singular phsenomenon,
but I can state positively that it exists. At first I thought
that variations in the density of the atmosphere might produce
the alteration in the distance between the two foci ; or that
when the yellow rays were more or less abundant, the visual
rays were refracted on different points on the axis of the foci,
according to the mean refrangibility of the rays composing
white light at the moment. But a new experiment has proved
to me that these could not be the real causes of the variation.
I generally employ two object-glasses ; one of shorter focus
for small pictures, and the other of longer focus for larger
images. In both the photogenic focus is longer than the visual
focus; but when they are much separated in one they are less
so in the other : sometimes when they coincide in one, they »re

884- Mr. A. Claudet 07i the principal Phcenomena of

very far apart in the other, and sometimes they both coincide.
This I have tried every day during the last twelve months, and
I have always found the same variations. The density of the
atmosphere, or the colour of light, seems to have nothing to
do with the phenomenon, otherwise the same cause would
produce the same effect in both lenses. I must observe that
my daily experiments on my two object-glasses are made at
the same moment and at the same distance for each, otherwise
any alteration in the focal distance would disperse, more or
less, the photogenic rays, which is the case, as I have ascer-
tained. The lengthening or shortening the focus, according
to the distance of the object to be represented, has for effect
to modify the achromatism of the lenses. An optician, accord-
ing to M. Lerebours's calculation, can at will, in the com-
bination of the two glasses composing an achromatic lens,
adapt such curvatures or angles in both that the visual focus
shall coincide with the photogenic focus ; but he can obtain
this result only for one length of focus. The moment the
distance is altered, the two foci separate, because the visual
and photogenic rays must be refracted at different angles in
coming out of the lens, in order to meet at the focus given for
one distance of the object. If the distance is altered, the focus
becomes longer or shorter; and as the angle at which differ-
ent rays are refracted remains nearly the same, they cannot
meet at the new focus, and they form two images. If the
visual and photogenic rays were refracted parallel to each
other, in coming out of the lens they would always coincide^
for every focus; but this is not the case. -j

It seems, therefore, impossible that lenses can be con-,'j
structed in which the two foci will agree for all the various ^
distances, until we have discovered two kinds of glasses, in
which the densities will be in the same ratio as their dispersive
power. There is no question so important in photography as
that which refers to finding the true photogenic focusof every i
lens for various distances. I have described the plan I haven
adopted for that purpose ; by means of that very simple instruri^
ment, every photographer can always obtain well-defined fi
pictures with any object-glasses. But there is another method
of ascertaining the difference between the two foci, which hasj
been lately contrived by Mr. G. Knight of Foster Lane,)t
London. That gentleman has been kind enough to commu-,^
nicate to me the very ingenious and simple apparatus, by,
which he can at once find the exact difference existing be-
tween the visual and photogenic focus, and place the Daguer-
reotype plate at the point where the photogenic focus exists.
1 am very glad he has entrusted me with the charge of bringing
his invention before the British Association. For the scientific

Photography in the Daguerreotype Process, 385

investigation of the question Mr. Knight's apparatus will
be most valuable to tne optician, as it will afford him the
means of studying the phaanomenon with mathematical accu-
»acy.

Mr. Knight's apparatus consists in a frame having two
grooves ; one vertical, in which he places the ground glass,
and the other forming an angle with the first destined to
receive the plate; the planes of the grooves intersect each
other in the middle. After having set the focus upon the
ground glass, this last is removed, and the plate is placed
in the inclined groove. Now if a newspaper or any large
printed sheet is put before the camera, the image will be
represented on the inclined plate ; and it is obvious in its
inclination the various points of the plate will meet a dif-
ferent focus ; the centre of the plate will coincide with the
visual focus by its inclination. It will in one direction meet
the photogenic focus at a point more or less distant from the
centre, if the photogenic focus is shorter than the visual focus,
and in the other direction if it is longer. The frame is fur-
nished with a scale of division, having the zero in the centre.
When the image is represented on the Daguerreotype, by
applying against it anotlier moveable scale of division similar
to the other, the operator can find what is the division above
or under zero at which the image seems best defined ; and
after having removed from the camera the experiment frame,
and set the focus as usual on the ground glass, he has only to
move the tube of the object-glass by means of the rack and
pinion, and to push it in or out, a space corresponding with
the division of the scale indicating the deviation of the true
photogenic focus : the tube of the object-glass is for that pur-
pose marked with the same scale of division.

In order to enable the members of the Association to judge
of the merit of Mr. Knight's invention, I have had his appa-
ratus applied to a small camera with which I made my expe-
riment. By exhibiting at the same time Mr. Knight's method
and my own, a comparison of the two may be made, and
they will be both better understood.

Before concluding, I shall call the attention of all persons
conversant with optics to the singular fact I have observed
respecting the constant variation of the two foci. I have not
been able yet to find its cause, and I leave its investigation to
more competent persons. I hope at the next meeting of the
Association we shall know more on the subject.

Phil. Mag, S. 3. Vol. 35, No. 237. Nw. 1849. 2 C

[ 386 ]
XLVIII. Proceedings of Learned Societies.

ROYAL ASTRONOMICAL SOCIETY.
[Continued from p. 308.]
May 11, f\^ the Determination of the most probable Orbit of a
1849. ^-^ Binary Star from the assemblage of a great number
of observed Angles of Position. By Sir J. F. W. Herschel, Bart.
With some Remarks by the President on a Solution of the same
Problem by M. Yvon Villarceau.

In this paper Sir John Herschel refers generally, for the prin-
ciple of his method, to a paper published by him in the fifth volume
of the Memoirs of this Society, the paper (we may remark) in
which was given an exposition of the principles by which the orbit
of a double star was for the first time actually determined. He
now states his conviction that the method there expounded is, on
the whole, the best that can be employed ; and the object of the
present paper is, retaining the original principle (namely, of using
only the measured angles of position, and rejecting entirely the
measures of distance), and retaining the first step of the original
method (namely, of smoothing down the irregularities of the angles
as -measured, by laying them down graphically, the angles for
abscissae and the corresponding times for ordinates, and then draw-
ing a curve by hand through the points so found, and using that
curve as the representation of the real relation between the angles
and the times, and measuring from it the times corresponding to
angles which differ by 5°, or by 10°, or any other convenient dif-
ference) ; retaining the original method thus far, to complete the
investigation by a process entirely algebraical and arithmetical.

Supposing the times corresponding to equal intervals of angle
to be taken from the curve above mentioned, the next thing required

///
is __ for every 5° or every 10°, &c. This is to be found by the

following formula, which requires for application only the finite dif-
ferences of t for the equidistant values of 9,

rffl A9l 1 2 3 J

The next step is, to infer from this the true apparent distance of
the stars, as it ought to be measured by a perfect micrometer or
measuring instrument. Now every determination of an orbit of
double stars proceeds on the assumption of an attraction between
the two components, and this requires the supposition of descrip-
tion of areas proportional to the time, both in the orbit really
described and in the projection of the orbit which we see. Hence

we must have p^ = constant = 100 (the unit of the radius vector

dt

being for the present arbitrary), and therefore p = \/ \QQ.—^ or=

— 100 -^, according as -— is positive (that is, d increasing in the
M dt

s/

Royal Astronomical Society. 387

direction nfsp) or negative. Sir John adopts for the unit of angles
one degree, and for the unit of time one year.

A series of radii vectores being thus found, corresponding to
certain values of fl, the next step is to form from these in numbers
the corresponding values of the rectangular co-ordinates a^=/3.cosfl
y=p. sin d. And, assuming that the force of attraction between
the two stars follows the law of the inverse square of the distance,
and therefore that the curve really described is a curve of the
second order, and consequently that the apparent curve is a curve
of the second order, we must make these numerical values of x, y,
(as d?i yp J^s ya, x^y^, &c.) satisfy the equation o=-\-\-a.x-\-fly +
yx^ + Sxy + sy-, an equation containing 5 unknown constants. As
the number of equations will generally exceed 5, it will be proper
to combine them by the method of least squares; and the only
question is, what is the function of x and y which shall be supposed
d, priori liable to equal error in all ? Sir John Herschel tacitly as-
sumes that the function B=l + ax + lSy-\~yx^ •^- Sxy + sy'^ is the quan-
tity which with equal weight throughout is to be made as small as
possible, or that 2 (B^) is to be minimum. The equations given by
this consideration are easily formed, and then a, /3, y, S, s can be
determined.

From these numbers the numerical values of the more convenient
elements of the apparent ellipse may be found, and from them the
elements of the real ellipse may be found. The formulae for all
these transformations are given at length by Sir John Herschel, and
they are less complicated than might at first have been feared.

Thus far the elements necessary to produce geometrical coinci-
dence of the concluded orbit with the observed orbit are alone de-
termined. The next operation is to determine those elements which
relate to the motion in the concluded orbit. For this purpose,
angles being taken from the curve based on the graphical projection,
and these angles (which relate to the apparent orbit) being con-
verted into angles in the true orbit by the formulae lately found, and
thus exhibiting true anomalies on the true ellipse, the excentric
anomalies are found at once by the formula u—esinu, and the mean
anomalies are found. Then every one of these angles gives an

equation of the form i ^ i '

^ m;,=A.?i — I,

from the assemblage of which the constants k and / can be found
by the method of least squares ; and then we have all that is re-
quired to form the mean anomaly for any other time t, and conse-
quently (as the elements of the ellipse are known) to form the ex-
centric and true anomalies.

The conversion of a place thus computed in the real orbit into
one in the apparent orbit, and the comparison of the distance com-
puted on the arbitrary scale with the distance measured with the
micrometer, and the inference as to the true value of the units of
the arbitrary scale, are steps which require no particular explana-
tion.

Sir John Herschel holds out the hope of following up this expo-

2 C 2

888 Royal Astronomical Society.

sition with the details of the application of his method to the star y
Virginis.

As an Appendix to Sir John Herschel's paper, it is proper to add
that papers have been received by Sir John Herschel from M. Yvon
Villarceau (namely, a note on the double star X, Herculis, dated 1849,
February 1, a note on the double star ij Coronse, dated 1849, March
30, and a letter dated 1849, April 1, containing an exposition of
M. Yvon Villarceau's methods), which have been communicated
more or less completely to the Academic des Sciences of France,
and which therefore cannot be received in the ordinary way as a
communication to this Society. It is, however, the wish, both of
Sir John Herschel and of M. Yvon Villarceau, and it appears in
every way desirable that their results should be made known to
this Society, both as containing instructive expositions of a very
elegant general method and very curious applications of it, and also
as bearing upon any questions which may arise as to the similarity
or priority of the methods of Sir John Herschel and M. Yvon
Villarceau.

Assuming the law of gravitation, and consequently the law of
elliptic movement, as applying generally to the relative motion of
two stars in a binary system, M. Yvon Villarceau remarks that the
projection of this curve upon the spherical sky (or rather upon a
plane perpendicular to the visual ray) will be a curve of the second
order, whose equation will be,

Y=-ay'^ + bxy + cx"^ + dy + ex ■\-f=o,
the origin of co-ordinates b9ing one star regarded as a fixed centre
of attraction of the other. The object of the next process must be,
to adopt this general equation to the particular observations from
which the orbit is to be deduced : and here it is to be observed
that M. Villarceau does not confine himself either to the measured
angles of position or to the measured distances, but uses both, for
the formation of the numerical values of ,r and y corresponding to
every observation. Having these numerical values of rectangular
co-ordinates, and paying no respect (for the present) to the inter-
vals of time between the observations, the following is the method
used to accommodate geometrically the curve of the second order
to the observed co-ordinates : —

The principle assumed is, that the constants a, h, c, &c. shall
be so determined that if the resulting curve be drawn, and if from
every observed place a normal (usually a very short line) be drawn
to the curve, then the sum of the squares of these normals, each
multiplied by its proper weight, shall be a minimum. This prin-
ciple, it is almost unnecessary to remark, is imperfect, inasmuch as
it does not in any way take cognisance of the laws of movement, as
connected with time; but it will frequently be doubtful, in a pro-
blem of such difficulty, whether it is not best to neglect a condition,
even of the most essential kind, for the sake of making the solution
more simple.

Putting h^ D' for (^)'+ (?")*' »»^ P ^^"^ *^^ ^^^S^^ °^

Royal Astronomical Society, 389

eafch determination, M. Villarceau arrives thus at the following
equations : —

i . — — — =0, or S . i^^ = 0
D« D«

eifF '"• >^^^

S.^=0, or 2.^-^=0 '' ''

&c.,

and he shows how, supposing an ellipse roughly drawn by hand,
the value of D may be found graphically ; and it will then be pos-
sible to solve the equations.

The projected ellipse being thus determined, the real ellipse will
be found from the consideration that the origin of co-ordinates is
the projection of the focus of the real ellipse, while the centre of
the observed ellipse is the projection of the centre of the real ellipse.
The formation of the corresponding equations is a not difficult pro-
blem of analytical geometry. This transformation, however, is not
required till all the other o))erations are completed.

The points determined by observation are not generally found
exactly upon the projected ellipse. In order to have points upon
the ellipse which shall be the subjects of further investigation,
M. Villarceau transfers the observed points to the ellipse by draw-
ing normals to the ellipse, and taking, instead of the point actually
determined by observation, the foot of its normal. If x' and y' be
the co-ordinates determined from observation, x and y those of the
foot of the normal, then

dF
, dx

\dx) \dy )

F(^'.y')

dF
dy

y=y'- '^ . F (x', v')

\dx) \dy)

with sufficient exactness.

The next point is, to introduce the consideration of time ; and
this is to be done by making the areas described by the radius
vector in the projected ellipse proportional to the time. The areas
can be expressed in terms of the corrected co-ordinates and the
constants without much difficulty, the whole of these admitting of
further correction if necessary. M. Villarceau remarks that if there
are four observed places, the solution of the four equations F {x, y)
= 0 will give four of the quantities a, b, c, d, e, in terms of the
fifth ; that these four observations will give three areas between
which there are two equations of proportion ; and that thus, besides

390 R&yal Astronomical Society.

the determination of the fifth coefficient, we shall have an equation
of condition which must be satisfied, or whose failure will prove
that our operations or assumptions are in some part erroneous.
When there are more than four equations, all can be used in methods
analogous to those which are well understood in other investiga-
tions, for correcting the result.

We must, however, express our opinion that this part of the
operation appears the most obscure, as well as the most delicate
and difficult, of the whole.

M. Villarceau remarks that the final determination of elements
will in all cases require observations separated by a considerable in-
terval from the rest,

M. Villarceau has lately communicated to the Academic another
method.

The following are the principal results in the two cases which
M. Yvon Villarceau has specially examined : —

In the instance of ( Herculis, the stars are so unequal that there
can be no possibility of confusion between the two. It was seen
double in 1782, but there is reason to think that it was seen as
only one star between 1795 and 1802, and also between 1828 and
1832. M. Struve, expressing himself very doubtful, seemed to
suppose that the periodic time might be about 14 years. (See the
MensurtB Micrometricce.) A valuable series of observations, how-
ever, having been made at Pulkowa, extending to 1847, the whole
of which have been communicated to M. Yvon Villarceau, he has
deduced from them an orbit in which the excentricity = sin 27°
nearly, and the periodic time is 36^ years. The measure of 1782
and those from 1826 to 1847 appear to be represented with all
desirable exactness. [In comparing the computed and observed
angles of position, we are glad to see that M. Villarceau has con-
verted their eflFects into expressions measured by seconds of arc]
The remarks, too, made by M. Struve about the time of the union
of the two stars observed by him correspond exactly to the positions
given by M. Villarceau's elements. Those of Sir W. Herschel do
not correspond. M. Villarceau suggests that, at a time when the
small star really was hidden. Sir W. Herschel may have been mis-
led by a false image of the large star ; and that, when the image
of the star was deformed, he may have estimated the deformation
in the wrong direction. He desires, however, specially to submit
these conjectures to the judgement of Sir John Herschel ; and we
trust that Sir John Herschel will not decline to undertake the
honourable task to which he is invited.

M. Villarceau concludes with pointing out that this star presents
a remarkable illustration of the amount of uncertainty which may
rest upon the determination of double-star elements, when based
upon a limited series of observations. If we had only to satisfy
the observations extending from 1828 to 1847 (or through more
than one-half of a revolution), we might have represented them by
systems of elements in which the excentricity varies from 0*44
to r63, that is, the orbit might have been an ellipse, a parabola, or
a hyperbola.

Royal Astronomical Society. 391

In the instance of ij Coronse there is a difficulty of a totally dif-
ferent kind. The two stars are so very nearly equal in magnitude
and similar in colour, that, when observations are interrupted for a
long time, it is impossible to say whether that which is adopted as
the zero- star before and after the interruption is the same ; and it
is therefore necessary in some cases to make double computations,
on the two suppositions that the first star, or the second star, is
that to which the measures are referred in other observations.

From the observations to which they had access, M. Struve, Sir
John Herschel, and M. Madler, concluded that the periodic time of
this star was 43 or 44 years, M, Villarceau, however, has had
access to the observations made at Pulkowa from 1826 up to 1847,
and has treated them in the following manner : —

Of fifteen observations, four were rejected, on account of
manifest errors in the distance only. From the remaining eleven,
relations were obtained between the elements, which leave them
dependent upon an indeterminate quantity which is arbitrary be-
tween very wide limits. The observations of Sir John Herschel
in 1823, and of M. Struve from 1826 to 1847, may be represented
with sufficient accuracy by ellipses in which the periodic time
ranges from 38 to 190 years. To fix this indeterminate quantity,
we may take Sir W. Herschel's observation of 1781 or that of 1802
(with a slight alteration sanctioned by Sir John Herschel). If we
fix the indeterminate quantity by the observation of 1802, M. Vil-
larceau finds that the observation of 1781 is also satisfied, provided
that the position of the stars be reversed ; that is, provided that it
be assumed that the other star has been used as the zero, which is
perfectly admissible. Thus is obtained an orbit with a periodic
time of 66 years.

But if we reverse the position of the stars in 1802, which is
admissible, it is found that the observation of 1781 is satisfied
without reversion. The periodic time thus obtained is 43 years.

It is remarkable that in these totally different solutions the
excentricity is sensibly the same, namely, 0"47.

In both cases the remaining errors are so small, in comparison
with the probable errors, as to leave the two solutions equally
entitled to our reception. For the final judgement between them,
M. Villarceau refers to some remarks of Sir W. Herschel, unac-
companied by measures. Although there is some doubt in the
interpretation of these, M. Villarceau thinks that upon the whole
the solution which gives a period of QQ years is the more probable.
He remarks, however, that in four years at the furthest the doubt
will be settled. In 1853'677 the angle of position given by the
66-year solution will be 303° 44', while that given by the 43-year
solution will be 356° 30', leaving a difference upon which there can
be no doubt. The distances will be respectively 0"*51 and 0"*77,
but between these it might be difficult to pronounce.

S9^ Intelligence and Miscellaneous Articles.

CAMBRIDGE PHILOSOPHICAL SOCIETY.

[Continued from p. 231.]

May 21, 1849. — On Hegel's Criticism of Newton's Principia.
By Dr. Whewell.

Parts of Hegel's Encyclopcedia are here examined with the purpose
of testing the value of his philosophy, not of defending Newton.
Hegel says that the glory due to Kepler has heen unjustly transferred
to Newton : confounding thus the discovery of the laws with the
discovery of the force from which the laws proceed, in which latter
discovery Kepler had no share. Hegel pretends to derive the New-
tonian " formula" from the Keplerian law, thus; — by Kepler's law,

A being the distance, and T the periodic time, — is constant : but

Newton (Hegel says) ca^/s —-universal gravitation, whence universal

gravitation is inversely as A^ : — a most absurd misrepresentation of
the course of Newton's reasoning. In the same manner Hegel criti-
cises, and utterly misrepresents Newton's explanation, for the ellip-
tical orbit, of the body's approaching to and receding from the centre;
and of the reason why the body moves in an ellipse. Hegel also
offers his own explanation of Kepler's laws from his own cL priori
assumptions. He says that the motion of the heavenly bodies is not
a being pulled this way or that, as is imagined by the Newtonians ;
they go along, as the ancients said, like blessed gods.

XLIX. Intelligence and Miscellaneous Articles.

RAIN, THE CAUSE OF LIGHTNING.

To the Editors of the Philosophical Magazine and Journal.

Gentlemen, Leeds, October 17, 1849.,,.

S the whole science of meteorology depends upon the number
of phaenomena observed, I am led to trouble you with the fol-
lowing short notice of a phsenomenon which particularly engaged
my attention during its occurrence ; if you deem the communicationiA
worthy to be inserted in your Journal, you will oblige

Your humble Servant,

T. H. Dixon.

A

I observed a paper upon this subject in the Philosophical Magazine
for September last, and it reminded me that I had observed a similar
phsenomenon, of which I made some notes at the time of its occur-
rence.

On the evening of June 4, 1849, a very severe thunder-storm
visited Leeds and the neighbourhood ; my attention was particularly
directed to this storm from a peculiar circumstance connected with

Intelligence and Miscellaneous Articles. 393

"b

it; the storm begun about 9 p.m., and continued until 12, but the
rain did not begin till 1 1 . The whole of the shower which followed
was characterized by the wave-like intensity of the falling rain ;
first the shower began very violently, and gradually got less intense
until succeeded by another sudden increase, and during the whole
storm this increase and decrease could be distinctly marked. I also
noticed a similar circumstance at Redcar in July, and can most cer-
tainly bear witness that in many instances the increase of rain pre-
ceded the flash of lightning, and this occurred many times in suc-
cession. If from observation we find the rain during thunder-storms
has this peculiar characteristic, we may safely consider that rain has
something to do with the production of electricity, but as yet our
observations are so limited, that it would be unsafe to attempt to
form any theory ; but we may hope the phaenomenon will be observed
by others, and also that they will make their conclusions known, and
ultimately we may be led to a new meteorological fact.

ON A COMPOUND OF SULPHUROUS ACID AND WATER.
BY M. DCEPPING.

If sulphurous acid gas, previously washed to get rid of sulphuric
acid, be passed into a bottle containing distilled water, kept cold by
ice, a crystallized substance is formed when a large quantity of sul-
phurous acid has been absorbed.

At a temperature a little above that of melting ice, these crystals
re-dissolve in the surrounding water ; but if the bright liquor be ex-
posed to a temperature somewhat below the point of congelation,
the crystals are again formed in masses consisting of cubes heaped
upon each other.

These crystals may be separated from the liquor at — 3° C, and
may be dried in paper preserved in a perfectly dry phial. Between
— • 1° and — 2°*6, they begin to moisten, liquefy and eventually disen-
gage sulphurous acid. If an attempt be made to dry by the aid of
sulphuric acid under a receiver, at a temperature of — 5°, they de-
compose ; their water is gradually attracted by the sulphuric acid,
and sulphurous acid is disengaged.

In order to determine the proportion of water and sulphurous acid
in these cubic crystals, they were separated from the liquor by a
funnel at the temperature —3° to —4° C. ; and after they had been
well drained, they were submitted to slight pressure in filtering
paper and dried as much as possible. The dried substance was
weighed in a closed tube at a temperature below 0° C, excess of
strong solution of chlorine was added to it, and the solution was di-
gested for some time. By means of chloride of barium the quantity
of sulphuric acid was determined in the form of sulphate of barytes.

I. 2' 157 grms. pressed in filtering paper gave r888 of sulphate
of barytes.

II. r424 gnn. of the same crystals yielded r330 of sulphate of
barytes.

III. 1*625 grm. of these crystals, dried and kept for about 10

394 Intelligence and Miscellaneous Articles,

days in a corked phial at a temperature of from— 3° to— 4°, yielded
1*477 of sulphate of barytes.

One hundred parts of these crystals were then formed of —

I. II. III.

Sulphurous Acid 76-02 79-16 76-82

Water 23-98 20-84 23'18

taking as the basis of the calculation the quantity of anhydrous sul-
phurous acid, corresponding to the sulphate of barytes.

For one equivalent of anhydrous sulphurous acid (H=l) 32-15,
we have —

I. II. III.

Water 10-14 8-46 9*73

These numbers correspond to 1 equivalent of water = 9-01, so nearly,
that no doubt can be entertained of the compound in question being
formed of equal equivalents of sulphurous acid and water.

It appears also that there exists another compound of sulphurous
acid and water. If the liquor which separates from the hydrate in
question, be exposed to a temperature — 6° to — 7° C, it becomes a
crystalline mass which appears to have a lamellar structure. When
the temperature approaches 0°, these crystals re-dissolve, and at
— 2° C. the whole becomes liquid, a phsenomenon which is not ex-
hibited by the preceding compound. The author has not yet ascer-
tained the composition of the last described crystals. — L'Institut,
Octobre 10, 1849.

ON THE METHODS OF ASCERTAINING THE QUANTITY OF
BROMINE IN SOLUTION IN MOTHER-WATERS. BY M. FEHLING.

Three methods are adopted for determining the quantity of bromine
contained in mother-waters or mineral waters.

1st. The first consists in precipitating by nitrate of silver the
chlorine and bromine contained in these liquids, and in treating the
mixture of chloride and bromide of silver by chlorine gas, which
displaces the bromine.

As the atomic weight of bromine is higher than that of chlorine,
the quantity of bromine is readily calculated by multiplying the dif-
ference of weight obtained by the coefficient 1-7947, which is merely
the equivalent of bromine divided by the difference of the equivalents
of bromine and chlorine. This method is not precise except when
the liquids contain a notable quantity of bromine.

2nd. The second process proposed by M. Heine, consists in dis-
placing the bromine by sether, and appreciating the quantity accord-
ing to the intensity of the tint of the ethereal solution.

In operating in this manner on 60 grammes of liquid containing
from 0-002 to 0-020 of bromine, and avoiding the influence of the
sun's rays, the quantity of bromine set free by the chlorine may be
estimated to within about one or two tbousaiadtbs.

Intelligence and Miscellaneous Articles. 395

3rd. Lastly, the third process, which is that proposed by M. Fehling,
is based on the following fact : when a mixture of an alkaline chlo-
ride and bromide is perfectly precipitated by nitrate of silver, the
first portions of the precipitate contain all the bromine which the
solution contained.

This process, therefore, admits of concentrating the bromine, and
employing such a quantity of nitrate of silver as is insufficient to
precipitate the whole of the chlorine ; and as the object is merely that
of obtaining a compound of bromide and chloride very rich in bro-
mide, the first process becomes readily applicable without any risk
of serious error.

The silver precipitate ought to be well washed, and in order to
decompose it by chlorine, it is to be fused, a quantity being intro-
duced into a tube with a bulb, which is to be heated by a spirit-lamp.
— Journ. de Pharm. et de Chim., Septembre, 1849.

DETECTION OF SMALL QUANTITIES OF IODINE.
BY M. L. THOREL.

The method employed by the author for this purpose is the fol-
lowing, and is merely a modified method of using starch. Put into
a small vial fifty or sixty grammes of the suspected liquor, or if it be
a solid body, diffuse it in a small quantity of water ; add six drops of
pure nitric acid, and the same quantity of hydrochloric acid ; a small
piece of paper is then to be covered with a rather liquid prepara-
tion of starch and placed at the mouth of the vial, which is to be
heated. If the liquor contains iodine, either in the state of iodide or
iodate, the paper will assume a violet blue of greater or less inten-
sity. The nitric acid sets the iodine free by decomposing the iodides,
if any exist ; the effect of the hydrochloric acid is, that it is substi-
tuted for the iodine, by decomposing the iodate, if it should be pre-
sent.

If the paper should not become coloured at the moment of ebul-
lition, the same quantity of the two acids should be added, shaking
the vial strongly. In an instant, the spots should appear, and the
stratum of iodine will gradually increase. It must not be immedi-
ately concluded that no iodine is present if no colour appears, for it
is separated with difficulty from certain bodies, as happens with mo-
lasses. In such cases a second operation must be performed, adding
to the liquor ten to twenty centigrammes of tartrate of potash dis-
solved in a small proportion of water. Heat is to be applied an in-
stant before the addition of the acids, which on this occasion may
be used in the proportion of eight to ten drops of nitric acid, and
four drops of hydrochloric acid. After this trial an opinion may be
arrived at with great certainty.

By operating in this manner, the presence of iodine may be de-
tected in a mixture which contains only three to four milligrammes.
With a mixture of twenty milligrammes of iodine and 200 grammes
of salt, very intense spots may be obtained. — Journ. de Chem. Med.,
Septembre 1849.

396 Intelligence and Miscellaneous Articles.

CONTRIBUTIONS TO THE CHEMISTRY OF THE METALS OF
PLATINA. BY M. C. CLAUS.

On examining the residuum of the treatment of platina by its sol-
vent, the author had an opportunity of observing several reactions oc-
curring between the metals of platina and their combinations which
had not been remarked, but which appeared to him worthy of atten-
tion. The following is a sketch of these reactions.

1. Chloride of Iridium and Nitrate of Silver. — It is well known
that the chlorine of the solutions of the various platina metals is not
precipitated as pure chloride of silver by the nitrate. In employing
chloride of iridium, a compound is also obtained, which, according
to the author, is an argento-sesquichloride of iridium, insoluble in
water or in acids, and difficultly soluble in ammonia, but from which
it may always be obtained in the form of rhomboids, as brilliant as
diamonds. M. Claus analysed this saU, and found it to correspond
to the formula 3Ag CI, +lr2 CP.

2. Action of Sulphuric Acid and Sulphite of Potash on the Chlo'
ride and double compounds of some of the Platina Metals. — Sulphu-
rous acid reduces the higher chlorides of the platina metals to a
lower degree; the chloride of platina into protochloride, and the
chloride of iridium to sesquichloride, &c. As to the double salts of
these chlorides, sulphite of potash gives with them a series of com-
pounds of peculiar composition which contain sulphurous acid, com-
municating to them properties which are quite peculiar.

a. Compounds of Iridium — When for the preparation of potassio-
sesquichloride of iridium, eight parts of water are poured upon po-
tassio-chloride of iridium in fine powder, and sulphurous acid is
passed through the liquor till an olive-coloured solution is formed,
the chloride is converted into sesquichloride, accompanied with the
formation of sulphurous and hydrochloric acids. This salt, the com-
position of which is represented by 3K Cl + Ir^ Cl^ + GAq, effloresces
readily in warm dry air ; it is opake, and its crystals become covered
with a bright green powder. It is insoluble in alcohol, soluble in
water, forming an olive-green solution, but by transmitted light it is
slightly purple. It has the bitter taste of chloride of iridium ; but
it is more permanent, and the solution may be evaporated nearly to
dryness without decomposition. The alkalies decompose it with
difficulty. Aqua regia converts it readily into chloride, and nitrate
of silver immediately precipitates, without any blue reaction, the
double salt 3Ag Cl + Ir^ C\\

The solution of potassio-chloride of iridium, reduced by sulphurous
acid, and from which the greater part of the sesquichloride may be
precipitated by carbonate of potash, preserves its olive-green colour
at common temperatures ; but if it be heated, it passes after some
time to a red colour, and eventually to a bright yellow.

It forms also several compounds of peculiar composition, which
contain sulphurous acid, and which, when mixed together, may be
separated, some in the crystalline form and others in that of powder,
by evaporations which are of difficult execution. The author sue-

Intellisence and Miscellaneous Articles. 397

"b

ceeded in isolating three : — 1, a rose-coloured crystalline salt; 2, an
amber-coloured substance, having the consistence of Venice tur-
pentine ; 3, a white pulverulent compound. All these compounds
contain potash, sulphuric acid, chlorine, and protoxide of iridium
in variable proportions. They are nearly insipid, and very slightly
soluble in water, disengage sulphurous acid when heated, and are
difficultly decomposed by calcination.

Hydrochloric acid dissolves them readily, disengaging part of their
sulphurous acid, and converting them into other salts containing an
equivalent of chlorine. The aqueous solution gives a white floccu-
lent precipitate with chloride of barium, and the alkalies decompose
them with difficulty. They are but slowly oxidized by means of
aqua regia; and before conversion into chloride of iridium, they
assume a deep cherry-red colour.

The author has analysed the rose-coloured salt, and finds the
composition to be represented by —

(2K0, S02+2KCl)-f(2lrO J^^qi' j •

The amber-coloured substance resembling turpentine M. Claus
lias also analysed, and gives as its rational formula —

4KO,S02-f-2IrO+ {^^q }*

The white salt of iridium, obtained only in small quantity, has
been described and analysed by the author ; its formula is. —

3K0, SO"'+IrO^ S0"-i-5Aq.

On treating this salt with hydrochloric acid, a yellow solution is
obtained, which by evaporation yields yellow prisms, considered by
M. Claus as a double salt, or sulphite of protoxide of iridium and
chloride of potassium, 3KC1 + Ir0% SO^.

b. Compounds of Osmium. — The potassio-chloride of osmium
undergoes no modification by sulphurous acid at common tempera-
tures ; but when heated, sulphite of potash occasions a partial de-
composition, producing a pulverulent precipitate which is a double
sulphite of potash and osmium, represented by the formula 3KO,
SO'^ + OsOSS02-|-5Aq. On treating this salt with hydrochloric
acid, the double salt, 3K Cl + Os OS SO-, or chloride of potassium
and sulphite of osmium.

c. Compounds of Platina. — The author describes in a few words
the preparation of potassio-chloride of platina, which, heated with
sulphite of potash, serves for the preparation of a white substance,
which the author from his analyses considers as a double sulphite of
potash and platina, 3K0, SO^ + Pt O^ S0^ + 2iAq.; it resembles
the salt of osmium, but is more insoluble, almost insipid, heavier,
and contains only half the quantity of water. With hydrochloric
acid it acts differently from the preceding salts ; for it loses all its
sulphurous acid, and is converted into potassio-chloride of platina.

d. Compounds of Ruthenium. — Sulphurous acid acts but little
upon the potassio-sesquichloride of ruthenium at common tempera-
tures ; but a solution of the salt treated with sulphite of potash

398 Intelligence and Miscellaneous Articles.

becomes of a deeper red colour, and a pulverulent isabella-yellow
precipitate separates from the liquor. This substance, by repeated
solution and crystallization, is obtained of a white colour ; and the
author is of opinion that it has the same composition as the other salts
obtained from the other platina metals ; but the small quantity of
ruthenium which he had at his disposal prevented him from veri-
fying.— L'Institut, Aout 1, 1849.

ON THE COMPOSITION OF HONEY. BY M. SOUBEIRAN.

It has been long known that the honey of the bee contains two
different sugars, one of which is solid and the other liquid. The
former is considered as identical with the granular sugar, which is
slowly deposited from the syrup of raisin-sugar, or in that of cane-
sugar altered by acids. As to the liquid part of honey, it has been
but little studied. M. Biot has, however, stated that it is a sugar
which turns the rays of polarized light to the left.

According to M. Soubeiran, honey contains three different sugars,
namely, granular sugar, or glucose of chemists ; another sugar which
rotates to the right, and is alterable by acids ; and lastly, a sugar
the rotary power of which is exerted to the left, but with an energy
which is nearly double that of altered sugar.

M. Soubeiran has found in common honey, sugar which has rota-
tion to the right, and which can be altered ; but it is especially
abundant in the liquid honey which is contained in the honey-comb.
The proportion is so considerable, that a solution of this honey, which
had a deviation of -|-0"96 towards the right, acquired, by the action
of acids, a contrary rotation equal to — 13*78.

The author describes by the name of liquid sugar of honey, the
fluid portion obtained from honey by the use of the press. His ex-
periments were made upon sugar extracted in 1841, and which has
been kept ever since unchanged and without any indication of cry-
stallizing. This circumstance is sufficient to distinguish it from
altered sugar, which would not have failed to become a solid
mass of granular sugar. Liquid sugar of honey possesses, however,
a number of characters which belong also to cane-sugar altered
by acids ; it is, like it, uncrystallizable, and reducible to a sort of
barley-sugar, which is transparent and solid, but melts with great
readiness. Still further, the liquid sugar of honey is very sensible
to the action of alkalies, and is readily destroyed by them. The
two sugars have the same chemical composition, and combine with
alkalies in the same proportion. This agreement of characters would
tend to confound them, were it not that the liquid sugar of honey
cannot be converted into granular sugar, and that there is a great
difference in their rotary power : this power is almost double in the
liquid sugar of honey.

To recapitulate, the experiments contained in this memoir by M.
Soubeiran establish the following facts : — Honey is composed of a
mixture of three different sugars : one is the granular sugar already
known ; another is the liquid sugar, which resembles in many par-

Meteorological Observations. 399

"to

ticulars cane-sugar altered by acids, but is distinguished from it
in possessing a much stronger rotary power towards the left. The
absolute rotary power of liquid sugar of honey at the temperature of
55° F. for the red ray, and at the length of 100 millims., was found
to be equal — 33*103 towards the left; whilst that of altered
sugar under similar circumstances was found to be equal only to
— 1 8" 933 . The liquid sugar of honey retains its rotary power towards
the left even after it has been rendered solid ; it is one of the few sub-
stances which possess this character. The third sugar which con-
stitutes part of honey is distinguished from granular sugar in being
unalterable by acids, and from liquid sugar in rotating towards the
right. Its proportion is considerable in honey from the comb, di-
minishes by keeping, and even entirely ceases to exist in solidified
honey. — L'Institut, Juin 11, 1849.

METEOROLOGICAL OBSERVATIONS FOR SEPT. 1849.

Chiswick. — September 1. Heavy rain: lightning, with fine rain 10 p.m. 2. Fine:
thunder and lightning, with rain 8 p.m.^ 3. Very fine : lightning, with rain at
night. 4, Fine : cloudy : very clear at night. 5. Hazy : very fine : clear. 6.
Clear and very fine. 7. Cloudy : very fine : cloudy. 8,9. Fine. 10. Cloudy:
heavy showers in the evening. 11. Hazy: very fine : clear. 12. Heavy rain.
13. Overcast : rain : clear. 14 — 16, Fine. 17. Clear and fine. 18. Clear and
cold : cloudy. 19. Very fine. 20. Fine. 21. Showery : fine. 22. Fine. 23.
Dusky haze. 24. Foggy : very fine : clear. 25. Foggy : exceedingly fine.
26. Foggy : fine : clear. 27. Fine : rain at night. 28. Clear : very fine : over-
cast. 29. Overcast : fine : heavy rain. 30. Rain.

iVlean temperature of the month 57°*76

Mean temperature of Sept, 1848 .> 55 '96

Mean temperature of Sept. for the last twenty-three years 57 '23

Average amount of rain in Sept 2*73 inches.

Boston. — Sept. 1. Cloudy : rain p.m. 2. Cloudy : rain early a.m., with thunder
and lightning. 3. Fine : rain early a.m., with thunder and lightning. 4. Cloudy.
5. Fine. 6. Fine : rain p.m. 7,8. Cloudy. 9. Fine. 10. Cloudy : rain a.m.
and P.M. 11. Cloudy. 12. Cloudy : rain a.m. and p.m. 13. Rain : rain a.m.
14,15. Cloudy. 16. Fine: rain a.m. 17 — 20, Fine. 21. Fine : rain and hail
early a.m. 22, 23. Fine. 24. Cloudy. 25 — 27. Fine. 28. Rain : rain a.m.

29, 30. Rain a.m. and p.m.

Applegarlh Manse, Dumfries-shire. — Sept. 1. Dull a.m. : cleared : fine harvest
day. 2. Hail : thunder : rain a.m. : fine p.m. 3. Dew-like shower a.m. : fine:
sultry. 4, 5. Beautiful harvest day : sultry p.m. 6 — 8. Fine. 9. Showery all
day. 10. Very wet a.m. : cleared and fine p.m. 11. Fair a.m.: shower p.m.
and thunder. 12. Fair : dull p.m. 13. Fair: high wind. 14. Dull and threaten-
ing rain, but cleared and was fine. 1 5. A shower : looking unsettled. 1 6. Heavy
rain early A.M. : thunder. 17,18. Fine: very beautiful day. 19,20. Fine:
cloudy : fine harvest day. 21. Fine : cloudy ; bar. falling. 22. Fair still. 23 —
26. Fair. 27. Fair : clear and cold. 28. Rain nearly all day. 29. Rain.

30. Storm of wind and rain.

Mean temperature of the month 53°*5

Mean temperature of Sept. 1848 53 "1

Mean temperature of Sept. for the last twenty-five years . 53 -O
Average amount of rain in Sept. for the last twenty years 3"13 inches.
Sandwick Manse, Orkney. — Sept. 1. Cloudy: drops. 2. Damp. 3, 4. Fog.
5. Bright : cloudy. 6. Cloudy. 7. Clear. 8. Bright : cloudy. 9. Bright :
rain : aurora. 10. Bright : clear : aurora. 1 1. Cloudy : rain : aurora. 12. Rain :
drizzle. 13. Rain : clear : aurora. 14. Bright : showers. 15. Cloudy : clear :
showers. 16. Showers : aurora. 17. Clear : cloudy. 18. Cloudy: rain. 19.
Clear: cloudy. 20. Cloudy: fine: cloudy. 21. Fine: cloudy. 22. Damp:
cloudy. 23. Bright : cloudy. 24. Cloudy. 25 — 27. Bright : cloudy. 28.
Cloudy : damp. 29. Bright : cloudy. 30. Bright : drops : clear.

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THE
LONDON, EDINBURGH and DUBLIN

PHILOSOPHICAL MAGAZINE

AND

JOURNAL OF SCIENCE.

[THIRD SERIES.]

DECEMBER 1849.

L. Observations and Experiments on the Noctiluca miliaris,
the Animalcular source of the Phosphorescence of the British
Seas ; together with a few general remarks on the phcenomena
of Vital Phosphorescence. By James H. Pring, M.D.^

" A third kind of light arises, no doubt, from living animals which float in the
sea, and which must be produced by their peculiar organization, or rather their
component parts, which deserve to be better examined by chemical experiment."
— Tilloch's Magazine, vol. viii. 1800.

THE occasional phosphorescence of ocean-water has been
the subject of observation amongst naturalists from the
days of Pliny down to the present time. The phaenomenon
is peculiar to no sea, and though most brilliant between the
tropics, yet it occurs also in the frozen ocean of either pole,
and, as may be readily inferred, in every intermediate grade
of clime.

Very graphic and highly interesting are the accounts which
travellers and others have given of this remarkable appear-
ance; and various are the opinions which have at different
times been advanced in explanation of its cause.

It has been conjectured that, during the shining of the sun,
light is absorbed l)y the ocean, and that the extrication of it
again renders the water luminous, in a manner analogous to
the action exemplified by Canton's pyrophorus, the Bononian
stones, &c., or to that which has been termed " insolation."

Again, it has been supposed to depend upon a peculiar
electrical state of the atmosphere, or that the ocean itself is at
times capable of manifesting this light, as the result of a highly
electrical condition of its waters; this last opinion, extraor-
dinary as it may now appear, having enrolled the name of
Buffbn amongst its supporters.

* Communicated by the Author, having been read before the British
Association at Birmingham, September 1849.

Phil. Mag. S. 3. Vol. 35. No. 238. Dec. \S\d. 2 D

402 Dr. J. H. Pring's Observations and

The attrition of the saline particles against each other, or
some unknown combination amongst them, has also been re-
garded as a source of this marine light, whilst it has further
been attributed to the presence of phosphoric matter extricated
from decomposing fish, &c.; and lastly, it has been very gene-
rally referred, especially in recent times, to a power of phos-
phorescence possessed by numerous living marine animals,
similar, for the most part, in its character to that exhibited by
the glow-worm and fire-fly on land.

It is almost needless to observe, that, of the foregoing theories,
the last may now be said to be universally admitted as correct;
yet it is surprising that even with some of those who have in-
vestigated the subject in a scientific point of view, no very
distinct ideas seem to be entertained as to the precise nature,
even in the instance of our own seas, of the animalcular source
to which the light is thus in general terms ascribed; whilst
the notions prevalent amongst sailors and others serve only to
exhibit how little has as yet been done towards removing the
popular ignorance in which the subject still remains enveloped.

Amongst the scientific world again, we find that investiga-
tion has chiefly been directed to those instances of vital phos-
phorescence which are presented by that division of the animal
kingdom which is confined to the land; yet this division sinks
into comparative insignificance when contrasted with the great
variety and infinite multitudes of phosphorescent animals which
inhabit the ocean.

With a view, however, to rendering the present notice more
complete, we shall glance rapidly at some of the more promi-
nent instances of phosphorescence as displayed by land ani-
mals, and then notice briefly some of the more important in-
stances afforded by the tribes inhabiting the sea ; dwelling
more particularly, as regards the latter, on the example which
forms the chief subject of the present communication, the
Noctiluca miliaris, to which the phosphorescence occasionally
witnessed in the British seas is mainly attributable.

If we except the instance of the Great American Bittern
amongst birds, which has been stated to possess the power of
" emitting a light from its breast equal to that of a common
torch, which illuminates the water so as to enable it to discover
its prey*," we are not aware that the property of phosphores-
cence has been attributed to any land animals until we descend
so low in the scale as the class of Insects ; a division, however,
in which this jxjwer is very numerously and conspicuously dis-
played, the family of the Lampyridae, or glow-worms alone
containing about 200 species known to be luminous, whilst
* See Loudon's Magazine of Natural History, vol. ii. p. 200.

Experime7its on the Noctiluca miliaris. 403

the number of the Elateridae, or fire-flies, possessing the same
faculty, amounts to at least thirty. Nor are these the only
families endowed with this singular power : it is exhibited like-
wise by the Scarabaeides, and is found also in the Paiims
sphcerocerus, the Scolopendra electrica^ and in several species
of the Fulgorae or lantern-flies. 'J'he ova also of some of these,
as in the Lampyris splendidula, are said to be luminous, and
the pupa and larva of this insect are reputed to possess the
same property, though in a less marked degree. It has been
stated also that the common centipede of this country has
been observed to be slightly luminous, and the same has been
afiirmed of the common earth worm ; but these statements
require further confirmation before they can be received with
confidence.

Before quitting this division of our subject, it may be ob-
served that it is usual, in physiological writings, to find re-
ference made under the present head to the instances of lumi-
nosity in the living human subject which were brought under
the notice of the profession a few years since by Sir Henry
Marsh (Prov. Med. Journ. IS'l-S). The instances in question,
however, though highly interesting to the pathologist, like the
fact remarked by Cabanis of the excess of phosphorus in the
brain of maniacs, are nevertheless of a character which must
exclude them from our present inquiry.

Passing then from the examples of phosphorescence thus
brought rapidly under view, as exhibited by that portion of
the animal creation confined to the land, we proceed briefly
to notice the instances of the same phaenomenon as displayed
amongst the tenants of the deep. And here, as led on in the
pursuit of this interesting subject to seek the ocean as the field
of his further research, the curious inquirer cannot fail to be
struck with the vastness and grandeur of the change presented
to his contemplation. Here he discovers not only a much
greater variety as regards the range and type of animal life
amongst which this power of phosphorescence is distributed,
but he will recognize some individual instances, which, though
so minute as to be revealed only by the aid of the microscope,
yet exist in such countless myriads, that the whole element
may be said to teem with them.

In order to convey some idea of the general effect of the
phosphorescence of the ocean from the presence of a great
variety of luminous animals, and as witnessed on a large scale
at sea, I shall avail myself of some of the descriptions which
have been furnished us by travellers of accurate observation
and authenticity. In a highly interesting narrative of a
whaling voyage round the globe, from the year 1833 to 1836,

2 D 2

404- Dr. J. H. Pring's Observaiio?is and

by F. D. Bennett, Surgeon to the Expedition, we find the fol-
lowing account of the phasnomenon : —

" During a dark and calm night, with transient squalls of
rain, in lat. 43° S. long. 79° W., the sea presented an unusu-
ally luminous appearance. While undisturbed, the ocean
emitted a faint gleam from its bosom, and when agitated by
the passage of the ship flashed forth streams of light which
illuminated the sails, and shone in the wake with great inten-
sity. A net, towing alongside, had the appearance of a ball
of fire followed by a long and sparkling train ; and large fish,
as they darted through the water, could be traced by the
scintillating lines they left upon its surface*." And again,
"At midnight, on the 1st of December, in lat. 19° N. long.
107° W. (half-way between the group of the Revilla-gigedo
and the continent of America), the sea around us presented
one uniform milk-white and luminous expanse, as far as the
eye could see from the mast-head. It emitted a faint light
like that which attends the dawn of day, and bore a near re-
semblance to a field of snow reflecting the rays of the moon ;
the horizon being strongly defined, by the contrast of its bright
and silver hue with the murky darkness of the sky above.
Close to the ship the water appeared brighter than elsewhere,
and the dashing of the waves against her bows produced bril-
liant flashes of light; but it occurred very strangely, that al-
though the waves could be heard lifting in the ordinary man-
ner, it was difiicult to perceive them ; and the sea appeared as
one tranquil unbroken surface. A net and a bucket were
employed to ascertain the cause of this phasnomenon. The
former captured nothing but a few Medusae of no phospho-
rescent power ; and the water taken up by the bucket, though
it was thickly studded by luminous points, contained no tan-
gible bodies.

