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THE
LONDON and EDINBURGH

PHILOSOPHICAL MAGAZINE

AND

JOURNAL OF SCIENCE.

CONDUCTED BY

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

AND

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

" Nee aranearum sane textus idee- melior quia ex se fila gignunt, nee noster
vilior quia ex alienis libamus ut apes." Just. Lips. Monit. Polit. lib. i. cap. 1.

VOL. V.

NEW AND UNITED SERIES OF THE PHILOSOPHICAL MAGAZINE
AND JOURNAL OF SCIENCE.

JULY— DECEMBER, 1834,

LONDON:

PRINTED BY RICHARD TAYLOR, RED LION COURT, FLEET STREET,
Printer to the University of London.

SOLD BY LONGMAN, REES, ORME, BROWN, GREEN, AND LONGMAN; CADELL;
BALDWIN AND CRADOCK; SHERWOOD, GILBERT, AND PIPER; SIMPKIN

• AND MARSHALL; AND S. HIGHLEY, LONDON: BY ADAM

BLACK, EDINBURGH; SMITH AND SON, GLASGOW;

HODGES AND M'ARTHUR, DUBLIN;

AND G. G. BENNIS, PARIS.

TABLE OF CONTENTS.

NUMBER XXV— JULY. Page

Mr. R. W. Fox on Magnetic Attraction and Repulsion and on

Electrical Action 1

Mr. G. Fairholme on the Falls of Niagara, with some Observa-
tions on the distinct Evidence which they bear to the Geo-
logical Character of the North- American Plains 11

Rev. John Kenrick on the alleged Greek Traditions of theDeh

luge, {concluded) 25

Dr. W. C. Henry's Remarks on the Atomic Constitution of

Elastic Fluids 33

Mr. J. H. Pratt's Demonstration of the Parallelogram of Forces. 39

Mr. A. Connel's Analysis of Levyne, 40

Rev. W. D. Conybeare on the probable future Extension of

the Coal-fields at present worked in England {concluded) . . 44
Mr. J. Hogg on the Influence of the Climate of Naples upon
the Periods of Vegetation as compared with that of some

other Places in Europe {continued) 46

Mr. J. Blackwall's Characters of some undescribed Species of

Araneidce 50

Proceedings of the Geological Society 53

Linnsean Society 70

Zoological Society 72

Royal Institution of Great Britain 74

New Books : — Prof. Daubeny's Inaugural Lecture on the Study

of Botany 75

Recent Discovery of Bones of the Iguanodon 77

Muriatic Acid in Fluor Spars — Polyspherite, or Brown Phos-
phate of Lead — New Radical Analogous to Cyanogen 78

M. Boussingault on Suboxide of Lead and Protoxide or Tin —

Scientific Books 79

Meteorological Observations made by Mr. Thompson at the
Garden of the Horticultural Society at Chiswick, near
London, and by Mr. Veall at Boston 80

NUMBER XXVI.— AUGUST.

Capt. P. Yorke's Experiments and Observations on the Action
of Water and Air on Lead 81

Rev. H. Moseley on the Application of the Principle of Least

Pressure to the Theory of Resistances 95

a2

IV CONTENTS.

Page
Mr. G. Rose on the crystallized Compounds of Osmium and

Iridium found in the Ural 101

M. Nils Nordenskiold on Phenakite, a new Mineral from the

Ural 102

Mr. J. Hogg on the Influence of the Climate of Naples upon
the Periods of Veg'etation as compared with that of some

other Places in Europe (concluded) 102

Mr. VV. West on a remarkable Analogy between ponderable

Bodies, and Caloric and Electricity 110

Rev. P. Keith on the Internal Structure of Plants 112

Mr. W. Hopkins's Remarks on Farey's Account of the Strati-
fication of the Limestone District of Derbyshire 121

Dr. Prout's Reply to Dr. W. C. Henry. . . „ 132

Prof. J. D. Forbes's Account of some Experiments on the
Electricity of Tourmaline, and other Minerals, when ex-
posed to Heat 1 33

Proceedings of the Zoological Society 143

M Dcebereiner on some new Combinations of Platina 150

M. C. Matteucci on the Rotary Motion of Camphor 152

On Margaron, Stearon, and Oleon 153

M. Boussingault's supposed Compound of Hydrogen and Pla-
tina 1 55

M. Wohler on Borates of Magnesia 156

M. Payen on the Action of Tannin and some other Substances

on the Roots of Plants 157

Discovery of Platina in France — Prof. Haussmann on Mr.

Whewell's Account of his Minerological Works 158

Mr. J. H. Pratt's Improvement in Professor Henslow's Clino-
meter— Primary Geology 159

Meteorological Observations 160

NUMBER XXVII.— SEPTEMBER.

Mr. Faraday's Experimental Researches in Electricity. — Se-
venth Series 161

Rev. P. Keith on the Internal Structure of Plants (continued) 181

Mr. W. G. Horner's Considerations relative to an interesting
Case in Equations, connected with the Investigation of the
" Principle of Least Pressure " 188

Mrs. Griffiths's Observations on the Spectra of the Eye and the
Seat of Vision 192

Mr. J. Bryce's Addendum to a Descriptive Catalogue of the
Minerals of the North of Ireland 196

Prof. Young on the Development of certain Trigonometrical
Functions 198

W. H. M.'s Description of an Improvement in the Construc-
tion of Say's Instrument for measuring Specific Gravities . . 203

Rev. P. Keith on Phytological Errors and Admonitions 205

CONTENTS. V

Page

Proceedings of the Geological Society 211

Zoological Society 230

Entomological Society 236

Mr. Breithaupt's Mineralogy — Observations on the Tempera-
ture of Artesian Wells in Degrees of the Centigrade Ther-

meter, the Depths being expressed in Metres 237

M. Jacobson on the Physical and Therapeutic Properties of
Chromate of Potash — M. Berzelius's Discovery of Chrenic
and Apochrenic Acids in the Mineral Waters of Porta .... 238

Scientific Books 239

Meteorological Observations 240

NUMBER XXVIII.— OCTOBER.

Mr. C. Blackburn on a Method of determining the Number of

Signals which can be made by the Modern Telegraphs .... 241
Mr. W. G. Carter's Remarks on Mr. Beke's Papers on the

Gopher -wood, and the former Extension of the Persian Gulf. 244
Mr. Faraday's Experimental Researches in Electricity. — Se-
venth Series {continued) 252

Mr. J. Nixon on the Tides in the Bay of Morecambe 264

Mr. J. Barton on the Influence of high and low Prices on the

Rate of Mortality 278

On the Reappearance of Halley's Comet. 284

Rev. P. Keith on the Internal Structure of Plants [concluded) 284

Proceedings of the Geological Society 292

Linnsean Society 298

Royal Astronomical Society 301

Zoological Society 311

M. Persoz on the Preparation of Osmium and Iridium 314

M. Gay-Lussac on the Purification of Carbonate of Soda —

M. Magnus on the Fossil Wax of Moldavia 316

Mr. Sturgeon's Caution to Experimenters with the Electrical

Kite 317

Mr. W. Thompson on some remarkable Crystals of Snow. ... 318

Obituary : Professor Harding 319

Meteorological Observations ; 320

NUMBER XXIX.— NOVEMBER.

Mr. H.F. Talbot's Experiments on Light 321

Mr. Faraday's Experimental Researches in Electricity. — Se-
venth Series {continued.) 334

VI CONTENTS.

Page

Account of the new Observatory for Magnetic Observations at

Gottingen 344

Mr. Faraday on the Magneto-electric Spark and Shock, and
on a peculiar Condition of Electric and Magneto-electric

Induction 349

Mr. J. Thomson on the Mummy Cloth of Egypt ; with Obser-
vations on some Manufactures of the Ancients 355

Mr. C. Blackburn on a Method of determining the Number of

Signals which can be made by the Modern Telegraphs .... 365
Dr. L. Agassiz's Observations on the Growth and on the bila-
teral Symmetry of Echinodermata 369

Mr. R. Addams's Account of a peculiar Optical Phenomenon

seen after having looked at a moving Body, &c 373

K.'s Account of some curious Facts respecting Vision 375

Mr. Sturgeon's Account of some Magneto-electrical Experi-
ments made with the large Magnet at the Exhibition Room,

at Adelaide-street 376

Prof. R. Hare's Apparatus for Freezing Water by the Aid of

Sulphuric Acid 377

Proceedings of the Zoological Society 379

British Association for the Advancement

of Science , 386

Oxide of Carbon free from Carbonic Acid 391

Analysis of the Brain 392

Valerianic Acid and its Salts 396

Hydrocyanic iEther — Distillation of Tartaric and Pyrotartaric

Acids , 397

Mr. G. O. Rees on the Existence of Titanium in Organic

Matter 398

Crystallization of Kalium or Potassium — Scientific Books. . . . 399
Meteorological Observations 400

NUMBER XXX.— DECEMBER.

Prof. Graham on Phosphuretted Hydrogen 401

Mr. D. Lyon's Observations on Magnetic Substances 415

Mr. W. Sturgeon's Description of a Thunder-Storm as ob-
served at Woolwich; with some Observations relative to the
Cause of the Deflection of Electric Clouds by high Lands;
and an Account of the Phenomena exhibited by means of

a Kite elevated during the Storm 418

Mr. Faraday's Experimental Researches in Electricity. — Se-
venth Series (concluded) 424

Mr. J. H. Wheeler's Experiments and Observations on the Ap-
plication of Photometry to certain Cases connected with the
Undulatory Theory of Light 439

CONTENTS. Vll

Page
Mr. Faraday's Additional Observations respecting the Mag-
neto-electric Spark and Shock 444

Mr. A. T.Wood on the Action of Oxalic Acid upon Chloride

of Sodium 445

Prof. J. Phillips on Subterranean Temperature, as observed
at a Depth of Five Hundred Yards below the Level of the

Sea, in Latitude 54° 55' North, November 15, 1834 446

Proceedings of the Royal Society 451

Geological Society 459

New Books: — The Transactions of the Entomological Society

of London, Vol. 1. Part I 462

Discovery of Saurian Bones in the Magnesian Conglomerate
near Bristol — Experiments on the active Principle of Sarsa-

parilla, by M. Poggiale 463

Preparation of Cyanuret of Potassium — Composition of Lithic

Acid 465

Geological Survey of the United States 466

Meteorological Observations 468

Index 469

PLATES.

I. A Plate illustrative of Professor Faraday's Experimental Researches
in Electricity.
II. An Engraving from a Drawing by Bauer, illustrative of Mr. Thomson's
Paper on the Mummy Cloth of Egypt.

ERRATA.

Page 91, line 1 7, dele By continued effusions of distilled water.

92, — 21-22, after lime insert water: after boiled, insert a full stop.

92, — 28, after mentioned insert (4. and 5.)

93, — 27, after water insert it was as copper ;

94, — 27, dele (28.)

95, — 14, for (32.) read (38.)

191, — 6, for s — , read s -j-, and for a. read a.

191, — 13, for y2— , read 3/2+.

THE

LONDON and EDINBURGH

PHILOSOPHICAL MAGAZINE

AND

JOURNAL OF SCIENCE,

[THIRD SERIES.]

JULY 1834..

I. On Magnetic Attraction and Repulsion and on Electrical
Action. By Robert Were Fox*.

HAVING observed, whilst I was using my dipping-needle
with its magnetic deflector (noticed in No. 20, Third
Series of the London and Edinburgh Philosophical Magazine :
vol. iv. p. 81), that the ratio of the magnetic forces was not
uniform, I was induced to enter upon a series of experiments
for the purpose of investigating these forces.

Of the various methods I adopted, I think it may be suffi-
cient for me to describe that only which seemed on the whole
to be most satisfactory and decisive.

To the extremity of a horizontal beam, delicately balanced
on knife-edges, a magnetic bar was attached, with its axis in a
vertical direction, and a counterpoise was suspended from the
other end of the beam. Immediately under the attached or
suspended magnet, and in the same vertical line, another si-
milar magnet was placed, in a glass tube, in which it could be
moved freely up or down, a graduated scale having been
fixed to the tube to mark the exact distance between the con-
tiguous poles of the two magnets ; and when the poles were
brought very near each other, mica, paper, card-board, &c,
were placed between them, 2, 4, or 8 pieces being pasted to-
gether to obtain the duplicate ratios of the distances. Minute
weights were suspended to ascertain the force of attraction or

* Communicated by the Author, on the 9th of April last.
Third Series. Vol. 5. No. 25. July 1834. B

2 It. W. Fox on Magnetic Attraction and Repulsion,

repulsion, as the case might be; and a small pin was fixed
immediately above the suspended magnet, in order to insure
the uniformity of its position, the weights being regulated
accordingly.

I first attached to the beam a small cylindrical magnet l-£
inch long and jth of an inch in diameter, the south end being
downwards; a similar magnet was placed in the tube with
its north end upwards ; when the ratio of their attractive forces
at different distances appeared to be as follows :

Weight in Tenths
of a Grain.
1-0
3-5
.. Y6-

Distance.
1+ inch

•I- —
+ —

42-5

Distance,

Weight in Tenths
of a Grain.
,V inch . . 101-
j£ — .. 204-
& f- .'. 411-

1* — .. 821"

The same suspended magnet attracting a cylinder of soft
iron, of the same dimensions, substituted for the magnet in the
glass tube:

Distance.

Weight in Tenths
of a Grain.

Distance. Weight in Tenths
of a Gram.

■$- inch

•5

yT inch . . 46-

4- —

1-8

,V — .. 96-

* —

7'

Vr — •• 197'

tV —

.. 22-

The arrangement the same as the foregoing, except that
the north pole of the second magnet was in contact with the
lower end of the soft iron in the tube :

Distance.
i- inch

* —

Weight in Tenths

Distance.

Weight in Tenths

of a Grain.

of' a Grain.

1-0

-jV inch

94-

4*

"TV

.. 195-

. 12-5

■sV ~"~

. . 386-

.. 42-

I afterwards substituted for the magnets above described
two others, each 3 inches long and T^th of an inch in diame-
ter, when the following results were obtained :

The suspended magnet with its north end downwards :

Attracting.

istance.

Weight in
ofaG

Tenths
rain.

Distance.

Weight in Tenths
of a Grain.

1 inch

20

Vt inch .

211*0

7'5

tV — •

432-

■k —

19-5

T-W — ""

810-

i —

48-

-5-f-B-

1590*

rV —

.. 99-

in contact

12000-

R. W. Fox on Magnetic Attraction and Repulsion, S

Repelling?

Distance.
1 inch

* —

4 —

■the poles of the lower magnet being reversed:

— ! ' Weight in Tenths

Distance. <;faGrajn.

Vv »nch -

Weight in Tenths

of a Grain.
. . 2-5

. 75

. 14 5
. . 25'
,. 29-

The arrangement the same as before, but the force of the

lower magnet diminished

Attracting.

Weight in Tenths
of a Grain.

Distance.

inch . . 2-0

— .. 8-

— . . 20-5

— . . 42 5

— . . 85-

— .. 175-

-r.hr — .. 390-

t^t — .. SOS-
Tissue [japer interposedl 140*
1 thin plate of mica . . 2400*

Repelling,

T
i

tv . Weight in Tenths

Distance. ? rf— :u

ot a (jrram.

2 thin plates of mica 1320.

4 Ditto do. 720-

An exceedingly tiling

tilm of mica which >9,660*
polarised light . . J

Ditto do. doubled 5,020-

Surfaces of mag-1 iqqqq.
nets in contact J '

Edges only in contact 13,60')*

Distance.

Weight
of a

in Tenths
Grain.

Became attractive

Weight.

£ inch

# g

20

at V-r inch

10-

i

. .

4'

ttV ~

39-

+ —

5-

ttT —

77-

tV "~ "

••

2-

in contact

143-
. 1223-

The above results, which are only a small portion of those
I have obtained, may be regarded as tolerably near approxi-
mations to the truth under the circumstances of the case,
and are, I think, sufficient to show that the laws of magnetic
attraction and repulsion alter according to the distance of the
magnets from each other, the force at small distances being
in the simple inverse ratio of the distance, and when further
separated, in the inverse ratio of the square of the distance..
This change of ratio in the case of attraction, gradually took
place at the distance of from £th to jth of an inch, and even
at -J an inch from each other when I used larger magnets ; and
in the case of repulsion, the change in the law occurred at
much greater distances, especially when the forces of the re-
spective magnets were materially different.

When soft iron is attracted bv a magnet, the law changes

B2

4 R. W. Fox on Magnetic Attraction and Repulsion.

at a smaller distance than when two magnets attract each
other; but when soft iron is made to repel a magnet, by being
in contact with the corresponding pole of another magnet,
the law approximates to that of the simple inverse ratio, even
at very considerable distances; indeed, in this case the law of
the inverse ratio of the squares scarcely ever obtained at di-
stances at which the magnetic action was very perceptible in
the method which I adopted to ascertain these forces ; and
when they were brought near each other, the repulsive force
rapidly diminished, and ultimately became attractive. This
also occurred, although in a less degree, when the similar poles
of two magnets acted upon each other, if they materially, or
even moderately differed in intensity.

The attraction under these circumstances at the commence-
ment seemed to be in the duplicate inverse ratio, and on the
magnets being brought nearer together, in the simple inverse
ratio, of the distance.

It may here be observed that the force of attraction was
considerably greater when the edges only of the magnets were
in contact, than when their whole surfaces were together,
which is perhaps attributable, in part at least, to the contact
being more complete in the former case than in the latter.
Hence it seems that the small magnets I employed lost one
half their force at the distance of about ^ ife otn °^ an lnc^t olle
quarter at y^^th, &c.

It is well known that pulverized magnetic iron, or iron
filings, will diverge at each pole of a magnet; and I found that
on making two dissimilar poles approach each other, this di-
vergency was not changed till they were brought within
certain degrees of approximation, in fact, sufficiently near to
produce the change in the law above mentioned : the diver-
gency then diminished, till the fibres of powdered loadstone
became parallel to each other, and to the axis of the attract-
ing poles, and so they continued till the magnets were in ac-
tual contact (see figs. 1. and 2.). This experiment seems to
afford distinct evidence of the change which the magnetic
elements sustain, and sufficiently explains the immediate
cause of the alteration in the law of the attractive force which
has been noticed.

When similar poles are gradually made to approach each
other, the divergency of the adhering particles of loadstone is
sooner disturbed than in the case of attraction, it being more
and more increased, till the ferruginous filaments are repelled
at nearly right angles to the axis of the magnet ; and if the
magnets differ much in force, the filaments attached to the
weaker one are so far driven back as to become nearly paral-

R. W. Fox on Magnetic Attraction and Repulsion, 5

lei to its axis, the ends being actually reversed (see figs. 3
and 4.) Under these circumstances they attach themselves

Fig. I.

Fig. 2.

Fig. 3.

&> W

Fig. 4.

I

to the stronger magnet, and afford a very simple explanation
of the cause of the rapid diminution of the repulsive force,
and the change to attraction which takes place between mag-
nets of unequal intensity whilst they remain in these relative
positions. The appearances assumed by the particles of load-
stone may also be exhibited by strewing them on paper, glass,
&c, under which magnets have been previously fixed at pro-
per distances from each other, and gently tapping the surface,
till the arrangement is effected.

I am disposed to regard the magnetic curves around the
magnet as induced towards its surface, and not thrown out
from it, the magnetic elements without, having the same pro-
perties as those within the magnet, and the opposite poles in
both cases alternating with each other throughout the whole
series. Hence a magnetic circuit is formed, and the tension
thereby produced between the opposite poles of a magnet
may essentially contribute to maintain its intensity. This

6 li. VV. Fox on Electrical Action.

tension, added to the reciprocal lateral repulsion of the ter-
minating poles of the magnetic elements, must, I conceive, im-
part to the different series of them within a magnet, a curvi-
linear arrangement, the convex sides of the curves being turned
towards its axis; and the very tenacious manner in which the
particles of loadstone so long retain their divergency at a pole
of a magnet, when strongly attracted by another magnet, is,
I think, only to be explained by a reference to this reciprocal
repulsion of the elementary poles, and the tension produced
by the external magnetic curves.

That these magnetic curves extend to an extraordinary di-
stance from a magnet, may be easily proved by their sensible
action on a very minute and delicately suspended needle,
which has been neutralized wifh respect to the directive force
of the earth's magnetism. On using this test I found that a
magnet, 3 inches long and y^th of an inch in diameter, was
invested with a magnetic sphere, (if I may use the expression,)
which occupied considerably more than a million times its own
bulk, ample allowance having been made for the space filled
by the magnetic curves round the suspended needle itself.

This fact, taken in connexion with the rapid decrease of
the force of a magnet at very minute distances, and the inap-
preciable change in the earth's magnetic intensity* at the
greatest distances above and below its surface which have
been examined, go far to show that the influence of the ter-
restrial magnetism may probably extend to a vast distance
from our globe; and if the magnetic forces be common to
the planetary system, the remarkable uniformity in the places
of the nodes of most of the planets in relation to the plane of
the solar equator may, perhaps, be referred to their agency.

I am unwilling to conclude this communication without re-
marking, that the fact I have stated relative to the particles
of loadstone attached to the end of a magnet having their

* From numerous experiments which I have made at various times, in
addition to what others have done, I have no doubt of the fact of there
being very small apparent temporary fluctuations in the terrestrial magnetic
intensity by day, and occasionally by night ; although these changes may
be due merely to variation in the magnetic dip. Among the local affections
of the magnetic needle, I will mention one instance which my relative
Arthur K. Barclay has communicated to me. In a tour of pleasure which
he last year took through Italy, Sicily, Greece, Turkey, &c, he kindly
made, at my request, many observations with a horizontal needle de-
flected by a magnet in a fixed relative position; and at the base of Trizzat
or the Cyclops Rocks, he observed a deflection of 24°, whereas at their
summit it was 30°. The former consists of columnar basalt, and the latter
of sandstone. My friend repeated these observations several times with
the same results. At Messina, Catania, &c, the deflection of the needle
was also 30°.

R. W. Fox on Electrical Action. 1

poles reversed on the approach of the similar end of another
stronger magnet, seems calculated to throw light on the oppo-
site electric relations acquired by two bodies when brought
into mutual contact; for, assuming that the electric elements,
like electrified bodies, possess opposite polarities both of at-
traction and repulsion, is it not reasonable to believe that,
like the magnetic elements, those electric poles least tenaci-
ously retained in one body, or most energetically opposed by
similar poles in another body, will turn from them, and even
be actually inverted, in order to adjust the balance of forces
between the positive and negative electricity in the two bodies ?
This appeared to me to be a necessary consequence of mag-
netic repulsion, and the attraction acting on the opposite ele-
mentary poles, before I had ascertained the fact; and I think
that the same argument will apply with nearly equal force to
electric repulsion and attraction, and the cause of a very ob-
scure phenomenon may, in this way, be simply explained.

Hence it seems to follow, that the direction of the elemen-
tary poles may be sufficient to determine the positive or nega-
tive character of electricity in all cases of electrical develop-
ment ; and supposing the mode of elementary action already
noticed (viz. the reversing of the poles,) to prevail throughout
a voltaic circuit, pulsation would be produced, and probably
an actual rotation of the electric elements. Such rotation
would account for the appearance of opposite currents ; and
upon the whole, it seems to me that this hypothesis is calcu-
lated to afford simple and satisfactory explanations of many
of the phenomena which electricity presents, — especially its
powerful effect on compound bodies, and the transfer of their
constituents to the opposite electric poles, — whilst it does
not demand from us the admission (in the case of voltaic
electricity,) of continuous currents of immeasurable velocity,
and transferring almost inconceivably large quantities of elec-
tricity from one body to another.

It may, perhaps, be well for me to state more fully my
views of the manner in which simple electric elements, similar
to, or identical with, the magnetic elements, may unite with
matter, and exhibit electric effects in consequence of their
natural relations being disturbed, my object being merely to
offer some examples, without insisting upon them, for the pur-
pose of showing that the elementary action and rotation I have
suggested may enable us to explain many phenomena better
than the commonly received hypothesis of electric " currents"
in rapid circulation, such, for instance, as the definite action
of electricity, which has been so clearly demonstrated by our
first experimental philosopher.

8 R. W. Fox on Electrical Action.

If we suppose the positive electric poles to adhere to, or
have an affinity for, the atoms of oxygen, and the negative
poles for the atoms of hydrogen, the external or acting poles
which surround these atoms will, on this hypothesis, possess
opposite properties to the adhering poles, and impart to oxy-
gen negative, and to hydrogen positive characters.

Between these strong opposite affinities, the force of elec-
trical attraction or adhesion to the atoms of matter may be
variously modified, according to the nature of the latter.
Hence atoms may act on each other in consequence of their
electric properties, and have these properties modified, and
in some cases even reversed, by the inversion of the poles
when acted upon by other atoms around which the electricity
is more energetic and decided. Electricity excited in bodies
by induction will illustrate this hypothesis; and the apparent
anomalous chemical compounds which so often occur, such,
for instance, as oxygen or hydrogen with the same simple
elements, may serve as examples.

In the case of voltaic action the atomic electric affinities may
be partially superseded, and an uniform direction simulta-
neously imparted to all the corresponding elementary poles in
the circuit, an undulatory motion, or actual rotation of tWse
elementary poles, being generated by their reaction.

Fig. 5. may illustrate how a rotatory motion of the electric
elements might operate in producing decomposition.

Fig. 6.
O O O • O Hydrogen.

® 0 & 0 Oxygen.

O O O O Hydrogen.

© ® B • Oxygen.

Let the shaded circles (fig. 5.) represent atoms of oxygen, and
the unshaded ones those of hydrogen, included within the vol-
taic circuit; and let the straight lines denote the electric ele-
ments with their negative or oxygenous poles outwards, and the
zigzag lines those having their positive or hydrogenous poles
outwards. In this case, the electric elements xxx are in the

R. W. Fox on Electrical Action. 9

natural order of their affinities with respect to the atoms a e9
im, and wo, whilst the electric elements at zz, are reversed
with respect to e i and m n, the former atoms being made to
approximate, and the latter to recede from each other, even-
tually giving rise to a semi-revolution of the atoms around
their common axes as shown by the arrows.

The relative position of the different atoms in water and
other fluids must, I think, have reference to their comparative
weight, or downward tendency.

Fig. 6. may illustrate this idea, in which a series of atoms
of oxygen are placed under a similar series of atoms of hy-
drogen ; for they cannot, I conceive, under any circumstances,
alternate horizontally with each other.

It is possible that the state of fluidity may be due to an ex-
cess of one of the electric polarities over the other, thereby
preventing the atoms from approaching within certain di-
stances ot each other.

Now, if we again refer to fig. 5. the directions of the arrows
exhibit a transfer of the hydrogen through the upper portion
of the circle, and the oxygen through the lower; because in
this case it is assumed that the decomposing surfaces are
bounded above, by the atoms of oxygen, and below, by those
of hydrogen. They cannot, however, in either case be readily
carried beyond one half of a revolution, because they would
then be respectively opposed by atoms similar to themselves;
but the electric elements, on their quitting the atoms, will not
be prevented by their polar affinities from completing their
revolutions, and returning to their previous direction in readi-
ness to renew the operation with other atoms.

The relative positions which I have supposed the different
atoms in fluids to assume, may tend to impart a definite cha-
racter to electrical action ; and as it is not easy to imagine that
the electric elements will move with an equable velocity du-
ring the whole of their revolution, if they are charged with
atoms of matter during the performance of one half of it only,
or that the time required to combine with, and to disengage
themselves from the atoms will be precisely the same, it seems
to follow as a probable consequence that voltaic electricity
may act on magnets by virtue of an excess of force or influ-
ence in one direction over another.

In the case of thermo-electricity, likewise, the time required
to disturb and restore the natural arrangements of the elec-
tric elements may materially differ.

On the hypothesis that the magnetic elements Jiave their
opposite poles alternating with each other throughout the
curves which unite the two ends of a magnet, it is not difficult

Third Series. Vol. 5. No. 25. July 1 834.. C

10 R. W. Fox on Electrical Action.

to understand that if these curves are interrupted and broken,
and the magnetic elements coerced from their natural posi-
tion by the approach of an electrical conductor, such a reci-
procal action must occur between the magnet and conductor
as will cause them, if freely suspended, to assume some other
relative positions, the uniformity of which may be governed
by the arrangement of the magnetic elements with respect to
each other. The opposite poles of the latter may overlap
each other, for instance, in one uniform manner so as to de-
termine them towards a tangential position with respect to the
axis of a magnet when acted upon by an electrical conductor:
the spiral form, and perhaps some other forms, might im-
part to them this tendency. The same reasons may explain
why a magnet does not produce electricity in a metallic wire
when moved in the direction of their common axes, as the
opposite poles of a magnet, in this case, have a tendency to
counteract each other's influence.

Many phsenomena in electro-magnetism seem to counten-
ance the probability of a rotation of the electric elements, such
as the rotation of mercury, water, &c, when under the joint
influence of electricity and magnetism. There is also a me-
chanical fact, which I published some time ago in the Journal
of the Royal Institution, and which, perhaps, may be consi-
dered as favouring the opinion of the rotatory motion, or rather
tendency, even of common electricity, viz. that when a needle or
any sharp-pointed instrument rapidly revolving round its own
axis is made to pierce a card, a bur is raised on each side of
the card precisely similar to the effects produced by an electric
discharge*. Moreover, the analogies afforded by the apparent
undulatory motion of light and sound, seem to favour the
opinion that a corresponding action exists in the case of elec-
tricity.

Note. — Since I have completed the experiments above re-
ferred to, and, indeed, written the greater part of this paper, a
friend of mine has sent me W. S. Harris's paper on the laws

* I do not mean to use this mechanical illustration as an argument in
favour of a complete elementary rotation in the case of an electric discharge
from a Leyden jar, for a semircvolution of the electric elements might, per-
haps, suffice to produce the burs; and if we assume that the opposite elec-
tric poles attract each other on either side of the glass, such a partial ro-
tation, or. mere undulation of the elements in the series or circuit, when a
conductor is applied, seems to he all that is required to restore the natural
arrangement and equilibrium of forces. The burs might possibly, however,
be produced by the meeting of the opposite undulations at the card. The
same explanation may be given of the common electric spark, under or-
dinary circumstances, as of the electrical discharge from a Leyden jar :
thus presenting a marked difference of action from what I have supposed
to exist in the cases of voltaic, and thermo-electricity.

Mr. Fairbolme on the Falls of Niagara. 1 1

of magnetic forces, inserted in the Transactions of the Royal
Society of Edinburgh, and I find that this gentleman has
noticed a change in the law from the inverse ratio of the
square to the simple inverse ratio of the distance, when two
magnets were brought near each other; but the greatest de-
gree of approximation he has given is ^th of an inch. The
magnets he used were much larger than mine.

II. On the Falls of Niagara; with some Observations on the
distinct Evidence which they bear to the Geological Character
of the North American Plains. By G. Fairholme, Esq.*

TT has been well remarked by Captain Basil Hall, in the
■*- minute and luminous description which he has given us
of these celebrated falls, that the river on which they occur
is unlike any other stream with which we are at present ac-
quainted. It is at its full size from the first moment of its ex-
istence ; and although it contains more water than almost any
other river, at the same distance from the sea, it is no larger
at its mouth than at its commencement. Its course, too, in-
stead of being of vast extent, proportional to the body of
water of which it consists, is not more than about 36 miles.
This anomaly is, however, at once explained when we con-
sider that the Niagara is but a communicating link between
two of the great American lakes ; and that in its short and
turbulent course, it has neither time nor space to acquire
nourishment from subsidiary streams.

It is a common remark of strangers who are proceeding to
view this wonderful cataract that it seems unaccountable how
such a phenomenon can exist in a country which appears, on
all sides, to present so level and unvaried a surface. In passing
down the river from Lake Erie, the banks, thickly clothed
with forests, seem on a perfect level with the surface of the
water, and the general tameness of the scenery is not such as
is well calculated to introduce the traveller to so speedy and
violent a change. In approaching in a cross direction, the
roads also pass through level and extensive woods, as little
indicating a change of surface; and it is only on approaching
from the side of Lake Ontario, and in passing up the stream,
that the gentle inclination of the country which has given rise
to the cataract is distinctly perceptible.

When we consider, indeed, the nature of this country, and
view it on that great scale which alone is suitable to its vast
expanse, it will be at once acknowledged that the whole globe
may be passed under our review, without exhibiting any si-

* Communicated by the Author.
C 2

12 Mr, Fairholme on the Falls of Niagara

milar index to the length of time which has elapsed since the
first commencement of the present state of things on the sur-
face, and consequently having so direct and simple a bearing
on the geological character of the district in which it is found.

It is perhaps not so well known as it ought to be, that al-
most the whole continent of North America consists of vast
plains, composed of secondary strata of various kinds; and
that calcareous formations in a horizontal stratification form
the leading characteristics in the geology of that country.
The prodigious lakes of Canada and the United States are
formed by the easy and gentle undulations of these secondary
strata; and the sea-like extent of these freshwater basins,
together with their generally low and swampy shores, exactly
correspond with the boundless extent of plain which sur-
rounds them on every side. The very circumstance of the
rivers of North America being navigable for so great a propor-
tion of their length, is sufficient to show the nature of the great
steppes through which they take their easy course towards
the ocean ; and the rapids, which form so interesting and
picturesque a feature in the inland navigation of the New
World, are obviously occasioned by those breaks and inter-
ruptions in the superficial strata for which calcareous forma-
tions are so remarkable.

It is to one of these interruptions in the general level of
that part of the world that the cataract of Niagara owes its
origin. Two vast plains, or steppes (as they are termed in the
North of Europe), extend themselves in different directions.
One is spread over Upper Canada and New York towards the
north, while the other embraces the shores of Lake Erie and
its surrounding States towards the south-west. Between these
great plains there is a considerable difference of level ; and as
the former is lower than the latter, all the waters which are
drained from the one must experience a fall, more or less vio-
lent according to the nature of the line of demarcation over
which they must pass, before they can subside into the ge-
neral level of the other.

In this particular case it happens that this line of distinc-
tion between these two plains is situated longitudinally be-
tween the two great lakes of Erie and Ontario, which are not
further removed from each other than about 36 miles ; and as
the difference of level is spread over an easy slope of 10 miles,
and does not amount to more than 330 feet, (or 1 foot of rise
in 160 feet of length,) the variation in the surface is so imper-
ceptible, unless in the neighbourhood of the rivers, that it is
not easily detected by a common observer in passing through
the country.

This state of the case will be more clearly understood

as illustrating the Geology of North America. 13

by the following section, in which the difference of level in
the two lakes is exhibited, although, of course, on a scale of
height altogether disproportioned to the extent of country over
which the declivity is spread. This fall of 1 foot in 160
would not be thought remarkable in any inland stream of
common size ; but in the case of such a vast body of water as
the Niagara contains, (which forms a large proportion of the
whole fresh water of the earth, and has been calculated at one
hundred millions of tons per hour,) the action, when once set
in motion, must be enormous; nor can we feel surprise at the
powerful effects which it produces, and on which I am now
about to remark.

< — \>Ehft^--Trfo>/y>'y^r-e'^^v

3 6 12 24 36 miles.

A. Lake Erie.

B. The rapids above the cataract, having a fall of about 55 feet.

C. The falls of Niagara 160

From C to Queenston, D, is about 7 miles of violent rapid,

gradually subsiding, and having a fall altogether of 115

Total "330 feet.

The very trifling fall in the navigable parts of these 36 miles is not here
taken into account, but may be 2 or 3 feet of the above number. They
extend from A to B, and from D to E, or Lake Ontario.

But first, in order more clearly to illustrate the nature of
the country and the situation of the cataract, I shall quote a
short passage from Captain Hall's interesting account of it,
which is in itself perfectly clear, and has been corroborated
to myself by the oral testimony of my friend Sir Howard
Douglas, whose intimate acquaintance with the locality, and
whose acute discrimination on all such subjects, no one will
dispute.

" In the first part of the course of the Niagara, this river
slips quietly along out of Lake Erie nearly at the level of the
surrounding flat country; so nearly so, indeed, that if by any
of those causes which swell other rivers, but have no effect
here, the Niagara were to rise 8 or 10 feet perpendicularly,
the adjacent portion of Upper Canada on the west, and of the
State of New York on the east, would be completely laid
under water. After the river passes over the falls, however,
its character is immediately and completely changed. It then
runs furiously along the bottom of a deep wall-sided valley,
or huge trench, which seems to have been cut into the horizontal
strata of the limestone rock, by the continued action of the
stream during the lapse of ages. The cliffs on each side are,

14? Mr. Fairholme on the Falls of Niagara

at most places, nearly perpendicular, without any interval
being left between them and the river, or any rounding of
the edges at the top ; and a rent would seem a more appro-
priate term than a valley*. Above the falls, therefore, that
is, between them and Lake Erie, there is literally no valley at
all, as the river flows with a gentle current, and almost flush,
as seamen call it, or level with its banks; while below the ca-
taract, the bed of the river lies so deep in the earth, that a
stranger unprepared from these peculiarities, is not aware
of there being any break in the ground at all, till he comes
within a few yards of the very edge of the precipice."

Such is the clear and concise statement of Captain Hall ;
but it must be understood that this deep and precipitous
trough does not extend much further than Queenston Ferry,
7 miles below the fall, and where the current flows at the rate
of about 3 miles an hour. The sides, during the whole of
this descending course, become gradually lower, until at
length the river and its banks, on approaching Lake Ontario,
reassume the same level and peaceful character which had
been remarked for nearly 18 miles below Lake Erie, until
disturbed by the rapids above the fall.

It is clear, therefore, that the waters of the whole of the
upper lakes, in seeking their level in the ocean, have to de-
scend from the higher to the lower plain ; and as this descent
does not take place by a wide valley, such as forms the usual
channel for most other rivers, it is equally obvious that a
period once existed, when these waters first began to overflow,
and when they must have made their way over the upper sur-
face of the country in the form of a great rapid, (see the dotted
line from B to D of the section,) and that the violence of this
superficial action on secondary strata of a horizontal form,
has gradually occasioned a cataract, which would naturally
commence near the base, and which has in the course of
many ages gradually worked its position backwards, until we
now find it nearly at the greatest possible height which the
nature of the ground will admit of. If this point be admitted,
it is equally obvious that a continuance of the action must
occasion a continuance of the effect, and that a time must
consequently arrive when the whole barrier between the two
lakes will be intersected. This period is, of course, very re-
mote f; but it is not the less certain and unavoidable, if the

* A trough would, perhaps, be a more suitable term than either, being
the result of continued action. A rent implies a sudden effect of some
violent convulsion, of which that entire district offers no one instance.

t The distance being 21 miles from the present cataract to Lake Erie,
and the rate of action being about 4 feet per annum, the time necessary
for this great natural operation will be 27,/20 years. As the fall will,

as illustrating the Geology of North America, 15

causes now in force continue to exist. The consequences
will be most extensive and disastrous, more so, indeed, than
any natural event within ihe range of history. The whole of
the upper lakes of North America, which more resemble seas
than inland collections of fresh water, will then be lowered
by nearly 300 feet, and the low countries between Lake On-
tario and the Atlantic can scarcely escape from being swept
at once into the ocean.

But it is not my present object to look at this subject pro-
spectively. We shall find the retrospect equally distinct, and
infinitely more instructive, and I shall therefore now resume
that view of the matter.

No one who has examined and described the phenomena
of Niagara has ever doubted that the section of the strata has
been effected by the sole action of the continued current; and
we have only to consider the nature of the existing causes
and effects, as exhibited at the cataract and below it, to be
convinced that this is unquestionably the case. Had this cele-
brated fall been situated in the Old World, — for example, in
Italy, in India, or in Egypt, — we should have been enabled to
calculate with precision the rapidity of its retrograde move-
ment, by means of the ancient temples and other buildings
which would probably have marked its former site in remote
periods. Not having this advantage, however, and finding it
situated in a region which, but a century ago, had never been
visited except by the hunter or the roving Indian, we are com-
pelled to adopt as a basis for our calculation the observed
effects now in daily progress, and the evidence of respectable
individuals who have resided for the last 40 or 50 years in
the immediate neighbourhood of the spot.

When Captain Hall was informed, by authorities upon which
he could confide, that the cataract had receded about 50 yards
in the last 40 years, he found great difficulty in giving credit
to so rapid an action, being little short of kfect per annum :
and he was consequently led to a minute examination of the
nature of the rock and the direction of its stratification, when
he at once perceived and admitted that this rate of action had
probably not been over stated. He describes the rock as
calcareous, and the stratification as quite horizontal, as is usual
with such secondary formations. Near the top, the stone is
hard, but as the examination is carried downwards, the solid
stone ceases, and a crumbling shale succeeds at the depth of

however, be higher than it now is when it reaches the top of the rapids,
the action cannot be calculated at so much as it now is, and the United
States on the coast mav therefore safely reckon on a lease of from 30,000
to 40,000 years.

16 Mr. Fnirholme on the Falls of Niagara

about 100 feet; and this softer substance, being acted upon
by constant moisture and a violent current both of air and of
water, is rapidly decomposed, and gradually leaves the harder
beds overhanging their base to the amount of 50 or 60 feet.
This excavating effect produces that species of gallery into
which the more intrepid visitors can enter for about 150 feet,
and in front of which the appalling cataract tumbles like an
agitated curtain. It is clear that this excavating effect cannot
be carried on beyond a certain point; for when the upper
strata are, at length, no longer able to sustain their mighty
load of waters, the whole table rock must give way, and a si-
milar process be again renewed. By such incessant action,
the form of the cataract is constantly changing. Many in-
stances have occurred of late years; and in 1828 a fragment
of rock gave way, and was carried into the abyss, which was
calculated at not less than 5000 cubic yards, producing re-
peated shocks as of an earthquake, which were felt to a con-
siderable distance in the surrounding country*.

The receding of this remarkable waterfall being thus esta-
blished, both by the evidence of facts and by the very nature
of the case itself, the question at once arises as to the length
of time required for executing the seven miles which have al-
ready been completed-, and it is a self-evident fact, that how-
ever long or short this period may be found to be, it must have
commenced at zero; or, in other words, the commencement
of this great natural work must distinctly point out the com-
mencement of the present system of things on the whole conti-
nent of North America ; and, by reasonable analogy, in other

* " The epithet of the horse-shoe" says a recent traveller, " is no longer
applicable to the greater fall. In the progress of those changes which are
continually taking place from the attrition^ of the cataract, it has assumed a
form which 1 should describe as that of a semihexagon." — Men and Man-
ners in America, vol. ii. p. 320.

** Nothing which enters the awful cauldron of the fall is ever seen to
emerge from it. Of three gun-boats which were sent over the falls some
years after the termination of the war, one fragment only, about a foot in
length, ever was discovered. It was found at Kingston, about a month
after the descent of the vessels." — Ibid. p. 328.

The author of u Transatlantic Sketches" says, "The American fall
seems fast assuming the horse-shoe form. In standing under the falls, one
constantly hears the sound of falling rocks amidst the awful roar of the
cataract ; but many of these may have been rolled down the rapids from a
distance, and may not be portions of the rock of the cascade itself."
Vol. ii. p. 155. — This, indeed, is highly probable; but at the same time,
every falling stone at this cataract, even from the rapids above, tends to
forward the great natural section which we are now considering. None
come from Lake Erie, nor from the smooth course of the river for 12 or 14
miles below that lake; and there must obviously always be a rapid in pre-
paration above the fall, and retrograding along with it.

as illustrating the Geology of North America. 1 7

parts of the world also, where the superficies is found to possess
a similar secondary character. This being the necessary re-
sult from our inquiry, no one will probably deny that its bear-
ing upon the science of geology is most important; and that,
in fact, it involves a train of reasoning which must powerfully
influence the theories of that most interesting branch of study.
It has been already stated that the distance from the fall to
Queenston Ferry, where the river has resumed its more tran-
quil and navigable course, is about seven miles, or 37,000 feet;
and if we divide this distance according to the data already
stated, or at the rate of 4? feet per annum, we find that a little
more than 9000 years would be necessary to complete the
section as we now find it. It is scarcely necessary, however,
to point out that such calculation would not be fairly stating
the facts of the case. As we now see the fall, we find that it
has attained within 50 perpendicular feet of the summit level,
and that it is now, consequently, acting upon a vastly greater
resisting body than was at first opposed to it, in the com-
mencement of its labours. By a reference to the section, it
will be seen that the height of the fall must necessarily have
progressively increased, from the very bottom at D, where it
begun as the lower portion of a mere supeifcial rapid, up to
its present elevation of 160 feet; and as the acting force has,
at all times, been the same, while, on the contrary, the op-
posing one has been greatly less, it would by no means de-
monstrate the truth if we took the present rate of action as a
fixed point to calculate from. We arrive at this conclusion by
a natural and obvious line of reasoning, which we should not
hesitate to apply in the case of any great artificial work. In
this difficulty it naturally occurs to the mind to try the ques-
tion by the most approved system of chronology, and it there-
fore only remains to divide these 37,000 feet by the 4000 years,
more or less, which are generally supposed, even by many
geologists (and Cuvier amongst the number), to have elapsed
since the period of the last great catastrophe (geologically
speaking), or the Mosaic Deluge (if we trust to the evidence
of Scripture). We find, then, that by this process a rate of
action, amounting to about 9 feet per annum, would exactly
bring us to this great and interesting point', and it only re-
mains for those who are accustomed to such calculations of
solid measurements to say, whether 9 feet of general average
over the whole space may be admitted to be a fair medium
amount of action. If, by ma- a 37,000 feet.

nual or other labour, 4- feet are § r^HT" - _ I

removed per annum at A, a cube " ^ -t— = ^fst— I B

of the same dimensions would require a little more than 9000
Third Series. Vol. 5. No. 25. July 1834. D

IS Mr. Fairholmc on the Falls of Niagara

years to remove the solid contents at the same rate : but as
in the case now before us, only about half the cube is to be re-
moved^ we may fairly conclude that the work would be com-
pleted in one half the time, or in about 4500 years*.

Having attained this very interesting and remarkable re-
sult, which I cannot help thinking is beyond the reach of
cavil, or of serious dispute, the mind naturally refers to the
probable state of things before the commencement of this great
natural operation ; that is, and necessarily must be, before the
existence of the North American lakes, and before the cal-
careous beds which now cover the plains of that vast conti-
nent were elevated above the sea in which it is admitted they
must have been deposited. We find in the phaenomena of
Niagara one of the most striking corroborations of that evi-
dence which history and the traditions of all lands, civilized
and savage, have handed down to us, and which the fossil re-
mains of animals of the same species, and buried under cir-
cumstances precisely similar on the level of the present sea,
and at 10,000 feet above its surface, so distinctly illustrate.
The theories of many able geologists have been distinctly op-
posed to the fact of the Mosaic Deluge ; and one very talented
author, for whose abilities I have a high respect, has in a late
publication candidly announced, that he has " no hesitation in
saying, that it has never been proved to have produced a single
existing appearance of any kind, and that it ought to be
struck out of the list of geological causes." I make no re-
mark upon this passage ; and I only quote it for the purpose
of showing the opinions of high authorities that are abroad
upon this subject. It will give me the greatest pleasure to be
set right in the arguments which I have ventured to draw
from various distinct, and otherwise unaccountable, sources in

* A cause and effect in some degree similar may evidently be traced on
a large proportion of our secondary coasts, where, though a precipitous
range of cliffs is now commonly found, a regular continuance of the ex-
isting slopes must at some former period have extended to the surface of
the water, and formed the margin of the ocean's bed. We see this clearly
demonstrated wherever such secondary heights have been protected from
the'continued action of the waves, and the aiding corrosion of the atmo-
sphere, by the forms of bays, and the lowness of the sea-beach, common
in such situations. In such circumstances we often find a sloping eleva-
tion in its perfect form on one hand where the sea has never acted upon
it, and with a precipitous cliff on the other, although a long extent of
gradual inland slope assures us that this sudden and precipitous cliff has
not always existed. We can perceive the annual progress of this corrod-
ing action, and if we, therefore, carry on the outline pointed out by the
regularity of the inland slope, until it touch the surface of the ocean, we
shall have a case of gradually receding destruction, extremely similar in
effect, though different in cause, to the remarkable cataract we arc now
considering.

as illustrating the Geology of North America. 19

support of the Scripture statement; and last, though not
least, from the above phaenomena of the greatest of known
cataracts ; and I shall look with some anxiety for a simple
and consistent refutation of the subject of this paper. Jn the
mean time I must confess my own complete conviction of the
importance of these facts to the science of geology. We
everywhere hear of the immense periods, amounting to millions
of years, in which geologists seem to delight to revel. We
hear of a time when the mighty Mastodon and the gigantic
Mammoth, as well as other animals now supposed to be ex-
tinct, lived and died upon the very spots in which we now
find their remains in a shattered and detached state ; we find,
upon the same authorities, that the great plains of the Ame-
rican continent must have been thickly peopled by these in-
teresting animals ; and we derive a sort of mysterious plea-
sure in diving into the recesses of past times, and in pic-
turing to the imagination the state of the present lands of the
earth at periods supposed to be far anterior to the creation of
the human, or of most of the existing animal, races. In the
midst of these pleasing day-dreams we are often disturbed by
the contradictory and stubborn facts which are from time to
time brought to light in opposition to them ; and to crown
the whole, we find our magnificent ideas of the former state
of the American continent threatened with sudden and com-
plete annihilation, by the evidence of Niagara against the very
existence of the plains of that continent above the surface of the
ocean before the Mosaic Deluge.

To such, however, as have viewed this important subject
in the light shed upon it, with a steady and distinct illumina-
tion, by Scripture, this remarkable result is but a new and
powerful link in the mighty chain of facts which, however
shaken, can never be broken. Our minds are preoccupied
with a certain set of theoretical data, upon which the most
glaring, though opposing, facts appear, too often, to have
little or no influence. Such facts must, however, exert, sooner
or later, an increasing force, and must in time lead to a more
consistent and natural (not to say Scriptural) view of things.
Here, for instance, is a fact which seems to bear its own date
and history on its front with almost as much distinctness as
if they had been written in letters of brass, and intended for
an index to the period when the present surface of this and
many other secondary countries first issued from their parent
deep. We have only to cast a glance over the nature of the
great American plains to be convinced that this is the case.
These vast steppes extend from the western slope of the Al-
leghany mountains to the sand plains, a distance of 1500

D2

20 Mr. Fairholme on the Falls of Niagara

miles, and from the northern lakes to the mouth of the Ohio,
a width of nearly 600 miles. They have been so well de-
scribed in the second Number of the Illinois Monthly Maga-
zine, as quoted by Mr. Stuart in his late able work, that I
cannot resist inserting an outline of the statement. These
plains embrace the States of Ohio, Indiana, Illinois, Missouri,
Kentucky, and parts of Pennsylvania, Virginia, Tennessee,
Arkansas, and Michigan, as well as a wild region of about
500 miles wide, lying to the west of these States. No part of
the globe, perhaps, presents so uniform an extent of fertility.
There are no sterile districts, no"rocky or precipitous ridges,
and but few swamps to deform so fair a surface. This unin-
terrupted fertility is stated to arise from the decomposition of
the great limestone pan on which they repose, and which
pan, we have seen, is in part intersected by the action of the
waters of Niagara. This whole level region, though traversed
by numerous rivers, is not a valley, or a system of valleys,
but a real steppe, or plain, over the whole of which there is
but a very slight difference of elevation. The N.E. corner of
the plain near Pittsburgh, in Pennsylvania, is about 800 feet
above the level of the sea ; the plain of Kentucky and Ten-
nessee is about the same height ; that of the Ohio is but little
different; and to the westward of the Missouri and Arkansas
to the sand plains, the same conclusions force themselves
upon us.

The great and numerous rivers which cross these plains,
instead of forming distinct valleys, do but indent narrow
scratches or grooves into the surface, barely sufficient to con-
tain their waters. These river channels have formed a decli-
vity for themselves, and towards their terminations they sink
deeper into the plain : hence the larger rivers appear to be
bordered by abrupt hills of several hundred feet of elevation ;
but this is, in fact, only in appearance ; the tops of these
heights are but the general level of the great plains.

The following short outline of the general geology of these
countries is given in the Magazine above mentioned. " The
formation of these plains is decidedly secondary, reposing on
a horizontal limestone rock, the thick strata of which have
never yet been penetrated, although the auger has pierced in
many different places from 400 to 600 feet in search of salt
water. This limestone is hard and stratified, imbedding in-
numerable sea shells of the Terebratula, Encrinites, Ortho-
ceratites, Trilobites, Products, &c. This limestone pan is ge-
nerally but a few feet below the surface, and supports strata
of bituminous coal and saline impregnations through almost
its whole extent. The decomposition of its parts has fertilized

as illustrating the Geology of North America. 21

this wide region*, and its absorbent and cavernous nature
prevents swamps and moisture from accumulating on its sur-
face. The mineral resources of these plains are unbounded,
and its coal-field would cover half Europe. The coal is pure,
lies above the level of the river channels, and is easily worked.
Iron and lead are also abundant. Salt water is found over
the whole extent, and yields from £th to y^th of its weight in
pure muriate of soda. This salt water breaks out in many
places in the form of springs ; but it is more usually necessary
to bore to the depth of from 3 to 600 feet into the limestone.
Gypsum and saltpetre are found in abundance, and most of
the earths or clays useful in the arts."

There is probably no part of the world of a similar extent
that more completely points out its own history and forma-
tion than these North American plains. We here find re-
posing on a marine formation, the depth of which is unknown,
and which remains in an undisturbed level surface, all the
marks we can desire or expect of diluvial deposits in the form
of deep beds of clay and gravel containing the fossil remains
of the Elephant, the Mastodon, and other contemporaneous
animals ; and also extensive strata of pure vegetable and bitu-
minous coal, as well as the chemical formations of ironstone,
gypsum, lead, &c. From the great extent and level nature
of the original sea bed here laid dry, the diluvial deposits
have also assumed the same regularity of form ; so that the
researches of the geologist are infinitely less complex than in
our own island, where we have, crowded into a small district,
a confused mixture of every description, which has given rise
to much difficulty, and to a wide field of theoretical specula-
tion, contributing largely to give to this interesting study that
doubtful and obscure character of which it is, in fact, unde-
serving, when viewed upon a wide and proper basis. Had
this science taken its rise in America instead of in Italy and
in England, the more enlarged scale of things, and the more
simple nature of the formations, would have led to that corre-
sponding simplicity which true geology possesses. But in the
microscopic views of things which are alone within the reach
of our personal inspection, in the most scientific parts of Eu-
rope, we can scarcely wonder at the extraordinary ideas which
have arisen on this subject, and which have naturally spread
with civilization into other more extensive regions, to which
they cannot possibly be consistently applied. Instead, then, of
making our confined districts the arena of geological illustra-

* This is a point which is more than questionable. The fertility of this
wide region is in great part owing to the alluvial or diluvial soils which
cover its whole extent to a greater or less depth, and in which the fossil
remains of Mammalia unnatural to America are so constantly found.

22 Mr. Fairholme on the Falls of Niagara

tion, and then extending the analogy to the boundless conti-
nents of the earth, would it not be wiser to study this inter-
esting subject on the larger scale, and thus become enabled
to apply it with greater precision to the more confined di-
stricts in which we happen to be placed ? Let us hope that
the theories of geology are not yet so firmly established in the
public mind as to place this more consistent method entirely
beyond our reach. Let us, by such obvious steps as I have
now been endeavouring to establish, go backwards in our re-
searches. Let us first firmly establish the fact of a universal
deluge about the very period denoted by Scripture chrono-
logy. When this great point is admitted, and proved beyond
cavil (which is not supposing too much), let us candidly apply
to such diluvial waters, the full power and action of the tides,
and more especially of the currents, by which our seas are
kept in such continual circulation, and which are a natural
and necessary consequence of the rotatory motion of a solid
globe covered by a fluid ocean. Let this action be supposed
to have continued for the full period mentioned in the record ;
and on the restoration of the whole system, from its preter-
natural to its natural course, let us view the probable and
even unavoidable state of the new dry lands, not upon the
scale of our trifling rivers and floods in England, but upon
that vast and extended scale exhibited on the continents, which
is, however, only clearly pointed out to the mind's eye, by
the idea of the whole earth being surrounded by a boundless
and agitated ocean. We shall then think less than we now
do of some hundreds of feet of stratified aqueous deposits ; we
shall then perceive a consistent reason for our vast coal-fields,
with their vertical witnesses of rapid formation, to which I
have adverted in a former paper. Where the ocean's bed had
been rough and disordered, there we must expect to find a
proportional complication of sedimentary matter. Where, on
the other hand, it was more level and equal, (as in the case
of the American plains above described,) there we shall look
for such results, and such a simple system of stratification, as
are now presented to our contemplation.

We find a distinct index, as to time, in the section worked
out by the cataract of Niagara. We find this section to have
been begun, as it naturally must have been, immediately sub-
sequent to the restoration of order, after the Mosaic Deluge.
We find the river cutting its own course through a marine
formation of an unknown depth, but extending beyond two
hundred fathoms, and which spreads continuously over plains
on which all Europe could be placed ; and, lastly, we find on
the surface of this marine formation, beds of bituminous coal
of the purest kind, and of wonderful extent, together with

as illustrating the Geology of North America. 23

the fossil remains of many animals unnatural to America, but
all of which must have been deposited there at the period
when the waters of Niagara were first set in motion, and con-
sequently they must all have been laid where we now find
their shattered remains by the action of the universal deluge.

It is unnecessary in this place to follow out at greater length
this simple and obvious line of reasoning, or to extend it by
analogy to other parts of the present dry lands of the earth.
No reader who is satisfied of its truth will have any diffi-
culty in applying it to every other district, and especially to
England, where our coal-fields, though less simple, are yet full
of proofs of diluvial action; and where our fossil remains of
land animals can always be simply accounted for upon this
principle, and upon no other that is not beset with difficulties,
and contradictions of the most glaring kind. I shall there-
fore conclude this paper with the testimony of the illustrious
Cuvier to the truth of the point for which I am now con-
tending, although he drew from it very different conclusions.
" I conclude," says he, " with M. de Luc, and with M. Dolo-
mieu, that if there be any fact well established in geology, it
is this, that the surface of our globe has suffered a great and
sudden revolution, the period of which cannot be dated further
back than 5 or 6000 years. This revolution has, on the one
hand, ingulfed and caused to disappear the countries formerly
inhabited by men, and the animal species at present best known ;
and on the other, has laid bare the bottom of the last ocean,
thus converting its channel into the now habitable earth" — •
Disc. Prelim in a ire. *
Ramsgate, July 23, 1833.

Appendix.
Since the above paper was written, several months ago,
a doubt has been suggested to me, by some able observers
of the falls of Niagara, whether the section of the seven miles
down to Queenston from the falls can be properly regarded
as only the half of a solid oblong square, as above stated.
The general slope of the country is supposed to incline down-
wards from the falls, but not in so regular a manner as I had
been led to believe ; and it comes to a more abrupt and decided
termination near Queenston, at what are termed Queens-
ton heights, where the slope is more rapid, and where it
falls into the general level of the great plain of Lake Ontario.

[* Some remarks by the Rev. W. D. Conybeare on Mr. Lyell's estimate
of the time occupied by the retrogression of the falls of Niagara from their
original to their actnal position, will be found in the Phil. Mag. and Annals,
N.S., vol. ix. p. 2G7 ; the subject is also noticed in vol. x. p.. 31 6. Mr. Lyell,
we observe, calculates that the retrogression occupied 10, 000 years. — Edit.]

24? Mr. Fairholme on the Falls of Niagara.

This rapid slope, however, is by no means precipitous: it
extends across the river on both sides, and is covered with
forests and vegetation. It is from this point that the section
made by the river takes its rise ; and instead of so long a rapid
as I had at one time been led to imagine, I have now reason
to believe that the primitive rapid was chiefly over the super-
ficial slope of Queenston heights, and that the form of the
section would therefore be more correctly drawn thus,

than as given in p. 17.

It may be urged that this addition to the work to be per-
formed must make a vast difference in the time required for
the execution of it. This is not the result, however, in this
case, although in common circumstances it might be so ex-
pected. But it has been observed by the same persons to
whom I am so much indebted for this correction, that in the
case of Niagara, my computation, as to time, has every ap-
pearance of being exceedingly correct. Not only is the deep
ravine already cut out much narrower below the falls than at
the cataract itself, but the crumbling shale which forms the
lower part of the rock at the falls, forms, lower down, a much
greater proportion of the whole rock. At the falls, the depth
of the solid limestone is 70 feet, the whole of the remainder
being of the soft nature of shale ; towards Queenston, the
superincumbent limestone is much thinner, and the action of
the water upon the whole body of the rock must have been
consequently much more rapid.

Again, as to the actual cubic measurement influenced by
the river's action lower down, as compared with what it now
is at the falls, there is a difference so great, that it would
compensate for even a greater additional cubic body of rock
than I have now found it necessary to add to my former
calculation. The width of space over which the river's action
is now spread, including Goat's Island, is about 3500 feet,
and over this wide space, we find that the fall is retrograding
at the rate of nearly four feet per annum. But the medium
width from the falls to Queenston is not more than about
\Z00 feet, in some places more, in some less; and when this
greatly inferior width is added to the softer nature of the
rock already alluded to, we cannot doubt that the action was
much more rapid in the early periods of the section, since the
quantity of water must always have been what it now is.

We might, therefore, even in the absence of all other evi-
dence, safely assume that the time necessary for the comple-
tion of this vast natural work could not be extended much
above 4000 years. When this remarkable fact is corroborated,

On the alleged Greek Traditions of the Deluge. 25

however, by an exactly similar result in regarding the phe-
nomena of our own and other sea cliffs, acted on by the sea,
which will form the subject of another paper, all doubt on
this head that may have existed must surely be for ever re-
moved.

III. On the alleged Greek Traditions of the Deluge.
By the Rev. John Kenrick, M.A.

[Continued from vol. iv. p. 420 ; and concluded.]

T^TE have now reached the time when the Greeks, having
" been brought into much more extensive and leisurely in-
tercourse with Asia than they had enjoyed before the time of
Alexander, had the opportunity of comparing their own fables
with those of the Asiatics, and of remodelling or adding to their
own, in order to give them a more imposing appearance, or to
maintain the claim of originality in everything, to which in
earlier times they were far from pretending, and which is, in-
deed, without any foundation in history. We cannot, there-
fore, appeal with confidence to what we find in Greek authors
from this time forward, even as proving the existence of a
Greek tradition ; still less can Ovid's version of the story be
appealed to. " A mesure," says Cuvier, " que l'on avance
vers des auteurs plus recens, il s'y ajoute des circonstances de
detail qui ressemblent davantage a celles que rapporte Moise.
Ainsi Apollodore donne a Deucalion un coffre pour moyen de
salut; Plutarque* parle des colombes par lesquelles il cher-
chait a savoir si les eaux s'etaient retirees, et Lucienf des
animaux de toute espece qu'il avait embarques avec lui," etc.
Yet he had written in a preceding page, " Pour peu que l'on
suive la maniere dont le deluge de Deucalion a ete introduit
dans les poemes des Grecs et les divers details dont il s'est
trouve successivement enrichi, il devient sensible que ce n'etait
qu'une tradition du grand cataclisme, alteree et placee par les
Hellenes a Pepoque oii ils placaient aussi Deucalion." If we
find ingredients in the stream at a distance from the source,
which it has not when examined nearer to the spring, the
natural conclusion would seem to be that it has acquired
them on its way, not that they were there from the first, in
some mysterious state of delitescence.

* Pint. TLoTi^tc ray tuuv (pQovip.. § 13. viii. 930, ed. Wyttenb.

-f It is doubtful whether Lucian were the author of the treatise De Ded
Syra, in which this mention of the flood occurs: what is more important
to our purpose is that the writer, whoever he was, probably was an Asiatic
Greek.

Third Series. Vol. 5. No. 25. July 1834. E

2G The Rev. John Ken rick on the alleged

The traditions of the flood of Ogyges will not detain us
long. Even his name, as a king of Attica, does not occur in
any extant author before the time of Alexander, and for most
of what we know of him we are indebted to the Christian
chronologers. A passage in Eusebius, Prcep.Evang. x. p. 10.
might lead us to conclude that the flood in his time had been
mentioned by Acusilaus, i. e. in the beginning of the 5th cen-
tury B. C. : 'Atio 'flyuyov tov nap exeivo/g (' Att ixo~i$) avTO^Sovos
iriTTEvQivTOSf 1$ o3 ysyovsv b (J.eya§ xa» TtpwTOc, sv tyj 'Attixyj xara-
xAu<7ju.0£ <£op«;vea>$ 'Apysiwv (2a<Ti\suovTO$, oo§ ' Axouarl\ao$ l<rropsi9
l*>zXPl *?***m ' O Aupn a&o j, x.t. A. But it is difficult to know
what were the exact words of the original, and it may be that
the mention of the deluge proceeds from Eusebius himself,
especially as Syncellus has the following passage, (p. 119. ed.
Bonn.): coctts oullv a£»Ojw,vrjjU.o'veuTOvr' ' E\\v\<nv \o~T0pi\Ta\ npb 'flyvyov,
Tt\r)v <Popooveu)$ tov o-vy^povlo-avTO; aura; xai 'hayov tov <Popwveoo$
TrcLTph$i be, 7rpwT0$ "Apyovg e^acnAsucrsi/, oo$ ■ ' Axovo-l\ao$ Wropei,
I am therefore inclined to think that Acusilaus is properly to
be considered only as an evidence to the dominion of Phoro-
neus at Argos; or at most to the synchronism between him
and Ogyges. The name of Ogyges never occurs in Attic
poetry, nor is there any trace of him in the remains of Attic
art. Philochorus, who wrote his Atthis about 260 B.C.
seems to speak of Ogyges as king of Attica, according to the
quotation from Julius Africanus in Syncellus, (p. 281. ed.
Bonn.) : Tov yap 'flyuyov 'Axtouov, y) to, nKao-cro^sva toov ovo^octoov
ou&e ysveoSou <Pyjo-)v 6 <Pi\o%opoc. Yet even here I feel by no
means certain that tov 'flyuyov are not the words of the chro-
nologer*. There is no mention of Ogyges in the Parian
marble, which was engraved about the time when Philochorus
published his Atthis.

* If any one should think that this is an attempt to get rid unfairly of
a witness, let him see what a license this same chronologer allows himself.
Mifivnreti li xxl ' HQohorog rvjs <x7roaTotoixs tuvtyi; (the defection of the Jews
under Moses) ku\ ' kpaoiog \» tyj fevTtgct, T^ona Zi nut ku\ 'lovluiau, eu
To?; TTS^tTifAuofcii/otg otvrwg KctTct^tOfiai/. Jul. Afr. ap. Sync. p. 281. If we
had no other knowledge of the Second Book of Herodotus than from this
passage, could we have ventured to doubt whether the name of Amosis,
if not of the Jews, occurred in it ? Heyne, Apoll. vol. ii. p. 320, on the
strength of this passage in Jul. Afr., supposes that something has dropt out
of the text of Apollodorus, at the beginning of 3. 14. in which, if we had
it, we should find something about Ogyges. Yet the actual commence-
ment of that chapter, KtK(>o\p ui/ro^cou tjj$ ' ArTtscqc t&ccafaevas ir^a-tog, x,otl
tvjv yw, Tr^oTinov "hsyopiuriv ' Aktvjv u,($ suvtov Kex.^07rixu uvopuosv, does
not look as if it had ever been preceded by an account of Ogyges, a prede-
cessor of Cecrops. With the same inaccuracy Syncellus (i. 238.) makes
Plato in the Timaus speak of " the flood in. the time of Ogyges," though
Plato never mentions his name.

Greek Traditions of the Deluge. 27

I have given in the Philological Museum, ii. p. 348, my
reasons for thinking that the name and story of Ogyges be-
long properly to Bceotia* Whether I am right or not in the
interpretation which I have given to his name, the fact that
traditions respecting him were connected with Bceotia, and
that we have no proof that they were so with Attica, remains
the same. As to his flood, till some more decisive passages
are produced than those which have been given above, I must
be allowed to doubt whether we have any proof that either
in Bceotia or Attica there was any tradition respecting it.
Pausanias, says, Bceot. 5., that Thebes derived the name of
Ogygian, which many of the poets had given it, from an au-
tochthon, Ogygus, king of the Hectenes, and that this people
perished Koi^ooln voa-co.

I have now to inquire how the popular belief among the
Greeks upon the subject of a flood in the time of Deucalion
is to be accounted for. Three suppositions may be made,
The progenitors of the Hellenes brought with them from Asia
a tradition of the flood of Noah, which they localized in their
own country, by attributing it to Thessaly. This is the com-
mon opinion ; and it is the more easily adopted because, as
we know nothing whatever of the tribes from whom the Greeks
originated, we pass per solium from Thessaly to the plain of
Shinar, and nothing seems simpler than that they should pre-
serve a tradition of a recent and impressive event. But let us
consider chronology a little. According to the Hebrew text
the deluge is placed about 2300 b.c. ; but historical inquirers
are beginning to feel the inconvenient limitation of time which
this occasions, and adopt the Septuagint reckoning, which will
carry it up to 3500 B.C. Now we have not found any traces
of this tradition in Greece earlier than the commencement of
the 5th century before Christ. Here is then a period of 3000
years, during which we must suppose it to have been preserved
in the minds of a race who, if their own tradition about Pro-
metheus is to be believed, (and it is found in earlier authors
than that of Deucalion,) had not even the use of fire among
them. It would be too much to say that such a transmission
is impossible. Those who believe that Ammonian and Cu-
thean priests marched from Chaldaea to all parts of the world,
bearing diluvial traditions and helio-arkite symbols, may not
even find it improbable ; but let the linguist and the ethnogra-
pher reflect on the changes and vicissitudes through which the
ancestors of the Hellenes must have passed, and they will be
startled, I think, at the demand made upon their belief. No-
thing could make the preservation of a tradition in these cir-
cumstances credible, but such a close resemblance as pre-

E2

28 The Rev. John Ken rick on the alleged

eluded the idea of accidental coincidence, manifesting itself
at a time when there could be no communication with a fo-
reign source. We have not found either of these conditions
fulfilled in our inquiry into the traditions of Deucalion.

The next hypothesis which suggests itself is that they are
the real reminiscences of some local flood, such as a country
abounding with lakes and mountains, bordered by the sea,
and exposed to earthquakes, must often have undergone. It
is certain that the Greeks had no tradition of a general de-
luge. Apollodorus, whose description of the flood of Deuca-
lion bears some resemblance to Noah's flood, says, ra ixro$
'Jcrfl/xoO xai ris\o7rovvY)<rov (tvvb^uQyi Tra'vra, on which Heyne ob-
serves, " in Peloponneso diluvii memoria nulla," which is sub-
stantially true, although Dionysius of Halicarnassus (i. 61.)
mentions that some of the Pelasgians left Arcadia for Samo-
thrace in consequence of a flood which deprived them of part
of their land. This is also true of Attica, though Pau-
sanias speaks of a chasm (i. 18. 43.) in the temple of Jupi-
ter, through which the water of Deucalion's flood (sTro^piu)
had run off. This may seem a presumption in favour of
a real tradition of an inundation produced by an earth-
quake, or some similar cause. Yet even in this modified
form, the opinion of a real tradition appears to be open to
many of the objections urged against the former hypothesis.
If chronology is to be applied to these matters at all, Deuca-
lion's flood cannot be placed later than the 15th century be-
fore Christ : we find the first mention of it in the 5th. We
must not judge of the probability of such a transmission by
the fact of traditions having reached our own times from those
of the Roman empire: the use of writing has never been lost
in Europe. Besides, all the circumstances of the story are
evidently fictitious. No inundation could have floated or
driven Deucalion to the top of Parnassus without deluging
all the low lands of Greece ; and it will then require to be
accounted for, how this event has left no tradition in the other
parts which must have suffered from it. If we take away
from the story Deucalion and Pyrrha, the ark, the resting on
Mount Parnassus, the reproduction of the human race by the
casting of stones, what remains to be the matter of a tradition?
The simple fact of an inundation, — a natural phenomenon
which the imagination can multiply and magnify as much as
it pleases, and place in any age it thinks fit. The only rea-
son for admitting such an extraordinary transmission of a fact,
through ages which have preserved no memorials of their own
history, would be the impossibility of conceiving how such
a thing should have been invented, if not true. But unless

Greek Traditions of the Deluge. 29

the event, though within the laws of nature, were beyond
men's knowledge and experience of them, the more likely it
was to happen, the more easy it was to suppose it happening,
to adorn it with circumstances, and to fix it to time and place.
The vulgar, too, draw much more liberally on extraordinary
causes to explain appearances, than a philosopher allows him-
self to do.

If we are to receive the account of Deucalion's flood as the
tradition of a real occurrence, it will be difficult to say why
we should not do the same with regard to other Greek fables.
But of what real occurrence is the combustion of the world
by Phaethon, a tradition ; or the submersion of the island
Atlantis; or the splitting of the continent Lyctonia into the
islands of the Mediterranean # l Although Sicily was to the
Greeks " the Threepointed Island f," from the earliest time
in which it is named by them, and Scylla and Charybdis
appear in the voyage of Ulysses, must we suppose that there
was a real tradition of its having been a part of Italy, sepa-
rated from it at Rhegium % by an earthquake ?

We seem, therefore, to be brought to the third supposi-
tion, that there is nothing historical in the flood ofDeucalion,
and that all the circumstances which we find in Greek authors
respecting it, previously to the time when they may have mix-
ed their own accounts with those of foreigners, are fictitious.
But fictions must have a determining cause, and those which
relate to physical events generally have this cause in physical
appearances, popularly interpreted. Thessaly, the scene of
Deucalion's flood, and Bceotia, to which some, though fainter,
traditions of a similar event may have been attached, were both
countries which, from their structure, were peculiarly liable to
inundations. We are so accustomed to associate ideas derived
from Scripture with the words Jlood, deluge, cataclysm, that we
transfer them to other ancient history, and suppose that they
imply events of equal magnitude. But any overflowing of a
river which swept away what was upon its banks, was to the
Greeks a xaTaxAua-juo'f. The floods of Morayshire, and many of
much inferior extent, would have been called so by them.
The physical structure of Thessaly rendered it, of all parts of
Greece, the most natural scene of an inundation which should
dislodge mankind from their customary abodes. The whole
drainage of the valley which is inclosed by Pelion, Ossa, and
Olympus, Pindus and Othrys, takes place through the single

* Orph. Argon. 1283 seq.

f At least if the 0^**/>j of Homer (Od. *', 106. ^', 127.) be the Tri-
nacria of later geography, which can hardly be doubted. See Uckert, I. i.
p.21.

% Strabo, i. p. 88. ed. Oxon.

30 The Rev. John Kenrick on the alleged

outlet of the Vale of Tempe*; and it was not necessary to
have the eye or the imagination of a geologist, in looking at
this singular chasm, to perceive its use, and revert to the time
when no such opening existed, and the waters of the Peneius,
the Enipeus and the Apidanus must have discharged them-
selves into a lake covering the greater part of Thessaly. The
well-known passage in Herodotus (vii. 129.) shows how early
such an idea had been formed. It was then a Xoyog that all
Thessaly had been once a lake, and that Neptune, i. e. an
earthquake, had opened the passage by which the lake was
drained. That there was any real tradition of a time prior
to the opening of Tempe, I do not believe, for the very
first glimmerings of Grecian history show us Thessaly peo-
pled by various tribes, whose seats were on the banks of the
rivers; but if men speculated upon the condition of things
which must have preceded the opening of the outlet, and put
their speculations into the form of a \6yo^ why might they
not also speculate on the consequence of a sudden stoppage
of the outlet, or of a fall of rain so copious and long continued
that the narrow passage of the Peneius could not afford it
vent? Such a speculation, turned into a Xoyos, the form
which ancient hypothesis generally assumed, would include
all that belongs to the flood of Deucalion, separated from
foreign admixtures. I have already mentioned that, as re-
lated by Apollodorus, the story appears to contain portions
of two distinct mythi. Deucalion was probably at first only
the patriarch of the Hellenic tribe ; but as they had their ori-
ginal seat in Thessaly, and affected to consider the commence-
ment of their own history as the commencement of civilization,
the flood of Thessaly and the person of Deucalion would na-
turally be connected togetherf.

Bceotia, like Thessaly, is exposed, from its physical struc-
ture, to suffer from inundations. Its principal river, the Ce-
phisus, terminates its course in the lake Copais, the waters of
which have no superficial outlet to the sea, and would soon
lay the whole country under water, were it not that they find

* See Hawkins in Walpole's Memoirs of Greece, vol. i. p. 528.

f Mr. Keightley in his Mythology, p. 268, derives Deucalion from fava
(whence favxng) to wet, and perhaps atAj the sea. But besides the difficulty
that ZtvKYx does not appear to mean wet, why should Deucalion, who rode
dry in his *«£*«£ and whose flood was one of rain water, be called by a
name which means dipped in the sea? What if AiVKn'Aiav and the cog-
nate form AiVKcthog (Heyne ad II. v . 307.) were derived from Asvs, the
old form of Z*yj, and Kuhia? The commencement of religion among the
Hellenes would naturally be ascribed to the patriarch of the race, and he
was not only reputed to have founded Dodona in Thesprotia and to have
sacrificed to Jupiter on his deliverance, but even to have founded altars to
the twelve great gods.— -Apollod. 1. 7. 2. Eudocia, p. 108. 127.

Greek Traditions of the Deluge. SI

a vent by a subterraneous passage in the cavernous limestone,
and discharge themselves into the Euripus at Larymna.
This subterraneous channel was liable to be stopped, especially
by earthquakes, which were frequent in Bceotia, and the con-
sequence was, an inundation of the country around the lake.
In the time of Alexander the Great, an engineer, Crates of
Chalcis, was employed to open the obstructed passage, and the
shafts which he sunk down upon it may still be traced along
its course*. In a report addressed to Alexander, preserved
by Strabo, he says that many districts had already become
dry, and the sites of ancient towns had reappeared. Accord-
ing to some, Eleusis and Athens had stood here in the time
of Cecrops, who was king of Bceotia, then called Ogygia.
Pausanias again (ix. 38.) relates that Hercules had stopped
the subterraneous passage, in order to flood the fields of the
Orchomenians. The singular condition of this lake, and the
variations to which it was subject in winter and summer, to
say nothing of extraordinary rains and accidental stoppages
of the outlet, invited the fancy to frame wonderful tales re-
specting it, and we may surely account for the flood of Ogyges
without having recourse to that of Noah. The wonderful
coincidence in time, which made Cuvier (p. 85.) conclude
that the former one must have been derived from the latter,
really depends on a date arbitrarily fixed by the chronolo-

serst-.

I will mention one other opinion^, which connects the
stories of destruction by water and fire together, and supposes
them to have originated in the observation, that at the dif-
ferent seasons of the year, more strongly discriminated in
southern climates than in our own, the principles of moisture
and heat alternately predominate, whence arose the notion
that the annus magnus, which comprehended a vast cycle of
celestial phenomena and terrestrial changes, included both
a xuroix.\v<rp6$ and an ex7r6pco<Ti$ \\ . This may have been the
origin of the Egyptian doctrine and of that of Heraclitus and
the Stoics; it may have had a share in producing the story
of Phaethon; but the deluge and the conflagration do not ap-
pear to me to have had any connexion with each other in the
popular conceptions of the Greeks, which alone it has been
my object to examine.

The result of this examination will not, I hope, appear al-
together unimportant. It is not difficult to foresee that the

* Walpole, i. p. 303. seq.

t Cuvier quotes Varro as placing the deluge of Ogyges 400 years before
Inachus; but it does not appear from the passage in Censorinus (21.) that
Varro mentioned the name of Ogyges.

I Bohlen, Altes Indien. i. p. 21S). || Censorinus 18.

32 On the alleged Greek Traditions of the Deluge.

time is approaching, when geologists will no longer refer all
marks of the superficial action of violent currents of water on
the earth, subsequent to the consolidation of its newest strata,
to one flood, limited in its time and strictly defined in its cir-
cumstances, as the Mosaic deluge is ; but will be compelled
to acknowledge that their science points to prolonged, repeated
and multiform operations of diluvial currents*. The popular
view of this subject derives a strong support from the belief
that other nations have a real tradition of the Mosaic deluge,
and that something like a chronological coincidence between
them can be established. If this opinion has been shown to
be unfounded, scientific inquiry into the phenomena of dilu-
vial agency on the earths surface will not be embarrassed by
the necessity of making its results conform to those of another
branch of knowledge.

I will only observe in conclusion, that the Mosaic account
of the Deluge appears to me to bear many of those marks of a
tradition of high antiquity, which we have sought in vain in
the Greek legends of Deucalion. It is found in the book which
the Jews have always regarded as the most ancient of their
sacred writings, and it exhibits traces, as critics of the first
name assure us, of being itself a document yet older than the
book in which it has been incorporated. It does not corre-
spond with the traditions or speculations of the Egyptians or
the Phoenicians, but in a remarkable manner with those of the
people of Mesopotamia and Chaldaea, countries with which
the Jews were connected by the origin of their nation. Had
they framed it for themselves, it would have been natural for
them to refer it to their own country, to have made Noah
build his ark in the forests of Lebanon, and the ark rest on
the top of Hermon or of Carmel. Instead of this, everything is
referred to the valley of the Euphrates and the Tigris. The
cypress of which the ark was built was the only wood fit for
ship-building which this region afforded f; the bitumen with
which it was covered was the product of its asphaltic springs J ;
the mountain on which it rested is that from the vicinity of
which the Tigris and Euphrates rise, and which looks down

* [See Prof. Sedgwick's Anniversary Address to the Geological Society in
1831, Phil. Mag. and Annals, N.S. vol. ix. p. 313; and also Mr. Greenough's
late Address to the same body, in our present Number. — Edit.]

t The testimony of Arrian, ix. 19., that the cypress was the only wood
fit for ship-building of which there was any considerable quantity in Assyria,
with the correspondence of the consonants in 1£)J and Kwupaoos, is,
I think, decisive in favour of the opinion of Bochart and Celsius that the

fopher wood is the cypress. [See Mr. Beke's paper on this subject, in
,ond. and Edinb. Phil. Mag. vol. iii. p. 103.— Edit.]
t Herod, i. 179. [See Mr. Beke's Remarks on Mr. Carter's paper, in
our Number for Apriflast, or vol. iv. p. 280.— Edit.]

Remarks on the Atomic Constitution of Elastic Fluids. S3

over the countries through which they flow; the plain of
Shinar is the scene in which the history of mankind recom-
mences when the Deluge is over. Unless we could suppose
the Pentateuch to have been written after the captivity, and
the Jews to have begun their history with the borrowed tra-
ditions of their oppressors, we must admit that these things
were subjects of belief in the family of Abraham from the
time when he left his original abode in Ur of the Chaldees*.

IV. Remarks on the Atomic Constitution of Elastic Fluids. By
William Charles Henry, M.D., F.li.S.f

T^HE following remarks, suggested by that portion of Dr.
■f- Prout's Bridgewater Treatise which is devoted to the
most comprehensive generalizations of chemical philosophy,
are proposed with considerable hesitation, from their not ac-
cording with the views of that profound writer. But it must
also be borne in mind, that the theory of atomic combina-
tion adopted by Dr. Prout differs itself, most materially, from
that originally framed by the author of the atomic philosophy,
and still held by him, as well as by the majority of British che-
mists. These differences, as far as they respect first principles,
may be comprehended in the two following propositions :

1st, That equal volumes of all gaseous bodies contain,
under the same temperature and pressure, the same number
of self- repulsive molecules.

2nd, " That the self-repulsive molecule, as it exists in the
gaseous form, does not represent the ultimate molecule, but is
composed of many of them.',

1st, The idea that the particles of all gaseous fluids are
placed at the same distances from one another, and conse-
quently that a given space contains in all the same number of
molecules, seems to have occurred about the same time to
MM. Ampere and Avogadro. It was published by the former,
so early as the year 18 14-, in a letter addressed to Count Ber-
thollet, but merely as the most probable hypothesis of the
constitution of elastic matter J. It was subsequently revived
by Dumas, and has been recently maintained and illustrated
by his pupil M. Gaudin§. Dr. Prout had arrived at the same

• [Our correspondent Mr. Beke, in the Appendix to his recently pub-
lished work, entitled Origbws Biblicce, has shown reasons for the belief that
the Flood, though universal with respect to mankind, was merely local
with respect to the globe itself; a view of the subject which, if fully sub-
stantiated, would tend to relieve it from much of the difficulty in which it
is at present involved. — Edit.]

f Communicated by the Author. \ Ann. de Chimie, torn. xc. p. 47.

§ Ann. de Chimie et de Phys., torn. Hi. p. 113.

Third Series. Vol. 5. No. 25. July 1834. F

34 Dr. W. C. Henry's Reniarfo on the

conception without being aware that it had been previously
entertained by others. These distinguished chemists do not,
however, concur with Ampere in regarding it in the light
merely of an hypothesis, but conceive that it is strictly deriv-
able from the well-known law of Mariotte, and from the si-
milar relations of gaseous bodies to heat. They have there-
fore made the first of the above propositions the basis of their
peculiar views on atomic combination, and have certainly suc-
ceeded in proving that the second and more important pro-
position flows from the first in direct logical sequence. It is
therefore necessary to examine, with peculiar care, the grounds
upon which the major term is supposed to rest.

The law of Mariotte, that in all elastic fluids the volumes
vary inversely as the compressing forces, will be found to
warrant no inference as to the number of atoms existing in
a given volume of the different gases. It is derived from
the law of variation observed by the repulsive forces which
actuate the molecules of elastic fluids, not from the nume-
rical aggregation of atoms in space. Newton has demon-
strated (Princ., Lib. II. Pr. xxiii.) " that particles flying
from each other with forces that are reciprocally propor-
tional to the distances of their centres, compose an elastic
fluid whose density is as the compression," Now this is the
law of Mariotte, which is hence independent of all elements
other than repulsive forces, varying inversely as the atomic
distances or diameters. Whatever be the comparative di-
stances of the particles of two gases A and B under any given
pressure, the same for both, there must, in conformity with
the law of Newton, be an equal diminution of their bulk on
equal increments of pressure. For illustration, let us suppose
the atoms of A to be at double the distance that exists be-
tween the atoms of B under the pressure of one atmosphere.
Let the two gases be subjected to the pressure of an additional
atmosphere. Then, since the molecular forces in both vary
according to the same law, both gases will be alike reduced to
half their original volume. But the number of atoms of B is
eight times that of A. Hence it is manifest that the law of
Mariotte has no reference whatever to the numerical relations
of atoms in the different gases.

2nd, The argument founded on the equal expansion of the
gases by heat, does not appear to be possessed of greater co-
gency. In the first place, it is consistent with the best recent
experiments, as will be shown hereafter, that equal increments
of absolute heat do not produce equal dilatations of volume in
the different gases, and that this relation can only be correctly
predicated of equal increments of temperature. Now there seems

Atomic Constitution of Elastic Fluids. 35

more reason to anticipate the existence of such a relation be-
tween the number of molecules and the absolute or specific
heat, than between that number and the heat of temperature.
Upon this principle, since unequal increments of absolute heat
are required to effect equal expansions, we should conclude
that the numbers of atoms are also unequal.

That equal increments of temperatures should affect all
elastic fluids in the same degree, is a manifest consequence of
the constitution of such fluids. The unequal expansibility of
bodies in the solid and liquid states is to be ascribed to the
interference of the attractive forces which maintain those con-
ditions of matter, and which counteract, with energies vary-
ing in different bodies and at different distances, the repulsive
agency of heat. But the molecules of elastic fluids are se-
parated to such a distance from one another that their mutual
attractions become insensible *. They are therefore sub-
jected to the undisturbed influence of repulsive forces. Ac-
cording to the theory of Laplace, caloric constitutes the sole
agent of repulsion; and equal increments of temperature, being
identical with equal increments of elasticity, are necessarily
followed by equal expansions. " Sous une pression constante la
densite d'un gaz etant, comme on Pa vu, reciproque a cette
fonction de la temperature, son volume est proportionnel a cette
fonction...la temperature est alors representee par ce volume,
et ses variations sont representees par les variations du volume
d'un gaz soumis a une pression constante."

It cannot be requisite to pursue this argument further, since
it has been shown by Laplace, that both the law of Mariotte,
and that of equal expansion discovered by Dalton and Gay-
Lussac, are mathematically derivable from the following sup-
positions:— that the molecules of gases are at such a distance
that their mutual attractions are insensible; — that these mole-
cules retain caloric by a principle of attraction ; — that their
mutual repulsion is due to the repulsion of the molecules of
caloric; — and, finally, that this repulsion is only sensible at
imperceptible distances. If these suppositions be conceded,
the laws of Mariotte and of Dalton are susceptible of rigid
demonstration, and are moreover applicable to all elastic fluids,
whatever be the nature or the number of their molecules.

There is a third argument noticed by Dr. Prout, to which
M. Dumas attaches much weight, in support of the doctrine
of equality of atoms in a given volume. It is founded on the
recent experiments of MM. Delarive and Marcet, which show
that all the gases, in equal volumes, have the same capacity

* Mccanique Celeste, livre xii. ch. i. torn. v. p. 89-91.
F2

36 Dr. W. C. Henry's Remarks on the

for heat. Now it had long ago been suggested by Dr. Dalton
as the most probable view of the relations of elastic fluids to
heat, that " the quantity of heat belonging to the ultimate
particles of all elastic fluids must be the same under the same
pressure and temperature." Dulong and Petit have since
inferred from their experiments, that the specific heats of se-
veral simple bodies in the solid state, when multiplied by their
atomic weights, give a constant quantity as their product*.
This relation has more recently been shown by M. Neumann
to extend to several compound mineral substances f. Admit-
ting, then, the equality of the specific heats of the gases when
equal volumes are compared, and also that their ultimate
atoms possess the same amount of heat, M. Dumas' s con-
clusion, that equal volumes must contain the same number of
ultimate atoms, is perfectly legitimate. But one of the ele-
ments of his calculation is erroneous:}:. M. Dulong, in his ela-
borate memoir on specific heat§, has subsequently established
the impossibility of obtaining, by the experimental process of
Delarive and Marcet, even an approximative measure of the
specific heats of the different gases, and has shown that the
earlier results of Delaroche and Berard are still those most
deserving of confidence. His own experiments, founded on
the relations between the specific heats of gases and their
powers of propagating sound, concur with those of Berard in
indicating considerable differences in the specific heats of the
gases, whether equal weights or bulks are made the objects of
comparison. Substituting, then, these results for those of
Delarive, we obtain, by the process of reasoning adopted
by Dumas, the opposite conclusion,— that equal volumes of
the different gases compared, contain unequal numbers of
atoms || .

* Ann. de Chimie et de Phys. torn. x. p. 405.

t Poggendorff's Annalent vol. xxiii. p. 32.

X Traite de Chimie appl. aux Arts, torn. i. p. 41.

§ Ann. de Chimie et de Phys. torn. xli. p. 113.

|| This argument is not urged as possessing more than a negative force.
The specific heats of the gases are not yet determined with certainty; and
it is even doubtful whether, if obtained, they would faithfully represent
the absolute heats, — a supposition manifestly involved in the principle of
calculation, that the specific heats are equal to the absolute heat of one
atom multiplied by the number of atoms in a given volume. It cannot,
moreover, be denied, that the specific heats of hydrogen, oxygen and nitro-
gen, obtained by Delaroche, are so nearly the same in equal volumes, that,
allowing for probable errors, they may safely be regarded as identical.
Hence, upon the principle of Dulong and Petit, those three gases must
contain the same number of atoms, and the weight of the atom of oxy-
gen must be represented by 16 (the number adopted by Berzelius) instead
of 8.

Atomic Constitution of Elastic Fluids. 37

It has been the object of the foregoing remarks to prove
that there does not exist, in the principles of general physics,
any foundation for the new doctrine of Dr. Prout and M. Du-
mas, " that a given volume contains the same number of ulti-
mate atoms in all the different gases*." These principles,
however, with the exception of the relations of specific heats,
though they do not furnish any support to such a doctrine,
must be acknowledged to involve nothing that is contradic-
tory to it. It must be considered, therefore, simply as an
hypothesis, the value of which is to be estimated by its appli-
cability to chemical phenomena. When tried by this test, it
will be found wholly untenable, unless it be supported by a
second and yet more improbable hypothesis, " the divisibility
of the atom." Indeed, the single example of muriatic acid
gas is sufficient to demonstrate its unsoundness. A volume
of this gas is constituted of half a volume of hydrogen and
half a volume of chlorine. The number of atoms in a volume
of hydrogen is therefore double that in the same volume of
muriatic acid gas. Nitrous gas, in like manner, must contain
half the number of atoms that are contained in an equal volume
of azote. The same is true of ammoniacal gas, of hydriodic
acid gas, of hydrocyanic and chlorocyanic acid vapours, and
of the vapour of sulphuret of carbon, when compared with an
equal volume of one of their constituents. It may, then, be
confidently asserted, that chemical phsenomena, at least as
they are now generally interpreted, are inconsistent with the
notion of an equality of atoms in all gases, compound and
simple.

It is solely upon this supposed numerical equality of atoms
that Dr. Prout's second proposition is founded. Now if it has
been shown that such equality is not derivable from physical
principles, and is also inconsistent with known chemical facts,
that proposition can be no longer maintained, except as an in-
dependent hypothesis; and we are compelled, by the rules of
philosophizing, to recur to the simple and beautiful concep-
tion of the indivisibility of the atom, taught by the illustrious
author of the atomic system. Several considerations may,
moreover, be urged in favour of the doctrine of Dalton, that
the mutually repulsive molecules of elastic fluids are identical

* It is not asserted that there do not exist any two gases which contain
in the same volume the same number of ultimate atoms. On the contrary,
most of the simple gases and vapours, and some of the compound gases,
are generally believed to be thus similarly constituted. We object only to
the raising what is true in certain individual examples into a general and
necessary proposition.

38 Remarks on the Atomic Constitution of Elastic Fluids.

with the ultimate chemical atoms. We have already had oc-
casion to refer to the postulates employed by Laplace as the
basis of his profound mathematical inquiries into the consti-
tution of elastic fluids. Now if heat be combined with the
particles of matter by a principle of attraction or affinity (as
supposed by Laplace), it is impossible to conceive such affinity
to be exercised by aggregates of atoms, and yet not to be the
attribute of the single atoms, of which such aggregates are
composed. And if the ultimate atoms be endowed with an
affinity for caloric, no reason can be assigned why union
should not take place between caloric and each ultimate atom
singly; nor, the molecules of heat being self-repulsive, why
the ultimate atoms after such union should not become mu-
tually repulsive. The contrary hypothesis of Dr. Prout in-
volves the anomaly of supposing heat to have a combining
affinity for two or more atoms, while it is destitute of such af-
finity for single atoms ; and also that of supposing two atoms
to have relations towards two atoms, or three towards three,
which do not obtain between single atoms.

It is furthermore apparent, that the question respecting
the mode of union between heat and the molecules of bodies,
is not limited to the constitution of elastic fluids, but must
equally comprehend the conditions of liquid and of solid.
Now the relations of several simple bodies to heat, established
by the experiments of Dulong and Petit, point unequivocally
to the chemical atoms, as determining the measure of specific
heat. In the thirteen simple substances which were the sub-
jects of experiment, they found that the product of the spe-
cific heats into the atomic weights was invariably a constant
quantity, and consequently that the ultimate atoms contained
precisely the same quantity of caloric. These results have
been since confirmed by various German experimenters*, and
can only be reconciled with the doctrine of the combination
of heat with the ultimate chemical atom.

In recapitulation, it has been shown,

1st, That the law of Mariotte, and that of the equal expan-
sibility of the different gases, are mathematically derived from
elements altogether foreign to the numerical relations of their
ultimate molecules ; and that no corollary is contained in those
laws, determining equality of atoms in a given volume of the
different elastic fluids.

* See Mr. Johnston's excellent and comprehensive Report on Chemistry,
in the Rejiort of the First and Second Meetings of the British Association for
the Advancement of Science, p. 418.

Mr. Pratt's Demonstration of the Parallelogram of Forces. 39

2nd, That the most trustworthy experiments on the spe-
cific heats of the gases, combined with the law of Dalton,
Dulong, and Neumann, lead to an opposite inference.

3rd, That several examples of chemical combination are
inconsistent with the doctrine of numerical equalityof atoms
in equal spaces of the different gases.

4th, That the original hypothesis of Dalton, which contem-
plates the self-repulsive gaseous molecule as identical with the
ultimate chemical atom, has in its favour the greatest amount
of probabilities.

Manchester, June 7, 1834.

V. A Demonstration of the Parallelogram of Forces. By
J. H. Pratt, Esq.*

T ET P Q be two forces acting on a point, their directions
-*-i including an angle a ; and let R be their resultant, acting
in the same plane with P and Q, and making an angle 6
with P.

Suppose P to be equivalent to two forces Pj P2, acting in
direction of 11, and perpendicular to this direction ; and let Q
be equivalent to Qx Q2, acting similarly;

To find the relation between Fx and P, we observe that
since the law of resolution must be independent of the magni-
tudes of P and Pj so long as their ratio is the same, Pl must
be of the form Px = P./(0),

where/* (0) is to be found.

Now, when 0 = 0X — , tt1 rjcft 2ttj ...

P1 = P,0,-P, Q, Px

and from these we see that if n be any integer

/(*•?) =^(«-i) (2-)

When 0 has any value not comprised in the above formula,
the only conditions to be satisfied byf(Q) are, that the sum
of the resolved parts of Pj and P2 in the direction of P shall
equal P, and perpendicular to this equal 0 :

.-. P-P1/(») + Pg/(-|--»),

* Communicated by the Author.

40

and

or

Mr. Connel's Analysis of Levyne.
0=P1/(y-«)-P2/(9)

1=firr+f(JZtj<

(3.)

The second equation is identical.

Now any form of#/(0) which fully satisfies the equations
(2.) (3.) must satisfy the conditions of the problem; and there

can be but one form which does satisfy the equations, for -p1-

must have a definite numerical value for every value of 5, and
•'• f (0) can contain no arbitrary quantities.

Now / (0) = cos 0

fully satisfies equations (2.) (3.), .\ this is the only, and .\ the
true, value off(8).

Hence by equations (1.)

R = P cos0 + Q cos (a — 0)

0 = Psin0-Qsin (*-0) (4.)

adding the squares

R* = P3 + Q2 + 2PQcos * (5.)

Take AB, AC proportional to P and
Q ; draw BD parallel to AC, cutting
AD in D ; and join DC :

BD =

sin

AB

g.AB

sin (a — 0)
by (4.) = AC.

.*. AD is in the direction of the dia-
gonal.

Also AD2= AB2 + AC2 + 2.AB.
AC . cos a.

Comparing this with equation (5.),
we see that AD represents R in mag-
nitude as well as direction.
Caius College, Dec. 6, 1833.

J. H. Pratt.

VI. Analysis of Levyne. By ArthurConnel,^^. F.R.S.Ed.*

A FEW years ago Sir David Brewster described this mi-
■**■ neral as a new species, founding his discrimination of it on
an examination of its optical properties by himself, and on a
determination of its crystallographical characters by Mr.' Hai-

* Communicated by the Author.

Mr. Connel's Analysis 0/" Levyne. 41

dinger*. At the same time he transmitted a small quantity of
the mineral to Berzelius for chemical examination ; and soon
afterwards, in a paper inserted in the Transactions of the Royal
Swedish Academy for 1824f, Berzelius gave the following as
the constituents of the mineral :

Silica 4.8-00

Alumina 20*00

Lime 8*35

Magnesia 0*4

Potash 0*41

Soda 2-75

Water 19*30

99-21
Berzelius accompanied his analysis with a statement that
he considered the mineral to be merely a chabasite. From a
subsequent explanation of Sir David Brewster J, however, there
is every reason to believe that Berzelius had not distinguished
the levyne from some chabasite which accompanied it in the
same specimen, and that in reality a mixture of both minerals
had been subjected to analysis, a mistake which is not very
surprising, considering that levyne was at that time entirely a
new mineral, and its aspect consequently little known.

Had not a reasonable doubt been thus thrown on the iden-
tity of the subject of Berzelius' s analysis, any further exami-
nation of the chemical nature of levyne would have been a very
superfluous task; but under the circumstances, it became
very desirable that a new analysis should be executed of un-
doubted crystals of this mineral.

The specimens examined were partly furnished me by the
kindness of my friend Mr. Robert Allan, and partly in my
own possession. They were all of Irish locality §. The cry-
stalline form was quite distinct, and exactly that described by
Mr. Haidinger. I regret that it was not in my power to ope-
rate on larger quantities of materials than those employed.

To determine the specific gravity of the mineral, the largest
portions of the crystals separated were selected, the quantity
so selected amounting to only 9*3 grains. Their specific
gravity was found to be 2*198 at 55° Fahr. The mineral
by ignition gave off water, the proportion of which in a mean
of two trials, giving almost exactly the same result, amounted
to 19*51 per cent.

To determine the proportion of the other constituents,
10*28 grains of the crystals in impalpable powder were treated

* Edinburgh Journal of Science, vol. ii. p. 332. f p. 356.

± Edinburgh Journal of Science, vol. iv. p. 316.

§ In addition to the other known localities of this mineral, I may
mention that I have found specimens of it in the island of Skye.
Third Series. Vol. 5, No. 25. July 1 834 . G

42 Mr. ConnePs Analysis qfLevyne.

with muriatic acid. Speedy gelatin ization took place with
rise of temperature. Silica was separated in the usual man-
ner, and, after ignition, weighed 4*7 1 grains. From the resi-
dual liquid ammonia threw down alumina, which when ignited
weighed 2*4 grains. By dissolving it in muriatic acid, and by
the subsequent action of caustic potash, and other necessary
steps, there were separated from it *03 of silica, *03 of oxide of
iron, and *03 of red oxide of manganese, equivalent to *027 of
protoxide, leaving 2*31 for the amount of the alumina. To
the liquid which had been precipitated by ammonia, oxalate
of ammonia was added, its action being aided by heat. The
precipitate obtained yielded by calcination under the usual
precautions 1*84 of carbonate of lime, from which, however,
•05 of oxide of iron were separated by solution in diluted mu-
riatic acid, and the agency of hydrosulphuret of ammonia,
leaving 1*785 of carbonate of lime, equivalent to 1-004 of lime.
The remaining liquid was evaporated to dryness, and the am-
moniacal salt driven off" by heat, when a residue of *61 re-
mained, which, when dissolved in water, left *02 of silica, with
a trace of lime and magnesia. The solution gave cubical cry-
stals by spontaneous evaporation; and by the agency of chlo-
ride of platinum and of alcohol, these crystals were found to
consist of *20 chloride of potassium, equivalent to *13 potash,
and '39 chloride of sodium, equivalent to *16 soda.

We have thus in 10*28 grains of the mineral, exclusive of

water, Silica (4*71 -r-*03 + '02) 4*76

Alumina 2*31

Lime 1*

Soda -16

Potash -13

Oxide of iron (-03 + '05) -08

. — manganese '02

8-46
And in 100 parts:

Silica 46*30 contains oxygen ... 24 05 ... 7

Alumina 22*47 ... 10*49 ... 3

Lime 9*72 2*73

Soda 1*55 -39

Potash 1*26 *21

3*33 ... 1

Oxide of iron #77

manganese *19.

Water 19*51 17*23 ... 5

TovrT*

* In operating upon small quantities, any accidental loss or excess of
course becomes magnified when reduced to 100 parts. The excess on
the analysis of 10*28, taking the proper proportion of water into account,
was only '18.

Mr. ConnePs Analysis of Levyne. 43

For the purpose of comparing this analysis with the con-
stitution of chabasite, we may take the following examples of
the analysis of the ordinary lime chabasites.

Silica 50-65 ... 48*38 ... 50*14

Alumina 17*90 ... 19*28 ... 17*48

Lime 9*73 ... 8*70 ... 8*47

Potash 1*70 ... 2*50 ... 2*58

Water 1950 ... 20*00 ... 20*83

99*48* 98*86 f 99*50$

From this comparison it undoubtedly appears that the mi-
neral under examination possesses, chemically speaking, con-
siderable analogy with chabasite, but still the differences seem
to be such as prepare us for admitting it as a distinct species,
provided that its crystallographical and optical properties lead
us to that conclusion.

Had the form of the crystal of levyne been found to be the
same as that of chabasite, we might have admitted that the
differences of the composition of the two minerals arose from
accidental impurities, examples of such discrepancies some-
times occurring in regard to different individuals of the same
species, as in the different analyses of barytic harmotome. But
according to the determination of Mr. Haidinger, the crystal-
lographical differences between levyne and chabasite are of a
very marked description, the fundamental form of the former
mineral being a rhomb of 79° 29', whilst that of the latter is a
rhomb of 94° 46'. A like discrepancy occurs in regard to the
optical properties as determined by Sir David Brewster, levyne
conforming to the general law of rhombohedral crystals in
having one axis of double refraction, whilst the optical struc-
ture of chabasite is very anomalous.

It would appear, therefore, that we cannot hold chabasite
and levyne to be the same mineral without disregarding cry-
stallographical and optical differences of a marked description ;
and on the other hand, there evidently appear to be sufficient
chemical differences to entitle us to give effect to the distinc-
tions of external and optical characters, the difference of com-
position being at least as great as that between some other
well established species, as, for instance, between stilbite and

* From Gustavsberg, analysed by Berzelius. — Edinb. Phil. Journal,
vol. vii. p. 10.

t From Fassa, analysed by Arfwedson. — Ibid.

X From Renfrewshire, analysed by myself. — New Edinb. Phil. Journal,
▼ol. vi. p. 26C.

G2

44 The Rev. W. D. Conybeare on the probable

heulandite. The formula which seems best to express the
constitution of levyne is

N. >S + 3AS3 + 5 Aq, which differs from that usually adopted
P J for chabasite in containing one atom less of silica, and
one atom less of water.

VII. On the probable future Extension of the Coal-fields at
present worked in England. By the Rev, W. D. Cony-
beare, M.A.9 F.R.S., §c.

[Continued from vol. iv. p. 348.]

I" HAVE already pursued my proposed examination through
*■ a considerable proportion of the coal-fields of our central
district (namely, the eastern division, including the fields of
Ashby-de-la-Zouch and Warwickshire, and the smaller patches
near Ashborne on the south of the great Derbyshire chain).
I consider the general result to be, that throughout this cen-
tral district the whole stratification is so extremely disturbed
and undulating that we are scarcely able to form any antici-
pations as to the probable prolongation of the beds which
can be at all relied upon ; but that in very few instances the
boundaries of the fields have as yet been ascertained with any-
thing like scientific exactness ; that a survey undertaken ex-
pressly with a view to this inquiry is undoubtedly very de-
sirable ; and that it is little to the credit of a nation like ours,
so peculiarly dependent on this branch of her mineral re-
sources, that we thus continue contentedly to acquiesce in a
state of ignorance so easily removed. We here see a strong
instance of our want of a regular school of mining, such as is
possessed by many other countries.

In continuing my own imperfect hints with a view to such
ulterior inquiries, I shall first complete the central districts by
noticing the Dudley coal-field.

Dudley Field. — The boundaries of this field can hardly yet
be considered as accurately ascertained. The anticlinal ridge
of transition limestone of Dudley throws up the beds which crop
out all round it; and as on the eastern edge of the field near Wal-
sall, the same transition limestone again emerges, we may con-
sider the coal-measures around Bilston as lying in a trough be-
tween these points. I do not find any account of the exact limits
of this trough on the N.W. border from the Dudley lime-
stone range to Cannock, at the northern apex, or on the N.E.
from Cannock to Walsall ; but I rather believe that the beds

future Extension of the English Coal-fields. 4-5

crop out in these directions ; so that we cannot in these quar-
ters look for any probable extension. Not so, however, with
regard to that portion of the coal-field which, ranging beneath
the overlying basalt of the Rowley Hills, extends to the west
and south-west of Dudley: here from Wolverhampton to
Stourbridge the beds dip beneath the new red sandstone in a
westerly direction, and pursuing that course about 10 miles,
we see the coal-measures again emerging from beneath this
investiture around Over Arley in Shropshire. The western bor-
der of this Dudley field, and the eastern border of correspond-
ing Shropshire fields, ought to be carefully examined, as it seems
very 'probable that the strata may here extend continuously
within workable depth.

Indications of Coal at the foot of the Bromsgrove Lickey. —

These are so exceedingly shattered and disturbed as to
afford very little prospect of leading into any valuable working
districts.

Coal-fields of Northern Staffordshire. — These, which follow
in order the patches near Ashborne, mentioned in my last,
consist of two detached fields, lying against the S.W. corner
of the great Derbyshire Penine chain : 1. the field of Cheadle,
ranging along the river Churnot, described by Farey as a
detached basin reposing on the millstone grit; and, 2. the
Pottery coal-field of Newcastle-under-Line, occupying a tri-
angular area extending to Congleton on the north. From the
eastern and western sides the beds dip towards the centre ;
but we are not informed in what manner they are disposed
along the southern base of the triangle by Newcastle : as they
are here overlaid by the new red sandstone, their prolonga-
tions may very possibly be traced to some distance beneath it.
This portion requires reexamination.

Great Manchester Coalfield. — This field, reposing against
the western slope of the Penine chain, ranges from Maccles-
field to the east of Manchester, and then curving to the W.
and S. W., extends nearly to Liverpool. The public is not yet
in possession of any scientific description of this most im-
portant field ; but recent announcements promise that this
desideratum will be shortly supplied. As this coal-field ap-
proaches near to the aestuary of the Mersey, where it dips
beneath the new red sandstone, and as along the western
border of the almost contiguous aestuary of the Dee the coal-
measures again emerge, skirting the whole Flintshire coast of
that aestuary, I am persuaded that they will hereafter be
found to extend continuously, and within workable depth be-
tween these points. . The whole peninsula of Wirral may be
expected thus to afford a productive coalfield : this is probably

46 Mr. J. Hogg and Sig. Tenore on the comparative Influence

the most important accession which we can look for of the fields
already worked.

North Welsh and Shropshire Coalfields. — The memoirs of
Mr. Murchison promise to afford important additional in-
formation concerning these districts. I have already in this
communication indicated their probable eastern extension, viz.
of the Flintshire coal-field to join that of Lancashire; and of
the Shropshire fields, near Bridgenorth and Over Arley, to
join that of Dudley. With regard to the north-western coal-
fields, as we approach the Cumbrian mountains, or lake di-
strict, that of Ingleton on the south of the carboniferous
limestone encircling this group appears to constitute a small
basin reposing on millstone grit, the shattered tract extending
hence eastwards to Giggleswick; and the immense faults
which traverse this district have been admirably described by
Mr. Phillips (Geological Transactions, New Series, vol. ii.).

On the northern border of the Cumbrian mountains, from
Whitehaven on the western coast, to Ravensworth, where the
Cumbrian and Penine chains inosculate, on the east, a regular
zone of coal-measures appears to succeed the carboniferous
limestone, and though the principal workings are at the two
extremities, indications have been found at various points be-
tween these fields ; hence we may hereafter look for a con-
siderable extension beneath the new red sandstone of the Vale
of Eden.

In my next communication I propose to conclude these re-
marks by a similar notice of the south-western coal district.
Your old Correspondent,

W. D. CoNYBEARE.

VIII. On the Influence of the Climate of Naples upon the
Periods of Vegetation as compared with that of some other
Places in Europe. By John Hogg, Esq., M.A., F.L.S.
F.C.P.S., %c.

[Continued from vol. iv. page 279.]

II. Erondescence.

THE time of the unfolding of the leaf-buds of trees, which
Linnaeus has called Frondescentia, and which the French
botanists have distinguished by the word Bourgeo?inement, pre-
sents the same variations that have been observed in the ger-
mination of seeds : since the diversity of the climates and of
the seasons exerts likewise a great influence on this period of
vegetation.

In the same places of his Philosophia Botanica before men-

of the Climate of Naples upon the Periods of Vegetation. 47

tioned, Linnaeus relates some observations concerning the
frondescence of trees in the vicinity of Upsal, in which he there
says that the Elder unfolds its buds in the first days of
March ; the Indian Chestnut, the Pear, the Spindle Tree, open
in the beginning of April; the Elm, the Cherry Tree, the
Filbert, in the middle of March ; the Birch, the Beech, the
Lime, and the Oak, in the first days of May.

About Naples, the Elder developes its leaves in the first
15 days of January; the Elm and the Filbert open their buds
in the beginning of February ; the Spindle Tree, and the
Indian Chestnut in the first week in March ; the Birch, the
Beech, the Lime, about the 15th of the same month; the
Hazel and the Oak in the beginning of April.

In general, we may therefore assert, that in the environs of
Naples the expansion of the leaf is earlier by one month and
a half than that of the same plants in the North of Europe.

Being desirous to compare this time of vegetation of the
trees near Naples with that of the trees which grow in the
neighbourhood of Paris, I have consulted the observations
made by Dr. Chavassieux d'Audibert in his Exposition des
Temperatures, and I have found that this period of vegetation
gives, between the two countries, the difference of one month.

In fact, M. d'Audibert fixes the middle of February for
the appearance of the leaves of the Elder; March, for that of
the Osier, of the Elm, of the Almond, and of the Chestnut;
April, for that of the Birch, of the Hazel, and of the Bramble;
May, for that of the Oak and Mulberry ; whilst around Naples,
as it has been before shown, these trees put forth their leaves
one month sooner.

[Now, in England, we learn from the Naturalist's Calendar,
kept from 1768 to 1793, that at Selborne in Hampshire, Mr.
White has recorded March 13. as the earliest, and March
20. as the latest date, in which he noticed the expansion of
the leaves of the Elder ; but Mr. Markwick observed January
24. and April 22. as the earliest and latest days for the same
occurrence at Catsfield near Battle in Sussex. In the same
Calendar, it is also stated that the leafing of the Elm was seen
on April 3. by White, and on April 2. and May 19. (earliest
and latest) by Markwick. That of the Beech, according to
White, occurred on April 10. the earliest, and on May 8. the
latest, whilst according to Markwick April 24. and May 25.
are the soonest and latest days. And for that of the Mul-
berry with the former, May 27. and June 13., but with the
latter, May 20. and June 11. are the earliest and the latest
dates given.

By calculating the mean day between the earliest and latest

48 Mr. J. Hogg and Sig. Tenore on the comparative Influence

of these observations, we have March 16. (White at Selborne)
and March 8. (Markwick at Catsfield), for the frondescence
of the Elder. April 3. (W.) and April 25. (M.) for that of
the Elm. April 23. (W.) and May 9. (M.) for that of the
Beech, and June 4. (W.) and May 31. (M.) for that of the
Mulberry.

Again, we find from the table of the " Indications of
Spring," published in vol. ii. p. 128, of Loudon's Magazine
of Natural History, which contains the result of more than
60 years' (from 1735 to 1 800) observation by Mr. Marshham,
and Lord Suffield, at Stratton Strawless in Norfolk, that the
leafing of some of the before-named trees took place there
according to the following dates.

Leafing.

Earliest.

Latest.

Greatest difference
observed in

Medium Time.

Elm

Birch....
Beech....
Lime ....

Oak

Chestnut

1779- Mar. 4
1750. Feb. 21
1779- April 5
1794- Mar. 19
1750. Mar. 31
1794. Mar. 28

1784. May 6
1771. May 4*
1771. May 10
1756. May 7
1799. May 20
1770. May 12

47 years— 63 days

52 years — 72 days.

53 years— 35 days.
43 years — 49 days.

54 years — 50 days.
36 years — 45 days.

1773. April 6
1745. March 29
1785. April 23
1796. April 13
1757. April 26
1776- April 21

Hence we may say, from the data before stated, that at
Upsal the Elder unfolds its leaves about one week, the Elm
one month, sooner; but the Beech from three days to a week,
the Oak seven or ten days, the Lime two to three weeks, and
the Birch nearly five weeks later than the same usually do in
England. That at Naples, the Elm is earlier by about ten
weeks, the Elder nine weeks, the Beech seven weeks, the Lime
four weeks, the Oak three weeks, and the Birch two weeks,
than in England. And that at Paris, the Elder, the Elm, the
Chestnut, and the Mulberry are from two to four weeks sooner,
but the Birch and Oak are some days later than in England.

However, the different times of leafing of these trees will
be more clearly understood from the annexed comparative
Table.

Leafing.

Elder....

Elm

Birch....
Beech....
Lime . ...

Oak

Chestnut
Mulberry

Upsal.

Mar.1-8
Mar. 15

Naples.

Jan. 1—15
Feb.l— 8

May 1—8 March 15
May 1—8! March 15
May 1—8] March 15
May 1—8 April 1—8

Paris.

Feb. 14

March

April

May

March

May

Selborne.

Catsfield.

March 16 March 8
April 3 April 25

Aprii 23

June 4

May 9

May 31

Stratton.

April 6
March 29
April 23
April 13
April 26
April 21

England

March 1 2
April 15
March 29
May
April 13
April 26
April 21
June 2

of the Climate of 'Naples upon the Periods of Vegetation. 49

The last column gives the medium between the mean day
of White's observations at Selborne, that of Mark wick's at
Catsfield, and that of Marsham's at Stratton, which may there*
fore be taken with considerable accuracy for the regular date
of the appearance of the leaves of those trees in the southern
and eastern divisions of England, and, indeed, in England in
general, excepting, perhaps, its extreme northern parts.]

On comparing the times of leafing of the same trees in
different years near Naples, it will easily be seen that this
period of vegetation varies according to the temperature which
has prevailed during the months of January, February, and
March. Thus, for example, in the year 1807, these three
months having continued very cold, the Elder opened its buds
at the beginning of February ; the Elm and the Filbert showed
their leaves at the end of the same month ; the Birch, the
Beech, the Oak, and the Lime were not seen in leaf till towards
the middle of April. On the contrary, in the year 1808, the
same months having been extremely mild, the frondescence
of the same trees took place successively fifteen days earlier.
Finally, in 1810, the thermometer in the beginning of March
having risen to 15° Reaumur (or nearly 66° Fahrenheit), in
the course of the same month the leaf-buds of those trees
which usually open in April, were observed to have fully ex-
panded themselves.

[Now, in order to ascertain more correctly the true time, in
which the leafing of these trees is wont to occur about Naples,
let us take the mean dates of the different years given by
Tenore, and the results are as follows :

Leafing.

A.

as before.

1807.

B.

1808.

Mean of
A and B.

True
Mean.

England.

Elder...

Elm

Birch...
Beech...
Lime ...
Oak

Jan. 1—15 Feb. 1—8
Feb. 1—8 Feb. 2 1—28
March 15 April 8—15
March 15 April 8— 15
March 15 April 8—15
April 1—8 April 8—1 5
i

Jan. 17—24
Feb. 6—13
Mar.24 — 31
Mar.24— 31
Mar.24— 31
Mar.24— 31

Jan. 8—20
Feb. 4—9
Mar.15— 27
Mar.15— 27
Mar.15— 27
Mar.27toAp.4

Jan. 14
Feb. 6
March 21
March 21
March 21
March 31

March 12
April 15
March 29
May 1
April 13
April 26

Hence, by the above comparison of the true mean dates
with those in England, we find that near Naples the Elm is
earlier by about nine weeks, the Elder eight weeks, the Beech
six weeks, the Lime three weeks, the Oak nearly four weeks,
and the Birch only one week, than with us.]

But, likewise at Naples, there are not wanting several sorts
of trees which are always very late in developing their leaf-
buds. I will mention Acer platanoides and A. Lobelli, which
having been transplanted from the high mountains, where

Third Series. Vol. 5. No. 25. July 1834. H

50 Mr. J. Black wall's Characters of some

they grew naturally, to the Royal Botanical Garden, annually
retain their native slowness* in leafing; in as much as the
first does not open its buds until the end of April, and the
second keeps them closed to the end of the early part of May.
The same circumstance has happened to the Red Lime tree
{Tilia intbra?) originally brought from Hungary, and which
in the Botanic Garden keeps its buds unexpanded till after
the beginning of May.

[To be continued.]

IX. Characters of some undescribcd Species of Araneidae.
By John Blackwall, Esq., F.L.S., Sf-c.f

Tribe, Tubitel^:, Latreille.

Genus, Drassas, Walckenaer.

Drassus cupreus.

CEPHALOTHORAX oval, convex above, thinly covered with fine, short
hairs, marked with slight furrows on the sides, and a narrow, longi-
tudinal indentation in the medial line of the posterior region. Eyes dis-
posed in front in two transverse rows somewhat curved, having their con-
vexity directed backwards; the posterior row is rather the longer of the
two, the intermediate eyes, which are oval, and nearer to each other than
they are to the lateral eyes of the same row, forming a quadrangle with the
intermediate eyes of the anterior row. Mandibles strong, conical, armed
with a few teeth on the inner surface, and projecting a little forwards.
Maxillae long, convex at the base, underneath, enlarged externally where
the palpi are inserted, and at the extremities, which are obliquely truncated
on the inner side ; they are depressed and contracted in the middle, and
curved towards the lip, which is longer than broad, and truncated at the
apex. Pectus ovaL Legs robust, moderately hairy, and provided with a
few sessile spines; the fourth pair is the longest, then the first, the third
pair being the shortest. Each tarsus has a climbing apparatus on the under
side, and two pectinated claws at its extremity. A single dentated claw
terminates each palpus. These parts are of a pale reddish brown colour,
a fine line of a blackish hue occurring on the margins of the cephalothorax,
and a band of the same tint bordering the pectus and lip. Abdomen ob-
long oval, thickly covered with short hairs of a bright reddish copper-co-
lour, the under part being the palest ; at the anterior extremity, conti-
guous to the cephalothorax, is a tuft of long, deep black hairs, a band of a
blackish hue, broad before and tapering to a point behind, extending from
it, along the medial line of the upper side, rather more than half the
length of the abdomen. In some specimens this band is not perceptible.

* This is also the case with the common Birch tree, which, and Acer
ptatanoidcs, according to Linnaeus, "habitant in Europafrigidiore." Being
natives of a very cold climate, these trees, although growing in warmer
countries, as Naples, Paris, &c, still retain in a remarkable manner their
naturally late frondescence ; therefore, it seems that heat cannot produce
such an effect on this period of vegetation, as it has been shown to do on
germination. — J. H.
t Communicated by the Author.

undescribed Species of Araneidse. 5L

Plates of the spiracles large and of a pale yellow colour. Spinning raam-
mulae prominent and cylindrical, the inferior pair appearing to be the
longest when in a state of repose.

Length, from the anterior part of the cephalothorax to the extremity of
the abdomen, £ths of an inch; length of the cephalothorax £; breadth ^;
breadth of the abdomen I •; length of a posterior leg- 4- J length of a leg of
the third pair g.

The male resembles the female in colour, but as the fifth or terminal
joint of the palpi, in all those individuals which have fallen under my ob-
servation, has been ovate in figure and simple in structure, it is evident
that they had not attained maturity.

This species, which has a close affinity with Drassus sylvestris, I have
found inclosed in white, silken tubes, of a fine, compact texture, attached
to the inferior surface of stones and fragments of rock, in the neighbour-
hood of Manchester, and near Llanrwst in Denbighshire.

Tribey Inequitelje, Latreille.
Genus, Theridio?i, Walckenaer.

Theridion riparium.

Cephalothorax inversely heart-shaped, convex and glossy above, with a
large indentation in the medial line of the posterior region. Mandibles
small, conical, perpendicular. Maxillae obliquely truncated on the outer
side at the extremity, and inclined towards the lip which is quadrate.
Pectus heart-shaped. Palpi short and robust. These parts are of a red-
brown colour, the cephalothorax and pectus being much the darkest. Legs
strong; the first pair is the longest, then the fourth, the third pair being
the shortest ; they are of a yellowish brown colour, with broad bands of
red-brown. Eyes situated on the anterior part of the cephalothorax ; four,
which are intermediate, form a square, the two in front being seated on
a protuberance; the other four are disposed in pairs on the sides of the
square; the eyes constituting each pair are placed obliquely on an eminence
and are contiguous. The abdomen, which is thinly covered with short
hairs, is remarkably convex, projecting over the base of the cephalothorax;
it is red-brown above mottled with black and white, and is bisected by an
irregular, transverse, white line, interrupted in the middle by a triangular,
black spot, between which and the spinners is a curved, transverse, black
line; under side of the abdomen brownish black with a transverse band of
a red-brown colour near the spinners. Plates of the spiracles red-brown.

Length, from the anterior part of the cephalothorax to the extremity of
the abdomen, ^th of an inch ; length of the cephalothorax -fa} breadth TV;
breadth of the abdomen Tv ; length of an anterior leg -^ ; length of a leg
of the third pair y^.

The female of this species spins an irregular web of fine glossy lines un-
der the projections of broken, precipitous banks, in the woods about Oak-
land. In the month of August she constructs a long, slender, conical, up-
right tube of silk, of a slight texture, measuring from one and a half to
two and a half inches in length, and about half an inch in diameter at the
lower extremity; it is closed above, open below, and thickly covered on
the outside with bits of earth, minute pebbles, dried leaves, flowers of
heath, &c. Suspended from the projection of the bank to which the web
is attached by strong lines connected with the apex, and united to the web
laterally by numerous slender threads, the tube is held firmly in its position.
In the upper part of this curious domicile the spider fabricates two or three
slight, globular cocoons of yellowish white silk, about TVth of an inch in

H2

52 Mr. J. Blackwall on some undescribed Species of Araneidas.

diameter, in each of which 6he deposits from ten to thirty 6pherieal eggs
of a yellowish white colour. The young continue with the mother till they
have attained a considerable size, and are provided by her with prey, as
the contents of the tube plainly indicate. I have not succeeded in cap-
turing an adult male of this species of Theridion,

Genus, Neriene, mihi.
Neriene nigra.

Cephalothorax inversely heart-shnped, inclining to oval, convex above,
glossy, marked on the sides with slight furrows diverging from the superior
part towards the lateral margins, prominent in front, depressed in the
posterior region, with an indentation in the medial line. The intermediate
eves of the anterior row are very minute and near to each other. Mandi-
bles strong, conical, armed with teeth on the inner surface, and slightly
inclined towards the pectus, which is heart-shaped. Maxillae enlarged at
the extremity, and inclined towards the lip, which is semicircular and pro-
minent at the apex. These parts are of a brownish black colour, the man-
dibles and maxillae having a faint tinge of red. The legs and palpi are pro-
vided with hairs and a few delicate spines, and are of a red-brown colour.
Each tarsus has three claws at its extremity; the two superior ones are
minutely dentated, and the inferior one is inflected near its base. Abdo-
men oval, convex above, projecting over the base of the cephalothorax j
it is thinly clad with hair, glossy, and brownish black. Plates of the spira-
cles of a brown colour.

Length, from the anterior part of the cephalothorax to the extremity of
the abdomen, -r^th of an inch ; length of the cephalothorax -^ ; breadth
■3V; breadth of the abdomen 7v ; length of an anterior leg £ ; length of a
leg of the third pair -fa.

The male resembles the female in colour, with the exception of its legs,
which are redder. The relative length of the organs of progression is the
same in both sexes. The third joint of the palpi is long and clavate ; the
fourth is strong, and is elongated before into a narrow, oval process taper-
ing to a point, which extends in front of the fifth joint j this latter joint is
oval, convex externally, concave within, comprising the sexual organs;
they are highly developed, complex with spiny processes, one of which, on
the outer side near the extremity, is curved into a circular form, and are
of a dark red-brown colour.

Specimens of this spider were captured in the autumn of 1833, on posts
and rails at Oakland, and at Crumpsall Hall.

Neriene pygmcca.

Cephalothorax oval, glossy, convex above, with the sides somewhat de-
pressed, and a small indentation in the medial line of the posterior region.
Mandibles strong, conical, armed with teeth on the inner surface, and
slightly inclined towards the pectus, which is heart-shaped. Maxillae en-
larged at the extremity, and inclined towards the lip, which is semicircular
and prominent at the apex. The cephalothorax, pectus, and lip are brown-
black, the mandibles and maxillae being of a dark reddish brown colour. The
legs and palpi are provided with hairs and fine spines, and their colour is
bright rufous. Each tarsus has three claws at its extremity ; the two su-
perior ones are minutely dentated, and the inferior one is inflected at its
base. Abdomen oval, projecting a little over the base of the cephalotho-
rax ; it is sparingly clad with hair, glossy, and brownish black. Plates of
the spiracles brown.

length, from the anterior part of the cephalothorax to the extremity of

Geological Society, 53

the abdomen, -?T\h of an inch ; length of the cephalothorax -fa ; breadth
fa ; breadth of the abdomen fa ; length of an anterior leg £ : length of a
]eg of the third pair fa.

The male resembles the female in colour, and the relative length of its
legs is the same as in that sex. The third and fourth joints of the palpi
are short, the latter being much the stronger, and prominent in front ; the
fifth joint is oval, convex externally, concave within, comprising the sexual
organs, which are highly developed, complicated in structure, and of a dark
reddish brown colour.

I found this minute species in considerable abundance in the month of
March 1833, on iron rails at Crumpsall Hall; and in the autumn of the
same year I procured specimens in the vicinity of Llanrwst.

Tribe, ORB™,! Latreil]e>
(jrenus, Lmyphia, J

Linyphia pusilla.

As this spider bears a striking resemblance to Linyphia minutat\t will suf-
fice to point out those particulars in which it differs from that species. It
is smaller, of a more slender form, and the colour of the legs and palpi is
plain, yellowish brown. The upper part of the abdomen is pale brown,
and along the middle extends a series of strongly marked, brownish black,
angular lines, having their vertices directed forwards; the sides and under
part are dark brownish black, and the plates of the spiracles are of a brown
colour. The female has no cylindrical appendage in connexion with the
sexual organs.

Length, from the anterior part of the cephalothorax to the extremity of
the abdomen, -^th of an inch; length of the cephalothorax fa ; breadth
fa > breadth of the abdomen fa ; length of an anterior leg £ ; length of a
leg of the third pair £.

The abdomen of the male is more slender, and darker coloured than
that of the female, but the relative length of its legs is the same; their ab-
solute length, however, is greater, an anterior one measuring |th of an
inch. The third and fourth joints of the palpi are short, the latter being
very strong, and prominent in front; the fifth joint is convex externally,
concave within, comprising the sexual organs, which are highly developed,
complicated in structure, and of a red-brown colour.

This species is common in autumn on rails in the vicinity of Manchester,
and in the neighbourhood of Llanrwst.

Crumpsall Hall, Feb. 10, 1834.

X. Proceedings of Learned Societies,

GEOLOGICAL SOCIETY.

Mr. GreenougJCs Anniversary Address.
[Continued from vol. iv. p. 454.]

AMONG the subjects which have for some years past engaged the
thoughts of geologists, none perhaps has excited so general and
intense an interest as the Theory of Elevation. I shall avail myself,
therefore, of the present occasion to lay before you a connected
statement of the scattered facts and opinions upon which it rests.

On entering upon this subject, it is necessary to understand di-
stinctly what is meant by Elevation. Definitions have recently
been decried, I think unwisely. The formation of definitions,
it has been said, and the establishment of unerring distinctions

54? Geological Society.

are among the last, and not the first steps of systematic know-
ledge. Equally true, and far more salutary is the lesson that sci-
ence cannot be advanced by equivocation. As in trading con-
cerns fixed weights and measures are necessary guards against
fraud, so in philosophical investigation words of definite meaning
are indispensable securities against sophistry and self-delusion.
Euclid did not end, he began with defining. Mathematical certainty
has no other basis than mathematical precision, and the greater part
of those absurdities which from time to time attach themselves to
all other branches of knowledge derive their subsistence from am-
biguity of language and a dearth of definition.

A torrent brings down a quantity of alluvial matter, and the plain
on which it rests is said to be elevated.

An opening occurs in the earth ; ejected ashes, scoriae and lava
accumulate around it ; a Monte Nuovo is formed ; and the area it
occupies is said to be elevated.

By the persevering labour of polypi, a coral reef gradually attains
the surface of the ocean ; and the fabric so constructed is said to be
elevated.

A porous rock covers a rock that is not porous; the rain filters
through the superincumbent bed; springs break out in the sub-
jacent ; and at last, for want of support, the porous rock, ori-
ginally horizontal, acquires an inclined posture, one end being di-
rected upwards, the other downwards ; and the whole is said to be
elevated.

An earthquake takes place at the mouth of a river; the sea is
violently affected ; a bar is formed at the entrance of a harbour
from the washing in of new alluvion, or from some obstruction to
the escape of the old; where a ship floated, a barge is aground ; and
the land is said to be elevated.

Such instances of Elevation are common and incontestible; but
elevation of this kind is quite different from that which forms the
subject of my present inquiry.

By the term Elevation, I mean only the removal of any given ob-
ject from a lower level to a higher level; consequently it is neces-
sary, before I speak of an object as elevated, that I should be pre-
pared to show two things : first, the level at which it has stood ;
secondly, the level at which it stands.

That I might form a right opinion of the theory, the merits of
which I am about to investigate, I have endeavoured to determine
the site, the number and the magnitude of those multifarious objects
to which the attribute of elevation is continually applied. The at-
tempt has proved unsuccessful: they are indefinite in place, in form,
and in dimension. That Mountains should be elevated is not sur-
prising, but we are familiarized also with Valleys of elevation*. In
ancient times an Island (Delos, for example,) would alternately

* Valley* of this nature are properly called by Mr. Scropc '* valleys of
" elevation and subsidence," or more concisely, " anticlinal valleys." See
Scrope on Volcanoes, p. 213.

Geological Society. 55

emerge from, and plunge beneath, the sea. Extensive Provinces,
nay, entire Kingdoms, now perform the same feat. The existence
of Craters of Elevation is by some still considered doubtful ; but it
is an accredited fact that Mountains and Mountain Chains have
risen, either per saltum or per gradus. All the Strata have been
raised ; and all Unstratified Rocks would doubtless have been raised
also, but that some have risen of themselves. The Bed of the Sea
has been elevated again and again. Continents too have been raised,
though " by an operation distinct from that which raised the Pri-
" mary Strata."

The arguments advanced in favour of these doctrines are derived
either from observation, or from induction.

It is stated by Von HofF, that in the year 1771 several tracts of
land were upraised in Java, and that a new bank made its appear-
ance opposite the mouth of the river Batavia. The authorities cited
for the effect of this and several other earthquakes mentioned in the
same place by this author, are Sir Stamford Raffles, John Prior's
Voyage in the Indian Seas, and Hist. Gen. des Voy. torn. ii. p. 401.
Mr. Lyell has cited the first of these only, but no such fact is noted
in either edition of the work of Sir Stamford Raffles. The other
authorities adduced by Von HofF I have been unable to consult;
but from the Appendix to the Batavian Transactions (which contains
an apparently authentic account of all the recorded earthquakes
that have taken place in Java during a century and a half,) it would
seem, that in the year 1771, in which the uprising is said to have
happened in that island, there was no earthquake at 'all.

The Earthquake of Chili in 1822 has been so much* insisted on,
that it requires detailed consideration. Of this event an account
by Mrs. Graham is inserted in our Transactions. I am deeply sensible
of the honour that lady conferred on the Society by her obliging
compliance with the request which elicited her narrative, and it is
only the importance of its contents which could induce me to sub-
ject them to the test of rigid examination.

According to this account " it appeared on the morning after the
" earthquake, that the whole line of coast from north to south, to the
" distance of above 100 miles, had been raised above its former level."
But by what standard was the former level ascertained? who on
the morrow of so fearful a catastrophe could command sufficient
leisure and calmness to determine and compute a series of changes,
which extended 100 miles in length, and embraced (according to
a statement in the Journal of Science,) an estimated area of 100,000
square miles? How could a range of country so extensive be sur-
veyed while the ground was still rocking, which it continued to
do on that day, and for several successive months? What was the
average number of observations per square mile? Who made, checked
and registered them ? By what means did the surveyors acquaint
themselves with what had been the levels and contour before the

* Bakewell's Geology, edition 4, pp. 98. 504. Lyell, vol. i. pp. 401. 455.
De la Beche's Manual, edition 2. Scrope on Volcanoes, p. 209.

56 Gedlogical Society.

catastrophe took place, by which, as we are told, all the landmarks
were removed, and the soundings at sea completely changed?

Mrs. Graham states that by the dislodgement of snow from the
mountains, and the consequent swelling of rivers and lakes, much de-
tritus was brought to the coast ; and further, that sand and mud were
brought up through cracks to the surface. Amid so many agents it
should not be easy to assign to each, its share in the general result.

That fishes lay dead on the shore may prove only that there had
been a storm. In her published travels, Mrs. Graham represents
them as lying on the beach, which may very well have been thrown
up, as the Chesil bank has been, by a violent sea. Some muscles,
oysters, &c, still adhered, she says, to the rocks on which they grew ;
but we know not the nature or dimensions of these rocks, whether
fixed or drifted. The occurrence of a shelly beach above the actual
sea-level is an observation which must not be lost sight of. I pro-
pose to speak of it hereafter : in the mean time be it recollected, that
these beaches are said to occur along the shore at various heights,
along the summit of the highest hills, and even among the Andes.

Neither in the paper of Mrs. Graham, nor in the anonymous ac-
count published about the same time in the Journal of Science, can
I find any paragraph to justify the position (which, from the se-
ductive character of the work* in which it appears, may, if not now
assailed, soon be deemed unassailable,) that a district in Chili, one
hundred thousand miles in area, " was uplifted to the average height
" of a foot or more 5 and the cubic contents of the Granitic Mass
" added in a few hours to the land." By what means we get the
average I do not know. Mrs. Graham says the alteration of level at
Valparaiso, was about three feet ; at Quintero, about four feet: but
the granitic Mass! has the geological structure of Chili been suffi-
ciently examined to assure us that Granite extends over one hun-
dred thousand square miles ?

In the well-known work of Molina, a Jesuit who passed the
greater part of his life in Chili, and wrote a natural history of that
country, I find no ground for supposing that in any earthquakes
which took place there from the time the Spaniards first landed on
its shores to the date of his publication, any similar phenomena had
been noticed. Moreover, the statement of Mrs. Graham, and of the
writer before alluded to, respecting the Elevation of land which oc-
curred during the earthquake of 1822, has not been confirmed by
Captain King, nor by any naval officer or naturalist who has since
visited that region, though many have visited it who had heard the
circumstance, and who would willingly have corroborated it if they
could. But they saw no traces of such an event j and the natives
with whom they conversed, neither recollected nor could be induced
to believe it.

