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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.
ROBERT KANE, M.D. M.R.I.A.

" Nee aranearum sane textus ideo melior quia ex se fila gignunt, ncc noster
vilior quia ex alienis libamus ut apes." Just. Lips. Polit. lib. i. cap. 1. Not.

VOL. XXIV.

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

JANUARY— JUNE, 1S44.

LONDON:

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

SOLD RY LONGMAN, BROWN, GREEN, AND LONGMANS ; CABELL; SIMPKIN,
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CHARLES BLACK, AND THOMAS CLARK, EDINBURGH; SMITH

AND SON, GLASGOW ; HODGES AND SMITH, DUBLIN:

AND G. W. M. REYNOLDS, PARIS.

The Conductors of the Philosophical Magazine have to acknowledge the editorial
assistance rendered them by Mr. Eiiward W. Brayi.ey, F. L. S. F.G.S., &c.
Librarian to the London Institution-

CONTENTS OF VOL. XXIV.

(THIRD SERIES.)

NUMBER CLVI.— JANUARY, 1844.

Page
Dr. D. P. Gardner on the Action of Yellow Light in producing

the Green Colour, and Indigo Light the Movements of Plants 1
Prof. De Morgan on the Reduction of a Continued Fraction to

a Series 15

Messrs. R. Warington and W. Francis on the Action of Alkalies

on Wax 17

Dr. G. Fownes on the Action of Oil of Vitriol upon Ferrocya-

nide of Potassium 21

Mr. S. Tebay's Demonstration of the Rule of Descartes 24

J. J.'s Observations on the Notations employed in the Differen-
tial and Integral Calculus 25

Note on the Experiments of Moser. (Extract from the Gior-

nale Toscano di Scienze Mediche, Fisiche, &c.) 38

Mr. J. Denham Smith's Note on the Paper published in the
Philosophical Magazine for September 1843, " On the Com-
position of an Acid Oxide of Iron (Ferric Acid) " 41

Dr. Martin Barry's Remarks on a Work by Prof. Bischoff of
Heidelberg, entitled " Entwickelungsgeschichte des Kanin-
chen-Eics " (History of the Development of the Ovum of the

Rabbit), 1842 42

Mr. G. Salmon on the Properties of Surfaces of the Second
Degree which correspond to the Theorems of Pascal and

Brianchon on Conic Sections 49

Proceedings of the Geological Society 51

London Institution 76

Preparation of Hyposulphite of Soda, by M. Walchner 78

On the Action of Chlorides upon Protochloride of Mercury, by

M. Mialhe 78

Meteorological Observations for November 1843 .... 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 Sand wick Manse, Orkney 80

NUMBER CLVIL— FEBRUARY.

Mr. II. Moon on the Undulatory Theory of Interference .... 81
The Rev. Brice Bronwin's Differential Equations of the Moon's

Motion 85

a'2

IV CONTENTS OF VOL. XXIV. — THIRD SERIES.

l'age
Mr. Herbert Spencer's Remarks upon the Theory of Reciprocal
Dependence in the Animal and Vegetable Creations, as regards

its bearing upon Palaeontology 90

The Rev. J. Challis on a particular case of the Application of

Criteria of Integrability

Mr. R. Hunt on the Influence of Light on Plants . 96

Dr. Kane's Abstract of a Memoir on the Chemical Constitution
of the Plants of Flax and Hemp, considered with relation to

the conditions of their Growth and Preparation 98

Mr. A. Connell's Chemical Examination of the Tagua Nut, or

Vegetable Ivory • 104

Mr. J. P. Joule on the Intermittent Character of the Voltaic
Current in certain cases of Electrolysis ; and on the Intensi-
ties of various Voltaic Arrangements 106

Dr. A. W. Hofman's Chemical Investigation of the Organic

Bases contained in Coal- Gas Naphtha 115

Dr. Stenhouse on the Products of the Distillation of Meconic

Acid ; 1^8

Dr. Faraday's speculation touching Electric Conduction and the

. Nature of Matter I36

Proceedings of the Geological Society 144

Detonation of the Alloy of Potassium and Antimony 153

On the Chemical Constitution of Wolfram, by M. Marguerite. 153
Analysis of Ancient and Fossil Bones, by MM. Girardin and

Preisser 154

On Apiin, by Mons. H. Braconnot 155

On Sulphocamphoric Acid, by M. Philippe Walter 157

Meteorological Observations for December 1843 159

Table 160

NUMBER CLVIII.— MARCH.

Mr. A. Connell's Further Observations on the Voltaic Decom-
position of Solutions 161

Mr. E. W. Binney on the remarkable Fossil Trees lately disco-
vered near St. Helen's 165

Mr. J. Goodman on the Cause of Dissimilarity in the Pheno-
mena of the Ordinary and Voltaic Electric Fluids 174

Mr. W. J. Henwood on the (Displacements) Heaves of Metal-
liferous Veins by Cross-veins. (Part I.) 180

Mr. W. Galbraith on the Determination of the Distance of a
given point on the Earth's Surface at, or very near, the level
of the sea, by observations on its depression from a known
height above it 181

CONTENTS OF VOL. XXIV. THIRD SERIES. V

Page
Dr. W. Gregory's Further Contributions to the Chemical Hi-
story of the Products of the Decomposition of Uric Acid . . 186
Mr. W. H. Balmain's Additional Observations on iEthogen . . 191
Mr. S. M. Drach on the Empirical Law in the Enumeration of

Prime Numbers 192

Dr. A. W. Hofman's Chemical Investigation of the Organic

Bases contained in Coal-Gas Naphtha (continued) 193

Proceedings of the Royal Society 206

■ Geological Society • . 217

An Experiment in proof of the Latent Light in Mercury, by

Professor Moser 232

On the Equivalent of Zinc, by Mons. P. A. Favre 233

Mode of distinguishing Zinc from Manganese when dissolved

in Ammoniacal Salts, by M. Otto 234

Preparation of Protiodide of Iron, by M. Mialhe 234

On Chlorazotic Acid, by M. Baudrimont 235

Analysis of Beaumontite, by Mons. A. Delesse 236

Description and Analysis of Sismondine, by M. A. Delesse . . 238

A Meteorological Phenomenon 238

Meteorological Observations for January 1844 239

Table 240

NUMBER CLIX.— APRIL.

Mr. W. Cram on the Manner in which Cotton unites with Co-
louring Matter 241

The Rev. A. Sedgwick's Outline of the Geological Structure
of North Wales 246

Mr. W. J. Henwood on the Heaves of Metalliferous Veins by
Cross-veins. — Part II 258

Dr. A. W. Hofman's Chemical Investigation of the Organic
Bases contained in Coal-Gas Naphtha (concluded) 261

Prof. Grove on the Gas Voltaic Battery. — Experiments made
with a view of ascertaining the rationale of its action and
its application to Eudiometry 268

Prof. Latham's Facts and Observations relative to the Science
of Phonetics 279

Prof. T. Bischoff's Reply to Dr. Martin Barry's " Remarks" on
his " Entwickelungsgeschichte des Kaninchen-Eies 281

Mr. Sylvester's Elementary Researches in the Analysis of Com-
binatorial Aggregation 285

Notices respecting New Books : — Prof. D. Low's Inquiry into
the Nature of the Simple Bodies of Chemistry ; A Memoir
of the Life, Writings and Mechanical Inventions of Edmund
Cartwright, D.D., F.R.S 296

VI CONTENTS OF VOL. XXIV. — TH1KD SERIES.

Page

Proceedings of the Royal Astronomical Society 300

Geological Society 308

Experiments on Coffee 313

A new process for preparing Gallic Acid, by Edward N. Kent . 314

Analysis of Melilite, by Mons. A. Damour 314

Description and Analysis of Humboldtilite, and Identity with

Melilite, by Mons. A. Damour 316

Analysis of Guano, by MM. J. Girardin and Bidard 317

Analysis of Pectic Acid, by M. Fromberg 319

Meteorological Observations for February 1844 319

Table.' '. 320

NUMBER CLX.— MAY.

Mr. G. S. Cundell on the practice of the Calotype Process of

Photography 321

The Rev. D. Williams on the Killas Group of Cornwall and
South Devon ; its relations to the subordinate formations in
Central and North Devon and West Somerset ; its natural
subdivisions; and its true position in the scale of British

strata 332

Prof. Grove on the Gas Voltaic Battery. — Experiments made
with a view of ascertaining the rationale of its action and

its application to Eudiometry (continued) 346

Mr. Reuben Phillips's Remarks on the Elasticity of Gases. . . . 354
Mr. T. Taylor on some new Species of Biliary and Intestinal

Concretions 354

Sir D. Brewster on the Law of Visible Position in Single and
Binocular Vision, and on the representation of Solid Figures
by the union of dissimilar Plane Pictures on the Retina. . . . 356
Mr. J. Napier on the Solubility of the Metals in Persulphate

and Perchloride of Iron 365

Mr. W. Herapath's Analyses of the Bath Waters and of the

Bristol Hotwell Water* 371

Mr. J. N. Furze's Observations on Fermentation 372

Proceedings of the Geological Society 375

Zoological Society 378

■ Royal Irish Academy 380

On Absinthic Acid, by C. Zwenger ..." 392

Process for obtaining Osmium, by Mons. E. Fremy 393

Examination of the African Guano, by E. F. Teschemacher . . 394

Ratio of the Drachm and Grain, Avoirdupois 396

Festival in honour of Berzelius 396

Meteorological Observations for March 1844 399

Table 400

CONTENTS OF VOL. XXIV.— THIRD SERIES. VII

NUMBER CLXI.— JUNE.

Page
Prof. Graham's Experiments on the Heat disengaged in Com-
binations 401

Prof. Latham's Facts and Observations relative to the Science

of Phonetics (No. III.) 420

Prof. Grove on the Gas Voltaic Battery. — Experiments made
with a view of ascertaining the rationale of its action and

its application to Eudiometry {concluded) 422

The Rev. J. A. Coombe on the Form of Equilibrium of an In-
extensible String laid on a surface and acted on by any forces 432
Mr. R. Hunt's Chromo-Cyanotype, a new Photographic Process 435
Sir D. Brewster on the Law of Visible Position in Single and
Binocular Vision, and on the representation of Solid Figures
by the union of dissimilar Plane Pictures on the Retina {con-
cluded) 439

Proceedings of the Royal Society 455

National Institute of the United States . . 468

Observations on African Guano, by W. Francis 470

Process for obtaining Iridium, by Mons. E. Fremy 474

An Experiment for rendering apparent the Adjusting Power of

the Eye, by Reuben Phillips 474

Double Carbonate of Ammonia and Magnesia, by M. P. A. Favre 475
On the Identity of Scorodite and Neoctese, by M. Damour . . 476
Comparative analysis of Anatase and Rutile, by M. Damour . . 477

Meteorological Observations for April 1844 479

Table 480

NUMBER CLXIL— SUPPLEMENT TO VOL. XXIV.

Sir J. F. W. Herschel's Observations on the Entrance Passages
in the Pyramids of Gizeh 481

Sir H. T De la Beche's Memorandum on Estuaries and their
Tides 485

The Rev. Brice Bronwin on some Definite Integrals 491

Mr. J. Denham Smith's Note on a paper on Ferric Acid, read
before the Chemical Society May 16, 1843 498

Mr. J. T. Cooper's Observations on Catechuic Acid 500

Mr. A. R. Arrott on a Class of Double Sulphates, containing
Soda and a Magnesian Oxide 502

Mr. R. Warington on a curious Change in the Molecular Struc-
ture of Silver 503

Mr. R. Warington's Note on a Means of Preserving the Crystals
of Salts as permanent objects for Microscopic Investigation . 505

Vllt CONTENTS OF VOL. XXIV. — THIRD SERIES.

Page
Mr. R. Warington's Observations on the Green Teas of Com-
merce 507

Mr. J. Carty's Account of a new Cyanide of Gold 515

Proceedings of the Royal Astronomical Society 516

Academy of Natural Sciences of Philadelphia 541

Energiatype, a New Photographic Process, by Robert Hunt . . 544
Method of Preserving Animal Substances, by M. Gannal .... 545
Index 547

Errata.

Page 164, line 27, for more read none.
19.2, last line, read 191-58=133.
193, line 1, read 173—82=91.

23, for —12 read —2.

... heading of Table,yb>- 1000.r2 read x = 1 000 x.

326, line 2 from bottom, for 200 grains read 400.

327, first Vine, for fifty grains read one hundred.

THE
LONDON, EDINBURGH and DUBLIN

PHILOSOPHICAL MAGAZINE

AND

JOURNAL OF SCIENCE.

[THIRD SERIES.]

JANUARY 1844.

I. On the Action of Yellow Light in producing the Green Colour,
and Indigo Light the Movements of Plants. By D. P.
Gardner, M.D., Corresponding Member of the Lyceum of
Natural History, New York*.

1. rpHE object of this paper is to prove the existence of
■L different properties in the rays of the spectrum, iu
their action on vegetables ; and more especially to show that
the rays which produce the green colour of plants are alto-
gether dissimilar from those which influence their movements
towards light; the colour being developed by the less re-
frangible rays, and chiefly by the yellow; whereas the motion
is influenced by indigo light. The discussion of the subject
will be divided under three heads: —

1st. On the Production of Chlorophyl by yellow light.

2nd. On the Movements of Plants towards indigo light.

3rd. Some applications of these facts to vegetable physiology.

Part I. On the Production of Chlorophyl by yellow light.

2. It is a fundamental fact in botany that light is necessary
to the formation of chlorophyl. Von Humboldt adduced cer-
tain exceptions to this law, in the case of plants found in the
mines of Freyberg, and with Senebier ascribed the green
matter to the action of hydrogen gas. But the experiments
of the latter have failed in the hands of DeCandolle, and a
series instituted by myself, and conducted with great care,
were equally unsuccessful. On the other hand, .Humboldt
succeeded in greening a plant of Lepidium sativum, raised in
darkness, by the light of two lamps, and DeCandolle obtained
the same result with six Argand lamps.

3. The investigation has been subsequently confined to the
name of the ray which produces the chlorophyl. Formerly
it was tacitly admitted that the chemical or blue ray was most

* Communicated by the Author.
Phil. Mag. S. 3. Vol.24. No. 156. Jan. 1844. B

2 Dr. Gardner on the Action of Yellow

active. M. Morren, in 1832, and Dr. Daubeny (Phil. Trans.
1836) arrived at the conclusion that the activity was as the
luminous power of the rays respectively. The next investi-
gator, Dr. Draper (Journal of the Franklin Institute, 1837),
obtained better results in yellow than blue light. Mr. Hunt,
in 1840 (Phil. Mag., Apr.), resumed the question, and pub-
lished the most decided results (p. 272), to the effect, that blue
light alone causes the green colour of plants, and that the
yellow and red rays "destroy the vital principle in the seed."
In 1841 he was one of a committee appointed by the British
Association to report on this subject, and in a subsequent con-
versation, at the late meeting of that body, has repeated his
statements. Being the last writer, his results have given a
prominence to the doctrine that chlorophyl is produced by
the blue rays, so as to mislead Prof. Johnston in his Agricul-
tural Lectures, and Prof. Graham (Chemistry, p. 1013).

4. In September 1840 I repeated Mr. Hunt's experiments
in Virginia, and obtained dissimilar results. A known number
of turnep-seeds were sown, and every grain germinated in the
yellow and red rays. The greenest plants were found in
yellow light. Every condition was favourable and the results
pronounced, but my reason for deferring the publication arose
from a conviction that the use of solutions and coloured glasses
was objectionable, and that no perfect results could be obtained
except with the spectrum. Plants exposed to light which has
permeated cobalt glass, are not placed in the blue rays, but
in red, yellow, green, indigo and violet, in proportions differ-
ing with the tone of colour and thickness of the material. The
effect may therefore be produced by any of these rays, or by
their peculiar combination*.

5. I shall not attempt to explain the discrepancy between
my results and those of Mr. Hunt, for I do not esteem re-
searches made with coloured media of any value in this branch
of vegetable physiology. It is well to remark, however, that
in treating of the germination of cress-seed behind the blue,
green, yellow and red media, he states, " that the earth con-
tinued damp under \\\e green and blue fluids, whereas it rapidly
dried under the yellow and red" (p. 271). This difference
would have been considered sufficient to retard or " destroy ?"
germination by most persons.

6. Other engagements in 1842 interfered with my design
of examining the question with the spectrum, and it was not
until July 1843 that such arrangements were made as are ne-
cessary to the prosecution of the subject.

7. The Apparatus.— A beam of the sun's light was directed

* See Sir J. F. W. Herschel, Phil. Trans., part i. 1840, on the «' Combined
Action of Rays of different degrees of Refrangibility," p. 24.

and of Indigo Light on Plants. 3

by a heliostat placed outside my window, along a square tube
of wood passing through the shutter. The inner extremity
of the tube was closed, and contained near its end a flint glass
equilateral prism, one inch on the side and six inches in length,
with the axis adjusted perpendicularly. The dispersed light
passed into the chamber through an aperture in the side of
the tube. All that portion of the beam which exceeded the
breadth of the prism was cut off by a diaphragm. The ob-
ject of these arrangements was to render the room perfectly
dark. The experiments were performed in Virginia, lat.
37° 10' N., and continued from July 6 to October 1, during a
season of unusual brilliancy and temperature.

8. Arrangements for the experiments. — Seedlings of tnrneps,
radish, mustard, peas, several varieties of beans, and the fol-
lowing transplanted specimens were used : — Solatium nigrum
el virginianum, Plantago major et minor, Polygonum hydro-
piper, Chenopodium rubrum, Rumex obtusifolius. They were
placed in boxes with partitions, or planted in jars, and grew in
darkness until ready for experiment, -so that they acquired a
yellow colour. The number of plants exposed to each ray
averaged one hundred, when the smaller seeds were used, and
the result indicated was obtained by a comparison of the whole.
The age of seedlings is a matter of moment; those which are
young and from 1 to If inch, in the case of turneps, were most
sensitive ; indeed, these plants were found to give the best re-
sults, and used almost exclusively after the first month. The
spectrum was allowed to fall on the specimens at fifteen feet
from the prism, and undecomposed light closed out by screens.
Each ray acted in a separate compartment.

9. The following extract of one experiment will show some
further details : —

August 13th. — Five jars, A, B, C, D, E, containing each
about one hundred turnep-seedlings, were placed respectively
in the orange, yellow, blue, indigo and violet rays, at 9 a.m.
Day, bright; temperature in shade at noon 80° Fahr., in the
sun 95°. Duration of sunshine 6| hours. Result at 3^ p.m.
Height of plants at nine o'clock a.m. third column of table.

Jar.

A
B
C
D
E

Light.

Orange.

Yellow.

Blue.

Indigo.

Violet.

Height at 9-

1 inch
1 ...

H ...
l ...
H ...

Effect.

Good green.
Full green.
Slight olive.
Yellow.
Yellow.

Order.

* The fifth column contains a comparative estimate of the depth of
colour, assuming unity as the highest value on this scale, the plants in blue

B2

4 Dr. Gardner on the Action of Yellow

August 14th. — The same plants, with the addition of a fresh
crop F in the green ray. Exposure from 9 a.m. to 3 p.m.
to 6 hours' sunshine. Temperature in shade, noon, 85° Fahr.
and 105° in the sun. Result at 3 p.m.

Jar.

Light.

Height at 9.

Effect.

Order.

A

Orange.

2\ inches.

Full green.

2

U

Yellow.

2} ...

Perfect green.

1

C

Blue.

3 ...

Slight green.

4

D

Indigo.

3 ...

Yellow.

0

E

Violet.

3* ...

Yellow,

0

F

Green.

1 ...

Fair green.

3

The leaves of A and B were developed. Experiment con-
cluded after 30 hours, of which 12^ were sunshine and 17|
darkness. The greater altitude of the plants in the indigo
and violet rays is due to the slowness of exhalation by vege-
tables in those colours, an effect, not of light, but of heat. In
this instance no effect whatever was produced on the original
yellow colour of the seedlings in the indigo and violet light,

10. The subjoined table contains the comparable points of
six similar experiments. The first column gives the number
of the experiment; the second the plants used; the third the
number of hours of sunshine; fourth, the whole duration of
the experiment; and from the fifth to the thirteenth column,
the rays of the spectrum ; the figures placed in the last spaces
indicate only the order of colour in the particular observation.
The sign of minus is introduced whenever the effect of the ray
was not tested, or the result was defective.

Table showing the active and inactive rays of the spectrum
in producing the green colour of plants.

Plants.

Turneps

Beans, &c. ..
Turneps, &c.

Turneps

Turneps

Turneps

22
14

8
23
17-5

5-5

109
95
69

101

52

6

Active rays.

Inactive rays.

0 0

In experiment 5 the blue ray produced a green colour, but
the usual effect was a light olive. The indigo, violet and la-
did not become green, and therefore the value is negative; but there was
a visible alteration, designated olive, and indicating the tint which vegetables
assume in passing from the yellow colour, produced in darkness, to green.

and of Indigo Light on Plants. 5

vender portions were always inactive, although several experi-
ments were continued until the plants faded.

11. Under favourable circumstances it requires a long ex-
posure to develope chlorophyl. The shortest period I wit-
nessed was in a crop of turnep-seedlings, which required two
hours in the centre of the yellow, but frequently six or more
hours were necessary. In a full Virginia sunshine it requires
more than an hour to produce the same effect.

The colour acquired is not fugitive. It has been observed
scarcely changed after seventy-two hours' darkness in turneps,
and seven days in beans. Plants from the field preserve their
colour sometimes for three weeks, but finally become yellow.

1 2. The fact established by these observations is, that the
less refrangible rays are most active in producing the green
colour of plants. It is not stated that the blue, &c. rays will
not effect this change in time, but that they are singularly in-
active.

13. The maximum action is in the yellow light. — For the
purpose of obtaining a measure of the comparative activity of
the different rays, the following experiment was made : — the
spectrum of a circular beam of light, three-fourths of an inch in
diameter, was received upon a double convex lens of three
feet focus, placed near the prism. The dispersed rays passed
through a chink of a quarter of an inch into a camera, and
each fell into a separate compartment, containing a few turnep-
seedlings, situated near the focus of the ray. The place of
the extreme red and central yellow rays was determined
through cobalt glass, and the whole spectrum divided into the
spaces given by Fraunhofer for the width of each colour. The
arrangements being carefully adjusted the plants were exa-
mined at intervals, by allowing a little diffused light to fall
upon them, and excluding the spectrum; in this way the
number of hours was obtained in which a given ray produced
a certain amount of colour. The depth of green was esti-
mated by carefully comparing the plants with a selected spe-
cimen ; in this I was assisted by a friend whose eye is well
skilled in distinguishing between shades of colour.

mi CO

1 4. The best result gave for the yellow 3^ hours, the orange
4| hours, and the green 6 hours ; the plants were selected from
the centre of the groups, and all the measures obtained on the
same day during uninterrupted sunshine. The observation
was continued until 17y hours sun-light had acted upon the
plants in the blue, which then acquired a tint estimated at one-
half that of the test. In another experiment, the indigo, violet
and lavender spaces exhibited no plants which had changed
in 23 hours.

6 Dr. Gardner on the Action of Yellow

15. From the experiments I conclude that the centre of the
yellow ray is the point of maximum effect in the production of
chlorophyll and that the action diminishes on either side to the
termination of the mean red and blue.

1 6. In this stage of the subject an interesting question sug-
gests itself; is the active agent light ? some form of chemical
ray ? or heat ? To discover whether it was due to tithonicity*;
I placed a crop of turnep- seedlings in a box, illuminated ex-
clusively with light which had traversed a solution of bichro-
mate of potassa, sufficiently concentrated to absorb all tithonic
rays. The plants became green in about c2\ hours, so as to
indicate, not only that the detithonized rays were capable of
producing green matter, but of doing so with remarkable acti-
vity. Hence the formation of chlorophyl is not due to titho-
nicity.

Nor is heat the active agent, for the maxima of heat which

has traversed flint glass do not correspond with the rays which

produce the principal action on etiolated plants. Chlorophyl

is therefore produced by the imponderable light, as distinguished

from all other known agents found in the sunbeam.

Part II. On the Movements of Plants towards indigo light.

] 7. Among the most interesting phaenomena of plants is the
apparent instinct of bending towards light. The character of the
movement may be seen with ease, by exposing a crop of turnep-
seedlings near the light of an Argand lamp provided with an *
opake shade. If they be adjusted in such a manner as to have
the leaflets slightly above the lower margin of the shade, the
whole will be found inclined forwards in two to four hours.
It is this movement I propose to examine.

18. All erect plants obtained in darkness, when exposed to
the solar spectrum in distinct compartments, incline them-
selves forward towards the prism. It is therefore an effect
which is produced in every variety of light, even obscure light
produces it; therefore, in researches on this subject, every
precaution must be taken to darken the place of experiment.
The amount of bending frequently exceeds 90°, and a move-
ment of the free extremity of the stem through 1 to 1^ inch
from the perpendicular is not unusual in turnep-seedlings.

19. If the young plants be exposed to a spectrum produced
as in art. 13, in a box without compartments, after a time they
will be found inclined diagonally towards a common axis;
those in the red, orange, yellow and green bending towards
the indigo, and the plants of the violet and lavender moving
to meet them. When a large spectrum of fourteen inches was

* See Dr. Draper's paper in this Magazine, December 1842, p, 457.

and of Indigo Light on Plants. 7

used, and the seedlings exposed for five hours, they were so
inclined as to suggest the appearance of a field of growing
wheat, blown by two winds to a common point. If the expe-
riment were sufficiently prolonged, some of the plants from
either extremity of the spectrum interlocked in the direction
of the axis.

20. This axis is in the direction taken by Fraunhofer's indigo
rat/ in passing from the prism to the plants. — The plants grow-
ing in indigo light inclined directly along it, but those of the
red, orange, &c. did not move towards the radiant in the
prism, but along a diagonal, inclined in part to the plants il-
luminated by the active rays, which were much nearer than
the prism. The amount of this lateral inclination diminished
as the plants were nearer the axis, so that those illuminated
by blue, violet and lavender were little deflected from a line
drawn from their place of growth to the radiant. Seedlings
in the red, orange and yellow rays frequently bent to such an
extent as to cause their summits to pass through the adjoining
coloured space.

21. The secondary (lateral) inclination, remarked above,
did not occur when the radiant was a reflected image of the
spectrum, which was not allowed to fall on any of the plants.
If the mirror reflected neither of the more refrangible rays,
the plants appeared to be inclined to the light immediately
before them.

22. These experiments satisfied me that the active force
was in the indigo ray, and the intensity of the light necessary
to produce deflection was extremely feeble, so that an amount
inappreciable to the eye (which is an admirable measure of the
brilliancy, but incapable of estimating the effect of quantity)
would, after a lengthened exposure, cause considerable deflec-
tion. Indeed, the phenomenon is so little dependent on the
brilliancy of light that very little seems to be gained by con-
centrating the rays beyond a certain point. There is there-
fore sufficient activity in each prismatic colour to produce
bending, if sufficient time be allowed. The movement is
therefore a result depending upon the absorption of light.

23. As this is an entirely new subject, it is thought expe-
dient to advance some further evidence concerning the posi-
tion of the deflecting force. For this purpose the spectrum
was allowed to fall upon a screen, perforated by two similar
apertures, in such positions as to allow the red ray to pass
through one and the indigo through the other. Behind the
screen a box was placed containing four jars of turnep-seed-
lings, arranged along a line occupying the centre between the
intermitted rays. The light passed through the box without
any reflection, and was stifled by black cloth when it fell upon

8 Dr. Gardner on the Action of Yellow

the further extremity. All the plants commenced bending in
a short time, and in two hours the nearest groups were in-
clined forwards 90°, and laterally 50° towards the indigo aper-
ture, the edges of which formed the radiant. In three hours
the second crop exhibited the same movement, and so with
the plants of the third and fourth jar. At the conclusion of
the experiment, in §\ hours, all were bent forward at about
90°, and each group inclined towards the indigo aperture, in
a direction indicated by drawing a straight line from the plants
to the radiant, ttot a plant inclined towards the red ray,
although half the collection were nearer to it than to the more
refrangible light.

With similar arrangements, the yellow, orange and green
rays were examined in contrast with the indigo, with the fore-
going result in every case. The time necessary to develope
a satisfactory lateral inclination from the green rays is greater
than in the experiments made between the less refrangible
rays and indigo.

24. The same results were produced when the radiants were
reflected images. The extent to which the influence of the
active light is felt was frequently surprising; in some of the
observations pea plants were situated four feet from the indigo
and within half an inch of the yellow, red, or orange radiant,
notwithstanding which they inclined towards the most refran-
gible rays. In these researches the mirror was situated so as
to reflect no prismatic light upon the plants.

25. That no doubt may rest on the place of the soliciting
force another arrangement was used. The instrument figured
by M. Pouillet {Elemens de Phys., &c, tome i. fig. 218) for
examining the effect of combinations of rays of light in pro-
ducing colours was taken. Red rays were received on one
mirror and indigo on another, and the two so far inclined as
to cause the rays to intermix at a place about three inches in
advance of the instrument. A jar of turnep-seedlings was then
placed so as to receive the compound light in its centre, the
plants being illuminated in part by the red, indigo and purple
rays. In two hours the movements were considerable and
somewhat complex. Every plant lighted by the indigo rays
were inclined directly to that radiant. Those which received
red light were bent to the central purple, and none to the red
radiant. But many seedlings at first in the red inclined them-
selves towards the purple, and afterwards, having become
fully illuminated thereby, commenced a lateral movement to-
wards the indigo radiant, so that, at the close of the experi-
ment, their stems exhibited two inclinations, one in a vertical
and the other in a horizontal plane.

26. Plants raised in darkness, as well as those which were

and of Indigo Light on Plants. 9

green, were used in the preceding observations ; but the sen-
sibility of the former greatly exceeds that of the latter. Indeed,
plants that have been exposed to light for several days become
sluggish in their movements, and the phsenomenon probably
ceases in parts which are ligneous. In the seedlings submitted
to examination, the motion was found to take place in conse-
quence of an action impressed upon the stem only, for the re-
moval of the leaflets did not alter the result. A still more
remarkable fact was observed in all the cases examined; that
after complete bending plants erect themselves again when
placed in darkness, at least in situations so dark as to appear
entirely deprived of light. This effect is best seen in seedlings
which have never been exposed to the direct rays of the sun,
for, after full and lengthened exposure, it diminishes to a
minimum. The action of light in producing movement seems
therefore to be transient, that is, it is not accompanied with a
permanent change of structure in the plant.

27. From all the foregoing experiments it is demonstrable,
that the force which constrains the movements of plants toxvards
light has its maximum in the indigo ray.

28. But the solar beam contains a number of agents, one
of which more especially developes itself in this part of the
flint-glass spectrum, acting upon argentine compounds with
great effect. Dr. Draper has discovered the existence of
chemical action, distinct from the rays of light or heat, through-
out this spectrum, and terms the agent which produces it ti-
thonicity. Is that bending of plants here considered produced
by the tithonic rays? by heat? or by light?

29. The investigation of these important problems has cost
me much labour, but the following results will show that a
satisfactory solution has been attained.

A trough of plate glass containing persulphocyanide of iron,
which has the property of absorbing the tithonic rays of the
indigo space, and allowing indigo light to pass, was placed
before a small aperture made in the end of a suitable box.
The proper place for the whole was determined by receiving
the analysed spectrum on a Daguerre plate resting against the
box. In a few minutes two stains were observed, with an in-
terval corresponding to the indigo light between them. The
inactive space was marked upon the wood, and a perforation
made without changing the adjustments. Plants placed in the
box were bent in two hours, whilst a crop illuminated by
indigo rays, which had not been transmitted through the so-
lution, did not move with much greater activity, although one
crop was exposed to the maximum of the indigo tithonic ray
and the other placed in detithonized light.

10 Dr. Gardner on the Action of Yellow

30. Solution of bichromate of potash intercepts nearly all
tithonic matter, but permits the free passage of luminous rays.
A crop of turnep-seedlings was introduced into a box and illu-
minated by the yellow rays of the spectrum analysed by this
solution. A Daguerre plate was also introduced, to serve as
a test of chemical action. In 2^ hours the plants were all
equally bent, and the plate but slightly stained at one side. A
group of similar plants exposed in the same place, without the
solution, were inclined in a period of time not materially dif-
ferent. If the bending had been due to tithonicity, the seed-
lings should have moved towards the place where the plate was
stained.

31. The tithonic activity of rays transmitted through the
above solution, from an Argand lamp, is diminished to less
than 2^olh Part> as measured by Dr. Draper's instrument.
But plants were bent in light from this source which had tra-
versed the solution in a period not much greater than that re-
quired in the full blaze of the lamp. This result alone is
abundantly sufficient to decide the question, and show the
total inactivity of the tithonic rays in producing these vege-
table movements.

32. That the bending is not due to heat appears from the
following considerations : — the action is greatest in those parts
of the spectrum which give evidence of least heat. The axis
is approached on one side by the red, orange, yellow and
green, and by the violet and lavender plants on the other,
which is a phaenomenon that cannot be explained on the sup-
position that heat is the active agent. Plants shut from the
light of an Argand lamp by a plate of copper foil do not in-
cline to the warm metal.

Finally, the moonbeams, even without condensation, are
capable of producing extensive bending in one or two hours.
This result is conclusive of the question, for no trace of ca-
loric can be found in the moon's light.

33. As far, therefore, as the presence of heat can be deter-
mined by thermoscopes, or the tithonic rays by argentine
compounds, and the union of chlorine and hydrogen, we are
justified in concluding that the movements of plants are ef-
fected by a totally different agent. Light only remains in the
spectrum, so far as we know, and to it therefore I refer the
movements under consideration.

34<. This conclusion is of deep interest, inasmuch as it is
thejirst case of a movement, perceptible to the eye, being traced
to the unaided action of light. That this imponderable pro-
duced molecular changes was readily admitted, but its influ-
ence in bringing about palpable movements of considerable

and of Indigo Light on Plants. 11

extent has never been suspected. In the irritability of the
iris physiologists have always seen the influence of nervous
matter, but in plants no such agent exists to complicate the
phaenomenon, and therefore the action is due to light only.

In this newly-discovered property light is also more closely
assimilated to the other imponderables, for both heat and elec-
tricity are capable of producing motion.

Part III. Some applications of the preceding facts, Sfc.

35. Numerous applications to vegetable physiology will
suggest themselves to the reader, but it is my purpose to treat
only of the following.

The intimate relation which exists between the rays which
produce chlorophyll the decomposition of carbonic acid, and the
luminous spectrum. — The maximum for the formation of green
matter has been shown to reside in the yellow ray. Dr.
Draper (in this Magazine, September 1843) discovered the
maximum action for the decomposition of carbonic acid to be
between the green and yellow, or more correctly in the yellow.
Sir W. Herschel and Fraunhofer placed the maximum for
light in the same space.

36. The relation goes further, for if the quantities obtained
by Dr. Draper for decomposing action, as measured by libe-
rated gas; Fraunhofer for illuminating power determined by
the eye ; and my estimate, obtained in time and by the eye,
be rendered commensurable and tabulated, they will give
quantities nearly allied. To produce such a table I assume
ail the maxima equal to unity. My results being given in
time and theirs in effect, the inverse proportion is taken for
each value given in article 14-.

Table showing the. force of the solar rays in producing the green
colour of plants, the decomposition (f carbonic acid, and illu-
mination.

Places examined.

Production of
chlorophyl.

Decomposition of
carbonic acid.

Illuminating
power.

Line B

0

0
0091

0

032

094

Comm. of orange .
Line D

•555

•640

Centre of orange..
Centre of yellow..
Line E

•777
1-000

1-000

1000

•480

Centre of green...
Line F

•583

•170

Centre of blue ...
End of blue

•100

0027
0
0

0
0

m ,

031
0056

12 Dr. Gardner on the Action of Yellow

37. Upon projecting these numbers, which, although not
rigorously correct, are very good approximations, the unity of
the active agent will be more strikingly exhibited. Let the
axis of abscissas be divided into intervals corresponding to
Fraunhofer's coloured spaces, and the positions of the mean
places of the dark lines be marked from Mr. Powell's recent
work on dispersion. The ordinates are from the preceding
table; Fraunhofer's estimates are indicated by a bold line,
Dr. Draper's by dots, and my own by an interrupted line.

Fig. 1.

Had more points in these figures been determined, there is
no doubt they would have coincided precisely. It is not to
be forgotten that these results were obtained in places many
hundred miles apart. They determine, what hitherto has only
been conjectured, that the greening of plants and decomposi-
tion of carbonic acid are produced by the same agent, which
is also the active imponderable in producing vision, a pheno-
menon in no way similar, as suggested by M. Moser, to the
change of Daguerre's plate, which is a tithonic action.

The dependence of the depth of green colour in foliage
upon brilliant light is also shown. The statements of tra-
vellers, in regard to tropical vegetation, confirms this conclu-
sion.

38. Chlorophyl, the body generated in the yellow leaflets
of plants, raised in darkness by the action of light, is a hydro-
carbon of the nature of wax. Whether it be produced by

and of Indigo Light on Plants. 13

decomposition of carbonic acid, or be the deoxidized yellow
matter, or some other substance, as dextrine, already present
in the leaf, is unknown. The latter view, applied to the for-
mation of oils and fats in animals by Liebig, is probably cor-
rect; by adopting it we are relieved from all difficulty in regard
to the supply of hydrogen in plants, for the evidence, that
water is decomposed in their structures, is by no means con-
clusive. In the formation of oils in seeds it is clear that the
deoxidation of sugar occurs, for we have a liberation of car-
bonic acid from the petals and a destruction of the organic
matter.

Subsequently to the production of chlorophyl carbonic
acid is decomposed by light, and this function, directly or in-
directly, is sufficient to generate all organic matter. Hence
the existence of all organic matter is due to the light of the
sun.

39. On the destruction of chlorophyl by light. — The pro-
duction of green matter by the yellow rays leads us to infer
its destruction by the red and blue. Sir J. F. Herschel
(Phil. Mag., Feb. 1843) found that the juices pressed from
the leaves of plants are acted upon by the spectrum with much
uniformity. In the case of elder leaves (fig. 8) there was a
strong maximum, producing a nearly insulated solar image at
— 11*5 of his scale, or nearly at the end of the red rays; the
action thence was feeble, with two minima at — 5*0, + 6*8,
with a slight intermediate maximum at (0*0) the yellow ; and
beyond these, or about the termination of the green, the ac-
tion again increases, reaches another maximum at + 20*0,
which corresponds to the centre of Fraunhofer's indigo, after
which it declines to a point beyond the violet + 45*0. I have
been thus precise in giving his result, because my experi-
ments made with sethereal solution of chlorophyl, from grass
leaves spread upon paper, gave similar spectra. There are
two points however which it is necessary to discuss.

The first action of light is perceived in the mean red rays,
and it attains a maximum incomparably greater at that point
than elsewhere; the next point affected is in the indigo, and
accompanying it there is an action from + 10*5 to + 36*0
(of the same scale) beginning abruptly in Fraunhofer's blue.
So striking is this whole result, that some of my earlier spectra
contained a perfectly neutral space from — 5 0 to + 10*5, in
which the chlorophyl was in no way changed, whilst the solar
picture in the red was sharp and of a dazzling white, and the
maximum of the indigo was also bleached, producing a linear
spectrum, as follows : — , in which the orange,

yellow and green rays are neutral ; these it will be remembered

14 Action of Yellow and of Indigo Light on Plants,

are active in forming chlorophyl. Upon longer exposure the
subordinate action along the yellow, &c. occurs, but not until
the other portions are perfectly bleached.

In Sir John Herschel's experiments there remained a sal-
mon colour after the discharge of the green. This is not
seen when chlorophyl is used, and is due to a colouring matter
in the leaf soluble in water, but insoluble in aether.

40. No ground therefore exists for the theory, that the
autumnal tint of leaves is due to the residual after the de-
struction of the green colour. The xanthophyl, which imparts
the yellow, depends on an organic change of chlorophyl,
which Berzelius could not imitate (Journ. de Pharm., Juillet
1837).

Some observations made with a view of determining the
action of indigo light on the green of living plants, brought
me to the conclusion that it faded into a yellowish green
colour under its influence ; but I will not speak positively.
Plants do, however, lose all their greenness in a dark place
after a greater or less time, and become of the colour of seed-
lings raised without light. In this result my experience is at
variance with the statement of Macaire Princep : " les feuilles
d'une plante conservees a l'abri de la lumiere s'en detachent
colorees vert" (in Berzelius, Chimie, t. 6. p. 42).

41 . In the bleaching of chlorophyl, as well as in its produc-
tion, the active agent is light, for it will take place behind a
medium excluding tithonicity, and the action has no connec-
tion with the maxima of the calorific spectrum.

V2. The coincidence shown between the illuminating power,
activity of decomposition of carbonic acid, and greening effect
of yellow light, is conclusive of the discussion respecting the
rays which are favourable to the growth of vegetables. The
blue rays cannot be the best, as originally affirmed by Sene-
bier, and subsequently maintained by Mr. Hunt, nor would a
conservatory glazed with cobalt glass answer the expectations
of Professor Johnston.

4-S. It is impossible to conclude without calling the atten-
tion of physiologists to the remarkable fact proved in the
second part of this paper, that indigo light possesses a solicit-
ing power capable of governing the direction of the stems,
peduncles, &c. of plants; an action accomplished by light,
incomparably feeble in comparison with the yellow rays. The
blue of the atmosphere is scarcely less intense when compared
with the sun's beams. Does not the colour of the sky, there-
fore, regulate the upright growth of stems to a certain extent ?
Is it not in virtue of the soliciting force therein that plants con-
tinue to grow erect whenever other disturbing forces are in equi-

Prof. De Morgan on Continued Fractions. 15

librio? These questions might be investigated with profit
were not this communication already too extended.

44. It is proper to state, however, that DeCandolle's theory
of the bending of plants towards light has been fully disproved,
inasmuch as it is an effect due to the indigo rays, which have
not power to decompose carbonic acid and produce lignin,
&c. {Man. Soc. d'Arcueil, 1809, p. 104).

In conclusion, it appears that the following facts have been
established : —

1st. That chlorophyl is produced by the more luminous
rays, the maximum being in the yellow.

2nd. This formation is due to pure light, an imponde-
rable distinct from all others.

3rd. That the ray towards which plants bend occupies the
indigo space of Fraunhofer.

4th. This movement is due to pure light, as distinguished
from heat and tithonicity.

5th. That pure ligh* If capable of producing changes which
result in the development of palpable motion.

6th. The bleaching of chlorophyl is most active in those
parts of the spectrum which possess little influence in its pro-
duction, and are complementary to the yellow rays.

7th. This action is also due to pure light.

We have, therefore, an analysis of the action of every ray
in the luminous spectrum upon vegetation. The several ef-
fects produced are not abruptly terminated within the limits
of any of the spaces, but overlap to a certain extent, a fact
which coincides with our experience of the properties of the
rays. Whilst heat and tithonicity are capable of causing the
union of mineral particles, /^///appears to be the only radiant
body which rules pre-eminent in the organic world. To the
animating beams of the sun we owe whatever products are ne-
cessary to our very existence.
New York, October 14, 1843.

II. On the Reduction of a Continued Fraction to a Series.
By A. De Morgan, Professor of Mathematics in Univer-
sity College, London*.

ri^HE mode of reducing a continued fraction to a series has
A not received much attention, but as every specimen of
law of development may contain useful hints, the following in-
vestigation will perhaps interest the mathematical reader.

It is required to develope into a series of powers of x the
continued fraction

* Communicated by the Author.

16 Prof. De Morgan- on Continued Fractions.

'6

a9x a.^x a a bx ex a

-, &c, or - -— — - — ~, &c,

*1+ ^2+ h+' *' 1 + 1 + 1 +'

to the second of which the first may be easily reduced. In
reasoning it may be proper to use av a2, a3, &c. ; in working,
a, b, c, &c. will be found more convenient. If

a a . , x a . , a , nx

A„ = rr -iV' &c" A«+i - tt m~! &c"

we have An (1 + AM+1 x) = an. If then/(aTO+1, *># &c.)

be called the advanced form oi\f (a , an, &c), and if A be

taken to be P0 + P1 x + P2 x* + , &c. ; and if Q0, Q1? &c. be
the advanced forms of P0, Px, &c, we have, from the equation
between Al and A2,

P0 = av P, = P0 Q0, P2 = P0 Qx + Vt Q0, &c.

PW + 1 = P0 Qn + P! Q.-1 + - + Pn-1 Ql + P« Qo,

which gives an easy law of formation for a few terms. Thus
we have, using a> b, &c. for av ff2» &c,

P0 = a, Px = a b, P2 = a (b c) + a b (b) = a b c + a &
F3 = a{bcd + be*) + ab\bc) + (abc + aW)b,

= abcd + abc2-{-2ab'2c + ab3,
P4 = abcde + abed2 + <2abcid + abc3 + 2 a Wed
+ 3a62c2 + 3ab3c + ab4.

The results of this method would give little encouragement
to attempt finding the law of these terms, which is, however,

very simple, as follows : let such an expression as ab cy d ...
in which the order a, b, c, d, §tc. is unbroken, be called conse-
cutive ; and let m denote the coefficient of the mth power of

x in the development of (1 + xf\ then will the coefficient Pjbe

the sign 2 extending to every way in which /3 -f y -f 8 + ...
= I, on condition only that every term shall be consecutive,
that is, that no one of the set /3, -y, &c. shall vanish, unless all
the subsequent ones vanish also. This law will be evident on
a very slight consideration of another mode of development,
namely, that of a ■+■ (1 + bx\ followed by the substitution of
b ■+■ (1 + ex) for b, followed by that of c ■+■ (1 + dx) for c,
and so on.

The number of terms in P. must be 24- , since they are
formed by writing over b, c, d, &c. exponents /3, y, &c. in
every possible way and order in which i can be /3 -f- y + ...

Action of Alkalies on Wax. 17

without any one of the set /3, y, &c. being nothing. The sum

of the coefficients is half the coefficient of # "*" in V ( I + 4 a?),
as is easily proved.

The readiest way of forming P. , . from P. is as follows: —

(1.) Put on the next letter to every term of P., and also repeat

the last letter of each term once more than it occurs already ;
thus fli2c gives ah* c d + ab* e*. (2.) Put all the results of
(1.) together, and correct or introduce coefficients by the law
above ascertained.

It is also worth notice that the portions of P. which do not

contain any letters beyond a given one foliow the law of a re-
curring series. Thus, if Pw . signify all that portion of P in

which nothing beyond k occurs, we have

P„,* = 4P»-M' P„,C=(A+<)P„-11<;.

and so on ; the coefficients (b + c + d), &c. being derived
from the denominators of the ordinary approximations.

The mode thus given of turning a continued fraction into a
series is not so easy in practice as the one derived from invert-
ing the process of turning the ratio of two infinite series into
a continued fraction ; but the law is worth consideration, the
more especially as, from the presence of none but consecutive
terms, it cannot be directly connected with Arbogast's methods.
This is the reason why the reader looks in vain for anything
about continued fractions in the Calcul des Derivations. The
most complete account I know of continued fractions is in
Eytelwein's Grundle/iren, &c, in which, however, the inverse
method occupies only six pages, the direct one eighty-nine ;
and no general law is given for the series considered in this
paper.

III. On the Action of Alkalies on Wax. By Robert
Warington and W. Francis, Esq.*

FEW subjects have of late engaged so much the attention
-*- of chemists as that relative to the formation of fat in the
animal organization, a subject fraught with results of the high-
est importance both to science and its applications to rural
ceconomy.

Two theories have been proposed to account for its origin : —

* Communicated by the Chemical Society; having been read May 16
1843.

Phil. Mag. S. 3. Vol. 24. No. 156. Jan. 1844. C

18 Mr. Warrington and Mr. Francis

The one by M. Liebig, which supposes that the fat is pro-
duced by the conversion of sugar, starch and other non-ni-
trogenous bodies during the process of digestion, as detailed
in his paper on this subject published in the Society's Me-
moirs, vol. i. p. 164- ; a view which is supported by various
analogous processes and decompositions with which chemists
are already familiar, as for instance the conversion of amyg-
daline into the oil of bitter almonds, of salicine into oil of
meadow-sweet, and also the production of cenanthic aether in
the fermentation of amylaceous substances, which moreover
has recently been shown by M. Wohler to be readily con-
verted by distillation into margaric acid. The other theory by
MM. Dumas, Boussingaultand Payen*, according to which no
production of fat takes place in the animal frame, but that it is
contained already formed in the various products of the vege-
table kingdom, which generally serve the purposes of food.

In support of this latter view, great importance has been
placed on some recent observations of M. Lewyfj communi-
cated to the French Academy of Sciences, in which it is stated,
that when purified bees'-wax is boiled with a concentrated so-
lution of caustic potash, or when cerine, one of the principal
constituents of wax, is heated with potash and lime at the tem-
perature of a metallic bath, it undergoes saponification, and
affords a combination entirely soluble in water, and from
which acids separate a fatty body having the properties and
composition of stearic acid.

This statement, apparently so entirely at variance with what
had hitherto been published on the nature of this substance
and its behaviour towards the, alkaline bases, and the ease,
moreover, with which, if confirmed, pure stearic acid might
in future be obtained, induced us to repeat some of the ex-
periments of M. Lewy bearing on this point.

Before, however, detailing the results at which we arrived,
it will perhaps be well to give in brief outline the data ob-
tained by former investigators.

According to the researches of MM. Boudet, Boissenot J,
and Ettling§, wax is a mixture of cerine and myricine, which
may be readily separated from each other by means of alco-
hol, the myricine being nearly insoluble in that medium : the
cerine which is deposited on the cooling of the alcoholic solu-
tion is itself a compound body consisting of ceraine and mar-
garic acid ; these may be separated by treatment with caustic

* Annates de Chimie et tie Physique, t. iv. p. 208.
f Comptcs Rendus, No. xiv. April 3, 1843, p. 675.
X Journ. de Pharin* vol. xiii. p. 43.
§ Annalcn der Pharmacic, vol. ii. p. 253.

07? the Action of Alkalies on Wax. 19

potash, which forms a soap with the margaric acid without
acting at all on the ceraine. Ettling analysed ceraine and
myricine, and found them to be isomeric, and composed, in
100 parts, of—

Ceraine. Myricine.

Carbon . . . 80*44 80*01

Hydrogen . . 13-75 13-85

Oxygen ... 5-81 6*14

MM. Hess* and Van der Vleitf regard wax as a simple
substance, which in the common yellow wax is in combination
with a colouring matter, and in the white wax with cerainic
acid, composed of

Carbon . . . 81-52

Hydrogen . . 13-23

Oxygen . . . 5*25

Hess states that it contains no margaric acid, and does not

afford either cerine or ceraine.

The experiments of Ettling, as to wax being a compound
body consisting of cerine and myricine, are confirmed how-
ever by M. Lewy, who finds them to be isomeric, and com-
posed, in 100 parts, of —

Carbon . . . 80*31

Hydrogen . . 13*38

Oxygen . . . 6*30

Berzelius, in the third German edition of his < Manual of

Chemistry,' vol. vi. p. 513, states, that wax is converted into

a kind of soap by caustic alkalies, but the combination formed

is of difficult solution in water, and separates in a cream-like

form on the surface of the liquid ; that this cream may be

melted to a very hard soap, but that acids separate the wax

with nearly unaltered properties.

On boiling wax for six hours with caustic potash we ob-
served exactly the appearances described by Berzelius; it was
evidently acted upon, increased in bulk, and a curdlike mass,
sparingly soluble in water, separated on the top of the liquid.
On melting wax and then dropping fused caustic potash into
it, a small quantity of gas is given off, and the whole mass in
a few seconds is converted from a liquid state into a thick,
gelatinous, amber-coloured soapy substance, which was found
to be almost entirely soluble in a large quantity of water. It
was separated from the solution, in a curdy state, by the
addition of common salt, washed, redissolved and hydro-
chloric acid added ; this threw up a colourless oily liquid,

* Annal. der Pharm. xxvii. p. 8.
f Bulletin de Neerlande, No. xvii. 1838.
C2

20 Jetton of Alkalies on Wax.

which on cooling solidified into a waxy brittle substance.
After being well washed with boiling water to remove any
traces of hydrochloric acid, it was treated with alcohol, in
which, with the assistance of heat, it was perfectly soluble,
and on cooling separated in a crystalline state. From these
appearances, we were inclined to entertain the idea that
a conversion of the wax into stearic acid had taken place, but
the alcoholic solution of the supposed acid did not in the least
affect blue litmus paper, and when boiled with a solution of
carbonate of soda not a trace of gas was evolved. Its melting-
point was ascertained to be 74 C, and the fused mass on
cooling exhibited not the slightest trace of crystalline struc-
ture ; it could not evidently therefore be stearic acid, and such
was proved to be the case by the annexed analysis.

0*34-6 grm. of the substance, dried for six hours in the water-
bath to remove all trace of alcohol, afforded on combustion
with chromate of lead 0*427 grm. of water and 1*005 grm. of
carbonic acid, or in 100 parts, —

Carbon . . . 80*31
Hydrogen . . 13*70
Oxygen . . . 5*99

It is therefore as widely different from stearic acid as any
body can be— the alcoholic solution of which distinctly red-
dens litmus paper, expels carbonic acid from carbonate of
soda, solidifies into a mass, having a decided crystalline struc-
ture, and whose composition was found by Liebig, Redten-
bacher and other chemists, to be carbon 76*69, hydrogen
12*70, and oxygen 20*61.

On comparing the results obtained in our analysis, it will
be however immediately seen that this substance has exactly
the same composition assigned by Ettling to ceraine, with
which it is therefore isomeric, if not identical. The peculiar
characters of ceraine are that it melts at 70° C, and on cooling
forms a hard brittle mass. It is not soluble in cold alcohol,
and but very slightly in hot ; on the cooling of the alcoholic so-
lution it becomes gelatinous, but may on slow cooling be ob-
tained in a crystalline state; it is not saponifiable. The body
we have examined melts at 74° C, forms on cooling a hard
brittle waxy mass, but it dissolves readily in hot alcohol, from
which it crystallizes on cooling ; it affords a kind of soap with
potash ; it does not expel carbonic acid from carbonate of soda,
and has no acid properties. It will be seen that the results
we have obtained agree closely with those described by Ber-
zelius and by Ettling. On a future occasion we hope to bring-
before the Society an account of several curious phenomena
we have observed in our experiments on this subject ; for the

Action of Oil of Vitriol on Ferrocyanide of Potassium. 21

present, we propose for the body we have examined the name
of Pseudo-cera'itie, until by further experiments we shall have
removed the discrepancies which at present appear to exist
between its characters and those ascribed by Ettling to ce-
raine.

IV. On the Action of Oil of Vitriol upon Ferrocyanide of
Potassium. By G. Fownes, Ph.D.*

\\THEN finely powdered ferrocyanide of potassium is heated
in a capacious flask or retort with eight or ten times its
weight of concentrated sulphuric acid, the white pasty mass
first produced by the action of the acid upon the salt, gra-
dually dissolves and disappears, its solution being accompa-
nied by the disengagement of a prodigious quantity of perma-
nent gas. This gas when collected over water is colourless
and transparent ; it has a very faint garlic odour, does not
render lime-water turbid, takes fire on the approach of a ta-
per, and burns with a bright blue flame, generating carbonic
acid. When mixed with half its bulk of pure oxygen, intro-
duced into the siphon-eudiometer and fired by the electric
spark, a contraction occurs amounting to one-third part of
the whole, and the residual gas becomes almost entirely ab-
sorbable by caustic potash. These characters are sufficient
to prove that the gas in question is pure carbonic oxide.

When the oil of vitriol is first poured upon the ferrocyanide,
a good deal of heat is produced, and the odour of hydrocyanic
acid is for a moment perceptible ; this disappears, however,
as soon as the effervescence commences, and is replaced by a
trace of formic acid vapour, which may be remarked during
the whole period of the experiment. At the close of the re-
action a little sulphurous acid also may be recognised ; the
cause of this will become immediately apparent.

If, the disengagement of carbonic acid having ceased, heat
be still applied to the now fluid contents of the vessel, the
escape of sulphurous acid becomes more and more marked,
while at the same time a number of little white pearly cry-
stalline plates may be observed floating about in the boiling
liquid. These scales rapidly increase in number until, after
the lapse of fifteen or twenty minutes from the time the first
were seen, they cover the bottom of the flask to a consider-
able depth, glittering, when agitated, like new-formed crystals
of thionurate of ammonia.

When the whole has cooled, the acid may be poured from

Communicated by the Chemical Society ; having been read March 21,
843.

22 Dr. Fownes on the Action of Oil of Vitriol

the crystalline deposit, and the latter washed once or twice
by decantation with cold water and then transferred to a
paper filter. When the liquid which passes tastes no longer
strongly acid and astringent, the filter and its contents may
be spread upon a few folds of bibulous paper and placed to
dry over a surface of sulphuric acid in the vacuum of the air-
pump.

The acid liquid from which the crystals were deposited, is
found on examination to contain in solution peroxide of iron
and the sulphates of potash- and ammonia.

The new substance when dry presents a very beautiful ap-
pearance, resembling, as before remarked, thionurate of am-
monia ; under the microscope it is seen to consist of small
transparent 6-sided tables. It may be heated to above 300°
Ft without loss of weight or alteration of any kind ; at a red
heat it is slowly decomposed, leaving red oxide of iron with
some sulphate of potash. It is, as the mode of preparation
shows, insoluble in cold water, nevertheless a lengthened so-
journ in contact with that liquid brings about slow decompo-
sition ; a little free sulphuric acid prevents this change; hence
in preparing the substance, the necessity of avoiding pro-
longed washing, even with cold water, as the salt begins to
change and grow red as soon as the free acid has been re-
moved. With boiling water the change is immediate; the
substance assumes the colour of rust, and peroxide of iron is
dissolved out. Alkalies decompose it instantly, oxide of iron,
retaining the crystalline appearance of the new body itself is
separated, and the solution after filtration is found to contain
abundance of sulphuric acid. Carbonate of potash with the
aid of heat disengages ammonia; the oxide of iron is not in
this case separated, but remains in solution, communicating
to the alkali a deep red colour ; the addition of water, how-
ever, causes the deposition of the oxide. These characters
suffice to point out the general nature of the substance under
examination.

A portion carefully dried in vacuo was next subjected to
analysis : —

20 grs. dissolved in hot hydrochloric acid and precipitated
by ammonia gave 6 grs. of oxide of iron, and the filtered so-
lution, evaporated to dryness and ignited with the usual pre-
cautions, afforded 2*9 grs. of sulphate of potash, equivalent to
l-58 grs. of potash.

20 grs. of the substance, dissolved in hydrochloric acid and
precipitated by chloride of barium, gave 34--4- grs. of ignited
sulphate = 11*8 grs. of sulphuric acid.

20 grs. of the substance, digested with ammonia and filtered,

upon Fcrrocyanide of Potassium. 23

gave of oxide of iron 5*9 grs. ; the solution by precipitation
with baryta afforded 34-2 grs. of sulphate = 1 1*74? grs. of sul-
phuric acid.

100 parts will therefore contain, if the ammonia be taken
by difference, —

Sulphuric acid . . . 590 58*7

Peroxide of iron . . . 30-0 29*5

Potash 7*9

Oxide of ammonium . 3*1

100-0

A separate specimen, the result of another operation, gave
numbers closely coinciding with the above.

It will be seen that the relation of the sulphuric acid to the
oxide of iron is almost exactly that which exists in common
iron-alum ; the formula

2(Fe303>SS03)+NK06SOd3

gives, reckoned to 100 parts, —

Sulphuric acid .... 58*0
Peroxide of iron . . . 28*8

Potash 8*5

Oxide of ammonium . . 4*7

lOO'O

Taking into account the impossibility of completely wash-
ing the crystals without causing decomposition, a comparison
of the calculated and found results will perhaps be deemed
satisfactory.

This anhydrous iron-alum is apparently the type of a num-
ber of crystalline anhydrous sulphates which may be formed
under similar circumstances. For example, when green vitriol
in powder is boiled with strong sulphuric acid it is dissolved,
sulphurous acid is disengaged, the protoxide of iron passing
to peroxide, which, as fast as it is formed, falls down in com-
bination with the acid as a crystalline pinkish-white powder.
Anhydrous sulphates of copper and nickel may be obtained
by a similar process ; also the double sulphate of nickel and
potash. The copper salt has a beautiful lilac colour ; that of
nickel is bright yellow. All these compounds are, however,
changed by contact with water; the persulphate of iron is the
most stable, but even that ends by dissolving in great part.

There is no difficulty in explaining the decomposition un-
dergone by the ferrocyanide of potassium under the influence
of the acid, and its conversion into the products observed.

1 equivalent of ferrocyanide of potassium and 9 equivalents
of water contain the elements of 6 equivalents of carbonic

24- Mr. S. Tebay's Demonstration of the Rule of Descartes.

oxide, 3 equivalents of ammonia, 2 equivalents of potash, and
1 equivalent of protoxide of iron.

r 6 eq. carbon. 6 eq. carbonic oxide.

1 eq. ferrocyanide potassium = \ a " "S?"'

9* eq. water,

2

»

potassium.

2eq.

potash.

1

)>

iron.

1 eq.

protox. iron

8

»

oxygen.

a

5)

oxygen.

i

»

oxygen.

y

»

hydrogen.

3eq.

ammonia.

At a subsequent period, when the evolution of carbonic
oxide ceases and the temperature rises very high, the iron be-
comes peroxidized at the expense of a portion of the acid,
sulphurous acid is emitted, and the iron-alum gradually
formed, the excess of alkaline sulphates remaining in solution.

In conclusion, it may be worth while calling the attention
of those whom it may concern to the foregoing experiments,
as furnishing an extremely easy and ceconomical method of
preparing carbonic oxide for purposes of research or demon-
stration. A single half-ounce of the yellow salt treated with
some oil of vitriol in a common Florence flask fitted with a
perforated cork and conducting tube, gives more than 300
cubic inches of gas, which has all the marks of the most per-
fect purity : it does not in the least affect lime-water, and be-
comes entirely converted into carbonic acid by explosion with
half its volume of oxygen. The gas given off during the whole
of the reaction is equally pure, except quite at the end of the
operation, when, as before noticed, a little sulphurous acid
appears.

V. Demonstration of the Rule of Descartes.
By Mr. Septimus Tebay of Preston.

To the Editors of the Philosophical Magazine and Journal.

Gentlemen,
f TAKE the liberty of sending you the following simple
method which recently occurred to me of demonstrating
the rule of Descartes.

Let x = v be any equation, and Xp X2, X3, &c. the first,
second and third, &c. limiting polynomials derived from X.
Let the roots of the equations X = 0, Xj = 0, X2 = 0, &c.,
written in descending order, be represented by av ff2, a3 . . .,
&j, &2, bs . . ., c,, c2, c3 . . ., &c. respectively, these numbers
being known to arrange themselves as follows: —

* Probably G eq. from the oil of vitriol, the acid of which has combined
with the ammonia, potash and oxide of iron, and 3 eq. being the water of
crystallization of the salt.

On the Notations of the Calculus. 25

1 <2 i • • •

bv b, b , . . .

Let X and X^ , , be any two consecutive limiting poly-
nomials ; then, since X and X , , have like and contrary

signs immediately before and after the passage of a root of
the equation X =0 (Young on Equations, art. 76), it is

manifest, by inspecting the above arrangement of the roots,
that one variation, and only one, will be introduced on the
passage of each root of the equation X = 0 ; the value of x
being supposed to continually decrease from the greatest root
downwards. Now, since all the positive roots are comprised
between 0 and oo , it follows, from what is proved above, that
the number of variations arising from making * = 0 will ex-
hibit the number of positive roots in the equation ; which va-
riations, it is manifest, are the same, both in number and order,
as those of the original equation.

It is proved in exactly the same manner as above, the value
of x being supposed to increase from the least root upwards,
that no equation can have a greater number of negative roots
than permanencies, or successive repetitions of the same

si£n*

Cor. — It is also plain that, if any two numbers be substi-
tuted for x in the functions X, Xv X2, X3, &c, the difference
between the number of variations, in the signs of the results
of these substitutions, will express exactly the number of roots
comprised between these two numbers.

Yours, &c,
Preston, November 5, 1843. SEPTIMUS Tebay.

VI. Observations on the Notations employed in the Differential

and Integral Calculus. By J. J.*
HPHE differential and integral calculus are applied to nearly
"*• the whole circle of the physical sciences ; scarcely any
treatise on mechanics, optics, astronomy, &c. can be read so
as to be understood without a thorough knowledge of these
extensively useful adjuncts, or at all events without a pretty
close acquaintance with them. It is clearly expedient then
that sciences so generally applied and so constantly occurring
should be kept as simple as possible. The symbols employed
should be as free as they can be from ambiguity, at the same
* Communicated by the Author.

26 Observations on the Notations employed in

time, there should be nothing cabalistic or mystifying about
them. The sciences are nearly universal in their application,
so likewise should be their notation ; and to this end, there
should be a sort of unity about it which would at once iden-
tify it ; so that when a reader opens a scientific treatise he may
know at a glance what calculus is adopted in its demonstra-
tions. He can then begin to read it, but obviously this can-
not be done, if he have been accustomed to one kind of nota-
tion and a totally different one be used in the book: he must
in the first place learn his letters, and if no explanation be
give?i, it may require much time and trouble to bring him ac-
quainted with an old friend disguised in a new dress : he may
have learned Greek and be competent to read that language;
but he may not be able to read the same thing in Hebrew
characters. Clearly, if one kind of symbolical language ex-
presses either of the sciences named more accurately or more
logically than another, that language ought to be generally
adopted, and no other used : such language ought to make its
appearance in evei*y treatise having any pretensions to ele-
gance, and all others be made over for the exclusive employ-
ment of scientific charlatans.

Could writers on the differential and integral calculus agree
upon the point, as to which is the most accurate mode of ex-
pressing the various processes to which they are applied, and
use no other, and would the authors of other scientific works
adopt only the language thus set apart, they would very much
indeed simplify those important sciences, as well as their ap-
plications : they would save their young readers a great deal
of useless trouble: they would also, by giving a oneness and
a generality to the symbols employed, remove from those sci-
ences that shifting, or as some term it hocus pocus sort of
character, to which their appearing now in one form and then
in another certainly entitles them.

Moreover, if one has learned to read a mathematical process
in one symbolical language, it would be difficult to prove how
it adds a particle to his knowledge to be able to read it in an-
other; and therefore the timeandthe trouble that it costs him in
learning to read the process in its new dress is time lost and
labour thrown away. It is supposed that this position will not
be disputed by the advocates of either notation, and if this
be the case, it surely behoves men of competent authority to
consider the subject with the view of rescuing it from such a
stigma ; it is hoped that they will endeavour to prevent the
votaries of science from having their time thus uselessly
wasted ; from being needlessly puzzled by different notations
or bewildered by a mixture: to realize this hope, by calling

the Differential and Integral Calculus. 27

due attention to the matter, is the object of the preceding and
subsequent remarks.

Up to a recent period the fluxional notation was commonly
used by English mathematicians. Mr. Woodhouse assigned
reasons for the adoption of the differential instead of the flux-
ional notation in the preface to his Principles of Analytical
Calculation, published in 1803; he employed the differential
method in an elaborate paper published in the Philosophical
Transactions in the next year : previously he had used the
fluxional notation. The English translation of Lacroix was
published in 1816; the differential notation first occurred in
the Cambridge Problems in 1817. I believe its first appear-
ance in any English mathematical periodical was in the second
volume of the Mathematical Repository, in a solution by Mr.
Ivory.

In the translation of Lacroix's Differential and Integral

Calculus just named, it was laid down that if u be a function

d u
of x and u = ax3, then d u = 3 a? d x, and -=— = 3a^2; the

first expression was termed the " differential" of the equation,
the latter was called its " differential coefficient."

I believe this notation has generally been since used by
writers on the differential calculus, both in England and else-
where ; another mode of differentiating, however, has been par-
tially adopted at Cambridge, or perhaps it may be more ac-
curately termed a substitute for differentiating ; it has been
called " the calculus of differential coefficients:" instead of

writing -^ — , for the differential coefficient as above, they
° dx

write dxu : if u and k be functions of a-, they write
dj, (uz) = u dj. z + z dm u'

d u
Similarly, dx (uz) = uz (z — f- log, u dxz).

The radius of curvature is thus expressed : —

'• = --s^{1+(^)2}f-

The equations of motion are thus written : —
dtx = velocity parallel to x.
dty = velocity parallel to^.
dtz = velocity parallel to z.
d?x= X d?y =Yd?z= Z.
It is well known that these expressions are usually written,
d x d2 x -

Perhaps Mr. Jarrett's paper on algebraic notation in the third

28 Observations on the Notations employed in

volume of the Cambridge Transactions, printed in 1827, con-
tained the first specimen of the index subscript-notation, though
he says Prony and others had previously employed it; the
subscript notation, or the calculus of differential coefficients,
has found its way into some treatises on mathematical subjects.
It is supposed the above examples will be sufficient to indicate
the difference between the subscript notation and that more
generally used ; but in order to become a proper judge of the
difficulty in reading a book written in the new notation, after
one has been accustomed to the common one, the reader must
go through the task himself; and his qualification to give an
opinion will be all the better, if he have to commence with
finding out what the new notation really means.

The notation of Lacroix (that is the notation employed by
him) has been so generally used in mathematical works du-
ring many years, that some strong reason ought to be given for
introducing another ; on this head, however, I have met with
only one advocate, namely, the author of a small work entitled
" On the Notation of the Differential Calculus." The work
is said to be scarce ; my copy has no title-page, but the book
was printed by Metcalf, Cambridge, some time ago. The
author is understood to be a very distinguished member of
the University ; the reader should refer to the book for prac-
tical illustrations and for the full scope of the writer's object;
only some extracts, strictly bearing upon the point under
consideration, can be taken on the present occasion.

Art. 32. The author says, " We must observe that since
d u is obtained from u by performing upon it some operation
with regard to .r, of which it is a function, it is necessary
when u is a function of several independent variables x, y, z,
... to know with regard to which of them the operation d is
to be performed, for the results may be very different accord-
ing as d is performed with regard to the one or the other.
And herein the notation of differentials is defective, for when
we meet with the expression d u it is impossible to know what
it represents. We know, indeed, that an operation of a cer-
tain kind is to be performed on u in respect to some quantity
of which u is a function, but which is that quantity it is im-
possible to tell. Hence arises all that confusion and obscurity
from which very few, if any, treatises on differentials are free ;
and in this respect also it is very much inferior to the cal-
culus of differential coefficients, which is remarkable for its
perspicuity."

Art. 4-2. " Whenever u is a function of one independent
variable, the differential coefficients may be represented by

„ . du d?u d3 u
the fractions -^ , ^, j&

the Differential and Integral Calculus. 29

" But if u be a function of two independent variables x and
y, then, because d u — dxudx + dyu dy>

. . du j dy

we have dxu = -3 — — d«u ~-.

x dx y dx'

from which it appears that the differential coefficient dx u can

no longer be represented by the fraction -? — . Hence the

only notation which is inconsistent with itself, and consequently

erroneous in principle, is precisely that which is most used in

this University, viz. the representing differential coefficients by

- . du d* u
fractions-^ — , -=— ^

d x dx1

" This ought to be a sufficient reason for rejecting it and
endeavouring to invent another which shall at least be con-
sistent with itself. *********

" The ridiculous subterfuges to which writers have been

1. ., r du d?u ,. „

driven by the use 01 -z — , -j- % ...render it a matter of won-

der that that notation has not long ago been banished from
every mathematical treatise."

The writer concludes his work by giving the following ex-
amples of the confusion arising from the common, which he
terms inconsistent notation.

" At page 175 of the Cambridge translation of Lacroix's
Differential and Integral Calculus, we have these two equa-
tions :

du du dz i- , du du dz

dx dz dx dy dz ' dy

on which the author remarks, * the d z of the first equation
must not be confounded with the dz of the second.' Now we
ask, what is there to distinguish dz in the one from dz in
the other ? Nothing. In fact, this remark alone ought to have
been sufficient to demonstrate the necessity of an improve-
ment in the notation. A little below in the same page, we
find the two following explanatory equations :

7 d* j j 7 dz ,

dz — -j— . d x3 and d z = -z— . d y,
d so it y

which we hold to be utterly unintelligible, though they are
given by way of explaining the mystery of their predecessors
above.

" We shall take our next example from a book, the title
of which it is not necessary to mention.

11 ' z being a function of x and y, two independent quantities,

30 Observation^ on the Notations employed in

the following equation is said to express the connexion be-

dz . dz
tween -=— and —. — ,
dx ay

dz dz dz dy .

dx dx dy ' dx **

from which we should naturally conclude that

dz dy

0 = . .

dy d x

'* Now we ask, what connexion does this establish between

-j — and — j— ? Certainly none. In order, however, to ex-

plain how equation (1.) does represent such a connexion, we

are told that — j— - on the left-hand side of the equation does

d z
not mean the same as -= — on the right-hand side;' an ex-
d x

planation not likely to be very satisfactory to a learner."

The above are the strongest reasons, indeed the only rea-
sons, that I have seen advanced for adopting the new notation.
I have made these extracts, in order to set the writer's most
cogent arguments before the reader ; still, I would advise him
to peruse the book and form his own judgement.

With regard to the above quotations, I wish briefly to re-
mark, that it seems to me the reference to Lacroix is not suf-
ficiently explicit to do justice to that work. It should be ob-
served that the two differential equations taken from that work
belong to two sections of the curve surface, the equation of
which is u = 0; and " the dz of the first equation must not
be confounded with that of the second, for they are both only
'partial differentials, as has been remarked in No. 120."

I do not pretend to determine the point, but I am impressed
with the notion that a careful perusal of Arts. 120 and 127
in Lacroix, upon which the equations cited depend, will clear
up the mystic appearance which they bear in the pamphlet.

With respect to the equations d z = —r- .dx and dz = -r .dy,

CI 3C C'T/

said to be given in Lacroix by way of explaining the mystery,

this is what Lacroix really does say : —

" When we have dz = pdx, dz is the differential of the

ordinate of the section parallel to the plane of x and z : and

similarly, dz = qdy is that of the ordinate of the section

d z d z

parallel to the plane of y and z;" here p = -^- and q = -j- :

I am unable to perceive that these equations were intended

the Differential and Integral Calculus. 31

to clear up the mystery ascribed to the equations first men-
tioned. Similar equations to the sections parallel to the planes
zx and z y have been given in Higman's Syllabus, and in
other works : perhaps the geometric signification of the equa-
tions cited ought not to be overlooked in criticising them.
Whether the author, the title of whose book is not mentioned,

himself clears up the apparent paradox that -~ on the left-

dz
hand side of the equation does not mean the same as — — on

CI X

the right side," does not appear. I do not know that I have
his book, and therefore shall leave the author to take care of
himself.

Perhaps it is impossible fully to illustrate the subject en-
tirely free from paradox : thus the writer of the pamphlet on
page 24, says, " the reader must keep in mind, that though x
appears in the expression dx, yet dx is entirely independent
of x" &c. : if d x have nothing to do with x, the quantity, or
whatever x denotes, must have been altogether annihilated,
or completely changed, in becoming dx, and in that case x
in the latter expression ought to have been some other symbol,
to prevent what Berkeley calls njallacia suppositions, or, " a
shifting of the hypothesis"

The writer of the pamphlet in Art. 26, and Professor Miller,
(Differential Calculus, Art. 3), state the operations which dx
denotes when affixed to a function of x; there is, or at least
I fancy there is, a material disparity in their statements ; the
reader can if he please turn to the works and judge for him-
self; my object for naming the circumstance is, because one
of the books was written apparently to recommend the new
notation, and the other is the only elementary treatise that I
know in which it is used.

Having cited the above reasons in favour of the dx notation,
I will now quote two opinions on the other side of the ques-
tion. Mr. W. S. B. Woolhouse, in a very valuable disquisi-
tion on the fundamental principles of the Differential and In-
tegral Calculus, published in the Appendices to the Gentle-
man's Diary for 1835 and 1836, says, " Before closing this
paper I cannot refrain from adding a remark on a new plan
of differential notation that has lately been introduced, and
to a considerable extent adopted at Cambridge. I allude to

(1- ij ci u

the substitution of dx y for —+- , d/y for -y-^, and others of a

similar kind, which possess no recommendation whatever ex-
cept it be that of novelty : and I feel convinced that this change
is suited only to such persons as are satisfied with mere hocus

32 Observations on the Notations employed in

pocus operations on optical symbols without any regard to the
mental images they are designed to represent. In the higher
branches of analysis this new-fangled notation will defy the
presence of anything like distinct ideas: for instance, an ele-
mental parallelopiped dxdy dz is reduced to the confused and
incomprehensible form dxydxz dx?. It is the duty of every
mathematician to make known his opinion concerning it."

Mr. Woolhouse's attainments are such, that his opinion
upon this, or upon any other mathematical subject, is cer-
tainly deserving of respect.

A writer in the Northumbrian Mirror, new series, p. 89,
says, " We cannot conclude without noticing the clumsy dif-
ferential notation which has recently captivated the publishers
of mathematical works at Cambridge; it offends against sim-
plicity, symmetry and clearness; it is a meretricious show of
conciseness, and an innovation that every lover of simplicity,
brevity and neatness, should repudiate.

" In the differential coefficients of two or more varieties the
expression is, of necessity, so overloaded with those little ugly
off-shoots growing out of the side and stem that the body of
the tree is almost hidden from the view."

I have made this quotation to show the writer's opinion,
I certainly do not see that a little x deserves to be called ugly
any more than a great one, but the phraseology is the writer's;
however, it will be observed that the opinions on each side
are made pretty strong.

The integral calculus is the reverse of the differential ;

integration is commonly denoted by the symbol f : thus,

xd.v t /» xdx ,—-

d. V a* + x* = ,-<n—* and A/T^— 'a' = V «2 + x*
Va2-far J vaz+xl

In the suffix notation for integrals the sign of integration is
fx\ in this case only the differential coefficients are employed :
if the dx notation be employed at the same time, then/^ is the
symbol of an operation precisely the reverse of dx ; thus —

dx . V a2 + x2

«s

V a2 + x*

The suffix notation for integrals is found in many of the
mathematical works at Cambridge; for instance, Hymer's
Integral Calculus and Differential Equations, Murphy on
Electricity, Earnshaw's Works, Airy's Tracts, &c.

The authors just mentioned are an honour to one of the
first universities in the world ; they are stars of the first mag-

the Differential and Integral Calculus. 33

nitude in that firmament of science. Ever}' one must feel
that a notation employed by such authors must have some
peculiar advantages to recommend it ; still I believe neither
of these celebrated writers has given any reason for adopting
the suffix notation in preference to the common one. I wish
they had, but as the matter stands I can only adduce their
names in support of the fm mode. On the other hand I wish
to cite the reasons of two justly esteemed authors for employing
the old notation.

Mr. Pratt, in the preface to his ' Principles of Mathematical
Philosophy,' ed. 1835, says, " The prevailing argument with
me for using the old differential and integral notation is the
excellence of Fourier's notation for definite integrals. I much
prefer that to any other that I have seen, and this naturally
led me back to the old form of differentials and integrals.
In case any of my readers are not acquainted with Fourier's

notation, I now give it: / udx represents the integral of
»/ a

the differential coefficient u, or of the differential udx, with

respect to x taken between the limiting values a and b of x.

In successive integrations the order of arrangement of the

integrals is the same as that of the differentials : thus

I I P dpdco represents the double integral of P with

respect to /a. and w, the limits of [x being —1 and 1, and the
limits of :« being 0 and 2?r."

Mr. Gregory, in the preface to his ' Examples of the
Differential and Integral Calculus,' thus expresses himself: —
" I have adhered throughout to the notation of Leibnitz in
preference to that which has been of late revived and partially
adopted in this University. Of the differential notation I need
say nothing here, as it appears to be abandoned as an exclusive
system by those who introduced it ; but as the suffix notation
for integrals has been sanctioned by those whose names are
of high authority, I may state briefly some of my reasons for
differing from them.

" In the first place, on considering the subject, I could find
no arguments against the use of the notation for differentials,
which did not apply with even greater force against that for
integrals; indeed, although there may be some cases in which
the use of the former is advantageous, I know of none in
which the latter does not appear to me to be inconvenient.

" In the next place, I fully agree with Professor De Morgan
in an unwillingness to lose sight of the analogy to summation
which is implied in the old notation : and if it were at any

Phil. Mae. S. 3. Vol. 24. No. 156. Jan. 1844. D

34- Observations on the Notations employed in

time necessary to consider integration merely as the inverse of
differentiation, I should prefer such a symbol as d~\ which
expresses the required idea better thanyj,. But what I look
on as a fatal objection to the suffix integral notation is, that,
like the corresponding one for differentials, it is not applica-
ble to all cases. Of this any one may satisfy himself by at-
tempting to use it in transforming a multiple integral from
one system of independent variables to another, a problem
which is of frequent occurrence, but which I have not seen
solved analytically in any work in which the suffix notation is
employed ; so long, therefore, as the old notation adapts itself
to all cases in which it is required, while that which is pro-
posed is not so accommodating, there appears to me no doubt
which is to be preferred."

Mr. Jarrett, in the paper before referred to, recommended
Fourier's notation ; every one who habituates himself to its
use will, I think, admit that it is admirably adapted to effect
its purpose.

In the commencement of these remarks I gave it as my
opinion that new symbolic language in a scientific treatise
uselessly puzzles the reader and occupies his time without in-
creasing his knowledge; it has been, and will be, my object to
make converts to this notion. Some of the writers above-
named adopt the suffix notation both in differentials and in-
tegrals, others only the suffix for integrals : must not even this
variety be afi incumbrance to a student, and for that reason
ought it not to be exploded ?

Airy, in the commencement of his tracts, says, Ci By the no-
tation of fj cos n . 9 .0, ft cos n 9 . cos m 9 + D, &c, we mean

what are usually written/ cos n 9 .©^9,/cos w9. cos m 9 -f- D d 9,
&c, they are the quantities whose differential coefficients with
respect to 9 are cos n 9 . ©, cos n 9 cos m 9 + D, &c."

To a reader who is unaccustomed to the notation, and who
may perhaps here meet with it for the first time, this explana-
tion is exceedingly useful as a key, it sets him a-going.

In some other books, however, in which the dx andjl nota-
tions are used, not one word by way of definition is said : the
reader has to find out the meaning of a new symbolic lan-
guage used in investigating intricate subjects as he best may :
it seems to be taken for granted, that because the writer knows
the meaning of the hieroglyphics, the reader must compre-
hend them by sheer intuition.

At college, where lectures are constantly given, such diffi-
culties may be well explained viva voce. But the writers of
mathematical works at Cambridge should bear in mind that

the Differential and Integral Calculus. 35

they advertise their books for sale ; the celebrity that so justly
attaches to the University and its members induces lovers of
science who are at a distance from theUniversity, and who are
not acquainted with its advantages, to purchase their works;
they cannot attend the lecture-room, nor is a private tutor at
hand ; the explanation, therefore, that a Cambridge man can
obtain on the spot should form part of the work ; without it,
the book at first appears to be a mathematical enigma, the so-
lution of which wastes the student's time without at all adding
to his knowledge. It is considered very prudent and discreet
in men who have nothing to say, to say nothing, but this is
not the case with the Cambridge authors to whom I allude.
They are quite capable of writing to the purpose, and might
in few words clearly explain a difficulty; in my opinion their
doing so would double the value of their labours, and trebly
enhance their utility; besides, it is only a matter of common
justice to their general readers.

It seems to have become the fashion with many writers to
eschew all introductory or explanatory matter: the reader,
without preamble or preface, is at once pitched into the midst
of a difficult subject entirely in a new dress, and he may make
progress if he can. Works thus written under the notion that
readers intuitively know everything without being told any-
thing, may have more matter compressed into them, but their
authors lock it up and keep the key. To explain myself more
clearly, I will give an example : let any one who knows nothing
of the suffix notation, but who can read, for instance, a treatise
on dynamics in the old, take a treatise on that subject written
in the suffix language, containing no explanation whatever ;
let him move on as fast as he can, and tell me how he likes it.

If the reader has never met with a sudden change from one
notation to another, he may find a specimen in the treatise on
Mechanics in the Encyclopaedia Metropolitana : up to Art. 56,
the differential and integral calculus are employed; subse-
quently the ftuxional: thus within a few lines in writing on pre-
cisely the same subject, the symbols and language are com-
pletely changed. The author of the treatise referred to is
deserving of great respect, but I wish he had taken the trouble
to write the article all in the same language. By way of
parenthesis it may be observed that the expense of these books
is considerable, and judging from their authors' celebrity,
their purchasers have a right to expect the articles to be of a
high order, and not mere scraps indifferently cooked and sent
into the world scarce half-made up; however, many of the
treatises are worthy of their authors, and are a credit to the
seat of learning from which they emanate.

D2

36 Observations on the Notations employed in

It has been before remarked, that a new notation is very
likely to arrest the progress of an uninitiated reader. I
will mention an instance : I some time ago had the good
fortune to fall in with an ingenious mechanic at Penzance,
who has been for several years in the habit of answering many
and sometimes most of the mathematical questions proposed
in the Diaries, &c. ; he told me that he had taught himself
the fluxional calculus, and that by reading the Diaries and
other publications of that description, he had learned to read
and to use the differential mode ; but having never met with
any explanation of the suffix notation, he could not at all un-
derstand it, nor had he been able with all his application to
read a solution written in that language so as to comprehend
the steps in the demonstration ; it had baffled all his efforts,
and he had given up the attempt to find out its meaning.

I for one sincerely respect the votaries of science, even when
education, leisure, fortune, and every concomitant tend to
place them in the most favourable position. No one values
more highly than I do the labours of professors, &c, whose
very calling, the sole business of their life, is science; whose
minds are very often kept on the stretch as a mere matter of
bread and cheese; but if men like these are entitled to esteem
for their mental endowments — and I trust they always will be —
is not the man deserving of it who, after his daily manual toil
of a laborious description, devotes his hours to science and,
notwithstanding every disheartening difficulty, works his way
up to her most secluded walks? If this be so, should not
men eminent by talent as well as by position be careful to
throw no impediments in the rugged paths of such sons of
genius.

At all events, I think they should ; but it is possible that
I may have formed a hasty or a partial judgement upon the
subject, for I well know many of the difficulties attending such
a course, and I readily admit that I have had the case above-
named in my mind's eye in writing the above remarks ; whether
1 have been skilfully keeping to the point so as to effect my pur-
pose or not, is a question not for me to decide : I am quite
sure that each and all of the authors that I have mentioned
would much more willingly assist such devoted disciples of
science as the very remarkable one to whom I have alluded,
and indeed all others, than place the least obstruction in
their arduous paths.

Many of the most esteemed mathematical authors of the
day are correspondents or readers of this publication : the
object of this paper has been to bring to their notice the loss
of time which attends their using new notations in scientific

the Differential and Integral Calculus. 37

treatises without any explanation, and also the uselessness, as
I think, of adopting different notations to effect the same
purpose. Either the common, the suffix, or some other is
the best adapted for general use ; which ought to be constituted
and considered the standard notation, I want the opinion of
your readers to settle : to elicit this, I have adduced the pith
of what has been written in favour of and against the suffix
mode, so that a judgement may be formed with as little
trouble as possible : I have endeavoured to do my part as
impartially as I could. I have aimed to state the case as
fairly as I could in hopes to obtain an impartial judgement
from competent authority. Very likely I may have evinced a
little leaning, for I do not like the suffix notation, but I trust
I have said nothing distasteful to its distinguished advocates :
I am willing to pay homage to their splendid achievements
in science, but whilst I heartily respect their attainments,
I have some misgivings as to their orthodoxy respecting the
subject that has been discussed.

It may save time and trouble if I beg to be considered as
the voluntary, though feeble advocate of such votaries of
science as the one referred to above : as far as I am personally
concerned, all writers may go on their own way rejoicing; what
they may do, or may not do, will not affect me in the least :
on my own account I have no favours to ask. I trust, there-
fore, in dealing with the subject that my mode of advocacy
will be entirely overlooked.

Mr. Gregory says the dx notation is losing ground : if it
be not defunct, I trust it will soon become so: no suffix nota-
tion appears in the last Cambridge Problems : this gives some
hopes. I think there will be a unanimity in the opinion that
the fountain head of mathematical science should be kept
clear, that its streams should enlighten as they proceed and
not darken and mystify. Those who are placed at the source
would in my opinion do well to ponder on the influence they
have on the scientific world, to see how much it behoves them
to throw a light upon all the subjects they handle, but espe-
cially to refrain from making them repulsive by clothing them
with darkness.

Should the preceding desultory remarks educe opinions
which may settle a point that now appears to be doubtful, or
should they have the least tendency to fix the adoption of one
notation, and thus to simplify the science named at the com-
mencement, my aims will have been fully accomplished.

[ 38 ]

VII. Note on the Experiments of Moser. {Extract from the
Giornale Toscano di Scienze Mediche, Fisiche, $r.)*

THE experimentsf of Moser, of which we have cited an
extract made by Mr. Plantamour {Bill. Univ., April
1843, p. 370), are such as to excite the curiosity and interest
of the learned, by their singularity and by the kind of mystery
in which their explanation is still involved. We think, never-
theless, that before we have recourse to new and occult forces
or to new properties of forces generally admitted, it is right to
endeavour to account for them by explaining them by means
of forces, the laws and nature of which we are already ac-
quainted with. The experiments appear to us somewhat con-
nected with those which Prevost, Carradori and Lehot made
several years ago on the adhesion between liquid drops and
the polished surfaces of solids, a subject which has lately en-
gaged the attention of Dutrochet. The ignorance in which
we still remain of the laws which govern these phaenomena
can alone lead us to comprehend how so skilful an observer
as M. Dutrochet can have been induced to imagine a new
force which he calls epipolic, or the force of superficies. The
following is one of the principal conclusions to which Moser
has been led by his experiments : —

" The condensation of vapours on the plates produces a
modification upon their superficies, which is indicated by a
difference in the successive condensation of the vapours which
adhere to them, or which alter them chemically."

The simplest of the experiments which lead to this result
may be made by breathing upon one of Daguerre's plates, or
on a plate of steel or glass, or on the surface of a layer of mer-
cury after having covered this surface with a diaphragm having
apertures in it. In this way the vapour condenses on some
points and not on others; these latter evidently are the por-
tions of the surface covered by the diaphragm. When this is
taken away all disappears after a few seconds; but it is only
requisite to breathe again in order to witness the reappearance
of a figure which represents the diaphragm with all its open
spaces. If the manner in which the condensed vapour disap-
pears from the different points of the surface be attended to,
we shall see that the parts of the diaphragm which are not co-
vered, and where the vapour had been condensed at first, are
those from which it soonest disappears.

On examining the plate which was breathed on a second

* From the Bibliothvque Universelle for August 1843; vol. xlvi. p. 374.
•f- For Moser's account of these experiments see Taylor's Scientific Me-
moirs, vol. iii. p. 422, et seq.

Note on the Experiments of Moser. 39

time, it will also be seen, that the portions which had been
covered by the diaphragm condense a more opake layer of
vapour and apparently thicker than that which covers the
other portions on which the vapour was condensed in the first
experiment. It does not appear difficult to explain this fact
by the general principles of adhesion. A drop of water placed
on a surface of glass or upon any other substance, however
polished it may be, always preserves a more or less globular
form, according to the mass of the drop and the cleanness of
the surface itself. Dutrochet has lately proved, that in order
for a drop of water to spread itself in a thin layer on a glass
plate, it is necessary to give this plate a fresh surface which
has not yet been subjected to the contact of atmospheric air.
Upon every other surface the drop remains globular, and if
the layer of condensed vapour which is obtained by breathing
upon a polished surface be examined with a lens, we see that
this layer is composed of a quantity of infinitely small globules
of water, which differ only by their size from the globules of
water that are obtained in letting fall this liquid on a surface
covered with dust or oil. It is natural to admit that when
some portions of a surface have been covered with these glo-
bules, which by their union form the condensed vapour, they
have preserved, and continue for a long time to preserve, a
thin layer of moisture, a layer of globules smaller than those
which had been formed at the beginning of the condensation.
No physicist is ignorant of the tenacity with which these layers
of water, or rather these veils of moisture, adhere to the sur-
face of solid bodies, and how difficult it is, even with the aid
of heat, to get rid of them entirely.

If, when in the state we have just described, we present to
this surface a fresh vapour to condense, the points which have
preserved a more evident humid veil exert upon the globules
of the fresh vapour which is condensed a force of adhesion
which will be manifested by effects different from those which
will take place on the other points. At the points where the
humid layer will be most conspicuous the adhesion will take
place between two aqueous layers, or at least between an
aqueous layer and some points more covered with water than
the others are. The globular state will then be less developed,
and the liquid will have a tendency to form a smooth layer
rather than globules ; a greater transparency on these parts
will be the result of this, and, by analogy with the property
which water in a globular form possesses when in contact with
hot metals, a quicker evaporation on the points where the
globules are less well formed.

Let us mention another experiment made by M. Moser,

40 Note on the Experiments of Moser.

and which is very easy to repeat. A medal is taken, an en-
graved plate or the print of a seal, and it is tarnished with the
breath ; then, whilst this surface is <hus covered with a layer
of condensed vapour, one of Daguerre's plates is placed upon
it and left there for some instants ; it is then removed, and we
find the print of the medal, of the engraving, or the seal traced
upon the plate by the vapour which is unequally condensed
there.

If the object subjected to the experiment had been covered
with a layer of mercury or of iodine, instead of being tarnished
with the breath, the same result would have been obtained.
In all cases in which the drawing is produced the vapour is
not deposited on the portions which are in intaglio, but this
difference disappears if the two surfaces are left a long time in
contact. It seems natural to admit that the nearest points are
those on which the condensation of the vapour first operates.
When a gold leaf is suspended in a vessel, at the bottom of
which there is some mercury, the leaf begins to grow white
on its under side which is nearest to the surface of the mer-
cury. When once an image is formed on a surface by the
unequal condensation of the vapour, it will be understood, ac-
cording to the principles already explained, how it is rendered
visible by the condensation of fresh vapour.

If the medal, &c. is put in contact with the plate after being
heated, instead of covering it with vapour, the same phaeno-
menon takes place, that is to say, the images reappear. In
this case it may also be admitted, that by heating the medal,
&c. the veil of vapour which covered it has been forced to
disappear; it is the same phaenomenon which must take place
when a plate of metal or of glass is exposed to the direct
action of the solar rays, being covered with a perforated dia-
phragm which has emitted some vapour, the condensation of
which afterwards took place on the points of this diaphragm
in contact with the plate. That being allowed, the results
which have been obtained necessarily come under the cases
quoted. This explanation may be rendered more complete
by means of an experiment easy to execute, and which was
made in our laboratory. When we operate in vacuo, and let
the medals and other objects used in the experiment cool
there, the images by contact, which should become manifest
with the successive condensation of the vapours, are not pro-
duced.

If we also admit (what seems in accordance with our know-
ledge on this point) that all the surfaces of bodies exposed to
the atmosphere are covered with a veil of moisture, — that this
veil must continually increase or diminish in passing from one

Mr. J. Denham Smith on an Acid Oxide of Iron. 41

surface to another, — that even the most solid bodies may be
conceived to emit vapours which after a long space of time may
produce that which their surfaces rapidly produce when they
are covered over with substances which easily evaporate, — we
shall then not be compelled to have recourse to new forces, nor
even to the rays of a latent and invisible light in order to ex-
plain the ingenious experiments of Moser. We are far from
pretending to have given a complete explanation ; we only
proposed to show that they might be explained in entire con-
formity with the fundamental principle of the logic of experi-
mental science: Causas rerum naturalium non plures admitti
debere, quam quae et versa sint et earum phaenomenis expli-
candis sufficiant.
Pisa, March 1843. C. M.

VIII. Note on the Paper published in the Philosophical Maga-
zine for September 1843, " On the Composition of an Acid
Oxide of Iron {Ferric Acid)." By J. Denham Smith, Esq.
To Richard Phillips, Esq., F.R.S. L. and E.3 fyc.
My dear Sir,
T1/"ILL you oblige me by inserting in the Philosophical
Magazine the subjoined correction of errors in the paper
referred to above ? These errors arose partly from the almost
invariable presence of manganese in the oxide of iron (ferri
sesquiox. Pharm. Lond.) employed in my experiments, — an
impurity neither suspected nor guarded against by me, and
which usually occurs in such minute quantities as to render its
detection impracticable by the ordinary tests, — and partly from
the solubility of oxide of iron in potash, under certain condi-
tions, a fact pointed out by M. Chodnew.

The first error occurs in p. 220, where a solution, which
subsequently proved to be permanganate of potash, is described
as a permanent solution of the ferrate of that alkali. The
second and more serious error is that of the announcement of
an oxide of iron possessing acid properties and forming a
combination with potash, affording a green solution with water.
After a careful examination I find this bright emerald green
solution to be manganate of potash, and potash holding ses-
quioxide of iron in solution.

Having, in the paper referred to, satisfied myself that an
oxide of iron did form a salt with potash, and also that the
green salt contained this metal, I was too hastily led to infer
that both these solutions were salts of acid oxides of iron, not
suspecting the existence of manganese in the precipitated oxide
of iron; this impurity probably arises from the iron turnings
generally employed to saturate the excess of acid in the iron

42 Dr. M. Barry on Prof. BischotFs History

liquor of the copperas beds, and thus contaminating the sul-
phate of iron from which the oxide of iron employed by me
was obtained. Yours truly obliged,

Romford, Dec. 18, 1843. J. DENHAM Smith.

IX. Remarks on a Work by Prof. Bischoff of Heidelberg,
entitled " Entisoickelungsgeschichte des Kaninchen-Eies"
(History of the Development of the Ovum of the Rabbit),
1842. By Martin Bahry, M.D., F.R.S.S. L. and E.
HP HE following is the substance of notes written nine months
•*■ since, when I was reading the work of Prof. Bischoff.
Should the editors of the Philosophical Magazine consider
them suitable for insertion in their Journal, I shall feel obliged
by their allowing them to be published there.
19, X mo. (October) 1843. Martin Barry.

Bischoff", Plates I. to VIII. inclusive.— There is certainly
some satisfaction in finding that observations recorded by my-
self two, three, and many of them four years since, in the
Philosophical Transactions*, have led to a repetition of the
same. But it is not very satisfactory to observe the mutilated
form in which my figures are made to reappear. This last
remark is intended to apply more particularly to figures re-
presenting the divisions which the essential portion of the
ovum undergoes in the Fallopian tube.

Professor Bischoff seems to have adopted in part my mode
of obtaining ova (" Second Series," /. c, p. 365). Had he
fully done so, he would not have found it needful to raise the
ovum out of the oviduct with a needle ; a sort of manipulation
that it will not bear. And had he used the ring of putty I
recommended, the ova might have been preserved for days,
weeks, and even months ; instead of requiring to be kept from
drying up by the addition of foreign substances, which not
only diverts the attention of the observer, but completely
changes the appearance of the ova, and admits of their being
examined but for a very short time. The ovum fig. 16, it ap-
pears, had lain in water ! Nothing whatever should be added
to ova from the oviduct; nor is it advisable to make any addi-
tion to those from the uterus that have not attained a consi-
derable size.

Nature is not represented in the figures Bischoff has given
of the so-called " yelk." This substance in the mammiferous
ovum, as I long since showed, corresponds to little more than
the " discus vitellinus " in the ovum of the Bird ; and, like it,

• Researches in Embryology: First Series, Phil. Trans. 1838 j Second
Series, Phil. Trans. 1839; Third Series, Phil. Trans. 1840.

of the Development of the Ovum of the Rabbit. 43

consists of cells : which indeed are represented in two of Bis-
chofPs figures (figs. 8 and 9).

Formation of' the Ovum. — No one on reading p. 19 of Bis-
choff's book would suppose that the formation of the ovum
had ever been described : still less would it be imagined that
the writer was confirming observations recorded four years
before. But I ask the reader to compare in detail BischofF's
figs. 10 to 13 with about twenty of my own in Plate 5. Phil.
Trans. 1838; and more especially BischofF's fig. 10 with my
figs. 2, 3, and 19, in that same plate: a stage being there re-
presented which he actually says (p. 19) I "overlooked"
[Stages still earlier than this will be found represented in a
paper of mine "On the Corpuscles of the Blood," Phil. Trans.
18*1, plate 25. figs. 164—173, and described § 188—195.
It is there stated that the vesicle called by me the ovisac, with
the whole of its contents, arises out of a body having precisely
the same appearance as a mammiferous young blood-disc, —
this blood-disc, as I have shown, being originally elliptical and
not round : the outer part dividing into minuter discs, which,
forming cells, coalesce to produce the membrane of the ovisac.
The germinal vesicle has previously been formed out of the
central portion of the disc]

Misstatements.

Bischqff", p. 14. — What I said regarding the changes in
the germinal spot, was obviously meant to apply to its condi-
tion as preparing for fecundation, and I headed the paragraphs
"preparatory changes in the germinal vesicle and germinal
spot." Yet BischofF makes it appear as if my description had
been intended to apply to the state of the germinal spot as
usually found.

Bischoff p. 4. — I never attempted to show that my "reti-
nacula" were the analogue of the chalazae; but, on the con-
trary, showed that they could not be so regarded. (See my First
Series on Embryology, /. c.f § 92.)

Bkchoff, p. 49. — My observations on the time taken by the
ovum of the Rabbit to pass through the Fallopian tube, are
not correctly stated. A table (my " Third Series," I. c, p. 565)
shows that, 230 ova having been found by me in the tube,
some of them had been met with there as early as the tenth
hour, and others as late as the seventy- second hour post co'i-
tum. — In the same page (p. 565 of my "Third Series") will
be found also the following words : " It will be seen from these
Tables, that ova have been found in the Fallopian tube as
late as 72 hours, and in the uterus as early as 52 hours post
co'itum."

44 Dr. M. Barry on Prof. Bischoff 's History

Bischoff, p. 86. — I never added any chemical reagent to
ova of the size of Bischoff's ovum figs. 29 and 30. He makes
it appear as if the addition of a reagent had been my practice.

Bischoff, p. 10. — Professor Bischoff has no authority what-
ever for stating that I appear to have used for the most part
a magnifying power of 100 diameters. The objects were for
the most part delineated as magnified 100 diameters; but it
surely does not follow that no higher magnifying power was
used in the examination. The powers employed varied, from
less than 100 to 800.

Bischoff, p. 89. — States that Barry has not attempted to ex-
plain the appearance of the ovum in his fig. 119 (my " Second
Series"); which, therefore, and because he (Bischoff) saw
such a condition of the ovum only once, he thinks was an
aborted ovum. — The reader will find whether I failed to ex-
plain this appearance, on referring to my " Second Series" of
Researches, /. c, § 201, which paragraph is entitled "nine-
teenth stage of development — hollow network in the ovum."
This state of the ovum then it appears was seen by Bischoff'
"only once!" (See my figs. 120, 121, 152, for later stages.)

Bischoff, p. 3. — Says that the ovulum is "covered on all
sides by the cells of the membrana granulosa," and that these
cells, being more densely aggregated around the ovulum, form
an opake ring. Yet this, though covering the ovulum " on
all sides," he calls a disc. Had Bischoff obtained a suite of
stages, he would have seen it sharply circumscribed, and per-
fectly spherical in form.

Bischoff, p. 30. — " In this state of things observation needs
to take but one step more, i.e. only to see the spermatic
threads [spermatozoa] penetrate the ovum, or to find them
there : a probability would thus become a certainty." — p. 32.
" But I have never been able to convince myself that one of
these spermatic threads [spermatozoa] was in the interior of
the ovum." Professor Bischoff may now be informed that
this has at last been done (see " Proceedings of the Royal So-
ciety, Dec. 8, 1842"); spermatozoa within the "zona pellu-
cida," i. e. certainly in the interior of the ovum, having been
found by myself, and shown to, and acknowledged by, others,
— among whom was Professor Owen, who, in a note 1 have
received from him, states that he "can confidently attest the
reality of the spermatozoa." [Since the above was written, I
have confirmed my first observation by a second.]

Bischoff, p. 38. — Acknowledges having seen the germinal
spot to appear not quite round, but like a flattened vesicle,
and presenting a "pellucid ring." And though in 1839 he

of the Development of the Ovum of the Rabbit. 45

thought himself enabled to pronounce the disappearance of
the germinal vesicle in Mammals, also, " as a decided fact,"
he now, in 1842, after seeing my papers, acknowledges (p. 39)
that " very probably the nucleus of the germinal vesicle [i. e.
the germinal spot] is the essential part, which first of all ex-
periences the influence of the coitus, namely a mixing with
the seminal fluid." [I had shown the centre of the altered
germinal spot to be the 'point of fecundation.^

Bischqff, p. 56. — " I have certainly several times observed
in the yelk a part more pellucid than the rest, the presence of
which undoubtedly is of great importance." This probably
was not the germinal vesicle, but an early state of the twin
successors of it. (See my figs. 187, 191, 193, in plate 24, Phil.
Trans. 1840.) — I have at this time several ova in a state nearly
resembling these, which have been preserved for many weeks
by means of the putty ring; the entrance of the air having
been further prevented by a cement consisting of gold size
(Lein-oel Firniss) and a little lamp-black.

Bischqff, fig. 1. — What Bischoff describes as cells of the
membrana granulosa, appear to have been cells of the central
part of the retinacula. [The retinacula will be found exceed-
ingly distinct in the Ferret — Mustela Furo ; which animal I
selected when showing these structures to Professor Owen.]

Bischqff] fig. 2. — " Fleckiges Ansehn." The same appear-
ance will be found represented by myself in the Phil. Trans.
1840, plate 24, figs. 188, 189; and the cause producing it is
described in p. 541 of that volume (§ 357).

Bischqff, fig. 6. — The five so-called small yelk-balls appear
to have been cells, that had not undergone that liquefaction
which removed the other cells in the layer of which they had
formed a part.

Bischqff, fig. 16. — Mistakes blood-corpuscles for cells of
the so-called "discus," which, after becoming club-shaped,
he supposes to have returned to their previous form. [The
ovum had lain in water ! p. 54.]

Bischqff, figs. 19, 20. — Mistakes the incipient chorion for a
deposit of albumen.

Bischqff, p. 61. — Says nothing on the subject of a fact to
which I directed particular attention; viz. that, on pressure
being applied, the young chorion becomes elliptical. Is this
to be expected of mere albumen ? [Bischoff had previously
said — Wagner's Physiologie, p. 96 — "most certainly the
ovum receives in the oviduct no new covering ; it receives no
layer of albumen and no i schalenhaut,' like the ovum of the
ovipara."]

Bischqff, fig. 17. — Mistakes solitary cells, not yet liquefied,
for " Nachkommen des Keimfleckes."

46 Dr. M. Barry on Prof. Bischoff's History

Bischqff] p. 87. — After altogether denying the existence of
cells hitherto, — now suddenly admits them.

Bischqffi, fig. 42 G. — " Star-shaped and nucleated cells often
uniting with one another." " The situation and relation of
these cells between the cell-layers forming the animal and ve-
getative laminae, make it possible that they belong to that
which becomes what certainly manifests itself as the vascular
lamina, and that they indicate the commencement of the ves-
sels of the area vasculosa." Compare this figure of Bischoff's
— fig. 42 G, — and the description now quoted, with fig. 132
in my "Second Series" (I.e., 1839), and with the description
I there gave of it, viz. " Fig. 132. A portion of the network
of which the subsequently vascular lamina of the umbilical
vesicle consists" (/. C, p. 379). My figs. 120, 121 and 150
are mentioned in that same paper, as representing the succeed-
ing stages, — fig. 150 being thus described : "Vesicles of the
outer and subsequently vascular lamina of the umbilical ve-
sicle." With these passages before his eyes, and at the same
time comparing my fig. 120 with his fig. 41 g, how could
Professor BischofF coolly say that, since the cells in his fig.
41 g presented precisely such an appearance as that which
Schwann had given of the first development of the vessels in
the Bird's egg, the thought had occurred to Mm ("so gerieth
ich auf den Gedanken") whether at this early period there
might not exist a cell-layer in which the future vascular lamina
should have its origin ! (See his pp. 96, 97.)

BiscJutff] p. 95. — Boasts of being able to demonstrate two
laminae of the "germinal membrane" in the Rabbit's ovum
measuring If" to 2'", and forgets that this had previously
been shown in a rabbit's ovum of less than i'"; and that
("Second Series," I.e. §206, figs. 120, 121 A) the inner
layer, or vascular lamina, as I called it, had been stated to
present a lamina internal to it. In 1839 I remarked (" Second
Series," I.e. § 167), "there is no fixed relation between the
size of the entire ovum, and the degree of development of its
most essential part;" in proof of which I referred to my fig.
1^4, — and the variable period at which villi begin to appear
on the chorion afforded another instance. This irregularity
should be borne in mind. It probably explains how it is that
the same appearance should present itself in an ovum of 3'"
(Bischoff's fig. 42 G), and in one of §■'" (my fig. 120) ; being
incipient also in an ovum of i'" (my figs. 1 19, 132). It should
be recollected that Bischoff did not always find it in his more
advanced ova (p. 97) ; and that, as above stated, I have met
with ova of 2'", apparently not more advanced in reference to
the network, than the ovum in my fig. 119 — which measured
only £'".

of the Development of the Ovum of the Rabbit. 4-7

Bischqffl, figs. 21 to 30. — The germ dividing and subdivi-
ding by means of cells, is coarsely represented as the " zerle-
gung" of what BischofF supposes to be the "yelk." The
original figures will be found in the Phil. Trans, for 1S39
and 1840 ; to which, and more especially to the latter volume,
the reader is referred for an explanation of the process by
which the germ thus reproduces itself, and multiplies its cells;
a view being there given essentially differing from the views
of others regarding "cells," — which latter certainlv could not
have explained the process. It is deserving of notice, that
BischofF, — though he takes some pains to show the inapplica-
bility of the theory of "cells" to the divisions of what he
calls the "yelk," — avoids mentioning my peculiar views on
"cells."

Bischoff; figs. 31, 32, 35, 36, 37.— Having failed to find the
large cell in the mulberry-like body, BischofF also fails to dis-
cern its nucleus, and mistakes the cells lying around this
nucleus, and the cells into which the outer portion of this
nucleus has been resolved, for a heap of yelk-globules, re-
maining over in order to future use.

Bischojffi fig. 39. — The " Fruchthof," represented in an
ovum of I'". I am not surprised that BischofF could describe
and figure this region merely as a spot — the tache cmbryon-
naire of Coste— consisting of nucleated cells in different degrees
of aggregation. At this I am not surprised, for BischofF ac-
knowledges having seen no ova between ±-'" and \V} : and this
he calls " a small hiatus" in his observations. It is added
that the " Fruchthof" (tache embryonnaire) in previously
mentioned ova was not recognised, " but yet perhaps was pre-
sent, and only very difficult to find." At p. 92 it is remarked,
" I will not deny that it [the ' Fruchthof] is to be found in
ova of I'": indeed it may be traceable to the remains of the
yelk-globules, which were not all expended in the formation
of the germinal membrane." BischofF then is not prepared to
deny that the " Fruchthof" or tache embryonnaire may exist
in ova of ~". At p. 91 he confesses having seen no ova be-
tween j'" and I'". This, as already stated, he calls " a small [?]
hiatus" in his observations, which he regrets, because "Barry's
marvellous figures 121 — 126 relate to ova off", £"', and £'""
— i. e. they relate to just that period, concerning which Bis-
chofF confesses he failed to make any observations. On the
states represented in " Barry's marvellous figures " (figs. 121,
&c.) it is added, " Of importance they cannot be, as subse-
quently nothing is found of them." Yet, after examining
larger ova, he admits that "perhaps there is something present
of an explanatory character" in smaller ones. Yes, Professor
BischofF, had that " small [?] hiatus " been filled up, it would

48 Dr. M. Barry's Remarks on a Work by Prof. Bischoff.

have shown the mode of origin of the spot, " Fruchthof," or
tache embryonnaire, — and the supposed "original foundation of
the body of the embryo" ( Bischoff'' s fig. 48) to be merely a
st age in the growth of what had come into existence some time
before: Bischoff would have seen the "primitive trace" of
authors to be an accumulation of the cells, or foundations of
cells, continually arising in what had been a pellucid space,
and marking the locality of the nucleus of the embryonic cell,
— the central pellucid groove or channel (" Primitivrinne") in
Bischoff 's " original foundation of the body of the embryo "
being no other than the elongated pellucid centre of that
nucleus.

Bischoff adopts the views of others, that the germinal mem-
brane "thickens" at a certain part, and that in this thickened
portion the embryo has its origin. What is the cause of this
supposed thickening of a membrane? It is no other than that
continual origin of new cells in the pellucid centre of what had
been the nucleus of the embryonic cell, and the continual re-
production of the cells so arising. As the embryonic cell
exists in the mulberry while the mulberry is in the centre of
the ovum, its nucleus is no part of any membrane. Had in-
vestigators begun with smaller ova, — i. e. at an earlier period,
— and had they left no " small [?] hiatus " in their observa-
tions, they would have found that it is not a previously exist-
ing membrane which gives origin to the embryo, but a previ-
ously existing mulberry-like body, which, by certain changes,
assumes the form of a membrane, in a certain part of which
the development of the already existing embryo proceeds, in
the way I have described — from the nucleus of a cell.

It might appear remarkable that Bischoff should not attach
much importance to the "small [?] hiatus" just referred to,
since in the same page (p. 91) he had only just said that the
changes follow one another with such rapidity that "an accu-
rate understanding is scarcely possible, if all the intermediate
stages have not been observed." But, notwithstanding this
most just remark, a "small [?] hiatus" seems to be no un-
common thing in the observations of Professor Bischoff. Thus
it appears (p. 54) that his "conclusions" respecting figs. 185,
188, 189, 190, 193, 194, 195, 199, 200, &c. in the "Third
Series" of my "Researches in Embryology" (Phil. Trans.
1840), were drawn from an examination of the ova of only
three rabbits (pp. 53, 54); the ova of one of these having lain
in water, and those of another not having been taken out of
the oviduct until "nine hours" (p. 57) "after the rabbit had
been killed." Again, on the subject of what is stated in my
"Third Series" concerning changes following fecundation
before the ovum leaves the ovary, he ventures to pronounce

Mr. G. Salmon on Theorems of Pascal and Brianchon. 49

an opinion from the examination of one dog and one rabbit
(p. 37)*.

Professor BischofFs book affords-a striking instance of the
truth of a remark made by myself long since; — viz. that with-
out a knowledge of the fact that the germinal vesicle returns
to the centre of the ovum, it is not possible to learn the mode,
the period, or the place of origin of the new being; or indeed
to understand the ovum in any of its future phases.

In 1839 a note was added to my " Second Series" while
passing through the press, concerning Bischoff's contributions
to the plates accompanying R. Wagner's ' Physiology,' which
had subsequently come into my hands. My belief was there
stated that, while Bischoff's figures showed him to be in ad-
vance of others in his acquaintance with the mammiferous
ovum, they also showed that he had not obtained a suite of
early stages (" Second Series," I. c.t p. 354-). From the ani-
mus everywhere recognizable in Bischoff's book now under
consideration, it is evident that the opinion expressed in that
note has never been forgiven. What I then said, however,
I am now compelled to repeat, and to extend to Bischoff's
present communication on the ovum of the Rabbit.

There is a word of counsel too, that I am under the neces-
sity of offering Professor Bischoff. When he professes to
communicate what has been done by others whose researches
have preceded his, and yet thinks proper, for some reason,
here and there to pass very lightly over, or altogether to omit,
certain portions of the history, — he should take care that, in
other parts of his book, none of these omitted portions are in-
advertently permitted to creep out.

X. On the Properties of Surfaces of the Second Degree which
correspond to the Theorems (^Pascal and Brianchon on Conic
Sections, By George Salmon, Esq.

To the Editors of the Philosophical Magazine and Journal.

Gentlemen,

[" PERCEIVE that you have inserted in your last volume
■*■ [S. 3. vol. xxiii.] analytical demonstrations of the theorems
of Pascal and Brianchon on the Conic Sections. The two
theorems being connected by the theory of reciprocal polars,
it is sufficient to prove one of them, and for the best analytical

* I sacrificed nearly a score of rabbits for the purpose of determining
the condition in which the ova leave the ovary; and was thus enabled to
show that the period of their discharge from this organ is very frequently
nine or ten hours post co'itum, an observation which Bischoff states to have
been confirmed by his own. (See my " Second Series," /. c., pp. 310, 3] 1.)
Phil. Mag. S.3. Vol. 24. No. 156. Jan. 1844. E

50 Mr. G. Salmon on Theorems of Pascal aud Brianchon.

demonstration of Pascal's I would refer to Gergonne's An
nales, vol. xvii. p. 222.

I venture, however, to offer in addition the following proof
of Brianchon's theorem, because it leads at once to the corre-
sponding property in surfaces of the second degree.

Let S = 0 be the equation of a given conic, L = 0 that of
a right line ; then it is easy to see that S — L2 = 0 is the
equation of a conic touching the given in the two points where
it is met by the line whose equation is L = 0.

Let S — L2 = 0 be the equation of another cone having
also double contact with the given. Subtracting these equa-
tions, we have for the intersection of the last two conies
L2 — L2 = 0. The equations therefore of two chords of in-
tersection are L — Ly = 0, L 4 L/ = 0. These two chords
must pass through the intersectionsofthetwo chords of contact,
since their equations are satisfied by the combined equations
L = 0, Ly = 0.

It would lead me into too much detail to prove that the
form of the equations shows that the four lines form an har-
monic pencil.

Now let a third conic have also double contact with the
given. Its equation will be of the form S — L/y2 = 0. The
equations of its chords of intersection with the other two,
L - L» = 0, L + L„ = 0, L, - L„ = 0, L, + L„ = 0.

Evidently the three equations L — L, = 0, L; — h,, = 0,
L — L7/ = 0 are satisfied for the same point ; also L — Lt = 0,
Ly + Ly/ = 0, L + Lw as 0, and so of the rest. Hence "if
three conies have each double contact with a fourth, their six
chords of intersection with each other pass three by three
through the same points."

Now let each of the three touching conies degenerate into
a pair of right lines, and we have Brianchon's theorem.

Now everything we have said applies almost word for word
to surfaces.

The equation of a given surface of the second degree being
S as 0, that of a plane Jj = 0, another surface touching the
given along this plane will have its equation of the form
S — L2 = 0. A second surface also enveloped by the given
has for its equation S — L/2 = 0. Precisely as before these
two surfaces intersect each other along the planes whose equa-
tions are L — L, =s 0, L -f- L, = 0. Hence " if two surfaces
of the second degree are enveloped by a third they will inter-
sect each other in two plane curves, and the planes of inter-
section pass through the intersection of the planes of contact."
Let a third surface be also enveloped by the surface S; its
equation is of the form S — Ly/2 = 0, and its planes of inter-

Geological Society. 51

section L — Ly/ = 0, L -f L/y = 0, Ly + L,y = 0, L, — L,, = 0.
First, all six planes of intersection pass through the intersec-
tion of the three planes of contact, for their equations are all
satisfied by L = 0, L, = 0, L/; = 0. And as before they pass
three by three through the same lines.

Suppose the enveloping surfaces to be cones, and we have
a theorem corresponding to Brianchon's.

Form the reciprocal theorem and we get the following: —

" Take any three plane sections of a surface of the second
degree ; through any two of them a pair of cones can be drawn.
The six vertices of these cones are in the same plane, and each
set of three on the same right line." They form in fact the
angles of a complete quadrilateral.

How analogous this theorem is to Pascal's, the reader will
perceive more plainly if he form a figure. Mark the six sides
of a hexagon inscribed in a conic ABCDEF, and the three
intersections of opposite sides GHK. Now irmigine the conic
to represent a surface of the second degree, A D, B E, C F,
three plane sections of it, ABGDE, BCHEF, CDKFA,
three cones containing these sections. This theorem asserts
that the three vertices GHK are still on a right line.

M. Poncelet has given this property in his treatise on pro-
jective properties, but I do not think it has been perceived
how analogous it is to the theorem of Pascal. M. Chasles,
for example, has assigned a different theorem as the one cor-
responding to Pascal's. As his theorem however only asserts
that certain lines are generatrices of the same hyperboloid of
one sheet, the analogy can hardly be considered so perfect as
in the present instance.
Trinity College, Dublin, GEORGE SALMON.

October 5, 1843.

XI. Proceedings of Learned Societies.

GEOLOGICAL SOCIETY.

Feb. 22, \ PAPER was read "On some new species of Fossil
1843*. ■**- Chimaeroid Fishes, with remarks on their general affi-
nities," by Sir Philip Grey Egerton, M.P., F.G.S.

The number of described species of Chim3era— soft-boned fishes
of singular forms — is very small, whether existing or extinct. They
were first recognised in a fossil state by Dr. Buckland in 1835.
The original memoir comprised descriptions of four species ; two
others were added by Professor Agassiz. The list was soon after-
wards augmented by two species from the Stonesfield slate, con-
structed by Dr. Buckland from some enigmatical specimens forwarded
by the author under the impression that they had some resemblance
to the subjects he was engaged upon. A ninth species came from

* The President's Annivesary Address, delivered Feb. 17, will be found
in Phil. Mag. S. 3. vol. xxii. p. 51 1.

E2

52 Geological Society: Sir P. Egerton

the Caen oolite. A tenth has heen described by Professor Owen in
his ' Odontography' from specimens in the Hunterian collection, and
Professor Agassiz has named an eleventh in the museum of Lord
Enniskillen, from the gault. Sir P. Egerton, in the present memoir,
doubles the number. With one exception he founds his characters
on the lower jaws of the animals, avoiding the risk of ascribing spe-
cific differences to teeth derived from one and the same species,
varying in form according to their position in the mouth.
The characters of the new species are as follows : — ■

1. C. neglecta. — Maxillary plate, left lower jaw : length 6 lines ;
depth at the symphysis 2 lines ; ditto at the medial angle of the
dental edge 3 lines ; length of the dental edge 3^ lines ; anterior
division of ditto 1| line ; posterior ditto ditto l£ line ; length of the
heel 2^ lines ; exterior convex ; exposed surface slightly furrowed ;
base expanded and vertically striated ; two depressions, the anterior
one broad, the posterior narrow and deep. Stratum, great oolite :
locality, Stonesfield.

2. C. Bucklandi. — Maxillary plate, right lower jaw (imperfect):
length 2 inches 1 line ; depth at the symphysis 1 inch 2 lines ; ditto
at the medial angle of the dental edge 9 lines; length of the dental
edge 1 inch 6 lines ; anterior division of ditto i inch ; posterior ditto
mutilated ; exterior smooth and flat ; inner surface rounded, dimi-
nishing in diameter towards the base ; symphysis oblique and
rounded ; texture dense. Stratum, great oolite : locality, Stonesfield.

3. C. psittacina. — Maxillary plate, right lower jaw: length 8
lines ; depth at the symphysis 4 lines ; ditto at the medial angle of
the dental edge 4 lines ; length of dental edge 4 lines ; anterior
division of ditto 1| line; posterior ditto 1\ lines ; heel 3^ lines ;
exterior flat, marked by horizontal undulating bands on the base,
with a few vertical striae near the heel ; two depressions, broad and
shallow ; anterior outline abruptly curved upwards to the point.
Stratum, great oolite : locality, Stonesfield.

4. C. curvidens. — Maxillary plate, right lower jaw : length 1 inch;
depth at the symphysis 4 lines ; ditto at the medial angle of the
dental edge 5 lines ; dental edge 7 lines ; anterior division of ditto
3 lines ; posterior ditto ditto 4 lines ; heel 3 lines ; exterior convex,
curving rapidly inwards to the symphysis ; exposed portion invested
with a thick lustrous enamelloid coating, 3 lines in depth at the
symphysis; base expanded and closely striated ; one elongated depres-
sion near the heel ; anterior division of the dental edge concave,
posterior ditto straight. Stratum, great oolite : locality, Stonesfield.

5. C.falcata. — Maxillary plate, left lower jaw: length 1 inch;
depth at the symphysis 3^ lines ; ditto at the medial parts of the
dental edge 4 lines ; heel 4 lines ; dental edge 6 lines ; tooth elon-
gated, falcate, the point curved upwards ; base shallow anteriorly,
expanded and traversed by a broad depression near the heel ; ver-
tical striae indistinct ; horizontal bands broad and undulate ; cutting
edge concave, forming a single curve without any medial angle from
the point to the heel. Stratum, great oolite : locality, Stonesfield.

G. C. emaryinata. — Maxillary plate, left lower jaw: length 2 inches
5 lines ; depth at the symphysis I inch 8 lines ; ditto at the medial

on new species of Fossil Chimceroid Fishes. 53

angle of the dental edge 1 inch 1 line ; dental edge 1 inch 7 lines ;
anterior division 1 inch ; posterior division 7 lines ; heel (mutilated)
7 lines ; exterior flat, marked by fine vertical striae ; depression at
the heel circular, deep and broad ; dental edge deeply indented in
the form of two semicircles ; symphysis straight. Stratum, great
oolite : locality, Stonesfield.

7. C. rugulosa. — Maxillary plate, left lower jaw : length 1 inch ;
depth at the symphysis 4 lines ; ditto at the medial angle of the
dental edge 3 lines ; dental edge 6£ lines ; anterior division 3 lines ;
posterior ditto 3| lines ; heel 3^ lines ; exterior rugose ; one strong
depression near the heel striated vertically ; anterior division of the
dental edge concave ; posterior ditto ditto nearly straight. Inner
surface : triturating tubercles placed very obliquely. Stratum, great
oolite : locality, Stonesfield.

8. C. helvetica. — Maxillary plate, right lower jaw : length 2 inches
5 lines ; depth at the symphysis 1 inch 4 lines ; anterior division of
the dental edge 1 inch 4 lines ; breadth of ditto 8 lines. This spe-
cimen being much mutilated, the measurements are incomplete.
It approaches more nearly to C. Mantelli than to any other species.
Stratum, molasse : locality, CEtmaringen, canton of Argovie.

9. C. Dutelrii. — Maxillary plate, left lower jaw : length 4 inches ;
depth at the symphysis 2 inches 2 lines ; breadth of ditto 7 lines ;
depth at the medial angle of the dental edge 2 inches 2 lines ; dental
edge 3 inches 6 lines ; anterior division of ditto 1 inch 8 lines ; width
of ditto 8 lines ; posterior division of ditto 1 inch 8 lines. This tooth
is broad and strong ; the exterior is marked with indistinct undu-
lations ; the depression at the heel is nearly horizontal. Inner sur-
face : symphysis rather oblique ; the triturating tubercles broad, and
worn down less obliquely than in C. Townsendi, to which species this
most nearly approximates. Stratum, Kimmeridge clay : locality,
Boulogne.

10. C. Beaumonti. — Maxillary plate, right upper jaw : length of
the outer margin 3 inches 5 lines ; length of the inner ditto 2 inches
8 lines ; breadth at the base 1 inch 6 lines ; depth of the symphysis
5 lines ; breadth of the principal tubercle 6 lines ; the upper surface
is marked by a deep sulcus, 7 lines in width, running parallel with
the symphysis ; the inner surface has four triturating prominences,
one anterior, two basal, and one intermediate. Stratum, Kimme-
ridge clay : locality, Boulogne.

1 1. C. Dufrenoyi. — Maxillary plate, left lower jaw; length 2 inches
4 lines ; depth at the symphysis 1 inch 1 line ; ditto at the medial
angle of the dental edge 1 inch 4 lines ; dental edge 1 inch 5 lines ;
anterior division of ditto 7 lines ; breadth of ditto 5 lines ; posterior <■
division of ditto 8 lines ; heel 1 inch ; exterior slightly concave and
uneven ; inner surface contracts rapidly in diameter in the direction
of the base ; anterior tubercle 1 inch 6 lines in length by 6 lines in
breadth, placed very obliquely ; posterior tubercle small and narrow.
Stratum, Kimmeridge : locality, Boulogne.

The author then enters into a detailed comparison of the fossil
Chimeeroids with the recent genera Chimccra and Callorhynchus, and

54

Geological Society.

after pointing out the discrepancies both of form and structure which
they present, suggests the propriety of withdrawing them from the
genus Chimcera, under which they have hitherto been arranged.
The remainder of the memoir is devoted to a comparison of the fossil
species with each other, and the author concludes by proposing to
class them under three genera, as shown in the following tabular
arrangement.

(1.) Ischyodus {la\vs robur, olovs dens).

Two intermaxillary and two maxillary plates in the upper jaw ;
two maxillary plates in the lower jaw ; intermaxillaries thick and
strong, truncated more or less obliquely at their extremities. Struc-
ture : horizontal laminae inclosed by parietes of coarse fibrous dentine.

Upper maxillaries : triangular plates articulating with each'other
and the intermaxillaries on the medial line of the palate ; upper sur-
face provided with a deep sulcus parallel to the symphysis for attach-
ment to the jaw ; under surface with four triturating prominences,
one in advance, one on the outer margin, and two side by side near
the base, the larger one occupying the inner position ; structure of
the tubercles coarse and tubular ; the remainder of the teeth fibrous
and bony. Lower maxillaries : large and broad, formed for crushing
rather than cutting ; two tubercles, one at the heel, the other in ad-
vance ; symphysis broad ; the base invested by the membrane of the
mouth, the crown by a coat of hard enamelloid dental substance ;
structure of the anterior angle as in the intermaxillaries, of the re-
mainder as in the upper maxillaries ; position of the plates more or
less oblique.

SPECIES.

Ischyodus, Egerton.
Agassizi, Buckl. . . .
Beaumonti, Egert. .
brevirostris, Agass.,
Bucklandi, Egert. .

Colii, Buckl

curvidens, Egert. .
Dutetrii, Egert. . . ,
Duvernoyi, Egert. ,
Egertoni, Buckl.. . .
emarginatus, Egert.
falcatus, Egert. . . .
helveticus, Egert. .
Mantelli, Buckl. . . .
neglectvs, Egert.. . .

Oweni, Buckl

psittacinus, Egert. .
rugulosus, Egert. .
Tessoni, Buckl. . . .
Townshendi, Buckl.
Sedgwicki, Agass. .

Chalk- marl ....
Kimmeridge clay

Gault

Great oolite. . . .

ditto

ditto

Kimmeridge clay

ditto

ditto

Great oolite. . . .

ditto

Molasse

Chalk

Great oolite ....

ditto

ditto

ditto ,

Oolite

Portland ,

Greensand

Hamsey.
Boulogne.
Folkstone.
Stonesfield.

Ibid.

Ibid.
Boulogne.

Ibid.
Shotover.
Stonesfield.

Ibid.
Argovie.
Lewes.
Stonesfield,

Ibid.

Ibid.

Ibid.
Caen.
Milton.
Cambridge.

Mr. S. P. Pratt on the Geology of Bayonne. 55

(2.) Elasmodus {eKuayta lamina, dlovs dens).

Two maxillary and two intermaxillary plates in the upper jaw ?

Two maxillary plates in the lower jaw ; lower maxillary thick and
strong ; tubercle single, composed of a dental substance resembling
in structure a tritor of Psammodus ; in advance of the tubercle the
tooth is composed of several series of laminae, arranged in juxta-
position and inclined downwards and outwards ; behind the tubercle
the dental edge is notched, in consequence of a columnar structure
pervading this region of the tooth. The outer surface is enveloped
by a coat of dentine.

SPECIES.

•

STRATUM.

LOCALITY.

Elasmodus, Egerton.

1. Greenovi*, Egert.

2. Hunterif, Egert. . .

London clay.

A single specimen in the Hunterian collection affords the type of
a third genus.

(3.) Psaliodus (xpaWs forfex, and odovs dens).

Upper jaw ? Two maxillary plates in the lower jaw. Lower max-
illary like Chimcera, but without a triturating tubercle ; structure
homogeneous ; outer surface reticulated. Sp. Psaliodus compressus,
Egerton. It is supposed to be From the London clay.

" On the Geology of the Neighbourhood of Bayonne." By Samuel
Peace Pratt, Esq., F.R.S.

After noticing the published descriptions of the geological struc-
ture of the neighbourhood of Bayonne, by M. Dufrenoy, M. le Conte
D'Archiac, and M. de Colligno of Bordeaux, the author proceeds
to detail the result of his own observations in that locality in 1842.

Bayonne, situated at the junction of the rivers Adour and Nive,
about four miles from the coast, is nearly surrounded by low hills of
sand and gravel, those on the north side of the river being appa-
rently a prolongation of the beds of pudding-stone and gravel which
form a ridge extending from Tarbes to Pau, in a direction nearly
east and west to the coast. The gravel and alluvium on the south
differs in mineralogical character, and forms a thin coating to a suc-
cession of deposits of sand, clay and impure limestone which rise to
the south-west towards the coast. The sandy limestone, which is
composed almost entirely of Lenticulites complanatus and Nummulites
Biarritzana {N. elegans?), with a few fragments of shells, chiefly
Pectens, forms for a short distance the north bank of the river
Nive, rising at an angle of 20° or 30°. It is for the most part
covered up by beds of sand and variously coloured clays, resembling
the plastic clay. The gravel is very variable in thickness and con-
tains no flint, but is chiefly composed of rounded and irregular
masses of sandstone very like the Bagshot sandstone. The country
in this direction has been much disturbed.

About four miles in a south -west direction from Bayonne is the vil-

* Chinijcra Greenovii, Jgassiz. f Chimsera Hunteri, Owen.

56 Geological Society : Mr. Pearce on the

lage of Biarritz, near which there is an excellent coast section. The
sands and clays have nearly thinned off before reaching the cliffs
which rise from beneath the dunes, about a mile and a half to the
north-east of the village, and vary in height from 20 to 80 feet. In
a small bay called the Chambre d'Amour the beds are well seen, con-
sisting of strata of sandy argillaceous limestone, from a few inches
to five or six feet in thickness, all containing fossils in greater or
less abundance. Several faults occur between the first rise of the
strata and the village, by which the upper beds are repeatedly
thrown to the level of the shore. The organic remains vary con-
siderably in the several beds throughout the series, but Lenticulites
and Nummulites characterize the whole ; corals are numerous, but
shells more rare. In the disturbed strata at Biarritz all the Echino-
dermata, which are very numerous, have been found.

Among the fossils at the Chambre d'Amour are, besides the fora-
minifera before mentioned and numerous corals, the following mol-
lusca : — Pholadomya margaritacea, Venus transversa, Pinna marga-
ritacea, Spondylus radula, Gryphcea vesicularis ? Pecten arcuatus
and tripartitus, Solcn strigilatus, and Teredo articulata ; also Turri-
tella carinifera, Pyrula nexilis and Triton appeninum. Ditrupa subulata
and several Serpulee accompany them.

Passing the disturbed beds, strata of calcareous rock, more or less
argillaceous or arenaceous, alternating with a bluish clay or marl,
rise regularly at an angle of 60° or 70°, and are continuous for
nearly a mile, forming cliffs above 120 feet high. The uppermost
of these beds is chiefly composed of Nummulites and Lenticulites, the
arenaceous strata contain numerous and well-preserved corals, the
species of which have not as yet been determined, though referred
by D'Archiac to cretaceous forms. In the lower beds the best iden-
tified tertiary forms were found mingled with species hitherto re-
garded as cretaceous, such as Serpula ampullacea and S. rotula.
Among the mollusca occurred Spondylus rarispina, Ostrcea spathu-
lata, Dentalium grande, Turritella carinifera, Scalaria semicostata and
acuta, Cerithium turritellattim and cinctum, with several undetermined
species of various genera.

The cliffs cease for a quarter of a mile, being terminated by a
fault, when the strata again rise at a small angle in the same direc-
tion. Their mineralogical character however is different, as they
consist of a marly light- coloured limestone, abounding in fossils
which are mostly distinct from those of the preceding beds, with
the exception of the corals. The protrusion of igneous rocks has
changed this limestone in places into a hard crystalline marble
or dolomite. In this part of the series were found Terebratula bisi-
nuata and striatula. Another fault throws these beds beneath the
shore, and at an interval of a few hundred yards they are succeeded
by a series of cretaceous beds resembling chalk marl, the general
inclination and direction of which, on account of frequent disturb-
ances, are difficult to determine, but appear to be the same with
the last-mentioned strata. The cliffs formed by the cretaceous
strata rise to a height of from 50 to 150 feet. Three or four species

Locomotive and Non-locomotive Crinoidea. 57

of Nautilus and Ammonite, and a few bivalves, chiefly Inoceramus
Cuvieri, are found in them, but there is no fossil common to the beds
separated by the last-mentioned fault.

The beds overlying these undoubted cretaceous strata have been re-
ferred by the French geologists, quoted by Mr. Pratt, to the upper
part of the cretaceous system, both on account of the superposition
and direction of the strata and of the contained fossils, which they
regard as cretaceous species. But a closer examination of the or-
ganic remains shows that such as may be identified with known
species are mostly tertiary forms, while such as appear to be creta-
ceous, belong to genera and species of variable and uncertain cha-
racter. The Echinodermata, as identified by Dr. Grateloup, do not
agree with the references, except one, which is a tertiary species.
The variation in the mineralogical character of the beds sufficiently
accounts for the gradual change of species observed from the first
rise of the strata to their termination. Certain species were common
to all the beds preceding the second fault. The deposit is appa-
rently covered in its upper part by the plastic clay, to which it
approaches nearest in mineralogical character. At Dax and at
Royan similar deposits under similar circumstances were observed
by Mr. Pratt.

On the whole, the author concludes that the characters of the
deposits in question are tertiary, and that they may probably be
placed earlier in the series than any described Eocene beds (unless
we except the Diablerets and some other deposits allied to them in
position and palseontological characters). The whole of the Biar-
ritz beds have apparently been elevated at a period posterior to the
elevation of the chalk, the elevating causes disturbing at the same
time the neighbouring cretaceous beds.

March 8. — A paper was read " On the Locomotive and Non-loco-
motive powers of the Family Crinoidea." By J. C. Pearce, Esq.,
F.G.S.

The author is induced, from an examination of the various modes
of attachment among the Crinoidea, to separate those animals into
two great groups, the Non-locomotive and the Locomotive. The
former, when once attached to any solid substance by their base or
foot, were immoveably fixed ; the latter possessed the power of grasp-
ing with the foot any substance, and again relaxing their hold at
pleasure. The non-locomotive Crinoidea he subdivides into solid-
footed and root-footed. In the solid-footed the foot is formed like
an irregular cone with the base downwards, and is composed of suc-
cessive laminae, which envelope the inferior part of the column and
increase in number as the animal advances in age. This base or
foot is generally found firmly adhering to the rock in the fossil state,
although specimens are sometimes found detached which appears to
have been caused by violence during life. The columns of all the
species which Mr. Pearce has examined are very short and destitute
of side-arms. He enumerates Encrinites moniliformis from the Mus-
chelkalk, Apiocrinites rotundus from the Bradford clay, and Cyatho-
crinites tuber culatus from the Dudley limestone, as examples of this

58 Geological Society : the Rev. W. B. Clarke

group. In the non-locomotive root-footed Crinoids the hase is com-
posed of many root-like branches, radiating in a more or less hori-
zontal or downward direction from the lower part of the column,
each branch bifurcating several times in an irregular manner. The
branches are perforated by a central foramen, and appear to be com-
posed in individuals of all ages, of a solid calcareous substance in-
capable of motion.

Mr. Pearce divides his locomotive Crinoidea into two sections,
Branch-footed and Sucker -footed. The branch-footed are charac-
terised by the organ of attachment, or foot, being composed of a
number of jointed branches, in some species simple, in others bifur-
cating, or dividing in an irregular manner, and generally terminating
in a minute blunt point. Each joint has a central foramen, and is
articulated by alternate radiating ridges and grooves, admitting of
the greatest degree of flexibility, forming an organ which the author
regards as well adapted to crawl along the bottom of the ocean, or
to steady the animal against the motion of the water. The columns
of this group are generally furnished with side-arms, extending to a
greater or less distance from the foot, and sometimes the whole
length of the column. Examples are, Apiocrinites ellipticus from the
chalk, Pentacrinus Briareus from the lias, Actinocrinites tessellatus,
Platycrinites gigas, and several undetermined species from the moun-
tain limestone ; also Cyathocrinites goniodactylus, and several unde-
termined species from the Dudley limestone.

The sucker-footed locomotive Crinoids have the column destitute of
side-arms, and terminating at its inferior extremity in a blunt point.
Mr. Pearce subdivides them into Crinoideform and Comatuliform.

The following table exhibits Mr. Pearce's views of the classification
of the family Crinoidea.

Fam. Group.

Non-loco-
motive

1

locomotive ■

Division.

Solid-footed .
Root-footed....
Branch-footed.

Sucker-footed •

Subdivision.

Crinoideform
Comatuliform.

Genus.

Apiocrinites
Encrinites
Cyathocrinites
Eugeniacrinites

Cyathocrinites

Apiocrinites

Pentacrinus

Actinocrinites

Platycrinites

Cyathocrinites

Actinocrinites

Apiocrinites

Species.

rotundus.

moniliformis.

tuberculatus.

nutans.

quinqueangularis.

rugosus.

ellipticus.

Briareus, jun.

tessellatus.

gigas.

goniodactylus.

moniliformis.

fusiformis.

" On an entirely new form of Encrinite from the Dudley Lime-
stone." By J. Chaning Pearce, Esq., F.G.S.

The fossils described in this communication were discovered by
Mr. John Gray of Dudley. Mr. Pearce regards them as constitu-
ting a new genus which he proposes to name Pseudocrinites, inclu-
ding two species both having "the arms and fingers inserted in
bands, which commence just above the column and pass over the

on a Fossil Pine-forest in Australia.

59

plates of the head to its summit." The one form has two, the
other four ranges of " fingers." They resemble each other in
having " the columns at their superior part composed of rings, gra-
dually increasing in size towards the head. The plates of the head
are thin and broad, and marked on their outer surface by lines of
growth, and radiating ridges resembling the plates of the marsupite.
They are also furnished with four orifices of a lozenge shape, most
singularly inserted in the plates of the head, and their arms and
fingers are exceedingly short. The fingers are composed of two
rows of bones, each bone on the one side being inserted between
two of the opposite. These fingers appear to be placed in four rows
on each of the hands, and pass off from the head in a radiating di-
rection, commencing at the column and uniting at the summit."
Mr. Pearce names the first species Pseudocrinites bifasciatus, and the
second P. quadrifasciatus .

" On a Fossil Pine-forest at Kurrur-kurran, in the inlet of
Awaaba, on the eastern coast of Australia." By the Rev. W. B.
Clarke, A.M., F.G.S.

Awaaba is one of those inlets which occur at frequent intervals
idong the eastern coast of New South Wales, and which, from their
sea-entrance being usually narrow and blocked up with drifted sand,
are by the colonists termed " Lakes." Awaaba is called Lake Mac-

quarrie, and is the largest of the inlets of that description between
Port Stephen and Broken Bay. Its sea- entrance lies fourteen miles
to the south of the mouth of the Hunter river, nearly in 33° south
latitude.

This inlet occupies a portion of that formation of conglomerate

60 Geological Society: the Rev. W. B. Clarke

and sandstone, with subordinate beds of lignite, which extends from
the Hunter river southwards towards Brisbane Water. The lignite
constitutes the so-called Australian coal. This formation, owing to
its beds along the shores of the inlet being placed horizontally, and
being divided by nearly vertical joints, gives rise to regular lines of
coast, both in a longitudinal and transverse direction. It forms
along the coast a high range, which, except at the entrance, divides
the lake from the sea. Within the lake a series of extensive bays,
bounded to the water's edge by steep cliffs, run out like fingers,
far up into the country. The water of the inlet is for the most
part very deep.

On the western side of the lake, and nearly opposite its sea-
entrance, a promontory, bounded on either side by a bay, is formed
by the Tirabeenba mountain, which stretches from the S.E. to the
N.W., and in the latter direction ends abruptly in a lofty but not
very precipitous escarpment : this sudden termination is occasioned
by a fault. This mountain range then turns to the W., and after-
wards to the S.W. ; between it and the next range a wide valley
intervenes.

The north-eastern flank of the north-western extremity of this
range swells out into a hill of low elevation, from the base of which
to the water's edge a low flat extends ; the flat is about fifty yards
broad, and is, in point of level, within a foot of the surface of the
water ; it continues along the base of the slope for the space of about
half a mile : it is called by the aborigines Kurrur-kurran. To the
south and west of this flat the slopes of the mountain come down to
the margin of the lake. The surface of the flat is composed of black
sandy vegetable mould, and of detritus thickly interspersed with the
roots of plants and grasses; trees of large growth, which are prin-
cipally Eucalypti and Casuarinae, together with some others of smaller
dimensions, stand at intervals upon it, and grow even close to
the water. Beneath the alluvial matter the rock occurs in situ : this
is a sandstone, which is for the most part of a compact and semi-
crystalline texture, approaching to chert ; its strata run out to some ,
distance, at a small depth below the surface of the water, and render
the lake in that part very shallow.

Throughout the whole of the alluvial flat, stumps and stools of
fossilized trees are seen standing out of the ground, and one can
form no better notion of their aspect, than by imagining what the
appearance of the existing living forest would be if the trees
were all cut down to a certain level. In the lake also, where it ad-
joins the flat, to the distance of from 80 to 200 feet from the shore,
numerous points are seen, like -those of a reef of rocks, just peeping
above the surface of the water ; these points are the fossilized stools
and stumps of tree, similar to those which are found on shore. The
greater part of these stems, both of those on land and in water, stand
vertically ; many of those on shore have remains of their roots in the
sandstone rock beneath the alluvial matter ; and of those which stand
in the water, one at the distance of three feet from the shore has
portions of its roots imbedded in the sandstone on which it rests.

on a Fossil Fine-forest in Australia. 61

The rock immediately round the roots is not of so harsh a texture as
it is in other parts ; in it, in the neighbourhood of the roots which
are in the water, there appear numerous white spots, which give the
stone a mottled appearance : this arises from a multitude of small
cavities which contain powdery silex, similar to what is often found
in the cavities of chalk-flints. On the shore, the surface of the rock
near the stems is worn into a number of little holes, which are owing
to the decay and removal of this powder. Mr. Clarke sees no other
explanation of these specks, than that they mark the situation of the
fibres which proceeded from the roots. The roots of the trees are
in some instances surrounded by an accumulation of sandy rock,
which forms a mound of a higher level than the rest of the stratum.
The roots do not descend, so far as has been ascertained, very far
into the substance of the rock, nor is there any appearance of a
dirt-bed. The stools stand from two to three feet above the surface
of the ground, and vary from two to four feet in diameter ; but one in
the lake is at least four feet above the level of the water, and five or six
feet in diameter. In several of the stumps from 60 to 120 concen-
tric rings of growth may be counted : a few of the stools are hollow
in the centre, but others are solid throughout : the wood appears to
be coniferous. Veins of chalcedony traverse the substance of the
trunks between the concentric rings, and also in the direction of the
radial lines.

Many of the stems at Kurrur-kurran have the bark adhering firmly
to the trunk, and the bark in one instance was of the thickness of
three inches. Its appearance in one or two cases was such as to
show that it had been partly torn from the tree while yet standing,
as if it had been broken down and the bark had been rent by the fall.
The colour of the substance of the stems within varies from a
grayish white to a clouded gray, but their surfaces, when exposed to
the air, have become yellowish by weathering ; many are overgrown
by lichens, and have then exactly the appearance of the stumps of
recent trees. The upper extremities of the fossil stumps present
clean horizontal sections, which shows that they were not broken off
while recent, since no mode of fracturing recent pinewood could have
occasioned such neat, plain and parallel sections as the summits of
these stumps exhibit.

In a fragment of the sandstone from the base of one of the fossil
stumps, the silicified impression of part of the leaf of a Glossopteris
was found.

Immediately below the flinty stratum in which the trees are found
is a bed of lignite ; above the level at which the trees occur,
there are found, imbedded in the sandstones and conglomerates,
immense quantities of broken fragments of trees, apparently stripped
of their boughs and branches. These fragments are generally di-
vested of their bark, and appear to have been drifted.

Fossil trees are found in this formation at other places, and nearly
at the same level above the sea as at Kurrur-kurran ; they occur in
sandstone similar to that of Kurrur-kurran, at the southern extre-
mity of the Tirabeenba mountain, immediately above and below a

62 Geological Society.

bed of lignite. At the spot referred to, pits have very recently been
opened for working the lignite, at the level of about four feet above
the surface of the lake. At the south head of Reid's Mistake, which
is the name for the sea-entrance to the inlet of Awaaba, similar beds
of sandstone occur, and these are traversed vertically by the trunks
of trees, while other trees lie horizontally in the same beds. Lines
of division, which appear to be owing to the contraction of the whole
mass, intersect both the trees and their matrix : these trees are found
at a somewhat higher level than the sea. At nearly the same level
in Nirritinbali (or Mutton-bird Island), off the entrance to Awaaba,
large stools and stems of trees occur in conglomerate, which conglo-
merate reposes on beds of lignite. Fossil trees are also found in
conglomerate reposing on lignite on the coast north of the entrance
to Awaaba, at Redhead, at Newcastle, and at Nobby's Island, off the
mouth of the Hunter river. At Nobby's Island the trees lie in a pebbly
grit, passing into conglomerate, and are mineralized by hydrate of iron ;
they are from 10 to 150 feet long. At none of the above places,
however, do the trees occur in such profusion as at Kurrur-kurran.
Fragments of roots and of the boughs of trees, divested of their
bark, are found at Munniwarree, Wollogong and Mulibinbak, im-
bedded in beds of sandstone at a higher level than the beds which
contain the fossil trees. Similar fragments are found spread over
the surface at Wollon Hill, at Holworthy Down, and elsewhere in
the colony ; it is probable therefore that the bed of sandstone con-
taining trees in a vertical position, which is found nearly at the same
level above the sea at Kurrur-kurran and the other places above-
mentioned, is the true geological position of that ancient forest from
which the enormous quantities of the fragments of wood which occur
either spread over the surface, or imbedded in the sandstone above
and below the lignite, have been derived.

The sandstones of this formation, and in this vicinity, have been
powerfully affected by the action of intrusive rocks ; they are tra-
versed, at Nobby's Island and on the coast near Newcastle, by trap
dykes. The author refers to the 'Voyage' of Flinders, page 131,
for an account of mineralized fossil wood found in Bass's Straits, at
Reservation Island, which is composed of granite and of schist, tra-
versed by granite veins and trap dykes. He also refers to the ' Tasma-
nian Journal,' vol. i. p. 27, for an account, by the surgeon of H.M.S.
Erebus, Dr. M'Cormick, of silicified wood found in association with
trap rocks in Kerguelen's Land ; and to the same volume, p. 24, for
an account by Dr. T. D. Hooker, assistant-surgeon to H.M.S.
Erebus, of fossil wood found at Macquarrie plains, in Tasmania.

The author infers, from the present position of the fossil trees at
Kurrur-kurran, that the land must have been alternately depressed
and elevated. He makes mention in the course of his paper of two
beds of lignite, one above the bed of fossil trees and one below it ;
but he does not describe the relative position and distance of these
two beds.

March 22. — A paper was read " On some Pleistocene Deposits near
Copford, Essex," by John Brown, Esq.

Mr. J. Brown on Pleistocene Deposits near Copford. 63

The order of the component beds of these deposits was taken from
a cutting made for the Eastern Counties Railway. The lowest bed
noticed consists of blue clay, which the author refers to a great
detritic accumulation called "till," and which occurs extensively
over the northern portion of the county of Essex. The till varies
considerably in character and composition ; at the N. extremity of
the section which the author exhibited, it was described as consist-
ing of a stiff* tenacious clay, but within a short space it changed
to a sandy gravel, containing fishes' teeth and corals in great abun-
dance : the rock fragments have been derived from basaltic and se-
condary beds ; the latter afforded the fossils contained in the follow-
ing list, for the identification of which the author states that he
has been indebted to Mr. J. de C. Sowerby. Serpula illium, L. ;
S. tetragona, L. ; S. articulata, G. S. ; <S. granulata, C. ; Terebratula
rigida, U. Ch. ; T.pisum, Ch. M. ; T. striatula, L. Ch. ; Gryphcea in-
curva, L. ; G. dilatata, K. C. ; Inoceramus,C; Avicula incequivalvis, L.;
Exogyra virgula, K. C. ; Crania striata, C. ; Pollicipes maximus, C. ;
Ammonites Leachii, K. C. ; A. annulatus, L. ; A. dentatus, G. ; A.
spinosus, K. C. ; A. serratus, O. C. ; Belemnites acutus, L. ; B.pistil-
liforniis, L. ; Littorina carinata, G. S.; Pentacrinites basaltiformis, L.;
Encrinites moniliformis, O. The remains of fishes were, Otodus appen-
diculatus, C. ; Galeus pristodontus, C. ; Notidanvs pristis, C. ; Odon-
taspis rhaphiodon, C; Hybodus, U. O., which were determined for the
author by Mr. S. P. Woodward.

The Pleistocene deposit at the Copford brick-field consists, in an
ascending order, of a bed of black vegetable matter, or peat, from
six inches to one foot in thickness, resting immediately upon the
" till :" from this stratum the following shells were procured, which
were named for the author by Mr. S. P. Woodward : — Vertigo pa-
lustris ; V. edentula ; V. pusilla ; V. pygmea ; V. substriata ; Azeca
tridens ; Acme fusca ; Carychium minimum ; Zua lubrica ; Clausilia
Rolphii ; CI. nigricans ; CI. bidens ; Succinea Pfeifferi ; S. putris ;
Aplexus hypnorum ; Limnius j>alustris ; L. truncatulus ; Planorbis
spirorbis ; P. vortex ; Pisidium pusillum ; Helix nemoralis ; H. hor-
tensis ; H. arbustorum ; H. lapicida ; H. rufescens ; H. hispida ; H.
pulchella ; H. lamellata ; H. spinulosa ; H. fulva ; Zonites rotunda-
tus ; Z. ruderata ; Z. cellarius ; Z. radiatulus ; Z. nitidulus ; Z. lu-
ridus ; Z. crystallinus ; Pupa anglica ; P. umbilicata ; P. marginata.

Above the peat is a bed of clay and detritus about one foot thick,
containing many of the land and freshwater shells cited above ; next
above this is a second layer of peat with shells.

At the southern extremity of the author's section, the order of the
beds was as follows: — 1. Diluvial clay, 3 feet. 2. White sand with
shells, 3 feet. 3. White calcareous marl with shells, together with
the bones of the elephant, ox and deer. 4. Peat with shells ( Val-
vala pis cinalis), 6 inches. 5. Blue clay with freshwater shells.

The author suggests that this deposit is the bed of an ancient
pond, which occupied a depression on the surface of the till.

A paper was afterwards read " On the Tin Mines of Tenassirim
Province." by Prof. Royle.

The author commences by observing that though tin is found in

64 Geological Society.

few parts of the world, yet that it can be clearly proved to have
been employed from very early historical times : he next enters
into various interesting inquiries respecting the names under which
it was known by the several nations of antiquity, and the country
from whence it was procured, considering it more probable that the
Greeks and Romans were supplied from the East, than that com-
merce should have extended in very early times to such a remote
country as Cornwall.

After some short notices of the old geographers and travellers
who have spoken of the tin of India, the author enters into an ac-
count of the several localities in which it has been discovered, the
situations in which it usually occurs, and the methods of extracting
and smelting it.

The island of Banca, situated at the eastern extremity of Sumatra,
is the most celebrated of the Indian tin districts. The surface of
this island presents short ranges of granitic hills, flanked by inferior
ones which abound in red ironstone. The tin occurs in the low
alluvial deposits at the base of the granitic hills, and about twenty-
five feet from the surface. The ore is a peroxide of tin yielding
about 60 per cent, of metal. From 1813 to 1816, whilst the island
was in possession of the East India Company, three millions of
pounds were raised annually, and since that time the quantity is
believed to have increased. It is stated on the authority of Captain
Tremenhere, that some of the tin of Banca is extracted from the
side of a hill about 300 feet high.

The island of Lingen, at the southernmost point of the peninsula of
Malacca, particularly in the neighbourhood of Palembang on the east
coast, also produces tin, as does the island of Sumatra at various points
along the eastern coast, and near Bencoolen on the western coast.

The whole peninsula of Malacca on its west side is also a stanni-
ferous district. A range of lofty granitic hills runs from north to south
through this country : the lower ridges of the neighbourhood of Ma-
lacca consist of conglomerate, with clay ironstone, which agrees in
character and composition with a rock common on the Malabar coast,
described by Dr. Buchanan under the name of Laterite. Severe shocks
of earthquakes are occasionally felt in Malacca ; and there are several
springs with temperatures of 110° and 180° F. The tin ore is ex-
tracted from the low alluvial plains at the base of the granitic range,
and is not unfrequently mixed with gold. The exported quantity of
the latter amounts to about 19,800 oz. annually. The ore occurs
in the horizontal seams of considerable extent, and from six to
twenty inches in thickness, at a variable depth from the surface.

The author next describes the native processes for working and
smelting the ore, and states that about 70 per cent, of metal is ob-
tained at a cost of twenty-three shillings the cwt. : on the author-
ity of Capt. Newbold, the gross annual quantity of tin raised in the
peninsula of Malacca is given at 4,325,000 lbs.

The British provinces on the coast of Tenassirim contain about
30,000 square miles, having a north and south range of mountains
for their eastern boundary. The mineral products of these provinces
are tin, iron, and coal. The north and south range is stated by

Mr. Austen on the Geology of the South-east of Surrey. 65

Dr. Heifer to be composed of granite and gneiss ; and the northern
and middle parts of the country to consist of transition slates and
limestones. The country south of the Maulmain river, the province
of Ye, towards Tavoy, is a sterile slate district covered with bamboo.
Amherst province presents isolated ridges of limestone with fertile
land at their bases : to the south are sandstones and conglomerates.
Tertiary formations, chiefly argillaceous, occupy the higher parts of
Amherst and Ye provinces, the plains of Tavoy and Kalleevung, those
between Tavoy and Poilon, the valley of Jaun-biank and of the Te-
nassirim river, and the elevated land of Meta-mio.

In 1837 Dr. Heifer discovered tin near lake Loadut, about 110
miles N.N.E. of Maulmain, and in 1840 he reported the country to
the north of the Pakehan river to be the richest stanniferous district
within the Tenassirim provinces : the ore is found in the debris of
primitive rocks, and the range is stated to be a continuation of the
Siamese tin district of Rinowng. Domel island and the banks of
the Boukpeer are also cited as localities yielding tin.

Capt. Tremenhere's account of the tin of the Tenassirim provinces
is, that it occurs chiefly in the beds and banks of those rivers which
issue from the primitive mountains : on the Thengodong river, in
the immediate vicinity of the coal mines on the Great Tenassirim
river, 11,889 grains of peroxide of tin were collected in an hour and
a half. Along the courses of the streams which flow into the Little
Tenassirim river it occurs in thin beds, in gravel ; and Capt Tremen-
here calculates, from a short trial he made, that two men could ob-
tain by washing the gravel about 5 lbs. 2 oz. 464 grs. of tin per day.

At Kalian, on the right bank of the Great Tenassirim river, eleven
miles from Mergui, Capt. Tremenhere found a vein of tin about
three feet and a half wide, nearly vertical, and included in a white
decomposing granitic rock. The ore is described as equal to that
from Banca. It is conjectured that tin may ultimately be found in
the small isolated granitic hills which rise out of the alluvial plain
in the neighbourhood of Kahan.

April 5. — A paper was read " On the Geology of the South-east
of Surrey." By R. A. C. Austen, Esq., Sec. G.S.

The observations embodied in this paper relate to certain points
regarding the structure of the district on either side of the North
Downs of Surrey, to the number and order of the component forma-
tions, and the evidences which they present of the conditions under
which they were formed.

Mr. Austen regards the steep walls of the chalk formation as
forming a more obvious physical boundary of the Wealden formation,
especially on the south, than the great escarpment of the greensand.
He remarks that the subdivisions of the eocene tertiary present lines
of escarpment corresponding to the secondary series. He maintains
that the Wealden in its present state is not a valley of elevation, —
that at some former period it has been an elevated area, but that
subsequent changes in the relative positions of the earth's crust have
reduced the elevation which this particular portion must have had at
a given time, and with reference to other circumjacent areas.

Phil. Mag. S. 3. Vol. 24. No. 1 56. Jan. 1 844. F

66 Geological Society,

Numerous sections show that the lowest tertiary strata in the
vicinity of the chalk escarpment are composed of rounded pebbles,
fine sand, and heds of oyster-shells, the whole corresponding exactly
with the Reading and other equivalent deposits. Mr. Austen infers
from these facts that the movements of the earth's crust, which have
heen considered as having been confined to the Wealden district, can
be traced into the tertiary area of Surrey and Hants, and that these
movements and the process of removal did not commence until after
the completion of the lower tertiary series.

Cretaceous Series.

The general character of that portion of the chalk which is exhi-
bited in the range from Farnham to Dorking, as regards the distri-
bution of animal remains, is as follows. Great as is the still remain-
ing thickness of chalk in the south-east of England, we must always
bear in mind that in every place in which we observe it, it has been
extensively abraded and reduced. To what extent this has taken place
we can only conjecture from such loose calculations as those made on
a comparison of the beds of uninjured flints (such as occur over the
surface of the North Downs), and the relative proportion of the, flint
seams to the beds of pure chalk.

If we compare the flints which are collected in heaps, either from
the fields or dug near the surface along the North Downs, with such
as are to be found in every quarry of the upper chalk, the difference
is very striking. In the former every single specimen affords proof
that it has been formed round some spongiform body, and this too
is evident from the external form. With the flints in situ such forms
are rare, and warrant the conclusion that these curious productions
were much more abundant in the cretaceous ocean towards the
close of that period than they had been in any other portion.

A curious fossil, to which Mr. Mantell has given the name of
Spongus, is also not unfrequent in the flint and gravel beds, but
has never been observed by the author in beds in situ.

The most abundant remains contained in the beds, which are now
the highest, are Belemnites mucronatus, Pecten nitidus, Ostrea vesicu-
luris, Inoceramus cordi/ormis, Terebratula plicata, Marsupites ornutus,
Ananchytes ovatus, together with some undescribed Pectens and other
bivalve shells.