"A shoal of porpoises came around us at this time; and as
they sported in the luminous ocean, darting rapidly beneath
the surface, their dark bodies enveloped, as it were, in liquid
fire, they tended to complete a scene, which, if correctly pic-
tured, would appear rather as the fiction of a fairy tale than
the effect of natural causes f."

In a small work entitled ' The Ocean,' by Mr. P. H. Gosse,
we have also an interesting notice of the same appearance,
which is thus described : — " The most usual appearances, as
far as they have fallen under my own observation in the At-
lantic, are as follow : — On looking over the stern, when the
ship has steerage-way, her track is visible by a line or belt of
light, not a bright glare, but a soft, subdued, yellowish light,
* Pp. 17-18, vol. i. t Pp. 289, i290.

Experiinents on the Noctiluca miliaris. 405

which immediately under the eye resembles milk, or looks as
though the keel stirred up a sediment of chalk which diffuses
itself in opake clouds through the neighbouring water, only
that it is light and not whiteness. Scattered about this cloudi-
ness, and particularly where the water whirls and eddies with
the motion of the rudder, are seen innumerable sparks of light
distinctly traced above the mass by their brilliancy, some of
which vanish and others appear, while others seem to remain
visible for some time. Generally speaking, both these phae-
nomena are excited by the action of the vessel through the
waves, though a few sparks may be observed on the surface
of the waves around. But now and then, when a short sea is
running without breaking waves, there are seen broad flashes
of light from the surface of a wave, coming and going like sud-
den fitful flashes of lightning. These may be traced as far as the
eye can reach, and in their intermittent gleams are very beauti-
ful ; they have no connexion with the motion of the ship*."

When we inquire more precisely into the particular sources
of this marine light, we find it distributed, as before mentioned,
far more extensively amongst the various grades of animal life
in the ocean, than amongst those of the land. Although the
fact has been somewhat called in question, and the light attri-
buted to the disturbance of the surrounding luminous water,
yet there appears little doubt that the power of phosphores-
cence is actually possessed by animals ranking as high as the
class of fishes. Thus in the narrative of Mr. F. D. Bennett,
above alluded to, after referring the general luminosity of the
ocean on a particular occasion to the presence oi Medusae, he
proceeds : *' Though the discovery of these Medusae was a
satisfactory explanation of the phosphorescent appearance of
the water, 1 liad yet to learn that the latter effect was partly
produced by living, bony, and perfectly organized fish : such
fish were numerous in the sea this night; and a tow-net cap-
tured ten of them in the space of a few hours. They were a
species oi Scopehis, three inches in length, covered with scales
of a steel-gray colour, and the fins spotted with gray. Each
side of the margin of the abdomen was occupied by a single
row of small and circular depressions of the same metallic-
gray hue as the scales ; a few similar depressions being scat-
tered also on the sides, but with less regularity. The exam-
ples we obtained were alive when taken from the net, and
swam about actively upon being placed in a vessel of sea-
water. When handled or swimming, they emitted a vivid
phosphorescent light from the scales, or plates, covering the
body and head, as well as from the circular depressions on the

* Page 365.

406 Dr. J. H. Pring's Observations and

abdomen and sides, and which presented the appearance of as
many small stars spangling the surface of the skin. The
luminous gleam (which had sometimes an intermittent or
twinkling character, and at others shone steadily for several
minutes together) entirely disappeared after the death of the

fish" It is almost needless to observe that there appears
little room for questioning a fact thus minutely and accurately
described. Another instance belonging to the Shark tribe,
(the Squalus fidgens) has also formed the subject of minute
investigation by the same observer. After describing the form
and structure of this fish, and noting accurately the portions
of the body devoted to the production of the light, he remarks,
" 1 am inclined to believe that the luminous power of this
shark resides in a peculiar secretion from the skin. It was
my first im})ression that the fish had accidentally contracted
some phosphorescent matter from the sea, or from the net in
which it was captured ; but the most rigid investigation did
not confirm this suspicion ; while the uniformity with which
the luminous gleam occupied certain portions of the body and
fins, its permanence during life, and decline and cessation
upon the approach and occurrence of death, did not leave a
doubt in my mind but that it was a vital principle, essential
to the oeconomy of the animal."

Many of the Crustacea, of which the Cancer fulgens and the
Oniscus fulgens may serve as examples, are universally admit-
ted to be highly luminous. The Mollusca, both testaceous
and naked, afford well-marked instances of phosphorescence.
Amongst the former, examples of which are somewhat rare,
may be noticed the Cleodora cuspidatay described more par-
ticularly by Mr. Bennett, and also some of the Pholades, &c.;
whilst the latter contain the Salpee, the FyrosomatR, &c.
Amongst the Annelida we find the Nereides and the Polynoe

J'ulgurans enjoying the same faculty; and the same may be
observed very generally of the Acalephae, the general phos-
phorescence of the ocean being chiefly due to the numerous
kinds of Medusae, Poly piferaB,Rotiferae, and Infusoria included
under this class, and more particularly in our own seas to the
microscopic example it contains, the Noctiluca miliaris, which
brings us to the special object of the present communication. ^

In noticing more particularly this minute yet powerful source
of oceanic light, I shall first give a brief account of the general
appearance imparted by its presence to the waters of our bay,
as exhibited for several successive nights during the months of
July and August last, and then describe more particularly the
little animal itself, and the various experiments to which it has
been subjected.

Experiments on the Noctiluca miliaris. 407

Taking, as a good example, the night of the 9th of August
last, which was remarkably bright and cloudless, and at the
same time serene and mild, the phosphorescence of the waters
of our bay, which had been visible in a less degree for many
preceding nights, assumed about midnight a very brilliant
and beautiful appearance. Seen from a distance, the aspect
presented at this time by the whole surface of the water was
that of a diffused silvery light, which caused the dark head-
land of Brean Down, on the opposite side of the bay, to ap-
pear as if laved by liquid silver. On approaching nearer the
water's edge, so as to observe more distinctly the waves as
they broke gently and with even regularity upon the strand,
the effect can only be compared to masses of liquid tire rolling
and pouring in, and diffusing itself along the shore. On the
north-west point of the bay is a projecting rock called Knight-
stone, joined by a raised causeway to the main land, and
forming at high water a sort of short pier, alongside of which
a few small vessels and boats usually lie at anchor. The
shelter against the current, together with the shade afforded
by the rock and walls of the pier, combined to prove highly
favourable to an observation of the effect in comparatively
still water, and under increased darkness. On looking down
then at this point, between the sides of the vessels and the
rock, a constant scintillation was to be observed on the sur-
face of the water, very similar to a shower of fire or sparks,
the luminous points, some larger, others less in size, perpetu-
ally dancing up as it were to the surface, and soon again dis-
appearing to be replaced by others. The larger points, some
of which were as large as a pea, were produced, I conceive,
from several of the little animals having floated into close ap-
proximation or contact, whilst the smaller ones, I imagine,
proceeded from detached individuals.

On striking the surface of the water lightly with an oar,
not only the spot immediately touched, but also all the water
dashed up, appeared, whilst raised in the air, and again on
falling into the surrounding water, to bear an exact resem-
blance to liquid fire, affording a spectacle of the most brilliant
description. Several bottles were then filled with the water
from this spot where it appeared brightest. I likewise pro-
cured a bucketful of the same kind, and the whole was
brought home for the purposes of observation and experiment.
As tending to convey some further idea of the luminous
power of the water in its natural condition, it may be men-
tioned that on rendering my room perfectly dark and agitating
the water in one of these bottles, it perfectly illuminated any
object in its vicinity, so as to enable me to distinguish various

408

Dr. J. H. Pring's Observations and

objects on my table, pictures hanging against the wall, &c. ;
the luminous effect, however, being very transitory, and only
at the moment of agitation.

Viewed the following morning by daylight, innumerable
very minute gelatinous bodies, of a globular form, could be
perceived even with the naked eye, floating near the surface
of the water; and on gently shaking the bottle containing
them, they could be observed to descend to a short depth,
gradually, however, rising again to their former level when
left at rest. From repeated observation of this fact, it would
appear that these little animals are naturally, or otherwise
possess the power of rendering themselves, specifically lighter
than sea water ; and this property appears to be a living attri-
bute, since it ceases, and they are seen immediately to sink to
the bottom of the vessel, upon the occurrence of death.

Placed under the field of a microscope, and magnified to
about the size of a large pea, the Noctiluca presented the ap-
pearance of a highly delicate and translucent membranous
sac, of almost spherical form, and having the look on one side
as if the mouth of the sac had been puckered up and turned
inwards; yet this puckered part does not take an exactly cir-
cular form corresponding to a description which has been
given of it, as "producing such an appearance as would arise
from tying the neck of a round bag and turning it into the
water;" but extends rather in a longitudinal direction, giving
somewhat the effect of a longitudinal cleft ; and fi"om one end
of this cleft is observed to protrude a lengthened filamentous
body, which seems to be a sort of tentaculum, and during the
life of the animal is seen to be in almost constant motion.

I have endeavoured in vain to
obtain a more accurate view of
this appendage; but the state of
constant motion it is in, together
with the extreme minuteness and
delicacy of the whole animal, have
hitherto rendered my efforts un-
availing. That it is occasionally
employed as an organ of locomo-
tion there can be no question, and
some of the movements executed
by it have appeared to me very
surprising. Thus 1 have wit-
nessed it extended above the
animal, and then used as a fulcrum,
as it were, to draw the body of the
animal upwards towards itself; yet

Magnified view of the Noctiluca
miliaria. Natural size, iTrWh part
of an inch in diameter.

Experiments on the Noctiluca niiliaris. 409

by what power so fine and hair-like a member can be made to
oppose such resistance to the water, as that the comparatively
large globular mass composing the body of the animal should
be drawn to it, rather than that it should pass to the globe,
J am unable to determine with precision, and consequently
refrain from offering a merely conjectural opinion.

The method of examination which I have found to be the
most convenient, and from which the foregoing description is
taken, is to pour a small quantity of the luminous water into
a watch-glass and then submit it to the microscope, by which
means the little animals still remain floating in the water, and
their movements, under the eye of the observer, are in no way
interfered with. Examined in this manner, there is nothing
to be discovered to indicate any special luminous organ, or
the precise part of the animal devoted to the production of the
light; but in several specimens I could clearly observe a mass
of loose flocculent mucus adhering to the part which has been
described as being puckered in, and more immediately near
the insertion of the tentaculum; so that I am disposed to
believe that the phosphorescent principle resides in this mucus,
and is probably most vivid at the moment of its secretion, the
secretion itself appearing to be influenced and thrown out
more abundantly under circumstances indicating danger,
serving thus to account for the brilliancy with which the light
is manifested on first agitating the water after it has been
allowed to remain some time at rest. It seems probable, also,
that the motion of the tentaculum may at tifnes contribute
somewhat to the effect, by disturbing the mucus, and thus
bringing a newly-exposed surface of it into contact with the
water ; the occasional scintillations to be witnessed, even where
the water is under circumstances of perfect repose, being, in
all probability, thus produced.

The extreme minuteness and delicacy of this little animal
(its natural size being stated not to exceed the jo^ooth part of
an inch in diameter), have no doubt been the causes that have
interfered to prevent its attracting any great share of popular
attention ; and which have also occasioned its being frequently
overlooked, as formerly stated, even by scientific observers.
Thus, in the passage formerly quoted from the work of Mr. F.
D. Bennett, he mentions that a bucket of water which had
been taken up, " though thickly studded with luminous points,
contained no tangible bodies ;" there can be little doubt that
these " luminous points " were in reality due to the presence
of these minute Noctilucae ; and the same remark may also
be extended to a similar passage which occurs at p. 321, vol. ii.
of the same work. In some cases, on the other hand, it would

410 Dr. J. H. Pring's Observations and

appear that the same animal has been alluded to, but under a
different title. Thus, although, it must be confessed, imper-
fect in its details, no one can read the description given by
Macartney of the Medusa scifitillans, without recognizing its
full applicability, as far as it goes, to the subject of the present
notice. Two other instances, the Medusa hemispharica and
the Bero'e fulgens, are also described by Macartney as occa-
sionally to be met with in the British seas ; but their compa-
rative rarity has led this author himself to regard the minuter
example, of which we are now treating, as " the most frequent
source of the light of the sea around this country," and even
also " in other parts of the world." Passing, then, from these
general considerations as regards the animal itself, we shall
proceed to detail the various experiments to which it has V)een
subjected, which may be most conveniently treated of in the
following order, viz. — I, experiments subjecting the luminous
water to the action of galvanism ; 2, to the action of various
gases ; 3, to the action of the strong mineral acids ; 4, to the
action of aether and chloroform, &c.

1. Effects of Galvanism and Electro magnetism. — Subjected
to a simple galvanic current from two of Smee's batteries, no
very perceptible effect could be observed to be produced. I
then attached an electro-magnetic coil to the batteries, and
thus passed the electro- magnetic current through the water
for some time: at first no very appreciable result appeared to
follow; but in a short time a steady and continued glow of
light was given out from the whole of the water, the surface
of which appeared further as if spangled with numberless
minute but persistent points of light. After a short time the
light began to grow more faint, and in a quarter of an hour
had ceased altogether, without the possibility of its being re-
produced, the loss of the light being evidently dependent upon
the death of the animalculae.

2. Gases. Effects of Oxygen. — On filling a bottle with oxy-
gen gas, and allowing some of the gas to escape so as to be
replaced by a portion of the luminous sea-water, the phos-
phorescence of the Noctilucae contained in the latter could be
perceived to be sensibly increased when the water was agitated
with the oxygen, but no continuous or persistent glow of light
followed this experiment. For upwards of a week, however,
the little animals continued to live beneath this atmosphere of
oxygen, evidently emitting, on agitation, for several successive
nights during which the observations were continued, the same
tmount of increased light as had been observed to occur in

he first instance.
Effects of Nitrogen. — Subjected to the influence of nitrogen,

Experiments on the Noctiluca miliaris. 41 1

in the same way as has just been described with respect to
oxygen, the results were much less marlced than might have
been anticipated. The Noctihicae confined beneath the ni-
trogen continued to live, and to display a vivid phosphores-
cence when the bottle was agitated for above the space of a
week after the experiment was first instituted. If any differ-
ence could be observed between this experiment and the former,
it was that the brilliancy of the light was somewhat less in this
than in tlie former, being probably about equal to what it
would have been if atmospheric air had been employed in
place of nitrogen.

Effects of Nitrous Oxide Gas. — On being submitted in the
same manner to the action of this gas, the Noctilucae appeared
to be no otherwise affected than under a similar employment
of atmospheric air. They were alive and phosphorescent at
the end of ten days from the commencement of the experiment.
The intensity of the phosphorescence, however, appeared to
be neither augmented nor diminished by the action of this
gas.

Effects of Stdphuretted Hydrogen Gas. — On treatnig a por-
tion of the luminous water with this gas, the phosphorescence
was instantly destroyed, all the Noctilucae being immediately
killed ; thus further demonstrating and establishing the well-
known power of destructiveness to animal life which charac-
terizes this gas.

Effects of Carbonic Acid Gas. — Of all the gases hitherto
noticed, the carbonic acid is the most remarkable in its effects
on the luminous sea water. Having filled a bottle with this
gas, and introduced it under the water so as to allow a por-
tion of the gas to escape and be replaced by the water, in the
same manner as in the other instances just related, the lumi-
nous property of the water was not only brought out and
highly increased, but was rendered permanent for at least a
quarter of an hour, during which time the effect might be
compared to a bright incandescent glow, of sufficient inten-
sity to render the bottle visible from a distant part of the
room ; and when approached more nearly, to enable me to
discern the hands of a watch by the sole aid of the light thus
afforded. At about the expiration of fifteen minutes the light
became gradually fainter, and in about twenty or twenty-five
minutes had totally ceased ; the darkness, as in the other cases,
being evidently connected with the death of the animalculae,
which on being brought into the light, could be seen lying at
the bottom of the vessel.

A second bottle of this gas was then procured and employed
in the same way, for the purpose of ascertaining the effect of

412 Dr. J. H. Pring's Observations a?id

the admission of atmospheric air, at the time when the phos-
phorescent glow was beginning to grow faint. The result,
however, did not appear to be in any way influenced, nor was
the light in any degree resuscitated by this variation of the
experiment.

Effects of Hydrogen. — Submitted to the action of this gas,
no very marked effect appeared to be produced upon the water.
On agitating a portion of it in a bottle containing this gas,
numerous specks of light, indicating the presence of the ani-
malculae, could be perceived for many successive nights ; but
the light appeared somewhat less vivid in its character than
that afforded with atmospheric air, or in the instance before
mentioned, in which pure nitrogen was employed.

Effects of Atmospheric Air. — The influence of atmospheric
air is here introduced merely as affording a standard of com-
parison with the effects obtained from the employment of the
gases. A bottle of the luminous water, procured at the same
time as that used in the preceding experiments, retained its
luminosity a few days longer when subjected only to atmo-
spheric air, than under the eniployment of any of the above-
mentioned gases ; but the phosphorescence was only to be
observed on the occurrence of any agitation of the water. It
appears also that the luminous property is retained longer
when the vessel or bottle containing the water is kept closed
or corked, than when it is left entirely open and freely ex-
posed to the action of the air.

3. Effects of the strong Mineral Acids. — For the purpose of
ascertaining whether the phosphorescence would be in any
way affected by the strong mineral acids, a small quantity of
water was placed in each of three glass vessels, and then a few
drops of acid were added to the water in each vessel, this
latter part of the experiment being of course conducted in the
dark. On letting fall a few drops of strong sw//;^M;7cac/W into
the water, the latter immediately emitted a bright light which
remained for the space of a minute or two, after which it
almost immediately disappeared.

The effect of strong nitric acid appeared in no way to differ
from that produced by the sulphuric acid; but treated with
strong hydrochloric acid in the same manner, the increased
luminosity of the water was much less conspicuous than in
either of the former instances, and the darkness ensued almost
instantaneously.

Effects qfJEther and Chloroform. — A few drops of aether
dropped into the sea-water in the dark appeared instantly to
deprive it of its luminous property, no degree of agitation to
which it was subjected being found capable of eliciting the

Experiments on the ^ociWiicsi m\\\av\s. 413

smallest scintillation after the acklition of the aether. On sub-
stituting chloroform, however, in the second experiment in
the place of the aether, a very bright and persistent phospho-
rescence was given out for the space of a few minutes, after
which the water speedily became dark, the animalculae being
evidently killed. Before taking leave of this division of the
subject, it may be as well to notice the influence simply of
fresh water upon the Noctilucae. On pouring some of the
sea-water, rendered luminous by the presence of these little
animals, into a vessel already containing some fresh rain-water,
a subdued continuous glow was given out from several lumi-
nous points for a short period, during which the specks of
light were seen to subside to the bottom of the vessel, and
very speedily afterwards to become totally extinguished.

Of the foregoing experiments, those connected with the em-
ployment of the gases appear to be the most interesting; and
any degree of importance they may possess will be best ap-
preciated from their bearing upon the topics now to be brought
under notice, in the form of a few concluding remarks of a
general character on the

Phceiiomena of Vital Phosphorescence. — The development of
light as the result of a vital function, and as constituting an
essential feature in the oeconomy of some forms of animal life,
is a phaenomenon of so interesting and remarkable a nature,
that it could not fail to arrest the attention of naturalists and
philosophers in almost every age. It is, however, only since
the impulse which the cultivation of chemical science received
about the latter part of the last century, that the subject has
come to be investigated in the true spirit of scientific inquiry.
It was about the period here alluded to, also, that the animal-
cular source of the phosphorescence of the sea was first in-
disputably established; and some valuable papers appeared
on the subject in the excellent journal conducted by Mr.
Tilloch. At this time, however, no higher object appears to
have been sought, than the mere establishment of the fact, as
just stated, of the dependence of the phosphorescence of the
sea upon an animalcular origin. Many individual instances
of phosphorescent marine animals were, indeed, adduced in
support of the new doctrine ; but this was done without much
method or accuracy of detail; and the minuteness and trans-
parency of the little animal which forms the subject of the pre-
sent notice appear to have occasioned its being at that time
overlooked.

At a period, then, when the fact of the animalcular source of
marine phosphorescence was barely admitted, and may be said
to have been almost a question still subjudice, it was scarcely

414 Dr. J. H. Pring's Observations atid

to be expected that those forms of animal life, whose very ex-
istence was held to be problematical, should themselves be
made the subjects of actual experiment; and it is accordingly
among those more undoubted and eas>iiy accessible examples
afforded by the insects to be found on the land, that the study
of the phaenomena of vital phosphorescence has been chiefly
prosecuted ; the glow-worm and the fire-fly having been
generally selected for the purposes of experimental investiga-
tion, from the period in question even down to the present time.

Thus, in the second edition of Chaptal's Chemistry, pub-
lished so long since as the year 1795, we read that " Mr.
Forster of Gottingen found that the light of glow-worms is
so beautiful and bright in oxygenous gas, that one single in-
sect was sufficient to afford light to read the Armo?ices Savantes
of Gottingen, printed in very small character." The same
fact is likewise referred to, and ably commented on, in an
excellent paper on the phosphorescence of the Luciole {Lam-
pyris Italica) by Dr. Carradori, in the second volun)e of Til-
loch's Magazine; and similar notices are thus incidentally to
be met with interspersed throughout the mass of physiological
and chemical writings with which science is now enriched. It
is, however, to Professor Matteucci that we are indebted for
the most accurate and comprehensive experiments that have
hitherto been undertaken in connexion with this department
of inquiry ; and although still confined principally to the glow-
worm, his observations may fairly be assumed to afford the
best exposition of the existing state of knowledge on the sub-
ject of phosphorescence now extant; and I must accordingly
refer to his valuable lectures, as published by Pereira, all
those who may be desirous of becoming acquainted with the
minute structure of the phosphorescent organs of the glow-
worm, and such other topics as do not appear to fall strictly
within the design of the present paper.

On comparing the results obtained from the action of va-
rious gases on the Noctiluca, as described in a former part of
this communication, with the effects produced by the same
agents upon the glow-worm as recorded by Professor Mat-
teucci, some very remarkable differences will be found to pre-
sent themselves to our observation. It is right, however, to
bear in mind the different circumstances under which the ex-
periments are necessarily conducted in the two instances; the
animalculae in the former, being brought into contact with the
gas only through the medium of the water in which they float;
whereas in the case of the glow-worm, the insect is freely and
entirely exposed to the gas in which it is immersed.

Bearing in mind^ then, and making suitable allowance for

Experiments on the Noctiluca miliaris. 415

this difference of circumstance in the two instances, we shall
proceed to note some of the more remarkable points of con-
trast which they present to us, and which may be thus sum-
marily enumerated.

As in the instances recorded by Matteucci and other ob-
servers, with respect to the glow-worm, so with regard to the
Noctilucae under consideration, the phosphorescence was found
to be remarkably increased hy oxygen ; in the former, how-
ever, not only was the light increased in brilliancy, but also
in duration ; whereas we have seen that the Noctilucae, con-
fined under an atmosphere of oxygen, died somewhat sooner
than those confined in a bottle containing atmospheric air.

In hydrogen, glow-worms are found to lose their phospho-
rescence at furthest in about twenty-five or thirty minutes;
whilst the Noctilucae, under an atmosphere of this gas, con-
tinued to emit scintillations at the end of eight or nine days
from the commencement of the experiment. But it is in re-
spect to carbonic acid gas that the most remarkable contrast
is exhibited in the two cases. On placing glow-worms in this
gas. Prof. Matteucci found that in a few minutes the light en-
tirely disappeared; whereas, in the case of the Noctilucae, we
have seen that there is no agent which has the effect of in-
creasing the brilliancy of the light so powerfully as this gas,
at the same time that the bright phosphorescent glow formerly
described is rendered permanent for the space of fifteen or
twenty minutes. After the lapse of this time, however, this
gas proves as fatal to the Noctilucae, as to the glow-worm ; and
to the former, without the power exhibited by the latter, of
resuscitation of the light by the admission of atmospheric air.

The effects of sulphuretted hydrogen gas appear to be pre-
cisely the same on the glow-worm and on the Noctiluca, both
being very speedily destroyed by it.

Although those which have now been cited appear to be the
only instances which offer a fair opportunity for direct com-
parison, yet there are several other points which seem natu-
rally to demand notice in this place in connection with the
experiments formerly detailed. The phaenomenon of vital
phosphorescence has been regarded as presenting an analogy
to the function of respiration, if not connected with it. Thus,
in a paper in Tilloch's Magazine (vol. x) on the Phosphores-
cence of Ocean- water by Prof, Mitchell of New York, we
find the maintenance of the process of phosphorescence
ascribed to the presence of a supply of oxygen as conveyed by
the arterial blood, the process in fact being compared to re-
spiration as expressed in the following somewhat curious pass-
age : — " The light, then," says he, " which these marine ani-

4- 16 Dr. J. H. Pring's Observations and

mals (the larger Medusae) exhibit, may be concluded to be
produced by a function in them analogous to the respiration
of animals which are of larger size and more complicated
structure. The only reason why it is visible From their bodies
is, that the gelatinous matter of which they consist is transpa-
rent. It is not improbable that the same phaenomena would
be as obvious in the bodies of other creatures, and even of
human beings, if the opacity of the materials of which we con-
sist did not hinder the light within us from shining so as to be
seen."

From the opinion expressed by Matteucci, he would appear
to compare the process of vital phosphorescence to a species
of combustion, in which however he also recognizes the ne-
cessity for the presence of oxygen. In commenting on the
various experiments to which he subjected the phospho-
rescent matter, he observes, " From all these experinients, I
conclude that carbonic acid is produced by the contact with
oxygen of the phosphorescent matter alone, separated from
the rest of the animal; that the light ceases to be produced
when this gas is not present, and that by the contact of the
latter, light and a volume of carbonic acid, equal to that of the
oxygen consumed, are produced ; and that the phosphorescent
substance of this insect, when not luminous, does not act on
oxygen. It is therefore natural to suppose that the luminous
segments of theseanimals,beingenveloped by transparent mem-
branes, and by means of the numerous tracheae discovered
here and there in these animals, atmospheric oxygen is brought
in contact with a substance, sui generis^ principally composed
of carbon, hydrogen, oxygen and azote." And again, " The
example of an organic substance which burns in the air by
absorbing oxygen and emitting carbonic acid, is not new ; this
is the case with decaying wood, with oiled cotton, with finely
pulverized charcoal, and with many other substances liable to
spontaneous combustion."

On this question, however, there appears to be some ground
for a difference of opinion. The experiment in which the Noc-
tilucae continued for many clays to emit very vivid scintilla-
tions when confined beneath an atmosphere of nitrogen, must
be held to militate against the preceding explanation. It is
asserted also by Carradori, that the Luciole will shine in a
barometrical vacuum, but the experiments of Matteucci on the
same point limit this effect to two or three minutes. Admit-
ting therefore the correctness of the latter observation, it may
still be questioned whether the effect, even for the time here
specified, can be wholly ascribed to the presence of oxygen.
Again, when operating on the phosphorescent matter only of

EA'penmenls on the "Noctiluca mWiaris. 417

the glow-worm, this matter being separated from the entire
insect, it was found by Matteucci to retain its luminous pro-
perty for thirty or forty minutes after it was placed in pure
hydrogen or carbonic acid gas. Here then we have the phos-
phorescence continued much longer than in the case of the
barometric vacuum; and where, it may be asked, was the
supply of oxygen that maintained the combustion above half
an hour in this instance, or how can this fact be reconciled
with the statement formerly cited, " that the light ceases to
be produced when this gas (oxygen) is not present?" In re-
ference to the same point, I may here advert to the increase
of light from the effect of carbonic acid on the Noctilucae for-
merly described, and may quote also an experiment from the
observations of Macartney, in which he states, " Some of the
scintillating and hemispherical species of Medusa, contained
in a small glass jar, were introduced into the receiver of an
air-pump, and the air being exhausted, they shone as usual
when shaken; if any difference could be perceived, the light
was more easily excited, and continued longer in vacuum*."

A consideration of these and some similar facts would tend
rather to the conclusion drawn by Carradori in reference to
the experiments of Forster formerly quoted, on which it is
remarked, in the 2nd vol. of Tilloch's Magazine, " The ob-
servation made by Forster, that the Luciole diffused a more
vivid light in oxygen gas than in atmospheric air, does not,
according to Carradori, depend upon a combustion more ani-
mated by the inspiration of this gas, but on the animals feel-
ing themselves, while in this gas, in a better condition ; " — a
conclusion, which seems to furnish a view of the question of
sufficient importance, to say the least of it, to merit some no-
tice. On the other hand, the instance of the detached lumi-
nous segments placed under oxygen, and appearing to absorb
a portion of the gas, lends weight to the opinion of Matteucci.
It appears, however, by no means certain, even in this case,
that the oxygen found to be absorbed, had actually entered
into combination with those particles only which are imme-
diately concerned in the production of light; it may, on the
contrary, be supposed to have been absorbed also, if not prin-
cipally, by the other constituents of the organic matter with
which the immediate light-emitting particles are combined.
And this brings us now to the consideration in the next place
of the

Chemical Nature of the Phosphoresce7it Matter. — In the
earlier inquiries respecting the proximate cause of vital phos-
phorescence, we find that the actual presence of phosphorus
• Phil. Trans. 1810, part 1. p. 285.

PhiL Mag. S. 3. Vol. 35. No. 238. Dec. 1849. 2 E

418 Dr. J. H. Pring's Observations and

in some form of combination was deemed necessary to the
display of the luminous property, and in fact that this sub-
stance was regarded as the essential ingredient entering into
the composition of the phosphorescent matter. Thus it is
stated by Carradori, " Behind this receptacle is placed the
phosphorus, which resembles a paste having the smell of
garlic, and very little taste*." Again, we find Chaptal
speaking of it without any hesitation as a phosphoric oil.
After noticing the solubility of phosphorus in oils, and more
especially in the volatile oils, he observes, " The combina-
tion of phosphorus and oil appears to exist naturally in the
glow-worm, Lampyris splendidula, Linnaei. Forster of Got-
tingen observes that the shining matter of the glow-worm is
liquid. If the glow-worm be crushed between the fingers, the
phosphorescence remains on the finger f."

More recently, again, we find Miiller enumerating several
facts bearing on the subject, and deducing from them the fol-
lowing conclusion : — " From all the above facts, the opinion
of Treviranus appears most probable; namely, that the light
is derived from a matter containing phosphorus, which is
formed under the influence of light, but, once formed, is in
some measure independent of light J." Nor am I indeed
aware that this notion of the actual presence of phosphorus
in the phosphorescent matter of living beings, has ever, pre-
viously to the observations of Matteucci, been entirely re-
jected.

After detailing the influence of the various reagents em-
ployed in an elaborate chemical examination of the phospho-
rescent matter, Matteucci observes respecting it, — " It does
not present any obvious trace of phosphorus ; of this fact I
have assured myself by calcining this matter several times in
a platinum crucible, and by treating the dissolved residue with
the tests which indicate the presence of the phosphates. From
all we have now stated, we can no longer regard the presence
of phosphorus as the cause of the light in these insects^;"
and in another place, as before mentioned, it is said to be " a
substance, sui generis, principally composed of carbon, hydro-
gen, oxygen and azote."

On a point like the present, however, where the statement
just mentioned is so entirely in opposition to all previous ob-
servation, it would seem desirable that we should know with
certainty what is the smallest possible amount of phosphorus
which is capable, when placed under the most favourable cir-

* Tilloch's Magazine, vol. ii. p. 79.

t Elements of Chemistry, vol. iii. p. 362.

j Elements of Physiology, vol. i. p. 103. § p. 182.

Experiments on the Noctiluca miliaris. 419

cumstances of combination, of giving rise to the phaenomena
of phosphorescence. The experiments on which Matteucci
grounds his opinion, were no doubt very carefully conducted ;
yet it may be questioned whether a different result might not
be obtained, could a test of such extreme delicacy be rendered
applicable in this instance, as we are furnished with by Marsh's
apparatus in respect to arsenic. Whilst still upon this sub-
ject, I may mention that experimenting some years since with
a view to test the theory of the luminous matter of the glow-
worm being a natural phosphoric oil, and at the same time to
imitate artificially the experiment of Forster, I enclosed some
phosphoric oil in a delicate membranous sac, which I then
introduced into oxygen gas. The result however was any-
thing but favourable to Chaptal's theory, since the phospho-
rescence, which had been well-marked whilst in atmospheric
air, ceased immediately upon the immersion of the bladder in
oxygen.

It has been supposed by many experimenters that vital
phosphorescence is remotely connected with, or dependent
upon, the action which is termed "insolation"; and although
we find experiments detailed by Matteucci which at first in-
clined him to this opinion, yet, on a more careful and exact
repetition of them, he was led to admit that " when the insect
is placed in its natural conditions with regard to temperature,
humidity, &c., and continues to be nourished, the phosphores-
cent matter is preserved independent of solar action," a con-
clusion with which the result of the observations made by
myself, in the case of the Noctilucae, entirely corresponds.

In reverting here to the experiments on the Noctilucae, it
may be observed that the medium in which they live gave an
opportunity for certain experiments which cannot be obtained
in the case of the glow-worm — I refer more especially to the
influence of galvanism and electro-magnetism formerly de-
scribed. From the agency of the former however we have
seen little or no effect to be produced ; whilst the influence of
the latter appeared to be only of the nature of a powerful
stimulus, not dissimilar in its character from that produced
by the strong mineral acids.

An experiment may also be mentioned here, a notice of
which, from its negative character, was omitted in its proper
place ; and is now briefly introduced lest it should be sup-
posed, from the omission, to have been overlooked — I allude
to the effect of temperature on the luminous sea-water. On
placing a bottle of the sea-water in a vessel containing com-
mon spring water at the temperature of 90°, no remarkable
effect or increase of light was to be observed ; and it has been

2 E2

420 Dr. J. H. Pring's Observations and

remarked, on the other hand, that when the sea-water is con-
verted into ice it still retains its luminous property.

It now remains only to offer a few words with respect to
the

Use of vital phospJwrescence, a subject, which, as it has
already proved the fertile source of a great amount of specu-
lation, more remarkable for its ingenuity than for any more
satisfactory result, it will be my endeavour to dismiss without
increasing the accumulated mass of conjecture with which it is
already encumbered. As the instances of vital phosphorescence
occur amongst so varied and wide a range of the animal crea-
tion, it is only reasonable to infer, that in different individual
instances this faculty will serve respectively a different pur-
pose. Thus in the highly predaceous luminous shark, the
SqualusJulgenSf formerly noticed, it may readily be assumed
with Mr. Bennett*, "That the phosphorescent power it pos-
sesses is of use to attract its prey, upon the same principle as
the Polynesian islanders and others employ torches in night
fishing." In the insect tribe, again, it has no doubt been
correctly described as furnishing " a la lettre, le flambeau de
I'amour."

Amongst the lower marine tribes, however, the object of
this luminous provision is generally admitted to be much less
apparent ; and the most probable conjectures that have been
formed respecting it, are those by which it is regarded as an
engine of defence. Mr. Kirby appears to have viewed it alto-
gether in the latter light; upon which Mr. Bennett has the
following remark : — " I cannot believe, with Mr. Kirby, that
it serves as a mode of defence; because from what we know
of the nature of fishes, this refulgence would be one of the
surest means of bringing their probable enemies upon them ;
and if we are to regard the oeconomy in a destructive point
of view, we might rather suppose that it is intended to direct
the nocturnal predaceous fishes to their food. * * * But it
would be unjust to accuse Nature of thus wantonly investing
her creatures with a charm that can only tend to their destruc-
tion f." The train of argument here employed may be cited
as an example of the uncertainty and perhaps error into which
the mind may be betrayed, when it quits the plain and sober
path of reason, to wander in the field of mere conjecture.

In the instance of the Noctiluca, as already hinted, and for
the reasons formerly assigned, it seems probable that this
luminous property serves the purpose of defence; though whe-
ther this is its sole object, is a question for future investigation
to determine.

• Vol. ii. p. 258. t Vol. ii. p. 325.

Experiments on the Noctiluca miliaris. 421

Whilst then we have thus cursorily glanced at some of the
theories which have been advanced on this subject, we are
compelled to confess that even those best established amongst
them are far from being in any degree satisfactory. In the
instance of the glow-worm, for example, the purpose which
this provision fulfills may be said to be universally admitted
and agreed upon ; yet what sufficient reason can be assigned
for such a faculty being conferred almost exclusively on this
insect, in preference, as it were, to all others? On this head
one cannot do otherwise than express an entire concurrence
in the conclusion of Matteucci, that this phenomenon, " in its
exceptional character, is one of those mysterious singularities
which Nature seems to have distributed amidst the immense
variety of beings, almost without any previous attention to the
animals on which she bestows them, as if merely for the pur-
pose of constraining us to admire with humility the power of
her creative skill."

In concluding this brief and imperfect sketch of a subject
involving so many points of interest, my object will have been
attained, if what has been here advanced should serve the pur-
pose of rendering somewhat more defined the outline of a pic-
ture which yet remains to be filled up in its details, and still
invites the hand of the more skilful artist to the undertaking.
The subject of vital phosphorescence, as embracing a minute
and accurate account of all the known examples of the phae-
nomenon, its causes, its uses, and a yet more critical inquiry
into the chemical nature of the phosphorescent process than
it has hitherto received, is still open to investigation. And
lest any should be inclined to underrate this humble yet in-
teresting department of inquiry, I would venture, in reference
to it, to bring to their recollection the high authority of Bacon,
who says, " And here men ought to lower their contemplations
a little, and inquire into the properties common to all lucid
bodies ; as this relates to the form of light ; how immensely
soever the bodies concerned may differ in dignity, as the sun
does from rotten wood, or putrefied fish*."

Weston-super-Mare, Sept. 8, 1849.

* On the Doctrine of the Human Soul, p. 113. vol. i.. Bacon's Philoso-
phical Works.

[ 422 ]

LI. Oti the Vibratory Movements which Magnetic and Non-
magnetic Bodies experience under the influence of' external
and transmitted Electric Currents, By Professor De la
Rive*.

MWERTHEIM has published in the Annates de
• Chimie et de Physique, 3rd series, vol. xxiii. p. 302,
some further researches on the sounds produced by the electric
current. He directs attention to the fact that these sounds
are of two kinds ; those proceeding from the action of an ex-
ternal current which magnetizes an iron bar or wire, and
those produced by a current transmitted either through an iron
bar or wire. The sounds of the first kind were discovered as
early as 1837 by Mr. Page, and afterwards investigated by MM.
Marian, Matteucci, Wartmannf and myself I was the first who
indicated the existence of the sounds of the second kind, which
Mr. Beatson discovered nearly at the same time as myself, and
which have also been the object of the researches of the physi-
cists named above, and likewise of some others. M.Wertheim,
in 1844, demonstrated that the electric current and magnetiza-
tion produce a diminution of the coefficient of elasticity (m the
bodies which are submitted to their influence ; but he thought
that he perceived in the sounds produced by these two causes
rather a mechanical effect than a molecular phaenomenon J,
attributing the sounds which the magnetization determines to
the attractive action of the helix on the wire or on the bar of
iron, and those caused by the transmitted current to a kind
of shock which that transmission effected upon the conducting
metal. Admitting, in the case of magnetization, in part the
cause pointed out by M. Wertheim, I showed that the mole-
cular action has its own, and that, in the case of the trans-
mitted current, it alone is active. An experiment by M.Guiller-
min, and the researches of M. Wartmann, confirmed this view,
if not on all points, at least on the greatest number. Lastly, in
a more recent memoir, I succeeded in showing that, under the
influence of a magnet or a helix traversed by a continuous
current, all conducting bodies are capable of producing a
sound when they transmit a discontinuous current.

Li a memoir just published, M. Wertheim, resuming the
subject, establishes first, by numerous experiments made with
great care, that in magnetization there is a mechanical trac-
tion due to a longitudinal and to a transversal component;
that the latter becomes null when the iron bar is in the centre

* From die Annates de Chimie et de Physique for June 1849.

t Phil. Mag. vol. xxviii. p. 544.

X Comptes Rendus des Seances det'Academie des Sciences, vol. xxiii. p. 336.

On the Sounds produced hy the Electric Current. 423

of the helix, but that in all cases the longitudinal one sub-
sists; and that this force, acting in the direction of the axis,
exists equally with a transmitted current. It must produce a
longitudinal sound, whether it tends to lengthen or abruptly
to shorten the bar ; the transversal sound can only arise from
the external current, and in an excentric position of the bar.
Passing then to the examination of the sounds themselves,
M, Wertheim finds their explanation in the mechanical ac-
tions which we have just indicated; he does not therefore
think that either the magnetization or the transmission of the
electric current produces vibrations of a particular kind; but
he supposes that the mechanical actions which they engender
determine accidentally these longitudinal or transversal vibra-
tions, as any other cause might do. He admits, however,
that there is in some cases a dull noise {bruit sec), like a kind
of crepitation, which is propagated at the moment when the
current traverses an iron bar or wire ; and he concludes by
remarking, that there are still in this class of phaenomena
many obscure points, especially that which relates to the
manner in which a current traversing the iron produces in it
a mechanical shock.

M. Wertheim's new observations, of which I have thus
given a summary, have induced me to resume my experiments,
and to investigate more closely the curious phasnomena in
question.

It appears to me evident now, that the point which I have
sought to establish in my first memoir of 1845*, namely that
the magnetization or the passage of the electric current pro-
duces a molecular derangement, is no longer disputed. I
admit, on the other hand, that I have perhaps attached too
much importance to the nature of the sounds produced, and
to the influence of certain causes, such as tension, which oc-
casions them to vary. It may be, in fact, that the wire, once
set in vibration by either the external or transmitted cur-
rent, a simple friction against any metallic piece next to the
monochord may suffice, if not completely, at least in many
cases, to account for the variety of the remarkable sounds
which are heard, especially when well-annealed iron wires are
usedt.

My attention has therefore been especially directed, in

* Coviptes Rendus des Stances de I' Academic des Sciences, vol. xx. p. 1287j
and Archives de rElectricite, vol. v. p. 200.

^ The Coviptes Rendus de V Academic des Sciences, vol. xxvii. p. 457,
contains tiie extract of a memoir by M. Duhamel on the multiple sounds
of bodies, which it appears to me may be well applied to the study of the
sounds produced in the iron wires by simple molecular movements. See
Phil. Mag., vol. xxxiv. p. 415.

42i Prof. De la Rive on the Vibrator^/ Mmements

the researches which I have just made, to the investigation
of the cause of the fundamental fact, that is to say, of the
oscillations which the particles of bodies experience around
their position of equilibrium by the action of either external
or transmitted currents. With this view, I first submitted to
experiment bodies, like iron, susceptible of magnetism, and
then other conducting bodies which are not magnetic.

§ I. Examination of the Vibrations produced in magnetic bodies
by either external or transmitted currents.

On placing very fine iron-filings in the interior of a helix
with the axis vertical, these filings are seen to form themselves,
under the influence of the current traversing the helix, into
small pyramids, elongated in the direction of the axis, which
are destroyed and re-formed rapidly when the current is in-
termittent. The action of the current of the helix on these
filings consists, therefore, in distributing them under the form
of an elongated thread parallel to the axis, — a thread which
the weight alone prevents being as long as the helix itself.

This experiment, which I have ali^eady described, and which
succeeds as well with very fine iron powder as with iron-
filings, proves that the particles of iron under the influence of
external magnetization tend to approach each other in the
transversal direction, and to extend in the longitudinal direc-
tion. It is probable that this phaenomenon is due to the form
of the elementary particles of the iron, and to the manner in
which they are polarized. One thing is certain, that it ac-
counts for what passes in an iron bar or wire submitted to the
influence of the intermittent current of the helix. The particles
of the iron contending with the cohesion arranjje themselves
In the longitudinal direction when the current acts, and return
to their primitive position as soon as it ceases; from this re-
sults a series of oscillations which are isochronous with the
interruptions of the current. This manner of viewing the
phaenomenon entirely agrees with the contraction in the trans-
versal direction accompanied by an extension in the longitu-
dinal direction, which Mr. Joule observed in iron wires and
bars submitted to magnetization*.

The same physicist has also remarked that when the wire
is much stretched, the magnetization occasions a shortening
instead of a lengthening, — an effect which agrees with the
cessation of the sounds I have observed when the tension
becomes too strong.

Ail these effects are much more decided in soft iron than

* Phil. Mag. Feb. 1847 and April 1847.

of Magnetic mid Non-jnagnetic Bodies. 425

in hardened iron and steel ; the cause of which is, that in soft
iron the particles are much more mobile around their position
of equilibrium. Soft iron and steel magnetized by the action
of a magnet or a second helix, exhibit weaker vibrations when
the external current tends to magnetize them in the direction
in which they are already magnetized, and stronger in the con-
trary case. The passage of a continuous current through an iron
wire modifies the sound which the intermittent action of the
external current of the helix causes it to emit, provided that
the transmitted current is very strong and the iron very soft.

I shall not enlarge more on this first case, which 1 think is
now well explained ; I pass to that of the transmitted current.

An electric current transmitted intermittently through
a wire of very soft iron and of small diameter (of 1 to 3
millimetres), determines in it vibrations as strong as those
which are produced in it by the same current acting extei'-
nally under the most favourable conditions. If the iron wire
becomes larger, or if it is more hardened, or if it is a steel
wire, the effect of the transmitted current is less than that of
the external current*. With rods of soft iron, of 4 to 5
millimetres in diameter, the transmission of the continuous
current does not completely extinguish, but only diminishes,
the effect of the discontinuous current. If the rods are very
large, the diminution becomes less perceptible, unless very
strong batteries are employed. In the preceding experiments,

1 made use of two of Grove's batteries of five cells, one for
the continuous current, the other for the discontinuous one.

The same experiment made on steel rods and wires gave
me precisely contrary results. The sound produced by the
transmission of the discontinuous current is weak ; but it is
increased, instead of being diminished, by the passage of a
continuous current passing in the same direction as the dis-
continuous one. It is a curious fact, that this augmentation
remains some instants after the continuous current has ceased
to pass ; and that it disappears, not all at once, but by degrees
and by fits.

I performed these experiments with steel wires of 1 and

2 millimetres in diameter, with rods, both tempered and not
tempered, of 3 to 4 millimetres in diameter. The results
were the same; the strengthening due to the continuous cur-
rent is more decided with the rods than with the wires f.

* This experiment of the iron wire covered with silk its whole length,
and which gives all the same sounds as when its surface is perfectly naked,
would seem to indicate that external causes, such as friction, enter less
than is imagined into the production of these sounds: this point deserves
to be more closely examined.

f The steel rods are magnetized by the simple passage of these disconti.

426 Prof. De la Rive on the Vibratory Movements

It seems to me to result from what precedes, that the effect
of the transmitted current is to give to the molecules of the
iron a transversal direction, as the effect of the magnetization
"WSLS to give them a longitudinal one. If the arrangement of
the particles of the iron-filings around an iron or any other
metallic wire, traversed by an electric current, be examined
with attention, these filings are seen to arrange themselves
in parallel transversal lines. This is very evident on fixing
the conducting wire into a groove made in a wooden board.
The filings, being unable to go round the wire, assume a
transverse position above it, forming small threads of 3 to 4
millimetres in length, which present opposite poles at their two
extremities. When the wire is free, these threads, instead of
remaining rectilinear, unite at their two ends, and envelope
the surface of the wire, forming around it a closed curve.
Now the arrangement which the iron-filings assume around
any conducting wire transmitting a current, should be equally
assumed by the molecules of the surface of a soft iron wire
itself traversed by a current, owing to the effect of this cur-
rent transmitted through the whole mass of the wire. This
is moreover proved by the experiments of Mr. Joule, which
show that a soft iron wire or rod experiences a shortening from
the effect of a transmitted current. It results, therefore, that
when the transmitted current is intermittent, the particles of
the surface oscillate between that transversal position and their
natural one, and that consequently there is a production of
vibrations. These oscillations are the more easy, and conse-
quently the vibrations are the stronger, in proportion to the
softness of the iron ; with hardened iron, and especially with
hard steel, there is a greater resistance to overcome, and the
effect is consequently less perceptible. In the first case, the
transmission of a continuous current, by impressing on the
particles in a permanent manner the position which the dis-
continuous current tends to give them, must annul or at least
materially diminish the oscillatory movement ; this in fact takes
place. In the case of the hardened iron or steel, the conti-
nuous current must, on the contrary, by disturbing the par-
ticles from the normal position, without however being able
completely to impress on them the transversal direction, on
account of the too great resistance which they offer to a dis-
placement, facilitate the oscillatory action of the discontinuous

nuous currents without external current ; but they acquire numerous poles.
Is this magnetization attributable to the effect of the terrestrial magnetism
which the molecular vibrations experienced b)' the steel would favour, or
is it a direct effect of the current transmitted intermittently? New re-
searches would be necessary to solve this question.

of Magnetic and Non-magnetic Bodies. 4<27

current ; experiment confirms this. With regard to the in-
terruptions in the intensity of the sound in this last case, after
the continuous current has ceased to pass, they are probably
attributable to the fact that the particles, disturbed from their
natural position for a longer or shorter time, only return after
a more or less prolonged series of oscillations, which the un-
interrupted action of the discontinuous current favours.

