Full text of "Report of the British Association for the Advancement of Science"

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REPORT

NINTH MEETING

BRITISH ASSOCIATION

ADVANCEMENT OF SCIENCE;

HELD AT BIRMINGHAM IN AUGUST 1839.

LONDON:

JOHN MURRAY, ALBEMARLE STREET.
1840.

PRINTED BY RICHARD AND JOHN E. TAYLOR,
RED LION COURT, FLEET STREET.

CONTENTS.

Page

Objects and Rules of the Association v

Officers and Council viii

Places of Meeting and Officers from commencement ix

Table of Council from commencement x

Officers of Sectional Committees, and Corresponding Members xii

Treasurer's account xiv

Reports, Researches, and Desiderata xvi

Synopsis of Sums appropriated to Scientific Objects xxiv

Arrangements of the General Evening Meetings xxviii

Address of the President 1-68

REPORTS OF RESEARCHES IN SCIENCE.

Report on the present state of our knowledge of Refractive Indices
for the Standard Rays of the Solar Spectrum in different media.
By the Rev. Baden Powell, M.A., F.R.S., F.G.S., F.R. Ast. S.,
Savilian Professor of Geometry, Oxford 1

Report on the application of the sum assigned for Tide Calcula-
tions to Mr. Whewell, in a Letter from T. G. Bunt, Esq.,
Bristol 13

Notice of Determination of the Arc of Longitude between the Ob-
servatories of Armagh and Dublin, By the Rev. T. R. Robin-
son, D.D., &c 19

IV CONTENTS.

Page

Report of some Galvanic Experiments to determine the existence
or non-existence of Electrical Currents among stratified Rocks,
particularly those of the Mountain Limestone formation, consti-
tuting the Lead Measures of Alston Moor. By H. L. Pattin-
soN, Esq ^ 23

Report respecting the two series of Hourly Meteorological Ob-
servations kept in Scotland, at the expense of the British Asso-
ciation. By Sir David Brewster, K,H., LL.D., F.R.S. L. & E. 27

Report on the Subject of a series of Resolutions adopted by tbe
British Association at their Meeting in August, 1838, at New-
castle 31

Report on British Fossil Reptiles. By Richard Owen, Esq.,
F.R.S., F.G.S., &c 43

Report on the distribution of Pulmoniferous Mollusca in the
British Isles. By Edward Forbes, M.W.S., For. Sec. B.S.. . 127

Third Report on the Progress of the Hourly Meteorological Re-
gister at the Plymouth Dock-yard, Devonport. By W. Snow
Harris, Esq., F.R.S 149

OBJECTS AND RULES

THE ASSOCIATION.

OBJECTS.

The Association contemplates no interference with the ground
occupied by other Institutions. Its objects are, — To give a
stronger impulse and a more systematic direction to scientific
inquiry, — to promote the intercourse of those who cultivate Sci-
ence in different parts of the British Empire, with one another,
and with foreign philosophers, — to obtain a more general atten-
tion to the objects of Science, and a removal of any disadvan-
tages of a public kind which impede its progress.

RULES.

MEMBERS.

All Persons who have attended the first Meeting shall be
entitled to become Members of the Association, upon subscri-
bing an obligation to conform to its Rules.

The Fellows and Members of Chartered Literary and Philo-
sophical Societies publishing Transactions, in the British Em-
pire, shall be entitled, in like manner, to become Members of
the Association.

The Officers and Members of the Councils, or Managing
Committees, of Philosophical Institutions, shall be entitled, in
like manner, to become Members of the Association.

All Members of a Philosophical Institution recommended by
its Council or Managing Committee, shall be entitled, in like
manner, to become Members of the Association.

Persons not belonging to such Institutions shall be elected by
the General Committee or Council, to become Members of the
Association, subject to the approval of a General Meeting.

SUBSCRIPTIONS.

The amount of the Annual Subscription shall be One Pound,
to be paid in advance upon admission ; and the amount of the
composition in lieu thereof, Five Pounds.

VI RULES OF THE ASSOCIATION.

An admission fee of One Pound is required from all Members
elected as Annual Subscribers, after the Meeting of 1839, in
addition to their annual subscription of One Pound.

Members are entitled to receive copies of any volume of the
Transactions for two-thirds of the price at which it is sold to
the public ; or by one present payment of Five Pounds, as a
fixed Book Subscription, to receive a copy of all the volumes of
Transactions published after the date of such payment.

Subscriptions shall be received by the Treasurer or Secretaries.

If the annual subscription of any Member shall have been in
arrear for two years, and shall not be paid on proper notice, he
shall cease to be a member.

MEETINGS.

The Association shall meet annually, for one week, or longer.
The place of each Meeting shall be appointed by the General
Committee at the previous Meeting ; and the Arrangements
for it shall be entrusted to the Officers of the Association.

GENERAL COMMITTEE.

The General Committee shall sit during the week of the
Meeting, or longer, to transact the business of the Association.
It shall consist of the following persons : —

1. Presidents and Officers for the present and preceding years,
with authors of Reports in the Transactions of the Association.

2. Members who have communicated any Paper to a Philo-
sophical Society, which has been printed in its Transactions,
and which relates to such subjects as are taken into considera-
tion at the Sectional Meetings of the Association.

3. Office-bearers for the time being, or Delegates, altogether
not exceeding three in number, from any Philosophical Society
publishing Transactions.

4. Office-bearers for the time being, or Delegates, not ex-
ceeding three, from Philosophical Institutions established in
the place of Meeting, or in any place where the Association
has formerly met.

5. Foreigners and other individuals whose assistance is de-
sired, and who are specially nominated in writing for the meet-
ing of the year by the President and General Secretaries.

6. The Presidents, Vice-Presidents, and Secretaries of the
Sections are ex officio members of the General Committee for
the time being.

SECTIONAL COMMITTEES.

The General Committee shall appoint, at each Meeting,
Committees, consisting severally of the Members most conver-
sant with the several branches of Science, to advise together for
the advancement thereof.

RULES OF THE ASSOCIATION. VU

The Committees shall report what subjects of investigation
they would particularly recommend to be prosecuted during the
ensuing year, and brought under consideration at the next
Meeting.

The Committees shall recommend Reports on the state and
progress of particular Sciences, to be drawn up from time to
time by competent persons, for the information of the Annual
Meetings.

COMMITTEE OF RECOMMENDATIONS.

The General Committee shall appoint at each Meeting a Com-
mittee, which shall receive and consider the Recommendations
of the Sectional Committees, and report to the General Com-
mittee the measures which they would advise to be adopted for
the advancement of Science.

All Recommendations of Grants of Money, Requests for
Special Researches, and Reports on Scientific Subjects, shall be
submitted to the Committee of Recommendations, and not taken
into consideration by the General Committee, unless previously
recommended by the Committee of Recommendations.

LOCAL COMMITTEES.

Local Committees shall be formed by the Officers of the Asso-
ciation to assist in making arrangements for the Meetings.

Committees shall have the power of adding to their numbers
those Members of the Association whose assistance they may
desire.

OFFICERS.

A President, two or more Vice-Presidents, one or more Se-
cretaries, and a Treasurer, shall be annually appointed by the
General Committee.

COUNCIL.

In the intervals of the Meetings, the affairs of tlie Association
shall be managed by a Council appointed by the General Com-
mittee. The Council may also assemble for the despatch of
business during the week of the Meeting.

PAPERS AND COMMUNICATIONS.

The Author of any paper or communication shall be at liberty
to reserve his right of property therein.

ACCOUNTS.

The Accounts of the Association shall be audited annually, by
Auditors appointed by the Meeting.

REPORT 1839.

OFFICERS AND COUNCIL, 1839-40.

Trustees {'permanent.) — Francis Baily, Esq. R. I. Murchi-
son, Esq. John Taylor, Esq.

President.— The Rev. William Vernon Harcourt, F.R.S. G.S.

Vice-Presidents. — The Marquis of Northampton. The Earl
of Dartmouth. The Rev. T. R. Robinson, D.D. John Corrie,
Esq., deceased.

President elect. — The Most Noble the Marquis of Breadal-
bane.

Vice-Presidents elect. — The very Rev. Principal Macfarlane.
Major-Gen. Lord Greenock. Sir David Brewster. Sir Thos.
Macdougall Brisbane.

General Secretaries. — R. I. Murchison, Esq., F.R.S. Major
Sabine, F.R.S.

Assistant General Secretary. — John Phillips, Esq., F.R.S.
York.

Secretaries for Glasgow. — Rev. J. P. Nicol, LL.D. Andrew
Liddell, Esq. John Strang, Esq.

General Treasurer. — John Taylor, Esq., F.R.S., &c. 2, Duke
Street, Adelphi, London.

Treasurer to the Glasgow Meeting. — Charles Forbes, Esq.

Council. — Dr. Arnott. F. Baily, Esq. R. Brown, Esq.
Rev. Dr. Buckland. The Earl of Burlington. Professor Da-
niell. Dr. Daubeny. Professor T. Graham. J. E. Gray, Esq.
G. B. Greenough, Esq. Dr. Hodgkin. R. Hutton, Esq. M.P.
Dr. Lardner. Dr. R. Lee. Sir C. Lemon, Bart. J. W. Lub-
bock, Esq. C. Lyell, Esq. Professor Moseley. Professor
Owen. The Very Rev. Dr. Peacock. Professor Powell.
George Rennie, Esq. Lieut. -Col. Sykes. Captain Washing-
ton. Professor Wheatstone. Professor Whewell.

Secretary to the Council. — James Yates, Esq., F.R.S. 49,
Upper Bedford Place, London.

Local Treasurers. — Dr. Daubeny, Oxford. Professor Hens-
low, Cambridge. Dr. Orpen, Dublin. Charles Forbes, Esq.,
Edinburgh. William Gray, jun., Esq., York. William Sanders,
Esq., Bristol. Samuel Turner, Esq., Liverpool. Rev. John
James Tayler, Manchester. James Russell, Esq., Birmingham.
William Hutton, Esq., Newcastle-on-Tyne. Henry Wool-
combe, Esq., Plymouth.

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X REPORT 1839.

II. Table showing the Members of Council of the British Association
from its Commencement, in addition to Presidents, Vice-Presidents,
and Local Secretaries.

r Rev. Wm. Vernon Harcourt, F.R.S., &c. 1832—1836.

General Secretaries J ^^'^"'^^^ ^^'^J^' ^'^- ^"*^ '^'^^^- ^'^ ^^^•'^•

{general Secremries. J. ^ j Murchison, F.R.S., F.G.S 1836—1839.

LRev. G. Peacock, F.R.S., F.G.S., &c. ...1837, 1838.

General Treasurer. John Taylor, F.R.S., Treas. G.S., &c. ...1832—1839.

r Charles Babbage, F.R.SS.L. & E., &c. (Resigned.)

rr , r .N hR- I- Murchison, F.R.S., &c.

Trustees{^e,m^nent)J ^^^^ ^^^^^^^ ^^^^ ^;_

[Francis Baily, F.R.S.

Assistant General jprofessor PhiUips, F.R.S., &c 1832-1839.

oecretary. J r ' ?

Members of Council.

G. B. Airy, F.R.S. , Astronomer Royal 1834, 1835.

Neill Arnott, M.D 1838, 1839.

Francis Baily, V.P. and Treas. R.S 1837—1839.

George Bentham, F.L.S 1834, 1835.

Robert Brown, D.C.L., F.R.S 1832,1834,1835,1838,1839.

Sir David Brewster, F.R.S., &c 1832.

M. I. Brunei, F.R.S., &c .....1832.

Rev. Professor Buckland, D.D., F.R.S., &c. .1833, 1835, 1838, 1839.

The Earl of Burlington 1838, 1839.

Rev. T. Chalmers, D,D., Prof, of Divinity,

Edinburgh 1833.

Professor Clark, Cambridge 1838.

Professor Christie, F.R.S., &c 1833—1837.

William Clift, F.R.S., F.G.S 1832—1835.

John Corrie, F.R.S., &c 1832.

Professor Daniell, F.R.S 1836, 1839.

Dr. Daubeny 1838, 1839.

J. E. Drinkwater 1834, 1835.

The Earl FitzwilHam, D.C.L., F.R.S., &C....1833.

Professor Forbes, F.R.SS.L. & E., &c 1832.

Davies Gilbert, D.C.L., V.P.R.S., &c 1832.

Professor R. Graham, M.D., F.R.S.E 1837.

Professor Thomas Graham, F.R.S 1838, 1839.

John Edward Gray, F.R.S., F.L.S., &c 1837—1839.

Professor Green, F.R.S., F.G.S 1832.

G. B. Greenough, F.R.S., F.G.S 1832—1839.

Henry Hallam, F.R.S., F.S.A., &c 1836.

Sir William R. Hamilton, Astron. Royal of

Ireland 1832, 1833, 1836.

Rev. Prof Henslow, M.A., F.L.S., F.G.S.. ..1837.
Sir John F. W. Herschel, F.R.SS. L. &. E.,

F.R.A.S., F.G.S., &c 1832.

Thomas Hodgkin, M.D 1833—1837, 1839.

Prof Sir W. J. Hooker, LL.D., F.R.S., &c. .1832.

Rev. F. W. Hope, M.A., F.L.S 1837.

Robert Hutton, M.P., F.G.S., &c 1836, 1838, 1839.

Professor R. Jameson, F.R.SS. L. & E 1833.

MEMBERS OF COUNCIL. XI

Rev, Leonard Jenyns 1838.

Dr. R. Lee 1839.

Sir C. Lemon, Bart., M.P 1838, 1839.

Rev. Dr. Lardner 1838, 1839.

Professor Lindley, F.R.S., F.L.S., &c 1833, 1836.

Rev. Provost Lloyd, D.D 1832, 1833.

J. W. Lubbock, F.R.S., F.L.S., &c., Vice-

Chancellor of the University of Londonl 833— 1836, 1838, 1839.

Rev. Thomas Luby 1832.

Charles Lyell, jun.. Esq 1838, 1839.

William Sharp MacLeay, F.L.S 1837.

Professor Moseley 1839.

Patrick Neill, LL.D., F.R.S.E 1833.

Richard Owen, F.R.S., F.L.S 1836, 1838, 1839.

Rev. George Peacock, M.A., F.R.S., &c. ...1832, 1834, 1835, 1839.
Rev. Professor Powell, M.A., F.R.S., &c. ...1836, 1837, 1839.

J. C. Prichard, M.D., F.R.S., &c 1832.

George Rennie, F.R.S 1833—1835, 1839.

Sir John Rennie 1838.

Rev. Professor Ritchie, F.R.S 1833.

Sir John Robison, Sec. R.S.E 1832, 1836.

P. M. Roget, M.D., Sec. R.S., F.G.S., &c.... 1834— 1837.

Major Sabine 1838.

Rev. William Scoresby, B.D,, F.R.SS. L.&E.1832.
Lieut.-Col. W. H. Sykes, F.R.S., F.L.S., &c.l 837— 1839.

Rev. J. J. Tayler, B.A., Manchester 1832.

Professor Traill, M.D 1832, 1833.

N. A. Vigors, M.P., D.C.L., F.S.A., F.L.S.1832, 1836.

Captain Washington, R.N 1838, 1839.

Professor Wheatstone 1838, 1839.

Rev. W. Whewell 1838, 1839.

William Yarrell, F.L.S 1833—1836.

Secretaries to the f Edward Turner, M.D., F.R.SS. L. & E... 1832— 1836
Cotmcil. \ James Yates, F.R.S., F.L.S., F.G.S 1832—1839

REPORT 1839.

OFFICERS OF SECTIONAL COMMITTEES AT THE
BIRMINGHAM MEETING.

SECTION A. MATHEMATICAL AND PHYSICAL SCIENCE.

Pi'esident. — Rev. Professor Whewell, F.R.S.

Pice- Presidents. — Francis Baily, Esq., F.R.S. Professor
Forbes, F.R.S. Major Sabine, F.R.S.

Secretaries. — J. D. Chance, Esq. W. Snow Harris, Esq.,
F.R.S. Professor Stevelly.

SECTION B. CHEMISTRY AND MINERALOGY.

President. — Professor T. Graham, F.R.S.

Vice-Presidents. — Professor Johnston, F.R.S. Richard Phil-
lips, Esq. F.R.S.

Secretaries. — Golding Bird, M.D., F.L.S. J. B. Melson,
A.B., M.D.

SECTION C. — GEOLOGY AND PHYSICAL GEOGRAPHY.

President for Geology .—Rev . W. Buckland, D.D., F.R.S.,
Pres. G.S.

President for Physical Geography. — G. B. Greenough, Esq.
F.R.S.

Vice-Presidents.— Yl. T. De la Beche, Esq., F.R.S. Leonard
Horner, Esq., F.R.S. Charles Lyell, Esq., F.R.S.

Secretaries.— GQorge Lloyd, M.P., F.G.S. H. E. Strick-
land, Esq., F.G.S. Charles Darwin, Esq., F.R.S.

SECTION D. — ZOOLOGY AND BOTANY.

President. — Professor Owen, F.R.S.

Vice-Presidents.— ^5 . E. Gray, Esq., F.R.S. Dr. Graham,
F.R.S.E. Professor Daubeny, F.R.S.

Secretaries. — E. Forbes, Esq., M.W.S. Robert Patterson,
Esq. William Ick, Esq.

SECTION E. MEDICAL SCIENCE.

President.— John Yelloly, M.D., F.R.S.
Vice-Presidents. — Dr. Johnston. Dr. Roget, Sec. R.S. Dr.
Macartney, F.R.S.

Secretaries. — G. O. Rees, M.D. F. Ryland, Esq.

OFFICERS OF SECTIONAL COMMITTEES. Xlll

SECTION F. STATISTICS.

President. — Henry Hallam, Esq., F.R.S.

Vice-Presidents. — Sir Charles Lemon, Bart., F.R.S. G. R.
Porter, Esq., F.R.S.

Secretaries. — Francis Clarke, Esq. Rawson W. Rawson,
Esq. W. C. Tayler, Esq., D.C.L.

SECTION G. MECHANICAL SCIENCE.

Preside7it. — Professor Willis, F.R.S. Robert Stephenson,
Esq.

Fice- Presidents. — G. Rennie, Esq., F.R.S. Dr. Lardner,
F.R.S.

Secretaries. — T. Webster, Esq., Sec. Civ. Eng. W. Carp-
inael, Esq. Wm. Hawkes, Esq.

CORRESPONDING MEMBERS.

Professor Agassiz, Neufchatel. M. Arago, Secretary of the
Institute, Paris. A. Bache, Principal of Girard College, Phi-
ladelphia. Professor Berzelius, Stockholm. Professor De la
Rive, Geneva. Professor Dumas, Paris. Professor Ehrenberg,
Berlin. Baron Alexander von Humboldt, Berlin. Professor
Liebig, Giessen. Professor OErsted, Copenhagen. Jean Plana,
Astronomer Royal, Turin. M. Quetelet, Brussels. Professor
Schumacher, Altona.

BRITISH ASSOCIATION FOR THE

TREASURER'S ACCOUNT from

RECEIPTS.

£ s. d. £ s. d.

Balance in hand from last year's Account 670 7

Compositions from 132 Members, Newcastle and since « 641

Subscriptions, 1838, from 1944 Members, do 1944

Ditto 1839, from 37 do. do 37

Arrears 1837, from 37 do. do 37 1

' 2659 1

Dividend on ^£5500 in 3 per cent, consols, 12 months to"! icc n a

Julylast I ^^^ ^

Received on account of Sale of Reports, viz.

1st vol., 2nd Edition 27 7 2

2nd vol 28 10 4

3rd vol 37 13

4th vol 39 18 6

5th vol 44 4 4

ethvol 233 5 8

Lithographs sold 1 10 6

412 9 6

^3906 11 1

ADVANCEMENT OF SCIENCE.

1st August 1838 to 15th August 1839 inclusive.

PAYMENTS.

£ s. d.

Expenses of Meeting at Newcastle, allowed by Order of the Council 500

Disbursements by Local Treasurers 156 18 8

Salaries to Assistant Secretary and Accountant, 12 months to Mid-"1 „t„ ^ „

summer J

Grants to Committees for Scientific purposes, viz, for
Reduction of Stars in Histoire Ce- ri837 21 18 6") ,-, ,q ^

leste tl838 150 0/ ^'^ ^" "

Do. do. Lacaille 11

Catalogue of Stars, 1837 166 16 6

Land and Sea Level, 1838 52 1 4

Do. do. 1837 222

Tides' Discussions at Bristol 35 18 6

Mechanism of Waves, 1837 94 2

Do. do. 1838 50

Meteorological Observations, Plymouth 40 0\ tii^ n n

Do. do. hourly, Scotland 15 0/ ^^ " "

Completing Anemometer 8 10

Meteorology and Subterranean Temp. 1837, Thermometers 21 11
Atmospheric Air 16 1

Action of Sea Water on Iron { 1838 20 ol ^0

Action of Hot Water on Organic Bodies 3

British Fossa Ichthyology jjgg^ j^^ J o}^^'^ ^ ^

Fossil Reptiles 118 2 9

Mining Statistics 50

Duty of Cornish Steam Engines 50

Marine Steam Engines 100

Experiments on Vitrification (old grant) 9 4 7

Do. on Strength of Iron 100

Animal Secretions, 1837 10 10

Gases on Solar Spectrum, Action of 22

Railway Constants 1837 8 7 21 oa i o

Do. 1838 20 0/ ^^ ' ^

1595 11

Paid for Printing Reports, 6th vol 629 14 2

Do. for Engravings for do 171 19 10

801 14

Printing List of Members 77 12

Sundry Printing, Advertising, &c 38 14 6

Sundry Expenses on Publishing Reports 25 7 7

Balance in the hands of the Bankers 352 15

Do. Treasurer and Local Treasurers 107 18 4

460 13 4

Jt:3906 11

Xvi REPORT — 1839.

The following Reports on the Progress and Desiderata of dif-
ferent branches of Science have been drawn up at the request
of the Association, and printed in its Transactions.

1831-2.

On the progress of Astronomy during the present century,
by G. B. Ah-y, M.A., Astronomer Royal.

On the state of our knowledge respecting Tides, by J. W.
Lubbock, M.A., Vice-President of the Royal Society.

On the recent progress and present state of Meteorology,
by James D. Forbes, F.R.S., Professor of Natural Philosophy,
Edinburgh.

On the present state of our knowledge of the Science of Ra-
diant Heat, by the Rev. Baden Powell, M.A., F.R.S., Savilian
Professor of Geometry, Oxford.

On Thermo-electricity, by the Rev. James Gumming, M.A.,
F.R.S., Professor of Chemistry, Cambridge.

On the recent progress of Optics, by Sir David Brewster,
K.C.G., LL.D., F.R.S., &c.

On the recent progress and present state of Mineralogy, by
the Rev. WiUiam Whewell, M.A. F.R.S.

On the progress, actual state, and ulterior prospects of
Geology, by the Rev. William Conybeare, M.A., F.R.S.,
V.P.G.S., &c.

On the recent progress and present state of Chemical Science,
by J. F. W. Johnston, A.M., Professor of Chemistry, Durham.

On the application of Philological and Physical researches to
the History of the Human species, by J. C. Prichard, M.D.,
F.R.S., &c.

1833.

On the advances which have recently been made in certain
branches ofAnalysis,bytheRev.G. Peacock, M.A.,F.R.S.,&c.

On the present state of the Analytical Theory of Hydrostatics
and Hydrodynamics, by the Rev. John Challis, M.A. F.R.S., &c.

On the state of our knowledge of Hydraulics, considered as a
branch of Engineering, by George Rennie, F.R.S. , &c. (Parts
I. and n.)

On the state of our knowledge respecting the Magnetism of
the Earth, by S.H. Christie, M.A., F.R.S., Professor of Mathe-
matics, Woolwich.

On the state of our knowledge of the Strength of Materials,
by Peter Barlow, F.R.S.

On the state of our knowledge respecting Mineral Veins, by
John Taylor, F.R.S., Treasurer G.S., &c.

On the state of the Physiology of the Nervous System, by
WilHam Charles Henry, M.D.

DESIDERATA, ETC. XVU

On the recent progressof PhysiologicalBotany,byJohnLind-
ley, F.R.S., Professor of Botany in the University of London.

1834.

On the Geology of North America, by H. D. Rogers, F.G.S.

On the philosophy of Contagion, by W. Henry, M.D.,F.R.S.

On the state of Physiological Knowledge, by the Rev. Wm.
Clark, M.D., F.G.S., Professor of Anatomy, Cambridge.

On the state and progress of Zoology, by the Rev. Leonard
Jenyns, M.A., F.L.S., &c.

On the theories of Capillary Attraction, and of the Propaga-
tion of Sound as affected by the Development of Heat, by the
Rev. John Challis, M.A., F.R.S., &c.

On the state of the science of Physical Optics, by the Rev.
H. Lloyd, M.A., Professor of Natural Philosophy, Dublin.

1835.

On the state of our knowledge respecting the application of
Mathematical and Dynamical principles to Magnetism, Electri-
city, Heat, &c., by the Rev. Wm. Whewell, M.A., F.R.S.

On Hansteen's researches in Magnetism, by Captain Sabine,
F.R.S.

On the state of Mathematical and Physical Science in Bel-
gium, by M. Quetelet, Director of the Observatory, Brussels.

1836.

On the present state of our knowledge with respect to Mine-
ral and Thermal Waters, by Charles Daubeny, M.D., F.R.S.,
M.R.L A., &c.. Professor of Chemistry and of Botany, Oxford.

On North American Zoology, by John Richardson, M.D.,
F.R.S., &c.

Supplementary Report on the Mathematical Theory of Fluids,
by the Rev. J. Challis, Plumian Professor of Astronomy in the
University of Cambridge.

1837.
On the variations of the Magnetic Intensity observed at dif-
ferent points of the Earth's Surface, by Major Edward Sabine,
R. A., F.R.S.

On the various modes of Printing for the use of the Blind,
by the Rev. William Taylor, F.R.S.

On the present state of our knowledge in regard to Dimor-
phous Bodies, by Professor Johnston, F.R.S.

On the Statistics of the Four Collectorates of Dukhun, under
the British Government, by Col. Sykes, F.R.S.
1838.
Appendix to Report on the variations of Magnetic Intensity,
by Major Edward Sabine, R.A., F.R.S.

REPORT — 1839.

The following Reports of Researches undertaken at the request
of the Association have been published, viz.

1835.

On the comparative measurement of the Aberdeen Standard
Scale, by Francis Baily, Treasurer R.S., &c.

On Impact upon Beams, by Eaton Hodgkinson.

Observations on the Direction and Intensity of the Terrestrial
Magnetic Force in Ireland, by the Rev. H. Lloyd, Capt. Sabine,
and Capt. J. C. Ross.

On the Phaenomena usually referred to the Radiation of Heat,
by H. Hudson, M.D.

Experiments on Rain at different Elevations, by Wm. Gray,
jun., and Professor Phillips.

Hourly observations of the Thermometer at Plymouth, by
W. S. Harris.

On the Infra-orbital Cavities in Deers and Antelopes, by A.
Jacob, M.D.

On the Effects of Acrid Poisons, by T. Hodgkin, M.D.

On the Motions and Sounds of the Heart, by the Dublin
Sub-Committee.

On the Registration of Deaths, by the Edinburgh Sub-
Committee.

1836.

Observations on the Direction and Intensity of the Terres-
trial Magnetic Force in Scotland, by Major Edward Sabine,
R.A., F.R.S., &c.

Comparative view of the more remarkable Plants which cha-
racterize the Neighbourhood of Dublin, the Neighbourhood of
Edinburgh, and the South-west of Scotland, &c. ; drawn up for
the British Association, by J. T. Mackay, M.R.I.A., A.L.S.,
&c., assisted by Robert Graham, Esq., M.D., Professor of
Botany in the University of Edinburgh.

Report of the London Sub-Committee of the Medical Sectioh
of the British Association on the Motions and Sounds of the
Heart.

Second Report of the Dublin Sub-Committee on the Motions
and Sounds of the Heart. (See Vol. iv. p. 243.)

Report of the Dublin Committee on the Pathology of the
Brain and Nervous System.

Account of the Recent Discussions of Observations of the
Tides which have been obtained by means of the grant of money
which was placed at the disposal of the Author for that purpose
at the last Meeting of the Association, by J. W. Lubbock, Esq.

DESIDERATA, ETC. XIX

Observations for determining the Refractive Indices for the
Standard Rays of the Solar Spectrum in various media, by the
Rev. Baden Powell, M.A., F.R.S., Savilian Professor of Geome-
try in the University of Oxford.

Provisional Report on the Communication between the Arte-
ries and Absorbents on the part of the London Committee, by
Dr. Hodgkin.

Report of Experiments on Subterranean Temperature, under
the direction of a Committee, consisting of Professor Forbes,
Mr. W. S. Harris, Professor Powell, Lieut. -Colonel Sykes, and
Professor Phillips (Reporter).

Inquiry into the validity of a method recently proposed by
George B. Jerrard, Esq., for Transforming and Resolving
Equations of Elevated Degrees : undertaken at the request of
the Association by Professor Sir W. R. Hamilton.

1837.

Account of the Discussions of Observations of the Tides
which have been obtained by means of the grant of money which
was placed at the disposal of the Author for that purpose at the
last Meeting of the Association, by J. W. Lubbock, Esq.,
F.R.S.

On the difference between the Composition of Cast Iron
produced by the Cold and the Hot Blast, by Thomas
Thomson, M.D., F.R.SS. L. & E., &c., Professor of Chemistry,
Glasgow.

On the Determination of the Constant of Nutation by the
Greenwich Observations, made as commanded by the British
Association, by the Rev. T. R. Robinson, D.D.

On some Experiments on the Electricity of Metallic Veins,
and the Temperature of Mines, by Robert Were Fox.

Provisional Report of the Committee of the Medical Section
of the British Association, appointed to investigate the Com-
position of Secretions, and the Organs producing them.

Report from the Committee for inquiring into the Analysis of
the Glands, &c. of the Human Body, by G. O. Rees, M.D.,
F.G.S.

Second Report of the London Sub-Committee of the British
Association Medical Section, on the Motions and Sounds of
the Heart.

Report from the Committee for making experiments on the
Growth of Plants under Glass, and without any free communi-
cation with the outward air, on the plan of Mr. N. I. Ward,
of London.

Report of the Committee on Waves, appointed by the British
b2

XX REPORT— 1839.

Association at Bristol in 1836, and consisting of Sir John Robi-
son, K.H., Secretary of the Royal Society of Edinburgh, and
John Scott Russell, Esq., M.A., F.R.S. Edin. (Reporter).

On the relative Strength and other mechanical Properties of
Cast Iron obtained by Hot and Cold Blast, by Eaton Hodgkinson.

On the Strength and other Properties of Iron obtained from
the Hot and Cold Blast, by W. Fairbairn.

1838.

Account of a Level Line, measured from the Bristol Channel
to the English Channel, during the Year 1837-8, by Mr.
Bunt, under the Direction of a Committee of the British As-
sociation. Drawn up by the Rev. W. Whewell, F.R.S. , one
of the Committee.

A Memoir on the Magnetic Isoclinal and Isodynamic Lines
in the British Islands, from Observations by Professors Hum-
phrey Lloyd and John Philhps, Robert Were Fox, Esq., Cap-
tain James Clark Ross, R.N., and Major Edward Sabine,
R.A., by Major Edward Sabine, R.A., F.R.S.

First Report on the Determination of the Mean Numerical
Values of Railway Constants, by Dionysius Lardner, LL.D.,
F.R.S., &c.

First Report upon Experiments, instituted at the request of
the British Association, upon the Action of Sea and River
Water, whether clear or foul, and at various temperatures,
upon Cast and Wrought Iron, by Robert Mallet, M.R.I. A.,
Ass. Ins. C.E.

Notice of Experiments in progress, at the desire of the
British Association, on the Action of a Heat of 212° Fahr.,
when long continued, on Inorganic and Organic Substances,
by Robert Mallet, M.R.I.A.

Experiments on the ultimate Transverse Strength of Cast
Iron made at Arigna Works, Co. Leitrim, Ireland, at Messrs.
Bramah and Robinson's, 29th May, 1837.

Provisional Reports and Notices of Progress in Special Re-
searches entrusted to Committees and Individuals.

1839.

Report on the present state of our knowledge of Refractive
Indices for the Standard Rays of the Solar Spectrum in dif-
ferent media. By the Rev. Baden Powell, M.A.,fF.R.S., F.G.S.,
F.R.Ast.S., Savilian Professor of Geometry, Oxford.

Report on the application of the sum assigned for Tide Cal-
culations to Mr. Whewell, in a Letter from T. G. Bunt, Esq.,
Bristol.

DESIDERATA, ETC. XXI

Notice of Determination of the Arc of Longitude between
the Observatories of Armagh and Dublin. By the Rev. T. R.
Robinson, D.D., &c.

Report of some Galvanic Experiments to determine the
existence or non-existence of Electrical Currents among Stra-
tified Rocks, particularly those of the Mountain Limestone
formation, constituting the Lead Measures of Alston Moor.
By H. L. Pattinson, Esq.

Report respecting the two series of Hourly Meteorological
Observations kept in Scotland at the expense of the British
Association. By Sir David Brewster, K.H., LL.D., F.R.S.
L. and E.

Report on the subject of a series of Resolutions adopted
by the British Association at their Meeting in August, 1838,
at Newcastle.

Report on British Fossil Reptiles. By Richard Owen, Esq.,
F.R.S., F.G.S., &c.

Report on the distribution of Pulmoniferous Mollusca in the
British Isles. By Edward Forbes, M.W.S., For. Sec. B.S.

Third Report on the Progress of the Hourly Meteorological
Register at the Plymouth Dock-yard, Devonport. By W. Snow
Harris, Esq., F.R.S.

The following Reports and Continuations of Reports have been
undertaken to be drawn up at the request of the Association.

On the state of knowledge of the Phaenomena of Sound, by
Rev. Robert Willis, M.A., F.R.S., &c.

On the state of our knowledge respecting the relative level
of Land and Sea, and the waste and extension of the land on
the east coast of England, by R. Stevenson, Engineer to the
Northern Lighthouses, Edinburgh.

On Salts, by Professor Graham, F.R.S.

On the Differential and Integral Calculus, by Rev. Professor
Peacock, M.A., F.R.S., &c.

On the Geology of North America, by H. D. Rogers, F.G.S..,
Professor of Geology, Philadelphia.

On Vision, by Professor C. Wheatstone, F.R.S.

On the application of a General Principle in Dynamics to
the Theory of the Moon, by Professor Sir W. Hamilton.

On Isomeric Bodies, by Professor Liebig.

On Organic Chemistry, by Professor Liebig.

On Inorganic Chemistry, by Professor Johnston, F.R.S.

On Fossil Reptiles (continuatio)i), by Professor Owen, F.R.S.

xxii REPORT — 1839.

On the Salmonidae of Scotland, by Sir J. W. Jardine.

On the Caprimulgidse, by N. Gould, F.L.S.

On the state of Meteorology in the United States of North
America, by A. Bache.

On the state of Chemistry as bearing on Geology, by Pro-
fessor Johnston.

On Molluscous Animals and their Shells, by J. E. Gray,
F R S

On Ornithology, by P. J. Selby, F.R.S.E.

On the Specific Gravity of Steam, by a Committee, of which
Mr. B. Donkin is Secretary.

Recommendations for Additional Reports, Researches, and
Grants of Money sanctioned by the General Committee at
the Birmingham Meeting,

ADDITIONAL REPORTS ON THE STATE OF SCIENCE REQUESTED.

That Mr. W. J. Henwood be requested to furnish a Report
of his own observations on the Temperature of the deep Mines
of Cornwall.

That Mr. R. W. Fox be requested to furnish a Report of his
own observations on Subterranean Temperature.

That Professor Miller be requested to furnish a Report on
the recent progress and present state of the Science of Crystal-
lography.

That Professor Forbes be requested to furnish a supple-
mentary Report on Meteorology.

That Professor Powell be requested to furnish a supple-
mentary Report on Radiant Heat.

That Professor de la Rive, of Geneva, be requested to fur-
nish a Report on the recent progress and present condition of
Electro-Chemistry and Electro-Magnetism.

Additional Recommendations involving applications to Go-
vernment or Public Bodies sanctioned by the General Com-
mittee at the Birmingham Meeting.

GEOLOGY.

That with a view to supply one of the greatest desiderata at
present felt by geologists hi investigating the structure and
history of the earth, as well as to advance a branch of geology.

DESIDERATA, ETC. XXIU

for the study of which no adequate provision has hitherto been
made in any of the public institutions of this country, applica-
tion be made to the trustees of the British Museum to form a
conchological collection, if possible, under the same roof, and
which may include not only all known species of shells, whe-
ther recent or fossil, but likewise the varieties of form and
size which such species assume at different periods of their
growth, or from other causes, together with a series of the im-
pressions of shells which are found upon different rocks and
plaster casts from their impressions ; and that the Marquis of
Northampton be requested to bring this recommendation before
the Board of Trustees.

MINING RECORDS.

The Committee appointed at Newcastle, for the purpose of
applying to Government for a proper place for the deposit of
records connected with the mining transactions of Great Bri-
tain, having reported that a room adjoining the Museum of
Economic Geology had been appointed for their reception,
which would also be placed under the custody of a proper
person, it was resolved, — That the following gentlemen should
be appointed a Committee for the purpose of superintending
and making the necessary arrangements, and for assisting in
the collection and transmission of Mining Records : — Marquis
of Northampton, Sir Charles Lemon, Sir Philip G. Egerton,
John Henry Vivian, Esq., Davies Gilbert, Esq., J. S. Enys,
Esq., W. L. Dillwyn, Esq., Charles Lyell, Esq., the President
of the Geological Society, the Professors of Geology at the
Universities of Oxford, Cambridge, London, and Durham,
H. T. De la Beche, Esq., John Buddie, Esq., Thos. Sopwith,
Esq., Richard Griffith, Esq., James Barker, Esq., the Presi-
dent of the British Association, G. R. Porter, Esq., John
Taylor, Esq.

RBPORT 1839.

Synopsis of Sums appropriated to Scientific Objects by the
General Committee at the Birmingham Meeting.

Section A.

1. For the Reduction of Meteorological Obser-

vations, under the superintendence of Sir J.

Herschel £100

2. For the Reduction of Lacaille's Stars, under

the superintendence of Sir J. Herschel, the
Astronomer Royal, and Mr. Henderson . 189

3. For the Revision of the Nomenclature of the

Stars : Sir John Herschel, Mr. Whewell,

and Mr. Baily 50

4. For the Reduction of Stars in the Histoire

Celeste : Mr. Baily, the Astronomer Royal,

and Dr. Robinson 328 1 6

5. To extend the Royal Astronomical Society's

Catalogue : Mr. Baily, the Astronomer

Royal, and Dr. Robinson . c . . . . 343 3 6

6. For Magnetical Observations (Instruments,

&c.) : Sir J. Herschel, Mr. Whewell, Dr.

Peacock, Mr. Lloyd, and Major Sabine . 400

7. Hourly Meteorological Observations in Scot-

land : Sir D. Brewster and Mr. Forbes . 50 12 4

8. To the Committee on Waves : Sir J. Robi-

son and Mr. J. S. Russell 30

*9. For the Reduction and Tabulation of Obser-
vations on Subterranean Temperature : un-
der the superintendence of Prof. Forbes . 20
10. For Tide Discussions : Mr. Whewell ... 50
*11. For procuring an Engraved Plate for tabu-
lating observations : under the direction of

Prof. Forbes 10

12. For the Translation of Foreign Scientific
Memoirs : Major Sabine, Dr. R. Brown,
Dr. Robinson, Sir J. Herschel, and Prof.
Wheatstone. (In the application for this
grant the Committee of Section D. also

joined.) 100

*13 For Observations with Prof. Whewell's Ane-
mometer at Plymouth : under the superin-
tendence of Mr. Snow Harris 10

Carried forward £1680 17 4

SYNOPSIS. :

Brought forward £1680 17
*14 For Alterations and Observations with Mr.
Osier's Anemometer at Plymouth : under
the superintendence of Mr. Snow Harris . 30
15. For the Expenses of Meteorological Obser-
vations at Plymouth (additional grant) : Mr.

W. S. Harris 40

*16. For procuring and fixing an Anemometer on
Mr. Osier's construction, to be placed at
some station in Scotland : under the super-
intendence of Prof. Forbes 60

£1810 17
Section B.

17. For Researches on Atmospheric Air : Mr.

W. West 24

18. For Experiments on the Action of Sea Water

on Cast and Wrought Iron : Mr. Mallet and

Prof. Davy 30

19. For Experiments on the Action of Water of

212° on Organic Matter: Mr. Mallet . . 7

20. For Experiments on the Specific Gravity of

the Gases : Dr. Prout, and Prof. Clark of

Aberdeen 40

*21. For defraying the expenses of certain Expe-
riments by Prof. Schonbein, of Basle, on
the connexion between Chemical and Elec-
trical Phsenomena : the result to be reported
to the Association at their next Meeting . 40

£141

Section C.

22. For the Promotion of our Knowledge of Bri-
tish Fossil Reptiles, by a Report on that
subject : Mr. Greenough, Mr. Lyell, and
Mr. Clift 81 17

£81 17
Section D.

23. For Experiments on the Preservation of
Animal and Vegetable Substances : Prof.

XXvi REPORT — 1839.

Henslow, Mr. Jenyns, Dr. Clark, and

Prof. Gumming • . . . £6

*24. For Procuring Drawings, illustrative of the
Species and their Details, of the Radiate
Animals of the British Islands, to accom-
pany a Report of the State of our Know-
ledge of such Animals : under the superin-
tendence of Mr. Gray, Mr. Forbes, Mr.
Goodsir, Mr. Patterson, Mr. Thompson of
Belfast, and Dr. George Johnston ... 50

*25. For Researches with the Dredge, with a view
to the investigation of the Marine Zoology
of Great Britain, the Illustration of the
Geographical Distribution of Marine Ani-
mals, and the more accurate determination
of the Fossils of the Pleiocene Period : un-
der the superintendence of Mr. Gray, Mr.
Forbes, Mr. Goodsir, Mr. Patterson, Mr.
Thompson of Belfast, Mr. Ball of Dublin,
Dr. George Johnston, Mr. Smith of Jordan
Hill, and Mr. A. Strickland 60

*26. For the Engraving of Skeleton Maps for re-
cording the Distribution of Plants and
Animals : under the superintendence of
Prof. R. Graham, Dr. Greville, Mr. Brand,
Mr. H. Watson, Mr. J. E. Gray, and Mr.
E. Forbes 20

*27. For Printing and Circulating a Series of
Questions and Suggestions for the use of
travellers and others, with a view to procure
Information respecting the different races
of Men, and more especially of those which
are in an uncivilized state : the Questions
to be drawn up by Dr. Prichard, Dr. Hodg-
kin, Mr. J. Yates, Mr. Gray, Mr. Darwin,
Mr. R. Taylor, Dr. Wiseman, and Mr.
Yarrell 5

£141

Section E.

28. For Experiments on the Sounds of the Heart :

Dr. Clendinning 25

Carried forward £25

SYNOPSIS. xxvii

Brought forward £25

29. For Experiments on the Lungs and Bronchi :

Dr. C. Williams 25

30. For Experiments on Medico-Acoustic In-

struments : Dr. Yelloly 25

31. For Investigations on the Veins and Absorb-

ents : Dr. Roget 25

32. For Experiments on Acrid Poisons : Dr.

Roupell 25

£125
Section F.

33. For Statistical Inquiries in Schools for the

Working Classes : under the superintend-
ence of Sir Charles Lemon, Mr. Hallam,
and Mr. G. R. Porter 100

£100

Section G.

*34. For Inquiries respecting the Duty of Ame-
rican Steam Boats : under the direction of
Mr. W. Fairbairn, Dr. Lardner, Mr. I. S.
Russell, Mr. John Taylor, and Mr. Allen
of New York 50

35. For Inquiries respecting the Duty of En-

gines not in Cornwall : Mr. W. Bryan
Donkin, Mr. James Simpson, Mr. G. H.
Palmer, and Mr. T. Webster, Sec. ... 20

36. For Experiments on the Hot-blast Iron as

compared with Cold- blast Iron : Mr. Hodg-
kinson, Mr. W. Fairbairn, and Mr. P. Clare 100
*37 For Experiments on the Increase, after long
periods, in the Deflexion of Beams and
other Structures, variously loaded : under
the superintendence of Mr. George Cottam,
Mr. J. Glynn, and Mr. T. Edginton . . 20
38. For Experiments on the Forms of Vessels :
Sir J. Robison, Mr. I. S. Russell, and Mr.
James Smith 200

390

REPORT 1839.

Section A £1810 17 4

— B 141

— C 81 17 3

— D 141

— E 125

— F 100

— G 390

2789 14 7

The above grants expire at the Meeting in 1840, unless the
Recommendations shall have been acted on, or a continuance of
the grant applied for by the Sectional Committees, and ordered
by the General Committee. Those marked thus *, relating to
subjects on which no previous resolution has been adopted, are
generally explained at greater length than the others, which are
renewals or continuations of former grants for objects which
have been detailed in previous volumes.

In grants of money to Committees for purposes of Science,
the member first named is empowered to draw on the Treasurer
for such sums as may from time to time be required. The
General Committee does not contemplate, in the grants, the
payment of personal expenses to the members.

On Monday evening, August 29th, the President, the Rev.
W. V. Harcourt, took the Cliair in the Town Hall, and de-
livered an Address to the Meeting (see next page).

On Saturday evening, the Concluding General Meeting
of the Association took place in the Town Hall, when an ac-
count of the Proceedings op the General Committee was
read by the Rev. Professor Peacock.

ADDRESS

THE REV. W. VERNON HARCOURT.

A FEW weeks since I bade farewell to one whose friendship I owe to
this Association, setting forth on an enterprize full of labour and
hazard, but full also of such visions of glory, and so brilliant a pro-
spect of scientific conquests, that for a mind combining the high aims
of the philosopher with the intrepidity of the sailor, no danger, no
difficulty, no inconvenience seemed to exist, even in those regions where
Stern famine guards the solitary coast.
And winter barricades the realms of frost.

We sat down. Gentlemen, before his chart of the Southern Seas, and
the unapproached pole of the earth : he showed me his intended track ;
he pointed out the happy coincidence of the recent discovery (one
of the debts which science owes to commerce) of two small islands in
those seas ; he put his finger upon the spot which theory assigns for
the magnetic pole of verticity, corresponding to that which he had
himself discovered in the opposite hemisphere, and so situated, inter-
mediately between the two newly-discovered insular stations, that
should he not reach the pole itself, they would enable him to verify or
correct the theory ; and again, on the spot where his course would cross
the point of maximum intensity which the same theory involves. We
next reviewed the places at which he is commissioned to plant, on his
way, three magnetical and meteorological observatories, — St. Helena,
the Cape, and Van Diemen's Land, and those at which he himself
especially wished to observe, — at Kerguelen's Land, New Zealand, and
other stations on the land and ice ; and we talked of all these as part
only of a system of observations simultaneous or combined, stretching
from one side of the earth to the other, undertaken or promised, through
the whole extent of the British empire, from Montreal to Madras, and
blending in co-operation with chains of observatories established, or on
the point of being established, by other nations in the four quarters of
the world.

I confess, Gentlemen, I felt, as one of the white and bright moments

of life, such a conversation, at such a moment, with a man, of whom,
as he is no longer with us, I may venture to say, that he is worthy of
being employed on so glorious a service.

When I had bidden him adieu, I had leisure to reflect on the possible
consequences of his expedition, and the plan of which it forms a part, —
The problem of terrestrial magnetism solved — first, the laws of the
changes of its elements detected, their constant parts determined, and
the whole proved to coincide with a theory based on a legitimate re-
presentation of known facts — then, the lines of its force and direction
truly drawn, the deviations predicted, and the corrections supplied —
in the immediate view of practical consequences, our ships finding in
their compass-needles a more unfailing guide than in the fragile time-
piece or the cloudy sky — in the distant horizon of higher and yet more
fruitful speculation, the true cause of the phsenomena — and therein per-
haps a completion of what Newton began — a revelation of new cosmical
laws — a discovery of the nature and connexion of imponderable forces
■ — all these the possible results of approaching the heights of theory on
what may prove to be their most accessible and measurable side.

Afterwards I thovight of the causes which had conduced to this
grand undertaking, which had prompted the British Government to
seek these laurels, and cull these fruits of jjeace, by the outfit of the most
important and the best-appointed scientific expedition which ever
sailed from the ports of England. Well were the government both
prompted and seconded by the science of the country. I saw the
apartments of the Royal Society moved by a fresh spirit of energy and
zeal ; its most distinguished members sacrificing personal considera-
tions, and postponing individual to public objects — Committees meet-
ing and corresponding, to perfect the instruments of observation, and
prepare the plans for observing — distant members, at Dublin and
Woolwich, deputed to instruct the observers. It seemed as if the days
of Wallis, and Wilkins, and Wren, and Boyle, and Evelyn were revived ;
and whom did I recognise, Gentlemen, among those who were thus
zealously and effectively employed ? Their faces were familiar to me ;
they were the same men who first proposed the subject, and discussed it
together at the meetings of this Association, the same who went from
you to call the national attention to it, and had since added to that call
all the influence and all the efficacy of the Royal Society. The indi-
vidual, again, appointed to command the expedition, and conduct the
observations, and those also who were selected to instruct the other
observers, who were they ? They were not only taken from the ranks of
the Association, but they had perfected the instruments of observation,

and gained additional experience in observing, during their co-operative
labours in its service. When Captain James Ross and Major Sabine,
and Profs. Lloyd and Phillips, and Mr. Fox, were engaged in ascer-
taining the curves of the magnetic elements across the British islands,
vv^ith unexampled completeness, they performed a national vi^ork import-
ant in itself, but still more important as leading on to greater under
takings. But lastly, Gentlemen, whence proceeded that theory which
it is the highest object of all this philosophical energy, and all this na-
tional liberality to put to the test — the first profound attempt to bring
the magnetism of the earth under the dominion of Calculation ? Let
the illustrious author of it speak for himself: " Several years ago,"
says Gauss, " I repeatedly began attempts of this kind, from all of
which the great inadequacy of the data at my command forced me to
desist." " The appearance of Sabine's map of the total intensity, in the
7th Report of the British Association for the Advancement of Science,
has stimulated me to undertake and complete a new attempt," — an at-
tempt, Gentlemen, which, whether we consider the importance of its
results, or the labour and the strength expended upon it by this great
mathematician, reflects high credit on the author of the map, which
provided for such a theory numerical expressions, and does honour to
the Institution which was in any the least degree instrumental to its
production.

In what I have been saying. Gentlemen, I have been desirous of
pointing to that spirit of co-operation which our meetings have called
forth in this country. We see among us at length the novelty of many
fraternities of fellow-labourers working for a common cause, on a com-
mon plan, with a perfect mutual understanding. This is the only means
of advancing the great branches of knowledge in which space is a
necessary element, and it is the best security for a constant progress in
all. Science, in a country where every man labours alone, has periods
of darkness as well as light, and resembles those stars which are seen
from time to time to " pale their ineffectual fires "; but there need be
no fear of its decline, there can be no check in its advance, when it de-
pends not on the prowess of any single arm, but on the force of its
numbers and the order of its array.

The system of your meetings. Gentlemen, has brought together
things which ought never to be disjoined — the principles of science,
with their application to human use. After gathering your first mem-
bers from our ancient schools of learning, you passed to the marts of
commerce, and are now come to the heart of the manufactures of Eng-
land, and look round on all the resources and creations of mechanical

A 2

art. The theorist and mechanician here meet together to the mutual
advantage of both ; witness on the one part the instrument now work-
ing in the Philosophical Institution of this town*, and almost supplying
the place of a constant observer, which is about to measure the force
of the wind at every instant of time, at St. Helena, the Cape of Good
Hope, Van Diemen's Land, and near the southern Pole. On the other
hand, I may mention an anecdote which shows by how circuitous a
route art has sometimes been driven to seek the aid of science. Du-
ring the war between France and England, a Frenchman brought with
him the discovery of a great chemical philosopher in Paris, to barter
for a secret of the English manufactures ; not finding in Lancashire
the person he sought, he left a message, returned to London, and was
imprisoned under the Alien Act; to prison, however, the English
manufacturer followed him, obtained his secret and his liberation,
made his own fortune, and enriched his country f.