Below these beds are found others, with Inoceramus latus, Ventri-
culites radiatus, and Coscinopora infundibuliformis in extraordinary
abundance, the Catillus concentricus being the most common and
characteristic shell.

Throughout this upper portion of the chalk it is very evident that
the layers of flint are the equivalents of the partings between strata
in other deposits ; and sufficient time seems to have elapsed between
the completion of one stratum and the commencement of another,
to allow the lower one to become compact. The irregularities of the
flints are always on the upper side ; one seam in a pit near Merrow
consists entirely of the silicified remains of Ananchytes. These were
evidently all dead crusts which had lost their spines before they were

Mr. Austen on the Geology of the South-east of Surrey. 67

drifted over the bed where we now find them. This species however
is not confined to such layers, but is found in extraordinary numbers
in each separate bed ; and in another instance an Astrcea had time
to spread itself out over the surface.

Considering the small number of animal remains we yet possess
from the chalk formation, when viewed with reference to its vast
thickness, there being not more than four or five species to 100 feet,
it seems hazardous to refer the whole of this wide-spread mass of cal-
careous matter to the destruction of animal structures ; but the im-
pression constantly produced by a microscopic examination of the
white chalk in every place has been, that it was the deep sea deposit
of a wide ocean, which in parts teemed with animal life, but of which
the localities have long since disappeared in the extensive destruction
which it has everywhere experienced ; and that all we have to judge
from is such portion as was not generally calculated to support animal
life, with the exception perhaps of Foraminifera and Brachiopods :
the specific gravity of shells and corals is in favour of the wide dis-
tribution of their materials when pounded.

Nor is this purely hypothetical : there are some remarkable beds
a little below that portion of the deposit last described which bear
it out : they are beds which were apparently deposited when the
waters could drift rather coarser materials than usual ; so that the
greatest portion consists of broken branches of corals, shells and
Echinoderms, cemented by the usual comminuted matter of the or-
dinary chalk strata, Eschara cancellata, E. pyriformis, Cellepora bi-
punctata, Ceriopora madreporacea, Retepora truncata, Serpula plexus,
and Cidaris vesiculosa are the principal species met with.

For a very considerable depth below this, through that portion
where the seams of flint are most regular, it is almost in vain to
search for any traces of animal life. This condition of things is con-
tinued downwards as far as the chalk without flints, where Inocera-
mus mytiloides and Cuvieri,Lima Hoperi, Plagiostomce&ndTerebratula,
become abundant, together with the remains of fishes ; and which
beds are succeeded by others which afford a gray limestone, and con-
tain Ammonites rhotomagensis, A. Mantelli, A. lewesiensis, A, varians,
Turrilites tuberculatus, Scaphites tequalis, Pecten Beaveri, and Anan-
chytes radiatus.

This lower chalk, which through a considerable thickness had
been gradually becoming more compact, thick-bedded and dark-co-
loured, suddenly changes to a rock, exactly resembling the upper
white fragmentary beds. This portion of the series, taken in a de-
scending order, slowly acquires an admixture of sand and green
earth, so as to become first a craie chloritee, till by the further di-
minution of the calcareous matter we reach the bright green beds of
the upper greensand with Plicatula inflata : below these strata of
white, blue, calcareous matter again occur, containing Ammonites
rhotomagensis and Mantelli, offering a striking contrast to the beds
above them and the rock gault immediately below : through this
portion again traces of animal life are hardly to be found.

The gault clay contains Ammonites splendens, A. interruptus, A*

F2

68 Geological Society.

auritus, Baculites and Inoceramus gryphccoides, in considerable num-
bers, which are continued down into the beds of marly green earth
below.

This terminates a long- established division in the cretaceous series ;
and the abrupt manner in which some of the changes in mineral cha-
racter, as from clays to sands or limestone, takes place, is very re-
markable.

Greensand Series.

Dr. Fitton remarks *, that the tract on the south and west of Guild-
ford forms one of the most extensive surfaces of the lower greensand
to be found in England ; and he illustrates the succession of the strata
in this district by a section from Farnham across Hindhead to the
Weald. This line, however, which is taken near the western extre-
mity of the major axis of the Wealden denudation, does not exhibit
the disturbance to which the preservation of this larger area of lower
greensand is due ; and a better line for this purpose is one which
may be taken due south from the town of Guildford, and which will
cut across the small valley of denudation, which occurs within the
said area of the greensand formation, between the chalk range of the
North Downs and the escarpment of the Weald valley.

This denudation has cut through all the. beds of the greensand
series, as represented, and has laid bare, in the lower parts of the
valley, the clays of the Wealden series.

These clays are noticed by Dr. Fitton f, who states that his atten-
tion was first called to them by Mr. Murchison. The discovery of
Wealden fossils has enabled the author to confirm Dr. Fitton's con-
jecture as to the age of the lowest clays of the Pease marsh, which,
even without such aid, is sufficiently established by the general ar-
rangement of the greensand series which succeeds it. This structure
of the Pease marsh valley had been long known and mapped by Mr.
H. L. Long.

This valley of denudation is rudely elliptical, and like that of the
Weald, has its larger axes extended due east and west. The out-
ward dip of the beds is most clearly marked, and the general nature
of the disturbance can be easily traced by a series of transverse sec-
tions, along which the beds of the greensand will be seen to be raised
on the north and depressed on the south of the line of disturbance.

The author considers that an interesting and important member of
this group has been overlooked in England, and proposes to adopt (for
the south-east of England at least) the following subdivisions : —

a. Upper, ferruginous.

b. Middle, containing Bargate and Kentish Rag.

c. Argillaceous [Neocomian of Leymerie and D'Orbigny].

a. Upper [ferruginous} division. — This section, though founded on
an artificial character, is so decidedly marked, both as constituting
an independent range of hills parallel with the chalk, as also by the
absence of any useful vegetation, as to be most obvious of all the
three divisions of the lower greensand. As a mineralogical division
* Geol. Trans., vol. iv. p. 143. f Ibid, p. 149.

Mr. Austen on the Geology of the South-east of Surrey. 69

it is clearly defined. A clear line without any alternations separates
it from the dark-coloured beds of the gault, and though less clearly
marked below, yet its range across the country and numerous sec-
tions show that its thickness is uniform. A diagonal arrangement
of the bedding is very evident in a portion of it. Organic remains
are very rare. Mr. Austen has received one curious specimen from
Mr. H. Long, — an ironstone cast of the umbilical portion of an am-
monite. Fossil wood also occurs.

b. Middle division. — Next below the ferruginous division of the lower
greensand strata are sands with subordinate bands of hard siliceous
building stone, which have been fully described, first by Mr. Mur-
chison and subsequently by Dr. Fitton. Mr. Austen confines his
remarks to the indications which they afford of the condition of
things at the period of their deposition. These sands, which at first
sight appear non-fossiliferous over large areas, are found on closer
examination to contain numerous minute corals of undescribed spe-
cies, broken spines of Echinoderms and fragments of bivalve shells ;
all these are most abundant in the lines of the Bargate stone. Large
specimens of Nautilus radiatus and Ammonites nutfieldiensis occur
occasionally, and casts of a species of Mya are constantly found at
right angles with the beds, and in the position in which they live.

Throughout the middle division of the lower greensand the com-
ponent beds jjresent a diagonal structure. Many of the changes
which have taken place since the deposition of the strata, such as
the consolidation of the Bargate nodulates and ragstone, have been
in the lines of the cross-stratification. Mr. Austen regards this struc-
ture as indicating a moving power which acted constantly in one
direction ; and as in this case the inclination of the transverse beds
is always southerly, the materials of the middle green deposits appear
to have been, during a vast period of time, accumulated in a given
direction, and consequently derived from an opposite one.

c. Argillaceous division (Neocomian). — The beds which rest im-
mediately upon the blue Wealden shales of the valley of the Pease
marsh consist of brown and yellow clays. The range of these strata
at the base of the hills which bound this area is clearly marked,
either by several brick-fields or by the prevalence of oak timber ; and
sections showing the place in the series which it occupies may be
seen near the ford at East Shalford, and the Artington brick-field.
These clay strata often run out at the base of the lower greensand,
which gives them an appearance of greater thickness than they really
possess.

Though the general character of this portion of the cretaceous
series is argillaceous, it contains subordinate nodular concretions in
the lines of bedding, of great size and thickness, and cemented
into an exceedingly hard rock by calcareous matter. Corals and
shells are abundant in these nodules ; indeed these beds seem richer
in organic contents than any other portion of the cretaceous series :
good specimens however are difficult to obtain, as the outer surfaces
of the shells adhere very strongly to the matrix.

Besides the fossils contained in the calcareous nodules, the inter-

70 Geological Society.

mediate clay-beds contain in great abundance a large oyster, with a
coarse foliaceous structure. These beds form the lowest portion of
the cretaceous series in this part of England, and are either peculiar
to this locality or have been overlooked elsewhere.

A like argillaceous division occurs at the base of the greensand
escarpment of the great valley of the Weald, where also it advances
in the shape of an under terrace. At Parkhatch, near Hascomb,
these beds were cut through in digging a well, and found to rest
upon blue Wealden shales.

Strata have been described by some of the French geologists,
which correspond exactly in position, mineralogical character, and
included fossils with the argillaceous group above noticed. The
French strata occur at the base of the cretaceous series of the Paris
basin, and are described by Mons. Leymerie and Cornuel under the
names of the argile ostreenne, and the calcaire a Spatangues, and
belong to their Neocomian group. On this subject Mr. Austen has
the following remarks : —

In thus comparing the lowest argillaceous division of the green-
sand of the south-east of England with the Neocomian group of con-
tinental geologists, it may be well to consider what is the value
of that group, and how far it has hitherto been recognised in this
country. The fossils of the upper Neocomian beds of Vassy and the
department of the Aube are forty-two, of which only one (the Cor-
bula punctum of Phillips) is regarded as an English species, and even
that is quoted with a doubt. So far, then, the establishment of an
additional group to the cretaceous series, as described by English
geologists, has been strictly in accordance with the principles on
which most recent divisions have been made in older rocks ; and in
the absence of figures and descriptions of some of the remarkable
shells which this group contains, the continental geologists very na-
turally concluded that it was wanting in the English series, an
inference which has led to some erroneous generalisations.

The grounds on which this subdivision is proposed are the fol-
lowing : —

1 . Distinct mineralogical characters, in a constant position in the
series ; in which respects it is of the same value as most other geolo-
gical arrangements.

2. Agreement in this respect with the nearest portions of the cre-
taceous series in France.

3. Its position beneath the lowest portion of the series which is
to be found described in works on the subject.

4. A distinct and peculiar suite of organic remains. —
Ostrsea, n. s. common. Cardium hillanum.

Pholadomya neocomensis. subhillanum.

solenoides. Cucullsea raulini.

Corbula punctum. Modiola Archiaci.
Astarte Beaumonti. lanceolata.

' substriata. Trigonia scabra.

transversa. palmata ?

Thetis minor. ■ Fittoni.

Mr. A. Robertson on the Freshwater Fossils of Brora. 71

Pinna sulcifera. Terebratula biplicata.

Perna mulleti. elegans.

Gervillia anceps. sella.

aliformis. Auricula incrassata.

Avicula ? Natica.

Pholadomya Prevosti, Turritella laevigata.

rhomboidalis. Dupiniana.

Lima elegans ? Rostellaria ?

Pecten interstriatus. ?

Hinnites Leymerii. Nautilus pseudo-elegans.
Exogyra sinuata, var. N

subsinuata.

Ostrea Leymerii. Pycnodus

There is still direct evidence in the Isle of Portland that a part of
the south of England rose into dry land at the close of the oolitic
aera : and other considerations make it very probable that at that
time the extent of dry land in the northern latitudes was very con-
siderable. The range of the Neocomian deposits along the south of
Europe shows the amount of submersion, next after the oolitic epoch,
and we see in the Boulonnais, in the Pays de Bray, in the Paris
basin, Franch Cerate, Neufchatel, and part of Germany, how very
close the upper marine Neocomian beds approach to our own fresh-
water or tertiary Wealden : so that consistently with the views of
the continental geologists, we seem to have ascertained some inter-
esting points in the physical geography of a part of the surface of
the earth during the secondary period ; such as the direction from
which the waters of the vast Wealden stream flowed, and the line
where (approximately at least) they joined those of the sea. No
one who has either traced the cretaceous series in the range along
the southern portion of England, has seen it abroad, or studied the
numerous fossil remains which the formation contains, together with
their geographical range, can entertain the least doubt but that the
sea which deposited it was brought from the south northwards by a
gradual process of overlap. For this reason it is that the cretaceous
series of the continent, and of the south of Europe in particular, is so
much more fully developed than our own ; and it becomes of interest
to ascertain at what precise period it was that its waters reached our
latitudes ; in other words, how much of the series is represented here.
The groups of this country must cease to be the measure and type
of the cretaceous epoch, of which they only represent a part.

" Notice of the occurrence of Beds containing Freshwater Fossils
in the Oolitic Coal-field of Brora, Sutherlandshire." By Alexander
Robertson, Esq., F.G.S.

Among the reefs of shale and coal opposite the old salt-pans at
Brora, Mr. Robertson has discovered two beds abounding in Cyclas
and other freshwater fossils, approachable only at low water. The
rise of the tide on the occasion of his visit to the locality, prevented
a minute examination of their relations. Their position was however
satisfactorily made out, and is, in the descending order, as follows : —

a. Beds of calcareous sandstone, considered by Mr. Phillips to re-

72 Geological Society.

present the gray limestone of Cloughton and other localities in York-
shire.

b. Shale and coal, several feet.

c. Shale with fossils about an inch.

d. Shale and coal similar to the beds b, two or three feet.

e. Clay with fossils about thirteen inches.

f. Shale with a few plants.
The bed c has yielded, —

Fishes. — Scales of a species of Lcpidolus, strongly resembling L.
fimbriatus, Ag. Scale of Megalurus ?

Mollusca, Paludina, several new species. Cyclas, one or two new
species.

Crustacea. — Cypris, new species. Plant, obscure impressions.

From the bed e the following have been obtained : —

Fishes. — Scales of two or three species of Lepidotus. Teeth of
Acrodus minimus, Ag. ? Teeth of Hybodus minimus, Ag.

Mollusca. — Paludina, same species as in the upper bed. Two or
three species of Perna, some of which are probably new. Unto, one
new species. Cyclas numerous, new species chiefly belonging to
Lamarck's genus Cyrena*.

Crustacea. — Cypris, same species as in the upper bed.

Plants. — Minute fragments of carbonized wood.

Nearly the whole mass of both beds consists of fossils. No ma-
rine fossils (with the exception perhaps of the scales of Lepidotus)
are found in the upper bed, and it seems therefore to be properly a
freshwater deposit. The mixed nature of the fossils of the lower
one conclusively point out its estuary character.

" Observations on the occurrence of Freshwater Beds in the Ooli-
tic Deposits of Brora, Sutherlandshire ; and on the British Equiva-
lents of the Neocomian System of Foreign Geologists." By Rode-
rick Impey Murchison, Esq., F.G.S.

In this communication the author confirms the interesting disco-
very announced by Mr. Robertson in the preceding paper, and re-
marks, that as the reefs of rock exposed at low water at the mouth
of the river Brora unquestionably lie beneath the Oxford clay, and
are not far above the roof of the coal, there can be no doubt that the
beds containing the freshwater shells, being fairly intercalated with
the other strata, are thus inclosed in the heart of the oolitic series.
They had escaped the notice of Mr. Murchison, probably from ha-
ving been covered by sea sand at the time of his visit.

An examination of the freshwater specimens collected by Mr.
Murchison and Professor Sedgwick at Loch Staffin, in the Isle of
Skye, has identified the principal forms with Mr. Robertson's spe-
cimens from Brora, and has led the author to adopt a different view
respecting the position of the beds from which they were derived.

* Among the specimens sent to the Society by Mr. Robertson were se-
veral examples of Cyclas media, identical with the Wealden shell. The
Perna referred to is altogether new, and will probably form the type of a
genus, bearing a relation to Perna analogous with that which Dreissena
bears to Mylilus.

Mr. Murchison on the Freshwater Beds of Brora. 73

Instead of supposing that the oolitic series of the cliffs near Portree
was overlaid by a true equivalent of the Wealden*, the freshwater
beds of Skye will it is now believed be found, like those of Inver-
brora, to be interstratified with the middle oolite, a conclusion ren-
dered probable by the natural sections and form of the coast, and
by the circumstance that the fragments not found in situ which
contained freshwater shells were collected near the escarpment and
not on the dip of the oolitic strata. Mr. Murchison is inclined to
take a similar view of the freshwater deposits near Elgin, compared
by Mr. Malcolmson to the Purbeck beds of England.

The author remarks, that with the terrestrial evidences in the plants
of Portland, Scarborough, Stonesfield and Brora, we might naturally
expect at any day to hear of the associated lacustrine or river shells.
But Mr. Robertson's discovery further compels us to believe, that the
same species of freshwater shells prevailed, not only during the whole
of the Wealden epoch, but that they were in existence at periods
long antecedent, when the adjacent lands poured forth rivers into the
sea in which the middle and lower oolites were accumulated, and
thus we acquire a new element to enable us to reason upon the
former conditions of the surface.

The facts stated by Mr. Robertson tend to confirm the idea, that
the Wealden is more naturally connected with the Jurassic than
with the cretaceous system, and must also have an influence in de-
ciding that the Neocomian formation of foreign geologists ought not
to be placed on the parallel of the Wealden. Mr. Murchison has for
some years been of opinion that the Neocomian system is little more
than an equivalent of the lower greensand of British geologists, a
view which he upheld at the meeting of the Geological Society of
France at Boulogne in 1839, on the ground of the identity of their
stratigraphical relations and typical fossils. Further researches du-
ring last May along the coast of the Isle of Wight, in company with
Count Keyserling, led both that gentleman and the author to the
same conclusion. Among the numerous fossils they there collected
were many identical with, or analogous to, Neocomian species, par-
ticularly in that portion of the coast section so minutely described
by Dr. Fitton and Sir John Herschel, viz. between Black Gang
Chine and Atherfield rocks. Mr. Murchison observed that there
seemed to be a gradual zoological as well as lithological passage from
the Wealden beds below into the greensand and shales above them ;
for although the shale with Cypris occurs immediately beneath the
marine deposit of Atherfield rocks, as remarked by Dr. Fitton,
another band of flagstone with marine shells (Ostrea and Terebra-
tula) also occurs beneath these uppermost beds of Cypris. In the
still lower strata, however, we lose all traces of such marine alter-
nations, and the whole becomes one great freshwater deposit. A
similar phsenomenon is seen in the southern part of the section at
Red Cliff, extending into Sandown Bay, where beds with Cypris are
intercalated between oyster beds. These alternations are indeed
what we might expect to find, provided a former depression of the
* Geol. Trans, vol. ii. p. 366.

74 Geological Society : Mr. Lyell on the

surface had converted a lake into an estuary, and subsequently into
a marine bay. But notwithstanding the natural connexion be-
tween the Wealden and the lower greensand, it does not follow that
the two formations ought to be merged in one system or natural
series. Dr. Mantell as long ago as 1822 pointed out the analogy
between the animals of the Wealden and those of the Stonesfield
beds ; and more recently Professor Owen has carried it out much
further. Professor Agassiz has pronounced the Ichthyolites of the
cretaceous system to be entirely dissimilar from those of the Wealden.

Mr. Murchison inquires, where are we to draw the line of sepa-
ration which shall indicate precisely in our own country the base of
the Neocomian of foreign geologists, or in other words, the base of
the great continental cretaceous system ? On this point he remarks
that some small amount of compromise may eventually be found de-
sirable ; for whilst we have on the one hand full right to infer that
the larger portion of the Wealden must be classed in the oolitic
series, further inquiry may convince us that its uppermost part is of
the same age as the lowest Neocomian strata ; and thus we may
connect that portion of it with the cretaceous system. In the mean
time it is quite clear that a great part of the Neocomian is absolutely
the lower greensand itself. This view is confirmed by Count Key-
serling, who has identified fossils from the Neocomian strata of Kys-
lavodsk in the Caucasus, with specimens collected by him in com-
pany with Mr. Murchison in the lower greensand of the Isle of Wight.

April 26. — A paper was read " On the upright Fossil-trees found
at different levels in the Coal strata of Cumberland, Nova Scotia."
By Charles Lyell, Esq., F.G.S. &c.

The first notice of these fossil trees was published in 1829 by
Mr. Richard Brown, in Hali burton's ' Nova Scotia,' at which time
the erect trunks are described as extending through one bed of
sandstone, twelve feet thick. Their fossilization was attributed by
Mr. Brown to the inundation of the ground on which the forest
stood. Mr. Lyell in 1842 saw similar upright trees at more than
ten different levels, all placed at right angles to the planes of stratifi-
cation, which are inclined at an angle of 24° to the S.S.W. The
fossil trees extend over a space of from two to three miles from north
to south, and, acccording to Dr. Gesner, to more than twice that
distance from east to west. The containing strata resemble litho-
logically the English coal-measures, being composed of white and
brown sandstones, bituminous shales, and clay with ironstone. There
are about nineteen seams of coal, the most considerable being four feet
thick. The place where these are. best seen is called the South
Joggins, where the cliffs are from 150 to 200 feet high, forming the
southern shore of a branch of the Bay of Fundy, called Chignecto
Bay. The action of the tides, which rise sixty feet, exposes con-
tinually a fresh section, and every year different sets of trees are
seen in the face of the cliffs.

The beds with which the coal and erect trees arc associated are

* Abstracts of other papers by Mr. Lyell on the Geology of North
Am erica will be found in the preceding volume, p. 180.

upright Fossil Trees of Nova Scotia. 75

not interrupted by faults. They are more than 2000 feet thick, and
range for nearly two miles along the coast. Immediately below them
are blue grits used for grindstones, after which there is a break in
the section for three miles, when there appear near Minudie beds of
gypsum and limestone, and at that village a deep red sandstone, the
whole having the same southerly dip as the coal at the Joggins, and
being considered by Mr. Lyell as the older member of the carbo-
niferous series.

Above the coal-bearing beds, and stretching southwards for many
miles continuously along the shore, are grits and shales of prodigious
thickness, with coal-plants, but without vertical trees.

Mr. Lyell next describes in detail the position and structure of
the upright trees at the South Joggins. He states that no part of
the original tree is preserved except the bark, which is marked ex-
ternally with irregular longitudinal ridges and furrows, without any
leaf-scars, precisely resembling in this respect the vertical trees
found at Dixonfold on the Bolton Railway, described by Messrs.
Hawkshaw and Bowman. No trace of structure could be detected
in the internal cylinder of the fossil trunks, which are now filled
with sandstone and shale, through which fern-leaves and other plants
are scattered. Mr. Lyell saw seventeen vertical trees, varying in
height from six to twenty feet, and from fourteen inches to four
feet in diameter. The beds which inclose the fossil trees are usually
separated from each other by masses of shale and sandstone many
yards in thickness. The trunks of the trees, which are all broken
off abruptly at the top, extend through different strata, but were
never seen to penetrate a seam of coal, however thin. They all end
downwards either in beds of coal or shale, no instance occurring of
their termination in sandstone. Sometimes the strata of shale,
sandstone and clay, with which the fossil trunks have been filled,
are much more numerous than the beds which they traverse. In
one case nine distinct deposits were seen in the interior of a tree,
while only three occurred on the outside in the same vertical height.

Immediately above the uppermost coal-seams and vertical trees
are two strata, probably of freshwater origin, of black calcareo-
bituminous shale, chiefly made up of compressed shells of two
species of Modiola, and two kinds of Cypris.

Stigmarice are abundant in the clays and argillaceous sandstones ;
often with their leaves attached, and spreading regularly in all direc-
tions from the stem. The other plants dispersed through the shales
and sandstones bear a striking resemblance to those of the European
coal-fields. Among these are Pecopteris lonchitica, Neuropteris
Jlexuosa ?, Catamites camueformis, C. approximates, C. Steinhaueri,
C. nodosus, SigiUaria undulala, and another species.

The genera Lepidodendron and Sternbergia are also present.
The same plants occur at Pictou and at Sydney in Cape Breton, ac-
companied with Trigonocarpum, Aster ophyllites, Sphcenophyllum,
and other well-known coal fossils.

The author then gives a brief description of a bed of erect Ca-
tamites, first discovered by Mr. J. Dawson in the Pictou coal-field,

76 London Institution,

about 100 miles eastward of the Cumberland coal-measures before
described. They occur at Dickson's mills, \\ mile west of Pictou,
in a bed of sandstone about ten feet thick. They all terminate
downwards at the same level where the sandstone rests on subjacent
limestone ; but the tops are broken off at different heights, and
Mr. Dawson observed in the same bed a prostrate Lepidodendron,
with leaves and Lepidostrobi attached to its branches.

From the facts above enumerated, Mr. Lyell draws the following
conclusions : —

1 . That the erect position of the trees, and their perpendicularity
to the planes of stratification, imply that a thickness of several thou-
sand feet of coal strata, now uniformly inclined at an angle of 24°,
were deposited originally in a horizontal position.

2. There must have been repeated sinkings of the dry land to
allow of the growth of more than ten forests of fossil trees one above
the other, an inference which is borneoutbythe independent evidence
afforded by the Stignnaria, found intheunderclays beneath coal-seams
in Nova Scotia, as first noticed in South Wales by Mr. Logan.

3. The correspondence in general characters of the erect trees of
Nova Scotia with those found near Manchester, leads to the opinion
that this tribe of plants may have been enabled by the strength of its
large roots to withstand the power of waves and currents much more
effectually than the Lepidodendra and other coal plants more rarely
found in a perpendicular position.

Lastly, it has been objected, that if seams of pure coal were formed
on the ground where the vegetables grew, they would not bear so
precise a resemblance to ordinary subaqueous strata, but ought to
undulate like the present surface of the dry land. In answer to this
Mr. Lyell points to what were undoubtedly terrestrial surfaces at
the South Joggins, now represented by coal seams or layers of shale-
supporting erect trees, and yet these surfaces conform as correctly
to the general planes of stratification as those of any other strata.

He also shows that such an absence of superficial inequalities,
and such a parallelism of successive surfaces of dry land, ought to
be expected, according to the theory of repeated subsidence, be-
cause sedimentary deposition would continually exert its leveling
action on the district submerged.

LONDON INSTITUTION.
December 18, 1843. — Professor Grove on the Correlation of Phy-
sical Forces. Mr. Grove has just finished a course of six lectures
on the above subject, commenced November 13. The object of the
course has been to show that motion, chemical affinity, heat, light,
electricity and magnetism are all convertible affections of matter, —
that either being taken as an initial mode of force is able to produce
any of the others ; thus moving bodies may be made mediately or
immediately to produce heat, light, electricity, chemical affinity, or
magnetism. Matter affected by chemical affinity may be made to
produce motion, heat, light, electricity and magnetism, and so of the
rest.

Prof. Grove on the Correlation of Physical Forces. 77

In the first lecture on motion the following original view of the
production of heat was taken. If one body move against or strike
another it communicates its motion to the latter, and stops while the
latter takes up the original motion ; and moves, not indeed quite
equal in amount to the original moving body, because the air or
other surrounding medium is set in motion, and thus conveys away
some of the initial force : if the second body be retained, or not per-
mitted to move in the same direction, it may still move in a different
one. Take for example two wheels, the circumference of which touch
each other : if the one be made to revolve it communicates motion
to the other which revolves in a different direction ; if, however, the
second be forcibly restrained or prevented from carrying on the
motion of the first, heat is produced : thus, though the motion appa-
rently ceases, still the effect of the initial force is rendered evident
in another form. The same thing occurs if two bodies, moving in
contrary directions, meet each other ; they, to a certain extent, arrest
or stop each other's motion, but to this extent they also become
heated. In the case of dissimilar bodies impinging on each other
electricity is produced as well as heat, but the more there is of the
one the less there is of the other force ; and neither in this case nor
in any other will the forces produced, whatever be their character,
reproduce the full amount of the initial force : thus the heat pro-
duced by friction could never, if applied to boil water, work a steam-
engine which would produce an equal amount of motion on the same
quantity of matter as that which originally gave rise to the heat ;
though the force is not destroyed, it is dissipated or subdivided in
direction. These considerations lead to the conclusion that force,
like matter, cannot be annihilated, but may go on subdividing itself
or changing its form for ever. Want of space prevents our going
through the experimental proofs adduced by Mr. Grove to support
his views. In each lecture one of the above forces was taken as the
initial force or starting-point, and it was shown experimentally how
the others were produced by it.

The following is the order in which the subject was considered,
as stated in the syllabus printed for the members of the Institution
and other attendants of the lectures.

Lect. I. — Monday, November 13th, 1843. — Introduction — Force —
Usual definition — Matter — Attraction — 'Motion — its connexion with
Light, Heat, Chemical Affinity, Electricity, Magnetism. Lect. II. —
Chemical Affinity — Ultimate conceptions regarding it — Transferred
or acting through a chain of particles — its connexion with the other
modes of force. Lect. III. — Heat and Light — Expansion or mutual
recession of Molecules — propagation of heat and light — Theories —
Specific Heat — Thermography — Photography — Relation to the other
modes of force. Lect. IV. — Electricity — Application of the term to
very different phenomena — Franklinic — Voltaic — Theories — Objec-
tion to hypothesis of fluids — Regarded as a mode of force and con-
nected with the other forces. Lect. V. — Magnetism — viewed as
an absorption of force — operative when conjoined with motion —
Magneto-Electricity. — All moving bodies magnetic in proportion to

78 Intelligence and Miscellaneous Articles.

their electric conducting powers. Lect. VI. — December \&th. —
Union of forces in the phenomena of Geology and Physiology —
Theories of Causation — Ignorance of ultimate causation. Conclusion.

XII. Intelligence and Miscellaneous Articles.

PREPARATION OF HYPOSULPHITE OF SODA. BY M. WALCHNER.

THIS salt, according to M. Walchner, is readily prepared and in
large quantity by the following process : — dry crystallized carbon-
ate of soda perfectly and reduce it to fine powder ; mix one pound with
five ounces of sulphur, and heat the mixture gradually in a porcelain
vessel until the sulphur melts ; the agglutinated mass being kept hot
is to be stirred in order that every portion of it may come into con-
tact with the air ; in this case the sulphuret of sodium formed is con-
verted into sulphite of soda, by absorbing oxygen from the atmo-
sphere. This salt is to be dissolved in water, the filtered solution is
to have sulphur boiled in it, and the filtered liquor, which is nearly
colourless when much concentrated, yields very pure and fine cry-
stals of hyposulphite of soda in large quantity.

When the temperature is too rapidly raised a small quantity of
sulphur burns readily ; a portion of carbonate of soda then remains
unacted upon and destroys the purity of the crystals of hyposulphite
first obtained ; but it is easy to separate the impurity. — Journ. dePh.
et de Ch„ Octobre 1843.

ON THE ACTION OF CHLORIDES UPON PROTOCHLORIDE OF
MERCURY. BY M. MIALHE.

In vol. xxi. pp. 320 and 492 of the L. and E. Phil. Mag. S. 3 will be
found the results of M. Mialhe's experiments on the above subject,
and in vol. xxiii. p. 233 we gave the results of M. Larroque's expe-
riments on the same subject, and of the different conclusions at
which he had arrived from those maintained by M. Mialhe. M.
Mialhe, still retaining his opinions, has published some further re-
marks on the subject ; and on the opinions of M. Larroque he ob-
serves, that while M. Larroque admits that protochloride of mercury
is dissolved by the alkaline chlorides at common temperatures, he
denies that it is converted into bichloride, but is held in solution as
protochloride.

In support of his opinion M. Mialhe states an experiment which
positively determines that the mercury exhibited in this case by hy-
drosulphuric acid or the hydrosulphates, is not in the state of proto-
chloride. He observes that an excess of these reagents completely
redissolves the precipitate they occasion, which could not happen if
the salt were a protosalt.

In concluding his reply to M. Larroque, M. Mialhe states, — 1st.
That, contrary to the assertions of Hervy, MM. Caventou, Larroque,
&c, protochloride of mercury is partly converted into bichloride by
the influence of aerated alkaline chlorides, at common temperatures.
2nd. That the mercurial compound which is then formed is not,
however, identically the same as that which is produced when the

Meteorological Observations. 79

mixture is heated to ebullition : in the first case it is bichloride plus
binoxide of mercury, or an alkaline oxide which is formed without any
precipitation of metallic mercury ; whereas when heated, bichloride
of mercury only is produced, by the mere affinity of the alkaline chlo-
rides for bichloride of mercury, and in this latter case precipitation of
metallic mercury always occurs. 3rd. That it is not correct to say,
that when bichloride of mercury is formed in these various mixtures,
it is always easy to remove a portion of the bichloride by means of
aether ; this solvent being incapable of removing it when accompanied
with binoxide of mercury, as that is which the protochloride produces
by contact with cold solutions of the aerated alkaline chlorides. 4th.
That although the proportion of mercury dissolved is greater when
operating at common temperatures with hydrochlorate of ammonia
than with alkaline chlorides, it is nevertheless impossible to remove,
by means of aether, the mercurial compound dissolved in this case.
5th. That the alkaline chlorides do not dissolve calomel in the state
of protochloride, the compound dissolved having all the characters
of the bisalts of mercury, as incontestably shown by the action of
the alkaline cyanide, sulphuret and iodide employed in excess. —
Journ. de Ph. et de Ch., Octobre 1843.

METEOROLOGICAL OBSERVATIONS FOR NOVEMBER 1843.
Chiswick. — November 1. Hazy : foggy at night. 2. Hazy : rain. 3. Foggy:
very fine. 4, 5. Fine. 6. Overcast : rain. 7. Heavy rain : cloudy : clear.

8. Cloudy and fine : heavy rain : clear and frosty at night. 9. Frosty : clear.

10. Rain. 11, Fine: easterly haze : clear and frosty. 12. Cloudy and fine :
clear and frosty. 13. Sharp frost: fine: cloudy. 14. Hazy : rain. 15. Frosty :
very fine. 16. Clear and very fine. 17. Frosty: haze: heavy rain. 18. Fine.
19. Clear: boisterous at night, 20. Clear and windy. 21, Overcast: boisterous.

22. Hazy clouds : overcast : heavy rain. 23. Rain : clear and frosty at night.
24. Foggy : densely overcast: rain. 25. Hazy and drizzly. 26. Cloudy : boisterous
at night. 27. Squally : clear and fine. 28. Very fine. 29. Clear and very fine
throughout. 30. Sharp frost : hazy : drizzly. — Mean temperature of the month
09° above the average.

Boston. — Nov. 1. Cloudy, with rain. 2. Foggy: rain early a.m. 3.
Foggy. 4. Fine. 5. Cloudy. 6, 7. Rain : rain early a.m. 8, 9. Fine. 10.
Cloudy: rain early a.m. 11. Cloudy. 12, 13. Fine. 14. Cloudy : rain p.m.
15. Foggy: rain p.m. 16 — 18. Cloudy. 19. Fine: stormy night. 20. Stormy:
rain early a.m. 21. Cloudy : rain early a.m. 22. Stormy : rain a.m. and p.m.

23. Rain. 24. Fine. 25. Cloudy : rain p.m. 26. Cloudy. 27. Fine. 28.
Cloudy : rain p.m. 29,30. Fine.

Sandwick Manse, Orkney . — Nov. 1. Showers : clear : fine. 2. Clear : fine.
3. Cloudy. 4. Rain : cloudy. 5. Clear : clear and rain. 6. Showers : clear.
7. Showers. 8. Showers and hail. 9. Cloudy : cloudy and snow. 10. Damp.

11. Cloudy. 12. Rain. 13. Cloudy: showers and clear. 14. Bright: fine
and cloudy. 15. Rain: showers. 16. Cloudy. 17. Showers. 18. Cloudy:
clear. 19. Clear: showers: clear. 20. Rain. 21. Showers : cloudy. 22,23.
Cloudy : showers. 24. Showers : clear frost. 25. Fine : clear frost. 26. Damp :
fine : rain. 27. Rain : damp. 28. Damp : rain. 29. Showers : cloudy. 30,
Rain.

Applegarth Manse, Dumfries-shire. — Nov. 1. Frost : fine. 2. Fine. 3. Cloudy:
rain p.m. 4. Showers. 5. Fair. 6. Showers. 7. Rain early a.m. 8. Fair.

9. Fair till p.m. : wet. 10. Showers. 11. Fair and fine. 12. Dull and cloudy :
showers. 13. Dull and cloudy. 14. Fair. 15. Rain: frost a.m. 16. Fair:
frost a.m. 17,18. Hain. 19. Slight showers. 20. Showers. 21. Rain. 22.
Slight showers. 23. Frost. 24. Frost : thaw p.m. 25—28. Rain. 29. Fair,
30. Fog and rain p.m.

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THE
LONDON, EDINBURGH and DUBLIN

PHILOSOPHICAL MAGAZINE

AND

JOURNAL OF SCIENCE.

[THIRD SERIES.]

FEBRUARY 1844.

XIII. On the Undulatory Theory of Interference. By R.
Moon, M.A., Fellow of Queen's College, Cambridge, and of
the Cambridge Philosophical Society*.

TN the following paper I shall endeavour to give a rationale
of the theory of interferences as explained upon undulatory
principles. I conceive that this is still a desideratum, for
though by adopting the hypothesis of secondary waves as a
basis for calculation, Fresnel has shown that a sufficiently
probable explanation may be given of that class of phaeno-
mena, it cannot be pretended that that explanation presents
to the mind any clear idea of the mode in which the pheno-
mena are actually brought about. Thus if we consider the
case of a succession of spherical waves emanating from the
same centre and incident upon an opake body, it is a natural
inquiry what becomes of each wave after diffraction. Can it
be possible that all trace is lost of the system of similar con-
centric waves? and if not, what is the nature of the modifica-
tions of those waves individually, and of their relations with
each other?

It is in this point of view, in which the received explanation
affords no light, that I propose to attempt the elucidation of
the subject; and if the considerations I am about to submit
involve nothing either very new or very striking, they may
nevertheless be found to lead to conclusions equally simple
and important.

Suppose then we have a single spherical wave diffracted at

the edge of an opake object of indefinite extent, and suppose

the wave to consist of a simple condensation followed by a

rarefaction, it is obvious that immediately after passing the

* Communicated by the Author.

Phil. Mag. S. 3. Vol. 24. No. 157. Feb. 1844. G

82 Mr. R. Moon on the XJndulatory Theory of Interference.

edge of the object the condensed portion of the wave will tend
to relieve itself laterally by an efflux of the particles it con-
tains into the geometrical shadow, where the density (that of
equilibrium) is less than its own, and thus we shall have within
the shadow a line of condensation in prolongation of the con-
densed portion of the wave. It is also clear that the portion
of aether within the geometrical shadow contiguous to the rare-
fied part of the wave will tend to flow into that part (where
the density is less than that of equilibrium), and thus we shall
have within the shadow a rarefaction in prolongation of the
rarefied part of the wave, and lying immediately behind the
prolonged condensation ; or, in other words, the wave will ex-
tend within the shadow.

Of the form of this extended portion of the wave it is beside
my present purpose to speak, but it should be observed, that
as the wave thus prolonged must evidently be continuous, a
variation from the spherical form must necessarily take place
in that portion of the wave which remains without the shadow,
since otherwise, in the case of a series of concentric spherical
waves, it would be impossible that interference should occur ;
for each wave being continuous, it can only be by the inter-
section of two consecutive waves that interference can take
place. But here we are met by a great and what may appear
to some an insurmountable objection, for no such change of
form as that we have spoken of can take place, except from a
change of velocity in that portion of the wave; and it lias
never been disputed that in the free aether all waves are pro-
pagated with the same uniform velocity. In reference to this
point we would observe, that the present is a case of wave mo-
tion altogether peculiar, and one of which no example bearing
the smallest resemblance to it has been hitherto subjected to
investigation. All cases of wave motion hitherto investigated
algebraically resolve themselves into the simple case of the
propagation in the direction of the axis of a cylindrical tube
of a wave whose front is perpendicular to the edge. The
motion of a wave after diffraction may be assimilated to motion
along a tube, of which part of the side has been cut away ; this
peculiar kind of wave motion, as we have said, has not hitherto
been subjected to calculation, and in fact it seems to baffle all
attempts of the kind. It must therefore be by a general kind
of reasoning on simple mathematical principles, that any know-
ledge respecting this branch of dynamics can be obtained.
And upon such principles it would, we apprehend, be difficult
to prove it impossible, or in fact to make it appear very im-
probable, that the wave should propagate itself with a differ-
ent velocity after its lateral extension from what it would have

Mr. R. Moon on the Undnlatory Theory of Interference. 83

done had it not been diffracted. Hence it can only be as a
physical fact, not as a dynamical principle, that this objection
can be urged. And taken in this point of view it can simply
amount to this, that in vacuo all spherical waves are originally
propagated with the same velocity, and that when unobstructed
such velocity will remain invariable, both which propositions
we admit in their fullest extent ; but this does not imply that
every possible variety of wave motion must be propagated with
uniform velocity (which in fact is perfectly incredible), and
until some proof to the contrary be given we shall consider
ourselves justified in assuming the case of broken or diffracted
waves to be an exception to the principle.

The possibility of a change of form being once admitted,
it is easy to imagine how waves of the same length, but which
differ in the relative condensation and rarefaction of their
several parts, may effect such change with different degrees of
rapidity ; for the change of form depends entirely on the late-
ral extension of the waves, which in its turn must depend on
the degree of condensation and rarefaction of their different
parts.

If, then, we have two such waves propagated at a short in-
terval from each other, the first of which is more retarded by
the diffraction than the second, they will ultimately intersect,
and so (the waves being nearly parallel) interference will be
produced. It is true that the intersection must take place at
a finite distance from the edge of the diffracting body, but it
is easy to suppose that this may be so small as to be inappre-
ciable by our senses. It is also evident that, as the waves will
continue to change their forms as they advance beyond the
object, the locus of their intersections will not be a straight
line, but will tend continually to diverge from the geometrical
shadow, and this divergence will constantly diminish as the
waves advance (since the relative change of the two fronts
with respect to each other must constantly diminish), and will
ultimately become insensible. Thus the line of interference
will approximate to the hyperbolic form.

If the first two waves are followed by a third at about the
same interval from the second as the second is from the first,
and nearly the same relation obtain between the second and
third as between the first and second, the locus of the inter-
section of the second and third will nearly coincide with the
locus of intersection of the first and second, but the intersec-
tion of the first and third will take a different path, and thus a
second line of interference will occur. Also, this second line
of interference will lie without the first, for they must both
have the same sensible origin ; and as the relative change of

G2

84 Mr. R. Moon on the Undulatory Theory of Interference.

form of the first and third must be more rapid than in any two
immediately consecutive waves, it follows that the divergence
from the geometrical shadow must be greater in the former
case than in the latter. Other lines of interference occurring
in the same manner, we are led to the conclusion that light of
one colour, as it actually presents itself to our observation, is
not, in fact, homogeneous, but consists of the same constantly
recurring series of waves of the same length, but otherwise so
far differing from each other that each individual of the series
changes its form after diffraction less rapidly than its imme-
diate predecessor*.

The explanation upon the above principles of the fringes
within the shadow of a narrow body illuminated from a single
point is so obvious as to require no particular comment.

Recurring to our original example, it remains to say a few
words on the effect produced by intercepting the diffracted
rays by a transparent plate. It is well known that the velo-
city of the wave is retarded in traversing the transparent me-
dium, and it seems very natural to suppose that the same
thing should obtain with reference to the lateral extension of
the wave after diffraction. Now if the lateral extension were
retarded, the relative change of form of the consecutive waves
would likewise be retarded ; and by necessary consequence
the divergence of the line of interference from the geometrical
shadow would be diminished, or in other words, "the fringes
will move within the shadow." Also, as the relative change
of form takes place more slowly in the fixed medium, it is clear
that the interposition of the transparent plate must produce the
same effect as if the screen op which the diffracted light is re-
ceived were removed to a distance from the diffracting body ;
that is, the fringes would become broader and more faint, and
gradually overlapping each other would ultimately disappear
altogether.

The principles above laid down, if correct, may be applied
to explain all the ordinary phaenomena of interference. We
shall merely observe, in conclusion, that the resolution of light
of one colour into waves of different diffrangibility, which we
have thus endeavoured to establish, may be subjected to the
same test as the Newtonian resolution of the solar ray into
rays of various colours. To ascertain whether diffracted rays
are further diffrangible, would require experiments of great
delicacy, but may not be impossible.

* If the velocity were supposed to increase instead of diminishing after
the diffraction, each succeeding wave must change its form more rapidly
than the one preceding it.

[ 85 ]

XIV. Differential Equations of the Moon's Motion.
By the Rev. Brice Bronwin*.

TF the moon's coordinates were expressed in terms of the
true elliptic longitude instead of the mean, it seems very
probable, if not quite certain, that there would be fewer equa-
tions. Their development would also be easier. These consi-
derations have led me to seek suitable formulae for the purpose,
in which I think I have been successful. The object of this
paper is to exhibit them.

Let ft =5 m + 7n', the sum of the masses of the moon and
sun, x and y the rectangular coordinates of the former on
the plane of her orbit, x', y' and 2/ those of the latter,

r = (xz + y ) i r — (xu + yli + * ) » R = — 5 — — /§ — ?-JL-L

m'

The equations of motion are

{r12 - 2 (x x' + y y') + r2}*

(fix ■ ux - dR „ d?y - ay dR
dr r* dx dt2 r3 dy

From these we easily derive
dx1 + dy2

dt2

_^+ii + 2 fdR = 0)
r a J

,D dR . . dR . dR < . dR ,

rfx rfy dr dv .

V being the moon's true longitude. Multiplying the first of
the above by x, the second by y, and adding them to the third,
we have

yyyfft' " * . * , P_0

„ tfR , rfR rt /» ■ </R „ /»,„

P = x-t— + y-= |-2/rfR=r— + 2 / dR.

dx dy J dr J

Similarly, we find

xdy — y dx ,'.'A „ 0dv , „

Now let g = rad. vect. y = long, in the elliptic or undis-
turbed orbit. These are given by the equations

whence results

* Communicated by the Authoi .

Make

86 The Rev. Brice Bron win's Differential Equations
i ^(g2) _ Jt + JL * o.

2 c?/2 g a0

? r = g + _p, and to abridge g = /x( J; for « and

a0, A and h0 may not be respectively equal, but may differ by
quantities of the order of the disturbing force. This value of

j ^2 /r2\ „ „

r being substituted in — — j-~ — + — + P = 0, making

djp _ dp dv _ h0 dp d*p _ h^ d?p 2h0dgdp
~dt~~dvTt~Y' J*' lH*~~gT~dv* ~~f~dtTv

or making v the independent variable ; in virtue of the assumed

equations we find

■&+p + h<P + ,) + r,-3ir+ a.

f,%P +pJ hJ^v + «c. —u.

"0 n0 % n0 5

Or if — = u ;
?

d*/> 1 /T1 . 1

i?+p ■

QluA v ' u dv \ dv/

(1.)

0

V 1 + up

The two last terms are of the order of the square of the
disturbing force. There will be a term of the form A cos (»— it)
arising from the disturbing force, and the quantity e or a is to
be so determined as to take it away.

The equation r2 dv — dt (k — Q) will become by this sub-
stitution

dv(h-Q) . „ s-i ( h 1 rd^dv\,n\

dv = mtzsr** +up) ■ U -gj-.ii.?} (2°

From this we shall find v = bv +f{v), b being a constant,
andy'(v) a function periodic of v; and we shall have {b — ■ 1) v
for the progression of the apse. We might have supposed the

central force — s H — *• instead of -h>, and have assumed —^
Ql oA p2 dt1

h 2 — <?
^—3 1 — 2" = 0j gQ d v = hQ d t, and have found p = v

+ y (v) » Dut I think the development will be more simple with
the assumption above made.

To find the latitude, let s = sin. lat., i= inclination, 3= long,
of the node on the plane of the orbit, having a fixed origin on

of the Moon's Motion. 87

that plane. Then s — sin i sin (v — 3) = x sin t; — A cos i;.
We have by known formulae,

of x cos2 i d R

dx _

d7 ~~

cos2 i rf R

«?/ " adv dx9
r -r-

fore

rfx_ g4cos2/ dR

rfv~,2 2dv dxf

n° r J7

dx

dv ~~

g4cos2? e?R
, 2 2rfw dx'

n° 1 Tv

These formulae cannot be investigated here, they are found
on the assumption that -j-dx + -z-dx = 0; consequently -j-

, . . .dv Ad?& d& , ... .d2v

— (xcosu + Asm v)-r-9 and -7-3 -f- -j-zS = (xcosv + Asmo-7-3

dv dv1 dv2 v 'dv1

( dx . d x\ dv rn\ - l .Pdv* .

•+■ I cos v —r- + sin 0 -7- I -j-. 1 his becomes, it -r-^ aA + 4,
V dv dv / dv dv2

where A is constant, <p periodic,

d2 s d* v

srs + As = (x cos v + A sin v) -r-s — s
dv1 v • dvz

g4cos2z / dR . dR\

+ V^vcos^~s,n^

* • • (3.)

All the terms of the second member of this are of the order of

the disturbing force.

For correcting the values of the elements x and A, we have

ds ds

dv dv .

x = 5 sin v + -7— cos v, A = — s cos v + -7- sin v,
dv dv

dv dv

When we know the parts of s and v depending on the first

power of the disturbing force, we can find those of x and A

depending on the same by taking the finite variation of the

preceding equations ; and so on for the higher powers of that

force. This method may be employed for correcting the value

of R when we do not wish to find x and A separately. I have

employed x and A in preference to the elements i and 3, but

am not quite sure that it is better to do so.

To find the reduction to the fixed plane, let © be the long.

of the node on this plane, vx the long, on it, and make v — 3

= Vl _ © + A, or A = (v — S) — (», — ©). Then, if $

= lat. sin A = sin (v — •&) cos {vx — %) — cos (v — S) sin^ — ©)

sin2 -|- sin 2 (v — ■&)

= tan — tan 4> cos (v — •&) = } and A sb'

2 v ' cos<$

88 The Rev. Brice Bron win's Differential Equations

= sin2 ~ sin2(z; - S) (i + |- sin2 <J>) = sin2 -|Yl + -j-sin2 A

sin 2 (w — S) — — sin2 ~- sin2 i sin 4 (u— S) = sin2-^- ( 1 + sin2-^- )

1 . i

sin 2 (v — d) — sin4 — sin 4 (t> — •&), neglecting quantities

that are insensible. Make ty = v + ev, 0 = .&+ev, ei> being
the regression of the node, and

M = sin24-(l +sin2-M sin 2(4/- 0)--^sin44-sin4(4/-0).

Let M0 be the value of M when i and 0 are changed into i0
and 0O, these quantities denoting the constant parts of i and 6.

And let A M0 = I ( ■ — rfH — =*■ rf $) » where 4> is regarded

as constant both in the differentiation and integration. This
will be the part of M depending on the variable parts of i and
$ ; to which must be added the correction at the origin, or
i

J-

Sill" —

2 / -rf$ = O. Then the reduction = Mn+AMn + 0.

<s cos i

We must put for di, dQ, and d$ their known values. Such
equations in A M0 -f O as have like equations in v should be
put to the value of v; the remainder, if any, with those of M0
must be separately tabulated.

The coordinates of the disturbing body will be easily ex-
pressed in terms of v. Thus

n t + s = v + Ej sin (v — w) + E2 sin 2 (v — ir) + .

Or if — = m.

n

«' t + m s — m v + m Ej sin (v — it) +;
n' t + e' = m v + ta + m Et sin (v — n) + ,
where w = e' — m i. By this value of »' t + r we can express

7J, or 7/' = — , and v', the elliptic rad. vect. and long, of the

disturbing body in terms of v.

We must not make me = s', or w = 0, as has always been
done in the lunar theory, unless we afterwards expel m v by
restoring v', when -sr will vanish with it.

But I should prefer expressing u' and v' in terms of n' t + e';

or rather I would retain v', and express v! = -,-, by means of

v\ and integrate in the manner M. Hansen has done in his
Perturbation of Comets. Thus in an abridged form we have

of the Moon's Motion. 89

4 1 + e' = i +/(v') = m v + is + w/(v), "1
^V{1 +/'(vO} = rorfv{l +/'(v)}, h • (A.)
or dv1 =zmdv {1 +fl(ylv')} J

Then integrating by parts,

f:

d v sin (* v -f z7 v' + /3) = r cos (i v 4- i' v' + /3)

— -i- -Tdy'sm (ii + i' J + /3),

/■

</ v cos (* v 4- £' v' + /3) = -r- sin (/ v + **' i/ + /3)

— 4- /d v' cos (t v + *7 v' + |8).

Put for e? v' its value given by (A.), reduce and integrate again
by parts ; and so on till the new terms become so small that
they may be neglected.

To integrate (1 .) make p = S A . „ cos (/ v + i' v' + /3) ; then

g= -2A. r (i + ^v)5 cos (,' , + / i + f)
d2v'

But r1 (PS + 2dr'dv' = 0, or u1 d2 v' - c2dn' dv' = 0, and
d2v' = j — - = dv'^fz^'). We can therefore eliminate

both dv' and e?2v'; and after the necessary reductions have
been made, it may be convenient to put all the terms after the
first with those which arise from the disturbing force. Thus
all the integrations required can be performed, and if there be
more labour in the integrations, there will be less in the pre-
vious developments.

Such is a brief outline of the method 1 would propose for
determining the moon's coordinates. It is easier and requires
less labour than the old method ; certainly it would require
very much less than M. Hansen's theory, which is far more
laborious than the common method. But general formulae
should be constructed for the determination of the coefficients
in the development of the disturbing force after the manner
of that author. I may add that it may be applied also to the
planets.

Gunthwaite Hall, near Barnsley,
November 25th, 1843.

[ 90 ]

XV. Remarks upon the Theory of' Reciprocal Dependence in
the Animal and Vegetable Creations, as regards its bearing
upon Pala 'ontology. By Herbert Spencer'*,

TPOM perusing an article which some time since appeared
*-^ in the Philosophical Magazine explanatory of M. Dumas'
views respecting the peculiar relationship that exists between
plants and animals f, in so far as their action upon the atmo-
sphere is concerned, it occurred to me that the doctrine there
set forth involved an entirely new and very beautiful explanation
of the proximate causes of progressive development; and as the
idea does not seem to have been yet started, perhaps I may be
allowed to make your Journal the medium for its publication.

In unfolding the several results of the theory and exhibiting
its application in the solution of natural phaenomena, M.
Dumas adverts to the fact, that not only do the organisms of
the vegetable kingdom decompose the carbonic acid which
has been thrown into the atmosphere by animals, but that
they likewise serve for the removal of those extraneous sup-
plies of the same gas that are being continually poured into it
through volcanos, calcareous springs, fissures, and other such
channels. It is to the corollary deducible from this proposi-
tion, respecting the alterations that have taken place in the
composition of that atmosphere, that attention is requested.

If it had been found that during the past epochs of the
world's existence animals had always borne such a proportion
to plants as to ensure the combustion of the whole of the
carbon assimilated by them from the air, or in other words,
if the carbon -reducing class had always been exactly balanced
by the carbon-consuming class, it would then follow, that as
the gas decomposed in the one case was wholly recomposed in
the other, the only change that could have taken place in the
character of the atmosphere would have been a deterioration
resulting from the continual influx of carbonic acid from the
above-mentioned sources. Such, however, were not the con-
ditions of the case, for it is manifest, not only from the nature
of existing arrangements, but likewise from the records of the
world's history, that the vegetable kingdom has always had
such a preponderance as to accumulate a much larger supply
of carbon than could be consumed by animals. This was
especially the fact in the earlier seras. During those vast periods
that expired before the appearance of mammalia, and whilst
animate life was chiefly confined to rivers and seas, nearly the
whole of the immense masses of vegetation that then covered
the land, apparently with a much more luxuriant growth than

* Communicated by the Author. f Phil. Mag. S. 3. vol. xix. p. 337-

On the Reciprocal Dependence of Animals and Vegetables. 91

now, must have lived and died untouched by quadrupeds ; and
even though a certain portion of the carbon taken by them
from the atmosphere was again restored to it in the process
of decomposition, by far the greater bulk seems to have re-
mained in its uncombined form. Even after the creation of
the higher orders of vertebra ta, when the forests were inha-
bited by the Mylodon with its congeners, and subsequently by
the elephant and others of the Pachydermata, it cannot be sup-
posed that there was ever by their instrumentality an equili-
brium produced between those antagonist agencies — the vege-
table and animal creations. For although herds of such crea-
tures would doubtless commit extensive ravages upon the ve-
getation amid which they existed, it must be remembered that
they could only consume the young and comparatively suc-
culent portions of the trees upon which they fed, whilst the
whole of the carbon contained in the trunks and older branches
would remain untouched. That the same preponderance in
the assimilative power of the vegetable organisms over the
consuming power of the animal ones exists at the present day
is abundantly evident.

The fact of there having been a larger abstraction of carbon
from the atmosphere by the decomposition of its carbonic acid
gas than has ever been returned to it, will, however, be most
distinctly proved by a reference to purely geological data.
The vast accumulations of carbonaceous matter contained in
the numerous coal basins distributed over the surface of the
globe — the large proportion of bitumen existing in many of
the secondary deposits, to say nothing of the uncombined
carbon which must be diffused through a great part of the
strata composing the earth's crust, bear palpable witness to
the truth of the position. All such combustible material has
been originally derived from the air, and the fact of its re-
maining to the present day unoxidized and bidding fair to con-
tinue in the same condition (setting aside human agency) for
an indefinite period, strongly favours the conclusion that the
carbon of which it is composed has been permanently reduced
from the gaseous combination in which it previously appeared.

If then it be conceded that the carbonic acid which during
past teras escaped out of the earth has been continually under-
going the process of de-carbonization, it follows as an appa-
rently legitimate consequence, that its remaining constituent,
the oxygen, being thus constantly liberated and effused into
the atmosphere, now exists in that medium in a larger propor-
tion than it originally did, and that it has from the com-
mencement of vegetable life to the present day been ever on
the increase.

92 Mr. Herbert Spencer on the Reciprocal Dependence

To this inference there may, however, be raised objections.
It will possibly be said that the carbonic acid that in time past
issued by various channels out of the earth arose from the slow
combustion of carbonaceous deposits produced in the same
way as those now existing ; that the continuance of the like
phenomenon in our own day is due to the gradual destruction
of the same material, and that the strata of our coal-fields are
fated to undergo, by some future volcanic agency, a similar
revolution, and have their carbon once more sent into the air
in company with oxygen. Or it might perhaps be argued
that the oxygen set free by the instrumentality of plants has
entered into combination with some other element in place of
the carbon with which it was associated, and has thus been
again abstracted from the air as fast as it was added to it.

The first of these objections is plausible, in so far as the
possibility of such an arrangement is concerned, though it
does not appear to be countenanced by facts. Neither the
positions usually occupied by volcanos, nor the phenomena
attending their eruptions, seem to indicate that the carbonic
acid they evolve proceeds directly from the combustion of
carbonaceous matter. They rather imply that it has been
driven off from its combinations by heat or chemical affinity.
In the cases of calcareous springs it would also appear that
the gas liberated by them had been previously in connexion
with an earth, it may be for an indeterminate period. More-
over it should be borne in mind, that the ultimate tendency of
all chemical changes taking place in the interior of the globe
must be to oxidize the most combustible elements; and since
the greater part of the abundant metallic bases have a stronger
affinity for oxygen than carbon has, its continual de- oxidation
would result, rather than any action of the opposite character.
But even admitting the existence of some play of affinities by
which the carbonaceous matter deposited in the course of one
sera is transformed into carbonic acid and given back to the
atmosphere during another, there is still a link wanting to
complete the chain of this circulating system; for it is clear
that the oxygen which accompanies the carbon in each of its
re-appearances above ground has been derived from some in-
ternal source, and when it has once issued into the air and
been deprived of its carbon it has no visible means of regain-
ing its previous condition, and must consequently remain in
the air. On this assumption, therefore, we are still brought
in a great degree to the same conclusion. Here indeed the
second objection may perhaps be brought in aid of the first,
and in such case it would be said that the oxygen after being
liberated is again absorbed by other agencies and ultimately

of Animals and Vegetables, as bearing on Palaeontology. 93

carried down once more into the interior. This is however
rather a groundless supposition, there being no apparent mode
in which such process could be carried on, seeing that the sur-
face of the earth is already oxidized, and, as far as we can judge,
has always been so.

Assuming then that the proposed theory, supported as it is
by the fact that the constituents of the atmosphere are not in
atomic proportions, and borne out likewise by the foregoing ar-
guments, is correct, let us mark the inferences that may be
drawn respecting the effects produced upon the organic crea-
tion.

Superior orders of beings are strongly distinguished from
inferior ones by the warmth of their blood. A low organiza-
tion is uniformly accompanied by a low temperature, and in
ascending the scale of creation we find that, setting aside par-
tial irregularities, one of the most notable circumstances is the
increase of heat. It has been further shown, by modern dis-
coveries, that such augmentation of temperature is the direct
result of a greater consumption of oxygen; and it would ap-
pear that a quick combustion of carbonaceous matter through
the medium of the lungs was the one essential condition to
the maintenance of that high degree of vitality and nervous
energy without which exalted psychical or physical endowments
cannot exist.

Coupling this circumstance with the theory of a continual
increase in the amount of atmospherical oxygen, we are natu-
rally led to the conclusion that there must of necessity have
been a gradual change in the character of the animate crea-
tion. If a rapid oxidation of the blood is accompanied by a
higher heat and a more perfect mental and bodily develop-
ment, and if in consequence of an alteration in the composi-
tion of the air greater facilities for such oxidation are afforded,
it may be reasonably inferred that there has been a corre-
sponding advancement in the temperature and organization of
the world's inhabitants.

Now this deduction of abstract reasoning we know to be in
exact accordance with geological observations. An inspection
of the records of creation demonstrates that such change has
taken place, and although remains have from time to time been
found which prove that beings of an advanced development
existed at an earlier period than was previously supposed, still
the broad fact is not by any means invalidated. A retrospec-
tive view of the various phases of animal life, tracing it through
the extinct orders of mammalia, saurians, fishes, Crustacea,
radiata, zoophytes, &c, shows distinctly that whatever may
have been the oscillations and irregularities produced by inci-

94 Prof. Challis on a particular case of the

dental causes, the average aspect nevertheless indicates the
law of change alluded to, seeing that there appears to have
been an aera in which the earth was occupied exclusively by
cold-blooded creatures requiring but little oxygen ; that it was
subsequently inhabited by animals of superior organization
consuming more oxygen, and that there has since been a con-
tinual increase of the hot-blooded tribes and an apparent di-
minution of the cold-blooded ones.

Bearing in mind therefore the undoubted relationship that
exists between the consumption of oxygen on the one hand
and the degree of vitality and height of organization on the
other, it would appear extremely probable that there is some
connexion between the supposed change in the vital medium,
and the increased intensity of life and superiority of construc-
tion that has accompanied it. Whether the alteration that
has taken place in the constitution of the atmosphere is to be
looked upon as the cause of this gradual development of or-
ganic existence, or whether it is to be regarded as an arrange-
ment intended to prepare the earth for the reception of more
perfect creatures, are points which need not now be entered
upon. The question at present to be determined is, whether
the alleged improvement in the composition of the air has
really happened, and if so, whether that improvement has had
anything to do with the changes that have taken place in the
characteristics of the earth's inhabitants.

[*** We have inserted the foregoing communication because the inquiry
to which it relates is one of extreme interest, and our correspondent's rea-
soning may excite attention to the subject; but we doubt whether his
inferences are warranted by the known facts of Chemistry and Palaeon-
tology : we fear that his generalizations are at least premature. — Edit.]

XVI. On a particular case of the Application of Criteria of
Integr ability. By the Rev. J. Challis, M.A., Plumian
Professor of Astronomy in the University of Cambridge*.

TITHENEVER the differential expression P d x 4- Qdy

* " is the differential of some function (u) of the variables

x and y, P and Q are respectively equal to the partial differ-

. , ^ . du . du TT dP d* u ,

ential coefficients -=— and -1—. Hence -*— = -3 — 5—, and
d x dy dy dy d x

d Q d2 u XT . d* u , d*u . . . ,

-r? =a -. ^-. Now since -. — t— alK» 1 — -7- are identical

d x dx dy dy dx d x dy

quantities, the order of differentiation being of no consequence,

it follows that -r— and *s — are also identical. This is the sole
dy d x

* Communicated by the Author.

Application of Criteria of Integr ability. 95

criterion of integrability of a differential expression of two va-
riables. Besides the variables x and y, P and Q may contain
quantities unaffected by the sign of differentiation, and depend
for their values on the values assigned to these quantities.
Let us suppose as a particular case that P = 0 and Q = 0,

we shall then have -j— = 0 and -= — = 0, and the equation

dP dQ . ... .„,r™ -t

-j— = -j- ; is numerically satisfied, lne question I propose

to consider is, whether because this equation is thus satisfied,
V dx + Q dy is necessarily an exact differential when P = 0
and Q = 0.

Very simple considerations will enable us to answer this
question. We have seen above that the only condition of in-
tegrability is, that -z — and -j— ' be identical quantities. In
every case, therefore, the ratio of these quantities must be a
ratio of equality. But when -v— = 0 and -f — = 0, that ratio

is expressed by a vanishing fraction — , which is not necessa-
rily equal to unity. Consequently P d x + Q dy is not ne-
cessarily an exact differential when P = 0 and Q = 0.

The above reasoning readily suggests the process to be fol-
lowed for determining in any particular instance in which
P = 0 and Q = 0, whether P dx -f Q dy may be regarded as

an exact differential. Let the given expression be a (e — 1 )ydx
+ btxdy. Then P = a (/ - l)y, Q = btx, Sl-i «(/-l),

dQ . . . , . ad? A dQ. ale*- 1) 1Pj n

-5-2 = bt, and the ratio of -r— to ~ is - v . — '-. If t = 0,
dx dy dx bt

each of the quantities P, Q, — r-, -7- vanishes, and the ratio

1 dy dx

of -y— to -j — becomes — . But the real value obtained by
dy dx 0 '

the usual rule for finding the values of vanishing fractions is
-T-. As this quantity is not equal to unity unless a = b, the

expression a (e — \)y d x + btxdy cannot be considered an
exact differential when t — 0, unless a — b.

Analogous reasoning may be employed to show that P dx
+ Qdy + 1Hdz\s not necessarily an exact differential when
P = 0, Q = 0, and R = 0.

96 Mr. Hunt on the Itifluence of Light on Plants.

In the Mecanique Anatytique (part 2. sect. xi. art. 18) the
following sentence occurs: — " Lorsque le mouvement com-
mence du repos, on a alors p = 0, q = 0, r = 0, lorsque t = 0,
done p d x + qdy + rdz sera integrable pour ce moment."
The inference in the last clause evidently rests on the ana-
lytical theorem, that p d x + q dy + r dz may be considered
an exact differential whenever p = 0, q = 0, and r = 0, which
I have just shown to be untrue. The assertion of Lagrange
has been adopted by subsequent writers, and has occupied a
very important place in analytical hydrodynamics, the manner
of treating a large class of problems entirely depending on the
assumption of its truth. It is remarkable that so unfounded
a theorem should have remained so long unquestioned. The
omission of it in the last edition of Poisson's Mecanique is
perhaps an evidence that that author considered it incapable
of proof. The only attempt at a proof that I have met with
occurs in the Cambridge Philosophical Transactions (vol. vii.
part 3. p. 462), where it is asserted that when u = 0, v ;= 0,
and to = 0 for a given value of t (for instance t = 0), the ex-
pression u d x + v dy + to dz " may be regarded as a com-
plete differential with respect of x, y, z, of an arbitrary func-
tion of t." To this I answer, that since u, v and to each
vanish when t = 0, we may assume that u dx + v dy + ivdz

= f (U d x + V dy -f W dz), the quantity in brackets not
vanishing when / = 0. If now for / = 0 u d x + v dy + to d z
may be regarded as a complete differential with respect to .r,
y and z of a function of t only, in the same case U d x -f- V dy
+ W d z may also be regarded as such a differential. But
the latter quantity does not vanish when t = 0 ; which is
absurd. The argument of this writer consequently rests on a
false assertion.

I think I have now said enough to show that no confidence

whatever can be placed in any l'esearches in hydrodynamics

which depend on the assumption that u d x + v dy -f to d z is

always an exact differential when the motion begins from rest.

Cambridge Observatory, Dec. 18, 1843.

XVII. On the Itifluence of Light on Plants. By Robert
Hunt, Secretary to the Royal Cornwall Polytechnic Society.

To Richard Taylor, Esq.
Dear Sir,

IN the Philosophical Magazine for January is a communi-
cation from Dr. D. P. Gardner on the influence of Light
on Plants, in which he states that in 1840 I published "the
most decided results to the effect, that blue light alone causes

Mr. Hunt on the Influence of Light on Plants. 97

the green colour of plants." It will be seen, on referring to
that communication (Phil. Mag., April 1840, p. 272), or to
my paper in the Report of the British Association for 1842,
on the same subject, that I have never yet dealt decidedly with
the question of the production of chlorophyl. It is true I have
stated that plants growing under green media were etiolated,
that under " the yellow solution they were less pale than those
which had grown in green light" that under red media they
grew " of an unhealthy colour" and " that under the blue fluid
there was a crop of cress of as bright a green as any which
grew in full light." From these results we might infer that
the so-called " chemical rays " were the most active in produ-
cing this green colouring matter, and I shall require a far
more extensive series of experiments than those of Dr. Gard-
ner before I am convinced that the mean luminous ray of the
spectrum is the most actively concerned in the production of
chlorophyl ; at the same time I have never pronounced any
decided opinion on this matter.

On the question of the movements of plants towards the
light we are also at issue. I avoid any discussion on these
matters at present, as I am arranging a very extensive series
of experiments, which I hope to be enabled to complete pre-
viously to the next meeting of the British Association, before
which body I intend to bring my report.

I hope in the mean time that both Professor Draper and
Dr. Gardner will pursue their investigations. I have previously
stated it as my opinion that the conditions of the solar rays
are different in the tropical and temperate climes ; and I am
convinced that similar experiments, tried in different parts of
the world, will lead to many very important facts connected
with the solar emanations. I have only to beg that I may not
be made answerable for more than my printed papers will
warrant. My experiments have been seen by scores of per-
sons during the periods of my residence at Devonport and at
Falmouth, and the results have been as I have stated. That
light retards germination the common experience of every one
proves, but I am willing to allow that results obtained as mine
have been, with coloured media (although carefully analysed),
are liable to many objections. I have devised methods by
which I shall repeat these researches with the prismatic rays
during the coming spring and summer. Soliciting your in-
sertion of this short correction of Dr. Gardner,

I remain, dear Sir,

Yours very obediently,
Falmouth, Jan. 9, 1844. Robert Hunt.

Phil Mag. S. 3. Vol. 24. No. 157. Feb. 1844. H

[ 98 ]

XVIII. Abstract of a Memoir on the Chemical Constitution of
the Plants of Flax and Hemp, considered with relation to
the conditions of their Growth and Preparation. By Robert
Kane, M.D., fa,*

TN those plants which are cultivated for the purpose of being
ultimately employed as food, it is found that certain con-
stituents are withdrawn from the soil, partly of an organic
and partly of an inorganic character, which give to the plant,
or to certain portions of it, the constitution that adapts it for
sustaining the animal organism. Thus nitrogen, alkalies, and
lastly, phosphates, &c, are found as components of plants, and
the value of the crop yielded by a certain surface of ground
is proportional, generally speaking, to the materials which the
crop has taken up. If, therefore, wheat or oats, or potatoes
exhaust a soil, the agriculturist does not suffer thereby, for he
is paid for the materials of which they have exhausted it, and
when he replaces that loss of material by fresh manure he but
invests a certain capital, to be delivered at a profit in the next
season.

Many plants not employed as food, but ancillary to our
civilization as luxuries, or as utilized in the arts, are similarly
circumstanced. Thus when indigo or tobacco is grown, the
object is to obtain the greatest possible development of the co-
louring or of the narcotic principle. For this purpose, elements
are necessary of which the soil is thereby deprived, but the
impoverishing of the soil is paid for, by its materials being
sold as the valuable portion of the plant. In such cases,
therefore, to sustain the fertility of the soil, a continued sup-
ply, from external sources, of the materials which the plants
take up is required. The farmer must supply in the manure
the elements which he sends to market in the grown plants.

Dr. Kane then proceeded to point out that this principle
was limited as to certain classes of plants, by the fact, now
clearly established by the concurrent investigations of vege-
table physiologists and of chemists, that certain vegetable
substances, and those of high importance to mankind, were
not formed of materials abstracted from the soil, but were
produced by the vital action of the plant upon the constitu-
ents of the atmosphere. This class of bodies he characterized
as being constituted, generally, of carbon, united with hy-
drogen and oxygen in the proportions which form water. The
carbonic acid of the atmosphere, with the watery vapour con-
stantly existing in it, supplies the elements of sugar, gum,
starch, and ligneous fibre, and the oxygen of the carbonic

• Extracted from the Proceedings of the Royal Irish Academy, the
Memoir having been read December U, 1843.

Dr. Kane on the Chemical Constitution of Flax and Hemp. 99

acid, evolved by the vital action of the plants, tends, as it is
well known, to ameliorate the air we breathe. When, there-
fore, we take the sugar, or the woody fibre of a plant, we
have a material formed, as to its elements, independent of
the soil. For its formation is required a plant in healthy
vegetation, and for the plant to be in healthy vegetation, it
may require to abstract from the soil various materials, so that
the crop may actually be of a highly exhausting nature. Still
those materials do not go to the sugar or to the fibre ; they
exist in other portions of the plant; and if the sugar or fibre
be the valuable portion of the crop, as in reality usually occurs,
the elements which render its production costly are rejected,
and let to waste; they do not subserve any future useful pur-
pose, although nothing would be easier than to apply them
thereto.

Such is actually, according to Dr. Kane's idea, the condi-
tion of the growth of one plant of the highest importance to
agricultural industry in Ireland — that of flax, and also of an-
other, which although not now grown here, has been grown
with success, and, as he conceives, might still be cultivated
with considerable advantage, the hemp. In flax and hemp
the valuable portion of the plant is ligneous fibre; the purer
this fibre is, the more its value increases; yet the pure fibre
contains no element derived from the soil. It is well known
to be produced solely by the atmospherical constituents.
Hence, the intense exhausting nature of the flax and hemp
crops, which makes them dreaded by agriculturists, notwith-
standing the high money value of the crops, arises, accord-
ing to Dr. Kane, from causes of which the effects may be ob-
viated by attention to the true conditions of the growth and
composition of the plants, so that those fibre-crops, such as
flax and hemp, from being the most exhausting and expen-
sive, may be rendered the least injurious to the land, and per-
haps amongst the cheapest that can be grown.

As the chemical composition of these plants had never been
examined, Dr. Kane devoted himself to the determination, as
well of their organic as of their inorganic constituents, and
from an extensive series of analyses, of which the details are
given in the memoir, arrived at the following results : —
Composition of the stem of hemp, dried at 2] 2° F.

Carbon 39*94.

Hydrogen 5*06

Oxygen 48*72

Nitrogen 1'74

Ashes 4'54>

100*00
H2

100 Dr. Kane on the Chemical Constitution

Composition of the leaves of hemp, dried at 2J2°.

Carbon 40*50

Hydrogen 5*98

Nitrogen 1*82

Oxygen 29*70

Ashes 22-00

100-00
The ashes of the hemp plant were found to consist of

Potash 7*48

Soda -72

Lime 42-05

Magnesia 4*88

Alumina ..... -37

Silica 6*75

Phosphoric acid . . . 3-22
Sulphuric acid . . . 1*10

Chlorine 1-53

Carbonic acid .... 31*90

100-00
Dressed hemp fibre was found to give but 1-4 per cent, of
ashes, when dried at 212°. Its organic composition need not
be given, as it is identical with that of ordinary woody fibre,
which is well known. It therefore contains no nitrogen.

The characteristic constituents of the hemp plant are seen to
be nitrogen and lime. In these it is peculiarly rich, and with
these it is the duty of the agriculturist abundantly to supply it.
When hemp is steeped in order to separate the fibrous bark
from the internal stem, it is known that the water dissolves
certain substances out of the plants, and thereby acquires nar-
cotic properties. Dr. Kane evaporated a quantity of the hemp
liquor to dryness, and analysed the extract so obtained, in
order to trace what action the steeping had exerted on the
plant. He found the composition of the hemp extract, dried
at 212°, to be—

Carbon 28*28

Hydrogen 4*16

Nitrogen 3*28

Oxygen 15*08

Ashes 49*20

10000
If we exclude the ashes, the organic part consisted of

Carbon 55*66

Hydrogen 8*21

Nitrogen 6*45

Oxygen 29-68

100-00

of the Plants of Flax and Hemp, 101

This composition approaches to that of the azotized animal
substances, and surpasses the animal manures usually sold.
The water in which hemp has been steeped thus contains most
of the nitrogen of the plant, and if poured over the soil should
serve efficiently to restore its fertile powers.

The ashes of the hemp extract require also to be noticed,
for the plant, in steeping, gives up to the water especially its
soluble constituents. The ashes of the leaves of hemp contain
in 22 parts only 1*77 soluble in water, or 8*05 per cent., whilst
the ashes of the hemp extract contain in 49*2 parts, 29*70 parts
soluble in water, or 60*4 per cent. Thus almost all the alka-
line constituents of the ashes are dissolved out by the water,
whilst the earthy materials remain associated with the residual
portions of the stem.

Dr. Kane next examined the stem, as it remains after treat-
ment for the fibre, by steeping and peeling. Dried at 212°
this hemp residue consisted of

Carbon 56*80

Hydrogen 6*48

Nitrogen ..... "43

Oxygen 34*52

Ashes 1*77

100*00

The ashes contained but a trace of alkali, and it is seen that
the nitrogen has almost disappeared.

From these researches it is plain that, by the quantity of
nitrogen, of phosphoric acid, of potash, of magnesia, and of
lime, which the hemp takes from the soil, it must be, as ex-
perience proves it, a highly exhausting crop ; but as the ma-
terials so abstracted are not found in the valuable fibre, but
in the residual stem, the chaff, and the steeping liquor, all
these are available for the purpose of restoring to the soil what
had been taken up, and in fact, if it were possible to carry on
the processes of the preparation of the fibre without loss, the
same nitrogen and inorganic constituents might, as it would
appear from these chemical inquiries and from physiological
researches, serve for any number of successive crops of hemp ;
the fibre alone, generated at the expense of the atmosphere,
being sent out and sold, and thus the crop be absolutely de-
prived of all exhausting quality to the soil.

Dr. Kane's inquiries regarding the flax plant were of a pre-
cisely similar character to those described already in the case
of hemp, and have led him to similar conclusions affecting the
practical culture of this important plant. The general results
of his analyses are as follows: —

102 Dr. Kane on the Chemical Constitution

Stem of flax dried at 212°; the plant bad its usual amount
of leaves, but the seed vessels had not ripened.

Carbon 38*72

Hydrogen 7*33

Nitrogen '56

Oxygen 48*39

Ashes 5-00

100-00
There is a great difference here shown between the compo-
sition of the plants of hemp and flax, though they resemble
each other so much in their uses. The hemp contains a large
amount of nitrogen, the flax very little. The hemp contains
more oxygen than would form water with the hydrogen. Flax,
on the contrary, contains an excess of hydrogen. The differ-
ence is also remarkable in the composition of the ashes.
The ashes of the flax plant consist of

Potash 9-78

Soda 9-82

Lime 12*33

Magnesia 7*79

Alumina 6*08

Silica 21*35

Phosphoric acid . . . 10*84
Sulphuric acid . . . 2*65

Chlorine 2*41

Carbonic acid , . . . 16*95

100*00
The great quantity of lime which characterized the hemp
here disappears, and the peculiar quality of the ash is the
presence of soda and potash in equal quantities, much mag-
nesia, and especially the large proportion of phosphoric acid.
Dr. Kane has not met with any analysis of the ash of a plant
yielding the same amount of phosphoric acid, and hence the
exceedingly exhausting power of the flax crop is easily under-
stood.

Dr. Kane notices in this ash of flax, that the potash, soda,
sulphuric acid and chlorine are in a very simple relation to
each other, the numbers given above coinciding closely with
those of two atoms each of sulphuric acid and chlorine, six of
potash, and nine of soda. So that if (in the ash) all the soda
be taken as carbonate, the potash will be divided equally
among sulphuric, muriatic and carbonic acids. Dr. Kane
thinks that this simplicity is probably accidental, but suggests
it for attention in subsequent analyses of flax ashes from other
localities.

of the Plants of Flax and Hemp. 103

The steeping of flax to loosen the coat of fibrous bark is
accompanied by the solution of certain constituents of the
plant, as in the case of hemp. The extract of the steeping
water was analysed; it yielded, dried at 212°,

Carbon 30-69

Hydrogen 4*24

Nitrogen 2*24

Oxygen 20*82

Ashes 42-01

100*00
The organic part of this extract consisted therefore of

Carbon 52*93

Hydrogen 7*31

Nitrogen 3*86

Oxygen 35*90

100*00
Here, as in the case of hemp, the nitrogen of the plant is
concentrated, but the total quantity of nitrogen is not half so
great. In the ash of the extract, as in the case of hemp, the
soluble alkaline matters also preponderate. The ashes of the
plant yielded 33*90 per cent, of matters soluble in water;
whilst the ashes of the flax-steep extract yield 60 per cent, of
matters soluble in water. The flax-steep is therefore rich in
all the materials necessary to produce a new generation of
plants; and Dr. Kane stated, as a satisfactory confirmation of
the views put forward in his memoir, that in many instances
where agriculturists have sprinkled land with the water in
which flax has been steeped, they have found it a most active
manure.

After the flax fibre has been removed from the rotted stem,
the residue, or chaff, was found to be composed as follows: —

Carbon 50*34

Hydrogen 7*33

Nitrogen '24

Oxygen 40*52

Ashes 1*57

100*00
This is almost identical in composition with the residual hemp
stem, and may therefore be applied to the same uses. Restored
to the soil with the steep water, it should give back all that
the crop of flax had taken from the grounds, and thus the
valuable fibre being generated by the atmosphere, the great
source of expense in the cultivation of the plant might be re-
moved.

Dr. Kane finally placed before the Academy certain tables,

104- Mr. ConnelPs Chemical Examination of the

in which, taking the average quantity of produce from a statute
acre of fibre-crops and of food-crops, and comparing, from
the data supplied by the analyses of Sprengel, Boussingault,
and his own, the weights of materials of which the soil is ex-
hausted by each crop, it appeared that the fibre-crops were
actually more exhausting than the food-crops; whilst the agri-
culturist profits by the materials that the food-crops take out
of the ground, and the substances taken up by the fibre-crops
from the soil are at present actually rejected as waste and
valueless. Hence it is, as Dr. Kane considers, of much in-
terest to the agricultural industry of Ireland that the views of
ceconomizing the residues of the preparation of flax and hemp,
put forward in his memoir, be tested by practical men, as, if
they be found correct, and if those residues may be applied
with success to prepare and fit the soil for another crop, those
fibrous plants will be practically deprived of their exhausting
qualities, and the greatest disadvantage under which their ex-
tensive cultivation in this country labours, may be removed.

XIX. Chemical Examination of the Tagua Nut, or Vegetable
Ivory, By Arthur Connell, Esq*.

rT,HIS remarkable nut is now well known as being exten-
-*■ sively carved into a variety of ornaments, having a high
polish and exactly resembling the finest ivory.

The nuts which I have seen vary in size from a pigeon's to
a hen's egg. They are covered with a brown epidermis and
an outer thin shell. The inner substance of the nut is hard,
close-grained, and homogeneous in its structure to the naked
eye. Its specific gravity at 53° F. is 1*376.

Dr. Balfour, Professor of Botany in the University of Glas-
gow, has been so kind as to inform me that this vegetable
ivory "is the albumen (botanically speaking) of a palm called
Phytelephas Macrocarpa, which is found on the banks of the
river Magdalena, in the republic of Columbia. The natives
call it tagua, or cabeza de negre (negro's head)."

Mr. Cooper has stated that a thin slice of this substance,
examined under the microscope, exhibits a homogeneous
matter without any cellular or other elementary structure, but
traversed by parallel tubes evidently filled with an oily fluid f.

By a previous analysis of Dr. Douglas Maclagan J, this sub-
stance was found to contain

* Communicated by the Author j being an abstract of a paper read before
the Royal Society of Edinburgh.

•f Microscopic Journal, vol. ii. p. 97-

I Cormack's Journal of Medical Science, 1841, p. 614.

Tagua Nut, or Vegetable Ivory. 105

Hard woody fibre 76*5

Vegetable albumen 1'5

Bitter matter soluble in water and alcohol . 2#5

Gum with phosphate of lime 5'5

Ashes 0'5

Moisture 13-5

100-

The leading differences between this result and my own, I
believe, proceed from the azotized principles of vegetables
having been more fully studied by chemists since the above
analysis was made.

I employed in my examination the fine turnings of the ve-
getable ivory, which I obtained from one of the workmen in
London who was engaged in carving it. These turnings took
fire when heated and burned with flame, leaving a little white
ash. They did not yield oil when pressed between heated
metallic plates, but in the course of the analysis some fixed
oil was procured by solvents. No volatile oil was obtained
by distillation with water.

The mode of analysis followed was the following : — The
powder was first comminuted as much as possible by friction
in a mortar. It was then well rubbed with successive portions
of cold water, which were left in contact with it for a night;
and the milky fluids were allowed to deposit whatever was
mechanically suspended. Ultimately the mass was strained
through thick muslin and the liquid allowed to subside; the
several solutions were then boiled, and a little coagulated ve-
getable albumen separated.

A similar process of trituration was now repeated with suc-
cessive portions of boiling water, and subsidence allowed as
before.

To the emulsions prepared with cold and hot water, acetic
acid was added. A speedy coagulation ensued and a certain
quantity of an azotized substance was obtained, which, from
the manner in which it was procured, as well as from its lead-
ing characters with solvents, was either identical with or
nearly allied to legumin or vegetable casein.

By evaporating the liquid which had yielded the legumin
a quantity of gum was obtained.

No other matter was extracted from the residue by boiling
it for some time in a considerable quantity of water.

The dried mass was then treated with hot alcohol, and by
evaporation a small quantity of yellow fixed oil was procured.

Diluted caustic potash aided by a gentle heat took up no-
thing further; and diluted muriatic acid dissolved mere traces

106 Mr. Joule on the Intermittent Character of the Voltaic

of one or two matters, the quantities of which were too small

to admit of determining their precise nature.

The residual matter which had been treated with so many

solvents was regarded as lignin or woody matter. No starch

was found in any stage of the analysis.

The amount of water was ascertained by a heat of 240° and

the ashes by incineration.

The result of the analysis was as follows : —

Gum 6-73

Legumin or vegetable casein . 3*8
Vegetable albumen .... 0*42

Fixed oil 0*73

Ashes 0*61

Water 9*37

Lignin or woody matter . . . 8T34

Too7-

In the ashes were found phosphate of lime, sulphate of
potash, chloride of potassium, carbonate of lime, and a little
siliceous matter. A little iron present probably proceeded
from the tools of the turner.

XX. On the Intermittent Character of the Voltaic Current
in certain cases of Electrolysis ; and on the Intensities of
various Voltaic Arrangements. By J. P. Joule, Esq.*

1 T can hardly have escaped the notice of electricians that,
■*- in some instances of electro-chemical decomposition, the
needle of a galvanometer included in the circuit will indicate
by its unsteadiness a very irregular flow of electricity. I have
not, however, been able to meet with any description of the
phaenomena, which are generally so trifling in the extent of
their manifestation as to induce the belief that they arise from
accidental and unimportant causes. It is now more than a
year since I observed some very striking examples of the phae-
nomena in the course of some experiments on the calorific
effects of electrolysis, but I was too much interested in the
subject immediately in hand to allow them to occupy much
of my attention. They have since, however, appeared to me
to have an important bearing upon the theory of electrolysis,
and on this account to deserve the attention of philosophers.
I propose to begin by mentioning the old experiments just
referred to, and then to relate the progress I have recently
made in the investigation.

The following experiment was made on the 9th of July,

* Read before the Literary and Philosophical Society of Manchester,
December 26, 1843; and now communicated by the Author.

Current) and on the Intensities of Voltaic Arrangements. 107

1842. Two plates of iron were immersed in a dilute solution
of sulphuric acid and then connected with the poles of a bat-
tery consisting of six large cells of Daniell in series. After
electrolysis had proceeded for a few minutes, I observed that
the needle of a galvanometer which was included in the cir-
cuit indicated by its unsteadiness a very great irregularity in
the electrical current. On connecting only one cell of the
battery with the iron electrodes, the electrolysis appeared to
be carried on with freedom and the needle was pretty steady.

About the same time I made some experiments with elec-
trodes of copper immersed in a solution consisting of seven
parts of water and one part of strong oil of vitriol. In this
case the sudden jerking motion of the needle was not observed,
but it invariably happened that the current diminished very
rapidly during the first one or two minutes, and then began
to increase again, and continued to do so, until, after a certain
interval of time, it arrived nearly at the same degree of inten-
sity as was observed at first. I give the following as a fair
example selected out of a number of experiments which did
not differ much from one another.

A vessel containing dilute sulphuric acid was divided into
two compartments by a diaphragm of animal membrane. In
each of these a bright plate of copper exposing a surface of
about ten square inches was immersed. The copper plates
were then connected with a battery consisting of six large cells
of Daniell in series, a galvanometer furnished with a thick
copper wire bent into a circle of a foot diameter being included
in the circuit. Immediately after the circuit was closed the
current was sufficiently powerful to deflect the needle to 69°.
Then, noting the position of the needle at the end of each
quarter of a minute, I observed the following deflections, viz.
68°, 60°, 55°, 10°, 20°, 30°, 35°, 41°, 43°. Turning these
deflections into quantities of electricity, it appears that in the
short space of one minute the voltaic current declined to ^yth
of its first intensity, and that at the end of 1^' more it had
eight times the intensity that it had when at its lowest ebb.

1 met with very curious results by using amalgamated zinc
as the positive electrode of a battery of six large cells. The
needle was pretty steady at first, but after a short time it
began to oscillate in the most capricious manner through an
arc of about 10°. Sometimes it would remain steady for a few
seconds, then it would suddenly spring forwards, and before I
had time to make it steady in its new position of equilibrium
it would move backwards again.

It was natural enough to suppose that such extraordinary
irregularities of the current might be accompanied by a visible
change in the character of the electrode. And in this I was

108 Mr. Joule on the Intermittent Character of the Voltaic

not deceived, for on examining the amalgamated zinc I ob-
served the following very curious phenomenon : — At intervals
of one or two seconds a white shade overspread the surface of
the amalgamated zinc and then suddenly disappeared, leaving
the metal brilliant. The pulsations of the current were evi-
dently simultaneous with these sudden changes in the appear-
ance of the electrode, and the needle received a sudden im-
pulse every time the white film suddenly broke away.

All the above experiments were made more than a year ago,
those which follow are the experiments I have recently made
in the investigation of the same subject.

A plate of amalgamated zinc and a stout iron wire were
immeysed in a solution consisting of one part strong oil of
vitriol to six parts of water. The iron was connected with the
positive, the zinc with the negative electrode of a battery of
five large Daniell's cells, and a galvanometer was included in
the circuit. The instant that the circuit was completed a
powerful current was transmitted through it, hydrogen being
evolved from the negative zinc, whilst the positive iron was oxi-
dized and began to dissolve away. In a short time, however,
the intensity of the current began to decline very rapidly, and
the iron electrode, ceasing to be dissolved, assumed the pass-
ive state* described by Schcenbein, and began to evolve
oxygen gas, and continued to do so as long as I had patience
to watch it. On breaking the circuit and then closing it
afresh, the same phaenomena were repeated. Having now re-
duced the battery from five to three cells, the action of the iron
became intermittent. First it was dissolved, the needle being
at the same time deflected 45° ; then it began to evolve oxygen,
the needle at the same time declining rapidly until it stood at
15°; and then again the oxygen suddenly ceased to be evolved,
while at the same moment the needle sprang forwards and
began to oscillate about its former resting place at 45°. The
iron remained in each state about half a minute, and a white
film was observed to pass over its surface every time that the
oxygen was about to rise, and to disappear suddenly when the
evolution of oxygen ceased.

Having watched these curious phaenomena for some time,
it occurred to me to try the effect of connecting two cells with
the battery so as to divide the current between two positive
iron electrodes. On making the experiment I found that the
action of the iron was in both cells intermittent ; and, what
was very remarkable, that the condition of the iron electrodes

* Keir appears to have been the first to observe the passive state of iron.
Phil. Trans, for 1790. [Keir's priority of observation has already been
pointed out by Sir John Herschel and Mr. Faraday : see Phil. Mag. S. 3.
vol. ix. p. 122, vol. xi. p. 333.— Edit.]

Current, and on the Intensities of Voltaic Arrangements. 109

changed simultaneously. They always began to evolve oxygen
at about the same time; and when one of them ceased to
evolve oxygen and began to be oxidized and dissolved, the
same thing happened to the other at the same instant.

When both of the iron electrodes were evolving oxygen, it
was only necessary to lift one of them up a little, so as to ex-
pose a small portion of its surface to the air, and then to plunge
it into the acid again, in order to make both irons instantly
assume the opposite state. The same effect was also produced
by touching the immersed portion of one of the electrodes
with a piece of iron or zinc.

Now, as far as regards one electrolytic cell, the above phe-
nomena can be explained, I think, without much difficulty.
Adopting the theory of Professor Daniell, which, agreeably
to the theory of salts which has been promulgated by Davy
and Graham, supposes the positive metal to unite directly
with oxysulphion (S04), we can readily perceive that oxygen
must inevitably rise from the iron, whenever the oxysulphion
cannot be produced as quickly as is demanded by the inten-
sity of the battery. On the other hand, there will not, I think,
be much difficulty in admitting that the evolution of oxygen
may, by producing currents in the liquid, &c, have the effect
of restoring to the iron its original aptitude for dissolution ;
then, if the smallest portion of iron assume that state, it is evi-
dent that that portion will be positive with regard to the rest
of the iron evolving oxygen ; a current therefore will be esta-
blished through the acid from the former to the latter, and
the hydrogen thereby liberated immediately uniting with the
nascent oxygen of the passive portion of the iron, the whole
surface of iron will suddenly become clean and again combine
with oxysulphion. According to this view the advance of the
needle from its smallest to its greatest deflection ought to be
very sudden. This accords with my experience.

The simultaneous change of the state of two iron electrodes
in separate cells between which the current of the battery is
divided, may perhaps be explained by supposing that, when
one of the iron electrodes enters into the active state, the
sudden increase of the intensity of the current through its cell
diverts the current from the other cell to such an extent as to
allow its iron electrode also to assume the active state.

In general a current of a certain degree of intensity is re-
quisite in order to produce the intermittent effects. If it be
too low, the iron will continue to be dissolved ; if too high, the
iron will, after the first few moments of action, commence, and
then continue to evolve oxygen. A great deal seems also to
depend upon the quality of the iron employed. With some

110 Mr. Joule on the Intermittent Character of the Voltaic

specimens of iron and steel I could not succeed at all, whilst
with a piece of rectangular iron wire a quarter of an inch broad
and one-eighth of an inch thick, I was able to obtain intermit-
tent effects when using a battery consisting of two, three, four
and even five cells of Daniell. In this case the negative elec-
trode was a plate of platinized silver, the solution consisted of
six parts of water to one of strong oil of vitriol, and a dia-
phragm was employed in order to prevent the hydrogen rising
from the negative electrode from troubling the liquid in con-
tact with the positive iron. The results of the experiments
are given in the Table below, the second and third columns
of which give the deflections of the needle during the passive
and the active states of the iron, whilst the fourth contains the
difference between the currents observed in the two states.

Number of cells

Passive state.

Active state.

Difference.

in series.

2

2

43

884

3

23

50

926

4

34

53

837

5

43

56

737

In each of the four instances given in the table, the differ-
ent states succeeded each other at intervals of about half a
minute; and it was uniformly observed that the active state
was assumed with greater suddenness than the passive. It
will be seen also on inspecting the table, that, as might have
bsen anticipated from theory, the difference between the cur-
rents flowing in the different states is nearly a constant quan-
tity. '

On repeating my old experiments with a positive electrode
of amalgamated zinc, I find that whenever a battery of six or
ten large cells is connected with a plate of amalgamated zinc
immersed as a positive electrode in a dilute solution of sul-
phuric acid, the curious phaenomenon already adverted to
occurs. It commences at the bottom and edges of the amal-
gamated zinc, and generally goes on extending until the whole
surface is under its influence : the amalgamated zinc loses its
brightness in consequence of a white shade overspreading its
surface and giving it the appearance of frosted silver; this is
hardly formed before it suddenly disappears, and then a new
shade overspreads the surface only to vanish again as suddenly
as the one which preceded it. These alternations generally
succeed each other very rapidly, but I have sometimes seen
them occur at intervals of five seconds or more, and then I

Current, and on the Intensities of Voltaic Arrangements. Ill

have been able to prove, by the motions of the needle of the
galvanometer, that the disappearance of the film or white shade
is always accompanied by a sudden increase of the intensity
of the current.

On dividing the battery current between two similar elec-
trolytic cells, I observed that the disappearance of the white
film occurred at the same moment on both of the positive
electrodes of amalgamated zinc.

It is evident, therefore, that the phenomena obtained with
amalgamated zinc are, in a great measure, analogous to those
observed with iron ; but there is an important distinction be-
tween the two, inasmuch as no oxygen is evolved from amal-
gamated zinc when made positive in dilute sulphuric acid,
even when a very powerful battery is employed % So that we
see that amalgamated zinc continues to be dissolved even
when it has assumed a state analogous to that of passive iron
evolving oxygen. I think that this fact may be pretty well
explained by supposing that, in the active state, the zinc com-
bines immediately with oxysulphion, but that in consequence
of the too tardy arrival of that compound the zinc sometimes
combines with oxygen alone as a proper electrolytic action,
depending upon the secondary action of the sulphuric acid for
the removal of the film of oxide thus formed. It is easy to
see that in the latter case the intensity of the current will be
less than when the metal combines immediately with oxysul-
phion.

P.S. — Nearly the whole of the above had been written
before I was aware that Schcenbein had already observed the
intermitting passivity of iron. As, however, my experiments
with the iron electrode are considerably different from those
of Schcenbein, I have not thought it right to suppress them.
The experiments of Schcenbein were made in the following
mannerf: — The conducting wires of a powerful voltaic pair
were connected with two mercury cups; a plate of platinum
immersed in dilute sulphuric acid was connected with the
negative cup; then a piece of iron wire, previously connected
at one of its extremities with the positive mercury cup, was
made to complete the circuit by immersing the other extre-
mity in the dilute acid. Under these circumstances he did
not observe any disengagement of hydrogen from the negative
platinum, in consequence of the passivity of the iron electrode.
He observes that the apparatus may be made to lose this state

• Oxygen is evolved by zinc when the latter is made positive in a dilute
solution of potassa by three or four cells of Daniell in series.
f De la Hive's Archives de I' Electrwite, No. 5, p. 267-

112 Mr. Joule on the Intermittent Character of the Voltaic

of inactivity and so to produce the electrolysis of water by the
following means : —

1st. By putting the negative electrode in contact, for a
moment, with the positive electrode of iron. The instant they
are separated again a lively disengagement of hydrogen from
the negative electrode takes place, which, however, soon begins
to diminish, and ceases entirely at the end of some seconds.

2nd. By opening the circuit of the pile for some instants.
When it is closed again a lively disengagement of gas takes
place upon the negative electrode, which is soon succeeded by
the state of inactivity.

3rd. By putting the immersed portion of the positive elec-
trode of iron in contact with an oxidable metal, as, for example,
zinc, tin, copper, or even silver. But in this case the disen-
gagement of hydrogen from the negative electrode does not
last longer than some seconds.

4th. By establishing a communication between the two
mercury cups for a few moments, by means of a copper wire
three inches long and half a line thick. Then, the moment
the wire is removed again, a lively disengagement of hydrogen
takes place on the negative electrode, which does not however
last longer than a few seconds.

5th. By briskly agitating that portion of the positive iron
electrode which is immersed in the liquid, but without break-
ing the circuit.

Passing a variety of other interesting observations in Schcen-
bein's memoir, we come to that part of it which is most inti-
mately connected with our subject. At p. 278 of the Archives
he states, that when a communication is established between
the mercury cups by means of a wire of a certain length, there
succeed each other, at certain intervals, a lively disengage-
ment of gas on the negative electrode, and a time of cessation
of the electrolysis in the cell of decomposition. He observes
also, that after some time the alternations cease, and the posi-
tive iron electrode takes a permanent inactivity.

My own experiments on the intermittent states of a positive
electrode of iron differ from the prior experiments of the phy-
sicist of Bale with regard to the intensity of the pile employed.
His was a powerful single pair (Grove's?), mine was a series
of from two to five cells of Daniell. Hence, when the passive
state was assumed by the iron in Schcenbein's experiments,
the current was entirely cut off, because the battery used by
him had not sufficient intensity to produce the electrolysis of
water, except where the oxygen liberated could enter into
combination with the positive metal. But in consequence of
the intensity of the battery employed in my own experiments,

Current, and on the Intensities of Voltaic Arrangements. 113

the passive state of the iron was accompanied by the regular
decomposition of water into its gaseous elements.

It will be remarked also that Schoenbein did not observe
the intermitting effects until the intensity of the single cell
employed by him was still further diminished by the opening
of a new channel for the current by connecting the poles of
the cell by a wire of a certain length, whilst I have succeeded
in obtaining the alternations of state when using the whole
force of five very large cells of Daniell in series. We see
therefore that a powerful intensity of current is not always
able to retain the positive iron electrode in the passive state.

On the Intensities of various Voltaic Arrangements.

We know that the important law which has been established
by the labours of Ohm, Fechner and De la Rive, is expressed

by the formula E = p-, where A is the electro-motive force,

R the resistance to conduction of the whole circuit, and E is
the quantity of electricity circulating in a given time. There-
fore, if the resistances of different voltaic circles be made equal
to one another, the quantity of current will be proportional to
the electro-motive force; and hence we derive the following
simple method of determining the intensity of a battery. We
take an accurate galvanometer furnished with a coil of great
resistance, and connecting the arrangements under examina-
tion successively with it, we take the currents indicated by the
instrument as the measure of their intensities. I have in this
way obtained the following list of voltaic intensities, using a
galvanometer which, with the wires attached to it, presented
a resistance at least 300 times as great as that of most of the
cells under examination. I have made the ordinary cell of
Daniell the standard of comparison, calling its intensity 100.

No.

Negative elements.

Positive elements.

Inten-
sity.

1.

Platinum

Nitric acid

r Solution of \ /Amalgam of"!
\ potassa J \ potassium J

302

" 2.

Passive iron

do.

do. Amalgd zinc

220

3.

Coke

do.

do. do.

225

4.

Gold

do.

do. do.

234

5.

Platinum

do.

do. do.

234

6.

do.

do.

do. Iron

169

7.

do.

do.

do. Copper

120

8.

do.

do.

do. Silver

66

9.

do.

do.

do. Platinum

31

10.

do.

do.

f Solution of 1 Anmlgozinc
\ common salt J ■

198

11.

do.

do.

do. Iron

146

I

Viil. Map. S. «

,. Vol. 24. N

0.157. Feb. 18M. I

114 Mr. Joule on the Intensities of Voltaic Arrangements.
Table. (Continued.)

No.

Negative elements. Positive elements.

Inten-
sity.

■>a ui .• xt. • -l f Solution of 1
12. Platinum Nitric acid ■{ „^m,v „ u y

I (_ common salt J

Copper

116

13.

do.

do. do.

Silver

95

14.

do.

do. do.

Platinum

55

15.

do.

. / Solution ofsul- \
; \ pliate of soda J

Amalg'1 zinc

187

16.

do.

do. do.

Iron

147

17.

do.

do. do.

Copper

92

18.

do.

do.

do.

Silver

78

19.

do.

do.

do.

Platinum

17

20.

do.

do.

/Dilute sul- "1
1 phuric acid J

Amalgd zinc

187

21.

do.

do.

do.

Iron

140

22.

do.

do.

do.

Copper

91

23.

do.

do.

do.

Silver

53

24.

do.

do.
I" Peroxide of lead ]

do.

Platinum

37

25.

do.

-j and sulphuric > Solution of potassa

Amalgd zinc

277

L acid J

26

do.

do.
(" Peroxide of man- ")

do.

Iron

177

27.

do.

< ganese with sul- >
I phuric acid J
j" Peroxide of man- "1

do.

Amalgd zinc

237

28.

do.

< ganese and hy- >
L drochloric acid J

do.

do.

237

29.

do.

f Bichromate of 1
1 potassa J

do.

do.

161

30.

do.

do.
r Bichromate of T

f Dilute sul- \
\ phuric acid J

do.

102

31.

do.

< potassa and sul- >
[ phuric acid J

Solution of potassa

do.

207

32.

do.

do.

f Dilute sul- "1
\ phuric acid J

do.

161

33.

Copper

do.

do.

do.

116

34.

do.

f Bichromate of \
\ potassa J

do.

do.

79

35.

do.

Sulphate of copper Solution of potassa

do.

138

36.

do.

do.

do.

Iron

66

37.

do.

do.

do.

Copper

33

38.

do.

do.

/Solution of \
\ common salt J

Amalgd zinc

106

39.

do.

do.

do.

Iron

55

40.

do.

do.

do.

Copper

28

41.

do.

do.

f Solution ofsul-"!
\ [)hate of soda J

Amalg'1 zinc

104

42.

do.

do.

do.

Iron

59

43.

do.

do.

do.

Copper

8

44.

do.

do.

/Dilute sul- \
\ phuric acid /

Amalgdzine

100

Dr. A. W. Hofman on Bases in Coal-gas Naptha. 115
Table. (Continued.)

4.-..
4(>\

47.
48.

4').

5ft.

Negative elements.

Copper Sulphate of copper

do. do.

f Platinized \ J Dilute sul- \
X silver J \ phuricacidj
do- do.

do.
do.

do.

do.

Positive elements.

Inten
aity.

| Dilute sul- "I
\ phuric acid J
do.

do.

do.
J Solution of
X common salt

Iron
Copper
Amalg(1zinc
Iron

Amalg'1 zinc
Solution of potassa Amalgdzinc

}

49
4
65
17
68

The use of the peroxides of lead and manganese, as negative
elements of the voltaic pile, has been recently pointed out by
De la Rive*. By using the peroxide of lead with either dilute
sulphuric acid or a saline solution, he has produced a battery
of greater intensity than the pile of Grove f- It will be seen,
on reference to the table, that an arrangement consisting of
peroxide of lead moistened with sulphuric acid in contact with
platinum, and solution of potassa in contact with amalgamated
zinc, is half as intense again as the ordinary cell of Grove.

I may observe that a single cell of any of the arrangements
given in the table, the intensity of which is above 200, is able
to decompose water into its gaseous elements with facility.

I think we can deduce from the table a general law, which
may be stated thus: — "The difference between the intensities
of any two electro-positive metals immersed in similar solu-
tions is a constant quantity, whatever variations may be made
in the negative elements of the cells." Thus the difference
between the intensities of No. 47 and No. 48 is 48, while the
difference between the intensities of No. 20 and No. 21 is 47,
and between No. 44 and No. 45 is 51. Thus again the dif-
ference between No. 10 and No. 12 is 82, while that between
No. 38 and No. 40 is 78, or only one-twentieth less.

XXI. A Chemical Investigation of the Organic Bases contained
in Coal-Gas Naphtha. By Dr. Augustus William
Hofman, Assistant in the Giessen Laboratory %.

Preliminary Remarks.
f\F the numerous oleaginous fluids formed from the decom-
^-^ position of organic bodies by heat, those of wood and
of mineral coal have been, up to the present time, the most
carefully examined. The knowledge obtained from these

* Archives de t Electricite , No. 8, p. 166.

[t The use of peroxide of lead as the negative element was originally
proposed by Prof. Grove himself in Phil. Mag. S. 3. vol. xv.p. 290. — Edit.]
% Communicated by the Author.

I 2

116 Dr. A. W. Hofman on the Organic Bases

investigations is, however, by no means complete, indeed we
possess but a comparatively small number of elementary ana-
lyses of the many compound bodies which originate from de-
structive distillation. Without a knowledge of the constitu-
ents of those fluids, the numerous analogies which they pre-
sent to groups of other bodies must be inexplicable, and much
of the scientific interest attaching to them is lost.

There is, therefore, in this subject an extensive field open
for investigation.

About ten years since Runge* published a comprehensive
series of interesting researches upon coal-gas naphtha. He dis-
covered in it no less than six different bodies, which he desig-
nated by the following names, derived from their most pro-
minent features, &c. : cyanol, leucol, pyrrol ; carbolic, rosolic
and brunolic acids ; the three former act as bases, and the three
latter are of an acid or at least an electro-negative nature.

Of these substances, carbolic acid, cyanol and leucol are ex-
ceedingly interesting; the two first-mentioned particularly
were studied by Runge more extensively than the others, but
their elementary composition was not ascertained until lately,
when Laurentf analysed carbolic acid, which he denominated
hydrate of oxide ofphenyle, and from the study of the products
of its decomposition made it the basis of an interesting class
of compounds.

It appeared to me to involve sufficient interest to make the
other two basic bodies, cyanol and leucol, the subject of further
researches, and especially to ascertain their elementary com-
position.

Preparation of the Bases.

The coal-gas naphtha which I employed was obtained from
the asphaltum works of Dr. Ernest Sell, at Offenbach on the
Maine. The crude naphtha from the Belgium gas-works un-
dergoes distillation in large iron retorts. In this process there
passes over a large quantity of different oils, and in the alem-
bic remains a black, viscous fluid, which upon cooling solidifies
to an elastic mass of a brilliant colour. The oils which first
distil over are lighter than water, those following are heavier]
both mix with each other, and those which pass over last be-
come solid in a short time, from the deposition of naphthaline
in enormous quantities. In the course of the operation ammo-
nia is also disengaged, which is almost entirely dissolved.
The products are again submitted to distillation with the ad-
dition of a small quantity of sulphuric acid, in order to free

• Poggend. Annul. Bel. xxxi. pp. 65 and 513, and Bd. xxxii. pp. 308 and
328.

f Annul, dc Chim. et de Phj/s. ser. iii. torn. Hi., p. 195.

contained in Coal-gas 'Naphtha. 117

them entirely from ammonia. As soon as the lighter oils
(which are employed for dissolving caoutchouc) have passed
over, the receiver is changed in order to collect the heavier oils,
which still continue to deposit a large proportion of naphtha-
line. The bases of Runge, as I ascertained readily from pre-
liminary experiments, are most abundant in the heavier oils.
At first I followed Runge in his investigations, but his method
is exceedingly tedious, there is indeed no limit to rectifications.
I am inclined to believe the supposed necessity for their end-
less repetition has deterred others from repeating and extend-
ing his experiments; hence these bodies have not for a long
time engaged the attention of chemists, as they would other-
wise have done from their properties and chemical deportment.

The method I arrived at after some experiments on a small
scale was very simple. I transmitted a stream of hydrochlo-
ric acid gas through the oil until its absorption had ceased,
which at first was very active. I then agitated the solution
with water, which dissolved the combinations of the acid with
the basic oils, and also a small quantity of chloride of ammo-
nium. When the red aqueous liquid had separated from the
undissolved oil, it was drawn off with a siphon and evaporated
over a fire until pungent vapours escaped, which indicated
that the bodies in solution began to be decomposed. I filtered
the solution carefully in order to get rid of all the uncombined
oils, which were only mechanically mixed with the fluid, and
had separated in globules during the concentration, and de-
composed the clear solution with caustic potash. Globules
immediately appeared in the liquid, which after some time
floated upon the surface, of a dark brown colour, emitting an
insupportable smell.

This brown oil is a mixture of cyanol and leucol, containing
small quantities of ammonia, resinous matters (formed by the
action of the air upon the bases), and traces of a volatile sub-
stance with a rancid odour (perhaps Runge's pyrrol?), which
I have not hitherto perfectly isolated.

I have employed this method with a few variations for the
production of larger quantities. My friend, Ernest Sell, had
the kindness to offer me the use of his laboratory : without his
kind support it would have been almost impossible for me to
have proceeded with my researches.

Impregnating large quantities of oil with hydrochloric acid
gas would have been very tiresome. [ therefore agitated from
1000 to 1200 pounds of coal-gas naphtha in large carboys
with crude concentrated hydrochloric acid. After the lapse
of twelve hours the fluids had separated by virtue of their dif-
ferent specific gravities, and the undissolved oil floated on the

118 Dr. A. W. Hofman on the Organic Bases

surface of the acid solution. I drew off the acid liquor with
a siphon, and again agitated it with a fresh supply of oil. In
a short time I obtained a tolerably concentrated solution of
the basic compounds in hydrochloric acid. In order to sepa-
rate these bases I mingled the liquid, — previously filtered
through linen and gray bibulous paper, — with an excess of
milk of lime, in a large copper retort with a well-adapted con-
denser, and distilled over a strong fire. When properly
mixed the mass becomes very hot, and a large quantity of suf-
focating vapours are eliminated ; therefore the still-head must
be speedily affixed to prevent loss.

At the commencement of this process an opake liquid di-
stilled over, upon which floated drops of a blackish-brown oil
of a similar smell to that which was noticed at the filling of
the alembic. This liquid became clear when treated with hy-
drochloric acid, and yielded after concentration, when mixed
with caustic potash, oily globules, possessing the above-men-
tioned stifling odour.

In the course of the operation this peculiar smell diminished
greatly, and when about half of the liquid, which was in the
retort, had passed over, the odour changed completely and
was succeeded by one not disagreeable, in some respects re-
sembling oil of bitter almonds. At this stage of the process, the
aqueous solution, although turbid, contained only traces of
dissolved oil. I therefore changed the receiver, finding that
the oil now coming over differed from the former.

The basic fluids obtained in this manner still contained a
certain quantity of foreign oil, which must have mechanically
passed through the filters with the hydrochloric solution, and
distilled over with the bases. Of their presence I readily con-
vinced myself by dissolving the bases in hydrochloric or sul-
phuric acid. There remained small quantities of extraneous
oils, even when the bases were repeatedly separated and dis-
solved in acids. I succeeded in separating these foreign oils
by dissolving in aether and adding a dilute solution either of
sulphuric or hydrochloric acids. In this case the bases com-
bined with the acid, while the non-basic oils remained dis-
solved in the aather.

The acid solution ot the bases was carefully separated from
the aethereal solution of oil, and decomposed with hydrate of
potash. Carbonates of potash and soda, which will also
answer the purpose, must not be employed, because the car-
bonic acid generated is apt to carry off quantities of oily va-
pour. The decomposition succeeds best when performed in a
long narrow glass cylinder, the oil rises as a perfect homoge-
neous stratum to the surface of the menstruum, where it can be

contained in Coal-gas Naphtha. 119

removed by a pipette. Sometimes it appears in exceedingly
minute globules, which permeate the whole of the liquid and
obstinately refuse to cohere. When this occurs a small quan-
tity of chloride of sodium is to be added, and the liquor must
then be allowed to repose in a moderate temperature for a few
days. Should this experiment be unsuccessful, nothing re-
mains but to extract all water by immersing in the liquid hy-
drate of potash, or to distil anew the whole mass with water,
by which means the oil is collected in drops upon the distil-
late.

I obtained in this manner nearly four pounds of crude bases,
which still contained a considerable quantity of both oil and
water. The coal-gas naphtha was by no means perfectly ex-
hausted by this procedure, but since there was an enormous
quantity of this substance at my disposal, it was not necessary
for me to extract the whole of the contents. I obtained in in-
vestigations on a smaller scale, much more, in proportion ; still
the naphtha which I examined (making an approximate esti-
mation) contained scarcely more than one per cent, of basic oil.

Separation of Cyanol and Leucol.

For separating these two bases I deviated from Runge's
method. The observations which I had made in the distilla-
tion of the hydrochlorate combinations of the oil with lime,
led me very quickly to assure and easy separation.

As a characteristic property of cyanol, Runge has mention-
ed its behaviour towards a solution of chloride of lime, which,
when in contact with the smallest proportion of this salt, as-
sumes a rich violet-blue colour. This, of which I shall here-
after treat, is not produced by leucol. When I examined two
separate portions of my distillate, that which came over first
manifested itself to be very rich in cyanol, whereas there were
no traces of it in the latter, as was ascertained by its not being
coloured in the slightest degree by a solution of the above-
mentioned salt.

These experiments led me to expect that the two bases
could be separated from each other by distillation. I there-
fore submitted the oil containing cyanol to a new distillation,
changing the receiver as soon as the condensed liquid pro-
duced no blue reaction with chloride of lime. This was the
case when about four-fifths of the oil had distilled over. The
distillate possessed in a high degree the before-mentioned pe-
netrating smell, and was of a dark yellow colour, owing to a
small quantity of the brown matter, already adverted to, which
always accompanies the crude bases, and which, during the
process of distillation, continually trickles upon the sides of

120 Dr. A. W. Hofman on the Organic Bases

&'

the retort. When I left the yellow oil for some days in con-
tact with an equal weight of fused hydrate of potash in a closed
glass cylinder, there was formed at the bottom of the vessel
an aqueous solution of this alkali. The anhydrous oil was
then carefully removed with a dry pipette and quickly distilled
in a current of hydrogen gas, dried by means of sulphuric
acid. I received the distillate in three different portions. The
jirst might still have contained traces of water and ammonia,
the third was feebly coloured yellow, and its last portions pos-
sessed in a less degi'ee the property of colouring with chloride
of lime. The second portion was a beautiful, colourless iri-
descent liquid. In such cases, uniformity in the results of se-
veral analyses can alone satisfy us respecting the purity of a
substance, therefore I burned the first portion of my distillate
with oxide of copper, and then distilled the remaining part.
A small portion, which was received at the end of the distil-
lation, was also analysed with oxide of copper. The results
of the two analyses agreed perfectly ; to this I shall advert
hereafter. The middle or second portion of oil that passed
over in the second rectification I considered to be pure cyanol.
The portion that passed over last in the preparation of the
crude bases, and which, as was remarked, did not produce a
blue reaction with chloride of lime, was dehydrated and distilled
twice in a stream of dry hydrogen gas. The middle portion
of the product of distillation was a liquid smelling not very
unpleasantly, possessing a slight yellow hue, and of an extra-
ordinary refractive power. I burned it with oxide of copper;
the results obtained agreed with the results of further analyses,
which were made with different portions of this oil many times
redistilled. This slightly coloured liquid may therefore be
regarded as pure leucol.

The above-described method depends upon the unequal vo-
latility of the two bases; from the same cause very varying
quantities of each oil are obtained when different portions of
the heavy coal-gas naphtha are employed. Dr. Fabian von
Feilitzsch procured, by the treatment of an oil which was ob-
tained from the same source as mine, pure leucol, unmixed with
the slightest trace of cyanol. A considerable quantity of an-
thracene (paranaphthaline) was deposited from this oil, which
proves that it must have belonged to the last period of distil-
lation. I repeated and investigated this experiment with a
large quantity of coal-gas naphtha which Dr. Sell had distilled.
This oil, which on cooling partly consolidated into naphtha-
line, contained only leucol. In the same way I have examined
the oil which passes over after the evolution of the hydrocar-
bons. This was not free from leucol, but it contained an in-

contained in Coal-gas Najrtitha. 121

comparably greater quantity of cyanol. Generally leucol pre-
dominated in the oils which I investigated ; its quantity may
amount to double that of the cyanol obtained. My method
of separation will yield the bases in a state of purity, but it has
this fault, that a considerable quantity of oil, which distils over
between the first and last portions, cannot be resolved into
cyanol and leucol. A more minute examination of the salts
showed that a further separation might be effected by a sim-
pler process. I shall again refer to this subject.

I may here observe that my analyses were made in the la-
boratory of Professor Liebig, to whom I am indebted for many
valuable suggestions in pursuing this investigation.

1. Cyanol.

Composition. — I shall first treat of cyanol, because the in-
vestigation of its composition and relations guided my subse-
quent inquiries. The preparation of this base for analysis has
been already described.

I. 0*4631 grm. of cyanol gave 1*302 of carbonic acid and
0-3185 of water.

II. 0-2807 grm. of cyanol gave 0*789 of carbonic acid and
0*197 of water.

Assuming that there was no oxygen present, as there is none
in nicotine, coniine, chinoline or sinnamine, an assumption
which it will be seen in the sequel was warranted, I neglected
in these analyses to determine the nitrogen.

The per-centage of the elements was as follows : —

I. II.

Carbon . . . 77*316 77*298

Hydrogen . . 7*6*2 7*798

Nitrogen . . . 15*042 14*904

100*000 100*000

These numbers correspond with the formula C12 H7 N, the
calculated values of which agree very closely with the mean
of my analyses.

Composition per cent.
Theory. Mean.

12 atoms of Carbon* . 910*248 77*491 77*307
7 ... Hydrogen 87*36 7*437 7*720

1 ... Nitrogen. 1 77*04 15*072 14*973

1174*648 100*000 100*000
In order to control the given formula, the double salt of
hydrochlorate of cyanol and chloride of platinum was pre-
pared and its amount of platinum determined. The salt which
served for the analyses was in beautiful crystals, and had been
* Equivalent of carbon = 75*854.

122 Dr. A. W. Hofman on the Organic Bases

formed from separate portions of cyanol. I dried it at 212°
Fahr., at which temperature it lost some of its hygroscopic
moisture.

I. 0*5573 grm. chloride of platinum and cyanol gave 0*1833
grm. platinum = 32890 per cent.

II. 0*8083 grm. chloride of platinum and cyanol gave 0*2658
grm. platinum = 32883 per cent.

From the above is obtained the following atomic weight of
cyanol : —
• I. II.

1176*45 1177*248

agreeing closely with 1174*648, which is the calculated one.

Some time since Fritzsche*, in investigating the effect of
alkalies upon indigo-blue, discovered an acid, the anthranilic,
which, when distilled, is decomposed into carbonic acid and a
base, which he described under the name of Aniline. Erd-
mannf showed this body to be identical with crystalline^ which
was several years ago detected by UnverdorbenJ in the. dry
distillation of indigo. Zinin § obtained a short time ago in a
most remarkable manner by the action of sulphuret of ammo-
nium upon the combinations of peroxide of nitrogen with some
hydrocarbons, organic bases, one of which, benzidam, was re-
cognized by Fritzsche || as identical with aniline.

The results obtained by these chemists from the analysis
of aniline and benzidam, are similar to those found by myself
in examining cyanol, and both exhibit the same formula,
C12H7N.

The following arithmetical mean of our results, and the for-
mula reduced to per centages, will show their identity.

Aniline. Benzidam. Cyanol. Formula Cj.-, H?N.

Carbon . 77*782 77*826 77*307 77'49l"

Hydrogen 7*54 7*615 7*720 7'437

Nitrogen . 14-83 14-84 J_l'97^ 15*072

100-152 100-281 100-000 100-000

Fritzsche ascertained the atomic weight of aniline by analy-
sing the oxalate and hydrochlorate of this body, whereas Zinin
on the other hand employed for this purpose the double salt
of platinum.

Chlor. of plat. & benz. Chlor. of plat. & cyanol.
Mean amount of Platinum per cent 32*501 32*886

Deduced atomic weight . . . 1221-33 1176-849

. , 1

Theoret. atomic weight 1174*648

The striking similarity of these numbers renders the iden-

* Bullet. Sclent, de St. Petcrsb. t. vii. No. 12. and t. viii.

f Erdmann's Jottrn. b. xx. p. 457- J Poggend. AnnaL b. viii. p. 397.

§ Bullet. Scient. de St. Petcrsb. t. x. No. 18. || Ibid.

contained in Coal-gas Naphtha. 123

tity of cyanol with the bodies described under the names of
crystalline, aniline and benzidam, highly probable. The de-
scription of the properties of cyanol, as they have been ob-
served by Runge and myself, their comparison with the che-
mical relations of crystalline, aniline and benzidam, together
with the uniformity in the analyses, will, I am sure, establish
this point.

Properties of cyanol. — Cyanol, when obtained simply by
distillation, is not absolutely pure; it still contains traces of a
volatile body, which gives it a most disagreeable and penetra-
ting smell, yet the quantity of this contamination is so minute
that it has no influence on the analysis ; I therefore only know
of its presence from the smell. If the base be combined with
oxalic acid and then separated from the oxalate, after being
purified by several recrystallizations in absolute alcohol, the
smell entirely disappears. The following statements refer to
cyanol obtained in this manner unless otherwise mentioned.

The base obtained from the oxalate is a clear and limpid
liquid, possessing an oily consistency, a slight agreeable vinous
odour, an aromatic and burning taste. It is not solidified at
a temperature of — 4° Fahr., nor does it lose anything of its
limpidity. It is in a high degree volatile, evaporating at
nearly all temperatures. The stain which it imparts to paper
vanishes in a few moments. Its boiling point is 359*6 Fahr.;
according to Fritzsche aniline boils at 44-2*6 Fahr. I have
several times most carefully repeated the experiment, having
kept the cyanol boiling for a quarter of an hour at each repe-
tition without obtaining a different result. When touched
with a lighted body the oil inflames and burns brightly, de-
positing large quantities of carbon. Colourless cyanol when
exposed to the air quickly assumes a yellow tinge, and after
some time is converted into a dark resinous substance. This
alteration is more rapid at high temperatures; it is therefore
convenient to distil this base in a stream of hydrogen or car-
bonic acid gas, but it may also be obtained clear without this
precaution if distilled very rapidly over an open fire.

Cyanol is heavier than water; its sp. gr. is 1*020 at 68° Fahr.
Fritzsche gives 1*028 as the sp. gr. of aniline; that of benzi-
dam has not been determined by Zinin. It is a remarkable
fact that cyanol, purified only by distillation, is rather lighter
than water.

This base is copiously dissolved in every proportion by
aether, alcohol, pyroxylic spirit, acetone, aldehyde, sulphuret
of carbon, fatty and essential oils. Water takes it up in very
small quantities, and on the other hand cyanol imbibes water.
iEther withdraws the oil from the aqueous solution, whereas

124 Dr. A. W. Hoftnan on the Organic Bases

caustic or carbonated alkalies, chloride of sodium and sulphate
of magnesia separate it.

In its behaviour with water the cyanol obtained from the
oxalate differs essentially from that purified only by distillation.
The latter is dissolved in very large quantities by water, and
on the other hand absorbs as large a proportion. In conse-
quence of a suggestion of Berzelius 1 intended to determine the
quantity of water absorbed by cyanol at an ordinary temperature,
to ascertain whether there was a hydrate C12 H7 N + HO formed.

For this investigation I employed distilled cyanol, the purest
at that time being unknown to me. I mixed the oil with an
excess of water and kept it at the temperature of 53^° Fahr.;
after some days had elapsed the menstruum had separated into
two distinct layers; the undermost was a solution of the base
in water, and the upper stratum hydrated cyanol. I removed
carefully the latter with a pipette and ignited it with oxide of
copper.

0*3918 grm. hydrated cyanol gave 0'7528 of carbonic acid
and 0*3154 of water.

The analysis represented centesimally : —
Carbon .... 52-838
Hydrogen . . . 8*944

In 100 parts, therefore, of hydrated cyanol are contained 30
parts of water, which shows that 100 parts of the dry base at
53 2° Fahr. combine with 45 parts, or nearly half their weight.

The formula C12 H7 N -f HO corresponds to the following
per-centage : —

Carbon .... 70*719
Hydrogen . . . 7*756
100 parts of the hydrate contain 8-7 parts of water.

Although from the preceding experiments cyanol appears
to have absorbed nearly three times as much water as was
sufficient to constitute a simple hydrate, still this is by no
means a satisfactory proof of the non-existence of such a com-
bination, because the perfectly pure cyanol, as was previously
stated, dissolves a considerably smaller quantity of water.

The following differences between the pure and smelling
cyanol are worthy of remark. The former dissolves in water
the more the higher the temperature, and a boiling saturated
solution becomes milk-white upon cooling with separation of
the oil. Cyanol, on the contrary, which still contains the
smelling substance, presents a similar anomaly to that which
Geiger has ascribed to coniine. A cold saturated solution of
this oil in water, or of water in the oil, becomes cloudy even
by the warmth of the hand ; and this appearance increases
as the temperature is raised. If the liquid is boiled the

contained in Coal-gas Naphtha. 125

whole separates, two distinct layers become visible, the one
principally composed of oil and the other of water. When
a solution of the smelling base is heated with a few drops of
sulphuric or oxalic acids, the oil separates in globules and the
fluid only clarifies on the addition of an excess of acid. This
reaction does not take place with pure cyanol.

Neither this base nor an aqueous solution of it affects tur-
meric or reddened litmus paper, but the watery solution co-
lours distinctly green the violet syrup of dahlias. A glass
rod moistened with hydrochloric acid and held over cyanol
is enveloped in white vapours; this also takes place with nitric
acid, but in a less degree.

Cyanol, like the essential oils, dissolves sulphur, and when
heated, in very large quantities ; upon cooling, the sulphur is
deposited in shining prisms. Phosphorus is also dissolved,
but in smaller quantities, but not arsenic. Further, it dissolves
camphor and colophony, but copal may be melted under the
oil without any portion of it being imbibed. Cyanol, even
boiling, dissolves only traces of caoutchouc. This base, like
carbolic acid, coagulates albumen.

Cyanol powerfully disperses and refracts light; from the
measurement of the smallest divergence I ascertained its index
of refraction to be 1 '577.

It is a very bad conductor of electricity, if it possesses this
property at all. An electrical current, obtained from four
pairs of a very powerful Bunsen battery, did not produce the
least decomposition, although the platinum points became red-
hot when in contact under the liquid. A very delicate galva-
nometer, which was brought at the same time under the influ-
ence of the electrical current, was not removed above 3° from
its normal position, even when I endeavoured to produce a
maximum of deviation by breaking and closing the circuit.
Distilled water under the same circumstances effected a de-
viation of 80°.

With respect to the physiological properties of this body,
Runge mentions that he killed leeches by immersing them in
a watery solution of cyanol. I have tried its effect upon the
organism of larger animals; for instance, I injected into the
throat of a rabbit about 0*5 grm. of oil mixed with three times
as much water; in a few minutes violent spasms ensued ac-
companied by difficult and slow breathing, and a complete
prostration of all power. The pupil was dilated, and on
shaking the floor the rabbit was seized with violent spasmodic
contractions, similar to those produced on narcotized frogs.
Twenty-four hours afterwards it had not recovered its normal
condition ; the breathing was still slow, and the mucous mem-

126 Dr. A. W. Hofman on the Organic Bases

brane of the mouth highly inflamed. The blood of the killed
animal presented nothing remarkable. These effects are,
perhaps, to be attributed rather to the caustic nature of the
oil than to any particular action upon the organization, such
as that produced by nicotine and coniine. The above-men-
tioned dilatation of the pupil after injection induced me to rub
the eye of a healthy animal with a few drops of the oil ; no
dilatation took place, as is the case with daturine and hyo-
scyamine, but on the contrary, a surprising contraction re-
sulted, in consequence of irritation.

I have already adverted to the reactions produced by cyanol
when in contact with other bodies, as for example the colori-
zation with hypochlorite of lime, and in general with the hy-
pochlorites of the alkalies. The smallest drop spreads in violet
clouds through the whole liquid. This colour is very ephe-
meral, for after some minutes the solution becomes coated with
an iridescent film, and the blue appearance changes to a dirty
red. The salts of this base are also transiently coloured blue.
Acids change the blue colour immediately to a red. An al-
coholic solution of cyanol when treated with a hypochlorite
assumes a less intense colour ; a solution in aether, on the
other hand, is not affected. If the cyanol contains leucol, it
will be easily recognized by brownish oil-globules floating upon
the surface of the homogeneous blue liquid. It is evident that
the presence of much ammonia will prevent this blue reaction.

I was desirous of ascertaining whether crystalline, aniline
and benzidam would exhibit the same characteristic reaction.
For this purpose I subjected indigo-blue to dry distillation in
order to obtain crystalline. , During the process there passed
over with sublimed indigo and carbonate of ammonia a black
empyreumatic oil possessing an insufferable smell, which only
partially dissolved in hydrochloric acid. The filtered solu-
tion, distilled with caustic potash, afforded at the commence-
ment ammonia, and towards the end an oil mixed with water,
which immediately communicated the violet colour to a solu-
tion of chloride of lime ; yet in this experiment the proportion
of crystalline obtained was exceedingly small.

Through the kindness of Mr. William Sullivan I obtained
a quantity of pure anthranilic acid, the aniline prepared from
which gave the same reaction as cyanol, with chloride of lime.

Lastly, I prepared Zinin's benzidam. A solution of nitro-
benzide in spirit of wine was treated with ammonia and then
with hydrosulphuric acid until sulphur no longer crystallized
from the liquid. The filtered solution was submitted to di-
stillation, towards the end of which benzidam flowed over in
considerable quantities, which produced the above-mentioned

contained in Coal-gas Naphtha. 127

blue reaction. Nicotine, coniine, chinoline, sinnamine pro-
duce noeffecton the hypochlorites; naphthalidam gives a feeble
violet tint, which cannot be mistaken for the cyanol reaction.

As a further test for cyanol, Runge has noticed the property
its salts possess, of imparting an intense yellow colour to fir-
wood and the pulp of the elder-tree. The base itself does not
possess this power. This reaction is also shown by the acid
solutions of crystalline, aniline and benzidam. In general,
however, very little weight is to be attached to such coloriza-
tions ; the salts of leucol, which, according to Runge, do not
possess this property, produce it notwithstanding after some
time; the salts of coniine, sinnamine and chinoline also, tinge
fir-wood slightly yellow, and the salts of naphthalidam pos-
sess this property perhaps in a still higher degree than even
the salts of cyanol. As a characteristic of aniline Fritzsche
alludes to its behaviour with an aqueous solution of chromic
acid. This affords, both in aniline, and solutions of its salts,
a precipitate, which, after the concentration of the supernatant
liquor, assumes a green, blue, or black colour. Crystalline,
benzidam and cyanol, give the same reaction.

Naphthalidam and its salts effect the same change with
chromic acid, but the other before-mentioned bases do not.

The peroxide and protoxide salts of iron are decomposed
by cyanol with the separation of hydrated peroxide or prot-
oxide of iron. In the same manner alumina and oxide of
zinc are separated from the sulphates of these bases.

Cyanol produces in a solution of sulphate of copper a pale
green crystalline deposit, which is not altered by a temperature
of 212°, and is very probably a double compound of sulphate
of copper and cyanol. This precipitate is also occasioned in
chloride of copper, which, if in excess, becomes quickly black.

Similar double compounds are produced in solutions of
chlorides of mercury, platinum, palladium and gold. The
double salt of mercury is white, that of platinum or palladium
a fine orange-yellow. The precipitate which occurs in the
gold solution is reddish-brown, of the colour of ferrocyanide
of copper. When chloride of gold is mixed with hydro-
chlorate of cyanol, there is obtained a yellow deposit, which
speedily becomes of a dirty reddish-brown colour.

Cyanol throws down from solutions of chloride of tin and
chloride of antimony a copious curdy precipitate. Neutral
and basic acetate of lead are only rendered turbid.

Cyanol produces no precipitate with nitrate of silver or the
oxides of mercury, and the salts of nickel, cobalt, manganese
and chromium, chlorides of barium and calcium, sulphate of
magnesia, cyanide, ferrocyanide and sulphocyanide of potas-
sium.

128 Dr. Stenhouse on the

On the other hand, an infusion of gall-nuts throws down
cyanol in brownish-yellow flakes, which are soluble in hot
water and alcohol.

[To be continued.]

XXII. On the Products of the Distillation of Meconic Acid.
By John Stenhouse, P/t.Z).*

WHEN either meconic or komenic acids are subjected to
distillation at a temperature varying from 510° to 550°
F., they yield pyromeconic acid, which passes into the receiver
partly as an oily liquid and partly as a crystalline sublimate.
Towards the close of the distillation a few crystals of another
acid, to which we shall subsequently advert, appear on the sides
and neck of the retort.

Pyromeconic acid, as first obtained, is very impure, being
contaminated with empyreumatic oil, and some acetic acid; it
may be easily freed from the greater portion of these impuri-
ties by pressing it between folds of blotting-paper, and cau-
tiously re-distilling it at a comparatively low temperature; the
pyromeconic acid is then nearly colourless, and if again pressed
and repeatedly crystallized out of spirits of wine, in which it
is very soluble, may be easily obtained in large colourless
prisms. The acid should be crystallized from rather concen-
trated solutions and quickly dried, as the crystals become co-
loured if exposed to the air in a moist state for any length of
time. A portion of pyromeconic acid thus purified was dried
at 212° F. and analysed in the usual way.

I. 0*381 gramme of substance gave 0*7435 of carbonic acid
and 0-123 of water.

II. 0*404 gramme gave 0*783 of carbonic acid and 0*128
of water.

III. 0*323 gramme gave 0629 of carbonic acid and 0*1105
of water.

At. Calculated numbers. Percent.
10 Carbon = 764350= 54*046
4 Hydrogen = 49918= 3*530
6 Oxygen = 600*000 = 42424
100*00 10000 10000 1414268 100000

These analyses give the formula C10H3O6 + HO for the
hydrated acid, which agrees precisely with Robiquet's deter-
mination.

Pyromeconic acid, when pure, hardly, if at all, reddens lit-
mus paper, and if a single drop of any of the alkalies is added
to its solution, it is immediately rendered alkaline.

* Communicated by the Chemical Society; having been read November
7, 1843.

I.

II.

III.

Carbon

53-95

53*58

53*84

Hydrogen

3-58

3-52

3*80

Oxygen

42*47

42*90

4236

Products of the Distillation of Meconic Acid. 129

In this, as well as in some other respects, it very closely
resembles pyrogallic acid, except that pyromeconic acid is not
so easily oxidable as pyrogallic acid.

A considerable quantity of an alcoholic solution of potash
was added to a portion of pyromeconic acid, also dissolved in
hot spirits of wine. The liquid became slightly yellow, and
on cooling deposited crystals of the acid containing only a
very little potash. The crystals were pressed between folds
of blotting-paper and re-dissolved, and on crystallizing them
a second time they contained merely a trace of potash, and
that obviously owing to the extreme solubility of both the
acid and the potash, which rendered their complete separation
a matter of some difficulty. A great excess of ammonia was
next added to an alcoholic solution of pyromeconic acid, which
also soon rendered it slightly yellow. It was dried under the.
air-pump. The pyromeconic acid crystallized out, with its
properties apparently unaltered. It gave no indication of
containing ammonia when boiled with either hydrate of lime
or potash. When subjected to analysis —

0*3498 gramme of substance gave 0*6745 of carbonic acid
and 0*11 of water.

Pyromeconic acid. — Calculated numbers.

Carbon . . 53-31 54*046

Hydrogen . 3*49 3*530

Oxygen . . 43*20 42-424

100*00 100*000

It is obvious, from a comparison of the result of this ana-
lysis with the calculated numbers of pyromeconic acid, that
the ammonia had not combined with the acid, which, if al-
tered at all, had only been slightly oxidated.

The only salt of pyromeconic acid of which any account
has hitherto been published, is the lead salt. It was formed
by Robiquet by adding hydrated oxide of lead to a hot solu-
tion of pyromeconic acid. When the acid was nearly satu-
rated, the lead compound precipitated ; Robiquet found the
salt to be anhydrous, and to consist of C10 H3 05 -f PbO.

Pyromeconate of Copper.

When an excess of hydrated oxide of copper is boiled for
a short time with pyromeconic acid, the solution becomes of
a bright green colour, and when filtered an emerald-green
coloured salt is deposited on cooling. It crystallizes in long
slender delicate needles, which are very brittle. The crystals
require a good deal of hot water to dissolve them, and are very
slightly soluble in cold water, or alcohol in either hot or cold.
When dried under the air-pump, and then kept for some time

Phil. Mag. S. 3. Vol. 24. No. 157. Feb. 1844. K

II. 0-3392

• ••

III. 1-0113

• ..

I.

II.

Carbon 42-15

4-2-28

Hydrogen 2-15
Oxygen 28*30
CuO 27-40

2-27
28-05
27-40

130 Dr. Stenhonse on the

at 212° F., they lost no weight. They were subjected to ana-
lysis in the usual way.

I. 0-5203 gramme of this salt gave 0-7933 of carbonic acid
and 0-1011 grm. of water.

II. 0*3684 gramme gave 0*5633 of carbonic acid and 0*0755
of water.

Per cent.
I. 0-7292grm.of thesaltgave 0*2002 oxideofcopper = 27*45.

0-0917 =2743.

0-0277 =27*34.

Calculated numbers. Percent.
Carbon 10= 764*350= 42*522
Hydrogen 3= 37*438= 2*099
Oxygen 5= 500*000= 27*822
CuO = 495*70 = 27-577

100*00 100*00 1797-488 = 100*000

This gives the formula C10 H3 05 4- CuO for the constitu-
tion of the salt, and the number 1301- 78 for the atomic weight
of the acid, the calculated number being 1302.

Pyromeconate of Iron.

When pyromeconic acid is boiled with hyd rated peroxide
of iron, it combines with the oxide, and forms a brownish-red
powder, which, when neutral, is very little soluble either in
hot or cold water. When a few drops of an acid are added;
however, it dissolves with a fine deep red colour, and is de-
posited on cooling in small cinnabar-red crystals. The best
way of obtaining this salt in crystals of considerable size and
beauty, is by adding persulphate of iron to a tolerably dilute
boiling solution of pyromeconic acid, and allowing it to cool
very slowly.

The crystals after some hours are deposited in very distinct
rhomboids, having a blood-red colour, and a lustre very much
resembling garnets. Though not large their crystalline form
is easily discernible by the naked eye. The crystals are hard
and brittle, and their powder is of a cinnabar-red colour.
They are very difficultly soluble either in hot or cold water ;
and their solutions are of a reddish yellow colour.

When dried at 2I2°F. they were subjected to an analysis
in the usual way.

I. Determination of the iron: 0'5527 grm. of the salt gave
0-112 of oxide of iron =19*80 percent.

II. 0*9135 grm. of the salt gave 0*184 of oxide of iron
= 20*14 per cent.

III. 0*426 grm. of the salt gave 0*086 grm. of oxide of iron
= 20*19 per cent.

Products of the Distillation qfMeconic Acid. 131

I. 0*421 grm. of the salt, dried at 212° F. and burned with
chromate of lead, gave 0*71 7 of carbonic acid and 0*092of water.

Calculated numbers.

Per cent.

Found.

Carbon

30 = 2293-05

46-95

46-80

Hydrogen

9= 112-315

2-30

2-43

Oxygen

15= ] 500-000

30-71

30-71

Fe2Q8

= 978-426

20-04

20-06

4883-791 100-00 100*00

It is evident from these analyses that the iron salt is neu-
tral, the atoms of acid being as three to two. It gives pre-
cisely the same formula, C]0H3O5, for anhydrous pyrome-
conic acid as the lead and copper salts; the atomic weight
found being 1299-7; the calculated, 1302.

When oxide of silver is added to a cold solution of pyro-
meconate of silver, it immediately combines with the acid and
forms a bulky light-grayish compound, which is but slightly
soluble, and has very little permanence. It quickly decom-
poses even in the cold, becoming of a deep black colour. If
it is boiled in a glass tube the inner surface of the tube be-
comes coated with a mirror of metallic silver, as the oxide is
reduced without the evolution of any gas. This reaction
with oxide of silver, together with the red colour which the
acid strikes with a persalt of iron, form a very easy means of
detecting pyromeconic acid.

When pyromeconic acid is added to a solution of nitrate
of silver no precipitate or change of colour appears, and it re-
quires to be boiled for some time before even a very partial
reduction of the oxide is effected. But if a few drops of am-
monia are first added to the nitrate of silver, the pyromeconic
acid immediately produces a bright yellow gelatinous preci-
pitate. This precipitate is pretty soluble both in cold water
and in alcohol, it also quickly changes its colour even in
vacuo, becoming dark brown, owing, I apprehend, to partial
decomposition. When strongly heated it deflagrates slightly ;
one portion gave 51*80 per cent, of oxide of silver, which ap-
proaches the calculated quantity in neutral pyromeconate of
silver, which is 52-70 per cent, of oxide. The examination of
this salt is attended with considerable difficulty, owing to its
little permanence. Pyromeconic acid occasions no precipi-
tate in solutions of salts of lime, barytes, or strontian. If hy-
drate of lime however is heated in a solution of pyromeconic
acid it dissolves, and when the liquor begins to cool the lime-
salt is deposited in small hard crystals, the form of which I was
unable to determine.

As Liebig has observed, pyromeconic and pyromucic acids
are isomeric bodies; their composition in 100 parts and their

K2

132 Dr. Stenhouse on the

atomic weights being the same. They are not identical sub-
stances, however, and may be easily distinguished, among
others, by the following particulars : — Pyromeconic acid gives
a fine red with persalts of iron, while pyromucic acid gives
only a dirty green colour ; pyromeconic acid does not preci-
pitate basic acetate of lead, while pyromucic acid does so ;
pyromucic acid reduces oxide of silver, with evolution of gas,
as a black powder, while pyromeconic acid precipitates it as a
metallic mirror ; lastly, pyromucic acid, when boiled with
alcohol and sulphuric acid, forms an aether, this pyromeconic
acid fails to do. I may mention also, that I was unable to ob-
tain an aether with either meconic or komenic acids.

Pyromeconic acid may be procured in considerable quan-
tity by distilling the acid meconate of copper. This salt falls
as a greenish-yellow precipitate when pyromeconic acid is
added to acetate of copper. Pyromeconic acid may also be
obtained, but in very small quantity, by the distillation of the
neutral meconate of copper. This salt has a fine emerald-
green colour, and is formed when a soluble salt of copper is
treated with meconate of potash. When meconate of lime is
distilled it only yields empyreumatic products, without any
trace of pyromeconic acid.

It has already been mentioned that meconic and komenic
acids, when distilled, yield small quantities of another acid be-
side the pyromeconic. Towards the end of the distillation,
when the greater portion of the pyromeconic acid has passed
over, a few feathery crystals of this second acid condense on
the sides and neck of the retort. This acid was first noticed
by Gruner and Robiquet. Berzelius has called it the pyro-
komenic acid. This name would be very appropriate if this
acid were produced by the distillation of komenic acid alone,
but it appears not quite so suitable when we consider that the
fixed products of meconic and komenic acids are precisely the
same. Dr. Gregory considers this acid to be the komenic
acid perhaps regenerated. The best way of procuring it is
by sublimation, but even this yields it in very small quantity.

A portion of meconic acid was introduced into Dr. Mohr's
apparatus, and sublimed at as high a temperature as the paper
would bear without charring. The greater portion of the
pyromeconic acid, which was also formed at the same time,
was either destroyed or dissipated, but a little of it, together
with the crystals of the second acid, which 1 shall call the pa-
rakomenic, were found in the cap and on the diaphragm. The
crystals of parakomenic acid may be easily separated from the
pyromeconic acid, with which they are mixed, by washing
them either with cold water or alcohol, in both of which pa-

Products of the Distillation of Meconic Acid. 133

rakomenic acid is but slightly soluble, while pyrorneconic acid
very readily dissolves.

The parakomenic acid when first sublimed is usually of a
deep yellow colour, but this is removed by dissolving it in
boiling water, and digesting it with animal charcoal. When the
filtered solution cools, the parakomenic acid is deposited in
hard crystalline grains, with merely a faint tinge of yellow ;
their powder is quite white. The crystals of parakomenic
acid, if not quickly dried, become of a pale red colour, and
their solutions, though reddish while cold, become nearly co-
lourless when heated. In appearance, degree of solubility in
water and alcohol, and in their strongly acid taste and reac-
tion, they closely resemble komenic acid, from which they
differ however in some particulars, as I shall presently notice.
When dried at 212° F. and analysed with chromateof lead, —

I. 0*3319 gramme of substance gave 0*5603 grm. of carbonic
acid and 0-0805 of water.

II. 0*2788 gramme of substance gave 0*470 of carbonic acid
and 0*071 of water.

III. 0-3873 gramme of substance gave 0*653 of carbonic
acid and 0*09 1 2 of water.

Calculated

1.

11.

in.

At.

numbers.

Carbon

46*67

46*61

46*62

12

Carbon 46*62

Hydrogen

2*69

2*82

2-61

4

Hydrogen 2*53

Oxygen

50*64

50*57

50-77

10

Oxygen 50*85

100*00 10000 100-00 100*00

It is evident from the results of these analyses, that the com-
position per cent, and formula, both of komenic and parako-
menic acids, are the same. Though this is the case, and
though they closely resemble each other in most of their pro-
perties, the two acids may be easily distinguished by the fol-
lowing reactions : — I. Parakomenic acid produces no preci-
pitate in a solution of acetate of copper, while komenic acid
causes a copious yellowish-green precipitate. II. When
added to neutral acetate of lead, parakomenic acid throws
down a small quantity of a white granular precipitate, which
instantly disappears if the liquor is stirred, being apparently
dissolved by the free acetic acid present, for it reappears and
remains permanently on the addition of a few drops of am-
monia. Komenic acid, on the contrary, causes in acetate of
lead a bulky, slightly yellowish precipitate, which does not
dissolve even when treated with a great excess of acetic acid.
Neither komenic nor parakomenic acids precipitate salts of
lime, barytes, or strontian. They produce no change in solu-
tions of corrosive sublimate or chloride of platinum. They
agree in giving a pale red to a solution of tartar-emetic, but

134? Dr. Stenhouse on the.

cause no precipitate. Parakomenic acid also closely resem-
bles komenic acid in its silver salts, of which it appears to
form two. When a solution of the acid is added to nitrate of
silver it occasions a copious white granular precipitate, and
when the acid has been previously neutralized with ammonia
it gives with nitrate of silver a yellow gelatinous precipitate.
I attempted to determine the atomic weight of parakomenic
acid from a small quantity of these salts, but the results were
unsatisfactory, and unfortunately I have not yet been able to
procure enough of the acid to enable me to repeat them.

I may mention however that both salts gave less of silver
in the 100 parts than the corresponding salts of komenic
acid. Both acids also give a similar deep red colour with
persalls of iron, and on standing for a few hours they both
yield a quantity of small, hard, jet-black crystals, of which, in
the instance of komenic acid, a description and analysis is
herewith subjoined. The crystals formed by parakomenic
acid cannot be distinguished by their appearance and general
properties from those of komenate of iron, though the compo-
sition is probably different.

Komenate. of Peroxide of Iron.

When persulphate of iron is added to a cold and pretty con-
centrated solution of komenic acid, the liquid becomes of a deep
blood-red colour. After standing for some hours it grows
paler, and a considerable quantity of very small jet-black
crystals are slowly deposited on the sides and bottom of the
vessel. These crystals have a considerable resemblance to
coarsely-pounded charcoal, but they possess a much higher
lustre. In chemical authors komenic acid is said to form a
very soluble salt with peroxide of iron. This is a mistake,
however, and can only have arisen from the circumstance that
this black powder is so unlike a salt, that it has hitherto been
overlooked. The crystals are very hard, are gritty between the
teeth, and have scarcely any taste. They are difficultly so-
luble in either cold or hot water. When rapidly washed with
cold water it runs off' nearly colourless, but if the water is kept
for some time standing over them, it becomes of a pink colour.
Their solution in boiling water has a pale red colour. Their
powder is dark reddish-brown. They were dried at 212° F.
and subjected to analysis. Percent.

I. 0-4230 gramme gave 00784 peroxide of iron = 18-53
II. 0-4690 0-086 =1831

III. 0-4325 0-081 =18-72

IV. 0-3434 0-064.5 =18*76

I. 0-3534 gramme, when ignited with chromate of lead, gave

0*450 carbonic acid and 00953 water.

I.

fit.

At.

Carbon 35-20

34-97

24

Hydrogen 2-99

2-84

11

Oxygen 43*23

43*61

23

Fe2Oa 18-58

18-58

100-00

100-00

Products of the Distillation ofMeconic Acid. 135

II. 0-3510 gramme gave 0-444 of carbonic acid and 0-0920
of water.

Calculated numbers. Percent.
Carbon =1834-440= 34-94
Hydrogen = 137*274= 2-61
Oxygen =2300'000= 43*80
Fe2 O3 = 978-424= 18-63
5250-138 100- 00

These analyses give the formula KO + 2 HO+KO+HO
+ Fe2 03 + 4 aq = C12 H4 O10+2 HO C]2 H4 O]0+ HO + Fe2
Oa + 4aq.

The salt employed for these determinations was made at
three different times.

Komenate of ammonia, when treated with persulphate of
iron, also yields this salt, just as when the acid alone is em-
ployed. I determined the quantity of iron contained in a
portion of salt made in this way and dried at 212° F. 0*2782
gramme gave 0*052 of peroxide = 18*69 per cent.

If persulphate of iron is added to a hot instead of a cold
solution of kornenic acid, which is kept for some hours at a
temperature of about 150° F., none of these jet-black crystals
are deposited. The red colour also of the liquid disappears,
and it becomes transparent, and has a deep yellow colour.

A solution of galls produces in it no change of colour, but
it gives a deep blue with red prussiate of potash, and a white
precipitate changing to blue with the yellow prussiate. These
reactions clearly show that the peroxide of iron has been re-
duced by the kornenic acid to the state of protoxide. The red
colour of the liquid was not restored by the addition of more
kornenic acid, but it immediately returned when more per-
sulphate of iron, or a little nitric acid was added. A consi-
derable quantity of persulphate was poured into the liquid,
which was then set aside in a hot stove for twelve hours, when
its red colour had again disappeared, and a small quantity of
bright yellow crystals were found at the bottom of the liquid.
These crystals were but of small size, but larger than those of
the komenate of iron; they possessed considerable lustre,
and were but slightly soluble in cold water. When heated
they inflamed and left a considerable quantity of black oxide
of iron, which showed that they consisted of an organic pro-
tosalt of iron.

If the crystals are digested with solution of potash the iron is
precipitated in the state of protoxide ; and when the clear alka-
line liquor is separated and is neutralized with muriatic acid,
it does not strike a red colour with persulphate of iron, which
clearly shows that the acid in these crystals is not the kornenic.

C 136 )

XXI II. A speculation touching Electric Conduction and the
Nature of Matter. By Michael Fakaday, Esq., D.C.L.,
F.R.S.

To Richard Taylor, Esq.

Dear Sill, Royal Institution, January 25, 1844.

[ AST Friday I opened the weekly evening-meetings here
-*-^ by a subject of which the above was the title, and had no
intention of publishing the matter further, but as it involves
the consideration and application of a few of those main ele-
ments of natural knowledge, facts, I thought an account of
its nature and intention might not be unacceptable to you,
and would at the same time serve as the record of my opinion
and views, as far as they are at present formed.

The view of the atomic constitution of matter which I think
is most prevalent, is that which considers the atom as a some-
thing material having a certain volume, upon which those
powers were impressed at the creation, which have given it,
from that time to the present, the capability of constituting,
when many atoms are congregated together into groups, the
different substances whose effects and properties we observe.
These, though grouped and held together by their powers, do
not touch each other, but have intervening space, otherwise
pressure or cold could not make a body contract into a smaller
bulk, nor heat or tension make it larger ; in liquids these atoms
or particles are free to move about one another, and in vapours
or gases they are also present, but removed very much further
apart, though still related to each other by their powers.

The atomic doctrine is greatly used one way or another in
this, our day, for the interpretation of pha3nomena, especially
those of crystallography and chemistry, and is not so carefully
distinguished from the facts, but that it often appears to him
who stands in the position of student, as a statement of the
facts themselves, though it is at best but an assumption ; of
the truth of which we can assert nothing, whatever we may
say or think of its probability. The word atom, which can
never be used without involving much that is purely hypo-
thetical, is often intended to be used to express a simple fact,
but, good as the intention is, I have not yet found a mind that
did habitually separate it from its accompanying temptations;
and there can be no doubt that the words definite proportions,
equivalents, primes, &c, which did and do express fully all
the facts of what is usually called the atomic theory in che-
mistry, were dismissed because they were not expressive
enough, and did not say all that was in the mind of him who

Mr. Faraday on the Nature of Matter. 137

used the word atom in their stead ; they did not express the
hypothesis as well as the fact.

But it is always safe and philosophic to distinguish, as much
as is in our power, fact from theory; the experience of past ages
is sufficient to show us the wisdom of such a course ; and con-
sidering the constant tendency of the mind to rest on an as-
sumption, and, when it answers every present purpose, to forget
that it is an assumption, we ought to remember that it, in such
cases, becomes a prejudice, and inevitably interferes, more or
less, with a clear-sighted judgement. I cannot doubt but that
he who, as a mere philosopher, has most power of penetrating
the secrets of nature, and guessing by hypothesis at her mode
of working, will also be most careful, for his own safe progress
and that of others, to distinguish that knowledge which con-
sists of assumption, by which I mean theory and hypothesis,
from that which is the knowledge of facts and laws ; never
raising the former to the dignity or authority of the latter, nor
confusing the latter more than is inevitable with the former.

Light and electricity are two great and searching investiga-
tors of the molecular structure of bodies, and it was whilst
considering the probable nature of conduction and insulation
in bodies not decomposable by the electricity to which they
were subject, and the relation of electricity to space contem-
plated as void of that which by the atomists is called matter,
that considerations something like those which follow were
presented to my mind.

If the view of the constitution of matter already referred to
be assumed to be correct, and I may be allowed to speak of the
particles of matter and of the space between them (in water, or
in the vapour of water for instance) as two different things, then
space must be taken as the only continuous part, for the par-
ticles are considered as separated by space from each other.
Space will permeate all masses of matter in every direction
like a net, except that in place of meshes it will form cells,
isolating each atom from its neighbours, and itself only being
continuous.

Then take the case of a piece of shell-lac, a non-conductor,
and it would appear at once from such a view of its atomic
constitution that space is an insulator, for if it were a con-
ductor the shell-lac could not insulate, whatever might be the
relation as to conducting power of its material atoms; the
space would be like a fine metallic web penetrating it in every
direction, just as we may imagine of a heap of siliceous sand
having all its pores filled with water; or as we may consider
of a stick of black wax, which, though it contains an infinity
of particles of conducting charcoal diffused through every

1 38 Mr. Faraday on Electric Conduction

part of it, cannot conduqt, because a non-conducting body
(a resin) intervenes and separates them one from another, like
the supposed space in the lac.

Next take the case of a metal, platinum or potassium, con-
stituted, according to the atomic theory, in the same manner.
The metal is a conductor ; but how can this be, except space be
a conductor? for it is the only continuous part of the metal,
and the atoms not only do not touch (by the theory), but as we
shall see presently, must be assumed to be a considerable way
apart. Space therefore must be a conductor, or else the
metals could not conduct, but would be in the situation of the
black sealing-wax referred to a little while ago.

But if space be a conductor, how then can shell-lac, sulphur,
&c. insulate? for space permeates them in every direction.
Or if space be an insulator, how can a metal or other similar
body conduct?

It would seem, therefore, that in accepting the ordinary
atomic theory, space may be proved to be a non-conductor in
non-conducting bodies, and a conductor in conducting bodies,
but the reasoning ends in this, a subversion of that theory alto-
gether ; for if space be an insulator it cannot exist in conduct-
ing bodies, and if it be a conductor it cannot exist in insula-
ting bodies. Any ground of reasoning which tends to such
conclusions as these must in itself be false.

In connexion with such conclusions we may consider
shortly what are the probabilities that present themselves to
the mind, if the extension of the atomic theory which chemists
have imagined, be applied in conjunction with the conducting
powers of metals. If the specific gravity of the metals be di-
vided by the atomic numbers, it gives us the number of atoms,
upon the hypothesis, in equal bulks of the metals. In the fol-
lowing table the first column of figures expresses nearly the
number of atoms in, and the second column of figures the
conducting power of, equal volumes of the metals named.
Atoms. Conducting power.

1-00 gold 6-00

1-00 silver 4-66

1-12 lead 0-52

1-30 tin 1-00

2-20 platinum ... 1*04

2-27 zinc 1*80

2-87 copper 6'33

2-90 iron 100

So here iron, which contains the greatest number of atoms
in a given bulk, is the worst conductor excepting one. Gold,
which contains the fewest, is nearly the best conductor; not

and the Nature of Matter. 1 39

that these conditions are in inverse proportions, for copper,
which contains nearly as many atoms as iron, conducts better
still than gold, and with above six times the power of iron.
Lead, which contains more atoms than gold, has only about
one-twelfth of its conducting power; lead, which is much
heavier than tin and much lighter than platina, has only
half the conducting power of either of these metals. And
all this happens amongst substances which we are bound to
consider, at present, as elementary or simple. Whichever way
we consider the particles of matter and the space between
them, and examine the assumed constitution of matter by this
table, the results are full of perplexity.

Now let us take the case of potassium, a compact metallic
substance with excellent conducting powers, its oxide or hy-
drate a non-conductor; it will supply us with some facts ha-
ving very important bearings on the assumed atomic con-
struction of matter.

When potassium is oxidized an atom of it combines with
an atom of oxygen to form an atom of potassa, and an atom
of potassa combines with an atom of water, consisting of two
atoms of oxygen and hydrogen, to form an atom of hydrate
of potassa, so that an atom of hydrate of potassa contains
four elementary atoms. The specific gravity of potassium is
0*865, and its atomic weight 40 ; the specific gravity of cast
hydrate of potassa, in such state of purity as I could obtain it,
I found to be nearly 2, its atomic weight 57. From these,
which may be taken as facts, the following strange conclusions
flow. A piece of potassium contains less potassium than an
equal piece of the potash formed by it and oxygen. We may
cast into potassium oxygen atom for atom, and then again
both oxygen and hydrogen in a twofold number of atoms, and
yet, with all these additions, the matter shall become less and
less, until it is not two-thirds of its original volume. If
a given bulk of potassium contains 45 atoms, the same bulk
of hydrate of potassa contains 70 atoms nearly of the metal
potassium, and besides that, 210 atoms more of oxygen and
hydrogen. In dealing with assumptions I must assume a little
more for the sake of making any kind of statement ; let
me therefore assume that in the hydrate of potassa the atoms
are all of one size and nearly touching each other, and that
in a cubic inch of that substance there are 2800 elementary
atoms of potassium, oxygen and hydrogen; take away 2100
atoms of oxygen and hydrogen, and the 700 atoms of potas-
sium remaining will swell into more than a cubic inch and a
half, and if we diminish the number until only those contain-
able in a cubic inch remain, we shall have 430, or thereabout.