In aid of the explanation which I have just given, I will
add that, having covered a copper wire with an iron en-
velope which was contiguous to it, and, so to say, plated, I
obtained, by passing the discontinuous current through the
copper wire, the same effects, excepting intensity, as if the
wire had been entirely of iron ; only the sound was not mu-
sical, but resembled that which would have been emitted by
filings strongly agitated. As this result might be attri-
buted to the fact that a part of the current traversed the
iron covering itself, instead of circulating exclusively through
the copper wire, I isolated this last by means of a layer of silk
or wax, so that the thin cylinder of sheet-iron which sur-
rounded it was not in metallic communication with the copper.
The effect was exactly the same as in the preceding case ;
that is to say, the copper wire being traversed by a disconti-
nuous current, caused a series of vibrations, or dry and me-
tallic sounds, in the iron covering. This covering underwent,
therefore, a transversal magnetization analogous to that which
the surface of a wire entirely of iron experiences ; this, indeed,
was easily proved from the fact, that the iron-filings were at-
tracted on the two sides of a small longitudinal slit which this
covering presented in some parts of its surface, and that the
two margins possessed an opposite magnetic polarity. All these
effects were more marked when a continuous current, going
in the same direction as the discontinuous one, was transmitted
through the copper wire ; they ceased entirely as soon as the
two currents no longer passed. This increase in intensity of
the sound produced by the passage of the continuous current
was due to the fact that the discontinuous current had not
alone, from acting at a distance, power enough to surmount
the coercitive force of the iron covering, which itself was very
much hardened, and that it needed the aid of the continuous
current to impress a transversal position on the particles of the
iron.

Before concluding this first part of my researches, I must
again observe, that the passage of a continuous current, passing
in a contrary direction to the discontinuous one, diminishes
the sound instead of destroying it completely, when the wire
submitted to the experiment is of soft iron ; it modifies without

428 Prof. De la Rive on the Vibratory Movements

perceptibly weakening it in the steel wires and rods ; lastly, it
causes it completely to disappear in the iron tube through
which the conducting copper wire covered with silk passes.
These effects vary, moreover, with the absolute intensity of
the currents employed j and they are easily interpreted on the
principles which we have stated. We must, moreover, not
lose sight of the fact, that when the continuous and discon-
tinuous currents are of equal force, they destroy one another
whenever they pass together; so that the discontinuous one
no longer acts, and the continuous one becomes intermittent
in its action.

Lastly, permanent magnetization materially modifies the
sound which the passage of the discontinuous current causes
a soft iron wire or rod to emit. In order to guard, in this
experiment, against the mechanical effects due to magnetiza-
tion, I placed a soft iron rod on the two poles of an electro-
magnet, taking care by means of an interposed sheet of paper
to avoid metallic contact between the poles and the rod.
I then placed upon it considerable weights, that its position
might not be modified by the magnetization, and passed the
discontinuous current through the rod ; it gave out a succes-
sion of dry metallic sounds, which became much more in-
tense and grave at the moment when 1 magnetized the elec-
tro-magnet. It is evident that this modification and this
strengthening of the sound are caused by the contest which is
established between the longitudinal position which the influ-
ence of the magnetization impresses on the particles of the
soft iron, and the transversal position which the passage of
the current tends to give them ; the oscillations of the particles
must necessarily have more amplitude, since they take place
between these extreme portions. The effect of permanent
magnetization, although still perceptible, is less marked with
steel rods, and especially with those of tempered steel.

§ II. Investigation of the vibratory movements 'which ?ion-mag-
netic bodies experience under the influence of external and
transmitted electric currents.

I stated in a preceding memoir, that rods, even of a tolerable
size, of different non-magnetic metals emitted a distinct sound
when, after having placed them under and very near an electro-
magnet or in the interior of the axis of a helix, a discontinuous
current was made to pass through them. The sound only be-
came perceptible, whatever was the force of the transmitted cur-
rent, at the instant when the wire of the electro-magnet or that
of the helix was traversed by a continuous current. I also ob-
served that the effect was still more marked when the metal was

of Magnetic and Non-magnetic Bodies, 429

in the form of a tube, or of a large wire turned into a helix. I
likewise convinced myself, by employing rods of large dimen-
sions, that the production of the sound could not be attributed
either to a calorific effect of the current, nor to a mechanical
action exerted by the electro-magnet or by the helix upon the
conductors traversed by the discontinuous current. I have
since made some new observations which sufficiently show
that this kind of action is of a particular nature, probably
molecular, like that which takes place in magnetic bodies.

Let us first remark, that with a single discontinuous current
the phaenomenon may be produced without having need in
addition of a continuous current or of an electro-magnet. It
suffices, for this, to twist the wire which conducts the discon-
tinuous current into the form of a helix. A magnet is thus
created ; for every time that the current traverses the helix,
the latter acquires magnetic properties, and at the same time
the wire of the helix is itself a conductor traversed by the dis-
continuous current upon which the whole of the helix con-
sidered as a magnet acts. Moreover, every helix constructed
of any metallic wire, the coils of which, whether covered or
not with silk, are more or less pressed together, emits a very
distinct sound when it is traversed by a discontinuous current.
A continuous current, transmitted in the same direction as the
discontinuous one, causes the sound to cease entirely, or di-
minishes its intensity materially, although a notable increase
results from it in the electro-magnetic intensity of the helix.
This neutralizing effisct is probably owing to the fact, that the
continuous current impressing permanently on the particles
of the wire the position which they should take under the
magnetic influence which the helix itself exerts, the disconti-
nuous current no longer causes, at the instant when it is trans-
mitted, new displacements. This effect is perfectly similar to
that which is exerted by a continuous current when it passes
through an iron wire traversed by a discontinuous current;
it causes a cessation of the sound which this wire made under
the action of the last current.

But if the continuous current, instead of traversing the wire
of the same helix which conducts the discontinuous current,
circulates through the wire of another helix which surrounds
the first, the effect is totally different. In this case the sound
is perceptibly increased, and becomes in general more metallic;
this increase is more perceptible in proportion to the weakness
of the discontinuous current, and the energy of the ambient
continuous current. In this experiment the two currents pass
in the same direction ; so that the two helices, considered as
magnets^ present each the same magnetic pole at their same

d-SO Prof. De la Rive on the Vibratory Movements

extremities. If the ambient continuous current proceeds in a
contrary direction to the discontinuous one, the sound is
weaker than in the preceding case, but stronger than when
the exterior helix does not act; it produces likewise a differ-
ent impression : it resembles the noise of water on the boil,
whereas before it seemed to resemble that which a succession
of strong sparks would have occasioned. We must remark,
however, that if the discontinuous current is powerful enough
to cause of itself a sufficiently intense sound to be easily heard
at some feet distant, the influence of an external continuous
current, when it passes in a contrary direction, diminishes the
intensity of the sound. It always increases it, and in all cases,
when the two currents pass in the same direction.

The continuous current may also be transmitted through
the internal helix, and the discontinuous one through the
external helix, contrary to what took place in the preceding
experiments. In this case, if the two currents pass in the
same direction, the sound resembles a succession of shocks;
and when they pass in a contrary direction, the noise is only
slightly increased, unless the discontinuous current is produced
by a weak battery, for example, by a couple of Grove's cells :
then the increase takes place also ; only the noise resembles
that of water on the boil.

It is easy to understand how a helix traversed by a continu-
ous currrent, and placed externally or internally to the helix
traversed by the discontinuous current, increases the sound
which this latter emits. In fact, a permanent magnet is in
this case created, the action of which is added to that of the
temporary magnet which the discontinuous current creates
when it passes through the helix. Moreover, in passing the
continuous current through the wire of another helix than that
which transmits the discontinuous one, the molecules of the
conducting wire do not at first receive the position which
they take only by the effect of the passage of the disconti-
nuous current; this it is that causes them to oscillate freely
around their natural position of equilibrium. The same re-
sult could not \)e obtained when the two currents passed
through the wire of the same helix, as we have already re-
marked.

When the currents pass in contrary directions in the two
helices, it is evident that the result is a diminution in the total
magnetism of the whole of the two helices placed in juxta-
position : this is the reason that the sound is not generally
increased ; and it is only so when the discontinuous current
being very weak, the magnetism of the helix which it traverses
is so likewise. The magnetism of the other helix, traversed

of Magnetic and No7i'magnetic Bodies. 431

by the continuous current more energetic than the disconti-
nuous one, then exerts a preponderating influence.

With respect to the difference in the nature of the sound,
according as the continuous current passes in the same direc-
tion as the discontinuous one, or in a contrary direction, I
can only explain it by admitting that the influences of the two
magnetisms, opposed and unequal in intensity, diminish the
amplitude of the oscillations which the particles of the wire
traversed by the discontinuous current make around their
natural position of equilibrium, — an amplitude which, on the
contrary, is more considerable when the two magnetisms act
in the same direction.

I placed a tube of soft iron between the two helices; an
increase in the intensity of the sound took place when the two
currents proceeded in the same direction, — a diminution and
even a complete annihilation when they went in a contrary
direction. If the soft iron tube is longer than the internal
helix, its presence completely intercepts the influence of the
external helix traversed by the continuous current : this is not
the case if the tube is slit lengthwise ; its presence then in no de-
gree modifies thephaenomena. On placing the tube, or a massive
cylinder of soft iron in the axis of the internal helix, and no
longer between the two helices, the sound is perceptibly in-
creased, especially when the continuous current traverses the
internal helix, and the discontinuous one the external helix;
the increase takes place even when there is only a discontinu-
ous current. In all cases the nature of the sound does not
change ; its intensity alone is modified.

A tube of copper or of any other metal produces no effect
when placed in the axis of the internal helix. This is not the
case if it is between the two helices ; it then causes a new
sound: this sound is evidently attributable to a current of in-
duction which circulates around the copper tube ; for if this
tube is slit in its whole length, there is no longer any sound,
even when, to increase the magnetic force of the helix, a cy-
linder of soft iron is placed in its axis.

It is not necessary that the conductors traversed by a dis-
continuous current should have the form of wires or that of a
rod, to give out a sound under the influence of a magnet or a
continuous current. A brass disc, 12 centimetres in dia-
meter and 1 millimetre in thickness, was placed horizontally
in the centre of a helix, by means of a vertical metallic support
which was fixed in the centre of the disc. Care was taken to
avoid any contact between the sides of the disc and the in-
ternal surface of the helix ; the discontinuous current was
directed from the centre to the circumference, or from the

432 Prof. De la Rive on the Vibratory Movements

circumference to the centre. As soon as a continuous current
was transmitted through the wire of the ambient helix, a well-
marked succession of metallic sounds was heard in the disc.

Even mercury can produce sounds, as I have already re-
marked. To render them perceptible, it is only requisite to
introduce the mercury into a tube a few millimetres in diameter,
and shaped so as nearly to envelope the pole of the electro-
magnet. As soon as the latter is magnetized, and the discon-
tinuous current traverses the mercury, a series of sounds is
heard similar to those which would result from a regular suc-
cession of sparks produced by a strong current between the
mercury and a metallic wire. There is not, however, any
trace of this, as may be easily ascertained ; and, moreover, a
current too feeble to produce sparks passed through the mer-
cury is capable of producing the phaenomenon. A remarkable
fact is, that if, instead of being a little below the polar surface
of the electro-magnet, the tube which contains the mercury
is upon that surface itself, the sound is not heard. All these
effects are very distinct from the movement which the mercury
acquires under the influence of magnets, when it is traversed
by either discontinuous or continuous currents.

I shall not for the present recur to the remarkable sounds
which the voltaic arc occasions under the influence of the
electro-magnet, — sounds which I have carefully described in
a previous memoir*. They are evidently of the same nature
as those of which I have just spoken ; for in the voltaic arc
the current is, so to say, intermittent from the very nature of
the arc which conducts it.

The following, therefore, is the general phaenomenon. When
any solid conductor, liquid or gaseous (at least very much
divided, as in the voltaic arc), is traversed by an electric cur-
rent,— a magnet, or an assemblage of electric currents closed,
and having consequently magnetic properties, acts upon the
particles of this conductor so as to give them a relative position
different from that which they have naturally. Hence it re-
sults that, if the transmitted current is discontinuous, the par-
ticles oscillate between their normal position and the forced
position which the magnetic influence tends to impart to them ;
this gives rise to the sounds, and explains the modifications
which it presents.

Does the action of the magnetism alone suffice to alter
the relative position of the particles of all the bodies, or is the
combined action of the magnetism and the electric currents
requisite? Faraday's experiments seem to favour the first
hypothesis; for the action exerted on light by transparent
* Phil. Mag. vol.xxxi. p. 321.

of Magnetic and Non'magnetic Bodies. -tSS

bodies subjected to the influence of a strong electro-magnet
clearly indicate a molecular derangement in them. The re-
cent researches of M. Matteucci, showing that a mechanical
action, such as compression, may annul or increase on the
same substance (heavy glass, for example) the effect obtained
by Faraday by means of an electro-magnet, confirm the fact
that this last effect is also a molecular phaenomenon.

With regard to non-transparent but conducting bodies, if
they are magnetic, they experience a molecular modification
under the action of the magnet, as we have stated above. If
they are not magnetic, they are diamagnetic ; and then it is
very probable that the diamagnetism causes a change in the
position of their particles, as magnetism does in the others;
ibr it appears to be satisfactorily proved that diamagnetism
is attributable to a transversal polarity, as magnetism is due
to a longitudinal polarity*. Now whenever any cause pro-
duces a polarity in the particles, these must, in obedience to it,
arrange themselves in a determined relative position exactly
as takes place in the phaenomenon of crystallization.

It is therefore probable that, under the influence of a mag-
net or of an external current, the particles of a diamagnetic
body tend to arrange themselves transversely; whilst under
that of a transmitted current, they take a longitudinal direc-
tion, as is shown by the force of projection which carries the
particles of a conductor from the positive to the negative pole,
at the point where the circuit is interrupted, in giving rise to
the voltaic arc. The struggle between these two contrary
tendencies, the one transversal, the other longitudinal, pro-
duces the oscillatory movements of the particles around their
position of equilibrium, and consequently the vibrations.

In the production of the currents of induction, this mole-
cular derangement which is produced by the magnetic action
of a magnet or of a closed current must necessarily take place.
To this derangement is probably due the production of an
instantaneous electric current; just as when the molecular
derangement ceases on the disappearance of the cause which
has determined it, there arises a second electric current, ha-
ving a contrary direction to the first. It is easy to understand
why these two currents pass thus in opposite directions.

A conductor placed under the influence of an electro-
magnet, or of molecular currents, must therefore be, as long
as that influence is exerted upon it, in peculiar molecular con-
ditions. This is shown by the affections of light in those which
are transparent; it remains to be demonstrated by other

* The recent researches of Prof. Faraday on the magnetic polarity of
crystals of bismuth are quite favourable to this view.

Phil. Mag. S. S. Vol. ^5. No. 238. Dec. 189. 2 F .

434 Mr. J. Cockle on Quadruple Algehra

direct means, as to those which are opake, as Mr. Joule has
done for magnetic substances. For the proofs drawn from
diamagnetism and sonorous vibrations are only indirect,
although the last appear to be tolerably conclusive.

I shall soon return to this subject, in reference to some
researches on the relation between diamagnetism and the in-
duced currents, on which I am at present engaged.

LII. On Systems of Algehi^a involving more than one Ima-
ginary; and on Equations of the Fifth Degree. By James
CockLe, Esq., M.A., Barrister-at-La'w'^.

CONCEIVE two imaginaries, such that their respective
squares are equal either to positive or to negative unity.
Then the product of two linear functions of these imaginaries
is not of the same form as its factors. The product of the
imaginaries prevents this similarity, and obstructs the forma-
tion of a System of Triple Algebra on the basis just men-
tioned. But, if we invest the last-named product with the
character of a third imaginary, and assume that its square is
equal either to positive or to negative unity, four systems of
Quadruple Algebra will present themselves, in each of which
the product of two linear functions of the three imaginaries
will, in general, have the same form as its factors.

Let « and /3 respectively represent the first and second, and
7 the third imaginary. Then y=«/3 or /3«. But as, in qua-
druple algebra, aj3 is not always equal to /3«, I shall select the
former as the expression for 7.

Let A denote a linear function of a, j6, and y; in other
language, let

A = w + «jr + /By + y2;,

then, in one of the four systems of quadruple algebra above
alluded to, the expression A bears the name of a quaternion.
In the remaining three systems the respective terms tessarine,
coquaternioji, and cotessarine may be applied to it. At least
I have suggested such a nomenclature in No. 1360 of the
Mechanics' Magazinef, where I have shown the existence of

* Communicated by the Author, In connexion with his paper published
at pp. 406-410 of the preceding (34th) volume of this Journal, Mr. Cockle is
desirous of referring the reader to two articles subsequently communicated
by him to the Mechanics' Magazine, and which will be found at pp. 634
and 558, 559 of vol. 50 of that work.

t See pp. 197, 198 of the current (51st) volume of that work. I had,
however, previously employed the term " Tessarine " both in that and in
the present Journal.

and on Equatiofis of the Fifth Degree. 435

these four systems, discussed them, and pointed out their cha-
racteristics. I here propose to advert for a moment to the
same subject, to consider it under a slightly different aspect,
and also to exhibit, for convenience of comparison, the mo-
dular expressions of all the systems. We have, then,

1. The Quaternion System of Sir W. R. Hamilton^ in
which

a2=_i, |3«=-1, and «/3 = y;

but in vk'hich also

contrary to what we should have inferred from the equations

hence, the quaternion system is abnormal, or does not obey
the laws of ordinary algebra. The modulus of a quaternion is
the positive square root of the expression

IIO^ + X^ + J/^ + Z^.

2. The Tessarine System — a normal system in which

a2=-l, /32=1, and y^=-l=u^fi^

The true modulus of the tessarine A is the positive square
root of

(M?+^)2 + (a? + 5r)2.

3. The Coquaternion System, in which

a2= — 1, /32=:1, and y^=l;
but the last relation is inconsistent with the conditions

and the coquaternion system is abnormal. The modulus of
A, considered as a coquaternion, is the positive square root of

4. The Cotessarine System, in which

«2=l^ /32=,1^ ^2^ 1^5,2^2^

and which is a normal system, having for its modular form the
positive square root of

It is to be borne in mind, that in all the above systems
y=aj3; that, whenever the double sign ( + ) occurs, the sign
of the term is indifferent and quite independent of that of the
preceding or following term ; that w, a^, y, and z are real
quantities, positive, negative, or zero ; and that, in multiplying

2 F2

436 Mr. J. Cockle on Quadruple Algebra,

two expressions of the form A, the modulus of the product is
the product of the moduli of the factors. It is for the purpose
of analogy and of making the modulus positive, in all cases,
that I have given a quadratic form to the formula employed in
expressing the cotessarine modulus.

On Equations of the Tiftli Degree.
Whether Mr. Jerrard has succeeded in pointing out a
method of solving the algebraic equation of the fifth degree
or not, his investigations at pp. 545-574 of vol. xxvi. (continued
at p. 63 of vol. xxviii.) of the present Series of this Journal
must ever be a subject of interest, and form an essential part
of the theory of such equations. There are, however, one or
two portions of his papers which seem to me involved in doubt
and difficulty — difficulty which, in one case, he has himself
adverted to and endeavoured to explain. Mr. Jerrard will
pardon me if, with great hesitation, I venture to intimate an
opinion that the position taken by him in his note [|] to p. 572
of vol. xxvi. is untenable. By way of example, suppose that
the square root of a^ + /^ is the function to be expanded. The
general form of the expansion* is, —

A Series of converging or diverging terms ^/m5 a Remainder.

Now, when the series is convergent, the remainder may, in
all cases where numerical value is the subject of inquiry, be
entirely neglected ; but it does not the less constitute an essen-
tial part of the symbolic expansion. Hence I conceive that,
in considering the expansion under a purely symbolic point of
view, even the convergent development must be regarded as
incomplete without the remainder, and so placed on the same
footing as the divergent one. Considered thus, the convergent
and divergent developments are deducible, the one from the
other, by an interchange of a? and //, and each admits of that
interchange without alteration o^ symbolic value. And I think
that we necessarily obtain an expression which admits of such
interchange — at least in all cases where a strictly symbolical
expansion is required ; and, if I rightly understand Mr. Jer-
rard's argument, it is to such expansions that his remarks
apply.

But, admitting for a moment that the convergent series with
the remainder neglected is &. symbolic expansion of the function,

• I have elsewhere (in the course of my HorcB AlgebraiccB, Mechanics'
Magazine, vol. xlvii. p. 150) suggested contraction as a term to denote the
inverse of expansion. Would it be advisable to confine the terms expan-
sion and contraction to symbolic operation, and to use the terms involution
jind evolution exclusively in reference to arithmetic or quasi-arithmetic
operations, including them both under the cominon name volution ?

Mr. E. J. Lowe on a remarJcable Solar PJKjenomenon. 437

I feel some doubt as to another portion of Mr. Jerrard's ar-
gument. At all events I think it would be very desirable to
show clearly the solvibility of the equation by which W is to
be determined. It is true that one of its roots appears to be
a known and rational function of another of them, and that an
equation among whose roots such a relation exists is supposed
to be capable of solution by means of the process of Abel.
But doubts — and doubts apparently well-founded — have arisen
respecting the universality of that theorem. It is not my
object to discuss them here ; but I would refer the reader to
the learned paper on the Calculus of Functions in the Ency-
clopedia Metropolitana^ where, at pp. 327, 328, art. (90.), and
at pp. 381, 382, arts. (302.) and (303.) of vol. ii. of the Pure
Sciences, he will find remarks upon this question ; and I
would also call attention to the respective notes to arts. (90.)
and (303.) just adverted to. There, the nature of the difficulty
which militates against the generality of the theorem — a diffi-
culty which, in the instance of functions of a degree so low as
the third, is only obviated by our having complete solution of
a cubic — is clearly exhibited.

Standing on the frontiers which separate solvible equations
from those as yet unsolved, the biquadratic partakes of the
nature of both. It resembles the one inasmuch as it is capable
of finite algebraic solution; the other, in its incapability of
finite algebraic solution in terms of irreducible biquadratic
surds. The latter characteristic might perhaps be of ser-
vice in the discussion of equations of the fifth degree, and
in the manner which I suggested in my First Series of Notes
on the Theory of Algebraic Equations, published in vol. xlvi.
of the Mechanics' Magazine. The reader is referred to p. 125
of that volume, and to the condition mentioned at a subsequent
page (180) of it.

2 Church -Yard Court, Temple,
November 1, 1849.

LTII. Remarkable Solar PJiocnomenon seen at the Villa,
Beeston near Nottingham, October 22, 1 849. By Edward
Joseph Lowe, Esq., F.Il.A.S.*

/^N the above day a strange spectacle presented itself about
^-^ the sun. The morning had been misty, and had cleared
up about 22^^; but being engaged with some papers I did
not look at the sun until 0^ 10™, when a remarkable phae-
nomenon was immediately discovered: it resembled a huge

* Cominunicated by the Author.

438 Mr. E. J. Lowe on a remarkable Solar Phcenomenon.

pair of wings, AA, 70° in length, very sensibly prismatic, the
red being next to the sun, and almost as brilliant as the smi

himself. The sun was pale and sparkling, and the phaeno-
menon brightest directly above that luminary. This was
about 25° above the sun.

Qh i3m^ The singular spectacle changed from being pris-
matic to pure txiJiite', and a circle, BB, of 50° diameter, having
the sun for its centre (also colourless), was now visible.

0^ 14°i. A mock sun, C, was apparent although faint, being
tinged with prismatic colours, and had a well-defined edge.
It was situated on the horizontal level of the true sun on the
circle of 50° in diameter, and on the preceding side of the
sun.

0"^ 15°^. Mock sun C vanished.

O'^ le*". Another mock sun, D, was faintly visible, formed
on the circle above alluded to, and on its left-hand side, at
about an altitude of 12i° above the horizontal level of the true
sun.

Qh 18"^. The appearance of wings, together with the mock
sun D, disappeared ; but an arc of a circle, E, of very large
dimensions, became apparent, which cut the former circle at
C; it was inverted with respect to the true sun, and must
have had its centre on or below the north horizon. It did
not remain long enough to take any measurements.

0^ 19™. Mock sun C again visible, but faint.

0^ 20"". C vanished ; but another mock sun had appeared
at F, about 4° below the apex of the circle BB.

Qh 21°^. F, together with BB, disappeared; but the wings
AA once more became visible, being again prismatic.

(S^ 26™. BB and C again apparent, and AA more brilliant,

Qh 27™. A mock sun, H, faintly visible, situated on the
horizontal level of the sun, and on the succeeding side of the
circle BB.

Qh 27|™. H became brilliant and prismatic, having now a
tail of 10° in length tapering otf to a point, diametrically op-

On the Colouring of Glass by Metallic Oxides. 439

posite to the true sun ; also a mock sun, G, situated 4° below
the apex of the circle, BB, on the left-hand side.

0^ 33". The winged appearance is the only portion which
now remains.

0^ 39™. AA has just vanished.

During the whole of this phaenomenon thin scud was flying
rapidly over from the south, and the sky itself appeared of a
muddy blue, owing to a thin veil of vapour (probably cirro-
stratus) being interposed between us and the clear sky. Whilst
this singular appearance lasted, a thin sprinkling of rain con-
stantly fell. The sky became overcast at 0^ 45"^ with south
wind. Brilliant aurora borealis in the evening.

Villa, Beeston near Nottingham,
October 23, 1849.

LIV, Inquiries oji some modijications in the Colouring of
Glass by Metallic Oxides. By G. Bontemps*.

IN the presence of so many illustrious philosophers to
whom the sciences are so much indebted, I must certainly
apologize for my temerity in daring to call for a few minutes
their attention to my humble observations ; but if it is true
that the greater part of the improvements in manufactures are
the consequences of new scientific applications, it will be per-
haps admitted that the observation of facts connected with
manufactures has led to many new scientific discoveries ; and
I should feel happy if I could bring before you a few elements
of new progress.

The revival of painted windows, and the manufacture of
coloured flint-glass, first in Bohemia, and afterwards in all
parts of Germany, in France and in England t» in an especial
manner directed the attention of glass manufacturers, about
fifteen years ago, to the colouring of glass by metallic oxides.
They probably tried the receipts described in the works of
Neri, Merret, Kunckel, Ferrand, Haudiquer de Blancourt, and
many others, and they must frequently have met with failure; in
that case their conclusion must have been,that the authors did
not obtain the results which they announced. But the truth is,
that they had not opei'ated under like circumstances. In all cases
those receipts had but an empirical value ; chemistry was not
yet a science; it was merely an agglomeration of facts without
any co-ordination whatever ; nor was natural philosophy better

* Communicated by the Author, having been read before the British
Association at Birmingham, Sept. 1849.
f See Phil. Mag., vol. ix. p. 456.

440 M. G. Bontemps on some modifications in

able to explain the observed phaenomena. In more modern
times, by the aid of chemical science, we have been able to
analyse the metallic oxides, and their various combinations
with acids. By analogy, glass having been considered as a
salt with simple or multiple bases, general axio7ns were ad-
mitted in the colouring of glass by metallic oxides. It is said,
for instance, that the silicates oi potash and of soda are colour-
less; the silicate of^ potash or soda and 7nanga7iese IS purple ; the
silicate of potash or soda and cobalt is bhie; the silicate of pot-
ash and deutoxide of copper is blue; the silicate of potash and
protoxide of copper is rcd\ the silicate of potash and gold is
pink^ &c. Such axioms are quite sufficient for those who
want only a superficial knowledge ; but in entering more
deeply into the investigation of the phaenomena produced by
the use of metallic oxides in glass-making, it will soon be
acknowledged how fertile is the field of observations, and how
incomplete is their explanation.

Allow me to mention some of the phaenomena produced by
a few metals; several of them will perhaps have for many
persons the charm of new facts, although these metals are
those most generally used for colouring glass.

1. Iron.

It is generally admitted that oxide of iron gives a greenish
colour to glass to the mixture of which it has been added ;
but the truth is, that this colour is produced only in peculiar
circumstances.

The manufacturers of china, porcelain and earthenware,
are well-aware that oxide of iron is the colouring material of
a fine purplish-red enamel fired in their muffle (and it is quite
clear that enamels are real glass) ; if the temperature were
raised too high, this enamel would lose its purplish tinge and
tend towards orange ; so that three colours of the spectrum
are produced by oxide of iron, even at degrees of heat which I
should call low, compared with the temperature of furnaces
for glass melting, which we shall now consider.

If into a pot containing white melted glass or flint-glass we
introduce during the blowing a small fragment of iron, it
will, from its gravity, fall to the bottom ; now, if after the
blowing, this pot is taken out of the furnace, we shall see close
to the fragment of iron partly oxidized, a portion of the glass
coloured from orange to yellow. We have also an illustration
of the j/e//oto colour produced by oxide of iron in the manu-
facture of artificial aventurine. It is known that this aventu-
rine is produced by the exposure of soft glass containing a
large proportion of the oxides of copper and iron, to a tempera-

the Colouring of Glass hy Metallic Oxides. 44<1

ture below its fusion : during this exposure the copper is re-
duced in the form of metallic crystals, and the glass being
coloured only by oxide of iron, takes a broivnish-i/ellow colour ;
and the greater the reduction of copper, the yellower is the
glass.

Proceeding now to the usual circumstances of colouring
glass by oxide of iron, we find that at a temperature not very
high, for instance in covered pots for flint-glass, oxide of iron
gives a green colour approacliing nearer to yellow than to blue.
It is generally by mixing oxide of iron with oxide of copper
(giving blue) that all the tints of green are produced. The
greenish colour of bottle-glass must also be attributed to the
oxide of iron combined with the carbonaceous matters con-
tained in the mixture. But when we melt at a high tempe-
rature, for instance in the manufacture of window-glass, we
remark that the addition of a small proportion of oxide of
iron to the mixture produces a glass of a bluish colour. It is
known also by the manufacturers of bottle-glass, that when
the glass is cooled in the pot, it becomes opake blue before
being devitrified.

We have shown by the preceding remarks that glass receives
all the colours of the spectrum from oxide of iron ; and at the
same time, it will be observed that these colours are produced
in their natural order in proportion as the temperature is in-
creased.

2. Manganese.

It is generally known that oxide of manganese gives to glass
a purple or pink colour, which property is used not only for
the production of purple glass, but especially as glass soap, for
neutralizing the light greenish colour produced by slight por-
tions of iron and carbonaceous matters existing in the materials
used in making white glass or flint-glass ; but it is very re-
markable, that the light pink colour given by oxide of man-
ganese is very apt to fade : if the glass remains too long in
the melting-furnace, and afterwards in the annealing kiln,
the purple tinge turns first to a light brownish-red, then to
yellow, and afterwards to green.

I shall mention also a remarkable fact relative to the pre-
sence of manganese in the composition of glass. White glass,
in which a small proportion of manganese has been used, is
liable to become yellow by exposure to light. Having melted
for the celebrated Augustin Fresnel the glass for the first poly-
zonal lenses he made, and for which the whitest glass was
desirable, these prismatic pieces of glass became yellow after a
short time without losing their transparency and polish of

442 M. G. Bontemps on some modifications in

surface. I rightly attributed this colour to the presence of
manganese ; and, indeed, by suppressing the oxide of man-
ganese in the mixture, this effect no longer took place. Besides,
to prove that light had produced this colour, I took a pris-
matic ring recently made of glass containing manganese : I
broke it into two pieces, one of which, exposed to light during
a few weeks, became yellow ; and the other, kept shut up in a
drawer, was not at all altered in its whiteness.

It is also known that some window-panes, especially the
Bohemian window-glass, take a light purple colour after having
been a long time under the influence of light. The same
effect is produced in window-glass or flint-glass containing a
small proportion of manganese, when they remain in the flat-
tening or annealing kilns long enough to produce incipient
devitrification ; in this case the interior of the glass becomes
opake white, whilst the outside takes a pink tint.

I admit that some of the facts of colouring which I have
mentioned might be explained by reference to various degrees
of oxidation, and that manganese, for instance, loses part of its
oxygen when the glass passes from a purple to a yellow colour ;
but I doubt if this is sufficient to explain the phaenomena
which I shall call 'photogenic^ which take place when the glass
is in a solid state.

3. Copper.

Copper in its highest state of oxidation gives to glass quite
free from iron a sky-hlue colour, inclining more to green than
to purple, and in its lowest state of oxidation imparts a ruby
colour. In all times, as at the present day, red window-glass
has always been coloured by protoxide of copper; but it is
not very easy to obtain this colour, because it is not at all
fixed ; it must be seized at its proper time ; and this produc-
tion is the origin of a great many interesting and curious ob-
servations. When the red glass is in the proper state to be
blown, if it is ladled into water so as to effect a sudden cool-
ing, this \iVOi\nces yello'w-gree7i cullet; if this yellowish cullet
is heated to the point of liquefaction and cooled slowly, the
red colour will gradually show itself as the glass cools,
becoming of the finest ruby, inclining more to orange than to
purple : in some cases this colour is so delicate, that the cool-
ing resulting from the usual process of manufacture prevents
the manifestation of the red colour, and it is necessary to ex-
pose the manufactured piece of glass to the temperature of the
annealing kiln, in which case the red colour is seen to increase
gradually till it arrives at its greatest intensity : if the tempe-
rature of this kiln is too high, or if the ruby glass already

the Colouring of Glass hy Metallic Oxides. 443

made is placed in a muffle too mucli fired, the bright orange-
red colour turns first to crimson-red^ then to purple; by a
greater heat it takes a bluish tinge, and afterwards gets dis-
coloured ; it is therefore acknowledged that ruby glass must
be exposed to the lowest temperature possible to obtain the
brightest tints. From these observations we conclude that
glass in which copper is kept in the state of protoxide by
addition of tin or carbonaceous matters, is apt to acquire suc-
cessively all the colours of the spectrum, under circumstances
which do not appear to be the effect of modification by oxygen.

4. Silver.

Oxide of silver is seldom added to the mixtures which are
to be melted in glass furnaces, but is generally used to stain
glass of a transparent yellow, on the surface of which it is laid
and fired. This colour is produced without any addition of
fuM ; it is only necessary to lay on the surface of the glass or
flint-glass a small proportion of oxide, or any salt of silver in
a great state of division, mixed with a neutral medium, such
as pounded clay or red oxide of iron, and to expose this glass
to the heat of a muffle; the medium is afterwards taken off by
brushing the surface of the glass, and the glass is stained of a
yellow colour, which varies between lemon or greenish-yelloiio
and dark orange, according to the quantity of silver, and
especially to the quality of the glass ; a red colour can even be
produced by exposing the glass twice to the heat of the muffle.
The celebrated Dumas has found by accurate analysis, that
the glass which was liable to take the deep tints had its ele-
ments the nearest in definite proportions ; which agrees with
this observation, that the glass must have been deprived of all
excess of alkali by a long melting at a high temperature, to
take the deep tints of orange and red.

It is important not to heat the muffle to too high a tempe-
rature, otherwise the surface of the glass on which the silver
has been laid becomes opalescent, although when seen through
it still remains yellow or orange: the glass viewed obliquely
reflects an opake blue colour, and at a still higher temperature
it is liable to appear of a pink colour when seen through,
although the opacity of the surface is still increased, and
becomes brownish-yellow.

If, instead of staining the glass in a muffle, silver added to
a mixture of flint-glass is melted in covered pots in the short-
est time possible, the result is an agatized semi-opake matter,
which, by the combined effects of refraction and reflexion, will
present all the colours of the spectnwi ; this effect is most sen-
sible, if the surface of the glass, which is generally yellowish-

44'4< M. G. Bontemps on some modifications in

green opake, is cut to different depths. These effects are
produced by inequalities of cooling, as we have seen for man-
ganese and copper.

5. Gold.

Oxide of gold gives to the glass a pink tint, which by an
increase of quantity may attain a 'purplish-red. For this pur-
pose a small proportion of precipitated purple of Cassius is
added to the mixture of flint-glass ; but by the first melting
this mixture gives only a colourless transparent glass, which
must be heated again to show the pink colour. If, for instance,
a small solid cylinder has been formed with this first melted
glass, when cold it is quite white; but if this cylinder is
afterwards exposed to the heat of the working-hole of the fur-
nace, we see it acquire the red colour gradually as it is pene-
trated by heat ; and this colour remains fixed wlien the cylin-
der is gradually cooled again in the annealing kiln.

I have remarked also, that by varying the degrees of heating
apiece of this glass of some length at a high temperature, and
re-cooling it several times, a great number of tints, varying
from blue to pink, red, opake yellow and green, may be pro-
duced. But I am not certain that this effect might not be
attributed to some fractions of silver mixed with the gold used;
and the only point that remains quite positive, is the fact of
the pink colour showing itself by a second Jiring in the glass
into the composition of which gold enters.

To these results of colouring by metallic oxides, I shall add
an effect produced in the colouring of glass by charcoal, which
effect is of the same nature as those mentioned in the colour-
ing by copper and gold.

An excess of charcoal in the mixture of a silico-alkaline
glass gives a yellow colour, which is not so bright as the yel-
low from silver, but good enough to be used in church win-
dows ; and sometimes, according to the nature of the wood
from which the charcoal has been made and the time at which
it has been cut, this yellow colour may be turned to dark red by
a second Jire.

I doubt, indeed, whether all the results which I have men-
tioned can be explained only by various degrees of oxidation
of the metals. This multiplicity of colours, greater than the
number of oxides described for each metal, must lead us to
consider whether those pha^nomena are not the consequence of
■physical laws. It is the peculiar character of our time, and the
result of the immense progress accomplished in chemistry and
natural philosophy, to bring their study to some united views,
which render the connexion of these two sciences indissoluble.

the Colouring of Glass hy Metallic Oxides. 4-4. 5

The various facts observed in the colouring of glass, which
are especially produced by the influence of different tempera-
tures, are probably to be attributed to some modifications in
the disposition of the composing particles', which effects occasion
modifications in the reflexion and refraction of the rays of
light : indeed it might be remarked, that parts of the results
which I have meniionec] are produced tmder some circumstances
which appear to place the glass in a condition of crystallization.

In the last century, Edward Hussy Delaval, starting from
the experiments made by the immortal Newton in the colouring
of thin plates, instituted some researches into the causes of the
modifications of colours in bodies; but he found chemical
science not in a state sufficiently advanced to establish his
observations on rational experiments. But at the present
lime we have only to collect a sufficient number of precise
facts to be able to deduce from them the scientific explana-
tions, which might probably lead to some new improvements
in manufactures.

As for glass, the observations relating to the constitution of
its particles are extremely delicate. This is proved by the
difference of the action of light on it, according to the degree of
annealing. It is known that even a very slight pressure, acting
on a point of its surface, is sufficient to produce the doubly re-
fracting power, which is also given by incomplete annealing;
and this effect takes place, not only when the glass, having
been quickly cooled from a red heat to the ordinary tempera-
ture, is liable to break by itself, but even in pieces of glass of
some thickness, which might be considered to be well annealed,
and which would really be sufficiently annealed for common
use : it is a fact, that the greatest part of such a glass shows
sensibly the phaenomena of polarization. This fact has still
increased the difficulties, which were already very great, in
manufacturing glass for optical purposes. The difficulty,
which is not a small one for discs of three or four inches in
diameter, is of course greater for discs often and twelve inches ;
we have however surmounted it at Messrs. Chance's glass
works for discs up to twenty-four inches : but before working
such discs, or larger ones, we think that it would be desirable
that practical opticians should throw sufficient light on the
various parts of the processes which are used in the construc-
tion of achromatic telescopes; because we could not warrant
that the glass which we consider to be free from defects, may
not, with very high magnifying powers, give evidence of new
imperfections which we have not yet suspected.

I have laid before you practical facts. If they be found
interesting enough to form the basis of new studies on the

4!4!6 M. A. De la Rive on the Cause of Aurorce Boreales.

modification of the atomic constitution of glass, I shall be
content to have brought the subject before the British Asso-
ciation : if these observations, on the contrary, are considered
not worthy of the importance I attach to them, I shall have
my excuse in the love of an art to which I have all my life
been zealously devoted. ,

LV. On the Cause of Aurorae Boreales. By Auguste de
LA Rive, being an Extract from a Letter to M. Regnault*.

I HAVE just read, in a memoir by M. Morlet on the
Auroras Boreales, inserted in the Annates de Chiniie et de
Physique, 3rd series, vol. xxvii. the following passage : —

*' With regard to the origin of this luminous matter (that
of the aurora borealis), it seems natural to attribute it to the
electric fluid contained in the atmosphere, and which, at great
heights where the air is rarefied, must become luminous as
under the receiver of the air-pump and in the barometric
vacuum : this hypothesis would acquire a great probability if
we succeeded in proving, by direct experiments, that mag-
netism exerts an influence on electric light."

This last expression induces me to request you to have the
goodness to communicate to the Academy of Sciences an ex-
periment which I mentioned to you on my passage through
Paris last June, and which you may perhaps remember ; its
object was to show, in support of the theory which I had ad-
vanced of the aurora borealis, the influence exerted by mag-
netism upon the light which is produced in ordinary elec-
tric discharges. Hitherto this influence has only been shown
in the case of the luminous arc which escapes between two
conducting points, each communicating with one of the poles
of a voltaic battery; which is very different, both as con-
cerns the phaenomenon itself, and in what concerns its ap-
plication to the theory of the aurora borealis. The following
is my experiment.

I introduce into a glass globe about SO centimetres in dia-
meter, by one of the two tubulures with which it is furnished,
a cylindrical iron bar, of such length that one of its extremities
reaches nearly to the centre of the globe, whilst the other
extends from 3 to 4 centimetres out of the tubulure. The
bar is hermetically sealed in the tubulure, and covered through-
out its length, except at its two ends, with an isolating and
thick layer of wax. A copper ring surrounds the bar above
the isolating layer in its internal part the nearest to the side

* From the Comptes Rendus for Oct. 15, 1849.

M. A. De la Rive on the Cause of Aurora Boreales, 447

of the globe; from this ring proceeds a conducting rod, which,
carefully isolated, traverses the same tubnlure as the iron bar,
but without communicating with it, and terminates externally
in a knob or hook. When by means of a stop-cock adjusted
to the second tubulure of the globe, the air in it is rarefied up
to 3 to 5 milHmetres, the hook is made to communicate with
one of the conductors of an electric machine, and the external
extremity of the iron bar with the other, so that the two elec-
tricities unite in the interior of the globe, forming between the
internal extremity of the iron bar and the copper ring which
is at its base, a more or less regular fascicle of light. But if
the external extremity of the iron bar is placed in contact with
one of the poles of a strong electro-magnet, taking good care
to preserve the isolation, the electric light takes a very different
aspect. Instead of issuing, as before, from the different points
of the surface of the terminal part of the iron bar, it is emitted
only from the points which form the contour of this part, so
as to constitute a continuous luminous ring. This is not all :
this ring, and the luminous jets which emanate from it, have a
continuous movement of rotation around the magnetized bar;
one while in one direction, at other times in another, according
to the electric discharges and the direction of the magnetiza-
tion. Lastly, more brilliant jets appear to issue from this
luminous circumference without being confounded with those
which terminate on the ring, and form the fascicle. As soon
as the magnetization ceases, the luminous phsenomenon be-
comes again what it was previously, and what it is generally in
the experiment known by the name of the electrical egg. Not
having any powerful machine at my disposal, I used for my
experiment an Armstrong's hydro-electric machine, the boiler
of which I made to communicate with the copper ring, and
the isolated conductor which receives the vapour with the iron
bar, or vice versa when I wished to change the direction of
the discharges. The experiment succeeded very well in this
manner.

The experiment which I have just described appears to me
to account very satisfactorily for what passes in the phaeno-
menon of the aurora borealis: in fact, the light which results
from the union of the two electricities in the part of the atmo-
sphere which covers the polar regions, instead of remaining
vaguely distributed, is carried by the action of the terrestrial
magnetism round the magnetic pole of the globe, whence it
seems to rise in a revolving column, of which it is the base.
We thus understand why the magnetic pole is always the
apparent centre whence issues the light constituting the aurora
borealis, or toward which it appears to converge. I shall not

448 M. A. De la Rive oji the Cause of Aurora Boreales.

recur to the other circumstances which accompany this me-
teorological phaenomenon, the agreementof which I have shown
with the explanation I have given in a letter addressed to M.
Arago, which was communicated to the Academy, and inserted
in the Philosophical Magazine for April 1849, p. 286. .g

But, having referred to this letter, in which the question
was also raised respecting the explanation of the diurnal varia-
tions of the magnetic needle, permit me to add, that 1 have
had occasion to prove, in England, both by my own observa-
tions, and still better by the more extensive ones of several
physicists*, the existence of electric currents having a direction
from the north-west to the south-east on the surface of the
earth. The presence of these currents can be easily proved
by means of the metallic wires which serve as telegraphic com-
munications : wires which are placed underground and at the
same time well-isolated, except at their two extremities which
dip into the ground, are best suited for this kind of observa-
tions. It is very curious to follow the agreement which exists
between the variations of intensity of these currents and the
variations of magnitude of the deviation of the magnetic needle
of declination ; a new proof to add to that drawn from their
direction, that they are the cause of the diurnal variations.

Colonel Sabine has stated, in opposition to my explanation
of the diurnal variations, an objection drawn from the obser-
vation of these variations at the Island of St. Helena and at
the Cape of Good Hope f. I do not think it well-founded,
and, without entering into the details which will better find
a place elsewhere, I shall limit myself to one single remark.
I attribute the origin of the currents which give rise to the
aurora borealis and to the diurnal variations, to the rupture
of the electric equilibrium occasioned, in each atmospheric
column, by the difference of temperature which exists between
its base which reposes on the surface of the globe and its upper
part which is at the limit of the atmosphere. Each column
thus forms a kind of pile charged at its two extremities with
contrary electricities, which unite in part by the pile itself, in
part by a circuit formed of the upper regions of the atmo-
sphere, of the atmospheric polar regions, and of the surface
of the earth. Meteorological circumstances determine the
greater or less proportion of the two electricities which unite
by one or other of these ways.

Now, the temperature of the base of the column must vary

* See the observations of Mr. W. H. Barlow on this subject, Phil. Mag.
vol. xxxiv. p. 344.
t Phil. Mag. vol. xxxiv. p. 4G6.

M. A. De la Rive on the Cause of Aurora Boreales. 449

not only with the season, with the time of the clay, and witli
the latitude of the place where it is observed, but also with
the nature of the surface of the globe on which it reposes.
When, therefore, this surface is the sea, the hours of maxima
and minima of temperature are not the same as when it is terra
Jirma, all other circumstances behig the same ; it results
necessarily that the hours of maxima and minima of inten-
sity of the electric currents, and consequently of the diurnal
variations to which they give rise, must be equally different.
Now, St. Helena and the Cape of Good Hope may be con-
sidered as places enveloped in atmospheric columns, which
have almost their entire base resting on the sea and not on the
land ; thence the anomalies pointed out by Colonel Sabine
are very easily explained, and, in particular, it is easily under-
stood how there is no agreement, in direction, which must in
every case be different, between the diurnal variations ob-
served at the Cape of Good Hope and those observed at Al-
giers, which is equally distant from the equator, but to the
north. An excellent paper by M. Aime on terrestrial mag-
netism, inserted in the Annales de Chimie et de Physique, 3rd
series, vol. xvii., in which he discusses comparatively the
observations made at St. Helena, the Cape, and Algiers, has
singularly facilitated the explanation of the anomalies pre-
sented as objections by Mr. Sabine.

I, however, do not pretend that there does not exist any
anomaly ; my explanation is not more free than others from
those which result from certain local and exceptional causes.
I am not further from admitting that the currents of induc-
tion determined on the surface itself of the globe, by its rota-
tion under the influence of its magnetic poles, cannot have
any part in the phaenomenon of the diurnal variations and
auroras boreales, and account for the connexion which these
variations appear to have with the absolute direction both in
declination and in inclination of the magnetic needle, and with
the absolute intensity of the terrestrial magnetism. But this
subject would require, for elucidation, to be treated more at
length than can be done in a letter; I shall therefore stop,
and beg to refer those persons who may be interested in this
question to a memoir which I am on the point of completing,
and which will be published forthwith.