But need I go further than the immediate vicinity of this town for
an instance, the most striking on record, of the mighty influence which
the introduction of a new principle in science can exercise on all the
arts of life ? The history of the improvement of the steam-engine by
Watt finely illustrates this truth. In the eulogium of that great man
lately published, the Secretary of the French Academy has justly and
eloquently displayed, by this memorable example, the power which
resides in the unaided genius, industry, and patience, of a single indi-
vidual, applying his mind to the fruitful ap^Dlication of a scientific truth,
and the incalculable extent to which he may promote the welfare of
his country, and benefit the whole family of mankind. He has taught
us also to reflect " in what an humble condition of life those projects
were elaborated which were destined to carry the British nation to a
degree of power hitherto unheard of J."

But whilst I refer you to this volume. Gentlemen, for an admirable
exposition of important truths, I feel myself called upon to state, that
the zeal of M. Arago has carried him too far, when it has tempted him
to transfer to Watt those laurels which both time and truth have fixed
upon the brow of Cavendish.

It is far from my views, to draw any comparison between two
illustrious names, of which one stands as high in the discovery of
natural facts, as the other does in their useful application ; but let

* Mr. Osier's self-registering Anemometer.

t This anecdote, with the names of the individuals, was related to me by
the late Dr. Henry.

I Annuaire, pour Van 1839. p. 236.

us hold a just and even balance between genius that rises superior
to the pressure of circumstances, and that which reaches to at least
equal intellectual heights, unseduced by rank and riches. The Se-
cretary of the Academy has not confined himself to taking from Caven-
dish the honour of his discoveries, but has cast a cloud of suspicion
on his veracity and good faith : he has, in fact, imputed to him, the
claiming discoveries and conclusions which he borrowed from others,
of inducing the Secretary of the Royal Society to aid in the fraud, and
even causing the very printers of the Transactions to antedate the pre-
sentation-copies of his paper.

Yet this. Gentlemen, is the man to whom, at his death in 1810, one
who knew and was competent to speak of him bore the following tes-
timony : — " Of all the philosophers of the present age," said Davy,
" Mr. Cavendish combined the greatest depth of mathematical know-
ledge with delicacy and precision in the methods of experimental re-
search. It might be said of him, what, perhaps, can hardly be said of
any other, that whatever he has done has been perfect at the moment
of its production : his processes were all of a finished nature ; executed
by the hand of a master, they required no correction; and, though many
of them were performed in the very infancy of chemical knowledge, yet
their accuracy and their beauty have remained unimpaired, amidst the
progress of discovery, and their merits have been illustrated by discus-
sion, and exalted by time. In general, the most common motives which
induce men to study, is the love of distinction and glory, or the desire
of power ; and we have no right to object to these motives ; but it
ought to be mentioned, in estimating the character of Mr. Cavendish,
that his grand stimulus to exertion was evidently the love of truth
and knowledge : unambitious, unassuming, it was often with difficulty
that he was persuaded to bring forward his important discoveries. Pie
disliked notoriety ; he was, as it were, fearful of the voice of Fame ; his
labours are recorded with the greatest simplicity, and in the fewest
possible words, without parade or apology ; and it seemed as if, in pub-
lication, he was performing, not what was a duty to himself, but a duty
to the public." — " Since the death of Newton," he concludes, " En-
gland has sustained no scientific loss so great as that of Cavendish : his
name will be an object of more veneration in future ages, than at the
present moment ; though it was unknown in the busy scenes of life, or
in the popular discussions of the day, it will remain illustrious in the
annals of science, which are as unperishablc as that nature to which
they belong ; it will be an immortal honour to his house, to his age,
and to his country."

Alas, Gentlemen, for human predictions and posthumous fame I
Who could have foreseen that, ere thirty years had elapsed, so opposite
a view of the labours and character of this philosopher would pro-
ceed from one of the most enlightened of his successors ? But for the
sake of justice, and because there is no page in the histoiy of expe-
rimental philosophy more instructive than that to which this question
carries us back, I now ask permission to give equal publicity to a
different view, and to offer such a sketch of the great chemical dis-
covery of the composition of water, as may perhaps help to eluci-
date the truth.

According to the statements of this publication, the person who
brought the first evidence of the composition of water, by proving that
the water produced is equal in weight to the gases consumed in its pro-
duction, was Dr. Priestley ; the person who first drew the conclusion
that water is composed of oxygen and hydrogen, was Watt. Now, the
former of these statements has not only no real foundation, but is con-
tradicted by the repeated assertions of Priestley himself, who constantly
maintained, that in no experiment made with care had he ever found
the weight of the fluid produced, equal to the sum of gases, or the fluid
itself pure water. The latter. Gentlemen, has no foundation, except in
the licence which M. Arago has used, of quoting the words of Watt
otherwise than they really stand. Nor can there be a stronger instance
of the inconvenience of such translations, than the difference of mean-
ing and value in the words thus substituted for each other— hydrogen^
for example, put iov phlogiston.

What is it, Gentlemen, that gives importance to this discovei'y in the
history of science ? Not merely, as has been too popularly stated, that
it banished water from among the elements, but that whilst it accounted
for an infinite number of phaenomena, it introduced into chemistry
distinctness of thought and accuracy of reasoning, and led to the gene-
ral prevalence of a sounder logic. The prejudice of that epoch was,
not to regard compound substances as simple, but to consider un-
decompounded substances as compound. The hypothesis, that a prin-
ciple called Phlogiston entered into the composition of a great variety
of bodies which we now consider simple, had infected the whole of che-
mistry. This hypothesis, at first but a conjectural attempt to generalise
the phsenomena of combustion, gradually made itself a coat of patch-
work out of the successive discoveries of half a century, and arrived
at playing as many feats in philosophy, as the harlequin in a pantomime.
In the very paper of Watt on which this claim is founded, we find,
first, inflammable gas, then charcoal, then sulphur, then nitrogen, to be

all different forms of the same phlogiston, united with a minute portion
of different bases; we find it combining with oxygen, in one propor-
tion, to form carbonic acid, in another, nitrogen, in another, water.
Its affinities with these bases, and with all the metals, had been deter-
mined by Bergman, as well as the relative weights in which it entered
into composition : and to complete all, the year before the publication
of Cavendish's experiments, Kirwan had proceeded to give a table of
the absolute weights — had computed for instance that fourteen cubic
inches of nitrous air contain 0*938 of a grain of phlogiston, and had
actually deduced a law for these weights, corresponding with the spe-
cific gravities of the metals.

You will easily conceive. Gentlemen, the effect on a purely experi-
mental science of such a hypothesis as this, and you must add the effect
of other hypotheses, equally prevalent, which bestowed similar che-
mical affinities on the principles of light and heat. Bergman calcu-
lated the weight of phlogiston " in pollice cuhico decimali " of hydrogen
to be y§YT of ^ pound, and the weight of specific heat in the same to
be yf Q of a pound. His method of arriving at results which have such
a face of precision furnishes a very curious specimen of analytical rea-
soning. He assumes — 1st, That charcoal consists of fixed air, alkaline
earth, and phlogiston : he ascertains as well as he can the weight of
the two former constituents, and calculates that of the latter from the
loss in his analysis. 2nd, He assumes that phlogiston exists in iron in
the ratio to that in charcoal of their respective effects in phlogisticaiing,
or alkalizing, an equal quantity of nitre ; he determines this proportion,
and from the 1st experiment deduces the absolute weight of phlogiston
in a given weight of iron. 3rd, He assumes hydrogen to consist of
phlogiston, and matter of heat ; he assumes further that the phlogiston
in a given volume of hydrogen is proportionate to the phlogiston in
the iron from which it is evolved by the action of acids ; he deter-
mines by experiment what the weight of iron is which produces a
given volume of hydrogen, and he concludes from the two data before
obtained the absolute weight of the phlogiston ; this he subtracts from
the total weight of the hydrogen, and thus determines the absolute
weight of the matter of heat*. In like manner you find the ideas of
Watt respecting the composition of water connected with, and spring-
ing out of the idea, that it was reconvertible, not simply into phlogiston
and dephlogisticated air, but, by an intimate union of the latter with the
principle of heat, into phlogiston and atmospheric air. By such loose

* See Bergman ' de Attract, electivis', pp. 413, 440, ' de Analysi Ferri,' p.
24, Opuscula Phys. et C/tem. vol. iii. Upsal. 1783.

reasoning as this, some of the best chemists of the day were misled, not
only as to the direction of their labours, but even the results of their ex-
periments. But in Cavendish's celebrated inquiry into the causes where-
by air suffers diminution in a variety of processes then termed phlogistic,
it is well worthy of remark how steadily he moves on from truth to truth,
on every point on which experiments afforded ground for reasoning, un-
fettered by the complexity of the phlogistic theory ; and it is equally
remarkable, how loose he sits to the favourite hypothesis to which the
rest of his countrymen clung with such persevering tenacity. He,
first of all his contemporaries, did justice to the rival theory recently
proposed by Lavoisier, and weighed it in equal scales before the pub-
lic eye. He alone seemed to understand, as it became a disciple of
the school of Newton, the true use of a hypothesis : he valued neither
system otherwise than as an expression of facts, or as a guide to future
inquiry. He took these opposite hypotheses, and retrenched their su-
perfluities ; he pared off from both, their theories of combustion, and
their affinities of imponderable for ponderable matter, as complicating
chemical with physical considerations ; and he then corrected and ad-
j usted them with admirable skill to the actual phaenomena, not bending
the facts to the theory, but adapting the theory to the facts.

Allow me to give you an instance of this adaptation. Priestley had
stated, that he had converted charcoal into inflammable gas by the sim-
ple action of the burning lens, and obtained it from pure iron, by the
same means, and had drawn the consequence, that iron was composed
of phlogiston united to the basis, or calx, of iron, and that charcoal and
inflammable gas were pure phlogiston. " I had no suspicion," he says*,
" that water was any part of inflammable air ;" " yet that water in great
quantities is sometimes produced from burning inflammable and de-
phlogisticated air, seemed to be evident from the experiments of Mr.
Cavendish and M. Lavoisiei'. I have also frequently collected consi-
derable quantities of water in this way, though never quite so much as
the two kinds of air decomposed." " Afterwards, seeing much water
produced in some experiments in which inflammable air was decom-
posed, I was particularly led to reflect on the relation which they bore
to each other, and especially Mr. Cavendish's ideas on the subject. He
had told me, notwithstanding my former experiments, from which I had
concluded that inflammable air was pure phlogiston, he was persuaded
that water was essential to the production of it, and even entered into
it as a constituent principle. At that time I did not perceive the force

* Priestley on Air, ed. 1790, part 3. sect. 4.

of the arguments which he stated to me, especially as, in the experi-
ments with charcoal, I totally dispersed any quantity of it with a burn-
ing lens, ill vacuo, and thereby filled my receiver with nothing but in-
flammable air. I had no suspicion that the wet leather on which my
receiver stood could have influence in the case, while the piece of char-
coal was subject to the intense heat of the lens, and placed several
inches above the leather. I had also procured inflammable air from
charcoal in a glazed earthen retort two whole days successively, in
which it had given inflammable air without intermission : also iron
filings in a gun-barrel, and a gun-barrel itself had always given in-
flammable air whenever I tried the experiment." " But, my attention
being now fully awake to the subject, I found that the circumstances
above mentioned had actually misled me." " Being thus apprised of the
influence of unperceived moisture in the production of inflammable
air, and willing to ascertain it to my perfect satisfaction, I began with
filling a gun-barrel with iron filings in their common state, without
taking any precaution to dry them, and found that they gave air as
they had been used to do ;" " at length however, the production of in-
flammable air from the gun-barrel ceased, but on putting water into it,
the air was produced again ; and a few repetitions of the experiment
fully satisfied me that I had been too precipitate in concluding
that inflammable air is pure phlogiston." Dr. Priestley afterwards
gives an account (Phil. Trans. 1785) of his repeating Lavoisier's
celebrated experiment, in which the decomposition of water was
proved by passing steam through an iron tube. " I was determined,"
he says, " to repeat the process with all the attention I could give
to it ; but I should not have done this with so much advantage if
I had not had the assistance of Mr. Watt, who always thought
that M. Lavoisier's experiments by no means favoured the conclu-
sion that he drew from them. As to myself, I was for a long time
of opinion that his (Lavoisier's) conclusion was just, and that the in-
flammable air was really furnished by the water being decomposed
in the process ; but though I continued to be of this opinion for some
time, the frequent repetition of the experiments, with the light which
Mr. Watt's observations threw upon them, satisfied me at length, that
the inflammable air came from the charcoal or the iron."

It appears from these statements, and may be still more clearly ga-
thered from Cavendish's own remarks * in his " Experiments on Aii-," that
he not only set Priestley right as to his supposed fact of the production

* Phil. Trans, vol. Ixxiv. p. 137.

of hydrogen from dry iron, but furnished a theory by which the disci-
ples of phlogiston* might nevertheless maintain their ground both in
this and other cases. The explanation which his theory afforded in
this instance was, that the inflammable air, due to the unperceived moist-
ure in the iron filings, or in the air of the vessels, is evolved by the force
of double affinities in the following manner — the water, decomposing
the iron, combines in part with its basis, and in part with the phlogiston
(or dry hydrogen) which it was supposed by hypothesis to contain ; form-
ing by the one combination the calx, or oxide, of iron, and by the other,
inflammable gas f. Such a representation was not incompatible with
any known facts, and Cavendish had his own reasons for giving it on
the whole a preference over that which seems to us so much more plain
and reasonable : its fault as a theory was, that it was needlessly hypo-
thetical, and that it was part of a system overloaded with a multitude
of hypotheses.

Lavoisier was the first to introduce into chemistry a juster language
and a safer manner of stating facts ; he caught sight of a principle
which has been since laid down by Davy as a genei'al proposition, and
has contributed much to the distinctness of chemical science, — the prin-
ciple that every body is to be reasoned about as simple till it has been
proved by direct evidence to be compound. To Cavendish, trained in
the rules of demonstration, and gifted with a sagacity and clearness of
conception beyond his fellows, hypothetical thoughts and expressions
were no stumbling-block ; and he seems therefore not to have felt how
great an obstacle they present to the general movement of science as it
floats upon the tide of a thousand understandings.

If the question then be, who reformed the expressions and logic of
chemistry, or who furnished the simple terms in which we now state the
elements of water ? the answer is, Lavoisier ; but if it be, who dis-
covered and unfolded the most important facts on which that reforma-

* That Watt derived from Cavendish his views on this subject, is evident
from the parenthetical introduction of his altered opinion that inflammable
gas was not pure phlogiston, but a combination of phlogiston and water, in
the middle of experiments and arguments to prove the contrary, without assign-
ing any reason, and after the publication of Cavendish's theory. See Mr.
Watt's Thoughts. Phil. Trans, vol. Ixxiv. p. 330.

t Cavendish assigns as his principal reason for believing inflammable gas
to be a compound of this description, that it does not unite with oxygen at
common temperatures ; but it is likely that he was influenced also by the re-
sult of his experiments on "a diiferent kind of inflammable air, namely, that
from charcoal," for which, see Postscript, p. 38.

tion relied ? who detected and proved the composition of water, and
deduced the train of corollaries which flowed from it ? the answer is,
Cavendish. The discovery was not one of those which was within every
man's reach, especially in an age of loose experiment and inconclusive
reasoning : it was one which could never have been made, but by a strict
appreciation of quantities, and a careful elimination of the sources of
error : it formed part of the solution of the difficult problem, which at
that time occupied the attention of all the chemists in Europe — the
cause of the diminution of atmospheric air, in six several cases — in the
passage through it of the electric spark, in its burning with hydrogen, in
its contact with nitrous gas, in respiration, in the inflammation of phos-
phorus and sulphur, and in the calcination of metals. These phasno-
mena had been accounted for by a supposed phlogistication of the air,
and a consequent formation and absorption of carbonic acid ; Lavoisier
stood alone in attributing the phsenomena of the four last classes to
their true cause. When Cavendish took up the problem, he began by
proving that no carbonic acid was necessarily produced in any of these
processes : and then. Gentlemen, he turned to use a well-timed but in-
correct experiment of an inhabitant of this town, (Mr. Warltire,) and
he made it the basis of a series of analytic and synthetic researches,
unequalled then, and never since surpassed, by which he demonstrated,
as a means of arriving at the solution of his problem, — 1st, The quan-
titive composition of the atmosphere ; 2nd, The combination of hy-
drogen with oxygen and the quantitive composition of water; 3rd,
The chemical union of nitrogen with oxygen and the constitution of
nitric acid. From these experimental data he deduced the true causes
of the diminution of the air in the burning of hydrogen, and in the
passage of the electric spark ; he adopted Lavoisier's conclusion re-
specting the burning of metals and other inflammable matters, gave
the true account of the composition of the nitrates of potash and
mercury, explained the constitution of vegetable substances, and the
origin of the oxygen which they exhale, and finally corrected the pre-
mature generalization which had led the French philosopher to con-
sider that gas as the principle of acidity.

Such, Gentlemen, were the splendid results of this investigation, such
the reinforcement which Cavendish brought to the nascent reformation
of chemistry. Equally worthy of observation were the means employ-
ed to obtain them. The experiment to be made was the combustion
of hydrogen with common air ; or, as it proved, its combination with
the proportion of oxygen which the common air contained. Now this
latter was then a quantity imperfectly known. Hence those analyses

which he made in 1781, of the atmosphere under all circumstances, at
diiFerent times of the day, in town and country, in summer and winter,
by which he determined its composition more accurately than any of
his contemporaries, and with a precision which has scarcely since been
exceeded : thus, with a knowledge of the specific gravities of the gases,
and of the weight of common air, he was in a condition to have com-
pared the correspondence of the weight of the gases consumed in the
combustion, with that of the fluid produced. But this experiment
had a weak side, in the practical difficulty of collecting the fluid : he
therefore took a more certain method of examining the question by
volume instead of weight, by ascertaining whether the production of
the fluid was accompanied by the total disappearance of the com-
bining gases : to a given bulk of atmospheric air, he added, in success-
ive experiments, a gradually decreasing volume of hydrogen gas, and
found a point at which the computed volume of oxygen entirely
disappeared. But there was yet a possibility of error : the fluid
produced might contain something besides water: he analysed it, and
found that the water was pure. Not yet satisfied, he repeated the ex-
periment in a simpler form, by burning the hydrogen with oxygen, in
place of common air ; and here a difference little to have been expected
appeared, for, on analysing the fluid he found it to contain not water only,
but nitric acid ; he traced the acid to its source in the small portion of
atmospheric air with which the gases chanced to be contaminated, and
inferred that the oxygen and nitrogen which it contains, unite under
certain circumstances to form nitric acid. Thus he was led to the dis-
covery of the cause of its diminution when traversed by the electric
spark, and from the residuary defect of the experiment he completed
the solution of the problem.

The experiment by which Cavendish had in 1781 ascertained the con-
version of oxygen and hydrogen into water, Priestley repeated in an
imperfect manner in 1783 ; and since it is this repetition which M.
Arago has mistaken for the first proof of the composition of water,
listen. Gentlemen, to Priestley's own preface to the account he
gives of it : " Still hearing," he says, " of many objections to the con-
version of water into air, I now gave particular attention to an expe-
riment of Mr. Cavendish's concerning the re-conversion of air into wa-
ter, hy decomposing it in conjunction with inflammable air" He then
relates the precautions he took in repeating this experiment, expresses
his wish that he had a nicer balance, and tells how he collected the
fluid by wiping the inside of the glass with filtering-paper; but it does
not appear, either from his own statement or the still more particulai-

one furnished by Mr. Watt, that he examined the nature of the fluid.
Experiments thus conducted could not, and did not, lead to any solid
conclusion ; Watt suspended his judgment upon them for a twelve-
month, and seven years afterwards, we find Priestley expressing
himself thus : " / must say, as I did v)hen I was myself a believer in
the decomposition of water, that I have never been able to find the
full weight of the air in the water produced by the decomposition."
And again : " Having never failed, ivhen the experiments were conducted
ivith due attention, to procure some acid lohenever I decomposed dephlo-
gisticated and inflammable air in close vessels, I concluded that an acid
was the necessary result of the union of these two kinds of air, and not wa-
ter onhj'^y Compare these statements, Gentlemen, which have stood on
public record for half a century, with those of M. Arago, affirming that
Priestley was the first who proved, and Watt the first who understood,
the conversion of air into water, and ask yourselves, how it is possible in
the face of such evidence to sustain a charge against Cavendish, Blag-
den, and the printers of the Royal Society's Transactions, of con-
spiring to steal a discovery thus acknoicledged to have been derived from
Cavendish, and of which the truth, recognised for a moment, was im-
mediately afterwards denied by Priestley, and doubted of by Wait.

In doing this justice to an injured name, I have been led to speak of
one whose numerous discoveries attracted in those daj^s the eyes of all
Europe to Birmingham, and who deserves to be admired not more for
his inventive fertility and indefatigable industry in experiment, than
for the honest candour with which he related every fortuitous success
and extraneous hint, and the liberal profusion with which he scattered
his gold abroad for public use, as fast as he drew it from the mine.
It has been one of the charges, Gentlemen, against this Association,
that an analysis of the character of Priestley formed a part of its early
transactions : that character, drawn by a hand no less judicious than
skilful*, regarded science alone, and contained not a single particle of
political or polemical alloy : if it had, being in the chair when it was
read, I should have felt it to be my duty to interfere. Much more
would I myself avoid the touching from this chair on any topic which
should have a tendency to excite feelings alien to our pursuits, and de-
structive to all social union : but whilst I can well bear to hear our
meetings upbraided with such faults as these, there is one point of attack
on which I think I ought not to be silent, even though it stands close
on the boundaries of those subjects which I would most rigidly exclude.

* The late Dr. Henry.

On my own judgement alone I should scarcely venture to meddle with
so arduous a question, did I not see those around me who desire it at
my hands, as required by the position in which the Association stands.

A century and a half ago the Royal Society met with opponents si-
milar to those whom the Association has to encounter now. " Their
enemies," says Dr. Samuel Johnson, " were for some time very nume-
rous and very acrimonious, for what reason it is hard to conceive, since
the philosophers professed not to advance doctrines, but to produce
facts, and the most zealous enemy of innovation must admit the gradual
progress of experience, however he may oppose hypothetical temerity."
They were assailed, Gentlemen, with jokes as well as libels ; but there
is reason even in ridicule ; and, on this subject, the irony of Butler
himself is forgotten ; but there was also a graver class of men in those
days, who saw in the establishment of the Royal Society injury to re-
ligion ; their names and publications have perished, but the memorial
of their apprehensions is embalmed by a Avriter* whose early history of
the Society has been described by his great biographer as " one of the
few books which selection of sentiment and elegance of diction have
been able to preserve, though written upon a subject flux and transi-
tory." — " I will now proceed," said the episcopal historian, " to the
weightiest and most solemn part of my whole undertaking, — to make a
defence of the Royal Society and this new experimental learning, in
respect of the Christian faith ; and I am not ignorant in what a slip-
pery place I now stand, and what a tender matter I am entered upon ;
I know it is almost impossible, without offence, to speak of things of
this nature, in which all mankind, each country, and now almost every
family, disagree. I cannot expect that what I shall say will escape
misrepresentation, though it be said with the greatest simplicity, while
I behold that most men do rather value themselves and others on the
little differences of religion than on the main substance itself." He
then thinks it necessary to employ thirty-three pages in defending the
inductive philosophy against the charge of impiety, and concludes with
this caution, — " that, above all, men do not strive to make their own
opinions adored, while they only seem zealous for the honour of God."

These are bygone days, and Time, Gentlemen, which seems to have
little effect in removing prejudice, makes great changes at least in cir-
cumstances : the philosophy thus early dreaded has since extended it-
self on every side ; science pervades our manufactures, and science is
penetrating to our agriculture ; the very amusements, as well as the

* Spratt, Bishop of Rochester.

conveniences, of life, have taken a scientific colour. In these altered
circumstances, were any now rash enough to kindle the dying embers
of this obsolete bigotry — to stir up a worse than civil war between the
feelings of piety and the deductions of reason, to go forth with the
" argumentum ad odium " for their only weapon, against a host of facts
patiently ascertained, and inferences fairly drawn ; — were they to call
in the Scriptures to supply their defects, and fasten on them their own
crude and ignorant speculations — were they to be seen shifting their
ground from one false position to another, all equally untenable, and
all assuming to be the sole defences of the true faith, — what would be
the natural consequence of a warfare at once so offensive and so hope-
less ? what the effect of so many baffled aggressions and self-inflicted
defeats ? what the fruit which the tree of knowledge would bear, thus
injured, in the name of religion, by men who should remove the
boundary marks of faith and philosophy, and confound things human
and divine ?

There are, indeed, certain common points in which reason and reve-
lation mutually illustrate each other ; but in order that they may ever be
capable of doing so, let us keep their paths distinct, and observe their
accordances alone ; otherwise our reasonings will run round in a circle,
while we endeavour to accommodate physical truth to Scripture, and
Scripture to physical truth.

The observation of the true points of accordance in such lines, is one
of the most instructive of all studies ; and when combined with an
honest observation of the discordances also, leads to important conclu-
sions.

There are many branches of inductive inquiry through which these
parallel lines may be drawn, and their accordances observed. Thus
Sir Isaac Newton has deduced from the history of inventions, the spread
of nations, and the present amount of population, that the time for
which mankind have existed cannot materially differ from that usually
assigned from Scripture. Geology, with less distinctness, points to-
wards the same conclusion. But there are lines of accordance and dis-
cordance within the Scriptures themselves. Now, in drawing these
lines for human chronology, we find discordances between different
versions of almost equal authority, and that to such an amount, that
while the Hebrew gives 1948 years for the epoch from the Creation to
Abraham, the Greek assigns for the same period 3334 ; and this differ-
ence of nearly 1400 years lies not in a single sum, but is divided among
successive generations. For the first seven centuries, the larger com-
putation was exclusively followed ; for the last four, the whole Western

Church has adopted the less. Do these discordances undermine the
authority of Scripture ? Do they shake — has any one imagined them
to shake — the substantial credit of its history of mankind? Yet it is
plain that, in its present condition, Scripture does not teach with cer-
tainty and exactness the computation of time. The book of Genesis is
not then a book of chronology : it is a book which, by a series of ge-
nealogies, traces back the various races of men to one common source.
Now, in this point, all the versions, and both the volumes of Scripture,
concur — to this point all the lines of scientific inquiry converge — the
analysis of language, the most legitimate conclusions of physiology and
natural history, coincide in the fact that the nations of the earth are of
one blood. There is nothing vague or doubtful in this. Reason and
religion are here in perfect accord.

Let us proceed from the history of mankind to the general philosophy
of nature. No one, I think, can doubt that those who condemned the
Copei'nican system were justified in conceiving that the Scriptures
speak of the earth as fixed, and the sun as the moving body. Every
one will allow also that this language is ill adapted to the scientific
truths of astronomy. We see the folly of any attempt, on this point,
to interpret the laws of nature by the expressions of Scripture : and
what is the ground of our judgement ? We are not all competent to
judge between the theory of Copernicus and those which preceded it ;
but we determine against the seeming evidence of our senses, and
against the letter of Scripture, because we know that competent persons
have examined and decided the physical question. Now, Gentlemen,
in Geology xoe are arrived at the selfsame point ; that is to say, a vast
body of the best-informed naturalists have examined, by all the various
lights of science, and by undeniable methods of investigation, the struc-
ture of the earth ; and however they may differ on less certain points,
they all agree in this — that the earth exhibits a succession of stratifi-
cation, and a series, of imbedded fossils, which cannot be supposed to
have been so stratified, and so imbedded, in six days, in a year, or in
two thousand years, without supposing also such numerous, such con-
fused, and promiscuous violations of the laws and analogies of the uni-
verse, as would confound, not the science of geology alone, but all the
principles of natural theology. Here, then, is another point of discord-
ance : and in both these cases the discordance lies between the language
of Scripture and the truths of science.

To understand how this may be explained, let us compare the ac-
count of creation given in Genesis with that contained in a composition
as old, or older, than this oldest of books, — a composition which, car-

rying us back some four thousand years into the midst of the patri-
archal ages, yet breathes a spirit of no vulgar philosophy ; and when
it speaks of Him " who hangeth the earth upon nothing," who " maketh
a weight for the winds, and weigheth the waters by measure," might
tempt us to seek here, with Hutchinson, for the true system of the uni-
verse. In that book, I say, we have the first account of the creation of
the world, proceeding, as it were, from the mouth of the Creator him-
self. " The Lord answered Job out of the whirlwind, and said. Where
wast thou M'hen I laid the foundations of the earth ? declare if thou
hast understanding. Who hath laid the measures thereof, or who hath
stretched the line upon it, whereupon are the foundations fastened, or
who laid the corner-stone, when the morning stars sang together, and
all the sons of God shouted for joy ?" " Or who shut up the sea with
doors, when it brake forth as if it had issued from the womb, when I
made the cloud the garment thereof, and thick darkness its swaddling
band, and brake up for it my decreed place, and set bars and doors,
and said hitherto shalt thou come, and no further, and here shall thy
proud waves be staid ?"

Take, then, these " thoughts that breathe and words that burn," and
compress them if you can into some true or some fanciful system of
science ; teach us where to find " the house wherein darkness dwelleth,"
to " bind the sweet influence of the Pleiades, and loose the bands of
Orion"; explain to us, with respect to one of God's creatures, what the
natural process is by which he " drinketh up a river and hasteneth
not "; and of another, how " his breath kindleth coals, and a flame go-
eth out of his mouth," and then take credit to yourself for vindicating
the truth of Scripture : and when you have thus illustrated a compo-
sition, by the side of which, till you touched it, the images of Homer
and Pindar seem but as prose, go on — instruct us how to interpret that
other most ancient book, recorded, it has been thought, by the very
same hand — take that passage of it which drew forth the admiration of
heathen antiquity — borrow for your purpose the deepest thoughts of
modern science — substitute, " Let there be ether, and there was ether"
for " Let there be light, and there was light." Why does this altered
expression fall so flat upon the ear ? it is not like the flood of harmoni-
ous sound which some of you may have heard from this Orchestra
responding to the words — it is not like the words themselves, which
pour upon the mind at once all the beautiful irradiation and delightful
perceptions of light : and yet. Gentlemen, after all, you have not even
thus perhaps presented a pure scientific view of the act of creation ;
for when you have conceived this empyreal ether, this boundless and

all-pervading substance, which vibrates knowledge to our wondering
ken out of the unfathomable depths of space, are you prepared to take
here your stand ? may you not yet find other and still finer links be-
yond ? and if you should, must not the very form of expression, the
instantaneous connexion of the thing made with its Maker, — " He spake,
and it was created " — become as little scientific, as it is, to the under-
standing of all men, superlatively impressive and sublime?

You see, Gentlemen, what my meaning is. Had it pleased God to
endow the ministers of religious truth with supernatural knowledge of
the mysteries of nature, they could not have used that knowledge to
any practical purpose ; they could not have used it so as to carry the
truths they were commissioned to preserve, into the hearts and imagi-
nations of mankind ; and so entirely sensible were they themselves of
this, that on subjects thus passing the power of language, they not only
meddled not with any system of science, but passed over popular ideas,
and the common senses of words, to those highly figurative expressions,
which are best adapted to impress transcendental truth.

Who, then, would expect to find in Genesis the chronology or se-
quence of Creation ? who can think that he upholds the authority of
Scripture by literal constructions of such a history, by concluding from
them that the earth was clothed with trees and flowers before the sun
was created, or that the great work was measured by six rotations of
the earth upon her axis ? It scarcely needed the evidence of physical
or geological science to teach us that such a mode of interpreting the
sacred writings is utterly unsound : when the same author speaks of
man as created in the image of God, every one perceives that this is
one of the boldest figures which language can produce ; and in what
but a figurative light can we view the days of Creation ? what can we
find in such a description but this truth — that the six grand classes of
natural phcenomena were, all and each, distinct acts of Divine power,
and proceeded from the fiat of a single Creator'^

Here, Gentlemen, is a second instance of one of those great points
of accordance, where all the conclusions of human science coincide
with revealed religion, and none more remarkably than that which has
been so falsely termed irreligious Geology ; for as Astronomy shows
the unity of the Creator through the immensity of space, so does Geo-
logy, along the track of unnumbered ages, and through the successive
births of beings, still finding in all the uniform design of the same
Almighty power, and the varied fruits of the same unexhausted good-
ness.

Thus, Gentlemen, we have seen in this comparison of two collateral

lines of knowledge, certain points of accordance, and certain points of
disagreement ; we have seen that Scripture furnishes us with no per-
fect chronology of history, and with no chronology of creation except
the creation of man ; but we find, also, that it does provide for us, and
has evidently aimed at providing for \is, from the earliest times to the
present hour, the knowledge of two facts : that all men are the children
of one human father, and the handiwork of one Almighty God. Here
the coincidence is perfect of every line within and without ; here the
philosophy of Job and Moses, of every prophet and evangelist, agree ;
here all the inductions of every branch of science mark the same cor-
responding points.

And what, Gentlemen, is the common quality of these two facts ?
Are they not the very facts on which the system of human duty sub-
sists, on which humanity and piety depend ?

These truths, nursed for a thousand years in the ancient Scrip-
tures of the Jews, led forth into new day, and with new accessions
of the same kind of knowledge by our holy religion, have walked
through the world, and been believed alike by the ignorant and the
wise, before our sciences were born : and here observe the methods
and the course of Providence ; — how, as in process of years, the current
of traditionary belief runs weaker, — how, as the advance of human in-
tellect looks for other kinds of proof, the arts and sciences come in to
support these essential truths : printing gives them stability and ex-
tension ; optics and astronomy pour in an infinity of evidence ; compa-
rative anatomy brings up its convictions, and geology subdues the
sceptical mind with hitherto unimagined demonstrations.

And now, Gentlemen, I think we are in a condition to draw an in-
ductive conclusion, and even to hazard a prediction. We may safely
predict, that truths thus firmly established by evidence, will never
be shaken by the researches of that reason which has hitherto lent
them all its support ; we may clearly point to that sacred ground
on which no unhallowed hypothesis should tread ; we are entitled, by
the rules of our art, to say to the misnomered philosopher who rashly
invades this territory, — These are settled points, settled by every con-
clusion of the intellect, as well as by every intuition of the heart :
stand aloof! disgrace not the name of Science by throwing stones at
the Temple of Truth. But for this assembled body of real work-
men, amidst their labours of intellectual industry, — the quarrier of
the stone, and the fine carvers thereof; the miner that digs the ore,
and the smith that fashions it in the fire — for all who are employed
on this sacred building, we are justly entitled to claim, that they shall
B 2

'not be forced, like the builders of another temple, to work with arms
in their hands — we are bound to wish them God speed : it is our duty,
our pride, and pleasure, each in our degree, to aid their efforts, and
animate their zeal. Go on, and prosper. Gentlemen, amid the best
wishes of the wise and good ; look well on the beauty of the fabric you
are adorning, and mark its substantial utility ; see piety kneeling at its
altar, and human infirmities crowding to its gate. With such thoughts
within, and such sympathies without, strengthen and regale yourselves
amidst your toils, and remember that they carry with them a far higher
reward than any human sympathy, in the approbation and the blessing
of the great Father of Truth.

POSTSCRIPT.

I have taken notice in the foregoing address, that the eloge of
Watt, delivered to the French Academy by one of its secretaries, and
subjoined to the Annuaire for 1839 published under the authority of
the Bureau des Longitudes, is blemished by statements which reflect
unjustly on the character of one whose memory is cherished among us,
as a bright example of the union of modesty with science, of the purest
love of truth, with the highest faculties for its discovery, and the most
eminent success in its attainment.

Perceiving these statements to be founded in mistake, I took the
earliest opportunity of rectifying them, at the meeting of the British
Association which followed within two or three weeks after I became
acquainted with them, rejoicing that I had it in my power, from the
position in which I had the honour of being placed, to make the cor-
rection of the error as formal and public as its promulgation had been ;
and persuaded that M. Arago, as soon as he should be fully possessed
of the facts, would consider it a duty which he owed both to the Aca-
demy and to himself, to retract the suspicions which he had expressed.

I regret, however, to find that I have not as yet succeeded in stating
the case with sufficient clearness to satisfy him, and that he continues
to maintain before the Academy* the correctness of his views, corro-
borating them at the same time with the additional authority of M.
Dumas. M. Arago says, that the account I have given of the disco-
very of the composition of water is incomplete (tronque), and I feel it
to be due to him to supply what may have been wanting in it, and to
furnish him with such evidence as can no longer leave any doubt upon
his mind.

* C'mptrs 7'evchs for January 20, 1840, p. 109, No. 3.

The proofs wliicli I have already alleged, that Cavendish owed
nothing either to the experiments of which Priestley sent an account to
the Royal Society, on the 21st of April 1783, or to the conclusions
which Watt drew from them, were these —

1. The experiments which Cavendish made in the summer of 1781
not only necessarily involved the notion (which is the claim set up for
Watt), but substantially established the fact (which is the claim set up
for Priestley) of the composition of water.

2. The experiment which Priestley made in April 1783, /or the pro-
fessed purpose of verifying the fact of the co7iversion of air into water,
communicated to him hy Cavendish, added nothing to the proofs which
Cavendish had already obtained of it nearly two years before.

3. Whilst the views of Cavendish are shown by the internal evi-
dence of the experiments themselves, and the train of reasoning which
they imply, to have been from the first precise and philosophical, those
of Priestley and Watt were always, as regards the former, and till after
the publication of Cavendish's and Lavoisier's papers, as regards the
latter, vague and wavering to a degree scarcely comprehensible to
those who have not studied the ideas prevalent at that period of chemi-
cal history.

These three positions I hope now to establish in a manner which will
leave M. Arago nothing more to desire.

The opinion of Watt has been called a theory, a doctrine, and even
a hypothesis; and a northern critic*, who views this question of indi-
vidual justice as one of national honour, allows the claim of Cavendish
to the proof of the fact, but reserves for Scotland the credit of the
Jtypothesis. So far, certainly, as it involved the theories of heat and
phlogiston, it ivas a hypothesis ; but so far as it related to the conver-
sion of inflammable and dephlogisticated airs into water, it was simply
an opinion that Priestley had succeeded in proving the point which he,
after Cavendish, had made an experiment expressly to ascertain.

Whatever it be called, however, whether a statement of the result
of Priestley's experiment, or a hypothesis, or a doctrine, or a theory,
it was no sooner conceived than placed by Watt on the shelf, and
left there from April to November : the experiment of Priestley also
remained in abeyance. Priestley has given reason enough for his not
prosecuting so important an inquiry further, by informing us that it
belonged to Cavendish : Watt has also assigned a reason for his sus-
pense ; and T have shown in my address, that that reason proves him

* Edinburgh Review, No. 142.

to have had no clear conception of the composition of water as consist-
ing of oxygen and hydrogen : it proves that with him hydrogen and
phlogiston were not convertible terms. In this I am sure MM.
Arago and Dumas will agree with me, whenever they shall take the
trouble to compare with attention Priestley's paper on " the Seeming
Conversion of Water into Air," and Watt's reference to that paper
in the preface to his letter to M. de Luc. The following is his own
account of his theory. " I first thought," he says, " of this way of
solving the phsenomena, in endeavouring to account for an experi-
ment of Dr. Priestley s wherein water appeared to be converted into
air ; and I communicated my sentiments in a letter addressed to
him, dated April 26, 1783, with a request that he would do me
the honour to lay them before the Royal Society ; but before he
had an opportunity of doing me that favour, he found, in the pro-
secution of his experiments, that the apparent conversion of water into
air by exposing it to heat in porous earthen vessels, was not a real
transmutation, but an exchange of the elastic fluid for the liquid, in
some manner not yet accounted for : therefore, as my theory was no
longer applicable to the explaining these experiments, I thought proper
to delay its publication, that I might examine the subject more delibe-
rately.'' Now, what were these experiments on the apparent conversion
of water into air? We learn from Priestley's paper, that he obtained
from the distillation of water in a porous earthen retort, a constant
supply of " air of the same purity as the atmosphere," so long as there was
free access of air to the outside of the retort ; and, " since," he says,
" pure external air was necessary to procure good air, it was concluded
by many of my friends, and especially Mr. Watt, that the operation of
the earthen retort was to transmit phlogiston from the water contained
in the [moist] clay [within the retort] to the external air*, and that the
water thus dephlogisticated was capable of being converted into respi-
rable air by the influence of heat." Here inflammable gas, or hydrogen,
is obviously out of the question ; the phlogiston of the water, which

* In the unpublished part of his letter. Watt states his views thus : — " On
considering the last and most remarkable production of air from water imbi-
bed by porous earthen vessels, the only case wherein it appears almost incon-
trovertibly that nothing was concerned in the production except water and
heat, I think that the earth of the vessel attracts the phlogiston from the water
and gradually conveys it from particle to particle until it transmits it to the
external air, which it probably phlogisticates." " I omitted to mention in its
proper place, that clay when made hot has a very powerful attraction for
phlogiston, and under some circumstances, becomes quite black with it ; but
Tcadily parts with it to pure air and becomes white again."

passing through the retort, is presumed to phlogisticate and vitiate
the external air, is 7iitrogen ; and the dephlogisticated air of the water
is supposed to retain sufficient phlogiston to make, with the assistance
of heat, good air, of the same purity as the atmosphere.

Such was Watt's " theory " and " way of solving the phaenomena,"
in April 1783. But Priestley, though he did not prosecute Cavendish's
experiment on the conversion of inflammable and dephlogisticated air
into water, went on with his own on the conversion of water into com-
mon air, and discovered that instead of a decomposition of water it was
only a transmission of air through the pores oj the retort: and therefore
it was, because the proof had failed of the convertibility of water into
dephlogisticated air, and the phlogisticated air now called nitrogen, that
Watt laid aside his theory as not borne out by the facts, till assured by
the papers of Cavendish and Lavoisier, that the form in which water
did contain phlogiston, was solely that of injlammahle gas.

But even after the publication of their luminous views, the ideas of
Watt remained equally vague ; for, in his " Thoughts on the consti-
tuent Parts of Water," printed in 1784, he says, "It appears that in
some circumstances dephlogisticated air can unite in certain degrees
with phlogiston without being changed into water. Thus Dr. Priest-
ley has found, that by taking clean filings of iron, which alone produce
only inflammable air of the purest kind, and mercurius calc.per se, which
gives only the purest dephlogisticated air, and exposing them to heat
in the same vessel, he obtained neither dephlogisticated nor inflamma-
ble air, but, in their place, fixed air*. Phlogisticated air seems to be
another composition of phlogiston and dephlogisticated air ; but in what
propox'tion they are united, or by what means, is still unknown. It
appears to me, that fixed air contains a greater quantity of phlogiston
than phlogisticated air does, because it has a greater specific gravity,
and because it has more affinity with water." He afterwards adds,
— "by some experiments of Dr. Priestley's, charcoal, when freed
from fixed air, and other air which it imbibes from the atmosphere, is
almost wholly convertible into phlogiston-\y Does M. Arago think that
one who had so confounded together hydrogen, nitrogen, and charcoal,
that with him either was as likely as the other to foi/U vater, was in a
condition to discover its composition, or to throw any light upon the
subject ? Cavendish, indeed, has shewn that it was possible to reason

* Cavendish had already pro^'ed by an experiment related in the Philoso-
phical Transactions, vol. Ixxii. part 1, that Priestley was mistaken in this, and
that the fixed air was owing to carburet of iron (plumbago) in the iron filings.

t Phil. Trans., vol. Ixxiv. part 2, pp. 334, 351.

well on the phlogistic hypothesis, but not with ideas so loose and in-
definite as these*.

I am sorry to observe that my meaning has been so far mistaken,
as that I should be supposed to have imputed to M. Arago a wilful
misrepresentation of the words of Watt : I know him to be incapable
of any such intention. It is not bad faith that I complain of in this
substitution, but want of sufficient care in stating and deciding a ques-
tion of which the decision involved so severe a censure ; and I do not
despair of convincing both M. Arago and M. Dumas, who, after having
"attentively examined the argumentation of his colleague," and having,
like him, "scrupulously studied" the correspondence of Watt, preserved
at Aston Hall, " adopts completely, and in all its parts, the history
which M. Arago has written of the composition of water f;" that there
are still more cogent proofs of the inexpedience of this substitution,
and that in 1783 Watt and Priestley were almost as little acquainted
with the distinctive properties of the gas which we call hydrogen, as
they were with the word.

Though I have not had the advantage of studying the unpublished
MSS. of Watt, I know that they loere submitted to the inspection of
the late Dr. Henry, with whose reputation as a pneumatic chemist
M. Dumas is well acquainted, and whose knowledge, acuteness, and
candour were such as eminently qualified him to judge in such a ques-
tion; and I learnt from Dr. Henry that these MSS. produced no change
in his opinion as to Cavendish's title to be considered the first disco-
verer of the composition of water. Had M. Dumas examined the
account of the experiment which M. Arago quotes from Priestley's

* Priestley never extricated himself from the confusion arising out of these
indistinct conceptions ; in speaking of an experiment in 1785, he says, " the
water must have been so far altered as to be changed into fixed air, which
will be thought not to be any great paradox, if it be considered that, accord-
ing to the latest discoveries, fixed air and water appear to consist of the same
ingredients." Afterwards, we find him doubting whether inflammable gas and
dephlogisticated air ever form water, and conceiving that they do form phlo-
gisticated air and nitric acid (Phil. Trans., vol. Ixxxi, 1791) ; and in his Lectures
on Experimental Philosophy in 1794, he says (p. 44), " It has of late been
thought that water is resolvable into dephlogisticated and inflammable air ;
but the experiments which have been alleged to prove this do not satisfy me ;
so that for any thing that appeared till very lately, water might be considered a
simple element : by means of heat, however, it seems to be resolvable into
such air us that of which the atmosphere consists, viz., dephlogisticated and
phlogisticated, only with a greater proportion of the former."

t Comptes rendus, p. 111.

paper, with the same care which he has devoted to the correspondence
of Watt, he would probably have come to the same conclusion ;
at all events he would not have failed to observe one circumstance in
it, which would have rendered my statement that Priestley never found
the weight of the water equal to the sum of the weight of the gases, less
*' inconceivable " than his colleague represents it : he would even have
found it possible to demonstrate with some degree of certainty the
minimum of the deficiency.

Priestley, though he says nothing of the weights or volumes of the
gases which he burnt, any more than he does of the weight or nature
of the fluid which he collected, mentions one circumstance very mate-
rial to a due estimate of the value of his experiment : he tells us the
means employed by him to obtain his gases pure and dry. He ob-
tained, then, his oxygen from nitre, and his inflammable gas from the
distillation of well-burnt charcoal. No one knows better than M. Du-
mas the products of such a distillation. There is reason to think that
if charcoal be well burnt, and so dry that the vapour to be decomposed
is small in quantity, and the heat at which it is decomposed strong,
the whole product of such a distillation would be carbonic oxide and
hydrogen, in equal volumes, each volume of the hydrogen evolved
from the water in contact with the ignited charcoal corresponding to
half a volume of oxygen, and that half-volume producing one volume
of carbonic oxide. In this case, if we call the weight of the hydrogen
1*, the weight of water formed in burning it is 9*: the weight of
hydrogen and oxygen gas burnt is also 9* ; and the weight of car-
bonic oxide forming the other half of the distilled gas, is 14*1 ; and
this requires for perfect combustion 8 of oxygen — together = 22'1,
which added to 9 = 31*1 ; 5o thai the weight of icater formed in burn-
ing such a mixture is to the weight of the gases burnt as 9 : 31 '1.

But this theoretical result has never been experimentally demon-
strated*. In the experiments that have been actually made, in which no
particular attention has been paid to the heat at Avhich the decompo-
sition is effected, part of the carbonic oxide is replaced by carbonic
acid, and part of the hydrogen combines with carbon. Henry analysed
this mixed gas in 1808, and found that 100 volumes, freed from the
carbonic acid, required 60 of oxygen for perfect combustion, and gave
35 of carbonic acid. I shall presently have occasion to mention, that
Cavendish's unpublished experiments, made in 1783, furnish nearly the

* Cruikshank's experiments, giving, as computed by Henry (Nicholson's
Journal, vol. xi. p. 71), 43 measures of carb. oxide in 100 of the gas, ap-
proach nearest to the theoretical composition.

same result; and when Priestley in 1785* detected the difference be-
tween the gas distilled from charcoal, and pure hydrogen, he arrived,
as to the quantity of carbonic acid, at a similar conclusion ; in this
case we maj^ consider the mixture as containing 65 volumes of hydro-
gen, 6'66 of carburetted hydrogen, and 28*34 of carbonic oxide (in
addition to 25 of carbonic acid) ; and it will be found, on calculating the
results of burning such a composition, that the weight of the water
formed is to that of the gases burnt, as I :2.

It is manifest therefore that Priestley could not possibly, even if he
had used a better method of collecting the dew, than wiping the sides
of the glass, have found the weight of the water equal, as MM. Arago
and Dumas suppose, to that of the gases which he burnt, nor to half
that weight ; it is manifest also, that he did not weigh the gases, either
before burning or afterwards, nor take their specific gravity, but esti-
mated them on the erroneous supposition that all inflammable gases
are alike. Watt was in the same error; and it was in consequence
of this error, that in his letter to De Luc, notwithstanding the notice
Cavendish had given that " the air from charcoal is a different kind of
inflammable airf," he states, on the authority of Priestley, that " charcoal
is almost wholly convertible into phlogiston J." Thus do we find that
Protean name bestowed pro hac vice on a mixture of gases probably
not containing more than -^^ or y^j of its weight of hydrogen. — '' Et
voila," as Berthollet said of a subsequent experiment made with no
greater accuracy, "a quoi ce reduit cette farneuse experience de M.
Priestley, dont les resultats avoient ete si bien prevus et analyses par
M. Cavendish §."

Cavendish, as early as 1766, or very soon after, had discovered
that there was more than one species of inflammable gas : his Phlo-
giston therefore tvas hydrogen and nothing else ; whether obtained from
zinc or iron, he knew that it had a constant specific gravity, and he
found that it had likewise a constant combining quantity ; if he had
not attended to these points, he could neither have experimented, or
speculated, on the composition of water to any manner of purpose.

* " Expending 94 grains of perfect charcoal (by which I mean charcoal made
with a very strong heat, so as to expel all fixed air from it), and 240 grains of
water, I procured 840 ounce measures of air, -\ of which was fixed air, and of
the inflammable part nearly ^ more appeared to be fixed air by decomposition."
(Phil. Trans., vol. Ixxv. part 1, p. 194, 1785.)

t Phil. Trans., vol. Ixxiv. part 1, p. 135.

X Ibid., part 2, p. 351.

§ Consid. sur lesExper. de M, Priestley, relatives a la Compos, de I'Eau.
Annales de Chimie, torn. iii. p. 86.

In process of time Priestley also discovered that the gas produced in
the distillation of charcoal was widely different from that evolved in
the solution of metals ; and hence his subsequent assertion that he "had
never been able to find the full weight of the air decomposed in the
water produced by the decomposition," was more relevant to this ques-
tion than M. Arago is aware. Priestley knew that the experiment
which M. Arago has recalled into notice, was erroneous in all its parts ;
and as it could tend only to mislead, when he reprinted in 1790 the
paper which had contained it, he exercised a sound discrimination, and
whilst he retained the account of those experiments in which he ima-
gined that he had converted water into common air, as, though erro-
neous, containing something instructive, he omitted this as utterly
worthless. It remains for MM. Arago and Dumas to follovv his
example of candid retractation, and restore the experiment, with the
claims that have been founded upon it, to the grave from Avhence it
has been disinterred.