The 16th number of the " Mtrcurio Chileno" a scientific Journal,
contains an account of this earthquake, by Don Camilo Enriquez,
which I have not been able to procure. A later number refers to this

* Lvell, vol. i. p. 473.

Geological Society. 57

account, and to another published in the Abeija Argentina, a work
of considerable reputation, which, by the kindness of Mr. Woodbine
Parish, I have been enabled to consult. The account there given of
the earthquake of 1822, is strongly recommended to the reader,
" as a sensible straight-forward description of what actually took
" place, without the high colouring in which ignorance and terror
" and exaggeration are apt to indulge."

No notice is here taken of the permanent Elevation of the Land,
and the account concludes thus:

" The earth certainly cracked in places that were sandy or
" marshy ; I saw cracks too in some of the hills, but mostly in
" the low nook where much earth had run together ; the sea was
" not much altered, — it retired a little, but came back to its old
" place. Don Onofri Bunster, who, on the night of the earthquake,
i( was walking on the shore at Valparaiso, in front of his house, had
" a mind to go up on the hill, but could not, so great was the quan-
" tity of falling dust and stones: he repaired to his boat therefore,
" and with some difficulty got aboard; this done, he made obser-
" vations on the motion of the sea ; on sounding, the depth was
" thirteen fathoms ; he heaved the lead a second time, and the
" depth was no more than eight fathoms: this alternate ebbing and
" flowing lasted the whole night, but did not the slightest harm on
" shore."

These are the Only cases I remember to have met with, in which
the testimony of eye-witnesses has been adduced to prove the Rise
of land by Earthquakes. That such Rise may have taken place, at
different times, without being recorded, perhaps even without being
observed, is not very improbable ; but if I am to pronounce a ver-
dict according to the evidence, I believe there is not as yet one well
authenticated instance in any part of the world, of a non-volcanic
Rock having been seen to rise above its natural level in consequence
of an Earthquake.

Before I quit this subject, it may not be amiss to mention, that
on comparing the times at which the successive shocks took place
in Chili, as given by Mrs. Graham, and the other authorities to which
I have had occasion to refer, the discrepancy is extraordinary.

I have already intimated in a few words, my opinion as to the
sense in which land can be said to be elevated by means of Volcanoes.
Of these, Vesuvius is perhaps the most constantly observed ; and
among the innumerable authors who have described its effects, from
the time of Pliny down to the present day, not one pretends that
the Apennine limestone, close at hand, has been in the least raised
by that volcano. We shall do well to bear this in mind, when we
have occasion to consider the height at which tertiary shells are
found on Etna. That those shells belong to beds thrown up by
Etna, is a doctrine founded upon induction, not upon experience.
As far as experience goes, we have no reason to think that Etna,
in its most violent paroxysms, will ever raise those tertiary strata
above their present level.

Third Series. Vol. 5. No. 25. July 1834. I

58 Geological Society.

Leaving these scenes of paroxysmal violence, let us next inquire,
whether there may not be going on, in the calmest seasons and in
the stillest countries, a chronic and almost imperceptible impulsion of
land upwards.

As early as the time of Swedenborg, who wrote in 1715, it was
observed that the level of the Baltic and German Ocean was on the
decline. About the middle of the last century an animated and
long-continued discussion took place in Sweden, first as to the cause
of this phenomenon, and then as to its reality. Hellant, of Tornea,
who had been assured of the fact by his father, an old boatman, and
who afterwards witnessed it himself, bequeathed all he had to the
Academy of Sciences, on condition that they should proceed with
the investigation : the sum was small, but the bequest answered the
purpose. Some of the members of the Academy made marks on
exposed cliffs and in sheltered bays, recording the day on which the
marks were made, and their then height above the water. The Baltic
affords great facility to those who conduct such experiments, as there
is no tide, nor any other circumstance to affect its level, except
unequal pressure of the atmosphere on its surface and on that of
the ocean : this produces a variation which is curiously exemplified
at Lake Malar near Stockholm. As the barometer rises or falls, the
Baltic will flow into the lake, or the lake into the Baltic. The va-
riation resulting from the inequality of atmospheric pressure, how-
ever, is trifling. In sheltered spots, mosses and lichens grow down
to the water's edge, and thus form a natural register of its level.
Upon this line of vegetation marks were fixed, which now stand in
many places two feet above the surface of the water.

In the year 1820-1, Bruncrona visited the old marks, measured
the height of each above the line of vegetation, fixed new marks,
and made a Report to the Academy. With this Report has been pub-
lished an Appendix by Halestrom, containing an Account of Mea-
surements made by himself and others along the coast of Bothnia.
From these documents it would appear, 1. That along the whole
Coast of the Baltic the water is lower in respect to the land than it
used to be. 2. That the amount of variation is not uniform. Hence
it follows, that either the Sea and Land have both undergone a
change of level, or the Land only ; a change of level in the Sea only-
will not explain the phenomena.

A quarter of a century has now elapsed since Mr. von Buch de-
clared his conviction that the surface of Sweden was slowly rising all
the way from Frederickshall to Abo, and added that the Rise might
probably extend into Russia. Of the truth of that doctrine the pre-
sumption is so strong, as to demand, that similar experiments and
observations should be instituted and continued for a series of years
in other countries, with a view to determine whether any change of
level is slowly taking place in those also. The British Association for
the Advancement of Science have already obeyed the call. A com-
mittee has been appointed to procure satisfactory data to determine
this question as far as relates to the coasts of Great Britain and Ire-

Geological Society, 59

land, and I cannot but hope that similar investigations will also be
set on foot along the coasts of France and Italy, and eventually be
extended to many of our colonial possessions.

The inductive arguments in favour of the Elevation of land, what-
ever the size, and whatever the amount of Rise, are founded chiefly
on the following circumstances: 1. The height of sedimentary beds
and marine bodies, whether corresponding or not to those of ad-
jacent seas, or of the actual globe. 2. The height of terraces re-
sembling sea beaches. 3. The height of ripple marks. 4<. The
change of posture which horizontal strata undergo in the neigh-
bourhood of " unstratified rocks." 5. The various heights at which
the same rocks occur in different parts of their course. 6. Thean-
ticlinical posture of strata frequent in, though not confined to,
mountain chains. 7. The arched or domed configuration of some
strata. 8. The occurrence of coral, apparently recent, high above
the present surface of the sea. 9. The position of ancient buildings,
viz. the temple of Serapis at Puzzoli, &c. I have not time to con-
sider these arguments in detail ; each deserves to form the subject
of a separate treatise. Some of them prove not Elevation, but only
change of level, which Subsidence would explain equally well. Some
prove local disturbance, whereby one portion may have been thrown
up, the other down. Some again afford a fair presumption of real
local Elevation or Ascent. Most of them are good to a certain point :
all are continually overstrained; and I am frequently astonished to
observe how prodigious the weight, how slender the string that
supports it.

The assigned Causes of Elevation are exceedingly various. One
author raises the bottom of the sea by earthquakes ; another, by sub-
terranean fire ; another, by aqueous vapour j another, by the contact
of water with the metallic bases of the earth and alkalis. Heim
ascribes it to gas ; Playfair, to expansive force acting from beneath;
Necker de Saussure connects it with magnetism ; Wrede, with a slow
continuous change in the position of the axis of the earth; Leslie
figured to himself a stratum of concentrated atmospheric air under
the ocean, to be applied, I suppose, to the same purpose.

It is impossible within the narrow limits of this discourse, that I
can enter into the merits of these and other hypotheses seriatim. I
must therefore throw them into two classes, the first of explosive
forces, the second of sustaining forces j they are one and the same in
Plutonic language, but still it will be convenient to separate them.

That explosive forces exist, or may exist, under the surface, no one
can deny j but I cannot adopt the opinion (however high the autho-
rity from which it comes,) that ** in volcanic eruptions we find a power
" competent to raise Continents out of the ocean." The force we find in
volcanic eruptions is limited in time, place and action ; it fuses bodies
of easy fusibility ; it tosses up those that are refractory, and thus
forms either a current of lava or a shower of stones, scoriae and ashes.
What resemblance is there between this operation and the rise of a
continent ? With more propriety might it have been said that in a mole-
hill we behold the action of a cause competent to raise mountains.

12

60 Geological Society.

If by Continent is meant a whole Continent, and nothing but a
Continent, its rise, provided this happened only once, would seem
difficult to understand ; but to me still more incomprehensible is
the confident assurance we continually receive from writers of high
and deserved reputation, that this event has happened again and
again. Before we admit the Submersion of a continent, we must ad-
mit either that at a period immediately preceding that catastrophe,
there existed under the land a cavity large enough to contain the con-
tinent about to be submerged, or that during the process the subja-
cent beds shrunk in consequence of a reduction of the temperature,
and to such an extent that the contraction in a vertical line equalled
the distance from the level of the highest tops of the continent to
that of the surrounding ocean. In like manner, before we can admit
the Elevation of a continent, we must admit either that, at a period
immediately preceding that catastrophe, there happened an inroad of
sustaining matter equal in thickness and in extent to the Continent
about to be uplifted, or that during the process the subjacent beds
expanded in consequence of an increase of temperature, and to such
an extent that the expansion in a vertical line equalled the distance
from the level of the highest tops of the continent to that of the sur-
rounding ocean. These therefore are the events which we are taught
to credit, as having taken place again and again, notwithstanding the
tendency which caloric has to diffuse itself, and the apparently un-
altered dimensions of the fissures and local caverns by which the
strata are so often separated or intersected.

I will not expend more of your time in arguing against such doc-
trines. All men are more or less lovers of the marvellous, but few, I
think, will upon reflection approve such marvels as these.

Solids, fluids and aeriform substances exist, we know, in the interior
of the earth, and expand by heat, which exists there likewise. All of
these, therefore, are fit Agents of Elevation, subject to certain conditions.

Dr. Daubeny attributes the liquefaction of lava, the throwing up of
ashes, and all other phenomena of disturbance attendant on volcanic
eruptions, to the Action of Water upon the Metallic Bases. This cause
is not opposed to experience, and appears well proportioned to the
effect, which is sudden, violent, occasional, temporary, accompanied
by heat and by flame. To me, at least, it seems far more satisfactory
than the explanation of those who ascribe the effect to the Elastic
Power of Subterranean Fires, repressed in one place and relieved in
another, or to the Undulations of a Heated Nucleus.

A heated Central Nucleus is a mere invention of fancy, traceable, I
believe, to no other source than the hope of obtaining a good argument
from the multiplication of bad ones. To the Huttonian and every
other geological sectary who relies on this postulate, I say, be cau-
tious j " incedisper ignes dolosos."

The only observation I recollect to have met with in favour of cen-
tral heat is, that the deepest mines are the warmest — be it so ! Might
not a geologist by parity of reasoning argue thus ? — In travelling
from Rome to Chamonix, the country becomes continually more and
more mountainous ; some of the peaks of Chamonix are from ten to

Geological Society, 61

fifteen thousand feet above the level of the sea. Imagine, therefore,
what they must be at Hamburgh!!

If mines derive their temperature from heat lodged in the centre of
the earth, the temperature ought to vary with their distance from the
centre, and therefore, since the earth is an oblate spheroid, the mines
of Scandinavia ought at the same depth from the surface to be propor-
tionally warmer than those of tropical countries j a result which has
never been, I believe, even suspected.

The existence of Central Heat in the sense and to the extent as-
sumed in the Huttonian theory, is contrary to all our experience. If
Heat there be in the Centre of the globe, it must have the properties of
heat, and none other. I ask not how the Heat originally was lodged
in that situation, for the origin of all things is obscure j but I ask why,
in the countless succession of ages which the Huttonian requires, the
Heat has not passed away by conduction, and if it has passed away, by
what other heat it has been replaced?

Dr. Chalmers in speaking of Sir Isaac Newton, observes, that it was
a " distinguishing and characteristic feature of his great mind, that it
" kept a tenacious hold of every position which had proof to substan-
" tiate it j but a more leading peculiarity was, that it put a most de-
" termined exclusion on every position destitute of such proof. The
" strength and soundness of Newton's philosophy was evinced as much
" by his decision on those doctrines of science which he rejected, as
" by his demonstration of those doctrines of science which he was
" the first to propose. He expatiated in a lofty region, where he met
*f with much to solicit his fancy, and tempt him to devious speculation.
" He might easily have found amusement in intellectual pictures, he
" might easily have palmed loose and confident plausibilities of his
" own on the world. But no, he kept by his demonstrations, his mea-
" surements, and his proofs."

Gentlemen, let us, as far as is consistent with the nature of geolo-
gical investigation, show the strength and soundness of our philo-
sophy in the same manner.

That Heat of considerable intensity prevails occasionally, in certain
places, at some depth, is all that we have as yet clearly established.
Whether that Heat is permanent, whether it is generally diffused,
whether it is central, are questions of mere speculation.

Intimately connected with the hypothesis of Central Heat is that of
Refrigeration.

It has been observed by one of our members, that " the Remains both
" of the animal and vegetable kingdom preserved in strata of different
" ages, indicate that there has been a great Diminution of Tempera-
" ture throughout the northern hemisphere, in the latitudes now oc-
u cupied by Europe, Asia and America ; the change has extended to
" the arctic circle as well as to the temperate zone; the heat and
" humidity of the air, and the uniformity of climate, appear to have
" been most remarkable when the oldest strata hitherto discovered
" were formed. The approximation of a climate similar to that now
" enjoyed in these latitudes, does not commence till the aera of the
" formations termed tertiary ; and while the different tertiary rocks

62 Geological Society.

*' were deposited in succession, the Temperature seems to have been
4< still further lowered, and to have continued to diminish gradually
" even after the appearance of a great portion of existing species upon
" the earth." The little knowledge we have of the fossil productions
of countries south of the temperate zone, induces me to believe that
these observations are as applicable to the southern hemisphere as to
the northern.

This Refrigeration, one of the most undoubted facts in geology, is
supposed by the Huttonians, and if I mistake not, by M. Elie de Beau-
mont and others, to arise from a decrease of the Central Heat j an
opinion, however, which cannot, I think, be supported.

We know of one method only by which Central Heat, if it exists, can
pass from the earth, viz. by Radiation. It cannot pass by Conduction.
Conduction implies conductors, which in empty space are not to be
procured *, but the Radiation of heat, at low temperatures, is so slight
that it is scarcely sensible at 100° of Fahrenheit's thermometer,
a temperature twice as great as the medium temperature of the sur-
face of the globe at this time. The Temperature of the earth's surface
has been shown by Fourier to be as constant as are the dimensions
of its orbit, and the period of its annual revolution. Laplace observes,
that our planet has undergone no- Contraction of Size during the last
2000 years ; consequently there has been no sensible Refrigeration
during that period, and the last Seculum of M. de Beaumont has
already extended to more than twice the length of a Millennium.

Another argument, or rather postulate, has been adduced in fa-
vour of Central Heat, — the Fusion of Unstratified Rocks, and their
forcible Injection into the Stratified.

Gentlemen, I have confessed to you again and again, that I am not
aware, nor has any one as yet informed me, by what test Stratified
and Unstratified rocks can be distinguished ; the only test I know is
the good will and pleasure of those who make the distinction. The
followers of Pluto seize and appropriate to his use as many rocks as
they think proper. By virtue of such seizure, these Rocks become ne-
cessarily Unstratified : why so ? because if Stratified they would be no
longer Plutonic. Stratification I know is a question to be determined
not by the senses but by the fancy j otherwise, I would say, that the
magnificent range of basaltic cliff, which extends from the county of
Derry along the coast of Antrim as far as Fairhead, is as distinctly
stratified as any mountain-limestone, oolite or chalk in Great Britain.

However, I waive this objection as it leads me away from my sub-
ject, and return to the consideration of Central Heat. Have those
who believe in this agent ever taken into their account the nature
of the substances said to have been fused ? Many of the trap rocks,
not all of them, (for the family is large, and many of its members have
been introduced into it, not by nature but by adoption,) I attribute
to the agency of the causes which have produced lava, causes which,
comparatively speaking, I do not believe to be very deep-seated.

• See Comparative View of the Huttonian and Neptunian Systems of
Geology.

Geological Society, 63

These rocks I put out of consideration for the present ; the remarks
about to be offered apply to granite and its congeners, under which
head I would give to every one full liberty to include or reject quartz
rock, gneiss, mica slate, eurite, cipollino, hornblende rock, serpen-
tine, &c. Some or all of these, it is the bounden duty of Central Heat
to fuse and to eject.

Such and so limited are the means of Chemistry, that of many sub-
stances thus brought within the sphere of our inquiries, the point of
fusion is at this day unascertained. The author of the masterly publica-
tion before adverted to, brought together many useful observations
upon this subject. He observes that " Lavoisier could not melt a
" particle of Carbonate of Lime by the intense heat of a burning mir-
" ror, and that Quartz, according to Saussure, requires for its fusion
" a temperature = 4043° of Wedgwood's pyrometer, Glass requiring
" at a medium only 30° of the same scale."

That the Difficulty, which here suggests itself, of providing, in the
absence even of imaginary fuel, a Supply of imprisoned Heat sufficient
to fuse the substances I have mentioned and others scarcely less re-
fractory, may be mitigated by extending the time employed in the
process, or by the aid of compression and other circumstances, I am
ready to admit; but, in the most favourable view of the case, the Heat
wanted, (when we consider the thickness and extent of these rocks,
comprising entire mountains and mountain chains,) must be prodi-
gious ; and I cannot but admire the singular taste of those geological
speculators, who, enjoying the free range of the globe, have deposited
their Caloric exactly in that spot in which it can be of least use to
them. The inconvenience of this distribution becomes still more ap-
parent when it is recollected that fusion is not all that is necessary ;
but that, when fused, these substances must be propelled in a deter-
minate direction and with sufficient force, in many instances, to raise
the bed of the sea to the height of an Alpine chain. I will not at-
tempt to point out to you the way in which this is accomplished, but
confess at once that I do not understand it.

And yet it appears certain that the surface of our planet has become
cooler and cooler, from the period when organic life commenced to
the tertiary epoch. If this cannot be explained by the Escape of Heat,
there remains only one other mode of explaining it, — a continually
diminishing Supply. The latter is the explanation offered by Mr.
Lubbock. Sir John Herschel, also, has brought into view causes
within the range of physical astronomy which, independently of a Loss
of Internal Heat, produce a slow but certain Diminution of Tempe-
rature on the surface of our globe*. These auxiliaries, however, are
insufficient.

Mr. Lyell has offered another solution of the problem, depending

* The Baobab-tree of Senegal is supposed by Adanson to have attained
the age of 5150 years, and De Candolle attributes to the Cupressa disticha
of Mexico a still greater longevity. (Lyell, vol. iii. p. 99.)

If these opinions be correct, it seems improbable that any great change
either of level or climate can have taken place at these spots within the
last 5000 years.

64 Geological Society,

not on celestial but terrestrial causes. The chapter that contains it
abounds in valuable information and ingenious reasoning 5 but when
the author tells us that* in every country " the land has been in some
" parts raised, in others depressed, by which and other ceaseless changes,
" the configuration of the earth's surface has been remodelled again and
" again since it was the habitation of organic beings, and the bed of the
" ocean lifted up to the height of the highest mountains," I cannot
but wish that he had stated this as an opinion, not as a fact.

All these theories have one defect in common j they do not meet
the whole of the case. We have to explain not only the Cooling gra-
dual during the long interval that occurred between the formation of
the carboniferous beds and the chalk, but also the Sudden Chill which
followed, and seems to have continued from that time to this. There
is yet another element to be taken into account. The coal-beds of
Melville Island contain various plants, natives of the country where
they are found, and which, if we may trust analogy, require for their
healthy growth or for their growth at all, not only tropical heat t,
but a tropical apportionment of the periods of exertion and repose.
It is a botanical impossibility that such plants could have flourished in
a region in which they must have been stimulated by months of con-
tinuous Light, and paralysed by months of uninterrupted Darkness.
The distribution of Light, therefore, as well as of Heat, must formerly
have been different from what it is at present.

To meet this further difficulty, recourse is had to physical astro-
nomy, which gives us the Precession of the Equinoxes, and a Shifting
Axis of Rotation : but the periodical changes of astronomers are insuf-
ficient to explain the phenomena to which I have just drawn your
attention. It has therefore been suggested that a greater change
may, in the course of ages, have been produced on the axis of the
earth's rotation by some foreign cause, say the Collision of a Comet.

Such change is undoubtedly possible, but of possibilities there is no
end, and we must circumscribe our researches to render them useful.
Sir John Herschel gives us no encouragement, therefore, to proceed
with this speculation. Mr. Conybeare also dissuades us from it, but
by an argument which to me at least appears inconclusive.

His argument, founded upon the lunar theory, is this, — that the
internal strata of the earth are ellipses parallel to its external out-
line, their centres being coincident, and their axes identical with that of
the surface. The present axis of the earth must therefore have been
its axis from the beginning. It may have been so, yet I should like
to be told by what process the form of the internal strata of the earth
had been so nicely determined. Possibly, however, I may not under-
stand the expression " internal Strata." All I believe to be ascer-
tained is, that of corresponding sections of the interior the density is
nearly the same, and if so, my inference is, not that the earth has

* Principles of Geology, vol. i. p. 113.

f Since this passage was written, doubts have been expressed whether the
specimens of these plants preserved at the British Museum are sufficiently
distinct to warrant the inference.

Geological Society. 65

never changed its axis of rotation, but that if it has done so, the
interior was then sufficiently pliant to accommodate itself to the
change.

A much more formidable objection to the employment of such a
cause is, that if once called in, we must take it with all its conse-
quences. The effects produced by it will not be what we wish per-
formed, but what its nature obliges it to perform. In explaining the
phenomena of Melville Island, it might render inexplicable those of
the rest of the world. If we choose to change the axis upon which the
earth revolves, let us at least fix upon the best time fordoing it; now
what is that time? immediately after the formation of the carboniferous
series ? The reduction of temperature at that epoch was inconsider-
able; tropical plants and animals are found in the lias, in the oolite
series, in the chalk. A much more convenient time would be on
the first appearance of the tertiary rocks; but however satisfactory
it might be to trace to such a cause the violent changes and disturb-
ances which appear to have taken place about that period in all other
parts of the world, I am afraid our satisfaction would be greatly di-
minished on finding that Gosau and Maestricht* escaped unhurt.

Be the cause what it may, the effect is certain. The Temperature
of the Crust of the Earth must have been higher when the Coal-mea-
sures were deposited than now, and we have reason to think it was
still higher at antecedent periods. That a considerable degree of Heat
still exists, either partially or generally, at no great distance from the
surface, appears from thermal springs and volcanoes.

I am aware that the doctrine of Internal Cavities has been regarded
as visionary j and in the extent to which it was carried by some of the
old Cosmogenists it was so; but that comparatively near to the surface,
there are, I do not say Vacuities, but large Spaces unoccupied by solid
matter, is not only probable, but almost proved. It seems, indeed, to
be a necessary consequence of the structure of the crust of the earth.
No miner has ever got to the bottom of a vein, and a vein itself is
often a half empty pipe or fissure. The correspondence of the
phases of distant volcanoes, the continuous ranges of their eruptive
openings, the vast extent of territory shaken simultaneously by their
convulsions, are so many proofs of communication below the sur-
face. The bulk of the ejected matter cannot be less than that of the
concreted ejections which we see; for at the temperature of fusion
it is greater than at a lower temperature, and for every foot of matter
ejected, it is necessary to provide a substitute in the place which
it occupied.

The continuous streams of lava which issued in Iceland, on one
occasion, attained the length of forty or fifty miles. But the bulk of
volcanic matter presented to view, does not enable us to form a
correct estimate of the quantity of matter ejected; we must take
further into account the combustible substances which have vanished,
the gases which have escaped, the dust and ashes which, projected
into the air, have fallen many miles distant from the place of explo-

* See the descriptions of these places in Geol. Trans.
Third Series. Vol. 5. No. 25. July 1834. K

66 Geological Society.

»ion*. Then only can we entertain a just idea of the Cavities that must
have been created in the interior of the earth by the escape of a mass
of matter competent to produce an Etna or a Chimboraco. Such Ca-
vities are ill suited to support such Mountains ; La Metherie therefore
supposes Cavities to be at a distance, and volcanic matter to flow
from these through long galleries and fissures of communication. Nor
have we in volcanic countries alone decisive evidence of the existence
of subterranean Cavities. No rock is exempt from Fissures : in thick
beds of limestone Fissures and Caverns are exceedingly abundant; and
the extent of these last is sometimes prodigious. Who has not heard
of the Grotto of Antiparos ? of the Caverns of Carinthia and Carniola,
the content of which amounts to some hundred thousand cubic feet?
of the Kingston Cave recently explored near Michelstovvn in Ireland ?

To the frequency of Caverns and Openings, by whatever name de-
signated, I ascribe many of the inequalities which vary the surface of
the earth ; such openings, I conceive, produce phenomena sometimes
of Subsidence, sometimes of Elevation. I cannot entertain a doubt,
that many of the tilts and contortions of strata usually ascribed to Sou-
levemcnt, have been occasioned solely by want of adequate support.

The D.ichy of Finland exhibits an endless series of lakes filling up
the hollows of a granitic surface. Let me be allowed a similar series
of subterranean lakes occupying similar basins beneath the level of the
Baltic, and receiving, by means of Fissures extending up to the sum-
mits of the Scandinavian chain, a continual supply of water which has
no outlet ; in other words, let me be allowed the use of hydrostatic
pressure ; and without having recourse to central heat or secular re-
frigeration, I think I shall be able to account, without difficulty, not by
a general and uniform Rising, but by a number of unequal and partial
Risings, for the phenomena observed along the shores of the Baltic.

Steam is often referred to as capable of producing the same result,
nor will I deny that it might do so under favourable circumstances ;
but I apprehend Steam rarely does act in nature under such circum-
stances ; for its existence depends on the access of heat, and its force
on close confinement, contingencies not very likely to occur in the
porous and fissured strata of the earth. Any of the various Gases, if
compressed, might also become agents of elevation, but only under
the same conditions as steam.

I have reserved for the last the popular theory which accounts for
Elevation by the forcible Inroad of igneous rocks into sedimentary.

To put this theory to the test, it is natural to inquire, what igneous
rocks are. My answer is, whatever geological speculators think proper
to call so. The late Professor Dugald Stewart cautioned us strongly,
though, alas ! in vain, to avoid the language of theory. Appearances,
he observes, " should always be described in terms which involve no
" opinion as to their causes. These are the objects of separate ex-
" amination, and will be best understood if the facts are given fairly,

• In 1783, a submarine Volcano off the coast of Iceland ejected so much
pumice that the ocean was covered to a distance of 150 miles, and Shipa
were considerably impeded in their course.

Geological Society, 67

" without any dependence on what should yet be considered as nn-
V known j this rule is very essential where the facts are in a certain
" degree complicated."

In dealing out to rocks the appellation of igneous, some geologists
are more liberal than others. I have not time to enumerate the va-
rious rocks which enjoy this title, still less to investigate their respec-
tive claims to retain it. I will therefore content myself with observing,
that in the scantiest catalogue they are many in number, and con-
sequently, if ejected in a state of fusion, must have been ejected from
different reservoirs and cauldrons, not from a central cauldron.

That any rock whatever was originally igneous, is a gratuitous as-
sumption. Lavas themselves may be, and probably are, in very many
cases, Rocks not originally igneous, but Rocks which have been ex-
posed at one time or other to the action of fire.

Granite is one of the rocks most usually considered as an Agent in
Elevation, for what reason I am at a loss to discover. Solid Granite
has no inherent principle of motion ; if it move, it can only be by vir-
tue of the impulsion it has received from some other body, not in con-
sequence of its igneous origin or its want of stratification. The dis-
turbances of strata that adjoin granite are not more constant, nor more
striking nor more extensive than those of strata far remote from it, as
for instance, the limestone shales of Derbyshire or the coal-beds of
Liege. Granite veins are too small to raise mountains, and the changes
or anomalies that take place at the junction of granite with other
rocks, whatever else they may prove, appear to me to have no bear-
ing on the question of Elevation, On the other hand, the arguments
adduced against the doctrine that Granite while fluid has been forcibly
injected from beneath into its present position, are to my mind con-
clusive ; especially that which is founded on the frequent transition
which takes place from Granite to the rocks that adjoin it. We find a
continuous series from Granite through Gneiss and Mica slate to Clay-
slates and the Fossiliferous Slates j and it is not possible to stop at any
point of this progress, and to say in which direction the tendency is
strongest. If the gradation were single, the difficulty would be great,
but what shall we say to a repetition of such gradations? In Mr.
Weaver's paper on the East of Ireland, two detailed sections are
given, in one of which, more than six layers of Granite alternate with
as many of Mica slate, and in the other five alternations of the same
kind occur, the rocks in each instance forming bands from three to
seventy fathoms in thickness.

The reliance which some authors place on Granite and other un-
stratified rocks, as Agents of Elevation, is to me very extraordinary;
let one instance suffice. At Castrogiovanni in Sicily, the Pleiocene
Beds attain an altitude of three thousand feet j hence it has been in-
ferred, that since these beds were deposited, there has been formed and
introduced into the beds subjacent, a body of Granite, Sienite, Porphyry
or other crystalline and unsiratified Rocks three thousand feet in thick-
ness. This supposition is said to be necessary, but since I do not see
the necessity, I will venture another supposition, viz. that Etna has
not risen to the height of ten thousand feet without occasioning large

K2

68 Geological Society.

cavities in its neighbourhood, some of them submarine; that Castro-
giovanni is situate over one of these j that the Pleiocene strata have
closed the cavity and rendered it water-tight, except on the side of
Etna ; from whose lofty flanks and cloud-capped crater the caverns
beneath are regularly supplied by fissures with rain-water and melted
snow. Let the author grant me so much, — 1 ask no more. The
hydrostatic paradox has tripped up the hills of the geological one,
and I behold my Pleiocene beds mounted at once on a pedestal three
thousand feet high, and capable of still further proa otion.

If the explanation here offered meets the case of Castrogiovanni, it
will equally account for the height of the tertiary beds in different
parts of the Val di Noto, and for similar phenomena in every country
which is or has been formerly the site of volcanic eruptions.

To the appearances on the Gulf of St. Lawrence, described by
Captain Bayheld, 1 have already adverted.

My Predecessor directed your attention last year to the existence
in the Morea of four or five distinct Ranges of ancient Sea cliffs,
marked at different levels in the limestone escarpments by lithodo-
nious perforations, lines of littoral and sea-worn caverns, and other
striking proofs of former tidal action. Similar Terraces have been ob-
served in Sicily, in Chili, in the Gulf of St. Lawrence and various other
places. At Uddevalla in Sweden, are ancient Beaches with shells of
living species, two hundred feet above the level of the Baltic, a height
strikingly disproportionate to the very moderate Rise ascertained to
have taken place in other parts of the Scandinavian coast : many ex-
amples of similar phenomena have been found in Great Britain. It
would be rash to offer a solution of these phenomena in the gross.
Every individual case deserves separate examination. All I undertake
at present is to put a new key into the hands of the decipherer.

It was my intention on commencing this address to have discussed
at some lengrh the theory of M. Elie de Beaumont, but there is not
time now to do it justice. He belongs to that class of authors whose
opinions, right or wrong, always instruct me. There is no part of his
theory which does not evince thought and diligence, a habit of cor-
rect observation and an enlarged mind. In some respects I differ
from him, and it will not be difficult to infer from what I have already
said, wherein the difference consists. Should these observations
engage his notice, 1 would beg him to consider whether the distur-
bances in the Alps and elsewhere have not been generalized rather
more than they will bear, whether the tilts and upliftings may not
have taken place bit by bit at various epochs, and whether, if the se-
cular Refrigeration of the Globe cannot be established, and Central Heat
be an Ignis fat uus, his attention may not be usefully directed to more
partial but better authenticated sources of disturbance and elevation.

Allow me, in conclusion, to say a few words upon a subject in con-
nexion with which my name has of late been brought forward much
more prominently than I could have desired; — I mean Diluvial Action.

Some fourteen years ago I advanced an opinion, founded alto»
gether upon physical and geological considerations, that the entire
earth had, at an unknown period, (as far as that word implies any

Geological Society. 69

determinate portion of time,) been covered by one general but tem-
porary Deluge. The opinion was not hastily formed. My reasoning
rested on the facts which had then come before me. My acquaintance
with physical and geological nature is now extended j and that more
extended acquaintance would be entirely wasted upon me, if the
opinions which it will no longer allow me to retain, it did not also
induce me to rectify. New data have flowed in, and with the frank-
ness of one of my predecessors, I also now read my recantation.

The varied and accurate researches which have been instituted of
late years throughout and far beyond the limits of Europe, all tend to
this conclusion, that the geological schools of Paris, Freyberg and
London have been accustomed to rate too low the various forces
which are still modifying, and always have modified, the external
form of the earth. What the value of those forces may be in each
case, or what their relative value, will continue for many years a
subject of discussion j but that their aggregate effect greatly sur-
passes all our early estimates, is I believe incontestably established.
To Mr. Lyell is eminently due the merit of having awakened us to a
sense of our error in this respect. The vast mass of evidence
which he has brought together, in illustration of what may be called
Diurnal Geology, convinces me that if, five thousand years ago, a
Deluge did sweep over the entire globe, its traces can no longer be
distinguished from more modern and local disturbances. The first
sight of those comparatively recent assemblages of strata, which he
designates the Eocene, Meiocene and Pleiocene Formations, (unknown
but a few years ago, though diffused as extensively as many which
were then honoured with the title of universal,) shows the extreme
difficulty of distinguishing their detritus from what we have been
accustomed to esteem Diluvium. The Fossil Contents of these for-
mations strongly confirm this argument. M. Deshayes has shown
that they belong to a series unbroken by any great intervals, and
that, if they be divided from the secondary strata, the chasm can
have no relation to any such event as is called The Flood.

Further, the elephants and other animals once supposed to be ex-
clusively Diluvial, are now admitted to be referrible to two or three
distinct epochs ; and it is highly probable that the blocks of the Jura
Mountains, of the North of Germany, of the North of Italy, of Cum-
berland, Westmorland, &c, are not the waifs and strays of one, but
of several successive Inundations.

It is, Gentlemen, a well-known rule of such institutions as ours,
that the "Authors alone are responsible for the facts and opinions
contained in their respective productions." Under that feeling have
I spoken on the present occasion, and having freely set before you
what has occurred to me on some points of general interest to our
science at this time, I think it my duty, in concluding this address,
to disclaim and deprecate any attempt to connect what I have here
expressed with the general sentiments of the Geological Society. The
opinions I have uttered are my own, and I should be sorry that
more importance should be attached to them than they intrinsically
deserve, from the accident of their having been delivered from this

70 Linnccan Society.

Chair. Had not the whole responsibility fallen on myself, 1 should
have hesitated, or perhaps altogether forborne to bring before you
Opinions, several of which I know are litile in accordance with those
of some of the most distinguished members of our association.

LINNJEAN SOCIETY.

June 3. — A Paper was read entitled, " On certain Deviations from
the ordinary Structure in Telopea speciocissima. By Mr. David Don,
Libr. L.S."

In a large proportion of the Protectees, Mr. Don observes, includ-
ing Telopea, the filaments are firmly united along their whole length
to the inner surface of the foliola of the perianthium, which apparently
bearing the anthers in their concave apices, look as if they constituted
but a single series of organs, performing the double functions of sta-
mina and perianthium. In a spike, however, of Telopea speciocissima ,
which blossomed at Mr. Knight's Nursery, in May 1833, Mr. Don
found a number of flowers in which some of the filaments were en-
tirely free, and with the anthers more developed than are met with in
the ordinary state j a circumstance which may have arisen from the
oblique direction given to the stamen in a very early stage of the
flower, (at which, in ordinary cases, the cohesion most probably takes
place,) and thus, in this instance, preventing cohesion from taking
place between it and the opposite leaf of the perianthium. The pis-
tillum of this plant presents a beautiful example of adaptation. As the
leaves of the perianthium approximate closely at the base,— being
there so narrow as to have prevented the development of the ova-
rium, had it been sessile, — we find it elevated on a stalk, so as to place
it in the widest part of the tube formed by the leaves of the perianthium,
and, at the same time, to raise the stigma on a level with the anthers,
the ovarium appearing as if situated in the middle of the style. After
some further remarks on the structure of the pistillum, the author con-
cludes by showing that the figure of Telopea speciocissima in * Exotic
Botany' is very faulty, the position of the flowers with respect to the
axis of the spike being entirely reversed.

An addendum to Mr. Thompson's paper was also read, containing
a notice of two specimens of the Noddy, Sterna stolida, Linn.,
which were shot, a few years since, at sea, between the Tusker
lighthouse off the coast of Wexford, and the Bay of Dublin. Both
are in mature plumage ; one of them is now preserved in the collec-
tion of Thomas W. Warren, Esq., of Dublin, and the other in that of
W. Massey, Esq., of the Pigeon House, in the same city, who ori-
ginally received both specimens from the captain of the vessel on
board which they had been killed.

June 17. — A Paper was read "On the Female Flower and Fruit
of Rafflesia, with observations on its affinities, and on the structure
of Hydnora" By Robert Brown, Esq., V.P.L.S.

The author's principal object in this paper is to complete his ac-
count of Rafflesia Amoldi, the male flower of which he described in
a former communication, published in the 1 3th volume of the Society's

Linnccan Society. 7i

Transactions ; and, in connexion with the question of its place in a
natural arrangement, he introduces a more detailed description and
figures of Hydnora africana, than have hitherto been given. The
drawings of Rafflesia which accompany the paper are by Francis Bauer,
Esq., and those of Hydnora by the late Mr. Ferdinand Bauer.

From a comparison of Rafflesia with Hydnora and Cytinus, he is
confirmed in the opinion expressed in his former paper, but founded
on less satisfactory evidence, that these three genera, (to which
Brugmansia of Blume is now to be added,) notwithstanding several
remarkable peculiarities in each, may all be referred to the same na-
tural family j and this family, named by him Rafflesiaceae, he continues
to regard as being most nearly allied to Asarinae.

He does not, however, admit an arrangement lately proposed by
M. Endlicher, and adopted by Mr. Lindley, by whom these genera
are included in the same natural class with Balanoplwrea of Richard j
an approximation founded on their agreement in the structure of Em-
bryo, and on the assumed absence of spiral vessels. On this subject
he remarks, that in having a homogeneous or acotyledonous Embryo,
they essentially accord, not only with many other plants, parasitical on
roots, which it has never been proposed to unite with them, as Oro-
banche, &c, but also with Orchidese, their association with which
would be stiil more paradoxical. And with respect to the supposed
peculiarity in their vascular structure, he states that he has found
spiral vessels not only in Rafflesia, (in which he had formerly denied
their existence,) and in Hydnora and Cytinus, but likewise in all the
Balanophorese examined by him, particularly Cynomorium and He-
losis, as Dr. von Martius had long since done in Langsdorfia, and
Professor Meyer very recently in Hydnora.

In his observations on the ovulum of Rafflesia, he gives a view of
its early stages of development, and which he extends to Phsenoga-
mous plants generally, in some respects different from that taken by
M. Mirbel, who considers the nucleus of the ovulum, in its earliest
state, as inclosed in its coats, which gradually open until they have
attained their maximum of expansion, when they again contract
around the nucleus, and, at the same time, by elongating, completely
inclose it. Mr. Brown, on the other hand, regards the earliest stage of
the nucleus as merely a contraction taking place in the apex of a preex-
isting papilla, whose surface, as well as substance, is originally uniform,
and that its coats are of subsequent formation, each coat consisting, at
first, merely of an annular thickening at the base of the nucleus,
which, by gradual elongation, it entirely covers before impregnation
takes place.

But this mode of development of the ovulum, he remarks, though
very general, is not without exception ; for in many, perhaps in all,
Asclepiadeae and Apocinese, the ovulum continues a uniform cellular
tissue, exhibiting no distinction of parts until after the application of
the pollen tube to a definite part of its surface, when an internal se-
paration or included nucleus first becomes visible.

72 Zoological Society,

ZOOLOGICAL SOCIETY.

February 25. — A letter was read, addressed to the Secretary
by M. W. Bojer, Corr. Memb. Z.S., and dated Mauritius, Nov. 15,
1833. It referred principally to the animal from Madagascar,
which was transmitted in the spring of last year to the Society
by the late Mr. Telfair, and which was brought by Mr. Bennett
on April 9, 1833, under the notice of the Society as the type of
a new genus, for which he proposed the name of Cryptoprocta,
on account of its possessing an anal pouch, and being thereby
distinguishable from Paradoxurus, F. Cuv. One of the habits of
the Cryptoproctaferox indicated, during the life of the animal, the
existence of this pouch : when violently enraged, and it was apt to
become exceedingly ferocious on the sight of a morsel of flesh, "it
frequently gratified the persons present with, not an odoriferous,
but a most disagreeable smell, very like that of Mephitis." Other
particulars were contained in the letter, which are given in the
' Proceedings.'

The reading was commenced of a Paper, entitled " Descriptions
of New Species of Calyptrceidce : by W. J. Broderip, Esq."; and
the Shells described in it, chiefly obtained from the collection of
Mr. Cuming, were exhibited.

Mr. Owen read a Paper "On the Anatomy of the Calyptrceidce:''
After referring to the account given by Cuvier of the anatomy of
Crepidula, to that by M. Deshayes of Calyptrcea, and to M. Lesson's
of Crepipatella, as elucidating the general plan of organization in
this family, he proceeds to describe the structure of Calypeopsis.
An abstract of the paper is given in the ' Proceedings.'

Numerous specimens were exhibited of Birds collected in North
America, principally in the United States, by George Folliott, Esq.,
and presented by him to the Society. At the request of the Chair-
man, Mr. Gould brought them severally under the notice of the
Meeting. His principal object being to illustrate, so far as these
birds were concerned, the geographical distribution of allied or
identical species, he directed his observations chiefly to the deter-
mination of those North American Birds which seemed to him to be
referrible to European species, and of those which, having been
generally considered as identical with European, appeared, on di-
rect comparison, to present differences in form and colouring.

The common Turnstone of Europe, Strepsilas collaris, Temm.,
appears to be not only identical with the Turnstone of North Ame-
rica, but to be spread, without any tangible variation, over almost
every portion of the globe. The Sanderling, Calidris arenaria,Temm ,
and the Knot, Tringa Canutus, Linn., are also identical in both
continents ; as is the great volute Heron or Egret, Ardea Egretta,
Temm. The common Tern or Sea-Swallow of England, Sterna
Hirundo, Linn., occurs equally in North America. The common
Crow, Corvus Corone, Linn., is also identical in both continents.

With respect to the Whimbrel, Numenius phceopus, Temm., and
the little Sandpiper, Tringa Temminckii, Mr. Gould stated himself
to be unable to determine as to their identity without the compari-

Zoological Society, 73

son of more specimens from America than he had yet been able to
obtain for the purpose of examination.

The Cross-bill of North America Mr. Gould showed to be very
distinct from that of Europe, the Loxia curvirostra, Linn. ; it is
one third less in all its proportions, and is somewhat less brilliant in
colouring. The Ring Dottrel of North America is also specifically
distinct from that of Europe, the Charadrius Hiaticula, Linn. ; in-
dependently of differences in admeasurement, its semipalmated foot
will always serve to distinguish it.

In addition to the Birds that have been already mentioned, Mr.
Folliott's collection contained a series of the Sylviadce of the United
States, several Fly-catchers, the Orphea rufa, &c, &c.

Mr. Gray exhibited specimens of the shelly covering of a Radiated
animal, allied to the Echinidce and the Asteriida, which he regarded
as the type of a new genus, and for which he proposed the name
of

Ganymeda.

Corpus hemisphaericum, depressum ; depressione dorsi centrali
quadrangulari.

Os inferum, centrale.

Anus nullus.

Ambulacra nulla.

"The body is hemispherical, depressed, thin, chalky and hollow.

" The back is rounded, rather depressed, flattened behind, with a
rather sunk quadrangular central space.

" The sides are covered with sunken angular cavities with a small
round ring, having an oblong transverse subcentral hole in their
base.

" The under side is small, rather concave, with five slight sloping
elevations from the angles of the mouth to the angles of the rather
pentagonal margin. The edge is simple.

" The mouth is central. The vent none.

" The cavity is simple.

" The parietes are thin and minutely dotted, and the centre of
the dorsal disc is pellucid.

" This genus is very nearly allied to the fossil described by Dr.
Goldfuss in his beautiful work on Petrifactions, under the name of
Glenotremites paradoxus (tab. 49. f. 9. and t.51. f. 1.), with which it
agrees in external appearance and form, in the possession of
a sunken space on its upper surface, and in having only a single in-
ferior pentagonal mouth. It differs from Glenotremites by being un-
furnished with ambidacra running from the angle of the mouth to
the margin, by being unprovided with conical cavities between those
near the mouth, and by having in the flattened disc on the back a
central quadrangular impression instead of the pentagonal star of
that genus.

" Dr. Goldfuss describes the glenoid cavities on the surface as
giving attachment to spines similar to those of the Turban Echini,
(Cidaris, Lam.), and states that the under surface is covered with very
small tubercles to which he believes spines were attached. The

third Series. Vol. 5. No. 25. July 1834. L

74 Royal Institution.

cavities on the surface of Ganymeda and the pits in them have very-
much the form of those figured hy Dr. Goldfuss in his fossil, but I
cannot regard them as being fitted for the attachment of spines :
they have much more resemblance to the mouths of cells. So great,
indeed, is this resemblance, that I entertained doubts whether the
whole mass might not be a congeries of cells like the Lunulites,
rather than the case of a single body, until I considered that it was
impossible, from its form, that it could increase in size with the
growth of the animal, and that its exceeding regularity proved that
it must be the formation of a single creature.

" I am induced to consider these two genera, though differing in
the above-stated particulars, as forming a family or order between
the Echinida and the Asteriidce; allied to the latter in having only
a single opening to the digestive canal, and agreeing with the former
in form and consistence, but differing from it in not being composed
of many plates.

" I only know two specimens of this genus, which I believe were
found on the coast of Kent, as I discovered them mixed with a quan-
tity of Discopora Patina which I collected several years ago from
Jiici and shells on that coast. The specimens are i of an inch in
diameter.

"I propose to call the species Ganymeda pulchella."

FRIDAY-EVENING PROCEEDINGS AT THE ROYAL INSTITUTION
OF GREAT BRITAIN.

April 11. — Mr. Faraday on the definite action of Electricity. — This
was an experimental exposition of a part of his seventh series of Re-
searches, fyc, which has been reported at p. 293 of our last volume.

April 18. — No meeting, in consequence of the burial of Mr. Fuller.
This gentleman had, in the foundation of funds and the endowment of
Professorships, appropriated no less a sum than £10,000 to the ser-
vice of science and the welfare of the Royal Institution.

April 25. — Mr. Davidson on the pyramids of Egypt, illustrated from
his personal examination, and by models from measurements and
drawings made on the spot.

May 2. — Dr. Lardner on Babbage's calculating machinery, illus-
trated by numerous drawings and models.

May 9. — Dr. Dalton. Review of his scientific life, and especially of
the development of the atomic theory.

May 16. — Mr. Cowper. Illustrations of recent improvements in
Calico-printing.

May 23. — Dr. Williams on a new law of combustion. — This was
the matter of a Paper read at the Royal Society, which has been re-
ported p. 440 of our last volume.

May 30. — Dr. Lardner on Babbage's mechanical notation.

June 6. — Dr. Grant on the development of the vertebral column
in the animal kingdom.

June 13. — Mr. Faraday on new applications of the distilled pro-
ducts of caoutchouc or Indian rubber. — Conclusion of the Season.

L -5 ]

XI. Reviews^ and Notices respecting New Booh.

An Inaugural Lecture on the Study of Botany, read in the Library of
the Botanic Garden of Oxford. By Charles Daubeny, M.D.,F.R.S.,
Professor of Chemistry and Botany in the University of Oxford.
1834.

THE two Universities of this country have exhibited in succession
what would elsewhere be considered an anomaly or abuse, — a
professorial chair continuing to be held by an individual who gave no
lectures. That such a circumstance could be allowed, can only be
accounted for by conceiving a general indifference to exist in regard
to subjects on which these Professors had been appointed to lecture.
That botany should be the branch of science and education so neg-
lected must seem strange to every one acquainted with what botany
really and truly is, while, in respect to others, the neglect is as easily
accounted for as it is merited. That a different fate in both Univer-
sities now awaits it, we have no hesitation in avowing our belief. If
asked on what grounds we found this expectation, we reply, on the
different view which is taken of botany and its objects, and the dif-
ferent method pursued in teaching it. The effects of this change have
begun to show themselves at Cambridge ; and now, a voice having
proceeded from the botanical wilderness at Oxford, every one inter-
ested in the progress of the science must feel a desire to know what
sounds it will utter, — whether the uninviting language of its prede-
cessors, or the attractive strains of sound reasoning and the inductive
philosophy. Fortunately, the new Professor has furnished us with a do-
cument,— a confession of faith, — from which we may learn his opinions
and views. This introductory lecture gives, as all proper introductory
lectures should do, an outline of the plan to be pursued in teaching
the science, the details of which will be supplied in the subsequent
ones, ail of these being a continued comment on the first. The fa-
culties of mind necessary to form a botanist are stated at the com-
mencement, from which it will be seen that Dr. Daubeny, very cor-
rectly, considers him a botanist whose mind is imbued with the great
principles, by means of which plants can be collected into natural
groups, and who strives to discover the general relation in which these
groups stand towards each other, — in short, who labours to construct
and perfect a method, " where the very place which a plant occupies
in it shall, in a manner, announce its most prominent characters, the
qualities it may possess, and its affinities with others." This declara-
tion of the Professor of his intention to explain the principles of the
natural arrangement of plants has given us sincere gratification,
but which suffers some diminution from perceiving that some of the
old leaven lurks in his mind, and that he casts a lingering look behind
at the fading glories of the artificial system, the nature of which, and
its use as a dictionary, he means first to explain. Now, we are of
opinion that the juste milieu plan will not be found to answer in bo-
tany any more than it does in politics. We do not know what is the

L2

76 Prof. Daubeny's Inaugural Lecture.

mental calibre of those whom the Professor expects habitually to ad-
dress j but, if it be greater than that of children or mere boys, we
would proceed directly to the point which it is avowed is the ultimate
one — to which, indeed, all have recourse at last, if they continue the
practical investigation of plants.

We hold the pertinacious attachment to the artificial system to be
the cause of the low degree of estimation in which botanical science
is, therefore deservedly, held in this country. If we are right in this
opinion, it is certainly greatly to be regretted, that that which was
formerly dignified with the name of Botany should yet linger in our
schools, or that any should be found to teach it, since there has arisen
in its stead a science which is beautiful, philosophical, and capable of
the most varied and useful applications, — capable of being applied to
medicine, horticulture, to entomology, chemistry, and, above all, to
climatology, and, consequently, to geology. The method of Jussieu
does for the Vegetable Kingdom, that which the method of Macleay
does for the Animal, viz. by putting us in possession of a single fact,
or a few facts, it confers upon us the power of inferring many more,
relating not only to the structure of the plants, but to the juices circu-
lating in the vessels, and the products elaborated therefrom. If some-
thing more than the name of a plant be comprehended in botanical
arrangements, let us imitate the example of Linnaeus, who, conscious
of the inadequacy of his artificial system to serve the cause of genuine
botany, wisely abandoned it, and devoted himself to devising a natural
method, and called upon all botanists to assist in accomplishing so
desirable an object. Let us no longer cling to this system, which
has been expelled from almost every other country of Europe, — but
rather let us

Cast it, like an idle weed, away,

which cannot be suffered longer to deform the fair garden of philoso-
phic truth. The lecture before us contains abundant proofs of the
soundness of the principles of the natural method, and of the interest-
ing confirmation of those which the respective parts of plants afford.
To it we refer, and advise all who may feel any concern in the pro-
gress of botany to procure it, which will be at once productive of
pleasure to them, and of benefit to the Botanic Garden at Oxford, as
the profits arising from the sale of it are to be devoted to the improve-
ment of that, one of the earliest in this country. To aid in this ob-
ject, the Professor and many Members of the University have already
liberally contributed, and we trust that their praiseworthy example
will be extensively followed.

Oxford contains many amiable and enlightened men, well disposed
to see instruction in the natural sciences form a part of the regular
academical course of education. By the strenuous and able exer-
tions of the new Professor, these cannot fail to become more numer-
ous. We therefore wish him the success he deserves in the prosecu-
tion of his labours, and by which the cause of botany will be greatly
promoted, and its sphere of usefulness extended. %*

C 77 ]

XII. Intelligence and Miscellaneous Articles,

RECENT DISCOVERY OF BONES OF THE IGUANODON.

AN interesting specimen of this fossil reptile has been lately
discovered in the Shanklin sand formation, in the immediate
neighbourhood of Maidstone in Kent. The quarry in which these
remains occur consists of many strata, regularly alternating, of com-
pact limestone, and of sand more or less loose. Each stratum is of
the thickness of from 8 inches to 12 or 14 -, and the alternation of
the two species of beds is remarkably regular and equal.

It unfortunately happened that the blast by which these remains
were brought to light was inserted into what proved to be the centre
of this very deranged specimen, so that the whole mass containing it
was shattered into many pieces. By the great care bestowed upon
them, however, by the very intelligent proprietor of the quarry, Mr.
W. H. Bensted, nearly all the detached pieces have been collected,
and the various bones carefully cleared from the rock which forms their
matrix. These remains, together with the other fossil bodies con-
tained in the same strata, cannot fail to prove of deep interest in a
geological point of view. That both the sand and the limestone are
marine formations there can be no doubt, for though wood and vege-
table substances are not uncommon in these beds, yet the limestone
abounds in ammonites, sharks' teeth, and other sea productions, while
a small sea shell was also found fixed upon one of the bones of the
iguanodon. These bones (which have been recognised on the spot as
belonging to this species, by Mr. Mantell,) consist of two femora, a
tibia, fibula, 15 vertebrae, 2 clavicles, 2 claws, 2 teeth, some ribs,
&c. One of the femora is 32 inches long, and its position with
respect to the mineral beds inclosing it is worthy of particular atten-
tion, as throwing much light upon the manner of the deposition of
these beds. It stands nearly in a vertical position as regards the
strata, which are nearly horizontal j and it projects from the solid
limestone bed, which embraces its lower extremity, and passes nearly
through the superincumbent bed of sandstone. Here is distinct
proof that these two beds, now so different in their consistency, were,
in the one case, loose sand, and in the other, tenacious mud, at the
period when this shattered and decomposing body sunk to the bottom
of the st a, and became covered up by an abundant deposition. Nor
can we doubt that this deposition took place most rapidly, as this long
bone must then have been in a loose and moveable condition, (proba-
bly only attached to the other bones by strong integuments,) and
could not long have retained an upright position. But if this infer-
ence be just with respect to the nature of the deposition of those
two beds, we cannot avoid coming to the very same conclusion with
regard to all the other beds of the series, of a nature precisely similar,
and extending to a depth of many feet, in the quarry.

We have thus, in this instance, proof of marine origin, and of a ra-
pidity of deposition greater than we can well calculate upon, in exist.

*78 Intelligence and Miscellaneous Articles.

ing marine action. This proof leads to the same conclusion (though
on a smaller scale), as the vertical stems of large trees in the coal and
other secondary strata, intersecting many distinct beds : and this
more than natural rapidity of deposition, which is not yet acknow-
ledged by geologists in general, cannot fail soon to attract attention,
and to exercise a powerful influence on many opinions at present
generally received, which are entirely opposed to it.

G. F.
June 10, 1834.

MURIATIC ACID IN FLUOR SPARS.

M. Kersten states that in examining the results of the decomposi-
tion of certain minerals in which he found that chlorine and fluorine
frequently replaced each other, he suspected that fluor spars might
probably contain chlorine or muriatic acid, and this idea was con-
firmed by finding small quantities of it in several varieties of the blue
fluor spar of Marienberg, and in some of those of Freyberg. — Ann. de
Chim. et de Phys., torn. liii. p. 324.

POLYSPHERITE, OR BROWN PHOSPHATE OF LEAD.

This mineral was found in 1830 near Freyberg: it consists of
globules and isolated drops placed upon each other, in the interior of
which a great quantity of concentric radii are visible. Its lustre is
greasy : its colour passes from clove brown to Isabella yellow. Its
fracture is radiated : its hardness is equal to that of calcareous spar,
and its density, according to M. Breithaupt, is 6-092.

M. Kersten found it to consist of

Oxide of lead 72- 1 7 or Chloride of lead 1 0838

Lime 6*47 — Fluoride of calcium . . 1 *094

Muriatic acid 2*00 — Subphosphate of lead . 77*015

Phosphoric and muriatic 1 , 9.36 _ Subphosphate of lime . 1 1 -053
acids and loss J r r

100 100

Ibid.

NEW RADICAL ANALOGOUS TO CYANOGEN.

M. Liebig states that he has found a new radical composed of
3 atoms of carbon and 5 of azote ; it is a pulverulent body, insoluble
in water, and decomposes at a red heat, into azote and pure cyanogen,
in the proportion of 1 : 3. It combines with potassium, and furnishes,
by combining with acids and alkalies, a series of new combinations.
One of these bodies treated with nitric acid gives ammonia, and a new
acid, which is soluble in water, and crystallizes on cooling in plates
of a brilliant metallic appearance. This acid is perfectly similar in
composition to cyanuric acid, but the weight of its atom is double ;
its formula is C6 N6 H6 Ofi. By distillation hydrated cyanic acid, &c,
are obtained. — Ann. de Chim. et de Phys., torn. liv. p. 252.

Intelligence and Miscellaneous Articles. 79

ON SUBOXIDE OF LEAD AND PROTOXIDE OF TIN. BY M. BOUS-

S1NOAULT.

By subjecting oxalate of lead to dry distillation, M. Dulong ob-
tained a black powdery residue, which he considered as lead of a low
degree of oxidation. M. Berzelius is of opinion that this new oxide
is produced when metallic lead is exposed to the atmosphere. The
existence of this suboxide is not, however, admitted by all chemists,
and its composition has not been determined.

To determine the question M. Boussingault prepared suboxide of
lead, by decomposing the oxalate in a small glass retort. To obtain
it pure the body of the retort must be kept at a low red heat j at a
higher temperature some globules of lead are produced, and the glass
is attacked.

When the disengagement of gas has ceased, the retort must be al-
lowed to cool without access of air. This is easily managed by adapt-
ing a long tube to the retort and plunging it into mercury.

The suboxide of lead is of a very dark gray colour, almost black.
When heated below the fusing point of lead, it is converted into
oxide. Sulphuric, muriatic, and acetic acids attack it, especially when
heated ; oxide of lead is formed, which combines with the acids, and
metallic lead separates.

When mixed with water and exposed to the air, the suboxide is
quickly converted into carbonate of lead ; under water, and without
the contact of the air, it suffers no change. Mercury rubbed with the
suboxide under water does not dissolve lead. This experiment seems
to prove that suboxide is not, as has been supposed, a mere mixture
of lead and oxide.

In order to determine the composition of this suboxide it was con-
verted into oxide, and the absorption of oxygen noted : this was ef-
fected by heating it in a cupel to nearly a red heat. In two experiments
100 parts of suboxide became 103*6 of oxide, containing 7*2 of oxygen;
and as the oxygen which combined with the suboxide during calci-
nation amounted to 36, it is evident that in the suboxide the lead is
combined with precisely half as much oxygen as exists in the oxide.
The suboxide may therefore be considered as constituted of 1 atom
of oxygen -f 2 atoms of lead.

Oxalate of tin prepared by pouring oxalic acid into protacetate of
tin, yielded by distillation water, oxide of carbon, carbonic acid, and
empyreumatic oil. The residue was protoxide of tin of a bright
brown colour. — Ibid., p. 264.

SCIENTIFIC BOOKS.

Researches in Theoretical Geology. By H. T. De la Beche, F.R.S.,
V.P.G.S.

Outline of the Geology of the Neighbourhood of Cheltenham. By
R. I. Murchison, F.R.S., V.P.G.S.

Report of the British Association for the Advancement of Science
at Cambridge in 1833.

Origines Biblicce • or Researches in Primaeval History. By Charles
T. Beke.

I

4

4

a

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1

London.— May 1. Rain. 2. Fine. 3. Very
fine : clear. 4. Sultry : rain at night.
5. Heavy rain. 6, 7. Very fine. 8. Foggy :
fine. 9. Heavy dew : overcast. 10. Fine:
11. Fine: lightning at night. 12. Slight rain:
cloudy and fine: rain. 13. Heavy showers.
14—16. Fine. 1 7. Rain. 1 8. Cloudy : clear
and cold at night. 19—21. Very fine.
22—31. Fine : but very dry with easterly
winds.-* The dry state of the atmosphere in
the latter part of the month was unfavourable
to most kinds of vegetation. No rain having
fallen after the 17th, the supply of moisture
in the soil became much exhausted, especially
as only a moderate quantity fell in the pre-
vious part of the month; and in the two pre-
ceding, the amount was not the usual average
for one. It may be remarked, that the pre-
valence of S.W. winds, and the concomitant
superabundance of rain in December and
January last, appears to have been since ba-
lanced by a reaction of as long duration from
the opposite quarter, and with a deficiency of
rain as much below the average quantity, as
this, in the former case, was exceeded.

Boston. — May 1. Cloudy: rain early am.
2. Fine. 3, 4. Cloudy. 5. Rain. 6, 7. Fine.
8, 9. Cloudy. 10, 11. Fine. 12. Cloudy.
13. Rain. 14. Cloudy. 15. Cloudy : rain
early a.m. 16. Fine. 17. Fine : rain p.m.
18. Cloudy. 19—24. Fine. 25. Cloudy.
26—31. Fine.

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THE

LONDON and EDINBURGH
PHILOSOPHICAL MAGAZINE

; AND

JOURNAL OF SCIENCE.

♦-

[THIRD SERIES.]

AUGUST 1834.

XIII. Experiments and Observations on the Action of Water
and Air on Lead. By Captain Philip Yorke.*

1. A LTHOUGH the action of water on lead has at
—■ different times been noticed by chemical and other
writers, yet I venture to think that the experiments I have to
offer comprehend some new facts, and some which may assist
us in correcting views deduced from the results of previous
experimenters.

2. My experiments originated in the examination of some
spring water which had flowed through somewhat more than
100 yards of leaden pipe. When this water, fresh drawn from
the cistern, was tested by a solution of sulphuretted hydrogen
gas, it gave a clear brown tint. The quantity of oxide of lead
estimated by the sulphuret obtained from 14^ measured ounces
amounted to ^2nontn* When it had stood two or three days
in an open vessel, it no longer gave the brown tint when
tested, but some white particles suspended in the liquid were
blackened.

3. This circumstance called my attention to some results
obtained by Guy ton de Morveau, quoted by Berzeliusf, viz.
" that oxide of lead is soluble in pure water, but insoluble in
water which contains the least trace of salt. If distilled water
is poured into a vessel of lead, and is left for some time, the
lead is attacked and the water acquires the property of exer-

* Communicated by the Author.
T Traite de Chimie, torn. iii. p. 178.
Third Series. Vol. 5. No. 26. Aug. 1834. M

82 Capt. P. Yorke's Experiments and Observations

cising a feeble alkaline action on reddened litmus paper, is
rendered brown by sulphuretted hydrogen gas, and is made
turbid by sulphuric acid."

4-. As I had not at this time seen these facts stated in any
other chemical work, I made the following experiments to
ascertain their exactness. I put some distilled water into a
glass, loosely covered so as to keep out dust, and filled a
phial fitted with a ground-glass stopper with distilled water.
I then arranged similar vessels with spring water, and into
each I put a slip of clean and fresh-cut lead. The spring water
used in this experiment I had previously ascertained to con-
tain in the gallon (of 10 pounds) 1*21 grain of the chlorides
of sodium and calcium, and 6*4? grains of carbonate of lime
held in solution by excess of carbonic acid (7^77^)-

5. The spring water used in the above experiments with
lead was tested by sulphuretted hydrogen after the lapse of
three days, three weeks, and a year respectively, but never
gave any indication of holding lead in solution. The lead ac-
quired its usual dull surface at last, and became invested near
the surface of the water with oxide of a reddish and brownish
colour, much resembling in colour, but not in thickness, that
incrusting the leaden bullets described by Mr. Faraday in the
Journal of Science, vol. xvi. p. ] 63. The lead in the distilled
water and open vessel (a) in five days was covered near the
surface of the water by fine white flaky crystals radiating from
the lead. The water when tested by sulphuretted hydrogen
gave a brown tint. The same kind of action took place in the
stopped phial (b), but much slighter. In the open vessel, at
the end of three weeks, a quantity of the white crystalline
substance had accumulated at the bottom of the glass, and a
zone of pearly crystalline flakes of the same substance had
formed on the surface of the water, adhering slightly to the
glass and to the lead. A portion of this substance was col-
lected and dried at 212°. When treated with dilute acids it
dissolved : I did not perceive any effervescence. When heated
in a glass tube it gave off a portion of water and became yel-
low.

6. The stopped phial, when examined after standing a year,
presented the following appearances. The bottom of the
phial was covered with about £ of an inch in depth of the white
crystalline substance before mentioned. The slip of lead it-
self was covered for about f rds of its length from the lower
end with brilliant laminar crystals (b) projecting from the lead
about 7Vtn °f an inch. When brushed off the lead and ex-
amined by reflected light, their colour was greenish grey, and

on the Action of Wetter and Air on Lead, 83

much resembled some brilliant varieties of mica: under the
microscope by transmitted light they were yellowish.

7. Such are the general appearances presented by the action
of water on lead. To ascertain whether any effect was produced
when access of air was entirely cut off, I filled a little retort
with distilled water, and boiled it for some time; I then intro-
duced into it some fresh-cut clear slips of lead. The beak of
the retort, which was quite full of water, was then immersed
in a basin of mercury, the surface of which was covered with
water. When this arrangement was examined after standing
three weeks, not the smallest bubble of gas was visible. The
lead was still bright, though a little whitish in places : the
water struck a very pale brown when tested by sulphuretted
hydrogen. The retort was then left open and half-filled for
a night ; a quantity of the white substance formed, and the
water gave a deep brown when tested. It is evident from this
experiment that the lead does not derive oxygen from the
water, but from the air contained in it, though, like iron in si-
milar circumstances, it is a delicate test for oxygen dissolved
in water*.

8. To obtain the products of the action of air and water
on lead in larger quantities, I filled a quart bottle about f rds
of its capacity with distilled water, which I agitated briskly
with the air, and introduced a parcel of clean cuttings of sheet
lead : white clouds appeared in a few minutes; and the bril-
liant grey crystals (b) began to be visible on the surface of
the lead after standing four days. After, standing a month,
the surface of the water was covered by a slightly coherent
stratum of the white crystalline substance, and there was also
a deposit of the same matter : the lead was covered by the
brilliant grey crystals. A quantity of these last were brushed
off the lead : they dissolved quietly in acetic acid. A portion
introduced into a bit of glass tube, closed at one end and pre-
viously counterpoised, weighed y9^ grain. When this was
heated red by a spirit-lamp, it decrepitated a little, and a very
small portion of water was condensed in the cool part of the
tube : when this was driven off, the loss was only y^ of a grain.
The substance had become yellow, but the structure was not vi-
sibly altered. In another trial no water was given off. Hence
it appears that this product was the anhydrous protoxide of
lead. But I found that besides these laminar crystals there were
many much smaller crystals adhering to the lead : when ex-
amined by the microscope they appeared colourless and semi-
transparent, having very brilliant facets. Many of them were

* See Dr. M. Hall on the Oxidation of Iron, Journal of Science, vol. vii. p. 55.

M2

84 Capt. P. Yorke's Experiments and Observations

perfect rhombic dodecahedrons, and others of the same funda-
mental form with the acute solid angles replaced by tangent
planes : they varied in diameter from about g-^th
to Ttf£otn °f an mcn* When heated, these cry-
stals become opake and orange-coloured, but
without losing their form or brilliancy of surface.
Houton Labillardiere*, it is said, obtained do-
decahedral crystals of the anhydrous protoxide as a deposit
from a solution of oxide of lead in a solution of caustic soda;
and Becquerel has obtained cubes by heating the oxide with
pure potash f.

9. Lead, as it occurs in commerce, it is well known, gene-
rally contains portions of copper and iron. I found on trial
that the lead I had used did contain those metals, (it contained
no silver,) and traces of copper could even be detected in the
grey crystals of oxide, when they were fused with borax be-
fore the blowpipe in the reducing flame. Lest the action of
water and air described should be in any way dependent on
these alloys, I attempted to procure a quantity of the metals
quite pure to repeat the experiments on.

10. Nitrate of lead was recrystallized, till the mother liquor
gave no trace of copper on the addition of carbonate of am-
monia, and the oxide resulting from the calcination of this
nitrate was reduced by black flux in a Hessian crucible. It
was then kept in fusion for some time at a low red heat in a
Wedgwood crucible to separate any carbon it might contain.
The lead thus obtained yielded, however, a very slight trace
of iron, — derived, I believe, from the action of the flux on
the Hessian crucible, — but none of copper. A bright slip of
this lead was treated with distilled water as before ; the effects
were similar : the white crystalline substance formed first, and
after about a month, the brilliant grey crystals of anhydrous
oxide were formed ; they had, perhaps, less of a green shade
of colour than those formed on common lead.

11. In a quantity of a solution of oxide of lead in lime-
water, which had been left a year in a flask stopped by a
cork, some brilliant crystalline folia had formed about ^ an
inch across, dependent by their upper edges from the surface
of the liquid ; they were very thin, flexible and elastic. By
reflected light, their colour and lustre resembled that of steel
blued by heat. They dissolved quietly in acetic acid, became
yellow when heated, and appeared identical with the crystal-
lized laminae before described — anhydrous protoxide (8).

12. A bright iron nail was driven into a clean slip of lead,

* Berzeliu*, torn. Hi. p. 178. f Ann. de Chimie, torn. li. p. 104.

on the Action of Water and Air on Lead. 85

and the combination immersed in a phial of distilled water as
before. The next day, the white crystalline substance had
formed on the lead, and some rust on the head of the nail:
the point in contact with the lead remained bright many days.
Another nail, placed in a similar phial of distilled water, for the
sake of comparison, was covered by brown hydrated oxide in
three days. When the first arrangement was examined after
standing seven months, the nail next the lead was still partly
bright: the head was covered with rust, mixed with which the
grey laminar crystals of oxide of lead and the little dodeca-
hedral crystals were scattered over the surface both of the
lead and the iron. The water when tested by sulphuretted
hydrogen gave a deep brown tint.

13. A slip of lead, which had the ordinary dull surface
which the metal acquires by exposure to the atmosphere, was
immersed in a phial of distilled water which had been agitated
with air, as in the previous experiments : the water was tested
at the end of a week by sulphuretted hydrogen, but gave no
indication of holding any lead in solution.

On the white \flaky Crystals.

14. Before I consider the nature of this substance, I should
observe, that when I made my first experiments on the sub-
ject, I was not acquainted with the researches of Dr. Christi-
son, contained in his Treatise on Poisons, p. 458 et seq.,
2nd edit., but from my own (5.), I did not doubt that De
Morveau was right in concluding that the substance in ques-
tion was a hydrate. Dr. Christison, however, maintains as
the result of his experiments that both the white crystals,
whose external character he describes much as I have done,
and the lead held in solution by the distilled water, are in
the state of carbonate. Most, then, of the experiments that
follow were made with the knowledge of Dr.Christison's pre-
vious researches, and some with the particular object of deter-
mining between G. de Morveau's and my own first opinions
on the one hand, and Dr. Christison's results on the other.

15. The substances were obtained as related (8.); the white
substance collected and dried in vacuo with sulphuric acid:
when dry it effervesced very slightly with a dilute acid. A por-
tion weighing 2*67 grains was introduced into a bent tube of
green glass closed at one end ; the open end of this was fitted in-
to another tube, both being provided with corks and previously
counterpoised : the substance was then heated red in the re-
tort tube, and some water condensed in the receiver tube ; the
tubes were then corked, and weighed when cold : the retort

86 Capt. P. Yorke's Experiments and Observation?

tube had lost *28 grain ; the water in the receiver weighed *06
grain only.

16. In another experiment, an open test tube, containing a
solution of caustic potash, was placed in the bottle with the
lead and water. The white substance in question which form-
ed was dried in vacuo as before. A quantity, equal to 1*688
grain, was introduced into a green glass tube about S\ inches
long (a), into which was fitted, by grinding, the little tube {b\
open at both ends, filled with chloride of calcium, and the
end of the tube (c), which was adapted to the end of tube

c

m^

UP

(a) by a collar of caoutchouc, introduced under a jar full of
mercury. The tube (a) was then heated : a quantity of gas was
given off", equal *42 cubic inch, of which *16 cubic inch was
absorbed by caustic potash. The tube (b) had gained -05
grain; the tube (a) weighed when cold, had lost '158 grain.
Yellow oxide remained.

17. In another experiment with the same apparatus 1*314?
grain gave off a portion of gas which was absorbed by potash,
but from an accident the quantity was not estimated. The
chloride of calcium gained *036 grain, and the tube (a) lost
•154 grain.

18. If the whole loss sustained minus the quantity of water
collected be reckoned as carbonic acid, we have as the result
of the last two experiments :

Ex. 2. Ex. 3.

Oxide of lead I' 53 1*16

Water 0*050 0*036

Carbonic acid 0*108 0*118

1*688

1*314

Ex. 1.

89*5

Or, in 100 parts, Ex. 2.

Oxide of lead 90*63

Carbonic acid 6*341

Water 2*96 J

10. These experiments are not sufficiently accordant, nor
made on large quantities enough to determine whether the

9*3

Ex.3.

88*28
8
2

:?®}ll.72{lO-5

on the Action of Water and Air on head, 87

substance thus obtained is a definite compound or a mixture;
but if 223 '4 represent two equivalents of oxide of lead, 22*1
carbonic acid, and 9 water, then a substance which should

consist of 2 Yb + C-\-Aq would contain in 100 parts,

Oxide of lead 87*9

Carbonic acid 8*6\19 ,

Water 3'5 J ~

100-
and might also be represented by {Pb + C} + {Fb + Aq}.

20. When a portion of this substance was put into a stop-
ped phial with distilled water, and the water tested after some
days by sulphuretted hydrogen, it gave a barely perceptible
brown tint.

When some of the substance slightly moistened was ex-
posed freely to the air two or three hours, it dissolved in acids
with brisk effervescence, like common carbonate of lead.

Of the Solution of Lead in distilled Water.

21. In order to show the power the aqueous solution of
oxide of lead possesses of reddening turmeric paper, it is suffi-
cient to put a single slip of fresh-cut lead into a phial of di-
stilled water which has been agitated with air, and introduce
with it a bit of turmeric paper : in two or three hours the pa-
per will be permanently reddened.

22. The liquid obtained by experiment 8, and others si-
milarly conducted, has the following properties: 1. it reddens
turmeric paper easily, and restores the blue of reddened litmus
paper ; 2. it gives a deep brown colour with a solution of sul-
phuretted hydrogen, and soon deposits a black precipitate;
3. it becomes immediately very turbid on the addition of di-
lute sulphuric acid; 4. also with a solution of carbonic acid;
5. turbid with a solution of sulphate of soda, — the effect much
increased by a drop of sulphuric acid ; 6. an equal effect with
bisulphate of potash. With a drop of a solution of iodide of
potassium, it gave a white cloud, which on the addition of a
drop of very dilute muriatic acid became orange-yellow, and
deposited a yellow precipitate of iodide of lead. With a so-
lution of common salt it immediately becomes turbid ; also
the same with the solution of sulphate of lime, containing
To\jotft of that salt ; slightly turbid with a solution of nitre.

With neutral chromate of ammonia it preserved its trans-
parency; but when a very minute quantity of acetic acid was
added, it deposited a yellow precipitate.

88 Capt. P. Yorke's Experiments and Observations

When agitated in a half- filled phial it becomes turbid. The
same effect occurs when it is boiled in a glass flask. When
left freely exposed to the air without the contact of lead, it
deposits the whole, or nearly the whole, of the oxide in the
form of the white substance before described.

23. Becquerel has shown that when solutions of lead or
manganese are decomposed by the voltaic battery, the con-
ducting wires being of platina, the peroxides of those metals
are separated at the positive pole*. I find this to be the case
with lead, whether the acetate, the nitrate, or a solution of
the oxide in lime water be employed. When the aqueous
solution of oxide of lead was thus decomposed, the conducting
wires being terminated by slips of platina foil, that at the
negative pole was slightly blackened by metallic lead, that at
the positive acquired a fine bronze yellow, and the edge of
a bit of litmus paper in contact with the foil was bleached.

24. In my first attempts to ascertain the quantity of oxide
of lead which was held in solution by distilled water, the li-
quid obtained, as is described (8.), was filtered; but the fil-
tered liquid was turbid, and when obtained clear by refiltering
it was found on testing it that it no longer contained any lead
in solution. This was repeated on a portion of liquid from
another bottle, which previously to filtering gave a deep brown
with sulphuretted hydrogen, with the same effect.

25. To obtain the quantity of oxide of lead dissolved by the
water, the rods of lead were carefully removed from the bottle,
the stopper replaced, and the liquid, when clear, drawn off by
a siphon.

1st trial; 3000 grains of such a solution evaporated with a
drop of nitric acid, converted into a sulphate, and thus
ignited, weighed '33 grain = -242 oxide.

2nd, 3000 grains evaporated with a drop of nitric acid in
a flask ; the evaporation terminated, and oxide ignited in a
platina crucible ; the oxide obtained weighed *245 grain.

3rd, 5000 grains of the solution was divided into two equal
parts : one part was reserved for a subsequent experiment;
the other, evaporated as in the last, gave *244 grain of
oxide. In the first two trials the quantity of oxide dis-
solved is about -r^utn> in the tnird Tuhv

26. It is very possible, however, that pure water is really
capable of holding a greater quantity of oxide of lead in so-
lution than has been here obtained; for it is difficult, if not
impossible, to disturb these solutions without occasioning the
deposition of part of the oxide in the form of a white powder,

* Ann. dc Chimie, torn, xliii. p. 380.

on the Action of Water and Air on Lead, 89

e. gr. the removing the rods of lead from the bottle is suffi-
cient. I cannot say from experiment whether this effect is
determined by the contact of the carbonic acid in the atmo-
sphere, and that the substance deposited is identical with
the white crystalline body already described, or from some
other cause, but am more inclined to think it should be re-
ferred to the agitation of the liquid, which causes crystalliza-
tion to take place in a nearly saturated solution.

In an experiment in which fresh distilled water was agitated
with pure oxygen gas, clean slips of lead being introduced
into it, and the phial closed by a perforated cork, through
which an open tube passed filled with fragments of slacked
lime, the liquid when examined after three weeks appeared
by the action of tests the strongest aqueous solution of
lead I had obtained ; but the white deposit at the bottom of
the phial was much scantier and less bulky, and had none
of the crystalline character previously observed. Whether
moist or after drying in vacuo, it did not present the
slightest appearance of effervescence when dissolved by di-
lute nitric acid.

27. I have before said that Dr. Christison has stated, as the
results of his experiments, that the lead dissolved by water is
in the state of carbonate. But the following experiments, I
think, show, that, in my method of experimenting at least, such
is not the case, and also that the carbonate is a much less so-
luble substance than the oxide or hydrated oxide.

28. A solution of carbonic acid was prepared by passing
the gas evolved from calcareous spar and very dilute nitric
acid into an air holder, and from that into distilled water, con-
tained in a large two-necked bottle, where the gas could be
agitated with the water under moderate pressure. In this
way a solution was obtained free from any other acid, and
which, by boiling, gave off about two thirds of its volume of
carbonic acid gas.

When this solution of carbonic acid was poured into a so-
lution of lead in distilled water, obtained as before (8.), a pre-
cipitate took place, which, however, was redissolved b}r consi-
derable excess of the solution of carbonic acid. In this, again,
solution of bicarbonate of potash caused a cloudiness.

29. Into the reserved portion of the solution from the 3rd
experiment (par. 22.) = 2500 grains by measure, a current
of carbonic acid, evolved from dilute nitric acid and calcareous
spar, was passed : this immediately caused a cloudiness, and
when the precipitate had subsided, a portion of the clear
liquid was tested by sulphuretted hydrogen, which gave a very

Third Scries. Vol. 5. No. 26. Aug. 1834. N

90 Capt. P. Yorke's Experiments and Observations

pale brown tint. The quantity of oxide actually obtained
from the precipitate by igniting and weighing it, amounted to
•132 grain, but part was lost.

30. Some pure protoxide of lead, obtained by heating the
subnitrate in a platina crucible, was put into a phial filled
with the solution of carbonic acid ; another portion of the
same oxide was put into a phial filled with distilled water :
both phials were closed by ground-glass stoppers and ce-
mented. In the distilled water a quantity of a white floccu-
lent substance formed above the yellow oxide ; in the carbonic
acid no change could be observed for some time. At the
end of a month a small quantity of a white substance could
be perceived among the oxide. When the liquids from these
arrangements were tested after the lapse of that time, the addi-
tion of sulphuretted hydrogen produced no effect in the car-
bonic acid solution ; but it immediately struck a deep brown
with the distilled water, which also reddened turmeric, and
gave a precipitate with bisulphate of potash and solution of
carbonic acid as in prior experiments with metallic lead.

31. Bright slips of lead were put into the solution of car-
bonic acid (a), and to guard against the possibility of the dif-
ference of action being owing to any other substance than the
carbonic acid, a part of the same solution was boiled for some
time to expel the acid, and similar slips of lead introduced into
it (b). The next day the liquid in (b) was milky, in (a) the
lead continued bright for more than a week ; while white cry-
stalline flakes had formed in the other, in which, in fact, the
effects were altogether similar to those obtained in previous
experiments with distilled water. The liquid from (a) gave a
barely perceptible tint on the addition of a solution of sulphu-
retted hydrogen.

On the Carbonate of Lead,

32. Carbonate of lead was prepared by precipitating a so-
lution of the subacetate by a current of carbonic acid gas.
The carbonate thus obtained was well washed with distilled
water; but when a large quantity had been used, the washings,
when tested by sulphuretted hydrogen, still indicated a minute
portion of lead to be present : further washing did not diminish
the effect. When this had arrived at the minimum, sulphuretted
hydrogen gave a pale brown tint ; and solution of bicarbonate
of potash produced a very faint milkiness after standing some
time. When the solution of carbonic acid was passed through
carbonate placed on a filter, the filtered liquid gave an im-
mediate milkiness on the addition of bicarbonate of potash,

on the Action of Water and Air on Lead. 91

and with sulphuretted hydrogen a decided brown, but not
equal in tint to that produced by distilled water which had
been three or four days in contact with lead.

Some of the same carbonate was put into a phial with the
solution of carbonic acid and another portion of the carbonate
into another phial with distilled water. When the liquids were
tested after standing two days, the carbonic acid solution gave
a brown colour, the distilled water a very pale tint.

33. To ascertain the degree of solubility of carbonate of
lead in the solution of carbonic acid, a solution of carbonate
of lead was formed by putting a quantity of carbonate of lead,
obtained as before stated, into the solution of carbonic acid in
distilled water. After standing some days the clear liquid was
drawn off for experiment (a).

Another solution was obtained by washing some good ce-
ruse on a filter, until the filtered liquid, when tested by sul-
phuretted hydrogen, gave no further diminution of tint. By
continued effusions of distilled water, the solution of carbonic
acid was then filtered through the washed carbonate, and the
liquid preserved for use (|3).

34. A standard solution of lead was then made by dis-
solving one grain of pure oxide of lead in acetic acid, and eva-
porating this to dryness at the heat of boiling water, and dis-
solving the resulting acetate in 1000 grains of distilled water.

35. When a portion of the standard solution was diluted
with about 83 parts of distilled water, the tint produced on
testing this by sulphuretted hydrogen and the solution in car-
bonic acid (a), was equal. When the standard solution was
diluted with between 50 and 60 parts of distilled water, the
tint produced on testing it and the solution (0) was equal.

36. Thus it appears that such a solution of carbonic acid as
I used is capable of holding in solution about from so^0th
to ^-g-i—gth of oxide of lead if presented to it in the state
of carbonate. These solutions immediately become turbid
when carbonate or bicarbonate of potash is added; but, with
(a) at least, no effect was produced by the action of any of
the other tests tried on the distilled water, nor is it made
turbid by agitation.

37. When clean cuttings of lead were immersed in solutions
of common salt, and sulphate of lime, in the proportions of one
part salt to one thousand parts distilled water ; in one ounce
of water with a drop of sulphuric acid ; in the spring water
(par. 5.) boiled, and the liquids tested after three weeks, no in-
dication of their holding lead in solution could be perceived.

But the power of saline bodies to prevent the action of
pure water on lead is a part of the subject which, noticed

N 2

92 Capt. P. Yorke's Experiments and Observations

by G. de Morveau, has been so much more fully investigated
by Dr. Christison that I shall not dwell further on it. Dr.
Christison found that T^r.-oo-ffth of phosphate or hydriodate of
potash was an almost perfect preventive of the action of distilled
water. This author, however, gives it as his opinion that an
unusual quantity of carbonic acid in natural water is the most
common counteracting cause which impairs the power of sa-
line bodies to protect lead, and he supports this opinion by
an experiment made with the Edinburgh water (" Poisons,"
p. 465). The few facts that I have observed which bear on this
part of the inquiry do not accord with this view of the matter,
at least so far as the dissolving power of water is concerned.

38. I mentioned in the first paragraph a spring water
which had the power of holding a portion of lead in solution;
I found also that when drawn from the spring head, and made
to act on lead, as in the before-mentioned experiments, it gave
indications in a few days of holding a minute portion of lead
dissolved.

A portion of this water was brought from the spring head
in a well stopped bottle, and examined. It remained perfectly
transparent when an excess of lime was added, and after be-
ing boiled 32 measured ounces were evaporated to dryness
in a silver crucible at a heat a little above 300°. The residue
weighed 1*75 grain: of this T6oths of a grain was soluble in
strong alcohol, and proved to be chloride of manganese with
chloride of aluminum, and the remainder sulphate of lime with
some sulphate of iron and a little silica. Both this spring and
the one mentioned rose on the same hill, which consisted of
the upper conglomerate beds of the old red sandstone, and
contained occasionally thin veins of oxide of manganese.

It is somewhat remarkable that Dr. Lambe* has attributed
the power of spring water to dissolve oxide of lead to a
" compound salt, the basis of which is manganese and iron,
with, perhaps, a little nickel." He thinks that the acid of this
salt is the muriatic, and that such a compound is diffused
through all common spring water ; but this is surely general-
izing the matter more than his or any other experiments
warrant. It seems clear, however, that he did detect manga-
nese in some of the specimens of spring water which he ex-
amined.

On the Electric Relation of Lead to Iron, fyc.

39. In the course of these researches I was led to make
some experiments on the electrical relation of lead to other

• Researches on Spring Water, p. 158 el seq.

on the Action of Water and Air on Lead. 93

metals, particularly iron, partly because it appeared that ef-
fects that have been described might be modified by the con-
tact of other metals, and partly because the tables of the elec-
tric order of metals given by different philosophers differ from
each other in the place assigned to lead. Thus in Dr. Henry's
Elements we have first Sir H. Davy's table of metals, the
liquid conductor being acid or saline solutions, and it runs
thus — zinc, iron, tin, lead, copper, each being positive to
those that follow : some pages further in the same work we
find Volta's arrangement*, which runs thus — zinc, lead, tin,
iron, copper. This also accords with Pouillet's table.

40. My experiments were made with a galvanometer having
two needles and a glass thread, as constructed by Dr. Ritchie.
The plates of the metals were 2 inches long by 1^ wide, and
retained at equal distances by fixing a slip of wood a quarter
of an inch thick between them. Copper wires were soldered
to the plates to connect them with the cups of the galvano-
meter. The liquids were contained in cylindrical earthen-
ware cups holding about 4 ounces of water.

I found that when the liquids employed were either distilled
water, spring water, solutions of neutral salts, dilute sulphuric,
muriatic or nitric acids, lime-water, or solution of caustic
potash, and the metals both bright, that lead was to iron
constantly as the zinc to copper in the common voltaic ar-
rangements, or that the current was from the lead to the iron
through the liquid. But when the lead was tarnished before
it was put into the water, or when, being put into acids or
saline solutions, it was suffered to remain immersed a short
time, the deflection of the needle rapidly diminished, and
after a time took place in the opposite direction.

In the Bakerian Lecture for 1826, Sir H.Davy has given an
example, and pointed out the general cause, of such reversals
in the relations of metals ; but the particular case of lead is not
there noticed, and it occupies the same relative place in an
amended table of the order of metals given in that memoir
which it originally held in the series published by the same
philosopher in the Journal of the Royal Institution published
in 1802.

41. The power of deflecting the needle as measured by the
torsion of glass threads given by plates of lead and iron, com-
pared with that given by similar combinations of zinc and
copper with the same liquids, is shown approximately in the

* This is given in a memoir by Volta, Ann. de Chimic, torn. xl. p. 243,
1802, but he speaks of it as having been previously published.

94? Capt. P. Yorke on the Action of Water and Air on Lead.

following results, which probably also show the relative quan-
tities of electricity evolved.

1. Liquid distilled water: lead and iron gave -^th of the
force of similar plates of zinc and copper.

2. Liquid spring water used (4. and 5.) TVth. The lead as
zinc in both these experiments.

3. Sulphuric acid ^ a drachm, spring water 4 ounces,
^Vth; the lead being as zinc. In a few minutes the
order was reversed ; in one instance it was reversed in
one minute : the lead became as copper, and the force
TVth that given by copper and zinc.

In this state lead was found to be negative even to copper.

With a solution of potash, the lead as zinc, the force was
double that given by copper and zinc ; and though it di-
minished rapidly, no reversal took place.

With a solution of carbonic acid in distilled water, no di-
vergence of the needle took place on immersion of the plates
of iron and lead.

Conclusion,

The following seem to be the principal conclusions that
may be derived from the preceding experiments, and from
some facts mentioned by other inquirers.

When lead is immersed in distilled water containing air,
the lead combining with oxygen as derived from the air gives
rise to the formation of a hyd rated oxide, a portion of which,
equal to about , t\ 00th of the weight of the water, or a little
more, is dissolved (8.), (22.), (25.), (28.); — that besides the lead
dissolved, there are formed by the same agency two solid
products ; the first, in order of time, a very light crystalline
substance, which is either a mixture of (18.), or perhaps a
compound of (19.), equal proportionals of hydrate and carbo-
nate of lead ; the second an anhydrous oxide in grey la-
mellar crystals, and small white dodecahedrons (8.) That this
second substance has crystallized from its aqueous solution
is shown by its deposition on the iron (12.).

When small but variable proportions of saline substances
are dissolved in the water in which the lead is immersed, the
action just mentioned is prevented (Christison) ; the affinity of
water for the oxide of lead appears to be so weakened that
no hydrate is formed, and no solution takes place, but the
lead is slowly invested by oxide.

But it appears that when exposed to a confined atmosphere
loaded with aqueous vapour, and especially if in contact with
organic hygrometric substances, it becomes encrusted by car-
bonate, as in the case of bullets from cartridges, mentioned

Prof. Moseley on the Principle of Least Pressure, 95

by Mr. Faraday*, and the exterior of a water reservoir by
Becquerelf.

Most saline solutions, and the sulphuric and carbonic acids,
precipitate more or less of the lead from its solution in distilled
water, the neutral salts probably in the state of hydrate and
the acid salts and free acids in combination (22.).

That carbonic acid dissolved in pure water does not act on
lead, or dissolve any measurable portion of its oxide, if at
least there be an excess of oxide present, but that it is capable
of dissolving a minute portion of the carbonate, though pro-
bably such a quantity as is equivalent to less than £th the
oxide which distilled water is capable of taking up (28 — 36.),

The only spring water I examined which dissolved any
oxide of lead was free from carbonic acid (32.).

That with reference to ceconomical purposes, it will proba-
bly be found that such spring waters as act most on lead, act
least on iron, and vice versa.

That in the simple voltaic circle of lead and iron, when
both metals are bright, the lead is positive to iron, as Volta
originally placed it ; but that when the surface of the lead is
oxidized, it becomes negative to iron and copper.
12 Duke-street, Grosvenor-square, Philip YoRKE.

May 2, 1834.

XIV. On the Application of the Principle of Least Pressure to
the Theory of Resistances. By the Rev. H. Moseley, B.A.9
Professor of Natural Philosophy and Astronomy in Ki?ig's
College, London.^

ET Pt P2 P3, &c, represent the different resistances of the
-*-' system ; ux px yv a2 pa y2, us /33 y3, &c, their inclinations to
the axes ofxyz; xlylzv x2y2zq9 x3y3z3, &c, the coordinates
of the points of resistance; ul = 0, u2 = 0, u3 = 0,&c, the re-
lations existing between the coordinates of the several points
of resistance, by reason of the connexion of the parts of the
"System ; Mx M2 M3, the sums of the resolved parts of the given
forces of the system (z. e. those which are not resistances) in
the directions of three rectangular axes; Nx N2 N3 their mo-
ments about those axes.

.*. .2P = minimum.
ZP cos a + Mx = 0 ")

ZPcos/3+M2 = 0 V (1.)

Z*P cos y + Mo = 0. J

Journal of Science, vol.xvi. p. 163. f Ann. de Chimie, torn. liv. p. 146.
Communicated by the Author.

96

Prof. Moseley on the Application of the Principle

XP (y cos a — x cos /3) -f N, = 0 "|

2P \x cosy — z cos a) -f- N2 = 0 V

£P (z cos fa — y cos y) + N3 = 0. J

7/, = 0
2*2 = 0
"3= 0

&c. = 0.

(2.)
(3.)

(4.)

Cos9 at -f cos2 /3, + cos2 yx — 1

Cos9 a2 + cos9 /3, + cos2 y2 = 1

Cos9 a3 + cos2 /33 -f cos9 y3 = 1
&c. = 1.

Differentiating with respect to xxyx zv x2y2z2, &c,> tne resist~
ances of the system being considered functions of these quan-
tities both in respect to their magnitude and direction, we
obtain

fdP . dP dP k D . t 1 >

< -j- cosa§tr+— cos a 83/ + -7- cosaSs — P sin a8a V = 0

rf^cbis|8ti+j? cos/38j/ + ^cos/382--Psin/38/3 j = o|(l'.)

{^cosr^ + ^ cosy8j/ + ^ cos y8z-Psiny8yj = o)

"I j— ( j/ cos a— tr cos /3) 8 ,r + -7— (y cos a— .r cos (S) 83/

JP
4- 7— {y cos a— .r cos /3) 8z + P cos a 8^

— P cos/3 8#-Pj/sina$a-f P.r sin/3 8/3 j = 0

E J r- (.rcosy — * cos a) 8.r+ v (#cosy — z cos a) 83/

<ZP
-j-j- (.rcosy — 2 cos a) 8 z -f P cos y8.r S(2'.)

— P cos a 8 z— Pa: sin y8y+Pz sin«8a V =0

x\ die (z co*P-y cos y^Zx+(dy (* cos $~y cos i) s^

+ ^- (« cos/3— 3/ cosy)8y + P cos/38z
-Pcos y8#— Pzsin /38/3-f P,*y siny8y| = 0

of Least Pressure to the Theory of Resistances. 97

lil'tsi4vlttdyl+u1mtxl = 0'

u2' 8 x2 + u2" 8 y2 + u2"! 8 z2 = 0

&c. = 0J

Cos otj sin at, 8 a, + cos ft sin ft 8/3, + cos y! sin y1$yl= 0 '
Cos a2 sin a2 8 a2 -f cos ft sin /3 8 ft + cos y2 sin y2 8 y2 = 0
Cos a3 sin a3 8 «3 + cos /33 sin /33 8 ft + cos y3 sin y3 8 y3= 0
&c. = 0J

Hence, adding the above equations, having first multiplied
equations (1'.) by the indeterminate quantities A! A2 A3 re-
spectively; equations (2'.) byB1B2B3; equations (3'.) by
Aj A^ A3 A4, &c. &c. ; equations (4/.) by fx{ \l2 jx3 ft,4, &c. &c.

(3'.)

(4'.

!

rfP

^P=^

-r~{] + (A1 + B]y— B2z)cosa + (A2— B1(r+B3z
a> x

cos /3 + (A3+B2o:-B33/) cosy}

+ P(-B! cos/3 + B2cosy)+Aw' |.8r.

+ {g{l+(A1 + Bli/-Bl2)cos« + (A2-B1^
+ B3z) cos /3+ (A1 + B2j;-B3?/) cos y}
+ P(B1 cosa-BaCOsyHAi/'I.Sj/.

1 az l

-f B3z) cos/3 + (A3+B2^-B3j/) cos y}

+ P(-B2cos« + B3cosft + Aa'''}.8z

-p{(A1 + B1j/-B2s + j^cos«)sin«8a + (A2-B1^
+ B3z + |*cos/3)sin/38|3+(A3 + B2.r-Bg>y
-f p cos y) siny 8y I.

Now, let the indeterminate quantities At A2AS, Bl B2 B3,
X Xo Xo ... f^! ft2 p3 ... be taken so as to satisfy the equations of
condition (1.) (2.) (3.) (4.); *, yx z19 x2 t/2 z2 , x3y3z3 ... a, ft y,,
a2 £2 72» a3 ^3 73 •*• may tnen ^e considered independent vari-
ables-, and by the condition

3"P = a minimum,

Third Series. Vol. 5. No. 26. ^. 1834. O

98 Prof. Moseley on the Application of the Principle

we have

S2P «P «P S2P

So.'! dj^ c?zt &.r2

82P . 82P n Q .

-=— = 0, -7— = 0, &c. ; also

ssp : m> . s^P . s^p n « -

= 0, 1 a = 0, 1 = 0, -5 — = 0, &c. &c.

§«! OPj 87l 8«2

Let l + (Ai + B1^-B2») cosa + (A2-B^ + B3z) cos 0
+ (A3+B2x — B3y) cosy = L.

.\ L^? + P(-B1cos/3fB2cosy) + Xw' = 0
L j? +P ( Bx cos a-B3 cos y) + X «" = 0
L 5? + P(-B2 cos a + B2 cos/3) + x«?" = 0

tt z

Sin a-s Aj + Bjj/— B2^ + /x cos a > = 0 ~)
Sin/3«fA2--B1,r + B32: + |«, cos j8\ = 0 >. (6.)

Sin J A3+B2^— B3j/ + /x cosy J> = OJ

Multiplying the first of equations (6.) by cos a, the second
by cos /3, the third by cos y, and adding, observing that

cos2 a 4- cos2 /3 + cos2 y = 0,
we obtain

(Ai + Bjj/— B2z) cos a + (A2— B^ + Bg*) cos /3 + (A3 + B2#

— B3y) cosy 4-^ = 0;

.-. L+ju,— 1 =5 0.

Let A^Bjy-Bg* = K'

Aa-B^+Bg* = K"
A3+B2*-B3i, = K'"
.'.by equations (6.)

I*2 = K'2+K"2+K'"2.
Let jw. . L = K, .'.by equations (6.)
cos* K' cos/3 K" cosy K^

L " X' Tr""""!^ "TT " K*
.*. by equations (5.)

(70

of Least Pressure to the Theory of Resistances, 99

^ + PB'K"-B*KI" + *£ = 0
ax ft. JL

« + pB£-aK- + i<»*.

Eliminating A between these equations

„» *F __?/ dP , p S B,(M''K''+«'Ky.K'»(B9tt"+Bs»') ? (jl
dx dy \ K ^ j

»,^Z_^^P pt-Bg(a"K"'4VK'0+K"(BX"+B3M'? _^
* dx dz £ K )

Now 45- - — 4? = —

dP_ rfPrftf dP rf|/

dz " </# c?z d^ * dz

cTP w^ rfP _ 2^ rfP

*/ z " %i " dx u" ' dy'
Whence, substituting in the second of the above equations (7.)i
dividing by — Tn and adding to the first equation, we obtain an
equation of the form

1 ^P XT ~

where V is a known function of xy z. Eliminating z from
this equation by means of the known relation

u = 0
and integrating, we obtain

logg P + S = Y

Where S represents the integraiyVd<r taken with respect to
the variable x, and Y is an arbitrary function of y.
To determine the form of this function, we have

P dx + V - °' P dy + V - dy'
representing the value of -=— by V.

Also eliminating ^ equations (7.) assume the form

02

100 Prof. Moseley on the Principle of Least Pressure.

dx dy

1u"^ +u'^- + P.R" = 0
dx dy

.% eliminating^ and -^ - from these equations

_M'/V + tt'V'-?/^ + R'= 0
dy

_2«"V-w'V'h-z/^ + R" = 0

Between which equations if x be eliminated we shall obtain a
differential equation of the form

d-y t F* = °

where Fy is a known function of y.

.'. Y = C — fY y dy = v[/j/ is known
.-. loge P + S = $y

.-. P = £(^"s)

The values of P, cos a, cos /3, cos y, being thus found in
terms of x y z, and Pj P2, &c, cos «n cos a2, cos /315 cos /32 ...
cos y1} cos y2, being all supposed to be similar functions of
their corresponding coordinates, by substitution in equations
(1.) and (2.), we shall obtain six equations determining the
values of the six constants Ax A2 A3, JSX B2 B3, and thus the
solution will be complete.

The coefficients of 8 a, S /3, S y may be written thus :

{a . T> -o 1 d COS OL

Ai + B^-B^-f^cosaj^ . -j—

{a r> ™ „1 d cos B

Aa-B! x+B3z+ p. cos/3 J--^-

-|a3 + B3 x- B3y + p. cosy X . -^~

The equations (6.) will therefore be satisfied by any values
ofa/3y which are independent of xyz. That is, they will
be satisfied, provided the inclinations of the resistances to the
axes of xy z be the same for all the points of resistance ; that
is, provided the resistances be parallel to one another, and
therefore to the resultant of the other forces impressed upon
the system.

G. Rose on QsmuiiWumfrom the Ural. 101

It is otherwise manifest, that provided the fixed points on
which the system rests be capable of supplying resistance in
every possible direction, this parallelism is necessary to the
condition of a minimum amount of resistance.

When, however, the resistances of the system are supplied
by the contact of surfaces capable of motion upon one another,
this condition of resistance in every possible direction is not
satisfied ; the possible directions of resistance at each point
lying within the surface of a right cone having that point for
its vertex, the normal to it for its axis, and a certain angle
dependent upon the friction of the surfaces in contact for its
vertical angle.

In this general case, then, a parallelism of the resistances is
impossible, and we must determine the direction of each ac-
cording to the principles laid down in the preceding pages,
subject to such modifications as may be imposed by the na-
ture of the resisting surfaces and the other conditions of the
equilibrium of the system. The discussion of these is re-
served for a future Number of this Journal.

XV. On the crystallized Compounds of Osmium a?id Iridium,
found in the Ural. By G. Rose.*

Osmiridiumfrom r|^HE inclination of r and c, measured
Newransk. ■*• with the reflective goniometer, is 118°

nearly. The faces r, c and g possess but little lustre. Cleav-
age parallel to c9 but obtained with
difficulty. Colour tin white, rather
darker than native antimony. Lus-
tre metallic. Hardness equal to
that of quartz. Specific gravity
19*385, obtained by weighing 2*084
grammes of the mineral, selected with great care, in water, at
the temperature of 12°*3 Reaumur : a second experiment gave
19-471, the temperature of the water being 9° Reaumur.
Heated before the blowpipe on charcoal, it undergoes no
change, and does not give the slightest smell of osmium. It
smells slightly of osmium when melted with nitre in a matrass,
and forms a green mass after cooling. It is found in the
gold-sand of Newransk, 95 wersts north of Catharinenburg.
Platina occurs with it, but in much smaller quantities. It is
also found at Bilimbajewsk, Ryschtim, and many other places
in the Ural.

Osmiridiumfrom NischneTagil. — The crystals of this variety

* From Poggendorff's Annalcn, vol. xxix. Part III.

102 Mr. J. Hogg and Sig.Tenore on the comparative Influence

of osm indium have the same form, angles and cleavage as the
preceding. Colour lead-grey, like antimony glance. Hard-
ness that of the preceding variety. Specific gravity of several
crystals, which together weighed 1*5205 grammes, 21*118,
the temperature of the water being 13° Reaumur. Heated
before the blowpipe on charcoal, it does not melt, but the sur-
face becomes dull, and turns black, giving out at the same
time a penetrating smell of osmium.

XVI. On Phenakite, a new Mineral from the Ural. By
Nils Nordenskiold.#

'"PHIS mineral is found in Perm, 85 wersts from Cathari-
* nenburg. Its form is rhombohedral PP ae 115*25, &P
= 147*42^, wP= ! 22*1 7 J nearly. Cleavage parallel to??.
Hardness greater than that of
(juartz. Specific gravity 2*969.
Lustre vitreous. When pure it
is transparent and colourless.
Sometimes its colour is a bright
wine yellow inclining to red : it
is also found white and opake.
According to Hart wall, it is
composed of silica 55*14, glu-
cine 44*47, and traces of alumina and magnesia, amounting,
together with the loss, to 0*39. The composition of this mi-
neral is expressed by the formula Be + 2 S.

XVII. On the Influence of the Climate of Naples upon the
Periods of Vegetation as compared with that of some other
Places in Europe. By John Hogg, Esq., M.A., F.L.S.
F.C.P.S., $c.

[Continued from page 50 : and concluded.]

III. Efflorescence.

J^LOWERING (Efflorescentia), or the time in which plants
unfold their first flowers, is itself also subject to variations
no less remarkable than those mentioned in the other periods
of vegetation already described.

By comparing the observations reported by Linnaeus in his
Philosophia Botanica upon the flowering of many plants in
the neighbourhood of Upsal, and those by M. Chavassieux
d'Audibert in the environs of Paris, with my own researches

* From Poggcndorff's Annalen, vol. xxxiii.

of the Climate of Naples upon the Periods of Vegetation. 103

on the same species in the vicinity of Naples, between the
periods of efflorescence of these three places in Europe, there
result differences so well worth the careful attention of botanists
that I have considered it proper to collect them in the fol-
lowing comparative order.

Linnaeus in 1748 observed in Upsal the following times
of blossoming.

April.— 17. Anemone hepatica. 18. Fumaria bulbosa.
22. Tussilago Farfara. 23. Daphne Laureola. 24. Pulmo-
naria officinalis. 25. Draba verna. 26. Ornithogalum lu-
teum. 27. Viola canina.

May. — 1. Ranunculus ficaria. 2. Tussilago Petasites.
3. Lathraea Anblatum. 5. Viola hirta. 6. Primula veris.
7. Glechoma hederacea. 10. Oxalis Acetosella. 15. Draba
incana. 16. Leontodon Taraxacum. 17. Saxifraga granulata;
Orobus vernus. 18. Adoxa Moschatellina; Alchemilla vul-
garis. 19. Chelidonium majus. 24. Pyrus communis.
25. Ranunculus bulbosus. 26. Syringa vulgaris. 28. Ane-
mone Pulsatilla. 29. Empetrum nigrum. 30. Anemone ne-
morosa.

June. — 1. Geum urbanum; Thymus Serpyllum ; Bryonia,
alba ; Anchusa officinalis.

From Tenore's Journal of Botanical Observations, the fol-
lowing notices are extracted, relative to the efflorescence of
plants near Naples in the year 1800.

Dec. — Leontodon Taraxacum ; Narcissus unicolor [Ten.);
Senecio vulgaris ; Bellis perennis.

Jan. — 1 to 15. Cardamine hirsuta ; Daphne Laureola;
Galan thus nivalis; Mercurial is annua ; ThlaspiBursa-pastoris.
— 16 to 31. Ranunculus ficaria; Fumaria officinalis; F. ca-
preolata; Calendula officinalis; Vinca minor; Anchusa hy-
brida, (T.) ; Lycopsis bullata; Lamium purpureum; Ero-
dium cicutarium; Alsine media; Veronica Buxbaumii; Eu-
phorbia Peplus ; E. helioscopia; Tussilago Farfara; Bellis
annua; Ixia minima; Allium Chamae-moly; Narcissus prae-
cox ; Veronica hederaefolia.

Feb. — 1 to 15. Vicia Faba; Viola odorata; Synapis nigra ;
Cynoglossum pictum; Tussilago Petasites; Pulmonaria offi-
cinalis; Draba verna; Rosmarinus officinalis; Laurus nobilis ;
AmygdalusPersica; A. communis; Primus Cerasus ; P. Arme-
niaca. — 16 to 28. Crocus pusillus; Primula acaulis; Nar-
cissus Tazetta; Anemone apennina; Muscari botryoides;
Fragaria vesca; Ranunculus Philonotis ; R. bulbosus; R.
lanuginosus.

101 Mr. J. Hogg and Sig. Tenore on the comparative Influence

March, — 1 to 15. Alnus cordifolia; Pyrus Malus ; P. com-
munis ; Lamium flexuosum (T.) ; Scrophularia peregrina ;
Linaria officinalis : Glechoma hederacea ; Chelidonium majus;
Symphytum tuberosum ; Borago officinalis; Valantia cruciata.
— 16 to 31. Cyclamen hederaefolium; Euphorbia sylvatica ;
Veronica montana ; Silene lusitanica; Cerinthe aspera ; Co-
ronilla Emerus; Viola canina; Arum italicum; Vicia sativa;
Sambucus nigra.

April. — Iris germanica; Allium neapolitanum ; Staphy-
lea pinnata; Acer Negundo; Ornithopus compressus; Re-
seda undata; Ranunculus muricatus; Papaver Rhaeas; Li-
thospermum purpureo-cceruleum; Sanicula europa?a; Ber-
beris vulgaris; Robinia Pseudo-acacia; Erysimum officinale;
Valeriana rubra; Crataegus monogyna; Lychnis Flos-cuculi;
Thymus vulgaris; Euonymus europaeus.

May. — Castanea vesca ; Vitis vinifera ; Plantae cereales ;
Rubia tinctorum ; Valeriana officinalis ; Lavandula Spica ;
Delphinium peregrinum.

M. Chavassieux d'Audibert noticed the following periods
of flowering in the vicinity of Paris.

Jan. — Helleborus niger.

Feb. — Daphne Laureola; Galanthus nivalis; Anemone he-
patica ; Corylus Avellana.

March. — Viola odorata; Crocus vermis; Primula veris ;
Tussilago Petasites ; Narcissus Tazetta ; Prunus Cerasus ;
Amygdalus communis ; A. persica.

April. — Vinca minor ; Fragaria vesca ; Muscari botryoides;
Pyrus Malus ; P. communis; P. Cydonia; Syringa persica ;
Sambucus nigra.

May. — Cytisus Laburnum; Iris germanica; Anchusa offi-
cinalis; Symphytum officinale; Borago officinalis; Robinia
Pseudo-acacia ; Staphylaea pinnata ; Berberis vulgaris.

June. — Castanea vesca; Delphinium peregrinum; Papaver
album; Vitis vinifera; Lavandula Spica; Thymus vulgaris;
Plantae cereales.

[For the sake of continuing this inquiry in relation to the
efflorescence of some of the same plants in England, I will
here add the annexed catalogue taken from the Naturalist's
Calendar. The plants are arranged alphabetically ; and the
mean time is calculated between the earliest and latest dates
there given, as accurately as may be consistent, without divi-
ding the fraction of a day into hours and minutes.

of the Climate of Naples upon the Periods of Vegetation,

105

Flowering.

White at Selborne.

Markwick at Catsfield.

Earliest. Latest.

Mean.

Earliest.

Latest.

Mean.

Adoxa Moschatellina

March 18. April 13.

March 31

Feb. 23.

April 28.

March 1 1

Amygdalus persica . ..

March 2. April 17-

March 25

March 4.

April 29.

April 1

Anemone hepatica ...

Jan. 4. Feb. 18.

Jan.

26

Jan. 17.

April 9.

Feb. 26

Anemone nemorosa...

Mar. 17. April 22.

April

4

Feb. 27.

April 10.

March 20

Bellis perennis

Dec. 15.

...

Dec. 26.

Dec. 31.

Dec. 29

Berberis vulgaris

May 17. May 26.

May

21

April 28.

June 4.

May 16

Borago officinalis

June 20.

...

April 22.

July 26.

June 8

Bryonia alba

June 9.
July 6. July 9.

May 13.
April 20.

Aug. 17.
July 16.

June 30

Calendula officinalis..

July"

8

June 2

Corylus Avellana ...

Jan. 3. Feb. 28.

Jan.

31

Jan. 21.

Mar. 11.

Feb. 14

Crocus vernus

Jan. 13. Mar. 18.

Feb.

14

Jan. 20.

Mar. 19.

Feb. 18

Cytisus Laburnum...

May 18. June 5.

May

27

May 1.

June 23.

May 27

Daphne Laureola ..

March 25. April 1.

March 28

April 12.

April 22.

April 17

Draba verna

April 14.
June 20.

Jan. 15.

Mar. 24.

Feb. 18

Euonymus europaeus

May 11.

June 25.

June 2

Fragaria vesca. • >

April 23. April 29.
March 19-

April

26

April 8.

April 9.

April 9

Fumaria bulbosa

Galanthus nivalis

Jan. 10. Feb. 5-

Jan.

23

Jan. 18.

Mar. 1.

Feb. 8

Geum urbanum

May 28.

...

May 9.

June 11.

May 25

Glechoma hederacea

April 3. April 15.

April

9

March 2.

April 16.

March 24

Helleborus niger

Jan. 10.

...

April 27.

Lamium purpureum

Jan. 3. Jan. 21.

Jan.

12

Jan. 1.

April 5-

Feb. 17

Leontodon Taraxacum

Jan. 16. Mar. 11.

Feb.

1'2

Feb. 1.

April 17.

March 10

Lychnis Flos-cuculi...

May 29. June I.

May

30

May 12.

June 8.

May 25

Oxalis Acetosella

March 30. April 22.

April

10

Feb. 26.

April 26.

March 27

Papaver rhoeas

June 24.

...

April 30.

July 15.

June 7

C{Plantee Cereales.)

< Secale cereale

June 2.

...

May 27.

C Triticum hybernum

June 13. July '22.

July

2

June 4.

June 30.

June 17

Primula veris

April 3. April 24.
Feb.

April

13

March 3-

May 17.

April 5.

April 9

Primus armeniaca...

Feb. 28.

March 18

Prunus Cerasus

April 18. May 11.

April

23

March 25.

May 6.

April 15

Pulmonaria officinalis

March 4. April 16.

March 25

March 2.

May 19.

April 10

Pyrus communis

April 3. May 21.

April

27

March 30.

April 30.

April 14

PyrusMalus

April 22. May 25.
Feb. 21. April 13.

May
Marcl

8

April 11.
Jan. 25.

May 26.
Mar. 26.

May 3
Feb. 24

Ranunculus Ficaria..

|18

Sambucus nigra

May 26. June 25.

June

10

May 6.

June 17.

May 27

Sanicula europaea....

May 27. June 13.

June

4

April 23.

June 4-

May 14

Senecio vulgaris

Jan. 3. Jan. 15-

Jan.

9

Jan. I.

April 9.

Feb. 19

Symphytum officinale

June 13.

...

May 4-

June 23.

May 29

Syringa vulgaris

May 21.

...

April 1 5.

May 30.

May 7

Tblaspi Bursa-pastoris

March 3.

...

Jan. 2.

April 16.

Feb. 23

Thymus Serpyllum...

June 28.

...

June 6.

July 19.

June 27

Tussilago Farfara

Feb. 15. Mar. 23.

Marcl

1 5

Feb. 18.

April 13.

March 17

Valantia cruciata

July 9.

...

April 10.

May 28.

May 4

Valeriana officinalis..

June 22. July 7-

June

29

May 22.

July 21.

June 21

Veronica hedera?iblia

March 1. April 2.

March 17

Feb. 16.

April 10.

March 14

Vinca minor

March 25.
March 6. April 18.
Feb. 26. Mar. 31.

Feb. 6.

May 7.
April 22.
April 5.
July 29

March 23
March 26

Viola canina

March 27
March • *

Feb. 28.

Viola odorata

Feb. 7.

March 7
July 8

Vitis vinifera

June 7. July 30.

July

3

June 18.

But I have also given in one view the times of blossoming of
the same plants at Upsal, Naples, and Paris, according to
Linnaeus, Tenore, and d'Audibert, and the mean dates, as in-
Tfiird Series. Vol. 5. No. 26. Aw. 1 834. P

1 06 Mr. J. Hogg and Sig. Tenore on the comparative Influence

eluded in the preceding catalogue, of the same occurrence at
Selborne and Catsfield. I have thus arranged them in one

a, "

list.

Flowering.

Upsal.

Naples.

Paris.

Selborne.
(Mean.)

Catsfield.
(Mean.)

England.

Adoxa Moschatellina

May 18

...

March 31

March 1 1

March 21

Amygdalus persica ...

...

Feb. i— 15

March

March 25

April 1

March 28

Anemone hepatica ...

April 17

.,

February

Jan. 26

Feb. 26

Feb. 10

Anemone nemorosa..

May 30

...

April 4

March 20

March 27

Bellis perennis

...

December

...

Dec. 15

Dec. 29

Dec. 22

Berberis vulgaris

...

April

May

May 21

May 16

May 18

Borago officinalis

...

Mar. 1—15

May

June 20

June 8

June 14

Bryonia alba

June

June 5

June 30

June 1 9
June 20

Calendula officinalis

Jan. 16—31

...

July 8

June 2

Corylu3 Avellana ...

...

...

February

Jan. 31

Feb. 14

Feb. 7

Crocus vernus

...

March

Feb. 14

Feb. 18

Feb. 16

Cytisus Laburnum...

...

...

May

May 27

May 27

May 27

Daphne Laureola ...

April 23

Jan. 1 — 15

February

March 28

April 17

April 7

Draba verna

April 25

Feb. 1—15

April 14
June 2C

Feb. 18

March 17
June 1 1

Euonymus europaeus

April

...

June 2

Fracraria vesca.. .......

Feb. 16 28

April

April 26
March 19

April 9

April 17
March 19

Fumaria bulbosa

April 18

1

Galanthus nivalis

...

Jan. 1—15

February

Jan. 23

Feb." 8

Jan. 31

Geum urbanum

June ]

...

...

May 28

May 25

May 26

Glechoma hederacea

May 7

Mar. 1—15

April 9

March 24

April 1

Helleborus niger

...

...

January

Jan. 10

April 27

March 4

Lamium purpureum

...

Jan. 16—31

...

Jan. 12

Feb. 17

Jan. 30

Leontodon Taraxacum

May 16

December

...

Feb. 12

March 10

Feb. 25

Lychnis Flos-cuculi...

...

April

...

May 30

May 25

May 27

Oxalis Acetosella

May 10

...

...

April 10

March 27

April 3

Papaver r h ocas

...

April

...

June 24

June 7

June 15

C(Plant<z Cereales.)

...

May

June

< Secale cereale. .......

...

...

...

June 2

May 27

May 30

C Triticum hybernum

...

...

...

July 2

June 17

June 24

Primula veris

May 6

March

April 13

April 9
March 18

April 11

Prunus armeniaca ...

Feb. 1—15

February

Feb. 23

Prunus Cerasus

...

Feb. 1—15

March

April 29

April 15

April 22

Pulmonaria officinalis

April 24

Feb. 1—15

...

March 25

April 10

April 2

Pyrus communis

May 24 Mar. 1-

April

April 27

April 14

April 20

Pyrus Malus.....

Mar. 1 — 15

April

May 8
March 18

May 3
Feb. 24

May 5
March 7

Ranunculus Ficaria..

May' 1

Jan. 16— 31

Sambucus nigra

...

Mar. 16—31

April

June 10

May 27

June 3

Sanicula europaea ...

...

April

...

June 4

May 14

May 24

Senecio vulgaris

...

December

...

Jan. 9

Feb. 19

Jan. 29

Symphytum officinale

...

...

May

June 13

May 29

June 5

Syringa vulgaris

May 26

...

...

May 21

May 7

May 14

Thlaspi Bursa-pastoris

...

Jan. 1—15

...

March 3

Feb. 23

Feb. 27

Thymus Serpyllum...

June

...

...

June 28

June 27

June 28

Tussilago Farfara....

April 22 Jan. 16 — 31

...

March 5

March 17

March 1 1

Valantia cruciata

...

Mar. 1—15

...

July 9

May 4

June 6

Valeriana officinalis..

...

May

...

June 29

June 21

June 25

Veronica hederaefolia

...

Jan. 16—31

...

March 17

March 14

March 15

Vinca minor...

Jan. 16—31

April

March 25

March 23

March 24

Viola canina .<■...

April 27

Mar. 16 — 31

March 27
March 14
July 3

March 26

March 27

Viola odorata... .......

Feb. 1—15
May

March
June

March 7
July 8

March 10
July 5]

Vitis vinifera.. ........

From the comparison of these observations, every one will

of the Climate of Naples upon the Periods of Vegetation. 107

be able to reckon that the same plants flower in Naples two
months and a half (or ten weeks) earlier than at Upsal, and
a month (or four weeks) earlier than at Paris.

The considerations before explained respecting the in-
fluence of the difference of the seasons in accelerating or in
retarding the periods of vegetation, ought in every way to be
applied to the time of flowering. In like manner, as in the
period of leafing, we may, however, observe that the efflo-
rescence of plants varies from 1 5 to 20 days, according to the
changes in the temperature of the different years.

[Now, before we estimate the times of blowing at Naples
with those of the same plants in England, it will be necessary
first to reduce each of the dates before given to a more cer-
tain medium day between an early and a late year, by taking
18 days as the mean varying time, which, for the purpose of
showing the variations in the different Neapolitan seasons, and
of being compared with those in the English seasons given in
the catalogue at page 105, I have computed in the following
manner :

Flowering.

Amygdalus persica . .
Borago officinalis . . .
Calendula officinalis
Daphne Laureola . .

Draba verna

Fragaria vesca

Galanthus nivalis . . .
Glechoma hederacea
Lamium purpureum
Prunus armeniaca.. .

Prunus Cerasus

Puhnonaria officinalis
Pyrus communis ....

Pyrus Malus

Ranunculus Ficaria

Sambucus nigra

Thlaspi B ursa-pastoris
Tussilago Farfara . .
Valantia cruciata . . .
Veronica
Vinca minor . .

Viola canina

Viola odorata

Feb.
Mar.
Jan.
Jan.
Feb.
Feb.
Jan.
Mar.
Jan.
Feb.
Feb.
Feb.
Mar.
Mar.
Jan.
Mar.
Jan.
Jan.
Mar.
hederaefolia Jan.
Jan*
Mar.
Feb.

As before
at Naples.

1—15

, 1—15

16-31

1—15

1—15

16-28

1—15

1—15

16—31

1—15

1—15

1—15

1—15

1—15

16—31

16—31

1-15

16-31

1—15

16-31

16—31

16—31

1—15

18 days earlier.

Jan. 14—28

Feb. 11— 25

Dec. 29— Jan. 13

Dec 14—28

Jan- 14—28

Jan. 30— Feb. 11

Dec. 14—28

Feb. 11—25

Dec.29— Jan. 13

Jan. 14—28

Jan. 14—28

Jan. 14—28

Feb. 11—25

Feb. 11—25

Dec 29— Jan. 1 3

Feb.26— Mar. 13

Dec. 14—28
Dec.29— Jan. 13

Feb. 11—25

Dec.29— Jan. 13

Dec. 29— Jan.13

Feb.26— Mar.13

Jan. 14-28

B.

18 days latter.

Feb. 19— Mar. 5
Mar. 1 9— April2

Feb. 3—18
Jan. 19— Feb. 2
Feb. 19— Mar. 5

March 6—18
Jan. 19_Feb. 2
Mar. 19— April 2

Feb. 3—18
Feb.l9_Mar. „
Feb.l9_Mar. 5
Feb. 19— Mar. 5
Mar. 19_ April 2
Mar. 19_ April 2
Feb. 3—18
April 3—18
Jan. 19— Feb. 2

Feb. 3—18
Mar. 19— April 2
Feb. 3—18
Feb. 3—I8
April 3—I8
Feb. 19— Mar. 5

Jan. 21— Feb.26
Feb. 18— Mar.26
Jan. 5— Feb. 10

Mean of
A and B.

Dec. 21 — Jan. 2 6 Jan.

5 J

Jan. 21— Feb.26
Feb. 5— Mar. 12
Dec.21— Jan.26
Feb. 18— Mar.26
Jan. 5— Feb. 10
an. 21— Feb.26
Jan. 21— Feb.26
Jan. 21— Feb.26
Feb. 18— Mar.26
Feb. 18— Mar.26
Jan. 5 — Feb. 10 Jan.
Mar. 5— Apr. 10 Mar
Dec. 21— Jan. 26 Jan.
Jan. 5 — Feb. 10 Jan

True
Mean.

Feb.
Mar
Jan.

Feb.
Feb.
Jan.
Mar,
Jan.
Feb.
Feb.
Feb.
Mar
Mar

Feb. 18— Mar.26
Jan. 5— Feb. 10

Mar.
Jan.

Jan. 5 —Feb. 10 Jan,

Mar. 5 — Apr. 10
Jan.21— Feb.26

Mar.
Feb

En-
gland.

Mar. 28
Junel4
June20
Apr. 7
Mar. 17
Apr. 1/
Jan. 31
Apr. 1
Jan. 30
Feb. 23
Apr. 22
Apr. 2
Apr. 20
May 5
Mar. 7
June 3
Feb. 27
Mar. 11
June 6
Mar. 15
Mar.24
Mar.27
Mar. 10

Therefore, from a calculation of the mean dates given in
the last two comparative Tables, there results this general
difference in the times of flowering in those countries, that is
to say, the efflorescence of the same species of plants occurs

P 2

108 Mr. J. Hogg and Sig. Tenore on the comparative Influence

sooner at Naples by above seven weeks, at Paris from two to
three weeks earlier, and at Upsal by about Jive weeks later %
than it is wont to do in England.

But in computing more exactly the times of this cycle of
vegetation, little reliance only can be placed on the notices
with regard to Upsal and Paris, for Linnaeus seems to have
made his observations in one single year, and d'Audibert has
fixed no precise days of the given months ; and moreover they
have both neglected to state the number of days which vary
in the blossoming of these plants, according to the tempera-
ture of the weather in early or late years. On the contrary,
the dates given by White and Markwick are the earliest and
latest times of flowering for a great many years ; and the mean
of these having been calculated, will establish as accurately as
possible the true date for the return of this period of vegeta-
tion in England in every ordinary season.]

IV. Friictescence.

At the time in which the fruits spontaneously fall, or are
easily plucked, off the mother plant, begins that period of ve-
getation which we distinguish by the name of fructescence
(fructescentia) ; to this we may apply the same observations
that have been made in the preceding articles upon the varia-
tions which the influence of the climates, of the seasons, and
of the atmosphere exerts upon the different periods of vege-
tation. Therefore with us (at Naples) the ripeness of fruits
is about 20 days earlier or later, according as the spring and
summer have been hotter and more rainv, or drier and more
temperate.

Linnaeus has observed that barley and wheat ripen on the
4th of August at Upsal. Near Naples these sorts of corn are
reaped in June in Terra di Lavoro and in Puglia ; and in
July in Abruzzo.

[Owing to the proportionably greater heat that is prevalent
in the summer in Sweden, and to the more speedy vegetation
than in England, the wheat harvest will be found from the
annexed view not to be any earlier with us than at Upsal,
but to begin at the same time ; and barley to ripen ten days
later with us than in Sweden.

Harvest

begins.

Upsal.

Wheat .
Barley .
Oats....

Aug. 4
Aug. 4

Naples.

June
June

White at Selborne.

Earliest. Latest. Mean

July 21
Aug. I.
Aug. 1.

Aug. 23
Aug. 26
Aug. 16

Markwick at Catsfield.

Earliest. Latest. Mean

En-
gland.

Aug. 6July II. Aug.26Aug. 3 Aug. 4
Aug. 13| July 27. Sept. 4 Aug.15 Aug.14
Aug. 8'July 26, Aug. 19 Aug. 7 Aug. 8]

of the Climate of Naples upon the Periods of Vegetation. 109

Cherries* do not ripen at Paris before the latter part of
June, whilst at Naples they are eaten from the first week in
May.

These facts always confirm the difference of the relations
between the periods of vegetation in those parts of the world.

V. Defoliation,

When the trees begin to be stripped of their leaves, vege-
tation finds itself arrived at that its last and mournful period,
which botanists call defoliation {defoliatio) .

This phenomenon, in trees which annually lose the whole
of their leaves, takes place in the beginning of the autumn. In
evergreen trees the leaves prolong their vegetation beyond the
first year, and die after the new ones have already expanded
themselves. Although botanists have not paid great attention
to the fall of the leaf in evergreen trees, this phenomenon,
however, it may be shown, does not happen in periods less
constant than those which are observed in trees with annual
leaves, concerning which 1 will limit myself to relate some
few comparative notices.

The fall of the deciduous leaves being produced by the tor-
pidness which acts on the motion of the vegetable juices, in
consequence of the diminution in the temperature that is
felt in the autumnal months, must necessarily be early in cold
countries and late in warm climates ; and, indeed, similar va-
riations in the years and weather exercise upon defoliation a
similar influence to that which we have seen to prevail in the
other times of vegetation.

Hence it is that at Upsal, the Hazel, the Ash, the Lime,
the Maple, and the Poplar cast their leaves at the first sign
of autumn ; at Paris these same trees lose them in October,
whilst at Naples they keep in full leaf through the whole
month of November. The Apple, the Fig, the Elm, the
Birch, and the different kinds of Oaks, which at Paris are
deprived of their leaves in the beginning of November, near
Naples often retain them throughout December. Since, how-
ever, the coldness of autumn sometimes takes place very early,
as it did in the years 1807 and 1812, the fall of the leaf itself
is likewise premature.

[Whitef observes, on the order in which trees lose their
leaves in England, — "One of the first trees that becomes naked
is the Walnut: the Mulberry, the Ash, especially if it bears
many keys, and the Horse Chestnut come next. All lopped
trees, while their heads are young, carry their leaves a long

* According to White, near Sclbornc Wild Cherries are ripe July 22.
f Works in Natural History, vol. ii. p. 245.

1 10 W. West on a remarkable Analogy between

while. Apple trees and Peaches remain green very late, often
till the end of November. Young Beeches never cast their
leaves till spring, — till the new leaves sprout and push them
off': in the autumn the beechen leaves turn of a deep chest-
nut colour. Tall Beeches cast their leaves about the end of
October."]

But it is worth while to state that there grows with us (at
Naples) an exotic tree which preserves its deciduous leaves
almost to the end of the appearance of the new ones, and
consequently seems to confound itself with evergreen trees.
This species is the Salix babylonica, commonly called Salcio
piangente, or Weeping Willow.

[I will now conclude this memoir in again endeavouring to
impress strongly upon the minds of my readers the great be-
nefits that may ultimately be bestowed on science by institut-
ing careful inquiries into the changes and periods of vegeta-
tion in different situations both at home and abroad, and by
comparing the results of their labours in various parts of the
globe ; and finally, in recalling their attention to the following
memorable words of the illustrious Swede :

" Calendaria Florae quotannis conficienda sunt in quavis
provincial, secundum [Germinationem^Frondescentiam, [Efflo-
rescentiam,~] Fructescentiam, Defoliationem, observato simul
Climate, ut inde constet diversitas regionum inter se."]

XVIII. On a remarkable Analogy between 'ponderable Bodies,

and Caloric and Electricity. By William West.*
COME years have elapsed since the attention of chemists
*? was called, by Dulong and Petit, to the relation between
the specific heats and the atomic weights of simple bodies.
Their experiments and conclusions, though at first called in
question, have since been confirmed and extended by others.
The relation which they discovered has been variously ex-
pressed ; it was thus announced by themselves : " The specific
caloric of simple bodies is inversely as their atomic weights."
It has since been thus stated : " A given quantity of heat will
elevate the same number of degrees a portion of every simple
substance represented by its atomic weight." A third mode
is: " The specific heats multiplied by the atomic weights give
a constant quantity." This variety of expression deserves
notice, because it may have tended to obscure, if not to con-
ceal, the analogy between caloric and ponderable bodies, which
it is my purpose to point out. The analogy in question is
this : The quantity of caloric separable from, or combining

* Communicated by the Author.

ponderable Bodies, and Caloric and Electricity. 1 1 L

with, bodies, as measured by their power of imparting or abs-
tracting heat, is exactly proportional to the quantity of any
ponderable (simple) substance separable from, or combining
with, the same bodies, as ascertained by weighing. Thus it
requires, according to the law of Dulong and Petit, twice as
much caloric to elevate the temperature of a pound of sulphur
10 degrees, as it does to raise that of a pound of zinc to
the same extent^ and a pound of heated sulphur will warm
twice as much water, or any third substance, as a pound of
equally hot zinc. Now this is exactly what takes place among
ponderable substances. A certain weight of sulphur combines
with twice as much oxygen, or chlorine, as the same weight
of zinc does, in forming the correspondent compound and
gives up twice as much on entering into a fresh combination.
If we were to adapt to the ponderable body oxygen, the
phraseology which we are accustomed to use in regard to ca-
loric, we might say then, and the fact would be correct, how-
ever unusual the expression, that the " capacity " of sulphur
for oxygen is twice as great as that of zinc. Again, " the
quantities of oxygen combined with by sulphur and zinc are
in inverse ratio to the weights of the atoms of those bodies."

Again, a given quantity of oxygen will raise, in the scale of
oxides, portions of zinc and of sulphur represented by their
atomic weights. Once more, " the weights of oxygen in the
corresponding oxides, multiplied by the atomic weights, give
a constant quantity." For 16 parts of sulphur combine with
8 oxygen, 16 zinc with 4 oxygen, but 8x16 = 4 x 32. This
ground of analogy between caloric and ponderable bodies is
so obvious, that it would seem as if it must have occurred to
many, yet I have never seen it adverted to. If it has really
escaped some who might have been expected to notice it, the
difference in our modes of expressing facts thus closely corre-
sponding, when the subject is caloric and when it is a ponder-
able body, furnishes one reason for the oversight. Another
is found in the circumstance that in our experiments and re-
ports of experiments on the relation of bodies to heat7 we ac-
custom ourselves to equal quantities of the bodies compared,
and variable quantities of caloric.

We are accustomed, on the other hand, to take a fixed
quantity of any ponderable substance, and a variable quantity
of those whose combinations with it we compare together.
But how this analogy has remained without mention is of
minor consequence. 1 wish to draw attention to its existence,
and to a fact, exactly corresponding to it in the history of elec-
tricity. Mr. Faraday, in his 7th series of researches in that
science, says that the quantity of electricity set free during

1 1 2 The Rev. P. Keith on the Internal Structure of Plants.

galvanic action by certain weights of particular bodies, is pre-
cisely the same with that which is required to separate them
from their combination with other particles when subject to
electrolytic action. He describes one experiment in parti-
cular, in which " the chemical action of about 32 parts of
zinc, arranged as a voltaic battery, was able to evolve a cur-
rent of electricity capable of decomposing and transferring
the elements of 9 grains of water*." Here we may remark the
difference in expression, while the fact stated is the same. If
for electricity we say iodine, the quantity " set free," or
" called into action," during the decomposition of an atom of
iodide of zinc, is precisely the same which is required " for
forming a new compound on the decomposition of an atom of
water." I am aware that the once prevalent doctrine of the
materiality of caloric and electricity has given way before the
conclusions deduced from certain optical phacnomena; but if
the being subject to similar laws of combination with material
bodies has no weight in restoring them to a place among
forms of matter, it may still assist us in investigating others of
their relations.

XIX. On the Internal Structure of Plants. By the liev.

Patrick Keith, F.L.S.f
"PROM the previous survey of the vegetable structure J, it
-■- appears that the organs into which the plant is externally
distinguishable are the root, trunk, branches, buds, leaves,
flower, and fruit, or seed. These we may call decomposite
organs. But the organs which are thus discoverable by ex-
ternal inspection are each and all of them reducible to com-
ponent parts, which we will call composite organs, and which
are again resolvable into constituent parts also, that is, into
primary or elementary organs, the detection and exhibition
of which are the ultimate object of the researches of the vege-
table anatomist.

Decomposite Organs.
The Seed.— In the dissection and anatomy of the seed, no
botanist has been so successful as Gaertner. His work De
Seminibus et Fructibus Plantarum, a work meritorious beyond
all praise, is the best guide to the knowledge of carpology,
and is to be studied in conjunction with the actual inspection
and analysis of seeds. Seeds are divisible into two parts, di-
stinguishable without much difficulty, namely, the integuments

* See Lond. and Edinb. Phil. Mag., vol. iv. p. 294, 295.— Edit.

+ Communicated by the Author.

j See Lond. and Edinb. Phil. Mag., vol.iii. p. 78, and 1 20 etscq.— Edit.

The Rev. P. Keith on the Internal Structure of Plants. 113

and nucleus, or the embryo and its envelopes. The integu-
ments of seeds are generally two, but sometimes three or four,
distinguished in the nomenclature of the present day by the
terms, primine, secundine, tercine, quartine. The exterior
integument, or primine, the * testa* of former anatomists, is the
original cuticle of the nucleus, not detachable in the early
stages of the seed's growth, but detachable at the period of
the maturity of the fruit. The integument next in order is
the secundine. It originates in the umbilical cord, which,
after perforating the testa, or primine, expands either imme-
diately, as if from the hilum, or mediately, and from a distinct
chalaza, into a multiplicity of ramifications, connected by a fine
and delicate membrane that lines the exterior integument, and
immediately envelopes the nucleus, unless it should happen to
be furnished with a tercine.

The nucleus, or kernel, is that part of the seed which is
contained within the proper integuments, consisting of the al-
bumen, with the vitellus, when present, and embryo.

The albumen is an organ resembling in its unripe state the
white of an egg when raw, and in its ripened state the white
of an egg when boiled, and forming for the most part the ex-
terior portion of the nucleus, but always separable from the
interior or remaining portion. In the grasses it forms the
principal mass of the nucleus and constitutes the farina of
the seed; but in leguminous plants and in the Composite it
is not at all to be found, at least as a distinct organ.