Phil, Mag, S. 3. Vol. 35. No. 238. Dec, 1849. 2 G

[ 450 ]

LVI. Descriptions mid Analyses of several Americaji Mine-
rals. By B. SiLLiMAN, Jun.t M.D.^ Professor of Che-
mistry applied to the Arts in Yale College^ and of Medical
Chemistry and Toxicology in Louisville Universityy Ken-
tucky^.

nPHE results embodied in this article have been lately ob-
tained in the Analytical Laboratory of Yale College by
myself, or by my pupils under my immediate supervision and
direction.

The researches upon the new and interesting species which
belong to the family of micas is not complete ; but as many
months must pass before I can again take up this investiga-
tion, it is deemed best to present the results already obtained,
that the attention of mineralogists may be directed to them.
I will present in a second memoir such further results as may
be determined by the analyses which will be carried forward
this winter on the same species. Enough has been done, it is
believed, to give definiteness and importance to the subject.

I. Species of the Family Mica.

This series of minerals, forming a new and very interesting
addition to the mica family, is found associated with the corun-
dum of Pennsylvania; and one or more of the species are
probably associated with corundum in every locality where
the latter is found. My attention was first called to these mine-
rals by receiving from Dr. J, L. Smith, now in Constantinople,
a small portion of a similar mineral, which he has called
Emerylite. The quantity of this mineral received (only
0"2 grm.) was too small to enable me to obtain more than
its general characters. As this mica was the means of calling
my attention to the others, I will repeat the results of Dr.
Smith, with such additional characters as were obtained here.

Emerylite.

This mineral is found associated with the emery from the
localities of Asia Minor. It is in brilliant micaceous scales,
brittle and inelastic. Colour, gray with a tinge of lilac;
laminae easily separable; hardness, 3 to 3*25; gravity not
satisfactorily determined on so small a quantity. Before the
blowpipe alone in forceps, exfoliates, whitens and emits a very
brilliant light, but does not fuse. In close tube, yields water,
which gave a feeble reaction for fluorine. Dissolves in borax
to a clear glass, and leaves a siliceous skeleton in salt of phos-

• From Silliman's Journal for November 1849.

Prof. B. Siiliman on some American Minerals. 452

phorus. The reactions for silica, alumina, lime, iron and pot-
ash are satisfactory. It is not acted on by strong acids ; even
by long-continued Jboiling with Nordhausen sulphuric acid,
very imperfect decomposition was eifected.

Fused with carbonate of baryta, a qualitative analysis gave
reactions for silica, alumina, peroxide of iron, lime and potash,
with a trace of soda.

I was unable, however, with the most exact care, to con-
firm Dr. Smith's observation of the existence of zirconia —
probably a larger portion of the mineral might give a different
result.

Dr. Smith gives the following as an approximate result of
the constitution of the emerylite from several analyses made
by himself: —

Silica 30-0

Alumina 50*0

Zirconia 4*0

Lime ISO

Oxide of iron, manganese and potash . 3*0

100-0

- This analysis gives the ratio 4810^, eAlt)^, 3RO=3RO,
Si03+3(Aft)3jZW)2Si03, which gives the following re-
sult:—

4 atoms Silica . . 2309-24 = 31-93 per cent.
6 ... Alumina . 3854-00 53-30
3 ... Lime . . 1068-06 14-77

7231-30 100-00

As however the mineral contains water and the analysis is
confessedly only approximate, this formula cannot be regarded
as entirely correct ; but it will be found useful in connexion
with the results which follow.

The mineral which most closely approaches Smith's eme-
rylite, as far as our observations authorize us to form an opi-
nion, is the next in order, and marked in our analyses " A."

A. This mineral is from Village Green, in the town of
Aston, Chester County, Pennsylvania, and was sent to me by
Mr. L. White Williams of West Chester, to whom mineralo-
gists are much indebted for bringing to light many interesting
things. It is associated with corundum, and occurs in con-
siderable masses; and so much resembling common mica, as
to have escaped notice until Dr. Smith's observations on
emerylite called my attention to the minerals associated with
the American corundums. Form, like mica, apparently hexa-

2 G2

452 Prof. B. SilUman oti some American Minerals,

gonal ; folias easily separable, but inelastic and brittle. Co-
lour white ; transparent in thin foliae. Lustre, silvery,
vitreous and pearly. Hardness, 3-5. Gravity, 2995. B. B.
in forceps, exfoliates and emits a strong light; fuses on the
edges of thin laminae. In the close tube it yields water, and
gives very feeble traces of fluorine. It behaved with the fluxes
like the Turkish mineral. A qualitative analysis showed the
presence of silica, alumina, lime, magnesia, soda, a trace of
potash and iron, water and fluorine, the last in very feeble
quantity.

The quantitative analysis of this species is still incomplete
as to its alkaline constituents, which are given by the difference,
and the amount of water is probably placed too high*. The
analysis was conducted, under my direction, by my pupil,
Mr. W. J. Cravve. Three analyses gave him as follows : —

I. 11. irr. Oxygen.

Silica .... 32-311 31-060 31*261 16-24: = 4

Alumina . . • 4.9-243 51-199 51-603 23-74. 6

Lime .... 10-663 9-239 10-1461

Magnesia . . . 0-298 0-283 0-499 k 3-42 ^j,! jl

Soda and potashf 2-215 2*969 1-221 J ^

Water .... 5-270 5*270 5-270 4.*72 1

100-000 100-000 100-000
It is obvious that this is very nearly the true constitution of
the mineral. The following formula corresponds very closely
with the analytical results, viz. —

SRO, 4Si03, 6A103 + 3HO = 3(CaO, NaO, MgO)Si03
+ 3(2A103, Si03) + 3l-IO.

4 atoms Silica . . 2309-24 30*51 per cent.

6 ... Alumina . 3854-00 50-92

3 ... Lime . . 1068-06 14-11 Ai','Oi8E

3 ... Water . . 337-44 4-46

7568-74 100-00

This result leaves but little doubt that the mineral here
examined is the same as the Turkish emerylite. That the
American species will be found constant in containing water
I have no doubt.

Great care was bestowed on the trials to detect zircon ia,
but none was found.

Corundellite. '^^

The next mineral belonmng to this series Ihave called'*

Corundellite. This species in external characters much re**

• The mean of two determinations. f By the differenci^ ^^fj

Prof. B. Silliman on some American Mitierals. 453

sembles the last, but its composition is different in important
particulars. It is also found associated with the corundum
and emery of Unionville, Chester County, Pennsylvania.
The specimen here analysed is marked " D," and was taken
by me in May last from the mineral collection of the Chester
County Cabinet formed by Mr. Williams. It is in broad
foliated masses of a yellowish-white colour, easily cleavable,
and apparently hexagonal in form, penetrated by hexagonal
crystals of corundum. Inelastic, brittle ; resembles common
mica, but not so strikingly as A. Hardness, 3*5. Gravity, 3.
B. B. gives the same characters as the last species. No reac-
tion could be obtained for lithia or boracic acid in any of the
minerals of this series. The reaction for fluorine in this one
was feeble. It is unaffected by strong acids even on long
boiling, except partially by very strong sulphuric acid. Its
qualitative analysis gave silica, alumina, lime, potash, soda and
water, with a trace of iron and fluorine.

The following analysis was made by Mr. J. J. Crooke, on
r389 grm. of the substance fused with carbonate of baryta.
It yielded —

Oxygen.

Silica .... 0-496 = 35-708 p. c. 18'553=18*55= 9

Alumina . A '. 0-738 53-131 24-872 24-87 12

Lime . luu iui* 0-101 7*271 2-042^

Potash -^Tevabaoqi 0017 1-224 0-207 [- 2-36 1

Soda 0-006 0-413 0-1 loj

Water and fluorine 0-032 2-303 2-050 205 1

1-390 100-068
This gives the ratios
3Si03, 4 Alb^, RO + HO= RO, SiO^ + 2(2Alb% SiO^) + HO.

Atoms. Required. Found.

3 atoms Silica

. 1731-94 =

= 36-31 percent. 35*708

4 atoms Alumina

. 2569-32

53-87 53-131

1 atom Lime . .

356-02

7-46 8-926

1 atom Water

. 112-48

2-36 2-303

4769-76 100-00 100-068

This species somewhat resembles margarite, and it may be
shown on further examination that margarite is a hydrated
mineral. At present it is reported as anhydrous, and its pro-
portions of silica and alumina are different from the present
species. Its analysis, given by Hausmann on the authority of
the Gottingen Laboratory, is —

454 Prof. B. Silliman on some American Minerals.

Silica . 4618-48 34*47 p.cafc
Alumina 7708-00 57-55
Lime . 1068-06 7*98

Silica . .

33-50 =

= 8 atoms.

Alumina .

58-00

12

Lime . .

7-50

3

Protox.iron

0-42

Manganese

0-03

Magnesia .

0-05

13394-54 IGO'OO

99-50

3R0, 12Ar03, 8Si03=3RO, 2Si03 + 6{2Art)3, SiO^).

Possibly a new analysis may bring these species together.

The species corundellite occurs not only in the broad fo-
liated masses above alluded to, but also in small scales disse-
minated throughout the mass of granular corundum at Union-
ville, Pennsylvania, and in this form is quite abundant. Not
unfrequently these scales have a delicate shade of violet, espe-
cially when wet. The rock is difficult to break, and the co-
rundellite appears to adhere very strongly to the associated
minerals, and the laminae are not so easily separable as in the
foliated masses*.

Euphyllite.

This beautiful pearly white mineral is found associated with
black tourmaline and corundum at Unionville, Pennsylvania.
Form, apparently hexagonal; cleavage, eminent on basal
plane; the lamina) not so easily separable as in mica. Hard-
ness, 3. Gravity, 2-963. Lustre of sides, faint pearly; of
basal plane, very brilliant pearly, resembling Heulandite, but
perhaps more brilliant even than in that species. Colour of
cleavage, face pure white, of sides grayish, sea-green or whitish.
Laminae, rather brittle, inelastic, and quite transparent. ,

B. B. exfoliates, fuses on edges of thin laminae, and emits a*
stronger light than either of the corresponding species. In
the matrass it evolves water, and gives a reaction for fluorine.
No reaction for lithia or boracic acid was obtained, but it
gives a soda-yellow to the flame.

The qualitative analysis of this mineral gave silica, alumina,
lime, magnesia, soda, water and fluorine.

The quantitative analysis was conducted by Mr. J. J. Crooke,

* The species barsowite (G. Rose) appears in the Ural to hold the
same geognostic relations to corundum as do the minerals of the present
memoir in this country. Its composition however is quite distinct (silica,
49*01 ; alumina, 33-85 ; lime, 5-46; magnesia, l*55=99-87,Varrentrapp),
while its hardness, 6, and absence of micaceous structure, render it entirely
distinct. It approaches scapolite in composition, but with a smaller quan-
tity of protoxide. I am led to allude to this species from the fact, that an
intelligent foreign mineralogist, to whom I showed some of the corundel-
lite, remarked that there appeared to be a similarity between the species.
There is however a most marked difference, in that corundellite is a mica.

Prof. B. Silliman on some American Minerals. 4-55

and gave on fusion with carbonate of baryta the following
results, viz. quantity taken, 1*378 grni.; found-
Oxygen.
20'28 = 15
23-99 18

Silica .

. 0-538 =

= 39-042 per cent.

Alumina

. . 0-708

51-378

Lime . .

. 0-04<4.

3-193

0-897

Magnesia ,

. 0-015

1-088

0-421

•Soda , .

. 0-012

0-871

0-223

Water

. 0-063

4-593

1-380

100-165

1-54
4-08

This gives the following as the theoretical composition of
the mineral : —

5 atoms Silica . . .

. 2886-55 =

39-02 per cent

6 atoms Alumina . .

. 3854-00

52-10

1 atom CaO, MgO . .

319-38

4-32

3 atoms Water . . .

337-44

4-56

73-97-37 100-00

The following formulae therefore express its constitution: —

5Si03, 6Art)3, RO + 3HO=RO, Si03 + 2(3Alt)3, 2Si03)
+ 3HO.

The alumina obtained in this analysis (as well as in all the
others) was very critically examined for zirconia, but without
success.

The black tourmaline which is associated with euphyllite
has left the impression of its crystals on the lateral face of the
mineral with such a smooth hard-looking surface that it shows
no trace of a micaceous structure. The tourmaline has an
uncommon form, the faces 11 of the primary form being rudi-
mentary from the extension of the tangential plane, truncating
the summit.

The beautiful foliee of this pearly white mineral have sug-
gested the name euphyllite as an appropriate designation for
the species, while the name corundellite has the same obvious
derivation as enierylite, the mineral described by Dr. Smith.

There is a similar mineral associated with the blue corun-
dum of North Carolina, which was made known to mineralo-
gists by the Hon. T. L. Klingman, M.C.,from North Carolina.
It occurs investing the corundum. Colour, faint olive-brown.
Lustre, vitreous to pearly, like mica. In cleavable plates,
apparently hexagonal. Cleavage, perfect ; laminae, separable.
Hardness, 3. Gravity, 2-94 to 3*008. Brittle, transparent,
not acted on by strong acids. B. B. whitens, gives a brilliant

456 Prof. B. Silliman on some American Minerals.

light, but does not fuse, unless with great difficulty, on the
edges. It contains a trace of fluorine, and a qualitative ana-
lysis detected in it silica, alumina, lime, soda and water. An
insufficient quantity of the mineral prevented a perfect ana-
lysis being made. So far as its constituents have been ob-
tained, it contains, — silica, 36-369 ; alumina, 42-373 ; lime,
10141; magnesia, 4*462; water, 1-448; the difference, soda
and loss. Soda, about 4 per cent. '--^-^

Should it appear, on repeating the analysis of this mineral,
that it is new, as the present would appear to indicate, I would
propose to adopt the name Clingmanite, suggested by Prof.
Shepard, in honour of the distinguished gentleman before
named, who has shown great interest in advancing the study
of mineralogy*.

I have had no means of comparing the optical properties
of these several minerals. The angle between their axes of
polarization should be measured to ascertain if the differences
shown in their composition are found also in their molecular
structure. When we review the characters of the minerals
here described, we are struck with the almost identity of all
their ordinary physical characters ; and yet there are differ-
ences which are apparent, especially in their composition. It
therefore becomes an interesting question, to decide if the
optical characters will sustain the chemical results. The oc-
currence of a class of salts with such a very small amount of
protoxide bases, and so large a quantity of alumina as these
possess, is a novelty in the chemical history of minerals, and
may have some important theoretical connexions. Our know-
ledge of the whole mica family is quite imperfect at present.
The true function of the fluorine found in so many of them
yet remains to be explained ; and especially is it of the great-
est importance that a careful series of optical measurements
should be made on authentic specimens from numerous locali-
ties, and at the same time an exact series of chemical analyses
conducted on specimens from the same localities.

Mineralogy hardly offers a more inviting investigation than
this; and should it not fall into better hands, it will at a future
day be attempted in this laboratory.

* ^l^^i ^' ^' ^'^^P^''^ had noticed this mineral, and supposing it to be
new, he had determined to give it the above name. When he found, how-
ever, that I was engaged on this series of minerals, he promptly abandoned
the investigation. At that time we both thought that the emerylite of
Dr. Smith would probably include all the American species herein described,
which now appears not to be the fact. On going to England in June, Prof,
bhepard left me a memorandum containing his notes on the North Caro-
iiiia mineral, and I have embodied them in the above description with inv

nvvn *■ »

Prof. B. Silllman on some American Minerals. 457
-'■■ II. On Unionite. '''" i!'- < 'f •

'iro"> il. .<>'^mn'i

The next mineral to be noticed is from the same specimen
which furnished me the euphyllite. In general appearance it
somewhat resembles scapolite or spodumene. It is implanted
in black tourmaline, and is intimately associated with the eu-
phyllite. Its form is discernible only by its cleavages, which
are distinct in one direction, the planes dividing the mineral
into parallel laminae ; in two other directions less distinct, but
yielding a form probably triclinate*. Lustre, vitreous. Co-
lour, yellowish-white to white. Hardness, 6 to 6'5. Gravity,
3*2984. Brittle, and easily reduced to powder. In acids
does not gelatinize.

B. B. in forceps, it whitens, swells up and fuses to a white
enamel, giving out at the same time an extremely brilliant
light. In the matrass it gives out water which is acid, and
the glass is etched with hydrofluoric acid. Qualitative ana-
lysis detected silica, alumina, magnesia and soda. The
amount of water was determined by the loss on heating, and
the fluorine was not separately estimated. In the quantitative
analysis the mineral was attacked by carbonate of baryta.

The following are the results of analysis. Taken, 0*7335
grm. Yielded —

Oxygen.
Silica .... 0-32385=44'-l51p.c. 22-940 = 7

Alumina . . . 0-31000 42-263 19-763 6

Magnesia . . . 0*05400 7*361 2-85\ ,

Soda 0-01270 1-731 0-46J "^ "^^^ ^,

Water and fluorine 0-02590 3*532 ,,^ ^.j^'UG 1

Loss 0*00705 0-962 ■,!:!.

' 0-73350 100-000

7 atoms Silica. . . 4041-17 = 44-86 per cent.

6 atoms Alumina . . 385400 42*78

3 atoms Magnesia . 775*06 8*62

3 atoms Water . . 33744 3*74

9007-67 100*00

3RO, 6Alt)3, 7Si03, 3HO=3RO, Si03 + 6(Art)3, SiCF)
-F3HO.

This formula and constitution are believed to be unknown
in any previously noticed species among minerals, and I there-
fore propose it as new, and suggest for it the name Unionite,
derived from Unionville, its locality. At present it is a rare
substance, but I understand that .the place where it was found

* The angles do not admit of nieasurement.

458 Prof. B. Silliman on some Americati Minerals.

is to be worked soon for emery, and probably both it and the
euphyllite will be obtained there in abundance. This species
was also supplied to me by Mr. Williams of West Chester.

III. On Monrolite, a mineral resembling

WoRTHITE.

My attention was called to this mineral by [Mr. Wm. S.
Vaux of Philadelphia, who had received it from the locality
marked " topaz." It somewhat resembles pycnite in general
aspect, but as will be seen is a very different thing.

It occurs at Monroe, Orange Co., New York, where it is
found in a quartzose rock with magnetic iron, pink felspar,
black mica, pinite and common garnet. Colour green to
greenish gray. Structure radiating in sheafs from a centre in
groups from an inch to two inches in diameter. Also in
single implanted individuals. Cleavage and form of single
crystals resembles Sillimanite. Hardness, 7*25 on an angle ;
on cleavage face about 6. Gravity, 3-045, 3*096, 3*07. Co-
lumnar, fibrous. The oblique prisms were not measured,
being too irregular.

B.B. alone in tube gives off neutral water. Infusible,
whitens ; dissolves slowly in carbonate of soda, readily in bo-
rax and in salt of phosphorus, leaves a siliceous skeleton which
reacts slightly for iron.

Its qualitative assay indicated the presence of silica and alu-
mina, with a trace of iron and magnesia.

It was fused with carbonate of potash and caustic potash,
and its analysis yielded —

I. ir. III.

Silica . . . 40-92 40-389 40-389

Alumina . . 56-61 55-729 56'6\S

Magnesia . . '28 '280 -280

Water . . . 3-09 1-840 2-794

100-90 98-238 100-079

These analyses correspond closely with8SiO'', lOAtt)'^, 3H0.

8 atoms Silica . . 4618-48 = 40-59 per cent.
10 atoms Alumina. . 6423*30 56*44
3 atoms Water . . 337-44 297

11379-22 100*00
We have then the formula

8(Alt)3, Si03) + 2Afc)^ 3H0.
The Worlhite of Hess gave the formula—
5(A103, SiO^) + Alt)3, 3H0 corresponding to his analysis, viz.

Prof. B. Silliman on some American Minerals. 459

Silica . .

. . 40-79

Alumina . .

. . 53-06

Water . .

. . 4-63

Magnesia

. . 0-88

99-36

I have never seen the Worthite, and have therefore no
means of judging of the similarity of these two minerals in
other respects. The probability of being able to refer the
present mineral to kyaiiite seemed to me at first quite strong,
but I was unable by any care to procure an amount of silica
less than that given in these analyses Should this mineral
on further examination and comparison prove to be distinct,
I propose for it the name Monrolite, derived from the locality
where it was found.

IV. On the identity of Sillimanite, Fibbolite and

BUCHOLZITE WITH KyaNITE.

Sillimanite was orginally described by Bowen*, from an
analysis made in Yale College Laboratoy in 1825, which
showed it to be a silicate of alumina with a proportion of silica
too high to allow it to come within the formula of kyanite. It
was subsequently analysed by Dr. Thomas Muir, in the labo-
ratory of Dr. Thomson, who found in it a large quantity of
zirconia, an observation which all subsequent researches have
failed to confirm. Since that time it has been analysed by
various chemists ; viz. by Connel, Norton, Staff, Hayes and
Thomson. The most recent of these analyses which has been
published is that by Thomson, who reports it to contain 45*65
per cent, of silica. We have then the following discordant
results in the amount of silica found in Sillimanite by different
chemists in the order of their publication : —

1. 2. 3. 4. 5. 6. 7.

Bowen. Muir. Connel. Norton. Staff, Hayes. Thomson.

Percent. 42-67 38-67 3675 37*40 37*36 42*60 46*65

The cause of this disagreement will undoubtedly be found
in the difficulty of effecting a complete decomposition of an-
hydrous silicates of alumina, which contain a high per-centage
of alumina. This decomposition can be completely effected
only by the aid of caustic potash applied to the mixture of
carbonates and the mineral during the fusion, as first recom-
mended by Berzelius, or by hydrofluoric acid.

Select crystals of this mineral were taken from the original
locality at Chester, Conn., and their analysis afforded the
following results. Quantity taken, 775*5 grms. Found —

* Journ. Acad. Nat. Sci.Phil., iii. p. 375.

460 Prof. B. Silliman o« some American Minerals.

^-^C Silica' V'^?«"/^ . . 0-292 = 37-C53 per cent. T^
Alumina .... 0'4<84< 62-4.11

0-776 100-064.

Required.

2 atoms Silica . . . 1154.-62 = Si03 37-47

3 atoms Alumina . . 1 927*00 = Art)3 62-53

This result gives then exactly the formula of kyanite, viz.
2A1X)^ 3Si03. The analyses of Staff and Norton give also
the same result*.

We can therefore have no longer any hesitation in referring
Sillimanite to kyanite, as originally suggested by Haidingerf.

Biicholzite is a name given by Brandes to a silicate of alu-
mina from Tyrol, which occurs in compact masses of a finely
fibrous structure and hardness equal to kyanite. Thomson
has also analysed a mineral from Chester County, Pennsyl-
vania, well-known to collectors, and has referred it to Buchol-
zitej. Being in possession of authentic specimens of the
Chester mineral, I have analysed it with the following result.
Quantity taken, 0*561 grm. Found —

Another samole.
35-96 *

Silica . ,

. 0*1925

= 34*31 per cent.

Alumina .

. 0'3615

64-43

Magnesia . ,

. 0-0028

0-52

Manganese .

trace

trace

0-5568 99-26

This also will give us the same formula as kyanite. The
mineral being less pure than Sillimanite, cannot be expected
to furnish results as accurate as the former analysis. Prof.
Shepard in his System expresses the opinion that Bucholzite,
and Sillimanite were the same species.

There is also found at Brandywine Springs, Delaware, a
mineral which has been extensively circulated under the name
of both Bucholzite and fibrolite. A specimen from this locality

* In Prof. Norton's analysis, which was made in Yale College Labora-
tory, the excess of 2*73 was owing undoubtedly to aluininate of potash
which remained with the alumina after separating the peroxide of iron by
caustic potash. Subtracting this sum from the sum of alumina and per-
oxide of iron, we have 62'30 per cent, alumina and peroxide of iron, which
is almost exactly the quantity required by theory, and I have corrected the
analysis accordingly with the consent of Prof. Norton. That analysis was
made on the Sillimanite from Fairfield, New York.

-|- In his translation of Mohs, vol. iii. 154.

X Erdmann appears also to have made his analysis on the mineral from
tlie same locality.

Prof. B. SilHman on some American Minerals, 461

furnished me the following results, viz. quantity taken, r0675
grm. Found —

Silica . . . 0-386 = 36*159 per cent.
Alumina . . 0679 63-525

1-065 99-684.

This is evidently identical with kyanite. Minute traces of
iron and manganese, which are found in both the above, are
regarded as of no importance in the result, being mere impu-
rities*.

Fibrolite of Bournon. — This mineral was first distinguished
by Count Bournon, who detected it among the associated
minerals of corundum from India and from China. The
name has reference to its fibrous character. It was analysed
by Chevenix, who found —

Silica 38-00

Alumina 58'25

96-25 .shtav

Even upon so imperfect an analysis, there has been no he-
sitation with most writers in referring it to kyanite. Having
a specimen of this mineral from Count Bournon at my dis-
posal, I have analysed itf. It yielded on 0*427 grm. taken —

Silica . . . . 01 55 1 = 36-309 per cent.

Alumina . . . 0*2665 62*415
Magnesia . . 0*0030 0-702 '"ai: uei^:.

0*4246 99*426

The results just given leave it no longer possible for us to se-
parate Slllimanite, Bucholzite, and fibrolite from kyanite. The
hardness of Sillimanite proves also to possess the same inequa-
lity on different faces which is found in kyanite. The cleavage
face is much softer than the angle or side of the prism, so as

* It may be objected to the conclusion that Bucholzite is identical with
kyanite that I have not analysed a specimen of the original mineral. This
I should have done could I have procured one in time for my present
purpose. The Chester mineral here analysed was received by Baron Le-
derer from Dr. Nuttall, and so far as I can learn, no one questions that the
mineral from that locality corresponds entirely with the Bucholzite of
Brandes. I am convinced that those chemists who have obtained so high
a per-centage of silica in their analyses of disthene minerals, had not taken
the precaution to employ the aid of caustic potash, added to the assay
during fusion, as recommended by Berzelius ; and that if they had re-ana-
lysed their silica they would invariably in cases where the amount exceeded
38 per cent., have found in it a portion of alumina.

t The specimen referred to was taken from the collection of Col. Gibbs
(now in Yale College), and was received by him from Count Bournon in a
large collection of gems which this gentleman furnished to Col, Gibbs.. ^jj^

462 Prof. B. Silliman on some American Minerals.

to be easily scratched with a sharp point of hard steel. The
crystalline forms of Sillimanite and kyanite are also identical;
the one being derived by the simplest modification from the
other. The cleavage in both is in the orthodiagonal.

It may be vi^orthy of remark that " Andalusite " has the
same chemical constitution as kyanite, but belongs to the right
rhombic form, while kyanite is oblique. Doubtless a case of
dimorphism, and perhaps the same may be said with truth of
staurotide.

My pupil, Mr. George J. Brush, afforded me essential aid
in the foregoing investigation.

V. On the Boltonite of Shepard, and Thomson's
BisiLiCATE OF Magnesia.

The mineral named Boltonite by Prof. Shepard *, is found
at Bolton in Massachusetts, in a lime quarry, disseminated in
irregular masses, seldom showing any traces of crystalline
form. The description of Prof Shepard is quoted below f.

The changes of colour are peculiar ; and often the same
mass, which is dark greenish-gray on one end, will have turned
light yellow on the other J. Hardness, 5*50 ; specific gravity,
3*008 — the same on two specimens, one dark and one light.

This mineral, when first found, was called Pyrallolite, and
is now so labeled in some old collections. Baron Lederer's
cabinet of American minerals, now in the Yale College col-
lections, contains eight or ten specimens of this mineral from
Bolton, under the name Pyrallolite, which were received, as
the catalogue indicates, from Robinson, Shepard, Nuttall,
Boyd, and other of the early cultivators of American mine-
ralogy.

In his remarks on this mineral. Prof. Shepard says, it is
believed to be identical with the substance described by Dr.
Thomson § under the name of" bisilicate of magnesia;" and
accordingly the analysis of Dr. Thomson is quoted under

* Shepard's Treatise on Mineralogy, Newhaven, 1835, vol. i. p. 78.

t Prof. Shepard's description is as follows — " Massive, composition gra-
nular : individuals large, cleavage in one direction pretty distinct, in two
others oblique to the first, indistinct, but affording indications of a doubly
oblique prism, fracture uneven or small conchoidal. Lustre vitreous.
Colour bluish gray, yellowish gray, wax yellow to yellowish white. The
darker colours change to yellow on exposure to the weather. Hardness,
5-0-60. Gravity 2-8-2-9."

J Mr. Saemann of Berlin, Prussia, in a paper read before the Am. Assoc.
for the Promotion of Science at Cambridge, attributes the change of colour
in boltonite to minute grains of magnetic iron found disseminated in the
substance of the crystals, which, undergoing change by exposure, leave the
mineral of a lighter colour than it was when fresh.

§ Am, Lye. Nat. Hist., New York, vol. ill, p. 60,

Prof, B. Silliman 0}i some American Miiierals. 463

" Boltonite," as giving the supposed chemical constitution of
this substance.

It will presently be shown that there is every probability
that Dr. Thomson applied the name bisilicate of magnesia to
another substance ; and that the boltonite of Prof, Shepard is
not the substance which he analysed.

Having received specimens of boltonite from Mr. Saemann,
a very intelligent and discriminating mineralogist from Berlin,
I was induced to undertake an analysis of it, which gave me
the following results. The specimen analysed was the yellow
variety. 0*5753 grm. of substance gave —

Oxygen.

Silica .... 46-062 = ... 23-23 = 8'"

Alumina . . . 5*667 ... 2-64 1

Magnesia . . . 38-149 14*76^

Protoxide of iron 8*632 1*95^ = 17*14 6*.'

Lime .... 1-516 0-43

100-026
Formula SSiO^ 1 Alt)^ 18MgO = 2RO, (SiO^, Alt)^), or
2(MgO, CaO, FeO), (SiO^, AW).

8 atoms Silica . . . =370-08 = 46-556 per cent.
1 atom Alumina . . 51-47 6-372

18 atoms Magnesia . 372-66 47*072

794-91 100-000
If we consider the alumina as not an essential constituent of
the mineral instead of replacing a part of the silica (a view
which I am not disposed to take), then we shall have a silicate
of magnesia and the other bases, whose formula will be
9RO, 4Si03.
Referring to Thomson's analysis and description of his bi-
silicate of magnesia, we read {loc. cit. p. 50) that the mineral
received by him from Mr. Nuttall (from Bolton, Massachus-
setis) bears so much resemblance to the picrosmine of Hai-
dinger, both in character and composition, " that he strongly
suspects the two things to be mere varieties. The mineral is
white, with a shade of green ; powder white. It cofisists of a
congeries of prismatic crystalSf very irregularly disposed^ and
involved in each other. Lustre glassy; transparent on the
edges." The analysis gave —

Silica 56-64

Magnesia . . . 36-52

Alumina .... 6*07

Peroxide of iron . 2-46

101'69

464 Prof. B. Silliman o« some American Minerals,

This analysis must certainly refer to another mineral than
boltonite. The description certainly does not compare at all
with that of boltonite, which cannot be said to "consist of a
series of prismatic crystals," with a glassy lustre and faint
green colour. Nor is it white. In searching among the
minerals from Bolton, in the cabinet of Baron Lederer, for
something corresponding with Thomson's description, I found
one from that locality marked " Picrosmine? " " Actynolite ?"
This mineral answers the description of Thomson, quoted
above, as nearly as anything could ; and is undoubtedly the
same thing which he received from Mr. NuttalJ, and examined
with the above results. Nothing else occurs at the locality at
all resembling the mineral which is described by Dr. Thomson.
A qualitative analysis of this specimen gave silica, magnesia,
alumina, peroxide of iron, manganese, but no lime or water.
These are the constituents of a hornblende, and this specimen
is undoubtedly such — variety actinolite*.

If the foregoing conclusions are correct, it would appear
that boltonite and " bisilicate of magnesia " are not the same
mineral as described by Prof. Shepard.

The formula for boltonite is that of a salt not before de-
scribed, while that deducible from Thomson's analysis, cor-
responds as accurately as we could expect with common
hornblende.

I am happy therefore to be able to re-establish boltonite as
a species on good grounds.

VI. On Nuttallite.

Nuttallite was established as a species by Mr. Brooke t> on
general physical grounds, principally of hardness and colour,
and a slight departure from the usual angles of scapolite. It
was analysed by Thomson J, who found for it a constitution
so different from scapolite, that it has been regarded as a di-
stinct species by many mineralogists, and is so placed by
Nicol in his Manual just published. I was induced to make
a new analysis to decide the doubt regarding its true constitu-
tion. The mineral is partially decomposed by strong hydro-

* I am altogether at a loss to understand what Dr. Thomson intends,
when he says in his memoir before quoted, that the analysis here given
corresponds to the constitution of a " bisilicate of magnesia.'' For
2 atoms SiO' = 92-52 = percent. 8172
1 atom MgO = 20-70 18-28

113-22 100-00

This result is entirely different from his analysis,
t Ann, of Philos., xli. p. 366.
i New York Lyceum of Natural History, vol. iii. p. 82.

Intelligeme and Miscellaneous Artftlei. 465

cliloric acid with heat, but it is not thus possible to obtain a
complete analysis. The mineral is found at Bolton, Mass.,
in a white cleavable limestone with black augite. Having a
good specimen, I requested Mr. Ludwig Stadtmuller, one of
our pupils, to undertake the analyais. The following are the
results confirmed by several trials; the alkaline constituents
being determined by fusion with carbonate of baryta. ^^

Silica ....

45' 791

Alumina ...

30'107

Peroxide of iron .

1-861

Lime ....

17-406

Potash ....

3-486

Soda 1 . .
Manganesej . .

traces.

Water ....

1-630

100-281

It is obvious from simple inspection, that this analysis cor-
responds exactly with scapolite, and we have no hesitation in
referring Nuttallite to scapolite.

LVII. Litelligence and Miscellaneous Articles. 'o%

oil

ON THE STATE IN WHICH ARSENIC EXISTS IN THE DEPOSIT
FROM MINERAL WATERS. BY M. J. L. LASSAIGNE.

SINCE the discovery of the presence of arsenic in the deposits from
certain chalybeate mineral waters, it has been asked whether
the poisonous properties of this substance are not neutralized by the
state in which it is found. No experiment having been yet under-
taken on this subject, the author, at the request of M. Chevaliier,
has made several experiments. The object in undertaking them
was to determine the proportion of arsenic contained, in what state
of combination it existed, and the nature of the action which these
arseniferous deposits exerted on the animal oeconomy.

The first experiment was made on the deposit from the waters of
Wattviller (Haut Rhin). In order to ascertain the quantity of
arsenic, a portion of the residue was treated with nitro-hydrochloric
acid, to convert all the arsenic which it might contain into arseniate
of iron.

This residue, washed with distilled water, was calcined in a silver
crucible with twice its weight of hydrate of potash ; the product of
this calcination was treated with hot distilled water, and the liquid
was filtered to separate the insoluble deposit ; the filtered hquid was
supersaturated with nitric acid, and the solution evaporated to dry-
ness. The residue, redissolved by distilled water, gave a solution to
which was added solution of acetate of lead ; this produced a white
flocculent precipitate which was collected on a weighed filter. This

Phil. Mag. S. 3. Vol. 35. No. 238. Dec. 1 849. 2 H

466 Intelligence and Miscellaiieous Articles.

precipitate was recognized as arseniate of lead, — 1st, by the alliaceous
odour which it evolved when calcined on charcoal by the blowpipe ;
2ndly, by the brick-red colour which it immediately yielded by moist-
ening it with a neutral solution of nitrate of silver. From the
weight of this arseniate of lead, the quantity of arsenic contained in
the deposit from the waters of Wattviller, was deduced. This ex-
periment showed that 100 parts of the deposit, previously treated
with nitro-hydrochloric acid and afterwards dried, yielded 4'42 of
arsenic acid, containing 2*8 of metalHc arsenic.

After having determined the proportion of arsenic, a direct expe-
riment was atttempted to determine the effect of this deposit on the
animal oeconomy. This experiment was made with a fresh quantity
of the same deposit, furnished by M. Chevallier.

Forty grammes of this deposit, divided into two portions, were
forcibly given to a middle-sized young dog. Each dose of 20
grammes was diffused through a decilitre and a half of slightly viscid
honeyed water, and gradually introduced into the throat of the
animal. This liquid, which was swallowed without any apparent dis-
gust, occasioned neither vomiting nor uneasiness, for on offering
bread to the animal three quarters of an hour after swallowing, it
was readily eaten. The second dose was administered in the same
manner, and afterwards the animal eat about three ounces of brown
bread. No alteration of appearance could be detected by an atten-
tive examination of the animal, during six hours from the commence-
ment of the experiment, and no difficulty was observable in its diges-
tion, even in twenty-four hours. After this time the animal was re-
stored to bis usual diet, and there was no apparent alteration in his
health.

The following conclusions may be fairly drawn from this first ex-
periment : —

1st. In the natural deposits of the mineral waters of Wattviller,
arsenic exists to the amount of 2*8 per cent.

2ndly. A portion of these deposits, representing 1-76 gr. of arsenic
acid, or 1-14 gr. of arsenic, produced no effect upon the health of a
dog.

i3rdly. This non -action shows that the poisonous property of the
arsenic contained in these deposits, is destroyed by its combination
with peroxide of iron.

4thly. This result confirms what experiment has already shown,
that peroxide of iron, by combining with arsenious and arsenic acid,
destroys their poisonous properties, and consequently becomes an an-
tidote for them, as proved long since by the direct experiments of
MM. Bunsen and Berthold Font.

A second chemical experiment was made upon a certain quantity
of the deposits of the waters of Royat (Puy-de-P6me), sent to the
author by M. Chevallier; in this deposit, in which M. Chevallier and
M. Gobley had ascertairied the presence of arsenic, it was found to
amount to only ^^j^^dths, and in the state of arseniate.

The last conclusion was deduced from the presence of arseniate of
iron and of lime, which was obtained from the deposit in hydro-

Intelligence and Miscellaneous Articles, 467

chloric acid and treatment of the dry residue with alcohol. The
small quantity of pulverulent matter, of a chamois yellow colour,
which remained insoluble, consisted of arsenic acid, peroxide of iron
and lime.

The author will not undertake to decide that the acid is combined
with these two bases in the deposit ; it being possible that a part of
the subarseniate of iron had been decomposed during the operation
by carbonate, of lime, of which the deposit from the waters of Royat
contains a large quantity.

Two hundred grammes of this deposit were divided into six por-
tions of 33 grammes. Each dose was diffused through honeyed water
and] given every two hours to the same dog ; three doses were
given in one day and three others the next ; the animal showed no
peculiarity during the experiments, and continues healthy and lively.
— Journ. de Chem. Med., Septembre 1849.

EASY MODE OF MEASURING SOLAR OBJECTS.

To the Editors of the Philosophical Magazine and Journal.

Gentlemen,
I am not aware whether the expedient is generally known of mea-
suring the solar spots by placing a graduated glass scale on the dia-
phragm of the eye-piece and casting the sun's image upon a white
ground. The divisions of the micrometer become thus more palpa-
bly distinguished, and the excess covered by the spots is more accu-
rately estimated by the eye than when looking direct through the
telescope. In this way also an angle can be measured in any direc-
tion by merely turning the eye-piece round on its axis. It greatly
saves the eye-sight, and is serviceable when only brief glimpses are
to be obtained and expedition is required. Although perfect accu-
racy may not be attained, it may serve at least for general purposes.

Should the suggestion seem to you worth noticing, I beg to leave
it to your disposal.

I am, Gentlemen,
Edinburgh, Nov. 12, 1849. Your obedient Servant,

W. Pringle.

NATURAL SOURCES AND NEW MODE OF PREPARING SULPHURIC
ACID. BY M. C. BLONDEAU.

Abundant sources of sulphuric acid exist in Nature. M. Bous-
singault has described several acid waters in America, and particu-
larly the llio-Vinagre or Pasiambo, of which 1000 parts contain 2
parts of sulphuric acid. According to M. Boussingault's estimate,
the Pasiambo supplies 38610 kilogrammes of sulphuric acid in 24
hours, and this quantity is much exceeded by the discovery made
in the Paramo de Riuzby M. Degenhart, the water there containing,
according to M. Lewy's analysis, three times as much sulphuric acid
as the Pasiambo. Whence come these enormous quantities of the
acid? what are the processes which nature employs in their formation ?

2 H2

'l-GS Intelligence and Miscellaneous Articles.

The author states, that a phenomenon which he observed in the de-
partment of Aveyron, gave him an opportunity of describing the na-
tural formation of an acid so much employed in the arts, and which
placed him in a condition in the localities which he has examined, of
readily manufacturing sulphuric acid, without having recourse to the
complicated processes generally employed.

In the coal-measures of Aveyron, and particularly in the environs
of Cransac (arrondissement de Villefranche), the spontaneous com-
bustion of the soil is observed to occur, v/hich is evidenced by the
disengagement of gas and vapours, which at a distance resemble
a small volcano. On approaching the place where this combustion
occurs, it is evident that the earth has been mined, and large crevices
are discovered from time to time, from which there is emitted much
aqueous vapour and acid fumes. At the edges of these fissures the
heat becomes intolerable, and surprise ceases to be excited that the
effects of this heat, combined with the action of acid gases, should
have modified so completely the places in which these chemical ac-
tions occur.

In some spots of the burning mountain, there occur enormous
rocks formed of conglomerates, which, having undergone the action
of fire, are completely changed in appearance, and are united by a
censent, which owing to the action of heat has a brick-red colour.

The surface of the burning mountain consisted of grits, schists and
argills; these substances have assumed the appearance of chalcedonies,
jaspers, enamels, glass and bricks, and sometimes even the cavernous
appearance of volcanic stones. The aggregations which these sub-
stances have formed with argill have in some cases acquired the
hardness of the most compact stones. The soil, gradually mined
by the chemical agency occurring within it, eventually sinks, occa-
sioning the formation of foundries, which, by their conical form, re-
semble in some degree the craters of volcanos ; it is through these
vents that columns of vapour are disengaged, which sometimes rise
to a great height in the air, and are at other times dispersed by the
wind in the valleys.

In these places a number of saline concretions, efflorescences, cry-
stals of sulphur and hydrochlorate of ammonia are met with ; these
products have been converted to useful purposes, and dissolved in
rain-water, they constitute the mineral waters frequently employed
in the locality now described.

The causes of the phsenomena become evident to any one who has
ascertained the presence of sulphuret of iron, which occurs abun-
dantly in the various strata of coal country which constitute this
locality.

This sulphuret, in contact with water and with atmospheric air,
burns and gives rise to sulphurous acid gas, which is converted into
sulphuric acid by the influence of air and of bases, such as alumina
and oxide of iron. The sulphates of iron and alumina which form
under these circumstances are decomposed by the action of heat, and
sulphuric acid is set free.

The temperature resulting from these diflferent reactions is some-

Inlelligence and Miscellaneous Articles. 469

times sufficiently high to occasion the combustion of the coal-beds
which are near the surface, and the products of the combustion of the
coal are added to the vapour of water and of sulphuric acid, and thus
increase the grandeur of the phtenomenon. The sulphuric acid which
arises under the conditions described, exerts a very energetic action
on the mineral and organic substances which it meets with in its
passage ; the trunks of the trees which occur in the neighbourhood
of the burning mountain are covered with the black colour of sub-
stances which have been immersed in sulphuric acid. Mineral sub-
stances are also strongly acted upon by this powerful acid, which
simultaneously attacks silica, alumina, lime, oxide of iron, the earths
and alkalies which enter into the composition of rocks, and eventually
sulphates are produced, among which is the double sulphate of pot-
ash and alumina (alum) in sufficient quantity to be useful.

The author analysed the efflorescences collected on the burning
mountain of Cransac. These efflorescences were w^hite, strongly
acid, reddened tincture of litmus, and attracted moisture from the
air. After drying in vacuo by the air-pump, 50 grammes were dis-
solved in a litre of distilled water, and the solution was treated as if
it had been a common mineral water

The results of the analyses were : —

Sulphate of potash and alumina . . 24*25

Sulphate of alumina . . . , . . 53" 31

Sulphate of magnesia 3*47

Sulphate of manganese ..... 1*35

Sulphate of iron 10"29

Free sulphuric acid , 7'33

100-00
On examining the natural process which gives rise to the large
quantities of sulphuric acid, occurring not only combined with bases,
but also uncombined, it occurred to M. Blondeau to examine whether
under similar conditions sulphuric acid might not be immediately pro-
duced from sulphurous acid gas.

For this purpose some argillaceous sand was put into a porcelain
tube, one of the ends of which communicated with two vessels, from
one of which sulphurous acid, and from the other vapour of water
was disengaged, and at the same time air was passed into the in-
terior of the apparatus by means of a gasometer. At the other end of
the porcelain tube a bent tube was adopted, which was immersed in
water in a two-necked bottle, to one of which was fixed a disengaging
tube. The apparatus thus arranged, the porcelain tube was sur-
rounded with burning charcoal, so as to heat it to dull redness, and
the sulphurous acid gas, air and the vapour of water were slowly
passed into it. The substance disengaged at the end of the tube was
sulphuric acid ; taking care to supply an excess of air, but very little
sulphurous acid is disengaged, the whole of it being converted into
sulphuric acid.

To gu from this laboratory experiment to a manufacturing one,
sulphurous acid must be produced by the combustion of sulphur or

470 Intelligence and Miscellaneous Articles.

sulphurets, and the products of the combustion passed into a cylinder
of cast-iron strongly heated and containing argillaceous sand, passing
into it at the same time excess of the vapour of water. The sul-
phuric acid will be received at the other end of the cylinder. The
author is of opinion that no doubt can be entertained of the supe-
riority of this plan to that which is at present adopted, and that by
employing an apparatus thus constructed, sulphuric acid will be
procured at a lower price than is at present the case. — Comptes
Rendus, Oct. 15, 1849.

NOTES ON THE CALIFORNIA GOLD REGION.
BY THE REV. C. S. LYMAN*.

From the western base to the summit of the range of the Sierra
Nevada, is a distance generally of a hundred miles, or more. The
western slope is broken and precipitous, and through the deep ra-
vines that abound, flow the numerous mountain streams that form
the tributaries of the Sacramento and San Joaquin rivers. The gold
region is a longitudinal strip or tract from ten to forty miles in width
lying about midway, or a little lower, between the base and summit
of the range, and extending in length a distance of many hundred
miles — active operations being already carried on through an extent
of four or five hundred miles at least. The gold mines near San
Fernando in a spur of the same range, and which have been known
and worked to some extent for many years, are doubtless a part of
the same great deposit.

On approaching the gold region from the valley of the Sacramento
or San Joaquin, soon after leaving the plain, the attention is arrested
by immense quantities of quartz pebbles, slightly rounded, and of the
size of walnuts, scattered over the gentle elevations which form the
western base of the Snowy Mountains. There is here but little soil
■ — the earth is of a yellowish red colour, and nearly destitute of ve-
getation. Nearer to the gold deposits the quartz pebbles become
larger, and not unfrequently boulders are noticed of considerable
size. The quartz is so uniformly associated with the gold, that even
the most unscientific explorer would not think of looking for the
metal where quartz did not abound. Passing up the mountains it is
easy to tell when you leave the region of gold from the sudden dis-
appearance of the quartz. In August of last year, in company with
Mr. Douglass and others, I ascended from the " dry diggings,"
near the Rio de los Americanos, to within a few miles of the snow,
enjoying in the highest degree the sublime scenery presented by lofty
and precipitous mountains, separated from each other by dark, deep
ravines, and wooded with primaeval forests of towering firs and pines.
The backbone of this mountain range is granite, the several varieties
of which constituted almost the only rock visible in the last few
miles of our journey. In descending we passed successively several
forms of gneiss and other primitive and transition rocks, till we

* In a Letter to B. Silliman, Esq., dated Puebla de San Jose, March
27, 1849.

Intelligence and Miscellaneous Articles. 471

reached the slate formation which prevails in this part of the gold
district. We penetrated on this occasion some forty or forty-five
miles beyond the " dry diggings," and after leaving the quartz twelve
or fifteen miles up, scarcely a particle of gold was discovered.

As I have mentioned, the prevailing rock of the gold region near
the Rio de los Americanos is slate. There are many varieties of it
— some shaly and friable, others hard and massive, somewhat resem-
bling greenstone. The laminae of the slate beds are nearly perpen-
dicular, and their direction about N.N.W. and S.S.E., or nearly the
same as the direction of the range. These slate beds often include
dykes or beds of quartz rock several feet in thickness. At the dry
diggings above-named, I passed at right angles over the upturned
edge of continuous strata of slate a distance of four or five miles ;
and in the same direction, slate beds occur several miles further on,
but I had not the means of knowing that they were a part of the
same great deposit.