140 Mr. Faraday on "Electric Conduction

So a space which can contain 2800 atoms, and amongst them
700 of potassium itself, is found to be entirely filled by 430
atoms of potassium as they exist in the ordinary state of that
metal. Surely then, under the suppositions of the atomic
theory, the atoms of potassium must be very far apart in the
metal, /. c. there must be much more of space than of matter
in that body : yet it is an excellent conductor, and so space
must be a conductor; but then what becomes of shell-lac, sul-
phur, and all the insulators? for space must also by the theory
exist in them.

Again, the volume which will contain 430 atoms of potas-
sium, and nothing else, whilst in the state of metal, will, when
that potassium is converted into nitre, contain very nearly the
same number of atoms of potassium, i. e. 416, and also then
seven times as many, or 2912 atoms of nitrogen and oxygen
besides. In carbonate of potassa the space which will con-
tain only the 430 atoms of potassium as metal, being entirely
filled by it, will, after the conversion, contain 256 atoms more
of potassium, making 686 atoms of that metal, and, in addi-
tion, 2744 atoms of oxygen and carbon.

These and similar considerations might be extended through
compounds of sodium and other bodies with results equally
striking, and indeed still more so, when the relations of one
substance, as oxygen or sulphur, with different bodies are
brought into comparison.

I am not ignorant that the mind is most powerfully drawn
by the phenomena of crystallization, chemistry and physics
generally, to the acknowledgement of centres of force. I feel
myself constrained, for the present hypothetically, to admit
them, and cannot do without them, but I feel great difficulty
in the conception of atoms of matter which in solids, fluids
and vapours are supposed to be more or less apart from each
other, with intervening space not occupied by atoms, and per-
ceive great contradictions in the conclusions which flow from
such a view.

If we must assume at all, as indeed in a branch of know-
ledge like the present we can hardly help it, then the safest
course appears to be to assume as little as possible, and in that
respect the atoms of Boscovich appear to me to have a great
advantage over the more usual notion. His atoms, if I un-
derstand aright, are mere centres of forces or powers, not par-
ticles of matter, in which the powers themselves reside. If,
in the ordinary view of atoms, we call the particle of matter
away from the powers a, and the system of powers or forces
in and around it in, then in Boscovich's theory a disappears, or
is a mere mathematical point, whilst in the usual notion it is

and the Nature of Matter. 141

a little unchangeable, impenetrable piece of matter, and m is
an atmosphere of force grouped around it.

In many of the hypothetical uses made of atoms, as in cry-
stallography, chemistry, magnetism, &c, this difference in the
assumption makes little or no alteration in the results, but in
other cases, as of electric conduction, the nature of light, the
manner in which bodies combine to produce compounds, the
effects of forces, as heat or electricity, upon matter, the dif-
ference will be very great.

Thus, referring back to potassium, in which as a metal the
atoms must, as we have seen, be, according to the usual view,
very far apart from each other, how can we for a moment
imagine that its conducting property belongs to it, any other-
wise than as a consequence of the properties of the space, or
as I have called it above, the ml so also its other properties
in regard to light or magnetism, or solidity, or hardness, or
specific gravity, must belong to it, in consequence of the pro-
perties or forces of the m, not those of the a, which, without
the forces, is conceived of as having no powers. But then surely
the m is the matter of the potassium, for where is there the least
ground (except in a gratuitous assumption) for imagining a
difference in kind between the nature of that space midway
between the centres of two contiguous atoms and any other
spot between these centres? a difference in degree, or even in
the nature of the power consistent with the law of continuity,
I can admit, but the difference between a supposed little hard
particle and the powers around it I cannot imagine.

To my mind, therefore, the a or nucleus vanishes, and the
substance consists of the powers or m; and indeed what no-
tion can we form of the nucleus independent of its powers?
all our perception and knowledge of the atom, and even our
fancy, is limited to ideas of its powers: what thought remains
on which to hang the imagination of an a independent of the
acknowledged forces? A mind just entering on the subject
may consider it difficult to think of the powers of matter in-
dependent of a separate something to be called the matter, but
it is certainly far more difficult, and indeed impossible, to think
of or imagine that matter independent of the powers. Now
the powers we know and recognize in every phaenomena of the
creation, the abstract matter in none ; why then assume the
existence of that of which we are ignorant, which we cannot
conceive, and for which there is no philosophical necessity ?

Before concluding these speculations I will refer to a few
of the important differences between the assumption of atoms
consisting merely of centres of force, like those of Boscovich,
and that other assumption of molecules of something specially
material, having powers attached in and around them.

142 Mr. Faraday on Electric Conduction

With the latter atoms a mass of matter consists of atoms
and intervening space, with the former atoms matter is every-
where present, and there is no intervening space unoccupied
by it. In gases the atoms touch each other just as truly as in
solids. In this respect the atoms of water touch each other
whether that substance be in the form of ice, water or steam ;
no mere intervening space is present. Doubtless the centres of
force vary in their distance one from another, but that which
is truly the matter of one atom touches the matter of its neigh-
bours.

Hence matter will be continuous throughout, and in con-
sidering a mass of it we have not to suppose a distinction be-
tween its atoms and any intervening space. The powers around
the centres give these centres the properties of atoms of
matter; and these powers again, when many centres by their
conjoint forces are grouped into a mass, give to every part of
that mass the properties of matter. In such a view all the
contradiction resulting from the consideration of electric in-
sulation and conduction disappears.

The atoms may be conceived of as highly elastic, instead of
being supposed excessively hard and unalterable in form; the
mere compi'ession of a bladder of air between the hands can
alter their size a little; and the experiments of Cagniard de
la Tour carry on this change in size until the difference in
bulk at one time and another may be made several hundred
times. Such is also the case when a solid or a fluid body is
converted into vapour.

With regard also to the shape of the atoms, and, according
to the ordinary assumption, its definite and unalterable cha-
racter, another view must now be taken of it. An atom by
itself might be conceived of as spherical or spheroidal, or
where many were touching in all directions, the form might
be thought of, as a dodecahedron, for any one would be sur-
rounded by and bear against twelve others, on different sides.
But if an atom be conceived to be a centre of power, that
which is ordinarily referred to under the term shape would
now be referred to the disposition and relative intensity of the
forces. The power arranged in and around a centre might
be uniform in arrangement and intensity in every direction
outwards from that centre, and then a section of equal inten-
sity of force through the radii would be a sphere; or the law
of decrease of force from the centre outwards might vary in
different directions, and then the section of equal intensity
might be an oblate or oblong spheroid, or have other forms;
or the forces might be disposed so as to make the atom polar;
or they might circulate around it equatorial ly or otherwise,
after the manner of imagined magnetic atoms. In fact nothing

and the Nature of Matter. 143

can be supposed of the disposition of forces in or about a solid
nucleus of matter, which cannot be equally conceived with
respect to a centre.

In the view of matter now sustained as the lesser assump-
tion, matter and the atoms of matter would be mutually pene-
trable. As regards the mutual penetrability of matter, one
would think that the facts respecting potassium and its com-
pounds, already described, would be enough to prove that
point to a mind which accepts a fact for a fact, and is not
obstructed in its judgement by preconceived notions. With
respect to the mutual penetrability of the atoms, it seems to
me to present in many points of view a more beautiful, yet
equally probable and philosophic idea of the constitution of
bodies than the other hypotheses, especially in the case of che-
mical combination. If we suppose an atom of oxygen and an
atom of potassium about to combine and produce potash, the
hypothesis of solid unchangeable impenetrable atoms places
these two particles side by side in a position easily, because
mechanically, imagined, and not unfrequently represented;
but if these two atoms be centres of power they will mutually
penetrate to the very centres, thus forming one atom or mole-
cule vvith powers, either uniformly around it or arranged as
the resultant of the powers of the two constituent atoms; and
the manner in which two or many centres of force may in this
way combine, and afterwards, under the dominion of stronger
forces, separate again, may in some degree be illustrated by
the beautiful case of the conjunction of two sea waves of dif-
ferent velocities into one, their perfect union for a time, and
final separation into the constituent waves, considered, I think,
at the meeting of the British Association at Liverpool. It
does not of course follow, from this view, that the centres shall
always coincide; that will depend upon the relative disposi-
tion of the powers of each atom.

The view now stated of the constitution of matter would
seem to involve necessarily the conclusion that matter fills all
space, or, at least, all space to which gravitation extends (in-
cluding the sun and its system); for gravitation is a property
of matter dependent on a certain force, and it is this force
which constitutes the matter. In that view matter is not
merely mutually penetrable, but each atom extends, so to say,
throughout the whole of the solar system, yet always retaining
its own centre of force. This, at first sight, seems to fall in
very harmoniously with Mossotti's mathematical investiga-
tions and reference of the phaenomena of electricity, cohesion,
gravitation, &c. to one force in matter ; and also again with
the old adage, " matter cannot act where it is not." But it

1 44- Geological Society.

is no part of my intention to enter into such considerations as
these, or what the bearings of this hypothesis would be on the
theory of light and the supposed aether. My desire has been
rather to bring certain facts from electrical conduction and
chemical combination to bear strongly upon our views regard-
ing the nature of atoms and matter, and so to assist in distin-
guishing in natural philosophy our real knowledge, i. e. the
knowledge of facts and laws, from that, which, though it has
the form of knowledge, may, from its including so much that
is mere assumption, be the very reverse.

1 am , my dear Sir,

Yours, &c,
Michael Faraday.

XXIV. Proceedings of Learned Societies.

GEOLOGICAL SOCIETY.

[Continued from p. 76.]

April 26, 1843 " /^vN changes in the Temperature of the Earth, as
(continued). V_/ a mode of accounting for the subsidence of the
Ocean, and for the consequent formation of Sea-beaches above its
present level." By Robert Harkness, Esq., Ormskirk.

The formations which are referrible to a period that succeeded the
most recent tertiary epoch, and preceded the period when the earth
was inhabited by man, and which the author terms the post-tertiary
formations, may be divided into the so-called diluvium, the erratic
blocks which have been transported by the action of glaciers, and
the remains of ancient sea-beaches.

The so-called diluvium usually consists of clay and erratic boul-
ders, of which the latter are often identical in substance with the
rock of some more or less distant mountain-chain ; and in such cases
may be considered to have been derived from the chains in question.
Since deep valleys, of anterior date to the diluvium, often intervene
between the rocks in situ and the districts over which the derivative
boulders are spread, the transport of these masses has in later times
been attributed by geologists to the action of floating icebergs, an
action which, according to the observations of Scoresby and others,
is fully adequate to remove from the Arctic to more temperate re-
gions great masses of earth and rock, and actually operates every
year in the manner stated to an incredible extent. Were the bed
of the ocean in which these icebergs, on melting, have deposited,
and continue to deposit, their rocky freight, to be now elevated above
the sea-level, it would present a striking resemblance to the so-called
diluvium. What further tends to confirm this theory is, that the
diluvium is often found to contain the remains of Mollusca, partly
of arctic origin ; and these are frequently in a state of perfect pre-
servation ; a fact which renders it probable that these remains have
not been removed to any great distance from their native habitat.

Mr. Harkness 0/2 Changes in the Temperature of the Earth. 145

The consequence of supposing numerous icebergs to have floated,
at a former period, into latitudes in which icebergs are never seen at
present, is, that the temperature of these regions and of the whole
earth at that period was lower than it is at present ; and the less
the distance to which the icebergs were floated from the glacier they
were originally launched from, the further must the then frigid have
encroached on the now temperate zone.

The erratic blocks which are found at various elevations on the
declivities of the Alps, and which sometimes form large mounds
placed transversely to those declivities, resemble in that respect the
morains formed by glaciers ; and hence it has been inferred that it
is by the action of glaciers that these alpine boulders have been
transferred to their present sites. Supposing that to have been the
case, the ancient glaciers must have extended to a much lower level
than the modern glaciers ; and the temperature of the Swiss valleys
must have been lower than it is at present. The glacier theory
therefore leads to the conclusion, that when these ancient morains
were formed there existed a frigid climate in the now temperate
zone.

There have been observed in many and very remote parts of the
world, at considerable elevations above the present sea-level, ex-
tending through great distances of country, long terraces of trans-
ported materials, such as sand, clay, and pebbles ; and these ten-aces
geologists have agreed in considering as the remains of ancient sea-
beaches. These beaches sometimes contain sea-shells, which belong
partly to arctic species.

In the great majority of instances these terraces are horizontal ;
and when that is the case, and more than one of these terraces form
continuous lines in the same district, they are all of course parallel
to one another. Brongniart, in the year 1829, was the first to call
attention to terraces of this description, the origin of which he attri-
buted to the subsidence of the waters of the ocean. This supposition
has by some geologists been considered as at variance with physical
probabilities ; and the more generally received hypothesis now is,
that these terraces owe their present position to elevation by subter-
ranean agency.

This explanation at first sight appears very probable; and the
more so as there are some ancient beaches which are not horizontal
but are inclined to the horizon. Of this description are the two
observed in Norway, between the 70th and 71st degrees of north
latitude, by Mons. Bravais ; of which the upper descends from its
summit level of 222 feet above the sea to its lowest level of .94 feet ;
and the lower descends from its summit level of 91 feet to its lowest
level of 46 feet. The present position of these Norwegian beaches is
probably owing to the same cause which has raised, and still con-
tinues to raise, a part of the Scandinavian peninsula above the level
of the ocean, and which has given rise to the ancient sea-beaches in
Sweden. It appears, howrever, from the discovery of a human ha-
bitation in connexion with these beaches in Sweden, that they be-
long, not to the post-tertiary, but to the historical epoch ; and it is

Phil. Mag. S. 3, Vol. 24. No. 157. Feb. 1844. L

146 Geological Society. Mr. Lyell on the

to the latter epoch, therefore, that we ought to refer the inclined
heaches observed in Norway by M. Bravais.

The fact that the post- tertiary sea-beaches are, in the great ma-
jority of instances, horizontal, strongly militates against the notion
that they owe their present position to elevation from beneath ; as
does also the fact of their wide-spread geographical distribution,
which is so extensive indeed as to be almost universal. Were we to
admit that wherever these beaches are found the land has been ele-
vated, we must admit that in the post-tertiary period the elevating
of the land was almost universal ; a conclusion in itself so impro-
bable, that we ought to seek to explain the difference of level between
the post-tertiarv beaches and the present ocean in some other manner.

The author then propounds a new theory to account for the post-
tertiary horizontal sea-beaches. This theory he bases on the above
stated conclusion, derived from the appearances which the diluvium
and the alpine boulders present ; namely, that during the post-ter-
tiary period the temperature of the earth was lower than it is at pre-
sent. From the observations of Kotzebue, Sabine and Scoresby, he
infers, that at the depth of about 800 fathoms from the surface the
temperature of sea water, whether near the equator or in high
latitudes, is not very remote from 40 degrees of Fahrenheit, the point
of temperature at which the density of fresh water is the greatest :
and as the mean depth, according to Laplace, of the Pacific Ocean
is about four miles, and of the Atlantic about three miles, and the
mean depth, therefore, of the two oceans about 3000 fathoms (of
which 800 fathoms is little more than a fourth part), he considers
that the mean temperature of the whole of the sea water taken to-
gether, is not far remote from 40 degrees. He infers from the ob-
servations made by Captain Sabine on sea water in high latitudes,
that sea water follows nearly the same law as fresh water in expand-
ing with a reduction of temperature below 40 degrees of Fahrenheit.
Hence he reasons, that if, during the post-tertiary period, the mean
temperature of the earth was lower, the mean temperature of the
sea was also lower than it is at present ; and this reduced tempera-
ture of the sea below 40 degrees would cause it to occupy a greater
volume than it now occupies, and consequently to rise on all the
sea coasts to a higher mean level than it now rises ; though not
exactly in proportion to its expansion, since it would then not only
be deeper but would occupy a greater surface than before.

The author seeks to account for the increase which he supposes
to have taken place in the mean temperature of the earth since the
po#t-tertiary period, by the extent of land within the tropics which
since that period has been raised from beneath the ocean by subter-
ranean agency, and which, since its upheaval, has been heated by
the sun's rays.

lie notices the fact, that in the south-west of Lancashire the dilu-
vium is found resting only upon level, and not on inclined surfaces.

May 10, 1843. — "On the Coal-formation of Nova Scotia, and on
the age and relative position of the Gypsum and accompanying
marine limestones." By Charles Lyell, Esq., F.G.S.. tic.

Coal-formation and Gypsum of Nova Scotia. 147

The stratified rocks of Nova Scotia, more ancient than the car-
boniferous, consist chiefly of nietamorphic clay-slate and quartzite,
their strike being nearly east and west. Towards their northern
limits these strata become less crystalline and contain fossils, some of
which Mr. Lyell identified with species of the upper Silurian group,
or with the Hamilton group of the New York geologists.

The remaining fossiliferous rocks, so far as they are yet known,
belong to the carboniferous group, and occupy extensive tracts in
the northern part of the peninsula, resting unconformably on the pre-
ceding series. They may be divided into two principal formations,
one of which comprises the productive coal-measures, agreeing pre-
cisely with those of Europe in lithological and palaeontological cha-
racter ; the other consists chiefly of red sandstone and red marl,
with subordinate beds of gypsum and marine limestone; but this
series is also occasionally associated with coal grits, shales, and thin
seams of coal.

A variety of opinions have been entertained respecting the true
age of the last mentioned, or gypsiferous formation ; and it is the
purport of this paper to show, first, that it belongs to the carboni-
ferous group ; secondly, that it occupies a lower position than the
productive coal-measures. These last are of vast thickness in Nova
Scotia, being largely developed in Cumberland county and near
Pictou, and recurring again at Sydney, in Cape Breton. In all these
places they contain shales, probably deposited in a freshwater
estuary, in which several species of Cypris and Modiola abound.
The plants of these coal-measures belong to the genera Catamites,
Stigmaria, Sigillaria, Lepidodendron, Pecopteris, Neuropteris,
Sphenopteris, Nceggerathia, Patmacites, Sternbergia, Sphenophyl-
tum, Asterophyllites and Trigonocarpum, with which are the trunks
and wood of coniferous and other trees. Upon the whole nearly 50
species of plants have been detected, more than two-thirds of which
are not distinguishable from European species, while the rest agree
generically with fossils of the coal formation in Europe.

The internal cylindrical axis of petrified wood in the Stigmaria of
Nova Scotia exhibits the same vascular structure, and the same
scalariform vessels, as the English specimens.

Mr. Lyell next describes the gypsiferous formation, especially the
marine limestones of Windsor, Horton, the cliffs bounding the estuary
of the Schubenacadie river, the district of Brookfield, and the cliffs
at the bridge crossing the Debert river, near Truro. Several species
of corals and shells are common to all these localities, and recur
in similar limestones in Cape Breton. In this assemblage of organic
remains we find a Crustacean intermediate between the Trilobite and
Limulus, Orthoceras (two species), Nautilus, Conularia, Encrinus,
Cyathophyllum, besides some species of the carboniferous limestone
of Europe, such as Euomphalus l&vis, Pileopsis vetttstus?, Avicula
mitiqua, Pecten plicatus, Isocardia unioniformis, Producta martini,
P. scotica ?, Terebratula elongata, Fenestella membranacea ?, Cerio-
pora spongites, Goldf. Eor assistance in determining these, the
author has been greatly indebted to M. de Verneuil.

L2

148 Geological Society.

The plants associated with these limestones consist of several
species of Lepidodendron, Catamites, and others agreeing with car-
boniferous forms. With these Mr. Lyell found in Horton Bluff
scales of a ganoid fish, and in the ripple-marked sandstones of the
same place, Mr. Logan discovered footsteps, which appeared to
Mr. Owen to belong to some unknown species of reptile, constitu-
ting the first indications of the reptilean class known in the carbo-
niferous rocks. Several of the shells and corals of this group have
been recognized by Messrs. Murchison and de Verneuil as identical
with fossils of the gypsiferous deposits of Perm in Russia, and it had
been successively proposed* to refer these gypsiferous beds of Nova
Scotia to the Trias, and to the period of the magnesian limestone.
That they are more ancient than both these formations, Mr. Lyell
infers not only from their fossils, but also from their occupying a
lower position than the productive coal-measnres of Nova Scotia and
Cape Breton. In proof of this inferiority of position three sections
are referred to, first, that of the coast of Cumberland, near Minudie,
where beds of red sandstone, gypsum and limestone, are seen dipping
southwards, or in a direction which would carry them under the pro-
ductive coal-measures of the South Joggins, which attain a thickness
of several miles.

Secondly, the section on the East river of Pictou, where the pro-
ductive coal-measures of the Albion mines repose on a formation of
red sandstone, including beds of limestone, in which Mr. J. Dawson
and the author found Producla martini, and other fossils common
to the gypsiferous rocks of Windsor, &c. Some of these limestones
are oolitic like those of Windsor, and gypsum occurs near the East
river, fourteen miles south of Pictou, so situated as to lead 10 the pre-
sumption that it is an integral part of the inferior red sandstone
groups.

Thirdly, in Cape Breton, according to information supplied by
Mr. Richard Brown, the gypsiferous formation occupies a consider-
able tract, consisting of red marl with gypsum and limestone. In
specimens of the latter Mr. Lyell finds the same fossils as those of
Windsor, &c. before mentioned. Near Sydney these gypsiferous
strata pass beneath a formation of sandstone more than 2000 feet
thick, upon which rest conformably the coal-measures of Sydney,
dipping to the north-east or seaward, and having a thickness of
2000 feet.

To illustrate the gypsiferous formation, the author gives a parti-
cular description of the cliff's bordering the Schubenacadie, for a
distance of fourteen miles from its mouth, to Fort Ellis, which he
examined in company with Mr. J. W. Dawson and Mr. Duncan.
The rocks here consist in great part of soft red marls, with subordi-
nate masses of crystalline gypsum and marine limestones, also three
large masses of red sandstone, coal-grits and shales. The strike of
the beds, like that at Windsor, is nearly east and west, and there are
numerous faults and flexures. The principal masses of gypsum do

* See Proceedings, vol. iii. p. 712, and vol- iv. p. 125 [or Phil. Mag. S.3.
vol. xxii. p. 71 and 545].

Dr. Gesner on the Geology of Nova Scotia, 149

not appear to fill rents, but form regular parts of the stratified series,
sometimes alternating with limestone and shale.

The author concludes by describing a newer and unconformable
red sandstone, without fossils, which is seen to rest on the edges of
the carboniferous strata on the Salmon river, six miles above Truro.

" A Geological Map of Nova Scotia, with an accompanying
Memoir," by Abraham Gesner, M.D., F.G.S., was presented to the
Society.

The surface of the province of Nova Scotia is for the most part
very uneven, much of it being traversed from south-west to north-
east by long parallel ridges of rock. The height of the hills seldom
exceeds 800 feet. The geology, as represented in Dr. Gesner's map,
is as follows : —

1. Granitic rocks. — The south-eastern coast of the peninsula pre-
sents an almost continual, though narrow band of granite, syenite,
and other granitic rocks. A second band of very unequal breadth
commences about the middle of the south-west coast of the penin-
sula, and ends near the course of the Ohio river. A third appears
in the isthmus forming the Cobequial mountain, a narrow ridge
extending from east to west. The granitic rocks of the province
frequently send off dykes and veins into the stratified rocks incum-
bent on them.

2. Stratified non-fossiliferous rocks. — A belt consisting of mica-
slate, hornblende slate, chlorite slate, greywacke slate, greywacke
and quartz rock, intervenes between the first and second of the above-
mentioned granitic bands. It is in the district occupied by these
older schistose rocks that the long parallel ridges, running from
south-west to north-east, are most clearly exhibited.

3. Silurian group. — The stratified non-fossiliferous rocks are suc-
ceeded by stratified fossiliferous clay slate, greywacke, and grey-
wacke slate. Fossils of a Silurian character occur in the latter. The
lowermost of these deposits, where they have ceased to afford organic
remains, may be regarded as Cambrian. A complete zone of Silurian
beds encircles and immediately covers the Cobequial granitic range.
The non-fossiliferous slates and the Silurian beds of the province
agree in the circumstance, that their strata dip away from the ad-
jacent ridges of granitic rock at angles of high elevation.

4. Old red sandstone, or Devonian group. — Above the Silurian beds
there occurs, in several parts of the province, a bright red micaceous
sandstone or conglomerate, accompanied by thin beds of red shale
and marly clay, and in some places containing seams of fibrous gyp-
sum. Hitherto no organic remains have been found in it. At Advo-
cate Harbour and on tlie Moose River this sandstone is seen lying
unconformably beneath the coal-measures. At the latter locality the
sandstone dips W. 21°, and the coal-measures dip N.N.E. 60°. It
is from a joint consideration of the mineral character of this forma-
tion, and its relative position as compared with the coal-measures,
that the author has regarded it as the equivalent of the old red sand-
stone.

5. Coal-measures. — Unless the calcareous deposits of the districts

150 Geological Society.

of Pictou and Stewiack should be found to belong to the carbonife-
rous limestone of New Brunswick and of Great Britain, the author
is not aware that there are any beds in the province which are refer-
rible to that formation. The coal-field which skirts nearly the whole
of the northern coast of Nova Scotia, and which occupies the greater
part of the isthmus, is a small part of that extensive coal-field of
which the remainder is situated in the province of New Brunswick.
In Nova Scotia, the commencement of the coal-field towards the east
is near Pomket Harbour, between the 45th and 46th parallels of north
latitude and the 61st and 62nd meridians of west longitude. Hence
it extends along the whole northern coast of the province of Nova
Scotia to Bay Verte, where it enters the province of New Brunswick.
The area of the coal-field in Nova Scotia is about 2500 square miles,
and that of the coal-field in New Brunswick about 7500 square
miles, making the total area of the coal-field in the two provinces
10,000 square miles, and in this computation is not included the
coal-field of Cape Breton. The above coal-field may therefore be
considered as one of the most extensive on the face of the globe, and
as of great value to Great Britain and her North American colonies.
The strata occupying this extensive area consist

1. Of gray, red and chocolate-coloured sandstones and conglome-
rates ;

2. Of red, blue and black shales ;

3. Of shelly limestones ;

4. Of clay ironstone ;

5. Of coal, of which the bituminous variety occurs throughout
the district.

All the strata abound in the remains of the plants that are usually
found in the coal-measures.

The coal-measures usually lie in long parallel troughs or in cir-
cular basins, towards the bottoms of which troughs or basins the
strata dip in opposite directions. The prevailing strike of the strata
is from south-west to north-east, which is also that of the more an-
cient slate rocks of Nova Scotia. The dip of the coal-measures varies
from 5° to 45°. Throughout the whole of the coast-line, from
Pomket Harbour to Point Miscou, the coal-measures undergo scarcely
any fault or dislocation.

From Pictou Harbour, in Northumberland Strait, a belt of coal-
measures, about six miles broad, runs in a westerly direction across
the isthmus, passing between the southern flank of the Cobequial
mountains and the southern coast of the isthmus, along the Basin of
Mines, and thence running further westward to Advocate Harbour.
The length of this belt is about 100 miles : the strata which compose
it rest along the northern margin of the great part of the belt, on
the fossiliferous slates of the Cobequial mountain ; it is along its
southern margin, that at Moose River and Advocate Harbour, the
coal strata rest unconformably on old red sandstone. At Moose
River the coal-measures contain a thin bed of marine limestone,
and like the old red sandstone which they rest upon, thin beds
of gypsum. The coal-measures lap round the eastern extremity,

Dr. Gesner on the Geology of Nova Scotia. 151

and pass along the northern flank of the fossiliferous slates of
the Cohequial range ; whence they pass nearly due west to Apple
River on Chignecto Bay. All the isthmus north of this line consists
of coal-measures.

The Nova Scotian or south-eastern coast of Chignecto Bay runs
nearly at right angles to the direction of the coal strata, and presents
an admirable section of them nearly thirty-five miles in length. Along
this length of coast the strata lie in a trough, the base or synclinal
point of which is Little Shoolie ; and from this point, as you recede
further in a north-eastern direction, the strata rise to the north and
north-north-west, with an increasing dip. At the Joggins, twelve
miles north-east of Little Shoolie, where the blue sandstone is ex-
tensively worked for grindstones, the dip is from 25° to 35°. In the
opposite direction, as you recede from the base of the trough, the
strata rise towards the south, until on approaching the intrusive
rocks of Cape Chignecto the inclination is 4 j°.

In making a careful examination of the entire of this coast of
thirty-five miles, only one fault was observed, and that occasioned
a dislocation of only a few feet. By measuring the horizontal di-
stances between the strata and making allowance for their inclination
at a number of places, the author estimated the total thickness of
the coal-measures on this coast at not less than three miles.

The chief part of the workable seams of coal is probably exposed
on the Chignecto shore, and it is near the middle of the section that
most coal-seams are seen. At the South Joggins, in the above coast-
section, in the horizontal distance of three quarters of a mile and in
a thickness of strata amounting to 1 800 feet, nineteen seams of coal
are seen, from six inches to four feet thick. Outcrops of coal have
been observed to the south-west of the Joggins, on the Apple River,
and to the north-east on the river Hebert ; also on the Macan River,
where one seam is ten feet thick and of good quality ; and also near
the river Philip. In the eastern part of the northern coast of the
province coal first appears at Pomket ; then at Fraser's mountain and
at the Albion mines, and other places near Pictou. In the belt of
coal-measures which lies south of the Cobequial mountain, two seams
of coal have been discovered in the forest, ten miles north of Truro,
dipping from that range. Outcrops of coal appear also in the same
belt at Jolly River, at Debert River, at Economy River, and at Parr's
Borough.

Along the northern coast which borders on Northumberland strait,
and along the courses of the rivers which fall into that strait, coal-
plants are very abundant. Among these are many large trees which
were branching at their tops. The bark is generally converted into
coal, and sometimes the whole trunk ; and then the woody fibre
remains very distinct. Several of these trees are four feet in dia-
meter, and some have been seen six feet in length. Along this
coast the trees are all prostrate, whether in the sandstones or shales,
and they do not appear to lie more in one direction than another.
On the coast of Chignecto Bay fossil trees also abound ; and in
most places they lie in all positions, parallel to the strata, or across

152 Geological Society.

them obliquely. They always increase in number in the proximity
of a seam of coal. In one part, however, of the Chignecto coast,
called South Joggins, where the nineteen seams of coal already
mentioned occur for the space of three-quarters of a mile, and in a
thickness of strata amounting to 1800 feet, the fossil trees which
occur are all perpendicular to the strata. In tracing these seams of
coal along the ravines to the distance of six miles from the coast,
trees have been observed in the same vertical position in respect of
the strata. The cliffs at this spot are from 80 to 100 feet in height,
and consist of grey and reddish sandstone, bituminous blue shale,
shelly limestone, clay ironstone and coal. The strata are rapidly
degraded, so that at every successive visit which the author has
made to the spot during the last ten years, he found that trees which
he had originally observed had disappeared, and that others were
exposed in their stead. At the last visit he made, which was in
July last, in company with Mr. Lyell, seventeen trees were exposed
to view, and this number was rather less than he had seen on former
occasions. The ordinary length of these trunks is from 10 to 30
feet, but some have been observed that were 50 or even 70 feet
long. They vary in diameter from 6 inches to 3 feet ; but one
was 4 feet 6 inches across. Most frequently their lower extremities
are situated in shale ; but sometimes they spring from the coal
itself, and when that is the case, they never pass through the seam
of coal. Sometimes their roots branch out into the shale or sand-
stone they rest upon.

At the place above referred to, ten miles north of Truro, the
strata above and below the coal abound in trunks, bi'anches, and
leaves of large fossil trees. The exterior of the trunks is coal ; and
the interior is usually sandstone and fine clay. In one tree the
whole trunk was coal, except a flattened portion resembling the pith
and extending through the centre of the tree from one extremity to
the other. At the spot on the Moose River, where the coal-mea-
sures rest on old red sandstone, a fossil tree 30 inches in diameter is
seen in black shale and dark-coloured sandstone.

Besides the coal district already described there is an area near
Falmouth and Windsor of seventy square miles, in which though
the coal has not been discovered, yet the ferns, Sligmaria, and other
fossil plants which the sandstones and shales of that area contain,
sufficiently establish the point that it belongs to the coal-measures.

6, New red sandstone. —At the Jolly and Debert Rivers the coal-
measures are overlaid by a red sandstone, associated with gj^psum
and limestone. In the districts of Windsor, Rawdon, and Douglas,
to the south of the Basin of Mines, and in that of Truro on the east
of that basin, a bright red micaceous sandstone prevails, alternating
with strata of red shale and indurated clay, and containing calca-
reous, gypseous, and red argillaceous marls. It is characterised by
containing thick beds of compact gypsum and limestone, and by its
being the seat of salt springs. The author regards it as agreeing
in geological position with the sandstone above-mentioned.

7. Intrusive Igneous Rocks, — The whole north-west coast of the

Intelligence and Miscellaneous Articles. 153

.peninsula next the Bay of Fundy, from Briers' Island to Cape Blow-
me-down, is one continuous narrow belt of trap, greenstone, and
amygdaloid. This belt is bounded to the south-east in its southern
part by St. Mary's Bay, and from the head of that bay to the Basin
of Mines, by the old red sandstone formation already described. The
trap overlies and pierces the sandstone at several points in its
course along the Bay of Fundy. At Cape Blow-me-down it forms
a perpendicular cliff 400 feet high, and rests on strata of sandstone.
If the axis of the Cobequial ridge be prolonged towards the west
until it meets the head of the Bay of Fundy, that axis, after pursuing
the Silurian zone which encircles the Cobequial granite, will enter
a trappean ridge composed principally of red felspar and porphyry,
about seven miles broad. The western extremity of the axis
on the Bay of Fundy is at Cape Chignecto, to the north-east of
which lies Chignecto Bay. The trap of Cape Chignecto is of two
varieties, the red and the green. The red contains several large
veins of sulphate of barytes. Near Shoolie, and at a place called
Cranberry Point, a conglomerate appears which consists of masses
of trap and of sandstone. It is near Apple River that the coal
strata, which extend to the north of this ridge of trap, come in con-
tact with it. The trap forms the axis from which the coal-measures
dip away until they become horizontal at Little Shoolie.

XXV. Intelligence and Miscellaneous Articles.

DETONATION OF THE ALLOY OF POTASSIUM AND ANTIMONY.

THIS alloy, as is well known, may be prepared by calcining the
potassio-tartrate of antimony. MM. Fordos and Gelis state, how-
ever, that when the mass has not been sufficiently heated and the
metallic alloy has not separated, a porous mass is obtained composed
of the alloy and charcoal, which detonates without being moistened,
and by the mere blow by which it is attempted to be separated from
the crucible ; the above-named chemists state that one of them was
wounded by the explosion which occurred with a mass of this alloy.
— Journ. dc Ph. et de Ch., Octobre 1843.

ON THE CHEMICAL CONSTITUTION OF WOLFRAM.
BY M. MARGUERITE.

Chemists are agreed as to the nature of the elements which are
contained in wolfram, but they appear to be ignorant of the degree
of oxidizement in which the tungsten exists. In a late sitting of
the Institute M. Pelouze stated the results of the experiments which
M. Marguerite had performed to determine this point.

Admitting, of which indeed no doubt can be entertained, that the
analyses of Vauquelin, Berzelius and Ebelmen are correct, the fol-
lowing formulas may be assigned to wolfram : —
1st. 3 Wo3 FeO, MnO Wo3.
2nd. 3 Wtto5 FeO3, MnO Wo3.
3rd. 4 (W2 O5) 3 (Fe2 O3) Mn2 O3.
The author decides in favour of the last formula, which represents

154- Intelligence and Miscellaneous Articles.

wolfram as a compound of blue oxide of tungsten and of two-
thirds oxide, of either iron or manganese. These oxides being iso-
morphous, if R represent iron or manganese, or a mixture of these
two metals, we arrive at the formula
WaOsR«03,
which will represent all the varieties of wolfram.

The first formula, which represents the tungsten as in the state of
tungstic acid and the iron in that of protoxide, is not admissible, for,
on one hand, cold hydrochloric acid separates pertoxide of iron from
the mineral and leaves blue oxide of tungsten, and on the other hand,
the free protoxide of iron reacts on the tungstic acid isolated and
reduces it to the state of blue oxide, and itself becomes peroxide.

When heated to ebullition in hydrochloric acid the blue oxide in
its turn reduces the salts of iron, and this reaction explains how
Berzelius and Ebelmen adopted the first formula.

The superior oxides of manganese convert the blue oxide into
tungstic acid under the same circumstances as the peroxide of iron,
even when cold. This circumstance induced the author to suppose
that the manganese might exist as the oxide Mn- O3, isomorphous
with the sesquioxide of iron, although found only in the state of
protoxide in the solution of the mineral.

M. Marguerite further observes that it is easy to explain the causes
of the different opinions which have been given on the chemical con-
stitution of wolfram ; that it had not been deduced from the very
exact analyses already alluded to, is because the last phase of an
operation was considered instead of its commencement.

M. Marguerite concludes that, —

1st. The tungsten in wolfram is in the state of blue oxide.

2nd. The iron is in the state of peroxide.

3rd. The tungstic acid and protoxide of iron obtained are the re-
sults of the analytic means employed, and that these two products
are eventually formed from each other.

4th. Of the three formulae which have been given, the second and
third only agree with experiments, and the second may be reduced
to Ws O5 R'203 .—Journ. de Ph. ct de Ch., Octobre 1843.

ANALYSIS OF ANCIENT AND FOSSIL BONES. BY MM. GIRARDIN
AND PREISSER.

The authors found that human bones taken from various ancient
tombs contained from less than one up to 8 per cent, of phosphate
of magnesia, and in one case the bones of an infant taken from a
Gallo-Roman tomb at Rouen, were found to be of a fine chrome-
green colour, and contained 3*1 per cent, of carbonate of copper, for
the existence of which no sufficient cause appeared.

In ancient buried bones, as well as in the fossil bones of animals,
the authors always found a much greater quantity of phosphate of
lime than in recent bones. Under certain unknown circumstances,
this salt suffers some curious modifications, by which it is converted
into, for the most part, sesquiphosphate of lime, which crystallizes in
small hexagonal prisms on the surface of the bones. This transfor-

Intelligence and Miscellaneous Articles. 155

raation is effected without either gain or loss of elements, and solely
by a simple change in the relation or the position of the elementary
atoms of the salt, so that the subphosphate of lime, the original com-
position of which is 8CaO, 3 P- O, is divided into two more per-
manent compounds, neutral phosphate and subsesquiphosphate, the
production of which is explained by the following equation :
8CaO, 3 P-' O5 = (2CaO, P2 O5) + 2 (3CaO, P* 0s).

It is very probable that it is the tendency of the subsesquiphos-
phate of lime to crystallize which occasions its formation. Many
facts prove the mobility of the elements of phosphate of lime, and
the property which it possesses of undergoing slight changes in its
constitution ; without these two circumstances, it could not, as
observed by Berzelius, perform the functions which render it so im-
portant in the animal and vegetable ceconomy. The crystals which
form on the surface of burnt bones are identical with the apatite of
mineralogists.

The authors were unable to detect the slightest trace of fluoride
of calcium in ancient human bones, whereas they always met with
it in fossil animal bones ; the existence of this salt in recent human
and animal bones is more than doubtful. MM. Berzelius and Mori-
chini are the only chemists who have stated its existence in recent
bones. Fourcroy and Vauquelin, Klaproth, Dr. Rees, and the au-
thors of this paper, were not able to detect it in fresh bones.

It follows from these introductory statements, that at any rate the
presence of fluoride of calcium, even if it ever exist in recent bones,
is accidental, and not constant, and that as this salt exists in all fos-
sil bones, it must necessarily have arisen by infiltration from without,
for neither mineralization nor fossilization has the power of creating
mineral substances.

When, therefore, fluoride of calcium is found in notable quantity
in any unknown bone, it may be considered as a fossil bone of an an-
tidiluvial animal, and not as a human bone. — Ann.de Ch.et de Phys.,
Novembre 1843.

ON APIIN. BY MONS. H. BRACONNOT.

This substance was discovered by M. Braconnot in attempting to
procure from parsley a volatile oil, or a distilled water, which might
be substituted for the fresh herb when out of season.

It is obtained abundantly and with the greatest facility by boiling
a sufficient quantity of the herb in water ; the boiling liquor strained
through linen, becomes on cooling a gelatinous mass, which resem-
bles pectic acid in appearance, and requires to be washed merely with
cold water.

The properties of apiin thus obtained are, that it is inodorous, in-
sipid and neutral ; by exposure to the air it dries without undergoing
any alteration ; after being pressed, dried, and reduced to powder, it
is of a yellowish-white colour. When heated it fuses, swells, and
blackens, but does not become more soluble in cold water ; if, after
thus acted on by heat, it is treated with boiling water, the portion

1 56 Intelligence and Miscellaneous Articles.

which is not charred dissolves in it, and on cooling a jelly is again
formed ; at a high temperature it hums with a large flame ; hy di-
stillation it yields an acid product.

Cold water scarcely acts upon gelatinous apiin, hut hoiling water
dissolves it readily ; the result is a yellowish limpid liquor, which on
cooling, or by the addition of cold water, becomes a transparent jelly.
Although gelatinous apiin is scarcely soluble in cold water, it never-
theless imparts a very light yellow colour to it, and the solution thus
formed by exposure to the air becomes eventually turbid ; protosul-
phate of iron is almost the only reagent which produces any effect
on this solution, but this detects the smallest traces of apiin, occa-
sioning a very intense blood-red colour ; five gallons of water, in
which about one-sixth of a grain of apiin is dissolved, is coloured red
by the addition of an equal quantity of protosulphate of iron.

Apiin is dissolved by boiling alcohol, and the solution becomes a
transparent jelly on cooling ; apiin, and especially when gelatinous,
is soluble in the weakest alkali, and yellowish solutions are formed,
which are precipitated by acids in colourless jellies ; when mixed with
lime a solution is obtained, which, when evaporated to dryness and
treated with water, yields a yellowish solution, from which acids pre-
cipitate a jelly ; and the same effect is produced by magnesia ; very
dilute solution of ammonia readily dissolves, but without appearing
to form a permanent compound with it ; bicarbonate of potash also
dissolves it ; caustic potash does not appear to alter apiin, though
long boiled with it, for it is precipitated again by acids in a jetyy.

Acids act very differently on apiin, causing it to undergo a modi-
fication which prevents it from gelatinizing ; if a little sulphuric acid
be added to a solution of apiin in boiling water, the* mixture remains
clear, but when it has been boiled for a few minutes, it becomes very
turbid, and is converted into a yellowish thick mass ; when this is
washed on a filter with cold water, a colourless acid liquor is ob-
tained, which, when saturated with chalk, yields a small quantity of
sugar, produced during the reaction ; the matter which remains on
the filter is slightly yellow after drying, and consists of nearly the
whole of the apiin employed, and as it is neutral to test papers, in-
soluble in cold water, and soluble in boiling water and alcohol, and
possesses the other properties of gelatinous apiin, excepting that in-
stead of being a transparent jelly, it is a white, clouded, opake sedi-
ment : still, when redissolved in boiling water, it produces with a
little sulphate of iron a blood-red flocky precipitate.

The flocky apiin thus obtained by sulphuric acid, may be regarded
as an isomeric modification of gelatinous apiin ; or rather, may not the
latter be the result of a combination of two substances, one which
unknown to us may have been converted into sugar by sulphuric acid,
whilst the other is apiin in its pure state ? M. Braconnot thinks the
latter the more probable supposition ; the property of gelatinizing
is also lost by boiling with oxalic acid, hydrochloric or concentrated
sulphuric acid.

Although apiin appears to contain but little or no azote, it neverthe-

Intelligence and Miscellaneous Articles. 157

-a

less furnishes, when treated with nitric acid, a large quantity of la-
mellar, brilliant crystals of picic acid, and only traces of oxalic acid.
When infusion of galls is added to gelatinous apiin, liquefied by
heat, no sensible change is produced, except that on cooling the mix-
ture solidifies into an opake white mass, which again liquefies by
heat. Chlorine gas, when passed into the gelatinous apiin, converts it
into a yellowish matter, which is insoluble in boiling water, but soluble
in alcohol and weak alkaline solutions ; there is also produced a small
quantity of carbazotic acid. It appears that apiin may be classed
with the substances composed of carbon, hydrogen and water, and
intermediate as to gums and resins. It may be supposed that apiin
exists in variable quantities on umbelliferous plants ; but M. Bra-
connot admits that he found very little in the leaves or stalks of
celery, and none in chervil. — Ann. de Ch. et de Ph., Octobre 1843.

ON SULPHOCAMPHORIC ACID. BY M. PHILIPPE WALTER.

Let a platina capsule be half filled with common sulphuric acid,
gradually add to it small portions of anhydrous camphoric acid
in very fine powder, stir the mixture continually, and the cam-
phoric acid dissolves, forming a perfectly limpid solution ; the sul-
phuric acid should be in considerable excess. Nordhausen and an-
hydrous sulphuric acid may be used instead of common ; but they
do not answer the purpose so conveniently.

If the mixture of the two acids be largely diluted with water, the
anhydrous camphoric acid being but slightly soluble in water, is en-
tirely precipitated, which proves that it is simply dissolved in the
sulphuric acid, and that this acid has not acted upon it.

If, however, the mixture be cautiously heated to between 105° and
120° F., the surface becomes covered with bubbles of gas, and at
150° the disengagement is rapid and considerable; on examination
it was found to be carbonic oxide free from sulphurous and carbonic
acid ; the heat was continued in a water-bath for about an hour,
when the mixture had assumed a brown tint. It was then largely di-
luted with water and suffered to remain one or more days, during
which the unaltered camphoric acid was deposited, and the solution
acquired a green colour owing to the formation of a new product.
The camphoric acid being separated by filtration, the green-coloured
solution is to be exposed in vacuo over a vessel containing sulphuric
acid, and in a day or two crystals of some hundredths of an inch in
length are formed, which are frequently of a green colour, so as to
give rise to suspicion of the presence of copper ; but it is derived
from the imperfect precipitation of the green colouring matter formed.
These crystals, after proper draining and pressure on filtering paper,
are to be dissolved in very strong alcohol, and the solution, by expo-
sure to spontaneous evaporation, yields crystals which are to be again
dissolved in water, and the solution, by evaporation over a water-
bath, yields colourless crystals, which are sulphocamphoric acid ;
these, after draining, are dried by exposure to the air.

This acid yielded by analysis, —

1 58 Intelligence and Miscellaneous Articles.

Equivs.

Carbon 37'82 or 9 = 54

Hydrogen .... 7-02 or 10 = 10

Sulphur 11-21 or 1 = 16

Oxygen 43-95 or 8 = 64

100- 744

These crystals appear, however, to contain three equivalents of
water, two of which they lose, as well as their form, by exposure to
sulphuric acid in vacuo, and also by heat, but the third equivalent is
lost only when the acid is combined with bases.

Anhydrous camphoric acid, as indeed also appears from the con-
stitution of the potash salt, must consist of

Nine equivalents of carbon . . 54
Seven . . . hydrogen . 7

One . . . sulphur . . 16

Five . . . oxygen . . 40

Equivalent .... 117

The properties of crystallized camphoric acid containing the three
equivalents of water are, that the form is that of six-sided prisms ;
they are colourless, their taste so very acid as to affect the teeth, and
extremely soluble in water. If small crystals be thrown on water
they dissolve almost instantaneously with rapid motion. The acid
containing one equivalent of water dissolves in water with still greater
rapidity and motion ; it is very insoluble in common or absolute al-
cohol ; soluble in aether, insoluble in cold oil of turpentine, and very
slightly dissolved by it when hot, and insoluble id sulphuret of carbon,
whether cold or hot. When the crystallized salt is heated on platina
it loses its water of crystallization, fuses, and becomes of a red co-
lour ; when more strongly heated it blackens, is completely decom-
posed, yielding abundant white vapours, and disappearing without
leaving any residue.

Nitric acid dissolves this substance slowly when cold ; when boil-
ing it dissolves it rapidly without decomposing it and without evol-
ving red vapours ; it is dissolved by cold, and more readily by hot, hy-
drochloric acid ; it has been shown by the method of preparation that
sulphocamphoric acid is soluble in sulphuric acid moderately heated ;
when cold it is but slightly so. When the sulphuric solution is rather
strongly heated it assumes at first a red tint, which on raising the
temperature becomes gradually black, and when the heat is raised to
ebullition the colour becomes of an intense black, the acid is decom-
posed, and sulphurous acid is evolved. When put into contact with
anhydrous sulphuric acid it loses water, becomes of a blood-red
colour and is decomjiosed.

When chlorine gas is passed into an aqueous solution of sulpho-
camphoric acid, an oleaginous compound is formed, which sinks to
the bottom of the vessel ; it is insoluble in water, and burns with the
green flame, which is characteristic of the presence of chlorine ; bro-
mine attacks it with the disengagement of white vapours of hydro-

Meteorological Observations. 159

bromic acid, and converts it into a body containing bromine, which
is heavier than water ; it is not acted upon by iodine when they are
triturated together.

It appears from M. Walter's experiments that anhydrous cam-
phoric acid is composed of

Ten equivalents of carbon 60

Seven . . . hydrogen .... 7
Three . . . oxygen 24

iT

and he considers that when this is acted upon by sulphuric acid, it
takes one equivalent of oxygen and yields one equivalent of carbon,
Avhich escape in combination as oxide of carbon, as already noticed ;
the sulphuric acid remaining combines with the camphoric acid, minus
the equivalent of carbon to form the sulphocamphoric acid.

M. Walter observes that the most remarkable character of the sul-
phocamphoric is this, that whereas in other acids formed by the re-
action of sulphuric on organic compounds, the sulphur exists in them
in the state of hyposulphuric acid, in this acid it is in that of sul-
phurous acid. — Ann. de Ch. et de Phys., Octobre 1843.

METEOROLOGICAL OBSERVATIONS FOR DECEMBER 1843.

Chiswick. — December 1. Overcast: clear. 2. Frosty haze : very fine: hazy.
3. Hazy : cloudy and mild. 4. Drizzly. 5. Cloudy and fine. 6. Clear and
tine. 7. Drizzly. 8. Very fine. 9. Foggy. 10. Foggy : fine. 11. Very fine.
12. Dense fog. 13. Foggy: hazy clouds. 14. Clear and fine. 15, 16. Fine,
with clouds. 17. Slight haze : clear and fine: foggy. 18. Foggy, 19, 20. Hazy.
21. Overcast. 22. Very fine : thickly overcast. 23. Cloudy and mild. 24. Clear
and fine. 25. Mazy : overcast. 26. Drizzly : foggy. 27. Hazy. 28. Cloudy
and fine : hazy. £9. Hazy. 30. Overcast: rain. 31. Cloudy: squally with
rain. — Mean temperature of the month 2-2G° above the average.

Boston. — Dec. 1. Cloudy. 2. Fine. 3. Fine, beautiful halo round the moon
eight o'clock p.m. 4. Fine. 5. Cloudy. 6. Fine. 7. Itain. 8. Fine. 9. Fine:
rain i>.m. 10. Foggy. II, 12. Cloudy. 13. Foggy. 14. Fine. 15. Fine:
rain early a.m. 10. Cloudy. 17. Fine. 18 — 20. Foggy. 21. Cloudy. 22 —

24. Fine. 25 — 28. Foggy. 29, 30. Cloudy. 31. Fine. — N.B. This is the
driest month since February 1832.

Stimlu-ick Manse, Orkney. — Dec. 1,2. Cloudy. 3. Drizzle. 4. Fine. 5,6.
Heavy showers. 7. Rain: showers. 8. Showers : clear. 9. Cloudy. 10,11.
Cloudy : clear. 12. Clear. 13. Cloudy. 14. Cloudy : heavy showers. 15,16.
Showers. 17. Drizzle. 18. Showers. 19. Cloudy : fine. 20. Fine. 21. Fine:
cloudy: fine. 22. Showers: fair: showers. 23. Showers: fair: damp. 24,

25. Clear i fair. 26. Damp : drizzle. 27. Clear : fine. 28. Clear. 29. Cloudy.
30. Hain : drizzle. 31. Showers: hail -showers.

ApjJegarlh Manse, Dumfries-shire. — Dec. 1. Hoar frost. 2. Thick fog. 3 — 7.
Showers. 8. Fair. 9. Fog and rain p.m. 10 — 13. Cloudy and rain. 14. Fair.
15. Slight shower. 16. Fair. 17. Fairandfine. 18. Fair though dull : shower
p.m. 19. Fair. 20. Showery. 21. Fair, but thick fog. 22. Very wet and
stormy. 23. Slight showers. 24. Slight showers a.m. 25. Showers. 26. Rain
p.m. 27. Fair, but cloudy. 28. Slight showers. 29, 30. Fair. 31. Rain.

Mean temperature of the month 46°-4

Mean temperature of December 1842 46 '05

Mean temperature of spring-water 46 •!

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THE
LONDON, EDINBURGH and DUBLIN

PHILOSOPHICAL MAGAZINE

AND

JOURNAL OF SCIENCE.

[THIRD SERIES.]

MARCH 1844.

XXVI. Further Observations on the Voltaic Decomposition of
Solutions. By Arthur Connell, Esq.*

\ FEW years ago I published a set of experiments on the
** galvanic decomposition of solutions of binary combina-
tions, such as acids or alkalies, in water and solvents contain-
ing water as a constituent-}-; and drew the general conclusion
that in such cases the water of the solvent alone suffers the
direct agency of the current. This rule of course did not in-
clude solutions of ordinary salts, in which the dissolved salt
was admitted to be resolved into its constituent acid and alkali
by direct voltaic action, at the same time that water was di-
rectly decomposed; but I stated that when an aqueous solu-
tion of certain metallic salts, such as sulphate of copper, was
made positive, and distilled water in a different vessel was made
negative by a power of fifty pairs of two-inch plates, the con-
nection being by asbestus, neither metal nor oxide was ob-
served to be formed, whilst on reversal of the battery reduced
metal immediately appeared on the negative foil now in the
solution of the salt, in virtue, as I conceived, of the reducing
action of nascent hydrogen arising from decomposed water.

This experiment was perfectly accurate with reference to
the circumstances under which it was made. About the same
time Professor Daniell varied those circumstances so as to
admit of a much more powerful voltaic agency, by using so-
lution of potash instead of distilled water, and separating this

* Communicated by the Author.

f Vol. xviii. of this Journal, S. 3. p. 241. It seems that it is not altogether
superfluous to state, that I did not hold in the memoir referred to, as has
been sometimes imagined, that water is the only compound body which is
decomposed by electrical agency. I spoke of solutions only, whilst every
body knows that Mr. Faraday has proved that many dry and fused oxides
and haloid salts are decomposed by the galvanic current.

Phil. Mag. S. 3. Vol. 24. No. 158. March 1844. M

162 Mr. Connell's further Observations on the

solution from that of the metallic salt by an animal membrane
only.

When in these circumstances the alkaline solution was
made negative and the solution of sulphate of copper positive
by twenty couples of a large constant battery, and a very ener-
getic action was thus produced, the membrane was found in
ten minutes to be coated with metallic copper, mixed with
black oxide of copper and blue hydrated oxide. This expe-
riment I have found to be perfectly correct, and have obtained
the result with a power of thirty-six pairs of four-inch plates
on Cruickshank's construction.

Shall we conclude then that the copper in such cases is a
product of the direct action of the current ? A little considera-
tion will, I think, show that this conclusion does not follow
so clearly or necessarily as may at first sight be supposed.
On this view the copper is travelling towards the negative pole
till it comes to the septum, in the pores of which it meets with
oxygen travelling in the opposite direction, and proceeding
from the other solution. A good deal of the copper combines
with this oxygen and forms the oxide we find on the membrane,
but a part of the metal does not succeed in effecting this union,
and is deposited in the metallic state, the equivalent oxygen
escaping. But can we not conceive, on the supposition that
water is undergoing direct decomposition on both sides of the
membrane, that the substance of that membrane may, in like
manner, present an obstacle to the union of the hydrogen and
oxygen travelling in opposite directions? and if any part of
the hydrogen fails in effecting this combination, it will of
course exercise a reducing action on the copper solution, just
as it would do at the pole itself. Thus then it may be doubted
whether the experiment affords any conclusive argument on
either side. If neither metal nor oxide appeared at the sep-
tum, this would indeed be decisive against direct electrolysis
of oxide or oxysulphion; but it may be doubted if the ob-
served appearances are conclusive as establishing such direct
decomposition.

A method occurred to me by which it might be possible to
get some additional light on this subject. It soon became
evident that the substance of the membranes is not the only
obstacle to the combination, whether of copper or of hydrogen,
with oxygen. The oxide of copper deposited on the septum
plainly increases this obstacle, not only by penetrating into its
pores, but by forming a layer on its surface ; and on exami-
ning some of the membranes after experiment, I noticed that
the copper was chiefly deposited on the outer surface of such
a layer of oxide. It therefore appeared that the best way to

Voltaic Decomposition of Solutions. 163

test the nature of the action would be to employ some solution
which would yield a matter capable, by deposition in the sub-
stance of the membrane, of increasing the obstacle, and would
likewise contain another matter which might be the subject of
a secondary agency, if it really was hydrogen which experi-
enced the difficulty in uniting with oxygen coming from the
other side of the septum. The salt which appeared to me to
offer these conditions was iodate of magnesia. If a solution
of it were substituted for sulphate of copper, then if magne-
sium were to be carried by direct agency towards the mem-
brane, we should of course simply expect that, as in the case
of sulphate of magnesia, a deposit of magnesia would take
place on the diaphragm, the affinity of magnesium for oxygen
being too strong to allow any of it to escape combination with
the oxygen coming in the opposite direction. On the other
hand, if water was the subject of direct decomposition, and if
from the contemporaneous decomposition of iodate of magnesia
into its constituent acid and alkaline earth and precipitation
of magnesia on the septum, an obstacle should be offered to
the whole of the hydrogen uniting with the whole of the oxygen
passing in the opposite direction, we should expect that the
portion of hydrogen escaping union would reduce iodic acid
at the septum, as it does when it reaches the pole immersed
in a solution of that acid or of one of its salts.

The arrangement I employed for the experiment was very
simple. A circular piece of bladder was cut rather larger than
a watch-glass, and a segment of this circle, somewhat larger
than the half, was moistened and made to adhere to a half of
the hollow surface of the watch-glass, a portion of it being at
the same time made to stand perpendicularly in the direction
of the diameter of the circle, so as to form a septum across it,
the remainder of the edge being bent over the outer edge of
the watch-glass so as to adhere to it, and the whole being then
allowed to dry. In this way, by pouring small quantities of
two liquids on each side of the central diaphragm, they could
be kept separate for a sufficient time to try voltaic action on
them ; it being found, however, that some fluids answered
better to be placed on the bladder-side and others on the other
division, so as to prevent subsequent mixing. When a dilute
solution of potash was placed on the bladder-side of the sep-
tum and a solution of sulphate of copper on the other, and
the former made negative and the latter positive by platinum
wires from thirty-six pairs of four-inch plates, the side of the
diaphragm towards the sulphate of copper was found in a
quarter of an hour or twenty minutes to exhibit metallic cop-
per lying on a dense layer of blue oxide of copper,

M 2

164- Mr. Connell on the Voltaic Decomposition of Solutions.

A solution of iodate of magnesia, obtained by saturating so-
lution of iodic acid with calcined magnesia with the aid of
heat, was mixed with starch solution and placed on the blad-
der-side of the septum, and a starch solution on the other side
of it; and the former made positive and the latter negative by
thirty- six pairs of four-inch plates. In three or four minutes
blue matter was observed beginning to be formed and soon
increasing considerably, being deposited on the positive side
of the diaphragm, and thence spreading into the liquid. None
whatever appeared on the negative side. When examined
after twenty minutes' action, the blue matter was found to be
mixed with magnesia. I conclude, therefore, that the whole of
the hydrogen arising from directly decomposed water did not
succeed in uniting with the oxygen coming in the opposite di-
rection from the other side of the diaphragm, and that the
obstacle to this union gradually increased as magnesia con-
tinued to be drawn towai'ds the diaphragm and to be depo-
sited in its pores, and ultimately on its surface. This hydro-
gen so escaping combination united in its nascent state with
the oxygen of iodic acid, and set the iodine free, producing
the usual blue compound with starch.

The nature of the action was still further illustrated when
solution of iodate of potash or of iodic acid was substituted for
that of iodate of magnesia, all other circumstances being the
same. With the first of these substances a mere trace of blue
matter appeared on the positive side of the diaphragm in a
quarter of an hour, and more on the other side ; and with the
second of them no blue was visible on either side in that time.
The explanation seems to be that a trifling obstacle is afforded
by the accumulation of a concentrated solution of potash in
the pores of the diaphragm on its positive side, to the union
of the hydrogen and oxygen passing in opposite directions,
where iodate of potash is acted on; whilst where iodic acid is
employed no substance is drawn towards the diaphragm, its
pores suffer no obstruction ; and no sufficient obstacle is af-
forded to the combination of hydrogen and oxygen so as to
produce any secondary action.

Some observations which were made in a different quarter*
on the experiments formerly detailed, will not occupy much
time in noticing them.

I argued that such substances as iodic acid and bromide of
iodine in solution were not directly decomposed, because when
positively electrified in connexion with negatively electrified
solution of starch, iodine did not pass towards the negative

* See observations of M. Poggendorffin the supplementary volume of
his Annalen, p. 590.

Mr. Binney on Fossil Trees near St. Helerts. 165

pole. On this it was observed1, that the iodine would form
iodic acid with the ox3'gen coming from the starch solution in
the opposite direction, and so not appear in a free state. I
answer, if so, why did not the iodine ultimately appear at the
negative pole, and there affect the starch, seeing that the
newly-formed iodic acid would be as liable to direct decom-
position as the original? Again, if bromide of iodine was di-
rectly decomposed, why was there effervescence at the -positive
pole, and why was not an orange compound of bromine and
starch formed at that pole ?

Analogous views are applicable to the decomposition of the
hydracids, and were formerly sufficiently explained*.

As to the observation on my argument for the solution of
haloid salts as hydracid salts, that the acid and alkali formed
in the circumstances mentioned f might have arisen from the
union of the elements of the haloid with those of water, it is
plain that this view assumes that haloid salts, supposing them
to be dissolved as such, are directly decomposed by the cur-
rent, whereas it was established by evidence of exactly the
same kind, as in regard to hydracids, that the electro- nega-
tive element appearing during their decomposition has a se-
condary origin. But further, supposing this had not been
established, on what grounds can we assume that if the haloid
is dissolved as such, and directly decomposed, the hydracid
supposed to be formed by the subsequent union of the elec-
tro-negative element with hydrogen shall not be equally di-
rectly decomposed ? and if so, how can we have any acid to
detect, far less a constantly accumulating quantity of it ?

St. Andrews, January 27, 1844.

XXVII. On the remarkable Fossil Trees lately discovered
near St. Helen's. By E. W, Binney, Secretary of the
Manchester Geological Society \.

PROBABLY no fossil plant has excited more discussion
among botanists than the Stigmaria. It is the most com-
mon of the whole number of plants found in the coal measures,
but there has hitherto been the greatest uncertainty as to its
real nature. In the Lancashire coal-field traces of it may be
found in every mine. It abounds in all the floors of the coals
unmixed with any other plants, and having the long stringy
fibrils hitherto considered as leaves radiating from the stem
in all directions, and often the fibrils alone are seen without

* See p. 246-7 of the memoir in this Journal above referred to.
t See p. 357, &c.

X Communicated by the Author; having been read before the Man-
chester Geological Society, October 26, 1843.

166 Mr. Binney on the remarkable Fossil Trees

the stem. On careful observation it is also to be found in the
upper and lower portions of most of the seams of coal, gene-
rally with its stringy appendages. It is also more rarely met
with in the roofs of coal mines and in sandstone rocks. The
specimens in the floors are by far the most numerous, and
they are frequently found to strike down from the lower part
of the coal into the clay underneath ; sometimes, where this
deposit is a thick one, at a considerable angle, and when it is
thin, nearly horizontal.

Among the many authors who have written on this plant,
probably no one has shown so accurate a knowledge of it as
Mr. Steinhauer. In an elaborate paper printed in the first
volume of the new series of the American Philosophical Trans-
actions, he describes the most perfect form of die fossil as that
of a cylinder more or less compressed, and generally flatter
on one side than the other. Frequently the flattened side
turns in so as to form a groove. The surface is marked in
quincuncial order with pustules, or rather depressed areolae,
with a rising in the middle, in the centre of which rising a
minute speck is often observable. From different modes and
degrees of compression, and probably from different states of
the original vegetable, these areolae assume very different ap-
pearances, sometimes running into indistinct rimae like the
bark of an aged willow ; sometimes, as in the shale impres-
sions, exhibiting little more than a neat sketch of the concen-
tric circles. He was of opinion that the fibrous processes,
acini, spines, or whatever else they might be called, were cy-
lindrical, and that small fragments of these cylinders showed
distinctly a central line of (pith?) coinciding with the point in
the centre of the pustule, and that some of these extended to
the length of twenty feet. He also notices the groove of the
cylinder being always under, and suggests that the pith had
fallen down from the centre ; and after further details he con-
cludes, "that the stem was a cylindrical stem or root growing
in a direction nearly horizontal in the soft mud at the bottom
of freshwater lakes or seas, without branches, but sending out
fibres from all sides; that it was furnished in the centre with
a pith of a structure different from the surrounding wood or
cellular substance, more dense and distinct at the older end
of the plant, and more similar to the external substance to-
wards the termination which continued to shoot ; and perhaps
that besides this central pith there were longitudinal fibres
proceeding through the plant like those of the roots of Pteris
aquilina. With respect to any stem arising from it, if a creep-
ing trunk, we have hardly ground for a supposition."

Messrs. Lindley and Hutton, after noticing at great length

lately discovered near St. Helen's. 167

Steinhauer's remarks in vol. i. p.106 of their Fossil Flora, come
to the following conclusions: — 1st. That the Stigmaria was a
prostrate land plant, the branches of which radiated regularly
from a common centre, and finally became forked; 2nd, that
it was a succulent plant; 3rd, that it was a dicotyledonous
plant; 4th, that the tubercles on the stem are the places from
which the leaves have fallen; 5th, that the leaves were succu-
lent and cylindrical. These authors, in their introductory
chapter of the second volume of their work, after stating that
they had seen two very perfect specimens found in the roof of
the Bensham seam of the Jarrow colliery, state that the centre
of the plant was a continuous homogeneous cup or dome, and
not the remains of the arms squeezed into a single mass, as
they had formerly surmised it might be ; and also that it was
not, as they before supposed, a land plant, but that it grew in
soft mud, most likely of still and shallow water, as they had
found its remains associated with an undescribed species of
Unio.

In the year 1839, in company with the Rev. Robert Wal-
lace, F.G.S. and Mr. Atkinson, I examined some upright spe-
cimens of the stems of Sigillaria reniformis found resting upon
a small seam of coal exposed in cutting the tunnel at Clay
Cross, on the North Midland Railway near Chesterfield. I
there distinctly traced a Stigmaria to the lower part of a Sigil-
laria; not being able positively to prove the absolute insertion
of one plant into the other, I was not able to pronounce with
certainty that they were portions of the same tree, but I was
convinced that Messrs. Lindley and Hutton had been mis-
taken in supposing that the Stigmaria was a domed or cup-
shaped plant, and that it had no upright stem. Accordingly,
in my paper read by me in 1840 on the Fossil Fishes of the
Pendleton Coal-field, at p. 178 in the first volume of the Trans-
actions of the Manchester Geological Society, I state that the
Stigmaria grew in water on rich mud, in a bay like the recent
mangrove of the tropics at the mouth of the Niger in the Brass
country. For the last four years I have examined a great
number of upright Sigillariae for the express purpose of acqui-
ring a correct knowledge of their roots.

Many practical colliers having seen upright stems of Sigil-
larias with part of their roots on small seams of coal only eight
to twelve inches in thickness, the floors of which were full of
root-like Stigmariae, very naturally concluded that the latter
were the roots of the former. M. Adolphe Brongniart has
lately announced that he supposed the Stigmaria would turn
out to be the root of the Sigillaria, from the great similarity in
their internal structure. Some geologists have also made si-

168 Mr. Binney on the remarkable Fossil Trees

milar guesses, but to my knowledge their opinions received
little consideration, owing to their not being able to bring any
facts in support of them.

The three fossil trees in the accompanying section, which
it is my intention to describe, were exposed to view during the
last summer in the White Grit Quarry belonging to Mr. Lit-
tler, at Scotch-row, near St. Helen's. They were met with in re-
moving the gray indurated silty clay, there known by the name
of * warren," a deposit nearly similar to many coal-floors, for
the purpose of working the sandstone lying under it. The
surface is covered with from six to eight feet of brownish co-
loured till, under which the warren containing the fossil trees
occurs. This latter deposit was exposed about seven yards
in thickness, and the white grit lying under the workmen in-
formed me was ten yards thick. The inclination of the strata
is to the east at an angle of about 23°. All the trees were at
right angles to the strata, and stood in a line nearly north and
south, about eight feet six inches above the grit rock, and con-
tinued upwards until cut off by the till.

Section of Mr. Littler's Quarry, near St. Helen's.
Surface.

Note. — This imperfect sketch is intended to give 'the reader merely an
idea of the position of the trees, and not to show their external characters.

The strata in which the fossils are met with occupy the

ft.

in.

2

0

1

0

0

9

0

6

1

0

0

0

1

11

0

0

lately discovered near St. Helen's, 169

lower part of the middle Lancashire coal-field, about 119
yards above the Rushey-park mine, the last thick seam in the
series, and between two beds of coal, the Sir Roger and a yard
mine.

By the kindness of my friend, Mr. John Hawkshead Talbot,
I am enabled to give the following section showing their posi-
tion : —

yds.

rCoal 0

Dirt 0

Sir Roger mine-^ Coal 0

Dirt . . 0

LCoal 0

Warren containing fossil trees . 17

Stone (white grit) 16

Coal and dirt 1

When I visited the place the trees had been exposed some
time, and hundreds of people had inspected them. They ap-
pear to have been the wonder of the neighbourhood, and ex-
cited not only considerable interest, but an unfair share of cu-
pidity. The proprietor of the quarry was anxious to preserve
them, and gave such orders to his servants ; but although placed
in a perpendicular wall of rock, parties provided with ladders
came during the night twice and stole portions of the roots.

Three specimens were originally standing in the quarry, but
the centre one has been removed. No. 1, the tree on the south
side of the quarry, is considerably the largest, and displays roots
which Nos. 2 and 3 did not do to an unpractised eye.

Both the gritstone rock and the indurated silty clay in which
the fossils were found afforded specimens of Lepidodendron,
Calamites, Pecopteris nervosa, a Neuropteris, and several other
coal plants.

The diameter of the largest specimen, No. 1, at the base is
about two feet nine inches, and at the top about one foot two
inches. Its height is now near seven feet*, but the workmen
informed me that two feet had been taken of the top, so that
it originally was about nine feet high. Scarcely one half of
the tree is exposed, the other half being still encased in the
matrix, in which it is imbedded. Four main roots have been
uncovered ; these evidently spring from the base of the tree in
pairs, like the roots of the trees found at Dixon Fold, on the
Manchester and Bolton Railway. Two of the roots had been
removed before I saw them, with the exception of about eight
inchesfrom their commencement, but the third I traced fourteen

* These dimensions are not from absolute admeasurement, there being
difficulties in the way which prevented me from taking such.

170 Mr. Binney on the remarkable Fossil Trees

inches, and the fourth about two feet. The workmen assured
me that they had measured the four roots full nine feet from
the stem. All the roots are coated with a slight covering of
bituminous coal, which adheres to the matrix in clearing them,
so that, they all appear decorticated. Their surfaces are of a
blackish colour, and marked with ribs and furrows which di-
verge on each side of lines which are parallel with the longi-
tudinal axis of the root, a peculiar character noticed by my
friend, the late Mr. Bowman, in the roots of the Dixon Fold
trees. Although the roots I examined were on the rise of the
strata, they struck down into the indurated clay at a greater
angle than those at Dixon Fold. The root on the south of
the stem was the one I first examined ; on inspection I noticed
the fibrils, so long considered as the leaves of the Stigmaria,
proceeding from it in all directions, but more numerously from
the under than the upper side. On looking at the matrix on
which the continuation of the root had laid, I found the areolae
with a little elevation in the centre, the convex corrugated
lines so common to large Stigmaria and the central pith, which
had evidently sunk down and formed a groove in the matrix.
The fibrils or radicles were all flat and showed something like
a central axis — some of them were measured — upwards of
three feet below the stem, and others, although not absolutely
proved to be continuous, could be traced eight and nine feet
down. Indeed, the whole of the shale lying between the base of
the tree and the top of the white rock was traversed by these
fibrils or radicles proceeding from the main roots. I did not
notice any entering into the rock itself. Immediately under, but
I could not see it join the tree, proceeded a stem like a tap-root,
about 2^ inches in diameter and inclining a little to the north;
it was about two feet long, but owing to my being able only
to examine the mould, I could not make out its characters.
The north root I carefully cleared from the matrix to the ex-
tent of near two feet, and found the radicles to proceed from
the main root in all directions, but stronger and more nume-
rously from the under side of it. In addition to these, I found
a circular tapering root of about an inch in diameter proceed-
ing in a straight line. I attempted to obtain a portion of the
root with the bark upon it, but I could not succeed, the coaly
envelope always adhering to the matrix and leaving the root
decorticated.

Notwithstanding that I carefully examined the stem of No.
1 four feet upwards, I could not distinguish the scars so ge-
nerally found on Sigillaria. The trunk was decorticated, with
the exception of some small specks of coal, and was marked
with irregular ribs, slightly convex, and parted by shallow and

lately discovered near St. Helen's. 171

narrow irregular furrows. Some of the ribs and furrows
divide and unite without order, and are made up of detached
portions having wavy and diagonal directions, which mix, be-
come faintly visible, and finally disappear. Impressions of the
ribs were taken on tracing-paper, and they exactly correspond
in character to those of the Dixon Fold trees.

No. 2 specimen had been removed from the quarry when
I first visited the place. The workmen informed me that they
had noticed no roots belonging to it. It is now lying in the
adjoining quarry in fragments, and appears to have been about
fifteen inches in diameter and nearly cylindrical. The interior
of it is composed of a very fine-grained hard stone, which,
although not what isgenerally called a sandstone, has more sand
in it than the matrix in which it was imbedded, and I did not
notice any internal cylinder so often met with in these upright
stems, but one of the sides presented a longitudinal depression.
The exterior exhibited the scars, ribs, and furrows generally
found on the Sigillaria reniformis so distinctly, that there
could be no doubt of its being one.

No. 3 is still standing in its original position in the quarry;
it appears to be about eight feet above the sandstone, and four
feet of it are exposed to view, the upper part being still covered
with clay. The base of it does not plainly show the main
roots like No. 1, but on cutting down the face of the clay
under it, although the roots had disappeared, I distinctly
traced the fibrils or radicles, similar to those of No. 1, radia-
ting from the centres, where the roots formerly were, in all
directions. From its exposed parts I take it to be about ten
inches in diameter ; it is decorticated, and seems to have been
cylindrical. I could not see very well-defined scars upon its
surface, but its ribs and furrows prove it to be a Sigillaria.

On examining the matrix near the stem I observed several
grass-like fibres, resembling the supposed leaves of the Lepi-
dodendron, running horizontally from it, but as I could not
distinctly trace their insertion, I will not take upon myself to
pronounce them leaves, although they were very like those
supposed to be such by my friend Mr. M. Dawes, F.G.S., in
one of his specimens now in the museum of the Manchester
Geological Society. At some future time, when the tree is
more exposed, I shall be able to give a more decided opinion
on this subject.

In conclusion I may state, that there is no question as to the
perfect identity of No. 1 specimen with No. 5 at Dixon Fold,
which the late Mr. Bowman, after a very careful examination,
pronounced to be a decorticated Sigillaria. I am aware that

172 Mr. Binney on the remarkable Fossil Trees

the correctness of this opinion of my late friend has been ques-
tioned by some eminent authorities nevertheless ; after having
examined many large specimens of upright Sigiilariae, I am
led to believe that the lower portions of very old trees, when
decorticated, do not exhibit those regular ribs, furrows, and
scars so characteristic of young specimens, and that he was
perfectly right in his supposition. No. 2, a lesser specimen
than No. 1, is an undoubted Sigillaria reniformis, but it gives
no more evidence of being allied to No. k than having been
found near it. No. 3 is also a Sigillaria, and the main roots
have almost disappeared, but its fibrils or radicles radiating
from the places formerly occupied by them, are most certainly
of the same kind as those of No. 1. Therefore, if similarity
of fibrils or radicles is any evidence of identity, No. 1 must be
decided to be a Sigillaria.

In addition to this I may state, that the upright stem before
described as found at Clay Cross, was an undoubted speci-
men of Sigillaria, and the root traced to it a Stigmaria.

Having thus described the upper portions of these trees, let
us now consider their extremities. With regard to the roots
of the specimens being Stigmarise, there might be a reasonable
ground to doubt it, if the fibrils were the only evidence of the
proposition ; but when we find that not only are the fibrils the
same, but the areolae and the central pith, in fact the whole of
the characters of the Stigmaria attached to the root, there can
scarce exist a doubt upon the subject.

The stems Nos. 1 and 3, being only partially exposed, have
not been examined for the purpose of noticing those concave
depressions so generally found in upright Sigiilariae, and which
Mr. Bowman suspected might have been made by some para-
sitical plant, but which it is probable were really caused by the
change in the position of a central woody axis. No. 2 displays
it, although the internal cylinder, which, by its removal from
the centre, caused the depression to take place, cannot now be
seen, as is generally the case, without breaking the specimen
vertically. These internal cylinders in the centre of upright
Sigiilariae have not been described with the attention that is due
to them, and cannot have escaped the attention of collectors.
They are not often to be seen in coarse sandstone casts, but
are rarely absent in those of indurated clay when carefully
looked for, and when the cylinders have not been filled up
with masses of leaves and other parts of plants. In a speci-
men of Sigillaria from Clay Cross, I have a cylinder with its
outside coated with carbonaceous matter and resembling the
cast of the exterior of the stem of a common calamite or E?ido-

lately discovered near St. Helen's. 173

genites striata, I cannot positively say which.* Now, although
it would not be safe to pronounce on a single specimen that
one of these hitherto supposed plants was an internal stem,
still, as we have seen that the Stigmaria and Sigillaria have so
long passed for distinct plants by the most eminent living bo-
tanists, we must not look to the opinions of men, however di-
stinguished, but rather trust to the collection of facts before
hazarding an opinion. The authors of the Fossil Flora, in
p. 24>, vol. iii. of that work, in describing the fossils of Burdie-
house, notice the rarity of Calamites, the almost entire absence
of Stigmaria, and that they did not find Sigillaria. In my own
experience I have always found Calamites associated with Si-
gillaria, and Stigmaria constantly present with them either in
the roof or floor.

The StigmariaorSigillaria,whichevernameis to be retained,
and probably the latter is the most proper, was a tree that un-
doubtedly grew in water, for the indurated silty clay in which
the specimens described in this paper occur was deposited
from that medium, and the position of the roots and radicles,
ramifying through the strata in all directions, prove that they
grew there, and preclude the possibility of their ever having
been transported to the place where they are now found. The
position too of the trees, placed as they are about midway be-
tween two seams of coal, 33 yds. 1 ft. 11 ins. distant from each
other, proves that, however gradually the bottom of the water
may have subsided, still that the trees grew and flourished,
notwithstanding that very considerable portions of the stems
were submerged in water. This singular position of large
trees is very interesting; physiological botanists will now
probably be enabled to throw some light on the functions of
those fibrous appendages which proceeded from the furrows
of the stems of Sigillariae, and which may have assisted to
nourish these most extraordinary trees.

* In this specimen the internal cylinder is the only vegetable matter in
the inside of the stem, and there can scarce be a probability of its having
been introduced, as is sometimes the case when Calamites are found mingled
with many other plants.

Transverse section
of stem.

[ 174]

XXVIII. On the Cause of Dissimilarity in the Phenomena
of the Ordinary and Voltaic Electric Fluids. By John
Goodman, M.R.C.S.L*
[" COMMENCED in the year 1840 a series of experiments
-*- on the identity of the fluids, voltaism and ordinary elec-
tricity. The conclusions at which I then arrived were detailed
in two papers read before the Royal Victoria Gallery of Man-
chester, and since published in the Annals of Electricity. My
attention was particularly directed to the subject of aqueous
decomposition, and the reasons why that produced by the or-
dinary electricity has failed to be identical with the voltaic in
the hands of the philosophers who have attempted the expe-
riments. After the many experiments which I have made in
this branch of the subject, both at that time and since, I find
that to effect decomposition it is necessary to make use of
platina poles of a magnitude in ratio *mith the quantity of fluid
circulating in the current; and to produce a pure elimination
of the gases, hydrogen at one pole and oxygen at the other,
the most material point to be attended to is the uniform, quiet
flowing of such current; that a perfect metallic union of all
parts of the circuit is necessary to prevent the occurrence of
accumulations (by solder or otherwise) ; that the oxide formed
upon copper wire, or even the lacquer upon other parts of the
apparatus, is sufficient to cause a break in the circuit, which
cannot be overcome without a given accumulation being ren-
dered necessary to overcome such break ; and that all accu-
mulations, from whatever source arising, as the sparks or col-
lections of fluid passing en masse from under the silken flap
to the receiving points, are sufficient to disturb the uniform
nature of the current, and to produce an admixture of the
gases by destroying the continually positive or negative con-
dition of the poles.

I here exhibited an apparatus employed for the decomposi-
tion of water by the frictional electricity. The poles are of
fine platina wire exposed about the y^th of an inch. With
this apparatus I have frequently effected decomposition of
water, by the current alone, from the electrical machine.

This experiment at once negatives the objections of Dr.
Faraday and other electricians to the analogy of this decom-
position with the voltaic "guarded poles" being no longer
employed.

The phaenomena exhibited by the ordinary and voltaic elec-
tricities are in many respects widely dissimilar. To the former

* Read before the members of the Manchester Institute of Natural and
Experimental Science, December 20, 1843 ; and now communicated by the
Author.

Mr. Goodman on the Dissimilarity of Electricities. 1 75

in its usual form at all times belong those attractive and repul-
sive properties which are displayed in the separation of the
gold leaves or pith-balls of an electroscope. In consequence
of the same it exhibits much elasticity of character and expan-
sive powers, great mechanical violence, momentum, and capa-
bility of resisting and opposing the pressure of the atmosphere,
and thus producing great passing distance and the appearance
of considerable magnitude of spark, &c. On the other hand,
the voltaic fluid produced by a single pair of plates exhibits
no sensibly attractive or repulsive properties, no mechanical
violence, &c. ; and so powerless is its current in opposing at-
mospheric pressure that it is incapable of exhibiting a single
spark, unless the plates are of considerable magnitude. Yet
with regard to quantity, the greatest amount of fluid which
could at any time be elicited from my electrical machine and
rendered available for decomposition of water (the most cer-
tain test of quantity), was calculated as equal to only 7jth of
the current produced by a voltaic pair formed of zinc and
copper wire y^th inch in diameter.

Now, although there exists this marked distinction between
the properties of the voltaic and ordinary electricities, there is
not in the English language a term in use by which any two
electricians can distinctly recognize the particular properties
of either fluid. There are indeed two terms which are pre-
cisely applicable to these conditions, viz. "tension and inten-
sity," but they are as yet used by electricians without any di-
stinction, and to express the same meaning. From their deri-
vation, however, tension from the verb tendo, to stretch or ex-
tend, and intensity from the preposition in and the same verb,
the application of the former to a stretching or extension out-
wards (which, as will shortly be seen, is the nature of the ordinary
electricity), to this condition the former may be very properly
applied. We have this term frequently applied in common
use to the stretching of a bowstring, the condition of a hoop
around a carriage wheel, that of the plates of a high-pressure
steam-boiler, or the cords of a musical instrument, to which
no one would for a moment think of applying the term " in-
tensity," whereas the latter, which is used commonly to denote
a state of being affected to a high degree, must be one to which
the condensation of quantity will be most fitly applicable.
We now come to the consideration, what is the cause, and in
what consists the difference between the voltaic and ordinary
electricities. The view which I have taken of the cause of
dissimilarity in the phaenomena of the two fluids is illustrated
in the employment of a condensing electrometer, or by the ac-
companying apparatus.

176 Mr. Goodman on the Cause of Dissimilarity in the

Before proceeding, I may name to you that Dr. Faraday
states, in his Experimental Researches in Electricity (1177),
that *' it is impossible experimentally to charge a portion of
matter with one electric force independently of the other;"
(1684) that "the terms free charge and dissimulated electricity
convey erroneous notions, if they are meant to imply any dif-
ference as to the mode or kind of action." " The charge upon
an insulated conductor in the middle of a room is in the same
relation to the walls of that room as the charge upon the inner
coating of a Leyden jar is to the outer coating of the same jar."
"The one is not more free or more dissimulated than the
other;" and (1170) " as yet no means of communicating elec-
tricity to a conductor, so as to place its particles in relation to
one electricity, and not at the same time to the other in exactly
equal amount, has been discovered."

In illustration of the two electrical states, let a metallic plate
A B, very smooth and with rounded edges, &c, supported by

A C

the insulating stand F, to which the pith -balls are attached
by the arm E, be charged with fluid from the prime conductor
of the electrical machine. The pith-balls will, as usual, di-
verge to a considerable extent. In order to prevent the trans-
mission of the charge through the atmosphere, the glass plate
U may be placed immediately in front of A B. Now bring
near the insulated metallic plate C D, or the metallic disc of
the condensing electrometer; and as the insulated plate ap-
proaches, the pith-balls or gold leaves of the electroscope will
be seen to collapse, until, when it has arrived at a given di-
stance, the former will be found in perfect apposition. Mark
also that before the approach of C D sparks of considerable
magnitude, equal to those from the machine itself, might be
obtained from the electrolyzed plate A B ; but when C D

Ordinary and Voltaic Electric Fluids. 1 77

arrives at the situation which produces the complete collapse
of the pith-balls, no spark can be obtained of even moderate
dimensions. When, although the quantity is much greater
than on the former instance, the length and even the diameter
of the spark is considerably diminished, remove the metallic
plate C D and the pith-balls will again diverge probably to as
great an extent as before; and by repeating the experiment,
the same results may be obtained under favourable circum-
stances for a considerable period. In this experiment the
pith-balls show the degree of what I denominate tension, which
at any time exists. We find also that as the plate CD ap-
proaches, the capacity for fluid is considerably augmented', that
when the plates are contiguous a large supply of fluid may be
added without producing any apparent or sensible effect; and
that in ratio with the contiguity of the plates so is the capa-
city. Hence may we infer, as stated by Dr. Faraday, "what
an enormous quantity of electric fluid is present in matter,"
their atomic particles being at all times subject to the polari-
zing influence of each other, and at inappreciable or atomic
distances, and inducing thus an amazing capacity for, and
condensation of, fluid.

In solution of the phenomena observable in the last expe-
riment, it will be found necessary to go back to the original
production of the fluid by the electrical machine. Upon the
first movement given to the cylinder by the friction of the
electric against the rubber, the positive condition of the cy-
linder and negative state of the rubber is universally admitted
to be the result. As long as these two surfaces remain in ap-
position the fluids are in a state of dissimulated or disguised
electricity, and no electrometer would be enabled to exhibit
any signs of electric action, although the quantity of fluid ac-
cumulated in each is the same as when separated. But as the
cylinder revolves, each portion, as it is rendered positive by the
action of the rubber, is carried to a considerable distance from
the same, and thus an entire removal of the one electrical
condition from its opposite state, or in other words, a separa-
tion of the antagonist forces is the consequence ; and it is after-
wards subject to polarizing influence only from remote bodies.
Now resulting from this separation of the forces a complete
suspension is given to their attractive influence upon each
other, polarizing influence being diminished according to the
square of the distances. The fluid thus set at liberty now
begins to exhibit the peculiar properties of "free" fluid or
ordinary electricity. The first and main peculiarity which it
manifests is the mutual repulsion of its own particles as a re-
sult of this repulsion ; we have the electrical particles separa-

Phil. Mag. S. 3. Vol. 24. No. 158. March 1844. N

178 Mr. Goodman on the Cause of Dissimilarity in the

ting from each other and from the interstitial spaces of the

elementary particles of the body, which there is every reason

Fig. ] . Fig. 2.

_ . . . ... Remote polarization.

Contiguous and proximate polarization. Fluid set " free."

Negative. Positive. Extension or expansion of

Result: condensation of fluid by attraction fluid by repulsion of similar
of dissimilar forces, or " intensity." force, or '• tension."

to believe voltaic fluid occupies, and at once spreading them-
selves upon the surface of the metal, stretching or expanding
to the utmost degree allowable by their affinity for the metal
and the pressure and non-conduction of the atmosphere, and
exhibiting their repulsive properties on other bodies, or the
phaenomena of electricity of "high tension." On the other
hand, let the naturally electrified particles of matter remain in
their usual proximity; let them be polarized to any amount;
let them be either the cushion and glass cylinder just described,
or the plates and fluid of voltaic apparatus, or any other kind
of matter whatsoever ; and so long as they remain in their
usual state of apposition and contiguity to each other, although
frequently some thousand times more fluid is in motion than
is produced by the electrical machine, not an evidence of ten-
sion or other sign of sensible electricity will be rendered evi-
dent by the electrometer, the attraction of the two forces for
each other being sufficient to neutralize their sensible action
with regard to all external matter, and to suppress their indi-
vidually repulsive powers. In consequence the increased
capacity for a future supply of fluid of the same kind in
the place of repulsion exhibited in the former instance,
evinces the disposition of the fluid to become more and
more condensed, and to assume that condition which may
with great propriety be termed "intensity." The electrical
condition of the cylinder after its removal from the rubber
is that which exhibits two positively electrolyzed surfaces.
This state I have denominated " unrelieved polarization."
Had a portion of fluid been removed from the internal

Ordinary and Voltaic Electric Fluids. 179

surface of the cylinder as rapidly as it was received on the
outer, as is the case in charging a Leyden jar, a very different
condition would have been the result, polarization would have
been complete throughout the whole thickness of the cylinder*.
It is this state of unrelieved polarization which is required at
all times to render electricity sensible; thus in subjecting a
tourmalin to the action of heat, or in the excitation of any
electric, the fracture of crystals, &c. &c. When electricity is
developed it is necessary that each opposing surface should
possess an electrical condition of the same kind, or no deve-
lopment of free electricity will ensue, and no attraction of
light bodies or other sensible effect will be produced. See figs.
1 and 2.

There is another kind of polarization alluded to in my
former papers, which increases tension in all modifications of
the electric fluid, which I have termed the " reciprocal " po-
larization. This occurs in all cases where one polarized body
is so placed in the vicinity of a second that the force which
each exerts shall mutually assist in exalting the electric con-
dition of the other. We have an exemplification of this power
exhibited in the experiment of the six jars described in my
former paper, where the discharge from the sixth to the first
will pass six times as far as from any single jar; also in the
combinations of a considerable number of pairs of plates in a
voltaic series, and in all magnetic and electro-magnetic phe-
nomena.

Concluding Observations.

That the tendency of all accumulations of electric fluid, in
obedience to the law of " universal equilibrium," is to become
dissipated and equally distributed amongst surrounding bodies,
which distribution is alone prevented by the interposition of
insulating media or electrics.

By the separation or removal of a duly insulated accumu-
lation from its opposing force it assumes the condition of "free
charge," and so long as no body or bodies of equal magnitude

* In charging a Leyden jar or battery, we find that so long as the charge
received within has force enough to continually render more and more
negative the outer coating, the two forces to a certain extent neutralize
each other j but so soon as this ceases, an electrometer (in connexion with
the internal) rises rapidly, and displays the augmentation of free fluid for
every spark which is added.

Fig. 1.
p n p n p n p n p p

OOOOOOOOOO free-
Fig. 2.

pnpnpnpnpn

OOOOOOOOOO neutral.

N2

180 Mr. Hen wood on the {Displacements) Heaves

are brought into its vicinity, either in an opposing electrical
condition, or capable of becoming so, such free charge conti-
nues to exhibit its usual phaenomena, and is at all times resi-
dent only upon the surface of matter.

On the occurrence of any body in the vicinity of the accu-
mulation of a sufficient magnitude, an amount ofjluid is dis-
placed from the latter in proportion to the contiguity of the
bodies ; and if the removal of force equals the accumulation, a
perfect polarization and neutralization with regard to all other
bodies of the primitive force is the result.

Unneutralized electric fluid is at all times " free," and ac-
cording to the distance of the opposing force is the extent of
freedom of the fluid.

XXIX. On the {Displacements) Heaves of Metalliferous Veins
by Cross-veins. (Part I.) By William Jory Henwood,
C.E., F.R.S., F.G.S.

TN practical geology there is no point of greater importance
■*- than the rediscovery of a metalliferous vein which has been
heaved by a cross- vein.

In the series of papers, of which this is the first, I will en-
deavour to submit the results of my inquiries on this subject
in the mines of Cornwall and Devon.

The result of every intersection must be either a simple
cutting through of one vein by the other, or a heave (displace-
ment). In the former case the portions of the intersected
vein occur exactly opposite to each other on either side of the
intersecting vein. In the latter this is not the case, but when
the traversing vein is approached along the course of one of
the severed parts, the other is found by turning towards the
right- or left-hand ; towards the greater or smaller angle.

(I.) Intersections of lodes affording different ores by eross-
veins. — I have observed 233 intersections, of which 50 are of
lodes yielding tin ores only, 59 of lodes in which the ores of
tin and copper occur together, and 124 of lodes affording
copper ore alone. 53 of these intersections are simple and
unattended by heaves', of the remainder, 119 are heaved to-
wards the right-hand and 61 towards the left: 150 to the
greater, and 30 to the smaller angle.

The relative proportions of the various phaenomena are as
follows, viz.

per cent.
Of all the lodes the proportion intersected but not

heaved is 22'7

OfthetinMtt J8'0

of Metalliferous Veins by Cross-veins. 181

per cent.

Of the lodes yielding both tin and copper ores . . . 37*2

... copper lodes 17*7

Of all the lodes the proportion heaved towards the right-

hand is 51»1

Of the tin lodes . . . . » 56'0

... lodes yielding both tin and copper ores . . . 44'0

... copper lodes 52*4

Of all the lodes the proportion heaved towards the left-
hand is 26*2

Of the tin lodes . 26'0

... lodes yielding both tin and copper ores . . . 18'6

... copper lodes 29*8

Of all the lodes the proportion heaved towards the greater

angle is 63*5

Of the tin lodes 52'0

... lodes yielding both tin and copper ores . . . 56*0

... copper lodes 74*2

Of all the lodes the proportion heaved towards the

smaller angle is . 12*9

Of the tin lodes 30*0

... lodes yielding both tin and copper ores . . . 6*8

copper lodes 8'8

The mean distance of the heaves feet.

Of all the lodes is 16*4

tin lodes 15*4

lodes yielding both tin and copper ores . . 14*6

copper lodes 17'5

Towards the right-hand 18*7

left-hand 12*0

greater angle 16*3

smaller angle 17*1

Gongo Soco Gold Mines, Brazil, W. J. HENWOOD.

October 5, 1843.

XXX. On the Determination of the Distance of a given point
on the Earth's Surface at, or very near, the level of the sea,
by observations on its depression from a known height above
it. By William Galbraith, Esq., F.R.A.S.

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

SHOULD the inclosed short paper meet with your appro-
bation, you will oblige me by giving it a place in your
Journal. It is intended as an improved solution of that pro-
blem in Horsburgh's edition of Mackenzie's Treatise on Marine

182 Mr. Galbraith on the Determination of Distances

Surveying, in which both the effects of curvature and refrac-
tion are neglected, that in considerable distances are indispen-
sable where even tolerable accuracy is required. I have oc-
casionally found it useful, and others may probably also find
it so.

I am, Gentlemen,

Your obedient Servant,
54 South Bridge, Edinburgh, WlLLlAM GALBRAITH.

December 28, 1843.

1 . Let BHF be a section of the earth, A B the given
height, the angle E A H, and B H the required distance.

In the triangle A B I right-angled at B, there are given
A B, the height of the point A above B, the earth's surface at
the mean level of the sea BHF, and the angle B A I, the
complement of the angle of depression E A H.

Now let the height be denoted by h
and the depression by D, then R : cot D
: : h : B I = cot D x //, a first approxi-
mation to the distance B H or K, the
chord in this instance nearly when not
great, or a small part of the distance of
the visible horizon only.

ButIBH = MHB=HFB=|HCB,
of which an approximate value may be
found from that of B I, when neither the
height nor distance is great. For this
purpose let g be the radius of the earth
as usual, R" an arc equal to the radius in
seconds, and A" the arc in seconds which measures the angle
HFB, then

R"
A" = — cot D . /i nearly (1.)

In the triangle A B H, the angle AHB = AIB = D — A".
Again, in the triangle A H B, sin A H B : sin H A B : : A B
: B H = K,
or K=cosecAHBsinHAB.AB = cosec(D— A")cosD.// (2.)

The effect of refraction is expressed by n K or 2 n A", n
being the coefficient of refraction, a quantity by which D must
be increased.

D - A" + 2 n A" = D - (1 - 2n A") = D - (0-5 - «)A".

Putting a" = (0-5 - n) A" . . , (x),

71

then 2rc A" = — a" = a" . . (7.) . . . (3.)

0*5 — n s ' v '

Substituting these in formula (2.), and it becomes

K - cosec (D - a") cos (D + «") h . . . . (4.)

by observations of their Depression. 183

It is obvious also that

a" = (0-5 - n) — K = (0-5 - n)/K, . . . (5.)

in which jT is the factor to convert feet on the earth's surface
into seconds of arc in any given direction.

2. Formula (1.) fails to determine A" with sufficient accu-
racy when the height h is considerable, and the distance K
extends to, or near to, the visible horizon.

In this case we may proceed as follows : —

B C : A C : : sin H A C : sin A H C = — sin H A C.

Whence 180° -(AHC + HAC) = HCA,
and £HCB = HFB = IBH = A".

Wherefore AIB-IBH = AHB;

g : g + h : : cos D : sin A H C = (l + — ) cos D . (6.)
But h being very small in comparison with g, 1 -\ exceeds

unity by a very small fraction, therefore log ( 1 H ) = — ,

in which /* is the logarithmic modulus. If g be taken equal to

the radius of the equator as a mean value, then log ( 1 -{ )

— 8*3171G78. Instead of the mean value of g being taken as
above,

logo = log R" — log /exactly . . . . (7.)

Hence log sine A H C = log cos D + — h . . . (8.)

always obtuse, of which in this problem its excess above 90°
is taken.

In the preceding formula it is supposed that the coefficient
of refraction, w, is determined by observation or calculation.
The mean value, however, amounting to 0'08 of the inter-
cepted arc, will frequently be sufficient. In this case the effect
will be 0*08 K, or 0*16 A", a quantity to be added to D while
A" must be subtracted.

Hence D - A" + 0-16 A" = D - 0*84 A" = D - a",
by making a" = 0*84 A".

Recurring to formula (1.), by substitution we have

log a" = const, log 7'6 170579 + log cotD + log^ . (9.)

But a" = —?— a" = !£?? a" = 0- 1 904-762 a" = \- a" nearly.
0'5 — n 0-42 5 '

184f Mr. Galbraith on the Determination of Distances

By combining this with the former, there results

first const, log 7*6170579 + log of 0*1904-762 = 6*8968986
= the second constant logarithm.

Hence

log a" = 1st const, log 7*6170579 + log K . (10.)
log a." = 2nd const.log 6-8968986 + log K, . (11.)
which two results being substituted in formula (4.), and the
operation repeated, will give K sufficiently correct, when the
distance is only a small, or even a moderate part of that of
the visible horizon.

In practice it will be found convenient and sufficiently ac-
curate to use the mean quantities in the first and second ap-
proximations, and the true quantities under given circum-
stances for the last approximation only.

3. Again, let the angle A H C be denoted by H, and sin H

= 2 sin £ H cos £ H = 2 sin ^ H (1 — sin2 \ H)*, therefore

2 sin £ H (1 - sin2 \ H)* = £™ cos D.
Squaring both sides, and there results

4 sin2 iH-4 sin4 | H = (*— ) cos2 D,
or, by arranging,

4 sin4 \ H - 4 sin2 iH=- {l±J^ cos2 D.
Add 1 to each side of the equation, and

4sin4^H-4sin2|H + I = 1 - (t±J^j cos2 D,

or 4sin4^H-4sin2£H + 1 = (l + ^—J cos D

x(l_L±i)cosD.

Multiplying and dividing by If- ) , and

4 sin4 $ H - 4 sin2 i H + 1

But = sec D/5 Dy being the depression of the horizon,

4sin4|H— 4sin2iH + 1 rrsec^/cosD^ cosD)(cosD/— cosD).
Since (cos D, + cos D) (cos D, — cos D) = sin(D + D,) sin(D — D,)
4sin4|H-4sin2±H + l=sec2I>y{sin (D + D,)sin(D-D,)}.

by observations of their Depression. 185

Extracting the square root, and there results
2sin2iH-l = ±secD/{sin(D + D/)sin(D-D/)}* . (12.)

2 sin2 I H = 1 ± sec D, {sin (D + Dy) sin (D - D,) }*, and

sin£H = {|(1 ±secD/[sin(D + D/)sin(D-D/)]*)}i . (13.)

From formula (16.) it appears that H — 90° = 2 sin2| H — 1,
the radius, or sin 90° being unity, therefore calling H — 90°
= d, we have

sin d m sec D, {sin (D + D,) sin (D - D,)}* . . (14.)
the most useful form, since d in this case is the arc required.
Remarks. — 1. If the negative sign in formula (13.) be em-
ployed, the resulting value of H will be the supplement of that
by the positive.

2. Since D is the depression of the given point, and D, that
of the horizon, D — D/ will then be the difference between the
depression of the given point D and that of the horizon D^,
which difference may be measured with a sextant or reflect-
ing circle, while the depression of the horizon may be com-
puted by the usual formulae ; and then D and D — J), become
known without an altitude circle on shore, as required in the
first method.

3. From the same figure the method of determining the
height above the level of the sea may be very readily derived.

Let H' be the visible horizon, the angle EAH' = D the
depression, A H' a tangent to the horizon at H' passing
through the point of observation A, and A B = h, the re-
quired height.

From the property of the circle E A H' = H' C A = 2 H'FD,
and H' F B m \ D. The triangles ABH',H'BF give

shUDicosD:: AB:BH' = AB x -^L
a sin I D

and

sinD:cos±D::BH':H'C = AB x COS]?COSf^
2 sin D sin £ D

= A B cot D cot J D.

Whence h = H' C tan D tan \ D = £ g tan2 D nearly . (15.)
Introducing the effects of refraction, n,

h = %g{l + w)2tan2D (16.)

or h = l§{l +n) sin2 l" D" = 0'5832 g sin2 1" D" (17.)
when the dip is expressed in seconds and n — 0'08,

const, log or log of 0-5832 g sin2 1" = 6'457582.

[ 186 ]

XXXI. Further Contributions to the Chemical History of the
Products of the Decomposition of Uric Acid. By William
Gregory, M.D., F.R.S.E*

TN 1840 I described, at the Glasgow Meeting of the British
-*- Association, an improved and very productive method of
preparing alloxan, murexide, &c. ; and I showed, from the
occurrence of urea among the products of the action of hy-
permanganate of potash on uric acid, that Liebig and Wohler's
view, according to which urea pre-exists in uric acid, must be
admitted, in the present state of our knowledge, as well-
founded ; thus giving additional probability to the supposition
of the existence of the acid supposed by them to be present
in uric acid, combined with urea, and called, hypothetically,
urilic acid = C8 N2 04.

Since that period I have been frequently occupied with the
subject of uric acid. In 1841, Professor Liebig having en-
trusted to me the treatment of upwards of 2 lbs. of urate of
ammonia, I extracted the uric acid from this, and converted
nearly the whole of it into alloxan, of which I obtained 1 ^ lb.
in large and absolutely pure crystals. This not only enabled
me to study the preparation of several of the other products,
but led me to economise as much as possible the very abun-
dant mother-liquid of the alloxan, which contained a large
quantity of that substance, but so much mixed with nitrate of
ammonia and free nitric acid, that the alloxan could not be
purified by crystallization, even if the liquid could have been
concentrated by heat without decomposition. I shall now
state the results of my experiments, as far as these are to-
lerably ascertained. There is still much to be done, and se-
veral investigations are in an imperfect state in my laboratory.
As it may be some time however before I may be able to re-
turn to them, I think it right, in the mean time, to describe
the results hitherto obtained. ,

1. Alloxantine.
This compound is best obtained from the mother-liquid of
alloxan, as prepared according to my process f. The acid
solution is diluted with two or three parts of water, and a cur-
rent of sulphuretted hydrogen gas is passed through as long
as it produces any effect. Sulphur is first deposited, and sub-
sequently a large quantity of alloxantine. The mixed pre-
cipitate is drained, washed with a little cold water, and then
boiled with water, acidulated with hydrochloric acid, until all

* Communicated by the Chemical Society j having been read November
7, 1843.
t See Turner's Chemistry, 7th edition.

Dr. Gregory on the Decomposition of Uric Acid. 187

the alloxantine is dissolved, which requires from a quarter to
half an hour, even when enough water is present for the final
solution of the whole. The solution is filtered while hot,
which takes place very rapidly, and deposits on cooling an
abundant crop of crystals of alloxantine. The quantity reaches
its maximum in twenty-four hours, and the amount retained
in the acidulous mother-liquor is but small. It may however
be obtained by concentration. By this method the mother-
liquid of the alloxan above mentioned, although some part of
it was used for other experiments, yielded upwards of 8 oz. of
pure alloxantine.

2. Dialurate of Ammonia.

This salt may be also obtained in abundance from the
mother-liquid of alloxan, as well as from that of alloxantine.
Ammonia is to be cautiously added in the cold, so as to leave
a slight excess of acid, and hydrosulphuret of ammonia is to
be then added in excess, so as to redissolve any sulphur that
may be at first thrown down. The dialurate is formed in the
cold so abundantly as to cause the whole to become thick. It
may be dissolved in the liquid by the aid of heat, and it is
then deposited on cooling in crystals. We ought to see that
nothing is left undissolved by the hot liquid ; should this oc-
cur it is probably owing to sulphur, and in that case a little
hydrosulphuret of ammonia clears all up. The crystallized
dialurate of ammonia is collected on a filter and washed, at
first with a weak solution of hydrosulphuret of ammonia, then
with alcohol, to which enough hydrosulphuret has been added
to give it a pale yellow colour, and finally with pure alcohol
till the latter passes through quite colourless and pure. The
salt is quickly submitted, while still on the filter, to pressure
between folds of bibulous paper, and is finally dried in vacuo
over sulphuric acid. Should it not appear pure, the process
of dissolving it in water with the addition of hydrosulphuret
of ammonia, of crystallizing, and washing as above, is to be
repeated. By this method I have prepared this salt in large
quantity, and have obtained it dry and quite pure, with only
a faint tinge of flesh colour, in fact almost colourless. If dried
in the air, without the use of the alcohol and hydrosulphuret
in washing, and with the aid even of a gentle heat, it becomes
blood-red.

The pure dialurate forms minute prismatic crystals, which
are united together when dried in light bulky masses of a
faint silky lustre. I took advantage of the possession of a
large stock of this salt to repeat the analysis of it, determining
the nitrogen by the process of Varrentrapp and Will. Se-
veral analyses made by myself, and one made by Mr. Keller,

188 Dr. Gregory on the

yielded results which I shall not detain the Society by re-
peating, as they agreed entirely with those of Liebig and
Wohler.

3. Dialuric Acid.

Liebig and Wohler failed to obtain this acid in a separate
form, owing doubtless to iheir being compelled to make their
experiments on very small quantities. I found that it is easily
obtained when the preceding salt is dissolved, with the aid of
heat, in an excess of diluted hydrochloric acid. The liquid
deposits on cooling a quantity of sparingly soluble crystals,
not unlike those of alloxantine, yet quite distinguishable from
them; these crystals are dialuric acid. They have a strong
acid reaction, and readily neutralize the alkaline bases, form-
ing, with ammonia, the preceding salt; with potash, a spa-
ringly soluble salt in hard crystals; and with baryta an inso-
luble or very slightly soluble powder. The latter salts are
formed when dialuric acid is added to solutions of the soluble
salts of potash and baryta, so that the affinities of the acid are
powerful.

Dialuric acid is not however very permanent in its uncom-
bined form, that is to say, when dissolved in water. It gra-
dually passes into alloxantine when exposed to the air, oxy-
gen, no doubt, being absorbed. The change may be traced
in the colour of the precipitate produced by barytic water.
If it be white, the acid has not yet undergone a change ; but
if it be pale pink, reddish-purple, or violet, this indicates the
gradually increasing proportion of alloxantine. Even the
crystals of dialuric acid, when left in the liquid from which
they have been deposited for a day or two, are found to be
partially changed into alloxantine.

I made several analyses, both of the acid itself and of its
compounds, with potash and baryta. The details shall appear
hereafter : at present I may state that these analyses corre-
spond to the hypothetical formula given by Liebig and Wohler,
namely C8 N2 H4 Os = C8 N2 H3 07 + HO, in which HO
seems to be capable of replacement by MO in the salts. It is
important to observe that urile or urilic acid, C8 N2 04 + H4
04, = 4< atoms of water, contains the elements of dialuric acid.

It is proper to state that Liebig and Wohler did obtain by
the same process as I adopted the crystals of dialuric acid,
which, however, appear to have been partially converted into
alloxantine before they were examined*. Indeed my experi-
ments lead me to believe that the substance described by these
chemists as dimorphous alloxantine is nothing but dialuric
acid, more or less completely converted into alloxantine, and
* Ann. der Pharm., xxyj, 280.

Products of the Decomposition of Uric Acid. 189

retaining probably its original form. Or they may have exa-
mined a mixture of the crystals of both, in which those of
dialuric acid happened to be the largest and best formed.
Such a mixture, if analysed, would of course yield results
closely approximating to those derived from alloxantine, as
the latter body consists of the same elements as dialuric acid
+ 1 at. of hydrogen and 2 at. of oxygen only. Liebig and
Wohler have already observed, and my experiments confirm
the statement, that the liquid obtained by boiling dialurate of
ammonia with an acid, deposits, when allowed to stand for
some time after cooling, crystals of alloxantine, which will of
course be found mixed with the dialuric acid deposited during
refrigeration, unless the latter be first separated.

The salts of dialuric acid in the dry state are quite perma-
nent. I am still occupied with the study of this remarkable
acid and its salts.

4. Acid Thionurate of Ammonia.

This salt, from which, according to Liebig and Wohler,
the uramilic acid is best obtained, may be prepared in any
quantity by dissolving the neutral thionurate of ammonia in
hot water, and adding exactly as much hydrochloric acid,
calculated from the specific gravity by means of the published
tables of liquid hydrochloric acid, as corresponds to 1 eq. of
hydrochloric acid for 1 eq. of the salt, which contains 2 eq. of
ammonia. One of these is removed by the hydrochloric acid,
and when the liquid is gently evaporated to a small bulk it
deposits the acid (monobasic) thionurate of ammonia in soft
crusts, which frequently fall to the bottom, and are composed
of very minute prisms. I have not yet succeeded in obtaining
uramilic acid either from this salt or in any other way; and
Prof. Liebig informs me, that neither he nor Prof. Wohler
has been so fortunate as to succeed in procuring it again. It
can hardly be doubted, however, that with an easy and sure
method of preparing the acid thionurate, we shall soon ascer-
tain all the conditions essential to the formation of uramilic
acid. The acid thionurate itself, as well as all the compounds
now mentioned, I have prepared by ounces at a time without
once failing.

5. Alloxano- sidphurous Acid.

Liebig and Wohler mention that a solution of alloxan in
sulphurous acid, when slowly evaporated, deposited large ta-
bular acid crystals, which not only were not thionuric acid
(which requires the elements of ammonia besides those of al-
loxan and sulphurous acid), but, when mixed with ammonia,
did not produce the thionurate of that base but a totally dif-

190 Dr. Gregory on the Decomposition of Uric Acid.

ferent salt, of a gelatinous aspect, which has not been further
examined. I have not examined those tabular crystals, nor,
indeed, have I as yet seen them ; but I have by other means
obtained a salt, the acid of which appears to be composed of
alloxan and sulphurous acid.

To obtain this salt, dissolve alloxan in the smallest possible
quantity of cold water, and add to the solution a slight excess
of a saturated solution of sulphurous acid in water. Then
add, with care, caustic potash in solution till there is the
slightest possible alkaline reaction. There will be deposited
very soon, partly even at once, in the cold solution a salt in
hard brilliant crystals, which may easily be obtained, by re-
crystallization, of considerable size, and are very beautiful,
from their perfect whiteness, their transparency and brilliant
lustre. This new salt may be procured in any quantity and
with the utmost facility. I have not yet succeeded in isolating
the acid, but the analysis of the salt indicates that the acid
consists of two atoms of sulphurous acid and one of alloxan.
It thus differs from thionuric acid by the absence of 1 eq. am-
monia, and probably also in being monobasic, while thionuric
acid is bibasic. The analytical details concerning this new
acid, which I propose to call the alloxano-sulphurous, will
appear when I have completed my investigation of its pro-
perties. It is probable that the large tabular crystals above
mentioned, as obtained by Liebig and Wohler, are nothing
more than the alloxano-sulphurous acid in a free state.

6. Alloxanic Acid.

When pure alloxantine is dissolved in distilled water, and
the cold solution allowed to stand, it slowly loses the property
of giving a violet precipitate with barytic water, and finally
yields a white precipitate.

The liquid is now acid, and if gently evaporated to dryness
yields crystals, which are very soluble both in water and al-
cohol, and which possess all the chemical characters of allox-
anic acid. Professor Liebig did me the favour to examine
these crystals as obtained by me, and considered them to be
alloxanic acid, as I had previously done. I did not consider
them pure enough for analysis, and besides their analysis
could throw little light on the subject, as the crystallized al-
loxanic acid has the same composition in 100 parts as anhy-
drous alloxan; and differs, therefore, from alloxantine only
by containing 1 eq. of hydrogen less.

Should this observation be confirmed, it seems difficult to
account for the production of alloxanic acid in this experiment.
No other compound appears to be formed, and the change

Mr. W. H. Balmain on JEthogen. 191

seems to take place as well in tightly corked and filled vessels
as in the air. Besides, when alloxantine is oxidized, it yields,
not alloxanic acid but alloxan, and there is no base present
that might be supposed to give rise to the production of the
acid.

It is possible that this acid may not be really alloxanic
acid, although agreeing with it in its reactions. In that case
it appears most probable that it may be isomeric with allox-
antine, as alloxanic acid is with alloxan. At all events, it is
impossible to see how the 1 eq. of hydrogen has been removed,
if the acid be really the alloxanic. I am still engaged in re-
searches on this part of the subject, the results of which I
shall forward to the Society at a future period, along with
those of the other investigations briefly described above. The
study of the products of the decomposition of uric acid is still
very far from being completed, and I hope, at no very distant
period, to follow up this paper with another on the same
subject.

XXXII. Additional Observations on Ailtliogen.
By W. H. Balmain, Esq.*
/^\N proceeding to make some quantitative experiments on
^-^ sethogen, I found, that through depending too much upon
simple change of property, I had been misled upon some
points ; and I take this, the earliest, opportunity of pointing
out in what respects my conclusions were erroneous.

All the compounds described as aethonides are one and the
same substance, a new compound of boron and nitrogen, pro-
bably formed by the decomposition of the aethonide of the
metal by the nitro-muriatic acid used at the end of the pro-
cess. It would appear that there are two compounds of boron
and nitrogen ; one, which is not altered by exposure to a
white heat, is decomposed by the action of water at ordinary
temperatures, and also by the action of nitric acid, and which
does not phosphoresce before the blowpipe; and a second,
which is not decomposed by any reagents, with the exception
of water and oxygen at a high temperature, and which phos-
phoresces beautifully before the blowpipe. The first is
formed when mellon and boracic acid are heated together
and combines with the metals ; the second whenever a com-
pound of the first with a metal is decomposed by abstraction
of the metal, which is effected with such difficulty, that the
traces left induced me to suppose that it was an essential ele-

* Communicated by the Chemical Society ; having been read November
7, 1843. The author's former paper will be found in Phil. Mag. S. 3.
vol. xxii. p. 467.

192 Mr. Drach on the Enumeration of Prime Numbers.

merit of the compound. Whether or not these two com-
pounds are isomeric, remains yet to be ascertained.

The simplest method of preparing the phosphorescent com-
pound is to heat together 12 parts of cyanide of mercury, 1^
of boracic acid, and 1 of sulphur.

The compound of phosphorus and nitrogen (discovered
by Rose) probably has similar relations, and may rJtrhaps be
studied to advantage in connexion with the above ; an easy
method of preparing it is to place some chloro-amidide of
mercury in a flask, and add from time to time a portion of
phosphorus, keeping up a gentle heat all the time, and agi-
tating now and then ; and when the phosphorus ceases to pro-
duce any decomposition, raise the temperature nearly to red-
ness.

XXXIII. On the Empirical Law in the Enumeration of Prime
Numbers. By S. M. Drach, F.R.A.S.

EGENDRE gives, in his Thcor. des Nomb., p. 395, the
-*-i following approximate theorem for the number y of
primes in a given limit x : —

y = x-*- {hyp. log. a? — 1-08366}.
This is successively reducible to

g% m x -s- 2-95548 j and e* = ('338355 .v)* .

The former equation shows that the limit, and its ratio to
the number of containing primes, are respectively the abscissa
and ordinate of a logarithmic curve. According to the learned
author of the article Primes, in the Pen. Cyc, anno 1841, the
deduction of the constant quantity 1*08366 is as yet unknown.

As however it = 3*14159, &c, and its powers, in conjunc-
tion with a finite and generally simple fraction, represent the
sums of so many series of whole numbers, it seemed probable
that the aforesaid constant was somewhat connected with it;

5 /—
and in fact — v it = 2*95482 has for its hyp. log. 1*0831904,
3

differing little from the former. This difference is insensible
for small values of x, only whole numbers being required, and
with the increase of the value of x the constant becomes a pro-
portionally less fraction of hyp. log. x.

The annexed table gives the actual number of primes, P,
from 10,000 to a million; the third column is the excess
of Legend re's y above P; and the fourth presents the similar

quantity, 3/1 assuming — - Viz as the constant. The total re-
sulting errors are for column 3, 191 —68 =123, and for co-

Dr. A. W. Hofman on Bases in Coal-gas Naphtha. 193

lumn4, 173 — 80 = 93; thus my supposition confines the errors
on the greater or positive side within narrower limits.

The constant deduced from each limit separately varies be-
tween 1 '063983 and 1 '129124 after no apparent law; the
arithmetical means are 1*0875431050,000, 1*085334 to 100,000,
1-082687 to 500,000, and 1*081956 to 1,000,000, indicating
an average decrease.

It is likewise known that — V% = / e~ dt, t being any

number; .*. we obtain this form:

xe

'2 /, 10

dt = — <

1000*2.

p.

y-v.

i/'-p.

10

1230

+ 1

+ o

20

2263

-4- 5

+ 4

30

3268

-16

— 16

40

9204

+ 1

+ 1

50
60

5134

+ 2

+ 1

6058

- 9

— 9

70

6936

+ 14

+ 13

80

7837

+ 1

+ 1

90

8713

+ 5

+ 4

I DO

9592

— 4

— 4

150

13849

— 5

— 5

200

17984

-12

— 3

250

22045

— 10

— 11

300

25988

+ 36

+ 35

350

29977

— 16

-18

400

33861

- 7

- 9

500

41538

— 5

- 7

600

49093

+ 13

+ 11

700

56535

+34

+ 32

800

63937

+ 18

+ 16

.900

71268

+ 11

-1- 8

1000

78493

+ 50

+47

London, January 29, 1844.

8. M. D.

XXXIV. A Chemical Investigation of the Organic Bases con-
tained in Coal-Gas Naphtha. By Dr. Augustus William
Hofman, Assistant in the Giessen Laboratory.
[Continued from p. 128.]
Combinations of Cyanol.
7V[ ONE of the other organic bases afford crystallizable com-
■^ pounds with such facility as cyanol. In this respect the
perfectly pure base differs from that mixed with the smelling
Phil. Mag. S. 3. Vol. 24. No. 1 58 . March 1 844. O

194- Dr. A. W. Hofman on the Organic Bases

matters; for, while the latter does not crystallize with certain
acids, the former instantly produces a white crystalline mass
on being brought in contact with them. By recrystallization
from alcohol or boiling water, beautiful inodorous crystals of
these salts may be obtained, nearly all of which, when first
prepared, are white; but on exposure to the air, particularly
in a moist state, become rapidly rose-red. Combinations of
cyanol with acids possess the character of true salts, they are
capable of undergoing double decomposition, and their forma-
tion is attended with evolution of heat.

The high saturating capacity of this base is remarkable; its
atomic weight (1174*6) is next to that of nicotine (1035*4),
which is the smallest of all the organic bases.

The salts of cyanol are decomposed with facility by the al-
kalies, the base separating in colourless globules. This change
is also effected by ammonia.

At a boiling temperature cyanol however displaces ammo-
nia from its combinations, evidently owing to the greater vola-
tility of the latter.

Cyanol combines directly with the hydracids, but with the
oxygen acids the combination is effected by the appropriation
of the elements of one atom of water, analogous to the other
organic bases and ammonia. I have in vain endeavoured to
extend this analogy with ammonia by the formation of com-
pounds similar in constitution to amide and ammonium.
Cyanol is not acted upon by oxalate of the oxide of ethyle ;
potassium amalgam decomposes the neutral salts of this base,
with the elimination of hydrogen gas and the separation of
cyanol.

Sulphate of Cyanol. — I obtained this salt by treating an aethe-
real solution of the crude oil with some drops of concentrated
sulphuric acid. The whole liquid became a white crystalline
mass. By washing with absolute alcohol all the leucol is re-
moved. I dissolved the washed crystalline mass in boiling
absolute alcohol, which separated the last trace of ammonia.
This salt is insoluble in aether, difficultly soluble in absolute
alcohol, but easier in dilute; in water, particularly when boil-
ing, it is copiously dissolved. The boiling saturated solution
solidifies on cooling. The sulphate crystallizes, when allowed
to evaporate spontaneously, in a crust upon the vessel ; the
crystalline form cannot be accurately determined. The solu-
tion is acid, and becomes quickly red when exposed to the air ;
a stream of hydrosulphuric acid destroys this colour, depositing
sulphur.

This salt can be dried on a water-bath without decomposi-
tion. It assumes a light fawn colour. At a higher tempera-

contained in Coal-gas Naphtha* 1 95

ture it is decomposed, eliminating first cyanol in vapour, then
sulphurous acid; a bulky, difficultly combustible charcoal re-
maining behind.

I have determined the quantity of sulphuric acid only in
this salt, because the sulphate of benzidam had been previ-
ously analysed by Zinin.

Analysis: 0*994 grm. of sulphate of cyanol, dried at 212°
and precipitated by chloride of barium, gave 0*832 grm. of
sulphate of barytes.

This, when represented centesimalJy, gives 28*672 sulphuric
acid; Zinin found 28*99; the formula S03+C,2 H7 N + HO
corresponds with 28*024 per cent, of sulphuric acid.

Oxalate of Cyanol. — This salt is easily prepared by adding
oxalic acid to a spirituous solution of cyanol. The crystalline
mass, washed and dissolved in a very small quantity of boil-
ing water, separates on cooling in shining, stellate, oblique
rhombic prisms. These crystals are insoluble in aether, spa-
ringly soluble in absolute alcohol, but copiously in water.
The solution reddens litmus, and when exposed to the air be-
comes quickly coloured, depositing a brownish-red powder.
The oxalate of cyanol cannot be dried at 212°, because at
this temperature it becomes yellow and evolves cyanol. When
dried for eight days in the water-bath, the weight did not re-
main constant, and the analyses which I performed at different
periods gave me such different results that I could not reduce
them to simple proportions. I therefore burnt the salt dried
in the air and obtained the following results: —

0*5956 gvm. of oxalate of cyanol gave 1*3266 grm. of car-
bonic acid and 0*324 of water.

These numbers, stated centesimal ly, agree with Fritzsche's
analysis of the oxalate of aniline.

Cyanol salt. Aniline salt.

Carbon . . . 61*251 61*33

Hydrogen . . 6*044 5*77

From the above is deduced the formula C2 Os + C12 H7 N
+ HO, which gives 61*074 per cent, carbon and 5*741 water.

Nitrate of Cyanol. — When a mixture of dilute nitric acid
and cyanol is allowed to stand for some time, this salt is de-
posited in compact concentric needles, which can be obtained
pure and dry by pressing them between folds of bibulous
paper. The mother liquor is of a red colour; and the sides
of the basin containing it present a blue efflorescence, so that
the whole might be mistaken for solution of cobalt. The cry-
stals, when cautiously heated, melt, and evaporate into a co-
lourless vapour, which condenses in flowery crystals upon the
sides of the vessel. A small portion of the nitrate of cyanol is

02

196 Dr. A. W. Hofman on the Organic Bases

decomposed in melting, and hyponitrous acid fumes areevolved.
When this salt is heated quickly upon platinum-foil, cyanol
escapes, leaving behind carbon.

When ordinary concentrated nitric acid is mixed with
cyanol, the whole liquid solidifies into a rose-red crystalline
paste. If the acid is highly concentrated, or if a great eleva-
tion of temperature ensues, the liquid suddenly changes to a
dark colour, owing to a transformation taking place, to which
I shall advert hereafter.

Hydrochlorate of Cyanol is procured as a crystalline mass
by the direct combination of anhydrous cyanol and hydro-
chloric acid. By re-crystallization from water or spirits of
wine, in both of which it is soluble, it is obtained in fine
needles, possessing an astringent taste. I could not obtain
this salt in crystals from the strong smelling base, for when I
mixed it with hydrochloric acid the whole became a viscous
syrup. When the smelling cyanol is dissolved in sether (in
which the hydrochlorate is insoluble), and a stream of dry
hydrochloric acid gas is passed through the solution, the hy-
drochlorate of cyanol falls in the form of a heavy glutinous
liquid, but no crystals appear. The salt is not altered by
sublimation. I thought a third analysis of this compound un-
necessary, as Fritzsche has investigated the hydrochlorate of
aniline, and Zinin the benzidam salt. The analyses of the
above chemists agree with the formula CI H + C12 H7 N.

Chloride of Platinum and Cyanol. — I have already mentioned
this salt when treating of the determination of the atomic
weight of the base. It is obtained as an orange-yellow coloured
crystalline mass, when cyanol, hydrochloric acid, and chloride
of platinum are mixed together. The acid must be used in
excess, because if the base predominates the solution becomes
brown from the occurrence of decomposition. When hydro-
chloric acid and cyanol are heated with an equal volume of
alcohol before the addition of chloride of platinum, the salt
takes a longer time to separate; but when produced, is in
more beautiful acicular crystals. These crystals were washed
with a mixture of alcohol and aether, in which they are only
sparingly soluble, and dried at 212° Fahr.

By igniting with chromate of lead 1*0575 grm. of chloride
of platinum and cyanol gave 0*9288 grm. of carbonic acid and
0*2545 grm. of water.

The chlorine was ascertained by treating the salt with
caustic lime, dissolving the residue in nitric acid, and precipi-
tating with nitrate of silver.

I obtained from 1*1825 grm. of chloride of platinum and
cyanol 1*669 grm. of chloride of silver.

Theory.

Found.

24*282

24-153

2*666

2-674

4-722

35-4-25

34-816

32-905

32-890,32-883

100-000

contained in Coal-gas Naphtha. 197

I have already alluded to the determination of platinum.
This analysis leads to the formula adopted at the determina-
tion of the atomic weight, CI H, C12 H7N + Cl2Pt, which is spe-
cified in the following calculated per cents.: —

1 2 atoms Carbon . . 91025

8 ... Hydrogen . 99'83

1 ... Nitrogen . 177*04

3 ... Chlorine . 1327*95

1 ... Platinum . 1233*50

3748*57

Chloride of Mercury and Ci/anol. — I have already adverted
to the white precipitate produced by cyanol in chloride of
mercury. If in this experiment cyanol alone or a watery so-
lution of it be employed, the double compound ascends to the
surface of the liquid in the form of a pasty mass. When cor-
rosive sublimate is mixed with an alcoholic solution of cyanol,
a silky white powder is formed, which, after some time, be-
comes crystalline. By washing with water, in which it is only
slightly soluble, the crystals are obtained pure. This salt does
not change its colour at 212°, but cyanol is slowly separated,
for which reason I analysed the compound dried at the ordi-
nary temperature of the air.

The carbon and chlorine were determined in the usual way.
I endeavoured to combine the determination of the mercury
with the chlorine, by forming a bulb of about three inches in
length in the foremost part of the combustion tube, in order
to receive the mercury. In this procedure, however, it is very
difficult to separate the mercury from the undecomposed
cyanol, which distils over during the operation. The analysis
succeeds, however, very well when the salt is ignited with
chromate of lead, if the forepart of the tube is cut off with a
file after all the mercury has collected in the appropriated
bulb, and the water, which has passed over, removed by suck-
ing a stream of cold air through the apparatus. The forma-
tion of a small quantity of hyponitrite of mercury causes some-
times a slight excess in the result.

I obtained in my analysis the following numbers : —

0*7153 grm. of chloride of mercury and cyanol gave 0'3693
grm. of carbonic acid ; 2*6675 grm. of chloride of mercury
and cyanol gave 2*2005 grm. of chloride of silver; and 1*1603
grm. of chloride of mercury and cyanol gave 0'7035 grm. of
mercury.

From the above is deduced the formula Cl2H7N + 3(C1 Hg),
which I annex in per cents.

198 Dr. A. W. Hofman on the Organic Bases

Composition in per cents.

Theory.

Found.

] 2 atoms Carbon .

910-250

14-448

14-197

7 ... Hydrogen

87-357

1-387

1 ... Nitrogen .

177*040

2-811

3 ... Chlorine .

1327*950

21-078

20-356

3 ... Mercury .

3797460

60-276

60-630

6300-057 100-000

This compound is distinguished, in reference to its consti-
tution, from the double salt of platinum; as the cyanol is in
this instance in direct combination with the chloride of mer-
cury, thus resembling the corresponding salt of nicotine, inves-
tigated by Ortigosa*, and the chloride of thiosinnamine and
mercury, analysed by Varrentrapp and Will f.

The chloride of mercury and cyanol is sparingly soluble in
boiling alcohol, and is deposited again in crystals upon cool-
ing. It is also dissolved by hydrochloric acid; but when too
little of this acid is added, the undissolved portion on being
heated melts to a red oil, which covers the bottom of the tube ;
upon the addition of more acid the liquid clarifies, and depo-
sits gradually beautiful white crystals. I am not certain if this
is the unchanged mercury salt, or whether hydrochloric acid
enters into its composition.

The mercurial compound is partially decomposed by boil-
ing water ; vapours of cyanol are liberated, and a canary-yellow
powder subsides, which is similar to that which Kane obtained
when boiling the chloro-amidide of mercury J. On cooling,
the chloride of mercury and cyanol separates from the liquid,
apparently unchanged.

I have not examined the other salts of cyanol ; I shall there-
fore only remark that the phosphate is obtained as a crystal-
line mass, by bringing together anhydrous cyanol and ordinary
phosphoric acid. It is very soluble in water and alcohol. A
mixture of tartaric acid and cyanol solidifies in a similar
manner. From a hot watery solution the tartrate shoots into
long needles.

The sulphite crystallizes when a watch-glass, moistened
with cyanol, is held over a flask from which sulphurous acid
is escaping.

When an excess of an alcoholic solution of carbazotic acid

* Liebig's Ann. B. xli. p. 114.

•j- Liebig's Ausg. v. Geiger's Handb, p. 1172.

J When chloro-amidide of mercury (HgCl + Hg N H2) is boiled in water,
it is converted into a heavy yellow powder, which Kane has shown to he
composed of the double chloride and amide of mercury, with oxide of
mercury (Hg C1 + Hg N H2 + 2 Hg O) . .

contained in Coal-gas Naphtha. 199

is added to cyanol, there is produced a lemon-yellow precipi-
tate of carbazotate of cyanol. This salt is soluble in boiling
alcohol, and crystallizes from the solution upon cooling. Con-
centrated acetic, hydrocyanic and hydrofluosilic acids, when
mixed with the anhydrous base, produce no crystals.

The property which cyanol possesses of forming double
compounds with the chlorides of several metals, is very re-
markable ; besides those already mentioned it unites with the
protochloride of tin and chloride of antimony. These salts
are produced when the precipitates, which cyanol forms in
their chlorides, are dissolved in hot diluted hydrochloric acid.
Upon cooling, well-formed crystals are obtained, especially of
the tin compound.

The double compounds of the oxygen salts are procured
with greater difficulty. By mixing sulphate of copper with
cyanol, a double salt, which is very prone to decomposition,
is deposited, but I could not obtain it in well-formed crystals.
Sulphate of copper or nickel, although forming double salts
with sulphate of ammonia, always crystallized separately from
their solutions when mixed with sulphate of cyanol.

I tried to obtain alums by replacing the alkaline base with
cyanol, but with no greater success. A mixture of sulphate
of alumina and sulphate of cyanol concreted after some time
into a confused crystalline mass, in which I could not discern
any octahedrons. Further, when sulphate of the peroxide of
iron was added to sulphate of cyanol the liquid assumed a dark
red colour, owing to the oxidation of the latter base, and sul-
phate of the protoxide of iron crystallized from the solution.

Products of the Decomposition of Cyanol.

Cyanol is remarkable for the great variety of decomposi-
tions which it undergoes with other bodies. I have already
noticed the blue precipitate which it gives with an aqueous so-
lution of chromic acid. If anhydrous cyanol is mixed with
dry chromic acid, ignition immediately ensues, the mixture
burns with a brilliant flame, emitting an agreeable odour, and
oxide of chromium remains. All other bodies which impart
oxygen produce with cyanol blue substances similar to that
with chromic acid, and this decomposition occurs with so much
facility, that my vessels when exposed to the air of the labora-
tory sometimes became covered with a bluish-green coating.

Action of the Oxygen Compounds of Chlorine upon Cyanol. —

I was engaged in studying the nature of these changes when

Fritzsche* published some researches which he had performed

in a similar direction with aniline. He obtained by the action

* Bullet. Sclent, de St. Peter sb. t. i. p. 103.

200 Dr. A. W. Hofman on the Organic Bases

of the oxygen compounds of chlorine upon that substance the
coloured product of oxidation in the form of violet blue flakes,
which, when washed with alcohol, assumed a green hue.
Fritzsche expresses its composition by the formula C24 H10
N2C10. (?)

By the prolonged action of chlorous acid upon the liquid
from which the blue deposit had been separated, he obtained
the yellow crystalline substance which Erdmann discovered
when acting upon chlorisatine and bichlorisatine with chlorine,
and which he called chloranil.

I repeated these experiments with cyanol, and, as might be
expected, obtained the same results.

Fritzsche employed for the production of the blue compound
a mixture of hydrochloric acid and chlorate of potash, to
which was added an alcoholic solution of a salt of aniline.
Some hours afterwards the mixture was filled with the blue
flakes. This method is defective, at least I had to perform a
number of experiments before I arrived at the proper propor-
tions. When a solution of cyanol in hydrochloric acid is
treated with a few drops of free chlorous acid, prepared ac-
cording to Millon's method, the whole liquid immediately
coagulates into a blue mass. This body, after being well
washed, is decomposed in presence of potash and ammonia,
and chlorine is liberated.

As Fritzsche is engaged with this subject I have not pursued
it further.

I have procured chloranil* both from cyanol and benzidam,
possessing all the properties which Erdmann attributed to it.

When to an alcoholic solution of these bases concentrated
hydrochloric acid is added, and into the mixture, while boil-
ing, small crystals of chlorate of potash are projected, chlo-
ranil is obtained perfectly pure in gold-yellow crystalline scales
without the liquid becoming blue. In this process the alcohol
should not be employed in too large a quantity, or much
chlorate of potash will be wasted, and large quantities of acetic
aether disengaged.

When the composition of cyanol (C12H7N) is compared
with that of chloranil (C6C1202), the formation of this body
is readily comprehended. All the carbon is found again in
the chloranil; one part of the hydrogen is replaced by chlo-
rine; another escapes with nitrogen in the form of ammonia.
Indeed, when lime is added to the mother liquor of chloranil,
ammonia is perceptible in very large quantities.

Action of Chlorine upon Cyanol. — When chlorine gasistrans-

* It can also be obtained from phenile, salicine and several other bodies,
as will be shown in a future paper.

contained in Coal-gas Naphtha. 201

milted through anhydrous cyanol, it becomes immediately
black, with evolution of heat and formation of hydrochloric
acid. After some moments it is converted into a tenacious
resin, which obstructs the mouth of the gas tube. To prevent
this taking place, the oil must be dissolved in either water, al-
cohol, or hydrochloric acid, and the chlorine then passed into
the solution. When the gas had permeated the liquid for some
hours, I removed the apparatus and allowed it to cool. The
black mass collected at the bottom of the vessel in the form of
a friable resin ; and the clear supernatant liquor exhibited
glittering crystals floating through it.

I levigated the resinous matter with water, and then poured
it into a retort and distilled ; there passed over with the watery
vapour, a body which concreted into white laminae and floated
on the surface of the distillate in the receiver.

These crystals possess a peculiar odour, and are soluble in
cold alcohol and boiling water. The solution has not an acid
reaction. When moderately heated with potash in a retort
they again distilled over unchanged.

I did not obtain this body in a sufficient quantity to make a
burning, but it is probably the same product which Erdmann*
obtained when distilling chlorindopten with alkalies, and which
he named chlorindatmite. The same substance appears to be
formed when cyanol is distilled with peroxide of manganese
and hydrochloric acid, for it possesses all the above-mentioned
properties.

When, in the distillation of the tarry mass obtained by the
action of chlorine on cyanol, the water and volatile solid pro-
ducts have passed over, the residue liquefies, and, as the tem-
perature rises, gives off hydrochloric acid, and a yellow nau-
seous oil distils over in small globules, which solidify into a
crystalline mass in the neck of the retort, and there remains
behind a porous charcoal.

The odour perceived in this operation strongly reminded
me of chlorophenissic acid, which I had prepared a short time
before from the hydrate of phenyle. I therefore treated the
crystals with potash, and found that the odour disappeared,
but a small portion of the resinous matter, which had mecha-
nically distilled over, remained undissolved. I added hydro-
chloric acid to the solution, when a white flocculent precipi-
tate appeared, which is nothing less than Erdmann's chlorin-
doptic acid (chlorophenissic acid of Laurent). I washed it,
to separate all the hydrochloric acid, suspended it in water, and
added ammonia cautiously until the whole was dissolved.

Nitrate of silver produced in this solution a voluminous
* Erdmann's Journ. B. xix. p. 321.

202 Dr. A. W. Hofman on the Organic Bases

to1

cw

H9

NOs

ci6

Vw

', H3

o9

.a

H,

Clg

Ha

N

lemon-yellow precipitate, which is characteristic of chlorin-
doptic acid ; sulphate of copper gave a purple violet deposit,
partially soluble in alcohol. The salts of lead and chloride of
mercury produced white precipitates. The formation of chlo-
rindoptic acid from cyanol is not surprising, as the two bodies
contain an equal number of equivalents of carbon ; the hydro-
gen is partly replaced by chlorine and partly given off with
the nitrogen as ammonia.

One atom of cyanol, two atoms of water, and six atoms of
chlorine contain the elements of one atom of ammonia, three
atoms of hydrochloric and one atom of chlorindoptic acid.

1 atom of Cyanol C12 H7 N

+ 2 atoms of Water .... H2 G2

+ 6 ... Chlorine .... Cle

C12H9N02C
1 ... Chlorindoptic acid .
+ 3 ... Hydrochloric acid .
+ 1 ... Ammonia . . .

'C12H9N02C16
If anhydrous cyanol be heated with strong hydrochloric
acid, and a considerable quantity of chlorate of potash added
to the boiling mixture, a violent reaction ensues, whereby
chloranil, contaminated with a red resinous substance, is ob-
tained. This matter may be separated from the chloranil by
boiling in alcohol. When the alcoholic solution is subjected
to distillation, and till the spirit has passed over, a small por-
tion of chloranil sublimes out of the melting mass. Hydro-
chloric acid is then evolved, and in the neck of the retort a
crystalline substance condenses, which presents the odour and
all the characteristics of chlorindoptic acid.

This body is Erdmann's* chlorated chlorindoptic acid
(chlorophenussic acid of Laurent). Erdmann obtained it also
as a secondary product in the preparation of chloranil.

Its formation is perfectly explicable, since its constitution
differs from that of chlorindoptic acid, by two more atoms of
its hydrogen being replaced by chlorine.

Action of Bromine upon Cyanol. — I have not yet been able to
prepare the bromindoptic acid (Laurent's bromophenissic
acid). The action of bromine upon cyanol is very different
from that of chlorine. When bromine water is added to a
hydrochloric solution of cyanol, a white precipitate with a
slight tinge of blue falls, which quickly assumes a crystalline
aspect. None of the other oily bases present a similar reac-
tion. This compound is not however bromindoptic acid, but
* Erdmann's Journ. B. xxii. p. 257.

contained in Coal-gas Naphtha, 203

the substance which Fritzsche* discovered and named bro-
maniloid. Its composition is C12(H4Br3)N, that is cyanol,
in which three equivalents of hydrogen are replaced by a cor-
responding number of equivalents of bromine.

This body is also procured by boiling cyanol with an excess
of bromine water; it falls to the bottom of the vessel as a dark
oily stratum. When cold, and the solution of hydrobromic
acid poured off, the solidified mass is washed with water and
then dissolved in boiling alcohol. During the filtration of
the liquid the salt is generally deposited in the tube of the
funnel in silky radiated crystals. In the same state it covers
the sides of the vessels in which it is sublimed.

Action of Iodine upon Cyanol. — Iodine dissolves copiously in
cyanol, and in a short time there separates from the brown so-
lution, white, perfectly formed, elongated tables of hydriodate of
cyanol, which may be obtained pure by pressing them between
folds of bibulous paper, and washing with aether. Fritzsche +
has observed a similar decomposition with aniline. The mother
liquor contains another iodine compound which I have not
further examined.

Action of Nitric Acid upon Cyanol. — I have already adverted
to the fact of cyanol mixing with dilute nitric acid without de-
composition ; however, if the anhydrous base be treated with
a few drops of fuming nitric acid, the liquid becomes of a beau-
tiful deep blue colour, resembling the ammoniuret of copper.
At a moderate temperature this blue colour is converted into
a yellow, accompanied by an extraordinary evolution of heat,
which sometimes amounts to an explosion. The liquid passes
through every shade of colour to the deepest scarlet, and upon
cooling is filled with a quantity of red tabular crystals, which
I rinsed with water. They had a bitter taste, and dissolved
with difficulty in boiling water. Potash produced immediately
in the solution an intense yellow colour, which permanently
tinged the skin ; and the liquor, upon cooling, deposited long,
yellow, iridescent shining prisms of carbazotate of potash.

We might have anticipated the conversion of cyanol into
this acid. The whole of the carbon of the base remains in
the carbazotic acid ; 1 equivalent of cyanol and 6 equivalents
of nitric acid contain the elements of 1 equivalent of carba-
zotic acid, 4 equivalents of hyponitrous acid, and 4 equivalents
of water.

1 equiv. Cyanol C12H7N

+ 6 ... Nitric acid .... NgO^

C12 H7 N7 O30

* Bullet. Scicnt. de St. Pitersb. 1843, t. i. p. 30. f Ibid. p. 103.

201 Dr. A. W. Hofman on the Organic Bases

*->'

1 equiv. Carbazotic acid . . C12H3N3014
f4 ... Hyponitrous acid . . ^4^)12

+ 4- ... Water H4 Q4

It is well known that Laurent obtained by the action of
nitric acid upon the hydrate of phenyle, besides carbazotic
acid, another nitrogen compound, the nitrophenessic acid,
which is formed when ordinary nitric acid is employed. Cya-
nol likewise contains all the necessary conditions for the for-
mation of this acid, but as yet I have not been able to prepare
it. Nitrophenessic acid is readily distinguished from carba-
zotic acid by forming a very characteristic salt with ammonia.

I have yet to notice the decomposition which cyanol under-
goes by oxidation with hypermanganate of potash and per-
oxides of lead or manganese. These decompositions, how-
ever, present nothing remarkable. A solution of hyperman-
ganate of potash on the addition of cyanol coagulates into a
pasty mass, from the separation of hydrated peroxide of man-
ganese. The filtrate contained oxalic acid and the nitrogen
of the base in the form of ammonia.

If a solution of cyanol in sulphuric acid be boiled with per-
oxide of lead, carbonic acid is expelled, and the blue liquid
acquires the odour of formic acid. Hydrate of lime evolves
a large quantity of ammonia when added to the limpid liquid.

Action of Potassium upon Cyanol. — This metal decomposes
cyanol in so remarkable a manner that I cannot at present ex-
plain it. The potassium is dissolved, disengaging hydrogen;
the whole liquid thickens into a violet-coloured paste, and on
its surface float red coloured drops of undecomposed oil. The
violet colour soon becomes dirty brown, but we have no evi-
dence of the formation of cyanide of potassium.

When potassium is melted in an atmosphere of the vapour
of cyanol, the latter is rapidly decomposed, depositing carbon.
By treating the black residue with acids, it gives off' large
quantities of hydrocyanic acid, for if a mixture of a protoxide
and peroxide salt of iron are added to the solution, a precipi-
tate is obtained, which affords, when treated with hydrochloric
acid, pure Prussian-blue.

The facts which I have now passed in review appear to me to
prove satisfactorily the identity of cyanol, benzidam, and the base
obtained by the dry distillation of indigo and anthranilic acid.

It is very interesting thus to arrive at the same substance
when pursuing paths of investigation so different. Many other
organic bodies, which, when first discovered, could be ob-
tained only by one process, have afterwards been found to

contained in Cool-gas Naphtha. 205

emerge from the decomposition of numerous and most various
compounds.

In like manner cyanol will most probably be found in the
products obtained by submitting a still greater number of or-
ganic substances to destructive changes.

I have not at present recognized cyanol in animal tar oil
{Oleum animate, Dippelii), in which Unverdorben discovered
a series of bases, of which little is known.

The simultaneous occurrence of cyanol and carbolic acid
in the products of the distillation of coal, and the production
of chlorophenissic, chlorophenussic, and carbazotic acids from
these bodies, led me to institute a comparison between them.
Their mutual relations are manifested in the two following
formulas. U, with Laurent, we regard carbolic acid as the
hydrate of an oxygen compound of an organic radical C12 H5,
cyanol may be considered as an amide compound of the same
radical, and we thus obtain the following series: —
Hypothetic radical . . . . C12 H5 Phen.

Carbolic acid C„H- 0 + HO|HydT ?,the

u ° I. oxide of phen.

Chlorindoptic acid . . . . cJ^f O + HO/CMorophenissic
Chlorated chlorindoptic acid. Cu Cl5, O + HO { Chjorophenussic

*iiiiii c12{^04)> 0+Ho{Nirnissic

Cyanol C12H5 +NH2 Phenamide.

I have attempted to produce cyanol from carbolic acid, but
without success. This acid absorbs ammonia with great
avidity, but no decomposition takes place. I was not more
fortunate in my attempts to procure carbolic aether. I thought
there was a possibility of preparing phenamide in a manner
similar to that in which oxamide and fumarimide are formed,
from the corresponding ethyle compounds by means of am-
monia.

In conclusion, I shall make a few remarks upon the names
of this base, there being a choice of four. The name cyanol
should on all accounts be discarded, not only because it is
formed from two languages (xvuveog and oleum), but also on
account of the accentuated Greek adjective being already em-
ployed in chemistry to designate another body. The terms
aniline and benzidam have reference to the relation of the base
to certain classes of combinations. But since it is formed, as
we now know, in different ways, it is perhaps better to retain
the old name crystalline, derived from a very characteristic
property of this body, until experiments place the scientific
name, phenamide, on a firmer foundation.
[To be continued.]

[ 206 ]
XXXV. Proceedings of Learned Societies.

ROYAL SOCIETY.

[Continued from vol. xxiii. p. 385.]
Nov. 23, rr,HE following papers were read, viz. —

1843. -* 1. "Magnetic Term Observations at Prague, for
May, June, July and August, 1843." By Professor Kreil. Com-
municated by S. Hunter Christie, Sec. R.S., &c.

2. " Variations de la Declinaison et Intensite Magnetique obser-
vers a Milan le 26 et 27 Mai, le 21 et 22 Juin, le 19 et 20 Juillet,
le 25 et 26 Aout,le 20 et 21 Septembre,le 18 et 19 Octobre, 1843."
By Sig. F. Carlini, For. Mem. R.S.

3. " An Account of a remarkably large and luminous Spot in the
Sea." By Captain F. Eardley Wilmot, F.R.S. With remarks on
the water taken thence : in a letter to S. H. Christie, Sec. R.S.,
from Lieut. Manley Dixon, R.A.

The letter is as follows : —

Dear Sir, Woolwich, October 6th, 1843.

Captain F. Eardley Wilmot, on his voyage home from the Cape of
Good Hope in the spring of this year, observed one night a remark-
able, though not very uncommon appearance of the sea. This was
a large and very luminous spot, which was clearly defined by a
sharp edge. He thus describes the appearance, and also the steps
which he took to obtain some of the water for the purpose of
bringing it home to England and submitting it to a chemical test.

" The sea was covered with so brilliant a surface of silver light
that we could see to read, and the shadows of ropes, &c. were
strongly marked. We sailed through it for about four hours. In
one place it had an edge ; and we sailed out of it for nearly half an
hour, when we again entered it as abruptly, and finally left it, when
the edge of the illuminated part was strongly defined. The water
was taken up in a clean bucket and put into a carefully cleaned
bottle ; about 10° north latitude."

As Captain Wilmot's time in England was limited, he left the
bottle of sea water with me, and I took the first opportunity of show-
ing it to Dr. Faraday, who took it to London with him, and wrote
me a note, of which the following is a copy.

" Royal Institution, September 25th, 1843.

" Dear Sir, — I have examined the water, and it is peculiar in
some points. It contained much sulphuretted hydrogen, and also a
portion of solid deposit, which was about one half sulphur and the
other half organic matter. There has no doubt been considerable
change in the contents of the water, and I cannot now recognise
organic forms ; but the presence of the animal matter, the sulphur,
and the sulphuretted hydrogen, all agree with the idea that the water,
when taken up, was rich in animals or animalculse.

" I am, Sir, yours very truly,
" Lieut.Dixon,B.N.,&c\&c." " M.Faraday."

I remain, Sir, yours very truly,
Professor Christie, W. Manley Dixon.

Royal Military Academy, Woolwich.

Royal Society : Anniversary Proceedings, 1843. 207

November 30. — Anniversary Meeting. — The President addressed
the meeting as follows : —

Gentlemen,
In addressing you on the present recurrence of our Anniversary, I
have to make the same acknowledgment to the Council which has
assisted me during the past year, that 1 have had to make to their
predecessors. If your affairs have proceeded prosperously, it has
been mainly owing to their unremitted exertions. Since our last
Anniversary, there are not many events to which it will be my duty
to refer. The first that I shall bring under your notice is one of
the most gratifying description — the return of Captain James Clark
Ross, and the vessels under his orders, from the Antarctic regions of
the globe. This expedition, undertaken by the Government in a
great degree on the recommendation of the Royal Society, has re-
turned after almost entire success. 1 trust that the account of this
most interesting voyage will be given to the public by its gallant
commander, who has approached to both limits of the world. A
portion of its valuable scientific details has been already given to
our Society ; and the magnetic observations made by Captain Ross
and his officers, with so much assiduity and ability, will be the
enduring monument of their fame, as long as industry and science
are held in honour by mankind*. The magnetic maps of the South
Polar regions will be a result which all philosophers must hail with
delight, while the geographer will rejoice in the advancement of our
knowledge so far to the southward of all former navigation, and in
our acquaintance with a new polar volcano, compared to which
Hecla sinks into insignificance f.

It is a great addition to our pleasure on this occasion, that so few
casualties have happened during the three years' absence of Captain
Ross and Captain Crozier from England, and that no officer or sailor
has been a victim to disease, except one seaman who died on the
homeward passage. This, when we reflect on the length of time to
which the expedition extended, and the severity of the climate that
it had to face, is no small tribute to the care of the commander of the
two vessels employed, and the skill of the surgeon, to whom the
health of those on board was committed. When we advert to the
dangers that the vessels were exposed to, from the icy barriers of these
new-found regions of the earth, we cannot be sufficiently grateful
to Divine Providence for having preserved lives so valuable to their
country, and so dear to every lover of science.

During the last year the Society has lost few of its members.
Only one of its foreign ornaments has it lost, M. Bouvard, a distin-
guished astronomer. The number of those who contribute to our
Transactions is not at all lessened. We have, however, to lament
the death of an illustrious Prince, who for several years presided
over our body, and whose regard for us remained undiminished to
the last. On this occasion we felt it our duty to lay before the
throne the expression of our respectful condolence with our Royal
Patroness, on the death of her illustrious uncle ; and we also sus-
* See Phil. Mag. S. 3. vol. xxiii. p. 380. f Ibid. vol. xx. p. 141.

208 Royal Society : Sir J. F. W. Herschel on Prof. Forbes' s

pended our Meetings, to mark our sense of the loss that we, as
well as the public, had sustained.

The Council, in pursuance of its duty, has awarded the Royal
Medals to Professor Forbes of Edinburgh and Professor Wheat-
stone of King's College, and the Copley Medal to Professor Dumas.
I regret extremely that I cannot bestow the latter on our illustrious
colleague in person. His presence to-day would be truly gratifying
to us all. I still more regret the absence of Mr. Forbes, as it is
owing to ill health that he is still on the continent. I must there-
fore request Mr. Christie to transmit the Medal to his friend.
Mr. Christie,

In the absence of Professor Forbes, I must request you to receive
for him this Medal, which is the second that has been given to him
by the Royal Society. In awarding it to his researches on the law
of extinction of the solar rays*, the Council have not alone been
guided by their own sense of the author's merits, but also by a de-
tailed report with which Sir John Herschel has favoured them f. As

[* An abstract of these researches will be found in Phil. Mag. S. 3. vol.
xxi. p. 223.]

f Sir John Herschel's report, above referred to, is as follows : — " Mr.
Forbes's paper, as far as my knowledge extends, records the first at-
tempt, and that in no slight degree successful and satisfactory (consider-
ing the very great complexity of the physical considerations it involves
and the difficulty of the experiments themselves), to obtain a positive
measure of the extinction of solar heat (as distinguished from light), in
traversing a measured portion of the atmosphere, and that one, of which
the meteorological conditions have been carefully ascertained at the two
extremes, and therefore in which the nature and density of the medium
traversed within their limits have been determined by direct observation as
well as such data can be ascertained at all on the great scale. For this
purpose, simultaneous observations are indispensable ; and in the choice of
a coadjutor, Mr. Forbes must be allowed to have been highly fortunate.
The rarity of opportunities for such observations to be made with any
prospect of a dependable result, I am satisfied, from my own experience,
is by no means overstated by Mr. Forbes. That of which he availed
himself seems to have been as nearly unexceptionable as could have oc-
curred, and to have been used with all regard to the obtaining a precise
knowledge of the meteorological particulars capable of influencing the
result. In such cases a single series under unexceptionable circumstances
thoroughly worked out may and must afford results far more valuable than
any number of series obtained on less select occasions.

"The mode in which Mr. Forbes has analysed his own and M. Kamtz's
observations on the Faulhorn and at Brientz, as well as the conclusions
he deduces from them, are both in many respects remarkable. The method
of graphical interpolation is resorted to throughout, and curves so deduced
expressing at once to the eye and to the reason the simultaneous variations
of all the meteorological elements at both stations, as well as the march
of the actinometer. The comparison of these last curves leaves no room
to doubt either the practical efficiency of the method of observation pur-
sued, or the nature of the causes in action which give rise to the many
remarkable and corresponding peculiarities which their forms exhibit, and
which, as general affections of the actinometric curve, Mr. Forbes has
examined and traced up to their origin in the combination of the sun's

Paper on the Law of Extinction of the Solar Rays. 209

this report will be printed I shall refer you to it, feeling that I could
not, by anything that I might say, add to its effect on your minds.
I must, however, be allowed to congratulate Mr. Forbes on these

varying altitude, and the hygrometric changes induced on the column of air
traversed by his rays, by the heat already developed. It is a curious and
complex case of causation in which the direct and immediate effect of the
cause is modified by an indirect one of a cumulative kind, resulting from the
totality of its action from its commencement to the time of observation .

" The comparison of the hygrometric curves with the actinometric leads
to no very distinct conclusion, though this is a point on which Mr. Forbes
has bestowed great attention. A general but not very precise analogy is
pointed out between the curve of mean dampness and that of relative
extinction ; but on the whole, no distinct relation is pointed out between
that dampness which affects the hygrometer and that which disturbs the
merely aerial extinction of solar heat — (if indeed simple dampness, as such,
be the only or the principal disturbing cause).

" On the hypothesis of ' uniform opacity,' or that in which the extinction
varies in geometrical progression as the mass of air traversed varies in
arithmetical, Mr. Forbes, calculating on the whole series of observations
in question, concludes an extinction of 31£ per cent, of the incident heat-
ing rays in passing vertically through the atmosphere under the conditions
of mean barometric pressure, and a dampness such as prevailed on the
average during the day of observation, thus appearing to afford a con-
firmation at once interesting and unexpected of the results of Bouguer and
Lambert, as deduced on a similar hypothesis, from their experiments on
the extinction of light, though properly speaking it is impossible to argue
from one case to the other.

" But Mr. Forbes adduces a great many considerations, both theoretical
and practical, in proof that such a law of extinction cannot be that of
nature — the incident heat being analysed in its progress, and so rendered
relatively more transmissible after passing through a certain thickness of
the medium than before it (a conclusion grounded on the discoveries of
M. De la Roche, M. Melloni, and his own) ; and secondly, laying aside every
theoretical consideration and obtaining from the series of observations
under discussion an empirical formula, by means of an interpolating curve,
expressing the rate of loss of intensity of a solar ray which has been
transmitted through a varying atmospheric thickness, in traversing the
stratum immediately subsequent, he finds for the result of this inquiry a
rate corresponding to the ordinate of a logarithmic curve, having its
asymptote not passing through the origin of the coordinates, and thence
deduces the following remarkable conclusions, which, as a result of experi-
ment and direct observation, I conceive to be of great interest, viz. —

" 1st. The extinction of solar heat in traversing vertically an atmosphere
mechanically pure and of mean barometric pressure, amounts to 0*466 of
the total incident heat at least, and may be even much greater ; so that the
absolute intensity of the solar ray, or such as it has exterior to our at-
mosphere, would appear to have been considerably under-rated.

" 2nd. The extinction of heat in a mechanically pure atmosphere has a
limit, and beyond which it might traverse any, at least a very great additional
thickness, without further loss.

" These conclusions are, however, only so far results of direct observation
as that they are concluded from it by following out an empirical curve be-
yond its observed limits. Yet when we examine the amount of deviations
the curve itself exhibits within those limits, and take into consideration
the very simple apparent law of its curvature and course, it will be allowed

Phil. Mag. S. 3. Vol. 24. No. 158. March 1844. P

210 Royal Society. Anniversary Proceedings, 1843.

researches, as one of the fruits of his arduous and meritorious la-
bours amid the eternal ice and snows of the loftiest region of Europe.
Mr. Forbes is now fairly enlisted in that enterprising scientific band
which looks up to De Saussure as its leader. His researches into
the law of extinction of the sun's rays is but a portion of the valu-
able results that he has obtained among the mountain solitudes,
where, though vegetation scarcely exists, and animal life is equally
rare, the eternal glacier itself is ever pursuing its gradual and silent
course : — silent, till it is interrogated by a philosopher endowed with
the energy and perseverance of a De Saussure in the eighteenth, or
a Forbes in the nineteenth century.
Mr. Wheatstone,
I now present you with this Medal, one of those entrusted to the
President and Council of the Royal Society by Her Most Gracious
Majesty, for your paper entitled " An account of several new Instru-
ments and Processes for determining the Constants of a Voltaic Cir-
cuit*." This is not the first time that I have had the pleasing task
of acknowledging, on the part of the Royal Society, the great inge-
nuity as well as knowledge that you bring to the increase of science.
You not only add to our store of knowledge, but you give to others
the means of doing so too. You not only set the example of
scientific pursuit, but you also facilitate it in those who may be-
come at once your followers and your rivals. In the particular case
before us, you have introduced accuracy where even rough numeri-
cal data were almost wholly wanting. The importance of such fa-
cilities in any branch of science can hardly be overrated, and I have

that the conclusions partake at least of a very high probability, amply suf-
ficient to warrant further research.

" Besides the simultaneous observations on the Faulhorn and at Brientz,
Mr. Forbes has stated in this paper the results of a great many other acti-
nometric days' work, which go to show — 1st, that the instrument really is
one which (its use being fully understood) gives highly consistent and de-
pendable results" ; 2ndly, that its indications are in a most remarkable
manner, and instantaneously affected by changes in the opacity of the at-
mosphere ; 3rdly, that in a great number of comparisons between its
indications on the summit of the Faulhorn with those simultaneously, or
nearly so, at a variety of lower stations, there occurs not one in which the
loss of heat between the stations is not a very large, distinct and easily
measurable quantity.