Having now disposed of two of the points on which I promised to
satisfy M. Arago, namely, the worth of Priestley's experiments on the
composition and decomposition of water, and of the deduction from
them of the theory, doctrine, or hypothesis of Watt, (except, indeed,
so far as M. Arago may coincide with my friend Lord Brougham in
thinking Watt's introduction of the matter of heat an improvement on
the views of Cavendish)*, I now turn to the real history of this great
discovery, to which, since the meeting of the Association at Birming-
ham, I have been enabled to make an addition that cannot fail to ex-
cite the interest of all who pay attention to experimental science.

It is one of the privileges of genius to give duration even to its
perishable remains. In the expectation that I should find the MSS.
of Cavendish still in existence, I applied to Lord Burlington for in-
formation, and found that they had passed into the hands of his grand-
father, Lord George Cavendish, and thence to the present Duke of
Devonshire, from whom I have obtained permission to use them for
the elucidation of the present question.

These carefully preserved MSS. exhibit the footsteps of a mind

* Had Watt remarked only that there was here another instance of the
general fact, that whenever a combination is formed of greater density than
the combining bodies, heat is generated, the remark would have been just and
obvious ; but in representing the phsenomena as influenced by chemical affini-
ties of heat, and stating that " dephloyisticated water has a more powerful at-
traction for pJdoyiston than it has for latent heat" (Phil. Trans., vol. Ixxiv. p.
334), he introduces a principle which chemistry has no means of investigating.

that had travelled over the whole range of natural philosophy, and they
are impressed with many striking marks of undisplayed knowledge,
and of that indifference to fame which in England is well known to have
been a prominent feature in the character of Cavendish, of whom
it has been handed down to us that " he * was peevishly impatient
of the inconveniences of eminence, detested flattery, and was uneasy
under merited praise." The same negligence of publicity belonged to
the characters of Newton, Black, and Cavendish, and their claims to
their greatest discoveries have only been substantiated by the interpo-
sition of their friends.

What curious facts of this kind appear in the parts of these MSS.
which relate to mechanical, meteorological, magnetical, and electrical
subjects, I must leave to the examination of others; but I will mention
those which have occurred to me in looking over the chemical and
geological papers.

The name of Cavendish has never been mentioned among geologists,
and I apprehend that it will occasion some surprise to those who have
most studied the history of geology, to learn that in journeys of the
date of 1787 he ascertained, in company with Blagden, by his own
personal observations, assisted by those of an almost equally unnamed,
but most acute and comprehensive observer, Mitchell, the entire se-
quence of all the great beds of English stratification, traced by their
mineralogical character, position, and dip, from the beds above the
chalk down to the slate-rocks.

At a period when nothing had been published on the subject of
latent heat, and the knowledge of Black's discoveries scarcely extended
beyond the students of his class at Glasgow, we find Cavendish, with
no other information respecting them than the report of a single factf,
deducing all the laws of the generation and destruction of heat which
attend the conversion of elastic fluids into liquids, and liquids into
solids, from an independent and elaborate series of experiments which
the world has never heard of, adhering, as in his subsequent investi-
gation of the composition of water, to the Newtonian theory of heat,
and denying it that materiality and combining property which has
marked, down to the present day, the speculations of the school of
Black. These experiments include determinations of the specific heats

* Brand's Preface to Supplement to Encycl. Brit.

f This fact was, that " in distilling water or other liquors, the water in the
worm-tub is heated thereby much more than it would be by mixing with it a
quantity of boiling water equal to that which passes through the worm." —
See Appendix, p. 47.

of a variety of substances, such as wax, spermaceti, and mercury,
with other metals, and metallic alloys, antecedent by sixteen years to
the first published, which I apprehend were those of Wilcke in the
Stockholm Transactions. The same MSS. contain also determinations
of the tension of vapour at low temperatures in the barometrical
vacuum, and an experimental demonstration, and theory, of that excess
of temperature in freely boiling water above the heat of steam, on
which observations have since been made by M. Gay Lussac and others.

The portion of the MSS. which belongs more directly to chemistry
is small, with the exception of the experiments on air, but not less re-
markable as regards unpublished labours and hidden treasure. In
this point of view is to be considered a series of experiments on arsenic,
which bears the date of December 1764, and had been preceded only
by the experiments of Macquer on its neutral salt. At that early period
Cavendish had discovered the acid of arsenic *, had ascertained the re-
lation in which it stands to the oxide and the regidus, and had examined
the salts ivhich it forms, with at least as much accuracy as Scheele, in
the well-known experiments which he published in 1775 ; this treatise
has been twice transcribed by Cavendish from the original notes, in
the form of a communication to a friend, and is in a state fit for the
press ; nor can I conceive any reason for the suppression of experiments
of so much value, but that which the character ascribed to him by his
friends suggests.

Among these arsenical experiments appears the first statement of the
nature of nitrous gas, as he afterwards described it in his paper on fac-
titious airs in 1766, and which was the legitimate statement, till the
phlogistic hypothesis was discarded: he had observed also the distinction
between nitrous gas and nitrous acid vapour, but was unable to assign
the reason of the difference. It further appears from a manuscript
among his early papers on factitious airs — on which he has written
" Communicated to Dr. Priestley " — that Cavendish was the first who
distinguished nitrogen from other kinds of unrespirahle and incom-
bustible gases, and proved by experiment that atmospheric air consists
of two parts, one of which in the combustion of charcoal is converted
into fixed air, whilst the other is a mephitic gas sui generis : Priestley, in
a paper in the Philosophical Transactions for 1772, mentions this com-
munication, but has not stated correctly the conclusions which it con-
tains.

As remarkable an instance as any which I have observed of Caven-
dish's habit of keeping discoveries in abeyance, especially such as he
* Appendix, p. 52.

had not completed to his entire satisfaction, is to be found in a MS.
constituting a " Mh part " of liis celebrated experiments on factitious
air. This unpublished paper, written for the Royal Society, probably
in 1766 or 1767, and consisting, with a "digression on air" which
accompanies it, of twenty-six pages, commences with a series of expe-
riments on the air produced from animal and vegetable substances in
distillation, the animal matter employed being hartshorn shavings, the
vegetable substances, wainscot and tartar: the inflammable gases
from these he finds nearly similar to each other, but so different in spe-
cific gravity, and explosive power, from the inflammable gas yielded by
metals, that he determines them to be of a different kind : he then
examines the caput mortuum of the distillation by deflagrating it with
nitre, and finding, contrary to expectation, that the weight of the fixed
air produced is greater than that of the charcoal consumed, leaves off
abruptly, in doubt whether the experiment is incorrect, or whether part
of the fixed air is to be ascribed to the nitre. We see from the state-
ment which I have mentioned as having been communicated by him to
Dr. Priestley before 1772, that by that time he had acquired clearer
ideas of the generation of fixed air.

From this account of experiments which Cavendish never chose to
publish, I pass to those of which he delayed the publication till he had
completed them, though in their progress he made no secret of them
to his friends. They fill a volume of unsewn and single, but paged and
indexed octavo sheets, in his own hand, bearing dates from February
1778 to May 1785, in the following proportions: in 1778 thirty-three
pages, in 1780 thirty-six, in 1781 seventy-five, in 1782 forty-five, in
1783 fifty-three, in 1784 forty-four, in 1785 thirty-three. I found
them in a packet entitled " Experiments on Air."

These very numerous and laborious experiments all bear on the so-
lution of one question, namely, what becomes of the lost air in the va-
rious chemical processes, in which it is now known that oxygen passes
into fixed combinations? Scheele in 1777* had stated this question
thus : " It appears in the transition of what is called injiammahle prin-
ciple into the air a considerable part of the air is lost. But whether
the phlogiston which is lost from the substance still remained (in his
before- mentioned experiments) in the residuum of air in the bottle, or
whether the lost air was united and became fixed with the substances of
liver of sulphur, oils, &c., is a question of great importance. It would
follow on the first supposition that phlogiston has the power of de-

* Scheele's work on air was written in 1775, but not published till 1777-

priving air of part of its elasticity, and that for this reason it is more
compressed by the external air. In order to extricate myself from these
doubts I first supposed that such air ought to be specifically heavier
than common air, both on account of the i!)hlogiston it had gained, and its
greater density. But how great was my astonishment upon finding that
a very thin retort filled with this kind of air and Aveighed in the nicest
manner, was not only not heavier than an equal measure of common
air, but even somewhat lighter ! I then imagined that the last suppo-
sition might be applicable, and then it would follow that the lost air
might again be separated from the materials employed in the experi-
ment." With this view he tries whether " the lost air had not been
changed into fixed air," and failing in finding any, as the next resource,
alludes to the idea that " the phlogiston when united with this air
might make it less ponderous ;" " however, since phlogiston," he adds,
"is a substance (which always supposes some weight), I very much doubt
whether this hypothesis is founded on truth ;" and he concludes at last
by saying, " I will prove that by union of air [oxygen] with the inflam-
mable principle (phlogiston) a compound is formed so subtle as to pass
through the fine pores of the glass and disperse all over the air." This
subtle compound Avas the matter of heat and light : in the shape of these
incoercible and imponderable agents, oxygen, and the elements which
enjoyed the title of phlogiston, became free to pass to and fro
unquestioned ; and thus Scheele cut the knot which he was not able to
untie. He afterwards informs us that " this generation, or new com-
position of heat and light by an union of air of fire with more or less phlo-
giston, obtained" not much applause ; " but could I," he adds, "naturally
conclude otherwise, when I saw a mixture of air of fire and inflamma-
ble air after its explosion totally disappear, but that the fire air, when
united with the inflammable, must have penetrated through the glass ?
because nothing could be observed on the outside of the glass in which
the explosion was effected but heat and light ; also in the water over
which it was effected in close vessels, notwithstanding I varied the ex-
periment in different ways, I could perceive nothing uncommon." " I
had often burnt a mixture of dephlogisticated and inflammable air, and
have always observed a dew in the glass immediately after the explo-
sion ; but I believed that air always contains some moisture and that
the inflammable air might also contain some moisture from the vi-
triolic acid, nay, that even the flame of the candle may yield some
dampness*."

* Crell's Chem. Annals, 1785, vol. i, part 3, p. 229.

S4.

Pi'ecisely the same difficulties had been previously felt and remarked
by Priestley*, and he had sought for a partial solution of them in the
precipitation of carbonic acid which had occurred in some of these
processes, and its absorption by the liquid over which the diminished
air was confined. This was the prevailing opinion of the cause of the
diminution ; Bergman, Kirwan, and other eminent chemists adopted it,
paying little attention to the new views of Lavoisier, who already in
1776 had found the key by which these phsenomena were ultimately
to be interpreted, and had succeeded in deciphering many of them :
but Lavoisier had at the same date deduced from too narrow an in-
duction the theory which so long continued to prejudice the chemists
of his school, that oxygen is the principle of acidity, and was unprepared
in consequence to conceive that it could be one of the constituents of
waterf .

In this state of the subject Cavendish took up those parts of the
problem which Lavoisier had not already sufficiently solved : he began,
in 1778, by ascertaining that when nitrous gas is mixed with oxygen or
common air, no carbonic or vitriolic acid is produced, but, as Lavoisier
had said, nitric acid alone ; and he then commenced those eudiometrical
researches which were the foundation of all his subsequent discoveries.

In 1779 he appears to have intermitted his experiments ; but he re-
sumed them in 1780, and obtained in this year so complete a mastery
over the methods of analysing atmospheric air, as to have determined
the proportion of oxygen in it to be l^, at a time when Scheele and
Lavoisier supposed it to be ^, and Priestley nearly as much. By the
same means he had acquired also the power of detecting the small-
est adulteration of oxygen gas, and the amount of the impurity ; and
he came therefore, in July 1781, to the question what becomes of the

* In 1774 Priestley writes, " In what manner air is diminished by phlo-
giston, independent of the precipitation of any of its constituent parts, is not
easy to conceive ; unless air thus diminished be heavier than air not dimi-
nished, which I do not find to be the case. It deserves, however, to be tried
with more attention. That phlogiston should communicate absolute levity to
the bodies with which it is combined is a supposition that I am not willing to
have recourse to, though it would afford an easy solution of the difficulty."

f " L'analogie, dit il (Lavoisier, Mem. de I'Academie 1781, page 471),
ni'avoit parte invinciblement a condure que la combustion de fair inflammable
devoit egalement produire un acide. Mais M. Lavoisier a senti que toutes les
analogies doivent disparoitre devant des faits positives ; et qu'il y a, entre les
analogies les plus fortes et les faits, la difference qui se trouve entre les pro-
babilites et la certitude." — Consid. sur les Exper. de M. Priestley, par M.
BerthoUet (Annales de Chimie, torn. 3, 1789).

air that disappears in the combustion of dephlogisticated and of common
air, with inflammable gas, enjoying the peculiar advantage of a more in-
timate acquaintance with all the gases operated upon than any other
chemist possessed. Of the oxygen examined by so many chemical tests
he knew the quality, and the quantity, whether he used the air of
the atmosphere or obtained it from any other source, whilst his
constant employment of the test of specific gravity gave him an ac-
curate knowledge of the residual gas : he had ascertained also with
care the properties of inflammable gas, and even gone some way, in
1766, towards determining, by attention to the comparative loudness
of the explosion, the proportions in which oxygen and hydrogen most
perfectly combine*.

These observations may tend to diminish the surprise with which
the most skilful and experienced in such researches cannot fail to
be struck, when they observe the precision with which Cavendish,
as soon as Warltire's experimentf had suggested to his mind an experi-
mentum, crucis, to determine between the truth of Scheele's supposition
and the more probable explanation of what had become of the burnt
air, offered by the circumstance of the deposition of water, proceeded
without the loss, if I may so speak, of a single move, by a regular
gradation of six quantitive trials of explosive mixtures, to solve the
question. In the fifth or mean of these (MSS. p. 114) he found the
point at tvhich the entire volume of two of the gases disappeared, lea-
ving the entire volume of the nitrogen of its proper specific gravity
and proved by chemical tests to have parted with all its oxygen : the
bulk of two volumes of hydrogen and one of oxygen was gone, but

* Phil. Trans., vol. Ivi.

f It was not Warltire, but Volta, who first fired mixtures of hydrogen and
air by the electric spark. (See a letter from Volta to Priestley, dated Como,
Dec. 10, 1776. Priestley's Experiments on Air, 3d Ed., 1781, App. p. 381.)
In 1779 Priestley endeavoured to ascertain the relative proportions of phlo-
giston in nitrous gas and inflammable air/ "by the help," he says, "of that
ingenious experiment of Mr. Warltire's mentioned in the Appendix to my 3d
volume, p. 367, viz., burning inflammable air in a given quantity of common
air." "Of this curious problem, however [the proportions of phlogiston], I
obtained a more accurate solution from the mode of experimenting introduced
by that ingenious philosopher, M. Volta, who fires inflammable air, in com-
mon, by the electric spark, and consequently can determine the exact propor-
tion of inflammable decomposed in a given quantity of common air." Priest-
ley's skill in Eudiometry did not enable him, however, to come nearer the
truth than to find the proportion of common air dephlogisticated by inflam-
mable air as 2 : 1 .

their weight remained in the vessel: the conclusion therefore which
Cavendish drew was infallible, (being a necessary consequence of the
indestruction of matter) — " that when mixed in these proportions and
exploded, almost all the inflammable air and about ^ of the com-
mon air lose their elasticity, and are condensed into the dew which
lines the glass*."

The subsequent laborious comparisons instituted by the French phi-
losophers f between the absolute weight of the gas consumed, and the
weight of the fluid produced, added nothing to the certainty of this
proof of its composition, nor even to the accuracy of our knowledge of
the proportion of its constituent parts ; they took the only means from
which in such a method any accuracy can be expected ; operating with
immense quantities of gas, at great cost, with much expense of time
and toil, and taking all imaginable precautions, they yet never obtained
a weight of water exactly equal to that of the gases, though near
enough undoubtedly to satisfy those to whom such a mode of proof
was more familiar than that devised by Cavendish ; but every chemist
knows that the method of volumes, first introduced on this occasion by
him, is the proper method of pneumatic determinations.

Thus far had he advanced in the early part of July 1 781 (MSS.p. 1 13).
One more experiment, so contrived as to enable him to consume a large
quantity of the gases, sufficed to prove that the fluid condensed was
pure water ; and thus, on one of the latter Sundays of that month,
(MSS. p. 127, foot note,) the general fact of the composition of water
was completely established.

In August (MSS. p. 120) he examined by the test of similar expe-
riments whether there was any difference in the hydrogen furnished by
zinc, or iron, and found none ; he contrived also an instrument for mea-
suring the force of the explosions (MSS. p. 130), and appears to have
used it as a test of the identity and purity of the gases, as well as of
their combining proportions, though its indications were not precise
enough to induce him to mention it in his paper. In these experi-
ments on the force of explosion he employed oxygen as well as atmo-
spheric air ; and proceeding in September to collect the fluid produced
by the combustion, found on the 28th of that month, 1781, (MSS. p.
146,) that the fluid produced by exploding two volumes of hydrogen with
one of oxygen contained nitric acid.

* Phil. Trans. 1784, p. 128.

t The first proof which Lavoisier gave of the composition of water was the
same as that given by Cavendish ; and he deduced the equality of the weights
as a consequence or corollary from this proof.

This oxygen having been obtained from nitrate of mercury, he sup-
posed that the nitric acid might have been derived from the gas, and
therefore repeated the experiment with oxygen disengaged from red
precipitate by oil of vitriol ; but he still found nitric acid.

Such were the experiments made in 1781, " concerning the recon-
version of air* into water by decomposing it in conjunction with
inflammable air", which Priestley f and Cavendish | mention as having
been communicated to the former, and repeated in consequence by
him in April 1783.

In the following year, 1782, Cavendish made further experiments
on the analysis of air, and the tests of oxygen, and in October resumed
the investigation of the cause of the production of nitric acid in the
combustion of that gas with hydrogen : he now employed the oxygen
evolved by plants, under the action of solar light, with the same result ;
but varying the proportions of the gases (MSS. pp. 203-5.) dis-
covered that an excess of oxygen conduced to the production of the
nitric acid: he had probably before conjectured the cause of the phae-
nomenon,and in his next experiment, in January 1783, (MSS. p. 211,)
he added a little nitrogen to the excess of oxygen, and found the quan-
tity of acid still further increased ; but when he mixed nitrogen with
oxygen (MSS. p. 217,) in the proportions of common air, and exploded
either this mixture, or common air, with a quantity of hydrogen in-
sufficient to consume all the oxygen in it, the excess of the latter no
longer determined the formation of acid, but, as in his first experi-
ments, pure water was the result. Hence he came to the following con-
clusions — that when hydrogen is burnt with oxygen, slightly contami-
nated with nitrogen, and in excess, the excess of oxygen forms with
the nitrogen nitric acid§ ; but that when it is burnt with oxygen mixed,
as in common air, with a large proportion of nitrogen, the heat of the

* That Priestley by air, here means oxygen, which was often so called
x«T i^axnv, appears from his manner of repeating the experiment, and from
Watt's defective acknowledgement, (the only notice he takes of any of Caven-
dish's experiments,) " I believe that Mr. Cavendish was the first who disco-
vered that the combustion of dephlogisticated and inflammable air produced
moisture, on the sides of the glass in which they were fired." Cavendish does not
(as M. Arago says) insinuate, but states distinctly, and without contradiction,
that he mentioned to Priestley " all his experiments on the explosion of inflam-
mable with common and dephlogisticated airs, except those which related to the
cause of the acid found in the water." Phil. Trans, vol. Ixxiv, part 1. p. 134.

t Phil. Trans. 1783, p. 426. J Ibid. 1785, p. 134.

§ Experiments on Air, Phil. Trans, vol. Ixxiv. part 1. p. 139.
c 2

explosion is so much diminished, that though the affinities of hydrogen
and oxygen are sufficient to determine at that temperature the forma-
tion of water, the affinities of nitrogen and oxygen are not sufficient to
determine the production o^ nitric acid^.

These were the last and the only experiments which Cavendish ever
made on the combustion of hydrogen and oxygen ; he had completed
the investigation, and reverted no more to the subject. Few rough day-
books of experiments would tell their own tale with such certainty and
distinctness as these ; in few could the consecutive course of reasoning
be traced thus clearly from the experiments themselves : there cannot
remain a doubt on the mind of any one who reads them, that in January
1783 Cavendish had not only discovered the certain fact that oxygen
and hydrogen in definite proportions form water, but likewise the strong
probability that oxygen and nitrogen form nitric acid, two months be-
fore Priestley began to experiment, and Watt to speculate, on the no-
tice which Cavendish had given the former of the composition of
water, and four months before Lavoisier received from Blagden a
similar notice.

These experiments were followed by an analysis of the gas distilled
from charcoal, which it is probable from some expressions in his paper
he may have been led to make by the circumstance of Priestley's ha-
ving used this gas in repeating his experiments without noticing the
production of nitric acidf. The quantity of oxygen which he found
consumed in its combustion corresponds precisely with Dr. Henry's
determination ; the quantity of carbonic acid appears to be less, pro-
bably from his manner of estimating it, by weighing the carbonate of
lime precipitated, instead of measuring the gas. At the same time, that
is to say in September 1783, it appears from these MSS. that by burn-
ing nitre with charcoal, and effecting a total decomposition of the nitric
acid, he confirmed analytically his synthetical discovery of its composi-
tion.

In 1 784 he proceeded to investigate the diminution effected in air by
the electrical spark, and found, on examining the amount and product
of the condensation, not only a further confirmation of the composition
of nitric acid, but the means of discovering, by the same method of

* Experiments on Air, Phil. Trans, vol. Ixxiv. part 1. p. 134.

f " It is remarkable that neither of these gentlemen (Priestley and Lavoisier)
found any acid in the water produced by the combustion, which might pro-
ceed from the latter having burnt the two airs in a different manner from what
I did, and from the former having used a different kind of inflammable air,
namely, that from charcoal." Phil. Trans, vol. Ixxiv. part 1. p. 135.

volumes as before, the combining proportions of nitrogen and oxygen.
One of these experiments well illustrates the rigorous precision of his
chemical ideas. It is difficult to bring the whole of a given quantity
of nitrogen into combination by the electric spark ; in the preceding
experiments the proportion of that gas which had disappeared with the
oxygen had been observed ; but there was a residue ; and while that
remained Cavendish was dissatisfied with the evidence : we know ni-
trogen, he argued, only either by negative properties — that it does not
burn — that it does not support respiration, — or by the relative property
of its specific gravity : these properties cannot give an absolute cer-
tainty that it is not a mixed gas : its entire combination can alone
prove that it is unmixed ; he therefore devised an experiment by which
he contrived to convert the whole of the quantity operated upon into
nitric acid, and thus he established with respect to it, what he had esta-
blished before respecting hydrogen and oxygen, the fact of its sim-
plicity as a combining body. What I mean by its simplicity as a com-
bining body, will be understood by observing that he continues to use
just the same hypothetical language respecting nitrogen as before, and
still speaks of it as a compound of nitric add and phlogiston. On his first
discovery of the composition of water he had entrenched the old doctrine
of phlogiston in the only position which was any longer tenable : he
fought the same battle for it as was fought in later days for oxymuriatic
acid, and on the same grounds : as I have shown that whenever Caven-
dish used the term dephlogisticated air, oxygen may be safely substituted
for it, and whenever he uses the term phlogiston, hydrogen* may be
substituted for it, I am entitled to show the similarity of the reasoning
in these cases more distinctly by explaining it in modern terms : " As
dephlogisticated air \_oxygeny\ he argues, "is only water deprived of
phlogiston \_hydrogen'], it is plain that adding dephlogisticated air \_oxy-
gen~\ to a body is equivalent to depriving it of phlogiston \_hydrogen~\ and
adding water to it, and therefore phlogisticated air [nitrogen, supposed a
compound of dry nitric acid and hydrogen~\ ought also to be reduced to
nitric acid by being made to unite to, or form a chemical combination
with dephlogisticated air [oxygen'] ; only the acid formed this way loill
be more dilute than if the phlogisticated air was simply deprived of phlo-
giston [hydrogen] f-"

Thus did Cavendish, in deference to received opinion, speak of ni-
trogen as a compound, while at the same time he was taking pains to

* It is worthy of remark that Cavendish was the first chemist who identified
phlogiston with hydrogen. Phil. Trans, vol. Ivi. 1766.
t Phil. Trans. 1785^ p. 379.

prove that it enters undecompounded into composition with other bo-
dies. Having proved this, it would have been better if he had dropped
the term phlogisticated air : but though the language is hypothetical,
the ideas are precise : and with respect to hypothesis, a distinction must
be made between the art of communicating, and that of discovering
truth : I have noticed in my Address how important it is, for the sake
of clearness, and for the avoidance of prejudice, to discard from our
reasonings all hypothetical expressions, resting, like this of the sup-
posed combinations of phlogiston, on loose analogies. Nevertheless in
the mind of every discoverer a private reserve is made for the admis-
sion even of loose analogies, and for the idea that every body deemed
simple may prove to be compound; previous, for instance, to proof of
the composition of the alkalies, to have spoken in hypothetical lan-
guage of the oxide of potassium, would have been logically objection-
able ; but yet if Davy had not entertained the hypothesis, he would
never have made the discovery.

The remaining experiments in this manuscript, bearing dates of
1784—5, are almost entirely devoted to the combustion of charcoal and
of the gas distilled from it, in various ways, with common air, oxygen,
and nitre, the chief object of which seems to have been to ascertain
whether that body is a compound. The conclusions at which Caven-
dish arrived were, that it contains no nitrogen, but that there was rea-
son to suspect that it might contain some hydrogen.

His computation of the experiments which he had made in 1783 on
the gas distilled from charcoal is worthy of remark. It was not known,
till Cruikshank made the discovery in 1801, that carbon and oxygen
unite in other proportions than those which form carbonic acid ; nor
was it known, till Henry stated it in 1 805, that carbonic oxide, or oxy-
gen in any form, existed in the gas from moist charcoal. Cavendish
however deduced the last of these facts from his experiments ; he com-
puted this gas to consist of carbon, hydrogen, and water, stating the
water at such an amount, as fully to represent the amount of oxy-
gen in the gas*, and to account for the presence of free hydrogen
without the corresponding oxygen which would have been due to the
decomposition of water, he proposes two suppositions — " From this ex-

* It was probably from these experiments that Cavendish derived in part
his opinion before alluded to, that water is a constituent part of inflammable
air ; since it appeared to be so in that kind which is obtained from charcoal.
It is remarkable, that Cruikshank, after his discovery of carbonic oxide, should
have overlooked its existence in this gas, and like Cavendish, should have com-
puted the gas to contain water, in the proportion of 9 grains in 14§.

periment it should seem either that charcoal contains hydrogen, or else
that the charcoal after distillation contained some oxygen."

Speaking of the latter gas in this computation Cavendish uses all
the various terms, dephlogisticated air, pure air, and oxygen : I have
given in the Appendix a letter in which he assigns to Blagden his rea-
sons for disapproving of the introduction of a nomenclature entirely
new ; and unquestionably the term oxygen was open to the same ob-
jection with the old name of dephlogisticated air, as equally involving an
erroneous hypothesis : Cavendish shewed in his paper on air that oxy-
gen does not always acidify ; and it has since been proved that it does
not exist in all acids: he objected to the new language, that without
the advantage of being already understood, it involved, no less than the
old, theories which in the rapid progress of chemical discovery might
quickly be disproved : he thought the time for such a reformation of
terms not yet arrived : he was mistaken ; for with the new language a
new and more rigorous system of reasoning was introduced into com-
mon use, and by degrees chemists learnt from experience to correct
also their notions of nomenclature, and discovered that in expressing
undecompounded substances, the less significant is the name, the better
it serves the objects of science.

Having now concluded my analysis of the chemical contents of
these MSS., I think it right to enable every one to judge for himself,
by lithographing the whole of Cavendish's experiments on the composi-
tion of water, and by giving a few extracts from those on other subjects.
I request the attention of M. Arago in particular, and of M. Dumas
who has adopted his views, to a letter addressed by Cavendish in Fe-
bruary 1785 to the editor of the Journal de Physique*, which will show
them how incapable he was of falsifying dates, or attempting to reap
fame from the mistake of a printer. It is to be regretted that Watt did
not take equal care to prevent the propagation of such mistakes. When
Dr. Black's lectures were published after his death, with a dedication
to Watt, he would have done well not to have allowed the history which
is there given of the discovery of the composition of water to pass
without correction; almost every statement and every date in that
history is a mistake, and the effect of those mistakes is to give prece-
dence to Wattf. Independent of other errors, the whole experiment

* Appendix, p. 65.

t The following is the account of this discovery given in Black's Lectures
as edited by Robison, with a dedication to Watt, in 1803. The errors are
printed in Italics.

" Dr. Priestley was occupied with the examination of inflammable air, and

ascribed in this account to Cavendish, ivith its date of May 1783, is, from
the beginning to the end, as to its existence, and all its details, a fiction :
it is easy to conceive a confusion of recollection which might lead a
lecturer to substitute his own ideas of what an experiment might
have been for what it was, or to confound the experiments of dif-
ferent persons on the same subject, though this is scarcely excusable
where the statement is one professing to adjust their respective claims.
Let us suppose then such a confusion to have led to the ascrip-
tion to Cavendish of the experiments of the French chemists ; but how
shall we account for the particularity of the fictitious date of May 1783
for the time of Cavendish's discovery ? Cavendish had not said a word
about May ; he had said that the experiments which constituted his
claim to that discovery were made in the summer of 1781 ; he had not

tried the effect of almost every substance on it : he also tried the effect of the
electrical shock and spark. As he expected, he found that it was expanded
by it, but could not be inflamed by it in close vessels, unless mixed with com-
mon air. In this state it fired with a violent explosion. He was particularly
surprised at the great diminution of bulk, — finding that a mixture of one part
of inflammable air, and two of common air, might be made to contract into
half the bulk, and that it was now phlogisticated air. Having already dis-
covered the vital air, he fired a mixture of these, and found that when two
parts of inflammable air and one of vital air were exploded together, it collapsed
into almost nothing, or nearly the whole disappeared. Mr. Warltire, who as-
sisted in these experiments, observed that the inside of the vessel in which
the deflagration had been made, was always moistened with dew. Dr.
Priestley naturally ascribed this to moisture, which probably adhered to the airs
employed, as they were always produced in processes in which water in some
form or other was present. These experiments loere made about the year 1782.
[1781 is the true date both of the experiments really made by Priestley and
Warltire, which include no such fact as that alleged above, and those of
Cavendish here confounded with them.]

" My friend Mr. Watt had taken great interest in these experiments of Dr.
Priestley's, and communicated his opinion concerning them to M. de Luc, in
a letter dated April 1783. [The true date of the experiments, here confused with
those of 1781, is April 1783, that of the letter is Nov. 1783.] This letter is,
in part, a transcript of one written some months before to Dr. Priestley, with
a desire that it should be communicated to the Royal Society. [The true date
is April 1783.] In this he declares his opinion, that the water observed in
these experiments arose from the combination of two airs ; and savs that
water is the compound of dephlogisticated or vital air, and inflammable air,
deprived of their latent heats ; and that dephlogisticated air is water deprived
of its phlogiston (i. e. of the inflammable air), in an aerial form, that is, satu-
rated with the matter of light and heat. Dr. Priestley did not communicate
this to the Society, because (he says) some exjjeriments which he had made since

made a single experiment on the subject after February 1783. Why
then the date of May in that year? I know not, unless because Watt
claimed to have made the discovery in April 1783, and Lavoisier
claimed to have made it in June 1783 ; and therefore by the argument
fromkindness and country, which sometimes gains an ascendence over the
imagination and belief even of the wisest and most virtuous minds.
Cavendish inust have made his decisive experiment in the intermediate
month of 3Iay. There can be no doubt however that had these lec-
tures been printed during the life of their author, he would have taken
more pains, before he had published them, to ascertain the facts. Nor
ought it to be omitted, that in other parts of the volume the discovery
of the composition of water is assigned to its rightful owner, and that

he saw Mr. Watt, were directly contrary to this opinion. [Mr. Watt himself
withdrew the communication.] Dr. Priestley's experiments e-vcited the attention
of the Honouralle Mr. H. Cavendish, and recalled to his mind his own observation
of the moisture in the vessels in which he had exploded these two airs. [There is
no foundation for this statement.] These experiments had been begun in the
summer of 1781, and were continued from time to time, along with those by
which he had discovered the composition of the nitrous acid. He immediately
set about repeating the explosion of dephlogisticated and inflammable airs by the
electrical sparks ; and in May 1783, he found that when six parts by weight of
pure dephlogisticated air were exploded with one of inflammable air, they dis-
appeared entirely, and that the result was, a quantity of pure water, equal in
weight to the airs employed. The utmost care had been taken to free the airs
made use of, by making them pass through the dry muriat of lime. [These were
the experiments of the French chemists.] The vessel burst in several of his
experiments, because, in the instant of explosion, the vapour of the produced wa-
ter was expanded by the heat extracted from the airs. Much of this heat, to be
sure, ivas expended in giving these the vaporous form, or supplying it with latent
heat. But the vessel was instantaneously heated, shewing that the heat contained
in the two airs more than siifficedfor this purpose. These experiments were
published in the Philosophical Transactions for 1784. [No such observations
were made by Cavendish or published in the Transactions.]

" Such curious experiments, and so interesting a result, could not remain a
secret, had such a thing been intended. But there was no such intention.
Mr. Blagden, Secretary of the Royal Society, went to Paris in June 1783,
and communicated these experiments of Mr. Cavendish to M. Lavoisier, and
his associates, De la Place, Meusnier, Mongez, &c., knowing that they were
much interested in the result, which was so intimately connected with the new
theory which M. Lavoisier was then establishing.

" Accordinglj", M. Lavoisier, who saw the immense consequence of this dis-
covery to his theory, immediately set about repeating the experiments of com-
posing water by the combination of the two airs; and in September 1783,
with the assistance of M. Meusnier, effected the composition in a way that
admitted no doubt."

44.

the errors in this account are such as to exonerate Watt from any su-
spicion of having supplied or revised it.

The fault which, since the subject has been forced into public no-
tice, we are compelled not to leave unobserved in the conduct of the
latter, is the silence with which he passed by the experiments of Ca-
vendish in his letters both to Priestley and De Luc. How fully Priest-
ley's acknowledgment, that Cavendish had made before him the same ex-
periments, was understood by others, appears from the following abs-
tract of the contents of Priestley's paper on the seeming conversion of
water into air, which I have extracted from the Journal Book of the
Royal Society. " These arguments received no small confirmation /wm
an experiment of Mr. Cavendish, tending to prove the reconversion of
air into water, in which pure dephlogisticated air and inflammable air
were decomposed by an electric explosion, and yielded a deposit of wa-
ter equal in weight to the decomposed air." This abstract, which shows
how ill-founded the story is of the discovery of the composition of water
being received with ridicule by the Royal Society, was made by the Se-
cretary of the Society immediately after the reading of Priestley's paper
in June 1 783. The Secretary was Mr. Maty, not Dr. Blagden, who did
not hold the office of Secretary till May 1784, and was not a member of
the Council ; so that he is in no way liable to the suspicion intimated
by Lord Brougham of having shown Watt's letter to Cavendish, nor
to the reproach which M. Arago casts upon him, of not speaking the
whole truth respecting the precise date at which Watt's opinions were
made known in London. The fact is, that there is a good deal of con-
fusion attending this letter of Watt's ; the date with which it is printed
is April 26 ; but that date is corrected in the MSS. in two places to
April 2L Watt says it was received by Priestley in London ; and
yet it is certain that Priestley transmitted it to Sir J. Bankes, with his
own paper, from Birmingham : its date however is of no consequence.
The perusal of the entire letter has satisfied me that the real ground
of Watt's claim to original views on this subject was not the observa-
tion of what he calls " the obvious fact, that inflammable and dephlo-
gisticated air unite with violence, and that water is the only fixed pro-
duct," but the theory which he engrafted on this fact, that the airs are
decomposed, and that their bases, parting with the elementary heat with
which they were combined, enter into a new combination, and so form
water — a theory which Lavoisier had applied generally to the other
pheenomena of combustion six years before.

M. Arago, however, might have found for the subject of his Eloge a
higher ground of scientific praise in less questionable applications of the

theory of latent heat. He has poured the whole force of his eloquent
panegyric on the practical results of the labours of the great engineer,
and the mechanical ingenuity displayed in them ; but he might have
pointed to the early and profound attention which he devoted to this
theory, as the fountain-head of his fame, and shown him in the acade-
mical class room, and the laboratory, of Black, imbibing that spirit,
and advancing those principles of science, which were afterwards em-
bodied in all his works, and gave life to all his inventions ; and he might
thus have taught us, in a manner worthy of his own genius, what it is
more especially, that entitles Watt, rather than Worcester or Papin,
Savery or Newcomen, to be admired as the philosophical parent of
the gigantic and diversified powers of the steam-engine.

APPENDIX.

EXTRACTS FROM THE CAVENDISH MSS. REFERRED TO IN THE
FOREGOING POSTSCRIPT.

EXPERIMENTS ON HEAT.

[When an edition of the works of Cavendish is published, (as I believe is
intended), I hope that these papers on heat will be printed at large with all
the experiments. I have here confined myself to extracting such passages as are
suflScient to substantiate what I have advanced in the Postscript to my Address.
The treatise containing these views, and the general result of the experiments,
was written for the use of some individual, it does not appear whom. The
same is the case with respect to the experiments on arsenic, which follow :
and the date of both these remarkable series of experiments appears to be about
the same, that is to say, certainly not later than 1764 : as with respect to those
on heat the following extract, copied verbatim from the original notes (p. 89)
of the experiments, shews.

" Feb. 5, 1765 : — therm, in room about 35 : heat of liquors in bottles, 34 :
the weight of the bottles with the liquors was known : the liquors were put
into wide-mouthed vessels inclosed in wool, the weight of the glasses being
known; & snow added till therm, sunk to about 19 : the snow seemd not
at all inclinable to melt when taken up, & was put in glass vessel set in mix-
ture of snow & salt water : the heat of snow when made use of was neg-
lected to be tried : the solution of sea- salt sunk to 18^, the spt of wine
to 19, the f. alk. to 22, & the aq. fort, to 19 : the spt of salt was not
tried. After the experiment was finished, the wide-mouthed glasses with

the liquors in them were weighd, & also the bottles which the liquors were
poured out of; by which means the quantity of liquor was known, & also
the weight of the snow ; the result is on the other side the leaf : the small
bottles were not tried."

This entry stands in his note book subsequent to all the entries of experi-
ments on the heat of mixtures of "hot & cold water" — "hot water & quick-
silver" — " hot quicksilver & cold water"-—" hot quicksilver & cold quick-
silver" — "hot water & oil" — "hot quicksilver & cold spts" — "hot spts &
cold spts" — " hot spts & cold quicksilver" — " hot quicksilver & solut. pearl
ashes" — " hot quicksilver & oil vitr." — "silver sand, iron filings, lead shot,
powdered glass, powdered marble, tin shot, powdered charcoal, Newcastle
coal, brimstone, tried in tin bott. in hot water" — " cold spermaceti in warm
water" — " concerning heat & cold produced by hardening & melting of sper-
maceti" — " expts on time of evaporation of boiling water" — " exper. concern-
ing the cooling of water in worm-tub, by blowing air through pipe, & con-
cerning the heating of it by distillation"; — with the following result of the
latter experiments. — " Therefore heat gen. by condens. vapours = 942°." —
MSS. p. 71.

At what date Black and Watt arrived at a similar result I know not. Nor
do I know the precise year in which Black first taught the doctrine of specific
heat. Dr. Thomson says, " That the specific caloric of bodies is difi'erent, was
first pointed out by Dr. Black in his lectures at Glasgow between 1760 &
1765. Dr. Irvine afterwards investigated the subject between 1765 and 1770
(Black's Lectures, i. 504), and Dr. Crawford published a great number of experi-
ments on it in his Treatise on Heat (1779), but Professor Wilcke, who pub-
lished the first set of experiments on the subject (Stockholm Transactions,
1781), introduced the term specific caloric." " I have been informed", he adds,
" by the late Professor Robison, that Wilcke's information was got from a
Swedish gentleman, who attended Dr. Black's lectures, about 1770." It ap-
pears probable, from what I have stated, that this unpublished series of experi-
ments by Cavendish is the first made upon this subject. After these, and im-
mediately preceding those of the date Feb. 1765, is Cavendish's determination
of the number of degrees of "cold gen. by thawing ice or snow," which he
found on an average to be 150°. In the account which Black gives, in his
Lectures, of his determination of the quantity of heat absorbed in the melting
of ice, he says, " these two experiments and the reasoning which accompanies
them were read by me in the Philosophical Club or Society of Professors of
Glasgow in the year 1762." The following is the only notice which Caven-
dish has given of any of his numerous and elaborate experiments on these
subjects. In his "Observations on Mr. Hutchins' experiments for deter-
mining the degree of cold at which quicksilver freezes" (Phil. Trans. 1783.),
he says,

" The cause of the rise of the thermometer when the water begins to
freeze, is the circumstance, now pretty well known to philosophers, that
all, or almost all, bodies, by changing from a fluid to a solid state, or from
the state of an elastic to that of an unelastic fluid, generate heat ; & that
cold is produced by the contrary process. This explains all the circum-

stances of the phenomenon perfectly well." " I formerly found, by adding
snow to warm water, & stirring it about till all was melted, that the water
was as much cooled as it would have been by the addition of the same
quantity of water, rather more than 150° colder than the snow, or in other
words, somewhat more than 150° of cold are generated by the thawing of
snow, & there is great reason to think that just as much heat is produced
by the freezing of water. The cold generated was exactly the same, whe-
ther I used ice or snow. (Note.) I am informed that Dr. Black explains
the above-mentioned phenomena in the same manner, only instead of using
the expression 'heat is generated or produced,' he says, 'latent heat is
evolved or set free'; but as tins expression relates to an hypothesis depending
on the supposition that the heat of bodies is owing to their containing more
or less of a substance called the matter of heat ; 8f as I think Sir Isaac New-
ton's opinion, ' that heat consists in the internal motion of the particles of
bodies,' much the most probable, I chose to use the expression 'heat is gene-
rated.' Mr. Wilcke also, in the Transactions of the Stockholm Academy
of Sciences, explains the phenomena in the same way, & makes use of an
hypothesis nearly similar to that of Dr. Black. Dr. Black, as I have
been informed, makes the cold produced by the thawing of snow 140° ;
Mr. Wilcke, 130°."

He then goes on to mention briefly that he had formerly kept a thermo-
meter in melted tin and lead, &c. And this is all he has said of experiments,
made 19 years before, the notes of which fill 120 pages, 8vo., and the paper of
results and deductions from them, 50 pages, 4to. : the following extracts will
give a general idea of the contents of the latter, and of a fragment which seems
to have been written still earlier.]

FRAGMENT ON HEAT.

Hypothesis.

All bodies, in changing from a solid state to a fluid state, or from a non-
elastic state to the state of an elastic fluid, produce cold, & by the contrary
change they produce heat.

The principal cases in which bodies are changed from a non-elastic to an
elastic state, are the evaporation of liquors, & the separation of fixed air from
alcaline substances.

Before we consider how far this hypothesis agrees with experiment, it may
be proper to premise, that most bodies which have any considerable affinity to
each other, generate heat in mixing. This is well known to be the case in ma-
ny instances : such as mixing oil of vitriol, & the 2 other mineral acids, spirits
of wine, quick lime, & dry pearl ashes, with water, & many other instances,
though in some, such as the solution of salts in water, there seems to be cold
generated, & there seems to be cold produced by the mixture of substances
which have an affinity to each other, as in the solution of salts in water, but
this will be shown to be owing to another cause. I very much question, in-
deed, whether there is any real instance of cold being produced by the mix-
ture of 2 bodies which have no affinity to each other.

4-8

Case 1st.— On the Evaporation of Fluids.

Dr. Cullen has sufficiently proved, in his papers in the Edinburgh Essays,
that cold is produced by the evaporation of all fluids. There is also a circum-
stance daily before our eyes, which proves the same thing, though I do not
know that it has hitherto been taken notice of.

It is well known that water, as soon as it begins to boil, continues exactly
at the same heat till the whole is boiled away, which takes up a very consider-
able time ; I believe I may say several times as much time as it took up to
heat it to the boiling point. No reason however can be assigned why the fire
should not continually communicate as much or nearly as much heat to it after
it begins to boil as it did when it wanted not many degrees of boiling, & yet
during all this time it does not grow at all hotter ; this I think shews that there
is as much heat lost, or in other words, as much cold produced, by the action
of boiling as there is heat communicated to it by the fire.

If no cold was produced by the action of boiling, the water should either
grow hotter & hotter the longer it boils, or else it should be entirely converted
into steam immediately after it begins to boil.

By this means when the water is heated to the boiling point, then as fast as
it receives heat from the fire there is immediately so much of the water turned
into steam as is sufficient to produce as much cold as it receives from the fire,
so that the water is prevented from growing hotter, & besides the water will
not be entirely evaporated till it has received as much heat from the fire as is
produced by turning the whole of the water into steam. The foregoing cir-
cumstance, I think, shews that all animal & vegetable substances, sulphur,
quicksilver, arsenic, & many other metallic & other substances generate
cold by being changed into an elastic fluid or vapour; though it cannot be
shewn by Dr. CuUen's method that they do so, for in distilling any of these
substances it takes up a vast deal of time, after they begin to distil strongly,
before they are all driven over, & there is no reason to think that their heat
increases much after they begin to distil strongly. In general I think there is
great reason to suppose that all the substances whatever, which are capable of
being volatilized by heat, produce cold thereby.

Case 2nd. — I have been informed, that in distilhng water and other liquors,
the water in the worm-tub is heated thereby much more than it would be by
mixing with it a quantity of boiling water equal to that which passes through
the worm.

PAPER ON HEAT.

p. 1. It seems reasonable to suppose that on mixing hot & cold water, the
quantity of heat in the liquors taken together should be the same after the
mixing as before, & that the hot water should communicate as much heat to
the cold water as it lost itself, so that if the expansion of the mercury in the
thermometer is proportional to the increase of heat, the difference of the heat
of the mixture, & of the cold water, as measured by the thermometer, multi-
plied by the weight of the cold water, should be equal to the difference of heats
of the hot water & mixture, multiplied by the weight of the hot water ; or

the excess of the heats of the mixture above that of the cold water should be to
the difference of heats of the hot & cold water, as the weight of the hot wa-
ter to that of the mixture.

P. 4. But before we proceed to compare this experiment with the rule it
was intended to examine, it is necessary to make some corrections.

P. 12. Sect. 2. One would naturally imagine that if cold quicksilver, or any
other substance, is added to hot water, the heat of the mixture would be the
same as if an equal quantity of water of the same degree of heat had been added ;
or in other words, that all bodies heat & cool each other, when mixed together
equally, in proportion to their weights ; the following experiments however will
shew that this is very far from being the case.

P. 26. It should seem therefore to be a constant rule, that when the effects
of any two bodies in cooling one substance are found to bear a certain pro-
portion to each other, that their effects in heating & cooling any other sub-
stance will bear the same proportion to each other.

P. 27. The true explanation of these phenomena seems to be, that it requires
a greater quantity of heat to raise the heat of some bodies a given number of
degrees by the thermometer than it does to raise other bodies the same num-
ber of degrees.

PART II.

P. 33. As far as I can perceive, it seems a constant rule in nature, that
all bodies, in changing from a solid to a fluid state, or from a non-elastic
state to the state of an elastic fluid, generate cold, and by the contrary changes
they generate heat. I shall first consider those cases in which bodies are
changed from a non-elastic to an elastic state, or from an elastic to a non-
elastic state, & afterwards those in which they are changed from a fluid state,
or the contrary.

The reason of this phenomenon seems to be, that it requires a greater quan-
tity of heat to make bodies shew the same heat by the thermometer, when in
a fluid, than in a solid state, & when in an elastic, than in a non-elastic, state.
It is plain that, according to this explanation, all bodies should generate as
much cold in changing from a soUd, as they generate heat by the contrary
change, which as far as I can perceive seems to be the case.

P. 40. I have been informed that Dr. Black has observed that in distilling
water, the water in the worm-tub is heated thereby much more than it would
be by mixing with it a quantity of boiling water equal to that which passes
through the worm. Upon this principle I made some experiments to deter-
mine how much heat is generated by converting water from the state of an
elastic to that of a non-elastic fluid.

P. 43. Experiments to shew that bodies in changing from a solid state to a
fluid state produce cold, & in changing from a fluid to a solid state produce
heat. —

P. 45. I made some experiments to determine the quantity of cold produced
by mixing snow with the following substances, namely, a solution of sea-salt,
pearl ashes, spirit of wine, & aqua fortis. The quantity of cold generated was
not very different from that pioduced by dissolving snow in warm water. I

find also, that cold is generated, by the melting, & heat, by the hardening, of
spermaceti. The cold produced by the melting of spermaceti is sufficient to
cool a quantity of water equal to it in weight above 70 degrees, & nearly the
same degree of heat is produced by the hardening of spermaceti. It was tried
by putting cold spermaceti into hot water, & hot spermaceti into cold water.

P. 46. Some tin & lead were melted separately in a crucible, & a thermo-
meter put into them, & suffered to remain there till they were cold. The
thermometer cooled pretty fast, till the metal began to harden round the edges
of the pot : it then remained perfectly stationary, till it was all congealed : it
then began to sink again. On heating the metal, with the thermometer in it,
as soon as the metal began to melt round the sides, the thermometer became
stationary as near as I could tell at the same point that it did in cooling, and
remained so till it was entirely melted. On putting a thermometer into
melted bismuth, the phenomena were the same, except that the thermometer
did not become stationary till a good deal of the metal was hardened, unless
I took care to keep the thermometer constantly stirring about. It then re-
mained stationary till it was almost hardened. I do not know what this dif-
ference between bismuth & the 2 other metals should be owing to, except to
its not transmitting heat so fast as them. I forbear to use the word conduct-
ing, as I know you have an aversion to it ; but perhaps you will say the word
I use is as bad as that I forbear.

P. 48. All the following mixtures, except the first, differ considerably from
the 3 simple metals in the manner in which they harden in cooling, as they
begin to abate of their fluidity in a heat considerably greater than that in which
they grow hard, whereas in the simple metals I could not perceive any differ-
ence between the heat in which they ceased to be perfectly fluid, & that in
which they hardened.

P. 49. I think it seems likely that the reason why these mixtures begm to
abate of their fluidity in a greater heat than that in which they harden is, that
the metals of which the mixture is composed begin to separate as soon as the
heat is not sufficient to keep the mixture quite fluid. This is confirmed by the
following experiment. The mixture of equal quantities of lead & tin was
melted over again & suffered to remain quiet till cold ; it was then cut in two.
The specific gravity of the upper piece was 8*001, & that of the lower 9'031 ;
so that the upper piece seems to contain much less lead than the lower.

P. 50. Thoughts concerning the above-mentioned phenomena. There are
several of the above-mentioned experiments which at first seemed to me very
difficult to reconcile with Newton's theory of heat ; but on further considera-
tion they seem by no means to be so : but to understand this you must read
the following proposition. —

EXPERIMENTS ON ARSENIC.
[That the paper containing these experiments, like the former, was addressed
to some individual who pursued the same studies, appears from the following
expressions : " As I have spun these papers out to a great length, I will not
repeat the particulars of this experiment, ivhich I showed you before :" and
again, "thus mercury may be revived without the addition of any matter

usually called inflammable, as you fell me you have tried yourself." It has
been twice written over, and is founded on a note-book of experiments, the
date of which is given by the following extract from the 27th page of the
note-book, after the experiment (page 10 of the paper) on the solution of
arsenic in aqua fortis.

" I-IO-O of purified spts of salt, 2 by measure, diluted with ^ the quantity
of water, was put into a piece of flor. flask and heated; 2-8 '0 of arsenical
liquor was poured into it by degrees whilst hot : it efFervd & discharged
fumes as usual, it seemed almost but not quite suflSce. to saturate the acid :
the liquor being evaporated gave crystals of sal Sylvii mixed with nitre. See
p. 53, infra, P. 9- 10.