In some of the richest explorations yet made, the slate formation
immediately underlies the stratum of drift or diluvium which con-
tains the gold, and much of the gold is found in the crevices of the
slate, the rough edges of the upturned strata forming innumerable
receptacles or "pockets," as they are called, into which the metal has
originally found its way, from its own gravity assisted by aqueous
agency. It is this accidental association of the gold with the slate
rocks which has caused the statement to be frequently made, even
by persons of much general intelligence, that the gold exists in
the body of the rock itself, and forms a component part of it, in the
same sense that iron pyrites forms a part of the rocks in which it
occurs. But I have nowhere seen gold among the slate, except in
circumstances where its presence could be accounted for by its in-
troduction from without, a close scrutiny readily discovering some
cleft or opening through which it might have entered. The richest of
these " pockets" are in the bottoms of sharp ravines which seem to
have been notched into the body of the slate, and generally in situ-
ations where the bottom of the ravine, after descending at a consi-
derable inclination for some distance, becomes more nearly horizontal.
Just below a sudden descent or precipice, in the bottom of a dry ra-
vine, gold is often found in the cavities in great abundance, From
such a spot Mr. Douglass extracted a pound of gold in a few hours,
even after the place had been previously "dug out," as was sup-
posed, and abandoned.

I have noticed in published accounts, many erroneous statements
respecting the geological position of the gold. Some have said there
is no particular formation in which the gold occurs, but that in dif-
ferent places it is found in different kinds of earth or rock. You will
not need to be informed that this is without foundation. So far as
I have been able to examine, or can learn from competent witnesses,
there is but one geological formation with which the gold of the
Sierra Nevada is associated and in which it uniformly occurs. This
is the stratum of drift or diluvium, composed of a heterogeneous mix-
ture of clay, sand, gravel and pebbles, and varying in thickness from

472 Intelligence and Miscellaneous Articles.

a few inches to several feet. Here, as elsewhere, this sti'atum is
neither horizontal nor of uniform slope, but conformeil to the vary-
ing inclination of the earth's surface, covering the declivities, and
even the summits of the hills, as well as the bottoms of the ravines
and valleys. Out of this stratum I have nowhere found gold, ex-
cept where a stream has cut it away and made its contents a part of
some alluvial formation of comparatively modern date. The sand-
bars of some of the mountain torrents, and the gravelly projections
formed at the bendings of the streams, are often extremely rich iu
metal. A bar in the Rio de los Americanos (at high- water an island),
about twenty- three miles above New Helvetia (now called Sacra-
mento), and on which some of the earliest explorations were made, is
of this character. But where the diluvium has remained undisturbed
since the period of its deposition, I am confident no "alluvial" or
*' stream " gold has been, or will be discovered, except in connection
with it. It is evidently as much '■' part and parcel " of this forma-
tion as its associated quartz, greenstone, hornblende, and other peb-
bles, and whoever will explain the origin of the one, will at the same
time elucidate the origin of the other, for one and the same agency
unquestionably spread both of them over the surface of the district.
What the latest theory of geologists is to account for the dispersion
of drift, I am too isolated from the scientific world to know. Quartz
is the only substance with which I have seen the gold intimately
united, and these compound lumps seem to show clearly that the
original matrix or vein-stone of the metal was a dyke or bed of quartz
rock. And we have only to suppose, that when the quartz, with its
accompanying rocky strata, was broken up by natural agencies at
some former geological epoch, the interspersed or included veins of
gold were at the same time reduced to fragments, and these rough
and angular fragments subsequently broken and further comminuted
and rounded by mutual attrition, to account for the present form and
appearance of the gold, and for its constituting a portion of the ma-
terials of the drift. But whether these materials with their golden
treasure, now occupy the precise geographical position of their pa-
rent rocks, or whether they have been transported by aqueous or
glacial agencies or both, from some neighboui'ing or perhaps far di-
stant locality, is a question which future investigations into the geo-
logy and physical geography of the region will better elucidate than
the imperfect data at present in my possession. I cannot avoid the
fancy, however, in connection with the glacio-aqueous theory, that
when the continent was wholly or partially submerged, the materials
of the diluvium, including the gold, were transported by icebergs
from their parent locality, and when at length set free, left to assume
their present position on what was then the rocky and uneven bot-
tom of the superincumbent ocean. And we have only to imagine
these freighted icebergs stranded by oceanic currents against the
partially emerged range of the Sierra Nevada, to account for the
great longitudinal extension of the gold region along the western
slojje of the mountains, while laterally it appears to extend neither
above nor below certain definite limits.

Intelligence and Miscellanemis Articles. 4-73

"is

The gold of different localities varies very much in size. That
from the banks and sand-bars of the rivers, is generally in the form
of small flattened scales, and commonly it is found to be finer the
lower down you descend the stream, 'i'hat taken from the bottoms
of the dry ravines, which everywhere abound in these mountains,
and furnish outlets for the torrents of the rainy season into the prin-
cijDal streams, is mostly of larger size, and occurs both in small par- ■
tides and also in small lumps and irregular water- worn masses, from
the size of wheat kernels to pieces of several ounces or even pounds
in weight. The fine gold of these ravines is commonly less worn
and flattened than that in the alluvium of the rivers. And the flat-
tened scale- like form of the gold in these latter deposits would seem
to be owing to the great malleability of the metal — the stones and
jiebbles among which the minuter particles and fragments of the
original vein of native metal chanced to lie, and hy which they were
rudely hammered, having performed very effectually the gold-beater's
otHce, and gradually reduced the rough angular particles, on their
granite anvils, to the flattened spangles which we now observe.
Some of these flakes are often an inch or more in diameter and
scarcely thicker than paper. Many specimens bear the distinct
impression of the crystalline structure of granite and other rocks ;
and I have seen several pieces deeply stamped, as with a die, by
crystals of quartz, the form of the crystal being as distinctly apparent
as the device on a gold eagle fresh from the United States mint.

The black, ferruginous sand, which everywhere accompanies the
gold, and which, from its great specific gravity, remains with it in
the bowl or machine after the other earthy materials have been re-
moved, varies in fineness with the size of the accompanying gold ;
that obtained in connection with the fine river gold being of the
fineness of writing sand, while that associated with the coarse gold
of the ravines is often as large as wheat kernels, or peas, and some-
times of the size of hazel nuts or w^alnuts. These coarser pieces are
fragments of crystals very hard and heavy. I found no specimens
with the faces complete, and have not the means of knowing to what
species they belong, but suppose them to be magnetic iron. That the
•fine sand is composed of fragments of the same crystals greatly com-
minuted, I infer from the regular gradation of the one into the other.

I am not aware that the gold has yet been discovered in place, or
ir .bedded in its native matrix. The slates, however, of the gold re-
i;ion, as I have before observed, are often traversed by dykes or beds
of quartz rock, and I have examined these in many places for indica-
iions of the presence of the metal, but could detect no traces of it.
Individuals have asserted that they have found veins of it in the rocks,
but they have refused to divulge the place where, inasmuch as they
intended to work the veins themselves as soon as the season would
permit. Though these statements are of course not impossible nor
indeed improbable, I do not consider the fact as established by tes-
timony, since the witnesses are men in whom I place but little con-
fidence.

The amount of gold taken from these mines it is impossible to

474 Intelligence and Miscellaneous Articles,

estimate, but it has been immense, and the coming season it will
doubtless be greater. New and rich deposits are developing every
day. Accounts from various points in the mining district, represent
the gold as very abundant, more so if possible than last year — indi-
viduals even early in the season obtaining often from three to ten
or even twenty ounces a day. The diggings on the several forks
of the Rio de los Americanos, the Stanislaus, the Tuwalumnes, the
Merced, the Mariposa, King's river (Lake Fork on Fremont's new
map), and in many, other places, are represented as peculiarly rich.

There was one specimen of gold mingled with quartz, found near
Stanislaus last autumn, which I had resolved to procure, if possible,
for the cabinet of Yale. It was irregular in form, about four inches
in diameter, and weighed 5^ pounds avoirdupois. The metal was
interspersed in irregular masses through the stone, and as near as I
could judge without special investigation, was equivalent to about
two pounds troy, perhaps a little more. Other specimens much
larger are said to have been found, and one of twenty pounds
weight pure, near the Stanislaus ; but these I have not seen. — Silli-
man's Journal, November 1849.

COMBINATIONS OF OIL OF TURPENTINE AND WATER.
BY M. H. DEVILLE.

Oil of turpentine and some isomeric compounds have the property
of combining with water, to form substances which well deserve the
name of hydrates, on account of the facility with which this water
may be separated from them. But some singular reactions which
occur entitle them to be regarded as compounds of a very peculiar
order, and which are without analogy in the history of products
of the same kind.

These bodies lose a part of their combined water by the action
of heat or exposure to a dry vacuum, and they regain it by exposure
to a moist atmosphere.

The action of reagents seems to indicate, at least with oil of tur-
pentine, that the hydrate does not contain the primitive oil in
combination. The compound of camphor, obtained by means of hy-
drate of turpentine and hydrochloric acid, is a proof of this. It will
also be seen, that this property has allowed of the conversion of oil of
turpentine into oil of lemons, or at any rate into a substance which
has all its chemical properties and characteristic odour.

It has long been known that the oils of turpentine and lemon
sometimes deposit crystals which, as regards composition, differ from
the oil only by the presence of six equivalents of water. These are
the results to which the only good analyses that have been per-
formed, lead. They are those of MM. Dumas and Peligot, who, in
point of fact, found the formula of the crystalline bodies of oil of
turpentine and cardamom; &c. to be C^o H^^ 0"= 0^° H'^ H*' 0".

Some years since M. Wiggers obsei'ved that in certain veterinary
medicines formed of a mixture of alcohol, nitric acid, and oil of tur-
pentine, there was deposited a considerable quantity of a crystallized

Intelligence and Miscellaneous Articles. 4-75

substance, which possessed the composition of the hydrates analysed
by MM. Dumas and Peligot.

M. Deville continued the researches of M. Wiggers, and found
that, to obtain the hydrate of oil of turpentine in a short time, the
most convenient substances and proportions were, 4 litres of com-
mercial oil of turpentine, 3 litres of alcohol at 85°, and 1 litre of
common nitric acid. At the expiration of a month or six weeks
250 grammes of very pure crystals were obtained, and eventually
more than a kilogramme was gradually deposited. The oils of lemon
and bergamot yield the same results when similarly treated. Oil of
copaiba with nitric alcohol acquires much colour, and after a long
time yields so' small a quantity of crystals, that they could not be
analysed.

If a mixture be made of oil of turpentine and crystallizable acetic
acid, no effect is produced even in several years ; but if a few drops
of nitric acid be added to the mixture, solution takes place in a few
days, and crystals are soon deposited. On putting the liquid in vacuo
over a vessel full of potash, and another full of sulphuric acid, the
vapour of water, of nitric and acetic acids, and of oil of turpentine
is absorbed, and there remains a blackish paste, from which, by means
of alcohol, there may be extracted crystals of the same form and com-
position as those obtained with nitric alcohol.

The action of the nitric acid in the combination of water with the oils
it is very difficult to determine. It is to be remarked that the acid
does not increase the solubility of the oil in the alcohol, but on the
contrary, diminishes it. Neither dilute alcohol, alcohol almost ab-
solute, nor alcohol acidified with nitric acid, had any effect on oil of
turpentine after having been mixed with it for several years. Pure
water and these oils combine, however, though very slowly, and in
small quantity but regularly, in vessels in which the oils are kept
impregnated with moisture. The crystals thus produced, although
possessing the same composition as those deposited from nitric alcohol,
differ considerably from them in form, as will be seen hereafter. It
is also to be remarked, that the hydrate of oil of turpentine, which is
formed in a mixture of acetic and nitric acid, assumes a form which
is sensibly different from that which it has after solution in and cry-
stallization from alcohol.

The author states that he should have been curious to examine
these various compounds which so resemble each other, and which
are perhaps dimorphous and chemically identical. Unfortunately it
is very difficult to procure the hj'^drate formed accidentally in old
oils, that is to say, the product analysed by MM. Dumas and Peligot,
so that all hope of obtaining it in sufficient quantity, even for an
imperfect examination, was relinquished.

Hydrate of oil of turpentine is one of the most beautiful sub-
stances obtainable, on account of its size, perfection, limpidness and
splendour of its crystals, which are right prisms with rectangular
bases.

This substance exerts no action on the plane of polarization ; it
fuses from 217° to 221°, losing a little water; when exposed to a

476 Intelligence and Miscellaneous Articles.

higher temj^erature its composition changes. When it has been
melted it does not perfectly solidify on cooling, but remains soft, and
may be drawn into threads at common temperatures. It is at first
transparent, and then after some time it becomes a mass of radiating
crystals. At 50° Fahr. 100 parts of alcohol of 85° dissolve 14-4a.
Its composition, as well as that of the hydrates of oil of lemon and
bergamot, is as follows : —

Experiment

Carbon 63-2

Hydrogen
Oxygen .,

I.

II.

III.'

63-2

62-9

63-0 Calculation (C20H22O6)

11-7

11-7

11-7

25-1

25-4

25-3

1000 100-0 100-0

When hydrate of oil of turpentine is heated to a higher tempe-
rature than that at which it melts, it is very rapidly decomposed into
•water and a new hydrate, not containing more than two equi-
valents of water, and which almost entirely evaporates ; the residue
is inappreciable.

It will be remembered that MM. Blanchet and Sell have found and
analysed a substance obtained from oil of turpentine, to which they
have assigned the formula C^oH^'H^O'^. In the nomenclature
adapted to these series of compounds, the name of monohydrate of
oil of turpentine ought to be given, as well as to the product derived
from distilling the hydrate obtained from the action of nitric alcohol
on oil of turpentine ; M. Deville gives the name oi perhydrute to the
crystals collected in moist oil of turpentine or treated with nitric
alcohol.

Heat is not the only agent which is capable of converting the ter-
hydrate of oil of turpentine into bihydrate ; the same effect is pro-
duced by a dry vacuum. Moreover, the terhydrate is reproduced,
when, after having lost, by either mode, 2 equivalents of water, it is
left exposed for some time to moist air. This singular reaction is i)ro-
bably unparalleled in organic chemistry : it is surprising to observe
a substance which is totally insoluble in water, like the bihydrate of
oil of turpentine, absorb water from a moist atmosphere, as is shown
by the result of quantitative analyses performed with care.

The following are the results of an analysis of the bihydrate, re-
cently prepared by means of many distillations : —

Experiment. Calculation. (C^^H^^O*)

Carbon 69-4 69*76

Hydrogen ... 11-8 11-63

Oxygen 18-8 18-61

100-0 100-00

The density of the vapour confirmed this formula ; by experiment

it was 6*257, by calculation 6-01 ; the bihydrate possesses no acid

reaction ; when heated with potash, it is volatilized and does not

combine "with it, although its composition would lead to the con-

Intelligence and Miscella7ieous Articles, 4-77

elusion that it would have the properties of a fatty acid ; it boils
fixedly at 282° Fahr. ; it is volatile without residue.

When oil of turpentine is treated with nitric alcohol, another
substance is obtained which may be considered as a liquid hydrate.
After remaining mixed for several years, these substances do not
dissolve, and the oil of turpentine is not entirely metamorphosed. On
heating the viscid and coloured oil which floats on the nitric alcohol
to 428° Fahr., water first comes over, then oil of turpentine, after-
wards a peculiar liquid, into the composition of which, judging from
the results of analysis, the elements of water enter ; it is probably
only impure liquid bihydrate of oil of turpentine ; it yielded by
analysis, —

Carbon 76-4

Hydrogen 11-6

Oxygen 12-0

1000
By analogy it ought to be admitted that a liquid terhydrate can-
not exist at 292° Fahr. If it be supposed that an oil be present in
this product representing a J-quid hydrate, its composition must be,

C'^o 69-8

W 11-6

O* 18-6

100-0
This formula is that of the solid bihydrate of oil of turpentine.

It appears from the above detailed experiments, that oil of tur-
pentine forms with water three very distinct compounds : —

C20H16, H606

C^oH'6, H*0*

C20H16, H'2 02 (Blanchet and Sell).
The two first may be converted into each other at pleasure, since a
dry vacuum takes away 2 equivalents of water from the terhydrate,
and moist air restores 2 equivalents of water to the bihydrate. —
Ann. de Ch. et de Phys. Septembre 1849.

ACTION OF PHOSPHORIC ACID ON THE HYDRATES OF OIL OF
TURPENTINE. BY M. H. DEVILLE.

When the bihydrate or terhydrate of oil of turpentine is treated
with anhydrous phosphoric acid, a colourless oil is obtained, which by
distillation is separated into two other oils of different volatility : one
is tereben, easily recognized by its odour, fluidity and composition.
It gave by analysis —

Experiment. Calculation. (C^H'")

Carbon 88-1 88-24

Hydrogen 11-9 11-76

1000 100-00

The other oil is viscid, boils at a higher temperature, and is more
dense than the above ; it possesses characteristic dichroism, sometimes
appearing blue and at other times colourless : it is colophen.

478 Intelligence and Miscellaneous Articles.

Analysis gave —

Experiment. Calculation. (C^OR^)

Carbon 88-1 81-24

Hydrogen ITS 11-76

99-9 100-00

Oil of turpentine acts exactly in the same way with anhydrous phos-
phoric acid as the hydrates, being like them converted into tereben
and colophen. — Ann. de Ch. et de Phys,, Septembre 1849.

ON THE INFLUENCE OF BORACIC ACID ON VITRIFICATION.

M. Maes, manufacturer of flint-glass^ has, conjointly with M. Cle-
mandot, long paid attention to the above-named subject. The prin-
cipal results hitherto obtained are : — 1st, borosilicate of potash and
lime ; 2ndly, borosilicate of potash and zinc ; 3rdly, borosilicate of
potash and barytes ; 4thly, borosilicate of soda and zinc.

The borosilicate of potash and lime was formed with the intention
of producing in close vessels with coal furnaces, the best imitations
of Bohemian glass. In the Compte Rendu de V Exposition AutricM-
enne, 1845, published by M. Peligot, it appears, that in order to
make the purest and most durable glass in 13ohemia, they use with
100 parts of silica, 12 parts of unslaked lime, and only 28 parts of
carbonate of potash. From this we must conclude that the glass is
better the less potash and the more lime it contains.

The above proportions yield a glass which is infusible in the fur-
naces employed by M, Maes. The addition of a few hundredths
of boracic acid is sufficient to occasion fusion, and the resulting pro-
duct possesses all the limpidity, splendour and hardness which can
be desired.

This first experiment naturally suggested the advantage which
might be derived from the solvent power of boracic acid so as to in-
troduce bases into glass which had not hitherto been employed, as
borosilicate of potash and zinc, and that of potash and barytes. The
borosilicate of potash and zinc appeared to impart all the qualities of
a pure and durable glass. As to the borosilicate of potash and ba-
rytes, it was prepared from native carbonate of barytes, contaminated
with sulphate of barytes and a ferruginous gangue. If then it be less
colourless than the zinc glass, the colour is certainly accidental : on
again making it with pure carbonate, this imperfection would un-
questionably disappear.

The beauty of borosilicate of potash and zinc led to the compara-
tive trial of borosihcate of soda and zinc : this, although inferior to
the potash, incontestably excelled all the soda glasses compared
with it.

To recapitulate : the borosilicates are chiefly remarkable for their
transparency and hardness. They derive these important qualities
from reducing considerably the potash and soda which almost always
are in excess in common glass; and every one knows that glass
"which is too alkaline, is cloudy, soft and hygrometric.

Meteorological Observations, 479

These observations, in the opinion of the author, warrant the con-
clusion, that boracic acid must before long contribute to the perfec-
tion of glass for optical purposes, and M. Maes proposes to prepare
borosilicates of great density, with lead, bismuth, &c., besides ba-
rytas.— Comptes Rendus, Oct. 22, 1849.

METEORS.

On the 24th, about 8^ p.m., I saw two fine meteors in a north-east
direction, one about ten minutes after the other. The former seemed
to burst like a sky-rocket and fall a little way ; the latter to shoot in
a north direction and fall to the horizon in pieces of blue colour.
On the 30th, a little before 7 p.m., a very splendid one was seen in
this parish and also in Kirkwall, which is nearly twenty miles off.
Here it appeared first near the zenith and travelled westward. —
Rev. C. Clouston, Sandwich Manse, Orkney.

METEOROLOGICAL OBSERVATIONS FOR OCT. 1849.

Chhwick. — October 1. Drizzly : OTercast. 2. Cloudy. 3. Constant heavy rain.

4. Heavy rain in the morning : showery. 5. Clear : fine : overcast. 6. Fine :
rain at night. 7. Hazy : cloudy : rain. 8. Cloudy and cold : clear : blight frost
at night. 9. Clear : very fine : frosty at night. 10. Dense fog : very fine : clear.
11. Cloudy : clear. 12. Cloudy and cold : clear. 13. Rain. 14. Cloudy and
cold. 15. Fine : clear at night. 16. Foggy : hazy : overcast. 17. Cloudy and
fine. 18. Very fine : clear at night. 19. Slight fog: exceedingly fine : clear.
20. Very fine. 21. Hazy : clouds : rain. 22. Foggy: fine. 23. Cloudy and
fine. 24. Overcast : fine. 25. Showery. 26. Cloudy. 27. Drizzly. 28, Over-
cast: very fine. 29. Foggy : exceedingly fine. 30,31. Very fine.

Mean temperature of the month 49°'58

Mean temperature of Oct. 1848 49 '59

Mean temperature of Oct. for the last twenty-three years 50 "51

Average amount of rain in Octoher 2*58 inches.

ApplegarUi Manse, Dumfries-shire. — Oct. 1. Fair, but damp and raw. 2. Frost,
hard : clear and fine. 3. Frost : rain p.m. : snow on the hills. 4. Frost a.m.

5, Frost A.M. : shower P.M. 6. Frost still harder : thermometer 24^°, 7. Frost
milder: windhigh. 8. Cold, but little frost : fine. 9. Frost hard again : shower p.m.
10. Frost hard : fine day. 11. Frost slight : a few drops. 12 — 14. Frost slight :
clear and fine. 15. Frost : cloudy. 16. Little or no frost : cloudy. 17. F'rost
hard again: rain p.m. 18. Mild: rain: cleared p.m. 19. Mild: cloudy:
threatening rain. 20. Fair: variable : high wind p.m. 21. Showers, but mild.
22. Slight frost A.M. : heavy rain p.m. 23. Mild: rain during night : rain p.m.
24. Rain all day : flood. 25. Rain all day : fog : flood. 26. Fine : one shower:
cleared. 27. Rain again : thick weather. 28. Fine: clear. 29. Frost a.m. :
fine : cloudy p.m. 30. Dark and cloudy : rain p.m. 31. Showery all day ; mild.

Mean temperature of the month 44°'0

Mean temperature of Oct. 1848 46 '5

Mean temperature of Oct. for the last twenty-five years ... 46 '6

Mean rain in October 3*25 inches.

Rain, number of days in which it fell, 15. Average rain

in Oct. for twenty years 356 „

Sandwiclc Manse, Orkney. — Oct. 1. Bright: hail-showers. 2. Sleet-showers.
3. Clear : frost. 4. Siiowers : clear : frost. 5. Clear : showers. 6. Bright :
clear: frost. 7. Clear: aurora. 8. Clear: showers. 9. Sleet-showers: clear.
10. Fine : very clear : aurora. 11. Frost : fine : very clear : aurora. 12. Fine:
very clear. 13. Cloudy: aurora. 14. Bright: clear: aurora. 15. Showers.
16. Cloudy. 17. Bright: showers: cloudy. 18. Drizzle : cloudy. 19. Bright:
showers ; cloudy. 20. Showers : cloudy. 21. Cloudy : showers. 22. Cloudy:
fine : showers. 23. Showers : clear : aurora. 24. Fine : aurora. 25. Rain :
fine : aurora. 26. Showers : clear. 27. Bright : showers. 28. Bright : showers ;
clear, 2P. Rain; cloudy, 30, Cloudy; showers ; aurora. 31. Bright; fine,

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THE
LONDON, EDINBURGH and DUBLIN

PHILOSOPHICAL MAGAZINE

AND

JOURNAL OF SCIENCE.

SUPPLEMENT to VOL. XXXV. THIRD SERIES.

LVIII. On the Rotation of the Plane of Polarization of Heat
by Magnetism, By MM. F. de la Provostaye and P.
Desains*.

SHORTLY after the brilliant discovery of Prof. Faraday
of the rotation of the plane of polarization of light by
magnetism, M. Wartmann announced f that he had tried the
same experiment with radiant heat. He employed the heat
of a lamp, which he partially polarized by making it pass
through two piles of mica crossed at right angles. The elec-
tro-magnets and a cylinder of rock-salt were placed between
these piles, and consequently very near the thermo-electric
apparatus. The galvanometer, on the contrary, to be pre-
served from the action of the electro-magnets, was removed
to a great distance ; but the result was a considerable increase
in the length of the circuit, and a diminution of sensitiveness.

Notwithstanding all these inconveniences, which he clearly
pointed out, and which he was not able to overcome, M. Wart-
mann thought he observed that the needle of the galvanometer,
after having attained a fixed deviation under the influence of
the radiation not intercepted by the piles of mica, was again
displaced and took a fixed position different from the first*
when the current was established, which seemed to indicate a
rotation of the plane of polarization of heat.

At Paris, some persons having vainly attempted to repro-
duce these phaenomena, we have considered that it would
be useful to revert to these experiments, and to point out a
method which permits of making them succeed with facility.

We have introduced into M. Wartmann's process three prin-
cipal modifications: — 1st, we employ solar heat; 2ndly, we take
for polarizing apparatus two prisms of achromatic spar; Srdly,
and this appears to us indispensable, instead of placing the
principal sections at 90% we arrange them so that they make
an angle of nearly 4-5°.

* From the Annates de Chimie et de Physique, October 1849.
t Institut, May 6th, 1846, No. 644.

Phil. Mag. S. 3. No. 239. Suppl, Vol. .35. 2 I

482 On the Rotation of the Plane of

The employment of spars and solai' light permits of re-
moving the electro-magnets to a great distance from the
ihernio-electric pile. With respect to the arrangement of
the prisms, the law of Malus shows all the advantages which
it presents. In fact, let us take for unity the deviation wliich
the solar ray transmitted through the principal parallel sec-
tions would produce. The deviation, when the prisms form

an ancle of 45°, will be cos^45°=— -. If the current is set in

action, and it produces a rotation of the plane of polarization
equal to 8, the deviation will be, according to the direction of
the current, cos^(45°— 8) or cos^(45°-fS), and we shall then
have, for the difference of the effects observed when the cur-
rent is made to pass in a contrary direction,

cos2(45°-8)-cos2(45° + 8) = sin28.
On placing the principal sections at 90^^', the difference of
the deviations would be only

cos2(90°-8) - cos2 90''= sin^ 8,
or

cos2(90° + 8) - cos290''= sin^S.

Now sin^8 is considerably less than sin 2^. If, for example,
we suppose 8=8°, sin 28 is equal to more than fourteen times
sin 28.

The eye, it is true, appreciates readily the transition from
darkness to light, but not so the difference in brightness of
two luminous images. This is not the case with the ihermo-
scopic apparatus. There is therefore, when heat is concerned,
a great advantage in proceeding as above directed.

The following are the details of the experiment: the solar
ray, reflected by a heliostat, traverses at first a doubly re-
fracting achromatic prism. The extraordinary bundle was
intercepted : the ordinary bundle traverses the electro-magnet
of M. RuhmkorfF'sapparatus,and aflint-glass ofSSmillimetres
in thickness between the poles of the electro-magnet. It after-
wards encounters, at about S'^'SO, the second prism of spar,
bifurcates again, and gives two images, one of which may be
received on the thermo-electric pile placed at four metres from
the electro- magnet. The galvanometer was still a little further
removed from this disturbing force. It was ascertained, by
direct and repeated experiments, that on establishing the cur-
rent there were no phsenomena of induction, and that the
electro-magnets had no appreciable action on the magnetic
needle which, under their influence, remained at zero in a state
of perfect rest. In order to understand this, it must be borne
in mind that the two opposite poles are very close together,

Polarization of Heat by Magnetism. 483

and that they act simultaneously upon a system already very
distant and almost completely astatic. It might be feared that
the electro-magnet, without action on the needle at zero, acted
on the needle already displaced by the action of the calorific
radiation. This would be possible in fact, if, in its first po-
sition, the needle had the same direction as the line which
joins its centre to the electro-magnet, and if, when it deviates,
it made a notable angle with that direction. In our experi-
ments, precisely the inverse condition was realized ; so that
the component of the magnetic action diminished more and
more during the movement of the needle, and became per-
ceptibly null when it attained its greatest deviation. If there-
fore it had no action in the first case, such ought for a stronger
reason to be the case in the second.

By means of a commutator the electric current could be
made to pass, now in one direction, now in another, through
the wires of the electric magnet. We shall designate the two
currents by the abridged expressions Current A, Current B.

The following are the deviations observed : —

Experiments of September 22.
(A Muncke's battery of 50 elements with large surfaces, but
already worn, was employed.) •

First Series.

Deviations.

Current A 21-0

Without current . . . 19*0

Current A 21 '4

Without current . . r 18*6

Second Series.

(Acid was added.)

Without current . . . 20*5

Without current . . . 20*6

Current B 18-6

Without current . . . 20-9

Current A 23-6

Current B 18'8

Current A 22-0

Current B 18 0

Without current . . . 19*9

Third Series.

Current B 1 7*4

Currents IT'l

Current A 19-5

Without current . . . 18-3
2 I 2

484 Prof. B. Silliman on a Granular Alhite

Experiments of September 29.

(A Bunsen's battery of 30 elements, well-cleaned and amal-
gamated, was employed.)

First Series.

Without current
Current A . .
Current B . .

Without current
Current B . .
Without current

Deviations.

12-0

14-9

8-6

11-7

8-8

11-8

Second Series.

Without current . . . 18*4

Current B 14-9

Current A 21-7

It is to be remarked, that here, if the principal sections of the
prisms were perpendicular, the deviation, at first null, would
scarcely attain one semi-division when one of the currents was
made to act.

Lastly, to obviate every objection, a third series of experi-
ments was made by taking away the prism of flint-glass, and
observing the deviations produced by the solar ray, when, as
before, the electric current was made to pass in the wires of
the electro-magnet, now in one direction, now in another.

Devia-^ As should be the case, the deviations are
tions. I equal, which proves that the electric cur-
Current A ... 16*5 Vrent and the magnet change the devia-
Current B ... 16*8 tions in acting on the flint-glass and not in
Current A ... 16"8 J acting on the needle of the galvanometer.

The above experiments establish, we believe, in an irre-
fragable manner, the rotation of the plane of polarization of
heat under the influence of magnetism.

LIX. On a Granular Albite associated xvith Corundum, and
on the Indianife ofBournon. By B, Silliman, Jun., M.D.,
Professor of Chemistry applied to the ^rts in Yale College,
and of Medical Chemistry and Toxicology in Louisville Uni-
versity, Kentucky^.

A SPECIMEN of a granular mineral was sent me by
Mr. Gibbs of Andover, last year, with the remark that it
was found in beds in Lancaster County, Pennsylvania, and

• From Silliman's Journal for November 1849.

associated with Coru?idum. 485

was so hard as to resist all attempts to penetrate it by hardened
steel, greatly impeding the operations of the miners in the
chrome iron districts.

I also received other specimens of the same from Mr. Wil-
liams of Westchester, associated with corundum, which was
found imbedded in it; and from this circumstance it has been
mistaken by some mineralogists for Indianite, which species
it resembles in hardness, gravity and in granular structure,
but not at all in composition.

In its granular structure it so resembles dolomite, that no
difference can be detected between them by the eye, while
its hardness and great difficulty of fracture completely blind
the inquirer as to its real character. Its characters are as
follows : —

Massive, compact, granular, resembling while dolomite ;
tough ; fracture even, but very difficult. Colour, white with
shades of gray. Streak, white. Hardness, 7 to 7*25 (scratching
quartz with facility). Gravity, 2-619.

Insoluble in acids. Before the blowpipe, infusible, and
does not colour theJlamei/eUoiso ; with the fluxes yields evidence
of silica, alumina and lime. By a quantitative fusion with
carbonate of baryta, soda was detected.

The first specimen analysed was from Lancaster County,
Pennsylvania, and showed no trace of corundum disseminated
in it.

This analysis was made by Mr. G. J. Brush, and yielded
on the quantity taken, 1-234- grm., as follows: —

Oxvgen.
Silica .... 0-8225 = 66-653 p. c. 34-85=12
Alumina . . . 0-2565 20-786 10-70 3

Lime .... 0*0253 2-050]
Magnesia . . . 00071 0-519 V 3*08 1
Soda . . . . 0-1155 9-360 J

1-2269 99-420

It gives the constitution 4SiO^ AP 0^
+ NaO, SiO^:—

NaO=

:AP

03,SiCF

4 atoms
1 atom
1 atom

Silica .
Alumina
Soda .

. 2309-24
642-33
390-90

69-09
19-22
11-69

per

cent.

•

3242-47 100-00

This is precisely the formula and constitution of an albite.
The second analysis was on a specimen from Unionville,
Chester County, Pennsylvania, having identical characters,

486 On a Granular Albite associated with Corundum.

but associated with corundum, which occurs implanted in it.
This analysis was made by Mr. M. C. Weld. Quantity
taken,2-180 grms. Found —

Oxyjjen.

Silica , .

. 1-4575 =

= 66-857 p. c.

= 12

Alumina .

. 0-4772

21-889

3

Lime . .

. 0-0389

1-785'

Magnesia .

. 0-0105

0-481 Y

1

Soda . .

. 0-1914

8-779

Water

. 0-0105

0-481

2-1860 100-272

This obviously yields the same formula as the last analysis.

The extreme hardness of this mineral is its most remarkable
quality, and is not easily accounted for. It is probably con-
nected with its association with corundum, for we find the
quality equally developed in the Indianite (or anorthite), the
Asiatic associate of the same species.

Analysis of Indianite. — I thought it of interest, in connexion
with the foregoing analyses, to make a new analysis of Bour-
non's Indianite, which, as already remarked, is found to be
the matrix of the corundum in India. Being possessed of an
authentic specimen, I requested Mr. Brush to conduct the
analysis, the results of which are now given. This mineral is
granular, and of a pink colour, sometimes gray or blackish;
very tough and hard. Hardness, 7 to 7-25. Gravity, 2-668.
It gelatinized completely in cold hydrochloric acid. Before
the blowpipe alone, infusible. The analysis gave on 1-594
grm.—

Silica . . .
Alumina and a
trace of iron
Lime . . .
Soda . .

1-6077 100-84
4Si08, R2 0% sR0 = 3R0, Si03 + 3(R2 O^ SiO^),
which is the formula for anorthite.

0-6710 =

4209 p. c.

Oxygen.
21-869 =

= 4

1 0-6200

38-89

17-160

3

0-2516
0-0651

15-78 4-449\
408 1-043J

5-592

1

[ *87 ]

LX. Supplementary Considerations to Mr. S. M. Orach's
Epicyclical Papers (Phil. Mag. June to July 1849)*.

SINCE publishing my above-mentioned papers, I have
unsuccessfully tried the general solution for more than
two circles. However, knowing <p, the polycircloid
3S—^{a^ cos g.f + b. cos;?.^ = X.= R. cos ©.),
j/=S(a.sin g'.(p + 6.sin;?.<p = Y. = R.sin @.),

may be regarded as the ultimate locus of a series of bicircloids,
the centre of each being on the curve o( its immediate prede-
cessor, beginning with the centre of the deferent. With an
odd value of/, one ^^=0, and this last becomes a circle.
We have also

w=Xa^cos{q^(^ + t)i y = Xa^%m {q.<p-ht)y
giving

r^ = 2a? + 2Xa.aj cos q.(p — q.fy

independent of the common constant t.

r = l,a.cos{q.<p + l — Q), 0 = Xa^sin{q.ip-{-t—$).

If the cos angles in r^ naturally arrange themselves as the
powers of cos \J/= cos p(p — (j<p, so that cos ^ is extractible by
quadratic, cubic, or biquadratic equations, the solution is
always analytically possible; e. g. the tricircloid

x=a cos qf + bcospf +fcostf, y— a sin qtp-^-b sin p^ +y sin tf,

.'. 7-2=a2.|_^2_|_y^_,_ 2abcosp — g(p + 2afcosg—t(p + 2bfcosp — i<p'
Let

.'.r^ = a^+{b~ff + 2ab + 2bf cos i> + 4bf cos- 4>,

.'. 4:bf cos ^=—ab-a/± \^ ^bjr^ + {a^-^bf){b-ff.
And then

2r^cosA9={a(c + 5)'?^ + &c.}^+{«(c-s)'?^ + &c.}^
X{K-l),.{K-i+\) i{i-l)..{i-j+l)
1.2..i 1 . 2 . . J

rrp;^(>- 0?^ +('-iW +j*^ = (' - ^•''+'')^ + (c - 5)(^ - -•^'+ '^^

= 2 cos {q — 2j + i)^}.
Substituting the powers of 2 cos xj/ in 2 cos {q — 2j+ #, we get
the general equation of the curve.

* Comnuuiicaled by the Author.

488 Mr. S. M. Drach's Supplementary Considerations
Ex. p—Si q—% ^=1, gives

85 cos^ rj/ 4- 4« cos2\[/ + (5 — 3/)2 cos vp — 2a = 2t,

Wn6IlC6

^bpx = {Sb+f)af{h'^-bf-r^)-a%{b-f)

± [a'^b +fr^ - bj- bp) \^^bfr'' + {a^ - ^bf) [b -ff

for the equation : \^ b^f,

2/2^ + 2ar2 = + (a V - 2/ V + r^) ;

ifa = 2/2 = 2i^

r^- {a^x + 2aa72)2 = (^2 _,_^2)3,

But in these quadratics we have a circumstance analogous
to the discussion of the equations of the second order. For
that cos xp be real, the v^~ must cover a positive quantity or
zero; which, when b andyhave different signs, shows that
^bf[r'^-{b-ff] must be ^{ab-afY; whena2=4/^/,

« cos \p = — 6 — /■+ r.

Similarly, j9 = 3g— 2/, p-=^q — M would lead to a cubic or
biquadratic equation. Even higher powers are thus resolvable,
if the intermediate powers disappear through their coefficients
vanishing, as

cos^^ij, -f 2Ai cos^vl/ = A2
gives

cosrI/=-^(-Ai± v^Ai^+Aa).

The above tricircloidal expansion of 2r^ cos a9 exists what-
ever \ be assumed to be, and for cos we may write sin on each
side of the equation.

The straight-lined, curved-cornered bicircloids, cos nQ =
funct. (r), are true regular bicircloidal polygons qfn sides, cor-
responding to the angular ones of the simple circle (Euc.
book iv.).

For the central bicircloids,

P — Q «
r=2acos^^ — —L
p + q

f^H ,.-. I ,-.-,.-. , ^.JdU\r-^)-dHd{r-^)\df

becomes

S{p—q)hi^r~^ + ^pqr~^i

.'. when q — 0 (excentric circle), as r"^ (Princ. I. vii. 1).
The length of these central bicircloids

= 2afdWy—'^pq{p + q)-^sm^{p-\-q)[p — q)-%

an elliptic integral, except when §'=0, =2a^ (see fig. Euc. i. 1).

to his Epicyclical Papers. 489

The loops of these curves are in general not analytically

identical with the lemnoid resembling >0, where q — 2,p = S,

For in the other loops (wn'=l) R^^'a^ gives

{2^664^-2 + &c}'''=2X"'"''-R2(«'+ 1)(2X)»+' &c. ;

so that X does not =X generally.

The radius of curvature of the syphonoid

(a?=a cos qfy y=- cosp<p)

{(fia'-x'^) -^p\b'^-f)]^-^{p^qy Va^-x^-q^px x ^6^-^},
and its area

fydx = (p \/ (a2-a?2)(62-y) + qxy^ ^{q^ -p^) .

For the lemnoid

(a:=a cos 5'(p, y—y'—bs\x\p(p)

change +g to —q in these two expressions. Their arc-
lengths are

/' / sin^

dfy « V sin^ qf + b^ ^^^9. p<p

respectively.

The following table gives some results at critical points.

X.

y-

y'.

Rad. curvature.

Area.

Syphon.

Lemnoid.

Syphonoid.

Lemnoid.

a
a
0
0

b
0

b

0

0

b

0
b

0-^0
p^-^ba-'

OH-0

00

p^q-'^ba-^

CO

0^0

qab{q^-p^)-'

0
pab{if—p^)~^

0

0

qab{q^-p^)-'

0
pab{q^—p^)~^

Thus for the common parabola,

- abi - ab
3 3

are the respective quantities (the latter for half the area at the
axis). Thus every lemnoid corresponds to a syphonoid.

The paragraphs in the Literary Gazette for March 28,
1846, were not penned by me, who had just made Mr. Perigal's
acquaintance. Subsequent investigations have shown me that
this Kinematic Parabola, being a finite portion of the common

490 Mr. R. Phillips on Electricity and Steam.

conical one, has its x and y dependent on the periodic cos ju. ;
which quantity enters explicitly and implicitly in the differen-
tial expression for the centripetal force to the focus, which is
therefore uot identical with the Newtonian law.

S. M. Drach.
November 26, 1849.

LXI. On Electricity and Steam. i?j/ Reuben Phillips, £.sy.*

35. ^T^HIS paper is a continuation of a former one (Phil.
A Mag., vol. xxxiv. p. 502), wherein are described
some magnetic actions produced by steam in the act of con-
densation. 1 regarded those motions as the effect of dynamic
electricity, and then endeavoured to obtain the static effect,
which I think I have done.

36. An electrometer was constructed in the following man-
ner:— A straight slip of thin metal, about '4 inch wide, was
bent at some distance from one end, the direction of the mo-
tion in bending being in a plane perpendicular to the original
surface of the plate and parallel to its length, and the bending
was continued until the included angle was 0; the bend was
opened a little, the end of a slip of gold-leaf inserted, and the
whole rendered secure with a binding-screw. Previously,
however, the plate at that part which was close to the end
that had been doubled in, had been bent in the same direction
as before, four times at right angles, so as to leave a little pro-
jection across the plate, over which the gold-leaf hung; the
object being to keep the gold-leaf so far from the metal plate,
that a rapid inspection sufficed to show that the former was
free to move. The gold was the length of one side of the
usual gold-leaf, and the metal plate extended parallel with it
to its lower end. The doubled portion was now fitted into a
slit in a cork, which was then inserted into a glass tube, the
end of the bent portion projecting about | inch beyond the
external end of the cork. The other end of the glass tube
also held a coi'k, through which a straight metal plate passed
extending parallel to the gold-leaf. The tube was about -9
inch diameter and 5^ inches long, and the ends were covered
with sealing-wax; however, care was always taken to connect
the plate of the lower cork with the earth. The whole could
be supported on a small wooden stand.

37. A singular appearance, but not connected with elec-
tricity, is presented by this electrometer when either of the
metal plates is made to vibrate, as by a slight tap ; for the

* Communicated by the Author.

Mr. R. Phillips on Eledricittf and Steam. 491

gold-leaf is then powerfully attracted by, and drawn into con-
tact with the vibrating plate. I suppose this observation is
new, and very significant with regard to theories of attraction
and repulsion, although I have not pursued it further.

38. As this electrometer was very sensitive, I more gene-
rally employed another, with two short gold leaves, and which
was very far from being a sensitive instrument. This instru-
ment was always employed except where I have mentioned
that the single-leaf electrometer was used.

39. Throughout these experiments the steam was at 40 lbs.
on the inch, and was supplied from the same little boiler and
discharged horizontally as before (7.).

40. The Armstrong's condenser was removed, and the brass
jet (9.) was united to the cock of the boiler by two short brass
connecting pieces. This brass jet originally belonged to an
oxyhydrogen blowpipe, and its shape was slender and conical,
and the small hole at the end of the jet from which the steam
escaped was \ inch long, the remaining portion of the bore
was ^ inch diameter. The boiler communicated with the
electrometer by means of a wire. When the cock was opened,
the boiler became negative.

41. In order to collect the electricity of the steam, I used a
piece of wire-gauze, insulated and supported on a stand, and
which by means of a wire could be made to impart its elec-
tricity to the electrometer; the extent of one side of the piece
of wire-gauze was about 2*5 square inches. The electricity
of the steam was thus found to be positive.

42. A straight glass tube about 3 feet long and '4 inch dia-
meter, was placed horizontally with the brass jet projecting
into it to the extent of the jth of an inch; the tube was also
supported so that an annular space existed between the end
of the jet and the tube. In order to ascertain the electrical
state of the inside of this, or any other tube, a few inches of
its length were covered externally with a piece of tin-foil and
bound on with wire, the other end of which could be taken
to the electrometer.

43. When the steam was turned on, the tube and boiler
both became negative. A connexion existed between the tube
and the boiler; for when the leaves of the electrometer were
divergent, touching the boiler made them collapse. Some-
times the first action of the steam was to make the leaves di-
verge to a small extent, then to make them approximate a
little, and then to cause them to open much more with a ne-
gative charge; but when the connexion between the tube and
the electrometer was broken before the approximation took
place, the instrument was found to be positively charged.

492 Mr. R. Phillips on Elechncity and Steam.

The wire-gauze being placed in the steam as it issued from
the end of the glass tube showed that it was positive.

44. A glass tube, 3 feet 10 inches long and I'l inch dia-
meter, was substituted for the former tube. With this tube
all the foregoing effects were observed, but they were more
powerful.

45. These experiments are only exhibitions of frictional
electricity ; and the different states of the tube are principally
produced by the tube taking its charge, either from the brass
jet or from the excited steam that issued from it.

46. The Armstrong's condenser was now interposed, with
water in it, between the boiler and the brass jet ; and the
smaller tube (42.) had the end which came to the brass jet
fitted with a good cork, through which the brass jet passed and
projected into the tube much as before ; the joint was then made
tight with caoutchouc and thread. To ascertain the state of
the steam, I employed a piece of wire gauze, 6^ inches by 4
inches, attached by means of stout wire to an insulating handle,
by which the gauze could be held in the steam and then
taken to an electrometer. This wire-gauze collector was
generally used in the following experiments.

47. The steam being turned on, the tube and boiler became
positive. When the wire-gauze was held at about an inch or
two from the end of the tube, it took from the steam a nega-
tive charge; and at the distance of something more than a
foot, the gauze also acquired a negative charge which affected
the single-leaf electrometer; and at intermediate positions the
charge was still negative.

48. When the condenser was removed, and the jet was
screwed into the cock of the boiler, everything else being as
before (46.), no decided electrical effects were observed ; but
when the glass tube was also removed, then, having connected
the boiler with the single-leaf electrometer and cautiously
turning the cock, it was discovered that at a particular pres-
sure the boiler became positive, and at much higher or lower
pressures negative.

49. Now I regard these electrical effects as frictional, and
possibly similar to those alternations in the electrical state of
the boiler observed by Mr. Armstrong. (Phil. Mag. vol. xxiii.
p. 202.)

50. While the steam was escaping into the air from the
brass jet as above, I made some attempts to ascertain whether
the steam was positive or negative ; the electricity was very
feeble, on which account I did not care much about it, but the
little that I obtained was decidedly positive. This may have
arisen, although it is improbable, from the boiler becoming

Mr. R. Phillips on Electricity and Steam, 493

negative, but it is more likely that the steam was rendered
feebly positive from a cause which I now proceed to mention.

51. The condenser and jet were arranged as in the experi-
ment (46.), and the smaller glass tube instead of being fastened
on with cork and India rubber stood before the jet as formerly
(42.). The steam being now turned on, the boiler and tube
became positive. When the wire-gauze was about 1 inch
from that end of the glass tube from which the steam was
escaping, it took a negative charge; but at the distance of
about a foot, the larger wire-gauze collector being employed,
the steam communicated a powerful positive charge to the
single-leaf electrometer. The electricity of the boiler and tube,
and the positive electricity of the steam, were much stronger
than the positive and negative electricities of the preceding
experiment with a tight joint between the tube and jet. The
negative charge was most probably given to the gauze by
the friction occasioned by the violent rush of steam and air
against it.