" Mr. Forbes says nothing in this paper of the qualities as distinct
from the quantities and chromatic properties or indices of transmissibility
of the heat stopped in the upper regions of the air. But independent of
any considerations of this nature (which however may materially affect
the relations of vegetation to altitude in mountainous districts), I am dis-
posed to regard this paper as marking a considerable epoch in that depart-
ment of meteorology which relates to the introduction and distribution of
heat among the strata of our atmosphere, and as likely to be the fore-
runner of very extensive and elaborate researches in further prosecution of
the subject."

[* For an abstract of this paper see Phil. Mag. S. 3. vol. xxiii. p. 381.]

[a For an account of the actinometer see Phil. Mag. S. 3. vol. xv. p. 307.]

M. Dumas's Researches in Organic Chemistry. 211

therefore the greatest satisfaction in being the channel of this award
of the Council of the Royal Society.
Mr. Daniell,

I have to request that you will take charge of this Copley Medal,
and transmit it to M. Jean Baptiste Dumas, for his late valuable re-
searches in Organic Chemistry, and more especially those contained
in a series of memoirs on chemical types and the doctrine of substi-
tution*, and also for his elaborate investigations of the atomic weights
of carbon, oxygen, hydrogen, nitrogen, and other elements. In be-
stowing this Medal, as awarded by the Council of the Royal Society
for scientific labours so important, I may well feel the highest grati-
fication \.

Having now performed this, the most agreeable duty of a Presi-

[* See Phil. Mag. S. 3. vol. xvi. p. 322.]

f After the classification of organic substances under compound radicals,
no feature in the recent progress of chemistry is more remarkable than the
vast additions of new compounds produced by the application of artificial
agencies to existing organic products. To this progress M. Dumas has
greatly contributed by fixing attention on the removal of one element by
another, which occurs in these reactions, and in particular to the equiva-
lent substitution of chlorine for hydrogen, which has been successfully
executed in a variety of substances by M. Dumas himself, and by others
whom his discoveries and speculations have drawn into this fruitful field
of research. The preservation of certain fundamental properties in the
new compounds thus produced, he has referred to the existence of a pecu-
liar arrangement of the constituent atoms in a compound, which arrange-
ment is supposed to be preserved on the removal of one atom, or success-
ive removal of several atoms, and their replacement by an equal number
of atoms of a different element, and is expressed by the " chemical type."

In M. Dumas's first memoir on Chemical Types, his views are illustrated
by the discovery of chloro-acetic acid, a remarkable substance, and highly
interesting in its composition, being an acetic acid (vinegar), of which the
whole hydrogen has disappeared, but is replaced by an equivalent quantity
of chlorine. In this paper, also, he first forms " marsh gas " by an arti-
ficial process, and shows its relation to the acetates. He also forms a series
of compounds by the action of chlorine upon marsh gas or " the gas of the
acetates."

The second memoir of the series makes known the action of hydrated
potass upon the alcohols, and furnishes a new and simple method of pro-
curing the acid equivalent to a given alcohol*. Thus acetic acid is alcohol,
in which two atoms of hydrogen are replaced by two atoms of oxygen, and
that acid is shown to be produced by the action of hydrate of potass upon
alcohol at a high temperature, with the evolution of hydrogen gas. To
estimate the value of these discoveries, it is necessary to bear in mind the
importance lately acquired by the bodies of which common alcohol is the
type. To discover or characterize a body as an alcohol, is to enrich organic
chemistry with a series of products analogous to those which are presented
in mineral chemistry by the discovery of a new metal. M. Dumas then
applies this new method to other alcohols, and obtains by it formic acid
from wood- spirit, ethalic acid from the ethal of spermaceti, and valerianic
acid from the oil of potatoes.

In the third memoir, M. Dumas, in conjunction with E. Peligot, de-

[• See Phil. Mag. S. 3. vol. xviii. p. 203.]
P2

212 Royal Society. Anniversary Proceedings, 184>3.

dent, I have the satisfaction to inform you, that Mr. Dollond has
been so kind as to favour us with a bust of his grandfather, John

scribes certain new compound ethers, containing carbonic acid, one of
which is remarkable for its analogy to sugar in its composition.

In addition to this series, M. Dumas, in conjunction with M. Hasfone,
one of his numerous pupils, has given to the world the results of an elabo-
rate investigation of the atomic weight of carbon, in which, independently
of the importance of the analytical result obtained, certain defects of the
method of organic analysis universally practised are first pointed out, and
a degree of exactness and precision communicated to the process which it
has never before possessed. The Council consider these researches relating
to atomic weights, which he has since extended to other elements besides
carbon, as highly interesting and as greatly enhancing the claim of M. Du-
mas, derived from his memoirs on chemical types, to the distinction of the
Society's Copley Medal. That claim he has again increased by the more
recent investigations he has undertaken of the most delicate and important
nature, in the two several departments of inorganic and organic chemistry.

The first of these embraces the analysis of air, and the composition of
water ; inquiries remarkable for the novelty and exactness of the methods
of analysis, the time and pains bestowed upon them, and the minute accu-
racy of the results. These new analyses now form the most fundamental
determinations in the science. The superior accuracy of M. Dumas's
analysis of water may be estimated from the circumstance, that while, by
the last determinations lately received, namely, those of Berzelius and of
Dulong, the proportion of oxygen to 1000 parts of hydrogen was ascer-
tained only between the limits of 7936* and 8042, the new determinations
limit the proportion of oxygen betwen 8000 and 8003. While the old
determinations also were deduced from no more than three analyses, the
new determinations are deduced from nineteen separate operations. The
exactness introduced by M. Dumas into the analysis of air is equally re-
markable, and the ultimate result is deduced from not less than one hundred
elaborate analyses of air made by that chemist and his pupils during various
seasons of the year and in different quarters of the globe*.

In the same inquiry, the object of which is to furnish chemists with
analytical constants of the highest attainable numerical accuracy, are in-
cluded new determinations of the atomic weights of several other elements
besides oxygen, hydrogen and nitrogen, the elements of air and water ;
particularly of carbon, to which reference has already been made. These
results possess peculiar interest, from confirming a theory which was pro-
mulgated many years ago by Dr. Prout, and uniformly supported since its
publication by several chemists of this country, although not assented to
abroad ; namely, that the atomic weights of all other elements are whole
numbers, or are multiples of hydrogen. This law M. Dumas has lately
extended to chlorine, silver, lead, calcium, potassium and sodium.

The new researches of the same chemist in the department of organic
chemistry have reference to the composition of the great alimentary prin-
ciples of the animal economy ; namely, albumen, fibrin, casein and gelatin,
with their origin in plants, and also the origin of the fat of animals. The
memoir which contains these inquiries is a model of chemical research,
equally remarkable for its extent, accuracy and completeness.

The recent discoveries of M. Dumas have procured for their author, in
his own country, the high distinction of President of the French Academy,
and of being the successor of Lacroix as Dean of the Faculty of Sciences
in the University of Paris.

[* See Phil. Mag. S. 3. vol. xx. p. 339-]

Obituary Notice qfH.R.H. the Duke of Sussex. 213

Dollond. This memorial of one to whose ingenuity astronomy has
been so deeply indebted, will form a valuable addition to our gallery
of illustrious men. I am also able to congratulate the Society on
the acquisition made this day of a bust of the justly celebrated
James Watt, for which we have to give our most grateful thanks to
his son. When we contemplate the features represented with so
much spirit by a Chantrey, and copied so faithfully by a Hoffernan,
we shall remember a man who by his talents conferred the greatest
benefits on the civilized world, — who endowed inanimate machinery
with the means of rapidly passing over the greatest distances by
land, and of overcoming the force of adverse winds upon the ocean,
— who brought to perfection the most important mechanical power
with which man is yet acquainted, if indeed we are ever to see it
surpassed : finally, a man who united the science of the profound
philosopher to the ingenuity of the original inventor.

I am sure that the Society will unite with me in the expression
of heartfelt sorrow that the services of Mr. Roberton have been lost
to us by his sudden and lamented death. His attention to his duties,
his zeal for the honour and interest of our Society must have been
apparent to you all, and especially to those who have formed part
of our Council ; but his merits were of course still better known to
the more permanent officers of your body, and they entirely concur
with me in this inadequate testimony of our regret.

Turning our attention to the obituary of the last year, I shall now
proceed to read it to you, premising that we have been too recently
acquainted with the death of M. Bouvard, Jun. to enable us at
present to give any account of his life and labours.

His Royal Highness Prince Augustus Frederick, Duke
of Sussex, Earl of Inverness, and Baron of Arklow, Knight of the
Garter, and Grand Master of the Order of the Bath, was born on
the 27th of January, 1773.

In early life he joined the Whig party in politics, and adhered to
it till his death. No one doubted the sincerity of his opinions ;
indeed, he must have made personal sacrifices that would forbid
the possibility of any one's doubting that they were the real con-
victions of his mind. The decided nature of his sentiments was
unaccompanied and unobscured by any shade of bitterness, and he
gave that charitable interpretation to the motives of those with
whom he differed, that he expected for his own. The eulogiums
pronounced upon him, after his death, by the Duke of Wellington
and Sir Robert Peel, are, indeed, as honourable to them as they are to
him of whom they spoke. The active part of his life, however,
was little occupied by the concerns of party ; it was rather dedi-
cated to those interests, where happily there is in this country no
party, or rather, where all are more or less of the same party. It was
in increasing the funds by which the wants of the orphan and widow
are relieved, by which the sick are» cured, and the ignorant are in-
structed, and by which comfort is given to every species of desti-
tution, that his late Royal Highness seems chiefly to have delighted.
Next to this was his interest in intellectual pursuits : he collected a

214 Royal Society. Anniversary Proceedings, 1843.

noble library, especially rich in Biblical Literature,which was the more
prized by him from his acquaintance with the Hebrew language.

He was fond of mechanics, and left at his decease a large collec-
tion of clocks and time-pieces, a taste for which he apparently
inherited from his father, George the Third. He was for many
years President of the Society for the Encouragement of Arts,
Manufactures and Commerce, a Society that has done much to
encourage mechanical ingenuity. Finally, he evinced his regard
for natural science, by presiding for several years over our Society,
in whose concerns he would probably have taken a more active
part but for the affection of his eyes, by which he was for some
years deprived partially or wholly of the blessing of sight ; a blessing,
which was, h'owever, in a great degree, restored to him by the skill
of Mr. Alexander. Those Fellows of the Society who are Free-
masons, would not be satisfied did I not allude to His Royal High-
ness's connexion with that body, of which he was during the latter
portion of his life Grand Master. In private society, the Duke of
Sussex was kind and affable, and fonder of domestic happiness than
of the state and pomp of his exalted rank. On this point, how-
ever, I shall not dilate, as the address of a President of a public
body has more to do with the public conduct than with the private
virtues of those about whom he speaks. Suffice it to say, that when
His Royal Highness departed this life, having many public and
private friends, there probably was no one who was his enemy. He
died on the 21st day of April, at the age of seventy.

Dr. John Latham was born in the year 1761. Early in life
he was appointed Physician to the Infirmary at Manchester, where
he remained three years ; and afterwards removed to Oxford, and
succeeded Dr. Austin as Physician to the County Hospital. He
finally settled in London, and obtained, in succession, the appoint-
ments of Physician to the Magdalen Hospital, the Middlesex Hos-
pital, and lastly to St. Bartholomew's Hospital. He rapidly rose to
eminence in his profession ; but the labours by which he earned
these successes had undermined his constitution ; and, at the age
of 46, his career was arrested by serious threatenings of consump-
tion, which compelled him, for a, time, to abstain from exertion and
to seek health in the retirement of the country. Contrary to all ex-
pectation he recovered, and was enabled to resume his practice in
London, which he continued for twenty years longer.

Dr. Latham did not contribute any paper to the Philosophical
Transactions ; but was the author of several memoirs on practical
subjects in the Medical Transactions of the College. In 1809, he
wrote a small volume, entitled " Facts and Opinions concerning
Diabetes." In 1814, he was chosen President of the College of
Physicians. The Medical Benevolent Society was founded by him
in 1816.

In 1829, having reached his £8th year, Dr. Latham finally left
London : he died in April last, in his 82nd year, worn out by
severe and protracted suffering.

Charles Macintosh, an eminent chemist, was born at Glasgow

Obituary Notices qfDr. J. Latham fy Mr. C. Macintosh. 215

in the year 1766. His father, George Macintosh, a native of Ross-
shire, was a merchant in that city ; and his mother was Mary
Moore, daughter of the Rev. Charles Moore, minister of Stirling.
Mr. George Macintosh first introduced the process of dyeing the
Turkey, or Adrianople red into Britain, and was much esteemed by
his fellow citizens for his charitable disposition and active benevo-
lence. Charles Macintosh's paternal uncle, William Macintosh,
obtained some notoriety about the year 1782, by the publication of
Travels in the East, in which he first propounded the greater part of
those principles of legislation which have since been adopted in the
government of our Indian Empire; and his maternal uncle was
Dr. John Moore, the well-known author of ' Zeluco ' and other
literary works of eminence, and father of the celebrated General
Sir John Moore.

Charles Macintosh received the rudiments of his education at the
Grammar-school of Glasgow, where he was distinguished for docility
of disposition and quickness of parts. From Glasgow he was re-
moved to a school at Catterick in Yorkshire ; but, being destined for
mercantile life, he was early placed in the counting-house of Mr.
Glasford at Glasgow, then one of the first merchants of the day,
where he probably acquired that accuracy in the transaction of
business details for which he was in after-life remarkable. From a
strong bent towards the pursuit of science, he also about this time,
1782, became a student in the University of Glasgow, and for
several sessions attended the chemical lectures of the celebrated
Dr. Black. It would appear that Black had remarked his assiduity
and aptitude for the study of chemistry, for he was accustomed to
detain young Macintosh after the dismissal of the evening classes,
and, walking with him to and fro in the cloisters of the old court of
the University, he examined him strictly on the subject of his pre-
vious prelections ; directing his attention to points of importance,
and explaining those of difficulty in the science as it then stood.
When Dr. Black was removed to Edinburgh, Macintosh became the
pupil of his successor Irvine, with whom he soon became as great
a favourite as he had been with Black. Whilst as yet a mere boy
he contributed to Curtis's ' Flora Londinensis ' the account of some
experiments on the culture of woad and madder, and on the mode
of dyeing with the same. He seems at this time to have been also
a botanical student of the University, and to have made many ex-
cursions in the neighbourhood of Glasgow in search of specimens ;
but it was in the branch of chemical investigation that he was
destined to become more conspicuous. The experiments which he
afterwards made in the application of incinerated Algae, as a ma-
nure, and which are related by Dr. Greville in his account of the
British Algae, come more under the head of chemical than of
botanical research. In order to perfect him in a knowledge of the
French language, the subject of this notice was afterwards removed
to the house of a Catholic clergyman in Champagne, with whom he
resided for some time, and acquired a facility in speaking and
writing French, which he retained through life.

216 Royal Society : Anniversary Proceedings^ 1843.

Before he returned to Scotland he visited Brussels, and was much
noticed by Count Lockhart, the Austrian Viceroy of the Nether-
lands. From Brussels he ascended the Rhine in company with
an English artist named Green, who was making a professional tour,
and who afterwards acquired some celebrity as a landscape painter
in water-colours, an art then in its infancy. At Weimar he made
the acquaintance of the illustrious Goethe; and, having visited
Berlin, he came to Paris shortly before the breaking out of the Re-
volution in 1789.

As Mr. Macintosh's pecuniary circumstances did not admit of his
continuing unemployed, at the time of his return to Scotland several
schemes for his future career in life appear to have attracted his at-
tention. . He was at one period upon the point of embarking as a
planter for the West Indies, and had actually entered upon ne-
gotiations with the Hudson's Bay Company to retrace the steps of
the adventurous Hearne to the shores of the polar ocean, with the
view of extending the Company's fur trade beyond the Rocky
Mountains. His love for chemistry induced him, however, to relin-
quish these schemes, and, as the result, his establishment of various
branches of chemical manufacture, including those of acetate of lead,
hitherto in Britain altogether an import from Holland ; of acetate of
alumina, so extensively employed by our calico-printers ; of alum,
before his time unknown as a manufacture in Scotland, and whereby
he converted the exhausted and deserted coal-works in the neigh-
bourhood of Campsie and Hurlet, near Glasgow, into a scene of
great and active commercial enterprise ; of Prussian blue, and of
prussiate of potash, as the mode of dyeing woollen, cotton and silk
(with which latter salt he was also the sole inventor), followed each
other in rapid succession. He was also the inventor of the process
for manufacturing the dry chloride of lime, which effected an entire
revolution in the process of bleaching, and which gave origin to the
stupendous chemical works at St. Rollox, near Glasgow, which have
since become so celebrated under the energetic management of the
Messrs. Tennants.

It had been known to chemists that naphtha, or petroleum, was
a solvent for caoutchouc, or the coagulated juice of the Iatropa
Elaslica, the Urceola Elastica, and other tropical plants. The
liquid varnish, however, thus formed, although elastic, continued
clammy and viscid when exposed to the air of the atmosphere. Mr.
Macintosh overcame this difficulty by the formation of double fabrics,
having the varnish as an adhesive waterproof film or medium in the
centre. It is unnecessary to enlarge upon the great utility of this
invention, followed as it has been by the removal of many of the
difficulties which had rendered caoutchouc a substance imprac-
ticable to manage, so as now to admit of its application to many
useful purposes in the arts. Mr. Macintosh was also the inventor
of a mode of converting iron into steel by the application of coal-gas
in hermetically closed and heated vessels ; a beautiful process, by
which much time and labour is saved.

The desire of acquiring useful information continued with Mr.

Geological Society. 217

Macintosh to be a ruling passion ; in instance of which it may be men-
tioned, that when he placed his sons as students at the University of
Glasgow in the year 1805, he again re-entered himself as a student,
and regularly attended the lectures in Natural Philosophy of the now
venerable Professor Meikleham ; and still later in life, when his friend
Dr. Thomas Thomson was appointed Professor of Chemistry at
Glasgow, in 1818, Mr. Macintosh again became a student, and
regularly attended two courses of the Professor's lectures. Latterly,
Mr. Macintosh had resided for the most part in comparative retire-
ment in the country, where he took much interest and pleasure in
planting and improving his estate of Campsie. For several years
his health had been gradually declining, and he at length expired at
his house at Dunchattan, near Glasgow, on the 25th day of July,
1843. His end, for which he was quite prepared, was characterized
by the most perfect resignation, fortitude and composure, and in
unison with the virtuous and useful life which he had led.

Mr. Macintosh married, in 1789, Miss Mary Fisher, the daughter
of Alexander Fisher, Esq., merchant in Glasgow, and whose ances-
tors were the possessors of the Barony of Cowden Knows, in Sel-
kirkshire, renowned in Scottish song, and commemorated in the
pages of Rousseau*.

The Statutes relating to the election of Council and Officers
having been read by the Secretary, and Joseph Smith, Esq. and
Capt. Grover having, with the consent of the Society, been nomi-
nated Scrutators in examining the lists, the votes of the Fellows
present were collected.

The following Gentlemen were elected Officers and Council for
the ensuing year, viz. —

President — The Marquis of Northampton. Treasurer. — Sir John
William Lubbock, Bart., M.A. Secretaries. — Peter Mark Roget,
M.D., Samuel Hunter Christie, Esq., M.A. Foreign Secretary. —
John Frederic Daniell, Esq. Oilier Members of the Council. —
Martin Barry, M.D. ; William Bowman, Esq. ; Sir Thomas M. Bris-
bane, K.C.B. ; Henry James Brooke, Esq.; Robert Brown, Esq.,
D.C.L.; William F.Chambers, M.D.,K.OH.; George Dollond, Esq.;
Thomas Graham, Esq., M.A. ; John Thomas Graves, Esq., M.A. ;
Robert Lee, M.D. ; William Hallows Miller, Esq., M.A. ; Roderick
Impey Murchison, Esq.; Richard Owen, Esq.; Jonathan Pereira,
M.D.; Captain James Clark Ross, R.N.; James Walker, Esq.

GEOLOGICAL SOCIETY.
[Continued from p. 153.]
May 24, 1843. — A paper was read "On the Geology of some
points on the West Coast of Africa, and of the Banks of the river
Niger." By W. Stanger, M.D., F.G.S.

1 . Sierra Leone. — The predominant rock is a highly ferruginous

* Obituary notices of William, Lord Fitzgerald and Vesey, Robert Alex-
ander, Esq., K.C., and Archdeacon Wrangham, were also given in the
President's Address.

218 Geological Society : Dr. Stanger on the

sandstone, not distinctly stratified, rendered vesicular by removal of
the iron on exposure to the weather. The iron occurs in concentric
laminae, and is found in masses occasionally powerfully magnetic.
Under the sandstone is seen, at several places, a stiff aluminous
clay containing fragments of wood. At a section at Kingstown
the sandstone is forty feet thick. Hyperstene rock forms the side of
the fort-hill and the tops of the hills around Sierra Leone. Neither
volcanic nor granitic rocks were observed in the neighbourhood.

2. Liberia. — Monrovia. — The rocks in the neighbourhood of the
Mesurada river are greenstone. Ferruginous sandstone, similar to
that at Sierra Leone, occurs near the government house. The author
saw fragments of gneiss, but none in situ, and was shown a spe-
cimen of large granular granite, said to be found forty miles up the
country.

3. River Sinoo, lat. 5 N., long. 9 W. — On the south side of the
river are small hills of gneiss, cut through in places by veins of
granite running in all directions, and in one place by a vein of trap
two feet wide, running W.N.W. and E.S.E. The author found
greenstone in the neighbourhood passing into hornblende rock, but
did not see its connection with the gneiss. The north bank of the
river is low land covered with sand, in which was found a fragment
of ferruginous sandstone like that at the preceding localities.

4. Cape Coast Castle. — The castle stands on a mass of granite,
which is small-granular, and contains imbedded masses of horn-
blende slate. The felspar is flesh-coloured and in many places mixed
with the quartz, forming a beautiful variety of graphic granite.
About a mile north of the castle mica slate is seen in contact with
and dipping under the granite to the south at an angle of 40°. The
slate is not altered but much decomposed. Both granite and slate
are cut through by veins of quartz ; and in the town, a mass of mica
slate is seen imbedded in the granite, which sends veins into the
slate. In one place a greenstone vein, four yards wide, was seen
traversing the granite, itself again traversed by a vein of granite.
The mica slate is worn into valleys, and the granite stands up in
masses which have been erroneously regarded as erratic blocks.

5. Accra. — The town is built on sandstone which dips to the
S.E., and has joints running W.S.W. and E.N.E. In mineral cha-
racter it resembles the new red sandstone of Liverpool. The surface
of the country about the Salt Lake, which is to the north of the
town and about thirty feet above the level of the sea, is a sandy
clay or loam containing great numbers of shells of the genera A chatina,
Area, Cytherea and Cerithium. At the farm on the hill, fourteen miles
from Danish Accra, the rock is quartz rock, white and red, dipping at
40° to the S.W. and traversed by joints at right angles to the dip.
The joints are redder than the general hue of the rock, which the
author regards as a metamorphic sandstone.

The gold which is met with at Cape Coast Castle, Anamabre
and Accra, is procured from the sand by washing. This sand is
usually white, and contains iron and hornblende. The felspar at
Anamabre is green, and in some places between Accra and Cape

Geology of the West Coast of Africa. 219

Coast Castle it is decomposed into a clay containing sparkling par-
ticles of mica, which are not unfrequently mistaken for gold.

6. Grand Sesters. — The rocks here are gneiss cut through by gra-
nite, as at the river Sinoo. The felspar of the granite is opalescent.

7. Niger. — The Delta is a flat swampy tract composed of clay, sand,
and much vegetable matter, extending to Eboe, a distance of 120
miles from the sea. The banks of the river are elevated only a few
feet above its level. From Eboe to Iddah, a distance of 100 miles,
there is a gradual rise of the country, but still swampy and similar
in constitution to the Delta. At Iddah the first rocks appear. They
are 185 feet high (barom. measure) and are composed of sandstone,
the strata of which are for the most part horizontal, but occasionally
dip at an angle of 3° to the S.E. This sandstone is fine granular,
and composed of transparent particles of white quartz. The upper
beds are highly ferruginous. The strata are cut through by joints
running in all directions. After the most careful search, one fossil
only, and that a very obscure one, was met with in the sandstone.
It resembled a Pollicipes. The cliffs of Iddah are formed by the
outcrop of a ridge of hills running N.E. and S.W. From Iddah to
Kirree the country is composed of sandstone of the same character,
more or less ferruginous in places. The character of the country is
that of elevated table lands, edged by cliffs, bordered by debris. At
Kirree, strata of mica slate, dipping 85° due west, appear standing up
in high masses on the right bank of the river, in which bank, opposite
to Kirree, is the Bird rock, composed of a mass of quartz evidently
imbedded in the mica slate. The mica slate rests upon the granite
composing Mount Soracte and the neighbouring hills, attaining a
height not exceeding 1200 feet. Beaufort Island is formed of gra-
nite which is decomposed so as to leave the surface very rough,
from the projection of felspar crystals. It contains little mica, and
is composed of felspar and quartz with a small quantity of horn-
blende. The soil between the blocks of granite is a rich vegetable
loam. The blocks are piled one upon another like masonry. At
Okazi the granite is more largely crystalline, and contains very beau-
tiful opalescent felspar. The granite extends to Adda Kudda, and
at that place it is mixed up and complicated with gneiss which dips
at an angle of 60° to the S. The gneiss contains veins of granite
running in all directions. Further on, the granite again contains
imbedded masses of gneiss. From Adda Kudda, up the river, as
far as was explored, the country is composed of horizontal sandstone,
generally more highly ferruginous than lower down. At Mount
Stirling the iron occurs in the form of pea-iron ore. The granite
appears to be the central axis, mica slate and gneiss occurring on
both sides, or dipping at great angles. The granite is the line of the
so-called Kong mountains, which in no case were observed higher
than 1200 feet. The sandstone lies unconformably upon the mica
slate. Dr. Stanger considers the phenomena observed on the Niger
to indicate three geological periods : — 1st, the eruption of the gra-
nite and elevation of mica slate and gneiss ; 2nd, the deposition of
the sandstone unconformably on the flanks of the mica slate and

220 Geological Society : Mr. R. Wallace on the

granite; and 3rd, the upraising of the whole country, and the
cutting through, by water, of the granite, slate and sandstone, and
the formation of the Delta by the consequent debris.

" On the Classification of Granitic Rocks." By Robert Wallace,
Esq.

Assuming that granite, syenite, and other granitoid rocks, as they
exist in nature, agree with the definitions of those rocks respectively
given by mineralogists, that is, in being aggregates, though in va-
riable proportions, of certain determinate mineral species ; and taking
for granted the accuracy of the analyses which have been made, by
the chemists in highest repute, of the minerals which enter into the
composition of these aggregate rocks, the author directs his atten-
tion more particularly to the alkaline and alkalino-earthy ingredients
of those minerals ; and, inferentially, of the aggregate rocks into
the composition of which these minerals enter ; and finding that in
certain of these aggregates the alkalies exist without any admixture
of alkaline earth, whereas in others both alkalies and alkaline earths
are contained, he proposes to classify granitoid rocks according to
the above distinction in their chemical ingredients.

Among the alkalies, in addition to potash and soda, he places
lithia ; the alkaline earths which fall under his notice, are magnesia
and lime. In subdividing his two principal classes of the aggregate
rocks, the author also takes into account the fluoric and boracic acids,
which appear to be essential to the constitution of certain of the
component minerals.

Ternary granite, consisting either of quartz, binaxal mica and
felspar, or of the two former minerals and albite, is the first of the
aggregate rocks that comes under the author's consideration. Of
binaxal mica the alkaline ingredients are potash and lithia ; and one
of the essential ingredients of this mineral appears to be also fluoric
acid. Of common felspar the alkaline ingredient is potash; of
albite*, soda ; of glassy felspar, a mixture of potash and soda. Of
ternary granite, therefore, the alkaline ingredients are limited to
potash, soda, and lithia ; the alkaline earths, magnesia and lime, not
entering into its constitution.

The different binary combinations of some two of the three mine-
rals, quartz, binaxal mica and felspar, belong to the second division
of the author's first class of aggregate rocks ; that is to say, of those
which contain an alkali, but not an alkaline earth. The binary com-
binations which he mentions, are —

1. Common felspar and binaxal mica.

2. Compact felspar and binaxal mica, called eurite, whitestone,
and felspathic granite.

3. Common felspar and quartz, which may be either an uniform
mixture of the two minerals, or may consist of imperfect crystals of
one, or the other, or of both of them, and is then called pegmatite,
or graphic granite.

4. Quartz and binaxal mica ; which, if the mica is regularly inter-
* Albite has been found to contain a very small variable proportion of

lime, not exceeding 5 parts in 1000.

Classification of Granitic Rocks. 221

spersed, is called avanturine ; but if it occurs in parallel layers,
forms a passage into mica-schist.

The second class of the author contains those aggregate rocks,
into one or more of the component minerals of which magnesia or
lime enters as an essential constituent ; and in the first division of
this class he places syenite and the other rocks containing some of
the ingredients of ternary granite, with the addition of hornblende,
on the ground that in all the varieties of the latter mineral a trace
has been found of fluoric acid ; and in respect of the presence of this
acid the rocks of this division are allied to the rocks of the first class.

Hornblende contains neither potash, soda, nor lithia; but it
abounds in magnesia and lime.

The principal granitoid rocks into the composition of which horn-
blende enters, are the following : —

1 . An aggregate of quartz, mica, felspar, and hornblende, or sy enitic
granite.

2. An aggregate of quartz, felspar, and hornblende, or syenite.

3. An aggregate of felspar, mica and hornblende.

4 An aggregate of felspar and hornblende. Quartz and horn-
blende is only an incidental variety. Actinolite or hypersthene
sometimes replaces hornblende, and is sometimes superadded to it.
Hornblende is the characteristic mineral of the granitoid rocks of
Scotland.

The second division of the second class of the author consists of
ternary granite, of which the binaxal mica has been replaced by
talc, chlorite, or steatite (which rock has been termed protogine),
or by uniaxal mica. The latter aggregate occurs principally among
volcanic rocks.

Neither talc, chlorite, nor steatite contain lithia, nor fluoric acid ;
but the predominant alkalino- earthy ingredient is magnesia. Uniaxal
mica contains magnesia, but no lime.

The third division of the author's second class of granitoid rocks,
consists of those into the composition of which tourmaline enters,
and this is the characteristic mineral of the granitoid rocks of Corn-
wall. With quartz, felspar and mica it forms the schorly granite ;
and with quartz and felspar, or with quartz alone, it forms the schorl-
rock of some mineralogists.

Tourmaline contains nearly equal quantities of silica and alumina ;
and oxide of iron is an ingredient of most of its varieties. It con-
tains a trace of one or other, or of both of the alkalies, potash and
soda, with a small but variable portion of magnesia, and occasionally
a trace of lime. Boracic acid is its characteristic ingredient.

The author enters into some theoretical views respecting the
origin of the various forms of granitoid rock.

Ternary granite, composed of quartz, felspar (or albite) and
binaxal mica, constitutes, according to his view, the lowest accessible
rock of the earth's original crust.

It has been uplifted and protruded through sedimentary strata at
different periods, from the earliest to the latest age of igneous dis-
turbance. It may have been elevated in a solid state, or in a state

222 Geological Society : Mr. Austen's Additional Note

of partial or imperfect fusion. It may have changed its original
character, either by being heated a second time, and again cooling,
under circumstances different from those which attended its first
consolidation ; or by entering into fresh combinations with the rocks
above it, or with those beneath it. The further the rock is removed
from the reach of any such influences, the nearer does it approach
in character, in respect of its mechanical and chemical structure, to
true ternary granite. Even when granite has been so alteredtas to
assume the character of porphyry or trachyte, the Original character
of the granite out of which those rocks were formed may often be
traced in the gneiss with which those rocks are flanked.

The fine-grained varieties of ternary granite, which are often
found in veins, have probably been fused a second time. The seat
of the binary granites was probably below that of the ternary rock,
but higher than that of the granites which contain alkalino-earthy
substances. Granite containing other substances than quartz, felspar
(or albite) and binaxal mica, has probably been again fused, and
has derived the foreign matters intermingled with it, either from the
sedimentary rocks through which it has been protruded, or from
regions below that of ancient ternary granite. Hence the variations
in modern grariite are almost as numerous as the localities in which
they are found. Thus the granite of Devonshire and Cornwall,
which has been uplifted and protruded through all the stratified rocks
that were incumbent upon it, not excepting even the culm, was in a
fused state in its upper portion when in contact with those stratified
rocks ; and it probably brought up with it extraneous matters from
beneath. Hence the granite of these counties no longer exhibits the
characteristics of ancient granite ; but in some parts porphyritic
granite occurs ; the granitic dykes, or elvans, consist mostly of
eurite ; in other parts we have talcose granite, or protogine, which
produces the China clay ; and schorly granite is generally found
near the contact of that rock with the slates.

The fact that ancient granite sometimes graduates into syenitic
granite, renders it probable that the latter is a modification of the
former.

The substances which invaded the territories of ancient ternary
granite, were probably those which occupied the regions immediately
subjacent to it, while those which lay nearer to the earth's centre
remained comparatively undisturbed.

In general, the conclusion of the author is, that the absence of
mica, or the presence of minerals abounding in magnesia or lime,
or that of metallic oxides, or a transition into syenite, porphyry,
basalt, or volcanic rocks, are indications of an origin of later date
than that of ancient granite.

" Additional note on the Geology of the South-East of Surrey."
By R. A. C. Austen, Esq., Sec. G.S.*

The subdivisions of the beds below the white chalk have been
founded on differences of mineral character or colour, or the acci-

[* Mr. Austen's paper, to which this note is supplementary, has already
appeared in the present volume, p. 65 ; see also su])ra, p. 224. — Edit.]

on the Geology of the South-East of Surrey. 223

dental presence of certain minerals, such as oxides or silicates of
iron, seams of chert or flints, &c. ; and though they may hold good
and prove very useful in the south-eastern parts of England, they fail
when applied to the whole area of the chalk and its subjacent beds,
and will be found to interfere with the grouping of the remains of
the animals which range through this system. Hence it is there
have been so many doubts respecting the positions in the series
which the deposits of several localities should occupy ; as, for in-
stance, those of Blackdown and Haldon in the west of England, and
the Speeton clay of Yorkshire.

Again, the subdivisions founded on mineral character, even when
they are sufficiently marked to produce distinct physical features
over the surface of a district (and which has been much insisted
upon by geologists), will often be found to interfere most inconve-
niently with those derived from a consideration of the included or-
ganic remains : thus no contrast can be greater than that between the
upper and lower chalk ; the latter abounding in huge and varied
forms of Ammonites, Scaphites and Turrilites, — which are altogether
wanting higher up, where the Cephalopods are represented by one
or two species of Belemnite only (passing over the differences which
the other classes present) ; so that seven may nearly represent the
number of species common to the two.

In this instance a great change in the conditions of animal life is
unaccompanied with any very obvious change in the character of the
deposit.

The grey calcareous beds of the lower chalk are underlaid by cal-
careous sands and bright green siliceous strata, forming a well-defined
mineralogical group, and which has been formed into the upper
greensand : but subordinate to these are beds of firestone and thick
bands of limestone, and in these all the Cephalopods of the lower
chalk reappear; so that here a change of some sort, sufficiently
great to produce very different deposits, was not attended with any
sensible change in the form of animal life.

The topographical arrangement of these several groups in an as-
cending order is as follows : —

The Neocomian group, or the equivalent of that for which the
French and Swiss geologists have adopted that name, is found only
within the Wealden denudations, and rests everywhere, in the south-
east of England, on the blue Wealden clays, which were the central
deposits of that ancient estuary.

The Speeton clay of Phillips has been referred to the gault, be-
cause it contains a greater number of species in common with that
group than with any other ; but the number is very small. Of the
species supposed to be peculiar the Corbula punctum is generally
quoted from the lowest beds of the French cretaceous group ; and
in addition, M. D'Orbigny has ascertained that the Hamites pli-
catilis belongs to the genus Crioceras, whilst the Hamites intermedins
and beanii are both species of Ancyloceras, a genus which is cha-
racteristic of the lowest beds of the cretaceous series. To these
we may add Spatangus retusus ; so that it becomes very probable

224- Geological Society : Dr. Fitton on the

that the Speeton clay may also be the equivalent of the lowest ar-
gillaceous Neocomian strata of the chalk series of the south-east of
England.

The lower greensand of the south-east of England, as round the
Weald and in the Isle of Wight, rests on the Neocomian group ; and
it is when so placed that it attains its greatest thickness : it does not
extend westward, but thins away beneath the great expanse of chalk
of the counties of Hants and Wilts. It reappears a little south of
Tets worth, and increases in thickness in its extension to the north-
east through Cambridgeshire. In this part of its course it out-
spreads the freshwater deposits, and rests unconformably upon sub-
divisions of the oolitic series.

The gault, though inferior in thickness to some of the other
groups, is the best horizontal line by which they may be severally
arranged, both on account of the well-defined lines by which it is
separated from the groups both above and below it, and also from
the peculiar fossils it contains. It occurs round the western district
and in the Isle of Wight, immediately above the ferruginous sands, It
reappears from beneath the chalk at its escarpment at Shaftsbury, and
in the Vale of Wardour, where it has been fully traced out by Dr. Fit-
ton, but cannot be identified beyond there. In the Vale of Wardour,
instead of following upon the lower greensand, it occurs upon the
marginal beds of the Wealden as well as upon Portland and Kimme-
ridge strata. As was noticed with respect to the lower greensand, the
gault also seems wanting along a considerable interval, but reappears
about Tetsworth, and acquires its greatest thickness in Cambridge-
shire.

Reliance upon the mineral character of the gault, or rather of one
particular portion of it, viz. the argillaceous, has caused it to be
overlooked in its extension westward, over the counties of Dorset
and Devon. The lower beds of the sands which cap the hills from
Lyme to Sidmouth belong to the gault, and the shingle bed, which
the author has noticed as occurring in this portion of the gault series,
and which may easily be seen in Salcome Hill near Sidmouth, marks
its upper limit. The pebbles he believes have been derived from the
Portland sands of Dr. Fitton.

The interval along which neither the gault nor lower greensand
are to be found is not owing, as is sometimes the case, to the sub-
stitution of one set of beds for another, but will be found to corre-
spond exactly with the rise of the older strata from Frome westwards,
and which elevation is of earlier date than any portion of the creta-
ceous series.

Everywhere intermediate between the chalk and the gault is the
complex group (the upper greensand) noticed in the preceding page.
In its extension west, this group becomes wholly siliceous, and forms
the upper portion of the Blackdown range, and the entire thickness
of the Haldon greensand, and the other deposits to the west. ■

" Observations on part of the Section of the Lower Greensand, at
Atherfield, on the coast of the Isle of Wight." By W. H. Fitton,
M.D., &c.

Section of the Lower Greensand at Atherfield. 225

The author having been present during the reading of Mr. Aus-
ten's paper " On the South-cast of Surrey," on the 5th ultimo,
stated verbally his belief that the deposits which that gentleman there
proposes to distinguish as the " argillaceous or Neocomian " division
of the subcretaceous series, must be the same as that which he himself
had described*, as constituting the lowest portion of the lower green-
sand at Atherfield, in the Isle of Wight : but not having seen the
place for more than sixteen years (1826), and at a time when the
section was in a great part concealed by masses of ruin, he was
desirous of examiniug it again. This paper contains an account of
what he has recently observed there.

The time of the author's late visit to Atherfield was very fortu-
nate ; the sea, during severe gales having previously cleared away,
not only a great part of the ruin which formerly concealed the base
of the cliffs, but having entirely removed the shingle of the beach
to a most unusual extent ; so that the junction of the Wealden with
the lower greensand was distinctly exposed for several hundred yards,
while a very large surface of the adjacent strata, washed perfectly
clean, was visible at low water, on both sides of it.

§_ The strata composing the section thus beautifully exhibited,
were the following : —

i . Weald clay, with the usual characters ; which it is not the object
of this paper to describe in detail. The very uppermost beds here
consist of slaty clay, and contain some characteristic fossils of the
Wealden, especially Cyclas media, and small Paludince ; and along
with these, at the top of the freshwater strata, were Cerithia, probably
of a new species, with one or more thin-shelled oysters or Gryphcete
in comparatively smaller number. These fossils occur within a very
few inches from the junction with the sand above the Wealden ; so
that it would be possible, with care, to obtain portable masses, in-
cluding both the Weald clay with its characteristic species, and
part also of the incumbent mass with its marine shells.

2. The junction, which here occupies not more than six or eight
inches in vertical thickness, is formed by an alternation or interjec-
tion of greenish -grey fine sand among slips or slices of the dark Weal-
den shale. The lowest portion of the next bed (3) which rests upon
this sand includes a large quantity of a kind of gravel, containing
numerous fragments of fish-bones.

3. The beds immediately above the sand at the junction (2), con-
sist of a tough, greenish mudlike mass, which becomes grey in
drying, and seems to be an intimate mixture of clay and sand. It
is not more than from 1\ to 3 feet in thickness ; and at the top it is
very closely connected with the lower part of the indurated stratum
(4) : but after exposure even for a short time to the air and sea, the
soft matter of (3) is rapidly removed, leaving the firm mass of (4)
detached and prominent ; and this being undermined, appears upon
the shore in rudely quadrangular detached blocks.

The fossils of the lowest clay (3) appear to be the same, though the
species are less numerous, with those of (4) above it. The most re-
* Geol. Trans., 2nd Ser. vol. iv. p. J96, &c»

Phil. Mag. S. 3. Vol. 24. No. 1 58. March 1 844. Q

226 . Geological Society: Dr. Fitton on the

markable amongst them is Perna Mulleti. Mya and Panoptea, pro-
bably of more than one species, are especially numerous, even close
to the very junction of the Wealden : and with these were Area
Raulini, Mytilus lanceolatus, Pinna sulcifera, Pecten quinquecostatus,
and P. striato-costatus (Goldfuss).

4. The bed of firm, subferruginous and somewhat calciferous stone
which next succeeds, formed, when the author first examined this
place (in 1826), the most prominent feature of the cliffs : everything
beneath, to a depth of about ten feet, being deeply concealed by
ruin. It was now distinctly seen that the bottom of this remarkable
bed is not more, at the utmost, than three feet from the top of the
Wealden. By its greater firmness it contributes to sustain the cliff,
the mass of which it traverses obliquely in rising westward ; and
from the base of the projecting land or point of Atherfield it runs
out into the sea, declining very gradually, and forming a dangerous
reef called Atherfield ledge. Though its average thickness is not
more than 2| feet, this bed abounds very remarkably in fossil remains,
among which are several of the species figured by M. Leymerie in
his memoir on the geology of the Aube, and of those found by Mr.
Austen at Peasemarsh, in Surrey.
Ostrea (new species). Pecten quinquecostatus.

Spatangus (three or more species) . striato-costatus.

Mya mandibula. obliquus {inter stria t us

Pholadomya acutisulcata (Leym.). Leym.).

Prevosti (Leym.). Gryphcea sinuata.

Corbula striatula. Terebratula sella.

Sphcera corrugata. (three or more other sp.).

Thetis minor. Orbicula Icevigata (Deshayes).

Trigonia dcedalea. Natica (Ampullaria) Icevigata

Fittoni. (Leym.).

(two new species). Pleurotomaria gigantea.

Gervillia aviculoides. Nautilus radiatus.

Pinna sulcifera. Ammonites Deshayesii (Leym.).

Perna Mulleti. (four or five species) .

— — alceformis. with many other genera.

5. Immediately above the stone-bed (4), is a thick mass of nearly
uniform clay, with many of the properties of fuller's earth. It is di-
vided apparently into two principal strata, each not less than fifteen
feet in thickness ; and these seem to be succeeded upwards by other
argillaceous beds, which were so much obscured by debris as not
to be traceable. The fuller's earth is either of a lavender-blue or of
a drab colour ; it contains concretional portions (not seen in situ),
almost composed of fossils, including Thetis minor, Rostellaria bica-
rinata, with several small univalves. Other masses, also of uncertain
place, occur in the fuller's earth, containing numerous Crustacean re-
mains, especially of Astacus, of more than one species. Pinna sulci-
fera abounds near the bottom of the lower bed, and Ammonites Des-
hayesii, with other Ammonites, is frequent.

§. From the preceding lists, it is evident that an accumulation of
fossils, very remarkable for their number and variety, exists at

Section of the Lower Greensand at Atherfield. 227

Atherfield, in what has hitherto been considered as the bottom of
the lower greensand. But while some of these fossils have been
found, in England, only at Peasemarsh and at this place, they are
here accompanied by others, which have a considerable upward range
in the subcretaceous strata.

§. The cliffs on the shore between Atherfield and Rocken End, on
the east of which latter place the lower greensand first rises, contain
comparatively a much smaller number of fossils than the lowest
strata just mentioned. Those which are found here, occur chiefly in
concretions, due probably to the presence of the organized remains
which they include ; but lines of such nodules appear to be distri-
buted at intervals throughout the whole series, as far at least as the
middle of the cliff at Blackgang Chine. Of these ranges the follow-
ing are some of the most prominent, —

a. A conspicuous group, composed of two parallel ranges of nodules,
rises on the shore about half a mile east of Atherfield point, and there
forms a slight prominence called " the Crackers," (from the sound
caused by the sea during rough weather beneath the undermined
cliffs). These nodules consist of a rough concretional calcareous
rock (like coarse Kentish rag), which includes in great numbers,
Gervillia aviculoides, Thetis minor in beautiful preservation : a pro-
fusion of Terebratulte, especially T. sella, Ammonites Deshayesii,
Trigonia dccdalea, and other fossils ; — most of which, it is supposed,
occur also in the quarry-stone of Hythe.

b. JExogyra sinuata, with some of the principal varieties of that
species figured by M. Leymerie, is of frequent occurrence, both in
detached clusters, and in somewhat continuous ranges, throughout
the cliffs between Atherfield and Blackgang Chine.

c. Very large and beautiful specimens of Crioceras (Ancyloceras,
D'Orbigny), Scaphites, and Ammonites, have also been found in
the face of the cliffs, or within the Chines, on this part of the shore.
Of these, Crioceras Bowerbankii* was found in Ladder-chine; Sca-
phites gigas loose upon the shore, its precise situation not having
been ascertained f.

§. The author points out, as deserving of especial notice, the rapid
and remarkable reduction in the proportion of calcareous matter in
the lower greensand of the Isle of Wight and of Surrey, when com-
pared with the calciferous district of Kent, from the coast to the
west of Maidstone. No continuous beds of limestone occur in the
Atherfield section ; while the Kentish rag in the quarries at Hythe
and Maidstone cannot be far short of a hundred feet in thickness.

§. Sandown Bay. — A section corresponding to that of Atherfield,
is visible on the east of Sandown Bay, between the fort and the
chalk of Culver Cliff. The author had formerly seen there a bed

* Sowerby, Geol. Trans. 2nd Series, vol. v.

f Some fine specimens of these large fossils are in the lawn of Capt. Peter-
son, near Blackgang Chine; in the museum of Mr. A. J. Hambrough, atSteep-
hill Castle ; and in the splendid collection of Isle of Wight fossils, deposited
by Capt. Ibbetson in the museum of the Polytechnic Institution.

Q2

228 Geological Society : Dr. Fitton on the

of concretional stone immediately above the Wealden and subjacent
to a bed of fuller's earth ; and on examining the place recently, in
company with the President (Mr. Warburton), the resemblance of
the two sections was confirmed, and some of the Atherfield fossils
obtained from the Sandown bed. The President has since been
there alone, and has been very successful in obtaining from the stony
masses exposed at low water, specimens of the most characteristic
fossils, especially of Perna Mulleti, with some new species of other
genera: — Panopaa,Astarte Beaumontii (Leymerie), Gervillia anceps},
Perna Mulleti, Perna alceformis, Spheera corrugata ?, Sphcera (new sp. ?),
Gryphtea sinuata, &c. Beneath this bed at Sandown Bay, as at
Atherfield, is a thin stratum of marine fossiliferous clay.

§. Since the recent examination of the coast at Atherfield, the
author has obtained information respecting the corresponding strata
in some other places. —

Surrey. — Mr. Murchison, in crossing the section of the lower
greensand, exposed by the cuttings on the Dover railway, near
Redhills in Surrey, perceived that the junction of the greensand with
the Wealden must have been traversed near that place* ; and having
mentioned this observation to the President and Dr. Buckland, these
gentlemen were so fortunate as to detect there several large con-
cretional masses, brought out during the progress of the works, and
evidently corresponding in situation with those of Peasemarsh dis-
covered by Mr. Austen. This latter gentleman, with the President
and the author, have since visited the place again ; and from these
united labours a collection has been obtained, including some of the
most characteristic of M. Leymerie's Neocomian species, with a few
belonging also to the quarry-stone of Hythe. — Area Raulini, Pano-
p&a depressa, Pholadomya acutisulcata (Leymerie), Pecten obliquus
(interstriatus), Pinna sulcifera, Gervillia aviculoides, Perna Mulleti,
P. alctformis, Trigonia dadalea, T. Fittoni, Gryph&a sinuata, Nau-
tilus radiatus.

Vicinity of Pulborough, Sussex. — Mr. Martin, of Pulborough, has
mentioned the occurrence at Stopham brickyard (where the junction
with the Wealden was to be expected), of certain fossils, in abed of
clay at the bottom of the lower greensand. A collection of these,
which he has recently sent to the author, includes Area Raulini, Pho-
ladomya acuticostata, Panopcea plicata, Pleurotomaria gigantea, Os-
trea carinata, Nautilus radiatus, fossil wood with Gastrochcena,
vertebra? and skin of a Lamna.

Hythe, in Kent. — The section of the subcretaceous groups on the
coast from Folkstone to Hythe being one of the most complete
hitherto discovered, it is a matter of great interest to ascertain
the relation of the component strata to those of Atherfield above
referred to. The junction, however, of the Wealden with the green-
sand, so distinctly exposed at Atherfield, is unfortunately concealed

* The precise spot is on the top of the southern bank of the railway,
south-west of a bridge over which a road crosses to Roberts-hole farm, of the
Ordnance map.

Section of the Lower Greenland at At/terfeld. 229

at Hythe by debris of unknown depth, and everywhere covered
with vegetation*.

The only intimation hitherto received by the author of the exist-
ence of any lower stratum containing fossils differing from those
of the Hythe quarries, has come from Mr. Hills, now curator of the
Institution at Chichester, who has long been possessed of specimens
found near Court-at-street, his former abode in Kent, in a " blue
sandy clay below the bottom of the quarry stone." Amongst these are
a large Ostrea, or Hinnites, like a species found at Atherficld, and
Pholadomya acuticosiata (of Leymerie).

Under these circumstances it became a question of great interest
to determine the nature of the unknown interval at Hythe ; and on
going to the place with that object, the author found that Mr. Simms,
who conducted the works upon the South Eastern Railway, espe-
cially the tunnel at Saltwood, had been for some time engaged in
borings and measurements, with a view to a complete section of
the country through which the railway and tunnel had passed. Mr.
Simms was induced to extend his operations to the bottom of the
subcretaceous groups ; and finally determined on sinking a shaft
from the bottom of the deepest quarry, continuously down to the
Weald clay, for the purpose of obtaining a more satisfactory view
of the fossils of the lowest beds. This undertaking was in progress
when the present paper was read, and the results will be laid before
the Society.

§. From the facts above stated, it is evident that the deposit of
Atherfield, in the Isle of Wight, like that which contains the fossils
of Peasemarsh enumerated by Mr. Austen, belongs to the lower
greensand : — both being unequivocally superior to the Wealden clay.
If, therefore, these fossils are characteristic of the Terrain Neocomicn,
the hypothesis which supposes that formation to be contemporaneous
with the Wealden can no longer be maintained.

The author, however, is far from denying that a marine equivalent
of the Wealden may exist f. But whenever such an equivalent shall
be discovered, — since it must be distinct from the Lower greensand

* The nearest point to the stone quarries, where the author had seen
the Wealden beds (in 1823), is thus mentioned in Geol. Trans., 2nd Series,
vol. iv. p. 124. — 'The shore beneath the town consists of soft bluish clay,
' which has the character of river mud, and differs much from the uniform
' slaty clay of the Wealden. But the latter (Weald clay) has been cut
' into in sinking wells above the main street of Hythe, which in some in-
' stances have gone to the depth of seventy-five feet, entirely in clay. In
' one of these wells the succession was thus : — beginning at a point about
' sixty feet beneath the bottom of the lower greensand.

i 1. Soil 2ft. 6in.

'2. Reddish tough clay 6 to 7 ft.

' 3. Greenish sandy clay in thin beds, alternately of dark \ . . „
and lighter hues J

• 4. Blue, uniform, slaty clay, containing Cypris about a \

foot from the top /

' 5. A band composed of argillaceous iron ore, abounding ) « ,

in Paludina elongata and Cypris /

t See Geol. Trans., 2nd Series, vol. iv. p. 396.

230 Geological Society.

and the Neocomian,: — he thinks it ought to be regarded as a new
deposit, and to receive a peculiar name.

The paper was illustrated by a section and a sketch of the coast
near Atherfield; and it concludes with an expression of acknow-
ledgement to Mr. Austen, for the new impulse which his inquiries
have given to the study of the subcretaceous series in England.

June 7, 1843. — A note was read from W.C.Trevelyan, Esq., F.G.S.,
"On scratched surfaces of rocks near Mount Parnassus."

On the way from Megara to Corinth the road descends to the
border of the sea at a part named, on account of its badness, icaKt
(TKaXa (the ancient Scironian rocks). It then runs along the base
of the cliffs where the limestone bed is nearly vertical ; and for above
200 feet in length and about 50 in height, wherever it is protected
from the weather, it is highly polished and scratched, several of the
scratches extending for several feet, so as to be nearly parallel with
each other and vertical. Where they are not weatherworn, Mr,
Trevelyan compares their aspect with those on the polished limestone
of the Jura near Neufchatel, which they also resemble in texture and
colour. Not having succeeded in detecting glacial phenomena at much
higher elevations on Mount Parnassus, Mr. Trevelyan considered,
that in this latitude, and at such a low level, the scratches could not
be attributed to that cause or to floating ice. Having found a portion
of rock apparently in its original situation in contact with the polished
surface, he was led to conclude that this was a case of " slickenside,"
perhaps the effects of an earthquake ; and that the scratches may have
been produced by particles of sand or chert between the two surfaces
when they were put in motion.

The only place in Greece where the author observed apparent
marks of glacial action was at the opening of a gorge on the south-
east flank of Mount Parnassus, above the town of Daulia (the an-
cient Daulis), where there are extensive mounds of gravel, debris and
boulders, evidently derived from the upper part of the gorge, and
resembling in form both longitudinal and transverse moraines, and
including occasionally small lakes or pools. Not finding however
any evidence of glaciers, Mr. Trevelyan concluded that the cause
might be found in storms, melting of snow and avalanches, of which
numerous recent evidences were seen in the neighbourhood.

"On Ichthyopodolites, or petrified trackways of ambulatory fishes
upon sandstone of the Coal formation." By the Rev. W. Buckland,
D.D., F.G.S.

These impressions were discovered by Miss Potts of Chester, on
a flagstone near the shaft of a coal-pit at Mostyn in Flintshire, and
were communicated by her to Dr. Buckland, with a remark on the
novelty of footsteps in any stratum older than the new red sand-
stone. As they present no trace of any true foot to which long
claws may have been attached, Dr. Buckland rejects the notion of
their having been made by a reptile. They consist of curvilinear
scratches disposed symmetrically at regular intervals on each side of
a level space, about two inches wide, which in his opinion may re-
present the body of a fish, to the pectoral rays of which animal he

Mr. Kaye on Fossilifcrons Beds in Southern India. 231

attributes the scratches. They follow one another in nearly equi-
distant rows of three scratches in a row, and at intervals of about
two inches from the point of each individual scratch to the points
of those next succeeding and preceding it. They are all slightly
convex outwards, three on each side of the median space, or supposed
place of the body of the fish. Each external scratch is about one inch
and a half in length ; the inner ones are about half an inch, and the
middle one about an inch long. These proportions are pretty constant
through a series of eight successive rows of triple impressions on the
slab from the Mostyn coal- pit. The impressions of the right and left
fin-ray are not quite symmetrically opposed to each other on a straight
line of progression ; but the path of the animal appears to have been
curvilinear, trending towards the right : each impression or scratch
is deepest on its supposed frontal side, and becomes more shallow
gradually backwards. All these conditions seem to agree with the
hypothesis of their having been made by three bony processes pro-
jecting from the anterior rays of the pectoral fin of a fish. They are
not consistent with conditions that would have accompanied the im-
pressions of claws proceeding from the feet of any reptile.

Dr. Buckland refers to the structure of existing Siluroid and Lo-
phoid fishes, and of the climbing perch (Anabas scandens), and Has-
sar (Doras costata), as bearing him out in the conclusions he has
come to regarding those markings. He also refers to the observa-
tions of Prof. Deslonchamps, on the ambulatory movements under
water of the common Gurnard, as confirmatory of his views. He
has been informed of a slab of coal sandstone bearing similar mark-
ings in the museum of Sheffield ; and remarks, that there are several
fossil fishes of the carboniferous system approximating the characters
of Gurnards, and capable of making such markings as those described.

" Observations on certain Fossiliferous beds in Southern India."
By C. T. Kaye, Esq., F.G.S., of the Madras Civil Service.

The beds described in this paper are found at three localities ; viz.
Pondicherry, Verdachellum and Trinchinopoly.

1. Pondicherry. — This town, like Madras, is situated on a very
recent formation of loose sand, which extends for a considerable di-
stance along the eastern coast of India, and which in many places
contains marine shells in such abundance that they are dug up and
burnt for lime. They are all species which now inhabit the Indian
seas, such as Pyrula vespertilio, Purpura carinifera, Cardita antiquata,
Area granosa and Area rhombea. The sand is usually bounded by
granite, which appears at the surface at Sadras, Madras and other
places. Immediately beyond the town of Pondicherry, however, the
recent beds rest upon some low hills of red sandstone. A bed of
limestone containing numerous fossils succeeds, and at the distance
of four miles due west the red sandstone is again met with and there
abounds with silicified wood. At about sixteen miles from the sea
the sandstone is bounded by hills of black granite.

The surface of the country does not offer any section exhibiting
the relative positions of the limestone and sandstone. In the former,
numerous fossils in a high state of preservation were discovered by

232 Intelligence and Miscellaneotis Articles.

Mr. Kaye, including species of Baculites, Ammonites, Nautilus, Ha~
mites, Ptychoceras, Ancyloceras, Voluta, Cypreea, Conus, Tornatella,
Rostellaria, Pyrula, Aporrhais, Trochus, Solarium, Natica, Eulima,
Scalaria, Cerithium, Turritella, Dentalium, and Calyptrata ; Ostrea,
Exogyra, Spondylus, Pecten, Trigonia, Mytilus, Pinna, Area, Pectun-
culvs, Nucula, Cardium, Isocardia, Anatina, Cyther&a, Solen, Phola-
domya, Clavagella, Lutraria and Terebratula. Also some fishes' teeth,
Echinodermata and corals, accompanied by wood (calcareous) bored
by Teredo.

The fossil wood found in the sandstone exhibits no traces of worm-
borings, and occurs in the form of trees denuded of their barks, some
of them as long as 100 feet, and all apparently Conifercc.

2. Six miles from Verdachellum in Southern Arcot, about forty
miles from the coast and fifty from Pondicherry, the valley of the
river is formed of a limestone which underlies the sandstone and con-
tains marine fossils, including species of Ammonites, Nautilus, Mela-
nopsis ?, Pleurotomaria, Natica, Pecten, Area, Artemis, Modiola, Exo-
gyra, Lima, Cardita, Cardium, Lutraria and Terebratula.

3. Trinchinopoly. — In this district, at about thirty miles from the'
town of the same name, one hundred from Pondicherry, and sixty
from the sea, is a limestone formation which Mr. Kaye was unable
to visit in person, but from which he procured a quantity of fossils
belonging to twenty-seven species of various genera, including Na-
tica, Turritella, Triton, Fusus, Pyrula, Voluta, Melanopsis ? (same spe-
cies as at Verdachellum), Aporrhais, Strombus, Mactra, Psammobia,
Area, Pecten, Ostrea, Cythercea and Cardium. A fragment of an
Ammonite accompanied them.

None of the species appear to be common to the three deposits.
Three species are common to Trinchinopoly and Verdachellum.
From the latter locality there are 28 species of mollusca identical
with lower greensand fossils found in Britain. A single species
appears to be identical with one of those from Pondicherry ; but none
of the testacea from the last mentioned locality agree with those
from Trinchinopoly. The greater part of those from Pondicherry
appear to be undescribed forms. Accompanying the very remarkable
assemblage of molluscan genera at the latter locality was a single
vertebrata of a Saurian, which Professor Owen regards as most nearly
resembling that of Mosasaurus.

Mr. Kaye presented to the Society a series of the fossils from the
several beds, all in the most beautiful state of preservation.

-
XXXVI. Intelligence and Miscellaneous Articles.

AN EXPERIMENT IN PROOF OF THE LATENT LIGHT IN
MERCURY. BY PROFESSOR MOSER.

THE following simple experiment affords such an excellent proof
of the existence of latent light in mercury, and is of such interest,
that I am induced to give publicity to it without waiting to complete
the series to which it belongs : —

Iodize a silver plate, and then heat it over a common spirit-lamp

Intelligence and Miscellaneous Articles. 233

for about a minute. The iodide of silver first becomes darker, and
then milk-white. This white substance is very sensitive to light,
and is in this respect little inferior to any known. By exposure to
light, and indeed by all of its colours, it is converted into a steel-
gray. The plate must therefore be protected from the direct light
of the sky, and the experiment carried on in the back part of the
room. When cold it is placed behind a cut-out screen, which may
be at the distance of a line from the plate over mercury which is
heated to 60° R., and the temperature allowed to fall to 30°. When
the plate is now removed, it has become steel-gray wherever the
vapour of mercury had access, and in this manner the image of the
aperture of the screen is obtained precisely as if ordinary light had
fallen on to the plate. Although the condensed vapour of mercury
is white, yet the action of its latent light preponderates in this case
and determines the colouring.

Heat acts no part here, for it has not the power of rendering the
white substance steel-gray ; nor can there be any question of chemi-
cal rays with this white substance, for all the rays of the spectrum
convert it into steel-gray. — Konigsberg, July 1843.

ON THE EQUIVALENT OF ZINC. BY MONS. P. A. FAVRE.

The author remarks that the hypothesis of Dr. Prout, submitted
to experiment by M. Dumas, has become in his hands a subject of
the highest importance. The experiments published by M. Jacque-
lain to determine the equivalent of zinc induced M. Favre to under-
take the subject ; the conviction expressed by M. Jacquelain, that
the number 414, stated by him, is a minimum, would inevitably re-
move zinc from the series of the multiples of hydrogen.

To clear up this subject M. Favre analysed several specimens of
oxalate of zinc prepared with the greatest care, and he also deter-
mined the quantity of water decomposed in oxidizing a given weight
of zinc. The gaseous products of the decomposition of oxalate of
zinc were passed over oxide of copper heated to redness, and the
carbonic acid formed was condensed ; knowing the weight of this,
and the corresponding weight of the residual oxide of zinc, all the
requisites for determining the equivalent of zinc are obtained, that
of carbon being already known. This mode of experimenting has
the advantage of supplying all the elements for calculation by one
operation only ; besides which it allows of deducting the accidental
water which the salt may contain ; the experiments executed on this
plan yielded the following numbers as the equivalent of zinc ; the
quantity of carbonic acid obtained was, in some cases, from about
123 grains, of oxalate, and never from less than 77 grains.

I. II. III. IV. Mean.

412-58 412-25 413-36 412'45 412-66

These numbers lead to the number 33'01 as the equivalent of zinc,
that of hydrogen being reckoned unity.

The second series of experiments was performed by burning, by
means of oxide of copper, the whole of the hydrogen obtained by de-
composing water with sulphuric acid and zinc, the metal being pure

234 Intelligence and Miscellaneous Articles.

and its quantity noted ; the water formed by the combustion of the
hydrogen was collected and weighed in absorption tubes.

The zinc employed was purified by M. Jacquelain's method, and
to render it attackable by sulphuric acid it was placed in a platina
vessel ; the quantity of zinc employed in these operations was not
less than 246 grains, and amounted in some cases to 1047 grains.

Assuming 12'5 as for the equivalent of hydrogen, the following
were the numbers obtained, in these experiments, for that of zinc :
I. II. III. Mean.

412-27 411-77 41242 412-16

These figures evidently represent a multiple of the equivalent of
hydrogen by 33. They agree very well with those obtained by the
first method :

Equivalent by the first method .... 41 2' 63
Equivalent by the second method . . 4 12- 16

Mean 412-395

The equivalent of hydrogen being 1, that of zinc will then be repre-
sented by 32-991, very near 33. — Journ. dePh. et deCh., Janvier 1844.

MODE OF DISTINGUISHING ZINC FROM MANGANESE WHEN
DISSOLVED IN AMMONIACAL SALTS. BY M. OTTO.

When a solution of hydrochlorate of ammonia containing the chlo-
rides of zinc and manganese is rendered alkaline by a small quantity
of ammonia, and a little hydrosulphuric acid is added, a white pre-
cipitate of sulphuret of zinc free from sulphuret of manganese is
formed ; in order that the latter may be produced, a larger quantity
of hydrosulphuric acid must be added. It is always easy to distin-
guish and separate these two sulphurets one from the other ; to
effect it, excess of acetic acid must be added to the liquid, by which
the sulphuret of manganese will be dissolved, while that of zinc will
remain unacted upon. Thus to determine whether iron contains any
brass, the metal is to be dissolved in aqua regia, and ammonia is to
be added to the acid solution to precipitate the peroxide of iron ;
into the liquor, filtered and rendered acid, a current of hydrosulphu-
ric acid is to be passed, which precipitates the copper in the state of
sulphuret ; after its separation ammonia is added to the menstruum,
and, as this contains hydrosulphuric acid, a white precipitate of sul-
phuret of zinc is formed, which is insoluble in acetic acid. M. Otto
objects to the employment of hydrosulphate of ammonia, as it
almost always contains persulphuret, the sulphur of which is preci-
pitated by the acetic acid, and this being white and insoluble in
acetic acid, may be confounded with sulphuret of zinc. M. Wack-
enroder has recommended the formation of sulphuret of manganese
as a means of separating it from all other metals, on account of its
solubility in acetic acid. — Jour, de Pharm. et de Ch., Janvier 1844.

PREPARATION OF PROTIODIDE OF IRON. BY M. MIAI.HE.

The author remarks that it is generally supposed that the above-
named salt cannot be prepared in contact with the air and obtained
in a solid state in a state of purity, and he admits that in fact it ge-

Intelligence and Miscellaneous Articles. 235

nerally consists of a mixture of variable quantities of protiodide, per-
iodide and sesquioxide of iron and free iodine.

M. Mialhe states that the solid protiodide is easily prepared, even
in contact with the air, by the following process : — prepare, in the
usual manner, a solution of protiodide of iron, and evaporate it in a
porcelain capsule, containing iron turnings or wire, quite free from
oxide ; the evaporation must be carefully conducted, and continued
until a small quantity of the salt being taken up by a glass rod and
deposited on a cool substance, it instantly solidifies. When this state
of concentration is effected, the protiodide of iron is to be carefully
poured off from the iron in the capsule, on a plate of glass or porce-
lain, and immediately afterwards introduced into small well-stopped
dry bottles.

The properties of the protiodide of iron thus prepared are, that it
is in the form of brittle scales of different degrees of thickness, which
when broken exhibit evident traces of crystallization ; it is extremely
deliquescent ; its solution is greenish ; it is precipitated white by
ammonia, and bluish- white by ferrocyanide of potassium ; when
triturated with starch no blue colour is produced. — Journ. dePharm.
etde Chim., Janvier 1844.

ON CHLORAZOTIC ACID. BY M. BAUDRIMONT.

M. Baudrimont remarks, that although aqua-regia has been known
for some centuries, and that frequent use is made of it, it has been
subjected to but few researches. It is generally supposed that it
owes its property of dissolving gold to the presence of free chlorine ;
in 1831, however, Mr. Edmund Davy published a memoir, which tends
to prove that the active product of aqua-regia is a peculiar gas formed
of equal volumes of chlorine and nitric oxide gases, uncondensed ; he
states the specific gravity of this gas to be 1*759, and he has
given it the name of chloronitrous gas. The process by which Mr.
E. Davy obtained this gas was by acting upon fused chloride of po-
tassium or sodium by concentrated nitric acid. The nature of the
substances reacting on each other, clearly prove that it is impossible
to obtain this gas unmixed with chlorine, as shown by the following
equation : —

4Az06H + 3ClNa = 3Az06Na 4- Az O2, CI9 + CI.

The presence of chlorine in the supposed gas from aqua-regia
preventing a proper examination of its qualities, the following were
the results of the experiments made on this subject by M. Baudri-
mont : —

When a mixture of two parts by weight of nitric and three of hy-
drochloric acid of commerce is made, a red gas begins to extricate at
about 1SG° F. If this gas be passed into a U-shaped tube, placed in
powdered ice, the condensable portions of it are separated. Expe-
riment showed that the first portions of the gas are mixed with hy-
drochloric acid, and that the latter only are sufficiently pure ; this
gas does not redden dry litmus paper, but decolorizes it after some
hours ; when it is moist the paper is reddened by it ; at 32° F. water
dissolves 0-3928 of its weight, or 121 times its volume ; the solution

236 Intelligence and Miscellaneous Articles.

"6

is of a bright red colour, and its specific gravity is 1*1611. When
inclosed in a tube hermetically sealed, it is not decolorized by long-
continued exposure to the solar rays, and it possesses all the other
known properties of aqua-regia.

Chlorazotic acid gas attacks several metals, such as gold and pla
tina ; arsenic and antimony, reduced to powder, when thrown into
it, burn with the extrication of light ; but it is a singular circumstance,
that it has scarcely any action on phosphorus, even when melted
by heat ; the active product of aqua-regia does combine directly with
metallic oxides ; it gives a chloride and a nitrate by a reaction which
is readily explained. When chlorazotic acid gas is exposed in small
tubes to the cold of a mixture of common salt and ice, it liquefies,
and the fluid yielded has the following properties : it is of a deep red
colour, but much less so than hypochlorous acid ; it boils at about
20° F.*; its specific gravity at 46° F. is T3677 ; the specific gravity of
the gas is about 2'49. This liquefied gas attacks all metals which are
brought into contact with it ; with pulverulent silver, derived from
the reduction of the chloride, it explodes, and disappears immediately ;
it evaporates without acting upon phosphorus.

By analysis chlorazotic acid gas appears to be formed of

Equivs.

Chlorine 65-0 2 = 72

Oxygen 22'4 3 = 24

Azote 12-6 1 = 14

100-0 Equivalent 110

The composition of this product may, according to M. Baudrimont,
be represented by a formula resembling that of anhydrous nitric acid,
for Az03 Oo resembles Az03 Cl„ ; this being the case, and consider-
ing the previous discovery of chloro- sulphuric acid, M. Baudrimont
proposes to call the gas of aqua-regia chlorazotic acid, although in
reality it is not an acid, since it does not saturate bases : 1 equiva-
lent of chlorazotic acid corresponds to 6 volumes of vapour.

The liquefaction of chlorazotic acid, the boiling point of the lique-
fied gas, its direct solubility in water, its action on metallic oxides,
evidently indicate that it is a substance of a peculiar and well-de-
fined nature, and that its composition corresponds to that of anhy-
drous nitric acid. — Journ. de Pharm. et de Chim., Janvier 1844.

ANALYSIS OF BEAUMONTITE. BY MONS. A. DELESSE.

M. Levy has given, in honour of M. Elie de Beaumont, the name
of beaumontite to a very rare mineral found in the United States ;
it crystallizes in the form of a right jmsm with a square base ; the
prism is terminated by a four-sided pyramid, forming with the lateral
faces an angle of 130° 20'.

Two varieties of beaumontite are usually met with in mineralo-
gical collections ; one of these is of a fine honey-yellow colour, the
other of a pale yellow ; both of them are found in a quartzose rock

* There must be some error in the statement made as to its boiling
point, or as to that at which its density is taken. — Edit.

Intelligence and Miscellaneous Articles. 237

with haydenite, which constitutes a large portion of the rock, iron
pyrites, brilliant black rhombic crystals of carbonate of iron, some-
times with green hornblende or white stilbite, possessing the usual
form of the crystals of stilbite.

The density of beaumontite was found to be 2*24, which is very
near 2*25, that of epistilbite ; when heated in a glass tube it yields
water, becomes white, swells much, and becomes powdery; on
the platina wire it produces a white opalescent pearl ; with salt of
phosphorus it fuses readily into a glass, in which a skeleton of silica
floats, and which indicates a little iron ; with carbonate of soda lively
effervescence ensues, and the fusion becomes perfect.

Beaumontite resists the action of acids, which appears to be in-
consistent with its characters before the blowpipe, they being those
of the zeolites ; thus it is not acted upon by dilute nitric acid, and
it is with difficulty attacked either by hydrochloric or sulphuric acid
after calcination. When, however, it is reduced to a very fine
powder, and treated before calcination with concentrated hydro-
chloric acid, it is completely decomposed, and the silica is separated
in a granular state.

The qualitative examination proved that the mineral contains
water, silica, alumina, oxide of iron, lime, magnesia, and a little soda ;
sulphur, which might be suspected on account of the pyrites, was
sought for in vain.

The honey-yellow variety was selected for quantitative analysis ;
appeared to contain more lime than the greenish yellow, in which it
is replaced by magnesia ; as this mineral becomes perfectly white by
calcination, it is easy to remove by this operation any small portions
of foreign matter which may have escaped the first trial; the cal-
cined mineral was first subjected with carbonate of barytes to the
heat of a forge ; the silica was determined in the usual way, and dis-
solved totally in potash ; the alumina, precipitated by ammonia after
adding the hydrochlorate. was afterwards dissolved in j)otash ; the
portion of the precipitate which was insoluble was treated with di-
lute sulphuric acid ; the oxide of iron was precipitated by ammonia,
and the mother- water, containing a little magnesia, was set aside.
The lime was precipitated in the state of oxalate, and the sulphates
were converted into carbonates by means of the acetate of barytes ;
on treatment with water the magnesia remained, and by evaporation
traces of carbonate of soda were obtained. The insoluble portion,
containing the magnesia, was treated with dilute sulphuric acid, and
the solution added to the mother-water containing magnesia, the
total quantity of which was determined in the state of phosphate.
The results of the analysis wrere —

Silica 64-2

Alumina 14-1

Lime 4'8

Magnesia 1*7

Protoxide of iron. . 1'2

Water 13'4

Soda and loss .... '6

100-

238 Intelligence and Miscellaneous Articles.

It appears from this analysis that heaumontite should he classed
with the zeolites, and that it contains more silica than any one
hitherto descrihed ; it is undoubtedly to this circumstance that its re-
sistance to acids is owing, and also its hardness, which is nearly equal
to that of phosphate of lime. — Ann. de Ch. et de Phys., Decernbre
1843.

DESCRIPTION AND ANALYSIS OF SISMONDINE (a NEW MINERAL).
BY M. A. DELESSE.
This substance is found at St. Marcel, and the name was given to
it in honour of M. Sismonda, Professor in the University of Turin,
and author of the geological map of Piedmont.

Its characters are, that it is of a deep green colour, possessing
much splendour, it cleaves readily and reflects the light brilliantly ;
it is brittle and easily powdered, the colour of the powder is a bright
grayish green. It does not affect the magnet, either before or after
calcination. It scratches glass, but is scratched by steel ; its density
is 3*565 ; the crystalline form of this mineral could not be deter-
mined.

This mineral occurs imbedded in a kind of slaty chlorite, and is
accompanied with red dodecahedral garnets and titaniferous iron,
the fracture of which resembles plumbago, and the powder is per-
fectly black.

When heated in a glass tube sismondine yields water, but it re-
quires to be strongly heated to produce this effect ; the water is not
acid, nor does it act on the tube. Before the blowpipe it does not
fuse, but becomes of a varying tombac brown. It dissolves with the
salt of phosphorus, but with difficulty ; when it is powdered the so-
lution takes place totally and readily ; the pearl, which is coloured
when hot, becomes colourless on cooling.

With borax the reaction of iron is evident ; with soda there is
lively effervescence ; small white skeletons of silica float without
dissolving in the interior of the pearl, which when cold is not trans-
parent ; with nitrate of cobalt a dirty gray colour is produced ; when
very finely levigated sismondine is completely acted upon by sulphu-
ric, hydrochloric, and even by nitric acid, a white granular residue of
silica is left, which is not dissolved by the acids ; after calcination the
action of the acids is not so easy.
By analysis it yielded —

Silica 24-1

Alumina 43*2

Protoxide of iron. . 23*8

Water 7"6

Oxide of titanium trace
98-7
Ann. de Ch. et de Phys., Decernbre 1843.

A METEOROLOGICAL PHENOMENON.

About the middle of March 1843, an anthelion was observed on a
cloud in the vicinity of Cork by Mr. H. Hennessy.

Meteorological Observations. 239

Between four and five o'clock a.m., a faint image of the sun was
perceived on the perpendicular side of a mass of clouds, called in
Howard's nomenclature cumulo-stratus. These clouds were lying to
the east of the observer. As the sun approached the horizon this
image grew more distinct, and when the sun's altitude was about 1 5°
it reached its maximum of intensity. At this time rays of light were
reflected from the anthelion on surrounding objects. Its apparent
diameter seemed to be the same as that of the sun. At one period
of its existence it was surrounded by a faint fringe of prismatic co-
lours. The orange and red were more distinct than any of the other
colours. The gray colour of the cloud rendered it impossible to trace
the bluish tints of the fringe with any certainty. As the sun's alti-
tude became less than 15° the anthelion became less distinct, and
soon afterwards entirely vanished.
Prospect Row, Cork, Feb. 9, 1844. Henry Hennessy.

METEOROLOGICAL OBSERVATIONS FOR JANUARY 1844.

Chiswick. — January 1. Snow and sleet: clear and frosty at night. 2. Clear:
sharp frost at night. 3. Severe frost : overcast : thawing rapidly. 4. Hazy :
overcast. 5. Overcast : rain. 6. Mild and fine. 7. Exceedingly clear and fine :
frosty. 8. Frosty : fine. 9. Thick haze : cold and dry : overcast. 10. Hazy :
drizzly. 11. Overcast. 12. Foggy: heavy rain. 13. Slight drizzle : heavy
clouds: squally, with rain. 14. Hazy and drizzly : clouds in strata: densely
overcast. 15. Clear and frosty. 16. Sharp frost : very fine. 17,18. Overcast.
19. Fine: densely clouded. 20. Cloudy, cold and dry. 21. Overcast. 22. Hazy:
very fine. 23. Foggy : very fi ne. 24. Slight fog. 25. Frosty : very fine. 26.
Very fine. 27. Slight rain. 28. Rain : fine. 29. Clear: overcast: squally.

30. Fine: showery. 31. Brisk wind, with small hail: stormy showers, snow,
sleet, rain : densely overcast. — Mean temperature of the month 2^° above the
average.

Boston. — Jan. 1. Cloudy: rain early a.m. 2, 3. Fine. 4, 5. Cloudy: rain
early a.m. 6. Fine: rain early a.m. : rain p.m. 7. Cloudy. 8. Fine. 9. Cloudy:
snow p.m. 10. Fine : rain p.m. 11. Cloudy. 12. Fine : rain p.m. 13. Cloudy:
rain p.m. 14—16. Fine. 17. Cloudy. 18 — 20. Fine. 21. Cloudy: rain
early a.m. 22. Cloudy. 23. Cloudy : rain early a.m. 24, 25. Foggy. 26. Fine.
27. Cloudy. 28. Cloudy : rain early a.m. : rain p.m. 29. Fine. 3a Stormy.

31. Fine: stormy p.m.

Sandwich Mmme, Orkney. — Jan. 1. Snow-showers. 2. Snow: bright : cloudy.
3. Snow-showers : clear. 4. Bright : frost : clear. 5. Rain. 6. Bright : rain.

7. Damp : clear. 8. Bright : clear. 9. Cloudy : rain. 10. Showers. 11. Bright:
cloudy. 12. Rain ; showers. 13. Bright: cloudy. 14. Frost : snow : clear.
15. Cloudy. 16. Cloudy: drizzle. 17. Drizzle. 18. Showers. 19. Hail-
showers. 20. Snow-showers: cloudy. 21. Showers. 22. Bright: cloudy.
23. Drizzle. 24. Bright: fine. 25,26. Showers. 27. Bright: drizzle. 28.
Sleet-showers. 29. Rain: showers. 30. Sleet : showers. 31. Snow-drift : clear.

Applegarth Manse, Dumfries- shire. — Jan. 1. Frost: snow-shower. 2. Frost,
severe. 3. Thaw : rain p.m. 4. Small rain. 5, 6. Heavy rain. 7. Showers.

8. Frost. 9. Snow: rain p.m. 10. Frost. 11. Fog. 12. Small rain. 13. Frost:
fair and fine. 14, 15. Frost : fine. 16. Slight frost. 17. Frost : fine. 18. Frost.
19. Showery. 20. Frost, slight. 21. Fair and clear. 22. Frost: fine. 23.
Frost: mild. 24. Fair and mild. 25. Rain at noon. 26. Fair and fine. 27.
Fair, but cloudy. 28. Shower, heavy. 29. Wet. 30. Rain : snow-shower.
31. Frost and snow.

Mean temperature of the month 38°*4

Mean temperature of January 1843 ; 37 *8 —

Mean temperature for twenty years 34 '2

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LONDON, EDINBURGH and DUBLIN

PHILOSOPHICAL MAGAZINE

AND

JOURNAL OF SCIENCE.

[THIRD SERIES.]

APRIL 1844..

XXXVII. On the Manner in which Cotton unites with Co-
louring Matter. By Walter Crum, Esq., Vice-President
of the Philosophical Society of Glasgow*.

THE effect of porous bodies in producing combination and
decomposition, independently of chemical affinity, has of
late years occupied considerable attention.

If we examine, says Prof. Mitscherlich, a piece of box- wood
by the microscope, we find it composed of cells which have a
diameter of about 2T0 iTtn °f an mch. Heated to redness, the
form of these cells suffers no change, for the particles of which
it is composed have no tendency to run together in fusion. A
cubic inch of box-wood charcoal boiled for some time in water
absorbed five-eighths of its volume of that liquid ; from which,
and other data, it was computed that the surface of its pores
was 73 square feet.

Saussure observed that a cubic inch of box-wood charcoal
absorbed 35 cubic inches of carbonic acid ; and as the solid
part of the charcoal formed three-eighths of its bulk, these
35 inches of gas must ^ave been condensed into five-eighths
of an inch, or 56 cubic inches into one, under the ordinary
pressure of the atmosphere. But carbonic acid liquefies under
a pressure of 36-7 atmospheres, and therefore with a power
of condensation equal to 56 atmospheres, which the charcoal
exerted in Saussure's experiment, at least one-third of the gas
must have assumed the liquid state within its pores.

Every other porous body has the same property as charcoal.
Raw silk, linen, thread, the dried woods of hazel and mulberry,
though they condense but a small quantity of carbonic acid,
take up from 70 to 100 times their bulk of ammoniacal gas;

* Read before the Philosophical Society of Glasgow, February 1, 1843;
and communicated to this Journal by the Author.

Phil. Mag. S. 3. Vol. 24-. No. 1 59. April 1 844. R

242 Mr. W. Crum on the Manner

and Saxon hydrophane, which is nearly pure silica, absorbs
64 times its bulk. The gases enter into no combination with
the solid which absorbs them, for the air-pump alone destroys
their union.

The manner in which gases are attracted to the surfaces of
solid bodies is very much like that which these exert on sub-
stances dissolved in water. The charcoal of bones has been
long employed to remove colouring matter from the brown
solution of tartaric acid, from syrup in the refining of sugar,
and from a variety of other liquids containing organic sub-
stances ; and it is found that the colouring matter so attracted
remains attached to the surface of the charcoal without effect-
ing any change upon it. In this animal charcoal the carbon
is mixed with ten times its weight of phosphate of lime, and
if that be washed away by an acid, the remaining charcoal has
nearly twice the decolorating power of an equal weight of ivory-
black. Bussy, who has made the action of these charcoals the
subject of particular investigation, informs us that if ivory-
black, after the extraction of its earth of bones by an acid, be
calcined along with potash, and the potash be afterwards
washed out ; or if blood be at once calcined with carbonate of
potash and washed, the remaining charcoal has the power of
decolorating twenty times as much syrup as could be done by
the original bone charcoal. Animal charcoal removes also
lime from lime water, iodine from a solution of iodide of po-
tassium, and metallic oxides from their solutions in ammonia
and caustic potash.

A satisfactory explanation of these remarkable facts has yet
to be sought for. Mitscherlich calls the force which produces
them an action of contact, or attraction of surface ; and he
calculates, as we have seen, the extent of surface in propor-
tion to the mass as the measure of the force which it exerts.
On the other hand, Saussure, in his valuable paper on the
absorption of gases, informs us that charcoal from box- wood,
in the solid state, absorbs twice as much common air as when
it is reduced to powder. Now the effect of pulverization is
certainly not to diminish the extent of surface. Saussure ac-
counts for it in another way, and his explanation seems to
connect many of the facts. The condensation of gases in solid
charcoal goes on, he conceives, in the narrow cells of which it
is composed, and is analogous to the rise of liquids in capillary
tubes. In both, he says, the power appears to be in the in-
verse ratio of the size of the interior diameters of the pores or
tubes of the absorbing bodies. When we pulverize a body
containing such cells, we widen, open and destroy them. Fir
charcoal, whose cells are wide, absorbs 4^ times its bulk of

in which Cotton unites with Colouring Matter. 243

common air, and box-wood charcoal with smaller pores takes
7^. Charcoal from cork, with a specific gravity of only 0*1,
absorbs no appreciable quantity.

It appears to me that many of the operations of dyeing de-
pend upon this influence of the surface, or the capillary action
described by Saussure.

The microscopic examination of the fibres of cotton by Mr.
Thomson of Clitheroe, and Mr. Bauer, shows them to con-
sist of transparent glassy tubes, which when unripe are cylin-
drical, and in the mature state collapsed in the middle, from
end to end, giving the appearance of a separate tube on each
side of the flattened fibre.

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 would be in similar circumstances without the
intervention of cotton. During the decomposition of this 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 alumine 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 interior of the
tubes of which wools consist. 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 inclosed.

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 mi-
neral constituent being previously connected with the cotton.
The process of cleansing in boiling liquids and in the wash-
wheel, to which cotton printed with the various mordants is
subjected previous to being maddered, is to remove those por-
tions of metallic oxide which have been left outside the fibres
or got entangled between them, and fastened there more or less
firmly by the mucilage employed to thicken the solution.

The view I have now given is in some respects the old me-
chanical theory of dyeing held by Macquer, Hellot, and Le
Pileur d'Apligny, before the time of Bergman. Although

R2

241? Mr. W. Crum on the Manner

unacquainted with the microscopic appearance of cotton,
d'Apligny argued that as no vegetable substance in its growth
can receive a juice without vessels proper for its circulation,
so the fibres of cotton must be hollow within. And of wool,
he says, the sides of the tubes must be sieves throughout their
length, with an infinity of lateral pores. We may gather also
that he conceived dyeing to consist, first, in removing a me-
dullary substance contained in the pores of the wool, and af-
terwards depositing in them particles of a foreign colouring
matter.

But Bergman, in his Treatise on Indigo, in 1776 upset all
this, and attributed to cotton a power of elective attraction,
by which all the phaenomena of dyeing were referred to
purely chemical principles. Macquer soon adopted the che-
mical theory, and it was keenly advanced by Berthollet, who
succeeded Dufay, Hellot and Macquer in the administration
of the arts connected with chemistry. Berthollet has been
followed by all, so far as I know, who have since that time
written on the subject, but nothing like evidence has ever been
produced ; and if we only consider that chemical attraction
necessarily involves combination, atom to atom, and conse-
quently disorganization of all vegetable structure; that cotton
wool may be dyed without injury to its fibre, and that that fibre
remains entire when, by chemical means, its colour has again
been removed, we shall find that the union of cotton with its
colouring must be accounted for otherwise than by chemical
affinity. In particular processes, as we shall afterwards see,
attraction is no doubt exerted ; but it is an attraction con-
nected with structure, and therefore more mechanical than
chemical.

When we examine with a powerful microscope a fibre of
cotton, dyed either with indigo, with oxide of iron, chromate
of lead, or the common madder-red, the colour appears to be
spread so uniformly over the whole fibre that we cannot decide
whether the walls of the tube are dyed throughout, or that
the colouring matter only lines their internal surface. But
the microscope shows that the collapse which occurs in raw
and bleached cotton is very considerably diminished in the
dyed.

The greater number of specimens of Turkey-red which I
have examined show the same uniformity of colour, but in
others of them little oblong balls appear all along the inside of
the tube, of the fine pink shade of that dye, while the tube itself
is colourless. It is in stout cloth dyed in the piece that these
rounded masses occur, and the observation has been confirmed
by several of my friends who are practised in microscopic re-

in 'which Cotton unites with Colouring Matter. 24>5

search. But I shall resume these observations with a more
perfect instrument, which I hope soon to possess.

We have moreover the powerful analogy of the arrange-
ment of colouring matter in plants in support of this view of
the case. " Cellular tissue," says Dr. Lindley in his Introduc-
tion to Botany, "generally consists of little bladders or vesi-
cles of various figures adhering together in masses. It is trans-
parent, and in most cases colourless ; when it appears other-
wise its colour is caused by matter contained within it."

" The bladders of cellular tissue are destitute of all perfora-
tions, so far as we can see, although, as they have the power
of filtering liquids with rapidity, it is certain that they must
abound in invisible pores." " The brilliant colours of vege-
table matters, the white, blue, yellow^ scarlet, and other hues
of the corolla, and the green of the bark and leaves, is not
owing to any difference in the colour of the cells, but to the
colouring matter of different kinds which they contain. In
the stem of the garden balsam a single cell is frequently red
in the midst of others which are colourless. Examine the red
bladder, and you will find it filled with a colouring matter of
which the rest are destitute. The bright satiny appearance
of many richly-coloured flowers depends upon the colourless
quality of the tissue. Thus in Thysanotus fascicularis, the
flowers of which are of a deep brilliant violet, with a remark-
ably satiny lustre, that appearance will be found to arise from
each particular cell containing a single drop of coloured fluid,
which gleams through the white shining membrane of the
tissue and produces the flickering lustre that is perceived."
Cotton is itself cellular tissue, and the ligneous basis of all the
forms of these vessels has the same chemical constitution.

I have alluded to another class of processes in dyeing in
which the action much more resembles chemical affinity. I
mean that in which pure cotton by mere immersion in different
liquids withdraws a variety of substances from their solution.
The " indigo vat" is a transparent solution, of a brownish yel-
low colour, consisting of deoxidized indigo combined with lime,
and containing seldom more than y^th of its weight of co-
louring matter. By merely dipping cotton in this liquid the
indigo attaches itself to it in the yellow state, in quantity pro-
portioned within certain limits to the length of the immer-
sion ; and all that is necessary then to render it blue is to ex-
pose it to the air. Here an inactive spongy substance exer-
cises a power which overcomes chemical affinity, but the mix-
ture, which is formed of cotton and indigo, possesses none of
the characters of a chemical compound. We can only recog-
nise in this action the same force, whatever that may be, which

246 The Rev. A. Sedgwick's Outline of

enables animal charcoal to decolorate similar liquids. Char-
coal, as we have also seen, withdraws metallic oxides from
their solution in alkalies. Cotton wool has the same power,
and it is extensively used as a means of dyeing with the yellow
and red chromates of lead. If lime in excess be added to
sugar of lead dissolved in a considerable quantity of water,
the lead, which precipitates is redissolved in the lime water
and forms a weak solution of plumbate of lime. If a piece of
cotton be immersed in this solution it appropriates the lead,
and when afterwards washed and dipped in a solution of
chrome, the lead becomes chromate of lead.

The same force enables cotton to imbibe basic salts of iron
and tin by immersion in certain solutions of these metals; and
many other examples of what Berzelius calls a catalytic force,
in decomposing weak combinations, will occur to those who
are familiar with the art of dyeing.

It appeared to me interesting to compare the amount of sur-
face exposed by cotton wool with that of the more minute di-
visions of charcoal. I am enabled to furnish the following
calculation through the kindness of Professor Balfour, who
has measured with great care the fibres of various qualities of
wool. The fibre of New Orleans wool varies most commonly
from ijootn to 2oVotn 0,? an *ncn ni diameter. About forty
of these fibres or tubes compose a thread of No. 38 yarn
(thirty-eight hanks to the pound). Ordinary printing cloth
has, in the bleached state, 493 lineal feet of fibre, or 10*6 square
inches of external surface of fibre in a square inch, which
weighs nearly one grain. It is easy to compress 210 folds of
this cloth into the thickness of one inch. It has then a spe-
cific gravity of 0'8. One cubic inch has 94*163 lineal feet of
tube, and 16'8 feet of external surface; or, if we include the
internal surface, there are upwards of 30 square feet of surface
of fibre in one cubic inch of compressed calico. The char-
coal of box-wood has, as we have seen, 73 square feet of sur-
face to the inch, with a specific gravity of 0*6*.

XXXVIII. Outline of the Geological Structure of North

Wales. By the Rev. A. Sedgwick, F.G.S.f

§ 1. Introduction.

rr*HE author here describes in considerable detail the geographical

-■• limits of the country under notice. For the structure of the Isle

of Anglesea he refers to a paper by Prof. Henslow, published in the

* For drawings of cotton and linen see Phil. Mag., Nov. 1834. (S. 3. vol.
v.p. 355.)

•j- From the Proceedings of the Geological Society, vol. iv. p. 212, having
been read June 21, 1843.

the Geological Structure of North Wales. 247

Cambridge Transactions. The carboniferous series of Denbighshire
and Flintshire is passed over with a slight notice, and without any-
detailed sections. His chief details are confined to the counties of
Denbigh, Carnarvon, Merioneth, and Montgomery ; and the southern
limit of his survey is denned by an irregular line drawn from the
Severn, near Welch Pool, to the coast near Aberystwith. The
southern boundary is purely arbitrary, marking only the limits of his
survey, and not any physical separation of the older rocks, which
are continued in great undulations through all the higher parts of
North and South Wales. He then describes the several connected
traverses by which he was led to the general views now laid before
the Society; and to the modifications his views have undergone
in consequence of traverses made by him in 1834 and 1842 along
the line of the Holyhead road, and from that line to the mountain
limestone ridges of Denbighshire and Flintshire.

As a general conclusion from these details, he states that the older
stratified rocks (including all the formations of the region inferior
to the mountain limestone) may be separated into three great phy-
sical groups or primary divisions.

(1.) Chlorite and mica slate, &c, occupying the south-west coast
of Carnarvonshire, and a considerable portion of the Isle of Anglesea.

(2.) Greywacke, roofing-slate, &c. (alternating with masses and
beds of contemporaneous plutonic rocks), spread out from the Me-
nai to the edge of Shropshire, occupying all the high ridges of Car-
narvonshire and Merionethshire ; to the south blending themselves
with the system of South Wales ; and to the north nearly bounded
by the line of the great Holyhead road.

(3.) A great overlying (and sometimes unconformable) deposit of
flagstone, slate, &c. (Upper Silurian), extending through the hills
north of the Holyhead road, and overlaid by the mountain limestone.

These three primary divisions the author represents by three co-
lours on a geological map ; and the same system of colouring may
be extended through all the older formations of South Wales. The
middle group is however of enormous thickness, and may hereafter
be further subdivided. Its lower part contains no fossils, and in its
upper part they abound ; but between its upper and lower parts
there is no true physical separation, and the fossils seem gradually
to disappear in the descending sections. He could indeed represent
the fossiliferous and non-fossiliferous slates of Carnarvonshire by two
colours ; but in extending these colours through other counties of
North Wales, he would be compelled, in the present state of his in-
formation, to adopt arbitrary, and perhaps inconsistent, lines of de-
marcation. Hence he has been induced, for the present, to adopt
a more simple system of colouring than he at first attempted.

§ 2. Physical structure of the country under notice. — Strike and undu-
lations of the strata. — Structure and relations of the three great divi-
sions, 8(C
South Carnarvonshire. — Carnarvonshire is divided into two physical

regions, — one to the south-west and the other to the north-east of

248 The Rev. A. Sedgwick's Outline of

the road from Carnarvon through Llanllyfni to Tremadoc. In the
south-western country, the coast, from Porthdinlleyn to the end
of the great promontory, and to Bardsea Island, is composed of chlo-
rite and mica slate. It forms a band on the average not two miles
in breadth, but it is evidently the prolongation of a formation which
is widely expanded in the Isle of Anglesea. At its north end it is
associated with a mass of brecciated serpentine (like that subordi-
nate to the same rocks in Anglesea), and it is here and there pene-
trated by veins of calcareous spar, sometimes so abundant as to re-
place the ordinary rock, which in such cases passes into great irre-
gular masses of white crystalline limestone. Near its north end it
is cut through by five or six nearly transverse vertical dykes of au-
gitic trap of a later formation.

The other parts of the promontory are composed of greywacke,
(sometimes passing into a coarse arenaceous rock), and greywacke
slate, often of a dark colour and rather earthy structure ; and these
rocks are pierced and broken through by many great bosses of sye-
nite (represented on a geological map), which rise into hills of re-
markable and irregular outline. That the syenites are posterior to
the slates the author shows by the evidence of sections : but the
slates are little altered, except near the places of contact. Their
prevailing strike is nearly parallel to the mean direction of the pro-
montory (about north-east). Near the bosses of syenite these beds
are sometimes almost vertical, and they contain one or two bands of
organic remains, the most remarkable of which are found in a ver-
tical ridge of coarse greywacke near Bodean*.

In the promontory near St. Tudwal's Island the rocks are thrown
into low undulations, are traversed by mineral veins, and intersected
by one or two trap dykes.

The author here notices five or six dykes of augitic trap which
cross to the west side of the Menai near Bangor. They appear like
great ribs locking together the mineral systems of Anglesea and
Carnarvonshire. Similar dykes appear in three or four places in the
higher parts of the Carnarvon chain ; and all dykes of augitic trap
above noticed are considered of nearly the same epoch, and of a later
date than the mountain limestone and new red sandstone of the
Menai Straits.

Near the line of road above mentioned the country is at a low
level, and much concealed by drifted matter ; it is however marked
here and there by erupted masses of felstone porphyry, which in one
or two places are finely columnarf. Near this line are some enor-
mous faults which have thrown the south end of the Carnarvon chain
about 2000 feet above the level of the road. Near Tremadoc the
continuation of the same lines of fault have torn mountain masses

* Among these fossils are, — 1. many encrinital stems; 2. Entomostraciics
punctatus; 3. Lcptcena sericea ; 4. Or this Flabellulum, O.pecten, 0. canalis,
O. testudinaria, &c.

•f* By the word felstone the author defines many rocks commonly called
compact felspar ; an incongruous name he wishes to replace by a name
(Feldstein) occasionally used in Germany.

the Geological Structure of North Wales. 249

of rock from the end of the chain, and placed their beds nearly at
right angles to the beds of the great chain. The enormous disloca-
tions are traced through Merionethshire beyond the mouth of the
Barmouth estuary, but their description could not be understood
without the help of sections.

North part of Carnarvonshire and Merionethshire, as far east as the
line of the Bala limestone, $c.

On the north side of the country last mentioned commences the
great Carnarvon chain, prolonged, in fine serrated ridges, to the
neighbourhood of Great Ormeshead. In the low countiy east of
the Menai are slate rocks alternating with trappean conglomerates,
and with great masses of porphyry ranging very nearly with the beds
of slate. One of the larger masses of porphyry appears to have
been protruded after the deposition of the slates : other masses are
contemporaneous with the slates. To the east of the largest elon-
gated mass of porphyry, which strikes with the beds for about fif-
teen miles, commences a system of undulations affecting the whole
chain, the anticlinal and synclinal lines ranging very exactly with
the strike of the beds, i. e. N.N.E. or N.E. by N. The same pre-
vailing strike and the same undulations are continued into Merio-
nethshire ; but in the southern parts of that county the strike de-
viates to the north-east and south-west. One great anticlinal line
is traced from the country about three miles east of Festiniog to a
point on the coast a little south of Barmouth. Beyond this line is
an ascending section (very little interrupted by undulations), as far
as the Bala limestone. These facts are described by the author in
detail, and are illustrated by parallel sections at right angles to the
mean strike of the country.

The rocks occupying the region are chiefly composed of felstone,
(compact felspar) and felstone porphyry, trappean conglomerates,
plutonic silt (exactly like chloritic varieties of German Schaalstein),
and other erupted or recomposed igneous products : and the above-
named rocks alternate indefinitely with fine masses of roofing-slate,
and with great masses of greywacke ; and with greywacke slate,
often calcareous, but rarely containing beds and masses of limestone.
Three or four subordinate masses of such limestone are found near
Great Arenig, and one or two on the flanks of Cader Idris. The
author describes some sections where the igneous rocks predominate
over the aqueous ; others in which the aqueous almost exclude the
igneous : but the two classes of rock are so interlaced that they
cannot be separated, and are regarded as of contemporaneous origin.
Among them are however masses of greenstone (sometimes syenitic,
and more rarely basaltic), and other trappean masses among the
slates which are considered of a later date.

Nearly all the slate rocks are affected by a cleavage, which often
obliterates all traces of stratification, and very seldom coincides with
the true beds. In the fine quarries of Nant Francon and Llanberris,
the cleavage planes (as in the great quarries of Cumberland) strike
exactly with the beds, but are inclined at a greater angle. The
strike and inclination of these planes is not however governed by

250 The Rev. A. Sedgwick's Outline of

any fixed law ; for cases are pointed out where cleavage planes are
much less inclined than the beds, and others in which these planes,
even in fine quarries, deviate one or two points from the strike of
the true beds. Five cases are exhibited in the sections where the
cleavage planes continue their strike and dip through all the con-
tortions of the beds ; and a few cases are given of a good second
cleavage plane. From all the facts the author concludes that clea-
vage planes are true crystalline phenomena, produced by the mutual
action of the elementary particles of the rock while passing into a
solid state.

Jointed structure is also discussed at some length : and joints are
divided into four classes, called dip, strike, diagonal, and tabular joints.
The two former are most constant, often highly inclined, and divide
the slaty beds into great rhombohedral masses. They are supposed
to have been formed by mechanical tension while the rocks passed
into a solid state. Cleavage planes are not parallel to them ; and they
cannot arise from molecular or true crystalline action ; because, as
shown from examples in North Wales, they cut through the pebbles
of beds of conglomerate : sometimes however, among the accidents
of structure, true cleavage planes and joints become confounded.

Bala limestone. — System of the Berwyns. — Fossiliferous beds on the
line of the Holyhead road, #c.

This limestone ranges through Cader Dinmael to Glyn Diffwys on
the Holyhead road, a few miles east of Corwen. Thence it is pro-
longed towards the south ; but its continuity is broken, and for some
miles its range has not yet been made out. Exactly on the line of strike
(N.N.E. and S.S.W.) it breaks out again near Bala, and ranges
thence to the neighbourhood of Dinas Mawddwy, dipping steadily
to the E.S.E.

From this limestone there is an ascending section to the very crest
of the Berwyn chain, south of the road from Bala to Llangynog.
In this ascending section are higher calcareous slates, which in one
or two places have been burnt for lime. But on the east flank of this
part of the chain there is a synclinal line, beyond which for several
miles the beds dip to the N.W. ; and a series of slate rocks, alternating
with a few bands of porphyry, are again brought up to the surface.
Some of these are only a repetition of a portion of the slates and
porphyries on the east side of the range of the Bala limestone. These
older rocks abut against, and, in consequence of enormous convul-
sions, in one or two places seem to overlie the Silurian rocks (among
the tributaries of the Severn) described by Mr. Murchison.

The synclinal line above noticed appears to strike about N.N.E. ;
but the mean direction of the water-shed of the Berwyns is about
N.E. : hence the synclinal line, and the calcareous slates overlying
the Bala limestone, are, near the Llangynog road, brought to the west
side of the chain ; and the crest of the ridge, extending beyond Ca-
der Ferwyn, is composed of the older slates and porphyries dipping
towards the N.W. Still further north, either from a great flexure
or (more probably) from an enormous fault, we have for several
miles a great series of beds dipping to a point a few degrees east of

the Geological Structure of North Wales. 251

north. They alternate here and there with porphyry, contain many
fossils, and in their highest portion near Llansaintfraid Glyn Ceiriog,
contain two bands of limestone. At this place they seem to form a
regular ascending section, conducting without a break to the over-
lying Upper Silurian flagstone.

The author then notices the undulating country east of the Ber-
wyns, extendingfrom the Severn, near Pool, through the ramifications
of the Vyrnwy and the Tanat. Calcareous slates, with many fossils
nearly resembling those of the Bala limestone, are repeated again
and again by rapid undulations : the facts are illustrated by sections.

The beds have a prevailing strike about N.E. ; but it is frequently
interrupted, and they are twisted out of their course so as in some
tracts to strike east and west ; and in other places the strikes and dips
are entirely anomalous. The whole system in some places seems to
dip under the older rocks of the Berwyns, in others it is placed side
by side with them, the junction planes being vertical ; and again the
same system is seen to be thrown off with an eastern dip from the
flank of the older chain. Everything indicates great derangement, of
a later date than those which gave the impress to the Carnarvon chain,
and probably contemporaneous with the movements which placed
the beds of the north end of the Berwyns in the anomalous position
above described. Part of the system here noticed has been described
by Mr. Murchison, and is classed in the Caradoc sandstone.

Lastly, the author notices a comparatively low country near the
line of the Holyhead road, extending westward to the neighbourhood
of Bettws y Coed, in which the strike of the Carnarvon chain(N.N.E.)
is but feebly impressed. The beds undulate, and are sometimes
almost horizontal ; but here and there they are thrown into ridgesjwith
the N.N.E. strike ; and in all these different positions they are over-
laid by the Upper Silurian ridges. These beds are at the northern limit
of the Merioneth and Carnarvon ridges, are high in the ascending sec-
tions, and near Penmachno, Bettws y Coed, &c, contain many fossils.

Upper division of the slate rocks. — Denbigh flagstone, &c.
The author traces in detail the line of demarcation between the
rocks of this and of the preceding division. From Conway to a
point a few miles south of Llanrwst, this demarcation is represented
by a great fault ; afterwards by an irregular line (traced on a map),
partly south and partly north of the great Holyhead road. A few
miles below Corwen it crosses the valley of the Dee, passes over the
crest of the hills, and strikes down the valley of the Ceiriog, in the
lower part of which it is cut off by the mountain limestone. The
strike of this upper group is affected by great breaks and undulations,
but on the whole is about west by north, and east by south ; and
its prevailing dip is towards the north. Its structure is explained in
detail, and illustrated by three sections : the first (commencing with
the slates, porphyries and calcareous slate of the older division, south
of Llansaintfraid Glyn Ceiriog) passes through a peculiar mass of
dark roofing-slate, and is thence continued through Llangollen and
Dinas Bran to the terrace of mountain limestone. The second,
commencing a few miles to the west of the former, crosses the upper

252 The Rev. A. Sedgwick's Outline of

o

groups of flagstone, which are contorted, and in some places nearly
vertical; and it is prolonged to the tabular hills of the Denbigh
flagstone, south-west of Ruthin. The third (commencing with ridges
of sandstone and conglomerate at Gam Brys near Pen Tre Voelas)
is carried over the whole group, nearly north and south, to the es-
carpment of the mountain limestone near Abergele.

The first two sections give the following ascending series : —

1. Hard quartzose slates alternating with greywacke and beds of
porphyry : it is fossiliferous and of great thickness.

2. A great mass of calcareous slates with two subordinate beds of
limestone and with many fossils.

3. Dark roofing-slate with a few Graptolites.

4. A great thickness of Denbigh flagstone, &c, extending to the
mountain limestone. This is separated into three subdivisions : — (a.)
Lower flagstone series passing into hard quartzose bands and into
earthy semi-indurated shales. It has impressions of Orthoceratites,
and numerous compressed traces of fossils mistaken for Orthoceratites,
but considered by Mr. Forbes as a species of Pteropoda (Criseis).
Some of its beds exhibit many impressions of Graptolites Ludensis.
(b.) Beds resembling the former, but more indurated, also contain
here and there many fossils, among which Cardiola interrupta and
Terebratula Wilsoni are enumerated, (e.) Softer beds, more or less
slaty, with few fossils, surrounded by harder and more quartzose
bands with very numerous fossils (e. g. the summit of Dinas Bran).

In the preceding section Nos.l and 2 belong to the older division ;
No. 3 is considered doubtful ; but the whole of No. 4 is unequivo-
cally Upper Silurian.

The third section gives the following ascending series : —

1. Ridges of old rock with Caradoc sandstone fossils.

2. Great masses and beds of conglomerate and coarse sandstone
unconformable to the preceding. The conglomerates disappear in
the ascending section, and the coarse sandstones pass into a finer
structure, and alternate with bands of dark coarse slate, here and
there with a true cleavage. Among these beds are a few Upper Si-
lurian fossils.

3. A great thickness of Denbigh flagstone, generally agreeing
with No. 4 of the preceding sections.

4. Great ridges of roofing-slate alternating with thick beds of
coarse greywacke. The group is contorted and traversed with a few
mineral veins, which are worked near Bronhaulog. These beds
contain fossils described in a memoir by Mr. Bowman (see the Pro-
ceedings of the Geological Society, vol. ii. p. 667*).

5. A thick mass containing beds like those of the lower groups,
but often passing into a rotten slate or mudstone.

6. Mountain limestone.

This last group (No. 5) is overlaid further to the west by red
conglomerates described by Mr. Bowman. R.ed sandstones and
conglomerates also appear under the mountain limestone near Ru-
thin, which the author refers to the old red sandstone.

He concludes that the groups of this upper division cannot be
* Or Phil. Mag. S. 3. vol. xiii. p. 225.— Edit.

the Geological Structure of North Wales. 253

brought into any close comparison with the well-defined Upper Si-
lurian groups of Mr. Murchison ; neither do they closely resemble
hi mineral structure the Upper Silurian groups of Westmoreland :
but he compares the Denbigh flagstone with the fossiliferous slates
and flagstones of Horton and Settle in Yorkshire.

§ 3. Classification of the three preceding divisions of the Welsh slates. —
Organic remains, fyc.

The group of chlorite, slate, &c. contains no organic remains,
and forms no passage into the rocks of the other division ; it there-
fore offers no sure means of classification ; but it seems to be infe-
rior to the other slate rocks in the southern promontory of Car-
narvonshire.

The age of the middle division is decided by the organic remains.
None have yet been discovered in the low country east of the Menai,
but it is much concealed by alluvial drift.

Commencing with the line of the Nant Francon and Llanberris
slate quarries, the author describes a series of regular ascending sec-
tions, continued through a horizontal distance of three miles, and
intersecting beds without a single flexure, inclined more than 50°.
In this great mass of strata are no described fossils. But at its top,
fossil bands appear containing Orthis flabellulum and canalis in abun-
dance ; together with corals (Turbinolopsis ?) and stems of Encrinites.
These bands are traced on the east side of the highest summits of
the chain from Moel Hebog to Carnedd Llewelyn. All the country
east of that range might be represented by a peculiar colour ; but
it is in physical structure identical with the eastern parts of the
chain ; and the author wishes not to separate it on supposed nega-
tive evidence, which may be upset by new observations.

After two rapid undulations, there is again a regular ascending
section to Capel Curig ; and thence over the shoulder of Moel Shabod
to the bottom of the valley near Dolwyddelan. The ascending sec-
tion (interrupted only by one very short undulation), measured on a
horizontal base at right angles to the strike, is more than five miles
long, and is through highly inclined beds. The thickness of this
fossiliferous system must therefore be very great. But in the hills
east of Penmachno, and south of Bettws y Coed, are calcareous
beds (with more numerous fossils), which are placed in a still higher
part of the ascending section. These calcareous beds (sometimes
burnt for lime) the author places nearly on the parallel of the Bala
limestone ; though on general analogy, and not on any direct evi-
dence of sections.

Again, from the great Merioneth anticlinal (above described) to
the Bala limestone, there is a great ascending section ; on two or
three parts of which are found organic remains, far below the parallel
of the limestone. And above the Bala limestone, to the crest of the
southern Berwyns, is a series of beds, some of which contain many
Lower Silurian fossils, and at least one more calcareous band.

Lastly, the fossiliferous groups south of Llansaintfraid Glyn Cei-
riog, are (at least provisionally) brought into comparison with the
Bala limestone and other fossiliferous beds in the trough of the
southern Berwyns.

254 The Rev. A. Sedgwick's Outline of

The author then gives the subjoined lists of fossils from different
localities on the lines of the sections above noticed. It is a mere
synopsis of the fossil evidence, but has been carefully made out by
Mr. J. Sowerby ; and by Mr. J. W. Salter, who accompanied the
author in his last examination of the country along the line of the
Holyhead road.

List of Fossils from several localities in tlte middle division of the
Cambrian Slates.

I.

Penmachno and Conway

Falls.
Trinucleus Caractaci.
Asaphus Tyrannus.
Leptsena sericea.
Orthis canalis.

testudinaria.

— — alternata.

Actonise.

Tentaculites scalaris.

II.

Hills opposite Bettws-y-
coecl.

Crustacea.
Trinucleus Caractaci.

Heteropoda.
Bellerophon bilobatus.

Brachiopoda.
Leptsena sericea.
Orthis canalis.

testudinaria.

— — alternata.

Actonise.

flabellulum.

new (very convex)

(half a mile above Con-
way Falls).

III.

Cerrig y Druidion.
Orthis alternata.

new (abundant).

Ophiura Salteri.

IV.

Glyn Diffwys and Cader
Dinmael Limestone.

Crustacea.
Tails of a Calymene.
Asaphus Powisii.
■ Tyrannus.
Trinucleus Caractaci.
Brachiopoda.
Leptsena tenuistriata.
sericea (abundant).

Spirifer crucialis (new).

Orthis Actonise (do).

Vespertilio (do).

— — virgata (abundant).

— — canalis.

Radiata.

Favosites polymorpha.

Round coral.

Hemispherical coral
(new ?), and several
other species of corals
and shells.

V.

Sandstone bed on Cader
Dinmael {scarcely ex-
amined).

Crustacea.

Brachiopoda.
Orthis flabellulum (abun-
dant).
— — canalis.

CONCHIFERA.

Avicula, n.s.
VI.
Bala Limestone.

Crustacea.
Tails of a Calymene.
Brachiopoda.
Leptsena tenuistriata(none

of sericea).
Spirifer crucialis.
Orthis Actonise (do.).

Vespertilio (do.).

canalis.

virgata (abundant).

Radiata.
Round coral.
Hemispherical coral.
Tentaculites annulatus.

VII.

Calcareous Slates of Bala,
Gelli Grin, §c.

Crustacea.
Trinucleus Caractaci.

The fossiliferous series above described is called the great proto-
zoic group of North Wales. It is stated, that there is no good fossil
evidence for its separation into distinct formations ; and that its in-
ferior beds, although far below the Caradoc sandstone, contain com-

Brachiopoda.

Leptsena tenuistriata.

sericea (very large).

Spirifer radiatus, M. C.

crucialis?

Orthis flabellulum.

Vespertilio.

canalis.

alternata.

— — virgata.

MOLLUSCA.

Turbo Pryceae.

• angulatus 1

Euomphalus sculptus 1

Radiata.
Ophiura Salteri (pelvis).

VIII.

Slates. South of Llansaint-
fraid Glyn Ceiriog.
Crustacea.
Trinucleus Caractaci.
Calymene (tail).
Asaphus caudatus ?

Powisii.

Brachiopoda.
Leptsena tenuistriata.

sericea.

Orthis inflata (new).

canalis.

alternata.

Actonise.

Radiata.

Turbinolopsis bina
(abundant).

IX.

LlansalntfraidLime.ston.es

and Shales.
Leptsena sericea.
Orthis canalis.

Actonise.

Euomphalus (new).

Radiata.
Catenipora escharoides
(abundant), and many
others.

the Geological Structure of North Wales. 155

paratively few species undescribed in the work of Mr. Murchison.
It is therefore neither Silurian nor Cambrian in the limited sense in
which the words were first used ; but it represents both systems,
inseparable, as they are in nature, from one another.

The upper division of the Cambrian slate series is so obviously
Upper Silurian, that the author adds very few details in illustration
of those given in the previous parts of the paper. He however sub-
joins the following list of fossils, chiefly derived from the beds of the
third section from Gam Brys to Abergele through this division.

1 . In the highest beds near the north end of the section, — Encri-
nites, Graptolites Ludensis, Orthoceras virgatum, Leptcena lata, L.
depressa, Terebratula lacunosa, Orthis orbicularis, fyc.

2. South of Bettws Abergele, and rather lower in the series,—
Asaphus caudatus, Orthis orbicularis, Leptcena lata, Terebratula lacu-
nosa, Atrypa affinis, Cardiola interrupta, fye.

3 . In the valley of Llanfair Talhaiarn and Bronhaulog mines, —
Encrinites and branching corals, Bellerophon trilobatus, Leptcena lata,
Spirifer ptychodes, Orthis orbicularis, Atrypa affinis, Turbo corallii, #c,

4. Plas Madoc quarry near Llanrwst, under the great mass of the
Denbigh flagstone, and therefore low in the descending section.

Corals: — Fenestella, #<?., Calymene Blumenbachii*, Asaphus sub-
caudatus, Bellerophon globatus •, Leptcena euglypha, L. lata, Atrypa affinis,
Spirifer ptychodes, Orthis orbicularis, 0. lunata, Terebratula navicula,
T. lacunosa, fyc.

5. To these lists the author adds the following from Dinas Bran
near Llangollen, the upper part of the Denbigh flags.

Calymene (?) (in small fragments), Lituiti (in fragments), Ortho-
ceras striatum, O. ibex, 0. Ludense, Bellerophon expansus, Terebratula
navicula and lacunosa (in great abundance), Orthis lunata, Nucula
ovalis, Cypricardia retusa, Cardiola interrupta (?), Turbo carinatus, &;c.

The Denbigh flags contain impressions of Orthoceratites ; but
some which have been referred to that genus are considered by Mr.
Forbes as species of Criseis, a genus of Pteropoda. They occur in
the middle of the group associated with Graptolites Ludensis, and
sometimes with Leptcena lata, Cardiola, and other fossils.

From these lists it appears that the fossils of the upper division of
the great Welsh series agree very closely with the fossils figured by
Mr. Murchison, from the Wenlock shale to the tilestone at the base of
the old red sandstone inclusive. But the mineral structure of the
rocks being almost entirely different from that of the upper system
of Siluria, the distribution of the species is also different ; so that
they are incapable of being arranged into distinct groups marking
the successive parts of an ascending or descending section, so as to
agree with the subdivisions of Mr. Murchison. The author confirms
this remark by stating, that he now possesses more than ninety

* We see no reason for abrogating the very convenient rule which has
always prevailed since the establishment of the Linnaean terminology, of di-
stinguishing such specific names as are substantives by a capital letter. We
do not therefore adopt the mode of printing Calymene blumenbachii, or
Orthis vespertilio ; but shall continue to follow the universal practice of
naturalists in all countries. — Edit.

256 The Rev. A. Sedgwick's Outline of

species of the Upper Silurian fossils of Westmoreland, that nine-
tenths of them agree specifically with those described in the ' Silu-
rian System,' and that their arrangement in the actual sections ad-
mits of no rigid comparison with the subordinate groups of the system.

§ 4. Other formations over the preceding. — Successive dislocations
of the Welsh system, $c.

After briefly noticing one or two masses of red sandstone and
conglomerate (referred to the old red sandstone), the author de-
scribes the extraordinary position of the mountain limestone in the
Vale of Clwyd, and infers that it underwent its greatest dislocation
before the period of the new red sandstone, which is found appa-
rently in a great bay of the dislocated limestone. He then gives, in
the following order, a synopsis of the principal movements which have
affected the different formations within the limits described in the
paper.

1 . The oldest movements of which we have any distinct trace,
were those which gave the north-eastern strike and threw the moun-
tain masses into undulations.

The highest points of the Carnarvon chain (measured along the
strike from Conway) are upon an arch, the crown of which is the top
of Snowdon ; and the south end of the arch is broken off by the
Tremadoc fault. At what time this position was effected does not
appear ; but the tension by which it was produced broke the back of
the chain in three places, producing the rudiments of the three great
passes across the Carnarvon chain.

2. Afterwards, a series of movements gave the W.N.W. impress
both to the older system at the north end of the Berwyns, and to
the upper system in Denbighshire. The author considers that the
extraordinary confusion in the position of the beds in some parts of
the Berwyn chain is caused by the intersection of the two lines
of principal elevation, viz. the old movement to the N.E. or N.N.E.,
and the subsequent movement to the W.N.W. Probably after this
period were formed the conglomerates at the base of the mountain
limestone of Denbighshire.

3. At a later period was formed the great trough of the Vale of
Clwyd. About the same time (and probably before the period of
the new red sandstone) was formed a line of great dislocation,
marked by a patch of mountain limestone near Corwen, affecting
the dips of all the intermediate country as far as the great mineral
veins of Minera ; and lastly, bringing up a great mass of mountain
limestone near Caergwrle in Flintshire.

4. The great break of the Menai Straits appears to have taken
place after the new red sandstone : and probably about the same
time was formed the fault, ranging up the lower part of the Conway.

5. Lastly, all the external inequalities of the country must have
been altered, again and again, since the successive periods of im-
press, produced by the above lines of great movement. The whole
country has, at very recent geological periods, undergone great
changes of level. And the author confidently affirms, that the
mountain streams of North Wales, as far as he has examined them,

the Geological Structure of North Wales. 257

have been flowing in their existing channels, and producing the effects
of diurnal erosion (marked by deltas gradually filling up lakes, and
by other alluvial accumulations) only during a few thousand years.
He accepts the evidence of comparatively recent glacial action in
the higher valleys of North Wales (e. g. near Llyn Ogwen, &c),
but enters on no details.

§ 5. General conclusion.
From a review of the facts stated in this paper, combined with
the facts stated in a former communication (Nov. 1841*), the au-
thor suggests the following classification of the British Palaeozoic
rocks. They are considered zoologically as forming one great sys-
tem separable into four primary divisions, as follows : —
1. Carboniferous, subdivided into four principal groups.
(«). Magnesian limestone and lower red sandstone, zechstein and
rothe-todte-liegende. In this group are the drifted coal plants of
the lower red sandstone of England, and the coal-beds of the
Hartz, associated with the rothe-todte-liegende.
(b). Great coal formations of England, Scotland, Belgium, "West-
phalia, &c, freshwater beds, and many beds of plants not far
drifted ; sometimes unmoved from the spots where they grew.
(c). Millstone grit and shale, limestone, &c, with drifted plants
and beds of coal ; great scar limestone ; culm-measures of
Devon (?) ; great coal-fields in the West of Ireland,
(rf). Lower limestone and limestone shale, &c. ; imperfectly re-
presented in England, but probably here and there replaced by
the conglomerates at the top of the old red sandstone ; lower
limestone and carboniferous slates of Ireland ; lower coal for-
mations of Scotland. In this group are placed a part of the beds
of North Devon under the culm- measures, and containing fossils
like those of the carboniferous slates of Ireland.
2nd Division. — Devonian and old red sandstone. In this division
are placed the older fossiliferous slates, &c. of Devon and Corn-
wall ; the beds below the carboniferous limestone of Belgium and
Westphalia, as far as the Eifel and great Westphalian limestones in-
clusive ; all the old red fish-beds, &c. of Scotland ; all the central
part of the old red sandstone series of Herefordshire ; old red sand-
stone, &c. of Ireland.

3rd Division. — All the Upper Silurian rocks of Mr. Murchison,
from the Wenlock slates to the lower part of the " tilestone" inclu-
sive ; Denbigh flagstone ; upper division of the fossiliferous slates of
Westmoreland and Lancashire ; many portions of the fossiliferous
rocks of the Flemish provinces, and various parts of France ; some
small fossiliferous groups in the south of Scotland (?) ; a part of
the fossiliferous series in the north and south of Ireland (?).

4th Division. — Great protozoic group ; all the older fossiliferous
slates of North and South Wales ; Coniston limestone ; lower part of
the " Silurian system" of Mr. Murchison; oldest fossiliferous slates
of Scotland and Ireland, and of various parts of the continent, &c.

* Or Phil. Mag. S. 3. vol. xxi. p. 141.
Phil. Mag. S. 3. Vol. 24. No. 159. April 1844. S

258 Mr. Hen wood on the Heaves

It is stated that the great difficulty is to draw clear and consistent
lines of demarcation between these great primary divisions. They
pass into one another, and interchange some fossil species, especially
near their limits. Were it not for the magnificent sections of the old
red sandstone in the British Isles, and also in the north-eastern
parts of Europe (as now shown by Mr. Murchison and his fellow
labourers), the author asserts, that the second and third divisions
would probably be confounded and eventually pass under one common
name (including Upper Silurian and Devonian). In Belgium and the
Rhenish provinces the demarcation between them is quite arbitrary.
We there find Goniatites and long- winged Spirifers and other organic
types (first supposed to characterize the " Devonian system") abun-
dant in the Silurian rocks : and there is nothing in the physical
structure of those countries to suggest the separation of these two
divisions. By help of the British sections, combined with new facts
brought to light in Russia and America, the second division must
however maintain its place.

Between the third and fourth divisions there appears to be a much
better marked separation, both physically and zoologically, than be-
tween the others. These two divisions (at least in North Wales)
differ in structure, interchange hardly any fossil species, and through
large districts are unconformable. Hence they belong to two systems,
and not to one, if the word system be used in a definite sense, and be
applied to the successive divisions (such as the Devonian). To avoid
incongruity of language, the author uses the word system in a ge-
neral sense ; and under the name Palaeozoic System describes the
whole series of formations comprehended under the four divisions
above described. In this great descending series the " Silurian
system" (in the sense in which the words were first used) stands
in the place of the third, and the upper part of the fourth primary
division.

XXXIX. On the Heaves of Metalliferous Veins by Cross-veins.
—Part II. By William Jory Henwood, KB.S., F.G.S.,

Mining Engineer, eye*

(II.) TNTERSECTIONS of lodes affording different ores
■*- by cross-veins of different compositions. — Throughout
tracts of small extent the composition of the rocks is usually,
in some measure, uniform, so that the lodes within such given
tracts present nearly the same characters. This general fact
applies with even greater certainty to the cross- veins, whose
characters are still more uniform ; for they consist for the most
part of quartz and clayey portions of the contiguous rocks ;
and with the exception of lead ores, and these not abundant,
the metallic matters which they contain are in small quanti-
ties, and dispersed through very limited portions of them.

* Communicated by the Author .- Part I. will be found in our preceding
Number, p. 180.

of Metalliferous Veins by Cross-veins, Part II. 259

Of the 233 intersections particularized in my last commu-
nication, 125 are by clayey cross-veins (Jlucans), and 108 by
quartzose ones (cross-courses); being 53*7 per cent, by the
former, and 46*3 by the latter.

(a) Of the 125 intersections by Jlucans — percent.
Those unaccompanied by heaves are 17*6

... heaved towards the right-hand 55*2

left-hand 27'2

greater angle 70'4<

smaller angle 12*0

Of 103 lodes which are heaved by Jlucans —

The tin lodes are 24*2

... lodes yielding both tin and copper ores .... 5*8

... copper lodes 70*0

Of 22 lodes which are intersected by Jlucans without being
heaved —

The tin lodes are 1 3*6

... lodes yielding both tin and copper ores .... 59*1

... copper lodes 27*3

Of 28 tin lodes which are intersected by Jluca?is —

Those which are heaved are 89*3

not heaved 10*7

Of 19 lodes affording both tin and copper ores and inter-
sected by Jlucans —

Those which are heaved are 31 '6

not heaved 68*4

Of 78 copper lodes which are intersected by Jlucans —

Those which are heaved are 92*3

not heaved 7'7

feet
The mean distance of all the heaves by Jlucans is . . 21'5
the heaves of tin lodes .... 19'3
lodes yielding both

tin and copper ores 16*5

copper lodes . . 22*7
The average distance of heaves to the right-hand by Jlu-
cans is 24*4-

left-hand . . . 15'3
greater angle . . 21*7
smaller angle . . 202

(b) Of the 108 intersections by cross-courses (quartzose
cross-veins) — percent.
Those unaccompanied by heaves are 28*7

... heaved towards the right-hand 44"4«

left-hand 26*9

S2

260 Heaves of Metalliferous Veins.

percent.

Those heaved towards the greater angle 59*3

smaller angle 12*0

Of 77 lodes which are heaved by cross-courses —

The tin lodes are 19-5

... lodes yielding both tin and copper ores . . . . 41*5

... copper lodes 39*0

Of 3 1 lodes which are intersected by cross-courses without
being hearted —

The tin lodes are . ■ 22*6

... lodes yielding both tin and copper ores .... 29'0

... copper lodes 48*4

22 tin lodes are intersected by cross-courses, and of them —

Those which are heaved are 68#2

not heaved 31*8

41 lodes in which tin and copper ores are mixed are inter-
sected by cross-courses, and of them —

Those which are heaved are . 78*0

not heaved 22*0

45 copper lodes are intersected by cross-courses, of which

Those which are heaved are 66" 7

not heaved 33*3

feet.
The average distance of all the heaves by cross-courses is 10*5
the heaves of tin lodes . . . . 12*6
the lodes yielding

both tin and copper ores 14*1

copper lodes. . . 6*1
The mean distance of heaves by cross-courses towards the

right-hand is 12-3

left-hand .... 7*1
greater angle . . . 9'3
smaller angle . . . 16*3
It is a remarkable but well-known fact, that in Cornwall
the extent of the heaves by flucans is much greater than of
those by cross-courses. It is also not unworthy of notice that
the flucans heave the copper lodes further than they do the
others, whilst the cross-courses heave them much less. The
right-hand are larger than the left-hand heaves, both by flu-
cans and cross-courses ; but, with the former, the heaves towards
the larger angle are greater than those towards the smaller
angle, whilst with the latter the heaves to the smaller are of
much greater extent than those to the larger angle.

Morro Velho Gold Mines, Brazil, W. J. HENWOOD.

December 7, 1843.

[ 261 ]

XL. A Chemical Investigation of the Organic Bases contained
in Coal-Gas Naphtha. By Dr. Augustus William
Hofman, Assistant in the Giessen Laboratory.
[Continued from p. 205 and concluded.]
2. Leucol*.

(COMPOSITION.— The method for preparing the leucol
employed in the determination of its amount of carbon,
has already been given.

Its nitrogen was determined in a gaseous state by burning
with oxide of copper, in an atmosphere of carbonic acid. I
employed for the latter analysis the basic oil which was ob-
tained from the double salt of mercury and leucol.

Four analyses : — I. 0'3096 grm. of leucol gave 0*9349 grm.
of carbonic acid, and 0*1826 grm. of water.

II. 0*33 grm. of leucol gave 0*9991 grm. of carbonic acid,
and 0*186 grm. of water.

III. 0*4-91-7 grm. of leucol gave 1*4915 grm. of carbonic
acid, and 0*2715 grm. of water.

IV. 0*745 grm. of leucol gave 67 cubic centimetres of ni-
trogen. Thermometer 32° Fahr. ; barometer 0*76 metre.

These analyses give the following per cents. : —

IV.

11*275

which correspond with the formula C18 H8 N, as will be at
once seen by comparing the mean amount of the numbers
found by experiment with the calculated results.

Per centage composition.

1 8 atoms of Carbon .
8 ... Hydrogen
1 ... Nitrogen.

1642*28 100*000 100*646

In order to verify the above formula, I prepared the double
compound of hydrochlorate of leucol and chloride of platinum.
The salt employed for this analysis consisted of different sam-
ples, dried at 212° Fahr., at which temperature scarcely any
change of weight is observed.

I. 0*7814 grm. of chloride of platinum and leucol gave
0*2287 grm. of platinum = 29*268 per cent.

* The name leucol (derived from ~Kivx.og and oleum, because it produces
no coloured reactions), is not well chosen. I cannot however at present
substitute another.

I.

II.

III.

Carbon .

83*041

83*250

82*911

Hydrogen

6*553

6*262

6*097

Nitrogen .

10*406

10*488

10*992

100*000

100*000

100*000

Theory.

Mean found

1365*40

83*140

83-067

99*84

6-079

6-304

177*04

10-781

11-275

262 Dr. A. W. Hofinan on the Organic Bases

II. 0*5967 grm. of chloride of platinum and leucol gave
0-1737 grm. of platinum = 29*110 per cent.

The annexed atomic weights were deduced from these
analyses : — i. II.

1640-57 1663-44

The arithmetic mean of which does not differ much from the
calculated atomic weight 164228.

Leucol therefore contains no oxygen, and it is thus analo-
gous in its chemical composition to the other volatile bases,
with which it possesses a great similarity in its reactions.

A short time after I had commenced the investigation of
this base, I was inclined to consider it the same as that which
Gerhardt* obtained by the action of hydrate of potash on
quinine, cinchonine and strychnine. The composition of chi-
noiline in 100 parts is not very different from leucol, and the
two bodies possess a strikingly similar odour. Nevertheless I
soon convinced myself that they were totally distinct, their be-
haviour towards a solution of chromic acid being quite dissi-
milar ; for whilst chinoiline and its salts give a beautiful orange-
yellow crystalline precipitate, leucol is oxidized and converted
into a black resinous oil.

Properties of Leucol.

This base can be obtained sufficiently pure by distillation.
Having noticed, however, the difference between the cyanol
procured from its salts and that obtained by distillation, I se-
parated leucol from the double salt of mercury (which will be
described more minutely hereafter), by treating the solution
of this salt in hydrochloric acid with hydrosulphuric acid
until the mercury was entirely removed, evaporating and di-
stilling with potash. The leucol obtained in this process dif-
fered from that purified by distillation only, by having lost the
last trace of colour.

The colourless oil possesses an unpleasant odour, at the
same time slightly resembling oil of bitter almonds. Its taste
is more burning than cyanol ; it does not solidify at a tem-
perature of — 4° Fahr., and is less volatile than cyanol. Its
boiling point is 462°*2 Fahr., that is, 134°*6 higher than the
other base.

It burns with a bright smoky flame. Exposed to the air it
becomes resinous. It cannot be distilled without leaving a
slight yellow residue; owing to this I failed in my attempt to
determine the specific gravity of its vapour. Leucol is heavier
than cyanol, its specific gravity being 1*081 at 50° Fahr.

Leucol is still less soluble in water than cyanol ; hot water
* Annal. de Chim. et Pkys. 3me ser. vol. vii p. 252.

contained in Coal-gas Naphtha. 263

dissolves it more readily than cold. It is abstracted from a
watery solution by aether. Alcohol, hydrate of oxide of me-
thyle, acetone, aldehydersulphuret of carbon, fatty and essen-
tial oils, are miscible with leucol in every proportion. It be-
comes cloudy with hydrochloric acid, and gives the same re-
action as cyanol with dahlia paper. It resembles this body
also in its behaviour towards sulphur, phosphorus, arsenic,
camphor, colophony, copal and caoutchouc. Leucol does not
coagulate albumen.

The strong dispersive and refractive power of this body is
very remarkable; in this respect it greatly surpasses cyanol.
Its index of refraction is 1'645, exactly the same as that of
sulphuret of carbon.

It is a very bad conductor of electricity, as the deviation of
the galvanometer was still smaller than with cyanol.

Leeches are killed when submerged in an aqueous solution
of this base. I injected about 0*5 grm. of this base, mixed
with water, into the throat of a rabbit, but spasms were not
brought on, as with cyanol. The animal, after once throwing
back convulsively its head, was seized with a total prostration
of all strength, which lasted for some hours. The pupil did
not sensibly dilate, and when the oil was dropped into the eye,
a contraction took place. On the following day the rabbit
had perfectly recovered.

Leucol is distinguished in its reactions from cyanol, by not
producing a blue colour with solutions of chloride of lime or
chromic acid.

This base produces ill sulphate of copper a light blue pre-
cipitate, which is not altered by boiling. The precipitates
produced by leucol in solutions of the salts of peroxide of
iron, alumina, chlorides of mercury, platinum, palladium, gold,
antimony and protochloride of tin, correspond, both in colour
and other properties, with those produced by cyanol. It ren-
ders the solution of salts of lead and sulphate of protoxide of
iron slightly turbid, and gives with infusion of galls a brownish-
yellow deposit, which is peculiar to the organic bases. The
solutions of other reagents are not changed by leucol.

Combinations of Leucol.

Leucol dissolves readily in all acids with evolution of heat,
but its salts, like those of nicotine and coniine, are not ob-
tained in a crystallized state with facility, which distinguishes
them from the analogous compounds of cyanol. Coniine is in
its saturating capacity the next to leucol.

The odour of the base disappears entirely in its salts. The
fixed alkalies decompose its compounds, the leucol separating

264 Dr. A. W. Mofman on the Organic Bases

in clots, which unite in a short time, forming a clear oily stra-
tum. Ammonia also effects this change, although leucol at
a higher temperature decomposes with the greatest facility the
ammoniacal salts. When a few drops of cyanol are added to
a dry leucol salt, the odour of the latter base is instantly de-
veloped ; a proof that leucol is a weaker base than cyanol.

Sulphate of Leucol. — When anhydrous leucol, a solution in
water or alcohol is mixed with sulphuric acid, no crystals are
obtained ; the liquid, if placed under a bell jar, inspissates,
and gradually becomes a viscid syrup. If some drops of con-
centrated sulphuric acid are added to an jethereal solution of
leucol, the compound produced separates as a glutinous liquid
and falls to the bottom of the vessel. By allowing the whole
mixture to repose in a corked flask for some days, crystals are
gradually deposited. I removed the aether and dissolved these
in absolute alcohol, whereby better crystals were obtained j
but they were so deliquescent as to be unfit for analysis.

Oxalate of Leucol. — I could only obtain this salt as a con-
fused, radiated, glutinous mass, which was deposited when the
solution had reached a certain point of evaporation. This is
quite contrary to Runge's description of the oxalate of leucol;
he says, that the facility with which this salt crystallizes is its
marked characteristic. The crystalline mass is copiously
soluble in aether, alcohol, and water. This property enables
us to separate it with the greatest ease from cyanol ; to effect
this separation the crude bases are dissolved in alcohol or
aether, to which is added an alcoholic solution of oxalic acid.
Some hours afterwards the oxalate of cyanol deposits in white
crystals, while all the leucol remains in solution. My expe-
riments do not correspond in this respect with those of Runge,
who found that the oxalate of leucol separated first in crystals.
The leucol is obtained pure by distilling the mother liquor
with potash, and changing the receiver so soon as the distillate
gives no blue reaction with chloride of lime.

Nitrate of Leucol. — This crystallizes the best of all the
leucol salts ; it is obtained by allowing a mixture of leucol and
dilute nitric acid to remain under a bell jar. From the amber-
coloured solution the salt crystallizes after some time in con-
fused concentric aggregated needles, which can be obtained
white and dry by pressing them between folds of bibulous
paper. They are extremely soluble in water and alcohol, and
crystallize readily from the latter ; insoluble in aether. When
exposed to the air they become quickly blood-red. On being
moderately heated the crystals melt to a clear liquid, and when
the temperature is increased, a colourless gas is expelled, which
condenses in starry crystals upon the upper part of the tube.

contained in Coal-gas Naphtha. 265

Hydrochlorate of Leucol. — This salt is very seldom'obtained
in crystals. The mixture, when placed under the air-pump
receiver, became a thick syrup. When dry hydrochloric acid
gas is directed upon the surface of an ethereal solution of
leucol, the compound separates in globules, which subside in
the form of a tenacious stratum, and after a very long time
small crystals appear.

Chloride of Platinum and Leucol. — This compound preci-
pitates of an orange-yellow colour (rather lighter than the
analogous cyanol compound), when a solution of hydrochlo-
rate of leucol is mixed with chloride of platinum. It is spa-
ringly soluble in water and hydrochloric acid, less so in alco-
hol and aether. A mixture of the two serves very well for
washing the salt. The chloride of platinum and leucol is de-
posited as a warty crystalline mass by spontaneous evaporation
from an aqueous or hydrochloric solution.

Analysis of this salt: — 1*0528 grm. of chloride of platinum
and leucol gave 1-2377 grm. of carbonic acid, and 0*2445 grm,
of water.

0*892 grm. of chloride of platinum and leucol gave 1*120
grm. of chloride of silver.

The determination of platinum has been already mentioned.
The above results agree with the formula CI H, C18 H8 N

+ Cl9Pt.

Composition in per cents.

Th

eory.

Found.

18 atoms

of Carbon

1365-40

32-385

32-329

8

Hydrogen

112-32

2-664-

2-580

1

Nitrogen .

177*04

4*199

3

Chlorine .

1327-95

31-4-95

30-964.

1

Platinum .

1233-50

29-257

29*268

29-110

4216-21 100-000

Chloride of Mercury and Leucol is a white crystalline preci-
pitate, produced by treating an alcoholic solution of leucol
with chloride of mercury. For the preparation of this salt
too small a quantity of the spirit must not be employed, be-
cause in such a case the compound is deposited as an unc-
tuous mass upon the sides of the vessel. This salt is analo-
gous to the corresponding one of cyanol ; with this exception
it is not decomposed by boiling water.

Analysis of this salt dried in the air: — 1-2503 grm. of chlo-
ride of mercury and leucol gave 1*2045 grm. of carbonic acid.

0 6259 grm. of chloride of mercury and leucol gave 0-446
grm. of chloride of silver.

1-0875 grm. of chloride of mercury and cyanol gave 05427
grm. of mercury.

Tiieory.

Found.

1365*40

26*988

26492

99*83

1-973

177-04

3-499

885-30

17*500

17*568

2531-65

50-040

49-903

5059-22

100-000

266 Dr. A. W. Hofman on the Organic Bases

The composition is represented by the formula C18 H8 N
+ 2(CiHg).

Composition in per cents.

18 equiv. Carbon .
8 ... Hydrogen

1 ... Nitrogen .

2 ... Chlorine .
2 ... Mercury .

Leucol forms double salts with protochloride of tin and
chloride of antimony. The first presents itself as a yellow oil,
which after some time becomes crystalline, when a solution
of hydrochlorate of leucol is mixed with protochloride of tin.
It is sparingly soluble in alcohol. The salt of antimony is
obtained crystallized, by boiling in hydrochloric acid the pre-
cipitate produced by leucol in chloride of antimony, and al-
lowing the mixture to cool. The only other salt of this base
1 shall mention is the carbazotate, which is in every respect
analogous to the corresponding salt of cyanol.

Decomposition of Leucol.

I have not proceeded far with this investigation ; but at the
outset the products of decomposition of this base do not ap-
pear nearly so interesting as the numerous metamorphoses of
cyanol.

An aqueous solution of chromic acid converts leucol into a
resinous mass, whereas the dry acid, when brought in contact
with anhydrous leucol, inflames it, as in the experiment with
cyanol. This effect is also produced upon nicotine, coniine,
chinoiline and sinnamine. I repeated this experiment with
some of the solid bases, as naphthalidam, thiosinnamine, sina-
poline, cinchonine and narcotine, and found that inflammation
also took place when any of the preceding bodies were slightly
heated with chromic acid. On the contrary, oil of mustard,
benzol, nitrobenzide, nitronaphtalase and carbolic acid are
not affected, even when the mixture is warmed. It appears
from this, that only the strong affinity between base and acid
is capable of producing the necessary temperature for ignition.

When leucol is treated (in a similar manner to that de-
scribed under cyanol) with a solution of hydrochloric acid and
chlorate of potash, the liquid becomes covered with a layer of
an orange-red oil, which, upon cooling, solidifies into an olea-
ginous mass, completely insoluble in water, but readily dis-
solved by hot alcohol ; it separates again upon cooling in an

contained in Coal-gas Naphtha. 267

amorphous state. Treated with nitric acid this substance did
not produce carbazotic acid.

By transmitting a stream of chlorine gas through leucol,
the temperature greatly increases, with formation of a black
resinous substance and evolution of hydrochloric acid.

The body formed by the action of bromine upon leucol and
solutions of its salts appears to be of a similar nature. It is
insoluble in water, slightly soluble in alcohol or a2ther, and
deposits from the solution as an amorphous powder.

Iodine dissolves in leucol, but no crystals are obtained.

Nitric acid, even fuming, attacks leucol very tardily. After
the base had been five times redistilled with this acid, the
greater part of it separated unchanged on the addition of
potash. By the long-continued action of a large excess of
nitric acid, the oil was at length converted into a brown mass,
which admitted, while warm, of being drawn into long
threads, but upon cooling became a friable resin. It possessed
a bitter taste, dissolved easily in potash, and was not carba-
zotic acid.

Leucol (as well as cyanol) is decomposed into oxalic acid
and ammonia by hypermanganate of potash.

Potassium dissolves in leucol, disengaging hydrogen, but
no coloured compound results. When this metal is melted
in an atmosphere of leucol, cyanide of potassium is formed.
I was anxious in this decomposition to ascertain what became
of the other elements of the base. In order to perform the
experiment on a more extended scale, I conducted the vapour
of the oil over a layer of carbonized tartar, by which means I
expected to replace the potassium. However in this process
only a small quantity of cyanide of potassium was formed, and
the greater part of the leucol passed over unchanged. The
property which this base possesses of resisting decomposition
at high temperatures is particularly characteristic, but readily
explicable when we consider the enormous degree of heat at
which it is produced in the retorts of gas-works. Leucol may
be passed over caustic lime at a white heat without suffering
decomposition.

From the preceding researches, although as yet so incom-
plete, no other conclusion can be drawn, but that leucol be-
longs to quite a different type of compounds from cyanol ; and
further investigations must solve the problem as to what series
of bodies leucol bears a relation.

[ 268 ]

XLI. On the Gas Voltaic Battery. — Experiments made with
a view of ascertaining the rationale of its action and its ap-
plication to Audiometry. By W. R. Grove, Esq., M.A.,
F.R.S., Professor of Experimental Philosophy in the London
Institution*.

TN the Philosophical Magazine for December 1842, I have
published an account of a voltaic battery in which the
active ingredients were gases, and by which the decomposi-
tion of water was effected by means of its composition.

The battery described in that paper consisted of a series of
tubes containing strips of platinum foil covered with a pulveru-
lent deposit of the same metal ; the platinum passed through
the upper parts of the tubes, which were closed with cement,
the lower extremities were open ; they were arranged in pairs
in separate vessels of dilute sulphuric acid, and of each pair
one tube was charged with oxygen, the other with hydrogen
gas, in quantities such as would allow the platinum to touch
the dilute acid ; the platinum in the oxygen of one pair was
metallically connected with the platinum in the hydrogen of
the next, and a voltaic series of fifty pairs was thus formed.
With this battery the following effects were produced : —

1st. A shock was given which could be felt by five persons
joining hands.

2nd. The needle of a moderately sensitive galvanometer
was whirled round and remained permanently deflected 60°.

3rd. A gold-leaf electroscope was notably affected.

4th. A brilliant spark visible in broad day-light was given
between charcoal points.

5th. Iodide of potassium, hydrochloric acid, and water
acidulated with sulphuric acid were severally decomposed ;
the gas from the decomposed water was collected and deto-
nated. The gases were evolved in the direction which the
chemical theory would indicate, the hydrogen travelling in one
direction throughout the circuit, and the oxygen in the reverse.

When distilled was substituted for acidulated water in the
battery cells, the effects were similar but more feeble.

The effects, though clear and decisive in themselves, were
further tested by counter experiments, such as reversing the
current by reversing the gases, &c; but these I need not here
detail, as the electrical effects of the gas battery, when charged
with oxygen and hydrogen, have since the publication of that
paper been repeatedly verified. I further stated, that when
carbonic acid and nitrogen were substituted for oxygen and

* From the Philosophical Transactions for 1843, part ii. ; having been
received by the Royal Society March 27, and read May 11, 1843.

Mr. Grove on the Gas Voltaic Battery. 269

hydrogen, no voltaic effects were produced ; that oxygen and
nitrogen produced no effects, but that hydrogen and nitrogen
did produce a voltaic current, which I attributed to the com-
bination, with the hydrogen, of the oxygen of atmospheric air
in solution; this opinion will be further tested in the follow-
ing paper.

The voltaic current generated by this battery I attributed
to chemical synthesis, of an equal but opposite kind, in the
alternate tubes, at the points where the liquid, gas, and pla-
tinum met, and the object of covering the platinum with the
pulverulent deposit*, was to increase the number of these
points, the liquid being retained upon the surface of the pla-
tinum by capillary attraction.

The point which appeared to me at that time as most im-
portant, was the beautiful instance of the correlation of natural
forces exhibited by the fifth effect, in which gases by com-
bining and becoming a liquid, transfer a force which is capa-
ble of decomposing a similar liquid, and causing its constitu-
ents to become gases; heat, chemical action and electricity
being all blended and mutually dependent.

The apparatus with which I made the above experiments
being composed of some pieces of tubing which happened to
be in my laboratory, did not enable me to attain any precise
accuracy of measure as to the volumes of gases absorbed, or
to prove that Faraday's law of definite electrolysis finds no
exception in the gas battery. Since that paper was written I
have, after some failures, constructed apparatus by which I
have been enabled to verify this law and to extend my re-
searches into the nature of gaseous voltaic action. I have felt
the more called on to multiply experiments on this subject, as
a letter has been published on the gas battery, written by an
electro- chemist for whose opinion I have much respect, which
attributes its action to a cause different from that to which I
assigned it.

Soon after my original publication I received a letter from
Dr. Schcenbein, the substance of which has since appeared in
printf . Dr. Schcenbein there expresses an opinion, that in
the gas battery oxygen does not immediately contribute to the
production of the current, but that it is produced by the com-
bination of hydrogen with water. I have recently heard a si-
milar opinion to that of Dr. Schcenbein expressed by other
philosophers, but I must take the liberty of dissenting from it
and of adhering to that which I expressed in my original

* For the method of effecting this see Mr. Smee's paper, Phil. Mag.,
April 1840.

f Phil. Mag., March 1843, p. 105.

270

Mr. Grove on the Gas Foliate Battery.

paper. My grounds of dissent will be seen in some of the
ensuing pages.

In describing the apparatus used in the following experi-
ments, I shall mention three forms of gas battery, with the
first two of which my experiments were all performed; the
latter has only occurred to me while writing this paper. I
have, therefore, not yet had an opportunity of trying it*, but
it appears to me by far the best of the three, though, doubt-
less, superior modifications will shortly be discovered. Fig. 1
represents one of these forms; a, b, c, d is a wide-mouthed
glass jar, into which a wooden plug, a, b, fits tightly by means
of attached pieces of cork ; this wooden cover is perforated to
receive the tubes o, k, of which the size is such that the con-
tent of h shall be double that of o, and which are firmly ce-
mented into it ; the wooden cover is shown in plan in fig. 2 ;

Fig. 2.

Fig. 3.

the piece/ is capable of being detached at pleasure, in order
to introduce a tube for charging the apparatus with gas ; p r,
p' iJ are strips of well- platinized platinum foil, slightly curved
like a cheese scoop to keep them erect and in the centre of the
tube, and riveted or welded to stout platinum wires, which
are hermetically sealed into the glass, and terminate in brass
mercury cups at g, g. This form of battery is charged by in-
verting it so as to fill the tubes with liquid; on reinversion the
tubes may be charged with gas from a crooked tube and blad-
der. The apparatus (fig. 1) is represented as charged and
ready for use, and in fig. 3 is a battery of five cells, also re-
presented as just charged.

* See Postscript.

Mr. Grove on the Gas Voltaic Battery. 271

The advantage of this form over that which I shall next
describe, is the facility with which the tubes are filled with
liquid, and the absence of any necessity of touching the elec-
trolyte with the fingers. On the other hand, its disadvantages
are the difficulty of examining the gases after experiment, and
the impossibility of doing so during experiment without chan-
ging the electrolyte, as in order to examine the gases the whole
apparatus must be immersed in a water-trough, and the cover
with the attached tubes taken off" while the jar and the ends
of the tube are under water.

Fig. 4 represents a cell of the Fig. 4.

second form ; b, c, d, e is a par-
allelopiped glass or stoneware
vessel, such as is commonly used
for the outer cells of the nitric
acid batteries ; the tubes are ce-
mented into pieces of wood, a b,
ac, and can with the wood be
separately detached from the
trough, as shown in fig. 5. At
the aperture or space, a a, be-
tween the tubes there is just
room for a finger to enter, close
the orifice of either tube, and
thus detach it from the appa-
ratus. In this figure the pla-
tinum foil is turned up round
the edge of the tube, instead of
being attached to a wire sealed into the glass, and instead of
a mercury cup there is a binding-screw connexion ; but it is
obvious that this part of the arrangement may be interchanged
with the other apparatus, or varied ad libitum. This appa-
ratus I have found in practice to be very much more conve-
nient than the former, from the facility of detaching either
tube so as to discharge some of the gas, if it be desirable to
alter the level of the water-mark ; or to examine or change the
gas in any of the tubes. On the other hand, it has the disad-
vantage of requiring the finger to be immersed in the electro-
lyte, which, when the latter is of an active chemical character,
is unpleasant and in some cases injurious. In fig. 6, a battery
of five cells of this construction is represented as when charged
with oxygen and hydrogen, and having been for some time
connected with the voltameter (fig. 7), the tubes of which are
of the same size as those of the battery.

In the form last described (figs. 4 and 6), the tubes were all
as nearly of the same size as could be procured ; they con-

272 Mr. Grove on the Gas Voltaic Battery.

tained each about l£ cubic inch ; in the first form (figs. 1 and
8), the portion o, r of the narrow tube contained l£ cubic inch,
Fig. 6. Fig. 7.

\o o\ V2. oh.

Fig. 8.

and the portion h, r1 of the wide tube contained 2^ cubic inches.
A portion of the apparatus with which I wrought was con-
structed by my order for the London Institution, and another
portion belonged to Mr. Gassiot, and was by him very kindly
placed at my disposal for the purpose of these experiments ;
had it not been for this valuable addition, I should have been
obliged to make all my experiments on a much smaller scale ;
they would have taken more time and been by no means so
satisfactory.

As I have already stated, a third
form has occurred to me while writing
this paper, which I think in many re-
spects more advantageous than either
of the two preceding, and which, as
it may be some time before I can ex-
periment with it myself, I will here
describe for the benefit of those who
are differently situated. One cell of
it is shown in fig. 8: a, a, is a Woulfe's
bottle with three necks ; in the centre
neck is fitted a glass stopper, b; in
the other two the tubes o, h fit accu-
rately by means of glass collars (c c,
fig. 9) welded to them and ground on
the outside ; the platinum is hermeti-
cally sealed into the lops of the tubes,
which may be charged in a similar

Mr. Grove on the Gas Voltaic Battery. 273

manner to fig. 1. By immersing this apparatus in the water-
trough, each tube with the gas it contains may be detached and
examined separately, but its principal advantage is, that by
slightly greasing the stopper and collars it may be made per-
fectly air-tight, which, for reasons that will be apparent in the
course of this paper, is a most material point. This appa-
ratus, moreover, being entirely composed of glass and plati-
num, concentrated acid, alkaline or other corrosive solutions,
may be used as the electrolyte, without damaging the appa-
ratus or introducing foreign matter.

In the experiments I am about to describe, the results were
generally tested by chemical action, as manifested by the elec-
trolysis, either of iodide of potassium or of water. I had at
my disposal a highly sensitive astatic galvanometer, but I found
such slight local actions disturb it, that a range of test expe-
riments was in each case necessary to eliminate the true bat-
tery action from the accidental currents; and with all the
pains that could be bestowed upon it, the results were less
definite and trustworthy than those obtained with the iodide.

I may here state also, that, although with the battery de-
scribed in my original paper when charged with oxygen, hy-
drogen and dilute sulphuric acid, I could not succeed in per-
ceptibly decomposing water with less than twenty-six cells,
yet the new arrangements, from their superiority in size and
construction, were capable, when charged with the same gases
and electrolyte, of decomposing water with four cells ; and a
single cell would decompose iodide of potassium.

Experiment 1. — Ten cells charged to a given mark on the
tube with dilute sulphuric acid, sp.gr. 1*9, oxygen and hy-
drogen, were arranged in circuit with an interposed voltame-
ter*, as in figs. 6 and 7, and allowed to remain so for thirty-
six hours. At the end of that time 2*1 cubic inches of mixed
gas were evolved in the voltameter ; the liquid had risen in
each of the hydrogen tubes of the battery to the extent of 1*5
cubic inch, and in the oxygen tubes 0*7 cubic inch, equalling
altogether 22 cubic inches; there was therefore O'l cubic
inch more of hydrogen absorbed in the battery tubes than was
evolved in the voltameter.

* These experiments were made with the battery fig. 1, though for more
clearly showing the volumes of the gases the second form is represented in
figures 6 and 7. The voltameter employed on this occasion had electrodes
of fine piatinum wire a quarter of an inch long. From the nature of the
gas battery it is difficult to know the efficient surface of the plates. In or-
dinary batteries I have found, and stated some time ago, that for quanti-
tative effects, the electrodes should be of the same size as the battery
plates.

Phil. Mag. S. 3. Vol. 24. No. 159. April 1844. T

274

Mr. Grove oil the Gas Voltaic Batt ery.

This experiment was several times repeated with the same
general results; I give some of them in the annexed Table.

Cubic inch of oxy-
gen absorbed m
the battery cells.

Cubic inch of hy-
drogen absorbed in
the battery cells.

Cubic inch of oxy-
gen evolved in vol-
tameter.

Cubic inch of hy-
drogen evolved in
voltameter.

Time.

Number
of cells.

07

05
0-6
06
0-6

1-4

14

1-4
1-3
1-4

07
05
06
0-5
0-6

1-4
11
1-3
1-2
13

36
hours.

10

Mean 0-6

1.34

0-58

1-26

We may observe generally in these experiments, that the
hydrogen evolved in the voltameter is somewhat more than
double the volume of the oxygen, and that a still extra quan-
tity of hydrogen is absorbed in the battery. With regard to
the excess of hydrogen in the voltameter, this, as is well known
to electricians, is always observable in the electrolysis of water,
and has been attributed by Faraday to the more ready solu-
bility of oxygen, and its tendency to form oxygenated water*;
but we have in the above experiments a still greater excess of
hydrogen absorbed in the battery tubes; this result previous
experiments had led me to expect. In one of these I found
voltaic action produced by tubes charged alternately with hy-
drogen and water, and attributed it to the combination of hy-
drogen with the oxygen of atmospheric air in solution f.
Granting for the moment this explanation to be correct, in a
gas battery charged with oxygen and hydrogen we should have,
upon completion of the circuit, three distinct voltaic actions:
— First, the principal action occasioned by the gases in the
tubes reacting upon each other through the medium of the
electrolyte, i. e. reverting to fig. 4, an action in which the por-
tions of the platinum exposed to the gases p q, p' q', would be
the efficient plates. Secondly, an action between the hydro-
gen at p' q' and the air in solution in the neighbourhood of
the immersed portion of the plate y, r ; this would add to the
general current, but would tend disproportionately to diminish
the hydrogen. Thirdly, a local action between the hydrogen
at p\ q' and the air in solution around the part <?', r1 ; this
would add nothing to the general current, but would also tend
to diminish the hydrogen. As this last is totally independent
of the general action, it could be abstracted by merely placing
a cell charged similarly to the battery out of the circuit with
the terminals unconnected as in fig. 1 ; in a cell so placed the

* Experimental Researches, § 716, 71 7-
f Phil. Mag., Dec. 1842, p. 419, Exp. 11.

Mr. Grove on the Gas Voltaic Battery. 275

hydrogen was found to be absorbed in the ratio of rather less
than 0*1 cubic inch in twenty-four hours.

On some occasions I found the rise of liquid in the hydro-
gen cell to be unequal in different tubes of the battery, and
this I found more particularly the case in the battery fig. 4;
it was some time before I discovered the cause of this. I will
not enumerate my different conjectures, but state that which
proved to be the correct one. As, in using the two forms of
batteries (figs. 1 and 4), the chief difference consisted in the
introduction of the finger, it occurred to me that my assist-
ant's hands, which were employed in various manipulations,
might, in placing the tubes in the cells of fig. 4, introduce into
the electrolyte small portions of foreign matter, particularly
metals, and that thus a local action might be occasioned; this
view was strengthened by my frequently observing copper de-
posited upon some of the immersed portions of the platinum,
and where this happened an excess of hydrogen was generally
found to have been absorbed : to examine the accuracy of this
view I caused

Experiment 2. — Four cells to be charged with a solution of
sulphate of copper, and connected in closed circuit; after
twenty-four hours' work, the liquid in the oxygen and hydro-
gen tubes had risen equally in three of the pairs, but in the
fourth the liquid in the hydrogen tube had risen rather more
than twice as high as in any of the others, and the whole of
the platinum in this tube, from the water-mark downwards,
was covered with metallic copper ; it was thus evident that a
slight precipitation having commenced on this platinum from
some local circumstance which offered less resistance in this
cell than in the others, a separate local current had been
established, the hydrogen and the copper acting as a voltaic
circuit, fresh copper had been constantly deoxidated at the
expense of the hydrogen : the phaenomenon is perfectly analo-
gous to that observable in an ordinary sulphate of copper bat-
tery, when a slight portion of copper is deposited upon the
zinc, and a local current is established by which the zinc is
worn into a hole without contributing to the general current.

I have been thus particular in order to explain points in
the action of this battery which might seem exceptions to the
law of definite electrolysis, or what perhaps we should here
call electro-synthesis ; as a general result, the equivalent action
of the battery was very beautiful; with fifty cells in action
there was but a trifling difference in the rise of liquid in all
the cells, and the rise of gas in the voltameter appeared so di-
rectly proportional, that an observer unacquainted with the
rationale of a voltaic battery, would have said the gases from

T2

276

Mr. Grove on the Gas Voltaic Battery.

the exterior cells of the battery were conveyed through the
solid wires and evolved in the voltameter; and had this been
the first voltaic battery ever invented, this probably would
have been the theory of its action.