The vitellus, or yelk, where it exists, is an organ of a fleshy
but firm contexture interposed between the albumen and
embryo, to the former of which it is attached only by adhe-
sion, but to the latter by incorporation of substance. There
are many tribes of plants in which its presence cannot be de-
tected, but it pervades the whole of the extensive family of
the grasses, where it assumes the form of a scale on which the
embryo rests.

The embryo, which is 'the last and most essential part of the
seed and the final object of the fructification, as being the germ
or primordial rudiment of the future plant, is a small, pulpy,
and very often minute organ, inclosed, for the most part,
within the albumen, and occupying very generally the centre
of the seed. It is divisible into two distinct and conspicuous
parts, namely, the cotyledon and the plantlet.

The cotyledon is that portion of the embryo which incloses
and protects the plantlet, and springs up during the process
of germination into what is usually denominated the seminal
leaf, if the lobe is solitary, or seminal leaves if there are more
lobes than one. In the former case the seed is said to be

Third Series. Vol. 5. No. 26. Aug. 1834. Q

114? The Rev. P. Keith on the Internal Structure of Plants,

monocotyledonous, in the latter case it is said to be dicoty-
ledonous, and in the case of its having no cotyledon at all it
is said to be acotyledonous. Of plants now known to bo-
tanists 6000 species are found to be acotyledonous, 6000
monocotyledonous ; and 32,000 dicotyledonous, making a
total of 44,000 species* described and arranged according to
the prevailing systems; an ample and magnificent Flora of the
globe that we inhabit, but not yet complete, for still there
are regions of the earth's surface unexplored, and flowers
without a name :

et sunt sine nomine floresf.

The plantlet is the interior and most essential portion of
the embryo, the seat of vegetable life, and the germ that
expands into a perfect plant ; in short, it is the future plant
in miniature. In some seeds it is so minute as to be scarcely
perceptible, while in others it is so large as to be divisible
into distinct parts. Take and dissect a garden bean, and you
will have no difficulty in detecting it. It is situated near the
external scar, and is partly lodged within the lobes, and
partly in a small and conical process projecting beyond the
general line of their circumference and uniting them together.
The portion that is lodged within the lobes corresponds to the
caudex ascendens of Linnaeus, being the rudiment of the fu-
ture leaf and stem, and generally denominated the plumelet ;
and the portion that is lodged within the conical process cor-
responds to the caudex descendens of Linnaeus, being the rudi-
ment of the future root, and generally denominated the ra-
dicle.

The Bulb. — If the solid bulb, or what has been called the
solid bulb, is taken and divided into halves by a vertical or
longitudinal section, it will be found to consist externally of
a sort of fibrous or membranaceous envelope, separable into
two or more layers; and internally of a fine epidermis, in-
closing a firm but succulent pulp, in the centre of which are
lodged the rudiments of the future plant. The bulb of Gla-
diolus communis or of Colchicum autumnale affords a good ex-
ample, in which the several parts of the flower may be di-
stinctly perceived long before the period of their natural evo-
lution ; yet modern botanists do not admit the existence of a
solid bulb; it is now a coronus, or souche souterraine\.

If the coated and scaly bulbs are taken and dissected, they
will be found to exhibit similar appearances. Particularly if

* Cows de Vhyt. par M. Du Petit Thouars.

t Ovid, Fast., lib. iv. p. 441.

X Lindle)'s Introduction to Botany, p. 52.

The Rev. P. Keith on the Internal Structure of Plants. 1 15

the bulb of the Tulip is taken up in the beginning of the
month of January, and carefully bisected in a line passing
through its longitudinal axis, the petals, the stamens, the
pistil, and the incipient stem may be already all distinctly per-
ceived, small and delicate in their appearance, but complete
in all their parts.

The Bud. — If the scales of a bud are stripped off, and dis-
sected under the microscope, they will be found to consist of a
thin epidermis, inclosing a pulp interspersed with a network
of fibres. But buds produce either leaves, or flowers, or both,
and it was to be presumed that leaves and flowers must exist,
in an incipient state, in the bud, long before the period of
their natural evolution; which presumption the dissection of
buds has shown to be the fact, as the following example will
demonstrate. In the month of March 1810, I opened up a
bud of the Horse Chestnut that had not yet burst its scales.
The scales, which were about fifteen or sixteen in number, be-
ing removed, were found to contain one pair of opposite leaves,
now laid bare, the divisions of which were closely matted to-
gether with a fine down. The leaves upon being opened were
found to inclose a flower-spike, consisting of not less than
a hundred florets compactly crowded together, and each en-
veloped by its own downy calyx, which when opened disco-
vered the corolla, stamens and pistil distinct, the rudiments
of the future fruit being also discernible in the ovary.

The Flower. — If the calyx or corolla is carefully dissected
with the assistance of a good glass, it will be found to consist
of the following several and distinct parts: an epidermis, or
external envelope ; a parenchyma, or soft and pulpy mass ; and
bundles of longitudinal threads or fibres originating at the
base, and subdividing and ramifying throughout the expan-
sion, so as to form a thin and flat network. The stamens and
pistils seem to consist merely of a fine epidermis, inclosing a
soft and pulpy parenchyma, without exhibiting any traces of
longitudinal threads or fibres, or but very rarely so. The
filaments of the Tulip are tubular, which is, as I believe, a
very rare occurrence.

The Leaf.— -The leaf, like the calyx and corolla, is found
upon dissection to consist of an epidermis, a parenchyma,
and multitudes of interspersed fibres. Take a leaf of com-
mon sorrel, and tear it asunder, either in a transverse or
longitudinal direction, and fragments of a fine and transpa-
rent pellicle will be seen projecting beyond the edge of the
torn part. This is the epidermis. When the epidermis is
stripped off, the parenchyma appears, — a green and pulpy
mass interspersed with the prolongations of the fibres of the

Q2

116 The Rev. P. Keith on the Internal Structure of Plants.

petioles, which are divided into a prodigious number of rami-
fications mutually embracing and intersecting one another,
and forming a fabric similar to a piece of fine network. The
principal fibre, extending from the base to the apex of the leaf,
forms what is called the midrib; the lateral ramifications form
what are called the nerves or veins; terms borrowed from the
animal kingdom, but calculated to mislead as having no func-
tions in common with the nerves or veins of animals. Yet
many leaves have no transverse fibres. In monocotyledonous
plants the fibres are parallel to the midrib. But the most
singular circumstance in the structure of the leaf is, not
that the fibres are subdivided into a variety of ramifications
forming a fine network, but that the network thus formed is
double, being actually composed of two distinct layers, the
one corresponding to the upper, and the other to the un-
der surface of the leaf. In the leaf of the Orange-tree the
network consists of even three layers, as the dissection, or
rather the maceration, of that leaf will show, and no lan-
guage is able to convey an adequate idea of the delicacy and
intricacy of the web.

The Caudex, or Mass of the Trunk and Root. — In opening
up the caudex, whether ascending or descending, the dissector
will soon discover that its internal structure, like its external
aspect, or habit, is materially different in different tribes of
plants. This was long ago pointed out by Grew in his Ana-
tomy of Trunks, and w?ell illustrated by plates. It was further
illustrated by Plumier in his Treatise on the Ferns of Ame-
rica, as also by Linnaeus; and still more recently by Messrs.
Daubenton and Desfontaines*, who have investigated the sub-
ject with great ability, as we cannot but admit, but who by
generalizing their notions, perhaps somewhat too hastily,
have applied and restricted the modes of organization which
they illustrate rather incorrectly to certain tribes of plants.
Thus, the two modes of internal structure which they demon-
strate and describe are presumed to correspond respectively
to monocotyledonous plants on the one hand, and to dicoty-
ledonous plants on the other, the caudex of the latter be-
ing represented as composed of distinct concentric and diver-
gent layers, and the caudex of the former as exhibiting merely
bundles or assemblages of large, longitudinal, and woody
fibres interspersed throughout a pith,— but the fact is, that the
two modes of internal structure here specified do not uni-
formly and respectively pervade the two grand divisions of
plants now in question. If all monocotyledonous plants are

* Mem. dc /' Instil. Nat., torn. i.

The Rev. P. Keith on the Internal Structure of Plants. 117

destitute of the aforesaid layers, all dicotyledonous plants are
not furnished with them. The caudex of Water-Hemlock
(Cicnta virosa) exhibits no traces of layers, whether concen-
tric or divergent, though belonging to the dicotyledonous
class; and the bulb of the common Onion (Allium Cepa) is
furnished with concentric layers, at least, though belonging to
the monocotyledonous class. In short, there are great diffi-
culties resulting from the adoption of this principle. Where
are we to place the Filices; where the Orchidece'i And from
what are we to take our distinctions? From the seed, or from
the plant? To these questions no satisfactory answer can be
given ; and hence it is evident, that if any general division
arising from internal structure is to be adopted, it must not be
instituted upon the ground of the number of the cotyledons.

As all our classifications of the works of nature are but
arbitrary groupings, and are but seldom commensurate with
the arrangements of the Divine mind, we can scarcely expect
to find a classification that shall be unexceptionable. The fol-
lowing divisions are advanced, not with any pretension to
peculiar accuracy or excellence, but merely as exhibiting a
general view of that scale of vegetable organization by which
plants are found to ascend from the lowest and least perfect,
to the highest and most perfect forms*.

I. The caudex a homogeneous and cellular mass, pulpy,
powdery, crustaceous, or leather-like, not distinctly divisible
into trunk and root, not generally furnished with the several
appendages of branch, leaf, and conspicuous flower or fruit;
but resolvable merely into an epidermis and an inclosed
pulp, or parenchyma.

II. The caudex a symmetrical .assemblage of heterogeneous
organs, vascular as well as cellular, divisible into trunk and
root, furnished for the most part with the several appendages
of branch, leaf, and conspicuous flower, or fruit; and re-
solvable into rind, pulp, and interspersed longitudinal fibre ;
the cellular structure predominating.

III. The caudex a symmetrical assemblage of heteroge-
neous organs, vascular as well as cellular, divisible into trunk
and root; furnished for the most part with the several ap-
pendages of branch, leaf, and conspicuous flower and fruit ;
and resolvable into bark, wood, and pith ; the vascular struc-
ture predominating.

The first division comprehends the lowest orders of vege-
tables, that is, orders exhibiting the fewest traces of organiza-
tion, the caudex being merely a mass of pulp enveloped in a

* Keith's Phys. Bot., vol. i. p. 286.

118 The Rev. P. Keith on the Internal Structure of Plants,

fine epidermis. This is the simplest mode of vegetable struc-
ture, as has been observed by M. Mirbel in his Anatomy of
Plants. It may be exemplified in a variety of species belong-
ing to the class Cryptogamia, particularly in the orders Algcc
and Fungi. In the Alga you have a good example of it in
Tremella arborea, which presents, upon external inspection,
the appearance of a sort of irregular mass of wrinkled pulp
or jelly, of a brown or reddish colour, adhering to the surface
of rotten timber or trunks of decayed trees, without any visible
root, and without the appendage of either branch, or leaf, or
of conspicuous flower or fruit. If you cut it open it still pre-
sents to you merely the appearance of a mass of pulp, or of
parenchyma covered with a fine epidermis, that is, of a struc-
ture wholly cellular. It is well known to many people who
are not botanists by the name of Witches' Butter. In Tre-
mella Nostoc you have an equally good example, as also in
the several species of Clavaria, Sph&ria, Peziza, and many
other Fungi. But the subjects of examination should be taken
when young, for when they are old they are no longer pulpy.

The second division comprehends the middle orders of
vegetables, that is, orders exhibiting more manifest traces of
organization than the foregoing, the caudex being now partly
vascular, as consisting of an epidermis that incloses a volu-
minous pulp, interspersed with bundles of longitudinal threads
or fibres. This mode of structure prevails chiefly in herba-
ceous and annual, or biennial plants, and necessarily involves
some considerable variety, the pulp being sometimes solid and
sometimes tubular, and the fibres being in both cases some-
times scattered and sometimes contiguous, sometimes arranged
irregularly and sometimes in a determinate order.

The Pulp solid. — If the stipe of Aspidium Filix-mas is di-
vided by a transverse section towards the base, it will be
found to consist of an epidermis inclosing a firm and con-
sistent pulp, and to exhibit upon the surface of the section
five circular spots, of a darker colour than the rest, arranged
in a line forming about three fourths of the circumference of
a circle, and concentric to the circumference of the stipe.
The spots are the divided extremities of five bundles of lon-
gitudinal nerves, as may be rendered evident by opening up
the stem longitudinally, when the several bundles will appear
in the form of strong threads, each surrounded with a proper
rind or covering, of a brown colour and membranaceous tex-
ture, and extending through the whole length both of the
stipe and rachis.

The Pidp tubular. — If the stem of the Garden Parsnep,
Pastinaca sativa, which constitutes externally a fluted column,

The Rev. P. Keith on the Internal Structure of Plants. 119

is divided by a transverse section, it will be found to consist
of an epidermis, containing a hollow cylinder of pulp, thickly
set with bundles of longitudinal fibres disposed in a circu-
lar row, and lined with a soft and spongy pith, which is it-
self tubular, and lined with a fine and transparent mem-
brane, consisting of a most intricate plexus of soft and de-
licate fibres, forming an ultimate cavity, which is sometimes
partly filled up with a fine and cottony down, or with fine
and transverse diaphragms resembling cobwebs.

It should be added that the tubular stem does not neces-
sarily form one single and continued cylinder, except in the
Agarics, but rather a succession of individual cylinders united
to one another by joints, or knots, that form transverse dia-
phragms interrupting the continuity of the tube, even though
it is furnished with no pith, as in the grasses. But though
the trunk of this order of plants is often tubular, yet the root
is not often tubular, — though the root of Water-Hemlock fur-
nishes an exception, — but is wholly filled up with pulp and
interspersed fibre, or with layers similar to those of the orders
that follow.

The third division comprehends the highest orders of ve-
getables, that is, orders exhibiting the highest degree of vege-
table organization, the caudex being now more decidedly
vascular in its structure, as well as more perplexingly intri-
cate in its analysis, as consisting of an outer, an intermediate,
and a central part, or, in other words, of a bark, wood, and
pith, each having an aspect and texture peculiar to itself.

It has been observed that the progressions of nature are
not made per saltum, and doubtless there is truth in the re-
mark. The various tribes of plants graduate imperceptibly
into one another ; and if the arrangements of nature inter-
mingle, so must ours also. Thus, between the first and second
of the foregoing divisions there are plants to be found par-
taking of the character of both, as the dissection of the lobes
and peduncle of Marchantia polymorpha will evidently show.
The lobes are cellular, the peduncle is vascular*. The same
thing may be said of the second division, and the division
now under our consideration (as coming in sequence). The
structure of this last is best exemplified in shrubs and trees.
Yet nature does not pass per saltum from plants that are purely
herbaceous on the one hand, to plants that are purely woody
on the other. There is an intermediate order, partaking of
the character of either class, that forms the connecting link.
In the latter case the wood is perfect, in the former case it is
imperfect.

* Keith's Phys. Bot., vol. i. p. 228-344.

120 The Rev. P. Keith on the Internal Structure of Plants.

TheWood impel feet. — If the root of the Beet {Beta vulgaris)
is taken, and cut open by a transverse section, it will be found
to exhibit a most beautiful example of the union of the con-
centric and divergent la}'ers as inclosed within a bark and
inclosing a pith, and remaining at the same time wholly her-
baceous. But the mature stem of the full-grown plant ap-
proaches in part to the consistence of wood, and points out its
affinity to shrubs and trees.

If the stem of the common Cabbage (Brassica oleracea) is
divided transversely, it will exhibit, first, a bark ; then an
inclosed cylinder of a firm and compact texture, interspers-
ed with a multiplicity of divergent rays, and approaching to
the consistence of wood ; and then a large and firm pulp or
pith. The same structure pervades the root also, which is
furnished with but little pith. In some stages of the plant's
growth the concentric layers are not discernible on the trans-
verse section; but in its stage of decay the divergent layers
disappear, and the woody cylinder separates spontaneously
into a number of fine and concentric layers resembling
lace.

The Wood perfect. — If the trunk of a tree or shrub, such as
that of the Oak or Elder, is divided by means of a trans-
verse section, the parts that are peculiarly characteristic of
this division will be rendered visible. The outer portion is
the bark. In young subjects it is of a flexible and leathery
texture, consisting, first, of an epidermis or external pellicle ;
secondly, of a layer of cellular tissue, called the cellular in-
tegument ; and thirdly, of a number of thin and concentric
layers, designated by the name of the cortical layers, and tra-
versed, at least in aged subjects, by a multiplicity of divergent
rays. The intermediate portion of the trunk is the wood,
constituting the main body of the full-grown plant, and exhi-
biting on its horizontal section an indefinite number of con-
centric layers, intersected by an indefinite number of diver-
gent layers issuing from the centre like the rays of a circle,
but often alternating with incomplete rays that do not issue
from the centre. The interior portion of the trunk is the pith,
a soft and ^spongy substance, of a whitish colour, lodged in
the centre of the wood as in a tube. It is always most abund-
ant in the young shoot, of which it constitutes the principal
mass. But as the wood increases, the pith diminishes, and in
old and full-grown trunks it totally disappears.

The structure of the branches is similar to that of the trunk,
as is also the structure of the root with its divisions, at least
till you reach the extreme radicles, which present the appear-
ence of a cylindrical mass of pulp inclosed in a fine epidermis,

Mr. Hopkins on the Stratification of Derbyshire, 121

and inclosing a firm and longitudinal fibre, or rather a bun-
dle of longitudinal fibres united into one cord, like the fila-
ments that compose the nerves of animals, and which termi-
nate ultimately in soft, bibulous, and club-shaped appendages
designated by the appellation of spongiolce.

Thus we trace in plants the foundation of three grand orders,
depending upon the relative simplicity or complexity of the
structure of the caudex, and presumed to exhaust the subject.
They agree in point of number, but not in point of specific
extent, with the arrangements of modern botanists, by which
plants are reduced to three grand orders depending upon the
structure of their seeds — the acotyledonous, the monocoty-
ledonous, and the dicotyledonous. Whether or not these
groupings of threes give any support to Professor Burnett's
system of triads, I am not able to say ; but what we learn,
unequivocally, from the foregoing investigation is, that the
decomposite organs of all plants, to whatever division be-
longing, are reducible to one or other of the following con-
stituent parts — epidermis, pulp, pith, cortical layers, ligneous
layers, fibre— to the analysis of which we now proceed.
[To be continued.]

XX. Bemarks on Farey's Account of the Stratification of the
Limestone District of Derbyshire. By W. Hopkins, Esq.,
M.A.,Mathematical Lecturer of St.Peter' sCoUegc,Cambridge,
and Fellow of the Geological and Cambridge Philosophical
Societies.

To the Editors of the Philosophical Magazine and Journal.
Gentlemen,
AM R. CONYBEARE, in the latter part of his " Inquiry how
■*-*•*- far De Beaumont's theory is applicable to the mountain
chains of this country," which appeared in the Number of the
Philosophical Magazine for June, in speaking of the elevated
chain of hills which ranges N. and S. through our northern
counties, has expressed considerable doubts as to the accuracy
of Farey's account of the geology of the limestone district of
Derbyshire, which forms the southern extremity of the chain ;
and this I observe has led you to refer, in a note, to an abs-
tract, published in the Phil. Mag. for January, of an account
which I laid before the Cambridge Philosophical Society of
an investigation I had recently made of one or two important
points in the stratification* of that county. During the spring
of the present year I have had an opportunity of extending
my investigation over the greater part of the district; and as

Third Series. Vol. 5. No. 26. Aug. 1834. R

122 Mr. Hopkins's Remarks on Farey's Account of the

I have now so fully satisfied myself of the entire erroneousness
of Farey's views of its stratification, I will, with your permis-
sion, enter with some detail into a refutation of them.

Before I notice those points on which Farey and myself
differ so widely, I will mention one in which we are entirely
agreed, viz. the regular interstratification of the toadstone
with the limestone. The direct evidence of this is afforded
by those cliffs in which the fact is matter of observation ; and
the indirect evidence of it must be sought in the circumstance
of our being able to found on this hypothesis a generalization
which shall clearly and distinctly embrace all the particular
phenomena which the stratification of the district presents to
us. The validity of this latter evidence must, of course, de-
pend on that which can be offered in proof of the generaliza-
tion contended for; but as the examination of this evidence
would necessarily involve the complete discussion of the sub-
ject, into which it is far from my intention to enter at present,
I must content myself with stating my conviction of the fact
of this interstratification of the toadstone. Any opinion of its
unconformability with the limestone beds, professing to rely
upon observation, can only, I think, be founded on a superficial
examination or on an imperfect conception of the subject. I
mention my conviction on this point more particularly in conse-
quence of Mr. Conybeare's having suggested, in the paper
above alluded to, the possible unconformability of the toad-
stone, from its having, perhaps, been thrust up among the
limestone beds at a period posterior to their formation. In
addition, however, to the reasons above mentioned, I conceive
that any such idea must be completely negatived by the total
absence of all indications of that mechanical violence which
must necessarily attend the forcible intrusion of a mass of ig-
neous rock among masses previously deposited.

1 will proceed, however, to the exposition of what I con-
ceive to be erroneous in Farey's account of the district.

He has asserted (and it should be recollected that on this
subject he has made many assertions, but has given no
proofs,) that there exist in the limestone district of Derbyshire
three distinct beds of toadstone. The limestone occupying the
surface, and lying above the first or highest toadstone — that
between the first and second toadstones — that between the
second and third — and that beneath the third — he has termed
respectively theirs/, second, third, and fourth limestones. He
states that these beds of toadstone have continuous bassets,
that of the third or lowest bed commencing on the north near
Castleton, and ranging by Wormhill, Chalmerton, Pike Hall,
and the Grange to Bonsai Dale ; and those of the two other

Stratification of the Limestone District of Derby shire. 123

beds ranging nearly parallel to the above basset at short di-
stances to the west of it.

Let us first consider the two latter bassets, i. e. those of his
first and second toadstones. He asserts that they commence
on the north at the great fault (which he assumes to run N.
and S. between Castleton and Litton,) not far from Wind-
mill Houses, the first passing near the village of Litton and
the second near Tideswell. Now of the existence of a toad-
stone basset anywhere to the north of Litton, where these
are said to commence, I have not been able to find the most
remote indication, either in my own examination of the spot,
or in the information 1 have derived from the most intelligent
miners in the neighbourhood ; and moreover I can myself
bear positive testimony to the fact that the toadstone near
Tideswell, which Farey asserts to belong to the second bed,
belongs to the same as that at Litton, which he has assigned
to the Jirst, for I have most distinctly traced the toadstone
without the smallest interruption from the one place to the
other. It is manifestly brought up by the E. and W. fault
which has elevated Litton Edge.

Again, (if I understand him rightly, which is sometimes no
easy matter, even with the aid of his able commentator*,)
Farey says, that the first basset passes nearly at the southern
extremity of Crossbrook Dale, and from thence to Fin Copt
Hill; and that the second passes from near Tideswell to the
southern extremity of Tideswell Dale next the Wye, ranging
thence easterly along the sides of Miller's Dale and Monsal
Dale till it descends to the level of the river Wye, at the
mouth of Crossbrook Dale, and that crossing the river at that
point, it returns westerly along the opposite side of the valley
to the top of Priestcliff Lowe.

Now, in the first place, I deny the possibility of tracing any
continuous basset from Litton to the south end of Crossbrook
Dale, or from the point where the toadstone appears north of
Tideswell to the southern extremity of Tideswell Dale; nor is
there the slightest indication in either case of any faults by
which the bassets between those places respectively might be
hidden. In the second place, the toadstone which appears in
the southern part of Crossbrook Dale is not the western ex-
tremity or basset of the bed to which it belongs, for nothing
can be more manifest than that the bed passes across the
dale, of which for some distance it occupies the whole of the
lower part, ascending in exactly a similar manner on both

* See "Geology of England and Wales," in which Mr. Conybeare has
given an exposition of Farey 's views far more intelligible than that which
Farey himself has given of them.

R2

124« Mr. Hopkins's Remarks on Farey's Account of the

sides of it to the height (where the upper surface of the bed is
most elevated,) of perhaps 200 feet. It has manifestly been
raised to this position by an E. and W. fault which ranges
nearly parallel to the valley of the Wye, and is here about
300 or 400 yards from it. The toadstone is here seen, from
the bottom of the dale to the height just mentioned, to abut
directly against the limestone, which forms, as it were, a
solid wall intervening between the toadstone and the valley of
the Wye, thus concealing the raised edge of the toadstone as
we proceed westerly along the latter valley till we come to
Litton Mill, where the intervening wall becomes too low for
that purpose, and accordingly the toadstone then reappears,
its upper surface being high in the side of the valley, at an
elevation exactly corresponding to its position in Crossbrook
Dale. From this place it is easily traced to the southern ex-
tremity of Tideswell Dale, the point at which Farey asserted
the toadstone to belong to his second bed ; whereas the facts
I have now stated establish the identity of the beds at Tides-
well Dale and Crossbrook Dale as clearly as I have esta-
blished a similar identity at Litton and Tideswell, as above
mentioned.

It must be carefully observed here, that the partial toad-
stone basset I have just described nowhere descends down
the side of Monsal Dale or Miller's Dale to the level of the
river, as it must necessarily have done had there been a con-
tinuous complete basset crossing the river at the mouth of
Crossbrook Dale, as Farey describes ; and in like manner on
the south of the river the toadstone ranges at a considerable
elevation along the side of the valley, as on the opposite side,
but nowhere, as far as I have been able to ascertain, does it
descend continuously to the margin of the river. I conceive
this toadstone to have been elevated by a fault exactly similar
to that on the N. side of the river, and exactly parallel to it.
According to this view of the subject the valley of the Wye,
from Chee Tor to the point near Longstone, must have been
originally formed by two parallel faults, 400 or 500 yards
as under, the strata being elevated on the N. side of the more
northern, and on the S. side of the more southern fault,
leaving the intermediate portion in nearly its original position.
In this intermediate portion the lower part of the present
valley has been formed, as I conceive, by erosion. The small
inclination of the lines of stratification, and their almost un-
broken continuity in the precipitous rocks which rise imme-
diately from the margin of the river between Crossbrook Dale
and the upper end of Miller's Dale, attest the slight disturb-
ance which the portion of the limestone beds between the

Stratification of the Limestone District of Derbyshire. 125

faults has suffered, while on either side of the valley, beyond
the faults, we find such undoubted indications of immense dis-
locations.

The formation of this curious and beautiful vale, cutting
completely through the elevated central ridge of the district,
perpendicularly to its direction, is thus simply accounted for.
I have entered with some detail into the explanation of it tor
the purpose of comparing it with the necessary deductions
from Farey's view of the subject. He asserts, as I have be-
fore mentioned, that the basset of the second toadstone crosses
the Wye at the mouth of Crossbrook Dale*, in which case
the limestone forming the N. side of Monsal Dale, imme-
diately E. of this point, must be the second, and as such
Farey has in fact described it. But this limestone is seen in
Crossbrook Dale, at the fault about 300 or 400 yards from
the Wye, to abut directly against his first toadstone, as above
described. Hence we must conclude that the limestone
on the south side of this fault (instead of that on the north
side, as I conceive,) has been elevated, and to an immense
height, since the first limestone and first toadstone are no
longer superincumbent upon it. And yet it is in this mass of
limestone thus elevated above the adjoining part, accord-
ing to Farey, that the present deep valley of the Wye has
been excavated. How the river first selected such a course
is most marvellous. The explanation I have myself given of
the formation of this valley will at least appear to have the
testimony of hydrostatical principles in its favour.

It is almost incredible that so industrious an observer as
Farey must have been, should have failed to note any one of
the longitudinal faults in the district bordering the Wye,
though they are so frequent and characteristic, following al-
most to mathematical accuracy the law of parallelism. We
might suppose from his account of this interesting tract that
the stratified masses which it comprises remain, relatively at
least to each other, in the regular and undisturbed order in
which they were first deposited, although in its external cha-
racters we cannot fail to mark the most obvious indications of
violent dislocation. This is not, however, the only instance

* A patch of toadstone which is seen at this point at the level of the
Wye has, no doubt, led to this erroneous notion. It must not be con-
founded with that before mentioned in the southern part of Crossbrook
Dale as belonging, according to Farey, to his first bed. According to my
own view of the subject it belongs to the undisturbed portion of limestone
and toadstone lying between the two parallel faults described above.
Other patches show themselves at several places along the valley, indi-
cating that this undisturbed portion of the toadstone lies just beneath the
bed of the river.

126 Mr. Hopkins's Remarks on Farey's Account of the

in which our geologist has shown such an aptitude to make
" the crooked straight, and the rough places plain."

But to proceed *with Farey's imaginary bassets. The first
basset passes, he says, from Crossbrook Dale to Fin Copt Hill.
I assert in answer, that there is no continuous basset between
those points, nor can I find the slightest evidence of any
N. and S. fault which might conceal it. From Fin Copt Hill
it is said to range south-westerly by Flagg and Moneyash to
Gratton Dale near Elton ; but on what authority the assertion
can possibly rest, I cannot form the most remote idea. I have
carefully examined several parts of this range, and have made
most diligent inquiry respecting the basset among the most
intelligent miners at Moneyash, and have never been able to
discover the slightest evidence of its existence between Fin
Copt Hill and Gratton Dale. In like manner the supposed
second basset is said to range from Priestcl iff Lowe west of
Moneyash, at a short distance from the first ; but where it was
conceived to pass over the E. and W. range of hill between
Taddington and the basin in which Moneyash is situated, I
could never understand either from Farey's work or from
Mr. Conybeare's interpretation of it. I have, however, most
positive evidence that such is not the line which the basset
from Priestcliff Lowe follows, having distinctly traced it from
the summit of the Lowe continuously to the E. and imme-
diately to the S. of Taddington to the basset by Chilmerton
(considered by Farey as the third basset,) on the one hand,
and by the W. of Taddington and Blackwell on the other,
to the foot of the Lowe, from the summit of which I had set
out; thus absolutely demonstrating that the toadstone found
at the foot of the Lowe as we descend to the Wye belongs to
the same bed as that at its summit, though Farey has asserted
the latter to belong to the second, and the former to the third
bed.

I can offer no explanation of these discrepancies on simple
matters of fact between Farey's statements and my own. I can
only hold myself responsible for the facts I have stated.

From Gratton Dale to Masson Lowe and Matlock High
Tor, the bassets I have traced agree more nearly, though still
imperfectly as regards the second of them ; but in his account
of Masson Lowe he has fallen into exactly the same error as
at Priestcliff Lowe, and the exposition of it is effected exactly
in the same manner. The constitution of this curious hill,
however, is too intricate for me now to enter into any descrip-
tion of it*.

* In my first examination of this intricate hill (which I was obliged to
make hastily) I conceived the toadstone at Bonsai to be the tirst. A more

Stratification of the Limestone District of Derbyshire. 127

It would be useless for me to dwell upon other points in
which Farey has fallen into errors exactly similar to those I
have already pointed out, and from the same cause — a total
neglect of the great distinction between a partial and a com-
plete basset. Those of which I have more particularly spoken
in the vicinity of the Wye are manifestly of the former, in-
stead of being, as he has represented them, of the latter class;
and hence we have the important conclusion that the basset
immediately to the west of them, from Copt Hill to Chilmerton,
must belong to the same and highest bed, instead of being the
third, as Farey has represented. I have no doubt too of this
basset being only a partial one, terminating shortly after
crossing the Ashborne and Buxton road, to the south of Chil-
merton. Hence, again, I conclude that the limestone west of
this line of basset is theirs* limestone, instead of being the
fourth, according to Farey's notions. The toadstone ranging
N. and S. between Dove Hole and the Wye, about two miles
E. of Buxton, must, again, be the highest, and the limestone on
the surface at this western boundary of the district must have
been of contemporaneous formation with that on the eastern
side, and passes (in this north-western portion of the boundary
which I have more particularly examined) under the shale and
grit hills with a gentle dip to the west.

Here, then, Farey and myself are completely at issue re-
specting that portion of what he calls the great limestone fault
which ranges, according to his account, along this western
boundary of the district, and which, on his supposition of the
fourth limestone occupying the surface, must necessarily be
estimated at nearly 2000 feet, not merely in particular places,
but along every part of its range. Now though I have not
yet examined the whole of this boundary with the attention
which I hope shortly to devote to it, I have examined a con-
siderable portion of it north of Buxton, and I can only observe
(as I have already observed respecting some other statements
of Farey's,) that I am totally at a loss to conceive on wThat
evidence his assertions respecting this fault can rest. That
partial faults exist along this boundary as in other parts of
the district, I doubt not ; but I will venture to assert that no
evidence can be found of any such continuous fault as that
contended for; and I confess that it appears to me most mar-
vellous that Farey should have persisted in a theory which
involved as a necessary consequence the existence of this enor-
mous fault, in opposition, as I believe, to all the direct evi-

detailed examination has convinced me that if there be two toadstones
here, it is the second.

128 Mr. Hopkins's Remarks on Farey's Account of the

dence and obvious appearances in that part of the boundary
to which I have more particularly referred.

That a great N. and S. fault, however, does exist, I have
no doubt, though inferior in importance and very different in
position to that which Farey imagined. It is this fault which
has brought to the surface the toadstone basset already men-
tioned as extending from Copt Hill to the south of Chilmer-
ton, and has produced that central elevated ridge which
forms the principal feature in the external character of the
district. Of this I believe that I shall be able on some future
occasion to offer the most indisputable evidence. Farey's ac-
count of the great E. and W. fault at the southern extremity
of the limestone agrees with my own observations as far as
they have yet extended, which is not far west of Hopton ; but
whether any N. and S. fault meets this further westward
I have not yet ascertained. At the northern extremity of the
district, instead of a fault ranging along the whole extreme
boundary, an E. and W. one ranges from the north side of Copt
Hill, where it meets the great N. and S. fault, to Castleton.
That described by Farey as extending from Castleton nearly
to Litton, is, I believe, totally unsupported by the slightest
evidence.

If we would allow to a geologist on the one hand unli-
mited power of introducing faults, and on the other an un-
controlled command of denuding agents, he must be greatly
wanting in ingenuity if he could not devise almost numberless
systems of stratification for a district like Derbyshire. These,
however, are not powers to be delegated to any geologist
merely for the purpose of supporting his own theory; but we
have seen, notwithstanding, how boldly Farey has asserted the
existence of faults without reference to the evidence of facts ;
and in his denuding hypotheses we find a character of still
greater hardihood. It is manifest that according to his
theory, his Jirst, second, and third limestones, together with his
Jirst, second, and third toadstones, must necessarily have been
swept away by some means from an extensive tract of coun-
try, and this too without leaving a trace of the mighty opera-
tion behind. Probably he considered also that the shale and
gritstone had shared the same fate ; but for all this, and for
much more that still continues to puzzle geologists, he con-
ceived he had found an adequate cause in the extraordinary
hypothesis of a large satellite revolving at so small a distance
from the earth as must have rendered him a most trouble-
some neighbour; for he accuses him of being, by his powerful
attraction, the source of all those disturbances of which such
manifest indications still exist on the face of the earth, and

Stratification of the Limestone District of Derbyshire. 129

among other things of having carried off the Derbyshire lime-
stones. He appears, according to the same philosopher, to
have terminated his existence by precipating himself to the
earth, thus, after having long disturbed the peace of his pri-
mary, violating in his last act the universal laws of motion*.

Now it is very true that theoretical absurdities are not ne-
cessarily associated with imperfect statements of facts, or in
all cases with incorrect generalizations of them ; and moreover
I do not think that geological blunders of five-and-twenty years
ago demand any great severity of criticism; but absurdities
such as those to which I have just alluded are quite intoler-
able, even though their date were very long prior to the com-
mencement of the present century, and assuredly inspire us
with little reverence for the philosophical opinions of the per-
son who fell into them, or for any particular views with which
he associated them.

From the representation I have given of Farey's opinions
of the stratification of this limestone part of Derbyshire, it
might almost appear that thiey are scarcely worth the trouble
I have taken to refute them. It must, however, be recollected
that such refutation can only rest on a much more detailed
examination of the district than geologists in general can have
an opportunity of giving it, and that, in fact, these opinions
have, to a certain degree, stood the test of such cursory in-
vestigations as some of our most eminent geologists have made
of it; that Farey has been frequently appealed toon this sub-
ject during the last twenty years; and moreover that Mr.
Conybeare, in the " Geology of England and Wales," (a work
distinguished for its general accuracy in the geological details
of this country,) whatever doubts he may have entertained as
to Farey's accuracy on particular points, has nevertheless con-
sidered him sufficient authority for a detailed account of the
district in question. For these reasons I shall not, perhaps,
appear to have given an undue importance to the refutation
of the opinions against which I have been contending.

I shall conclude with a short abstract of the views I have
myself formed on the stratification of this limestone district,
premising, however, that my examination of some of its details
is not yet complete.

1 . The toadstone is interstratified with the limestone. It
cannot, I conceive, have been forcibly protruded among the
limestone beds, but must have been diffused over the surface
of the country at the time of its emission (assuming it to be of
igneous origin).

* See Phil. Mag. for 1807, vol. xxviii.; and for 1808, vol. xxxi.
Third Series. Vol. 5. No. 26. Aug. 1834.. S

1 30 Mr. Hopkins's Remarks on Farey's Account of the

2. The period of the disturbance or disturbances which
produced the present dislocations of the superficial strata
must have been long posterior to that of the production of the
toadstone, since the beds of toadstone have suffered exactly
the same dislocation as the limestone.

3. One and the same bed of toadstone pervades the whole
district N. of Middleton Moor (by Youlgrave), the limestone
above it, occupying the surface, being of contemporaneous
formation in every part of it*. There is no valid evidence of
the existence of a second bed beneath.

4. In the portion of the district S. of Middleton Moor, I
have not yet obtained evidence perfectly conclusive as to there
being one or two beds of toadstone. If there be two, it would
seem almost necessary that the lower one should be contem-
poraneous with the one above described, the upper one being
probably of very limited extent.

5. The principal transverse or N. and S. fault is that al-
ready described as extending from Copt Hill to the S. of
Chelmerton, the strata on the E. of it being elevated. Many
other partial ones, however, exist along the eastern side of the
district from Bakewell to Cromford and Wirksworth, and
along the north western boundary. In the former, where the
dip is easterly, the E. side is almost without exception the
most elevated ; and in the latter, where the dip is westerly, the
W. side is the elevated one. Of the south-western side I
cannot yet speak in detail.

These faults are not distinguished, like the longitudinal E.
and W. faults, by strict rectilinearity and persistency in their
direction. They are rather formed of a number of partial
faults, the directions of which are nearly parallel, and of which
the extremities do not exactly meet.

6. The great E. and W. faults are numerous, and their
common direction coincides with the mean dip of the strata.
They are remarkable for their rectilinearity and parallelism
to each other.

7. Each of these longitudinal faults is accompanied by one
of those fissures which are become so well known to us as mi-
neral veins, this fissure being generally though not universally
on the elevated side of the faulty to which they are near and
parallel.

Conversely, each of the large rake veins, about fifteen or six-

* It was only on renewing my investigation in the spring that I came to
this conclusion. Before I had examined Farey's third basset, I took for
granted its continuity, and therefore regarded it as the complete basset of
the first toadstone, and consequently the limestone beyond it to the W.
as the second.

Stratification of the Limestone District of Derbyshire. 131

teen in number, which form together the great system of pa-
rallel veins characteristic of the district, is accompanied through
at least a considerable part of its course by a fault,

8. A small system of parallel veins is sometimes found
independent of the general system, but having this character
in common with it, — that the common direction of the system
coincides with the particular dip of the strata in which it is

formed.

9. Though fissures, I have no doubt, accompany the trans-
verse as well as the longitudinal faults, they much more rarely
become good mineral veins, and I know of none that are con-
tinuous as such for any considerable distance. Instances, how-
ever, are not wanting of productive veins of this class.

10. Many small veins exist in the direction of which I have
detected no general law. These cross veins, however, are for
the most part incomparably smaller as fissures than the great
E. and W. veins above mentioned.

11. All the great springs of this district are found in con-
junction with the great faults. I do not at this moment recol-
lect an exception to this rule ; for, I believe, in every instance
where I observed a powerful spring I had independent evidence
of the existence of a great fault. The water is also generally
observed to proceed from the upper surface of the toadstone,
as might be expected from the circumstance of its being unable
to penetrate it. The circumstances attending the positions of
these springs, when carefully examined, offer a curious corro-
boration of the fact of the regular interstratification of the
toadstone beds.

12. I have observed no indications of a central point from
which the toadstone might be conceived to have flowed as from
a crater; nor have I yet observed any very distinct appear-
ances of an altered state of the limestone at its junction with
the toadstone. My attention, however, has not yet been so par-
ticularly directed to this latter point. Should any of your
readers have detected instances of this kind, I should feel
obliged for any information respecting them.

We may remark that this view of the subject does not in-
volve, as an essential part of it, the supposition of any great
and extensive denudation, but merely that local and partial
operation of denuding causes which must be recognised in al-
most every district.

I remain, Gentlemen, yours, &c.

W. Hopkins.
St. Peter's College, Cambridge,
July 18, 1834.

S2

[ 132 ]

XXI. Dr. Prout's Reply to Dr. W. Charles Henry. *

To the Editors of the Philosophical Magazine and Journal,
Gentlemen,

T N reply to Dr. C. Henry, I take the opportunity of stating,
-*- once for all, that I have neither time nor inclination to en-
ter into a controversy on any opinions advanced in my Bridg-
water Treatise. That these opinions would provoke discussion
I expected, and, indeed, rather wished, as such discussion
would be likely to lead to the truth — my great and only ob-
ject. Hypotheses and theories I care nothing about, further
than they are true ; and whoever can convince me that any
hypothesis which I have published is not true, will be esteemed
a friend.

It is now nearly twenty years since a paper containing
views virtually founded on the hypothesis attacked by Dr.
Henry was published by me in your Journal f; and from
that time to the present I have seen no reason to doubt its
truth. With respect to the facts stated by Dr. Henry, most
of them (and, indeed, many more which he has not mentioned,)
are quite familar to me, as I presume they must be to every
one who has attended to the subject. Of his reasoning I shall
say nothing. Whether the point in question can, or cannot be
legitimately deduced from a comprehensive and correct view
of the principles, our mathematicians will soon decide. In
the mean time, however, I have no hesitation in stating, that
such a mass of evidence exists in favour of the hypothesis,
(which evidence, if no one else does, I may be induced at
some time to arrange and publish,) that nothing but a mathe-
matical demonstration that it cannot be true, will at pre-
sent convince me of its error.

It only remains to state, that I have always adopted the
fundamental principle of atomic weights, or definite propor-
tions, established by Dr.Dalton; and have always reflected with
pride that this most important doctrine was first taught by an
Englishman : but that I never did adopt, and I fear, never shall
be able to adopt, some of the details of his " atomic theory."
Indeed I have always considered the atomic theory, as ex-
plained by Dr. Dalton, far less satisfactory and complete, as a

* See our last Number, p. 33. — Edit.

f See Annals of Philosophy, Old Series, vol. vi. and vii. (1815 and 1816)
" On the relation of the specific gravities of gaseous bodies, and the
weights of their atoms." This relation, it need scarcely be stated, is
founded on the hypothesis in question, understood, but not expressed.

Prof. Forbes on the Pyro-electricity of Tourmaline. 133

whole, than his theory of gaseous bodies and of vapours ;
which, had he done nothing else, would have placed him at
the head of modern physical inquirers in this, and in every
other country. I remain, Gentlemen, yours, &c.

Sackville-Street, July 18, 1834. W. Prout.

XXII. An Account of some Experiments on the Electricity of
Tourmaline, and other Minerals, when exposed to Heat. By
James D. Forbes, Esq., F.R.SS. L. 8? Ed., Professor of
Natural Philosophy in the University of Edinburgh* .

\ LTHOUGH the phenomena of the pyro-electricity of
<*% minerals, as it has been termed, and those of the tourma-
line in particular, have, after a long period of neglect, been
recently studied by more than one philosopher of eminence,
there is a sufficient number of undetermined or debatable
points, even at the threshold of the inquiry, to yield facts of
novelty and interest to those who will take the trouble to look
for them.

Having during the past summer been much engaged in
studying the relations of bodies to heat and electricity, I was
induced, by having in my possession a considerable number
of long tourmalines, to repeat and endeavour to verify some
recently published experiments with this mineral. These in-
quiries brought out several new facts; and, with the hope
of adding something to our knowledge in this curious field,
I have taken this opportunity of communicating to the Society
the results of some very recent experiments.

My attention was principally directed to the verification
and extension of the views of M. Becquerel, whose ingenious
papers published in the Annates de Chimie for 1828, give us
almost the only information, with the exception of a short
paper by Dr. Brewster published in 1824, which we have
gained on this subject since the appearance of the works of
Haiiy. The undecided state in which several points of the
first importance were left by the philosophers of the last cen-
tury is not a little remarkable. In fact, the answer to the

* From the Transactions of the Royal Society of Edinburgh, vol. xiii.
This paper was read before that Society on the 3rd of January 1832: the
author explains as follows the delay in its publication :

U The publication of this paper was delayed partly under the idea of
prosecuting the experiments of which it contains an account j but the
author having engaged in some other researches, which appear to him of
more immediate importance, he merely prints this communication in its
original form. — April 1834."

1 34 Prof. Forbes's Experiments on the Electricity of

fundamental question of whether the tourmaline must be in
the act of changing its temperature, in order to the develop-
ment of electricity, may be considered to rest on the authority
of Becquerel (who answered it in the affirmative), former au-
thorities being divided upon it.

Dr. Thomson, in his work on Heat and Electricity, pub-
lished in 1830, observes, that " when the tourmaline is once
excited by heat, it retains its electricity for a long time, if care
be taken to place it upon non-conductors. iEpinus found it
electric after an interval of six hours*. He adds in a foot-
note, " These facts, as stated by JEpinus, if accurate, seem in-
consistent with the statement of Canton and Becquerel, that
the electricity is only developed whilst the stone is changing
its temperature." A statement of Dr. Brewster's might also
appear to support the views of iEpinus, and by opposing that
of Becquerel, leave the question still undecided. He men-
tionsf that a slice of tourmaline cut transversely to the axis
of the crystal, and placed on a plate of glass heated to 212°,
adhered to it for six or eight hours, even when the glass was
uppermost, the electricity of the tourmaline thus supporting-
its own weight.

The experiment which I am about to describe will, I think,
set at rest the question, and is in fact capable of showing
within a few minutes, and in a very pleasing manner, the
most essential facts of the relation of the electricity to tempe-
rature. M. Becquerel found that when a crystal of tourma-
line was heated to 212°, its electricity was inappreciable so
long as the temperature remained stationary ; but that when
placed in a cooler medium, the intensity of the electricity was
not, as might have been expected, proportional to the rapidity
of the change of temperature, which of course would corre-
spond to the period at which the temperature was highest,
but, on the contrary, arose gradually to a maximum, when the
tourmaline was about half way cooled to the temperature of
the apartment; then gradually diminishing, redescended to
zero when it reached that point. This remarkable result
M. Becquerel obtained by suspending the crystal horizontally
by a fibre of silk under a glass cover, the temperature of the
air in which he had the means of regulating ; he then applied
to the extremities of the crystal, wires from the opposite poles
of a dry pile, and, counting the number of oscillations made
by the tourmaline, deduced the intensity.

The form of the experiment which I have contrived, and
which bears out M. BecquerePs conclusions, gives the same

• p. 478. f Edinburgh Journal of Science, vol. i. p. 211.

Tourmaline and other* Minerals when exposed to Heat, 135

results with great elegance and simplicity, without attempting
to indicate the precise temperature of the stone at any period,
which, whilst the heat of the medium in which it is placed
changes, can only be by M. Becquerel's experiment an ap-
proximation, since the interior of the crystal must at any mo-
ment have a different temperature from its surface.

I employed a simple form of Coulomb's electrometer,
which I constructed for
the purpose with little
difficulty. A flat-shap-
ed bottle A B, having
a wide tubulature at C,
was provided. Fitted
to the neck is a tube
D, plugged at top by a
cork F, through which
passes a crooked wire
f> for the purpose of
regulating a fibre of
raw silk supporting the
needle of gum-lac e, one
end of which is termi-
nated by the disk g, of
gilt paper. The object
to be examined is intro-
duced through the tu-
bulature C, the disk
having previously been
charged with vitreous
or resinous electricity ;
and the repulsions oc-
casioned by the presence of the body under experiment are
measured with sufficient exactness by the deviation of the
needle reckoned on the divided circle of paper ik, I may
add, that the graduated circle H at the top of the glass tube
is employed to measure any required torsion of the silk fibre
produced by causing the cork F to revolve. By means of
this simple apparatus, I obtained results of greater accuracy
than my objects generally required*.

Upon presenting to the electrometer, which is quite an in-
sulator, an energetic crystal of tourmaline (which should not

* It is surprising that Coulomb's instrument has not been more employed
in this inquiry. Becquerel seems only to have used it once, and Dr. Brew-
ster had recourse to the laborious and unsatisfactory method of causing
pyro-electric crystals to lift fragments of the Arundo fhragmites, which can
give no comparative results.

1 36 Prof. Forbes's Experiments on the Electricity of

be too thin), heated to a considerable temperature, the gilt
disk being charged with the same electricity as is acquired in
cooling by the pole of the crystal presented, the following
results appear : At first the tourmaline exerts no influence
whatever; but after its temperature has begun to fall, the
repulsive power is gradually developed, and the gilt disk
slowly recedes as the increasing force appears : the recession
becomes very minute, and at length reaches a maximum, at
which the needle remains for a time stationary. Soon, how-
ever, a diminution of repulsion takes place ; the disk reap-
proaches its original point of rest; and, if left long enough,
will return to the zero point precisely opposite the crystal,
which then, as at first, produces no action whatever. It is un-
necessary to point out how completely this verifies M. Bec-
querel's views, and demonstrates that, as soon as the tempera-
ture completely ceases to change, not the minutest vestige
of electricity remains, though the insulation throughout should
be maintained as completely as possible. This I generally
accomplish by heating and handling the crystal in glass test-
tubes.

With regard to Dr. Brewster's remarkable experiment, it
partakes, I suspect, of a partly different class of phasnomena.
It occurred to me that it might, perhaps, if confirmed, be ex-
plained thus: — The slice of tourmaline may be considered, in
some respect, as an electrical coating to the glass. Suppose
that the tourmaline and the glass are heated together, and
that the side of the slice next the pole of the crystal, assuming
vitreous electricity by cooling, is next the glass. Let the other
side of the glass (which we shall call the second surface) com-
municate with the table or any other conductor; by the law
of Induction, then, it will assume resinous electricity, the first
surface repelling the vitreous. Conceive the glass plate now
to be insulated, we shall then have this state of things: — the
surface of the tourmaYmefurthest from the glass, by its even
excitation, is resinously electrified, for we have supposed the
side which coats the first surface of the glass to be vitreous ;
the resinous electricity, which is insulated at the second sur-
face of the glass, is powerfully attracting the opposite electri-
city of the side of the tourmaline next itself, and prevents the
recombination which would otherwise take place with the
electricity of the other side or pole.

Having succeeded in repeating Dr. Brewster's experiment
with thin slices from a large crystal of black tourmaline, I
found these hypothetical views confirmed. Having heated a
slice cut transversely to the axis of the crystal, I laid it upon
a plate of cold glass with the side which became vitreously

Tourmaline and other Minerals when exposed to Heat. 1 37

electric during cooling uppermost; the adhesion was presently
complete, so that the glass could be held with the stone sus-
pended from its under surface. The other surface of the glass,
behind the tourmaline, being then touched with a minute disk
of gilt paper, insulated on a thin stick of gum-lac, and then
presented to the electrometer, resinous electricity was found
of considerable intensity, showing that a decomposition of
electricity had actually taken place at the second surface of
the glass, the resinously electric pole of the tourmaline form-
ing the coating of its first surface, thus attracting the vitreous
electricity of the second surface, and disengaging the resinous.
Hence it is easy to see, that if the tourmaline remains suffi-
ciently long warm to prevent the recombination of the electri-
cities of its two poles, until the disengaged electricity at the
second surface of the glass shall have been carried off by the
air or otherwise, recombination will be prevented, and the
electric state will become comparatively permanent.

The use of Coulomb's electrometer, in the manner I have
already described, affords an easy and general method of
comparing the electric intensities of different crystals. For by
measuring the maximum deviation produced by any specimen,
we obtain, wholly independent of the exact temperature, a
measure of its electric power, a measure independent of time,
and, as experience shows, little if at all affected by the precise
heat to which the crystal has at first been raised, at least within
moderate limits. That the experiment admits, even with the
most ordinary attention to collateral circumstances, of consi-
derable accuracy, I have proved by repeating the measures
of the intensity of a particular specimen several times in suc-
cession. It will at once occur, that a source of fallacy must
be guarded against in the loss of the electricity with which the
disk of the electrometer is charged, which, as it is constantly
diminishing by the contact of air, would give the intensities
last measured in a series of comparative experiments too
small. In favourable circumstances, and by allowing the disk
to remain some time charged before the series is commenced,
it is surprising how little this error amounts to. I have al-
ways, however, avoided it in practice, by repeating every
series of experiments in an inverted order, by which we ob-
tain two observations at equal distances from a mean state of
electric tension, the mean of which will give strictly compa-
rable results.

The principal application which I made of this method of
observing was to attempt to discover some relation between the
form and dimensions of crystals of tourmaline, and their elec-
tric power.

Third Series. Vol. 5. No. 26. Aug. 183*. T

1 38 Prof. Forbes' s Experiments on the Electricity of

M. Becquerel, in a second memoir on the Tourmaline,
published in 1828#, announced the rather extraordinary cir-
cumstance, that long tourmalines did not become at all electric
by heat, and that their facility of being excited was generally
inversely proportional to their length. Dr. Thomson, in his
work on Heatf, mentions the former assertion, and observes
that it is one which he has never had an opportunity of trying.
As my experiments have been generally made with black tour-
malines from Van Diemen's Land, some of which are of great
length, this point early occurred to me as one deserving of
investigation. As these inquiries seem at no period to have
excited much attention in this country, and as of late nothing
whatever has been done upon them, these observations may
prove the more interesting.

The longest tourmaline employed by M. Becquerel was'six
centimetres, or 3'2 English inches, in length, with a diameter
of about *08 inch. My largest tourmaline is 3*25 inches, or
almost precisely the same, with a diameter little different. In-
stead of finding this crystal " tout a fait refractoire," as M.
Becquerel describes his, it proved uniformly susceptible of
powerful excitement, under the very same treatment which I
was accustomed to use towards those of smaller dimensions.
The intensity too was very great, though more slowly attained
than in shorter ones. Various tourmalines, between two and
three inches in length, uniformly show great activity on being
removed from the heat to which they have been exposed, and
left to cool, when applied to the electroscope.

This discovery led me to some inquiry into the effect of di-
mension in modifying electric action. Here it is necessary to
draw a distinction between the case of excitation and the in-
tensity of the effect produced. M. Becquerel generally men-
tions the temperature at which electricity appeared : my in-
quiries have been directed to the maximum intensity of that
electricity when excited, which is in some respects the more
satisfactory information of the two. The determination of the
temperature, we have already seen, is a point of great uncer-
tainty, since every range of atoms, from the centre to the sur-
face, must have a different temperature. Of course, for the
reason, the maximum effect is the integral of an infinity of
variable forces.

Amongst many experiments on different groups of crystals,
I may mention the following as the best determined. Six tour-
malines, all 1*3 inch long, whose thicknesses, or areas of sec-
tion, were represented by the numbers 14-, 11, 7, 6, and 4, had

* Ann. de Chimie. t p. 477.

Tourmaline and other Minerals 'when exposed to Heat, 1 39

their maximum intensities measured. Two series of experi-
ments in a direct order, and two reversed, all gave the same
order of intensity for these specimens, which, instead of bear-
ing any direct proportion to the areas, as might have been ex-
pected, where the lengths were equal, gave the following ar-
rangement* in the order of intensities : 1, 2, 5, 4, 3, the
areas following the natural order of the numbers. Other series
being taken with sets of crystals 1*2 and 1*8 inches long, gave
similar indications of irregularity f; but the area of section has
so far a general influence, that where the differences are con-
siderable, the thickest crystal has almost universally the great-
est power. The relative forces are so connected that we can
hardly impute the irregularities to any general law : the dif-
ferences, as I shall immediately illustrate by reference to an-
other class of experiments, must in all probability be attributed
to a variable structure in specimens of the same mineral, as
well as in those of different species.

I took a crystal l£ inch long, and carefully determined
the intensity of its electricity, which, by a mean of three expe-
riments, gave 45° of deviation. I immediately broke it at one
fourth of its length from one end : the two portions being then
heated, and their intensities determined each three times, the
mean of the larger portion gave a deviation of 47°, of the
smaller 43°, the mean of which gives precisely the original
force. As far as intensity goes, the diminution of length would
not therefore appear to be favourable to the development of
electricity. With a view of procuring through a larger range
of dimension the influence of length alone, I selected a series
of tourmalines whose sections were as nearly equal as possible,
the diameter being about TVth inch, and one of which was the
very long crystal before mentioned. This experiment was
made with great care ; a direct and reversed series were taken,
and several of the determinations independently repeated.

* The best pair of series gave,

No. 1, Deviation 115°

•5

3, 0

4, 26

5, 39-5

Nos. Intensity. Intensity.

1*2 long. 1*8 long.

1 (thickest) 82° 54°

2 775 40

3 50 34

4 575 355

5 65

6 (thinnest) 34

T2

140 Prof. Forbes's Experiments on the Electricity of

The mean deviations of the needle of the electroscope will be
given in the following Table.

No. Length. Intensity.

1 325 inch 79°*5

2 2-10 82

3 1*60 60

4 1-5.5 60

5 1*35 89

6 1-19 68

We thus see that the long crystal holds a high place among
those of equal section with it, and we have at the same time
an additional proof of the native irregularities of different
crystals.

It is well known that the artificial arrangement which re-
presents best the pha?nomena of the tourmaline, is that of a
series of insulated plates of glass arranged parallel to one an-
other, suitably coated, and with the contiguous coatings con-
nected by tinfoil. If one end of this battery be charged from
an electrical source, while the other communicates with the
ground, the plates at one extremity will partake of an excess
of the electricity communicated, whilst those at the other will
have the opposite species in excess, and a large proportion of
the range in the centre will exhibit no traces of free electricity :
hence by shortening the pile (supposing the plates very nu-
merous), no change will take place in the intensity of the free
electricity, but the intensity will bear a direct relation to the
surface of the plates, or the section of the pile. So far analogy
supports the increase of intensity with the diameter of the tour-
maline; but when we come to consider the mode of charging,
it fails, and leaves us in great doubt as to whether the length
of a crystal, if its structure be perfectly uniform, should have
any influence or not. I have found short crystals of a consi-
derable area, and so formed as to have a large surface, per-
haps the most energetic.

The unequal temperature of the portion of any section pre-
vents, as I have already observed, all the parts from giving a
maximum intensity at once. This will diminish the total effect,
but as all the parts afford the same kind of electricity, the re-
sultant can never be null on this account. Therefore even if
the irregularities of amount did not compel us to admit innate
varieties of structure, or electric disposition in different spe-
cimens, stubborn facts must force us to some such conclusion.
In the course of my researches I have met with a crystal of
tourmaline * possessing no external irregularities of structure,

* It is No. 3. of the Series at the foot of p. 139.

Tourmaline and other Minerals when exposed to Heat. 141

(the terminations, however, of the crystal are not preserved,)
which has the singular property of presenting in cooling a
vitreous pole at both ends. Having ascertained this point, I
proceeded to examine the electricity of its parts by means of
Coulomb's Proof-plane, by which the electricity of any portion
is insulated and examined. As I expected, I found the cen-
tral portion of the crystal resinously electrified. This remark-
able fact is not unexampled. Haiiy has recorded the case
of a crystal of topaz which had a similar property, which as it
is analogous to known facts in the phaenomena of magnetism
and of double refraction, Dr. Brewster conceived that the
crystal of topaz was composed of two with the vitreous poles
in contact, as in that case resinous electricity was developed
at both ends. Be this as it may, the example of tourmaline
which I have cited proves that the junction of the separate
crystals, if such exist, may be imperceptible, and as the pro-
bability that such irregularity should exist, however caused, is
in proportion to the length of the specimen, this may perhaps
explain the want of excitability observed by Becquerel in very
long crystals.

The phaenomena of tourmaline, though entirely electric,
bear so strong an affinity to those of magnetism, that the study
of their relations must be considered extremely important. I
have therefore one remark to make upon an experiment which
Dr. Brewster thinks indicative of a "singular breach of analogy
between the distribution of the pyro- electrical and magnetical
forces." After observing that in the process of reducing a
magnet to powder, the coercive force employed effectually de-
stroys all trace of magnetism, he adds, that powder of tour-
maline is highly electric when placed on a glass and heated,
which is shown by its adhering in conglomerated masses, ex-
hibiting the appearance of viscidity when stirred. It appears
to me that this experiment does not go to show that tourma-
line in a state of excitation does not lose its electricity when
bruised in a mortar ; indeed, such an experiment it would be
impossible to perform. A tourmaline, when it is not changing
its temperature, is as inert as a bar of iron before it is mag-
netized ; the process of heating or cooling the one is precisely
equivalent to that of conveying magnetism by induction or
otherwise to the other. The powder of tourmaline is there-
fore analogous to the filings of iron, both being equally inert,
till the native electricity of the former, and the native magnet-
ism of the latter, is decomposed, when the result in both is per-
fectly identical.

I shall now only very briefly allude to the conclusions to
which some experiments on the electricity of other minerals

] 42 Prof. Forbes's Experiments on Tourmaline, tyc.

besides tourmaline have led me. I have applied Coulomb's
electrometer with perfect success to the examination of topaz,
boracite, and mesotype, which have all been long known to
possess electrical powers. In the case of these minerals, I
have been able to extend Becquerel's remarkable law of the
intensity of electricity rising to a maximum, when the speed of
cooling has become comparatively low, which has not before
been demonstrated for any mineral except tourmaline. Topaz
possesses the remarkable property of retaining its electricity
long after the temperature has ceased to change; probably the
decomposition being effected with greater difficulty, the recom-
bination requires more time than in the more excitable mine-
rals. To so great an extent does this take place, that though
the maximum deviation of the needle, in one instance amount-
ing to 115°, took place within a few minutes after the excited
mineral was presented to the electroscope, in twenty minutes it
was hardly diminished, in forty minutes it was still 95°, in
an hour 85° #. After a lapse of several hours it was still con-
siderably excited ; I obtained similar results with several cry-
stals. Probably in all minerals the difficulty of decomposition
and combination increases with the mass ; hence, slender cry-
stals are most easily excited, and the effect less permanent.
Keeping these facts in view, JEpinus's statement that the tour-
maline preserves its electricity, when insulated, for several
hours, will admit of easy explanation, by supposing that he
worked with large and difficultly excitable crystals, similar
to this one of topaz, which had at the same time a very high
degree of intensity.

With a large crystal of boracite, having about J inch
for the side of its cube, I obtained very analogous results.
When one of its four resinous poles was presented to the elec-
tromter in a warm state, the disk slowly and regularly receded
from zero as the cooling advanced, and in about ten minutes
reached its maximum duration, which indicated a high degree
of intensity. The diminution of electricity was very slow ; in
three quarters of an hour the disk had receded but a little way.
A small crystal of boracite being similarly treated, the maximum
was speedily gained, and the needle returned to zero in one
experiment in twenty minutes, in another in half an hour. The
electricity of the disk in these experiments was extremely
steady.

The acicular crystals of mesotype attain with the greatest fa-
cility a high degree of electrical excitement, so much so that it
required some attention to discover that the maximum inten-

* The disk during this time was of course slowly parting with its charge.

Zoological Society. 143

sity was not immediately gained. It lasted a short time, and,
as in the case of slender tourmalines, the needle rapidly re-
ceded, and in a short time returned to zero.

The very satisfactory results which I have obtained from all
these minerals give me great confidence in the aptitude and
accuracy of my simple apparatus ; and from the very con-
siderable intensity which I find them all to possess, I expect
to be able to estimate much smaller degrees of pyro-electricity
in other minerals, and in artificial crystals, than have yet been
attempted.

Should my first results have appeared interesting to the So-
ciety, I may perhaps at no distant time have the honour of
communicating my further progress in the inquiry.
Greenhill, January 2, 1832.

XXIII. Proceedings of Learned Societies.

ZOOLOGICAL SOCIETY.

1834. SPECIMENS and drawings were exhibited of a fresh-
March 1 1 . — ^ water Tortoise, forming part of the collection of Mr.
Bell, by whom it was described as the type of a new genus, for which
he proposed the name of

Cyclemys.

Sternum latum, testam dorsalem longitudine fere aequans, inte-
grum, solidum j testae dorsali ligamento squamato connexum.

Cyclemys orbiculata. Cycl. iestd suborbiculari, carinatd, postice
dentatd, fused; scutis sternijlavescentibus, fusco radiatim lineatis.

Long, dorsi, 8 unc. j lat. 7 j alt. 3.

Emys orbiculata, Bell.

Pullus. Emys Dhor, Gray, Syn. Rept., p. 20.?

Hab. in India.

Mr. Bell regards the Tortoise which he has thus characterized as
supplying a link in the connecting series of the land with the fresh-
water families which has hitherto been wanting ; and as especially
valuable in the natural arrangement, by the clue which it furnishes
to the correct location of the Indian forms of the genus Emys. It is,
indeed, most nearly related to Emys spinosa, and on a superficial ob-
servation might almost be referred to that species ; but on closer
examination it is found to differ from that Tortoise, not only specifi-
cally, but generically also : its sternal bones are permanently sepa-
rated from the dorsal ones, with which they are connected by means
of a ligament alone, similar to that which performs the same office in
Terrapene. From the Box- Tortoises, however, to which, in this point
of its structure, it is so closely related, Cyclemys is altogether distinct,
the whole of its sternum being entire, instead of having, as is invari-
ably the case in Terrapene, one or more transverse divisions of the
sternum itself, the lobes of which move as on a hinge. In Terr.
Europaa this mobility of the sternum exists in each lobe in a small
degree, combined with the ligamentous connexion of the sternal to

144? Zoological Society.

the dorsal bones. In Cyclemys the whole sternum moves together,
though very slightly.

The transition from the land to the freshwater Tortoises may con-
sequently be regarded as commencing in Terrapene 5 passing through
Terr. Europeca to Cyclemys orbiculata ; and thence through the In-
dian forms of Emys, which so closely resemble the latter species, to
the other forms of Emys i the natural series of connexion between the
Testudinidte and the Emydidce being thus completed.

The exhibition was resumed of the new species of Shells contained
in the collection of Mr. Cuming. Those now exhibited were accom-
panied by characters by Mr. G. B. Sowerby, and consisted of species
and varieties additional to those previously characterized by Mr. Bro-
derip, (Lond. and Edinb. Phil. Mag., vol. iii. p. 69.) of the genus
Conus : viz. Con. Algoensis, Aulicus (Far. roseus), Nussatella,tendi'
neus, Luzonicus, brunneus, pulchellus, Diadema,ferrugatus, and Rega-
inat is.

A specimen was exhibited of the Musk Duck of New Holland,
Hydrobates lobatus, Temm. It had recently been presented to the
Society by Lieut. Breton, R.N., Corr. Memb. Z. S., who entered into
some particulars respecting its habits. He stated that these birds are
so extremely rare, that he saw only three of them during his various
excursions, which extended over twelve hundred miles of country.
He has never heard of any instance in which more than two were
seen together. They are met with only on the rivers, and in pools
left in the otherwise dry beds of streams. It is extremely difficult to
shoot them, on account of the readiness with which they dive ; the
instant the trigger is drawn, the bird is under water.

Some observations by Dr. Hancock on the Lantern fly and other
Insects of Guiana were read.

The writer concurs with M. Richard and M. Sieber in regarding
as erroneous the statement of Madame Merian, that the Lantern-fly>
Fulgora lanternaria, Linn., exhibits at night a brilliant light, and
remarks that the whole of the native tribes of Guiana agree in treating
this story as fabulous : it seems to be an invention of Europeans de-
sirous of assigning a use to the singular diaphanous projection, re-
sembling a horn lantern, in front of the head of the insect. He also
states that the Fulgorce rarely sing.

The insect whose song is most frequently heard in Guiana is the Ci-
cada clarisona) the Aria-aria of the Indians, and Razor-grinder of the
Colonists : in the cool shade of the forests it may be heard at almost
every hour of the day ; but in Georgetown its song commences as
the sun disappears below the horizon. At Georgetown this Cicada
was never heard in 1804, when Dr. Hancock first visited the place ;
but it is now very common, probably in consequence of the shelter
afforded by the growth of many trees and shrubs in the gardens which
have since been formed there. The sound emitted by it is M a long,
continuous, shrill tone, which might be compared almost to that of a
clarionet, and is little interrupted, except occasionally by some vibrat-
ing undulations."

March 25. — A specimen was exhibited of an Albatross presented

Zoological Society. 145

to the Society by Lieut. Breton, Corr. Memb. Z. S., whose principal
object in calling the attention of the Society to it was to mention
that, being unprovided at the time at which the bird was killed with
any of the ordinary preserving powder or soap, he had used for its
preservation a mixture of Cayenne and black peppers with snuff and
salt. The skin, well rubbed with this mixture, was brought through
the intertropical regions in an ordinary trunk, affording free access to
insects, and arrived in England uninjured. Lieut. Breton conceives
thut it may be advantageous to collectors to be made aware that
the preservation of skins can be secured by articles so constantly at
hand as those which he employed in this instance.

The exhibition was resumed of the new species of Shells forming
part of the collection made by Mr. Cuming on the western coast of
South America, and among the islands of the South Pacific Ocean.
Those brought on the present evening under the notice of the So-
ciety were accompanied by characters by Mr. G. B. Sowerby, and
consisted of five species of the genus GastrochjEna : viz. Gastroch.
ovata, truncata, brevis, rugulosay and hyalina.

A Note was read from Mr. Gray, giving an account of the arrival
in England of two living specimens of Cerithium armatum, which had
been obtained at the Mauritius, and had been brought from thence in
a dry state. That the inhabitants of land Shells will remain alive
without moisture for many months is well known : he had had occa-
sion to observe that various marine Mollusca will also retain life in a
state of torpidity for a considerable time, some facts in illustration of
which he had communicated at a recent Meeting of the Society (Lond.
and Edinb. Phil. Mag., vol. iii. p. 66.) : the present instance included,
however, a torpidity of so long a continuance as to induce him to
mention it particularly. The animal, though deeply contracted within
the shell, was apparently heal thy> and beautifully coloured. It emitted
a considerable quantity of bright green fluid, which stained paper of a
grass green colour : it also coloured two or three ounces of pure water.
This green solution, after standing for twelve hours in a stoppered
bottle, became purplish at the upper part ; but the paper retained its
green colour though exposed to the atmosphere.

The Secretary mentioned an instance of the arrival in this country
of a living Cerithium Telescopium, Brug., brought from Calcutta, in
company with some small Paludina, which also reached England
alive : these Mollusca were, however, kept in sea water frequently
changed. The Cerithium was placed by Mr. G. B. Sowerby, for dissec-
tion, in the hands of the Rev. M. J. Berkeley and G. H. Hoffman,
Esq., who have prepared a paper on its anatomy for the forthcoming
No. of the ! Zoological Journal' : it will be illustrated by a series of
figures, which were exhibited to the Meeting. It is worthy of re-
mark, that the spirit in which this animal was immersed for the pur-
pose of killing it, and in which it was kept for some weeks, became of
a dark verdigris colour.

Dr. Weatherhead exhibited two young Ornithorhynchi preserved
in spirit, which he had recently received from New Holland, and
stated his intention of presenting one of them to the Society's Mu-

Third Series. Vol. 5. No. 26. August 1834. U

146 Zoological Society.

seum. The smallest of them is about two inehes in length ; the
largest about four. Both are destitute of hair; and in both the
eye-lids are closed. In the smaller one there is a vestige of an
umbilical slit.

The larger of the two is one of those which were kept in captivity,
with their dam, by Lieut, the Hon. Lauderdale Maule, as noticed
in a communication read at the Meeting of the Committee of Sci-
ence and Correspondence of this Society on September 11, 1832,
(Lond. and Edinb. Phil. Mag., vol. ii. p. 71.) With it was exhibited
the dried skin of the dam, to which the mammary glands, largely
developed, had been left adhering.

A Note from Lieut. Breton, Corr. Memb. Z. S., was read, giving
an account of an Echidna, which lived with him for some time in New
Holland, and survived a part of the voyage to England. The animal
was captured by him on the Blue Mountains : it is now very uncom-
mon in the colony of New South Wales. He regards it as being of
its size the strongest quadruped in existence. It burrows readily,
but he knows not to what depth.

Previously to embarkation this individual was fed on ant-eggs and
milk, and when on board its diet was egg chopped small with liver
and meat. It drank much water. Its mode of eating was very curi-
ous, the tongue being used at some times in the manner of that of
the Chameleon, and at others in that in which a mower uses his
scythe, the tongue being curved laterally, and the food, as it were,
swept into the mouth : there seemed to be an adhesive substance on
the tongue, by which the food was drawn in. The animal died sudden-
ly off Cape Horn, while the vessel was amidst the ice ; perhaps in con-
sequence of the cold, but not improbably on account of the eggs with
which it was fed being extremely bad.

Lieut. Breton agrees with MM. Quoy and Gaimard in believing
that little difficulty would be experienced in bringing alive to Europe
the Echidna or Porcupine Ant-eater of New Holland. He suggests
the following plan.

Previously to embarkation the animal should gradually be weaned
from its natural food of ants, which may be done with great facility
by giving it occasionally ants and ant-eggs, (the last is, in fact, more
properly speaking, its common food,) but more generally milk, with
eggs chopped very small, or egg alone. When on board ship it should
be kept in a deep box, with strong bars over the top, and a door. It
is requisite that the box or cage be deep, because the animal con-
stantly tries its utmost to escape ; and possessing very great strength,
is liable to injure itself in its exertions to force its way through the
bars. The effluvia arising from its excrement are so extremely fetid,
that it cannot be kept altogether in a cabin, unless the cage be fre-
quently cleaned. While this is being done, the Echidna may be al-
lowed its liberty, but must be narrowly watched, or it will certainly
go overboard. It is absolutely necessary that the eggs which are to
constitute its food during the voyage be as fresh as possible : they can
be preserved in lime water. If milk is not to be procured, water must
be supplied daily ; and egg and liver (or fresh meat) cut small, should

Zoological Society. 147

be given at least every alternate day ; but, when the weather will per-
mit, it should be fed once a day. Half an egg (boiled hard) and the
liver of a fowl or other bird will suffice for a meal. Finally, the ani-
mal should be kept warm, and well supplied with clean straw. It will
be as well to nail two or three pieces of wood (battens) across the
floor of the cage, to prevent the animal from slipping about when the
ship is unsteady.

April 8. — A Letter was read, addressed to the Secretary by John
Hearne, Esq., Corr. Memb. Z. S., dated Fortau Prince, Feb. 15, 1834.
It accompanied a present to the Society of a pair of the common Goats
of Hayti ; referred to various Birds which it is the intention of the
writer to forward when the season is more advanced $ and gave some
particulars of a bird known in the island by the name of the Musician,
respecting which Mr. Hearne hopes to obtain, in the course of a jour-
ney which he projects into the higher lands of the interior, more full
information than he at present possesses.

Some extracts were read from a Letter, addressed to Mr. Yarrell
by Dr. A. Smith, Corr. Memb. Z. S., dated Cape Town, Jan. 12,
1834. It refers to the projected expedition from the Cape of Good
Hope into the interior of Africa, which it is the intention of the writer
to accompany. It is designed to proceed directly northward from
Latakoo $ and Dr. Smith anticipates in this new field numerous ad-
ditions to his Zoological stores : along the eastern and western coasts
he has already penetrated to a considerable distance. Speaking of
the Rodentia, so numerous in Southern Africa, he mentions as col-
lected by him, in his late visit to Port Natal and the Zoola country,
a second species of his genus Dendromys. He also notices a new
species of Chrysochloris obtained by him in the same country.

At the request of the Chairman, Mr. Gould exhibited an exten-
sive series of Birds of the genus Trogon, Linn., comprising twenty-
five species. The greater number of them form part of the Society's
Museum, and the others were derived from his own collection.

He pointed out the distinguishing marks of the two sections of
the genus, one of which is confined to America, while the other
inhabits the Old Continent. He also pointed out among the species
exhibited there which he regarded as hitherto undescribed ; these he
named and characterized as Trogon erythrocephalus, Malabaricus,
and elegans.

Mr. Bennett briefly recapitulated the facts and reasonings which
have from time to time been brought before the Society on the sub-
ject of the abdominal glands of the Monotremata, regarded by Meckel
and by Mr. Owen as mammary, and by M. GeofTroy- Saint Hilaire
as connected with a peculiar function, to which, however, differ-
ent results have been attributed by that learned zoologist at various
times*. The object of the recapitulation was to introduce an abstract
of a recent Memoir by M. Geoftroy-Saint- Hilaire, " On the structure
and use of the Monotrematic glands, and particularly on those glands

* See Lond. and Edinb. Phil. Mag., vol. i. p. 384 ; vol. ii. p. 71 ; vol. iii.
pp. C2. 301 ; vol. iv. p. «r>4; and the present article, p. 145.

U2

148 Zoological Society.

in the Cetacea." In this Memoir the author regards the mammary
glands of the Cetacea, so analogous in structure to those of Ornitho-
rhynchus and Echidna, as having a function similar to that which he has
attributed to these latter : he assumes that the fluid secreted by them
is not milk but mucus, and that this mucus is not sucked by the
young, (whose organs of deglutition he describes as being unfitted
for sucking,) but is ejected by the mother into the water, the element
in which they dwell, where, by imbibition of a portion of the water,
it becomes thickened, and, floating by the mother's side, is devoured
by the progeny.

M. GeofTroy has subsequently changed his opinion as to the na-
ture of the fluid secreted by the nutrient glands of the Cetacea. He
had had an opportunity of examining these glands in some Porpoises,
and had found the secretion to be actually milk. He still, however,
maintains that the young of the Cetacea do not suck, but that the
mother ejects the nutritious fluid from the milk receptacle into the
mouth of her young.

April 22.— Some Notes by J. B. Harvey, Esq., Corr. Memb. Z. S.,
were read : they accompanied a collection of Shells and Crustacea
made by the writer on the coast of Devonshire, near Teignmouth.
The several specimens were exhibited.

Among them were numerous individuals of Cyprcea Pediculus, Cyp.
bullata, and Cyp. Arctica. Of the former there are two varieties,
one spotted and the other without spots. The spotted variety, Mr.
Harvey states, is generally smaller than the plain one, and is less pro-
duced on one side near the apex.

Cyp. bullata is found in the same localities as Cyp. Pediculus, but
it may be doubted whether it is the young of that species : it is so
comparatively rare, that Mr. Harvey has dredged up only six speci-
mens of it, while he has collected more than a hundred of Cyp. Pedi-
culus : he possesses, moreover, young individuals of Cyp. Pediculus
of smaller size than specimens of Cyp. bullata. In the latter the
whorls are more produced at the apex, and the shell is so delicate as
to be broken by even a slight fall.

On Cyp. Arctica Mr. Harvey remarks, that although its size and
appearance are in favour of its being a young shell, he hesitates in
referring it to the immature condition of the unspotted Cyp. Pedicu-
lus : his principal ground for doubt is the extreme rarity of Cyp.
Arctica. He inquires, however, whether the young animal may not,
perhaps, live deeply imbedded in the sand for a certain period before
it comes to the surface, and thus generally elude the search of the
conchologist until its shell becomes matured?

With the Shells Mr. Harvey had transmitted to the Society living
specimens of Caryophyllia Smithii, Brod., the Torbay Madrepore,
whose habits were described by Mr. De la Beche in the ' Zoological
Journal ' a few years since : these individuals died on the journey.
They are attainable only at the lowest spring tides. They may be
kept alive in sea water, changed every second or third day, by feed-
ing them with a very small piece of fresh fish scraped, and deposited
with a quill upon the animal, by which it is sucked in in a manner

Zoological Society, 149

exactly similar to that of Polypi. The colours of some individuals
are very vivid j and among these green, blue, and blueish grey are
the most predominant. Adhering to the Caryophyllia is occasionally
found the Pyrgoma Anglicum> Leach, which appears to occur in no
other situation.

At the request of the Chairman, Mr. Thompson of Belfast exhi-
bited an immature specimen of the long-tailed Manis, Manis tetra-
dactyla, Linn., for the purpose of showing that when very young,
(the present specimen being but ten inches in length,) the animal is
as thoroughly armed, both with respect to scales and spines, as the full-
grown one. The specimen was also considered by Mr. Thompson as
interesting on account of its locality, it having been obtained in
Sierra Leone.

Mr. Thompson also read the following notice of the Cuckoo, Cuca-
lus canorus, Linn., copied from his Journal, under the date of 28th
May, 1833.

" On examination of three cuckoos to-day, which were killed in
the counties of Tyrone and Antrim within the last week, I found
them all to be in different stages of plumage : one was mature ; ano-
ther (a female) exhibited on the sides of the neck and breast the red-
dish-coloured markings of the young bird, the remainder of the plu-
mage being that of maturity j the third specimen had reddish mark-
ings disposed entirely over it, much resembling the plumage described
by M. Temminck as assumed by ' les jeunes tels qu'ils emigrent en
automne', (Man. d'Orn., torn. 1. p. 383,) but having a greater pro-
portion of red, especially on the tail coverts, than is specified in his
description of the bird at that age. This individual proved, on dissec-
tion, to be a female, and did not contain any eggs so large as ordi-
nary sized peas. The stomach, with the exception of the presence of
some small sharp gravel, was entirely empty, and was closely coated
over with hair."

Attention was called to the stomach of one of these birds, that the
hair with which it is lined might be observed. From its close adhesion
to the inner surface of the stomach, and from the regularity with
which it is arranged, Mr. Thompson was at first disposed to consider
this hair as being of spontaneous growth j but part of the stomach
having been subjected to maceration in water, and afterwards viewed
through a microscope of high power, the hairs proved, to the entire
satisfaction of Mr. Owen and himself, to be altogether borrowed from
the larvce of the Tiger-moth, Arctia Caja, Schrank, the only species
found in the stomach of the bird in various specimens from different
parts of the country which were examined by Mr. Thompson in the
months of May and June, 1833.

Mr. Thompson also read a Catalogue, with incidental notices, of
Birds new to the Irish Fauna. He prefaced his list by remarking
that he did not bring them forward as unrecorded, without having
previously consulted every work in which he was aware that the birds
of Ireland are either particularly described or incidentally noticed ;
including the Statistical Surveys of the Irish counties, which contain,
in several instances, Catalogues of the Birds that have been observed
in them. The Catalogue is given in the Proceedings of the Society.

150 Intelligence and Miscellaneous Articles.

Mr. Owen read a Paper " On the Structure of the Heart of the
Perennibranchiate Amphibia, or Reptiles douteux of Cuvier."

He briefly noticed the progressive discoveries relating to the heart
of Reptiles which have been made since the time of Linnaeus, and
which have successively rendered inapplicable to the Saurian s, Cheloni-
ans, and Ophidians, the phrase " Cor uniloculare, uniauritum", applied
to the whole of the Reptilia in the f Systema Natures'. He alluded to
the researches of Dr. Davy and M. Martin St. Ange on the structure
of the heart in the Caducibranchiate Amphibia, from which it appeared
that two auricles were appended to the ventricle in those Reptiles, as
well as in the higher orders above mentioned. He then proceeded to
give the results of an examination of the hearts of specimens of Am-
phiuma, Cuv., Menopoma, Harlan, Proteus, Schreib., and Siren, Linn.
He selected the heart of the Siren lacertina as the subject of detailed
description, considering that the genus Siren, in combining with per-
sistent external branchice a limited number of extremities, exhibits the
simplest form of the Amphibious Reptile.

The heart in this species consists of three distinct cavities, as in the
higher Reptilia, viz. of two auricles and one ventricle. The auricles
appear to form externally one large and remarkably fimbriated cavity,
situated behind, and advancing forwards, on both sides of the ventricle
and bulbus arteriosus. The venous blood is poured into a large mem-
branous sinus by one posterior and two anterior ven<e cava prior
to passing into the auricle. The conjoined trunk of the pulmonary
veins appears also to enter this sinus, but it passes through without
communicating with that cavity, and terminates in a small separate
auricle, which opens into the ventricle by an orifice distinct from, but
close to, the orifice of the right auricle. In the ventricle a rudimen-
tary septum was noticed as affording an indication of a type of forma-
tion superior to that of Fishes. In the bulbus arteriosus a longitudinal
projection appears as a commencing division of the single artery,
which is given off from the ventricle.

The differences in the structure of the preceding parts, and in the
origin and distribution of the different vessels exhibited by the other
genera of Perennibranchiata, were successively noticed ; and the affini-
ties indicated by these modifications to the Caducibranchiate Reptiles
on the one hand, and to the Cartilaginous Fishes on the other, were
also pointed out.

The Paper was illustrated by drawings of the structures described
in it.

XXIV. Intelligence and Miscellaneous Articles.

ON SOME NEW COMBINATIONS OF PLATINA. BY M. DGEBEREINEI?.

IF solutions of muriate of platina and carbonate of soda, the latter
being in excess, be mixed and exposed for some days to the sun,
or a temperature of 212°, there is gradually formed a precipitate, of
a chrome yellow colour, which is partly in small crystals, composed
of soda and oxide of platina, in proportions not yet ascertained: these
contain from 0*5 to 1 per cent, of chlorine. I consider this pre-
cipitate as a salt, which I shall call provisionally platinatc of soda,

Intelligence and Miscellaneous Articles. 151

iD

the symbol Na PR When heated to redness, it gives at first a
quantity of water, then acid, and becomes black : the soda which
it contains may then be separated by water. The black powder
which remains appears to be a mixture of platina and oxide of pla-
tina, for it inflames a current of hydrogen passed over it, and gives,
with muriatic acid, muriate of platina, and a black powder, insoluble
in it, which becomes red in a detonating mixture of gases, and of a
grayish white colour. With oxalic acid this substance acts as a
mixture of oxide and of metal.

Acetic acid separates from the salt in question all the soda which
it contains, and leaves oxide of platina, of an ochre yellow colour,
A small portion of this oxide dissolves in the acid, without impart-
ing any colour to it ; from which it appears that oxide of platina
dissolves with difficulty, or scarcely at all in acetic acid. It may
be objected to this observation that muriate of platina is not pre-
cipitated by acetate of soda, and that the mixture of these salts in
solution suffers no alteration, either by heat or solar light; but al-
cohol reduces the oxide which it contains to the spongy state, which
does not happen unless it is combined with acetic acid, for the mu-
riate is never reduced so quickly and so perfectly by alcohol.

Formic acid decomposes platinate of soda completely at a gentle
heat, that is to say, all the oxide of platina is reduced, and a rapid
disengagement of carbonic acid gas takes place. Eight grains of
the salt, dried at 212°, gave with this acid five cubic inches of car-
bonic acid gas, consequently 105 grains of oxygen are combined
with platina in eight grains of the salt.

The metal, reduced to the state of spongy platina, becomes
instantly red hot when put upon printing paper slightly impregnated
with alcohol.

Oxalic acid dissolves platinate of soda when heated, with the de-
velopment of carbonic acid. A dark-coloured liquid is obtained,
which, on cooling, at first becomes green, and afterwards of a deep
magnificent blue colour : there are soon formed in it small needle-
shaped crystals, of a deep copper red colour, and a metallic lustre,
which are protacetate of platina Ft O. These crystals, when heated,
detonate : water separates, and carbonic acid is produced. The solu-
tion separated from the crystals is of a pale blue colour -, diluted
with water it becomes yellow, and by evaporation it becomes of a
deep blue colour.

Dilute nitric acid readily dissolves platinate of soda ; the solution
is of a deep yellow colour. In a solution of nitrate of silver it gives
a yellow precipitate, which is totally dissolved by nitric acid if the
salt is free from chlorine j it is probably a nitroplatinate of silver.

If muriate of platina be mixed with a little cream of lime, then
with a large quantity of lime water, and the filtered solution be ex-
posed to the sun, it quickly becomes as turbid as milk, and after
some hours it forms a flaky precipitate, which, after being boiled, is
a yellowish white powder. According to Herschel *, this product is

* Sir John F. W. HerschePs observations on this substance will be
found in Lond. and Edinb. Phil. Mag , vol. i. p. 59. — Edit.

] 52 Intelligence and Miscellaneous Articles.

platinate of lime ; but according to my process for obtaining it, it is
a compound of chloride of platina and platinate of lime (Pt Ch*

-f Ca Pt')-

If this compound be heated in a platina crucible to bright red-
ness, it loses about 2.5 per cent., being water and a part of the
oxygen combined with the platina. It becomes a deep violet-coloured
powder, which becomes very hot when sprinkled with water, and
when treated with dilute nitric acid, &c , is decomposed into muriate
of lime, lime, and oxide of platina, of a deep violet colour.

This oxide is, I believe, the protoxide of platina (Pt), the base of
the coppery oxalate already mentioned. This oxide does not dis-
solve in any oxyacid, but it combines by long digestion with oxalic
acid. When treated with formic acid it is reduced to spongy pla-
tina, and evolves carbonic acid tumultuously, and in such quantity
that its volume shows the quantity of oxygen contained in the prot-
oxide. Eight grains of this oxide dried at 212°, being reduced by
formic acid, gradually heated to ebullition, gave such a quantity of
carbonic acid as showed its composition to be 92204? metal, and
7*796 oxygen: according to Berzelius, the protoxide of platina con-
tains 7'6 per cent, of oxygen. This difference probably arises from
the circumstance of the oxide which I examined, and that once only,
containing a small quantity of peroxide, or that the protoxide of
Berzelius contained, as asserted by Liebig, some chlorine. — Ann.
de Chim. et de Phys.} torn. liii. p. 204.

ON THE ROTARY MOTION OF CAMPHOR. BY M. CHARLES
MATTE UCCI.

The phaenomena exhibited by camphor, when put upon water,
have been long known, and several philosophers have examined
them ; but if they are generally agreed as to the circumstances of
these curious phaenomena, this is not the case as to their cause.
Thus, it has been said they were owing to the development of elec-
tricity, or to the solution of camphor, and lastly, to the evaporation
of the camphor and water. It is easy to prove that it is not owing
to the solution of the camphor in the water, for there are several
substances which are much more soluble, but which do not turn
when placed on water. Nothing indicates the development of elec-
tricity, and in this case it is not conceivable how it could produce
the effect. The evaporation of water ought not to be considered in
the explanation of the phaenomena. It is therefore entirely to the
evaporation of the camphor and its solution in the strata of water
which surround it, that the cause of the motion must be attributed ;
and it is this opinion which I propose to develop and maintain.

Potassium is a substance which, when thrown on water, resem-
bles camphor in the phaenomena it produces : in this case it is to the
disengagement of hydrogen and the vapour of water that the rapid
movement must be attributed. It is even possible to imitate this
rotation in a more simple manner ; for this, it is sufficient to throw
a small piece of red-hot charcoal upon water, or a very fine metallic

Intelligence and Miscellaneous Articles. 153

'o

wire, suspended and previously heated. The motion, in this case,
is produced simply by the vapour of water disengaged around the
floating body. It is this hypothesis which very readily explains the
suspension of rotation when a drop of oil is thrown on the surface
of the water, or when it is covered with a plate of glass.

The following are the most convincing facts in favour of this ex-
planation of the motion of camphor. I took rather a large piece of
it, in order that when put upon water its motion might be very slow.
I afterwards put the glass in which the experiment was made under
the receiver of the air-pump and exhausted it. I then observed that
the movements of the camphor, which were at first scarcely per-
ceptible, become more rapid, and that they ceased when the action
of the pump was stopped. On allowing the air to enter, the rota-
tion occurred for some seconds, which was undoubtedly occasioned
by the agitation produced by the reentering air. Lastly, and it is
the most unexceptionable proof, I have observed these phenomena
of rotation on water in all volatile bodies. I took raspings of cork
and impregnated them with sulphuric aether : when placed upon
water these small light bodies turned very rapidly. If it be wished
to cause this rotation to continue for a long time, it is sufficient to
immerse a wire in sether, and to make the other end touch the sur-
face of the water ; the aether descends as by a syphon, and the mo-
tion is continued.

It is, then, I think, proved that the rotation of volatile bodies is
owing to the currents of their vapours. I will add a word respect-
ing the well-known phaenomenon produced by a stick of camphor
immersed in water : I mean that of its being cut precisely according
to the line which touches the exterior surface of the liquid. It is
easy to prove, that of all the strata of water which are in contact
with the camphor, it is in the upper that the solution is greatest. In
fact, camphor dissolves in small quantity in water, but it is only at
the surface that the dissolved camphor can evaporate : this water
then dissolves a fresh portion, and so on repeatedly. When this
solution is prevented, the phaenomenon ceases to be produced. If a
stick of camphor be placed in a concentrated solution of potash,
and another in water, the latter is cut in two in three or four days,
and the other is not at all attacked. — Ann. de Ckim. et de Phys.,
torn, liii.p. 216.

ON MARGARON, STEARON, AND OLEON.

M. Bussy prepared margaric acid by distilling suet, and purifying
the product by pressure and crystallization in alcohol : it melted at
131° Fahrenheit. This acid was preferred to that obtained by sa-
ponification, because the margaric acid contained no stearic acid,
and because it is more easily purified from the fluid products with
which it is mixed.

A quantity of this acid was mixed with a quarter of its weight of
lime, and distilled in a retort. First a quantity of water came over,
and then a soft mass, from which there is obtained, by pressure, a
matter similar to that which the suet furnishes. The last portions

Third Series. Vol. 5. No. 26. Aits. 1834. X

154 Intelligence and Miscellaneous Articles,

of the acid undergo a more complete decomposition, for towards
the end, the products are coloured and empyreumatic, and there re-
main in the retort a mixture of lime and carbonates and a small
quantity of charcoal, which renders them black: 40 parts of mar-
garic acid, treated in this manner, yielded 28 parts of a slightly
yellowish solid, which soiled paper when pressed, and yielded 22
parts of dry matter, which melted at 165° Fahrenheit. It was re-
peatedly treated with alcohol of sp. gr. 0*837. After 11 digestions
the fusing point of the last portion dissolved was 171°.

The substance thus obtained is of a pure white, brilliant and
pearly when withdrawn from the alcohol from which it is precipi-
tated. It fuses, as already mentioned, at 171°; crystallizes irregu-
larly on cooling ; and in appearance resembles margaric acid, or
spermaceti. It is a nonconductor of electricity, and becomes
strongly electrical by friction or pressure : when triturated in an
agate mortar it often rises to the edges of the mortar, or to the
pestle, and adheres to the paper used in removing it, If it be heated
in a retort it boils, and distils without undergoing any notable
change, and without leaving any residue. At a Jiigh temperature
it burns with a very bright flame, and without smoke : paper or a
cotton wick impregnated with it, burn in the same manner.

It dissolves in boiling alcohol of 0 837, but rnuch less abundantly
than margaric acid, requiring 50 times its weight. On cooling, the
greater part of it separates, and water precipitates it. It dissolves
in less than seven times its weight of alcohol of 0817 : the solution
solidifies on cooling. Hot sulphuric aether dissolves more than -^th
of its weight, the greater part of which precipitates on cooling. Hot
acetic aether dissolves it in large quantity, and on cooling a pearly
mass is obtained : oil of turpentine produces a similar effect. It
combines with camphor in all proportions: a strong and boiling so-
lution of potash has no effect upon it. By sulphuric acid it is black-
ened, and completely decomposed with the disengagement of sul-
phurous acid. One part of it slightly heated with two parts of sul-
phuric acid, first became of a red colour, afterwards brown, then a
deep black, and in a short time a coaly mass was obtained. Hot
nitric acid acted but slightly upon it: by the action of dry chlorine
gas, and at a low temperature, it was completely converted into a
colourless, transparent, viscid liquid.

This substance, which M. Bussy calls margaron, bears some
analogy to the paraffine of M. Reichenbach : it approaches it also in
composition, as will presently be seen ; but they differ in their melt-
ing point, margaron fusing at 171°, and paraffine at 111° Fahrenheit.
Secondly, sulphuric acid does not act upon, but completely decom-
poses margaron. By analysis it yielded

Carbon 83-34

Hydrogen 13*51

Oxygen 315

100-00
M. Bussy regards it as equivalent to margaric acid, less an
atom of carbonic acid.

Intelligence and Miscellaneous Articles, 155

Stearic acid, treated in the same manner, yielded a substance
which M. Bussy calls stearon, which resembles margaron in its ex-
ternal characters. When purified by crystallization in alcohol, it
melts at 182° Fahrenheit, and it is less soluble than margaron in al-
cohol and aether. It is composed of

Carbon 84-78

Hydrogen 1377

Oxygen 1*45

10000
It appears to be equivalent to stearic acid deprived of carbonic acid.
Oleic acid, treated in the same manner as the two preceding,
yielded also carbonate of lime as a residue, but the product distilled
was fluid from the commencement of the operation. This fluid was
not acid nor saponifiable, and appeared to be to oleic acid what
margaron and stearon are to the preceding acids. The difficulty of
obtaining pure oleic acid, and of separating oleon completely from
other liquid products, which the distillation may have yielded, has
hitherto prevented an analysis of it. — Ann, de Chim. et de Phys.,
torn. liii. p. 398.

SUPPOSED COMPOUND OF HYDROGEN AND PLATINA. BY M.
BOUSSINGAULT.

Berzelius (Chimie, torn. iii. p. 64.) mentions a supposed compound
of hydrogen and platina, which may be thus prepared : Dissolve equal
parts of iron and platina in aqua regia ; the solution, deprived of its
excess of acid, is to be precipitated by ammonia. The precipitate,
when washed and dried, is to be reduced by hydrogen gas, in a
glass tube heated to low redness : muriatic acid, muriate of ammo-
nia, and the vapour of water are given out. The gas is to be passed
until the tube cools. The residue in the tube is a mixture of platina
and iron, which acts strongly as a pyrophorus : it requires some
dexterity to put it into muriatic acid without its inflaming. The
acid dissolves the iron with an abundant evolution of hydrogen gas ;
there remains a black powder, which is very heavy, and which only
requires well washing.

This black powder, heated in an open vessel, inflames much below
a red heat : sometimes it deflagrates, and the matter is thrown out
in sparks; at other times the combustion takes place slowly, the
powder burning like amadou. When heated in a close vessel, a little
moisture appears on the cold part of it, and this circumstance gave
rise to the opinion of the existence of hydrogen in it ; but M. Bous-
singault considers it as unquestionably hygrometric moisture.

During combustion 311 parts of the powder increased in weight
to 314, a circumstance which rendered the presence of iron ex-
tremely probable ; but it is remarkable that the combustion occa-
sions no change in the appearance of the powder ; though it is no
longer combustible, and 311 of the black powder, treated with boiling
nitric acid, left 249 of finely divided platina : the acid contained only
peroxide of iron, which amounted to ^th of the powder. It is
therefore very probable that the ignition is owing to the combustion
of a part of the iron which is combined with the platina.

X2

156 Intelligence and Miscellaneous Articles.

To prove that it contained no hydrogen, the black powder was
mixed with peroxide of copper, and heated as in vegetable analyses ;
but the quantity of water obtained was such as to show that it could
not contain -j oVvth of its weight of hydrogen, and it is most pro-
bable that it did not contain any. On account of the difficulty of dry-
ing, the water was undoubtedly hygrometric. These experiments
appear sufficient to prove that the supposed hydruret of platina is
merely an alloy of iron and platina.

Descotils obtained from an alloy of platina and zinc, by means
of dilute sulphuric acid, a black powder, which inflamed below a
red heat. M. Boussingault found that it contained 31 per cent, of
zinc, and its weight after combustion increased like that of the alloy
of iron and platina. M. Boussingault proposes to examine, at a future
opportunity, the black scales which Davy obtained by treating an
alloy of platina and potassium with water, and which he considered
as a hydruret of platina. — Ann. de Chim, et de Phys., torn. liii. p. 44- 1 .

BORATES OF MAGNESIA. BY M. WOHLER.

The boracite is a well known crystallized mineral, composed of
boracic acid and magnesia. When solutions of borate of soda and
borate of magnesia are mixed, no precipitation takes place until the
mixture is heated, and then an abundant white precipitate is formed,
which redissolves as the solution cools.

A solution in which the crystals had redissolved was exposed for
several months to a temperature below 32° of Fahr. During this
exposure, fine radiated acicular crystals were formed, some of them
half an inch long • they were so slender that it was not possible to
determine their crystalline form. These crystals are transparent,
brilliant, hard and brittle, and perfectly insoluble in water, either
cold or hot. Muriatic acid when hot decomposed these crystals,
boracic acid being deposited on cooling ; when heated they became
opake and lost water. By analysis this salt yielded

Boracic acid 25*

Magnesia 16-67

Water 58-40

10007
The boracic acid and magnesia are in the same proportion as in
boracite. In the case of this salt we have additional examples of the
endless variety of symbols now inflicted upon the chemist. In the

Ann. de Chimie et de Phys. it is represented by Mg B* + 16 H,
while in the Journal de Chimie Medicate we have (2 (Mgo)-f Tfor>
+ 16 H2 o), and yet both writers agree in considering it as similar to
boracite combined with 16 atoms of water. Both differ from Berzelius.

From the solution which yielded these crystals there afterwards
separated abundance of large brilliant, hard, transparent crystals
in the form of oblique rhombic prisms.

This salt was found to be a double borate of soda and magnesia:
when heated it swelled, and lost 525 per cent, of water of crystalliza-
tion. The calcined residue redissolved in water, but so slowly that

Intelligence and Miscellaneous Articles, 1 57

it seemed at first to be insoluble : the solution was alkaline, and
was not precipitated by ammonia. It has the characteristic pro-
perty of becoming turbid when it is heated to about 160° Fahr. and
depositing a great quantity of a white precipitate, which gradually
redissolves as the solution cools. It is owing to the formation of
this salt in the mixture of solutions of sulphate of magnesia and
borax, that a precipitate is occasioned when it is heated. This
precipitation is occasioned by the formation and precipitation of
sub-borate of magnesia, while borate of soda and boracic acid
remain in solution. On evaporating the liquor separated by filtra-
tion from the precipitate, boracic acid evaporates with the water,
and a saline mass is obtained, from which alcohol separates a
quantity of boracic acid. This sub-borate of magnesia is most
readily obtained by heating a mixture of solution of borax and sul-
phate of magnesia.

Hydrate or carbonate of magnesia dissolves in a hot solution of
boracic acid. The solution is alkaline : by evaporation it deposits
a salt in crystalline grains, which is very soluble in water, although
the solution goes on slowly. The solution is not precipitated at a
high temperature, but when mixed with a solution of borax, it
deposits a white precipitate if heated to about 160°. The preci-
pitate disappears at common temperatures.

This borate of magnesia when heated to redness loses much
water and boracic acid. The residue has the appearance of pumice-
stone : water dissolves much pure boracic acid from it, and pure
magnesia remains. It appears, then, that at high temperatures the
affinity between magnesia and boracic acid is entirely destroyed. —
Ann. de Chim. et de Phys.> torn. liii. p. 433.

ACTION OF TANNIN AND SOME OTHER SUBSTANCES ON THE
ROOTS OF PLANTS. BY M. PAYEN.

It has been repeatedly stated by M. Silvestre, Jun., that trees
soon died when their roots came into contact with the remains of
the roots of oak trees cut down near them. This was supposed by
some to be owing to the action of tannin, while others maintained
that it was innocuous. M. Payen instituted direct experiments on
this subject. In order to observe the influence of tannin and to
appreciate its effects comparatively with those of other agents,
M. Payen placed grains of wheat, rye, barley, oats, and maize, in
contact with equal quantities of the following liquids, and all other
circumstances were equal: 1st, aerated distilled water; 2nd, the
same containing 0-01 of its weight of a saturated solution of car-
bonate of soda; 3rd, the same containing only 0 001 of its weight
of the same saturated solution of carbonate of soda; 4th, a solution
containing 0*001 of pure tannin ; 5th, a solution containing 0*001
of sulphuric acid ; 6th, distilled water saturated with lime.

In the distilled water, in the liquid containing 0*001 of solution
of carbonate of soda, and in the solution of tannin, germination took
place in the order stated ; in the three other liquids, those contain-
ing 0001 of acid, 0*001 of carbonate of soda, and saturated with
lime, germination did not occur.

158 Intelligence and Miscellaneous Articles.

The distilled water soon became slightly acid. The development
of the stalks, at first rather more rapid than in the solution of 0001
of carbonate of soda, slackened comparatively with that which oc-
curred in the last liquor : when this was neutralized by the acid
excreted by vegetation, the original quantity of alkali was added.
In bitter liquids, the white roots and green stalks were several
centimetres long in a fortnight.

In the solution of 0*001 of tannin, all the radicles gradually ac-
quired a brown tint, and were but slightly and imperfectly deve-
loped. The plumulae continued whitish, but did not develop any
green stalks j there was therefore a strongly marked obstacle to
any further development in this liquid.

M. Payen concludes from the preceding and other experiments,
that,

1st, Tannin, even in small quantity, acts deleteriously on the
roots of certain plants :

2ndly, Acids in small proportion are hurtful to germination:

3rdly, Alkalies in small quantity are favourable to the progress
of vegetation :

4thly, The saturation of the acidity developed during germina-
tion hastens its progress and favours the ulterior development.

These experiments account for one of the useful effects of lime,
of vegetable ashes and calcareous marl, and for the unfavour-
able influence of alkalies used in too great quantity, or unequally
distributed. — Journal de Chimie Medicate, Avril 1834?.

DISCOVERY OF PLATINA IN FRANCE.

M. Villain has informed the Academy of Sciences of the discovery
of a great mine of argentiferous galena : it is the mine of Melle, or
Mello, situated in the departement de Deux Sevres. The mine
contains two varieties of the ore, one with large facets, and the
other very brilliant steel-grained ore. The former contains from
40 to 66 per cent, of lead : in cupelling the silver M. Villain
obtained a blackish residue, which he suspected to be platina
and iridium. Some of the samples of galena contained .^.g-Vtnr of
its weight of platina, or 100 pounds of the lead should contain
1 ounce 7 gros and 46 grains of platina, and it is calculated that
the daily product of platina will amount to 1 pound 4 ounces 2 gros
and 28 grains. The steel-grained variety contains most platina. —
Journal de Chimie Medicate, Feb. 1834.

PROFESSOR HAUSMANN ON MR. WHEWELl/s ACCOUNT OF
HIS MINEUALOGICAL WORKS.

We are requested by Professor Hausmann to insert the following
remarks.

" Gottingen, July 5, 1834.

11 The Report on the recent progress and present state of Mine-
ralogy, by Mr. W. Whewell, contains the erroneous statement of
my being a pupil of Mohs, and that I worked in the spirit and after
the method of that master. To correct this error respecting my
writings, and with regard to German mineralogical literature, I
wish to state that I do not even personally know Mohs, though I

Intelligence and Miscellaneous Articles, J 59

'O

esteem him much. I studied at Brunswick under Knoch, and here
at Gottingen under Blumenbach. Already in 1803, and therefore
earlier than Mohs, I became a mineralogical writer, building my
system on peculiar views belonging to no other school. I was the
first who appeared as opponent to Werner; assisted in the spreading
of Hauy's theory ; and published my first mineralogical system
in 1809^ founded on chemical composition and external characters.
I gave in 1813 a complete Handbuch on Mineralogy. Later I
treated Crystallography on a method of my own, totally different
from that of Mohs, though he was publishing at the same time; and
in 1821 I completed my method in a quarto volume of 677 pages,
entitled, 'Examinations on the Forms of Lifeless Nature;' and next,
in the first volume of my new edition of Mineralogy, in 1828, which
work I had the honour to present to the London Geological Society.
Had Mr. W. looked into this book, he might have convinced him-
self of his erroneous assertion; and as it is not indifferent to me
how England judges of me, I should be greatly obliged if through
your Journal his statement could be rectified. Hausmann."

IMPROVEMENT IN PROFESSOR HENSLOW's CLINOMETER. BY
J. H. PRATT, ESQ.

To the Editors of the Philosophical Magazine and Journal.

Gentlemen,
I have lately had occasion to purchase one of the Clinometers
sold by Messrs. Watkins and Hill, Charing Cross, and invented,
I believe, by Professor Henslow ; but being struck with the want
of accuracy, or rather the liability of error, in the determination of
the dip of a stratum by its means, 1 have been induced to make a
slight alteration in the construction. My own I have had altered,
and find it answers very well, and the object of my troubling you
with this communication is to suggest the same to any person that
may have experienced the same inconvenience with myself. The
only alteration is to have the spirit-level on the outside of the lid
of the box, instead of the inside of the bottom of the box. With
this construction it is necessary merely to place the box flat on the
bed of the stratum and elevate the lid till the spirit-level shows that
the lid is horizontal : the brazen arc will then show the dip.

1 remain, yours, &c.
Finsbury Circus, June 12, 1834. J. H. Pratt.

P.S. The spirit-level is so imbedded in the wood that there is no
fear of its being broken.

PRIMARY GEOLOGY.

We are informed that Dr. Boase's Treatise on Primary Geology,
just published, contains, in addition to copious practical details
concerning the primary rocks, a full exposition of his objections to
the prevailing Plutonic Theory. This subject, it may be remem-
bered, was appointed by the British Association for the Advance-
ment of Science, at Cambridge, to be discussed at their next meeting
at Edinburgh.

1

a

■

London. — June 1, 2. Very hot and dry. 3. Slight
rain. 4. Cloudy : rain. 5. Cloudy : fine.
6 — 9. Very fine. 10. Dark clouds. 11. Rain.
12. Heavy rain. 13. Overcast and windy.
14— 16. Very fine. 17. Showery. 18. Cloudy
and cool. 19. Fine. 20. Very hot. 21. Ex-
cessively hot and dry: thermometer 91° in shade:
lightning and heavy rain at night. 22. Cloudy.
23, 24. Hot and dry. 25. Hazy. 26, 27. Fine,
with clouds. 28. Fine. 29. Dry haze. 30 Fine.
— A moderate quantity of rain" has fallen in this
month, but still below the average, and not in pro-
portion to the high temperature, nor, consequently,
equal to the demands of many kinds of vegetation.
The latter, however, would have suffered much
more had not the supply, limited as it was, been at
such intervals throughout the month as to leave
them exposed to no protracted period of drought.

Boston.-— June 1. Fine. 2. Fine: thermometer
3 p.m. 83°. 3. Fine. 4. Fine : rain p.m.
5. Rain : rain early a.m. 6. Cloudy. 7 — 9. Fine.
10. Cloudy. 11, 12. Fine: rain p.m. 13. Fines
14. Fine: rain early a.m.: rain with thunder and
lightning p.m. 15. Fine. 16. Cloudy: stormy
with rain p.m. 17. Stormy. 18. Fine: rain p.m.
19, 20. Cloudy. 21. Fine: thermometer at noon
865;2 p.m, 87:*5; half-past 3, 81-5: rain p.m.
22. Cloudy. 23, 24. Fine. 25, 26. Cloudy.
27. Cloudy : rain early a.m. 28. Fine. 29. Cloudy.
30. Fine.

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THE

LONDON and EDINBURGH
PHILOSOPHICAL MAGAZINE

AND

JOURNAL OF SCIENCE.

[THIRD SERIES.]

SEPTEMBER 1834.

XXV. Experimental Researches in Electricity. — Seventh Series.
By Michael Faraday, D.C.L. F.R.S. Fuller ian Prof.
Chem. Royal Institution, Corr. Memb. Royal andlmp.Acadd.
of Sciences, Paris, Petersburgh, Florence, Copenhagen, Berlin,
Src*

§. 11. On Electro-chemical Decomposition, continued.
% iv. On some general conditions of Electro-decom-
position. % v. On a new Measurer of Volta-electri-
city. <[[ vi. On the primitive or secondary character
of bodies evolved hi Electro-decomposition, f vii. On
the defnite nature and extent of Electro-chemical De-
compositions. §. 18. On the absolute quantity of
Electricity associated with the particles or atoms of
Matter.

Preliminary.
661. fT,HE theory which I believe to be a true expression
-■- of the facts of electro-chemical decomposition, and
which I have therefore detailed in a former series of these
Researches f, is so much at variance with those previously ad-
vanced, that I find the greatest difficulty in stating results, as
I think, correctly, whilst limited to the use of terms which
are current with a certain accepted meaning. Of this kind is
the term pole, with its prefixes of positive and negative, and
the attached ideas of attraction and repulsion. The general
phraseology is that the positive pole attracts oxygen, acids,

* From the Philosophical Transactions for 1834, Part I. p. 77- This
paper was received by the Royal Society January 9th, and read January
23rd, February Gth and 13th, 1834.

t A notice of the Researches here referred to has been given in the Lond.
and Edinb. Phil. Mag. vol. hi. p. 460. — Edit.

Third Series. Vol. 5. No. 27. Sept. 1 834/. Y

162 Dr. Faraday's Experimental Researches in Electricity,

&c, or more cautiously, that it determines their evolution
upon the surface ; and that the negative pole acts in an equal
manner upon hydrogen, combustibles, metals, and bases.
According to my view, the determining force is not at the
poles, but within the decomposing body ; and the oxygen and
acids are rendered at the negative extremity of that body,
whilst hydrogen, metals, &c, are evolved at the positive ex-
tremity (518. 524.*).

662. To avoid, therefore, confusion and circumlocution, and
for the sake of greater precision of expression than I can other-
wise obtain, I have deliberately considered the subject with two
friends, and with their assistance and concurrence in framing
them, I purpose henceforward using certain other terms,
which I will now define. The poles, as they are usually called,
are only the doors or ways by which the electric current
passes into and out of the decomposing body (556.); and they
of course, when in contact with that body, are the limits of its
extent in the direction of the current. The term has been
generally applied to the metal surfaces in contact with the
decomposing substance ; but whether philosophers generally
would also apply it to the surfaces of air (465. 471.) and
water (493.), against which I have effected electro-chemical
decomposition, is subject to doubt. In place of the term pole,
I propose using that of Electrodef, and I mean thereby that
substance, or rather surface, whether of air, water, metal, or
any other body, which bounds the extent of the decomposing
matter in the direction of the electric current.

663. The surfaces at which, according to the common
phraseology, the electric current enters and leaves a decom-
posing body, are most important places of action, and require
to be distinguished apart from the poles, with which they are
mostly, and the electrodes, with which they are always, in
contact. Wishing for a natural standard of electric direction
to which I might refer these, expressive of their difference
and at the same time free from all theory, I have thought it
might be found in the earth. If the magnetism of the earth
be due to electric currents passing round it, the latter must
be in a constant direction, which, according to present usage of
speech, would be from east to west, or, which will strengthen
this help to the memory, that in which the sun appears to
move. If in any case of electro-decomposition we consider
the decomposing body as placed so that the current passing
through it shall be in the same direction, and parallel to that
supposed to exist in the earth, then the surfaces at which the

* These numbers, and others referred to in these Researches from 450.
to 563., both inclusive, belong to the Fifth Series, noticed in our third
volume, as already stated. — Edit.

"|" f)MxTf>out and 6^o( a way.

' Definitions of netn Terms. 163

electricity is passing into and out of the substance would
have an invariable reference, and exhibit constantly the same
relations of powers. Upon this notion we purpose calling
that towards the east the anode*, and that towards the west
the cathode f ; and whatever changes may take place in our
views of the nature of electricity and electrical action, as they
must affect the natural standard referred to in the same direc-
tion, and to an equal amount with any decomposing substances
to which these terms may at any time be applied, there seems
no reason to expect that they will lead to confusion, or tend
in any way to support false views. The anode is therefore
that surface at which the electric current, according to our
present expression, enters: it is the negative extremity of the
decomposing body; is where oxygen, chlorine, acids, &c., are
evolved ; and is against or opposite the positive electrode.
The cathode is that surface at which the current leaves the
decomposing body, and is its positive extremity ; the com-
bustible bodies, metals, alkalies, and bases, are evolved there,
and it is in contact with the negative electrode.

664. I shall have occasion in these Researches, also, to class
bodies together according to certain relations derived from
their electrical actions (822.); and wishing to express those
relations without at the same time involving the expression of
any hypothetical views, I intend using the following names
and terms. Many bodies are decomposed directly by the
electric current, their elements being set free ; these I propose
to call electrolytes %. Water, therefore, is an electrolyte. The
bodies which, like nitric or sulphuric acids, are decomposed
in a secondary manner (752. 757.), are not included under
this term. Then for electro-chemically decomposed, I shall
often use the term elecirolyzed, derived in the same way, and
implying that the body spoken of is separated into its com-
ponents under the influence of electricity : it is analogous in
its sense and sound to analyze, which is derived in a similar
manner. The term electrolytical will be understood at once.
Muriatic acid is electrolytical, boracic acid is not.

665, Finally, I require a term to express those bodies which
can pass to the electrodes, or, as they are usually called, the
poles. Substances are frequently spoken of as being electro-
negative, or electro-positive, according as they go under the
supposed influence of a direct attraction to the positive or
negative pole. But these terms are much too significant for
the use to which I should have to put them ; for though the

* xvoc. upwards, olos a way\ the way which the sun rises.
t Kotrex. downwards, olos a way ; the way which the sun sets.
X faiHTftov, and Ava solvo. N. Electrolyte, V. Electrolyze.
Y2

164- Dr. Faraday's Experimental Researches in Electricity.

meanings are perhaps right, they are only hypothetical, and
may be wrong ; and then, through a very imperceptible, but
still very dangerous, because continual, influence, they do
great injury to science, by contracting and limiting the ha-
bitual views of those engaged in pursuing it. I propose to
distinguish these bodies by calling those anions* which go to
the anode of the decomposing body; and those passing to the
cathode, cations-f; and when I have occasion to speak of these
together, I shall call them ions. Thus, the chloride of lead
is an electrolyte, and when electrolyzed evolves the two ions,
chlorine and lead, the former being an anion, and the latter
a cation.

666. These terms being once well defined, will, I hope, in
their use enable me to avoid much periphrasis and ambiguity
of expression. I do not mean to press them into service more
frequently than will be required, for I am fully aware that
names are one thing and science another J.

667. It will be well understood that I am giving no opinion
respecting the nature of the electric current now, beyond
what I have done on a former occasion (283. § 517.) ; and that
though I speak of the current as proceeding from the parts
which are positive to those which are negative (663.), it is
merely in accordance with the conventional, though in some
degree tacit, agreement entered into by scientific men, that
they may have a constant, certain, and definite means of re-
ferring to the direction of the forces of that current.

f iv. On some general Conditions of Electro-chemical De-
composition.

669. From the period when electro-chemical decomposition
was first effected to the present time, it has been a remark,
that those elements which, in the ordinary phenomena of
chemical affinity, were the most directly opposed to each other,
and combined with the greatest attractive force, were those
which were the most readily evolved at the opposite extre-
mities of the decomposing bodies (549.).

670. If this result was evident when water was supposed to
be essential to, and was present, in almost every case of such
decomposition (472.), it is far more evident now that it has
been shown and proved that water is not necessarily con-

♦ uvtov that which goes up. (Neuter participle.)

+ KocTtov that which goes down.

\ Since this paper was read, I have changed some of the terms which
were first proposed, that I might employ only such as were at the same
time simple in their nature, clear in their reference, and free from hy-
pothesis.

§ See Lond. and Edinb. Phil. Mag. vol. iii. p. 1GG. — Edit.

Conditions of the Constitution of Electrolytes. 165

cerned in the phenomena (474?.), and that other bodies much
surpass it in some of the effects supposed to be peculiar to
that substance.

671. Water, from its constitution and the nature of its ele-
ments, and from its frequent presence in cases of electrolytic
action, has hitherto stood foremost in this respect. Though
a compound formed by very powerful affinity, it yields up its
elements under the influence of a very feeble electric current ;
and it is doubtful whether a case of electrolyzation can occur,
where, being present, it is not resolved into its first princi-
ples.

672. The various oxides, chlorides, iodides, and salts (402.),
which I have shown are decomposable by the electric current
when in the liquid state, under the same general law with
water, illustrate in an equally striking manner the activity, in
such decompositions, of elements directly and powerfully op-
posed to each other by their chemical relations.

673. On the other hand, bodies dependent on weak affi-
nities very rarely give way. Take, for instance, glasses : many
of those formed of silica, lime, alkali, and oxide of lead, may
be considered as little more than solutions of substances one
in another*. If bottle-glass be fused, and subjected to the
voltaic pile, it does not appear to be at all decomposed (408.).
If flint-glass, which contains substances more directly op-
posed, be operated upon, it suffers some decomposition ; and if
borate of lead glass, which is a definite chemical compound, be
experimented with, it readily yields up its elements (408.#).

674. But the result which is found to be so striking in the
instances quoted is not at all borne out by reference to other
cases where a similar consequence might have been expected.
It may be said, that my own theory of electro-chemical de-
composition would lead to the expectation that all compound
bodies should give way under the influence of the electric
current with a facility proportionate to the strength of the
affinity by which their elements, either proximate or ultimate,
are combined. I am not sure that that follows as a conse-
quence of the theory ; but if the objection be supposed one pre-
sented by facts, I have no doubt it will be removed when we
obtain a more intimate acquaintance with, and precise idea o£
the nature of chemical affinity and the mode of action of an
electric current over it (518. 524.)): besides which, it is just
as directly opposed to any other theory of electro-chemical

* Philosophical Transactions, 1830, p. 49.

f These numbers, and the others referred to from 380. to 449., both in-
clusive, belong to the Fourth Series of these Researches, noticed in Lond.
and Edinb. Phil. Mag. vol. iii. p. 449. — Edit.

166 Dr. Faraday's Experimental Researches in Electricity.

decomposition as the one I have propounded ; for if it be ad-
mitted, as is generally the case, that the more directly bodies
are opposed to each other in their attractive forces, the more
powerfully do they combine, then the objection applies with
equal force to any of the theories of electrolyzation which
have been considered, and is an addition to those which
I have taken against them.

675. Amongst powerful compounds which are not decom-
posed, boracic acid stands prominent (408.). Then again,
the iodide of sulphur, and the chlorides of sulphur, phos-
phorus, and carbon, are not decomposable under common
circumstances, though their elements are of a nature which
would lead to a contrary expectation. Chloride of antimony
(402. 690.), the hydro-carbons, acetic acid, ammonia, and
many other bodies undecomposable by the voltaic pile, would
seem to be formed by an affinity sufficiently strong to indicate
that the elements were so far contrasted in their nature as to
sanction the expectation that the pile would separate them,
especially as in some cases of mere solution (530. 544.), where
the affinity must by comparison be very weak, separation
takes place*.

676. It must not be forgotten, however, that much of this
difficulty, and perhaps the whole, may depend upon the ab-
sence of conducting power, which, preventing the transmis-
sion of the current, prevents of course the effects due to it.
All known compounds being non-conductors when solid, but
conductors when liquid, are decomposed, with perhaps the
single exception at present known of periodide of mercury
(679. 691.) ; and even water itself, which so easily yields up
its elements when the current passes, if rendered quite pure,
scarcely suffers change, because it then becomes a very bad
conductor.

677. If it should hereafter be proved that the want of de-
composition in those cases where, from chemical considera-
tions, it might be so strongly expected (669. 674. 672.), is
due to the absence or deficiency of conducting power, it would
also be proved, at the same time, that decomposition depends
upon conduction, and not the latter upon the former (413.);
and in water this seems to be very nearly decided. On the
other hand, the conclusion is almost irresistible, that in elec-
trolytes the power of transmitting the electricity across the
substance is dependent upon their capability of suffering de-
composition ; taking place only whilst they are decomposing,

* With regard to solution, 1 have met with some reasons for supposing
that it will probably disappear as a cause of transference, and intend re-
suming the consideration at a convenient opportunity.

Conditions of the Constitution of Electrolytes. 167

and being proportionate to the quantity of elements separated
(821.). I may not, however, stop to discuss this point ex-
perimentally at present.

678. When a compound contains such elements as are
known to pass towards the opposite extremities of the voltaic
pile, still the proportions in which they are present appear to
be intimately connected with capability in the compound of
suffering or resisting decomposition. Thus, the protochloride
of tin readily conducts, and is decomposed (402.), but the
perchloride neither conducts nor is decomposed (406.). The
protiodide of tin is decomposed when fluid (402.); the per-
iodide is not (405.). The periodide of mercury when fused
is not decomposed (691.), even though it does conduct. I was
unable to contrast it with the protiodide, the latter being con-
verted into mercury and periodide by heat.

679. These important differences induced me to look more
closely to certain binary compounds, with a view of ascertain-
ing whether a law regulating the decomposability according to
some relation of the proportionals or equivalents of the ele-
ments, could be discovered. The proto compounds only,
amongst those just referred to, were decomposable ; and on
referring to the substances quoted to illustrate the force and
generality of the law of conduction and decomposition which
I discovered (402.), it will be found that all the oxides, chlo-
rides, and iodides subject to it, except the chloride of anti-
mony and the periodide of mercury, (to which may now per-
haps be added corrosive sublimate,) are also decomposable,
whilst many per compounds of the same elements, not subject
to the law, were not so (405. 406.).

680. The substances which appeared to form the strongest
exceptions to this general result were such bodies as the sul-
phuric, phosphoric, nitric, arsenic, and other acids.

681. On experimenting with sulphuric acid, I found no
reason to believe that it was by itself a conductor of, or de-
composable by, electricity, although I had previously been
of that opinion (552.). When very strong it is a much worse
conductor than if diluted*. If then subjected to the action
of a powerful battery, oxygen appears at the anode, or posi-
tive electrode, although much is absorbed (728.), and hydro-

fen and sulphur appear at the cathode, or negative electrode.
Jow the hydrogen has with me always been pure, not sul-
phuretted, and has been deficient in proportion to the sulphur
present, so that it is evident that when decomposition oc-
curred water must have been decomposed. I endeavoured to
make the experiment with anhydrous sulphuric acid. It ap-

* De la Rive.

168 Dr. Faraday's Experimental Researches in Electricity.

peared to me that in that state, when fused, sulphuric acid
was not a conductor, nor decomposed ; but I had not enough
of the dry acid in my possession to allow me to decide the
point satisfactorily. My belief is, that when sulphur appears
by the action of the pile on sulphuric acid, it is the result of
a secondary action, and that the acid itself is not electroly-
zable (757.).

682. Phosphoric acid is, I believe, also in the same condi-
tion ; but I have found it impossible to decide the point, be-
cause of the difficulty of operating on fused anhydrous phos-
phoric acid. Phosphoric acid which has once obtained water
cannot be deprived of it by heat alone. When heated, the
hydrated acid volatilizes. Upon subjecting phosphoric acid,
fused upon the ring end of a wire (401.), to the action of the
voltaic apparatus, it conducted, and was decomposed ; but
gas, which I believe to be hydrogen, was always evolved at
the negative electrode, and the wire was not affected as would
have happened had phosphorus been separated. Gas was also
evolved at the positive electrode. From all the facts, I conclude
it was the water and not the acid which was decomposed.

683. Arsenic Acid. — This substance conducted, and was
decomposed ; but it contained water, and I was unable at the
time to press the investigation so as to ascertain whether a
fusible anhydrous arsenic acid could be obtained. It forms,
therefore, at present no exception to the general result.

684. Nitrous acidj obtained by distilling nitrate of lead,
and keeping it in contact with strong sulphuric acid, was found
to conduct and decompose slowly. But on examination there
were strong reasons for believing that water was present, and
that the decomposition and conduction depended upon it. I
endeavoured to prepare a perfectly anhydrous portion, but
could not spare the time required to procure an unexception-
able result.

685. Nitric acid is a substance which I believe is not de-
composed directly by the electric current. As I want the
facts in illustration of the distinction existing between primary
and secondary decomposition, I will merely refer to them in
this place (752.).

686. That these mineral acids should confer facility of con-
duction and decomposition on water, is no proof that they are
competent to favour and suffer these actions in themselves.
Boracic acid does the same thing, though not decomposable.
M. De la Rive has pointed out that chlorine has this power
also ; but being to us an elementary substance, it cannot be
due to its capability of suffering decomposition.

687. Chloride of sulphur does not conduct, nor is it decom-

Influence of Proportions in Electrolytes. 169

posed. It consists of single proportionals of its elements, but
is not on that account an exception to the rule (679.), which
does not affirm that all compounds of single proportionals of
elements are decomposable, but that such as are decompos-
able are so constituted.

688. Protochloride of phosphorus does not conduct nor be-
come decomposed.

689. Protochloride of carbon does not conduct nor suffer
decomposition. In association with this substance, I sub-
mitted the hydro-chloride of carbon from defiant gas and
chlorine to the action of the electric current; but it also re-
fused to conduct or yield up its elements.

690. With regard to the exceptions (679.), upon closer
examination, some of them disappear. Chloride of antimony
(a compound of one proportional of antimony and one and a
half of chlorine) of recent preparation was put into a tube
(Plate I. fig. 13.) (789.), and submitted when fused to the action
of the current, the positive electrode being of plumbago. No
electricity passed, and no appearance of decomposition was
visible at first ; but when the positive and negative electrodes
were brought very near each other in the chloride, then a
feeble action occurred and a feeble current passed. The
effect altogether was so small (although quite amenable to the
law before given), and so unlike the decomposition and con-
duction occurring in all the other cases, that I attribute it to
the presence of a minute quantity of water, (for which this
and many other chlorides have strong attractions, producing
hydrated chlorides,) or perhaps of a true protochloride con-
sisting of single proportionals (695. 796.).

691. Periodide of mercury being examined in the same
manner, was found most distinctly to insulate whilst solid,
but conduct when fluid, according to the law of liquido-con-
duction (4*02.); but there was no appearance of decomposition.
No iodine appeared at the anode, nor mercury or other sub-
stance at the cathode. The case is, therefore, no exception
to the rule, that only compounds of single proportionals are
decomposable ; but it is an exception, and I think the only
one, to the statement, that all bodies subject to the law of
liquido-conduction are decomposable. I incline, however,
to believe, that a portion of protiodide of mercury is retained
dissolved in the periodide, and that to its slow decomposi-
tion the feeble conducting power is due. Periodide would be
formed, as a secondary result, at the anode; and the mercury
at the cathode would also form, as a secondary result, prot-
iodide. Both these bodies would mingle with the fluid mass,
and thus no final separation appear, notwithstanding the con-
tinued decomposition.

Third Series. Vol. 5. No. 27. Sept. 18S4. Z

170 Dr. Faraday's Experimental Researches in Electricity.

692. When perchloride of mercury was subjected to the
voltaic current, it did not conduct in the solid state, but it did
conduct when fluid. I think, also, that in the latter case it
was decomposed ; but there are many interfering circumstances
which require examination before a positive conclusion can
be drawn.

693. When the ordinary protoxide of antimony is subjected
to the voltaic current in a fused state, it also is decomposed,
although the effect from other causes soon ceases (402. 801.).
This oxide consists of one proportional of antimony and one
and a half of oxygen, and is therefore an exception to the ge-
neral law assumed. But in working with this oxide and the
chloride, I observed facts which lead me to doubt whether the
compounds usually called the protoxide and the protochloride
do not often contain other compounds, consisting of single
proportions, which are the true proto compounds, and which,
in the case of the oxide, might give rise to the decomposition
above described.

694. The ordinary sulphuret of antimony is considered as
being the compound with the smallest quantity of sulphur,
and analogous in its proportions to the ordinary protoxide.
But I find that if it be fused with metallic antimony, a new
sulphuret is formed, containing much more of the metal than
the former, and separating distinctly, when fused, both from
the pure metal on the one hand, and the ordinary gray sul-
phuret on the other. In some rough experiments, the metal
thus taken up by the ordinary sulphuret of antimony was
equal to half the proportion of that previously in the sul-
phuret, in which case the new sulphuret would consist of
single proportionals.

695. When this new sulphuret was dissolved in muriatic
acid, although a little antimony separated, yet it appeared to
me that a true protochloride, consisting of single propor-
tionals, was formed, and from that, by alkalies, &c, a true
protoxide, consisting also of single proportionals was obtain-
able. But 1 could not stop to ascertain this matter strictly
by analysis.

696. I believe, however, that there is such an oxide; that
it is often present in variable proportions in what is commonly
called protoxide, throwing uncertainty upon the results of its
analysis, and causing the electrolytic decomposition above de-
scribed.

697. Upon the whole, it appears probable that all those
binary compounds of elementary bodies which are capable of
being electrolyzed when fluid, but not whilst solid, according
to the law of liquido-conduction (394.), consist of single pro-
portionals of their elementary principles ; and it may be be-

Influence of Pro-portions in Electrolytes. 171

cause of their departure from this simplicity of composition,
that boracic acid, ammonia, perchlorides, periodides, and many
other direct compounds of elements, are indecomposable.

698. With regard to salts and combinations of compound
bodies, the same simple relation does not appear to hold good.
I could not decide this by bisulphates of the alkalies, for as
long as the second proportion of acid remained, water was
retained with it. The fused salt, therefore, conducted, and
was decomposed; but hydrogen always appeared at the ne-
gative electrode.

699. A biphosphate of soda was prepared by heating, and
ultimately fusing, the ammonia-phosphate of soda. In this
case the fused bisalt conducted, and was decomposed ; but a
little gas appeared at the negative electrode, and though I be-
lieve the salt itself was electrolyzed, I am not quite satisfied
that water was entirely absent.

700. Then a biborate of soda was prepared ; and this, I
think, is an unobjectionable case. The salt, when fused, con-
ducted, and was decomposed, and gas appeared at both elec-
trodes : even when the boracic acid was increased to three
proportionals the same effect took place.

701. Hence this class of compound combinations does not
seem to be subject to the same simple law as the former class
of binary combinations. Whether we may find reason to
consider them as mere solutions of the compound of single
proportionals in the excess of acid, is a matter which, with
some apparent exceptions occurring amongst the sulphurets,
must be left for decision by future examination.

702. In any investigation of these points, great care must
be taken to exclude water ; for if present, secondary effects
are so frequently produced as often seemingly to indicate an
electro-decomposition of substances, when no true result of
the kind has occurred (742. &c).

703. It is evident that all the cases in which decomposition
does not occur may depend upon the want of conduction (677.
413.); but that does not at all lessen the interest excited by
seeing the great difference of effect due to a change, not in the
nature of the elements, but merely in their proportions, espe-
cially in any attempt which may be made to elucidate and ex-
pound the beautiful theory put forth by Sir Humphry Davy*,
and illustrated by Berzelius and other eminent philosophers,
that ordinary chemical affinity is a mere result of the electri-
cal attractions of the particles of matter.

* Philosophical Transactions, 1807, pp. 32, 39; also 1826, pp, 387, 389.
[or Phil. Mag. first series, vol. xxviii. pp. 114, 220; also Phil. Mag. and
Annals, N.S., vol. i. p. 31-199.— Edit.]

Z 2

172 Dr. Faraday's Experimental Researches in Electricity,

f v. On a new Measurer of Volta-clcctricity.

704'. I have already said, when engaged in reducing com-
mon and voltaic electricity to one standard of measurement
(377*.)? and again when introducing my theory of electro-che-
mical decomposition (504?. 505. 510.), that the chemical de-
composing action of a current is constant for a constant quan-
tity of electricity, notwithstanding the greatest variations in its
sources, in its intensity, in the size of the electrodes used, in
the nature of the conductors (or non-conductors (307. f))
through which it is passed, or in other circumstances. The
conclusive proofs of the truth of these statements shall be
given almost immediately (733. &c).

705. I endeavoured upon this law to construct an instru-
ment which should measure out the electricity passing through
it, and which, being interposed in the course of the current
used in any particular experiment, should serve at pleasure,
either as a comparative standard of effect, or as a positive
measurer of this subtile agent.

706. There is no substance better fitted, under ordinary
circumstances, to be the indicating body in such an instru-
ment than water ; for it is decomposed with facility when ren-
dered a better conductor by the addition of acids or salts; its
elements may in numerous cases be obtained and collected
without any embarrassment from secondary action, and, being
gaseous, they are in the best physical condition for separation
and measurement. Water, therefore, acidulated by sulphuric
acid, is the substance I shall generally refer to, although it
may become expedient in peculiar cases or forms of experi-
ment to use other bodies (843.).

707. The first precaution needful in the construction of the
instrument was to avoid the recombination of the evolved
gases, an effect which the positive electrode has been found
so capable of producing (571. J). For this purpose various
forms of decomposing apparatus were used. The first con-
sisted of straight tubes, each containing a plate and wire of
platina soldered together by gold, and fixed hermetically in
the glass at the closed extremity of the tube (Plate I. fig. 5.)
The tubes were about eight inches long, 0*7 of an inch in dia-
meter, and graduated. The platina plates were about an inch
long, as wide as the tubes would permit, and adjusted as near

* See Lond. and Edinb. Phil. Mag., vol. iii. p. 362.— Edit.

f Ibid. p. 171.

X This and every other number referred to in these Researches, from 564.
to 660., belong to the Sixth Series, noticed in Lond. and Edinb. Phil, Mag.,
vol. iv. p. 291. — Edit*

Various Forms of the Volta-electromcter. 173

to the mouths of the tubes as was consistent with the safe col-
lection of the gases evolved. In certain cases, where it was
required to evolve the elements upon as small a surface as
possible, the metallic extremity, instead of being a plate, con-
sisted of the wire bent into the form of a ring (fig. 6.).
When these tubes were used as measurers, they were filled
with the dilute sulphuric acid, and inverted in a basin of the
same liquid (fig. 7.), being placed in an inclined position, with
their mouths near to each other, that as little decomposing
matter should intervene as possible; and also, in such a direc-
tion that the platina plates should be in vertical planes (720.).

708. Another form of apparatus was that delineated (fig. 8.).
The tube is bent in the middle ; one end is closed ; in that
end is fixed a wire and plate, a, proceeding so far downwards,
that, when in the position figured, it shall be as near to the
angle as possible, consistently with the collection, at the closed
extremity of the tube, of all the gas evolved against it. The
plane of this plate is also perpendicular (720.). The other
metallic termination, b, is introduced at the time decomposi-
tion is to be effected, being brought as near the angle as pos-
sible, without causing any gas to pass from it towards the
closed end of the instrument. The gas evolved against it is
allowed to escape.