"Dec. 1764. Into some of this arsenical liquor was dropt some spt salt :
it caused red fumes & turned the liquor rather blue, but, as well as I can
judge, not near so much so as at first."]

Experiments on the solution of Arsenic in f. Alkali.

P. 3. The arsen. is precipitated from these solutions, according to Macquer,
by any acid whatsoever, which as far as I have tried agrees with my own ex-
periments : there is however a remarkable difference between the mineral
acids in this respect ; for if you take any combin, of arsen. & f, alk. in
which thef. alk. bears a considerable proportion to the arsen., & dilute it with
a moderate quantity of water, & then drop into it some oil of vitr, or aqua
fortis, the arsen. is not immediately precip. ; but in a day or two the bottom
and sides of the glass will be found coated with small crystals of arsen. ; part
of the arsen. however remains suspended so strongly as not to be separated
without crystallizing the neutral salt : whereas if you drop spt of salt into
the same solution, or even one diluted with a much larger quantit}' of water,
the arsen. is immediately precip. in white clouds.

P. 4. Arsenic, as was before said, does not begin to efferv. with f. alk. with-
out a greater heat than one can bear one's hand in ; it also seems to require
a much greater heat than that of boiling water to deprive the alcali entirely of
its air. Sulphur also cannot unite to a f. alk. saturated with air without de-
priving it of some of it, which it is not able to do without a greater heat than
that of boiling water ; for which reason there is hardly any impregnating the
milder sorts of fixed alcalies strongly with sulphur merely by boiling together :
with the heat requisite to make liver of sulphur by fusion it is able to deprive
the f. alk. of a great deal of its air, as appears from the frothing or efterv. du-
ring mixing : it however cannot entirely deprive it of its air by that heat, as
the liver of sulphur made by fusion always makes some efferv. with acids,
though not so much as the f. alk. by itself.

Experiments on the neut. arsen. salt.
1st process for neut. arsen. salt.
P. 5. 20'0"0 of nitre was well mixed with the same quantity of arsen., Recom-
mitted to distillation in a retort in reverb., the neck of the retort being luted
into a glass tube whose end was immersed into 20-0-0 of a strong solution of
pearl ashes ; the vapours passed through the f. alk. in the form of red fumes

even in the very beginning of the operation ; as it proceeded, there formed a
white precip. at the bottom of the vessel which contained the f. alk. : the pro-
cess was continued for upwards of an hour after the fumes had almost ceased
to appear, during all which time the heat was kept up much stronger than at
the beginning.

The retort was not red hot, though I should imagine it could not want much
of it. The cake of neutral salt remaining in the retort after the vessels were
taken down weighed about 30-0-0 ; 3-5-0 of loose flowers of arsen. were sub-
limed into the neck of the retort ; little or none was found in that part of the
retort contained within the furnace, & upwards of 4.4 of moist flowers of
arsen. were found in the tube. The arsen. sublimed into the neck of the
retort was found no ways to differ from common arsen.

3- 18 -16 of a solution of dry pearl ashes in equal weight of water were
saturated by 2-8-11 of aquafortis, whose spe. grav. was 1-398 : the loss in
mixing was 10*9. The operation was performed in a flor. flask, & the aqua
fortis was previously diluted with water to avoid too sudden an efferv. : being
evaporated it yielded 2*1 1-19 of dry crystals ; therefore I part of saltpetre con-
tains -936 of aqua fortis, 759 of dry pearl ashes, & -559 of ditto freed from
air.

3'9-4 of arsen. was sublimed into the neck of the retort & tube in the
foregoing distillation; therefore there remains 16-I0-20 of arsenic in the cake
of neutral salt, supposing that no arsen. was carried over in the red fumes, as
in all probability there was not : therefore 1 part of neut. arsen. salt contains
•506 of dry f. alk. saturated with air or -373 of the same alcali deprived of air,
& -551 of arsen. Therefore the proportion of f. alk. and arsen. in the neut.
arsen. salt is 1 part of dry f. alk. saturated with air to 1,082 of arsen.

If the cake of salt remaining after distillation be dissolved in a proper quan-
tity of hot water it readily shoots on cooling into crystals, which do not at all
grow moist in the air, & require about 3^ times their weight of water to
dissolve them.

A solution of these crystals scarcely alters the colour of syrup of violets ; if
anything, they give it a reddish cast ; they turn tournsol paper a brownish-red.
A solution of fixed alcaU being dropt into a solut. of these crystals makes
an effervescence. The quantity of alcaline solution which must be added be-
fore it ceases to effervesce is such, that the dry alcaline salt shall be about f
of the weight of the neutral arsen. salt, or about f of the alcali already con-
tained in the neut. salt.

Chalk or whiting also make a slight efferv. with this solution. Macquer
seems not to have taken notice of this phenom., since he says, it seems in all
respects a perfectly neutral salt ; whereas these experiments plainly show an
excess of acid, unless you suppose that the salt he made differed in this
respect from mine. There is another point in which we differ, relating to the
precipitation made by metallic solutions : he says, that blue vitriol and a solut.
of iron in aqua fortis make a precip. immediately on dropping into a solut. of the
neut. arsen. salt ; but that green vitriol and a solution of copper in aqua fortis
do not make a precip. till after having stood some time : whereas I have always
found that all 4 substances make a precip. the instant they are dropt in.

Experiments on the fixed alcali through which the red fumes were made to pass
in the second process for making neut. arsen. salt.

P. 8. The contents of the vessel after distillation were found to weigh 19*7'0 ;
so that the f. alk. appears, instead of increasing in weight, to have lost about
13 parts by the operation : these contents were put in a bottle, & set in
sand, in order to dissolve the sediment which, as was before said, fell to the
bottom during the process : the bottle broke, but the liquor was saved by the
sand-pot ; it was washed out from the sand by boiling it with fresh parcels of
water; it weighed 36'0*0 : into some of this liquor was dropt oil of vitr.
diluted with about 3 times its weight of water ; it effei-vesced, & discharged
a great quantity of red fumes like those produced in the distillation, & turned
of a blue colour : the same phenom. were produced also by spt of nitre &
spt of salt : distilled vinegar made an efFerv., but did not discharge any fumes ;
nor did the liquor turn blue, but of a pale madeira colour.

It appears from hence, that the nitrous acid is so much altered by this
process as to have a less affinity to f. alk. than the marine acid, though not
so small, I suppose, as distilled vinegar.

Experiments on the solutions of arsenic in the mineral acids — of the arsenical
acid — 8f conjectures concerning its nature.

P. 9. l-O-O of arsen. was put into a flor. flask with 2-0-0 of oil of vitr. With
the assistance of a heat almost enough to make the oil vitr. boil, it dissolved,
but without the least efferv. On cooling, there formed an irregular crystallized
mass at bottom, which weighed about I'lO-O ; some of this crystallized mass
was put into an open cylindrical glass & held over the fire : after some of
the moisture had boiled away it dissolved into a transparent glass : after
standing some time, it grew opake, & attracted the moisture of the air enough
to swell, & burst the glass, but not enough to deliquiate or grow moist. It
appears from hence, that arsen. united to the concentrated acid of vitr. bears
a much greater heat than either of the 2 substances separate : the same thing
is observed of turbeth mineral.

19'4 of arsen. was put into a flor. flask with 2" 17-4 of strong spt of salt &
about 4 part as much water ; it made no efFerv. during heating ; but by the time
the liquor began to boil, it was found to be entirely dissolved : on cooling, a
good deal of white matter stuck to the sides, & some small crystals shot.

If some f. alk. is dropt into this solution, it effervesces, & instantly pre-
cipitates the arsen. in white clouds.

P. 10. The phenom. attending the solution of arsen. in aqua fortis were
found to be very different ; for whereas arsen. dissolves very readily in the
vitr. & marine acids with the assistance of a sufficient heat, but without the
least efFerv. : on the contrary, it dissolved very slowly in the nitrous acid, but
made a great efFerv., & discharged a great quantity of red fumes resembling
those produced in the distillation of neut. arsen. salt, & the solution became
of a bluish-green ; whereas the solut. of arsen. in the vitr. & marine acids did
not in the least incline to that colour : moreover the arsen. by being dissolved
in this acid was found to have undergone the change necessary to enable it to
form the neut. arsen. salt when united to f. alk. : for no arsen. was precip.

from the solut. on saturating it with f. alk., & the saturated solution" yielded
on evaporation crystals of nitre, mixed with other crystals of a different shape,
which proved to be neut. arsen. salt. The success of this exp. induced me
to try whether by dissolving arsen. in aq. fort. & driving off the acid by heat I
could not procure the arsen. which had suffered the above-mentioned change
(or the arsenical acid, if you will allow me to call it by that name) by itself;
the success of which was as follows :

I'O-O of arsen. was put into a flor. flask with 4'15'15 of purified aq. fort.,
another flor. fl. with a hole in the bottom being inverted into the neck of the
1st, & luted to it : with the assistance of heat it efferved & discharged
fumes, which filled both flasks & in part escaped at the hole at top ; part of
the fumes seemed to condense in the upper flask, & run down in the form
of a greenish liquor ; after having been kept over the lamp some time it was
taken off : the arsen. was not near dissolved ; the liquor whilst hot was of a
reddish-yellow, like the fumes which were discharged from it, but when cold
changed to a deep bluish-green, but which went entirely off in 2 or 3 days :
in all probability it proceeded at 1st only from some of the red fumes which
were condensed in the flasks & fell down into the liquor : the remainder of
this ounce of arsen., & also 3 oz. more were afterwards dissolved in it : the
aq. fort, seemed as if it wd have dissolved still more : the solut. was quite
clear and transparent, & did not let fall the least sediment as is usual in
solutions of metallic substances in this acid : the mixture was found to have
lost 16'0 by evap. during this process ; this solut. was put into a retort &
distilled to dryness in a sand heat ; it did not require much heat to do it : at
the end of the operation almost as great a heat was given it as the furnace
would admit of: no arsen. sublimed ; no red fumes nor volatile vapour rose
during the distillation ; some of the distilled liquor was saturated with f.
alk., it seemed to contain little or no arsen., as it made no sensible precip.
with blue vitr. or solution of silver or mercury.

P. 12. The caput mortuum remaining in the retort after the distillation
weighed 4* 13*6, id est, about i part more than arsen., from which it was
made : it attracted the moisture of the air, though but slowly ; it requires very
little water to dissolve it, I beheve scarcely more than -^ its weight ; but it
does not dissolve fast without the assistance of heat.

Into a solut. of this cap. mort. was dropt some f. alk. ; it made a strong
efferv. ; more f. alk. was dropt in till the efferv. was almost, but not quite,
ceased : on evap. it furnished crystals which differed in no respect from the
neut. arsen. salt made in the common manner,

The following experiment was made to see whether this caput mort. con-
tained any of the nitrous acid used in the making of it.

The arsen. acid, as I found by an exper. which will be mentioned after-
wards, when thoroughly saturated with a calcarious earth, forms a substance
which is insoluble in water, & which I beg leave to call calcarious arsenical
salt : some of this caput mortuum therefore was dissolved in a good deal of
water & saturated with whiting : it made a great efferv., & the calc. arsen.
salt fell in flakes to the bottom : after having stood some time, the clear
liquor was strained from the insoluble part : this liquor it is plain must con-

tarn all the nitrous acid (if there was any in the cap. mort.) under the form
of calcarious nitre, but not much of the calc. arsen. salt ; but in order to
free the calc. nitre more effectually from a little of the calc. arsen. salt,
which still remained suspended in the water, the liquor was evap. to dry-
ness, & the solid contents washed with water in order to dissolve all that
was soluble : these washings were found by the addition of a little f. alk.
and evaporation to contain very little, if any, nitrous salt.

It appears from this experiment that this cap. mort. is the pure arsen.
acid, (or the substance, which when united to f. alk. forms the neut. arsen.
salt), without any sensible mixture of the nitrous acid."

It also seems to possess all the properties of an acid (unless perhaps it
should fail in respect to taste, which I have not thought proper to try), since
it effervesces with & neutralizes the fixed & volatile alcalies, & calcarious
earths & magnesia, turns syrup of violets red, & also unites to the earth
of alum, which last the sedative salt & sulphur (substances which possess
some of the properties of acids, but not all) are not able to do.

The excess of the weight of the cap. mort. above that of the arsen. it was
made from must be owing, I suppose, to its retaining some of the water of
the aq. fort, used in making it ; for the following exper. shews that there is
none of the nitrous acid enters into the composition of the arsen. acid, as it
shews a way of making the neut. arsen^ salt without any thing which con-
tains the nitrous acid.

3*0-0 of arsen. was mixed with 3"1'13 of pearl ashes dissolved in water, so
that there was, as well as I can guess, about -rV part more of alk. in pro-
portion to the arsen. than in the neut. arsen. salt : this was boiled till the
arsen. dissolved, & then evap. to dryness : some of this mixture was
pounded fine & calcined over charcoal in a broad shallow earthen pan, care
being taken to keep it frequently stirred : the heat was as great as the matter
could bear without caking together. Some of it was taken out now &
then, & dissolved in water with solut. silver : the colour of the precipitate
formed thereby changed gradually, the more the matter was calcined, from a
pale yellow, which it was of at 1st, to a purplish-red, the same as that
made by neut. arsen. salt : it was then taken off the fire & dissolved in
water : as the f. alk. bore too great a proportion to the arsen. some spt of
salt was dropt into it, till it began to efferv. with f. alk. : soon after the spt
of salt had been added, it grew muddy, & a small quantity of white
sediment fell to the bottom, which seemed to be arsen. ; it was then evap. :
there 1st shot some crystals resembling neut. arsen. salt, & afterwards
some crystals of sal. Sylvii : some of the crystals resembling neut. arsen.
salt were dissolved in water ; the solut. efFerv'd with whiting & f. alk.,
reddend the colour of blue paper, made the same coloured precip. with solut.
silver, & blue vitr., as the neut. arsen. salt ; in a word, I could perceive
no difference between that & the neut. arsen. salt made in the common
manner.

P. 16. I think these experiments shew pretty plainly that the only dif-
ference between plain arsenic & the arsen. acid is that the latter is more
thoroughly deprived of its phlogiston than the former : for all the ways I
know of making arsen. acid or neut. arsen. salt are such as may reasonably

be supposed to deprive the arsen. of its phlogist. : as for example, in making
arsen. acid by solution in aq. fort., the nitrous acid is known to have a great
disposition to lay hold of phlogiston, & there are strong reasons for
thinking that the dissolving of metallic substances in that acid is a very
powerful method of depriving them of it, as I shall take notice of by and by.
It seems likely too, that the nitrous acid may have the same effect in calcining
arsen. & nitre together as in the common way of making neut. arsen. salt ;
but the above-mentioned way of making neut. arsen. salt by calcining the
simple combination of arsen. and f. alk. is a more especial example hereof,
since the natural effect of exposing metallic substances at the same time to
heat & the open air is to deprive them of their phlogiston : the last exper.
too shews that the presence of the open air is almost, if not quite, necessary
to produce this change, since the mixture seems in that exper. to have suffered
but a small part of the change necessary to turn it into neut. arsen. salt,
though exposed both to a greater heat, & for a longer time, than in the
former exper.: perhaps too, if the vessel had been more perfectly closed, it
wd have suffered still less change.

P. 17. The nature of the difference between the arsen. acid & plain
arsen. in some measure favours this opinion, since arsen. acid differs from
plain arsen. much in the same manner as that does from the regulus of
arsenic ; for the regulus of arsen. is indissoluble in water, & has no affinity
to f. alk. ; white arsenic is in some measure dissoluble in water, & has a
very evident affinity to f. alk., thereby manifesting something of an acid
property : the arsen. acid is much more dissoluble in water than white
arsen., has a strong affinity to f. alk., & seems in all respects a real acid.

If these arguments should seem too hypothetical, the following will most
likely be allowed to be satisfactory, namely, that the arsen. acid is easily
reduced into regulus by subliming it with inflammable substances. A small
quantity of arsen. acid was put into an apothecary's vial with about ^ its
weight of linseed oil ; it grew soft, mixed uniformly with the oil, & sublimed
in the form of regulus, with a less heat than sufficient to make the glass red
hot.

The red fumes which issue in the distillation of the neut. arsen. salt & in
the dissolution of arsen. in aq. fort. (& consequently the blue aqua fortis,
which is only these fumes condensed), can be nothing else, I imagine, than
the nitrous acid combined with & volatilized by the phlogiston of the
arsen., though I am quite ignorant why they should differ so much both in
colour & their greater degree of volatility from the same acid impregnated
with phlogiston by dissolving other metallic substances in it. As it appears
from a former experiment that little or no arsen. is elevated in drawing off
the nitrous acid from a solution of arsenic in aq. fort., & as the arsen. acid
made by that means so much exceeds in weight the arsen. it was made from,
it does not seem likely that these fumes contain any arsen.

P. 19. Though what I am going to say has not much relation to the
present subject, I will beg leave to offer a few conjectures concerning the
solution of metals in acids. It is remarkable, that though in general the
nitrous acid has the least affinity to metallic substances of any acid, yet it
dissolves them with the greatest ease of any : this has been with great reason

attributed to the great affinity of the nitrous acid to phlogiston, part of the
acid laying hold of the phlogis. of the metals, & thereby preparing them
for dissolution, whilst the remainder dissolves them. In general the nitrous
acid dissolves metals with great effervescence, produces a considerable heat,
& the vapours produced thereby are of a deeper colour, more pungent, &
more elastic, than those of the simple nitrous acid, or than those produced
by dissolving alcalies and earths in it, which I think can be owing only to
their union with the phlogiston.

As the precipitates from the solution of mercury & the perfect metals in
acids are reducible without the help of inflammable matters, it has been
thought that those metallic substances are not deprived of their phlogiston
by acids ; but yet the vol. sulphureous acid produced in dissolving mercury
in oil of vitr. seems a strong proof that mercury is deprived of its phlogiston
by solution in that acid ; & yet (as you tell me you have tried yourself) the
mercury may be revived from thence without the addition of any matter
usually called inflammable ; I have found too that the same vol. sulph. acid
is produced by dissolving silver in concentrated oil of vitriol : I should
imagine therefore that mercury and the perfect metals were deprived of their
phlogiston by solution in acids, as well as the imperfect ones, but that by
reason of their great affinity to phlogiston they acquired it again from the
matter which must be added to separate the acid from them, since there
seems no reason to think that the purest f. alk., or even lime, is intirely free
from phlogiston. The effervescence & elastic vapours produced during their
solution in aq. fort, or aq. regia, seemingly much of the same nature as those
attending the solution of the imperfect metals in these acids, very well agree
with this hypoth. Whereas it seems likely that if they were not deprived of
their phlogiston thereby, they would dissolve quietly without efferv., as arsen.
does in the vitr. & marine acids. If this hypoth. is true, it may serve to
account for gold not being soluble in any simple acid, but only in aq. regia.
Gold, I imagine, has little or no affinity to the nitrous acid, but only to spt of
salt ; but its affinity to that acid alone is not sufficient to deprive it of its
phlogist. : it therefore requires the united efforts of the nitrous & marine
acids, the nitrous to absorb the phlogist., & the marine to dissolve the
metal. That gold has little or no affinity to the nitrous acid, seems likely,
from what Dr. Lewis says, — that gold when by particular management made
to dissolve in the nitrous acid is precipitated again only by exposure to the
air, & that upon committing a solution of gold in aqua regia to distilla-
tion, the nitrous acid flies off leaving the gold united to the spt of salt.

Miscellaneous Experiments on the Arsen. Acid.

P. 22. 3-4 of arsen. acid was put in a small vial covered & intirely im-
mersed in sand in a crucible, so as to shut off all communication with the
air : it was calcined in this manner for a good while with a heat raised high
enough to make the glass red hot & soft, as appeared from its having received
the impression of the sand : no arsenical fumes were perceived; the arsen.
acid was not melted, & lost but 6 gra. of its weight, which very likely were
only water.

Some more arsen. acid was calcined for a good while in a coffee cup
covered in the same manner, with a heat, I should imagine, sufficient to melt
copper ; no arsenical fumes were perceived on heating, but were very visible
when the crucible was taken out of the furnace ; almost all the arsen. acid was
sublimed : what remained seemed to have been melted, but had no appear-
ance of vitrification.

Some of the arsen. acid was saturated with magnesia : the solution was
evaporated, but it did not seem disposed to crystallize : it presented nearly the
same phenom. with metallic solutions as the neut. arsen. salt.

Some earth of alum was dissolved in the arsen. acid : it dissolved without
efFerv., as it does in other acids ; it did not seem disposed to crystallize ; this
solution made a pretty bright scarlet precip. with solut. silver, whereas the
neut. arsen. salt makes a sort of purphsh-red : the phenom. which it presents
with other metallic soluts are not remarkably different from those made by
the neut. arsen. salt.

The arsen. acid itself makes much the same coloured precipitates with
solut. silver & mercury in nitrous acid, & of tin in spt of salt, as the neut.
arsen. salt : with most other metallic solutions it makes no precip.

Neither the neut. arsen. salt nor any other combination of the arsen. acid
makes any precip. with solut. nickel in aq. regia, and but very little with the
red tincture extracted from zaffer by aq. regia, id est, a solution of regulus
of cobalt : even that little seems owing to the bismuth contained in it.

EXPERIMENTS ON FACTITIOUS AIR.

[The date of these experiments is probably not later than 1767.]

PART IV.

Containing experiments on the air produced from vegetable and animal siibftances

by distillation.

I received the air produced from these substances in inverted bottles of wa-
ter, nearly in the same manner as in the former experiments read to this So-
ciety, by means of the apparatus represented in the annexed drawing.

Exp. 1. 400 grains of raspings of Norway oak, called wainscot by the car-
penters, were distilled in the above-mentioned manner, till no more air would
rise with a heat just sufficient to make the distilling vessel obscurely red hot.
The bottle in which the air was received was then removed, & another put
in its place, & the distillation completed with a pretty strong red heat.
By this means that part of the air which requires a red heat to disengage it
was procured separate from that which rises with a less heat. Each of these
parcels of air were then brought in contact with sope leys in the manner de-
scribed in my experiments on Rathbone-place water, in order to see whether
they contained any fixed airs, & to free them from it if there was any.
The first parcel of air, namely that which rose first in distillation, measured
22100 grains when first made, & was reduced by the sope leys to 12700.

The second parcel measured 34600 grains, & was reduced by the same means
to 30700 grains.

The quantity of common air contained in the distilling apparatus, allowing
for the room occupied by the wood was about 1700 grains ; all of which must
have been forced into the inverted bottle along with the first distilled parcel of
air and would not be absorbed by the sope leys. 1700 is about -j-V of 12700 ;
so that the first distilled air when reduced by the sope leys, contains about
tV of its bulk of common air, or is a mixture of about 13 parts of pure facti-
tious air to 2 of common air. The last distilled parcel must have been in-
tirely free from common air.

All that air which was absorbed by the sope leys may, I think, be fairly sup-
posed to be fixed air. The remaining air of each parcel was inflammable, but
required a much greater quantity of common air to make it explode than the
inflammable air from metals does : for a vial holding near 1200 grains mea-
sure being filled with 1 part of the first distilled air with 24^ of common air,
the moisture caught fire on applying a lighted candle to the mouth of the
vial & went off" with a small pufi^ ; but when the vial was filled with 1 part
of the same air to 2 of common air it would not catch fire. In like manner
a mixture of 1 part of the 2nd distilled air with 3 of common air went off
with a pufi^, but 1 part of the same air with 2i of common air would not.
So that the first distilled air required to be mixed with not less than between
2 and 2f times its bulk of common air, & the 2nd distilled air with be-
tween 2 1 and 3 times its bulk of common air, before it would explode ; whereas
the air from metals, when tried the same way, would explode though mixed
with only f its bulk of common air.

I next tried which of these parcels of air would explode with most force when
mixed with considerably more common air than what was sufficient to en-
able them to catch fire. For this purpose I mixed some of each of these par-
cels of air & also some inflammable air from zinc with 4 times their bulk of
common air, & tried them in the same bottle. The first distilled air went
ofi^ with the least noise. As for the 2 others, I was uncertain which made
most ; but the air from zinc went off" with a sharper sound than the other, &
no light could be seen in the bottle ; whereas in the trial of each of the di-
stilled airs a small light was seen.

The experiment was then repeated with mixtures of each of these airs with
5 times their bulk of common air. The first distilled air took fire, but scarce
any noise. The 2 others went off" as near as I could judge with the same de-
gree of noise, the distilled air with a small light visible in the bottle & a
duller sound, the air from zinc without any light & a sharper sound.

It should seem therefore as if the 2nd distilled air contained about as
much phlogiston as the air from zinc, but that the first did not contain so
much : for when the quantity of common air is considerably more than suffi-
cient to consume the whole of the inflammable air, it seems likely that the
loudness of the explosion should be in proportion to the quantity of phlogiston
contained in the mixture.

In all these experiments the air was measured in a cylindrical glass with
divisions on its sides, in such manner that I think I could not well err more

than 5 grains or a 240th part of the whole mixture. The vial in which the
explosion was made had a glass lube about an inch & •§ long & ^^ of an inch in
bore fitted to its mouth, by way of contracting the orifice.

I also tried the specific gravity of each of these parcels of distilled air in
my usual manner. 10,000 grains of the first distilled air being forced into a
bladder, which held 48,000 grains & had a brass cock fitted to it, the bladder
increased |- of a grain in weight on pressing out the air. So that, supposing
common air to be 800 times lighter than water, this air which was before
said to contain y^j of its bulk of common air should be about Jjrth part lighter
than common air ; & the pure factitious air without any mixture of common
air should be y^A or yjth part hghter than common air, or near 6| times
heavier than inflammable air from metals.

21100 grain measures of the last distilled air being forced into the same
bladder, there was an increase of 12 grains on pressing it out; whence this
air appears to be lighter than common air in the proportion of 1 1 to 6, or
near 4 times heavier than the air from metals.

The caput mortuum or matter remaining in the brass pot after the distilla-
tion was completed, consisting of the wood reduced to charcoal, weighed 134
grains.

On the whole, the 400 grains of wainscot yielded with a heat less than suf-
ficient to make it red hot 9400 gra. measures of fixed air, whose specific gra-
vity was before found to be about If times greater than that of common air,
& 12700 of an inflammable air, which was about Jj parts lighter than com-
mon air, & which required to be mixed with more than 2ce its bulk of com-
mon air to make it explode. With a greater heat than that it yielded 5800
grains of fixed air, & 30700 of an inflammable air, which required to be mixed
with above 2i times its bulk of common air to make it explode, & whose den-
sity was -^ of that of common air. The weight of all this air together is 64
grains, id est, ^-^^ of the weight of the wood it was produced from, or near i
of the loss of weight which it suiFered in distillation. It must however be ob-
served that there was most likely more fixed air discharged than is here set
down ; as in all probability some of it must have been absorbed by the water.

As this inflammable distilled air is much heavier than that from metals, &
requires to be mixed with a much greater proportion of common air to make
it explode, I at first imagined it might consist of an inflammable air exactly
of the same kind as that from metals, mixed with a good deal of air, heavier
than it, & which had a power of extinguishing flame like fixed air ; as I hinted
before with regard to the air produced from meat by putrefaction : but on con-
sideration, I fancy this must really be of a different kind from that of metals ;
for if it had been only a compound of that air with some of a different kind,
then a mixture of that compound with common air must necessarily, I think,
have exploded with less noise than a mixture of pure inflammable air with the
same proportion of common air; as it contains less inflammable matter than
the latter mixture, & that compounded with a substance which should rather
diminish than increase the explosion ; whereas the last distilled air was
found to make as great an explosion as the air from metals, when both were
mixed with 4 times their bulk of common air.

Exp. 2. In another trial made in the same manner, except that the whole
of the distilled air was received together, without changing the bottle, the like
quantity of wainscot yielded 19200 grain measures of fixed & 42700 of in-
flammable air. The inflammable air requires to be mixed with more than
2ce its bulk of common air to make it explode, & its density was less than
that of common air in the proportion of 1"52 to 1. The weight of the whole
of this air is 71 grains, id est, near -^jy of the wainscot it was produced from.
This experiment is exactly consistent with the former, except that the quan-
tity of fixed air was greater, as might be expected, since the distillation was
performed in much less time, & consequently much less fixed air could be ab-
sorbed by the water.

Exp. 3. I made another experiment with the same quantity of wainscot, the
distilling pot being this time placed in oil, that I might see what would be the na-
ture of the air which would rise with no greater heat than that of boiling oil.
The oil caught fire, which prevented me from completing the experiment ; I
however got 1 1500 grain measures of air, 5400 of which were fixed air, the re-
maining 6100 were inflammable, requiring somewhat more than 2ce their bulk
of common air to make them explode. Their density, allowing for the common
air in the distilling vessel, was about j^g- part greater than that of common air.

Exp. 4. I also examined the air produced from tartar by distillation, though
not in so careful a manner as the wainscot. It yielded more fixed & less in-
flammable air than wainscot ; 400 grains of it yielded 46600 grains of fixed
air & 23500 of inflammable air. The inflammable air required to be mixed
with more than 4 times its bulk of common air to make it explode, & was
about Yi part heavier than common air.

Exp. 5. 900 grains of hartshorn shavings were distilled exactly in the same
manner as the wainscot in the first experiment, except that the heat was raised
to a rather greater degree before the bottle was changed. The first distilled
parcel of air measured 33600 grains, & was reduced by sope leys to 20400.
The common air left in the distilling vessel was 1630 grains ; so that this air
when reduced by the sope leys contained 3^ of its bulk of common air. The
last distilled parcel measured 9400 grains, & was reduced by sope leys to
8900.

Each of these parcels of air, when thus reduced, was found to be inflam-
mable. The first distilled air, tried in the same bottle as was used for similar
experiments on the air from wainscot, caught fire on applying a lighted candle
when mixed with 5 times its bulk of common air, but would not when mixed
with only 4 times its bulk. The 2nd parcel caught fire when mixed with 2§
times its bulk of common air, but would not with 2ce its bulk. I then com-
pared the loudness of the explosion made by each of these parcels of air & of
some air from zinc, when mixed with 6 times their bulk of common air ; I could
perceive very little difi"erence between the 2 parcels of distilled air, but both of
them seemed to make rather more noise than the air from zinc. The same
difference in the manner of explosion between the distilled air and air from
zinc might be observed with these as with that from wainscot ; namely, that
the distilled airs went off with the duller sound, & exhibited a light in the
bottle, which was not visible with the air from zinc.

18240 grain measures of the first distilled air being forced into a bladder
holding about 21600, there was an increase of weight of 51 grains on pressing
out the air ; so that, allowing for the common air mixed with it, the pure fac-
titious air is lighter than water in the proportion of 13/ to 100.

8160 grain measures of the 2nd distilled air being forced into a bladder
holding near 14000, it increased 4^ grains on pressing out the air, whence it
appears to be lighter than common air in the proportion of 171 to 100.

The caput mortuum, consisting of the hartshorn burnt to a coal, weighed
623 grains. The weight of all the air discharged appears, from what has been
said, to be 5 1 grains, id est, -j^ part of the weight of the hartshorn, or about -^
of the loss of weight which it suffered in distillation.

We have examined, therefore, 3 substances of very different natures, namely,
the first a simple wood, the 2nd a vegetable substance of a saline nature, &
the 3rd an animal substance of the nature of bones. Each of them agreed in
furnishing some fixed & some inflammable air, but the proportions of these
airs were considerably different, & the nature of the inflammable air was not
quite the same in each, but yet hardly differing more than that produced from
the same substance at different periods of the distillation ; so that there
should seem to be a considerable resemblance between the air produced by
distillation from all animal & vegetable substances.

In the first & 2nd experiments we have an examination of all the air which
can be procured from wainscot by distillation in close vessels ; but this is by
no means all the air which it contains ; for the caput mortuum, which, as was
before said, consists of the wood burnt to charcoal, seems to contain a verj'^ re-
markable quantity of fixed air.

The alcali produced by deflagrating nitre with charcoal is well known to ef-
fervesce with acids, & consequently to contain fixed air ; which air, I think,
can proceed only from the charcoal ; for when nitre is alcalized by metals in
their metallic form, which contain no fixed air, the alcali makes no efferves-
cence with acids ; as I know by experience : & I think it seems very unlikely
that the nitre should furnish fixed air when deflagrated by charcoal, & not
produce any when deflagrated by metals. This induced me to make the fol-
lowing experiments.

Exp. 6. 150 grains of the caput mortuum remaining after the distillation
of wainscot in the first & 2nd experiments, well dried, were ground with 5
times their weight of nitre and about 130 grains of water, & when the whole
was thought to be perfectly mixed, it was deflagrated by little & little in an iron
ladle. The intention of the water was to make the matter deflagrate with
less violence ; whereby there was less danger of any fixed air being dissipated
by the heat. The deflagrated matter was put into water to dissolve the alcali.
The insoluble matter, consisting partly of the ashes of the caput mortuum
& partly of some of the caput mortuum which had escaped the fire, weighed,
when well dried, 38 grains ; so that the loss of weight which the caput mor-
tuum suffered in deflagration was 112 grains. In order to find the quantity
of fixed air in the alcaline solution, 4 of it was saturated with the vitriolic
acid, & the loss of weight which it suffered in effervescence observed with the
same precautions as were used for finding the quantity of fixed air in pearl

ashes in the 2nd part of these experiments : it appeared to contain 62 grains.
As this experiment makes the quantity of fixed air produced from the caput
mortuum appear to be greater than the loss of weight which it suffered in de-
flagration, which is impossible, I took another method to find the quantity in
the remaining i of the alcaline solution ; namely, I mixed it with a sufficient
quantity of lime water, whereby all the fixed air therein was transferd into
the lime, which was thereby precipitated.

I then found the quantity of fixed air in this precipitate ; it appeared to be
59 grains, which is only 3 grains less than it appeard to be the other way. By
a mean of these experiments, the quantity of fixed air separated from the 150
grains of caput mortuum should be 121 grains, which is 9 grains more than
the loss of weight which it suffered in deflagration.

By a like experiment made with some more caput mortuum of the same
kind the quantity of fixed air seemd still greater.

As it is impossible that the quantity of fixed air separated from the caput
mortuum should exceed the loss of weight which it suffers in deflagration, I
must either be mistaken in supposing that all the fixed air in the alcali pro-
ceeded from the caput mortuum, & not from the nitre ; or else some moisture
must have flown off along with the fixed air in saturating the alcali with the
acid : which would make the quantity of fixed air therein appear greater than
it really is. This last supposition seems much the most probable.

PAPER ON MEPHITIC AIRS.

[On this Paper Cavendish has written, " communicated to Dr. Priestley."
In the account given by Priestley of his Experiments and Observations made
in and before the year 1772 (Sect. 6. Ed. 1774. p. 109.), he says, " Ever
since I first read Dr. Hales's most excellent Statistical Essays, I was particu-
larly struck with that experiment of his, in which common air and air gene-
rated from the Walton pyrites by spirit of nitre, made a turbid red mixture,
and in which part of the common air was absorbed ; but I never expected to
have the satisfaction of seeing this remarkable appearance, supposing it to be
peculiar to that particular. Happening to mention this subject to Mr.
Cavendish, when I was in London in the spring of the year 1772, he said
that he did not imagine but that other kinds of pyrites, or the metals, might
answer as well, and that probably the red appearance of the mixture de-
pended upon the spirit of nitre only : this encouraged me to attend to the
subject." We have already seen the notice which Cavendish had taken of
nitrous gas and nitrous acid as early as 17G4. Section 9, p- 143, begins
thus : — " Being very much struck with the result of an experiment of the
Hon. Mr. Cavendish, related Phil. Trans, vol. Ivi. by which, though he
says he was not able to get any inflammable air from copper by means of
spirit of salt, he got a much more remarkable kind of air, one that lost its
elasticity by coming into contact with water, I was exceedingly d?sirous
of making myself acquainted with it." In Section 7 of the same account
of his Experiments in and before 1772 (.Ibid. p. 129), Priestley adds, "Air
infected with the fumes of burning charcoal is well known to be noxi-

ous, and the Hon. Mr. Cavendish favoured me w^ith an account of some ex-
periments of his, in which a quantity of common air was reduced from 180
to 162 ounce measures, by passing through a red hot iron tube filled with the
dust of charcoal. This diminution he ascribed to such a destruction of com-
mon air as Dr. Hales imagined to be the consequence of burning. Mr.
Cavendish also observed that there had been a generation of fixed air in this
process, but that it was absorbed by soap leys. This experiment I also
repeated, with a small variation of circumstances, and with the same result."
The following paper, containing the first clear description of nitrogen as a
distinct gas, is the communication thus defectively described. Cavendish,
in fact, was the first to point out, as distinct /achVioi^s airs, besides hydrogen,
the carburetted gases, nitrous gas, muriatic acid gas, and nitrogen] : —

Paper communicated to Dr. Priestley.

The receiver used in the 9th experiment of my 2nd paper on factitious
air was a bolthead, from which I had cut off the greatest part of the neck,
& thereby consisted of a globular body about 9 inches in diameter, with a
neck about 2 or 3 inches in diameter & about 2 inches long.

As the fixed air was let into the receiver first, & the common air after-
wards, I think they could hardly fail of being well mixed together by the
commotion made by letting in the common air. However, as Dr. Priestley
thinks they were not, & that it was owing to that that the candle went out
so soon, I made an experiment to see whether they were well mixed or not ;
this I did by seeing whether the candle would burn as long in a mixture con-
taining x'xV of fixed air, when held near the bottom of the receiver, as when
held near the top. For if the air was not perfectly mixed, the fixed air, as
being the heaviest, would have kept chiefly at the bottom of the receiver, &
consequently the candle would have burnt longer at the top than at the bottom
of it. The event was as follows : — When the candle was held at the bottom
of the receiver it burnt 21", when held near the top it burnt in three different
trials 17", 26", & 19". The same candle burnt, in the same receiver filled
with common air only, when held near the bottom, 82" & 69"; & when
held near the top it burnt 79" and 66" ; so that the 2 sorts of air seem to
have been perfectly mixed. The experiment was tried just in the same
manner & with the same receiver as that related in the Transactions ; &
the candle, in those trials where I have said it was held near the bottom of
the receiver, was held in the same situation as in that experiment. N.B. It
was by mistake that I made only 1 trial with the candle near the bottom &
3 with it near the top, as I intended to make two trials in each manner.

There is no experiment related in that letter of Dr. Priestley's which you
read to me, that shows that mephitic air will mix with common air in time,
of itself, without any shaking, as he says that phials of common air, held in
vessels of mephitic air, became mephitic, which could only be owing to some
of the mephitic air mixing with the common air therein, which, according to
my experiment, wd render it unfit for candles to burn in, & in all pro-
bability wd render it unfit for breathing, which is what I suppose he means
by becoming mephitic. I am not certain what it is which Dr. P. means
by mephitic air, though from some circumstances I guess that what he

speaks of in this letter was that to which Dr. Black has given the name of
fixed air. The natural meaning of mephitic air is any air which suffocates
animals (& this is what Dr. Priestley seems to mean by the word), but in
all probability there are many kinds of air which possess this property. I
am sure there are 2, namely, fixed air, & common air in which candles
have burnt, or which has passed thro' the fire. Air which has passed
thro' a charcoal fire contains a great deal of fixed air, which is generated
from the charcoal, but it consists principally of common air, which has suf-
fered a change in its nature from the fire. As I formerly made an experi-
ment on this subject, which seems to contain some new circumstances, I will
here set it down.

I transferd some common air out of one receiver through burning char-
coal into a 2nd receiver by means of a bent pipe, the middle of which was
filled with powdered charcoal & heated red hot, both receivers being in-
verted into vessels of water, & the 2nd receiver being full of water, so that no
air could get into it but what came out of the first receiver & passed through the
charcoal. The quant, air driven out of the first receiver was 180 oz. measures,
that driven into the 2nd receiver was 190 oz. measures. In order to see whether
any of this was fixed air, some sope leys was mixed with the water in the bason,
into which the mouth of this 2nd receiver was immersed ; it was thereby re-
duced to 168 oz., so that 24 oz. meas. were absorbed by the sope leys, all of
which we may conclude to be fixed air produced from the charcoal ; therefore
14 oz. of common air were absorbed by the fumes of the burning charcoal,
agreeable to what Dr. Hales and others have observed, that all burning
bodies absorb air. The 166 oz. of air remaining were passed back again in
the same manner as before, through fresh burning charcoal into another
receiver; it then measured 16/ oz., & was reduced by sope leys to 162 oz.,
so that this time only 5 oz. of fixed air were gen. from the charcoal, & only
4 oz. of common air absorbed. The reason of this is, that since the air was
rendered almost unfit for making bodies burn by passing once through the
charcoal, not much charcoal could be consumed by it the 2nd time ; for char-
coal will not burn without the assistance of fresh air, & consequently not
much fixed air could be generated, nor much common air absorbed. The
specific gravity of this air was found to diff"er very httle from that of common
air; of the two it seemed rather lighter. It extinguished flame, & ren-
dered common air unfit for making bodies burn, in the same manner as fixed air,
but in a less degree, as a candle which burnt about 80" in pure common air,
& which went out immediately in common air mixed ^vith /s- of fixed
air, burnt about 26" in common air mixed with the same portion of this
burnt air.

LETTER OF CAVENDISH TO MONGEZ.

A Londres, ce 22 Fevrier, 1785.

En lisant. Monsieur, la traduction de mon memoire sur I'air public dans le

Journal de Physique, je fus frappe de le voir datte de Janvier 83, comme si la

lecture en eut ete faite alors devant la Societe Royale. J'eus recours aux

exemplaires detaches imprimes pour I'usage de mes amis sur I'un desquels

appal-emment avoit ete faite votre traduction ; je trouvai a raon grand etonne*
ment, que rimprimeur avoit fait cette meme faute dans toutes les copies,
malgre que roriginal public dans les Transactions Philosophiques avoit ete
datte, comme il devoit I'etre, de Janvier 84. Jevous serai tr^s oblige. Mon-
sieur, de vouloir bien faire mention de cette meprise dans le caliier prochain de
votre Journal.

Je suis mortifie d'etre dans le cas d'ajouter qu'il s'en faut de beaucoup que la
traduction soit exacte ; on a manque le sens en plusieurs endroits.
J'ai I'honneur d'etre avec des sentimens distingues.
Monsieur,
Votre tres humble et tres obeiss' serviteur.
A Monsieur T. A. Mongez, le Jeune, &c. &c. &c.,
Au Bureau du Journal de Physique a Paris.

EXTRACT FROM A LETTER OF CAVENDISH TO DR. BLAGDEN.

I have been reading La V. preface. It has only served the more to con-
vince me of the impropriety of systematic names in chemistry, & the great
mischief which will follow from his scheme, if it should come into use. He
says, very justly, that the only way to avoid false opinions is to suppress
reasoning as much as possible, unless of the most simple kind, & reduce it
perpetually to the test of experiment ; & can anything tend more to rivet a
theory in the minds of learners than to found all the names which they are
to use upon that theory ?

But the great inconvenience, is the confusion which will arise from the dif-
ferent hypotheses entertained by different people, & the different notions
which must be expected to arise from the improvements continually making.
If the giving systematic names becomes the fashion, it must be expected that
other chemists, who differ from these in theory, will give other names agree-
ing with their particular theories, so that we shall have as many different sets
of names as there are theories : in order to understand the meaning of the
names a person employs, it will be necessary first to inform yourself what
theories he adopts. An equal inconvenience, too, will arise from the neces-
sity of altering the terms as often as new experiments point out inaccuracies
in our notions, or give us further knowledge of the composition of bodies.
But to show the ill consequence of what they are about, let them only con-
sider what would be the present confusion, if it had formerly been the fashion
to give systematic names, & that those names had been continually altered
as people's opinions altered. The great inconvenience is the fashion which
so much prevails among philosophers, of giving new names whenever they
think the old ones improper, as they call it. If a name is in use, & its
meaning well ascertained, there is no inconvenience arises from its conveying
an improper idea of the nature of the thing ; & the attempting to alter it
serves only to make it more difficult to understand people's meaning.

With regard to distinguishing the- neutral salts of less common use by
names expressive of the substances they are composed of, the case is different ;
for their number is so great, that it would be endless to attempt to distinguish

them otherwise ; but as to those in common use, or which are found natu-
rally existing, I think it would be better retaining the old names. And with
regard to salts whose properties alter according to the manner of preparing
them, such as corrosive sublimate, calomel, &c. &c., I should in particular
think it very wrong to attempt to give them names expressive of their com-
position.

As I think this attempt a very mischievous one, it has provoked me to go
out of my usual way & give you a long sermon. I do not imagine, indeed,
that their nomenclature will ever come into use ; but I am much afraid it will
do mischief, by setting people's minds afloat, & increasing the present rage
of name-making.

EXPERIMENTS ON AIR.

[These experiments occupy about 100 sheets, of 4 pages each, of which some
are blank, in whole or in part : they are numbered and indexed, as well as
written, by Cavendish's hand : their arrangement is generally in the order of
time, but on making a second experiment to the same effect as one made be-
fore, he has sometimes entered it out of that order, on a blank page, after the
first : thus at page 128 an experiment of Nov. 1782 is inserted among those
made in 1781, of which it was a repetition. The following lithographic ex-
tracts contain all his experiments relating directly to the composition of water,
& involve all the reasonings of his paper in the Transactions on this subject :
the remainder relate chiefly to the analysis of air, and of the gases proceed-
ing from charcoal, and from its combustion with nitre. Among those which
he did not think it worth while to relate, is one which shows the unsettled
state of opinion respecting the general properties of gases,]

Note-book, p. 80. — " It was tried whether the visinertieB ofphlogisticated
was the same in proportion to its weight as that of common air, by finding
the time in which a given quantity passed through a given hole, when urged
by a given pressure, by means of the following apparatus : —

" A is a tin vessel, eight and a
half inches in diameter and ten
deep, with a small hole in the
diaphragm, a. This vessel is
suspended over a vessel of water
by the rod B, turning on a cen-
tre near the middle point, and
partly balanced by a weight at
the other end, and suffered to
descend as the air runs through the hole. The time in which it descended
a given space (about seven inches and a half), was found by observing the
time in which the knob b moved from one mark to another. The force with
which the vessel was pressed down*was about ten and a half ounces, the rest
of the weight of the tin vessel being taken off by the counterpoise. Tlie way
by which it was filled with air was, by holding it under water till all the air

was run out, then stopping the pipe with the thumb, raising up the vessel
till the bottom was near the surface, and pouring in the air. The event was
as follows, October 28, 1780 :

With common air it was .... 2" 15 running out.

A second time 2'12i

With air phlog. by liv. sulpht. 27

With com. air 2*9

" The spe. gra. of this air was tried by forcing 13895 of it into a bladder,
when it increased -,2^ of gra., by forcing out the air : therefore spe. gra.
= ,V l^ss than that of com. air : its test

With N. air was 186

Com. air 197

Two measures of air 201-8."

EXPERIMENTS ON AIR.

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REPORTS

THE STATE OF SCIENCE.

REPORTS

THE STATE OF SCIENCE.

Report on the present state of our knowledge of Refractive
Indices for the Standard Rays of the Solar Spectrum in dif-
ferent media. Presented to the British Association for the
Advancement of Science. By the Rev. Baden Powell,
M.A., F.R.S., F.G.S., F.R.Ast. S., Savilian Professor of
Geometry, Oxford.

[With two Plates.]

AN submitting to the British Association a Report on this sub-
ject, on the present occasion, after having already, from time to
time, made various statements relative to such results, both to
the Association and in published papers, — it may be necessary
to explain, that those former statements embraced only detached
portions of the subject, and in many instances contained only
first, imperfect, and approximate results, which I was neverthe-
less anxious to bring forward at the time, in order to afford
some means of attempting comparisons with theory. These
results have been since rendered more accurate by further repe-
titions, and some points which seemed doubtful, no\v cleared
up : though I have still to regret that it has not been in my
power, as yet, materially to extend the range of media examined.
To state, however, the entire series of such results as I can now
with any confidence offer, and to collect in one view all the
other determinations of the kind as yet known to have been ob-
tained, is the object of the present Report.

The historical memoranda of these researches may be briefly
stated by way of introduction.

Fraunhofer was beyond question the first who used the dark
lines as points of measurement for the deviations of definite
primary rays, in seven kinds of glass, and three liquids. His
original memoir appears in the Munich Transactions [Benk-

voL. VIII. 1839. B

2 NINTH REPORT — 1839.

schriften der Academie der Wissenschaften zu Miinchen fur die
Jahre 1814, 1815, band v.). This M^as translated into French in
Schumacher's Asti^onomischen Ahhandlungen, Zweites Heft,
Altona 1823 ; and from this last an English translation was
made in the Edinburgh Philosophical Journal, Nos. 18 and
19, Oct. 1823.

M. Rudberg (in Poggendorff's Annalen, band xiv. § 45,
and band xvii.) gave similar series of results for the ordinary
and extraordinary refractions, and those along the axes of elas-
ticity of several crystals.

The importance of extending such observations vi^as urged by
Sir J. F. W. Herschel, in his Treatise on Light (§ llf/. and
1121.), in 1827. The same recommendation was repeated by Sir
D. Brewster, in his Report on Physical Optics to the British As-
sociation in 1833 (Second Report, p. 319); and with peculiar
force, as coming from a philosopher who had done so much for
the determination of refractive powers, and almost everything
for the dispersive powers, of a vast range of substances.

This led to the formal recommendation of such researches
by the Association (Third Report, p. 473) ; and a grant was
placed at my disposal, for the prosecution of this object, at the
Dublin Meeting, 1835. I used every endeavour to carry on the
observations ; and though I found the difficulties in practice
greater than I had anticipated, I was able to present at the
Bristol Meeting in 1836, and circulated in print, a series of first
approximate determinations of indices for various media, which
was afterwards embodied in the memoirs of the Oxford
Ashmolean Society. Through the same body I published
"Additional Observations," &c. in 1838, containing repetitions
of some important measurements, with a view, not only to in-
creased accuracy, but to the settlement of some points which
seemed doubtful. Some discussion which took place on these
points at the Newcastle Meeting, 1838, led to a further exami-
nation ; and during the present year I repeated the most im-
portant determinations, together with some additional investi-
gations, which were printed by the Ashmolean Society under
title of " A Second Supplement to Observations," &c., 1839.
These are referred to in the following report under the designa-
tion of First, Second, and Third Series, respectively.

The object of this Report is to bring together all the data we
at present possess of this kind, in a uniform tabular arrange-
ment, which will comprise, —

1st. Fraunhofer's Indices.

2nd. Those of M. Rudberg.

3rd. Those obtained by myself, collected from my several

REPORT ON REFRACTIONS OF SOLAR SPECTRUM. 3

papers^ taking the mean where the different sets were compara-
ble ; and in other cases adopting those which appeared to me
most to be relied on.

My observations were made with an apparatus, the essential
parts of which are a graduated circle, having the prism at its
centre, and a small achromatic telescope with cross wires, and
a power of 10 nearlj^, directed to the prism, and moveable on
an arm about the centre, along with the index. The diameter is
10 inches ; the limb is divided on silver to 10', and by two oppo-
site verniers with lenses to 10". It was originally made and di-
vided by Allan, but fitted up for this special purpose, under my
directions, by Mr. Sirnms. The whole will be directly under-
stood by inspection of the annexed plate. (See Plate I.)

The slit, which is the origin of light, is about g^jth of an inch
broad, formed by the edges of two brass plates made by Mr.
Simms, and inserted in a screen, outside of which is the usual
apparatus for throwing the sun's rays into any convenient di-
rection ; the prism is placed at about 12 feet distance.

The absolute deviation of each ray is thus observed directly
from the zero point, or that which is shown on directing the te-
lescope to the slit. The adjustment for parallelism in the edge
of the prism with the slit is easily made, and the position of
least deviation found accurately by the cross wires and fixed
lines.

From the observed deviations, the indices are deduced by the
well-known formula {B being the minimum deviation, t the
prism-angle, and fi the index,)

log. fj, = log. sin. ~ log. sin. y.

For liquids, hollow prisms or troughs of truly parallel plate-glass
were employed, the angle of each being determined by a me-
thod described in my second paper; a thermometer was inserted,
and the temperature of the medium always noted.