In my original paper, I considered the points of voltaic
action to be those where the liquid, gas, and platinum met;
and it was to increase the number of these points that I em-
ployed platinized or spongy platinum ; indeed, from what I
have since observed, I have much doubt whether I should
have obtained any success had I used smooth platinum. The
local action detailed in the last experiment, however, made
me anxious to ascertain whether the principal points of action
were those which I had originally believed, or whether the
gases entered into solution first, and were then electro-syn-
thetically combined by the immersed portion of the platinum ;
whether, for instance, the efficient parts of the plates were the
parts p q, p' q' (fig. 4), or q r, q' r1. To ascertain this the fol-
lowing experiment was made : —

Experiment 3. — A battery of five cells
was constructed, in which the platinum
reached only to half the height of the
tubes (fig. 10). This was charged with
oxygen and hydrogen, so that the liquid
just covered the extremities of the
platinum. In this case we have only
the immersed portions of the platinum,
q r, q' 7J, and can examine the action of
the gases which enter into solution, and
are unaffected by the platinum until in
solution. This battery so charged gave
a very trifling action indeed ; it would
not decompose iodide of potassium, and
but slightly affected a highly sensitive
galvanometer ; but when a little gas was
added, so as to expose the platinum to
the gaseous atmosphere, a considerable
current was developed, and a single pair decomposed
iodide.

If, again, a battery of this description (fig. 10) be charged
so that the water-mark is below the upper edge of the plati-
num, and the ends are connected in closed circuit, the liquid
rises in both tubes until that in the hydrogen tube has reached
the top of the platinum, and then there is no further rise.
This experiment decides the question as to what is to be con-
sidered the working portion of the battery, but it does not
positively decide whether solution and electrolysis are con-

the

Mr. Grove on the Gas Voltaic Battery. 277

temporaneous or successive, as it may be said that even what
I have termed the exposed parts of the platinum are covered
with a film of liquid. I should myself hesitate for the present
to express a decided opinion on this point; my first impres-
sion was, that there would be, as it were, three sets of points
in contact, but I have not been able to devise an experiment
definitively to settle this point*.

I aimed next at further establishing the analogies of this
battery with the ordinary voltaic battery, i. e. regarding the
hydrogen tube as analogous to the plate of zinc or other oxi-
dable metal at the anode ; I wished to see how far this rela-
tion was borne out. It was beautifully shown in

Experiment 4. — Where a single pair was charged with
oxygen and hydrogen, and a second with hydrogen in one
tube, the other being filled with dilute sulphuric acid; when
the hydrogen of the second was metallically connected with

Fig. 11.

the oxygen of the first, and the liquid of the second with the
hydrogen of the first, as in fig. 11, bubbles of gas rose from
the platinum, which proved, as I anticipated, to be hydrogen.
In short, though it required four pairs to decompose water
with immersed platinum electrodes, yet the platinum in the
atmosphere of hydrogen being analogous to an oxidable anode,
one pair was with this assistance sufficient to decompose water,
just as one pair of an ordinary battery will decompose water
with an anode of copper.

* I have sometimes remarked when mixed oxygen and hydrogen have
been collected in one tube of the gas battery over distilled water, the ad-
dition of a little sulphuric acid causes the gases rapidly to disappear.

278 Mr. Grove on the Gas Voltaic Battery.

The nitric acid battery, an account of which I originally
published in 1839, having shown me the value of highly oxy-
genated acids and peroxides as voltaic excitants*, I deter-
mined, with a view of further extending the analogy of the
gaseous and metallic voltaic batteries, to try the nitric acid as
an electrolyte with the gas battery. Therefore,

Experiment 5. — I charged a battery with hydrogen and
nitric acid in alternate cells, the nitric acid being only diluted
sufficiently to prevent injury to the wooden parts of the bat-
tery. With this arrangement I found that three cells were
capable of decomposing water, and thus, here also, the ana-
logy held good, the gaseous hydrogen deoxidating the nitric
acid in this arrangement, just as nascent hydrogen does in the
metallic battery.

I now endeavoured to produce the converse effects, viz. to
form a battery in which oxygen should be the gaseous ele-
ment, and be absorbed by an electrolyte having an affinity for
it. To this end,

Experiment 6. — I caused a battery often cells to be charged,
the one set of tubes with oxygen and the alternate tubes with
solution of protosulphate of iron. This battery decomposed
iodide of potassium, but was not able to decompose water;
the tubes which contained the solution of protosulphate re-
presented the hydrogen tubes of the ordinary gas battery.
The voltaic action caused by oxygen and protoxide of iron
was, however, but temporary i\ After a few hours it abated,
the iodide was no longer decomposed, and the liquid did not
rise perceptibly in the tubes containing oxygen ; the solution
when tested by ferrocyanide of potassium gave a blue precipi-
tate, indicating the presence of peroxide, but the greater por-
tion of this was probably formed at the expense of the atmo-
spheric air.

In the last experiments and others, I had observed that a
more decided effect was obtained when free hydrogen alone
was present than when oxygen was alone. In my former
paper I attributed this to the atmospheric air in solution, and
for convenience of arrangement I have hypothetically assumed
this explanation in the commencement of this paper, but the
recent letter of Dr. Schcenbein induced me to look further
into this point. Therefore,

* See Phil. Mag., May and October 1839, pp. 389 and 290.

t In experiment 26 it will be seen that a continuous current is obtained
from oxygen and a liquid (ammonia); oxygen likewise gives a current with
solution of cyanogen, and probably with many organic compounds.

[To be continued.]

[ 279 ]

X'LII. Facts and Observations relative to the Science of
Phonetics. By Professor Latham.

IN a previous paper (February 1841, Phil. Mag. S. S. vol.
* xviii. p. 124) an attempt was made to investigate the num-
ber and relations of the consonants called mutes, and to indi-
cate under the term phonetics the particular department of sci-
entific inquiry that employed itself upon the nature, affinities,
and arrangements of the elementary articulate sounds in lan-
guage. Upon these points both grammarians and physiologists
have left much to be done, whilst all that has been firmly es-
tablished, viz. the nature and affinity of the vowels, has been
the work of the natural philosopher. Similar certainty of ar-
rangement may be introduced amongst the consonants.

It has been shown already that the number of the mutes is
neither more nor less than sixteen. These fall into four di-
visions, each division consisting of four sounds, allied to each
other and forming a series, e. g.

p b f v

t d\%

k g x' y*

+ * 9* £

For these series of four sounds the term quaternion is con-
sidered a convenient name. Hence we may speak of the qua-
ternion represented by /?, the quaternion represented by t, the
quaternion represented by k, and the quaternion represented
by s. Such, up to a certain point, is the classification of the
mute consonants.

Beyond this, however, lies the question as to the order and
arrangements of the quaternions themselves. Undoubtedly
we might speak of the sound of/? as belonging to the first, of
the sound of s as belonging to the last quaternion, and of the
sounds of/ and k as belonging to the intermediate ones. In
other words, we could give a fixed order of sequence to the
quaternions, to which, if convenience required, and the lan-
guage of scholars was uniform, we might rigidly adhere. Such
an order, however, would only be arbitrary and artificial, or,
if it were natural, would be so only by accident. The ques-
tion to which the present notice is devoted, is the natural ar-
rangements for the quaternions founded upon the affinities of
the sounds themselves. To establish this would be to give so
much precision to the department of phonetics.

Now by bringing into play a new series of affinities we can
ascertain the affinities of the quaternions with each other, and
exhibit the natural arrangement of them.

Over and above the affinities of the mutes with each other

280

Professor Latham on Phonetics.

(P> b>J> v> &c«) there are affinities between the mutes and
liquids. These latter sounds are four in number (/, m, w, r).
Each quaternion has a corresponding liquid, and vice versa;
that is,

m is akin to b and consequently to p f v
n ... t ... ... d y $

I ... k ... ... g x y

r ... s ... ... S o" £

Now it is clear that to ascertain the natural order of the
liquids is to ascertain the natural order of the quaternions, and
vice versd; so that, if m and n, as liquids, are allied to each
other, b and t, as mute, must be similarly allied; or, at least,
follow the same arrangement. On the other hand, if t and s,
as mutes, are allied to each other, n and r, as liquids, must be
similarly allied and follow the same arrangement. Now such
is really the case, m and n, t and s are allied each to each ;
and the alliance or affinity is evident, palpable, and recog-
nised. This gives us, up to a certain point, a natural arrange-
ment, e. g. quaternions p and t must come together, because
the liquids to which they are allied (m and n) come together ;
whilst the liquids r and n must come together, inasmuch as the
mutes to which they are allied (s and t) come together. This
gives us

d ]> 3
z <r' $
in a natural, absolute, and necessary order of sequence.

Of the liquid I the affinities cannot be said to be unequivo-
cally clear, neither are the affinities of k, g, x', y'. Hence the
place of / and its corresponding quaternion is in a certain
degree doubtful. All that we say respecting it is, that it has
no place between m and n; in other words, that it must either
precede the one or follow the other. To which of these two
positions it belongs, being determined by the application of
iresh facts, may form the subject of another notice. At pre-
sent we conclude with stating, that in the mutes and liquids
there is a natural order of arrangement, which is either

or

in

V

n

t

r

s

m
n

V b f V
t d \ 3

r
I

S Z <T £

k g x y

I

m
n

k g x y
p b f v
t d \ 3

r

s z <j £".

[ 281 1

XLIII. Professor Th. Bischoff's Reply to Dr. Martin
Barry's "Remarks" on his " Entvoickelungsgeschichte des
Kaninchen- Eies"
TN the London, Edinburgh and Dublin Philosophical Maga-
X zine (Jan. 1844., No. 156, p. 42) Dr. Martin Barry has
published " Remarks " on my work on the Development of
the Ovum of the Rabbit, which appeared in 1842. As in this
work I was compelled to differ in many instances from Dr.
Barry's statements on the subject and to point out many errors
and misconceptions into which he had fallen, I was prepared
to expect something from him in reply, but certainly not such
as he has just published. I treated Dr. Barry throughout
with scientific courtesy ; I always gave, as completely as pos-
sible, reasons for my dissent from him ; and if I maintained
the opinion that, whilst it cannot be denied that he is entitled
to praise as a conscientious and scrupulous observer, there is
nevertheless in his observations a want of due perspicuity and
calmness of reflection, a confounding of the essential with the
unessential, and a fantastical overstraining or exaggeration,
I also gave reasons for it. Dr. Barry, on the contrary, has
in his " Remarks " adopted a different line of conduct towards
me. He has thrown out the unworthy imputation, that I have
made use of his labours without acknowledgement ; he alleges
that my figures are poor imitations of his ; that my method of
investigating the ova in the Fallopian tubes is almost the same
as his; that I have in many places turned his results to my
own use without naming him ; and concludes his remarks with
a very offensive and injurious statement in reference to this.

Here, in Germany, it is not necessary for me to repel Dr.
Barry's imputations. Hundreds of persons know that I was
engaged with researches on the development of the ova of the
Mammifera many years before Dr. Barry, and know and knew
also the results of these researches, from the lectures which I
have given every year on the subject. Moreover, Dr. Barry
has, by his continued fantastical papers on the " Blood-cor-
puscles " and on " Fibre " — objects fortunately more attainable
for observation than the ova of mammifera, — rendered his
credit too questionable for me to fear anything from him in
reference to the success and appreciation of my work. Dr.
Barry took care to make quickly known to the British public,
in the Philosophical Magazine, a somewhat over-hasty admis-
sion of his allegations on the part of Prof. Valentin of Bern,
but he does not appear to have shown the same alacrity now
in communicating the more recent opinion of Prof. Valentin
and the mode of reception of his researches by R. Wagner,
Gluge, Kblliker and others. But in England, where all this

282 Professor Th. Bischoff /;* Reply to Ur. Martin Barry.

must be less known, I must solemnly repel Dr. Barry's in-
sinuations.

In the first place, as regards dates: — Dr. Barry appeals to
the circumstance that his Researches were published in the
Philosophical Transactions for the years 1838, 39, and 40.
It is however to be remarked that it is always a considerable
time after their publication that the Philosophical Transac-
tions come into the hands of the German reader: thus I may
mention, as an example, that I did not get hold of the work for
1840, containing Dr. Barry's Third Series, until the beginning
of the year 1842, notwithstanding I had long before sent di-
rectly to London for it through a bookseller. The abstracts
which Dr. Barry gave in the Philosophical Magazine, and
which first became known in Germany through the medium of
Froriep's Neue Notizcn, were so unintelligible, that it was not
easy for any one to make out their meaning. Now I have con-
tinuously, from the year 1834 up to this time, occupied myself
with the development of the Mammifera. In 1838 I had al-
ready ascertained the principal points and made them pub-
licly known, both at the meeting of German naturalists at
Freiburg for that year, and also by publication in Rudolph
Wagner's Physiology, which appeared the same year; and all
this before I even knew of the existence of Dr. Martin Barry.
In April 1842 my memoir had already been delivered in to
the Berlin Academy, and as 1 had but shortly before received
Dr. Barry's Third Series, I certainly could not have made any
material use of it. In fact his works have occasioned me no-
thing but unspeakable trouble and delay, inasmuch as I took
every pains imaginable to find out by observation the source
of his errors.

In the second place, as regards the subject-matter itself,
there is contradiction on the face of it; for Dr. Barry accuses
me of having made use of his results, and yet his displeasure
has been mainly called forth by the circumstance that I have
come to results quite different from his ! The most important
points of my observations are, — the discovery of spermatozoids
on the ovaries and the ova, the division of the yelk during the
passage of the ovum along the Fallopian tube, the develop-
ment of cells out of the globular masses of yelk, and the com-
position of the blastodermic vesicle by the former, the forma-
tion of layers in the blastodermic vesicle, and the whole deve-
lopment of the embryo and its membranes, — points which I
had either made known before Dr. Barry, or in which I wholly
disagree from what he has said in regard to them, or which
have not been observed or ascertained by him at all. It would,
however, tire the reader and serve no purpose to refute the

Professor Th. Bischoff in Reply to Dr. Martin Barry. 283

individual points of cavil raised by Dr. Barry. I will here
notice one of them only, which is of too great importance to
be passed over in silence.

It is known that Dr. Barry alleged that, in the zona pellu-
cida of the mature ovum, he had seen a fissure, and once in
it "an object very much resembling a spermatozoon." I have
at p. 31 of my memoir stated the reasons why I consider this
observation impossible. I then, at p. 32, proceed: — "I con-
sider it much more possible to decide the question by careful
examination of newly fecundated ova, whether a spermatozoon
really penetrates them or does not immediately become in some
manner dissolved. In the small ova of the Mammalia it will
perhaps be for the first possible to examine very accurately
the contents of the ovum for this purpose, and I have in many
cases directed my utmost attention to the point. It is to be
remarked that the ova in the Fallopian tube are always found
covered with numerous spermatozoa, a fact which Barry ap-
pears never to have observed, whereas I have done so more
than twenty times in a great number of ova. I, however,
never could satisfy myself that one of those spermatozoa was
contained in the interior of the ovum. I have indeed on two
occasions, whilst I crushed, with the compressorium under
the microscope, an ovum from the Fallopian tube, seen quite
distinctly a spermatozoon amongst the yelk granules which had
flowed out from the collapsed zona; and it appeared to come
out from the interior of the ovum. But as, as already said,
the ovum is covered all over with spermatozoa which are en-
closed in the layers of the albumen and are very difficult of
removal, deception is here very possible as well as probable.
Still this method is undoubtedly the surest, and with a suffi-
cient quantity of materials will certainly enable us to arrive at
certainty on the point, which appears to me impossible by pur-
suing the mode of investigation adopted by Barry." Dr.
Barry seems to have taken this hint, as he has now recently
communicated two observations, in which he alleges he has
seen spermatozoids in the ova in the Fallopian tube. He has
adduced Mr. Owen as a witness of this observation. The
above quotation from my memoir will secure me against being
supposed prejudiced against the entrance of spermatozoids into
the interior of the ova ; but it will at the same time show why
I consider Barry's alleged observation as still very doubtful.
As the albumen as well as the zona itself are transparent, a
very careful treatment of the object is required to convince
oneself whether the spermatozoids are situated on the zona
and in the albumen, or within the zona itself. We may en-
deavour to determine the point, partly by varying the focus of

284- Professor Th. Bischoff in Reply to Dr. Martin Barry.

the microscope, partly, and with greater certainty, by the re-
moval of the albumen from the ovum with a sharp needle — a
manipulation which it is to be remarked is very difficult. Both
methods always showed me that the spermatozoids, though
on the ova, were outside the zona. When now it is considered
that Dr. Barry in his previous researches never saw the sper-
matozoids on the ova; that moreover he obstinately maintains
that the albuminous investment around the ovum is not con-
sistent throughout, but a membrane inclosing a fluid ; are there
not good grounds to doubt the correctness of his observation ?
I have been surprised that Mr. Owen has directly assented to
it. Mr. Owen shows himself in his own works a much more
careful, clear-headed and unprejudiced observer than Dr.
Barry. He must know how difficult it is to assure oneself
of a difficult point with absolute certainty by a microscopical
demonstration ; for one must have the object under his own
management, know it very accurately in its other relations,
and put it to the test in all sorts of ways before he can come
to any certain conclusion. This I request Mr. Owen to do
on the next occasion which presents itself, as I myself will
continue to keep the point in view. In the mean time it is to
be wished that the public may not receive as an established
fact the entrance of a spermatozoid into the interior of the
ovum.

I must further mention, that Dr. Barry labours under an
erroneous impression in believing that a former statement of
his, viz. that my communications in Prof. Wagner's Physi-
ology and the illustrative figures in his Icones are defective,
has incensed me against him. Those communications were
in fact mere fragments, hence I was not at all surprised that
Dr. Barry considered them such. They referred besides to
the ovum of the dog, which Dr. Barry is not at all acquainted
with. I therefore never laid the smallest weight on that state-
ment, and had quite forgotten it. My opposition to Barry has
arisen purely out of the subject-matter itself, and has been
brought forward by me with the greatest reluctance, even on
account of that subject-matter. I do not believe that Dr.
Barry ever had or will have a more patient and attentive reader
than myself. I have spared no pains by repeated perusal and
study to extract the sense from his trifling and minute state-
ments, from his involved and disjointed descriptions. The
difficulties of his style and the indistinctness of his ideas are
so great, that probably his labours would have been little
known, had not I, acquainted with the subject, communicated
them in as intelligible a manner as possible to the German
public. Much however has remained quite unintelligible.

Mr. Sylvester on Combinatorial Aggregation. 285

Formerly I often wished to be personally acquainted with
Dr. Barry, in order to reconcile our discordant opinions by
a reference to conjoint observations, but now his fancy has
so completely got the better of his judgement, and the manner
in which he has treated me is so personal and unworthy, that
I altogether despair of coming to any understanding with him.
I see well that time must decide between him and me, and
this, on account of the difficulty of the object, may yet be long
in coming about.

Th. Bischoff, M.D.,

Giessen,Feb. 10, 1844. Professor of Physiology.

XLIV. Elementary Researches in the Analysis of Combina-
torial Aggregation. By J. J. Sylvester, Esq., A.M.,
F.R.S.*

I^HE ensuing inquiries will be found to relate to combina-
tion-systems, that is, to combinations viewed in an ag-
gregative capacity, whose species being given, we shall have to
discover rules for ranging or evolving them in classes ame-
nable to certain prescribed conditions. The question of nume-
rical amount will only appear incidentally, and never be made
the primary object of investigation f-

The number of things combined will be termed the modulus
of the system to which they belong. The elements taken
singly, or combined in twos, threes, &c, will be denominated
accordingly the monadic, duadic, triadic elements, or simply
the monads, duads, or triads of the system.

Let us agree to denote by the word syntheme J any aggre-
gate of combinations in which all the monads of a given system
appear once, and once only.

It is manifest that many such synthemes totally diverse in
every term may be obtained for a given system to any modulus,
and for any order of combination.

Let us begin with considering the case of duad synthemes.
Take the modulus 4- and call the elements a, b, c, d.

(a .b c.d)i{a .c b . d), (a . d c .b) constitute three perfectly
independent synthemes, and these three synthemes include
between them all the duad elements, so that no more inde-

* Communicated by the Author.

t The present theory may be considered as belonging to a part of ma-
thematics which bears to the combinatorial analysis much the same rela-
tion as the geometry of position to that of measure, or the theory of num-
bers to compilative arithmetic; number, place, and combination (as it
seems to the author of this paper) being the three intersecting but distinct
spheres of thought to which all mathematical ideas admit of being referred.

X From avv and -riOripi.

286 Mr. Sylvester's Elementary Researches in the Analysts of

pendent synthemes can be obtained from them. Again, let
a, b, c, d, e,f be the monads ; we can write down five inde-
pendent synthemes, to wit,

a . b c .d e .f-

a .d c .f e . b

a.c d. e f.b

a .f b .d c . e

a . e d .f b .c.

We can write no more than these without repeating duads
which have already appeared*.

We propose to ourselves this problem : — A system to any
even\ modulus being given to arrange the "whole of' its duads % in
the form of synthemes; or in other words, to evolve a Total
of duad synthemes to any given even modidus§.

When the modulus is odd, as before remarked, the forma-
tion of a duad syntheme is of course impossible, for any num-
ber of duads must necessarily contain an even number of mo-
nadic elements; but there is nothing to prevent us from form-
ing in all cases what may be termed a bisyntheme or diplo-
theme, i. e. an aggregate of combinations, where each element
occurs twice and no more.

* Such an aggregate of synthemes may be therefore termed a Total.

f Tiie modulus must be even, as otherwise it is manifest no single syn-
theme can be formed. We shall before long extend the scope of our in-
quiry so as to take in the case of odd moduli.

X Triadic systems will be treated of hereafter.

§ It is scarcely necessary to advert here to the fact of the problem being
in general indeterminate and admitting of a great variety of solutions.

When the modulus is four there is only one synthematic arrangement
possible, and there is no indeterminateness of any kind ; from this we can
infer, a priori, the reducibility of a biquadratic equation; for using <p,f, F
to denote rational symmetrical forms of function, it follows that

if(<p'a7b,<Pc7dU .
, 7 — ;, is itself a rational symmetric function
/OPf^.flMn 0£a,b,e,d.
f((pa,d,(pb,c)}
Whence it follows that if a,b,c, d be the roots of a biquadratic equation,
f((pa,b,<pcd) can be found by the solution of a cubic: for instance,
(a + b) x (c-\-d) can be thus determined, whence immediately the sum of
any two of the roots comes out from a quadratic equation.

To the modulus 6 there are fifteen different synthemes capable of being
constructed j at first sight it might be supposed that these could be classed
in natural families of three or of five each, on which supposition the equa-
tion of the sixth degree could be depressed; but on inquiry this hope will
prove to be futile, not but what natural affinities do exist between the totals ;
but in order to separate them into families each will have to be taken twice
over, or in other words, the fifteen synthemes to modulus 6 being redupli-
cated subdivide into six natural families of five each. Again, it is true that
the triads to modulus 6 (just like the duads to modulus 4) admit of being
thrown into but one synthematic total, but then this will contain ten syn-
themes, a number greater than the modulus itself.

Combinatorial Aggregation. 287

For instance, if the elements be called after the letters of
, ,,, , (a.bb.cc.dd.ee.a\ . ,. .

the alphabet, we have \a.c c ,e e ,b b .d d.a)> tI,e bisyntlie-

matic total to modulus 5; and in like manner
a.b b .c c.d d.e e .ff. g g • a "J

a.c c ,e e .g g .b b. d d .ff. a >the total to modulus 7.
a.d d.g g.c c .ff. bb.ee.aj

In general, if n be the modulus, the number of duads is

n. — - — ; n being even, — duads go to each syntheme, and

therefore the total contains (n — 1) of these. If (is) be odd,
then, since always n duads go to a bisynlheme, the number of

such in the total is — - — .
2

Before proceeding to the solution of the problem first pro-
posed, let us investigate the theory of diplothematic arrange-
ment. Here we shall find another term convenient to employ.
By a Cyclotheme, I designate a fixed arrangement of the ele-
ments in one or more circles, in which, although for typo-
graphical purposes they are written out in a straight line, the
last term is to be viewed as contiguous and antecedent to the
first; the recurrence may be denoted by laying a dot upon the

two opened ends of the circle; a.b ,c .d . e will thus denote

a cyclotheme to modulus 5 ; a.b . c . d .e ,f. g.h .k the same

to modulus 9 ; so also is a . b . c, d . e .f g .h.Jc a cyclotheme
of another species to the same modulus. In general the num-
ber of terms will be alike in each division of a cyclotheme.

Now it is evident that every cyclotheme, on taking together
the elements that lie in conjunction, may be developed into a
diplotheme. Thus

1.2.3=1.2 2.3 3.1

i . 2 . 3. 4=1. 2 2.3 3.4 4.1,

(1.2 2.3 3. 1\
4.5 5.6 6.4 I.
7.8 8.9 9.7/

9 Hence we shall derive a rule for throwing the duads of any
system into bisynthemes.

Let m = 3, we have simply abc

m = 5, we write a . b . c . d . e

a . c .e .b . d

288 Mr. Sylvester's Elementary Researches in the Analysis of

The second being derived from the first by omitting every
alternate term ; similarly, below the lines are derived each from
its antecedent.

m = 7, we have a .b .c . d . e .f. g

a.c.e.g.b.d.f

a . e .b .f. c . g . d
A very little consideration will serve to prove that in this

way, m being a prime number^ — - — , cyclothemes may be

formed, such that no element will ever be found more than
once in contact on either side with any other; whence the rule
for obtaining the diplothematic total to any prime-number
modulus is apparent.

Ex. gr. to modulus 7 the total reads thus: —

1st. a.bb.cc. dd.ee .f f. g g . a "|
2nd. a .c c .e e . g g . b b . d d ,J rf. a >
3rd. a . e e . b b .ff. c c ,g g . d d . a J
and no more remains to be said on this special case.

Let us now return to the theory of even moduli, and show
how to apply what has been just done to constructing a syn-
thematic total to a modulus which is the double of a prime
number.

Suppose the modulus to be six, the number of synthemes is
five. Let the six elements, ar, b, c, d, e,/, be taken in three
parts, so that each part contains two of them; let these parts
be called A, B, C, where A denotes a b, B, c d, and C, ef.

Now the duads will evidently admit of a distinction into two
classes, those that lie in one part, and those that lie between
two; thus a b, c d, ef will be each unipartite duads, the rest
will be bipartite.

The unipartite duads may be conveniently formed into a
svntheme by themselves; it only remains to form the four re-
maining bipartite duad synthemes.

Write the parts in cyclothematic order, as below :

ABC.

It will be observed that each part may be written in two po-
sitions ; thus

A may be expressed by 7 or by

c d

B

c j

d '" c

e f

Combinatorial Aggregation, 289

Now we may form a cyclic table of positions as below :

ABC
1 1 1

1 2 2

2 1 2
2 2 1

Here the numbers in each horizontal line denote the synchro-
nic positions of the parts.

On inspection it will be discovered that A will be found in
each of its two positions, with B in each of its two; similarly
B with C, and C with A. In fact the four permutations,
1.1 1.2 2.1 2.2, occur, though in different orders, in any
two assigned vertical columns.

Now develope the preceding table, and we have

ace a df b cf b de

b df bee ade a cf;
and these being read off (the superior of each antecedent with
the inferior of each consequent*) must manifestly give the
four independent bipartite synthemes which we were in quest
of, videlicet

{a.d cfe.b), (a.c d.ef.b), {b.dc.ef.d), (b.c d.fe.a);
these four, together with the synthemefirstdescribed(d!.6c.rf<?./),
constitute a duad synthematic total to modulus 6.

Before proceeding further let us take occasion to remark
that the foregoing table of positions may evidently be extended
to any odd number of terms by repetition of the second and
third places, as seen in the annexed tables of position.

i .1 . 1. 1 . i i . i . i . i . i . i . i

1 .2.2.2.2 \ .2 .2.2.2 .2.2f
2.1.2.1.2 2.1.2.1.2.1.2

2.2.1.2.1 2.2.1.2.1.2.1

Now let 10 be the modulus.

As before divide the elements into five parts, which call
A, B, C, D, E.

The unipartite duads fall into a single syntheme ; the eight
remaining bipartite synthemes may be found as follows : —

* Any other fixed order of successive conjunction would answer equally
well.

t It will not fail to be borne in mind that in operating with these tables
only contiguous elements are taken in conjunction : the first with the second,
the second with the third, the third with the fourth, &c, and the last with
the first; no two terms but such as lie together are in any manner conju-
gated with one another.

Phil. Mag. S. 3. Vol. 24. No. 159. April 1844. U

290 Mr; Sylvester's Elementary Researches in the Analysis of

Arrange in cyclothemes ( — - — in number) the odd mo-
dulus system A, B, C, D, E. We have thus
ABCDE

ACE B p.

Let each cyclotheme be taken in the four positions given in
the table above, we have thus 2x4, i. e. eight arguments.

abcde.a@y$e.abyde.ct(3c$e
a/3y8e, ab c d e, a /3 c 8 e, abyds

acebd.ayefid.uyebd.acefift
a y e /3 8, ac e b d, ac e /3 8, aysbd
And each of these arguments will furnish one bipartite syn-
theme, by reading off, as before, the superior of each antecedent
with the inferior of each consequent ; and the least reflection
will serve to show that the same duad can never appear in two
distinct arguments.

In like manner, if the modulus be 14 and seven parts be
taken, the bipartite synthemes, twelve in number, may be
expressed symbolically thus :

1.1,1.1.1.1.1
+i .2.2.2.2 2.2
+2.1.2.1.2.1.2

<

A.B.C.D.E.F.G
+A.C.E.G.B.D.F >

l+A E.B.F.C.G.D

+ 2.2. 1 . 2. 1 .2. 1 J
Nay more, from the above table, if we agree to name the ele-

A B

ments a * g1, &c, we can at once proceed to calculate each

of the twelve synthemes in question by an easy algorithm. For
instance,

(1 . 2 . 2 . 2 . 2 . 2 . 2) x (A . C . E . G . B . D . F)
= (Ai. Ci C2. E, E2. Gx G2. Bl B2.D,D2. F, F2. A2).
And again,

(2.1.2.1.2.1.2) x (A . E . B . F . C . G . D)
= A2 . E2 Ex . Bx B2 . F2 Fx . Cx C2 . G2 G! . Dx D2 . A! ;

each figure occurring once unchanged as an antecedent and
once changed as a consequent.

If it were thought worth while it would not be difficult, by
using numbers instead of letters, to obtain a general analytical
formula, from which all similarly constituted synthemes to any
modulus might be evolved.

Combinatorial Aggregation, 291

But the rule of proceeding must be now sufficiently obvious ;
the modulus being 2p, we divide the elements into p classes;

p 1 . .

these may be arranged into *—— — distinct forms of cyclothe-

m

matic arrangement, and each of the cyclothemes taken in four

p— 1
positions, thus giving 4 X *-—t — , i. e. 2p — 2 bipartite syn-

themes, the whole number that can be formed to the given
modulus 2 p.

I shall now proceed to the theory of bipartite synthemes to
the modulus 2 m x p, by which it is to be understood that we
have p, parts each containing 2 m terms, and p is at present
supposed to be a prime number; the total number of syn-
themes to the modulus 2mp being 2mp — 1, and 2 m — 1 of
these evidently being capable of being made unipartite; the
remainder, 2 m p — 2 m, i. e. (p — 1) 2 m, will be the number
of bipartites to be obtained * :

V — 1

2m.(p — 1) = *—- — x 4 m ;

^—c — denotes the total number of cyclothemes to modulus p ;

m

4- m, as will be presently shown, the number of lines or syzy-
gies in the Table of position.

To fix our ideas let the modulus be 4 x 3, and let A, B, C
be three parts :

alaiaza^\

bx b2 b3 b4 > their constituents respectively.

C\ C2 C3 C4j

Give ajixed order to the constituents of each part, then each
of them may be taken in four positions; thus A may be
written

a x a2 a3 aA

a2 a3 a4 al

a3 a2 ax a2

a4 ax #2 a3.

Assume some particular position for each, as, for instance,

ax bx cx
«2 Z>2 c2

a3 °3 C3

a4 b4 Cq
and read off by coupling the first and third vertical places of

* In general, if there be t parts of /& terms each, and /a sr be even, the
number of bipartite synthemes is Or— 1) ft, as is easily shown from dividing
the whole number of bipartite duads by the semi-modulus.

U2

292 Mr. Sylvester's Elementary Researches in the Analysis of

each antecedent with the second and fourth respectively of
each consequent ; we have accordingly,

a3.b4 bR.c4 c3.a4.
It is apparent that the same combinations will recur if any
two contiguous parts revolve simultaneously through two steps;
or in other words, that Ar . Bs = Ar+2 . Bs+2, where ft is any
number, odd or even.

Symbolically speaking, therefore, as regards our table of
position, r: s ■= r + 2 : s + 2, or more generally,

= r + 2 ± 4 i : s + 2 + 4 i.
So that 1:1=3:3 2:1=4:3

1:2 = 3:4 2.2 = 4:4

1:3 = 3.1 2.3 = 4:1

1:4 = 3.2 2.4 = 4:2.
There are therefore no more than eight independent un-
equivalent permutations to every pair of parts. Now inspect
the following table of position : —

i . 1 . i 2.1.2

1.2.3 2.2.4
1.3.2 2.3.1

1.4.4 2.4.3

It will be seen that in the first and second, second and
third, third and first places, all the eight independent per-
mutations occur under different names', the law of forma-
tion of such and similar tables will be explained in due time;
enough for our present object to see how, by means of this
table, we are able to obtain the bipartite synthemes to the
given modulus 4x3; the number according to our formula

3 — 1
is 2 x 4 x — - - — = 8, and they may be denoted symbolically

as follows: —

(A R pv /l. 1.1 + 1.2.3 + 1.3.2+ 1.4. 4\
vA-o.^J y+ 2.1.2 + 2.2.4 + 2.3.1 +2.4.3/'

Each of the eight terms connected by the sign of + gives a di-
stinct syntheme ; ex. gr. let us operate on

A.B.C x (2.3.1).
2.3.1 denotes 2.3 3.1 1.2.

2 . 3 gives rise to 2. 3+ 1 +2+2.3+3
= 2.4 + 4.2.

3 . 1 gives rise to 3. 1+1+3+2. 1 + 3
= 3.2 + 1.4.

1 . 2 gives rise to 1 . 2+1 + 1 + 2 . 2+3
= 1.3+3.1.

Combinatorial Aggregation. 293

The syntheme in question is therefore

A2 . B4 A4 . B2 B3 . C2 Bx . C4 Cx . A3 C3 . Av
and so on for all the rest, the rule being that
r: s — r .s + 1 +r + 2.j+ 3.
Now, as before, it is evident that if we look only to conti-
guous terms, the above table of position may be extended to
any number of odd terms, simply by repetition of the second
and third figures in each syzygy ; and hence the rule for ob-
taining the bipartite synthemes to the modulus 4 xp is appa-

7— 1
rent. For instance, let p = 7, there will be 8 x — - — , i. e.

29

8x3 of them denoted as follows : —

f A.B.C.D.E.F.g] f 1-1. LI- LI- 1+2. 1.2.1.2.1.2"
J . I I +1.2.3.2.3.2.3+2.2.4.2.4.2.4

+ A.C.E.G.B.D.F rxj +1.3.2.3.2.3.2 + 2.3.1.3.1.3.1
+ A.E.B.F.C.G.DJ L+1-4,.4.4,-4,«4.4* + 2.4.3.4.3.4.3_

As an example of the mode of development, let us take the
term

A.E.B.F.C.G.Dx2.4.3.4.3.4.3

2 . 4 . 3 . 4 . 3 . 4 . 3 = (2 : 4, 4 : 3, 3 : 4, 4 : 3, 3 : 4, 4 : 3, 3 : 2)
_/ 2.11 4.41 3.1 1 4.41 3.H 4.4l 3.3\\
~V+*.3J +2.2J +1.3J + 2.2 J +1.3/ +2.2 J + 1.1 J /

A.E.B.F.C.G.D=A.E,E.B,B.F,F.C,C.G,G.D,D.A,

and the product

_/A2.Ex E4.B4 Bs.Fj F4.C4 Cg.^ G4.D4 D3.A3\

-VA4.E3 E2.B2 B..F3 F2.C2 fcJ.G, G2.D2 D^aJ'-

Let the modulus be 6 x 3, as before, give ajixed cyclic order
to the constituents of each part, and each will admit of being
exhibited in six positions.

Write similarly as before,

al bx Cj
a<2 o<2 c2

a3 "3 C3

«4 b4 c4
as h C5

a6 "6 C6>

and take the odd places of each antecedent with the even
places of each consequent; it will now be seen that
r\ s — r + 2:s + 2 = r + 4:s + 4,

and the number of independent permutations is — '—- = 2.6;

294 Mr. Sylvester's Elementary Researches in the Analysis of
and so in general, if there be 2 m constituents in a part, the
number of independent permutations is - = 4ra.

2~

The rule for the formation of the table will be apparent on
inspection. I suppose only three parts, as the rule may
alwa}'s be extended to any number by reiteration of the
second and third terms. The table will be found to resolve
itself naturally into four parts, each containing m lines.

Let m = 1, we have

1.1.1

2.1.2

1.2.2

2.2.1

m = 2, we have

1.1.1

2.1.2

1.2.3

2.2.4

1.3.2

2.3.1

1.3.4

2.4.3

m = 3, we have

1.1.1

2.1.2

1.2.3

2.2.4

1.3.5

2.3.6

1.4.2

2.4.1

1.5.4

2.5.3

1.5.6

2.6.5

m = 4, we have

1.1.1

2.1.2

1.2.3

2.2.4

1.3.5

2.3.6

1.4.7

2.4.8

1.5.2

2.5.1

1.6.4

2.6.3

1 .7.6

2.7.5

1.8.8

2.8.7

{

So that x, going through all its values from 1 to m, the gene-
ral expression for the four parts is

<st(\.x.2x— \ + \.m+x.2x \
\+ 2.x.2x + 2.W + x.2x — 1/
To show the use of this formula, let us suppose that we have
seven parts, each containing ten terms, the general expression
for the bipartite duad synthemes is

( \.x.2x — \.x.2x — l.x.2x — 1
A.B.C.D.E.F.G^I J + 2.x.2x.x.2x.x.2x
+ A.C.E.G.B.D.F > x'Zi L JJ^^x.5 + ^.2x.5^.2T

+ A.E.B.F.C.G.D J r .-— -z T j— « r t^~ 5—

^ + 2.5 + x.2x— 1.5 + x.2x — l.5 + x.2x— 1

Combinatorial Aggregation. 295

Make, for example, x — 3, one of the synthemes in question
out of the twelve corresponding to this value will be
A.C.E.G.B.D.Fx2.3.6.3.6.3.6.
Here
A.C.E.G.B.D.F = A.C C.E E.G G.B B.D D.F F.A

2.3.6
= 2.4 1
+ 4.6
+ 6.8
+ 8.10
+ 10.2

3.6.3

.6 =

3.7"

6.4 *

3.7^

6.4 -

3.7^

6.3-1

+ 5.9

+ 8.6

+ 5.9

+ 8.6

+ 5.9

+ 8.5

\+7.1

^ + 10.8

y+1.l

h + 10.8

+ 7.1

f + 10.7

+ 9.3

+ 2.10

+ 9.3

+ 2.10

+ 9.3

+ 2.9

+ 1.5J

+ 4.2 J

+ 1.5 J

+ 4.2 J

+ 1.5J

+ 4.1 J

:A2.C4,

A4.C6,

and the product

C3.E7 E6.G4 G3.B7 B6.D4 D3.F7 F6.A3
C5.E9, E8.G6 G5.B9 B8.D6 D6.F9 F8.A5,
&c. &c. &c.

To prove the rule for the table of formation, it will be suffi-
cient to show that no two contiguous duads ever contain the
same or equivalent permutations ; the equation of equivalence
it will be remembered isr:s = r + 2/ + 27»:s + 2*+2»*.
Now, as regards the first and second terms, it is manifest that

1 : x cannot be equivalent, either to 1 : x1 nor to 2 : xt nor to

2 . x't where x' is any number differing from x.

Similarly, as regards the last and first term, x : I cannot be
equivalent to x' : 1, nor to x : 2, nor to x' : 2 ; therefore there
is no danger as far as the first term is concerned, either as an-
tecedent or consequent.

Again, it is clear that x : 2 x — 1 cannot interfere with
x1 : 2 x\ nor m + x . 2 x with m + x* : 2 x* — 1 ; neither can
2x — 1 : x with 2 x' : x', nor 2 x : m + x with 2 at — 1 : m + x1.

Again, if possible, let x\ 2 x — 1 = m + x' : 2x' — 1 ;
then m + x1 — x = 2 i

and 2x' — 2x — 2/,
.*. 2 m = 2 i,
or m = r,

which is impossible, since + i is the difference between two
indices, each less than m.

Similarly, m + x : 2% cannot = x':2 x',

and vice versa with the terms changed.

2 x : m + x cannot = 2 x' : x1,

and 2x — 1 : x cannot =2^ — 1 .m + x',

which proves the rule for the table of formation.

So much for the bipartite duad synthemes. As regards the
unipartite synthemes little need be said, for every part may

296 Notices respecting New Books.

be treated as a separate system, and as each will produce an
equal number of synthemes, these being taken onewith another,
will furnish just as many unipartite synthemes of the whole
system as there are synthemes due to each part. Thus then
the synthematic resolution of the modulus 2m x p may be
made to depend on the synthematization of 2 m and the cy-
clothematization of p. This has been already shown (what-
ever m may be) for the case of p being a prime number ; but
I proceed now to extend the rule to the more general case of
p being any number whatever.

[To be continued.]

XLV. Notices respecting New Boohs.

An Inquiry into the Nature of the Simple Bodies of Chemistry. By

David Low, F.R.S.E., Professor of Agriculture in the University

of Edinburgh.
JJIAT experimentum, says Bacon, but the author of this work on a
subject fundamentally experimental, says fiat hypothesis, and he
has accordingly produced a work which may be considered as a ca-
ricature of the ancient doctrine of sulphur, salt and mercury ; a more
correct title to Professor Low's work would have been, Experiment
exploded, or Fancy versus Fact. Dr. Brown may now hide his di-
minished head ; he merely attempted to prove, and to do so by ex-
periment, that one element was convertible into another ; but Pro-
fessor Low, without detailing a single experiment, either good, bad,
or indifferent, has arrived at the following conclusions : — " I pro-
pose," he says, " to show, that we are not entitled to regard these
bodies as elementary or simple, because we have been unable to
overcome the affinities of their constituent parts ; that they cannot
be separated, as natural products, from the bodies which we know
to be compound ; and that all the phenomena of chemical actions
may be equally explained, by assuming the existence of three simple
bodies, or two, or one, as of any greater number." — Preface, p. 1 . He
then proceeds to describe his method of arriving at conclusions : " We
have," says he, " other means of investigation than the processes of
the laboratory, for conducting us to truths in science. We have induc-
tion and analogy, without which even experiment would fail to con-
duct us to the discovery of natural laws ; " and yet with the aid of
these perfect conductors, our Professor, as proved by the passage just
before quoted, has not determined, which he might as well have
done, whether there exist " three simple bodies, or two or one."

Our headlong Professor, by a flourish of his goose-quill, then pro-
ceeds in a manner winch we really know not how to describe as less
than impertinent, to demolish the opinion of Sir H. Davy on the sub-
ject of chemical elements.

The Professor says, that Davy, having examined iodine with "rigid
care," and " finding it to resist all the agents which he employed
to decompose it, pronounced it to be a simple body, according, as he

Notices respecting New Booh. 297

himself expresses it, • to the just logic of chemical philosophy.' The
conclusion was acquiesced in by all chemists ; but the question was
not the more determined, whether this conclusion was arrived at by
the rules of a sound logic or by the admission of an erroneous
dogma."

It certainly required no small degree of assurance to pen a para-
graph like this ; the results of " rigid care " on the part of a chemist
of the highest reputation, and the belief of others in the correctness
of his inference, are in a moment set at nought ; and by what ? by
experiment ? no ; but because the Professor has made the astound-
ing discovery, that by adding together the numbers 14, 4832 and
64-32, or 30 and 96*64, he obtains 126-64. This will appear from
his " Table showing the possible derivation of the Simple Bodies of
Chemistry from common roots," p. 23.

Such is the ground, and such are the facts which, in the opinion
of Professor Low, "should convince us that the rule which we have
adopted is unsound, and is arrived at, not by ' the just logic of chemical
philosophy,' but by a chemical dogma, which ought long ere now to have
been banished from the science into which it has been introduced." Now
this is absolutely monstrous ; here is a person, who, for aught that
appears, never performed a chemical experiment in his life, passing
the sentence of banishment against the opinion of one of the first
chemical philosophers that ever existed. So much for Davy from
Professor Low !

We remember that Dr. George Fordyce used to say, that when-
ever a person was desirous of framing an hypothesis, it was better
that he should know nothing of his subject, for then no facts would
stand in his way. On this principle, the Professor, for anything that
appears to the contrary, may be eminently gifted for the task which
he has undertaken. Or we will suppose the Professor, like Davy, to
have examined iodine "with rigid care," and to have found it "to
resist all the agents which he employed to decompose it," he then pro-
bably would have announced an opinion somewhat like this : this body
is certainly a compound, because the more I have attempted to re-
solve it into two or more kinds of matter, the further have I been re-
moved from success. This we have a right to conclude would be
the Professor's logic on such an occasion.

In further elucidation of Professor Low's mode of advancing the
science of chemistry by "induction," "analogy," and "reasoning
powers," we offer the following choice morsel : — " Now, there are
four roots or elements, into one or more of which, we may suppose
that all the other bodies may be resolved, namely, hydrogen, carbon,
oxygen, and nitrogen, because we know already that these bodies ex-
tend throughout both kingdoms of nature, and that a vast number of
bodies are derived from them, But as there will be seen good reason
for believing, that nitrogen is a compound body, we need not com-
plicate our argument by admitting it into the number of assumed
elements ; but may proceed at once on the supposition, that all bo-
dies may be resolved into three of the number, — hydrogen, carbon,
and oxygen." We afterwards find another assumption, namely that

298

Notices respecting New Booh.

hydrogen and carbon only are the roots of other bodies ; the author
then gives a " Table showing the possible derivation of the Simple
Bodies of Chemistry from common roots." This table shows the as-
sumed composition of fifty-five bodies, at present considered as ele-
mentary. It will be useless to give the whole of this, the extreme
absurdity of it will be sufficiently illustrated by showing the compo-
sition of ten simple bodies.

1. 2. 3. 4.

Simple Bodies.

1. Hydrogen

2. Carbon

3. Oxygen

4- Nitrogen

5. Phosphorus ....

Or,

6. Sulphur

7. Selenium

8. Tellurium

9. Fluorine

10. Chlorine

Derivation from

Derivation

the roots

from the

H.C.O.

roots H, C.

H

C

# #

O

H2 C

C O

H2 C2

H C 0

H3 C2

H3 C202

W C4

H2 C O

H4 C2

Hn C2 02

H15C4

H8 CO4

H16C8

ffCO

W C2

W CaOa

H"C4

Combining
weights deter-
mined by expe
riment.

1

604
8-01
1419
1572
31-44
16-12
39-63
64-25
18-74
35-47

Combining

weights, the

roots being

H, C

1

604
8-04
14-08
15-08
31-16
16-08
39-16
64-32
18-08
35-16

We shall now allude to some statements which occur in the Pro-
fessor's account of what he terms (by a misnomer according to his
" induction ") the " simple bodies of chemistry," which we presume
is given to help to make up a book ; for the properties of these bodies
have nothing whatever to do with his reasoning ; he had merely to
find their atomic weights and calculate what quantities of oxygen,
hydrogen, and carbon, or of hydrogen and carbon would make them
up. There are, however, several statements in this part of the work
on which, could we afford space, we should offer some observations,
but we shall be content with two or three.

We are told that " hydrogen gas, being the lightest of all known
bodies, it is exceedingly convenient to adopt it as the standard by
which the combining weight of other bodies is estimated." Now the
selection of hydrogen for this purpose had nothing whatever to do
with its lightness, for that circumstance does not in the slightest
degree affect the question ; if it did, then nitrogen should be repre-
sented by a lower number than oxygen instead of a higher one, in
the proportion of 14 to 8 ; the reason for selecting hydrogen is the
smallness of its combining weight compared with that of other bodies.

In treating of oxygen the Professor concludes with the following
most extraordinary opinion : — " If we suppose nitrogen to be a com-
pound body, we must, by a parity of reasoning, suppose oxygen to
be so ; for there is no such difference in the chemical characters of
the two bodies, as can allow us to assume that the one is derivative
and the other simple."

Now what are the differences in the chemical characters of these
two bodies ? Let the Professor speak for himself. Of oxygen he says,

Notices respecting New Books. 299

" Bodies which burn in common air, burn, when ignited in oxygen
gas with increased splendour. It is necessary to the respiration of
animals ; " while of nitrogen he says, " It does not support combus-
tion, and all burning bodies immersed in it are in an instant extin-
guished." " It is eminently irrespirable, and no animal can live in
it beyond the briefest period." Now we should like to know what
"differences in the chemical characters" would be sufficient, in the
opinion of Prof. Low, to " allow us to assume," respecting two
bodies, that " one is derivative and the other simple," if those which
he has himself stated with respect to the gases in question, be not
strongly enough marked for the purpose ?

We must now take leave of Prof. Low, not for want of subjects
requiring remark, but because we are really tired with our occupa-
tion ; and in parting we fairly and fervently express the strongest
and well-grounded hope, that " we ne'er shall look upon his like
again."

A Memoir of the Life, Writings and Mechanical Inventions of Edmund
Cartwright, D.D., F.R.S., Inventor of the Power-Loom, $c.
London, 1843, 8vo, pp. viii. and 372. With Engravings in Wood.

This work is interesting as a biography from the picture it exhibits
of the contest between innate genius and external difficulties. For
the first half of his life Dr. Cartwright was a cultivator of the field
of literature. Accidental circumstances having turned his attention
to mechanical inquiries, he suddenly entered upon a new line of re-
search, and speedily accomplished the difficult problem of producing
a steam-weaver, — a machine by which the uniform rotation of a me-
chanical power was resolved into the complicated movements of the
loom. His ideas having once entered this new channel, never wholly
recovered their former direction, but were chiefly applied during the
remainder of his life to subjects of a scientific or mechanical nature.
His machines for combing wool, for making ropes, for working cranes ;
his patent bricks for forming arches without abutments, his agricul-
tural experiments, and a host of other investigations, are all proofs of
the activity and ingenuity of his mind, while his correspondence with
Fulton, Davy, Crabbe, Sir W. Jones, Sir Stamford Raffles, &c, pos-
sesses great historical as well as personal interest. His whole life
was divided between the ornamental and the useful, specimens of
both which are given in the Appendix to this memoir, which contains
a poem eulogized by Sir W. Scott, and an Experimental Essay on
Manures commended by Sir H. Davy. All who duly appreciate the
vast amount of manufacturing prosperity for which Great Britain is
indebted to Dr. Cartwright's inventions, will be interested by peru-
sing in this work the successive steps by which those gigantic results
were attained.

This Memoir has an especial claim on the attention of the readers
of the Philosophical Magazine, from the fact of the subject of it
having been one of our earliest contributors. The first article of
our first Number, published in June 1 798, was a description, accom-
panied by a figure, of Dr. Cartwright's patent steam-engine, in which

300 Royal Astronomical Society.

were introduced the two important principles of dry condensation,
and the metallic piston. From this date, till his death in 1823, Dr.
Cartwright occasionally contributed to our pages. His experiments
on salt as a manure and as a remedy against mildew, and his inven-
tion of a locomotive carriage, are all described in the First Series of
this Magazine (see vols, xxiii. liii. and lvi.).

We think that we observe in the Essay on Manures in the Appendix,
already mentioned, the germs of many of those inductions respecting
the action of manures in general, and their relations to the growth
of plants, which now occupy so considerable a share of the public
attention, and which, both from the dazzling generality and from
the explicitness with which they have been recently brought forward,
have not in all cases been referred to their true authors ; which, re-
garded as new, are in reality due to some of those masters in science,
and some of those insulated experimenters like Dr. Cartwright, who
preceded the present age, and whom neither acceptance nor rejection,
neither praise nor depreciation, can now affect.

The Memoir before us is written in a perspicuous though simple
and unpretending style. Dr. Cartwright's merits and history might
well have been treated in a more elaborate manner and have occu-
pied a larger volume ; but possibly both the mode and the extent
adopted by the author may be more likely to obtain adequate per-
usal and consideration. The theme offers much for reflection, and
itself urges upon the attention of the reader the importance to the
actual well-being and future prospects of society, of encouraging by
every legitimate means those who devote themselves to the invention
and discovery, the improvement and the practical elaboration of
processes of art and manufacture. The grateful regard of individuals
and entire classes, of governments and nations, is alike claimed by
such men as Dr. Cartwright ; but, to make it most effectual in pro-
moting the common good, it should be accorded during their lifetime ;
it should prove the stimulus to the fresh and continued exertion of
those faculties the exercise of which had originally called it forth,
the constantly accruing reward of the self-denial and the innume-
rable trials and privations which even the most successful speculator
or inventor must inevitably endure.

XLVI. Proceedings of Learned Societies.

ROYAL ASTRONOMICAL SOCIETY.
[Continued from vol. xxiii. p. 475.]
Nov. 10, rTPHE following communications were read : —

1843. -* I. Description of a small Observatory constructed at
Poona in the year 1842, accompanied by observations of Eclipses, &c.
of Jupiter's Satellites. By Lieut. W. S. Jacob, R.N. For these
we refer to vol. vi. No. 1 of the Monthly Notices of the Society.

II. The following communications concerning the Great Comet
of 1843*:—

[* Preceding communications on the comet have been noticed in vol.
xxiii. p. 472, &c]

Royal Astronomical Society. 301

1. A Letter from S. C. Walker, Esq., to Sir J. F. W. Herschel.
Communicated by Sir John Herschel.

"Philadelphia, May 23, 1843.

" Sir, — From the observations made at the High School Observa-
tory, from March 11th to April 10th, the earliest and latest dates
at which the place of the nucleus was measured, we have computed
the elements of the orbit on the model of Gauss's Theoria Motus,
without making any hypothesis respecting the particular conic sec-
tion in which the comet moves. The result has been as follows : —

Perihelion passage, February 27d'5893933 Greenwich mean time

Longitude of the perihelion.... 280 44 3-7} Mean March 30
Longitude of the ascending node... 15 57 o'Z J n

Inclination 34 19 52-0

Perihelion distance 0 00410369

Gaussian angle % 2°26'12"-05

Eccentricity, sec. % 1*00090495

Mean sidereal daily motion 1 59 "*58936 retrograde.

" The normal places used were —

March 20'5. March 30*5. April Q'5.

Mean time, Mean time, Mean time,

Greenwich. Greenwich. Greenwich.

From the app* equinox Geo. R.A. 46 4 38-4 59 51 1-2 68 56 41-6

Decl. —9 9 45-5 -6 36 32-5 —4 45 357

Errors of the hyperb. ephem. R.A. —0-6 +0*0 —0-6
Decl. +07 —10 +0-3

" Our observations were made with a 9 -feet Fraunhofer, power
75, and with a Fraunhofer filar micrometer. The places of the stars
used for comparison were taken from the Histoire Celeste and Bessel's
Zone Observations. A small error in our measures, or in the star
catalogues, in the declination of the comet, causes a great change in
the elements. Still, allowing to that source of error all the weight
to which it is entitled, the orbit comes out an hyperbola, and the
perihelion point is either in a tangent to the sun, or as nearly so as
physical circumstances will permit.

" I have the honour to be, &c,

'* Sears C. Walker."

2. Observations of the Comet. By Captain Tucker, R.N., Com-
mander of H. M. Ship Dublin. Communicated by the Lords Com-
missioners of the Admiralty.

The comet was first seen on the 3rd of March, and observations,
of which the following is a tabular statement, were made from the
4th to the 26th of March :—

Day and ship mean
time of observations,

Ship's
longitude.

d h m s
Mar. 4, 6 58 26106

7 4 28

0W,

5,7 0 57107 17

Ship's
latitude.

8 10S
11 2

Observed

altitude of

comet.

7 30

Distance of
comet from
known stars.

Names of

stars of

comparison.

Length
of tail.

72 44 ORigel

48 44 30Fomalhaut
f47 28 30!«Eridani
166 16 OJAldebaran

302

Royal Astronomical Society.

Day and ship mean
time of observations

Ship's
longitude.

Ship's
latitude.

Observed

altitude of

comet.

Distance of
comet from
known stars.

Names of

stars of

comparison.

Length
of tail.

d h m s

o /

o /

o /

f4°6 26 £

« Eridani

o /

Mar. 6,7 4 4S

107 59 W

14 IS

9 6

II 65 32 45
.} 85 59 0

Rigel
Sirius

[ 1.62 4 OJAldebaran

f61 56 15

Rigel

43 0

7,6 30 0108 22

16 44

6 5

{ 59 25 0
1 82 31 30

Aldebaran
Sirius

8,6 41 54107 31

18 21

16 32

/79 34 0
159 3 0

Sirius
Rigel

7 6 4

14 0

/79 33 0
I 56 44 30

Sirius
Aldebaran

9, 7 10 23

106 29

19 33

14 48

/76 39 15 Sirius
155 49 50 Rigel

f 73 45 0

Sirius

. 0, 6 52 15

106 17

20 41

18 30

< 52 28 50
1 46 17 0
[46 31 0

Rigel
a, Eridani
a, Eridani

11,7 1 35

105 25

22 4

18 12

< 71 2 0
150 11 50
f68 36 15

Sirius
Rigel
Sirius

12,7 15 10

105 16

24 1

18 0

J 47 14 45
| 46 31 15
146 57 0
f57 40 0

Rigel
Aldebaran
» Eridani
Sirius

17,7 8 15

96 44

30 45

20 0

J 35 36 30
| 36 49 0
149 3 0
f55 58 0
33 49 13

Rigel
Aldebaran
« Orionis

Sirius
Rigel

42 16

18,7 14 40

95 52

32 0

20 17

- 60 18 0

35 19 0

W7 0 30

(64 11 0

31 57 15

Canopus
Aldebaran
« Orionis
Sirius
Rigel

19,7 19 40

93 52

32 35

" 33 56 0

59 21 0

M5 20 45

f52 10 30

30 9 8

Aldebaran
Canopus
« Orionis
Sirius
Rigel

45 0

20,7 11 30

90 5

33 13

* 32 19 30

43 35 0

v-58 46 0

f49 31 30

Aldebaran
a. Orionis
Canopus
Sirius

22, 7 34 38

86 42

34 24

20 0

J 26 49 53
| 57 27 30
L30 3 0
f44 27 0
55 46 0

Rigel

Canopus

Aldebaran

Sirius

Canopus

36 26

26,7 15 57

82 40

32 2

23 30

{ 21 12 23 Rigel
26 24 30 Aldebaran
-34 19 53 * Orionis

'i

Royal Astronomical Society.

303

3. Observations of the Comet made at Auckland, New Zealand,
accompanied by a map of its progress amongst the stars. By John
Collyer Haile, Esq. Communicated by G. B. Airy, Esq.

The comet was first seen on the 2nd of March, and continued
visible till the 2nd of April. The following places of the comet are
annexed, which are deduced from observations made at Auckland,
though the method of observation is not mentioned, nor are any de-
tails given : —

1843.

Time.

Right ascen.

Declination S.

Length of tail.

h ra

h m s

o / /'

March 7

8 2

0 43 27

9 39 8

32 30

9

7 37

1 10 52

10 55 48

35 10

10

7 45

1 24 7

11 21 44

35 50

13

7 58

1 58 32

11 10 42

19

7 35

2 49 3

9 27 50

41 50

20

7 37

3 0 2

9 22 43

41 30

24

8 3

3 25 50

8 29 13

35 10

Long, of Auckland 1^4 45 40 East.
Lat. of ditto 36 51 0 South.

4. Notes on the Comet, extracted from the Journal of Captain
G. Rodney Mundy, R.N., Commander of H.M.S. Iris. Communi-
cated by G. B. Airy, Esq.

5. Extracts from a Daily Journal of Remarks and Observations on
the Comet, as seen at Van Diemen's Land. By Lieut. Kay, R.N.
Communicated by Lieut.- Colonel Sabine, R.A.

The tail of the comet was first seen on the 1st of March. The
nucleus was first seen on the 6th of March ; and on this evening the
observed length of the tail was 23° 20', being at its broadest part
about 54' in breadth ; the extreme breadth and the greatest conden-
sation of light occurring at a distance of 12° from the nucleus.

On the 7th, the tail was 26° in length and 50' in extreme breadth.
A dark line commencing near the middle and extending to the end
divided the tail into two portions.

On the 9th the length of the tail was 39° and its extreme breadth
76'. The dark line was again observed commencing at about the
middle of its length.

On the 11th the nucleus was well seen and examined with great
care. No stellar point was visible, but its appearance was that of a
large star covered with a thin film of cloud, or viewed through a
telescope which had not been adjusted to focus. The length of the
tail was 45°, and the extreme breadth 76'.

On the 12th a different telescope was employed for the examina-
tion of the nucleus, but no stellar point was visible. The length of
the tail was 42° and its breadth 80'.

On the 14th, 22nd, 24th and 27th, the observed length of the tail
was 42°, 40°, 39°, and 35° respectively.

"^he following table exhibits the distances from conspicuous stars
which were observed with the sextant : —

304,

Royal Astronomical Society.

Mar. 7

10

11

12

13

Mean solar
time

h m s

7 30 0

7 36 0

7 38 0

7 40 0

7 42 0

7 44 0

7 47 0

7 38 13
7 45 50
7 36 1
7 44 15

7 49 50

8 1 19
8 9 22
7 44 15

7 54 27

8 2 2
8 10 1
8 19 10
8 4 6

Observed
distance.

62

104

64

77

102

85

76

f 53

1 70

f 53

t 70

f 69

t 50

f 46

I 64

fl07

t 89

r 72

L 93

f 64

I 69

f 67

I 48

f 46

I 62
f 108

I 87

r 99

I 70

f 67

I 92

/ 43

1 64

Star of
comparison.

17 Aldebaran.
49 «2 Centauri

36Rigei.

31 « Orionis.
34Procyon.

9|Sirius.
43iCanopus.
24Aldebaran.
51 Canopus.
26 Aldebaran.
49Canopus.

9,Canopus.
28Aldebaran.
19 « Eridani.

a. Orionis.

a? Centauri

Procyon.

Sirius.

Castor.

a. Orionis.

Canopus.

Canopus.

Aldebaran.
36« Eridani.
18 a. Orionis.

»2 Centauri

Procyon.

/ Argus.

Sirius.

Canopus.
45PolIux.
41 Aldebaran.
49|Canopus.

Mar. 13

22

24

27

Mean solar
time.

ll m
8 12

20

8 21
8 22
8 26

7 25
7 40

7 56

8 5
8 13
8 20
7 51

7 58

8 3
8 8
8 13
7 45

7 56

8 1

20

34

10

Observed
distance.

f 47

t 56

43

65

81
97

r 57

\ 30

r 52

I 41

r 28

\103
/ 65
I 30

r 41
t 28
f 57
t 50
f 54
t 28
f 103
25
U
28
47
38
M
(12
55
25
5(5
20
97
44

Star of
comparison.

t

34 x Eridani.
58 ee Orionis.
49JRigeI.
15jSirius.
51lProcyon.
58;/ Argus.
38 Canopus.
52 Aldebaran.
44 L Eridani.
30 cc Orionis.

lRigel.
lliRegulus.
49jProcyon.
54Aldebaran.
28 « Orionis.

4]Rigel.
40Canopus.
27Sirius.
20 a. Eridani.
49' Aldebaran.
12Regulus.
1 lRigel.
12'Rigel.
51 (Aldebaran.
46 Sirius.
34 w Orionis.
22,t« Eridani.
51 Procyon.
40 Canopus.
49Aldebaran.

3 « Eridani.
59|Rigel.
32Regulus.

4Sirius.

6. Extract of a letter from A. Abbott, Esq., containing remarks
on the Comet as seen at Madeira, accompanied by two drawings.
Communicated by Sir John Herschel.

7. Observations of the Comet by Captain P. P. King, R.N., made
at Port Stephens, New South Wales. Communicated by Captain
Beaufort, R.N.

The tail of the comet was first seen at Port Stephens on the 2nd
of March, producing great alarm among the natives.

On the 3rd it was again seen, and a second ray was observed ex-
tending obliquely from it, and making with it an angle of 10°.

On the 4th, the nucleus was observed with an achromatic telescope
when about 8° above the horizon. It appeared like a reddish stellar
spot, the limbs well defined, and about 1' in diameter by estimation.
On this evening and the following, distances of the comet from
neighbouring stars were measured with the sextant.

Royal Astronomical Society. 305

On March 18th and following days, comparisons of the comet
with neighbouring stars were made with an annular micrometer at-
tached to an achromatic telescope, of which the following are the
most important : —

March 19, 7h 37m 14s sidereal time (mean of three observations),
the nucleus was east of ij Eridani 3m 53s* 22, and 7' 0" south of it.

March 20, 7h 36m 57s,5 sidereal time (mean of four observations),
the nucleus was east of ij Eridani 1 lm 16s,23, and 1 1' 39" north of it.

March 23, 7h 27m 6S,3 sidereal time (mean of three observations),
the nucleus was 4m 17s,2 east, and 9' 19" south of f Eridani.

March 29, 8h 26m 59s- 1 sidereal time (mean of three observations),
the nucleus was 12m 0S,28 west, and 15' 41" north of AEridani.

This paper was accompanied by a map showing the path of the
comet amongst the stars, and by drawings of its appearance on suc-
cessive nights.

8 to 14. Papers on the Comet, as seen in the Mauritius, in New
South Wales, in New Zealand, off the Island of Timor, at Batavia,
and in Texas; including Pen- drawings of its appearance by Mrs.
Grant.

15. Letter from the Rev. W. S. Mackay to Sir John Herschel,
dated Calcutta, June 10, 1843. Communicated by Sir John
Herschel.

The comet was first seen at Calcutta on the 5th of March, and
continued visible until April 3. Distances from bright stars were
observed, from which approximate right ascensions and declinations
have been deduced.

Mr. Mackay observes with respect to the star rj Argus, that " in
March last, it had become a star of a first magnitude, fully as
bright as Canopus, and in colour and size very much like Arcturus.
This has been observed by several other persons to whom I pointed
it out. Is the star known as a variable star, or is the change now
first observed ? a Crucis looked quite dim beside it."

With regard to the variability of y Argus Sir John Herschel re-
marks as follows : —

The sudden increase of tj Argus from a star intermediate between
the first and second magnitude, to a first-rate first magnitude,
which took place between 1837 and 1838, was mentioned by me in
a letter to Messrs. Beer and Madler, of which an extract is in No. 354
of Schumacher's Astronomische Nachrichten* . It was then far in-
ferior to Canopus, but equal to Arcturus, and very nearly, or quite
so, to a Centauri. It had diminished materially when I left the Cape
in April 1838, but was still a great star of the first magnitude. It
would appear to be now making another start forward. If this con-
tinue we may have a rival to Sirius, or perhaps to the planets. In
1838 its brightness was such as to obliterate many curious and in-
teresting details of the great nebula in its immediate proximity,
which I had fortunately recorded in its former state.

I do not quite understand Mr. Mackay's distinction between size
and brightness of a fixed star. Canopus is at least double of Arc-
[* See also Phil. Mag. S. 3. vol. xii. p. 521, 526.]
Phil. Mag. S. 3. Vol. 24. No. 1 59. April 1 844. X

306 Royal Astronomical Society.

turus in its quantity of light. Arcturus and a Centauri are nearly
equal, the latter, however, being somewhat the brighter of the
two.

I take this opportunity to mention, that I remain fully convinced
of the reality of the periodical variation of a Orionis. Not so of
a Cassiopeia?, in the case of which star the amount of supposed change,
however, was very much less considerable, and in which, on account
of its difference of colour from y, the compared star, the moon affects
the comparison, when above the horizon*.

16 Observations of the Comet made in March 1843, at the Mau-
ritius. By W. Lloyd, Esq.

The comet was first seen on the 1st of March, and its nucleus
was seen by Mr. Lloyd on the 3rd. On the 4th, instruments were
set up at Doguet, on Les Plaines Willhems, and observations were
commenced. These consist chiefly of observations of altitudes and
azimuths, the details of which are given. The comet was observed
till the 22nd of March.

III. Occultations observed at Ashurst in the year 1843, by R.
Snow, Esq. ; for which we refer to the Monthly Notices.

IV. Right Ascensions and North Polar Distances of the Comet of
Mauvais observed at Hamburg. By C. Rumker, Esq. Communi-
cated in a letter to F. Baily, Esq., dated July 25, 1843. These will
also be found in the Monthly Notices.

In a letter to Dr. Lee, dated August 18, 1843, additional places
of the comet were communicated.

From the former of these sets of observations, M. Gotze calcu-
lated the following elements of the orbit of the comet : —

Perihelion passage, 1843, May 690816 Greenwich mean time.

Longitude of ascending node... 157 13 23*72 \ From mean equinox

Longitude of perihelion 281 50 58*99 J of June 20, 1843.

Inclination 52 53 294

Log. perihelion distance 0-2097314 Motion direct.

V. On the Divisions of the Exterior Ring of the Planet Saturn.
By the Rev. W. R. Dawes.

The existing evidence relating to a division of the outer ring of
the planet Saturn, into two or more concentric rings, is of a very
conflicting character. A few observers have been well satisfied that
they have occasionally perceived such a division, among whom stand
conspicuous, Short, the celebrated maker of reflecting telescopes,
Professor Quetelet, of Brussels, and Captain Kater, whose paper on
the subject, published in vol. iv. part 2 of the Memoirs of the Astro-
nomical Societyf, discusses the subject at some length, in addition
to a detail of his own observations. The evidence on the other side
of the question, however, though of a negative character, has always
appeared to me so strong, that I must confess myself to have been
somewhat incredulous of the supposed fact of any subdivisions ex-

[* See Phil. Mag. S. 3. vol. xiv. p. 528; vol. xvii. p. 310, 311.]
[f An abstract of Captain Kater's paper will be found in Phil. Mag.,
S. 2. vol. viii. p. 456.]

. Royal Astronomical Society. 307

isting. This circumstance increases my inclination to put on record
a recent observation of a peculiarly satisfactory kind.

September 7, 1843. — At Mr. Lassell's observatory, Starfield, near
Liverpool. The day had been cloudless and remarkably warm, the
maximum of the thermometer being 76° where all precautions had
been taken to keep it as cool as possible. In the evening the sky
was hazy and the stars dull. At about 9 p.m. Mr. Lassell turned
his equatorially mounted 9-foot Newtonian reflector, of 9 inches
aperture, upon Saturn, with a power of 200, and was electrified at
the beautifully sharp and distinct view of the planet presented to
him. Having applied as an eye-piece an achromatic lens (being the
object-glass of a microscope), which produced a power of 450 times,
Mr. Lassell examined the planet for a few minutes. I then took my
place at the telescope, and Mr. Lassell requested me to examine care-
fully the extremities of the ring, and say if I observed anything re-
markable. Having obtained a fine adjustment of the focus, I pre-
sently perceived the outer ring to be divided into two. This per-
fectly coincided with the impression Mr. Lassell had previously re-
ceived. For some minutes I scrutinized this interesting object, and
occasionally, for several seconds together, had by far the finest view
of Saturn that I was ever favoured with. The outline of the planet
was very hard and sharply defined with power 450 ; and the primary
division of the ring very black and steadily seen all round the south-
ern side. When this was most satisfactorily observed, a dark line was
pretty obvious on the outer ring. I was not only perfectly satisfied
of its existence, but had time during the best views carefully to es-
timate its breadth, in comparison with that of the division ordinarily
seen. The proportion appeared to me to be as one to three ; but
Mr. Lassell estimated it at scarcely one-third. It is certainly rather
outside the middle of the outer ring, and is broadest at the major axis,
being in this respect precisely similar to the primary division. It
was equally visible at both ends of the ring.

For further satisfaction other eye-pieces were tried. A positive
double eye-tube, magnifying 400 times, came nearest to the achro-
matic lens in efficiency ; yet the latter gave the impression of equal
sharpness and light, with an increase of 50 in the power. With
400 the secondary division was perceptible during occasional best
views of the planet ; but no lower power displayed it at all, though
with them the usual features of Saturn were splendidly distinct. A
positive double eye-piece producing a power of 520 was also applied,
but by this time the state of the air had deteriorated ; and though
some confirmatory glimpses were obtained, the view was not so good
as with the achromatic lens.

Neither Mr. Lassell nor myself obtained a single glimpse of any
further subdivisions of the ring. The shading of the interior edge
of the inner ring was very obvious, but no dark line was even sus-
pected in that situation.

From my description of this splendid telescopic view of Saturn,
it will be seen that it was very similar to that depicted by Captain
Kater, in fig. 3 of his drawings of the planet, in vol. iv. part I of the

X2

308 Geological Society. Mr. F. W. Simms on a Section of

Memoirs ; except that, in his plate, the outer ring is much too broad
in proportion ; and also that his subdivision bisects the outer ring.
Moreover, the ring is now more obliquely seen than in 1825, and
the northern side of it is in view. It is difficult to suppress the un-
availing regret that the planet was not, as in that year, at an altitude
of about 60°, instead of only 14°; and that the atmosphere of this
country is so rarely in a state to do justice to the capabilities of our
most powerful and perfect instruments.

It may be proper to remark, that a record of our observations was
entered in Mr. Lassell's journal, both by him and myself, from which
the above account has been compiled.

November 8, 1843. W. R. Dawes.

GEOLOGICAL SOCIETY.
[Continued from p. 232.]

June 7, 1843 (continued). — A paper was read, entitled "Account
of a Section of the Strata between the Chalk and the Wealden Clay
in the vicinity of Hythe, Kent." By F. W. Simms, Esq., F.G.S.

The section here described begins on the top of Tolsford Hill, the
summit of the chalk escarpment, about 600 feet above the sea at low
water, and about two miles immediately north of Hythe. It strikes
nearly due south, passing very near to Saltwood Castle, and close to
the church at Hythe, and reaches the sea beyond the low ground on
the south of that town. This line cuts the strata, which successively
rise towards the south from beneath the chalk, nearly at right angles.

The author, in directing the works of the South-Eastern (Dover)
Railway, had caused borings to be made, with a view to the con-
struction of one of the principal tunnels on the main line of road, at
Saltwood. He afterwards extended his researches upward, for the
purpose of illustrating the stratification ; and ultimately sank a
shaft, from the bottom of the quarries at Hythe, down to the Weald
clay. The account of these operations is illustrated by large sectional
drawings, without the aid of which it is difficult to convey a distinct
notion of them ; but the following summary includes some of the
most important results.

§ The division of the subcretaceous series adopted by the author is
that proposed in the Geol. Trans., 2nd ser. vol. iv. pp. 105-115 ;
and his object was to ascertain the thickness, inclination, and general
character of the successive groups, in a descending order. He found,
however, unexpected difficulty in tracing the different strata to their
outcrop, from the interference of ruins fallen from above, and still
remaining even on the faces of the escarpments. Thus the top of
the Gault was obscured by a mass of subsided chalk, which, if the
measure had been taken on the surface, would have caused an error
in the thickness of more than 44 feet ; the upper division of the
lower greensand would have given 41 feet in excess ; the middle bed
would have been diminished by nearly the same amount ; " and the
whole of the clay beds between the quarry-rock and the Wealden
would altogether have escaped notice, as they are covered by the

the Strata betwee7i the Chalk and Wealden near Hythc. 309

ruins of the superior beds, and their existence was until now un-
known." The author therefore could not attain his purpose without
having recourse to boring and levelling ; the mode of conducting
which processes, and the calculations connected with them, he has
explained.

1 . The upper greensand was found to be entirely wanting on the
principal line of the section, the only trace of it being some grains
of sand mixed with chalk-marl over the gault. A second boring,
about half a mile eastward of the principal line, gave the same
negative result ; but at Folkstone Cliff, six miles distant, there is,
in a corresponding place, a true greensand, 15 feet thick, indurated
to the condition of stone, with much pyrites, and passing gradually
upwards into the chalk-marl through a thickness of 17 feet more.
The junction between the upper greensand and the top of the gault
below is decided and abrupt.

2. The borings through the Gault, at its lower part, were unat-
tended with difficulty, and the limit between it and the lower green-
sand was very well defined.

3. Lower greensand. — a. The uppermost division of this group,
rising and running out beyond the bottom of gault, disclosed a sur-
face inclined at the same angle, and continuous with that beneath
the clay, which appeared to have been removed by denudation. The
beds of this upper division are enumerated in detail, and the places
of some of the fossils specified.

b. The Saltwood tunnel being driven directly through the upper
part of the middle division of the lower greensand, this portion of the
series became an object of great interest to the author, and is fully
described. In one boring, after ten feet of somewhat sandy yellow
clay, came a very dark green, tough and adhesive mass, almost black
when first brought to the surface, and containing very little sand.
This, which the author calls clay, he considers as the chief character-
istic of the middle division. At a depth of 53 feet sand was mixed
with it ; and at 56 feet a " rock" of limestone was reached, which the
author regards as commencing the next lower division of this group.

c. The thickness of the third (or " quarry-stone ") division of the
lower greensand was ascertained by combining the results of several
different borings. At this period the author was induced, by a com-
munication with Dr. Fitton, to change the boring for a shaft, in
order to bring up more extensively, and to preserve, the fossils of the
unknown strata between the quarries and the Weald clay. This
shaft was 5 feet by 4 in dimensions, and it was found necessary to
support it throughout with timber. The strata thus cut through may
be considered, in a general view, as consisting of clay, which was
found to be 49 ft. 6 in. thick : and the bottom of this clay was sepa-
rated from the uppermost beds of the Wealden, containing the usual
freshwater fossils, by a layer of soft sand only one inch in thick-
ness.

§ The measures of the several groups between the chalk and the
Weald clay, thus ultimately obtained, were as follows ; the general
dip being due north, at an angle of about 1° 19'.

U06 6

310 Geological Society: Dr. Fitton on the

Upper greensand; — on the principal line of section, wanting, ft. in,

[At Folkstone cliff 15 0

Gault 126 0

Lower greensand : — ft- in#"

Upper division 70 0

Middle division 158 0

Quarry-stone, &c. ft. in.

Sand above the quarries 67 0

Quarry " rock " 48 0 }>178 6

Sand and stone previously concealed 14 0
Clay beneath the sand and stone. . 49 6 J
Total thickness from the chalk to the Wealden. . . , . . 547 6
§. The lowest sand and stone, occupying 14 feet beneath the
quarry-" rock", are stated by the author to contain the same fossils
as the calcareous beds above.

The clay beneath the sand and stone appeared to consist of two
principal portions : — the upper, about 34 ft. 6 in. thick, composed
chiefly of a sandy greenish-grey clay, which in some places had the
properties of fuller's earth ; in this were two thin beds of brown sandy
clay, and of clay indurated to the condition of soft stone.

The lower part of the clay, about 10 ft. 6 in. thick, was greenish-
brown, apparently containing more fuller's earth, and becoming
darker and more argillaceous as it descended ; at 2 ft. 6 in. from the
top of this division was a bed, more marly than fuller's earth, and two
feet thick, which contained a greater number of fossils.

§. The fossils from this clay, which had been placed apart, and
numbered during the sinking, occurred in the following order, be-
ginning at the top : —

ft. in. ft. in.

0 0 to 25 6. Plicatula, Pecten obliquus (interstriatus) , Phola-
domya, n.s. ?, Area Raulini, Terebratula, Pleuro-
tomaria gigantea.

31 6 to 34 6. Plicatula, Area Raulini, Pholadomya acuticostata},
Perna Mulleti.

37 0 to 39 0. Corbula, and Pinna, numerous; with a Mytilus.

39 0 to 49 6, Corbula, Lima, two species ; Nucula, Pinna, Teredo,
— the bottom of Cypricardia ?, Venus ?, Ammonites Deshayesii ?.

this clay.
Beneath was the Wealden clay, with Cyclas, small Ostrea and Paludina.

§. Subjoined to the principal section, are sectional drawings of the
Saltwood tunnel, and of a trial shaft sunk near it, illustrating parti-
cularly the junction of the upper and middle groups of the lower
greensand. The summit of the tunnel is a few feet above the top
of the middle group, and there was a constant discharge of water
along the line junction, in such quantity as to cause great difficulty
in its construction. This middle division, near its upper part,
afforded some fine specimens of fossils, chiefly in ferruginous con-
cretions, among which is Nautilus radiatus, with fossil coniferous
wood eroded by a Gastrochanu. Another remarkable product was
a new and beautiful fossil resin, found about 10 feet below the junc-

Lower Greenland of Kent and the Isle of Wight. 311

tion above-mentioned. A statement of a chemical examination of
this substance by Mr. Edward Solly is here given in full : it partakes
of the properties of amber and of retin-asphalt, and is principally
marked by its clear red colour, its infusibility, and the difficulty with
which it is acted upon by many chemical solvents.

" Comparative remarks on the Lower Greensand of Kent and the
Isle of Wight." By Wm. Henry Fitton, M.D., &c.

§ . The author having, since the last meeting of the Society, seen
the result of the operations at Hythe described by Mr. Simms in the
preceding paper, — and subsequently examined one of the principal
quarries at Maidstone, belonging to Mr. Bensted, here *nentions, on
the authority of the latter gentleman, some facts which indicate a re-
semblance between the lower part of the section there and at Hythe.
In sinking a well about six years ago (1837), at Barming Heath, on
the south-west of Maidstone, Mr. Bensted found the whole thick-
ness of the stone and hassock (after passing through about 20 feet

of loose stone and red clay), to be about 130 feet.

Immediately below was dark greensand, including a Venus, Gervillia,

Ammonites, and other fossils, about 10 feet Total 140 feet.

And finally clay, " not that of the Wealden," about 30 feet:

— at which depth the sinking was discontinued,
Mr. Simms's section gives for the total thickness of the calcareous
quarry-stone and hassock, at Hythe, 115 feet; beneath is sand
and stone, supposed to belong to the calcareous group, 14 feet.

Total 129 feet.
And then, down to the Wealden, a succession of clays which include
peculiar marine fossils, amounting to 49 feet 6 inches ; exceeding the
thickness of the clay sunk into beneath the quarry- stone at Barming
Heath by about 30 feet,

The sinking therefore near Maidstone accords, so far as it goes,
with that of Hythe, in exhibiting a considerable thickness of marine
clay between the quarry-stone and the Wealden.

§. The author remarked, in passing from the railway at Paddock
Wood to Maidstone, through Nettlestead and Wateringbury, that a
tract of very irregular heights projects beyond the line which he had
coloured as greensand ; and extends from East Peckham towards Lo-
dington, in some places to more than a mile beyond what seems to
be the plateau of the Kentish rag. Mr. Bensted has since informed
him that, near Wateringbury, a bank of blue clay crops out, above the
Wealden and below the greensand. This region therefore offers
a point for inquiry ; and there is great probability of its affording
sections of this lower clay.

§. An examination of the fossils, and of the substances which in-
clude them, brought up from the shaft sunk by Mr. Simms beneath
the lowest stone-beds at Hythe, leaves no doubt of the very strong
resemblance of this part of the Kentish series, to that which has
been described at Atherfield in the Isle of Wight. The principal
difference between the lowest clay at the two places, consists in the
absence, at Hythe, of any bed of stone, like that at the bottom of
the Atherfield section, which abounds so very remarkably in fossils.
§. Although the section of the lower greensand on the Kentish

S 1 2 Geological Society.

coast is more full and complete than that between Blackgang Chine
and Atherfield, the latter has the great advantage of being perfectly
disclosed and continuous, from the top to the bottom, so that the
whole succession can be readily examined in detail : while it is
evident, from the perfect conformity of the beds and their general
consistency of character, that their deposition was not only unin-
terrupted by stratigraphical disturbance, but probably unaccompa-
nied by any great change in the conditions of the fluid by which
they were deposited.

§. The absence, in the Isle of Wight, of limestone resembling that
of the Kentish quarries, which is the chief point of contrast between
the sections there and in Kent, is deserving of great attention. The
rag, though very unequally distributed (as is not unusual with beds
which have so much of a concretional character), extends without
material interruption from the Kentish coast to the neighbourhood
of Godstone ; its greatest expansion being at Maidstone, where the
thickness exceeds 1 20 feet ; while Mr. Simms's section proves that
the Hythe quarries are nearly of equal thickness. The decrease,
therefore, in the proportion of calcareous matter, in receding from
what may be called this central region of the limestone, — either
inland, through Surrey and Hampshire, or westward, by the coast
of Sussex to the Isle of Wight and Dorsetshire, is very rapid ; and
is the more deserving of notice in the Isle of Wight, as the total
thickness of the lower greensand (both near Shanklin, on the east,
and westward from Blackgang Chine to Atherfield), cannot be less
than 400 feet, — the thickness of the groups below the gault at Hythe,
according to Mr. Simms.

This reduction of the calcareous matter between Maidstone and
Surrey is the more remarkable, as the sands throughout that in-
terval are absolutely continuous : the distance from Maidstone to
Redhills, where there is no appearance of limestone, being only 30
miles ; that between the central limestone at Hythe and Atherfield
being about 115 miles. The equivalent of these calcareous beds
must be sought for in Surrey and Hampshire, in those ranges of
concretional stone which are there distributed irregularly, but in a
somewhat stratigraphical arrangement, through the lower green-
sand ; as in the " Bargate stone ; " the chert of Leith Hill, &c. ; and
generally, the sands of all that region ought to be examined atten-
tively, with a view to their comparison with the cliffs between Black-
gang Chine and Atherfield.

§. The separation of the lower greensand from the other subcre-
taceous groups, was founded on its obvious stratigraphical distinc-
tion, from the Gault on the one hand, and from the subjacent Weal-
den on the other : and the subdivisions were derived, from the pro-
minence of certain natural features of the surface, evidently corre-
sponding to the composition and succession of the strata. The ex-
pediency of these subdivisions in the coast section at Hythe appears
to be confirmed by Mr. Simms's survey ; his section, when reduced
to the natural scale of height and distance, showing that the features
of the country agree M'ith the division of the strata between the
gault and the bottom of the calcareous beds into three groups : and

Intelligence and Miscellaneous Articles.

313

if the clav newly discovered beneath the quarries be added to the
series, it will form another subdivision, accordant with the principle
of arrangement above mentioned. The chief question remaining
with respect to this lowest group of marine clay is, whether it will
be necessary to detach it altogether from the other divisions of the
lower greensand ; and this cannot be decided without a deliberate re-
view of the subcretaceous fossils, — and of the strata which afford
them.

XLVII. Intelligence and Miscellaneous Articles.

EXPERIMENTS ON COFFEE.

To the Editors of the Philosophical Magazine and Journal.
Gentlemen,
fTlHE object of the present communication has reference to some
J_ experiments on coffee which I think possess some novelty, if
they have no other merit. It is well known that this article during the
process of roasting loses from 19 to 25 per cent, of its weight, this
is principally water evaporated at the very high temperature it is ex-
posed to. I speculated that if this moisture could be previously
withdrawn, without the application of heat, a much shorter exposure
to a high temperature would afterwards be required to complete the
process, and that an equivalent improvement in the quality might be
looked for.

To test this I accurately weighed two packages of the same Ja-
maica coffee, each containing 8 ounces ; one package, made up in
paper, I inclosed in a jar with a very close cover, containing a quan-
tity of fresh-burned quicklime ; the second package I kept by me ;
I anticipated that the lime would attract the moisture from the in-
closed air, and that the air would in its turn take the moisture from
the coffee. After two months I opened the jar ; the coffee did not
appear shrunk, and was but very slightly altered in colour, but on
weighing it I found it reduced to 6£ oz., thus showing a loss of nearly
15 per cent. I separately roasted the two samples; the one I had
kept by me still weighed 8 oz. ; it took the usual time, and when
weighed was 6£ oz. ; the second sample had scarcely been raised to
the required temperature when it suddenly swelled, and the process
was complete in much less than one third the usual time ; when
weighed it was 6| oz. The following Table will give a synopsis ;
No. 1 is the coffee that was treated with lime : —

No.

Weight before desiccation.

Weight after desiccation.

Weight when roasted.

1.

2.

8 ounces
8 ...

6*875 ounces.

6*625 ounces.
6-5

It will be observed that the sample No. 1 weighed more after
roasting than No. 2. Part of this increase might have been caused
by the latter being a little more highly roasted, but I am confident
that this would not account for so great a difference in so small a
quantity. The two samples were now ground and prepared in the

314 Intelligence and Miscellaneous Articles.

usual manner ; the quality of No. 1 was much better than the other,
being stronger, more aromatic, and finer in flavour.

Cork, February 27, 1844. Jas. J. Cunningham.

A NEW PROCESS FOR PREPARING GALLIC ACID. BY EDWARD

N. KENT.

During a recent examination of black ink, which had been pre-
pared by exposure to the atmosphere for three months, I found it
contained a quantity of free gallic acid, protosulphate of iron and
pertannate of iron.

Having previously experienced the inconvenience of waiting two
months to prepare gallic acid by the old process, and as it is not an
article of commerce, it; occurred to me that if the acid in the ink
could be easily isolated, it would form a valuable process for its
preparation when wanted for immediate use, as ink can always be
readily obtained containing the acid ready formed. I therefore
agitated a pint of ink with an equal measure of sulphuric aether*,
left it at rest for a few moments to separate, and then decanted the
aether, and found it had taken up gallic acid to the exclusion of the
other constituents, except a light vellow colour and odour of cloves,
these having been put into the ink. I then distilled the aethereal
solution nearly to dryness ; the residue crystallized on cooling.
I returned the distilled eether on the ink, and repeated the process
the third time ; and after crystallizing three times and drying, ob-
tained 28 grs. of colourless gallic acid.

I then distilled off from the ink a little remaining aether, and the
ink was left as good for ordinary purposes as before ; and the only
expense in the preparation of the acid was the loss by evaporation
of about 1 oz. of the aether.

Most of the inks which I have tried gave the same result when
treated with aether. Some however which have been prepared by
boiling the nutgalls, and exposure for a few days only, yielded prin-
cipally tannic acid. It is therefore advisable to test the ink with
gelatine before attempting to prepare gallic acid by this process. —
Silliman's Journal for Jan. 1844.

ANALYSIS OF MELILITE. BY MONS. A. DAMOUR.

The melilite of Capo-di-Bove, which has been long known to mi-
neralogists, has hitherto been classed in most collections among
substances, the composition of which is not well known. The ana-
lysis by M. Carpe, performed several years ago, leaving much uncer-
tainty as to the nature of this mineral, M. Damour has undertaken
an analysis of some pure crystals recently received from Italy.

Physical characters — The colour of this substance varies from pale
honey-yellow to deep brown. Semitransparent. Fracture vitreous,
but no distinct cleavage. The crystals are strongly imbedded in the
matrix, and they rarely exceed 12-100dths of an inch in diameter;

* Mr. Silliman, Jun. states that he has repeated Mr. Kent's experiment suc-
cessfully. He observes that care must be had that the ajther is quite free from
alcohol, which commercial aether never is. As gallic acid is more soluble in alcohol
than in aether, the process is only partially successful when alcohol is present.

Intelligence and Miscellaneous Articles. 315

their form is a square prism, and often the regular octagonal prism.
It scratches glass feebly. Specific gravity 2'95.

Chemical characters. — When heated in a tube no water is ob-
tained. By the blowpipe becomes a pale yellowish glass, if the
crystals be slightly coloured, but a black glass if brown crystals be
used. This glass is sometimes attracted by the magnet, but this
property is not constant with all of the products. When fused with
borax on a small white cupel, melilite dissolves entirely ; if a little
nitre be added the fused matter has a brown colour while it is hot,
but on cooling it assumes a slight rose tint, indicating the presence
of manganese ; this the pale crystals do not exhibit. Salt of phos-
phorus dissolves it partially, leaving a skeleton of silica. Hydro-
chloric acid dissolves it readily, gelatinizing, and becoming of a
yellow brown colour.

By some preliminary trials M. Damour ascertained that melilite is
composed of silica, alumina, peroxide of iron, with a considerable
quantity of lime, a little magnesia, potash, soda, and traces of oxide
of manganese.

To discover the state of oxidizement of the iron, sodio- chloride of
gold was added to the hydrochloric solution of the mineral, placed
at the bottom of a bottle, hermetically sealed, and previously filled
with carbonic acid gas ; no trace of reduced gold was perceptible,
whence it was concluded that the iron was in the state of peroxide,
a conclusion which was strengthened by also employing the method
described by Berthier in the second volume of the Annates des Mines,
1842. M. Damour tried in vain to detect the titanic acid mentioned
by M. Carpe.

For the two analyses which M. Damour made of this substance,
crystals were selected which were well separated from the gangue ;
but they contained small grains of pyroxene, and other matters, which
resisted the action of hydrochloric acid.

Quantitative analysis. — The mineral reduced to coarse powder and
dried was acted upon by hydrochloric acid. The silica, separated
by the usual processes and weighed, was afterwards treated with a
solution of potash, to separate the insoluble matters ; in each opera-
tion there remained about 4 per cent, of small crystalline grains,
which was deducted from the total weight of the substance employed,
and from that of the silica.

The acid solution containing the bases separated from the silica
was neutralized by ammonia ; peroxide of iron and alumina were
precipitated, carrying down a little lime and magnesia ; these oxides
after washing and calcining were weighed. In order to separate the
peroxide of iron from the alumina, they were digested in hydro-
chloric acid ; the greater portion of the oxide of iron was dissolved,
but there remained a yellowish insoluble powder, greatly resembling
impure titanic acid, and this was fused with bisulphate of soda ; the
fused mass was entirely dissolved by boiling water, and the solution
was added to the hydrochloric solution containing peroxide of iron ;
by means of excess of potash the alumina was separated from the
peroxide of iron ; the alkaline solution, separated from the precipi-
tated peroxide of iron, was supersaturated with hydrochloric acid,

316 Intelligence and Miscellaneous Articles.

and the alumina, precipitated by carbonate of ammonia, was dried
and weighed, and its nature was further determined by the fine blue
colour which it gave with nitrate of cobalt.

The oxide of iron separated from the alumina still retained an ap-
preciable quantity of lime and magnesia, which were separated by
means of hydrosulphate of ammonia.

There remained to ascertain the substances contained in the am-
moniacal solution separated from the oxide of iron and the alumina ;
the liquor was treated with excess of oxalate of ammonia, which
gave a considerable quantity of oxalate of lime. This salt was col-
lected on a filter, dried, heated to redness, and the carbonate of lime
resulting was converted into sulphate, from the weight of which
that of the lime was deduced.

The liquor separated from the oxalate of lime was evaporated to
dryness, and the saline residue heated to low redness to volatilize the
ammoniacal salts. The fixed residue was dissolved in sulphuric acid,
the solution evaporated, and the salts deprived of water, heated to
redness and weighed ; they consisted of sulphate of magnesia, soda
and potash.

These different salts were decomposed by acetate of barytes, and
the magnesia was separated from the alkalies by the usual method ;
the potash and soda were estimated together in the state of sulphate,
and the potash afterwards separated by means of chloride of platina.
The analyses yielded as under : — (1) pale yellow crystals, (2) brown
crystals. (1) (2)

Silica 39-27 38-34

Lime 32-47 32-05

Magnesia 6*44 6*71

Potash 1-46 1-51

Soda 1-95 2-12

Peroxide of iron 10' 17 10-02

Alumina 6*42 8-61

Oxide of manganese traces

98-18 99-36

M. Damour attributes the slight differences of these analyses to
accidental admixtures in the crystals employed, and he represents
melilite by the formula

(Al, Fe) Si + 2 (Ca, Mg, K, N)s Si.

Ann. de Chim. et de Phys., Janvier 1844.

DESCRIPTION AND ANALYSIS OF HUMBOLDTILITE, AND IDEN-
TITY WITH MELILITE. BY MONS. A. DAMOUR.
This mineral is found in crystalline masses among the blocks of
Somma ; it is usually covered with a slight earthy calcareous coating,
which dilute acids readily remove. Small black crystals of pyroxene
frequently accompany and traverse it. Its physical properties are
perfectly similar to those of melilite. Its colour is generally very
pale. Fracture vitreous. Scratches glass with difficulty. Specific
gravity 2*9. The crystals are larger than those of the melilite of
Capo-di-Bove. Traces of cleavage parallel to the base are discover-
able. The form of the crystal is a square prism.

Intelligence and Miscellaneous Articles • 317

The chemical characters of this mineral also agree entirely with
those of melilite, with this only difference, that the presence of iron
is less strongly marked ; but it possesses the same degree of fusibi-
lity before the blowpipe, the same easy decomposition by cold hy-
drochloric acid, and in forming a jelly, and lastly the same consti-
tuent principles.

By analysis M. Damour obtained the following results : —

Silica 40-69

Lime 31'81

Magnesia 5*75

Potash 0-36

Soda 4-43

Alumina 10*88

Peroxide of iron . . 4*43
98-35
M. Damour observes, that in this analysis there occurs the same
relation as in that of the melilite, between the quantities of the
bases and the silica. It is, however, to be observed that the propor-
tion of peroxide of iron is much smaller than that of the alumina,
and that the reverse occurs in melilite ; but as the isomorphism of
peroxide of iron and alumina is well known, they may be substituted
for each other without changing the relations between the parts of
a compound to which they belong ; many minerals, and especially
garnets, offer numerous examples of this fact.

It is further remarked by M. Damour, that his analysis of this mi-
neral agrees almost entirely with that of M. Kobell {Annates des
Mines, tome v. 1834), but they differ in one estimating the iron in
the state of protoxide, and the other in that of peroxide. M. Da-
mour, adopting the latter opinion, considers that the same formula
may be given for melilite and humboldtilite, and proposes to reject
the former name. — Ann. de Ch. et de Phys., Janvier 1844.

ANALYSIS OF GUANO. BY MM. J. GIRARDIN AND BIDARD.

This analysis was undertaken by the desire of the Agricultural
Society of Rouen, and the specimen appears to have been furnished
by the Society.

It was mechanically separable into two distinct parts : one of
which was a brown moist powder containing a great quantity of car-
bonate of ammonia, and the other consisted of small white gravelly
pieces, which were somewhat hard, which differed only from the pre-
ceding powder in not containing any carbonate of ammonia ; this
latter portion was submitted to analysis and was found to contain
the following substances : —

Urate of ammonia. Phosphate of lime.

Oxalate of ammonia. ... ... magnesia.

potash. Sulphate of potash,

lime. Chloride of potassium, ^ very little.

Phosphate of ammonia. Fatty matter,
potash.

318 Intelligence and Miscellaneous Articles.

This analysis differs considerably from that of Fourcroy and Vau-
quelin, made in 1804, and from the more recent one of M. Wohler.
The above composition of guano is at any rate almost identical with
that of the excrement of aquatic birds and of poultry, and it throws
great light on the origin of this substance. It is evidently the excre-
mentitious product of birds, but according to the observations of M.
de Humboldt, the Ardea and the Phcenicoptera, which inhabit the
South Sea Islands, could not produce such great masses of guano
as those which exist in these islands ; it is evident, in the opinion of
MM. Girardin and Bidard, that guano does not belong to the pre-
sent system, but is a coprolite or fossil excrement of antediluvian
animals.

The presence of carbonate of ammonia in the fine powder is en-
tirely accidental. It is probably the result of the decomposition of
the urate of ammonia, which readily occurs by exposure to atmo-
spheric moisture.

This opinion is strengthened by the fact, that the gravelly sub-
stance, when exposed to the air, breaks up and falls to powder,
containing much carbonate of ammonia, which may be isolated and
sublimed by a gentle heat. Of all the principles which guano con-
tains, the uric acid and the ammonia are unquestionably of the great-
est importance ; it is to their abundance that the marked fertilizing
power of this valuable substance is to be attributed.

If, as can scarcely be doubted, the value of manures depends
greatly upon the quantity of azote which they contain, and if the
rapidity of their action upon vegetation is in direct proportion to the
facility with which they yield their soluble or gasefiable principles
to plants, it is easy to comprehend the superiority of guano over
the greater number of manures, and the quickness with which it acts.
It is absolutely in the same condition as pigeons' dung, the chemical
nature of which is identical, except a smaller proportion of ammo-
niacal compounds.

In order to determine the value of guano as a manure, the authors
determined, with the greatest care, the quantity of uric acid and am-
monia which it contained; and the analysis showed that 100 parts
of it contained

Dry uric acid 18'4 representing 6*13 of azote

Ammonia 130 ... 10'73 ...

Consequently 100 of guano represent. . 16*86
The proportions of uric acid and ammonia in guano may vary ac-
cording to the degree of alteration which it has undergone, convert-
ing a portion of urate into carbonate of ammonia, the volatility of
which facilitates its continual loss. This is the only way in which
the considerable differences can be explained, which exist, the authors
observe, as to the azote, in their results and those of MM. Boussin-
gault and Payen, who, in fact, found only 4*97 per cent, of azote in
rough guano and 5*39 per cent, in the separated and sifted powder,
so that while MM. Boussingault and Payen give 7 '41 as the equiva-
lent of guano, MM. Girardin and Bidard give 2"37. — Ann. de Ch. et
de Phys., Janvier 1844.

Meteorological Observations. 319

ANALYSIS OF PECTIC ACID. BY M. FROMBERG.

After numerous analytical researches, the author has adopted the
following as the composition of pectic acid : —

Calculated.

C>2 45-48

H>6 4-95

O10 49-57

100-
M. Fromberg is of opinion that the quantities of carbon found by
MM. Fremy and Regnault are too small, and that the formula
C24 H34 O22 deduced from their analysis is not correct.

The author's researches have, however, in general confirmed the
observation of M. Fremy relative to the alterations that pectic acid
undergoes by ebullition with water. He has more than once ob-
served, that after long boiling with a weakly alkaline liquor, no pre-
cipitate is formed by the addition of an acid ; metapectic acid was
produced, which is soluble in acids. — Journ. de Ph. et de Ch., Fev.
1844. '_

METEOROLOGICAL OBSERVATIONS FOR FEBRUARY 1844.

Chiswick. — February 1. Frosty: very clear and dry: frosty. 2. Snowing :
frosty at night. 3. Frosty : clear, with bright sun : overcast and frosty. 4. Snow
in broad flakes: densely clouded and rapid thaw at night. 5. Frosty: clear:
severe frost. 6. Sharp frost : clear and fine: overcast. 7. Hazy, with slight rain :
overcast : heavy and continued rain in the evening. 8. Frosty: very clear : frosty.
9. Frosty, lightly clouded: densely overcast. 10. Cloudy. 11. Slight rain.
12. Uniformly overcast : clear and fine : foggy and frosty. 13. Frosty, with
dense fog : frosty, with fog at night. 14. Thick hoar-frost : clearing : overcast.
15. Slightly overcast and fine: hazy, with rain. 16. Clear and fine. 17. Over-
cast: clear. 18. Cloudy : slight rain at night. 19. Densely clouded : clear and
windy. 20. Clear and frosty : fine : clear, with sharp frost at night. 21. Snow-
ing in broad flakes : sleet and rain : hazy. 22. Snowing : clear and frosty. 23.
Sharp frost: overcast: heavy rain from six till nine p.m. 24. Clear : cloudy :
clear and frosty. 25. Rain : squally : cloudy and tine. 26. Heavy clouds and
showers : stormy, with rain at night. 27. Clear, cold and dry. 28. Clear and
cold: fine, with sun: cloudy. 29. Very fine : rain. — Mean temperature of the
month 3*59° below the average.

Boston. — Feb. 1. Fine. 2. Cloudy: snow early a.m. 3. Fine. 4. Snow.
5,6. Fine. 7. Rain : rain early a.m. 8. Fine : rain early a.m. 9. Fine. 10.
Fine: snow a.m. 11. Snow : snow early a.m. 12. Fine. 13—15. Cloudy.
16,17. Fine. 18. Fine: rain p.m. 19. Cloudy: rain a.m. 20. Fine. 21.
Cloudy: snow p.m. 22. Cloudy. 23. Cloudy: snow early a.m. : snow p.m.
24. Stormy : snow p.m. 25. Cloudy : rain a.m. and p.m. 26. Cloudy : thunder
p.m. 27. Fine: snow early a.m. : snow p.m. 28. Cloudy. 29. Fine: melted snow.

Sandwich Manse, Orkney. — Feb. 1. Bright: clear large halo. 2. Bright: clear:
fine. 3. Bright : cloudy. 4. Damp : showers. 5. Showers. 6. Snow-showers :
cloudy. 7. Rain : showers. 8. Snowing : aurora. 9, 10. Snow-showers.
11. Bright : cloudy. 19.. Bright : cloudy : thaw. 13. Cloudy. 14. Drizzle:
cloudy. 15,16. Showers: sleet. 17. Bright : clear aurora. 18. Cloudy: snowing.
19. Snow-drift. 20. Snow-showers. 21. Bright: snow-showers. 22. Snow-
showers : drift. 23. Bright : drift. 24, 25. Drift. 26. Bright : snow.showers.
27. Bright : haze. 28. Bright : clear. 29. Bright : large halo.

Applegarth Manse, Dumfries-shire.— --Feb. 1. Frost. 2. Frost and snow. 3.
Frost : clear. 4. More snow : frost. 5. Frost I clear. 6. Frost. 7. Snow.
8. Snow: frost. 9. Thaw. 10, II. Frost. 12. Snow: frost. 13. Thaw.
14. Thaw and fog. 15. Fine thaw and rain. 16. Slight showers. 17. Showers
p.m. 18. Very wet. 19. Rain : slight showers. 20. Frost again. 21. Frost :
a little snow. 22. Frost : snow-shower. 23. Heavy fall of snow : frost. 24—
27. More snow : frost. 28. Snow and thaw. 29. Rain p.m.

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THE
LONDON, EDINBURGH and DUBLIN

PHILOSOPHICAL MAGAZINE

AND

JOURNAL OF SCIENCE.

[THIRD SERIES.]

MAY 1844.

XLVIII. On the practice of the Calotype Process of Photo-
graphy. By Geo. S. Cundell, Esq.*
(1.) TN the year 1839 was published in France the inven-
tion of M. Daguerre, now so well known by the
justly celebrated name of its author. Shortly afterwards, that
of Mr. Fox Talbot, called " the Calotype," was published in
England ; kindred arts having for their object the production
of permanent pictures by means of the camera obscura. If
the comparative merits of the Daguerreotype and of the Calo-
type were to be judged of by the interest which each has ex-
cited, or by the progress which has been made in the practice
of either, the English invention would justly be classed in a
very subordinate rank ; for, while the Daguerreotype was at
once understood, and successfully practised, over the whole
civilized world, most of the few persons who have attempted
the sister art, after failing of success, have given it up in dis-
appointment.

2. But notwithstanding the little progress the calotype has
yet made, there is reason to believe that it only requires to be
better known to be appreciated as an art not less beautiful than
that of Daguerre, and that it is well deserving of a much
greater share than it has yet received of the public attention.
It requires but little apparatus; its materials are compara-
tively inexpensive; and it is possessed besides of the striking
advantage, of yielding a great number of perfect copies from
every original picture. ,

3. Had Mr. Talbot thought fit to publish directions for the
details and refinements of his process, as minute and explicit
as those given by M. Daguerre, his invention, it is probable,
would now have stood in a very different position ; there can
be little doubt that it also, would by this time have been greatly

* Communicated by the Author.
Phil. Mag. S. 3. Vol. 24. No. 160. May 1844. Y

322 Mr. Cundell on the practice of the Calotype Process.

improved upon ; and it is with the hope of promoting its im-
provement, by removing some of the difficulties left at the
threshold, and opening the way for the entrance of labourers
into the vineyard, that I have been tempted to offer this little
treatise to the public. They had been better pleased, no doubt,
to have received such an offering from the hands whence it
ought to have come; but with every respect for the distin-
guished author of the calotype, I hope I may without impro-
priety do that which he has omitted to do, by furnishing plain
directions, from my own experience, by which calotype pic-
tures may be produced, without much difficulty and with tole-
rable certainty and success.

4>. The Daguerreotype plate owes its sensibility to the
iodide of silver, obtained by exposing the metal to the vapour
of iodine. The same compound, iodide of silver, is the foun-
dation of the calotype also; but it is obtained by a "humid"
process, by the decomposition of nitrate of silver, upon the
surface of paper, by means of a solution of the iodide of po-
tassium. It has been found that paper so prepared, when
treated with gallic acid, becomes exceedingly sensitive; and
that upon the slightest exposure to daylight, under particular
treatment, it will become perfectly black and opaque. Hence
its fitness and adaptation to receive the delicate but feeble im-
pressions of the images formed in the camera obscura, which
imprint upon it what has been called a "negative" picture,
having the lights and shadows of nature reversed. This "ne-
gative," when fixed and rendered permanent, is used as a
matrix; and, by a simple and well-known process, a great num-
ber of impressions may be photographically printed from it,
representing objects not only in true light and shadow, but
true also in relation to right and left.

5. Before anything good can be produced in calotype, the
operator must be provided with a properly constructed camera
obscura. The cameras met with in the shops are generally
made after the French model, with nominally achromatic lenses,
of the plano-convex figure, and of a short focus. Without
presuming to disparage these, which no doubt will give a por-
tion of well-defined picture in the centre of the field, sufficient
for a single portrait, I would venture to recommend, on the
authority of Dr. Wollaston, a lens of the meniscus figure,
having the radii of its curves in the proportion of two to one.

6. He has shown, in an essay on the particular subject (in
the Philosophical Transactions for 1812), that the meniscus
figure, when properly "stopped"* is peculiarly adapted to the

* His improvement is a very striking one ; and it seems odd, that the
principal part of it, upon which the effect chiefly depends, his mode of stop-

Mr. Cundell on the practice of the Calotgpe Process. 323

camera obscura, from its property of producing a compara-
tively fiat and focal field throughout the picture, when the
picture is received upon a plane surface (§ 9). Without under-
valuing the advantage of corrected aberration, it may well be
doubted whether you do not lose more than you gain by the
plano-convex figure, even though achromatic, from the im-
possibility of bringing its picture, when of any extent, to a
tolerable focus. Achromacy is no doubt desirable; but in calo-
type, where the image is not to be magnified, it is by no means
indispensable, as any one may prove who fairly tries the ex-
periment; and the expense of a really achromatic lens of an
adequate aperture must put it in a great degree out of the
question. Perhaps the best substitute for it would be a lens
of blue glass, which would transmit nearly the whole of the
chemical rays to a common focus. But of whatever figure the
lens may be, and of whatever colour, it will not be unimportant
that the focus be considerably longer than that commonly used.

7. In order that a picture in perspective may be seen with
truth and satisfaction, it is necessary that it be seen from a
particular point of view, in which the eye has the same rela-
tion to the picture that it would have to the object represented.
The picture must subtend at the eye the same angle as the
object ; and unless it do, it will always look more or less dis-
torted and unnatural. The principle is well illustrated in
the diorama, the illusion and the charm of which depend in
no small degree upon the placing of the spectator at the proper
height and distance; but the principle applies to all pictures
in perspective, and to camera pictures in particular, which are
wonderfully improved when placed at the proper distance from
the eye. Calotype pictures are not intended to be looked at,
and are seldom viewed, at a shorter distance than twelve inches;
and in order that such a picture viewed at that distance may
be seen in true perspective, the lens of the camera must be of
twelve inches focus. In portraiture the effect may be less ob-
vious than in architecture, or in general subjects ; but there
can be no doubt that a portrait taken by a lens of six inches
focus, viewed at the distance of twelve inches, would lose a
great part of any truth or likeness it might really possess.

8. For these reasons the lens oughtnot perhaps to be less than
twelve inches focus; and, if mounted in the manner shown in the
subjoined drawing, it will be found to be generally convenient.

There is no novelty in this construction, unless perhaps in
the introduction of the diaphragms A B and C D, and in the
elongation of the mouthpiece; both of which are useful in pro-
ping out and admitting the light, is precisely the part which (so far as I am
aware) has been entirely overlooked in practice, and in every popular trea-
tise on the subject.

Y2

324 Mr. Cundell on the practice of the Calotype Process.

tecting the picture from all external light, except that which
emanates from the objects to be copied ; the rays from the

direction b being intercepted at B, and those from d at D.
The paper is placed between two plates of glass, introduced
at the open end G H, and these are pressed together and se-
cured in their place by means of a detached door having a re-
volving bar behind it, the extremities of which work in grooves
in the sides of the outer case *.

9. By reference to the diagram, it will be seen that by means
of the diaphragm or " stop " E F, the rays from the barb of
the arrow are excluded from the upper and received only upon
the lower half of the lens, upon which they fall at a compara-
tively high and equal angle of incidence. They are thus less re-
fracted than they would otherwise be, and their focus is not only
sharpened but elongated. By this means, the picture, instead
of being formed in the usual curve, is formed much nearer to
a straight line in the plane of the paper placed to receive it.

10. A lens of twelve inches focus ought to have an aperture
of 2'4 inches. The diaphragm at E F (in which the princi-
pal virtue of the instrument resides) ought to be placed 1 '5
inch in advance of the lens, and its opening ought not to ex-
ceed 1*2 inch. By using one of a smaller opening, a much
finer image will be obtained, but at the sacrifice of light : at

* The instrument, much improved, may be had of Mr. Dennis, 118 Bi-
shopsgate Street Within.

Mr. Cundell on the practice of the Calotype Process. 325

short distances, however, on account of the increasing diver-
gency of the rays, only a small opening, admitting the mere
centres of the pencils, can be used with advantage. The size of
the plate glasses may be eight inches by six.

11. It must be observed of this camera, and of all others
which are not achromatic, that there is a peculiar adjustment
required of the focus, the not attending to which has been the
cause of much failure and disappointment. The instrument
must be adjusted to what has been appropriately called the
chemical focus, which differs materially from the optical or
visible focus, as will be seen by the following Table, in which
the two are contrasted ; the former being about one thirty-
sixth part shorter than the latter for parallel rays, and for di-
verging rays in proportion.

Principal focus

= 12 inches *.

Distance of

Visible

Chemical

object.

focus.

focus.

feet.

inches.

inches.

inch.

5

1500

14-49

0-51

6

1440

13-93

0-47

7

14-00

13-55

0-45

8

13-71

13-28

0-43

9

13-50

13-09

0-41

10

13-33

12-93

0-40

12

1310

12-71

0-39

15

12-86

12-47

0-39

18

12-70

1232

0-38

24

12-52

12-16

0-36

50

12-24

11-90

0-34

100

12-12

11-78

034

12. It will be found convenient to insert one or more strips
of white wood in the sliding part of the camera, as shown in the
drawing, and to graduate these with the foci produced by the
different "stops" used at E F. This graduation is best done
by first accurately determining the visible foci (by daylight) of
two fiducial points near the extremities of the scale, by means
of a test object and a magnifier, and then setting off by mea-
sure the calculated differences ; thus, for a twelve-inch lens,

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* For lenses of a different focus, the graduation will be in proportion, at
proportionate distances; thus, for a lens of six inches, the spaces will be
one-half the above, at half the distances.

326 Mr. Cundell on the practice of the Calotype Process.

When the instrument is thus graduated, the focus may be set
in an instant (with an accuracy which is quite unattainable by
the unassisted eye), by merely measuring the distance of the
object if near, or by guessing at it if out of reach.

13. To produce a calotype picture there are five distinct
processes, all of which, except the third (§25), must be per-
formed by candle-light; they are all very simple, but at the
same time all of them require care and attention. The first,
and not the least important, is

14. The Iodizing of the Paper. — Much depends upon the
paper selected for the purpose; it must be of a compact and
uniform texture, smooth and transparent, and of not less than
medium thickness. The best I have met with is a fine satin
post paper, made by " R. Turner, Chaffbrd Mill." Having
selected a half sheet without flaw or water-mark, and free
from even the minutest black specks, the object is to spread
over its surface a perfectly uniform coating of the iodide of
silver, by the mutual decomposition of the two salts mentioned
in § 4. There is considerable latitude in the degree of dilu-
tion in which these salts may be used, and also in the manner
and order of their application ; but as the thickness and re-
gularity of the coating depend upon the strength of the so-
lution of nitrate of silver and upon the manner in which it is
applied, I think it ought by all means to be applied first,
before the surface of the paper is disturbed ; and I am in-
clined to believe, that if the solution be used of double the
strength suggested by Mr. Talbot, the coating will be found
more perfect and continuous, and will produce better pictures.
I use, accordingly, a solution of the strength of thirty grains
to the ounce of distilled water.

15. The paper may be pinned by its two upper corners to
a clean dry board a little larger than itself; and, holding this
nearly upright in the left hand, and commencing at the top,
apply a wash of the nitrate of silver thoroughly, evenly and
smoothly with a large soft brush, taking care that every part of
the surface be thoroughly wetted, and that nothing remain
unabsorbed in the nature of free or running solution. Let the
paper now hang loose from the board into the air to dry, and
by using several boards time will be saved.

16. The nitrate of silver spread upon the paper is now to
be saturated with iodine, by bringing it in contact with a so-
lution of the iodide of potassium ; the iodine goes to the silver
and the nitric acid to the potash.

17. Take a solution of the iodide of potassium of the strength
of 200 grains to a pint of water, to which it is an improvement,
analogous to that of M. Claudet in the Daguerreotype, to add

Mr. Cundell on the practice of the Calotype Process. 327

fifty grains of common salt. He found that the chlorinated
iodide of silver is infinitely more sensitive than the simple
iodide ; and by this addition of common salt, a similar, though
a less remarkable, modification is obtained of the sensitive
compound. Pour the solution into a shallow flat- bottomed
dish, sufficiently large to admit the paper, and let the bottom
of the vessel be covered to the depth of an eighth of an inch.
The prepared side of the paper having been previously marked,
is to be brought in contact with the surface of the solution,
and, as it is desirable to keep the other side clean and dry, it
will be found convenient, before putting it in the iodine, to
fold upwards a narrow margin along the two opposite edges.
Holding by the upturned margin, the paper is to be gently
drawn along the surface of the liquid until its lower face be
thoroughly wetted on every part ; it will become plastic, and in
that state may be suffered to repose for a few moments in con-
tact with the liquid ; it ought not however to be exposed in
the iodine dish for more than a minute altogether, as the
new compound, just formed upon the paper, upon further ex-
posure would gradually be redissolved. The paper is there-
fore to be removed, and, after dripping, it maybe placed upon
any clean surface with the wet side uppermost until about half
dry, by which time the iodine solution will have thoroughly pe-
netrated the paper and have found out and saturated every par-
ticle of the silver, which it is quite indispensable it should do,
as the smallest portion of undecomposed nitrate of silver would
become a black stain in a subsequent part of the process.

18. The paper is now covered with a coating of the iodide
of silver; but it is also covered, and indeed saturated, with salt-
petre and with the iodide of potassium, both of which it is in-
dispensable should be completely removed. To effect the
removal of these salts, it is by no means sufficient "to dip the
paper in water;" neither is it a good plan to wash the paper
with any considerable motion ; as the iodide of silver, having
but little adhesion to it, is apt to be washed off*. But the mar-
gin of the paper being still upturned, and the unprepared
side of it kept dry, it will be found that, by setting it afloat on
a dish of clean water, and allowing it to remain for five or ten
minutes, drawing it gently now and then along the surface to
assist in removing the soluble salts, these will separate by their
own gravity, and (the iodide of silver being insoluble in water)
nothing will remain upon the paper but a beautifully perfect
coating of the kind required.

19. The paper is now to be dried; but while wet, do not
on any account touch or disturb the prepared surface with
" blotting-paper," or with anything else. Let it merely be

328 Mr. Cundell on the practice of the Calotype Process.

suspended in the air, and, in the absence of a better expedient,
it may be pinned across a string by one of its corners. When
dry it may be smoothed by pressure. It is now " iodized "
and ready for use, and in this state it will keep for any length
of time if protected from the light. The second process is
that of exciting, or

20. Preparing the Paper for the Camera. — For this purpose
are required the two solutions described by Mr. Talbot, namely
a saturated solution of crystallized gallic acid in cold distilled
water, and a solution of the nitrate of silver of the strength of
fifty grains to the ounce of distilled water, to which is added
one-sixth part of its volume of glacial acetic acid. For many
purposes these solutions are unnecessarily strong, and unless
skilfully handled they are apt to stain or embrown the paper ;
where extreme sensitiveness therefore is not required, they
may with advantage be diluted to half the strength, in which
state they are more manageable and nearly as effective. The
gallic acid solution will not keep for more than a few days, and
only a small quantity therefore should be prepared at a time.
When these solutions are about to be applied to the iodized
paper, they are to be mixed together, in equal volumes, by
means of a graduated drachm tube. This mixture is called
" the gallo-nitrate of silver." As it speedily changes and will
not keep for more than a few minutes, it must be used without
delay, and it ought not to be prepared until the operator is
quite ready to apply it.

21. The application of this "gallo-nitrate" to the paper is
a matter of some nicety. I doubt if it be possible to apply it
successfully with brushes: and it appears to me, that one ap-
plication of the gallo-nitrate as completely unfits a brush for
a second, as the dipping of a sheet of paper in ink would unfit
it for writing upon. It will be found an improvement to apply
it in the following manner: — Pour out the solution upon a
clean slab of plate glass, diffusing it over the surface to a size
corresponding to that of the paper. Holding the paper by a
narrow upturned margin, the sensitive side is to be applied to
the liquid upon the slab, and brought in contact with it by
passing the fingers gently over the back of the paper, which
must not be touched with the solution.

22. It has been recommended at this stage, "to let the
paper rest for half a minute, and then to dip it into water and
dry it with blotting-paper," which I apprehend has been the
fruitful cause of much failure and disappointment, by the
staining and embrowning of the paper, and by the partial re-
moval of its sensitive surface.

23. As soon as the paper is 'wetted with the gallo-nitrate, it

Mr. Cundell on the practice of the Calotype Process. 329

ought instantly to be removed into a dish of water ; five or ten
seconds at the most is as long as it is safe at this stage to leave
the paper to be acted upon by the gallo-nitrate; in that space
of time it absorbs sufficient to render it exquisitely sensitive.
The excess of gallo-nitrate must immediately be washed off^
by drawing the paper gently several times under the surface
of water, which must be perfectly clean; and being thus washed,
it is finished by drawing it through fresh water, two or three
times, once more. It is now to be dried in the dark in the
manner described in § 19, and when surface-dry, it may either
be placed, while still damp, in the camera, or in a portfolio,
among blotting-paper, for use. If properly prepared, it will
keep perfectly well for four and twenty hours at least, pre-
serving all its whiteness and sensibility.

24-. The light of a single candle will not injure the paper at
a moderate distance ; but the less the paper, or the exciting so-
lution, is unnecessarily exposed, even to a feeble candle-light,
the better. Common river or spring water answers perfectly
to wash the paper, distilled water being required for the silver
solutions only. Stains of "gallo-nitrate," while recent, may
be removed from the fingers by a little strong ammonia, or by
the cyanide of potassium. The third process is that of

25. The Exposure in the Camera, — For which, as the ope-
rator must be guided by his own judgement, few directions
can be given, and few are required. He must choose or design
his own subject; he must determine upon the aperture to be
used, and judge of the time required, which will vary from a
few seconds to three or four minutes. The subject ought, if
possible, to have a strong and decided effect; but extreme
lights, or light-coloured bodies, in masses, are by all means to
be avoided. When the paper is taken from the camera, very
little, or more commonly no trace whatever, of a picture is vi-
sible until it has been subjected to the fourth process, which is

26. The bringing out of the Picture, — Which is effected by
again applying the "gallo-nitrate" in the manner directed in
§ 21. As soon as the paper is wetted all over, unless the pic-
ture appear immediately, it is to be exposed to the radiant heat
from an iron, or any similar body, held within an inch or two
by an assistant. It ought to be held vertically, as well as the
paper ; and the latter ought to be moved, so as to prevent any
one part of it becoming dry before the rest.

As soon as the picture is sufficiently brought out, wash it
immediately in clean water to remove the gallo-nitrate, as di-
rected in § 23 ; it may then be placed in a dish by itself, under
water, until you are ready to fix it. The most perfect pictures
are those which " come out " before any part of the paper be-

330 Mr. Cundell on the practice of the Calotype Process.

comes dry, which they will do if sufficiently impressed in the
camera. If the paper be allowed to dry before washing off
the gallo-nitrate, the lights sink and become opaque; and if
exposed in the dry state to heat, the paper will embrown; the
drying therefore ought to be retarded, by wetting the back of
the paper, or the picture may be brought out by the vapour
from hot water*. The fifth and last process is

27. The Fixing of the Picture, — Which is accomplished by
removing the sensitive matter from the paper. The picture,
or as many of them as there may be, is to be soaked in warm
water, but not warmer than may be borne by the finger; this
water is to be changed once or twice, and the pictures are then
to be well-drained) and either dried altogether or pressed in
clean and dry blotting-paper, to prepare them to imbibe a so-
lution of the hyposulphite of soda, which may be made by
dissolving an ounce of that salt in a quart (forty ounces) of
waterf. Having poured a little of the solution into a flat dish,
the pictures are to be introduced into it one by one; daylight
will not now injure them; let them soak for two or three
minutes, or even longer if strongly printed, turning and mo-
ving them occasionally. The remaining unreduced salts of
silver are thus thoroughly dissolved, and may now, with
the hyposulphite, be entirely removed, by soaking in water
and pressing in clean white blotting-paper, alternately; but
if time can be allowed, soaking in water alone will have the
effect in twelve or twenty-four hours, according to the thick-
ness of the paper. It is essential to the success of the fixing
process, that the paper be in the first place thoroughly pene-
trated by the hyposulphite, and the sensitive matter dissolved ;
and next, that the hyposulphite compounds be effectually re-
moved. Unless these salts are completely removed, they induce a
destructive change upon the picture, they become opaque in the
tissue of the paper, and entirely unfit it for the next, which is

28. The Printing Process, — The picture being thus fixed,
it has merely to be dried and smoothed, when it will undergo
no further change. It is however a negative picture (§ 4), and
if it have cost some trouble to produce it, that trouble ought
not to be grudged, considering that you are now possessed of
a matrix which is capable of yielding a vast number of beau-
tiful impressions. I have had as many as fifty printed from
one, and I have no doubt that as many more might be ob-
tained from it.

29. The manner of obtaining these impressions has been so

* I now find that a horizontal jet of steam answers better than anything
I have yet tried.

f Specific gravity 1014.

Mr. Cundell on the practice of the Calotype Process. 331

often described, and there are so many different modes of pro-
ceeding, that it may be sufficient to notice very briefly the best
process with which I am acquainted. Photography is in-
debted for it to Mr. Alfred Taylor, the eminent chemist, whose
pamphlet on the subject will supply every detail. His solution
is made by dissolving one part of nitrate of silver in twelve of di-
stilled water, and gradually adding strong liquid ammonia until
the precipitate at first produced is at length just re-dissolved.

30. .Some paper is to be met with, containing traces of
bleaching chlorides, which does not require any previous pre-
paration ; but in general, it will be found necessary to prepare
the paper, by slightly impregnating it with a minute quantity
of common salt. This may be done by dipping it in a solu-
tion in which the salt can barely be tasted, or of the strength
of from thirty to forty grains to a pint of water. The paper,
after being pressed in clean blotting-paper, has merely to be
dried and smoothed, when it will be fit for use.

31. The ammonio-nitrate of silver is applied to the paper
in the manner described in § 1 5 ; and when perfectly dry, the
negative picture to be copied is to be applied to it, with its
face in contact with the sensitive side. The back of the nega-
tive picture being uppermost, they are to be pressed into close
contact by means of a plate of glass; and, thus secured, they
are to be exposed to the light of the sun and sky. The ex-
posed parts of the sensitive paper will speedily change to lilac,
slate-blue, deepening towards black; and the light, gradually
penetrating through the semi-transparent negative picture, will
imprint upon the sensitive paper beneath a positive impression.
The negative picture, or matrix, being slightly tacked to the
sensitive paper by two mere particles of wafer, the progress of
the operation may from time to time be observed, and stop-
ped at the moment when the picture is finished.

32. It ought then, as soon as possible, to be soaked in warm
water, and fixed in the manner described in § 27.

33. In these pictures there is a curious and beautiful variety
in the tints of colour they will occasionally assume, varying
from a rich golden orange to purple and black. This effect
depends in a great degree upon the paper itself; but it is mo-
dified considerably by the strength of the hyposulphite, the
length of time exposed to it, by the capacity of the paper to
imbibe it, and partly, perhaps, by the nature of the light.
Warm sepia-coloured pictures may generally be obtained by
drying the paper, by pressure, and making it imbibe the hy-
posulphite supplied in liberal quantity.

The paper of " I. Whatman, Turkey Mill," seems to give
pictures of the finest colour, and, upon the whole, to answer

332 The Rev. D. Williams on the Killas Group of

best for the purpose; and the successors of that gentleman,
the Messrs. Hollingsworth, being so obliging as to prepare
some paper with a little salt added to the sizing material, it is
to be hoped, from its requiring no trouble or preparation in-
jurious to its surface, that the demand for it will be such as to
induce them in future to manufacture it as an article of com-
merce.

If the chemical agents employed be pure, the operator, who
keeps in view the intention of each separate process, and either
adopting the manipulation recommended, or improving upon
it from his own resources, may rely with confidence upon a
satisfactory result.

London, February 1, 1844.

XLIX. On the Killas Group of Cornwall and South Devon;

its relations to the subordinate formations in Central and

North Devon and West Somerset ; its natural subdivisions ;

and its true position in the scale of British strata. By the

Rev. David Williams, Corresponding Member of the Boy al

Geological Society of Cornwall*.
T NOW exhibit to the Society maps, coloured geologically,
from Bridgewater in Somersetshire to the Land's- end in
Cornwall, with a section, from the Foreland on the Bristol
channel to Lantioc bay, east of Fowey on the English chan-
nel, to show the superposition of the Cornish killas with re-
gard to all the subordinate formations with which it is inse-
parably associated, and the four natural subdivisions into
which it resolves itself by characteristic mineral and organic
types, which are persistent throughout their entire range.
This great and important classification has forced itself upon
me by the constant repetition of the same successions in every
traverse I have made of the killas country from sea to sea.

The innumerable minute details of strike and dip which 1
have registered from north to south and from east to west,
fully convince me that the Cornish killas in the ascending
order crowns a magnificent consecutive series such as I have
illustrated on the map and section, a series however (com-
plete and perfect as it is in all its particulars) which manifestly
constitutes only a part of some vast system as yet unfolded.

I formerly subdivided the entire group into ten component
members, the nethermost of which was the Cannington Park
limestone near Bridgewater ; but many circumstances have
since induced me to suspect that, though geographically it

* From the Annual Report of the Royal Geological Society of Cornwall,
1843. Communicated by the Author, and with corrections by him.

Cornwall and South Devon. 333

was associated with the Quantocks, it geologically appertained
to the Mendips, and troughed away towards them, as Mr.
Conybeare has long ago suggested*. In this view the Fore-
land or Dunkerry sandstones (No. 2.) will provisionally con-
stitute the mineralogical base of the entire system; these
are almost identical in mineral composition with the old red
sandstone of Monmouthshire and the Mendips, close by, and
are, I believe, a more southward prolongation of it. I deny
more confidently than ever, that there exists any axis or anti-
clinal line of fracture in the whole of Exmoor; every geolo-
gical fact, and all the associated physical evidences negative
such a supposition. The true mechanism of the structure of
Exmoor and the Quantocks is, as I announced at Liverpool
in 1837, that these red sandstones and shales (hitherto con-
taining only plants), with white quartz conglomerates, and
green compact calcareous grits, emerge from beneath the
Linton slates and the other overlying masses, and culminate
in three parallel mountain folds with their corresponding in-
verted flexures or valleys, but are finally lost on the north-
east of the Quantocks, where their exposed summits, barely
showing through the ridges of the new red sandstone in long
low undulations, indicate them to be rolling away towards the
Mendips, the mineral axis of which is old red sandstone, as
has been shown long since by Dr. Buckland and Mr. Cony-
beare f. This view of the true position of the Devonian sy-
stem, viz. that it occupies an enormous interval between the
old red sandstone and the mountain limestone, was first sug-
gested to me about two years ago, on observing in the neigh-
bourhood of Bristol a hard junction between those two for-
mations : subsequently I have been much gratified on finding
that Mr. Hopkins and Mr. Daniel Sharpe have, by indepen-
dent observations at different localities in the north of England,
remarked an unconformity also of strike and dip between
them. Mr. Hopkins observes, " After the elevation of the
older rocks, including the old red sandstone, the whole di-

* Geology of England and Wales, — Section from the Land's-end to the
German Ocean.

f It is proper to observe that a thick band of dark blue and oftentimes
coarse dull arenaceous limestone is included in these red sandstones in
Croyd hill near Minehead and along the east and north-east flank of the
Quantocks, very essentially differing from the cornstones or any calcareous
beds hitherto described as pertaining to the old red : it commonly contains
in its shales and planes of deposition carbonaceous matter oftentimes like
powdery coal smut, and as often in extremely thin films with a high metallic
lustre : it also contains corals in great abundance, which Mr. Lonsdale re-
cognised as the same species as some others he had described from the
lower Palaeozoic rocks of South Wales.

334< The Rev. D. Williams on the Killas Group of

strict must have been under the sea, and subjected to the
powerful action of denuding causes, by which the upturned
edges of the disturbed beds were worn to an even surface,
and the existing masses of old red conglomerate washed into
the hollows; the mountain limestone was deposited on the
worn and even surface of these older rocks*." Mr. Hopkins
states previously, " The mountain limestone reposes uncon-
formably on the older formations, which, within the limestone
band, occupy the surface f." At the close of a paper published
in the London and Edinburgh Philosophical Magazine for
July 1842, but dated May 17th, and communicated to the
editors before Mr. Hopkins's Memoir was read at the Geo-
logical Society, I indirectly adverted to the views I enter-
tained of the position of the Devon and Cornwall beds ; and
in an announcement of them at the meeting of the British
Association, held at Manchester in the same month, I was
constrained to invoke an elevation and submergence of the
old red sandstone prior to the deposition of the mountain
limestone, to as great and perhaps greater extent than was
contended for by Mr. Hopkins %. Mr. Sharpe has also ob-
served an unconformity of strike and dip between the old red
sandstone and mountain limestone above Kirkby Lonsdale,
the angle of dip varying five degrees, and the strike fifty :
" further westward," he observes, " the want of conformity
is still more manifest," the variation in strike amounting to
seventy degrees, and lower down the valley of the Lune
other instances still more remarkable are adverted to. Mr.
Sharpe concludes "there is abundant evidence of both the
old red sandstone and Ludlow rocks having been dislocated
before the accumulation of the mountain limestone, as the
limestone of Kendal Fell rests in a nearly horizontal posi-
tion upon the upraised edges of an anticlinal ridge of Lud-
low rock, from which a covering of old red sandstone has
been partially denudated §." Now, if a break or interruption
in the succession actually exists between them, as is indicated
by such hard junction in the west of England, and uncon-
formity in the north, the interval implied might of course be
sufficiently capacious for the reception of all the Devonian and
Cornish rocks, and others which may be elsewhere still above
them.

* Geological Proceedings, No. 90, p. 760 [or Phil. Mag. S. 3. vol. xxi.
p. 472].

f Ibid. p. 757 [or Phil. Mag. S. 3. vol. xxi. p. 469].

| Transactions of the Sections, p. 61.

§ Geological Proceedings, No. 85, pp. 605 and 607 [or Phil. Mag. S. 3
vol. xxi. p. 558, 559, 561].

Cornwall and South Devon. 335

These red sandstones (No. 2) are succeeded in an ascending
and critically consecutive order by eight other great series of
deposits, which severally vary in their mineral types and organic
contents, the last or uppermost of which is the Cornish killas.
That this great group overlies the floriferous or plant-bearing
series, as I have termed them, or the " carbonaceous rocks,"
as they have been designated by Sir H. De la Beche and
Professor Phillips, is as capable of demonstration as any geo-
logical fact of superposition on record. The diagrams which
I now exhibit 1 have carefully copied from natural sections
(almost as simple as those of tabular superposition), which
show the killas to rest, as if tranquilly piled, on the plant or
carbonaceous beds at Boscastle, Petherwin, Tavistock, &c.&c,
and these are confirmed by the same continuous carbonaceous
rocks in their most prominent and characteristic mineral and
organic types, closely investing nearly the whole of Dartmoor,
and underlying the entire killas country on the east, south,
and west of it.

These facts confirm more strongly, if possible, the opinion
I have long since expressed*, and I cannot but think they
should either be disproved, or their legitimate consequences
admitted.

The killas group naturally resolves itself into four subdivi-
sions, which are severally characterized by appropriate mineral
types and varying per-centages of organic genera and species :
these different members are inseparably linked together on
their confines, by a common alternation of beds, and by in-
sensible mineral gradations, and in the great natural scale are
arranged in the following descending order: —

No. 4. The Ichthyphorous, or Fish-bearing killas.

No. 3. The Metalliferous killas.

No. 2. The Padstow, or Tamar killas.

No. 1. The Tintagel, or Clymenien killas.

There is nothing arbitrary or inconstant in this fourfold
division of the killas group, though from the several granitic
interferences, and other derangements, they oftentimes de-
viate considerably in their strike, and present a greater or less
amount of surface according to the angle of inclination which
their beds exhibit, or according as they may be repeated or
not by flexures, and the varying bulk of matter which enters
into their composition at different localities : with these limi-
tations, and the circumstance that Nos. 1 and 4 are vast
sphenoid masses, the former thinning away to nothing up the

* See " Plausible reasons and positive proofs, showing that no portion
of the Devonian system can be of the age of the old red sandstone." By
the Author, London and Edin. Phil. Mag. Feb. 1842.

336 The Rev. D. Williams on the Killas Group of

Fowey estuary, near Lostwithiel, and the latter not being
continued to either the south or the east of Dartmoor, every
traverse made at right angles to the direction of their strike
or bearing gives the same succession of the same peculiar
mineral deposits, and the same sections throughout the entire
killas region, from Torbay on the east to the Bristol channel
on the west.

No. 4, though containing interpolations of red and gray grits
and impure calcareous beds, is usually abundantly variegated
as a whole, its strata being red, green, greenish gray, purple,
and mottled purple and green, commonly glossy and unc-
tuous, and of a more exquisitely delicate texture and fo-
liated structure than any I have ever met with. It is charac-
terized by the abundant remains of fish, which were first dis-
covered by the Messrs. Couch of Polperro, as has been fairly
admitted, and some of which have been exhibited to the So-
ciety by Mr. Peach. They preeminently characterize this
upper department of the killas, sometimes to such an amount
that I entertain no doubt that a fish-bone bed as replete with
their remains as that at Watchet and Aust cliff' in the
Lias of the Severn, will hereafter be discovered : I have my-
self in fact found a fragment of such Ichthyolite bed in a por-
tion of cliff which had fallen down on the shore, but have
not yet detected it in situ, — it is a consolidated congeries of
fish remains. Of the great number of specimens I have col-
lected, or which have been kindly shown me by Mr. Peach and
Mr. Couch, with the exception of some defensive fins and fin
rays which might or might not be " Onchus," they all appear
to me to differ even in genera from any which have hitherto
been figured from the Ludlow rocks or the old red sandstone.

This member of the killas series is of considerable thick-
ness to the eastward, but gradually decreases in dimensions
as it advances to the westward : on the eastern coast it extends
from Man sands near Brixham, by Moss point on the Dart,
and East Allington and Aveton Giffbrd, to the Start and
Prawle points, and the Belt Head and Tail ; where, though
oftentimes in such conditions as refer to partial reduction by
active heat, and even to semifusion, it may be followed and
identified. Along its northern line from Man sands to near
the mouths of the Erme and Yealm rivers, in Bigbury bay,
it contains repeated interpolations of the red and gray grits
and red slates of the next subordinate killas series, No. 3, and
everywhere rests conformably upon it, with an almost perma-
nent southern dip as far as the parallel of Stokenham and
Kingsbridge, along which its beds are thrown back into a
fan-shaped arrangement and a high northern dip : from Slap-

Cornwall and South Devon. 337

ton sands therefore on the east, to Thurlestone in Bigbury
bay on the west, they present a synclinal axis : from thence
round Bigbury bay to Yealm mouth, and thence in a line
drawn to Cawsand on the west of Plymouth sound, it overlies
No. 3 killas with a high southern dip : round Whitsand bay
it constitutes the far greater portion of the cliffs, in a narrow
belt, sometimes thinning out in its deeper recesses, and un-
masking the metalliferous killas, which is seen incontrovertibly
to pass into and underlie it: this is notably the case in the
deeper inlet of Looe bay, where, from Millendreth to near
Hannafore point, there is not a vestige of it; Looe island
however consists entirely of it, where its beds on the north
side dip S. 40°, and thence increase their inclination to verti-
cal, and apparently 80° to 85° N. on the south end, in a fine
fan-shaped form.

The eastern cliffs, from West Looe to Hannafore point,
where the fish-bearing killas again sets on, afford fine un-
broken sections north and south, showing the gradual trans-
ition of No. 3 into No. 4, and the indisputable underlie of the
former. From Hannafore point to near Hendrasick, No. 4 dips
steadily and uniformly to the south and south-south-east at
high but varying angles: at Hendrasick cove, a great up-cast
fault has brought No. 3 killas into hard collision with the middle
beds of No. 4, which, after a variety of strange contortions
plunge headlongdownwards after the junction line; but south-
ward of this, on to Oarstone, and westward, to Talland, Pol-
perro, Lantioc bay, and the Fowey ferry at Bodinick, they
settle down to a high north and north-eastern dip. From Lan-
tioc bay their southern line or terms, quitting the coast, strike
off by Lanteglos and the Fowey ferry to " ancient inscribed
stone " on the Ordnance map, on the north-west of Fowey,
where they curve round and follow nearly the north and south
line of road to Lostwithiel for two miles and a half, from
whence they tread off obliquely to the north-east to Lantine,
on the west bank of the river, opposite St. Winnow, where,
meeting with their northern line, they taper out to nothing :
from Lantioc bay, after their south, and round their west
line just described, they are manifestly included in a trough
of the subordinate fossiliferous killas No. 3, which supports
them everywhere along its northern and north-eastern confines,
and is distinctly seen to emerge from below them at Lantioc
bay ; at a little south of Bodinick, and north of Fowey, and
all round their curved line up to Lantine. From Pencarrow
point and the Greber head round by Par sands and St.
Blazey, to the granite at Lanlivery, a powerful abnormal force
has wrenched the beds out of their mean direction into a huge

Phil. Mag. S. 3. Vol. 24. No. 160. May 1844. Z

338 The Rev. D. Williams on the Killas Group of

elbow with a flexured outline, from the inner angle of which
No. 4 killas is deflected with them into a nearly north and
south strike after the Fowey river and its eastward and west-
ward banks.

With the exception of fish, other organic remains appear
to be very rare; Mr. Couch, jun., however, has discovered
several specimens of a small or young Bellerophon at Polperro,
and I have collected Spirifers, &c. up the Dart, and Corals and
Crinoidea in it at Whitsand bay, and Beeson and Hall sands
near the Start.

An abandoned mine near Lansallos, apparently one of the
many monuments in Cornwall of the speculative epidemic of
1835, is the only instance I remember of any workings for
metals, either ancient or modern, throughout its entire range.
It affords good blueish-gray roofing-slates near Dartmouth,
and would yield them also at other localities, probably, if
sought for, but I know of no other quarries.

I have gone into details in regard to this series more pre-
cisely and particularly than I propose to give of the others,
because its true position, and its relations to them, have hitherto
been altogether mistaken : that it does not underlie the great
killas mass, or in any way constitute " a south Devon axis,"
nor in any sense correspond with either of the Exmoor series,
must be obvious from these structural details, and the fact
that it is of posterior formation to the floriferous and carbona-
ceous rocks. The distance in miles, in fact, along which it
gives steady southward dips compared to that at which its
beds are reversed and present northern dips (to say nothing
of the permanent underlie of the abundantly fossiliferous and
metalliferous killas No. 3, the next in descending order), is
thirty-four of the former and eighteen of the latter.

No. 3, or the metalliferous killas, is in almost diametrical
mineral and organic contrast to the former series, so much so
that anything like glossy, delicate and crystalline slate, and
fish remains, are as rare exceptions in it as metalliferous lodes
and red and gray sandstones, and coarse arenaceous schists,
with innumerable organic remains of many genera and spe-
cies, are in the other. The abundant evidences of its under-
lying the fish-bearing killas No. 4, have been referred to in
the description of that series.

No. 3 may be described as a vast detrital deposit of red
and gray grits, containing throughout greater or less admix,
tures of volcanic ash or mud, in the form of blue or gray
schists, red slates, &c. From this circumstance, and the
enormity of its mass, it constitutes a broad and well-defined
line of demarcation, and an invaluable middle term in a classi-

Cornwall and South Devon. 339

fication or analysis of the Cornish killas: at present I can
only express myself generally, by observing that whether
coarse arenaceous schist obtains in some localities, or red and
gray grits, either passing into quartz rocks, or thickly inter-
sected by quartz veins, predominate in others, a sufficient
proportion of the lesser ingredients is uniformly present or
close at hand to determine their inseparable relations.

It contains nearly all the lodes of tin and copper (including
those of the granites which have been generated by its re-
duction in the volcanic furnaces) of any value in the killas
group, except the inferior mines about Tavistock*, and on
either side of Hingston down, between Tavistock and Cal-
lington. One of its lodes at Carn-brea, has probably yielded
as much ore as all those Tavistock and Callington mines
together.

All the coral limestones of Torbay, from Babbacombe to
Berry head, are included in its upper terms there, which is
sufficiently shown by its lower arenaceous schists and grits,
such as overlie the Plymouth limestones of Mount Batten and
Plymstock, being protruded through the Torquay f and Brix-
ham limestones, viz. at Meadfoot sands in the former case,
and Mudstone sands in the latter ; and by those limestones
containing thick interpolations of the same red slates (e. g.
Daddy-hole cove near Torquay, &c. &c.) which pass from
No. 3 killas into No. 4 above, and by the limestones at Shark-
ham point, south of Brixham, with their upper red grits and
schists being closely associated with, and immediately under-
lying, the delicate upper killas No. 4 at Man sands.

The Dart sections describe precisely the same history of
events, but in simpler and more explicit terms. From near
Totness to Sandridge point, a nearly four-mile succession of
red and gray sandstones, red slates, and calcareo- arenaceous
gray schists (the whole at intervals showing efforts of the tiny
coral creatures to establish their settlements), clearly underlie
the limestones of Watton and Galmpton; and these in their
turn, along the south shore of the Galmpton creek to Green-
away-house and Quay ferry, as clearly underlie the upper red
and gray grits and coarse schists, which continue for almost
a mile to near Noss point, and there support the upper killas
No. 4, which from thence to the mouth of the Dart, and the
little bay west of it on the south of Stoke Fleming, overlie
them with a permanent high southern dip.

* The rich and admirably-conducted mine Wheal Friendship is in the
floriferous or carbonaceous series below the killas.

t This remarkable fracture was first noticed, many years since, by Sir
Henry De la Beche. See Geological Transactions.

Z2

340 The Rev. D. Williams on the Killas Group of

The sections afforded by the Torbay coast on one side,and
by the Dart and intermediate country on the other, also clearly
show that the Torquay and Yalberton limestone (part of the
outer zone of a great curve) are conveyed to Churston Fer-
rers and Brixham by flexure and undulation: these limestones
become of very attenuated dimensions at Ditsham, Corn-
worthy, and Harberton ford west of the Dart, and are re-
presented further westward by a broad, calcareous, and often
abundantly fossiliferous band of grits and arenaceous schist,
apparent at Staddon point, and north of it in Plymouth sound,
at Hessenford, at East and West Looe, Fowey, Gorran, Car-
hayes, Veryan, and Gerrans bay, and probably at Watergate
bay on the north coast.

This member of the killas group, considerable as it is there,
is of insignificant dimensions on the east, compared to its vast
development on the west, where it is evidently augmented
by the introduction of new terms derived apparently from
local volcanic vomitories, the mud, ash, and elvan dykes,
whose contents even now, in numerous instances, show striking
affinities with the adjacent schists; the relative scarcity of
ash, mud, and porphyry dykes on the east, is attended by a
corresponding absence of much of the great schistose masses
on the west, and by a greater preponderance of red and gray
grits; whereas the gradually-increasing frequency westward
of the ash, schist and porphyry dykes, such as are seen from
Redding point (west of Plymouth sound) to Cawsand, and
abundantly elsewhere, is accompanied by augmenting inter-
polations of schistose matter (commonly however of an arena-
ceous character), and by less frequent beds of sandstone, al-
though the red and gray grits of St. Agnes beacon, or the
eastward clifi's of the Helford creek under Mawnan, would
suffer little in comparison with their cognate and congenerous
deposits at Cockington and Windmill hill near Torquay.
Nos. 3 and 4 killas, in fact, at either extremity, may be said to
be adjusted together like a solid parallelogram cut into two
wedges, the thin edge of the one being fitted against the broad
head of the other.

This series to the eastward forms a portion of the outer zone
of a great triple series of parallel concentric curves, the inner
one of which, composed entirely of the floral or carbonaceous
rocks, conforms perfectly to the south-east outline of the
granite of Dartmoor, and in consequence (taking about its
middle terms) it ranges from Cockington near Torquay, by
Cornworthy on the Dart, to Morleigh, Black-Down, the
south of Modbury, Holbeton, and Staddon and Redding
points on either side of Plymouth sound : west of the latter

Cornwall and South Devon. 341

and near the huge dyke of porphyry at Cawsand, a succes-
sion of dips from south to south-south-west, south-west, and
finally west, mark the angle from which its strike deviates to
St. Anthony, Sheviock, Hessenford, Bin-Down, St. Keyne,
and from thence follow the lofty ridges of heather-brown hills
by Pinnock common, Five-Barrow hill, Bodmin downs, St.
Breocks and Denzel downs to Watergate bay : from this nearly
central line, its beds on the west roll out to the southward in
endless repetitions, by long undulations or rapid flexures as
far as the granite of St. Ives on the north channel, and over
the whole Peninsula to the sea on the south, from Pencarrow
point east of Fowey, to Falmouth, the Lizard serpentine and
hornblende rocks, and the granite of Penzance.

Mr. Peach informs me that with the liberal loan of books
by the President, Sir Charles Lemon, he has been able to
identify the following Orthides which he has discovered in the
vicinity of Gorran, viz. Orthis lata, orbicularis, alternata,
canalis, Jlabellulum, testudinaria, interlineata, sordida, pli-
cata. Five of the above species have also been found in the
lower beds of the Palaeozoic rocks of Wales, one from the
higher beds, and the remaining three, according to the lists
of Professor Phillips and Mr. Sowerby, appear as yet to be
peculiar to Devon and Cornwall: I feel assured that my col-
lection will add some new and remarkable species to the above
when described (as I hope they shortly will be) by that ex-
cellent naturalist Mr. James Sowerby.

The remains of fish which occur so plentifully in the upper
series, are apparently as rare in this, as fossil mollusks, &c.
are in the other. Sir H. De la Beche has however found a
specimen at St. Columb Porth, and Mr. Phillips another at
Meadfoot sands near Torquay, — both in this formation*.

No. 2 killas is distinguished from the former by being an
entirely independent series throughout, except on its upper
and lower confines, along which it passes by alternation and
mineral gradation into Nos. 3 and 1 : its mean bounding line
from No. 3 is just above the range of the Plymouth limestones,
or their equivalent gray calcareous andfossiliferous slateswhich
supply their intervals of continuity : these are immediately
succeeded below by an enormously-thick suite of slates,

* See Phillips's Palaeozoic Fossils of Cornwall, Devon, &c. I have found
portions of fish-bones as low down as the Linton slates, and eoprolitic
looking bodies in the Trilobite slates near Barnstaple, and Mr. Parker, jun.,
late of Exeter, found a beautiful tooth in the Posidonia limestones of the
Coddon hill grit series at Doddiscomb Leigh, north of Chudleigh, which
Prof. Owen pronounced to belong to the Rhopalodon, a genus of fishes
hitherto found only in the Urals.

342 The Rev. D. Williams on the Killas Group of

strongly characterized as green, blue, purple and gray (the
purple chiefly prevailing), in almost endless alternation, down
to the upper beds of No. 1: abundant facilities of identifying
and observing their striking peculiarities as contrasted with
all or either of the others, are afforded more especially by
the cliffs on either side the Tamar, from Plymouth up to
near Pentilly castle on the eastward region, and the shores
of the Padstow estuary on the west, from Wadebridge to
Stepper and Pentire points at its mouth. The sections and
succession of the same mineral beds, with the same fossils in
the upper ones, and the same apparent absence of them in the
lower, are so complete along the Padstow shores, that, re-
garding the same variegated beds underlying the same gray
calcareous slates, and these in their turn in like manner un-
derlying the arenaceous and coarse schistose deposits of No. 3
on the south, — all the facts and circumstances were too stri-
kingly associated in the same order to permit me to entertain
much doubt of their identity even at an early period of my
survey, before I had proved their continuity throughout the
intermediate region, and collected along the north shore of
the Padstow river a greater abundance of the same Trilobites,
Mollusks, Corals and Crinoidea, than I had gathered among
the same gray calcareous slates in the same relative position
near Plymouth.

Another marked and peculiar feature of this series, com-
pared to Nos. 3 and 4, is the total absence of the red and gray
detrital aggregates, or their coarse arenaceous admixture, such
as obtained throughout No. 3; while among all its vast terms
below the level of the Plymouth limestones and their repre-
sentative gray calcareous slates, east and west, I have hitherto
been as unsuccessful as Professor Phillips and Mr. William
Sanders in discovering any organic remains.

The limestones of Rock ferry opposite Padstow, — of But-
terville and Millaton near St. Germans, — of Plymouth, Yealm-
ton, Ugborough, Dartington, Berry- Pomeroy, Marldon,
Broadhempston, Ipplepen, Denbury, Abbot's and King's
Kerswell, Newton Bushel, and the east and west Ogwells,
belong to the upper terms of this series : judging from their
position and apparent underlie, and the intimate association
and intermixture of the purple and variegated slates, the Ip-
plepen, Denbury, Ogwells, and Newton Bushel limestones oc-
cupy a somewhat lower level than those of Little Hempston,
Bunkers hill (near Totness), Berry- Pomeroy, and Abbot's
and King's Kerswell, the latter being parted by, and associated
with, the upper gray calcareous and fossiliferous slates which
so commonly constitute the true equivalents of the Plymouth

Cornwall and South Devon. 343

limestones in their absence. My arrangement, in fact, of the
South Devon limestones has been governed entirely by the
order and succession of the killas and carbonaceous series
which there severally envelope them, and there is no other
rule, with security from error, which can be relied upon : the
slates and grits are constants, — the limestones accidents: in
this view the lime-rocks of Buckfastleigh, Ashburton, Bicking-
ton, Chudleigh, Ideford and Lyndridge, belong to the flori-
ferous or carbonaceous series, at about the same level as the
Bampton, Holcomb-Rogus, and Westleigh limestones on the
north, — all of them perhaps not much below the horizontal
parallel of the Petherwin. Some of the Chudleigh fossils, so
far as their evidence is of any value, are apparently identical
with some of the Petherwin.

It appears throughout to be as poor in metals as No. 4, as
I do not remember any lode of any promise or importance
being worked in it : it however affords roofing-slates which I
believe would equal in quality any in England, if quarried to
a sufficient depth, and with the requisite skill and capital.

Its northern line or boundary ranges from Staple hill on
the south-west of Bovey heath near Chudleigh, by the north
of Ingsdon, to a little south of Bickington and Ashburton ; a
little east of Buckfastleigh ; the south of Dean church ; South
Brent, and Ivybridge, to Beechwood and Sbaughwood, up to
which point it is in hard junction with the carbonaceous rocks :
from thence it takes a westward strike (accompanied by the
Tintagel killas No. 1, which there first sets on) to Tamerton
Foliot ; the north of Landulph ; Pillaton, and the north of
Quethiock, to the south foot of Caradon down : from hence
the entire series is represented chiefly by a narrow band of
the upper beds which flank the granite, by St. Neots to Car-
dinham, on the west of which it again expands, and ranges
after the west escarpment of the granite to Blisland and the
west of St. Breward, where meeting again with the lower
killas series No. 1 (which had described a great semicircle
from St. Ives round the same Bodmin Moor granite by its
eastern, northern, and north-western frontiers), they range
together in a nearly east and west direction by a little north
of Endellion, to the sea, between Portquin and Porteath :
strange as these remarkable lines may appear to some, I am
convinced they will be obvious to any one who will follow
them out as I have done.

Its southern terms are clearly deflected to the north-west,
on the west side of the Tamar, conformably to the deviation
in strike of No. 3 at Cawsand, as before adverted to : ad-
vancing in this direction towards Menheniot and Quethiock,

344 The Rev. D. Williams on the Killas Group of

the beds are seen to be no longer affected by the high angle
of dip which had displayed the entire series in such minute
detail and fine succession on the Tamar (as it also does from
Endellion to Constantine bay on the west of Padstow), but
they have settled down to so low an inclination as has per-
mitted the metalliferous series No. 3 to be expanded over
a great portion of the intermediate area, from a mile or two
north-west of St. Germans to nearly three miles north of
Liskeard.

A similar phasnomenon may be observed on the north-west
of Bodmin, over a considerable area where the upper gray
calcareous beds of No. 2, being sometimes apparently flat, or
at others inclining at a very low dip, conceal all the subor-
dinate variegated beds, until between St. Mabyn and St. Tudy
a higher angle brings up the blue, purple, green and gray
slates, which range continuously from thence by Endellion,
St. Minver, and St. Enodock, in a thick zone, to the north
and west of Padstow.

No. 1, the Tintagel or Clymenien killas, is of perfectly
unique mineral type, and a certain proportion of its fossils are
as yet equally appropriate and characteristic : it is almost uni-
formly a delicate pale green or greenish-gray slate, rarely a
blueish-gray, with quartz veins, commonly crystalline, — some-
times highly so: it is more or less calcareous throughout, but
its nether division from Tavistock on the east to Trevalga and
Tintagel on the west, contains masses of varying dimensions,
— oftentimes continuous for many miles together — of a highly
calcareous hornblendic and chloritic volcanic ash, which, on
decomposing, always constitutes a fertile soil; and at Brad-
stone, Kelly, Milton Abbot, Lamerton, and on the north of
Tavistock, affords some of the richest land in England.

That it forms the basis and supports the great killas super-
structure, is abundantly shown by explicit sections on either
side the Tamar, at inland quarries and cuttings, and on the
westward coast on the south of Port Isaac, where it passes in-
sensibly into No. 2 by neutral and alternating beds, and in-
disputably underlies it.

It yields tin and copper near Tavistock and Callington,
and lead and silver are worked in it to a greater extent than in
either of the killas series above it : excellent roofing-slates
are also quarried in it at Tintagel and Delabole on the west,
and at Mill-Hill near Tavistock on the east, and they have
also been proved at several intermediate points.

It passes into great lentiform bunches of lime-rock at Tre-
nalt and Petherwin near Launceston, which rest on, and are
parted by, black anthracitic slates, with thin layers of culm,

Cornwall and South Devon. 345

identical with such as are seen in the subjacent carbonaceous
rocks: these limestones to the eastward gradually thin out to
nothing, by irregular seams and fiat insulated cakes, among
true killas slates, but their earliest introduction is manifestly
by thin calcareous courses containing the characteristic Pether-
win fossils, among the underlying carbonaceous rocks, as may
be seen south of Landue mill near Launceston : these lime-
stones and associated slates are at times as abundantly loaded
with the remains of ancient life as any of the secondary rocks.
I have seen, in short, masses of lime-rockwhich decomposition
showed to be concretionary aggregates of organic structure :
of these I have been fortunate enough to obtain a very large
and varied assortment, many of them as yet undescribed:
among other large specimens of the beautiful Clymenia, I have
one which is nine inches in diameter.

This lowest member of the killas group does not appear at
all on either the east or the south of Dartmoor, and is first
met with on the south-west of it, a little north of Borringdon
wood, from which its southern line is of course the north one
of No. 2, already described, as far as a little south of St. Ives,
from whence it mantles round the inner zone of carbonaceous
rocks (which closely invest the Bodmin Moor granite on the
north and north-west as far as near Michaelstow, on the south-
south-west of Camelford), beyond which, falling in again with
No. 2, it accompanies it to the sea on the south of Port Isaac,
as before adverted tos, and does not appear afterwards in any
of the southern sections, a circumstance which, coupled with
the interposition of No. 2 along the Padstow estuary and to
the eastward of it, proves that the fossiliferous beds of Pether-
win are not conveyed to St. Columb-Porth, Newquay, &c,
as has commonly been supposed.

The accumulated evidences of its superposition, with regard
to the plant or carbonaceous rocks, are so strong, that any
attentive observer must admit that this series overlies and
passes downwards into them, by far more abundant and con-
clusive instances of simple section, gradation and alternation,
than even those carbonaceous rocks present on the north of
Devon, where they are now admitted on all hands to pass
by insensible transition into the older group of Exmoor :
the evidences of the former are certainly far more abun-
dant and demonstrable than anything of the kind I have ever
met with elsewhere, but exhibited at times on so vast a scale,
that the fidelity of their details is apt to be overlooked in the
magnitude of their proportions : in one instance, for example,
on the west bank of the Tamar, a traverse of six miles of
country, viz. from about two miles east of Petherwin to South

346 Mr. Grove on the Gas Voltaic Battery.

Hill near Callington, displays nothing but neutral beds, or
interchanges, or interlockings, of killas and carbonaceous
rocks, or of carbonaceous rocks fracturing and piercing through
the killas prior to the latter overwhelming them by its enor-
mous accumulations.