709. The third form of apparatus contains both electrodes
in the same tube; the transmission, therefore, of the electri-
city, and the consequent decomposition, is far more rapid than
in the separate tubes. The resulting gas is the sum of the
portions evolved at the two electrodes, and the instrument is
better adapted than either of the former as a measurer of the
quantity of voltaic electricity transmitted in ordinary cases.
It consists of a straight tube (fig. 9.) closed at the upper ex-
tremity, and graduated, through the sides of which pass the
platina wires (being fused into the glass), which are connected
with two plates within. The tube is fitted by grinding into
one mouth of a double-necked bottle. If the latter be one
half or two thirds full of the dilute sulphuric acid, it will, upon
inclination of the whole, flow into the tube and fill it. When
an electric current is passed through the instrument, the gases
evolved against the plates collect in the upper portion of the
tube, and are not subject to the recombining power of the
platina.

710. Another form of the instrument is given at fig. 10.

711. A fifth form is delineated (fig. 11.). This I have
found exceedingly useful in experiments continued in succes-
sion for days together, and where large quantities of indicat-
ing gas were to be collected. It is fixed on a weighted foot,

174 Dr. Faraday's Experimental Researches in Electricity.

and has the form of a small retort containing the two elec-
trodes: the neck is narrow, and sufficiently long to deliver gas
issuing from it into a jar placed in a small pneumatic trough.
The electrode chamber, sealed hermetically at the part held
in the stand, is five inches in length, and 0*6 of an inch in
diameter; the neck about nine inches in length, and 0*4 of an
inch in diameter internally. The figure will fully indicate the
construction.

712. It can hardly be requisite to remark, that in the ar-
rangement of any of these forms of apparatus, they, and the
wires connecting them with the substance, which is collaterally
subjected to the action of the same electric current, should be
so far insulated as to ensure a certainty that all the electri-
city which passes through the one shall also be transmitted
through the other.

713. Next to the precaution of collecting the gases, if min-
gled, out of contact with the platinum, was the necessity of
testing the law of a definite electrolytic action, upon water at
least, under all varieties of condition; that, with a conviction
of its certainty, might also be obtained a knowledge of those
interfering circumstances which would require to be practi-
cally guarded against.

714. The first point investigated was the influence or in-
difference of extensive variations in the size of the electrodes,
for which purpose instruments like those last described (709.
710. 711.) were used. One of these had plates 0*7 of an inch
wide, and nearly four inches long; another had plates only
0*5 of an inch wide, and 0*8 of an inch long; a third had
wires 0*02 of an inch in diameter, and three inches long; and
a fourth similar wires only half an inch in length. Yet when
these were filled with dilute sulphuric acid, and, being placed
in succession, had one common current of electricity passed
through them, very nearly the same quantity of gas was
evolved in all. The difference was sometimes in favour of
one, and sometimes on the side of another ; but the general
result was that the largest quantity of gases was evolved upon
the smallersurface of the wires.

715. Experiments of a similar kind were made with the
single-plate, straight tubes (707.) , and also with the curved
tubes (70S.), with similar consequences; and when these, with
the former tubes, were arranged together in various ways, the
result, as to the equality of action of large and small metallic
surfaces when delivering and receiving the same current of
electricity, was constantly the same. As an illustration, the
following numbers are given. An instrument with two wires
evolved 74*3 volumes of mixed gases ; another with plates

Definite Electrolytic Action, with different-shed Electrodes. 175

73*25 volumes ; whilst the sum of the oxygen and hydrogen
in two separate tubes amounted to 73*65 volumes. In an-
other experiment the volumes were 55*3, 55*3, and 54'4-.

716. But it was observed in these experiments, that in
single-plate tubes (707.) more hydrogen was evolved at the
negative electrode than was proportionate to the oxygen at
the positive electrode; and generally, also, more than was
proportionate to the oxygen and hydrogen in a double-plate
tube. Upon more minutely examining these effects, I was
led to refer them, and also the differences between wires and
plates (714-.), to the solubility of the gases evolved, especially
at the positive electrode.

717. When the positive and negative electrodes are equal
in surface, the bubbles which rise from them in dilute sul-
phuric acid are always different in character. Those from
the positive plate are exceedingly small, and separate instantly
from every part of the surface of the metal, in consequence
of its perfect cleanliness (633.) ; whilst in the liquid they give
it a hazy appearance, from their number and minuteness ; are
easily carried down by currents ; and therefore not only pre-
sent far greater surface of contact with the liquid than larger
bubbles would do, but are retained a much longer time in
mixture with it. But the bubbles at the negative surface,
though they constitute twice the volume of the gas at the po-
sitive electrode, are nevertheless very inferior in number.
They do not rise so universally from every part of the sur-
face, but seem to be evolved at different points ; and though
so much larger, they appear to cling to the metal, separating
with difficulty from it, and when separated, instantly rising to
the top of the liquid. If, therefore, oxygen and hydrogen
had equal solubility in, or powers of combining with, water
under similar circumstances, still under the present conditions
the oxygen would be far the most liable to solution ; but when
to these is added its well-known power of forming a com-
pound with water, it is no longer surprising that such a com-
pound should be produced in small quantities at the positive
electrode; and indeed the bleaching power which some philo-
sophers have observed in a solution at this electrode, when
chlorine and similar bodies have been carefully excluded, is
probably due to the formation there, in this manner, of oxy-
water.

718. That more gas was collected from the wires than from
the plates, I attribute to the circumstance, that as equal quan-
tities were evolved in equal times, the bubbles at the wires
having been more rapidly produced, in relation to any part of
the surface, must have been much larger ; have been there-

1 76 Dr. Faraday's Experimental Researches in Electricity.

fore in contact with the fluid by a much smaller surface, and
for a much shorter time than those at the plates; hence less
solution and a greater collection.

719. There was also another effect produced, especially by
the use of large electrodes, which was both a consequence
and a proof of the solution of part of the gas evolved there.
The collected gas, when examined, was found to contain small
portions of nitrogen. This I attribute to the presence of air
dissolved in the acid used for decomposition. It is a well-
known fact, that when bubbles of a gas but slightly soluble in
water or solutions pass through them, the portion of this gas
which is dissolved displaces a portion of that previously in
union with the liquid: and so, in the decompositions under
consideration, as the oxygen dissolves, it displaces a part of
the air, or at least of the nitrogen, previously united to the
acid ; and this proceeds most extensively with large plates, be-
cause the gas evolved at them is in the most favourable condi-
tion for solution.

720. With the intention of avoiding this solubility of the
gases as much as possible, I arranged the decomposing plates
in a vertical position (707. 708.), that the bubbles might
quickly escape upwards, and that the downward currents in
the fluid should not meet ascending currents of gas. This
precaution I found to assist greatly in producing constant re-
sults, and especially in experiments to be hereafter referred
to, in which other liquids than dilute sulphuric acid, as for in-
stance solution of potash, were used.

721. The irregularities in the indications of the measurer
proposed, arising from the solubility just referred to, are but
small, and may be very nearly corrected by comparing the
results of two or three experiments. They may also be al-
most entirely avoided by selecting that solution which is found
to favour them in the least degree (728.) ; and still further un-
collecting the hydrogen only, and using that as the indicating-
gas ; for being much less soluble than oxygen, being evolved
with twice the rapidity and in larger bubbles (717.), it can be
collected more perfectly and in greater purity.

722. From the foregoing and many other experiments, it
results that variation in the size of the electrodes causes no va-
riation in the chemical action of a given quantity of electricity
upon water.

723. The next point in regard to which the principle of
constant electro-chemical action was tested, was variation of
intensity. In the first place, the preceding experiments were
repeated, using batteries of an equal number of plates, strongly
and weakly charged ; but the results were alike. They were

Definite Electrolytic Action, "with different-sized Electrodes. 17?

then repeated, using batteries sometimes containing forty, and
at other times only five pairs of plates; but the results were
still the same. Variations therefore in the intensity, caused by
difference in the strength of charge, or in the number of al-
ternations used, produced no difference as to the equal action of'
large and small electrodes.

724. Still these results did not prove that variation in the
intensity of the current was not accompanied by a corre-
sponding variation in the electro-chemical effects, since the
actions at all the surfaces might have increased or diminished
together. The deficiency in the evidence is, however, com-
pletely supplied by the former experiments on different-
sized electrodes ; for with variation in the size of these, a va-
riation in the intensity must have occurred. The intensity of
an electric current traversing conductors alike in their nature,
quality* and length, is probably as the quantity of electricity
passing through a given sectional area perpendicular to the
current, divided by the time (360. note) ; and therefore when
large plates were contrasted with wires separated by an equal
length of the same decomposing conductor (71 4.), whilst one
current of electricity passed through both arrangements, that
electricity must have been in a very different state, as to ten-
sion9 between the plates and between the wires ; yet the che-
mical results were the same.

725. The difference in intensity, under the circumstances
described, may be easily shown practically, by arranging two
decomposing apparatus as in fig. 12, where the same fluid is
subjected to the decomposing power of the same current of
electricity, passing in the vessel A between large platina
plates, and in the vessel B between small wires. If a third
decomposing apparatus, such as that delineated fig. 11. (7H.)j
be connected with the wires at ab9 fig. 12, it will serve suffi-
ciently well, by the degree of decomposition occurring in it,
to indicate the relative state of the two plates as to intensity ;
and if it then be applied in the same way, as a test of the state
of the wires at a' b\ it will, by the increase of decomposition
within, show how much greater the intensity is there than at
the former points. The connexions of P and N with the vol-
taic battery are of course to be continued during the whole
time.

726. A third form of experiment in which difference of in-
tensity was obtained, for the purpose of testing the principle
of equal chemical action, was to arrange three volta-electro-
meters, so that after the electric current had passed through
one, it should divide into two parts, which, after traversing
each one of the remaining instruments, should reunite. The

Third Scries. Vol. 5. No. 27. Sept. 1834. 2 A

1 78 Dr. Faraday's Experimental Researches in Electricity.

sum of the decomposition in the two latter vessels was always
equal to the decomposition in the former vessel. But the in-
tensity of the divided current could not be the same as that it
had in its original state ; and therefore variation of intensity
has no influence on the results if the quantity of electricity
remain the same. The experiment, in fact, resolves itself
simply into an increase in the size of the electrodes (725.).

727. The third poifit, in respect to which the principle of
equal electro-chemical action on water was tested, was varia-
tion of the strength of the solution used. In order to render
the water a conductor, sulphuric acid had been added to it
(707.) ; and it did not seem unlikely that this substance, with
many others, might render the water more subject to decom-
position, the electricity remaining the same in quantity. But
such did not prove to be the case. Diluted sulphuric acid, of
different strengths, was introduced into different decomposing
apparatus, and submitted simultaneously to the action of the
same electric current (714.). Slight differences occurred, as
before, sometimes in one direction, sometimes in another; but
the final result was, that exactly the same quantity of water was
decomposed in all the solutions by the same quantity of electri-
city^ though the sulphuric acid in some was seventyfold what
it was in others. The strengths used were of specific gravity
1*495, and downwards.

% 728. When an acid having a specific gravity of about 1*336
was employed, the results were most uniform, and the oxy-
gen and hydrogen (716.) most constantly in the right propor-
tion to each other. Such an acid gave more gas than one
much weaker acted upon by the same current, apparently be-
cause it had less solvent power. If the acid were very strong,
then a remarkable disappearance of oxygen took place; thus,
one made by mixing two measures of strong oil of vitriol with
one of water, gave forty-two volumes of hydrogen, but only
twelve of oxygen. The hydrogen was very nearly the same
with that evolved from acid of the specific gravity 1*232.
I have not yet had time to examine minutely the circum-
stances attending the disappearance of the oxygen in this case,
but imagine it is due to the formation of oxywater, which
Thenard has shown is favoured by the presence of acid.

729. Although not necessary for the practical use of the
instrument I am describing, yet as connected with the im-
portant point of constant electro-chemical action upon water,
I now investigated the effects produced by an electric current
passing through aqueous solutions of acids, salts, and com-
pounds, exceedingly different from each other in their nature,
and found them to yield astonishingly uniform results. But

Definite Electrolytic Action, with different Solutions. 179

many of them which are connected with a secondary action
will be more usefully described hereafter (778.).

730. When solutions of caustic potassa or soda, or sulphate
of magnesia, or sulphate of soda, were acted upon by the elec-
tric current, just as much oxygen and hydrogen was evolved
from them as from the diluted sulphuric acid, with which they
were compared. When a solution of ammonia, rendered a
better conductor by sulphate of ammonia (554.), or a solution
of subcarbonate of potassa was experimented with, the hydro-
gen evolved was in the same quantity as that set free from the
diluted sulphuric acid with which they were compared. Hence
changes in the nature of the solution do not alter the constancy
of electrolytic action upon water.

731. I have already said, respecting large and small elec-
trodes, that change of order caused no change in the general
effect (715.). The same was the case with different solutions,
or with different intensities; and however the circumstances
of an experiment might be varied, the results came forth ex-
ceedingly consistent, and proved that the electro-chemical
action was still the same.

732. I consider the foregoing investigation as sufficient to
prove the very extraordinary and important principle with
respect to water, that when subjected to the ztifluence of the
electric current, a quantity of it is decomposed exactly propor-
tionate to the quantity of electricity which has passed, notwith-
standing the thousand variations in the conditions and circum-
stances under which it may at the time be placed ; and further,
that when the interference of certain secondary effects (742.
&c), together with the solution or recombination of the gas
and the evolution of air, are guarded against, the products of
the decomposition may be collected with such accuracy, as to
afford a very excellent and valuable measurer of the electricity
concerned in their evolution.

733. The forms of instrument which I have given, flgg.
9, 10, 11. (709. 710. 711.), are probably those which will be
found most useful, as they indicate the quantity of electricity
by the largest volume of gases, and cause the least obstruc-
tion to the passage of the current. The fluid which my pre-
sent experience leads me to prefer, is a solution of sulphuric
acid of specific gravity about 1*336, or from that to specific
gravity 1*25; but it is very essential that there should be no
organic substance, nor any vegetable acid, nor other body,
which, by being liable to the action of the oxygen or hydro-
gen evolved at the electrodes (773. &c), shall diminish their
quantity, or add other gases to them.

2 A2

180 Dr. Faraday's Experimental Researches in Electricity.

734-. In. many cases when the instrument is used as a com-
parative standard, or even as a measurer, it may be desirable
to collect the hydrogen only, as being less liable to absorption
or disappearance in other ways than the oxygen ; whilst at the
same time its volume is so large, as to render it a good and
sensible indicator. In such cases the first and second form
of apparatus have been used, figg. 7, 8. (707. 708.). The in-
dications obtained were very constant, the variations being
much smaller than in those forms of apparatus collecting both
gases; and they can also be procured when solutions are used
in comparative experiments, which, yielding no oxygen or
only secondary results of its action, can give no indications if
the educts at both electrodes be collected. Such is the case
when solutions of ammonia, muriatic acid, chlorides, iodides,
acetates, or other vegetable salts, &c, are employed.

735. In a few cases, as where solutions of metallic salts
liable to reduction at the negative electrode are acted upon,
the oxygen may be advantageously used as the measuring
substance. This is the case, for instance, with sulphate of
copper.

736. There are therefore two general forms of the instru-
ment which I submit as a measurer of electricity. One, in
which both the gases of the water decomposed are collected
(709. 710. 711.) ; and the other, in which a single gas, as the
hydrogen only, is used (707. 708.). When referred to as a
comparative instrument, (a use I shall now make of it very ex-
tensively,) it will not often require particular precaution in
the observation ; but when used as an absolute measurer, it will
be needful that the barometric pressure and the temperature
be taken into account, and that the graduation of the instru-
ments should be to one scale; the hundredths and smaller di-
visions of a cubical inch are quite fit for this purpose, and the
hundredth may be very conveniently taken as indicating a
degree of electricity.

737. It can scarcely be needful to point out further than has
been done how this instrument is to be used. It is to be in-
troduced into the course of the electric current, the action of
which is to be exerted anywhere else, and if 60° or 70° of
electricity are to be measured out, either in one or several
portions, the current, whether strong or weak, is to be con-
tinued until the gas in the tube occupies that number of divi-
sions or hundredths of a cubical inch. Or if a quantity com-
petent to produce a certain effect is to be measured, the effect
is to be obtained, and then the indication read off. In exact
experiments it is necessary to correct the volume of gas for

The Rev. P. Keith on the Internal Structure of Plants. 181

changes in temperature and pressure, and especially for mois-
ture*. For the latter object the volta-electrometer (fig. 11.)
is most accurate, as its gas can be measured over water, whilst
the others retain it over acid or saline solutions.

738. I have not hesitated to apply the term degree, in ana-
logy with the use made of it with respect to another most im-
portant imponderable agent, namely, heat; and as the de-
finite expansion of air, water, mercury, &c, is there made
use of to measure heat, so the equally definite evolution of
gases is here turned to a similar use for electricity.

739. The instrument offers the only actual measurer of
voltaic electricity which we at present possess. For without
being at all affected by variations in time or intensity, or alter-
ations in the current itself, of any kind, or from any cause, or
even of intermissions of action, it takes note with accuracy
of the quantity of electricity which has passed through it, and
reveals that quantity by inspection ; I have therefore named
it a Volta-electrometer.

740. Another mode of measuring volta-electricity may be
adopted with advantage in many cases, dependent on the
quantities of metals or other substances evolved either as pri-
mary or as secondary results ; but I refrain from enlarging
on this use of the products, until the principles on which their
constancy depends have been fully established (79 1. 843.).

741. By the aid of this instrument I have been able to
establish the definite character of electro-chemical action in
its most general sense ; and I am persuaded it will become of
the utmost use in the extensions of the science which these
views afford. I do not pretend to have made its detail per-
fect, but to have demonstrated the truth of the principle, and
the utility of the application.

[To be continued.]

XXVI. On the Internal Structure of Plants. By the Rev.
Patrick Keith, F.L.S.

[Continued from p. 121.]

Composite Organs.

The Epidermis.— HPHE epidermis of the vegetable, a term
■*■ borrowed from the anatomy of animals,
is the external envelope or integument of the plant, extending
over its whole surface, and covering the root, stem, branches,
leaves, flower, and fruit, with their appendages, the summit

* For a simple table of correction for moisture, I Dray take the liberty
of referring to my Chemical Manipulation, edition of 1830, p. 376.

182 The Rev. P. Keith on the Internal Structure of Plants.

of the pistil only excepted. But although it is extended over
the whole of the plant's surface, it is not of the same tenuity
throughout. In the root and trunk it is in many plants a
tough and leathery membrane, or it is a crust of considerable
thickness ; while in the leaves, flowers, and tender shoots, it
is a fine colourless and transparent film not thicker than a
cobweb. It is colourless, however, only when detached ; for
when adherent, it assumes the colour of the parts immediately
beneath it. Hence the green colour so prevalent in the leaf
and tender shoot, and the beautiful variety of hues displayed
in flowers and fruits.

Du Hamel, who seems to have been the first to study its
structure minutely, describes it as being formed of a multipli-
city of fine and delicate fibres, placed in a parallel direction,
but inosculating at regular intervals, so as to constitute a net-
work, the meshes of which are filled up with a thin and trans-
parent pellicle — single, as in the epidermis of the leaf; or di-
visible into several layers, as in the stem of the Paper Birch
Betula papyracea, in which you may count six or more*.

Saussure the elder inspected it as it occurs in the leaves
and petals of Jessamine and Foxglove, and describes it as
constituting a bark composed of two layers, the interior layer
being net-like, and interspersed with a multiplicity of what
he calls cortical glands, and the exterior layer being totally
destitute of organization f.

Hedwig describes it as forming a network of fibres that
consists of two distinct but adherent laminae ; but he regards
the cortical glands of Saussure as being merely pores or
apertures perforating the pellicle that fills up the mesh J.

Comparetti describes it as consisting of a network of fibres
ascending in an oblique direction, and forming hexagonal
meshes of various sizes and positions, the area of the meshes
being occupied by opake or transparent points, of an oval or
roundish figure, that seem to be somewhat inflated, as if filled
with air or water. He studied it chiefly as it occurs in the
leaves of succulent plants §.

The above descriptions do not, indeed, tally quite so com-
pletely as could be wished ; but an exact coincidence was
not to be expected in the description of an organ that differs
so much in different species of plants, and even in different
parts of the same plant. They agree in all that is essential.
Whoever will be at the trouble to repeat the observations will
find that the foregoing descriptions exhibit a sufficiently cor-

* Phys. des Arb., liv. i. chap. ii. f Obsei'vations stir P Ecorce de Feuilles.

X Tracts relative to Botany, 1805. § Senebicr, Phys. Veg.

Composite Organs of Plants. 183

rect view of the general aspect of the epidermis; and If he ex-
tends his researches further, he will very probably meet with
varieties of structure different from any that have been yet
specified. Nature loves to luxuriate in varieties, and further
varieties have been accordingly met with.

Mr. F. Bauer, of Kew, describes the cuticle of Doryanthes
hastata Correa as consisting of two or three stories of cells laid
one above another, and exhibiting in their aggregate aspect
a resemblance to that of a honeycomb. The epidermis of
the inner surface of the petals of Crocus vcrnus presents the
similitude, neither of a network of fibres, nor of stories of
minute cells, but of a thin and individual layer of parallel and
tangent reeds of unequal lengths, interspersed with multitudes
of minute and shining points, or molecules, and resembling a
front view of the false pipes of an organ. Finally, in the stem
and branch of woody plants, the epidermis often exfoliates,
and is again regenerated even if destroyed by accident; but in
herbaceous plants, and in the leaf, flower, and fruit of other
plants, the epidermis never exfoliates, and is never again re-
generated if once destroyed.

The Pulp. — The pulp, or cellular tissue, is a soft and succu-
lent substance, constituting the principal mass of herbaceous
plants, and a notable proportion of many parts even of woody
plants. It abounds in the seed-lobes and in succulent fruits,
of which any one may easily satisfy himself by cutting up,
whether in a longitudinal or transverse direction, a bean or
an apple recently gathered from the stalk or tree. It is also
particularly conspicuous in the leaf and flower, with their foot-
stalk, when stript of the epidermis. Nor is it wanting even
in the stem of woody plants, though it is cognizable, at least
as a separate organ, only in the pith or in the bark of the
young and tender shoots, where it constitutes a thin layer im-
mediately under the epidermis, and forms a sort of secondary
integument to the plant, known among botanists by the name
of the cellular integument. In the leaves its colour is generally
green, and in the seed-lobes white; while in flowers and fruits
it assumes almost all varieties of shade, according to the spe-
cies of plant, or according to the circumstances in which it is
placed. When viewed without the microscope its appearance
is that of an assemblage of small and minute granules, im-
bedded in a soft and glutinous substance, as in the greater
part of leaves and succulent fruits. But it is only when viewed
minutely with a good glass that its true structure is to be de-
tected. Malpighi describes it with his usual accuracy, and
compares it to an assemblage of inflated threads or bladders,
containing a juice. Grew describes it under the appellation

184? The Rev. P. Keith on the Internal Structure of Plants.

of the parenchyma, and compares it to the bubbles formed
upon the surface of liquor in a state of fermentation. Du
Hamel represents it as consisting of a sort of network of fi-
bres, crossing in all directions, and interspersed with small
and granular, or bladder-like substances occupying the inter-
stices.

Such are the descriptions of the earlier vegetable anatomists,
in one or other of which the general appearance of the pulp
will be found to be pretty fairly represented under whatever
aspect the botanical student may happen to meet with it. But
later anatomists have been more minute. Mirbel describes
it as being composed of clusters of small and hexagonal cells,
containing a juice. This was an important step in advance,
yet he obscures his description in the introduction of a useless
distinction, by which he divides his cellular tissue into a pa-
renchyma and a herbaceous tissue, the former containing a
coloured, the latter a colourless, juice. But an apparatus of
united cells, containing a fluid whether colourless or coloured,
is all that is necessary to form a true pulp. The cells he does
not regard as being distinct and individual organs, such as
might be insulated and shown separately, but merely as be-
ing formed of a fine and delicate membrane so folded or
doubled up as to leave the partitions single and common to
two cells. This doctrine Dutrochet has shown to be ground-
less, and if we repeat his experiment we shall come to the
same conclusion. Take a portion of pulp and put it into a
phial filled with nitric acid. Plunge the phial thus rilled into
boiling water, and the cells will soon become easily detach-
able, or will soon begin to separate and to present themselves
entire in their hexagonal form. Hence, where the walls touch,
the membranes must be double #.

Further, Mirbel regards the partitions of the cells as being
perforated by minute holes, or pores, for the transmission of
sap or other juices of the plant. Yet his doctrine of internal
and visible pores has not been generally adopted by other
vegetable anatomists. It was attacked and denied, rather
rudely, by the German doctors Sprengel and Treviranus,
and again affirmed and reasserted by Mirbel in his Defense
de ma Theorie, as well as by Link, Hedwig, and Rudol-
phi. But as the pores in question have been still more re-
cently and more laboriously searched for by M. Dutrochet
without success, I suppose we must be content to regard the
doctrine as unfounded. Dutrochet says the pores are merely
small globules imbedded in the walls of the cells f. It should

* Rccherches A?iatomiqucs, torn. xi. f Ibid. torn. xiii. p. 40.

The Rev. P. Keith on the Internal Structure of Plants. 185

be added, however, that Mirbel could not account for the
fact of the lateral transmission of sap, except through the
channel of visible pores ; while Dutrochet, by means of the
agency of molecular infiltration, can account for it very well
without them*.

The Pith. — The pith, as has been already shown, is a soft
and spongy, but often succulent substance, occupying the
centre of the root, stem, and branches, and extending in the
longitudinal axis of the plant, in which it is inclosed as in a
tube. Its structure is similar to that of the pulp, being com-
posed of an assemblage of hexagonal cells, containing for the
most part a watery and colourless juice. Mirbel regards it as
being furnished with pores like those already described; but
Dutrochet denies their existence, and contends that the fan-
cied pores are merely minute molecules imbedded in the walls
of the cells like those of the pulp. He designates them by
the name of nervous corpusclesf ; and affirms, besides, that
there is no pith in the root J. In many roots, we admit that
there is no visible pith ; but let any one examine the root of
Acorus Calamus or Berberis communis^ and then let him say
what he thinks of the affirmation.

Yet, if its structure is so very similar to that of the pulp,
why, it may be said, is it to be designated by another name?
The central situation of the pith is, perhaps, of itself a suffi-
cient reason. But there seems to be besides a difference of
texture in the membranes composing them. Let the juiceless
pith of the Elder or of the Bulrush be compared with the
withered pulp or cellular integument of the Lime-tree, and the
difference will be obvious.

The Cortical Layers. — The cortical layers, or interior and
concentric layers constituting the mass of the bark, are situ-
ated immediately under the cellular integument, where such
integument exists, and where not, immediately under the epi-
dermis, or they are themselves external. They are distin-
guishable chiefly in the bark of woody plants, but particu-
larly in that of the Lime-tree, in which they are easily sepa-
rated by maceration or exposure to the weather, and in which
you may readily count a dozen or more in a branch or trunk
of any considerable size.

In aged trunks the outer layers are coarse and loose in
their texture, exhibiting individually a conspicuous and con-
siderably indurated, but very irregular network, composed of
bundles of longitudinal or cortical fibres, not ascending the
stem directly, but winding more or less around the axis of

* Recherche* Anatomiqucs, p. 48. f Ibid. p. 13. \ Ibid. p. 46.

Third Series. Vol. 5. No. 27. Sept. 1834. 2 B

186 The Rev. P. Keith on the Internal Structure of Plants.

the plant. As the layers recede from the circumference, the
network which they form is finer, though still very irregular,
and their texture more compact. Yet the meshes of the dif-
ferent layers often correspond, and form, at least in aged
trunks, pyramidal apertures, or widen into large gaps or
chinks, as in the trunk of the Oak or Elm, exhibiting still the
rough traces of the original network. In young trees or shoots
the apertures formed by the coincidence of the meshes are not
yet left empty, but are occupied by a pulp, somewhat com-
pressed, which traverses the longitudinal fibres, and binds and
cements them together.

In all trunks the inner layers are soft, smooth, and flexible,
and capable of subdivision till reduced to an absolute film,
but not always exhibiting a conspicuous network. The inner-
most layer of all is denominated the liber, the Latin term for
a book, from its having been used by the ancients to write on
before the invention of paper*. It is the finest and most de-
licate of the layers, and is often most beautifully reticulated, as
in the liber of Daphne Lagetto, remarkable beyond that of all
other plants for the beauty and delicacy of its network, and
soft and flexible as the finest lace. If the cortical layers while
yet young are accidentally injured, the part destroyed is again
regenerated, and the wound healed up without a scar ; but
if the wound extends beyond the liber, the part destroyed is
no longer regenerated.

The Ligneous Layers. — The ligneous layers, or layers con-
stituting the wood, occupy the intermediate portion of the
stem between the bark and pith, and are distinguishable into
two different sets, concentric layers and divergent layers.

The concentric layers, which constitute by far the greater
part of the mass of the wood, may be seen on the surface of a
horizontal section of almost any trunk or branch, as on that
of the Oak or Elm, particularly after being for some time ex-
posed to the weather. They have been believed to be equal
in number to the years of the plant's growth ; but they are
not literally or strictly so. Neither are they literally or
strictly concentric. On the one side or on the other there is
generally an excess of width as well as of number, not ac-
cording as it is exposed to, or sheltered from, the light and
heat of the sun, as some writers have affirmed, but according
to the accidental situation of the great roots and branches.
The inner layers are the hardest and the outer layers the
softest, and the outermost layer, which is the softest of all, is

* Is not the converse of this the fact — Was not a book called liber be-
cause it consisted of the vegetable substance to which that appellation was
originally confined ? — Edit.

The Rev. P. Keith on the Internal Structure of Plants. 187

denominated the alburnum, till in the process of vegetation it
becomes an inner layer, in its turn, more solid and more con-
densed, and is ultimately converted into perfect wood.

The divergent layers, which intersect the concentric layers
in a transverse direction, constitute also a considerable pro-
portion of the wood, as may be seen on a horizontal section of
the stem of the Fir or Birch-tree, on which they present an
appearance like that of the radii of a circle. But if the wood
is split longitudinally, fragments of the divergent layers will
be seen adhering to the surface of the fracture, in the form
of large and smooth plates, which interweaving themselves
among the concentric layers, in the manner of an irregular
wickerwork, form a sort of tense binding, that cements and
unites the whole. This appearance is peculiarly conspicuous
on the riven surface of the Elm-tree or of the Oak.

In following up the analysis of the ligneous layers you
cannot separate the two sets, so as to exhibit each of them
entire ; but as the divergent layers are soluble in certain fluids
in which the concentric layers are not soluble, the latter
may be exhibited pretty entire by means of the destruction of
the former. That which seems at first sight to be merely
an individual layer, proves upon further inspection to be a
group consisting of component layers, finer and smaller still,
till at last you can follow the division no further. Du Hamel
macerated a piece of the trunk of an Oak-tree in water, with
a view to dissolve the divergent layers, and found, after a
long time, that the minuter divisions of the concentric layers
consisted ultimately of an assemblage of longitudinal or woody
fibres, so as to form a network similar to that of the liber.
The root of the Artichoke, after being pulled up out of the
soil, and exposed for a considerable time to the action of the
atmosphere, affords, perhaps, the most beautiful of all exam-
ples of this sort. It separates, thus, into thousands of layers
of network, each as fine and as delicate as a piece of Brussels
lace.

Yet this mode of analysis gives us no knowledge of the
structure of the divergent layers. We must consequently
have recourse to the aid of the microscope. Take a minute
slice of a divergent layer from the riven surface of an Oak or
Elm, and put it under a good glass, and you will find that it
has the appearance of being composed of an assemblage of
parallel fibres, or threads of contiguous vesicles not forming
a network, but closely crowded together, and compressed into
a thin plate. It is apparently nothing more than the vesicles
or cellular tissue of the pulp that existed originally in the
alburnum, now deprived of its parenchyma, or contained fluid,

2B2

188 Mr. W. G. Horner's Considerations relative to

but still filling up the interstices of the concentric layers, and
binding them together, according to the similitude of Grew
and Malpighi, as the woof of a web binds together the longi-
tudinal threads of the warp.

[To be continued.]

■ - - ■ ■ . - '.'■" •-- -sr

XXVII. Considerations relative to an interesting Case in

Equations, By W. G. Horner, Esq.*
"DERCEIVING that Professor Moseley has resumed the
-*• development of the principle of least pressure, I presume
that the discussion, which was introduced by Mr. Earnshaw,
respecting the validity of the ^principle, has terminated.
Without entering, therefore, upon the general question, in
the fate of which I have no other interest than every lover of
science must be supposed to have, I may be allowed to ex-
press my disappointment at the unsatisfactory result of that
portion of the argument which, if conclusively handled, was
likely to have proved the most impressive. I allude to that
passage in which the Rev. Professor's reasoning assumed the
tangible form of an equation. That this was regarded by
both the disputants as a critical point, is abundantly apparent;
and, in fact, if the general theory is " such, in its nature, as
cannot be submitted to the test of experiment t", it is doubly
requisite that the testimony of calculation should be clear.
For these reasons, the liberty which I use in recalling atten-
tion to that particular point will be the more readily excused
by the gentlemen who have already agitated the question.

In page 200 of the Number of this Magazine already re-
ferred to, Mr. Moseley, in considering the case of " a pressure
equally divided between three points of support in the same
right line," gives the following as " the two equations of equi-
librium :"

u — + T + s= M

x x—b x—c

= Ma."

a:— b x—c

The resultant of this pair of equations he finds, with the tacit
assent of Mr. Earnshaw, to be a mere quadratic, which, how-
ever, seems to have been regarded by each party as having but
one root; and in consequence of this complicated oversight, the
dispute settled down into a discussion of the point of legitimacy

* Communicated by the Author.

f See Phil. Mag. and Annals, March 1834, p. 194.

an interesting Case in Equations. 189

between two roots, neither of which has been proved to be re-
levant to the argument. What is still more strange, that root
which has been most strenuously claimed as auxiliary to one
side of the cause, proves to be quite adverse to it. Under all
the circumstances, it is not without a sentiment approaching
to diffidence that I venture to make these assertions; and
especially because the objections I have to offer to the method
employed in reducing the proposed equations are so palpable,
that it is difficult to dismiss the notion that they have been
considered and overruled; but on what sound principle of
reasoning I cannot conjecture.

1. If the equations contain but one unknown quantity, one
of them suffices for the solution, and the other is either super-
fluous or contradictory ; and so, a fortiori, is the third equa-
tion, which has been derived from them.

2. If two unknowns are involved in each equation, either
two new equations must be formed by elimination, or if only
one subsidiary equation is employed, the result must at all
events be introduced into the original statements.

3. A third exception applies to the mode of obtaining the
subsidiary equation, namely, by taking the quotients of the
separate scales. If it were stated that Xs = «, and x = b>

would it follow that .\ x* = -^-, and x = + »/ -r-? As-
suredly not.

4. This objection is still more valid when the quantities
exterminated by division are zero or infinite. That this im-
pediment exists in the present instance will appear on adopt-
ing a mode of reduction exempt from the faults above re-
cited ; e. g.

Dividing by a, the equations become

± + i + _L_ . M (i.)

X x—b x—c u

x—b x—c
Deducting (2.) from a times (1.),

Ma
a

(2.)

«+«=»+«=?. 0 (3.)

x x—b x—c

To prove this to be a complete cubic equation, it would be
abundantly sufficient to make x = ,f' u and reduce. The

1 90 Mr. W. G. Homer's Considerations relative to
result would be a cubic, complete in all its terms. In fact,
merely say x m — , and we have

a — b a—c

f a — o a — c \ _ ,A x

U+l — j— + ) z = 0 ... (4.)

v 1 — bz \—czi v

which, when cleared of fractions, will be an equation of three
dimensions.

If the parenthetic portion of (4.) is made = 0, and re-
duced, the result will be a quadratic agreeing w7ith Mr. Mose-
ley's. But here is, besides, a third root, z as 0, which gives

1 M

x = — and — = 0 in each equation (1.), (2.). Q. E. D.
0 a

Again, this infinite x not only solves both the original
equations, it does so to the exclusion of any other infinite x
presumed to be deducible from any relation incident to a, b, c.
For it reduces (1.) (2.) (3.) to simple and dependent equations,

3 ^ b + c _■ Sa — b—c , . , „

viz. — = 0, = 0, = 0, which all merge in

XX x

— = 0 ; the condition 3#— b~ c = 0 being quite superfluous
x
and nugatory.

M

In some views of the equation — = 0, upon which the in-
finity of x depends, physical and analytical considerations are
inseparable, and results are obtained which confirm what has
just been alleged; e.g, it distinctly announces either that
the mass M has absolutely no weight, or else that the standard
moment of pressure a is infinite. The latter is of course the
alternative to be preferred, as it cannot be Mr. Moseley's de-
sign to discuss the relations of weight and pressure in masses
absolutely destitute of weight. But if a is infinite, what be-
comes of its constancy ? " Let a represent a constant quan-
tity." Or, granting that, what becomes of the quantities

A = — , B = r, C = ? Can they be severally af-
ar x—b x—c J <

firmative and infinite, although their sum is = the finite
quantity M ? If not, x must have been infinite from the first,
and irrespectively of a9 b9 c.

After all, the only way of arriving at conclusions perfectly
satisfactory is by regular elimination ; the labour of which,
even by the easiest methods, is in this instance considerable.
I have, however, undertaken it, not only for the sake of epi-

an interesting Case in Equations. 1 9 1

tomizing the present argument, but in the hope of supply-
ing students with a pretty addition to their collections of ex-

ec

amples. Reducing (1.), (2.), and makings = ^, s m b -f- c,

p = b c9 the equations to be solved are

x3— (s + 3y)x* + (p + 2sy) x — py = 0 (A.)

*<-{,- f)x+(P+*M) =o (ft)

Eliminating y by the method of the common measure, we find

(3a— s)x*— %(as— p)x + ap = 0 (C.)

as determined by Mr. Moseley. But if we also eliminate x
by the method of combinations, we obtain a formula in y
which, when arranged, resolves itself into the factors

(♦P-rfW ji. Q (D>)

a3 v

and
3(3a — s) j/2— 2(3a2— 2as+p)y + (a*— as-\-p) a = 0 (E>

Of these, equation (D.) shows that y = 0 yields two solu-
tions, which are readily found to be x = b9 x = c. But when
these values are placed in (1.), (2.), the conditions appear to be
rather eluded than satisfied, the equations being reduced to
a balance of infinity.

Equations (C.) (E.) being compared, in the event of s = 3 a,
which leads to infinite values of x and y9 which answer to
each other, and finite values which likewise correspond, give
in the former case x = 3 y. The same result is obtained di-
rectly from either (A.) or (B.), their mutual independence and
their dependence upon a, b9 c9 being simultaneously destroyed
by the same hypothesis, viz. that of the infinity of x9 neces-
sarily involving that of y.

jy 2 ft3 a

The corresponding finite values are y = * 2__ . — , and

x = , /__ ., which appear, therefore, to furnish the only

legitimate solution of the pair of equations in the event which
has been insisted upon.

It is for Mr. Moseley to determine how far his principle is
affected by these results. My concern has been to solve a
curious difficulty connected with equations in a case where
the application of some of the ordinary rules has proved illu-
sive. The general equation, of which (3.) is a partial case,
deserves attention.

[ 192 ]

XXVIII. Observations on the Spectra of the Eye and the Seat
of Vision. By Mrs. Griffiths.*

To the Editors of the Philosophical Magazine and Journal.
Gentlemen,
HP HE main object which induced me to communicate the

■*■ curious discovery of the vision of the retina, was to elicit
the attention of the English philosophers to that part of it
which related to the seat of vision. This question has been
lost sight of entirely; and although I have been gratified with
the zeal with which Sir David Brewster has pursued the ex-
periment, yet it has taken a different course from the one I so
much desired.

In the remarks on my communication, the Editor observes
that " some of the conclusions in the paper, especially those
about the seat of vision, are not correct." It is not specified
in what the error consists. I assert on good grounds that the
office of the retina is to contract and dilate the pupil. When
the pupil contracts, the intersections or meshes of the retina
are elongated, and of course they are thinner, and the inter-
stices or squares between are larger. When the pupil dilates,
the lines, or meshes, or intersections, whatever they may be
called, are thicker, and the spaces between are smaller.
Surely this proves that the retina is of an elastic nature, and
its office is sufficiently well denned. ^

Is it philosophical to suppose that a part of the eye so sin-
gularly constructed can transmit the impressions of external
objects to the sensory ? It is composed of squares, with re-
gular intervals of interstices, and these squares are for ever
varying with every change of light ; in which way, there-
fore, could this separate apparatus transmit all the various
forms which are presented by external objects ? Perhaps there
is no portion of the eye so little adapted to the purpose of
transmitting objects or impressions as the retina, and I would
enlarge on this point did I not think that some abler pen
would soon appear to discuss the matter in a fuller form. I
wish the fact to be established, that the seat of vision does not
belong to any one part of the eye in particular, but that the
whole apparatus of the eye is necessary to the conveyance of
external impressions to the sensory.

I consider the eye, as it respects mental vision, as an ex-
ternal object, and that under different modifications of light
every portion of it can be seen. For instance,Mr.W.G. Horner
can see the " blood-vessels of the retina." I can see the retina,
the opening of the pupil, the crystalline lens, the air-bubbles

• See Lond. and Edinb. Phil. Mag. vol. iv. pp. 43, 115, 241,262, and
354.— Edit.

Mrs. Griffiths on the Spectra of the Eye and Seat of Vision. 193

in the aqueous chamber; the aqueous humour itself flowing in
and circulating incessantly; the fixed spots on the outer sur-
face of the crystalline lens ; and the connected floating links
of air-bubbles, which, when numerous, cause the disease in the
eye called amaurosis #.

The whole apparatus of the eye is therefore, to the mina\
of no more importance than the internal machinery of a watch
is to the hour-hand of the dial-plate. The machinery of the
watch and of the eye is in constant motion, but no one part of
either is the direct cause of the movement of the hour-hand,
or of the perception of impressions.

The mind sees the time as specified by the motion of the
hands, and the mind has the perception of impressions as spe-
cified by the simultaneous operations of the different portions
of the eyeball. By inspection, all the machinery of the watch
is visible to the mind, and by inspection, all the machinery of
the eye is visible to the mind likewise.

The impression of external objects is instantaneous, and is
not transmitted from the object to any one particular part,
and thence to the sensory. Vision is impaired when any one
part of the eye is diseased, although the retina, so universally
admitted to be the seat of vision, is in a healthy state.

The physiological or mechanical seat of touch lies at the
end of the fingers, at the ends of the toes and tongue, and in
the lips, that is, the qualities of bodies are rendered percep-
tible to the sensory through the agency of these parts of the
body. No one supposes that the seat of touch resides in any
particular part of the skin itself, whether finger, tongue, or
lip. The sensation of touch is produced by direct pressure,
a pressure which is instantaneous, which commences at the
point of contact, and ends in the brain, whence the mind takes
immediate cognizance of it.

So it is with all the senses ; there is an instantaneous com-
munication between the outward points which come into con-
tact with tangible bodies and their qualities, and the central
point in which consciousness dwells.

Seeing, being the most complicated of all the senses, re-
quires a more complicated apparatus to convey impressions to
the mind. The different parts are for the admission, the modi-
fication, and the absorption of light, whilst amongst this curious
machinery the adjustment and continued action of these se-
veral parts are maintained by certain muscular and valvulous

* We apprehend that this is not the case. Although it is certainly stated
by some medical writers that the appearance of these muscce volit antes t as
they are termed by pathologists, indicates in certain cases the commence-
ment of amaurosis, yet they do not, we believe, actually constitute any form
of that disease. — Edit.

Third Series. Vol. 5. No. 27. Sept. 1834. 2 C

194- Mrs. Griffiths on the Spectra of the Eye and Seat of Vision.

movements, all necessary to the due transmission of impres-
sions from without.

It is not, therefore, that part of the machinery of the eye
called the retina which first receives the impressions from
without, although it is an expansion of what is called the optic
nerve. There is still an agent unknown to us, which, in all
cases of the different senses, conveys the impression of external
bodies and their qualities to the sensory or consciousness.
The retina acts no more in the transmission than what is ef-
fected by the pressure of the finger when we wish to inform
the mind of the quality of any body. For if the contractile
power which conveys the sensation of qualities be not likewise
an expansion of the same nerve, originating in the same cen-
tral point whence the optic nerve emanates, yet it most as-
suredly operates by virtue of the same principle or power
which transmits the different sensations that the qualities and
appearances of bodies produce.

Of one thing we are now certain, that the seat of vision lies
beyond the machinery of the eyeball ; for by repeated observa-
tion and experiment I can see almost every portion of it.
This does not arise from any imperfection or obliquity of vi-
sion ; for my eyes are, and always have been, in a healthy
sound state. I am only sorry that I did not commence the in-
vestigation at an earlier period. It remains still a matter of
doubt with me, whether an eye younger than forty can be
sensible to the appearances which those beyond that age are
capable of comprehending. I do not say that the eye must be
injured by disease, for old age is not a disease, but I suspect
that an eye in full vigour has all its parts so nicely adjusted,
and the elasticity is so on the qui vive, that there is an inti-
mate adhesion and blending of the whole machinery, no one
portion of which is more relaxed than the other.

Nine or ten years ago I discovered that, by placing the light
of a candle at a certain distance from the eye, and allowing it
to fall obliquely— as I stated in p. 306. of Our Neighbourhood*
— on the cornea, I could see part of the interior of my own eye.
I recollect drawing a map of the spectrum as it invariably
appeared, and several years after I showed it to Dr. Hosack.
Since that period I can bring the spectrum to my mind either
with the eye half closed or nearly open, either by means of a
candle, or from a ray of sun-light. I subjoin a map of the
spectrum as it appears in both eyes, for, as happens to Mr.
Horner, each eye presents a somewhat different appearance.

The spots in the margin are dark in the centre, with a halo
of paler light around them. The golden appearance of the

* The title of a Novel by Mrs. Griffiths.

Mrs. Griffiths on the Spectra of the Eye and Seat of Vision. 195

oblong drops in the centre answers to what Mr. Horner calls
" golden rain"; but the brilliancy and golden hue originate
in the colour of the light, for a ray of the sun gives it a silver
colour. I have described the whole in p. 306. of Our Neigh-
bourhood. At first, before T could keep my eye steady, I
only saw the quarter, and oftentimes a very small sector, of the
spectrum; now I see the whole at once.

Right Eye. Left Eye.

In front of this spectrum are to be seen, as below in No. 1 .
and No. 2., the loose air- bubbles and connected links, all
moving various ways and changing their position and con-
nexion with one another every instant.

No. 1.

In No. 1. I have merely represented the water which flows
in the aqueous chamber ; in No. 2. I have represented the
transparent air-bubbles, and the links of these same bubbles.
They are sometimes so fine as to have the appearance of a
transparent cambric thread. All these are perpetually float-
ing about in the fluid of No. 1., which is in constant motion,
rising and falling like waves.

In a future communication I shall give you these images
very highly magnified, but at present I thought it better to
show them as they appear by the aid merely of the magnifying

8 v 2

1 96 Mr. J. Bryce's Addendum to a Descriptive Catalogue

power of the eye itself. As soon as sufficient attention has
been excited towards this curious phenomenon, I shall give
the world a new discovery in this branch of optics, one so very
curious that it deserves to be ushered into notice when the
mind has contemplated all the preparatory steps which your
knowledge shall make familiar.

It is not mere speculation when I assert that the office of
the retina is to regulate the admission of light. I go on safe
grounds : experiment has convinced me that the lines which
compose the meshes of the retina are thicker or thinner as
the opening of the pupil varies. In some future communica-
tion I will show you one of these meshes magnified. Mr.
Horner is correct in saying that the eye sustains no injury
in making these experiments.

The brilliancy of colouring and the kaleidoscope patterns
of which Sir David Brewster speaks, belong exclusively to
the peculiar shape and structure of the retina. With all the
multiplied and various experiments that I have made, I have
observed that all the brilliant as well as opake figures are
square or angular. I have never seen anything approaching
to circularity but the stars which I have described in my first
paper. That star, or those stars, for there is one in the centre
of each square or mesh, may be in reality composed of points
or angles, but they are too minute to ascertain this fact.
They scintillate.

XXIX. Addendum to a Descriptive Catalogue of the Minerals
of the North of Ireland. By James Bryce, Jun.9 M.A.,
KG.S.,$c.

To the Editors of the Philosophical Magazine and Journal.
Gentlemen,
T N a note appended to a paper of mine on the minerals of
-*- the North of Ireland, published last August, you inquire,
in relation to a new mineral, which Dr. Thomson has named
hydrocarbonate of lime and magnesia, " Whether this mi-
neral is allied to that which the late Mr. W. Phillips, at the
suggestion of Mr. Brayley, described under the appellation of
Hydrocarbonate of Lime, in the last edition (1823) of his
Elementary Introduction to Mineralogy, p. 161." It is then
added, from a communication by Mr. Brayley, that the latter
mineral " is the result of the action of the trap dykes of the
Giants' Causeway upon the chalk which they have intersected,
and, according to the analysis of the late Dr. Da Costa, would
appear to be composed of four atoms carbonate of lime and
there atoms water," &c. In reply I may observe, that I be-
lieve the minerals to be distinct, though obviously closely al-

of the Minerals of the North of Ireland. 19*7

lied. That analysed by Da Costa occurs wherever the trap
dykes cut the chalk*. Dr. M'Donnell, who first noticed this
mineral, informs me, that it was pronounced to be dolomite by
several skilful mineralogists and chemists to whom he showed
it at various times. The analysis of Da Costa, however, gave
no magnesia. The other mineral yielded to Dr. Thomson
some portion of that earth. It has been found only at Down-
hill in Derry, in veins and irregular masses in an amygdaloid
of a loose texture, accompanied by zeolites and the common
carbonate of lime. On these grounds I think the two minerals
may be regarded as distinct; an analysis of the magnesian one
will most probably be given in full in the work on mineralogy
for some time expected from the pen of the distinguished
chemist just named. In the System of Professor Mohs, and
the excellent "Manual," by Robert Allan, Esq., just published,
this and several others, usually described as distinct, are
classed under calcareous sparf.

It was stated in the " Catalogue," that the large crystals of
quartz so frequent at Dungiven were found in a trap rock.
I believe this is inaccurate. Some of the crystals are found in
the bed of the river Roe, which is partly primitive ; others are
found in the debris of mountains of the basaltic range, but
have most probably been transported thither by currents from
the primitive country to the west. Small crystals of quartz,
however, are frequent in our trap rocks. Hydrolite and
levyne have been recently found in other places within the
basaltic district besides Island Magee, and anhydrous disili-
cate of iron in dykes and loose boulders of trap near Larne.
Mr. M'Adam suggests that it ought to have been mentioned
in the " Catalogue," as a remarkable circumstance, that the
magnetic or octahedral iron ore found by him in the Isle of
Muck, occurs only on the external surface of the rock.

The researches of Lieut. James, R.E., in the county of
Down, and the zealous labours of Mr. Patrick Doran in all

* It perhaps ought to be observed, that this mineral may have been
found in the vicinity of the Causeway, but certainly not immediately there ;
because there is no chalk at the Causeway, nor, so far as I am aware, at
any place in the trap district where columnar basalt exists. In such a case
that rock rests on lias or sandstone.

f [We are obliged to Mr. Bryce for his reply to our inquiry. We do
not know what edition of Prof. Mohs's System he may refer to, but in
Haidinger's Translation neither of the minerals in question is adverted to,
either by name or by implication ; nor would it be in accordance, we think,
with Prof. Mohs's principles of classification, to include them ** under
calcareous spar " : the other minerals " usually described as distinct " but
which are also regarded by that mineralogist as varieties of calcareous spar,
consist, essentially, like that mineral, of carbonate of lime alone, and are
also connected with it into one species by gradual transitions of external
character, or by what in Zoology and Botany is termed affinity— E. W. B ]

198 Prof. Young on the Development of certain

parts of the country, have added some new and very interest-
ing minerals to our former catalogue. The following is a
list of these :

Var iolite.— This variety of compact felspar has been lately
met with in the hornblende rock of Morne.

Anthracite. — A compact variety of this mineral, with a
highly metallic lustre, occurs frequently in the grauwacke of
Down.

White Carbonate of Lead — accompanies galena and the green
phosphate of lead in the Newtonard's lead-mine, Down.

Colophonile. — This mineral occurs in quartz veins travers-
ing siliceous slate near Glassdrummond, Morne. It is of a
brownish yellow colour, and is crystallized in rhombic do-
decahedrons, with very unequal angles, and having striae pa-
rallel to the lesser axis of the rhomboid. The mineral has
very much the appearance of cinnamon stone.

Sulphuret of Molybdena. — This mineral has been lately dis-
covered in a siliceous slate, or, I believe, rather a chlorite
slate, on the shore near the mountains of Morne. The cry-
stalline form is a six-sided table, terminated by a low six-sided
pyramid, of which the base angles are truncated. Neither
this mineral nor the colophonite have, so far as I know, been
before noticed in Ireland. Yours, &c.

Belfast, Aug. 11, 1834. James Bryce, Jun.

XXX. On the Development of certain Trigonometrical Func-
tions. By J. R. Young, Professor of Mathematics in the
Royal College, Belfast,*

T^HE series given by analytical writers for the development
•*• of a circular arc in terms of its sine, cosine, and tangent
are as follows :

si„-i* = ,+ £jjL + x*£^6 +, &c.

-i * & 3xb

cos lX S3 x 4- — 4-. &c

—1 X3 Xb X

tan-1* = x — 4- — — - 4-, &c.

which series, as well as those for the development of the arc
in terms of the other trigonometrical lines, are true only for
the least of the arcs to which these trigonometrical lines be*
long. I am not aware that any explanation has ever been
given of this want of generality ; or that any one has made
known how it comes to pass, that while the developments of

* Communicated by the Author.

Trigonometrical Functions* 1 99

sin x, cos x, &c, in terms of x are true in all cases, yet the de-
velopments of the inverse functions, which, a priori, we should
expect to possess equal generality, turn out to be true only
in one particular case. In allusion to this circumstance La-
croix remarks : u Les series qui expriment sin x et cos x par
Tare, sont plus generates que leurs inverses, qui expriment
Tare par le sinus ou le cosinus : les dernieres ne conduisent
qu'au plus petit des arcs qui ont le meme sinus ou le meme
cosinus, tandis que les premieres donnent le sinus ou le co-
sinus, quel que soit celui de ces arcs qu'on prenne pour x" —
Lacroix, Calcul Diffi et I?it.9 torn. iii. p. 620.

Now it is the object of this short paper to show that the
series for sin""1,r, cos-1^, &c, when properly investigated,
possess the same generality as those for sin x9 cos x, and that
the defective forms above arise from an oversight committed
in the analytical processes whence they are deduced.

If we turn to Lacroix, or to any other writer on the Cal-
culus, we find the investigation of the development of y =
sin_1.r conducted as follows :
y = sin""1 x

g = (!-**)-* +3** (-**)-*
&c. &c.

The values of these expressions for x = 0 are said to be

i. dy „ tPy > <Py

and hence, by Maclaurin's theorem, the first of the above
developments is inferred. Now when x = 0 it is not neces-
sarily true that y = 0; it is true only when the proposed arc
is less than a quadrant. If the arc be greater than a qua-
drant, and terminate in the second quadrant, then the value
of it for x = 0 can obviously be no other than y = v; if it
terminate in the fourth quadrant, its value for x = 0 must be
y = 2 it ; if in the fifth, y = 3tt, and so on*. It must also be
observed that when the arc terminates in the second quadrant,

* We are here considering only the positive arcs; the negative arcs
having the same sign will terminate in the 3rd, 4th, 7th, &c, quadrants,
going round the circle in the opposite direction ; and the corresponding
values of y> for x = 0, will obviously be — tt, — 2 ?r, — 3tt, &c, the sam«
as before, but with opposite signs.

200 Prof. Young on the Development of certain

-t—-, and therefore the following coefficients, are negative ;

when it terminates in the fourth quadrant they are positive, as
at first; when in the fifth negative, and so on. Hence the
general expression for the development of sin-1 x, terminating
in the k+ lth quadrant, is

r ifi 3g,r5 3959*7 ; x \

**±{*+ I^+l^X5+1.2.3.4.5.6.7 + &C'i
the upper sign being used when k+l is odd, and the lower
when it is even, £+1 being either positive or negative.

The series for y = cos""1^ is inferred from the following
conditions, which are said to have place when x = 0, viz.

T-z ^---i ^/-o^-i&c

sin-1 .27

2' rf* "" ' do?* ~ ' d

But the first of these conditions is true only when the pro-
posed arc, 3/, terminates in the first quadrant. If it termi-

3fl"
nate in the fourth, y must be ^r— , when x = 0 ; if it termi-

m

nate in the fifth, y must be %—— ; if in the eighth, y must be

sr* and so on. Moreover, in the fourth quadrant -^-. —4,
2 *■ ax ax*

&c., have signs contrary to those which they have in the first ;
in the fifth the signs are the same as in the first; in the eighth
opposite, and so on. Hence the general expression for the
development of cos-1 x, is

cos * .r= hr

the arc terminating in the &+lth quadrant; the upper sign
being used when k+l is odd, and the lower when it is even.
It is obvious that if the arc be negative this expression will
take the minus sign.

By attending to similar considerations we shall find, for the
development of tan-1 .r, the general expression

17 X* X5 X7 Q

tan"1 .r = fcTT + x — - + — — -f, &c,

o o 7

the arc always terminating in the 2 £4- 1th quadrant.

The development of tan""1^ is frequently deduced by the
aid of a certain logarithmic formula, without the application
of the calculus; the resulting form is, however, limited to the
single case above mentioned ; and this limitation arises, as in
the former process, from an oversight in the investigation, al-
though one of a very different kind. The investigation we

Trigonometrical Functions, 201

have in view is as follows. Setting out from the known for-
mulas— (See Young's Dili*. Calc, p. SO.)

ex+Aii _ CQS x^_ ^ __^ sm x

e—x*/—\ __ CQS ^ _ y^ __j# sm ^

and taking the logarithms, we have

x \f — 1 = log (cos x + ^ — 1 . sin x)

—x s/ — 1 = log (cos x — s/ — 1. sin #) ;

therefore, by subtraction,

a / — r , COS.T+ \/ — \. smx , 1 -f s/ — 1. tan x

2x v — 1 = log ■ == ss log = .

cos x — s/ — 1 . sin .r 1 — \/ — 1 . tan *

Now, log j— = 2 |« + — + T + T + ,&c.|

hence, substituting */ — l. tan ,r for w, we have

/ — r . ^ tan3 jc tan5 x tan7 # 0 ? ' — -
2x\/ — 1 = 2]tan.r 1 h,&c>\/— 1

tan3 # . tan5 x " tan7 .r , 0
.•. # = tan x - 1 = 1 = h> &c.

o o (

The reason that we have obtained this defective form arises
from an omission in the general expression for the logarithm

of , which omission would lead to no error if we were

dealing with real quantities only. It was proved by Euler,
that every number has, besides the logarithm usually consi-
dered, an infinite number of others, all imaginary*: thus, if
we represent the usually received value of log A by Log A,
then will the general expression for log A be

log A = Log A + 2 kir\/ — I.
When, therefore, we are dealing with imaginary quan-
tities, we are not warranted in omitting the imaginary values
of log A, as is done in the foregoing process. Restoring, there-
fore, what has been improperly omitted, we have

log \£ -V{«f -! + f + f +, &c.} MW%

* This may be proved as follows. By Young's Calculus, page 33,
»J —\ •=. e% •• — 1 = e .*.!=<? .*. A = Ar

e

.'. log A = log A + 2 h x J- 1.

Third Series. Vol. 5. No. 27. Sept. 1834. 2 1}

202 On the Development of certain Trigonometrical Functions.

— f tan5 x tan5 a: \ ~\

.\ 2x*/~- 1 = 2 < tan* — f — &c.J^ \/ — I

tan3.r tan5J7 0 .

.•. x = tan x - 1 r , &c, + kit

as before obtained.

Many other developments, besides this, are deduced in an
incomplete form from neglecting imaginary logarithms. Take
the following from among many that might be selected. La-
croix, at p. 1 36, vol. i. of his Calculus, develops the expres-
sion ( */~\) 'v'"-1 as follows :

Substitute \/ ^l for u in the known formula
log u = u ~ w-1 - 1 (w9-«-2) + i (us-u-3) -, &c,
and it becomes

logV"=l = • ~i-^^-4"(~1 + 1) + t(-*'-1

+

— 2 it it

.-. v^llog V~\ = - \ .'.(i/^l)V"1=^"s"-
This result is incomplete, for it is known that

* ' 4*+l

and this is the result which we should have obtained if the
imaginary quantity 2 k it V — 1 had not been improperly
omitted ; for we should then have had

log v/^1 = y s/~\ + 2kit ^/^i

(4/^l)*/-i = e-

4**1
S

jr.

These instances not only verify Euler's theory of imaginary

Improvement in Say's Instrument/or taking Specific Gravities. 203

logarithms, but at the same time show their use in analytical
investigations.
July 1834. J. R. Young.

XXXI. Description of an Improvement in the Construction
of Say's Instrument for measuring Specific Gravities, By
W. H. M.*
A DESCRIPTION of this instrument as originally con-
££• structed, and which might with more propriety be called
an instrument for measuring volumes, is given by its
inventor, M. Say, a French officer of engineers, in ^Q-,
one of the volumes of the Annates de Chi?niefor 1797
(xxiii, i.), and also by Mr. Faraday in his work on
Chemical Manipulation. The annexed figure repre-
sents the instrument in its improved form. ABare two
glass tubes, of 0*2 inch internal diameter, one 34 and
the other 35 inches long, placed close together, and
having their lower ends cemented into an iron cap,
into the lower end of which an iron stop-cock is ^
screwed. The upper end of the longer tube is ce-
mented into the bottom of a cup B, having its rim

ground truly plane, the capacity of which is a little in D

more than half that of the tube. The tubes are L.

fixed parallel to a graduated scale, carrying a sliding
vernier D, provided with an index formed of two
slips of brass, one before and the other behind the
tubes, having their lower edges in a plane perpen-
dicular to the scale. E is a piece of plate-glass, having
its lower surface greased, and large enough to close
the mouth of the cup B. The instrument may either
be fixed permanently in a vertical position against
a wall, like a barometer, or else may have a broad foot with
three screws, by which it may be rendered vertical for use.

The substance to be examined, which may be any solid
liquid or powder that is not volatile, is placed in a small cup,
which goes into the cup B. The stop-cock at A is closed, and
mercury is poured through a small funnel into the shorter
tube till it rises to a mark on the longer tube at P ; the
mouth of the cup B is then closed, so as to be air-tight, by
the plate of glass E. The stop-cock must now be opened,
and the mercury permitted to escape in a small stream till
its surface in the longer tube stands about 15 inches higher
than in the shorter tube, when the stop-cock is to be closed.

* Communicated by the Author.
2 D2

204- Improvement i?i Say 's Instrument/or taking Specific Gravities*

Lastly, the depths of M and C, the extremities of the columns
of mercury in the tubes, below the mark at P, are to be mea-
sured by means of the scale and sliding-index.

Let v be the volume of the substance examined, u the space
occupied by the air between E and P before the substance is
placed in the cup, h the atmospheric pressure expressed in
the height of the column of mercury, of the same temperature
as the mercury in AB, which it supports.

At the commencement of the observation, when the surface
of the mercury was at P and the cup B closed, the air be-
tween E and P occupied a space = u — v9 and its pressure
was measured by // ; when the extremities of the columns of
mercury in the two tubes are at M and C, the air which was
in B occupies a space = u — v + vol. PM, and its pressure is
measured by h — MC.

Hence, by Hooke's law,

u — v + vol. P M h

u — v ~ h- MC

h - MC , . '^L
•'• v = u MC~ ( )#

When the bore of the longer tube is very uniform, and the
area of a perpendicular section of it = K, we have

h-UQ
v =: u ^j£- K . PM.

The value of u may be found by a similar process, the cup
being empty. K is readily deduced from the weight of a
column of mercury of known length contained in the longer
tube.

If the weight of the substance be also known, its specific
gravity can of course be easily calculated.

The advantages which the instrument here described pos-
sesses over that of M. Say, appear to be: (1.) It is only half
the length of Say's, and requires no complicated frame-
work for its support. (2.) The heights of the columns of mer-
cury may be measured with great accuracy with the vernier.
In Say's, the fractions of a division on the scale can only be
obtained by estimation. (3.) By making both tubes of the
same diameter, the effect of capillary depression is completely
eliminated ; while in Say's its amount, more especially in the
space between the tubes, can never be accurately allowed

for.

W. H. M.

[ 205 ]

XXXII. Phytological Errors and Admonitions. By the Rev.
Patrick Keith, F.L.S.*

HPHE profound research, the acute discrimination, and the
■*■ eloquent expression of facts, of arguments, or of opinions
displayed in the writings of M. De Candolle, have obtained
for their author a high and well-merited reputation, whether
as a botanist or phytologist; so much so, that we shall not
err if we apply to him the well-known maxim of Horace,
which says,

Cui lecta potenter erit res,

Nee facundia deseret hunc, nee lucidus ordo.

De Art. Poet. 40.

I had been repeatedly led to make this application of the
maxim in perusing different portions of his Physiologie Vege-
tate; but especially in a late perusal of the Considerations
Preliminaires which he affixes to that work, and in which he
presents to the notice of the reader a succinct and correct
view of the true principles of phytological investigation, mark-
ing specifically the path to be pursued and the errors to be
avoided. The structure of the several organs of vegetables,
as in a state of rest, is the first branch of the study of the
phytologist— that is, the anatomy of the plant ; their agency
in the ceconomy of vegetation is the second — that is, the study
of the forces with which the organs act, or by which they are
acted upon. In the former case we are to explore with the
most rigid scrupulosity their hidden and internal structure ;
in the latter, we are not to ascribe to the vital energies of the
plant effects that are merely tissual on the one hand, or
chemical on the other ; nor to its tissual or chemical properties,
effects that are merely vital ; but we are to be careful to assign
to every effect its true and proper cause f.

Here we have, doubtless, the golden rule of all phytologi-
cal investigation. Yet the investigator can make use of it
only according to the best of his ability ; and in the difficulty
of accounting satisfactorily for the various phaenomena of ve-
getation, it is not surprising that phytologists should have been
occasionally seduced into error, and led to assign effects to
wrong causes. The grand stone of stumbling is to be met
with in accounting for those effects which are evidently vital,
and in which the life of the vegetable seems to approximate
closely to that of the animal. This is the respect that has led
phytologists to overstep the limits which bound the legitimate
scope of vegetable investigation, and to ascribe to vegetables
faculties, the existence of which is at best but extremely du-
bious. Tissual susceptibilities did not seem to them sufficient

* Communicated by the Author. f Phys, I'cgct., torn, i. p. 6.

206 Rev. P. Keith on Phytological Errors, with Admonitions.

to account for certain phsenomena of vegetable life, and hence
they assumed the aid of susceptibilities of a higher order, — sus-
ceptibilities which in the animal subject are termed cerebral.
Yet the leading advocates of this opinion have not been no-
vices ; they have not been men of mean reputation, whether
in literature or in science ; they did not take up the doctrine
at random ; they took it up deliberately and advisedly, and
hence their opinions are entitled to our respectful considera-
tion. Among them we find the names of Bonnet, Watson,
Percival, Darwin, Smith. We do not say that M. De Can-
dolle's notice of them is not respectful; but he regards the
doctrine as supported more by arguments drawn from imagi-
nation and feeling, than from reason and experience, that is,
from the heart rather than from the head*; and whether this
implies anything of a compliment, we leave the reader to de-
termine.

I find that my name is associated, in a foot note, with that
of Bonnet, Percival, and Smith, not for having defended the
doctrine of vegetable sensibility, I presume, for that I evi-
dently controverted, but for having mooted the question in
my System of Physiological Botany, and for maintaining, or
seeming to maintain, a doctrine that may be said to imply
sensation, namely, that of a vegetable instinct. At a loss to
account for the singular, and hitherto inexplicable fact of the
irresistible descent of the radicle, in the process of germina-
tion, through the intervention of any cause, whether chemical
or mechanical merely, I thought it was not absurd to suppose
in the vegetable subject, the existence and agency of a cause
analogous to that of instinct in the animal subject, but not
identical with itf . But although a zoologist is allowed the
aid of instinct to account for the unaccountables of the animal
ceconomy, yet let me admonish the phytologist who has any
respect for the opinion of the critics, to beware how he lays
claim to the aid of an analogous principle to account for
the unaccountables of the vegetable ceconomy. He will be
set down immediately as a fool or a blockhead. His case is
without remedy, and his sentence without mercy. He will
be told that the doctrine "is palpably inadmissible;" that
" it is absurd;" and that " it is merely a betraying of his
ignorance of the cause." Did Newton know the cause
which he points out to our notice by the term gravitation ?

* Phys. Veget., torn. i. p. 29.

t [Agreeing entirely with Mr. Keith in this view of the subject, we may
add, further, (adopting Maclean's distinction of relations of analogy from
those of affinity, and employing a new word much wanted,) that this vege-
table principle, though strictly analogous to instinct, is not merely not iden-
tical but not even affinal with it. — E. W. 13.]

Rev. P. Keith on Phytological Errors, with Admonitions. 207

He knew merely the laws by which a certain principle acts,
and he gave it a name. Beyond that he knew nothing. The
same is the case with the physiologist who talks of a vital
principle, and with the phytologist who ascribes the descent
of the radicle to a cause analogous to that of animal instinct.
He knows very well that he is ignorant of the cause any
further than as producing effects that can result only from the
exertion of the vital energies of the plant; and to the energies
thus exerted he gives the name of instinct. The best and
most acute of our phytologists have felt the strong leaning that
exists in the human mind to the admission of some such prin-
ciple. What says Dutrochet in his Observations sur la Motilite
des Vegetans? " En voyant cette diversite de moyens employes
pour parvenir a un meme fin, on serait presque tente de croire
qu'il existe la une intelligence secrete qui choisit les moyens
les plus convenables pour accomplir une action deter minee."
(p. 132.)

For myself, I have abandoned the use of the term instinct
entirely ; not because the admission of vegetable instinct is a
confession of our ignorance of the cause, — for it is better to
confess our ignorance of a cause than to adduce a false one, —
but because it is a term calculated to mislead the phytological
student, as being so long usurped by the zoologist, and a
term, the legitimate use of which seems to me to be that of
the denoting of the act of an individual being regarded as
sentient, rather than that of the denoting of the growth of any
organ or fabric, whether animal or vegetable. Hence, as I
disclaim the doctrine of vegetable sensation *, I disclaim, of
necessity, that of vegetable instinct also.

Still I cannot adopt the opinion of those who ascribe the
descent of the radicle merely to the force of gravitation. To
me the phenomenon seems to be essentially a vital process,
which the phytologist is not to confound with any process
that is essentially either chemical or mechanical. This is an
error, against the commission of which M. De Candolle is at
great pains to guard his reader in his Considerations Frelimi-
nairesf, and yet, after all, he no sooner finishes his admoni-
tions than he seems to me to fall into it himself; for he an-
nounces his adoption of Mr. Knight's theory of the descent of
the radicle, — that is, the accounting for a vital phenomenon
upon a principle merely mechanical f.

It is not my intention to enter into the merits of Mr. Knight's
hypothesis at present : a more convenient season may arrive.
What I have to remark now is, that M. De Candolle, on what

* Phil. Mag. and Annals, N.S., April 1832.

t Ptys. Feget., torn. i. p. 7- % Ibid., torn. i. p. 30 ; ii. p. 821.

208 Rev. P. Keith on Phytological Errors, with Admonitions,

ground I know not, unless as involved in the theory of Mr.
Knight, adopts an additional opinion, which I cannot help re-
garding as erronepus also. It is the opinion by which vege-
tating roots are supposed to receive their increments of length
solely by the extreme points. " Les racines ne s'alongent
que par leur extremite*." That this was the result of some
experiments of Duhamel and of Mr. Knight, we do not mean
to deny; but it is good only as far as it goes. You are not to
deduce from it a rule for all plants whatever. If you do so,
you embrace a manifest error which I did my best to expose,
so long ago as 1819, in a set of experiments published in
No. 76 of Dr. Thomson's Annals of Philosophy. Yet I
do not find that any one ever condescended to notice them, or
to embrace the truth which they establish on account of them.
Truth, lovely though she be, if she hopes to be well received,
must come with a recommendation in her right hand, that is,
a recommendation from some great and acknowledged autho-
rity ; for there are many sciolists who would rather be in the
wrong with a writer of high reputation than in the right with
one of minor celebrity. Yet I find that Mr. Lindley has at
last taken up the subject, and exposed the erroneousness of
the old opinion f, so that from henceforward it is to be be-
lieved that botanists will no longer be found to cling to this
palpable error. " On the 5th of August," says Mr. Lindley,
" I tied threads tightly round the root of a Vanilla, so that it
was divided into three spaces, of which one was 7 inches long,
another 4 inches, and a third, which was the free growing
extremity, 1 inch and fths. On the 19th of September the
first space measured 7J inches, the second 4f inches, and
the third, or growing, 2£ inches." A root of Aerides cor-
nutum gave a similar result, and established the fact of the
general elongation of the root in the plants specified. Yet
Mr. Lindley gives all the weight that is due, or perhaps even
more than is due, to the experiments of Duhamel and Mr.
Knight; for he thinks it is possible that the peculiarity of
elongation by the extreme points may be universal in exoge-
genous plants. But the experiments which I instituted on the
radicle of the bean show that it is not.

"On the first of October 1818, I sowed some tick beans
in a small earthen pan filled with garden mould.

" On the fourth the radicle of the most forward had pro-
truded about -i-th of an inch beyond the integuments, when I
marked it with ink at the point, in the middle, and at the base,
as clearing the integuments ; so that the marks were about
-j^th of an inch from each other.

* Phys. Vegct., torn. i. p. 41 ; ii. p. 822. 1 tntrod., p. 228.

Rev. P. Keith on Phytological Errors, with Admonitions. 209

" On the fifth the radicle was |th of an inch in length, and the
marks nearly as before with regard to their relative distances,
but removed evidently from the integuments, so as to admit
a fourth or additional mark adjoining the integuments. The
radicle, which was originally upright, was now bending down.

" On the sixth the radicle was •§■ an inch in length, the first
mark being within two or three lines of the point; the second
at about Jth of an inch from the first ; the third at about £th
of an inch from the second; and the fourth at about Jth of
an inch from the third, as well as perceptibly removed from
the integuments.

"On the seventh the radicle was fths of an inch in length.
The first mark was still within two or three lines of the point ;
the second was at the distance of Jth of an inch from the first;
the third was at the distance of 5th of an inch from the second ;
and the fourth was at about £th of an inch from the third,
being but little more than its original distance, but removed
to the distance of £th of an inch from the integuments.

" On the eighth the radicle was one inch in length, the first
mark being still near the apex; the second at the distance of
about Jrd of an inch from the first; the third at the distance
of ^rd of an inch from the second ; and the fourth nearly as
before.

"On the ninth the radicle was \\ inch in length, the three
marks next the base being nearly as before, and the mark next
the apex being the only one that was carried down.

" On the tenth, and as long as any further observations were
made, it was still the lower extremity of the radicle that was
carried down. But enough had been previously observed to
show that the assumed peculiarity of the elongation of the ra-
dicle is founded in a mistake; and that the root in its incipient
state, like the stem in its incipient state, is augmented by the
introsusception and deposition of additional particles through-
out its whole mass, or 'by a general extension of parts al-
ready formed,' though it may afterwards, like the stem, be-
come so firm and compact as no longer to admit of augmen-
tation in that way*."

As connected with the presumed mode of the root's aug-
mentation, M. De Candolle takes occasion to speak of the
spongioles in which the small fibrils of the root terminate.
He represents them as being composed essentially of a cellu-
lar tissue. " Les spongioles des racines sont essentiellement
composees de tissu cellulairef." Yet this account of their in-
ternal structure does not seem to me to accord well with the

* Annals of Phil., No. 76. t Phi/s. Veget., torn. i. pp. 71, 41*

Third Series, Vol. 5. No. 27. Sept. 1834. 2 E

210 Rev. P. Keith on Phytological Errors, with Admonitions,

facts of the case, at least as they have presented themselves
to my inspection. To me the spongioles seemed to present
the palpable rudiments of a vascular tissue also.

It had been asserted by Duhamel and others, that the ex-
treme fibrils of the roots of plants die annually, in the winter,
and are renovated in the spring, in the manner, it may be
presumed, of leaves. Mr. Knight admitted the position with
regard to bulbous roots, but denied it with regard to the
roots of trees. To satisfy myself on this point, I took up por-
tions of the roots of several different plants, trees chiefly,
which brought the structure of the spongioles unavoidably
under my notice.

On the first of September 1828, I took up a portion of the
root of a plant of the horse-chestnut, which had come up from
seed in the preceding spring. The fibrils, which were for the
most part in a vigorous state, presented the appearance of a
cylindrical mass of pulp, of a whitish colour, inclosing a firm
and central filament, and terminating ultimately in an enlarged
and flattened point, — the spongiole of De Candolle, — which,
when cut open, was found, as well as the rest of the fibril, to
inclose a fine and central filament, or rather a bundle of such
filaments united into one cord, like the filaments that compose
the nerves of animals. A few had begun to decay, and their
decay was indicated by the shrinking and shrivelling up of the
external and pulpy mass. But if some were thus in decay,
others were beginning to shoot out fresh and vigorous from
the larger divisions of the chevelure, so that there was no ap-
pearance of the commencement of any regular denudation of
the root, whether by the decay of fibril or of spongiole.

On the 17th I took up the whole plant, and the appearances
were as before.

On the 15th of November I took up a plant of dwarf box,
but did not find a single fibril in decay. The newly formed
ones were covered with a white, dense, and fine down through-
out the greater part of their length, but at the origin and
point they were smooth. They were also more tapering than
those of the horse-chestnut, and had less of the club-shaped
appearance.

On the 28th I took up part of the root of an apricot, but
found no fibril wholly in decay. The outer coat of some of
them was indeed in decay, but the central filament was still
full of moisture, and a new coat forming.

On the first of December I had some portions of the root
of an elm-tree taken up, at about ten or twelve feet from the
caudex. They were well furnished with fibrils, many of
which were in decay, but their loss was more than compen-

Geological Society. 2 1 1

sated by a new and vigorous progeny, protruding, like little
buds, from the surface of the larger divisions. Like those of
the horse-chestnut, they terminated ultimately in a soft bibu-
lous and club-shaped appendage, or spongiole, furnished with
a central filament, that seemed to inclose others still smaller.
The external and pulpy coat of the spongiole was often found
to be in decay, while the inclosed and central filament was
still quite sound.

From the above observations respecting roots, the two fol-
lowing inferences are obviously deducible.

I. The root is never wholly denuded of its fibrils, or spon-
gioles, as the branches are denuded of their leaves. A partial
decay, with a partial renovation of these organs, seems to be
occurring at all seasons; but a total denudation of the root
occurs at no season. If, with Mr. Knight, we admit of a total
denudation of bulbous roots, I think it will not go beyond
such as are taken up out of the soil for the winter; for if the
bulb is allowed to remain in the earth, it is to be believed that
new fibrils will have begun to be protruded before the old
ones have finally decayed.

II. Spongioles cannot be said to be very well described by
representing them as composed merely of a cellular tissue,
for surely the central filament is to be regarded as exhibiting
the rudiments of a vascular tissue also ; and if in some cases
it is so very fine and minute as to be scarcely perceptible,
still it is abundantly perceptible in the cases now specified.
I regret, however, that I have not had access to a copy of M.
De Candolle's Organographies for there, I doubt not, the
structure of spongioles is more minutely detailed, and in such
a way, perhaps, as might have precluded the necessity for any
particular remark. What I have said is founded on such re-
presentations of the structure of the spongiole as are to be
met with in his Physiologie Vegetate.

Charing, Kent, Aug. 1st, 1834. P. Keith.

XXXIII. Proceedings of Learned Societies.

1834. A PAPER "On the Quantity of Solid Matter sus-
Feb. 26.—^- pended in the Water of the Rhine," by Leonard
Horner, Esq., F.G.S., F.R.S., was first read.

The experiments referred to in this paper, were made by the
author at Bonn, in the months of August and November. The ap-
paratus which he used was a stone bottle capable of containing
about a gallon, and furnished with a cork covered with greased

* Continued from p. 70.
2E2

2 1 2 Geological Society.

leather, having a long string attached to it. A weight was sus-
pended from the bottle by a rope of such a length, that when the
weight touched the ground, the mouth of the bottle was at the de-
sired distance from the bottom of the river. The cork was then
removed by the string, and the instant the bottle was full it was
drawn up.

The first set of experiments was made in August, at 165 feet
from the left bank of the river, and at 7 feet from the surface,
or 6 feet from the bottom. The Rhine was unusually low, and
the water was turbid and of a yellowish colour. The quantity
of solid matter obtained from a cubic foot of water, and slowly
dried, was 21*10 grains, or about T^-frm-th part. The residuum
effervesced briskly with diluted muriatic acid, was of a pale yel-
lowish-brown colour, smooth to the touch, and in appearance and
properties undistinguishablefrom the loess of the Rhine Valley.

The second set of experiments was made in November on water
taken from the middle of the river, and about one foot below the
surface. A great deal of rain had fallen some time before, and
also fell during the experiment. The water was of a deeper yellow
than on the former occasion, but when taken up in a glass was not
very different in appearance. The residuum of a cubic foot weighed
35 grains, or the -i-g-.Vrnrth part. The author then enters into an ap-
proximate calculation of the medium quantity of earthy matter borne
down by the Rhine during 24? hours. He assumes that the annual
mean breadth of the river opposite Bonn, is 1,200 feet, the mean
depth 15 feet, the mean velocity 2-fr miles in an hour, and the
average amount of solid matter held in suspension to be 28 grains
in the cubic foot of water. From these data he deduces the result
that 145,981 cubic feet of solid matter are borne past Bonn every
24 hours.

A paper was next read, entitled, " Observations on the Geo-
logical Structure of the Neighbourhood of Reading," by J. Rofe,
Esq., and communicated by Robert Hunter, Esq., F.G.S.

This communication was accompanied by a collection of fossils
from the neighbourhood of Reading, and was prepared by the
author chiefly to point out the localities and geological connexions
of the specimens; but he also describes some beds belonging to
the plastic clay, which are not mentioned in the published accounts
of the district.

In detailing the section presented by the Katsgrove pits, he
states, that the upper part of the chalk is perforated to about the
depth of a foot by tubular cavities resembling those made by the
Teredo in wood. The oyster-bed, which rests upon the chalk, he
says, is divisible into two parts, each about a foot thick, the lower
consisting principally of brown clay, and the upper of the sand
containing green particles. Above this bed the author observed
about a foot and a half of clay, and in the quartzose sand resting
upon it a layer of ochreous nodules. The account given by Dr.
Buckland of the strata above the one last mentioned*, the author
Fays is correct, with the exception of a thin bed of shells which

* Geological Transactions, 1st series, vol. iv. p. 278.

Geological Society, 213

occurs about 6 feet from the top of the section, and which is not
mentioned in Dr. Buckland's paper. This bed was also noticed by
Mr. Rofe in many other places in the immediate neighbourhood of
Reading, and at Woodley Lodge, about three miles to the east of
the town. At the latter locality the order of the beds is as follows :

Blue clay, about 40 feet.

The shelly stratum.

Mottled clay 55 —

Ditto, occasionally sandy. ... 35 —

In conclusion, the author states that all the wells in Reading,
excepting those supplied by land-springs, both on the north and
south of the Kennet, and even within 30 yards of its banks, are
regulated by the Thames, rising and falling with that river. This
phenomenon, he conceives, may be accounted for, by the Kennet
flowing over a bed of tenacious clay, whereas the Thames flows
over gravel resting immediately upon chalk, into which the wells
are sunk.

March 12. — A paper was read, entitled, " Observations on the
Temple of Serapis at Pozzuoli, near Naples ; with Remarks
on certain Causes which may produce Geological Cycles of great
Extent. In a Letter to W. H. Fitton, M.D., from Charles Babbage,
Esq."

The author commences this paper with a general description of the
present state of the Temple of Serapis, and gives the measurement
of the three marble columns which remain standing, and which,
from the height of 11 feet to that of 19, are perforated on all sides
by the Modiola lithophaga (of Lamarck) ; the shells of that animal
remaining in the holes formed by them in the columns. A de-
scription is then given of the present state of twenty-seven portions
of columns, and other fragments of marble, and also of the several
incrustations formed on the walls and columns of the temple.

The conclusions at which the author arrives are —

1. That the temple was originally built, at or nearly at the level
of the sea, for the convenience of sea-baths, as well as for the use
of the hot spring which still exists on the land side of the temple.

2. That at some subsequent period the ground on which the
temple stood subsided slowly and gradually ; the salt water, entering
through a channel which connected the temple with the sea, or
by infiltration through the sand, mixed itself with the water of the
hot spring containing carbonate of lime, and formed a lake of
brackish water in the area of the temple, which, as the land sub-
sided, became deeper, and formed a dark incrustation.

The proofs are, that sea-water alone does not produce a similar
incrustation ; and that the water of the hot spring alone produces
an incrustation of a different kind ; also, that Serpulae are found ad-
hering to this dark incrustation ; and that there are lines of imter-
level at various heights, from 2*9 feet to 4?'6 feet.

3. The area of the temple was now filled up to the height
of about seven feet with ashes, tufa, or sand, which stopped up the

2 it Geological Society.

channel by which sea-water had been admitted. The waters of
the hot spring thus confined converted the area of the temple into
a lake, from which an incrustation of carbonate of lime was depo-
sited on the columns and walls.

The proofs are, that the lower boundary of this incrustation is ir-
regular ; whilst the upper is a line of water-level, and that there are
many such lines at different heights ; — that salt water has not been
found to produce a similar incrustation ; — that the water of the
Piscina Mirabile, which is distant from the sea, but in this imme-
diate neighbourhood, produces, according to an examination by
Mr. Faraday, a deposit almost precisely similar; — that no remains
of Serpulse, or other marine animals, are found adhering to it.

4% The temple continuing to subside, its area was again par-
tially filled with solid materials ; and at this period it appears to
have been subjected to a violent incursion of the sea. The hot-
water lake was filled up, and a new bottom produced, entirely co-
vering the former bottom, and concealing also the incrustation of
carbonate of lime.

The proofs are, that the remaining walls of the temple are
highest on the inland side, and decrease in height towards the sea
side, where they are lowest ; — that the lower boundary of the space
perforated by the marine Lithophagi is, on different columns, at dif-
ferent distances beneath the uppermost or water-level line; — that
several fragments of columns are perforated at the ends.

5. The land continuing to subside, the accumulations at the
bottom of the temple were submerged, and Modioli attaching
themselves to the columns and fragments of marble, pierced them
in all directions. The subsidence continued until the pavement of
the temple was at least nineteen feet below the level of the sea.

The proofs are derived from the condition of the columns and
fragments.

6. The ground on which the temple stood appears now to have
been stationary for some time, but it then began to rise. A fresh
deposition, of tufa or of sand, was lodged, for the third time, within
its area, — leaving only the upper part of three large columns visible
above it.

Whether this took place before or subsequently to the rise of
the temple to its present level, does not appear; but the pave-
ment of the area is at present level with the waters of the Mediter-
ranean.

The author then states several facts, which prove that consi-
derable alterations in the relative level of the land and sea have
taken place in the immediate vicinity. An ancient sea-beach ex-
ists near Monte Nuovo, two feet above the present beach of the
Mediterranean ; — the broken columns* of the Temples of the Nymphs
and of Neptune, remain at present standing in the sea ; — a line of
perforations of Modiolae, and other indications of a water-level 4<
feet above the present sea, is observable on the sixth pier of the
bridge of Caligula ; and again on the twelfth pier, at the height of

Geological Society, 2 1 5

10 feet ; — a line of perforations by Modiolae is visible in a cliff op-
posite the island of Nisida, 32 feet above the present level of the
Mediterranean.

The author considers the preceding inferences as a legitimate
induction from the observed and recorded facts; and proceeds
to suggest an explanation of the gradual sinking and subsequent
elevation of the ground on which the temple stands. From some
experiments of Col. Totten, recorded in Silliman's Journal, he has
calculated a table of the expansion, in feet and decimal parts, of
granite, marble, and sandstone, of various thicknesses, from 1 to
500 miles, and produced by variations of temperature of 1°, 20°,
50°, 100°, 500° of Fahrenheit : and he finds from this table, that if
the strata below the temple expand equally with sandstone, and
a thickness of five miles were to receive an accession of heat
equal only to 100°, the temple would be raised 25 feet;— a greater
alteration of level than is required to account for the phenomena
in question. An additional temperature of 50° would produce the
same effect upon a thickness often miles; and an addition of 500°
would produce it on a bed only a single mile in thickness.

Mr. Babbage then adverts to the various sources of volcanic
heat in the immediate neighbourhood : and he conceives that the
change of level may be accounted for by supposing the temple to
have been built upon the surface of matter at a high temperature,
which subsequently contracted by slowly cooling down ; — that when
this contraction had reached a certain point, a fresh accession of
heat from some neighbouring volcano, by raising the temperature
of the beds again, produced a renewed expansion, and which re-
stored the temple to its present level. The periods at which these
events happened are then compared with various historic records.

The second part of this letter contains some views, respecting
the possible action of existing causes, in elevating continents and
mountain-ranges, which occurred to the author in reflecting on
the preceding explanation. He assumes as the basis of this rea-
soning the following established facts:

1. That as we descend below the surface of the earth at any
point, the temperature increases.

2. That solid rocks expand by being heated j but that clay
and some other substances contract under the same circumstance.

3. That different rocks and strata conduct heat differently.

4. That the earth radiates heat differently, or at different parts of
its surface, according as it is covered with forests, with mountains,
with deserts, or with water.

5. That existing atmospheric agents and other causes, are con-
stantly changing the condition of the surface of the globe.

Mr. Babbage then proceeds to remark, that whenever a sea or
lake is filled up, by the continual wearing down of the adjacent
lands, new beds of matter, conducting heat much less quickly than
water carries it, are formed ; and that the radiation, also, from the
surface of the new land, will be different from that from the water.
Hence, any source of heat, whether partial or central, which pre-

2 1 6 Geological Society.

viously existed below that sea, must beat the strata underneath
its bottom, because they are now protected by a bad conductor.
The consequence must be, that they will raise, by their expan-
sion, the newly formed beds above their former level j — and thus
the bottom of an ocean may become a continent. The whole ex-
pansion, however, resulting from the altered circumstances, may
not take place until long after the filling up of the sea; in which
case its conversion into dry land will result partly from the filling
up by detritus, and partly from the rise of the bottom. As the
heat now penetrates the newly formed strata, a different action
may take place ; the beds of clay or sand may become consoli-
dated, and may contract instead of expanding. In this case,
either large depressions will occur within the limits of the new
continent, or, after another interval, the new land may again sub-
side, and form a shallow sea. This sea may be again filled up
by a repetition of the same processes as before : — and thus alter-
nations of marine and freshwater deposits may occur, having inter-
posed between them the productions of dry land.

Mr. Babbage's theory, therefore, may be thus briefly stated. —
In consequence of the changes actually going on at the earth's
surface, the surfaces of equal temperature within its crust, must
be continually changing their form, and exposing thick beds,
near the exterior, to alterations of temperature; the expansion
and contraction cf these strata will probably form rents, raise
mountain-chains, and elevate even continents. — The author admits
that this is an hypothesis ; but he throws it out, that it may be sub-
mitted to an examination which may refute it if fallacious, — or, if
it be correct, establish its truth, — because he thinks that it is de-
duced directly from received principles, and that it promises an
explanation of the vast cycles presented by the phenomena of
geology.

March 26. — A letter was first read from Charles Denham Or-
lando Jephson, Esq., M.P., F.G.S., to George Bellas Greenough,
Esq., P.G.S., " On Variations of Temperature in a Thermal Spring
at Mallow."

The observations recorded in this letter were made principally
during the autumn and winter months of 1833. The extreme
variations were 67° and 710tV» the difference depending in Mr.
Jephson's opinion on the quantity of water acted upon. From
80 to 100 yards north of the spring at which the observations
were made, are other thermal springs, the temperature of which
is 1° higher, and from 60 to 80 yards to the south is a cold spring,
having a temperature of 54-°. The formation from which the waters
issue is limestone.

A letter was then read from William Henry Egerton, Esq.,
F.G.S., addressed to Charles Lyell, Esq., For. Sec. G.S., " On
the Delta of Kander."

The Kander in its ancient course flowed parallel to the Lake of
Thun, and emptied itself into the Aar, beyond the village of
Heiraberg j but in consequence of the injury done to the land by

Geological Society . 217

its frequent inundations, the Government of Bern determined to
direct its waters into the lake of Thun. This object was finally
accomplished about the year 1713, by making two parallel tunnels,
about a mile in length, between the original course of the river and
the lake; and no sooner was the Kander admitted into them than
it burst up the arches, tore away the masses of rock which ob-
structed its passage, and bore a vast heap of gravel and detritus
into the lake. The delta thus commenced, and increased by the
sedimentary matter brought down during nearly 120 years, now
presents a tract covered with trees, extending about a mile along
the original shore, and a quarter of a mile from it into the lake.
The depth of the ravine by which the Kander now enters the lake
is 50 feet. The depth of water at the part occupied by the delta
Mr. Egerton could not ascertain, but, from the declivity of the
ancient banks, he conceives that it must have been consider-
able, and Saussure found some parts of the lake to be 350 French
feet in depth. The author determined by actual measurement the
angle at which the new deposit dips beneath the waters of the lake,
at the extremity of the delta. At 30 yards from the shore, he
found 14- fathoms of water; at 60 yards, 23 fathoms, and at 120
yards no bottom at a depth of 82 fathoms.

A communication by Colonel Sykes was then read, entitled, " A
Notice respecting some Fossils collected in Cutch by Captain Smee,
of the Bombay Army."

The district from which the specimens were procured is situated
between the 23rd and 24th parallels of N. lat. and 70th and 71st
degrees of E. long., and is bounded on the E. and S. by the Run.
The fossils consist of four species of Ammonites, one of Trigonia,
two of Astarte, one of Corbula, one of Gryphaea, and a coral
having a nummulitic form. One of the Ammonites has a general
resemblance to A. Wallichii, and another agrees in some respects
with A. Nepalensis, both of which occur in the fossils procured in
the Himalaya range ; one specimen of the Gryphsea is stated to
resemble closely the Gryphsea of the Oxford clay of England ; and
the coral belongs to the genus which occurs in the Kressenberg iron
ore. Specimens of silicified wood, lignite and alabaster from Cutch
were also exhibited, and of durable oolite from near Poorbunda, on
the W. coast of the peninsula of Goojrat ; and it is stated that the
same rock is found abundantly at Raujcote in the centre of the
peninsula. In conclusion, Colonel Sykes observes, that if English
analogies may be taken for a guide, the district from which the
above fossils were obtained would seem to be composed of second-
ary rocks, as Ammonites, Trigonia, and Gryphaea have not been
found in England higher than the upper chalk.

A paper was afterwards read " On the Gravel and Alluvial De-
posits of those Parts of the Counties of Hereford, Salop, and
Worcester which consist of Old Red Sandstone ; with an Account
of the PufFstone, or Travertin of Spouthouse, and of the South-
stone Roch near Tenbury, by Roderick Impey Murchison, Esq.,
V.P.G.S.

Third Series. Vol. 5. No. 27. Sept. 1834. 2 F

2 1 8 Geologica I Society.

The district of which the transported materials are described
is bounded on the west by the transition rocks, extending from the
environs of Ludlow to the S.W. of Kington, and on the E. by the
Abberley Hills, thus including a large portion of the trough of old
red sandstone. It is shown that all the detritus within these limits
has been derived from the adjacent rocks. In the neighbourhood
of Kington bowlders of the contiguous trap rocks are found upon
the talus of the Ludlow rocks, extending to the edge of the old
red sandstone, and in the plain W. of Ludlow the surface of the
old red is frequently covered with coarse gravel, in which are
numerous fragments of the trap rocks of the W. of Shropshire, In
general, however, the gravel is chiefly made up of the debris of trans-
ition rocks, the coarser varieties being found only near the boun-
dary of those formations. Detailed sections are given in the neigh-
bourhood of Ledbury ; and the valley of the Teeme is particularly
described to prove that, on receding from the transition chains,
the gravel becomes more finely comminuted, and exhibits near
Tenbury the characters of lacustrine or fluviatile sediments, the
materials of which consist exclusively of fragments of the surround-
ing rocks of old red sandstone.

Two remarkable cases of a modern travertin, 5 and 8 miles E.
of Tenbury, are then cited, the one near the Spouthouse farm, the
other the Southstone Roch, both of which have been accumulated
in narrow dells, which intersect transversely promontories of the
old red sandstone. At the former the travertin is associated
with much sandy marl. The latter is a cavernous rock of about
50 feet in height, and has a superficies of more than a quarter of
an acre, having on its surface a small house and garden. In both
cases the travertin incloses Helices of existing species, and has
been occasionally quarried for purposes of building and burning
to lime.

These modern rocks are shown to have been formed by small
springs which issue from the calcareous or cornstone strata of
old red sandstone, and still encrust the leaves and grasses over
which they flow, a process which the author (judging from the
size of the rocks produced) supposes to have been in undisturbed
action during the whole period of history.

Although no bowlders of foreign rocks are to be found in the di-
stricts above described, it is stated that on the northern confines of
the old red sandstone near Bridgenorth and Wenlock, there are many
large fragments of granite of various sorts. These are also seen in
abundance on the flanks of the Wrekin, but they are not to be
traced into the area of the old red sandstone, and as they are
entirely different from any of the Welsh rocks, the author refers
them to a northern region. In conclusion, it is suggested that the
superficial accumulation of the old red sandstone of Salop, Here-
fordshire, and Worcestershire may be referred to causes in opera-
tion during three epochs, which may hereafter be divided into other
distinct periods.

1. To the currents caused by the elevation of the adjacent

Geological Society, 2 1 9

transition rocks of Wales, when the associated volcanic action was
in full activity.

2. To the subsequent degradation of the old red sandstone,
both when submarine and during its elevation.

3. To various alluvial causes, of date posterior to the desicca-
tion of the old red sandstone, including the erosion of rivers, the
deposits of partial lakes, and the accumulation of travertin.

April 9. — A paper was first read, entitled " A short notice of
the Coast Section from Whitstable in Kent to the North Foreland
in the same County," by William Richardson, Esq., F.G.S.

The author commences his memoir by describing the changes
which the line of coast has undergone ; and he states that many parts
of it, as Hearne Bay and the Old Haven, near Bishopstone, have
completely lost the features to which they owe their appellation.
He then enters into a minute detail of the London and plastic clays,
of which the district is principally composed. He shows that the
former constitutes the whole of the cliffs from Whitstable marshes
to Hearne Bay, and the upper part of that to the eastward of it.
The clay he divides into two portions j the higher contains much
sand and green earth, and is occasionally marked with patches
and streaks of light blue or green clay; and the lower preserves
the usual characters of the formation. The only organic remains
which he noticed were fragments of wood, teeth of fishes, and por-
tions of an Encrinite and of Pentacrinites sub-basaltiformis. Iron
pyrites and selenite are stated to abound in every part of the clay,
and amber and jet to be occasionally found in it. A minute de-
scription is given of the Septaria, which are said to be very numerous
and to have the surface often covered with small ramifications re-
sembling branches flattened by pressure.

Of the plastic clay formation only the sandy portion is said to occur
on the coast. It first appears to the east of Hearne Bay rising from
beneath the London clay at an angle of about 5°, and extends to
Birchington, where it is succeeded by chalk. It contains beds of
pebbles and friable sandstone inclosing shells. Sectional lists are
given of the cliff near Bishopstone, and of that on which the Recul-
ver Towers are situated ; and the author rectifies the error in the
" Outlines of England and Wales," where it is stated that the Re-
culver cliff is composed of London clay. The fossils mentioned in
the paper are confined to the genera Venus, Cerithium and Trochus,
and the remains of fishes. The chalk which forms the coast from
Birchington to the North Foreland is mentioned only for the pur*
pose of showing that it declines to the westward at the same angle as
the superior formations. A bed of brown loam containing a few
flints is described as covering the surface of the London and plastic
clays, and to be thickest in those parts where the cliffs rise to the
greatest height. The vast accumulation of bones in the oyster-bed
opposite Swale Cliff is also described, and among those obtained by
the author are the remains of the elephant, horse, bear, ox and
deer.

2F2

220 Geological Society.

A paper was afterwards read, " On the several Ravines, Passes,and
Fractures in the Mendip Hills and other adjacent Boundaries of the
Bristol Coal-field, and on the geological Period when they were ef-
fected," by the Rev. David Williams, F.G.S.

The district included in this memoir comprehends the western
portion of the Mendip Hills, and the western and north-western
boundaries of the Bristol coal-field. It presents a series of lofty ridges
composed of mountain limestone and traversed by deep transverse
ravines which connect the valleys on the opposite sides of the ridges.
The author describes, in great detail, the characters, both physical
and geological, of each ravine j and shows that in consequence of
their being filled, in part, with horizontal beds of dolomitic conglo-
merate, red marl, and lias, they were formed previously to the
deposition of those formations ; but he also shows that the ravines
have been subsequently acted upon by a body of water, forming
what he terms valleys of denudation in valleys of elevation.

In describing thedefile of St. Vincent's Rocks, near Bristol, the
author states, that he has discovered two lines of fracture indepen-
dent of the one noticed in the memoir of Dr. Buckland and Mr.
Conybeare on the south-western coal-field*. He says that the prin-
cipal evidence which he has of the existence of these two faults,
rests on the beds of clay, belonging to the lower limestone shale,
occurring twice on both sides of the ravine between the first fault
and the commencement of the shale beds in their true position
beneath the mountain limestone.

In alluding to the bone-caves and fissures of the Mendip Hills,
the author conceives that they were formed contemporaneously
with the ravines ; and that he had found among their organic
contents the remains of the Mastodon.

April 23.— A paper was first read, i( On the Tertiary Forma-
tions of the Kingdom of Murcia, in Spain," by Charles Silvertop,
Esq., retired Brigadier in the Spanish Service, K. R. O. C. III.,
F.G.S.

This memoir is a continuation of papers on the tertiary formations
of the South of Spain, read before the Society during the last and
preceding Sessionsf. The district described is situated in the south-
eastern portion of the kingdom of Murcia, and consists of extensive
plains and valleys of tertiary formations, bounded by discontinuous
ridges of mica slate, transition rocks, and nummulitic limestone.
The tertiary deposits the author divides into four districts, which
he names from the principal towns situated in their immediate
neighbourhood, viz. Lorca, Totana, Alhama and Mula, and Car-
tagena.

The tertiary strata of Lorca he separates into two systems, one
characterized by the beds being horizontal, the other by their being
highly inclined. The horizontal beds consist of reddish friable

* Geol. Trans., 2nd Ser., vol. i. p. 241.

t See Phil. Mag. and Annals, N.S., vol. vii. p. 453; vol. viii. p. 150;
Lond. and Edinb. Phil. Mag. vol. iii. p. 370.

Geological Society, 221

sandstone and greyish marl. In the sandstone the author noticed
no organic remains; but near the eastern boundary of the district he
observed, in a mass of clay mixed with sand, innumerable small
oysters ; and in a yellowish, calcareous freestone, corals, clypeas-
ters, pectens, and oysters. The best points for examining the
argillaceous beds are stated to be in the ravines between Lorca and
Velez Rubio, where they consist of about fifty feet of marl, con-
taining a few thin strata of reddish pulverulent sandstone, and
inclose shells belonging to the genera Pecten, Ostrea, Venus,
Tellina, Murex, Emarginula, &c. Upon the argillaceous strata
rests a bed of conglomerate in which the author found the long-
hinged oyster, so abundant in the newer formations of the South of
Spain. The inclined system occurs in the immediate vicinity of
Lorca, and consists in the lowest part of sandy loam and sandstone,
calcareous and quartzose freestone, and fine conglomerate ; and in
the upper part of foliaceous, indurated marl, gypseous marl, and
gypsum. No organic remains were noticed by the author. The
strata dip towards the north at an angle of 15 or 20 degrees, and
rest upon the highly-inclined beds of transition rocks.

Totana. This village is about twenty miles E.N.E. of Lorca,
and is situated in a prolongation of the highly-inclined gypseous
system of the latter place.

Alhama and Mula. In the immediate neighbourhood of Alhama
no tertiary strata occur, but to the north of the plain extending from
it to Murcia, is a hilly tract in which is situated Mula. The southern
part of this tract is composed of an immense deposit of earthy,
whitish -grey, argillaceous marl, containing numerous beds of gyp-
sum and brine springs, and the northern of a thick series of
sandstone and argillaceous beds which are slightly inclined towards
the south and dip under the former. In the alternating sandstone
and argillaceous beds, portions of the long-hinged oyster were
found. Beneath this series, in the neighbourhood of Mula, occur
beds of reddish sandy loam and sandstone, resting on highly inclined
strata of nummulitic limestone; and to the north of this ridge of lime-
stone is an horizontal deposit of the tertiary, shelly freestone before
described. Along the south-eastern border of the hilly district, the
gypseous formation is disturbed in the same manner as at Lorca
and Totana.

Cartagena. In the neighbourhood of this town the tertiary
strata are extensively developed, and constitute, apparently, the
whole of the great plain which ranges from Cartagena north-
wards to the Fuensanta ridge. On the southern extremity of the
plain the strata dip towards the north, and at the northern extre-
mity towards the south. The surface of the district consists of
clay, marl and sand, which the author conceives have been de-
rived from the decomposition of the tertiary strata. The beds from
the eastern termination of the Fuensanta ridge to the Segura, con-
sist of the calcareous sandstones and comminuted shelly limestone ;
and in the neighbourhood of Cartagena the same beds are well
displayed in numerous and extensive quarries.

222 Geological Society.

The author in conclusion states that M. Deshayes considers the
tertiary deposits of this portion of Murcia to belong to the second
and third epochs.

A memoir was afterwards read, " On the Geology of the Ber-
mudas," by Lieut. Nelson, of the Royal Engineers ; and communi-
cated by the President.

The author commences the memoir with a general description of
the form, structure, and meteorological phenomena of the Bermu-
das, and draws a minute comparison between the characters which
they present, and those assigned by Kotzebue to the Coral Islands
in the Pacific.

He says that the Bermudas consist of about one hundred and
fifty islets, lying within a space of fifteen miles by five, and situated
on the S.E. side of a zone of coral reefs, approximating in form to
an ellipsis, the major axis of which is twenty-five miles and the mi'
nor thirteen. The highest point is stated to be Sears Hill, 260 feet
above the level of the sea; and the undulating portions of the islands
are described as resembling sand-hills in shape, and chalk downs
in colour.

The whole group is composed of calcareous sand and limestone,
derived from comminuted shells and corals, and the different va-
rieties are associated without any definite order of position, the
harder limestones occasionally resting upon loose sand. The ar-
rangement of the beds is often domed-shaped, but in many instances
the strata are singularly waved.

The bottom of the basin within the zone of coral reefs is stated to
consist of corals, calcareous sand, and soft calcareous mud resem-
bling chalk, and considered by the author to have been derived
from the decomposition of Zoophytes.

Under the head of encroachments, he describes the banks of
detritus thrown up by the sea, and the progress which, under
certain circumstances, the loose sand makes in overwhelming tracts
previously fertile. He states that wherever the shrubs and creepers
have been destroyed, the sand has spread rapidly, but that it is inva-
riably stopped as soon as it arrives at a plantation or row of trees.

The shells found by the author in the sand as well as the lime-
stone, belong entirely to recent species, the most abundant being
the Venus Pennsylvanica, which in some of the islands constitutes
entire beds. The only vegetable remains which he observed were
casts of the root of a plant considered by the natives to belong to
the palmetto which now grows upon the island.

Caverns are stated to be very numerous, and their origin is as-
signed to the undermining action of the sea.

The memoir concludes with an account of the method by which
the author conceives coral islands and reefs are formed.

May 7.— A paper was first read, " On the Distribution of Organic
Remains in the Lias Series of Yorkshire, with a View to facilitate
its Identification by giving the Situation of its Fossils," by W. Wil-
liamson, jun., Esq. of Scarborough.

The part of the Yorkshire coast to which this paper immediately

Geological Society, 223

refers, extends from the Peak Hill near Robin Hood's Bay to the
village of Saltburn near Redcar. The lias presents the threefold
arrangement of alum-shale, marlstone, and lias marl or lower lias
rock.

The first of these deposits, the author says, consists of three di-
stinct divisions, viz. (a) soft, rubbly shale 130 feet thick, (b) hard
shale breaking into large lamellar blocks, 30 feet thick, and (c) soft
sandy shale from 15 to 20 feet thick. The upper part of the su-
perior bed of soft shale (a) is characterized by Ammonites striatulus,
A. communis, A.crassus, and Trigonia literata ; the middle portion,
from which alum is manufactured, by Ammonites Walcottii, A. he-
terophyllus, and Nautilus astacoides ; and the lowest by Ammonites
exaratus, A. elegans, Nucula ovum, and the remains of Saurians. The
hard shale (b) is distinguished by the presence of jet, Ammonites
elegans, Belemnites compressus, B tubularis, and Inoceramus dubius;
and the lower bed of soft shale (c) by the great abundance of Am-
monites annulatus.

The marlstone, or second division of the lias series, is characterized
by Ammonites Hatvkerensis, A. Clevelandicus, A. Stokesii, Belemnites
conicus, B. elongatus, Turbo undulatus, Dentalium giganteum, Iso-
cardia lineata, Cardium multicostatum, C. truncatum, Corbula car-
dioides, Amphidesma recurvum, Mya V-scripta, M. literata, Pla-
giostoma Iceviusculum, Pecten equivalvis, P. sublcevis, Avicula incequi'
valvis, A. cygnipes, Plicatula spinosa, Modiola scalprum, M. Hillana,
and Terebratula bidens, T. subrotunda, T. tetrahedra, and T. tri-
plicata.

The lower lias rock is distinguished by Ammonites planicosla, Pli-
catula spinosa, Hippopodium ponder osum, Lutraria ambigua, Pinna
folium, Gryphaa depressay G. Maccullochii, G. incurva, Pentacri-
nites Briar eus, and P, vulgaris.

In preparing these lists, the author says that he has omitted to
mention those fossils which he has not seen, or those which, from
their rarity, can be of little use in distinguishing the different sub-
divisions of the lias series ; and in conclusion, he states, that he has
found the fossils enumerated above, almost invariably in the beds to
which he has assigned them ; and he is of opinion that similar
sections may be drawn up on the same minute scale of the contents
of all the other strata, but that it remains for further investigation
to determine to what extent.

A paper was afterwards read, entitled, " Observations on the
Loamy Deposit called Loess in the Valley of the Rhine," by C.
Lyell, Esq. For. Sec. G.S.

In this paper Mr. Lyell details some observations made by him
in the summer of 1833, on the loess between Cologne and Heidel-
berg, and in several parts of Baden, Darmstadt, Wiirtemberg and
Nassau. Near Bonn large deposits of loess containing recent
shells rest on the gravel of the plain of the Rhine. The author
collected two hundred and seventeen entire shells, of which one
hundred and eighty-five individuals were of terrestrial species be-
longing to the genera Helix, Pupa, and Clausilia, and thirty-two of

224? Geological Society,

aquatic species of the genera Limnea, Paludina and Planorbis. This
large proportion of land shells is very general in the formation.
The author then made a collection of such shells as are now drifted
down by the Rhine and occasionally cast ashore by the waves, in
which case the shells for the most part retain their colour and are
perfectly distinguishable from fossils washed out of the loess. Out
of two hundred and seventy -three individuals thus procured, one
hundred and forty-seven were land shells and one hundred and
twenty-six aquatic. The author infers that if the waters of the
Rhine were now received into a lake, the sediment of such a lake
might contain more terrestrial than aquatic shells.

After some observations on the hollows and furrows in the gravel
of the Rhine which have been filled with loess, the author states
that the interior of the crater of the volcanic mountain called the
Roderberg is in great part filled up with pure loess, which was
pierced to the depth of 65 feet in digging a well in 1833. But
although this and other sections prove the posteriority of the loess
in general to the volcanic formations of the Eifel, Mr. Lyell ad-
mits that at Andernach there have been considerable falls of pumice,
scoriae and volcanic sand during the period of the formation of the
loess. In proof of this, the sections in the Kirchweg near Ander-
nach, are described.

The loess is then stated to be spread almost everywhere over the
tertiary and secondary strata around Mayence, Oppenheim, Alzey,
Flonheim, Eppelsheim and Worms. There is a section of loess
with shells, alternating several times with gravel, at the Manheim
gate of Heidelberg.

The loess between Heidelberg and Heilbronn appears to attain
the height of seven or eight hundred feet above the sea. In this
district, shells of the Succinea elongata alone are so abundant as to
exceed in number all the accompanying land shells. The author
then mentions the loess near Stuttgard and between Goppingen and
Boll in Wurtemberg. He found no traces of it in the course of a
tour by Heidenheim, Solenhofen, Nuremberg, Bayreuth, and the
cave district of Muggendorf, but he found it again between Bam-
berg and Wurtzberg in the valley of the Mayne. It was wanting
in the Spessart and the country around Aschaffenberg, but is abun-
dant near Frankfort and in several parts of Nassau. In the valley of
the Lahn near Limburg, it contains its usual shells and alternates
frequently with gravel.

From these facts and others mentioned in the paper, the author
deduces the following conclusions: —

First, That the loess is of the same mineral nature as the yellow
calcareous sediment with which the waters of the Rhine are now
commonly charged.

Secondly, The fossil shells contained in the loess are all of recent
species, consisting partly of land and partly of freshwater shells.

Thirdly, The number of individuals belonging to land species
usually predominates greatly over the aquatic, and this seems now
to be the case with the modern shells drifted down by the Rhine.

Geological Society. 225

Fourthly, Although the loess when pure appears unstratified, it
must have been formed gradually, as the shells contained in it are
numerous and almost all entire, and beds of shelly loess sometimes
alternate with strata of gravel or volcanic matter.

Fifthly, Some volcanic eruptions must have taken place during
and after the deposition of loess.

In conclusion, the author states that great changes must have oc-
curred in the physical geography of the basin of the Rhine since
some of the loess was deposited, and consequently at a comparatively
modern geological era, when the recent Testacea existed.

As the waters must have been at rest when the loamy sediment
was thrown down, we must suppose one or many temporary lakes
and ancient barriers which have since been removed. It is shown
that to assign the probable places of these would be very difficult,
and more data are required respecting the greatest height which the
loess attains.

May 21. — A paper was read, " On certain Trap Rocks in the
Counties of Salop, Montgomery, Radnor, Brecon, Caermarthen,
Hereford and Worcester; and the Effects produced by them upon
the stratified Deposits," by Roderick Impey Murchison, Esq.,
V.P.G.S. F.R.S. &c.

Having established an order of succession in the various sedimen-
tary formations between the carboniferous series and the older
grauwacke slates, the author proceeds in this memoir to explain
the nature of the trap rocks which rise to the surface in the region
under review. These rocks are described in the following order.

1st. Those which protrude in separate ridges through various
members of the grauwacke series between Lilleshall Hill, Salop, on
the north-east, and Llangadock, Caermarthenshire, on the south-
west.

2nd. The Malvern and Abberly Hills, including dykes which tra-
verse the old red sandstone.

3rd. Rocks penetrating the coal measures.

I. Shropshire and Montgomeryshire. — Lilleshall Hill consists
chiefly of compact felspar rock, having in parts a sienitic structure.
The Wrekin, which has been described by Mr. A. Aikin in the
Geological Transactions*, is of nearly similar composition. Lea and
other rocks near Wrockardine have the same base, but pass into
porphyry and clinkstone.

In Charlton Hill, porphyries and greenstones occur where they
had not been previously noticed.

These rocks mark parallel axes of different lengths on the north
bank of the Severn, ranging from north-east to south-west, and
piercing through beds of grauwacke, chiefly those of the third, or
Horderley and May Hillf formation, the sandstones of which, on
the sides of the Wrekin and Arcal, and at Charlton Hill, are con-
verted into quartz rocks at their points of contact with the trap.

The line of disturbance occasioned by the protrusion of the zone

* Geol. Trans., 1st Series, vol. i. p. 191.

+ See the "Table of the stratified Deposits,"&c.,in our last voUime,p. 370.

Third Series. Vol. 5. No. 27. Sept. 1834. 2 G

'226 Geological Society.

of Charlton Hill, is traced in certain trap rocks which appear in the
bed of the Severn, near Cound, extending thence to the south-west.

Caer Caradoc. — This remarkable ridge, formerly described by
Mr. A. Aikin*, is on a line of eruption parallel to that of the Wrekin.
It includes the hills of Lawley, Great and Little Caradoc, Helmeth,
Ragleath, &c, together with a large contrefort on its south-eastern
face. At Cardington and Hope Bowdler it consists of many varieties
of felspar rock, sienite and greenstone. The beautiful amygdaloid
with actynolite first pointed out by Dr. Townson, and supposed to
be peculiar to one spot, is shown to be of frequent occurrence in
several of these hills. The axis of elevation of this ridge has been
traced by the author to nearly six miles south-west of the limit
formerly assigned to it, the trap reappearing at Wartle Knoll,
Hopesay, Sibdon, Aston and Corston.

Numerous examples are adduced of the conversion of sandstone
into quartz rock where in contact with the eruptive rocks of these
hills, particularly on the south eastern flank of the Lawley, Little
Caradoc, and Cardington Hills, the strata of sandstone being
thrown off the flanks of the trap rock in vertical and dislocated
forms, in some of which the traces of bedding are with difficulty
observed. These conversions of sandstone on the sides of the Wrekin
and Caradoc Hills are supposed to have been caused by the action
of heat, accompanying the forcible intrusion of some of these trap
rocks. A large mass of impure limestone, somewhat indurated, and
containing many fossils of the Ludlow formation, has been heaved
into a vertical and detached position at Botville, on the north-
western face of Caer Caradoc.

Besides these dislocated masses, the author describes a portion of
the third formation (May Hill and Horderley), which rises from be-
neath the Wenlock shale, contains organic remains, and reposes on
the flanks of these trappean hills, as being in structure so analogous
to the unstratified rocks themselves, that he terms it '* Volcanic Sand-
stone" and conceives that it must have been formed during a period
of volcanic action, and that the materials of which it is composed
are the residue of ashes given off during submarine ejections. A
similar rock is found near the Wrekin.

Longmynd, Linley, Pontesford, and Haughmond Hills. — The
ancient grauwacke system of the Longmynd and Linley Hills, or
mineral axis of Shropshire t, is penetrated by a vast number of
points of eruptive trap, chiefly greenstones. Pontesford Hill, amid
varieties of greenstone, contains also a porphyry and a remarkable
amygdaloid. This zone is reproduced at intervals in Sharpstone
Hill, and has been observed by the author in Haughmond Hill,
four miles north-east of Shrewsbury, where it passes into a coarse
sienite. Vertical, veined, and indurated strata appear at different
points along these lines of eruption. Copper ores have been par-
tially worked on the western sides of the Longmynd, and at Nor-
bury. Quartz crystals and small portions of anthracite are found

* Geol. Trans., 1st Series, vol.i. p. 207-
: j, t See our last volume, p. 370.

Geological Society, 227

here and there, and at Lyds Hole are jaspidified red sandstones,
with abundant veins of carbonate oflime, &c., the whole being in a
state of extreme contortion and irregularity.

Shelve, Corndon, Sfc— The mining district of Shelve is an iso-
lated tract, separated from the Linley and Longmynd Hills by the
remarkable ridge of quartz rock, called the Stiper stones. It is
made up of parallel ridges of trap, and alternating depressions in
grauwacke. The trap rocks of this district are greenstones, por-
phyries, claystones, &c. These are separated by the author into
two classes ; the one, alternating conformably with the strata of the
third and fourth grauwacke formations, is supposed to be contem-
poraneous with them j the other is shown to be posterior to the
consolidation of the stratified deposits. In the contemporaneously
formed traps are several varieties, some of which, although aggre-
gates of compact felspar with a concretionary structure, contain
organic remains : others graduate into the class of volcanic sand-
stone. The first are best seen near Leigh Hall, the latter in the
Corndon flagstones, Mary Knoll dingle, &c, where they are largely
quarried.

The other class, or the intrusive trap, rises to the greatest heights
and to the largest masses in the Corndon, Stapely, Taudley, and
Roundton Hills, which form the chief axis of the district ; but there
are other linear eruptions, many of which are of extreme tenuity,
occasioning numerdus alternations of trap and grauwacke. The
trap rocks consist of greenstones, porphyritic greenstone, compact
felspar, concretionary felspar simple and porphyritic, amygda-
loids, &c.

Some remarkable parallel dykes are described running from north-
east to south-west between beds of grauwacke, shale, and calcareous
flag, which latter in some instances is converted near the prismatic
ends of these dykes, into cream-coloured porcellanite. In the
grauwacke adjacent to the trap are also many productive veins of
lead, which are respectively described at the Snailbach, Penally,
Bog, Gravel, Grit, and Roman Mines.

Besides these ores of lead, sulphate of barytes, sulphuret of iron,
and carbonate oflime are very abundant.

Stiper Stones. — This dentated and lofty ledge of quartz rock
belongs to sandstones of the fifth formation of the previous table*,
which have been altered by igneous action, and thrown up into their
present highly inclined and broken forms by the eruption of vol-
canic rock, lines of which are pointed out both on the western and
eastern faces of the ridge, and some of which it is presumed lie con-
cealed beneath it.

To the west and south of the above district small portions of trap
are noticed at Nantcribba, Montgomery, and at Heblands near
Bishop's Castle.

Breiddin Hills. — These hills are divisible into ridges running
from east-north-east to west-south-west, which, although parallel to

* See the Table.
2G2

228 Geological Society.

each other, are not parallel to those previously mentioned. The
eastern or chief of these is marked at one extremity by the Mid-
dleton and Moel y Golfa Hills, and at the other by those of Buil-
they and Bauseley. In this ridge are compact felspar rocks, slaty
porphyries, greenstone, and much concretionary rock, frequently of
very large size. These trap rocks burst through strata of grauwacke,
in some of which fossils of the Ludlow and Wenlock formations
have been found. The strata in contact are much hardened and
fractured, and contain many veins of carbonate of lime, and sul-
phate and carbonate of barytes, &c. &c.

The other chief ridge, or that on which Rodney's Pillar stands,
is composed in great part of coarse-grained columnar greenstone,
passing at its extremities into fine concretionary trap and clinkstone.
The Criggan, a third or minor ridge, included between these, ex-
hibits bosses of greenstone, with altered and silicified schists on
their sides.

A new locality of singularly spotted trap rock piercing through
an impure limestone full of shells, is noticed at the Cefn, between
the Moel y Golfa and Welch Pool.

The celebrated quarries of building-stone at Welch Pool expose
a broad dyke of columnar greenstone, passing in one part into con-
cretionary trap traversing strata of the same age, and producing
great changes in them in contact. The direction of this great dyke
is in the prolongation of the volcanic axis of the Breiddin Hills.
The last traces of these concretionary traps are observable in Powis
Castle Park.

Radnorshire. — The trap rocks in Radnorshire run in distinct
ridges from north-east to south-west : the most eastern are those near
Old Radnor ; the central or chief masses range from Llandegley
and Llandrindod to Builth ; a third and unimportant ridge occurs at
Baxter's Bank, five miles north-west of Llandrindod.

Old Radnor Group. — These trap rocks occupy two parallel ridges
comprising Stanner Rocks, Worsel Wood, and Hanter Hill on the
south-east, and Old Radnor Hill and its dependencies on the north-
west. These rocks are distinguishable from all others mentioned in
this memoir by the abundance of hypersthene, and exhibit many
passages from a coarse crystalline hypersthene rock to a fine-grained
greenstone. Unlike the hypersthene rocks in the Isle of Skye, their
base is for the most part of compact felspar, which passes into gra-
nular felspar, porphyry, &c.

In Old Radnor Hill, besides hypersthene rock and greenstone,
there are concretionary traps, bastard serpentine, &c. Towards
Harpton Court these latter rocks throw off a peculiar conglomerate,
having a base of felspar inclosing pebbles of quartz, which the author
supposes to have been formed by a mixture of volcanic matter with
submarine detritus.

The eruptive masses of trap tilt the strata of the Ludlow forma-
tion on the one side, and those of the Wenlock rocks on the other,
the most interesting phenomena being observable near Old Radnor
church and the quarries to the south of it, where the limestone has

Geological Society. 229

been cleared away from the abrupt faces and points of the intrusive
rock. Bands of imperfect serpentine are frequent between the trap
and the limestone. The latter, near the contact, is wholly unstratified,
crystalline, and hard, and only resumes its ordinary appearance at
a certain distance from the trap. The shale is altered into a hard
slaty substance. Coatings and nests of anthracite, together with
minute veins of copper ore and iron pyrites, appear near the junc-
tion, sometimes running from the trap into the altered deposits.

The author states that the phenomena are very analogous to
those of the Val di Fassa in the Tyrol.

On the north-eastern prolongation of this line of eruption is the
limestone of Nash Scar, which, although at its extremities (Wood-
side and Corten,) is demonstrably the equivalent of the Wenlock and
Dudley rocks, yet in this central part is a craggy mass of altered
and crystalline limestone, the changes in which are doubtless due
to the igneous influence which has shown itself on the same line
at Old Radnor.

Llandegley, Llandrindod , and Builth Group. — This large trap-
pean district having a length of nearly ten miles and a breadth of
five, is very similar in structure and physical features to that of
Shelve and Corndon in Shropshire, consisting of sharp ridges of trap
and deep trenched valleys in grauwacke, all running from north-
east to south-west. It is further analogous in presenting some evi-
dence of volcanic eruptions of date contemporaneous with the se-
dimentary deposits containing the Asaphus Buchii. Transverse
sections near Gelli and Buries, illustrate these phaenomena of re-
peated conformable alternation of concretionary felspar and other
rocks of igneous origin with stratified shelly deposits.

The most prominent elevations of trap consist of greenstones of
many varieties, felspar rock with quartz crystals, porphyries, both
amorphous and slaty, passing into porphyritic greenstone, amygda-
loids of various characters, concretionary rocks, claystone, &c.

The author points out, in some detail, the reckless folly which has
led people in this district to seek for coal by driving horizontal gal-
leries through the black schist on the sides of these eruptive ridges,
endeavours which they have been led to persevere in from the oc-
casional presence of small pieces of anthracite near the junctions.

The altered strata of grauwacke within and around the exterior
of these hills are of too frequent occurrence even to be named in
an abstract. Among a great number of cases, the author calls par-
ticular attention to the south-western termination of the great moun-
tain of Carneddau near Builth, where certain lower ridges of green-
scone, &c, cut through the shale and calcareous flag containing the
Asaphus Buchii, the beds of which are distorted, broken, indurated
and silicified, and in some instances changed to a milk white colour,
and to a brittle condition resembling some sorts of porcelain. Nu-
merous and large crystals of iron pyrites occur in these altered
beds, and as the mineral waters of the Park wells issue from them,
their origin is supposed to be due to the decomposition of the cry-
stallized pyrites. Hence the author infers that the mineral sources

230 Zoological Society.

of Builth, Blaen Eddw, Llandegley and Llandrindod, which seve-
rally issue from pyritized beds of grauwacke at points of contact
with intrusive rocks, are as much the result of volcanic action as the
mineral veins of Shelve in Shropshire.

Baxter's Bank contains a coarse-grained greenstone throwing
off black shale, which, in contact, is a silicified schist. Galleries in
search of coal have also been driven through these inclined strata.
A little spur of trap reappears at Caerfagie, one mile south-west of
Baxter's Bank.

[To be continued.]

ZOOLOGICAL SOCIETY.

May 13. — A Note was read from Mrs. Barnes, in which it was
stated that that lady had brought up from the nest two of the smallest
species of Jamaica Humming-birds. They were so tame, that at a call
they would fly to her, and perch upon her finger. Their food was sugar
and water. During the passage to England one of them was killed
by the cage in which they were kept being thrown down in a storm ;
its companion drooped immediately, and died shortly afterwards.

It was remarked that injury to the bird in consequence of such an
accident might be prevented by the introduction of a gauze-net screen
into the cage, at some little distance within the wires.

Specimens were exhibited of several Mammalia from India, which
had recently been presented to the Society by Lord Fitzroy Somer-
set. They were brought under the notice of the Meeting by Mr. Ben-
nett, who called particular attention to the skin of a Paradoxurus,
which he regarded as that of Par. prehensilis, Gray, a species hitherto
known only by a drawing of Dr. Hamilton's preserved in the East
India House*.

The general colour of the animal is a pale greyish brown, in which
longer black hairs are sparingly intermixed on the sides. On the
back of the head and neck, and along the middle line of the back,
these black hairs are almost the only ones that are visible. On the
loins they form three indistinct black bands, of which the lateral are
in some measure interrupted. The head is brownish, with the usual
grey mark both above and below the eyes, and there are some short
grey hairs between the eyes and across the forehead. The limbs are
brownish black, rather darker towards their upper part. The tail, at
its base, is of the same colour as the back, and rapidly becomes black j
its terminal fifth is yellowish white. The ears are rather large, and
sparingly covered with short brownish hairs.

Specimens were exhibited of three species of horned Pheasants, in-
cluding the Tragopan Temminckii, Gray. In illustration of the hi-
story of the latter bird, Mr. G. Bennett, Corr. Memb. Z.S., placed
upon the table drawings of specimens observed by him at Macao, and
showing the remarkable wattle in various degrees of development. He
also read a note on the subject.

In its contracted state the membrane has merely the appearance

♦ See Lond. and Edinh. Phil. Mag., vol. i. p. 399.

Zoological Society. 231

of a purple skin under the lower mandible ; and it is even sometimes
so much diminished in size as to be quite invisible. It becomes de-
veloped during the early spring months or pairing season of the year,
from January to March, when it is capable of being displayed or con-
tracted at the will of the bird. During excitement it is enlarged, falls
over the breast, and exhibits the most brilliant colours, principally of
a vivid purple, with bright red and green spots : the colours vary in
intensity according to the degree of excitement. When they are
most brilliant, or, in other words, when the excitement is great, the
purple horns are usually elevated. The living specimens seen by
Mr. G. Bennett were procured from the province of Yunnan, bor-
dering on Thibet. Mr. Beale, in whose aviary at Macao they were,
had not succeeded in obtaining females of this race. Its Chinese
name is Tu Xou Nieu.

Mr. G. Bennett also read a note on the habits of the King Penguin,
Aptenodytes Patachonica, Gmel., as observed by him on various occa-
sions when in high southern latitudes. He described particularly a
colony of these birds, which covers an extent of thirty or forty acres,
at the north end of Macquarrie Island, in the South Pacific Ocean.
The number of Penguins collected together in this spot is immense,
but it would be almost impossible to guess at it with any near ap-
proach to truth, as, during the whole of the day and night, 30,000 or
40,000 of them are continually landing, and an equal number going
to sea. They are arranged, when on shore, in as compact a manner
and in as regular ranks as a regiment of soldiers ; and are classed
with the greatest order, the young birds being in one situation, the
moulting birds in another, the sitting hens in a third, the clean birds
in a fourth, &c. ; and so strictly do birds in similar condition congre-
gate, that should a bird that is moulting intrude itself among those
which are clean, it is immediately ejected from among them.

The females hatch the eggs by keeping them close between their
thighs ; and, if approached during the time of incubation, move away,
carrying the eggs with them. At this time the male bird goes to sea
and collects food for the female, which becomes very fat. After the
young is hatched, both parents go to sea, and bring home food for
it ; it soon becomes so fat as scarcely to be able to walk, the old
birds getting very thin. They sit quite upright in their roosting-
places, and walk in the erect position until they arrive at the beach,
when they throw themselves on their breasts, in order to encounter
the very heavy sea met with at their landing-place.

Although the appearance of Penguins generally indicates the neigh-
bourhood of land, Mr. G. Bennett cited several instances of their
occurrence at a considerable distance from any known land.

The Secretary announced the recent addition to the Menagerie of
the Perdix sphenura, Gray } the Philippine Quail, Coturnix Sinensis,
Cuv. j and the Hemipodius Dussumieri, Temm.? : all presented to the
Society by John Russel Reeves, Esq., of Canton. He added, that a
second male specimen of the Reeves's Pheasant, Phasianus veneratus,
Temm., had also been sent to the Menagerie by John Reeves, Esq.
A pair of the middle tail-feathers of the last-named bird, measuring

232 Zoological Society.

upwards of five feet in length, and presented by Wm. Craggs, Esq.,
were exhibited.

Numerous specimens were exhibited from Mr. Cuming's collec-
tion, in illustration of a Paper by Mr. Broderip, entitled, " Descrip-
tions of several New Species of Calyptraidtf"

The following are the new species distributed and characterized in
this paper :

Subgenus Calyptr^ea : Cal. rudis, corrugata, varia (a very vari-
able species, allied to Cal. equestris, and taking almost every shape
which a Calyptrcea can assume. It differs in thickness according to
localities and circumstances), cepacea, and cornea.

Subgenus Calypeopsis, Less. Cal. radiata, imbricata, lignaria
(The majority of individuals of this species have their shells so de-
formed that they set description at defiance : the comparatively well-
formed shell occurs so rarely that it may be almost considered as the
exception to the rule. When in this last- mentioned state, the circum-
ference of the shell is an irregular, somewhat rounded oval, and it
rises into a shape somewhat resembling the back of Ancylus, with the
apex very sharp and inclining downwards. The shell in this shape is
generally less corrugated than it is in deformed individuals, though
some of those are comparatively smooth j but in both states the shell
is striated immediately under the apex, and is for the most part cor-
rugated on the other side of it.), tenuis, hispida, maculata, and serrata.

Syphopatella, Less. ? Cal. sordida, Unguis, Lichen, viamiUaris,
striata, and conica.

Subgenus Crepipatella, Less. Cal. foliacea (bears no remote
resemblance to the upper valve of some of the Chamce when viewed
from above), dorsata (the back of this shell is not unlike the upper
valve of some of the Terebratulee), dilatata, strigata (may possibly be
a variety of the last), Echinus (old specimens bear a great resemblance
to the figure of Crepidula fornicata in Sowerby's Genera of Shells,
No. 23, f. I.), Hystrix (approaching the last: but Mr. Broderip would
not be positive that they are not all varieties of Crepidula aculeala,
Lam.), and pallida.

Subgenus Crepidula, Less. Crep. unguiformis. Cal. Lessonii
(will remind the observer of the upper valves of some of the Chamce),
incurva, excavata (remarkable for the depth of the internal margin
before it reaches the septum ; that depth, however, being less than
in Crep. adunca, Sow.), arenata (approaches Crep. porcellana,) mar-
ginalis, and squama.

May 27. — A Letter was read, addressed to the Secretary by Sir
R. Ker Porter, Corr. Memb. Z. S., dated City of Caracas, April 7,
1 834. It related chiefly to a Monkey, and to some Tortoises, recently
presented to the Society by the writer.

The Monkey is described in detail. It is the Pithecia sagulata, the
jacketed Monkey or Simla sagulata of Dr. Traill. Sir R. Ker Porter
points out the several differences in colouring which exist between
this individual and the published description by the Baron Humboldt
of the Pithecia Chiropotes : these consist chiefly in the comparative
paleness of its back, and the greater darkness of the remainder of its

Zoological Society, 233

body and of its bushy beard. He adds that the animal drinks fre-
quently, always bending down on its hands, and putting its mouth
to the surface of the water, heedless apparently of wetting its beard,
and indifferent to the observations of lookers-on : he never saw it
take up water in the hollow of its hand, and carry it in this manner
to its mouth in order to drink. Its favourite fruit is the apple ; and
it does not refuse the pinion of a roasted chicken. Its voice is a
weak and chirping whistle, which becomes shrill and loud when the
animal is angry. It was obtained from the vicinity of the Orinoco,
not far distant from the Rio Negro, in the heart of Guiana. It is
known as the Mono Capuchino.

The Tortoises are referable to the Testudo carbonaria, Spix.
The Secretary announced that there had recently been added to the
Menagerie a white-crested Cockatoo, Plyctolophus crisiatus, Vieill. ;
and a pair of the blue Jay, Garrulus cristatus, Cuv.

He also stated that there had been acquired for the Menagerie a
Rhinoceros of the one-homed species of Continental India. It is said
to be about four years old. Its height at the loins, the highest part
of the back, is 4 feet 10-A- inches ; its length, from the root of the tail
to the tip of the nose, measured in a straight line, is 10 feet 6 inches j
its weight is about 26 cwt.

A specimen was exhibited of the young of the Sandwich Island
Goose, Bernicla Sandvicensis, Vig., which was hatched at Knowsley.
It was accompanied by the following note from the President, Lord
Stanley.

" Through the kindness of John Reeves, Esq., I received at
Knowsley a pair of these birds on the 15th of February, 1834.
They did not at first, when turned out on the pond among the other
water-fowl, appear to take much notice of each other ; but some
workmen being at the time employed about the pond, one of the
birds (I think, from recollection, it was the male,) seemed to have
formed some sort of attachment to one of the men working. When-
ever he was present the goose was always near to him, and whenever
absent at his dinner, or when otherwise employed, the bird appeared
restless, and gave vent to its solicitude by frequent cries, which as
well as the anxiety, always ceased with the reappearance of the
workman.

* The man having frequently occasion to pass through a door, which
was obliged to be kept open, it was feared that the attachment of the
animal might lead to its following its friend, and that on its exit, it
might fall in with and be worried or stolen by vermin, and in conse-
quence the pair of geese were confined in one of the divisions adja-
cent to, but divided from, the pond, on February 26.