In the course of my observations some doubt had arisen as to
the exact identi/icafion of certain of the standard rays, according
to Fraunhofer's designation of them, owing to the very defective
representations given of them in various optical treatises, which
fail to convey the peculiar characteristics which mark the differ-
ent bands.

Among the larger maps of the spectrum, that in the Edin-
burgh Encyclopaedia (art. Optics, plate 433, fig. 16.) is profess-
edly copied from Fraunhofer's, which is given in Schumacher's
Journal, before referred to, (tab.ii. fig. 6.) ; and this, taken from
that in the Munich Transactions (tab. ii. fig. 5.). This last
b2

4 NINTH REPORT — 1839.

appears to me superior in delicacy of representation, conveying
by shading (which is by no meaiis so good in Schumacher's
print) an idea of the relative intensity of the different parts of
the spectrum. Both preserve admirably the varied characters
of the several groups of lines, and present a faithful picture of
the actual object. All this, however, is almost entirely lost in
the plate in the Edinburgh Encyclopaedia, the execution of
which is coarse, and the characters of the different bands ill
preserved, especially at G ; while two small groups of lines be-
tween and below the bands at H, are made so conspicuous as to
be mistaken for them. In the plate in the Edinburgh Philoso-
phical Journal (No. 18.), H is distinctly marked at the point
midway between the two bands, instead of being opposite the
lower.

In the plates in the Munich Transactions, and in Schu-
macher's Joui-nal, the appearance of the numerous lines about
G is beautifully given -, and I have closely compared these re-
presentations with the actual object, both as seen in the small
telescope of my apparatus, and also in one with a power of 20.
With this power all the smaller lines are seen as in Fraunhofer's
plate, but it is insufficient to resolve the two broad bands. In
that plate, however, they are represented as formed of masses of
very fine lines close together; and in the less refrangible group,
as nearly as possible at its centre, there is one line a little
stronger than the rest, opposite to which G is marked.

Thus, the middle of the lower band, in my observations, ap-
pears correctly taken for the exact position of G. As some
guide to the appearance and position of the lines, I have an-
nexed a map laid down from my own observations, and giving
their general character as exhibited in the small telescope of my
apparatus (see Plate II.).

With regard to the accuracy of the observations, and the de-
gree of accordance between one set and another, it should be
borne in mind, that the liquid prism is necessarily exposed to
the heating power of the sun's rays during the whole time of
observation. Hence, the refractive power will be liable to con-
tinual small changes ; for which evil no remedy seems applica-
ble, but that which may be supplied in multiplying observations,
from which, it may be presumed, the resulting mean values will
furnish determinations on which increasing reliance may be
placed. In general, the observations at higher temperatures
are less to be depended on.

No comparison can be made between the refractive powers of
different media, until some means can be found of reducing them
to a common temperature. I find a proportional diminution

REPORT ON REFRACTIONS OF SOLAR SPECTRUM. 5

of the indices, for an increase of temperature will not hold good
except within very confined limits.

In many media the violet and blue rays are absorbed ; and in
others the lines are very faint, or invisible : in some such cases,
however, their position might be estimated nearly by means of
coloured glasses. Some results of this kind I have stated, di-
stinguishing them as only rough approximations, in cases where,
from the nature of the substance, we can hardly hope to obtain
more accurate results. Among those media of this class which
I have recently examined, is the liquid ammonia ; the volatile
nature of the substance being such as to occasion so great a
want of homogeneity that no lines are visible, and the measures
are only rough estimations.

In some cases, and those among the most interesting, not
even such approximate measures appear attainable. This was
especially the case in that highly important instance, the chro-
mate of lead. A good specimen of this crystal was kindly pre-
sented to me by H. J. Brooke, Esq., F.R.S., which was (not
without considerable difficulty) cut into a prism of small angle
by Mr. Dollond. But the appearance of the spectrum was
altogether confused, and the blue end wholly absorbed, so that
no measures could be obtained.

In some of my first series of observations, no distinct mea-
sures were taken for the two bands at H, but the middle point
between them was taken. Such results are rejected in the pre-
sent report. But in the low-dispersive cases, the difference is
so minute, that I have thought it quite sufficient to introduce a
small proportional correction, to reduce the index to the exact
position of H.

Some observations given from the first series, for certain
chemical solutions of very low dispersive power, are of little
value, since the differences of temperatvu-e render comparison
impracticable, though the whole subject of the indices of
chemical compounds, compared with those of their elements, is
one well deserving more full investigation.

Results for a few other media are added from observations
now first published ', among which will be found rock-salt, so
interesting from its relations to heat.

I had entertained hopes of being able before this time to
obtain results for a much more extended range of substances,
especially those of the more highly dispersive class. But there
are many difficulties in procuring specimens in a state suscepti-
ble of this mode of prismatic examination ; there are also many
substances, and among them the most important, to which it is
to be feared such examination cannot be applied.

6 NINTH REPORT — 1839.

My present Report will therefore be found to embrace only a
small number of media of the more important class, but in
which, after repeated examination, I think the results may be
relied on.

Table I.
Indices determined by Fraunhofer.

I.— Flint-glass, No. 13. Specific gravity, 3723.
Temp. 15°Reaum. = 18°'75 Centig.

1-627749

1-629681

1-635036

1-642024

1-648260

1-660285

1-671062

II. — Ditto, No. 23. Sp. gr. 3'724. Mean of observations
with two different refringent angles.

1-626580

1-628460

1-6336665

1-640519

1-646768

1-6588485

1-669683

III.-Ditto, No. 30. Sp. gr. 3*695.

1-623570

1-625477

1-630585

1-637356

1-643466

1-655406

1-666072

IV.— Ditto, No. 3. Sp.gr. 3-512.

1-602042

1-603800

1-608494

1-614532

1-620042

1-630772

1-640373

V. — Crown-glass. M. Sp. gr. 2*756.

1-554774

1-555933

1-559075

1-563150

1-566741

1-573535

1-579470

VI.— Ditto, No. 9. Sp.gr. 2*535. Temp. 14° R. = 17°*5 C.

1-525832

1-526849

1-529587

1-533005

1-536052

1-541657

1-546566

VII.— Ditto, No. 30. Sp. gr. 2*535.

1-524312

1-525299

1-527982

1-531372

1-534337 1-539908

1-544684

VIII.— Oil of Turpentine. Sp. gr. 0*855. Temp. 8°*5 R.
= 10°*6 C.

1-470496

1-471530

1-474434

1-478353

1-481736

1-488198

1-493874

REPORT ON REFRACTIONS OF SOLAR SPECTRUM.

Table I. (continued).

IX.— Solution of Potass. Sp. gr. 1'416. Temp. 9° R.
= ll°-25 C.

1-399629

1-400515

1-402805

1-405632

1-408082

1-412579

1-416368

X. — Water. Sp. gr. 1*000. Mean of two experiments.
Temp. 15° R. = 18°-75 C.

1-330956

1-331711

1-333577

1-335850

1-337803

1-341277

1-344169

Table II.

Indices determined by M. Rudberg.

I. — Calcareous Spar. [Prism-edge parallel to axis of
rhombohedron.] Ordinary ray.

1-65308

1-65452

1-65850

1-66360

1-66802

1-67617

1-68330

II. — Ditto. Extraordinary ray.

1-48391

1-48455

1-48635

1-48868

1-49075

1-49453

1-49780

III. — Quartz. [Prism-edge parallel to axis of rhombohedron.]
Ordinary ray.

1-54090

1-54181

1-54418

1-54711

1-54965

1-55425

1-55817

IV. — Ditto. Extraordinary ray.

1-54990

1-55085

1-55328

1-55631

1-55894

1-56365

1-56772

V. — Topaz. 1st axis of elasticity. [Ray in direction of axis.]

1-61791

1-61880

1-62109

1-62408

1-62652

1-63123

1-63506

NINTH REPORT 1839.

Table II. [continued),

VI.-

-Topaz. 2nd axis. [Ray in direction of axis.]

1-60840

1-60935

1-61161

1-61452

1-61701

1-62154

1-62539

VII.— Ditto. 3rd axis. [Ditto.]

^1-61049

1-61144

1-61375

1-61668

1-61914

1-62365

1-62745

VIII.-Arragonite. 1st axis. [Ditto.]

1-52749

1-52820

1-53013

1-53264

1-53479

1-53882

1-54226

IX.— Ditto. 2nd axis. [Ditto.]

1-68061

1-68203

1-68589

1-69084

1-69515

1-70318

1-71011

X.— Ditto. 3rd axis. [Ditto.]

1-67631

1-67779

1-68157

1-68634

1-69053

1-69836

1-70509

Table III.
Indices determined by the author of this Report.

I.— Double-distilled Oil of Cassia at 10° Centig. [3rd series.]

1-5963

1-6007

1-6104

1-6249

1-6389

1-6698

1-7039

II.— Ditto at 14°. [3rd series.]

1-5945

1-5979

1-6073

1-6207

1-6358

1-6671

1-7025

III.— Ditto at 22°-5. [2nd series.]

1-5895

1-5930

1-6026

1-6174 1-6314

1-6625

1-6985

REPORT ON llEFUACTIONS OF SOLAR SPECTRUM.

Table III. {continued).

IV.— Sulphuret of Carbon at 15°-65. [Mean of 2nd and 3rd
series and No. ii. of 1st.]

1 •61823

1-62190

1-63083

1-64386

1-65550

1-67993

1-70196

v.— Oil of Anise at 15°-1. [Mean of 2nd series. No. iv., and
1st series, Nos. iii. and iv.]

1-54865

1-55080

1-55725

1-56590

1-57435

1-59120

1-60842

VI.— Ditto (probably altered) at 13°-25. [3rd series.]

1-5482

1-5504

1-5565

1-5650

1-5733

1-5901

1-6066

VII. — Ditto at 20°'9. [Mean of 1st series, Nos. i. and ii., and
2nd series. No. iii.]

1-54507

1-54730

1-55345

1-56235

1-57077

1-58815

1-60527

VITI.— Kreosote at 18^-2. [Mean of 3rd series and 2nd and
1st; No. i.]

1-53196

1-53353

1-53833

1-54523

1-55153

1-56390

1-57486

IX. — Oil of Sassafras at 17°*2 [Mean of 1st series. No. ii.,
and 3rd series.]

1-52575

1-52750

1-53215

1-53870

1-54485

1-55750

1-56935

X.— Sulphuric Acid. Sp. gr. 1-835. Temp. 18°' 6.
[From 1st series.]

1-4321

1-4329

1-4351

1-4380

1-4400

1-4440

1-4463

XI.— Muriatic Acid. Sp. gr. 1-162. Temp. 18^-6. [Ditto.]

1-4050

1-4065

1-4095

1-4130

1-4160

1-4217

1-4261

NINTH REPORT 1889.

Table III. {continued).

XII.— Nitric Acid. Sp. gr. 1-467. Temp
1st series.]

. 18°-6. [From

1-3988

1-3998

1-4026

1-4062

1-4092

1-4855

1-4206

XIII.— Alcohol. Sp. gr. -815. Temp. l7°-6. [Ditto.]

1-3628

1-3633

1-3654

1-3675

]-ZQ2Q

1-3733

1-3761

XIV. — Pyrolignous Acid. Temp. 16°-2

Sp. gr. 1-060.

1-3729

1-3745

1-3760

1-3785

1-3807

1-3848

1-3884

XV. — Concentrated solution of Pure Soda
Sp. gr. 1-34.

. Temp. 16°.

1-4036

1-4039

1-4075

1-4109

1-4134

1-4181

1-4221

XVI. — Solution of Caustic Potassa. Temp. 1

6°. Sp. gr. 1-42.

1-4024

1-4036

1-4061

1-4091

1-4117

1-4162

1-4199

XVII.— Rock-salt.

1-5403

1-5415

1-5448

1-5498

1-5541

1-5622

1-5691

XVIII. —Solution of Muriate of Lime.
[1st series.]

Temp. 22°-2.

1-4006

1-4016 1-4040

1-4070

1-4099

1-4150

1-4190

XIX. — Solution of Muriate of Am
Temp. 22°-2 [Ditto.]

nonia.

1-3499

1-3508

1-3529

1-3552

1-3575 1

1-3617

1-3650

XX. — Solution of Nitrate of Potassa. Temp.

22'''2. [Ditto.]

1-3457

1-3468

1-3487

1-3510

1-3533

1-3586

1-3608

REPORT ON REFRACTIONS OF SOLAR SPECTRUM.

Table III. {continued).

XXL— Solution of Sulphate of Magnesia.
Temp. 22°-2. [1st series.]

1-3434

1-3442

1-3462

1-3486

1-3504

1-3540

1-3570

XXII.— Solution of Nitrate of Mercury.
Temp. 21°-6. [Ditto.]

1-3408

1-3419

1-3439

1-3462

1-3487

1-3528

1-3560

XXIII. — Solution of Muriate of Barytes.
Temp. 21°-8. [Ditto.]

1-3398

1-3406

1-3421

1-3438

1-3435

1-3504

1-3531

XXIV.— Solution of Sulphate of Soda. Temp. 22°. [Ditto.]

1-3392

1-3398

1-3419

1-3442

1-3462

1-3499

1-3528

XXV.— Solution of Muriate of Zinc. Temp. 22°. [Ditto.]

1-3351

1-3402

1-3421

1-3444

1-3466

1-3501

1-3534

XXVI.— Solution of Nitrate of Bismuth.
Temp. 22°. [Ditto.]

1-3306

1-3315

1-3332

1-3355

1-3374

1-3410

1-3437

XXVII.— Solution of Nitrate of Lead.
Temp. 17°'8. [Ditto.]

1-3455

1-3461

1-3482

1-3506

1-3528

1-3568

1-3600

XXVIII. — Solution of Superacetate of Lead.
Temp. 19°. [Ditto.]

1-3429

1-3437

1-3455

1-3480

1-3498

1-3538

1-3571

XXIX.— Solution of Subacetate of Lead.
Temp. 15^ [Ditto.]

1-3350

1-3357

1-3373

1-3398

1-3417

1-3453

1-3481

NINTH REPORT 1839.

Table III. {continued).

XXX. — Distilled Water (the same in which the above
solutions were made). Temp. 15°- 8. [1st series.]

1-3317

1-3326

1-3343

1-3364

1-3386

1-3429

1-3448

The same with a proportional reduction for temperature, to
compare with Fraunhofer's at 18°' 75 Centig.

1-3310

1-3320

1-3336

1-3357

1-3380

1-3412

1-3441

Approximate Indices, in cases where, from the nature of the
substance, it does not seem likely that more accurate
measures can be obtained.

XXXI.— Balsam of Peru at 19°-2. [Ditto.]

1-585 1-587

1-593

1-603

1-613

1-634

1-653

XXXII.— Oil of Pimento at 19°-8. [Ditto.]

1-528

1-532

1-535

1-542

1-548

1-559

1-571

XXXIII.— Oil of Cummin at 22«-l. [Ditto.]

1-502

1-504

1-507

1-513

1-520

1-532

1-543

XXXIV.— Oil of Angelica at 21°. [Ditto.]

1-484

1-486

1-489

1-493

1-496

1-505

1-509

XXXV.— Solution of Chromate of Lead in Nitric Acid.
Temp. 18°' 6. [Ditto.]

1-369

1-372

1-374

1-376

1-379

1-384

1-389

XXXVI.— Solution of Chromate of Potassa.
Temp. 20°-2. [Ditto.]

1-351

1-352 1-353

1-357

1-360

1-364

XXXVII.— Liquid Ammonia. Sp. gr. 898. Temp. 15°.

1-345

1-346

1-348

1-350

1-353

1-355

1-360

Oxford, August 22, 1839.

Report on the application of the su?n assigned for Tide Calcu-
lations to Mr. Whewell, in a Letter from T. G. Bunt,
Esq., Bristol.

[With two Plates,]

Bristol, August, 1839.

Dear Sir,
I SEND you eleven new tide-sheets, Nos. 33 to 43, containing dis-
cussions of my new tide-gauge observations made between Sep-
tember 1837 and June 1839, together with two of the former
sheets, Nos. 25 and 29, showing the correction-curves of hmar
parallax and declination from the dock observations of 1836 and
1837. I have also added several new correction-curves to those
of lunar parallax and declination merely, on sheet No. 29, arising
out of my investigations of the solar effects on the times of
H.W. ; and my numerical calculations, undertaken for the pur-
pose of reconciling the discrepancy between the declination-
curves, numerically and graphically obtained. My suspicions
fell on the latter, as I have already informed you ; but after a
long and laborious scrutiny I found that the others were most
in fault. All the lunar correction-curves hitherto obtained were,
however, defective, for want of applying the solar correction,
the introduction of which has considerably altered and, I hope,
improved them.

From the unexplaitied residues of time and of height contained
in the sheets for 1834, 5, 6, and 7j (44^ anterior epoch,) I ob-
tained the corrections for solar effect, first in a series of 24

r8"*45 1
clination and -< o//.>-q V parallax. The solar correction was

also found by means of the numerical calculations of the times
of H.W. for 1834, 5, 6, 7? and 1838, which was calculated twice.
The results may be seen in sheet No. 29. Another arrangement
was made from the residues of time on the sheets for 1834, 5,
and G, for the declination corrections of 5°, 13°, 20°, and 25*^.
The results, which are laid down on sheet No. 29, strongly favour
the supposition that the effects of the declinations are as their
squares. My latest declination-curves on sheet No. 3 7, for 8°, 19°,
and 26°, are still more decisive ; the sum of the twelve ordinates
between the lines of 8° and 19° being to those between 19° and

NINTH REPORT— 1839.

26° as 57 : 58 by measure on the sheet, and as 57 : 60 by the
law of the squares ; differing only ^^^th from the law.

In hope of throwing some light on the question of the best
anterior epoch of decimation, considered separately from paral-
lax, I arranged the numerical errors, or residue of calculated
times for 1837 and 1838, keeping the increasing and decreasing
declinations separate, but not distinguishing north declinations
from south. I was not, however, able in this way to perceive
how any change in the declination epoch would be attended with
advantage.

An arrangement of the numerical errors in the calculated
times for 1837 into two parcels for each month, those following
a north transit in one parcel, and those following a south transit
in the other, gave the following results : —

1837.
Month.

Mean Error of calculated

time of H. W. following a

• North Transit.

Mean Error of calculated.

time of H. W. following a

South Transit.

Dock Observations.

min.

3-7 too early.
2 '4 ditto.
1-6 ditto.
2-3 ditto.
2-0 ditto.
1-9 ditto.
1-4 ditto.
3-0 ditto.
2-3 ditto.
2-5 ditto.
1-6 ditto.
2-3 ditto.

min.

37 too late.
2-4 ditto.
1-6 ditto.
2-3 ditto.
2-0 ditto.
1-9 ditto.
1 -4 ditto.
3-0 ditto.
2-3 ditto.
2-5 ditto.
1-6 ditto.
2-3 ditto.

February

March

April

May

June

July

September

October

The average of the year gives the observed time of the H.W.
following a north transit, 2*2 minutes later than the mean or
calculated time ; and of the H. W. following a south transit, 2*2
min. earlier than tlie mean.

It is quite certain that the diurnal inequality in the intervals
at Bristol is such as to make the time of a H.W. next after a
north transit, in the main, later than that of a H. W. next after
a south transit. This is evident upon the slightest inspection
of sheets 37 to 43 tide-gauge observations.

The effect of this constant of diurnal inequality is positive
when the moon's declination (four days anterior) is north ; and
negative when it is south ; or, in other words, the diurnal in-
equality in the interval is greatest when the moon has [had]

REPORT ON TIDE CALCULATIONS. 15

north declination, and least when south. Is it possible to refer
this to anj'thing but the moon's difference of distance from the
two opposite surfaces of the ocean ?

I next proceeded to discuss the observations of the times of
H.W. from my tide-gauge register, using the mean between two
equal altitudes, taken at :jth of the distance from H.W. to mean
water, instead of the actual or observed time of H.W. In the
first discussion of about twelve months' observations in this
way, made between Sept. 1837 and Jan. 1839, and laid down
on sheets 33 to 37, the anterior epoch of 44 hours was employed
as formerh\ A comparison of the lunar correction-curves from
the different epochs of 32^, 44^% and 56^\ seemed to indicate
that the epoch of 38'^, intermediate between those of 32^ and
44^, would probably afford correction- curves of parallax and
declination approximating more closely to each other, both in
form and in magnitude. At your request, I made the trial first
with about six months' observations, which, being treated in the
usual manner, yielded, after several approximations and a new
solar correction, cvirves of lunar declination and parallax of the
shape that had been anticipated, — the second loop in the decli-
nation-curves (at 8^ transit) diminishing, while that in the pa-
rallax-curves (at the same hour of transit) was increasing. An
improvement was also seen about the hours 1 and 2 of transit ;
the mean error was at the same time lessened. I next tried
(by your directions) the effect of this change of epoch on the
whole of the tide-gauge observations I possessed, equal to about
those of one year in all, and laid them down in a second series
of curves on the same sheets, Nos. 33 — 36. The solar and lunar
corrections were approximated several times, and those finally
obtained are given at the bottom of sheet No. 33. On trying
the mean error taken at every hour of transit throughout the
whole series of observations, it was found almost identical with
that before obtained from the same observations, with the old
epoch of 44 hours, viz. 2~ min. very nearly. You then requested
me to make a further trial, in order to determine, if possible,
whether the new epoch was better than the old one. To do
this properly, I found that it would be necessary to draw the
curves of observation afresh, and to interpolate the times of
transit for every 6 and 18 hours between those given in the Nau-
tical Almanac with greater nicety, namely, with second differ-
ences and decimals of minutes. I therefore made the necessary
corrections in the intervals, and laid them down anew. You know
we had proposed to use a larger number of observations in our
second trial of the comparative merits of the two epochs ; but
as it appeared, upon further consideration, that this would not

16 NINTH REPORT — 1839.

give a fair comparison, unless the same extension of the obser-
vations were also tried with the old epoch, which would have
greatly added to the labour, I determined to confine myself to
the same observations while using the epoch of 38 hours as had
been employed with the epoch of 44 hours j which was, in fact,
to go over the ground a second time with the shorter epoch,
endeavouring to avoid any small errors I might have incurred
before, such as that I have just explained. The corrections I
eventually obtained, and laid down on sheet No. 37, are, I be-
lieve, for the moon's effects a fourth approximation, and for the
sun's a third. On carefully measuring the mean residual error
after the two processes, I find a small improvement in that of the
38^ epoch, which is now 2-394 min., while that of the 44^ epoch
is 2*510 min.

Whatever may be thought of this minute difference, which
accidental circumstances may have in some degree modified, I
think no one can hesitate to give to our new curves of lunar pa-
rallax and declination a preference before those numbered 1 and
1 on sheet 29, which were considered so good only twelve
months ago. A discussion of heights would probably afford
additional evidence in favour of our new epoch ; as there is lit-
tle doubt that the maximum height would fall much nearer than
formerly to the hour of 0^ transit ; though I believe it will now
be a little to the right hand of that hour line, as though the
epoch were rather too much shortened. If similarity of form
between the parallax and declination correction- curves be ad-
mitted as the proper test of the anterior epoch, it is pretty evi-
dent that 38^ is better than any other that we have yet tried.

The observations of displacement of summit of the tide-
curves, or differences of equal altitude-times, and actual times
of H. W., are laid down on sheets Nos. 33 — 36, and the result-
ing corrections on No. 33. The observations are continued from
January to June, on sheets Nos. 42 and 43. I had transferred all
these observations to a separate sheet, and begun to discuss
them afresh : but seeing no reason for thinking I could throw
any further light on the subject just at present, I laid it aside
until more observations had been made, or until you had favoured
me with your opinion as to the best mode of proceeding.

You will be pleased at hearing that Dr. Carpenter's exertions,
so ably seconded by your letter, have succeeded in procuring a
grant of 50/. from the Corporation, in addition to a previous
one of 20/. from the Society of Merchants, since increased to
25/., making together ^-^l-i which has been paid me in consi-
deration of my time and labour bestowed on attending to the
tide-gauge, and calculating a tide-table annually for the port.

REPORT ON TIDE CALCULATIONS.

These grants are donations only : but it has been intimated to
me that they may be repeated.

A few days ago I laid down the Bassadore intervals, which
you have copied into your paper, for the sake of looking at the
enormous diurnal inequality which appears in them. I have not
the diagram at hand, but I remember being struck with the great
disparity between the acceleration of the time of H. W. after a
given transit — say the superior, — when the moon was on 07ie
side of the equator, and the retardation when she was on the
other ; thus : —

These observations having been made in the month of No-
vember, a part of this disparity may perhaps be due to the sun,
which has then considerable south declination ; but if the same
thmg be observed in the summer months, shall we not have
here another case similar to that of Bristol, where the H. W.
next after a south transit is, about three times out of four all
through the year, earlier than that after a north transit, as I
have already remarked ?

I am. Dear Sir, &c.

T. G. BUNT.

In the Philosophical Transactions for 1839, Parti, page 151,
will be found a further discussion of observations of high and
low water at Plymouth, showing that the height of mean water
at that place is nearly permanent; also a comparison of the
high and low water at Leith, showing that at that place the
height of mean water is still more nearly permanent, the varia-
tion being only a very few inches.

The accompanying curves (Plates III. and IV.) exhibit the
results of the equal altitude observations referred to in Mr.
Bunt's letter. The times of H. W. here employed are not the
moments when the water is observed to be highest, but the mo-

18 REPORT— 1839.

ments obtained by bisecting the times at which the water is at
three-fourths the height of H. W. above the level of mean water,
during the rise or the fall of each tide. The corrections are ar-
ranged according to the hour of the moon's transit, and repre-
sented on a scale of forty minutes to an inch. The transit of the
moon here employed is not the one immediately preceding the
H. W., but, in the first figures, it is the one a day and a half
previous to that which precedes the H. W. ; that is, the transit
B of Mr. Lubbock. In the latter figures, constructed from
thirty-eight hours' anterior epoch, an epoch or transit is em-
ployed, interpolated midway between B and C, which appears
in some respects to give better results than either of those two
transits.

The curves entitled displacement of Summits express the dif-
ference of time of H.W. as actually observed, and as inferred by
bisection of the interval of equal altitudes just described. This
difference shows itself in the displacement of the summits of the
curve, which exhibits the rise and fall of the water on Mr. Bunt's
machine. It is a remarkable and not very easily explicable cir-
cumstance, that this displacement appears to be more affected
by solar parallax than by any other element. When the dis-
placement is such as to accelerate the time of H. W., the fall
of the tide is less rapid, and when such as to retard the time of
H.W., the fall is more rapid than the rise.

W. Whewell.

Notice of Determination of the Arc of Longitude between the
Observatories of Armagh and Dublin. By the Rev. T. R.
Robinson, D.D., &^c.

At the Edinburgh Meeting of the Association, a Committee was
appointed to determine, by chronometers or signals or both, the
longitudes of the principal observatories of the British Isles,
and its members were authorized to apply to the Government
for any aid that might be necessary. Cambridge and Oxford
present no peculiar difficulty, but the observatories of Ireland
and Scotland, both from distance and local circumstances, are
less easily managed. The chronometric part of the process has,
however, been most effectually performed by one of our mem-
bers, Mr. Dent, who, in the first instance, sent twelve of his
chronometers from Greenwich to Edinburgh and Makerstown,
(the observatory of Sir Thomas Makdougall Brisbane) : they were
returned again to Greenwich, and Professor Henderson has de-
duced from the results,

m s

Longitude of Edinburgh +12 42*99
Makerstown + 10 3-66

These results were reported at the Newcastle Meeting by Sir
Thomas Brisbane, and they inspired Sir W. Hamilton and my-
self with the desire of obtaining a similar determination of our
longitudes. Mr. Dent not merely placed these chronometers at
our disposal, with three additional, but bestowed what was even
more precious, his personal attendance, and assisted us in the
comparisons ; an advantage which could not have been pur-
chased, but which I notice as an instance of the aids which
these meetings afford to Science.

Twelve of the chronometers were rated as before at Greenwich
Observatory, the three others at the Marine School ; and Mr.
Dent, setting out on the evening of September 20, was enabled
by the rapidity of railroad travelling to compare them at Dublin
on the morning of the 22nd, and on that of the following day at
Armagh, having travelled about 500 miles. His return was ef-
fected with equal rapidity, and I have deduced from the com-
parisons,

m s

Longitude of Dublin + 25 21-08
Armagh + 26 35-44
c2

20 REPORT— 1839.

which, however, cannot he regarded as definitive until the per-
sonal equations of the Irisii observers shall have been compared
with those of Greenwich.

The extreme consistency of the individual results, the great-
est differetice being 1^-65, is well calculated to inspire confi-
dence, and there is every reason to rest satisfied with these num-
bers, as the chronometric longitudes.

Yet, however accurate they be, it is impossible to consider
the means by which they are obtained as superseding the me-
thod by signals. The first, transports the time from one station
to another by machines, which, though their performance is
wonderful, yet must be disturbed by that very process ; in the
second, the chronometer is light. Its application is far more
costly as well as difficult, but its certainty is greater, and the
whole of the disturbing causes are in view. The general cha-
racter of it is this, — The flame of powder at an intermediate sta-
tion is observed from the observatories, and the difference of the
times is that of longitudes. If, however, the interval is too great
for one signal, two with an intermediate observer are employed :
the eastern signal is observed by him and the eastern observa-
tory ; a short time after he observes the western signal in con-
junction with the west observatory, and the longitude is the
difference of observatory times, lessened by that which has
elapsed between the two signals. Thus any number of inter-
mediate stations may be employed. The powder is generally
fired on mountains, and it is found that the flash of small quan-
tities is visible at very great distances. Four ounces have been
seen at 140 miles. When mountains are not to be found, the
requisite height must be gained by rockets ; and an elegant ap-
plication of this is seen in Sir J. Herschel's operations for de-
termining the relative longitude of Greenwich and Paris, de-
tailed in the Philosophical Transactions for 1826.

This kind of signals is essential in Ireland, and even with
them the local circumstances of Armagh are such as to present
great difficulties. A range of hills rises to the south, from 600
to 1000 feet above it, at about four miles distance, and these are
shut out from Dublin by high ground to the north of it. I was
deprived of the aid of Colonel Colby, by his absence in Scotland,
where he was engaged in making the necessary arrangements for
the completion of its survey, but my friend Lieut. Larcum sup-
plied all necessary information, guided by which the mountain
She-. e Gullion was selected. Its summit is visible from Dublin
at fifty-two miles, but is 800 feet below the land which bounds
my view, and this decided the size of the rockets necessary, as, be-
sides certainly clearing tliat ridge, they were to carry four ounces

ARMAGH AND DUBLIN ARCS OF LONGITUDE. 21

of powder. The two-pounder is necessary for this, and, on sta-
ting my objects, a liberal supply of them was ordered by the
Board of Ordnance, together with tents for the firing parties ;
and, indeed, whatever I required was freely afforded. Without
dwelling on details, it may be sufficient to mention that on four
nights in May last, notwithstanding most unfavourable weather,
we obtained from seventy-four signals, forty-two good results :
from which we deduce our difference of meridians to be

m s

1 14-425;
only three-hundredths of a second greater than Mr. Dent's
chronometers had given.

In taking this mean, it is necessary to attend to the different
value of the work of each night, which varies according to tlic
number of signals observed, and that of the stars observed for
time. This has been done according to the theory of probabili-
ties, in applying which it was found that the probable error of
time-determination by a star is about 0*065, and by a rocket
0*16. It also appears, that when several intermediate stations
are used, the value of the result is rapidly diminished ; so that,
for example, if as in Sir J. Herschel's operations between
Greenwich and Paris, we suppose three stations — ten signals at
each, and seven stars to determine time at the extremities, the
worth of such a result is but 0-38 of what it would be if the
work could be done by one signal station. If to this we add the
great uncertainty of perfect transmission along the line, it be-
comes an object to increase the extent of distance connnanded
by each signal as much as possible.

To complete the result, it is necessary to know the *' personal
equation" of the observers, or, in language fit for the uninitiated,
the difference of the times at which two observers estimate the
passage of a star over a transit-wire, — such a difference as
astronomers well know almost always exists, and sometimes to
a startling extent. By a journey to Dublin, my assistant deter-
mined that he observed 0*167 earlier than the other observer,
and therefore the true difference of longitude is

m s

1 14-258
It is our intention next, to determine the longitude of the
third great Irish observatory, that which Mr. Cooper is fur-
nishing with instruments of unexampled magnitude and power,
which can be connected by one station with this and Dublin
simultaneously. That I hope to follow up by a similar opera-
tion between Armagh and Edinburgh, if, as I expect, the Board
of Ordnance prove as propitious to my second application.
Rockets of sufficient power fired on Goatfell in Arran, can be

22 REPORT— 1839.

seen by these observatories, distant 105 and 85 miles. They
must, however, rise 1100 yards, while those used by me as-
cended from 600 to 800 yards only ; but this is a range quite
within reach of Woolwich pyrotechny. Several which I lately
made, not exceeding two pounds, rose with the same heading,
from 1200 to 1500 yards ; and, judging from the range of Eng-
lish war-rockets, their ascent would be even greater. If they
be supplied, it would be an object of no common interest to see
the instruments of carnage and terror dovoted to the ministry of
science. The flash of powder can be seen at even greater di-
stances than those named, but its flame is far less brilliant than
many other pyrotechnic compositions, some of which I find are
thrice as luminous. If this attempt succeeds, the junction of
Dublin with Oxford, by signals on the Welsh mountains, is not
more difficult ; and perhaps even the connection of Greenwich
and Paris, by a single station, is not impossible.

T. R. Robinson.

Report of some Galvanic Experiments to determine the exist-
ence or no7i-existence of Electrical Currents among stratified
Rocks, particularly those of the Mountain Limestone forma-
tion, constituting the Lead Measures of Alston Moor. By
H. L. PattinsoNj Esq.

At the meeting of the British Association held last year in
Newcastle-upon-Tyne, I had the honour of being intrusted with
a grant of money for the purpose of making some experiments
to determine if any appreciable galvanic action existed among
stratified rocks, but I had more immediately in view to experi-
ment upon the alternations of strata found in the Lead Districts
of Northumberland, Cumberland, and Durham. There was as-
sociated with me in this inquiry my friend, Mr. Thomas Ri-
chardson of Newcastle, but he was prevented giving me his
assistance at the time required. Mr. John Leathart of Alston
then offered to assist me, and I gladly availed myself of his co-
operation, the more valuable because his residence on the spot
enabled him conveniently to make some necessary arrangements
which would otherwise have occasioned me nmch trouble.

In the Lead District to which I have alluded, the mountain
limestone alternates with indurated clay and sandstone (called
technically Plate and Hazle,) with remarkable frequency and
regularity. A section of the strata in this part of the country
was published in 1800 at Carlisle, by W. Miller, miner, but
a far more complete and accurate section was published by
Mr. Westgarth Forster in 1809, which is to be found also in the
forty-fifth volume of the Philosophical Magazine. The following
statement of the ' lead measures' of Alston Moor is copied from
Mr. Forster. Its general correctness I have had frequent op-
portunities of verifying.

yds. ft. in.

Fell top limestone 116

Coal 00 8

Hazle, or upper coal sill . . 4

Plate 10

Hazle, or whetstone sill . . 3

Plate 4 00

Hazle 400

Plate 2 10

Carried forward 29 2

yds. ft. in.

Brought forward. ... 29 2

Upper slate sill 8 00

Plate 2 16

Lower slate sill 7 00

Plate 10

Hazle 3

Slate 7 00

Iron stone and coal 116

Carried over .... 68 2

REPORT 1839.

Brought forward

Fire stone

Plate

yds. ft. in.

.68 2
.11
.800
2
1

Hazle 3

Plate 4

Hazle 2

Plate 4

Hazle, called Pattinson's

sill 4

Plate 6

Little limestone 3

Plate 6

Sulphureous coal

Hazle, called High Coal Sill 4

Plate 2

Sulphureous coal

Hazle, called Low Coal Sill 3

Plate 6

Carried forward 158 2

yds. ft. in.

Brought forward 158 2

Hazle, called the Tuft 3

Plate 7 00

Limestone 1 6

Quarry hazle 10

Plate 11

Harder Plate, called Till

Bed 2 1 6

Four fathom limestone. ... 800

Nattrap Gill hazle 6

Plate ,110

Three yards limestone .... 300

Six fathoms hazle 12

Plate 3 1 G

Five yards limestone 2 1 G

Slaty hazle 4 00

Plate 6 00

Scar limestone 10

Plate 10

259 2

In considering these numerous alternations it is easy to
imagine that they in some measure resemble a voltaic pile, and
the conjecture not unnaturally arises, that possibly some gal-
vanic action may be exerted among them. It is easy to speculate
further, that the veins traversing these strata perpendicularly,
may possibly act as electrodes, and that their metallic and other
contents differing so much from the rocks in which they occur,
may be drawn together and collected by galvanic currents ex-
cited by the strata and circulating in the veins. These views
and suppositions are not at all new ; they have been put forth
on different occasions in various publications of the day, but as
far as I know, up to the present time, have never been sub-
mitted to the test of experiment. I mean the galvanic action of
stratified rocks has not been before tested by experiment, for
Mr. Fox has undoubtedly shown that galvanic currents do exist
in some veins.

I have briefly to lay before the Association an account of the
experiments performed by my colleague and myself on this sub-
ject, which, if they have not cleared up the matter, have at least
drawn the uncertainty within smaller bounds.

Our first experiment was to determine if any difference ex-
isted in the electrical condition of the limestone stratum, called
the Great Limestone in Forster's section, and a soft sandstone,
called the Tuft, lying immediately under it, the under surface
of the limestone and the upper surface of the sandstone being

GALVANIC EXPERIMENTS. 25

in contact. The experiment was performed in an adit or level,
driven partly in each of these strata, at a mine called White Well,
near Alston, and the spot selected was at a distance from any
vein. We proceeded by fixing, about twelve inches above the
under surface of the limestone, in holes bored for the purpose,
twelve hollow copper cylinders, each five inches long by one
inch diameter, which were firmly secured in the holes and forced
strongly into contact with the rock by means of wooden plugs
driven within the cylinders. With these cylinders a copper wire
one twentieth of an inch in diameter was connected, and one end
of this wire was attached to one end of the wire of a delicate
galvanometer. In the same way twelve copper cylinders were
inserted in holes made in the sandstone, about a foot from its
upper surface, and to these were attached a similar wire, which
was brought in contact with the other end of the galvanometer
wire, so that any current between the two strata would be im-
mediately perceived by its action upon the needle. On making
the contacts, no motion whatever was produced on the needle,
and every expedient for increasing the eft'ect of a feeble action
was resorted to, such as making contact at short and equal in-
tervals, the interval being the time required for one vibration of
the needle, which was previously determined. At the same time
the sensibility of the instrument was such, that a plate of zinc
and a plate of copper, each one eighth of an inch square, in
pure water produced a most distinct action. The galvanic
action, if any existed between this limestone and sandstone
stratum when the experiment was performed, was, as col-
lected by the metallic surfaces in contact with each, decidedly
less than that of a pair of zinc and copper plates, each one
eighth of an inch square, in pure water.

The next experiment was upon a stratum of limestone and a
stratum of hazle, having a plate bed between them, and the
situation selected was a shaft near Alston, called Water Greens
shaft, sunk by the Commissioners of Greenwich Hospital some
years ago into Nent-force level. The strata sunk through in
this shaft, as shown in the Hospital books, are as below; it is in
the lower part of the series just given from Forster's section,
the beds differing a little from the thicknesses stated by him,
as they almost always do when measured at different places.

yds. ft. in. yds. ft. in.

Clay 10 10

Part of six fathoms hazle . . 7 2

Hard plate 100

Five yards limestone 3 1 6

Hard plate 1 6

Hazle 800

Carried forward .... 3100

Brought forward. . . .
Plate

31
... 300

Scar limestone

Hazle

... 18 6
. . . 2

Plate

Hazle

... G 1 6
... 200

61 1

26 REPORT — 1839.

The limestone pitched upon for this experiment was that
called the Five Yards Limestone, and the sandstone the Six
Fathoms Hazle, the plate bed between them being three feet in
thickness and a little more strongly indurated than the plate
beds in the district usually are. There was a flooring or hunyan
across the shaft at this place, and a level or drift driven out of
the shaft to a small distance, in which the galvanometer was
placed. The situation was at a distance from any vein, and all
the circumstances were of the most favourable nature for per-
forming the experiment with the utmost completeness and pre-
cision.

Six holes, each two feet deep, were bored in the sandstone a
foot above its under surface, and six similar holes were bored in
the limestone a foot below its upper surface ; into these holes
were introduced twelve slips of sheet copper, each two feet long
by two inches wide, bent so as to be semi-cylindrical, and they
were fixed and stemmed very tightly into the holes so as to se-
cure the most perfect contact. The six copper slips in the hazle
were connected with a copper wire one twentieth of an inch in
diameter, the end of which, as before, was attached to one pole
of the galvanometer, and the six coppers in the limestone were
similarly connected together and brought in contact with the
other pole of the galvanometer. Every possible care was taken
in attaching the wires and in making the contacts, but the needle
of the galvanometer did not show the slightest current, although
at the same time it was fully sensible to the action of the plates
of zinc and copper, one eighth of an inch square, in pure water.
When the contacts were made at intervals so as to be isochro-
nous with the times of vibration of the needle, and continued for
several minutes, there was still no appreciable effect whatever.

It was thus fully established that under the circumstances
detailed, there was no current given off equal in amount to that
excited by a pair of plates of zinc and copper, one eighth of
an inch square, in pure water ; indeed, when we reflect upon the
thickness and imperfectly conducting nature of the strata, no
very obvious current could be expected. It is, however, still
possible that, by using a more delicate galvanometer, bringing
into contact with each stratum a larger surface of metal, and
including a greater number of alternations of strata within the
circuit, a current may yet be detected, and the matter is certainly
open for further investigation.

Bensham Grove, Gateshead. August 24th, 1839.

Report respecting the tivo series of Hourly Meteorological Ob-
servations kept in Scotland, at the expense of the British
Association. By Sir David Brewster, K.H. LL.D.
F.R.S. L. & E.

Having fixed upon Inverness and Kingussie as two suitable
stations for carrying on the two series of hourly observa-
tions, which I undertook to establish and superintend for the
British Association, I was fortunate in being able to prevail
upon the Rev. Mr. Rutherford of Kingussie, and Mr. Thomas
Mackenzie, teacher of Raining's school, Inverness, to undertake
these observations. The instruments which were necessary for
this purpose were made by Mr. Adie of Edinburgh, under the su-
perintendence of Prof. Forbes, and the observations commenced
on the 1st of November, 1838, the beginning of the Meteorolo-
gical year, or the first of the group of winter months. I directed
the two observers to pay particular attention to the aurorce
boreales, and to record every phaenomenon of this nature ; and
I have no doubt, from the lists already sent me, that this class
of observations will be the most complete and valuable that
has ever been made in Scotland.

I annex a specimen of the observations made at Kingussie
at the time of the great depression of the barometer on the
29th November, 1838, which will exhibit the nature and value
of the register.

As it is of the greatest importance to obtain the true curve
of the daily variation of temperature and pressure at the two
stations of Inverness and Kingussie, the last of which places
is between 700 and 800 feet above the level of the sea, I
earnestly hope that the Association will permit these observa-
tions to be carried on for at least another year.

An Extract

REPORT — 1839.

An extract from the Register of the Thermometer and Ba-
rometer kept at Kingussie by the Rev. A. Rutherford.

s
1

27th November, 1838.

s
1

28th November, ]838.

Weather.

1a.m.

2775

28°880

Clear, calm.

8 P.M.

39°05

27°582

Rain, windy, S.E,
ditto

28-846

ditto

27-488

28-834

Clear, windy, W.

41-75

27-460

ditto

27-75

28-810

ditto

27-424

ditto

27-75

28-776

ditto

27-426

ditto

36
35
35
36
36

7
8
9
10

29-50
30-50
31-50
32-75
34

28-734

28-680
28-676
28-636
28-620

ditto

ditto, wind S.

ditto

29tli November, 1838.

1a.m.

43-50
44

27-438
27-412

Partlyclear,windS.E,
ditto

36
36

11
12

34-50
35-25

28-608
28-580

ditto
ditto

45
44

3
4

43-75
43-50

27-396
27-390

Cloudy, squalls,
ditto

1 P.M.

28-560

ditto

43-50

27-386

ditto

36-50

28-538

ditto

35-75

28-478

ditto

42-50

27-364

ditto

28-464

ditto

42-50

27-334

ditto

28-474

ditto

41-50

27-334

ditto

28-480

ditto

42.75

27-334

Rain, wind S. E.

7
8

36
35-50

28-464
28-524

ditto
ditto

45
45

11
12

42-75
42-25

27-292
27-264

Cloudy, ditto
ditto

38
39

9
10

36
36-25

28-432
28-454

ditto
Partly clear, calm.

44
44

IP.M.

42
44

27-220

27-208

ditto
ditto

28-428

ditto, gusts of wind

27-200

ditto

35-75

28-426

ditto

45
45

4
5

44
43-75

27-216

ditto

27-220

ditto

28tli Novell

iber, 1838.

43-75
43

27-220
27-232

ditto
ditto

1 A.M.

28-368

Cloudy,windy,S.E,

43-75

27-244

Cloudy, wind S. E.

28-364

ditto

43-50

27-280

ditto

37-50

28-340

ditto

42-75

27-270

ditto

28-316

Cloudy, calm.

27-270

Light clouds, S. E.

38-50

28-286

ditto

43-50

27-264

ditto

37
38-75

28-268
28-220

ditto
ditto

30th Novem

ber, 1838.

40
40

38-50
38-50

28-230
28-196

ditto
ditto

1a.m.

43-50

27-236

Cloudy, calm.

4.050

28-142

Cloudy, S, E.

43-50

27-264

ditto

41-50

28-108

ditto

27-256

Raining, ditto

41-50

28-054

ditto

27-268

ditto

1 P.M.

28-084

Rain, windy, S. E.

41-50

27-312

Fair, ditto

40-25

27-938

ditto

27-326

ditto

41-25

27-882

Fair, ditto

27-346

ditto

41-50

27-826

ditto

43-50

27-492

Drizzling, wind W.

41-75

27-812

ditto

After til is the

ditto

40-25

27-672

Rain, windy, S. E.

bar. rose rapidly
to its usual

ditto

39-75

27-624

ditto

height.

ditto

Mats at the end of November. — From the 27th till the 30th only i inch of rain fell,
notwithstanding the low state of the barometer. The depression seems to have
been more the result of high gusty winds, and probably falls of rain, or other
commotions in the neighbourhood, than any immediate fall here.

HOURLY METEOROLOGICAL OBSERVATIONS. 29

Azotes of the Appearance of the Aurora Horealis.

13th November, 2 o'clock, a.m., aurora till 6 o'clock, a.m.

The following are the more minute details.

Having been awakened by the assistant at a quarter to 2
A.M., I found a rather bright aurora, consisting of an arched
bend from N.E. to N.W., with a few streams of light darting
up to the zenith. There were also a few light clouds floating
along the northern horizon, with a haze of light on the back
ground. At 3 a.m., streaming up very bright, bend as for-
merly, light clouds over the aurora. At ^ past 3 a.m., very
bright. Besides the arched bend formerly mentioned there
was another dimmer arch higher up, extending from a little
to the North of East, quite across the sky to a little North of
West, its upper border reaching the seven stars or pleiades.
Between these two arches there were a great many spires of
light darting up and recoiling, with frequently a sort of M^aving
flash running over the slightly illumined parts, and even where
no spires of light were visible, except where the flash gave
them a momentary existence ; clouds on the horizon, but not
many. 25 min. to 4 a.m., a few clouds on the horizon, and a
bright arch above them, but few spires of light. ^^ to 4 a.m.,
as last noted, but streaming more up to the zenith. 4 o'clock,
AM., a few clouds in the N.W. horizon 5 the light dim, few
spires, and these extending only a short way up the sky. ^
past 4 A.M., as last noted, with an arch of light a little above
the horizon, right over North, and spires of light darting up.
^ past 4 A.M., ditto, ditto. ^ to 5, a.m. few clouds, but a
dark colour below the arch near the horizon. 5 a.m., clear
coruscations flashing up to the zenith, the upper edge or arch
passing through it, or nearly so, from N.E. to about due W.,
touching Orion's belt with its upper border. Flashes of light
rolling from W. to E., illuminating lines of the aurora perpen-
dicular to the lower arch, and reaching the higher one, but
only rendered visible by the coruscations passing over them.
The aurora brightest where there are clouds on the horizon.
No wind nor frost, although clear, except the few clouds men-
tioned. I past 5 a.m., coruscations from the horizon up to the
zenith in a hobbling manner. 6 o'clock, only a dim light.

17th November, 1838, 10 o'clock, p.m., slight aurora, but
not visible at 1 1 p.m.

14th December, ditto. 9 o'clock, p.m., slight ditto, tops of
the spires only visible above the horizon in the north. 1 1 p.m.
only a dim light.

St. Leonard's, St. Andrew's. August 22nd, 1839.

Report on the subject of a series of Resolutions adopted by the
British Association at their Meeting in August, 1838, at
Newcastle, to the following effect : —

" Resolved. 1. That the British Association views with high
interest the system of simultaneous magnetic observations
which have been for some time carrying on in Germany and
various parts of Europe, and the important results to which
they have already led, and that they consider it highly desirable
that similar series of observations, regularly continued in cor-
respondence with, and in extension of, these should be insti-
tuted in various parts of the British dominions.

" 2. That this Association considers the following localities
as particularly important : — Canada, Ceylon, St. Helena, Van
Diemen's Land, and Mauritius or the Cape of Good Hope ; and
that they are willing to supply instruments for their use.

" 3. That in these series of observations the three elements
of horizontal direction, dip, and intensity, or their theoretical
equivalents be insisted on, as also their hourly changes, and on
appointed days their momentary fluctuations.

" 4. That the Association considers it highly important that
the deficiency yet existing in our knowledge of terrestrial mag-
netism in the southern hemisphere should be supplied by ob-
servations of the magnetic direction and intensity, especially
in the high southern latitudes between the meridians of New
Holland and Cape Horn, and they desire strongly to recom-
mend to Her Majesty's Government the appointment of a
naval expedition expressly directed to that object.

"5. That in the event of such expedition being undertaken
it would be desirable that the ojGficers charged with its conduct
should prosecute both branches of the observation alluded to in
Resolution 3, so far as circumstances will permit.

" 6. That it would be most desirable that the observations so
performed, both at the fixed stations and in the course of the
expedition, should be communicated to Professor Lloyd.

" 7. That Sir J. Herschel, Mr. Whewell, Dr. Peacock, and
Professor Lloyd be appointed a Committee to represent to
Government these recommendations.

" 8. That the same gentlemen be empowered to act as a
Committee, with power to add to their number, for the purpose

32 REPORT — 1839.

of drawing up plans of scientific co-operation, &c. relating to
the subject, and reporting to the Association.

'^ 9. That the sum of 400/. be placed at the disposal of the
above-named Committee for the above-mentioned purposes."

The Committee named in the above-mentioned Resolutions
report, —

That in pursuance of the instructions conveyed in Resol. 7?
they immediately proceeded to address a copy of the Resolu-
tions to His Grace the Duke of Northumberland, President of
the Association, for signature, with a request that he would
forward it so authenticated to Lord Melbourne, accompanied
by a letter from Sir J. Herschel, soliciting an interview on the
part of the Committee, for the purpose of entering into the
necessary explanations. His Grace having most readily com-
plied with this request, a reply was after some time received
from Lord Melbourne to the following effect : —

" Sir " Windsor Castle, September 3, 1838.

" I BEG leave to acknowledge your letter of the 27th ult., and
to acquaint you that I shall be most happy to receive the
Committee of the British Association for the Advancement
of Science upon my return to London ; and remain. Sir,
"With great respect,

" Your faithful and obedient Servant,
" Melbourne."
" Sir J. Herschel, Bart.,
10, Hanover Terrace, Regent's Park."