The Boscastle sections however, on the other hand, are
so readily comprehensible and simple as scarcely to admit a
doubt of it, corroborated as they are by the coast cliffs to
Tintagel, where the anthracitic schists, which are seen in mass
at Boscastle supporting the killas in almost a tabular form,
are observed to be continued upwards among the pale green
roofing-slates by repeated interpolations, of which ready ex-
amples may be seen close by the church at Trevalga, and a
little further south at Treworthat.

Such are the natural subdivisions of the great killas group,
founded on peculiarly appropriate types and continuity of
series, guided by which I trust I have sufficiently shown that
I have relied on, or been misled by, nothing which was arbi-
trary or inconstant.

Its position as the crowning extremity of a magnificent,
consecutive, and abundantly-varied series (as yet unrivalled
by any hitherto developed by rigid and direct analysis), 1
have endeavoured to show as clearly and in as much detail as
the nature of the communication admits, and so far its place
in the European system may be determined and mapped down
with certainty, if it shall eventually be shown, as I confidently
anticipate it will be, that I have been correct in my views,
that the entire Devonian and Cornish group is based on (pro-
bably the upper beds of) the old red sandstone.

L. On the Gas Voltaic Battery. — Experiments made with a
view of ascertaining the rationale of its action and its ap-
plication to Eudiometry. By W. R. Grove, Esq., M.A.,
E.R.S., Professor of Experimental Philosophy in the London
Institution.

(Continued from p. 278.)

TpXPERIMENT 7,-1 charged two batteries of two cells
-^ each, with hydrogen and dilute sulphuric acid in the
alternate cells. When tested by iodide of potassium, each
battery gave notable effects. One of these batteries was then
placed, together with a cup containing phosphorus, in a
shallow vessel of water; the phosphorus was ignited and a
large glass vessel inverted over the whole; the terminal wires
of the battery, carefully protected by thick coatings of cement,
passed under the edge of this vessel through the water, the

Mr. Grove on the Gas Voltaic Battery. 34-7

exterior surface of which was covered with oil, more effectu-
ally to prevent the absorption of air. The terminal wires
were then united and left so. After two hours, when the
oxygen of the surrounding atmosphere had been exhausted by
the phosphorus, the effect became more feeble, but continued
throughout the evening. The next morning, however, the
inclosed battery produced not the slightest effect upon the
iodide, the liquid had risen in the hydrogen tubes about 0*2
cubic inch, but no other effect was perceptible. On the other
hand, in the battery which had been placed by its side, charged
in the same way, and similar in every respect but in the fact
of being exposed to the atmospheric air, a very decided effect
was produced ; hydrogen had been evolved from one of the
platinums to the extent of 0*3 cubic inch in the cell contain-
ing liquid, and a decided effect was produced on the iodide.
The two batteries were left in this state for three more days ;
the decomposition and the evolution of hydrogen continued in
the exposed battery, but none was perceptible in the inclosed
one, although the liquid had risen a little more, viz. 0*1 cubic
inch in the hydrogen tubes of the latter. After the four days
above mentioned, the jar of nitrogen which covered the bat-
tery was taken away, and the action of the battery was tested
by iodide of potassium. At first there was no action, but after
about fifteen minutes, a slight action was perceptible; this
gradually increased, and in two hours the action was equal to
that of the battery which had been from the first exposed to
the atmosphere. I cannot but regard this experiment as a
conclusive negation of that view which regards hydrogen and
water as the efficient agents in the gas battery. The opinion
appears to me to have arisen from the circumstance of our
working always in an atmosphere containing oxygen, and also
from the fact of this latter gas being more soluble than hy-
drogen*. If we lived in an atmosphere of hydrogen, and if
this gas were equally or more soluble than oxygen, I have little
doubt that the converse effects would be observed. A battery
charged with hydrogen in one set of tubes and acidulated
water in the alternate ones, at first gives an effect nearly equal
to an oxyhydrogen gas battery, but the action rapidly declines
in the former, while it is constant in the latter. Even the or-
dinary action of the gas battery when charged with oxygen
and hydrogen appears to me unanswerable as to the point I
am now discussing. When we see a battery of a number of
cells at work, and the liquid gradually rising in the oxygen

* The tendency of oxygen to combine with platinum may also have its
influence. See M. De La Rive's various experiments on this subject, Bibl.
Univ. passim.

348 Mr. Grove on the Gas Voltaic Battery.

tubes, just in the proportion in which oxygen gas is eliminated
in the voltameter, and when in a similar battery placed by its
side, similarly charged, but not connected in closed circuit,
not the slightest rise takes place in any tube, it seems impos-
sible to adopt the conclusion that the oxygen has nothing to
do with the current. Here we have no slight galvanoscopic
effects, but chemical effects capable of quantitative admeasure-
ment, capable of being continued to an extent only limited by
the size of the apparatus, and equivalent to the chemical effects
observable at the voltameter. If, on the other hand, hydrogen
and water be the only active elements, what becomes of the
hydrogen ? If it combine with the water, we undoubtedly
should by this means be able to obtain a suboxide of hydro-
gen*, a result of which I have not seen the slightest symptom
in a long course of experiments on this subject. Even if we
assume the action of the oxygen to be a depolarizing one, as
suggested by Dr. Schcenbein, this comes to the same thing, as
this depolarization can only be accounted for as being effected
by the combination of the oxygen with hydrogen ; and we
might conversely assume this combination to be the efficient
cause of the current, and the depolarization to take place in
the hydrogen tubes. It seems to me that the effects at both
anode and cathode are reciprocally dependent. The matter
appears to me so clear that I should not have entered into de-
tail upon it, were it not for the published letter of Dr. Schcen-
bein above mentioned, and that the superiority of the hydro-
gen is prima facie very striking; knowing also the fondness
with which we all adhere to preconceived opinions, as the
consideration of the action of spongy or clean platinum on
mixed gases led me to the discovery of the gas battery, I felt
that I might be too apt to measure the correctness of my opi-
nions by the success of the experiments to which they led, and
therefore hesitated too confidently to rest upon what appeared
to my mind positive demonstration.

Having verified the rationale of the action of the gas bat-
tery, I now sought to extend it to other gases, and caused ar-
rangements of ten cells to be charged with such gases as were
sufficiently insoluble to remain in the tubes time enough for
experimental investigation. In all the following experiments,
besides the ten cells charged in series, a single cell charged
with similar gases and electrolyte was placed by the side, but
with the terminals unconnected : thus, when the battery cir-
cuit had been closed for some time, by comparing the changes
which had taken place in the battery tubes with those in the

* I see by a recent paper of Dr. Schcenbein that he believes this to be
the case, Archives de V ' Electricite, No. 7, p. 73.

Mr. Grove on the Gas Voltaic Battery. 349

detached and unconnected pair, the effects due to solution,
local currents, or other causes could be abstracted from those
due to circulating voltaic action.

I shall arrange the following experiments in the order in
which I instituted them, making such comments as may be
necessary to explain my own deductions from the resulting
phaenomena. When not otherwise mentioned, the electrolyte
will be considered as dilute sulphuric acid, sp. gr. 1*2.

Experiment 8. — A battery charged with oxygen and prot-
oxide of nitrogen produced no effect upon iodide of potassium.
Examined next day the liquid had not risen in the oxygen
tubes ; in the protoxide tubes it had risen to an average of 0*3
cubic inch, both in the battery and detached pair.

Experiment 9. — Oxygen and deutoxide of nitrogen pro-
duced a slight effect upon the iodide; the effect subsided after
the circuit had been complete for a few minutes. On exami-
ning the battery after the circuit had been closed for twenty-
four hours, the liquid in the oxygen tubes had not risen ; in
the tubes containing deutoxide of nitrogen, the liquid had
risen somewhat unequally in the different tubes to an amount
averaging 0*2 cubic inch; in the detached pair it had risen to
the same amount ; not the slightest voltaic effect was now pro-
duced by the terminal wires.

Experiment 10. — Oxygen and olefiant gas decomposed the
iodide, but rather feebly j after the circuit had been closed for
twenty-four hours there was still a decomposition, which con-
tinued, but the action was extremely feeble. Two cells were
allowed to remain arranged in closed circuit for fifteen days,
a third being placed by the side, but with the terminals un-
connected ; at the expiration of this time the rise of liquid in
the tubes was as follows : —

Rise of liquid in cells of closed

circuit, in tubes of
Oxygen . 0*05 cubic inch.
Olefiant gas 0*4

Rise of liquid in cells of de-
tached pair, in tubes of
Oxygen . 0#02 cubic inch.
Olefiant gas 0*3

Rise of liquid apparently due to voltaic action,
In oxygen tubes . . . 0*03 cubic inch.
In olefiant gas tubes . 0*1 •««

These quantities are too small to enable any satisfactory in-
ference to be deduced as to the equivalents of these gases which
contributed to electrolysis; the more so as the rise of liquid
was not quite uniform, and the action due to solution was so
much greater than that due to electrolysis.

I do not feel entitled to draw any other conclusion from
this experiment than that there was a very feeble voltaic cur-

350 Mr. Grove on the Gas Voltaic Battery,

rent produced by these gases ; both the remaining oxygen and
the defiant gas were unaltered in character.

Experiment 11. — Oxygen and carbonic oxide produced no-
table effects upon the iodide, and slight symptoms of decom-
posing water; a few bubbles gathered upon the electrodes of
an interposed voltameter ; the effects continued ; and at the
expiration of fifteen days, the following was the state of the
tubes in two cells, put aside as in the last experiment : —

Rise of liquid in cells of closed
circuit,

cubic inch.
In oxygen tubes . . . 0*12
In carbonic oxide tubes 0*93

Rise of liquid in tubes of de-
tached pair,

cubic inch.
In oxygen tubes . . . 0*02
In carbonic oxide tubes 0*7

Rise of liquid apparently due to voltaic action,
In oxygen tubes . . 0*1 cubic inch.
In carbonic oxide tubes 0*23

Before the battery was charged for this experiment, the
carbonic oxide had been carefully freed from carbonic acid by
caustic potash. After action, the liquid gave a slight precipi-
tate wilh lime-water, showing that carbonic acid had been
produced by the action. In this experiment the rise was more
uniform in the different tubes than in the last, and the action
more decided. The results, although on a small scale, appear
more definite ; thus we get the proportion as 1 : 2*3 ; and as
the combining volumes of oxygen and carbonic oxide are as
one to two, if we add the local action due to the oxygen of
the air in solution, 1 to 2'3 is as near an approximation as can
be expected. Though much superior to olefiant gas, the ac-
tion of carbonic oxide is, however, very feeble when compared
with that of hydrogen.

Experiment 13. — Oxygen and chlorine. Very considerable
action on the iodide at first, but not constant; it abated within
the first hour, and after twenty-four hours the action was ex-
tremely feeble, scarcely perceptible; the water had risen nearly
to the top of the chlorine tubes, but the level in the oxygen
tubes was unaltered. The chlorine was negative to oxygen,
or in other words, the oxygen was in its voltaic bearing to
chlorine as hydrogen to oxygen.

As in this experiment the water level in the oxygen tubes
was unaltered, it appeared that this gas had little to do with
the action, I therefore,

Experiment 14, — Charged the alternate tubes of a battery
with chlorine and dilute sulphuric acid; the amount of action
was much the same as in experiment 13, and equally trans-
itory ; a few gaseous bubbles were perceptible on the plati-
nums in the oxygen cells, but not in sufficient quantity for

Mr. Grove on the Gas Voltaic Battery. 351

examination. It is well known that chlorine of itself will
slightly decompose water, forming hydrochloric acid, and
evolving oxygen, and there is little doubt that the voltaic ac-
tion here observed was due to this. There was no appear-
ance of the platinum having been attacked in several experi-
ments which I made with chlorine. So slight a chemical
action will, however, give rise to voltaic effects, that the ab-
sence of any apparent corrosion is not conclusive. It is stated
by chemists that gaseous chlorine will not attack platinum,
but that it is only when nascent it combines with this metal;
non constat however, that in the gas battery the chlorine at
the initiatory instant of its electro-synthesis may not be in a
state analogous, as to its chemical energies, to that converse
state called nascent, and therefore we cannot venture to nega-
tive the possibility of the platinum being slightly attacked.
This circumstance, added to its extreme solubility and power
of decomposing water, makes chlorine rather an unsatisfactory
element for the class of actions developed by the gas battery.

Solutions of bromine, chlorine and iodine, have been before
experimented on (I believe by Dr. Schcenbein and M. Bec-
querel) as to their voltaic relations, but in examining the vol-
taic relations of bodies in a gaseous state, or to express myself
with more caution, in a state passing from gaseous to liquid,
I tried,

Experiment 15, — One set of tubes charged with gaseous
chlorine, and the alternate tubes with solutions of bromine
and iodine. The chlorine was negative to both, i. e. was to
these as oxygen to hydrogen.

I now tried hydrogen with several gases, but as it was next
to impossible (I found it quite impossible), in experiments on
a large scale, perfectly to exclude atmospheric air from the so-
lution*, voltaic action was produced in every case; and as
with one exception (chlorine) oxygen was the most powerful
electro-negative gas, the action of the atmospheric air entirely
masked any effect which might have been produced by the
other gasesf. I shall, therefore, not go through these expe-
riments in detail, but mention one or two only which appear
interesting, for the reasons which I shall state.

Experiment 16. — Chlorine and hydrogen gave very power-

* Gases will creep by a species of endosmose through water. Some time
ago I kept inverted over water for two months, a vessel divided by a dia-

Khragm of porous ware, on one side of which was oxygen gas, on the other
ydrogen ; the diaphragm was constantly wet from capillary attraction ; at
the end of that period the water had risen considerably, and the gases on
each side detonated.
■| See Postscript.

352 Mr. Grove on the Gas Voltaic Battery.

ful effects, as was expected by Dr. Schcenbein*; water was
decomposed between platinum electrodes by two cells. This
is the most powerful gas battery f, but not very satisfactory,
for the reasons above stated, experiment 13.

Experiment 17. — Hydrogen and carbonic oxide were tried
in order to ascertain their voltaic relations. Hydrogen was
much more electro-positive than carbonic oxide, or rather
formed, with the oxygen of the atmospheric air in solution, a
combination which overpowered the opposite tendency of the
carbonic oxide and air.

Experiment 18. — Chlorine and defiant gas gave a very
feeble effect upon iodide of potassium. After four hours the
liquid in the olefiant gas tubes had not risen more in the closed
circuit than in the detached pair; the chlorine was nearly all
absorbed in solution.

Experiment 19. — Chlorine and carbonic oxide gave very
notable effects; ten cells decomposed water. From the ex-
treme solubility of the former gas, the equivalent relationship
could not be ascertained.

It now occurred to me that as oxygen and hydrogen are
evolved from water by electrolysis, and conversely form water
bv electro-synthesis, so some other gases which are evolved
from certain electrolytes by voltaic action, might, when ar-
ranged as a gas battery with the electrolyte from which they
are evolved, give rise to a current, although they would not
do so when arranged in circuit with a different electrolyte.
To test this view I tried,

Experiment 20, — Oxygen and deutoxide of nitrogen in al-
ternate tubes of the gas battery, with dilute nitric acid ; the
effects were however precisely similar to experiment 8, viz. a
very feeble action for a few minutes, then a cessation, and no
continuous chemical action.

Experiment 21. — For the same reason oxygen and nitrogen,
with solution of sulphate of ammonia, were tried ; this arrange-
ment produced at first a slight effect upon the iodide, which
soon ceased, and after several clays there was no more rise of
liquid in any cell of the closed circuit than in the detached

* See his letter, Phil. Mag., March 1843.

+ Chlorine, in its voltaic relations, maybe considered as the converse of
zinc, both decomposing water, but the one liberating oxygen, the other hy-
drogen ; thus a tube of the gas battery charged with chlorine, and having
acidulated water as an electrolyte, and zinc as a positive clement, forms a
combination of which one pair will decompose water. I have tried to
render this combination practically useful, by charging the negative cell of
a nitric acid battery with peroxide of manganese and muriatic acid, but the
supply of chlorine thus obtained is insufficient for quantitative voltaic
effects, though the intensity is great.

Mr. Grove on the Gas Voltaic Battery. 353

cell ; the rise of liquid in both was very trifling indeed (about
0*01 cubic inch), and had evidently nothing to do with voltaic
action. In. this experiment, and in every experiment that I
have tried, I have perceived a trifling action for the first few
minutes. This I should have attributed to accidental causes,
such as slight impurities in the gases, slight metallic deposits
on the plates, &c, but that it is always in the direction which
theory would indicate. Thus in the present experiment, the
appearance of iodine indicated oxygen to have the same voltaic
relation to nitrogen as it has to hydrogen. This temporary
effect, therefore, appears to me analogous to that action called
by continental experimentalists polarization, an apparent ten-
dency to action, i. e. an arrangement of molecules preliminary
to electrolysis, but incapable of producing a continued cur-
rent. In this and many other experiments with the gas bat-
tery I have observed this effect, but have never been able to
produce any chemical change or electro-synthetic absorption
of nitrogen.

Experiment 22. — As oxalic acid when electrolysed evolves
at the anode a mixture of oxygen and carbonic acid, and at
the cathode hydrogen and carbonic oxide; for the reasons
above stated, 1 charged a gas battery with carbonic acid and
carbonic oxide in the alternate tubes, and with oxalic acid as
an electrolyte ; a slight effect was produced, the carbonic oxide
being to the carbonic acid as hydrogen to oxygen ; but the
current was evidently due to the atmospheric air in solution
combining with the carbonic oxide; this I proved by some of
the test experiments before mentioned, which I need not re-
capitulate.

Experiment 23. — Hydrogen, nitrogen, and sulphate of am-
monia. This combination also gave effects with which the
nitrogen appeared to have nothing to do, this gas being per-
fectly unaffected ; I tried other experiments on this point, but
they all led to the same conclusion, viz. that my idea of reali-
zing a voltaic action by conversion of the ordinary effects of
electrolysis was erroneous. It may be that the above gaseous
products of electrolysis are secondary, and that water is the
only electrolyte in these cases ; but for this, as for many other
theoretical questions, there are so many arguments pro and
con, that it is not worth while to dilate on them unless they
can be shown to lead, or to be likely to lead, to some new
valuable facts or natural relations.

Reviewing the above experiments, it appears that chlorine
and oxygen, on the one hand, and hydrogen and carbonic
oxide, on the other, are the only gases which were decidedly
capable of electro-syntheticallv combining so as to produce a

Phil. Mag. S. 3. Vol. 24. No. 160. May 184-4. 2 A

354- Mr. Reuben Phillips on the Elasticity of Gases.

voltaic current*. I should perhaps except olefiant gas, which
appears to give rise to a continuous though extremely feeble
current; and the vapours of bromine and iodine, were they
less soluble, would probably also be found efficient as electro-
negative gases.

[To be continued.]

LI. Some Remarks on the Elasticity of Gases.
By Reuben Phillips.

To Richard Taylor, Esq.
Sir,
T^HE pressure exercised by a gaseous volume on surround-
ing matter, as measured by its pressure on a small square
unit, has been found to vary as the volume, or that the vo-
lume, plus the pressure on the square unit, is always equal,
the ponderal quantity of gaseous matter being of course con-
stant. Now, if a gaseous volume may be represented by the
symbol (vy)% in which y is the distance between the atomic
centres, and v the number of times y is contained in one side

of the cube (vy)s, then Mp- = —^ — -^-9 z being any posi-
tive or negative quantity, but so taken as not to render the
fraction 0, or OC; therefore the gaseous volume varies as the
cube of y; but the pressure also varies as the volume, and
therefore as y3. If the pressure be assumed to proceed from
the mutual repulsion of the gaseous particles, it is hereby
shown that such repulsion varies as the cube of the distance
between the atomic centres. This seems to be an exception
to the general law, whereby forces emanating from a centre
vary as the square of their distance from that centre, which
appears to point out as a fact, that gaseous repulsion does not
solely proceed from centres.

I remain, Sir,
Your most obedient Servant,
Monmouth Street, Topsham. REUBEN Phillips.

LI I. On some new Species of Biliary and Intestinal Concre-
tions. By Thomas Taylor, Esq.
To Richard Taylor, Esq.
Dear Sir,
CEVERAL statements having appeared in the continental
*** journals with regard to the composition of some new
species of biliary and intestinal concretions, I have received
permission from the Museum Committee of the Royal College
of Surgeons to state, that in the second and third parts of the
* See Postscript.

Mr. T. Taylor on Biliary and Intestinal Concretions. 355

Catalogue of the Calculi and other Concretions, which will
shortly be published, the following facts will be shown : —

1. That the lithofellinic acid calculus, described by Profes-
sors Goebel and Wohler, Ann. derPharm. for 1841, b. xxxix.,
and Gotting. Geleltr. Anz. for the same year, is not a new
species of calculus, but is identical in composition with the
calculus described and figured by Fourcroy and Vauquelin
in the first volume of the Ann. der Museum National as " re-
sine animate bezoardique." Also that it is not a biliary calcu-
lus, or in any way connected with the biliary secretion, as its
name would imply, but that it is derived from the resinous
juices contained in the plants, &c. on which the species of wild
goat, termed by the Persians Pasen, browses. This view of
the origin of these bodies is advocated by Kaempfer in his
Amcenitates Exotica, and its correctness will be proved on
chemical and other grounds.

2. That several intestinal concretions have been discovered
consisting of the insoluble acid obtained by Braconnot from
the infusion of gall-nuts, and termed by him ellagic acid. The
constituent of these concretions has been described by John,
Chem. Sehr. 3. 38, under the name of Bezoarstoffl It forms
also the ligniform matter of Berthollet, " Holzartige Materie-"
and I have also no doubt that it is the ■peculiar acid from
the oriential bezoar, described by M. Lippowitz in Simons's
Beitr'dge zur phys. et pathol. Chemie, b. i. p. 463, and termed
by him bezoaric acid.

Oxalate of Lime. — In the first part of the Catalogue, pub-
lished in 1842, p. 75, I alluded to the fact of large concretions
of this salt being occasionally found in the intestines of herbi-
vorous animals ; these have since been described as a new spe-
cies by M. Guibourt, in the Joum. de Pharm. et de Chimie
for February 1843.

Biliary Calculi. — In addition to the stearate of lime calcu-
lus, already described in the Phil. Mag.*, I have to announce
the existence of another species, which resembles in most of
its chemical habitudes the colouring matter of the bile (Chole-
pyrrJiine, Berz.), but which is not converted into Gallengrun
by solution in potash and precipitation by muriatic acid.

Urate of Potash. — Two of these calculi, the discovery of
which was alluded to in the preface to the first part of the Ca-
talogue, have been submitted to a quantitative analysis. One
contained above 10 and the other above 13 per cent, of potash
in combination with uric acid.

Intestinal Concretions consisting of Vegetable Hairs. — Dr.
Wollaston first showed that the greater number of the human
* S. 3. vol. xvii. p. 8.
2 A 2

356 Sir David Brewster on the Law of Visible Position

intestinal concretions consisted of the small setae attached to
the coreopsis of the seed of the oat. I have discovered in the
Museum several concretions from the lower animals, consist-
ing also of the vegetable hairs from the different parts of
plants.

The nature of the so-called lithofellinic acid calculus, for
which I shall propose the name of resino-bezoardic acid, and
also of the oxalate of lime concretion, was described in a report
read before the Committee in January 1841, but the statements
of Professor Goebel, and other eminent foreign chemists, have
compelled me carefully to re-examine these calculi.

I trust soon to have an opportunity of sending you in detail
the results of my investigation of this subject, but until the
Catalogue is published the Committee are desirous that only
the above brief notice of a few of the leading facts should
appear.

I remain, my dear Sir,

Yours very truly,

91 Fleet Street. Thomas Taylor.

LIII. On the Law of Visible Position in Single and Bi-
nocular Visioft, and on the representation of Solid Figures
by the union of dissimilar Plane Pictures on the Retina*. By
Sir David Brewster, K.H^D.C.L., F.R.S., and V.P.R.S.
Edin. f

TN the course of an examination of Bishop Berkeley's New
Theory of Vision, the foundation of the Ideal Philosophy,
I have found it necessary to repeat many old experiments, and
to make many new ones, in reference to the functions of the
eye as an optical instrument. I had imagined that many points
in the physiology of vision were irrevocably fixed, and placed
beyond the reach of controversy ; but though this supposition
may still be true in the estimation of that very limited class of
philosophers who have really studied the subject, yet it is mor-
tifying to find that the laws of vision, as established by expe-
riment and observation, are as little understood as they were
in the days of Locke and Berkeley. Metaphysicians and phy-
siologists have combined their efforts in substituting unfounded
speculation for physical truth; and even substantial discove-
ries have been prematurely placed in opposition to opinions
of which they are the necessary result.

In prosecuting this subject, my attention has been particu-

* A second paper on this subject will appear in an early Number of this
Journal.

f From the Transactions of the Royal Society of Edinburgh, vol. xv.
part 3; having been read January 23 and February 26, 1843.

in Single and Binocular Vision. 357

larly fixed upon the interesting paper of my distinguished
friend Professor Wheatstone, On some remarkable and hi-
therto unobserved Phaenomena of Binocular Vision*. It is
impossible to over-estimate the importance of this paper, or to
admire too highly the value and beauty of the leading disco-
very which it describes, namely, the perception of an object of
three dimensions by the union of the two dissimilar pictures
formed on the retinae : — but, in seeking an explanation of this
curious phenomenon, and in applying it to explain phaeno-
mena previously known, Mr. Wheatstone has adduced expe-
rimental results, and drawn conclusions which stand in direct
opposition to what was best established in our previous know-
ledge. Before entering, however, upon this branch of the
subject, I must first explain the law of visible direction, and
the phaenomena of ocular parallaxes.

1 . On the Law of Visible Direction in Monocular Vision.

Several philosophers had hazarded the opinion, that every
external visible point is seen in the direction of a line passing
from its picture on the retina through the centre of the eye
considered as a sphere ; while others maintained that every
such point was seen in the direction of the refracted ray by
which its image was formed.

The celebrated D'Alembert, in his Doutes sur differents
questions d'Optique, maintains that the action of light upon the
retina is conformable to the laws of mechanics; and he adds,
that it is difficult to conceive how an object could be seen in
any other direction than that of a line perpendicular to the
curvature of the retina at the point where it is really excited.
He then investigates, mathematically, how the apparent mag-
nitudes of objects would be affected, on the two suppositions
that the line of visible direction coincides either with the re-
fracted ray, or with a line perpendicular to the retina at the
point of excitement. On the Jirst of these suppositions, he
finds that the apparent magnitude of small objects would be
increased about Tyth, and on the second supposition, a little
more than ^, or y^8/^. This last result is, as D'Alembert
justly remarks, so contrary to experience, that we cannot sup-
pose vision to be thus performed, however natural the suppo-
sition may appear. " In the direction of what line, then," he
adds, " do we perceive objects, or visible points, which are not
placed in the optical axis? This is a point which it appears
very difficult to determine exactly and rigorously. As expe-
rience, however, proves that objects of small extent, which are

* Philosophical Transactions, 1838, p. 371. [Noticed in Phil. Mag.
S. 3. vol. xiii. p. 461.]

358 Sir David Brewster on the Law of Visible Position

within the range of our eyes, do not appear sensibly greater
than they are in reality, it follows, that the visible point which
sends a ray to the cornea, is seen sensibly in its place, and
consequently in the direction of a line joining the point itself
and its image on the retina. But why," D'Alembert adds,
" is this the case ? It is a fact which I will not undertake to
explain*."

When we consider the data from which D'Alembert has
deduced the preceding results, it is not easy to account for his
having abandoned the inquiry as a hopeless one. He employs
the dimensions of the eye as given by Petit and Jurin, and he
assumes Jurin's index of refraction for the human crystalline
lens, though it is almost exactly the same as that of an ox, as
given by Hawksbee. These, indeed, were the best data he
could procure; but he should have inquired if the most pro-
bable law of visible direction was compatible with any other di-
mensions of the eye, and any other refractive powers of the
humours which were within the limits of probability; and
above all, he ought to have examined experimentally the truth
of his fundamental assumption, that visible points are really
seen in their true places when they are not in the axis of vision.

Now it is quite certain that these points are not seen in their
true direction, and that there is an ocular parallax, which is
the measure of the deviation of the visible from the true direc-
tion of objects. This parallax is nothing in the axis of the
eye, and it increases as the visible point is more and more
distant from that axis; and hence it follows, that, during the
motion of the eyeball, when the head is immoveable, visible
objects not only change their place, but also their form.

Had the eye consisted of only two concentric coats, a cornea
and a retina, filled with a homogeneous fluid, vision would
have been performed by centrical pencils ; — the visible and
the true direction of points would have coincided, and objects
would have changed neither their form nor their position du-
ring the motion of this hypothetical eyeball round the common
centre of the two coats. But as such an eye could not have
afforded sufficiently distinct vision, the introduction of the
crystalline lens became necessary ; and it is owing to the se-
condary refractions at its surfaces and within its mass of vari-
able density, that the parallax of visible direction is produced.

The following experiment will establish the existence, and
explain the nature of this parallax. Let M N, fig. 1, be the
eyeball, C the centre of curvature of the retina, and also the
centre of motion of the eyeball. Having placed an opake
screen S several inches from the eye, till its inner edge just
* Opuscules Mathematiques, torn. i. mem. ix. p. 266.

in Single and Binocular Vision. 359

eclipses a luminous object A, look away from the screen, and
the object A will appear. Keeping the head steady, place

Fig. 1.

another screen S'* so that, when viewed directly, it does not
eclipse another luminous object B, the line C S' B just grazing
the outer edge of B. When the screens and luminous objects,
therefore, are so arranged that A is invisible when the axis of
the eye is directed to S or to A, and B visible when the axis
of the eye is directed to S' or B, — then by turning the eye
from A to B, A will appear, and B will disappear, exhibiting
the curious effect of an invisible body appearing by looking
away from it, and of a visible body disappearing by looking
at it !

Had the eyeball M N been our hypothetical one, these
effects would not have been produced. All objects, near and
remote, would have retained their relative positions and mag-
nitudes during its rotation.

Hence it follows, that we are not entitled to reject any law
of visible direction, because it gives a position to visible ob-
jects different from their real position.

Having removed this difficulty, I proceeded to examine the
other data of D' Alembert. Making the eyeball and the retina
spherical, he assumes that the centre of the latter is equidistant
from the foramen centrale of the retina, and the centre of the
crystalline lens. This, however, is far from being the case.
M. Dutour, and Dr. Thomas Young, have made the centre
of curvature of the retina coincident with the centre of curva-
ture of the spherical surface of the cornea, as in our hypothe-
tical eye; and this centre, in place of being almost half-way
between the apex of the posterior surface of the lens and the
foramen centrale, is actually almost in contact with the latter !
The dissections of Dr. Knox and Mr. Clay Wallace of New

* The two screens S, S' may be the opposite edges of a triangular notch
in a card held in the hand.

360 Sir David Brewster on the Law of Visible Position

York, give similar results. When we add to these considera-
tions the fact that the refractive power of the crystalline lens
assumed by D' Alembert is nearly triple of what it really i s,
we are entitled to reject the results of his calculations.

Assuming, then, the most correct anatomy of the eye,
namely, that according to which the cornea and the retina are
concentric, it is obvious that if there was no crystalline lens,
. pencils, incident perpendicularly on the cornea, would pass
through the common centre, and fall perpendicularly upon
the retina. Hence, in this case, the line of visible direction
would coincide with the line of real direction, and also with
the incident and intromitted ray. Now, the refractions at the
crystalline are exceedingly small, and, at moderate inclinations
to the axis, the deviations from the preceding law are very
minute. At an inclination of 25° or 30°, a line perpendicular
to the point of impression on the retina passes through the
common centre already referred to, and does not deviate from
the line of real visible direction more than half a degree, a
quantity too small to interfere with the purposes of vision.
The deviation, of course, increases with the inclination ; but
as there is no such thing as distinct vision out of the axis, and
as the indistinctness increases with the inclination, it is impos-
sible to ascertain, by ordinary observation, that any deviation
exists. Hence the mechanical principle of D' Alembert, which
he himself has rejected, and the law of visible direction, which
I have established, are substantially true. As the Almighty
has not made the eye achromatic, because it was unnecessary,
so He has, in the same wise ceconomy of His power, not given
it the property of seeing visible points in their real direction.

Had it been necessary to make the visible ray coincident in
direction with the incident ray, it might have been effected by
giving such a form and variable density to the crystalline lens
as to make the ray which it refracted cross the axis of vision
at the centre of curvature of the retina ; and if the crystalline
lens were such that this crossing point was variable, this varia-
tion might have been compensated by making the retina
spheroidal, with a variable centre of curvature.

That a visible point is seen in the direction of a line per-
pendicular to the surface of the retina at which the image of
the point is formed, may be established experimentally in the
following manner. Having expanded the pupil by belladonna,
look directly at a point in the axis of the eye. Its image will
be formed by a cone of rays variously inclined from 85° to
.90° to the surface of the retina. While the point is distinctly
seen, intercept all these different rays in succession, and it
will be found that each ray gives vision in the same direction,

in Single and Binocular Vision. 36 1

the visible point retaining its position. Hence it follows, that
on the part of the retina in the axis of vision, all rays, however
obliquely incident, give the same visible direction perpendi-
cular to the surface of the membrane. That the same pro-
perty is possessed by every other part of the retina cannot be
doubted, and may be proved by direct experiment.

Although D' Alembert states it as unquestionable, that when
the visual ray is in the axis of vision, or the optic axis, and
passes to the retina without refraction, the point which emits
it will be seen in the direction of a line passing from its image
to the visible point; yet, after he has found that his mecha-
nical principle is not correct, he gives loose reins to his scep-
ticism, and maintains the extraordinary paradox, that objects
even which are placed in the optical axis are not always seen
in this axis. The following is the argument he employs, which
I shall give in his own words.

" If we direct the two optic axes A E, B E, fig. 2, towards

Fig. 2.

a star E, it is certain that this star appears much nearer to us
than it really is : it is true that we estimate its distance only
in a very imperfect and vague manner ; but it is not less cer-
tain that this distance perceived, whether apparent or pre-
sumed, is greatly below the real distance. If, then, we see the
star in each of the optical axes A E, B E, we should see it in
each of these axes in the points e, e, which are incomparably
nearer A and B than E. Thus we should see two stars e, e,
and their apparent distance e e would be nearly equal to A B.
Observation, however, proves that we see only one star, and
this star is seen nearly at the middle point e of the line e e in
the direction of lines As, B e, different from the optic axes.
It is true that these lines, though really different from the optic
axes, deviate from them but very little, but still they do differ
from them ; and this experiment is sufficient to prove that
objects which are at a considerable distance from the eye are not
seen exactly in the optical axis, even when we look at them di-
rectly.

" Whence, in general, nothing is less certain than this

562 Sir David Brewster on the Law of Visible Position

common principle in optics, that objects are seen in the direc-
tion of the ray 'which they send to the eye*."

It is almost impossible to believe that D'Alembert is serious
in maintaining these doctrines. The major proposition of his
syllogism is absolutely incorrect. It is not true that we see
the star E nearer than it is. The eye does not see distances
directly : the mind only estimates them, and, according to its
means of judging, it forms a right or a wrong opinion. The
second proposition is equally incorrect. We do not see the
star along the lines As, Be. We see it along the lines A E,
B E, at the very place where it is, and whether we consider it
nearer or more remote than it is, — whether we think that it
touches our eye, or exists at the remotest verge of space, —
the position of the optical axis of each eye remains as before,
and our vision of the star is not affected by the truth or false-
hood of our judgement.

2. On the Law of Visible Direction in Binocular Vision.

In admitting the correctness of the law of visible direction
in monocular vision, which I have endeavoured to establish in
the preceding section, Professor Wheatstone justly remarks,
"that the result of any attempt to explain the single appear-
ance of objects to both eyes, or, in other words, the laiv of vi-
sible direction for binocular vision, ought to contain nothing
inconsistent with the law of visible direction for monocular
vision f-" Properly speaking, however, there is no such thing
as a law of visible direction in binocular vision, because there
is no such thing as a centre of visible direction, or a line of
visible direction in binocular vision. When we see an object
distinctly with both eyes, it is actually seen in two directions,
and the point where these directions intersect each other de-
termines the visible place of the object. But if we follow Mr.
Wheatstone in considering such a law as equivalent to the
law which regulates "the single appearance of objects to both
eyes," we can readily deduce it as a corollary from the law
in monocular vision. A visible point is seen single with two
eyes only when it is at the intersection of its lines of visible
direction as given by each eye separately. It is obvious that
this law does not harmonize with the doctrine of correspond-
ing points, or with the binocular circle of the German phy-
siologists. It is, however, rigorously true ; for no philosopher
can adopt the monstrous opinion that the functions and laws
of vision which belong to each eye, acting separately, are sub-
verted when they act in concert. Hence it is obvious that

* Ojiusculcs Mathematiqucs, torn. i. mem. ix. § iv. p. 273-4.
f Philosophical Transactions, 1838, p. 388.

in Single and Bi?iocular Vision. 363

the single vision of points with two eyes, or with two hundred
eyes, is the necessary consequence of the convergency of the
two, or the two hundred, lines of visible direction to the same
point in absolute space ; and although we think that objects ap-
pear single with both eyes, yet it is only the points to which the
optic axes and the lines of visible direction converge that are ac-
tually seen single, and the unity of the perception is obtained by
the rapid survey which the eye takes of every part of the object.
The phenomenon of an erect object from an inverted picture
on the retina, which has so unnecessarily perplexed metaphy-
sicians and physiologists, is a demonstrable corollary from the
law of visible direction for points. The only difficulty which
I have ever experienced in studying this subject, has been to
discover where any difficulty lay. An able writer, however, in
a recent number of Blackwood's Magazine*, in discussing the
Berkleyan theory of vision, has started a difficulty of a very
novel kind, and has called upon me personally to solve it.
Were this the proper place for such a discussion, I should
willingly enter upon it ; but I must content myself with stating,
that the doctrine which the very ingenious author calls the
ordinary optical doctrine, was never maintained by any optical
writer whatever, and that the doctrine which he substitutes in
its place is that which all optical writers implicitly adopt,
though they have thought it too elementary to require illus-
tration. A visible point which throws out two separate par-
ticles of light, an upper and an under, will be inverted on the
retina, but a smaller visible point which throws out only one
particle of light, cannot be inverted, because inversion implies
a change in the relative position of two visible points.

3. On the Vision of Objects of Three Dimensions.

(1.) By Monocular Vision. — If we look with one eye at a
solid body, for example a six-sided pyramid with its apex di-
rected to the eye, and uniformly illuminated, we recognise at
a single glance that it is not a drawing of the pyramid. When
the eye adjusts itself to distinct vision of its apex, all the more
distant parts are seen indistinctly, but the eye quickly surveys
the whole, adjusting itself to distinct vision of its base and of
its edges, and by these successive efforts, at one time contract-
ing the pupil and the eyebrows to see the near parts^ and ex-
panding them to see the more remote ones, it obtains a know-
ledge of the relative distance of its different parts. The vision
of the pyramid thus obtained is nearly perfect. There is no
inequality of illumination produced by the act of single vision ;
and there is no flickering in the outlines of the figure. The
* June 1842, vol. li. p. 830.

364 Sir D. Brewster on the Law of Position in Vision.

only apparent imperfection is, that when we see one point very
distinctly we do not see the other parts with equal distinctness ;
but this imperfection is unavoidable in vision, whether with
one or two eyes; and, in place of being a defect, is the very
means by which we judge of the relative distance of its parts.
If we saw all its lines and parts with equal distinctness, with-
out moving the eyeball, or without altering the mechanism for
its adjustment, we should not have been able to distinguish the
pyramid from its projection upon a plane surface.

Hence we draw the conclusion that the vision of bodies of
three dimensions with one eye is perfect.

(2.) By Binocular Vision. — If we now place the pyramid
before both eyes, so that the pictures of it on each retina are
nearly similar, the one being the reflected image of the other,
we shall see the pyramid with great distinctness. It will ap-
pear more luminous with the two eyes, and if the observer
wished to estimate the distance of its apex, or any other point
of it, from himself, the convergency of both eyes to that point
would enable him to form a more correct judgement than with
a single eye. These, doubtless, are advantages, but they do
not in the least degree improve our vision of the pyramid,
which is independent of them. More light may injure vision
as well as improve it; and if we could project a foot-rule from
each eye, and read upon it the distance of every part of the
pyramid, the vision of it would not in the slightest degree be
affected. May we not add also, that the intromission of scat-
tered light through two eyes in place of one, and the possible
dissimilarity, however small, between the curvatures and den-
sities of their humours, which would give rise to two pictures
of different magnitudes, would entitle us to give the preference
to single vision, in reference to its power of giving us a distinct
view of objects of three dimensions ?

Hence, we conclude, that when the pyramid is placed in a
position of symmetry between the two eyes, binocular is not
superior to monocular vision.

But if the pyramid is so placed that the left eye sees only
four faces of it, while the right eye sees all the six, then the
monocular vision of the pyramid is more distinct than the bi-
nocular one. The vision of faces 1, 2, 3, and 4 is sufficiently
distinct with two eyes ; but the faces 5, 6, being seen only with
one eye, are less luminous than the other faces, and as the
optic axes do not perform their functions with the same accu-
racy when the object to which they are directed is visible only
to one eye, the part of the object seen by single vision will not
unite with that seen by double vision ; and, in the case of the
pyramid, we shall observe its apex actually projecting upon

Mr. J. Napier on the Solubility of Metals, fyc. 365

the faces 5, 6 of the pyramid, and destroying the symmetry
of the picture. When all the faces but No. 6 are seen by the
left eye, vision is still unsatisfactory with both eyes, and yet
more so when only three of the faces are seen by the left eye.

Hence we conclude that, in these cases, binocular is inferior
to monocular vision.

Let us next suppose that the object viewed is a table knife,
so placed that, when the back of it is towards the observer,
the left side of the blade is seen by the left eye, and the right
side of the blade by the right eye. As the back is seen by
both eyes, the picture presented to the mind is a compound
of one double and two single sensations, and, consequently, a
very unsatisfactory representation of the object.

Hence we conclude that, in this case, binocular is still more
inferior to monocular vision.

These results stand in direct opposition to those given by
Professor Wheatstone, who considers it an established fact,
" that the most vivid belief of the solidity of an object of three
dimensions arises from two different perspective projections of it
being simultaneously presented to the mind." Before entering,
however, upon this branch of the subject, I must examine
Mr. Wheatstone's views respecting the binocular vision of
figures of different magnitudes.

[To be continued.]

LIV. On the Solubility of the Metals in Persulphate and Per-
chloride of Iron. By Mr. James Napier*.

THE following observations have been lying in nn unfi-
nished state for some months past, in hopes that time
would allow me to make more investigations into some of the
phaenomena developed ; but owing to urgent duties, altogether
apart from such investigations, I have little hopes of being
able to fulfil these intentions ; I have therefore collected them
together, in hopes that it might attract the attention of some
one more qualified to give them that investigation which their
singularity seems to deserve.

I may be allowed, in the first place, to relate the circum-
stances which led me to the observations which follow. Hear-
ing of the great quantity of water which is constantly issuing
from the Pary's Mines, Anglesea, impregnated with copper,
and the great expense of obtaining this copper, I thought it
probable that it might be extracted by means of a galvanic
current, or what is known as the electrotype process. For

* Communicated by the Chemical Society ; having been read November
7, 1843.

366 Mr. J. Napier on the Solubility of the

the purpose of trying experiments upon this subject, I was
kindly favoured with a quantity of the water, with the follow-
ing details : — Quantity of water issuing from the mines yearly,
700,000,000 gallons ; this is collected in pits, into which is put
old iron, which precipitates the copper. The average pro-
duct of copper is from 55 to 60 tons; the iron consumed in
obtaining this is 600 tons. The copper found in these waters,
as indicated from the precipitate obtained, varies from 4 to
30 per cent., according to the wetness of the season ; the sam-
ple I procured was during the dry season, and consequently
rich in copper; its specific gravity was 1*05.5 at 60° F. The
solid contents of one gallon weighed 4960 grains, which gave
peroxide of iron 1680 grains, oxide of copper 80 grains, sul-
phuric acid 3040 grains, muriatic acid 38 grains, and 122
grains of earthy matters, which were not examined. The iron
existed in the water as the persulphate. My first operation
was one I had found to answer in analysing copper ores,
namely, wrapping a strip of brown paper round a piece of
iron, attaching this to a piece of copper, and immersing them
both in the solution of the copper ore, in muriatic acid, to be
examined ; but I found that the first action which took place
was the complete reduction of the persalt of iron to the state
of protosalt, at the expense of the copper pole: after which
the electric current began to effect its object, the copper being
deposited, but from the copper which had been dissolved
having also to be deposited, the consumption of iron was 658
grains, while the actual increase in the weight of the copper
pole was only 64 grains, the quantity of copper originally held
in solution. The reaction which took place may be expressed
as follows : —

1/?ork • c firon 582*7"

1680 grains of . _-„ '

•5 c . J iron 582*7 i r*

peroxide of iron<( ^ > protosulphate of iron.

composed of I ox^Se x I

Loxygen 171 '5.

oxygen 171*5V
2568 grains of fac!1} ^6*0 f

sulphuric acid. 1 acK *&*°J

^ Lacid 856*01 i u <. e

Copper pole. copper 690*7 j SulPhate of C0PPer'

giving 690*7 grs. + 64 grs. to be deposited by the electric cur-
rent. Different arrangements of batteries were tried; platinum,
silver and lead were also substituted for the copper, but in no
case was a deposit obtained from the water until the iron was
first brought into the state of a protosalt; but when this was
effected, I obtained by the method first described 63 grains of
copper by the loss of 58 grains of iron.

Metals in Persulphate and Perchloride of Iron. 367

During these experiments I found that silver, tin, lead, an-
timony, bismuth, cobalt, nickel, and several other metals were
very soluble in neutral persalts of iron, reducing it to the
state of a protosalt. In order to repeat these experiments, I
prepared some perchloride of iron in the following manner,
adding to the boiling solution of the sulphate as much nitric
acid as was necessary to peroxidize the iron, then precipitating
by ammonia, washing this well with hot water, and dissolving
with hydrochloric acid, evaporating nearly to dryness, and
adding a quantity of distilled water. The persulphate used
was obtained as a dry white powder ; both salts were neutral.

I was aware that Professor Fuchs had recommended the
boiling of a piece of clean copper in perchloride of iron as a
means of ascertaining the quantity of iron in an ore of that
metal, and also to ascertain the amount of copper in certain
copper ores. For iron ores I have found great difficulty in
obtaining uniform results, from the great difficulty of knowing
the exact period at which the iron is all reduced to the proto
state, for the copper put in continues to dissolve until the
chloride is all converted into a subchloride; this result is
effected, however, much more rapidly when the iron salt is
neutral than when it contains free acid, a condition specially
recommended by Fuchs.

The most uniform results are obtained by allowing the
copper to remain until the solution becomes colourless ; on
diluting with cold water, the whole of the copper is precipi-
tated as a white powder ; the clear solution, if the process is
completed, will contain no copper, when there will be two
equivalents of copper dissolved from the metal for every equi-
valent of peroxide of iron formerly in the solution. It occa-
sionally happens, however, when neutral salts of iron are used,
that the copper becomes encrusted with a white deposit, upon
which crystals of the subchloride of copper collect, and thus
protect it from further action ; this is prevented by boiling,
or taking out the copper, removing the crust, washing it, and
putting it into the solution again, when the action goes on as
before. When the persulphate of iron is used for this pur-
pose instead of perchloride no subsalt is formed, and the
result is uniform, one equivalent of copper being dissolved
for every equivalent of peroxide of iron present in the solu-
tion.

I may mention one especial application of the solubility of
copper in perchloride of iron, namely, the dissolving copper
from the surface of silver, such as copper that has been used
as a mould in which silver has been deposited ; when this so-
lution becomes saturated with copper, a little ammonia added

368 Mr. J. Napier on the Solubility of the

precipitates the iron as a peroxide and combines with the
copper, forming a soluble double chloride, which may be im-
mediately separated by filtration and the precipitate washed,
the peroxide of iron again dissolved in hydrochloric acid is
fitted for a renewal of the same operation. I may here men-
tion, that if, previous to adding the ammonia, there be a little
perchloride of iron put into the mixture of subchloride of cop-
per and protochloride of iron, an immediate change is effected,
the colour of the solution becomes green, and on adding am-
monia to this, both copper and iron are precipitated.

Persulphate of iron cannot be used for the purpose of dis-
solving copper from silver, both from the easy solubility of
silver in solutions of this salt, and also from a peculiar de-
structive action which it has upon alloyed silver. Standard
silver is completely destroyed. I have used thin sheets,
weighing from 60 to 70 grains, and when only 4 grains were
apparently dissolved the remainder had been so much affected
that it crumbled between the fingers like a dried leaf.

When silver is put into a solution of persulphate of iron an
immediate action takes place, a yellowish cloud begins to form
in the solution; if heated the action is much more rapid, a
yellow oxide of iron forming upon the sides of the vessel, and
there is also a brown precipitate deposited ; the iron in the
solution is converted into the proto state, shining particles of
metallic silver float through the solution, and sulphate of sil-
ver crystallizes on the vessel, but in no case did I find an
equivalent of silver for the equivalent of peroxide of iron ; by
slow evaporation the solution yielded crystals of protosulphate
of iron and sulphate of silver.

Tin is very easily dissolved in both the persulphate and per-
chloride of iron, completely reducing them to the proto state.
When the solution is cold this is effected in about an hour;
when hot, in a few minutes; the iron is reduced to the proto
state when only half an equivalent of tin is dissolved for every
equivalent of peroxide ; my first impression was, that the first
atoms of protosalt of tin formed reduced a corresponding atom
of peroxide of iron, and was converted into a persalt; but sa-
turating with ammonia, and adding it in great excess, the pre-
cipitated oxide of tin was not redissolved, and had every other
character of a protosalt. Whether this was owing to the for-
mation of a bisulphate or bichloride of' tin, I did not ascertain ;
but by boiling or long standing there is an equivalent of tin
dissolved for every atom of perchloride of iron, but I did not
obtain the same result in the persulphate.

Cadmium is very soluble in persalts of iron ; in the persul-
phate an equivalent of cadmium is dissolved for the equivalent

Metals in Persulphate and Perchloride of Iron. 369

of persulphate of iron ; but in perchloride of iron 2 equivalents
of cadmium are dissolved for every equivalent of perchloride
of iron, forming, as in the case of copper, a subchloride, which
was not precipitated by the addition of water.

Lead is also dissolved in persalts of iron, reducing a portion
of the iron to the state of a proto salt ; the lead becomes co-
vered with a thin crust of sulphate or chloride, which seems
to protect it from further action; when the iron solution is
boiled with the lead much more is dissolved, and a precipitate
of peroxide of iron collects at the bottom. This action of iron
on lead may account for the rapid destruction of leaden tanks,
noticed by Mr. West at the last Meeting of the British As-
sociation, that when spring water, which had been running
into a lead tank for many years without the slightest action
upon the lead, was conveyed through iron pipes to the tanks,
the tanks were destroyed in six years.

Antimony is not very soluble in persulphate of iron even
when heated, but it is very soluble in perchloride of iron when
hot, reducing the iron to a protochloride in a short time, the
solution becoming of a light brownish colour. I found that
if kept boiling slowly for a long time the antimony loses an
equivalent of metal for every equivalent of peroxide of iron,
giving us the idea of the existence of a compound of antimony
with chlorine of one to one. This solution was not examined
further than by dilution with water, which precipitated almost
all the antimony as a white powder, undergoing the usual
changes of common chloride, except when the dried precipi-
tate was boiled in nitric acid, in which it dissolved with the
evolution of nitrous gas.

Arsenic is very soluble in perchloride of iron, reducing the
iron to the state of protochloride, losing also with long boil-
ing an equivalent of metal for every equivalent of peroxide of
iron in the solution ; but this result is not obtained without
long boiling.

Bismuth is very soluble in perchloride of iron, slightly in
persulphate ; the perchloride is completely reduced to the
state of protochloride, a full equivalent of metal being dis-
solved for the peroxide of iron present ; this is wholly preci-
pitated by dilution.

Cobalt is very soluble in perchloride of iron, reducing it
completely, changing the solution to a pink colour ; the co-
balt salt formed crystallizes from this solution very easily.

Nickel is also soluble in perchloride of iron, giving a pre-
cipitate of brown oxide of iron; the solution becomes green,
containing protochloride of iron and nickel ; a portion of the
nickel is precipitated as a fine white powder by dilution.

Phil, Mag. S. 3. Vol. 24. No. 160. May. 1844. 2 B

370 Mr. J. Napier on the Solubility of the Metals, §c.

Platinum in persulphate and perchloride of iron produced
no change, neither lost anything in weight.

Gold boiled for a long time in perchloride of iron in two
experiments lost 0*2 and 0*3 of a grain. In both these in-
stances beautiful crimson-red crystals, in perfect octahedrons,
were obtained, adhering to the metal and also to the con-
taining vessel. I did not try whether they contained any
gold. These results were only obtained twice in six different
trials ; they were procured with iron prepared at different
times. Platinum was always tried at the same time with the
gold, and when there was no gold dissolved I never obtained
any crystals.

I need hardly mention that both zinc and iron, when put
into the persalts of iron, first reduce the persalt to the pro-
tosalt, which fully accounts for the great consumption of iron
for the small quantity of copper obtained in these waste waters
of mines, and not, as was generally supposed, from the exist-
ence of free acid ; the copper is never all precipitated from
the water so long as persalts of iron exist in the solution.
The presence of persalts of iron also prevents the deposition of
the copper by a galvanic current ; the proportionate quantity
of persalts of iron necessary to resist completely the deposition
of copper was not ascertained.

In no one case did I find any double salt formed between
the iron and metal dissolved in it, but when the solution con-
taining them was evaporated the salts of the two metals cry-
stallized separately.

In all cases where the process is conducted cold the solu-
tion of the metal takes place at the bottom of the vessel and
progresses upwards; this is beautifully exhibited when a tall
glass is used with a solution of perchloride of iron, and a slip
of copper reaching to the bottom ; the solution first becomes
green at the lower part, and this advances slowly upwards till
it reaches the top, but before the change of colour reaches the
top the bottom has become colourless from the formation of
subchloride.

I may observe that the whole of these remarks are only the
prominent features noted down as they occurred, without any
idea of bringing them before the Society in this unfinished
state ; but having no hope of obtaining leisure for making
further investigations, I have given them as they are, thinking
that perhaps some one, having more time and ability, would
repeat the experiments and produce something more definite.

[371 ]

LV. Analyses of the Bath Waters and of the Bristol Hotvoell
Water. By William Herapath, Esq.
To the Editors of the Philosophical Magazine and Journal.
Gentlemen,
IJAVING been applied to by one of our public bodies for
A the two accompanying analyses, I have been reminded
by the circumstance that they have not appeared in any of
our periodical journals. I therefore forward them to you for
insertion, and

I remain, Gentlemen,
Mansion House, Old Park, Bristol, Your obedient Servant,

April 15, 1844. WlLLIAM HERAPATH.

Bath Waters*.

King's Bath, temperature of the source 114° Fahr., contents

of an imperial gallon of 70,000 grs.

grains.
Chloride of magnesium .... 5*976

Chloride of sodium 16*848

Sulphate of magnesia .... 7*456

Sulphate of soda 10*672

Bicarbonate of lime 8*152

Bicarbonate of iron *240

Bicarbonate of magnesia . . . trace

Sulphate of lime 90*480

Silica 1*760

141-584
Specimen taken July 1836.

Bristol Hofrwell Water.
Contents of an imperial gallon of 70,000 grs.
Carbonic acid gas. . 8*75 cubic inches.

Nitrogen gas . . . 6'56 ... grains.

Chloride of magnesium 2*180

Nitrate of magnesia £*909

Chloride of sodium 5*891

Sulphate of soda 3*017

Sulphate of magnesia . ....... 1*267

Carbonate of lime existing as bicarbonate . 1 7*700

magnesia ... ... . *660

iron «103

Bitumen *150

Sulphate of lime ......... 9*868

Silica «270

44*015
Specimen taken January 1843.

* Mr. R. Phillips's Analysis of the Bath Waters will be found in Phil.
Mag. vol. xxiv. p. 342. — Edit.

2 B2

[ 372 ]

LVI. Observations on Fermentation.
By John N. Furze, Esq.*

TN consequence of the practical inconveniences arising to
-*- brewers from want of control over the fermenting tuns,
and the changes in the worts dependent upon atmospheric
temperature, I was led to the following experimental obser-
vations.

The infusion of malt being made according to the usual
practice of brewing, the wort, or infusion, is boiled with the
hops, and being subsequently cooled, yeast to the amount of
about one pound by weight to the barrel of wort is added, and
the whole transferred to the fermenting tun, The general form
of a brewer's fermenting tun being that of a simple open vessel,
the worts lie exposed during their change of state without
covering and with free access of air. This, as is evident,
must expose the fermenting mass to the variations of atmo-
spheric temperature, which, in their turn, either check or
hasten the operation to such an extent, that the ultimate suc-
cess of the brewing is endangered, and not unfrequently con-
siderable loss is sustained. These disadvantages are occa-
sionally avoided in some of the larger breweries by the use
of fermenting tuns, which are so far inclosed as to leave but
sufficient space for the escape of the gaseous matters arising
from the surface of the worts when the fermentation is in full
vigour.

Having tried the above method without finding the desired
advantage to result from it, new measures of proceeding were
taken, as follows: — A circular tun was erected, whose total
content was 350 barrels, having a door in the side capable of
being made air-tight by lining its edges with coarse serge and
applying screw-pressure to the centre of it. To the upper
part of this tun, which was fitted with windows in the top and
sides to afford to the brewer an opportunity of viewing the
apparent changes in the worts, two India-rubber pipes were
attached, each of 1 inch internal diameter, to convey away
the gas generated during the process ; and, in order to pre-
vent external interference, the ends of the pipes were immersed
to the depth of about 3 inches in a vessel of water.

These arrangements must not be confounded with the at-
tempts of some persons, both in this country and in France,
to condense vapours which were supposed to rise in great
abundance from fermenting liquids, and which are well known
to have disappointed the expectations of the projectors. On
two occasions, when the plan of condensation was tried by

* Communicated by the Chemical Society ; having been read November
7, 1843.

Mr. J. N. Furze on Fermentation. 313

me, there was not any product, after passing the gaseous
matter through a worm three quarters of an inch diameter
and 35 feet in length, surrounded with water at a temperature
of 54-° for a period of 36 hours on each occasion.

Having arranged the improved tun as before described, the
gas arising from six fermentations was allowed to escape
through the water in the external vessel. After the gas had
thus been washed it had lost much of the pungency of smell
so characteristic of the usual mode of escape, and in a few
days the water had so far changed, that it had a strong foetid
odour, similar to that of waste starch liquors, and certainly
not that of the aroma of the hop. This, from the great dif-
ference between the water in question and that of the same
bulk which had not been so treated, must have resulted from
the absorption of a something passing off in mechanical sus-
pension with the gas. In order to ascertain the contents of the
water after being charged with the gas and vapour, some of
it was distilled, immediately after the transmission of the gas,
and the result was, that from 36 gallons of the water so em-
ployed, 9 pints of alcohol were obtained of specific gravity
0*850. Jt appeared, on further prosecuting the matter, that
more could have been obtained had a larger quantity of water
been used, and that the action of the water on the gas de-
pended for its efficacy, in a great degree, upon the apparatus
itself. In endeavouring to realize more extended results a
tub was made, which contained an arrangement of three tin
plates perforated with holes, set one inch apart from each
other, through which the gas passed in small bubbles, by
which means the washing of the gas was rendered more ef-
fectual. In this manner 3 per cent, of rough spirit was fre-
quently obtained, of specific gravity 0*850, by distillation from
the gas produced by one fermentation. All these distilled
products were impregnated with ammonia to a considerable
amount, which would necessarily affect these results, as is
shown by the following experiments.

45 gallons of water having received a charge of gas from
the fermentation of 350 barrels of porter wort had a specific
gravity 0*9988, and the attenuation of the worts during the
period was about 12 lbs. per barrel, as indicated by the sac-
charometer of Dring and Fage. Of this quantity 36 gallons
were reduced to one-sixth part by distillation, of which 16 oz.
by measure were again carefully rectified and reduced to 4 oz.,
which had a specific gravity 0*965, being equal to 33 percent,
of alcohol at 0*825. It therefore follows that the 45 gallons
would have yielded 15 imperial pints at 0*965, which would
equal 5 pints at 0*825, or about 1*4 per cent, of alcohol by
volume.

374 Mr. J. N. Furze on Fermentation.

5 oz. of the original 45 gallons were distilled with baryta
in excess, to combine with any acids that might be present,
and the product was redistilled with hydrochloric acid ; chlo-
ride of platinum and sodium was then added, and the whole
carefully evaporated to dryness ; the soluble parts having been
removed by alcohol left 1 *9 gr. of ammonio-chloride of plati-
num, which indicates by calculation 0'146 grain of ammonia.
It follows, therefore, that 4-672 grains of ammonia were con-
tained in the original bulk per gallon, or 21 0*24 grs. on the
whole volume.

The residue, after the distillation with barytes, was exa-
mined for acetic and formic acids, but without success.

Respecting the volume of carbonic acid eliminated during
the process of fermentation, I have not yet had the opportu-
nity of using an apparatus capable of measuring the amount
set free from so large a quantity of wort as 180 barrels. On
a small brewing of ale the quantity of gas measured by a very
large metre was 7900 cubic feet. The meter having been
charged with great care, the relative quantities were as fol-
lows:— 43£ barrels of ale wort attenuated 16'5lbs. per barrel,
and gave off 7900 cubic feet of carbonic acid, or about 1 1
cubic feet of gas for every pound of attenuation. Again, 91
barrels of ale wort attenuated 1 5 lbs. per barrel, and gave off
11,700 cubic feet of carbonic acid, or about 11*66 cubic feet
of gas for every pound of attenuation.

It being manifestly inconvenient to distil so weak a spirit
on a large scale, from the necessity of apparatus and arrange-
ments totally different from the usual machinery of a brewery,
the means of preventing the saturation of the gas by the va-
pour of alcohol was the next object. This is accomplished in
a most simple manner. The tun being air-tight, the exit-
pipes for the carbonic acid were allowed to dip into a vessel
of water to the depth of three feet, and by the pressure of the
confined gas upon the surface of the fermenting worts the
power of holding the vapour of the alcohol in the carbonic
acid gas is checked, and a very large proportion of spirit thus
retained, which would otherwise have been lost. The effect
was tested as before by distillation, and although the retention
was not complete, a most extraordinary reduction was made,
amounting in some instances to 80 per cent, of the before-
stated produce. The depth of 3 feet is of course an ar-
bitrary number, but in practice a greater pressure is inconve-
nient from the difficulty of keeping large tuns air-tight by
common means. The difference of the quantity of vapour
dependent upon pressure will be confirmed by the following
experiments, in addition to the test of distillation.

175 barrels of porter wort were fermented in a close tun,

Geological Society. 375

the exit-pipes of which were immersed in water to the depth
of 3 inches. During the process, at three different periods,
100 cubic inches of the gas were passed through desiccating
tubes, 1 7 inches long and half an inch in diameter, containing
chloride of calcium, and on each occasion, for every 100 cu-
bic inches, calculated as dry carbonic acid at a temperature
of 52°, 0*425 grain increase of weight was obtained, due to
the absorption of watery vapour.

181 barrels of porter wort fermented in the same vessel;
the pipes being immersed 3 feet, gave the following result.
For every 100 cubic inches, calculated as dry carbonic acid
at a temperature of 52°, only 0*20 grain of vapour was ab-
sorbed. It would appear therefore that the vapour of water
given off during the process of fermentation bears directly on
the proportion of alcohol carried away with the carbonic acid
gas. If the simplicity of the arrangement is a ground for its
recommendation, it must be evident that the foregoing appa-
ratus would claim the attention of those conversant with the
present system, as furnishing to the brewer a better control
over his fermenting tuns, and the production of a stronger
beverage from his worts.

I have much pleasure in acknowledging the material as-
sistance afforded me by my friend Mr. Robert Warington in
these investigations.

LVII. Proceedings of Learned Societies.

GEOLOGICAL SOCIETY.
[Continued from p. 313.]
May 10. A PAPER was read "On some new Ganoid Fishes." By
1843. xTl Sir Philip Grey Egerton, M.P., F.G.S.*

The specific characters of the fishes described are as follows : —

1. Semionotus Pentlandi, Egerton. — Body deep; pedicle of the tail
thicker proportionally than in Semionotus latus. Anal fin long, with
5 or 6 rays, articulated, subdivided, and decreasing in length from
the first. Bases distant ; 3 or 4 fulcral rays on the margin. Caudal
fin large ; upper lobe invested with scales for some distance. Mar-
gins fringed by elongated imbricated scales. Rays : 20, articulated,
subdivided. Bases at greater intervals near the centre. Scales
rhomboidal, smooth, with entire margins. Stratum, Lias.

Found by Mr. Pentland in a black bituminous schist at Giffoni,
near Castell-a-Mare. In the cabinets of the Earl of Enniskillen and
Sir Philip Egerton.

Of the six species of Semionotus described by Professor Agassiz,
one is from the quader-sandstein, the other five from the lias of
Lufeld, Boll, Lyme Regis, and Schoven in Sweden. From a com-
parison of Mr. Pentland's specimens of this and the two following

* This abstract is now inserted, having been omitted in its proper place.

376 Geological Society.

species with all those described, Sir Philip Egerton considers they
approximate more nearly the species of the lias than those of the
greensand, and infers from this zoological evidence that the Giffoni
beds belong to the former.

2. Semionotus pustulifer, Egerton. — Fish large; operculum arenated;
humerus and scapula pustulated ; scales thick and lustrous ; surfaces
slightly uneven ; upper and lower margins deeply undulate. Stratum,
Lias ; found with last. Cab. Egerton.

3. Semionotus minutus, Egerton. — Fish small; body slender; cau-
dal pedicle thick ; scales extended over the upper lobe of the tail.
Stratum, Lias ; found with last. Cab. Egerton.

4. Lepidotuspectinatus, Egerton. — -Fish oblong, subfusiform; length
9 inches ; depth 2§ ; head small ; fins small ; scales marked with
delicate radiating striae ; posterior margin finely pectinate ; upper
edge convex, lower one concave ; dorsal, anal and caudal scales
rhomboidal, with entire margins. Stratum, Lias. Locality, Whitby.
Cab. Enniskillen.

5. Pholidophorus Hartmanni, Egerton. — Size of Pholidophorus
latiusculus. Head rounded ; orbit large ; upper angle of operculum
striated ; preoperculum marked with few moniliform inequalities ;
humerus plicated ; scales small, serrated on the posterior margin ;
its serrations decrease in number and increase in size on the pos-
terior parts of the body. Stratum, Lias. Locality, Ohmden, in Wur-
temburg. Cab. Enniskillen, Egerton.

6. Pholidophorus crenulatus, Egerton. — Rather larger than Pho-
lidophorus latiusculus. Head rather pointed; humerus obliquely
plaited ; pectoral fins large, with 22 rays ; caudal fins strong ; the
upper lobe bordered full two-thirds of its length with fulcral scales ;
rays 28 — 30 ; scales ribbed vertically on their bases, furrowed hori-
zontally on their exposed surface, and crenulated on the posterior mar-
gin ; the ventral scales deeply incised. Stratum, Lias. Locality, Lyme
Regis. Cab. Egerton.

June 21. — The following papers were read : —

1. " Supplement to a Memoir on the Fossil species of Chimara."
By Sir P. Grey Egerton, M.P., F.G.S.

Since the author's former memoir was communicated to the So-
ciety*, he has seen in the collection of Mr. Dixon a new and striking
addition to the genus Ischyodus. The specimen is from the chalk
of Southeram, and presents two dental plates only slightly dislocated
from their natural juxtaposition. At first sight these would appear
to be the dental armature of the lower jaw, corresponding nearly in
size to the lower mandibles of Ischyodus Mantelli. A closer exami-
nation has satisfied Sir Philip Egerton that they are in reality the
intermaxillary plates of the upper jaw of a most gigantic chimeeroid.
They exceed in size the corresponding teeth of Ischyodus Toumshendi,
the largest species hitherto found, by one third. As compared with
the intermaxillaries of that species they are broader, more compressed
and less robust in antero-posterior diameter, and less hooked at the

* An abstract of Sir P. Egerton's former memoir has appeared in the
present volume, p. 51. — Edit.

Geological Society. 377

extremity. The form of the cutting edge is not truncate, as in the
recent Chimcera, but prolonged to an acute angle, and bent down-
wards like the upper mandible of a bird of prey. The symphysis is
smooth and slightly hollowed. The thin polished investing lamina
of compact dentine is seen adhering to the surface of the tooth. On
the interior surface this is marked with broad transverse irregulari-
ties similar to, although less distinct than, those seen in the recent
Chim<era. A fragment in Mr. Dixon's collection gives evidence of
having belonged to an individual of much larger size than that which
furnished the specimens here described. Sir Philip Egerton proposes
to name this species Ischyodus Gigas.

2. " On the occurrence of the remains of Insects in the Upper Lias
of the county of Gloucester." By James Buckman, F.G.S.

The remains described in this paper were discovered by Mr. Buck-
man in a thin seam of argillaceous limestone in the upper lias beds
at Dumbleton, a village twelve miles from Cheltenham, to which his
attention had been directed by Mr. Brodie, who had suspected the
existence of insect remains in the stratum. The section of Dum-
bleton Hill, which is a liassic outlier, presents the following beds.

ft. in.

1 . Sandy debris from the oolite, about 10 0

2. Upper lias shale : this is traversed at twelve feet from

its base by the thin bed of fissile limestone five inches

in thickness 60 0

3. Lias marlstone, about 20 0

90~0
The thin seam of limestone included in No. 2 is remarkable for
containing many organic remains not found in any other part of the
lias, and most of them new, comprising land as well as marine ani-
mals and traces of plants. Among them are two undetermined
species of fish with numerous fish-scales and coprolites, two species
of Crustacea, the one allied to Astacus (Fabr.), the other to Hippo-
lyte (Leach). A species of Loligo, a new Belemnite, a new Ammo-
nite (which Mr. Buckman has named A. Murleyi), A. corrugatus
and ovatus, a small univalve in great abundance, and Inoceramus du-
bius. The remains of insects comprise one species of Libellula,
which, from the reticulations of the fine wings, seems to belong to
the genus Mschna, Fabr., and has been named by Mr. Buckman
A3. Brodiei, in honour of Mr. Brodie ; two species of Coleoptera of
undetermined genera, and a wing supposed to belong to Tipula.
None of these are of the same species with the insects found by Mr.
Brodie in the lower has*.

From the presence of a similar band of stone with that containing
the above mentioned fossils at Churchdown and Robin Hood Hill,
liassic outliers presenting the same section as that of Dumbleton
Hill, Mr. Buckman supposes that this thin seam is of constant oc-
currence in the upper lias of the neighbourhood. He concludes that
the period, which the state of things which produced it continued, was
not of long duration, and that its deposition was of a quiescent kind.
* See Phil. Mag. S. 3. vol. xxiii. p. 529.— Edit.

378 Zoological Society.

3. " Outline of Geological Structure of North Wales." By the
Rev. A. Sedgwick, F.G.S. The official abstract of this paper has
already been inserted in the present volume, p. 246.

ZOOLOGICAL SOCIETY.

November 28, 1843. — Prof. Owen read the second and concluding
part of his memoir on the Dinornis*.

The arrival of the second box of specimens of the bones collected
by the Rev. W. Williams in Poverty Bay, New Zealand, which had
been placed by Dr. Buckland in Mr. Owen's hands, had enabled him
to confirm his former account of the generic characters and ordinal
affinities of the apparently extinct Dinornis, and also to distinguish
remains of five species of that genus.

The bones of the foot, and especially the tarso-metatarsal bone,
established three distinct species, the largest of which the author
proposed to call Dinornis giganteus ; the next in point of size he
termed Din. struthioides , and the third Din. didiformis. The com-
mon generic characters of the tarso-metatarsi of these species were
first pointed out, and then their specific differences of proportion and
figure. The maturity of the different- sized bones indicating the
above species was demonstrated by reference to the long retention
of immature characters in the same bone of existing Strut hionidee,
and by the fact of a tarso-metatarsal bone of a half-grown Dinornis
giganteus manifesting the same incomplete coalescence of its primi-
tively distinct elements ; showing that the Dinornis, like the Ostrich,
had a tardy ossification of the skeleton, as compared with birds of
flight. The tibiae were next described ; one of these, belonging to a
mature bird, established a species smaller than the Din. didiformis,
and which, from its similarity of stature to the great Bustard (Otis
tarda), Prof. Owen proposed to call Dinornis otidiformis. The
largest tibia, belonging to the Din. giganteus, presented the extra-
ordinary dimensions of two feet eleven inches. The shaft of a
smaller tibia, about two feet long when entire, was referred to the
Din. struthioides, and there were four entire tibiae of the Din. didi-
formis. In the series of femora, after the description of the generic
characters of the bone, the specimens were pointed out which be-
longed to the Dinornithes giganteus, struthioides, didiformis, and oti-
diformis, and two other entire femora were described and their di-
stinctive characters shown, which indicated, unequivocally in the
author's opinion, a fifth species of Dinornis, of the size of the Emeu,
and which was, therefore, named Din. dromceoides.

Three pelves, more or less perfect, and portions of two others,
were described, and were referred to the Din. giganteus, dromceoides,
and didiformis. Three cervical and two dorsal vertebrae also indi-
cated three distinct species of Dinornis, and all of them presented
the common character of unusual strength of the spinous and trans-
verse processes. Comparative dimensions of most of the bones ex-
hibited were given. No part of the skull, sternum, ribs or wing-

* See Proceedings of the Zoological Society, January 1843 [also Phil.
Mag. S. 3. vol. xxii. p. 558].

Professor Owen on the Dinornis. 379

bones had been transmitted, but Prof. Owen proceeded to point out
the physiological grounds for concluding that the development of
the anterior extremities must have presented in the Dinornis an in-
termediate condition between that in the Emeu and that in the
Apteryx.

The author then gave his calculations, from the analogies of
existing Struthious birds, of the height of the different species of
Dinornis. The largest, Din. giganteus, according to the proportions
of the Ostrich, must have stood ten feet five inches, but according
to those of the Cassowary, nine feet five inches ; its average stature
might be taken at ten feet. A diagram of the great extinct bird,
restored according to these proportions, was exhibited.

The Dinornis struthioides was seven feet high, which is the average
stature of the Struthio Camelus.

The length of the tibia and metatarsus of the Din. dromceoides not
yet being known, the height of five feet was assigned to it as a pro-
bable one ; its femur corresponds in size with that of the Emeu,
whose average measurement in captivity is between five and six feet.

The height of the Din. didiformis was four feet; exceeding, there-
fore, the extinct Dodo (Didus ineptus), but evidently resembling it
in its stouter proportions and shorter metatarsus, as compared with
the other species of Dinornis.

Prof. Owen next proceeded to consider the evidences of tridactyle
birds afforded by the impressions in the New Red Sandstone of Con-
necticut, called ' Ornithichnites,' and having pointed out the propor-
tions of the tarso-metatarsal bone in existing Struthious birds to
their foot-prints, indicated thereby the size of the same bone in dif-
ferent Ornithichnites, and reciprocally the sizes of the foot-prints of
the different Dinornithes, from those of their tarso-metatarsal bones.

The two phalanges of the Dinornis, which were described and
compared in this section of the memoir, afforded pretty clear indi-
cations of the form and proportions of the toes in the two species
{giganteus and didiformis) to which they were referred. These data
showed that the trifid foot-print of the Dinornis giganteus must have
exceeded in size the Ornithichnites giganteus and O. ingens of Prof.
Hitchcock, and that the Din. didiformis must have left impressions
as large as those called Ornithichnites tuberosus. The author warned
his hearers against inferring identity of species or even genus between
the extinct Struthionidce of the alluvium of New Zealand and those
of the trias of North America, on account of correspondence of size
and number of toes, which the modern genera Casuarius, Rhea, &c.
proved to be insufficient grounds. He concluded by a comparative
review of recent and extinct Struthionidce, remarking on their peculiar
geographical distribution, on the conditions which favoured the for-
mer existence of so rich a development of the family in New Zealand,
and on the probable causes of their extermination. Evidence of the
recent character of the bones described was afforded by the great
proportion of animal matter which they retained, and the details of
the analysis of the earthy salts were promised for a future Meeting.

[ 380 ]

ROYAL IRISH ACADEMY.

May 8, 1843. — Sir Wm. R. Hamilton, LL.D., President, in the
Chair.

Professor MacCullagh read the following communication : — On
the Laws of Metallic Reflexion, and on the Mode of making Expe-
riments upon Elliptic Polarization.

Several years ago, as the Academy are aware, I made an attempt
to investigate the laws according to which light is reflected at the
surfaces of metals, and I then proposed certain formulae which repre-
sented, with sufficient accuracy, all the facts and experiments which
I was able to collect upon the subject (see the Proceedings of the
Academy, vol. i. p. 2, October 1836 ; Transactions, vol. xviii. p. 71,
note). But in order to test these formulae satisfactorily, it was ne-
cessary to obtain measurements far more exact than any that had
previously been made ; and for this end I devised an instrument,
which was constructed for me by Mr. Grubb, and of which a brief
description has been given in the Proceedings, vol. i. p. 159. I regret
to say, however, that nothing of much consequence has yet been done
with the instrument. Some preliminary trials of its performance
were indeed made in the summer of 1837, and the results of one of
these shall presently be given ; but an accidental strain which it suf-
fered, while I was preparing to undertake a series of experiments,
caused me to discontinue the observations at the time ; and being
then obliged to superintend the printing of my essay on the Laws of
Crystalline Reflexion and Refraction (Transactions R. I. A., vol.
xviii. p. 31), my attention was drawn afresh to this latter subject,
respecting which some new questions suggested themselves, which I
thought it right to discuss in notes appended to the essay. I was
not afterwards at leisure to take up the experimental inquiry, until
the beginning of the year 1839, when I began to think of putting
the instrument in order for that purpose. The strain which it had
suffered rendered some slight alterations necessary; and I now re-
solved to make additions to it also, with the view of operating upon
the fixed lines of the spectrum, as a few trials had convinced me that
measures sufficiently precise could not be obtained without employ-
ing light of definite refrangibility. I wished, moreover, to take the
opportunity which the nature of the proposed experiments presented,
of verifying the theory of Fresnel's rhomb, or rather of verifying, by
means of the rhomb, the formulae which Fresnel has given for com-
puting the effects of total reflexion, when it takes place at the
common surface of two ordinary media. I wrote therefore to Mu-
nich for several articles which I wanted ; among others, for a set of
rhombs cut at different angles, out of different kinds of glass. But
while I was waiting for these some months elapsed, and in the mean-
time I got sight of a new theory, which, from its connexion with my
former researches, possessed more immediate interest, and the pur-
suit of which, in conjunction with other studies and various engage-
ments, caused me again to suspend the inquiry respecting the laws
of metallic reflexion. I allude to the Dynamical Theory of Crystal-
line Reflexion and Refraction, communicated to the Academy in

Royal Irish Academy. 381

December 1839 (Proceedings, vol. i. p. 374*). This was followed
soon after by a general Theory of Total Reflexion (Proceedings, vol.
ii. p. 96f)» founded on the same principles. The latter theory, form-
ing a new department of physical optics, and involving the solution
of questions not previously attempted, was analytically complete when
it was communicated to the Academy in May 1841 ; but its geome-
trical development has since required my attention from time to time,
and has not yet been brought to that degree of simplicity of which
it appears to be susceptible (see Proceedings, vol. ii. p. 174). Indeed
I have found that, in this instance, the geometrical laws of the phe-
nomena are by no means obvious interpretations of the equations re-
sulting from the analytical solution of the problem ; and in endea-
vouring to verify such supposed laws I have often been led to alge-
braical calculations of so complicated a nature that it has been im-
practicable to bring them to any conclusion, and I have been obliged,
from mere weariness, to abandon them altogether. On returning,
however, to the investigation, after perhaps a long interval of time,
I have usually perceived some mode of eluding the calculations, or
of directly deducing the geometrical law ; and when the theory comes
to be published in its final form, no trace of these difficulties will
probably appear.

From the causes above mentioned, combined with frequent absence
from Dublin, the researches which I had entered upon, respecting
the action of metals upon light, have been hitherto interrupted ; and
as it may still be some time before they are resumed, I venture, in
the meanwhile, to submit to the Academy the results already spoken
of, which were obtained on the first trial of the instrument, and which
afford the best data that can yet be had for comparison with theory.

The results, it must be confessed, are those of very rough experi-
ments, made one evening (about the month of July 1837) in com-
pany with Mr. Grubb, before I had received the instrument from his
hands, and merely with the view of showing him, when it was finish-
ed, the kind of phenomena that I proposed to observe with it, and
the mode of observing them. But the instrument was so far supe-
rior (in workmanship at least) to any apparatus previously employed
for this sort of experiments, that it was impossible, without great
negligence in using it, not to obtain measures of considerable accu-
racy. I did not, however, at the time, set much value on these mea-
sures, because I expected shortly to possess a series of observations
made with every possible precaution ; but having chanced to preserve
the paper on which they were noted down, I was tempted, a few days
ago, to try how far they agreed with my formulae ; and the agree-
ment turns out to be so close, that I think myself justified in publish-
ing them. Besides, it will be curious hereafter to compare them
with more careful measurements.

Before we proceed, however, to the details of the experiments, it
may be well to give the formulae in a state fitted for immediate ap-
plication. The light incident on the metal being polarized in a cer-
tain plane, let a denote the azimuth of this plane, or the angle which
* Phil. Mag. S. 3. vol. xvi. p. 229; vol. xxi. p. 228.— Edit.
f lb. vol. xxiii. p. 137. — Edit.

382 Royal Irish Academy.

it makes with the plane of incidence ; and as the reflected light will
he elliptically polarized, or, in other words, will perform its vibra-
tions in ellipses all similar and equal to each other, as well as simi-
larly placed, put 6 for the angle which either axis of any one of these
ellipses makes with the plane of incidence, and let ft be another
angle, such that its tangent may represent the ratio of one axis of
the ellipse to the other. Then when the optical constants M and %
(of which I suppose the first to be a number greater than unity, and
the second an angle less than 90°) are known for the particular
metal, the angles 0 and ft may be computed for any value of a, at
any given angle of incidence, by the following formula? : —

tan20 = /(,'-y)8fa2g , sin2/3 = , 2gsi"2" . (A.)
2/+ (v' + v)cos2a H v' + y + 2/cos2a v '

in which /and g are constant quantities given by the expressions

/=(M-^-)cos%, 9=(M + ^ymX,. . (B.)

and v, v' are quantities depending on the angle of incidence i, in the
following way. Let i' be an angle such that

sin i M /n .
(W

and put
then will

cos^'

cos%

v = J_-^, *m£±j£ (e.)

The angles 6 and ft are given by immediate observation with the in-
strument ; and from their values at any incidence, and for any azi-
muth a of the plane of primitive polarization, we can find the con-
stants M and %, which we may afterwards use to calculate the values
of 0 and ft for all other incidences and azimuths, in order to compare
them with the observed values. It is indifferent, in the formulae,
whether 0 be referred to the major or the minor axis of the elliptic
vibration, as also whether tan ft be the ratio of the minor to the
major axis, or the reciprocal of that ratio ; but in what follows we
shall suppose 6 to be the inclination of the plane of incidence to that
axis, which, when a is 45° or less, is always the major axis ; and ft
shall be supposed less than 45°, in order that its tangent may repre-
sent the ratio of the minor axis to the major.

When the azimuth a is equal to 45°, the formulae (A.) become

tan20 = ^, sin 2/3 = -*£-; .... (F.)
2/ v 4- y

from which we may deduce the remarkable relation

tan 2/3 __ g_ ,G .

cos 2 6 f'

showing that, in the case supposed, the ratio of tan 2 ft to cos 2 d is

independent of the angle of incidence. In the experiments which I

made with Mr. Grubb this azimuth was always 45° ; and the follow-

Royal Irish Academy.

383

ing Table contains the results of observation compared with those
obtained by calculation from formulae (F.). The experiments were
made upon a small disc of speculum metal ; and in the calculations
I have taken M = 2- 94, x — 64° 25'-

Value of 9.

Value of /3.

Angle of
incidence.

Observed.

Calculated.

Observed.

Calculated,
o /

o /

o '

o /

65

27 55

27 53

28 0

28 0

70

15 41

15 44

33 7

33 1

75

- 8 45

— 9 16

34 10

34 6

80

-30 15

—29 25

27 0

26 53

84

-37 22

-37 25

16 47

17 17

The light used in these observations was that of a candle placed
at a short distance, and was admitted through small apertures at the
ends of the tubes (see the description of the instrument in the Pro-
ceedings, vol. i. p. 159). The Nicol's prism in the first tube having
been secured in a position in which its principal plane was inclined
45° to the plane of incidence, and the two arms having been set at
the proper angle with the surface of the metal, the Fresnel's rhomb
and the Nicol's prism in the second tube were moved simultaneously,
until the image of the candle became as faint as possible. Had light
perfectly homogeneous been employed, the image could have been
made to vanish altogether ; but instead of vanishing, it became highly
coloured, and our rule in observing was to make the blue at one side
of it, and the red at the other, equally vivid, so as to get results which
should belong, as nearly as possible, to the mean ray of the spec-
trum. When this was done, the angles 0 and /3 (subject however
to certain corrections which will be hereafter explained) were re-
spectively read off from the divided circles belonging to the rhomb
and the prism. The observations were made at large incidences,
because it is within the last thirty degrees of incidence that the phe-
nomena go through their most rapid changes.

If we now cast our eyes on the above table, making due allowance
for the uncertainty arising from the dispersion of the metal, we shall
be struck with the agreement between the calculated and observed
numbers. The differences are greatest in the last two observations,
which however were really the first ; for the observations were made
in the inverse order of the incidences, and their accuracy may have
improved as they went on. However that may be, the differences
are quite within the limits of the errors of observation ; and they are
actually less than those which Fresnel found to exist between calcu-
lation and experiment in the much simpler case of reflexion at the
surface of a transparent ordinary medium, when he proceeded to
verify the formula which he had discovered for computing the effect
of such reflexion (see the Table which he has given in the Annates
de Chimie, torn. xvii. p. 314).

It may seem extraordinary that these experiments should have

384i Royal Irish Academy.

been in my possession for nearly six years, before I became aware of
their close agreement with my formulae ; but the fact is, that I did
not regard them with much interest, because, from the circumstances
in which they were made, I did not expect more than a general ac-
cordance with theory. And even now I am in no haste to infer the
absolute exactitude of the formulae, though they are found to repre-
sent the phaenomena so well. It was far more allowable to infer
that the formula of Fresnel was exact in the case just mentioned,
though it appeared to represent the phaenomena less perfectly. For,
to say nothing of the small number of our experiments, the present
is a much more complicated case, and the phenomena depend on
two constants instead of one, so that the formulae might be slightty
altered, and yet perhaps continue to agree very well with rough ex-
periments. Where there is only one constant this is not so probable.
Again, there is one of the quantities in the preceding formulae which
may be greatly altered without producing more than a slight effect
on the values of d and /3. This quantity is the ratio of sini to sini',
which, according to the value in formula (C), is a number so large
as to make the angle V always small, so that its cosine never differs
much from unity ; and therefore if the above ratio were taken equal
to any other large number, the value of ju. in formula (D.) would re-
main nearly the same, and consequently the values of d and |3 would
be but slightly changed.

It is with regard to the value of jtx, as a function of the incidence
that I entertain the greatest doubts, and if any defect shall be found
in the formulae I think it will be here. The relations (C.) and (D.),
from which (* may be deduced in terms of i, were not indeed adopted
without strong reasons ; but I am not entirely satisfied with them,
because, when we reverse the problem, and seek to determine the
constants M and % from the observed values of 6 and j3 at a given
incidence, the results are rather complicated and involved, though
the approximate determination is easy enough. As the formulae are
in a great measure built upon conjecture, we must not be disposed
to receive them without the strongest experimental proofs; and it
will certainly require experiments of no ordinary accuracy to decide
some of the questions which may be raised respecting them.

When plane -polarized light is incident on a metal, if its vibrations
be resolved in directions parallel and perpendicular to the plane of
incidence, the effect of the reflexion is to change unequally the phases
of the resolved vibrations ; and it may be useful to have the formulas
which express the difference of phase after reflexion, and the ratio
of the amplitudes of vibration. Put <{> for the difference of phase ;
and supposing, for simplicity, the incident light to be polarized in
an azimuth of 45°, let cr be angle less than 45°, such that tan <r may
represent the ratio of the reflected amplitudes respectively perpen-
dicular and parallel to the plane of incidence ; then we shall have

tand> = -r— i— , cos 2 cr = , J ; .... (H.)

v' — v v' + v

from which we may infer that

Royal Irish Academy. 385

sin <j> tan 2 cr = SL, (I.)

or that the product on the left side of the last equation is indepen-
dent of the angle of incidence. It is to be observed that the relations
(G.) and (I.) are independent of the value of [/., and may hold good
though that value should require to be changed.

All the preceding formulas are merely mathematical consequences
of those which I published long ago in the Transactions of the Aca-
demy (vol. xviii. p. 71). The formulae which I had previously given
in the Proceedings (vol. i. p. 2) are slightly different, and, I think,
less likely to be exact, because they are less simple, and do not lead
to any of the remarkable relations which may be deduced from the
others.

Having had occasion, in the course of the few experiments which
I made with the instrument before mentioned, to study the nature
of Fresnel's rhomb, which constitutes an important part of it, I shall
here describe the method which must be followed in order to obtain
true results, when the rhomb is employed in observations on light
elliptically polarized. A ray in which the vibrations are supposed
to be elliptical is given, and what we want is to determine the ratio
of the axes of the elliptic vibration, and their directions with respect
to a fixed plane passing through the ray ; in other words, to deter-
mine the angles which we have denoted by /3 and 6 in the case of a
ray reflected from a metal. For this purpose the ray is admitted
perpendicularly to the surface at one end of the rhomb, and after
having suffered two total reflexions within, passes out perpendicu-
larly to the surface at the other end. Then causing the rhomb to
revolve about the ray, we shall find two positions of it in which the
emergent light will be plane-polarized, these positions being readily
indicated by a Nicol's prism interposed between the rhomb and the
eye ; for such a prism, by being turned round the ray, can make the
light totally disappear when it is plane-polarized, but not otherwise.
These two positions of the rhomb will be exactly 90° from each
other ; in one of them the principal plane of the rhomb (the plane of
reflexion within it) will be parallel to the major axis of the elliptic
vibration, and the angle which it makes with the plane of incidence
on the metal will be equal to d : while in the same position the angle
which the principal plane makes with the plane of polarization of the
emergent ray (as given by the Nicol's prism) will be equal to fi. In
the other position, the principal plane will be parallel to the minor
axis of the elliptic vibration, and the corresponding angles will be
equal to 90° — 0 and 90° — /3 respectively. This, however, proceeds
on the supposition that the rhomb is exact. When it is not so,
which is of course the proper supposition, and a very necessary one
in the experiments with which we are concerned, there will still be,
generally speaking, two positions of it in which the emergent ray
will be plane-polarized, or in which a disappearance of the light may
be produced by the Nicol's prism ; but these positions will no longer
be 90° from each other, nor will the principal plane, in either of
them, coincide with an axis of the elliptic vibration. If we now

Phil. Mag. S. 3. Vol. 24. No. 160. May 1844. 2 C

386 Royal Irish Academy.

measure the angles between the different planes as before, and denote
them by &, /3' in the first position, and by 90° — 0", 90° — /3" in
the second, we shall find that 0' and 0" are unequal, but we shall
have /3' equal to /3". The values of 0 and /3 will then be given by the
formulae

8 = 61±JH, cos 2/3= C°9,2^' . . . (K.)

2 r cos(0'-0") v J

The error of the rhomb may easily be found. Supposing the vi-
brations to be resolved in directions parallel and perpendicular to its
principal plane, the rhomb is intended to produce a difference of 90°
between the phases of the resolved vibrations, or to alter by that
amount the difference of phase which may already exist ; but the
effect really produced is usually different from 90°, and this differ-
ence, which I call s, is the error of the rhomb. The value of s is
given by the formula

sin(0'-0") n y.

tane = i — ^ . ' \ (L.)

tan 2/3 v J

and as the error of the rhomb is a constant quantity, we have thus
an equation of condition which must always subsist between the
angles 0' — 0" and /3. For any given rhomb the sine of the first of
these angles is proportional to the tangent of twice the second, and
therefore 0' — 0" constantly increases as /3 increases towards 45°, that
is, as the axes of the elliptic vibration approach to equality. When
j3 is equal to 45° — \ s, we have 0' — 0" ss 90° ; and for values of
/3 still nearer to 45°, the value of sin (0' — 0") becomes greater than
unity, that is to say, it becomes impossible, by means of the rhomb,
to reduce the light to the state of plane-polarization. This is a case
that may easily happen with an ordinary rhomb in making experi-
ments on the light reflected from metals ; because at a certain inci-
dence, and for a certain azimuth of the plane of primitive polariza-
tion, the reflected light will be circularly polarized.

The rhomb which I used in the experiments tabulated above, was
made by Mr. Dollond, and was perhaps as accurate as rhombs usu-
ally are ; it was cut at an angle of 54^°, as prescribed by Fresnel.
Its error was about 3°, and the value of 0' — 0", at the incidence of
75°, was about 7°. But in another rhomb, also procured from Mr.
Dollond, and cut at the same angle, the value of 0' — 0", under the
same circumstances, was about 20°, and the value of s was therefore
about 8°. The angle given by Fresnel was calculated for glass of
which the refractive index is 1*51 ; and the errors of the rhombs are
to be attributed to differences in the refractive powers of the glass.
I was not at all prepared to expect errors so large as these when I
began to work with the rhomb, and they perplexed me a good deal
at first, until I found the means of taking them into account, and of
making the rhomb itself serve to measure and to eliminate them.
The value of the rhomb as an instrument of research is much in-
creased by the circumstance that it can thus determine its own effect,
and that it is not at all necessary to adapt its angle exactly to the re-
fractive index of the glass. It may also be remarked, that this cir-

Royal Irish Academy. 387

cumstance affords a method of directly and accurately testing the
truth of the formulae which Fresnel has given for the case of total
reflexion at the separating surface of two ordinary media ; for we
have only to measure the angle of the rhomb and the refractive index
of the glass, and to compute, by Fresnel's formula, the alteration
which the rhomb ought to produce in the difference between the
phases of the resolved vibrations ; which alteration of phase we may
then compare with that deduced, by means of the formula? (K.) and
(L.), from direct experiment.

If, in each position of the rhomb, we measure the angle which the
plane of polarization of the emergent ray makes with the plane of
incidence on the metal, and call the two angles respectively y', y",
we shall have

7' = 0'_/3', y" = d" + ft', .... (M.)
and therefore

y' + y» = o' + 8" = 26, 2ft, = y"-y' + e'-6"; (N.)
from which it appears that if the rhomb were perfectly exact, that
is, if 0' and 0" were equal to each other, the angle 0 would be half
the sum of y' , y", and the angle ft half their difference. It would
then be sufficient to measure the angles y' and y", in order to get 6
and ft accurately. And if the rhomb were erroneous, the true value
of 6 would still be half the sum of y' , y" ; but the true value of ft
would not be discoverable without measuring the angles &, 6'1, by
the help of which it can be deduced from the second of formula; (N.),
combined with the second of formula? (K.). Nor can we discover
whether the rhomb is erroneous or not, without measuring the angles
6', 6" ; and therefore as these angles must be measured in any case,
the former method of determining d and ft is to be preferred.

In making experiments on elliptically polarized light, a plate of
mica or any other doubly refracting crystal, placed perpendicular to
the ray, may be used instead of Fresnel's rhomb. If the thickness
of the crystalline plate be such that the interval between the two
rays which emerge from it is equal to the fourth part of the length
of a wave, for light of a given refrangibility, the plate will, for such
light, perform all the functions of the rhomb ; the principal plane of
the rhomb being represented by the plane of polarization of one of
the emergent rays. But unless the light be perfectly homogeneous,
this method is liable to great inaccuracy in practice, since the effect
of the plate in producing or altering the difference of phase between
the two rays which interfere on their emergence from it, is inversely
proportional to the length of a wave, and will therefore be extremely
different for light of different colours, and will change very per-
ceptibly even within the limits of the same colour. It is true, the
effect of the rhomb also varies with the colour of the light : but this
variation is trifling compared with that which exists in the other
case. It was for this reason that I employed the rhomb in my ex-
periments, instead of a crystalline plate. The apparatus, however,
is much simplified by using such a plate ; and if any one chooses to
do so, and to work with homogeneous light, he must take care to
follow, in every respect, the directions which I have given for con-

2 C2

388 Royal Irish Academy.

ducting experiments with the rhomh. The two cases are precisely-
similar ; and if it he necessary not to neglect the errors of the rhomb,
it is certainly not less necessary to take into account those which
may arise from a want of accuracy in the thickness of the plate, con-
sidering how difficult it is to make the thickness correspond exactly
to the particular ray which we wish to observe.

I have been induced to enter into these particulars, respecting the
mode of making experiments on elliptic polarization, because the
subject is one which has not hitherto been studied ; nor does it seem
to have occurred to any one that any precaution was requisite beyond
that of getting the rhomb cut as nearly as possible at the proper
angle, or the crystalline plate made as nearly as possible of the proper
thickness. This, indeed, was quite sufficient for ordinary purposes.
For example, light polarized in a plane inclined 45° to the principal
plane of the rhomb or of the plate, would, as far as the eye could
judge, be circularly polarized after passing through either of them.
Notwithstanding a certain error in the angle of the one, or in the
thickness of the other, such light would, when analysed by a rhom-
boid of Iceland-spar, give two images always sensibly equal in in-
tensity. But an error which could not be at all detected in this way,
might produce a very great effect in such experiments as those upon
the metals, and, for the purpose of comparison with theory, might
render them entirely useless, if in the first method of observing we
relied upon one set of observations, taking (suppose) the values of 6'
and ft' for the true values of 6 and ft ; or if, in the second method,
we contented ourselves with merely measuring the angles y' and y".
The necessity of attending to the foregoing rules and remarks will
appear from an examination of the experiments of M. de Senarmont,
published in the Annates de Chimie, torn, lxxiii. pp. 351-358. In
these very elaborate experiments, which were made upon light re-
flected at various incidences from steel and speculum metal, the
author followed a plan similar to that which I have adopted, and
which, in a general way, I had previously sketched in the Proceed-
ings of the Academy (vol. i. p. 159). There was this difference,
however, that he used a plate of mica instead of Fresnel's rhomb.
Now as he worked with common white light, the use of the mica
plate must have rendered two kinds of errors unavoidable. In the
first place, it would be impossible always to take the observations for
the same ray of the spectrum ; and next, as a consequence of this,
the thickness of the plate would be generally inexact for the parti-
cular ray to which the observations happened to correspond. If the
thickness of the plate were exact for a certain ray, it would be very
sensibly inexact even for the neighbouring parts of the spectrum ;
and as the part of the spectrum to which the observations belonged
was continually changing, the results obtained for different incidences
and azimuths would not be comparable with each other, even though,
in each separate case, the error of the plate were allowed for and
eliminated. The values of 6, however, as determined by M. de Se-
narmont, would be correct, so far as this error is concerned ; those
of ft alone would be erroneous. For the values of d were determined

Royal Irish Academy. 389

in two ways : by measuring the angles 0', 0", and taking their sum
for 2 0 ; also by measuring the angles y', y", and taking their sum
for the same quantity. Now each of these methods gives a true
value of 0, because by the preceding formulae we have 2 0 = 0' + 0 '
=y'+ y" ; and this accounts for the agreement, shown by the tables
of M. de Senarmont, between the values* of 2 0 obtained by these
different methods. But the values of /3 were deduced from the angles
y', y", by simply making their difference equal to 2 j3 ; and we see
by the second of formulae (N.) that, when the plate is not of the
proper thickness, this value of 2 /3 is erroneous by the whole amount
of the angle 0'— 0", the difference between fi' and /3 being supposed
so small that it may be neglected. As M. de Senarmont proceeded
on the common assumption that when the thickness of the plate has
been adjusted to that part of the spectrum to which the observations
are intended to refer, it may afterwards, through the whole series of
experiments, be regarded as exact, he necessarily conceived 0' and 0"
to be the same angle ; and it was on the principle of taking an ave-
rage between two measures of the same quantity, that he made the
supposition 2 0 = 0'+ 0", which happened to be correct. When
therefore he found 0' and 0" to be different, he of course looked upon
the difference as merely an error of observation, which it would be
superfluous to tabulate. Not having the values of this difference,
therefore, we have not the means of immediately correcting the values
of 2 j3. But as observations were made for several azimuths at each
angle of incidence, we may use the values of 0 to determine those of
/3 ; for when at any incidence (except that of maximum polarization,
where 0=0 for all azimuths) the values of 0 are known for two given
values of a, we can deduce the corresponding values of j3, without
any other theory than that of the composition of vibrations. The
values of /3 so deduced must indeed be expected to be very inaccu-
rate, partly because of errors in the observed values of 0, partly be-
cause the observations in different azimuths do not answer to the
same ray of the spectrum ; but they will be accurate enough to show
the great amount of the error committed by neglecting the difference
0' — 0'. For example, putting 0O and /30 for the values of 0 and /3
when a = 45°, M. de Senarmont gives, at the incidence of 60°
upon steel, 2 0O = 64° 15' (taking the mean of his two determina-
tions), and for the azimuths 55°, 30°, 25°, he gives 2 0 equal to
88° 5', 37° 2', and 29° 36' respectively. Combining these values of
20 in succession with that of 20o, we get for 2/30 the series of values
32° 38', 33° 28', 34° 30' ; the differences between which are to be
attributed to the causes above stated. The mean value of 2 /30 thus
found is 33° 32' ; while its value, as given by M. de Senarmont, is
only 28° 41'. The difference 4° 51' is the value of 0' — 0", which,

* Or rather the values of 180°+ 2 & ; because the angle a, the double of
which appears in the tables of M. de Senarmont, is equal to 90°+ 0. The
angles which he calls yi and y2 are equal to 90°+ y" and 90° + y' respect-
ively. It therefore comes to the same thing, whether the one set of angles
or the other is supposed to be measured. The letter /3 has the same signi-
fication in both notation?.

390 Royal Irish Academy.

divided by the tangent of 2/30, gives 7° 19' for the mean value of s,
the error of the mica-plate corresponding to that part of the spec-
trum which was observed at the incidence of 60°.

At incidences nearer the angle of maximum polarization, the errors
are probably much greater. Beyond that angle they again diminish,
and in some cases they almost vanish. Thus, at the incidence of 85°
upon steel, with the value of 2 0O and the value of 2 Q corresponding
to a = 20°, we get, by computation, a value of 2 fi0> which differs
only by a few minutes from that given by M. de Senarmont. Nearly
the same thing happens at the same incidence when we take a=25°.
In these cases therefore the results belong to that particular ray for
which the thickness of the plate was exact.

The observations of M. de Senarmont on speculum metal were
not carried beyond the incidence of 60°. He states that he was un-
able to observe at higher incidences, on account of the uncertainty
arising from the dispersion of the metal ; but though this cause ope-
rated in some degree, his embarrassment must have been really oc-
casioned by the increasing magnitude of the difference d'—d", as he
approached the angle of maximum polarization ; that difference being
perhaps twice as great as in the case of steel. My own experiments
on speculum metal were all made, as has been seen, at incidences
greater than 60°.

The experiments of M. de Senarmont do not at all agree with the
formulae ; and therefore I have been obliged to analyse his method
of observation, and to show that it could not lead to correct results.
It is to be regretted that his method was defective, as the zeal and
assiduity which he has displayed in the inquiry would otherwise have
put us in possession of a large collection of valuable data.

I shall conclude by saying a few words respecting the intensity of
the light reflected by metals. The formula? for computing this in-
tensity have been given in the Transactions of the Academy, in the
place already referred to ; but they may be here stated in a form
better suited for calculation. If we suppose ^ and \p' to be two
angles, such that

cotan \p = — , cotan \p' — M ju,, .... (O.)

and then take two other angles w, tu', such that

cos w = sin 2 \p cos %, cos w' = sin 2 ip* cos %, . . (P.)
we shall have

r = tan|w, r' = tan^u>' (Q.)

where r is the amplitude of the reflected rectilinear vibration, when
the incident light is polarized in the plane of incidence, and t' is the
amplitude of the reflected vibration when the incident light is polar-
ized perpendicularly to that plane ; the amplitude of the incident
vibration being in each case supposed to be unity. Hence when
common light is incident, if its intensity be taken for unity, the in-
tensity I of the reflected light will be given by the formula

I = | (tan2i w + tan2 i w') (It.)

Tf with the values of M and % determined by my experiments we

Royal Irish Academy. 391

compute, by the last formula, the intensity of reflexion for speculum
metal at a perpendicular incidence, in which case jit = 1, we shall
find I = '583. This is considerably lower than the estimate of Sir
William Herschel, who, in the Philosophical Transactions for ] 800
(p. 65), gives "673 as the measure of the reflective power of his
specula. The same number, very nearly, results from taking the
mean of Mr. Potter's observations (Edinburgh Journal of Science,
New Series, vol. iii. p. 280). It might seem therefore that the
formula is in fault ; but I am inclined to think that the metal which
I employed had really a low reflective power. Its angle of maxi-
mum polarization was certainly much less than that of the speculum
metal used by Sir David Brewster (Phil. Trans. 1830, p. 324), who
states the angle to be 76°, whereas in my experiments it was only
about 73^°; and any increase in this angle, by increasing the value
of M, raises the reflective power. On the other hand, the maximum
value of /3 (when a=45°) was greater than that given by Sir David
Brewster, namely, 32° ; and any increase in /3 tends also to increase
the reflective power. Now it is not unreasonable to suppose that
the highest values of both angles may be most nearly those which
belong to the best specula; and accordingly if we take 76° for the
incidence of maximum polarization, and retain the maximum value
of fi, namely 34° 37', which results from my experiments, we shall
get M = 3*68, x — 66° 16'» and tne value °f * at tne perpendicular
incidence will come out equal to '662, which scarcely differs from
the number given by Herschel.

It is clear from what precedes that the optical constants are dif-
ferent for different specimens of speculum metal, and this is no more
than we should expect, from the circumstance that the metal is a
compound, and therefore liable to vary in its optical properties from
variations in the proportion of its constituents ; but I am disposed to
believe that the same thing is generally true, though of course in a
less degree, of the simple metals, so that in order to render the com-
parison satisfactory, the measures of intensity should always be made
on the same specimen which has furnished the values of M and x-
There is dne metal, however, with respect to which there can be no
doubt that the experiments of different observers are strictly compa-
rable, when it is pure, and at ordinary temperatures ; I mean mer-
cury. For this metal Sir David Brewster states the angle of maxi-
mum polarization to be 78° 27', and the maximum value of /3, when
a =45°, to be 35°; from which I find M = 4-616, x — 68° 13'> and
at the perpendicular incidence, I = "734. Now Bouguer observed
the quantity of light reflected by mercury, but not at a perpendicular
incidence. His measures were taken at the incidences of 69° and
78^°, for the first of which he gives, by two different observations,

637 and "666 ; for the second, by two observations, *754 and "703,
as the intensity of reflexion (see his Traitt d' Optique sur la Gradation
de la Lumiere, Paris, 1760 ; pp. 124, 126). If we make the compu-
tation from the formula, with the above values of M and %, we find
the quantities of light reflected at these two incidences to be, as

nearly as possible, equal to each other, and to seven-tenths of the in-

392 Intelligence and Miscellaneous Articles.

cident light, the intensity of reflexion being a minimum at an inter-
mediate incidence ; and if we suppose these quantities to be really-
equal at the incidences observed by Bouguer, we must take the mean
of all his numbers, which is *69, as the most probable result of ob-
servation. This result differs but little from one of the two numbers
given by him at each incidence, and scarcely at all from the result
of calculation.

The angle at which the intensity of reflexion is a minimum, when
common light is incident, may be found from the formula

(m+m) (c + j) = (M-w) t ifl + »'>-4cos* «

which gives the value of p, and thence that of i. This incidence for
mercury is, by calculation, 75° 15', and the minimum value of I is
•693, which is less than its value at a perpendicular incidence by
about one-eighteenth of the latter. According to the formula?, the
reflexion is always total at an incidence of 90°.

LVIII. Intelligence and Miscellaneous Articles.

ON ABSINTHIC ACID. BY C. ZWENGER.

ACCORDING to M. Braconnot, wormwood (Artemisia absin-
thium, Linn.) contains a peculiar deliquescent uncrystallizable
acid, the ammoniacal salt of which crystallizes in four-sided prisms ;
he has named it absinthic acid.

To obtain this acid in a pure state, a decoction of wormwood
(stalks, leaves and flowers) is to be treated with excess of a solution
of acetate of lead ; a bulky precipitate of a dirty yellow colour is
formed ; the supernatant liquor contains some of the salt in solution,
which is very soluble in free acid ; and ammonia is to be added to it
until it is only slightly acid ; the salt of lead, after being well washed,
is to have three or four times its bulk of water added to it, and then
to be decomposed by hydrosulphuric acid ; and it is requisite that
the vessel which contains the salt of lead should be kept at 140°
to 158° Fahr., in order that the decomposition may be complete.
The liquor separated by the filter from the sulphuret of lead is to be
again precipitated by acetate of lead, and the precipitate obtained is
to be decomposed in the same manner. The filtered liquor is after-
wards evaporated to the consistence of a syrup, and the residue is to
be treated with hot aether until there is no acid reaction ; the aether
is to be separated by distillation, and water is to be poured on the
brown residual mass ; by this an acid resin is precipitated, which,
after a little time, forms a compact deposit on the sides of the vessel ;
this resin is the bitter principle of the wormwood.

The aqueous solution is of a yellow colour, and yields crystals by
evaporation, which are purified with difficulty, either by pressure
between sheets of filtering paper or by repeated crystallization. As
this acid is volatile, it is best purified by dry distillation ; the greater
part of the empyreumatic oil which rises with it may be separated
by the addition of water ; the crystals thus obtained are more readily

Intelligence and Miscellaneous Articles. 393

purified • when the author had afterwards hecome better informed
as to the nature of the acid, he purified it by means of nitric acid ;
the quantity thus obtained is, however, extremely small ; about 40
pounds of wormwood yielding only about 15 grains of pure acid.

Absinthic acid has the following properties : — It has a peculiar
and sour taste, is soluble in water, alcohol and aether, and crystallizes
in small colourless lamina?, mixed with acicular crystals ; it sublimes
without leaving any residue ; the vapour excites coughing ; chlorine
and nitric acid do not alter it. The solutions of salts of lead and
silver are precipitated white by this acid, when neutralized by
ammonia ; with chloride of iron a reddish-brown precipitate is ob-
tained ; the chlorides of barium and calcium and the salts of man-
ganese are not precipitated by it.
It yielded by analysis —

I. II.

Carbon 40-650 40-591

Hydrogen.... 5-409 5' 151

Oxygen 53-941 54-258

100- 100-

Estimating the atomic weight of carbon at 75-88, the author con-
cludes that this acid is constituted of

4 atoms of Carbon 303-416 or 40*955

6 ... Hydrogen. .. 37*438 5*053

4 ... Oxygen 40Q-Q00 53-992

740854 100-
The formula of the salt of silver is

4 atoms of Carbon 303*416 or 14*587

4 ... Hydrogen 24-959 1-200

3 ... Oxygen 300-000 14-423

1 ... Oxide of silver 1451-610 69-790
2079*985 100*
The formula of this acid is therefore C4 H1 O3 + aq, and the equiva-
lent of the anhydrous acid is 627*37.

The author observes that these numbers, as well as the reactions
of this acid, exhibit a perfect agreement with those of the succinic
acid, and that no doubt can exist as to their identity.

The succinic acid in the wormwood is combined with potash ; if
the plant be treated directly with aether, no succinic acid is obtained,
but if it be submitted to dry distillation, the presence of succinic acid
is easily recognised among the products ; it appears, therefore, that
succinic acid exists in wormwood in the state of super-succinate of
potash ; this salt possessing the property of yielding a part of its acid
by dry distillation Journ. de Ph. et de Ch., Fev. 1844.

PROCESS FOR OBTAINING OSMIUM. BY MONS. E. FREMY.

One hundred parts of the residue of the ore of platina were mixed
with three times their weight of nitre, and the mixture was heated
in a crucible to redness for an hour in a wind furnace.

394* Intelligence and Miscellaneous Articles.

After this calcination the mass was poured on a metallic plate ;
this operation was performed in the open air, and it is requisite to
protect the face, for without this precaution the vapour of the osmic
acid would act strongly on the skin.

During calcination with the nitre a certain quantity of osmic acid
is lost, hut it was ascertained that the quantity condensed hy using
a porcelain retort did not compensate for the inconvenience of the
operation.

The fused mass, which contains the osmiate and iridiate of potash,
is treated in a retort with nitric acid, which disengages osmic acid,
and this is condensed in a concentrated solution of potash • the re-
sidue of the distillation is treated with water, which removes the
nitre, and then with hydrochloric acid, which dissolves the oxide of
iridium ; by these means osmium is obtained in the state of osmiate
of potash, and the iridium as a soluble chloride.

The author found, that by disengaging oxygen from osmiate of
potash, and transferring it to other bodies, this salt was readily con-
verted into osmiate of potash, which crystallized in fine octahedrons
of a red colour. This salt contains, in point of fact, an acid which
is less oxygenated than the osmic acid, for by the action of weak
acids it is decomposed into osmic acid and black oxide of osmium.

M. Fremy usually prepares osmiate of potash by pouring a small
quantity of alcohol into a solution of osmiate of potash ; the liquor
becomes hot and of a red tint, and deposits a crystalline powder of
osmite of potash ; in this operation the osmiate of potash is often
totally precipitated from solution. This salt may be washed with
alcohol, which does not dissolve it, and may be kept, when dry, for
an indefinite period ; and it is used by M. Fremy in preparing all the
compounds of osmium.

When osmite of potash is treated with a cold solution of hydro-
chlorate of ammonia, it dissolves at first, and soon decomposes, giving
rise to a new yellow salt, which is nearly insoluble in cold water ;
and this, when calcined in a current of hydrogen, yields perfectly
pure osmium. When this salt is treated with hydrochloric acid, it dis-
engages osmic acid, and yields a chloride of osmium, which, under
the influence of hydrochlorate of ammonia, forms a precipitate of a
minium red colour, and very slightly soluble in water ; this salt may
also be used for the preparation of pure osmium. — Journ. de Ph.
et de Ch., Mars 1844.

EXAMINATION OF THE AFRICAN GUANO.
BY E. F. TESCHEMACHER, ESQ.

To Richard Phillips, Esq.
Dear Sir,
It appears from the various analyses which have been made of South
American and African guano, that among the numerous ingredients
of which it is composed, it is stated in nearly all of them to contain
uric acid combined with ammonia. A parcel of guano, however, which
I had recently occasion to examine, brought from the coast of Africa,

Mr. Teschemacher's Examination of the African Guano. 395

1 found to contain 4 per cent, of humic acid combined with am-
monia, with scarcely a trace of uric acid. The soluble parts of this
guano in water gave a very deep reddish-brown solution, very diffi-
cult to filter. Upon addition of acetic acid a brown flocculent preci-
pitate was produced, possessing all the properties of humic acid. The
solution was left of a light yellow colour, and now passed through
the filter with the greatest facility. From the great resemblance of
the dark brown solution to that of the liquor which runs from dung-
hills, and which is considered to contain the most valuable part of
the manure, I have no doubt that on account of the presence of
humate of ammonia in this guano it will act powerfully upon vege-
tation, in addition to its other ingredients, which are those usually
contained in other guano.

I am, dear Sir,

2 Park Terrace, Highbury, Yours truly,

April 19, 1844. E. F. Teschemacher.

P.S. Subjoined are the results of various analyses of guano.

Dr. Ure. — Peruvian.
Azotized organic matter, including urate of ammonia, and
capable of affording 8 to 17 per cent, of ammonia by slow

decomposition 50

Water 11

Phosphate of lime 25

Ammonio-phosphate of magnesia, phosphate of ammonia,

oxalate of ammonia, containing 4 to 9 per cent, ammonia 13
Siliceous matter

100
Dr. Ure. — African. /

Saline and organic matter, containing 10 per cent, ammonia 50

Water 21-5

Phosphate of lime and magnesia, also potash 26

Silex 1

Sulphate and muriate of potash 1'5

100
Dr. J. Davy. — American and African.

Soluble in water ; destructible by fire, or volatile, as

oxalate of ammonia, diphosphate, muriate of am- Amer. African.

monia and animal matter 41 '2 40*2

Not destroyed by fire ; insoluble ; chiefly phosphate

of lime and magnesia 29 28*2

Not destroyed by fire ; soluble ; muriate of soda, and

carbonate and sulphate of potash 2- 8 6 4

Destructible by fire ; little soluble ; chiefly urate of

ammonia 19

Expelled by drying on steam-bath; chiefly water,

and a little carbonate of ammonia 8 25"2

100 100
No urea, or very little ; no oxalate of lime.

396 Intelligence and Miscellaneous Articles.

Dr. Ure. — Chilian.
Combustible, organic and volatile saline matter, containing

2£ per cent, ammonia 2250

Water 24

Silex -50

Phosphate of lime 53

100
Dr. Colquhoun. — Chilian (the same parcel as above).
Urate of ammonia, ammoniacal salts, and decayed animal

matter 17'4

Phosphate of magnesia and lime ; oxalate of lime 48* 1

Fixed alkaline salts 10*8

Stony matter 1*4

Moisture 223

100
E. F. Teschemacher. — African.

Volatile ammonial salts, viz. oxalate, phosphate and humate
of ammonia, and organic animal matter, containing 5 per

cent ammonia 25

Fixed alkaline salts, consisting of muriate, sulphate and

phosphate of potash 11

Phosphate of lime and phosphate of magnesia 32

Water 30

Earthy matter 2

100
The above contains 4 per cent, humic acid.

RATIO OF THE DRACHM AND GRAIN, AVOIRDUPOIS.
In the British Almanac, from the year 1330, a drachm, avoirdu-
pois weight, is stated to be equal to 27^4 grains. What can this
notation mean? The weight of a drachm is 27*34375 grains, and
if from this "33334, or ^ grain be deducted, there remains of the de-
cimal part •01041, the relation of which to the fraction \ is not ob-
vious. From a Correspondent.

FESTIVAL IN HONOUR OF BERZELIUS.

We have been favoured by a correspondent with the following

notice- Stockholm, 14th Nov. 1843.

Last Saturday we had a festival here of no ordinary interest. A
quarter of a century having just elapsed since our celebrated coun-
tryman Baron Berzelius was appointed Hon. Secretary of the Royal
Academy of Science at Stockholm, which most distinguished situation
he still continues to occupy, the leading members of the Academy,
being anxious to give a public acknowledgement of the great honour
which the name of Berzelius has reflected upon the Academy, and
also the immense services, never to be forgotten, which he during
this long period has rendered to their interests as a scientific body,
resolved that this jubilee should be celebrated within the Academy
in an appropriate manner, due to his illustrious name in the world
of science and literature, not less than to his high rank in society.

Festival in honour of Berzelius. 397

Arrangements were accordingly made for a grand dinner in the
house of the Academy, and His Royal Highness the Crown Prince,
being first honorary member of the Academy, accepted graciously the
invitation to honour the company with his presence on this occasion.
The dinner-table was placed in the spacious hall, which was fitted
up in a very handsome style, with various decorations and other ar-
rangements. The portrait of Baron Berzelius, painted by the well-
known artist, Lieut. -Col. Sodermark, and presented to the Academy
by their present members, in commemoration of this jubilee, was
placed in a conspicuous position, most splendidly illuminated, and
surrounded by palms and some rare and beautiful plants, which made
the appearance very brilliant. His Royal Highness having arrived,
attended by Count Brahe and several other distinguished noblemen,
the numerous assembly sat down to dinner, Baron Berzelius being
placed at the right of His Royal Highness. When the dinner was
over, and the usual loyal toasts being drunk with due honour, His
Royal Highness rose to propose the health of Baron Berzelius, say-
ing in very warm and affectionate terms, that there was none more
entitled to their esteem and admiration than the celebrated Baron,
whose services to science in general, to their native country, and to
this Academy in particular, were beyond all praise, and had already
made his name immortal. His Royal Highness expressed also his
grateful acknowledgement of his own obligations to Baron Berzelius
for the private instruction he had received by him in younger days.
Baron Berzelius returned thanks at great length, and sat down amidst
loud and repeated cheers.

As the name of Berzelius is known over all the world, it may be
of some interest to many of his friends in foreign countries, to have
a short outline of his life. He was born on the 20th August, 1779,
in Ostergothland in Sweden. His father was a clergyman. In com-
mon with Linnaeus, and many other stars in the horizon of science,
it fell also to the lot of Berzelius to struggle against poverty and
many adversities in the earlier part of his life ; but his ardent spirit
and indomitable desire for knowledge overcame all hindrances. At
the age of seventeen he came to the university of Upsala, where he
made very rapid progress in his learning, particularly in his favourite
study, — chemistry. After having passed his examinations he was
promoted Doctor in Medicine, 1804. Having been appointed Medi-
cinal et Pharmacia? Adjunctus at the Collegium Medicum at Stock-
holm, he continued for several years to give public and private in-
struction in chemistry to young students ; and besides, he was
obliged, on account of his small income, to practise occasionally as a
physician. In 1807 he was appointed Medicinae et Pharmacia?
Professor, and in the same year he instituted, in company with seven
other eminent men, the Swedish Medical Society at Stockholm,
which is now highly flourishing, and constitutes the very heart of
the medical profession in Sweden. In 1808 he was called a mem-
ber of the Royal Academy of Science, and officiated as president in
1810. In the same year he was appointed a member of the Royal
Sanatory Board, of which he is now the senior member. In 1818
he was appointed secretary of the Royal Academy of Science. He

398 Festival in honour of Berzelius.

has travelled through several foreign countries for scientific purposes,
viz. to England, 1813 ; to Germany and France, 1819 ; to Bohemia,
1822 ; and to Germany, 1830 and 1835. When the Medico-Chirur-
gical College was established at Stockholm in 1815, Berzelius was
appointed Professor of Chemistry ; and having lately resigned his
place, His Majesty graciously allowed him to remain as Professor
Honorarius, and to retain his salary.

The merits of Baron Berzelius, as regards the science of chemistry,
are so multifarious, that it is quite impossible to comprehend them
within the limits of the present outline. As a proof of the magni-
tude of his laborious pursuits, it may be sufficient to mention, that
he first developed the electro-chemical system, and that he has also
examined and minutely described the atomic theory of the elementary
bodies. Of these bodies he has discovered selenium, thorium and
cerium, and first classified calcium, barium, strontium, columbium,
silicium and zirconium among the metals *. He has discovered and
examined several great classes of chemical combinations, as, for in-
stance, the different degrees in which sulphur combines with fluoric
acid, with platinum, columbium, vanadium, tellurium and phosphorus,
the sulphates, &c. Not less has he distinguished himself by his
experiments in organic chemistry; and properly speaking, he has
laid the foundation of the vegetable and animal chemistry, in par-
ticular the latter. As regards the chemical analysis, the highest
merits are due to him for having arranged a new and generally
adopted chemical nomenclature. The minerals which formerly were
arranged according to their exterior qualities, have been classified
by him with regard to their chemical combinations. From this it
will be seen, that there is hardly any branch of chemistry which he
has not examined, and where he has not made the most important
discoveries.

His works, which have been for the most part translated into the
English, French, German, Italian, Spanish, and Polish languages, are
so numerous and voluminous, that considering the accuracy with
which everything is described, it appears to be almost a wonder
how one man, whose time besides is occupied by a great deal of of-
ficial duties, has been able to accomplish such a mass of scientific
publications. His great work, ' Manual of Chemistry,' has been
published in four different editions, of which the latest contains ten
volumes, the last of which was published in 1 841 . The fifth edition
is now publishing, and two volumes are already in the hands of the
booksellers. His lectures on Animal Chemistry are published in
two volumes ; his works on Natural Philosophy, Chemistry and
Mineralogy, make six volumes ; and his Reports of the yearly pro-
gress of the natural and chemical sciences contain not less than
twenty-three volumes.

* There is some ambiguity here: the metallic nature of calcium, barium,
and strontium was certainly first determined by Sir H. Davy ; and the share
justly claimable by Berzelius in the discovery of the true nature of the other
bodies mentioned appears to be somewhat exaggerated. We forbear fur-
ther remark on account of the strong national and friendly feeling in favour
of the illustrious subject of the notice with which it is written, and of which
he is so eminently deserving. — Edit.

Meteorological Observations. 399

Of eminent men from foreign countries who have worked in the
laboratory of Berzelius, are Bonsdorff, Engelhardt, Gmelin, Hartwall,
Hess, Hiinefeld, Johnston, Magnus, E. Mitscherlich, Nordenskidld,
Osann, G. Rose, H. Rose, Turner, Winckler and Wohler.

Baron Berzelius has received from His Majesty King Charles
John many marks of high distinction, viz. created a nobleman, 1818,
and a Baron, 1835 ; Knight Commander of the royal order of Wasa,
1821, and Grand Cross of the same order, 1829. Besides, he is
Knight of the Royal Swedish order of the Polar Star, and of several
foreign orders received from the Emperor of Russia, and the kings of
Prussia, Denmark, Belgium, France and Sardinia. He is an hono-
rary member of not less than eighty-eight literary and scientific so-
cieties, of which seventy-nine belong to foreign countries. In con-
sideration of the great services which Baron Berzelius has done to
his native country, the members of the last Diet at Stockholm in
1840 voted to him the annual sum of 2000 dollars Banco, as a pen-
sion for his lifetime, independent of his former emoluments.

METEOROLOGICAL OBSERVATIONS FOR MARCH 1844.
Chiswick. — March 1. Cloudy and fine : rain at night. 2. Overcast: squally,
with heavy showers. 3. Cloudy and windy : clear and fine. 4. Constant heavy
rain throughout. 5. Cloudy : clear, with sharp frost at night. 6. Clear and
frosty : overcast : slight frost. 7. Cloudy and cold. 8. Very fine. 9. Cloudy
and mild. 10. Heavy rain. II. Boisterous. 12. Very clear : stormy showers.
13. Clear : cloudy. 14. Heavy rain. 15. Rain: fine. 16. Slight haze : fine.

17. Overcast : boisterous. 18. Clear and cold. 19. Cloudy. 20. Rain. 21.
Clear and fine. 22. Cloudy: rain at night. 23. Fine. 24. Cloudy : boisterous.
25. Overcast. 26. Very fine. 27. Overcast : hazy. 28. Very fine. 29. Dense
fog. 30. Dry haze. 81. Slight haze: clear and fine : foggy at night. — Mean
temperature of the month 00,1 below the average.

Boston. — March 1, 2. Fine: rain early a.m. 3. Fine. 4. Fine: rain p.m.
5. Cloudy. 6. Fine : rain and snow p.m. 7. Cloudy. 8. Fine : rain p.m.

9. Cloudy. 10. Rain. 1 1. Windy : stormy day : rain p.m. 12. Windy : stormy
day : rain and snow p.m. 13. Fine. 14, 15. Cloudy : rain a.m. 16, 17. Cloudy.

18. Fine. 19. Cloudy. 20. Rain. 21. Fine. 22. Cloudy. 23. Cloudy:
rain early a.m. 24. Rain. 25. Cloudy : rain p.m. 26, 27. Cloudy. 28, 29.
Fine. 30. Foggy. 31. Cloudy.

Sandwich Manse, Orkney. — March 1. Thaw: cloudy. 2. Rain: clear frost.
3. Cloudy : clear frost. 4. Snow-showers. 5. Snow : drift-showers. 6. Snow-
showers : cloudy. 7. Bright : cloudy. 8. Rain : damp. 9. Rain : showers.

10. Bright : clear. 11. Showers: snow-showers. 12,13. Snow-showers. 14.
Bright: damp. 15. Bright : clear frost. 16,17. Bright : cloudy. 18. Bright:
damp. 19. Showers : rain. 20. Bright: cloudy. 21. Cloudy : rain. 22. Showers:
clear. 23. Clear. 24. Bright : clear. 25. Drops : clear. 26. Clear : cloudy.
27. Bright : clear : aurora. 28. Clear : cloudy. 29. Clear: aurora. 30. Fine.
31. Mist: aurora.

Applegarth Manse, Dumfries-shire. — March 1. Heavy showers p.m. 2. Very
slight rain. 3. Heavy rain. 4. Fair. 5. Slight shower : snow. 6. Frost a.m. :
fine. 7. Frost. 8. Frost: snow : rain p.m. 9. Sharp showers: rain. 10. Clear
a.m. : rain p.m. 11. Showers of sleet. 12. Frost : snow. 13. Frost: fine. 14.
Rain p.m. 15. Sleet. 16. Frost: fair. 17. Frost : fine. 18. Frost : rain p.m.

19. Showery: sleet. 20. Frost: fine. 21. Rain: hail. 22. Fine. 23. Rain
and hail. 24. Heavy rain. 25, 26. Fine. 27. Very fine: rain p.m. 28. Fine :
frost. 29. Fine spring day. 30. Fine : frost. 31. Fine.

Mean temperature of the month 380,8

Mean temperature of March 1843 40 -7

Mean temperature of twenty years 38 -9

Mean temperature of spring-water 45 *0

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THE
LONDON, EDINBURGH and DUBLIN

PHILOSOPHICAL MAGAZINE

AND

JOURNAL OF SCIENCE.

[THIRD SERIES.]

JUNE 1844.

*

LIX. Experiments on the Heat disengaged in Combinations.
By Thomas Graham, Esq., F.R.S., #c*

Part II. Neutralization of various Acids by Hydrate of Potash.

THE arrangements adopted for observing the heat evolved
on neutralizing acids by potash were similar to those de-
scribed in the former paper. The same platinum crucible,
weighing 1201*9 grains, and hollow cylinder of palladium,
weighing 207'6 grains, were employed as the containing ves-
sel and stirrer ; but the constant quantity of water employed
as a vehicle for the acid and alkali was increased from 1000
grains to 1544 grains, or 100 grammes, while the equivalent
quantities of the substances used were the same as before.
The solution of the saline body formed in an experiment was
consequently one-half more dilute, and the small but sensible
effect of further dilution of the solution in producing cold, ob-
servable in some of the former experiments, was thus entirely
avoided, while the increase of the mass of fluid reduced the
influence of external causes on its temperature. A mercu-
rial thermometer of greater delicacy was employed, of which
the bulb was a cylinder of 1*25 inch in length and 0*3 inch in
diameter; the scale was graduated into degrees Fahrenheit,
ranging from 40° to 70°, each degree being 0*42 inch in length
(0*74 inch for one degree centigrade), divided into tenths of a
degree, each of which could again be subdivided into fifths
by the eye, so that the observation was made to one-fiftieth
of a degree Fahrenheit. The eye was directed to the scale
through a straight cylindrical tube of small diameter, sup-
ported in a horizontal position. The mercury in the bulb of
the thermometer was equivalent in capacity for heat to 11*5

* Communicated by the Chemical Society* having been read January
15, 1844.
Phil Mag. S. 3. Vol. 24. No. 161. June 1844. 2 D

402 Mr. Graham on the Heat disengaged in Combinations.

grains of water, and the containing vessel and stirrer to 49
grains, making together 60*5 grains of water ; the capacity of
the salt dissolved or formed rarely exceeded that of 12 grains
of water.

I. Neutralization of Hydrate of Potash by Nitric and
Hydrochloric Acids.
The equivalent proportion of this acid adopted in these ex-
periments is 33*85 grains, that is one-twentieth of 677, the
usual equivalent of nitric acid on the oxygen scale. Nearly
one-half the quantity mentioned was used in an experiment,
namely 0'455 equivalent, diluted in the crucible with about
four-fifths of the water, while the remaining portion of the
1544 grains of water, in a small and thin glass flask, contained
hydrate of potash in quantity sufficient to saturate the acid,
and leave a slight excess of alkali. The two liquids were af-
terwards brought to exactly the same temperature, which was
observed by two thermometers, the corresponding points of
which were accurately determined, and the potash solution
then emptied into the nitric acid. The following are the re-
sults of three observations of the temperature of the liquids
before mixture, and the temperature after mixture : —
Before mixture . . 61°*91 62°*13 62°*13
After mixture . . . 66°*70 66°-91 66°*89
Rise of temperature . 4°*79 4°*78 4°*76
Increasing 4°*78 the mean of the experiments, in the pro-
portion of 0*455 to 1, we have 10o,50 as the rise of tempera-
ture on saturating a whole equivalent of potash by nitric acid.
The heat evolved upon combination is sensibly affected by
a considerable difference in the temperatures at which the acid
and alkali are mixed ; being less at the lower temperature.
This appears by the following experiments, in which 0*5 equi-
valent of nitric acid was neutralized at a temperature twenty-
two degrees lower than in the former experiments.

Before mixture . . 40°*25 40°*60
After mixture . . . 45°*43 45°* 80
Rise of temperature . 5°*18 5°*20 Mean 5°*19.

Hence we have the heat from the neutralization of nitric
acid by hydrate of potash —

10°* 50, at 62° F.
10°* 38, at 40° F.

Half an equivalent of hydrochloric acid, 11*38 grains, was
neutralized with hydrate of potash in slight excess, exactly as
the nitric acid was treated in the preceding experiment.

Mr. Graham on the Heat disengaged in Combinations. 403

Before mixture . . 60°-20 60°'00 59°'95
After mixture . . . 65°'3Q 650,15 650,10
Rise of temperature . 5o,10 5°' 15 5°' 15
Mean rise 5°'13 for 0*5 equivalent of hydrochloric acid, or
10o,26 for 1 equivalent of that acid. The neutralization of
hydrate of potash, therefore, in very dilute solutions with
these two different acids produces nearly the same disengage-
ment of heat, the result with nitric acid being 10o,50.

The heat of combination appears also to be sensibly affected
in amount by the temperature of the experiment: —
Before mixture . . 40°-00 40°-25
After mixture . . . 45°-02 45°'30
Rise of temperature . 5o,02 5°'05 Mean 5°'03
From which it follows that the heat from the neutralization
of hydrochloric acid by hydrate of potash is —
10°- 26, at 60° F.
10°-06, at 40° F.
It is remarkable how large a proportion the cold produced
on dissolving in water crystallized nitrate of potash and
chloride of potassium, the salts produced in these experiments,
bears to the heat observed in the formation of the same salts.
One equivalent of crystallized nitrate of potash (63*25 grs.)
well dried, pounded and sifted, was dissolved in the usual
quantity of water : —
Before solution . 61°'80 62°-20 61°'88
After solution . . 56°' 10 56°'45 56°' 18
Fall of temperature 5°'70 5°'75 5U>70 Mean 5°«72.
Before solution . 56 *45 57°'70 55°-45
After solution . . 50°-80 52°-00 49°*75

Fall of temperature 5°-65 5°'70 5°'70 Mean 5°-68.
The cold on dissolving this salt is not quite constant, but
increases sensibly at low temperatures, a law which appears
to prevail in a class of salts : —

Before solution . 47o,00 46°-40 45°*95

After solution . . 41°-Q5 40°-47 40°-Q0

Fall of temperature 5°*95 5°-93 5°*95 Mean 50,94.
It appears, on comparing the last set of experiments with
that immediately preceding it, that a difference of ten degrees
at this part of the scale makes a difference of 0o,26, or
l-22nd part, in the fall of temperature consequent upon
the solution of an equivalent of nitrate of potash. It is
this increased absorption of heat at the low temperature pro-
bably which occasions the observed heat of combination of
the salt to diminish at the same part of the scale.

2 D2

404 Mr. Graham on the Heat disengaged in Combinations.

On the other hand, the cold, on dissolving several equiva-
lents of nitrate of potash successively at a constant tempera-
ture, in the same quantity of water diminishes considerably
with the number of equivalents of salt dissolved. The capa-
city for heat of the crystallized salt is 0*239 (Regnault).
Dissolved in 1544 grains of water,
First equivalent of nitrate of potash : —
62°'34 63°*68

56°-68 57°-90

Fall 5°-66 5°-78 Mean 5°'72.

Second equivalent of nitrate of potash: —
63°-47 63°- 12

58°-17 57°'86

Fall 5°-30 5°-26 Mean 5°'28.

Third equivalent of nitrate of potash : —
63°-40 63°'S6

58°-47 58°-61

Fall 4°-93 4°-95 Mean 4°'94.

Fourth equivalent of nitrate of potash : —
63°*57 63°-35

58°-95 58°-76

Fall 4°-62 4°-59

Fifth equivalent of nitrate of potash : —
63°*40 63°-34

59°'Q8 59°-10

Fall 4°-32 4°-24 Mean 4°-28.

Sixth equivalent of nitrate of potash : —
63°*45
69°-63
^ Fall 3°-82
In consequence of this diminished absorption of heat in the
solution of the latter equivalents of nitrate of potash, the ad-
dition of water to the strong solution finally obtained occa-
sions a further absorption of heat; or dilution produces cold.
The last prepared solution, which consisted of 379*5 grains
of nitrate of potash dissolved in 1544 grains of water, and is
a solution nearly saturated for the temperature, was mixed
with another 1544 grains of water in a pint silver crucible
with silver spatula, weighing 1650 grains, both liquids being
at the same temperature : —

Before mixture . . 63°*19
After mixture . . . 61°'91
Fall of temperature . 10,28

Mr. Graham on the Heat disengaged hi Combinations. 405

A second portion of 1544- grains of water being added to
the above solution, occasioned a further fall of temperature : —
Before mixture . . 63°-57
After mixture . . . 63°'19

Fall "0^38

It appears from these experiments on the solution of suc-
cessive equivalents of nitrate of potash in the same quantity of
water, that much of the cold on dissolving that salt is pro-
perly referable to the dilution of the solution, and not to the
simple liquefaction or solution of the crystalline salt. But
this is more obvious in dissolving a salt of great solubility,
such as nitrate of ammonia, of which many more equivalents
may be dissolved in succession.
Dissolved in 1544 grains of water,
100*4 grains, or 2 equivalents of nitrate of ammonia : —
66°-25
57°'91
Fall

Third
lents : —

and fourth equiva-

equiva-

66°-43

58°-91

Fall 7°'52

Fifth and sixth
lents : —

66°-21

59°-36

Fall 6°-85

Seventh and eighth equiva-
lents : —

66°' 10

59°'82

Fall 6°'28

Ninth and tenth
lents : —

66°-26
60°-41
Fall 5°-85
Eleventh and twelfth equi-
valents : —

66°*53

61°-06

Fall 5°'47

equiva-

°-34

Thirteenth and fourteenth
equivalents : —

66°-45

61°-29

Fall 5°-16

Fifteenth and sixteenth
equivalents : —

66°-47

61°-55

Fall 4°-92

Seventeenth and eighteenth
equivalents : —

66°'61

61°-99

Fall 4°'62

Nineteenth and twentieth
equivalents : —

66°*26
61°'91

Fall 4°-35
Twenty-first and twenty-
second equivalents: —
66°-58
62°-45
Fall 4°-l3

406 Mr. Graham on the Heat disengaged in Combinations.

Twenty-third and twenty-
fourth equivalents: —
66°*66
62°-63
Fall 4°'03
Twenty-fifth and twenty-
sixth equivalents: —
66°-83
63°' 16
Fall 3°'67
Twenty-seventh and twenty-
eighth equivalents : —
66°-53
62°-97
Fall 3°-56

Twenty-ninth and thirtieth
equivalents : —

66°'57

63°'24

Fall 3°-33

Thirty-first and thirty-se-
cond equivalents: —
66o,80
63°-57
Fall 3°'23

Thirty-third and thirty-
fourth equivalents : —
66°-37
63°-24
Fall 3°-13

Thirty-fifth and thirty-sixth equivalents: —

66°'45
63°'50

Fall 2°-95
Here we find that while the fall on the solution of the first
two equivalents of nitrate of ammonia is 8°'34, that of the last
two dissolved is only 20,95, or little more than a third of the
former. The liquid, however, finally consisted of 1544 grains
of water and 1807*2 grains of salt, and would therefore have
a considerably greater capacity for heat than the water alone ;
but the proper correction for this increase of capacity cannot
at present be made, as the specific heat of nitrate of ammo-
nia has not been ascertained.

The last solution of nitrate of ammonia, which was nearly
saturated for the temperature, was of density 10,247. Three
portions of 100 gi'ammes of water were added to it in succes-
sion, to discover the cold produced on dilution.
First 100 grammes of water: —
Before mixture .
After mixture . .
Fall

66°'83

60°-27

6°'56

Second 100 grammes of water: —
Before mixture
After mixture . . .
Fall

Third 100 grammes of water: —
Before mixture .
After mixture . . .
Fall

67°*06

64°-40

2°-66

67°'06

65°-61

l°-45

I.

II.

III.

IV.

V.

65°*07

65°*0l

64°*63

64°*80

64°*84

61°*56

61°*70

61°*65

63°* 14

62°*29

3°*51

3°*31

2°-98

2°-66

2°-55

VI.

VII.

VIII.

IX.

X.

64°*77

64°*63

64°*89

64°*77

64°*64

62°*38

62°*34

62°*74

62°*79

62°*76

Mr. Graham on the Heat disengaged in Combinations. 4-07

The high solubility of the nitrate of soda adapts it for si-
milar experiments. It will be observed that a difference of
13 degrees of temperature does not materially affect the
amount of heat absorbed on dissolving a single equivalent of
this salt. The capacity for heat of the crystallized salt is
0-278 (Regnault).

One equivalent of nitrate of soda, 53*40 grains, dissolved in
100 grammes of water: —

Before solution . . 65°-07 51°'78 51°*63
After solution . . . 61°-56 48°*25 48°*08

Fall 3°-51 3°-53 3°'55

Ten equivalents of this salt being dissolved successively in
the same 100 grammes of water, the following changes of
temperature were observed : —

Fall

Fall . 2°-39 2°-29 2°'15 1°'98 1°*88

The solution of the tenth equivalent of this salt produces
therefore only one-half the cold due to the first equivalent.

The solution of chloride of potassium in water is attended
with a fall of temperature, which is considerable, although not
so great as with nitrate of potash.

One equivalent of chloride of potassium (46*62 grains) dis-
solved in 100 grammes of water : —
Before solution . . 62°-05 61°'80 61°*70
After solution . . . 59°* 10 58°*88 58°*75
Fall of temperature . 2°*95 2°*92 2°-95 Mean 2°*94.

At a lower temperature : —
Before solution . . 45°*55 45°*04 45°'S3
After solution . . . 42°*55 42°*02 42°*50
Fall of temperature . 3°*00 3°*02 3°*03 Mean 3°*02.
II. Neutralization of Hydrate of Potash by Sulphuric Acid.

Half an equivalent of sulphuric acid, 12*53 grains, was sa-
turated with a slight excess of hydrate of potash, the united
liquids containing 100 grammes of water, as in the preceding
experiments with nitric and hydrochloric acids : —
Before mixture . . 61°*31 61°*45 61°\53
After mixture . . . 67°*01 67°*13 67°*21
Rise 5°-70 5°*68 5°*68 Mean 5°*69.

408 Mr. Graham on the Heat disengaged in Combinations.

The rise of temperature on saturating a whole equivalent
of hydrate of potash with sulphuric acid will therefore be
ll°-38.

The saturation of sulphate of water, already in combination
with sulphate of potash in the bisulphate of that base, is at-
tended with the disengagement of a still greater quantity of
heat. Half an equivalent of fused bisulphate of potash, dis-
solved in water like the acid of the former experiments, was
neutralized by potash, with the usual conditions : —
Before mixture . . 62°«74 62°-92 63°*05
After mixture . . . 68°'95 69°-12 69°-22
Rise 6°-21 6°-20 6°'17 Mean 6°'19.

The saturation of the whole equivalent of sulphate of water
in a solution of the bisulphate of potash therefore occasions
the disengagement of 12°-38 ; free sulphate of water only
110,38; the excess in the former case being lo,00.

Now, in saturating two equivalents of sulphuric acid, the
heat evolved is twice ll°-38, or 22°»76; but as 12°-38 is
evolved in saturating the second equivalent of sulphuric acid,
it follows that 10o,38 only are evolved in saturating the first
equivalent of acid. Hence we have —

Heat disengaged in the formation of bisulphate of potash 10o,38
saturating acid of ... ... 120,38

22°-76
The cold, on dissolving an equivalent of crystallized sul-
phate of potash, 54>'55 grains, in 100 grammes of water, was

also observed : —

Before solution .

. 66°-69

66°'01

66°«27

After solution . .

. 64°-38

63°-75

63°-96

Fall

2°-31

2°-26

2°-31

Mean 2°-29.

On mixing solutions of sulphate of potash and sulphate of
water (dilute sulphuric acid), to form bisulphate of potash,
cold is produced, as was formerly observed ; and from this
cause sulphate of potash, when dissolved in water acidulated
with sulphuric acid, produces more cold than in pure water,
by about one-third of the quantity from the latter. This ex-
cess of heat absorbed I was disposed to connect with the com-
bination of sulphate of water with sulphate of potash, and for-
mation of a double salt. But it is remarkable that the mag-
nesian sulphates, which we do not certainly know to combine
with hydrated acids, as sulphate of potash does, likewise pro-
duce greater cold on dissolving in acidulated than in pure
water.

Thus an equivalent of crystallized sulphate of magnesia,

Mr. Graham on the Heat disengaged in Combinations. 409

which dissolves in 1000 grains of water with a fall of 0o,88 R.
(Chemical Memoirs, vol. i. p. Ill), dissolved in the same
quantity of water already containing an equivalent of sulphuric
acid with a fall of 1°-12, 1°*17, 1°*18 R. in three experiments;
of which the mean is ]°'16, being 0o,28 more than in pure
water. A second equivalent of crystallized sulphate of mag-
nesia, when dissolved in the same liquor, produced a fall, in
three experiments, of 0°*96, 0°«92, 0°'95 R., of which the
mean is 0o,94, or only 0o,06 more than in pure water.

In an equivalent of nitric or of hydrochloric acid, the fall
from the solution of an equivalent of crystallized sulphate of
magnesia was nearly double what it is in pure water.

The fall in water containing 1 equivalent of nitric acid was
1°-T0, 1°-G8, l°-64, of which the mean is 1°67.

The fall in water containing 1 equivalent of hydrochloric
acid was 1°"70, 1°*70, 1°'68; mean 10<69 R.

The fall on the solution of 1 equivalent of sulphate of
magnesia in ^ equivalent of hydrochloric acid was 10,37,
l°-37, 1°*38; mean 1°\37 R. The excess of cold produced
by the half equivalent of this acid, over water alone, was
therefore 0o,50 ; the excess by the whole equivalent of acid
0o,82 ; so that fully more than one-half of the effect is pro-
duced by the first half equivalent of acid.

An excess above 1 equivalent of acid to 1 equivalent of a
salt of this class increases the depression of temperature still
further, but in a less degree than the direct proportion of its
quantity. Thus the cold on dissolving 1 equivalent of sul-
phate of zinc in water being lc,02 R., —

In H equivalent of sulphuric acid, l°-22, 1°-19, 1°*25 ;
mean l°-22.

In 1 equivalent of nitric acid, 10,56, 1°'55,1°'54; mean \°'55.

In i equivalent of hydrochloric acid, l°-50, 1°*50, 1°*47;
mean 1°*49.

In 1 equivalent of hydrochloric acid, l°-82, 1°83, l°-86 ;
mean l°-83.

In 2 equivalents of hydrochloric acid, 2°-26, 2°-26, 2°*24 ;
mean 2°'25.

The solution of an equivalent of crystallized sulphate of iron
was attended with a fall of temperature, —

In water of l°-06 R.

In 1 equivalent of sulphuric acid, of 1°'28, l°-20, l°-26,
l°-25 ; mean l°-25.

In 1 equivalent of hydrochloric acid, of 1°'69, l°-68, 1°*73 ;
mean 1*°70.

The solution of an equivalent of crystallized sulphate of
copper was attended with a fall of temperature, —

410 Mr. Graham on the Meat disengaged in Combinations.

In water of 0°* 6 3 R.

In 1 equivalent of sulphuric acid, of 00,94, 0°*96, 1°*02;
mean 0°*97 R.

The mixture of an equivalent of sulphate of "mater, 30*68
grains, in 300 grains of water, with another 700 grains of water,
occasioned a rise of 00,09 R. ; with 700 grains of water con-
taining 1 equivalent of hydrochloric acid a rise of 0o,16, and
with 700 grains of water containing 1 equivalent of nitric acid,
0°'00.

The magnesian sulphates generally resemble sulphate of
water in producing heat and not cold on dilution of their
strong solutions. The solutions of the three following salts
were saturated in the cold : —

Sulphate of zinc (density 1*395), with equal bulk of water,
+ 0°*60.

Sulphate of magnesia (density 1*294), with equal bulk of
water, + 0°*60.

Protosulphate of iron (density 1*227), with equal bulk of
water, + 0°*04.

The experiments on the solution of salts in acids leave it
doubtful, whether the additional depression of temperature is
due in every case and entirely to a combination of the salt
with the acid, as it may be supposed to be when sulphate of
potash is dissolved in dilute sulphuric acid, bisulphate of pot-
ash being then formed, or whether it is a consequence of a
partial decomposition of the salt by the free acid to which it
is exposed. The small portion of acid, generally a single
equivalent, which produces the greatest proportional effect,
seems to indicate that combination or decomposition is the
cause, rather than any alteration in the solvent power of the
liquid. The action of hydrochloric acid and of nitric acid is
often the same, and is greater than that of sulphuric acid.
This appears even in the solution of a magnesian chloride in
water and in these acids.

Thus 42*29 grains, 1 equivalent, of the fused anhydrous
chloride of zinc were dissolved in 1000 grains of water with a
rise in two experiments of 3°'42, 3°*45 R., of which the
mean is 30,44 R. In 1000 grains of water containing 1
equivalent of sulphuric acid, with a rise of 30,43, 3a>42,
3°*42 R., in three experiments ; which is nearly the same
result as in pure water. In the same quantity of water con-
taining 1 equivalent of hydrochloric acid, with a rise of 2°-86,
2°*88, 2°-86 ; of which the mean is 2°*87 R., being 0°*57 less
heat than in water alone. The presence of the hydrochloric
acid has therefore occasioned a fall of 0°*57 in the solution of
chloride of zinc, while the action of sulphuric acid is insensible.

Mr. Graham on the Heat disengaged in Combinations. 411

An alkaline chloride was little affected by the presence of
an equivalent of these acids in the water in which it was dis-
solved. Thus chloride of sodium was dissolved with a fall —

In lOOOgrs. water, of0o,57, 0°-60, MeanO°'59R.

... + HC1, of 0°'60, 0°-60, 0°'60, ... 0°'60R.
... + N05, of0°*50, 0°-50,0°'52, ... 0°*51 R.
... +S03, of 0°'50, O0'50, 0°'43, ... 0°'48R.

To obtain light upon this influence of acids on the thermal
phsenomena of the solution of salts, experiments were made upon
two other salts. Sulphate of ammonia without any water of cry-
stallization (1 equivalent, or 41*41 grains) was observed to dis-
solve in 1000 grains of water with a fall of 0°'5L R. In water
containing i HC1, with a fall of 1°-12, 1°-10, and l°-12 R.;
mean 1°*1 1. In water containing HC1, with a fall of 1°*30,
l°-22, l°-28; mean 1°*27 R. In water containing N05, with a
fall of l°-28, 1°*30, l°-30; mean 1°'29 R. In water containing
SO3,withafallof0o-92,0o,92,0o-90; mean0°-92 R. The addi-
tion of a second equivalent of highly diluted sulphuric acid to
the last solution produced a change of temperature in three
experiments of 0o,02, 00,00, 0°'00. The addition of a second
equivalent of sulphate of ammonia to the preceding solutions
of the bisulphate of ammonia, occasioned a fall of 0o,58, 0o,55,
00,60 R. ; mean 00,58, or very little more than in pure water
(00,51). In 1544 grains of water containing 1 equivalent of
acetic acid (32-15 grains), with a fall of 0°-84, O0<78, 0°*81 F.,
of which the mean is 0°*81 F., the experiment being made
at 67° F. In 1 equivalent of oxalic acid (22*64 grains), with
a fall of l°-20, 1°*21 and 1°'22 F., the experiment being made
at 65° F. To render the last two experiments comparable
with the former, they must be reduced in the proportion of
19 to 13, that is, the effect of the acetic acid to 0°'55 R., of
the oxalic acid to 0°*83 R. ; so that the influence of the acetic
acid is almost nothing, of the oxalic acid much less than that
of the mineral acids.

While 1 equivalent of nitrate of potash was dissolved in
1000 grains of water at 63° F., with a fall of 3°'76, 3°*72 and
30,80 R., of which the mean is 3°*76 ; it was dissolved in the
same quantity of water containing 1 equivalent of nitric acid
at 67° F., with a fall of 30,64, 3°-54, 3°'64 R., of which the
mean is 3°*57 ; in the same quantity of water containing 1
equivalent of sulphuric acid at 58° F., with a fall of 30,53,
3°-50, 30,50 R., of which the mean is 3°*51.

The mere mixing of solutions of such neutral salts as are
understood to combine together and form a double salt, is not
attended with such changes of temperature. No sensible

412 Mr. Graham on the Heat disengaged in Combinations.

b"b"

change of temperature was perceived on mixing dilute solu-
tions of a magnesian and potash sulphate; and one of these
salts was dissolved in a solution of the other with the same fall
of temperature as in pure water. Although I think it all but
certain that these salts combine at once on mixing, I could
not discover a single circumstance which was decisive of the
fact. The density of such a mixture of salts was not altered
by boiling it alone or with spongy platinum, and was exactly
the same as that of the liquid formed on dissolving in water a
corresponding quantity of the crystallized double sulphate.
The addition of an equivalent of sulphuric acid already highly
diluted to each of the solutions thus compared, produced
exactly the same fall of temperature. On the other hand,
this fall of temperature was as nearly as possible the same
as that obtained on dividing the acid into two equal portions,
and mixing separately a solution of each of the constituent
salts with each portion. The solution of a double salt appears
therefore to be as nearly as possible equivalent to the consti-
tuent salts dissolved apart. Even in the formation of alum
no certain change of temperature was observable ; one-fourth
of an equivalent of sulphate of potash (13*63 grains), when dis-
solved in 1000 grains of water, producing a fall of 00,32 R.,
while when dissolved in 1000 grains of water containing one-
fourth of Al3 03 + 3 S03, the fall was 0°'35, 0°32, 0°35 R.,
of which the mean is 00,34 ; the experiments being made at
57° F.

But these double sulphates being all less soluble than their
constituent sulphates, it was desirable to make the experiment
upon the formation of a double salt, which is more solu-
ble than its constituents ; such as the double chloride of mer-
cury and ammonium. One-half of an equivalent of chloride
of mercury, 42'70 grains, was dissolved in 1544 grains of
water at 64° F., with a fall of 0°-29, 0°-30, 0°"30 F., of which
the mean is 0o,30 F. The same quantity of chloride of mer-
cury was dissolved in 1544 grains of water, containing half
an equivalent, 16*74 grains, of chloride of ammonium, at
63° F., with a fall of 0°'13, 0°-12, 0°*12 F., of which the
mean is 0°*12 F. Doubling these results, we have the fall
from a whole equivalent of chloride of mercury in water equal
to 0o,60 ; from chloride of mercury in chloride of ammonium
0o,24 ; the difference, or 0°*36, being due to heat evolved in
the formation of the double salt. The latter, however, or
sal-alembroth, assumes an atom of water of crystallization in
its formation, which may perhaps occasion some change of
temperature.

When 1 equivalent of chloride of mercury was dissolved

Mr. Graham on the Heat disengaged in Combinations. 413

in half an equivalent of chloride of ammonium at 63°, the fall
was 0°*45, 0°*45, 0°*47 F., of which the mean is 0°*46 F.
The disengagement of heat in the formation of this second
double salt is therefore 0°*60-0°*46 = 0°*14 F. It is doubt-
ful whether the heat here can be ascribed to hydration ; as
the resulting double salt has been crystallized at the usual
temperature by Dr. Kane, both anhydrous and with one atom
of water. The circumstance however of the chloride of mer-
cury being dissolved by a solution of sal-ammoniac in much
larger quantity than by pure water, affords a proof of the im-
mediate formation of a double salt on the solution of its con-
stituents together, which cannot be obtained in the magne-
sian or aluminous double sulphates.

I may be allowed to place under the present head of sul-
phuric acid, the results of experiments on the solution in water
of two double sulphates, namely sulphate of zinc and soda,
and sulphate of manganese and soda, no experiment on a
double salt of the soda division of this class being recorded
in the former paper. The sidphate of zinc and soda, formed
by Mr. Arrott, was in excellent crystals, containing four atoms
of water ; of which the composition is expressed by the for-
mula ZnO, S03 + NaO, S03 + 4 HO. One-half of an equi-
valent, 58*61 grains of the salt, containing 11*25 grains of
water of crystallization, was dissolved in 988*8 grains of water
at 62° F., with a fall in three experiments of 0°*02 R., 0°*04,
0°*02 ; mean 0°*03 R.

Of the same salt made anhydrous by heat and fused, half
an equivalent, or 47*41 grains, was dissolved in 1000 grains
of water at 62° F., with a rise in three experiments of 1°*86,
1°'87, 1°*84; mean 1°*86 R. Doubling the results of the ex-
periments in both cases, to obtain the changes for a whole
equivalent, we find —

Cold on solution of ZnO, S03 + NaO, SO3 + 4HO 0°*06 R.
Heat on solution of ZnO, S03 + NaO, SOs 3°'72 R.

As the two sulphates, in all the double sulphates of this class
containing sulphate of soda, crystallize apart when the salt
is dissolved in water at 62°, the double salt is probably de-
composed in these experiments ; and the circumstances of its
solution may therefore be very different from those of a mag-
nesian double sulphate containing sulphate of potash.

The sulphate of manganese and soda, for which I am also
indebted to Mr Arrott, was in good crystals containing two
atoms of water; the formula of this salt being MnO, S03 +
NaO, S03 + 2 HO. 1 equivalent of the crystallized salt,
103*2 grains, containing 11*25 grains of water of crystalliza-

414 Mr. Graham on the Heat disengaged in Combinations.

tion, was dissolved in 988*8 grains of water, with a rise of tem-
perature in three experiments of 0°*77, 0°*70, and 0o,70 ; of
which the mean is 0o,72 R.

Of the same salt, fused by heat and anhydrous, 1 equivalent,
91*95 grains, was dissolved in 1000 grains of water, with a rise
in two experiments of 30,02 and 20,99; of which the mean is
3°*00 R. The results, therefore, for this double salt, are —

Heat on solution of MnO, SOa + 2 HO . 0°*72
MnO, SOa .... 3°*00

III. Neutralization of Bichromate of Potash by Hydrate of

Potash.

Half an equivalent of bichromate of potash, 47*34 grains,
and a little move than half an equivalent of hydrate of potash
contained separately in different portions of the usual quantity
1544 grains or 100 grammes of water, were brought to the
same temperatures exactly, and mixed in two experiments : —

Before mixture . . 63°*23 63°*50
After mixture . . . 67°*71 67°*97
Rise of temperature . 4°*48 4°*47

Doubling 4°*48, the mean result, we have 8°*96 F. as the
heat evolved on neutralizing the second equivalent of chro-
mic acid in bichromate of potash,

Of the neutral or yellow chromate of potash, which is the
product of this neutralization, 1 equivalent, 62*08 grains, was
dissolved by 1544 grains of water at 65° F., with a fall in
three experiments of 1°*82, 1°«81 and 10,87, of which the
mean is 1°*83.

IV. Neutralization of Acetic Acid by Hydrate of Potash.

Half an equivalent of acetic acid, 16*08 grains, was neutral-
ized by potash in very slight excess, as in the other experi-
ments : —

Before mixture . . 63°*52 63°*81 63°*94

After mixture . . . 68°*68 68°-98 69°* 12

Rise of temperature . 5°*16 5°*17 5°*18

The mean result of these experiments 5°*17 being doubled,

we have 10°*34 F. as the heat evolved on the saturation of

acetic acid by hydrate of potash.

Of acetate of potash fused without becoming black, 1 equi-
valent, 61*65 grains, was dissolved in 1544 grains of water at
65° F., with a rise of temperature in three experiments of
2°*45, 2°*47, 2°*44 ; of which the mean is 2°*45 F.

Mr. Graham on the Heat disengaged in Combinations. 415

V. Neutralization of Oxalic Acid by Hydrate of Potash.
Half an equivalent of oxalic acid was neutralized by potash
under the usual circumstances: —

Before mixture . . 64°*60 64°*66 64°*69

After mixture . . . 69°*84 69°*89 69°*95

Rise of temperature . 5°*24 5°*23 5°*26

Doubling 5°*24, the mean result, we have 10°*48 F. as the

heat evolved on the saturation of a whole equivalent of oxalic

acid by hydrate of potash.

One equivalent of crystallized oxalic acid, 39 '50 grains,
containing 12*5 grains of water of crystallization, was dissolved
in 1533 grains of water at 67° F., with a fall of 3°*04, 3°*06,
3°*04 ; of which the mean is 3°*05.

One equivalent of oxalate of water deprived of its water of
crystallization, 28*25 grains, was dissolved in 154-4 grains of
water at 67° F., with a fall of 0°*99, 0°*99, l°*0l ; of which
1°*00 is the mean. The difference between the falls on solu-
tion of the hydrated and anhydrous oxalate, is occasioned by
the hydration of the latter on solution. The heat disengaged
when oxalate of water combines with its two atoms of consti-
tutional water is therefore 3°*05 — lc*00 = 2°*05 F.

Neutral oxalate of potash crystallizes with a single atom
of water, which requires a heat of 212° to expel it. 1 equi-
valent of the crystallized salt, 57*76 grains, containing 6*25
grains of water, was dissolved in 1538 grains of water at 67° F.,
with a fall of 2°*65, 2°*66 and 2°*67 ; of which the mean is
2°*66 F.