52. The larger glass tube (44.) was put in the place of the
foregoing and carefully adjusted like the former tube, so that
the central line of the path of the steam should lie as nearly
as possible in the axis of the tube. The boiler and tube were
positive. A connexion existed between the tube and boiler,
for when the steam was passing and the leaves of the electro-
meter were greatly divergent, touching the boiler made them
collapse to a comparatively small amount. When the gauze
collector was held at about an inch from the end of the tube,
a positive charge was obtained, and at a distance of 9 inches
a powerful positive charge was still obtained; further experi-
ments in this direction were prevented by a wall.

53. By means of India rubber, the end of the glass tube at
the brass jet was closed, which caused the electrical effects to
diminish to such an extent that the single-leaf electrometer
indicated but doubtful traces from either the tube or steam.

54. A short glass tube, 14 inches long and of the same
bore as the preceding, was substituted for it. The tube was
always positive, and the boiler, except in one instance, neutral
or positive. The larger collector being held, from that end
of the tube from which the steam was escaping, at distances
varying from 1 inch to 2 feet 6 inches, gave always a powerful
positive charge.

55. The glass tube was now removed and the larger col-
lector held in the steam at about 9 inches from the end of
the brass jet; the boiler, collector and electrometer being
electrically united. An abundance of positive electricity was
obtained, which would doubtless have been obtained at a
much greater distance.

494 Mr. R. Phillijjs on Electricity and Steam.

56. The piece of a gun -barrel (20.) was now placed with
proper precautions before the jet, and by means of wire con-
nected with the boiler. The boiler was positive, and the
steam powerfully positive even at a distance from the jet of
4 leet 3 inches, the current of air at that distance being a
mere breeze; and I doubt not that had it not been for the
wall, I could easily have obtained plus electricity at double
the distance. From this it clearly follows that the plus elec-
tricity of the steam cannot be generated by friction against
tlie gauze. Neither does friction in the tube generate it, for
the effect was obtained without a tube (55.); nor can it be
generated by friction in the brass jet, for this frictional elec-
tricity was found to leave the boiler negative, which negative
electricity was not nearly equivalent to the positive of the
steam (55.); to which I may add the similar experiments with
the tubes, the tubes being evidently collectors only and not
generators of the electricity of the steam.

57. It would seem as though positive electricity only, with-
out negative, was generated in these experiments; however, it
is not so.

58. The single-leaf electrometer was now placed in the vial-
holder of a microscope, through which the motions of the gold-
leaf were observed by a power of about 200 tliameters, a micro-
meter eye-piece being employed. Also a thin piece of metal,
2 inches by 6 inches, was fixed on an insulated support, the
greater length of the plate being about perpendicular to the
horizon. This metal plate was now placed at a little distance
from the end of the former gun-barrel arrangement [56.)^ and
sufficiently distant from the path of the steam to be out of the
way of the straggling drops of water ; this screen was now con-
nected with the electrometer, and the boiler carefully connected
with the earth. When the steam was turned on, the electro-
meter received a negative charge. The extent of the motion of
the leaf was very variable, depending, 1 think, on the amount
of water discharged with the steam; on the average, I reckoned
it about five micrometrical divisions. A brass tube, 6 inches
long and ^^ inch diameter, was now janmied on the end of
the gun-barrel, to increase its length, and the inducteous
plate was placed at the end of it, as before at the end of the
gun-barrel. The steam now being turned on, the leaf moved
over between twenty and thirty divisions.

59. it was easy to become convinced that these motions of
the leaf were really produced by induction, by turning on the
steam and allowing the leaf to obtain its deviation and then
quickly shutting off" the steam, when the leaf would promptly
fall back. Also with the brass tube on, I managed to charge
the instrument positively by turning on the steam, then open-

Mr. R. Phillips on Electricity and Steam. 495

ing a communication for a moment between the earth and the
plate, and then shutting off the steam.

60. When the brass tube was on the end of the gun-barrel,
the leaf seldom returned to its starting-point when the current
of steam was stopped, and the instrument appeared to have ac-
quired a permanent charge, which was negative, and appeared
to go on increasing with the time that the steam was allowed
to escape. It was found, too, that as the inducleous plate was
removed in a direction perpendicular to the path of the steam,
the first-mentioned effect of induction rapidly diminished, but
that the power which appeared to give the permanent charge
scarcely underwent any alteration, even when the distance from
the path of the steam was increased to 9 inches, the greatest
distance the apparatus would allow. I have but little doubt
that this apparently permanent charge was principally pro-
duced by the inductric action of the steam-cloud.

61. From the foregoing it is seen that the jet of steam im-
parts positive electricity to any substance that it touches, while
at the same time the steam, as a whole, may be more or less
negative. These facts will very well comport with the idea
that the particles of water are positive and the gaseous matter
negative; hence when the current passes through a tube or
touches a piece of wire-gauze, the particles of water become
more or less separated from the air and vapour, leaving them
negative. That the negative electricity of the gaseous matter
is not immediately transferred to the particles of water, is, I
suppose, due to the non-conducting power of gases.

62. When these electric effects are being produced by the
jet of steam, a peculiar rough sound is heard, which is de-
pendent on the tlischarge of water with the steam; for when
the jet was screwed into the cock of the boiler, I never heard
any other sound than a smooth sibilation; and when water
was discharged with the steam, if its quantity was not qiute
sufficient, the smooth hiss only was obtained. At such times,
the steam, as it issued from the jet, on being examined, was
found to be, for the distance of -^-th of an inch from the end of
the jet, transparent, with the exception of a thread-like appear-
ance of cloud extending through the clear steam parallel to its
path. Presently, from a lowering of the pressure, or other
cause, this little cloud expanded all round the jet, and then
looked like a frustum of a little right cone of cloud stuck on
the end of the brass jet, the roar being at the same time per-
fectly developed. These effects were obtained without any
tube before the jet.

63. With the arrangement described (51.) very instructive
results were occasionally obtained; the tube was connected

4f96 Mr. R. Phillips on Electricity and Steam.

with the electrometer. Sometimes, when the steam was turned
on, the roar was absent, and then the electrometer was with
difficulty acted on ; then suddenly the roar was set up, and
the electrometer was promptly and powerfully affected.

64-. It appears to me that when water is discharged with
the steam and a smooth sibilant sound only obtained, that the
water passes off as a little stream from one part of the orifice,
but that with the roar the water escapes about equally from
each part of the hole. In the latter case it is doubtless much
more finely comminuted.

65. When a jet of steam and water thus escapes into the
air, the particles of water, from their size and consequent
weight, will soon move faster than the atoms of water which
were discharged in the gaseous state. From this follows the
question. Are the particles of water charged by rubbing against
the gaseous matter? To this it must be answered, that this
electricity was not generated in the former experiments (46,
53.), where water, gaseous matter and friction were present.
Also, no experiment is known in which gaseous matter is cer-
tainly charged electrically by friction. (See Dr. Faraday's
paper on Steam Electricity, Experimental Researches in Elec-
tricity, vol. ii, p. 106.)

Q6. A jet of steam being discharged into the air becomes
magnetic (ll.)j which I attribute to currents of electricity
passing from the hotter to the colder particles (33.), in this case
steam and air; the steam, or water which was discharged as
steam, being positive, and the air negative. When particles
of water are projected through the steam-cloud, I suppose they
collect together the minute positive particles, thus becoming
themselves positively electrified, leaving the gaseous matter
negative. I have yet made no direct experiments to ascertain
the minimum pressure at which these effects are produced,
but I am certain they may be obtained at a much lower pres-
sure than 40 lbs. on the inch.

67. Since these electrical effects are produced by the trans-
mission of drops of water through a steam-cloud in the act of
formation, it appears to me that these electrical developments
may occur in the atmosphere. In my experiments, the drops
of water were so fine that they were separated with difficulty
from the air, but I see no reason for supposing that the elec-
trical action would be essentially different if the drops were
so much larger as to separate themselves by their weight.
Lightning will thus result from a rapid condensation, the de-
scending rain and mist being positive, leaving the upper re-
gions negative.
i^ 68. I would have this explanation of the cause of lightning

Mr. T. S. Davies on Geometry and Geometers. 497

to depend, at present, as little as possible on the mechanical
violence of ths drops of water; because some experiments, not
yet fit for publication, seem to show that when steam and air
at the same temperature are discharged into the atmosphere,
the amount of water simultaneously discharged may be greatly
reduced, perhaps to nothing,

69. The negative state of the air, which one would expect to
find particular!}' strong just after a thunder-storm, may slowly
discharge itself on the earth by conduction, or on the clouds,
or rain, and thus to the earth by convection; nevertheless the
direct tendency of lightning, according to this theory, is to
render the upper regions negative ; and the facilities for the
return of this negative charge to the earth will decrease in
some proportion as the altitude increases. The continual
thunder-storms of the hotter climates may therefore gradually
accumulate a powerful negative charge in the heavens. Sup-
pose now, when the air is thus highly charged, that a co-
lumn of mist sufficiently high and dense to act the part of an
electric conductor to the positive earth and negative heavens
should be interposed between them, the electricity would then
pass as a series of disruptive discharges, and would, I suppose,
be the aurora.

7 Prospect Place, Ball's J*oncl Road,
3rd December 1849.

LXII. Geometry and Geometers. Collected hy T. Sr Davjes,
Esq., F.R.S. and F.S.A.^

No. IV.

'T'HE printing of the three letters of John Bernoulli to
■* Cramer, which I had designed to give as the next of
this series of " gossipings," must be deferred for awhile; as,
from particular considerations, I am led to think it desirable
to confine myself, for the present at least, to matters of more
purely English interest.

In 1747 Mr. Thomas Simpson published the first edition
of his Elements of Geometry; and in 1756 Dr. Simson the
first edition of his Euclid. In this latter work are two notes
upon objections which had been raised in the former, to some
of Euclid's processes. In 1760 Mr. Simpson published the
second edition of his Elements, in which he defends himself
with great earnestness on those topics; and Dr. Hutton (in
his Life of Simpson, prefixed to the Select Exercises, ed. of

♦ Cominunicated by the Author.
Phil. Mag. S. 3. No. 239. Siippl. Vol. 35. 2 K

498 Mr. T. S. Davies on Geometry and Geometers.

1792) states that these criticisms of Dr. Simson's gave him
"some trouble and vexation," — though on what ground, except
his own sensitive nature under prostrated health and its con-
sequent depression of spirits, it would be hard to tell. The
man who could maintain his temper under the offensive
ribaldry of the notorious Robert Heath, could not on any
other supposition than this, feel wounded vety deeply by the
plain, though, it must be confessed, somewhat contemptuous
language of Simson, in those notes. Dr. Hutton further says,
that Dr. Simson again replied in the notes to his next edition
of Euclid (Life of Simpson, p. xi.). Also Dr. Trail (Life of
Simson, p. 31), remarks that "some animadversions were
made on this edition (1756) chiefly by those whose works had
been criticised in the Doctor's notes; and to some of these,
in a second edition, replies and explanations were made."
These, of course, Simpson never read, as the edition referred
to was not actually published till 1762, whilst Simpson died
the year before, and had been some months prior to this in a
state that precluded reading and study of every kind. Nor
is there in the notes at the end of the second edition of his
Geometry anything to induce a belief that he wrote them
under any irritable feelings ; and we have his distinct aver-
ment, at p. 263 (1 quote from the fourth edition, which seems
to be paged precisely as the previous two), that he was igno-
rant of the existence of Dr. Simson's Euclid till the middle of
November 1759, and his own work is dated March 3 of the
following year, when he was in a most enfeebled condition.
This was indeed his last connexion with the press, if we ex-
cept his preparation of the Ladies' Diary for the following
year; in which, however, there is reason to believe that he
was greatly assisted by his friend and successor, Edward Rol-
hnson.

I have collated with some care the one hundred and five
notes given by Dr. Simson in the first and second editions of
his Euclid. There are but few variations in the greater part
of them ; and even these m.erely verbal, or of the most casual
kind. As regards our present purpose, it is enough to state
that in the 8vo edition Simpson is referred to four times, and
in the ^to only twice; and that these two notes are alike in
both those editions. They are upon i. 22, 24? and 25, and
xi. 1; the second and fourth of these ^rst appearing in the
8vo edition.

Dr. Simson, however, wrote a more expanded series of cri-
ticisms on Mr. Simpson's notes, a copy of which (in Nourse's
hand) is amongst the papers I formerly described. An exact
transcript of the original it evidently is; and a memorandum

Mr. T. S. Davies on Geometry and Geometers. 499

at the head identifies its authorship and purpose. The paper
itself has much the appearance of being intended for press,
though there is not the least reason to think it ever was
printed. On this account I give it entire. Probably it was
cancelled on account of Simpson's intimacy with Nourse.

" Remarks upon some of Mr. Thomas Simpson's notes at the end of
the second edition of his Elements of Geometry.

"Art. 1 . In page 257 and the next there is a long note, one design
of which is to show the impropriety of conceiving one figure to be
transferred from one place to another when the thing in hand can be
done another way ; he says Euclid has never recourse to this in other
cases ; but Euclid not only uses it in the 4 Prop. 1 and in the 24
Prop. 3. but also in the*4 Prop. 6. where he might instead of con-
ceiving one of the triangles contiguous to the other with its base in
the same straight line with the base of the other, have constructed a
triangle in that position, having its sides equal, each to each, to the
sides of the other ; and in like manner the corollary of 1 Prop. 6
might have been shewn ; but it would have been quite needless in
either case. Mr. Simpson himself uses this method in the axiom
before his 7'^ Book, where without the least necessity he conceives
the figure PQR to be formed equal and similar to the bases ABC,
DEF and the prisms upon these last bases to be placed upon the
base PQR ; whereas he needed only have conceived the prism on the
base ABC to be applied to the prism on the base DEF so as their
bases may coincide ; but he has been afraid that they could not stand
both together upon one base, and therefore he bids place them suc-
cessively upon the base PQR."

The reader will remark the quaint humour of the close of
this article : but long experience convinces me that very few
pupils are able to abstract all notions of impeiietrahility when
considering the geometry of solids. The term "solid" is
indeed an unfortunate one to have chosen, by which to desig-
nate a fifjure of three dimensions; and it is difficult to remove
from the young mind some vague notion of the impossibility
(or absurdity of directing it) of applying one solid to another
so that both shall be in the same place at the same time. The
method of Simson's Euclid is unquestionably legitimate : but
something must be conceded in the outset of a new course of

• • • m

study to the youthful incapacity for abstraction. The con-
ception of both solids being successively fitted into the same
matrix, or in the form that Simpson gives it, is less likely to
violate previous notions, than the more abstract and certainly
more philosophical process. Neither is it inaccurate under
any aspect as a method of reasoning; and the more desirable
view will easily present itselfto the mind of the careful student
at a stage of reading not very remote.

But is the supraposition of a plane figure upon another

2 K2

'SOO Mr. T. S. Davies on Geometry and Geometers.

plane figure materially different from this? For one line to
be 071 another is surely not " coincidence " in the strict sense
of the word ; and certainly there is little reason to consider
an argument founded upon two lines so situated, as a legiti-
mate proof. Yet how few who have read Euclid have any
other idea of supraposition ! Euclid does not use the term;
and no commentator or teacher who does use it, would pass
it by without showing in what sense it is used. This is easily
done by recalling the definitions of the point, the line and the
plane, to the student's mind. The difficulty of perfect abs-
traction of some material properties is of the same nature
here as in the case of " solids;" but it is much simpler, and
more easily removed from the young mind.

As regards the legitimacy of the processes of transferring
figures, so much has been said on both sides that it might be
difficult to propound a view which somebody or other has not
taken before. One thing, however, is clear ; that no geometer
has been successful in attempting to build up a legitimate
system without the aid of this conception — either openly or in
disguise. We are forced back, then, upon the necessity of
using it; and perhaps our notions of legitimacy may be of
too exalted a character to be ever realised. Are we sure, in-
deed, that our conceptions of form and the other properties
of figure are not so obtained by us initially as to necessarily
involve the consideration of transfer ? Many considerations
are involved in this question which lie beyond the ordinary
range of geometrical discussion. It was evidently Euclid's
desideratum to evade it; and yet he was unable to do so in
i. 4, i. 7, and Hi. 24 : nor has any one else succeeded in doing
so with perfect strictness.

That this method of transferring figures was amongst the
very earliest modes of demonstration^ there can be no room to
doubt; and that it was much more used (even in the school
of Plato) before the time of Euclid, appears to me extremely
probable. Little, perhaps nothing, is likely to be found of a
documentary character either to bear out this view or to sweep
it away. It is a natural mode of proceeding, and it is in a few
cases even yet an inevitable owe. The I'efinements introduced
into geometrical reasoning by Euclid, or perhaps partially so be-
fore his time, induced the attempt to eliminate all idea of ;«o//ow,
as one of the properties of matter. It is on the same ground
that corresponding modern refinements have been attempted,
in which the principle should be completely carried out. That
the conditions which determined the equality of two triangles
were not determined originally without the adoption of the
principle of transfer is almost certain; and as to many pro-

Mr. T. S. Davies on Geometty and Geometers. 501

perlies of the circle in the third book, the two circles being
left (both in the enunciation and demonstration), can only be
accounted for on the hypothesis that the proofs we now have
were modified from proofs by transfer. This (as well as the
fact that most of them would be more neatly exhibited in re-
ference to a single circle than to two) would seem to point
out the change as an immediately recent one — most probably
Euclid's own change. I cannot, however, further enlarge
here upon this question.

" 2. P. 261- The reasoning here is such that it is difficult to
know what his meaning is. ' he says the question here, is, whether
a triangle, under certain specified conditions, can, or cannot be
formed ? and therefor [e] to conclude any thing from the properties of
Triangles would be ridiculous, and nothing less than begging the
question.' does he mean that because the triangle is to be made,
and not yet formed that therefore it is not allowable to conclude
anything from the properties of triangles which have been already
demonstrated ? Were this true, he would, indeed, be in the right
to affirm as he does that the problem has a limitation, yet it would be
absurd to urge it in this case : he makes use of his own limitation
in this Problem, and why may not Euclid make use of his which is
easier to be understood, and the consequence from it that the circles
will meet sufficiently plain. But really this deserves no serious
reply."

That the conclusion of the intersection of the circles can
be obtained from Euclid's limitation (viz. that any two sides
of a triangle are greater than the third), is true enough : but
that it is actually made to follow by any reason beyond " in-
spection " no one surely will say. A process tantamount to
Simpson's is essential', and whilst many may think that the
objection does " deserve a serious reply," no one will, I think,
consider what is given above as any reply at all.

"3. In the same note he observes that the point F ought to have
been shown to fall below the line
EG (or rather, because the point G
is found by construction, that the
point G falls above EF.) this pro-
bably Euclid omitted, as it is easy to
see that DF being greater than DE
the angle DFE is less than a right
angle, and producing EF to H that
therefore DFH is an obtuse angle,
and consequently any straight line DH drawn to EF produced must
be greater than DE, and that DG which is equal to it must fall
above EH."

That Simpson's objection was a valid one is now unques-

502 Mr. T. S. Davies on Geometry and Geometers.

tioned : whether the present completion of it, or that given in
the note upon /. 24- be satisfactory or not, will give rise to
different opinions. It will be necessary to prove what Dr.
Simson assumes in the opening of the above reply, that DFE
is less than a right angle ; and as to that in the note in Euclid,
there is an assumption not at all warranted by anything prior
to i. 24< : — except, indeed, the warranty of his own precedent
in /. 13.

Simpson administers a very proper and dignified rebuke to
the Doctor in the same note, but which is not noticed either
in this MS. or in print.

" Professor Simson (at p. 359 of his Euclid, 4toedit. 1756)
has been a little severe upon me, on this head, for attempting
to supply, what I thought a small defect in Euclid. ' Who is
so dull (says he) tho' only beginning to learn the Elements, as
not to perceive that the circle described from the centre F &c.'
It is not without a real concern that I here see this able Geo-
meter drop his own character so far as to express himself in
a manner so very ungeometrical . If the thing is indeed so
easy to be perceived, it must be so either as an object of the
senses, that is, in plain terms, by inspection; or else it must
be in consequence of geometrical reasonings antecedent to the
thing itself. Now I am clear that he would not be thought
to mean the former ; and as to the latter nothing had been
given from which the evidence of the inference could be so
clearly seen : For though, &c."

It may be added, that a particular object induced me a
little time ago to note the assumptions that are tacitly made in
the first book of Euclid. Whoever does the same will not be
a little sui'prised at their number.

There is no doubt that Simson removed a great number of
small blemishes from Euclid's Elements; but, it is equally
certain, that he has still left a great many more than he has
removed. He found some of them too firmly rooted into the
system to be able to eradicate them without venturing upon
far greater changes than he has done — and he showed no
*' lack of courage " in that way, either. The present is one of
them; for the proof ought to form part of the text; whereas
it is treated in a note as a thing " easy to see." The same
assumption in a still more objectionable connexion occurs in
the construction of?. 13. For there it is assumed that the
circle whose centre is C, and which passes through a point D
oji the other side of the line AB, will cut that line in two points,
F and G; as otherwise the construction following could not
be performed. It is also to be presumed that the circle can
only cut the line in those two points ; as if it cut in more than

Mr. T. S. Davies on Geotnetry and Geometers. 503

fi{n 1)

two, say «, then there could be -^-^ — perpendiculars drawn

from C to AB. The line FG must then fall taholly 'within
the circle; whereas when we come to the third book we are
required to prove this very property ; and more strano^ely still,
to draw a straight line isoithin the circle in the antecedent pro-
position. The difficulty is inherent in the method pursued.
// compels the eye to supply the place of reason. We merely see
that it is : — not know why it must be so. It is not by such
phrases as "who is so dull as not to see?" or "it is easy to
see," that this blemish can be removed.

I believe that no one who has been much concerned in
mathematical education will complain of students " only be-
ginning the Elements " being very short-sighted upon such
points as these. They find it " easy to see" that many things
are so and so which the tutor would prefer their proving. In
these cases, it is not the fact that is in (juestion, but its place
in the logical system. Geometry by inspection is always more
acceptable to the majority of young students than geometry
by demonstration. Mr. Byrne must have known this, when
he carried the system to perfection in his Euclid in Colours.
Did geometry, however, stop at visible properties^ it would be
jejune enough. I have often found, too, that the notion of
the ultimate objects of geometrical research being principally
graphic, or in some other way merely practical, has, whilst it
has fostered the propensity to proof by inspection, generally
led to much confusion in the student's mind. Let it always
be presented to his mind as a rational science — never as a
practical art, except, indeed, incidentally.

" 4. In the same place he blames the bidding ' draw a straight
line within a circle, without specifying that it must terminate in the
circumference ' not knowing that this way of speaking is constantly
used by Euclid and other Geometers ; as not only in this P*. of the
3^ but in tlie 4, 14, 15, 28 of the same book, and though the 2 Prop,
of the 3*^ is to prove that a straight line joining any two points of
the circumference is within the circle, yet surely there is no need of
demonstrating that a straight line may be drawn somewhere within
the circle ; the 2"* Prop, being to shew that though the points be
taken never so near to one another, that the straight line joining
them will neither fall upon nor without the circumference,"

Simpson had only noticed this as an instance of vague ex-
pression. Is it not such? Is it not more — even much more?

" 5. In the same note he answers what is said in page 415. of the
4*° English Edition, that it ought to be demonstrated not assumed
that a straight line cannot meet a straight line in more than one
point, and says it cannot be demonstrated, and that the Editor refers

*0i Mr. T. S. Davies on Geometry and Geometers.

it to the 14"^ axiom of Booli 1. (he means in Barrow's Euclid, for it
is the 10*^ in the Greek), hut all that in this case follows from that
axiom is that if two straight lines
AB, CD could meet with each
other in two points E, F, the parts
of them betwen E F must coincide,
and so A B, C D would have the
segment common to both ; but this
does not prove that they cannot
meet in two points, from which
their not having a common seg-
ment is deduced in the Greek Edition, but because they cannot have
a common segment, as is shewn in Cor. of 1 1 Prop. 1. 4*" Edition it
follows they cannot meet in two points."

As regards a logical system, Dr. Simson is right in this
view; but in all that relates to the line and plane, especially
the first steps of deduction, there exists in most minds some
degree of confusion, arising from the vagueness of the defi-
nitions of those objects of our contemplation. In discussing
Euclid's method, it appears to be almost always forgotten that
his metaphysical creed was Platonism ; and questions arising
out of such antecedent creeds always must present themselves
in the initial steps of a science.

It cannot be denied that Simpson might have retorted, had
he seen this, " who is so dull as not to perceive that two
straight lines cannot meet in two points?" It would be an
assumption far less removed from our first conceptions than
some that Euclid makes and Simson justifies.

" 6. P. 265. The observation at the end of the note which begins
in p. 264, viz : that in the Corollary (of Prop 11 Book 1.) the lines
A B, B D, B C are supposed to be all in the same plane, which can-
not be assumed in 1 Prop. 11. is very just. Soon after the 4*° Edi-
tion was published I observed this error and corrected it in the way
Mr. Simpson has mentioned in this note, he is mistaken in thinking
the 10'** axiom he mentions here, to be Euclid's, the Axiom he means
is That two straight lines cannot have a common segment, which is
none of Euclid's, but is the 10*''. in Dr. Barrow's Edition, who took
it from Herigon's Cursus vol. 1. and to supply this, is the design of
Corollary 11 Prop. 1.

" 7. Page 267. and the following contain several objections against
Euclid's doctrine of Proportionals, most of which with many others,
have been long ago distinctly and fully answered by the learned Dr.
Barrow in the 7*^ and 8"* of his Mathematical Lectures. Some of
which relate to the notes on the 4*° Euclid are as follows.

" 8. At the bottom of P. 270 he says that ' Euclid or Eudoxus
does never (that I know of) refer to any definition till he has proved
either by actual construction , or by some Demonstration previous to
that in hand, that such definition involves no absurdity &c.' the

Mr. T. S. Davies on Geometric and Geometers. 505

contrary of this is manifest, for instance in the 4*'' Prop. 5 he refers
to (or makes use of ) 5 Def. 5 without ever having mentioned it, or
proved anything about it, after he had given it, D"^. Barrow^ has
sufficiently shewn the weakness of such objections ; see his Lect.
Mathem : P. 299 near the end, and the sentence which begins in
the last line of Page 303. nam si &c."

,*■ Dr. Simson must have been " hard driven " for an objec-
tion to Simpson, to have quoted this case: inasmuch as it so
far furnishes a new argument against ihe petjection of Euclid's
work ; and thereby affixes a stigma to the '* 4**^ Edition,"
which is as yet unremoved from any subsequent one. That
the canon enforced by Simpson is a safe, a sound, and an
essential one, who will deny? Nay, more: — not only should
the consistency of the definition be shown, but its completeness,
and xia freedom from redundancy^ likewise. There is perhaps
no instance in Euclid of incompleteness of defining conditions:
but there are several of redundancy — such as the square, and
similar rectilineal figures, so often quoted by editors and com-
mentators. The mischief done in such cases as these is rather
done to the logic than to the geometrical facts : but then, on
the other hand, these superfluous conditions might be contra-
dictory to the essential ones, just as easily as consistent with
them, or consequential from them.

Instead of collecting all the definitions at the beginning of
a book er treatise, many judicious writers prefer to give them
pari passu, as the occasion for them, as well as their justifica-
tion, shall present itself. Probably the fifth definition of the
fifth book and those conhected essentially with it, may present
a good argument in favour of such a mode. In more elabo-
rate researches, and especially in the theories of modern geo-
metry, this becomes almost indispensable; as for instance in
the doctrine of " radical axes," " similitude," " poles and
polars," " anharmonic ratios " and " involution." Many
points, lines, circles, i-atios, and relations of different kinds
here dema7id speci^c names, which till their fiecessaty existefice
has been proved, it would be a manifest absurdity to confer
upon them. Under all circumstances, at any rate, whatever
arrangement may be given to the definitions in a printed book,
it is essential to observe the canon enforced by Simpson, as
above quoted, in giving the composition and logical place of
every definition.

It would require more space than I have at my disposal to
enter upon the question of Euclid's fifth definition of his fifth
book ; and as I cannot treat it adequately, it must be passed
over altogether, till some future time. For the same reason, I
shall here offer no remark upon the portions of this paper gf
Simson's, which bear upon the fifth book. ,

506 Mr. T. S. Davies on Geometry and Geometers.

Yet whilst I avoid such extended discussions as I should be
entangled in by this subject, it is certainly due to Thomas
Simpson to state, that all geometers have not entertained, and
do not now entertain, that high estimate of Dr. Barrow's
treatment of ratio that Dr. Simson did, and which he here so
triumphantly quotes. It is satisfactory to be able to state my
own view in the felicitous language of a dispassionate judge,
and of one whose philosophical acumen in such matters needs
no praise of mine, Professor Powell. In a paper read before
the Ashmolean Society of Oxford in 1836, he thus expresses
himself: — " Dr. Barrow, in his celebrated Mathematical Lec-
tures for 1666, has treated the whole subject of ratios and
proportion in the most copious and elaborate manner, but, as
appears to me, with more learning than perspicuity; he is
extensively occupied in examining and refuting such objec-
tions as those just adverted to; and in doing so seems more
explicit and satisfactory, than in any attempts to elucidate di-
rectly the doctrine itself on real philosophical principles. In
point of fact, in the midst of his very extensive dissertations,
it is far from an easy matter to discover what is his own idea
of the nature of ratios ; and when it is developed, it is by no
means clear wherein it substantially differs from the views of
some of his opponents" (p. 14). 1 not only fully concur in
this view, but I believe that much of the praise bestowed upon
Dr. Barrow's Lectures on this subject, has been bestowed for
fashion's sake, and not from those writers having read and
unravelled that complicated series of discussions.

" 9. In P. 379 of the 4'" English Edition it is said That in order
to prove what is affirmed in the Demonstration of 10. Prop. 5 in the
Greek Edition viz : that A cannot have a less ratio to C than B has
to it, it ought to have been shewn that if the ratio of A to C be
greater than that of B to C. and taking any equimultiples of A and B,
and any multiple of C, the multiple of A is ever greater than that
of C whenever the multiple of B is greater than that of C ; but this
is not done in the 10 Prop, but would easily follow from it and can-
not without it be easily demonstrated. The author of the notes on
the 8^° [4'° ? the 8vo was not published till after Simpson's death]
Edition sayes, that this point ought to have been cleared up by pro-
positions antecedent thereto and independent thereupon (I suppose
he means upon the lO''*. Proposition, else I do not understand him)
and adds that the 8'^^ Prop, seems the proper place for doing it.
then he gives an account of what is proved in Prop. 8. and next
gives a demonstration that the ratio of A to C cannot be less than
the ratio of B to C. but in the very first words of it, he supposes that
A is greater than B, which is the thing that is proved in the 10'^
Prop, and therefore he has done it by the help of the 10**^, tho, a
little before, he had said it should be done by propositions indepen-
dent upon it ; his demonstration is exactly the same with that at the

Mr. T. S. Davies on Geometry and Geometers, 507

end the notes on the 10. Prop. Page 380 of the English 4'" Edition
which he says ought to have preceded the 10*^. it can, it is true, be
done without the lO**^ but not so easily.

" 10. In P. 271. at the bottom, he sayes ' the same objection oc-
' curs again in the IS'** Prop, where it remains in its full force, for
' though it be allowed that there are some equimultiples of C and E
' and some of D and F such, that the multiple of C is greater than
' the multiple of D but the multiple of E not greater than the multiple
' of F ; yet it is not demonstrated nor in any sort shewn, that other
' multiples of these quantities cannot be taken such that the very con-
' trary shall hajjpen.' No indeed, for the very contrary may often
happen ; but this has not the least force against the demonstration
Euclid gives of the 13*** Prop, for since it is allowed, that such equi-
multiples can be taken as just now mentioned, the Demonstration of
the 13**^ remains firm and legitimate, but indeed what he sayes here
is so far from having the least appearance of an objection, that the
mildest thing [that] can be said of it is, that the author has been in
so great a hurry as not to have taken time to consider what he was
writing,

"11. In P. 272. at the foot, he mentions the principle whereby the
difficulty he had before spoken of might be obviated, viz : ' that if a
' magnitude of any kind be given, or propounded, there may (or can)
' be another magnitude of the same kind which shall have to it any
' ratio assigned,' or which is the same thing, that unto any three
magnitudes two of which are of the same kind, there can be found
a fourth proportional. This he sayes I will by no means admit of
(tho Euclid himself in 2. Prop. 12. has used it) and in P. 70 of his
Elements at the foot he had said that ' this kind of argumentation
' is authorised and adopted by Euclid himself in his twelfth book' as
to which is to be observed that Euclid in the 12 Prop. 6 has shewn
that a fourth proportional can be found to any three straight lines,
from which what he assumes in the 2 Prop. 12 can be legitimately
deduced, as is shewn in the note at the foot of the page in the 4*°
Edition [and in all subsequent ones the same note is retained] at
that proposition, but his using here will not infer that he would
have used it before he had shewn the 12. Prop. 6.

" 12. Near the end of P. 274 the author is for ' entirely rejecting
' the lO'^'and 13"' Propp. of Book 5*^ and everything else founded on
' the Definition of a greater and less ratio, as being of no other use in
' the Elements than to open the way to these important theorems on
' the alternation and equality of ratios' (by the last he means the 22
Prop. 5.) ' which may be better demonstrated without them, from the
• Definition of equal ratios alone, &c.' but tho the 14*** and 20"»
Propp. 5 on which the 16. 22. depend, can be shewn without the help
of the lO^'^and 13*** yet since these two last are frequently used both
by antient and modern geometers, they ought to have a place in the
Elements ; and since they are there, it was proper to demonstrate
the 14"> and 20''» by them as it is done without any construction
by taking equimultiples.

" 13. As to what is said concerning a nature or idea (' see P. 273'

.508 Mr. T. S. Da vies on Geometric and Geometers.

in margin) antecedent to that given in the 6"' and H*^ (he means the
S*'* and 7'^ in the Greek Text) Definitions of the 5'^ book, D^ Bar-
row has so fully answered it that nothing further need be added.

" 14. Tho Mr. Thomas Simpson is a very able Mathematician,
yet he is very much displeased at the high encomiums and extrava-
gant commendations that have been lavished on this 5^^ book of
Euclids ; and adds that ' this superb fabrick of proportions, reared
' with so much art, stands upon a tottering foundation' but D"". Bar-
row who gives it the highest Encomiums, and who is the person, I
believe, he chiefly intends here, was, as is well known, an exceeding
modest man, and never launched out too far in behalf of opinions he
had adopted; he was on every account, one of the best judges of
this affair, and with respect to such objections as have been here
taken notice of against Euclid's Definition sayes in Page 297 of his
Led : Mathem : that this definition ' nisi machinis impulsa validori
' bus in eeternum persistet inconcussa.'"

I have not observed in Simson's correspondence with
Nourse, any allusion to this paper. It does not, indeed, fol-
low that because no chasm appears in the letters of this period
between them, by reference to missing ones in subsequent
letters, that all the letters which Simson wrote to Nourse (the
one, specified formerly, excepted) are preserved. It is not
unlikely that this paper was written soon after Simson's re-
ceipt of Simpson's book; as much to satisfy Nourse with his
purchase of Simson's copyright as anything else*. One or
two passages of the ad captandum kind would seem to bespeak
such a purpose. Why else the sneer about the able " mathe-
matician " at the opening of art. I'l, as a preliminary to his
being so strongly contrasted with Dr. Barrow for modesty
and learning? The character of the paper is, on the whole,
marked by a hauteur towards Simpson, that is only excusable
in the writer, from a consideration of his age and the profound
respect with which he had so long been treated by his own

* It is a remarkable circumstance, that whilst Simson's Euclid is the
universally-adopted text-book iu geometry in England, it is almost as uni-
versally discarded in the Scottish schools and colleges — even in Glasgow
itself. In Ireland, Elrington's edition is used; and on the Continent, the
Elements is only viewed as a work of learned curiosity, and quoted, where
quoted at all, for the purpose of animadversion. The honour of a prophet
in his own country is here verified indeed ! I have often thought, whilst
reflecting upon this, that the maintenance of the preference for Simson's
edition in this country was due to the earnest manner in which its supe-
riority was urged at Cambridge by Dr. Robert Smith, and the respect paid
to Nourse's known good judgement at Oxford. Probably, but for this,
Thomas Simpson's Elements (the best, perhaps, we yet possess, which does
not follow close in the wake of Euclid) might have now held the same
position in this country that Legendre's does in France; at least if our na-
tional propensities to admire everything antique should not have given rise
to some new translation with its distinguishing variations.

Mr. T. S. Davies on Geometry and Georheten. 509

little circle in Glasgow. Simson was there, what Johnson was
in his "Club" in Fleet Street.

Simpson is the only author referred to by Simson, who was
both British and unadorned by academic titles ; and he is
introduced into the first and second editions of the Euclid
almost by inevitable necessity. Throughout, he is rather a
social pay-verm than a scientific brother. In many of the
views of the preceding paper I concur: still I cannot but re-
gret the tone in which some of them are expressed. The
mode, too, in which Dr. Trail refers to Simpson is in too
strict keeping with a feeling of contempt towards " those
whose works had been criticised in the Doctor's notes;" the
reference applying, as far as I have been able to ascertain,
to Thomas Simpson only. No other author of the time is
mentioneii, or even alluded to, in Simson's Notes, and indeed
no other work on the Elements of Geometry was published
during the interval in question. The first edition of Emer-
son's was in 1763, and 1 find no allusion there to Simson or
to Simpson either.

I have more particularly alluded to the matters in the pre-
ceding paragraph for the purpose of remarking that if a ma-
thematician of Simpson's eminence (and I may add of Simp-
son's Eurojiean reputation too) could be thus sijffie by " titled
scholars," we cannot wonder at the general neglect with which
the host of geometers in humble life, during the last century and
first quarter of the present one, have been treated by academic
bodies*. Few of my readers have the least idea of the exist-
ence of a body of men who, through several successive ages,
have cultivated geometry with an ardour that is probably un-
exampled, and with a degree of success commensurate with
that ardour. Their reward, as well as their patrimony, was
poverty ; and their fame was limited to their own narrow circle.

• As a specimen of even a somewhat recent manifestation of this spirit,
1 may quote Dr. Cressweli's treatise on Maxima and Minima. He says,
" the Elements of Thomas Simpson contain a series of propositions on the
Maxima and Minima of Geometrical Qnantities, in which there is not
mnch that is original" (p. 5). I confess myself unable to find in any
writer antecedent to Simpson, a large relative portion of the propositions
in his book, and I cannot accede to the dictum of Dr. Cresswell, except in
the qualified sense of the chapter itself being a 'little ' one— barely fifteen
pages. But when a writer thus becomes critical upon the subject oforigi.
natifi/ in others, we have a right to test him by the same criterion. What
is there *' new" in Dr. Cressweli's own treatise, either as to principle, me-
thod of development, or final result ? Certainly a finer opportunity for the
production of a truly classical work on the subject was never thrown away
by any writer. Cressweli's volume on this one subject is really larger than
Simpson's entire treatise on geometry generally. No man can do much in
fifteen pages, but any competent person might do a good deal in 273.

510 Mr. T. S. Davies on Geometry and Geometers.

Their works, however, live after them : but at present, chiefly
forming portions of books of high pretensions, and bearing
other names than theirs on the title-pages. These were men
of the school of Thomas Simpson ; their career was marked
out by him; and. their tastes were formed upon the models
which he bequeathed to them. It may be safely affirmed that,
as regards geometry generally, and geometrical construction
especially, no works in our language furnish so many beauti-
ful, varied, and instructive exemplars as the three works of
Simpson, viz. his " Elements of Geometry," the supplementary
part of his "Elements of Algebra," and the second part of
his " Select Exercises.^^ It is much to be regretted that Dr.
Stewart's Propositiones Geometrical was not added to the
scanty libraries of these able geometers, by its being published
in their own, instead of a dead lancjuage. That day of learned
loppery is, however, gone by, when a man who wishes to
publish a work on science must claim his title to " respectable
birth, parentage, and education," by his Latin prose composi-
tion, before he can obtain the notice of the dilettanti of the
so-called literary and scientific world. Justice, however, will
yet be done to these men, humble artisans, excisemen, and
country-schoolmasters though most of them were. The able
analyses of their little duodecimo annuals which is in progress
in the Mechanics' Magazine, by Mr. Wilkinson of Burnley,
will do much towards effecting this purpose; and I should
hope that book- manufacturers will in the end be compelled to
bow to the force of public opinion, so far as to give at least
some distinct acknowledgement of the sources whence they
obtain the materials of their works. A work might be
pointed out — a work which has passed through several large
editions, and produced to its "author" large sums of money —
which is made up 'wholly owi of the periodicals written by these
men — without, in any single case, more than a verbal alteration
in the solutions, and very rarely even so much as that. Yet
there is not the least hint given as to whence these beautiful
investigations were taken ; nor indeed any marked indication
that they did not "drop from the clouds," or were the honest
produce of the mind of him whose name adorns the title-page.

Shooters' Hill, Oct. 27, 1849.

[ 511 ]

LXIII. Illustrations of a Method for computing Magnetic
Declination^ on the principle proposed by Professor Gauss.
By Samuel Beswick*.

THROUGH the kind suggestion of the Astronomer
Royal, I have been induced to examine attentively the
elegant and profound Essay of Professor Gauss on the subject
of Terrestrial Magnetism. For some time I have used a
method for computing magnetic declination, differing from
the one proposed by this eminent magnetician, though the
involved principle is precisely identical: but this fact was
wholly unknown until very recently. The method referred
to has been applied with varied success to more than three
hundred places, their localities being distributed over the four
continents and the principal oceans. A specimen of its ap-
plication to Greenwich, its antipode Sydney, and St. Helena,
is presented in this communication for the examination of
your readers. The principle of Prof. Gauss's method for
computing magnetic declination is given in these words (Tay-
lor's Scientific Memoirs, vol. ii.) : —

" Consequently there are on the earth only two magnetic
poleSf apart from the possible case of local exception spoken
of in art. 13."— P. 223.

" The two extreme values of V correspond in this point of
view to two poifits, inclosed by the zones, at which the hori-
zontal force is =0, and where therefore the whole magnetic
force can only be vertical ; these points are termed the magnetic
poles of the earth." — P. 195.

" We proceed to develope the mode of subtnitting them to
calcidation. On the surface of the earth V becomes a simple
function of two variable magnitudes, for which we will take
the geographical longitude reckoned eastward from an arbi-
trary first meridian^ — and the distance from the north pole of
the earth (a complement of geographical latitude)." — P. 199.

*' Resolving the horizontal magnetic force into two portions,
one of which, X, acts in the direction of the geographical
meridian, and the other, Y, perpendicularly to that meridian,
— and considering X as positive when directed towards the
north, and Y as positive when directed towards the west." —
P. 200.

I propose to give a demonstration of the above method,
essentially differing from the one given by the Professor, and
such as 1 have used for years.

* Communicated by the Author.

512

Mr. S. Beswick on a Method for

Explanation of the diagram. — The letters a^ h represent
the situation of the earth's poles; the capital letters A, B re-
present the two orbits of the magnetic points of convergence
or poles ; and b^ g represent those poles.

Proposition. — Given the latitude and longitude of each
magnetic pole, or point of convergence of the horizontal force,
and of the place of observation, to find the declination of the
needle at the said place.

Mean Declination at Greenwich for the present year 1849.

(1.) N. lat. 51° 29' : comp. 38° 31'.
long. 0°. 0'.

(2.) Lat. and long, of N. magnetic pole.

N. lat. 70'' : comp. 20°.
W. long. 91°.

(3.) Obtain the value o^ zza trigonometrically thus: as
bzza : ba :: abzz : zza.

Or thus:

computing Magnetic Declination. 513

sine 20° 0' . . . . 9534-05 *

sine 1°0' . . . . 824186

sine 20' ... . 777591
Throughout the computation we shall consider it useless to
subtract the radius, which only leaves the result without the
Jirstjigure. The middle sine 1° is obtained thus :

91° (as above) -90°= 1°.

(4.) Lat. and long, of S, magnetic pole.

S. lat. 75^ 5': comp. 1 i° 55'.
E. long. 155°.

(5.) Obtain the value of yyh in the same way as in item
third.

155° -90° = 65°.
sine 14.° 55' ... . 941063
sine 65° 0' ... . 995728

sine 13°29' . . . . 936791

(6.) Obtain the value of zzc thus : add, or subtract, as the
case may be, the value o^ zza^ found in item third, to the com-
plement of latitude or rtc.

38° 3l' + 20' = 38° 51'.

(7.) Allow 20" to every degree 'without the orbit of the
magnetic poles, for the variation of intensity, and 1' to every
degree within the orbit.

38° 5 1'x 20" =12' 57"
20° 0' X 1' =20' 0"

32' 57"

(8.) Ol)tain the distance zzyy thus :

zza + ah + hyy ;
or

1 80° + 20' + 1 3° 29' = 1 93° 49'.

(9.) Correct for the earth's rotundity in latitude, thus :

ah^ : zzyy'^ : : 32' 57" : 38' 12".

These minutes are for every ten degrees of the distance azc;
hence

38° 51' X 38° 12'-?-10 = 2° 28'.

This number is used for the correction of latitude, thus:

20° + 2°28' = 22°28'.

Phil. Mag. S. 3. No. 239. Suppl. Vol. 35. 2 L

51* Mr. S. Beswick 07i a Method for

(10.) Correct for the earth's rotundity in longitude. At a
distance of" 90° from each pole all angles vanish ; I therefore
take the least and greatest distances of the magnetic pole, and
proceed in a duplicate ratio, taking 90° as a basis, thus:
70°2: 110°:: 51° 29°-^: 59° 30':

which is the same as saying, as the square of the least distance
of the magnetic pole is to the greatest distance, so is the square
of the latitude of Greenwich to the number required.

This number must be adapted to the angle of longitude by
the correcting nuniber in the middle clause of item ninth.

90° : 59° 30' : : 2"^ 28' : 1° 37'.

This number is used for the correction of longitude ; thus,
m the present case,

91°-1°37'=89°23'.

(11.) Having made these corrections, now obtain the tri-
gonometrical values of the side and angle, be and boa.

First find the side dc, thus : as the radius is to the sine ac
(38^ 31'), so is the sine dac (89° 23') to the sine dc, or thus :

sine 38° 31' . . . . 9794-31
sine 89° 23' .... 999997

sine 38° 31' ... . 979428

Find the side da, as follows: as the tangent to the comple-
ment ac (38° 31') is to the whole sine, so is the sine of the
complement cad (89° 23') to the tangent ad (29') j or thus :

sine of comp. and rad. 8.9° 23' . . 1803194
tang, to comp. . . 33° 31' . . 1009914

tan 29' . . 793280

The side be may now be found in the following manner.
Obtain bd by adding ba and ad, thus :

22° 28' + 29' = 22° 57';
then be results from the following proportion : as the radius
is to the sine of the complement dc (38° 31'), so is the sine of
the complement db (22° 57') to the sine of the complement be
(43° 54'). Or logarithmically thus :

sine to comp. 38° 31' . . . . 989344
sine to comp. 22° 57' .... 996419

sine to comp. 43° 54' ... . 985763
This is the value of the side be.

(12.) Now find the angle bca, thus : as the sine be is to the
sine bac, so is the sine ba to the sine bea. Or thus :

computing Magnetic Declination. 515

sine 22'' 28' .... 958223 -i.

sine 89° 23' ... . 999997 niP.lAh

1958220
sine 43° 54' ... . 984098

sine 33° 26' .... 974122
which is the angle bca.

Inasmuch as the process for finding the values of the sides
and angles, and the corrections for the earth's rotundity in
latitude and longitude, is precisely identical when applied to
the southern hemisphere, it would be useless to repeat the
explanations and details of the process. But in order to faci-
litate the computation, and yet avoid repetition, corresponding
items shall be arranged under corresponding numbers.

(6.) 38° 31'- 13° 29' = 25° 2'.

(7.) 25° 2'x20"= 8' 20"

14° 55' X 1' = 14' 55"

23' 15"

(8.) 180° + 20' +13° 29' = 193° 49'.

(9.) 32400 : 37564 : : 23' 15" : 26' 57".

26'57"x25°2'^10=:l° 7'.
14° 55'+ 1° 7'= 16° 2'.

(10.) 75° 5'2 : 104° 55^ : : 51° 29'^: 49° 19'.

90° :49° 19':: 1° 7' : 36'.
155° +36' =155° 36' : compl. 24° 24'.

(11.) sine 38° 31' .... 979431

sine 24° 24' ... . 961606

sine 14° 54' . . . . 941037

sine of comp. and rad. 24° 24' . . 1995937
tang, to comp. . . 38° 31' . . 1009914

tang 35° 56' . . 986023

35° 56 — 16° 2' =19° 54'.

sine to comp. 14° 54' .... 998515
sine to comp. 19° 54' . . . . 997326

sine to comp. 24° 41' ... . 995841

The complement is 155° 19'.