" Within this small inclosure, in the sheltered half of it, in one
corner, stood a small hutch, in which the female on the 5th of March
laid her first egg. Till within a few days of that period no alteration
took place in their manners, but it then became obvious that the male
was jealous of intruders, and would run at and seize them by the
trowsers, giving pretty sharp blows with his wings ; but this always
ceased if he observed that the female was at some distance, when
Third Series. Vol. 5. No, 27. Sept. 1834. 2 H

234 Zoological Society.

he would instantly rejoin her : his return to the female was always
accompanied by great hurry and clamour, and much gesticulation up
and down of his head, but not of the wings. Three other eggs followed
on the 7th, 9th, and 1 1 th of March. The eggs were white, and very
large in proportion to the size of the bird, being, I should imagine,
(for, having no proper scales at hand, I did not weigh or subtract any
of them, hoping that more might be laid,) fully equal to those of the
Swan Goose or Anas cygnoides. The goose also surprised us by the
rapidity of her operations, for we were hardly aware of the fourth egg
having been laid that morning, when it was evident that she had be-
gun to sit. During the whole period of incubation there could not
be a more attentive nurse, and indeed she could not well help it, for
the male, if she seemed inclined to stay out longer than he thought
right, appeared, by his motions, to be bent on driving her back, nor
was he satisfied till he had accomplished his object, when he again
resumed his usual position, with his body half in half out of the
hutch and his head towards the female ; but if any person crossed the
yard of the division, he would immediately hurry after the intruder,
though, if he found there was no intention of molesting the nursery,
he seemed generally satisfied, and did not like to quit the sheltered
part ot the division. At nighi he constantly made room for himself
by the female, the result of which was unfortunate towards the pro-
geny.

" On the 12th of April the eggs began to chip, and on the 13th
two goslings were excluded ; but it was found that the mother had
pushed from under her the other two eggs, which were consequently
taken away and put under a hen, though, as one was very nearly
cold, little hopes of any success with that were entertained, and it was
in fact never hatched, but probably died in consequence of the re-
moval by the goose at an important moment. On the morning of the
14th it was ascertained that she or the male, who always now sat
close beside her in the box, had killed one of the two she had at first
hatched, for it was found dead and perfectly flat. The fourth eggf
which was put under the hen, was assisted out of the shell, and ap-
peared weakly from the first, and as its mother had lost one, we put
it to her, in hopes it would do better than with its nurse. She took
to it at first very well ; but subsequently, both the parents beating it,
it was returned to, and well cared for, apparently, by its nurse, but
died on the 20th, having received some injury in one eye, either from
the old ones, or perhaps from the hen scratching, and thereby hitting
it. The remaining gosling is doing very well, and appears strong
and lively, and the parents are extremely attentive to it j and I have
little doubt but these birds may easily be established, (with a little
care and attention,) and form an interesting addition to the stock of
British domesticated fowls.

" In its general appearance, and its Quaker -like simplicity of plum-
age, it seems to approximate most to the family of the Bernacles -, but
it appears to have almost as little (if as much) partiality for the water
as the Cereopsis."

The bird in question was named by Mr. Vigors at the Meeting of

Zoological Society. 235

the Society on June 1 1 , 1833. (Lond. and Edinb. Phil. Mug., vol. iii.
p. 293.) It may be characterized as follows :

Bernicla Sandvicensis. Bern, brunneo-nigrescens, subtHs mar-
ginibusque plumarum pallidioribus ; collo albescenti ; guld, facie,
capite superne, linedque longitudinali nuchali nigris ; crisso albo.

Long. tot. 24 uric. ; rostri, rictus, l-f j alee, 13i; caudce, 5; tarsi, 2-g-.

Hab. in insulis Sandvicensibus, et in Owhyhee.

Mr. Owen read a Paper " On the young of the Ornithorhynchus
paradoxus, Blum." It was illustrated by drawings of the young ani-
mal and of various details of its structure, both external and internal,
derived chiefly from the examination of the individual recently pre-
sented to the Society by Dr. Weatherhead : this individual was ex-
hibited, as was also a smaller specimen, forming part of Dr. Weather-
head's collection.

The circumstances which first attract attention in these singular
objects are the total absence of hair j the soft and flexible condition
of the mandibles j and the shortness of these parts in proportion to
their breadth as compared with the adult. The tongue, which in
the adult is lodged far back in the mouth, advances 1n the young ani-
mal close to the end of the lower mandible, and its breadth is only
one line less in an individual four inches in length than it is in fully
grown animals ; a disproportionate development which is plainly in-
dicative of the importance of the organ to the young Ornithorhynchus
both in receiving and swallowing its food.

On the middle line of the upper mandible, and a little anterior to
the nostrils, there is a minute fleshy eminence lodged in a slight de-
pression. In the smaller specimen this is surrounded by a discon-
tinuous margin of the epidermis, with which substance, therefore, —
and, probably, from its having been shed, of a thickened or horny con-
sistence,— the caruncle had been covered. It is a structure of which
the upper mandible of the adult presents no trace, and Mr. Owen re-
gards it as analogous to the foetal peculiarity of the horny knob on the
upper mandible of the Bird. He does not, however, conceive that
this remarkable example of the affinity of Ornithorhynchus to the fea-
thered class is necessarily indicative of its having been applied, under
the same circumstances, to overcome a resistance of precisely the
same character as that for which it is designed in the young bird,
since all the known history of the ovum of Ornithorhynchus points
strongly to its ovoviviparous development.

The situation of the eyes is indicated by the convergence of a few
wrinkles to one point j but the integument is continuous, and com-
pletely shrouds the eyeball. In the absence of vision in the young
animal, strong evidence is afforded of its being confined to the nest,
there to receive its nourishment from its dam j and this deduction is
corroborated by the cartilaginous condition of the bones of the ex-
tremities, and by the general form of the body : the head and tail are
closely approximated on the ventral aspect, requiring force to pull the
body into a straight line -, and the relative quantity of integument on
the back and belly shows that the position necessary for progressive
motion is unnatural at this stage of growth.

Mr. Owen describes other external appearances of the young Orrri-

2 H 2

236 Entomological Society.

ihorhynchus, and then enters at considerable length into its anatomy.
The stomach is nearly as large in an individual four inches in length
as in the adult animal. In this specimen it was found filled with
coagulated milk, and no trace was visible, on the most careful exa-
mination, of worms or bread, on which, up to the time of his dis-
covery of the mammary secretion, Lieut, the Hon. Lauderdale Maule
had believed that this individual had been sustained. A portion of
this coagulated substance was diluted with water, and examined un-
der a high magnifying power in comparison with a portion of cow's
milk coagulated by spirit, and similarly diluted. The ultimate glo-
bules of the Ornithorhynchus' s milk were most distinctly perceptible,
detaching themselves from the small coherent masses to form new
groups : the corresponding globules of the cow's milk were of larger
size. Minute transparent globules of oil were intermixed with the
milk globules of the Ornithorhynchus. A drop of water being added
to a little mucus, it instantly became opake j and its minutest divi-
sions, under the microscope, were into transparent angular flakes, en-
tirely different from the regularly formed granules of the milk of the
Ornithorhynchus.

In passing in review the several viscera of the young Ornithorhyn-
chus, Mr. Owen observed on various physiological deductions which
might be drawn from them, and on the differences and resemblances
borne by them to the same organs in the ordinary viviparous Mam-
malia and in the Marsupiata*.

ENTOMOLOGICAL SOCIETYf.

June 2.— Numerous donations of books and insects were an-
nounced. A prospectus of Prize Essays, on the subject of noxious
insects, and remedies for their destruction, proposed by the Society,
was read, offering the sum of five guineas annually for the best
essay. The subject of that for the present year to be the Turnep-fly .

Papers were read upon the Sphinx ephemceriformis, by J. F.
Stephens, Esq. ; Descriptions of various larvae of Coleoptera, by
Mr. G. R. Waterhouse j Upon the habits of Odynerus Antilope, by
Mr. Westwood ; Descriptions of the Irish Species of Thysanura, by
Mr. Templeton. Mr. Spence alluded to the annoyance caused to
the inhabitants of Brighton and some parts of London by the
swarms of a minute ant, which had infested houses, occasionally to
such a degree that the inhabitants were compelled to quit them.

July 7. — A report was read of the purchases of insects made at
the sale of the late Mr. Haworth's collections.

Papers were read upon the British species of Dromius, by C. C.
Babington, Esq., M.A.; Upon a new British genus "of Neuroptera
and family Hemerobiidce, by J. O. Westwood, F.L.S. ; Description
of a new genus of Curculionidce , from St. Helena, by M. Chevrolat
of Paris; Upon the British genera Acentria, Acentropus, and Zancle,
by Mr. Westwood j and the conclusion of Mr. Templeton's Thy-
sanura Hibernica.

* Other notices relative to the Monolrcmata and their affinities will be
found referred to in our last Number, p. 147.
t Continued from vol. iv. p. 385.

Intelligence and Miscellaneous Articles, 237

A Committee was appointed to investigate the ravages of the
Cane-fly of Grenada, with a view to the suggestion of the most effi-
cacious remedies against its attacks.

Aug. 4.— Lieut.-Col. W. H. Sykes, F.R.S., in the chair. The
report of the Committee appointed at the last meeting was read,
containing a variety of suggestions which were stated to have been
communicated to the Agricultural Society of Grenada. A curious
wasp's-nest built in the folds of a piece of paper, was exhibited by
Mr. Ingpen. Memoirs were read upon some new species of Ants
from the East Indies, with observations upon their habits, by Lieut.-
Col. Sykes; Description of a beautiful nondescript Lamia from
Sierra Leone, by Mr. Westwood.

XXXIV. Intelligence and Miscellatieous Articles,

m. breithaupt's mineralogy.

SINCE the insertion of the notice from Professor Hausman in
the 26th Number of this Journal, our attention has been drawn
to the recent work of another mineralogical writer, Mr. Breithaupt,
by two specimens, named by him peganit and pegmatit. We do
not perceive upon what principle he has considered these to be new
species, as they appear to us only varieties of the wavellite of Fran-
kenberg. His kupferindig, we recollect, did not present any very
definite specific characters to us ; and if his other supposed new
species are not better established than these, we fear that his many
new names will rather embarrass than assist mineralogy, and that his
discoveries will belong to a class which, we believe, is denoted in
his own language by a term we cannot well translate, but which
refers their value to the number of sacks of toind they may be
worth.

OBSERVATIONS ON THE TEMPERATURE OF ARTESIAN WELLS
IN DEGREES OF THE CENTIGRADE THERMOMETER, THE
DEPTHS BEING EXPRESSED IN METRES.

In the Neighbourhood of Vienna.

Depth. Temperature.

73-96 1375

34-14 11-6

34-14 116

1896 11-25

Mean temperature of the surface .... 10-25.
Hence the temperature increases at the rate of 1° centigrade in
20 32 metres.

Rochelle.

123-16 1812

Mean temperature of surface 1 1-87

Or the temperature increases at the rate of 1° centigrade in 19-71
metres.

Epinay.

67 14-

54 13*3

12 11*

238 Intelligence and Miscellaneous Articles,

These observations give an increase of 1° centigrade in descend-
ing through 18*32 metres.

Kupffer's observations in the mine of Bogoslowsk in the Ural,
give an increase of 1° centigrade in descending through 1984
metres. — Poggendorff 's Annalen, v. 32.

ON THE PHYSICAL AND THERAPEUTIC PROPERTIES OF CHRO-
MATE OF POTASH. BY M. JACOBSON.

Neutral chromate of potash may be exposed to a very high tem-
perature without being decomposed, unless charcoal be added to it,
which renders it incandescent. Hemp, cotton, linen, or cloth, im-
pregnated with this salt become very combustible, and burn with
strong and lively incandescence, and with considerable disengage-
ment of light and heat. The oxides of chromium and its different
salts possess the same property. The author has employed this
property of chromate of potash for the preparation of moxas.
Those which he made use of were made with blotting-paper soaked
in a solution made with one part of this salt and 16 parts of water:
the author proposes to make matches by immersing cotton in this
solution. An important property of this salt is its great solubility
in water, and its power of preserving vegetable and animal matter
from putrefaction ; it also removes the disagreeable smell from
putrid substances.

The bichromate is especially suited for preservation and disinfec-
tion, the solution containing about 1*250 of its weight of the salt.
Animal substances, with the exception of the nervous parts, are
not at all altered by this solution. With respect to the therapeutic
properties of chromate of potash, M. Jacobson employs it externally
as a resolvent, and when concentrated, as a caustic. Internally,
taken in doses of 1 or 2 grains, it is emetic, — Journal de Chimie
Medicate, Fevrier 1834.

DISCOVERY OF CHRENIC AND APOCHRENIC ACIDS IN THE MI-
NERAL WATERS OF PORTA. BY M. BERZELIUS.

The waters of Porta have acquired great celebrity on account of
their medicinal properties. The water is abundant, and bubbles of
gas, which consist of 6 volumes of azote and 1 volume of carbonic
acid, constantly rise from the bottom of the spring : the temperature
of the water is invariably about 45° Fahr. The colour of the water
is yellowish, and caused by an organized substance which it is dif-
ficult to isolate; it is composed of oxygen, hydrogen, azote and
carbon. It possesses acid properties, and when concentrated has a
sour taste : it is a mixtureof two acids*, one of which, occurring in the
greatest quantity, Berzelius calls chrenic acid, and the other apochrenic
acid, because it is formed from the first by the influence of oxygen
gas, &c. These acids are weak ; they nevertheless decompose the
acetates if the mixture is evaporated. Chrenic acid does not
crystallize : the solution concentrated to the consistence of a syrup
is almost colourless. When dried in vacuo it splits in all directions,
and has a false appearance of being crystallized ; its taste is then
distinctly acid and astringent. The watery solution has only an

Intelligence and Miscellaneous Articles. 239

astringent taste ; it is soluble in absolute alcohol, and but slightly
so in alcohol of density 0*85. The chrenates of the alkaline earths
are but slightly soluble in water, and they form insoluble sub-
salts. The greater part of other chrenates are insoluble except
the protochrenate of iron, which is very soluble.

Apochrenic acid is but slightly soluble in water, to which it gives
a brownish colour. The apochrenates resemble the chrenates
strongly, but they are brown or black, insoluble in alcohol, and
combine with hydrate of alumina by digestion, forming a colourless
solution. By this method they are easily separated from the chre-
nates.

These two acids are found in several chalybeate waters in Swe-
den, even when the waters are colourless. They may be separated
from the ochre which these waters deposit by boiling it with hydrate
of potash. The alkali being afterwards saturated with acetic acid,
the apochrenic acid is to be precipitated by acetate of lead as long
as a brown precipitate is formed, or a greenish one, which becomes
brown. The liquor afterwards neutralized by an alkaline carbonate
precipitates chrenate of copper in greenish white flocks, the quan-
tity of which is increased by adding more acetate of copper. The
copper is afterwards separated from the acid by means of sulphu-
retted hydrogen. Even ochry iron ore contains these acids.

The waters of Porta contain these two acids in the states of
the chrenates of soda and ammonia. In 100,000 parts of the water
there were found,

Chloride of potassium 0 3398

■ sodium 0-7937

Chrenate of soda 0-6413

Chrenate and carbonate of ammonia .. 08608

Bicarbonate of lime 9*0578

magnesia 1*9103

manganese 0*0307

iron 66109

Phosphate of alumina 001 10

Silica 3-8960

Chrenic and apochrenic acids 5*2515

29-4-038
Berzelius considers the azote disengaged from the water, and the
ammonia which saturates the chrenic acid, as the product of the
spontaneous decomposition of the two organic acids ; and he attri-
butes the acids to the putrefaction of vegetable substances on the
surface of the earth, in the extensive marshy forests which surround
the spring. — Journal de Chimie Medicate, Arril 1834.

SCIENTIFIC BOOKS.
In the Press.
A Guide to Geology j explaining the Elementary Facts and In-
ferences of that Science, with condensed Descriptions of the prin-
cipal Stratified and Unstratified Rocks, Tables, Plates, &c. By
Professor Phillips.

D

a

1

PEJ

London. — July 1—3. Fine. 4. Slight haze : very
hot. 5. Very fine : heavy rain at night. 6. Thun-
der and lightning with heavy rain. 7. Cloudy :
very fine : showers. 8 — 10. Cloudy and fine.
11. Very hot. 12. Clear and hot. 13—16. Very
hot. 17. Cloudless and excessively hot: ther-
mometer 94° in shade.) and 130° in sun's rays.
18. Hot and dry E. wind : at noon rain from S.W. :
thunder at night, with very heavy rain, falling to
the depth of more than an inch. 19. Heavy
rain. 20. Cloudy : showery : heary rain at night.
21. Showery. 22. Cloudy. 23. Foggy: fine.
24, 25. Very fine. 26, 27. Cloudy : rain at night.

28. Overcast : thunder and lightning, with rain at
night. 29. Sultry, with showers : thunder and heavy
rain at night. 30. Heavy rain : sultry : clear and
fine. 31. Heavy rain : foggy. More rain fell
in this month than in the five preceding taken
together.

Boston.— July 1 . Cloudy : rain p.m. 2, 3. Cloud}'.
4, 5. Fine. 6. Cloudy: rain early a.m. and p.m.
7. Cloudy. 8. Rain : rain early a.m. 9. Cloudy :
rain p.m. 10. Fine : rain a.m. 11—13. Fine.
14. Cloudy. 15. Fine. 16. Cloudy. . 17. Fine.
18. Stormy: rain p.m. 19. Cloudy: thunder and
lightning a.m. : rain p.m. 20. Cloudv : rain p.m.
21. Fine. 22. Cloudy. 23. Fine. '24. Cloudv.
25, 26. Fine. 27. Rain. 28. Cloudy

29. Fine : rain with thunder and lightning early
a.m. 30. Cloudy. 31. Fine.

.5

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THE

LONDON and EDINBURGH

PHILOSOPHICAL MAGAZINE

AND

JOURNAL OF SCIENCE.

[THIRD SERIES.]

OCTOBER 1834.

XXXV. A Method of determining the Number of Signals
which can be made by the Modern Telegraphs. By Charles
Blackburn, Esq., A.B.

To the Editors of the Philosophical Magazine and Journal.

Gentlemen,
A LTHOUGH the French telegraph or semaphore has
■"■ been in use for a considerable period, I am not aware
that any general rule for determining the number of signals
that can be made by these instruments has been given to the
public. The following investigation, therefore, may not be
unacceptable to such of your readers as are interested in that
mode of communication. Its object is to furnish a rule for
determining the number of distinct signals which can be made
by any semaphore, whatever be the number of arms or indi-
cators, or whatever be the number of positions of each arm.

In the Cyclopaedia of Rees, the number of signals which
the semaphores of the line of communication between Paris
and Landau were capable of making, is stated to be 823,54-3,
which is no less than 1,274,608 fewer than the real number,
an error not arising from the press, but from the principle of
computation. The following method, besides giving the true
number of signals, has the advantage of being reducible to an
expression of remarkable simplicity.

Problem. — To find the number of signals which can be
made by any semaphore having any given number of arms,
and each arm taking any given number of positions.

Third Series. Vol. 5. No. 28. Oct. 1834. 2 I

242 Mr. Blackburn on the Modem Telegraphs.

Let AB be an upright pole or staff, carrying any number
of arms FC, DG, HE, &c., moveable in a
vertical plane about the centres F, D, E, &c, ^ ^>

and capable of being placed in any number fb^c

of positions. This will represent the modern
telegraph or semaphore.

Let the number of centres F, D, E, &c.
be denoted by c, and the number of positions
of each arm by p. Then, since the number
of signals that can be made by one arm must
be equal to the number of positions of that
arm, the number of signals which can be
made with one arm = p9 and the number of
signals on the whole, using one arm at a
time, will be cp.

Again, since each of the signals which can
be made by any one arm, can be repeated with each of the
signals of any other arm, it follows that the number which
can be made by any two arms together = p%. And since
the number of combinations in c things, taken two and two

together, = ° \ C~ , it follows that the whole number of sig-

EI

PB
B

1 .2
nals, using two arms at once, =

c.c—l
1 .2

In like manner it may be shown that the number of signals

c . c-~— 1 . c mmm 2
which can be made using three arms at once = ^— — 5— — p3;

and that when all the arms are used at once, the number will

be

c.c—] .c-2

c-(c-l)

pc9 the index of p being al-
1.2.3 c

ways = number of arms used at once. The whole number of

signals, therefore, which the telegraph is capable of making

will be cp~^

. c.c—l

1 .2

c.c—l ,c — 2

J

2. J
&c.

+

c.c-

+ &c.
c— 2 c— (c

1.2.3

But if the binomial 1 +p be raised to the cth power, it will
be found to coincide exactly with the sum of the preceding

Mr. Blackburn on the Modem Telegraphs. 243

terms, with the exception of unity, by which it exceeds it.
The expression (l+p)c— 1, therefore, will accurately repre-
sent the whole number of signals.

Example. — In the Admiralty semaphore, the number of
centres or arms = 2, and the number of positions of each
arm = 6. Hence, by the theorem, the number of signals
will be (6 + l)2-l = 72-l = 48.

Example 2. — If the number of centres be three, as in the
preceding sketch, and the number of positions of each arm be
six, the number of signals will be (6 4- 1 )3— 1 = 73— 1 = 342.

Example 3. — In the year 1796, a line of telegraphs was
established between Paris and Landau, each of which had
seven arms, and each arm seven positions. It is required to
find the number of signals.

By the theorem, the signals m (7+1)7— 1 = 87— 1 =
2,097,151.

Corollary. — From the preceding investigation it appears
that, for any semaphore having c centres, and each arm p posi-
tions, the number of signals which can be made, using one
arm at once, will be represented by the second term of the bi-
nomial 1 +p raised to the cth power ; the number of signals
using two arms at once, by the third term of the same quan-
tity, &c; and the number of signals, using all the arms at once,
by the (c+l)th term.

Thus, in the Admiralty semaphore,
The signals using one arm at once = cp = 2x6=12

c c — 1
The signals using two arms at once = ff9= 1 x 69 = 36

Total number of signals, as before, = 48

In the Paris semaphore before mentioned, the signals using

one arm at once = cp = 7x7 = 49

two arms at once = ° \C~X p* = 21x49 = 1029

1.2 '

three arms at once = c-L£IzLl£Z^ ps m 35x343 = 12005

1.2 .0

four arms = c' c~l -g-~2--g-3 p< — 35x2401 = 84035

1.2.3.4 *

five arms ... « c'c~l 'C~2'C~3 ,c74 P> = 21 X 16807=352947

1 . x, . o . 4 . o *

c.c — l.c — 2.c — 3.c — 4.c — 5 « „ .,«.««* #»<*»»**
six arms = ^ g 3 ^ ^ g—p6 = 7x 117649=823543

scven=r.7\'72'T3'T4,T5;76^7==lx823543=823543

Total number of signals, as before, = 2,097,151
2 12

24-4" Mr. Carter's Remarks on Mr. Beke's Papers

The preceding investigation supposes one arm only on the
same centre, as in the modern semaphores; but as they may
be made with several arms on the same centre, it may be
proper on some future occasion to give the method of find-
ing the signals for such as have any given number of arms on
each centre, any number of centres, and any number of posi-
tions of each arm ; an investigation a little more complicated
than the preceding, but, like it, capable of reduction to an ex-
pression of great simplicity.

If, in any semaphore, instead of one arm on each centre, we
suppose as many arms on each centre as each arm has posi-
tions, the number of signals will be 2oc— 1.

Thus, if the Admiralty semaphore had six arms on each
centre instead of one, the number of signals would be 22x6— 1
= 4095 instead of 48 as at present.

It is indifferent in the application of the preceding theorem
in what order the centres are placed, but they should be in
the same vertical plane, and the plane perpendicular to the
spectator's line of vision.
Kensington-square, June 3, 1834.

XXXVI. Remarks on Mr. Beke's Papers on the Gopher-
wood, and the former Extension of the Persian Gulf. By
W. G. Carter, Esq.

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

TN Mr. Beke's observations in your April Number, on my
* paper in that for March, that gentleman represents me as
stating, that society previously to the Deluge " existed in a
state of infancy as regards its culture and knowledge," and
" that he apprehends the evidence we possess on the subject
ought to lead us to a very different conclusion." Mr. Beke
has here mistaken my meaning. I have not expressed any
opinion respecting the general culture and knowledge of
mankind at that period. My remark was confined to their
navigation only. Of all persons, Noah and his family were
the least likely to have been ignorant of any art in the build-
ing of vessels and boats which was possessed by the antedi-
luvian world. Whatever knowledge they had of the subject,
we may infer that they conveyed to their posterity. Yet have
we no reason to suppose, from the history of any country, that
the arts of ship-building and navigation had made any consi-
derable progress for many ages after the Flood. How, indeed,
were they to have been acquired? Navigation is cultivated
by an early, very much by any people, in seeking those sup-

on the Gopher-wood and the Persian Gulf I 245

plies which the country on their side of the ocean does not
afford them, or in emigration. But the nine generations of
mankind from Adam to Noah could not have so inconveniently
crowded the land they dwelt in, as to set themselves to invent
the arts and seek out means for the relief of an overburdened
country. Some indeed, without the slightest warrant from
the history, neglecting the only criteria we have in the families
of Noah who had but three sons, and Shem who had but five,
Ham four, and Japheth seven, and adopting a notion which
would make the wives of the antediluvian patriarchs mothers
of from two to four hundred children each, have filled the
whole earth with a swarming population *. But taking the
Mosaic history in its common-sense acceptation, mankind was
surely then in a state in which " boats and ships (and the use
of pitch to cover them) could be very little known."

Mr. Beke appeals to the cognate dialects in support of
kopher having the meaning of pitch; but unless we are to
suppose this manufactured product of a tree was then in use,
and obtained a name before the tree whence it was taken, the
analogy should have been sought for in the tree itself. No
word will, I believe, be found for the pine or fir in any of
them (and in Arabic there are several) having any resem-
blance to kopher, which, without the slightest change of let-
ters, is thus made to express both pitch and a tree in the
same sentence, and throughout the Hebrew Scriptures is in
no other instance employed to signify either.

My remark that the word expressing atonement and mercy-
seat were forms of the same word kopher, and that if, as in
Gen. vi. 14., it expressed pitch, some other word would pro-
bably have been chosen for those revered objects, with the like
import of a covering, Mr. Beke understands to convey, that
every root must in every case have attached to it its secondary
meaning. Why so ? Are a covering, a mercy-seat, and an
atonement convertible terms? I still think, in a religious
ceconomy like that of Moses, in which any association, though
often through a very remote idea, with things common, was
anxiously excluded, and all the aids, as well of the imagina-
tion as of the judgement, were obtained to secure the profound

* Adam seems to have had sons and daughters after Abel, Cain, and
Seth (Gen. v. 4.), and all the patriarchs before Noah are said to have had
daughters. His are not alluded to. He seems, then, to have had none,
and as we know he had but one wife, he offers the best criterion. If
at each generation the population doubled, that is, if each pair left four
children, at the Flood it was under six thousand ; if it quadrupled, it was
under three millions to people Asia. Whiston, irt the way noticed above,
makes it 549 thousand millions ! (Theory of the Earth, b. iii. ch. 3.)

24-6 Mr. Carter's Remarks on Mr. Beke's Papers

reverence of the worshipers, some other word would have
been selected to express the atonement and mercy-seat, than
one to which the people must have been daily familiar in the
sense of pitch and a sliming over of pitch, from their tradi-
tionary or other history, and that this is one reason, though
not " the principal," for inferring that the word, nowhere else
used in that sense, is not so used here*.

To the country near Babylon being the spot of Noah's ante-
diluvian residence, Mr. Beke objects, as being founded on
mere tradition, mentions the place where the ark rested to be
Armenia or the North of Mesopotamia, a statement which can
scarcely be considered as founded on anything better, — then,
taking that as a fact, observes," The most philosophical course
is to assume that in the neighbourhood where the ark rested
there also it was built." Why, in the unequalled atmospheric
disturbances which the narrative of the Deluge bespeaks, the
ark should be thus immoveable is not very manifest. I as-
sume it was just as likely to be found at length in any other
spot, as in the one where such uncertain agency began to act
upon it.

It being universally allowed that Babylon (Babel in the
original) was in the neighbourhood of Hillah, and the Jewish
church having furnished us with the same name for both the city
and the country of the tower-builders and those of Nimrod f ,
the natural inference is that they are identical. Mr, Beke, con-
sidering that, at this period, the Persian Gulf occupied, or the
waters of the rivers desolated, this part, denies their identity,
the only reason appearing to be, that at the dispersion in
Peleg's days the builders are said to have " left off to build
the city." But if we consider that Nimrod was but the third
from Noah, and Peleg the fifth, the spots, which in time
grew into cities, become but inclosed lands or small villages,
and the dominion mere patriarchal rule. On that event hap-
pening, enough of the habitations of such a period might have
been ready for those who probably remained with Nimrod J,

* The very word said to signify pitch is used to designate the Messiah:
" Deliver him, &c. : I have found (kopher) a ransom."— Job xxxiii. 24.

f See Gen. x. 9. 10. and xi. 2.9.; 1 Chron. xxxvi. 7. ; and Dan. i. 2.
By comparing which we find that Babel as well as the Babylon of Nebu-
chadnezzar was in the land of Shinar.

X Is. xxiii. 13. seems distinctly to identify Nimrod' s Babel and Babylon:
rt The Assyrian founded it (Chaldea or Babylon) for them that dwell in the
wilderness." That Nimrod was the patriarchal chief of Assyria is deter-
mined by Micah v. 6., where Assyria is expressly called " the land of Nim-
rod." It is surely manifest that it could be his land in no other sense than
that he first settled it. Thus the Assyrian Nimrod founded Babel, formed
into a social community the remnant of the people scattered and broken

on the Gopher-wood and the Persian Gulf. 247

and which must have been provided for the tower-builders,
without compelling us to infer that the earth's then scanty
inhabitants had given a name to two different places, after-
wards, moreover, extended to a third, and all in the same land,
signifying " confusion," especially assigned because at one of
them " the Lord did confound the language of all the earth."
It is for this multiplication that " the warrant" seems re-
quired.

Mr. Beke, however, in his paper on the former extension
of the Persian Gulf (to which he refers for a further answer to
mine), observes, " that if the calculation of Nearchus and the
statement of Pliny are to be depended on, the gulf actually
occupied the present supposed site of Babylon ; so that it was
physically impossible for the tower of Babel to be erected
at or near" that spot, or of course for Noah to have resided
there. The calculation of Nearchus is, that from the gulf to
Babylon was 3300 stadia, and the statement of Pliny, that
Alexandria, when built by Alexander, on the site of" Charax,
was but ten stadia from the sea, while Juba in his time gave it
as about 50 miles, and the Arab embassadors and the Roman
merchants said it was then about 120." (lib. vi. cap. 27.) This,
Mr. Beke considers, seems to give us " the actual rate" of
encroachment of the Delta on the gulf during 400 years. But
we may go much further, and ascertain, with precision amply
sufficient for the present question, the state of circumstances
at more than half way, according to common chronology, be-
tween our own time and the Deluge. Nearchus, we know, con-
ducted Alexander's fleet up the gulf to the Delta in 325 B.C.
Following the course of Nearchus, as given in his own clear
account of the voyage preserved by Arrian, from his arrival
at the Arosis, the river at the N.E. next before coming to the
streams of the Delta, in his progress to Kataderbis and the
island of Margastana, in his passage through the channel over
the shoals to his arrival at Diridotis (by the Khore Abdallah),

at the dispersion, and the Assyrian of later days " set up the towers and
raised up the palaces thereof." To support the present reading, Gen.
x.* 11., which makes Asshur a man, rather than, as in the margin Targums
Onkelos and Babylon, the land Asshur or Assyria, we are to suppose the
author of Genesis in relating a pedigree mentioned among the descendants
of Ham, one of the descendants of Shem, whose birth he had not yet even
noticed, but proceeds afterwards to relate in its proper place and order.
And then why was Babel only " the beginning of his kingdom," if we are
not to understand that it was Nimrod who also * builded Nineveh," &c. ?
As to the omission of the preposition ■ to*, " to Assyria," it occurs in the
Hebrew text so often as to be of little moment either way. See Gen.
xxxv. 1. 3. and xlvi. 3.; 1 Sam. x. 8. and xxiii. 4. ; 2 Sam. vi. 10. 12. and
x. 2. &c.

248 Mr. Cartels liemarh on Mr. Beke's Papers

on the S.W. side of the Delta, and comparing it with the
present state of the country, we learn with surprise the small
degree of change which the general characters of the coast have
undergone during the lapse of so many ages. Dr. Vincent,
in his able work " On the Commerce and Navigation of the
Ancients in the Indian Ocean," adverting to this remarkable
fact, observes, that Capt. Howe's chart " explains the journal
of Nearchus as perfectly as if it had been composed by a
person on board of his fleet," (vol. i. p. 423.), and (p. 466.)
" The pilot on board Nearchus's ship steered exactly the same
course" {along the coast of the Delta,) "as Mr. Cluer's Karack
pilot 2000 years afterwards." The junction of the river called
by Arrian the Eulaeus (coming from the N. or N.E.) with the
Tigris by the still existing ancient Hoffar canal, across' which
Alexander sent a part of his fleet while he sailed down the
Eulaeus to the mouths of the Tigris, and so round to meet it,
(Arrian, Exp. Alex. vii. 7.) further shows that to the point in
question any later encroachments on the gulf must be very
unimportant.

This supposed extension of the Delta over nearly 400 miles
seems, moreover, as little aided by Nearchus's calculation of
the distance in his time between the gulf and Babylon. Dr.
Vincent intimates that in calling it 3300 stadia, Nearchus
should be understood as speaking of stadia of about eight to
a mile (412 miles). To this Mr. Beke objects as merely an
estimate of convenience. Now it happens that Pliny, the other
authority, who must have understood Nearchus's terms of di-
stance better than we can, expressly says, (vi. 26.) " Euphrate
navigari Babylonem e Persico mari 412 mill, pass." (about 412
miles) " tradunt Nearchus et Onesicritus." The latter was pi-
lot and master of Alexander's own ship. Then as to Juba's
opinion Pliny goes on to say, " Juba a Babylone Characem
175 mill. pass. ;" that is, Juba (the second) made it in his time,
adding the 50 miles he accounted it from Charax to the sea,
225 miles onlv from the sea to Babylon, and this was 340
years after the calculation of Nearchus and Onesicritus which
made it 412. So that we shall, perhaps, be inclined to con-
cur with Pliny in the remark, " Inconstantiam mensurse diver-
sitas auctorum facit." From such discordant opinions it is hard
to " learn the true measure," rather than infer from them
" the actual rate at which the Persian Gulf had been filled
up during the 400 years immediately preceding his time."

Mr. Beke animadverts on Mr. Lyell's speaking of the union
of the Euphrates and Tigris as if not manifestly within the
historic aera (in Geology, vol. i.), seeing that Pliny (vi. 27.)
says that in ancient times some made it 25 miles between their

on the Gopher-wood and the Persian Gulf. 249

mouths, and some 7. But it appears from Pliny's account,
that long before his time they had united above the embou-
chure somewhere, not, as Mr. Beke's paper implies, by en-
croachments on the gulf and formation of delta, but simply
by the labour of hands; for Pliny immediately adds, " sed
longo tempore Euphratem praeclusere Orcheni et accolge agros
rigantes nee nisi Pasitigris defertur in mare." And that the
stream thus cut off was only one of the streams of the Delta
called in the country, as Dr. Vincent says it is to this day, the
mouth of the Euphrates, and that these rivers had a higher
junction, seems to be the only inference from other ancient
authorities, as Arrian, who, while in his Expedition of Alexan-
der he says, " the Euphrates disappears in the marshes," and
again,'" the Tigris falls into the Persian Gulf;... where the
Euphrates terminates there is not much water, it is marshy,
and its course is staid*," in his Voyage of Nearchus makes
him arrive at its mouth, giving it no doubt its local appella-
tion given it by his narrator. Pliny, whose account of the two
rivers is not very explicable, adds to the opinions of Juba,&c:
" Some state, that beyond Babylon the Euphrates flows in
one channel for 87 miles before it is drawn off into several
courses on the confines of Charaxf ." Taking this to be the
Tigris, and connecting it with his notion about the disappear-
ance of the Euphrates, we obtain an intimation of their junc-
tion at Khorna, where they now meet, more than 100 miles
inland. Strabo observes, that Eratosthenes (about 500 b. c.)
had spoken of the figure " which the Tigris and Euphrates
make falling together into one ;" and Onesicritus, of both
rivers as flowing into a lake, and the Euphrates as flowing out
of it to the seaj. Mela says, that " the Euphrates does not
continue to the ocean... ceases in a slender stream, and has no
mouth §." Ptolemy, although he repeatedly mentions the
mouths of the Tigris, has noticed none to the Euphrates, and
appears to refer to their junction as far inland j] ; while Justin
states that " the Tigris is received into the marshes of the

* JLig Tsuocyvi 6 ~Ev(p^otrn; ec(pxvt^srctt. — Arrian,Exp.Alex.,\\b. v. cap. 4.
'O liiy^ig...ta%cih'hu s; tou tcovtov tou Usgaizou ov ttoTw v%co(> 6 EutpQocrr,;
rshivrau x.cct Ttvctyoihns sg raro ara<; wTroTrccvsrxt. — Ibid. lib. vii. cap. 7.

f "Fiucre, aliqui, ultra Babylonem continuo alveo priusquam distrahi-
tur ad rigua 87 mill. pass, ubi desinit alveo munire ad confinium Characis
accedente tractu." — Pliny, Nat. Hist., lib. vi. cap. 26.

% 'O TOivoi ovftTrnrTO'jTtc a; h 6 re Ttyyg kou 6 Ev(p^otTYis...cog (pwt.
—Strabo, lib. ii. p. 79- et p. 729.

$" Euphrates non perdurat in pelagus... tenuis rivus despectus emoritur,
etnusquam manifesto exitu effluit sed deficit."— Mela, lib. iii. cap. 8.

i| Ptolemy, p. 145—149.
Third Series. Vol. 5. No. 28. Oct. 1834. 2 K

250 Mr. Carter's "Remarks on Mr. Beke's Papers

Euphrates*." What the single stream to the Delta was called,
whether by the name of the Tigris or of the Euphrates, does
not seem very important ; but notwithstanding some discre-
pancies, the conclusion from the above authorities surely is,
that they have at a very early period, and probably always,
united inland somewhere. Dr. Vincent (i.422.) says, " Khorna,
I am persuaded, was the grand confluence in all ages." But
the large and numerous canals cut in very early times about
this country, combined with the many streams of the Delta,
have given rise to misconceptions as to the true course of the
parent rivers. These streams offer the natural indications of
the commencement of the Delta below Bosra, (or Bossora,
about 70 miles from the sea,) where, as usual, from the want
of slope and momentum, the water begins to multiply its
channels.

If, then, the situation of the Delta, during more than one
half of the interval between our time and the Flood, afford any
illustration of its state during the other, the presence of the
gulf at 300 or 400 miles from its present limit did not preclude
the residence of Noah in that vicinity. But Mr. Beke, quoting
from Mr. Rich's first memorial on Babylon a statement of an
extensive inundation of the Euphrates (continuing for three
or four months of the year), infers that the country in the
neighbourhood of Babylon, if not occupied by the gulf, must
at the time of the building of Babel have been " unfit for hu-
man habitation," from its flooded condition. That, however,
does not appear to be a necessary consequence. It should
seem that there was less rain, and that the waters were not
in such excess at an early period (Polyclites ap. Strab. 742. ;
Arrian, Ex. Alex. vii. 21.; Herod. Cliol79.; Mela, i. 11.) ;—
and the objection would equally apply to the other postdiluvian

* "Tigris in paludesEuphratisrecipitur." — Justin, lib.xlii. cap. 3. Though
Strabo's report of Eratosthenes is of an actual junction of the rivers, a
falling together into one, he says of both Tigris and Euphrates, it goes
to the sea. (lib. xii. 521. and xi. 522.) Herodotus says the same (Clio 20.
Erato 180.) ; and Arrian, we see, though he speaks of the Euphrates
disappearing in the lakes or marshes, mentions its mouth. Arrian is above
explained. The other statements are true now, that is, both rivers be-
ing in the same channel till the waters begin to diverge at Bosra, then
passing on partly by the canal to the Khore Abdallah, and partly by the
channel to the Delta. Ptolemy's eastern and western mouth of the Tigris
indicate exactly the present state of the river. Thus Eratosthenes, Arrian,
Mela, Justin, Ptolemy, Pliny, all understood that the distinct course of
one river failed. A river into a lake may be considered either as termi-
nated there, or continued by a stream issuing at the other end. There is
no necessary disagreement of any of them with Nearchus, and if there
had been, it could not compete with the plain details of his close personal
observation.

on the Gopher-wood and the Persian Gulf. 251

settlements, as the cities of the plain, Egypt, and especially
Nineveh, — contemporaneous with Babel, in " the lowlands of
the Tigris," a valley 8 or 10 miles broad, and where the
floods were so great that " of old it was like a pool of water."
(Nahum ii. 8.).

In my paper I referred to the productions of" the climate"
only where the ark was built, not to the particular country, —
to the vicinity of Babylon, — as Mr. Beke has taken it. But place
the abode of Noah in any of the spots that have been assigned
for the residence of the antediluvian race, in either Mesopo-
tamia or Palestine, we have still together pits of native bitu-
men and a country propitious to the cypress. Diod. Sicu.
(xix. 702.) states that Antigonus (about 313 B.C.) procured
supplies of cypress-trees from Lebanon, " Suvpa&v to ts xa-
\o$ km peyeQos". of surprising magnitude and beauty. Baro-
nius, Ann. Eccles. ad A. 714., mentions " the fleet of the Sa-
racens hastening from Alexandria to Phoenicia to cut cypress-
trees ;" in both instances for the purpose of ship-building :
and see Gen. xiv. 10. As to the country of Babylon, its dry
soil appears to have been most propitious to this tree, and to
none other fitted for that use. We learn from Diod. Sicu.
(lib. ii. c. 1.) that in the ancient bridge at Babylon, said to
have been built by Semiramis, cypress-wood was employed.
And Arrian # reports of Aristobulus, who accompanied Alex-
ander the Great : " He says that Alexander had another fleet,
built of the cypresses cut inBabylonia, for of these trees alone
there was an abundant supply, the country of Assyria being
poor in other timber fit for ship-building." The objection,
then, to the cypress being the gopher-wood of the ark, because
not yielded by the country where the ark was built, is not
very forcible.

But even were it admitted to be true that the site of an-
cient Babylon and all the lands S.E. of it to the sea had been
formerly in the gulf, or had been otherwise covered with
water, it would not show that " the ark could not possibly
have been built anywhere in the neighbourhood" alluded to
by me, even taking it to be on that side of the Euphrates, for
my allusion was to the part where the bitumen is produced
from the earth. It is not ascertained that bitumen in any
quantity was ever found nearer to Babylon than Is or Heet.
Herodotus (Clio 179.) expressly states that it came thence for

* Asyci on Kxt ctKKog uvru suotwrYiyeiro s-oXoc re/m/ouri rxg KWocgKraVg
' rocg tv XYi BotGvKauisc tvtuv yet^ /xovai/ tuv \vfoqn £V7ro(>iocv etuxt su tyi yfii^ex,
rav Aocv^iav tuv h cOCKuu oaec sg uxvr^ytecu U7ro(>cog rfiuv tyjv yyu rctvrriv .
—Arrian, Exp, Alex., lib. vii. cap. 19.

2K2

252 Dr. Faraday's Experimental Researches in Electricity.

the buildings of the city- But Heet is 128 miles to the N.W.
of it, and from the intervening country have been obtained
the lime and gypsum employed on them. (Rich, i. 64-.; Buck-
ingham, 453.) The Delta surely did not extend to Heet.
But if Heet had not existence or were inaccessible about the
birth of Peleg, will the same be said of Kerkook, where are
the next nearest pools of bitumen, (Rich, i. Memor. 63.) about
196 miles in a line to the N. and beyond two ridges of moun-
tains (Buckingham, 335, &c.) ? or again, of Arbela, about 46
such miles further north*, near which place, says Strabo,
(lib. vi. 741.) there is a fountain of naphtha, and not noticing
any other product, mentions with this bituminous fountain a
cypress grove.

Upon the whole, then, whether we place the abode of Noah
in the southern part of Mesopotamia or Palestine, in either
of the parts which have been assigned for it there was bitu-
men if it were needed : a motive at that age for seeking a
substitute: "pitch trees" would thus be unknown. The cypress,
of all woods the most suitable, was afforded for his ark; in par-
ticular, Babylonia seems to have offered none other; the
name suggests it: and then, if the ark must have remained in
the same place throughout the cataclysm, and was built where
that left it, even the site of Babylon might have been the spot,
for any impediment the waters of the gulf could offer to the
builder or the waters of the rivers, that, as to them, would
not equally apply to the settlements of Nimrod, which, like
Nineveh, grew to be cities, for their place is, and especially
in the East, where Nineveh was, by the side of a river.
I am, yours, &c.
May 1834. W. G. CARTER.

XXXVII. Experimental Researches in Electricity. — Seventh
Series. By Michael Faraday, D.C.L. F.R.S. Eullerian
Prof. Chem. Royal Institution, Corr. Mcmb. Royal and Imp.
Acadd. of Sciences, Paris, Petersburgh, Florence, Copenhagen,
Berlin, Sfc.

[Continued from p. 181.]

^[ vi. On the primary or secondary Character of' the Bodies
evolved at the Electrodes.

742. "DEFORE the volta-elecirometer could be employed

■"■* in determining, as a general law, the constancy of

electro-decomposition, it became necessary to examine a di-

* D'Anville, indeed, makes Arbela due E. from Mousul, and equidistant
with it from the gulf.

Primary and Secondary Results of Electrolytic Action, 253

stinction, already recognised among scientific men, relative to
the products of that action, namely, their primitive or second-
ary character; and, if possible, by some general rule or prin-
ciple, to decide when they were of the one or the other kind.
It will appear hereafter that great mistakes respecting electro-
chemical action and its consequences, have arisen from con-
founding these two classes of results together.

743. When a substance under decomposition yields at the
electrodes those bodies uncombined and unaltered which the
electric current has separated, then they may be considered
as primary results, even though themselves compounds. Thus
the oxygen and hydrogen from water are primary results ;
and so also are the acid and alkali (themselves compound
bodies) evolved from sulphate of soda. But when the sub-
stances separated by the current are changed at the electrodes
before their appearance, then they give rise to secondary re-
sults, although in many cases the bodies evolved are ele-
mentary.

744. These secondary results occur in two ways, being
sometimes due to the mutual action of the evolving substance
and the matter of the electrode, and sometimes to its action
upon the substances contained in the decomposing conductor
itself. Thus, when carbon is made the positive electrode in
dilute sulphuric acid, carbonic oxide and carbonic acid appear
there instead of oxygen; for the latter, acting upon the matter
of the electrode, produces these secondary results. Or if the
positive electrode, in a solution of nitrate or acetate of lead,
be platina, then peroxide of lead appears there, equally a
secondary result with the former, but now depending upon an
action of the oxygen on a substance in the solution. Again,
when ammonia is decomposed by platina electrodes, nitrogen
appears at the anode * ; but though an elementary body, it is a
secondary result in this case, being derived from the chemical
action of the oxygen electrically evolved there, upon the am-
monia in the surrounding solution (554.). In the same man-
ner when aqueous solutions of metallic salts are decomposed
by the current, the metals evolved at the cathode, though ele-
ments, are always secondary results, and not immediate con-
sequences of the decomposing power of the electric current.

745. Many of these secondary results are extremely valu-
able; for instance, all the interesting compounds which M.
Becquerel has obtained by feeble electric currents are of this
nature; but they are essentially chemical, and must, in the
theory of electrolytic action, be carefully distinguished from

* Annates de Chimie, 1804, torn. li. p. 167.

254 Dr. Faraday's Experimental Researches in Electricity.

those which are directly due the action of the electric cur-
rent.

746. The nature of the substances evolved will often lead
to a correct judgement of their primary or secondary charac-
ter, but is not sufficient alone to establish that point. Thus,
nitrogen is said to be attracted sometimes by the positive and
sometimes by the negative electrode, according to the bodies
with which it may be combined (554. 555.), and it is on such
occasions evidently viewed as a primary result* ; but I think
I shall show, that, when it appears at the positive electrode,
or rather at the anode, it is a secondary result (748. ). Thus,
also, Sir Humphry Davyf, and with him the great body of
chemical philosophers, (including myself,) have given the ap-
pearance of copper, lead, tin, silver, gold, &c, at the negative
electrode, when their aqueous solutions were acted upon by
the voltaic current, as proofs that the metals, as a class, were
attracted to that surface; thus assuming the metal in each
case to be a primary result. These however, I expect to
prove, are all secondary results; the mere consequence of
chemical action, and no proofs of the attraction or the law an-
nounced J.

747. But when we take to our assistance the law of constant
electro-chemical action already proved with regard to water
(732.), and which I hope to extend satisfactorily to all bodies
(821.), and consider the quantities as well as the nature of the
substances set free, a generally accurate judgement of the
primary or secondary character of the results may be formed :
and this important point, so essential to the theory of electro-
decomposition, since it decides what are the particles directly
under the influence of the current, (distinguishing them from
such as are not affected,) and what are the results to be ex-
pected, may be established with such degree of certainty as
to remove innumerable ambiguities and doubtful considera-
tions from this branch of the science.

748. Let us apply these principles to the case of ammonia,
and the supposed determination of nitrogen to one or the other
electrode (554. 555.). A pure strong solution of ammonia is
as bad a conductor, and therefore as little liable to electro-

* Annates de Chimie, 1 804, torn. li. p. 172.

+ Elements of Chemical Philosophy, pp. 144, 161.

J It is remarkable that up to 1804 it was the received opinion that the
metals were reduced by the nascent hydrogen. At that date the general
opinion was reversed by Hisinger and Berzelius (Annates de Chimie, 1804,
torn. li. p. 174.), who stated that the metals were evolved directly by the
electricity ; in which opinion it appears, from that time, Davy coincided
(Philosophical Transactions, 1826, p. 388.); [or Phil. Mag. and Annals,
N.S. vol. i. p. 35.-Edit.]

Primary and Secondary Results of Electrolytic Action. 255

decomposition, as pure water; but when sulphate of ammonia
is dissolved in it, the whole becomes a conductor; nitrogen
almost and occasionally quite pure is evolved at the anode, and
hydrogen at the cathode; the ratio of the volume of the former
to that of the latter varying, but being as 1 to about 3 or 4.
This result would seem at first to imply that the electric cur-
rent had decomposed ammonia, and that the nitrogen had
been determined towards the positive electrode. But when
the electricity used was measured out by the volta-electrome-
ter (707. 736.), it was found that the hydrogen obtained was
exactly in the proportion which would have been supplied by
decomposed water, whilst the nitrogen had no certain or con-
stant relation whatever. When, upon multiplying experiments,
it was found that, by using a stronger or weaker solution, or
a more or less powerful battery, the gas evolved at the anode
was a mixture of oxygen and nitrogen, varying both in pro-
portion and absolute quantity, whilst the hydrogen at the
cathode remained constant, no doubt could be entertained that
the nitrogen at the anode was a secondary result, depending
upon the chemical action of the nascent oxygen, determined
to that surface by the electric current, upon the ammonia in
solution. It was the water, therefore, which was electrolyzed,
not the ammonia. Further, the experiment gives no real in-
dication of the tendency of the element nitrogen to either one
electrode or the other; nor do I know of any experiment with
nitric acid, or other compounds of nitrogen, which shows the
tendency of this element, under the influence of the electric
current, to pass in either direction along its course.

749. As another illustration of secondary results, the effects
on a solution of acetate of potassa may be quoted. When a
very strong solution was used, more gas was evolved at the
anode than at the cathode, in the proportion of 4 to 3 nearly :
that from the anode was a mixture of carbonic oxide and car-
bonic acid ; that from the cathode pure hydrogen. When a
much weaker solution was used, less gas was evolved at the
anode than at the cathode; and it now contained carburetted hy-
drogen, as well as carbonic oxide and carbonic acid. This
result of carburetted hydrogen at the positive electrode has a
very anomalous appearance, if considered as an immediate
consequence of the decomposing power of the current. It,
however, as well as the carbonic oxide and acid, is only a se-
condary result ; for it is the water alone which suffers electro-
decomposition, and it is the oxygen eliminated at the anode
which, reacting on the acetic acid, in the midst of which it is
evolved, produces those substances that finally appear there.
This is fully proved by experiments with the volta-electrome-

256 Dr. Faraday's Experimental Researches in Electricity.

ter (707.); for then the hydrogen evolved from the acetate at
the cathode is always found to be definite, being exactly pro-
portionate to the electricity which has passed through the so-
lution, and, in quantity, the same as the hydrogen evolved in
the vol ta- electrometer itself. The appearance of the carbon
in combination with the hydrogen at the positive electrode,
and its non-appearance at the negative electrode, are in curious
contrast with the results which might have been expected
from the law usually accepted respecting the final places of
the elements.

750. If the salt in solution be an acetate of lead, then the
results at both electrodes are secondary, and cannot be used
to estimate or express the amount of electro-chemical action,
except by a circuitous process (843.). In place of oxygen, or
even the gases already described (74-9.), peroxide of lead now
appears at the positive, and lead itself at the negative elec-
trode. When other metallic solutions are used, containing,
for instance, peroxides, as that of copper, combined with this
or any other decomposable acid, still more complicated results
will be obtained ; which, viewed as direct results of the electro-
chemical action, will, in their proportions, present nothing
but confusion, but will appear perfectly harmonious and simple
if they be considered as secondary results, and will accord in
their proportions with the oxygen and hydrogen evolved from
water by the action of a definite quantity of electricity.

751. I have experimented upon many bodies, with a view
to determine whether the results were primary or secondary.
I have been surprised to find how many of them, in ordinary
cases, are of the latter class, and how frequently water is the
only body electrolyzed in instances where other substances
have been supposed to give way. Some of these results I will
give in as few words as possible.

752. Nitric Acid. — When very strong, it conducted well,
and yielded oxygen at the positive electrode. No gas appeared
at the negative electrode; but nitrous acid, and apparently
nitric oxide, were formed there, which, dissolving, rendered
the acid yellow or red, and at last even effervescent, from the
spontaneous separation of nitric oxide. Upon diluting the
acid with its bulk or more of water, gas appeared at the nega-
tive electrode. Its quantity could be varied by variations,
either in the strength of the acid or of the voltaic current : for
that acid from which no gas separated at the cathode, with a
weak voltaic battery, did evolve gas there with a stronger ;
and that battery which evolved no gas there, with a strong
acid, did cause its evolution with an acid more dilute. The
gas at the anode was always oxygen; that at the cathode hy-

Primary and Secondary Results of Electrolyzation. 257

drogen. When the quantity of products was examined by
the volta-electrometer (707. ), the oxygen, whether from
strong or weak acid, proved to be in the same proportion as
from water. When the acid was diluted to specific gravity
1*24, or less, the hydrogen also proved to be the same in
quantity as from water. Hence I conclude that the nitric
acid does not undergo electro-chemical decomposition, but
the water only; that the oxygen at the anode is always a pri-
mary result, but that the products at the cathode are often se-
condary, and due to the reaction of the hydrogen upon the
nitric acid.

753. Nitre. — A solution of this salt yields very variable re-
sults, according as one or other form of tube is used, or as
the electrodes are large or small. Sometimes the whole of
the hydrogen of the water decomposed may be obtained at the
negative electrode ; at other times, only a part of it, because
of the ready formation of secondary results. The solution is
a very excellent conductor of electricity.

75i. Nitrate of ammonia, in aqueous solution, gives rise to
secondary results very varied and uncertain in their propor-
tions.

755. Sulphurous Acid. — Pure liquid sulphurous acid does
not conduct nor suffer decomposition by the voltaic current*,
but, when dissolved in water, the solution acquires conducting
power, and is decomposed, yielding oxygen at the anode, and
hydrogen and sulphur at the cathode.

756. A solution containing sulphuric acid in addition, was
a better conductor. It gave very little gas at either electrode :
that at the anode was oxygen, that at the cathode pure hydro-
gen. From the cathode also rose a white turbid stream, con-
sisting of diffused sulphur, which soon rendered the whole
solution milky. The volumes of gases were in no regular
proportion to the quantities evolved from water in the volta-
electrometer. I conclude that the sulphurous acid was not at
all affected by the electric current in any of these cases, and
that the water present was the only body electro-chemically
decomposed ; that, at the anode, the oxygen from the water
converted the sulphurous acid into sulphuric acid, and, at the
cathode, the hydrogen electrically evolved decomposed the
sulphurous acid, combining with its oxygen, and setting its
sulphur free. I conclude that the sulphur at the negative
electrode was only a secondary result ; and, in fact, no part of
it was found combined with the small portion of hydrogen

* See also De la Rive, Bibliotheque Universelte, torn. xl. p. 205; or
Quarterly Journal of Science, vol. xxvii. p. 407.

TAird Series. Vol. 5. No. 28. Oct. 1834. 2 L

258 Dr. Faraday's Experimental Researches in Electricity.

which escaped when weak solutions of sulphurous acid were
used.

757. Sulphuric Acid. — I have already given my reasons for
concluding that sulphuric acid is not electrolyzable, i. e. not
decomposable directly by the electric current, but occasionally
suffering by a secondary action at the cathode from the hydro-
gen evolved there (681.). In the year 1800, Davy considered
the sulphur from sulphuric acid as the result of the action of
the nascent hydrogen*. In 1804-, Hisinger and Berzelius
stated that it was the direct result of the action of the voltaic
pilef ; an opinion which from that time Davy seems to have
adopted, and which has since been commonly received by all.
The change of my own opinion requires that I should correct
what I have already said of the decomposition of sulphuric
acid in a former series of these Researches (552.): I do not
now think that the appearance of the sulphur at the negative
electrode is an immediate consequence of electrolytic action.

758. Muriatic Acid. — A strong solution gave hydrogen at
the negative electrode, and chlorine only at the positive elec-
trode ; of the latter, a part acted on the platina and a part
was dissolved. A minute bubble of gas remained ; it was not
oxygen, but probably air previously held in solution.

759. It was an important matter to determine whether the
chlorine was a primary result, or only a secondary product,
due to the action of the oxygen evolved from water at the
anode upon the muriatic acid ; i. e. whether the muriatic acid
was electrolyzable, and if so, whether the decomposition was
definite.

760. The muriatic acid was gradually diluted. One part
with six of water gave only chlorine at the anode. One part
with eight of water gave only chlorine; with nine of water, a
little oxygen appeared with the chlorine : but the occurrence
or non-occurrence of oxygen at these strengths depended, in
part, on the strength of the voltaic battery used. With fifteen
parts of water, a little oxygen, with much chlorine, was evolved
at the anode. As the solution was now becoming a bad con-
ductor of electricity, sulphuric acid was added to it: this
caused more ready decomposition, but did not sensibly alter
the proportion of chlorine and oxygen.

761. The muriatic acid was now diluted with 100 times its
volume of dilute sulphuric acid. It still gave a large propor-
tion of chlorine at the anode, mingled with oxygen ; and the
result was the same, whether a voltaic battery of 40 pairs of

* Nicholson's Quarterly Journal, vol. iv. pp. 280, 281.
t Annates de Chimie, 1804, torn. li. p. 173.

Primary and Secondary Results of Electrolyzation, 259

plates or one containing only 5 pairs were used. With acid of
this strength, the oxygen evolved at the anode was to the hy-
drogen at the cathode, in volume, as 17 is to 64; and there-
fore the chlorine would have been 30 volumes, had it not been
dissolved by the fluid.

762. Next, with respect to the quantity of elements evolved.
On using the volta-electrometer, it was found that, whether
the strongest or the weakest muriatic acid were used, whether
chlorine alone or chlorine mingled with oxygen appeared at
the anode, still the hydrogen evolved at the cathode was a
constant quantity, i. e. exactly the same as the hydrogen which
the same quantity of electricity could evolve from water.

763. This constancy does not decide whether the muriatic
acid is electrolyzed or not, although it proves that if so, it
must be in definite proportions to the quantity of electricity
used. Other considerations may, however, be allowed to de-
cide the point. The analogy between chlorine and oxygen,
in their relations to hydrogen, is so strong, as to lead almost
to the certainty, that, when combined with that element, they
would perform similar parts in the process of electro-decom-
position. They both unite with it in single proportional
or equivalent quantities; and, the number, of proportionals
appearing to have an intimate and important relation to the
decomposability of a body (697.), those in muriatic acid, as
well as in water, are the most favourable, or those, perhaps
even necessary to decomposition. In other binary compounds
of chlorine also, where nothing equivocal depending on the
simultaneous presence of it and oxygen is involved, the chlo-
rine is directly eliminated at the anode by the electric current.
Such is the case with the chloride of lead (395.), which may
be justly compared with protoxide of lead (402.), and stands
in the same relation to it as muriatic acid to water. The
chlorides of potassium, sodium, barium, &c, are in the same
relation to the protoxides of the same metals, and present the
same results under the influence of the electric current (402.).

764. From all the experiments, combined with these con-
siderations, I conclude that muriatic acid is decomposed by
the direct influence of the electric current, and that the quan-
tities evolved are, and therefore the chemical action is, definite

for a definite quantity of electricity. For though I have not
collected and measured the chlorine, in its separate state, at
the anode, there can exist no doubt as to its being propor-
tional to the hydrogen at the cathode', and the results are
therefore sufficient to establish the general law of constant
electro-chemical action in the case of muriatic acid.

765. In the dilute acid (761.), I conclude that a part of the

2L2

260 Dr. Faraday's Experimental Researches in Electricity,

water is electro- chemically decomposed, giving origin to the
oxygen, which appears mingled with the chlorine at the anode.
The oxygen may be viewed as a secondary result ; but I in-
cline to believe that it is not so: for, if it were, it might be
expected in largest proportion from the stronger acid, whereas
the reverse is the fact. This consideration, with others, also
leads me to conclude that muriatic acid is more easily decom-
posed by the electric current than water; since, even when
diluted with eight or nine times its quantity of the latter fluid,
it alone gives way, the water remaining unaffected.

766. Chlorides, — On using solutions of chlorides in water,
— for instance, the chlorides of sodium or calcium, — there
was evolution of chlorine only at the positive electrode, and
of hydrogen, with the oxide of the base, as soda or lime, at
the negative electrode. The process of decomposition may
be viewed as proceeding in two or three ways, all terminating
in the same results. Perhaps the simplest is to consider the
chloride as the substance electrolyzed, its chlorine being deter-
mined to and evolved at the anode, and its metal passing to
the cathode, where, finding no more chlorine, it acts upon the
water, producing hydrogen and an oxide as secondary results.
As the discussion would detain me from more important mat-
ter, and is not of immediate consequence, I shall defer it for
the present. It is, however, of great consequence to state, that,
on using the volta-electrometer, the hydrogen in both cases
was definite ; and if the results do not prove the definite de-
composition of chlorides, (which shall be proved elsewhere, —
789. 794*. 814,) they are not in the slightest degree opposed
to such a conclusion, and do support the general law,

767. Hydriodic Acid,— A solution of hydriodic acid was
affected exactly in the same manner as muriatic acid. When
strong, hydrogen was evolved at the negative electrode, in
definite proportion to the quantity of electricity which had
passed, i. e, in the same proportion as was evolved by the
same current from water; and iodine without any ox}'gen was
evolved at the positive electrode. But when diluted, small
quantities of oxygen appeared with the iodine at the anode,
the proportion of hydrogen at the cathode remaining undis-
turbed.

768. I believe the decomposition of the hydriodic acid in
this case to be direct, for the reasons already given respecting
muriatic acid (763. 764?.).

769. Iodides, — A solution of iodide of potassium being sub-
jected to the voltaic current, iodine appeared at the positive
electrode (without any oxygen), and hydrogen with free alkali
at the negative electrode. The same observations as to the

Primary and Secondary Results of ' Electrolyzatiofi. 261

mode of decomposition are applicable here as were made in
relation to the chlorides when in solution (766.).

770. Hydro-fluoric Acid and Fluorides. — Solution of hydro-
fluoric acid did not appear to be decomposed under the in-
fluence of the electric current : it was the water which gave
way apparently. The fused fluorides were electrolyzed (417.);
but having during these actions ohinmed fluorine in the sepa-
rate state, I think it better to refer to a future series of these
Researches, in which I purpose giving a fuller account of the
results than would be consistent with propriety here.

771. Hydro-cyanic acid in solution conducts very badly.
The definite proportion of hydrogen (equal to that from
water) was set free at the cathode, whilst at the anode a small
quantity of oxygen was evolved and apparently a solution of
cyanogen formed. The action altogether corresponded with
that on a dilute muriatic or hydriodic acid. When the hydro-
cyanic acid was made a better conductor by sulphuric acid,
the same results occurred.

Cyanides. — With a solution of the cyanide of potassium,
the result was precisely the same as with a chloride or iodide.
No oxygen was evolved at the positive electrode, but a brown
solution formed there. For the reasons given when speaking
of the chlorides (766.), and because a fused cyanide of potas-
sium evolves cyanogen at the positive electrode*, I incline to
believe that the cyanide in solution is directly decomposed.

772. Ferro-cyanic acid and the Jerro-cyanides, as also sid-
pho-cyanic acid and the sulpho-cyanides, presented results cor-
responding with those just described (771.).

773. Acetic Acid — Glacial acetic acid, when fused (405.),
is not decomposed by, nor does it conduct, electricity. On
adding a little water to it, still there were no signs of action ;
on adding more water, it acted slowly and about as water
alone would do. Dilute sulphuric acid was added to it in
order to make it a better conductor; then the definite propor-
tion of hydrogen was evolved at the cathode, and a mixture
of oxygen in very deficient quantity, with carbonic acid, and
a little carbonic oxide, at the anode. Hence it appears that
acetic acid is not electrolyzable, but that a portion of it is de-
composed by the oxygen evolved at the anode, producing se-
condary results, varying with the strength of the acid, the in-
tensity of the current, and other circumstances.

774. Acetates.— One of these has been referred to already,

* It is a very remarkable thing to see carbon and nitrogen in this case
determined powerfully towards the positive surface of the voltaic battery j
but it is perfectly in harmony with the theory of electro-chemical decom-
position which I have advanced.

262 Dr. Faraday's Experimental Researches in Electricity.

as affording only secondary results relative to the acetic acid
(749.). With many of the metallic acetates the results at
both electrodes are secondary (746. 750.).

Acetate of soda fused and anhydrous is directly decomposed,
being, as I believe, a true electrolyte, and evolving soda and
acetic acid at the cathode and anode. These, however, have no
sensible duration, but are immediately resolved into other sub-
stances ; charcoal, sodiuretted hydrogen, &c, being set free
at the former, and as far as I could judge under the circum-
stances, acetic acid mingled with carbonic oxide, carbonic
acid, &c, at the latter.

775. Tartaric Acid. — Pure solution of tartaric acid is almost
as bad a conductor as pure water. On adding sulphuric acid
to it, it conducted well, the results at the positive electrode
being primary or secondary in different proportions, according
to variations in the strength of the acid and the power of the
electric current (752.). Alkaline tartrates gave a large pro-
portion of secondary results at the positive electrode. The
hydrogen at the negative electrode remained constant unless
certain metallic salts were used.

776. Solutions of salts containing other vegetable acids, as
the benzoates ; of sugar, gum, &c, dissolved in dilute sul-
phuric acid; of resin, albumen, &c, dissolved in alkalies, were
in turn submitted to the electrolytic power of the voltaic cur-
rent. In all these cases, secondary results to a greater or
smaller extent were produced at the positive electrode.

777. In concluding this division of these Researches, it can-
not but occur to the mind that the final result of the action
of the electric current upon substances placed between the
electrodes, instead of being simple may be very complicated.
There are two modes by which these substances may be de-
composed, either by the direct force of the electric current, or
by the action of bodies which that current may evolve. There
are also two modes by which new compounds may be formed,
i. e. by combination of the evolving substances whilst in their
nascent state (658.), directly with the matter of the electrode;
or else their combination with those bodies, which being con-
tained in, or associated with, the decomposing conductor, are
necessarily present at the anode and cathode. The complexity
is rendered still greater by the circumstance that two or more
of these actions may occur simultaneously, and also in variable
proportions to each other. But it may in a great measure
be resolved by attention to the principles already laid down

(747.).

778. When aqueous solutions of bodies are used, secondary
results are exceedingly frequent. Even when the water is not

Primary and Secondary Results of Electrolyzation. 263

present in large quantity, but is merely that of combination,
still secondary results often ensue : for instance, it is very
possible that in Sir Humphry Davy's decomposition of the
hydrates of potassa and soda, a part of the potassium pro-
duced was the result of a secondary action. Hence, also, a
frequent cause for the disappearance of the oxygen and hy-
drogen which would otherwise be evolved : and when hydro-
gen does not appear at the cathode in an aqueous solution, it
perhaps always indicates that a secondary action has taken
place there. No exception to this rule has as yet occurred to
my observation.

779. Secondary actions are not confined to aqueous solutions,
or cases where water is present. For instance, various chlo-
rides acted upon, when fused (402.), by platina electrodes,
have the chlorine determined electrically to the anode. In
many cases, as with the chlorides of lead, potassium, barium,
&c, the chlorine acts on the platina and forms a compound
with it, which dissolves ; but when protochloride of tin is used,
the chlorine at the anode does not act upon the platina, but
upon the chloride already there, forming a perchloride which
rises in vapour (790. 804.). These are, therefore, instances
of secondary actions of both kinds, produced in bodies con-
taining no water.

780. The production of boron from fused borax (402. 417.),
is also a case of secondary action ; for boracic acid is not
decomposable by electricity (408.), and it was the sodium
evolved at the cathode which, reacting on the boracic acid
around it, took oxygen from it and set boron free in the ex-
periments formerly described.

781. Secondary actions have already, in the hands of M.
Becquerel, produced many interesting results in the forma-
tion of compounds; some of them new, others imitations of
those occurring naturally*. It is probable they may prove
equally interesting in an opposite direction, i. e. as affording
cases of analytic* decomposition. Much information regarding
the composition, and perhaps even the arrangement of the
particles of such bodies as the vegetable acids and alkalies,
and organic compounds generally, will probably be obtained
by submitting them to the action of nascent oxygen, hydro-
gen, chlorine, &c, at the electrodes ; and the action seems the
more promising, because of the thorough command which we
possess over attendant circumstances, such as the strength of
the current, the size of the electrodes, the nature of the de-
composing conductor, its strength, &c, all of which may be

§ Annates de Chimie, torn. xxxv. p. 113.

264« Mr. J. Nixon on the Tides in the Bay of Morecambe,

expected to have their corresponding influence upon the final
result.

782. It is to me a great satisfaction that the extreme variety
of secondary results have presented nothing opposed to the
doctrine of a constant and definite electro-chemical action, to
the particular consideration of which I shall now proceed.

[To be continued.]

XXXVIII. On the Tides in the Bay of Morecambe. By
John Nixon, Esq.*

nPHE beautiful bay of Morecambe extends from the Irish

* Sea seventeen miles in a north-easterly direction. From
the entrance (between Rossal Point and Walney Island) to
Humphrey Point, a distance of fourteen miles, beyond which
the bay contracts into two narrow arms, the width varies from
eleven to fifteen miles.

At the mouth of the bay, situate some little distance below the
parallel of latitude wherein the tidal current from St. George's
Channel meets that from the North Channel, we have shal-
lows to the north-west, and to the south-east deepening water
up to the margin of the sands by the shore. Off Rossal Point
the soundings at low water are nearly thirty fathoms, but the
depth decreases gradually up the same side of the bay, and
towards the opposite shore, as far as to Poulton (a distance
of twelve miles north-east) where the sea ebbs out, or nearly
so, at high tides. From about Poulton draw a line in a di-
rection to bisect the entrance to the bay, and we shall have,
to the right, sands either laid bare, or only one to three fa-
thoms under the sea at low-water spring tides. The Grange
and Furness channels range by opposite shores the length of
these sands, the former conveying at low water to the open
sea the Kent, Winster, and Keer, and the latter the waters
from Windermere and Coniston lakes, &c. After heavy rains
the swoln rivers will sometimes deviate from their previous
course on the sands, and cause the main channels to shift.
From the great width of the bay these noble waters cannot,
however, materially affect the rate or height of the tide ; in
fact, on a calm day they may be seen from the hills along the
coastf, flowing apparently in their usual direction over the
denser sea water, from which they are distinguishable by their
superior smoothness of surface.

Off Heysham, Poulton, Hest-bank, Warton, &c, the tides

• Communicated by the Author. f From Warton Crag in particular.

Mr. J. Nixon on the Tides in the Bay of Morecambe. 265

assume in moderate weather the character of calm tides*,
the slight waves fronting the bottom of the bay with a crest
parallel to a line drawn across its entrance, or from south-west
to north-east. It is, however, probable that rapid currents are
formed by the tide on rounding the headlands which oppose
its progress in the lower part of the bay, as I have observed
the tide make the entire circuit of Silverdale Bay and Point,
strongly agitated and at a tremendous rate, under an opposing
wind of great force f.

The time of high water is not the same throughout the bay,
the greatest differences being supposed to exist between op-
posite parts of the shores. Winds from the south-west quar-
ter, blowing strongly either in the bay or up the Irish Chan-
nel, are considered to accelerate the time of high water and
increase the height of the tides J, retarding, on the other hand,
the time of ebb, and sustaining the waters above their usual
level. Some of the highest tides in the bay have taken place
under similar circumstances at neaps. To winds from the
north-east quarter effects exactly opposite are attributed, those
from the south-east or north-west being termed neutral. The
highest tides, about thirty feet, are held to be about Peel
Castle, where there is only half a fathom of water at spring-
tides, low water ; but those at Heysham, ten miles east of that
locality, it will be proved, are scarcely inferior.

On the Tides at Hest Breakwater,

The breakwater, situate half a mile north-west of Hest-
bank, (a village three miles north of Lancaster,) projects about
fifty yards in a north-west direction from a gravel bank
thrown up as a road to it from the shore, from which it is
nearly three hundred yards distant. It is constructed of solid
masonry, perpendicular on every side to the height of its sur-
face, which is about level with high-water neap tides. The
force of the waves in stormy tides is broken on its south-west
side by a connected sloping bank formed of fragments of rock.
A lofty pole, formerly used for hoisting a lamp, is fixed per-
pendicularly within a stone pedestal let into the surface of the
breakwater at a distance of seven yards from its north-west

* Between Kent's Bank and Silverdale the tide is said to form a bore,
advancing breast high, with a roaring noise, at the full speed of a horse.
(The bore of the Ganges runs at the rate of seventeen miles an hour for
seventy miles.)

t On the 1st of September last, memorable for the number of ship-
wrecks.

% The sailors are of opinion that strong dews and heavy rains increase
the height of a tide (?).

Third Series. Vol. 5, No. 28. Oct. 1834. 2 M

266 Mr. J. Nixon on the Tides in the Bay of Morccambe.

end. The Keer, which, flowing in its usual channel, passed
close by the breakwater at the time of its erection (only a few
years ago), soon after receded from it considerably to the
north-west; and again altering its course after the rainy au-
tumns of 1829 and 1830*, fell into the Grange channel four
or five miles above their previous confluence off* Poulton.
The height of the north-east or lee side of the breakwater,
originally upwards of sixteen feet, is now reduced by the gra-
dual deposition of warp to nine feetf. On this account a
costly structure for the convenient unshipping of goods de-
stined to be forwarded by the Lancaster canal, is now become
unserviceable and suffered to go to ruinj.

In order to find the time, &c, of high water, the east side
of the breakwater pole was divided, from its base upwards,
to a sufficient height, into feet, and after a few days' observa-
tions into half-feet. A board, similarly divided, was nailed per-
pendicularly to one of the piles (the nearest to the pole) on the
lee side of the breakwater, its upper division being placed ex-
actly level with the base of the pole by means of a spirit-level.
From the shore (little above the level of the breakwater) these
divisions, which were marked and numbered with white paint,
were distinctly seen through a 20-inch telescope, and little
difficulty occurred in determining in calm weather, and espe-
cially at high tides, the nearest minute by the watch when
the water appeared level with any division §. With a rough
sea dashing over the breakwater it required most vigilant ob-
servation to decide when the waves fluctuated as much above
as below the mark, or subsided for some moments to the level
of it. The observations at neaps, generally more uncertain,
were facilitated by the comparative tranquillity of the water by
the divided board. The divisions on the pole and board
served also to mark the extreme height of the tide above or
below the surface of the breakwater.

When the perpendicular rise and fall of a tide are uniform
in rate, half the sum of the times at which it has risen and

• At the same period a lew sand-bank, called Priest Skear, lying a mile
north of the breakwater, gradually assumed the form of an island. Not
many years ago it was pasture land connected with the shore, now half a
mile distant.

f This has been explained in Treatises on Harbours. Beneath the warp
lies the red marl with ironstone, ranging between Carnforth and Bare.
It appears to be the same rock which runs in patches between Ingleton
and Kirkby Lonsdale.

X About thirty years ago the Ulverston canal was rendered nearly use-
less by a similar shifting of a branch of the Furness channel.

§ In general it was most difficult to mark with certainty the time when
the sea became level with the bate of the pole.

Mr. J. Nixon on the Tides in the Bay of Morecambe. 267

afterwards descended to the same (height or) division, will
give, alike from observations of every division, the time of
high water; but as the rate will generally vary, not only from
astronomical causes, but also from sudden changes in the force
or direction of the wind, it follows that the series of times ob-
tained from the several divisions will neither coincide with
each other, nor with the true instant, the error increasing
(irregularly) from the highest to the lowest division noted. In
the course of observations, frequently protracted to three hours,
as the extreme difference between the times obtained never
exceeded five minutes, the one derived from the highest divi-
sion rarely required a correction of moment to reduce it to
the true instant of high water.

The watch made use of, which has a detached lever, but
is without compensation-curb, &c, keeps a tolerably uniform
rate when not exposed, as was sometimes the case, to violent
shocks on travelling. Its error was ascertained from time to
time at a station near Hest-bank from sets of observations made
in the afternoon, of the instants the sun's upper and lower limbs
had descended to a certain altitude (measured by a box sex-
tant,) above the sea at the horizon, or later in the afternoon
above its margin (?) about Peel Castle, a distance of 15-f-
miles. The dip of the sea, found by the sector to vary, ac-
cording to the state of the tide and refraction, from 8' 0r/ to
11' 2S", was taken at 10' 0". On one occasion the sun's
height was obtained in the morning by reflection from the
tranquil surface of the canal. (See Table I.) From the
highest* part of the north-east battlement of the canal bridge
on the Oversands road from Hest-bank, go two and a half
feet towards the opposite side of the bridge, and the station,
51 feet distant, (the east end of the roadside wall,) will be in
a line with the breakwater pole. The height of the wall top
above the long level of the Lancaster canal (extending from
Preston nearly to Burton-in-Kendal,) measured 13 feet. The
(trigonometrical) latitude was found to be 54° 5' 34" north,
and the longitude 2° 48' 5" (or 11 min. 12 sec. in time) west
of Greenwich. The distance from Hest-bank wall to the
Breakwater pole, 2339*3 feetf, was calculated from the angles
taken by the four-inch theodolite at both ends of a base line
extending 855 feet (as measured by a corrected tape) along
the west margin of the Oversands road near the bathing-

* In 1829, the fall to the canal was 17 feet 3 inches, and 17 feet in
1832, the fall to the wall top being 4 feet 1 inch.

t Differing little from, but preferable to, the length obtained by a trian-
gulation connected with that of Colonel Mudge.

2 M 2

268 Mr. J. Nixon on the Tides in the Bay of Morecambe.

house. With this distance, and the vertical angles measured
at the wall by the sector, we get

Height of wall above breakwater pole top, (the \ Feet,
mean of three observations in 1829 and 1832, > 43*2
varying from 43*1 to 43*2) J

Height of wall above pole base, (the mean of)

eight observations, in 1829, 1830, and 1832, V 71*2
varying from 70'9 to 71*4) J

Hence the canal will be 30*2 feet above the top, and 58*2
above the base of the pole.

Notwithstanding the present dilapidated state of the break-
water, the measurements do not indicate any alteration of level
in the pedestal of the pole.

Height of Neap and Spring Tides at Hey sham.

The tide deserts Hest sands soon after half-ebb, and at
Poulton, two miles to the west-south-west, it either ebbs out
at spring tides, or is cut off by a two- foot bar of sand. In
Heysham lake, 5 miles south-west of Hest-bank, there is,
however, constantly deep water, communicating without cur-
rent (?) with the open sea.

July 20, 1832, two days before the neap tides were at a
minimum, a stake was driven just within the margin of the
lake down to the exact level of its unruffled surface when at
the lowest (or about 10h 2m a.m., mean time). The height of
high water was marked (in a dead calm) true to an inch or
two (at 3h 57m p.m.) by a similar stake driven (820 yards to the
eastward of the other) into the sands near the road from
Upper Heysham to the shore. The difference of level of the
two marks was found by the six-inch theodolite and two six-
feet levelling staves, divided on both sides into inches, of which
the fractional parts, as the staves were unfurnished with slid-
ing vanes carrying verniers, were visually estimated. The
level (bubble) of the theodolite was properly adjusted, but
from a defect in the screw-key, the line of collimation, which
pointed too high by one tenth of an inch in a distance of fifty
feet, could not be rectified. To meet the evil, the instrument
was invariably placed (between and) equidistant from the two
staves previously set up perpendicularly (by a plumb-line) at
distances from each other not exceeding 100 feet*. Two
staves were indispensable on account of the slight, yet gradual

* Or, when the sum of the distances from the instrument to the staff in
one direction equal the sum of those to the staff in the other direction, a
compensation of errors takes place.

Mr. J. Nixon on the Tides in the Bay of Morecambe. 269

sinking of the heavy instrument within the sand, which re-
quired that both levels should be taken as nearly at the same
time as possible*. The total fall appeared to be 18 feet
6 inches, but a solitary limestone, considered as the standard
height for extreme neaps, was situated 1 foot 9 inches below
the level of our mark, which would reduce the total height of
the tide by double (?) that quantity, or to 15 feet.

July 28, 1832, the day previous to the highest spring tide
(the weather being perfectly calm), the fall from the level of
high water (at llh 32ra a.m.) to our stake near the shore mea-
sured 6 feet 5 inches, but that from the stake by the lake
down to the level of the latter at low water (at 5h 57m p.m.)
did not exceed 4 feet 7 inches, although a continuous fall was
perceptible nearly up to the time quoted f. The total height
of the tide will therefore be 29 feet 3 inches. On this occa-
sion, as the theodolite was completely adjusted, the difference
of level between the two stakes driven down at neaps was
carefully remeasured, and made to be 18 feet 3 inches, or only
3 inches less than previously.

In strictness the rise as well as the fall of a tide should be
obtained, and the mean taken for its correct height.

Measurement by the Dip of the Height of the Tides.
No ray of light originating at any point (P) on the (sphe-
rical) surface of the sea
(PL) could pass below
the level of the hori-
zontal plane PD (which
is perpendicular to the
vertical PC) without
being absorbed in the
sea. At the point of
intersection (D) of this
plane with any other
vertical, as DC, the an-
gle HDP, or depres-
sion of P below the
horizontal plane or line
DH, is termed the true
dip, and is equal to the
arc contained between
the two verticals PC and DC, or the angle PCD.

* As an additional precaution one staff was read off before as well as
after noting the other, and the mean of both readings registered.

f The fishermen hold that there is a difference of half an hour between
the duration of ebb and flow in Hevsham lake.

270 Mr. J. Nixon on the Tides in the Bay of Morecambe,

The ray from P, initially in the direction of D, being con-
stantly curved downwards in its passage from the effects of
atmospherical refraction, will cut the vertical DC at a point
E lower than D by (nearly) the tangent of an angle DPE,
which bears a constant proportion to the true dip (or con-
tained arc). At E the depression of P is evidently less than
at D by the angle PEK = DPE, or the angle of refraction ;
but as P will not be seen from E in the direction EP, but in
a tangent to the extremity of the curved ray at P, it will ap-
pear elevated above P by the angle of refraction : hence the
apparent dip at E will be less than the true dip at D by twice
the angle of refraction *.

DL being the height of D above the level of the sea, that
of E will be equal to DL minus DE (or the part cut off by
refraction). As the angle DPL is constantly half the dip at
D, (or half the contained arc PCD,) it follows that the angle
DPE will bear twice the proportion to that of DPL that the
refraction does to the contained arc. When the height in
feet of E is given, that of D may be found by increasing E by

2 E

-, n being the ratio of the contained arc to the refraction.

72—2' °

Thus, if E be 80 feet, and the refraction y^jth of the arc, then
will the height of D be 80+ £p| = i00 feet. The true

dip for D being 10' 37", that for E will be (10' 37" minus
y^th, or) 9' 33", and its apparent dip (10' 37" minus 1th, or)
8' 30". (The true dip for G (= 80 feet) would be 9' 30", or
3" less than for E.)

Although well aware that the difference between the true
and apparent dip was subject to great and unaccountable
fluctuations, yet I flattered myself that by measuring along
with the depression of the horizon of the sea that of a fixed
object on the shore beyond, situate nearly in the same direc-
tion and at about an equal distance, I should then be able to
ascertain the deviation of the refraction at low water from its
amount at high water, the latter being equal to the difference
between the apparent dip and that calculated from the mea-
sured height of the eye above the sea at the breakwater f.
The plan, which, with one exception, appears to have been

* G, the point of intersection of the unrefracted ray PD with a vertical
at a height equal to that of E, has a less extensive horizon than the latter
by (twice) the arc GE. D is elevated above E, yet their horizons, as that
of the former is not affected by refraction, are equal.

t Any probable difference in the times of high water at the horizon
of the sea and at the breakwater would scarcely exceed the duration

Mr. J. Nixon on the Tides in the Bay of Morecambe. 271

tolerably successful, would probably have been completely so
had the base of Walney lighthouse (the object selected for re-
ference) been observed in lieu of its ill-defined conical top.
At Hest-bank wall, where the measurements were made by
the sector, the height, though scarcely more than requisite
to obtain at low water an unobstructed view of the open sea,
throws its horizon to a distance of 9 to 1 1 miles, and thus
renders it necessary to have the dip true to 3" or 4" in order
to insure to the calculated height of the eye the accuracy of
one foot. The bank is steep, and extends to the south-west
and north-east. At high water the station may be 200 yards
distant from the sea in the direction observed, (a little left of
the lighthouse, which lies to the west by south,) but at low
water sands, intersected by channels and pools of water, in-
tervene for several miles.

Generally each day's observations are arranged below, in
an order to exhibit, — 1st, The variation at low water of the
depression of the lighthouse from its amount at high water;
2nd, the refraction at high water, or difference between the
observed dip and that calculated from the measured height of
the eye ; 3rd, the height of the eye at low water, computed
from the observed dip corrected by a refraction differing from
that obtained at high water by the corresponding variation in
the depression of the lighthouse ; 4th, the dip answering to
the height of the eye at low water, derived from a table,
founded on the measurements at Heysham ; 5th, the conse-
quent error of the estimated refraction and height of the eye.

September 14th, 1829.

(At 0h 5raP.M. Black Comb, 1 42' 21" elev • refr U
126,325 feet distant/4^ Zi eleV* ' retr' ™

10 17 a.m. Lighthouse topi , j

9,863 feet distant/ d *6 Uepr' \ 5' 46"
K 4Q — J

0 5 p.m 5 49

* 2° 5 34i -

6 10 5 31£

}

Variation 0 13

of the hang of the tide. Granting even a difference of level in the sea
at high water at the two localities, we should then form a false estimate
of the refraction, yet as the calculated dip at low water would he nearly
equally in defect or excess with that at high water, their difference, or
height of the tide, would not be materially affected.

272 Mr. J. Nixon on the Tides in the Bay of Morecambe
At 10h 2m a.m. Dip 8' 53"; Eye 70-2 feet ; refr. + O1

10h 2m

10

35

11

0

11

30

11

46

11

58

0 30 P.M.

8 30

— 67-5

8 24±

— 65*4

8 20j

— 64*2

8 24J

— 64-4

8 22

— 64-7

8 30

— 66-7

fO'

1"

0

13

0

11

0

10

0

6i

0

10

0

10

+ 0

84

+ 0

6*

Mean 8 29

Half variation

Mean refraction (8~37^' or) A^ +0 15

At 5h12m p.m. Dip 9'58'r
5 30 10 0

5 45 9 58

6 0 9 55

Low water.

Mean 9 58

Mean refraction -fa +0 18|
Half variation ... +0 64

Corrected dip and height of eye 10' 23" = 95 6 feet.
Tabulated do * 10 27 = 97*0

Errors —0 4 —1*4

September 15th 1829.

At 10h50m a.m. Lighthouse top 5" 49" depr. 1 , „

0 55 p.m. 5 51 — }

6 0 a.m. 4 35 —

(6 5 a.m. Black Comb 42 48 elev. ; refr. T^.)
5 45 p.m. Lighthouse top 5 40 4 depr.

Morning variation — 1' 15"; evening variation —94".

At I0h43m a.m. Dip 8' 454"; Eye 71*3 feet; refr. + 0' 12".

U 5 8 49 — 68*7 -0 1

H 47 8 30i — 64-9 +0 3

0 20 P.M.— 8 29 — 64-0 — — +0 Of
0 48 8 23 — 64-5 +0 84

Mean 8 Z5\ +0 *f

Mean morning refraction (4i+37i) = 8~4o~" = T&y*

Do. evening do. (4|+ 5 ) = ^~a = fr

Mr. J. Nixon on the Tides in the Bay of Morccambe. 273

At 5h45ra a.m.; Dip ... 8' 4.3") Low water,
6 15 ... 8 41 J morning.

Mean 8 42

Refraction T^.j ... +48

Half morning variation + 37i

Corrected dip and height of eye 10 1\ = 91*0 feet.
Tabulated do. 10 30 J = 98-0

Errors —0 23 -7'0

At 5h31m p.m. Dip 9' 50"

6 0 9 50

Low water,
6 20 ... ... 9 52 J eveninS-

}

Mean 9 51

Refraction Jj -flli

Half evening variation + 5

Corrected dip and height of eye 10 7f = 91*0 feet.

Tabulated do. 10 30^ = 98*0

Errors — 0 23 —7'0

In the morning there was a strong white frost, which did
not recur in the evening. To account for our estimate of the
refraction being so much in defect, we must either suppose
our tabulated height of the (equinoctial) tide (34 feet) in ex-
cess, or that the variation of refraction was less for the light-
house than the horizon of the sea, and to precisely the same
amount in the morning as evening ! At noon, which was
bright and warm, the refraction for the dip and the lighthouse
were both less by 4J" than on the preceding day.

September 16th, 1829.
(At 2h35m p.m. Black Comb, 42' 33i" elev. ; refr. (&)

(6 55 a.m. do. 42 55i TV

0 35 p.m. Lighthouse top 5 33± depr.
6 45 a.m. do. 5 12 —

(10 25 a.m. do. 5 17 — )

Variation — 21±"
At 0h23m p.m. dip 8' 17"; Eye 66*3 feet; refr. +21"

0 4i 8 10 — 65'6 25f

1 o 8 4 — 65'3 31

1 18 8 4 — 65*2 31

1 40 8 I — 65'6 34J

Mean ... 8 7 +28 J-

Half variation +10f

rO'39

Mean refraction ... (s-?^) = tV +39

Third Series. Vol. 5. No. 28. Oct. 1 834. 2 N

274 Mr. J. Nixon on the Tides in the Bay of Morccambe.

At 6h30m a.m. dip 11' 13") T

7 0 \ 11 28 |LoW water*

Mean 11 20j

Refraction T^ +57

Half variation + 10J

Corrected dip and height of eve 12 28 = 138*0 feet.
Tabulated do. 10 25 = 96'3 —

Errors +2 3 +41*7 —

The refraction for the dip at noon is unusually great, but
that for Black Comb and the lighthouse, is nearly equally in
excess. The morning was frosty, and the horizon of the sea,
although dull at the first observation for low water, became
quite clear at the second. The refraction appears, however,
to have been 55%f negative', a probable consequence of a
frosty morning succeeding a warm evening, in which case the
air would be considerably cooler than the sea. Under si-
milar circumstances, Biot has observed the dip at sea to be
4 or 5 minutes greater than usual.

August 24th 1829.

At 2h 0m p.m. (Low water) dip 10' 0\n

2 30 9 52f

Mean 9 5Q\

Mean noon refr. Sept. 14, 15, 16 = ?\ +15f

Corrected dip and height of eye 10 12= 92-3 feet.

Tabulated do. ... 10 4| = 90*0 —

Errors +0 7i +2*3 —

Height of eye at high water 92*6 feet. Lighthouse unob-
served.

August 25th, 1829.

At 2h 30m p.m. Low water, dip

O A, K m m -

9' 38"
9 38
9 41

o 1 n ,. „„ .

Mean

Mean noon refraction yl¥

9 39
+ 15

Corrected dip and height of eye
Tabulated do.

9 54 = 87*0 ft.
10 5\ = 90*3

Errors -0 \\\ -3*3

Mr. J. Nixon on the Tides in the Bay of Morecambe. 275

Height of eye at high water, 72 feet. Lighthouse unob-
served.

October 13th, 1830.

At 9h 22m a.m. Lighthouse top, depr. 5' 404".

{High water.
At 9 32 a.m. dip 8' 33"; eye 71*3 ft.; refr. +244 = fa
Between the lighthouse and horizon of the sea, there ap-
peared a bank of white vapour.

High Water. October 14th, 1830.

At 9h42m a.m. dip 8' 414"; eye 70*7 ft.; refr. + 154"

10 12 8 394

10 42 8 40£

70-1

70-7 —

9' 35"

— 134

— 154

Mean ... 8 404
At 4 35 p.m. Low water; dip

+ 15 = *-

Refraction at noon ^

+ 164

Corrected dip and height of eye
Tabulated do.

9 514
10 11

= 86*2 ft.
= 92-0

Errors —0 194 — 5'8

The refraction ( + 36") must have been more than double
its value at the time of high water.

October 15th, 1830.
High water.

At 9h58m a.m. dip 8'45V; eye 70*7 ft.; refr.+ 104
10 19 8 374 — 69-7 144

10 48 8 40 — 68-3 6£

11 16 8 394 — ■ 69-7 124

Mean ... 8 404 — +11 = ?8.

October 16th, 1830.

High-water,

At llh 8m a.m. dip 8' 41"; eye 68-5 ft.; refr. +5
1131 8 35 — 68-4 12

Mean ... 8 38 +8401*^-

2 N2

276 Mr. J. Nixon on the Tides in the Bay of Morecambe.
Table I. Observations for determining the Error of the Watch

1832.

Alti-
tude.

Sun's L.L.

Sun's U. L.

Error,
mean time.

Daily Rate.

July 7» p.m.

29° 30'

4h49ra25s

4h53m 0' t
4 59 5J

-+- 3m30»

A

28 30

4 56 5

sec. "2

+38 |

+34 1

10.

32 5

4 32 0

4 35 30

+ 5 22

12.

31 0

4 39 0

4 42 50 \

4 49 45 j

+ 6 30

30 0

4 46 35

1 o>

14.

32 0

4 31 40

4 35 25 1

+ 25 +

30 30

4 42 14

4 45 55 [

+ 7 20

II

29 0

4 52 40

4 56 15 J

+60 |

18.

24 0

5 27 10

531 oi

+ 11 23

23 0

5 34 30

5 38 20 J

2

23.

32 30

4 28 25

4 32 20 i

+49 £

31 30

4 35 5

4 39 15 [

+ 15 26

«S

30 30

5 42 10

* * *

g

26.

22 30

5 35 10

5 38 52 "I

+33 £

21 30

5 42 0

5 45 47 V

+ 17 5

<u

20 30

5 48 50

5 22 20 J

+20 g

f Aug. 1. A.M.

19 45

7 2 25

* * *

+18 56

d

7. P.M.

21 0

5 34 45

5 38 20

+23 28

+42 |

Table J I. Register of the Tides at Hest-Bank.

Explanation of the Columns. — 1st, The day of the month.
2nd, The number of divisions (on the breakwater pole) ob-
served : the asterisk denotes that the corresponding times for
high water increased or decreased seriatim. 3rd, The height
of the top of the pole above the level of the tide at high water.
4th, The instant of high water calculated immediately from
the times, by the watch, at which the tide reached (during the
flow and ebb) the level of the several divisions observed.
5th, The last column corrected for the error of the watch,
mean time, Hest-bank. 6th, The predicted time (by Hoi-
den's Tables) of high water at Liverpool, reduced to mean
time and the meridian of Hest-bank %. 7th, The direction
and force of the wind. 8th, The state of the surface of the
sea.

f By Reflection, (see page 267 for Dip, &c.)

\ The latitude of Liverpool is 53° 24' 40" north, and its longitude
2° 58' 55" west.

Mr. J. Nixon on the Tides in the Bay of Morecambe. 277

1832.
July 7.

9.
10.

11.

12.
13.

14

16.
17.
18.

19.
21.

23.

24.
25.

26.

27-

30.

31.

Aug. 1.

2.

4-

6.

7.

1829.

Sept. 14-

15.

16.

1830.

Oct. 13.

14.

15-

16.

19.

20.

Div.
9*

4
3
3

Ft. In

28 3f

26 3

•26

Hest-
bank.

6M8U

7 27

8 51

9 44

0*A.M.
0 P.M.
0 A.M.
0 A.M.

6M5°

7 23

8 46

9 39

Liver-
pool.

10 30 0 a.m. 10 24

25 9

25 10

25 6

26 3

27 0

28 0

29 7
28 4

28 6

27 10

26 4

24 9

23 6

22 6t

23 5

25 0

26 5

29 4

30 0
29 9

3 U

1

20 7

20 2

21 5

27 8

26 6

25 3

24 8

24 0

23 6

6 30 a.m. 11 0
42 30 a.m. 11 36

0 19 0 P.M.

27 Op.

2 30 p.

42 Op.

24 Op.

12 30 p

56 0 a

0 12

1 18

1 52

2 31

m. 3 12

m.I 4 59
m.! 6 41

7 37 30 a.m.

5 0 A.M.
8 30 A.M.

7 0 A.M.

2 15 A.

28 Op.
17 Op.

7 Op.

54 45 p.

52 0 p.

39 Oa.

49 45 a,

11 30 0 a.m.

0 15 0 P.M.

1 10 0 P.M

9 35
10 10

10 45

11 21

0 49

1 16

0 A.M.
0 A.M.
0 A.M.
0 A.M.
0 P.M.
0 P.M.

7 22

7 49

8 52

9 50

10 45
1 10

1 58

2 48

3 35
5 31

7 17

8 27

6M3"

7 19

8 54

9 43

10 26

1 3
11 36

0 11

1 18

1 51

2 29

3 9

4 54

6 39

7 15

7 49

8 55

9 53

10 45
1 10

1 57

2 41

3 28

5 17

7 6

8 19

Wind.

E. ; very little.

S.W. ?

S.W. ; strong.

W.S.W.; gentle

W. ; strong;

w.s.w.

stronger.

W.S.W;

W. gentle. J
N. by E. ; little.
fN.;W.N.W.;1
< W. ; rather ^
[ strong ....J
/W.S.W.; 1
[W.; blustryj
W.byS.;blustry.

W.N.W. ; 1
strong and V

steady J

W. ; gentle

N.N.E.; gentle.
W. by N.; gentle,
f N.W.; ]
4 W.N.W.; V
[raiher strong. J

W. ; calm

N.VV. ; calm

J"S.E.;S.W.;~I
1 gentle.. ..J
N.E.;W.;calm.

W. ; slight

N. ; gentle

J E. by S.; \
1 rather strong. J
E. by N. ; gentle.
W. ; calm. ......

W. ; calm

W. ; slight

Sea.

N.N.W

W.; brisk

N.N.E.: calm.

S.E.;calm

S.E. ; slight ....

S.E.; calm

? ; calm

S.S.E. ; slight...
S. ; very strong.

Ripple; smooth.
Rough; calmer.
IWaves great.
' Rather rough.

Do.

Do.

Nearly smooth.

Calm ; rather
rough.

Very rough.
Do.

Waves great.

Slight swell.
Nearly smooth.
Do.

Rather rough.

Smooth.
Smooth ; ripple.

Slight ripple.

Nearly smooth.
Smooth.
Do.

Do.

Rather rough.
Smooth.

Do.
Gentle ripple.

Smooth.
Ripple.
Smooth.

Do.

Do.

Do.

Do.
Rather rough.
Very rough.

t These numbers plus 30*2 feet will give the height of the Lancaster
canal above the tides at high water.

\ The preceding tide would be about 21 feet 6 inches below the top of
the pole.

278 Mr. J. Barton on the Influence of high and low Prices

N. B. The moon's phases were,
New. June 28th, at 6h50ra a.m.
Full. July 12th, 10 49 p.m.
New. July 27th, 1 50 p.m.

Full. Aug. 11th, 2 21 p.m.

Chapel Allerton, near Leeds,
July 24, 1834.

Hest-bank, mean time.

John Nixon.

XXXIX. On the Influence of high and low Prices on the

Rate of Mortality. By John Barton, Esq.*
IN a pamphlet which I published rather more than twelve
■*- months agofj I stated at considerable length the results
of an investigation into the influence of high and low prices
on the condition of the people, as evidenced by the rate of
mortality in the kingdom at large, as well as in our agricul-
tural and manufacturing districts separately. These results
were deduced from a comparison of the number of burials in
the population returns with the price of wheat in each year,
from 1780, the commencement of these returns, down to
1 820, the returns of the succeeding years not being at that time
printed. The subsequent completion of the work enables me
now to state the results of fifty years' experience in this matter.
At the same time I shall be glad to take the opportunity of
saying a few words on an objection which has been urged
against my conclusions by a writer in the Edinburgh Re-
view.

The general result of my inquiry respecting the influence
of the price of corn on the rate of mortality in the kingdom
at large will be seen in the following statement :

Price of Wheat per Win-

Average Burials yearly

chester Quarter reduced

on each Million of

to Bullion Value.

Population.

Under 505.

22-455

505. to 60

20-175

60 to 70

19-778

70 to 80

19-291

80 to 90

18-257

90 to 100

18-117

above 1 00

22-350

* Communicated by the Author.

f Entitled, " An Inquiry into the Expediency of the existing Restrictions
on the Importation of Foreign Corn."

on the Rate of Mortality. 279

From a comparison of these numbers, I inferred,

" 1st, That the extremes of high and low prices are both
unfavourable to the comfort and health of the labouring classes.

" 2nd, That of the intermediate prices, those are most fa-
vourable which approach the higher extreme."

The objection taken by the reviewer to this reasoning, I will
state in his own words.

" Mr. Barton, in the pamphlet placed at the head of this
article, endeavours to prove that a high price of corn di-
minishes mortality ; and in favour of this singular opinion he
produces tables of burials, prices, &c, from 1780. But, what-
ever this gentleman may think, it does not necessarily follow,
that because two circumstances are consentaneous, the one is
therefore the cause of the other. The improved condition
and habits of the labouring and middle classes since 1780,
coupled with the extirpation of the small-pox, and other im-
provements in medical science, have occasioned a diminution
in the rate of mortality, which has more than balanced the
contrary influence of the increased price of corn. Mr. Barton
would have been quite as logical, and quite as correct, had
he ascribed the diminished mortality to the increase in the
number of steam-engines, or to the more general employment
of children in factories." — No. 118. p. 306.

Does the reviewer mean, I would ask, to assert, that the
price of corn has been progressively and uniformly rising
since 1780, and the rate of mortality progressively and uni-
formly decreasing during the same period ? If not, I do not
see the force of his reasoning. If he does, a simple statement
of figures may show how widely he is mistaken.

Periods. Average Bullion Price of Wheat. Rate of Mortality*.

1801—1810 76s.9d 1 in 46*4

1811—1820 75s.ld. 1 in 52-7

1821—1830 575.6c? 1 in 51.

It is true, as the reviewer observes, that the mere consen-
taneous occurrence of two events does not afford any proof,
scarcely a presumption, that any connexion exists between
them. If, on throwing a die, it falls with the face marked six
uppermost, I have no reason to suppose it loaded. But if, on
throwing it many times in succession, the same face invariably
presents itself, a very strong presumption arises that the die
is operated upon by some secret bias. In like manner, if the
irregular fluctuations in the price of corn are found so to fit

* Population Returns of 1831, vol. iii. p. 489.

280 Mr. J. Barton on the hifluence of high and low Prices

and dovetail into the irregular fluctuations of the rate of mor-
tality, that the results, when collected and arranged, exhibit
all the uniformity of a permanent law of nature, will any per-
son of competent judgement assert that the coincidence is ac-
cidental ?

As far as the objections of the reviewer are concerned, I
might, I think, content myself with these observations ; but as
it is a matter of considerable importance and curiosity, not
merely to determine in general terms whether low prices
exercise an unfavourable influence on human life, but to ob-
tain a measure of the quantum of that unfavourable influence,
I have sought for the best means of eliminating the circum-
stances alluded to by the reviewer, so as to present a correct
statement of the influence of the price of corn on the rate of
mortality, freed from all disturbing causes. The most likely
method of accomplishing this purpose seems to be to select for
the basis of our calculation a period such, that on dividing it
into two equal portions, the average price during each of these
portions shall be as nearly equaUas circumstances admit.
Thus, if we select for this purpose the forty years from 1791
to 1830, we shall have

The average bullion price of "I =

wheat from J

Thesamefrom 1811 to 1830 = 66s. 3d.*

If now we suppose a progressive and uniform improvement
in medical science and in the habits of the people to have
taken place during these forty years, it is evident that a nearly
equal proportion of the influence of these favourable circum-
stances will fall on years of high price and on years of low
price, since these years are so equally distributed through
the two periods as to give for the average of the first twenty
years, within a trifle, the same sum as for the average of the
last twenty years.

The following Table contains the results of that calcula-
tion:

If we exclude the years of scarcity, 1795, 1800, and 1801, we have

The average of the first nineteen years 65*. Od.

The same of the last eighteen years 65s. 9d.

on the Rate of Mortality.

281

1791

1792

1793

1794

1795

1796

1797

1798

1799

1800

1801

180-2

1 803

I804

I805

1806

1807

1808

I8O9

1810

1811

1812

1813

I8I4

1815

1816

I8I7

1818

1819

1820

1821

1822

1823

1824

1825

1826

1827

182&

1829

1830

Female
Popula-
tion.

4,140,000
4,190,000
4,245,000
4,292,000
4,336,000
4,374,000
4,421,000
4,475,000
4,532,000
4,587,000
4,628,000
4,659,000
4,713,000
4,777,000
4,853,000
4,928,000
5,003,000
5,074,000
5,142,000
5,218,000
5,283,000
5,364,000
5,442,000
5,529,000
5,608,000
5,708,000
5,794,000
5,886,000
5,970,000
6,053,000
6,144,000
6,247,000

Burials

of
Females.

6,355,000
6,453,000
6,550,000
6,644,000,
6,734,000
6,829,000
6,933,000
7,026,000

92,668

94,794

101,699

98,933

104,747

95,426

95,825

93,765

94,348

102,909

103,082

100,385

101,269

89,639

90,154

91,163

97,855

98,149

93,577

103,277

93,572

94,445

92,751

102,878

97,966

102,005

98,229

105,900

106,815

104,020

104,870

109,116

117,737

120,047

125,291

132,061

122,880

125,318

129,705

124,777

Burials on each Million of Population when the
Price of Wheat is

under50s 50s.to60s. QOs.tolOs. 10s.to80s. 80$.to90*. 90*.tol00*. above 100«,

22,380
22,620
23,960

20,950

17,460

23,050
21,670

21,490

18,760

18,610
17,470

17,070
18,5*20

19,880
18,250
18,350

Average of forty years 21,474i 19,375

20,820
21,550

19,560

24,160
21,820

17,180

18,600
19,130

8,710
17,760

18,500
19,340

17,7*10
17,040

17,*870

17,890

18,580

18,200

17,990

19,790
17,610

16,950

22,430
22,270

19,163:19,292 18,257 18,116

Wheat per

Quarter.

In I In

Paper. Bullion.

S. d,

22,350

50

67
113
118

67
56
60 1
87 10
79 0
73 3
79 0
95 7

106 2
94 6

125 5

108 9
73 11
64 4
75 10
94 9
84
73 0

Imper
56 2

4780<i
42 11
48 11
51 8
74 2
77 1
53 1
48 10
64

104

108
63

44

53
64
68
58
56
60
66
64

80
71
65
54
43
51
62
66
57
55
58
64
62

55
58
85
74
69 1

74
81
97
76 1
96 7
79 8
59 11
54 5
73 9
92 9

Few persons, I believe, on comparing the numbers at the
foot of this Table with the price of corn, will dispute that it
furnishes strong evidence of the tendency of low prices to
abridge human life. But I confess I was startled, on taking

Third Series. Vol. 5. No. 28. Oct. 1834.. 2 O

282 Mr. J. Barton on the hiflnence of high and low Prices

the averages, with the anomaly exhibited by the fourth co-
lumn, which exhibits the rate of mortality in those years when
the price of wheat was between 705. and 80s. per quarter. It
will be seen that the number at the foot of this column, in-
stead of being less than the preceding number, agreeably to
the general rule, is somewhat greater. So invariable were the
results that I had obtained in my former calculations, — so
constantly had I found that every decline of price below 100s.
per quarter is followed by an increase of deaths, that I was
surprised to meet with any exception to this general law. On
a little further examination, however, I discovered that this is
just one of those cases in which the exception serves to con-
firm the rule. The anomaly in question depends entirely on
the peculiar circumstances of the year 1795, which was, in
fact, a year of severe scarcity, as any one may ascertain by
referring to Burke's " Thoughts and Details on Scarcity," or
other contemporary writings. The mortality of this year
ought, therefore, to be classed with the numbers in the last
column, though the average price of wheat did not exceed
74s. 2d. ; since it is evident that all scarcity is relative, and
that the same price which denotes a moderately abundant
crop at one period, may indicate a general failure at another
period. Omitting, therefore, the year 1795, the average num-
ber of burials per million of population, in those years when
the price of wheat fluctuated between 70s. and 80s., is found
to be 18*596, — intermediate between the numbers on either
side, — and the regularity of the results is restored.

It may serve further to elucidate this subject, and to con-
firm the conclusions which I have been endeavouring to esta-
blish, if I show that on dividing the fifty years embraced by
the Population Returns into five equal periods, the general law
above enounced holds good with regard to each of these five
periods separately. The middle price, in every case, will be
found accompanied by a lower rate of mortality than the ex-
treme either of high or of low price. It is scarcely necessary
to observe how powerful must be the influence of the price of
corn on the duration of human life, when it can so far over-
come all the other circumstances affecting the rate of mortality
as invariably to make itself sensibly felt within the short in-
terval of ten years. I am somewhat curious to know whether
the reviewer, after looking over these statements, will still con-
tinue to maintain his opinion that low prices are favourable to
the health and longevity of the people.

on the Rate of Mortality.

283

Year.

Low
Price.

Year.

Middle
Price.

Year.

High
Price.

Year.

Low
Price.

Year.

Middle
Price.

Year.

High
Price.

1780.
1781.
1786.
1787.
1788.

Under46*.
26,650
26,150
23,970
23,670
23,800

1782.
1783.
1784.
1785.
1789.

46*. to 55s.
24,810
24,780
25,560
25,060
23,230

1795.
1796.

Above
555.

Above

70s.

24,170

21,820

1802.
1803.
1804.
1807.

Under70*.
21,550
21,490

18,760
19,570

1805.
1806.
1808.
1809.

70*. to 90*.

18,580
18,500
19,340
18,200

1800.
1801.

Above90*.
22,450
22,270

Average 20,342

18,655

22,360

24,688

Average 24,848

1814.
1815.
1816.
1819.

Under75*.
18,610
17,470
17,870
17,890

1811.
1813.
1817.

1818.

75*. to 95*.
17,710
17,040
16,950
17,990

1810.
1814.

Above95*.
19,790
17,610

1791.
1792.
1793.
1798.

Under 50*.
22,380
22,620
23,950
20,950

1790.
1794.
1797.
1799.

50*. to 70*.
22,940
23,040
21,690
20,820

Averag<

2 22,475

22,122

|22,995

Average 17,960

17,422

18,700

Year.

Low Price.

Year.

Middle Price.

Year.

High Price.

Under 62s.

62s. to 70s.

Above 70s.

1821.

17,070

1820.

17,180

1822.

17,460

1825.

19,130

1823.

18,520

1829.

18,710

1824.

18,600

1830.

17,760

1826.

19,880

1827.

18,250

1828.

18,350

Average

18,304

18,195

Recapitulation.

Periods.

Rate of Mo
Low Price.

rtality at
Middle Price.

Difference in favour of
Middle Price.

1780—1789.
1790—1799.
1800—1809.
1810—1819.
1820—1830.

24,848
22,475
20,342
17,960
18,304

24,688
22,122
18,655
17,422
18,195

160
350
1,687
538
109

Stoughton, May 21, 1834.

2 0 2

284 The Rev. P. Keith on the Internal Structure of Plants.

XL. On the Reappearance o/'Halley's Comet,
XT has generally been considered that this comet will not
A be seen till towards the end of the ensuing year 1835; and
the ephemerides of its place have been computed on this sup-
position. But Sir Thomas Brisbane has recently received a
letter from Mr. Rumker, who says that he thinks it may pos-
sibly be seen with a good telescope as early as December in
the present year ; and he has transmitted an ephemeris, com-
puted from the elements of M. Pontecoulant, which, through
the kindness of Sir Thomas Brisbane, we are here enabled to
present to our readers, and which, perhaps, may be the
means of detecting this singular and remarkable body nearly
a twelvemonth earlier than was expected.

Ephemeris of the

Comet for Mean Noon in

Greenwich.

Logar. of the Comet's

Day of the

Right

Declina-

Distance from the

Passage over

Month.

Ascension.

tion.

*

the Meridian.

Sun.

Earth.

1834.

h m s

o '

h m

Dec. 16.

5 35 10

+ 12 18

0-65740

0-55315

11 546

26.

5 20 52

12 18

0-64780

0-54382

H 47

1835.

Jan. 5.

5 6 32

12 20

0-63787

0-53924

10 10-7

15.

4 53 0

12 26

0-62760

0-53941

9 17*6

25.

4 40 52

12 36

0-61694

0-54357

8 26-0

Feb. 4-

4 30 40

12 43

0-60589

0-55058

7 362

14.

4 22 26

13 7

0-59440

0-55917

6 50-4

22.

4 17 30

13 24

0-58502

0-56681

6 11-8

March 2.

4 13 46

13 43

0-57503

0-57414

5 36-5

10.

4 11 22

14 4

0-56486

0-58115

5 2-4

18.

4 9 26

14 27

0-55432

0-58735

4 28-9

26.

4 9 55

14 51

0-54339

0-59249

3 577

April 3>

4 10 40

15 17

0-53203

0-59633

3 26-8

XLI. On the Internal Structure of Plants, By the Rev.
Patrick Keith, F,L.S,

[Concluded from p. 188.]

Elementary Organs.
QUCH is our analysis of the composite organs, from which
^ it appears that they are all ultimately reducible either to
epidermoid lamina?, or to cells, or to longitudinal fibre ; which
we must consequently regard as being, under one modifica-
tion or other, the ultimate and elementary organs of the whole
fabric of the plant. Are the fibres of plants tubular?

The Rev. P. Keith on the Internal Structure of Plants. 285

If the stem of a plant of Marigold is divided by means of
a transverse section, the divided extremities of the longitu-
dinal fibres, arranged in a circular row immediately within
the bark, will be distinctly perceived, and their tubular struc-
ture demonstrated, by means of the orifices which they pre-
sent, particularly when the stem has begun to wither. The
tubular structure of the longitudinal fibres of woody plants is
not so easily demonstrated. We might infer it, however, from
the force and facility with which the sap ascends to the very
summit of the stem in the spring and summer, and there are
some cases in which we may discern it even with the naked
eye. On the horizontal section of a piece of wood that has
been long exposed to the action of the atmosphere, the ori-
fices of the longitudinal tubes will appear arranged in circu-
lar rows in the direction of the concentric layers. Further,
Hedwig affirms that he observed them on the transverse sec-
tion of a branch of the pear-tree, detached even in the spring,
while the sap was yet flowing *. Hence we may believe that
the longitudinal fibres of plants are, in fact, longitudinal tubes
containing or conveying the alimentary juices. They exhibit
a considerable variety of structure, and have been distributed
by botanists into several distinct species.

We will take them in the order, and under the anatomical
designations introduced or adopted by M. Mirbel, as being
one of the most distinguished of modern phytologists. We
are aware, indeed, that his anatomy of the sap-vessels has
been denounced as fantastical, and his theory of their origin
and functions as absurd; and the anatomy and theory of
Kieser extolled and applauded to the skies, as being of the
most philosophical character f. Yet we confess that we can-
not see the ground whether of this censure, or of this applause.
Whatever may be the value or fate of M. Mirbel's theory on
this subject, his anatomy was a signal step in advance of all
that had preceded it; and if succeeding anatomists have sur-
passed him in accuracy of research, they have been indebted
to his discoveries, or to his errors, for the progress they made.
For the rest, what do we find in the greater part of Kieser's
sap-vessels but the vessels of Mirbel under a different name?
What are we to say of his intercellular canals ; and what are
we to think of him as an inventor of theories, when we are
told that his account of the origin of the cellular tissue sur-
passes in absurdity even that of M. Mirbel J? We have now
a more formidable opponent to the theory and anatomy of

♦ De Fibrcc Vegetabilis Ortu, sect. i.

t Supplement to Encyc. Brit., p. 289. % Ibid. p. 304.

286 The Rev. P. Keith on the Internal Structure qf Plants.

Mirbel than ever Kieser was. It is to the eclaircissemens of
Dutrochet that we are indebted for any new light that has
been lately thrown on the structure of the sap- vessels. Still
we cannot do without Mirbel. We must have him, if it were
but for the sake of refuting him, as the defenders of our faith
must have the books of the infidels.

The vessels of plants are divided by Mirbel, into sap-ves-
sels, and proper vessels. Of the sap-vessels he enumerates
five species, — porous tubes, spiral tubes, false spiral tubes,
mixed tubes, and cellular tubes — les vaisseaux en chapelet. Of
the proper vessels he has but one species, which he calls sim-
ple tubes.

The first species of tubes containing sap are the porous
tubes. They are described by Mirbel as having compara-
tively a considerable width of diameter, and as being pierced
with multitudes of minute holes or pores distributed in parallel
and transverse rows. They abound in woody plants. They
are not continuous from the base to the summit; but they
unite, separate, and unite again, and finally disappear by
changing into cellular tissue. The doctrine of porous tubes was
attacked by the German phytologists with as much hostility as
was that of porous cells. But it met also with some strenuous
defenders ; and even the antiporists themselves were obliged
to admit that the vessels in question are studded with lumin-
ous points, or with little transparent vesicles, arranged as
the pores are said to be ; so that at all events Mirbel's account
is not a fiction, but a mistaking of the character of certain
given appearances. Thus the matter might have been said
to be left in doubt. But as Dutrochet has searched for the
pores of the tubes, as he searched for the pores of the cells,
without being able to find them ; and has, at the same time,
adduced strong reasons for supposing them to be merely small
and minute molecules imbedded in the substance of the mem-
brane that forms the vessels*, we regard the doctrine of porous
tubes as being no longer tenable.

The second species of tubes conducting sap is the spiral
tubes — a name not imposed, but adopted, by Mirbel, as being
long in use. They are fine, transparent, and thread-like sub-
stances, occasionally interspersed with the other tubes of the
plant, but readily distinguished from them by their being
twisted in the form of a corkscrew from right to left as in the
stem of Spearmint ; or from left to right as in the stem of
Fuller's Teasel. Grew and Malpighi, who first discovered
and described them, represented them as resembling in their

* Recherchcs Anatomiques, p. 27-

The Rev. P. Keith on the Internal Structure of Plants. 287

appearance the tracheae of insects, and designated them by that
term, an appellation by which they are still very generally
known.

They do not occur often in the root, or at least they are not
easily detected in it ; yet Kieser is said to have found them in
it in great abundance*. Dutrochet could find none, and de-
nies their existence in the root expressly f. Neither are they
to be found in the branch or stem of woody plants, except in
the annual shoot ; nor in the pith of any plant, except in the
several species of Nepenthes%. But in the stem and branches
of herbaceous plants they are generally to be found without
much difficulty accompanying the longitudinal fibres, and
forming part of the bundles. They are very easily detected
in the foot-stalk, whether of the leaf or flower. The leaf-stalk
of the Artichoke affords a good example, in which they are
not only remarkably large and distinct, but also remarkably
beautiful. They are discoverable also in the leaf itself; more
rarely in the calyx and corolla ; and more rarely still in the
other parts of the flower. Grew and Malpighi found them
both in fruits and seeds. I have myself met with them in the
external umbilicus of the Cherry at a very early period of its
growth, that is, about the time of the falling of its petals, but
not in any other fruits.

Is it certain that the organs now under consideration are
tubes ? In the closely coiled up state in which they exist in
the growing plant they evidently constitute tubes by the union
of their spires. Divide a leaf-stalk of the Artichoke or of the
Elder longitudinally, cutting it partly, and tearing it partly
asunder, and place a portion of it under the microscope. In-
spect the exposed surface carefully and in a strong light, and
it will present to your view bundles of spirals in their coiled
up and united state. Divide a portion of the same leaf-stalk
transversely, cutting it partly and breaking it partly asunder.
Place it under the microscope in a clear and strong light, and
multitudes of spirals, not yet divided, but merely drawn out
and uncoiled, will be found to connect the fractured surfaces ;
and if you stretch them even till they give way, the fragments
will, as if by an elastic and inherent spring, coil themselves up
again nearly as before.

Much has been said with regard to their functions. Some
have believed them to be air-vessels; others, as Mirbel, re-
gard them as being sap-vessels. Dutrochet believes them to
be conductors, not of sap, but of a diaphanous and peculiar
fluid, the product of insolation. This we state, however,
* Suppl. Encyc. Brit., Veg.Anat. f Ly Agent, p. 20.

J Phil. Mag., Oct. 1832, p. 317.

288 The Rev. P. Keith on the Internal Structure of Plants.

merely en passant, as the functions of the several organs of the
plant do not come within the scope of our present inquiry.

The third species of tubes conducting sap is the false spiral
tubes. According to Mirbel they derive their spiral appear-
ance merely from being cut transversely by parallel fissures.
They cannot, like the true spirals, be uncoiled, and are hence
fitly denominated false spirals. They are said to abound in
the Lycopodia and in Ferns, and in the soft parts of the Vine.
But what says Dutrochet? He says that what Mirbel took to
be parallel fissures are merely globules arranged as in the
porous tubes; that the spires may be uncoiled by means of
the long-continued action of nitric acid destroying the bond
of agglutination; and that the vessels in question are, after all,
veritable spirals*.

The fourth species of tubes conducting sap is the mixed
tubes, that is, tubes combining in a single individual two or
more of the foregoing species. Mirbel exemplifies them in
the case of the Flowering Rush ; but Dutrochet says there are
no such vessels as mixed tubes in any plant whatever, unless
you choose to regard as such tubes having some globules ar-
ranged in transverse rows, and some scattered. Yet these
accidental varieties are not enough to constitute species.

The fifth species of tubes conducting sap is the cellular
tubes, that is, tubes composed of a succession of elongated
cells united like those of the cellular tissue. Individually
they may be compared to the stem of the grasses, which is
formed of several internodia separated by transverse dia-
phragms ; and collectively, to a united assemblage of parallel
and collateral reeds. Dutrochet admits the existence of such
vessels, but he designates them by a different name, and finds
them assuming not merely a longitudinal but also a transverse
direction, making part of the medullary rays. Like the cells
out of which they are formed, they are furnished with glo-
bules.

The only species of proper vessels that M. Mirbel describes
is the simple tubes. They are the largest of all vegetable
tubes, and are formed of a thin but entire membrane, without
any perceptible fissure or disruption of continuity. They
abound chiefly in the bark, but are found also in the alburnum
and even in the matured wood. They convey the descending
and elaborated juices. Dutrochet has vessels for this purpose
also, but he does not give them the same name nor structure;
and he has proper vessels likewise, but he does not assign to
them the same function. Hence there is nothing in M. Mir-

* Rccherches Anatomiqucs, sect. i. p. 18.

The Rev. P. Keith on the Internal Structure of Plants. 289

beFs account of the vessels of plants that Dutrochet has not
got something to object to.

But as M. Dutrochet may be thus said to have demolished
the superstructure of M. Mirbel, it was but fair that he should
substitute something in its place. This he has accordingly
done upon the firm and legitimate basis both of observation
and experiment; so that instead of the vessels of Mirbel,
which seem to have been multiplied into too many species,
we have now the following, as exhibited by Dutrochet*.
1st. Globule-bearing tubes, or lymphatics, les vaisseaux corpus-
culifercs. They abound in the wood, and particularly between
the concentric layers of different years. They are studded
with small globules, or molecules, that are imbedded in their
walls, and they conduct the ascending sap. 2dly. Spindle-
shaped tubes, or clostres. They consist of a longitudinal suc-
cession of small tubes, swollen in the middle and pointed at
the extremities, and often divided by transverse diaphragms.
They are destitute of globules. They conduct the cambium,
or descending and elaborated juice, partly through the chan-
nel of the alburnum, but chiefly through that of the bark.
3rdly. Spiral tubes, or tracheae. These Dutrochet describes
as approaching pretty nearly to the true spirals of Mirbel,
with the exception of their being furnished with globules end-
ing in conical spires ; but he assigns to them a different func-
tion, namely, that of conveying to the interior of the plant a
vivifying fluid, the product of insolation. 4thly. Proper ves-
sels, les vaisseaux propres. They are found both in herbaceous
and woody plants. They have a great comparative width of
diameter. They convey the descending and secreted fluids,
such as the milky juice of the Fig or Spurge, and yellow
juice of the Celandine, and differ from the lymphatics chiefly
in being destitute of globules. 5thly. Articulated cellular
tubes. They consist of a series of united cells assuming a
tubular form, sometimes longitudinally, and at other times
transversely, forming the divergent layers. They are regarded
by Dutrochet as an emanation from the pith. They seem to
correspond to the cellular tubes of Mirbel; but in place of
being furnished with pores, we are to regard them as being
furnished with globules.

Thus we have reached and inspected the ultimate and ele-
mentary organs of which the whole fabric of the plant is com-
posed ; and if it is asked of what the elementary organs are
themselves composed, the reply is, they are composed, as
appears from the same analysis, of a thin, colourless, and

* Rccherckes Anatomiques, sect. i.

Third Series. Vol. 5. No. 28. Oct. 1834. 2 P

290 The Rev. P. Keith on the Internal Structure of Plants.

transparent membrane or pellicle, fine as the film of a single
epidermis, in which the eye, aided by the assistance even of
the best glasses, can discover no traces whatever of organiza-
tion ; or if any further analysis is practicable, it is that only
which conducts us to the molecules of modern philosophers.

In the course of the foregoing investigations we have seen
the great variety of modes in which the elementary organs are
grouped, so as to constitute a class, or order, or division.
We have seen that these groupings are constant in the orders
or divisions in which they are found, and that the greater the
complexity of organization, the higher the rank of the plant,
as ascending from the lowly Flag or Fungus, to the tall and
spreading tree. It is upon this ground that we have instituted
our general distribution of plants into Perfect and Imperfect,
with the various intermediate gradations which they exhibit ;
and if the two classes are compared together, the superiority
of the former will be rendered manifest, whether we regard
their external fabric or their internal structure. Perfect
plants are furnished with roots, by which they fix themselves
firmly to a spot and absorb nourishment from the soil. Many
of the imperfect plants are altogether rootless, and live only
by imbibition from the atmosphere, or they are apparently a
mere root, and are lodged wholly in the earth. Perfect plants
are furnished with a stem and branches, giving them elevation,
and expansion, and magnitude. Many of the imperfect plants
are altogether stemless, and are scarcely elevated above the
level of the soil on which they grow. Perfect plants are fur-
nished with leaves and conspicuous flowers, as well as with
conspicuous fruit, giving verdure and odour and beauty to the
forest and to the plain, and filling the land with plenty. Many
of the imperfect plants are destitute of leaves entirely, and al-
most all of them are destitute of conspicuous flowers as well
as of conspicuous fruit, presenting to the beholder nothing
that is showy, nothing that is attractive, nothing that is cal-
culated to delight the eye. Such are the distinctions arising
from the external structure of plants. Their anatomy gives a
similar result. In the highest orders of vegetables you have
the greatest complexity of internal structure, the vascular and
the cellular forms being united, and the caudex composed of
epidermis, bark, wood and pith, exhibiting an intricate plexus
of concentric and divergent layers, cortical as well as ligneous.
In the secondary orders you have less complexity of structure,
the vascular and the cellular forms being indeed united, and
the caudex composed of epidermis, pulp, and interspersed
fibre, but exhibiting no plexus of concentric or divergent
layers, whether cortical or ligneous. In the lowest orders

i

The Rev. P. Keith on the Internal Structure of Plants. 291

you have the least complexity of structure, that is, a structure
simply vascular, the caudex being composed merely of a ho-
mogeneous mass of pulp covered with a fine epidermis.

Yet the plants called imperfect, though occupying the lowest
grade in the scale of terrestrial life, are precisely what they
ought to be, and are altogether indispensable to the integrity
of the vegetable kingdom. They are, as it were, the founda-
tion on which the superstructure of a more luxuriant vegeta-
tion is raised, whether we regard them as having made part
of a former world, or as they now exist. They sow their seeds
spontaneously. They germinate where no other plants could
live. They grow up, and come to maturity, and perish where
they grow, and thus form in the process of years a soil fit for
the habitat of plants of a nobler order. Hence, though they
are devoid of fair forms, they are by no means devoid of uti-
lity. Without them we do not know that the more perfect
lants could exist : and what would the surface of this earth
e if stript of its vegetation ? — a mere expanse of desert, or of
bare and flinty rock ; or, as in the deluge of old, a vast and
trackless deep, rolling in unrestrained majesty, and rendering
the encompassed globe totally unfit for the habitation of men
or of animals; a blank, if we may presume to say so, in the
creation of God !

Quaque fuit tellus, illic et pontus et aer.
Sic erat instabilis tellus, innabilis unda,
Lucis egens aer. — Ovid, Met., i. 15.

But look at its beautifully diversified surface under the mo-
dification of hill and dale, mountain and valley, river, lake,
ocean ; the hills covered with verdure, the valleys abounding
in corn, and in the fairest forms of vegetable being; the
mountains skirted with the sturdy oak, the noble cedar, or
the lofty palm; the rivers carrying health and fertility along
with them in their winding course, and an ocean wafting the
tall and stately bark, richly laden with merchandize, to the
remotest shores of the habitable globe, and enabling the ad-
venturous mariner to carry back in return the wealth or the
superfluities of distant regions.

Vela danius, vastumque, cava trabe, currimus aequor.

Mneidy iii. 191.

Look at these providential arrangements resulting from the
bounty of a kind Creator, and you have a world replenished
with everything that is needful to the support of animal life,
and paradise fitted for the reception of man !

Ashford, Jan. 17, 1834. P. Keith.

2 P2

[ 292 ]
XL 1 1. Proceedings of Learned Societies.

GEOLOGICAL SOCIETY.
[Continued from p. 230.]

(Abstract of Mr. Murchisons Paper " On certain Trap Rocks in the
Counties of Salop, Montgomery, fyc.,'' read May 21st, — continued.)

Brecknockshire. — A RIDGE of trap rock of about three miles in
**■ length and half a mile in width, extends from
the stream of Nanteinon on the north-east to the right bank of the
Yrfon near Llanwrtyd on the south-west. The gorge, in which the
little river Cerdin flows, separates this ridge into two mountains,
Gaer Civm and Carn Dwad.

The predominant character of the trap is porphyritic, including
greenstones, compact felspar rocks, &c. Some of the porphyry
is columnar. This nucleus is irregularly coated over with a thin
and broken covering of highly altered grauwacke schist, which is
frequently in the state of Lydian stone, from beneath the dislocated
beds of which bosses of trap protrude. Other varieties of altered
rock in contorted positions are seen on the flanks of the ridge, in
some of which are crystals of iron pyrites and small portions of car-
buret of iron.

Absurd trials for coal, similar to those previously described, have
been made on the sides of these hills. The mineral source of Llan-
wrtyd issues from the pyritized schist on the banks of the Yrfon,
and it was from a conviction that the phenomena in this case might
be due to volcanic action similar to that noticed in the cases near
Llandrindod and Builth, that the author was induced to examine
this remote district. The result justified his anticipations, and led
him to the discovery of this intrusive ridge.

Caermarthenshire. — The only example of trap rock in the large
portion of Caermarthenshire which has been examined, was detected
last summer in the small rocky knoll of Blaen-Dyffrin-garn, about
three miles south-east of Llangadock. This trap is more or less
porphyritic, from which state it passes into a rock having a base of
compact felspar in parts containing concretions and disseminated
green earth. It throws off strata of sandstone of about the same
age as those found on the sides of the Wrekin and Caer Caradoc,
and the phenomena resulting from the contact are identical with
those of Shropshire, the sandstone being converted into a hard and
granular quartz rock, having a conchoidal fracture.

This line of altered rocks runs precisely parallel to the strike of
the strata of the grauwacke series, and is traceable for miles to the
south-west, the most prominent elevation of the quartz rocks being
Cairn-goch, formerly a Roman camp.

Small metalliferous veins, chiefly of lead, have been found along
this line of eruptive elevation, particularly on the right bank of the
river Sowdde.

The only lead mines now in work in Caermarthenshire are at
Nant y Moen, seven miles north of Llandovery, and it is highly
worthy of remark, that although these are situated so far to the

Geological Society. 293

westward of the range of fossiliferous grauwacke, their relations are
analogous to those of the Shelve district, in presenting on one flank
a mountainous wall of highly altered conglomerate and quartz rock
running from north-cast to south-west, which forms the chief rider
to those veins, as in the case of the Stiper Stones in Shropshire.

II. Malvern and Abberley Hills. — The author highly commends
the description of the Malvern Hills published by Mr. Horner in the
Geological Transactions*, and refers to it for a faithful account of
their mineralogical structure. The present memoir dwells more at
length on the effects produced by these sienitic rocks upon the
grauwacke strata among which they have been protruded, and which
have been altered into chloritic and micaceous schists, highly indu-
rated grits, &c; whilst others, although unaltered, have been thrown
into an inverted position, as pointed out upon a former occasion-}-.

The author points out the existence of certain bosses of sienite
and greenstone in Cowley park to the north of the main chain.
He then proceeds to indicate the various points at which masses of
eruptive rock hitherto unnoticed appear at the surface in the north-
ern prolongation of the direction of these hills, and connect the
Malvern with the Abberley Hills. These are the hills of Berrow,
Woodbury and Abberley. They are all of rounded forms, and so
covered with vegetation that their structure can only be ascertained
from the knobs of rock which occasionally protrude. They chiefly
consist of concretionary, compact felspar, sometimes containing
crystals of common felspar. That they have, however, a mineral
nucleus similar to that of the Malverns, is to be inferred from two
observations: 1st. The discovery at the north end of Berrow Hill of
a small boss of rock having quite a granitoid character, being made
up of compact felspar, quartz and silvery mica, and therefore undi-
stinguishable from a sienite of the Malverns. 2ndly. The discovery
of a remarkable dyke at Brockhill, on the right bank of the river
Teme, Worcestershire. This dyke is evidently a spur from the trap-
pean hills of Woodbury and Abberley, from the first of which it is
distant only 1J mile, being thrown out in a direction from east to
west. The dyke cuts through the old red sandstone, and consists
chiefly of sienite or sienitic greenstone perfectly analogous to many
varieties of the Malvern Hills. It is in great part columnar, the ends
of the columns being at right angles to the walls of the dyke. The
6tratain contact with the trap are much hardened; the mica appears
to be driven off from the sandstone, the colour of which is changed
to a dingy dark purple ; and the associated marls and cornstone are
converted into hard amygdaloids, with veins of carbonate of lime,
crystals of iron pyrites, &c. &c.

Another dyke of trap traversing the old red sandstone, which is
marked in Mr. Greenough's map, occurs at Bartestreenear Hereford.
It is a basaltic greenstone, with olivine, and the strata in contact are
affected similarly to those of Brockhill near Abberley.

III. Trap Rocks penetrating the Coal Measures.

* Geol. Trans., 1st Series, vol. i. p. 281.

t Proceedings, vol. ii. p. 18 : and Lond. and Edin. Phil. Mag. and Jouni.,
Third Series, vol. iv., May 1834, p. 375.

29 i Geological Society.

. Clee hills. — The basalt of the Titterstone and Brown Clee Hills
having been described, the author only refers to his former com-
munications for the purpose of stating, that Mr. Lewis of Knowlbury
has proved the existence of an eruptive wall of basalt which cuts off
the coal of the Treen pits, precisely in the linear direction of that
which has been called the Jewstone (basaltic) fault. The coal in the
proximity of the basalt is much altered and of no value.

Wenlock and Coalbrook Dale. — The greenstones and amygdaloids
which rise up at various points through the carboniferous limestone
and coal measures of this tract, are marked by the author on the
Ordnance map, but he suggests that their chief interest will be ap-
parent when the survey of all the dislocations of these coal fields by
Mr. Prestwich, shall have been completed.

Kinlet. — This is rather a peculiar trap, being a greenstone in which
white spots of granular felspar are dotted through a base of dark
hornblende. It rises into knolls, protruding through the coal
measures, flanked by old red sandstone.

Arley and Shatterford. — This dyke of trap has been described
by the Rev. J. Yates*, to which account the author adds some de-
tails respecting its structure, and the beds of coal, sandstone and
shale upon its sides ; the chief additional fact being, that the red
sandstone which immediately surrounds this narrow zone of coal
measures is not the new red sandstone of Bewdley and Kiddermin-
ster as formerly supposed, but a girdle of old red sandstone, with
beds of cornstone, which is distinctly separated from the new red
sandstone and folds round this peninsulated carboniferous tract.

Conclusion. — From the natural phenomena described in the pre-
ceding pages it appears,

1. That volcanic agency satisfactorily accounts for the appear-
ance of all the varieties of trap rock which are associated with the
grauwacke series, the old red sandstone, and carboniferous strata
in the country under review.

2. That from the imperceptible passages which take place be-
tween the different varieties of these trap rocks it is difficult, from
mere lithological characters, to assign a separate age to each.