Of the same salt made anhydrous by heat, one-half of an
equivalent, 25*75 grains, was dissolved in 1544 grains of water,
with a fall of 0°*76, 0°*71, 0°*74; of which the mean is 0°*74.
A whole equivalent of the salt would therefore have dissolved
with a fall of 1°*58, which is 1°*08 less than the fall from the
hydrated salt. The last quantity represents the heat of com-
bination of oxalate of potash with one atom of water of cry-
stallization. It approaches nearly to one-half of the heat
disengaged by oxalate of water, in combining with two atoms
of water, one-half of 2°*05 being 1°*025 ; the difference is
within the errors of observation.

When hydrated oxalate of potash is dissolved in water
containing oxalic acid, the change of temperature is very
much the same as in pure water, although in the former case
a superoxalate will be formed. One-fourth of an equivalent
of oxalate of potash, 14°*44 grains, was dissolved in 1544
grains of water containing in solution one-fourth of an equi-
valent of hydrated oxalic acid, at 67° F., with a fall of 00,70,

416 Mr. Graham on ike Heat disengaged in Combinations.

0°'68, 00,68; mean 0°*68 F. If it were therefore possible to
dissolve a whole equivalent of the salt in a whole equiva-
lent of the acid contained in the quantity of water to which
we are restricted, the fall would be four times greater, or
2°*72 F., which is nearly the same as the cold on dissolving
crystallized oxalate of potash in water, namely 2°*66. Here
again little or no heat is observed in forming a double salt, for
the binoxalate of potash must be regarded as such.

Binoxalate of Potash. KO, C2 Os + HO, C2 03, 2 HO.—
As with bisulphate of potash, the saturation of the excess
of acid in this salt causes the disengagement of more heat
than the saturation of the same quantity of free acid. One-
fourth of an equivalent of the crystallized binoxalate, 22*91
grains, was neutralized by hydrate of potash at 67°: —

Before mixture . . 66°*80 66°*85 66°*96
After mixture . . . 69°*91 69°*96 70°*04
Rise of temperature . 3°*11 3°-ll 3°*08 Mean 3°*10

The mean quantity, multiplied by four, gives 12°*40 F.,
as the heat evolved on neutralizing by potash the second
equivalent of oxalic acid in binoxalate of potash. Now dis-
tributing the heat from the saturation of two equivalents of
oxalic acid, 20°*68 ( = 10o,34 x2), as was done in sulphuric
acid, we have —

Heat disengaged in the formation of binoxalate of pot. 8°*28
in saturating acid of binoxalate of pot. 12o,40

20°-68

One-fourth of an equivalent of binoxalate of potash, 22*91
grains, containing 6*25 grains of water of crystallization, was
dissolved in 1538 grains of water at 64° F., with a fall of 1°*65,
1°*66, 1°*65 ; mean 1°*65 F. The mean result multiplied by
four, gives 6°*60 F, as the fall on dissolving a whole equivalent
of binoxalate of potash in water. This is 0°*89 more than the
sum of the falls on dissolving the constituent salts separately,
2°-66 + 3°*05 being equal to 5°*71 only.

Quadr oxalate of Pot ask. KO, C2 Os + HO, C2 Oa + 2
(HO, C2 03 + 2HO). — Four-sixths of an equivalent of hy-
drated oxalic acid, 26*22 grains, were mixed with one-sixth
of an equivalent of potash exactly to form this salt: —

Before mixture . . 64°*25 64°*23 64°*25
After mixture . . . 66°*01 66°'Q1 65°*99
Rise of temperature . 1°*76 1°*78 1°*74

The mean result 1°*76 multiplied by six, gives 10o,56 as the
heat evolved in the formation of quadroxalate of potash; that
is, in the saturation of 1 equivalent of potash by 1 of oxalic

Mr. Graham on the Heat disengaged in Combinations. 417

acid, and the further combination of that oxalate of potash
with 3 equivalents of oxalate of water. This rise of tempera-
ture is nearly the same as that in the formation of neutral
oxalate of potash, namely 10o,48.

To observe the heat disengaged on neutralizing quadroxa-
late of potash by hydrate of potash, one-sixth of an equivalent
of that acid salt in solution was mixed with three-sixths of an
equivalent, or rather more, of the alkali, so as to form neutral
oxalate: —

Before mixture . . 64°-19 64°-20 64°-51
After mixture . . . 69°-38 69°-42 69°-71
Rise of temperature . 5°'19 5°-22 5°-20

Doubling 5°*20, the mean result, we have 10o,40 F. as the
heat disengaged on saturating 1 equivalent of potash by each
of the 3 atoms of oxalate of water in the quadroxalate of
potash,

0'192 equivalent (30*70 grains) of quadroxalate of potash
was dissolved in 1540 grains of water at 63°, with a fall of
2°-02, 2°-13, 2°-14; of which the mean is 2°-10F. This gives
by calculation a fall of 10o,93 for the solution of a whole equi-
valent of quadroxalate of potash, which is 0o,88 less than the
fall of its constituent salts dissolved separately, 2°*66 with three
times 3o,05 amounting to 11°\81.

The different oxalates enumerated appear to absorb quan-
tities of heat, on dissolving, which have a simple relation to
each other. Thus, dividing the different falls of temperature
by 0o,88, a number which has more than once presented
itself in the discussion of these experiments, we obtain a set of
ratios given in the second column ; and which, being multi-
plied by two in the third column, approach nearly to round
numbers : —

Cr. oxalate of potash . .
Cr. oxalic acid ....
Cr. binoxalate of potash .
Cr. quadroxalate of potash

VI. Neutralization of Bicarbonate of Potash with Hydrate of

Potash.
Half an equivalent of the crystallized salt, 31*38 grains,
dissolved in water, was neutralized with hydrate of potash: —

Before mixture . . 67°'28 67°"93 67°*68

After mixture . . . 70o,66 710,24 710,03

Rise of temperature . 3°*38 3°*31 3°-35

Phil. Mag. S. 3. Vol. 24. No. 161. June 1844. 2 E

I.

II.

III.

on solution.

Ratios.
3-02

Ratios.

2°-66

6-04 6-

3°'05

3-47

6*94 7*

6°'60

7'50

15-00 15'

10°-93

12-42

24-84 25'

418 Mr. Graham on the Heat disengaged in Combinations.

Doubling 3°*35, the mean result, there is obtained 6o,70 as
the heat disengaged on saturating the second proportion of
carbonic acid in the bicarbonate of potash.

One equivalent, 62*76 grains, of the crystallized bicarbonate
was dissolved in 100 grammes of water at 67°, with a fall in
three experiments of 30>68, 30,69 and 3°*74 ; mean 3°*70.

One equivalent of anhydrous carbonate of potash was dis-
solved in 100 grammes of water at 67°, with a rise in three
experiments of 2°-48, 2°*43 and 2°«47 ; mean 20,46. The heat
evolved on dissolving anhydrous acetate of potash is nearly
the same, being 2°*45.

VII. Neutralization of Arsenic and Phosphoric Acids by

Hydrate of Potash.
Half an equivalent of arsenic acid, 36'00 grains, in solution
as usual, was mixed with exactly half an equivalent of hydrate
of potash, to form the binarseniate of potash (2 HO, KO,
AsOs):—

Before mixture . . 63°*04 63°-19 63°-29

After mixture . . . 68°-14 68°-30 68°-38

Rise of temperature . 5°-10 5°-ll 5o,09

Doubling 5o,10, the mean result, we obtain 10°*20 F. as

the heat disengaged by neutralizing 1 equivalent of potash in

the formation of binarseniate of potash.

One-fourth of an equivalent of arsenic acid, 18*00 grains,
was mixed with exactly half an equivalent of potash, to form
arseniate of potash (HO, 2KO, AsOs) : —
Before mixture . . 63°-27 63°*33 630,42
After mixture . . . 67°'87 67°'94 68°-Q5
Rise of temperature . 4°*60 4°-61 4°*63 Mean 4°*61.
Twice 4°*61, or 9°*22 R, is therefore the heat disengaged
on neutralizing 1 equivalent of hydrate of potash in the for-
mation of the neutral arseniate of potash.

The same salt was formed by mixing together solutions of
half an equivalent of binarseniate of potash, 56*37 grains, and
exactly half an equivalent of potash : —

Before mixture . . 64°*28 64°-27 64°*20

After mixture . . . 68°-31 68°-33 68°-26

Rise of temperature . 4°-03 4°-06 4°-06

Taking 4o,05 as the mean, we have twice that quantity, or

8o,10 F., as the heat disengaged on neutralizing 1 equivalent

of potash with the acid in binarseniate of potash.

On forming the subarseniate of potash (3KO, As05), by
mixing together solutions of one -sixth of an equivalent of
arsenic acid and exactly half an equivalent of potash : —

Mr. Graham on the Heat disengaged in Combinations. 419

Before mixture . . 63°'41 63°-50 63°'50

After mixture . . . 670,40 67°'52 67°'49
Rise of temperature . 4°'09 4o,02 3°'99

Doubling 4o,03, the mean result, we have 8o,06 F. as the
heat disengaged in the formation of one-third of an equivalent
of subarseniate of potash, or in the neutralization of each of
3 equivalents of potash by a single equivalent of arsenic acid.
Hence the successive addition of 3 equivalents of potash to
1 of arsenic occasions the following disengagements of heat :—
By first KO 10o,20; formation of binarseniate of potash.
... second KO 8o,10; formation of arseniate of potash.
... third KO 5°*88; formation of subarseniate of potash.
24°'18 = 8*06 X 3.
Of hydrated phosphoric acid, which had been boiled in
water for a considerable time to render it fully tribasic, half
an equivalent was mixed with half an equivalent of potash, to
form biphosphate of potash (2HO, KO, P05) :—

Before mixture . . 64°'00 64°'00 64°'03
After mixture . . . 69°'01 68°-99 69°'02
Rise of temperature . 5°-01 4°-99 4°«99

Taking 5o,00 as the mean, we have 10o,00 F. as the heat
disengaged on saturating 1 equivalent of potash with 1 equi-
valent of phosphoric acid in the formation of biphosphate of
potash, containing KO + 2HO as bases.

By mixing one-fourth of an equivalent of phosphoric acid
with half an equivalent of potash, phosphate of potash (HO,
2KO, P05) was formed :—

Before mixture . . 64°'00 63°-61 63°-63

After mixture . . . 68°-49 68°-08 68°-18

Rise of temperature . 4°'49 4°*47 4°-55

Doubling the mean result, 4°*50, we have 9°'00 F. as the

heat disengaged in forming half an equivalent of neutral

phosphate of potash, or in saturating each of 2 equivalents of

potash by 1 equivalent of phosphoric acid, in the formation of

phosphate of potash.

The same phosphate of potash was formed by mixing solu-
tions of half an equivalent of biphosphate of potash with half
an equivalent of potash : —

Before mixture . . 64°-06 64°- 14 64°- 15

After mixture . . . 68°-09 68°- 15 68°' 16

Rise of temperature . 4°-03 4°-01 4°-01

Doubling 4°*02, the mean result, we have 8°-04 F. as the

heat disengaged on saturating an equivalent of potash with

the acid of biphosphate of potash.

2 E 2

420 Professor Latham on Phonetics.

To form the subphosphate of potash (3KO, P05), one-sixth
of an equivalent of phosphoric acid, 7-43 grains, was mixed
with half an equivalent of potash : —

Before mixture . . 63°-61 63°'67 63°-69

After mixture . . . 67°'87 67°'93 67°-99
Rise of temperature . 4°*26 4°-26 4°-30

Twice the mean result, 4°-27, is 8°*54 F., which is the heat
disengaged on neutralizing each of 3 equivalents of potash by
a single equivalent of phosphoric acid.

The heat therefore disengaged in the gradual saturation of
phosphoric acid by 3 equivalents of potash may be thus dis-
tributed : —
By first equivalent of potash . . 100,00
... second ... ... . . 8°-08

... third . . 7°'54

25°'62 = 8'54 X 3.

LX. Facts and Observations relative to the Science of Phonetics.
By Professor Latham. (No. III.)

TN two preceding Numbers the connection was indicated be-
•*- tween the mutes and the liquids, on the one hand, and the
mutes and the semivowels on the other. In respect to this
latter connection, it was stated that the sounds of p, b, J' and v
formed a sequence with the sound of w; and that the same
took place between the sounds allied to k and g, and the sound
of the semivowel y. Hence the sequences
p b f v
k g v. y

Beyond this, however, there is an undoubted sequence be-
tween the semivowels and the vowels. W is connected with
the oo in look', y with the ee in feet. This is the fact that gives
to the semivowels their name of half vowel; the sequence having
been universally recognised.

In this connection of the semivowels {y and w) with the

vowels {ee and oo) on the one side, and with the mutes (y and

v) on the other, we find the connecting link between the vowels

and the consonants generally. Hence we have the sequences

p b f v J w u (= oo in look)

k g k y I y i (= ee in feet)

This circumstance gives a prominent character to the vowels
i and w, and also to the series of mutes wherein v and g occur.
It does not, however, give the affinities and sequences of the
vowels. This, however, we know ; for without going further
back than the researches of Professor Willis, as explained in

to

y

Professor Latham on Phonetics,

421

the Transactions of the Philosophical Society at Cambridge
(vol. iii.), we get the order of the vowels as established on
acoustic principles. The four sounds of the

1. a, as in fate, = as,

2. e, as in feet, = /,

3. oo, as in look, =s o,

4. o, as in note, = u,

are shown to be in sequence. Between, however, each of the
vowels in question there are certain intermediate sounds. Thus
the e fermee of the French (common in most tongues) is in-
termediate to 1 and 2.

The il of the Germans = u French, — y Danish, is inter-
mediate to 2 and 3.

The o chiuso of the Italians is intermediate to 3 and 4.
Hence the full sequence is as follows: —

1. a, as in fate, = a?.

2. e fermee, French, = at*

3. ee, as in feet, m i.

4. The German u = il.

5. The oo, as in look, — u.

6. The o chiuso = 6.

7. The o in note = o.

This is all, in respect to the system of the vowels, that the
author feels certain of. The further questions as to the places
of the a in father, and of the u in but, are open to fuller inves-
tigation. Besides this, there also remains open to closer re-
searches, the question as to whether the arrangement of the
vowels is linear or circular, that is, whether the extreme sounds
of the o (as in note) and of the a (as in fate) may not be in the
same relation to each other as ai and i, i and il, &c, or at least
as eg and i, i and u, u and o respectively.

Now assuming for the present a linear arrangement of the
vowels beginning with the a in fate, and ending with the o in
note ; considering also that it is only with the consonants akin
to v and g that a sequence with the vowels is recognised ;
omitting, moreover, the intermediate sounds of a!, il and 6 for
the sake of precision, we have for the articulations that have
fallen within our inquiries the following arrangement, ex-
hibiting a series of sequences rather than any symmetrical
system : —

ce = a in fate.

i ■=■ ee in feet.

u = oo in look.

o — o in note.

or else,

*

* * * *

*

m

*

k g x y

P b f v

* * * *

y

*

n

t d J> S

*

r

s z cr £

*

422

Mr. Grove on the Gas Voltaic Battery.

or else,

r

s z <r £

*

*

*

* * * *

*

<z

I

m
*

Jc g x y
p b f v

* * * *

y

10

*

i
u
o

n

t d \> $

*

*

n

t d \ $

*

*

r

s z <r £

*

*

*

* * * *

*

<E

I
m

*

h g % y
p b f V

* * * *

y

*

I
U
0

These sequences read both ways, i. e. either horizontally or
vertically. The vertical ones, however, are often indistinct,
and got at rather by inference and analogy than by the direct
testimony of the sounds themselves. Thus the connection be-
tween p and b is clearer than that between m and n, this latter
being clearer than the affinity between / and m. The sequence
of the vowel, expressed by the horizontal lines, is, however, very
distinct.

Such is the amount of sequences which seem to the author
sufficiently distinct to claim recognition as the groundwork of
phonetic researches. The peculiar transition to the vowels on
the part of the sounds of series k and p, the affinity with the
consonants on the part of the vowels i and u, and certain pe-
culiarities of the mutes s and z, combined with the rudimentary
character of the present arrangement, indicate the probability
that further researches will give a more general expression to
the affinities in question.

LXI. On the Gas Voltaic Battery. — Experiments made with
a view of ascertaining the rationale of its action and its ap-
plication to Audiometry. By W. R. Grove, Esq., M.A.,
E.R.S., Professor of Experimental Philosophy in the London
Institution.

(Continued from p. 354 and concluded.)
TT now occurred to me that as several of these gases (take
as an instance nitrogen) were absolutely without effect in
the gas battery, this would form a valuable instrument for the
analysis of atmospheric air or other mixed gases. I there-
fore procured,

Experiment 24, — Two narrow cubic inch tubes of seven
inches long, carefully graduated into 100 parts. These were
* For the power of these signs see Phil. Mag. for February 1841.

Mr. Grove on the Gas Voltaic Battery.

423

immersed in separate vessels of dilute sulphuric acid, and
filled with atmospheric air exactly to the extreme graduation ;
the water mark within the tube was examined when exactly at
the same level as the exterior surface of the liquid ; folds of
paper were used to protect them from the warmth of the
hands, and thus prevent expansion ; the barometer and ther-
mometer were examined, and every precaution taken for ac-
curate admeasurement. One of these tubes was left empty in
order to ascertain, and eliminate from Fig. 12.

the result, the effect of solubility. Into «

the other was placed a strip of platinized
platinum foil, one quarter of an inch
wide. This strip of foil was connected
by a platinum wire with another strip
placed in a tube of hydrogen and in-
serted in the same vessel. The appa-
ratus is shown in fig. 12. After the
circuit had been closed for two days,
the liquid was found to have risen in
the tube a twenty-two parts out of the
100 ; in the tube placed by its side, it
had risen one division. The tubes
were allowed to remain several days
longer, but no further alteration took
place. This analysis gives therefore
twenty-one parts in 100 as the amount
of oxygen in a given portion of air.

Experime?it25. — The tube a (fig. 12)
was charged with nitrogen to a given
mark, and 0*5 cubic inch of pure hydrogen added, the tube h
was then charged with oxygen, and the circuit closed. Exa-
mined after twenty-four hours, the water had risen in the tube
a exactly 0\5 cubic inch. The apparatus was left in this state
for several days, but without any further effect; the voltaic
action had thus perfectly exhausted the hydrogen and there
stopped.

These experiments are sufficient to prove the accurate eu-
diometric action of the gas battery ; performed on a large scale
this method of eudiometry appears to me likely to possess
some advantages. In the eudiometer of Volta, when gases
containing oxygen are to be analysed, if the hydrogen added
for detonation be impure, the result is of course erroneous.
The same may be said of the detonation by spongy platinum,
or by a wire heated by a voltaic current, which I formerly
proposed*".

» Phil. Mag., August 1841, p. 99.

424 Mr. Grove on the Gas Voltaic Battery.

If, on the other hand, gases containing hydrogen are to be
analysed, errors may result from any impurities in the oxygen
which is added, or from inaccuracy in the measurement of
either gas ; in the electrolytic method of eudiometry, the
quantity or purity of the hydrogen, in the one case, is of no
importance, and in the other, the quantity or purity of the
oxygen, that is, provided there be sufficient to exhaust the
equivalent to be abstracted from the mixed gas subjected to
eudiometry.

It should be observed, that in these experiments only a
single pair of the gas battery can be used, as, if more be em-
ployed, the electrolyte is likely to be decomposed, and gas
added to the compound*. The process is rather slow, but I
think very sure. Another valuable application of this process
is, that it affords (in experiment 24) a simple method of ob-
taining nitrogen of unquestionable purity. I know of no
method which effects this object so perfectly. All the oxygen
of the air is abstracted, as well as that free oxygen which may
be contained in the liquid ; and by subsequently introducing
a little lime-water into the tube «, the trifling quantity of car-
bonic acid may be removed, or the same thing may be at once
effected by using caustic potash as the electrolyte in the appa-
ratus fig. 12.

Probably many other applications of the gas battery may
suggest themselves to other experimentalists, and obviously
many more changes may be rung upon the gases employed,
and curious and valuable results obtained; I have, however,
in this paper given a sufficient number of experiments fairly
to open the subject ; each appears so suggestive of new ones
that it is difficult to know where to stop.

The experiments on eudiometry, which 1 have last named,
induced me to refer to Dr. Henry's paper on Gaseous Ana-
lysis f5 and on reading it I was struck with a coincidence be-
tween the action of spongy platinum on mixed gases and the
gas battery, a coincidence strongly confirmatory of the views
which led me to its discovery. I will endeavour briefly to
state these, and I state them, not as being absolutely correct,
for differences of opinion may exist on this as on every other
scientific matter, but as being those which existed in my mind
prior to the experiments, and which are considerably, and to
me unexpectedly, strengthened by the results embodied in the
above-mentioned paper of Dr. Henry.

My original deduction may be stated and exemplified as
follows: — When pure or amalgamated zinc is immersed in
acidulated water, the oxygen, as is well known, will not com-
* See Postscript. f Philosophical Transactions, 1 824.

Mr. Grove on the Gas Voltaic Battery. 425

bine with the zinc; but touch both zinc and liquid with pla-
tinum, and combination ensues, the platinum being unaltered.
So with a mixture of oxygen and hydrogen, the gases, although
in intimate contact, will not chemically unite, but touch them
with clean platinum and more or less rapid combination ensues.
Here also the platinum is unaltered. Leaving out of the case
any purely hypothetical explanation, why may not effects so
similar in their character be related in other respects? In
the voltaic combination the platinum is heated during action,
and if the surfaces, and consequently the quantity of electro-
chemical action be considerable, it is ignited ; so in the cata-
lytic combination, if the platinum be thin and of large extent,
or in the form of a sponge, which still more increases its sur-
face, it is ignited. Why, therefore, may we not regard the de-
tonation of gas by platinum as a voltaic effect? or the combina-
tion of oxygen and zinc by the presence of platinum a catalytic
effect? The only difference is, that gases do not admit of that
interchangeable relation of particles which we call electrolysis.
The necessity for this interchange is, however, removed when
the gases are in a state of such intimate admixture that it is
.not requisite to convey the action through a chain of particles ;
in the gas battery this chain is supplied by the intervening
electrolyte, and thus the same action which is local in the ex-
periments of Dobereiner is circulating in the gas battery ; the
latter bears the same relation to the former as the action of
the ordinary voltaic battery does to the normal phenomena
of chemical affinity. This relation is confirmed by the facts
detailed in the paper of Dr. Henry, as the gases which he
there found would combine by the presence of spongy plati-
num, are precisely those which will combine in the gas bat-
tery ; thus oxygen and hydrogen combine rapidly, oxygen and
carbonic oxide much more slowly, and oxygen and defiant
gas very feebly, so much so, as, in Henry's experiments, to
require heat to induce combination. Of course chlorine and
hydrogen, which will unite without platinum, will, a fortiori,
unite with the aid of platinum, or they may in the gas battery
occasion secondary action ; the oxygen evolved by the decom-
position of water by the chlorine combining with the free hy-
drogen in the tube. As oxygen and ammonia will, when at
a slightly elevated temperature, combine by the influence of
spongy platinum, forming water and leaving nitrogen, I now,
in order further to test this relation, tried

Experiment 26. — Ten cells of the gas battery were charged
with oxygen and solution of ammonia, with a little sulphate
of ammonia added to improve its conducting power. This
arrangement produced a moderate effect upon the iodide,

426 Mr. Grove on the Gas Voltaic Battery.

which was continuous ; the liquid rose slowly but uniformly in
the oxygen tubes ; a gas was evolved in the alternate tubes,
which proved to be pure nitrogen. After three weeks closed
circuit, the gases collected, measured, and averaged gave for
each tube,

Nitrogen evolved . . . = (V07 cubic inch.
Oxygen absorbed . . . =0*12
Experiment 27. — To examine whether the alkaline character
of ammonia had anything to do with the effect, ten cells were
charged with oxygen and solution of caustic potash, but pro-
duced no effect.

These experiments are strongly corroborative, and seem to
me conclusive as to the relation between the action of the gas
battery and catalysis by spongy platinum. Experiment 26 is
also remarkable in regard to the binary theory of electrolysis,
but upon this point I will not here enter.

Applying the hypothesis of Grotthus to the gas battery, we
may suppose that when the circuit is completed, at each point
of contact of oxygen, water and platinum, in the oxygen tube,
a molecule of hydrogen leaves its associated molecule of oxygen
to unite with one of the free gas; the oxygen thus thrown off
unites with the hydrogen of the adjoining molecule of water;
and so on until the last molecule of oxygen unites with a mole-
cule of the free hydrogen ; or we may conversely assume that
the action commences in the hydrogen tube. In all these
cases we should ever bear in mind that we proceed by steps
which nature, as hitherto tested by experiment, has not re-
cognised. All we can safely predicate of the actions at anode
and cathode is that they are correlations ; although they take
place at a distance, the one has no more been proved to take
place without the other, or before the other, than height has
been proved to exist without depth. I therefore allude to this
hypothesis, not as literally adhering to it, but because it is ge-
nerally received, and may tend to associate the action of the
gas battery with the ordinary phaenomena of electrolysis.

A number of hypotheses has been and may be proposed to
account for these and other mysterious phsenomenal relations ;
they all agree in being assimilations of what is unfamiliar to
what is familiar. They are undoubtedly useful as didactic il-
lustrations, and it is as such that they have hitherto contri-
buted to advance science. It is, however, a curious circum-
stance, and worthy of some consideration, that the voltaic hy-
pothesis of Grotthus, the emissive and undulatory hypotheses
of light and heat, and, as far as I am aware, all physical hy-
potheses hitherto propounded, represent natural agencies as
effects of motion and matter. These two seem the most di-

Mr. Grove on the Gas Voltaic Batter?/. 4*27

stinct, if not the only conceptions of the mind, with regard to
natural phaenomena, and when we try to comprehend or ex-
plain affections of matter which are not obviously modes of
motion, we hypothetically or theoretically reduce them to it:
the senses perceive the different effects of sound, light, heat,
electricity, &c, but the mind appears capable of distinctly
conceiving them only as modes of motion. Does not this
supply an argument that all physical agencies are reducible to
these elements of mental conception ? Or are we to look for
new powers of mind, in other words, will greater familiarity
with phaenomena, at present recondite, enable the mind more
clearly to comprehend them, and avoid the necessity of refer-
ring them theoretically to more familiar, and apparently more
simple phaenomena? To pursue this curious inquiry would
involve me in a discussion foreign to the object of this paper
and to the general character of contributions to the Royal
Society, but the question arises so immediately out of the sub-
ject, and is so necessary to explain my own view, that I trust
this brief statement of it will be considered sufficiently perti-
nent. It touches upon that interesting, scarce definable
boundary, where physical merges into metaphysical science.

There are one or two other theoretical points as to which
the gas battery offers ground of interesting speculation ; the
contact theory is one. If myfaotion of that theory be correct,
I am at a loss to know how the action of this battery will be
found consistent with it. If, indeed, the contact theory assume
contact as the efficient cause of voltaic action, but admit that
this can only be circulated by chemical action, I see little dif-
ference, save in the mere hypothetical expression, between the
contact and chemical theories; any conclusion which would
flow from the one would likewise bededucible from the other;
there is no sequence of time in the phaenomena, the contact or
completion of the circuit and the electrolytical action are syn-
chronous. If this be the view of contact theorists, the rival
theories are mere disputes about terms. If, however, the con-
tact theory connects with the term contact an idea of force
which does or may produce a voltaic current independently
of chemical action, a force without consumption, I cannot but
regard it as inconsistent with the whole tenor of voltaic facts
and general experience.

Another point of theory suggested by the gas battery, is the
relation of latent heat in the different cells of the battery and
voltameter. According to our received theory of caloric,
oxygen and hydrogen cannot assume the gaseous from the
liquid state without rendering sensible heat latent. Now, as
in the gas battery the gases evolved from the liquid in the

428 Mr. Grove on the Gas Voltaic Battery.

voltameter must require and absorb precisely as much heat as
is set free by the gases becoming liquid in each cell, it may be
a curious subject of future inquiry (an inquiry which that
beautiful instrument, the thermo-multiplier, will materially
aid) to ascertain whether the heat absorbed in the voltameter
be exacted from surrounding bodies, or whether it be supplied
by the action of the battery itself, i. e. as the chemical force
in the voltameter is conversely equivalent to that in each cell
of the battery, and the calorific force at the voltameter is also
the converse equivalent of that in each battery cell, whether
there is the same mutual dependence of the latter as of the
former forces. The action in the voltameter of ordinary bat-
teries would argue strongly against the proposition, that the
heat is exacted from surrounding bodies, as it is well known
that water when electrolysed has its temperature rather in-
creased than diminished; and I have found, when decompo-
sing water with the nitric acid battery at a rate of 150 cubic
inches a minute, a very considerable augmentation of tempe-
rature in the liquid subjected to decomposition, so much so,
that if the quantity was not considerable, it was heated to
ebullition. Much of this adventitious heat may have arisen
from the restriction of the circuit by the voltameter plates
and connecting wires, but if the gas battery be supposed to
supply exactly sufficient heat, or (to use a license of expres-
sion) to convert electricity into sufficient heat to satisfy the
demands of the expanding gases, — each battery cell being
able by the condensation of its respective gases to afford this
supply, — a rise of temperature ought to be perceptible in the
whole battery equal to the heat produced by the condensation
of gases in all the cells, minus that of one cell. I have not as
yet been able to detect any elevation of temperature due to the
action of the gas battery, not having in my possession any in-
strument capable of detecting such delicate thermoscopic
effects. I am, therefore, the more anxious to offer the point
for the consideration of those who may have such instruments
at their command ; and here for the present I leave the gas
battery and its theory.

London Institution, March 12, 1843.

Postscript, July 7th.

The length of time which has elapsed between the commu-
nication and printing of this paper, as it has enabled me to
procure the apparatus fig. 8, will I trust be deemed a sufficient
reason for my adding a Postscript containing a few experi-
ments with this form of battery, some of which I cannot but
consider important.

Mr. Grove on the Gas Voltaic Battery. 4-29

Experiment 28. — In order further to test the opinion ex-
pressed, p. 4-23, six cells of this battery were charged with
pure hydrogen and dilute acid in the alternate tubes. When
first charged they decomposed water freely ; but after the cir-
cuit had been closed for a short time, to exhaust the oxygen
of the atmospheric air in solution, they produced no voltaic
effect; the whole series of six would not decompose iodide of
potassium ; when, however, a little air was allowed to enter
any one of the tubes containing liquid, that single cell instantly
decomposed the iodide ; three cells were put aside, each in
closed circuit; at the expiration of a week these produced no
effect upon a galvanometer, nor was there any gas evolved in
the tubes containing liquid ; the stoppers were now taken out,
and the liquid in the hydrogen tubes rose to an average of 0*3
cubic inch ; each cell contained a pint, and we may therefore
regard 0*15 cubic inch as the amount of oxygen held in so-
lution by this quantity of acidulated water. Were it not for
the extreme practical difficultyof perfectly excluding atmo-
spheric air for a long period, the above would furnish an ex-
cellent method of examining the quantity of oxygen held in
solution by water, and by applying the proper calculus we
might read off on our galvanometer scale the infinitesimal
bubbles of gas contained in a given bulk of liquid ; if, how-
ever, the acid water or the hydrogen contain foreign ingre-
dients, a very different result follows, and the liquid, for rea-
sons which will now be obvious, frequently rises considerably
in the hydrogen tubes.

Experiment 29. — I repeated experiment 24 with the battery
fig. 8, expecting that as the external air was shut out I should
obtain the result more speedily ; I was indeed not without a
vague hope of producing some effect upon the nitrogen. The
first result did follow ; upon taking out the stoppers the morn-
ing after the battery had been charged, the liquid rose in the
air-tube one-fifth of the gaseous volume. I now closed it
again and examined it three days afterwards j a very curious
effect had taken place ; the volume of the gas in the air-tube
which had previously contracted had now increased, and it
continued slowly increasing day after day. I at first believed
that the nitrogen was decomposed, but after many conjectures
and experiments found that the increase was due to the addi-
tion of hydrogen, a fact to me more extraordinary than the
decomposition of nitrogen would have been. On repeating
the experiment with nitrogen instead of air the same effect
took place, but of course without the previous contraction. I
now returned to battery fig. 4 ; several of these cells charged,
some with atmospheric air and hydrogen, and others with ni-

430 Mr. Grove on the Gas Voltaic Battery.

trogen and hydrogen, did not exhibit the effect, thougli suf-
fered to remain six weeks, each in closed circuit.

To ascertain whether the vacuum formed by the abstrac-
tion of oxygen from the liquid had anything to do with the
above effect, a central narrow tube, open at both ends, was
substituted for the stopper in the battery fig. 8 ; the hydrogen
was still evolved. Not to detail a tedious set of test experi-
ments, I at length found that two points were essential to ob-
taining the effect with certainty; first, the exclusion of any
notable quantity of atmospheric air from solution; and se-
condly, great purity in the hydrogen. In the former case,
when the hydrogen could find oxygen to combine with, it was
not evolved ; in the latter, there would be mixed or rather di-
luted gas on both sides, and the forces would be balanced ;
thus 1 have never succeeded in obtaining the effect in the open
battery, fig. 4, with hydrogen obtained in the ordinary way
from granulated zinc or iron filings, but have sometimes suc-
ceeded with hydrogen procured by electrolysis. In the bat-
tery fig. 8, I have succeeded in producing the effect, but in a
feeble degree, from hydrogen obtained in the common way,
but have never failed with hydrogen obtained by electrolysis.
Oxygen of the greatest purity, voltaically associated with ni-
trogen, does not produce a similar effect. The above unex-
pected results render it necessary, in order to ensure accuracy
in the eudiometric experiment 24, either purposely to use
common hydrogen in the batteries figs. 4 and 12, or, what
is more expeditious and accurate, to use a battery similar to
fig. 8, but with tubes longer in proportion to their width ; and
having first charged the tubes with hydrogen and atmospheric
air, to allow these to remain in closed circuit until all the
oxygen is abstracted and a little hydrogen added, by the elec-
trolytic effect, to the residual nitrogen; then to substitute
oxygen for the original hydrogen, which will in its turn abs-
tract the hydrogen from the nitrogen and leave only pure ni-
trogen. I have frequently done this with perfect success.

Experiment 30. — Hydrogen and carbonic acid in battery
fig. 8 produced the same effect. The volume of the carbonic
acid was increased, and hydrogen was found to have been
added to it. The effect therefore is not due to any peculi-
arity of nitrogen, but yet some gas is necessary, for experi-
ment 28 proves that hydrogen alone will not decompose water.
I need scarcely say, that when the above-mentioned effect took
place an interposed galvanometer was deflected, but the cur-
rent was much too feeble to decompose iodide of potassium.

I have tried, associated with hydrogen in battery fig. 8,
carbonic oxide, defiant gas, protoxide of nitrogen, and deut-

Mr. Grove on the Gas Voltaic Battery. 431

oxide of nitrogen ; the two former produced no current or
chemical effect, the two latter gave a current and were decom-
posed. The volume of the deutoxide contracted one-half,
this was found to be nitrogen, which thenceforth was gradually
increased by hydrogen. The volume of the protoxide did
not undergo the previous contraction, except slightly from
solubility, but its change of state was denoted by the absorp-
tion of hydrogen in the associated tube.

I likewise tried the effect of a vacuum and hydrogen, by
charging a battery (fig. 8) with 1 cubic inch oxygen and 3
cubic inches hydrogen; the current was much enfeebled by
the resistance offered by the vacuum, at first iodide of potas-
sium was decomposed and the galvanometer needle whirled
round. After twenty-four hours the galvanometer needle was
only deflected 10°, thus a physical was opposed to, and re-
sisted, a chemical force; the current however continued, and
all the gas in the oxygen tube disappeared, except a minute
bubble ; this was probably nitrogen from the atmospheric air
in solution, which had escaped to fill the vacuum. When the
stopper was taken out the liquid rose suddenly in the hydrogen
tube 2*2 cubic inches, giving the equivalent of the oxygen in
the tube and in solution. It is very possible that this ex-
periment repeated might sometimes exhibit an evolution of
hydrogen in the oxygen tube arising from the escape of the
nitrogen of the atmospheric air in solution, and acting as in
experiment 29, but I have not seen this effect take place. It
should be distinctly understood, that in all the experiments
mentioned in this Postscript, except the first part of experi-
ment 28, single cells only were used.

Upon the theory of the experiments 29 and 30 I will ven-
ture no positive opinion. That gaseous hydrogen should
abstract oxygen from hydrogen, without the latter forming any
other combination, is a fact so novel, that any attempted ex-
planation is likely to prove premature. If, contrary to the
views of Dalton, we suppose that gases when mixed are held
together by a feeble chemical affinity, then we may say that
the affinity of the nitrogen or carbonic acid for hydrogen pro-
duces the effect ; the affinity of the oxygen of the water, being
balanced between the hydrogen in the liquid and that in the
tube, would enable the resultant feeble affinity of the nitrogen
for hydrogen to prevail ; but on this supposition, why does
not oxygen produce an analogous effect? Its tendency di-
rectly to combine with platinum may indeed be regarded as
an opposing force, but this tendency is by many considered
hypothetical. On the other hand, it may be called an effect
of contact; but this, unconnected with a chemical theory,

432 The Rev. J. A. Coombe on the form of

presents no other idea to the mind than the fact itself presents,
it furnishes no link by which we may extend the phsenomena.
I therefore, until a better theory be found, should be inclined
to adopt the former view, and to regard mixed gas as in a
state of feeble chemical union, the more especially as through-
out nature we find no absolute lines of demarcation, though
for conventional reasons we are obliged to adopt them ; there
must be many cases in which it is difficult, if not impossible,
to draw the line between mechanical mixture and chemical
combination.

In conclusion, I would say with regard to the whole of the
experiments contained in this paper, that a longer time and
more experience may give positive results in cases where I
have only obtained negative ones; it is far from impossible
that since curious solid combinations are formed by slow elec-
trical currents, as in the experiments of Crosse and Becquerel,
so novel gaseous or liquid products may be obtained by the
long-continued voltaic action of gases and liquids. This time
alone can show.

For previous experiments and theories on the combination
of gases by platinum, I may refer to Dobereiner's paper, Phil.
Mag. Oct. 1823, in which I find he expresses an opinion that
it is a voltaic effect; to the papers of Dulong and Thenard,
Annates de Chimie, torn. 23 and 24 ; and to Faraday's Expe-
rimental Researches, Series 6. The various experiments on
polarized electrodes of Ritter, Faraday, De la Rive, Becquerel,
Matteucci, and Schcenbein, are also in point.

LXII. On the Form of Equilibrium of an Inextensible String
laid on a surface and acted on by any forces. By the Rev.
J. A. Coombe, M.A., Fellow of St. John's College, Cam-
bridge *.

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

THE following method of investigating the form of equi-
librium of an inextensible string laid on a surface and
acted on by any forces, has the advantage of presenting a re-
sult extremely neat and symmetrical. I adhere to the suffix
notation in expressing a differential coefficient, never having
yet seen any arguments, of much value, brought against this
elegant and convenient method.

Let u = 0 be the equation to the surface.
xy z the rectangular coordinates of any point of the string,
and therefore of a point in the surface.

* Communicated by the Author.

Equilibrium of an Inextensible String. 433

s the length of a portion of the string intercepted between a
fixed point in the string and the point (xyz).

Y [the resolved parts of the forces at the point {xyz) J
2 | parallel to Trj

R the normal reaction, making angles « /3 y with the axes.

Then T being the tension of the string at one extremity of
the element 85, T dgx will be the resolved part in x, and Tdgx
+ ds (T dsx)$s will be the resolved part in x of the tension at
the other extremity. Hence d (Td x)$s will be the differ-
ence of the resolved parts in x.

The other forces acting on Is parallel to x are X8s and
R Is cos a. : hence by the equations of equilibrium, supposing
85 to be a rigid substance, we have (dividing by Is)

ds(Tdsx) + X + Rcosa = 0. . . . (1.)

So da{Tdsy) + Y + Rcos/3 = 0, . . . (2.)

ds{Tdsz) +Z + Rcosy = 0; . . . (3.)

and we have to eliminate T and R between these equations.

Now (1.) dsx+ (2.) dsy + (3.) dgz = 0, gives

dT{(dsx)* + (d,y)* + (dszy} + T{dsxd?x + dsyds*y+dszds*z}

+ Xdsx + Ydsy+Zdsz

+ R {cos u dsx + cos fidsy + cosy d8z} = 0.

Now {dsxf + {dsyf + {dszf = 1 ;

.:dsxd*x+dsyd*y + dszd*z = 0.

Also, since the tangent to the curve is perpendicular to the
normal to the surface, we have

cos a ds x + cos /3 dsy + cos y ds z = 0.
Hence the above equation becomes

dsT + Xdsx + Y dsy + Zdsz = 0;
or if X dsx + Y dsy + Zdsz = dsv,

T + w = 0, . (4.)

supposing the arbitrary constant included in v.
Again, (1.) dsy — (2.) dsx = 0 gives

T {dsy ds* x-dsx d*y) + Xdsy-Ydtx
+ R (cos u dsy — cos fidsx) — 0.
Now if V = {(d,uf + (dyuf + (dxu?}-\

cos « = V d» n cos (& = V dy w cos 7 = V & w,
the differential coefficients being partial.
Phil. Mag. S. 3. Vol. 24. No. 161. June 1844. 2 F

434< The Rev. J. A. Coombe on an Inextensible String.

Hence we have

T (ds y d* x — ds x ds2y) + X ds y — Y ds x~\ . .

+ RV(ia dsy — dy u ds x) = 0. J '

So T (ds xds2z — ds zd?x) + Z ds x — X d, z~\ . .

+ RV(dzudsx — dxudsz) = 0, J ' ' * *'

and T{dszd?y — dsyds*z) + Ydsz — Zday\ .

4* RV(<^«<&» — dziidsy) *&0, J ' ' ^ '

Hence (5.) rf,« + (6.)^w + (7.) dxu — 0 gives, on sub-
stituting for T its value derived from (4.),

vdzu(dsyd9x — dsxd9y) dzu(Ydsx — Xdsy)^
+ vdyu{d'sxds*z — dszd/?x) = + dyu(Xdsz — Zdsx) I (A.)
+ vdxu(dszds*y — dsyd?z) -\-dxu(Zdsy — Y dsz)J

This equation, together with u = 0, are the equations to the
curve of double curvature into which the string is arranged.
II. To find the pressure on the surface at any point,
0 = (1 .) cos « + (2.) cos /3 + (3.) cos y,
gives — R = X cos a + Y cos /3 + Z cos 7

+ T {ds* x cos a + d*y cos /3 + d,9 z cos y } .
Now if p be the radius of absolute curvature at the point
(xy z) and A, //,, v the angles it makes with the axes, we have
cos \ = pd/x cos fi = p ds2y cos v ■=. pd9 2,

.♦. — RSs = X8s.cosa + Y8s. cos/3 + ZSs.cosy
■ T-K

H {COSaCOSX -j- COS/3cOS/4 + COSyCOSv}.

Now let 9 be the angle between the radius of absolute cur-
vature, in which direction the resultant of the tensions on the
extremities of Is acts, and the normal to the surface, then

cos 0 = cosacosA + cos/3cos/a + cosycosv.
Then pressure on the portion 8 s of the surface
= resolved force in the normal,

+ resolved tension

III. There is one particular case which deserves especial
notice, from the peculiar character of the result. It is when
the resultant K of the forces X, Y, Z acts in the normal to the
surface at the point (xy z), so that

X = RVrf,KY = KV^«Z = KVrf,B,
in which case the equation (A.) becomes

dzu{dsyd^x—dsxd^y) dzu(dpudsx—dxudsy)KV "j
+ dyii(dsxds'2z—dszdJix)==+d2/u(dxudsz—dzudsx)KV I (8.)
+ dxu(dsz d?y — dsyds2 z) + dxu {dziidsy — dyudsz) K V = 0 J
or substituting A, B, C for the coefficients of dtVu, dyii, dzu,
the equation is

Mr. Robert Hunt on Chromo-Cy allotype. 435

A dx u 4- Bdvu + C dz u = 0.
Now the equation to the osculating plane at the point (xyz) is

A(X-*) + B(Y-ijO+C(Z-*)s=0; . . (9.)
and the equations to the normal are

(10.)

d„ u dyu dz u

X-x~Y-y Z-z' ' *
X, Y, Z being the current coordinates of a point in the plane
or normal; and when the plane (9.) contains the normal (10.),
we have the condition

A d0 u + BdgU +- C dz u = 0.
Hence equation (8.) expresses that the osculating plane con-
tains the normal ; now this is the property of the shortest line
between two points on the surface. Also we have
ds T = — (Xdsx + Ydsy + Z ds z) = 0,
.*. T = constant = /<•,

k
and pressure = — on an unit of length.

Since the tension is constant, we must suppose the two ex-
tremities either to be fastened to the surface or pulled by any
equal forces; and then the curve into which the string will be
arranged will coincide with the shortest line that can be drawn
on the surface between those points.

I remain, Gentlemen,
St. John's College, Cambridge, Your obedient Servant,

March 25, 1844. J. A. CoOMBE.

LXIII. Chromo-Cyanotype, a neiv Photographic Process. By
Robert Hunt, Secretary to the Royal Cornwall Poly-
technic Society.

To Richard Taylor, Esq.
Dear Sir,
EING engaged in the investigation of some changes pro-
duced by the agency of the solar rays upon various me-
tallic solutions, I was led to notice some very remarkable
effects connected with the precipitation of the per- and proto-
salts of iron. It would be premature to publish these expe-
riments, but there has arisen out of them a photographic pro-
cess of so pleasing a character, affording phaenomena of so
curious a nature, and the process is so exceedingly simple,
that I am induced to forward a description of it to you, not
doubting but it will be interesting to the readers of the Philo-
sophical Magazine.

To distinguish this from the cyanotype processes of Sir

2 F2

B

436 Mr. Robert Hunt on Chromo-Cyanotype^

John Herschel, which in many respects it resembles, I pro-
pose to call it chromo-cyanotype, the propriety of which
term will, from the following description of the process, be
sufficiently apparent.

It is now well known that the bichromate of potash is very
susceptible of change under the influence of the chemical
principle of the solar rays, which, for reasons I have elsewhere
assigned*, I am disposed to consider as an independent prin-
ciple, and for which I have suggested the name Energia. At
the last meeting of the British Association, I published a pro-
cess (the chromatype) in which a mixture of the bichromate
of potash and the sulphate of copper was the photographic
material employed. In the process to which I would now call
attention, the bichromate is used in combination with the fer-
rocyanate of potash. I draw attention to this, more particu-
larly, to show how very varied are the photographic effects
produced by the combinations of chromic acid ; in addition to
those already published, my experience has brought me ac-
quainted with at least twenty others, which promise, with at-
tentive manipulation, to produce singularly varied and beauti-
ful results.

To one ounce of a saturated solution of the bichromate of
potash add half an ounce of a solution of the ferrocyanate of
potash containing half a drachm of the salt. The solutions
upon mixing become a dark brown, but no precipitation takes
place. With this mixture wash over one side of a sheet of
letter paper and dry it by the fire. Upon paper thus pre-
pared a picture is impressed in the ordinary way, the image
being a very faint negative one. This paper is not sufficiently
sensitive to be affected by the subdued light of the camera
obscura, but in the sunshine very interesting copies of engra-
vings may be procured. Upon this paper, as upon the com-
bination of the bichromate of potash and the sulphate of copper
used in the chromatype process, the sun's rays exert two di-
stinct actions, browning the paper in the first instance, and
then with some rapidity bleaching it. Prismatic analysis
shows these two dissimilar effects to be produced by rays of
nearly the same degree of refrangibility. The first browning
takes place under the mean blue ray of the spectrum, and
gradually extends itself upwards to beyond the violet ray, and
downwards to the green ray ; and the first indication of whi-
tening is seen about the mean violet, and it extends slowly
over the whole of that space which has been previously dark-
ened. We have several curious instances in which rays are
seen to destroy their own work in this manner.
* See Researches on Light, by the author.

a new Photographic Process. 437

The very faint negative picture, produced as above, will, if
plunged into a weak solution of the sulphate of the protoxide
of iron, be immediately changed into a positive one; the
shadows being formed by a deposit of prussian blue, more
copiously over those parts which were shaded than those on
which the sun had more influence. The picture thus formed
is however somewhat indistinct, but by looking through the
paper it is seen that every part is faithfully preserved. If in-
stead of the proto-salt the persulphate is used, a very intense
blue negative picture of considerable interest results. In this
case the deposit of prussian blue takes place over the solarized
portions of the paper, the precipitation being relatively ac-
cording to the quantity of " energia " which has acted upon
the preparation. The lighter parts of these photographs are
at first yellow, and if left in this state they are liable to be-
come blue; but if soaked for a few minutes in a solution of
carbonate of soda, the yellow colour is removed, and the pic-
ture is a white and an intense blue. These drawings, as you
will perceive from the specimens sent, will not serve as origi-
nals from which copies might be taken, they do not possess
transparency. It is curious, however, to mark the develop-
ment of a positive image on the back of each negative picture,
which, though faint, has much the air of a mezzotinto engra-
ving.

The different action of the two sulphates of iron is remark-
able, and it hardly admits of a satisfactory explanation. It
would appear that the ferrocyanate of potash, spread upon
paper, undergoes some change which prevents its precipitating
the proto-sulphate, by long exposure to sunshine ; but with
this salt alone I have never, in this way, been enabled to get
more than an image of the body obscuring the paper ; I there-
fore regard the bichromate of potash as accelerating merely
the change on the ferrocyanate. Papers spread with the fer-
rocyanate alone are affected precisely in the same manner if
plunged into a solution of the sulphate of the peroxide. In
both cases with the chromo-cyanotypes, the unchanged parts
of the picture precipitate prussian blue, and hence we have in
the one case a positive picture on the right side of the paper,
and in the other case a positive image on the wrong side of
the paper. I find, upon dipping a photographic picture
formed on paper, simply spread with the bichromate of potash,
into the per-solution, that every part is immediately removed,
and the paper left perfectly white. From this it would appear
that the oxide of chromium formed over the most exposed
parts is dissolved off, leaving the ferrocyanate of potash to
exert its influence on the salt of iron, which it does with greater

438 Mr. Robert Hunt on Chromo-Cyanotype.

energy than upon those parts on which the mixed salts of
chrome and ferrocyanogen remain unchanged.

In subjecting paper thus prepared to prismatic analysis, the
space covered by the blue ray is the first which darkens, and
for some time the action is confined to this portion of the
spectrum ; but it extends at length, as before stated, from the
most refrangible limits of the green ray to a space a little be-
yond the visible violet rays. If, however, after a short expo-
sure to the spectrum, the paper is dipped into a solution of the
protosulphate of iron, a space which corresponds in extent to
the entire luminous spectrum is left free, or nearly so, of preci-
pitated prussian blue. If after an exposure of fifteen or twenty
minutes to the prismatic image, concentrated by means of a
lens, we wash the paper, without removing it, with the iron
salt, the precipitation appears to take place pretty uniformly
over every part ; but if we soak it in a little water, and then
wash the paper with a soft sponge, all the prussian blue is re-
moved, except over a space which exceeds the limits of the
visible spectrum at both ends. Below the visible red rays the
action appears to have extended to the maximum heat spot,
so well developed in the experiments of Sir John Herschel,
the blue deposit forming a well-defined circular termination,
below which are some evidences of a protecting action similar
to that exerted by the " extreme red rays " in many instances.
Beyond the violet rays the action is extended over the invi-
sible space to an extent nearly equal to that of the so-called
"visible chemical rays." The action is tolerably uniform
throughout the whole extent of this spectrum, but there are
evidences of a maximum action in the mean blue ray. I en-
close you the spectral image thus formed.

If we soak one of these negative chromo-cyanotypes in a
solution of pure potash or ammonia, the picture is obliterated,
but it may be revived by exposure to sunshine, or by the ap-
plication of heat; but in both cases the parts which were blue
become brown.

The picture is still more perfectly obliterated if we expose
it to the action of the nitrate of mercury and sunshine at the
same time ; a sheet of blank white paper apparently remains,
but the picture is only clouded, not destroyed. If held before
a warm fire, or still better, if a hot iron is applied, a positive
image of some intensity replaces the negative one. This pe-
culiarity has been noticed in the cyanotypes by Sir John
Herschel, but in the instances he has given the picture is im-
proved by washing out the mercurial salt previously to the ap-
plication of heat, but if this is done in the present instance, the
revived picture is exceedingly faint. Such are the interesting

Sir D. Brewster on the Law of Position in Vision. 439

peculiarities of this preparation ; and they furnish us with ad-
ditional evidence of the remarkable changes induced in bodies
by the solar emanations, which we were comparatively igno-
rant of previously to the publication of the Daguerreotype and
photographic processes.

I remain, dear Sir,

Yours faithfully,
Falmouth, May 8, 1844. Robert Hunt.

LXIV. On the Law of Visible Position in Single and Bi-
nocular Vision, and on the representation of Solid Figures
by the union of dissimilar Plane Pictures on the Retina. By
Sir David Brewster, K.H.,D.C.L., F.R.S., and V.P.R.S.
Edin.

[Continued from p. 365 and concluded.]

4. On the Binocular Vision of Figures of Different Magnitudes.
iyt R. WHEATSTONE seems to have been the first person
■*"-*■ who made experiments on the binocular vision of un-
equal figures. Having drawn on separate pieces of paper "two
squares or circles, differing obviously, but not extravagantly, in
size," he placed them in the stereoscope, and concluded from
his observations that the two unequal •pictures "coalesced, and
occasioned asingleresultant perception;" and that thebinocular
image thus perceived was apparently intermediate in size be-
tween the two unequal monocular ones. This perfect coa-
lescence of the two images he considers as demonstrated, and
he deduces from it the important conclusion, that, if it were
otherwise, " objects would appear single only when the optic
axes converge immediately forwards." That is, we see objects
single when the optic axes converge laterally in virtue of the
coincidence of two unequal images.

These extraordinary results are obviously subversive of the
established laws of vision, but especially of the law of visible
direction ; and if they are true, they must arise from a sudden
change in the properties of the humours, or in the functions
of the retina. The lesser image may become greater, or the
greater less, by a variation in the refractive density or the
form of the cornea and the crystalline lens, or, what would be
more probable, the retina may become subject to a new law
of visible direction. Assuming this to be the case, we must
suppose the change of law to take place in each eye, so that
the larger image must be seen less, and the smaller image seen
greater, than they really are. Now, this change must take
place instantaneously at the moment of coalescence, for the
two images retain their proper magnitude till their apparent

440 Sir David Brewster on the Law of Visible Position

union takes place; and the eye must recover its ordinary
functions as instantaneously, for the moment we intercept one
of the images the other resumes its proper size.

In order to understand what the nature of this supposed
change actually is, let MN, M'N' (fig. 3, 4) be the two eyes,

Fig. 3. Fig. 4.

A B the larger image, and a b the smaller one ; then if C be
the centre of curvature of the retina, the points A, B will be
seen in the directions An, Bm intersecting at C, and the
points a, b in the directions as, br intersecting at C But
when these separate images coalesce, in consequence of A B
becoming less and b c greater, the points A, B, a, b must be
seen in the directions A n, B o, a v, b t, intersecting at new
centres of visible direction c, d, the one further from, and the
other nearer to, the retina. If we now shift the larger picture
to the right eye, and the smaller to the left eye, the function
of the retina will be again changed : the left eye M N will
have its lines of visible direction as in fig. 4, and the right eye
as in fig. 3. Such an oscillation of the binocular centre of
visible direction on each side of the monocular centre, produced
solely during the attempt to unite unequal images, would in-
dicate a function of the retina so extraordinary, that the most
incontrovertible experiments, and the universal experience of
accurate observers, could alone give it credibility.

There is no doubt that the two unequal images appear to
coalesce; but if we make the outlines of the squares and
circles luminous, by pricking small holes in their outlines, and
exposing them to very strong light, we shall find it impossible
to produce a coincidence. The best way to make this expe-
riment is to take two lines, A B, a b, fig. 5, of unequal lengths,
and with a large pin to perforate the lines at A, B, a, b, so that
when we attempt to unite them, as at fig. 6, we shall see with
perfect distinctness their four luminous extremities. When

in Single and Binocular Vision. 441

the point a is made to pass into A, I have never succeeded in
making b pass into B. Whenever there is an appearance of
this, either turn round the paper, or the head, so as to sepa-
rate the lines as in fig. 6, and it will be invariably seen that if

Fig. 5. Fig. 6.
A B a b A! B'

y

a springs out of A, ftwill spring out of a point between A and
B. The apparent coincidence, therefore, of A B with a b,
fig. 6, when it is seen, arises from the disappearance of one or
other of the extremities of the two lines.

But Mr. Wheatstone has described another very interesting
experiment, of the same character as that which we have been
examining, and he regards it as "proving that similar pictures,
falling on corresponding points of the two retinae, may appear
double and in different places." Draw a strong vertical line,
A B, fig. 7, and another C D inclined some
degrees to it, and also a faint line m n parallel Q
to A B, and cutting C D at its centre S, then,
according to Mr. Wheatstone, the two strong
lines A B, CD, when seen with different eyes
in the stereoscope, or brought together by
looking at a nearer object, " will coincide, and
the resultant perspective line (CD) will appear
to occupy the same place as before ; but the
faint line (m n) which now falls on a line of the
left retina, which corresponds with the line of
the right retina, on which one of the coinciding
strong lines, viz. the vertical one (A B) falls,
appears in a different place." In repeating
this experiment, I have occasionally observed
an apparent coincidence similar to that which is described in
the preceding passage; but after numerous and varied obser-
vations, made with lines coloured and uncoloured, opake and
transparent, similar and dissimilar both in strength and form,
I have no hesitation in affirming that the pha?nomenon de-
scribed by Mr. Wheatstone is an illusion, arising from the
actual disappearance of one or more parts, or even of the whole
of one of the lines, and from the difficulty of observing the
separation or superposition of images in the circumstances
under which the experiment is made.

The following are a few of the variations of the experiment
which I have found the best calculated to exhibit the real
place of the combined images.

1. In Mr. Wheatstone's form of the lines shown in fig. 7,
the strong line A B assumes more readily the appearance of

442 Sir David Brewster on the Law of Visible Position

uniting with the similarly strong line C D ; but if m n is a
strong line and C D a weak one (fig. 1 1), or an interrupted one,
AB will unite with mn, and not even apparently with CD.
In like manner, if A B be a weak line, it will unite with the
weak line mn rather than with C D. (See fig. 12.)

Now, the apparent coalescence of similar lines arises from
the fact, that when corresponding, or nearly corresponding,
parts of the retinae are impressed with similar images, one of
the two more readily vanishes, independent of its liability to
vanish from its being out of the axis of vision. Whenever
two images interfere with one another so as to impede vision,
one of them disappears — or rather, is not taken cognisance of
by the eye. Hence it is that many sportsmen shoot with
both eyes open ; and hence it is that, in very oblique vision,
one of the eyes resigns its office, and leaves the other to view
the object distinctly and singly *.

But, in point of fact, A B, fig. 7, does not coalesce with
C D. If the eye strives to see distinctly any object at the
point S', then A B coalesces with m n. If the eye looks fix-
edly at C when A is united with C, A S' will unite with C S'
and S' B with S' n ; and if the eye is fixed intently on D when
B and D are united, S' B will coalesce with S' D and A S with
m S'. In these last two cases, the coalescence arises from the
same cause as the coalescence of dissimilar forms in Mr.
Wheatstone's fundamental experiment, as I shall now show.

2. If we join Cm, Dw, fig. 7 (as is done in fig. 8), we may
regard A B and CmS'»D as dissimilar images of a solid,
consisting of two triangles C m S', D n S', united at their apex.
In this case, A S, fig. 8, will coincide with C S' and S' B with
Sn. If the two dissimilar images are, as in figs. 9, 10, 11,
and 12, A B will not appear to coalesce with C D. In fig. 13
the coalescence is not complete ; but it becomes so by removing
the portion a b of the line A B, the part A a coalescing with
C, and b B with D. In fig. 14, the line A B will not coalesce
with C D : but each separate portion of A B will, when the
other two portions are concealed or removed, coalesce with
the corresponding portion of C D.

The ocular equivocation, as it may be called, which is pro-
duced by the capricious disappearance and I'eappearance of
images formed on nearly corresponding parts of the retina of
each eye, is placed beyond a doubt by Mr. Wheatstone's own
experiments f. Having inscribed the letters A, S, fig. 15, in
two equal circles, he unites the circles, and finds, that, while

* The fact of objects seen obliquely not being double, is ascribed by Mr.
Wheatstone to the coalescence of the images of different magnitudes given
by each eye.

f Philosophical Transactions, 1838, p. 386, § 14.

in Single and Binocular Vision. 443

Fig. 8. Fig. 9. Fig. 10.

C m A C AC A

n D B

Fig. 11.
C m A

D B

Fig. 12.
Cm A

Fig. 13.
C 8 A

D B
Fig. 14.

D B D B

1

Fig. 15.

© ®

D B

444 Sir David Brewster on the Law of Visible Position

the common border remains constant, "the letter within it
will change alternately " from A to S. At the instant of
change the letter " breaks into fragments ; while fragments of
the letter which is about to appear, mingle with them, and are
immediately replaced by the entire letter." I have long ago*
described an affection of the retina, of an analogous kind,
which illustrates the subject under consideration. " If we
look very steadily and continuously with both eyes at a double
pattern — such as one of those on a carpet — composed of two
single patterns of different colours, suppose red and green ;
and if we direct the mind particularly to the contemplation of
the red one, the green pattern will sometimes vanish entirely,
leaving the red one alone visible; and, by the same process,
the red one may be made to disappear." When we join to
these various facts the remarkable phenomena of the disap-
pearance of objects seen out of the axis of vision by one or
by both eyesf, we shall find it difficult to believe that two si-
milar unequal figures can coalesce ; or that " similar pictures,
falling upon corresponding points of the two retinas, may ap-
pear double and in different places."

5. On the Cause of the Perception of Objects in Relief by the
Coalescence of Dissimilar Pictures.
Mr. Wheatstone concludes his interesting paper with an
inquiry into the cause "why two dissimilar pictures, projected
on the two retinae, give rise to the perception of an object in
relief." " I will not attempt," he adds, " at present, to give the
complete solution of this question, which is far from being so
easy as at a first glance it may appear to be, and is, indeed,
one of great complexity. I shall, in this place, merely con-
sider the most obvious explanations which might be offered,
and show their insufficiency to explain the whole of the phae-
nomena."

Mr. Wheatstone then proceeds to describe the process of
vision in the same manner as we have done in § 3 ; but im-
pressed with the conviction that his previous results are cor-
rect, he adds, " All this is in some degree true', but were it en-
tirely so, no appearance of relief should present itself when the
eyes remain intently fixed on one point of a binocular image
in the stereoscope." He then gives the following experiment
as decisive on the subject: — "Draw two lines, about two
inches long, and inclined towards each other as in fig. 7, on
a sheet of paper ; and having caused them to coincide by con-
verging the optic axes to a point nearer than the paper, look
intently on the upper end of the resultant line without allow-
* Letters on Natural Magic, p. 54. f Ibid., Let. III., p. 54.

in Single and Binocular Vision. 445

'£>

ing the eyes to wander from it for a moment. The entire line
will appear single, and in its proper relief," &c. After making
this experiment with the greatest care, we admit that it may
appear single, without being single. To us it does not appear
single, but exactly the same as a line having the same length
and the same position appears in ordinary vision. Now,
though this latter line appears single to most eyes, yet it is
certain that every point of it is double and indistinct, except-
ing the point on which the attention is fixed, and to which
the optic axes converge. The vision of objects in relief from
the union of dissimilar pictures, is performed by the very same
process as the vision of real objects in relief by the ordinary
agency of our two eyes ; and in establishing this principle, the
true cause of the phaenomenon discovered by Mr. Wheatstone
will be readily obtained.

Mr. Wheatstone considers it as experimentally established,
that " the most vivid belief of the solidity of an object of three
dimensions arises from two different perspective projections of
it being simultaneously presented to the mind ;" and that "the
simultaneous vision of two dissimilar pictures suggests the re-
lief of objects in the most vivid manner." Having already
explained, in § 3, the true process by which solid bodies are
seen in relief, I shall now endeavour to show, that, in the vivid
relief produced by the union of two dissimilar plane pictures,
this union is merely a necessary accessory, and not the cause
of the phfenomenon in question.

When two of the images of two perfectly similar objects are
united either by looking at a nearer or a remote object, the
compound image thus formed is seen at the place where the
two optic axes converge, and is larger and more remote than
the single image if we look at a more distant object, and
smaller and nearer if we look at a nearer object*. The best
mode of conducting this class of experiments is to suspend two
equal rings by invisible fibres, or to cement them upon a large
plate of glass, whose surface and figure are not visible to the
observer. The object of this arrangement is to prevent the
observer from having any knowledge of their distance from
the eye. When the rings, thus placed, are doubled, interpose
an aperture, so as to permit only the united rings to be seen ;
and it will be found that they appear at the place to which the
optic axes converge, appearing smaller and nearer, or larger
and more remote, according as the optic axes are converged
to a point nearer or more distant than the actual rings. In

* Several curious facts establishing this result have been given by Dr.
Smith in his Complete System of Optics, vol. ii. 387-389; and Remarks,
§ 526-527-

446 Sir David Brewster on the Law of Visible Position

both these cases, the similar rings are seen in identically the
same manner, having the same apparent magnitude and posi-
tion as if a similar real ring were placed as an object at the
spot to which the optic axes converge. Let us now apply these
facts to the vision of the apparent solid produced in conse-
quence of the union of two dissimilar plane pictures of it. For
this purpose, I shall take the case of the frustum of a cone,
after having considered the process by which we see a real
frustum of a cone by both eyes — the nature of the compound
picture which we do see — and the cause of the apparent single
picture of which the mind takes cognizance.

When we look at the real frustum of a cone (A B C D,
placed as in fig. 16), the right eye R sees a solid, whose pro-
jection is a! b' C D, or a b c d, fig. 1 7 ; and the left eye a solid,
whose projection is A'B'CD, or ABC D, fig. 17. The
smaller circle C D appears nearer to the observer than the
base A B, because the eye cannot see it distinctly without ad-
justing itself to the distance R C, L D, and converging its
optic axes to that distance. Each eye, acting alone, sees the
cone single, and the various points of its outline are seen more
or less distinct, according as they are more or less remote from
the point to which the eye is for the instant adjusted. But so
rapid is the motion of the eye, and so quickly does it survey
the whole of the solid, that it obtains a most distinct percep-
tion of its form, its surface, and its solidity. When we view
the cone with both eyes, we have the same indistinctness of
outline when the optic axes are converged to a single point :
but in addition to this, we have the greater indistinctness ari-
sing from every point of the figure being seen double, except
the single point to which the axes are converged. But this
imperfection, too, is scarcely visible, from the rapid view which
the eyes take of the whole solid, converging their axes upon
every point of it, and thus seeing each point in succession
single and distinct. Hence we must draw a marked distinc-
tion between the vision of the solid (as an optical fact) when
the eyes are fixed upon one point of it, and the resultant per-
ception of its figure arising from the union of all the separate
sensations received by the two eyes.

Let ABCD, fig. 16, be the solid frustum of a cone, having
its axis M N produced, bisecting at O the distance L R be-
tween the two eyes L, R. Draw A L, A R, B L, B R ; and
also CL, CR, and DL, DR. Then, if we look at this solid
with the left eye L only, the projection of it will be as shown
in fig. 17 at ABCD, and in fig. 16 at A'B'CD; AC being
much greater than DB, and the summit-plane CD appearing
on the right-hand side of the centre of the base AB. The

in Single and Binocular Vision.

447

reason of this is obvious from fig. 16, where the left eye L sees
the side A C under the angle A L C, while it sees the other

Fig. 17.

448 Sir David Brewster on the Law of Visible Position

side DB under the much smaller angle BLD; the apparent
magnitude being in the one case A' C, and in the other D B'.
In like manner, the right eye R sees D B under the large
angle BRD, and with an apparent magnitude D V ; while it
sees A C under the smaller angle ARC, and with an apparent
magnitude Co.'. Hence it follows, that, with both eyes, we
shall see the solid in perfect symmetry, with its summit C D
concentric with AB; and hence the reason is obvious why
the two dissimilar pictures in the retina give a resultant pic-
ture corresponding with the solid itself.

Quitting our solid frustum of a cone, let us now suppose
that its two dissimilar projections A BCD, abed, fig. 17, are
united by the two eyes L, R, converging their axes to a point
nearer the observer. By drawing lines from A, B, C, D,
a, b, c, d, to L and R, the centres of visible direction, it will be
seen that the circles A B, a b at the base, can be united only
by converging the optical axes to M, and the summit circles
CD, cD only by converging the axes to N. Hence mnop
will represent the solid frustum of a cone, whose axis is M N.
Now, all the rays which flow from any point of the two pro-
jections A B, a b, cross each other at the figure mnop; and,
consequently, this figure is seen by both eyes in identically the
same manner as if the rays which really emanate from the
plane figures had emanated from their points of intersection,
that is, from the outlines of the solid figure m n op.

In order to see the base m nt the optic axes must be con-
verged to M, or any other point of the base; and in order to
see the summit op distinctly, the axes must be converged to
N. But the distance M N is so very small, that the whole out-
line mnop will be seen with great distinctness; though it is
certain that every point of it, but one, is seen double.

The height MN of the cone, fig. ] 8, is = cot± A -coti A',
A, A' being the angles of the optic axes LMB, L N R, and
O L or O It radius. But as these angles are not known, we
may find MN thus: — Let D = distance OP; d = Ss, the di-
stance of the two points united at M; d = S's', the distance
of the two points united at N ; C = L R = 1\ inches. Then

MP-™; NP= M,; „„dMN = ^-j^,
C + d C + d' C + d C + d

When the two figures are united by converging the axes be-
yond P, the base mn of the line will be nearest the eye; and
consequently the cone will appear hollow. In this case,

M if -C_^ J* * -C-d' C-d C-d"

and the cone will be much larger than in the other case. If
we make

in Single and Binocular Vision, 449

D as 9*24 inches,
C = 2-50; then
rf=2-14;
d! = 2*42 ; and
M N = 0-283, the height of the cone.
Whereas, in the second case, M'N= 18*9 feet! When

C = d, M P = 5^ and M' F infinite.

Considering that the summit-plane op rises above the base
m n, in consequence of the convergency of the optic axes at
N, it may be asked, how it happens that the frustum still ap-
pears a solid, and the plane op, where it is, when the optic
axes are converged to another point M, so as to see the base
m n distinctly ? Should not the relief disappear, when the
condition on which it depends is not fulfilled ? But, instead
of the relief disappearing, the summit-plane op maintains its
position there as fixedly as if it belonged to the real solid; and it
ought to do so, for the rays emanate from it in exactly the same
manner, and form identically the same image on the retina
as if it were a real solid. Now, by the mere advance of the
intersection of the optic axes from M to N, the rays from the
circles A B, CD, &c. still produce the same picture on the
retina of each eye, and the only effect of the advance of the
point of convergence from N to M, is to throw that picture a
little to the right side of the optic axis of the left eye, and a
little to the left of the optic axis of the right eye; so that the
summit op still retains its place, and is merely seen double.

6. On the Doctrine of Corresponding Points.

Our celebrated countryman, Dr. Reid, calls those points in
the retina of each eye corresponding, which are similarly situ-
ated with respect to the foramen centrale, or centre of each
retina ; and he maintains that objects painted on those points
have the same visible position. He observes " that the most
plausible attempts to account for this property of the eyes
have been unsuccessful, and that it must be either a primary
law of our constitution, or the consequence of some more ge-
neral law which is not yet discovered." This doctrine has
been very generally admitted ; and if great names could have
given it currency, those of Newton and Wollaston, supported
by a number of anatomists and metaphysicians, might have
placed it, both optically and metaphysically, beyond the reach
of challenge. The doctrine of the semi-decussation of the
fibres of the optic nerve, as explained by Newton, gave great
support to the theory of corresponding points. The idea that
each fibre of the nerve divided itself into two, one of which

Phil. Mag. S. 3. Vol. 24. No. 161. June 1844. 2 G

450 Sir David Brewster on the Lata of Visible Position

went to a given point in the retina of one eye, while the other
went to the corresponding point in the retina of the other eye,
seemed to be at once an explanation and a proof of the doc-
trine.

Whether the anatomical supposition be true or false is a
matter of little consequence at present, as the doctrine which
it supports is not true excepting in the single case where the
optic axes are parallel, and in this case it is true only because
it is a necessary consequence of the general law of visible di-
rection.

Along with the theory of cor-
responding points, we must rank
the binocular circle of the Ger-
mans in which it is embodied.
Let R, L, fig. 18, be the right
and left eyes whose centres of
visible direction are C, 0, and
whose optic axes C A, 0 A,
converge to any point A.
Through the three points A, C,
0, describe the circle A B C 0.
This circle is called the Bino-
cular Circle, because if we take
any point B in its circumference,
and draw B C E, B 0 E', the
points E, E' on the retinae will
be corresponding points, that is, points equidistant from D
(because the angles A C B, A 0 B being equal, D 0 E' and
DCE are also equal), and consequently when the optic axes
are directed to A, an object at B will have its image formed
upon the corresponding points E, E', and will be seen single.

Now, when the optic axes are directed to A, a ray from B
will fall upon the left eye at L with a greater angle of incidence
than on the right eye at R ; and consequently it will strike the
retina at a point further from D in the left eye than in the
right eye ; that is, if the ray B R is refracted to E, the ray
B L will be refracted to some point e, and consequently the
lines of visible direction EC, eC will meet in a point without
the circle ABC. The real binocular curve, therefore, is every-
where without the circle. Hence the doctrine of correspond-
ing points is not true; and if it had been true, it would have
been so because it was a necessary consequence of a law of
visible direction.

B' JC

in Single and Binocular Vision, 451

7, On the Vision of Cameos and Intaglios*.

The beautiful experiment of converting a cameo into an in-
taglio, and an intaglio into a cameo, by monocular vision, is
well known. In 1825 I had occasion to investigate this sub-
ject, and in January 1826 I published an account of my ob-
servations, with an ample notice of the previous labours of
other authors f.

Mr. Wheatstone has ingeniously connected this optical
fallacy with the union of dissimilar images on the retina, though
he does not refer it to this union as its cause. After quoting
my previous explanation of the illusion, he makes the follow-
ing observations upon it: — "These considerations do not fully
explain the phenomenon, for they suppose that the image must
be inverted, and that the light must fall in a particular direc-
tion ; but the conversion of relief will still take place when the
object is viewed through an open tube without any lenses to
invert it, and also when it is equally illuminated in all parts %."
In thus objecting to the fullness of my explanation, Mr.
Wheatstone has overlooked the great number of experiments
by which I have supported it; and especially those facts in
which I observed the fallacy when the object is viewed with-
out even an open tube, — without inversion ; — with both eyes open,
and when it is placed in broad daylight. Mr. Wheatstone
then gives his own opinion as follows : — " If we suppose a
cameo and an intaglio of the same object, the elevations of
the one corresponding exactly to the depressions of the other,
it is easy to show that the projection of either on the retina is
sensibly the same§. When the cameo or the intaglio is seen
with both eyes, it is impossible to mistake an elevation for a
depression ; but when either is seen by one eye only, the most
certain guide of our judgement, viz. the presentation of a differ-
ent picture to each eye, is wanting ; the imagination therefore
supplies the deficiency, and we conceive the object to be raised
or depressed according to the dictates of this faculty. No
doubt, in such cases our judgement is in a great degree influ-
enced by accessory circumstances, and the intaglio or the relief
may sometimes present itself according to our previous know-
ledge of the direction in which the shadows ought to appear;
but the real cause of the phaenomenon is to be found in the

* The true explanation of this class of phenomena will be given in an
early Number. — D. B.

f This account was published anonymously in the Edinburgh Journal of
Science for January 1826, No. VII. vol. iv. p. 97; and a popular abstract
of it afterwards appeared in my Letters on Natural Magic, Letter V. p. 98.

% Philosophical Transactions, 1838, p. 383.

§ This is true only when they are not seen obliquely. — D. B.

2 G2

452 Sir David Brewster on the Law of Visible Position

indetermination of the judgement, arising from our more perfect
means of judging being absent*."

Now, what Mr. Wheatstone calls the real cause of the illu-
sion is no cause at all, — it is merely a previous state of the
mind which is favourable to the operation of the real cause.
Two eyes, like two witnesses, must always bear a better testi-
mony to truth than one; and, in the present case, the want of
the convergency of the optic axes to estimate the distance of
the highest and lowest points of the cameo and the intaglio,
undoubtedly favours the illusion, and allows the real cause to
influence the judgement; but even here this admission has its
limits, for in very shallow cameos and intaglios the illusion
takes place with both eyesf.

Without repeating in this place the various facts respecting
mother-of-pearl and other phaenomena in which I observed
the illusion when both eyes were used, I shall content myself
with quoting the following observation, made in Egypt by
Lady Georgiana Wolff'. M Lady Georgiana," says the Rev.
Mr. Wolff, " observed a curious optical deception in the sand
about the middle of the day, when the sun was strong ; all
the foot-prints and other marks that are indented in the sand,
had the appearance of being raised out of it ; and at those times
there was such a glare that it was unpleasant for the eye J."

8. On the Change in the Apparent Position of the Drawings
of Solid Bodies.

Although this illusion may have been previously observed,
yet I believe Professor Necker of Geneva is the first person
who has described and explained it. He mentioned it to me
in conversation in 1832; and afterwards sent me a notice of
it, which I published in the London and Edin- jpj„ jg
burgh Philosophical Journal §. Mr. Necker de-
scribes the illusion in the following manner.
" The rhomboid AX, fig. 19, is drawn so that
the solid angle A should be seen the nearest to
the spectator, and the solid angle X the furthest

* Philosophical Transactions, 1838, p. 384.

f When the cameo and intaglio are viewed very obliquely, one of the
causes of deception disappears. In the case of a cameo appearing depressed,
the depression disappears the instant that the shadow of the cameo en-
croaches distinctly upon the plane surface from which it is raised, because
an intaglio never can, however obliquely viewed, throw a shadow upon the
plane surface out of which it is excavated. For the same reason, an in-
taglio seen very obliquely will not rise into a cameo, because the shadow
on the plane surface is wanting.

t Journal of the Rev. Joseph Wolff, 1839, p. 189.

§ Vol. i. p. 334.

in Single and Binocular Vision. 453

from him, and that the face ACBD should be the foremost
while the face X D C is behind. But in looking repeatedly
at the same figure, you will perceive that at times the apparent
position of the rhomboid is so changed that the solid angle X
will appear the nearest, and the solid angle A the furthest, and
that the face A CDB will recede behind the face XDC, which
will come forward ; which effect gives to the whole solid a quite
contrary apparent inclination." Professor Necker observed
this change " as well with one as with both eyes," and he con-
sidered it as owing " to an involuntary change in the adjust-
ment of the eye for obtaining distinct vision ; and that when-
ever the point of distinct vision on the retina was directed on
the angle A, for instance, this angle, seen more distinctly than
the others, was naturally supposed to be nearer and foremost;
while the other angles seen indistinctly were supposed to be
further away and behind. The reverse took place when the
point of distinct vision was brought to bear upon the angle X."
Upon this explanation Mr. Wheatstone makes the following
observations: — "That this is not the true explanation is evi-
dent from three circumstances : in the fast place, the two
points A and X being both at the same distance from the
eyes, the same alteration of adjustment which would make one
of them indistinct would make the other so ; secondly, the
figure will undergo the same changes whether the eye be ad-
justed to a point before or behind the plane in which the figure
is drawn; and, thirdly, the change of figure frequently occurs
while the eye continues to look at the same angle. The effect
seems entirely to depend on our mental contemplation of the
figure, or of its converse. By following the lines with the eye,
with a clear idea of the solid figure we are describing, it may
be fixed for any length of time ; but it requires practice to do
this, or to change the figure at will. As I have observed
before, these effects are far more obvious when the figures are
regarded with one eye only."

In a case of this kind, where one eminent individual assures
us that he has proved his explanation to be true in three dif-
ferent ways, and another maintains that this explanation is
evidently not the true one from three different circumstances,
there must be a misapprehension to be removed as well as a
difficulty to be solved. It is impossible to read Mr. Necker's
paper without discovering that Mr. Wheatstone has entirely
mistaken his meaning, though the mistake is partly owing to
Mr. Necker's use of the phrase, "adjustment of the eye for
obtaining distinct vision." Mr. Wheatstone understands this
to mean the adjustment of the eye to A or X, as if they were
at different distances from the observer ; whereas Mr. Necker

454 Sir D. Brewster on the Law of Position in Vision.

clearly refers to that indistinctness of vision which arises from
distance on the retina from the foramen centrale, or point of
distinct vision. When the eyes are converged upon A, X is
seen indistinctly, and vice versa; and that this is Mr. Necker's
meaning is obvious from the following conclusion of his letter :
" What I have said of the solid angles is equally true of the
edges, — those edges upon which the axis of the eye, or the
central hole of the retina, are directed, will always appear for-
ward ; so that now it appears to me Certain that this little, at
first so puzzling phenomenon, depends upon the law of di-
stinct vision." That this is the true cause of the phamomenon
I have no hesitation in affirming. By hiding A with the finger,
or making it indistinct with apiece of dimmed glass, or throw-
ing a slight shadow over it, X appears forward, and continues
so when these obscurations are removed ; and the same effect
is produced by hiding X, A becoming then nearest to the eye.
This experiment may be still more satisfactorily made by
holding above the rhomboid a piece of ground glass (the
ground side being furthest from the eye), and bringing one
edge of it gradually down till it touches the point A, the other
edge being kept at a distance from the paper. In this way
A X, and all the lines diverging from A, become dimmer as
they recede from A, and consequently A becomes the most
forward point. A deep plano-convex lens, with its convex
side ground, will answer the purpose still better, the apex of
the lens being laid upon A or X ; or the effect may be still
further improved by making the roughness increase either
from the apex of a convex surface, or any fixed point of a
plane one.

Following out his general opinion of the superiority of bi-
nocular vision, Mr. Wheatstone remarks, that the illusion
which we have been examining is most obvious with one eye.
It is not so with my eyes ; and I conceive it should not be so,
as the convergency of the optic axes can have no efficacy in
preventing illusion when the figure occupies a plane surface.

In the course of the investigation which I have now brought
to a close, I have had occasion to observe many very interest-
ing phaenomena, which it would be out of place to describe at
present. They relate partly to the effects produced by uniting
unequal and dissimilar pictures which have a tendency to re-
present incompatible solids; — to the union of dissimilar pic-
tures, when the parts of the solid which they tend to produce
lie wholly or principally in a plane perpendicular to the line
joining the eyes and to the plane of the optic axes*; — to the

* Such as the magnified teeth of a saw, as in fig. 14, or a thin section
of a hexagonal prism whose axis is parallel to a line joining the eyes.

Royal Society, 455

union of pictures, one of which is more or less turned round
in its own plane ; — to the phenomena exhibited by uniting the
images of two similar real solids, the one elevated and the
other depressed; — to the union of dissimilar plane figures
which should at the same time give a solid in relief, and in the
converse of relief*; — and to the union of portions of dissimilar
figures, those which are wanting in the one figure existing in
the other. Among the singular effects produced under these
various conditions, nothing is more remarkable than the ten-
dency or desire, as it were, of the eyes, to unite and fix the
two pictures hovering before them, to convert them into some
figure of three dimensions (sometimes in relief, sometimes in
the converse, and sometimes in both at the same time) ; and
the suddenness with which the two images start into union,
give birth to a solid figure on which the optic axes are con-
verged, and release the eyes from that unnatural condition in
which they had previously been placed.

St. Leonard's College, St. Andrews,
January 1843.

LXV. Proceedings of Learned Societies.

ROYAL SOCIETY.
[Continued from p. 217.]

Dec. 7? A PAPER was read, entitled, " On a sudden rise and
1843. ■* fall of the Sea in the Dock-yard Creek, Malta, on the
21st and 25th June, 1843." By S. Napier, Esq., Master- Attendant.
Communicated by the Lords Commissioners of the Admiralty.

At 6 o'clock, a.m. on the 21st of June, the water was found to be
6 inches above the average height* and continued so till 6f , when it
rose to 18 inches, and in a few minutes sank to 3 feet 6 inches below
the average ; which oscillations continued till 8^ a.m., when it re-
sumed its usual level. On the 25th, a rise to the extent of 2 feet 6
inches above, followed by a fall of 3 feet below, the average, was
observed ; these alternations in height recurring four several times
on that day. The author was unable to assign any particular cause
for these extraordinary agitations of the sea.

December 14. — A paper was read, entitled, " Researches into the
Structure and Development of a newly-discovered Parasitic Ani-
malcule of the Human Skin, the Entozoon folliculorum." By Eras-
mus Wilson, Esq., Lecturer on Anatomy and Physiology in the
Middlesex Hospital. Communicated by R. B. Todd, M.D., F.R.S.

The animalcules which are the subject of this paper were disco-
vered above a year ago by Dr. Simon, who published a description
of their structure in the number of Muller's ' Archiv,' &c. for June

* In order to produce simultaneously this double effect, the lines of the
pyramid, for example, which are to give the converse of relief, should be
fainter than the other lines, or in different and feebler colours.

456 Royal Society.

184*2. This description was found by Mr. Wilson, who devoted to
the investigation six months of exclusive labour, to be, in many essen-
tial particulars, exceedingly inaccurate and erroneous. The present
paper contains the principal results-of the author's researches on
these singular animalcules, which inhabit the sebaceous follicles of
the human skin, and feed on the secretions that surround them. The
author enters into minute anatomical details of the structure of the
various organs, and more particularly of the apparatus by which
the head is retracted within the thorax, of the eyes, of the ova, and
the remarkable embryonic forms which are presented in the progress
of development of the young animal. He applies to this animalcule
the term entozoon, merely as signifying an inhabitant of the interior
of the body, and until a better and more appropriate appellation shall
have been assigned to it.

A paper was also in part read, entitled, " Miscellaneous Observa-
tions on Animal Heat." By John Davy, M.D., F.R.S.

December 21. — The reading of Dr. Davy's paper, entitled, " Mis-
cellaneous Observations on Animal Heat," was resumed and con-
cluded.

The author, in the first section of this paper, after adverting to
the commonly received opinion that all fishes are cold-blooded, and
noticing an exception, as he believes, in the instance of certain fishes
of the genus Thynnus and of the Scomber family, describes the ob-
servations which he made whilst at Constantinople, on the tempe-
rature of the Pelamys Sarda, when, in three different examples, he
found its heat to exceed that of the surface-water by 7°, and of the
deep water probably by 12°.

He adduces some observations and remarks on peculiarities in the
blood of the same fish, of the sword-fish and of the common tunny,
which he supposes may be connected with their temperature ; and
throws out the conjecture, that the constitution of their blood-globule,
formed of a containing and contained part, namely the globule and
its nucleus, may be to each other in the electrical relation of posi-
tive and negative, and may thereby act with greater energy in sepa-
rating oxygen in respiration.

In the second section, on the temperature of man in advanced old
age, he relates a number of observations made for the purpose of
determining the actual heat of persons exceeding eighty years of age;
the result of which, contrary to the commonly received opinion, is,
that the temperature of old persons, as ascertained by a thermome-
ter placed under the tongue, is rather above than below that of per-
sons of middle age ; and this he thinks may be explained by the cir-
cumstance, that most of the food used by old persons is expended in
administering to the function of respiration.

In the third section, on the influence of air of different tempera-
tures on animal heat, after alluding to what he had witnessed of the
rise and fall of the temperature of man on entering the tropics, and,
within the tropics, on descending from a cool mountainous region to
a low hot country, he adduces certain observations to show that in
this country similar changes of temperature take place in a few

Royal Society.

457

hours in breathing the air of buildings artificially heated ; and, in
confirmation, he describes the results of many observations made on
an individual in the very variable climate of Constantinople, where,
between March and July, in 1841, the thermometer ranged from
31° to 94°.

In the fourth section, he describes the observations which he made
to determine the effect of moderate exercise, such as that of walk-
ing, on the temperature of the body, tending to prove, that while it
promotes the diffusion of temperature and produces its exaltation in
the extremities, it augments very little, if at all, the heat of the cen-
tral and deep-seated parts.

A paper was also read " On the Thermal Changes accompanying
Basic Substitutions." By Thomas Andrews, M.D., M.R.I.A., Pro-
fessor of Chemistry in the Royal Belfast Institution. Communicated
by M. Faraday, Esq., D.C.L., F.R.S., &c.

The author gives an account of a series of experiments which he
made on the heat evolved during the mutual reaction of acids and
bases upon one another, from which he draws the general conclusion
that when the influence of all extraneous circumstances is eliminated
from the result, the change of temperature is determined by the na-
ture of the base, and not by the acid element of the combination.
Hence he deduces the general law that, when one base displaces
another from any of its neutral combinations with an acid, the heat
evolved or abstracted is always the same, whatever the acid element
may be, provided the bases are the same. The base employed in
the first set of experiments for displacing others was the hydrate of
potash in a state of dilute solution of known strength ; this was
rapidly mixed, in a suitable apparatus, with an equivalent solution
of the salt to be decomposed ; the change of temperature which re-
sulted was accurately determined, and the due corrections for the
influence of the vessels and the specific heats of the solutions and of
the precipitates produced, were applied. The experimental results
are stated in various tables, from which it appears that the changes
of temperature, referred to 1000 parts of water, were, with salts of

Lime from

Magnesia
Barytes .
Strontia .
Soda . .
Ammonia
Manganese
Proto-salts of iron
Zinc . .
Mercury ,
Lead . .
Copper ,
Silver . .
Sesquisalts of iron
The differences in the results of experiments with different acids,

— 0-33

to

— 0-38

- 0-10

5>

- 0-15

o-

o-

o-

o-

+ 0-4

»

+ 0-14

+ 0-72

»

+ 0-73

+ 1-04

5>

+ 1-15

+ 1-58

»

+ 1'63

+ 1-71

J>

+ 1-82

+ 1-81

JJ

+ 1-89

+ 2-77

»

+ 2-90

+ 2-90

>5

+ 3-18

+ 3-90

>>

+ 3-94

+ 4-25

?>

+ 4-28

458 Royal Society,

the author observes, are not greater than usually occur in chemical
reactions, in consequence of the uncertainty that exists with regard
to the accurate proportions of chemical equivalents. He points out
various circumstances in experiments of this nature, which tend to
affect the results and lead to inaccurate conclusions, if care be not
taken to guard against these sources of error. One of the principal
of these is the heat which is generally evolved by the separation of
a base, or new compound, in a solid form : and the author discusses
the influence of this change on the results deduced from his experi-
ments. He considers that these experiments sufficiently establish the
general principle announced in the beginning of his paper.

A supplementary note is added on the determination of the Spe-
cific Heat of Fluids.

January 11, 1844* — " An Account of a slight Shock of an Earth-
quake felt in the Channel Islands." By J. Elliott Hoskins, M.D.,
F.R.S. : in a Letter to P. M. Roget, M.D., Sec. R.S., &c. Commu-
nicated by Dr. Roget.

The phenomena described in this letter occurred simultaneously in
Jersey, Guernsey, Alderney, Serk, Heme, and Jethore. On Friday, the
22nd of December, at seven minutes before 4 p.m., a noise resembling
a distant thunder-clap was heard ; this was immediately followed by
sounds as of a railroad carriage rumbling over an irregular metallic
surface ; it was accompanied by distinct undulatory motion. This
again was succeeded by a shock; the whole lasting from 10 to 15
seconds. The barometer was uninfluenced, standing at 30*354 : a
light wind prevailed, varying from S.S.E. to S.S.W. During the
whole of the month the air had been peculiarly still, and the baro-
meter uniformly high ; the maximum, up to the above date, having
been 30*518, the minimum 30*042. The thermometer had ranged
throughout the month, from 47° to 52° during the day, and from
45° to 49° during the night.

Hundreds of persons agree as to having experienced a distinct
shock, their impressions varying according to the positions occupied
by the observers. Those inhabiting the solid granite structures of
the lower town conceived that heavy masses of furniture were over-
turned and moved in the apartments above or below them: they
were not, however, so conscious of vibratory motion as those in the
less substantial houses of the upper part of the town, or as those in
the open air. In many houses, this vibratory motion was so violent as
to cause much alarm, and was accompanied by crashing sounds, as
though roofs and chimneys were falling ; in some instances, chimney-
pots were thrown down ; suspended lamps were observed to wave ;
bells rang spontaneously ; the vane of the town church waved, and
one of its bells struck twice.

Persons in the open air were sensible of an undulatory motion,
tending from the S.W., which occasioned unsteadiness of footing,
and in some cases a transient feeling of nausea. A steam-engine in
the Serk mines was remarked to suspend one out of its usual five
strokes per minute ; the engineer was alarmed lest this should be a
precursor of bursting of the boiler. The massive granite works of

Royal Society. 459

St. Sampson's quay were so shaken, that glass vessels situated on
various parts were thrown off. Two gentlemen engaged in Daguer-
reotype experiments on the ramparts of a fortification founded on a
solid granite rock, felt the whole to vibrate. The crews of sailing-
vessels beating up in the " roads," also felt the shock ; those below
rushing on deck under the impression that the vessels had struck on
a rock.

The testimony of a great number of witnesses leaves no doubt as
to the distinctness and strength of the shock. It was also felt, though
in A slighter degree, in the neighbourhood of St. Malo, and near
Brixham in Devonshire.

January 18.—" On a new Method of Analysis." By George Boole,
Esq. Communicated by S. Hunter Christie, Esq., Sec. R.S., &c.

The purport of this paper is to exhibit a new form of analysis,
and to found upon it a new theory of Linear Differential Equations^
and of Generating Functions. The peculiarity in the form of the
analysis consists in the linear differential equation, instead of being
represented, as it has hitherto been, under the type

■ft sf'~l

xflJLiL + Xl d *■ +Xnti = X,

0 dxn x dxn~l n

X0, X„ &c. being functions of the indepehdent variable x, being
exhibited in the form

/0(D)«+/I(D)^i» + /.(D)«*i« = U;

in which e = x, and/0 (D), fx (D), &c. imply functional combina-
tions of the symbol D, which, for the sake of simplicity, is written in

place of — . This the author calls the exponential form of the

equation J and he, in like manner, designates the analogous forms
of partial and of simultaneous equations. What he conceives to be
the great and peculiar advantage of the exponential form, both as
respects the solution of linear differential equations, and the theory
of generating functions, is that the necessary developments, trans-
formations and reductions are immediately effected by theorems the
expression of which is independent of the forms of the functions
fQ (D),/i (D), <&c. Accordingly it may be shown that various for-
mulas which have been given for the solution of linear differential
equations, with those in which Laplace's theory of generating func-
tions is comprised, interpreted into the language of the author, are
but special cases of theorems dependent on the exponential form
above stated, and Which are susceptible of universal application.

The common method of effecting the integration of linear differ-
ential equations in series fails when the equation determining the
lowest index of the development has equal or imaginary roots. In
a particular class of such equations of the second order, Euler has
sho\vn that log. x is involved in the expression of the complete inte-
gral : but this appears to be merely a successful assumption ; artd
the rule of integration demonstrated in the present paper admits of
tto such cases of exception whatever.

The finite solution of linear differential equations may be attempted

460 Bmjal Society.

by resolution of the proposed equation into a system of equations of
an inferior order. This method applied to the linear equation under
its usual forms leads to the well-known solution of equations with
constant coefficients : and when applied to the same equation under
the exponential form, it gives a result embracing the solution not
only of equations with constant coefficients, but also of a large
class of equations with variable coefficients.

The author treats, — 1st, of the solution of linear differential equa-
tions, total and partial, in series ; 2ndly, of their finite integration ;
3rdly, of the theory of series, or inverse method of development ;
4thly, of linear equations of differences, total and partial, of certain
miscellaneous applications, chiefly in the field of definite integrals,
single and multiple.

January 25. — " A Description of an extensive Series of the Water
Battery ; with an account of some Experiments made in order to test
the relation of electrical and chemical action which takes place
before and after completion of the Voltaic Circuit." By John P.
Gassiot, Esq., F.R.S.

In a former paper, which was printed in the Philosophical Trans-
actions for 1839, the author described a series of experiments made
with some powerful voltaic batteries, for the purpose of determining
the possibility of obtaining a spark before the completion of the cir-
cuit. This anticipated effect was not, however, produced. A short
time after, Mr. Cross stated that he had succeeded in procuring a
spark from a battery of 1626 cells of copper and zinc, acted upon by
river water. The author, pursuing his researches, constructed a bat-
tery consisting of 3520 pairs of copper and zinc cylinders, each pair
being placed in a separate glass vessel, well covered with a coating
of lac varnish, and insulated by being placed on slips of glass covered
on both sides with a thick coating of lac. The cells were placed on
44 separate oaken boards, also covered with lac varnish, each board
carrying 80 cells, and sliding into a wooden frame, where they are
further insulated by resting on pieces of thick plate-glass, similarly
varnished.

In describing the effects which this apparatus has produced, the
author endeavours to draw a distinction between the static and the
dynamic effects of the developed electricity, and treats of each se-
parately. The conclusions to which he is led from the series of ex-
periments narrated in this paper, are the following : —

1. The elements constituting the voltaic battery assume polar ten-
sion before the circuit is completed, even in a single cell ; this polar
state being shown to exist by the action exerted on the electroscope
being different at each polar extremity of the battery.

2. The tension, so produced, when exalted by a succession of series,
is such, that a succession of sparks passes between the polar extre-
mities of the battery before their actual contact.

3. The static effects precede, and are independent of the com-
pletion of the voltaic circuit, as well as of any perceptible develop-
ment of chemical or dynamic action.

4«. When the current is established, either by actual contact of the
extremities, or merely by their approximation, so as to admit of a

Royal Society. 461

succession of sparks, its dynamic effects on the galvanometer are the
same in both cases ; each spark producing a constant deflection of
the needle. It is hence inferred that the current, even when the
circuit is closed, may be regarded as a series of discharges of elec-
tricity of tension, succeeding each other with infinite rapidity.

5. In a battery, of which the chemical elements have but a feeble
mutual affinity, as is the case with the water battery, the tension rises
very slowly.

6. In order to produce static effects in the voltaic battery, it is an
indispensable requisite that the elements be such as are capable of
combining by their chemical affinities : and the higher those affini-
ties are exalted, the smaller is the number of parts composing the
series requisite to exhibit the effects of tension. The static effects
elicited from a voltaic series, afford, therefore, direct evidence of the
first step towards chemical combination, or dynamic action.

The author observes, in conclusion, that the chemical effects, when
obtained in most of the experiments he has described in this paper,
are very feeble ; but are precisely the same in character as those ex-
hibited by the more powerful voltaic combinations ; and he thinks
it may fairly be concluded that the rationale of each is the same, and
that they differ only in the amount of action.

February 15. — " Some further Observations and Experiments
illustrative of the Cause of the Ascent and continued Motion of the
Sap," in continuation of a Paper presented to the Royal Society in
November 1842. By G.Rainey, Esq. Communicated by P.M.Roget,
M.D., Sec. R.S.

The author here gives an account of some experiments which he
has lately made, tending, in his opinion, to corroborate the opinions
he advanced in his former paper; namely, that the ascending sap is
situated in the intercellular and intervascular spaces of the plant, and
that its passage into the cells is effected by the action of endosmose,
which the intervening membranes, whether living, or deprived of
vitality, exert upon that fluid. He found that portions of many plants,
such as Anthriscus vulgaris, and the Lapsana communis, absorb a
much larger quantity of fluid when they are immersed in pure
water, than when similarly immersed in a solution of gum-arabic ;
and that, in the latter case, the remaining portion of the solution is
of the same specific gravity as before any part has been absorbed by
the plant. By a similar process, the author conceives, the fluid which
is derived from the earth, and has passed into the intercellular spaces
of the cotyledons, are imbibed by its cells by endosmose ; while at
the same time a fluid containing sugar is passing, by exosmose, out
of these cells into the intercellular and intervascular tissue, and thence
into the corresponding tissue of the peduncle and young stem ; it
there meets with, and is diluted by the water ascending in the same
tissue from the roots, and the mixture is afterwards distributed over
every part of the plant.

February 22. — " On the Temperature of the Springs, Wells and
Rivers of India and Egypt, and of the Sea and Table Lands within
the Tropics ; with a few Remarks on M. Boussingault's mode of as-

462 Royal Society,

certaining the mean temperature of Equinoctial Regions." By Lieut.
Newbold, of the Madras Army, F.R.S.

The author adverts to the deficiency of information which has
hitherto existed as to the temperature and chemical composition of
the springs and rivers both of India and of Egypt ; and also as to
their geographical and geological relations. He gives, in the present
paper, the details of a great number of observations which he has
made on these subjects, and which he thinks may prove a useful con-
tribution to Indian hydrography, as well as afford more exact data
for philosophical inquiry. The observations extend, at irregular in-
tervals, from Alexandria to Malacca, or from 51° 13' of northern
latitude to within 2° 14' of the Equator, and between the meridians
of 27° and 103° of east longitude. In the columns of the register,
the date of the observation, the latitude, longitude, approximate
height above the sea, nature of the surrounding geological formation,
depth to the surface of the water, depth of the water itself, tempera-
ture of the air, and approximate annual mean of the climate in which
the wells, &c, occur, are, as far as practicable, specified, A column
of remarks is added, containing observations on the chemical nature
of the water, and on the size of the wells and springs, and the result
obtained by other observers.

It was found, in general, that in low latitudes the temperature of
the deepest wells and springs is a little higher than the mean tempe-
rature of the air ; although there occur a few exceptions, especially
in the neighbourhood of a high range of hills, whence there probably
arise cold springs, having their source at an elevation considerably
above that of the plain where the water makes its appearance.
Springs which are strongly saline and sulphureous, have, on the
average, a higher temperature than those of pure water. Both saline
and cold springs are found occurring within a few feet from thermal
and freshwater springs : a fact which the author is disposed to ascribe
to their rising through different seams of the subjacent strata, often
much inclined ; and to the different depths and heights, above and
below the crust of the earth, from which the supply of water is de-
rived. Wells, and particularly those having a small surface, which
are much used for purposes of irrigation, thereby acquire an artificial
increase of temperature. The temperature of shallow exposed wells,
springs and rivers, especially those which have sandy beds, is subject
to diurnal fluctuation from the more powerful influence of the atmo-
sphere : and the surface water of deep wells partakes of these vicis-
situdes to a depth varying according to the transparency of the water,
the extent of surface, degree of exposure and clearness of the sky.
In muddy water, the surface is heated to a greater extent : but at the
depth of a foot or two, it is less affected by the heat of the solar rays
than clear water.

With regard to Boussingault's proposal of an expeditious mode of
ascertaining the approximate mean temperature of equinoctial re-
gions, which consists in sinking a thermometer in the soil, perforated
to the depth of about a foot beneath the surface, in a situation shel-
tered from the direct rays of the sun, from nocturnal radiation, and

Royal Society, 463

from the infiltration of water, the author found that the application
of this method gave the following results, namely, that the soil at the
depth of a foot is subject to an annual, and, in light soils, to a diurnal
variation, regulated in its amount by the relative intensity of the solar
rays, and the quantity of radiation, depending, of course, on the state
of the atmosphere, and the degree of shelter afforded to the sur-
face.

February 25. — " On the Electrolysis of Secondary Compounds."
By John Frederic Daniell, Esq., D.C.L., For. Sec. U.S., and Profes-
sor of Chemistry in King's College, London ; and W. A. Miller, M.D.,
Demonstrator of Chemistry in the same College.

The authors of this paper have further prosecuted the inquiry into
the phenomena of electrolysis, commencing from the point to which
it had been carried by Professor Daniell in his papers published in
the Philosophical Transactions for 1839 and 1840. He had there
shown, that in the electrolysis of neutral saline solutions, if the metal
is one of those which do not decompose water at ordinary tempera-
tures, it is precipitated in the metallic state at the platinode ; but if
it belong to the class of those which, at ordinary temperatures, do
decompose water, then an equivalent of the oxide is liberated at the
platinode, while an equivalent of hydrogen makes its escape in the
gaseous form from the same electrode ; the acid, in both cases, being,
at the same time, liberated at the zincode, accompanied by an equi-
valent proportion of oxygen. On comparing these results with those
of an independent voltameter included in the same circuit, it was
found that a certain definite proportion of the force which resolves
a single equivalent of a simple electrolyte into its anion and cation,
produces the resolution of a full equivalent of a complex electrolyte
into a simple metallic cation and a compound anion. When ammonia-
cal salts in solution were thus decomposed, ammonia, with an equiva-
lent of hydrogen, was liberated at the platinode ; while the acid, with
an equivalent of oxygen, was evolved, as before, at the zincode,

Experimental evidence was thus obtained in support of two im-
portant theories ; namely, the ammonium theory advanced by Ber-
zelius ; and the binary theory of salts propounded by Davy ; in which
latter theory, all saline compounds are regarded as being formed on
the type of the salts of the hydro-acids. This binary composition of
salts is, in the present paper, proved to exist, not only when the salts,
previously held in solution by water, are decomposed by the voltaic
current, but also when the fused anhydrous salt is electrolysed : for
example, metallic silver in crystals is deposited upon the platinode,
when fused nitrate of silver is included in the circuit.

On examining, by the current, the monobasic, dibasic, and tri-
basic phosphates, the authors found that there were three distinct
modifications of the acid transferred. From the monobasic phos-
phates there was obtained the metaphosphoric acid ; from the dibasic
salts, pyrophosphoric acid ; and from the tribasic salts, the ordinary
phosphoric acid was set free at the zincode. The acids were trans-
ferred into weak alkaline solutions and recognised by their appro-
priate tests. The view entertained by Professor Graham of the
composition of these salts is therefore completely confirmed.

464 Royal Society »

On the other hand, the authors found, by similar experiments made
with the yellow and the red prussiates of potash, that only one com-
pound of cyanogen and iron, or ferrocyanogen as it exists in the
yellow salt, is evolved at the zincode ; and they not only converted
the yellow into the red salt by electrolytic action, but, conversely,
reproduced the yellow from the red.

In pursuing their researches on double salts, a new order of facts
was brought to light, which clearly proved that although the two ions
of the electrolyte are always evolved in equivalent proportions, yet
that they are not transferred in equivalent proportions to the re-
spective electrodes ; that some bases, such as copper, zinc, iron and
alumina, do not travel at all towards the platinode ; that some, as
magnesium, do so in small proportion only; and that others, as
barium and potassium, are transferred in greater abundance ; those
whose oxides are most soluble appearing to travel most easily. On
the other hand, the acids, whether forming soluble hydrates or not,
seem all to travel towards the zincode, in proportions dependent prin-
cipally on the nature of the base with which they are united.

The curious phenomena which have thus been brought to light,
concur in establishing the general fact, that the disengagement of the
cation and anion of an electrolyte in equivalent proportion is not
always affected, as is commonly represented, by their simultaneous
transfer in opposite directions to their respective electrodes, in the
exact proportion of half an equivalent of each ; but that it is some-
times brought about by the transfer of a whole equivalent of the anion
to the zincode, whereby a whole equivalent of the cation is left un-
combined at the platinode, or by the transfer of unequivalent portions
of each in opposite directions, making together a whole equivalent
of matter transferred either to one electrode or to the other; or, in
other words, by the transfer of a quantity of matter capable of ex-
ercising one equivalent of chemical force : so that when the anion
transferred to the zincode exceeds half an equivalent, the cation trans-
ferred to the platinode is, in an equal proportion, less than half an
equivalent, and vice versa ; the anion and cation set free being always
in equivalent proportions. In no case, however, has there been ob-
served the transfer of a whole equivalent of the cation to the exclu-
sion of the anion.

These facts, the authors conceive, are irreconcileable with any of
the molecular hypotheses which have been hitherto imagined to ex-
plain the phenomena of electrolysis.

March 21. — "A description of certain Belemnites, preserved,
with a great proportion of their soft parts, in the Oxford clay at
Christian Malford, Wilts." By Richard Owen, Esq., F.R.S., &c,
Hunterian Professor of Anatomy and Physiology in the Royal Col-
lege of Surgeons.

The author describes, in the present paper, specimens of Belemnite,
discovered in the Oxford-clay at Christian Malford, Wilts, and
which are remarkable for the preservation of many of the soft parts
of the animal. After alluding to the various opinions promulgated
by different authors respecting the nature and affinities of this ex-
tinct animal, he adverts more especially to the discovery of the ink-
w* .lot

Royal Society. 465

bag of the Belemnite, which was published in the Zoological Trans-
actions, vol. ii., and in the Cyclopaedia of Anatomy and Physiology
(Art. Cephalopoda). This discovery led him, on the strength of
deductions from the physiological relations of this organ, to re-
move the Belemnite from the Polythalamacea of De Blainville, and
place it in the higher order of the naked Cephalopods.

The structure of the shell is next discussed, and the spathose dart,
or guard, is proved to be the result of original organization, both
by its microscopic structure and by the fact that the chambers of
the phragmocone have not been infiltrated by mineral substance in
any of the specimens described : the name phragmocone being applied
to the chambered and siphonated conical division of the compound
shell of the Belemnite ; and the term alveolus being restricted, in
the present paper, to the socket or cavity at the base of the guard,
in which the phragmocone is lodged. A detailed description is given
of the sheath of the phragmocone and of the structure of the cham-
bers. The state of preservation of the present specimens has enabled
the author to describe the form and extent of the mantle — its con-
tinuation over the exterior of the shell, and the arrangement of its
muscular fibres. The animal is provided with two lateral fins of a
semi-oval figure, which are attached to the middle of the mantle, in
advance of the spathose dart.

The muscular fibres of the fins, the infundibulum and its muscles
are next described ; and also the head, the eyes, which are large and
sessile, and the cephalic arms, which are eight in number ; together
with traces of two slender superadded tentacala. The ordinary arms
are furnished with a double alternate row of sharp horny hooks, as in
some existing species of Onychoteuthis, but the arms are relatively
longer. Their muscular structure is traced in the fossil specimens,
and compared with that in the recent Decapoda. The ultimate, or
primitive fibres of the muscles of the Belemnite agree in size with
those in the Onychoteuthis ; but the character of the transverse striae,
which is feebly developed in the primitive muscular fibre of the Ce-
phalopods, is not preserved in the fossil. Of the interior organs
of the Belemnite, besides the ink-bag and duct, which had been be-
fore discovered by Drs. Buckland and Agassiz, the remains of the
horny lining of the gizzard are preserved in the present fossils.

Thus the deduction that the higher, or dibranchiate type of Ce-
phalopodal organization is necessarily associated with the presence
of the atramental apparatus, is established by the demonstration, in
these fossil Belemnites, of a fleshy mantle, inclosing the shell, and
provided with a pair of muscular fins, of large and sessile eyes, and
of few, but large and complex cephalic arms.

The author concludes by pointing out the more immediate affini-
ties of the Belemnites, and showing that it combines characteristics
which are now divided amongst distinct genera : as, for example,
first", a complex internal shell, divisible into the same principal parts
as that of the Sepia, but one of which has, secondly, the same essen-
tial chambered structure as the shell of the Spirula ; thirdly, unci-
nated cephalic arms, as in the Onychoteuthis ; and lastly, an ad-
vanced position of rounded fins, as in the Spirula and Rossia.

Phil. Mas. S. 3. Vol. 24. No. 1 6 1 . June 1844. 2 H

466 Royal Society.

The paper is illustrated by drawings of the specimens described,
with microscopic views of the shell and muscular tissue, and a re-
storation of the Belemnite according to the data afforded by the pre-
sent fossils.

April 18. — 1. Note in addition to Mr. Gassiot's paper on the
"Water Battery." The author here describes an instrument which
he has recently constructed, and by means of which he is enabled
with great facility, and without the aid of Zamboni's pile, to test the
tension in a single series of the voltaic battery.

2. "On the production of Ozone by Chemical Means." By Pro-
fessor Shoenbein, in a letter to Michael Faraday, Esq., D.C.L.
F.R.S. Communicated by Dr. Faraday.

The author conceives that of the two gaseous principles which
are simultaneously produced during the slow action of phosphorus
upon atmospheric air, and which have opposite voltaic characters,
that which exerts electro-positive properties is composed of vapo-
rized phosphorus, conjoined with particles of phosphatic acid ; and
the other, which is electro-negative, is identical with ozone, or the
odoriferous principle which is disengaged at the positive elec-
trode during the electrolysis of water. His opinion is founded on
the odour of the one not being distinguishable from that of the
other.

3. "Contributions to Terrestrial Magnetism." No. VI. By Lieut.-
Colonel Sabine, R.A., F.R.S.

This portion of the series consists of observations made on board
Her Majesty's ships Erebus and Terror, from June 1841 to August
1842, in the Antarctic Expedition under the command of Captain
Sir James Clark Ross, R.N., F.R.S. It comprises the result of the
operations conducted during the second year of the expedition, when
it proceeded early in July 1841, from Hobarton to Sydney, and
thence to the Bay of Islands in New Zealand, remaining there till
November, and reaching, in February 1842, in latitude 78°, the icy
barrier which had stopped their progress in the preceding year.
Quitting the antarctic circle in March, and keeping nearly in the
60th parallel, they crossed the whole breadth of the Southern
Pacific Ocean to the Falkland Islands, where they arrived in April
1842.

On a general review of the magnetic declination in the southern
hemisphere, the phenomena are found to present the same obvious
and decided features of a duplicate system as those of the northern.
Particular attention is given to those lines traversed by the ship's
course where the needle attains its maximum declination, whether
easterly or westerly, as affording valuable data for the estimation of
secular variations. The results obtained by the present expedition
confirm the conclusion deducible from those of previous navigators ;
namely, that the spaces in the Southern Pacific, distinguished by
certain magnetic characters, undergo a movement of translation, of
which the general direction is from east to west ; a direction which
is the opposite to that in which a similar change takes place in the
corresponding regions of the northern hemisphere ; namely, in the
Siberian quarter, where the secular movement is from west to east.

Royal Society. 467

April 25. — " On the production of Ozone by Chemical Means."
By C. F. Shoenbein, Professor of Chemistry at Basle, in a second
letter to Michael Faraday, Esq., D.C.L. F.R.S. Communicated
by Dr. Faraday.

The author adduces further evidence in support of the opinions
he advanced in his former communication relative to the identity
of the odoriferous principles which are disengaged during electric
discharges in common air, during the electrolysis of water, and
during the slow action of phosphorus upon atmospheric air. This
principle, termed Ozone, he regards as being a simple body, and a
constituent of azote, which he believes to be a compound of hydro-
gen and ozone ; and he explains the disengagement of this latter
element, which he considers as analogous in its chemical character
to chlorine, by the partial decomposition of azote, in consequence
of its hydrogen combining with oxygen, in the several processes
above-mentioned during which ozone makes its appearance.

" On the existence of Phosphoric Acid in Rocks of igneous
origin." By George Fownes, Esq., Ph. D., Chemical Lecturer in
the Middlesex Hospital Medical School. Communicated by Thomas
Graham, Esq., F.R.S.

The author has, by careful analysis, ascertained the presence of
phosphoric acid in various rocks of igneous origin. Those which
he examined were principally the following; namely, 1. The fine
white porcelain clay of Dartmoor, resulting from the disintegration
of the felspar of the granite of that district. 2. Dark grey vesi-
cular lava from the Rhine, used at Cologne as a building-stone.
3. White trachyte from the Drachenfels, near Bonn. 4. Dark
red, spongy, scoriaceous lava from Vesuvius. 5. Compact, dark
green basalt, or toadstone from Cavedale, Derbyshire. 6. Dark
blackish-green basalt from the neighbourhood of Dudley, termed
Rowley-ragg. 7- Ancient porphyritic lava, containing numerous
crystals of hornblende, from Vesuvius. 8. A specimen of tufa, or
volcanic mud, also from Vesuvius.

The author infers from his analysis that phosphoric acid is a very
usual component part of volcanic rocks, and is a principal source of
the remarkable fertility possessed by soils derived from their disin-
tegration.

May 2. — 1. " Ranges of the Barometer and Sympiesometer on
board H.M.S. f Alfred,' in the River Plate, between the 1st of July
and the 31st of December, 1843." Communicated by Captain Beau-
fort, R.N., F.R.S.

This paper is a register of the results of daily observations of the
heights of the barometer, sympiesometer and thermometer, the direc-
tion of the wind, and state of the weather during the above period.

2. " Remarks on the amalgamation of Silver Ores in Mexico ;
with an account of some new combinations of Copper, Oxygen and
Chlorine." By John Christian Bowring, Esq. Communicated by
S. Hunter Christie, Esq., Sec. R.S.

The process employed in Mexico for amalgamating ores con-
taining sulphurets of silver, and which consists in adding to them a

2H2

468 National Institute of the United States.

solution of bichloride of copper with chloride of sodium, is explained
by Sonneschmidt, Humboldt, and Boussingault, on the supposition
that a chloride of silver is formed at the same time that the sulphur
combines with the copper. The author calls in question the truth
of this theory, and proposes certain modifications of the process by
the employment of a combination of deutoxide of copper with the
bichloride, until an oxy-chloride is formed, and then adding finely
precipitated copper, by which a salt of a brick-red colour is ob-
tained, insoluble in water, and at a temperature of 200° Fahr.
speedily reducing sulphuret of silver to the metallic state.

3. " Experimental evidence in support of the secretion of Carbon
by animals." By Robert Rigg, Esq., F.R.S.

The author finds that the mean of the results of different experi-
mentalists as to the quantity of carbon excreted by respiration from
adults, during twenty-four hours, is 5963 grains ; whereas the
weight of the carbon contained in the whole of the food, both solid
and liquid, received into the body during the same period, as ascer-
tained by the analysis of each article of diet, made by the author,
falls very short of that quantity ; varying in different cases from
3002 to 4800 grains. The same inference is drawn from experi-
ments made on a mouse, weighing 181 grains, confined in a wire
trap for twenty-eight days ; during which time it consumed food
containing 544'5 grains of carbon, and gave out, in the respired air,
741*2 grains of carbon, being 196*7 grains more than it had re-
ceived ; and it had also gained in absolute weight 27 grains. The
conclusion which the author deduces from these experiments is, that
carbon is actually formed, or secreted by animals.

May 9 — " On the Hyssop of Scripture." By J. F. Royle, M.D.,
F.R.S., &c.

Many attempts have at different times been made, by various
authors, to identify the plant which, in our authorized version of the
Scriptures, is translated Hyssop. The author enters at large into
the history of the speculations of former writers on this subject ;
and after an elaborate investigation, is led to the conclusion that this
plant is the Capparis spinosa of Linnaeus, or Caper plant, a shrub
abundantly met with in the south of Europe, where it appears to be
indigenous, and also generally on the islands and coasts of the
Mediterranean, as well as in Lower Egypt and in Syria.

NATIONAL INSTITUTE OF THE UNITED STATES.

The first annual meeting of this Institute was held in Washington
during the first week in April, and was very numerously attended by
scientific men from all parts of the United States.

The establishment of these annual meetings in America will be
attended, we doubt not, with the happiest results. A year ago the
American Philosophical Society in Philadelphia held its centennial
celebration, a hundred years having elapsed since it was founded by
Franklin. Up to that time it was generally feared that any attempt to
bring together scientific men would not be successful, partly owing to
the remoteness of their residences, but mainly to that peculiar dispo-

National Institute of the United States. 469

sition which, arising in the political institutions of that country, per-
vades all classes of men and affects all attempts at organization ; a
feeling which is the reverse of every thing like centralization. The
Philadelphia meeting demonstrated the possibility of success, not-
withstanding these adverse circumstances.

The National Institute, therefore, under the immediate auspices
of the government, proposed to hold in Washington, during the first
week in April, a general meeting, and issued a circular inviting those
interested in the advancement of knowledge to attend.

At the first session the chair was taken by the President of the
United States, the cabinet ministers being present, and many mem-
bers of both houses of Congress.

The President in a very appropriate manner stated the objects of
the meeting, and briefly addressed the members of the Institute.

A preliminary oration was made by the Hon. It. Walker, senator
from Mississippi ; he gave a general sketch of the progress of science
in America, of the different philosophical discoveries which had been
made in that country, and dwelt on the necessity of an organized
union among the men of science.

The scientific business of the Institute was then opened by a paper,
read by Professor Draper of the University of New York, on the
physical constitution of the solar rays, and on the existence of a new
imponderable principle ; the results given in this communication we
expect to publish in this Journal shortly. Prof. Loomis, of Western
Reserve College, Ohio, then read a paper on the great comet of
1843. Iff aoiauhaoo

The Institute continued its sittings for seven days, during which
a great number of very interesting communications were made ;
these embraced the various departments of philosophy and letters.
Among them we may mention the following as being those con-
nected with physical and natural science : —

Prof. Bache, on science in Europe and America.

Lieut. Maury, U.S.N., on the Gulf Stream.

Prof. Hallowell, of the Medical College at Washington, on certain
chemical changes attended with a disengagement of caloric.

Prof. MacCulloh, of Jefferson College, Pennsylvania, on the at-
traction of a planet for a material point in space.

Capt. Mordecai, of the United States Ordnance Department, on a
ballistic pendulum used for experiments in gunnery at the arsenal.

Prof. Locke, of Cincinnati, Ohio, on some geological, magnetic,
and meteorological observations made at Lake Superior.

Prof. Mather, of the University of Ohio, on the physical geology
of the United States.

Prof. Jacobs, of Gettysburg College, Pennsylvania, on the Indian
Summer.

Mr. Gill, of New York, on some relations of mathematics to na-
tural science.

Mr. Agnew, of New York, on the glacier theory.

Prof. Norton, of Delaware College, on an extension of the nebular
hypothesis. MjriJ at ylnnsra iud

470 Intelligence and Miscellaneous Articles.

Capt. Swift, a description of the base-line of Long Island, mea-
sured in 1834 for a survey of the coast of the United States.

Prof. Bailey, of the Military Academy at West Point, on the fossil
polythalamiaB of the United States.

Dr. Van-Buren, U.S.A., on the effects of very large doses of qui-
nine on the human system.

Dr. Wayland, President of Bronn University, on observations on
the atmosphere made by captains of packet ships.

Prof. Hamilton, of the University of Nashville, Tennessee, on cer-
tain meteorological facts observed at Tennessee.

Mr. Espy, on meteorology.

Dr. Hare, of the University of Pennsylvania, on meteorology.

Mr. John Tyler, jun., on the theory of one electric fluid.

Dr. Patterson, Director of the United States Mint, Philadelphia,
on the centre of population of the United States.

Prof. Bache, on the magnetical and meteorological observations
made under the direction of the War department at the Observatory
in Philadelphia.

Prof. Bache, by direction of the Treasury Department, exhibited
proof impressions of five sheets of the map of New York Bay and
Harbour, surveyed under the superintendence of Mr. Hassler.

An address was delivered by the Hon. John Quincy Adams, ex-
president of the United States.

The session was concluded by an address by the Hon, J. C.
Spencer, Secretary of the Treasury.

LXVI. Intelligence and Miscellaneous Articles.

OBSERVATIONS ON AFRICAN GUANO. BY W. FRANCIS.

THE discovery of considerable deposits of this valuable manure
on several small islands off the coast of Africa, where it may be
had free of expense, has induced numerous merchants and shipowners
to dispatch several vessels for its importation to this country. From
one of these, the " Canning," which recently arrived in the port of
Bristol, we have received, through the kindness of our friend
J. Turner, Esq., a sample, accompanied with the following letter,
which, as it supplies some information respecting the localities whence
the article is obtained, will, we doubt not, be read with interest by
many of our readers : —

"My dear Sir,

" The sample of African guano, which I left with you, and which
you have kindly undertaken to analyse, was imported into Bristol,
where it is selling at £8 per ton. It is found on several small
islands in the neighbourhood of Angra Pequeiia, on the western
coast of Africa, between 26° and 27° south latitude. The deposit
is very considerable, reports say from twenty to thirty feet deep ;
the sample I sent you was taken up twenty feet below the surface.

" The discovery of these beds will lead to the discontinuance, for
the present, of the importation from South America, as the African

Intelligence and Miscellaneous Articles. 471

voyage is performed in half the time occupied by the other ; and,
moreover, the Peruvian government levy an export duty of £3 per
ton, whereas the African is collected without any such payment,
there being few, if any, natives in the neighbourhood to interfere
with its removal. Already many thousands of tons of shipping have
been dispatched to the coast for cargoes, and other vessels are daily
departing on the same errand.

" Mr. G. Thompson, of the firm of Borrodaile and Thompson, who
travelled in those parts in 1823, describes the natives as 'a tribe of
Hottentots called Namaquas; a pastoral people, resembling the
aboriginal tribe of the Cape Colony in their general characteristics ;
living chiefly on milk ; addicted to a roaming life ; and of a dispo-
sition mild, indolent and unenterprising.'

" As regards the probable establishment of trade with the natives,
ivory, horns, hides, and perhaps gums, might be obtained from them
in exchange for tobacco, beads, &c. The country improves in fer-
tility towards the north, in which direction, at about a hundred
miles distance from Angra Pequena, the Damaras country com-
mences ; and Mr. Thompson reports it to be ' very rich in copper
ore, which is smelted and worked by the natives.'

" Yours, &c,
"J.Turner."

The guano, in the state in which it was received, formed a moist
chocolate-brown powder, intermixed with numerous particles of a
whitish substance. It possessed no urinous odour, but smelt strongly
of ammonia. On examination under the microscope, no crystals of
any kind could be detected in it ; but it contained numerous remains
of plants, partly in a state of decomposition, but still exhibiting a
green colour, and globules of starch in the cells, likewise brown and
white feathers, fragments of egg-shells and fish-bones. The aqueous
solution was of a light reddish-brown colour, was strongly ammonia-
cal, and deposited on slow evaporation an abundant crop of crystals
of the triple phosphate of ammonia and magnesia. On adding nitric
acid to the filtered liquid, an abundant flocculent brown precipitate
subsided, which consisted of humic acid and extractive. The inso-
luble portion was of a light sandy-yellow colour.

On boiling with solution of potash and precipitation of the filtered
solution with hydrochloric acid, a light brown flocculent substance
subsided, which amounted to 5*50 per cent. This was first regarded
as uric acid, but on further examination it proved to contain but
slight traces of that ingredient, and to consist of a substance
allied to humic acid.

To determine the absolute amount of ammonia, one of the ingre-
dients on which the value of guano chiefly depends, a weighed por-
tion of the guano in its normal state was analysed according to the
method described by Varrentrap and Will, and afforded 9*70 per cent.

The other ingredients were determined in the usual way, and ac-
cording to the results of analysis 100 parts of the guano* in question
consist of —

* While drawing up this article for publication, we received from a friend a

472 Intelligence and Miscellaneous Articles.

Volatile salts, as oxalate of ammonia, chloride of ammo-
nium, carbonate of ammonia, and combustible or-
ganic matter, containing 5'50 per cent, humic acid,

uric acid and extractive, and 9*70 ammonia 4-2,59

Water 27'13

Phosphates of lime and magnesia 22*39

Insoluble residue in nitric acid, consisting of sand. . . . 0'8l
Alkaline salts, chiefly phosphates, muriates, and small

quantity of sulphates (chiefly potash) 7*08

100-00
From the above examination, it is evident that the African guano
differs considerably from the Peruvian and Chilian, i. e. that it has
been more exposed to the decomposing influences of atmosphere
and water than either of those kinds, and tends rather to confirm
the views of Fritzsche, Payen and Boussingault, Girardin and Bi-
dard, that the Peruvian guano is in a state of fossilization.

The most remarkable guano hitherto analysed is that described
by Fritzsche*, whose investigations, as far as we are aware, have
hitherto remained unnoticed in this country. We need therefore
not apologize for giving a brief abstract of them in this place, more
particularly as they will prove how requisite it is that the agricultu-
rist, before purchasing guano, should have a sample submitted to
analysis by some competent chemist. Fritzsche describes the guano
submitted by him to examination as a dry coarse powder, in which
some large compact masses occurred of a yellowish-brown colour.
The compact pieces from which the powder had originated were
distinctly composed of superposed strata, seldom horizontal, but
most frequently compressed and undulate. The strata are of two
kinds, one of a brownish-yellow colour, and consisting principally of
urate of ammonia; the other of a blackish-gray or dark brown
colour, and formed principally of clay. Both layers alternate with
each other irregularly, their relative proportions varying consider-
ably. The argillaceous strata are of a more compact nature than
those of the urate of ammonia. All the layers of clay are coated
with a whitish rind, which cannot be readily washed off with water.
This coating consists of urate of ammonia, and proves beyond a
doubt that the guano in question has acquired its present state
through the agency of water. Feathers, vertebra? and fragments of

circular containing an analysis by Dr. Ure of some guano imported by the same

vessel, the results of which we subjoin : —

Decayed combustible animal matter, containing 3 parts of uric acid... 37'0
Ammonia, chiefly combined with phosphoric acid, only four-tenths

being in the state of carbonate 9-5

Earthy phosphates, as above 18*5

Siliceous earth 0*5

Fixed alkaline salts, a good deal of potash salts 6"0

Water or moisture 28-5

These results agree as closely as could be expected in such an heterogeneous

mixture.
* Bulletin de VAcad. de Petersburg, I. No. 6.

Intelligence and Miscellaneous Articles* 473

other fish-bones occur frequently, as well as remains of plants and
some seed.

The guano had a strong urinous smell and a faintly saline taste.
16 oz. of the pulverulent mass in its moist state afforded on solution
in caustic potash and precipitation with muriatic acid, 7 oz. 2 drms.
of a yellowish-brown coloured crystalline hydrate of uric acid
= 37 per cent, anhydrous uric acid.

200 grs. of a compact fragment with very few seams of clay, gave,
on being similarly treated, 118 grs. or 59 per cent, of anhydrous
uric acid. The residue of these experiments consisted for the
greater part of clay, which readily subsided, probably on account of
the earthy phosphates contained in it.

From the occurrence of so few organic remains, and from the in-
terposition of the argillaceous masses between the layers of urate of
ammonia, it is evident that the guano in question cannot have been
deposited by the birds in the state in which it occurs at present ;
the coating of urate of ammonia, which adheres so firmly to the
seams of clay, decidedly shows that water must have acted some part
at the formation of this deposit.

Let us suppose a clayey shore, which is flooded at high tide and
left dry at ebb, and behind it a lake to which the tide rises, and
flocks of sea-birds which visit the coast at the time of low water ;
all the requisite conditions are given. Fish and other marine ani-
mals, left by the tide, attract the birds, which, in taking their food,
at the same time loosen the soil. Meantime a tropical sun dries and
breaks up the soil ; the tide returns, and carries these loose masses
of clay, and the excrements deposited on them, into the basin. In
their progress a process of lixiviation takes place ; the lighter organic
remains, which have not time to subside, are carried away by the
effluent water, while the heavier urate of ammonia and fragments of
clay subside. At some depth the bottom of the basin is not disturbed
by the flood, and here a solution of urate of ammonia may be formed,
which subsequently, on drying, covers the layers of clay with a
white coating, and serves to unite the pulverulent urate of ammonia
and loose clay. The amount of soluble constituents in the guano
(20 per cent.) is not opposed to this view, for if the urine of these
birds is secreted, like that of serpents, in a concrete form (containing
therefore solid urate of ammonia), it would be impossible for the
salt water to deprive it of much of its soluble constituents during
its transfer, and its rapid subsidence in the basin would prevent sub-
sequent extraction.

Now it is quite evident that the African guano has been exposed
to entirely different conditions to that of the Peruvian just described ;
for while this contains the enormous amount of 59 per cent, uric
acid, scarcely traces of it occur in the former, it having undergone
total decomposition. Moreover, the amount of soluble constituents
in the African guano (above 60 per cent.) entirely excludes all idea
of its having been subjected to any such lixiviating process as that
supposed by Dr. Fritzsche.

We may, in conclusion, venture a few words with respect to the

474 Intelligence and Miscellaneous Articles.

comparative value of the African guano as a manure. This depends,
first, on the amount of phosphates, and secondly, on that of the am-
monia, or substances capable of affording that ingredient. But it is
also evident that the state in which the nitrogenous compounds are
contained in the manure must be of some importance, i. e. whether
they exist in the form of ammonia, as is the case with the guano
submitted by us to analysis, or in the state of uric acid %

It is probable that this African guano would prove extremely
stimulating to vegetation at first, but that its power would soon be
spent, unless previous to its employment it were mixed with some
substance capable of fixing the ammonia, such as gypsum or char-
coal, as recommended by Boussingault and Payen ; while that con-
taining uric acid would, from the slow decomposition of this sub-
stance, prove for a long time a constant source of nitrogen propor-
tionate to the growth of the plants. — CJiem. Gazette, May 1, 1844.

PROCESS FOR OBTAINING IRIDIUM. BY M. E. FREMY.

In order to obtain iridium, M. Fremy treats the chloride of iri-
dium with hydrochlorate of ammonia ; a precipitate of a brownish-
red colour is formed, which is a compound of the bichlorides of iri-
dium and osmium with hydrochlorate of ammonia ; in order to sepa-
rate these a current of sulphurous acid is passed into the two salts
suspended in water, by this the iridium is dissolved, and the osmium
remains precipitated in the state of a red salt. The soluble salt of
iridium thus obtained crystallizes in large brown prisms from solu-
tion in hydrochlorate of ammonia ; when it is calcined in a current
of hydrogen, it yields pure iridium, which retains the crystalline form
of the salt.

The soluble salt of iridium, under the influence of chlorine, repro-
duces the black insoluble salt, and serves for the preparation of all the
compounds of iridium. — Journ. de Ph. et de Ch., Mars 1844.

AN EXPERIMENT FOR RENDERING APPARENT THE ADJUSTING
POWER OF THE EYE. BY REUBEN PHILLIPS.
If the head be turned away from a window, and if a small bright
piece of metal, as a knitting-needle, be held within a few inches of
the eye, so that the needle may be distinctly seen, taking care so to
place the head as to intercept as little as possible of the light which
can fall on the needle ; — things being thus arranged, if the eye be
directed to a wall, a few feet distant, for a few seconds, and then,

* " The value of a manure depends therefore on the proportion of nitrogenized
organic matter, and especially in relation to the non-nitrogenous organic sub-
stances, and lastly, on the decomposition of the quaternary substances being gra-
dually effected, and so keeping pace with the progress of vegetation." And again,
" A manure entirely decomposable into its soluble and gaseous products in the
course of a single year will be capable of producing as great an effect on the first
crop as five times the quantity of another manure which would require five years
for its ultimate decomposition, but then the latter will furnish useful products
during a period five times longer." — Payen and Boussingault in Ann. de Chim.
et de Phys., t. iii. pp. 67 and 70.

Intelligence and Miscellaneous Articles. 475

if the attention be momentarily directed to the appearance of the
needle, its outline is seen to be indistinct, and those parts which re-
flect most light are seen with luminous protuberances, exhibiting all
the appearances of light imperfectly focalized on the retina. If the
eye be kept directed to the needle for but a very short time (accom-
panied perhaps by an effort to see distinctly), the ill-defined image
rapidly contracts to perfect vision.
Topsham, near Exeter, March 4, 1844.

DOUBLE CARBONATE OF AMMONIA AND MAGNESIA.
BY M. P. A FAVRE.

This salt may be obtained in several modes ; by agitating carbo-
nate of magnesia in a solution of carbonate of ammonia and filtra-
tion, the solution rapidly deposits crystals on the sides of the vessel
containing it, and these are right rectangular prisms ; when they are
collected and spread on filtering paper, they dry rapidly ; after being
inclosed in a bottle, when perfectly dry, they did not yield any am-
moniacal odour, on opening the bottle several days afterwards.

The portion remaining on the filter, again submitted to similar
treatment, yielded a solution which afforded more crystals, and even-
tually it altogether assumed a granular aspect, and became entirely
the salt in question, of which large quantities may be thus obtained.
The analyses which were made of this salt were performed upon
crystals which were deposited from the filtered liquor, and not those
which granulated.

Another method for obtaining large quantities of these crystals,
and in a very pure state, consists in mixing a saturated solution of
bicarbonate of magnesia with one of carbonate of ammonia; the
double carbonate of magnesia, being very slightly soluble, notwith-
standing a great excess of carbonate of ammonia, but few crystals
are obtained by the first method above described ; whereas the bicar-
bonate of magnesia being more soluble, brilliant and well-defined
crystals of the double carbonate are obtained in a few seconds after
it is mixed with the solution of carbonate of ammonia.

This salt in fine prismatic crystals yielded by analysis as under : —

Magnesia 15-77 1592 158

Carbonic acid . . 34-90 35*00

Hydrogen 6-70

Azote 11-60

Oxygen 31-03

100*
These analyses indicate the annexed formula :

(CO2, MgO, C03H4AzO, 4HO), '
which gives the following numbers : —

Magnesia 16*28

Carbonic acid .... 34*70

Hydrogen 6*31

Azote 11*17

Oxygen 31*54

100*

476 Intelligence and Miscellaneous Articles.

This salt is unalterable by exposure to the air ; when treated with
cold water the crystals lose their transparency, but nearly retain their
form. — Ann. de Ch. et de Phys., Avril 1844.

ON THE IDENTITY OF SCORODITE AND NEOCTESE.

9tq I

BY M. DAMOUR.

M. Descloizeau having found that these substances agreed per-
fectly in their primary form, viz. a right rhombic prism, and in the
various modifications to which it is subject, M. Damour undertook a
fresh analysis of them, that of Berzelius not agreeing with the pre-
vious one of Ficinus. For this purpose crystals of scorodite from
Vaulry (Haute Vienne), from Saxony and Cornwall, and of the
neoctese of Brazil, from the collection of the Ecole des Mines, were
examined.

The specific gravity of scorodite of Vautry was found to be 3*11,
and that of the neoctese of Brazil 3- 18 ; when heated in a tube both
of them yielded water, which did not alter litmus paper ; the residual
matter was opake and of a grayish-yellow colour ; no arsenious acid
sublimed when pure crystals were operated on ; before the blowpipe
both substances swell up and are reduced to blackish-gray globules ;
on charcoal they yield arsenical odour, and a black scoria which
obeys the magnet. Nitric acid, whether hot or cold, does not act
upon scorodite or neoctese, but hydrochloric acid readily dissolves
them, and the solution is of a brown colour ; this is decomposed by
ammonia, partially ; the precipitate formed is of a brown colour.

The powder of these minerals when placed on a fragment of caustic
potash, instantly assumes a rust colour, without any admixture of
blackness ; the hydrochloric solution, mixed with the chloride of
sodium and gold, gives no trace of reduced gold. These experiments
prove that the minerals in question are of the same nature, and that
the oxide of iron which they contain is the peroxide ; in order to de-
termine the proportions of the constituents of these minerals the fol-
lowing experiments were performed : —

The mineral, reduced to powder and dried in vacuo at the usual
temperature, was dissolved, with heat, in concentrated hydrochloric
acid ; the solution took place rapidly. The liquor was diluted with
water and dropped gradually into a phial containing ammonia and
hydrosulphate of ammonia. The mixture was digested at a tempe-
rature of 122° to 140° Fahr., and at the expiration of twenty-four
hours, the precipitated sulphuret of iron formed was collected on a
filter and properly washed (A.). The sulphuret of iron, while moist,
was dissolved in aqua regia, and then precipitated by means of am-
monia ; the liquor (A.) separated from the sulphuret of iron was
rendered slightly acid by acetic acid, and after some time yellow
sulphuret of arsenic was precipitated ; in order to ascertain the pro-
portion of arsenic which it contained, this sulphuret, previously dried
in vacuo, was acted on by aqua regia ; globules of sulphur remained,
which were collected and weighed ; the acid liquor contained arsenic
and a little sulphuric acid formed from the sulphur, the quantity of

Intelligence and Miscellaneous Articles- 477

■a

which last was determined by means of chloride of barium, and added
to that of the sulphur previously obtained ; by subtracting the weight
of the sulphur from that of the sulphuret of arsenic, the difference
gave the weight of the arsenic, which by calculation indicated that of
the arsenic acid contained in the mineral. , {TVfqni -»ht mo

The water was separately determined by heating the mineral pre-
viously dried in vacuo in a platina crucible ; the loss of weight deter-
mining that of the water.

Four analyses gave the following as the constituents of the mine-
rals from the places named : — 1. Scorodite in small greenish crystals
from Vaulry ; 2. scorodite in bluish crystals from Cornwall; 3.
bluish scorodite, on the surface of altered arsenical pyrites from Sax-
ony ; 4. neoctese in bluish transparent crystals from Brazil,
orfjjlo nor jj# III. S/JI ^iy.

Arsenic acid ... . 5095 51-06 52-16 50-96

-il{Peroxide of iron.. 31-89 32'74 33-00 33-20

Water 15-64 15-68 15-58 15-70

98^48 g^is foo-Ti WM

It appears therefore that both these minerals consist of -^fljjit
One equivalent of arsenic acid .. 58-00 50*00

One ... peroxide of iron 40-00 34*48

Two ... water 18-QO 15-52

Equivalent ,yi Jvd .116* 100'

M. Boussingault found that an arseniate of iron, occurring as an
earthy mass at Marmato, province of Popayan, yielded the following
substances :•—

afajs \a& "Arsenic acid . $Vi\ ,A W&ifp&X"'"**'*01 »«a«toq
Peroxide of iron ! . ; .' 34'3

Oxide of lead 00-4

Water 16-9

"fOl-2 01* *° 9^x0 ox**
The composition of this substance agrees therefore perfectly with
that of scorodite ; the following are the results of Berzelius's analysis
of neoctese, which agree very nearly with all those above given, and
evince the propriety of M. Damour's suggestion, that the name of
neoctese should be abandoned and that of scorodite only retained : —

Arsenic acid 50-78

Peroxide of iron 34-85

Water 1555

Arseniate of alumina 0-67

Phosphoric acid and oxide of copper . . traces

101-85
Ann. de Ch. et de Phys., Avril 1844.

COMPARATIVE ANALYSIS OF ANATASE AND RUT1LE.
BY M. D AMOUR.

The author observes, that it is well known that anatase crystallizes
in acute octahedrons, and that it cleaves parallel to the faces ; it

478 Intelligence and Miscellaneous Articles.

scratches glass and is scratched by quartz and rutile. Its specific
gravity is 3*857, that of the rutile being 4*209 ; it is infusible by the
blowpipe ; when strongly heated with the phosphorus salt on a cupel,
it dissolves completely, and gives in the reducing flame a bluish-violet
glass, perfectly similar to that obtained by rutile ; this colour disap-
pears in the oxidating flame, but it returns if a globule of tin be added
to the fused mass.

When reduced to powder, anatase is not acted upon either by nitric
or hydrochloric acid ; boiling sulphuric acid partially dissolves it ; of
one part so treated 0*1918 were dissolved. The insoluble portion
was not altered in colour, and gave the same reaction with the salt
of phosphorus as it did before treatment with the acid ; the dissolved
portion gave by evaporating the acid a white gummy mass, which
decrepitated strongly when attempts were made to heat it to redness.
It consisted of sulphate of titanium, and gave with the salt of phos-
phorus the same reaction as the matter unacted upon.

A comparative examination having been made in the same way
on the rutile of Saint- Yrieix, results almost identical were obtained ;
rather less was dissolved by sulphuric acid.

In order to analyse anatase it was reduced to very fine powder,
and fused with eight times its weight of recently prepared bisulphate
of soda ; it was quickly and perfectly dissolved. The fused mass
was dissolved, when cold, in a large quantity of hot water, and a
current of sulphuretted hydrogen was passed into the acid solution ;
after some time a small quantity of brown flocculi was deposited,
consisting principally of sulphur; these were volatilized by heat,
leaving a slight residue, which Was found to be oxide of tin.

The solution was afterwards heated in order to expel the excess
of sulphuretted hydrogen, and then filtered ; a small portion of hy-
drochloric acid was added to it, and then sulphite of ammonia suf-
ficient to saturate the excess of acid ; sulphurous acid was expelled,
and the liquor, when heated, deposited a white flocky precipitate in
considerable quantity ; this collected on a filter was readily washed.
After calcination it was white with a tint of yellow, and had a shi-
ning greasy lustre. By fusing with the salt of phosphorus it evinced
the properties of titanic acid.

The liquor from which this precipitate was separated, was satu-
rated with ammonia, and hydrosulphate of ammonia was afterwards
added to it ; sulphuret of iron containing a little titanic acid was se-
parated; the sulphuret was collected and dissolved in nitric acid,
and the solution of iron, separated from the titanic acid which the
sulphuret of iron contained, was supersaturated with ammonia, and
the peroxide of iron precipitated was collected and weighed.

The liquor separated from the sulphuret of iron was not rendered
turbid, either by oxalate of ammonia or phosphate of soda.

One hundred parts of anatase yielded

Titanic acid 98*36

Peroxide of iron . . I'll

Oxide of tin 0*20

99*67

Meteorological Observations. 479

It results from this analysis that anatase consists almost entirely
of titanic acid ; if it were composed of the blue oxide of titanium, an
increase of weight should have been obtained by its oxidizement ;
but, notwithstanding the precautions employed to avoid all loss, the
results of the analysis always amounted to less than the substance
employed, which induced M. Damour to suppose that he has not
committed any error in estimating the titanium in anatase to be at
the maximum of oxidation.

Rutile from Saint- Yrieix in semi-transparent reddish crystals,
cleavable according to the faces of a rectangular prism, was analysed
in the same method, and yielded

Titanic acid 97*60

Peroxide of iron .. 1*55

99-15
M. Damour concludes from his experiments that there is no dif-
ference in the composition of anatase and rutile. — Ann. de Ch. et de
Phys., Avril 1844.

METEOROLOGICAL OBSERVATIONS FOR APRIL 1844.
Chiswick. — April I. Foggy: dry haze: clear. 2 — 4. Very fine : clear and dry.
5, 6. Overcast : very fine : clear. 7. Clear and fine throughout. 8. Foggy :
clear and fine. 9. Fine: clear and dry. 10. Hot and very dry. 11. Fine.

12. Fine : rain at night. 13. Cloudy: rain. 14. Hazy: showery. 15. Hazy:
very fine. 16. Hazy: cloudy : clearandfine. 17. Foggy : very fine. 18. Cloudy
and fine. 19 — 24. Very fine. 25. Slight haze : very fine. 26. Dry haze. 27,

28. Clear and dry. 29. Fine: dry haze: cloudy. 30. Clear, with excessively
dry air. — Mean temperature of the month 3*44° above the average.

Boston. — April 1. Foggy. 2 — 4. Fine. 5. Fine : rain a.m. 6—8. Fine.
9. Cloudy. 10. Fine. 11,12. Fine: rain p.m. 13. Cloudy : rain p.m. 14.
Fine. 15. Cloudy. 16—19. Fine. 20, 21. Cloudy. 22—28. Fine. 29. Cloudy.
30. Fine.— N.B. This month has been extraordinarily dry and warm.

Sandwick Manse, Orkney. — April 1, 2. Cloudy : showers. 3. Bright : showers.
4. Cloudy. 5. Cloudy: rain. 6. Clear: cloudy. 7. Cloudy. 8. Bright: cloudy.
9. Clear: cloudy. 10. Cloudy. 11. Showers: clear. 12. Clear: cloudy.

13. Cloudy : rain. 14. Bright : cloudy. 15. Bright: showers. 16. Cloudy.
17, 18. Bright: showers. 1 9. Rain : cloudy. 20. Bright : cloudy. 21. Cloudy .

22. Cloudy: showers. 23. Cloudy: sleet-showers. 24. Bright: cloudy. 25.
Rain: fine. 26. Rain : showers. 27. Hail-showers : clear. 28. Bright: clear.

29. Clear. 30. Bright : clear.

Applegarth Manse, Dumfries-shire. — April 1. Fine. 2. Dull: rain p.m. 3.
Rain. 4. Fair, except one slight shower. 5. Rain. 6. Fine : hoar-frost. 7.
Fine. 8. Fine, but cloudy. 9. Wet a.m. : fine, 10. Fine. 11. Fine: one
slight shower. 12, 13. Rain. 14, 15. Wet. 16. Hoar-frost. 17. Fair:
rain p.m. 18,19. Fair. 20. Fair and fine. 21. Fine : one slight shower. 22,

23. Fine. 24. Shower early a.m. 25. Fair. 26. Fair : heavy dew. 27. Fair.
28, 29. Hoar-frost. 30. Fair and dry.

Mean temperature of the month 47°*2

Mean temperature of April 1843 46 "4

Mean temperature of spring water 50 '5

Mean temperature of ditto April 1843... 47 "0

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THE
LONDON, EDINBURGH and DUBLIN

PHILOSOPHICAL MAGAZINE

AND

JOURNAL OF SCIENCE.

SUPPLEMENT to VOL. XXIV. THIRD SERIES.

LXVII. Observations on the Entrance Passages in the Py-
ramids qfGizeh. By Sir John F. W. Herschel, Bart.,
F.R.S., with Introductory Remarks by Col. Howard Vyse*.
yV.S it had been supposed that the inclined passages were in-
•*■** tended for astronomical purposes, I mentioned the cir-
cumstance to Sir John Herschel, who with the utmost kind-
ness examined the annexed table, and entered into various
calculations to ascertain the fact. I also informed Sir John
of the allusion in the Quarterly Review to M. Caviglia's re-
marks respecting the polar star, and likewise of its having
been seen by Captains Irby and Mangles from the inclined
passage in the Great Pyramid at the period of its culminating,
on the night of 21st March 1817.

M. Caviglia's remarks, contained in a letter to Mr. Hamil-
ton, dated September 21st, 1818, are as follow: —

" Tous les chemins qu'il y a dans l'interieur de ce monu-
ment (la Grande Pyramide), ceux qui sont en pente, forment
un angle de 27° avec ceux qui sont en ligne horizontale.
Mais ce qui a merite mon attention est que Ton cesse de voir
Petoile polaire on avanfc qu'on eut bouche le chemin Ton
cessoit de descendre pour monter."

M. Caviglia no doubt could have seen the star from this
passage, but the manner in which he observed it is not clearly
described, nor can, after all, any conclusion be drawn from the
present length of the passage, either from the entrance to the
beginning of the ascending communication, or in any other
parts of it, because, owing to the dilapidated state of the ex-
terior of the pyramid, the top of the passage has lost twenty-
one feet six inches of its original length, and of course the
bottom proportionably more.

It would appear that the direction of the passage was de-
termined by the star, which was polar at the time when the
pyramid was constructed, and that the exact aspect of the

* Extracted from Col. Vyse's work, entitled " Operations carried on at
the Pyramids of Gizeh in 1837," vol. ii. p. 105.

Phil. Mag. S. 3. No. 162. Suppl. Vol. 2*. 2 I

482 Col. H. Vyse and Sir John F. W. Herschel on the

building was regulated by it; but for the reasons already stated,
it could not have been used for celestial observation. The
coincidence of the relative position of a Draconis with the sup-
posed date of the pyramid is at all events very remarkable.
A Table showing the exterior angles of the buildings, the incli-
nations and proportions of the inclined passages, and also
the dimensions of the sarcophagi, that have been found hi the
nine existing Pyramids at Gizeh*.

Passages.

Sarcophagi.

Pyramids.

Angle.

Length.

Height.

Breadth.

Height above
base.

Angle of
building.

Height.

Width.

ft.

in.

ft. in.

ft. in.

ft. in.

ft. in.

ft. in.

Great ...

26 41

320

10

3 11

3 5i

49 0

51 50

3 5

3 3

Second...

25 55

104

10

3 11

3 5i

37 8

52 20

3 0

3 6i

Third ...

26 2

104

0

3 111

3 5i

13 0

51 0

2 11

3 1

Fourth...

27 0

27

0

3 6

3 3

f without the \
I building. J

in steps.

2 7

2 7

Fifth ...

27 12

56

9

3 11*

3 5i

2 6

52 15

3 1|

3 3

Sixth ...

30 0

47

9

3 11

3 2

("without thel
I building. /

in steps.

No sarcophagus.

Seventh .

33 35

55

3

4 0

3 6

at the base.

52 10

Not found.

Eighth ...

34 5

37

0

4 0

3 6

8 9

52 10

Not found.

Ninth ...

28 0

53

0

3 11

3 5

2 6

52 10

Not found.

The base of the Great Pyramid was above high Nile, in
1837, 138 ft. 9 in.

The base of the Second is above the base of the Great Py-
ramid 33 ft. 2 in.

The base of the Third is above the base of the Great Pyra-
mid 41 ft. 7 in.

The base of the three pyramids, south of the Third, are lower
than the base of the Third 1 6 ft. 8 in.

The bases of the three pyramids east of the Great Pyramid,
appear to be on a level with it.

The Second Pyramid is about 400 ft. to the south of the
Great Pyramid.

The Third Pyramid is about 750 ft. to the south of the
Second.

Sir John HerscheVs Observations on the Entrance Passages in
the Pyramids of Gizeh.
Four thousand years ago the present polar star, a Ursa3

* The three pyramids of Abonseir are situated about seven miles to the
south-eastward from Gizeh, on a ridge about eighty feet above the plain.
The angle of building of the northern is 51° 35'; that of the descending
passage in the northern front 27° 5'. The angle of building of the middle
pyramid, and that of the entrance, could not be ascertained on account of
its dilapidated state. The angle of building of the southern pyramid was
not discovered, but that of the entrance was 26°.

Entrance Passages in the Pyramids of Gizeh. 483

Minoris, could by no possibility have been seen at any time
in the twenty-four hours through the gallery in the Great
Pyramid, on account of the precession of the equinoxes, which
at that time would have displaced every star in the heavens,
from its then apparent position on the sphere, by no less a
quantity than 55° 45' of longitude, and would have changed
all the relations of the constellations to the diurnal sphere.

The supposed date of the pyramid, 2123 years B.C., added
to our present date, 1839, form 3962 years (say 4000), and the
effect of the precession on the longitudes of the stars in that
interval having been to increase them all by the above-named
quantity, it will follow that the pole of the heavens at the
erection of the pyramid must have stood very near to the star
a Draconis, that is, 2° 51' 15" from it to the westward, as we
should now call it ; a, Draconis was therefore at that time the
polar star ; and as it is comparatively insignificant, and only
of the third magnitude, if so much*, it can scarcely be sup-
posed that it could have been seen in the daytime even in the
climate of Gizeh, or even from so dark a recess as the inclined
entrance of the Great Pyramid. A latitude, however, of 30°,
and a polar distance of the star in question of 2° 51' 15", would
bring it at its lower culmination to an altitude of 27° 91', and
therefore it would have been directly in view of an observer
stationed in the descending passage ; the opening of which, as
seen from a point sixty-three feet within, would, by calcula-
tion, subtend an angle of 7° 7', and even from the bottom,
near the sepulchral chamber, would still appear of at least 2°
in breadth. In short, speaking as in ordinary parlance, the
passage may be said to have been directly pointed at a Dra-
conis at its inferior culmination, at which moment its altitude
above the horizon of Gizeh (lat. 30°) would have been 27° 9',
refraction being neglected as too trifling (about 2') to affect
the question. The present polar star, a, Ursae Minoris, was at
that epoch 23° more or less in arc from the then pole of the
heavens, and of course, at its lower culmination, it was only
7° above the horizon of Gizeh. No other astronomical rela-
tion can be drawn from the table containing the angles and
dimensions of the passages, for although they all point within
five degrees of the pole of the heavens, they differ too much
and too irregularly to admit of any conclusions.

The exterior angles of the buildings are remarkably uni-
form, but the angle 52° is not connected with any astronomi-
cal fact, and was probably adopted for architectural reasons.

• In the Catalogue of the Astronomical Society, the magnitude of « Dra-
conis is stated as intermediate between the third and fourth. It is certainly
inferior to the third ; and it is to be observed, that there is not any larger
star near it, which could at that epoch have been preferred as a pole star.

2 I 2

484? On the Entrance Passages in the Pyramids of Gizeh.

Calculations.
Por. of a Draconis for 1839.

R.A. 1830 = 13h 59m 46s-6 Due 1830 = 65° 11' 26" (seeAstr.Soc.Cat.)
Precession + 9 years = + \4''6 Pre.+ 9years-=— 2 36

14 0 T2 65 8 50 = S for 1839.

Reduced to arc 210° 0' 18" = «

Precession in longitude for + 1 year, epoch 1800 , -f 50"*22350

Variation for 2000 years backwards, to obtain a mean rate \ _ n .(uqqr

of precession for 4000 J

+50 -17464

Multiply by years —4000

Precession in long. = -200697"*56 = — 55° 44' 57"*56 —200697*56000

or correctly enough for the purpose 55° 44' 58"

P the present place of the north

pole.
P' its place 4000 years ago.
a, the star cc Draconis.
0 its projection on the equinoctial.
rsi/3 = 210o0'18" = «

T £: = 180

rfi: /3 = 30 0 18 = angle

£ P«
In spherical triangle P II P'.
Given angle PnP= 55° 44' 58".
P II = P' n = obliquity of ecliptic
at a, mean epoch, 2000 years
back.
Obliquity ISOOy =23° 27' 55"
Var. for —20007 = + 1 31

23 29 26 — obliquity to be, and = Pn
Solution of triangle II PP'.
Sin | Pn P' — sin 27°52/29" ... 96698186 Tan 27° 52' 29"... 9*7233852

Sin obliquity 9*6005350 Cos obliquity ...99624319

Sin ^PP'=10°44/25'

Required 1st side PP'.

2nd angle P'P IT.

pn.

9-2703536

PP' = 21°28'50".
-vpn = 90o.
:fiP«=30o0,18"

Cotan64°7'22"... 9-6858171
Angle P'P n= 64° 7' 22"

« P n = 59 59 42
FPn = 64 7 22
P'P«= 4 7 40
CoE. 4° 7' 40" 9-9988720
Tan 21 28 50 9*5949652
Tana'2125 48 9-5938372"
24 51 10

In triangle P'P cc given PP' =21° 28' 50''

P«=24 51 10 =90-
Angle P 1 P cc = 4 7 40
Required a, P'.

Cos 21 28 50

Cos 2 25 22

Cos 21 25 48
CosP'« = 2 51 15

9-9687359
9-9996116
9*9683475
9*9688865
99994610

a" 2 25 22

Note. — These calculations, which take in all the influence
of the secular variations of precession, &c, may be considered
quite equal, in point of precision, to any direct observation
that an Egyptian astronomer of that date could have made.

[ 485 ]

LXVIII. Memorandum on Estuaries and their Tides.
By Sir H. T. De La Beche, F.R.S., F.G.S., $c*
T^HE existing state of any estuary, or tidal river, may be
considered as an adjustment, for the time, of certain con-
ditions, changes in any of which conditions effect alterations
in that state, productive of injury or benefit to the purposes
for which we employ, or may be desirous of employing, such
estuary, according to circumstances.

The action of the flood-tide in an estuary, or tidal river, is
to pond back, during its continuance, the river waters, which
would otherwise have flowed outwards for that time; so that
when the ebb-tide makes downwards, the tidal waters which
came up with the flood-tide are increased by the volume of
water so ponded back, independently of the ordinary dis-
charge of the river waters during the ebb.

The ebb-tide, therefore, is composed of the tidal waters
which came up with the flood, plus the water ponded back,
and the river water continuing to flow out during the ebb.

It follows that the mechanical effects produced on the bot-
tom of an estuary by the ebb-tide must be far greater than on
the flood, and that there is a constant tendency to force mud,
silt, sand and gravel outwards to the sea.

The mode in which these substances, commonly termed de-
tritus, are carried along is twofold: — 1st. When the move-
ment among the particles of water is sufficiently considerable,
the water will take up the detritus in mechanical suspension, as
it is termed, according to the amount of this movement ; that
is, the detritus is really lifted up and borne onwards actually
suspended in the water. 2ndly. The mud, silt, sand and gra-
vel, as the case may be, will be pushed or forced along upon
the bottom, according to the pressure and velocity of water
above them, producing the friction required.

It follows, where there are unequal velocities of waters in
tideways, that the same substances which may be mechanically
suspended in the water in one place, will be thrown down on
the bottom in another ; and that in situations where the water
remains for any sufficient time at rest, such places will be
gradually filled up by deposit of the substances mechanically
suspended in the water flowing into them.

In like manner also, substances which are pushed or shoved
onwards along the bottom by the weight and velocity of the
water above them in some situations, come to rest in others,
when such weight and velocity are sufficiently diminished.

As the volumes and velocities of tides in estuaries vary, and

* From the First Report of the Commissioners on Metropolis Improve-
ments, 1844 : Appendix, p. 205.

486 Sir H. T. De La Beche's Memorandum

the amount of water falling into them varies also, from the
comparatively small streams in dry weather to the heavy vo-
lumes discharged during freshets or floods, the mechanical
action on the bottom of the estuary is necessarily variable,
always allowing for a constantly prevailing action outwards ;
and unless there be sufficient compensating forces, general
changes will be effected according to those conditions which
are dominant.

As there is no sufficient force to counteract the discharge
of detritus outwards, this will accumulate in the estuary, if the
ebb-tide be not able to force it beyond into the sea.

The amount of detritus thrown into the estuary will depend
on the course of the river above it. If that course be rapid
to the tideway, and the water capable of forcing forwards gra-
vel, all minor detritus will be borne down, and the whole will
be discharged into the estuary, to be dealt with according to
its powers. And this is the general action in all kinds of river
courses, down to that which permits the river waters simply to
bear the matter of mud to the tideway, in which the velocities
may even be sometimes greater than in the river above.

The banks across rivers formed where detritus, either me-
chanically suspended or pushed onwards, is brought to rest,
from a discontinuance of the conditions necessary to suspend
or move it, and commonly known as bars, occur, as might be
expected, very variously in rivers. When arms of the sea,
gradually diminishing inland, terminate in estuaries, these bars
are often far up the tideway, where the rush of river waters in
a freshet is met by the quieting action of the tide ; in other
tidal rivers the bars occur at their embouchures, where the
action of the breakers not only tends to force the detritus back
upon the coast, but also stops the velocity of the estuary waters
discharged on the ebb.