2 L 2

§1$ Mr. S. Beswick on a Method/or

(12.) sine 16° 2' .... 944122

sine 24° 24' ... . 961906

1905728
sine 24° 41' ... . 962076

sine 15° 51' . . . . 943652
which is the southern angle.

(13.) Having obtained the two sides and angles required
by the theory of Gauss, we now proceed to find the value of
the angle bcx formed by the needle. As the sum of the sides
bc + cg (43° 54' -1-155° 19'=199° 13') is to the sum of the
angles or bca+gch{33° 26'+ 15° 5l' = 49° 17'), so is the north
side 6c (43° 54') to the angle bcs {10° 51'). Or more clearly
thus :

Sides. Angles.

43° 54' 33° 26'

155° 19' 15° 51'

199° 13' : 49° 17' : : 43° 54' : 10° 51'

Hence if bcx be subtracted from bca, there will remain the
angle xca which the needle makes with the meridian of Green-
wich, in other words the declination.

33° 26'
10° 51'

22° 35' W.

which is the mean west declination at Greenwich for the pre-
sent year 1849.

Mr. James Glaisher, of the Royal Observatory, informed
me, June 27, 1849, "that the average value of the W. declina-
tion at Greenvoichy at present, is about 22° 35'."

Calculation of the Mean Declination at St. Helena for the
present year 1849.

(1.) S. lat. 15° 55' : comp. 74° 5'.

W. long. 5° 43'.

(2.) Lat. and long, of N. magnetic pole.
N. lat. 70° : comp. 20°.

(3.)

W. long. 91°-5° 43'

90° -85° 17' = 4° 43'.

sine 20° O' . . .
sine 4° 43' . . .

= 85° 17'.

. 953405
. 891502

sine 1° 37' . . .

. 844907

computing Magnetic Declination.

(4.) Lat. and long, of S. magnetic pole.

S. lat. 7.5° 5' : comp. U° 55'.
E. long. 155° +5° 43'= 160° 43'.

(5.) 1 60° 43' - 90° = 70° 4S'.

sine 14° 55' ... . 941063
sine 70^ 43' ... . 997492

sine 14° 4' . . .

517

(6.)
(7.)

(8.)
(9.)

(10.)

(11.)

. . . 938555

74° 5'+ 1° 37' = 75° 42'.

75° 42' X 20" = 25' 14"
20° O'x I' =20' 0"

45' 1 4"
180°- 1° 37'4-14°4'=192°27'.
32400 : 37037 : : 45' 14" : 51' 39".
51' 39"x 75° 42'^ 10 = 6° 30'.
20° +6° 30' = 26° 30'.

70°2: 110°:: 15° 55'^ : 5° 40'.
90° : 5° 40' : : 6° 30' : 24'.
85° 17' + 24' = 85° 41'.

sine 74° 5' .
sine 85° 41' .

998302
999877

sine 73° 31' . . .

sine of comp. and rad. 85° 41' . .
taug. to comp. . . . 74° 5' . .

tang 14° 47' . .

14° 47' + 26° 30' = 41° 17'.
sine to comp. 73° 31' . . . .
sine to comp. 41° 17' . . . .

sine to comp. 77° 41' . . . .

(12.) sine 26° 30' . . .

sine 85° 41' . . .

998179

. . 1887661
. . 945511

942150

945292
987590

932882

sine 77° 41' .

sine 27° 6' .

which is the northern angle.

964953
999877

1964830
998989

965841

518 On a Method for computing Magnetic Declination.

(6^ O. BJWls 74O 5,.^ j^O 4.^ = 830 gf^

(7.) 88° 9' X 20" =29' 23"

i4°55'x 1' = 14.' 55"

44.' 18"
(8.) 180^-1° 37' + 14° 4'= 192° 27'.

(9.) 32400 : 37037 : : 44' 18" : 50' 38".

50' 38" X 88° 9'-J-10 = 7° 26'.
14°55' + 7°26' = 22°21'.

(10.) 75° 5'^ : 1 10° : : 51° 29'^ : 4° 42'.

90° : 4° 42' : : 7° 26' : 23'.
160° 43' — 23' =160° 20' : comp. 19° 40'.

(11.) sine 74° 5' .... 998302

sine 19°40' . . . . 952705

sine 18° 53' .... 951007

sine of comp. and rad. 19° 40' . . 1997390
tang, to comp. . . 74° 5' . . 945511

\',^^ tang 73° 9' . . 1051879

73° 9' + 22° 2l' = 95° 30' : comp. 84° 30'.

sine to comp. 18° 53' . . . . 997597
sine to comp. 84° 30' .... 898157

sine to comp. 84° 48' . . . . 895754
The complement to be used is 95° 12'.

(12.)

sine 22° 21' . .

. . 958008

sine 19° 40' . .

. . 952705

1910713

sine 84° 48' . .

. . 999821

sine 7° 23' . .

. . 910892

Sides. Angles.

(13.) 77° 41' 27° 6'

95° 12' 7° 23'

172° 53' : 34° 29' : : 77° 41' : 15° 29'.

7° 23'
15° 29'

22° 52' W.

Royal Astronomical Society. ,^ ^ ^tQ 5 1 9

which is the mean west declination at St. Helena for the pre-
sent year \S^9.

Mr. Glaisher, of Greenwich Observatory, kindly informs
me, that "a/ St. Helena^ IS^S, it was 23° 32' W., dectrasing
8' yearly."

Hence in 1849 it would have decreased about 32', leaving
the declination about 23° W., which is only 8' more than our
computation. Even this would probably diminish, if not en-
tirely vanish, could we obtain the mean declination for the
present year.

Manchester, Nov. 23, 1849.

LXIV. Pj'oceedi7igs of Learned Societies.

ROYAL ASTRONOMICAL SOCIETY.

[Continued from p. 391.]

Nov. 9, A PPEARANCE of Saturn's Ring, &c, in the Equatoreal
1849. ■^ of Cambridge, United States. By Professor Bond.

" During the period of the disappearance of Saturn's ring in 1848,
we often noticed breaks or inequalities in the ring, such as would
arise from irregularities in its structure, were the matter of which it
is composed unequally distributed in its different parts.

" Something of this kind has often before been observed, but
hitherto only on the illuminated side of the ring. That similar ap-
pearances present themselves also on the unilluminated side is a new
feature, important in its bearing on the true explanation of these
phaenomena,

" From June to September 1848 the light reflected from the edge
of the ring (the only part then visible), instead of being uniformly
distributed over a single line, was interrupted on each side of the
planet by spaces of some seconds in breadth, where it was barely
possible to trace the continuity of the edge. These inequalities were
sufficiently abrupt to render it difficult to distinguish at first sight
between them and the somewhat similar effects produced by either
of the small satellites being projected upon the ring ; their presence
could only be detected by their motion, of which the indications were
usually decisive in 15 or 20 minutes. On the other hand, the ir-
regularities of the ring always retained one fixed position with re-
ference to the ball, as long as the earth remained elevated above the
southern unilluminated surface.

" The same appearances were again presented between September
and January 1849, while the earth was elevated above the northern
unilluminated surface, in all this time retaining one fixed position with
respect to the ball.

" It is an unavoidable inference from our observations that these
breaks in the illumination of the edge do not rotate about the globe
of Saturn ; a result perfectly in accordance with what Schroeter has
established with regard to the corresponding irregularities on the
illuminated side.

520 lioyal Astronomical Society.

" The fact of these inequalities always retaining one unaltered po-
sition may be explained without precluding the possibility of a rajnd
rotation of the rings, by attributing them to the reflexion of the solar
rays from their inner edges. There seems to be no other way of ac-
counting for their being seen on both surfaces, both when illuminated
and when turned away from the sun.

" The first reappearance of the ring took place between August
31^'78, Greenwich M.T., and Sept. 3^-80; the second disappearance
between Sept. 12'*-80 and Sept 13'^-62 ; and the final reappearance
in 1849 between Jan. 18'i-47 and Jan. I9'^-43.

" On two or three occasions in the past year we have enjoyed the
sight of all the eight satellites at once.

"Our observations for a year or two past on the variations of the
brightness of Jupiter's satellites afford some curious results. Atten-
tion was first drawn to the subject in observing a transit of the third
satellite on the 6th of January, 1847. A few minutes after its en-
trance the satellite was visible on the disc just within the limit of
the planet, being brighter than the surrounding surface ; soon after
a dark spot, supposed to be the satellite, could just be discerned in
its place. The telescope used was an achromatic of 2|- inches aper-
ture, of excellent quality, but not powerful enough to enable us to
decide whether or not the spot was really the satellite.

" On the 28th of January, 1848, during the transit of the shadows
of the first and third satellites, the third satellite itself was seen with
the great refractor under very beautiful definition, as a black spot
between the two shadows, and not to be distinguished from them
except by the 2)lace it occupied. It was smaller than its shadow in
the proportion of 3 to 5, not duskish simply, but quite black like the
shadows. On the 11th of March it was again seen dark on the disc,
smaller than its shadow.

" On the 18th of March we watched the entire transit. At the
first internal contact the satellite -was distinctly seen on the disc,
brighter than Jupiter, though it had entered on a bright channel
south of one of the great equatoreal belts ; 20 minutes after it had
become nearly of the same brightness with the planet, so as to be
barely perceptible, yet still whiter than the surrounding surface.
While watching it with close attention, a minute dark speck sud-
denly made its appearance, in the place of the satellite, increasing
very rapidly till it occupied a space of about one second of arc in
diameter, quite black and nearly round, though an irregularity of
shape was suspected. Remaining thus for about two hours, tlie dark-
ness gradually lost its intensity, and quite disappeared before the
satellite left the disc. Something of this nature we have always ob-
served to accompany a transit of this satellite. The first and fourth
satellites we have also seen black or dusky on the disc, but the former
has once or twice crossed without our detecting any change. The
spots are always less than the shadows,but have appreciable diameters,
and make their appearance after the entrance of the satellite upon
the limb of Jupiter. Changes of relative brightness are constantly
going on ; the feeblest, on the average, being the fourth, and the
brightest usually the third.

Royal Astronomical Society. 521

" It would be well, as soon as Jupiter reaches a convenient position,
say during the ensuing winter and in the spring of 1850, for observers
generally to record their estimates of the relative brightness of the
satellites as often as possible. The labour of doing this will be but
trifling, and may lead to the discovery of the laws of these singular
phsenoniena.

" We have observed Schweitzer's comet twice since its reappear-
ance.

" From the circles of the great equatoreal compared with B. A. C.
No. 1634, we have —

Cambridge M.T. Comet's R.A. 1849-0 Comet's Decl. 1849'0

1849. hms hms o///

Aug. 24 15 37 30 4 45 0-4 -27 14 14

26 15 38 42 4 41 5-4 -27 17 45

" With the micrometer we have the following places : —

Cambridge M.T.
1849. hms m s / //

Aug. 24 15 37 30 Comet follows * in 0 34-75 Comet N. of * by 7 36-5
26 15 38 42 precedes * by 3 20-35 N. of * by 4 5-7

* is Lacaille 1613, whose place seems to be erroneous in N. P.D.

"The star Lalande 9167, of the 7'8 magnitude, is missing."

The Astronomer Royal exhibited an instrument for performing
arithmetical multiplications and divisions, constructed under the di-
rection of William Bell, Esq., Coronation Road, Bristol. The Pre-
sident remarked, that for mere exhibition of the significant figures
produced by a single multiplication or division, to a certain degree
of accuracy, nothing could be more convenient than the common
sliding rule containing two similar scales, one fixed and the other
moveable, in which the lengths corresponding to the numbers re-
presented are the logarithms of those numbers corresponding to a
certain modulus. In the scales of this kind in common use at the
Royal Observatory, the distance from 1 to 10 upon the scale is about
12 inches; and with these dimensions, a product or quotient will be
accurate, with the roughest degree of attention, to -g^ part ; an ac-
curacy which sufiices for a vast amount of the small calculations in
an observatory. And with proper scales for trigonometrical functions,
the problems of plane and spherical trigonometry can in most cases
be easily solved. These inconveniences, however, attend it : — 1st. It
cannot be conveniently applied to multiply three or more quantities,
or in general to exhibit a product of even two which is given in a
different denomination ; as when a sine is given by the product of
two tangents ; this failure, however, may usually be remedied by the
use of two parallel sliders. 2nd. When used to multiply numbers,
it gives no information as to the place of the decimal point in the
product. It is to remove some of these inconveniences, but espe-
cially the last, that Mr. Bell has constructed his instrument.

The logarithmic spaces in Mr. Bell's machine are arranged upon
a circle, a single series of numbers from 1 to 10 occupying the entire
circumference. This construction, as is well known, may be used
in the same way as the common sliding rule ; but, like it, it gives no

Royal Astronomical Society.

information as to the decimal point. But the revolving circle is
connected by toothed wheel- vt'ork with two smaller circles, each of
which performs one revolution for ten revolutions of the jjrincipal
circle, and each of which has upon its circumference ten series of
logarithmic numbers. These small circles, then, give us the means
of defining the decimal place, in multiplicand, in multiplier, and in
product. Thus, the successive figures 1 upon one circumference
may stand for -00001, -0001, -001, -01, '1, 1, 10, 100, 1000, 10000.
The rotating index of each circle is adjustable ; there are also ad-
justable indices on the fixed frame. Suppose, then, we had to mul-
tiply 27'42 by 332-6, we should, both in the principal circle and in
one of the smaller circles, set the 1 of the moveable circle or index
to 27-42 on the fixed circle; but there would be this diflference,
that on the principal circle we have no respect to the decimal point,
whereas on the smaller circle we should set to the 2742 following
the 10, Then for 332'6 we should turn the principal circle from 1
to 3326, but we should also turn it two complete revolutions, which
would carry the index of the second small circle from 1 to the 3326
following 100. Then the figures of the product will be exhibited very
accurately on the principal circle, and much less accurately on the
first of the small circles, but they would be found in that series of
numbers which follows 1000, and the place of the decimal point would
thus be exactly defined.

For the multiplication of three or more numbers, it is necessar)'^
to plant moveable indices after performing the first products ; this
process, however, is much less convenient than that with two sliding
scales in the sliding rule.

The Astronomer Royal remarked, that in his opinion this construc-
tion is too expensive and too cumbrous to be extensively used. But
he wished much to call the attention of members of the Society to
the use of the sliding rule, and to the peculiar defect which he had
indicated ; and to represent to them the great value of any simple
construction, which, while preserving the other advantages of the
sliding rule, would eflfectually remove that defect.

Mr. Drach suggests that a calculating machine, exhibited by Mr.
F. Schiereck in 1837 (the construction of which was concealed by
the inventor, who wanted 700/. for his secret), might probably be a
particular modification of the sliding rule applied to a circular form.
He also suggests the addition of other concentric circles to Mr. Bell's
scale, in which the trigonometric or other logarithmic numbers might
be laid down.

The Astronomer Royal gave an oral statement of the progress
made by Lord Rosse in the mounting of his 6-feet speculum.

In a lecture delivered on this subject by the Astronomer Royal in
November 1848, a detailed account was given of the distortions pro-
duced in the speculum by using the telescope at diflPerent inclinations
to the horizon, and of the explanation of these distortions suggested
by Lord Rosse, and also of the nature of the remedial measures tried
by Lord Rosse while the Astronomer Royal was at Parsonstown. It
will be sufficient to recall here, that when the edge of the speculum

Royal Astronomical Society. 52S

rested against short iron pillars fixed in the breech-piece of the tele-
scope, the firm hold produced by friction of the edge of the speculum
on the pillars, combined with the varying elasticity of the triangular
lever-supports in different inclinations of the telescope, caused
distortion of the mirror ; and that when, to avoid this friction, the
mirror was suspended (as regarded its edge-bearing), either by a
semicircular hoop or by a chain, a small difference in the edgewise
pressure, depending on a difference of inclination of the telescope,
threw some of the points of the supporting levers out of bearing, and
distortion of the mirror was produced. This latter fault arose from
the circumstance that the mirror could not slip freely over the points
of the supporting levers. To remedy this, the following arrange-
ment is now made. Each of the plates resting on the 27 supporting
points, instead of being partially attached to the mirror by a layer of
felt and pitch, is completely separated from it, to the distance of
about 1^ inch, and the speculum rests upon each plate by three
turned brass balls at the three angles of the plate ; so that the whole
surface of the speculum is now supported by eighty-one brass balls.
Each of these balls has a fine wire passing through a small hole in
the plate, and kept in tension by a weak spring on the opposite side ;
this prevents the ball from rolling away when the mirror is detached,
but allows entire freedom of motion to the ball, to the extent of about
one inch in any direction. Lord Ilosse has reason to think that this
construction is perfectly successful for its object. He has already
found that the speculum may be moved laterally half an inch without
the smallest discoverable distortion. Before the balls were used,
when the speculum was moved laterally -a^th of an inch, vision was
destroyed.

Lord Rosse thinks it, however, desirable to aiTange the edgewise
support, so that as little as possible may be trusted to the motion of
the balls. The lower semicircle of the edge is now to be gi'asped by
a strong iron hoop, very neatly fitted to it ; and the upper semicircle
is to have a thin hoop furnished with a drawing-screw or contracting
screw, merely for the purpose of bringing the strong hoop constantly
into fair contact with the edge of the mirror. And the ends of the
strong hoop (which are at the extremity of a horizontal diameter of
the mirror) are to be supported by rods, attached to a horizontal bar
which rests on the two upper pillars of the breech-piece, with the
utmost freedom of motion ; so that the mirror will be supported
edgewise by jimbals of the most perfect construction. Lord Rosse
hopes that, with this arrangement, in combination with the support
on the balls already described, the mounting of the mirror will be
sensibly perfect.

Lord Rosse had also communicated to the Astronomer Royal some
remarks upon the process of grinding large mirrors. With mir-
rors of 3 feet aperture there is not the smallest difficulty. In the
mirrors ground and polished by his apparatus, there is no appreciable
difference of focal length of the central part and the annulus next
the edge ; and this result is obtained uniformly. Still, with the
6-feet mirrors there is great difficulty. In all cases, a figure is ob-

524 Royal Astronomical Society.

tained which will do well for work ; rarely is one obtained which is
perfectly satisfactory. This arises in part from the impossibility of
testing the mirror while it is under the machine.

Adverting to Mr. Lassell's use of a wooden polisher, Lord Rosse
had stated to the Astronomer Royal, that he himself had at first used
a wooden polisher, but that he bad abandoned it, as there appeared
to be abundant evidence that the polisher was continually changing
its figure from the absorption of moisture. He considers it totally
inadmissible for very large specula. It will, however, probably be
necessary, with Mr. Lassell's apparatus, to use a light wooden po-
lisher, because it appears scarcely practicable in that apparatus to
apply a counterpoise.

In speaking of the results of observations with the large telescope.
Lord Rosse had stated to the Astronomer Royal that the nebula H.
131 exhibited a well-marked spiral structure, and that 2241 has a
central hollow.

Some Remarks on Falling Stars by Mr. Lowe*.
Mr. Lowe gives the following epochs when falling stars are said
to be abundant : —

April 22'! to 25'' Nov. 12^ to W^

July 17 .. 26 Nov. 27 . . 29

Aug. 9 .. 11 Dec. 6 .. 12

To which he adds from his own observation, Oct. 16*^ to 18'^.
There are many occurrences in January, but the days do not appear
to be fixed.

Mr. Lowe then states by whom observations have been made at
the foregoing epochs, and when and where.

The August epoch has been observed every year since 1841, and
is said by Mr. Lowe to be the most certain.

The November epoch, 12*^ to 14**, seems also well-fixed, but has
in late years been surpassed by the August epoch in brilliancy.

The epochs, Nov. 11^ to 29^*, and Dec. Q"^ to 12^ are somewhat
doubtful, so far as Mr. Lowe's observations extend.

The October epoch has been observed in 1843, 4, 6, 7 and 8, but
has not, so far as Mr. Lowe knows, been usually considered an
epoch.

On referring back the paths of meteors, it is found that a consider-
able number diverge from the same point in the heavens ; thus, du-
ring the July period of the present year, and up to the 9th of August,
the paths of the meteors, if produced backwards, would nearly meet
at a point to the east of a Cygni.

In 1848, of 80 meteors seen on August 19th, the paths of 55 were
recorded ; 23 came from Cygnus, 26 from Cassiopeia, and 6 were
discordant. In 1847 out of 13, 5 came from Cygnus and 8 from
Cassiopeia. This is confirmed by other observers. It seems very

* Further particulars will be found in the forthcoming Report of the
British Association, " Catalogue of Observations on Luminous Meteors,"
by Professor Powell ; and " Some Remarks on Luminous Meteors," by E.
J. Lowe, Esq.

Royal Astronomical Society. 525

probable that this divergence was merely apparent, and that the me-
teors were nearly parallel to each other.

On the 16th of August last, Mr. Lowe was surprised to see a
number of very small meteors, but brilliant for their size (being only
the apparent size of the smallest fixed star on a clear night), which
moved more slowly, and occupied a smaller portion of the heavens
than on the 10th, He attributes this difference to their greater
distance.

On the 10th of last August, Mr. Lowe observed that out of 55
meteors there were 1 1 cases in which one star followed another in
the same track nearly, and after an interval varying from 2 minutes
to 15 seconds. When a meteor follows another in the same path,
it has invariably been noticed that it also moves with the same speed.
From this circumstance, together with the fact that such meteors are
frequently very different in size, it may be supposed that tlie two
bodies are connected. If this be so, then a meteor at lO'' 29"" had
two attendants. This suggestion, if confirmed, would also show that
these bodies are material.

Mr. Lowe conceives that in our present state of knowledge of
these curious appearances, we might conveniently arrange them in
three classes : —

1st. Falling stars which leave luminous streaks behind them.

2nd. Stars which do not leave such streaks.

3rd. Luminous bodies, with defined discs.

The first probably shine by inherent light, for otherwise it is dif-
ficult to account for a luminous streak which lasts several seconds
(in some cases even minutes) after the meteor itself has disappeared.
The second may shine by reflected light, as described by Sir John
Lubbock, and the third are probably atmospheric, as they chiefly
move in discordant paths, are various in shape, and not unfrequently
change colour.

On the 8th of last August, at 10^ 16", a meteor of a conical
form, about twice the apparent size of a star of the first magnitude,
moved slowly in a horizontal direction from ^ Bootis, about 1 ° below
Arcturus (it left numerous sparks in its track). Here it suddenly
disappeared, and reappeared in about P and about 1°^ further on.
Thus it had moved in the same track, though invisible. On its re-
appearance it was neither so large nor so brilliant as before, and gave
the impression of a body moving rapidly and nearly directly /rom
the observer. It was orange-red, and was visible about 5* besides
the time of disappearance. The length of its path after its reappear-
ance was about 3°. The disappearance might be accounted for by
supposing the meteor to shine by borrowed light, and to have passed
through the umbra of some solid body. Sir John Lubbock suggests
that it may have passed through the shadow of the earth.

At Castle Lecky, Newtown- Linawady, county of Londonderry,
Mr. Webb saw (Nov. 1**, at ll'^ p.m.) in the north, a descending
meteor, which having fallen a considerable distance in an inclined
straight line diverged suddenly (to the west) on approaching towards
a dense cloud. The meteor described a curved path, concave to the
cloud, by which it was evidently diverted, and then disappeared.

526 Institution of Civil Engineers.

INSTITUTION OF CIVIL ENGINEERS.

Nov. 27, 1849.—" A description of the Old Southend Pier-head,
and the extension of the pier ; with an inquiry into the nature and
ravages of the Teredo navalis, and the means hitherto adopted for
preventing its attacks." By Mr. J. Paton.

After describing the form of construction of the old pier-head, and
showing the adoption of copper sheathing for protecting it from
decay, and the important considerations involved in the attempt to
preserve marine structures, the paper explained the ravages com-
mitted by marine worms {Teredo navalis, Limnoria terebrans, and
others) on the piles, both above and below the copper sheathingiJ
A general outline of the extension of the pier, and a minute descrip-
tion of the pier-head, were then given ; followed by an investigation
of the nature and operations of the Teredo navalis, which showed, as
a remarkable pecuharity, that no chemical means had hitherto pre-
vented wood from being destroyed by these animals and the Lim-
noria terebrans, whose destructive powers were likewise noticed, as
having penetrated between the copper sheathing and the wood at
Southend. The operations of the Teredo, although most destruc-
tive in warm climates, extended themselves to all places, having been
found almost in the Polar seas. The chief peculiarities which distin-
guished the Teredo were stated to have been ascertained by minute
microscopical investigation, and that woody fibres of an extremely
minute nature had been discovered in the body, thus setting at rest
the question as to whether the Teredo did actually feed upon the
wood. It was stated, that the failure of chemical means to preserve
timber from destruction by the marine worm was believed to proceed
from two causes, namely, of poisonous compounds having no seriously
injurious effect upon them, and the sea- water, and other things, de-
composing the poisonous ingredients contained in the wood.

In corroboration of the first of these views, accounts of experi-
ments made by Mr. Paton were adduced ; and physiological facts,
quoted from the British and Foreign Medical Review, were brought
forward to show that cold-blooded animals were much more tenacious
of life than those of a higher temperament ; and hence it was argued,
that as it required a very large quantity of poison of the most virulent
nature to destroy animals of a much higher order than the Teredo
navalis, it would take a still greater quantity to affect those animals
as they existed in their own element ; and it was questioned, under
these circumstances, whether wood could ever be so completely and
thoroughly saturated as in any degree to affect them.

The corrosive action of the sea- water, its extended influence and
constant variableness in diflferent parts of the globe, were then com-
mented on, and some of the various salts held in solution mentioned.
It was believed to be impossible to form any general notion of the
precise action of sea-water on timber, whether chemically saturated
or not, without a series of most minute experiments, and a large body
of facts carefully collected in different parts of the globe; as that
which might be advantageously used in the Thames might not be of

Institution of Civil Engineers. 527

the slightest avail in the Tropics, and vice versa ; it was thus ques-
tioned whether any generally applicable principle could be found for
the counteracting of that universal solvent of soluble matter.

The conclusions arrived at were, that the ravages of the marine
worm were not prevented by any chemical application, and that
nothing but mechanical means could ever prove completely success-
ful : studding with broad-headed nails was considered to be the most
effectual remedy, and various authorities were quoted, proving its
success. The paper concluded with a list of places where wood,
prepared with various chemical ingredients, had been destroyed from
various causes.

The discussion commenced by the Dean of Westminster, chiefly
remarking on the analogous action of the Pholas on stone, was
announced for continuation at the next meeting.

Dec. 4. — The discussion on Mr. Paton's paper extended to such
a length as to preclude the reading of any original communication.
Numerous specimens were exhibited, and commented on, of timber
thoroughly perforated by worms ; whilst beside them, under the same
circumstances, the " Jarrow wood" from Australia was shown to
have remained completely free from injury. The reference to the
age of Homer, as an instance of the ancient ravaging habits of the
Teredo, induced a return to geological questions ; and it was shown,
that in the London clay remains had repeatedly been found of
timber perforated by sea-worms. The oolite and greensand forma-
tions also exhibited petrified wood filled with boring moiluscae.
This led to the consideration of the formation most likely to with-
stand the attack of the Pholas ; and it was shown that the Portland
stone was, from the quantity of silica it contained, least liable to be
attacked. The Pholas was shown to have been in active operation
upon certain rocks from the earliest periods, but never upon Port-
land stone. Hence it was argued, that kind of stone should be used
for breakwaters and other works exposed to the action of the sea.

The early state of the Teredo was noticed ; when escaping from
the egg, in the shape of a free swimmer, it was drifted about with
the tide until it met with a log, a pile, or the side of a ship, to which
it attached itself, and making an inroad into it, became a non- loco-
motive animal of different form and habits, never again to leave
the habitation it had burrowed for itself in the body of the timber.
The question, of whether the boring operation of the marine worms
was carried on by chemical or by mechanical means, was lengthily
discussed. The thin shell, covered by its delicate membrane, was
instanced as not possessing strength enough to cut away timber;
but it was on the other hand shown, that the shape of the two shells,
forming the extremity of the animal, admirably adapted them for
powerful cutting or rasping tools, when moved rapidly in a circular
direction, as was evidently the case, from the uniformly cylindrical
character of the holes. The shells of the Pholas were also shown to
be used in that manner, and the opinion appeared generally to lean
to a mechanical cause for the effects observed. This bearing of the
discussion naturally induced remarks upon the ravages of the white

528 Itoyal Society,

ant of India ; which, however, appear to have been little studied,
and less understood, as far as attempting to arrest or to prevent its
inroads.

The various materials, such as Kyan's corrosive sublimate of men-
cury, Sir W. Burnett's chloride of zinc, Margary's salts of metals,
Payne's combination of muriate of lime and sulphate of iron, forming
in the timber an insoluble compound, and Bethell's creosote or oil
of coal tar, were discussed. All had their partisans, and were stated
to have succeeded and failed under certain circumstances. Speci-
mens of piles from Lowestoft harbour, whose waters were notoriously
full of worm, showed that timber in a natural state was in a few
months thoroughly perforated by Teredo in the centre, and Limnoria
on the surface ; but that piles which had been properly saturated
according to Bethell's system, in exhausted receivers, and subjected
to such pressure as ensured the absorption of about ten pounds' weight
of the creosote, or oil of coal tar, by each cubic foot of the timber,
were perfectly preserved from attacks of marine animals of any kind.
In one instance a partially " creosoted " pile had a notch cut into it,
deeper than the impregnation had extended ; a Teredo made its entry,
and was found to have worked in every direction, until it arrived
within the reach of the creosote, when the animal turned away and
eventually left the pile. Bethell's system was admitted, by all the
speakers, to be that which hitherto, after many years' exi)erience,
had afforded the most satisfactory results. Some most conclusive
experiments, instituted by Mr. Rendel at Southampton, were stated
to have produced the same results ; and at Leith all the piles were
weighed before and after their saturation, to ensure their absorbing
the full allowance of at least ten pounds per cubic foot.

ROYAL SOCIETY.
[Continued from p. 235.]

June 21, 1849, — "On the Anatomy and Affinities of the Family
of Medusae." By Henry Huxley, Esq. Communicated by the Bishop
of Norwich, F.R.S.

The author commences by remarking that no class of animals has
been so much investigated with so little satisfactory and comprehen-
sive result as the family of Medusce (including under that name the
Medusa:, Monostomatce and the Rhizostomidce), and proposes in this
paper to give a connected view of the whole class considered as
organized upon a given type, and an inquiry into its relations with
other families. This he has been enabled to do through numerous
and peculiar opportunities for the investigation of these animals,
enjoyed during a cruize of some months along the eastern coast of
Australia and in Bass's Strait*.

The memoir is divided into two sections, of which the first treats
of the anatomy of the Medusae, and the second of their affinities.

* Mr. Huxley is Assistant- Surgeon to H.M.S. Rattlesnake, now engaged on a
surveying voyage conducted by Capt. Stanley on the coasts of Australia and New
Guinea.

RoT/al Society. 529

The organs of the Medusae are formed out of two distinct mem-
branes— foundation membranes. Both are cellular, but the inner
is in general softer, less transparent and more richly ciliated than
the outer, but contains fewer thread-cells. The outer is dense,
transparent, and either distinctly cellular or developed into a mus-
cular membrane. It may be ciliated or not, and is usually thickly
beset with thread-cells, either scattered through its substance or con-
centrated upon more or less raised papillae developed from its sur-
face. When the stomach is attached to the disc, the outer mem-
brane passes into the general substance of the disc, while the inner
becomes continuous with the lining membrane of the canals. There
is a larger or smaller space, termed by the author the " common
cavity," between the inner aperture of the stomach and the openings
of the canals, with which both communicate. This is the structure
of the stomach in the Cryptocarpae and Phanerocarpae ; in the
Rhizostomidae it is fundamentally the same, but the stomachs are
very minute, and collected on the edges and extremities of the ra-
muscules — a common stem. The Rhizostomes, ^'woac? their digestive
system, have the same relation to the Monostome Medusae that the
Sertularian Polypes have to the Hydrag, or the Coralline Polypes to
the Actiniae. In consequence of a very irritable contractile mem-
brane surrounding and overlapping the orifices of their stomachs,
they are seen with difficulty. This membrane consists of two pro-
cesses, one from each side of the perforated edge of the branch. In
Rhizostoma they generally remain distinct, but in Cephea they are
frequently united in front of and behind each aperture so as to form
a distinct polype-like cell. In the structure of the disc there exists
no difference between the Monostome and Rhizostome Medusae.
The author gives an account of his observations on the minute struc-
ture of the disc. The arrangement of the cavities and canals of the
disc differs in the different sections. In very many of the Crypto-
carpae there is a circular, valvate, muscular membrane developed
from the inner and under edge of the disc. In the Phanerocarpae
such a membrane does not seem to be present, but in Rhizostoma
and Cephea it is evidently replaced by the inflexed edge of the disc.
In the Cryptocarpae the marginal corpuscles are sessile upon the cir-
cular vessel. They are spheroidal vesicles, containing a clear fluid,
and one or more strongly-refracting bodies occasionally included
within a delicate cell. The marginal vesicles are placed between
the inner and outer membranes of the circular vessel. In the Pha-
nerocarpae the marginal corpuscles are pedunculated and protected
by a semilunar fold. The author describes peculiarities in this part of
the organization of Rhizostoma. The excretory orifices, described
by Ehrenberg as general in Medusa aurita, were not detected by
the author in Cephea ocellata. Nor does he admit the supposed
nerves and intertentacular ganglia of that author to be such.

Paragraphs 29 to 36 are occupied by a minute description of the
tentacles of Medusae.

The generative organs of the three groups of Medusae are always
portions more or less developed of the walls of the system of canals,

Phil. Mag. S, 3. No. 239. Suppl. Vol. 35. 2 M

530 Royal Society,

and consist of the two "foundation " membranes, in or between which
the generative elements, whether ova or spermatozoa, are developed.
This the author concludes from his observations on several genera,
which he gives in detail, and which add considerably to, and differ
in some respects materially from, what has been stated by previous
observers. In the ovarium, the two membranes develope between
them immense multitudes of ova with a dark granulous yelk and
clear germinal vesicle. The ova are attached to the outer surface
of the inner membrane. In the testis the inner membrane is pro-
duced into a vast number of thick pyriform sacs, which lie between
the two membranes, with their blind ends towards the inner surface
of the outer membrane; internally, they open each by a distinct
aperture on the fine surface of the inner membrane. The contents
of the sacs are spermatozoa, and cells in every stage of development
towards spermatozoa, which appear to be formed by the elongation
of the secondary cells contained in the large cells.

The author's observations lead him to believe that the muscular
fibres are always developed in the outer "foundation" membrane.
Each fibre in Rhizostoma is made up of very small and indistinct
fibrils, which are transversely striated. He has not observed any
indubitable trace of a nervous system in the Medusae, nor of the
so-called blood-vascular system described by Will.

In this section of the memoir the affinities of the Medusae are
Considered. In their essential characters, — viz. their construction
out of two membranes inclosing a variously -shaped cavity ; their
generative organs being external and variously developed pro-
cesses of the two membranes ; and the universal presence of the
peculiar organs called thread-cells, — they present a striking resem-
blance to other families of Zoophytes, as the Hydroid and Sertula-
rian Polypes, the Physophoridge and the Diphydae. The disc of a
Medusa is represented by the natatorial organ among the Diphydae
and Physophoridae, but has no homologue among the Hydrae and
Sertulariae. The cell of the Sertularian Polype rather resembles the
" bract " of the Diphydae than the natatorial organ, and the latter
family forms a connecting link between the Medusae and the Phy-
sophoridae. Of the two kinds of tentacles in the Medusae, the first
is represented in the Physophoridae and Diphydae, by the thickenings,
richly beset with thread-cells, that frequently occur in the lip of the
stomach ; in the Sertularian Polypes by the tentacles of the margin
of the mouth. The second kind is homologous with the prehensile
organs of the Diphydce and Physophorida, and with the peculiar
clavate processes of Plumularia. All these organs commence their
development as bud-like processes of the two joining membranes.
The peculiar clavate organs of Plumularia are developed from the
common tube independently of the stomach. They have not been
hitherto described, and were observed by the author in two species
of Plumularia dredged at Port Curtis. They were of two kinds, the
one attached to the cell of the polype, the other to the pedicle of the
ovary. To each species there were three processes of the former
kind, two above proceeding from near that edge of the aperture

Eoyal Society. 531

which is towards the stem, the other below from the front part of
the base of the cell. They were conical in one species, club-shaped
and articulated in the other, and consisted of an external horny
membrane open at the apex, and an internal delicate membrane in-
closing a cavity, all these being continuous with the corresponding
parts of the stem. At the apex of each, and capable of being pressed
through the aperture, lay a number of thread-cells. The second
kind of organ was present in the species with conical processes. It
consisted of a stem proceeding from the pedicle of the ovary, bearing
a series of conical bodies, having the same constitution as those just
described ; the whole bearing a close resemblance to the prehensile
organs of the Diphydae.

The following table exhibits the homologies of the several families,
which must be regarded as by no means so distinct as hitherto sup-
posed, but rather as members of one great group, organized upon
one simple and uniform plan, and even in their most complex and
aberrant forms reducible to the same type.

Stomachs identical in Structure throughout.
Medusae. Physophoridcs. Diphydae. Sertularidm. Hydra.

Disc Natatorial organ .... Natatorial organ.

_ , f Canals of natatorial ) Canals of natatorial

Canal* 1 organ / organ.

Common cavity . . ") , oo/.n„i„u a,,A „nm i

Canals of branches Common tube . . . . { ^^ tube ) ^'^'^'^^'^ "^ **^^'"-

(Hhiz.) J

Bract Polype-cell.

.^.>~

Tentacles,! {''^^oS .^''^."5} Qval tentacles.

2 Prehensile organs Clavate organs .... Tentacles (?).

C Generative sac Generative organ.. . Generative organ<

Generative organs < Natatorial organ of I j Natatorial organs

L generative sac . . / ' " " I (Coryne).

Marginal vescicle ? ? ?

"On the Microscopic Structure of the Scales and Dermal
Teeth of some Ganoid and Placoid Fish." By W. C. Williamson,
Esq. Communicated by Edwin Lankester, M.D., F.R.S.

The author commences his paper by stating that the structure
and modes of growth of fish-scales have been studied by many ob-
servers, especially by Leeuwehhoek, Agassiz, Mandl and Owen.
The first of these considered each scale to consist of numerous
superimposed laminae added successively to the inferior surface.
This view has been revived, with some important modifications, by
M. Agassiz, and especially applied to the scales of ganoid fish;
which he showed to consist of laminae of true bone, usually
covered with enamel (email), the latter often resembling the den-
tine of fishes' teeth. M. Mandl denied that ganoid scales had
been formed by such successive additions of laminae ; and Professor
Owen also opposed the idea, that they had merely been the result of
successively excreted deposition. The author then proceeds to the
examination of the scales of the following genera and species : —
Lepidosteus osseus, Lepidotus semiserratus, L. Mant^lli, and L.fitn,"
briatus, Seminotus rhombifer, Pholidotus Leachii, Ptycholepis BoU

2 M 2

532 Royal Society^^ -

lensis, Beryx, Dapidhis orhis, and D, grannlosus ; all of which ap-
pear to be constructed according to a common type — one singular
modification of which is seen in Palceoniscus comptus and P. Beau-
monti, and another in Gyrodus and Aspidorhynchus acutirostris.
Still more elaborate complications occur in the scales of the Stur-
geon' and of Platysomus parvulus, the minute structure of which
is described. Then follow detailed accounts of another interesting
group of structures found in the genera Megalichthys, Holoptychkts
and Diplopterus, in which the osseous tissues and their superficial
coverings are exceedingly beautiful and complicated. The next fish
examined is Macropoma Mantelli from the chalk. In this the true
bony operculum is studded over with dermal teeth, as is also the
posterior part of each scale; the portion of the latter, however,
which is subjacent to these dermal teeth, is not osseous, but consists
of thin laminas, which do not contain lacunae. The hollow viscus
found in the interior of the Macropoma, is shown to be a cylinder
of true osseous tissue, of a singular laminated structure full of lacunas.
The author rejects the idea of its having been a stomach, but thinks
that it may have served the purpose of an air-bladder.

The structure and arrangement of the dermal teeth from the skin
of the Dog-fish are then investigated, and appear to resemble those
on the opercular bones and scales of Macrojjoma. Similar teeth are
described in the fossil skin of Hyhodus reticulatus, from the lias of
Lyme Regis. In the latter, numerous small granules of calcareous
matter, having a concentric laminated structure, have been im-
bedded in the substance of the soft cutis, under the dermal teeth.
The corresponding dermal teeth from the Raia clavata are described,
and also those covering the snout of tlie common Saw-fish ; as well
as the very singular premaxillary bones of the Ccelorhynchus.

From an examination of the dermal appendages of the fishes thus
cursorily enumerated, the author concludes —

That what has hitherto been termed enamel, is in fishes a cottii-''
pound structure, separable into ganoin and kosmine (Kocr/ieiv, to
adorii) ; the former being transparent and laminated, but otherwise
structureless, whilst the latter consists of minute branching tubes re-
sembling the dentine of true teeth.

That the kosmine covering the osseous scales of so many ganoid
fish, as in Lepidotus semiserratus, Megalichthys Hibherti, &c., is
homologous and identical with the substance composing the dermal,
teeth of the true placoids, such as the Dog-fish, Thornback, &c.,
only that, whilst in the former the areolae of kosmine are aggregated
upon bony scales, in the latter they are implanted in the soft integu-
ment, witliout the intervention of any bony matter. It follows from
this, that the distinction of " ganoid " and " placoid " is scarcely a
physiological one, inasmuch as the scales of many so-called ganoid
fish, such as Dapidius orbis, Acipenser, &c., exhibit little or no trace
of either ganoin or kosmine; that in many of the Placoids these sub-
stances are very largely developed ; and that a series of well-defined
links exist, passing through the common Thornback, the common
Spotted Dog-fish, Hyhodus reticulatus, Macropoma Mantelli^ Da-

Royal Society, w 533

pidius granulosus, HoloptycJdus, Diphpterus and Megalic/Uhys, Xt^,;^
whicli the ganoid and placoid forms merge in one anotlier. . ,,

That ganoid scales consist of variously modified osseous lamellae,
the result of successive additions made chiefly to the lower surface .
of each ; but also, under particular circumstances, either to a partnH
or to the whole of the upper surface.

That these lamellte have not been the result of any process of
excretion, or depositions from a secreting surface, as supposed by
M. Agassiz, but that they have been formed by the calcification of
the lower laminae of an investing vascular periosteum ; and that
consequently the phagnomena attending the structure and growth of
these ganoid scales contribute in a material degree to establish the
correctness of the views recently promulgated by Professor Sharpey
respecting the growth and development of human bone ; the gra-
dual formation of Haversian canalsj being traced with great ease
from the simple laminae seen in the scales of Lepidosteus, Lepidotus,
&c., through Aspidorhynchtis, Acipenser, Holoptijchius, &c. to their
high degree of development in Megalickthys.

That the study of the microscopic structure of the dermal ap-
pendages offish may, when carried on with due caution, be made a
valuable auxiliary, both in distinguishing between allied species, and
in establishing the existence of important affinities, even when ap-
plied to otherwise insignificant fragments ; but that it is capable of
being overstrained, and of leading to erroneous conclusions, if any
classifications are founded upon it irrespective of the other portions
of the fish to which the scales belong, because of the unequal ratio
in which the various parts of an organism may have been developed.
Thus, whilst Lepidosteus osseus presents one of the simplest forms
of ganoid scales, it has the concavo-convex vertebral articulations of
the Ophidians ; on the other hand, in many species, as in Megalick-
thys and Holoptychius, whilst the structure of each part of the exo-
skeleton is highly developed, the vertebras appear to have the double
concave articulation common amongst fish and enaliosaurs.

The author, in coe elusion, acknowledges his obligations to Sir
Philip M. de Grey Egerton, M.P., Dr. Mantell, Mr. Binney, Mr.
J. E. Gray and Mr. Searles Wood, for their valuable co-operation
in supplying many important specimens for examination.

** On the Mechanical Equivalent of Heat." By J. P. Joule,
Cor. Associate R. Acad. Sciences, Turin, &c. Communicated by
M. Faraday, D.C.L., F.R.S., Foreign Memb. Acad, of Sciences,
Paris, &c.

After passing in review the experimental researches of Rurnford,
Davy, Dulong, Faraday, and others who have successively discovered
facts tending to prove that heat is not a substance, but a mode of
force, the author mentions the papers he has already communicated
to the Royal Society, and published in the Philosophical Magazine,
in which he has endeavoured to show that in the production of heat
by the expenditure of force, and vice versa, in the production of
force by the expenditure of heat, a constant relation always subsists
between the two. This relation he denominates the '* Mechanical

5S4j Royal Society,

Equivalent of Heat," and the object of the present paper is to advance
fresh proofs of its existence, and to give to it the numerical accuracy
requisite to fit it as a starting-point for further incjuiries.

In carrying out the above design, the author has determined the
relation of work done to heat produced in the cases of the friction, —
1st, of water; 2nd, of mercury ; and 3rd, of cast iron.

In the experiments on the friction of the fluids, the liquid was
contained in a covered cylindrical vessel of copper or iron, and the
agitation was effected by vanes of brass or iron, fixed to a vertical
axis revolving in the centre of the vessel, whilst fixed vanes pre-
vented the liquid being whirled in the direction of rotation. In the
experiments on the friction of solids, a disc of cast iron was rotated
against another disc of cast iron pressed against it ; the whole being
immersed in a cast-iron vessel filled with mercury.

The force expended was measured by the descent of the weights
employed in rotating the apparatus ; and great care was taken to
correct it for the friction of the axes of the pullies employed, &c.

The heat evolved by the friction was measured by exact thermo-
meters, and very laborious precautions were taken in order to elimi-
nate the effects of radiation or conduction of heat to and from the
surrounding atmosphere. The corrected thermometric effect was
then reduced to a known capacity for heat, by means of extensive
series of experiments made in order to ascertain the specific heat of
the materials in which the thermometric effect was observed.

In this way the number of units of work, estimated in pounds one
foot high, required to be done in order to develope one degree Fahr.
in one pound of water taken at about 50°, was found to be as
follows : —

772*692 from friction of water, a mean of 40 experiments.
774''083 from friction of mercury, a mean of SO experiments.
774'-987 from friction of cast iron, a mean of 20 experiments.

"On the Nitrogenous Principles of Vegetables as the sources
of artificial Alkaloids." By John Stenhouse, F.R.S.

After observing that there are i'evf departments in organic che-
mistry which during the last six or seven years have attracted more
of the attention of experimenters than the artificial formation of the
alkaloids, and attributing this fact to the interesting nature of this
class of bodies both as regards their well-defined chemical properties
and the important medical virtues which many of them possess, the
author proceeds to state, that although attempts to form the natural
alkaloids, such as quinine, cinchonine, &c., by artificial means have
hitherto been unsuccessful, yet chemists have been enabled by various
processes to procure artificially a considerable number of true alka-
loids very analogous to those which occur in nature. The various
methods by which this has been effected, such as by acting on essen-
tial oils with ammonia, by the destructive distillation of coal and
animal substances, &c., are then enumerated and described.

It is also remarked as somewhat singular, that while so many other
sources have been examined, no attempt should have been made to
procure alkaloids from vegetable albumen, fibrine, caseine, &c., which

lioyal Society, 535

are so rich in nitrogen, and which occur in such abundance in many-
plants. What renders the neglect of these substances the more re-
markable, is the consideration that coal has been one of the most
productive sources of the alkaloids, yielding them, as it does, four
other bases besides ammonia. Now as coal is universally admitted
to be of vegetable origin, and to consist of the remains of a variety
of extinct vegetables, the nitrogenous principles of which must be
regarded as the sources of the bases which it yields, it seemed to the
author not unreasonable to expect, that, by acting on the nitrogenous
principles of recent vegetables, the same organic bases as those ob-
tained from coal, or at any rate a series of analogous bases, would be
obtained in still greater abundance; and it subsequently appeared that
this latter expectation was not altogether without foundation.

From the difficulty of procuring vegetable albumen, fibrine, &c.
in a state of even tolerable purity, those portions of plants (usually
their seeds) were selected which contain those principles in the greatest
abundance.