3. That as some of the porphyritic and felspathic rocks, alter-
nate conformably with strata of marine origin containing organic
remains of a very early period, and as some of the layers in which
such remains are imbedded have a base of true volcanic matter, the
date of the origin of this class of rock is thereby fixed.

4. That these conformable alternations of trap and marine sedi-
ment establish a direct analogy between their mode of production
and those replications of volcanic ejections and marine deposit
which are now going on beneath the present seas ; whilst they fur-
ther explain the manner by which, in times of the highest geological
antiquity, the porphyry slates were arranged in parallel laminae with
the sedimentary accumulations of that age.

5. That the existence of certain strata containing organic re-
mains, yet possessing a matrix, composed in great measure of the
same materials as the adjacent ridges of trap rock, has strengthened

* Geol. Trans., New Series, vol. ii. p. 249.

Geological Society. 295

the inference that some of the ebullitions of these submarine vol-
canos were contemporaneous with the period in which these ani-
mals lived and died, the finer volcanic ejections having, it is pre-
sumed, led to the formation of the volcanic sandstone.

6. That subsequent to these contemporaneous classes, other trap
rocks have been forcibly intruded, amidst deposits of all ages, from
the oldest grauwacke up to the strata of the coal measures, pro-
ducing great derangement, fracture, and alteration in the beds which
they penetrate, exhibiting, at the points of contact, siliceous schists,
porcellanite, many crystallized substances, veins, quartz rock, &c.

7. Special attention is invited to that change by which sand-
stone has been converted into quartz rock, because it appears to
explain how the so-called^mwary quartz rock may have been formed.

8. It is inferred that all the metalliferous veins in the country
described are due to the presence of the contiguous trap rocks, and
that therefore this inquiry has amply corroborated the theoretical
speculations of M. Necker*.

June 4. — A paper was first read, entitled, " Observations on
the Strata penetrated in sinking a Well at Diss, in Norfolk," by
John Taylor, Esq., Treas. G. S.

The well alluded to in this communication affords the only details,
hitherto made public, of the thickness and character of the chalk
in that part of Norfolk in which Diss is situated.

The well was sunk by Mr. Thomas Lombe Taylor, and the fol-
lowing list gives the order and thickness of the beds :

Clay 50 feet.

Sand 50 —

Chalk, without flints, soft and of a marly nature 100 —

Chalk, with flints in layers of single stones, distant "I „.„
about a yard from each other j

Grey chalk, with an occasional layer of white chalk, 1 _
and free from flints J

Light bright blue chalk, approaching to clay, with 1 ~0
white chalk stones J

Sand 5 —

615
On penetrating the light blue chalk, the tools sunk rapidly for
about 5 feet, and the water rose to within 47 feet of the surface, at
which height it is stated to have continued.

A paper, entitled, 4< Observations on a Well dug at Lower
Heath, on the South Side of Hampstead," by Nathaniel Wetherell,
Esq., F.G.S., was next read.

The strata penetrated in making this well are stated by Mr.
Wetherell to be as follows :

London clay 285 feet.

Rock : 5 —

Plastic clay 40 —

330

* Proceedings, vol. i. p. 392 : and Lond. and Edin. Phil. Mag. and Journ.,
Third Series, vol. i., September 1832, p. 225.

296 Geological Society.

The London clay, for the first thirty feet, was of a loose texture,
reddish brown colour, and contained a good deal of iron pyrites
and selenite : for the next hundred and seventy feet it varied in
colour from blue to dark brown, and contained many septaria; and
the lower part was very sandy. At the depth of 260 feet a i'ew
fruits and seeds were procured, — the former resembling those
found at Sheppey, and the latter those found at Highgate ; but
between 265 and 285 feet the clay abounded with vegetable re-
mains. A classed list is given of the fossils obtained by the author;
and among those not previously noticed, he mentions the remains of
Asterias, a Pentacrinite, six species of bivalves, and two small,
straight, tubular bodies, one round, the other square, having an in-
ternal radiated structure like that of a Belemnite, but without a
central cavity.

The rock between the London and plastic clays was full of green
particles, and contained numerous rounded flint-pebbles. The
fossils obtained from it were chalky and friable, and among them
the author found Mya intermedia and Natica glaucinoides, shells
characteristic of the Bognor rock.

The plastic clay presented its usual mottled appearance, but no
organic remains were noticed in it.

At the depth of 330 feet a bed of sand, containing small flint-
pebbles, occurred, and the water gradually rose from it to within
200 feet of the surface.

A letter was afterwards read from Sir Philip Grey Egerton, Bart.
F.G.S.to the Rev. Prof. Buckland, D.D., F.G.S., "On the Ossiferous
Caves of the Hartz and Franconia."

This letter contains a detailed enumeration of the remains found
by Sir Philip Egerton and Viscount Cole in the caves of Gailen-
ruth, Kiihloch, Scharzfeld, and Baumanns Hohle. In communi-
cating these results, the author states that he has made the list as
complete as possible, as from the extreme strictness with which the
Miiggendorf caves are now guarded, it is not probable that any
large collection of bones will again find its way to this country.
With respect to the caves of Kiihloch and Rabenstein, he states, that
the account which he gave in 1829 of their destruction *, has been
fully verified by Lord Cole, who visited them last year j but in con-
sequence of the absence of the Baron of Rabenstein at the time
of their destruction, the author acquits him of having been impli-
cated in the transaction -, and adds, that this nobleman has proved
himself a strenuous friend and patron of science, by the care with
which he protects the newly-discovered cave of Rabenstein from
depredation.

The author states that he found recent bones of pigs, birds, dogs,
foxes, and ruminantia, in every cave which he examined ; frag-
ments of rude pottery in those of Scharzfeld, Baumanns Hohle,
Gailenruth, and Zahnloch ; and old coins and iron household
implements of most ancient and uncouth forms in that of Raben-
stein. In the Gailenruth cave he did not find one bone gnawed by

* Phil. Mag. and Annals, N.S., vol. vi. p. 92, 1829 ; and Quarterly Journal
of Science, vol. vi. p. 213, 1829.

Geological Society. 297

hyenas, but numerous bones of bears marked with short scratches,
the effects, he conceives, of their having been the playthings of
young bears; an idea first suggested to him by observing the
amusement a ball of wood affords a bear in confinement.

Of the genus Ursus, Sir Philip Egerton states that he had found
among the remains procured in the Gailenruth cave, two bones
of the carpus, one of the metacarpus, one of the metatarsus, and
part of the sternum; all required to complete Cuvier's account of
the osteology of the animal; that in the collection from the same
cave, he had found the large incisor of the right side of nearly
ninety bears, and of all ages, from the cutting-tooth to the worn-
down stump ; that he had not a single humerus out of the many
procured from various localities, with the perforation at the condyle
for the cubital artery ; and that out of 36 specimens in his collec-
tion, besides a greater number in Viscount Cole's, he had not no-
ticed one containing the least trace of the small anterior false
molar.

Sir Philip Egerton then gives a detailed list of every bone pro-
cured by himself and Lord Cole. This list it is impossible to give
in an abstract j but it may be stated that the bones obtained from
the cave of Gailenruth belong to Felis Canis, Canis Vulpes, Hyaena
and Gulo j those from Kiihloch to Hyaena, Canis Vulpes and Rhino-
ceros ; those from Scharzfeld to Felis and Canis ; and those from
Baumanns Hohle to Felis.

A letter was also read from Hugh E. Strickland, Esq. to G. B.
Greenough, Esq., P.G.S., " On the Occurrence of Freshwater
Shells, of existing Species, beneath the Gravel near Cropthorne, in
Worcestershire."

In a former letter, dated September 28th, 1833, Mr. Strickland
stated that he had found in a gravel-pit near Cropthorne, fresh-
water shells of existing species, but that the circumstances under
which he had noticed them induced him to hesitate in assigning
them to the age of the gravel. The surveyor of the roads having,
however, at the request of the Worcestershire Natural History So-
ciety, opened a new pit, Mr. Strickland is enabled in this letter to
state, that the same species of shells had been found under hori-
zontal beds of gravel and sand, which presented no sign of having
been disturbed since their deposition. He also states that the re-
mains of the hippopotamus, deer, and he believes ox, had been
found in considerable abundance in the same pit.

A notice " On the Action of High Pressure Steam on Glass and
other Siliceous Compounds," by Prof. Turner, M.D., Sec. G.S.,
was then read.

An opportunity having presented itself to the author, of includ-
ing substances in a high pressure steam-boiler, he took advan-
tage of it to try the effect which would be produced on glass;
and he accordingly encased in wire gauze some specimens of plate-
and window-glass, and suspended them from the top of the boiler,
so that they were surrounded by steam whenever the boiler was in
action. They were kept in this situation for four months, during

Third Series. Vol. 5. No. 28. Oct. 1834. 2 Q

298 Limuvan Society.

which time the boiler was commonly in action ten hours daily, ex-
cept Sundays, its temperature being then at 300° Fahr. On open-
ing the boiler at the end of the time specified, all the pieces of
glass were found to have been more or less decomposed; and the
plate-glass in particular, which is a glass of silex and soda, was far
advanced in decomposition. Flat pieces, £th of an inch thick,
were in some parts decomposed through their whole substance ;
while in others a layer of unchanged glass was found in the middle,
covered on each side with a stratum of opaque white siliceous
earth, having the appearance of chalk.

The author referred these changes to the influence of water on
the alkaline matter of the glass. The white earthy portions were
found to be entirely free from alkaline matter, which had been dis-
solved and removed by the water which condensed upon the glass
at the successive heating and cooling of the boiler, or which may
have been thrown upon it by splashing during ebullition. But the
author considered that the actual loss was not due to the extrac-
tion of alkaline matter only, but that the silex of the glass had in
some measure been dissolved along with the alkali. This was
proved to have been the case by the apertures of the gauze en-
velope being filled up at the most depending parts by a siliceous
incrustation, where also a stalactitic deposit of silica, about \\ inch
long, had formed.

A piece of window-glass included at the same time with the
plate-glass, was also in a decomposing state, but in a much lower
degree. A piece of rock-crystal confined in the boiler at the same
time was wholly unchanged.

The author adduced these facts as illustrative of the action of
water at high pressures on felspathic and other rocks containing
alkaline matters.

LINN^lAN SOCIETY.

April 15. — The reading was commenced of a paper containing
" Observations on some species of native Mammalia, Birds, and
Fishes, including additions to the British Fauna." By William
Thompson, Esq., V.P. Belfast Nat. Hist. Society.

The author commenced by stating, that a perusal of the Rev.
Mr. Jenyns's paper, entitled " Some Observations on the Common
Bat of Pennant, with an attempt to prove its identity with the Pi-
pistrelle of French authors," (Linn. Trans., vol. xvi.) induced him to
examine specimens of the common bat of the North of Ireland, which
hitherto, like that of England up to the period of Mr. Jenyns's paper,
has been considered the Vesperlilio murium of Linnaeus, as well as
of recent continental authors.

This examination led to the same conclusion as that of Mr.
Jenyns, the common bat of Ireland proving identical with that of
England, and consequently with the V. pipistrellus of the Con-
tinent.

Observations on the habits, &c, of this species, when at large and
in captivity, were also given in detail, and were followed by some

Linncean Society. 299

remarks on the Long-eared Bat (Plecotus auritus) as observed in
Ireland.

The occurrence of the Larus Sabini in Ireland on two occasions
was next adverted to. Of this bird two specimens only had pre-
viously been recorded as met with in the eastern hemisphere, both
of which were obtained by Captain Sabine at Spitzbergen. The
specimens which formed the subject of the present paper were
rendered peculiarly interesting from being in the plumage of the
first year, in which state the Larus Sabini had not before come
under the inspection of the naturalist. The appearance presented
by the species at this age was described with great minuteness, and
also the differential characters by which it may at all ages be di-
stinguished from its congener the Larus minutus.

The specimens described are contained in the Museums of the
Natural History Society of Belfast and the Royal Society of Dublin.

From the examination of a specimen of the Cygnus Betvickii,
killed in the North of Ireland, and preserved in the Belfast Museum,
the author stated that he was led to discover that some of the cha-
racters by which this species has hitherto been distinguished are
erroneous.

The principal character pointed out as such was the number of
rectrices, or tail-feathers, which are described in the Linn. Trans,
(vol. xvi.p. 445, et ££9.), Ill us. of Orn. (Part 6), Illus. of Brit. Orn., &c,
to be 18, though they are in reality 20. The correctness of the
view respecting this and the other characters thus dwelt upon was
subsequently confirmed from an inspection of two living birds, which
have been since Feb. 1830 in the possession of William Sinclaire,
Esq., of the Falls, near Belfast.

Observations on the disposition, habits, &c, of these individuals
were also added.

Mr. Thompson embraced this opportunity of exhibiting a specimen
of the Potamogelon prcelongus of lleichenbach, with which he had
been favoured by William Henry Harvey, Esq., of Limerick, who
had the satisfaction of discovering the plant last autumn in the river
Shannon, and thereby making a very desirable addition to the
British Flora.

May 6. — The reading of Mr. Thompson's paper was resumed and
concluded.

The Three-spined Stickleback of the North of Ireland was dwelt
upon at considerable length, and the differential characters between it
and the three English species, as described by Mr. Yarrell (Mag. of
Nat. Hist., vol. iii.) pointed out. From all of these it was stated to be
distinct, but seemingly identical with the Gasterosteus brachycentrus
of the Histoire Naturelle des Poissons of C uvier and Valenciennes, (torn,
iv. p. 499. pi. 98.) a species there published as new, and mentioned
as having been obtained by M. Savigny from the brooks of Tuscany.

The discrepancy between C uvier (Regne Animal, 2nd edit.) and
British authors relative to the Gasterosteus pungitius of Linnaeus
was next noticed.

It was remarked of the Gobius niger from specimens taken in the

20.2

300 Linncean Society.

North of Ireland, (on the shores of which country the species has
not before been recorded as met with,) that the fish so named by
Donovan, with which these were identical, is distinct from the G.
niger of Pennant, and as such ranks as a third species of Gobius
to the British Fauna, two species only having yet a place in it.

The CyclopterusMontagui (Don.), which stands recorded as having
been taken only on the southern coast of England, and there but
by its discoverer, was next introduced, from the circumstance of a
specimen occurring to the author on the coast of the county of
Down in December 1833. The difference, consisting chiefly in
colour and markings between this fish (which was mature) and Col.
Montagu's as described in the Wern. Mem. (vol. i. p. 92.), was pointed
out.

Specimens of all the species treated of in this paper, with the
exception of the Cygnus Bewickii, were exhibited.

Mr. Thompson further announced the following species of land
and freshwater shells to be indigenous to Ireland, though they have
not been recorded as such. They do not appear at least in any of
the three published catalogues of the shells of that country, nor is
he aware of their being incidentally noticed elsewhere.

They were brought forward on this occasion preparatory to a
general catalogue of the land and freshwater shells of Ireland, with
observations on the relative abundance and scarcity of the species,
their geographical distribution, &c, which Mr.T. hopes to lay before
the Society early in the ensuing year.

Pisidium nitidum, Jenyns. P. pidchellum , J enyns. Limacella Par-
ma, Lister. Testacellus Scutulum, Sowerby. Vitrina Drapamaldi,
Jeffreys. — Helix hortensis, Montagu. This species and the Helix as-
persa do not both appear in any catalogue of Irish shells. Capt. Brown
enumerates the H. hortensis in his " Irish Testacea," but his re-
ference to Donovan (t. 131.) makes it evident that it is the H. as-
persa of Montagu, which he brings forward under the name of hor-
tensis.— H. hispida. In the "Irish Testacea" the Helix hispida is
described to be that of Montagu, and of Donovan also ; but as the
same name is applied to two different species by these authors, and
as one species only has yet been recognised as found in Ireland, I
now add the second, as lam in possession of Irish specimens of the
hispida of both authors. — H.spmulosa, Montagu. HAucida*, Dra-
parnaud. H, nitidula, Draparnaud. H. alliaria, Miller. H. cry-
stallina, D rap. H.radiatula, Alder. H.pura?, Alder. H.pygmcea,
Drap. H. Scarburgensis , Bean. Clausilia bidens, Drap. Cary-
chium lineatum, Ferussac. Bulimus Acicula, Drap. Pupa edentula,
Drap. P. muscorum (a.), Drap. P. Secale, Drap. P.pygmcea, Drap.
P. Antivertigo, Drap. P. Vertigo, Drap. P. sexdentata, Alder.
P. (Turbo) Vertigo, Montagu. P. (Vertigo) Anglica, Ferussac. Pla-
norbis spirorbis, Drap. P.glaber? Jeffreys. P. lutescens, Lamarck,
or P. carinatus, Drap. As in the case of the Helix hortensis and

* This species should not perhaps be included here, as Mr. Jeffreys re-
marks of it, under the title of H. nitida, that he has received a specimen of
a variety of this shell from Mr. Dillvvyn as Irish.

Royal Astronomical Society, 301

Helix hispida, the synonyms of two distinct species are in the " Irish
Testacea " again appropriated to one. These are the Helta: planata
of Maton and Rackett and the H. carinata of Montagu, and as these
have not severally been given in any catalogue of the shells of Ire-
land, and my cabinet contains specimens of both species collected
there, one or other, the Planorbis lutescens of Lamarck, or P. cari-
natus of Draparnaud (to adopt modern names), remains now to be
added. — Valvata Planorbis, Drap.

A beautiful species ofLimneus, collected in the South of Ireland
by William Henry Harvey, Esq., of Limerick, and presumed to be
new to science, was also characterised by Mr. Thompson. It ap-
proximates the L. glutinosus more nearly than any other British
species of this genus.

A notice of an addendum to this paper subsequently read to the
Society will be found in our Number for July, p. 70.

ROYAL ASTRONOMICAL SOCIETY.

April 11. — The following communications were read : —

I. Places of the periodic Comet of 6*7 years, or Comet of Biela,
deduced from the Observations of Sir John Herschel at Slough,
and of Mr. Henderson at the Cape of Good Hope. By Mr. Hen-
derson.

The positions of the stars with which the comet was compared
were obtained partly from the catalogues of MM. Pond and Bessel,
but chiefly from observations made at the Cape Observatory.
Founded on these determinations, there are given — the comet's
apparent geocentric right ascension and declination on September
23rd and 24th, and November 3rd and 4th, 1832, deduced from Sir
John Herschel's observations — and on November 18th, 22nd, 23rd,
and 27th, December 26th and 31st, 1832, and January 1st, 2nd, and
3rd, 1833, deduced from the observations of Mr. Henderson.

II. Various Observations made at the Observatory, Cape of Good
Hope, in April and May 1833. Communicated by Mr. Henderson.

1. Observed Transits of the Moon and Moon-culminating Stars.
By Lieut. W. Meadows, R.N.

2. Observations of the Moon and Stars made with the Mural
Circle, on April 29th, 1833.

3. Observation of a Lunar Occultation of n Geminorum, made on
April 24th, 1833.

This additional series of observations made at the Cape Observa-
tory by Messrs. Henderson and Meadows, is a continuation of those
already communicated. (See Monthly Notice for June 1833.)

III. Results of a comparison of various Observations of Mars made
at Cambridge, Greenwich, and the Cape of Good Hope, for the de-
termination of the Sun's Parallax. By T. Henderson, Esq. In a
Letter to Professor Airy, dated Nov. 11th, 1833.

Mr. Henderson has compared various observations made at Cam-
bridge, and at Greenwich with both circles, with his own made at
the Cape of Good Hope ; and has deduced the correction of the
declination of Mars, as given in the Berlin Ephemeris. The results

302 Royal Astronomical Society.

are as follow : — Supposing the assumed solar parallax, 8"\578, to
be corrected as in the Cambridge Observations for 1832, pages 138
and 139, so that the true parallax is 8"*578 (I+aO, the value of jx is
determined as follows : —

Compared with Lhnb Valnoofw Parallax of © from

the Cape Obe. ljimb* Value of ^. mean of preceding.

Cambridge North -j- 0-01271 c„ -OQ

South -0-0102 f 8 '588

Greenwich \ /North -f 0*0895 \

9"*076
9"*343

(Troughton) J '""[South -j- 0*0265 J ""••

Greenwich 1 /North -f 0-0632)

(Jones) J '" I South -j- 0-1 152 j*

* The chief inference," Mr. Henderson remarks, " to be drawn
from the above observations appears to be, the probable accuracy
to be expected from similar observations at future periods."

Mr. Henderson states that the season in which these observations
were made was not favourable for delicate astronomical observations
at the Cape, as the south-east wind was generally prevalent, during
which the atmosphere is in a disturbed state. The season best
adapted for accurate observations there is from March to October,
or during the winter months.

IV. On a Clock for giving Motion in Right Ascension to Equa-
torial Instruments. By the Rev. R. Sheepshanks. This paper, il-
lustrated by an engraving, is given in the Monthly Notices of the
Society.

V. Stars observed with the Moon at Cambridge Observatory, in
the month of March 1834. Long. 23s*54« east of Greenwich.

May 9. — The following communications were read : —

I. Second Series of Micrometrical Measures of Double Stars
chiefly performed with the 7-feet equatorial. By Sir J. Herschel.

This second series is a continuation from vol. v. p. 90 of the Me-
moirs, and begins with No. 736, the last in the above-mentioned
page being 735. The observations have been almost entirely made
with the same achromatic of five inches aperture, except in the case
of a few difficult objects, for which the 20-feet reflector was used.
Many of them, and in particular all those of 1833, were made with
an increased magnifying power, which Sir J. Herschel calls 500, but
thinks may be something less. The action of the instrument under
this power is perfectly good ; and, having provided himself with
still higher powers, Sir. J. Herschel expects to be able in future to
avail himself fully of the excellent quality of the Object-glass, which
has hitherto become uniformly more apparent with every increase
of power which has been applied to it.

Sir John Herschel's observations end at No. 1, 111, and to them
are added a few made by Captain Smyth and the Rev. W. R. Dawes.

II. Micrometrical Measures of the Positions and Distances of
121 Double Stars, taken at Ormskirk, in the years 1830^-33. By
the Rev. W. R. Dawes.

These observations are given in the same manner as those of Sir
J. Herschel, and are 406 in number. For a description of the in-
strument employed, see Memoirs, vol. v. p. 1 35. Mr. Dawes further

Royal Astronomical Society. 303

states, that the mounting and entire arrangements of his 5-feet
achromatic are exactly similar to those of Capt. Smyth's larger in-
strument, described in the Memoirs, vol. iv. p. 550. The spherical
aberration is perfectly destroyed, and the discs of stars shown with
beautiful neatness on a dark ground.

ft Since the middle of the year 1831, I have uniformly placed the
stars between the parallel threads in measuring their position. This
plan, suggested to me by Sir J. Herschel, I much prefer to any other.

1 can also speak in the highest terms of the advantage accruing
from the use of a red illumination of the field; and I usually employ
as deep a colour as the light afforded by the lamp will permit. But
the most important improvement I have yet tried consists in the
interposition of a concave achromatic lens between the object-glass
and its principal focus, by which the focal image being enlarged to
above twice its original size, a very high magnifying power may be
obtained, while the threads of the micrometer appear of sufficient
fineness to permit the measurement in distance of very close and
minute stars without distortion. Having frequently felt the incon-
venience arising from the threads being magnified in proportion to
the power used on the telescope, I stated the difficulty to Mr. Dol-
lond, who speedily and most perfectly removed it by the application
of the lens above mentioned. The effect is the same, in respect of
the power of the telescope and the fineness of the threads, as if the
focal length of the object-glass were increased to about 10 feet

2 inches.

" The magnifiers, with the micrometer, have been varied accord-
ing to the object and the circumstances. At first I usually employed
226 j this was subsequently exchanged for 285, which was found
more generally efficient ; while 55, 80, and 1 40, were occasionally
applied for very faint objects, and 350, 480, 550, and 625, for very
close or bright ones. Since the acquisition of the concave achro-
matic lens, a power of 295 has been most frequently employed, by
using the eye-tube which without it magnifies 140 times; but in
very unfavourable circumstances, or on excessively faint objects,
170 has been occasionally substituted. The highest magnifier has,
however, generally been used, which the state of the atmosphere
and the brightness of the object would permit ; and great advan-
tage has frequently been derived from the use of 475 or even 600.

M With the five lower eye-tubes a diagonal prism can be employed,
the highest power to which it was originally applicable being 285 ;
but since with the second object-lens this eye-tube magnifies 600
times, the use of the prism is proportionally extended. And it
appears to me that much greater benefit may be derived from this
little appendage than merely the increased comfort to the observer,
in releasing him frequently from a very awkward position, and
placing him in one comparatively luxurious, though this alone exerts
no small influence on the correctness of these extremely delicate
observations. But I should chiefly recommend the prism to those
who are seriously engaged in these researches, as enabling the ob-
server to place the stars in any positions he may please with relation

304- Royal Astronomical Society.

to a vertical circle. Thus he may get rid of one of the principal
difficulties in measuring objects correctly, whose position is between
30° and 60° from the parallel, and which, I am persuaded, has had
a large share in producing the discordant results in the angles of
e Bobtis, 70 Ophiuchi, £ Bobtis, Canis Minoris 31, and others. By
simply turning round the eye- tube and its annexed prism, we may
place such oblique stars either vertically or horizontally, or we may
invert their relative situation ; and thus, by taking a few observations
in each apparent position, much may, I feel convinced, be done to-
wards destroying any bias of judgement which might arise from the
oblique position of the stars, or from an unconscious disposition to
place the threads of the micrometer in the direction of a tangent to
the discs of moderately unequal stars, and that principally on one side
of them."

Measures of distance were usually taken alternately on each side
of the zero, instead of employing an index correction. They are
in most instances decidedly smaller than those of MM. Herschel
and South, Phil. Trans. 1 824, and somewhat larger than those of
Professor Struve. Distances often vary to an astonishing extent
when the stars are well defined : at other times the converse takes
place.

A central disc on the object-glass was found to increase the
separating power of the telescope ; but the concentric rings round
bright stars were thereby multiplied, made more luminous, and
thrown further from the disc.

The estimated weight of each observation was fixed upon before
the index was read off; and every suspected observation was re-
made. If the second observation decidedly agreed with other
measures, the suspected one was rejected ; but if not, both were
made to form part of the set. All the original observations of the
series, 4400 in number, have been preserved.

Mr. Dawes makes several comparisons of his own observations
with those of others. With regard to some stars, he has found
reason to suspect some alteration j with regard to others, he can
give no support to surmises respecting their binary character.
Among the stars which furnished the former results, Mr. Dawes
mentions Ceti 292, y Ceti, 2 389, Tauri 34, 2 Camelopardalis,
38 Geminorum, H. I. 69, e Hydrce, 35 Sextantis, 44 Bobtis, £ Libra,
S. 757, H. 87, Pegasi 29, £ Aquarii, 2 3061 ; among the latter,
32 Eridani, H. L70, H. I. 84, H. III. 48, Canis Minoris 31, {Bootis,
B Serpentis, 2 2339, Tauri Poniat. 75, Cygni 280.

III. List of Observations made with the Transit Instrument, from
April 10 to May 24, 1833, and with the Mural Circle, from May 16,
1832, to May 24, 1833, at the Cape of Good Hope. From Mr.
Henderson.

The transit observations were made (with a few exceptions) by
Lieut. Meadows, and the circle observations by Mr. Henderson.

IV. Apparent Geocentric Positions of Encke's Comet, deduced
from observations made by Mr. Henderson and Lieutenant Mea-
dows, at the Observatory, Cape of Good Hope, and by M. Mossoti,

Royal Astronomical Society. 305

at Buenos Ayres, in June 1832. In a letter from Mr. Henderson
to Professor Airy.

These positions have been computed by Mr. Henderson from the
observations, and he has compared them with those interpolated
from Mr. Encke's accurate Ephemeris, communicated to the Society
in May 1832. Mr. Henderson considers, as a definitive result ob-
tained from the Cape observations, that the mean correction of the
ephemeris in right ascension is -f-2' 25" reduced to a great circle,
and in declination + 1'30", the mean corresponding date being
June 5, 1832.

V. Catalogue of the North Polar Distances of 60 Stars, reduced
to January 1, 1830, derived from Observations made at Greenwich
by the two circles and six microscopes, 1S25-1833. From the
Astronomer Royal. An Abstract of this paper is given in the
Monthly Notices.

VI. Stars observed with the Moon at the Royal Observatory,
Greenwich, from February 1833 to March 1834.

June 13. — The following communications were read:

I. Some remarks on the Greenwich mural circles, by the Astro-
nomer Royal.

The memoir lately published by Professor Airy, in which he
notices some discordances in the zenith points of the Cambridge
circle as determined by different stars observed directly and by re-
flection, induced Mr. Pond to examine whether one or both the
mural circles of Greenwich exhibited the same defects. The ob-
servations of 1825 and 1826 being very numerous and carefully
made, Mr. Pond has selected a series of differences of declinations
between certain stars observed in those years. As the altitude of
each star is obtained with each circle by direct and reflected vision,
independently, (the stars being in fact observed as church steeples
are with a theodolite,) it is evident that there are four combinations
of differences between every pair of stars, wholly free from any
hypothesis as to the absolute declinations, the agreement or dis-
agreement of which will show the accuracy or defects of the in-
struments. From the near coincidence of each result with the
mean, Mr. Pond concludes that the circles were at that time in a
satisfactory state.

II. Observations of the Solar Eclipse, July 16, 1833, at the
Cambridge Observatory. By Professor Airy.

Professor Airy considers the beginning or end of a solar eclipse
so unsatisfactory an observation compared with the mode adopted
by him on the present occasion, that he did not think it worth
while to note them at all. The instrument employed was a 5-feet
equatorial by T. Jones, magnifying power 100, which has been
noticed in the determination of the elongations of Jupiter's fourth
satellite and of the parallax of Mars. The only sensible error in
its adjustment was that in azimuth, which was unimportant in the
present instance, as the middle of the eclipse was almost exactly at
6h from the meridian. The observations were of differences of
N.P.D. and differences of R.A. When differences of N.P.D., as

Third Series. Vol. 5. No. 28. Oct. 1834. 2 R

306 Royal Astronomical Society,

of two cusps, were observed, the instrument was clamped in R.A.,
and one of the micrometer wires (this instrument has two), the posi-
tion of which was previously read off, was brought upon the cusp
by the tangent screw of the declination circle, as the cusp passed
the centre wire ; and the time was noted. The second cusp was
bisected by the second micrometer wire when it passed the centre
wire, the time being also noted and the micrometer read off after
the observation was made. The subjects registered in this observa-
tion are the clock times of the passages of the cusps, and the read-
ings of the two micrometers when the wires were placed upon each.
The differences of R.A. were obtained by observing the transits of
each cusp over all five wires when the interval allowed, and in other
cases over the three middle wires. These observations were care-
fully made on the same part of the wires, the declination circle
being undamped and moved by hand.

"By observing differences of either N.P.D. or R.A. of the cusps
near the beginning and near the end of the eclipse, the effects of
errors in R.A. and N.P.D. would have been obtained, largely multi-
plied and combined in opposite ways; and by observing differences of
N.P.D. of the cusps near the middle of the eclipse, the effects of
errors of R.A. would have been obtained with large multipliers. The
only defect in these determinations would be, that, as far as errors
in the semidiameters of the sun and moon enter, they always enter
with the same signs. There seems to be no good method of finding
the effects of errors in the semidiameters combined with different
signs, except by measuring the difference of declination of the N.
or S. limbs when those of both bodies are visible. It would, per-
haps, therefore, have been best to divide the duration of the eclipse
into five nearly equal parts, and to observe difference of N.P.D. of
cusps during the first, third, and fifth parts, and difference of N.P.D.
of limbs during the second and fourth. I am here supposing the ob-
ject to be (as mine was) to correct all the elements ; if the object were
only to ascertain differences of longitude (supposing the elements
corrected), it would be best to observe differences of R.A. of the
cusps during the second and fourth parts, as the whole of the mea-
sures thus obtained would vary rapidly with the time. Different
considerations will be necessary in every different eclipse ; and in
none can measures be made to the utmost advantage without more
of previous examination than I was able in the present instance to
give."

The observations made are,

1. Excess of N.P.D. of 1st cusp over that of 2nd cusp. 6 observations.

2. Excess of N.P.D. of sun's lower limb over 1st cusp. 4 observations.

3. Excess of N.P.D. of sun's lower limb over moon's lower limb. 5 obs.

4. Excess of N.P. D. of 2nd cusp over that of 1 st cusp. 10 observations.

5. Excess of R.A. of 2nd cusp over that of 1st cusp. 10 observations.

After pointing out the mode in which the corrections for refrac-
tion, parallax, &c.,are obtained, Professor Airy proceeds to calculate
the small variations depending on the errors of the tables, and to
obtain equations of condition involving the corrections of the R.A.,

Royal Astronomical Society. 307

N.P.D., and semidiameters of the sun and moon. The solution of
these equations, on the supposition that the place of the sun in the
Berlin Ephemeris is correct, shows that the true R.A. of the moon
at the time of the eclipse is less than that of the Berlin Ephemeris
by 19"-30, and less than that of the Nautical Almanac by 18"-55,
while the true north declination is less than that of the Berlin
Ephemeris by l''*26, and less than that of the Nautical Almanac
by 1"*21. These are the corrections which ought to be applied to
the tabular values of the moon's place in deducing longitudes, &c,
from observations of this eclipse.

III. On the position of the ecliptic, as inferred from transit and
circle observations, made at Cambridge Observatory, in the year
1833. By Professor Airy.

Those observations only were employed in which both limbs
were observed ; giving 140 transit, and 134 circle, observations,
six microscopes being read for each limb in the latter. The clock
errors were deduced from a catalogue differing from Pond's of 11 12
stars by a mean excess of 0S*11, and from Bessel's in the Tab. Reg.
by a mean excess of 0s* 18.

In the circle observations, the first limb was observed by setting
the instrument approximately, reading the microscopes, and mea-
suring the distance of the limb from the fixed wire by a micrometer
wire. The other limb was observed in the usual way. The re-
fractions used were Bessel's, the parallaxes those of the Berliner
Jahrbuck, both applied separately to each limb. The latitude of
the place was derived from 917 observations, with six microscopes,
of 10 circumpolar stars. See Camb. Ofor., vol. vi. The method
adopted, that of Normal Places, is thus described :

"In England, in deducing values of the obliquity, or places of
the equinox, from a set of observations, the usual method has been
to calculate from each observation by a trigonometrical operation
the place of the equinox, &c., and to take the mean of all the

f)laces so found. The method of Normal Places consists in calcu-
ating trigonometrically no single observation whatever; but in com-
paring every observation with the place in the ephemeris, in taking
the difference or apparent error of the ephemeris, in taking the
mean of all those apparent errors over an extent of time in which
we have h priori reason to think that they ought not to vary much,
and then in considering that we have thus obtained, for the mean
of all those times of observations, an error of the ephemeris which
is very much more accurate than any one error. By applying this
error with changed sign to a place in the ephemeris for a time near
to the mean of the times of observation, we obtain a single corrected
place, which possesses all the accuracy derived from the mean of
numerous observations ; and this is a Normal Place. The only
requisites for the ephemeris to be used in these calculations are, —
that it be consistently and accurately calculated on some elements,
and that these elements be not extremely far from the truth (their
being very near to it is of no importance whatever). We may now,
if we please, use the Normal Places for trigonometrical calculation,

2 It 2

308 Royal Astronomical Society.

or we may use the mean errors as the errors for the mean times, and
make our whole calculation one of errors."

By grouping the observations for each month, in the manner
above described, Professor Airy deduces from the comparison of
the errors which are given, that his observations (his own catalogue
of stars included) give the sun north of the ecliptic assumed in the
tables, by

- 1"-061 cos 0 long. - 0"-427 sin 0 long. -J- 0"-487.

The correction required by the first term is equivalent to a re-
duction of 0s* 18 in the right ascensions of the stars employed, being
the excess above Bessel's right ascensions which Professor Airy's
catalogue assumes ; showing that Bessel's place of the equinox is
precisely that deducible from the Cambridge Observations. " This
accuracy of coincidence," Professor Airy remarks, " is to a certain
degree accidental ; but I do not think that accident would extend
so far as to the difference between Mr. Pond and Bessel."

The second term implies that the obliquity is less than that of
the Berliner Jahrbuch by 0"*427.

The third term would imply that the sun moves in a small circle
of latitude 0"*487, which increases the apparent obliquity in summer
and diminishes it in winter. This result, similar to that obtained
from other circles, is made the occasion of introducing the following
remarks.

It is found that the difference of N.P.D. of a northern and
southern star observed directly is always less than the same by
reflected observation. At Cambridge a mean zenith point has been
obtained from northern, zenithal, and southern stars, and subse-
quent single observations are corrected by comparing the zenith
points deduced with the mean zenith point. All stars are thus
corrected, and, by graphical interpolation, the sun and planets
also ; and the result is confirmatory of the method, since without it
the discordance of obliquities would have amounted to five seconds.
On the actual discrepancy in question, Professor Airy observes,
1st, that an error of less than 0"*25 in the correction of the circum-
polar stars and the sun would entirely remove it; 2nd, that we are
not justified in positively asserting the mean of direct and reflected
observations to be the true difference of N.P.D. of two stars. He
is disposed to attribute it to a small defect in the tables of refrac-
tion, where a trifling error in the law, the constant, or the thermo-
meter readings, would remove it entirely. In this case the summer
observations would be the more correct. But these would only
require an increase of 07,06 in the Berlin obliquity — a quantity
much too small to be answered for.

IV. On the transit instrument of the Royal Observatory of
St. Fernando, and the manner of using it. By Don Jose Sanchez
Cerquero. An abstract of this paper is given in the Monthly No-
tices.

V. On the Mural Circle of the Observatory at the Cape of Good
Hope. By Mr. Henderson.

Royal Astronomical Society, 309

Mr. Henderson has here detailed the experiments and investi-
gations which he made for the purpose of ascertaining the cause of
the anomalies which had been observed in the Cape mural circle,
and of detecting the laws by which they are regulated. A similar
inquiry by Mr. Sheepshanks and Professor Airy has been already
published in Vol. V. of the Society's Memoirs.

The experiments on which Mr. Henderson grounds his investi-
gations are a series of readings at each fifth degree of the limb of
the instrument made with each of the six microscopes. The dis-
crepancies among the readings indicate that the figure of the limb
is that of an oval of small excentricity, and that the centre of
motion frequently changes its position.

A change in the position of the centre of motion occasions va-
riations in the readings of the single microscopes, which, however,
disappear in taking the means of two or any other number of equi-
distant microscopes.

The oval figure of the instrument requires that corrections should
be applied to the readings of the microscopes, in order to obtain
the true values of angles which the instrument describes. Angles
of 60°, however, as given by six equidistant microscopes, require no
correction, they being independent of the effect of errors of division,
and of the non-circularity of the instrument. The same holds true
with regard to angles of 120° measured with three microscopes, and
angles of 180° measured with two.

Assuming that the necessary corrections may be expressed by a
series of the form

a sin (U + &)-Vb sin (2 U + B) ■*■ c sin (3 U -f C) + &c.

a, b, c, &c, denoting constant coefficients, A, B, C, &c, constant
angles, and U any division of the limb, the observed differences
betwixt angles of 60° given by six microscopes, and by three and
two, afford data for the determination of «, b, c, &c, and A, B, C,
&c. Employing the method of minimum squares, Mr. Henderson
finds the correction of the mean reading of two equidistant micro-
scopes to be

5"-523 sin (2 U + 83° 4') + 0"«569 sin (4U-f 16° 46').

The correction of the mean reading of three equidistant micro-
scopes is

= l'H71 sin (3 U + 321° 8').
To determine the correction of the mean of six microscopes, an
additional pair was required ; but these not being at the Cape Ob-
servatory, Mr. Henderson has, from a consideration of the errors
of angles measured with two and three microscopes, and corrected
by the above formulas, inferred that the probable error of the un-
corrected mean of six microscopes is 0"*22. He also found reason
to suppose, that of the 720 different sets of divisions to which
observations read by the six microscopes are referred, there are,
according to the laws of probability, 328 whose errors are under
two tenths of a second, and one only whose error exceeds one
second. This degree of accuracy, Mr. Henderson remarks, ap-

310 Royal Astronomical Society.

pears to equal that of the best instruments of similar construction
hitherto made, and the astronomical observations confirm this esti-
mate.

Mr. Henderson next investigates the extent of the changes in
the position of the centre of motion, and the formula for repre-
senting them. It appears, that from an unsteadiness in the support
of one of the pivots of the axis, the centre frequently changes its
position by irregular quantities ; and that, owing to the non-circular
figures of the pivots, other changes in the position of the centre of
motion take place while the circle revolves on its axis. Formulae
for expressing the variations occasioned by the latter cause are
given, which are constant for the same positions of the circle. But
neither of these causes operates in the least degree to affect the
mean of the readings of equidistant microscopes ; and, on the
whole, Mr. Henderson is of opinion, that the accuracy of the
astronomical observations made with the instrument are not im-
paired to any sensible extent by any of the anomalies which have
been mentioned.

VI. Supplement to a paper on the Latitude and Longitude of
the Cape of Good Hope. By Mr. Henderson. See Monthly
Notices, vol. ii. p. 183, or Memoirs, vol. vi. p. 125.

The preceding determination, from Mr. Fallows's observations
in 1829 and 1830, gave the longitude of the Cape Observatory
lh 13m 55s*8 East. Mr. Henderson deduces lh 13m 54s*4 from his
own observations in 1832 and 1833. The mean is lh 13m 55s' 1,
which, rejecting the 0s* 1, Mr. Henderson proposes to adopt, until
the uncertainty is removed. The difference of longitude of Green-
wich and the Cape is determined from 17 observations of the moon's
first limb, and 6 observations of the second ; that of Cambridge and
the Cape from 16 and 8 observations of the first and second limb.

VII. Observations of the Comet of 1830, made at Ascension
Island, by the late Captain Henry Foster, R.N., F.R.S., and re-
duced by Mr. Henderson.

VIII. Addition to a letter to Professor Airy, dated Nov. 11, 1833,
on the Sun's Parallax. By Mr. Henderson. See Monthly Notice
for April 1834, vol. iii. page 39.

Mr. Henderson has compared the Altona observations, Ast.Nach.,
No. 240, with his own at the Cape. He finds for the values of /x
(see preceding reference) from the planet's north and south limb,
•0721 and -0507; from the mean of which he deduces 9"*105 for
the mean horizontal parallax. The mean of all the determinations
is 9"*028, the result being too great, as was also that of a similar
method of observation in the time of Lacaille.

IX. A letter from Professor Santini to the Secretary, dated
Sept. 17, 1833, containing results of computations of the perturba-
tions of Biela's Comet.

The letter gives the results of a memoir inserted in the Annali
delle Scienze, &c. Padua. The re-examination of the computations
was undertaken to detect the difference between the results of
MM. Santini and Damoiseau, as to the time of the perihelion
passage. An error discovered by M. Santini in the constants of the

Zoological Society. 811

variation of the daily motion brought the two results much nearer ;
but a difference still remains between the observed times of perihe-
lion passage in 1826 and 1832, such as would arise from a resisting
medium. Towards ascertaining this point, M. Santini has recom-
puted the perturbations caused by Jupiter with the values of the
mass given by Laplace and by Professor Airy. Some of the results
are given in the Monthly Notices,

X. Stars observed with the Moon at the Royal Observatory of
Cadiz, from May to December 1833. Communicated by Don
Sanchez Cerquero.

XI. Occultations of £ Tauri, Oct. 4-, 1833, — of e Tauri, March
16, 1834-, — and of v Virgmis, April 20, 18341, observed at Saville
Row. By R. Snow, Esq.

XII. Eclipse of the Sun, July 17, 1833, observed at the New
Observatory of Geneva. By M. Wartmann.

The corrected times of the beginning, middle, and end of the
eclipse were as follow :

Geneva Sid. Time.

Beginning 1* 3m 52"

Middle 1 53 28

End 2 43 24

Instrument, an equatorial of Ramsden, of 25 lines' aperture; power
30. Bar. 732 millimetres; therm. + 12°*8 Reaumur; both nearly
steady the whole time. The diminution of light by Nicod's photo-
meter was almost insensible, though perfectly appreciable by the
naked eye, and though two thirds of the sun's disc was eclipsed.
With a power of 135, the lunar mountains were distinctly visible.
M. Wartmann remarks, " La cir conference de notre satellite pa-
rassait comme dentelee, cest-a-dire Jbrmee d"asperites et de depres-
sions!'

XIII. Transits of the Moon with Moon-culminating Stars, ob-
served at Cambridge Observatory in the months of April, May, and
June, 1834?.

ZOOLOGICAL SOCIETY.

June 1 0. A collection of objects of Zoology, made by Lieut. Allen,
R.N., Corr. Memb. Z. S., during his late expedition up the Quorra into
the interior of Africa, and presented by him to the Society, was exhi-
bited. It was accompanied by another collection formed by the same
gentleman at Fernando Po. They comprehended a previously un-
described species of Plover; an undescribed Tetrodon and a Myletes;
specimens of Polypterus Senegalus, Cuv., and of a Gymnarchus, Ej. j
and specimens of the three- horned Chamceleon, Chamceleo Oweniy
Gray, and of a Galago, Galago Senegalensis, Geoff, j the two latter
being from Fernando Po. They also included numerous Injects and
Arachnida, both from the interior and from the island.

The bird was characterized by Mr. Gould as Vanellvs albiceps.
Between the eye and the upper mandible is situated a fleshy sub-
stance (resembling that of the common Cock) which hangs down at
right angles with the beak j it is of an orange colour, and is narrow

S12 Zoological Society.

in form, being one inch and a half long and half an inch wide at the
base, whence it gradually tapers throughout its whole length to the
tip. The spur on the shoulders is strong and sharp, and is nearly an
inch in length.

The Fishes were characterized by Mr. Bennett, who remarked on
the complete analogy borne by these species of the rivers of Western
Africa to some of those of the Nile. The form of Myletes, Cuv., to
which Lieut. Allen's fish belongs, has hitherto been obtained only in
Egypt j the genus Polypterus, Geoff., originally observed in the
Nile, seems to be limited to that river and to Senegal ; the genus
Gymnarchus, Cuv., has previously been noticed only in the Nile; and
the Tetrodon of this collection resembles in its markings that of
Egypt. The new species were characterized as Myletes Allenii and
Tetrodon strigosus.

The exhibition was resumed of the new species of Shells collected
by Mr. Cuming on the western coast of South America and among
the islands of the South Pacific Ocean. Those brought on the pre-
sent evening under the notice of the Society were accompanied by
characters by Mr. G. B. Sowerby. They belonged to the genus
Petricola, and were named as follows :

Petric elliptica, oblonga, solida, discors, concinna, denticulata,
rugosa, tenuis, robusta, and amygdalina.

The following " Description of a new Genus of Gasteropoda, by
W.J. Broderip, Esq., Vice President of the Geological and Zoological
Societies, F.R.S., &c." was read.

SCUTELLA.

Testa Ancyliformis, intus nitens. Apex posticus, medius, invo-
lutus. Impressiones musculares duse, oblongo-ovatse, laterales.
Apertura magna, ovata.

Animal marinum.

This genus appears to be intermediate between Ancylus and Patella,
while the aspect of the back sometimes reminds the observer of Navi-
cella or Crepidula, Lam. Its place will most probably be among
the Cyclobranches of Cuvier.

The two muscular impressions are situated on each side of the in-
terior a little below the summit j while, in Patella, they nearly
surround the internal circumference of the same part of the shell.
The aperture is generally surrounded by a margin, and the apex,
which in Ancylus is oblique, is central though posterior.

Mr. Cuming brought home the following species which I now pro-
ceed to describe.

Scutella crenulata. Scut, testa subeonicd, cancellatd, striis ab
apice radiantibus exasperatis, albd ; int-us nitente ; annulo mar-
ginali et margine crenulatis : long, -g- , lat. £, alt. TV poll.

Hab. ad insulam Aniian (Chain Island).

This shell was found dead on coral sand on the beach of the island
at a distance from any fresh water.

The marginal ring is very strongly developed, and the margin it-
self is not even j for when the shell is placed with the aperture down-
wards on a flat surface, it rests on the two ends, the sides of the
margin forming each a low arch.

Zoological Society. S 1 3

Scutella iridescens. Scut, testd oblongo- ovatd ', complanatd, mi-
nutissime substriatd, albo et roseo guttatim tessellatd; intits iri-
descente, margine interno albo, roseo maculato : long, -r3^, lat. iV>
alt. t«t poll.
Hab. in Oceano Pacifico. (Grimwood's Island.)
This species was gathered by Mr. Cuming on the sands when the
tide was out. There was no fresh water near, and though he obtained
several individuals in the finest condition, the soft parts were gone,
having evidently but lately fallen a prey to some carnivorous crea-
ture.

The shape of Seut. iridescens is very elegant, and the silvery iri-
descent nacre which lines the inside of the shell, contrasted as it is
with the less brilliant but lively coloured margin, is almost dazzling.
The back of the shell, which is very brittle, is mottled with white and
rose colour. This disposition of its markings almost conveys the im-
pression that the surface of the back is uneven ; but with the excep-
tion of the very minute stria, which are almost imperceptible, it is
smooth.

Scutella rosea. Scut, testd subconicd, striatd, albd, lineisjlani-
mulisque roseis ornatd; intus nitente, interdum subiridescente :
long. -£-, lot. nV, alt. tV poll.
Obs. Varietas forsan praecedentis.
Hab. cum prsecedente.

The shape and many other points in this shell differ from those of
Scut, iridescens. Externally it is much more conical and the strice.
which run from the apex to the interior margin are direct and minute,
while those which are lateral are much coarser and cross the some-
what elevated white parts obliquely : in Scut, iridescens, the exceed-
ingly minute strice radiate evenly from the apex. In Scut, rosea we
lose the brilliancy of the internal nacre which distinguishes Scut,
iridescensy and, in some individuals, it is entirely absent. Stlil the
former may only be a variety of the latter: both were found to-
gether.—W. J. B.

The Shells described in this communication were exhibited.
A note by Mr. G. Bennett, Corr. Memb. Z.S., was read. It gave
an account of a Pelican now living in the grounds of Mr. Rawson at
Dulwich, which wounded itself just above the breast to such an ex-
tent as to expose a spacious cavity. The bandages applied to the
part were repeatedly torn off by the bird for the space of ten days, at
the expiration of which the wound was healed. During the whole of
the time the bird was in perfect health; eating fish and drinking as
usual. The scar of the wound is still readily observable.

June 24. — A letter was read, addressed to the Secretary by Keith
E.Abbott, Esq., and dated Trebizond, Dec. 10, 1833. It referred
principally to a collection of objects of Zoology formed by the writer
in his neighbourhood and presented by him to the Society; and con-
tained notices of other objects which he expects to be able to procure
and transmit.

It also gave some account of" the famous honey of Trebizond, which
is spoken of by Xenophon in his history of the retreat of the ten thou-
Third Series. Vol. 5. No. 28. Oct. 1834. 2 S

1 !• Intelligence and Miscellaneous A rticles.

'S

sand Greeks, as having produced the effect of temporary madness or
rather drunkenness on the whole of the army who ate of it, without,
however, causing any serious consequences. It is supposed to be
from the flowers of the Azalea Pontica that the Bees extract this
honey, that plant growing in abundance in this part of the country,
and its blossom emitting the most exquisite odour. The effect which
it has on those who eat it is, as I have myself witnessed, precisely
that which Xenophon describes : when taken in a small quantity it
causes violent head -ache and vomiting, and the unhappy individual
who has swallowed it resembles as much as possible a tipsy man j a
larger dose will completely deprive him of all sense and power of
moving for some hours afterwards." A portion of the honey accom-
panied the letter, and was exhibited.

The other objects presented by Mr. Keith Abbott were also exhibited.

At the request of the Chairman, Mr. Gould brought the Birds se-
verally under the notice of the Meeting. Their principal interest
rested on the assistance afforded by a collection formed in such a loca-
lity towards the determination of the geographical limits of certain
species. Those among the Birds of Europe which are found in India
also would, it is reasonable to anticipate, occur in the intermediate
locality of Trebizond ; but there are, among the Trebizond Birds,
various European species which do not, as far as is yet known, occur
in India, and the existence of which in so eastern a range is conse-
quently interesting. A list of them, with remarks by Mr. Gould as
to their localities, is given in the Proceedings of the Society.

XLIII. Intelligence and Miscellaneous Articles.

PREPARATION OF OSMIUM AND IRIDIUM. BY M. PERSOZ.

THE method of separating these metals depends, 1st, upon the ac-
tion of crude platina upon mixtures of carbonate of potash or soda
with sulphur, which produce sulphurets of iron, osmium and iridium,
and a silicate of these bases, and which collect in the form of scoriae
on the surface of the mass in fusion j 2ndly, upon the action of
oxygen at a high temperature on the sulphuret of osmium, and from
which results a blue volatile compound, described by Berzelius.

The process of sulphuration for acting upon metals has already
been employed with so much success by MM. Berthier and Wohler,
that I had every reason to hope it might be applied to the extraction
of osmium and iridium, the alloy of which is one of the most refrac-
tory known.

A perfect mixture is to be made of one part of the ore of platina,
after the action of aqua regia, two parts of carbonate of soda, and three
parts of sulphur: this mixture is to be gradually projected into an
earthen crucible previously made red hot, and when the whole has
been put in, the crucible is to be covered, and kept white hot for a few
minutes. When cold the bottom of the crucible will be found to
contain a button formed of small crystals having the appearance of
pyrites j these are the sulphurets of all the metals which the ore con-

Intelligence and Miscellaneous Articles. 315

tained, and some of them are combined with sulphuret of sodium.
This button is covered with a layer of pure sulphuret of sodium, the
middle of which contains a small quantity of the crystals of sulphuret
of osmium j lastly, the surface of the fused mass is the crust of sili-
cate of a light brown colour.

The scoriae being separated from the fused mass of sulphurets, it is
to be put into water j this dissolves the alkaline sulphuret, the double
sulphuret of platina, if any should exist in it, and the sulphuret of
sodium combined with the sulphuret of osmium and iridium ; there
remain suspended in the liquid, the sulphurets of iron, osmium, and
iridium, which are to be suffered to subside ; by repeatedly washing
and subsiding all the metallic sulphurets, are separated from the
fragments of crucibles and scoriae.

The separated sulphurets are to be treated with hot dilute muriatic
acid, which dissolves the iion with the evolution of sulphuretted hy-
drogen gas. As soon as the action is over, the whole is to be thrown
on a filter, which retains the sulphurets of osmium and iridium : these
when thoroughly washed have the appearance of plumbago. In order
to separate the osmium from the iridium, a mixture is made of one
part of these sulphurets and three parts of sulphate of mercury : this
is to be put into an earthen retort, with a tube adapted for the disen-
gagement of gas. The retort is to be placed in a common furnace,
and gradually to be made intensely hot. As soon as the retort be-
comes nearly red hot, a great quantity of sulphurous acid is evolved,
and the heat increasing, vapours arise, which condense on the sides of
the adopter into a dense indigo coloured liquid. When the evolution
of gas has ceased, the apparatus is allowed to cool, and oxide of iri-
dium is found in the retort. To reduce it to the metallic state it is to
be heated in a porcelain tube and hydrogen gas passed over it : when
cooled in this gas, the metal is obtained, resembling spongy platina
in appearance. It readily inflames hydrogen gas.

Sometimes the iridium is not quite free from osmium ; in this case
it is to be fused with potash in a silver crucible : osmiate of potash is
formed, which dissolves in water, and a little iridium is also taken up.
The whole is to be filtered : the oxide of iridium remaining on the paper
is to be well washed, and then dissolved in muriatic acid. To this so-
lution, when concentrated, muriate of ammonia is to be added, this
occasions the precipitation of a double black chloride, which after wash-
ing and calcining yields pure iridium. Much osmium is found in the
neck and adopter of the retort, but in the former it is in the state of
oxide combined with mercury, while the latter contains the blue sub-
stance already mentioned, and consisting of osmium, oxygen, and
sulphur.

To separate the osmium from the mercury, it is sufficient to intro-
duce it into a glass tube, slightly inclined, through which a current of
hydrogen is passed, while the tube is slightly heated, the mercury is
volatilized, and the pure osmium remains.

The osmium of the blue compound may be separated by zinc, 01
still better by treating it merely with water, which converts it into
another compound of a brown colour and insoluble in water. When

2S2

316 Intelligence and Miscellaneous Articles.

washed and dried it may be reduced by hydrogen in the manner above
mentioned : in this operation water and sulphuretted hydrogen are
produced. — Ann. de Chim. et de Pkys., torn. lv. p. 2 10.

PURIFICATION OF CARBONATE OF SODA. BY M. GAY LUSSAC.

This salt is commonly purified by repeated crystallization, but it
retains so large aquantity of interposed mother liquor that ir.any ope-
rations are required to entirely free it from other substances, and
after all but a small quantity is obtained. The following process
having appeared to me extremely advantageous, I think it may be
useful to make it known.

This process is analogous to that which is followed in France for
purifying nitre. It is as follows : — Take the crystals of carbonate of
soda, such as are met with in shops; having washed them, make a sa-
turated hot solution ; when this is set to cool, stir constantly with a
rod or spatula to disturb the crystallization and to obtain small crystals
resembling sand : the cooling may be accelerated by placing the ves-
sel containing the saline solution in cold water. It sometimes hap-
pens that when very much cooled the solution does not crystallize,
and that it suddenly becomes solidified. This is the moment to stirvery
rapidly, to prevent the conglomeration of the crystals. This delay in
the crystallization may be prevented by throwing a few crystals into
the solution at the moment when it begins to be supersaturated.

Having obtained the crystals, put them into a funnel, in the neck
of which place a little tow or cotton to retain them. At first let them
drain, then wash them with small quantities of distilled water, waiting
till the preceding washing has run through. Test from time to time
the washings with nitrate of silver, the washing being previously satu-
rated with pure nitric acid : the purification of the salt is complete
when the liquid remains transparent. By this process, and in the first
operation, the greater part of the carbonate of soda employed may be^
obtained in a perfectly pure state. The mother liquor and the wash-
ing may be evaporated and treated in the same manner. The same
mode of purifying may be used with advantage for many other salts.
Its 'efficacy is founded upon the extreme facility with which water
runs through and well washes sandy crystals, such as are obtained
by disturbing the crystallization. —^wn. de Chim. et de Phys., tom.lv.
p. 22 1 .

FOSSIL WAX OF MOLDAVIA. BY M. MAGNUS.

This substance is evidently a mixture of several different matlers.
It is indeed true that this is not immediately seen, for though it has
sometimes the fibrous structure of amianthus, and is sometimes con-
choidal in its fracture, it yet appears to be homogeneous; if, however,
one of the small leaves of which it is composed be carefully examined,
small deep coloured points are visible. When the fossil wax is boiled
with even absolute aether or alcohol, but a very small quantity is dis-
solved, whilst the greater part of the remaining portion has an eaten
appearance, which shows that the mass is composed of two substances,

Intelligence and Miscellaneous Articles* 317

one of which is soluble and the other insoluble in alcohol. They are,
however, so intimately mixed, that it is impossible to separate them
by mechanical means. Oil of turpentine, at a high temperature, dis-
solves fossil wax completely.

It melts at 177° Fahr. without suffering any change. Its fusing
point is therefore higher than that of bee's wax, which js 144° Fahr. -7
the fossil wax does not lose it3 greenish brown colour nor its peculiar
empyreumatic odour by melting.

In order to explain the formation of this wax, it appeared to me
interesting to know if it contained any azote. 1 burnt it with oxide
of copper according to Liebig's method. 0"200 gr. yielded 02755 of
water and 06205 of carbonic acid, which show that it is composed of

Carbon 8575

Hydrogen 15*15

10100
The excess was owing to the volatilization of a portion of the wax
without decomposition, which took place in spite of every precaution.
It contains therefore neither oxygen nor azote, and its composition
approaches that of olefiant gas. — Ibid. p. 218.

CAUTION TO EXPERIMENTERS WITH THE ELECTRICAL KITE.
BY MR. STURGEON.

On Friday last, about half-past two in the afternoon, clouds began
to form in various quarters of the heavens in rapid succession, from
mere specks or streaks to immense groups, with every appearance
of being highly electrical.

I repaired to the Artillery Barrack grounds with an electric kite,
and in a very short time got it afloat, letting out string through the
hands from a coil or clue which was thrown on the ground. When
about a hundred yards of the string had been let out, a tremendous
discharge took place, which gave me such a blow in the chest and
legs that I became completely stunned, let go the string, and con-
sequently the kite soon fell.

The accident was owing entirely to my own neglect, and could
not possibly have happened had I taken the following precaution.

Let all the string intended to be employed be first taken off the
reel or coil, and stretched on the ground. Let now the insulating
cord, riband, glass, or whatever is used for this purpose, be attached
to the kite-string and fastened to a peg, tree, or anything intended
to hold the kite during the time it is up. Next fasten the kite to
the other end of the string, and let it ascend from the hand.

This is the manner in which I usually proceed when heavy clouds
are hovering about, and ought always to be attended to, although I
neglected it on this occasion. The experimenter by this means is
completely out of danger; and he may easily ascertain if the string
be highly charged by going to the other end, because of the brushes
of light, and noise attending them.

I find it convenient to have a sliding copper wire on the silken
cord, which can be moved, by means of a long glass rod, to any re-

318 Intelligence and Miscellaneous Articles.

quired distance from the wired string, the other end being stuck
fast in the ground. If the electric fire strikes two inches over the
dry silken cord, (and it will sometimes strike a yard,) it would not
be safe to approach it; and no man could hold the string when it
strikes over one inch of the silk, or, which is the same thing, through
the air.

After the electrical state of the string has been ascertained, the wire
may be slided away from it as far as possible (the silk ought never
to be less than two yards long). The other end is then to be taken
out of the ground and attached to the apparatus for experiment.
The wire is again slided up to the wired string, and left there during
the time the experiments are carrying on.

The only method of getting the kite down during an intense
electrization of the string, with safety to the experimenter, is to
unfasten the silken cord from its hold and let all go: the kite falls.
I have frequently been annoyed, whilst holding the kite-string during
hot hazy days when no cloud was visible, by a rapid succession of
discharges, from which I had no other means of escape than by
quitting the string and letting the kite fall. The same thing some-
times happens in cold dense fogs in the winter. 1 have experienced
these rattling or tremulous shocks when the kite has not been more
than 30 yards from the ground, and the wired string at the same
time touching it. Hence great quantities of the fluid must neces-
sarily pass into the ground directly through the wire, in addition to
that which produced the shocks.

The publication of these particulars may possibly prevent some
inexperienced electrician from receiving a death-blotf from his kite-
string.

Young persons who are fond of kite-flying should also be cautious
not to have their kites up during thunder storms, as it is possible
that a wet string may transmit a violent discharge, from which a
serious accident might occur.

Artillery Place, Woolwich, July 23, 1834. W. Sturgeon.

ON SOME REMARKABLE CRYSTALS OF SNOW. BY W. THOMPSON,
ESQ., V.P. BELFAST NAT. HIST. SOC.

On the 22nd of March 1833, when travelling outside a stage-
coach from London to Shrewsbury, and near to Daventry, the day
being up to this time mild and calm, (the weather for some weeks
previously had been excessively cold, with prevalent easterly and
north-easterly winds,) snow of the loose flaky kind, common to the
climate, began to fall, but mingled with it there appeared beautifully
delicate lamellar crystals, of uniform transparency, having a sphe-
rical nucleus, from which sprang 6 and 12 radii most exquisitely
formed, all the rays on each species being equal, and not in a single
instance deviating from the regularity oi* geometrical proportion, as
has on some occasions been observed. By far the greater number
of these were of the former species, " having 6 points radiating from
a centre." The figures 20 and 94« in the plates of snow crystals in
Scoresby's "Arctic Regions" represent both these crystals, the lines

Intelligence and Miscellaneous Articles. 319

exhibited as extending from the centre of the latter not having been
however visible to the naked eye. These stellate crystals> varying from
l£ to 2 lines in extreme diameter, continued to fall for nearly half
an hour, and as they retained their form for a considerable time,
proved highly interesting and attractive. I much regretted that I
was so circumstanced as to be unable to ascertain the state of the
barometer and thermometer; the wind, however, was northerly with
a point of east. Snow continued to fall until the coach reached
Shrewsbury ; and in passing through Wales the next day, which
was remarkably fine, I observed that it had fallen there in every
direction. Arriving in Ireland on the 24th, I remarked that the snow
had also extended to that country, the Wicklow and Dublin moun-
tains being covered with it.

In anticipation of it being thought singular that I have not before
recorded the fall of these ice- crystals, it may be stated that I delayed
in the hope that some one better circumstanced for precise inves-
tigation had noticed the occurrence, and would have written on the
subject of it. In expectation of this I have looked over the various
British periodicals since published, and nothing having appeared
concerning it, I presume it to be better that even the present im-
perfect account should be recorded than none at all.

Wm. Thompson.

obituary : — professor harding.

We have to record the death of Professor Harding of the Uni-
versity Gottingen, an eminent astronomer, whose name will go down
to posterity with the important discovery of the planet Juno, which
it was his good fortune to make in 1804. He was descended from
a highly respectable English Catholic family. One of his ancestors
left England on account of his religion, and settled in Germany,
where the family afterwards became Protestants. He was born at
Lauenburg, the principal town of the then Hanoverian, now Danish
duchy of Lauenburg, and was originally intended for the church ;
but after his academical studies, he became tutor to the son of the
celebrated astronomer Schroter, and this circumstance led him to
the study of practical astronomy, to which he afterwards exclusively
devoted his whole life. After having been several years astrono-
mical assistant to Schroter, he accepted in 1805 a Professorship of
Astronomy at Gottingen, which he retained till his death.

Professor Harding was a most active and industrious practical
astronomer, whose observations have, in no small degree, enlarged
our knowledge of the heavenly bodies. He rendered a very im-
portant service to astronomy by compiling accurate maps of those
parts of the heavens in which planets may be expected to appear.
The perseverance and careful attention with which he mastered the
heavens during several years in the prosecution of this work, were
rewarded by the brilliant discovery above alluded to. He was a
very amiable man, whose loss is much deplored by his numerous
friends and colleagues in the university. The grief at the loss of
his daughter, an only child, 14 years old, who died last year, ter-
minated his days on the 31st of August last, at the age of about
70 years.

►4

Remarks.

r

. — _ _

London. — A ugust 1 . Foggy : fine. 2. Cloudy :
fine. 3. Very fine. 4. Foggy : very fine. 5. Cloudy
and fine. 6. Heavy showers. 7. Showery : heavy
rain at night. 8. Rain. 9. Sultry. 10 — 22. Very
fine. 23. Fine : slight showers. 24. Fine : heavy
showers at night. 25. Showery. 26. Slight
showers : very fine. 27. Heavy dew : fine .
28. Fine but cool : rain at night. 29. Cloudy,
with slight showers. 30. Fine : very heavy rain
at night. 31. Cloudy and fine.

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1834.

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THE

LONDON and EDINBURGH

PHILOSOPHICAL MAGAZINE

AND

JOURNAL OF SCIENCE.

+.

[THIRD SERIES.]

NOVEMBER 1834.

XLIV. Experiments on Light*. By H. F. Talbot, Esq.,
M.P.,F.R.S.

§ 1 . Microscopic Appearances with Polarized Light.

\ MONG the very numerous attempts which have been
£*■ made of late years to improve the microscope, I am not
aware that it has yet been proposed to illuminate the objects
with polarized light.

But as such an idea is sufficiently simple and obvious, it is
possible that some experiments of this kind may have been
published, although I am not acquainted with them. I have
lately made this branch of optics a subject of inquiry, and
I have found it so rich in beautiful results as entirely to sur-
pass my expectations.

As little else is requisite to repeat the experiments which
I am about to mention than the possession of a good micro-
scope, I think that in describing them I shall render a service
to that numerous class of inquirers into nature, who are de-
sirous of witnessing some of the most brilliant of optical phe-
nomena without the embarrassment of having to manage any
large or complicated apparatus. And it cannot be without in-
terest for the physiologist and natural historian to present him
with a method of microscopic inquiry, which exhibits objects
in so peculiar a manner that nothing resembling it can be
produced by any arrangements of the ordinary kind.

In order to view objects by polarized light, I place upon

* A paper read to the Royal Society, July 1834.
Third Series. Vol. 5. No. 29. Nov. 1 834. 2 T

322 Mr. H. F. Talbot's Experiments on Light.

the stage of the microscope a plate of tourmaline, through
which the light of the large concave mirror is transmitted be-
fore it reaches the object lens. Another plate of tourmaline
is placed between the eyeglass and the eye ; and this plate is
capable of being turned round in its own plane, so that the
light always traverses both the tourmalines perpendicularly.
The mirror being adjusted so as to reflect the daylight into
the body of the microscope, and no object being as yet placed
on the stage, it follows, as indeed is obvious to all who are
conversant with this branch of optics, that if the two tourma-
lines are placed in a similar position, the light freely traverses
them both : but if that which is next the eye is turned round
90°, the observer can perceive nothing, except when the light
of the sun is used, which causes a small remnant of the light
to become visible. Except in this case, however, the field of
view is quite dark in this position of the tourmalines, and par-
tially bright in the opposite position. It is only partially,
and not entirely bright, because even the best tourmalines have
a considerable tinge of brown or green colour, which greatly
disturbs and disfigures the colours of all bodies which are
viewed through them.

In consequence of this defect I found it advisable to abandon
the use of tourmalines, and to adopt, instead, an arrangement
of single-image calcareous spar, the invention of which is due
to Mr. Nicol. As I have examined the theory of this instrument
in another place*, I shall not revert to it at present further
than to say that the effect it produces is entirely similar to that
of the tourmaline, but that it possesses over that mineral the
precious advantage of perfect whiteness and transparency.

This instrument has nearly the form of a four-sided prism
with a rhomboidal base, and it is conveniently placed in the
axis of a small brass tube, which is screwed on as close above
the eyeglass as possible, and forms a prolongation of the tube
of the microscope. A similar tube is screwed beneath the
stage of the microscope to transmit and at the same time po-
larize the light of the mirror.

This arrangement is found to answer extremely well, for
when the two polarizing instruments are placed in a similar
position, the field of view is bright and perfectly white; but
when the one next the eye is turned round 90°, the field of
view is completely dark. It is in the latter situation that the
microscope is generally to be used.

Having fitted up a microscope in the manner described, let
us take for the object of examination a hair. In order to make

# See Lond. and Edinb. Phil. Mag., vol. iv. p. 289.

Mr. H. F. Talbot's Experiments on Light. 323

it perfectly transparent, and to prevent the diffraction of light,
it should be immersed in oil or varnish and pressed between
two plates of glass. The field of view having been darkened
as much as possible in the manner before described, the hair
is placed upon the stage of the microscope, and it is then seen
to be beautifully luminous. As no other light reaches the
eye than that which traverses the hair, every minute circum-
stance in its interior structure is plainly distinguished. Jt is
almost needless to say that this effect is owing to the de-
polarizing power of the hair. Many organic substances of
animal and vegetable origin appear luminous in a similar way,
while others, on the contrary, are inert, and have no such ac-
tion upon light.

Fragments of coarsely powdered sugar and of various kinds
of salts appear more or less bright, and mottled with various
colours; but common salt is an exception, as it remains nearly
or altogether dark, at least when it is employed in a state of
purity.

But when instead of examining amorphous fragments of
these salts we view them regularly and carefully crystallized,
the phaenomena become much more interesting. Sulphate of
copper offers a very excellent example. This salt, which is of
a fine blue colour when viewed in considerable thicknesses,
is white and transparent when it is extremely thin, and its
crystals can be procured so small as to be quite destitute of
perceptible coloration. A drop of it was placed upon a warm
piece of glass and suffered to evaporate gradually. The cry-
stals shooting from the edge of the drop into the interior of
the liquid had a long and narrow rectangular form, with a
slanting extremity, which may be compared in shape to the
straight edge of a chisel. Seen by common light these cry-
stals offer nothing peculiar, but on the darkened field of the
microscope they are luminous and splendidly coloured, the
colour depending upon the thickness of the crystal, and being
the same in all points of its surface, except upon the little in-
clined plane which forms its extremity. But upon this oblique
portion are seen three or four distinct bands of colour parallel
to the edge and offering to the eye a visible scale or measure
of the rapid diminution of thickness in that part. The ob-
served succession of colours in one experiment was the fol-
lowing. Yellow, brown, purple, blue, sky blue, straw yellow,
yellow, reddish purple, blue, sea green, green, greenish yellow,
pink, green, pink, blueish green, pink.

Taking, again, for the subject of experiment the sulphate of
copper, we may make it crystallize in quite another manner,
by not employing any heat, but simply touching the drop

2T2

324 Mr. H. F. Talbot's Experiments on Light.

with an exceedingly small portion of nitric aether. This
causes in a short time a deposition of minute crystals in the
form of rhomboids, exquisitely perfect in shape and transpa-
rency, and of every variety of size.

When these miniature crystals are placed on the stage of
the microscope, the field of view remaining dark as before,
we see a most interesting phenomenon ; for as every crystal
differs from the rest in thickness, it displays in consequence a
different tint, and the field of view appears scattered with the
most brilliant assemblage of rubies, topazes, emeralds, and
other highly coloured gems, affording one of the most pleas-
ing sights that can be imagined. The darkness of the ground
upon which they display themselves greatly enhances the
effect. Each crystal is uniform in colour over all its surface,
but if the plate of glass upon which they lie is turned round
in its own plane, the colour of each crystal is seen to change
and gradually to assume the complementary tint. Many
other salts may be substituted for the sulphate of copper in
this experiment, and each of them offers some peculiarity,
worthy of attention, but difficult to describe. Some salts,
however, crystallize in such thin plates that they have not
sufficient depolarizing power to become visible upon the dark
ground of the microscope. For instance, the little crystals of
sulphate of potash, precipitated by aether, appear only faintly
visible. In these circumstances a contrivance may be em-
ployed to render evident their action upon light. It must be
obvious that if a thin uniform plate of mica is viewed with the
microscope, it will appear coloured (the tint depending on the
thickness it may happen to have), and its appearance will be
everywhere alike, in other words it will produce a coloured
Jield of view. Now if such a plate of mica is laid beneath the
crystals, or beneath the glass which supports them, these
crystals, although incapable of producing any colour them-
selves, are yet frequently able to alter the colour which the
mica produces ; for instance, if the mica has produced a blue,
they will, perhaps, alter it to purple, and thus will have the
appearance of purple crystals lying on a blue ground.

Such are the appearances when we examine crystals perfect
in form and structure. But the opposite extreme of the phae-
nomenon is also worth considering, namely, when the crystal-
lization is as irregular as possible, which is the case, for in-
stance, when a few drops of a saline solution are evaporated
by rapid heat. The salt chosen should of course be of a kind
which acts powerfully upon light. When different portions
of such a crystalline film are examined successively, the alter-
nations of colour succeed each other so rapidly and in such a

Mr. H. F. Talbot's Experiments on Light. 325

capricious manner, as to baffle description, and with care it is
often possible to detect five or six different shades of colour
upon some of the very smallest of the crystalline fragments.
These miniature phenomena are often highly curious. Upon
one occasion a solution of some salt was precipitated by al-
cohol in very minute crystals. When the alcohol began to
evaporate, it caused currents in the liquid, which carried the
crystals across the field of view, and at the same time caused
them to revolve round their centres.

The crystals, which were highly luminous in one position,
when their axes were in the proper direction for depolarizing
the light, became entirely dark in the opposite position, thus,
as they rapidly moved onwards, appearing by turns luminous
and obscure, and resembling in miniature the coruscations of
a firefly. It was impossible to view this without admiring the
infinite perfection of nature, that such almost imperceptible
atoms should be found to have a regular structure capable of
acting upon light in the same manner as the largest masses,
and that the element of light itself should obey in such trivial
particulars the same laws which regulate its course through-
out the universe.

In what has preceded I have always supposed the polarizing
eyepiece in such a situation as to darken the field of view. If
we now turn it round 90°, the field of view becomes bright.
But we are now presented with a new set of appearances,
which though not so striking as the last, still have consider-
able interest. Even in this position the apparatus often im-
parts a strong tinge of colour to crystals which are quite
white by ordinary light; and this is sometimes so intense as
to produce complete opacity. As this fact appears to me to
be new, and is particularly striking, I will mention that I have
most frequently observed it with the salts of copper and nickel,
but it also occurs with other salts.

The singularity of this appearance is enhanced by turning
round the polarizing eyepiece ; for when the field of view be-
comes dark, the crystal becomes white and luminous, and
when the field becomes bright, the crystal darkens and becomes
entirely opaque. I have not yet satisfied myself concerning
the cause of this remarkable phaenomenon, which is not in
accordance with the received theory ; but it probably arises
from something peculiar in the chemical nature of these cry-
stals, which causes them to deviate from the ordinary law of
action with respect to the differently coloured rays.

A circumstance which frequently accompanies these experi-
ments is too remarkable to be passed over in silence.

The crystals which form in the liquid under examination are

326 Mr. H. F. Talbot's Experiments on Light.

often observed in a state of rapid growth, increasing in all
their dimensions, while they accurately retain the same geo-
metrical figure. With the polarizing microscope they are
seen to change their tint as they increase in size, and thus,
for instance, it often happens that a crystal which possessed
a red colour at the moment of the first observation, if viewed
again after the lapse of a single minute, may have turned to
green; and again, after the lapse of another minute, it will,
perhaps, have become blue.

I have said enough to show that I regard the polarizing
microscope as an instrument of great promise, and although
I have not had leisure to undertake any very extensive series
of experiments with it, yet I will add two instances by way of
illustration of the manner in which it develops the structure
of transparent bodies, and I will choose for my examples the
sulphate of potash and the acetate of copper, in both of which
I am able to confirm the phenomena announced by preceding
observers.

Sulphate of Potash. — In the yearl819, Sir David Brewster
discovered that the bipyramidal sulphate of potash, which had
been always considered as a simple crystal, was, on the con-
trary, a compound of three others, very curiously jointed to-
gether, in such a way as to produce a six-sided pyramid.

This he ascertained by making a section of the crystal and
viewing a plate of it by polarized light. (See Edinburgh Phi-
losophical Journal, vol. i. p. 6.)

But by proper management I find the sulphate of potash
may be made to crystallize in thin hexagonal plates, and thus
their structure may be examined without the trouble of cutting
them. When a perfect hexagon of this kind is viewed in the
polarizing microscope, it is seen to be divided into six co-
loured triangles, bounded by the six lines which go from the
centre of the hexagon to its angles. There are, however, only
three different colours, because each triangle has always the
same colour with the one opposite to it. It is worth remark
that the six boundary lines are visible even by common light,
resembling small veins or cracks in the crystal.

Acetate of Copper. — In this salt Sir David Brewster detected
the beautiful property of dichroism. (See Phil. Trans, foi-
ls 19, or Brewster's Optics, p. 252.)

By cutting a plate of it from a large crystal, and examining
it by polarized light, he found that it changed its tint from
blue to green according to the position in which the crystal
was held. Now this curious observation receives the most
ample confirmation from the polarizing microscope. I found
the following a convenient method of performing the experi-

Mr. H. F. Talbot's Experiments on Light. 327

ment. A drop of saturated solution of sulphate of copper was
precipitated by ammonia. The precipitate was again dissolved
by more of the alkali, taking care to add no more than was
requisite for that purpose. Some strong aceticacid was then
added, and the whole stirred together with a glass rod, upon
a plate of glass, which was then laid upon the stage of the mi-
croscope. In about half a minute spontaneous crystallization
took place of a very beautiful salt, which I presume to be the
acetate of ammonia and copper, in rhomboids of a deep blue
colour, and very perfect in shape, insomuch that among
many hundreds of them the microscope detected scarcely any
that had any flaw or defect of transparency. In shape these
crystals are not unlike those of common sulphate of copper,
but they are distinguished from them by a decisive character,
namely, their deep blue colour, even when of the very smallest
dimensions: for the crystals of sulphate of copper, when of
this degree of minuteness, are perfectly white. Now, when
the incident light is polarized, it causes a singular change in
these crystals ; for one half of them become green, the other
half acquiring a purer blue than before. But on turning round
the plate of glass that supports them, the blue ones are seen
to change their tint to green, while the green in their turn
become blue: thus exhibiting the dichroism of which Sir David
Brewster was the first discoverer; and exhibiting it, let it be
observed, in crystals too small to be seen with the naked eye,
and without the observer's having the trouble of cutting and
polishing their surfaces.

Potash may be substituted for ammonia in this experiment,
but soda will not answer the purpose.

§ 2. On Photometry.

The subjects of optical inquiry are so diversified and di-
stinct that I have found it convenient to arrange the experi-
ments I am relating under several separate heads, which have
perhaps, little or no connexion with each other. Those men-
tioned in the last section were made lately, while, on the con-
trary, those in the present section, relating to photometry, were
made nine years ago, and should have been published at that
time, except that I wished to render them more worthy of
publication by following up the many other trains of experi-
ment which they suggested. An article in a foreign journal
having recalled my attention to this subject, I will proceed to
give a short account of the view I took of it formerly, and
which I have seen no reason to alter since.

Photometry, or the measurement of the intensity of light,
has been supposed to be liable to peculiar uncertainty. At

328 Mr. H. F. Talbot's Experiments on Light.

least no instrument that has been proposed has met with ge-
neral approval and adoption. I am persuaded, nevertheless,
that light is capable of accurate measurement, and in various
ways; and that the difficulties which stand in the way of ob-
taining a convenient and accurate instrument for photometricai
purposes will ultimately be overcome.

To begin with the most simple considerations which may
serve to guide us in reasoning on this subject, I will select
the experiment well known to every one of whirling round a
glowing coal, which from its rapid motion conveys to the eye
the impression of a continuous fiery circle. The question de-
serves consideration whether the eye receives from this cir-
cular ring exactly the same quantity of light which it received
from the much smaller surface of the coal at rest. There can
be no doubt, as it seems, that such must be the case ; for if
the luminous circle sent more rays to the eye, it would like-
wise send more in every other direction, and thus the apart-
ment would become more illuminated than before, which is
not the fact. If, then, the total quantity of light remains the
same, it follows that its apparent intensity must have dimi-
nished exactly in the same proportion as its apparent area has
been enlarged. For the sake of more accuracy if we confine
our reasoning to a very small portion of the luminous body,
the enlarged area which it seems to occupy is evidently pro-
portional to the circumference of the circle it describes ; there-
fore the preceding argument alleges that the intensity of light
diminishes as the circumference increases. But in the same pro-
portion in which the circumference increases, the time during
which the coal is found in any particular point of the circle
diminishes.

The rapidity of the rotation does not affect the argument.
For instance, if the rotation is in a vertical plane, the time
during which the coal occupies the summit of the circle, com-
pared with the time of one whole revolution, necessarily di-
minishes when the circle grows larger; for the time of its
being so situated bears the same proportion to the whole
time, that the diameter of the moving body (which is con-
stant) bears to the whole circumference through which it
moves. Since, then, these two things— the intensityof light
and the time of the body's remaining in any given part of the
circle — are each inversely proportional to the circumference of
the circle it describes, it follows that they must be directly
proportional to each other ; that is to say, that a regularly in-
termittent luminary whose observations are too frequent and
too transitory for the eye to perceive, loses so much of its ap-
parent brightness from this cause, as is indicated by the pro-

Mr. II. F. Talbot's Experiments on Light. 329

portion between the whole time of observation, and the time
during which it disappears. This seems a very simple law,
and therefore likely to be true ; but such an experiment is
much too inaccurate to be relied upon to establish it. But as
it suggests a very important idea, namely, that time may be
employed to measure the intensity of light, it becomes desir-
able to establish it on solid grounds. And this is easily ac-
complished ; we have only to take a white circle, with one of
its sectors painted black, and make it revolve rapidly. It will
appear, as every one knows, of a uniform gray tint, without any
variation from the centre to the circumference ; and yet, if we
look first at a point near its centre, and afterwards at a point
near its circumference, a much greater portion of the white sur-
face will pass beneath the eye in the latter case than in the
former. But a greater portion of the black surface likewise
passes, and causes a compensation. In every point of the cir-
cle the white and black parts meet the eye during the same
proportion of time, and therefore the tint is uniform through-
out.

This experiment, though very simple and well known,
seems yet well calculated to detect any error in the assumed
law, if it should deviate in the least from the truth ; for such
a deviation would cause a perceptible want of uniformity in
some parts of the circle which the eye would not fail to dis-
cover. I need hardly observe that it would be illogical to
assert a -priori the existence of this law of optics, however
simple and natural it may appear, unless we were perfectly
well acquainted with the circumstances which accompany the
action of light upon the retina, which is very far from being
the case. Its proof can rest upon experiment alone, and by
that it appears to be most satisfactorily established.

Assuming white paper, at least for the present, as our
standard of whiteness, and applying to the revolving circle
black sectors of different angles, we obtain, when they are set
in motion, various gray tints, the obscuration in which is pro-
portional to the angle of the sector ; and therefore, if we make
an assortment of numerous shades of gray paper, and ascer-
tain by direct comparison with the revolving wheel that in
any particular experiment its tint matches one of the papers,
we have only to mark upon the paper the angle of the sector
employed, and we may ever after employ the paper with con-
fidence in questions of a similar kind. According to this no-
tation perfect whiteness would be represented by 0, and per-
fect blackness by 360.

This method may be applied to determine experimentally
the intensity of a polarized ray. We may view through a

Third Series. Vol. 5. No. 29. Nov. 1834. ' 2 U

330 Mr. H. F. Talbot's Experiments on Light.

piece of doubly refracting spar a small white disk placed upon
a black ground. We may cause the two images partially to
overlap each other, and thus have a portion common to both.
This portion will be perfectly white ; but the remaining por-
tions of each image will evidently have exactly one half of
white light. Their tint will therefore agree with that of the
revolving wheel when one half of it is painted black.

But by combining two pieces of spar, images may be form-
ed of variable intensity, according to the position of the axes
of the spar, and they may either be compared with the gray
papers previously graduated, or directly with the indications
of the revolving wheel. Having thus found the proportion
of white light in the images for any given position of this po-
larizing instrument, it may afterwards itself become eminently
employed as a photometer. The colours hitherto used were
white and black, but in order to verify the results more com-
pletely, any two other colours may be chosen, and the mixed
tint arising from their union may be employed instead of the
gray.

Having thus considered the appearance of a whirling disk
containing one black sector, I next made the following varia-
tion in the apparatus. I described a great number of con-
centric circles, and drew a common diameter to them, and
marked off upon each circumference a number of degrees
(reckoned from the diameter) which diminished regularly
from 360° to 0 as the circles grow larger ; i. e. in the smallest
circle I took nearly all the circumference, in the middle circle
I took half the circumference, and in the outer circle the arc
was reduced to nothing. The extremities of all the arcs be-
ing joined together, formed a line belonging to the class of
spirals, but having only one convolution, and bounded by the
common diameter.

(See figure 1.) — This spiral figure was painted black, the
rest of the circle remaining white, and the wheel was then made
to revolve. The result was a gray surface varying gradually
and regularly, in concentric shades, from perfect blackness in
the centre to perfect whiteness in the circumference. I then
chose a number of coloured papers and cut them into circles
of the same size, each of which had this spiral traced upon it,
which I afterwards cut out from the rest of the circle. By
this means, being all of a size, they could be made to replace
each other in a great variety of ways ; for instance, the blue
spiral was put on the yellow circle, and the yellow spiral on
the blue circle. When in motion, I obtained in each case a
surface varying gradually from perfect blue to perfect yellow,
the central part being blue in the first case, and yellow in the

Mr. H. F. Talbot's Experiments on Light. 331

latter. But the most curious part of this experiment was to
observe the neutral tint, through which the colour passed at a
certain point. When this neutral tint offered any singularity
that made it desirable to examine it more particularly, it was
easy, by measuring its
distance from the cen-
tre, to compute how
much of each colour
entered into its compo-
sition ; for instance, if
the diameter of the
wheel, formed of yel-
low and blue, was six
inches, and the tint in
question was two inches
from the centre (sup-
posed blue), it contained
two thirds of blue and
one third of yellow, and
therefore I had only to
make a blue circle, and
place on it a yellow sector of 120°, to obtain infallibly the
same tint over all its surface.

It may be objected to these experiments with revolving disks,
that they afford no assistance when the light of lamps, &c, is
the subject of comparison. But in that case, the principle re-
maining the same, the application of it must be varied, and
we must observe the luminary through a revolving wheel
whose spokes are gradually tapering towards the centre.
If there are twelve spokes each of which forms a sector of
five degrees, their sum is 60 degrees, and the proportion of
this to the whole circle, viz. one sixth, is the degree of obscu-
ration produced by the wheel when rapidly revolving upon all
objects that are seen through it.

If the wheel has eighteen spokes, each of which is a sector
of 10°, their sum is 180°, and therefore, a lamp seen through
them loses one half of its light, and every other luminous ob-
ject the same constant proportion. But since it is requisite
to have the power of producing a variable obscuration, this
may be accomplished by having a second wheel similar to the
first, and placed close to it upon the same axis, so that they
may be capable of being fastened together in any required
position. If they are placed so that their spokes correspond,
the two wheels will, of course, only produce the same effect
that either of them would separately ; but if the spokes of one
correspond to the intervals of the other, they will prevent any

2U2

332 Mr. H. F. Talbot's Experiments on Light

light from passing. Whence it is plain that intermediate posi-
tions may be found which give any precise degree of obscura-
tion that may be desired.

The next step I took in pursuing this inquiry was to re-
verse the first experiment, of a luminous body in motion, by
viewing its image reflected from a revolving mirror. For in-
stance, the image of the sun was made to describe a portion
of a great circle of the heavens by causing the mirror to re-
volve round an axis properly situated. The moving image
thus produced a band of light half a degree broad, and if the
preceding reasoning is true, the intensity of light in the cen-
tral part of this band is diminished in the proportion of the
sun's diameter to 360°, that is, of 1 to 720. The band is
therefore, in its central part, 720 times fainter than the sun's
image at rest, (reflected from the same mirror,) and towards its
borders it is gradually fainter. But as the light will still be
too bright for comparison with terrestrial flames, it must be
diminished further by a second operation of the same kind.
And this may be done in various ways. The most simple
seems to be to employ a screen having an aperture through
which a small portion of the band only can be seen, for in-
stance, half a degree of its length, and then treating this se-
parated portion as a new luminary. By help of a second re-
volving mirror it may be again weakened 720 times, so that
the effect on the eye is then diminished a number of times ex-
pressed by the square of 720, or about half a million, great
care being, however, necessary in this second experiment as
to the position of the observer's eye*. For a photometrical
comparison of objects which are exceedingly unequal in

* As this seems liable to error, except when the second mirror is so
distant from the screen that all its parts may be considered equidistant
from it, the following method may be preferable, though it involves some
mathematical calculation. It has been already remarked, that the sides of
the luminous band or zone are fainter than its central part ; because the
image of the sun's disk takes a shorter time to traverse any point in that
zone the more distant it is from the central line. This want of uniformity
requires that we should determine what is the average brightness of the
zone ; and this resolves itself into the mathematical problem, " What is
the average value of all the chords of a circle, supposing an infinite num-
ber of them to be drawn infinitely near to each other (but equidistant)?
And the answer given to this question by the integral calculus is, that the
average line is equal in length to the quadrantal arc of the circle. This
arc bears to the diameter the ratio of 785 to 1000 nearly, therefore the

78 5

average brightness of the zone is only of the brightness of its central

part.

Now, if by help of a second revolving mirror, we cause the image of this
zone to move in a direction perpendicular to its length, it will be expanded

Mr. H. F. Talbot's Experiments on Light. 333

brightness, I think I have here suggested a method that is
founded upon sound principles.

But here let me be permitted to leave for a moment the
immediate subject of this paper for the purpose of offering a
suggestion relating to the measurement of quantities in va-
rious other branches of natural philosophy. I think the same
method which I have here advanced as leading to a correct
numerical estimation of intense light, is also applicable to the
measurement of very intense heat. It is well known what dis-
crepancy of opinion exists as to the proportion of ordinary
temperatures to those which are very exalted (such, for in-
stance, as that of melted platina). Might we not measure this
heat with an ordinary thermometer, provided we so contrive
the experiment that its exposure to the heat shall be inter-
mittent, and shall only last for an extremely small portion of
the whole time ? To illustrate this idea, let us suppose a red-
hot cannon ball suspended near the edge of a rapidly re-
volving wheel. If a thermometer were fixed on the circum-
ference of the wheel, it would be only exposed to the influence
of the high temperature during a small part (let us suppose,
for example's sake, a hundredth part) of its revolution. If,
therefore, it was observed to mount five degrees, we might
fairly argue that it would have sustained an increase of tem-
perature of 500°, if it had remained stationary at the point
nearest to the ball.

It is true, that in this form the experiment would be very
inaccurate, owing to the cooling power of the atmosphere on
the revolving thermometer and other causes, therefore I only
mention it for the sake of illustration ; or both the healed
body and the thermometer might be at rest, and a rotatory
screen might intervene between them, having an aperture of
given dimension, during the passage of which the thermo-
meter would be affected by the heat, but not at other times.

If there is any truth in the preceding argument, as I trust
there is, it offers a method (and perhaps the only possible
one of subjecting to numerical comparison some qualities of

into a surface uniform in light, which will have , — L X , that is.

(7 20)* 1000 *

about of the brightness of the sun ; that is, speaking accurately,

not of the sun himself, but of his image reflected successively from both
mirrors when at rest. It is, however, to be observed, that the velocities
of the two mirrors must not be equal, nor in any simple ratio to one an-
other, otherwise their effect would be different from what is here contem-
plated.

334 Dr. Faraday's Experimental Researches in Electricity.

bodies which have never, I believe, been even attempted to be
measured, such as the intensity of odours, &c. ; for this prin-
ciple seems to have a general application. We may always
find means of dividing the experiment into minute intervals
of time, and we may cause that quality of the body which
we wish to estimate the intensity of to act upon our senses
or upon our instruments, only during a certain number of
those intervals, but regularly and rapidly recurring in a stated
order.

XLV. Experimental Researches in Electricity. — Seventh
Series. By Michael Faraday, D.C.L. F.R.S. Fullerian
Prof. Chem. Royal Institution, Corr. Memb. Royal and Imp.
Acadd. of Sciences, Paris, Petersburgh, Florence, Copenhagen,
Berlin, fyc.

[Continued from p, 264.]

If vii. On the definite Nature and Extent of Electro-chemical
Decomposition.

783. TN the third series of these Researches, after proving
-*■ the identity of electricities derived from different
sources, and showing, by actual measurement, the extraor-
dinary quantity of electricity evolved by a very feeble voltaic
arrangement (371. 376.), I announced a law, derived from
experiment, which seemed to me of the utmost importance to
the science of electricity in general, and that branch of it de-
nominated electro-chemistry in particular. The law was ex-
pressed thus: The chemical power of a current of electricity is
in direct proportion to the absolute quantity of electricity
which passes (377.)»

784. In the further progress of the successive investigations,
I have had frequent occasion to refer to the same law, occa-
sionally in circumstances offering powerful corroboration of its
truth (456.504.505.); and the present series already supplies
numerous new cases in which it holds good (704. 722. 726. 732.).
It is now my object to consider this great principle more
closely, and to develope some of the consequences to which it
leads. That the evidence for it may be the more distinct and
applicable, I shall quote cases of decomposition subject to as
few interferences from secondary results as possible, effected
upon bodies very simple, yet very definite in their nature.

785. In the first place, I consider the law as so fully esta-
blished with respect to the decomposition of water, and under
so many circumstances which might be supposed, if anything
could, to exert an influence over it, that I may be excused

Definite Chemical Action of Electricity, 335

entering into further detail respecting that substance, or even
summing up the results here (732.). I refer, therefore, to the
whole of the subdivision of this series of Researches which
contains the account of the volta-electrometer,

786. In the next place, 1 also consider the law as esta-
blished with respect to muriatic acid by the experiments and
reasoning already advanced, when speaking of that substance,
in the subdivision respecting primary and secondary results
(758, &c).

787. I consider the law as established also with regard to
hydriodic acid by the experiments and considerations already
advanced in the preceding division of this series of Researches
(767. 768.).

788. Without speaking with the same confidence, yet from
the experiments described, and many others not described,
relating to hydro-fluoric, hydro-cyanic, ferro-cyanic, and
sulpho-cyanic acids (770. 77 i. 772.), and from the close ana-
logy which holds between these bodies and the hydro-acids
of chlorine, iodine, bromine, &c, 1 consider these also as
coming under subjection to the law, and assisting to prove its
truth.

789. In the preceding cases, except the first, the water is
believed to be inactive ; but to avoid any ambiguity arising
from its presence, I sought for substances from which it should
be absent altogether; and, taking advantage of the law of
conduction already developed (380. &c), soon found abund-
ance, amongst which protochloride of tin was first subjected
to decomposition in the following manner. A piece of platina
wire had one extremity coiled up into a small knob, and
having been carefully weighed, was sealed hermetically into a
piece of bottle-glass tube, so that the knob should be at the
bottom of the tube within (fig. 13.). The tube was suspended
by a piece of platina wire, so that the heat of a spirit-lamp
could be applied to it. Recently fused proto-chloride of tin
was introduced in sufficient quantity to occupy, when melted,
about one half of the tube ; the wire of the tube was connected
with a volta-electrometer (711.), which was itself connected
with the negative end of a voltaic battery ; and a platina wire
connected with the positive end of the same battery was
dipped into the fused chloride in the tube ; being, however,
so bent, that it could not by any shake of the hand or ap-
paratus touch the negative electrode at the bottom of the ves-
sel. The whole arrangement is delineated fig. 14.

790. Under these circumstances the chloride of tin was
decomposed : the chlorine evolved at the positive electrode
formed bichloride of tin (779.), which passed away in fumes,

336 Dr. Faraday's Experimental Researches in Electricity.

and the tin evolved at the negative electrode combined with
the platina, forming an alloy, fusible at the temperature to
which the tube was subjected, and therefore never occasioning
metallic communication entirely through the decomposing
chloride. When the experiment had been continued so long
as to yield a reasonable quantity of gas in the volta-electro-
meter, the battery connexion was broken, the positive elec-
trode removed, and the tube and remaining chloride allowed
to cool. When cold, the tube was broken open, the rest of
the chloride and the glass being easily separable from the
platina wire and its button of alloy. The latter when washed
was then reweighed, and the increase gave the weight of the
tin reduced.

791. I will give the particular results of one experiment, in
illustration of the mode adopted in this and others, the results
of which I shall have occasion to quote. The negative elec-
trode weighed at first 20 grains ; after the experiment it, with
its button of alloy, weighed 23*2 grains. The tin evolved by
the electric current at the cathode weighed, therefore, 3*2
grains. The quantity of oxygen and hydrogen collected in
the volta-electrometer = 3-85 cubic inches. As 100 cubic
inches of oxygen and hydrogen, in the proportions to form
water, may be considered as weighing 12*92 grains, the 3 85
cubic inches would weigh 0*49742 of a grain; that being,
therefore, the weight of water decomposed by the same elec-
tric current as was able to decompose such weight of proto-
chloride of tin as could yield 3*2 grains of metal. Now
0*49742 : 3*2 : : 9 the equivalent of water is to 57*9, which
should therefore be the equivalent of tin, if the experiment
had been made without error, and if the electro-chemical de-
composition is in this case also definite. In some chemical
works 58 is given as the chemical equivalent of tin, in others
57*9. Both are so near to the result of the experiment, and
the experiment itself is so subject to slight causes of variation
(as from the absorption of gas in the volta-electrometer (71 6.),
&c), that the numbers leave little doubt of the applicability
of the law of definite action in this and all similar cases of
electro-decomposition.

792. It is not often I have obtained an accordance in num-
bers so near as that I have just quoted. Four experiments
were made on the protochloride of tin, the quantities of gas
evolved in the volta-electrometer being from 2*05 to 10*29
cubic inches. The average of the four experiments gave 58*53
as the electro-chemical equivalent for tin.

793. The chloride remaining after the experiment, was
pure protochloride of tin ; and no one can doubt for a mo-

Definite Chemical Action of Electricity. 337

merit that the equivalent of chlorine had been evolved at the
anode, and having formed bichloride of tin as a secondary re-
sult, had passed away.

794. Chloride of lead was experimented upon in a manner
exactly similar, except that a change was made in the nature
of the positive electrode ; for as the chlorine evolved at the
anode forms no perchloride of lead, but acts directly upon the
platina, if that metal be used, it produces a solution of chlo-
ride of platina in the chloride of lead; in consequence of
which a portion of platina can pass to the cathode, and will
produce a vitiated result. I therefore sought for, and found
in plumbago, another substance, which could be used safely
as the positive electrode in such bodies, as chlorides, iodides,
&c. The chlorine or iodine does not act upon it, but is
evolved in the free state; and the plumbago has no reaction,
under the circumstances, upon the fused chloride or iodide in
which it is plunged. Even if a few particles of plumbago
should separate by the heat or the mechanical action of the
evolved gas, they can do no harm in the chloride.

795. The mean of three experiments gave the number of
100*85 as the equivalent for lead. The chemical equivalent
is 103*5. The deficiency in my experiments, I attribute to
the solution of part of the gas (716.) in the volta-electrometer;
but the results leave no doubt on my mind that both the lead
and the chlorine are, in this case, evolved in definite quantities
by the action of a given quantity of electricity (814. &c).

796. Chloride of Antimony. — It was in endeavouring to ob-
tain the electro-chemical equivalent of antimony from the
chloride that I found reasons for the statement I have made
respecting the presence of water in it in an earlier part of
these Researches (690. 693. &c).

797. I endeavoured to experiment upon the oxide of lead
obtained by fusion and ignition of the nitrate in a platina cru-
cible, but found great difficulty, from the high temperature
required for perfect fusion, and the powerful fluxing qualities
of the substance. Green glass tubes repeatedly failed. I at
last fused the oxide in a small porcelain crucible, heated fully
in a charcoal fire ; and as it was essential that the evolution
of the lead at the cathode should take place beneath the sur-
face, the negative electrode was guarded by a green glass
tube, fused around it in such a manner as to expose only the
knob of platina at the lower end (fig. 15.), so that it could be
plunged beneath the surface, and thus exclude contact of air
or oxygen with the lead reduced there. A platina wire was
employed for the positive electrode, that metal not being sub-

Third Scries. Vol. 5. No. 29. Nov. 1834. 2 X

S38 Dr. Faraday's Experimental Researches in Electricity.

ject to any action from the oxygen evolved against it. The
arrangement is given fig. 16.

798. In an experiment of this kind the equivalent for the
lead came out 93*17, which is very much too small. This, I
believe, was because of the small interval between the positive
and negative electrodes in the oxide of lead, so that it was not
unlikely that some of the froth and bubbles formed by the oxy-
gen at the anode should occasionally even touch the lead re-
duced at the cathode, and re-oxidize it. When I endeavoured
to correct this by having more litharge, the greater heat re-
quired to keep it all fluid caused a quicker action on the cru-
cible, which was soon eaten through, and the experiment
stopped.

799. In one experiment of this kind I used borate of lead
(408. 673.). It evolves lead, under the influence of the elec-
tric current, at the anode, and oxygen at the cathode; and as
the boracic acid is not either directly (4-08.) or incidentally de-
composed during the operation, I expected a result dependent
on the oxide of lead. The borate is not so violent a flux as
the oxide, but it requires a higher temperature to make it
quite liquid; and if not very hot, the bubbles of oxygen cling
to the positive electrode, and retard the transfer of electricity.
The number for lead came out 101*29, which is so near
to 103*5 as to show that the action of the current had been
definite.

800. Oxide of Bismuth, — I found this substance required
too high a temperature, and acted too powerfully as a flux, to
allow of any experiment being made on it, without the appli-
cation of more time and care than I could give at present.

801. The ordinary protoxide of antimony, which consists
of one proportional of metal and one and a half of oxygen,
was subjected to the action of the electric current in a green
glass tube (789.), surrounded by a jacket of platina foil, and
heated in a charcoal fire. The decomposition began and
proceeded very well at first, apparently indicating, according
to the general law (679. 697.), that this substance was one
containing such elements and in such proportions as made it
amenable to the power of the electric current. This effect
I have already given reasons for supposing may be due to the
presence of a true protoxide, consisting of single proportionals
(696. 693.). The action soon diminished, and finally ceased,
because of the formation of a higher oxide of the metal at the
positive electrode. This compound, which was probably the
peroxide, being infusible and insoluble in the protoxide,
formed a crystalline crust around the positive electrode;

Definite Chemical Action of Electricity, 339

and thus insulating it, prevented the transmission of the elec-
tricity. Whether if it had been fusible and still immiscible it
would have decomposed, is doubtful, because of its departure
from the required composition (697.)* It was a very natural
secondary product at the positive electrode (779.). On open-
ing the tube it was found that a little antimony had been se-
parated at the negative electrode; but the quantity was too
small to allow of any quantitative result being obtained.

802. Iodide of Lead. — This substance can be experimented
with in tubes heated by a spirit-lamp (789.) ; but I obtained
no good results from it, whether I used positive electrodes of
platina or plumbago. In two experiments the numbers for
the lead came out only 75*46 and 73*45, instead of 103*5.
This I attribute to the formation of a periodide at the positive
electrode, which dissolving in the mass of liquid iodide, came
in contact with the lead evolved at the negative electrode, and
dissolved part of it, becoming itself again protiodide. Such
a periodide does exist; and it is very rarely that the iodide of
lead formed by precipitation, and well washed, can be fused
without evolving much iodine, from the presence of this per-
compound ; nor does crystallization from its hot aqueous so-
lution free it from this substance. Even when a little of the
protiodide and iodine are merely rubbed together in a mortar,
a portion of the periodide is formed. And though it is de-
composed by being fused and heated to dull redness for a few
minutes, and the whole reduced to protiodide, yet that is not
at all opposed to the possibility, that a little of that which is
formed in great excess of iodine at the anode, should be car-
ried by the rapid currents in the liquid into contact with the
cathode.

803. This view of the results was strengthened by a third
experiment, where the space between the electrodes was in-
creased to one third of an inch ; for now the interfering effects
were much diminished, and the number of the lead came out
89*04; and it was fully confirmed by the results obtained in
the cases of transfer to be immediately described (818.).

The experiments on iodide of lead, therefore, offer no ex-
ception to the general law under consideration, but, on the
contrary, may, from general considerations, be admitted as in-
cluded in it.

804. Protiodide of Tin. — This substance, when fused (402.),
conducts and is decomposed by the electric current, tin is
evolved at the anode, and periodide of tin as a secondary re-
sult (779. 790.) at the cathode. The temperature required
for its fusion is too high to allow of the production of any re-
sults fit for weighing.

2X2

31-0 Dr. Faraday's Experimental Researches in Electricity.

805. Iodide of potassium was subjected to electrolytic action
in a tube, fig. 13. (789.). The negative electrode was a
globule of lead, and I hoped in this way to retain the potas-
sium, and obtain results that could be weighed and compared
with the volta-electrometer indication ; but the difficulties de-
pendent upon the high temperature required, the action upon
the glass, the fusibility of the platina induced by the presence
of the lead, and other circumstances, prevented me from ob-
taining such results. The iodide was decomposed with the
evolution of iodine at the anode, and of potassium at the cat-
hode, as in former cases.

806. In some of these experiments several substances were
placed in succession, and decomposed simultaneously by the
same electric current; thus, protochloride of tin, chloride of
lead, and water, were thus acted on at once. It is needless
to say that the results were comparable, the tin, lead, chlo-
rine, oxygen, and hydrogen evolved being definite in quantity
and electro-chemical equivalents to each other.

807. Let us turn to another kind of proof of the definite
chemical action of electricity. If any circumstances could be
supposed to exert an influence over the quantity of the matters
evolved during electrolytic action, one would expect them
to be present when electrodes of different substances, and
possessing very different chemical affinities for the evolving
bodies, were used. Platina has no power in dilute sulphuric
acid of combining with the oxygen at the anode, though the
latter be evolved in the nascent state against it. Copper, on
the other hand, immediately unites to the oxygen, as the elec-
tric current sets it free from the hydrogen ; and zinc is not
only able to combine with it, but can, without any help from
the electricity, abstract it directly from the water, at the same
time setting torrents of hydrogen free. Yet in cases where
these three substances were used as the positive electrodes in
three similar portions of the same dilute sulphuric acid, spe-
cific gravity 1*336, precisely the same quantity of water was
decomposed by the electric current, and precisely the same
quantity of hydrogen set free at the cathodes of the three so-
lutions.

808. The experiment was made thus. Portions of the di-
lute sulphuric acid were put into three basins. Three volta-
electrometer tubes, of the form figg. 5, 7. were filled with the
same acid, and one inverted in each basin (707.). A zinc
plate, connected with the positive end of a voltaic battery,
was dipped into the first basin, forming the positive electrode
there, the hydrogen, which was abundantly evolved from it
by the direct action of the acid, being allowed to escape. A

Definite Chemical Action of Electricity. 341

copper plate, which dipped into the acid of the second basin,
was connected with the negative electrode of the frst basin ;
and a platina plate, which dipped into the acid of the third
basin, was connected with the negative electrode of the second
basin. The negative electrode of the third basin was con-
nected with a volta-electrometer (711.), and that with the
negative end of the voltaic battery.

809. Immediately that the circuit was complete, the electro-
chemical action commenced in all the vessels. The hydrogen
still rose in, apparently, undiminished quantities from the po-
sitive zinc electrode in the first basin. No oxygen was evolved
at the positive copper electrode in the second basin, but a
sulphate of copper was formed there; whilst in the third basin
the positive platina electrode evolved pure oxygen gas, and
was itself unaffected. But in all the basins the hydrogen li-
berated at the negative platina electrodes was the same in
quantity, and the same with the volume of hydrogen evolved
in the volta-electrometer, showing that in all the vessels the
current had decomposed an equal quantity of water. In this
trying case, therefore, the chemical action of electricity proved
to be 'perfectly definite.

810. A similar experiment was made with muriatic acid
diluted with its bulk of water. The three positive electrodes
were zinc, silver, and platina; the first being able to separate
and combine with the chlorine without the aid of the current;
the second combining with the chlorine only after the current
had set it free ; and the third rejecting almost the whole of it.
The three negative electrodes were, as before, platina plates
fixed within glass tubes. In this experiment, as in the former,
the quantity of hydrogen evolved at the cathodes was the same
for all, and the same as the hydrogen evolved in the volta-
electrometer. I have already given my reasons for believing
that in these experiments it is the muriatic acid which is di-
rectly decomposed by the electricity (764-.); and the results
prove that the quantities so decomposed are perfectly definite
and proportionate to the quantity of electricity which has
passed.

811. In this experiment the chloride of silver formed in the
second basin retarded the passage of the current of electricity,
by virtue of the law of conduction before described (394-.), so
that it had to be cleaned off four or five times during the
course of the experiment; but this caused no difference be-
tween the results of that vessel and the others.

812. Charcoal was used as the positive electrode in both
sulphuric and muriatic acids (808. 810.); but this change
produced no variation of the results. A zinc positive elec-

34-2 Dr. Faraday's Experimental Researches in Electricity.

trode, in sulphate of soda or solution of common salt, gave
the same constancy of operation.

813. Experiments of a similar kind were then made with
bodies altogether in a different state, i. e. with fused chlorides,
iodides, &c. I have already described an experiment with
fused chloride of silver, in which the electrodes were of me-
tallic silver, the one rendered negative becoming increased
and lengthened by the addition of metal, whilst the other was
dissolved and eaten away by its abstraction. This experiment
was repeated, two weighed pieces of silver wire being used as
the electrodes, and a volta-electrometer included in the cir-
cuit. Great care was taken to withdraw the negative elec-
trode so regularly and steadily that the crystals of reduced
silver should not form a metallic communication beneath the
surface of the fused chloride. On concluding the experiment
the positive electrode was re-weighed, and its loss ascertained.
The mixture of chloride of silver, and metal, withdrawn in
successive portions at the negative electrode, was digested in
solution of ammonia, to remove the chloride, and the metallic
silver remaining also weighed : it was the reduction at the cat-
hode9 and exactly equalled the solution at the anode; and each
portion was as nearly as possible the equivalent to the water
decomposed in the volta-electrometer.

814. The infusible condition of the silver at the tempera-
ture used, and the length and ramifying character of its cry-
stals, render the above experiment difficult to perform, and
uncertain in its results. I therefore wrought with a chloride
of lead, using a green glass tube, formed as in fig. 17. A
weighed platina wire was fused into the bottom of a small
tube, as before described (789.). The tube was then bent to
an angle, at about half an inch distance from the closed end;
and the part between the angle and the extremity being soft-
ened, was forced upward, as in the figure, so as to form a
bridge, or rather separation, producing two little depressions
or basins a, b9 within the tube. This arrangement was sus-
pended by a platina wire, as before, so that the heat of a
spirit-lamp could be applied to it, such inclination being given
to it as would allow all air to escape during the fusion of the
chloride of lead. A positive electrode was then provided, by
binding up the end of a platina wire into a knob, and fusing
about twenty grains of metallic lead on to it, in a small closed
tube of glass, which was afterwards broken away. Being so
furnished, the wire with its knob was weighed, and the weight
recorded.

815. Chloride of lead was now introduced into the tube,
and carefully fused. The leaded electrode was also intro-

Definite Chemical Action of Electricity, 343

duced; after which the metal, at its extremity, soon melted.
In this state of things the tube was filled up to c with melted
chloride of lead ; the end of the electrode to be rendered
negative was in the basin b, and the electrode of melted lead
was retained in the basin a, and, by connexion with the
proper conducting wire of a voltaic battery, was rendered
positive. A volta-electrometer was included in the circuit.

816. Immediately upon the completion of the communica-
tion with the voltaic battery, the current passed, and decom-
position proceeded. No chlorine was evolved at the positive
electrode ; but as the fused chloride was transparent, a button
of alloy could be observed gradually forming and increasing
in size at b, whilst the lead at a could also be seen gradually
to diminish. After a time, the experiment was stopped; the
tube allowed to cool, and broken open ; the wires, with their
buttons, cleaned and weighed ; and their change in weight
compared with the indication of the volta-electrometer,

817. In this experiment the positive electrode had lost just
as much lead as the negative one had gained (795.), and the
loss or gain was very nearly the equivalent of the water de-
composed in the volta-electrometer, giving for lead the num-
ber 101*5. It is therefore evident, in this instance, that caus-
ing a strong affinity, or no affinity, for the substance evolved at
the anode, to be active during the experiment (807.), produces
no variation in the definite action of the electric current.

818. A similar experiment was then made with iodide of
lead, and in this manner all confusion from the formation of
a periodide avoided (803.). No iodine was evolved during the
whole action, and finally the loss of lead at the anode was the
same as the gain at the cathode, the equivalent number, by
comparison with the result in the volta-electrometer, being
103-5.

819. Then protochloride of tin was subjected to the electric
current in the same manner, using, of course, a tin positive
electrode. No bichloride of tin was now formed (779. 790.).
On examining the two electrodes, the positive had lost pre-
cisely as much as the negative had gained; and by comparison
with the volta-electrometer, the number for tin came out 59.

820. It is quite necessary in these and similar experiments
to examine the interior of the bulbs of alloy at the ends of
the conducting wires; for occasionally, and especially with
those which have been positive, they are cavernous, and con-
tain portions of the chloride or iodide used, which must be
removed before the final weight is ascertained. This is more
usually the case with lead than tin.

821. All these facts combine into, I think, an irresistible

344 Account of the new Observatory at Gbttingen.

mass of evidence, proving the truth of the important proposi-
tion which I at first laid down, namely, that the chemical power
of a current of electricity is in direct proportion to the absolute
quantity of electricity which passes (377. 783.). They prove,
too, that this is not merely true with one substance, as water,
but generally with all electrolytic bodies; and, further, that
the results obtained with any one substance do not merely
agree amongst themselves, but also with those obtained from
other substances^ the whole combining together into one series
of definite electro-chemical actions (505.). I do not mean to
say that no exceptions will appear : perhaps some may arise,
especially amongst substances existing only by weak affinity ;
but I do not expect that any will seriously disturb the result
announced. If, in the well considered, well examined, and,
I may surely say, well ascertained doctrines of the definite
nature of ordinary chemical affinity, such exceptions occur, as
they do in abundance, yet, without being allowed to disturb
our minds as to the general conclusion, they ought also to be
allowed if they should present themselves at this, the opening
of a new view of electro-chemical action ; not being held up
as obstructions to those who may be engaged in rendering
that view more and more perfect, but laid aside for a while,
in hopes that their perfect and consistent explanation will
finally appear.

[To be continued.]

XL VI. Account of the new Observatory for Magnetic Obser-
vations at Gbttingen*,
"V17*E are indebted to the munificence of Government for
" a new institution, devoted to an important part of na-
tural philosophy, namely, an Observatory, erected for magnetic
observations and measurements. Although the building was
commenced last autumn, and the interior arrangements so far
advanced at the beginning of this year that daily observations
could be made in it ever since that period, we have forborne
giving an account of it in this publication, as we wished to
add at the same time some of the results of the observations.
The magnetical apparatuses, constructed on new principles,
and placed, in 1832, in our astronomical observatory, have
been fully described in a former Numberf, from which it will
be seen that very exact results may be obtained by their use.

* From the Gottingische gelehrte Anzeigen for August 1834.

•j- A translation of Prof. Gauss's memoir in which these apparatus are
described, will be found in our report of the proceedings of the Royal So-
ciety for Feb. 14,1833: Lond. and Edinb. Phil. Mag. vol. ii. p.291.— Edit.

Account of the new Magnetical Observatory at Gottifigen. 345

But to render this exactness complete, the apparatuses were
required to be made on a larger scale; and, to procure for
the results a perfect freedom from extraneous influences, it
was also necessary to erect a building entirely free from
iron.

The magnetic observatory stands in an open space about
a hundred paces west of the astronomical one, and forms an
oblong square, placed due north and south, of 32 Paris feet
in length, by 15 in breadth, with two projections on the
longer sides. Of these the western forms the entrance, and
also serves for certain observations as an extension of the
space within ; while the eastern, which is perfectly parted off
from that principal apartment, is appropriated to the watch-
man of the observatory. Everything in the building usually
made of iron, such as locks, hinges, window linings, nails, &c,
is made here of copper. Drafts are as much as possible pre-
vented. The height of the apartment is 10 feet. The mag-
netic apparatus being essentially the same as that alluded
to above, we shall here confine ourselves to merely point-
ing out the differences. The magnetic bar is made of Uslar
cast steel, which is particularly fit for magnetic observations ;
and it is frequently replaced by another, both being very nearly
of the same size, viz. 610 millimetres in length, 37 in breadth,
and 10 in thickness, having a weight of nearly four pounds.
The mirror is 75 millimetres broad and 50 high. The suspen-
sion of the rod from the ceiling is effected by means of a 200-
fold untwisted silk thread 7 feet long ; but the circle of torsion
is not, as before, at the upper, but at the lower, end of the
thread, and so connected with the little skiff bearing the rod
as to turn with it. Silk threads, as has been observed in Mr.
Gauss's treatise, Intensitas Vis magneticce terrestris, (p. 19,)
have the great advantage over metallic ones that their
power of torsion is but small : in the present thread it is only
the nine hundredth part of the horizontal power of direction
of the magnetic rod ; whilst the twisting power of a metallic
thread of the same strength for bearing would be about ten times
as great. On the other hand, silk threads, especially if their
power of supporting does not much exceed the weight attach-
ed to them, have the inconvenience of considerably stretching
during the first weeks, or by a great increase of weight. This
inconvenience has been here removed by an ingenious suspen-
sion apparatus, suggested by Professor Webei*, fastened to
the ceiling, and by which the thread may be wound up as much
as necessary, without changing its place; while at the same
time, this apparatus itself can be shifted about the ceiling, if,
in the course of time, a removal should become necessary, by

Third Series. Vol. 5. No. 29. Nov. 1834. 2 Y

346 Account of the new Magnetical Observatory at Gottingcn.

a variation in the magnetic declination. The theodolite has
hitherto been standing on a very solid wooden pedestal on a
stone foundation ; and from its position may be seen, through
the northern window, one of the steeples of the town, the
azimuth of which has been exactly determined. A delicate
vertical line on the opposite northern wall is the only mark
by which the unmoved position of the theodolite is rectified.
A scale , 4 feet long, divided into millimetres, is used in
common; but for some observations it is changed for one
2 metres long. The value of a division of the scale is
21"*3. For night observations the scale has been hitherto
strongly lighted with wax candles; but in future Argand
lamps will be used instead. One of the principal uses of the
apparatus now is to determine with the utmost exactness the
magnetic declination, and its variations in different hours of
the day, months, and years. The noting takes place twice
every day at fixed hours, viz. at 8 in the morning and 1 p.m.,
with which times, in a regular course of daily variations, the
smallest and the greatest declination, at least during the
first months of the year, pretty nearly coincide. This man-
ner of noting exactly at the same hours, (instead of waiting for
the minimum and maximum of every day,) has been preferred
for important reasons, which need not be entered upon in this
place. The noting was begun as early as the 1st of January,
but because at first the thread of suspension, being too weak,
required, in consequence of its gradual stretching, to be fre-
quently wound up, which produced rather considerable vari-
ations in the zero point of torsion, — at first not sufficiently
noticed, — the [observations of the] first two months and a
half have been excluded. The mean values of the western
declination of the magnetic needle have since been as follows:

March, second half

April

May

June

July

8 o'Clock a.m.

18° 38' 16"*0
36 6*9

36 28 -2

37 40-7
37 57*5

1 o'Clock p.m.

18°46'40H

47 3-8
47 15-4

47 59-5

48 19-0

Moreover, on certain days of the year the variations of the
declination are observed uninterruptedly for 44 hours, at
short intervals. For this purpose those days were chosen
which several years ago were fixed on by M. de Humboldt,
and on which by agreement similar observations are noted

Account of the new Magnetical Observatory at Gottingen. 347

with Gambey's apparatus in other places, some of which are
very remote 'from each other. Till now, such observations have
been made here three times, viz. on the 20 — 21 March, 4 — 5
May, and 21 — 22 June; and the persons engaged in it were,
besides Mr. Gauss, the Professors Weber and Ulrich, Doctors
Weber, Goldschmidt, and Listing, and Messrs. Sartorius,
Deahna, and Wilh. Gauss. The object of these observations
is, partly to obtain gradually a fuller acquaintance with the re-
gular course [of the phenomena], partly to discover the nature
of the very great anomalies occurring at times, especially with
aurora) boreales, by contemporaneous observations in different
places. The notings here were made in March, at intervals of
20 minutes, and even of half that time; in May, every 10 and
even 5 minutes; and in June, always at intervals of 5 minutes.
Some anomalies were observed, particularly a few very great
ones in the night of the 20 to 21 March; very considerable
and numerous ones in the night of the 4 — 5 May; and some
decided, though not great ones, on the 21 June, whilst the
22nd of that month was exceedingly regular. We have as
yet heard nothing of the results of corresponding observa-
tions instituted at the suggestion of M. de Humboldt, except
of those made at Berlin on the 21 — 22 March, which were,
however, only noted from hour to hour, and could, therefore,
furnish no satisfactory results. Still they contained an indica-
tion of the anomalies noted and pursued at Gottingen. On the
other hand corresponding observations were made very fully
on the 4 — 5 May, by Mr. Sartorius, in a country house in
Bavaria, a few miles south of Meiningen, with an apparatus
on the same principle as that of our observatory, although
smaller; which produced a most wonderful agreement with
the great anomalies observed here, as to time, magnitude and
variations, so that in their noting they appear almost copies
of each other in all the mixed figures produced by those ano-
malies. An equally beautiful result was obtained by corre-
sponding observations made in Berlin on the 21 — 22 by Pro-
fessor Encke, assisted by Messrs. PoggendorfF, Madler, and
Wolfers, for the first time with an apparatus like ours, al-
though likewise smaller. Also there were no other anomalies
but those observed here ; but these were almost exact copies ;
and the same was shown by the observations made at that
time at Francfort by Mr. Sartorius. These results may al-
ready be considered as a beautiful effect of preconcerted ob-
servations, since they clearly show that both the small and great
anomalies in the magnetic needle, which are observed some-
times at very short intervals, must be ascribed to causes by
no means local, but powerful ones and operating at great

2 Y 2

34-8 Account of the nem Magnetical Observatory at Gottingcn.

distances ; a fact which had indeed been noticed before in
cases of very great irregularities in connexion with auroras
boreales. It is therefore to be expected that, as the participa-
tion in these preconcerted observations with this both conve-
nient and exact apparatus increases (for which there are al-
ready the best prospects), we shall obtain very remarkable and
comprehensive solutions of these very singular and till now
inexplicable phaenomena.

Similar observations have frequently been made here at other
times also, from which sometimes very striking anomalies have
resulted. Thus, for instance, on the 14-th January, in the even-
ing between 8 and 9 o'clock, the declination decreased, within a
quarter of an hour, by 13 minutes, with the greatest regularity,
and then gradually returned to its former position. Such ob-
servations, however, can produce no further results, since,
without a preconcerted arrangement, corresponding observa-
tions are very seldom to be expected.

From time to time also the experiments relative to the deter-
mination of the absolute intensity of terrestrial magnetism will
be repeated at the observatory ; but as they require various
preparations to perform them with the greatest exactness, the
first could not be made till the month of July. Three de-
terminations with different bars gave the following results :

July 17th 1-7743

20th..., 1-7740

21st 1-7761

as the value of the horizontal power by which, as in the earlier
determinations with smaller bars, the second of time, the mil-
limetre, and the milligramme form the foundation as units.

The new apparatus in the magnetical observatory has also
been adapted for making electro-magnetic observations and
measurements, in a similar manner as in the astronomical obser-
vatory. The suspended magnetic rod is surrounded by a mul-
tiplier consisting of 200 circumvolutions, the construction of
which permitted the use of uncovered wire : the length of the
wire is 11 00 feet. With the help of a very simply constructed
commutator, the observer may, without taking his eye from
the telescope, reverse the direction of, or entirely interrupt,
the galvanic current.

Nor can we omit mentioning on this occasion an apparatus
on a grand and hitherto unique scale, connected with the ap-
paratuses just described, and which we owe to our Professor
Weber. This gentleman had during the last year conducted
a double line of wires from the cabinet of natural philosophy
over the houses of the town to the astronomical observatory.
These are now continued to the magnetical observatory, thus

Mi*. Faraday on certain Magneto- electric Phenomena. 349

forming a chain by which the galvanic current, including the
multipliers attached to each end of the chain, has to run
through a length of wire of nearly 9000 feet. The wire is mostly
copper, of the thickness known in trade as number 3, and of
which a length of one metre weighs 8 grammes. The wire
of the multiplier in the magnetical observatory is of plated
copper number 14, of which one gramme gives 2'6 metres.
This arrangement is likely to produce the most interesting re-
sults. It is wonderful how a single pair of plates placed at
the other extremity immediately impart to the magnetic rod
a motion equal to considerably more than a thousand divisions
of the scale. But what is still more remarkable is, that a pair
of plates, of perhaps no more than one inch in diameter,
will produce, with the application of mere spring or distilled
water, an effect not much less than that produced by a very
large pair of plates with the application of a strong acid.
This circumstance, however, is after all not surprising, as it
only tends to confirm the beautiful theory first established by
Ohm. On the other hand, by adding to the number of the
pairs of plates the effect increases, and almost in exact pro-
portion to it. The facility and certainty by which, through
the means of the commutator, the current and the movement
of the needle dependent on it are commanded, suggested
the idea of trying telegraphic experiments with the apparatus,
which have perfectly succeeded with whole words, and even
short phrases. Nor is there a doubt that by this means tele-
graphic communications might be formed between towns many
miles apart ; but this is, of course, not the place where we
could enter on a further development of this subject.

XL VI I. On the Magneto- electric Spark and Shock, and on
a peculiar Condition of Electric and Magneto-electric In-
duction. By Michael Faraday, Esq., D.C.L., F.R.S., §c.

To Richard Phillips, Esq., F.R.S., fyc.
My dear Sir,
TF you think well of the following facts and reasoning, you
A will, perhaps, favour them with a place in the Philosophical
Magazine.

When I first obtained the magneto- electric spark*, it was
by the use of a secondary magnet, rendered for the time active
by a principal one ; and this has always, as far as I am aware,
been the general arrangement. My principal was an electro-
magnet; Nobili's wTas, I believe, an ordinary magnet; others

* Philosophical Transactions, 1832, p. 132. [See also Phil. Mag. and
Annals, N.S. vol. xi. p. 401, &c— Edit.]

350 Mr. Faraday on the Magneto-electric Spark and Shock,

have used the natural magnet, but in all cases the secondary
magnet was a piece of soft iron.

The spark is never the electricity of the principal, or even
of the secondary magnet. The power in the first induces a
corresponding power in the second, and that induces a motion
of the electricity in the wire round the latter, which electricity
produces the spark. It seemed to me, however, no difficult
matter to dispense with the secondary or temporary magnet,
and thus approach a step nearer to the original one; and this
was easily accomplished in the following manner. About 20
feet of silked copper wire were made into a short ring helix,
on one end of a pasteboard tube, through which a cylindrical
magnet, an inch in diameter, could move freely; one end of the
helix wire was fastened to a small amalgamated copper plate,
and the other end bent round so as to touch this plate perpen-
dicularly upon its flat surface, and also in such a manner that
when the magnet was passed through the cylinder it should
come against this wire, and separate the end from contact
with the plate. The consequence was that whenever this ac-
tion was quickly performed, the magneto-electric spark ap-
peared at the place of disjunction.

My apparatus was placed horizontally, and a short loos
plug of wood was put into the
end of the cylinder, so that the
disjunction at the plate should
take place at the moment the

end of the magnet was passing (Q_Jj|| — ) ->

through the helix ring, that be-
ing the most favourable condi-
tion of the apparatus. The mag-
net was driven with a sharp quick motion through the cylin-
der, its impetus being overcome, as soon as the spark was ob-
tained, by an obstacle placed at a proper distance on the out-
side of the moveable wire. From the brightness and appear-
ance of the spark, I have no doubt that if both ends of a
horse-shoe magnet were employed, and a jogging motion were
communicated to the light frame carrying the helices, a spark
equal, if not superior, to those which down to this time have
been obtained with magnets of a certain power, would be pro-
duced.

Thus the magneto-electric spark has been brought one step
nearer to the exciting magnet. The much more important
matter still remains to be effected of rendering that electricity
which is in the magnet itself, and gives it power, evident under
the form of the spark.

The next point to which I wish to direct your attention is

and on a peculiar Condition of Magneto-electric Induction, 351

the magneto-electric shock. This effect I have felt produced
by Mr. William Jenkins in a manner that was new to me ; and
as he does not intend to work out the result any further, but
has given me leave, through Mr. Newman, to make it known
to you, I think the sooner it is published the better. Mr.
Jenkins's apparatus consists of a helix cylinder formed of cop-
per wire in the usual manner. An iron rod, about 2 feet long
and half an inch in diameter, can be passed at pleasure into the
centre of this cylinder. The helix consists of three lengths of
wire, (which, however, might as well be replaced by one thick
wire,) the similar ends of which are soldered to two thicker
terminal wires, and on these are soldered also two short cop-
per cylinders, to be held in the hand and give extensive con-
tact. The electro-motor was a single pair of plates, exposing,
perhaps, 3 square feet of surface on both sides of the zinc
plate. On holding the two copper handles tightly in the
hands, previously moistened with brine, and then alternately
making and breaking the contact of the ends of the helix with
the electro-motor, there was a considerable electric shock felt in
the latter case, i. e. on breaking contact, provided the iron
rod were in the helix ; but none either on making or breaking
contact when the latter was away.

This effect appears very singular at first, in consequence of
its seeming to be the shock of the electricity of a single pair
of plates. But in reality it is not so. The shock is not due
to the electricity set in motion by the plates, but to a current
in the reverse direction, induced by the soft iron electro-
magnet at the moment when, from the cessation of the original
current, it loses its power. It is, however, very interesting
thus to observe an original current of electricity, having a very
low intensity, producing ultimately a counter current having
an intensity probably a hundredfold greater than its own, and
the experiment constitutes one of the very few modes we have
at command of converting quantity into intensity as respects
electricity in currents.

It has been generally supposed that the electric spark pro-
ducible by a single pair of plates can only be obtained upon
breaking contact; but this, as I have shown in the Eighth Series
of my Experimental Researches, is an error, and a very im-
portant one as regards the theory of voltaic electricity ; it is,
however, true that the spark upon breaking contact can be
very greatly exalted by circumstances having no such effect
upon that produced at the moment of making contact.

Every experimenter on electro-magnetism is aware, that
when the current from a single pair of plates is passed through
a helix surrounding a piece of soft iron (to produce an electro-

352 Mr. Faraday on the Magneto-electric Spark and Shock,

magnet,) the spark, upon breaking contact, is much brighter
than if the soft iron were away; and because this effect occurs
at the same moment with the shock in Mr. Jenkins's experi-
ment, it might at first be supposed that the electricity pro-
ducing both the spark and the shock was the same, and that
the effects of both were increased, because of the increase in
power of this their common cause. But the fact is not so, for
the electricity producing the spark is passing in one direction,
being that which the zinc plate and acid determine, whilst the
electricity producing the shock is circulating in the contrary
way.

From the appearance of the spark, which is always in this
form of the experiment due to the electricity which is passing
at the moment when contact is broken, it might seem that a
greater current of electricity is circulating during the time that
the contact is preserved, whilst the iron is present in the helix,
than when it is away. But this is not the case; for when the
quantity is measured by a very delicate galvanometer, it is
found to remain unchanged after the removal or replacement
of the iron, and to depend entirely upon the action at the zinc
plate. Still the appearance of the spark is an evident and
decisive proof, that the electricity which is passing at the mo-
ment of disjunction is of greater intensity when the iron is in
the helix than when it is away, and this increased effect is evi-
dently dependent, not upon any change in the state of things
at the source of the electricity, but in a change of the powers
of the conducting wire caused by the presence of the soft iron.
I do not suppose that this change is directly connected with
the magnetizing power of the current over the iron, but is due
rather to the power of the iron after it becomes a magnet, to
react upon the wire ; and I have no doubt, though I have
not had time to make the experiment, that a magnet of very
hard steel, of equal force with the soft iron magnet, if put into
the helix in the same direction, would exert an equal influence
over the wire.

I will now notice another circumstance, which has a similar
influence in increasing the intensity of the spark which occurs
when the junction of the circuit is broken. If a pair of zinc
and copper plates immersed in acid are connected by a short
wire, and all precautions are taken to avoid sources of inaccu-
racy, then, as I have already shown, the spark, upon breaking
contact, is not greater than that upon making contact. But
if the connecting wire be much lengthened, then the spark
upon breaking contact is much increased. Thus, a connecting
copper wire of y^th of an inch in diameter when 12 inches
long, produced but a small spark with the same pair of plates

and on a peculiar Condition of Magneto-electric Induction, 353

which the moment before or after would give a large spark
with a wire of the same diameter and 114 feet long. Again,
12 inches in length of wire ^th of an inch in diameter gave a
much smaller spark than 36 feet of the same wire.

In both these cases, though the long wires gave the larger
spark, yet it was the short wires which conducted the greatest
quantity of electricity in a given time ; and that was very evi-
dent in the one of small diameter, for the short length be-
came quite hot from the quantity of electricity passing through
it, whereas the larger wire remained cold. Still there can be
no doubt that the sparks from the long wires were of greater
intensity than those from the short wires, for they passed over
a greater interval of air ; and so the paradoxical result comes
forth, that currents of electricity having the same common
source, and passing the same quantity of electricity in the
same time, can produce in this way sparks of very different
intensity.

This effect, with regard to lengthened wires, might be ex-
plained by assuming a species of momentum as being acquired
by the electricity during its passage through the lengthened
conductor, and it was this idea of momentum which guided
Signori Nobili and Antinori in their process for obtaining
the magneto-electric spark by means of a common magnet.
Whether a current of electricity be considered as depending
upon the motion of a fluid of electricity or the passing of
mere vibrations, still the essentml idea of momentum might
with] propriety be retained. But it is evident that the similar
effect produced by the soft iron of increasing the intensity of
the spark cannot be explained in this way, i. e. by momentum ;
and as it does not seem likely that the effects, which in these
cases are identical, should have two causes, I believe that both
are produced in the same way, although the means employed
are apparently so different.

When the electric current passes through a wire, that wire
becomes magnetic; and although the direction of the mag-
netism is peculiar, and very different to that of the soft iron
placed in the helix of the first experiments, yet the direction
of the magnetic curves, both of the wire so magnetized and of
the soft iron magnet, in relation to the course which the cur-
rent is pursuing (i. e. in the conducting wire), is the same. If,
therefore, we refer the increased spark to a peculiar effect of
induction exerted by the magnetism over the passing electric
current, all becomes consistent. Let us, for instance, for the
sake of reference, represent the magnetism by the magnetic
curves : then, in die first place, the longer the wire the greater

Third Series. Vol.5. No. 29. Nov. 1834. 2 Z

354? Mr. Faraday on certain Magneto-electrical Phenomena.

the number of magnetic curves which can exert their induc-
tive influence ; and the effect in a wire of a hundred feet in
length will be nearly a hundred times greater than in a wire
of the same diameter only a foot in length. The reason why
a core of soft iron produces the same effect as elongation of
the wire, will be that it also brings magnetic curves into in-
ductive action exactly in the same direction as those around
the wire; and the rest of the circumstances, as far as I can per-
ceive, will accord with the cause assumed.

That the magnetic curves of the wire carrying the current
shall actually affect the character of the current which gives
them origin, need not excite any difficulty, for this branch of
science shows many such cases. Ampere's experiment of
revolving a magnet on its own axis, and the case which I have
shown of drawing away electricity from the poles and equa-
tor of a magnet when it is revolved, are both instances of the
same kind.