By a subsequent communication from his lordship the inter-
view in question was deferred until the Chancellor of the Ex-
chequer could appoint a day for attending. At length Saturday
the 10th November was appointed ; but the last mentioned
minister not being then able to attend, his lordship declined
considering the interview as official, allowing the Committee
however to place in his hands for consideration a memorial, of
which the following is a copy.

Memorial of the Committee appointed by the British Associa-
tion for the Advancement of Science, to submit to Her
Majesty's Government the Resolutions of that Association
on the subject of Terrestrial Magnetism.

The instruments and the methods of observation hitherto
employed in determining the dip and variation of the magnetic
needle, whether at fixed stations, or in surveys and voyages of

TERRESTRIAL MAGNETISM. 3.5

discovery, have been such as to afford results incapable of beinaj
depended on to any minute degree of precision, calculated only
to satisfy the immediate practical wants of the ordinary na-
vigator ; and, so far as theory is concerned, to give a general
view of the course of the magnetic lines in those parts of the
globe which have chiefly been the scenes of inquiry, and to es-
tablish the important facts of changes more or less rapid taking
place in the intensity and direction of the magnetic forces at
every point of its surface.

Of late, however, methods infinitely more perfect have been
devised and practised in Germany (whence their use has ex-
tended to other nations in Europe), which have given to mag-
netic determinations a precision previously supposed to be un-
attainable — a precision not inferior to that of astronomical ob-
servation. The time is therefore now arrived when all that is
rude and inexact in the subject of terrestrial magnetism must
give place to rigorous numerical statement and refined discus-
sion ; and, when a theory can exist, which, like those of the
planetary movements, basing itself on a few perfectly ascer-
tained elements, shall embrace in general formulae all the in-
tricacies of the subject — define a priori the course of the mag-
netic lines over the whole surface of the globe, and retrace or
predict their variations for centuries past or to come.

To ascertain these elements with all the strictness which
human skill and industry can command ; to investigate, by
systematic, and, when necessary, by co-operative observation,
those inductive laws which must serve as the stepping stones of
such a theory, and to amass a series of well concerted and ef-
fective observations, of sufficient accuracy and extent to serve as
tests of its truth — have appeared to the British Association for
the Advancement of Science objects of such eminent importance
as to justify it in recommending them to Her Majesty's Go-
vernment, as worthy of some considerable national exertion
and expenditure. Private research has done much, and is
doing more, and the practical bearings of the subject may
possibly stimulate commercial bodies to afford some slight
and incidental aid in the inquiry ; but there are features in the
case which lead us to conclude that without the co-operation
of Government on an extensive scale, the resources of science
must be employed in vain, or a^ a disadvantage which must
retard indefinitely the desired consummation.

For, in the first place, the observations necessary for the
purpose in view require to be made at many very distant points
of the globe, for a considerable length of time, and (what is
particularly to be noticed) at moments strictly simultaneous.

1839. D

34 REPORT — 1839.

This precludes all hope that individuals going about the world
from station to station may, by slow degrees, at length amass the
information required. It has been ascertained that the mag-
netism of the globe is liable to sudden and transient distur-
bances, which, so far as appears, are strictly contemporaneous
over great districts, and not improbably over the whole surface
of the earth. Hence arises the necessity of employing no ob-
servations but such as are strictly simultaneous in combinations
destined to elicit the values of the magnetic constants, since
otherwise the resultant of forces in action at a given point of
the globe would be brought into comparison with that of forces
which have ceased to act in another point, and thus the in-
fluence of local situation would become confounded with that of
temporary change.

Observations prosecuted on such an extensive scale, and so
strictly in concert, are altogether beyond the reach of individual
zeal and enterprise. They demand a systematic organization
and official responsibility quite as much as an outlay of funds,
and it is with a view to this that the Association has agreed to
the 1st, 2nd, and 3rd Resolutions, which recommend the esta-
blishment of what may be called Primary Magnetic Stations, at
the places therein named, at points most convenient and appro-
priate for combination with the European stations already in
activity, including those of Greenwich and Dublin.

In concert with such primary stations, it would be both natu-
ral and highly desirable that travellers provided with the requisite
instruments, or officers in other stations who may be willing to
devote a portion of their time to this service, and who may for
that purpose be temporarily provided with the instrumental
means, should act. Every such primary station then, suppos-
ing such to be established, would henceforth become a point of
reference and comparison, by which short and desultory series
of observations in other localities might be rendered available ;
including under this head such as might be made in the course
of nautical surveys and voyages of discovery, or where from
other causes it might be impracticable to remain for any con-
siderable time. And it must not be forgotten that from the
very peculiar nature of the case, the observations at any one
such primary station would be a check upon the fidelity of those
made at every other By the help also of such corresponding
observations, continued with regularity and steadiness during
some considerable length of time, we should be able to ascer-
tain whether the means they suggest of determining the dif-
ferences of longitude of different stations be really practicable
and capable of extension over the whole surface of the globe.

TERRESTRIAL MAGNETISM. 35

Should this turn out to be really the case, it would be a colla-
teral result of no small practical value, being in effect a new
and general means of ascertaining the longitude^ at least of
places on land.

But although the ancient methods of observation are super-
seded for the nicer purposes of theorj^,by themore refined methods
above alluded to, it by no means follows either that the results
to which they have led are to be thrown aside as useless, or the
methods themselves rejected, when the object is not to attain the
last degree of numerical accuracy, still less when these more re-
fined processes are impracticable, as they are at sea, where,
nevertheless, it has been shown by Erman and others that the
dip and intensity, as well as the variation, can be observed with
a considerable approximation.

It has been, and must ever continue to be, the peculiar pro-
vince of these ruder ordinary processes, to trace out by actual
visitation of every accessible spot on the globe, those important
curves which, when laid down on charts, express to the eye
general relations, such as theory must exercise itself in render-
ing account of ; and, following them through all their intricacies,
must find its first application in showing how they originate in
the relations of the forces in action. These curves are in fact
no other than approximative expressions of those inductive
laws above alluded to, and will play the same part in a strict
general theory of terrestrial magnetism which Kepler's laws do
in that of gravitation, or the polarized figures do in that of
light.

A glance at the best and most approved charts, of varia-
tion and intensity, will show how much is wanting to render
this precursory knowledge complete. However, in all easily
accessible regions of the globe the investigation is proceeding
with rapidity, nor is there any desirable information of this
nature in such regions, which the diligence of navigators, sur-
veyors and travellers, in the pursuit of their ordinary objects,
will not adequately furnish. The case is otherwise with those
difficultly accessible regions, in which, unfortunately, lie the
most characteristic, critical, and important points and inflexions
of the curves in question, viz. the points of greatest intensity,
and those in which the needle points vertically dovvnwards, and
which are usually known by the name of the magnetic poles.
Two such points of greatest intensity are known to exist in the
northern hemisphere, one in Siberia, and the other in the terri-
tories of the Hudson's Bay Company ; the existence of the
first has been proved by the voyages and travels of Hansteen,
Due, and Erman ; and of the other, by the observations made

D 2

36 REPORT— 1839.

in the voyages of arctic discovery. In these voyages also, as is
well known, one locality, where the dip of the needle is 90°,
has been visited and determined by Captain James Clark Ross :
and it is the opinion of some philosophers that this may not be
the only point in the northern hemisphere where the direction
of the dipping needle is vertical, and the intensity of the hori-
zontal force consequently evanescent.

But, when we turn to the antarctic regions, we find nothing
decisive or determinate. There are no continents admitting of
overland exploration, and the seas, which must be the scene of
inquiry, are visited by no commercial enterprise, and traversed
by no casual vessels belonging to the British or any other navy.
Nevertheless, it is vain to hope for a complete magnetic theory
till this desideratum be supplied. The unsymmetrical form of
the magnetic curves will baffle every attempt to reduce them
under general laws, and will remain, as at present, an object of
idle wonder, until these points, which may be looked upon as
the keys to the enigma they offer, shall have been ascertained.
It is on this ground that the Association have agreed, in their
4th Resolution herewith submitted, to recommend to Her Ma-
jesty's Government the appointment of an expedition expressly
destined to the investigation of the magnetic phaenomena of the
antarctic regions.

The magnetic pole (or poles) of the southern hemisphere are,
in all probability, inaccessible, but this does not prevent their
situations being ascertained with tolerable precision by the con-
vergence of the magnetic meridians in their neighbourhood ;
taken in conjunction with observations of the dip ; by occasion-
ally landing and observing on the ice out of the reach of the
ship's attraction; and by exploring, as far as possible, all those
localities in which the needle may be observed to change its
direction with rapidity.

On the other hand there is reason to believe, from Major
Sabine's report to the British Association in 1837, that the
points of greatest intensity are accessible, the one lying in
somewhere about 50° S., to the south of Van Diemen's Land ;
the other in about 60° S., about midway between the meridians of
Van Diemen's Land and Cape Horn : positions named, how-
ever, rather with a view to fix our ideas as to the means of re-
search, than from supposing it possible to speak with precision
at present.

These points, it would, of course, be desirable that the vessels
of the expedition should endeavour to attain, or at least to ap-
proach sufficiently to settle their position and the amount of
the maxima of intensity.

TERRESTRIAL MAGNETISM. 37

111 order^ however, not to lose the precious opportunity offered
by the proposed expedition for placing on record the most
exact determinations in localities so remote from ordinary in-
tercourse by simultaneous observations, in correspondence with
those at fixed stations, the expedition ought to be supplied with
all the apparatus and requisites for such observations.

The laws of magnetism, under any circumstances important
to a great maritime power, are every day acquiring additional
interest by reason of the introduction of iron vessels into navi-
gation. The practicability of employing these for long voyages
will of course entirely depend on that of obtaining a satisfac-
tory correction of the disturbing influence of the magnetism of
the vessel. This influence, as appears from the recent experi-
ments of the Astronomer Royal, Mr. Airy, on the Rainbow
steamer, of 200 horse power, is enormous, and such as to
render the loss of the ship, if hazarded at sea in a long
voyage and in bad weather, hardly so much a matter of risk
as of certainty. To get rid of this influence is a problem
of no ordinary difficulty — a difliculty enhanced by the fact
ascertained in the experiments alluded to, of its originating
in two distinct modifications of the magnetic power. The
difficulty has been overcome, however, by the eminent ma-
thematician just mentioned, and the Rainbow, which before
was brought round with much difficulty from Liverpool to
London, is now running with the same confidence in her
compasses on the part of her commander as would be the case
in an ordinary ship, the cause of error being, as would appear,
completely counteracted. It is understood that the success of
the Rainbow has not only caused several other iron vessels to
be built for the navigation of the British seas and the Baltic,
but that projects on a far more extended scale are entertained
for communication by iron steamers with the most distant
regions.

This striking instance may serve, in reply to any objection
which may possibly arise to the proposed expedition, as having
for its chief and ostensible object the promotion of merely
theoretical research. That object, it is true, is to perfect a
theory, but it is a theory, pregnant, as we see, with practical ap-
plications of the utmost importance. The correction operated
by Mr. Airy's process is complete (as he has himself shown,)
only for that particular magnetic latitude for which the adjust-
ments are made, and those nearly adjacent ; and, although he
has pointed out the course of proceeding by which it may be
hereafter extended, yet the subject is one but just broached.

38 REPORT — 1839.

and awaits its development from every new light which can be
thrown upon it, either by voyages abroad or by experiments at
home.

It would be taking a very limited view to confine the objects
of the proposed expedition to the investigation of one class of
phaenomena, however intrinsically important. In naming mag-
netic research as its paramount object, the British Association
wish to be understood not as excluding or underrating others,
but rather as marking by this emphatic selection, their sense
that its adoption would stand justified in the eyes of the scien-
tific world by this object alone. They are,* however, quite
aware how many others might, and ought to be embraced in
the project of such a voyage, which, taken collectively, would
in all probability render it as memorable and as glorious as any
of those great enterprises in the Northern Seas which figure so
conspicuously in the maritime history of this country. In a
geographical view, indeed, the discovery of land which may
exist yet unsuspected in the Southern Ocean, and the tracing
out more perfectly such as has been shown to exist without
defining its extent has been considered by the geographical
members of the Association so desirable, as would have induced
them on that ground alone to have made it a subject of recom-
mendation to Government. And if we do not now dilate on
other objects, it is because we know that, supposing the expe-
dition resolved on, upon what we conceive to be its chief and
prominent ground, the other great scientific bodies of the
country, and especially the Council of the Royal Society, when
called upon, can be at no loss to indicate numerous and most
important lines of inquiry, and to furnish every necessary in-
struction for their efi'ectual prosecution.

In urging this subject on the attention of Her Majesty's
Government we wish to be understood as fully recognizing the
principle of not resorting to national assistance except where
the object aimed at is of national importance ; where private
zeal and private means are already in full activity, and exerted
to the utmost ; or where other nations have set an example
which may justly arouse our emulation. In this case too, we
may add, where no private enterprise can accomplish the end
proposed. As regards the importance of the subject, our opi-
nion is already stated of all that body of knowledge which,
taken collectively, constitutes what the French call Physique
du Globe. Terrestrial magnetism is the branch which, at the
present moment, stands nearest to the verge of exact theory.
It is an outpost ready to surrender, if attacked in form, and

TKRRKSTRIAL MAGNETISM. 39

that on which our forces ought therefore to be concentrated
with a determination to subdue it. As regards the amount of
private research ah-eady expended on the subject, and still in
activity, we may refer generally to the masses of valuable ob-
servation collected in Major Sabine's Report. For many of
these we are indebted wholly to private zeal and exertion. In
cases where the observers have been officers or persons in
public employ their services in this respect have been extra-
official and voluntary, and in some cases extremely laborious.
We may also refer to the discovery of the north-western mag-
netic pole itself by Captain Ross, in the prosecution of an en-
terprise which, however peculiar its circumstances, and how-
ever unlikely to be followed as an example by others, was yet
strictly a private undertaking. Further, we may refer to the
elaborate digests of existing knowledge contained in the varia-
tion charts of Barlow, and in Major Sabine's recent report,
drawn up at the instance of the British Association in 1837;
and lastly to the researches now carrying on (also in pursuance
of a recommendation of the British Association) by that di-
stinguished officer, in conjunction with Professor Lloyd and
Captain Ross, en the magnetism of the British Isles.

As regards the example of other nations much might indeed
be said, but we shall only cite one instance, which can call up
no ideas but the pleasing ones of admiration and gratitude, viz.
that of Norway, which, though a small and poor state, im-
posed on itself additional burthens (at a time when economy
was especially felt to be necessary), by an unanimous vote of
its Storthing, for the express purpose of defraying the expenses
of that journey of Hansteen, to which we owe his most valuable
and important magnetical determinations between the meridians
of Greenwich and Okotsk, in the north of Europe and Asia,
and from the 40th to the 75th degree of north latitude.

We therefore feel ourselves on strong ground when we call
upon Government to aid us in a task where we are actually
doing so much, and to lend a crowning hand to so much exer-
tion. Great physical theories, with their trains of practical
consequences, are preeminently national objects, whether for
glory or for utility. The peace which now happily subsists
may not continue many years longer, and in the turmoil of war
such objects are little likely to engage attention. The oppor-
tunity therefore which now exists for such an expedition may,
in the concurrence of events, be snatched from us altogether,
whereas at present everything is favourable.

{Sigtted on the part of the Comtnitteef)

J. F. W. Herschbl.

40 REPORT — 1839.

On the 29th of November the Committee again waited, by ap-
pointment, on Lord Melbourne, and the Chancellor of the
Excheouer being now present, the nature and extent of the
equipments of the fixed observatories, and of the scientific de-
partment of the proposed naval expedition, were more particu-
larly entered into, reference being made for the general views
and principles of the project to the memorial above copied, and
a further memorandum was handed in, stating more expressly
the instrumental and other requisites for the undertaking, and
an estimate, founded on the best judgment the Committee
were at that time enabled to form, of the probable expense of
the fixed observatories, which they M'ere led to rate at about
2000/. for each observatory, exclusive of chronometers and tran-
sit instruments.

To the representations of your Committee on this occasion
every attention was paid ; nor did they experience any diffi-
culty in the way of stating their views in the fullest and
amplest manner, in a less formal and official mode, either to
these or other members of Her Majesty's Government, and in
particular to Earl Minto, to whom it was especially requisite
that the views of the Association relative to the naval expedi-
tion should be clearly developed. To these various representa-
tions, for a considerable time, no definite reply was received.
Meanwhile the President and Council of the Royal Society, no
less impressed than this Association with the great importance
of the subject, had deputed a Committee of their own body for
the purpose of making a similar application. And your Com-
mittee have great satisfaction in being enabled to state, that,
aided by the warm and zealous exertions of the Marquis of
Northampton, who, whether in the chair of the last mentioned
illustrious body, or of this Association, has on all occasions
shown himself active in promoting every great scientific object, —
these concurrent representations have been attended with their
full effect^ that every point suggested in the resolutions on
which this report is founded has been ordered to be carried
out into full execution, and every observation recommended
provided for by Her Majesty's Government in the most
ample and liberal manner. And that, probably at the very
time when this report will be read to the Association, two
ships, the Erebus and Terror, will be already on their voyage
to the Antarctic Seas, under the command of Captain James
Clark Ross, carrying with them every instrument requisite for
the complete and effectual prosecution of these important re-
searches, and having on board the complete establishments,
both personal and instrumental, of the fixed magnetic observa-

TERRESTRIAL MAGNETISM. 41

tories at St. Helena, the Cape of Good Hope, and Van Die-
men's Land ; the two former being under the respective direc-
tion of Lieutenants Riddell, Lefroy and Wihnot, of the Royal
Artillery ; the latter it is contemplated to place under the direc-
tion of one of the naval officers attached to the expedition, vi^ho
will be left in charge of it.

The observatory at Montreal, in Canada, will be placed under
the direction of Lieutenant Riddell of the Royal Artillery, who
will proceed immediately to his station*.

As regards the proposed observatory at Ceylon, it has ap-
peared to your Committee, on mature consideration, that
Madras will be in many respects a preferable point, and they
therefore have not insisted on Ceylon in their representations
to Government, it being understood by them to be the intention
of the Royal Society to recommend to the Honourable Court of
Directors of the East India Company^ to order the establish-
ment of observatories in every respect similar, at that and two
other stations in British India. This recommendation, your
Committee understand, has been accordingly made, and at
once acceded to in the most liberal manner, and the instru-
ments immediately ordered ; while Major Jervis, the provisional
Surveyor-General of India, has recently visited Dublin for the
purpose of familiarizing himself with the practical details and
manipulations of the observations and instruments as adopted
in the magnetical observatory of Dublin. Messrs. Riddell,
Wilmot, and Lefroy, have also availed themselves of the same
opportunity ; and, by the subsequent erection at Woolwich of
a set of the magnetic instruments, every facility has been af-
forded to the officers of the naval expedition for becoming ac-
quainted with the processes.

The staff of each observatory will consist of the officer in
charge, three non-commissioned officers, and two gunners, by
which it is expected that the observations will be continued
throughout the 24 hours ; i. e. at every second hour throughout
the day and night.

Each observatory is supplied with a very complete set of me-
teorological instruments, by which not only will the requisite
data be afforded for the due correction and reduction of the
magnetic observations, and for tracing the influence, if any, of
meteorological changes on the magnetic elements, but a most
valuable and complete series of meteorological observations will
be procured at every station, made with compared instruments,
and on a perfectly uniform system.

* Montreal has been subsequent!}' cbaiiged for Toronto.

42 REPORT— 1839.

The naval expedition will be supplied with every instrument
in duplicate in case of accident in the course of along and diffi-
cult voyage, and to provide also for the contingency of the ships
temporarily parting company.

Thus everything appears arranged so as to afford all human
security for the attainment of the objects proposed in the most
complete and satisfactory manner. And while your Committee
feel themselves bound to acknowledge in strong terms the
ample and liberal manner in which, on this important occasion,
every demand on the national resources, without a single ex-
ception, has been granted, they consider it no less their duty
to express their hopes that this splendid example will be fol-
lowed up by other nations, and that this operation will thus
become not merely a British, but an European and American
one : that, in short, the opportunity thus afforded for com-
bined and simultaneous exertion (such as the history of science
has never yet offered) will be taken advantage of by observers,
both public and private, in every region of the globe. The
theory of terrestrial magnetism will thus at once be placed on a
broad and ample basis of carefully observed facts, and the re-
cords of the next three years will be appealed to in every future
stage of the progress of that science as its legitimate point of
departure, in the new era which is opening for it.

Finally, as respects the application of the grant of 400/.
made by this Association for the purchase of instruments, your
Committee have to report that no part thereof has been ex-
pended, and they consider that none will be needed, as Govern-
ment has charged itself with the entire expense of the instru-
ments for the expedition, and for the observatories, under the
direction of its own officers ; and the Board of Directors of the
East India Company have undertaken, with their usual liberality,
their own observations at their own cost. The grant, however,
has proved of most effectual service, as it has enabled your
Committee, in more than one instance, to order instruments in
the absence or in anticipation of distinct official authority to do
so, and thereby to save much precious time, which, on the pre-
sent occasion, has been hardly less valuable than money.

(Signed) J. F. W. Herschel.
H. Lloyd.

Report on Briiish Fossil Reptiles. By Richard Owen, Esq.,
F.R.S. F.G.S. &c. &c.

1. IhE British fossil organic remains referrible to the class
Reptilia of Cuvier, if they do not indicate more numerous
and diversified generic and specific forms, unquestionably ex-
hibit more singular modifications of the typical structure of
their class than do those belonging to any other primary group
of the vertebrate division of animals.

The review which I have taken of the Saurian remains alone,
which are treasured in different collections, has convinced me
that they yield only to the Ichthyolites in the number of extinct
species which they represent. And when it is remembered how
large a proportion of the fossil fishes, described and figured in
the classical work of M. Agassiz, includes species which are
characteristic of the strata of Great Britain, it may be conceived
that a report on our extinct reptiles could not be satisfactorily
completed by me without the devotion of the leisure hours of
more than a single year, nor be recorded in a brief space.

However captivathig to the comparative anatomist such a
subject must be from the rare and most singular condi-
tions of organic structure manifested in the remains of these
extinct and often highly developed cold-blooded animals, or
however interesting from the important physiological relations
traceable between their structural modifications and the condi-
tions under which they ones existed, and the parts assigned to
them in the theatre of an ancient world, — nevertheless, I could
not have ventured to have proposed to myself the ' British
Fossil Reptilia' as a subject of continuous and systematic
research, without the aid and encouragement which the British
Association has liberally granted to me for that purpose.

Aware that the proposed report was not to be limited to a
review of the actual state of the Reptilian branch of Palaeonto-
logy, — a comparatively easy task, — but to embrace an account,
founded, as far as might be, on actual observation, of those
reptilian remains that have been hitherto discovered in differ-
ent geological formations of the British Islands, I determined
to divide the subject according to the natural families of the

44 REPORT — 1839.

class, and have selected the Enaliosauria, or ^ Lizards of the Sea'
— a race of which there is no longer any existing representative
— for the subject of the present inquiry.

For the study of these remains I have visited the museums
of the metropolis, of Cambridge, Birmingham, Bristol, Bath,
Hull, York, Newcastle, Liverpool, Manchester, Lancaster, and
other places, and have had access to the private collections of
Viscount Cole, Sir P. Grey Egerton, Sir Astley Cooper, Dr.
Johnson, Messrs. Hawkins, Bowerbank, Saull, T. Bell, and
other gentlemen ; to whom, as well as to the scientific curators
of the public and provincial museums above cited, I beg to re-
turn my grateful acknowledgements for the liberal exposition
of their fossil treasures, and their urbane attentions to every
wish that arose out of my occupations.

As the comparison of the Saurian remains in these collections
with those described or indicated in the recent treatises of Prof.
Ja'ger, M. Hermann von Meyer, and other distinguished German
Palaeontologists, could not in all cases be made with satisfactory
precision from the descriptions alone, I found it necessary to
visit some of the principal depositories of the original specimens
studied by those authors. At Frankfurt, besides the liberal
access to the Senkenbergian museum, I enjoyed the privilege of
examining the private collection and the valuable and extensive
series of original drawings of fossils made by M. Hermann von
Meyer, to whom I am particularly indebted for his attentions.
I have much pleasure in making similar acknowledgements to
Prof. Jager of Stuttgard, and to Prof. Kaup of Darmstadt, the
peculiar treasures of whose collection, however, belong to a
higher class of Vertebrata.

The study of these collections has enabled me to identify
some of the Saurians of the German lias beds with the species
characterizing the corresponding strata in our own island, and,
on the other hand, to obtain a certainty as to specific differences,
which, without actual comparison, would have been only matter
of conjecture.

Of the reptilian species, the fossil remains of which are the
subject of the present report, the term of existence has long
expired; and the peculiar roodifications which characterized
their type of structure, can now be studied only in the remains
which the labours of the geologist bring to light. They will be
here considered under three points of view, anatomically, zoo-
logically and geologically : or, first, with reference to the re-
storation of the skeleton and the homology of its several parts
to those of existing Vertebrates ; secondly, as to the generic and
specific modifications of the Enaliosaurian type, and the affini-

BRITISH FOSSIL REPTILES. 45

ties of the species ; thirdly, with relation to the localities and
extent of strata through which the several species are distri-
buted, or to which they may be restricted.

Part 1. Enaliosauria. — General Characters of the Order.

The Enaliusaurs were vertebrate, air-breathing and cold-
blooded animals; referrible therefore to the great class of Rep-
tilia in the Cuvierian system ; and indicative of a primary
modification of the typical structure of that class, by which
they were fitted more especially for a marine life.

The proof that the Enaliosaiirs respired atmospheric air im-
mediately is afforded by the position and structure of the nasal
passages, and by the osseous mechanism of the thoracic- abdo-
minal cavity.

The evidence that they were cold-blooded animals, reposes
on the unanchylosed condition of the elementary osseous pieces
of the occiput and other cranial bones, of the lower jaw, and
of the vertebral column : the laws of organic coexistence
justify the conclusions from these conditions of the osseous
system that the heart was adapted to transmit only a part of
the circulating blood through the respiratory organs.

The peculiar modifications of the saurian type-, or the special
Enaliosaurian characteristics, consist in the absence of the ball
and socket articulations of the bodies of the vertebrae ; the
position of the nostrils at or near the summit of the head ;
their separated hsemapophyses ; the numerous, short, and flat
digital bones, which must have been enveloped in a simple, un-
divided, tegumentary sheath, forming in both the fore and hind
extremities a fin resembling in external appearance the paddles
of the Cetacea.

Other genera of Fossil Saiiria were aquatic and marine, and
consequently possessed extremities modified for swimming, as
are indeed those of the marine Chelonia of the present day, and
in a less striking degree the feet of the Crocodiles among exist-
ing Sauria. But those reptiles only ought to be regarded as true
Enaliosaurs which combine limbs fitted for swimming with the
cranial and vertebral characters above defined*.

The Enaliosauria offer two principal modifications of their
anatomical structure, of which the genera Plesiosaiirus and

* The saurian system of M. H. v. Meyer, which includes the Teleosaurs and
Mososam-s, with the true Enaliosaurs, on account of the modifications of the
locomotive extremities, is not attended with any advantages compensatory of
its extremely artificial nature. The bones of the extremities are less available
than the vertebra? or teeth in indicating the generic and specific characters, or
the true affinities of the individual Saurian to which they may have belonged.

46 REPORT — 1839.

Ichthyosaurus are the types ; and I next proceed to consider the
general characters of these two primary divisions of the order.

These characters are mainly derived from modifications of
the vertebral column, as well with regard to the form and confi-
guration of the individual bones, as to the relative propor-
tion of the different groups of vertebrae called cervical, dorsal,
caudal, &c. The vertebrae also frequently afford the best
characters for the distinction of species, as well as of genera ;
and as they are the parts of the skeleton most commonly
discovered in the strata characterized by the Enaliosam-ian
remains, they have received especial attention in the present
Report.

To save much repetition, otherwise unavoidable in the subse-
quent pages, and to facilitate the comprehension of many of
the descriptive details, it will be advantageous to premise some
observations on vertebrae in general, before entering upon the
modifications of these bones which characterize the Plesiosauri
and Ichthyosauri respectively.

At the commencement of my examination of the fossil re-
mains of the Enaliosaurians, I endeavoured to apply to the
parts of the vertebrae, which in these animals are frequently
complicated, and with the elements more or less dislocated, the
views and nomenclature of M. Geoffroy St. Hilaire, whose ana-
lysis of a vertebra in the abstract has been generally adopted in
this country. I was soon compelled, however, to relinquish
the advantage which the vertebral theory of that philosophical
anatomist seemed to promise ; finding that it did not agree with
my observations either on the cartilaginous or osseous centres
as they appear in the development of a vertebra in the embryo ;
or on the fully- developed elements as they are exhibited in dif-
ferent classes of the vertebrate series, more especially in certain
parts of the vertebral column of the Plesiosaiirus.

I need hardly observe that a vertebra may be traced through
its various degrees of complication, either during the progressive
stages of its development, or by taking permanently-formed
vertebrae of different grades of complexity in different animals ;
or, in many instances, by comparing the vertebrae in different
parts of the spine in the same animal.

The terminal vertebrae of the tail in most species exhibit the
simplest condition of these bones. The most complicated ver-
tebrae which 1 have yet met with, are those at the lower part
of the neck of certain birds, as the Pelican ; or at the beginning
of the tail of a Python, or other large serpent.

The parts or processes of such a vertebra maybe divided into
autogenous^ or those which are independently developed in

BRITISH FOSSIL REPTILES. 47

separate cartilages, and exogenous, or those which shoot out as
continuations from these independent constituents. The auto-
genous, or true elements, are,

1st. The centrum, or body of the vertebra, which, in Mam-
malia, as Cuvier has observed, is complicated by two epiphyses.

2nd. Two superior laminae developed to protect the great
nervous cord which rests on the upper surface of the centrum,
and which I have therefore proposed to call neurapojjiiyses*.

3rd. Two inferior laminae developed, generally to protect the
great blood-vessels on the under surface of the centrum, and
which I have proposed to call hcemapophyses \.

4th. The superior process :|: which is connected and generally
anchylosed with the distal extremities of the neurapophyses,
and forms, in conjunction with those processes, the superior
arch of the vertebra.

5th. An inferior spinous process, which is connected, and
commonly anchylosed with, the distal extremities of the hmma-
pophyseSy forming, in conjunction with these, a chevron or
V-shaped bone.

To the category of autogenous vertebral pieces belong the ribs,
which generally are anchylosed to the other vertebral elements
in the cervical, sacral, and caudal vertebrae of the warm-blooded
vertebrate classes.

The propriety of regarding the ribs as vertebral elements is
well illustrated, in the Plesiosaurus, in the cervical, sacral, and
caudal vertebrae of which they have been generally described
as transverse processes, although they are separate bones.

These elements bear the same relation to the centrum and its
true transverse processes which the spinous processes do to the

* They are \\\e periaux, oi perivertebral elements, of GeofFroy St. Hilaire.

f These are the clievrou-hones of Mr. Conybeare, the paraanx or paraverte-
bral elements, of GeofFroy St. Hilaire ; terms which he also applies to the costal
processes, regarding these in the abdominal and thoracic regions as the ex-
panded halves of the chevron-bones. If I had adopted GeofFroy 's term, ' paraal,'
or its English equivalent, ' paravertebral element,' I must have diverted it from
its original sense, in which it is applicable to two distinct elements, viz. the ribs
and chevron-bones, which will be seen to co-exist in certain vertebrae of the
Enaliosauri, and some existing animals ; and I have preferred, therefore, to
invent and define a new term, which has the advantage of expressing a physio-
logical relation ; and I am happy in being able to cite the authority of Cuvier
for the propriety of this step. Flis words are, in reference to an analogous
case, " Donner a un mot connu im sens nouveau est toujours un precede dan-
gei'eux, et, si Ton avait besoin d'exprimer une idee nouvelle, il voudrait mieux
inventer un nouveau terme, que d'en detourner ainsi un ancien." Mem. du
Mus., tome ix. p. 1 23.

X This is regarded by GeofFroy, but without due grounds, to consist essen-
tially of two lateral moieties, termed, epiaux ov epii^ertcbral tiementB.

48 REPORT— 1839.

neurapopliyses and haemapophyses, but they are more rarely
aiichylosed at their central or proxmial extremities.

The length which the ribs sometimes attain need form no ob-
jection to their being regarded as parts of a vertebra, when it is
remembered that the spinous processes, both above and below in
some fishes, are longer than the longest ribs in the same skeleton.
In the system of M. Geoffroy St. Hilaire, the nine elements of
a vertebra are completed by reckoning the spines of the dermal
skeleton, which in fishes are intercalated or articulated with
the neural and haemal spines of the true endo-skeleton as essen-
tial elements of a vertebra; and the paraaiix, or ha^majjophi/ses,
are described as being developed in length and changed in direc-
tion, in order to form the vertebral ribs of the thoracic and ab-
dominal regions.

The vertebrae of the Bird and Ophidian already alluded to,
prove that vertebral ribs and inferior laminae or haemapophyses
may co-exist ; and the composition of the spine of the Plesio-
saurus, especially in the caudal region, well illustrates this fact :
for the costal appendages, which are generally anchylosed to the
other vertebral elements, in the cervical, sacral, and caudal re-
gions of the spine of the warm-blooded vertebrate classes, retain
their original separate condition throughout the vertebral column
in the Plesiosaur, and pass by such imperceptible gradations
from one condition of physiological subserviency to another,
that their nature cannot be mistaken when the entire series is
studied in a complete skeleton ; although, when seen in detached
vertebrae of the neck or tail, they present the appearance, and
have been generally described as, hatchet-bones, or transverse
processes.

True transverse processes are, however, always exogenous, or
mere projections from the centrum or the neurapophyses, and
are of secondary importance. They are of tv/o kinds, superior
and inferior ; both are present in the cervical vertebrae in most
classes of the vertebrated animals ; the inferior transverse pro-
cesses alone are developed in fishes.

The oblique, or articulating processes, are also exogenous,
and may be developed either from the neurapophyses, or the
base of the superior spines of the vertebrae.

As in other complicated bones resulting from an association
of several osseous pieces, certain elements of a vertebra may be
modified in position and proportions, so as to perform the ordi-
nary functions of others M^hich may be atrophied or absent :
thus in fishes, the inferior transverse processes are gradually
bent downwards, until, in the dorsal region, their extremities
meet and perform the functions of the haemapophyses;

BRITISH FOSSIL REPTILES. 49

The costal processes or ribs are considered by Geoffroy St.
Hilaire* to undergo in the Cetacea a similar change of direction,
and also a dislocation from their usual attachments, and to have
their distal extremities bent downwards and anchylosed to a
rudimental spine, so as to assume the form and perform the
offices of chevron-bones, or hsemapophyses ; but as the horizon-
tal processes of the caudal vertebrae in the Cetacea (as exempli-
fied in the skeleton of a young Balaam untarctica, fourteen
feet in length, which I have lately had the opportunity of ex-
amining,) are originally developed from distinct centres, and in
distinct cartilages, they appear to me to represent, with the
corresponding separate vertebral elements in the Plesiosaurs,
the true costal appendages of the tail, and the hsemapophyses
must therefore be regarded as other and different elements of
the vertebra. This view is supported by the fact that the long
transverse processes supporting the ribs in the thoracic region of
the spine in the same young whale, have no osseous nuclei de-
veloped in them, but are continuous cartilages from the still
unossified parts of the centrum. I may observe also that the
haemapophyses in the young Cetaceans examined by me, exhibit
what appear to be their permanent condition in the Enaliosau-
rians, viz. a want of bony union at their distal extremities ; at
least I have never yet observed a true chevron-shaped bone,
such as results from the anchylosis alluded to, in any skeleton
of an Enaliosaurian.

Of the vertebral elements above enumerated the centrum is
the most constant in its existence, but the neurapophyses and
their spines are the most constant in regard to ossification : and
there is an obvious reason, in the importance of the nervous
cord which they are destined to protect, why these parts should
be firm and resisting when circumstances might forbid the con-
solidation of the other vertebral elements. Thus, the neurapo-
physes are cartilaginous in the Lampreys, or P ctromy zontida; y
while the centrum is gelatinous. The neurapophyses and their
spines are completely ossified in the Lepidosiren,while the bodies
of the vertebrae are represented by a fibro-gelatinous cord. A
similar condition appears to have obtained in the fossil Micro-
donts and some other osseous fishes, in which the ossified neur-
apophyses and hasmapophyses have been preserved, while no
trace of the bodies of the vertebrae remains.

CHARACTERS OK THE GENUS PLESIOSAURUS.

I now proceed to apply the foregoing views of the elementary
parts of a vertebra, in the first place, to the exposition of the
* Mi'm. dir Museum, ix. p. 1 1.?.

VOL. VIII. 1839. K

50 REPORT— 1839.

generic characters of the vertebral column in the Plesio-
sauri.

The most conspicuous and remarkable feature of this part
of the skeleton, is the extraordinary length of its cervical portion,
which includes from twenty to forty vertebrae. The articular
surfaces of the bodies of the vertebrae are either flat or slightly
concave, or most frequently convex in the centre and concave
at the periphery. In general the bodies present two pits at
their under part, but this character is not constant.

The cervical vertebrae of the Plesiosauri generally present the
following parts in a separate or unanchylosed state, — the
centrum, the neurapophyses, and ribs ; and it is interesting to
observe that although, in general, no transverse processes are
developed in this region, an analogy with the structure charac-
teristic of this part of the spine in the Crocodile is maintained
in the division of the articular surface for the cervical rib into
an upper and lower portion by a horizontal fissure ; which
structure is well described and figured by Mr. Conybeare in
the Plesiosaurus dolichodeirus.

In Mammalia, the interspace of the two cervical transverse
processes on each side is occupied by the vertebral artery : in
Birds, by the vertebral artery and sympathetic nerve : in the
Plesiosaurus it is too inconsiderable to lead us to imagine it to
have been subservient to the protection of any important vessel
or nerve, but its existence, besides being referrible to the law of
adherence to type, may also have had relation to tiie presence
of an interarticular ligament for the purpose of connecting the
head of the cervical rib or hatchet-bone to the body.

As the cervical vertebrae in the genus Plesiosaurus approach
the dorsal, the inferior part of the costal articulation becomes
smaller, and a corresponding increase of surface is afforded by
the superior facet, which also gradually rises from the centrum
to the neurapophyses, and in the dorsal vertebrae stands boldly
out as a true transverse process from the upper side of the base
of each neurapophysis.

At the sacral vertebras, however, the transverse processes
subside to the level of the neurapophyses ; and as the caudal
vertebrae recede from the trunk, the articular surface, which, as
in the neck, represents, or is in the situation of, the transverse
process, gradually descends, and passes from the neurapophysis
to the side of the centrum ; but it is not divided by the longitu-
dinal groove which characterizes the costal surface in the neck.

This groove is more marked in some than in other species of
Plesiosaurus ; and I have seen Plesiosaurian vertebrae undoubt-
edly cervical, in which no trace of it was visible.

The neurapophyses are commonly unanchylosed with the ver-

BRfTISH FOSSIL REPTILES. 51

tebral centres in any part of the spine, and in some instances
throughout the cervical, and at the anterior part of the dorsal
region, the neurapophyses have appeared to be joined each by
an articular surface to the spine above, as they are to the cen-
trum below, — the spines here remaining apparently throughout
life unanchylosed to the neurapophyses. This condition of the
upper vertebral elements is rarely seen in any cold-blooded
vertebrate, and never in the warm-blooded classes.

In those parts of the spine where the vertebrae enjoyed less
mobility upon each other than in the neck, the spines become
anchylosed to the neurapophyses at an earlier period.

The hsemapophyses co-exist with the ribs or paravertebral
elements in the caudal region of the spine, but they continue
throughout life to be unattached by bone either to the centrum
above or to each other below ; and here also their spine is not
developed, and consequently no true chevron-bone is formed in
the Plesiosauri. The heemapophyses are also continued along
the inferior surface of great part of the abdomen, forming there
the sternal or abdominal ribs ; and just as the neurapophyses
are developed in the transverse direction to protect the expanded
cerebral masses in the cranial region, so here the hsemapophyses
are in like manner elongated transversely, and their spine is in-
troduced and modified to form a third mesial rib-like bar, con-
necting, however, as usual, the lower or distal extremities of
the h8emapophyses_, and completing the osseous cincture of the
abdominal viscera.

The tail in the Plesiosauri is relatively much shorter than
in the Ichthyosauri, and there is an obvious reason for the
curtailment of this part of the animal; for in the Plesiosauri,
the length and mobility of the neck renders a special develop-
ment of the tail for producing the lateral movements of the
head unnecessary.

The bodies of the vertebrae, in most species of Plesiosaurus,
are traversed vertically by two vascular canals, which lead from
the medullary or spinal canal to the inferior surface of the cen-
trum, where they terminate each by an orifice, and sometimes
by two orifices, on each side the middle line. These orifices
are not, however, a constant character of the genus Plesiosaurus,
neither are they peculiar to this genus, being present in the ver-
tebrae of the Cetacea, as well as in those of other Sauria.

In a section of the vertebral centrum of a Plesiosaurus, the
osseous texture for some lines near the anterior and poste-
rior articular surfaces is denser than in the rest of the vertebrae,
and the direction of the laminae and fibres is vertical : in the
intermediate portion the laminae are horizontal.

E 2

52 REPORT— 1839.

The head of the Plesiosauri resembles that of the Crocodiles
in its general form, but is relatively much smaller in proportion
to the body : the elongated form of the strong and prominent
cranial bones, most of which extend from point to point, with
wide interspaces like the timbers of a scaffolding, forms one of
the first indications of a deviation from the Crocodilian type,
and of the affinity of the Plesiosaurus to the Lacertian Sauria ;
and this affinity is further exemplified in the condition of many
of the individual bones.

The occipital bone includes the basilar, lateral or ex-occipital
aiid supra-occipital pieces in a permanently separated condition,
as in other Reptiles. The basi-occipital forms a larger propor-
tion of the articular tubercle for the atlas, and the ex-occipitals
a less proportion, than in the Crocodiles ; and the circumfe-
rence of the foramen magnum is completed by the supra-
occipital element ; in both which respects the Plesiosaurus
manifests its affinity with the Lacertian Sauria.

The mastoid elements extend from the occipital to the tym-
panic bones ; but above these and between the occiput and the
strong arched pedicle supporting the lower jaw there is a vacuity
leading from the occipital region into the temporal fossae. The
corresponding openings in the skull of the Crocodiles are re-
duced to very small size in consequence of the expanded form
and oblique position of the tympanic bone, but in the Lacertian
Sauria they are as wide as, if not wider than, in the Plesiosaurus.

The parietal is a strong triradiate bone in the Plesiosaurus,
consisting of a median piece corresponding with the normal
parietal in the Crocodiles, and of two transverse elongated pro-
cesses, formed, as it were, by a bifurcation of the posterior part
of the median piece.

In a young specimen of Plesiosaurus macrocephalus in the
collection of Viscount Cole, the median or sagittal suture dividing
the two parietals is still distinct : in older specimens of the PI.
Hawkinsii I have always found it obliterated, so as to justify
the above description of the parietal as a single triradiate bone.

The median portion of the parietal offers two modifications of
structure Avhich point out in a striking manner the deviation of
the Plesiosaurus from the Crocodilian, and its approximation
to the Lacertian type of the Saurian structure.

The first of these characters is the median crest or ridge
from which the surface slopes away on each side ; proving that
the temporal muscles were relatively as strongly developed as
in the Iguance, e. g., and were only separated from one another
at the top of the head by the intermuscular ridge. In the Cro-
codiles on the contrary, in which the ponderous jaws are worked

BRITISH FOSSIL REITILKS. 53

principally by the masseteric and pterygoid muscles, the tempo-
rals are small, and are separated from each other by a flattened
space occupying nearly the whole of the simple parietal bone.

The second character of the median part of the parietal, which
brings the Plesiosaurus near to the Lizard tribe, is a moderate-
sized elliptical vertical perforation of the bone, a few lines be-
hind the coronal suture, which perforation is analogous to that
described by the Rev. Lansdowne Guilding in the Iguana
under the name of the Foramen Homianum, where, however,
it is situated directly upon the coronal suture, in the situation
of the anterior font ane lie. The same foramen, however, exists
in many other genera of Lacertian Sauria ; and in Mo7iitor, La-
certa proper, &c. it is situated, as in the Plesiosaurus, entirely
in the parietal bone. There is no trace of this foramen in th.e
Crocodilian Sauria. The posterior bifurcation of the parietal
bone forms a third instance of the resemblance of the Plesio-
saurus with the Lacertian, and its difference from the Croco-
dilian structure. These processes are of considerable strength,
and commonly form the most prominent parts of the cranium in
fossil specimens : they articulate by means of an oblique sigmoid
suture with the tympanic bone*.

Frontal. — The frontal bone consists of a median, two anterior
and two posterior pieces. The median frontals extend as far
forwards as the midspace between the small nostrils, and appear
to terminate in a point between the commencement of the narrow
nasal bones. The interfrontal suture in the young PL rnacro-
cephalus before alluded to, is elevated by a ridge continued for-
wards from the parietal crest. The outer margin of the median
frontal forms the superior boundary of the orbit. The anterior
frontal enters into the formation of the anterior and superior
angle of the orbit, and is wedged in between the mid-frontal
and superior maxillary bones. The posterior frontal bounds
tiie orbit posteriori}^, and extends downwards to join the malar
bone, like the columnar portion of the post-frontal bone in the
Crocodiles ; but it is broader and more superficially situated in
the Plesiosaurus, and thus resembles more the corresponding
part of the cranial structure in the Lacertian Sauria. The pos-
terior frontal differs further and in a more striking degree from
the Crocodilian type in not being extended backwards to join the*
mastoid ; so that the skull of the Plesiosaurus does not present,

* One of Miss Philpott's specimens exhibits the parietal of a PI. doVicJioJeirns
thinned oft' posteriorly, and rugous, apparently forming an articulating or sutu-
ral surface for the overlapping of the tympanic bone.

In most specimens the sagittal suture, dividing the median parietals, is per-
sistent.

54 REPORT — 1839.

as in the Crocodiles, an osseous ridge traversing longitudinally
the temporal fossa, like a second zygoma, and dividing it into
an upper and a lower cavity.

Zygomatic. — The zygomatic element of the temporal bone,
instead of being extended obliquely, parallel with, and joined to
the tympanic bone, stretches horizontally from the malar and
post-frontal backwards to the lower end of the tympanic, and
is attached, as in the Lacertian Sauria, only by its two ex-
tremities.

Tympanic. — The tympanic bone in its general form, and
especially its length, is intermediate to the Crocodilian and La-
certian types, but exceeds them both in its robustness.

Facial bones. — When we come to examine the bones of the
face, the resemblance to the Lacertian Saiiria begins to dimi-
nish, and that to the Crocodiles to increase. This tendency to
the higher types of Saurian organization is shown in the strength
of the whole maxillary apparatus, in the great relative size of
the intermaxillaries, the rugged exterior surface of the bones,
and above all in the distinct alveolar cavities for the teeth.

The external nostrils, however, form a striking exception to
this tendency ; and their size and position, combined with the
structure of the paddles, indicate the analogy of the extinct
Enaliosaurs to the existing Cetaceans, and offer a beautiful
example of the adaptation of structure to the peculiar exigencies
of a species.

The apertures through which the air is respired are situated
a little anterior to the orbits near the highest part of the head.
In the Crocodiles they are situated, as is v/ell knov/n, near the
anterior extremity of the snovit, are blended together into a
single aperture, and nearly the whole of their circumference is
formed by the intermaxillary bones. In the Plesiosaurus the
intermaxillaries form an extremely small part of the boundary
of the nasal apertures, which chiefly consist on each side of an
interspace at the convergence of the anterior frontal, nasal, and
superior maxillary bones ; the nostrils are also separated from
each other by the nasal bones, as in the Lacertian Sauria.

The intermaxillary suture extends from the anterior part of
the nostrils forwards to a little more than halfway between the
orbit and the anterior extremity of the cranium. One of the
strongest of the inferior teeth usually rises just in front of this
suture, and a slight notch at that part seems to correspond
with that tooth, presenting a resemblance to a very character-
istic structuse in the true Crocodiles.

The lachrymal bone forms a great proportion of the anterior
part of the orbit : the superior maxillary enters next into the

BRITISH FOSSIL REPTILES. 55

formation of the circumference of the orbit below the lachrymal ;
and the malar bone rests by an oblique suture upon its posterior
extremity. The posterior margin of the malar bone is joined to
the posterior frontal as well as to the zygomatic bone, and thus
completes the osseous boundary of the orbit posteriorly.

Lower jaw. — The lower jaw of the Plesiosaur presents the
complicated structure usual in the Saurian order. The dentary
piece appears soon to become anchylosed to its fellow at the
symphysis, and is chiefly remarkable for the expansion of its
anterior extremity. The angular and surangular pieces are not
separated by an intervening vacuity as in the Crocodiles, but
are joined together throughout as in the Lacertian group. The
surangular rises higher and forms a sharper edge for the inser-
tion of the temporal muscles than in the Crocodiles, a structure
which agrees with the greater development of these muscles, as
indicated by the size of the temporal fossae. The articular piece
presents a regular and deep concavity for the reception of the
articular end of the tympanic bone : it is, as Mr. Conybeare has
well remarked*, more developed than in the Crocodile, and thus
approximates more nearly to the corresponding part in the La-
certian type. The angular piece is prolonged backwards beyond
the joint, but not quite to the same extent as in the Crocodiles.

Sterno-costal arcs. — The ordinary or vertebral ribs have been
already spoken of as essential parts or appendages of a vertebra :
their free extremities are connected together, in the abdominal
region, by a series of intermediate slender elongated pieces,
termed by Mr. Conybeare the 'sterno-costal arcs.' Each arc
includes, in the Plesiosanrus, seven pieces : the median one is
transversely elongated, slightly bent, and pointed at both ex-
tremities ; the lateral pieces have a similar form, except that the
extremity of the outermost, which joins the vertebral rib, is
obtuse : each piece as it recedes from the median line overlaps
the anterior part of the one which it succeeds, where it is
adapted to an oblique groove. This kind of joint probably
admitted of a yielding or sliding motion of the pieces one upon
the other, and favoured, as Dr. Buckland has observed, con-
siderable expansion of the cavity containing the lungs.

Pectoral arch. — Of the bones composing the pectoral arch
the broad coracoids are the most conspicuous on account of their
remarkable expanse in the antero-posterior direction ; their in-
ternal and anterior margins are gently convex, and meet at the
mesial plane, where they overlap the anterior thoracic ribs.
The ento-sternal piece is wedged into their anterior interspace ;

* Geol. Trans., 1822, p. 121.

56 REPOur— 1839.

it consists of a short mesial process, and two broad lateral ex-
pansions.

A strong triradiate bone, which seems to represent, as in the
Chelo7iia, the scapula and clavicle united, arches from the outer
extremity of the ento-sternal branch to the corresponding ex-
tremity of the coracoids, with which it combines to form the
shoulder-joint, and near which point it sends upwards and
obliquely backwards a branch or process representing the true
scapula.

Pectoral extremity . — The humerus is a stout and moderately
long bone, rounded at its proximal extremity, and flattened as it
approaches the elbow-joint : it is curved slightly backwards.

The radius and ulna are both short and flat bones, but rela-
tively longer and more distinctly marked than in the Ichthyo-
sauri : the radius or anterior of the two bones is nearly straight ;
the ulna is curved, with its concavity directed towards the radius.

The carpus is very distinctly defined, consisting of a double
row of small flat rounded ossicles, from six to eight in number.
The metacarpal bones, five in number, are elongated, slender,
flattened, and slightly bent. The digits never exceed the num-
ber of the metacarpal bones, but consist generally of more than
the usual number of phalanges. The first, or radial one, cor-
responding with the thumb, has generally 3, the second 6 or 7?
the third 8 or 9, the fourth 8, and the fifth 6 phalanges. These
bones are moderately long and slender, but gradually taper to-
wards the distal end of the digits : they are joined together in
each digit by flattened surfaces, indicative of a mere yielding
movement on one another. There can be little doubt that they
were enveloped, like the paddles of the Cetacea, in a common
sheath of integument. From the natural curve of the digits,
the paddles of the Plesiosaur nmst have had a more elegant and
tapering form, and have possessed greater flexibility, than those
of the modern Cetacea.