In some situations, as in the sketch beneath, prevalent winds,
having action on the coast, force breakers along shore also
in a prevalent direction, A A, causing a beach, B B B, to
follow a line along shore, and across the mouth of the estuary ;
so that a formidable barrier to the discharge of the river-
borne detritus, seaward, by this and the other causes above
noticed, is presented, behind which shoals, C C C, accumu-
late, tending to fill up the lower part of the estuary, alluvial
flats forming above, D D.

From the action of breakers on a coast (a most powerful
action, throwing up shoals and bars at their embouchures),
combined with the loss of velocity of the estuary waters sea-
ward, depositing the detritus they can no longer transport or
push onwards, estuaries as a whole are filling up, some slower,

on Estuaries and their Tides.

487

some faster, according to conditions; a fact which, though
not always apparent in some places, during what have been

termed historical times, is abundantly shown in others, and,
when considered geologically, satisfactorily proved.

New channels may be formed from an increase of deposit
in one place, giving a new direction to the waters in another ;
and it is highly instructive to observe how an apparently very
small cause may produce important modifications and altera-
tions, changing the channels and shifting the banks or shoals ;
but the general resulting action is a Jilling-up, viewed as a
whole.

Such are the variable conditions existing in estuaries, and
so complicated are often the effects of the causes in action, that
it becomes of the utmost importance well to study and reflect
upon the value of each cause before we attempt changes in
connexion with an estuary intended for our advantage ; and
this more especially when a great commercial port is situated
on part of such estuary.

It will be obvious, if bridges traverse an estuary, that not
only will the piers stop the tide flowing upwards (in propor-
tion as the piers occupy the breadth of the river), thereby
bringing the head of the estuary more seaward, but that these
obstructions would tend to produce shoals in the bed of the
main channel ; for though the ebb, with its back-ponded river
waters, would pass between the piers with great velocity (be-
cause passing through what may be considered as a dam
pierced in many places), scooping out corresponding channels,
deposits would be formed in the eddies behind the piers, the
influences of which are prolonged into the main channel.

4-88 Sir H. T. De La Beche's Memorandum

It will also be readily seen, that when the strength of a tide
impinges on a bank (sufficiently hard to prevent its being worn
away), that any artificial alteration in the form of that bank
would produce a change in the direction of the tide, the shoal-
forming or channel-scooping influences of which will be felt
in proportion to the amount of change so made, due regard
being had as well to the new effects produced upon the flood
as upon the ebb-tide.

As, at any given time, the forms of natural banks in estuaries
are but adjustments to the general conditions existing at that
time, it follows that, if these forms be artificially altered, this
adjustment is destroyed, and a new state of things arises,
which may be considered local or otherwise, according to the
amount of change. In strictness, viewing an estuary as a
whole, and the effects produced by changes of this kind upon
the two tides, that which may appear of very little importance
should be considered as, to a certain extent, producing gene-
ral results.

As the velocity of equal volumes of water in rivers depends
on the amount of fall of their channels or courses, and as the
same necessarily holds good in estuaries, to that level which
may be considered as low water (when such is not outside, the
whole estuary being above real low water on the coast), the
fall of the channel of the estuary from its head to this level,
all other things being equal, gives the general velocity of the
waters of the ebb-tide ; whence it follows that whatever scour
or mechanical action of the water on the bottom may be due
to the influence of this fall, it cannot be altered, as a whole,
so long as these two points remain at the same distance from
each other, and the difference of their levels is constant, equal
volumes of water being understood.

Let, in the annexed sketch, the line D A B C represent,

at an exaggerated angle, the bottom of part of a river, above
an estuary, the bottom of the estuary itself, and a portion of
the sea bed ; the line G A being that of high water in the
estuary, and E B that of low water ; and let A B be the bot-
tom of the estuary, and B C a part of the sea bed beyond it.
So long as A, the head of the estuary, and B, the level of low
water, remain at the same distance, and at the same difference
of level, and the volume of water passing down, or rather the
excess of influence of the ebb-tide over the flood, viewed as a

on Estuaries and their Tides, 489

whole, be a constant, any deepening of the bed of any part of
the estuary, as for instance at H I, will, it is* obvious, not
alter the amount of the general slope from A to B ; for the in-
fluence of any extra water lodged in the cavity H I, so long
as H retained its height, supported by the bottom HBC,
would be nothing as to scour of the bed, since it would merely
constitute a pond or pool in the general channel, that would
be again filled up by detritus brought down from above, in the
usual way, along the bottom D A I.

Assuming that the action of the tidal water introduced at
the flood-tide is as great upon the bed of an estuary as during
the ebb, the same volume of water, viewing only the tidal
water, passing in and out, — an assumption not strictly correct,
inasmuch as the flood-tide flows up an inclined plane, and the
ebb runs down it, — but, for convenience, assuming this action
to be equal, we should anticipate that when the back-ponded
river water can be let loose upon the ebb, the greatest scour-
ing effects outwards would be when the volume and velocity of
the united waters, viewed in combination, should be the great-
est, and that that would be not immediately after high water,
when the pressure of the supporting tide is slowly removed,
but towards the middle of the tide, when (though the volume
was greatest nearer high water) the velocity was so much in-
creased, as, with the volume of water still remaining, to pro-
duce the greatest effects. This anticipation is borne out by
observation, which appears to show that from about two to
four hours' ebb the greatest scour of the estuary bed is ef-
fected.

All observation tends to show, that the greater the volume
of tidal water coming up an estuary with the flood, the greater
is its mechanical or scouring action when its volume and ve-
locity are increased by the addition of the ponded back river
water, and the ordinary river discharge. And it should be
borne in mind, that it is only during the ebb that the river
water passes out as a whole, though in some estuaries, during
heavy freshets, the river water, from its less specific gravity,
has been known to run downwards on the top of the flood,
coming upwards : proved by large vessels, such as men-of-
war, drawing several feet of water, riding at anchor with their
heads to the first of the flood-tide, while boats alongside, draw-
ing little water, laid with their heads up stream against the
freshets. It may be here observed, that when conditions are
favourable, the flood-tide running in lifts the outgoing ebb,
particularly when composed of little else than river water, in a
wedge-like manner : from this, to the conditions where the
flood suddenly overcomes the ebb-tide by a great wave, or
bore, as it is termed, there are various modifications.

490 Sir H. T. De La Beche on Estuaries and their Tides.

Much mischief has been found to be occasioned in estuaries
by embanking, producing sensible effects even when portions
only covered at spring-tides have been taken for agricultural
purposes. When it is considered that the weight, for friction
purposes, arising from volume of water combined with the re-
quisite velocity, causes any given amount of scour or mecha-
nical action on the bed of an estuary, it follows, that if we stop
out the tide, diminishing the volume of water, even supposing,
for convenience, that the velocity remained the same, which
would not be the case, the scour or mechanical action cannot
be the same as previously, and that, this action being dimi-
nished, detritus which would have been swept onwards under
the former conditions would now remain and accumulate.

It may be here observed, that, in estimating the power of
the combined action of volume and velocity of water to produce
scour or mechanical effects on the bottom of an estuary, great
care should be taken to ascertain the real velocity where the
waters come into contact with such bottom, shoving and push-
ing detritus onwards, otherwise very erroneous inferences may
be drawn. Certain mechanical effects are considered to be
produced by the action of given velocities of water. Without
entering upon the question of how far the experiments made
may appear to justify the conclusions drawn, it will be obvious
that, whatever action may be due to the velocity of water alone,
if the velocities on the surface of the main stream of tide at
certain times are only known, and those at the bottom, from
considerable friction, are much less, calculations as to scour,
founded on the surface velocities (those usually alone known
to mariners and others engaged in the navigation of estuaries),
cannot be accurate.

Although much injury would be occasioned by stopping
out the entrance of effective tidal waters in estuaries by em-
bankments, it does not follow that judicious arrangements
may not be made with them, so that one greatly improved
general course may be obtained for the waters, and a main
channel formed of increased value for the purposes of naviga-
tion ; the loss of water occasioned in one place being compen-
sated by contrivances for allowing a greater volume to come
into another, so that the total effective water remains the same ;
a provision usually considered when improvements in estuaries
are under investigation.

Again, upon the principle of letting out a volume of water
to scour when it can have the greatest useful velocity, and pro-
duce the greatest mechanical effects on the bottom, — a prin-
ciple, however, which requires great care and consideration in
its application when the channels to be scoured are long, —
waters may be retained behind embankments employed for

The Rev. Brice Bronwin on some Definite Integrals. 491

giving a general direction to the main channel, and used for
roads, or otherwise, until the most favourable time of tide,
then to be thrown into the main stream, so that the volume of
ebb waters may even be larger at that time than prior to any
embanking on the river.

These are, however, subjects requiring great local care and
study, and are merely mentioned to show that artificial im-
provements could readily be made in estuaries without dimi-
nishing the effective action of tidal waters, if these be so ma-
naged, and the general arrangement such, that their useful
powers be not deteriorated.

June 10th, 1843.

LXIX. On some Definite Integrals.
By the Rev. Brice Bronwin*.

rr,HIS paper contains an easy method of obtaining some de-
A finite integrals. They are taken between the limits x = 0
and x= oo ; m and n are positive integers; P (n) = 1 . 2 . 3...w;
and Az = 2 ; also i = 0, 1, 2, &c.

/*. fsmx\m , x „. ,
Let yzm =J d x \—^r) cos \z x) J {x) 5

then Ti< = -*Jd*\—) cos(z + 1)^/W

- \fdx Cir)" cos {z - 1)a?/w = t A -^~-\ ;

therefore yz = ~ Afdzy2-1, = — &m f™ d zm yz~m \

or

fdxi J cos{zx)f{x) = ~AmJ d zm/dxcos(z —m)xf(x).

Differentiating 2 i times for 2, and making n = m — 2 i, there
results

f—p\nx)mcos{zx)f(x) = ~^ Anlfnd znJdxcos(z - ot)^*). (A.)

The integrations relative to % will introduce the corrections
C (z - mf-1 + C1{z- m)n~2 + &c, where Cv C2, &c. will
be infinite; but it will be easy to perceive that Aw_1 will
render them finite, and therefore Am will make them zero.

Makey(.r) = c~iX ; then J dxc~txcosrx = -% ^,

* Communicated by the Author.

492 The Rev. Brice Bronwin on some Definite Integrals.

/» edrn rn-\ r
T~, — s = d7 TT tan h e F (r, e).
s2 + rl P(n — 1) s v '

To abridge, let tan-1 — == 6r. If t = 0, 0,. = — - or — ,

according as r is positive or negative. Putting therefore z — m
for r, we have

/([x i |.y

B\xt^Am {z-m)n~l = 0; if we add it to ^m{(z-m)n'HZmmtn}
it will destroy the terms where 9 is negative, and give

^{{z-my-Hz_n}

=J(z + m)n-l-™(z + m-2)n 'l+m(™~% + m-4)H-l-bc\(a.)

the series continued till we arrive at powers of negative quan-
tities, which is always to be understood of similar series.
Let if denote the first member of (1.). It is evident that

Jm,n v '

when z = or > m, or when z = or z_ (—m). if = 0. This

function is of such a nature that we may change s into — z
without altering its value. Thus instead of (a.),, we may
employ, for the most part with great advantage,

Am{(z-m)n-1$z_m} =7rj(m-z)K-1 -^(w-z-2)""1 + &c.i. . {b.)

In fact we might have subtracted — Am(z — m)n~ l = 0 instead

ofaddingit,and reserved only the terms where 0 is negative; and
since m and n are both odd or both even, we may change the
last term of Am{(z — m)n~l 8z_m}, which is ±{z—m)n-1 Q%_m
into + (m— z)n~l Qm-.zi and the preceding ones in like manner.
Hence we obtain (b.). This will give immediately

/ -^ (s\n x)m cos (m - 1) x = ^~ » • • (2.)

' xn v ' v ; 2m V(n — 1)

Make in this last m and n = 1, 2, 3, &c; multiply the results
by 1, /z, h% &c, and summing to infinity, we have

//sin x\ q* — h*sm*x _ (A 1 \

^V~/^-/^sin2* + A2sin2x-7rV2 " ¥/' (3,)
Makew=l, ro=l, 3, 5, &c. ; multiply the results by 1,

— , — , &c, and sum

The Rev. Brice Bronwin on some Definite Integrals. 493

fax fcE£ \ Z{l-2£sin2^cos2x + £2sm4#}=7rZ(l+^.(4..)

k A3
Make n = 2, m — 2, 4, &c. ; multiply results by — , — — ,

hb

— , &c, and sum

o

/dx /sin.r\ ,/ hsmlx \ it , /2 + h\ ,- x

T \nr) tan Vi - y 8in« J = ¥ * V^j- (5-)

We might derive others, and we may derive many more
from (b) very simply expressed, as

/dx ( — l)iv
— (sin x)m cos (m - 2) x = ZOTTT, C*« (6-)
xn v ■ v 7 2w_n+1P(rc — 1)

and from all thus derived we may find others by summa-
tion.

If in (A.) we change f(x) into xf(x), we must not carry
the operations denoted by d and A so far by one step, or the
differential for z at the limit might not be zero. Thus the
second member of (A.) becomes

iZJl £tn- 1 j d zn- 1 J d x sm x COS (z ~ VI + 1 ) xf{x)

--~ &m-lJ*n d zn~ lJd x sin {z-~m + 2) xf(x)

.. '""^ Am~lf dzn~l fdxsin(z — m)xf(x)

=(~^' Am /" dzn~l /dxsin(z— m)xf(x);
and (A.) becomes
/ — (sin x)m cos (zx)f{x)

i ,_i r,(B,)

= Lnil Am / d zn~ l /dx sin (z — w) */(*)
2W %J *J

Here * sa t» — (2 i + 1). Make/(.r) = c~6*, and
J dxc~ xx sin rx—^—s, Cdxsinrx =. — ,

pn-\drn-\ rn-2 ] 1 1

But as A™rw-2 = 0, we may leave out the term containing A,
and we may change Ir into — lr*. Putting z — m for r, and

494 The Rev. Brice Bronwin on some Definite Integrals.
changing n into n + 1, we find

/*— *(siiuc)mcos«ar= }~ l )l Am{(z-m)n-H(z- mf}. (7.)

U xnK ' 2m+1P(«— 1)

The second member of this will not allow us to express
particular examples so simply as when n = m —2 i, nor perhaps
can we apply summation.

/*dx ...
Let t? = / - — (sin x)m sins x\ we easily find that 2y*

>n *J X Jm,n

= A.vm_1>n; and therefore by (1.),

A-<-1i,»°gw-(ip^,1)A»{(g-m)-1gz_w}.

Integrating and changing a into z + 1, m into ?w + 1, there
results

•fcj = 2-K-d Ara {(s " M)"_l ,*--) + c-

But as one of the quantities m and n must be odd and the
other even, the last half of the terms of AOT ( — m)n~1 will reduce
to the first, and therefore the last half of A™ {(— m)n~l S_m}
to the first with a contrary sign. Consequently

C= j"1*' ■ Am {(-m)"-1 Q_J = o.

2mP(n-l) v '

Hence
f% (^n *y sin ** = J~^_ {) A» { («-»)- 1 fl,..,}. (C)

By adding and subtracting -J- Am («— m)"-^ Am( -w)n_1
in this case,

The last term or correction is zero, except when m = n — 1, as
it may in this case be. We may here also change x into
(—2), then

where n—rn—- (2z — 1). If s = or > tw, or if z— or Z_ (— 7w),

vz =0.

As particular examples, m > w — 1 ;

The Rev. Brice Bronwin on some Definite Integrals. 495

J - (sin*)" sm (m - 1) x = - 2>.p(n-1). • (8.)

h3
Make w = 1, m = 2, 4, &c. ; multiply results by h, — , &c,

3

and sum

/», /sin ,r\ , / 2 /* sin2 a; \ , ^

dx {-—) tan-' ^ _yiin. J = *tan-' -. . (9.)

A3
Let n and ;« be as before, and multiply by h, — — , &c, and

9

sum

Let n — 2, w = 3, 5, &c. ; multiply by h, A2, &c, and sum

/dx /sin x\ h sin2 x sin 2 x ■■•» A . .

~r~ V a- / ] — 2 A sin2 # cos 2 .r + A2 sin4 x — ~2~ T+li * *'

Examples here might be greatly multiplied.
From (7.) we obtain

Integrating, and changing 2 into s 4- 1, m into m + 1,

&„ - a.+ipff-i) A" {(»-^)""! ^(»-»»)a> + c-

But as n=m — 2 f, C is easily shown to be zero. Therefore

/dx .
—r (s\n x)m sm % x

= 2"+'P(»-l)A"{'Z-'")""','Z-B')2}- J

cos(z+l).r cos(z — l).r

Since 2 cos # .r = s - h s * — ,

cos x cos .r

2 / ~"77 (sin .r)™ cos * # = / — r (sin x)m ' '—

J xn N *J xn cos #

/^.r . cos (.?— l)x

— (sn #)w — *„ ;
^w V ' cos X

or if

pdx , . . COS2T.T _ - ,4.1 ~_f

w* = / — (sin*)" , 2/ = if1^1 + u% l.

m>n J xn cos a; OT'W m'w w'w

Diminishing x by 2 successively till we arrive at

2y-% = u-%+l +u-%~\

Jm,n m,n m,n '

496 The Rev. Brice Bronwin on some Definite Integrals.
changing the signs of the alternate results, and adding, be-
cause u~z~l =wz+I, we have

,z+i -

js-2

*-4

^l=yz _«*-' + «*-*_ + y

,n Jm,n Jm,n Jm,n u

m,n

We suppose z an even integer. We may add and subtract

— v~z~ 2 + v~z~i — , &c. continued till they become zero.

Then putting for these quantities their values from (1.) and
(«.), there results

»?,»

_*_4)»-l + ,..}

n-1

;...,)

+ 2^4^{A(w-*-2r'1-^

(D

A=l, A,

1+y, As

m m(m — 1) 0

1+T+ iTs '&c*

If we make z + m =p + 2 1, the first series of (D.) may be

put under the form BA<pn-1 — B1Af-]j>M"1+ ••• ± ^t pn~l-
Expanding these differences, we find by comparison B = 1,
Bx = 2, B2 = 22, &c. The second series may be transformed
in like manner. As particular examples, reversing the series,
we have

/

dx . cos(2r— \)x

-(sin#)2r-

_(-D

i-i.

n-\

cos#
AO"-

f

2P(w-l)

dx cos(2r- l)x

>3in*) cos*

1 A20«-1

22

-'o»-n

,2,-1 J.

Alw_1 , A2lw_1

•...+

A8r-21n-l'|

(13.)

, (14.)

'2P(n— 1)1* 2 22 *" ' 22r-2 /■

where A0 = A 1 = Az= 2, 11= m — 2f, and 2; even. We might
find the same integral when n — m — (2/+1), but the formulae
would not be simple.

When z is odd, the latter half of the terms have contrary
signs to the former, and destroy them ; since y~z = if , &c.
But we may continue the series to infinity. Then

,z+l _ o ..-2-2

IC« "* *» 2 V"2-2 - 2j/-,;-4 + &C

Jm.n *s w "

-*-4
m, n

All the terms vanish after z becomes less than (— m) ; but
there will be a remainder +u~p= + up , p being ii.!inite

— m,n — m,iv * »

and even. Now

The Rev. Brice Bronwin on some Definite Integrals. 497

/dx . mcospx _ sinpx (sin.r)OT 1 /». /(sin.r)OT\

xn (sin<r) cos# — ^?cos.r xn pJ V<rncos^/,

which is zero as long as the element of the integral is finite.

it
Let us examine the points where it is infinite. Make x =—

+ u, u infinitesimal. Then

cospx _ cospu _ p cos pu^
cos.r ~ u ~ pu

/pdu cosp u _ Pd v cos v _
p u J V

taken from v= — oo to w= oo , the rest of the element remaining
constant. It will be the same at every other such point. The

remainder «£ . therefore = 0. Hence

wH-i — l^ll)jL_{A(W2-2-2r-1--A1(m--^-4)w--1 + ...}(E-

lP(w-l)

As particular examples,

/dx n cos2rx „ f*dx . cos2r#

cos ^

/

^* • 9,.4.2COs2r,3:, _ (~~1)*,r

-r-(sin*)r+ cosjr -22r+1P(w-l)'

(15.)

jo a fraction greater than 0 and less than 2. We may employ

the method of summation here.

2 pdx , . v sin z x 0.
Let \z _ = / — (sin *)» . Since

- . sin(z+l).r , sin(z— l):r _ « 2+l , .*-l

2s,n2'r = -io7F- + cos* ; 2V« = V« *AM'
We find as before, z being odd, and

_x-^-l_x^+1- A^+1-/ -/~2+ -V~Z.

Am,n —" Am,n ' *m,n ~ um,n um,n * wm,n'

Putting for vzm „, &c. their values from (c), and continuing
the series till it terminates, adding and subtracting the addi-
tional terms, there results

C1=i!i^{A(s + m)»-1-A1(*+m-2)»-1 + ...}

~^P(n-l){A'm-^-2)''"'-A'('"~g~4)"'' + -}
Here n = m — (2 * — 1 ). As a particular example, n > 1, we
Phil. Mag. S. 3. No. \62.Suppl.Vo\,24>. 2K

(F.)

498 Mr. Denham Smith on Ferric Acid.

have

/ — r(sin^rr+I

*y xn cos.r

?2P(»--])t 2 + 22 ",+ 22r J.

When * is even, xj^1 = - 2 w~*~2 + 2 t^-4 _ &c. con-
tinued till they become zero, for all the terms preceding de-
stroy one another, and the remainder of the series supposed
continued to infinity is nothing; for we may prove as before

pdx sin p a; . , . . . . „ .

thaty — (sin x)m — £— is nothing when p is infinite and

odd. Hence by substitution from (c),
^+i= (-1)1* {A(?,i-z-2)n-1-A]{m-z-4)n-1 + ...}

"m,n 2m_1P(w— 1)

\n— 1

•(G.)

+iip(^IjA"(— ):

The last term in (G.), or the correction, is to be left out when
the number of terms in the preceding series is even. As an
example,

r~ ■ v2r + isin (2r— l)o?_ ( — ])»• y

J ^{SmX) cosa? ~ 22'■P(^^-l), ' ( '

2r+l>rc — 1.

We cannot employ any of the formulas of this paper if n — 1

and 0O = tan-1 \~k) enter5 because this quantity is indeter-
minate. In some cases 0O = — leads to true results, but

perhaps it cannot be proved that it must always take this value.
Gunthwaite Half, March 10, 1844.

LXX. Note on a paper on Ferric Acid, read May 16, 1843.

By J. Denham Smith, Esq.*
HPHE paper above referred to, which I had the honour of
•*• laying before the Society last sessionf, was unfortunately
printed before I had proved that two material errors were
contained in it. These errors arose partly from the almost
invariable presence of manganese in the oxide of iron, preci-
pitated from the sulphate, which I employed, — an impurity I
neither suspected nor guarded against, and which usually oc-

* Communicated by the Chemical Society ; having been read December
4, 1843.

f See Memoirs, vol. i. p. 240. [or Phil. Mag. S. 3. vol. xxiii.]

Mr. Denham Smith on Ferric Acid. 499

curs in such minute quantities as to render its detection im-
practicable by the ordinary tests ; and partly from the solubi-
lity of sesquioxide of iron in potash under certain conditions,
— a fact noticed by M. Chodnew*. The first error occurs in
pp. 242—3, [Phil. Mag. S. 3. vol. xxiii. p. 220.] where it is
stated that chlorine gas passed into " the deep amethystine
solution of ferrate of potash, keeping the vessel cool during
the passage of the gas, gives a solution of a lighter colour
than the amethystine liquid." This solution proved to be a
very dilute solution of permanganate of potash. I do not
however find the intensity of colour altered by the gas, and
from the permanent nature of this solution I hope eventually
to succeed in isolating the potash salt.

The second is the more serious error (p. 247), where I an-
nounced the existence of an oxide of iron forming a green salt
with potash ; such a salt I now believe does not exist. I pre-
pared a quantity of this green solution by boiling ferrate of
potash and rapidly filtering the clear green solution ; this
gradually decomposed, and the brown deposit was dissolved
in hydrochloric acid, affording a yellow solution, to which a
solution of hydrochlorate of ammonia was added, and then
caustic ammonia; a small quantity of a reddish-brown floccu-
lent precipitate, resembling sesquioxide of iron, fell ; this col-
lected, washed and redissolved in hydrochloric acid, gave a
yellow solution styptic to the taste, which, diluted and ren-
dered as neutral as possible, immediately struck the respective
colours blue and blood-red, with ferrocyanate and sulpho-
cyanate of potash, evidencing the presence of iron ; the am-
moniacal solution was evaporated to expel excess of ammonia,
and tested with ferrocyanate of potash, when the voluminous
flesh-coloured precipitate, characteristic of manganese, was
produced : potash added to another portion of this ammo-
niacal solution gave, on the application of heat, a small quan-
tity of the dark brown oxide of manganese.

Having, in the paper referred to, satisfied myself that iron
did form a salt with potash, and also that the green salt con-
tained this metal, I was too hastily induced to imagine that
the colours, of the two solutions alluded to, arose from iron,
not anticipating the existence of manganese in the precipitated
sesquioxide of iron. Whether an oxide of iron, intermediate
to the sesqui and teroxide, and possessing the qualities of an
acid, really exists, I am at present unable to state, but hope
to be able to decide this point, as well as to communicate some
new facts respecting ferric acid and its combinations in a fu-
ture paper.

* Journ.fur Prakt. Chemie, Band xxviii.
2 K2

[ 500 ]

LXXI. Observations on Catechuic Acid. By John Thomas

Cooper, Esq.*
A SHORT time since I was requested to visit a tannery
r* where the principal tanning ingredient employed was
catechu, and among other matters my attention was directed
to a whitish substance which made its appearance on the ex-
ternal surface of the leather when the tanning process was
completed, and the uniform appearance of this substance over
the whole surface is considered by the proprietors as the test
of the perfection of their process of tanning, which is usually
accomplished in about fourteen days. The tanning liquor is
prepared by making an imperfect solution of the catechu in
warm water, or in the liquor that has been previously par-
tially exhausted of its tannin by a former operation ; the de-
pilated hides in their usual state are sewn up so as to form
water-tight bags, into which the tanning liquid, prepared as
above, is placed, so as to completely fill them ; they are then
placed on floors and turned once or twice a day into every
possible position to expose the hide as equally as possible to
the action and pressure of the tanning liquid, and as the pro-
cess of tanning advances the appearance of this white matter
becomes more and more evident, until at length it covers the
entire surface of the leather, and sometimes acquires consi-
derable thickness and solidity. In this state, however, it is
contaminated with many impurities, and after repeated trials
to obtain it in a state fit for examination, I found the follow-
ing simple method to answer the purpose I had in view very
well. The matter, as obtained by scraping from the surface of
the leather, was thrown on a filter of linen cloth and washed
with cold water until the water passed through very nearly
colourless ; by this means a quantity of tannin, mucilage, ex-
tractive matter, and a peculiar substance, which I have not
yet examined, were removed; the matter remaining on the
filter was then treated with hot water, either bv washing it
on the filter, or which is better, by removal into" a basin and
heating it with three times its bulk of water to near the boil-
ing point, when a brown-coloured solution was obtained, and
by filtering this while hot in a warm place, the substance which
has the characters of catechuic acid, catechine, or tanningenic
acid, is deposited as it cools, but the deposition of the whole I
find does not take place until many hours after it has become
cold, therefore, after a lapse of about twenty-four hours, it may
be thrown on a filter and washed with cold water, in which

* Communicated by the Chemical Society; having been read December
18, 1843.

Mr. J. T. Cooper on Catechuic Acid. 501

it is nearly insoluble, until the water passes through colour-
less, or very nearly so, and then dried slowly by exposure to
a gentle heat; in this manner the specimen herewith presented
to the Society has been prepared, and which, if examined, will
be found to possess the properties described as appertaining
to catechine, catechuic, or tanningenic acids, namely, a white
substance with a light tint of reddish-brown, a glistening or
micaceous aspect when diffused in water, meagre to the feel,
something like alumina, insolubility in cold water, and ready
solubility, to a great extent, in hot water; forming a brown
solution of greater or less intensity in proportion to the quan-
tity dissolved ; readily soluble in alcohol and aether, and in
the weakest alkaline solutions, without the assistance of heat,
forming brown compounds ; and with the assistance of heat
becoming dark brown, or almost black, owing, it is said, to
the absorption of oxygen from the atmosphere, and its con-
version into what is called japonic acid, fusible per se into a
resinous looking substance by the cautious application of heat,
and if heated much beyond its fusing point becoming charred,
leaving a very bulky charcoal.

If it be considered desirable to undertake the organic ana-
lysis of this substance, in all probability the specimen presented
may require further purification, and by adopting the process
recommended by Svanberg, namely, forming it into a cate-
chuate of lead, and decomposing this by sulphuretted hydro-
gen while warm, may in the hands of others be effectual for
the purpose, but I confess it has not succeeded well with me.

Catechu.
12-3 Water.
62-8 Tannin.

8 '2 Extractive or colouring matter.

2* Resinous matter.

8*5 Mucilaginous or gummy matter.

4.'4 Insoluble matter.

Cutch.

12-8 Water.

Mm a rr. • f41-5 tannin.

47-7 Tannin | 6.g aUered tannin>

9*2 Extractive or colouring matter.
13*6 Mucilaginous or gummy matter.

6-8 Resinous matter.

9*4 Insoluble matter.
99^5

[ 502 ]

LXXII. On a Class of Double Sulphates, containing Soda

and a Magnesian Oxide. By A. R. Arrott, Esq.*
Vl/THEN a mixed solution of sulphate of soda and any of
the magnesian sulphates is allowed to crystallize by
spontaneous evaporation, these salts always separate from their
solution apart and in their ordinary form, no double salt being
produced.

I find however that if the solution be kept at a temperature
exceeding 100° F., the temperature at which anhydrous sul-
phate of soda begins to be deposited, a double salt is formed,
and this is true of all the magnesian sulphates. The double
salts may generally be procured in well-defined crystals, except
that of copper, which is usually deposited as a crystalline crust.

One member of this class of double sulphates, namely the
sulphate of magnesia and soda, was obtained by Dr. Murray
in the manufacture of sulphate of magnesia from sea water,
being produced accidentally during the evaporation of the
liquor ; but he seems not to have been aware of the circum-
stances of its formation.

Several soda salts of the same class were also obtained by
Mr. Graham by a process which he has described, namely,
by mixing strong solutions of bisulphate of soda and the mag-
nesian sulphate in atomic proportions; the double salt sepa-
rated by crystallization in the course of a few days, at the or-
dinary temperature. The reason why no double salt of soda
is formed at low temperatures seems to be the affinity of sul-
phate of soda for water, and the consequent formation of a
hydrated sulphate of that base, which cannot enter into such
combinations.

This interference is, however, prevented by the use of a
high temperature, at which, as is well known, sulphate of soda
is deposited from its solution in the anhydrous condition, and
probably therefore exists dissolved in that state.

The method which succeeds best is to dissolve the salts to-
gether in equivalent quantities, and to evaporate at a tempe-
rature of 130°. In this way I have formed the double salts
of soda with magnesia, zinc, iron, copper and manganese.

The quantity of water contained in 100 parts of these salts
was — Experiment. Theory.

Sulphate of magnesia and soda
zinc
iron
copper
manganese

* Communicated by the Chemical Society; having been read January
1, 1844.

21-68

21-38

4 HO

19-76

19-15

4 HO

19-86

19-69

4 HO

11-00

10-63

2 HO

11-09

10-89

2 HO

Mr. Warington on the Molecular Structure of Silver; SOS

which gives 4 atoms in the magnesia, zinc and iron salts, and
2 in those of manganese and copper, the per-centage of water
observed being in all cases rather above the atomic quantity,
from water mechanically included; double salts being, as is
well known, remarkable for the quantity of hygrometric water
they retain.

The salt of magnesia is generally said, on the authority of
Dr. Murray, to contain 6 atoms of water, but I have never
found it to contain more than 4.

These salts are persistent in air, and may be dried at 212°
without losing their transparency; the salts of manganese and
magnesia decrepitate strongly when heated.

After the loss of their water, these salts are all fusible at a
low red heat, and undergo that change without decomposition.
When the double salt is dissolved in water and the solu-
tion allowed to evaporate spontaneously, its component salts
always crystallize apart, the double salt being entirely de-
composed ; this often happens also with bisulphate of soda.
In consequence of this effect of water the solubility at a low
temperature could not be observed.

When a solution of the copper salt is boiled, a subsalt is
precipitated, resembling the subsalt of copper and potash
formed under similar circumstances. It is of a pale green
colour, loses nothing by drying at 212°, but loses weight and
becomes much deeper in colour when ignited; it therefore
contains water besides an excess of oxide of copper.

LXXIII. On a curious Change in the Molecular Structure of

Silver. By Robert Warington, Esq.*
rT',HE subject of the present brief communication was put into

'• my hands by my friend Mr. Porrett after our last Meet-
ing, as bearing on the subject of the memoir which I bad the
honour of reading before the Society in January 1842f ; a sub-
ject I am still prosecuting, as my time will permit, and the re-
sults of which I hope to lay before the Society at an early date.
It appears, from information furnished me by Mr. Porrett,
to have been part of a silver funeral vase, and was discovered
by some labourers, about four months since, at the depth of
seven feet below the surface of the ground, while digging for
brick-earth between Bow and Stratford. Its height was about
ten inches, and its greatest diameter about eight inches ; it
weighed 40 ounces, and had a smaller vase about the size of
a human heart in its interior. When brought to Mr. Ed-

* Communicated by the Chemical Society; having been read December
18, 1843.

f See Memoirs, vol. i. p. 77. [or Phil. Mag. S. 3. vol. xx. p. 537.]

504 Mr. Warington on the Molecular Structure of Silver.

wards, a watchmaker resident in Shoreditch, by whom it was
purchased, it was without a cover, and the contents had been
thrown away, with the exception of some black ashes, which
were not preserved. Its thickness was about from 0*015 to
0'017 of an inch, its surface presented a dull tarnished aspect,
and was stained in patches with red oxide of iron. It was
extremely rotten and brittle, breaking by the application of
the slightest force ; the surfaces of fracture were uneven and
of a bright white metallic lustre. When examined under the
microscope by a power magnifying 100 diameters it presented
a highly crystalline structure, the facets of the crystals being
exceedingly bright and approaching the cubic form, but none
of them could be observed perfectly developed; they were
more analogous to the characters of grain tin in its broken
state as met with in commerce. It appeared also as though
there had been a recry stall ization of the metal, as the particles
looked as if they had been drawn from the central part to
the sides of the thin plate, leaving cavities or interstices of
considerable extent and depth ; the exterior surface was also
coated with a film of about 0*0005 of an inch thick, having
a grayish-olive colour, and totally different in its structure
from the other parts, being striated across its breadth. The
specific gravity of the metal in this state was found to be
9*937, great care having been taken to remove the air from
the internal cavities by means of the air-pump.

The metal was next heated to redness in a crucible, and
the heat sustained for about ten minutes, after which its cha-
racters were found to be totally altered ; it had lost its extreme
brittleness, requiring to be bent several times before a fracture
could be effected, and then, by the aid of the microscope,
exhibited a close, small grained tough aspect of a dull white
colour, and without the previous cavernous appearances ; the
superficial film seemed also in places to have partially sepa-
rated from the substance of the thin plate of metal during the
bending. The specific gravity was again taken, adopting the
previous precautions, and was found to be 9*95, making an
increase of 0*013 on the gravity taken before the application
of a red heat.

It was next submitted to analysis; 8*5 grains were digested
in dilute nitric acid, and the soluble parts (A) decanted, and
the residue well washed. This residue was in small thin
grayish-white flakes, and by exposure to the light became ra-
pidly of a purple tint, indicating the presence of chloride of
silver ; fearing that this might have arisen from some acci-
dental impurity in the materials employed, both the nitric
acid and distilled water were carefully tested and proved to

Mr. Warington on Preserving Salts for the Microscope. 505

be perfectly pure; it was therefore digested in weak solution
of ammonia, which dissolved the whole, with the exception of
a small quantity of brown powder, which was found to consist
of 0*06 gr. of peroxide of iron and a trace of gold. The am-
moniacal solution was precipitated by nitric acid, and gave
0*52 gr. of chloride of silver. The solution (A) was next
precipitated by solution of chloride of sodium, and gave 10'25
grains of chloride of silver, equivalent to 7*66 grains of silver ;
solution of caustic potash, and boiling threw down the oxide
of copper, and yielded 0*30 gr. oxide of copper = 0'24 gr. of
copper. Thus we have —

Silver 7*66 grains.

Chloride of silver. . . 0'52

Copper 0*24

Oxide of iron. . . . 0*06

Gold a trace

8*48
Loss . 0*02

8-50

It becomes a curious question as to the origin of this chlo-
ride of silver, which was evidently the superficial grayish film
observed under the microscope, and which partially separated
in the act of bending the metal after heating. That it must
have been produced by the continued action of chlorides, per-
haps aided by sulphates present in the brick clay from which
the vase was excavated, there can be little doubt, and the per-
oxide of iron also existing in the clay may have assisted this
action.

The passage of the metal to the brittle state in this and in
all other cases will, I think, be found attributable to some
electrical action arising from sudden cooling, vibration or
concussion, chemical action, &c. to which the metallic body
or alloy may have been exposed.

LXXIV. Note on a Means of Preserving the Crystals of Salts
as permanent objects for Microscopic Investigation. By
Robert Warington, Esq*
tTAVING occasion lately to require the crystals of various
•*--*■ salts in a state fitted for examination by polarized light
under the microscope, and as the preparation of these crystals
was frequently attended with much trouble and loss of time,
it became a point of importance to render the object, when
once perfected, permanent, so that the investigation of certain
individual crystals could be repeated, and additional obser-

* Communicated by the Chemical Society; having been read January
15, 1844.

506 Mr. Warington on Preserving Salts for the Microscope.

vations made at any period. This was rendered the more de-
sirable from the difficulty of obtaining perfect and isolated
subjects, and the rapidity with which many of these undergo
alteration by exposure to the air. With some few salts this
operation was comparatively easy, as the Canada balsam
offered an excellent medium for the purpose, but in the greater
number of cases I have examined it proved totally indifferent ;
and this arises from two causes, the first from the action of
the turpentine contained in the balsam rendering the sur-
faces of the crystals opalescent ; the second, from the heat,
which it was necessary to apply to make the balsam suffi-
ciently fluid to displace the atmospheric air, fusing the salt in
its water of crystallization, or rendering it opake from the
loss of water. Olive oil on trial appeared a good medium for
all cases, but was objectionable from its fluidity, and from its
depositing its stearine in cold weather. Castor oil was then
tried, and this I have adopted with great satisfaction.

The method to be adopted in mounting these specimens is
as follows : — A warm saturated solution of the salt required is
to be prepared, and a drop of it placed upon the glass slider,
on which it is intended to be permanently mounted, and al-
lowed to crystallize; when a good group of crystals is ob-
tained the uncrystallized portion is to be cautiously removed;
this is best effected by drawing it gradually away in a small
stream along the edge of the slider, having previously broken
through that part of the crystalline ring adjacent to the edge;
the salt is to be allowed to drain itself quite dry by placing the
slider on its end in a vertical position. It should next be exa-
mined under the microscope, to ascertain the fitness of the
crystals for the purposes required, because many salts separate
from their solutions in crystals too thin to exhibit any pris-
matic colours when viewed by polarized light, appearing only
of a pearly or silvery aspect, while others form in the oppo-
site extreme, and are totally unfit, from their thickness, for
investigation. Presuming, however, that the crystals are such
as the investigator requires, the next step is to drop on a
small quantity of castor oil; that which has been filtered cold
must be employed, as otherwise it is liable to the same ob-
jection as olive oil, and care must be taken that it covers the
whole of the salt, and has displaced all the particles of atmo-
spheric air that may have been adhering to the crystals. This
having been done, a small piece of very thin glass is to be
carefully placed on the surface of the oil, and any excess which
may by this means have been pressed out, cautiously removed
by bibulous paper from the edges. Two or three coats
of a strong varnish of shell -lac, as ordinary sealing-wax in

Mr. Warington on the Green Teas of Commerce. 507

spirits of wine, or japanners' gold size, are then to be placed
round the margin, so as completely to inclose the oil, and the
crystals are permanently preserved for observation. It may
be perhaps as well to observe, that the one layer of varnish
must be allowed to dry for about twenty-four hours before the
next is applied, and that during this time the slider must be
maintained in a flat position.

LXXV. Observations on the Green Teas of Commerce.
By Robert Warington, Esq.*

IN examining lately some samples of tea which had been
seized, from their being supposed to be spurious, my
attention was arrested by the varied tints which the sample
of green tea exhibited, extending from a dull olive to a bright
greenish blue colour. On submitting this to the scrutinizing
test of examination by the microscope with a magnifying
power of one hundred times linear, the object being illumi-
nated by reflected light, the cause of this variation of colour
was immediately rendered apparent, for it was found that the
curled leaves were entirely covered with a white powder ha-
ving in places a slightly glistening aspect, and these were
interspersed with small granules of a bright blue colour, and
others of an orange tint : in the folded and consequently more
protected parts of the curled leaves these were more distinctly
visible. By shaking the whole of the sample mechanically for
a short time a quantity of powder was detached, and from this
a number of the blue particles were picked out under a mag-
nifying glass, by means of the moistened point of a fine camel's
hair pencil. On being crushed in water between two plates
of glass they presented, when viewed by transmitted light,
a bright blue streak. This change in the method of illumi-
nating the object was necessary for the purpose of seeing the
action of the following tests: — A minute drop of a solution of
caustic potash was introduced by capillary attraction between
the glass plates, and the blue tint was immediately converted
to a dark bright brown, and the original blue colour again
restored by the introduction of a little dilute sulphuric acid.
It was therefore evident that these particles consisted of the fer-
rocyanide of iron or Prussian blue. The orange granules on
examination proved to be some vegetable colouring substance.

To ascertain if possible the nature of the white powder ob-
served on this sample, I separated some of the dust, and
heated it to redness with free exposure to the air; the whole
of the vegetable matter and Prussian blue was thus destroyed,

* Communicated by the Chemical Society ; having been read February
5, 1844.

508 Mr. Warington on the Green Teas of Commerce.

and a white powder, with a slight shade of brown, was ob-
tained. This dissolved by boiling in dilute hydrochloric acid,
and when tested with solution of chloride of barium gave in-
dications of sulphuric acid ; it was then evaporated to dry-
ness and again acted upon by very dilute hydrochloric acid;
a trace of silica remained undissolved. Solution of ammonia
being added threw down a little alumina and oxide of iron, and
the ammoniacal solution treated with oxalic acid gave a pre-
cipitate of oxalate of lime. A second portion of the powder
after calcination was boiled for some time in distilled water,
and yielded a solution containing sulphate of lime ; this latter
substance, therefore, and some other body containing silica,
alumina, and perhaps lime, formed the white powder observed.
This substance I believe to be kaolin, or powdered agalmato-
lite, the figure stone of the Chinese. I venture this conjecture
not only from the ingredients found, but also from the gloss
which the rubbed parts of the curled leaves always assume, and
which these materials would be well fitted to produce.

Four or five other samples of green teas were then sub-
mitted to the same method of examination, and only one of
them proved to be free from these blue granules; this sample
was a high-priced tea, and had been purchased about two
years ; it appeared covered with a very pale blue powder, in-
stead of the white with the blue particles interspersed, as ex-
hibited by the others.

Being still in doubt as to whether this powder and colouring
was an adulteration practised in this country or not, I applied
to a most extensive wholesale dealer of the highest respecta-
bility, and from him obtained a series of samples, each being
an average from a number of original chests, and from these
I gathered the following results by examination, as before, with
the microscope. No. 1. Imperial. The leaf, where seen be-
neath the superficial coating, was of a bright olive brown
colour, with small filaments on its surface; it was covered
with a fine white powder and with here and there a minute
bright blue particle, at times having the appearance of a stain.
No. 2. Gunpowder. Similar to No. 1, but the filaments not
visible: this may have arisen from the tight and close man-
ner in which the leaf was curled. No. 3. Hyson. The same
as No. 1, the blue particles being perhaps more frequent.
No. 4. Young Hyson. The same. No. 5. Twankey. The
leaf of this had more of a yellow hue, and was profusely
covered with white powder, having the blue particles also
more thickly strewn over the surface. It was evident from
the examination of these teas that they arrive in this country
in an adulterated or factitious state.

Mr. Warington on the Green Teas of Commerce. 509

On detailing what I had thus found to the friend who had
favoured me with the preceding samples, he inquired if I had
examined any unglazed teas. This appellation immediately ar-
rested my attention, and I requested to inspect some of them,
and found that they possessed externally a totally different
aspect, indeed, as far as their colour was concerned, not to
be like green teas. They were of a yellow-brown tint without
a shade of green or blue, but rather tending on the rubbed
parts to a blackish hue. I afterwards received two samples
of unglazed teas, specified as of very fine quality, accompa-
nied by two others of the ordinary or, as they are called, in
contradistinction, glazed varieties, also of a very superior qua-
lity. These were therefore immediately submitted to exami-
nation. No. 6. Unglazed Gunpowder. It presented the same
colour under the microscope as when viewed by the unas-
sisted eye, was filamentous and covered with a white powder
inclining to a brown tint, but no shade of blue was visbile.
No. 7. Unglazed Hyson. The same as No. 6. No. 8. Gun-
powder glazed. Filamentous, covered with a powder of a very
pale blue, and the blue granules being but rarely seen. No. 9.
Hyson. The same as No. 8. No. 10. Pidding's Howqua,
purchased at Littlejohn's at 85. 6d. per catty package. This
was evidently of the glazed variety ; it was filamentous and
covered with a pale blue powder interspersed with bright
blue granules. No. 11, entitled Canton Gunpowder. This
was a splendid sample of the glazed variety, as far as colour
was concerned ; it was more thickly powdered and blued than
any that I have examined, and the dust rose from it in quan-
tity when poured from one paper to another. A great many
other samples of ordinary green teas were examined, with
much the same results ; the cheaper teas, or those in general
use, and which form the bulk of the imports, being similar to
Nos. 5 and 11, and being represented by Twankeys and low-
priced Hysons or Gunpowders.

After several unsuccessful experiments, I found that with a
little care the whole of this powder or facing, if I may be
allowed the term, it being entirely superficial, could be easily
removed from the tea, by simply agitating the sample briskly
for a few seconds in a phial with distilled water, and then
throwing the whole on a lawn or muslin filter, in order to
strain the liquid, with the suspended matter, from the leaves
as rapidly as possible. After this operation the tea presented
a totally altered aspect, as may be supposed; in fact, changing
its colour from a bluish green to a bright and lively yellow
or brownish yellow tint, and I found that with care it could
be redried at a temperature below 212° without even uncurl-

510 Mr. Warington on the Green Teas of Commerce.

ing the leaf, and without apparent loss of any of its charac-
teristic qualities. When the drying was complete the sample
appeared nearly as dark as the ordinary black teas, and when
examined by the microscope presented a smooth surface, per-
fectly free from the previously observed facing, and having
all the characters of black tea, with the exception of the corru-
gated aspect which is common to the greater part of the teas of
the latter variety, and which evidently arises from their having
been exposed in the operation of drying to a much higher
temperature. The greenish-coloured turbid liquid which
passed through the meshes of the muslin filter was allowed
to deposit the matter suspended in it, which was then washed
and collected. These sediments, obtained from various sam-
ples, were submitted to the following course of chemical ex-
amination. They were, in the first instance, tested with a
solution of chlorine gas in water, to ascertain if the colouring
material was indigo or other vegetable colour; this substance,
as we shall presently see, having been supposed by some
persons to be the one employed by the Chinese for the purpose
of imparting the blue tint to some of their green teas. In
no case, however, that I have yet examined have I found
this to be the case ; but the colouring agent has invariably
proved to be the ferrocyanide of iron or Prussian blue. The
presence of this compound was next evidenced by adding a
small drop of caustic potash to a little of the sediment under
examination, when the green hue was instantly converted to
a bright reddish brown, the original blue appearance being
again restored by the subsequent addition of a little diluted
sulphuric acid. The other ingredients of the facing were
sought for in the manner stated in the previous part of this
paper, and also by heating a part of the sediment, after cal-
cination and free exposure to the air, with carbonate of soda,
to fusion, which, in the case of sulphate of lime being present,
formed sulphate of soda and carbonate of lime, and these were
each subsequently tested for.

By these means Nos. 5, 8, 10 and 1 1 were found to be faced
with Prussian blue and sulphate of lime. Nos. 6 and 7 gave
no indication of Prussian blue, but of sulphate of lime only.
The sulphate of lime from some samples appeared to be cry-
stallized gypsum reduced to a fine powder, the coarser parti-
cles still exhibiting a crystalline structure.

Through the kindness of Mr. Greene, of the East India
House, I was enabled to obtain samples of the Assam teas in
a genuine condition ; No. 12. Imperial, No. 13. Gunpowder,
and No. 14. Hyson. They had none of the blue granules,
were very filamentous, and presented the same appearance as

Mr. Warington on the Green Teas of Commerce. 511

the unglazed varieties, but brighter in colour ; the facing was
apparently sulphate of lime. No. 15. Assam Hyson, of the last
importation ; it was of the unglazed variety, with the super-
ficial white powder having a slight brown tint, and consisting
of a minute quantity of sulphate of lime with a little alumina.

It appears, therefore, from these examinations that all the
green teas that are imported into this country are faced or
covered superficially with a powder consisting of either Prus-
sian blue and sulphate of lime or gypsum, as in the majority
of samples examined, with occasionally a yellow or orange-co-
loured vegetable substance; or of sulphate of lime previously
stained with Prussian blue, as in Nos. 8 and 9, and one of
those first investigated ; or of Prussian blue, the orange-co-
loured substance with sulphate of lime and a material sup-
posed to be kaolin, as in the original sample; or of sulphate
of lime alone, as in the unglazed varieties. It is a curious
question what the object for the employment of this facing can
be ; whether, as when sulphate of lime alone is used, it is simply
added as an absorbent of thelastportions of moisture which can-
not be entirely dissipated in the process of drying, or whether
it is only, as 1 believe, to give that peculiar bloom and colour
so characteristic of the varieties of green tea, and which is so
generally looked for by the, consumer, that the want of the
green colour, as in the unglazed variety, I am informed affects
the selling price most materially. This surely can only arise
from the want of the above facts being generally known, as it
would be ridiculous to imagine that a painted and adulterated
article, for such it must really be considered, should maintain
a preference over a more genuine one. In looking over the
various authors who have written on the subject of tea, I have
observed the following curious statements bearing on the
above subject, and fully confirming many of my results, and
with which I shall close the present communication.

In Dr. Horsfield's valuable translation* on the subject of
the manufacture of tea in Java, we find, at page 36, the fol-
lowing dialogue : —

" Visitor. Is it indeed the case that tea is so much adulte-
rated in China ?

f* Superintendent. Unquestionably ! but not in the interior
provinces, for there exist rigid laws against the adulteration
of tea ; and all teas, as they come out of the plantations, are
examined on the part of government, to determine whether
they are genuine ; but in Canton, which is the emporium of
teas, and especially at Honan, many sorts, indeed most teas,

* Essay on the Cultivation and Manufacture of Tea in Java, translated
from the Dutch by Thomas Horsfield, M.D., F.R.S.

512 Mr. Warington on the Green Teas of Commerce.

are greatly adulterated, and that with ingredients injurious to
health, especially if too much of these ingredients be added.
This is especially the case with the green tea, in order to im-
prove the colour ; and in this manner to add to the value of
tea in the eyes of the common consumers.

" Visitor. Are these ingredients known ?

" Superintendent. Most of them are certainly known ; they
have been communicated to government (we presume the
Dutch government), while at the same time the privilege has
been requested that they might not be employed here ; and al-
though this occasions loss, the request has* been granted, and
it has been ordered by government that not the least admix-
ture should take place, either to improve the colour or taste
of the tea, even in such cases where this might be desirable."

Dr. Royle states*, " The Chinese in the neighbourhood of
Canton are able to prepare a tea which can be coloured and
made up to imitate various qualities of green tea; and large
quantities are thus yearly made up." And Dr. Dickson f, —
" The Chinese annually dry many millions of pounds of the
leaves of different plants to mingle with the genuine, as those
of the ash, plum, &c, so that all spurious leaves found in
parcels of bad tea must not be supposed to be introduced into
them by dealers in this country. While the tea trade was
entirely in the hands of the East India Company few of these
adulterated teas were shipped for this country, as experienced
and competent inspectors were kept at Canton, to prevent the
exportation of such in the Company's ships; but since the
trade has been opened all kinds find a ready outlet, and as the
demand often exceeds the supply, a manufactured article is
furnished to the rival crews."

During these investigations I have received samples of teas,
both green and black, imported into this country from China,
which are known, by the most experienced brokers, not to
contain a single leaf of tea, and which were sold at public sale
in bond at from lfrf. to 2o". per pound.

Again, — " The green tea for exportation undergoes some
process which changes its colour, giving it a bluish green
hue."

Mr. Davis J gives the following important information on
this subject: — "The tea farmers§, who are small proprietors
or cultivators, give the tea a rough preparation, and then take
it to the contractors, whose business it is to adapt its further
preparation to the existing nature of the demand."

* Article Thea in the ' Penny Cyclopaedia.'

f Article Thea, Medical and Dietetical, * Penny Cyclopaedia.'

J Davis's ' Chinese.' § Vol. ii. p. 458.

Mr. Warington on the Green Teas of Commerce. 5 1 3

" Young hyson*, until spoiled by the large demand of the
Americans, was a delicate, genuine leaf." "As it could not be
fairly produced in any large quantities, the call for it on the
part of the Americans was answered by cutting up and sifting
other green teas through sieves of a certain size ; and as the
Company's inspectors detected the imposture, it formed no
portion of their London importations. But the abuse became
still worse of late, for the coarsest black tea leaves have been
cut up, and then coloured with a preparation resembling the
hue of green teas." At page 4>66 Mr. Davis continues, after
speaking of the frauds with spurious and adulterated teas
which the Chinese had endeavoured to practise, " But this
was nothing in comparison with the effrontery which the
Chinese displayed in carrying on an extensive manufactory of
green teas from damaged black leaves, at a village or suburb
called Honan."

"The remission of the tea duties in the United States occa-
sioned, in the years 1832 and 1833, a demand for green teas
at Canton which could not be supplied by the arrivals from
the provinces. The Americans, however, were obliged to sail
with cargoes of green teas within the favourable season; they
were determined to have these teas, and the Chinese were
determined they should be supplied. Certain rumours being
afloat concerning the manufacture of green tea from old black
leaves, the writer of this became curious to ascertain the truth,
and with some difficulty persuaded a Hong merchant to con-
duct him, accompanied by one of the inspectors, to the place
where the operation was carried on." " Entering one of these
laboratories of fictitious hyson, the party were witnesses to a
strange scene." The damaged black tea leaves, after being
dried, were transferred to a cast iron pan placed over a fur-
nace, and stirred rapidly with the hand, " a small quantity of
turmeric in powder having been previously introduced ; this
gave the leaves a yellowish or orange tinge, but they were
still to be made green. For this purpose some lumps of a
fine blue were produced, together with a substance in pow-
der, which, from the names given to them by the workmen,
as well as their appearance, were known at once to be Prussian
blue and gypsum. These were triturated finely together with a
small pestle, in such proportions as reduced the dark colour
of the blue to a light shade; and a quantity equal to a tea-
spoonful of the powder being added to the yellowish leaves,
these were stirred as before over the fire, until the tea had
taken the fine bloom colour of hyson, with very much the same
scent. To prevent all possibility of error regarding the sub-

* p. 464.

Phil. Mag. S. 3. No. 162. Sttppi. Vol. 24-. 2 L

514- Mr. Warington on the Green Teas of Commerce.

stances employed samples of them were carried away from the
place. The Chinese seemed quite conscious of the real cha-
racter of the occupation in which they were engaged ; for, on
attempting to enter several other places where the same pro-
cess was going on, the doors were speedily closed upon the
party. Indeed, had it not been for the influence of the
Hongist who conducted them, there would have been little
chance of their seeing as much as they did*." " Jt is an in-
teresting and important question to determine whether the
same system of artificial colouring enters at all into the manu-
facture of the more genuine green teas brought to this coun-
try." " One fact is well ascertained and undeniable, that the
Chinese themselves do not consume those kinds of green teas
which are prepared for exportation t." " The young hyson
and Pekoe teas, made from the green tea plant, have a yellower
and as it were a more natural hue than the bluish-green that
distinguishes the elaborated teas imported to us."

Mr. Bruce states % that in the last operation for colouring
the green teas "a mixture of sulphate of lime and indigo,
very finely pulverized and sifted through fine muslin, in the
proportion of three of the former to one of the latter, is added
to a pan of tea containing about seven pounds, about half a
tea spoonful of this mixture is put, and rubbed and rolled
along with the tea in the pan for about an hour. The above
mixture is merely to give it a uniform colour and appearance.
The indigo gives it the colour, and the sulphate of lime fixes
it. The Chinese call the former Youngtin, the latter Acco"

Indigo however, as previously stated, has never yet been
met with on any of the green teas of commerce that have
fallen under my notice.

The following curious observation occurs in Maculloch's
* Commercial Dictionary:' — " Blue is a favourite colour with
the Chinese; and in 1810 — 11 the imports of Prussian blue
into Canton from England amounted to 253,200 pounds. But
for some years past the Chinese have not imported a single
pound weight. The cause of the cessation of the trade deserves
to be mentioned. A common Chinese sailor, who came to
England in an East Indiaman, having frequented a manufac-
tory where the drug was prepared, learned the art of making
it, and on his return to China he established a similar work
there with such success that the whole empire is now supplied
with native Prussian blue."

* Vol. ii. p. 468. f Vol. ii. p. 469.

X Report on the Manufacture of Tea, and on the extent and produce
of the Tea Plantations in Assam, by Mr. C. A. Bruce, Superintendent of
Tea Culture, presented to the Tea Committee, August 16, 1839.

[515]

LXXVI. Account of a new Cyanide of Gold.
By Mr. John Carty*.
'TWERE is one compound of cyanogen and gold known at
x present to chemists ; it is a tercyanide, or contains 3 equi-
valents of cyanogen combined with one of gold. Having ob-
served indications of a protocyanide, and not rinding it men-
tioned in the chemical works usually referred to, I tried to
obtain it pure, and have, I believe, succeeded by the following
method : —

Protochloride of gold was decomposed by cyanide of po-
tassium in solution. An abundance of a yellow matter ap-
peared at first, but an excess of the cyanide gave a clear and
perfect solution. To this solution muriatic acid in excess was
added ; on boiling a bright yellow powder precipitated, which
was washed and dried by a moderate heat. It was insoluble
in water, alcohol and aether; soluble in ammonia and in solu-
tion of cyanide of potassium. It was decomposed by heat,
like a cyanide, and nothing but cyanogen gas was driven off.
It was not decomposed by strong boiling muriatic or nitric
acid, or by a solution of chlorine, but was decomposed, though
not rapidly, by hot nitro-muriatic acid, and very slowly by so-
lution of potash ; boiling sulphuric acid liberated metallic gold.

30'7 grains of the yellow powder were heated to redness in
the air, 27*0 of gold remained, 3*7 of cyanogen were therefore
driven off. Other experiments on smaller quantities agreed
closely with this, and they show the yellow substance to have
been composed as near as may be of 200 of gold and 26 of
cyanogen ; and it is therefore a protocyanide of gold.

When tercyanide of gold was dissolved in boiling muriatic
acid, and the solution concentrated, protocyanide of gold was
gradually deposited as a yellow powder. 2 atoms of cyanogen
were removed, probably by forming ammoniacal compounds
with the elements of the water which is present.

The protocyanide of gold was dissolved in hot ammonia;
on cooling an abundance of gray glistening plates fell, which
were found to be a compound of the protocyanide and am-
monia. The ammonia was easily removed by a gentle heat,
or by hot muriatic acid leaving the protocyanide.

Protocyanide of gold was dissolved in solution of cyanide
of potassium. By evaporating the liquid, long prismatic
white crystals, nearly opake, anhydrous and somewhat de-
liquescent, were obtained. They were decomposed by heat
into gold, cyanogen gas and cyanide of potassium. A solu-
tion of them was not soon affected «by muriatic acid in the cold,

* Communicated by the Chemical Society; having been read February
19, 1844.

2 L 2

516 Royal Astronomical Society.

but on boiling the liquid for a minute or two protocyanide of
gold was precipitated, and no gold remained in solution. By
analysis it appeared to consist of one equivalent of protocyanide
of gold with 2 of cyanide of potassium *.

From these experiments we may conclude, — 1. That there
is a protocyanide of gold remarkable for being the most stable
of all the cyanides, except perhaps cyanide of palladium.
2. That tercyanide of gold is reduced to protocyanide by
boiling muriatic acid. 3. That the protocyanide combines
with ammonia and with cyanide of potassium.

LXXVII. Proceedings of Learned Societies.

ROYAL ASTRONOMICAL SOCIETY.

[Continued from p. 308.]

December 8, f|1HE following communications were read : — I. On

1843. JL the Apparent Magnitudes of the Fixed Stars.

By C. Piazzi Smyth, Esq. Communicated by Captain W. H. Smyth,

R.N.

The author complains of the want of information on the methods
of observing the apparent magnitudes of the stars, and of the little
attention which has been paid to the proposal of a prize for a suc-
cessful photometer (Memoirs, vol. i. p. 507), by the Astronomical
Society.

He proposes to employ telescopic vision, and to measure the
degrees of brightness of every star by means of the obscuration
which is necessary to make it vanish. By this means, the necessity
of direct comparison between stars taken two and two is avoided,
and an absolute zero is established.

For producing the obscuration, he proposes, in the first place, a
long wedge of blue coloured glass (with its prismatic qualities coun-
teracted by a similar transparent wedge), made to slide between the
object and eye-glasses, a little way out of focus. This wedge might
be fixed on the eye end of the telescope, mounted either in a micro-
meter frame, or made to move in the manner of a barometer scale.

Another plan is, to have a coloured disc of glass in the tube, ca-
pable of sliding up and down in it, by which means the object will
be differently obscured, on account of the variation of the diameter
of the pencil of rays at different distances.

The author then dwells on the method of observation, the means
of getting rid of the atmospheric effect, the establishment of a com-
mon unit of comparison, and the obviation of the practical difficulty
of obtaining a uniform rate of obscuration.

* After the reading of this paper before the Chemical Society, a paper
on the same cyanide of gold, by Messrs. Glassford and Napier, was read, in
which the composition of the double cyanide of potassium and gold was
stated to be 1 eq. of protocyanide of gold, 1 of cyanide of potassium and
1 of water, and on carefully repeating my analysis I found their statement
to be correct.

Royal Astronomical Society. 517

II. On an Astronomical Time Watchcase. By the Rev. Professor
Chevallier.

The author has invented a contrivance, by means of which a com-
mon watch can, at pleasure, be made to denote sidereal time, nearly
enough for the purpose of warning an observer when his presence
will be wanted in the observatory.

The principle of the contrivance is to set a moveable face to the
hands of the watch i7istead of setting the moveable hands to a fixed face.
This is effected by means of a circular box containing the watch.
The lid has a circular aperture, through which the hands of the
watch may be seen. Upon the lid is a circular plate, upon which is
engraved a double circle of hours, from 0 to 1 2 and from 1 2 to 24 ;
and a concentric inner circular plate, moveable separately, upon
which the minutes are engraved. A small pointer projects from the
part of the inner circle, which indicates 60m, directing the eye at
once to that point as the temporary upper part of the face.

In order to set this watch-case for use, it is quite unimportant
what time the watch itself indicates. The lid is simply placed so
that the hour-hand of the watch may point to the part of the hour-
circle corresponding to the sidereal hour : the minute-circle being
subsequently turned, till the minute corresponding to the minute of
sidereal time is opposite to the minute-hand of the watch.

The hands of the watch then, as referred to the temporary position
of the moveable circles, indicate sidereal time ; and, if they are set a
little too fast, they will continue to do so to the nearest minute for
almost six hours ; thus giving the observer upon his table a dupli-
cate of his observatory clock, sufficiently exact for the purpose which
he wants.

. It is plain that this contrivance can, with the greatest ease, be ap-
plied to any common watch-case ; or, if a watch-glass were made
capable of being turned round, the hours might be marked upon the
glass, the minutes being engraved upon a moveable rim upon the
watch-case.

III. Mean Places, for Jan. 1, 1842, of 50 Telescopic Stars, within
two degrees North Polar Distance, observed in the years 1842 and
1843, at Markree, in the County of Sligo. By E. J. Cooper, Esq.
and A. Graham, Esq.

IV. On the Orbits of several ancient Comets. By J. R. Hind,
Esq. of the Royal Observatory, Greenwich. Communicated by the
Rev. R. Main.

V. Approximate Elements of the Orbit of the Comet recently
discovered by M. Faye. By Professor Henderson.

VI. Two circular letters from Professor Schumacher on the Comet
discovered by M. Faye. Communicated by F. Baily, Esq.

Abstracts of the preceding four communications are given in the
Society's Monthly Notices, vol. vi. No. 2.

VII. Results of Observations made with a Sextant and Pocket
Chronometer, for determining the Latitude and Longitude of the
Apartments of the Society. By J. Hartnup, Esq. Communicated
by Captain W. H. Smyth, R.N.

518 Royal Astronomical Society.

The resulting longitude is the mean of nine partial results, de-
duced from observations included between June 24, 1842, and May
4, 1843. The mean of these results gives 27s,38 west of Green-
wich, the extreme difference being 0S*82.

From six partial results, obtained between November 12, 1842,
and January 4, 1843, the latitude of the east end of the terrace was
found to be 51° 30' 34"'9 north ; the extreme difference being 3"'4.
Whence the latitude of the apartments of the Society results
51° 30' 38"-3 north.

Particulars of the observations are given in the Monthly Notices,
in which also is an additional communication from Professor Hen-
derson respecting the comet discovered by M. Faye.

January 12, 1844. — The following communications were read : —

I. On the Advantages of employing Large Specula and Elevated
Situations for Astronomical Observations. By C. Piazzi Smyth,
Esq. Communicated by Captain W. H. Smyth, R.N.

The author adverts to methods proposed by Mr. H. F. Talbot for
the multiplication of copies of specula by means of the electrotype,
and for observing astronomical objects with a telescope absolutely
fixed, by means of a revolving plane mirror, which methods he con-
siders might, if carried out, produce great improvements in astro-
nomy. Amongst the advantages of the latter method he enumerates
the following, arising chiefly from the unlimited focal length which
it would be possible to give to the mirror : — first, the obviation of
the necessity of an accurate parabolic shape for the reflector ; se-
condly, the magnifying of the image without distortion or colour ;
thirdly, the small effect which inaccuracies of the screw of the mi-
crometer would produce, eye-pieces of low power being employed ;
fourthly, the elimination of errors dependent on the contraction or
expansion of the tubes of telescopes ; and lastly, the advantage of
having the eye in a fixed position.

The author then enlarges on the advantages which would attend
the use of such a fixed telescope if placed on the slope of a high
mountain, with the object-mirror and the eye-piece fixed on piers,
and separated by a considerable interval, the mirror being beneath.
The Nilgherry hills in India he instances as being favourable for the
purpose, the climate being particularly well suited for astronomical
observations. He then answers the obvious objection of the impos-
sibility of reflecting objects from every part of the heavens to the
speculum, by assuming that it would be most advantageous for as-
tronomical science that every observatory should confine itself to
those classes of objects which its geographical position enables it
most readily to command. He finally dwells upon the cheapness of
the labour of computation in India, arising from the circumstance of
the great number of Brahmin priests who are willing and competent
to undertake the labour for a very trifling remuneration.

II. Observations of the Planet Uranus, made in the year 1843.
By C. Rumker, Esq. Communicated by Dr. Lee.

The observations extend from September 10 to October 31.
They are corrected for refraction, but not for parallax.

Royal Astronomical Society. 519

III. A letter was read from Professor Schumacher to Mr. Baily,
dated January 5, 1844, enclosing the Elements of the New Comet,
computed hy Dr. Goldschmidt, at the request of Professor Gauss,
and which are as follows : —

Epoch of Mean Longitude, 1 843, Dec. 2d* 11 876 Berlin mean time, 58°31'39"
(from the apparent equinox).
Mean daily motion 535"*7079

Perihelion 52 32 55

Angle of eccentricity 31 29 39

Log. semi-axis major 0*5473857

Node 208 21 20

Inclination 10 58 58

And he remarks that, if the observations of the comet that have re-
cently been made can be depended on, the orbit approaches the
nearest to a circle of any that are yet known.

IV. On the Orbit of the Comet of Faye. By Professor Henderson.

Professor Challis had the kindness to communicate to me the fol-
lowing places of the comet observed at Cambridge. They were
determined by comparison with 23 and 32 Orionis, and he believes
that they are pretty accurate.

Mean time from Greenwich Apparent R.A. Apparent N.P.D.

Mean noon. of comet. of comet,

hms hms o / //

1843 Nov. 29 11 12 23 5 21 37"5 84 24 55

Dec. 8 9 59 18 5 17 287 85 47 53

16 11 55 45 5 13 330 86 35 55

Suspecting that the great differences between the elements of the
two parabolic orbits which I formerly communicated, might arise
from errors in the observations employed, I proceeded to investigate
the elements anew from the Cambridge observations. I followed
the method of Olbers, and, after repeated approximations, the best
parabolic orbit which I obtained, differing considerably from both
the former, did not represent the middle observation to within six
minutes of space.

This quantity being much too great to be imputed to error of ob-
servation, I concluded that the orbit was not parabolic, this suppo-
sition seeming to explain the discordances of the elements.

I next investigated the conic section in which the comet moves,
according to the method of Gauss in the Theoria Motus Corporum
Celestium, employing the three observations at Cambridge ; and I
obtained an elliptic orbit, whose period of revolution is about six
years and a half. The elements are

Time of perihelion passage, Oct. 23d6970 Greenwich mean time.

O I II

Longitude of perihelion 52 57 52\ cioaai\

Longitude of ascending node 208 7 28}niean eq. of 18440.

Inclination 10 55 23

Eccentricity sin 31 20 58

Logarithm of semi-axis major 0*545352

Mean daily motion 539"*484

Time of revolution 6*57702 sidereal years.

Motion direct.

520 Royal Astronomical Society,

The following expressions for the comet's co-ordinates enable its
geocentric positions to be more readily computed : —

x = [0-50302] sin (e + 138 '5 32) — 1-10654

y— [0-50843] sin (e + 55 35 24) — 1-38397

z = [9-94451] sin (e + 74 56 1 1) — 0-44213

e denoting the eccentric anomaly.

The errors of the computed places for all the observations which
have reached me are as follows : —

11. A. Declination.

Nov. 22 Paris —303 -19

24

—

1

+ 7

29

Cambridge..

• +

18

+ 10

Kensington..

. +

3

+ 1

Greenwich ..

• +

42

+ 2

2

Edinburgh ..

6

-17

8

Cambridge..

'. +

15

+ 12

15

Edinburgh ..

• +

7

+ 46

16

Cambridge..

• +

23

+ 12

25

Edinburgh ..

. —

40

+ 23

Dec.

The first observation of right ascension at Paris must be affected
with a considerable error.

[An ephemeris of the comet for January and February 1844 is
here given in vol. vi. No. 3 of the Monthly Notices.]

In several respects this comet is very remarkable ; and it may
afford room for speculation regarding its identity with the lost comet
of 1770. The orbit resembles more nearly the elliptical orbits of the
planets than those of the periodic comets yet known. In its aphe-
lion and perihelion it approaches nearly the orbits of Jupiter and
Mars ; and it must occasionally experience great perturbations from
the former. It also passes within comparatively small distances of
the orbits of the minor planets.

I have to-day received Professor Schumacher's circular, dated the
5th instant, communicating Dr. Goldschmidt's elements, which are
nearly the same as mine. They may be considered as confirming
each other.

I obtained an observation of the comet on December 25. Another
on December 20 is not yet reduced, the star of comparison being un-
determined.

Mean time at Edinburgh. R.A. Declination,

hms hms 0 / /;

Dec. 25 11 31 58 5 10 4*6 +3 1 42

Edinburgh, January 10, 1844.

V. A Letter from Professor Henderson announcing an additional
Observation of the Comet of Faye, for which we refer to the Monthly
Notices.

VI. Elements of the Comet of Faye, computed by J. C. Adams,
Esq. of St. John's College, Cambridge. Communicated by Professor
Challis.

The observations used were made with the Northumberland Tele-

Royal Astronomical Society.

521

scope of the Cambridge Observatory ; and the deduced places are as
follows : —

Greenwich mean
solar time.

Apparent R.A.
of comet.

Apparent N.P.D.
of comet.

h m s

Nov. 29 11 12 23

Dec. 8 9 59 18

16 11 55 45

h m s

5 21 37*5
5 17 28-7
5 13 330

O 1 II

84 24 55

85 47 53

86 35 55

Mr. Adams had previously computed the orbit by the method of
Olbers, on the supposition of its being a parabola, but he found that
the middle observation was so badly represented, that this hypothesis
could not be correct. He then proceeded to determine the elements
without making any hypothesis as to the conic section, and the re-
sulting elements are as follows : —

Perihelion passage, 1843, October 26d,33 Greenwich mean time.

o /

Longitude of perihelion on the orbit... 54 27*8 \ From the equinox

Longitude of ascending node 207 38*0/ of Dec. 5.

Inclination to the ecliptic 10 48*9

Perihelion distance 1*687

Semi-axis major 3*444

Eccentricity 0*510

Periodic time 6*39 sidereal years.

Motion direct.

The author suggests that the comet may, perhaps, not have been
moving long in its present orbit, and that, as in the case of the comet
of 1770, we are indebted to the action of Jupiter for its present ap-
parition. In fact, supposing the above elements to be correct, the
aphelion distance is very nearly equal to the distance of Jupiter from
the sun : also the time of the comet's being in aphelion was 1843*8
— 3*2 = 1840*6, at which time its heliocentric longitude was 234°#5
nearly, and the longitude of Jupiter was 231°*5 ; and, therefore,
since the inclination to the plane of Jupiter's orbit is also small, the
comet must have been very near Jupiter, when in aphelion, and
must have suffered very great perturbations, which may have ma-
terially changed the nature of its orbit.

VII. Observations of the Comet of Faye. By C. Rumker, Esq.
Communicated by Dr. Lee. These will be found in the Monthly
Notices, as already referred to.

VIII. Observations of the Comet of Faye, made at Starfield. By
W. Lassell, Esq.

The author thinks that the observations given may be relied upon
to within one second of time, and eight or ten seconds of declination.
They were made with the 9-feet equatorial, used differentially, com-
paring the place of the comet with the stars 23 and 30 Orionis, and
one or two small stars near them.

The following are the resulting places : —

522

Royal Astronomical Society.

Mean time of obser-

Apparent right

Apparent decli-

vation.

ascension.

nation.

1843. h m

h m ■

Dec. 12 9 57

5 15 29-1

+3 44 46-4

13 10 30

5 14 597

3 39 1-6

14 10 58

5 14 307

3 33 380

22 10 38

5 10 560

3 5 250

IX. The following Communications respecting the great Comet
of 1843*:—

1. Observations of the Comet, made by J. Burdwood, Esq.,
Master of H. M. Sloop Persian. Communicated by G. B. Airy, Esq.

The comet was seen very distinctly for several successive evenings
in March, while the vessel was cruising off the western coast of
Africa, between 0° 40' east, and 0° 13' west longitude; and be-
tween 5° 10' and 5° 30' north latitude. The following distances
were observed with the sextant on the evening of March 7, at
7h 10m p.m. :—

Distance from Alclebaran 60 29

Canopus 75 57

Sirius 84 0

Length of tail 27 25

2. Remarks on the Comet, as seen on Board the Lawrence, of
Liverpool, on her passage from Sidney to Conception. By a Pas-
senger. Communicated by W. Simms, Esq.

The comet was first seen on the 1st of March, at 8^ p.m., as a
white streak of light, inclined at an angle of 40° to the horizon, and
was imagined to be the zodiacal light. It was again seen on the 6th,
when the tail was 50° in length, in two streams of light, the outside
edges being clear and well-defined. On the 9th, the nucleus was
seen, and appeared as bright as stars of the third or fourth magni-
tude. It was seen at intervals till the 28th of March.

3. Abstract of an article in Silliman's Journal, containing au Ac-
count of Observations of the great Comet, made near the time of its
Perihelion Passage. By J. G. Clarke, Esq., of Portland.

Mr. Clarke measured the distance of the nucleus from the sun on
the 28th of February, and states, that the nucleus and every part of
the tail, as seen by him in strong sunshine, were as well defined as
the moon on a clear day, and resembled a perfectly pure white cloud,
without any variation, except a slight change near the head, just
sufficient to distinguish the nucleus from the tail at that point. The
denseness of the nucleus was so great that Mr. Clarke has no doubt
that it might have been visible upon the sun's disc, if it had passed
between it and the observer. This apparent density he attributes to
the foreshortening of the tail, and its being so directed to the earth
that the nucleus must have been seen through a considerable mass

* Preceding communications respecting this comet have appeared in
the present volume, p. 300.

Royal Astronomical Society. 523

of the matter of the tail. The following distances were measured
with a reflecting instrument : —

d h m s

Feb. 28 3 2 15 p.m. Distance of sun's farthest limb from 0 . „

nearest limb of nucleus 4 6 15
... 3 6 20 ... ... sun's farthest limb from

farthest limb of nucleus 4 7 30
... 3 9 40 ... ... sun's farthest limb from

extremity of tail 5 6 30

Mr. Clarke supposes the first of these measures to be correct
within 15"; the other two are given as near approximations. Al-
lowance must, of course, be made for the motion of the two bodies
during the time of observation. When the sun was on the meridian,
the angle made by the line joining the centres of the sun and the
nucleus with the lower vertical, on the eastern side, was about
seventy-three degrees.

X. On the Deducing of the Parallax of Mars, and hence that of
the Sun from the Geocentric Motion of the former when in opposi-
tion, and especially when near the Node of his Orbit. By S. M.
Drach, Esq.

The author, after alluding to the method of determining the solar
parallax from observations of the transits of the inferior planets over
the sun's disc, states his method as follows : —

" The counterpart of the above is the simultaneous observation at
different points of the earth's surface, of the time occupied by a su-
perior planet, when near opposition and near the node, in passing
through a certain interval of space, say about half a degree (the sun's
diameter) ; but as this happens at night, comparison stars are to be
used, and the interval assumed to be nearly equivalent to their di-
stance. Thus, e. g., if Mars be the object observed, and at Green-
wich x minutes are occupied by it in describing an arc which it re-
quires only y minutes to describe at the Cape of Good Hope, then
will the difference x— y, properly applied, give the parallax of Mars,
and hence that of the sun."

XL A Letter from Sir J. F. W. Herschel, Bart., to Mr. Baily,
dated 6th Sept., 1842, on the Increase in Magnitude of the Star tj
CygnL

"I beg to call your attention to the star ij Cygni (21 Cygni,
Fl.; Piaz. xix. 344), which appears to have increased in magnitude
very considerably since the date of Piazzi's observations. It is now
the principal star in the neck of the Swan, and of nearly the fourth
magnitude, — very conspicuous to the naked eye, and marking, in
fact, the only very distinctly seizable point between Albireo in the
beak, and the bright star y in the body. Now, Piazzi, from nineteen
observations in right ascension, and eleven in declination, sets it
down as of the 5*6 mag. It does not occur in the Astronomical
Society's Catalogue. The star bq Cygni, which does occur in that
Catalogue, is there set down as of the 5th mag., which is also what I
make it, or rather above than under ; but ij is now a much more di-
stinguished star.

524 Royal Astronomical Society: Anniversary ', 1844.

" I may also take this opportunity to mention that the star 34
Cygni, the celebrated variable star discovered by Janson in 1600,
whose period is 18 years, is now at or near its maximum; at least,
it is a star of full the 5th mag. and very nearly equal to A2 and bs.

" Bode, on the authority of Lalande, has placed in his maps a star
of the 4th mag., with the letter i attached, near i) Lyrse. I can find
no star in the place laid down visible in an opera-glass. It is the
star 153 Lyrae, of Bode's Catalogue.

" I cannot but suspect several other stars in this constellation of
variation ; at least, I find the greatest discordance between the actual
aspect of many regions within its extent and the magnitudes as laid
down by Bode. Harding's maps, however, agree better. In Har-
ding's, however, 13 is marked of the same magnitude with b'K"

February 9, 1844. — Extracts from the Report of the Council of the
Society to the Twenty -fourth Annual General Meeting.

The Council always regret when they have cause to announce the
decease of any of the Fellows or Associates of the Society. On the
present occasion they have to lament the death of seven of their
number : namely, His Royal Highness the Duke of Sussex, Professor
Wallace, Mr. William Allen, and Mr. Arnold, on the home list ;
and Messrs. Bouvard, Cacciatore and Hassler, amongst the asso-
ciates.

His Royal Highness Augustus Frederick, Duke of Sussex, K.G.
&c. departed this life on the 22nd of last April, in his seventy-first
year. He was the sixth son of George III. and early devoted his
mind to intellectual culture, passing a more than respectable career
in the University of Gottingen. Hence his learning and accom-
plishments were very considerable ; and what might be deficient in
profundity was compensated by strong perceptive faculties. He was
of independent opinions, and unwearied in his advocacy of civil and
religious liberty. For nearly half a century he was the persevering
and zealous patron of every really charitable institution, every use-
ful scheme, and every benevolent project. When the late Mr. Da-
vidson left our shores for the dangers of a journey to Timbuctoo,
" Bring this gentleman safely home again," said the Duke to Abou
Bekr, the Negro companion, " and you shall have an asylum in this
palace for the rest of your life."

As President of the Society of Arts, he was remarkable for the
suavity and appropriate addresses with which he distributed the
adjudicated prizes ; and his eight years' presidency of the Royal
Society was conducted with such general satisfaction, that his re-
signation was received with unfeigned regret. His extensive ac-
quaintance with scientific and literary men, native and foreign, ma-
nifested a decided natural taste for their pursuits, and a just appre-
ciation of their value. In his intercourse with the Fellows, he was
kind and attentive without ostentation, and affable without conde-
scension.

Although his means were by no means commensurate with his
high station, his Royal Highness collected a splendid library, rich in

Obituary : the Duke of Sussex, William Allen. 525

every department of science and learning, and unexcelled in its
biblical department. He enjoyed, in a high degree, the respect and
regard of the British public ; and this feeling was shared even by
those who differed most strongly from the views which guided his
course in political affairs. His, however, were hardly to be called
political leanings, for his liberal aspirations emanated from a truly
benevolent heart, wishing to promote the physical comfort and men-
tal improvement of his fellow- creatures.

The cause of humanity has also experienced another serious loss
in the death of Mr. William Allen, a member of the Society of
Friends, President of the Pharmaceutical Society, and one of the
original Members of this Society. This gentleman was born on the
19th of August, 1776, in London, and soon entered upon the useful
profession of Chemistry, In this branch of knowledge he made
such advances as to be identified with its scientific progress ; and
he became a distinguished Professor of Experimental Philosophy at
Guy's Hospital, and the Royal Institution of Great Britain. He was
connected with some of the nicest experiments of the day, in con-
junction with Davy, Babington, Marcet, Luke Howard, and Dalton.
Together with Mr. Pepys, he made the well-known investigations
upon atmospheric air, and other gases, which are recorded in the
Philosophical Transactions ; and in which he proved the identity of
the diamond with charcoal*.

What, however, distinguished him here, was his taste for astro-
nomy, as evinced by his elegant private observations, and his ex-
tensive astronomical library. In 1815 he published a neat little
work, intituled " A Companion to the Transit Instrument : " it con-
tains all the stars, from the first to the fourth magnitudes, together
with the places of some of the most interesting of the double stars,
and a few nebulae.

Mr. Allen united, in a remarkable degree, sound knowledge, sua-
vity of manneis, and sterling principle ; and he deservedly possessed
the esteem of all who knew him. He pursued his views with per-
severing industry ; and travelled far and near in his search after the
means of advancing the moral and religious education of the poor.
He died on the 30th of last December, at Lindfield in Sussex, a scene
of his zealous benevolence ; for it was here that he endeavoured to
show how much aid might be afforded to the work of education by
the earnings of the scholars : and, with co-operation, he founded a
colony of labourers in that neighbourhood, to whom he allotted land
at a remunerating but easy rent, in order to improve their moral and
physical condition.

Such was William Allen, whose life was devoted to the best in-
terests of mankind, and whose name is known wherever the efforts
of humanity are in activity.

Professor Niccolo Cacciatore was born at Castel-termine in the
southern part of Sicily, of respectable parentage, on the 26th of
January, 1770. In his boyhood he was educated by his paternal
uncle, a Professor of Theology in Girgenti. At the age of 1 7 years

[* Messrs. Allen and Pepys's papers here alluded to will also be found in
Phil. Mag. First Series, vol. xxix. p. 216 ; xxxii. p. 242 ; and xxxiv. p. 379.]

526 Royal Astronomical Society i Anniversary, 1844.

he went to Palermo, and, under the care of the Canon De Cosmis,
his townsman, he devoted himself to the study of Greek and the
belles lettres. He then proceeded to study mathematics and the
physical sciences without the assistance of a master. Piazzi became
acquainted with him in the house of De Cosmis, and, surprised at
his progress, took him to the Observatory to perfect him in his fa-
vourite study, and has made favourable mention of him in the preface
to the Palermo Catalogue. In September 1798, he went to reside
entirely with Piazzi, and there occupied himself exclusively with as-
tronomy, so that, in 1800, he was appointed assistant at the Royal
Observatory, and assisted in completing Piazzi's great Catalogue
above-mentioned.

During the years 1803, 4 and 5, he repeated the observations on
Maskelyne's 36 fundamental stars, which labour was published in
the Sixth Book of the Royal Observatory of Palermo. On these re-
sults Piazzi wished to found a new catalogue, but suffered so much
in his eyes in 1807, that he confided it to Cacciatore, and the work
was published in 1814 ; on which he was honoured with Lalande's
gold medal from the Royal Institute of France.

In 1810 he had been elected general examiner of the Corpi
Facoltativi of Sicily, with the charge of instructing, in the higher
geodesy, the officers of the Topographical Office. In 1814 he was
declared honorary professor in the Royal University. In 1817,
Piazzi being called to Naples to direct the new Observatory there,
Cacciatore was promoted to the direction of the Royal Observatory
at Palermo. In 1819 accordingly, his observations and calculations
of the fine comet of that year were published in his name.

But, in 1820, whilst he was assiduously prosecuting his researches
on the proper motion of the stars, and on the thermometric cause
of the observed difference of the obliquity of the ecliptic between
summer and winter, the revolution occurred ; when his house was
pillaged, as well as the library of the Observatory, although in the
Royal Palace ; so that he lost everything, even his manuscripts being
partly carried off or destroyed. In trying to save the Observatory
he with difficulty saved his life, being with the greatest indignity
thrust into prison. Yet in December of the same year he was de-
puted, as representative of Palermo, to the Parliament at Naples.
He was elected an Associate of the Royal Astronomical Society of
London, and was one of the 40 Associates of the Italian Society
established in Modena. He was general secretary of the Academy
of Sciences in Palermo, which he improved by introducing appro-
priate regulations.

In 1810 he married Emmanuela Martini, by whom he had five
children. He had long felt a chronical affection of the brain, and
finally suffered so much from the cholera that he was obliged to give
up his astronomical labours, though he lingered until the 28th of
January, 1841, when at two in the morning he expired in the arms
of his wife and children. His son, Gaetano Cacciatore, is appointed
his successor in the Observatory*.

* See further accounts of Niccolo Cacciatore in the Annali Civili of Sicily,
No. 49, for January and February 1841, page 72.

Obituary : M. Cacciatore, Professor Wallace. 527

The following is a list of his published works : —

On the Comet of 1807.

On the Comet of 1819.

New Reflecting Circle of Simonoff, 1824.

Geognostic Observations on Monte Cuccio, 1824.

Geognostic Researches on Monte Cuccio, 1825.

Letter to Zach on Terrestrial Refractions, &c, 1825.

On Meteorology, 1825.

A Discourse on the Origin of the Solar System, 1826.

Letter to Visconti on some errors in Piazzi's Catalogue, 1827.

On the Barometric Rise in January 1828, in a Letter to
Ferrusac.

Observations on Monte Cuccio, 1828.

Mineral Baths of Sclafani, 1828.

On Comparative Meteorology, in Latin, 1832.

Ditto in Italian, 1832.

On the Summer Heat of Palermo, 1833.

On the Sirocco at Palermo, 1833.

Difference of Longitude between Naples and Palermo, 1834.

On the Expected Return of Halley's Comet, 1835.

On Goniometry and Spherical Trigonometry, 1837.

On the Solar Spots, 1839.

Besides various articles in Periodicals and Scientific Corre-
spondences.
William Wallace, LL.D., late Professor of Mathematics in the
University of Edinburgh, was descended from a family in humble
circumstances, which had been settled, for some generations, at
the village of Kilconquhar in Fifeshire. His grandfather inherited
a small property, the greater part of which he lost through injudi-
cious management. His father established himself at Dysart, a sea-
coast burgh in Fife, as a manufacturer of leather and shoes for ex-
portation, and for some years carried on a considerable trade, which,
however, was ruined by the breaking out of the American war. The
subject of this memoir was born at Dysart on the 23rd of September,
1768, and was the eldest of a numerous family.

In adverting to the circumstances of his early life, he used to re-
late that the first rudiments of his education were received from an
aged widow in the town, who kept a school for children, and retailed
small wares. About the age of seven he was removed to a school
of a better class, in which the principal branch of instruction was
arithmetic. In this science, however, he had already been grounded
by his father, and had made considerable proficiency in it before he
was advanced to that department in the routine of his school pro-
gress. His attendance at school — for instruction it can scarcely be
called — was discontinued when he had reached the age of ten or
eleven years ; and, according to his own statement, all he owed to
the schoolmaster was the power of reading, and of forming, in a very
indifferent way, characters by writing. His knowledge of arith-
metic he owed to his father, and to his own strong liking for the
subject.

528 Royal Astronomical Society \ Anniversary, 1844.

In 1784, when in his sixteenth year, he was sent to Edinburgh to
learn the trade of a bookbinder ; and after a year or two of probation
he entered upon a regular apprenticeship to this craft. But his pas-
sion for the acquisition of knowledge had been thoroughly roused
by the perusal of some books which had fallen in his way ; and,
during the period of his apprenticeship, he devoted every spare mo-
ment to reading. These moments were, however, few. His master
happened to be a person who had no sympathy with literary tastes,
and no other concern about his apprentices than how to extract
from them the greatest amount of labour. But his father, a man of
considerable intelligence and strict religious principles, having re-
moved with his family to Edinburgh, he had the comfort of residing,
during this period, in the house of his parents, and the advantage of
their society, encouragement and moral superintendence, to which
he professed himself to have been greatly indebted. His occupation,
also, was in some respects favourable to the gratification of his
tastes. Books of science were constantly passing through his hands,
and his curiosity could not be restrained from occasionally casting a
glance at their contents. He had also acquired a few mathematical
books of his own ; and such were his ardour and enthusiasm in their
study, that it was his constant practice to take his meals with one
of them in his hand, and to carry one in his pocket, to read on his
way to and from the workshop. By this assiduous application, be-
fore he reached the age of twenty, he had read and made himself
master of Cunn's Euclid, Itonayne's Algebra, Wright's Trigono-
metry, Wilson's Navigation, Emerson's Fluxions, Robertson's Trans-
lation of La Hire's Conic Sections, and Keill's Astronomy. Of these
books he cherished the remembrance, as the means by which he had
been enabled to grope his way into the region of the mathematics.

Hitherto, Mr. Wallace's efforts to acquire knowledge had been
made under the most disadvantageous circumstances : without sym-
pathy from any one but his father, and without a companion or friend
to appreciate his exertions or applaud his success. But he was now
approaching the turning-point of his fortunes. He happened to be-
come acquainted with an elderly person, a carpenter by occupation,
who was employed by the celebrated Dr. John Robison, the Pro-
fessor of Natural Philosophy, as an assistant in his class experiments.
This man, though a great reader of books, was no mathematician ;
but he had sat too near the feet of Gamaliel not to have imbibed a
respect for the science, and for the pursuits of his young friend.
With an excusable vanity, he was in the habit of boasting of his in-
timacy with the Professor, to whom he proposed to introduce Mr.
Wallace. The latter, however, with great good sense, declined the
kindly meant offer until the term of his apprenticeship had expired,
when, though still with some diffidence and hesitation, he was pre-
vailed upon to take advantage of it. Armed with a letter from his
humble patron, he waited upon the Professor, who received him with
great kindness, examined him with respect to his proficiency in geo-
metry and the conic sections, and inquired into the circumstances of
his life, and the means by which he had made so much progress in the

Obituary : Professor Wallace. 529

mathematics. In the course of the conversation Dr. Robison con-
siderately took occasion to warn him that the study of mathematics
was not likely to lead to anything advantageous in the world : the
reply was, that he was aware of the fact ; but being, as it seemed,
doomed to a life of labour, he hoped to sweeten the cup by the plea-
sure to be derived from the possession of knowledge. The interview
ended with an invitation from the Professor to attend the course of
lectures on Natural Philosophy then about to begin. Sensible as
he was of the advantages which he could not fail to derive from such
instruction, it required no small sacrifice on his part to accept the
offer ; for, being then employed as a journeyman, the time thus oc-
cupied could only be commanded by the abstraction of an equal por-
tion from his hours of rest or sleep. Every difficulty, however, gave
way before a determined will. The class was diligently attended ;
and he has been heard to say, that if he were asked which had been
the happiest period of his existence, he would refer to that at which
he attended the lectures on natural philosophy, when, for the first
time in his life, he had the means of receiving sound instruction, and
found himself in the company of young men devoted to the pursuit
of knowledge.

Dr. Robison's next act of kindness was to introduce him to his
colleague, Mr. Playfair, the Professor of Mathematics. Mr. Playfair
was no less struck with the extent of his acquirements, and likewise
offered him admission to the mathematical class ; but attendance
on two classes in one day being, in his circumstances, entirely out
of the question, he was under the necessity of declining the offer,
much, it may readily be believed, to his regret. Mr. Playfair, how-
ever, from this first interview, took a warm interest in his welfare,
advised him with respect to the course of reading he should follow,
supplied him with books from his own library, and continued his
steadfast friend through life.

These details may appear trivial, or unnecessarily minute ; but it
can never be wholly uninteresting to trace the steps by which di-
stinction in science or literature has been obtained when opposed by
obstacles which might seem, and in ordinary cases prove to be, in-
surmountable. To the individual we are commemorating they were
all-important : some may receive encouragement from his example ;
and science itself is placed in an advantageous light when we see
men so eminent as Professors Robison and Playfair taking trouble
with, and giving help and encouragement to, a friendless young
man, who had no claim on their good offices, and no other recom-
mendation to them, than his successful struggles in acquiring the
elements of those sciences which they themselves cultivated with such
distinguished success. On the other hand, the merit must have been
of no ordinary kind which, to persons of their experience, appeared
so remarkable.

About the time he was attending Dr. Robison's lectures he was
induced, by the prospect of having the command of a greater portion
of time than had yet been at his disposal, to exchange his occu-
pation for that of warehouseman in a printing-office. While in this

Phil. Mag. S. 3. No. 162. Suppl. Vol. 24. 2 M

530 Royal Astronomical Society : Anniversary, 1844.

occupation Dr. Robison paid him a visit, and proposed to him to give
private lessons in geometry to one of his pupils. This proposal
opened up a new prospect to him, and admitted the first gleam of
hope of his being able to emancipate himself from the drudgery of
manual labour. He now also began to acquire a knowledge of Latin,
and in this, as in the study of mathematics, his manner of turn-
ing time and opportunity to account may afford encouragement to
those who are in pursuit of knowledge under difficulties. A part of
his duty in the printing-office was to collect the successive sheets of
a work from a series of heaps arranged round a circuit of tables.
While engaged in this monotonous occupation, he fixed up upon
the wall a Latin vocabulary, from which he committed to memory
a certain number of words every time he passed it in making his
round. In his study of Latin, however, he received assistance
from a student, to whom, in return, he gave instruction in mathe-
matics.

After he had been engaged a few months in the printing-office,
he entered into the employment of one of the principal booksellers
of Edinburgh in the capacity of shopman. This change was advan-
tageous in several respects. His circumstances were now consider-
ably improved, and he found leisure, not only to pursue his favour-
ite studies, but to increase his stock of knowledge by general read-
ing, and even to give private lessons in mathematics in the evenings.
While in this situation he contrived to get a few lessons in French,
and commenced his acquaintance with the works of the continental
mathematicians.

In 1793, while in his twenty- fifth year, he took the resolution to
give up his employment, and support himself by teaching mathema-
tics privately. This plan probably succeeded to the full extent of
his moderate expectations. He now attended a course of lectures
by Professor Playfair ; and although, as the course was intended for
an audience far behind him in mathematical acquirements, he had
little to learn, the example of Playfair's manner — dignified, eloquent,
and impressive, in a degree rarely equalled — was of great use to him
in after-life. At the same time he also attended a course of che-
mistry, and by assiduous diligence endeavoured to repair, to the ut-
most of his power, the deficiencies of his early education.

In 1794, Mr. Wallace, on the recommendation of Professor Play-
fair, was appointed to the office of assistant teacher of mathematics
in the academy at Perth. In respect of emolument the appointment
was of no great value, but it gave him a settlement in life, with rea-
sonable leisure to prosecute his mathematical studies, of which he
did not fail to take advantage. In 1796 he presented his first me-
moir to the Royal Society of Edinburgh, entitled, " Some Geome-
trical Porisms, with Examples of their Application to the Solution
of Problems." This paper, which contained some new and curious
porismatic propositions, afforded ample proof of original and invent-
ive powers ; while his manner of conducting the investigation
showed how accurately he had imbibed the spirit and methods of the
ancient geometrical analysis. About the same time, on the request

Obituary. Professor Wallace. 531

of Dr. Robison, he contributed the article " Porism" to the third
edition of the Encyclopaedia Britannica ; and, a few years later, when
a new and greatly enlarged edition of that work was undertaken, he
was enlisted as a regular contributor, and undertook to furnish the
principal mathematical papers.

During the vacations of the Perth academy he paid regular visits
to Edinburgh, where he continued to cultivate the friendship of Ro-
bison, Playfair, and other scientific men, to whom his now recognised
talents and mathematical attainments procured him introductions.
The first mark of literary distinction he received was that of Cor-
responding Member of the Edinburgh Academy of Physics ; a so-
ciety which, though not known by its published transactions, was at
that time remarkable by reason of the cluster of talented persons of
whom it was composed, several of whom have since attained the
highest distinction in literature, philosophy, and public affairs.
Such association could not fail to have a powerful effect in the de-
velopment of his mind, even though his residence at a distance from
Edinburgh prevented him from attending many of the meetings.

In 1802 he presented a second paper to the Royal Society of
Edinburgh, containing a new method of expressing the coefficients
of the development of the algebraic formula which represents the
disturbing effect of the mutual action of two planets on each other.
This was a contribution of great merit, and, immediately upon its
publication, established his reputation as a mathematician of the first
order. The volume of the Transactions in which it appeared was
reviewed in the second number of the Edinburgh Review ; and an
able analysis of Mr. Wallace's paper was concluded with the follow-
ing encomium : — " We cannot conclude without expressing our sin-
cere admiration of this excellent performance — excellent in every
respect ; and, trifling as it may appear to mathematicians, remark-
able for a pure, perspicuous, and not inelegant style. It is a paper,
equal, in our opinion, to whatever has been most admired of the
greatest analysts. We remember nothing in the works of Euler or
Lagrange which belongs to a higher order of excellence in the
science." Mr. Wallace's method of development depended ulti-
mately upon the proportions which the perimeters of two ellipses
bear to those of their circumscribing circles ; and in order to faci-
litate its application, he gave, in an appendix, a very beautiful and
quickly converging series for the rectification of the ellipse, applica-
ble to every case of eccentricity, and to every length of an arc that
can possibly occur in calculation. His merit with respect to this
paper cannot be considered as having been diminished by the disco-
very he made some time after its publication, that in certain respects
he had been anticipated by Legendre. The very little intercourse
which at that time existed between this country and France, and the
position of the author in a remote provincial town, are sufficient ex-
cuses for his not having been more accurately acquainted with the
state of mathematical discovery on the Continent.

Mr. Wallace had been for several years a contributor to some of
the periodical publications in England in which mathematical ques-

2M2

532 Royal Astronomical Society : Anniversary, 1 844.

tions were proposed, as Leybourn's Repository, the Gentleman's Ma-
thematical Companion, and others of the same class. To this circum-
stance he attributed an incident which had an important influence
on his future life. In 1803, he received a letter, under a feigned
name, in which he was informed that an instructor in mathematics
was wanted for the Royal Military College, then established at Great
Marlow ha Buckinghamshire, and recommended, if he thought of
being a candidate for the office, to make an immediate application.
Inquiry being made in the proper quarter, the information was found
to be correct, but he ascertained also that it would be necessaiy to
make his application in person. In matters affecting his own inter-
ests the disposition of his mind was not sanguine ; and, as in the
present case he had no influence to employ, and no other recommen-
dation to carry with him than his skill in mathematics, his chances
of success appeared so small that he would have been deterred by
the length and inconveniences of the journey from thinking more of
the subject, had he not been encouraged by his friend Professor
Playfair. On his arrival at the Military College he found there were
several competitors ; but the persons who had to decide on the re-
spective qualifications of the candidates gave their decision in his
favour, and he was accordingly appointed to the office.

Mr. Wallace held this appointment upwards of sixteen years,
during which period the whole of his leisure time was unremittingly
devoted to scientific study and literary labour, the fruits of which
appear chiefly in his numerous contributions to the two great En-
cyclopaedias then publishing in Edinburgh. This species of writing,
which is not particularly well adapted to form the basis of a perma-
nent reputation, was in a manner forced upon him by the circum-
stances of his position. On his appointment to the Perth Academy
he had married, and after he joined the Military College his family
began to increase rapidly. The inconveniences he had suffered from
the defects of his own early education rendered him only more soli-
citous that his children should not labour under any disadvantages
in this respect, and, as they grew up, he placed them at schools in
Edinburgh. His official income being insufficient for this expense,
he was led to engage in the works now referred to, rather with a
view to add to his means, and to enable him to discharge a sacred
duty, than for the sake of any distinction he was likely to get by
them. No individual, perhaps, was ever less influenced by consi-
derations of a worldly nature, or more ready to bestow time and la-
bour upon objects from which he could neither receive nor expect any
remuneration whatever.

In 1808 he contributed a paper to the Royal Society of Edin-
burgh, entitled " New Series for the Quadrature of the Conic Sec-
tions, and the Computation of Logarithms," and containing some
very remarkable formula; for the rectification of circular arcs, with
analogous expressions for the sectors of the equilateral hyperbola and
the logarithms of numbers ; all deduced from elementary principles,
and without the use of the differential calculus or any equivalent
method. At the time the paper was published, he believed the se-

Obituary : Professor Wallace. 535

ries to be entirely new, but he discovered afterwards that some of
them had been previously given by Euler.

Mr. Wallace's services at the Military College were held in
great estimation by the superior officers, who frequently availed
themselves of his practical sagacity in the adoption of regulations
having respect not only to the course of instruction, but the general
management of the establishment. One of the results of this defe-
rence to his recommendations (more particularly interesting to the
Society), is the small observatory attached to the College, for the in-
struction of the officers of the senior department in practical astro-
nomy. The plan of the building was originally furnished by Dr.
Robertson of Oxford ; but the superintendence and arrangement of
all the details of construction were confided to Mr. Wallace, who
visited most of the observatories in the neighbourhood of London,
for the purpose of acquiring hints and information . A transit-instru-
ment, an astronomical circle by Ramsden, a reflecting circle, and a
clock by Hardy, were procured, and some other instruments were
ordered, but countermanded from an apprehension of opposition to
the estimates in the House of Commons. Although an observatory
of this kind cannot be expected to produce results of any direct ad-
vantage to astronomy in the present state of the science, it must still
be regarded as no unimportant appendage to a national establish-
ment for the instruction of officers for the public service.

In 1819a vacancy occurred in the Mathematical Chair of the Uni-
versity of Edinburgh, through the death of Professor Playfair, and
the appointment of Mr. Leslie to succeed him in that of Natural
Philosophy, and Mr. Wallace resolved on presenting himself as a
candidate. The patronage belongs to the magistrates of the city,
who, having in general no pretensions to be capable of estimating
degrees of merit in abstract science, necessarily form their opinions
from the testimony of others, or notions of general fitness, and are
liable to be acted upon by influences of various kinds. In the pre-
sent case a very keen contest took place ; for another competitor (a
man of general talent and great respectability, though unknown as
a mathematician) was strenuously supported by a strong political
party. The struggle terminated, however, in his election by a large
majority of the voters. This was the crowning object of his ambi-
tion. Ever since his appointment to the Perth Academy, he had
fixed his regards on a professorship in a Scottish university as the
goal of all his exertions ; but his elevation to the Chair of the Gre-
gorys, of Maclaurin, Matthew Stewart, and Playfair, probably did
not enter at that period into his most sanguine anticipations.

Mr. Wallace had reached the age of fifty-one when he was ap-
pointed to the mathematical professorship in Edinburgh ; but he still
retained both mentally and bodily all the energy and activity of his
younger years. He held the office till 1838, when he resigned on
account of ill-health, having been unable to perform his duties in
person during the three previous sessions. Upon his resignation
the honorary title of Doctor of Laws was conferred upon him by the
University, and at the same time he received a pension from Govern-

534? Royal Astronomical Society: Anniversary, 1844.

ment which he enjoyed during the few remaining years of his life,
in consideration, as the warrant stated, of his attainments in science
and literature, and his valuable services, up to a very advanced pe-
riod of life, first in the Military College, and afterwards at the Uni-
versity of Edinburgh.

For some years after his establishment at Edinburgh, a consider-
able portion of his time was occupied in the preparation of his lec-
tures, on which he bestowed great pains. When the new edition
of the Encyclopaedia Britannica was commenced, he undertook the
revision of all the mathematical papers he had contributed, as well
as some of those which had been written by Dr. Robison ; and se-
veral of the more important treatises, particularly Algebra, Conic
Sections and Fluxions, were remodelled and almost entirely re-
written. To the Transactions of the Royal Society of Edinburgh he
contributed a paper in 1823, on the Investigation of Formulae for
finding the logarithms of trigonometrical quantities from one another;
one in 1831, entitled "Account of the Invention of the Pantograph,
and a Description of the Eidograph ;" and one in 1839, on the Analo-
gous Properties of Elliptic and Hyperbolic Sectors. His last contri-
bution to that Society, published in vol. xiv. of the Transactions,
was entitled, " Solution of a Functional Equation, with its Applica-
tion to the Parallelogram of Forces, and to Curves of Equilibration."
This paper, in addition to the investigation of series adapted for cal-
culation, contains a set of tables, to ten decimal places, of the cor-
responding values of the amplitude, ordinate, and arc of a catenary,
which are important in an engineering point of view, as they afford
the data required for constructing arches having the forms of equili-
brated curves. Similar tables, to eight places, had previously been
given by Mr. Davies Gilbert in a paper on the mathematical theory
of suspension bridges, in the Philosophical Transactions for 1826 ; but
the numbers were found by Mr. Wallace to be erroneous, generally,
in the last three decimal figures.

Mr. Wallace is the author of a paper in vol. ix. of our Memoirs
containing two elementary solutions of Kepler's problem by the an-
gular calculus. In the Transactions of the Philosophical Society of
Cambridge, vol. vi., there is also a paper by him under the title of
" Geometrical Theorems and Formulas particularly applicable to some
Geodetical Problems." For this subject he had a particular predi-
lection ; and in 1838, while confined to a sick-bed, he composed,
and afterwards published at his own expense, a separate work, enti-
tled " Geometrical Theorems and Analytical Formulae, with their
application to the Solution of certain Geodetical Problems." This
volume, which he appropriately dedicated to his friend Colonel Colby,
contains the substance of his paper in the Cambridge Philosophical
Transactions, with the addition of a considerable number of extremely
elegant formulae, most of them new, and some of them important in
the practice of the higher geodesy.

Professor Wallace took great delight in all the practical ajDplica-
tions of his science, and had a strong turn for mechanical invention.
His attention having been directed to the imperfections of the Pan-

Obituary. Professor Wallace. 535

tograph, he invented, in 1821, an instrument on a different principle
to supply its place, to which he gave the name of Eidograph. This
instrument answers the same purposes as the common pantograph, to
which, however, it is greatly superior, both in the extent of its ap-
plications and the accuracy of its performance ; for while the simi-
larity of the copy to the original, in all its parts, is preserved with
geometrical accuracy, the copy may be reduced or enlarged in almost
any proportion ; or, by a particular modification of the instrument,
it may even be reversed, and transferred immediately to metal or
stone. This ingenious instrument, which would seem to be admirably
adapted to the purposes of the engraver, was first described by him
in vol. xiii. of the Edinburgh Transactions, to which reference has
already been made. He has also described, in the Appendix to his
Conic Sections, an Elliptograph, or instrument for describing an
ellipse by continued motion, founded on a very beautiful property of
the ellipse first pointed out, we believe, by him, namely, that the
curve is organically described by any given point (not in the circum-
ference) in the plane of a circle which rolls along the concave cir-
cumference of another fixed circle, the radius of which is twice that
of the rolling circle. And in an Appendix to his Geometrical Theo-
rems he has given the description of an instrument which he invented
for the graphical solution of an important problem in surveying, viz.
to determine the position of a station, having given the angles made
by lines drawn from it to three other stations in the same plane,
whose positions are known. This instrument, which he called a
Chorograph (the problem which it solves having been proposed as a
chorographical problem by Richard Townley in No. 69 of the Philo-
sophical Transactions), is simple, compact, portable, and inexpensive ;
and in these respects has considerable advantages over the station-
pointer, generally used for the same purpose.

Among the objects connected with the advancement of science to
which Professor Wallace gave his aid, after his appointment to Edin-
burgh, there is one which it would be unpardonable to pass over
without notice in this place, — we allude to the observatory now esta-
blished there. Ever since the time of Maclaurin there had existed
a small astronomical observatory in Edinburgh, but no provision was
made for regular observation, nor, indeed, did it contain any instru-
ments fit for the purpose. Through the exertions, chiefly of Pro-
fessor Playfair, funds were at length raised, by private subscription,
for the erection of an observatory adapted for observations of the most
accurate kind. Mr. Playfair did not live to see the building completed,
or means provided for obtaining instruments, or carrying on syste-
matic observations ; but Mr. Wallace, on becoming his successor,
entered fully into his views, and, in concert with a few other indi-
viduals, used all his influence and exertions towards bringing the
scheme to maturity. At length, after years of expectation and delay,
the Government was prevailed upon to take the observatory under
its protection, furnish it with instruments of the first class, appoint
an astronomer and assistant, and provide for the regular publication
of the observations. In bringing about this arrangement, Mr.

536 Royal Astronomical Society. Anniversary, 1 84*4?.

Wallace's aid and recommendation were of essential service ; and if
anything was wanting to complete the satisfaction which he felt at
the result, it was to see the observatory placed under the care of his
friend Professor Henderson, of whose distinguished merits as an as-
tronomer it would be superfluous to speak to those who are in the
habit of attending our meetings, or reading our Memoirs.

Although the works whicli Mr. Wallace has left behind him assure
him a high place as an original and inventive mathematician, the ta-
lents with which he was endowed by nature were, doubtless, ren-
dered less productive than they would have been by his want of early
education, his residence during the best years of his life in the coun-
try at a distance from congenial society, and, perhaps, still more
from the circumstance of so much of the time which his laborious
public duties left at his disposal having been consumed in the prepara-
tion of his numerous treatises for the Encyclopaedias. These treatises
being mostly of an elementary kind, and composed for the purpose
of explaining the principles of the various branches of mathematical
science, afforded little scope for originality. They possess, however,
all the qualities which give value to the class of writings to which
they belong ; being remarkable for lucidity and precision of style,
perspicuity of arrangement, elegance of demonstration, and admira-
ble adaptation for self-instruction. The article " Conic Sections"
in the last edition of the Encyclopaedia Britannica has been translated
into Russian, and used as a text-book in some of the schools for the
instruction of naval cadets in that empire. It has also been pub-
lished as a separate work, and is one of the most elegant geometrical
treatises on the subject in existence. Some of his other articles,
besides their intrinsic value, had the accessory merit of being the
first which were published in this country on the model of the French
school, when the French mathematics were greatly superior to our
own. His article " Fluxions," in Brewster's Encyclopaedia, was the
first systematic treatise in our language in which the differential no-
tation was used. The date of the publication is 1815 ; but, as a
point of history, it may be worth remarking, that this notation had
been adopted several years previously, both by himself and his illus-
trious colleague, Mr. Ivory, in their contributions to the Mathema-
tical Repository ; and some instances of its use occur in an English
work of much older date, Harris's Lexicon Technicum.

Mr. Wallace had made himself intimately acquainted with every
department of mathematical knowledge, but the branch which he
cultivated with the greatest affection was the ancient geometrical
analysis. Of this subject he was a perfect master. His taste having
been formed by the writings of Simson, Stewart, and Playfair, lie
had an unbounded admiration of the elegance and correctness of the
Greek geometry ; and he took credit to himself for having introduced
the Elements of Euclid to the Military College, and restored them,
as a class-book, to the University of Edinburgh. Another branch
in which he excelled was the angular calculus, which he enriched
with various new series and methods of considerable importance to
the computer. All his memoirs exhibit ingenuity and fertility of in-

Obituary : Professor Wallace. 537

vention, excellent taste, and an intimate acquaintance with those parts
of analysis with which they are connected in its most improved state*.

The perspicuity and methodical arrangement which distinguish
his writings were equally conspicuous in his academical prelections.
An intimate acquaintance with the history of scientific discovery,
and the various applications of mathematical science, joined with a
thorough knowledge of the particular subject under consideration,
a retentive memory, and a ready invention, rendered his lectures
eminently instructive. They were delivered without the slightest
attempt at ornament or effect ; but they seldom failed to place the
subject before the student in a strong, clear, and full light, and were
animated with a genuine zeal for the progress of his pupils and the
advancement of his science. His Chair had been raised to a high
degree of celebrity by a long line of illustrious predecessors, and it
sustained, while occupied by him, no diminution either of efficiency
or reputation.

Professor Wallace was not more distinguished by his mental en-
dowments than for his moral virtues and private worth. In every
relation of life his conduct was exemplary. In his family and do-
mestic circle he was greatly beloved. In his general intercourse
with the world he was upright, sincere, and independent. In society,
his habitual cheerfulness and good humour, amiable manners, bene-
volent disposition, and a never-failing fund of anecdote, rendered
him a delightful companion and a universal favourite. Generous and
liberal in all his sentiments, he entertained no envy of the discoveries
of his contemporaries, no jealousy of the reputation of younger
men ; but was ready at all times to applaud and encourage merit,
wherever, and in whatever shape, it made its appearance. For such
of his pupils as manifested any remarkable capacity or application
he entertained an esteem almost amounting to affection ; and he was
always ready to use his influence, which was considerable, in order
to forward their views in life or render them any service. In every
measure affecting the public good, or the scientific renown of his
country, he took a warm interest. He was the means of procuring
a monument to be erected in Edinburgh to Napier, the celebrated
inventor of logarithms ; and the last occupation of his life was to
investigate the administration of some of the public charities of the
city.

Mr. Wallace was one of the original non-resident Fellows of this
Society. He was also a Fellow of the Royal Society of Edinburgh ;
a Corresponding Member of the Institution of Civil Engineers ; an
Honorary Member of the Cambridge Philosophical Society ; and a
few weeks before his death he was elected an Honorary Member of
the Royal Irish Academy. After an illness which had for several

[* We may now state, as an addition to the above view of the works of
Professor Wallace, that he was the author of the two papers on the ana-
lytical investigation of a formula for the relative importance of the
Boroughs, in relation to the arrangements of the Reform Bill, signed
G. V., which appeared in Phil. Mag. Second Series, vol. xi. p. 218, and Third
Series, vol. i. p. 26. — Edit. Phil. Mag.]

538 Royal Astronomical Society: Anniversary, 1844.

years prevented him from mixing in society, he died at his residence
in Edinburgh on the 28th of April, 1 843, in the seventy-fifth year of
his age, respected by all, and sincerely regretted by a wide circle of
personal friends.

The Fellows have been already informed of the resignation of
Mr. John Hartnup, the Assistant Secretary to this Society, in con-
sequence of his having been appointed Superintendent of an astro-
nomical observatory recently established at Liverpool; for which
situation Mr. Hartnup was well qualified, not only from his former
pursuits in a similar situation, but also from those habits of accuracy
and that zeal for the science which he has always shown. But,
although the Council must at all times lament the loss of an active
and intelligent officer, they congratulate the Society on having ob-
tained a successor in Mr. Richard Harris, whose able assistance, on
various occasions, at the Royal Observatory at Greenwich, has been
highly spoken of by the Astronomer Royal, and augurs well for the
benefit and advantage which the Society is likely to derive from his
cordial co-operation.

In the last annual Report, the Council stated that they had con-
sidered it advisable to alter the numerical typography, that had been
so long in general use, by a return to the adoption of the old method
of forming the Arabic figures, which had been so long laid aside.
That measure has now been fully carried into execution by the So-
ciety, and the whole of the figures in the ensuing volume of the
Memoirs will be formed in the manner suggested in that Report.
The whole of the figures also employed in printing the three large
catalogues of stars, now in the press, will consist of this new type ;
and it is hoped that these specimens of distinctness and legibility
will soon come into more general use with the public, and ultimately
tend to drive out the uncouth and scarcely legible figures that have
so long encumbered and deformed our numerical tables.

Since the last annual Report, the Council have had the gratifica-
tion of accepting, on the part of the Society, and incorporating with
the Memoirs, Mr. Baily's volume of Catalogues, containing the
labours of Ptolemy, Ulugh Beigh, Tycho Brahe, and Hevelius, in
that department of astronomy. This volume, as the Fellows are
aware, is entirely the work of Mr. Baily, and is printed at his ex-
pense. The Council, in announcing this new obligation of the So-
ciety to Mr. Baily, feel that they only just need to remind the
meeting, that the munificence of the present, in a pecuniary point
of view, gratefully as it should be acknowledged, is not the point
to which our acknowledgements should be most specially directed.
Though the saving of expense has certainly prevented an unusual
pressure on the Society's funds (for the Council would have felt
bound to publish so valuable a communication, presented in the
ordinary way), yet the state of the accounts which you have heard
read today shows that the pressure would not have been unbear-
able. But the combination of knowledge and industry necessary to
face the formidable task of collating, revising, and annotating this
collection of catalogues, with perfect unity of purpose and plan, it is

Mr. Baily's volume of Catalogues of Stars. 539

not in the power of any collective body to command : had it been
so, this useful labour would not have remained unperformed so long,
notorious as was the difficulty, not only of consulting, but even
of procuring, the catalogues in question. Nor must we forget, in
connexion with this work, the edition of Flamsteed's catalogue which
appeared a few years ago, in the life of that astronomer by Mr. Baily,
who has thus given new access to the contents, new life to the
history, new correctness to the matter, of all the most celebrated
star-catalogues, from the earliest epoch of systematically recorded
observation to the time when instrumental methods and corrections
began to assume their present form. To this we must add that he
has imposed new duties upon those who write and speak about the
history of astronomy ; errors and misconceptions inevitable in those
who could only procure accounts of several of these catalogues at
second-hand, are from this time unpardonable.

During the past year nearly the whole of the terrestrial globe
(embracing the several continents of Europe, Asia, Africa, and
America) has been either gratified or alarmed at the appearance of
one of the most splendid and extraordinary comets that have ever
yet been placed on record. This comet does not seem to have been
noticed prior to the time of its perihelion passage (February 27),
but on the following day it was, in some places, seen nearly from
the time of sun-rise to sun- set, and even at mid- day with the naked
eye : a circumstance which affords the strongest proof of its great
splendour. For many subsequent days it was the object of uni-
versal attention and admiration ; and the numerous accounts of its
appearance and the various observations and remarks thereupon,
which have been received from all parts of the world, have already
been printed in the Monthly Notices of the Society. It seems to
have excited much consternation in some places, but was universally
remarked for its splendour, its velocity, and the great length of its
tail, during the whole time of its visible existence, but more espe-
cially about the time of its first appearance*.

Another comet, but not visible to the naked eye, has also recently
made its appearance, and was first discovered by M. Faye at the
Royal Observatory at Paris. Although this comet is far inferior in
splendour to the one just mentioned, it is in another respect more
interesting to the astronomer, inasmuch as it appears to be one that
performs its revolution in little more than six years ; thus adding
another of those remarkable bodies whose periodical returns may
ultimately tend to throw some light on the wonderful system of the
universe \.

In the annual Report of the Council in 1838, it was stated that
a Committee had been appointed by the British Association to wait
on the Government for the purpose of obtaining means to procure
the reduction of all the lunar observations made at the Royal Ob-
servatory at Greenwich. That application was made and cheerfully

[* Notices of the papers on this Comet which have heen read before
the Royal Astronomical and Royal Societies will be found in the present
volume, p. 300.]

[f See our present volume, pp. 519-522.]

5*0 Royal Astronomical Society : Anniversary, 1844.

responded to by the Government ; and the funds adequate for this
purpose were placed in the hands of the Astronomer Royal, by whose
active superintendence and control this important and laborious
operation has been at length brought to a close*. The results of
these computations are now almost ready for the press, and the
public will soon be gratified by the publication of a body of informa-
tion that must tend to throw considerable light on the elements of
the lunar theory, and thus exhibit one of the most splendid proofs
of the utility and advantage of this national establishment.

Connected with the same subject, and emanating in some mea-
sure therefrom, the Council are pleased in being able to announce
that the Government has also complied with the request of the
Astronomer Royal, to construct another building, attached to the
Royal Observatory, for the erection of an altitude and azimuth in-
strument, intended for the sole purpose of making a greater and a
more regular number of observations of the moon in various parts of
her orbit ; in order that all the practical means might be afforded
for obtaining a more perfect knowledge of the lunar theory. The
instrument here proposed is in some measure novel in its construc-
tion, and has been suggested by the Astronomer Royal, who antici-
pates certain advantages that are unattainable, or scarcely to be ex-
pected, in instruments of the usual form and construction. By
means of this new instrument it is proposed that on every day of
the year, when the state of the atmosphere will permit, the moon
shall be observed at convenient hours, and in every suitable posi-
tion, according to a plan suggested by the Astronomer Royal for
securing the most important results.

The following Fellows were elected Officers and Council for the
ensuing year, viz. —

President: — Francis Baily, Esq., F.R.S. — Vice-Presidents:
George BiddellAiry,Esq.,M.A.,F.R.S., Astronomer Royal : Augustus
De Morgan, Esq. ; Rev. Richard Sheepshanks, M.A., F.R.S. ; the
Right Hon. Lord Wrottesley, M.A., F.R.S. — Treasurer: George
Bishop, Esq. — Secretaries: Thomas Galloway, Esq., M.A., F.R.S. ;
Rev. Robert Main, M.A. — Foreign Secretary : Captain W.H. Smyth,
R.N., K.S.F., D.C.L., F.R.S.— Council: Samuel H. Christie, Esq.,
M.A., F.R.S. ; George Dollond, Esq., F.R.S. ; Bryan Donkin, Esq.,
F.R.S. ; Rev. George Fisher, M.A., F.R.S. ; John Lee, Esq., LL.D.,
F.R.S. ; Edward Riddle, Esq. ; Captain James Clark Ross, R.N.,
F.R.S.; William Rutherford, Esq. ; Lieut.-Colonel Edward Sabine,
F.R.S. ; Lieutenant William S. Stratford, R.N., F.R.S.

* The following correction on this subject appears in the Society's
Monthly Notices for March : —

" The Council take the earliest opportunity to correct a misstatement
in their Report to the General Meeting of February last, concerning the
reduction of the ancient Greenwich Lunar Observations at the Royal
Observatory. It is stated [as above] that ' the work has been at length
brought to a close.' This is not the case, but it is in a state of great for-
wardness ; the tabular places have been computed throughout, and the
labour of an additional year will probably complete the reduction of the ob-
servations."

[ 541 ]

ACADEMY OF NATURAL SCIENCES OF PHILADELPHIA.

Feb. 20. The following letter was read from Mr. Isaac G. Strain,
of the U. S. Navy*, Corresponding Member of the Academy, ad-
dressed to Dr. Morton as Vice President.

Rio de Janeiro, 7th December, 1843.

Knowing the interest you, as well as the other members of the
Academy, take in any subject tending to throw light upon the hi-
story of the human race, I take the liberty of giving you the synopsis
of a translation I have made of a letter addressed by Dr. Lund, of
the Royal Society of Antiquarians at Copenhagen, to the Historical
and Geographical Society of Brazil, of which he is an honorary
member.

Dr. Lund has for some time been pursuing his investigations in
the province of Minas Geraes ; and has devoted his attention parti-
cularly to the fossil remains found in the calcareous rocks of that
region. At present he is engaged in the publication of a work en-
titled, Blik paa Braziliens Dyreverden, or a view of the animal crea-
tion which inhabited Brazil immediately preceding the present state
of things. The Doctor states it to have been his wish to have pub-
lished in French ; but not being ready, he immediately communi-
cated with the Geographical Institute, with the remark, however,
that being written in a language little known, he expects to ensure
but few readers. He commences by referring to the question of the
coexistence of man with the extinct terrestrial mammiferous animals,
as a point which the naturalists of the old world have not been able
to resolve decisively ; that some few facts appear favourable to an
affirmative, but more to a negative solution ; that, though he has
had an opportunity to submit the question to a new examination in
this part of the world, he has not had proofs to arrive at a definite
result, although his labours in zoology have terminated most happily.
The geological archives of the history of our planet are found (says
the learned Doctor) in the caverns of the calcareous rocks, which
enter, as a constituent part, into the most extensive formations in
the interior of Brazil. The animals whose remains he has met, are
for the most part different from those which actually exist on the
surface, showing that they belonged to a distinct creation.

He has already examined nearly two hundred caverns. The spe-
cies of animals he has examined, of the mammiferous class alone,
number one hundred and fifteen, which much exceeds the number
now existing of this class, which he has reduced to eighty-eight.

From the mutilated state in which they were generally found, it
appears probable they owe their introduction to the beasts of prey

* Mr. Strain left the United States in the summer of last year in a Government
vessel for South America, as the head of a scientific exploring party into a portion
of the interior of that country, and which promises important and interesting re-
sults. Mr. S. goes out under the auspices of the U. S. Government, aided also by
members of this Institution and other individuals, and is amply furnished with every
requisite for the successful prosecution of his hazardous and arduous undertaking.
Since his arrival at Rio, he has also been fortunate enough to obtain every facility
and encouragement from the Imperial Government. The letter above referred to
was written on the eve of his departure on his journey.

542 Academy of Natural Sciences of Philadelphia.

of those times — the denizens of those caverns — who carried them
there to devour them. In the midst of these testimonials of an
order of things differing from the actual, he had not the slightest
vestige of the existence of man ; and if man had existed, how could
he have escaped the fate of animals stronger than he, who were vic-
tims of these ferocious and gigantic beasts of prey ? This evidence
he thought sufficient to decide the question negatively, when he
unexpectedly met the first remains of the human species under cir-
cumstances which, at least, admit of a contrary solution. He found
these remains in a cavern which contained mixed with them bones
of animals decidedly extinct ; (Platyonyx Bucklandii, Chlamydothe-
rium Humboldtii, Chi. majus, Dasypus sulcatus, Hydrochmrus sulcidens,
&c.) a circumstance which ought to call attention to these interest-
ing relics. Besides, they present all the characters of really fossil
bones. They were in part petrified, and in part penetrated with
iron particles, which gave to them a metallic lustre, resembling
bronze, and at the same time an extraordinary weight. Of the im-
mense age of these remains there can be no doubt ; but, upon the
question of the coexistence with animals whose remains were found
with them, we cannot, unfortunately, arrive at a definite conclusion,
as the cave is situated on the margin of a lake whose waters rise
annually, and in the rainy season enter it ; so it is possible the re-
mains of animals, now existing, might have been more recently in-
troduced, and mixed with those already deposited. These bones
are in different states of preservation ; some differing little from
new bones, while others approximate to the sub-metallic state al-
ready referred to ; but the greater number occupy a grade of decom-
position intermediate between the two extremes.

A similar difference, but less conceivable, he noted among the hu-
man bones, proving a diversity of ages, while all showed an antiquity ;
making them most interesting, even if they do not solve the question
of coexistence. In Europe, (says the Doctor,) the remains of the
great species of terrestrial mammiferous animals are the only proof
of their existence ; as no mention is made of them in history, conse-
quently their extinction dates back more than three thousand years.
Applying the same result to the extinct species of Brazil, with which
they agree in their state, and attributing to the human bones found
in a state perfectly analogous to those which characterize these fos-
sils, we take for them an age of thirty centuries and upward. Ad-
mitting, then, the proofs of these documents, the population of Bra-
zil is derived from very remote times, and undoubtedly anterior to
the time of history.

The question then arises, who were these people ? what their
mode of life ? of what race ? and what their intellectual perfection ?
The answers to these questions are, happily, less difficult and doubt-
ful. He examined various crania, more or less perfect, in order to
determine the place they ought to occupy in the system of anthro-
pology. The narrowness of the forehead, the prominence of the zy-
gomatic bones, the facial angle, the maxillary and orbital conforma-
tion all assign to these crania a place among the characteristics of

Academy of Natural Sciences of Philadelphia. 543

the American race. And it is known, says the Doctor, in continua-
tion, that the race which approximates nearest to this is the Mon-
golian ; and the most distinctive and salient character by which we
distinguish between them, is by the greater depression of the fore-
head of the former. In this point of organization, these ancient
crania show not only the peculiarity of the American race, but this
peculiarity, in many instances, in an excessive degree, even to the
entire disappearance of the forehead. We must allow, then, that
the people who occupied this country in those remote times, were of
the same race as those who inhabited it at the time of the conquest.
We know that the human figures found sculptured in the ancient
monuments of Mexico represent, for the greater part, a singular
conformation of head, — being entirely without forehead, — the cra-
nium retreating backward immediately above the superciliary arch.
This anomaly, which is generally attributed to an artificial disfigu-
ration of the head, or the taste of the artist, now admits a more na-
tural explanation ; it being now proved, by these authentic docu-
ments, that there really existed on this continent a race exhibiting
this anomalous conformation. The skeletons, which were of both
sexes, were of the ordinary height, although two of the men were
above the common stature. These heads, according to the received
opinions in craniology, could not have occupied a high position in
intellectual standing. This opinion is corroborated by finding an
instrument of imperfect construction joined with the skeletons.
This instrument is simply a smooth stone, of about ten inches in
circumference, evidently intended to bruise seeds or hard sub-
stances.

In other caverns he has found other human bones, which show
equally the characteristics of fossils, being deprived of all the gela-
tinous parts, and consequently very brittle and porous in the fracture.
They were, unfortunately, unaccompanied by the bones of any other
animals, so that the principal point of the question remains unde-
cided ; although they go to prove the antiquity and prolonged exist-
ence of the human race on this continent.

The above then, my dear Sir, is a brief synopsis of Dr. Lund's
letter, which may, perhaps, have already reached you by way of
Europe ; but of this I am not assured, and have determined to send
it.

Having given you the general features of this letter, it would be
presumptuous in me to hazard any remarks to one so skilled in
anthropology ; and I would only suggest, that fossil remains are
not confined to Minas Geraes, but are also found in the western
part of this province, and in Bahia.

Near the city of Rio de Janeiro of course nothing of the kind has
been discovered, as the formation is entirely granitic ; but from the
point where the calcareous rocks commence, (about ninety miles in-
land, near Canto Gallo,) I am informed that fossils are abundant.

[ 544 ]
LXXVIII. Intelligence and Miscellaneous Articles.

ENERGIATYPE, A NEW PHOTOGRAPHIC PROCESS.
BY ROBERT HUNT.

V17"HILE pursuing some investigations, with a view to determine
™ ™ the influence of the solar rays upon precipitation, I have been
led to the discovery of a new photographic agent, which can be em-
ployed in the preparation of paper with a facility which no other sen-
sitive process possesses. Being desirous of affording all the informa-
tion I possibly can to those who are anxious to avail themselves of the
advantages offered by photography, I solicit a little space in your
columns for the purpose of publishing the particulars of this new
process. All the photographic processes with which we are at pre-
sent acquainted, sufficiently sensitive for the fixation of the images
of the camera obscura, require the most careful and precise mani-
pulation ; consequently, those who are not accustomed to the nice-
ties of experimental pursuits are frequently annoyed by failures.
The following statement will at once show the exceeding simplicity
of the new discovery.

Good letter-paper is first washed over with the following solu-
tion : —

A saturated solution of succinic acid. ... 2 drachms.

Mucilage of gum-arabic \

Water \\ ...

When the paper is dry, it is washed over once with an argentine
solution, consisting of 1 drachm of nitrate of silver to 1 oz. of
distilled water. The paper is allowed to dry in the dark, and it is
fit for use. It can be preserved in a portfolio, and at any time em-
ployed in the camera. This paper is a pure white, and it retains its
colour, which is a great advantage. At present I find it necessary
to expose this prepared paper in the camera obscura for periods,
varying with the quantity of sunshine, from two to eight minutes,
although, from some results which I have obtained, I am satisfied
that, by a nice adjustment of the proportions of the materials, a
much shorter exposure will suffice. When the paper is removed
from the camera, no trace of a picture is visible. We have then to
mix together 1 drachm of a saturated solution of sulphate of iron
and 2 or 3 drachms of the mucilage of gum-arabic. A wide flat
brush, saturated with this solution, is now swept over the face of
the paper rapidly and evenly. In a few seconds the dormant images
are seen to develope themselves, and with great rapidity a pleasing
negative photographic picture is produced. The iron solution is to
be washed off as soon as the best effect appears, this being done
with a soft sponge and clean water. The drawing is then soaked
for a short time in water, and may be permanently fixed by being
washed over with ammonia, or perhaps better with a solution of the
hyposulphite of soda, care being taken that the salt is afterwards
well washed out of the paper. From the pictures thus produced,
any number of others, correct in position and in light and shadow,
may be produced, by using the same succinated papers in the ordinary
way, from five to ten minutes in sunshine producing the desired effect.

Intelligence and Miscellaneous Articles. 545

The advantages which this process possesses over every other
must be, I think, apparent. The papers are prepared in the most
simple manner, and may be kept ready by the tourist until required
for use. They require no preparation previously to their being
placed in the camera, and they can be preserved until a convenient
opportunity offers for bringing out the picture, which is done in the
most simple manner, with a material which can be anywhere pro-
cured.

Anxious to give the public the advantage of this process during
,the beautiful weather of the present season, I have not waited to
perfect the manipulatory details which are necessary for the produc-
tion of portraits. It is sufficient, however, to say, that experiment
has satisfied me of its applicability for this purpose.

Prismatic examination has proved that the rays effecting this che-
mical change are those which I have elsewhere shown to be perfectly
independent of solar light or heat. I therefore propose to distin-
guish this process by a name which has a general rather than a par-
ticular application. Regarding all photographic phenomena as due
to the principle Energia, I would nevertheless wish to distinguish
this very interesting process as the Energiatype.

I enclose you a few specimens of the results already obtained.
The exceeding sensibility of the Energiatype is best shown by an
attempt to copy engravings or leaves by it. The three specimens I
enclose were produced by an exposure of considerably less than one
second. — Athenceum.

In a subsequent number of the ' Athenaeum,' Mr. Hunt has given
the following additional directions : —

Experience has suggested to me the advantage of adding to the
solution of succinic acid and gum, as previously given, 5 grains of
common salt. This preserves the lights very clear, and indeed im-
proves the sensibility of the paper.

When the solution of the sulphate of iron is laid over the paper,
it is requisite to keep disturbing it, by rapidly but lightly brushing
it up; otherwise numerous little black specks form, which destroy
the photograph. If, as sometimes happens, the surface of the pic-
ture blackens all over, it must not be concluded that the drawing is
destroyed. The whole of this superficial blackness may be removed
by immediately washing with a wet sponge. If the lights become
in any way discoloured, a little exceedingly diluted hydrochloric
(muriatic) acid will restore them to their proper degree of white-
nesss ; but care must be taken that the acid is speedily washed off,
or the shadows will suffer.

When, from the shortness of the exposure, the image developes
itself slowly or imperfectly, a slight degree of warmth brings out
the picture with rapidity and force. Holding the paper a short di-
stance from the fire is the best mode of operating.

METHOD OF PRESERVING ANIMAL SUBSTANCES. BY M. GANNAL.

From the observations made by M. Gannal, and reported to the
Acad£mie des Sciences at a recent sitting, it appears that arsenic

Phil. Mag. S. 3. No. 162. Suppl. Vol. 24. 2 N

54>6 Intelligence and Miscellaneous Articles.

does not permanently preserve animal substances, although it pre-
vents, for the moment, a putrid fermentation.

He alludes to his former communication, explaining how the salts
of alumina act on the gelatine and preserve the animal matter from
putrid fermentation by the combination of the two substances. The
gelatine is thus rendered incapable of putrefaction ; but the other evil,
viz. the destruction by insects, is not avoided. For the latter object
he proposes the following preparation : —

1 kilogramme of sulphate of alum — 1 kilog. = 21 lbs. avoird. ;

100 grammes of nux vomica in powder — 100 grammes = 3-|
oz. av. ;

And 3 litres of water — 3 litres = 5£ imperial pints.

The above to be boiled down to 1\ litres, and then allowed to
cool : the clear liquid is to be drawn off and serves for injection. The
residue is employed in the following manner. With four tablespoons-
ful of this residue mix the yolk of one egg ; let this paste be prepared
as wanted. It is to be used for covering the interior of the skin, and
particularly the fleshy parts which may have been left in skinning
the animal. The yolk of egg serves to preserve the suppleness of
the skin, tanned by the salts of alum.

In order to preserve the feathers of birds he proposes three
modes : —

1 . The employment of nux vomica in powder.

2. An alcoholic tincture of 100 grammes of nux vomica, mace-
rated in 1 litre of alcohol.

3. An alcoholic solution of 2 grammes of strychnine in 1 litre of
alcohol.

Whatever mode may have been used for preserving the animal,
the ravages of insects may be instantly arrested by covering with a
soft brush the whole of the skin, either with the tincture or solution
above described, as may be found best adapted.

If the feathers of birds are of delicate colour, the solution of
strychnine should be employed ; and for those very delicate birds,
where soaking in either of the preparations is not possible, the nux
vomica must be used in powder, taking care to insert it well in the
napes of feathers. In all cases the inside of the skin may be rubbed
with the paste.

In conclusion he states that from his experience he feels assured —

That no arsenical preparation can ensure the preservation of ani-
mal substances ;

That they are destroyed by exposure to the air for a period ex-
ceeding three years ;

That those substances enclosed in hermetically sealed cases are
destroyed even in one year ;

That the soluble salts of alumina are quite effective in arresting
putrid fermentation ; and

That the employment of the preparation of nux vomica, as de-
scribed, perfectly preserves animal substances from the attacks of
insects. — From the Proceedings of the Zool. Soc. Nov. 28th, 1843.

547

INDEX TO VOL. XXIV.

ABSINTHIC acid, composition of, 392.

Academy of Natural Sciences of Phila-
delphia, proceedings of the, 541.

Acids: — ferric,41,498;pyromeconic, 128;
komenic, 134 ; sulphocamphoric, 157 ;
dialuric, 188 ; thionuric, 189 ; allano-
sulphurous, 189 ; alloxanic, 190 ; chlo-
rophenissic, 201 ; chlorindoptic, 202 ;
carbazotic, 203 ; anthranilic, 204 ; car-
bolic, 205 ; chlorazotic, 235 ; gallic,
314; pectic, 319; lithofellinic, 355;
absinthic, 392.

Adams (J. C.) on the elements of the
comet of Faye, 520.

^Ethogen, observations on, 191.

Allen (W.), notice of the late, 524.

Alloxanic acid, preparation of, 190.

Alloxano-sulphurous acid, observations
on, 189.

Alloxantine, preparation of, 186.

Anatase, analysis of, 477.

Andrews (Dr. T.) on the thermal changes
accompanying basic substitutions, 457.

Aniline, observations on, 199.

Animal heat, observations on, 456.

Animal substances, on a method of pre-
serving, 545.

Animals, secretion of carbon by, 468.

Animals and vegetables, on the reciprocal
dependence of, 90.

Apiine, chemical examination of, 155.

Arrott (A. R.) on a class of double sul-
phates, 502.

Austen (R. A. C.) on the geology of the
south-east of Surrey, 65, 222.

Baily's (F.) Catalogues of Stars, notice re-
specting, 538.

Balmain (W. H.) on aethogen, 191.

Barry (Dr. M.) on Bischoff's history of
the development of the ovum of the
rabbit, 42, 281.

Bath-waters, analysis of the, 371.

Baudrimont (M.) on chlorazotic acid,
235.

Bayonne, on the geology of the neigh-
bourhood of, 55.

Beaumontite, analysis of, 236.

Beche (Sir II. T. de la) on estuaries and
their tides, 485.

Belemnites, description of some, 464.

Berzelius (M.), notice respecting, 396.

Bidard (M.) on guano, 317.

Binney (E. W.) on some remarkable fos-
sil trees discovered near St. Helen's,
165.

Bischoff (Prof.) on the development of
the ovum, 42, 281.

Bones, analysis of ancient and fossil, 154.

Boole (G.) on a new method of analysis,
459.

Bowring (J. C.) on the amalgamation of
silver ores in Mexico, 467.

Braconnot (M.) on apiine, 155.

Brewster (Sir D.) on the law of visible
position in single and binocular vision,
356, 439.

Bridges (Mr.) on the habits of some of
the smaller species of Rodents, 541.

Bronwin (Rev. B.) on differential equa-
tions of the moon's motion, 85 ; on
some definite integrals, 491.

Brown (J.) on some pleistocene deposits
near Copford, Essex, 62.

Buckland (Dr.) on Ichthyopodolites, 230.

Buckman (J.) on the occurrence of the
remains of insects in the upper lias,
377.

Cacciatore (Prof. N.), notice of the late,
525.

Calculi, on some new species of, 354.

Calotype process, observations on the
practice of the, 322.

Carbazotic acid, 203.

Carbonic oxide, on an easy method of
preparing, 24.

Cartwright (D. E.), A Memoir of the life,
writings and mechanical inventions of,
reviewed, 299.

Carty (J.) on a new cyanide of gold, 515.

Catechuic acid, observations on, 500.

Ceraine, composition of, 19.

Challis (Prof.) on the application of cri-
teria of integrability, 94.

Chemistry : — on the production of chlo-
rophylle by yellow light, 1 ; action of
alkalies on wax, 17 ; action of oil of
vitriol on ferrocyanide of potassium,
21 ; ferric acid, 41, 498; preparation of
hyposulphite of soda, 78; action of
chlorides on protochloride of mercury,
t*.; chemical constitution of flax and
hemp, 98 ; examination of the Tagua
2N2

548

INDEX.

nut, 104 ; investigation of the organic
bases in coal-gas naphtha, 115, 193,
261 ; products of distillation of meco-
nic acid, 128 ; detonation of the alloy
of potassium and antimony, 153 ; ana-
lysis of fossil hones, 154 ; apiine, 155 ;
sulphocamphoric acid, 157 ; on the
voltaic decomposition of solutions, 161 ;
on the products of decomposition of
uric acid, 186 ; on aethogen, 191 ; clas-
sification of granitic rocks, 220 ; on
the equivalent of zinc, 233 ; distinction
of zinc from manganese, 234 ; prot-
iodide of iron, ib. ; chlorazotic acid,
235 ; on the manner in which cotton
unites with colouring substances, 241 ;
experiments on coffee, 313 ; prepara-
tion of gallic acid, 314 ; analysis of
guano, 317, 394, 470; pectic acid,
319 ; on the elasticity of gases, 354 ;
on biliary concretions, ib.; solubility
of metals in persalts of iron, 365 ; ana-
lyses of the Bath and Bristol waters,
371 ; on fermentation, 372 ; absinthic
acid, 392 ; preparation of osmium, 393 ;
on heat disengaged in combinations,
401, 457 ; on animal heat, 456; on the
electrolysis of secondary compounds,
463 ; on ozone, 467 ; existence of phos-
phoric acid in rocks of igneous origin,
467 ; on the amalgamation of silver
ores in Mexico, ib. ; secretion of car-
bon by animals, 468 ; preparation of
iridium, 474 ; double carbonate of am-
monia and magnesia, 475.

Chevallier (Rev. Prof.) on an astronomi-
cal time watch-case, 517.

Chimaera, new species of fossil, 51, 376.

Chloranil, observations on, 200.

Chlorazotic acid, 235.

Chlorides, action of, on protochloride of
mercury, 78.

Chlorindatmite, observations on, 201.

Chlorindoptic acid, 202.

Chlorophylle, production of, by yellow
light, 1 ; destruction of, by light, 13.

Chromo-cyanotype, 435.

Clarke (Rev. W. B.) on a fossil pine
forest on the eastern coast of Austra-
lia, 59.

C. M. on the experiments of Moser, 38.

Coffee, experiments on, 313.

Colouring matter, on the manner in which
cotton unites with, 241.

Comet, observations respecting the great,
300.

Comet of Faye, on the orhit of, 5 1 9.

Conic sections, observations on, 49.

Connell (A.) on the Tagua nut, or vege-
table ivory, 104 ; on the voltaic de-
composition of solutions, 161.

Coombe (Rev. J. A.) on the force of equi-
librium of an inextensible string, 423.

Cooper (J. T.) on catechuic acid, 500.

Cornwall and South Devon, on the geo-
logy of, 332.

Crinoidea, on the locomotive and non-
locomotive powers of the, 57.

Crum (W.) on the manner in which cot-
ton unites with colouring matter, 241.

Crystals, on a means of preserving, for the
microscope, 505.

Cundell (G. S.) on the practice of the
calotype process of photography, 322.

Cunningham (J. J.) on coffee, 313.

Cyanide of gold, on a new, 515.

Cyanol, preparation and chemical consti-
tution of, 121 ; on the combinations
of, 193 ; products of the decomposition
of, 199.

Damour (A.) on melilite, 314 ; on llum-
boldtilite, 316 ; on the identity of sco-
rodite and neoctese, 476 ; on anatase
and rutile, 477.

Daniell (Prof.) on the electrolysis of se-
condary compounds, 463.

Davy (Dr. J.) on animal heat, 456.

Dawes (Rev. W. R.) on the divisions of
the exterior ring of the planet Saturn,
306.

Definite integrals, on some, 491.

Delesse (A.) on Beaumontite, 236 ; on
Sismondine, 238.

Descartes, demonstration of the rule of,
24.

Dialurate of ammonia, observations on,
187.

Dial uric acid, on the preparation of, 188.

Differential and integral calculus, on the
notations employed in, 25.

Dinomis, account of the, 378.

Distances, on the determination of, 181.

Drach (S. M.) on the enumeration of prime
numbers, 192.

Earth, on changes in the temperature of
the, 144.

Egerton (Sir P. G.) on some new species
of fossil fishes, 51, 375.

Electric conduction, speculations concern-
ing, 136.

Electric fluids, on the cause of dissimila-
rity in the phenomena of, 174.

Electrolysis, on the intermittent character
of the voltaic current in certain cases
of, 106.

Electrolysis of secondary compounds, on
the, 463.

Encrinite, new species of, 58.

Energiatype, 544.

Entozoonfolliculorum, description of the,
455.

Estuaries, observations on, 485.

INDEX.

549

Eudionietry, on the application of the gas
voltaic battery to, 268, 346, 422.

Eye, on the adjusting power of the, 474.

Faraday (Prof. M.) on the nature of mat-
ter, 136.

Favre (P. A.) on the equivalent of zinc,
233 ; on a double carbonate of ammo-
nia and magnesia, 475.

Faye's comet, on the orbit of, 519.

Fermentation, observations on, 372.

Ferric acid, on the composhion of, 41,
498.

Ferrocyanide of potassium, action of oil
of vitriol upon, 21.

Fish, descriptions of new fossil, 51, 375.

Fitton (Dr. W. II.) on the lower green-
sand of the Isle of Wight, 224 ; on the
lower greensand of Kent, 311.

Flax and hemp, on the chemical consti-
tution of, 98.

Fossil chimaeroid fishes, new species of,51.

Fossil trees, observations on some, 74,
165.

Fownes (G.) on the action of oil of vitriol
upon ferrocyanide of potassium, 21.

Francis (W.) on the action of alkalies on
wax, 17 ; on African guano, 470.

Fremy (E.) on the preparation of osmium,
393 ; on the preparation of iridium,
474.

Fromberg (M.) on pectic acid, 319.

Furze (J. N.) on fermentation, 372.

Galbraith (W.) on the determination of
distances, 181.

Gallic acid, new process for preparing, 314.

Gannal (M.) on a new method of pre-
serving animal substances, 545.

Gardner (Dr.) on the action of yellow
light and indigo light on plants, 1.

Gases, remarks on the elasticity of, 354.

Gassiot (J. P.) on an extensive series of
the water battery, 460.

Gas voltaic battery, application of, to eu-
diometry, 268, 346, 422.
Geological Society, proceedings of the,

51, 144, 217,308, 375.
Geology : — descriptions of some new fos-
sil fish, 51, 375 ; geology of Bayonne,
55 ; observations on the Crinoidea, 57 ;
new Encrinite, 58 ; on a fossil pine-
forest at Kurrur-kurran, 59 ; on some
pleistocene deposits in Essex, 62 ; on
the tin-mines of the Tenasserim pro-
vince, 63 ; geology of Surrey, 65, 222 ;
on the freshwater fossils of Brora, 71 ;
on some fossil trees found in Nova
Scotia, 74 ; on the theory of reciprocal
dependence in the animal and vegetable
creations as regards its bearing on pa-
laeontology, 90 ; on changes in the tem-
perature of the earth, 144 ; on the coal-

formation of Nova Scotia, 146 ; on some
fossil trees discovered near St. Helen's,
165 ; on the heaves of metalliferous
veins, 180, 258 ; geology of the west
coast of Africa, 217; classification of
granitic rocks, 220 ; on the lower green-
sand of the Isle of Wight, 224, 311 5
on scratched rocks, 230; on Ichthy-
opodolites, ib. ; on some fossiliferous
beds of Southern India, 231 ; on the
Killas group of Cornwall and South
Devon, 232 ; geology of North Wales,
246 ; on the geology of the vicinity of
Hythe, 308 ; on remains of insects in
the upper lias of Gloucester, 377 ; on
the Dinornis, 378 ; description of Be-
lemnites from the Oxford clay, 464 ; on
some fossil remains from Brazil, 541.
Gesner (Dr. A.) on the geology of Nova

Scotia, 149.
Girardin (M.) on the composition of an-
cient and fossil bones, 154 ; on guano,
317.
Gold, on a new cyanide of, 515.
Goldschmidt's (Dr.) calculation of the

elements of the new comet, 519.
Goodman (J.) on the cause of dissimila-
rity in the phenomena of electric fluids,
174.
Graham (Prof. T.) on the heat disengaged

in combinations, 401.
Granitic rocks, on the classification of,

220.
Gregory (Prof.) on some products of the

decomposition of uric acid, 186.
Grove (Prof.) on the correlation of phy-
sical forces, 76 ; on the gas voltaic bat-
tery, 268, 346, 422.
Guano, analyses of, 317, 394, 470.
Harkness (Mr.) on changes in the tem-
perature of the earth, 144.
Heat, animal, observations on, 456.
Heat disengaged in combinations, expe-
riments on the, 401, 457.
Hemp, on the chemical constitution of,

98.
Henderson (Prof.) on the orbit of the

comet of Faye, 519.
Hennessy (H.) on a meteorological phe-
nomenon, 238.
Henwood (W. J.) on the heaves of me-
talliferous veins by cross veins, 180,
258.
Herapath's (W.) analysis of the Bath wa-
ters and of the Bristol hot-well water,
371.
Herschel (Sir J. F. W.) on the entrance
passages in the pyramids of Gizeh, 481 ;
on the increase in magnitude of the
star r] Cygni, 523.
Hofmann (Dr. A. W.) on the organic bases

550

INDEX.

contained in coal-gas naphtha, 115, 193,
261.

Humholdtilite, analysis of, 316.

Hunt (R.) on the influence of light on
plants, 96 ; on chromo-cyanotype, 435,
455 ; on energiatype, a new photogra-
phic process, 544.

Hyposulphite of soda, preparation of, 78.

Ichthyopodolites, observations on, 230.

Insects, on the occurrence of the remains
of, in the upper lias, 377.

Integrability, on the application of crite-
ria of, 94.

Interference, on the undulatory theory
of, 81.

Iridium, preparation of, 474.

Iron, protiodide of, on the preparation of
the, 234.

J. J. on the notations employed in the
differential and integral calculus, 25.

Joule (J. P.) on the intermittent charac-
ter of the voltaic current in certain
cases of electrolysis, and on the inten-
sities of voltaic arrangements, 106.

Kane (Dr. R.) on the chemical constitu-
tion of flax and hemp, 98.

Kaye (C. T.) on some fossiliferous beds
of Southern India, 231.

Kent (E. N.) on a new process for pre-
paring gallic acid, 314.

Komenate of iron, preparation and com-
position of, 134.

Latham (Dr. J.), notice of the late,
214.

Latham (Prof.) on the science of pho-
netics, 279, 420.

Leucol, chemical investigation of, 261.

Light, action of yellow, in producing the
green colour of plants, 1 ; influence of,
on plants, 96.

, latent, observations on, 232.

Lithofellinic acid, observations on, 354.

London Institution, proceedings of the,
76.

Low's Simple Bodies of Chemistry, re-
viewed, 296.

Lund's (Dr.) researches in Brazil, account
of, 541.

Lyell (C.) on upright fossil trees found in
the coal-strata of Cumberland, Nova
Scotia, 74 ; on the coal-formation of
Nova Scotia, 146.

MacCullagh (Prof.) on the laws of metal-
lic reflexion, and on the mode of making
experiments upon elliptical polariza-
tion, 380.

Macintosh (C), notice of the late, 214.

Magnetism, terrestrial, contributions to,
466.

Man, on the coexistence of, with extinct
mammiferous animals, 541.

Manganese, mode of distinguishing zinc

from, 234.
Marguerite (M.) on the chemical consti-
tution of wolfram, 153.
Matter, on the nature of, 136.
Meconic acid, on the products of the di-
stillation of, 128.
Melilite, analysis of, 314.
Mercury, on the latent light of, 232.
Metalliferous veins, on the displacements

of, 180, 258.
Metals, on the solubility of, in persulphate

and perchloride of iron, 365.
Meteorological observations, 79, 159, 239,

319, 399, 479.
Meteorological phenomenon, account of a,

238.
Mialhe (M.) on the action of chlorides

on the protochloride of mercury, 78 ;

on the preparation of the protiodide of

iron, 234.
Mineralogy: — constitution of wolfram,

153; analysis of Beaumontite, 237;

of Sismondine, 238 ; of melilite, 314 ;

of Humholdtilite, 316 ; identity of sco-

rodite and neoctese, 476; comparative

analysis of anatase and rutile, 477.
Moon (R.) on the undulatory theory of

interference, 81.
Moon's motion, differential equations of

the, 85.
Morgan (A. de) on the reduction of a

continued fraction to a series, 15.
Moser (Prof.), notes on the experiments

of, 38 ; on the latent light of mercury,

232.
Murchison (R. I.) on the freshwater beds

of Brora, 72.
Myricine, composition of, 19.
Naphtha from coal-gas, chemical investi-
gation of the bases contained in, 115,

193,261.
Napier (J.) on the solubility of metals in

persulphate and perchloride of iron,

365.
National Institute of the United states,

proceedings of the, 468.
Neocomian system of foreign geologists,

observations on the, 72.
Neoctese, on the identity of, with Scoro-

dite, 476.
Newbold (Lieut.) on the temperature of

the springs, wells and rivers of India

and Egypt, 461.
Osmium, process for obtaining, 393.
Otto (M.) on distinguishing zinc from

manganese, 234.
Ovum, observations on the history of the

development of the, 42, 281.
Owen (Prof.) on the remains of the Di-

nornis, 378 ; on some Belemnites, 464.

INDEX.

551

Ozone, notice respecting, 466.

Pascal and Brianchon's theorems on conic
sections, remarks on, 49.

Pearce (J. C.) on the locomotive and
non-locomotive powers of the Crinoi-
dea, 57 ; on a new species of Encri-
nite, 58.

Pectic acid, analysis of, 319:

Phillips (R.) on the elasticity of gases,
354; on the adjusting power of the
eye, 474.

Phonetics, observations relative to the
science of, 279, 420.

Phosphoric acid, existence of, in rocks of
igneous origin, 467.

Photographic processes, account of some
new, 435, 544.

Photography, on the practice of the calo-
type process of, 322.

Plants, action of yellow light in pro-
ducing the green colour, and indigo
light the movements of, 1 ; on the in-
fluence of light on, 96 ; on the ascent
of the sap in, 461.

Polarization, elliptic, on the mode of
making experiments upon, 380.

Potassium and antimony, detonation of
the alloy of, 153.

Pratt (S. P.) on the geology of the neigh-
bourhood of Bayonne, 55.

Preisser and Girardin (MM.) on the com-
position of ancient and fossil bones,
154.

Prime numbers, on the empirical law in
the enumeration of, 192.

Pseudo-ceraine, composition of, 20.

Pyramids of Gizeh, on the entrance pass-
ages in the, 481.

Pyromeconic acid, on the properties and
constitution of, 128.

Rabbit, development of the ovum of the,
42.

Rainey (G.) on the ascent of the sap in
plants, 461.

Reflexion, metallic, on the laws of, 380.

Rigg (R.) on the secretion of carbon by
animals, 468.

Robertson (A.) on the freshwater fossils
of Brora, 71.

Rocks, on the scratched surfaces of, 230.

Royal Astronomical Society, proceedings
of the, 300, 516.

Roval Irish Academy, proceedings of the,
380.

Royal Society, proceedings of the, 206,
455 ; Address of the President, 207.

Royle (Prof.) on the tin-mines of the
Tenasserim province, 63.

Rutile, analysis of, 477.

Sabine's (Col.) contributions to terrestrial
magnetism, 466.

Salmon (G.) on the properties of surfaces
of the second degree, 49.

Saturn, on the divisions of the exterior
ring of the planet, 306.

Schcenbein (Prof.) on ozone, 466.

Scorodite, on the identity of, with neoc-
tese, 476.

Sedgwick (Rev. A.) on the geological
structure of North Wales, 246.

Silver, on a curious change in the mole-
cular structure of, 503.

Silver ores, on the amalgamation of, in
Mexico, 467.

Simms (F. W.) on the geology of the vici-
nity of Hythe, 308.

Simple Bodies of Chemistry, Inquiry into
the Nature of the, reviewed, 296.

Sismondine, description and analysis of,
238.

Smith (J. D.) on ferric acid, 41, 498.

Smyth (C. P.) on the apparent magni-
tude of the fixed stars, 516 ; on the
advantages of employing large specula
for astronomical observations, 518.

Specula, on the advantages of employing
large,for astronomical observations,5 1 8.

Spencer (H.) on the reciprocal depend-
ence of animals and vegetables as re-
gards its bearing on palaeontology, 90.

Stanger (Dr. W.) on the geology of the
west coast of Africa, 217.

Stars, on the apparent magnitude of the
fixed, 516.

Stenhouse (J.) on the products of distil-
lation of meconic acid, 128.

Sulphates, on a class of double, 502.

Sulphocamphoric acid, observations on,
157.

Sylvester (J. J.) on the analysis of com-
binatorial aggregation, 285.

Tagua nut, chemical examination of the,
104.

Taylor (T.) on some new species of biliary
and intestinal concretions, 354.

Teas, observations on the green, of com-
merce, 507.

Tebay (S.) on the demonstration of the
rule of Descartes, 24.

Teschemacher (E. F.) on African guano,
394.

Thionurate of ammonia, observations on,
189.

Tides, observations on, 485.

Tin-mines of the Tenasserim province,
observations on the, 63.

Trevelyan (W. C.) on scratched surfaces
of rocks, 230.

Uric acid, on some products of the de-
composition of, 186.

Vegetable ivory, chemical examination
of, 104.

552

INDEX.

Vegetables and animals, on the reciprocal
dependence of, 90.

Vision, single and binocular, on the law
of visible position in, 356, 439.

Voltaic arrangements, on the intensities
of various, 106.

Voltaic circuit, on the electrical and che-
mical action which takes place before
and after the completion of the, 460.

Voltaic decomposition of solutions, ob-
servations on the, 161.

Vyse (Col. H.) on the entrance passages
in the pyramids of Gizeh, 481.

Walchner (M.) on the preparation of hy-
posulphite of soda, 78.

Wales, on the geological structure of,
246.

Wallace (Prof.), notice of the late, 527.

Wallace (R.) on the classification of gra-
nitic rocks, 220.

Walter (M.) on sulphocamphoric acid,
157.

Warington (R.) on the action of alkalies

on wax, 17; on a curious change in

the molecular structure of silver, 503 ;

on the preservation of crystals of salts

for the microscope, 505 ; on the green

teas of commerce, 507.
Wax, action of alkalies on, 17.
Williams (Rev. D.) on the Killas group

of Cornwall and South Devon, 332.
Wilmot (Capt. F. E.) on a remarkable

luminous spot in the sea, 206.
Wilson (E.) on Enlozoon folliculorum,

455.
Wolfram, on the chemical constitution of,

153.
Zinc, on the equivalent of, 233 ; mode of

distinguishing from manganese, 234.
Zoological Society, proceedings of the,

378.
Zwenger (C.) on absinthic acid, 392.

END OF THE TWENTY-FOURTH VOLUME.

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