In conclusion, I wish to say that I think I see here some
of those indications of an electro-tonic or peculiar state of
which I have expressed expectations in the second series of
my Experimental Researches, par. 242.*; for though I here
speak of magnetism and magnetic curves for the sake of re-
ference, yet allowing Ampere's theory of the magnet, all the
effects may be viewed as effects of induction produced by elec-
trical currents. Hence many extensions of the experiments.
I have no doubt, for instance, that if a long wire were arranged
so as to discharge a single pair of plates, and the spark oc-
curring at the breaking of contact were noted, and then an-
other wire carrying a current in the same direction from
another electrometer, were placed parallel and close to but
without touching the first, the spark obtained on breaking the
contact at the first wire would be greater than before. This
experiment can easily be made with a double helix ; but at my
present distance from town I have no means of trying the
experiment, or of examining more closely these indications.

I am, my dear Sir, very truly yours,
Brighton, Oct. 17, 1834. M. FARADAY.

* Philosophical Transactions 1832, p. 189.

•\'

I

[ 355 ]

XL VI 1 1. On the Mummy Cloth of Egypt; with Observations
on some Maniifactures of the Ancients. By James Thomson,
Esq., F.R.S* .^ ^ _^ (rr<(yvJ, y )Ul

§ i. cu-d ^ f^i/L yttox^

T^HE inquiries which form the subject of the following
•*- paper were undertaken many years ago : circumstances
which it is unnecessary here to explain have delayed their
publication; but the results were communicated to numerous
individuals. The revival lately of similar inquiries by others
apparently unacquainted with what is already known, induces
me to believe that this communication may not be wholly
without interest.

My attention was attracted to the subject of Egyptian ma-
nufactures by the late Mr. Belzoni in the year 1822, during
the exhibition of a model of the ancient tomb discovered by
that enterprising traveller in Egypt. He had the goodness
to present to me various specimens of cloth, chiefly from the
mummies in his possession, one of which he had entirely de-
nuded.

On my remarking that these fabrics scarcely deserved the
appellation of " fine linen," which from all antiquity had been
bestowed on the linen of Egypt, and that the observations of
Dr. Hadley, in the Philosophical Transactions for the year
1 764, had thrown some doubt on the supposed fineness of this
linen, he informed me that during his researches in Egypt, in
those tombs and mummy-pits which he had explored, he had
met with cloth of every degree of fineness from the coarsest
sacking to the finest and most transparent muslin, a fact
which I subsequently found in a great degree confirmed by
the acquisition of some interesting specimens of mummy cloth
sent to this country by the then Consul-general of Egypt, the
late Mr. Salt. The subject appearing to me sufficiently in-
teresting to deserve investigation, and having collected a variety
of specimens of cloth, my first care was to ascertain of what
material they were made. This question had already engaged
the attention of various inquirers and given birth to learned
dissertations.

Rouelle, in the Memoirs of the French Academy of Sci-
ences for the year 1750 ; Larcher, the translator of Herodotus,
in the notes to that celebrated work ; and the learned John
Reinhold Forster, who wrote a tract De Bysso Antiquoncm,
had all endeavoured to prove from their own examination that

* Communicated by the Author.

2Z2

356 Mr. Thomson on the Mummy Cloth of Egypt ;

the mummy cloth of Egypt was cotton ; and this opinion, on
their authority, was adopted by the learned of Europe. It is
singular that neither in the memoir of Rouelle, nor in the
notes of Larcher, nor in the dissertation of Dr. Forster, in
which this opinion is expressed, are any grounds assigned
for, or any proofs given of, this opinion. The amount of
their assertion is, that having examined the bandages of va-
rious mummies, which are designated by them, and some of
which I have myself since carefully examined, they found all
those which were free from resinous matter to be cotton. I
am forced to confess that with all the attention I could be-
stow upon them, and with the assistance of various intelli-
gent manufacturers, I was unable to arrive at such a conclu-
sion. Some were of opinion that the cloth was cotton ; others
that it was linen ; and some, again, that there were in the col-
lection specimens of both, — a proof that our means of judging
were unworthy of confidence.

The great difference in the specific gravities as well as in
the conducting power of linen and cotton is sufficient to enable
us, by careful experiments, to discriminate accurately between
them ; and there are few individuals who have been accustomed
to the use of both cotton and linen who cannot readily di-
stinguish, by that delicate sense of touch diffused over the whole
body, between the two fabrics: but such tests require much
larger portions of the material than I had at my disposal,
many of the specimens submitted to my examination not be-
ing larger than a shilling. I found the difference of smell in
the burnt fibres, and the degree of polish which each kind
of cloth took on being rubbed with a glass stopper, as well as
other empirical modes suggested to me, liable to great uncer-
tainty, and I sought in vain for any chemical test. It occurred
to me that the supposed unfitness of cotton lint, compared
with linen, for dressing wounds, had been accounted for by
the different form of their fibres, the one being sharp and
angular, and the other round and smooth ; and, in fact, I found
in the 12th volume of the Philosophical Transactions, for the
year 1678, this structure ascribed to them by that early mi-
croscopic observer Mr. Leuwenhoek. It seemed to me, there-
fore, that the most simple mode of distinguishing between
cotton and linen would be to subject the fibres to examination
under a powerful microscope. Not being possessed of such
an instrument, nor accustomed to its management, my friend
Mr. Children undertook, through Sir Everard Home, to so-
licit the assistance of Mr. Bauer, whose labours are well known
to the scientific world, and whose microscopic drawings have
for a series of years enriched the Transactions of the Royal

with Observations on some Manufactures of the Ancients, 357

Society. I transmitted to him various fibres of cotton and
linen, both manufactured and in their raw state, as well as
fibres of unravelled mummy cloth, and in a few days I received
from him a letter, in which he pronounced every specimen of
mummy cloth subjected to his examination to be linen.

This letter was accompanied by a beautiful drawing, exhi-
biting the fibres of both raw and unravelled cotton as flat-
tened cylinders, twisted like a corkscrew, whilst the fibres
of linen and various mummy cloths were straight and cylin-
drical.

Repeated observations having established beyond all doubt
the power of the microscope accurately to distinguish between
the fibres of cotton and linen, I obtained, through the kindness
of various individuals connected with the British Museum, the
Royal College of Surgeons, the Hunterian Museum of Glasgow,
as well as other public institutions, both at home and abroad,
a great variety of cloths of human mummies, and of animals
and birds, which being subjected to the microscope of Mr.
Bauer, proved without exception to be linen ; nor has he,
amongst the numerous specimens we have both collected du-
ring many years, been able to detect a single fibre of cotton ;
a fact since recently confirmed by others, and proving incon-
testibly that the mummy cloth of Egypt was linen.

§ii.

The filaments of cotton when viewed through a powerful
instrument, such as the improved achromatic microscope of
Ploessl of Vienna, which for magnifying power and clear-
ness of vision Mr. Bauer has found superior to every other
he has had an opportunity of using, appear to be trans-
parent glassy tubes, flattened, and twisted round their own
axis. A section of the filament resembles in some degree a
figure of 8, the tube originally cylindrical having collapsed
most in the middle, forming semi-tubes on each side, which
give to the fibre, when viewed in certain lights, the appearance
of a flat ribbon with a hem or border at each edge. The
uniform transparency of the filament is impaired by small ir-
regular figures, in all probability wrinkles or creases arising
from the desiccation of the tube. The twisted and corkscrew
form of the filament of cotton distinguishes it from all other
vegetable fibres, and is characteristic of the fully ripe and ma-
ture pod, Mr. Bauer having ascertained that the fibres of the
unripe seed are simple untwisted cylindrical tubes, which
never twist afterwards if separated from the plant; but when
the seeds ripen, even before the capsule bursts, the cylindrical
tubes collapse in the middle and assume the form already de-

358 Mr. Thomson on the Mummy Cloth of Egypt;

scribed, and which is accurately delineated in the accompany-
ing drawing.

This form and character the fibres retain ever after, and in
that respect undergo no change through the operation of
spinning, weaving, bleaching, printing, and dyeing, nor in all
the subsequent domestic operations of washing, &c, till the stuff
is worn to rags; and then even the violent process of reducing
those rags to pulp for the purpose of making paper, effects
no change in the structure of these fibres. " With Ploessl's
microscope," says Mr.Bauer, " I can ascertain whether cotton
rags have been mixed with linen in any manufactured paper
whatever."

The elementary fibres of flax {Linum usitatissimum) are also
transparent tubes, cylindrical, and articulated or jointed like a
cane. This latter structure is only observable by the aid of
an excellent instrument. They are accurately delineated in
the annexed engraving.

Explanation of the Plate.

First row of figures: A. Fibres of the unripe seed of cotton.
In that state the fibres are perfect cylindrical tubes. At* is
a fibre represented as seen under water, showing that the water
had gradually entered and inclosed several air-bubbles, prov-
ing the tube to be quite hollow and without joints.

B. The first two fibres are from ripe cotton and are already
twisted, though the pod or capsule is not yet burst, and is
still on the growing plant. The other three fibres are of raw
cotton prepared for manufacture.

C. Various fibres of unravelled threads of manufactured
cotton. The fibres of cotton in the annexed drawing are re-
presented T^ of an inch in length, and are magnified 400
times in diameter. In thickness these fibres vary from ^^
to t^q o Part °f an incn* The twists or turns in a fibre of
cotton are from 300 to 800 in an inch.

Second row of figures :

Fig. 1. Fibres of raw flax before spinning.

Fig. 2. Fibres of unravelled threads of manufactured flax.

Figg. 3, 4?, 5. Fibres of the unravelled threads of various

mummy cloths.
Fig. 6. Fibres of unravelled threads of the cloth of Dr.

Granville's mummy, supposed to be cotton. The

specimens are all flax, and the fibres remarkably

strong and large.
Fig. 7. Fibres of unravelled threads of several Ibis mummies.
Fig. 8. Fibres of unravelled threads of the mummy of an

ox's head.

with Observations on some Manufactures of the Ancients, 359

All the annexed figures of fibres of flax represent each y^
of an inch in length, and are magnified 400 times in diameter.
They vary in thickness from -^^ to 7#W Part °* an hich.

§ III.

Of the productions of the loom amongst the nations of
antiquity, with the exception of those which form the sub-
ject of this paper, we know only what is to be gathered from
the few scattered notices in ancient writers. Even the great
work of Pliny, the encyclopaedia of that day, and with all its
defects an invaluable collection of facts, affords but scanty in-
formation. Of the manufactures of the Egyptians and of their
domestic arts our knowledge is more ample, but we are more
indebted to their monuments than to their historians'; and the
paintings which adorn their tombs, and which are fresh at the
present day as from the hand of the artist, have revealed to us
more than all the writers of antiquity.

Of the products of the Egyptian loom, however, we know
scarcely more than the mummy-pits have disclosed to us ; and
it would be as unreasonable to look through modern sepul-
chres for specimens and proofs of the state of manufacturing
art amongst ourselves, as to deduce an opinion of the skill of
the Egyptians from those fragments of cloth which envelop
their dead, and have come down, almost unchanged, to our
own time. The curious or costly fabrics which adorned the
living, and were the pride of the industry and skill of Thebes,
have perished ages ago. There are, however, amongst these
remains some which are not unworthy of notice, which carry
us back into the workshops of former times, and exhibit to
us the actual labours of the weavers and dyers of Egypt more
than two thousand years ago.

The great mass of the mummy cloth employed in bandages
and coverings, whether of birds, animals, or of the human
species, is of coarse texture, especially that more immediately
in contact with the body, and which is generally impregnated
with resinous or bituminous matter. The upper bandages,
nearer the surface, are finer. Sometimes the whole is en-
veloped in a covering coarse and thick, and very like the
sacking of the present day ; sometimes in cloth coarse and
open, like that used in our cheese-presses, for which it might
easily be mistaken. In the College of Surgeons are various
specimens of these cloths, some of which are very curious.

The beauty of the texture and peculiarity in the structure
of a mummy cloth given to me by Mr. Belzoni was very
striking. It was free from gum, or resin, or impregnation of
any kind, and had evidently been originally white. It was

360 Mr. Thomson on the Mummy Cloth of Egypt;

close and firm, yet very elastic. The yarn of both warp and
woof was remarkably even and well spun. The thread of the
warp was doable, consisting of two finer threads twisted toge-
ther. The woof was single. The warp contained 90 threads
in an inch ; the woof, or weft, only 44. The fineness of these
materials, estimated after the manner of cotton yarn, was about
30 hanks in the pound.

The subsequent examination of a great variety of mummy
cloths showed that the disparity between the warp and woof
belonged to the system of manufacture, and that the warp
generally had twice or thrice, and not seldom four times, the
number of threads in an inch that the woof had : thus, a cloth
containing 80 threads of warp in the inch, of a fineness about
24 hanks in the pound, had 40 threads in the woof; another
with 120 threads of warp of 30 hanks had 40; and a third
specimen only 30 threads in the woof. These have each re-
spectively double, treble, and quadruple the number of threads
in the warp that they have in the woof. This structure, so
different from modern cloth, which has the proportions nearly
equal, originated, probably, in the difficulty and tediousness of
getting in the woof when the shuttle was thrown by hand,
which is the practice in India at the present day, and which
there are weavers still living, old enough to remember the
universal practice in this country.

I have alluded to some specimens of mummy cloth sent to
this country by the late Mr. Salt. I am unacquainted with
their history or origin further than that they were brought
from Thebes, and were contained in the outer packing-case
of a mummy now in the British Museum. They were evi-
dently the spoils of some other mummy, but when and where
opened I have in vain endeavoured to learn. There were va-
rious fragments of different degrees of fineness ; some fringed
at the ends, and some striped at the edges. They merit a
more particular description.

My first impression on seeing these cloths was that the
finest kinds were m?islin, and of Indian manufacture, since we
learn from the " Periplus of the Erythrean Sea," ascribed to
Arrian, but more probably the work of some Greek mer-
chant himself engaged in the trade, that muslins from the
Ganges were an article of export from India to the Arabian
Gulf; but this suspicion of their being cotton was soon removed
by the microscope of Mr. Bauer, which showed that they were
all without exception linen. Some were thin and transparent,
and of very delicate texture. The finest appeared to be made
of yarns of near 100 hanks in the pound, with 140 threads in
the inch in the warp, and about 64 in the woof. A specimen

ivith Observations on some Manufactures of the Ancients. 361

of muslin in the Museum of the East India House, the finest
production of the Dacca loom, has only 100 threads in an inch
in the warp, and 84 in the woof, but the surprising fineness of
the yarns, which, though spun by hand, is not less than 250
hanks in the pound, gives to this fabric its unrivalled tenuity
and lightness.

Some of the cloths were fringed at the ends, and one, a sort
of scarf about four feet long and twenty inches wide, was
fringed at both ends. Three or four threads twisted together
with the fingers to form a strong one, and two of these again
twisted together and knotted at the middle and at the end to
prevent unravelling, formed the fringe, precisely like the silk
shawls of the present day.

The selvedges of the Egyptian cloths generally are formed
with the greatest care, and are well calculated by their strength
to protect the cloth from accident. Fillets of strong cloth or
tape also secure the ends of the pieces from injury, showing a
knowledge of all the little resources of modern manufacture.
Several of the specimens, both of fine and coarse cloth, wrere
bordered with blue stripes of various patterns, and in some
alternating with narrow lines of another colour. The width
of the patterns varied from half an inch to an inch and a
quarter. In the latter were seven blue stripes, the broadest
about half an inch wide nearest the selvedge, followed by five
very narrow ones, and terminated by one an eighth of an inch
broad. Had this pattern, instead of being confined to the
edge of the cloth, been repeated across its whole breadth, it
would have formed a modern gingham, which we can scarcely
doubt was one of the articles of Egyptian industry. A small
pattern about half an inch broad formed the edging of one of
the finest of these cloths, and was composed of a stripe of blue
followed by three narrow, lines of the same colour, alternating
with three lines of a fawn colour, forming a simple and ele-
gant border. These stripes were produced in the loom by
coloured threads previously dyed in the yarn. The nature of
the fawn colour I was unable to determine. It was too much
degraded by age, and the quantity too small to enable me to
arrive at any satisfactory conclusion. Though I had no doubt
the colouring matter of the blue stripes was indigo, I sub-
jected the cloth to the following examination. Boiled in water
for some time, the colour did not yield in the least ; nor was
it at all affected by soap, nor by strong alkalies. Sulphuric
acid, diluted only so far as not to destroy the cloth, had no ac-
tion on the colour. Chloride of lime gradually reduced, and
at last destroyed it. Strong nitric acid dropped upon the
blue turned it orange, and in the same instant destroyed it.
Third Series. Vol. 5. No. 29. Nov. 1834. 3 A

362 Mr. Thomson on the Mummy Cloth of Egypt ;

These tests prove the colouring matter of these stripes to be
indigo.

This dye was unknown to Herodotus, for he makes no
mention of it. It was known to Pliny, who, though ignorant
of its true nature and the history of its production, has cor-
rectly described the most characteristic of its properties, the
emission of a beautiful purple vapour when exposed to heat.
Had his commentators been acquainted with the sublimation
of indigo, it would have saved many learned doubts. We
learn from the " Periplus," that it was an article of export
from Barbarike on the Indus to Egypt, where its employment
by the manufacturers of that country, probably from a remote
period, is clearly established by the specimens here described.

Amongst the various cloths for which I am indebted to the
curators of the Hunterian Museum at Glasgow, is one of a
pale brick or red colour. My attention was lately recalled to
this specimen by observing a similar colour in the outer co-
verings of two fine mummies presented to the University of
London by Mr. Morrison, one of which has been recently
unrolled. Having obtained specimens of both, I subjected
them, with that from Glasgow, to the following experiments.
Treated with cold water the colour was not affected. Boiling
distilled water in a few minutes nearly removed the whole.
Diluted sulphuric or muriatic acid had no action on it; but
a feeble alkali, whether carbonated or caustic, destroyed the
colour immediately. Examined with a lens, the specimens
from Glasgow exhibited small distinct grains or concretions,
of a red colour, disseminated through the fibres of the cloth.
Notwithstanding the fugitive nature of the colouring matter
of Safflower, the Carthamus tinctorius of botanists, I am
strongly disposed to consider the three specimens here ex-
amined as having been dyed with that plant. The small
granular particles of a red colour observed in the Glasgow
specimen are sometimes found in cloth dyed with Carthamus.
There is also in the covering of the mummy of the London
University which is unstripped, a rosy hue peculiar to this
dye. The resistance of the colour to acids and its instant

iielding to the weakest alkalies is characteristic of Safflower.
,astly, Carthamus has long been an article of cultivation in
Egypt, and the first processes employed by the European
dyers were derived, with the dye itself, from that country,
where in all probability it has been cultivated and used for
ages, and is to this day an article of considerable export.

In the Glasgow mummy there was, moreover, a narrow
slip of cloth about four inches broad, extending from the
crown of the head to the feet, of a yellowish colour, of which

with Observations on some Manufactures of the Ancients. 363

portions were still fresh. On examination no mordant ap-
peared to have been used to fix this dye, and washing in cold
water greatly impaired it. Comparative experiments made on
this colour, and on that afforded by Carthamus to simple
water before the pink dye is extracted, left little doubt of their
being identical. They were slightly and similarly affected by
solutions of alumina and of iron, and appeared to have very
feeble affinities for either vegetable fibre or any of the earthy
or metallic bases.

Though the age of the mummies from which these speci-
mens were derived has not been ascertained, yet we may fairly
presume that it goes back to a period so far remote as to make
the preservation so long, of delicate and fugacious colouring
matter like Carthamus, or even the more permanent one of
indigo, very surprising, and proves that substances which readily
yield to the combined and destructive agency of heat or light
and moisture, are almost unalterable when secured from the
action of the latter. Portions of the blue cloth which had re-
sisted in the dark and dry sepulchres of Thebes for ages,
lost, by a few days' exposure on the grass, nearly all their
colour.

Mummy cloth not stained or discoloured by resin or bitu-
men is generally of a pale-brown or fawn colour, which has
been supposed to arise from some astringent preparation
employed by the Egyptians for its preservation. All this
cloth imparts to water a brown colour, in which I have sought
in vain for any trace of tannin. In none of the specimens
I have examined did either gelatine or albumen, or solu-
tions of iron, afford any precipitate; but the subacetate of
lead produced a cloud, indicating the presence of extractive
matter. I am inclined to think that if astringent matter has
been found, it is in those bandages which have received a pre-
paration of gum or resin, and which are distinguished from
the others by their stiffness. These I have not examined.
All these cloths, whether fine or coarse, are more or less
rotten. Of the numerous specimens which have fallen under
my notice, the outer covering of the fine mummy in the Lon-
don University has suffered least : it is comparatively sound.
Whether this be an argument against its high antiquity, I
know not; but the cloth is evidently ancient Egyptian : nor is
it, I believe, pretended that in those factitious mummies ma-
nufactured by the Arabs, of which several were found by
Blumenbach in the British Museum, the bandages and en-
velopes are not genuine. Of the ancient cloth there is such
an accumulation in the mummy pits and sepulchres of Egypt,
as to have become an object of speculation in Europe, for the

3 A 2

364- Mr. Thomson on the Mummy Cloth of Egypt,

purpose of making paper. The inquiries, therefore, which
form the subject of this communication are not affected by any
question of the integrity of those mummies from whence the
specimens were derived, of which, however, no doubt is enter-
tained.

The period during which the custom of embalming pre-
vailed in Egypt, embraces a long succession of ages. From
the first of thePharaohs to the last of the Ptolemies, with whom
this ancient rite is supposed to have become almost extinct,
chronologists reckon more than twenty centuries during
which the art was practised which has handed down to us
these scanty remains of Egyptian industry, the only vestiges
of the labours of the ancient loom now in existence. They
prove the arts of spinning and weaving flax to have attained
a high degree of perfection, many of the specimens of mummy
cloth here described being of a quality to excite admiration
even at the present day, and the finest of these fabrics ap-
proaching in excellence our delicate muslins. The coloured
borders establish the fact of indigo having been known and
used as a dye in Egypt, from a remote aera.

During this long period, industry and the arts of life con-
nected with civilization must have made considerable pro-
gress, which we shall, however, remain unable satisfactorily
to trace till more accurate knowledge of the ancient language
and characters of the Egyptians shall have interpreted the
dates, and fixed the chronology of their monuments and
paintings. In the tomb of Beni Hassan is a representation
of a loom (figured in Count Minutoli's Travels) of such pri-
maeval simplicity as to resemble the first rude efforts of savage
art to form a web, such as Don Ulloa in his voyages has de-
scribed as used by the native Indians of South America.
Between this loom, and that in which the corslet of Amasis
was woven, mentioned by Herodotus, and more particularly
described by Pliny as a wonderful specimen of manufacturing
art, the distance is immense.

It is not improbable that future researches directed to this
object may discover, in the ancient sepulchres and mummy
pits, fragments of cloth, now trodden under foot and unheeded
by the traveller, which would throw much light on the inter-
esting subject of ancient manufactures.

The question debated amongst the learned of the nature of
the Byssus of the ancients, I may in conclusion be permitted
to observe, appears to me to be finally settled by the present
communication. Herodotus states that the Egyptians wrapped
their dead in cloth of the Byssus. It has been shown that
without exception every specimen of mummy cloth yet ex-

Mr. Blackburn on the Modern Telegraphs. 365

amined has proved to be linen. We owe, therefore, the satis-
factory establishment of the fact, that the Byssus of the an-
cients was flax, to the microscope of Mr. Bauer.

XLIX. A Method of determining the Number of Signals
which can be made by the Modern Telegraphs* By Charles
Blackburn, Esq., B.A.

To the Editors of the Philosophical Magazine and Journal.

Gentlemen,

TN the Number of the Philosophical Magazine for Octo-
■*■ ber, you did me the favour to insert a method of find-
ing the number of signals which can be made by sema-
phores having one arm on a centre; I now send an investi-
gation for finding the signals when the semaphores have any
given number of arms on the same centre.

Problem. — To find the number of signals which can be
made by a semaphore having any number
of centres; any given number of arms on
each centre; and each arm taking any
given number of positions.

Let the figure represent a semaphore
having any number of centres, A, B, &c,
and any number of arms, AD, AE, &c,
on the same centre ; let also the number
of centres be denoted by c, the number
of arms by a, and the number of the po-
sitions of each arm as p.

First, to find the number of signals
which can be made by using the arms on
one centre only.

The number of positions in which each
arm can be placed may be considered as
distinct quantities capable of a certain
number of combinations. The number
of positions of each arm beings, the num-
ber of signals which can be made with
one arm only must = p.

And since the number of combinations of p things, taken

two and two together, is \ ~Z , the number of signals, using

1 • 38

two arms only, will be

1.2 '

In like manner the number,

366 Mr. Blackburn on the Modem Telegraphs,

T) T) — 1 T) ■" ■" 2

when three arms are made use of, will be -:— — — '— ; and

when all the arms on the centre are used, the signals will be

\ l£. *" s£ — - . Hence the total number of signals

1 .2 a-1 .a

which can be made by the arms on a single centre will be re-
presented by the sum of the series

^+-172" 1.2.3 +'&C 1.2 T=l.«~

to a terms.

Let the sum of this series be denoted by A ; then since the
number of centres = c, the whole number of signals which can
be made, using the arms on a single centre at a time, =cA.

Again, since the signals which can be made on any one
centre can be combined with each of the signals on any other
centre, it follows that the number which can be made, using
any two centres at a time, = A2.

Also, since the signals which can be made upon any two
centres may be combined with each of the signals upon any
other centre, it follows that the number of signals, using any
three centres at once, will be A3.

In like manner it may be shown that the signals, using c
centres at once, will be Ac. Hence

The number of signals using one centre at a time as A

— two centres = A2

&c. &c. &c.

c centres = Ac

Again, since the number of combinations of c things, taken

c . c 1

two and two together, = ~- — — -, it follows that the number of

different pairs of centres which can be taken together will be

* ~ ; and since the number of signals with each pair of

centres = A2, the total number of signals which can be made,

c • c —~ 1
using a pair of centres at once, will be —J — — - . A2.

1.2

Also, since the number of combinations of c things, taken
three and three together, is — '— — ^—- — , the number of dif-

Mr. Blackburn on the Modern Telegraphs, 367
ferent sets of three centres will be C-^fl^l; and since the

number of signals which can be made upon any three centres
is A3, it follows that the total number of signals, when three

centres are used at once, will be c'c~l *J^g as &c

1.2.3 '

In like manner, the numbers, when c centres are used at

once, will be C*"-ri "' *l£=i fe^Ej} a*

1.2 *~l).c

It appears, then, that the whole number of signals which can
be made by the instrument, will be represented by the sum of
the series

cA + c-^=La»+,&c c.<T=T ... {c-TZTi} Ac

1 * A 1.2 c

to c terms, in which expression A = p+P'P~~ ■ -f, &c. to a
terms. But by the binomial theorem, the sum of the series,

cA+c4^1 A*+&c. c- MB "{'-^1 A.

1 • ^ 1.2 c

I - (A+l)«-l;
hence the number of signals will be represented by the for-
mula (A + l)c— 1.

Example. — Let it be required to find the number of signals
which can be made by the Admiralty semaphore.

In this example a = 1, c = 2, /> = 6; and since a = 1,
A =x a, and the expression (A + l)c— 1 becomes (6+ I)2— 1
= 48, the number required.

Example 2. — To find the number of signals which could
be made by the Admiralty semaphore supposing it to have
two arms upon a centre.

Here a = 2, .*. A = p • —q— = ~k~ » nence tne signals
willbe(15+l)9-l = 255.

Corollary. — The number of signals which can be made,
using any one centre, will be represented by the second term
of the binomial A + 1 raised to the cth power ; the number
using two centres, by the third term of the same power; and
so on. Thus,

368 Mr. Blackburn on the Modern Telegraphs.

The signals using one centre at a time = cA

using two centres

c . c— 1

using three centres = — - — - — - — . Ai\

&c. &c. &c.

using c centres =

Corollary 2.— In any semaphore which has as many arms
upon each centre as each arm has positions, the formula for
the number of signals will be 2ac— 1.

For in this case, since

1 .2

m

c

.c —

1 .

l.c-2
2 . 3

c

. c-

^T

• • •

{c

-.-1}

1

. 2

c

a. a — I a. a — 1 . a— 2 - Q

a ~p, A = a + 1<2 + j . 2 . 3 + > &c*' to a

terms = 2a — 1. Hence by substituting for A in the formula
(A+l)c— 1 we have(2°)c— 1 = 2oc — 1.

Example.— Let «=p = 6, c=2; then 2ac — l = 212— 1
= 4095, which is the number of signals which could be pro-
duced by the Admiralty semaphore, if it had six arms upon
each centre instead of one.

Example 2. — To find the number of signals which might be
made with a pocket watch, supposing twelve instead of two
fingers on the same centre.

Here a = 12, c = 1, therefore 2ac- 1 = 212-1 = 4095,
as in the preceding example.

All the signals requisite for the purposes of communication
may be exhibited by machines of great simplicity. A tele-
graph like that in the an-

Nkl ±kL

nexed sketch is capable of
producing sixteen thousand — ^~-
three hundred and eighty-
three distinct signals; and
since these admit of a sy-
stematic arrangement, by which the signal for every word,
and the word to every signal, may immediately be found, it
seems desirable that lines of telegraphs should be established
between the metropolis and the more important towns. Com-
munications of any nature might then be conveyed verbatim
with the utmost facility, and with a rapidity approaching even
to the velocity of light.

[ 369 ]

L. Observations on the Growth and on the bilateral Symmetry
of Echinodermata. By L. Agassi z, M.D. and Professor
of Natural History at NeuchateL*
rT,HE most general character which has been usually as-
-*■ signed to the Echinodermata, is to have all the parts of
their body similar to one another, and disposed like rays
around a common centre : it is a character in which this class
has been supposed to partake with the entire division of ra-
diated animals. Nevertheless, on a close examination of this
radiated structure, we find that these rays are always dissimi-
lar, but in different degrees in different genera; and that they
are not always connected with a centre of the same nature. If
we trace the arrangement of parts in the Spatangi, for instance,
we are soon led to see that the more or less elongated form
of their body is caused by the position of the mouth and the
anus, which are placed near the two extremities of the body ;
and that four of the ambulacral series, and also four of the
interambulacral series, are pairs, and symmetrically placed on
the two sides of a plane, which, if extended from the mouth to
the anus, would divide the animal into two equal parts. The
5th ambulacral series, and also the 5th interambulacral series,
are single, and not symmetrical. The ambulacral series which
passes above the mouth (and which is odd, or not paired,) is
consequently the anterior series ; whilst the posterior part of
the body is occupied by an interambulacral series : it is in the
central line between its plates that the anus is placed. We
have then in the Spatangi an anterior region, distinguish-
able by the unequal ambulacral series, and a posterior region,
distinguishable by the unequal interambulacral series. On
the two sides of the animal the series of plates are disposed in
symmetrical pairs, in such a manner that there are two pairs
of ambulacral series and two of interambulacral on the right,
and two on the left. The first anterior pair, which adjoins
the unequal ambulacral series, is a pair of interambulacral
series, immediately behind which is placed the first pair of
ambulacral series, then a second pair of interambulacral, and
lastly, a second pair of ambulacral series. Behind these is
the uneven posterior interambulacral series.

As to the Clypeasters, the Galerites, the Nucleolites, &c, in
which the mouth is central and the anus marginal or sub-
marginal, it is nevertheless easy to understand the position of
the bilateral parts, because the position of the posterior inter-
ambulacral series being given by the position of the anus,

* Communicated by the Author.
Third Series. Vol. 5. No. 29. Nov. 1834. 3 B

370 Dr. Agassiz's Observations on the Growth and on

there is no difficulty in understanding the symmetrical rela-
tions of the other even and odd series. We can always re-
cognise differences in the form of the component plates, and
of the ambulacra of the different pairs, which show evidently
the appearance of bilateral parity. These, however, are less
apparent in the Clypeasters than in the Spatangi. Hence
these data become important for the study of the internal soft
parts and for the appreciation of their functions.

It might seem that in passing to the Echini and Asterice
(simple or ramified), whose mouth is perfectly central, and
whose anus, when there is one, is likewise found in the middle,
but upper part of the body, there would be no further traces
of this bilateral symmetry, and yet even here it is easy to de-
termine the relations of all the radiated parts and of the longi-
tudinal anterioposterior axis. All the radii of these animals
resemble one another so much outwardly, that we might
hardly expect to find in their arrangement traces of the bila-
teral symmetry which is so evident in the Spatangi, &c. But
if we take into account the differences which exist in the
structure of the plates of different series, we shall be convinced
that here also the symmetry in pairs is maintained under the
appearance of a disposition completely radiated ; in fact, we
find in the upper part of the disk of the Echinodermata, espe-
cially in the Echini, the Cidarites, &c, in the region where
the ambulacral and interambulacral series converge, five
perforated plates of peculiar form, which have been called
oviducal plates, and are connected with the ovaries, and five
interoviducal plates connected with the aquiferous system.
The five largest of these plates (the oviducal ones) alternate
with the extremities of the ambulacral series; four of these
are, therefore, even, and one is odd. That which is odd has
a porous particular structure; it is the mad reporiform body
of the Asterice, which equally exists in the Echini, but under
another form : it is always in the posterior region of the body,
and when it becomes imperceptible, the space where a lacuna
is observed still points out the posterior region of the body,
as the mad reporiform body of the Asterice shows that the ray
opposite to it is the odd anterior ray, whilst the four others
are even, and placed on the right and left sides of the animal.
The same is the case with the Solasteria?, with this difference
only, that in them the number of the pairs is more consider-
able, and that sometimes there is no uneven ray.

In order rightly to comprehend the mode of growth of the
Echinodermata, it is necessary to keep in view the general
disposition of the solid pieces that constitute their covering:
they are plates of greater or less size, disposed in vertical

the bilateral Symmetry of Echinodermata. 3 7 1

zones, diverging from the mouth to the periphery of the body,
and converging from thence to the upper centre of the animal.
The mouth obviously points out to us the anterior part of the
body ; but its ordinary position makes it look as if placed in
the inferior part of the animal, but in no other respect changes
the relations of the parts of the body to one another. We
distinguish three principal types in the forms of these ani-
mals; some are tubular (the Holothurice), others spheroidal
(the Echinoides), and others star-shaped (the Asterides) ; but
they may be reduced to two types, as the tubular form may
be viewed in this case as an elongated spheroid : still further,
these two types may be reduced to one and the same plan of
organization, since the enlargement or multiplication of the
ovarial plates at the summits of such a spheroid, and of the
plates around the mouth, accompanied by a contraction of the
interambulacral plates, would produce a star, whilst, vice versa,
the enlargement of the extreme interambulacral plates, and
the contraction of the central plates of a star, would produce
a spheroid. This is not a mere supposition; the essential
difference between the Echini and the Asterice consists in this
different mode of increase of parts which are essentially the
same. As to the general disposition of the plates in Echino-
dermata, there are generally twenty series of them, forming
ten zones, of which one half are pierced with holes, whilst the
other half are entire. The five zones or double series of per-
forated plates are called the ambulacral series; the others are
the interambulacral series. In the Starfish (Asteria?) the large
plates of the sides of two adjacent radii answer to an inter-
ambulacral series of the Echini, whilst each radius has a com-
plete ambulacral series extending from the mouth to the ex-
tremity of the radius, and thence back to the upper centre.
The middle part of each ambulacral series, or the extreme
point of each radius, is consequently the narrowest, and its
two ends, or the basis of each radius, the widest. Each radius
is, in fact, composed of two parts, resembling two isosceles
triangles united by their summits and laid one over another ;
whereas in the Echini the centre of each series is the widest,
and the extremities are the narrowest, like two triangles united
by their bases at the equator of the sphere.

With respect to the original relations of all the plates which
form these series, we should entertain a false idea if we re-
presented them to ourselves as growing really in that vertical
succession which they seem to possess. It is, indeed, at the
summits of the series that the new plates are formed, but they
succeed each other, like leaves in plants/spirally, from one in-

3 B 2

372 Dr. Agassiz's Observations on Echinodermata.

terambulacral series to another, so that those which lie in a
vertical line one upon another, do not succeed each other in
the order of their first growth.

The growth of the plates of Echini takes place chiefly at
the upper summit of the shell, and the plates enlarge from the
top towards the bottom until they arrive at the greatest cir-
cumference of the spheroid, where they become entirely con-
solidated: at the lower summit, i.e. around the mouth, the
growth only takes place during the youth of the animal.
Hence arise the differences of form which are observable be-
tween the young and the old Echini. In youth they are com-
paratively flat, and become more and more conical as they
advance in age. In the Starfish the new plates are found in
the angles of the radii nearest to the upper surface and lower
surface of the body ; and increasing more and more, they keep
carrying to a greater distance the extremity of the radii. Thus,
then, the number of the plates is continually increasing, and
cannot be employed as a specific character. Hence we see
how an Echinus or a Starfish receives its increase, still pre-
serving its essential form and the relative disposition of its
parts.

The same system prevails in the structure of the Crinoidea.
In their internal organization it is well known that these animals
had between their five rays a depression, which no doubt con-
tained their soft organs; but the nature of this cavity is in
part unknown, because the interposition of the rays usually
obscures the view of their central region ; yet after a close
examination of many specimens of Br i avian Pentacrinite, I
have found that the branching rays are disposed around an
inclosed cavity, having walls composed of plates distinct from
those of the rays. The summit of this pouch presents an
aperture surrounded with certain plates stronger than the
rest. This aperture is the mouth, with its manducal plates.
in many of the Crinoidea, particularly in the Actinocrinites,
I have observed on the side of this cavity a second large
aperture, placed between two rays of the animal. I consider
this to be the anus ; if so, this aperture occupies the same
place as in the P. europceus, and presents a new resemblance
to it. These data are sufficient to determine the bilateral dis-
position of the parts in the Crinoidea, as in the Echini and
Astoria, and to point out which of the rays are pairs, and
which is the odd ray. The differences which exist between
them are so great, that in certain genera, e. g. in the Pentre-
mites and Actinocrinites, they are obvious at the first glance.

As for the genera established in the whole class, I have

Mr. Addams on a peculiar Optical Phenomenon. 373

found that the characters drawn from the combination of the
plates, and from the disposition of the ambulacra, form divi-
sions more natural and better defined than the characters
taken from the position of the mouth and of the anus.

I shall publish my detailed observations upon this subject
in a monograph of the Echi?iodermata9 accompanied with plates,
for which I have already collected the greater part of the ne-
cessary materials.

LI. An Account of a peculiar Optical Phcenomenon seen after
having looked at a moving Body, Sfc. By R. Addams, Lee-
turer on Chemistry and Natural Philosophy*.

PJURING a recent tour through the Highlands of Scot-
-*-^ land, I visited the celebrated Falls of Foyers on the
border of Loch Ness, and there noticed the following phe-
nomenon.

Having steadfastly looked for a few seconds at a particular
part of the cascade, admiring the confluence and decussation
of the currents forming the liquid drapery of waters, and then
suddenly directed my eyes to the left, to observe the vertical
face of the sombre age-worn rocks immediately contiguous to
the water-fall, I saw the rocky surface as if in motion upwards,
and with an apparent velocity equal to that of the descending
water, which the moment before had prepared my eyes to
behold this singular deception.

The cascade is through a depth of about 70 feet, and my
position, as I stood when I made the observation, was nearly
on a level with the centre of the fall, being the lowest of the
two situations where visitors obtain a view of this copious and
never-failing infusion of peatf gushing over the giant step
and whitening as it flows. My attention was engaged on that
part of the fall which corresponded with a horizontal plane
passing through my eye and the water. The sun was masked
by cloud at the time.

I am not aware of any existing explanation of this class of
optical phenomena, and I may be premature in venturing the
following.

I conceive the effect to be owing to an involuntary and un-
conscious muscular movement of the eyeball, and thus occa-
sioning a displacement of the images on the retina.

Supposing the eyes to be intently gazing at any point in a

• Communicated by the Author.

f The colour is brown from flowing over peat moors.

374? Mr. Addams on a peculiar Optical Phenomenon.

transverse plane passing through a vertically moving body,
they will naturally and even irresistibly tend to follow the
motion of that body; nor can the muscular apparatus of the
eye maintain a stable equilibrium when the sight is fatigued
and bewildered with a rapid change of moving forms before
the eye.

Now in the case of the descending water, the eyes, being
directed to a particular part in a horizontal section of it, can-
not be prevented moving downwards through a small space :
every new form in the moving scene invites the eyes to ob-
serve, and for that reason to follow it; but the voluntary
powers are engaged to raise the axes of the eyes again to the
section. This depression of the axes below the intentional
point of sight seems to be repeated three or four times per
second, whilst looking at the water-fall. Then, when the eyes
are suddenly turned upon the rock, the muscles, having been
brought into a kind of periodic contraction, will perform at
least one of these movements after the exciting cause ceases
to act; and thus the axes of the eyes, by moving downwards,
will occasion a motion of the image of the rock over the re-
tina in a direction from above downwards, and consequently
the object giving that image will appear to move the con-
trary way, that is, upwards, agreeably to observation.

The deception, so far as I could judge, seemed to continue
for a time equal to the interval of a periodic motion of the
eye downwards when looking at the water, and, as before
stated, one third or one fourth of a second.

The same kind of phenomenon may be produced by mov-
ing the eye before fixed bodies, and also when the motions
are executed horizontally.

I have since been enabled to observe the appearance, with
certain peculiar variations, whilst travelling parallel to one
side of a narrow valley or lake, and looking across to the
other. It takes place when moving in ships in sight of proxi-
mate land.

It is also producible by mechanical means, such as by a rapid
unrolling of pieces of calico having some pattern or markings
on them ; and likewise by moving the head up and down, or
laterally: but to particularize all the circumstances would
make this communication inconveniently long.

[ 375 ]

LI I. An Account of some curious Facts respecting Vision.

By K.

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

[ THINK the following facts, which, I believe, have not been
■■■ before observed, may be sufficiently interesting to find a
place in your Journal.

About six months since I suffered much from nervous head-
aches, which terminated in amaurosis of the left eye.

For some time after the commencement of the disease, I
could perceive with the diseased eye, though with some diffi-
culty, the letters forming the body of the Philosophical Ma-
gazine.

Most of your readersare probably aware that by an act
of volition it is possible to double the image of an object
viewed by both eyes. By means of this power I was enabled
readily to transfer the letters of a page of your Magazine, seen
by the left (the diseased) eye, to the right of the page, and to
cause the bottom of a line of the printing seen with that eye,
to coincide with the bottom of a line viewed by the right eye,
and I could thus compare with considerable accuracy the re-
lative dimensions of the letters as seen by the diseased eye,
with those viewed by the sound eye.

To my great surprise 1 found the letters viewed by the
diseased eye to be just one half the height of those seen by
the right eye.

The size of the image formed on the retina must be in both
eyes the same, or very nearly the same, the focus of the left
eye being about nine, and that of the right eye ten inches.

From this experiment we seem necessarily led to the strange
conclusion that it is not merely by the size of the image
formed on the retina that we judge of the dimensions of ob-
jects, but that our perception of magnitude must be referred
to some other source, and that this perception is modified by
the state of the retina.

I have now lost the power of seeing any type smaller than
the words " Philosophical Magazine " in your first page, and
those words I should not be able to read did I not know them.
It may be necessary to remark, that a very strong light is so
far from assisting my vision, that in the light of the sun
scarcely a trace of these letters is perceptible.

That type the letters of which are nearly half an inch high
I can read, but it appears cloudy and indistinct. A page of

376 Mr. Sturgeon on some Magneto-electrical Experiments.

your Magazine has the appearance of a cloudy surface, the
separation of the lines being scarcely distinguishable.

If now I employ convex lenses, I find that by using a lens
of two inches' focus, I can read your Magazine with perfect
ease, the letters appearing black and distinct.

I pretend not to offer any explanation of these phenomena,
but as the facts may be relied upon, their statement may pos-
sibly tend to promote further inquiry on so interesting a sub-
ject. One practical advantage may be drawn from them, viz.
that where the power of reading is unhappily lost by amaurosis
of both eyes, it may possibly be restored by the use of a con-
vex lens of about two inches' focus.

I may add, that with the diseased eye I am able to per-
ceive the outline, though not the details, of the objects around
me.

I am, Gentlemen, yours, &c.

London, Oct. 1834. K.

LIII. Account of some Magneto- electrical Experiments made
with the large Magnet at the Exhibition Room, Adelaide-
street. By Mr. Sturgeon.

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

tTAVING obtained permission of the proprietors of the
™ ■* Exhibition Room, Adelaide-street and Lowther Arcade,
to employ their large magnet in any new experiments which
I might wish to undertake, I availed myself of that privilege
for the first time on Thursday evening the 28th of August
last. The following results were produced.

The decomposition of hydriodate of potassa in solution :
First, by paper moistened in it placed on a platinum plate at-
tached to the negative side of the circuit; and with a platinum
point connected with the positive side, the upper part of the
paper was occasionally touched, whilst the magnet was at
work. At each touch, however short the interval, iodine was
evolved at the positive point.

Second : a solution of the hydriodate and starch was placed
in a rectangular glass box, with a gauze partition to separate it
into two compartments. A platinum plate, properly con-
nected, was placed in each compartment. In half a minute
the positive cell was completely obscured by liberated iodine.
A more striking experiment was never exhibited. Platinum
wires, properly connected in the circuit, were placed in solu-

Prof. Hare's Apparatus Jor Freezing Water. 377

tion of acetate of lead : — the metal was revived on the negative
wire.

Solution of sulphate of copper was also subjected to the
action of the current. Decomposition immediately took place,
and the negative wire became completely covered with copper.

Water was also decomposed, the hydrogen and oxygen
being collected in separate tubes.

The above experiments were made by changing the con-
nexions and reversing the current ; and the results were ex-
hibited with as much promptitude as they could have been by
the employment of a voltaic battery.

Hard steel was also magnetized by being placed in a heli-
cal part of the circuit. The poles were reversed at pleasure
by changing the connexion.

A soft iron horse-shoe was magnetized to as high a degree
as by a voltaic battery.

I have also made a great variety of electro-magnetic rota-
tions, and some other rather novel motions, with electric cur-
rents by magnetic excitation, which I intend to publish as
soon as opportunity permits.

By publishing the above in the forthcoming Number of
your valuable Magazine you will much oblige

Your very obedient servant,

Artillery Place, Woolwich, W. STURGEON.

Oct. 15, 1834.

P. S. I beg permission thus publicly to acknowledge the
obligations under which I am placed for the very handsome
manner with which Mr. Payne undertook to procure me the
use of the magnet, and for the very able assistance of Mr.
Maugham, Chemical Lecturer, whilst carrying on the expe-
riments* W. S.

LIV. Apparatus for Freezing Water by the Aid of Sulphuric
Acid. By R. Hare, M.D., Professor of Chemistry in the
University of Pennsylvania* '.

T^HE congelation of water by its own vaporization, acce-
* lerated by exposure to the absorbing power of sulphuric
acid, or other agents, in vacuo, has always been a difficult
experiment. A distinguished Professor complained to me
lately of want of success in his efforts to repeat it. In. No-
vember 1832, after having three times succeeded in freezing
water by the process in question, yet having failed before
my class, I was ed to give more than usual attention to the
* Communicated by the Author.
Third Series. Vol. 5. No. 29. Nov. 1834. 3 C

378 Prof. Hare's Apparatus for Freezing Water.

process, in order to obviate the causes of disappointment. It
appeared to me that the failure arose from imperfection in
the vacuum. An excellent pump, with perfectly airtight
cocks, is indispensable; and not only must the pump be well
made, it must likewise be in good order. Neither should the
packing of the pistions, the valves, nor the cocks, allow the
slightest leakage. If a pump has been used previously for
freezing by the evaporization of aether, it will not be compe-
tent for the experiment in question, unless it be taken apart
and cleaned.

Cocks of the ordinary construction are rarely if ever per-
fectly airtight, and their imperfection always increases with
wear. Under these impressions, having cleansed my air-
pump, and put it into the best order possible ; for the purpose
of obviating leakage through the cocks associated with the
instrument, I closed the hole in the centre of the air-pump
plate by a screw, and for a receiver made use of a bell glass
with a perforated neck, furnished with a brass cap and a fe-
male screw, by means of which one of my valve cocks was
attached. A communication between the bell and the cham-
bers of my pump was established through the valve cock and
a flexible lead pipe, in a mode analogous to that already de-
scribed in the account of the valve cock. In this way I suc-
ceeded in preserving the vacuum longer than when the cocks
of the air-pump were employed in the process, and accom-
plished the congelation of water by means of the vacuum and
sulphuric acid.

Latterly, I have used an apparatus in which a brass cover
is made to close a large glass jar so as to be quite tight. In ope-
rating, the bottom of the jar was covered with sulphuric acid,
and another jar with feet, also supplied with acid enough to
make a stratum half an inch deep on the bottom, was intro-
duced as represented. The bottom of the vessel last men*
tioned was, by means of the feet, kept at such a height above
the surface of the acid in the outer jar as not to touch it.
Upon the surface of the glass vessel, a small piece of very thin
sheet brass was placed, made concave in the middle, so as to
hold a small quantity of water.

The brass cover was furnished with three valve cocks, one
communicating with the air-pump, another with a barometer
gauge, and the third with a funnel supplied with water.
Under these circumstances, having made a vacuum on a Sa-
turday, I was enabled to freeze water situated on the brass,
and to keep up the congelation till the Thursday following.
As the water in the state of ice evaporates probably as fast
as when liquid, during the night the whole quantity frozen

Zoological Society. 379

would have entirely disappeared, but for the assistance of a
watchman, whom I engaged to supply water at intervals. At
a maximum, I suppose the mass of ice was at times about two
inches square, and from a quarter to a half an inch thick.
The gradual introduction of the water, by aid of the funnel
and valve cock, also of a pipe by which it was conducted to
the cavity in the sheet brass, enabled me to accumulate a much
larger mass than I could have procured otherwise. A brass
band embracing the inner jar near the brim, with the three
straps proceeding from it, serves to keep this jar in a proper
position; that is, in fact, concentric with the outer jar.

In this last-mentioned experiment, I employed an air-pump
upon a new construction, which I have lately contrived, and
of which I shall soon publish a description.

LV. Proceedings of Learned Societies.

ZOOLOGICAL SOCIETY.

1834*. A LETTER was read addressed to the Secretary by
July 8.— <£*- M. Julien Desjardins, Corr. Memb. Z.S., dated
Mauritius, January 10, 1834. It accompanied a collection of ob-
jects of Zoology, consisting chiefly of Mammalia and Birds, which
were exhibited to the Meeting.

Mr. Gray exhibited various undescribed Shells, chiefly contained
in his own collection. He characterized them as Unio Novcb Hoi-
landice, and Anodon Parishii, penicillatus, and porcifer; the cha-
racters of each species being given in the Society's " Proceedings."

Mr. Gray also exhibited specimens of several Shells, which he
referred to a genus to be separated from Helix under the name of
Nanina. Helix (pars), Fer. Vitrina (pars,) Quoy. Animal. Col-
lare amplum, lobo dextro antico, antro respirationis in sinu posito,
lobo sinistro postico lato expanso partem inferiorem testae anfractus
ultimi tegente. Pes postice truncatus, processu brevi conico dor-
sali supra truncaturam sito. Testa depressa, perforata, polita ;
apertura lunata ; peristomate tenui, edentulo, costa interna vel
nulla vel obsoleta. India, Chinee, fyc. lncolce.

The shells comprised in this genus have been referred by M. De
Ferussac, and by most authors, to Helix : they are, however, more
nearly related to Vitrina, with which M. Quoy intends placing them.
But from the shell of Vitrina that of Nanina differs by being um-
bilicated, as well as by its smaller mouth. The lobation of the collar
of the animal of Nanina distinguishes it also from Vitrina ; the
collar of the latter being entire, with a linear lobe on the side ex-
tending over the shell, and with the respiratory hole placed at its
base.

3 C 2

380 Zoological Society.

The animal was first observed and figured by General Hardwicke
in 1797.

The following species belong to the genus:

Nan. Nemorensis. Helix Nemorensis, Midi.

Nan. Javanensis. Hel. Javanensis, Ffo.

Nan. exilis. Hel. exilis, Mull.

Nan. citrina. Hel. citrina, Linn.
Far. Hel. castanea, Mull.
Hel. Rapa, Chemn.

Nan. monozonalis. Hel. monozonalis, Lam*

Nan. Clairvillia. Hel. Clairvillia, Fer.

Nan. Vitrinoides. Hel. Vitrinoides, Desk.

Nanina Juliana. Nan. testd solidd, albd ; spird convexiusculd ;
anfractibus depressis fascid mediand brunned, ultimo antice roseo
fascid brunned axin cingente ; peristomate rotundato, roseo.

Axis 1 1, diam. 20 lin.

Hab. in Ceylon.

This is one of the most beautiful of the genus. It approaches to
Nan. Javanensis, but is thicker and larger.

Nanina striata. Nan. testd solidiusculd, subpellucidd, albidd ;
periostracd tenui, olivaced ; spird convexiusculd, confertim trans-
verse striatd j anfractu ultimo antice sublavi.

Axis 9, diam. 15 lin.

Mr. Gray also exhibited an extensive series of Shells ot the Genus
Terebra, forming part of his own collection, and illustrating an
account of many new species of that group which he presented.

He stated that the animal has a small foot, and a very long 'pro-
boscis, at the base of which are seated two very small tentacular the
operculum is ovate, thin, horny, rounded behind, and rather taper-
ing in front. The shell is covered by a very thin, pellucid, horn-
coloured periostraca : it is usually white, variously streaked with
brown, the streaks being often interrupted or broken into spots
by the two spiral bands of the shell -} one of these bands is placed
near the spiral groove and the other on the middle of the whorl. The
apex of the cavity is frequently filled up by a calcareous deposition j
but this deposition has never been observed in Ter. duplicata.

The species may be divided into the following sections :

I. Anfractibus sulco spirali cingulum posterius efformante ; labio in-
teriore tenui, concavo.

Obs. Cingulum in junioribus magis conspicuum j labium internum
in adultis rarissimk incrassatum.

Huic sectioni referendae sunt

Ter. maculata, Lam.

Ter. tigrina. — Buccinum felinum, Dillw.

Ter. strigata, Sow. — Buccinum elongatum, Wood, Suppl.,f. 22.

Ter. dimidiata, Lam.

Ter. striatula, Lam.

Ter.Jlammea, Lam.

Ter. muscaria, Lam.

Ter. subulata, Lam.

Zoological Society. 38 1

Ter. oculata, Lam.
Ter. crenulata, Lam.
Ter. corrugata, Lam.
Ter. duplicata, Lam.

Ter.pertusa, Sow. Born, Mus., t. 10. f. 13.
Ter. nubeculata, Sow.
Ter. myuros, Lam.

The following new species also belong to this section, Ter. Knorrii
(differing from Ter. maculata by being more slender, and by having
the front of the whorls spotted ; and from Ter. tigrina by the mar-
bling of the back of the whorls), affinis (allied to Ter. nubeculata,
but smaller and more slender in its proportions), rudis, striata (re-
sembles Ter. affinis, but the grooves not punctate), undulata, alba,
Jlava, punctatostriata, gracilis, tessellata (differs from all the other
spotted species by the hinder belt being destitute of spots), variegata,
plicata, punctata, Uevigata, and Icevis.

II. Anfractibus sulco spirali cingulum posterius efformante ; labio

interiore incrassato subelevato.
Obs. Quoad aperturam Cerithia quodammodo simulantes.
Huic sectioni referenda? sunt
Ter. cerithina, Lam.

Ter. tricolor, Sow.— 7b". tceniolata, Quoy, cui proprii sunt insuper
sulcum cingulum efformantem sulci alii spirales duo.

Also the following new species : Ter. anomala, ornata, cancellata,
straminea, and triseriata.

III. Anfractibus sulco postico nullo.
* Labio interiore tenui.
a. Testa elongatd, gracili.
Ter. lanceolata, Lam.
Ter. strigillata, Lam.

Ter. hastata, Lam. — Ter. costata, Mcench.
And a new species, Ter. albida.

b. Testa brevi.
Ter. aciculata. — Buccinum aciculatum, Lam.
Ter. polita. — Buccinum politum, Lam.

** Labio interiore incrassato, elevato ; testd brevi.
Obs. Nassce quodammodo affines j sed neque labium internum di-
latatum, nee externum incrassatum.

Ter. lineolata, Sow. Wood, Suppl., f. 22.

Ter. Tahitensis. — Buccinum Tahitense, Gmel. — Buccinum Au-
strale, Sow.

Mr. Gray concluded by stating that specimens of all the species
of Terebra enumerated by him are contained either in his private
collection or in the British Museum.

Mr. Gray also exhibited an extensive series of land and fresh-
water Shells which he regarded as hitherto undescribed. He cha-
racterized them as Helicophanta Falconeri, Reeve, MSS., Zonites
Walkeri, and Bulimus atomatus.

The three following species were discovered in the interior of
New Holland by Mr. Allan Cunningham, and two of them have

382 Zoological Society.

been figured, but not described, in Mr. Griffith's Edition of Cuvier's
' Animal Kingdom.' viz. Helix Cunning hami, Gray, in Griff. Anim.
Kingd., t. 6. f. 4. ; Fraseri, Gray, in Griff. Anim. Kingd., t. 6. f. 6. ;
and Jacksoniensis (resembles Hel. nitida in form, but is imperforate).
To Mr. Cunningham Mr. Gray was also indebted for three species
discovered by him in Phillip's Island, a small island about 5 miles
South of Norfolk Island. These he characterized as Hel. Campbellii,
and Phillipii — (this species is allied to the former in the shape of
the mouth and structure of the lip ; but the whorls are angular in
the young state only, as in most of the Helices of Lamarck,) — and
Carocolla Stoddartii.

The remaining species were described from specimens in Mr.
Gray's own collection; they were characterized as Bulimus rhodo-
stomus, crassilabris, apiculatus (resembles Bui. Kingii, but is more
solid and has a dark apex and pillar), Pullus, and Burchellii ; Lignus
tenuis, Helix Codringtonii, Jidelis, Cracherodii (perhaps aNanina,
but is more largely perforated than any of that genus of which Mr.
Gray has seen the animal), and Maderaspatana.

While on the subject of Indian Helices, Mr. Gray remarked that
Hel. ligulata, Fe>., Moll., t. 31. f. 2, 3, is a common Indian species;
and that Hel. cicatricosa, Chemn., vol. ix. t. 109. f. 913, is found in
the more elevated regions of India, and has lately been described by
Mr. Lea under the name of Hel. Himalayana.

Also Carocolla Nova Hollandice, Helix granifera and pachy-
gastra.

Mr. Gray observed, when characterizing the last-named shell, that
he calls that a tooth which is solid, and that a plait which is
marked externally by a corresponding groove. Thus the Chondri
of Cuvier have toothed mouths, and the Pupce and Clausilia
plaited.

The exhibition was resumed of the new species of Shells contained
in the collection formed by Mr. Cuming, chiefly on the Western
Coast of South America and among the islands of the South Pacific
Ocean. Those brought on the present occasion under the notice of
the Society were accompanied by observations and characters by Mr.
G. B. Sowerby, and comprised the following species of the genus
Pholas, the characters of which are given in the Proceedings.

" The utmost caution is necessary in the examination and de-
scription of the various sorts of Pholades, on account of the extraor-
dinary difference in the form of the same species in different stages
of growth. The addition of accessory valves also, as they increase
in age, must be carefully observed, in order to guard against too
implicit a confidence in their number and form. And though I
might be considered guilty of asserting a truism by stating that the
difference in size of different individuals of the same species may
and sometimes does mislead the tyro in the science of Malacology ;
lest such difference should mislead the adept also, let him too pro-
ceed cautiously, and when he finds a fully grown shell of half an inch
in length agreeing perfectly in proportions and characters with an-
other of two inches long, let him not conclude that it is a distinct

Zoological Society. S83

species, but if he can find no other difference except that which
exists in their dimensions, let him consider the one a giant, the other
a dwarf. Let it be remembered that among the Cyprcecz it is not un-
common to observe young shells of three inches in length, and fully
grown ones of the same sort only one inch in length ; likewise, of
the well-known British Pholades there are individuals quite in a
young state of two inches in length, and perfectly formed shells of
the same species not more than half an inch long. For an instance
in demonstration I need only refer to the Phol. papyraceus, so
abundant at Torquay, of which the young shells have been considered
by many as a distinct species and have been named by Dr. Turton
Phol. lamellosus. This varies in size exceedingly, so that it may
be obtained both in an incomplete and young state and in a fully
grown condition from half an inch to nearly two inches in length.
The circumstance of its having rarely occurred in an intermediate
state of growth, when the anterior opening is only partly closed
and the accessory valves only partly formed, led Dr. Turton and
others to persist in regarding the young and old as two distinct
species. Other similar instances will be shown in the course of the
present concise account of some hitherto undescribed species of the
same genus brought to England by Mr. Cuming." — G. B. S.

Pholas crvciger, Chiloensis, var. parva, subtruncata (very like
our British Pholas parva), calva, Gray, MSS., calva, var. nana, acu-
minata.

One specimen of the last-named shell in Mr. Cuming's collection
merits particular notice. It demonstrates a fact of considerable im-
portance to geologists. It is in argillaceous limestone, very much re-
sembling lias, and in forming the cavity in which it resides, it has,
by such chemical process as frequently takes place, absorbed a much
greater quantity of the rock than could be retained or converted ;
this is again deposited at the upper part of the cavity; and thus the
rock is recomposed. — G. B. S.

Phol. melanura, tubifera (resembling in a marked manner the
Pholas papyracea of Southern Devonshire), Quadra, Quadra, var.
(with the epidermis which covered the muscle contained in the con-
cave reflected anterior dorsal margin changed into calcareous matter),
curta, and cornea.

The whole of the Toucans of the Society's collection were exhi-
bited in illustration of an account given by Mr. Gould, at the re-
quest of the Chairman, of the species of Ramphastos, 111., and Ptero-
glossus, Ej., constituting the family Ramphastida. Mr. Gould's
attention having been of late particularly directed to this family in
the preparation of a Monograph of it, illustrated by coloured figures
of all the birds comprised in it, he was enabled to state the existence
of the under-mentioned species of the Fam. Ramphastid^e, Vig.
Rostrum magnum, ad basin nudum ; tomiis serratis. Lingua pecti-
nata. Pedes scansorii.

Genus Ramphastos, ///. Ramphastos (pars),Xmw. Rostrum max-
imum. Nares frontales, prope basin maxillae sitae. Cauda aequalis.

Nigri, torque pectorali tectricibusque caudae inferioribus coccineis , pe-

384- Zoological Society,

dibits cceruleis. Rostrum, guttur, tectrices cauda superiores, orbita-
que nuda discolores.

* Cauda tectricibus superioribus flavis.

Ramph. erythrorhynchus, Gmel., Cuvieri,Wa,g\.,culminatus, Gould.
** Cauda tectricibus superioribus albis.

Ramph. Swainsonii, Gould, carinatus, Swains., Toco, Gmel.
*** Cauda tectricibus superioribus coccineis.

Ramph. vitellinus, 111., Ariel, Vig., dicolorus, Linn.

Genus Pteroglossus, ///. Rostrum magnum. Nares superse, in
maxillse basi sitae. Cauda gradata.

SuprcL viridescentes , uropygio (nisi in perpaucis) discolore ; subths,
capite, collo, rostro, orbitisque nudis utplurimum discoloribus ; pe-
des coerulei.

Pter. Aracari, 111., regalis, Licht., castanotis, Gould, bitorqua-
tus, Vig., Azarce, Wagl., ulocomus, Gould, hypoglaucus, Gould,
Bailloni, Wagl., viridis, 111., inscriptus, Swains., maculirostris, Licht.,
Culik, Wagl., prasinus, Licht., and sulcatus, Swains.

The whole of the species characterized above are figured in Mr.
Gould's 'Monograph of the Ramphastidae,' which is just completed;
and all of them, with the exception of Pteroglossus Azarce, Pter. in-
scriptus, and Pter. prasinus, are contained in the Society's collec-
tion, and were exhibited to the Meeting.

July 22. — A letter was read, addressed to Mr. Vigors by B. H.
Hodgson, Esq., Corr. Memb. Z.S., and dated Nepal Residency, Fe-
bruary 14, 1834'. It referred to various living animals which it is the
intention of the writer to forward to Calcutta for transmission to En-
gland during the ensuing season. It also referred to a collection of
skins of Mammalia and Birds which have already been dispatched
by Mr. Hodgson for the Society. Among them are skins of the Chiru
Antelope, Antilope Hodgsonii, Abel, male and female ; and the writer
refers to these as elucidating the points which had been unascer-
tained by him at the time of making to the Society his several pre-
vious communications, abstracts of which have been published in
the Proceedings of the Committee of Science and Correspondence,
Part i. p. 52, and Part ii. p. 14 j and in the Proceedings of the So-
ciety, Part i. p. 110. An abstract of part of the letter is given in
the Proceedings, No. xix.

Some extracts were read from a Letter addressed by the Presi-
dent, Lord Stanley, to the Secretary, giving an account of the
breeding of several Birds in His Lordship's Menagerie at Knowsley.
The red Grosbeak, Loxia Cardinalis, Linn., has a nest of three young
which are nearly fledged ; and a single young one of the Tovohee
Bunting, Emberiza erythrophthalma , Gmel., has been hatched. The
Loxia cucullata has this year, as last year also, made a nest and laid
one egg ; and the American yellow Bird, Fringilla tristis, Linn., is
now sitting.

The gosling of the Sandwich Island Goose, respecting which
a notice from Lord Stanley was read on May 27, "is now
fully as large as the parents, and nearly resembles them in plu-
mage j the only differences being about the neck, which is more

Zoological Society. 385

indistinct in front and wants the full extension of the black
down the nape, and the collar at the bottom just above the
breast is only faintly marked. The legs also are as yet of a dirty
greenish yellow tinge. It is not pinioned, but has hitherto shown
no wish to use its wings. In fact they are the tamest of the tame,
scarcely will move out of one's way if in the walks, and are con-
stantly coming into the building, even more familiarly than the
common Ducks."

A specimen was exhibited of the Manis TcmmincJcii, Smuts,
forming part of the collection made by Mr. Steedman in Southern
Africa. Mr. Bennett stated that his object in calling the attention
of the Society to it was to point out the external characteristics of
a species known to its original describer by its skeleton alone and
by a few detached scales.

It may be thus characterized:

Manis Temminckii, Smuts. Man. capite breviore ; corpore latiore,
squamis magnis, ll-seriatis ; caudci truncum longitudine subce-
quante, latitudine paullo minore, ad apicem subtruncatum vix an-

gustiore.

,9

Hab. apud Latakoo!

Long. tot. 25^- unc. ; caudce, 12 ; lat. dorsi, 8; caudee, prope
apicem, 5.

The most remarkable features of this animal are the shortness of
the head ; the breadth of the body ; and the breadth of the tail,
which is nearly equal to that of the body, and continues throughout
the greater part of its extent of nearly the same width, tapering
only slightly towards the end where it is rounded, and almost trun-
cate. In the shortness of the head and the general form of its upper
part, the Man. Temminckii bears nearly the same relation to the
Man. Javanica, as is borne by the Weasel- headed Armadillo, Da-
sypus 9-cinctus, Linn., to the six -banded, Das. 6-cinctus, Ej. Of the
eleven series of scales on the body, one on each side is ventral rather
than dorsal. The scales are very large, longitudinally striate, smooth
as though rubbed towards their hinder margin, and slightly pro-
duced into a thin, short, and rounded process: they are comparatively
few in number, the large scales of the middle line of the back from
the occiput to the tip of the tail being twenty only in number ; in
Man. pentadactyla, Linn., they are about thirty j and in Man. Ja-
vanica, Desm., they vary from about forty-five to fifty. A pecu-
liarity in the distribution of the scales of Man. Temminckii is the
cessation of the middle series of them at a short distance anterior
to the extremity of the tail, so that the last four transverse rows
consist of four scales each, each of the preceding ones having five.

Some notes by Mr. Rymer Jones of the dissection of an Agouti,
Dasyprocta Aguti, 111., were read, and are given in the Proceedings.

The animal was a male; adult; measuring 19Ath inches from
the extremity of the jaws to the root of the tail ; and weighing 4lbs.
4-ioz. Its head measured 4^V inches in length ; the tail, 1TV

Third Series. Vol.5. No. 29. ^.1834. 3D

386 British Association,

BRITISH ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE.

The following is an outline of the proceedings at the late meeting
of the British Association, holden at Edinburgh from the 8th to
the 13th of September, Sir Thomas Makdougall Brisbane,
K.C.B., F.R.S., &c, &c, President, giving the titles of the papers
and other communications which were read or received.

Section of Mathematics and General Physics.
Chairman. — Rev. W. Whewell.

A report by Mr. Challis on the theory of Capillary Attraction. —
On the Repulsion produced by Heat, as established by the contrac-
tion of Newton's rings when heat was applied to the glasses, by
Prof. Powell. — Mr. Whewell read a letter from Mr. Hailstone, ac-
companying a table of Barometrical Observations, taken at short
intervals. — Prof. Forbes read a short communication from Mr.
Christie, on a remarkable Meteorological Phenomenon observed by
him at Woolwich. — Prof. Lloyd read to the Section a portion of
his report on Physical Optics. — A paper by Mr. Challis, entitled,
Theoretical Explanations of some facts relating to the composition
of the Colours of the Spectrum. — A paper by Prof. Powell, On the
Achromatism of the Eye. — Prof. Phillips read the second Report of
the result of twelve months' experiments on the quantity of rain
falling at different elevations above the ground, made by himself
and Mr. Gray. — A paper by Prof. Stevelly, entitled, An attempt to
connect some well known phenomena in Meteorology with well
established physical principles. — The second part of a Report on
Hydraulics, containing the application of the principles of that
science to the subject of rivers, by Mr. Rennie. — On a new method
in Dynamics, by Prof. Hamilton. — On a new formof the Dipping
Needle, constructed so as to afford the means of correcting the error
of the centre of gravity, by Prof. Phillips. — Notes on the mean tempe-
rature in India, by Col. Sykes.— On Magnetical Observations under-
taken in Ireland, by Prof. Lloyd. — Sir David Brewster described to
the Meeting a remarkable coloration which he had observed in the
space included between the interior and exterior rainbow. — M.
Saumarez read a paper on Light and Colours, containing some
peculiar views respecting their nature and origin. — Mr. Ramage read
a proposal for constructing a reflecting telescope of greater magnitude
than has yet been attempted. — Dr. Knight exhibited to the Section a
method of rendering the vibrations of heated metals perceptible to the
eye. — Mr. Russell gave an account of some recent experiments on the
traction of boats on canals at great velocities. — Sir David Brewster
communicated to the Section the results of a series of experiments
on the effects of reflection from the surfaces of crystals, when some
surfaces have been altered by solution; and exhibited a number of
singular forms, produced by different crystals, or by the same crystal
under different circumstances.— Mr. Graves presented a paper on
the theory of Exponential Functions, in further illustration of a
memoir on the same subject which he had laid before the Royal

Edinburgh Meeting. 28 7

Society, and which had been printed in its Transactions. — Prof.
Hamilton explained a new method of conceiving imaginary quan-
tities, and the principles of a theory which he denominated "the
theory of conjugate functions." Prof. Hamilton stated, that he had
confirmed, by the aid of the theory, the results obtained by Mr.
Graves. — Mr. Sang stated the results of some theoretical and ex-
perimental investigations which he had made on the nature of those
curves traced by the extremities of vibrating wires fixed at the end,
and he exhibited drawings of the forms of the curves thus produced.
— On the Production and Propagation of Sound, by Dr. Williams. —
On the Visibility of the Moon in total Eclipses, by Dr. Robinson. —
On Collision, by Mr. Hodgkinson.

Section of Chemistry and Mineralogy.
Chairman. — Dr. Hope.

Mr. Johnston and Mr. Harcourt gave an account of the state of
the experiments they have respectively undertaken, on the compa-
rative analysis of Iron in the different stages of its manufacture, and
on the effects of long-continued heat. — Prof. Whewell made a com-
munication from the Committee appointed to examine the subject
of Isomorphism. — A paper was read by Dr. Charles Williams, On
a new law of Combustion, and the production of Flame at a low
temperature. — On the employment of coal-tar in connexion with
water as fuel, by Prof. Daubeny. — On the discoveries of Reichen-
bach in regard to the products of the destructive distillation of
organic substances, by Dr. Gregory*. —A notice of a large specimen
of amber from Ava, intersected by thin layers of carbonate of lime,
by Sir David Brewster. — Mr. Van der Toorn gave a determination
of the amount of water in crystallized sulphate of zinc. The total
amounts to 7 atoms, of which 6 are given off at 110° C, the other
atom remaining as a necessary constituent of the salt. From this
result he concluded that sulphates, which at a red heat give off sul-
phuric acid, contain an atom of water as an essential constituent. —
On the amount of carbonic acid in the atmosphere of the town of
Bolton, and the country around, by Mr. Watson. — On the present
state of our knowledge regarding contagion, by Dr. W. Henry.—
An analysis of the oxichloride of antimony or crystallised powder
of Algaroth, by Mr. Johnston. — The Rev. W. V. Harcourt described
the objects of the experiments now in progress under his superin-
tendence, for determining the effect of long-continued heat on
various mineral substances, and the various methods adopted by
him in disposing them beneath the iron furnaces of Yorkshire. —
Dr. Clark gave an account of Mr. Nixon's process for smelting iron
by the aid of the hot-blast, and exhibited numerical results of the
advantages derived from the new process. The saving is so great,
that the total amount of coal now necessary to produce one ton of
iron amounts only to 2 tons 14 cwt. ; whereas formerly it required
8 tons 1^ cwt., being a saving of 5 tons 8 cwt. for each ton of iron
produced. This subject was discussed at considerable length. —

* See Lond. and Edinb. Phil. Map;, vol. i. p. 402; and vol. iv. p. 390.

3D 2

388 British Associalio?i.

On the Optical characters of Minerals, by Sir David Brewster. —
An account of an investigation of the constitution of certain hvdrated
salts, by Mr. Graham. — On a new mode of liquefying the gases, by
Mr. Kemp.— On the electro-magnetic condition of mineral veins, by
Mr. Fox.— On the dimorphism of the sesqui-iodide of antimony, by
Prof. Johnston.

Section of Geology and Geography.
Chairman. — Prof. Jameson.

The Section entered upon a discussion of the views of Dr. Boase
relative to stratification, &c.,'arising out of the last year's proceedings.
■ — Dr. Rogers's Report on the Geology of North America was read,
illustrated by maps. — A Report by Mr. Stevenson, On the state of
our knowledge respecting the relative level of land and sea, and the
waste and extension of land on the east coast of England, illustrated
by charts and sections of the German Ocean. — Lord Greenock read
a paper on the coal formation of the central district of Scotland. —
A notice by Mr. Menteath on the Closeburn limestone was read,
in which an account was given of the geological, mineralogical, and
chemical characters of that deposit. — A notice was read by Mr.
Trevelyan, on fossil wood from a bed of clay lying above coal in
Suderoe, the most northern of the Faroe Islands. — Dr. Hibbert
read a paper, On the ossiferous beds contained in the basins of
the Forth, the Clyde, and the Tay. A large collection of fossils
connected with this paper were submitted to the inspection of
M. Agassiz, and became the subjects of highly important investi-
gation, and communications from him during the sittings of the
Association. — On the structure of recent and fossil Woods, by
Mr. Nicol. — Some remarks on the Geology of the Orkneys, by

Prof. Traill On the Geology of Berwickshire, by Mr. Milne. — •

Notice of some caverns containing bones near the Giant's Cause-
way? by Mr. J. Bryce. — A general view of the relation of joints
and veins, by Prof. Phillips. — A tabular view of the order of succes-
sion of various formations of great thickness, and distinct from each
other in their organic remains and mineralogical characters, which
rise from beneath the old red sandstone of England and Wales, by
R.I. Murchison, Esq. — M. Agassiz delivered some highly interesting
observations on the fossil fishes of Scotland. — On the flints found
in various parts of Aberdeenshire, and more especially in the vicinity
of Peterhead, by Dr. Knight.

Section of Natural History.
Chairman — Prof. Graham.

A report was read on the recent and present state of Zoology, by
the Rev. Leonard Jenyns, F.L.S. — Also, An account of excursions in
the neighbourhood of Quito, and towards the summits of Chimbo-
razo and Pichincha, by Colonel Hall. — Prof. Agassiz next made a
highly valuable communication upon the different species of the
genus Salmo which frequent the various rivers and lakes of Europe,
in which he reduced the species to six. — On the plurality and de-
velopment of embryos in the seeds of Coniferae, by Robert Brown,

Edinburgh Meeting. 389

V.P.L.S.— On the functions and use of the orbital glands of Birds
of the orders Natatores and Grallatores, by P. J. Selby, Esq. — On
the Birds observed and collected during an excursion in Sutherland-
shire, by P. J. Selby. — On the Fishes obtained during the same ex-
cursion, by Sir W. Jardine. — On the Insects obtained, by James
Wilson, Esq. — On a collection of Insects recently received from
Java, by James Wilson, Esq. — On the change of colour of the fruit
in a certain species of Elder, by the Rev. James Drake. — On the
cultivation of Phormium tenax in Scotland, by John Murray, Esq.
— On the progress made in researches on the secretions from the
roots of vegetables, by Dr. Dunbar. — On the distribution of the
Phenogamous plants of the Faroe Islands, by W. C. Trevelyan, Esq.
— A memoir on the propagation of Scottish Zoophytes, by Mr.
Dalzell. — Account of the Natural History of the central portion of
the great mountain range of the South of Scotland, in which arise
the sources of the Tweed, by W. Macgillivray, Esq. — On the Co-
culvs indicus of commerce, by G. Walker Arnott, Esq. — On the
head of Delphinus Deductor, on the laryngeal sac of the Reindeer,
and on a new species of Thrush from Nepaul, by Dr. Traill. — On the
transformations of the Crustacea, by J. O. Westwood, Esq. — On a
peculiar race of Men supposed to have constituted the inhabitants
of the elevated regions, situated between the 14th and 19th degrees
of south lat., in South America, by Mr. Pentland. — On some pecu-
liar secretions and elaborations, viewed in connexion with the ascent
of the sap, by John Murray, Esq. — On a new species of Pecten, by
T.Brown, Esq. — On the progress of successive vegetation, at various
heights, on the Himalaya Mountains, by J. F. Royle, Esq. — Some
observations on the structure of Feathers, by Sir David Brewster.

Section of Anatomy and Medicine.
Chairman — Dr. Abercrombie.

Mr. Broughton read to the Section the results of an experimental
inquiry respecting the sensibilities of the nerves of the brain. — Dr.
Alison read a notice of some experiments by Dr. J. Reid, illus-
trating the connexion of the irritability of muscles with the nervous
system, with observations by himself. — On certain peculiarities in
the circulation of the Porpoise, illustrated with preparations, by Dr.
Sharpey. — A communication from Mr. Murray of Hullon the change
of colour in the Chameleon. — An abstract of a registry kept in the
Lying-in Hospital of Great Britain-street, Dublin, from the year
1758 to the end of 1833, and which illustrated the importance of
thorough ventilation in such establishments, by Dr. Joseph Clarke
of Dublin. The author died in Edinburgh during the meeting of the
Association. — Dr. W. Thomson read a paper on the infiltration of
the lungs with black matter, and on black expectoration, occurring
in coal-miners, iron-moulders, &c. — Sir C. Bell delivered a dis-
course explanatory of his views of the functions of the nervous sy-
stem, and of the manner in which this department of physiology
should be studied. — On the varieties of mechanism by which the
blood may be accelerated or retarded in the arterial and venous
systems of the Mammalia, by Dr. Aitkin. — Dr. Hodgkin read a re-

390 British Association.

port on the history of the results of the experimental inquiry
respecting the action of poisons, the prosecution of which was com-
mitted by the Association at its last meeting to himself and Dr.
Roupell. — Report on the present state of physiological science, by
Prof. Clarke.

The last Meeting of the Association was held in the large and
splendid hall of the college library, the galleries of which were set
apart for the accommodation of ladies. The doors were thrown
open about half- past two o'clock, when a great rush was made for
admission ; and a little after three o'clock, when the business com-
menced, the hall was tilled. A short time before this the Lord
High Chancellor Brougham made his appearance on the platform.

It was announced to the Meeting by the President, Sir Thomas
Makdougal Brisbane, that invitations to the British Association
had been received from the Bristol Institution, the Literary and
Philosophical Society of Liverpool, the Royal Dublin Society, the
Royal Irish Academy, the Geological Society of Dublin, and the
University of Dublin. At the final Meeting it was announced that
the General Committee had unanimously resolved that the invita-
tions of the constituted scientific authorities in Dublin should be
accepted j and that the next Meeting of the Association should be
held in Dublin, on Monday 10th August, 1835 ; and that the thanks
of the Association had been voted to the Bristol Institution, and to
the Literary and Philosophical Society of Liverpool, from whom
invitations had also been received ; and the Rev. Vernon Harcourt,
General Secretary, stated the results of the proceedings of the Ge-
neral Committee on the subjects brought before them for considera-
tion by the Sectional Committees, as to grants of money, requests
for reports on the progress of science, and recommendations of spe-
cial subjects of scientific inquiry. They had authorized the appro-
priation of part of the funds of the Association for the purpose of
prosecuting particular researches in physical, chemical, geological,
zoological, botanical, and medical science, to the extent of 830/.
They had authorized the application for the continuation of Reports
on various branches of science to Rev. G. Peacock, Rev. J. Challis,
Rev. R. Willis, Mr. George Rennie, Prof. Rogers, and Mr. Steven-
son ; for a Report on the application of mathematical science to the
phenomena of heat, electricity, and magnetism ; on electro-
chemistry and electro-magnetism, to Dr. Rogetj on the zoology of
North America, to Dr. Richardson ; on the botany of North
America, to Prof. Hooker; on the geographical distribution of
plants, to Prof. Henslow j on the geographical distribution of in-
sects, to Mr. J. Wilson ; on the pathology of the nervous system,
to Dr. W. Charles Henry ; and on the effect of circumstances of
vegetation on the medicinal virtues of plants, to Dr. Christison.

Various recommendations of special subjects for inquiry were
sanctioned by the General Committee, and ordered to be printed in
the next volume of the publication of the Association.

C 391 ]

LVI. Intelligence and Miscellaneous Articles.

OXIDE OF CARIJON FREE FROM CARBONIC ACID.

DR. MITCHELL states that he has obtained oxide of carbon of ex-
cellent quality, independently of the use of lime water or any
other agent for the purpose of detaching carbonic acid, by the action of
sulphuric acid on the oxalate of ammonia. The process is as follows:
Take an ounce of the oxalate, reduced to powder, and a drachm or
two of sulphuric acid, and put them into a six-ounce tubulated retort,
and apply a very gentle heat. In a few minutes large quantities of
gas are evolved, and may be collected in the usual manner over water.
If the heat be duly moderated, the first and last products, as obtained
in the receivers, will be pure carbonic oxide gas. The sulphuric acid
seems to act by resolving the oxalate into oxalic acid and ammonia j
then to decompose the oxalic acid into its elements, and to put the
whole into such a state as to enable the constituents to recombine so
as to form the pure gas. That carbonic acid is actually evolved, can-
not be doubted, but it seems to join the ammonia instantly, forming
carbonate of ammonia, which is absorbed by the water as fast as it is
produced. If it is inquired how it happens that the sulphuric acid
does not instantly seize the ammonia and form a sulphate, Dr. M. ob-
serves, that although the moderate heat employed is amply sufficient
to drive over the gaseous elements of the oxalate, it is inadequate to
cause the sulphuric acid to do so.

The above statement will be better understood by the use of a dia-
gram j premising, that the equivalents or combining numbers of the
several articles are as follow: oxalic acid 36, made up of 24, or 3
equivalents of oxygen, and 12, or 2 equivalents of carbon; ammo-
nia \7, making the salt 53 ; carbonic acid 22, made up of 16, or 2
equivalents of oxygen, and 6, or 1 equivalent of carbon ; carbonic
oxide 14, composed of 8, or 1 equivalent of oxygen, and 6, or 1
equivalent of carbon.

' oxygen 8 14 carbonic oxide.

oxygen 8>
oxygen 8 ,
carbon 6-^

36 oxalic acid,

carbon 6^>\X

\ 39 carb.

carbon 6 -22 c. acid v

ammonia.

17 ammonia 17 am'nia

53 53

■

3
3
c

1-j

If a very gentle heat be continued for some time, the same pro-
ducts will be had, independently of the use of sulphuric acid ; but
the latter seems to accelerate the process.

When we employ oxalic acid to make the carbonic oxide gas, a
portion of carbonic acid is unavoidably formed, and must be removed
by means of lime water. In like manner, this acid gas is generated
or evolved when the oxalate of ammonia is used ; but as it combines
instantly with the ammonia, it does not contaminate the desired pro-

392 Intelligence and Miscellaneous Articles,

duct. A small portion of the carbonate of ammonia will be found
along the beak of the retort, but for the most part, it is taken up by
the water. The addition of a few drops of a solution of sulphate of
copper to the fluid, strikes a blue colour instantly, thus denoting the
presence of ammonia. On examining the residuary matter in the re-
tort, it is found to be strong sulphuric acid." Dr. M. concludes with
observing, " 1 know of no other rationale of this process, and think
it quite satisfactory. Of one thing, however, I am certain, and that
is, that no other method that I have employed, yields the gas in
question, so pure, and with so little trouble. It is therefore confidently
recommended to all operators in chemistry." — Sillimaris Journal,
vol. xxv. p. 344.

ANALYSIS OF THE BRAIN.

According to M. Couerbe, the brain, when examined with a pow-
erful microscope, appears to be composed of globules which are
slightly elliptical, and are larger in the grey substance than in the
while. These globules are coagulable by acids, like those of milk
and the blood, and by a great number of other substances.

M. Couerbe finds in the brain :

1st. A pulverulent yellow fat, ste'aroconote.

2nd. An elastic yellow fat, ce'rance'phalote.

3rd. A reddish yellow oil, e'leancephol.

4th. A white fatty matter, cerebrote.

5th. Cholestrine, choleste'rote.

Added to these are the salts found by Vauquelin, lactic acid, sulphur,
and phosphorus, which form a part of the fats above named.

Before the brain was submitted to various kinds of treatment, it was
deprived of its membranous covering and washed with cold water, in
order to separate, as nearly as possible, all the blood with which it is
always impregnated : it was then malaxated and digested in cold
aether, and all that was soluble in this fluid was dissolved by macera-
tion in repeated portions of it. The first contained but little of the
fatty matter in solution; the aether appeared merely to expel the
moisture of the brain, and they were separated together by decantation.
The second portion of aether was very rich in fatty matter, and contained
but slight traces of moisture : four macerations in aether are almost
always sufficient to dissolve all the fatty portions of the brain. After
treatment with aether, the brain was subjected to the action of boiling
alcohol of sp. gr. 0*8 1 7 : the boiling solutions were filtered every time,
and the boiling was repeated until they gave no precipitate on cool-
ing; there then remained a mere agglomerated fibrous mass, which
M. Couerbe calls nevriline.

The alcoholic solutions were mixed when cold, and filtered to se-
parate the deposit, which was washed with cold 3ether, in order to se-
parate the fat soluble in this liquid : this is susceptible of crystallizing,
and perfectly similar to that which is found in the aethereal solution,
and which is choleste'rote.

The powder obtained from the alcohol is very white and pure : it
becomes slightly translucid by drying, and has then the appearance of

Intelligence and Miscellaneous Articles. 393

purified wax. The alcohol from which this white powder precipitated,
gave more of it by evaporation, mixed with some fatty matter which
was separated by aether. The substance dissolved by the alcohol
appears to be similar to that described by Vauquelin. M. Couerbe
calls it certbrote.

Towards the end of the evaporation of the alcohol, a sort of fluid
fat is deposited, which is not the white fatty matter ; it dissolves in
aether, and is converted into oil during the spontaneous evaporation
of that fluid. The alcoholic residue contains only osmazome, a free acid,
and some inorganic salts.

The aethereal solution was distilled, in order to obtain the aether as
well as the substances which it had dissolved. These were put into
a capsule, in order to finish the expulsion of the aether. The fatty
matters obtained were in considerable quantity, and in the state of a
whitish homogeneous adhesive mass, under which there was fre-
quently whitish granular fatty matter, almost entirely formed of cere-
brote. This appearance was constant in the brains of healthy persons.
This fatty matter was then treated with a small quantity of aether,
which dissolved it entirely when free from the whitish granular fatty
matter, but only partially when that was present.

This cer£brote is always found in the mass, distinct from other ele-
ments which accompany it when extracted from healthy persons ; but,
on the contrary, sufficiently combined with them to become soluble
in a small proportion of aether, when taken from the brain of a
maniac.

When, then, aether leaves any white substance, it is separated by
the filter, and when the aether dissolves it entirely, it is to be evapo-
rated to obtain more of the substance ; the residue is to be subjected
to the action of boiling alcohol, which dissolves the three fatty matters,
among which is the c£rebrote, and leaves undissolved a yellow solid
fat resembling wax. This substance is almost totally insoluble in
alcohol : it is to be washed several times with boiling alcohol to sepa-
rate extraneous matters. The substance is not yet pure ; it contains
another peculiar yellow matter that is separated by cold aether, which
dissolves the greater part of the mass, and leaves the other portion in
the form of a brown powder. By filtering and washing this brown
powder with aether, and then evaporating the aethereal solution, both
these substances are obtained.

The portion soluble in aether is of a fawn colour : it cannot be
sufficiently dried to be pulverized. The other portion is of lighter
colour, readily dries, and is easily reduced to a fine powder by tritu-
ration. The first M. Couerbe calls ce'rance'phalote and the second
sttaroconote.

When the alcohol, holding the remaining matters in solution, is
filtered through animal charcoal, and is exposed to spontaneous eva-
poration, it deposits a considerable number of crystals, which are very
white and have a greasy lustre : they are to be pressed in fine linen,
and the alcohol by evaporation furnishes more crystals, which are to
be added to the first.

When the alcohol has been weakened by repeated evaporations, it
Third Series. Vol. 5. No. 29. Nov. 1834. 3 E

394 Intelligence and Miscellaneous Articles,

becomes turbid, and yields crystals of the same matter mixed with
red oil, which precipitates to the bottom of the vessel: it is difficult to
obtain this in a pure state. There often comes down with it some solid
matters which give it consistence, and which give it the appearance
of fat or even of several fatty matters. In order to separate the oil, it
must be subjected to a slight pressure in a cloth, and alcohol poured
upon it, which leaves the crystals. This alcohol is turbid on account
of the oil which it contains. Some aether is to be added to it, which
redissolves the oil, and renders the liquor clear, when exposed to
spontaneous evaporation. A part of the aether slowly evaporates j
the remainder holds the crystalline matter in solution, and allows the
oil, as it is formed, to precipitate to the bottom of the liquid. When
the stratum is rather thick, it is to be removed by a pipette and fil-
tered, and it is then pure and reddish. This oil M. Couerbe calls
e'leancephol, or oil of the brain.

As to the very abundant portion of the brain remaining after treat-
ment with aether and alcohol, and which the author calls n^vriline,
it is partly composed of albumen, coagulated globules, and of a mem-
branous substance soluble in potash.

Analyses of the preceding Substances.

Ce're'brote. — M. Vauquelin appears to have been acquainted with
this substance, which he has described under the name of white fatty
matter , and which has since been called myclocone by Kiihn j but ac-
cording to some of the characters which M. Vauquelin has assigned to
his white fatty matter, it seems that he did not obtain it pure, since
he says that it is fusible and viscid, whereas cerebrote is infusible,
and does not stain paper. When properly dried at a gentle heat it
becomes friable, and may be pulverized j it is soluble in boiling al-
cohol, and but slightly so when it is cold. The process for extracting
it is dependent upon this difference. It does not saponify with a so-
lution of potash or soda, a property also observed by Vauquelin.

Ce>£brote is composed of

Carbon 67-818

Hydrogen 11-100

Azote 3-399

Sulphur 2-138

Phosphorus 2332

Oxygen 13213

100-

Vauquelin does not mention the existence of sulphur in it.

Ce'rance'phalote. — This substance is solid, brown, insoluble in al-
cohol and in water, but dissolved by 25 times its weight of cold
aether. It softens by heat, and without becoming perfectly fluid : when
dried it is elastic, like caoutchouc. M. Vauquelin has not mentioned
this substance, but Kiihn appears to have had a glimpse of it. Sul-
phuric acid attacks it with great difficulty: nitric acid reduces it to
its elements, and converts the sulphur and phosphorus into acids.

Intelligence and Miscellaneous Articles, 395

It is composed of

Carbon 66*362

Hydrogen 10-034

Azote 3*250

Phosphorus 2*544

Sulphur 1*959

Oxygen 15*851

100-
Stiaroconote, — This is a fatty matter, which occurs mixed with
the preceding. It is of a fawn colour, infusible and insipid, and by
combustion gives an acid charcoal. Neither alcohol nor aether dissolves
this substance ; both the fixed and volatile oils readily dissolve it.
Nitric acid takes it up after slight ebullition, and it reappears as a
white fat, which is acid, soluble in boiling alcohol, and crystallizes in
small laminae, similar to margaric and stearic acids.
This substance is composed of

Carbon 59-832

Hydrogen 9'246

Azote 9-352

Phosphorus 2420

Sulphur 2030

Oxygen 17*110

99-990
Eliancephol. — This is a reddish liquid ; its taste is disagreeable : it
is soluble in aether, fixed and volatile oils, and alcohol, in all propor-
tions. When heated, this substance dissolves the other matters of the
brain readily, and these impart consistence to it. Its composition is
similar to the preceding.

Cerebral Choleslerine. — A crystallizable fatty matter, which, accord-
ing to some authors, must be the result of some morbid change. The
constant and considerable quantity which M. Couerbe found in the
brain induces the belief that it is a widely diffused organic animal ele-
ment. It is well known that MM. Denis and Boudet have found it in
the blood. The cerebral cholesterine is perfectly similar to that of
biliary calculi. Their analyses gave M. Couerbe the same results :

Carbon 84*895

Hydrogen 12*099

Oxygen 3006

100-
This analysis differs a little from that of M. Chevreul, as follows :

Carbon 85-095

Hydrogen 11-880

Oxygen 3-025

100-
Journal de Chimie Medicale, Sept. J 834.

3 E2

396 Intelligence and Miscellaneous Articles.

VALERIANIC ACID AND ITS SALTS.

It is well known that M. Grote discovered in the distilled water of
valerian an acid, which has been examined by M. Peatz (Berzelius,
Traite de Chimie, tome v. p. 98). M. Tromsdorff has made some new
observations respecting this acid.

Valerianic acid is liquid, colourless, limpid, and oleaginous. Its
smell strongly resembles that of the root and the essential oil of the
Valeriana officinalis : the odour is diminished when the acid is com-
bined with a base, but it is never totally lost. The taste of valerianic
acid is very strong, very acid, unpleasant, and permanent. If the acid
is diluted, it leaves a sweetish after-taste. Its sp. gr. is about 0*944 ;
it remains fluid at 0° Fahr. : it burns, without leaving any residue,
with an intense flame ; when heated to about 270° it boils ; it is
soluble in 30 parts of water at 54° ; alcohol dissolves it in. all pro-
portions, but neither olive oil nor oil of turpentine • it is very soluble
in concentrated acetic acid of sp. gr. 1*07 ; cold sulphuric acid renders
it yellow, and decomposes it when hot, sulphurous acid being evolved ;
nitric acid, even when hot, has not much action upon it.

According to M. Effling, it is composed of

Carbon 6496 or 10 atoms = 76437

Hydrogen.... 9'54 — 18 = 112-31

Oxygen 25-50 — 3 = 30000

100- 1176*68

Valerianic acid is prepared by agitating the essential oil of valerian
with carbonate of magnesia and water. The mixture is to be after-
wards distilled, and by this an oil is obtained which is no longer acid,
and the odour of which is less strong than the original oil : a proper
quantity of sulphuric acid is to be added to the liquid which remains
in the retort, and the distillation is to be repeated. The valerianate is
decomposed, and the valerianic acid distils.

Valerianic acid may also be obtained by another process, described in
the work of Berzelius. It consists in saturating the distilled water of
valerian with carbonate of potash or of soda ; distilling to separate
the oil ; then decomposing with sulphuric acid, to obtain the valerianic
acid by distillation.

The oil of valerian may also be treated with potash or soda j then
separating the oil, and afterwards the acid.

The valerianates have a peculiar odour ; a sweet taste, followed by
a sharp one. Some of these salts are unalterable when exposed to the
air, some efflorescent, and others deliquescent j they crystallize with
different degrees of facility -, they are greasy to the touch, and of dif-
ferent degrees of solubility in water j by heat they are decomposed,
but there is first a disengagement of a small quantity of acid, which is
volatilized without alteration. The stronger acids separate the valeri-
anic acid from its combinations, and this acid decomposes the ben-
zoates and the carbonates.

The valerianates of potash and soda are deliquescent ; the valeri-
anate of zinc crystallizes in laminoe during the cooling of a hot solu-

Intelligence and Miscellaneous Articles, 397

tion, but by spontaneous evaporation acicular crystals are obtained.
Valerianate of barytes is an amorphous mass, unalterable in the air;
the valerianates of lime and magnesia crystallize in needles, which
are not deliquescent. Valerianate of lead deposits in laminar cry-
stals from a hot solution : by evaporating the liquor a thick syrupy
fluid is obtained.

With the oxides of mercury valerianic acid forms two salts. The
protovalerianate is but little soluble ; a saturated boiling solution
deposits small needles on cooling. The pervalerianate of mercury is
much more soluble : if the solution is boiled with an excess of prot-
oxide, a bright yellow pulverulent subsalt is deposited on standing. —
Journal de Chimie Medicate, Sept. 1834, p. 473.

HYDROCYANIC iETHER.

M. Pelouze obtained this compound by the action of heat upon a
mixture of sulphovinate of barytes and cyanuret of potassium. This
aether is colourless ; has a strong alliaceous smell, is extremely dele-
terious to the animal ceconomy; inflammable j boils at 1 76° Fahr. ;
its density is 0787 ; is very slightly soluble in water, but combines
with alcohol and sulphuric aether in all proportions. It does not pre-
cipitate nitrate of silver ; in which respect it resembles muriatic aether,
which does not decompose this salt until it has been previously de-
stroyed by the action of heat.

Hydrocyanic aether is formed of equal volumes of olefiant gas and
cyanogen, condensed to one half : this is indicated by direct analysis
and the density of its vapour. — lbid.t p. 486.

DISTILLATION OF TARTARIC AND PYROTARTARIC ACIDS.

M. Pelouze finds that tartaric acid, like other vegetable acids,
yields very different products, and in very variable quantity, according
to the temperature employed in its distillation.

With a naked fire there are obtained empyreumatic oil, olefiant
gas, water, carbonic acid, acetic acid almost crystallizable on account
of its great concentration, and a quantity of pyrotartaric acid so
small and so mixed with other products that it is difficult to separate
it. From about 400° to 570° Fahr. the same products are obtained,
but in very different proportions, and the pyrotartaric acid is much
more abundant: between 350° and 375° the proportions of pyrotar-
taric acid and acetic acid increase still more than the traces of empy-
reumatic oil j but there are sensible quantities of acetic [carbonic ?]
acid, carburetted hydrogen, and carbon. By evaporating the product
of this distillation crystals are obtained, which it is possible to purify,
but by a long and delicate operation. The following is the best
process :

Put the compound liquid in which the pyrotartaric acid is dissolved
into a glass retort, and distil until the residue has acquired a syrupy
consistence ; then change the receiver, and continue the distillation
to dryness ; expose the liquor last distilled to a very low temperature,
or to spontaneous evaporation in vacuo. In both cases irregular yel-

898 Intelligence and Miscellaneous Articles.

lowish crystals are obtained, of an empyreumatic odour \ these are to
be pressed between several folds of filtering paper j they are then to
be redissolved in water, and the boiling solution treated with animal
charcoal. By these means pure crystals of pyrotartaric acid are
obtained on cooling.

Pyrotartaric acid obtained by this process has the following pro-
perties : It is white, inodorous, very soluble in alcohol, strongly sour
to the taste, like tartaric acid itself. It is fusible at about 212° Fahr.,
it boils at 360° ; and as it decomposes at a temperature a little higher
than this, it is difficult to volatilize it without leaving a residue.

A concentrated solution of this acid does not render lime, barytes,
or strontia water turbid ; it forms in a solution of acetate of lead a
very abundant white precipitate, insoluble in water, but very soluble
in an excess of acetate ; it does not precipitate either neutral acetate
or nitrate of lead. None of the following salts are precipitated by free
pyrotartaric acid : proto- and per-salts of mercury, persulphate of iron,
the salts of lime and barytes, the sulphates of zinc, manganese, and
copper. The neutral pyrotartrate of potash is a deliquescent salt.
Pyrotartaric acid is represented by C3, H8, Ol; by combining with
bases it loses an atom of water, and becomes O, H6, O3. — Journal de
Chimie Medicate, Sept. 1834, p. 497.

ON THE EXISTENCE OF TITANIUM IN ORGANIC MATTER. BY
MR. G. O. REES.

To the Editors of the Philosophical Magazine and Journal of Science,
Gentlemen,

Being lately engaged in the chemical examination of the organs of
the human body, I was struck by a peculiar yellow colour which the
salts of the renal capsules afforded when subjected to a red heat, this
colour gradually disappearing as the mass (which was a fused one)
cooled. In order to investigate the cause of this phenomenon, the
following experiments were made t

1st. The mass was digested and boiled in water, and the aqueous
solution being decanted, was tested with hydrosulphuret of ammonia,
which, after a few minutes had elapsed, afforded a scanty dark green
precipitate. I now began to suspect the presence of titanium.

2nd. That portion of salts which was insoluble in water was di-
gested in dilute hydrochloric acid ; and the solution being neutralized
by ammonia, and tested with the hydrosulphuret, afforded a copious
dark green precipitate. A second portion of this acid solution was
tested with infusion of galls, which produced a reddish brown preci-
pitate, care having been taken to neutralize the excess of acid.

3rd. The matter which was insoluble in water and acid was tested
on platina and charcoal before the blowpipe, and afforded a yellow
transparent bead in the outer flame, which became of a dark purple
colour when heated in the inner flame.

4th. The green sulphuret, on being exposed to heat, afforded a
white powder ; and a similar effect resulted on exposing it for seven
or eight days in the liquor from which it was precipitated.

Intelligence and Miscellaneous Articles, 399

Some specimens of renal capsule contain but a small proportion of
alkaline salts, and will not so easily produce the yellow colour which
first attracted my attention, unless an alkaline matter be supplied to
them. I have examined several specimens of the salts contained in
these glands, and have always procured similar precipitates and re-
actions, which, when compared side by side with those produced by
titanic acid, show a most unequivocal and perfect resemblance.

It would appear that these salts contain an alkaline titanate, be-
sides a portion of free titanic acid, there not being sufficiency of alkali
to act on all the acid present.

In two or three specimens which I have examined the salts have
appeared quite black and carbonaceous in appearance ; but fusion
with phosphate of soda or carbonated alkali has always rendered the
yellow colour visible. These black ashes exert an alkaline reaction on
reddened litmus paper.

It may be noticed that the precipitate procured with infusion of
galls is influenced in its colour, not only by the quantity of acid pre-
sent, but very materially by the degree of concentration of the infusion
and solution.

From other experiments lately made, I have reason to believe that
titanium exists in other structures besides the renal capsules.

G. O. Rees.

Guy's Hospital, Oct. 3, 1834.

CRYSTALLIZATION OF KALIUM OR POTASSIUM.

Upon unscrewing the lid of a crucible from which a portion of
kalium had been distilled, Professor Pleischl found a fragment of
kalium lying upon the remaining carbonaceous mass, curved in such
a manner as to lead to the conclusion that it had fallen out of the
gun- barrel used in the operation. The concave side of this frag-
ment when examined with a powerful lens under a layer of naphtha,
exhibited small projecting crystals, the faces of which were all at
right angles to each other, strongly resembling those of artificially
crystallized bismuth. Professor Pleischl convinced himself that
the crystals were kalium by throwing some of them into water, upon
which they immediately took fire, burning with a violet flame. —
Baumgiirtner's Zeitschrift, band iii. S. 1.

SCIENTIFIC BOOKS.

Just published,
A Guide to Geology. By Prof. Phillips.

The Calendar for 1834-35 of the Meetings of the Scien-
tific Bodies of London, showing the Time and Place of the
Meetings of the principal Learned Societies, — with their Anni-
versaries, and the Hours at which their Libraries and Museums
are open. To be had at the Office of the Lond. and Edinb. Phil.
Mag. and Journal.

Remarks.

1

London. — Sept. 1. Cloudy: rain. 2. Fine.
3. Hazy. 4. Very fine. 5. Overcast: fine.
6. Fine. 7. Hazy. 8. Heavy rain. 9. Over-
cast: fine. 10. Overcast: rain. 11. Hazy:
rain. 12. Heavy dew : fine. 13 — 25. Very
fine : the mornings generally foggy. 26. Slight
rain. 27. Rain: fine. 28. Hazy : fine.
29, 30. Foggy : very fine. — A finer month of Sep-
tember is, perhaps, not in remembrance.

Boston.— Sept. 1. Fine : rain p.m. 2. Fine.
3. Cloudy. 4. Cloudy ; thermometer at
4 p.m. 75° : rain with thunder and lightning p.m.
5. Cloudy. 6. Fine : rain p.m. 7. Cloudy:
rain p.m. 8. Cloudy. 9. Cloudy: rain early a.m.
10. Cloudy : rain p.m. 11. Fine : rain p.m.
12. Cloudy. 13— 16. Fine. 17. Fine: ther-
mometer 3 p.m. 77°. 18. Foggy. 19, 20. Fine.
21 — 25. Cloudy. 26. Cloudy : rain p.m.
27. Rain. 28. Fine. 29, 30. Cloudy.

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THE

LONDON and EDINBURGH

PHILOSOPHICAL MAGAZINE

AND

JOURNAL OF SCIENCE.

[THIRD SERIES.]

DECEMBER 1834.

LVII. On Phosphuretted Hydrogen. By Thomas Graham,
F.R.S. Edin.9 Anderson-tan Professor of Chemistry, and
Vice-President of the Philosophical Society of Glasgow.*

"C^EW substances have been made the subject of experi-
-*- mental inquiry more frequently than the compounds of
phosphorus and hydrogen, and none are so remarkable for
the various and conflicting results which they have presented
to chemists of the greatest acuteness and practical skill. The
obscurity which long hung over the subject has been dis-
pelled, however, in a great measure, by the recent investiga-
tions of Henry Rose, of Berlin f. Although baffled in his early
inquiries, that philosopher returned again and again to the
subject, and at last succeeded in determining the chemical
functions and true constitution of phosphuretted hydrogen.
He has shown it to be analogous to ammonia in chemical
character and composition. But hitherto two compounds of
phosphorus and hydrogen had generally been admitted to
exist, which were believed to differ in composition as they do
in properties, one being spontaneously inflammable in atmo-
spheric air, and the other not so. Rose establishes beyond
all doubt that these gases are essentially of the same composi-
tion, and of the same specific gravity ; and, indeed, that they
are mutually convertible, each into the other, without any

* Communicated by the Author.

f An account of Rose's experiments on this subject, with a notice of Dr.
Dalton's anticipation of his views, will be found in Lond. and Edinb. Phil.
Mag. vol. iii. p. 308.— Edit.

Third Series. Vol. 5. No. 30. Dec. 1834. 3 F

402 Prof. Graham on Phosphurctted Hydrogen.

addition or subtraction of matter that could be perceived. In
explanation of their possession of different properties, under
the same composition, allusion is made by Rose to isomerism,
or the doctrine that two bodies may exist identical in compo-
sition, but differing in properties. Certainly the existence of
two gases constituted alike, and yet possessing different pro-
perties, if established, would afford a firm basis for this doc-
trine.

It was the importance of the theoretical results which might
be looked for, that induced me to attempt to continue the in-
vestigation beyond the point to which it has been carried by
Rose. Holding the general doctrine of isomerism as proble-
matical, my inquiries were directed to the discovery, in one or
other of the gases, of some adventitious matter, to the presence
of which the peculiarities of the species might be attributed.

It is to be understood that the spontaneously inflammable
gas made use of .in my experiments was prepared by the
well-known process of heating phosphorus, lime, and water
together. This gas is spoken of as " the self-accendible gas,"
or as " the gas from phosphuret of lime." The other gas,
which is not spontaneously inflammable, was prepared by
heating hydrated phosphorous acid, or by allowing the pre-
ceding species, contained in low receivers, to stand over water
for twenty-four hours. It is described as " the non-accendible
gas," " the gas from phosphorous acid." The accendibility
of the gas was judged of by allowing it to escape in bubbles
into the air from the receiver containing it, over either water
or mercury. The experiments were all made when the tem-
perature of the atmosphere was between 60° and 70° Fahr.

1. In the process by which the self-accendible gas is pro-
cured, free phosphorus distils over, of which a trace in the
state of vapour may well be supposed to remain in the gas for
some time. Hence the idea has generally presented itself
that the free and highly accendible phosphorus present may
be the cause of the spontaneous inflammability of the gas.
Dr. Dalton, who all along maintained the opinion, which has
finally been established by Rose, that the two gases are of
the same composition, was in the habit of referring the spon-
taneous inflammability of the one species to this cause. The
speedy loss of the property in question in the case of gas con-
fined over water seemed to favour this view. I find, however,
that if a small quantity of phosphuretted hydrogen, when not
self-accendible, be added to a confined portion of air, sticks
of phosphorus introduced into that air do not smoke, — or that
phosphorus has no disposition to combine with oxygen when
phosphuretted hydrogen is present. In a transparent mixture

Prof. Graham on Phosphurettea I Hydrogen, 430

of one volume phosphuretted hydrogen, and one thousand
volumes, or any smaller proportion whatever, of air, sticks of
phosphorus remain unaffected, but the phosphuretted hydro-
gen itself always undergoes a slow oxidation. In a mixture
of one volume phosphuretted hydrogen and two thousand air,
phosphorus smoked strongly for some time, but at a certain
period the action ceased, and long before the oxygen of the air
was exhausted. A minute proportion of phosphuretted hydro-
gen is, therefore, sufficient to protect phosphorus from oxida-
tion, in which respect this gas resembles the hydrocarburets and
essential oils, which have been shown to be equally efficacious
in protecting phosphorus from oxidation. All these bodies
appear to act in this respect in one way, namely, by taking
the precedence of phosphorus in the process of oxygenation.
Phosphorus being, therefore, less oxidable than phosphuretted
hydrogen itself, cannot be supposed to take fire, and to in-
flame the gas, or be the cause of its accendibility at low tem-
peratures.

On sending electric sparks through non-inflammable phos-
phuretted hydrogen itself, phosphorus is deposited; but the
gas, while still cloudy from the phosphorus suspended in it,
proved to be non-inflammable on passing it into air.

The loss of accendibility in the case of gas confined over
water is certainly wholly unconnected with the deposition of
any free phosphorus from the gas which may occur, but is
due to the rise of oxygen from the water into the gas. It was
observed that water which had been boiled to deprive it of all
air, and which was then passed up to self-accendible gas con-
fined over mercury, did not affect the gas in the course of
forty-eight hours. In this case, moreover, the gas was agi-
tated with the water. The gas continues in general sponta-
neously inflammable over mercury for forty-eight hours, and
sometimes for three or four days, but ceases to be so in a very
short time after the admission of a small proportion of air,
particularly if the air be added in a gradual manner. Thus,
if to the gas be passed up one twentieth part of its bulk of
cork or dry stucco, containing air in its pores, a white smoke
appears in the gas, and it ceases to be spontaneously inflam-
mable in the course of a few minutes. The same mass of
stucco, warmed before being passed up into the gas, did not
produce the same effect. The self-accendible gas always de-
posits on standing a solid matter of a lively yellow colour, con-
taining phosphorus, but in quantity too minute for analysis.
This matter is not acted on by any of the ordinary solvents,
such as alcohol, aether, alkalies, muriatic acid; but is destroyed
by chlorine-water and by nitric acid. The precipitation of
this matter is most rapid in the case of gas over water, and is
indicative of deterioration of the gas.

3 F2

404? Prof. Graham on Phosphuretted Hydrogen,

2. The self-accendible gas procured from phosphorus, water,
and lime, is always mixed with free hydrogen, varying in
quantity from 25 to 50 per cent., while the non-accendible
gas from phosphorous acid contains no hydrogen gas, but is
pure. Rose concludes, that the spontaneous inflammability
of the first species cannot depend upon this hydrogen, for
the other species is not made self-accendible by the addition
to it of any proportion of free hydrogen. On trying the ex-
periment, however, I obtained a different result. A quantity
of gas had lost its self-accendibility by standing over water
for two or three hours. To my surprise the addition to this
gas of hydrogen, in any proportion from one third of a volume
to three volumes, restored the self-accendibility of the gas.
Spontaneous inflammability was communicated likewise to the
gas procured from phosphorous acid, in some cases, merely
by adding hydrogen to it. It was perceived, however, early
in the course of the investigation, that hydrogen did not uni-
formly communicate the property in question, and that its
influence depended on something accidental, and not essential
to the gas. For instance, the hydrogen which comes over
almost pure, towards the end of the process for phosphuretted
hydrogen, itself had none of this property; nor did it appear
in hydrogen obtained from the following sources : From the
electric decomposition of water ; from the decomposition of
steam by iron; from the action of water on amalgam of potas-
sium ; or from the action of the following acids on zinc, namely,
muriatic, arsenic, and phosphoric. Even in the case of the ac-
tion of sulphuric acid on zinc or iron, which had first afforded
hydrogen possessing the property in question, it turned out
that only the hydrogen evolved at an early period of the ac-
tion is efficient, while the gas evolved after the vivacity of
the action is impaired, is nearly, and sometimes entirely, desti-
tute of any influence. The activity of the hydrogen was, in
short, traced to a slight impregnation of nitrous acid vapour
which it possessed. The sulphuric acid of commerce always
contains a small portion of some acid of nitrogen, probably
the hyponitrous, from which I find it cannot be freed by boil-
ing or concentration, continued for any length of time. On
quickly mixing sulphuric acid with two or three volumes of
water, the presence of nitrous acid is attested by its peculiar
odour, and almost certainly by the appearance of brown
fumes.

That the hydrogen did not owe the property in question to
a trace of nitric oxide, which, combining with oxygen, might
by a slight consequent evolution of heat have an effect in
kindling the phosphuretted hydrogen, was proved by the fact
that the property in question could not be imparted to hydro-
gen by any proportion of nitric oxide : but to this point there

Prof. Graham on Phosphnretted Hydrogen. 405

will be occasion to recur. At an earlier stage in the inquiry,
some experiments were made upon the effect of other gases
than hydrogen upon phosphuretted hydrogen. None, with the
exception of sulphuretted hydrogen, (evolved by the action of
sulphuric acid on sulphuret of iron, and which, therefore, con-
tains free hydrogen,) appeared to favour the accendibility of
the gas. On the contrary, the addition of all others, and even
of hydrogen and sulphuretted hydrogen themselves above a
certain proportion, distinctly impeded or destroyed the ac-
cendibility of this gas. Thus, one volume phosphuretted
hydrogen ceased to be inflammable when mixed with the fol-
lowing proportions of different gases :
With 5 volumes hydrogen.

2 — — — carbonic acid.

S nitrogen.

1 volume olefiant gas.

„* — * — & —
sulphuretted hydrogen.

T1^ nitric oxide.

^i_ muriatic acid.

£ ammoniacal gas.

It is to be remarked, however, in reference to the preceding
table, that some specimens of phosphuretted hydrogen appear
to be more highly accendible than others, and that there is
considerable latitude in the proportion of foreign gas which
may be requisite for destroying the spontaneous inflamma-
bility of a given specimen. Often a much smaller portion
suffices than is stated in the table. I have found half a vo-
lume of carbonic acid or nitrogen to have the effect in certain
cases. Of course the introduction of any trace of air with the
gases must be carefully guarded against. Nitrous acid, when
present in hydrogen in too small a proportion to enable that
gas to communicate spontaneous inflammability to phosphu-
retted hydrogen, or to be perceived by the smell, may be de-
tected by the effect of the hydrogen upon a prepared mixture
of non-accendible phosphuretted hydrogen and air, which
mixture may be had transparent and quite free from white
smoke. The addition of hydrogen to this mixture occasions
the immediate appearance of a dense white smoke, the oxida-
tion of the phosphorus being partially induced if an infini-
tesimal proportion even of nitrous acid exist in the hydrogen.
Although the oxidation of the phosphorus takes place at the
expense of the air present, and only when air is present, yet
the nitrous acid appears to be speedily consumed ; the fumes
soon ceasing, but appearing again on every subsequent addi-
tion of active hydrogen, till several volumes have been added,
or till the oxygen of the air present is exhausted.

That the influence of the hydrogen was referrible to the ni-

406 Prof. Graham On Phosphuretted Hydrogen.

trous impregnation appeared also from the fact, that phos-
phuretted hydrogen, which had lost its spontaneous inflam-
mability, was rendered as actively inflammable as ever by
passing it, bubble by bubble, into an inverted receiver filled
with sulphuric acid recently diluted with three measures of
water and cooled. The gas was now capable of igniting
spontaneously when passed into air, without the intervention
of hydrogen. The same diluted acid lost the smell of nitrous
acid by exposure to air in a shallow vessel for a few hours,
and thereafter was found unfit for the purpose in question.
Phosphuretted hydrogen which had acquired spontaneous in-
flammability from a nitrous impregnation, appeared to retain
that property as long as the phosphuretted hydrogen which is
spontaneously inflammable as first prepared. Hydrogen gas
which had received a nitrous impregnation by being passed
through a diluted sulphuric acid, retained in one case, after
being confined for twenty-four hours over water, the power
of rendering phosphuretted hydrogen spontaneously inflam-
mable.

From the preceding results and other considerations, it
seemed not unlikely that the spontaneous inflammability of
phosphuretted hydrogen may be an accidental property, and
may depend upon the occasional presence of some foreign body
in minute quantity. The inquiry suggests itself, Is there a
peculiar principle in the self-accendible gas ? and if so, what
is it?

3. It very soon appeared that a peculiar principle is with-
drawn from the gas by porous absorbents, such as wood-char-
coal and baked clay, which substances are capable of destroy-
ing the inflammability of several hundred times their volume
of gas. Thus, in one experiment, to five hundred mea-
sures of highly accendible phosphuretted hydrogen, one mea-^
sure of charcoal recently heated to redness, and cooled under
the surface of mercury, was passed up. In the course of five
minutes, a contraction of eight or ten measures occurred,
without any oxidation of the gas, for no air was introduced
with the charcoal. The gas was still spontaneously inflam-
mable, but ceased to be so in the course of half an hour. It
was found, in fact, by different experiments, that wood- char-
coal can absorb about ten times its volume of phosphuretted
hydrogen itself; that the phosphuretted hydrogen and the
peculiar principle are absorbed indiscriminately at first by
the charcoalj but that by and by the peculiar principle comes
to be entirely absorbed by the charcoal without any further
absorption of phosphuretted hydrogen. When the phosphu-
retted hydrogen did not exceed fifty or sixty times the bulk
of the charcoal, the peculiar principle was entirely withdrawn

Prof. Graham on Phosphuretted Hydrogen. 407

in five minutes, so that the gas ceased to be self-accendible.
Charcoal which had been drenched in water was without
effect upon the gas. On heating the charcoal saturated with
gas in a retort filled with water, phosphuretted hydrogen was
given off, which, however, was not self-accendible ; and all
my attempts failed to isolate the peculiar principle by sepa-
rating it from the charcoal. It was quite clear that the pecu-
liar principle formed but a very small proportion of the phos-
phuretted hydrogen, evidently much less than one per cent,
of the bulk of the gas. Spongy platinum introduced into the
gas did not exercise any sensible absorbent effect, and no
quantity of it seemed sufficient to withdraw the peculiar prin-
ciple from a small bulk of phosphuretted hydrogen. Stucco,
likewise, was without effect upon the gas, at least when access
of air was guarded against at the same time. But both of
these substances are known to possess a very low absorbent
power.

4. Phosphuretted hydrogen transferred to a receiver over
mercury, the inside of which has been moistened by a solu-
tion of caustic potash, always loses its spontaneous accendi-
bility, although by no means rapidly, several hours being ge-
nerally required.

5. Certain acids appear to have a remarkable power in
withdrawing the principle of inflammability from phosphuret-
ted hydrogen. Let phosphuretted hydrogen be transferred
into a jar inverted over mercury, of which jar the inner sur-
face has been moistened with concentrated phosphorous acid.
A small quantity of the milk-white matter immediately appears
in the acid where exposed to the gas, and in two or three
minutes the gas has ceased to be spontaneously inflammable
in air, without any appreciable diminution of its volume hav-
ing occurred. This white matter, although very sensible to
the eye, exists only in the most minute quantity. It is not
crystalline, and perhaps not even solid. The introduction of
concentrated phosphoric acid into the gas was attended by
similar phaenomena, and the gas lost its spontaneous inflam-
mability in the course of half an hour. A strong solution of
arsenic acid acts as rapidly in withdrawing the peculiar prin-
ciple as phosphorous acid does; but the arsenic acid soon be-
gins to react upon the phosphuretted hydrogen itself, a dark
copper-coloured incrustation soon forming upon the surface
of the gas-receiver, which matter is probably a phosphuret of
arsenic. Concentrated sulphuric acid is capable of absorbing
phosphuretted hydrogen itself, which the preceding acids are
not; but even sulphuric acid appears to absorb the peculiar
principle in the first instance, by a more active affinity than

408 Prof. Graham on Phosphuretted Hydrogen.

it exerts on the gas itself. Diluted phosphorous, phosphoric
and arsenic acids react in the same manner upon phos-
phuretted hydrogen, but not so rapidly as the concentrated
acids do.

6. The following liquids are capable of dissolving the quan-
tity of phosphuretted hydrogen gas placed against their names
at 65° Fahrenheit.

Alcohol (sp. gr. 850) | volume.

Sulphuric aether 2 volumes.

Oil of turpentine 3%

The essential oils and most of the hydrocarburets appear
to withdraw or to negative the peculiar principle in sponta-
neously inflammable phosphuretted hydrogen, in a rapid man-
ner. If a jar be moistened in the slightest degree with oil of
turpentine, coal-tar naphtha, or with the liquid distilled from
caoutchouc, and then be used as a receiver for containing
self-accendible gas over either water or mercury, the gas is
found to lose its spontaneous inflammability in a few minutes.
White fumes often appear in the gas at the same time ; but
these, I am satisfied, are due to the evolution of some gaseous
oxygen from the liquids, and only occur in the case of the
portion of gas which is first brought into contact with the li-
quid, and do not appear in the case of subsequent additions
of gas, although the liquid remains capable of destroying the
spontaneous accendibility of many portions of gas successively
exposed to it. It is not easy to decide whether these vapours
destroy irrecoverably the peculiar substance of spontaneous
inflammability, or merely negative the action of that principle
by their presence. I am inclined to think, however, that they
destroy that principle, for the action is not so rapid as the
diffusion of the vapour through the gas, the impregnation
appearing to be fully accomplished, and yet the loss of inflam-
mability not occurring sometimes for two or three minutes
afterwards ; particularly in the case of naphtha ; a portion of
that pure liquid in which potassium had been preserved be-
ing used in the experiment. A small addition of aether vapour
also destroys the inflammability of phosphuretted hydrogen,
although a distinct period must elapse before the change oc-
curs, such as a quarter of or half an hour. The action of alco-
hol vapour is much slower, generally requiring two or three
hours. Pure olefiant gas, containing no air, added in the
proportion of ten or twenty per cent., eventually destroys the
spontaneous inflammability, but requires a period of not less
than twenty or thirty hours. Olefiant gas has a negative in-
fluence of quite a different character, which has already been
alluded to, and which is in action the moment the gases are

Prof. Graham on Phosphuretted Hydrogen. 409

mixed, but which does not appear unless the proportion of
olefiant gas be very considerable. It is probable that aether
vapour and the gaseous hydro-carburets have an influence of
the same kind. An astonishingly minute quantity of an essen-
tial oil suffices to destroy the inflammability of the gas over
mercury, if allowed an hour or two to act. Hence it is very
difficult to preserve gas in the inflammable state in the mer-
curial trough, if any portion of the mercury has been soiled
by an essential oil.

7. The action of potassium on the peculiar principle is
equally remarkable. A most minute quantity of this metal or
of its amalgam destroys the self-accendibility of the gas in a
few minutes, without occasioning any reduction of volume
that could be measured. The fact is, that potassium or
its amalgam is without effect upon phosphuretted hydrogen
itself at the temperature of the air, neither absorbing nor de-
composing the gas ; but upon the peculiar principle, the action
of this metal is rapid and certain. One grain of potassium
amalgamated with fifty pounds of mercury rendered that
quantity of mercury quite unfit for retaining gas over it in an
inflammable condition for more than a few minutes. In such
experiments the interference of naphtha vapour was perfectly
excluded. Zinc and tin, either by themselves or in the state of
amalgam, have no sensible effect upon the self-accendible gas,
at least in a period of five or six hours. Protoxide of mer-
cury speedily withdraws the peculiar principle, but afterwards
also reacts slowly upon the gas itself. On the other hand,
the peroxide of the same metal is in no way injurious to the
self-accendible gas. Arsenious acid in powder acts in the
same manner as protoxide of mercury. The solution of
protosulphate of iron, if previously boiled, to deprive it of
air, is without effect upon the gas. The extraordinary action
of potassium, and that also, perhaps, of the essential oils,
seemed to point to the existence of an oxygenated principle
as the cause of the spontaneous inflammability of phosphu-
retted hydrogen. It is sufficiently evident that the propor-
tion in which this principle exists, to the whole gas, is ex-
ceedingly small, too minute to afford any hope of isolating
the principle. The nitrous impregnation, too, which was
found adequate to render gas spontaneously inflammable,
shows to how minute a quantity of matter the spontaneous
inflammability of phosphuretted hydrogen may, at times, be
owing. It seemed within the bounds of possibility that the
gas might owe its spontaneous inflammability in ordinary cir-
cumstances, if not to nitrous acid, at least to some other prin-
ciple allied to that substance. This led to a careful re-

Third Series. Vol. 5. No. 30. Dec. 1834. 3 G

410 Prof. Graham on Phosphuretted Hydrogen,

examination of the properties of phosphuretted hydrogen
made inflammable by means of nitrous acid; a subject of much
interest, as illustrating the effect of a most minute and almost
infinitesimal quantity of foreign matter in communicating
to a chemical body so striking a property as spontaneous in-
flammability. Independently of the light which it may throw
upon the constitution of ordinary phosphuretted hydrogen in
reference to that property.

8. Phosphuretted hydrogen which had lost all trace of
spontaneous inflammability by standiug a day or two over
water, or the gas from hydrated phosphorous acid, could be
impregnated with nitrous acid and made spontaneously in-
flammable in various ways. It was ascertained that the gas
obtained by either process was affected in the same way.
Such gas only, entirely destitute of spontaneous inflamma-
bility, was employed in the following experiments.

(1.) The nitrous acid of Dulong may be added directly to
the gas over mercury ; a glass spherule, or the bore of a short
piece of thermometer tube, being filled with the liquid, and
passed up to the gas. When nitric acid is brought into con-
tact in this manner with the gas, a violent action ensues, but
with nitrous acid the evolution of white fumes is very slight.
The nitrous acid is absorbed in part by the mercury, but this
absorption is slow, provided the quantity of gas with which
the acid vapour is mixed be considerable. If the quantity of
gas primarily impregnated with nitrous acid in the manner
described be small, or the impregnation of nitrous acid con-
siderable, the gas exhibits no disposition to smoke or to take
fire when passed into air. It has not become spontaneously
accendible. On diluting the gas with a large proportion of
unimpregnated phosphuretted hydrogen, no reaction is indi-
cated, but the whole becomes spontaneously inflammable in a
high degree. In fact, it was discovered that the gas is not
accendible when the nitrous acid exceeds a certain proportion,
which is by no means considerable.

(2.) Allow a single drop of nitrous acid to fall into a dry
glass jar, which may be of small dimensions : fill the jar with
mercury, and invert it, without loss of time, in the mercurial
trough. A bubble of gas will collect in the upper part of the
jar, which bubble is chiefly nitrous acid vapour. One cubic
inch or so, of phosphuretted hydrogen, or of hydrogen itself,
may then be added to the gas in the jar ; and this is our ni-
trous impregnating mixture : suppose this mixture to contain
one twentieth of its bulk of nitrous acid vapour ; the addition
of it in any proportion to phosphuretted hydrogen is not at-
tended by the slightest production of white fumes ; in fact, no

Prof. Graham on PhospJmretted Hydrogen. 411

reaction appears to take place. But the addition of a single
bubble of this mixture, not exceeding one tenth of an inch in
volume, to five or six cubic inches of phosphuretted hydrogen
will render the whole highly accendible, so that every bubble
passed into the air will take fire.

(3.) In the last arrangement a drop of the strongest nitric
acid may be substituted for the nitrous acid, in the prepara-
tion of the impregnating mixture. The nitric acid acts on
the mercury, and nitric oxide charged with nitrous acid va-
pour is collected, which may be diluted with hydrogen as
above.

The preceding processes uniformly afford a nitrous im-
pregnating mixture which may be depended upon ; but when
the experiment is attempted over water, there is not the same
certainty of the impregnation being successful. I have often,
however, made hydrogen highly suitable for the purpose, by
passing it through a column of fluid composed of nitric acid
recently diluted with water, provided that the acid had been
fuming from the presence of nitrous acid ; or by passing hy-
drogen through recently diluted sulphuric acid, as has already
been stated.

In regard to the proper proportion of nitrous acid vapour
to the phosphuretted hydrogen, I am satisfied that the pro-
portion most efficacious is somewhere between one part ni-
trous acid to one thousand, and one to ten thousand phos-
phuretted hydrogen. One nitrous acid to one hundred gas,
or less gas, is never accendible, but becomes so on diluting it
with enough of phosphuretted hydrogen.

I was anxious to discover how far nitric oxide interferes in
the phaenomena. The nitrous acid is never free from, but is
always accompanied with, a certain proportion of this gas.

9. Actionqf Nitric Oxide. — In atable formerly given (p. 405. ),
nitric oxide is set down as preventing the accendibility of the
good gas from phosphuret of lime, when the proportion of the
first is so great as one tenth of the whole mixture. In fact, the
best inflammable gas when mixed with nitric oxide in quan-
tity from two volumes to one tenth of a volume, exhibited no
symptom of spontaneous inflammability. The nitric oxide
forms red fumes when the mixture meets the air, but the
phosphuretted hydrogen does not even smoke; so that the
oxidation of the nitric oxide has not a kindling effect upon
the phosphuretted hydrogen, but the very reverse. A mix-
ture of one volume nitric oxide with twenty volumes of good
phosphuretted hydrogen (self-accendible per se) is still self-
accendible ; the bubble, however, does not take fire the instant
it bursts in the air, but after rising to a little height, and then

3 G2

412 Prof. Graham on Phosphuretted Hydrogen.

it explodes with a puff, like loose grains of gunpowder, and not
with the usual snap, the oxidation of the nitric oxide pre-
ceding by a sensible interval the oxidation of the phosphu-
retted hydrogen. Nitric oxide in a considerably smaller pro-
portion than g'jjth of a volume exhibits a sensible effect in re-
tarding the combustion of self-accendible gas, but does not al-
together prevent it.

In the case of phosphuretted hydrogen which was not self-
accendible, small additions of nitric oxide, such as one to one
hundred, to five hundred, to one thousand, or to two thousand
volumes phosphuretted hydrogen, did not induce self-accen-
dibility when the nitric oxide employed had been previously
washed with caustic alkali. The experiment was tried with
three different specimens of washed nitric oxide. But nitric
oxide which had not been washed with alkali, particularly if
it resulted from a turbulent action of the nitric acid on cop-
per, and came over charged with red fumes, and was withal
newly collected, was pretty often efficient in making the gas
self-accendible. The proper proportion of such nitric oxide
for this purpose was found to be one volume to a quantity
between those of one thousand and two thousand volumes of
phosphuretted hydrogen. A greater or a less proportion of
the nitric oxide failed to produce the desired effect. All these
experiments with nitric oxide were made over water.

It is well known that a mixture of phosphuretted hydrogen
and nitric oxide may be exploded by a bubble of oxygen gas,
a method of firing these gases first practised, I believe, by
Dr. Thomson. But Dr. Dalton found pure nitric oxide ca-
pable of oxygenating phosphuretted hydrogen in a gradual
manner when the two gases are left together, nitrous oxide
and nitrogen resulting. Possibly, therefore, it is by acting
itself upon phosphuretted hydrogen that nitric oxide pre-
vents atmospheric air from acting upon that gas in our expe-
riments. It is conceivable that the oxygenating action of ni-
tric oxide upon phosphuretted hydrogen may be promoted,
like that of air upon the same gas, by the presence of nitrous
acid, which will explain Dr. Thomsons experiment.

The impregnating nitrous mixture of the foregoing experi-
ments was not destitute of nitric oxide ; but what proves that
the efficiency of the mixture did not depend upon the last-men-
tioned ingredient is the circumstance that the mixture lost
its virtue by standing over mercury for a week, during which
period the acid vapour was absorbed by the mercury, but the
nitric oxide remained, as appeared on admitting air to the
gaseous mixture. Hence we may conclude, that when nitric
oxide acts in producing inflammability in phosphuretted hy-

Prof. Graham on Phosphuretted Hydrogen. 413

drogen, it is from the nitrous acid which it occasionally contains
It is certainly not a little curious that nitric oxide is not equi-
valent to nitrous acid in producing the change in question
upon phosphuretted hydrogen, seeing that the nitric oxide
passes immediately into nitrous acid upon meeting air.
Whether the negative influence of nitric oxide upon really
accendible gas is sufficient to account for this anomaly, I am
doubtful. It may be thought that nitrous acid and phosphu-
retted hydrogen when in contact for a short time, react upon
each other, with the production of some entirely new and
highly accendible body. But this supposition seems not to
quadrate with the fact that the impregnating mixture requires to
be diluted by so large a proportion of phosphuretted hydrogen
before the whole becomes spontaneously inflammable; nor
is it supported by any visible signs of reaction between the
nitrous acid and phosphuretted hydrogen. Indeed, nitrous acid
vapour appears to be compatible with phosphuretted hydrogen to
an extent which could not have been anticipated. Again, that
nitrous acid, or at least some acid compound of nitrogen, con-
tinues to exist in what we may now call nitrous phosphuretted
hydrogen gas, appears to be corroborated by the properties
which this self-accendible gas is found to possess.

10. Properties of Nitrous Phosphuretted Hydrogen. —
(1.) This gas loses its self-accendibility when kept over mer-
cury, in a period varying from six to twenty-four hours, ac-
cording to the amount of nitrous impregnation. It is re-
markable that this gas continues in general for a longer time
inflammable when confined over water than over mercury,
which is the reverse of what occurs with the gas from phos-
phuret of lime.

(2.) The factitious gas is deprived of its spontaneous inflam-
mability by charcoal and porous absorbents, by essential oils
and hydro-carburets, and by amalgam of potassium, and quite
as rapidly as is its natural prototype.

(3.) Phosphorous acid and concentrated sulphuric acid ap-
pear likewise to withdraw the nitrous principle, although
phosphoric acid does not. The agency of these acids pro-
bably exemplifies the disposition of nitrous acid to combine
with other acids. The action of potassium and of essential
oils upon nitrous acid requires no explanation. Potassium
has, I find, no action on pure nitric oxide in the cold.

(4.) A cubic inch of this gas, passed up into a receiver of
which the inside was moistened with caustic alkali, had its
accendibility sensibly impaired in fifteen minutes, but not
completely destroyed in less than an hour.

414 Prof. Graham on Phosphurelted Hydrogen,

In conclusion, the statement of the above properties is
abundantly sufficient to prove that a strong analogy subsists
between our nitrous phosphuretted hydrogen and the self-
accendible gas which has been so long in the hands of che-
mists. The peculiar principle of the last, therefore, may be
an oxygenated body. That principle cannot be nitrous acid,

but it may be a compound of phosphorus and oxygen (P)
analogous to nitrous acid. In all the reactions by which self-
accendible gas is produced, we have the simultaneous forma-
tion of compounds of phosphorus and oxygen, such as the hypo-
phosphorous and phosphoric acids. The compound P is
hypothetic, however, and has not been formed directly. Its
existence is only surmised from the parallelism which appears
to be established between nitrogen and phosphorus, and be-
tween their compounds; phosphuretted hydrogen itself corre-
sponding with ammonia, the phosphoric and phosphorous acids,
with the nitric and hyponitrous acids. The peroxide of chlorine

of Davy and Stadion (C) corresponds with nitrous acid and
with our hypothetic oxide of phosphorus, which we may speak
of as the peroxide of phosphorus. The peroxide of phosphorus
would appear to resemble the peroxide of chlorine in being
acted on more slowly by mercury and by alkalies than is the
case with nitrous acid. It is to be admitted, however, that
I did not succeed in producing an inflammable phosphuretted
hydrogen by the agency of peroxide of chlorine, — that there
is no chlorous phosphuretted hydrogen. The reason is, peroxide
of chlorine is incompatible with phosphuretted hydrogen, re-
acting upon that gas at the instant of mixture.

As to the mode in which nitrous acid vapour, in a propor-
tion so minute, contributes to the accendibility of phosphu-
retted hydrogen, I have been able to form no distinct idea.
The most likely conjecture is, that the nitrous acid, or re-
sulting hyponitrous acid, combines with some product of the
oxygenation of phosphuretted hydrogen, and thereby disposes
or promotes the occurrence of that change. The oxygena-
tion of pure hydrogen itself under the influence of a clean
plate of platinum, is not promoted in a sensible degree by any
nitrous impregnation. The sulphurous and muriatic acid
gases, and vapour of acetic acid, appeared to contribute no-
thing to the accendibility of phosphuretted hydrogen.

Summary. — It appears, then, that there are not two isomeric
phosphuretted hydrogens, but that the peculiarities of the gas
when spontaneously inflammable depend upon adventitious
matter :

Mr. Lyon's Observations on Magnetic Substances, 415

That some oxide of nitrogen, which in the present state of
our knowledge of that class of compounds seems to be the
nitrous acid, is capable of rendering phosphuretted hydrogen
spontaneously inflammable, when that oxide is present to the
extent of one ten-thousandth y art of the volume of the gas:

That such ga's has a general resemblance to phosphuretted
hydrogen as obtained in the spontaneously inflammable state
by ordinary processes, which last probably owes its ready ac-
cendibility to the presence of an equally minute trace of a
volatile compound of phosphorus and oxygen, analogous to
nitrous acid.