Pelvic arch. — The hinder or pelvic extremities almost always
equal, and sometimes, as in PI. macrocephalas, exceed the an-
terior ones in size.

The pelvic arch consists of a short and strong ilium, and a
broad pubis and ischium, both of which are expanded in the
antero-posterior direction, analogously to the coracoids in the
pectoral arch.

Pelvic extremity. — The radiated appendages of the pelvic
arch so closely correspond with those of the pectoral arch as to
require little to be said respecting them. In the modifications
of the two bones of the leg, tlie posterior one, or fibula, corre-
sponds in its curved form with the ulna, and illustrates an

BIUTISll FOSSIL REPTILES. a/

analogy which is indioaled in other animals. The tarsal bones
are principally remarkable for their small size on tlie tibial or
anterior side of the series, indicating that the hind paddle had
a freer inflection forwards, or npon the tibia, than in tlie opposite
direction. This structure may have given a compound motion
to the propelling stroke of the paddle, similar to that which in
skilful rowing is called ' feathering ' the oar.

The five metatarsals and their digits correspond in structure
with those of the fore paddle. The first or tibial metatarsal
supports 3 phalanges, the second 5, the third 8 or 9, the fourth
8, and the fifth G phalanges. Tlie articular extremities of the
phalanges of both the fore and hind paddles are subconcave,
with an irregular surface, indicating that they were joined by
ligaments or fibro-cartilage, and not by synovial membrane.

Plesiusaiiriis Haiu/dnsii.

Having now given a general sketch of the skeleton of the
Plesiosaurus, I proceed next to point out the modifications of
this type in the different species ; and I shall begin with that
of which the greatest number of complete or nearly complete
skeletons exist in the British Museum and other collections.

The species to which these skeletons belong is described and
figured in Mr. Hawkins's memoir on IcJithyosauri and Pleslo-
saiiri under the name oitriafarsostiims ; but as this designation
relates to an imperfect state of the tarsus in the right foot, (for
a fourth bone is present in the left tarsus of the same specimen,
and a second specimen of the same species in Mr. Hawkins's
collection exhibits five tarsal bones on each side,) I propose to
describe it under the name of Hawkins's Plesioscnw {Flvsiosau-
riis Hawkinsii) as a sincerely offered though inadequate tribute
of admiration of the indefatigable labour and rare skill witli which
its remains have been disencumbered of their earthy shroud.

The head of the PL Flawkinsii is of moderate size, smaller
in proportion than in the PL maci'ocephahts, and somewhat
larger than in the PL dolichodeimis. The neck equals three
lengths of the head, and the neck and head together equ;d the
trunk and tail. The number of vertebrae throughout the spinal
column is between 90 and 100. In the first or anterior 31
vertebrae the centrum supports the whole or part of the costal
pit : from the 32nd to the 56th vertebra inclusive the costal
articular surface is wholly impressed upon the neurapophysis :
from the 55th vertebra the costal pit begins again to descend
upon the side of the centrum, and it has entirely left the neura-
pophysis at the Gist vertebra. At the 80th vertebra the costal
processes disappear.

58 REPORT — 1839.

In consequence of the unequivocal presence of ribs through-
out so great a proportion of the vertebral column, the ordinary
characteristics of cervical, dorsal, lumbar, and caudal vertebrae
are wanting, and a definition founded on the relative size or form
of the costal elements becomes, from the gradual manner in
vi^hich they alter in these respects, very ambiguous and difficult
in its application. I have therefore proposed, in order to gain
a surer point of comparison of the different species of Plesio-
sauri, to reckon those vertebrae as cervical in which the centrum
exhibits the whole or a part of the costal articular surface. Tlie
body of a cervical may always be distinguished from that of a
caudal vertebra in being without any trace of haemapophysial
pits. The dorsal vertebrae are those in which the costal surface
is situated wholly on the neurapophysis. The caudal vertebrae
are characterized by having both costal and haemapophysial
impressions on the body, except the terminal ones, which are
readily distinguished by their small size, the absence of both the
above-named impressions, and by the concave character of the
articular surfaces of the bodies.

The cervical vertebrae present the following characters in the
species under consideration : taking the transverse diameter of
the body of the vertebra at 10, the vertical diameter of the same
is 9, and the antero-posterior 8. The articular surfaces present
the normal Plesiosaurian character, being slightly concave, with
a gentle convex rising in the centre of the concavity.

The exposed or nonarticular surfaceof these vertebras is smooth.
The costal pit is longitudinally elliptical, situated near the lower
part of the centrum in the anterior two thirds of the cervical
region, and having a space equal to its vertical diameter inter-
vening between it and the lower extremity of the neurapophysis :
and here I may observe that the character afforded by the rela-
tive extent of this space is a very useful one, as it is variable in
the species but constant in each ; and as it is indicated by the
centrum alone, it serves as a term of comparison when the other
elements of the vertebra may be lost. The articular base of the
neurapophysis is bounded below by two lines meeting at an open
angle. From tlie apex of this angle to the articular process the
distance is less than the extent of the centrum below the apex.
The spines are compressed throughout, slightly curved back-
wards, with the anterior angle and apex rounded off. This cha-
racter is gradually changed at the base of the neck for a quadrate
form of the spine with a straight truncate apex ; and towards
the posterior part of the dorsal region this apex is slightly
thickened.

The height of the spine is to its antero-posterior diameter as

BRITISH FOSSIL REPTILES. 59

8 to 5 through the greater part of the dorsal region. The tail
includes 2^ lengths of the head, and from the posterior end of
the ischia consists of 35 vertebrae. The same general form and
proportions of the vertebrse are preserved throughout the verte-
bral column ; and it is this fact, established upon a comparison
of four nearly entire specimens in the collections of the British
Museum and of Mr. Hawkins, which enables me to speak with
confidence of the specific importance of well-marked characters,
-though they may be afforded by detached vertebrae only.

I have few observations to offer on the specific peculiarities
of the head of the PL Hawk'msii, as it is principally from the
perfect specimens of this species that the description of this
part in the general account of the Plesiosauri has been taken.
Its specific character will be manifest when I come to compare
with it the head of the PL macrocephalus. I may remark here,
however, that the orbit occupies a position halfway betv/een the
occipital condyle and the end of the snout. The bones have a
smooth surface, except at the anterior part of the head, where
there are many pits and grooves, like those in the head of the
Crocodile. The teeth participate in the general character of the
Plesiosaurian type, being long, slender, slightl)^ recurved, finely
but distinctly grooved in the longitudinal direction on the outer
surface, w^ith a long pulp-cavity within. There are about 40
teeth on each side of the upper and 35 on each side of the lower
jaw : those towards the anterior extremities of the jaws are
longer than the rest, but the disproportion is more strongly
marked in other species than in the present.

EA'tremities. — The fore and hind extremities of this species
are nearly equal in size, but the latter are a little longer.

The pectoral arch accords with the general Plesiosaurian
type.

The sternum has no median process ; it presents a well-marked
concavity anteriorly.

The anchylosed scapula and clavicle form a triradiate bone, of
which the scapular portion is short and compressed, directed
obliquely backwards at an angle of 45° with the clavicular part,
and equalling two thirds of the extent of this bone.

The coracoid equals in antero-posterior extent eight of the
cervical vertebrae immediately anterior to it.

The humerus equals in length 6^ of the posterior cervical
vertebrae : its anterior margin is slightly convex : the breadth
of its distal flattened extremity equals twice its length.

The radius is longer than the ulna, the breadth of which docs
not quite equal its length.

Six appears to be the normal number of carpal bones.

60 REPORT — 1839.

In the hinder extremity the bones of the pelvic arch first
claim attention. The ileum is flattened and slightly expanded
at its superior free extremity, where it rests upon the sacral
ribs; its length is equal to four of the contiguous vertebras.
The pubic bones are in the form of large square-shaped plates,
with the angles i-ounded off, and a deep smooth emargiuaiion at
their posterior edge, which is turned towards the corresponding
emargination of the ischium to form the 'foramen ovale.' The
outer and posterior angle is marked by the articular surface
contributed by the pubis to the formation of the acetabulum.
The antero-posterior extent of the broad pubic bone equals in
this species nearly four of the parallel vertebras.

The ischia present the form of inequilateral triangles, and are
straighter at their mesial edges than are the pubic bones : they
present a concavity at each of the other margins ; which is
deepest at the shorter and anterior margin. The length of the
ileum exceeds that of the pubis. The extent through which the
median margins of the ischia are joined to each other exceeds
that in other species of Plesiosaur.

The femur is more slender in the shaft than the humerus, but
is of the same length : its distal flattened extremity is less ex-
panded.

The tibia and fibula are more nearly equal in length than are
the corresponding bones of the fore paddle ; the breadth of the
reniform fibula equals its length. There are at least five bones
in the tarsus of this species. That which is wedged into the
interspace between the distal extremities of the tibia and fibula
is characterized by a concave notch at its tibial margin. The
number of digital phalanges, in addition to the metatarsal row,
corresponds with that given in the description of the generic
type.

Full-grown individuals of this species appear to vary from 7
to 7i feet in length.

Localities. — The Plesiosaums HawJcinsii is most common
in the lias quarries near Street. It occurs at Lyme ; but is less
common there than the PL dolichodeirus and PL macroce-
phalus next to be noticed.

Vertebrae of this species have been found in the lias at Weston
near Bath ; in the lias bone-bed at Aust-Clift' in the neighbour-
hood of Bristol, and in that of the Pyrton passage on the Severn.
I have not yet seen any specimens referrible to this species from
the lias of Whitby or from that of Boll in Wirtemberg.

Plesiosaurus dolichodeirus.

The admirable description and restoration of this species

BRITISH FOSSIL REPTILES. 61

given by Mr. Conybeare in the second part of the first volume
of the second series of the Geological Transactions leaves little
to be said excepting in regard to those points in vt'hich it differs
from the PL Hawkinsii.

The head is relatively smaller in proportion to the body;
forming less than the thirteenth part of the whole length of the
skeleton, while in the PL Hawkinsii it forms less than one
tenth part.

This diminutive head was supported on a longer neck. In
the PL Hawkinsii the head is three times the length of the
neck ; while in the PL dolicliodeirus it is four times that
length. Mr. Conybeare states that the nock of the PL dolicho-
deirus is fully equal in length to the body and tail united ; but
in Hawkins's Plesiosaur the length of the neck only slightly
exceeds that of the body or trunk ; and this difference depends
both on a difference in the number as well as in the form of the
cervical vertebrae.

The cervical vertebrae in the PL dolicliodeirus, reckoning as
such those which supported hatchet-shaped, and not rib-like,
lateral appendages, are, according to Mr. Conybeare, thirty-
five in number ; while the corresponding vertebrae in Hawkins's
Plesiosaur are twenty-nine in number. The cervical vertebrae
in the latter are also shorter in proportion to their breadth than
are those of the PI. dolichodeirns.

The dentary bone has a shorter and less expanded symphy-
sial portion, and the anterior teeth have a smaller proportional
size than in the PL Hawki?isii or PI. macrocephalns.

A lower jaw of this species in the collection Miss Philpotts,
measures

In. Lin.

in length 5 8

in breadth behind the teeth .... 3 G
The number of teeth in this lower jaw was 50 (25-25).

The spinous processes of the vertebrae are more compressed
laterally in the PL dolichodeirns than in any other species of
Plesiosaurus which I have seen.

A more readily appreciable difference is presented in the
forms and relative sizes of the ulna and tibia in these nearly
allied species. In the PL dolicliodeirus, the ulna, or posterior
of the two bones which succeed the humerus, is as long as the
radius ; and its margin next the radius is but slightly concave.
In Hawkins's Plesiosaur the ulna is shorter than the radius,
broader in proportion to its length, and with a deeper concavity
on its inner margin.

In Hawkins's Plesiosaur, the fibula, in regard to its relative

m tlEPORT~-1839.

length and breadth, and its bent or reniform figure, and parti-
cularly with respect to the curvature of its outer margin, de-
viates in a greater degree than the ulna from the corresponding-
bone in the PL dolichodeirus. The differential characters af-
forded by the bones of the fore arm and leg are the more satis-
factory, because, as we shall presently see, the Fl. macroce-
phalus again presents different and characteristic forms of the
same bones. There are other and slighter differences in the
shape of the hatchet-bones, or cervical ribs, of the humerus and
of the femur.

The length of the skeleton described by Mr. Conybeare is
nearly ten feet.

Localities. — The most common places of deposit of the bones
of tliis species are in the lias of Somersetshire at Watchett,
Bath and Bristol ; and in that of the valley of Lyme in Dorset-
shire. I have likewise seen detached vertebras of the PI. doli-
chodeirus from the lias of Bitton in Gloucestershire.

Plesiosaiirus macrocephalus.

The characters of this interesting species I have fortunately
been able to study, not only in detached bones in different col-
lections, but also in an almost entire specimen liberally placed
at my disposal for that purpose by Viscount Cole.

As, however, only a portion of the tail is preserved in this
unique specimen, the total number of vertebrae characteristic of
the PL macrocephalus still remains to be ascertained.

The cervical region of the spine in this species exhibits the
prominent character of the genus in its great extension. It is,
however, only twice the length of the lower jaw, instead of three
times the length of the same part, as in the PL Hawkinsii ; and
this difference, arising from the greater development of the head
in the PL macrocephalus is associated, as Dr. Buckland has ob-
served,with thicker and stronger vertebrae in relation to the greater
weight they had to sustain. It includes twenty-nine cervical
vertebrae. In the twentieth cervical vertebra of PL HatuMnsii,
the transverse is to the antero-posterior diameter as 4 to 3. In
the corresponding vertebra of the PL rnacrocephalus the trans-
verse is to the antero-posterior diameter very nearly as 2 to 1.
The rest of the cervical vertebrae bear a similar ratio to those of
the PL Hawkinsii ', the bodies of the vertebrae therefore in PL
macrocephalus, although by no means so flat as in the Ich-
thyosauri, make an evident approach to the characteristic form
of the vertebrae in that genus.

In the PL Hawkinsii the hatchet-shaped processes are con-
verted into stjdiform ribs at the twenty-ninth cervical vertebra ;

BRITISH FOSSIL REPTILES. 6^

but in the PL macrocephaliis they undergo this change of form
at the twenty-seventh cervical vertebra, and perhaps at the
twenty-fifth ; but this appendage is lost in the skeleton under
consideration.

Hence we may conclude that the PL macrocephalus has two
vertebrae less in the cervical region than the PL Haivkinsii,
and probably six cervical vertebrae less than the PL dolicho-
deirus, in which Mr. Conybeare states that ^' the thirty-five an-
terior vertebrae exhibit these (hatchet) processes distinctly cha-
racterized, and are therefore, beyond all doubt, cervical*."

The articular surfaces for the ribs on the anterior cervical
vertebrae of the PL macrocephalus are relatively larger and have a
more regular lozenge-shape than in the PL Haivkinsii, in which
they are elongated in the axis of the vertebra. They are tra-
versed (as mentioned in the general characters of the JPlesiosau-
rian vertebrae,) by a longitudinal groove ; this gradually sinks
from the middle of the depression towards its lower margin,
and at length, at the twenty-third cervical vertebra, disappears.

The depressions above the costal surfaces for the lodgement of
the bases of the neurapophyses resemble in form those of the
PL Hawkinsii, but extend further down upon the side of the
centrum. They are co-extensive with the antero-posterior dia-
meter of tlie vertebral body, and are bounded by two lines meet-
ing below at a right angle. The angle formed by the corre-
sponding lines in the PL Haiukiiisii is more open. The di-
stance between these neurapophysial pits and the costal pits in
the anterior cervical vertebrae, differs in different species of Ple-
siosaiirus. In the PL macrocephalus the interspace is very short,
never exceeding half the diameter of the costal pit, even in the
most anterior of the costal vertebrae. In the PL Haivkinsii
the interspace is equal to double the diameter of the costal pit
in the corresponding vertebrae.

There may also be observed in the PL macrocephalus an evi-
dent tendency in the surface supporting the cervical vertebrae to
rise above the level of the centrum ; and this is the more inter-
esting as in a large species of Plesiosauriis allied to PL ma-
crocephalus (the PL arcuatus subsequently to be characterized)
the surface on the centrum, and the corresponding surface of
the neurapophysis do project as short transverse processes, and
thus approximate to the Crocodilian type.

As the seventh, eighth, and ninth vertebrae happen to be dis-
placed in Lord Cole's specimen, and their neurapophyses to be
dislocated, the form and breadth of the articuhu* depressions for

* Loc. cit., p. 384.

G4 REPORT— 1839.

the neurapophyses, ns well as the canal for the spinal marrow,
are thus brought into view. The centrum presents only a plane
surface for the spinal cord, the rest of the canal being com-
pleted by the neurapophyses laterally, and the expanded base of
the spine above. The surface in question is bounded by two
lateral curved lines, having their convexities turned upwards to-
wards each other. Immediately below, and external to this
surface on each side, are the deep and roughened pits for the
attachment of the neurapophyses.

The cervical neurapophyses do not in any of the Plesiosaurs
unite immediately together above the spinal cord and canal, so
as to form a continuous bony arch, spanning across that part ;
but they stand upright from their sockets in the vertebral body,
parallel with each other, or only slightly converging at their
superior extremities. They terminate above, in young indivi-
duals at least, in brqad rough articular surfaces parallel with
the transverse axis of the vertebrae, but sloping down from be-
hind forwards with a slight sigmoid flexure at an angle of 25°
with the longitudinal axis of the vertebra.

In the same way, therefore, as the rib, or appendage to the
transverse processes, is bifurcate at its proximal extremity, in
those cases where the two transverse processes are separately
developed on each side of the vertebra, and where the rib is
joined to both ; so here the spinal appendage of the neurapo-
physes is bifurcate at its proximal extremity, and each fork
rests upon the above- described oblique articular process of its
own side.

This analogy between the lateral or costal, and the superior
appendages of the vertebral centre, is one which the Plesiosau-
rtis alone has hitherto afforded.

But besides the two surfaces developed for these articulations
with the neurapophysis, each fork of the spine sends off an ar-
ticular or oblique process from its anterior and posterior extre-
mity ; the articular surface looking obliquely upwards and in-
wards on the anterior process, and downwards and backwards
on the posterior process : and thus the spines are locked toge-
ther throughout the whole vertebral column with the exception
of the terminal vertebrae of the tail.

In adult individuals of the PL macrocephalvs, these separate
elements of the superior arch become anchylosed together, as is
the case in a great part of the spine in the present specimen.

In a Plesiosaurian cervical vertebra, however, measuring
seven inches and a half in vertical extent and three inches
and a half in transverse diameter, in the collection of Mr. Haw-
kins, I find the neurapophyses distinct both from the spine

BRITISH FOSSIL REPTILES. G5

above and the centrum below. But in other cervical vertebrae
of a still larger Plesiosaur in the collection of Lord Cole, not
only is the spine anchylosed with the neurapophyses, but these
are also confluent with the centrum.

In the dorsal region in the PL inacrocephaius, as in the PL
Hawkinsii and PL dolichodeirus, the neur apophyses and spines
become anchylosed ; but the former elements continue separate
from the body of the vertebra throughout the vertebral column
in the PL macrocephalus.

The cervical spines in the PL macrocephalus differ in form
from those of PL Hawkinsii in retaining their breadth or an-
tero- posterior extent throughout the neck ; their extremities
being, as it were, truncate, with the angles slightly rounded off.
The powerful ridge of bone which they thus collectively form
is highly characteristic of this species. The consequence of
this structure is a diminution of the spinal interspaces necessary
for the vertical inflections of the neck ; which interspaces are
conspicuously present in the PL Hawkinsii, where the end of
each cervical spine is as it were obliquely cut off at the ante-
rior part, so as to allow the neck to be bent upwards much
more extensively than could have been possible in the PL ma-
crocephalus. What, however, the latter species thus lost in
mobility it gained in strength, the quality mainly required in
relation to the movements of its more bulky and ponderous head
and jaws.

As the powerful neck of the PL macrocephalus, however,
possessed extensive mobility in the lateral direction, as is indi-
cated by its position in Lord Cole's fossil, the muscles destined
for these movements must necessarily have been developed in a
corresponding degree ; and we find that adequate provision was
made for their fixed points of action, in the superior develop-
ment of the costal processes, as compared with those of PL
Hawkinsii : these processes present, indeed, throughout a
greater part of the neck the clfaracteristic expansion of their
distal extremities, which led to their being called hatchet-
shaped bones by Mr. Conybeare : but the stem which supports
the dilated extremity is proportionally longer in the PL macro-
cephalus-, and it is only towards the baie of the neck that
the extremities overlap each other, as in the Crocodile. Dr.
Buckland has illustrated this peculiarity by placing side by side
the figures of the hatchet bones in the PL Hawkinsii and PL
macrocephalus in his Bridgew^ater Treatise. These cervical
ribs assume the true costal form, as before stated, at the twenty-
seventh vertebra, where they are short and straight ; behind tins
VOL. VIII. 1839. F

C6 REPORT — 1839.

part they progressively increase in length, and become bent to-
wards the sternal region.

The cervical vertebrae gradually increase in all their dimen-
sions (least so however in their antero-posterior extent) as they
approach the trunk ; but the difference in their size at the two
t^xtremities of the neck is less than in the PL dolichodeirus.

Dorsal Vertebrce. — -These are characterized, according to
the previous definition, by the absence of articular surfaces on
the centrum for ribs, and by the development of a superior
transverse process, which exclusively supports the rib, from the
base of each neurapophysis. The number of vertebrae so cha-
racterized is twenty ; that of the corresponding vertebrae in the
PL Hawkinsil is twenty-three.

These vertebrae include, besides the ordinary dorsal, those
which occupy the situation of the lumbar or ribless vertebrae in
the Crocodile ; but there are no such vertebrae in the trunk of
the Enaliosaurs, which in this respect agree with many Lacer-
tians.

The special characteristic of the dorsal vertebrae in the PL
macrocephalus, as compared with the PL Haiv/einsii, consists
in their being, like the cervical, more flattened in the antero-
posterior direction and more concave at the sides ; in which
flatter particular they resemble the dorsal vertebrae in the PL
dolichodeirus more than those of the PL Hawkinsii.

At the commencement of the dorsal series the lower margin
of the neurapophyses is angular, as in the neck ; but towards
the middle of the back they become rounded, and the articular
depressions in the body of the A^ertebra present a correspond-
ing form. The transverse processes progressively increase in
length towards the middle of the trunk, and again diminish as
they approach the tail ; the bases of the neurapophyses from
which they rise diminish in vertical extent in the same ratio,
and leave a greater proportion of the centrum free from their
embrace. The increasing length and upward inclination of the
transverse processes supporting the ribs, Mr. Conybeare has
justly observed, " seem intended to give a wider sweep to the
ribs," and relate to the acquisition of greater expansion of the
thoracic-abdominal cavity at the part where the largest viscera
were lodged. The spinous processes at the beginning of the
dorsal region diminish in antero-posterior extent, but slightly
increase in height ; they then increase in both dimensions to the
middle of the back, and thence gradually decrease to the tail.

Sacral Fertehrcs. — There are no sacral vertebrae by anchylo-
sis in the Plesiosaurs. In Lord Cole's remarkable specimen of

BRITISH FOSSIL REPTILES. 67

the present species the costal articular surface begins to descend
from the neurapophysis upon the body at the fiftieth vertebra,
and this and the succeeding vertebra may consequently be
reckoned as sacral ; their relative position to the dislocated
ileum verifies the supposition that the same character, with re-
ference to the costal articular surface, points out the sacral ver-
tebrae in the PL macrocephalus, as it does those of the PL
HawJiinsii. The surface which supported the spinal marrow
in the sacral vertebra is small and flattened, slightly impressed,
bounded by two gently curved lines, whose convexities are turned
towards each other. A comparison of the medwUary canal at
this part and at the cervical region shows that the usual law of
the increase of the spinal cord at the parts where larger nerves
were required to be given off to supply the locomotive extremi-
ties, obtained in the extinct Enaliosaurs, but only in the same
degree as in their existing cold-blooded congeners.

In the caudal vertebrae the length of the centrum is to its
transverse diameter as 2 to 5.

Extremities. — In the bones of the paddle, or radiated ap-
pendage of the pectoral arch, the following diiferences exist be-
tween the PL macrocephalus and PL Hawkinsii. The hu-
merus, as was before observed in the description of the PL
Hawkinsii, is less contracted at its proximal extremity, and
less curved backwards ; the anterior margin being rather con-
cave, instead of convex as in the PL Hawkinsii ; it is also
broader in proportion to its length ; its greatest breadth (at
the distal extremity) being more than half its length, while in
PL Haivkinsii it is less, being about f ths of the same length.
The distal end terminates in a slight but reguly,r convex curve,
while in PL Plawkinsii the separate facets for the radius and
ulna are distinctly marked, and meet so as almost to form an
obtuse angle.

In the Plesiosaurs generally the radius is nearly straight,
while the ulna is bent with the concavity towards the radius :
both bones are flattened, as in other Enaliosaurs. In PL ma-
crocephalus the margin of the radius next the ulna is more con-
cave than in PL Haivkinsii, and the bone is relatively broader
at its distal extremity, which is terminated by a convex, instead
of a nearly straight, line. The ulna equals in length the radius,
as in the PL dnlichodeirus, while it never attains the same
length in the PL Haivkinsii ', it is also relatively broader than
in either the PL dolichodeirns or PL Haivkinsii ; and presents
a more regular reniform figure j the humeral articular surface
not being so straight, or so distinctly marked off from the outer
convex margin. The carpus consists, in the PL macrocephalusy

V 2

68 REPORT— 1839.

of eight instead of six ossicles, as in the PL Haivkinsii. The
fourth or additional one in the first or proximal row is wedged
in between the ulna and the third carpal bone, at the outer an-
gle of the carpal joint ; it is much smaller than the rest.

The relative sizes also of the three normal bones of the first
row is different ; in the PL Hawkindi the middle one is the
largest, the radial or anterior one least : in the PL niacroce-
23halus the ulnar or posterior of the three is, if anything, the
largest, and the radial bone not so much smaller than the other
two. The disproportionate size of the two posterior bones in
the PL Hawkinsii compensates for the shortness of the ulna.
In the distal row of the carpus the superadded bone in PL ma-
crocephalus is a very small ossicle wedged in between the third
or posterior carpal, and the fifth or ulnar metacarpal bones.

The metacarpal bones correspond with those of PL Hmvkin-
sii ; the radial or anterior one, which corresponds to the pollex,
being the shortest and broadest.

PL 7nacrocephalus* . PL Hawkinsii.

The 1st or radial metacarpal supports 2 (but probably 3 phalanges) 3.

The 2nd metacarpal 6 6or7?

The3rdditto 9 8 or 9 ?

The 4th ditto 8 .'. 8.

The 5th ditto 6 6*.

The evidently natural curve formed by the distal phalanges in
Lord Cole's PL 7nac7r}cephahis indicates that the paddles were
more flexible at their tapering extremity than those of the mo-
dern Cetacea.

Pelvic Extremity. — The femur in PL macrocephalus is re-
latively longer than in PL Haivkinsii or dolichodeirus. In the
latter it equals the humerus in length ; in the former it exceeds
the same bone by one eighth.

In the PL macrocephalus it is rather more expanded at the
distal extremity than in the PL Hawkinsii, but the difference
of form is not so well marked as in the humeri of these two
species. The bones of the leg have the same distinguishing cha-
racter as those of the fore-arm ; and the fibula, in all the Plesio-
saurs, corresponds to the ulna in its peculiar bent figure.

In the PL macrocephalus the fibula is, however, relatively
broader than in the PL Haivkinsii, notwithstanding that, like
the ulna in the fore-arm, its distal extremity is on the same plane
with that of the adjoining bone. It is, in fact, fully as broad as

* In the enumei-ation of phalangeal bones by Mr. Conyheare (GeoL Trans.
1824, p. 387,) the metacarpals are included; allowing for this, the perfect di-
gits of the PL dolichodeirus correspond in number with PL HawJcinsii and
macrocephalus.

BUniSH FOSSIL UEI'TILES. 69

it is long ; which proportions distinguish it from the fibula of
either the PL Haivkinsii or PL dolichodeirus.

The tarsus consists, in PL macrocephaliis, of six, instead of
five bones as in the PL Haivkinsii. It participates in the pe-
culiarity of having those bones, which are situated at the ante-
rior or tibial side of the joint, much smaller than those of the
fibular side, and so placed between the tibia and tibial metatar-
sals as to indicate that the foot had a freer inflection forwards,
or upon the tibia, than in the opposite direction.

In the PL Hawkinsii the interspace between the tibia and
metatarsals is occupied by a single round flat bone 5 but in the
PL macrocephalus by two ; the additional bone being situated
at this part of the tarsus.

The metatarsals resemble in number and disposition those of
the PL Haivkinsii. In the general form and proportions of the
phalanges of both extremities a close resemblance exists be-
tween the two species.

Localities. — This species occurs in the lias of the valley of
Lyme : also, but more rarely, in the lias of Street. I have
seen detached vertebrae of the PL macrocephalus from the lias
of Weston near Bath.

The vertebrae of the Plesiosaurus, included by Professor Jae-
ger in his list of the fossils of the lias of Boll in Wirtemberg,
approach more nearly to the characters of the PL macrocephalus
than they do to any other well-determined species.

Plesiosaiirus brachycephalus.

This species, in the strength and comparative shortness of its
neck, and in the proportions of its extremities, is most nearly
allied to the Plesiosaurus macrocephalus ; but it differs from
that species in the form of its head, and in the character of its
cervical vertebrae.

In the nearly complete skeleton of the PL hrachycephalus,
preserved in the Museum of the Philosophical Society of Bris-
tol, 75 vertebrae may be counted, and only a few seem to be
wanting from the extremity of the tail. Of these at least twenty-
eight may be reckoned as cervical, according to the characters
assigned to this series of vertebrae in the introductory part of
the present Report. The length of the bodies of these vertebrae
does not quite equal their transverse diameter. The vertical dia-
meter of the body of the 13th cervical vertebra was 1 in. 5 lines,
the antero-posterior diameter 1 in. 2 lines. The anterior and
posterior articular surfaces of the body are gently but regularly
concave without any median convexity. The costal depres-

70 REPORT — 1839.

sions are elliptical, narrower than in the PL macrocephalusy but
broader than in the PL Hawkinsii. In the 20th cervical ver-
tebra the costal is situated immediately below the neurapo-
physial pit ; but in the vertebrae anterior to this, they are sepa-
rated from the neurapophysial pits by a space equal to their own
breadth. This is a character which distinguishes the present
species very satisfactorily from the PL macrocejjhalus. From
the PL Haivkivisii it differs in the greater relative size of
the cervical vertebrae ; and especially in the superior height of
the neurapophyses, which fully equals the vertical diameter of
the vertebral body.

The anterior and posterior margins of the sides of the verte-
bral body are impressed with fine irregular longitudinal ridges,
but the midspace between the costal and neurapophysial de-
pressions is quite smooth. The spines of the anterior cervical
vertebrae are obliquely truncate at the anterior margin, and are
less square-shaped and less strong than in the PL macrocepha-
his. The characteristic vascular foramina on the inferior sur-
face of the centrum lie in deep concavities, and are separated
by a longitudinal ridge. This ridge gradually disappears in the
dorsal vertebrae, and the vascular foramina become more widely
separated and approach the lateral aspects of the centrum. The
length of the 15th cervical vertebra is 1 in, 8 lines, its ver-
tical diameter 2 in. 2 lines.

From the position in which the vertebrae lie in their lias ma-
trix, it wovild seem that an elastic intervertebral cushion of from
two to three lines thick had been interposed between their bo-
dies. The cervical ribs have their expanded or hatchet-shaped
extremities supported on longer pedicles than in the PL doli-
chodeirus or Hawkinsii. and in this respect they resemble
those of the PL macrocejjhalus. The spinous processes of
the dorsal region are stout and broad, quadrilateral, truncate
above, and with the angles very slightly rounded off ; they are
somewhat longer than those of the cervical vertebrae. The cau-
dal vertebrae appear to be less numerous than in the PL doli-
chodeirus or PL Hawkinsii.

The caudal ribs appear to be expanded at their extremities,
somewhat analogously to the cervical ribs ; the depressions on
the sides of the vertebrae to which they are articulated are round,
and have their margins raised ; they are situated immediately
beneath the neurapophysial pits in the posterior caudal vertebrae.
The under part of the caudal vertebrae is concave, and presents
two vascular foramina on each side, separated by wide inter-
spaces.

BRITISH FOSSIL RKPTILES. 'Jl

The head is shorter in proportion to its breadth than in any
of the previously described Plesiosauri; whence the specific name
proposed for this species.

There are twenty-six teeth on each side of the lower jaw, the
terminal portion of which is less abruptly expanded than in the
PL grandis or arcuatus. One of the large anterior teeth of
this species measures one inch and a half in length and one
third of an inch in breadth ; its transverse section is nearly cir-
cular. The crown of the teeth is sculptured with well-marked
and finely- waved longitudinal grooves.

The breadth of the distal end of the humerus equals half the
length of the bone, which is nine inches ; the form of that bone
is the same as in the PL macrocephalus. The other bones of
the anterior paddle are not sufficiently complete to aid in cha-
racterizing the present species. In the posterior extremity the
ischium differs from both that of PL doUchodeirus and PL Haw-
Idnsii in the greater width and less deep concavity of its anterior
margin ; from which may be inferred a corresponding modifica-
tion of the pubis, where that bone combines with the ischium
to complete the abturator foramen. The mesial margin is more
convex than in the PL Haivkinsii.

The femur is a tenth part longer than the humerus, and its
distal extremity is relatively less expanded : its anterior margin
is less concave than in the PL macrocephalus. It measures
nine inches nine lines in length.

The tibia is somewhat narrower and its anterior and posterior
margins less curved than in the PL macrocephalus. The
fibula approaches more nearly in form to that of the PL ma-
crocephalus than to the fibula of any other species of Plesio-
saurus ; but its tibial margin is more extended and less deeply
(ton cave. Its breadth is equal to its length, which is only two
lines less than that of the tibia. The tarsal bone next the in-
terspace of the tibia and fibula is not emarginate.

The total length of the skeleton of the PL hrachycephalus
from the Bitton lias is ten feet and a half. The length of the
head is one eighth of the entire length of the skeleton, or equals
tlie nine anterior cervical vertebrae.

Localities. — The incomplete skeleton of this species in the
Museum of the Bristol Philosophical Institution was discovered
in the lias at Bitton, Gloucestershire, in 1830.

Several vertebrae in the Gymnasium at Stuttgard, from the lias
of Boll, appear to belong to the present species.

Vertebrae of the PL hrachycephalus also occur in the lias at
Whitby.

72 REPORT— 1839.

I have not met with any specimens from the Dorsetshire or
Street lias referrible to this species.

Plesiosaurus macromus.

In the PL doUchodeirus and Hawkinsii, which may be re-
garded as the typical species of the present most singular genus,
the anterior and posterior paddles are of equal size. The PL
macrocejihalus and bracJiycephalus are distinguished in addition
to other characters by the superior length of the hinder paddles.
In the present species the contrary proportions prevail ; here vre
lind at length an instance in which the Plesiosaurus resembles
the Ichthyosaurus, in the superior size of the anterior as com-
pared with the posterior extremities ; and the equality of the
locomotive members, as respects their length, proves to be a
specific and not a generic character. A considerable proportion
of the skeleton of the PL macromus was discovered by Miss
Anning in the lias near Lyme, and now forms part of the valu-
able collection of Miss Philpotts. These interesting remains
include the greater part of the vertebral column, with tlie prin-
cipal bones of the anterior and posterior extremities ; but the
skull and teeth are unfortunately wanting.

The cervical vertebrae resemble those of the PL doUchodeirus
in their general form and proportions, and in the relative posi-
tion of the neurapophysial and costal surfaces in the anterior
cervical vertebras, but differ in the character of the articular
surfaces of the centrum. The body of one of the vertebra? from
the middle of the neck gives the following admeasurements :

Inch. Lines.
Length or antero-posterior diameter. . 1 4

Vertical diameter 1 4

Transverse diameter 1 6

The anterior and posterior articular surfaces are gently and
uniformly concave, without the central rising described by Mr.
Conybeare in the PL doUchodeirus, and which is present in
some other species. In many of the vertebrae of the present
specimen there is a transverse linear impression in the centre
of the above-mentioned articular surfaces. The lateral surfaces
are sculptured at the anterior and posterior margins by nume-
rous longitudinal irregular grooves ; the intermediate surface
is comparatively smoother. A narrow vertical ridge is con-
tinued from the descending angle of the neurapophysial de-
pression to the middle of the upper costal surface. The di-
stance which intervenes between the neurapophysial and coetal

BRITISH FOSSIL REPTILES. 7-3

articular surfaces is nearly equal to the vertical diameter of the
latter. The costal pits are slightly raised above the surround-
ing surface ; they are of a transversely elliptic form, and with a
greater vertical breadth than usual ; they are also separated by
a deeper and wider channel than in the PL Hawkinsii. The
under sm-face of the vertebrae is traversed along its middle by a
smooth broadish ridge, on each side of which is the charac-
teristic foramen, of an elliptical form. The longitudinal ridge
disappears in the dorsal vertebrae. The sides of the neurapo-
physial depressions meet at nearly a right angle. The spinous
process is less extended in the antero-posterior direction than
in the PL macroceplmlus, but is thicker (transversely) than in
the PL doliclwdeirus.

The dorsal vertebrae are a little shorter than the cervical :
they have the same anterior and posterior articular surfaces ;
but the lateral surfaces are smoother and more concave. In
the caudal vertebrje the inferior surface of the centrum is flat-
tened : the hsemapophysial pits are well marked, especially the
anterior part. The humerus of this species has the same form
as the bone of the Plesiosaurus figm-ed by Mr. Conybeare in
the 1st Vol. 2nd Series of the GeoL Trmis. pi. xxii. fig. 1 : it is
expanded immediately below the head by the development of
two rough protuberances for the insertion of muscles : below
these the shaft of the bone continues to diminish gradually in
thickness and increase in breadth to its distal extremity. The
contour of the anterior and posterior margins resembles that of
the same parts in the PL doliclwdeirus , the anterior being
slightly convex, the posterior in a greater degree concave : the
distal extremity is bounded by a pretty regular convex curvature.

The rough muscular surfaces on the inner side of the bone
near the proximal extremity are only slightly raised above the
smooth surrounding surface, and they are so close together as to
be nearly confluent. The external tubercle is as it were sepa-
rated by a compression from the general proximal surface. At
the distal extremity the rough articular surface is divided into
two parts by a shallow depression on the internal or sternal
side of the bone ; at the junction of the middle with the pos-
terior third of the distal curve.

Inches. Lines.
The length of the humerus is ... 8 6

The breadth of the distal end ... 3 10

The radius presents the common form, is more expanded at
the proximal than the distal end, compressed, and with the an-
terior and posterior margins concave. The ulna is as long as

74 REPORT -1839.

the radius, and resembles both in this proportion and in its
tshape that of the PL dolichodeirus : its radial or anterior con-
cavity is less deep, and the posterior margin less convex than
in the PL Haivkinsii or PL ynacrocephalus.

Inches. Lines.

The length of the ulna is 3 6

The breadth 2 2

The femur differs in form as well as in size from the humerus :
its anterior as vrell as posterior margin is slightly concave ', and
it is upon the whole somewhat shorter and thicker in propor-
tion to its length. Near the proximal extremity there is a rough
muscular protuberance corresponding with that in the humerus,
but more circumscribed and more raised. The distal end is
bounded by a pretty regular convex curve, and its rough arti -
cular surface is in the form of a compressed ellipse, not en-
croached upon by any depression as in the humerus.

Inches. Lines.

Length of the femur 7 8

Breadth of its distal end 3 6

The tibia like the femur is thicker as well as shorter than
the corresponding bone in the fore-arm.

Inches. Lines.

Length 3

Breadth of the proximal end ... 2 3
distal end 1 7

The remaining bones of the extremity are not sufficient in
number to enable me to recompose the entire extremity so as
to compare together the bones of the hand and foot : but the
proportions above described of the larger bones of the anterior
extremities are sufficient to distinguish the present from any
other known species of Plesiosaur. The only doubt which oc-
curred was with reference to the fact of the humerus and femur
having actually belonged to the same skeleton ; but the corre •
spondence of the bones in texture, colour and general appear-
ance, and in the rough surfaces for muscular attachment, coin-
ciding with the evidence of the indefatigable and acute discoverer.
Miss Anning, as to the proximity of all the remains of this
specimen in the lias matrix, assured me that the comparison
might be safely made.

Plesiosaurus pachyomus.

A new species oi Plesiosaurus is indicated by certain remains,
in the collection of Prof. Sedgwick, from the greensand of
Reach about six miles from Cambridge.

BRITISH FOSSIL REPTILES. 7^

The humerus, or femur, is remarkable for its thickness, whence
the specific name proposed for this species ; its distal flattened
extremity is one inch and a half thick, the breadth of the same
part being only four inches and a half, and the lengtli of the
entire bone nine inches and a half. The contour of the head is
transversely oval. The central part of the bone is occupied by
a coarse cellular structure, one inch and a half in diameter,
surrounded by dense osseous walls three lines thick.

The body of a cervical vertebra of this Plesiosaurus measures

Inches. Lines.

in longitudinal diameter 1 7

in transverse 2 .3

in vertical 1 9

The distance between the neurapophysial

and costal pits is 1 :

the form of the costal pit is a full transverse ellipse, and there
is a transverse depression about three lines in length in the
centre of the articular surface of the body. The neurapophysial
pits are much wider in the dorsal than in the cervical vertebrae.
The sides of the vertebrae are smooth and slightly concave.

Plesiosaurus arcuatus.

Under this name I designate a species of Plesiosaurus, of
which I have been able to study parts of the skeleton in the
British Museum (from the collection of Mr. Hawkins), in the
Bristol Museum, and in the collections of Lord Cole and Prof.
Sedgwick.

The vertebrae, especially those at the posterior moiety of the
cervical region, are characterized by the development of distinct
transverse processes from the sides of the centrum for the sup-
port of the cervical ribs. These processes have the articular
surfaces traversed by a longitudinal groove, as in other Plesio-
sauri, and consequently thus present the appearance of the two
normal transverse processes confluent at the base. The arti-
cular surfaces on the anterior and posterior sides of the body of
the vertebra present the true Plesiosaurian character, being
slightly concave with a gentle central convexity. The lateral
and inferior surfacesof the vertebral centre are smooth and con-
cave. Theneurapophysis from its base to the summit of its oblique
process is equal in vertical extent to the rest of the vertebra
below : the inner surface of the neurapophysis is traversed in
its middle by a longitudhial ridge, (at least in the posterior cer-
vicals,) probably for the attachment of the membrane of the
spinal cord. The spinous process of the neurapophyscs is high

76 REPORT 1839.

and broad, but is more particularly characterized by the lateral
expansion of its summit, the anterior angle of which is obliquely
truncated, presenting at that part a flattened surface.

The vertical extent of the entire cervical vertebra here de-
scribed is 7 inches. The vertical diameter of the centrum 2|
inches ; its transverse diameter the same ; its antero-posterior
diameter 2^ inches. In its general proportions this vertebra has
most resemblance to the corresponding one of the PL macroce"
phalus, but it differs in the presence of the transverse processes,
and in the form, and especially the superior expansion of the
spine.

The dorsal vertebrae are distinguishable by the correspond-
ingly great development of the transverse processes upon the
neurapophyses.

The episternal bone of this species is figured in Mr. Hawkins's
26th Plate. It measures 1 6 inches and ^rd in transverse extent.
The arc of its anterior concavity, which is less deep than in PL
Maiv/cinsii, measures 8 inches. The lateral alee are slightly
convex externally, and terminate posteriorly at an acute point.
It is much flattened, thickest in the middle, from the internal
surface of which a longitudinal ridge is produced.

The humerus of the same skeleton measures 14 inches long,
and 7 2 inches broad at its distal extremity. The anterior surface
is slightly concave, as in the PL macrocejihalus. The tuberosity
of its head is more raised than usual in the Plesiosauri,

The dentary piece of the lower jaw contains the alveoli of 60
teeth ; the diameter of the base of the large anterior ones in the
expanded symphyseal portion equals frds of an inch. The
length of this dentary piece is 13 inches. The diameter of the
expanded symphysis 4 inches.

In the collection of Miss Philpotts at Lyme Regis there is a
dentary bone which appears to be referrible to this species, but
it is smaller, measuring 13 inches in length and 3 inches across
the expanded symphysis ; it contains the alveoli of 27 — 27 = 54
teeth, of which the six anterior ones on each side are larger
than the rest, and occupy the first four inches of the bone on
each side. The projecting crown of one of these teeth measured

1 inch 3 lines, and the breadth of its base 5| lines.

A femur, supposed to belong to the same P/eslosaurus, mea-
sured 12 inches in length, and 6 in breadth at the distal end :
its anterior margin was slightly concave ; the shaft smooth, and
the extremities longitudinally striated : near the proximal end
{2~ inches below it) there is an oval muscular surface, measuring

2 inches by 1 inch.

Localities, — The remains of this species which I have exa-

BRITISH FOSSIL REPTILES. 77

mined are from the lias of Street and the neighbourhood of Bath ^
also from the lias of Bitton, in Gloucestershire ; and from that
of Charlton, two miles from Cheltenham. I have not yet ob-
served specimens from the lias of Whitby.

None of the Plesiosaurian vertebrae of the Wirtemberg lias
bone-beds can be referred to the present species.

I have next to notice some vertebrae of a Plesiosaurus contained
in the Museum of the Philosophical Institution at Bristol, which
approximate to the character of the last-described species in
the prominence of the costal articular surfaces, but which differ
in the shape of the body in so marked a degree as to render in-
admissible the idea of their specific identity. In the PL arciia-
tiis the contour of the articular surface is nearly circular, with
a narrow superior emargination corresponding with the canal
for the spinal marrow : in the present species the contour of
the same part approaches to the triangular form from the flat-
ness and upward convergence of the upper moiety of the sides
of the body.

The anterior and posterior- articular surfaces are flatter, but
exhibit a slight middle convexity.

The inferior surface is traversed by a broad longitudinal
elevation, on each side of which is the typical foramen. From
the median ridge the surface of the vertebra extends in a slight
concave curve to the base of the transverse process, the antero-
posterior extent of which equals one half of that of the centrum
itself.

The base of the neurapophyses is bounded by a gentle convex
line, and the extent of surface intervening between it and the
costal articular surface exceeds by one half the vertical diameter
of that surface.

The upper part of the neurapophyses, and their spine, were
broken off in the vertebrae examined by me, the only ones of
this species which I have as yet seen.

The length of the body of the cervical vertebrae here Inches.

described is 3^

Its transverse diameter, including transverse processes 4|-
Its vertical diameter '6^

Localities. — The vertebrae here described are from the lias of
Weston, near Bath*.

* In Professor Sedgwick's collection at Cambridge there is a cervical verte-
bra oi a. Plesiosaurus, measuring two inches and a half in transverse diameter,
having the neurapophyses anchylosed to the centrum, and the ribs to the

78 REPORT— 1S39.

Flesiosaurus trigonus, Cuv. (?)

This species was founded by Cuvier on a vertebra from the
coast of Calvador, which presented a triangular form, like some
of those of the Mosasaurus, i. e., it was flat and broad below,
and graduall}'^ decreasing above ; on the sides of the lower sur-
face were transverse processes. As the form of the articular
surfaces are not described, it may be questioned whether the
vertebra above alluded to really belongs to the Plesiosaurian
type : and in the present instance these surfaces deviate some-
what from the characteristic form.

They are flat on the outer or peripheral third, and the re-
maining central part, instead of being convex, as in the Plesio-
sauri generally, are slightly concave. It is this character, in
addition to their smaller size, which pi'incipally distinguishes
the present from the last-described vertebra, with which it other-
wise closely agrees in its leading characters, viz. those afforded
by the development and position of the transverse processes.
These transverse processes are short and thick ; the breadth or
antero-posterior diameter of their base equals one half of that of
the entire centrum ; they are directed obliquely downwards.

The contour of the articular surface of the body of the verte-
brae is nearly circular : the triangular figure is due to the posi-
tion and direction of the transverse processes ; the distance be-
tween these and the neurapophyses equals twice their vertical
diameter : and although this character will be lost in the more
posterior cervical vertebrae, it is to be remembered that it is one
which has never presented itself in those Plesiosauri of which
the entire series of cervical vertebrae have been examined.

Inches.
The antero-posterior extent of the vertebra described is If
Transverse diameter, including the transverse processes 2\
Vertical diameter of the body 2

This vertebra is from the lias of the bone-bed of the Aust
Cliff, near Bristol.

Plesiosaurus hrachyspondyluSy O.

— recentior ( ? ), Conybeare*.

giganteus ( ? ) Ibid.f

transverse processes, which are as remote from the neurapophyses as in the
PL subtrigoiDis ; bnt the form of the articular surface of the vertebral centre is
more regularly rounded. This vertebra, which seems to indicate a new species
or subgenus of Enaliosaurs, is from the lias at Bridport, Dorsetshire. It is re-
commended that the Saurian fossils of this locality be carefully searched for and
preserved.

* I-Ierm. Von Meyer, PalcBologka, p. 112. f Geol. Trans., 1824, p. 389.

BRITISH FOSSIL REPTILES. 7"

In the museum of Viscount Cole, at Florence Court, there
are some detached vertebral centres, which, from their remark-
able compression in the antero-posterior direction, resemble
those of the Ichthyosaurus, but which combine the peculiar
Plesiosaurian structure with this character.

The articular surfaces for the contiguous vertebrae are very
slightly concave, with a small round depression, but no convex
rising at the centre. The sides and under part of the body are
concave : the surface is tolerably smooth, and the two usual
vascular perforations are present at the lower part of the body.
I have figured one of these vertebrae from the posterior part of
the cervical series, where the costal articular surface is continu-
ous with the neurapophysial one, but has not wholly risen above
the centrum.

The costal surface stands out a short way from the level of the
lateral surface of the vertebra in the form of a compressed ver-
tically elongated transverse process.

The neurapophysial depression is shallow, occupies the whole
breadth of the vertebra, and presents a convex edge next the
spinal canal.

The part of this canal due to the centrum is in the form of a
cojicave depression widened at both ends, but more so posteriorly.

Localities. — The vertebrae here described were from the Kim-
meridge clay, Heddington Pits, near Oxford.

There are similar vertebrae in the collection of the Philoso-
phical Society of Bristol, from the Kimmeridge clay near Wey-
mouth. These appear to be the vertebrae figured by Mr. Cony-
beare in PI. XXII. vol. i. Second Series of the Geol. Trans.,
also from the Kimmeridge clay near Weymouth, belonging to the
same species. They present the same compressed form and cen-
tral pit on the anterior and posterior articular surfaces, and pro-
minent costal articular surfaces. These figures are referred to by
Cuvier and V. Meyer as the type of the Flesiosaurus recentior
of Conybeare. They are alluded to by Mr. Conybeare in a
subsequent memoir as belonging to the same species as the
gigantic fragments obtained by Professor Buckland at Market
Raisen, and which are provisionally indicated under the name of
giganteus. The most striking peculiarity of this species is, that
the anterior cervical vertebrae are even more compressed in the
antero-posterior direction than the posterior cervical vertebra
above described, while the vertebrae in the dorsal region regain
more of the ordinary Plesiosaurian proportions, although still
narrower in the antero-posterior direction than in any of the
previously described species ; hence we may conclude that the
neck was shorter in the PI. hracht/sjmiulyhis than in the other

80 iiEPORT~1839.

Plesiosauri, and it may be inferred that it had a large and heavy
head.