In the first instance, a quantity of Phaseolus communis, or common
horse-bean, was destructively distilled in a cast-iron cylinder, and
the products collected by means of a large condensing Liebig's appa-
ratus. These products closely resembled those obtained from the
distillation of bones and other animal matters, comprising among
other substances acetic acid, empyreumatic oils, tar, a great deal of
ammonia and several organic alkaloids. The crude product was super-
saturated with muriatic acid, and the clear liquid decanted after the
tar had subsided. The acid liquor was next passed through a cloth
filter, which removed the greater portion of the resinous matter.
The clear liquid was then poured into a capacious still, and super-
saturated with carbonate of soda. When the liquid began to boil,
much ammonia was disengaged, and a quantity of oily bases col-
lected in the receiver. Their amount increased as the distillation
proceeded. These bases were separated from the ammoniacal liquid
by means of a pipette, and were purified by suitable processes which
it is unnecessary to particularize. These bases, though they were
found to vary very considerably in their boiling-points and some of
their properties, were very similar in other respects. They were
transparent colourless oils, which were all of them lighter than water,
and refracted the light strongly. Their taste was hot, resembling
that of oil of peppermint. They all exhibited strong alkaline re-
actions, and neutralized the acids perfectly, forming crystallizable
salts. The most curious circumstance respecting them was, that they
were apparently quite different from the series of bases obtained
from either bones or coal, and contained no aniline.

One of these bases was isolated and subjected to analysis. It
boiled between 150° and 155° C. Its formula was found to be
Cjo H,; N, which differs only by two equivalents of hydrogen from
nicotine. The only obstacle which has hitherto prevented the se-
paration and examination of each of these bases individually, has
arisen from the difficulty of procuring them in sufficient quantity.
Not that beans when distilled yield bases in so much smaller quan-

3$6 Royal Society,

tities than bones and other animal substances ; but as both bones and
coal are distilled on the largest scale for commercial purposes, their
crude oils may be easily procured in any quantity, and from these
their respective series of bases may be readily prepared. In regard
to the bases from beans and other seeds, the case is quite different ;
as the scientific chemist is compelled to distil these substances on
purpose, an operation which cannot be conveniently conducted in a
laboratory, as it requires an apparatus so large as to be almost upon
a manufacturing scale.

Oil-cake. — As the Phaseolus commimis was regarded as the type
of the Leguminosie, oil-cake, or the expressed seeds of L'mum usita-
tissimum, was selected from that numerous class of plants in which
the starch of the Graminese is replaced by oil. The products of its
distillation were very similar to those from beans, containing how-
ever more ammonia and a somewhat smaller proportion of oily bases,
which, though similar, appeared to differ from those of the pre-
ceding series. They were also equally devoid of aniline.

Wheat, Triticum hybernum, and subsequently peat from the
neighbourhood of Glasgow, were also destructively distilled. Both
of these substances, in addition to ammonia, yielded a series of oiiy
bases, which also contained no aniline.

Distillation ofviood, — The author proceeds to state, that through
the kindness of an extensive pyroligneous acid manufacturer he
"was enabled to examine considerable quantities of the crude acid
liquor obtained from the destructive distillation of beech, oak, and
other hard woods. The stems and larger branches of trees are alone
employed for this purpose. He found to his surprise that this acid
liquor contained scarcely a trace of ammonia or of any other organic
base, showing that the woody portions of the limbs and stems of
trees are nearly devoid of nitrogenous matter, in which respect they
differ extremely from peat, which in general contains two per cent,
of nitrogen ; and he considers this circumstance as perhaps calculated
to throw some light upon the origin of the coal-beds, Avhich some
geologists believe to have been formed from the submersion of
forests and the floating of uprooted timber into estuaries and lakes,
while others contend that they have been produced by the submersion
of beds of peat. Irrespective therefore of other considerations, the
author urges in favour of the latter opinion, that wood is not capable
of furnishing the amount of nitrogen we find existing in coal, while
peat contains rather more than double the quantity required. The
expectation of procuring aniline, picoline, &c., the coal series of bases,
from the distillation of peat, was disappointed ; a result only to be
accounted for on the hypothesis, that the different genera of plants,
when destructively distilled, yield different series of organic bases.

From the facts which have pi'eviously been stated, the author con-
siders himself warranted in concluding that when ammonia is pro-
duced by the destructive distillation of either animal or vegetable sub-
stances, it is always accompanied with the formation of organic
bases. Now as ammonia is known to be procurable from these sub-
stances by other methods than destructive distillation, it seemed

Royal Society, 53V

highly probable that on these occasions organic bases would also be
produced. Beans, oil-cake and flesh, were therefore successively
boiled in a distilling apparatus with strong alkaline lyes. In every
instance, in addition to ammonia, a series of organic bases was also
produced. Similar results were also obtained when the above-men-
tioned substances were digested in strong sulphuric acid, the acid
solution supersaturated with an alkali and subjected to distillation.
The ammoniacal liquor which passed into the receiver was found
invariably to contain organic bases.

Bases by putrefaction. — As putrefaction is almost the only other
means by which ammonia is readily procurable in quantity from
vegetable and animal substances, the effects of this process were also
examined in the first instance in the case of guano. An aqueous
solution of Peruvian guano was saturated with carbonate of soda
and distilled. In addition to much ammonia, a quantity of basic oils
was also obtained. Subsequent to this experiment the effects of putre-
faction on a quantity of horse-flesh were also examined, when a con-
siderable amount of oily bases was found to have been generated.

From the facts which have now been enumerated, the author con-
cludes '■^that whenever ammonia is generated in large quantity from
complex animal or vegetable substances, it is invariably accompanied
by the formation of a larger or a smaller amount of volatile organic
bases." If therefore researches similar to the present are actively
prosecuted, and if the seeds and leaves of the various genera of plants
are subjected to these or analogous processes, it seems not unreason-
able to expect that the number of the organic alkaloids will ere long
be considerably increased.

"On the Development and Varieties of the Great Anterior
Veins in Man and Mammalia." By John Marshall, Esq. Commu-
nicated by Professor Sharpey, F.R.S.

The object of this paper is to state the result of observations on
the metamorphosis of the great anterior veins in Man and Mam-
malia, and on the relations existing between the primitive and final
condition of these vessels, in different cases, both in their normal
arrangement in animals, and their abnormal condition in the human
subject.^

From an examination of the form and structure of the sinus of the
great coronary vein, and of the arrangement of its branches and
valves in Man and some of the Mammalia, and from a comparison
of those parts with the terminations of the great coronary and other
posterior cardiac veins in the other Mammalia, the coronary sinus
in Man and one set of Mammals, as the Dog, Cat, and Seal, is shown
to be analogous to the loiver part of the left vena cava anterior found
in another set, represented by the Elephant, Rabbit and Hedgehog,
and to the lower part of the left vena azygos, found in a third set, as
exemplified in the Sheep, Ox and Pig. The great coronary vein,
therefore, is shown always to end in a similar way, viz. in a larger
muscular venous channel, which, in all cases, ends in the right auri-
cle of the heart, by a wide orifice situated in an exactly correspond-
ing part of that cavity.

5S8 Royal Society,

The author remarks that a similar view has recently been published
by Bardsleben ; but his own observations were completed, and his
deductions arrived at, quite independently.

Reflecting on the above-mentioned analogies and on the known
method of development of the great anterior veins in all the Verte-
brata, as pointed out by Rathke, from four primitive lateral venous
trunks, viz. two anterior or jugular, and two posterior or cardinal
veins, the coronary sinus is demonstrated to be the lower persistent
portion of the left anterior primitive venous trunk, next to the heart.
By Rathke, however, the whole of this left primitive trunk, from the
neck down to the heart, is supposed to become occluded and then
entirely to disappear in Man, and in such animals as are similarly
formed in respect to these great veins ; but the author finds that not
only does its lower part persist in a previous condition as the coro-
nary sinus, but that other remnants or vestiges of this primitive ve-
nous channel are to be found throughout life in Man, and in those
animals in which the great anterior veins undergo a like metamor-
phosis.

The inquiry thus opened is then systematically pursued, first, by
tracing the details of the metamorphosis of the great anterior veins
in the embryos of the Sheep and Guinea Pig, and in the human foetus ;
secondly, by a comparison of the adult condition of these great veins
in the entire class of Mammalia; and thirdly, by an examination of
the occasional varieties of the same vessels met with in the human
subject.

1. Of the development of the great anterior veins. — After describing
at length the metamorphosis of these vessels, the author proceeds to
give an account of the remnants of the left anterior primitive vein
in the adult.

These are indicated by the following parts, traced from the sum-
mit of the left thoracic cavity down to the back of the heart. Out-
side the pericardium certain fine bands of fibrous tissue, which descend
beneath the pleura, from the trunk of the left superior intercostal
vein to the front of the root of the left lung ; and inside the peri-
cardium, a fold of the serous membrane which passes down from the
left pulmonary artery to the subjacent pulmonary vein, — certain
opaque lines or streaks upon the side and back of the left auricle, —
a small oblique auricular vein which is continued from those streaks
down to the coronary sinus, — and lastly, the coronary sinus itself.
The fold of the pericardium, which hitherto has escaped observation,
is particularly described. It is named by the author the vestigial
fold of the pericardium, or, from its having contained the canal of
Cuvier in the embryo, the Cuvierian fold.

2. Under the second head, a comparison is instituted between the
great anterior veins of Man and the Mammalia generally.

Having remarked that, as high up in the vertebrate scale as Birds,
no fundamental alteration occurs from the primitive condition of two
anterior and two posterior independent lateral venous trunks, the
author remarks that in all Mammalia one characteristic change is
met with, viz. the formation of a transverse branch across the root of
the neck.

Royal Society. SS9

The right anterior primitive vein in all cases persists as the right
or ordinary vena cava superior ; but the left vein either remains un-
occluded, and returns the blood from the left side of the head and
neck, from the left upper limb, the left side of the thorax, and from
the substance of the heart; or, owing to a partial occlusion, returns
only the blood from the left side of the thorax and from the substance
of the heart ; or, owing to still further occlusion, from the substance
of the heart alone. Hence three principal groups arise.

a. In the first group a right and a left superior vena cava exist,
connected by a cross branch at the root of the neck, as in the Mono-
tremata, Marsupialia, the Elephant, most Rodentia, the Hedgehog
and the Bat.

b. In another group a right superior cava and a left vena azygos
exist, as in the Sheep, Goat, Ox, Pig, Horse, Mole and Guinea Pig.

c. In the third group there is found, besides the right vena cava
superior, only a left cardiac venous trunk or coronary sinus, together
with the vestiges already described, as in the Cetacea, Carnivora and
Quadrumana, as well as in Man.

In each of these groups subordinate varieties are shown and clas-
sified.

3. The almost numberless varieties of the great anterior veins in the
human subject are then arranged on principles similar to those adopted
in regard to the different conditions found among Mammalia ; but
the groups are arranged in the inverse order, and the usual con-
dition of the veins in Man is included as a necessary element in the
series.

In one large class of cases, comprehending three groups similar to
those of the different Mammalia already defined, the cross branch in
the neck is always present.

g,. In the first group there is a right vena cava superior, and a left
cardiac venous trunk or coronary sinus. This is the ordinary con-
dition. Further subdivisions arise, depending on peculiarities of the
vena cava itself, which are rare; of the azygos system, which are
exceedingly numerous; and of the coronary vein and sinus, which
are again uncommon. Transposition occasionally produces a further
modification, in which the superior cava is found on the left side;
whilst the coronary sinus, the oblique vein and the vestigial fold of
the pericardium, exist on the right.

b. Ill another group there might exist a right vena cava superior
and a left vena azygos, as in the Sheep ; but no example of this pos-
sible variety has yet been met with in the human subject.

c. In the third group a right and a left superior cava coexist, as
in the Elephant, constituting what is termed a double vena cava su-
perior. Thirty examples of this condition are adduced, of which
eleven only have occurred in adult and otherwise perfect hearts.
One of these was met with by the author, and is specially described.

Lastly, a separate or second class consists of those cases in which
the cross branch is wanting, and which are, accordingly, destitute of
the characteristic mammalian type, and present, as in Birds, the per-
sistent condition of four independent lateral venous trunks.

The paper is illustrated by original drawings, of the development

ii6 Bxiyal Society.

of the veins in the Sheep and in Man, of the vestiges of tlie left pri-'
niitive vein ordinarily found in the adult human subject, and of the'
fresh example of double vena cava superior in Man met with by the
author.

" A Mathematical Theory of Magnetism." By William Thomson^
M.A., F.R.S.E , Fellow of St. Peter's College, Cambridge, and Pro-
fessor of Natural Philosophy in the University of Glasgow.

The theory of magnetism was first mathematically treated in a
complete form by Poisson, Brief sketches of his theory, with some
simplifications, have been given by Green and Murphy in their works
on Electricity and Magnetism. In all these writings a hypothesis
of tM'O magnetic fluids has been adopted, and strictly adhered to
throughout. No physical evidence can be adduced in support of
such a hypothesis ; but on the contrary, recent discoveries, especially
in electro-magnetism, render it extremely improbable. Hence it is
of importance that all reasoning with reference to magnetism should
be conducted without assuming the existence of those hypothetical
fluids.

The writer of the present paper endeavours to show that a com-
plete mathematical theory of magnetism may be established upon
the sole foundation of facts generally known, and Coulomb's special
experimental researches. The positive parts of this theory agree
with those of Poisson's mathematical theory, and consequently the
elementary mathematical formulae coincide with those which have
been previously given by Poisson.

The paper at present laid before the Royal Society is restricted to
the elements of the mathematical theory, exclusively of those parts
in which the phenomena of magnetic induction are considered.

The author hopes to have the honour of laying before the Society
a continuation, containing some original mathematical investigations
on magnetic distributions, and a theory of induction, in ferro-
magnetic or diamagnetic substances.

" On the Structure of the Dental Tissues of Marsupial Ani-
mals, and more especially of the Enamel." By John Tomes, Esq.
Communicated by Dr. Grant, F.R.S.

The author of the communication bearing the above title, after
examining microscopically the teeth of many marsupial animals taken
from the majority of the families that make up the order Marsupialia,
finds that they possess a structural character by which they may be
distinguished from other mammalian teeth, subject only to one. or
two exceptions; in which exceptions, however, the teeth are small,
and may readily be distinguished from marsupial by their external
character. They are the teeth of the Hyrax Capensis, the British
Shrews, and the molar teeth of the Jerboa.

The author states, that so far as he has had opportunities of ex-
amination, the teeth of the various species may also be distinguished,
the one from the other. He points out, for instance, that, on com-
parison, the teeth of Dasyurus ursinus may be distinguished from
the D, macrourus.

The peculiar characteristic of marsupial teeth exists iu the con-

Royal Society, 54-1

tinuation of the dentinal tubes into the enamel ; so far as the author
has investigated them, he finds but one exception, and that in the
Wombat, — the representative of the rodents in the marsupial order.
This creature, he finds, has teeth that are nearly allied in structure
as well as external form to the teeth of rodents, and more especially
to the Hare and Rabbit.

The author states, that he has observed that the dentinal tubes in
the human and other teeth are sometimes continued for a short
distance into the enamel. This he considers a rudimentary condi-
tion which is fully developed in the marsupial teeth. The author
observes that the dentinal and enamel pulp become firmly united to
each other previous to the commencement of calcification in either,
and that it is highly probable that the linear columns of the two
pulps are joined end to end, and that the columns of the enamel pulp
so joined become developed into tubes instead of into solid enamel
fibres. He considers this the more probable, as he has observed
that the enamel fibres in an early stage of development are partially
tubular in the teeth of several animals whose enamel fibres are ulti-
mately solid.

The teeth described and figured are those of the —

Macropus giganteus. Petaurus sciureus.

Hypsiprymnus penicillatus. Dasyurus macrourus.

minor. ursinus.

y.^ Phalangista vulpina. Thylacinus cynocephalus.

Wombat. Didelphis virginiana.
Petaurus taguanoides.

The author considers that the facts stated in his paper justify two
conclusions of a general character. First, that the existence of pro-
longed and fully-developed tubes in the enamel, continuous with
those of the subjacent dentine, is common to the great majority, if
not all, of the marsupial animals, excepting the Wombat. And, se-
condly, that the enamel and dentine are so closely related, that they
should be regarded as modifications of each other, rather than as
tissues of a wholly different nature.

" On the Motion of Gases." — Part H. By Thomas Graham,
F.R.S. &c.

The experiments of the former paper by the author on the same
subject, afforded grounds for assuming the existence of a relation in
the transpirability of different gases, that is, their passage through
capillary tubes of an equally simple nature as that which is recog-
nized among the specific gravities of gases, or even as the still more
simple ratios of their combining volumes. Compared with solids
and liquids, matter in the form of gas is susceptible of small variation
in physical properties, and exhibits only a few grand features. These
differences of property, which are preserved amidst the prevailing
uniformity of gases, may well be supposed to be among the most
deep-seated and fundamental in their nature with which matter is
endowed. Under such impressions he has devoted an unusual
amount of time and attention to the determination of this class of

64)2 Royal Society.

numerical constants. As the results, too, were entirely novel, and
wholly unprovided for in the received view of the gaseous constitu-
tion, of which indeed they prove the incompleteness, it was the more
necessary to verify every fact with the greatest care.

The most general and simple of the results is, that the transpira-
tion velocity of hydrogen gas is exactly double that of nitrogen gas.
These gases, it will be remembered, have a less simple relation in
density, namely 1 to l^. This was the conclusion respecting the
transpiration of these gases of his former paper, and he has obtained
since much new evidence in its favour. The transpirability of car*
bonic oxide, like the specific gravity of that gas, appears also to be
identical with that of nitrogen.

The result which may be placed next in point oif accuracy and
importance is, that the transpiration velocity of oxygen is related to
that of nitrogen in the inverse ratio of the densities of these gases,
that is, as 14 to 16. In equal times it is not equal volumes but equal
weights of these two gases that are transpired, the more heavy gas
being more slowly transpired in proportion to its greater density.
Mixtures of oxygen and nitrogen have the mean velocity of these
two gases, and hence the time of air is also found to be proportional
to its density when compared with the time of oxygen.

The relation between nitrogen and oxygen is equally precise as
that between nitrogen and hydrogen. The densities calculated from
the atomic weights of oxygen and nitrogen, namely, 16 and 14,
being 1 for oxygen, 0"9010 for air and 0*8750 for nitrogen, the ob-
served times of' transpiration of equal volumes of the same gases are
for oxygen 1, air 0-8970 to 0*9010, and for nitrogen to 0*8708. The
result for carbonic acid, which is perhaps next in interest, appears '
^t first anomalous. It is, that the transpiration time of this gas is
inversely proportional to its density : when compared with oxygen or
0*7272, the time of oxygen being 1, their velocities will of course be
directly as their densities. It is to be remembered, however, that
carbonic acid is a compound gas, containing an equal volume of
oxygen. The second constituent, carbon, which increases the weight
of the gas, appears to give additional velocity to the oxygen in the
same manner and to the same extent as inc» eased density from pres-
sure or from cold increases the transpiration velocity of pure oxygen
itself. A result of this kind shows at once the important chemical
bearing of gaseous transpirability, and claims for it a place with the
doctrines of gaseous densities and combining volumes. The circum-
stance that the transpiration time of hydrogen is one-half of that of
nitrogen, indicates that the relations of transpirability are even more
simple in their expression than the relations of density among gases.
In support of the same assertion may be adduced the additional fact,
that binoxide of nitrogen, although differing in density, has the same
transpiration time as nitrogen. Protoxide of nitrogen and carbonic
acid have one transpiration time; so have nitrogen and carbonic
oxide, as each pair has a common density.

The transpiration of twenty other gases and vapours is experi-
mentally determined, and shown to be uniform, like the preceding

Royal Society. S^S

gases, with tube resistances varying in amount from 1 to 1000. Tliis
list includes protocarburetted liydrogen, olefiant gas, ammonia, cya-
nogen, hydrocyanic acid, hydrosulphuric acid, bisulphide of carbon,
sulphurous acid, sulphuric acid, chlorine, bromine, hydrochloric acid,
ether, methylic ether, chloride of methyl, coal-gas and the vapours of
water, alcohol and coal-tar naphtha.

The principal results respecting the transpiration of these vapours,
and on the influence which pressure and temperature have upon the
transpiration of a gas, are summed up as follows : —

The velocity of protocarburetted hydrogen is 0'8, that of hydrogen
being I.

The velocity of chlorine -appears to be 1 ^ that of oxygen ; of bro-
mine vapour and sulphuric acid vapour the same as that of oxygen.

Ether vapour appears to have the same velocity as hydrogen gas ;
their densities are as 37 to 1.

Olefiant gas, ammonia and cyanogen appear to have equal or nearly
equal velocities, which approach closely to double the velocity of
oxygen.

Hydrosulphuric acid gas and bisulphide of carbon vapour appear
to have equal or nearly equal velocities.

The compounds of methyl appear to have a less velocity than the
corresponding compounds of ethyl, but to be connected by a certain
constant relation.

The resistance of a capillary tube of uniform bore to the passage
of any gas is directly proportional to the length of the tube.

The velocity of passage of equal volumes of air of the same tem-
perature, but of different densities of elasticities, is directly propor-
tional to the density. The denser the air, the more rapidly does it
pass under a constant propulsive pressure.

Rarefaction by heat has a similar and precisely equal effect in
diminishing the velocity of the transpiration of equal volumes of air,
as the loss of density and elasticity by diminished pressure has.

A greater resistance in the capillary is required to bring out the
law of densities, than appears necessary for the two preceding results ;
and a resistance still further increased, and the highest of all, to
bring out the law of temperatures.

Finally, transpiration is generally promoted by density, and equally
whether the increased density is due to compression, to cold, or to
the addition of an element in combination, as the velocity of oxygen
is increased, by combining it with carbon without change of volume,
in carbonic acid gas.

It did not enter into the plan of the author to investigate the pass-
age of gases through tubes of great diameter, and to solve pneuma-
tic problems of actual occurrence, such as those offered in the dis-
tribution of coal-gas by pipes. But he states that the results must
be similar, with truly elastic gases such as air and carburetted hy*
drogen, whether the tubes are capillary or several inches in diameter,
provided the length of the tube is not less than 4000 times its dia-
meter, as in the long glass capillaries of his experiments. The small
propulsive pressure applied to- coal-gas is also favourable to transpi-

544 lioyal Society.

ration, as well as the great length of the mains ; and he therefore
Avould expect the distribution of coal-gas in cities to exemplify ap-
proximately the laws of gaseous transpiration. The velocity of coal-
gas should be \'515, that of air being 1, under the same pressure.
And with a constant propulsive pressure in the gasometer, the flow
of gas should increase in volume with a rise of the barometer or with
a fall in temperature, directly in proportion to the increase of its
density from either of these causes.

These laws, it will be observed, are entirely different from those
which direct the passage of gases through an aperture in a thin plate,
or their flow into a vacuum as it is usually said, and could not be
deduced, like the latter, from our speculative ideas respecting the
elastic fluids.

" On the Automatic Registration of Magnetometers and Me-
teorological Instruments by Photography." — No. III. By Charles
Brooke, M.B., F.R.S.

The author describes the construction of an apparatus for regis-
tering the variation of the thermometer and psychrometer on one
sheet of paper. As in the apparatus for registering the vertical force
magnetometer, described in a former paper, the photographic paper
is placed between two concentric cylinders, placed with the axis ver-
tical, and carried round on a revolving plate or turn-table by the
hour-hand of a time-piece, which makes half a revolution in twenty-
four hours ; thus each half of the paper presents a record of the
variation of one instrument during twenty-four hours. The scales
of the instruments are continuously impressed on the paper by placing
fine wires opposite each degree across the aperture through which
the light falls on the stem ; the light transmitted by the empty bore
is intercepted by these wires, and the darkened portion of the paper
is marked by a series of parallel pale lines corresponding to each
degree : thus the distortion of the scale arising from the varying di-
rection of the pencils of light is corrected. Every tenth degree is
marked by a coarser wire, and therefore a broader line, as also the
points 32°, 54<°, 76°, 98° ; one at least of these points will occur on
each register, and the position of the extra broad line serves to iden-
tify the part of the scale to which the register relates.

An alteration in the mode of adjusting the wick of the camphine
lamps described in a former paper is mentioned, by which the chance
of smoking is considerably diminished ; likewise the successful ap-
plication of naphthalised gas, and of an oil-lamp, to photographic
registration.

The paper concludes with the description of a new method of de-
termining the scale and temperature coeflScients of the force magne-
tometers, by which a greater degree of accuracy is presumed to be
attained than by the methods ordinarily employed. Two magnets
designed for self-registering instruments for the observatories at
Cambridge and Toronto, having been submitted to this method, gave
consistent results which indicate the law of the temperature coefficient
to be sensibly different from that which has hitherto been assumed.

[ 545 ]
LXV. Intelligence and Miscellaneous Articles.

ON THE PASSAGE OF HYDROGEN GAS THROUGH SOLID BODIES.
BY M. LOUYET.

M. LOUYET has made a curious observation connected with the
history of hydrogen : he found that when a horizontal current of this
gas, emitted from a capillary orifice, was directed upon a sheet of
])aper held vertically and perpendicularly to the gaseous current, the
fluid passes through the jjaper without being sifted, as might be ex-
pected, but retaining the form of a current, and so perfectly that it
may be inflamed behind the paper, absolutely as if it did not exist.
Spongy platina placed behind the paper became incandescent, and it
is to be observed that the pressure under which this phsenomenon
is produced does not exceed that of 40 to 48 inches of water.

M. Louyet has also stated that hydrogen gas passes in the same
manner through gold, silver and tin leaf, even double, and also
through thin membranes of gutta percha, such as are obtained by
evaporating a solution of this substance in chloroform.

Lastly, the author has observed that the same gas does not sen-
sibly pass through pellicles of glass obtained by strongly blowing a
bulb at the end of a tube, however thin they may be. — Ann. de Ch.
et de Phys., Septembre 1849.

QUALITATIVE AND QUANTITATIVE DETERMINATION OF PHOS-
PHORIC ACID. BY M. LECONTE.

The importance of phosphoric acid in vegetable and animal physi-
ology is well known, and, in this point of view, the utility of detecting
the presence and determining the quantity of this acid in food, ma-
nures, &c., has been duly appreciated, particularly in those manures
intended to fertilize the soils in which wheat is grown.

For twelve months several chemists have been occupied with this
question, which appears a proof both of the interest and difficulty at-
tached to solving it. M. Raewsky's process by acetate of peroxide of
iron, and that of M. Cotterau by nitrate of silver, have been described.
M. Leconte states that he has found the soluble salts of uranium to
be the most certain for detecting and determining the quantity of
phosphoric acid, on account of the absolute insolubility of the phos-
phate of uranium, and the facility with which this salt precipitates
notwithstanding the presence of other saline substances, acids, &c.

The quantitative determination of phosphoric acid in soluble phos-
phates is very simple. A solution of nitrate of uranium is prepared,
of which every cubic centimetre precipitates Ogr.'OOI of phosphoric
acid ; a known weight of the phosphate to be analysed is taken and
dissolved in a known bulk of distilled water, taking care to neutral-
ize it ; fifty cubic centimetres of this liquor are boiled in a flask, and,
by the aid of a graduated tube, nitrate of uranium is added to it, till
the liquor standing over the precipitate becomes limpid. It must be
boiled for a second after each addition of the test solution. — Journ. de
Ch. Med., Novembre 1849.

Phil. Mag. S. 3. No. 239. Suppl. Vol. 35. 2 N

5^6

INDEX TO VOL. XXXV.

Acids : — carbo-benzoic,73; molyb-
dic, 75 ; alizaric, 212 ; pyro-aliza-
ric, 215; rubiacic, 216; sulphani-
lic, 237 ; stearic, ib. ; melissic, 247 ;
palmitic, 250.

Airy (Prof.) on instruments adapted
to the measure of small meridional
zenith distances, 294 ; on an in-
strument for performing arithmeti-
cal divisions and multiplications,
521.

Albite, analysis of, 484.

Algebra, on a new system of imagi-
naries in, 133; on quadruple, and
equations of the fifth degree, 434,

Alizaric acid and salts, 212.

Alizarine, on the properties and com-
position of, 210.

Alkaloids, on the nitrogenous princi-
ples of vegetables as the sources of,
534.

Altain (M.) on gold in certain mines
of the department of the Rhone,
309.

Ammonia, on the quantity of, in at-
mospheric air, 318.

Anharmonic ratio, observations on,
165.

Animals, on the inorganic constitu-
ents of, 9 ; on the structure of the
dental tissues of marsupial, 540.

Arkansite and Brookite, identity of.

Arsenic, on the state in which it exists
in the deposit from mineral waters,
465.

Ashes of organic substances, on the
analysis of, 1, 15, 309.

Asturias, on the geological structure
of the, 34.

Atmosphere, on the amount of am-
monia contained in the, 318.

Attraction, on the universal law of,
234.

Aurora borealis, of Nov. 17, 1848,
account of the, 69; of Feb. 22,
1849, observations on the, 71.

Aurorae boreales, on the cause of, 446.

Balsam of Peru, experiments on, 72.

Barreswil (M.) on the chemical na-
ture of the egg, 158.

Bartenbach (M.) on gold in certain
mines of the department of the
Rhone, 309.

Becquerel (M.) on the development
of electricity in the act of muscular
contraction, 53.

Beechey (Capt. F. W.) on the tides
of the English Channel, 149.

Beke (C. T.) on the sources of the
Nile, 99.

Bell's (W.) instrument for perform-
ing arithmetical multiplications and
divisions, description of, 521.

Beswick (S.) on a method for com-
puting magnetic declination, 511.

Bile, on the inorganic constituents of
the, 278.

Birt (W. R.) on the production of
lightning by rain, 16 1.

Blondeau (M. C.) on the natural
sources and new mode of preparing
sulphuric acid, 467.

Blood of the ox, analysis of the ash
of the, 185.

Bodies, on the inorganic constituents
of organic, 1, I7l, 27l ; on some
facts relative to the spheroidal state
of, 60 ; on the vibratory movements
of magnetic and non-magnetic, 422.

Boltonite, analysis of, and observa-
tions on, 462.

Bond (Prof.) on the appearance of
Saturn's ring, &c. in* the equato-
real of Cambridge, United States,
519.

Bonjean (M.) on glairine, 75 ; on
glairidine, 78 ; on zoi'odine, ib.

Bontemps (G.) on some modifications
in the colouring of glass by metallic
oxides, 439.

Books, new : — ^Thompson's Introduc-
tion to Meteorology, 225 ; Gal-
braith's Edition of Ainslie's Trea-
tise on Land-Surveying, 293.

Boracic acid, influence of, upon vitri-
fication, 479.

Boutigny (P. H) on some facts rela-

INDEX.

547

tive to the spheroidal state of bo-
dies, 60.

Brodie (B. C.) on the chemical nature
of wax, 244.

Bromine, on the detection of, 156 ;
on a method of ascertaining the
quantity of, 394.

Bronwin (Rev. B.) on the theory of
the tides, 187, 264, 338.

Brooke (C.) on the automatic regis-
tration of magnetometers and me-
teorological instruments by photo-
graphy, 544.

Brookite and Arkansite, identity of,
75.^

Bryce' (Jas.) on the lignites and al-
tered dolomites of the island of
Bute, 81.

Bucholzite, on the identity of, with
kyanite, 459.

Buff (Prof.) on Du Bois Reymond's
discovery of the development of
electricity by muscular contraction,
288.

Bull (B. W.) on the inorganic con-
stituents of yeast, 286.

Caillat (M.) on the analysis of plants
by incineration, 309-

California gold region, notes on the,
470.

Cambridge Philosophical Society, pro-
ceedings of the, 228, 392.

Carbanilamide, on the properties and
composition of, 236.

Carolles (M. Blondeau de) on the for-
mation of fatty matters in vege-
tables, 158.

Challis (Rev. J.) on the views of the
Astronomer Royal respecting the
modification of sounds by distance
of propagation, 241.

Chancel (G.) on the nitrogenous com-
pounds of the benzoic series, 236.

Chapman (E. J.) on the notation of
crystals, 321.

Chlor-melal, on the properties and
composition of, 249.

Chloroform, on the refractive and di-
spersive power of, 94 ; observations
on, 314.

Claudet (M.) on the theory of the
principal phaenomena of photogra-
phy in the Daguerreotype process,
374.

Claus (M. C.) on the metals of pla-
tina, 396.

2

Cobalt, on the preparation of pure
oxide of, 154; on alumiuate of, 155.

Cockle (J.) on systems of algebra
involving more than one imaginary,
and on equations of the fifth de-
gree, 434.

Colophene, on the preparation and
composition of, 477.

Colouring principles of madder, on
the, 204.

Copper, on the blue arseniate of,
310.

Corenwinder (M. B.) on the prepara-
tion of nitrogen gas, 317.

Corundellite, analysis of, 452.

Cotton, on a peculiar fibre of, 334.

Crum (W.) on a peculiar fibre of cot-
ton which is incapable of being
dyed, 334.

Crystals, on the notation of, 321.

Cumberland, on the meteorology of
the Lake districts of, 70.

Curves, on the intrinsic equation of,
229.

Daguerreotype process, observations
on the, 374.

Davies (T. S.) on geometry and geo-
meters, 497.

Davy (Dr. J. D.) on carbonate of lime
as an ingredient of sea-water, 232.

De la Rive (Prof.) on the vibratory
movements which magnetic and
non-magnetic bodies experience
under the influence of external and
transmitted electric currents, 422 ;
on the cause of aurorae boreales,
446.

De Morgan (Prof.) on anharmonic
ratio, 165.

Desains (P.) on the rotation of the
plane of polarization of heat by
magnetism, 481.

Despretz (M. C.) on the electricity
developed by muscular contraction,
55.

Deville (M. H.)on the combinations
of oil of turpentine and water, 474;
on the action of phosphoric acid on
the hydrates of oil of turpentine,
477.

Dixon (T. H.) on rain, the cause of
lightning, 392.

Doepping (M.) on a compound of
sulphurous acid and water, 393.

Dolomites of the island of Bute, on
the, 81.
N2

548

INDEX.

Drach (Mr. S. M.) on Epicyclical
curves, 487.

Dyeing, observations on the process
of, 221.

Earnshaw (Rev. S.) on the transfor-
mation of linear partial differential
equations, 24.

Earth, on an experiment to determine
the density of the, 95 ; on the va-
riation of gravity at the surface of
the, 228.

Egg, on the chemical nature of the,
158 ; on the inorganic constitu-
ents of the white and yolk of the,
286.

Elastic solids, on an instrument for
measuring the extensibility of, 92.

Electric current, on the sounds pro-
duced by the, 422.

Electricity, development of, in the act
of muscular contraction, 53, 55 ;
of steam, observations on, 490.

Emerylite, analysis of, 451.

Enamel, on the structure of the,
540.

Epicyclical curves, on an easy rule
for formularizing, 487.

Equations, on the transformation of
linear partial differential, 24 ; gene-
ral methods in analysis for the re-
solution of linear, 147.

Ethylamine, on the properties and
composition of, 312.

Euphyllite, analysis of, 454.

Falling stars, remarks on, 524.

Fehling (M.) on the methods of as-
certaining the quantity of bromine
in solution in mother-v^^aters, 394.

Fibrolite, on the identity of, with ky-
anite, 459.

Fish, on the microscopic structure of
the scales and dermal teeth of some,
531.

Fleitmann (M.) on the ashes of hu-
man fsBces and urine, 273.

Forbes (Prof J. D.) on an instrument
for measuring the extensibility of
elastic solids, 92 ; on the refractive
and dispersive power of chloroform,
94 ; on the determination of the
earth's density, 95 ; on the alleged
evidence for a physical connexion
between stars forming binary or
multiple groups, arising from their
proximity alone, 132.

Fresenius (Dr. C. R.) on the proper

balance of the food in nutrition,
127 ; on the quantity of ammonia
contained in atmospheric air, 318.^

Gases, on the motion of, 541 .

Geology, researches in physical, 66.

Geometry and geometers, 497.

Gerhardt (M.) oti the composition of
stearic acid, 237.

Gladstone (Dr. J. H.) on the com-
pounds of the. halogens with phos-
phorus, 345.

Glairidine, observations on, 78.

Glairine, observations on, 75.

Glaisher (J.) on the weather during
the quarters ending June 30 and
September 30, 1849, 137, 356 ; on
the reduction of the therraometrical
observations made at the apart-
ments of the Royal Society from
the year 1744-1781, and 1787-
1843, 151.

Glass, on some modifications in the
colouring of, by metallic oxides,
439.

Gold in certain mines of the depart-
ment of the Rhone, occurrence of,
309.

Gold region of California, notes on,
470.

Graham (T.") on the motion of gases,
541.

Gravity, on the variation of, at the
surface of the earth, 228.

Grove (W. R.) on the effect of sur-
rounding media on voltaic ignition,
114; on the direct production of
heat by magnetism, 153.

Hamilton (Sir W. R.) on quaternions,
or on a new system of imaginaries
in algebra, 133, 200.

Hargreave (C.J. ), researches concern-
ing numbers, 36 ; on general me-
thods in analysis, for the resolution
of linear equations, infinite differ-
ences, and linear differential equa-
tions, 147.

Heat generated in a platinum wire by
a voltaic current, observations on,
114 ; on the direct production of,
by magnetism, 153 ; on the rota-
tion of the plane of polarization of,
by magnetism, 481 ; on the mecha-
nical equivalent of, 533.

Hennessy (H.) on physical geology,
66.

Herschel (Sir J. F. W.) on the deter-

INDEX.

549

mination of the most probable orbit
of a binary star, 386.

Honey, on the composition of, 398.

Horse-flesh, on the inorganic consti-
tuents of, 271.

Huxley (H.) on the anatomy and
affinities of the family of Medusae,
528.

Hydrogen gas, on the passage of,
through solid bodies, 545.

Hylseosaurus, on the osteology of the,
64.

Iguanodon, osteology of the, 64.

Indianite, analysis of, 486.

Institution of Civil Engineers, pro-
ceedings of the, 526.

Iodine, on the detection of, 156, 395.

Iridium, on some compounds of, 396.

Jones (H. B,) on the variations of the
acidity of the urine in the state of
health, and on the influence of me-
dicines on the acidity of the urine,
162.

Joule (J. P.) on the mechanical equi-
valent of heat, 533.

Kopp (M.) on liquid storax and bal-
sam of Peru, 72.

Kyanite, on the identity of Silliman-
ite, fibrolite, and Bucholzite with,
459.

Lassaigne (M. J. L.) on the state in
which arsenic exists in the deposit
from mineral v/aters, 465.

Laurent (M.) on the composition of
stearic acid, 237.

Leconte (M.) on the qualitative and
quantitative determination of phos-
phoric acid, 545.

Lightning, on the production of, by
rain, 161, 392.

Lignites and dolomites of the island
of Bute, on the, 81.

Louyet (M.) on the preparation of
pure oxide of cobalt, 154 ; on alu-
minate of cobalt, 155 ; on the pass-
age of hydrogen gas through solid
bodies, 545.

Lowe (E. J.) on a remarkable solar
phaenomenon, 437 ; on falling stars,
524.

Lubbock (Sir J. W.) on shooting
stars, 356.

Lyman (Rev. C. S.) on the California
gold region, 470.

Madder, on the colouring principles
of, 201.

Maes (M.) on the influence of boracic
acid upon vitrification, 479.

Magnetic declination, illustrations of
a method for computing, 511.

Magnetism, on the direct production
of heat by, 153; on the rotation
of the plane of polarization of heat
by, 48] ; on a mathematical theory
of, 540.

Magnetometers, on the automatic re-
gistration of, by photography, 544.

Man and mammalia, on the develop-
ment and varieties of the great an-
terior veins in, 537-

Mantell (G. A.) on the osteology of
the Iguanodon and Hylaeosaurus,
64.

Marshall (John) on the development
and varieties of the great anterior
veins in man and mammalia, 537.

Matteucci (M.) on the voltaic arc,
289.

Medusae, on the anatomy and aflini-
ties of the family of, 528.

Melene, on the preparation and pro-
perties of, 253.

Melissic acid, on the properties and
composition of, 247.

Melissine, on the preparation and
composition of, 246.

Metallic oxides, on the colouring of
glass by, 439.

Meteorological instruments, on the
automatic registration of,by photo-
graphy, 544.

Meteorological observations, 79, 159,
239, 319, 399, 479.

Meteorology of the Lake district of
Cumberland, on the, 70.

Meteors, 479.

Methylamine, on the properties and
composition of, 311.

Mialhe (M.) on chloroform, 314.

Milk, on the inorganic constituents of,
279.

Miller (J. F.) on the meteorology of
the Lake district of Cumberland and
Westmoreland, 70.

Miller (Prof.) on the identity of
Brookite and Arkansite, 75.

Mineralogy : — Arkansite, 75 ; Brook-
ite, ib. ; Emerylite, 451 ; Corundel-
lite, 452 ; Euphyllite, 454 ; Union-
ite, 457 ; Monrolite, 458 ; Silli-
manite,459; fibrolite, 460; Buchol-
zite, ib. ; kyanite, ib. ; Boltonite,

5S0

INDEX.

462 ; Nuttallite, 464 ; granular
albite, 484 ; Indianite, 486.

Mineral waters, on the state in which
arsenic exists in the deposit from,
465.

Mirrors, remarks on the process of
grinding large, 523.

Molybdic acid, on the estimation of,
75.

Monrolite, analysis of, 458.

Myricine, investigations on, 244.

Nepenthes, on the chemical composi-
tion of the fluid in the ascidia of,
192.

Newton's Principia, on Hegel's criti-
cism of, 392.

Nile, on the sources of the, 99.

Nitrobenzamide, on the action of the
hydrosulphate of ammonia upon,
236.

Nitrogen gas, on the preparation of,
317.

Noctiluca miliaris, observations and
experiments on, 401.

Numbers, analytical researches con-
cerning, 36.

Nutrition, on the proper balance of
food in, 127.

Nuttallite, analysis of, and observa-
tions on, 464.

Oil of turpentine and water, on the
combinations of, 474 ; on the action
of phosphoric acid on the hydrates
of, 477.

Osmium, on some compounds of, 397.

Palmitic acid from the saponification
of myricine, observations on the,
250.

Paton (J.) on the Old Southend Pier-
head, and on the nature and ravages
of the Teredo navalis,and the means
adopted for preventing its attacks,
526.

Peas and pea-straw, examination of
the inorganic constituents of, 171.

Phillips (Reuben) on electricity and
steam, 490.

Phosphorescence, vital, on the phse-
nomena of, 401.

Phosphoric acid, on the qualitative
and quantitative determination of,
545.

Phosphorus, on the compounds of the
halogens with, 345.

Photography, on the theory of the
principal phaenomena of, 374.

Plants, on the inorganic constituents
of, 1 ; on the amount of silica con-
tained in some, 181 ; on the ana-
lysis of, by incineration, 309.

Platina, contributions to the chemistry
of the metals of, 396.

Poleck (M.) on the inorganic consti-
tuents of the white and yolk of
hen's eggs, 281.

Precipitates, on a simple apparatus for
washing, 96.

Pring (Dr. J. H.) on the Noctiluca
miliaris, the animalcular source of
the phosphorescence of the British
seas, 401.

Pringle (W.) on an easy mode of mea-
suring solar objects, 467.

Provostaye (M. F. de la) on the rota-
tion of the plane of polarization of
heat by magnetism, 48 1 .

Pyro-alizaric acid, on the preparation
and composition of, 215.

Quaternions, a new system of imagi-
naries in algebra, 133, 200.

Railway bridges, on a differential
equation relating to the breaking
of, 230.

Rain, on the production of lightning
by, 161, 392.

Rape-seed and rape-straw, examina-
tion of the inorganic constituents
of, 177.

Reboulleau (M.) on blue arseniate of
copper, 310.

Reflex zenith telescope, description of
the, 294.

Reynoso (M. A.) on the detection of
iodine and bromine, 156.

Rose (M. H.) on the estimation of
molybdic acid, 75 ; on the inorganic
constituents of organic bodies, 1,
171, 271.

Rosse (Lord) on the process of grind-
ing large mirrors, 523.

Roval Astronomical Society, proceed-
ings of the, 294, 386, 519.

Roval Society, proceedings of the, 64,
147, 231,528.

Rubiacic acid and salts, on the prepa-
ration and composition of, 216.

Rubiacine, on the properties and com-
position of, 215.

Rubian, on the properties and compo-
sition of, 218.

Ruthenium, on some compounds of,
397.

INDEX.

551

Saturn's ring, appearance of, in the
equatoreal of Cambridge, United
States, 519.

Schunck (E.) on the colouring matters
of madder, 204.

Sea-water, on carbonate of lime as an
ingredient of, 232, 308.

Shooting stars, observations on, 356.

Silliman (Dr. B., jun.) on several
American minerals, 451 ; on a
granular albite associated with co-
rundum, and on the Indianite of
Bournon, 484.

Sillimanite, fibrolite and Bucholzite,
on the identity of, with kyanite,
459.

Slatter (J.) on the aurora borealis of
Feb. 22, 1849, 71.

Smythies (J. K.) on the universal law
of attraction, 234.

Solar objects, easy mode of measuring,

467.

Solar phsenomenon, account of a re-
markable, 437.

Soubeiran (M.) on chloroform, 314 ;
on the composition of honey,
398.

Sounds, on the views of the Astrono-
mer Royal respecting the modifica-
tion of, 241.

Star, binary, on the determination
of the most probable orbit of a,
386.

Stars forming binary or multiple
groups, on the alleged evidence for a
physical connexion between, 132.

Steam, on the electricity of, 490.

Stearic acid, on the composition of,
237.

Stenhouse (J.) on the nitrogenous
principles of vegetables as the
sources of artificial alkaloids, 534.

Stokes (G. G.) on the variation of
gravity at the surface of the earth,
228 ; on a differential equation re-
lating to the breaking of railway
bridges, 230.

Storax, liquid, experiments on, 72.

Struve (M.) on the amount of silica
contained in some plants, 181.

Styracine, observations on, 74.

Styrol, experiments on, 73.

Sulphuric acid, natural sources and
new mode of preparing, 467.

Sulphurous acid, on the hydrates of,
393.

Summers (E, C.) on a simple appa-
ratus for washing precipitates, 96.

Teeth, on the microscopical structure
of, 531, 540.

Terebene, on the preparation and pro-
perties of, 477.

Teredo navalis, on the nature and
ravages of the, 526.

Thermometrical observations made at
the apartments of the Royal So-
ciety, on the reduction of the, 151.

Thompson's (D. P.) Introduction to
Meteorology, reviewed, 225.

Thomson (W.) on a mathematical
theory of magnetism, 540.

Thorel (M. L.) on the detection of
small quantities of iodine, 395.

Tides, on the theory of the, 149, 187,
264, 338.

Tomes (J.) on the structure of the
dental tissues of marsupial animals,
and more especially of the enamel,
540.

Unionite, analysis of, 457.

Urine, on the variations of the acidity
of the, and on the influence of me-
dicines on the acidity of the, 152 ;
analysis of the ashes of, 273.

Valeramine, on the preparation and
composition of, 313.

Vegetables, on the formation of fatty
matters in, 158 ; on the nitroge-
nous principles of, as the sources of
artificial alkaloids, 534.

Verneuil (M. E. de) on the geological
structure of the Asturias, 34.

Villarceau (M. Yvon) on the deter-
mination of the most probable orbit
of a binary star, 388.

Vitrification, on the influence of bo-
racic acid upon, 478.

Vcelcker (Dr. A.) on the chemical
composition of the fluid in the
ascidia of Nepenthes, 192.

Voltaic arc, observations on the, 289.

ignition, on the effect of sur-
rounding media on, 114.

Watkins (Rev. C. F.) on the aurora
borealis of the I7th of November,
1848, 69.

Wax, investigation of the chemical
nature of, 244.

Weather, remarks on the, 137, 357.

Weber (M.) on the inorganic consti-
tuents of peas and pea-straw, 171 ;
of rape-seed and rape-straw, 177;

552

INDEX.

of wheat and wheat-straw, 182 ; of
the blood of the ox, 185 ; of horse-
flesh, 271 ; of cow's milk, 279-

Weidenbusch (M.) on the inorganic
constituents of the bile (of oxen),
278.

Wheat and wheat-straw, examination
of the ash of, 182.

Whewell (Dr.) on the intrinsic equa-
tion of curves, 229 ; on Hegel's cri-
ticism of Newton's Principia, 392.

White (W.) on carbonate of lime as
an ingredient of sea- water, 308.

Williams (Rev. D.) on a cliff section
of Lundy Island, 28.

Williamson (W. C.) on the micro-
scopic structure of the scales and
dermal teeth of some ganoid and
placoid fish, 531.

Wurtz (M. A.) on methylamine and
ethylamine, 311 ; on valeramine or
valeric ammonia, 313.

Xanthine, on the preparation and
composition of, 219.

Yeast, on the inorganic constituents
of, 286.

Zenith distances, on instruments
adapted for measuring, 294.

Zo'iodine, observations on, 78.

END OF THE THIRTY-FIFTH VOLUME.

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