LVIII. Observations on Magnetic Substances. By Mr. David

Lyon.*

TRON was for a long space of time the only substance which
* was known to be capable of exhibiting magnetic pheno-
mena. It was afterwards found that two other metals, nickel
and cobalt, are endowed with a similar capacity.

Hence it appears that magnetism is not a peculiar essence
of one particular substance only; and that whatever be its na-
ture, it is not confined to one substance alone, but is common
to different chemical elements. It may, therefore, be properly
inquired, whether in any principal qualities, or in the numeri-
cal values of qualities, these elements do resemble one another,
and are likewise distinguishable from all the other elements.
For if such be the case, we may come to know on what mag-
netism depends, or in other words, to account for its presence
in these elements and in no other; although we do not enter
upon the question, as to what magnetism really is, or what is
its physical origin.

The atomic weights of the three magnetic elements, as stated
by Berzelius, are as follows :

Nickel 739-51

Cobalt 738-

Iron 678*43

The specific gravities, as stated in Pouillet's Elemens de
Physique, are,

Nickel 8-27

Cobalt 7'8

Iron 7*207

Thus, both in the atomic weights and in the specific gravities,
we observe that the three magnetic substances or elements
have values near together : and on inspecting the values of all
the chemical elements, we observe further, that there is no

* Communicated by the Author.

416 Mr. Lyon's Observations on Magnetic Substances.

other element whose values come very near or fall within
those of the three magnetic elements. This is a fact or ob-
servation which appears hitherto not to have been brought
forward, but which is certainly deserving of notice, both for
itself, and for the considerations to which it may lead.

If, for the several chemical elements, we divide the specific
gravities by the atomic weights respectively, we shall obtain
a series of numbers, which are the relative numbers of atoms
of the several elements contained in a given space or volume.
In this way, and making use of the values stated above, we
have for the three magnetic elements:

« .«. *t .. *. • Aur • u.l Atoms contained

Specific Gravity. Atomic Weights.
1 J & in a given space.

Nickel 8-27 ... 739*51 ... 1118

Iron 7*207 ... 678*43 ... 1062

Cobalt 7*8 ... 738* ... 10.57

It will scarcely need to be noted, with reference to this cal-
culation, that we are at liberty to remove the decimal points,
provided it be done uniformly for all.

On considering the two series, i. e. the atomic weights and
the ratios of atoms contained in a given space, respectively,
for the several chemical elements, we shall be conducted to
speculations relative to the atomic bulks ; or in other words,
to investigate what may be the relative bulks or sizes of the
solid nucleus of the atoms of the several elements. But for
our present purpose, still attending solely to the three mag-
netic elements, when we consider the approximation of their
numbers in these two series, there appears no ground for he-
sitation in allowing that their atomic bulks must be but little
different from one another.

We come then to the conclusion that the values of the
atomic weights, and likewise of the atomic bulks of the three
magnetic elements, are near together*. And we shall find
further, that no other element approaches them in both these

* The atomic weights stated above are those published by Berzelius in
his Essai sur la Thi'orie des Proportions Chimiques, and copied in the fifth
edition of Thenard's Traite de Chimie. In a subsequent list, published by
Berzelius in the Annates de Chimie et de Physique, tom.xxxviii. (1828), and
copied in Dr. Daubeny's Introduction to the Atomic Theory, some modifi-
cations are made in the atomic weights. The metals generally have num-
bers assigned to them, which are one half of those in the former list. But
they have not all been so reduced; there are exceptions in some few in-
stances. Now according to this later series, it is further remarkable, on
forming as above indicated a table of the numbers of atoms contained in a
given space, that of all the chemical elements, with the exception of car-
bon, the three magnetic elements and copper are those which have the
greatest numbers in that table.

Mr. Lyon's Observations on Magnetic Substances. 41,7

respects. And are not these two qualities the principal (if not
the only) primary qualities which belong to atoms, and may
be different in value for the different chemical elements?

May it not be hence inferred, that the power or liability
to manifest the magnetic phenomena, — being peculiar to, or
most observable in, certain elements, and them only, — is de-
pendent upon the values of those two qualities in their atoms ?
But what the particular nature may be of the connexion
binding the magnetic phaenomena to such elements as have
values of the two qualities at or near to the mean of the
values of the three elements, iron, nickel, and cobalt, may be
the subject of further research.

It will thus be observed that in inquiries into magnetism
we may distinguish two parts, independent of each other :
1st, the nature of the magnetic substance ; 2nd, the nature
of the magnetic phaenomena, or the real source of their pro-
duction, and the description of the minute and latent modes
of the phaenomena themselves. What has been adduced
above, relates solely to the former of these parts.

With regard to the latter, and chiefly for the sake of its
bearing upon the inference or view above proposed, it may
be well to state that I have been engaged in an investigation,
which appears to me to disclose the origin or fundamental
principle of the phaenomena of terrestrial magnetism. It may
be added that the original idea of this investigation occurred
to me, and was pursued some time previously to either of the
inquiries relative to magnetism. Not knowing, however,
whether my present communication will be permitted to ap-
pear in the pages of the Philosophical Magazine, and also on
account of the additional space, and the diagrams that would
be required for the development of my views on this subject,
the exposition of the same must be deferred for another com-
munication.

For the reason before mentioned, I still think it will be of
service to give a brief notice thereof, and have accordingly
drawn up the subjoined queries for that purpose.

Whether, in considering more rigorously the principles
applicable to the rotation of the globe, f. e. on examining more
minutely into the actual path of translation of the atoms, there
may not be found the origin or real source of production of
the phaenomena of terrestrial magnetism ; it being conceived
that this path is not represented in its ultimate form by the
theory which lays it down as being a circle.

And whether the discussion of this matter will not more im-
mediately (and previously to or apart from any discussion of
the agency of an aether, or of the consequences of the hetero-

Third Series. Vol. 5. No. 30. Dec. 1834. 3 H

418 Mr. Sturgeon's Description of

geneity of atoms in the globe,) afford the natural interpreta-
tion of the law or formula of the magnetic clip or inclination
deduced by Messrs. Biot and Kraft from data of observation,
viz. that for any given latitude, the tangent of the inclination
is to the tangent of that latitude as 2 : 1 .

If it can thus be shown that the fundamental principle of
terrestrial magnetism js necessarily connected with the path
of an atom, considered in a system homogeneously composed,
then with regard to the various chemical elements or species
of atoms composing the mass of the earth, the greater part
of which do not exhibit the magnetic phenomena, it would
remain to be examined in what manner, or by what circum-
stance, dependent upon the respective values of the two atomic
qualities before mentioned, the atomic paths of the greater
number are so far modified (from what may be called the
type, preserved in the magnetic elements,) as not to present
the (magnetic) phenomena in the same sensible way as the
three elements, iron, nickel, and cobalt.

In connexion with the foregoing investigations would come
another: whether, in general, the physical and chemical pro-
perties of the several chemical elements or species of atoms
may not depend upon the respective values of the atomic
weights and atomic bulks. And here it may be remarked
with respect to the magnetic elements, and the approximation
in their values of the two qualities, that besides the circum-
stance of their being magnetic, there are also to be observed
many marked analogies in their physical and chemical pro-
perties ; these analogies being, without doubt, greater than
what are to be found in the case of any two or more of the
other chemical elements.

Liverpool, April 22, 1834.

LIX. Description of a Thunder-Storm as observed at Wool-
wich; with some Observations relative to the Cause of the
Deflection of Electric Clouds by high Lands; and an Ac-
count of the Phenomena exhibited by means of a Kite ele-
vated during the Storm. By W. Sturgeon.*
CXN Saturday evening, (June 14th,) about 8 o'clock, an elec-
^^ trie storm passed partly over this place, exhibiting light-
ning the most splendid ever beheld. The wind was pretty brisk
from S. by W. about the first appearance of the storm, and
if the electric clouds had obeyed the force of the wind only,
the principal part of them would have come directly over us.
This, however, was not the case, for instead of their being
■ Communicated by the Author.

a Thunder-storm as observed at Woolwich. 419

carried over Woolwich in the direction of the wind, the most
formidable group of them, and consequently the greatest fury
of the storm, were deflected out of the wind's track before
their arrival at Shooter's Hill, and were carried over the low
lands on the other side of the hill, towards the Thames, in a
direction nearly from W.S.W. to E.N.E.

The deflection of electrized clouds out of the wind's direc-
tion, though, perhaps, not much noticed, is a very common
circumstance in the neighbourhood of high lands, especially
if those lands are composed of materials which are bad con-
ductors of electricity. For although they do not absolutely
refuse the transmission of the electric matter driven to the
surface of the hill from the lower strata of air* by the dis-
turbing force of the condensed electric fluid in the clouds,
the transfusion into the ground is too tardily performed to
prevent accumulation on the surface, which consequently be-
comes charged in the same state as the clouds that are ap-
proaching it. A reaction immediately takes place, and a con-

* The asperifolious plants, and the vegetable clothing of the land ge-
nerally, especially at this season of the year, receive the electric fluid from
the atmosphere in great abundance ; and the myriads of vegetable points,
sharp edges, &c, presented to the air, offer every facility for its reception
on any emergency of pressure emanating from the repulsive force of a
highly charged cloud. The surface of the land thus becomes charged at
the expense of the air, each gradually resuming its natural electric equili-
brium again, as the disturbing force withdraws its influence, by the pro-
gress of the cloud in its course. Thus new tracts of country become
charged in succession as the cloud approaches them, and an electrical tide
sweeps the face of the land by the floating influence above.

It is on this account that insulated kite-strings, exploring rods, &c, fre-
quently become negatively electric at the approach, and during the transit,
of clouds of this description. But if the kite or the exploring rod were
to reach into the cloud, it is not likely that either of them would ever be
found in a negative state. I am speaking of the principal influencing
cloud, and not of those straggling thin patches in their vicinity, which fre-
quently became negative by a portion of the electric matter which they
before possessed being driven out of them by the predominating electric
force of the superior cloud. In the same manner, an insulated metallic
rod furnished with fine points or sharp edges at its further extremity, may
have its natural electric fluid driven out of it into the air, by the approxi-
mation of a positively charged body at the other end.

I have never yet found the atmosphere negative with regard to the
earth at any other time than when modified by such causes as I have
pointed out. I have made upwards of four hundred electric kite experi-
ments, under almost every circumstance of weather, at various times of
the day and night, and in every season of the year; I have experimented
on Shooter's Hill, and on the low lands on the Woolwich and Welling
sides of it, and the experiments in the three different places within an
hour of each other; I have done the same on Chatham lines, and.in the
valley on the Chatham side of them ; on Norwood Hill, and in the plain at
Addiscombe; also on the top of the Monument in London, and during

3 H2

420 Mr. Sturgeon's Description of

sequent repulsion or deflection of the clouds is produced.
This electric force now operating in conjunction with the
wind, gives the cloud a new direction of motion, and urges it
over a tract of country composed of better conductors, which
are more susceptible of being transpierced by the electric
matter than those from which the cloud was deflected.
Hence it is that electric storms are more frequent and more
violent over marshy lands, rivers, &c, than over drier and
more elevated tracts of country*.

These causes operated in a very beautiful manner in giving
direction to the storm on Saturday evening. The principal
group of clouds, as before stated, never reached Shooter's
Hill, but was carried over the low wet lands, on the other
side, to the Thames ; and the foremost clouds were taken to
the other side of the river, and over a considerable tract of
the Essex marshes. At this period another direction was
given to the storm, and the new combination of forces urged
it in the direction of the river, a route which electric storms
visiting this neighbourhood very frequently take.

Its progress down the river was exceedingly slow, owing,
as I suppose, to the wind (though much slackened before this
time) being more directly opposed to it. I had been floating
an electric kite in the Artillery Barrack-field during the
transit of that part of the storm which passed over Woolwich.
I had got completely wet with the heavy rain which fell du-
ring the time ; notwithstanding which, the unusual fineness of
the lightning which was playing over the river and marshes
induced me to pursue it with my eye, when, from its distance,
I could no longer explore the theatre of its resplendent exhi-

the present year, on the top of some of the high hills in Westmoreland
and in the North Riding of Yorkshire ; and in every case I have found the
atmosphere positive with regard to the ground. In most of these cases,
the stations at the tops of the hills were higher than the place of the
kite when the experiments were made at the lower ones.

I have floated three kites at the same time, at very different altitudes,
and have uniformly found the highest to be positive to the other two, and
the centre kite positive to that which was below it; consequently the
lowest one was negative to the two above it ; but still it was positive to
the ground on which I was standing. I have made more than twenty ex-
periments of this kind, and the results (with the exception of electric ten-
sion) were invariably the same; showing most decidedly that the atmo-
sphere in its undisturbed electric state is more abundantly charged than
the earth, and, as far as I have been able to explore it, still more abund-
antly in the upper than in the lower strata.

* Immense tracts of flat country frequently become charged in the same
manner and from the same cause as ranges of hills are charged ; but the
repulsive force from such places is directed vertically, and not so directly
opposed to the horizontal direction of the cloud's motion as that pro.
ceeding from the side of a high hill.

a Thunder-storm as observed at Woolwich. 421

bition. I walked to the top of Wellington-street, from which
place I had an exceedingly fine view of the storm, now too
distant to hear even a feeble murmur of those thunders,
which, I am persuaded I may safely affirm, were to the in-
habitants immediately in their vicinity terrible to an unusual
degree.

It was now 9 o'clock, and the lightning was magnificent
indeed. Nature appeared as if disposed to gratify the utmost
extent of curiosity by an unremitting display of her electrical
elemental fire.

For about half an hour the storm appeared to be nearly
stationary, hovering over a tract of low land on the Essex
and Kent sides of the Thames, perhaps not far from Purfleet.
The lightning was unusually refulgent; the flashes in rapid
succession, and discharged in every possible direction that
can be imagined, and, generally through a longer striking
distance than I had ever before noticed. Three or four dis-
charges which occurred a little after 9 o'clock, darted through
a horizontal arch of about 50° each ; and several of those
which were directed vertically and oblique to the horizon,
shot through 30° or 40°, the fluid being visible in every part
of the circuit.

If this lightning was discharged over Purfleet, or there-
abouts, as I have supposed, it would be about eight miles
from where I was standing. Now allowing seven miles to be
the mean distance of the lightning discharged in a track at
right angles to the line of sight, the angle of 50° would
give a chord of nearly six miles and a half for the striking
distance, or the tract of air through which the lightning tra-
velled visibly at one discharge. The apparently vertical and
oblique discharges were much nearer in some part of the cir-
cuits than those which shot through the extraordinary hori-
zontal ranges. The rain, I imagine, was falling in torrents,
which would greatly facilitate the transmission through long
striking distances. Moreover, the inferior density of the air
in the regions of the clouds, and the thin aqueous vapours
which are floating there, tend very much to facilitate the trans-
mission.

Buildings, trees, and other tall objects are not usually
struck by lightning before the falling of rain, the dry dense
air offering too great a resistance to be transpierced from the
clouds to the ground.

From the time that the clouds arrived within the influence
of the Thames, they seemed to travel nearly in its direction ;
for although the lightning played over some miles of country
on both sides of its banks, the river appeared to be the direc-

422 Mr. Sturgeon's Description of

tion line to the focus of the storm, which, if not earlier dis-
posed of, would probably be transported by it to the Nore or
to the Channel ; a direction nearly at right angles to that of
the wind at this place.

The lightning was very fine from the straggling clouds
which passed over our heads, and from others which crossed
the Thames much nearer to London. These clouds separated
from the splendid group already noticed, and travelled in the
direction of the wind towards the N. or N. by E., and would,
if not obstructed, discharge their lightnings as a distinct storm
over the country about Waltham, Epping, Chipping Ongar,
Harlow, &c.

The wind had abated to such a degree before I arrived in
the Barrack-field, and the rain fell so heavily during the time
I was there, that it was with some difficulty that I got the kite
afloat; and when up, its greatest altitude, I imagine, did not
exceed fifty yards. The silken cord also, which had been
intended for the insulator, soon became so completely wet
that it was no insulator at all. Notwithstanding all these im-
pediments being in the way, I was much gratified with the
display of the electric matter issuing from the end of the
string to a wire, one end of which was laid on the ground,
and the other attached to the silk at about four inches distance
from the reel of the kite string. An uninterrupted play of
the fluid was seen over the four inches of wet silken cord, not
in sparks, but in a bundle of quivering purple ramifications,
producing a noise similar to that produced by springing a
watchman's rattle. Very large sparks, however, were fre-
quently seen between the lower end of the wire (which rested
on the grass) and the ground ; and several parts of the string
towards the kite, where the wire was broken, were occa-
sionally beautifully illuminated. The noise from the string
in the air was like to the hissing of an immense flock of geese,
with an occasional rattling or scraping sort of noise.

Two non-commissioned officers of the Royal Artillery were
standing by me the whole of the time, who, unaware of the
consequence, would very gladly have approached close to the
string; and it was not until I had convinced them of the
danger of touching, or even coming near to it, at a time when
the lightning was playing about us in every direction, that
I could dissuade them from gratifying their curiosity too far;
probably at the expense of their lives. We anxiously and
stedfastly watched what was going on at the end of the string,
and the display was beautiful beyond description. The reel
was occasionally enveloped in a blaze of purple arborized
electrical fire, whose numberless branches ramified over the

a Thunder-storm as observed at Woolwich, 423

silken cord, and through the air to the blades of grass, which
also became luminous, on their points and edges, over a sur-
face of some yards in circumference. We also saw a com-
plete globe of fire pass over the silken cord between the wire
and reel of the kite-string. The soldiers thought it about the
size of a musket-ball. It was exceedingly brilliant, and was
the only one that we noticed.

I had no electrometer with me, nor any of the apparatus
with which J perform chemical and magnetical experiments
by atmospheric electricity; hence the whole of the time on
this occasion was devoted to mere observation.

The following is a notice, extracted from the Lancaster Ga-
zette of the 5th of April last, of some experiments made with
an electrical kite at Kirkby Lonsdale, in Westmoreland : —

On Saturday the 29th of March, I had a very favourable
opportunity of demonstrating experimentally to several of
my friends at Kirkby Lonsdale, who had attended my recent
course of lectures at that place, that an abundance of the elec-
tric fluid usually attends hail and snow storms. The wind
was pretty brisk, cold, and from the W. by N. nearly the
whole of the day. There were several hail showers, each of
which, with a simultaneous increase of wind, became a com-
plete transient storm.

During three of these hail-storms, I floated one of my
silken electric kites, with a wired string of about 300 yards long,
and insulated in the usual way by means of a silken cord.

The kite was elevated in each experiment about ten mi-
nutes prior to the arrival of the hail-storm ; and the electric
state of the atmosphere ascertained, which was found to be so
exceedingly feeble that not the slightest spark could be ob-
served. As, however, the cloud from which the hail was fall-
ing approached the kite, the fluid from the string presented
itself in brilliant sparks to the knuckle; and during the transit
of the cloud, became so abundantly discharged to a wire pre-
sented to the string, that it struck in rapid succession through
a stratum of six inches of air; and through three inches of
air, it presented a splendid continuous stream of electric fire.
As the cloud receded from the kite, by advancing in its aerial
course, the electric discharges became less and less brilliant,
and continued to diminish in splendour and energy with the
recession of the passing storm, ultimately vanishing altogether
by the emergence of the kite from the electric influence of the
cloud.

These appearances were exhibited in each experiment, but
the display of the electric fire was the most magnificent in the

424* Dr. Faraday's Experimental Researches in Electricity.

second, which was during the fiercest hail-storm of that day,
and happened between two and three in the afternoon. Du-
ring an early part of this storm the electric fluid made a con-
tinuous rattling noise down the kite-string (in consequence of
the wire being broken in several places), and darted from the
reel, at the inferior extremity, to greater distances than in
either of the other experiments. In one instance it struck
over a stick about a yard long, to the hand of a young man
named Croft, who was presenting it to the kite-string. Al-
though the remote end of the stick was in connexion with the
ground by means of a very wet string, and consequently a con-
siderable discharge must, at the same time, have passed down
the wet string to the earth, the shock was so violent as to
make Mr. Croft reel and nearly fall ; and I have some rea-
son to suppose that it has left an impression on his memory
which time will not speedily obliterate. The kite-strings,
however, broke very soon afterwards, and consequently the
experiments, on that occasion, terminated very abruptly, and
unfortunately at a time also when the fire was streaming from
the string in the greatest abundance, and with a degree of
splendour better imagined than described.

During the third time that the kite was afloat, about two
hours after the former, several gentlemen present experienced
smart electric shocks direct from the kite-string.

Artillery Place, Woolwich, June 16, 1834.

LX. Experimental Researches in Electricity. — Seventh Series*
By Michael Faraday, D.C.L. F.R.S. Fullerian Prof.
Chem. Royal Institution ; Corr. Memb. Royal and Imp .Acad d.
of Sciences, Paris, Peter sburgh, Florence, Copenhagen, Ber-
lin, Sfc.

[Continued from p. 344, and concluded.]

822. r ■''HE doctrine of definite electro-chemical action just
A laid down, and, I believe, established, leads to some
new views of the relations and classifications of bodies asso-
ciated with or subject to this action. Some of these I shall
proceed to consider.

823. In the first place, compound bodies may be separated
into two great classes, namely, those which are decomposable
by the electric current, and those which are not. Of the
latter, some are conductors, others non-conductors, of voltaic
electricity*. The former do not depend for their decom-

• 1 mean here by voltaic electricity, merely electricity from a most
abundant source, but having very small intensity.

General Principles of Definite Electrolytic Action. 425

posability, upon the nature of their elements only; for, of the
same two elements, bodies may be formed, of which one shall
belong to one class and another to the other class ; but pro-
bably on the proportions also (697.)- It is further remark-
able, that with very few, if any, exceptions (414*. 691.), these
decomposable bodies are exactly those governed by the re-
markable law of conduction I have before described (394.) ;
for that law does not extend to the many compound fusible
substances that are excluded from this class. I propose to
call bodies of this, the decomposable class, Electrolytes (664.)-

824. Then, again, the substances into which these divide,
under the influence of the electric current, form an exceed-
ingly important general class. They are combining bodies;
are directly associated with the fundamental parts of the doc*
trine of chemical affinity; and have each a definite proportion,
in which they are always evolved during electrolytic action.
I have proposed to call these bodies generally ions, or parti-
cularly anions and cations, according as they appear at the
anode or cathode (665.); and the numbers representing the
proportions in which they are evolved electro-chemical equiva*
lents. Thus hydrogen, oxygen, chlorine, iodine, lead, tin,
are ions ; the three former are anions, the two metals are cat-
ions, and 1, 8, 36, 125, 104, 58, are their electro-chemical
equivalents nearly.

825. A summary of certain points already ascertained re-
specting electrolytes, ions, and electro-chemical equivalents, may
be given in the following general form of propositions, with-
out, I hope, including any serious error.

826. i. A single ion, i. e. one not in combination with an-
other, will have no tendency to pass to either of the elec-
trodes, and will be perfectly indifferent to the passing current,
unless it be itself a compound of more elementary ions, and
so subject to actual decomposition. Upon this fact is founded
much of the proof adduced in favour of the new theory of
electro-chemical decomposition, which I put forth in a former
series of these Researches (518. &c).

827. ii. If one ion be combined in right proportions (697.)
with another strongly opposed to it in its ordinary chemical
relations, i. e. if an anion be combined with a cation, then
both will travel, the one to the anode, the other to the cathode,
of the decomposing body (530. 542.547.).

828. iii. It', therefore, an ion pass towards one of the elec-
trodes, another ion must also be passing simultaneously to the

* For references to the places in which the subjects of the several pre-
ceding series are noticed in our Magazine, see the number for September
last, present vol., pp. 161, 162, 165, 172. Edit.

Third Series. Vol.5. No. 30. Dec. 1834. 3 I

426 Dr. Faraday's Experimental Researches in Electricity.

other electrode, although, from secondary action, it may not
make its appearance (7*3.).

829. iv. A body decomposable directly by the electric cur-
rent, i. e. an electrolyte, must consist of two ions, and must also
render them up during the act of decomposition.

830. v. There is but one electrolyte composed of the same
two elementary ions; at least such appears to be the fact (697.),
dependent upon a law, that only single electro-chemical equiva-
lents of elementary ions can go to the electrodes, and not multiples.

831. vi. A body not decomposable when alone, as boracic
acid, is not directly decomposable by the electric current
when in combination (780.). It may act as an ion, going
wholly to the anode or cathode, but does not yield up its ele-
ments, except occasionally by a secondary action. Perhaps it
is superfluous for me to point out that this proposition has no
relation to such cases as that of water, which, by the presence
of other bodies, is rendered a better conductor of electricity,
and therefore is more freely decomposed.

832. vii. The nature of the substance of which the electrode
is formed, provided it be a conductor, causes no difference
in the electro-decomposition, either in kind or degree (807.
813.); but it seriously influences, by secondary action (744.),
the state in which the ions finally appear. Advantage may be
taken of this principle in combining and collecting such ions
as, if evolved in their free state, would be unmanageable*.

833. viii. A substance which, being used as the electrode,
can combine altogether with the ion evolved against it, is also,
1 believe, an ion, and combines, in such cases, in the quantity
represented by its electro-chemical equivalent. All the experi-
ments I have made agree with this view ; and it seems to me,
at present to result as a necessary consequence. Whether,
in the secondary actions that take place where the ion acts,
not upon the matter of the electrode, but on that which is
around it in the liquid (744.), the same consequence follows,
will require more extended investigation to determine.

834. ix. Compound ions are not necessarily composed of
electro-chemical equivalents of simple ions. For instance,
sulphuric acid, boracic acid, phosphoric acid, are ions, but
not electrolytes, i. e. not composed of electro-chemical equiva-
lents of simple ions.

* It will often happen that the electrodes used may be of such a nature
as, with the fluid in which they are immersed, to produce an electric cur-
rent, either according with or opposing that of the voltaic arrangement
used, and in this way, or by direct chemical action, may sadly disturb the
results. Still, in the midst of all these confusing effects, the electric cur-
rent, which actually passes in any direction through the decomposing body,
will produce its own definite electrolytic action.

Determination of Electro-chemical Equivalents. 427

835. x. Electro-chemical equivalents are always consistent,
i. e. the same number which represents the equivalent of a sub-
stance A when it is separating from a substance B, will also
represent A when separating from a third substance C.
Thus, 8 is the electro-chemical equivalent of oxygen, whether
separating from hydrogen, or tin, or lead; and 103*5 is the
electro-chemical equivalent of lead, whether separating from
oxygen, or chlorine, or iodine.

836. xi. Electro-chemical equivalents coincide, and are the
same, with ordinary chemical equivalents.

837. By means of experiment and the preceding proposi-
tions, a knowledge of ions and their electro-chemical equiva-
lents may be obtained in various ways.

838. In the first place, they may be determined directly, as
has been done with hydrogen, oxygen, lead, and tin, in the
numerous experiments already quoted.

839. In the next place, from propositions ii. and iii. may
be deduced the knowledge of many other ions, and also their
equivalents. When chloride of lead was decomposed, platina
being used for both electrodes (395.), there could remain no
more doubt that chlorine was passing to the anode, although
it combined with the platina there, than when the positive
electrode, being of plumbago (794.), allowed its evolution in
the free state ; neither could there, in either case, remain any
doubt, that for every 103*5 parts of lead evolved at the
cathode, 36 parts of chlorine were evolved at the anode, for
the remaining chloride of lead was unchanged. So also when
in a metallic solution one volume of oxygen, or a secondary
compound containing that proportion, appeared at the anode,
no doubt could arise that hydrogen, equivalent to two vo-
lumes, had been determined to the cathode, although, by a'
secondary action, it had been employed in reducing oxides of
lead, copper, or other metals, to the metallic state. In this
manner, then, we learn from the experiments already de-
scribed in these Researches, that chlorine, iodine, bromine,
fluorine, calcium, potassium, strontium, magnesium, manga-
nese, &c, are ions, and that their electro-chemical equivalents
are the same as their ordinary chemical equivalents.

840. Propositions iv. and v. extend our means of gaining
information. For if a body of known chemical composition
is found to be decomposable, and the nature of the substance
evolved as a primary or even a secondary result (743. 777.)
atone of the electrodes, be ascertained, the electro-chemical
equivalent of that body may be deduced from the known con-
stant composition of the substance evolved. Thus, when
fused protiodide of tin is decomposed by the voltaic current

3 12

428 Dr. Faraday's Experimental Researches in Electricity.

(804.), the conclusion may be drawn, that both the iodine and
tin are ions, and that the proportions in which they combine
in the fused compound express their electro-chemical equiva-
lents. Again, with respect to the fused iodide of potassium
(805.), it is an electrolyte; and the chemical equivalents will
also be the electro-chemical equivalents.

841. If proposition viii. sustain extensive experimental in-
vestigation, then it will not only help to confirm the results
obtained by the use of the other propositions, but will give
abundant original information of its own.

842. In many instances, the secondary results obtained by
the action of the 'evolving ion on the substances present in
the surrounding liquid or solution, will give the electro-che-
mical equivalent. Thus, in the solution of acetate of lead,
and, as far as I have gone, in other proto-salts subjected to
the reducing action of the nascent hydrogen at the cathode,
the metal precipitated has been in the same quantity as if it
had been a primary product, (provided no free hydrogen
escaped there,) and therefore gave as accurately the number
representing its electro-chemical equivalent.

843. Upon this principle it is that secondary results may
occasionally be used as measurers of the volta-electric current
(706. 740.) ; but there are not many metallic solutions that
answer this purpose well; for unless the metal is easily pre-
cipitated, hydrogen will be evolved at the cathode and vitiate
the result. If a soluble peroxide is formed at the anode, or
if the precipitated metal crystallize across the solution and
touch the positive electrode, similar vitiated results are ob-
tained. I expect to find in some vegetable salts, as the
acetates of mercury and zinc, solutions favourable for this use.

844. After the first experimental investigations to establish
the definite chemical action of electricity, 1 have not hesitated
to apply the more strict results of chemical analysis to correct
the numbers obtained as electrolytical results. This, it is
evident, may be done in a great number of cases, without
using too much liberty towards the due severity of scientific
research. The series of numbers representing electro-che-
mical equivalents must, like those expressing the ordinary
equivalents of chemically acting bodies, remain subject to the
continual correction of experiment and sound reasoning.

845. I give the following brief Table of ions and their
electro-chemical equivalents, rather as a specimen of a first
attempt than as anything that can supply the want, which
must very quickly be felt, of a full and complete tabular ac-
count of this class of bodies. Looking forward to such a table
as of extreme utility (if well constructed) in developing the

•Anions, Cations, and Electro-chemical Equivalents, 429

intimate relation of ordinary chemical affinity to electrical ac*
tions, and identifying the two, not to the imagination merely,
but to the conviction of' the senses and a sound judgement,
I may be allowed to express a hope, that the endeavour will
always be to make it a table of real, and not hypothetical,
electro-chemical equivalents; for we shall else overrun the
facts, and lose all sight and consciousness of the knowledge
lying directly in our path.

846. The equivalent numbers do not profess to be exact,
and are taken almost entirely from the chemical results of
other philosophers in whom I could repose more confidence,
as to these points, than in myself.

847. Table of Ions.
Anions.

Oxygen 8

Chlorine 355

Iodine 126

Bromine 783

Fluorine 187

Cyanogen 26

Sulphuric acid... 40

Hydrogen 1

Potassium 39-2

Sodium 23-3

Lithium 10

Barium 68*7

Strontium 43*8

Calcium 20-5

Magnesium 12-7

Manganese .... 27*7

Zinc 32-5

Tin 57-9

Lead 103-5

Iron 28

Selenic acid 64

Nitric acid 54

Chloric acid 75*5

Phosphoric acid 35-7

Carbonic acid... 22

Boracic acid 24

Acetic acid 51

Cations.

Copper 31-6

Cadmium 55-8

Cerium 46

Cobalt 2.9-5

Nickel 29-5

Antimony 64-6?

Bismuth 71

Mercury 200

Silver 108

Platina 98'6?

Gold (?)

Tartaric acid 66

Citric acid 58

Oxalic acid 36

Sulphur (?) 16

Selenium (?) ....
Sulpho-cyanogen

Ammonia 17

Potassa 47-2

Soda 31-3

Lithia 18

Baryta 76-7

Strontia 51-8

Lime 28*5

Magnesia 20-7

Alumina (?)

Protoxides generally.

Quinia 171*6

Cinchona 160

Morphia 290

Vegeto-alkalies generally.

848. This Table might be further arranged into groups of
such substances as either act with, or replace, each other.
Thus, for instance, acids and bases act in relation to each
other; but they do not act in association with oxygen, hydro-
gen, or elementary substances. There is indeed little or no
doubt that, when the electrical relations of the particles of
matter come to be closely examined, this division must be
made. The simple substances, with cyanogen, sulpho-cyano-
gen, and one or two other compound bodies, will probably
form the first group; and the acids and bases, with such
analogous compounds as may prove to be ions, the second
group. Whether these will include all ions, or whether a

430 Dr. Faraday's Experimental Researches in Electricity,

third class of more complicated results will be required, must
be decided by future experiments.

84-9. It is probable that all our present elementary bodies
are ions, but that is not as yet certain. There are some, such
as carbon, phosphorus, nitrogen, silicon, boron, alumium, the
right of which to the title of ion it is desirable to decide as
soon as possible. There are also many compound bodies,
and amongst them alumina and silica, which it is desirable to
class immediately by unexceptionable experiments. It is also
possible, that all combinable bodies, compound as well as sim-
ple, may enter into the class of ions ; but at present it does not
seem to me probable. Still the experimental evidence I have
is so small in proportion to what must gradually accumulate
around, and bear upon, this point, that I am afraid to give a
strong opinion upon it.

850. I think I cannot deceive myself in considering the
doctrine of definite electro-chemical action as of the utmost im-
portance. It touches by its facts more directly and closely than
any former fact, or set of facts, have done upon the beautiful
idea, that ordinary chemical affinity is a mere consequence
of the electrical attractions of the particles of different kinds
of matter ; and it will probably lead us to the means by which
we may enlighten that which is at present so obscure, and
either fully demonstrate the truth of the idea, or develop that
which ought to replace it.

851. A very valuable use of electro-chemical equivalents
will be to decide, in cases of doubt, what is the true chemical
equivalent, or definite proportional, or atomic number of a
body ; for I have such conviction that the power which go-
verns electro-decomposition and ordinary chemical attractions
is the same ; and such confidence in the overruling influence
of those natural laws which render the former definite, as to
feel no hesitation in believing that the latter must submit to
them also. Such being the case, I can have no doubt that,
assuming hydrogen as 1, and dismissing small fractions for the
simplicity of expression, the equivalent number or atomic
weight of oxygen is 8, of chlorine 36, of bromine 78*4<, of lead
103*5, of tin 59, &c, notwithstanding that a very high au-
thority doubles several of these numbers.

§ 13. On the absolute Quantity of Electricity associated with
the Particles or Atoms of Matter.

852. The theory of definite electrolytical or electro-chemi-
cal action appears to me to touch immediately upon the abso-
lute quantity of electricity or electric power belonging to dif-
ferent bodies. It is impossible, perhaps, to speak on this point

Absolute Quantity of Electricity in Matter. 431

without committing oneself beyond what present facts will
sustain ; and yet it is equally impossible, and perhaps would
be impolitic, not to reason upon the subject. Although we
know nothing of what an atom is, yet we cannot resist forming
some idea of a small particle, which represents it to the mind ;
and though we are in equal, if not greater, ignorance of elec-
tricity, so as to be unable to say whether it is a particular
matter or matters, or mere motion of ordinary matter, or
some third kind of power or agent, yet there is an immensity
of facts which justify us in believing that the atoms of matter
are in some way endowed or associated with electrical powers,
to which they owe their most striking qualities, and amongst
them their mutual chemical affinity. As soon as we perceive,
through the teaching of Dalton, that chemical powers are,
however varied the circumstances in which they are exerted,
definite for each body, we learn to estimate the relative de-
gree of force which resides in such bodies : and when upon
that knowledge comes the fact, that the electricity, which we
appear to be capable of loosening from its habitation for a
while, and conveying from place to place, whilst it retains its
chemical force, can be measured out, and, being so measured,
is found to be as definite in its action as any of those portions
which, remaining associated with the particles of matter, give
them their chemical relation-, we seem to have found the link
which connects the proportion of that we have evolved to the
proportion of that belonging to the particles in their natural
state.

853. Now it is wonderful to observe how small a quantity
of a compound body is decomposed by a certain portion of
electricity. Let us, for instance, consider this and a few other
points in relation to water. One grain of water acidulated to
facilitate conduction, will require an electric current to be
continued for three minutes and three quarters of time to
effect its decomposition, which current must be powerful
enough to retain a platina wire T^ of an inch in thickness*,
red hot, in the air, during the whole time; and if interrupted
anywhere by charcoal points, will produce a very brilliant and
constant star of light. If attention be paid to the instan-
taneous discharge of electricity of tension, as illustrated in

* I have not stated the length of wire used, because I find by experi-
ment, as would be expected^ in theory, that it is indifferent. The same
quantity of electricity which, passed in a given time, can heat an inch of
platina wire of a certain diameter red hot, can also heat a hundred, a
thousand, or any length of the same wire to the same degree, provided the
cooling circumstances are the same for every part in both cases. This I
have proved by the volta-clectrometer. I found that whether half an inch

432 Dr. Faraday's Experimental Resea?rkes in Electricity.

the beautiful experiments of Mr. Wheatstone *, and to what
I have said elsewhere on the relation of common and voltaic
electricity (371. 375. ), it will not be too much to say, that this
necessary quantity of electricity is equal to a very powerful
flash of lightning. Yet we have it under perfect command;
can evolve, direct, and employ it at pleasure; and when it has
performed its full work of electrolyzation, it has only separated
the elements of a single grain of water.

854. On the other hand, the relation between the conduc-
tion of the electricity and the decomposition of the water is so
close, that one cannot take place without the other. If the
water is altered only in that small degree which consists in its
having the solid instead of the fluid state, the conduction is
stopped, and the decomposition is stopped with it. Whether
the conduction be considered as depending upon the decom-
position, or not (413. 703.), still the relation of the two func-
tions is equally intimate and inseparable.

855. Considering this close and twofold relation, namely,
that without decomposition transmission of electricity does not
occur; and, that for a given definite quantity of electricity
passed, an equally definite and constant quantity of water
or other matter is decomposed; considering also that the
agent, which is electricity, is simply employed in overcom-
ing electrical powers in the body subjected to its action;
it seems a probable, and almost a natural consequence, that
the quantity which passes is the equivalent of, and therefore
equal to, that of the particles separated ; i. e. that if the elec-
trical power which holds the elements of a grain of water in
combination, or which makes a grain of oxygen and hydro-
gen in the right proportions unite into water when they are
made to combine, could be thrown into the condition of a cur-
rent^ it would exactly equal the current required for the sepa-
ration of that grain of water into its elements again.

856. This view of the subject gives an almost overwhelming
idea of the extraordinary quantity or degree of electric power
which naturally belongs to the particles of matter; but it is
not inconsistent in the slightest degree with the facts which

or eight inches were retained at one constant temperature of dull redness,
equal quantities of water were decomposed in equal times in both cases.
When the half-inch was used, only the centre portion of wire was ignited.
A fine wire may even be used as a rough but ready regulator of a voltaic
current; for if it be made part of the circuit, and the larger wires commu-
nicating with it be shifted nearer to or further apart, so as to keep the
portion of wire in the circuit sensibly at the same temperature, the current
passing through it will be nearly uniform.

* Literary Gazette, 1833, March 1 and 8. Philosophical Magazine, 1833,
p. 204. L*Irutitutt\&M, p. 261.

Absolute Quantity of Electricity in Matter. 433

can be brought to bear on this point. To illustrate this I must
say a few words on the voltaic pile *.

857. Intending hereafter to apply the results given in this
and the preceding series of Researches to a close investigation
of the source of electricity in the voltaic instrument, I have
refrained from forming any decided opinion on the subject ;
and without at all meaning to dismiss metallic contact, or the
contact of dissimilar substances, being conductors, but not
metallic, as if they had nothing to do with the origin of the
current, I still am fully of opinion with Davy, that it is at
least continued by chemical action, and that the supply con-
stituting the current is almost entirely from that source.

858. Those bodies which, being interposed between the
metals of the voltaic pile, render it active, are. all of them elec-
trolytes (476.) ; and it cannot but press upon the attention of
every one engaged in considering this subject, that in those
bodies (so essential to the pile) decomposition and the trans-
mission of a current are so intimately connected, that one
cannot happen without the other. This I have shown abund-
antly in water, and numerous other cases (402. 476.). If,
then, a voltaic trough have its extremities connected by a de-
composing body, as water, we shall have a continuous current
through the apparatus; and whilst it remains in this state
may look at the part where the acid is acting upon the plates,
and that where the current is acting upon the water, as the
reciprocals of each other. In both parts we have the two
conditions inseparable in such bodies as these, namely, the
passing of a current, and decomposition ; and this is as true
of the cells in the battery as of the water cell ; for no voltaic
battery has as yet been constructed in which the chemical
action is only that of combination ; decomposition is always
included, and is, I believe, an essential chemical part.

859. But the difference in the two parts of the connected
battery, that is, the decomposing or experimental cell, and
the acting cells, is simply this. In the former we urge the
current through, but it, apparently of necessity, is accom-
panied by decomposition : in the latter we cause decomposi-
tions by ordinary chemical actions, (which are, however,
themselves electrical,) and, as a consequence, have the electri-
cal current ; and as the decomposition dependent upon the cur-

* By the term voltaic pile, I mean such apparatus or arrangement of
metals as up to this time have been called so, and which contain water,
brine, acids, or other aqueous solutions or decomposable substances (476.),
between their plates. Other kinds of electric apparatus may be hereafter
invented, and I hope to construct some not belonging to the class of in-
struments discovered by Volta.

Third Series. Vol. 5. No. SO. Dec. 1834. 3 K

4S4« Dr. Faraday's Experimental Researches in Electricity.

rent is definite in the former case, so is the current associated
with the decomposition also definite in the latter (862. &c).

860. Let us apply this in support of what I have surmised
respecting the enormous electric power of each particle or
atom of matter (856.). I showed in a former series of these
Researches on the relation by measure of common and voltaic
electricity, that two wires, one of platina and one of zinc,
each one eighteenth of an inch in diameter, placed five six-
teenths of an inch apart, and immersed to the depth of five
eighths of an inch in acid, consisting of one drop of oil of
vitriol and four ounces of distilled water at a temperature of
about 60° Fahr., and connected at the other extremities by a
copper wire eighteen feet long, and one eighteenth of an inch
in thickness, yielded as much electricity in little more than
three seconds of time as a Leyden battery charged by thirty
turns of a very large and powerful plate electric machine in full
action (371. )• This quantity, though sufficient if passed at
once through the head of a rat or a cat to have killed it, as
by a flash of lightning, was evolved by the mutual action of
so small a portion of the zinc wire and water in contact with
it, that the loss of weight sustained by either would be inap-
preciable by our most delicate instruments ; and as to the
water which could be decomposed by that current, it must
have been insensible in quantity, for no trace of hydrogen
appeared upon the surface of the platina during those three
seconds.

861. What an enormous quantity of electricity, therefore,
is required for the decomposition of a single grain of water !
We have already seen that it must be in quantity sufficient to
sustain a platina wire T^¥ of an inch in thickness, red hot,
in contact with the air for three minutes and three quarters
(853.), a quantity which is almost infinitely greater than that
which could be evolved by the little standard voltaic arrange-
ment to which 1 have just referred (860. 371.). I have en-
deavoured to make a comparison by the loss of weight of such
a wire in a given time in such an acid, according to a prin-
ciple and experiment to be almost immediately described
(862.) ; but the proportion is so high, that I am almost afraid
to mention it. It would appear that 800,000 such charges of
the Leyden battery as I have referred to above, would be
necessary to supply electricity sufficient to decompose a single
grain of water; or, if I am right, to equal the quantity of elec-
tricity which is naturally associated with the elements of that
grain of water, endowing them with their mutual chemical
affinity.

862. In further proof of this high electric condition of the

Absolute Quantity of Electricity in Matter, 435

particles of matter, and the identity as to quantity, of that be-
longing to them with that necessary for their separation, I will
describe an experiment of great simplicity but extreme beauty,
when viewed in relation to the evolution of an electric current
and its decomposing powers.

863. A dilute sulphuric acid, made by adding about one
part by measure of oil of vitriol to thirty parts of water, will
act energetically upon a piece of plate zinc in its ordinary and
simple state; but, as Mr. Sturgeon has shown*, not at all, or
scarcely so, if the surface of the metal has in the first instance
been amalgamated ; yet the amalgamated zinc will act power-
fully with platina as an electromotor, hydrogen being evolved
on the surface of the latter metal, as the zinc is oxidized and
dissolved. The amalgamation is best effected by sprinkling
a few drops of mercury upon the surface of the zinc, the latter
being moistened with the dilute acid, and rubbing with the
fingers so as to extend the liquid metal over the whole of the
surface. Any mercury in excess forming liquid drops upon
the zinc, should be wiped offf.

864. Two plates of zinc thus amalgamated were dried and
accurately weighed; one, which we will call A, weighed 163*1
grains; the other, to be called B, weighed 148*5 grains. They
were about five inches long, and 0'4 of an inch wide. An
earthenware pneumatic trough was filled with dilute sulphuric
acid, of the strength just described (863.), and a gas jar, also
filled with the acid, inverted in it j. A plate of platina of
nearly the same length, but about three times as wide as the
zinc plates, was put up into this jar. The zinc plate A was
also introduced into the jar, and brought in contact with the
platina, and at the same moment the plate B was put into the
acid of the trough, but out of contact with other metallic
matter.

865. Strong action immediately occurred in the jar upon
the contact of the zinc and platina plates. Hydrogen gas
rose from the platina, and was collected in the jar, but no hy-
drogen or other gas rose from either zinc plate. In about ten
or twelve minutes, sufficient hydrogen having been collected,
the experiment was stopped ; during its progress a few small

* Recent Experimental Researches, &c, 1830, p. 74, &c.

■j- The experiment may be made with pure zinc, which, as chemists well
know, is but slightly acted upon by dilute sulphuric acid in comparison
with ordinary zinc, wbich during the action is subject to an infinity of vol-
taic actions. See De la Rive on this subject, Bibliotheque Universel/c,
1830, p. 391.

X The acid was left during a night with a small piece of unamalgamated
zinc in it, for the purpose of evolving such air as might be inclined to se-
parate, and bringing the whole into a constant state.

3K2

436 Dr. Faraday's Experimental Researches in Electricity.

bubbles had appeared upon the plate B, but none upon plate A.
The plates were washed in distilled water, dried, and re-
weighed. Plate B weighed 1 4-8*3 grains, as before, having
lost nothing by the direct chemical action of the acid. Plate A
weighed 1 54*65 grains, 8*45 grains of it having been oxidized
and dissolved during the experiment.

866. The hydrogen gas was next transferred to a water-
trough and measured; it amounted to 12*5 cubic inches, the
temperature being 52°, and the barometer 29*2 inches. This
quantity, corrected for temperature, pressure, and moisture,
becomes 12*15453 cubic inches of dry hydrogen at mean tem-
perature and pressure : which, increased by one half for the
oxygen that must have gone to the anode, i. e. to the zinc,
gives 18-232 cubic inches as the quantity of oxygen and hy-
drogen evolved from the water decomposed by the electric
current. According to the estimate of the weight of the
mixed gas before adopted (791.), this volume is equal to
2*3535544 grains, which therefore is the weight of water de-
composed ; and this quantity is to 8*45, the quantity of zinc
oxidized, as 9 is to 32*31. Now taking 9 as the equivalent
number of water, the number 32*5 is given as the equivalent
number of zinc; a coincidence sufficiently near to show, what
indeed could not but happen, that for an equivalent of zinc
oxidized an equivalent of water must be decomposed*.

867. But let us observe how the water is decomposed. It
is electrolyzed, i. e. is decomposed voltaically, and not in the
ordinary manner (as to appearance) of chemical decomposi-
tions; for the oxygen appears at the anode and the hydrogen
at the cathode of the decomposing body, and these were in
many parts of the experiment above an inch asunder. Again,
the ordinary chemical affinity was not enough under the cir-
cumstances to effect the decomposition of the water, as was
abundantly proved by the inaction on plate B ; the voltaic
current was essential. And to prevent any idea that the che-
mical affinity was almost sufficient to decompose the water,
and that a smaller current of electricity might, under the cir-
cumstances, cause the hydrogen to pass to the cathode, I need
only refer to the results which I have given (807. 813.) to
show that the chemical action at the electrodes has not the
slightest influence over the quantities of water or other sub-
stances decomposed between them, but that they are entirely
dependent upon the quantity of electricity which passes.

868. What, then, follows as a necessary consequence of the
whole experiment? Why, this: that the chemical action upon

* The experiment w«s repeated several times with the same results.

Absolute Quantity of Electricity in Matter. 437

32*31 parts, or one equivalent of zinc, in this simple voltaic
circle, was able to evolve such quantity of electricity in the
form of a current as, passing through water, should decom-
pose 9 parts, or one equivalent of that substance: and, con-
sidering the definite relations of electricity as developed in
the preceding parts of the present paper, the results prove
that the quantity of electricity which, being naturally asso-
ciated with the particles of matter, gives them their combining
power, is able, when thrown into a current, to separate those
particles from their state of combination ; or, in other words,
that the electricity "which decomposes^ and that which is evolved
by the decomposition of a certain quantity of 'matter ; are alike.

869. The harmony which this theory of the definite evolu-
tion and the equivalent definite action of electricity introduces
into the associated theories of definite proportions and electro-
chemical affinity, is very great. According to it, the equiva-
lent weights of bodies are simply those quantities of them
which contain equal quantities of electricity, or have naturally
equal electric powers ; it being the electricity which de-
termines the equivalent number, because it determines the
combining force. Or, if we adopt the atomic theory or
phraseology, then the atoms of bodies which are equivalents
to each other in their ordinary chemical action, have equal
quantities of electricity naturally associated with them. But
I must confess I am jealous of the term atom ; for though it
is very easy to talk of atoms, it is very difficult to form a clear
idea of their nature, especially when compound bodies are
under consideration.

870. I cannot refrain from recalling here the beautiful idea
put forth, I believe, by Berzelius (703.) in his development of
his views of the electro-chemical theory of affinity, that the
heat and light evolved during cases of powerful combination
are the consequence of the electric discharge which is at the
moment taking place. The idea is in perfect accordance with
the view I have taken of the quantity of electricity associated
with the particles of matter.

871. In this exposition of the law of the definite action of
electricity, and its corresponding definite proportion in the
particles of bodies, I do not pretend to have brought, as yet,
every case of chemical or electro-chemical action under its
dominion. There are numerous considerations of a theoreti-
cal nature, especially respecting the compound particles of
matter and the resulting electrical forces which they ought to
possess, which I hope will gradually receive their develop-
ment; and there are numerous experimental cases, as, for in-
stance, those of compounds formed by weak affinities, the

438 Dr. Faraday's Experimental Researches in Electricity,

simultaneous decomposition of water and salts, &c., which
still require investigation. But whatever the results on these
and numerous other points may be, I do not believe that the
facts which I have advanced, or even the general laws de-
duced from them, will suffer any serious change ; and they
are of sufficient importance to justify their publication, even
though much may remain imperfect or undone. Indeed, it is
the great beauty of our science, chemistry, that advancement
in it, whether in a degree great or small, instead of exhausting
the subjects of research, opens the doors to further and more
abundant knowledge, overflowing with beauty and utility, to
those who will be at the easy personal pains of undertaking
its experimental investigation.

872. The definite production of electricity (868.) in asso-
ciation with its definite action proves, I think, that the current
of electricity in the voltaic pile is sustained by chemical de-
composition, or rather by chemical action, and not by contact
only. But here, as elsewhere (857.)> I beg to reserve my
opinion as to the real action of contact, not having yet been
able to make up my mind as to its being either an exciting
cause of the current, or merely necessary to allow of the con-
duction of electricity, otherwise generated, from one metal to
the other.

873. But admitting that chemical action is the source of
electricity, what an infinitely small fraction of that which is
active do we obtain and employ in our voltaic batteries ! Zinc
and platina wires, one eighteenth of an inch in diameter and
about half an inch long, dipped into dilute sulphuric acid, so
weak that it is not sensibly sour to the tongue, or scarcely to
our most delicate test papers, will evolve more electricity in
one twentieth of a minute (860.) than any man would willingly
allow to pass through his body at once. The chemical action
of a grain of water upon four grains of zinc can evolve electri-
city equal in quantity to that of a powerful thunder-storm
(868. 861.). Nor is it merely true that the quantity is active;
it can be directed and made to perform its full equivalent
duty (867. &c). Is there noi, then, great reason to hope and
believe that, by a closer experimental investigation of the prin-
ciples which govern the development and action of this subtile
agent, we shall be able to increase the power of our batteries,
or invent new instruments which shall a thousandfold surpass
in energy those which we at present possess ?

874?. Here for a while I must leave the consideration of the
definite chemical action of electricity. But before I dismiss
this series of experimental researches, I would call to mind
that, in a former series, I showed that the current of electricity

Mr. Wheeler's Experiments in Photometry. 439

was also definite in its magnetic action (366. 367. 376. 377.);
and, though this result was not pursued to any extent, I have
no doubt that the success which has attended the development
of the chemical effects is not more than would accompany an
investigation of the magnetic phenomena.
Royal Institution, Dec. 31, 1833.

LXI. Experiments and Observations on the Application of
Photometry to certain Cases connected with the Undulatory
Theory of Light. By J. H. Wheeler, Esq.*

n^HE interest inspired by the discussions which have arisen
-*- within the last few years on the relative claims of the
corpuscular and undulatory theories of light, has been pro-
ductive of inestimable benefit to science. To Mr. R. Potter
the scientific world is certainly indebted for bringing forward
the first formidable objections, grounded on the application
of mathematical reasoning, to highly original experimental evi-
dence ; and whatever opinion may be entertained of the result
of the controversy, and the light thrown upon the question by
the various replies and rejoinders which have appeared, the
excellence of Mr. Potter's experimental labours, and the pro-
found ability with which he has maintained his side in the
controversy, cannot be too highly appreciated. And it emi-
nently deserves to be remembered, that with the most perfectly
philosophic love of truth, he has in a more recent paper can-
didly allowed the result of a long and laborious series of ex-
periments to be in favour of the theory he set out by op-
posing. (See this Journal, November 1833.) Still, however,
some of the principal objections brought forward by this gen-
tleman remain unanswered. I allude to those which depend
upon the calculated intensities of light in certain cases, which
are found totally to disagree with the observed intensities as
determined by his highly ingenious and admirably conducted
experiments, depending on the application of photometry,
which have appeared in several Numbers of this Journal.

Having felt from the first a deep interest in the subject, and
especially as connected with photometry, I have ever since
the publication of Mr. Potter's experiments been engaged,
as much as my other avocations would allow, in attempts to
repeat and verify them, and, if possible, to extend their ap-
plication to other cases. My labours hitherto have met with
but limited success, partly from the want of sufficient experi-
mental skill, but chiefly from some apparently insuperable

* Communicated by the Author.

440 Mr. Wheeler on the Application of Photometry

difficulties in the calculation of the results, which I am obliged
to confess I cannot bring into accordance with those of Mr.
Potter. My object, then, in the present communication will
be to state the results I have arrived at, such as they are, in
the hope that they will receive a candid examination. And in
order to afford all facilities for tracing out the cause of error
wherever it may lie concealed, and disentangling the subject
from its perplexities, I will first lay down the simple elementary
principles by which I have been guided in my calculations,
and which appear to me to involve the correct principles of
this branch of optical science.

The fundamental principle on which all photometrical com-
parisons must proceed is easily seen to be, the equalization
of the illuminating effects as estimated by the eye, and the
comparison of ,the distances of the luminous bodies necessary
to produce that equalization.

Now the illuminating effect is due jointly to the absolute
brightness of the luminous points, and the number of them ; or,
in jither words, the product of the intensity and the quantity
of fight.

For the same light at different distances (d), the intensity
(z) owing to the diffusion of the rays is inversely as d2, but
at the same time the apparent area into which the rays are
condensed diminishes, or the condensation increases, in the
same ratio ; hence on both considerations the intensity is con-
stant for all distances.

For different lights, the absolute intensity of each being thus
constant for all distances, the quantity of light varies with the
absolute area {a) directly, and the apparent visual area in-
versely ; thus, for the illuminating effect (I), we shall have

T *a

If we are examining the light reflected from a given sur-
face inclined to the direction of vision, it will be easily seen
that the inclination is the complement of the angle of reflection
($), and that instead of the absolute area (a) we must take
for the effective area a . cos <J>, or the illuminating effect will

be

I =

i . a . cos $

d2

And in comparing two lights, we shall have as a general formu-
la, to be modified to suit the particular cases which may arise,
(accenting the letters for the second light,)

I i . a. cos $ d,%
T '' i. a1, cos $' d* '

to the Undulatoty Theory of Light. 441

My first object was the comparison of the illumination in
the dark and bright parts of Newton's rings as in Mr. Potter's
experiments ; but here there are several difficulties of no small
magnitude to be encountered : first, we must suppose equal
portions of each dark and bright space, isolated so as to be-
come the fair objects of comparison for the intensity of light
they respectively give. In the next place, there is the radical
difficulty in using the apparatus which Mr. Potter so candidly
allows, which arises from the necessity for transferring the
eye from the inclined glasses to the rings alternately. For all
these difficulties, indeed, as Mr. Potter has justly observed,
there is no remedy but steady and repeated practice. By this
means, but certainly by no other, can the eye become suffi-
ciently accustomed to the work to be able to form an un-
hesitating decision, and to give confident approximations, at
least, to correct comparisons. After a tolerably long experi-
ence in this sort of experiment, I must candidly own that I have
never been able to feel that entire and perfect confidence in
such determinations which would suffice for resting upon them
any very nice and delicate conclusions. Yet I agree with
Mr. Potter, that long practice will enable us to attain a de-
gree of precision which at first sight would have appeared
hopeless.

I will not, however, dwell upon these points, but proceed
at once to detail my experiments, in which, with every degree
of care and caution, I have, owing to some cause at present
quite inexplicable to me, arrived at results very different from
those of Mr. Potter.

It will not be necessary for me to detail the construction
of my apparatus, because it was in every point precisely the
same as Mr. Potter's, for which I would refer the reader to
his paper in this Journal, September 1832, [Lond. and Edinb.
Phil. Mag. vol. i.] p. 174. I will simply proceed to give the
results of my experiments.

In this case the absolute areas of the two portions of in-
clined glasses are the same, or (using the accented letters to
apply to the second glass) a = a', and consequently by the
foregoing principles, we shall have (since d = d!)

I i cos $

V " if cos 4/ '

In order to find / and i' I have adopted Mr. Potter's valu-
able and curious formula for glass, which is, in fact, the basis
of all his calculations of these experiments; and I thus find
the following results, which will be best stated in a tabular
form.

Third Series. Vol. 5. No. 30. Dec. 1834. 3 L

442 Mr. Wheeler on the Application of Photometry

Homogeneous Red Light.

Glass for the
Dark Ring.
Incidence.

Glass for e
Light Ring.
Incidence.

Ratio rfr
by Formula above.

30°
30
40
40

70°

71

73

74

1-267
1-25
1-33
1-33

The results in this last column differ so widely from Mr.
Potter's, that I was led to examine several times over the
whole calculation ; but have been able to detect nothing which
can have led to error. I can therefore merely give my re-
sults as they stand, and those interested in the subject may
possibly be able to throw some light upon the point by further
examination.

I will only add, that with regard to the undulatory theory,
Mr. Potter's calculation of the ratio of illumination from that
theory, viz. 1*1538, approaches so much more nearly to agree-
ment with my results than he found it to do with his, that
perhaps we shall find the error (as there must be one some-
where) will in time show that there is in reality a still more
close accordance between theory and experiment. Indeed,
I will add that as Mr. Potter's calculation is founded upon
his estimate of ^th of the incident light being reflected from
glass, so from some trials of my own, (which I do not doubt
are of far inferior accuracy,) I found the proportion more
nearly g-'^th. Now this was quite independent of the last ex-
periments. And it is curious, that on calculation with this
number, in the way adopted by Mr. Potter, I find the re-
sulting ratio from theory about 1-25, which accords exactly
with these experiments.

I made other sets of experiments, as Mr. Potter did, to
compare the illumination from reflection at the surfaces of se-
veral different substances, with the view of comparing the re-
sults with the expression for such illumination derived from
the undulatory theory.

In the first instance I compared the effects of crown glass
and of a diamond possessing a tolerably good plane surface,
to the area of which that of the glass was carefully equalized :
we have then to find if (for glass), as before, by Mr. Potter's
formula, and since we here equalize the lights, or make

I = I' we have for diamond i m i' --.

cos<$

to the Undulatory Theory of Light,
The following are the results :

443

Incidence on
Diamond.

Corresponding

Incidence on

Glass.

Ratio of Reflection
by Formula.

3°
10
30
50
70

63°
63 48'
67

73 40'
79

20*6
18-8
24-5
27*9
49*3

I have not thought it necessary to follow out these results
through so long a series of incidences as Mr. Potter has done ;
but for the purpose of the results here aimed at, I have no
doubt these comparisons will be deemed sufficient. Here
again my resulting ratios differ most widely from those of
Mr. Potter ; yet they will be found to give (for the case of
perpendicular incidence) an agreement with theory, which is
fully as exact as can be expected from experiments of this na-
ture. The ratio from the undulatory theory as calculated by Mr.
Potter, being in this case 18*36, by my experiments it is 20'6.

Another set of experiments, conducted and calculated pre-
cisely in the same way, gave me very similar results for a sur-
face of glass of antimony.

Incidence on

Glass of

Antimony.

Corresponding

Incidence on

Glass.

Ratio of Reflection
by Formula.

0°
10
50
80

61°
61
66
80

16-4
16-6
17'
36-

For perpendicular incidence the undulatory theory gives the
ratio 13*33.

I have made other experiments with several substances,
which I will not now detail, as my principal object is answered
if I can draw attention to these results, so as to induce any
one sufficiently versed in the subject to investigate the source
of error, which somewhere and somehow has certainly crept
in, to give rise to the remarkable discrepancy between my re-
sults and those of Mr. Potter. Our data of observation, it
will be seen, agree in a singularly close manner, and the tri-
fling errors of observation are such as can in no way account

3 L2

444? Mr. Faraday on the Magnetic Spark and Shock.

for the differences in our results. It seems only possible to
account for it by some oversight in the calculations ; but
where it lies I am totally unable to say. I have given at large
the principles on which my calculations are founded, which,
I believe, are in a mathematical point of view correct. At
any rate the subject eminently deserves further inquiry, which
I hope and trust it may receive from those who are much
better qualified than myself to do justice to it. Professional
avocations have, indeed, hindered me from going into as ac-
curate an examination of it as I could wish, and will, I fear,
(for some time at least,) prevent me from entering upon a si-
milar repetition of those other highly interesting photometricat
researches, which relate to the reflection from metallic sur-
faces, in which Mr. Potter has found such curious anomalies.
These, however, are not so immediately connected with the
object 1 had in view, which chiefly refers to the controversy
in regard to the undulatory theory. The experiments, how-
ever, on reflection from glass at different incidences have a
stronger claim to attentive examination, as forming the basis
of the calculation in all the other instances.
Queen Street, Nov. 1, 1834.

LXII. Additional Observations respecting the Magneto-electric

Spark and Shock. By Michael Faraday, Esq., D.C.L.,

F.R.S., %c.

To Richard Phillips, Esq., F.R.S., fyc.
My dear Sir,
IKE most things done in haste, my letter to you last
■" month involves several errors, some from want of atten-
tion, others from want of knowledge. Will you do me the
favour to print the present in correction of them ?

The first error consists in supposing the electricity of the
shock and the electricity of the spark (obtained at the moment
of disjunction) are due to different currents, page 351. They
are, as I find by careful experiments, due to the same current,
namely, one produced by an inductive action at the moment
when the current from the electromotor ceases.

If at p. 351, line 26, after "set in motion" be inserted
" through the body;" and at line 31, for " counter" be read
" second ", and if the above statement be allowed to stand for
that at the top of page 352, this error will be corrected.

The experimental results which I anticipated, page 352,
lines 31—35, and page 354, lines 26—32, do not occur ex-
cept under peculiar circumstances, and I am now aware why,
for natural reasons, they should not. All the effects, in fact,

On the Action of Oxalic Acid upon Chloride of Sodium. 445

belong to the inductive action of currents of electricity de-
scribed in the first section of the first series of my Experi-
mental Researches. I have investigated them to a consider-
able extent, and find they lead to some exceedingly remark-
able and novel consequences. I have still some points to
verify, and shall then think it my duty to lay them (in con-
tinuation of my first paper) before the Royal Society.
I am, my dear Sir, very truly yours,
Royal Institution, Nov. 20, 1834. MlCHAEL Fa RAD AY.

LXIII. On the Action of Oxalic Acid upon Chloride of So-
dium. By Mr. Arthur Thorold Wood.*

FT is not generally known that the decomposition of chloride
* of sodium may be readily effected by the action of oxalic
acid; indeed, it is presumed that the fact is altogether new, as
our best chemical authors make no mention of it.

That such decomposition does take place may be proved
by several simple experiments: for example, if chloride of
sodium and oxalic acid be distilled with water in a retort,
muriatic acid will pass over ; and when its production ceases,
upon allowing the contents of the retort to cool, a salt having
the characters of oxalate of soda will crystallize, mixed to a
certain extent with chloride of sodium according to the pro-
portions of the materials employed.

As the muriatic acid in this experiment is very dilute, and
as oxalic acid cannot exist in the free state without a certain
proportion of water, the fact of the decomposition of chloride
of sodium may be more satisfactorily proved by taking oxalic
acid in crystals, and fused chloride of sodium, reducing them
to fine powder, and heating them in a glass tube containing a
slip of litmus paper, when muriatic acid will be instantly and
copiously evolved, and the litmus paper, of course, reddened.
When the evolution of the muriatic acid gas ceases, the dry
contents of the tube may be transferred to a piece of pla-
tinum foil, and intensely heated before the blowT-pipe flame;
the oxalate of soda will decompose, and carbonate of soda
will remain in sufficient quantity to restore the blue of the
reddened litmus paper when wetted with water, or to change
the yellow of turmeric paper to brown.

If it be merely required to show that alkali is evolved from
chloride of sodium by the oxalic acid, it may be done simply
by heating the two, folded in a bit of platinum, for a minute
or so before the blow-pipe flame, then adding a drop of water
and applying the usual test papers.

* Communicated by the Author.

446 Prof. Phillips on Subterranean Temperature,

These experiments have not as yet been performed with
minute attention as to the proportions of the acting bodies,
although such investigation is contemplated ; but it is con-
cluded, that the chlorine of the chloride of sodium obtains
hydrogen from the water of the oxalic acid to evolve muriatic
acid gas, and that the sodium, obtaining its oxygen from the
oxygen of the water, forms soda, which combines with the
oxalic acid, forming oxalate of soda, decomposable at a red
heat into carbonate of soda.

The chloride of calcium also undergoes decomposition
when heated with oxalic acid, evolving muriatic acid gas, and
forming oxalate of lime, which upon the further continuance
of the heat leaves lime.

These researches will be extended to the other chlorides,
with the view of getting new results ; in the mean time it is
hoped that the facts now stated possess some claim to ori-
ginality.

LXIV. On Subterranean Temperature, as observed at a Depth
of Five Hundred Yards below the Level of the Sea, in La-
titude 54° 55' North, November 15, 1834. By John
Phillips, F.R.S., F.G.S., Professor of Geology in King's
College, London.*

1. rT1HOUGH, upon a review of the facts and reasonings
■*■ concerning the interior temperature of the globe, we
may freely admit that below a certain depth from the surface
the thermometric heat becomes continually greater as we de-
scend, so many sources of embarrassment occur in the prose-
cution of experiments, that it is by no means an unreasonable
scepticism to doubt, whether the law of the augmentation of
heat in proportion to the depth is even approximately known.
Those who, from local and practical experience, are the best
enabled to judge of the corrections required for the effects of
respiration, light, friction, and chemical action, on the one
hand, and of the ventilating air on the other, must allow that
the interference of these causes of error, though less consider-
able than is sometimes imagined, is of serious consequence
in so delicate an inquiry.

2. Immediately after leaving Edinburgh, in October, I was
at Newcastle for a week, and was informed by Mr. Hutton, of

* Communicated by the Author: in the Phil. Mag. first series, for 1823,
vol. Ixi. p. 347, 436, and vol. Ixii. p. 38, 94, will be found a review, drawn
up by Mr. Brayley, Jun., of the experiments on Subterranean Temperature
which had then recently been made in the Mines of Cornwall and the North
of England, exhibited in a tabular form. See also vol. Ixvii. p. 302, and Phil.
Mag. and Annals, N.S. vol. ix. p. 94.

as observed at a Depth of 500 Yards, at Monk- We at mouth . 447

the spirited attempt of Mr. Pemberton to reach the coal-seams
which underlay the magnesian limestone of Durham, by a
shaft at Monk-Wearmouth which had then reached the ex-
traordinary depth of 250 fathoms. I mentioned to M. Arago,
while he was in Newcastle, my great desire to examine in this
pit, the question of subterranean temperature, before the or-
dinary processes of a deep colliery had complicated the inves-
tigation with unascertainable conditions; and was happy to
find that a view which I had formed, of relying very much
on trials made in subterranean small feeders of water, met
with his approval.

3. Professor Whitley, of Durham, had also considered the
subject in another point of view, and on my return to New-
castle, I found my friend Mr. W. L. Wharton, of Dryburn,
engaged in arrangements for a course of experiments in the
pit, which, at the enormous depth of 264 fathoms, had passed
through a seam of coal 6 feet in thickness. Every facility
being kindly offered by the proprietors of the colliery, (Messrs.
Pemberton and Mr. Thompson,) I descended the pit for the
purpose of the experiments on Saturday the 15th of Novem-
ber, at 1 1 a.m., and remained nearly four hours underground,
with the following gentlemen, viz. Mr. W. L. Wharton, Pro-
fessor Whitley, Rev. Prof. Chevallier, Prof. Johnston, Mr.
G. C. Atkinson, and several others.

Barometers and thermometers were taken by Mr. Wharton
and myself, and each of the other gentlemen was provided
with a thermometer. On a comparison of thermometers from
47° to 70°, it was found that Mr. Whitley's (by Adie) agreed
with one constructed by myself. By this standard, all the
observations are recorded, proper corrections being applied
to the other instruments.

4. The pit is 12 feet in diameter, partitioned in the usual

Seam of coal at 264 fathoms.
Bottom of Pit.

manner, and tubbed in parts to stop the entrance of water,

448

Prof. Phillips on Subterranean Temperature,

which nevertheless drops, but not in great quantity, down the
sides. This water falls several yards below the coal seam in
which our experiments took place, into the bottom of the pit,
which is to be carried considerably deeper to a lower bed of
coal.

On arriving at the point a, we entered on the nearly level
floor of the coal, and found four narrow headings driven short
distances E., W., N., and S. Strong currents of air were
established along the headings to sweep the fresh face of coal,
from all points of which the carburetted hydrogen gas was
heard to issue with a faint tinkling or humming noise, like
that which might arise from the vibration of innumerable
very small kettles. This gas was carried off too rapidly by
the currents of air to permit any exhibition of phenomena de-
pending on its inflammable properties, even when the Davy-
lamp was placed in angles of the front of the coal.

By the care of Mr. Foster, the intelligent viewer, a hole
was drilled in the floor of the coal seam on the dip side (east)
to the depth of two feet ; and when Mr. Wharton and I reach-
ed the seam, this hole was completed, and full of salt water.
This station is marked A on the accompanying plan ; it is
22 yards from the pit.

~ B C D

PPBIK

5. The first experiment was made by my going instantly to
the bore-hole A, and trying the temperature of the water
which had risen in it. By most careful observations it was
found to be 70' 1. The air in the drift was generally 62°;
this was the temperature of the air in the porch G : it pre-
vailed also along the drift E, in which no one was at work,
till near the forehead, when it rose to 64°, and close to the coal
among the humming gas, which would not fire, it was 68°.

as observed at a Depth of 500 Yards, at Monk-Wearmouth. 449

Each of the thermometers belonging to the party was
plunged in the bore-hole A, and the temperature was uni-
formly found about 70°, allowance being made for the differ-
ence of the graduation of the instruments.

6. Mr. Wharton now caused excavations to be made in the
floor of the east drift to the depth of about nine inches, and
quickly inserted in each a minimum thermometer, previously
heated to about 75° — 80°, and left them for half an hour. The
temperature of the air near the surface of the floor at each point
was 62° to 63° ; that of the loose small coal on the surface 64°
to 67°. It was found upon two trials that at the point D,
nearest the pit, the temperature at this depth was 64°*5 ;
at C, further in, 66°*4 ; at B, six yards from the forehead,
69°*4 and 69°'9. We then chose a point near A, within two
or three yards of the forehead, and sunk the instrument
deeper, so that it was quickly surrounded by the gushing salt
water : when taken up it stood at 71°'4.

7. We next determined to try the temperature of a fresh
face of coal, by picking off a few inches in depth, and placing
the thermometer in contact with the fresh face and its bulb
among the particles which had fallen. The first rough trial
gave 69°; the next a temperature continually rising till it
settled at 71i°.

8. In trying again the temperature of the bore-hole A, we
observed that the thermometer fluctuated through a full de-
gree, being highest whenever bubbles of gas rose more rapidly
through the water, and lowest when these ceased for a while.
It was also found that this water, notwithstanding the effect of
human bodies, lights, &c, was continually cooling by the cur-
rent of air in the drift. At 2 p.m. its temperature was 69°*7
when air-bubbles rose in abundance, and 69°*1 when this was
not the case. Some time later it was again registered 69°*6
and 69°*3.

Finding this to be uniformly the case, we returned to the
little pit near A, and found by a delicate thermometer the
temperature of the water when bubbles abounded to be 72°*6,
and 71°*6 and 72°# when they ceased.

9. While these experiments were in progress, Mr. Whitley
caused a hole two feet six inches in depth, to be made in the
floor of the coal in the forehead of the west or rise drift F,
and in this he poured water at 56° Fahr., and then with parti-
cular precautions introduced a thermometer at 2 p.m. The
men were directed to abstain from entering this drift, till, on
Monday morning, after an interval of two days, Mr. Whitley
returned, and with Mr. G. Atkinson, drew out the thermo-
meter and found it to stand at 71°*2. As Mr. Whitley has

Third Series. Vol.5. No. 30. Dec. 1834. SM

450 Prof. Phillips on Subterranean Temperature.

made arrangements for repealing this interesting experiment,
under different conditions, I shall not further anticipate the
account, which I hope he will soon publish, of the result of
his labours.

10. The temperature of the water collected in the pit bot-
tom was 67°. The barometric observations were :

B.P. Att.Th. Det. Th.
At the top .... at 11 a.m. 30*518 53° *9°1 It is a boiled
At the bottom at 1 1 a.m. 32-280 58 62 Vtube absolutely
At the top .... at 3 p.m. 30*518 58 49 J free from air.
Capacity of instrument ^y*

11. On these results I beg leave to offer a few remarks.
The temperature of surfaces of rock exposed in subter-
ranean situations is subject to several modifying causes.

1. The real interior temperature of the mass ;

2. The local influence of external heating agents, which
are, respiration of workmen, lights, explosions, and fric-
tion ;

3. The variable influence of the air which is made to cir-
culate through the passages of the works.

12. It is evident that the most satisfactory experiments are
those in which the local and variable influences are the least
possible, or else the most easily ascertainable : they cannot be
wholly annihilated. In the present instance the small extent
of the underground workings is very favourable ; they are, in
fact, only just commenced; no horses are yet let down into
the pit; the extrication of gas from the fresh coal is so abun-
dant as to compel the use of the Davy-lamp, and to require
a very powerful ventilation. It is a circumstance too im-
portant to be overlooked, that the total influence of the ex-
ternal agents on temperature is the resultant of the heating
and cooling agency of the men, lights, currents of fresh air,
&c. If this total influence, in any part of the mine, be to aug-
ment the temperature of the surfaces, the interior parts will
be found colder than the surface, and the contrary.

Now in the present instance, it was found that the resultant
of the external influences on the surface of the coal was
powerfully refrigerating ; for in those parts which were con-
tinually and had been long exposed to them, the surface tem-
perature was either the same or a few degrees above that of
the air ; in the parts which had been less exposed, this tem-
perature was higher: when fresh surfaces were exposed it
was highest of all, being 9° 6' above that of the air current.
As the workings proceed this great difference will probably
diminish, and then it may be not possible so clearly to prove

Royal Society. 451

the important truth, that the hottest part is that furthest re-
moved from external modifying causes.

13. The salt water springing up in the floor of the coal,
on the dip side, is a favourable circumstance. Its tempera-
ture, like that of the fresh rock, is highest when first tried: by
exposure to the external agent it is cooled nearly a degree in
three hours, from a temperature which was already nearly
2° too low.

14-. The gas, which is constantly bubbling out from its cel-
lular reservoirs, brings more completely, perhaps, than any-
thing else, the real temperature of the interior. It no doubt
supplies warmth to the surface of the coal, and was found
hotter than the water through which it rose by no less than a
degree.

15. Mr. Whitley's experiment is surely liable to no ob-
jection but one, viz. that the pouring of water at 56° into
so bad a conductor as coal, was likely to give a result rather
below the truth.

16. I have said nothing of local chemical action, since in
this situation no indications of oxides or salts of iron, or
other products, depending on decomposition of pyrites, or
other probable sources, have as yet manifested themselves. Be-
sides this, all the deep coal-works of this country, as I learn
from Mr. Buddie, agree in proving the augmentation of tem-
perature to be a general fact, independent of the pure or
pyritous quality of the coal, and of the development of inflam-
mable gas.

17. The total depth of the floor of the coal is 1584 feet;
the pit top is 87 feet above ordinary high water; its depth
below the level of the sea, 1497 feet. If the depth of the in-
variable plane be taken at 100 feet, and the mean tempera-
ture of the place 47°*6, we have 72°*6 — 47°'6 = 25°*0 aug-
mentation of temperature in 1484 feet = 1° for 59*36 feet, or
in round numbers 1° Fahr. for 20 yards English.

Newcastle, Nov. 18, 1834.

LXV. Proceedings of Learned Societies.

ROYAL SOCIETY.

[Continued from vol. iv. p. 441.]

1834. A PAPER was read, entitled, " Of the Functions of

May 15. — -tlm. some parts of the Brain ; and of the relations between

the Brain and Nerves of Motion and Sensation." By Sir Charles

Bell, K.H., F.R.S.

The author commences his paper by an enumeration of some of the
sources of difficulty and of error which have impeded the progress of

3M2

4:52 lloyal Society.

discovery in the physiology of the brain ; the first impediment to
which, he observes, " is in the nature of the inquiry, since extraor-
dinary and contradictory results must be expected from experiment-
ing on an organ so fine as that must be which ministers to sensibility
and motion, and which is subject to change on every impression con-
veyed through the senses." Another cause of fallacy is the depend-
ence of the brain on the condition of the circulation within it : but
the most frequent source of error is the obscurity which hangs over
the whole subject j for although the brain be divided naturally into
distinct masses, not one of these grand divisions has yet been distin-
guished by its functions -, and hence we may account for the failure
of all attempts to explain the phenomena which attend injury of the
brain. The principle, now universally admitted, that nerves have
distinct functions, and not a common quality, is pursued by the
author in his investigation of the structure of the brain, in which he
follows the nerves into that organ, and observes the tracts of nervous
matter from which they take their origin. He concludes from his in-
quiries that both sensibility and motion belong to the cerebrum ; that
two columns descend from each hemisphere ; that one of these, the
anterior, gives origin to the anterior roots of the spinal nerves, and
is dedicated to voluntary motion ; and that the other, which from its
internal position is less known, gives origin to the posterior roots of
the spinal nerves, and to the sensitive root of the fifth nerve, and
is the column for sensation. He further shows that the columns for
motion, which come from different sides of the cerebrum, join and
decussate in the medulla oblongata j that the columns of sensation
also join and decussate in the medulla oblongata ; and lastly, that
these anterior and posterior columns bear, in every circumstance, a
very close resemblance to one another, in as much as the sensorial ex-
pansions of both are widely extended in the hemispheres j for they
pass through similar bodies towards the base of the brain, and both
concentrate and decussate in the same manner j thus agreeing in
every respect, except in the nervous filaments to which they give
origin. Hence he explains the phenomena of the loss of sensibility
as well as the power of motion of one side of the body, consequent
on injuries of the other side of the brain.

The Society then adjourned over Whitsun Week to the 29 th of May.

May 29. — A paper was read, entitled, " On the Principle of Con-
struction and General Application of the Negative Achromatic Lens
to Telescopes and Eyepieces of every description." By Peter Barlow,
Esq., F.R.S.

This paper is intended as a more full illustration of the principles
on which the negative achromatic lens is constructed and applied, than
has been given in the extract from the author's letter to Mr. Dollond,
contained in the paper of the latter, lately read to the Society, on his
ingenious application of that lens to the micrometer eyepiece*. The
author shows that its advantages are not confined to this instrument,

* An abstract of Mr. Dollond's paper appeared in Lond. and Edinb. Phil.
Mag., vol. iv. p. 364.

Royal Society. 453

but that it is applicable to any eyepiece positive or negative to the
erecting eyepiece, and, indeed, to any telescope of fluid or glass, and
also to refractors.

A paper was also read, entitled, " Some remarks in reply to Dr.
Daubeny's Note on the Air disengaged from the Sea over the site of
the recent Volcano in the Mediterranean." By John Davy, M.D.,
F.R.S. Assistant Inspector of Army Hospitals.

Respecting the air in question, which Dr. Davy had found to con-
sist of about 80 per cent, of azote and 10 oxygen, he had remarked
that two views might be taken of its origin ; the one, that it was of
volcanic source ; the other, that it was derived from the sea water,
and merely disengaged by the heat of the volcano. Dr. Davy, reject-
ing the former of these views, had adopted the latter, for reasons, the
validity of which was controverted by Dr. Daubeny* j and the purpose
of the present paper is to answer the objections urged against them,
and to bring additional evidence in support of his opinion.

A paper was then read, entitled, "On the number of Primitive
Colorific Rays into which White Light may be separated." By Paul
Cooper, Esq. Communicated by J. G. Children, Esq. Sec. R.S.

From a consideration of the circumstances in which white light is
decomposed by the prism, in different experiments, and of the various
appearances of the spectra which result, the author is led to the
opinion that the primary colours composing white light are not
seven, as conceived by Newton j nor four, as supposed by Wollas-
ton j but only three: and that these three are not red, yellow, and
blue, as imagined by Brewster, but red, green, and violet; the
first and last forming the terminal parts of the spectrum, and the
green occupying an intermediate position ; and the various tints
which intervene being the result of superpositions, in various quan-
tities, of these respective primary colours. He pursues the conse-
quences of this hypothesis, applying it to a great variety of forms of
experiment, not only by the direct observation of beams of refracted
light, but by viewing the prismatic spectrum through different media,
capable of absorbing each of the primitive colours in different degrees :
and he finds the results to accord exactly with the hypothesis he pro-
poses, and on which he therefore concludes that their true explanation
must be founded. He conceives that the errors of preceding experi-
mentalists have arisen from their neglecting to take into account the
effects of diffraction, which introduces considerable confusion into the
results.

A paper was also read, entitled, •* An Investigation of the Laws
which govern the Motion of Steam- Vessels, deduced from expe-
riment." By P. W. Barlow, Esq. Civil Engineer. Communicated
by Dr. Roget, Sec. R.S.

The author commences with the description of a paddle-wheel for
steam-vessels, of a new construction, in which the floats are made to
enter and leave the water nearly in a vertical position. He then inves-
tigates several formulae adapted to the calculation of the forces and

* An abstract of Dr. Daubeny's note was given in vol. iii. p. 447.

454 Royal Society.

velocities arising from this form of the apparatus ; and gives an ac-
count of the results of various experiments made on its efficiency as
compared with the common wheels, and with relation to the con-
sumption of fuel. The general results to which he is led are as fol-
low : — 1st. When vessels are so laden as that the wheel is but
slightly immersed, little advantage is derived from the vertically acting
paddles. 2ndly. In cases of deep immersion, the latter has consi-
derable advantage over the wheel of the usual construction. 3rdly. In
the common wheel, while the paddle passes through the lower portion
of the arc, that is when its position is vertical, it not only affords
less resistance to the engine, but is less effective in propelling the
vessel than in any part of its revolution. 4thly. The paddle of the
wheel, while passing through the lower portion of the arc, affords
more resistance to the engine, and is more effective in propelling the
vessel, than in any part of its revolution j a property which is a serious
deduction from its value j for, in consequence of the total resistance
to all the paddles being so much less than in the common wheel,
much greater velocity is required to obtain the requisite pressure,
and a greater expenditure of steam power is incurred. This loss of
power is most sensible when the wheel is slightly immersed j but in
cases of deep immersion the vertical paddle has greatly the advantage,
othly. In any wheel, the larger the paddles the less is the loss of*
force ; because the velocity of the wheel is not required to exceed that
of the vessel in so great a degree, in order to acquire the resistance
necessary to propel the vessel, fithly. With the same boat and the
same wheel no advantage is gained by reducing the paddle so as to
bring out the full power of the engine ; the effect produced being sim-
ply that of increasing the speed of the wheel, and not that of the ves-
sel. 7thly. An increase of speed will be obtained by reducing the
diameter of the wheel ; at least within such limits as allow of the
floats remaining sufficiently immersed in the water; and provided the
velocity of the engine does not exceed that at which it can perform
its work properly. Sthly. An advantage would be gained by giving
to the wheel a larger diameter, as far as the immersion of the pad-
dles produced by loading the vessel would not so sensibly affect the
angle of inclination of the paddle ; but this advantage cannot be ob-
tained with an engine of the same length of stroke, because in order
to allow the engine to make its full number of strokes, it will then be
necessary to diminish the size of the paddles, which is a much
greater evil than having a wheel of smaller diameter with larger
paddles.

The reading of a paper was then commenced, entitled, " On the
Equilibrium of a Mass of Homogeneous Fluid at liberty." By James
Ivory, Esq., K.H., M.A., F.R.S.

June 5. — Mr. Ivory's paper, entitled, " On the Equilibrium of a
Mass of Homogeneous Fluid at liberty," was resumed and concluded.

The author shows that Clairaut's theory of the equilibrium of fluids,
however seductive by its conciseness and neatness, and by the skill
displayed in its analytical construction, is yet insufficient to solve
the problem in all its generality. The equations of the upper surface

'Royal Society, 455

of the fluid, and of all the level surfaces underneath it, are derived,
in that theory, from the single expression of the hydrostatic pressure,
and are entirely dependent on the differential equation of the surface.
Thev require, therefore, that this latter equation be determinate and
explicitly given ; and accordingly they are sufficient to solve the
problem when the forces are known algebraical expressions of the
co-ordinates of the point of action ; but they are not sufficient when
the forces are not explicitly given, but depend, as they do in the
case of a homogeneous planet, on the assumed figure of the fluid. In
this latter case, the solution of the problem requires, further, that the
equations be brought to a determinate form by eliminating all that
varies with the unknown figure of the fluid ; and the means of doing
this are not provided for in the theory of Clairaut, which tacitly as-
sumes that the forces urging the interior particles are derived from
the forces at the upper surface, merely by changing the co-ordinates
at the point of action. In the case of a homogeneous planet, the
forces acting on the interior particles are not deducible, in the manner
supposed, from the forces at the surface.

After showing that the equilibrium of a fluid, entirely at liberty,
will not be disturbed by a pressure of the same intensity applied to
all the parts of the exterior surface, the author considers the action
of the forces upon the particles in the interior parts of the body of the
fluid ; and shows that although the forces at the surface are uni-
versally deducible from the general expressions of the forces of the
interior parts, yet the converse of this proposition is not universally
true, the former not being always deducible from the latter ; a di-
stinction which is not attended to in Clairaut's theory. He then in-
vestigates the manner in which these two classes of forces are con-
nected together; establishes a general theorem on the subject; and
proceeds to its application to some of the principal problems, relating
to the equilibrium of a homogeneous fluid at liberty, and of which the
particles attract one another with forces, first in the inverse duplicate
ratio, and secondly in the direct ratio of the distance, at the same
time that they are urged by a centrifugal force arising from their re-
volution round an axis. The author concludes with some remarks on
Maclaurin's demonstration of the equilibrium of the oblate elliptical
spheroid ; and on the method of investigation followed in the paper
published in the Philosophical Transactions for 1824*. In an Appendix
the author subjoins some remarks on the manner in which this sub-
ject has been treated by M. Poisson.

The reading of a paper was then commenced, entitled, " Experi-
mental Researches in Electricity;" Eighth Series." By Michael
Faraday, Esq., D.C.L., F.R.S.

June 12. — A paper was read, entitled, "On the Arcs of certain
Parabolic Curves." By Henry Fox Talbot, Esq., M.P., F.R.S.

The general equation to parabolic curves, (namely, nu = vn ; where
u is the abscissa and v the ordinate, ) gives for the arc of the curve an

* A paper by Mr. Ivory also relating to ihis subject will be found in Phil.
Mag., vol. lxiii. pp. 339, 347.

4 56 Royal Society: — Prof. Faraday on the Origin

expression which, excepting in a very few instances, is transcendental.
But although the length of an arc, considered by itself, cannot be as-
signed algebraically, yet it frequently happens that the sum of two or
more arcs is capable of being so assigned, and sometimes in a very
simple manner. The author has found this reduction to take place in
so many instances, as to incline him to believe that it may be uni-
versally possible, provided the exponent (») of the ordinate in the
equation to the curve is a rational quantity of these reductions : he
gives a great number of examples ; but although the processes for
that purpose are easy, the difficulty consists wholly in findir.g the
proper method of treating each individual case. The author hopes to
lay before the Society, on a future occasion, an account of the prin-
ciples on which this branch of analysis is founded.

Mr. Faraday's Eighth Series of Experimental Researches in Elec-
tricity was resumed and read in continuation.

June 19. — The reading of Mr. Faraday's Eighth Series of Experi-
mental Researches in Electricity was resumed and concluded.

This series is devoted to an investigation of the source, character
and conditions of the electricity of the voltaic instrument, and is di-
vided into five parts. In the first part, simple voltaic circles are con-
sidered ; and at the outset, the great question of " whether the elec-
tricitv is due to contact or chemical action ?" is investigated and de-
cided by apparently very conclusive evidence in favour of the latter.
One principal experiment in favour of this decision is the following:
A plate of zinc and a plate of platina were prepared; one end of each
of these was put into a vessel containing a little dilute sulphuric acid
or sulpho-nitric acid, and between the other ends was placed a piece
of bibulous paper moistened in a solution of iodide of potassium : the
two plates did not touch each other anywhere, but still the action of
the acid at the one extremity was able to induce the electro-chemical
decomposition of the iodide of potassium at the other. That this de-
composition was due to the chemical action of the acid was proved by
removing the latter ; for then the decomposition ceased. It was also
further proved by the appearance of the iodine against the platina ;
for it went there in consequence of the passage of a current (induced
by the action of the acid) having the opposite direction to that which
the solution of iodide would have produced had it been the only ex-
citing body, and had metallic contact been allowed.

The opposition of the chemical affinities at the two places where
the acid and the solution of the iodide are placed, is shown when the
metal plates are allowed to touch each other in the middle - for then
two opposite electric currents are produced, but that occasioned by
the acid is the stronger. This opposition is further shown in the
manner in which the weaker set of affinities are overcome by the
stronger (that is, those of the iodide and zinc by those of the acid and
zinc) j and this dependence and relation of the two explains at once
the value of metallic contact ; for if the solution of iodide of potassium
be placed between platina and platina, one of those pieces of metal
touching the zinc which is immersed in the acid, then the solution of
iodide does not tend to throw an electric current into circulation,

of the Electricity of the Voltaic Pile. 457

because it exerts no chemical action in either direction ; and therefore
the powers active in the acid are more free to act, produce a stronger
current, and effect decomposition more freely.

The chemical actions at the opposite ends of the metallic arrange-
ment are so strongly associated and related, that in the most perfect
form of experiment, action cannot occur at either end without also
taking place at the other extremity to an exactly equivalent amount.
This is considered by the author as the most convincing proof that in
the voltaic pile the chemical and electric action are the same -, that is,
modes of exhibition of the same force, and as they are convertible into
each other in exactly definite proportion, must have onecommon origin.

By using different fluids at the exciting place of action, currents
of different, intensity could be obtained : thus the current produced
by the action of dilute sulphuric acid on zinc and platina could de-
compose elsewhere solution of iodide of potassium, fused protochloride
of tin, or chloride of silver ; but could not decompose water, muriatic
acid, nitric acid, or the chloride or iodide of lead. Making the dilute
sulphuric acid stronger, or using larger plates of zinc and platina, did
not yield any advantage 5 but immediately that the chemical action
on the zinc was increased in intensity, which could be done by adding
only a few drops of nitric acid, then most of the latter bodies could
be decomposed by a single pair of plates. A scale of initial intensities
can in this way be obtained.

The electricity evolved in the voltaic pile is altogether due to that
chemical action which takes place between the metal most easily
acted upon and the element which unites with it j as, for instance,
between the zinc and the oxygen of the water, or the chlorine of the
muriatic acid, or the sulphur of hydrosulphurets, &c. ; the after action
of the acid in combining with the oxide, when that is the substance
formed, adds nothing to the effect. The truth of this principle is de-
duced in the first place from the electricity evolved being the equiva-
lent of the zinc oxidized -, in the second, from the quantity of elec-
tricity being the same for the oxidation of a given quantity of zinc,
whether the oxide formed is removed by an acid or an alkali ; and it
is supported by many other experimental reasons and proofs.

The view which the author takes of the identity of electrical and
chemical action, leads him to admit that there are two modes of action
in which the attractive power of the substances which ultimately
combine, and by combining give the voltaic pile activity, can be ex-
erted. Thus, taking zinc and platina as the two metals used, then
the third substance must be an electrolyte ; that is, a body which is
decomposed when the electric current passes it ; which cannot conduct
the current unless it is at the same time decomposed j and which con-
tains an element having such attraction for the zinc that the latter
can take it from the element with which it is previously combined.
Water is the electrolyte generally present in the voltaic pile.

Then, with respect to the attraction between the zinc and the

oxygen of the water, we have it in our power to cause it to take place

at once when the metal and water are in contact, the hydrogen being

then set free ; or we can, bv using the precautions which the author

Third Series. Vol. 5. No". 30. Dec. 1834. 3 N

458 Royal Society : — Prof. Faraday on the Voltaic Pile.

gives, cause that no action take place, unless a current be formed and
the hydrogen be transferred to a distance, whilst the forces circulate
in what is called the electric current. Placing the origin of the cur-
rent in the chemical action, which yet could be thus virtually restrained
unless the circuit was completed, the author expected to find a state
of tension in the chemical or electrical forces before metallic contact
was made or the circuit perfect, and was able at last to prove this most
fully by obtaining an electric spark between two plates of different
metals immersed in acid before they came in contact. This fact, with
the former one of decomposition, fully proved that contact was not
necessary to the production of the electricity in the voltaic pile.

The second part of this memoir contains an investigation of the fol-
lowing important points : namely, whether electrolytes could resist
the action of an electric current if below a certain intensity ; whether
the intensity at which an electric current might cease to act would be
the same for all bodies ; and also whether the electrolytes, when thus
resisting decomposition, would conduct the electricity as a metal or
charcoal does, after they ceased to conduct as electrolytes, or would
act as insulators. It is first proved with regard to water, that a cur-
rent of a certain intensity is necessary for its decomposition, but that
a current of a lower intensity is conducted by it j and that with such
feeble currents, pure water conducts as well as acidulated water or
saline solutions. The same condition of a certain necessary intensity
of current was found to hold good also with sulphate of soda in solu-
tion, with fused chloride of lead and other bodies, and is considered
by analogy as extending to all electrolytes.

In the third part of the paper, associated voltaic circles, or the
voltaic battery, is examined. From the principles and facts stated in
the preceding parts, it appears evident that the association of many
pairs of plates, equal in size, nature and force, cannot by any possi-
bility increase the quantity of electricity above that which any single
pair in the series could produce, taking the quantity of zinc oxidized
at any one plate as the standard of development. It is easy, by using
amalgamated zinc, to construct a battery in which no action shall
take place on the metals, except the extremities be in communication.
If a battery of ten pairs of plates be thus communicated, there is of
course oxidation of each zinc plate, and a current of electricity cir-
culates. If the contact of the extremities be continued until a cer-
tain quantity of zinc has been dissolved at any one plate, it will be
found that an exactly equal quantity has been dissolved at each of the
other plates ; and that a certain quantity of electricity has passed,
which can be taken cognizance of by the volta-electrometer. But
should nine of the pairs of plates be removed and the battery be re-
duced to a single pair, yet when the given quantity of zinc had been
dissolved there, as much electricity would have gone round the circuit
as with the whole number of ten pairs, and during the evolution of
which ten times the quantity of zinc had been oxidized.

This result, already proved by electro-magnetic experiments, is
shown to be a necessary consequence of the construction of the pile
and the manner in which its forces act. The electricity evolved by

Dr. Agassiz on the Classification of Fish. 459

chemical action at one pair of plates cannot pass by another pair ex-
cept an equal chemical action take place there ; and as the chemical
and electrical action are always equivalent, the equal chemical action
at the second pair will do no more than suffice to transfer forwards the
forces disturbed at the first pair, and can add nothing to their quan-
tity : but they can add to their intensity, and in fact the recurrence
of a second chemical action at the second pair of plates has exactly
the same effect as would be produced by a more intense chemical ac-
tion at the first pair. In this way it is that numbers of plates give
energy to the voltaic pile, and enable its power to penetrate elec-
trolytic bodies and permeate bad conductors in a manner which could
not be done by the electricity of a few pairs of plates only.

The fourth part of the paper relates to the resistance opposed to
the electric current at the place of decomposition, and refers this at
once to the resistance of the chemical affinity which has to be over-
come. This of course varies with the number of places where de-
composition is effected, the strength of the affinity of the elements of
the decomposing body for each other, and the nature of the substance
against which the decomposition is effected, and by which it may very
frequently be assisted. All these are taken into account, their ge-
neral, and occasionally particular, results shown, and their perfect
harmony with the principles previously advanced pointed out.

In the last part of the paper some general remarks on the active
voltaic battery are made, in which the influence of several distinct
causes in producing a rapid change and deterioration of action is
pointed out. Each of these causes is considered separately, and the
effects they produce are shown to be necessary consequences of the
principles already laid down as those of the voltaic battery.

GEOLOGICAL SOCIETY.

Nov. 5, 1834?. — The Society assembled this evening for the Session.
A paper was read " On a new Classification of Fishes, and on the Geo-
logical Distribution of Fossil Fishes," by Prof. Agassiz, of Neuchatel.

The author begins by stating that the state of the science of Ich-
thyology had obliged him to undertake an examination of recent
fish for the sake of comparing them with the fossil species, and in
doing so he had arrived at a classification offish, in general, differing
considerably from the various arrangements previously adopted by-
naturalists. One of the essential characters of fish is, to have their
skin covered with scales of a peculiar form and structure. This co-
vering, which protects the animal without, is in direct relation with
its internal organization, and Dr. Agassiz has found that by an at-
tentive examination of the scales, fish may be divided into more na-
tural orders than had hitherto been established. In this manner he
has established four orders, which bear some relation to the divisions
of Artedi and Cuvier, but one of which, hitherto completely misun-
derstood, is almost exclusively composed of genera whose species
are only found in the most ancient strata in the crust of our globe.
These four orders are, the Placoidians, which comprehend the car-
tilaginous fish of Cuvier, with the exception of the sturgeon j the

3N2

460 Geological Society : — Dr. Agassiz on the

Ganoidians, which comprehend above fifty extinct genera, and to
which we must refer the Plectognaths, Syngnathus, and Acipenser ;
thirdly, the Ctenoidians^ which are the Acanthopterygians of Cuvier
and Artedi, with the exception, however, of those which have smooth
scales, and with the addition of the Pleuronectes. Lastly, the Cy-
cloidians, which are principally Malacopterygians, but which com-
prehend besides all those families excluded from the Acanthoptery-
gians of Cuvier, and from which we must take the Pleuronectes
already placed in the preceding order.

If we estimate the number offish now known to amount to about
eight thousand, we may state that more than three fourths of this
number belong to two only of the above-mentioned orders ; namely,
the Cycloidians and Ctenoidians, whose presence has not yet been
discovered in the formations inferior to the chalk. The other fourth
part of living species is referrible to the orders Placoidians and Ga-
noidians, which are now far from numerous, but which existed
during the whole period which elapsed since the earth began to be
inhabited, to the time when the animals of the greensand lived.
These remarkable conclusions to which M. Agassiz had come, from
the study of more than six hundred fossils on the Continent, have
been corroborated by the inspection of more than two hundred and
fifty new species found in English collections.

The author next observes that in the class of fish more consider-
able differences may be remarked within narrow geological limits
than among inferior animals. We do not see in the class of Fishes
the same genera, nor even the same families, pervading the whole
series of formations as takes place among Zoophytes and Testacea.
On the contrary, from one formation to another, this class is repre-
sented by very different genera, referable to families which soon
become extinct, as if the complicated structure of a superior organi-
zation could not be long perpetuated without important modifica-
tions; or rather, as if animal life tended to a more rapid diversifica-
tion in the superior orders of the animal kingdom, during equal
periods of time, than in its lower grades. With respect to this, it is
with fish nearly as with mammifers and reptiles, whose species, for
the most part but little extended, belong at a short distance in the
vertical series to different genera, without passing insensibly from
one formation to another, as is generally admitted to be the case
with certain shells. One of the most interesting facts which Mr.
Agassiz has observed is, that he does not know a single species of
fossil fish which is found successively in two formations, whilst he
is acquainted with a great number which have a very considerable
horizontal extent. But the class of Fish presents besides to Zoolo-
gical Geology, the immense advantage of traversing all formations.
Thus they afford us the only example of a great division of verte-
brated animals in which we may follow all the changes experienced
in their organization during the greatest lapse of time of which we
possess any relative measure.

The fish of the tertiary formations approach nearest to recent fish,
yet hitherto the author has not found a single species which he con-

Geological Distribution of Fossil Fish. 4-61

sillers perfectly identical with those of our seas, except the little fish
which is found in Greenland in geodes of clay, and whose geologi-
cal age is unknown to him.

The species of the crag of Norfolk, the superior subapennine for-
mation, and the molasse, are related for the most part to genera
now common in tropical seas ; such are the Platax, the large Car-
charias, the Myliobates, with large palatal plates, and others. In
the inferior tertiary formations, the London clay, the calcaire gros-
sier of Paris, and Monte Bolca, a third at least of the species belong
to genera which exist no longer. The chalk has more than two
thirds of its species referrible to genera which have now entirely dis-
appeared. In it we already even see some of those singular forms
which prevail in the Jurassic series. But as a whole the fish of the
chalk recall more forcibly the general character of the tertiary fish
than that of the species of the Jurassic series.

If we paid attention only to fossil fish in the grouping of geolo-
gical formations on a large scale, the author thinks it would be more
natural to associate the cretaceous with the tertiary strata than to
place the former among the secondary groups. Below the chalk
there is not a single genus which contains recent species, and even
those of the chalk which have them contain a much greater propor-
tion of species which are only known as fossil. The oolitic series,
to the lias inclusive, forms a very natural and well defined-group,
in which also must be included the Wealden, in which Mr. Agassiz
states he has not found a single species referrible even to the genera
of the chalk. Henceforth, the two orders which prevail in the pre-
sent creation are found no more; whilst those which are in a small
minority in our days, appear suddenly in great numbers. Of the
Ganoidians, those genera which have a symmetrical caudal fin are
found here, and among the Placoidians those above all predominate
which have their teeth furrowed on both the external and internal
surface, and have large thorny rays. For it is now certain that
those great rays which have been called Ichthyodorulites, belong
neither to Silures nor Balistas, but are the rays of the dorsal fin of
the great Squaloids, whose teeth are found in the same strata.

On leaving the lias to come to the inferior formations, we observe
a great difference in the form of the posterior extremity of the body
in the Ganoidians. All have their vertebral column prolonged at
its extremity into a single lobe, which reaches to the end of the
caudal fin, and this peculiarity extends even to the most ancient
fish. Another observation worthy of attention is, that we do not
find fish decidedly carnivorous before the carboniferous series; that
is to say, fish provided with large conical and pointed teeth. The
other fish of the secondary series before the chalk appear to have
been omnivorous, their teeth being either rounded, or in obtuse
cones, or like a brush.

The discovery of coprolites containing very perfect scales offish
which had been eaten, permits us to recognise the organized beings
which formed the food of many ancient fish ; even the intestines,
and in some fossil fish of the chalk the whole stomach is preserved,
with its different membranes. In a great number offish from Shep-

462 Review : — Transactions of the Entomological Society.

pey, the chalk, and the oolite series, the capsule of the bulb of the
eye is still uninjured ; and in many species from Monte Bolca, Solen-
hofen, and the lias, we see distinctly all the little blades which
form the branchiae.

It is in the series of deposits below the lias that we begin to find
the largest of those enormous sauroid fish whose osteology recalls,
in many respects, the skeletons of saurians, both by the closer su-
tures of the bones of the skull, their large conical teeth, striated
longitudinally, and the manner in which the spinous processes are
articulated with the body of the vertebra? and the ribs at the ex-
tremity of the spinous processes.

The small number offish yet known in the transition formations
does not as yet permit the author to assign to them a peculiar charac-
ter, nor has he discovered in the fossil fish of strata below the green-
sand any differences corresponding with those now observed be-
tween marine and freshwater fish, so that he cannot, on ichthyo-
logical data, decide on the freshwater or marine origin of the an-
cient groups.

This paper is accompanied by Tables of the fossil fish of different
formations.

LXVI. Reviews, and Notices respecting New Books.

The Transactions of the Entomological Society of London. Vol. I.
Part I. With Seven Plates. 8vo. pp. 108.

WE are here presented with the first publication of a Society es-
tablished for the cultivation of a department of Natural History
which is fast gaining ground amongst us. It would be out of place
here to enlarge upon the interest and importance of the study of that
vast portion of animated nature known by the general term Insects ;
suffice it to say that this First Part of the Transactions of the Ento-
mological Society, in the prospectus of its Prize Essays, as well as in
several of the Communications, gives evidence of the practical uti-
lity to which the attention of the Society is directed ; and which, if
persevered in, cannot fail of establishing it on the firmest basis.

Passing over the Introduction, which mentions the origin of the
Society, and comments, perhaps in rather too severe terms, upon
the opposition which has been raised against the publication of its
Transactions, we are presented with a series of thirteen memoirs,
which from their varied character cannot fail to interest not only the
professed entomologist but also the general reader. Of the latter
character may be mentioned Mr. Spence's '* Observations on a
Mode practised in Italy of excluding the common House-fly from
Apartments ; " Mr. W. B. Spence's Remarks on a passage in He-
rodotus, relative to the attacks of Gnats, which has greatly per-
plexed the Commentators ; Mr. W. E. Shuckard's Observations
upon the habits of the indigenous Sand Wasps ; valuable not only
on account of the facts narrated, but from the correction thereby af-
forded of a theory recently proposed relative to these insects by M.
le Comte de Saint Fargeau ; Mr. W. W. Saunders's Paper upon
the habits of some Indian Insects; and Mr. Lewis's " Explanation

Intelligence and Miscellaneous Articles. 463

'to

of the sudden Appearance of the Web-spinning Blight of the Apple,
Hawthorn, &c." Among those of a morepurely scientific character may
be mentioned: the Rev. F.W. Hope's Descriptions of some hitherto
uncharacterized exotic Coleoptera, chiefly from New Holland ; Mr.
Waterhouse's Descriptions of the Larvae and Pupae of various Species
of Beetles ; Mr. Lewis's Descriptions of some new Genera of Bri-
tish Homoptera; Mr. G. R. Gray's Descriptions of several Species
of Australian Phasmata, &c. ; whilst others are of a mixed nature,
as Mr. Christy's Remarks on a Species of Calandra occurring in the
Stones of Tamarinds j Mr. Waterhouse's Account of Raphidia ophi-
opsis ; and Mr. Westwood's Description of the Nest of a gregarious
Species of Butterfly from Mexico. The part concludes with the
Journal of Proceedings, (a judicious addition, we think, and almost
new in the " Transactions" of British societies,) By-Laws, and List
of Members. The plates are beautifully executed, each containing
a great amount or variety of subjects.

LXV1I. Intelligence and Miscellaneous Articles.

DISCOVERY OF SAURIAN BONES IN THE MAGNESIAN CONGLOME-
RATE NEAR BRISTOL.

ALTHOUGH some of the earliest noticed Saurian remains were
the fossil Monitors of Thuringia, discovered in the Continental
equivalents of our magnesian limestone, — characterized by the same
testacea and fishes which Mr. Sedgwick has so fully described in our
own corresponding formations in the North of England, — it does not
appear that Saurian remains have been until now detected in this
geological site in our own series. Recently, however, a quarry of
the magnesian conglomerate, resting on the highly inclined strata of
carboniferous limestone, at Durdham Down, near Bristol, has af-
forded some Saurian vertebrae, ribs, femora, and phalanges, together
with claws, the latter of considerable proportional size : a coracoid
bone has also been found, approaching very nearly to that of the
Megalosaurus. The general character of the bones seems inter-
mediate between those of this genus and the crocodile. Dr. Riley,
who submitted the specimens hitherto discovered, to the Literary and
Philosophical Society of the Bristol Institution, is understood to be
preparing a detailed account of this interesting discovery for the
Geological Society.

The only Saurian remain hitherto found in this island in a site
approaching to this, was a fragment of a lower jaw apparently of a
Gavial discovered in the lower beds of the new red sandstone at Guy's
Cliff, Warwickshire. This fact was communicated by Mr. Conybeare
to Mr. Parkinson, and is noticed in the abridged work of the latter
on Organic Remains.

EXPERIMENTS ON THE ACTIVE PRINCIPLE OF SARSAPARILLA.
BY M. POGG1ALE.

M. Palotta, in 1824, announced an active principle in sarsaparilla
which he called parilline. Soon afterwards M. Folchi thought he
had discovered a new principle which he named smilacine. In the

464? Intelligence and Miscellaneous Articles.

■5

year 1831, M..Thubeuf stated that he had extracted a new substance
from sarsaparilla to which he gave the name of salseparine, and last-
ly, M. Batka, a German chemist, towards the end of the year 1833,
described an acid which he called parillinic acid. The question to
be resolved is, are these four substances four new bodies, or are they
merely one and the same principle obtained by different methods ?

A considerable quantity of parilline, smilacine, salseparine, and
parillinic acid was prepared ; following the process of M. Palotta,
very fine parilline was obtained, but the smilacine of M. Folchi was
not so easily prepared ; and he was undoubtedly mistaken in saying
that an appreciable quantity of smilacine might be obtained by ma-
cerating in water one ounce of the pith of sarsaparilla, treating the
solution with animal charcoal, and evaporating. It is, according to
M. Poggiale, impossible to extract from one ounce of the pith, by
means of water, the smallest portion of smilacine; the method
adopted by him was to treat the pith with alcohol and charcoal,
and the product possessed all the properties of parilline. Although
M. Thubeuf did not publish his mode of preparing salseparine, the
process was known to be that of making an alcoholic solution of sar-
saparilla, treating this with animal charcoal and crystallizing it ■ the
substance obtained possessed no properties differing from those of
parilline, as will presently be proved. Parillinic acid was also pre-
pared according to the directions of M. Batka.

These four substances are all white, inodorous, and when de-
prived of water, without taste. They are very bitter and nauseous
to the taste when dissolved in water or alcohol. They are heavier
than water; insoluble in cold, but slightly soluble in boiling, water;
very soluble in boiling alcohol, less so in cold; boiling aether dissolves
them all; the volatile oils take them up perfectly; they are less so-
luble in the fixed oils; they exert but slight action on turmeric pa-
per, none on litmus, and turn the syrup of violets green. The}' are
all decomposed in the same manner by heat, leaving an extremely
light charcoal possessing a metallic lustre. They all crystallize in
radiated acicular crystals when an alcoholic solution is carefully
evaporated.

The substance obtained by M. Batka is not an acid ; it is true it
reddens litmus paper, but this property is owing to a small quantity
of muriatic acid which it retains: if, however, this supposed acid is
washed seven or eight times with water, it will no longer exert any
action on the litmus paper. M. Poggiale attaches the greatest im-
portance to the analyses of these substances, which he states he has
performed with the greatest care.

Analysis of Salseparine.

Salseparine, dried at 248° Fahr. in a stove and analysed by M.
Liebig's apparatus, gave the following results.

1st.

2nd.

3rd.

Carbon

62-53

62-39

62-70

Hydrogen

8-80

859

8-28

Oxygen

28-67

26-02

29-02

100- 97- 100-

Intelligence and Miscellaneous Articles. 465

The Analysis of Parilline by the same apparatus gives

1st. 2nd. 3rd.

Carbon 62-22 62'99 6207

Hydrogen 8'96 876 8'40

Oxygen 28*82 28'25 29\53

100-

100-

100-

Analysis of

Parillinic Acid.

1st.

2nd.

3rd.

Carbon

62-98

6238

62-76

Hydrogen

8-88

8-96

8-63

Oxygen

28-14

28-66

2861

100-

100-

100-

Analysis oj Smilacine.

1st.

2nd.

3rd.

Carbon

62-83

62-43

62-08

Hydrogen

8-41

8-68

8-78

Oxygen

28-76

28-89

29-14

100- 100- 100-

Which experiments denote the atom of salseparine to consist of
carbon 8 atoms, hydrogen 15 atoms, and oxygen 3 atoms. From
these facts M Poggiale arrives at the following conclusions: That
M.Palotta discovered the active principle of sarsaparilla; that smila-
cine, parillinic acid, and salseparine are identical with the parilline of
M. Palotta, but procured by different methods ; that the properties
of these four substances are the same ; and that the pith of sarsapa-
rilla as well as the bark contains salseparine. — Journal de Pharmacies
October 1834.

PREPARATION OF CYANURET OF POTASSIUM.

According to M. Robiquet, when ferrocyanuret of potassium is
calcined in a retort, there are formed cyanuret of potassium and
quadricarburet of iron ; and when the retort is carefully broken, a
certain quantity of perfectly pure fused cyanuret of potassium is ob-
tained, which is quite fit for medicinal use. — Ibid. Sept. 1834.

COMPOSITION OF L1THIC ACID.

M. Liebig observes that lithic acid is unquestionably one of the
most remarkable organic acids, both with respect to its composition
and the effects which it produces in certain diseases, such as gra-
vel, urinary calculi, and gouty concretions.

The composition of this acid has been variously stated, and no
two analyses agree : these differences arise from the circumstance
of chemists not having directly determined the proportion of carbon
which the acid contains, and are consequently deprived of the con-
troul in determining the azote which M. Liebig conceives that his
apparatus admits of.

Third Series. Vol. 5. No. 30. Dec. 1834. 3 O

66 Intelligence and Miscellaneous Articles.

The results of the analysis were

By experiment. By calculation. Atomically.

Carbon 36-083 36*11 5 atoms. . 382-185

Azote 33361 33-36 4 364'07'2

Hydrogen 2-44-1 2-34 4- 24959

Oxygen 28-126 27*19 3 300-000

100-011 99- 1071-216

According to this atomic weight, the compounds of lithic acid with
bases which are at present known, are supersalts. — Ibid., p. 571.

GEOLOGICAL SURVEY OF THE UNITED STATES.

We announce with great satisfaction a most important act of
legislation by the Congress of the United States, the authorization
of a geological survey of that fine country, so rich in minerals and
geological phaenomena. It gives us pleasure also to add that Pre-
sident Jackson has committed the execution of this arduous under-
taking to Mr. Featherstonhaugh, one of the members of the Geolo-
gical Society of London, who has acquired deserved reputation as
a practical and ardent geologist. This gentleman has been many
years a resident of the United States, and it is of him that Mr. Cony-
beare, in his celebrated Report*, says, — " Mr. Featherstonhaugh, a
geologist eminently qualified, from his intimate acquaintance with
European formations, to advance those comparative views which
demand the principal attention in our science."

We cannoc but look with unmixed admiration upon the steadi-
ness with which all the great interests of the United States are pur-
sued: the States have wisely concurred in a great act of legislation
that cannot but redound to the best interests of their country, and the
substantial advancement of natural science. It is an act that Europe
will admire, and we hope imitate, and that will ever reflect great
honour upon the administration of the present distinguished chief
magistrate of the United States.

Private letters state, that Mr. Featherstonhaugh left Washington
in July, for the country west of the Mississippi, to examine the
high lands in the Arkansa territory, called the Ozark and Mazerne
Mountains. These are separated, to the distance of about five hun-
dred miles, by the gorge of the Mississippi valley, from the high
lands east of the Mississippi, which constitute the Alleghany
ranges ; and their geological structure has not yet been examined.

By the kindness of Dr. Buckland we are enabled to annex some
extracts from a letter addressed to that eminent Geologist by our
friend R. C. Taylor, Esq., F.G.S., dated some time before the Act
of Congress, but containing some interesting particulars of the
Geology of the United States.

" I am happy to report that the spirit of geological inquiry is fast
spreading in this state. A committee is now sitting in the House of
Representatives on the subject of a Geological Survey of the whole

* See our last volume, p. 42/.

Intelligence and Miscellaneous Articles. 467

'to

of Pennsylvania, at the expense of the state, for the purpose of con-
structing a geological map, and of exhibiting and reporting upon all
its mineral products and resources. I find my name is nominated
to this duty, in conjunction with two gentlemen; one of them, Col.
Long, of the U.S. Topographical Engineers, the other, Mr. Tanner,
a gentleman connected with the publishing Topographical depart-
ment. The assent of the Government is fully expected to this im-
portant proposition, and if so, it will go into operation very shortly.

** This is a very interesting region, as I hope hereafter to show.
Mineralogically it has nothing to boast, except its vast deposits of
haematitic iron ore, which is dug out exactly in the same manner as
gravel out of the gravel pits in England. These accumulations
always occur in the limestone valleys. The average yield of iron
being about fifty per cent., numerous iron-works are established in
these valleys. I say valleys because they are numerous, and parallel
to the main Alleghany ridge, and are separated by long steep ridges
700 to 900 feet high, of red sandstone, stretching, I believe, hun-
dreds of miles from south to north. It will give you an idea of the
enormous thickness of these formations when I mention that nearly
the entire series of beds are upon their edges, sometimes vertical,
and very rarely less than 45°, rhe inclination being sometimes to
and sometimes from the Alleghanies, while all westward of that chain
(for many miles beyond the Ohio,) is horizontal, or slightly curving,
and comprises the great Central Coal Field of this continent. I have
scarcely seen anything in all this vast development of strata under
the coal which does not contain the mountain limestone fossils, such
as Producta, Spirifers, &c, the former in astonishing profusion, and
all having specific differences from the English.

" There is now a project before the Congress at Washington,
submitted by the Secretary at War, and closely watched by Mr.
Featherstonhaugh ; no less than a geological survey of the entire
continent, under the government of the United States, to be con-
nected with the Engineer Department. For this purpose, or rather
in connexion with it, a Professorship of Geology and Mineralogy is
recommended at West Point Military Academy, for the initiation of
the cadets, who in time will he dispersed all over the Union, and
will carry their industry and zeal into a wide and useful field. Should
this plan be adopted, the Professorship will be offered to Mr. F., and
my aid has also been asked in cooperation in this grand undertaking.
1 should be proud to be an associate in such a gigantic project ; and
here the observations I made previously, with regard to assimilating
to your English map9, &c, are applicable, with even greater force*.
It will afford a grand opportunity for forming a national museum in
the capital.

" I fear there is little chance of discovering formations in this
country less ancient than the coal, unless it be in those accumula-
tions in Maryland, containing shells resembling those of the Lon-
don clay and my old acquaintance the Norfolk crag."

* Mr. Taylor here alludes, we presume, to the propriety of preserving
uniformity of colouring between the geological maps constructed in this
country and in America. — Edit.

30 2

«5

la
E

London. — Oct. 1. Hazy : fine. 2. Dense fog:
very fine : foggy. 3 — 6. Dense fog in the morn-
ings : very fine. 7, 8. Very fine. 9—11. Cloudy :
very fine. 12. Slight fog : fine. 13. Foggy : very
fine. 14. Overcast: slight shower. 15. Fine.

16. Overcast: rain: clear and windy at night.

17. Clear and windy : rain. 18. Clear and windy.

19. Slight fdg: drizzly. 20. Fine: rain.
21. Cloudy and cold. 22. Cloudy and windy.
23. Stormy with rain. 24,25. Clear, cold, and
dry. 26. Fine, but cold. 27. Hazy. 28. Foggy.
29. Dry haze. 30. Hazy : fine : foggy. 31. Fine.
The weather in September was noticed as having
been particularly fine ; in this month, the continu-
ation of such renders it still more remarkable. The
temperature was often high for this period of the
season j on the 5th the thermometer stood at 80°
in the shade.

Bost on.— .October 1. Cloudy. 2 — 8. Fine.
9. Cloudy. 10 — 13. Fine, "l 4. Cloudy : rain p.m.
15, 16. Cloudy. 17, 18. Stormy. 19. Cloudy.

20. Cloudy: rain a.m. and p.m. 21, 22. Stormy.
23. Stormy: rain early a.m. 24. Stormy : ice this
morning : rain p.m. 25. Stormy. 26. Fine.
27, 28. Cloudy. 29. Fine. 30. Cloudy.
31. Stormy.

^

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INDEX to VOL V.

Achromatic lens, negative, its

application to telescopes, &c, 452.

Acids: — muriatic acid in fluor spars,
78; chrenic, 238; apochrenic, 238;
valerianic, 396 ; tartaric and pyro-
tartaric, 397 ; oxalic, 445; lithic, 465.

Addams ( R.) on a peculiar optical pliaj-
nomenon, 373.

JEther, hydrocyanic, 397.

Agassiz (Dr.) on the growth and bi-
lateral symmetry of Echinndermata,
369; on the classification of fish,
459.

Air, its action on lead, 81.

Airy (Prof.) on the solar eclipse, July
16,1833,305; on the position of the
ecliptic, 307.

Anions, 429.

Apochrenic acid, in the mineral waters
of Porta, 238.

Araneides, characters of some unde-
scribed species of, 50.

Artesian wells, temperature of, 237.

Astronomical Society, 300.

Atomic constitution of elastic fluids,
33.

Babbage (C.) on the Temple of Se-
rapis at Pozzuoli, 213; views re-
specting geological cycles, 215.

Barlow (P.) on the application of the
negative achromatic lens to tele-
scopes, &c, 452.

Barlow ( P. W.) on the motion of steam-
vessels, 453.

Barton (J.) on the influence of high
and low prices on the rate of mor-
tality, 278.

Beke (C. T.), reply to his papers on
gopher- wood, and former extension
of Persian Gulf, 244.

Bell (Sir C.) on the functions of the
brain, 451.

Bell (T.), description of Cyclemys, a
type of a new genus of the freshwater
tortoise, 143.

Bennett (G.) on the habits of the King
Penguin, 231.

Berzelius (M.), discovery of chrenic
and apochrenic acids in the mineral
waters of Porta, 238.

Biela's comet, 301, 310.

Blackburn (C.) on the modern tele-
graphs, 241, 365.

Blackwall (J.) on some undescribed

species of Araneidec, 50.
Botany : — deviations from the ordinary

structure in Telopea speciosissima,10 ;
female flower and fruit of Rqfflesia,
70; structure of Hydnora, 70; in-
ternal structure of plants, 112, 181,
284 ; action of tannin on the roots
of plants, 157.

Boussingault on suboxide of lead and
protoxide of tin, 79; on the sup-
posed compound of hydrogen and
platina, 155.

Brain, analysis of the, 392; on the
functions of the, 451.

Breithaupt's Mineralogy, notice of,
237.

British Association, outline of pro-
ceedings of the Meeting at Edin-
burgh, 386.

Broderip (W. J.), descriptions of new
species of Calyptr aides, 72, 232 ; de-
scription of a new genus of Gastero-
poda, 312.

Brown (R.) on the female flower and
fruit of Rafflesia, 70.

Bryce (J.) on the minerals of the north
of Ireland, 196.

Caloric, electricity, and ponderable bo-
dies,remarkableanalogybetween,110.

Calyptr addce, anatomy of the, 72 ; new
species of, 72, 232.

Camphor, rotary motion of, 1 51.

Carter (W. G.) on the gopher- wood of
Scripture, and former extension of
the Persian Gulf, 244.

Cations, 429.

Chrenic acid in the mineral waters of
Porta, 238.

Clinometer, Henslow's, improvement
in, 159.

Coal-fields, English, on the future ex-
tension of, 44.

Comet, Biela's, 301, 310; Encke's,
304 ; Halley's, 284.

Connel (A.) analysis of Levyne, 40.

Conybeare (Rev. W. D.) on the future
extension of the English coal-fields,
44.

Cooper (P.) on the colorific rays of
white light, 453.

Crystallization of kalium, 399.

Crystals of snow, remarkable, 318.

Cuckoo, remarks on the, 149.

Cyanogen, new radical analogous to, 78.

Davy (Dr.) on the recent volcano in
the Mediterranean, 453.

Dawes (Rev. W. R.), micrometrical
measures of double stars, 302.

470

INDEX.

Deluge, Greek traditions of the, 25.

Dcebereiner on some new combina-
tions of platina, 150.

Don (D.) on deviations from the ordi-
nary structure in Telopea sjieciocis-
sinui, 70.

Echidna, some remarks on the, 146.

Echinoderniata, growth and bilateral
symmetry of, 369.

Egerton (Sir P. G.) on the ossiferous
caves of the Harts and Franconia,
296.

Electric storm, description of a, 418.

Electric action, on, 6.

Electrical kite, caution to experiment-
ers with, 317.

Electricity, Prof. Faraday's researches
in, 161, 252, 334, 424, 456.

Electricity, caloric, and ponderable
bodies, analogy between, 1 10.

Electricity of tourmaline, 133.

Encke's comet, 304.

Entomological Society, 236.

Equations, interesting case in, 188.

Eye, on the spectra of the, 192.

Fairholme (G.) on the Falls of Nia-
gara, 11.

Faraday (Prof.), researches in electri-
city, 161, 252, 334, 424, 456* ; on the
magneto-electric spark and shock,
349, 444.

Fish, on the classification of, 459.

Fluids, elastic, atomic constitution of,
33.

Fluor spars, muriatic acid in, 78.

Forbes (Prof.) on the electricity of
tourmaline, 133.

Fossils collected in Cutch, 217; fossil
wax, 316; fossil fish, 461.

Fox (R. W.) on magnetic attraction
and repulsion, 1 ; on electrical ac-
tion, 6.

Gasteropoda, new genus of, 312.

Gay Lussac on the purification of car-
bonate of soda, 316.

Geological Society, 53, 211, 292, 459;
anniversary address, 53.

Geology: — on the Falls of Niagara,
1 1 ; on the future extension of the
English coal-fields, 44 ; Mr. Green-
ough's Address to the Geological
Society, 53; discovery of bones of
the iguanodon, 77 ; on the stratifi-
cation of Derbyshire, 121 ; on the
quantity of solid matter suspended
in the water of the Rhine, 21 1 ; geo-
logy of the neighbourhood of Read-
ing, 212 ; on the Temple of Serapis
at Pozzuoli, 213; views respecting
geological cycles, 215; variations of
temperature in a thermal spring at
Mallow, 216 ; on the delta of Kan-
der, 216; fossils collected in Cutch,

217 ; on the gravel and alluvial de-
posits of Hereford, Salop and Wor-
cester, 217 ; notice of the coast from
Whitstable to the North Foreland,
219; on the ravines, passes and frac-
tures in the Mendip Hills, 220; on
the tertiary formation of Murcia,
220; geology of the Bermudas, 222;
on the organic remains in the lias
series of Yorkshire, 222; on the
loamy deposit in the valley of the
Rhine, 223 ; on certain trap rocks
in Salop, &c, 225, 292; observations
on wells dug at Diss and Hampstead,
295 ; on the ossiferous caves of the
Hartz and Franconia, 296 ; on the
occurrence of freshwater shells be-
neath the gravel, 297 ; on subterra-
nean temperature, 446; geological
distribution of fossil fish, 461 ; sau-
rian bones found in the magnesian
conglomerate, 463 ; geological sur-
vey of the United States, 466.
Glass, action of high pressure steam

on, 297.
Goose, Sandwich Island, 233.
Gopher-wood of Scripture, on the, 244.
Gbttingen, new magnetical observatory

at, 344.
Graham (Prof.) on phosphuretted hy-
drogen, 401.
Gray ( Mr.), description of the new ge-
nus Ganymeda, 73.
Greenough (G. B.), address to the

Geological Society, 53.
Griffiths (Mrs.) on the spectra of the

eye and seat of vision, 1 92.
Halley's comet, on the reappearance

of, 284.
Harding (Prof.), notice of, 319.
Hare (Dr.), apparatus for freezing

water, 377.
Hausmann (Prof.) on Mr. Whewell's
account of his mineralogical works,
158.
Henry (Dr. W. C) on the atomic con-
stitution of elastic fluids, 33; reply of
Dr. Prout to, 132.
Henslow's clinometer, improvement

in, 159.
Herschel (Sir J. F. VV.), micrometrical

measures of double stars, 302.
Hogg (J.) on the influence of the cli-
mateof Naples on vegetation, 46, 102.
Honey of Trebizond, 313.
Hopkins (W.) on Mr. Farey's account
of the stratification of the limestone
districts of Derbyshire, 121.
Horner ( W. G.) on an interesting case

in equations, 188.
Horner (L.) on the quantity of solid
matter suspended in the water of the
Rhine, 211.

INDEX.

471

Hydrogen, phosphuretted, 401.

Hydrogen and platina, compound of,
155.

Ions, table of, 429.

Iguanodon, discovery of bones of the,
77,

Iridium, preparation of, 314.

Ivory (J.) on the equilibrium of fluids,
454.

Jacobson (M.) on the physical and
therapeutic properties of chroinate
of potash, 238.

K. on some curious facts respecting
vision, 375.

Kalium, crystallization of, 399.

Keith (Rev. P.) on the internal struc-
ture of plants, 112, 181, 284; on
phytological errors and admonitions,
205.

Kenrick ( Rev. J.) on the Greek tra-
ditions of the deluge, 25.

Lantern-fly, observations on the, 144.

Lead, brown phosphate of, 78 ; sub-
oxide of, 79 ; on the action of water
and air on, 81 ; on its electric rela-
tion to iron, &c, 92.

Levyne, analysis of, 40.

Lithic acid, composition of, 465.

Light, experiments on, 321 ; applica-
tion of photometry to the undulatory
theory of, 439.

Linnaean Society, 70, 298.

Lyell (C.) on the loamy deposit in the
valley of the Rhine, 223.

Lyon (D.) on magnetic substances,
415.

Magnesia, borates of, 156.

Magnetic attraction and repulsion, 1.

Magnetic substances, on, 415.

Magnetical Observatory at Gottingen,
344.

Magneto-electric spark and shock, 349,
444.

Magneto -electrical experiments, 376.

Manufactures of the ancients, 355.

Margaron, 153.

Meteorological table : for May, 80 ;
for June, 160; for July, 239; for
August, 320 ; for September, 400 ;
for November, 468.

Mortality, influence of high and low
prices on, 278.

Moseley (Prof.) on the principle of
least pressure, 95 ; Mr. Horner's con-
siderations relative to, 188.

Mummy cloth of Egypt, on the, 355.

Mural circles, Greenwich, 305; Cape
of Good Hope, 309.

Murchison (R. I.) on the gravel and
alluvial deposits of Hereford, Salop,
and Worcester, 217 ; on certain trap
rocks in Salop, &c, 225, 292.

Muriatic acid in fluor spars, 78.

Nelson (Lieut.) on the geology of the

Bermudas, 222.
Niagara, on the Falls of, 11.
Nixon (J.) on the tides in the Bay of

Morecambe, 264.
Nordenskiold on Phenakite, 102.
Oleon, 153.
Optical phsenomenon, peculiar, 373.

Ornithorhyiichus paradoxus, on the
young of, 235.

Osmiridium, on, 101.

Osmium, preparation of, 314.

Owen (R.) anatomy of the Calyptreridx,
72 ; on the structure of the heart of
the Perennibranchiate Amphibia, 150;
on the young of the Ornithorhynchus
paradoxus, 235.

Oxalic acid, action of chloride of so-
dium upon, 445.

Parabolic curves, the arcs of, 455.

Parallelogram of forces, demonstration
of the, 39.

Parilline and parillinic acid, analysis
of, 465.

Payen (M.) on the action of tannin, &c.
on the roots of plants, 157.

Penguins, on the habits of, 231.

Persian Gulf, former extent of, 244.

Phenakite, a new mineral, 102.

Phillips (J.) on subterranean tempe-
rature, 446.

Phosphuretted hydrogen, on, 401.

Photometry, on, 327 ; its application to
the undulatory theory of light, 439.

Phytological errors and admonitions,
205.

Plants, on the internal structure of,
112, 181, 284; action of tannin on
the roots of, 157.

Platina, on some new combinations of,
150; discovery of in France, 158.

Platina and hydrogen, compound of,
155.

Poggiale (M.) on the active principle
of sarsaparilla, 463.

Polyspherite, 78.

Potash, chromate of, physical and the-
rapeutic properties of, 238.

Potassium, cyanuret of, 465.

Pratt (J. H.), demonstration of the pa-
rallelogram of forces, 39 ; improve-
ment in Henslow's clinometer, 159.

Protoxide of tin, 79.

Prout (Dr.), reply to Dr. W. C. Hen-
ry, 132:

Pyrotartaric acid, distillation of, 397.

Rees (G. O.) on the existence of tita-
nium in organic matter, 398.

Reviews : — Dr. Daubeny's Inaugural
Lecture on the study of Botany, 75 ;
Transactions of the Entomological
Society, 462.

Richardson (W.), notice of the coast

472

INDEX.

from Whitstable to the north Fore-
land, 219.

Rofe (J.) on the geology of the neigh-
bourhood of Reading, 212.

Rose (G.) on osmiridium from the
Ural, 101.

Rotary motion of camphor, 152.

Royal Society, 451.

Royal Institution, 74.

Salseparine, analysis of, 464.

Sarsaparilla, on the active principle of,
463.

Saurian bones in the magnesian con-
glomerate, 463.

Say's instrument for taking specific
gravities, improvement in, 203.

Shells, 144, 145, 148, 300, 312, 379,
380, 382.

Silvertop (C.) on the tertiary formation
of Murcia, 220.

Smilacine, analysis of, 465.

Societies, learned, proceedings of: —
Royal Society, 451 ; Linnaean, 70,
298 ; Geological, 53, 21 1, 292, 459;
Royal Astronomical, 300; Zoologi-
cal, 72, 143, 230, 31 1, 379 ; Royal
Institution, 74; Entomological, 236;
British Association, 386.

Soda, carbonate of, its purification, 316.

Sodium, chloride of, action of oxalic
acid upon, 445.

Solar eclipse of July 16, 1833,305,311.

Specific gravities, improvement in Say's
instrument for measuring, 203.

Stars, double, micrometrical measures
of, 302.

Steam-vessels, on the motion of, 453.

Stearon, 153.

Sturgeon (W.), caution to experi-
menters with the electrical kite, 317 ;
magneto-electrical experiments, 376;
description of a thunder-storm, 418.

Suboxide of lead, 79.

Sulphuric acid, apparatus for freezing
water by the aid of, 377.

Talbot ( H. F.), experiments on light,

321.
Tannin, its action on the roots of

plants, 157.
Talbot (H. F.) on the arcs of certain

parabolic curves, 455.
Tartaric acid, distillation of, 397.
Telegraphs, modern, on, 241, 365.
Telescopes, application of the negative
achromatic lens to, 452.

END

PRINTED BY RICHARD

Temperature, subterranean, 446.

Thermal spring at Mallow, variations
of temperature in, 216.

Thompson (W.) on some crystals of
snow, 318.

Thomson (J.) on the mummy cloth of
Egypt, 355.

Thunder-storm, description of a, 418.

Tides in the Bay of Morecambe, 264.

Tin, protoxide of, 79.

Titanium in organic matter, 398.

Tortoise, freshwater, type of a new
genus of, 143.

Tourmaline, on the electricity of, 133.

Trigonometrical functions, 198.

Turner (Dr.) on the action of high
pressure steam on glass, 297.

Undulatory theory of light, application
of photometry to, 439.

United States, geological survey of,
466.

Valerianic and its salts, 396.

Vegetation, comparative influence of
the climate of Naples on, 46, 102.

Vision, on, 192; some curious facts
respecting, 375.

W. H. M., improvement in Say's in-
strument for taking specific gravi-
ties, 203.

Wax, fossil, 316.

Water, its action on lead, 81 ; appa-
ratus for freezing, 377.

West (W.) on a remarkable analogy
between ponderable bodies and ca-
loric and electricity, 1 10.

Wheeler (J. H.) on the application of
photometry to the undulatory theory
of light, 439.

Williams (Rev. D.) on the ravines,
passes, and fractures in the Mendip
Hills, 220.

Williamson (W.) on the organic re-
mains in the lias series of Yorkshire,
222.
Wohler on borates of magnesia, 156.
Wood (A. T.) on the action of oxalic

acid upon chloride of sodium, 445.
Yorke (Capt. P.), experiments on the
action of water and air on lead, 81 .
Young (J. R.) on certain trigonome-
trical functions, 198.
Zoological Society, 72, 143, 230, 311,
379.

VOLUME.

ON COURT, FLEET BTREE I

1834.

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