As there are other species of Plesiosailrus from strata as re-
cent as those which contain the remains of the present^ and as
there are at least two species of Plesiosaiiri of gigantic propor-
tions, one of which has the humerus and femur of the ordinary
conformation, while the other has the same bones distinguislied
by large trochanterian processes, the aim which I have in view
to indicate as precisely as possible the different species of Ple-
siosaui'iis that have characterized our strata, seemed to be best
answered by giving a name to the present species indicative of
a structure which appears to be peculiar to it.

Plesiosaurus costatus.

Under this name I provisionally indicate a species character-
ized by a well-marked vertebra from the bone- bed of the lias at
Aust Cliff, near Bristol.

In its general form and proportions, this vertebra (which is
is one of the anterior or middle cervicals) comes nearest to the
corresponding vertebra of the Plesiosaurus macrocephalus, and
presents a still more important character of agreement in the
contiguity of the costal and neurapophysial articular depressions.
I have already observed that the costal surfaces rise a little
above the level of the vertebra in the Plesiosaurus macrocepha-
lus : in the present specimens they are supported on two
distinctly developed articular processes, the intervening groove
of which is deeper and broader than in the Plesiosauri gene-
rally. The size of the two costal surfaces combined indicates
the hatchet- shaped rib to have been relatively larger than usual.
The free surface of the vertebra is more irregular than in the
PL macrocejjhalus ; it is marked in a characteristic manner by
irregular ridges near the raised circumference of the anterior
and posterior articular surfaces, from which rugged boundaries
deep and pretty broad grooves pass in a nearly parallel direction
towards the middle of the vertebra. The lower surface is tra-
versed by a strongly developed median longitudinal ridge, on
each side of which is the large characteristic vascular foramen.
The articular surface on the anterior and posterior sides of the
body deviates from the typical Plesiosaurian character in being
more concave in the centre than at the circumference, instead of
the reverse condition. About one fifth part of the articular sur-
face next the periphery is flat. The remaining median con-
cavity is slightly marked.

The articular base of the neurapophysis is triangular, and the
two sides converge downwards at a more acute angle than I have

BRITISH FOSSIL REPTILES. 81

observed in the corresponding part of any other Plesiosaur.
The distance from the upper margin of the posterior oblique
process to the inferior apex of the neurapophysis exceeds the
vertical diameter of the body, and is double the extent of that
part of the centrum below the neurapophysis. The articular
base of the neurapophysis extends inwards above the centrum,
so as to form part of the floor of the spinal canal : the inner
surface of the neurapophysis is traversed by a longitudinal ridge.

The spine of the vertebrae here described was unfortunately
broken off.

I have not met with any other example of a Plesiosaurian
vertebra agreeing with the one above described, except a few
from the Bristol lias above specified.

Among these is a centrum of the dorsal series of vertebrae,
which, from the character of the anterior and posterior articular
surfaces, and the rugose lateral and inferior surfaces, belongs,
in all probability, to the same species. It is relatively more
compressed in its general form : but we may observe the same
difference between the cervical and dorsal vertebrae of the PL
dolichodeinis.

Admeasurements of the above-described Cervical Vertebra.

Inches. Lines.
Antero-posterior diameter of the body . . 1 6
Transverse diameter of the body .... 2

Vertical diameter 1 9

Dorsal Vertebra.

Antero-posterior diameter of body .... 1 6

Transverse diameter 2 9

Vertical diameter 2 6

Plesiosaurus daedicomus* .

Of this well-marked species the humerus is preserved in the
collection of Sir Philip Egerton : the specific name relates to
the peculiar form of that bone, which resembles a flattened
spoon in the narrowness of the shank or shaft, and the remark-
able expanse of the distal extremity. The breadth of this part
equals one half of the entire length of the bone, and is five times
greater than the breadth of the proximal extremity. The shaft
gradually expands from the proximal end, and exhibits the flat-
tened form characteristic of the genus. There is no trace of a
tuberosity at the proximal extremity.

* So/3y|, a spoon ; ufcof, humerus, or arm-bone.
voL.viir. 1839. g

82 REPORT — 1839.

From the analogy of otlier Plesiosauri I should conceive the
femur to have corresponded with the humerus in the peculiar
form above described ; but as yet I have not met with an ex-
ample of this bone.

Localities. — This bone was from the Kimmeridge clay at
Shotover, near Oxford.

In the collection of Professor Sedgwick, at Cambridge, there
is an imperfect gigantic paddle, of which the first bone (whether
humerus or femur is not determinable in its detached condition,)
presents an expansion of the distal extremity hardly less dispro-
portionate than that above described : the length of this bone is
sixteen inches, the breadth of the distal extremity is eleven
inches. There are ten of the smaller bones of the paddle asso-
ciated with the above, and presenting the Plesiosaurian type,
but without modifications worthy of being specified. The spe-
cimen was discovered by Captain Smith in the Oxford clay
near Bedford.

Plesiosaurus rugosus.

In three museums, viz. that of Bristol, of York, and of Vis-
count Cole, I have observed Plesiosaurian vertebrae which are
readily distinguishable from all other vertebrae by the peculiarly
rugous character of the free or non-articular surfaces of the
body. But this superficial modification is not the only cha-
racter by which these vertebrae may be distinguished.

The most characteristic vertebrae, viz. those from the middle
of the cervical region, although they present modifications of
the neurapophyses and costal articular surfaces resembling
those characteristics of the PL Hawkinsii more nearly than
any other species, yet differ therefrom in the following parti-
culars. The two costal impressions on each side are com-
pletely divided, and by a wider and a deeper groove : they are
situated nearer the lower margin of the vertebra ; and an extent
of surface equal to twice the vertical diameter of the combined
surfaces intervenes between them and the base of the neurapo-
physis. This is bounded by a more open angle than in the
PL Hawkinsii. The distance from the lower margin of the
neurapophysis to the articular surface of the posterior oblique
process, is only a little more than half the extent of the centrum
below the neurapophysis, a proportion which I have not yet
met with in any other species, but to which the vertebrae in
the PL Haivkiiisii offer the nearest approach.

The contour of the articular surface of the vertebral body is
almost circular : the peripheral border of this surface is convex,
which leads inwards to a concavity, and the centre of the sur-
face again rises in a slightly convex form.

BRITISH FOSSIL REPTILES. 83

The bodies of the vertebrae are relatively longer than in the
PL Hawkinsii, being intermediate in this respect between it
and the PI. dolichodeirus .

Localities. — ^The vertebras of this species occur in the lias at
Lyme Regis, in that of the Aust Cliff, Bristol, and in the
neighbourhood of Whitby.

Plesiosaurus grandis.

From the greensand, Kimmeridge clay, and Oxford clay,
many specimens have been obtained of humeri or femora,
closely corresponding with the Plesiosaurian type of these
bones, but of gigantic size, and belonging to two distinct spe-
cies of Enaliosaurian reptiles.

The long bone (humerus or femur) indicative of the first of
these species, presents the ordinary rough, elliptical, slightly
convex head, beneath which the bone slightly contracts to
about one third of the distance from the opposite end ; it then
begins gradually to expand in breadth, and to decrease in
thickness to the distal extremity, which is terminated by a
pretty regular semicircular contour. The anterior margin is
slightly concave ; the posterior one more concave. Beneath
the head or proximal end of the bone there is a rough surface
for muscular attachment, but no process or trochanterian pro-
minence. The length of one of these bones in the collection of
Viscount Cole is sixteen and a half inches. The breadth of the
narrowest part of the bone is three inches and two thirds, that of
the broadest part eight inches. The surface of the upper third of
the bone is roughened with small perforations and longitudinal
ridges ; the surface of the lower two thirds is smooth, except
near the articular expanded extremity, which is pitted with
small vascular grooves.

A second long bone in the same collection, having similar
characters to the preceding, measures fourteen inches in length,
seven inches in breadth across the distal extremity, and nine
inches in girth round the middle of the bone : this is probably
the humerus.

A third long bone, also in the collection of Viscount Cole
and from the Kimmeridge clay at Shotover, belonging to the
same species as the preceding bones, measures seventeen inches
and a half in length, seven inches and one third across the
distal end, and nine inches in girth. The contour of the distal
articular end is rounded as in the first-described bone, and it is
probable that they are both femora ; but as the proportions of
the humerus and femur are not constant in the genus Plesio-
saurus, the nature of the above-described bones cannot be

G 2

84 REPORT— 1839.

certainly determined until some perfect specimens are met
with.

From the same member of the upper oolite system, and from
the same locality, Shotover, Lord Cole possesses a well-pre-
served large triradiate flattened bone, which, from its corre-
spondence in colour and grain with the humeri and femora
above described, seems unquestionably to belong to the same
species of Plesiosaurus, of which it represents the scapulo-
clavicular bone.

The longest diameter of this bonr, viz. from the end of the
ray representing the scapula to the sternal end of the clavicle,
is nine inches. The breadth of the scapular ray is three and
a half inches ; both this ray and the one representing the ster-
nal end of the clavicle are much flattened, not exceeding half
an inch in thickness : the third ray, which represents the hu-
meral end of the scapula and clavicle, is short and thick, and
terminates in a rough convex articular surface, part of which
joins the coracoid, and the rest contributes to form the glenoid
cavity for the humerus. The external and internal surfaces of
this bone are pretty smooth, but exhibit the lines or striae of
growth, which radiate from the centre of the bone.

Near the place where the above- described bones were de-
posited, there was also found an ischium so closely corre-
sponding with them in size, colour, surface, and general con-
dition, as to leave little doubt of their being parts of the same
species if not individual. The length of this bone, taken be-
tween the two extremities of its median margin, is twelve
inches ; the distance from the anterior of these margins to the
anterior edge of the acetabular surface four inches. As this
bone confirms the indications of the specific difference of the
Plesiosaurus under consideration, a few words as to its modifi-
cations in other species may here be useful. The median mar-
gin of the ischium in the PL Hawkinsii, e. g., is straight, and
is joined to that of the opposite bone, except at the angles,
which are rounded off.

in the PL dolichodeirus only the upper half of the corre-
sponding margins of the ischia are sufficiently straight and pa-
rallel to be in contact ; the lower half of the median margin of
each bone receding from its fall in a gentle convex line.

In the PL brachycephalus the whole contour of the median
margin of the ischium is convex, but least prominent at the
middle part. In the present large species the corresponding
margin is still more convex, so that it could only come in con-
tact with the opposite ischium at one point of this margin.

The anterior concavity, which cooperates with the pubis in

BRITISH FOSSIL REPTILES. 85

the formation of the foramen ovale, is relatively shorter than in
the ischia of any of the preceding species ; and the neck of the
bone, or that end or angle which enters into the formation of
the acetabular cavity, is relatively shorter and broader. The
corresponding part of the scapulo-clavicular bone, vrhich cor-
responds with the ischium, presents the same distinctive cha-
racter. The acetabular surface is rough, convex, and with a
ridge along the middle of its long axis.

Plesiosaurus trochanterius.

The long bones of the second gigantic Plesiosauroid species,
from the Kimmeridge clay, deviate from the usual structure of
the humerus and femur in that genus in having a strongly-
developed trochanterian ridge projecting from the outer side of
the head of the bone : this process is of considerable breadth,
stands well out from the surface at its upper part, then gradu-
ally subsides, and is lost in the upper third of the humerus.
The shaft of the bone is more cylindrical than in most of the
Plesiosauri, and the distal expanded extremity is of less rela-
tive breadth. The whole surface of the bone is roughened by
longitudinal furrows, ridges and foramina; and on the inner
side of the bone, about one fourth of the length of the bone
from its head, there is a transversely elongated very rough sur-
face for the implantation of muscle.

One of these long bones in the museum of Viscount Cole mea-
sures two feet in length, nineteen inches in circumference at the
head, including the trochanter, twelve inches and a half round
the middle of the shaft, and ten inches across the flattened
distal end ; this is terminated by two slightly concave equal
articular surfaces, which meet at a ridge or salient angle. The
thickness of these surfaces is one inch nine lines ; they are
each traversed longitudinally by a convex ridge, the base of
which is rather more than two thirds the breadth of the arti-
cular surface, which is slightly concave on each side of the
median ridge.

Locality. — This bone is from the Kimmeridge clay of Shot-
over Hill. The trochanter here rises as high as the head
itself, from which it is separated by a deep and narrow
groove.

Professor Sedgwick possesses a humerus or femur of this
species, from the brown alluvial clay at Bourn, Cambridge, pre-
senting a single long external trochanter, from which the bone
suddenly tapers to the shaft, and then becomes flattened and
expanded.

86 REPORT— 1839.

Foot. Inches.

Length ......... 1 4

Breadth of distal extremity ... 9
middle of shaft ... 4

The proximal surface is pitted like the epiphysial end of a
mammiferous femur : it was probably capped by cartilage, and
joined by ligamentous substance, without a synovial joint, to
the acetabulum.

Plesiosaiirus affinis.

In the excellent collection of fossil remains in the museum of
Viscount Cole there is a humerus or femur similar to that of
the preceding species in regard to the existence of a trochanter,
but differing in its smaller development, in the general form of
the shaft of the bone, and in size : this bone is only eight
inches in length.

The trochanter projects from the outer side of the head of the
bone, but its most prominent part is on a level with the inferior
margin of the head or proximal articular surface. The breadth
of the trochanter is rather more than one third the breadth of
the proximal extremity. The trochanter gradually subsides to
the level of the shaft, which in the upper fourth of its extent
presents with the trochanter a triedral transverse section with
the angles rounded off. The shaft begins to be flattened imme-
diately below the trochanter, and gradually to increase in breadth,
but it preserves a greater relative thickness than in the larger
bone. The general surface is broken by fine striae and perfora-
tions, and there is a well-marked transversely oblong rugosity
on the inner side of the upper fourth of the bone.

The differences just specified between this small trochanterian
bone and the great one before described show that it cannot have
belonged to a younger specimen of the same species. Both bones
are solid throughout.

Locality. — Kimmeridge clay, Heddington-pits, Oxford.

CHARACTERS OF THE GENUS ICHTHYOSAURUS.

The Enaliosaurians of the present family differ from those of
the preceding most remarkably in the shortness of the neck and
the equality of the width of the occiput with that of the thorax,
which almost immediately succeeds it ; impressing the observer
with the conviction that the recent animal must have resembled
a Cetacean or a Fish in the total absence of any cervical con-
striction.

This close approximation in the Ichthyosauri to the form of
the most strictly aquatic animals of the existing creation is ac-

BRITISH FOSSIL REPTILES. 8/

companied by an important modification of the articular surfaces
of the vertebral centres, each of which surfaces presents a well-
marked concavity, leading to the inference that they were ori-
ginally connected together by an elastic capsule filled with a
fluid, as in the vertebral joints of the back-bone of Fishes, and
the Perennibranchiate or most fish-like of the Reptilia.

The structure of the fins of many species oi Ichthyosaurus de-
viates from that of the Cetacean paddles, and approaches in cer-
tain peculiarities more closely to that of the fins of Fishes, than
has yet been found in any other reptile. First, the digits exceed
the typical number _five, and resemble in their numerous and
small constituent phalanges the jointed rays which support the
natatory membrane of the pectoral and ventral fins of true
Fishes ; and, secondly, numerous cartilaginous bifurcate rays
were added to the bony apparatus which supports the tegumen-
tary expansion.

With these important modifications of the head, trunk, and
extremities in immediate relation to aquatic progression, the law
of the correlations of organic structure would lead us to antici-
pate some corresponding modification of the tail. Accordingly
we find the vertebrae of this part to be much more numerous
than in the previously-described Enaliosaurian group. There
is no trace, however, of any confluence of the terminal caudal
vertebrae, or of any modification of their elongated neur- and
hffim-apophysial spines, such as form the characteristic struc-
ture supporting the tail of the osseous Fishes. The numerous
caudal vertebrae gradually decrease in size to the end of the tail,
where they assume a compressed form ; and thus the tail, in-
stead of being short and broad as in Fishes, is lengthened out
as in the Crocodiles.

The very frequent occurrence of a fracture of the tail about
one fourth of the way from its distal extremity, had led me to
suspect it to have been connected with the presence of a tegu-
mentary caudal fin ; and the laterally compressed form of the
terminal vertebrae, since ascertained by Sir Philip Grey Egerton,
gives additional demonstration both of the existence and direc-
tion of such a fin. The only evidence, in fact, which the skele-
ton of the Cetaceous mammal aff'ords of the powerful horizontal
caudal fin which characterizes the recent animal is the depressed
or horizontally flattened form of the terminal vertebrae. We
may infer, therefore, from the corresponding vertebrae of the
Ichthyosaurus being flattened in the vertical direction, or from
side to side, that it possessed a caudal tegumentary fin expanded
in the vertical direction ; and it would be highly advisable to
examine narrowly the lias matrix in which the tail of the Ich-

88 REPORT — 1839.

thyosaur may have been imbedded for traces of carbonaceousi
discoloration, or of an impression of this fin, from which some
idea might be formed of its shape and size*.

Thus in the construction of the principal natatory organ of
the Ichthyosaurus we may trace, as in other parts of its struc-
ture, a combination of Mammalian, Saurian, and Ichthyic pe-
culiarities. In its great length and its gradual diminution we
perceive the Saurian character; its tegumentary nature, un-
supported by osseous rays, bespeaks its afl&nity to the Cetaceans ;
while its vertical position brings it close to the peculiar condi-
tion of the natatory organ in the Fish.

But, it may be argued, the horizontality of the caudal fin of
the Cetacea is essentially connected with their exigencies as
breathers of the atmospheric air : without this means of dis-
placing a mass of water in the vertical direction, the head of the
whale could not have been brought with the required rapidity
and facility to the surface to inspire ; and as the Ichthyosaurus
was also an air-breather, a like position of the caudal fin might
be considered to be equally essential to its existence in the
water.

To this objection it may be replied that the Ichthyosaurus, not
being warm-blooded, would not need to bring its head to the
surface so frequently, or perhaps so rapidly, as the Cetacean ;
and, moreover, a compensation for the absence of a horizontal
terminal fin is provided in the presence of the two posterior
extremities, which are modified as paddles, and which are wholly
deficient in the Cetacea.

Thus I conceive that the living Ichthyosaurus must have pre-
sented the general external figure of a huge predatory abdominal
fish, with a longer tail and smaller caudal fin than usual ; scale-
less moreover, and covered, according to the minute and careful
observations of Dr. Buckland, with a smooth or finely- wrinkled
skin analogous to that of the Cetacea.

A closer inspection of the enduring parts of these singular
inhabitants of the ancient deep, shows that under their fish-like
exterior was concealed an orgp-nization which, in the main, is a
modification of the Saurian type.

Of the Cranium. — The general form of the cranium resem-
bles that of the dolphin, but it differs in the comparatively

* I would more particularly recommend tWs observation to be made on spe-
cimens oi Ichthyosaurus from the lias of Barrow-on-Soar, whicb appears to have
been more favourable for the preservation of the soft integument than in other
localities. The specimen from which Dr. Buckland described the tegument of
the abdomen, and that in which the tegument of the fin and the soft rays were
described by uie, were both from Barrow-on-Soar.

BRITISH FOSSIL REPTILES. 89

feeble development of the cerebral cavity, and still more essen-
tially in the unanchylosed state of the composite cranial bones,
— a fact already referred to in the general characters of the
Enaliosauria. We shall see, moreover, that the connexions
of the bones partake more of the Lacertian than of the Croco-
dilian types ; but the Ichthyosaurus departs at once from both
the Cetacean and Saurian characters in the disproportionate de-
velopment of the intermaxillary, as compared with the max-
illary bones, and in the immense size of the orbits and the large
and numerous sclerotic plates : it is these modifications vrhich
give to the cranium of the Ichthyosaurus its peculiar features.
The occipital bone presents in a separate state the usual ele-
mentary pieces, called the basi- ex- and supra-occipital bones.

In tracing the analogies of this composite bone, we first
observe that in the Crocodile the basi-occipital terminates be-
hind in a convex hemispheric tubercle, which articulates with
the wide adontoid appendage of the axis, and with the small
body of the atlas. Above the occipital tubercle there is a con-
cave surface on which rests the medulla oblongata. The ex-
occipitals articulate with the lateral boundaries of this surface,
and form no part of the tubercle for articulation v/ith the atlas.
In the Lacertians the ex-occipitals encroach considerably upon
the upper surface of the basi-occipital, diminishing the extent
which it affords for the support of the brain, and entering largely
into the formation of the articular tubercle by which the head is
joined to the vertebral column.

In the Ichthyosaurus the ex-occipitals articulate to the whole
of the upper surface of the basi-occipital, which sends up a
compressed conical crest between them. The ex-occipitals also
form a portion of the vertebral articular tubercle, but in a less
degree than in most Lacertians. In this respect the Ichthyo-
saurus holds an intermediate position between the Crocodilian
and Lacertian Saurians.

The restorations of the posterior region of the Ichthyosaurian
cranium hitherto given* are defective in regard to the relative
positions of the ex-occipitals to the basi-occipitals ; but the re-
presentation by Mr. Hawkins f approaches the closest to nature.
The under part of the basi-occipital expands and terminates
anteriorly in a pretty regular curve, with the convexity directed
forwards. There is in some species a slight emargination in the
middle of this curvature entering into the formation of the cir-
cumference of the Eustachian outlet of the basi-sphenoid.
The articidar tubercle of the basi-occipital frequently presents

* Geol. Trans., 1822, p. 117. f Memoirs on Ichthyosauri, fol. PJ. I.

90 REPORT — 1839.

near its middle a vertical depression, as if for the insertion of
some ligament.

I may here observe that in true Fishes the concave articular
surface is present on the body of the posterior cranial verte-
bra, or occiput, as it is on the bodies of the ordinary vertebrae.
The deviation from this character in the Ichthyosaurus, and the
substitution of a diametrically contrary structure, bespeaks
strongly its true Saurian nature. In the Cetacea the basi-occi-
pital forms no part of the articulation with the vertebral column,
but the head is joined to the atlas by two ex-occipital condyles
as in other Mammalia.

The ex-occipital s are proportionally smaller in the Ichthyo-
sauri than in the Crocodiles, and do not unite together so as
to complete the boundary of the foramen magnum above, but
allow the supra-occipital element to form about one third of the
upper circumference of this foramen. This approximation to the
Lacertian type, of which the discerning eye of Mr. Conybeare*
had led him to entertain a suspicion from mutilated specimens,
I have ascertained beyond doubt to be a generic structure in the
Ichthyosauri.

Two very strong mastoid bones extend from the ex-occipitals
towards the articular extremity of the tympanic bone, and nearly
obliterate the space intervening at the back part of the skull
between the parietal bifurcations and the occipital bone.

The solid structure of the back part of the cranium which thus
ensues gives to the skull of the Ichthyosaurus a strong resem-
blance to that of the Crocodile ; but as this is an adaptive rather
than a typical conformation, it affords but a slender argument
for their affinity. The development of the occipital bones in
both cases depends on the necessity for a due extent of surface
for the implantation of the powerful nuchal muscles which must
have mainly wielded a head produced anteriorly into long and
heavy jaws beset with numerous and formidable teeth.

The upper part of the cranium includes the parietals, the
composite frontals, and the principal elements of the temporal
bones.

The parietals form together a strong triradiate bone, as in the
Plesiosaurs. The temporal muscles, which derive part of their
origin from its median and anterior portion, extend to the middle
line, where they are separated by an osseous intermuscular crest.
Anterior to this crest, close to or in the coronal suture, the pa-
rietal is perforated, — a structure not present in the Crocodiles,
but peculiarly characteristic of the Lacertian Saurians, and the

* Geol. Trans., 1822, p. 117.

BRITISH FOSSIL REPTILES. 91

more important as an indication of affinity, because it is not an
adaptive character. The two posterior and symmetrical pro-
cesses of the parietal extend outwards to abut against the tym-
panic and squamous bones, and give additional strength to the
point of resistance against which the lower jaw works.

TJie inner surface of the median parietals is not, as might
have been anticipated, in immediate contact with the cerebral
membranes, but rests upon a symmetrical median single plate of
bone of a subquadrate form, with the posterior angles thickened
and supporting two surfaces which articulate more immediately
with the superincumbent parietals. The internal superficies is
concave, the external convex with two vascular foramina in the
same transverse line. This bone I take to be the interparietal,
overlapped by the ordinary lateral parietals, which are anchylosed
together.

The temporal aperture is circumscribed by the jugal, zygo-
matic, and tympanic bones, and is reduced to much smaller
dimensions than in the Lacertians, owing in part to the greater
breadth of the zygomatic element of the temporal. In the
Marine Tortoises the whole of the temporal aperture is con-
cealed by a continuous ossification extended from the pa-
rietals and posterior frontals to the zygomatic arch.

In the Crocodiles we find a part of this structure still remain-
ing in the osseous bridge which traverses longitudinally the
temporal fossa between the parietal and the posterior frontal
bones.

In the Lacertians and Plesiosaurs the temporal fossa is single
on each side, but in the Ichthyosaurus we find a transitional
structure in the occurrence of a second distinct fossa in the
temporal region left between the zygomatic and tympanic
bones.

In the general position and strong and immoveable condition
of the principal bones forming the pedicle for the articulation of
the lower jaw, there occurs, as might be expected, a deviation
from the Lacertian type, and a similarity to that higher Saurian
family, in which there is a similarly ponderous and well-armed
lower jaw.

The tympanic or articular bone, instead of being attached only
by its upper extremity to the conjoined squamous and mastoid
elements of the temporal, is in the Ichthyosaur wedged in be-
tween the mastoid, squamous, and zygomatic elements, and is
further established in this position by the irregularly dentate
structure of the sutures.

This bone, moreover, presents an unusual degree of solidity
and robustness in all the species of Ichthyosaurus. It thus

92 REPORT— 1839.

affords a strong and unyielding point of resistance for the move-
ments of the lower jaw, — an adaptation which the size, arma-
ture, and violent uses of that jaw in predatory attacks rendered
indispensable. And as a similar structure and office of the lower
jaw of the Crocodile is the condition of a corresponding strength
and fixation of its articular pedicle, so in this part of the cranial
structure we find that the Ichthyosaurus resembles the Croco-
dilian and differs from the Lacertian types of structure.

There is still another peculiarity of the articular pedicle of the
lower jaw of the Ichthyosaurus, for the intelligibility of which
it will be necessary to premise some observations on the struc-
ture of the same part in the existing oviparous Vertehrata.

Commencing with the structure of the articular pedicle of the
lower jaw in the bird, we shall find that the tympanic bone is
connected with the upper jaw by two osseous columns, of which
the lower one abuts against the palatal bones, while the second
and superior extends to the lower angle of the superior maxillary
bone. It is by means of these two columns that the movements
of the articular pedicle are communicated to the upper man-
dible.

It is with the upper of these osseous columns, which relates
to the Ichthyosaurian structure under consideration, that we are
at present concerned. Its usual appearance is that of a simple
osseous style, and it is described by Cuvier and other compara-
tive anatomists as the analogue of the jugal bone. If, however,
the state of this apparently simple style be looked into in the
embryo bird, it will be found to consist of two distinct parts, —
that ossification commences by two distinct centres. In the
Ostrich, indeed, which is one of the most reptilian of birds, the
two bones remain distinct to nearly the period of full growth.

The anterior of these I regard as the true os jugale j the
posterior as the homologue of the os zygomaticum, otherwise
entirely wanting in the skull of the bird.

Now here the important point gained in tracing the homolo-
gies of the lateral bones of the skull through the Saurian group
is the evidence of the separate existence of the squamous and
zygomatic elements of the temporal bone in the same cranium.
In the Lacertians the zygomatic, squamous and jugal bones are
always distinct ; but the zygomatic style extends to the proxi-
mal instead of to the distal end of the os tympanicum as in
Birds. Its position, parallel with the malar bone, is the same
however as in Birds; and, as in that class, the anterior ex-
tremity of the zygomatic bone is joined to the malar bone, and
is directly continued from it.

In the Crocodilians the position of the os zygomaticum is

BRITISH FOSSIL REPTILES. 93

altered ; its anterior extremity abuts against, and is confluent
with the squamous element of the temporal bone, whilst its op-
posite extremity is wedged in between the tympanic and the
jugal bones ; the whole of the posterior margin of the os tym-
panicum moreover runs parallel with, and is firmly united to
the OS tympanicum.

In the Ichthyosaurus the os zygomaticum is present as a se-
parate bone, and resembles in its massive proportions that of
the Crocodile : the anterior extremity is expanded ; of this the
greater part is articulated with the posterior extremity of the
jugal bone, and the remainder with the squamous element of
the temporal. The opposite end of the os zygomaticum abuts,
as in the Bird and Crocodile, against the lower or articular ex-
tremity of the OS tympanicum, but without having the whole of
its posterior margin united with the tympanic bone, as in the
Crocodile; hence results that vacancy which Mr. Conybeare*
has termed the '' lower temporal fossa," and which he describes
as being bounded below by ^' another bone interposed between
the OS quadratum and the jugal," and considered by him '^as
another dismemberment of the temporal." The true homology
of this bone could not be appreciated whilst the squamous ele-
ment of the temporal bone was regarded as including also the
zygomatic, or as a '' squamoso-zygomatic bone" ; but when the
independent origin of the zygomatic bone has been determined,
and its modifications traced through the existing Saurian types,
the precise nature of the dismemberment of the temporal which
plays so conspicuous a part in the articulation of the lower jaw
of the Ichthyosaurus is at once recognisable. In the strength
of the zygomatic bone, and its connection with the articular in-
ferior end of the tympanic we perceive the Crocodilian character,
while in the free circumference of the zygomatic bone we find
them associated with Lacertian peculiarities. The Ichthyosau-
rus thus offers a beautiful transitional structure between the
two great existing modifications of the Saurian types which we
should in vain look for elsewhere.

The peculiarly large orbital cavity in the Ichthyosaurus in-
cludes in its circumference six distinct bones : above, the ante-
rior, median and posterior frontals ; in front, the large lachry-
mal bone; below and behind, the jugal and apparently a dis-
tinct and peculiar posterior bone.

In the separation and relative position of the median and an-
terior and posterior frontals the cranium of the Ichthyosaurus
accords with the usual Saurian characters ; but these bones are

* Additional Notices, p. 114.

94 REPORT — 1839.

relatively larger than in the recent Sauria. This increase
of development of the anterior and posterior frontals is de-
pendent on the large size of the eye and the cavity destined to
contain it.

In the composition of the facial part of the skull and the re-
lative sizes and disposition of the bones forming the nasal cavi-
ties and upper jaw, we have the same beautiful examples of a
transitional structure between the Crocodilian andLacertian types
of structure as have been noticed in other parts of the cranium.
With respect to the nasal apertures the tendency is mainly to-
wards the Lacertian structure, coupled with peculiarities purely
Ichthyosaurian.

In the Monitors for example, the bony external nostrils com-
mence at the upper part of the cranium, at a very slight distance
in front of the orbit ; but they extend to near the anterior point
of the upper jaw, where they are bounded by the turbinated
bones. The rest of their circumference is due to the nasal, in-
termaxillary and superior maxillary bones.

In the Crocodile, as is well known, the nostrils are placed at
the anterior part of the face, and are bounded by the nasal and
intermaxillary bones. In the Ichthyosaurus the nostrils are li-
mited to the position at which they commence in the Monitors,
viz. at a short distance anterior to the orbits ; and nearly the
whole of their posterior circumference is due to the lachrymal
bones, which do not at all enter into the composition of the
external nostrils in the existing Saurians.

The characteristic structure and position of the external nos-
trils in the Ichthyosauri dubiously hinted at by Home, were
afterwards admirably determined by Mr. Conybeare.

The upper maxillary bones are remarkable in the Ichthyosauri
for their small size ; they contain rarely more than the posterior
third part of the dental series of their own side. In the Croco-
diles the superior maxillary bones have a much greater relative
extent, and contain generally three fourths of the dental series.
The relative size of the maxillary bones is still greater in the
Lacertians. It is in Fishes that we find the nearest resem-
blance to the Ichthyosauri m the comparatively insignificant
share which the superior maxillary bones contribute to the
formation of the dentigerous margin of the upper jaw. The in-
termaxillary bones on the other hand present in the Ichthyo-
saurus as peculiar a degree of superior magnitude ; a difference,
however, which does not so much arise from the prolonged form
of the snout, as from the disproportionate shortness of the max-
illary bones.

When we compare for example the jaws of the Ich. tenui-

BRITISH FOSSIL REPTILES. 95

rostris with those of the Gangetic Gharrial, an equal degree of
strength and secure attachment of the teeth seem to result from
the two very different proportions in which the maxillary and
intermaxillary bones are combined together to form the upper
jaw. The prolongation of the snout has evidently no relation
to this difference ; and we are accordingly led to look for some
other explanation of the disproportionate' development of the
intermaxillary bones in the Ichthyosaurus, It appears to me
to give additional proof of the collective tendency of the affini-
ties of the Ichthyosaurus to the Lacertian type of structure.
Its aquatic habits necessitated the peculiar position of the nos-
trils, and their limited extent in that position. But in the La-
certians, in which they extend to the fore part of the head, their
interior boundary is formed by the intermaxillary bones 5 these
bones, therefore, conformably with the laws of organic combi-
nations, are extended backwards in an unusual degree, in the
Ichthyosaurus, to enter into their ordinary relations with the
nasal apertures, which are situated unusually far back in the
head. Before quitting the present subject I may remark that
in the Lacertians the median suture of the intermaxillary bones
is soon obliterated 3 while in the Ichthyosaur it is persistent as
in the Crocodile ; but this is a circumstance of minor import-
ance. The nasal bones in the Ichthyosaur differ from those of
both the Crocodilians and Lacertians in having no connexion
with the maxillary bones.

In considering the conformation of the base of the cranium I
shall proceed in continuation to describe that part which enters
into the structure of the upper jaw, as these have been less ac-
curately described than any other part of the skull.

The intermaxillary bones constitute a considerably greater
extent of the osseous palate than in either the Crocodilians or
Lacertians. They are not perforated as in the Crocodile, but
are simply emarginate on the outer side of the posterior part of
their palatal processes, which form, in connection with a corre-
sponding emargination of the palatal processes of the maxillary
bones, the palatal foramina.

The maxillary bones constitute a comparatively small part of
the bony palate, and are, according to my observations, sepa-
rated widely by the intervening palatal bones and vomer, thus
resembling rather the Lacertian than the Crocodilian type.

The palatal bones are joined together by a median suture,
except where the wedge-shaped anterior extremities of the
pterygoid bones are inserted into their posterior interspace,
the pterygoids, in like manner, being separated from each
other posteriorly by the intervening body of the sphenoid. The

96 REPORT — 1839.

posterior apertures of the nostrils are thus thrown far back, as
in the Crocodiles.

The transverse bones, or external pterygoids, complete the
boundaries of an aperture between the pterygoid and maxillary
bones ; and by abutting against the posterior extremities of the
maxillary bones greatly increase their strength.

It appears to me, from a close inspection of some of the most
complete specimens of this intricate part of the skeleton of
the Ichthyosaurus in different museums, that the posterior
nostrils are not perforated, as in the Crocodile, exclusively in
the pterygoids, but that they occur in the interspace between
the internal pterygoids and the basi-sphenoid, as in the Lacer-
tians. With respect to the sphenoid, however, there is a struc-
ture characteristic of the Crocodiles, or at least not present in
those Lacertian crania which I have had opportunities of exa-
mining, viz. an oblique perforation of the basi-sphenoid for the
passage of the common termination of the Eustachian tubes.
The contour of the basi- sphenoid is heptagonal : the posterior
margin is the broadest, and is articulated by a thick rough sur-
face, with a corresponding margin of the basi-occipital. The
oval petrous bones are articulated to the sides of the sphenoid ;
each of the anterior lateral angles are produced, but not to the
same relative extent as in the Lacertians, in which they extend
as buttresses to the internal pterygoids : a moderately long
median slender pointed process is continued forwards from the
middle of the anterior surface of the sphenoid. The superior
or cranial surface of the sphenoid is traversed by a transverse
ridge.

With reference to the lower jaw, it would be superfluous to
offer any observations after the admirable and accurate exposi-
tion of its composite structure which has been given in the
works of Conybeare, Cuvier, and Buckland. I shall therefore
limit myself to a comparison of its leading features with the pe-
culiarities of the two great divisions of the existing Saurian s.

The dentary piece resembles that of the Lacertians and
differs from that of the Crocodilians in being pierced externally
by a few large vascular foramina disposed in a regular series.
It differs also from the Crocodilian type in terminating poste-
riorly above instead of beneath the anterior extremity of the
sur-angular piece. In the degree of development of the coro-
noid or complementary element the lower jaw of the Ichthyo-
saurus holds an intermediate place between the Crocodilian and
Lacertian groups ; it is of greater extent than in the Crocodile,
especially posteriorly, but does not send upwards a well-defined
process^ as in the Lacertians. The process analogous to the

BRITISH FOSSIL REPTILES. 97

coronoid is more developed than in the Crocodiles, but ap-
pertains, as in them, to the surangular element. The jaw of
the recent Crocodilians is characterized bj^ a large vacancy
which occurs between the angular, surangular, and dentarj-^
pieces, while the surangular itself is imperforate. In the La-
certians no vacancy occurs between the above-named maxillary
elements, but in some genera, as the Iguana, the surangular is
perforated. Now, in this highly characteristic deviation from the
Crocodilian structure, we find the Ichthyosaurus participating
with the inferior or Lacertian Saurians ; and in some species, as
the Ich. communis, the surangular bone exhibits a well-marked
perforation. Tt is interesting to observe that in the Teleosaurus
and Steneosaurus the vacuity between the angular and surangu-
lar pieces is reduced to a very small size, which, in combination
with the modification of their vertebral column is evidence of
their transitional character between the great carnivorous Sau-
rians of the past and present epochs. In the backward exten-
sion of the surangular bone the Ichthyosaurus manifests an affi-
nity, not exclusively to the Crocodiles, but to certain Lizards
also, as the large Monitors, in which there is a corresponding
development of the surangular bone in that direction. In the
depth of this piece, on the other hand, the Ichthyosaurus stri-
kingly resembles the Lacertian and deviates from the Crocodilian
type. The conformation of the posterior angle, the robustness
of the articular extremity of the lower jaw, in short, all those
characters that relate to the muscular forces destined to wield an
instrument armed with numerous and large destructive teeth, ap-
proximate the Ichthyosaurian jaw more nearly to the Crocodiles
than to the feeble Lizards ; but in those characters which more
truly indicate affinities to a typical structure, as being less liable
to modification for particular functions, the Ichthyosaurus de-
cidedly manifests its closer affinity to the Lacertian character.

The intermediate or annectent characters of the Ichthyosau-
rus between the Crocodiles and Lizards is exemplified in a re-
markable degree in the modification of that part of both the
upper and lower jaws which is destined for the support of the
teeth.

The Plesiosaurus, like the Crocodile, has its teeth lodged in
distinct sockets : the Lacertian Sauria have their teeth anchy-
losed, like the teeth of most fishes, to the alveolar process of
the jaws, which process is a simple plate corresponding to the
outer wall of the alveoli in the higher Reptiles 3 the inner alveolar
plate being very slightly, if at all, developed. In the Ichthyo-
saurus both the outer and inner plates of the alveolar groove are
present, and the teeth have their bases free, as in the Crocodiles,

1839. H

98 REPORT~1839.

but they are not lodged in distinct sockets formed by the de-
velopment of bony partitions in this groove.

The base of the teeth of the Ichthyosaurus is, however,
covered with a layer of cementum or true bone, which makes
the anchylosis of such pai't to the contiguous jaw quite possible ;
as it is through the medium of a like investment that anchylosis
actually does take place in the existing Lacertians. The pulp
of the tooth of the Ichthyosaurus, after it has been subservient
to the development of the crown of the tooth, becomes solidi-
fied in the fang or base by a coarse ossification which closes the
pulp-cavity at the lower part. Mr. Conybeare, who first pointed
out this fact, at the same time indicated the difference thereby
illustrated between the Tchthyosaur and Crocodile. But the
non-existence of anchylosis of the teeth to the jaw, and the de-
velopment of the inner wall of the alveolar groove, together with
the slight ridges intervening between the teeth, all tend, Mr.
Conybeare observes, to place the Ichthyosaurus much nearer
the Crocodilian than the Lacertian division of the existing Sau-
rians.

Hyoidean Arch. — In three examples of the Ichthyosaurus,
Cuvier* detected the two horns or stylo-hyoid elements of the
hyoidean arch in their natural situation ; and he also states,
that he had seen between, and in advance of these lateral ele-
ments, an osseous disk, broader than long, notched posteriorly,
and which he suspected to be the body of the os hyoides.
These — the only elements of the hyoidean system which are
present in the skeleton of the Ichthyosaurus — are beautifully
displayed in their natural relative position in the Ichthyosaurus
lonchiodon in Mr. Hawkins's second collection, now transferred
to the British Museum.

The cornua are robust, elongated, sub -prismatic bones,
slightly enlarged and truncate at both extremities : their junc-
tion with the small flattened hyoid body seems to have been
by means of abundant flexible ligamentous material : the length
of each cornu is a fifth part the length of the lower jaw.

The condition of the hyoid apparatus is of great weight in
reference to the habits and affinities of the extinct animals in
question ; for in fishes, and the water-breathing reptiles, this
apparatus presents a magnitude and complexity proportionate
to its importance as the foundation of the branchial system.

In the Lacertian Sauria, the os hyoides, though less compli-
cate than in Fishes, presents characteristic modifications in the
number and length of the lateral appendages which relate to

* Ossem. Fossiles, torn. v. part xi., De I'lchthyosaurus, Art. iv., De I'Os
Hyoide.

BRITISH FOSSIL REPTILES. 99

the size and uses of the thick or long, and commonly bifurcate
tongue ; while in the Crocodile the hyoid apparatus is reduced
to the same number of pieces as in the Ichf/u/osaurns, the
body or median plate, however, being cartilaginous, and the
two straight cornua relatively smaller. This simple apparatus
is far less subservient to the support or movement of the
tongue, — which, as Aristotle long ago pointed out, is as little
conspicuous in the Crocodile as in many fishes, — than to the
mechanism for defending the larynx and pharynx from the
entry of water, during the struggles of a submerged prey, when
the mouth of the air-breathing destroyer is necessarily exposed
to the free ingress of the ambient element. The condition of
the hyoid apparatus in the Ichthyosaurus, besides corroborating
the evidence afforded by the rest of the skeleton that this extinct
reptile was an air-breather, indicates that its tongue was almost
as little developed as in the Crocodile ; and since the Ichthyo-
saurus obtained its food at all tunes under the same circum-
stances which necessitate the modification of the hyoid appa-
ratus in the Crocodile, it may be inferred that the hyoid arch
was physiologically related to the working of a similar valvular
apparatus for defending the orifice of its air-tube from the
water admitted into the interspace of the jaws during the cap-
ture and slaughter of its prey ; and the structure and relative
position of the hyoid apparatus corroborates this inference.

Vertebral Column. — In the vertebrae of the Ichthyosaurus are
observed the centrum, the neurapophyses and their spine, the
haemapophyses, and the costal elements. The centrum or ver-
tebral body is characterized, as is well known, by its antero-pos-
terior compression and the concave form of its articular surfaces,
a structure in which the Ichthyosaurus departs from the Crocodi-
lian and Lacertian types of Sauria, and resembles the Perenni-
branchiate Amphibians and Fishes. The body of an Ichthyosau-
rian vertebra might however be distinguished from that of any
fish, by the presence of the neurapophyseal pits on each side of
the shallow canal for the spinal cord ; for the neurapophyses,
though anchylosed above to each other and to their spinous pro-
cesses, always remain detached from the centre below. We can-
not attach much force to the teleological argument founded upon
this structure, or admit its necessity toco-operate with the cupped
form of the intervertebral joints in giving flexibility to the ver-
tebral column, and assisting its vibratory motions necessary in
the mode of progression, which seems to have been common to
the Ichthyosaurus and Fishes ; because in all the osseous fishes
these parts are consolidated with the vertebral centrum as in the
Cetaceans and other Mammals, and yet the vertebral column is
not so locked together as to render impossible such motion of its

H 2

100 REPORT — 1839.

parts as is requisite for swimming. In the separate state of the
neurapophyses in the Ichthyosaurs we perceive a condition
which is essentially Saurian, and one which doubtless would
add somewhat to the facility of inflecting the spine in the ver-
tical directions.

The neurapophyses are interlocked together by means of co-
adapted oblique processes. The hsemapophyses are developed
beneath the abdominal and the caudal vertebrae ; they always
remain distinct from or unanchylosed to the vertebrae above,
and, so far as I have been able to form an opinion, are not
united together below, or to a common spine.

With respect to the structure of the anterior part of the
cervical region of the vertebral column, different views may be
entertained. One theory is as follows : The atlas and axis
resemble each other and the succeeding vertebrae in size and
general form, as is the case in Fishes; but they are anchylosed
together, and the united surfaces are plain, presenting the only
deviation from the characteristic cupped structure recognisable
ill the rest of the vertebral column. Mr. Conybeare obsei*ves,
^' We have only seen the inferior piece or body, if it can be so
called, of the atlas, and the odontoid process (which in all rep-
tiles forms a distinct piece) of the axis : they very nearly re-
semble those of the Turtle." It is not improbable that one or
other of the subvertebral wedge-bones discovered and well de-
scribed by Sir Philip Egerton may here be alluded to ; but Mr.
Conybeare afterwards believed that he had been deceived by a
mutilation of the occipital condyle.

Comparative anatomists are not agreed as to the exact nature
or signification of the odontoid process ; its ossification always
begins by a distinct centre in the Mammalia, in which class it
becomes anchylosed with the body of the axis ; and it is gene-
rally regarded as a peculiar epiphysial appendage to the central
element of the 2nd cervical vertebra. According to this view,
the three subvertebral wedge- bones, which Sir P. Egerton has
so satisfactorily and perseveringly traced out, may be re-
garded as analogous epiphysial appendages of the first three
cervical vertebrae. Or they may be viewed, with the odontoid
process, as haemapophyses or inferior appendages of the verte-
bral centres in a rudimental state ; and the vertebral cup which
receives the occipital tubercle may be deemed, as in fishes, to
be formed by the atlas.

On the other hand, if we look to the Saurians for a clue to
the homologies of the structure in question, we find that the
body of the atlas in both the Crocodilian and Chelonian Rep-
tiles is always remarkably small, and the greater part of the
articular concavity which is adapted to the occipital tubercle is

BRITISH FOSSIL REPTILES. 101

formed by the odontoid epiphysis of the axis, which nearly equals
the body of the same vertebra in size. In the Lacertians, the
body of the atlas is a thin anruilar piece of bone, which forms
merely the circmnference of the articular cup for the occipital
tubercle ; the greater part of which articulates, as in the Croco-
diles and Turtles, with the odontoid epiphysis of the axis. The
consideration of these facts leads to the suggestion of another
hypothesis of the analogies of the anterior vertebrae in the Ich-
tliyosaurus. What has been described as the atlas anchylosed
with the axis, may be the true odontoid process of the axis ex •
hibiting the same excessive development and anterior concavity
adapted to the occiput, as in the Lacertian Sauria. The first sub-
vertebral wedge-bone, according to that view, would then repre-
sent the body of the atlas, as Mr. Conybeare indeed seems to
have regarded it, but reduced to a still more atrophied condition
than in the Crocodile or Turtle. Buthereanother difficulty pre-
sents itself: admitting the first subvertebral bone to be the
atrophied body of the atlas, what then it may be asked are the
second and third subvertebral bones ? I confess that in this, as in
some other of the problems of morphology, I see only a choice of
hypotheses of which none are free from objection. This at least
is certain, that the subvertebral, cervical, wedge-shaped ossicles,
which hitherto have been observed only in the Ichthyosaurus,
are most admirably adapted, as Sir Philip Egerton has well
pointed out, with the anchylosed condition of the atlas and axis,
to ensure the fixation of the head which is essential, in an active
predatory animal, to its swift and agile movements through the
water.

The costal processes or ribs commence in the Ichthyosaurus at
the axis or second cervical vertebra, and are continued through
the anterior two thirds of the caudal region of the spine. Those of
the cervical and anterior part of the thoracic regions are slightly
bifurcate at their proximal extremity, and are articulated partly
with a tubercle on the centrum, which represents the inferior
transverse process, and partly to the outside of the base of the
neurapophysis : as they become placed further back, the two
heads become gradually blended into a single expanded proxi-
mal extremity, which at length becomes a simple convex tu-
bercle in the ribs of the caudal region. The ribs quickly in-
crease in length, which is greatest at the middle of the thoracic
abdominal cavity : from this point they become gradually ab-
breviated to the sacral vertebrae, and then suddenly contract
into short and straight appendages, which progressively dimi-
nish until they finally disappear. Those ribs, which are bifur-
cate or bilobed at their upper extremity, are traversed by a longi-
tudinal impression extending from the -aw^q of bifurcation along

102 REPORT— 1839.

the whole of the anterior and posterior surfaces, giving to the
bone the appearance of its being composed of two ribs anchy-
losed by their sides. Mr. Clift has given a faithful view of this
structure in PL XIX. of the Philosophical Transactions for 1814.
It is gradually lost in the ribs at the posterior part of the tho-
racic-abdominal cavity, which from this part preserve the form
of simple osseous styles. The inferior or sternal extremities of
the opposite ribs are not immediately united together, but the
long hoop is completed by a sterno-costal arc composed of
transverse styles, which are more slender and fewer in number
than in the Plesiosaurus.

In comparing the vertebras in different parts of the spine of
the Ichthyosaurus, modifications of structure present themselves
which are somewhat analogous, though minor in degree, to those
already described in the Plesiosaurus. The principal difference
to be noticed is that the lower tubercle for the attachment of the
rib never wholly quits the centrum : any detached vertebral
centrum, therefore, that might be discovered, which had no
lateral tubercle or articular surface for a rib, might be safely
pronounced, whatever the form of its anterior and posterior ar-
ticular surfaces, not to have belonged to a true Ichthyosaurus,
provided it was not compressed laterally, as in the small termi-
nal ribless caudal vertebrae which supported the caudal fin in
the Ichthyosaurus.

In the anterior sixteen vertebrae of the Ichthyosaurus commu-
nis, or for a third part of the spine extending between the cranium
and pelvis, the lower costal tubercle only is developed upon the
body, the upper tubercle or articular surface resting on the neur-
apopliysis, or not being distinct from the neurapophysial ar-
ticular surface. In the twenty succeeding vertebrae, both the
costal tubercles are developed on the side of the centrum below
the neurapophysial depression. The upper of these tubercles is
at first placed close to the neurapophysial pit, and thence takes
gradually a lower position on the side, so as to approach more
nearly to the inferior tubercle ; at length near the 40th vertebra,
at a short distance beyond the iliac bones, the two tubercles
blend together and form a single ridge. This ridge as the
caudal vertebrae recede from the trunk gradually changes its
obliquely elongated direction for a transverse one, or becomes a
rounded tubercle ; and at length disappears about the 80th
vertebra. It is at this part of the spine in the Ichthyosauri
communis and intennedius that the abrupt bend or dislocation
of the tail usually takes place ; and here three or four of the
vertebral centres are more compressed than those which im-
mediately precede or follow them, and their margins are raised,
as if by forcible compression. The caudal vertebrae are more

BRITISH FOSSIL REPTILES. 103

especially characterized by a small triangular tubercle developed
at each of the four angles of the quadrilateral space which
forms the inferior surface, the tubercles being largest at the
anterior angles : this tubercle, with the corresponding one on
the adjoining vertebra, forms the surface of articulation for the
caudal haemapophyses, which are short and slightly curved
simple bones, not joined together at their distal extremities so
as to constitute a bone of the chevron shape, as in the existing
Saurians : these haemapophyses disappear in the last 20 vertebrae.

Besides their double-cupped articular surfaces and the pre-
sence of the costal tubercle, the vertebral centres of the Ichthyo-
sauri generally differ from those of the Plesiosauri in having a
more angular contour, which sometimes forms nearly a true
hexahedron.

Each sterno-costal arc consists, as Mr. Hawkins correctly
states*, of five bones. These are slender transversely elongated
ossicles, which overlap each other in the way which has been
described in the Plesiosaitrus. The median piece is generally
symmetrical in shape, and sends off from its middle part a short
thick process both forwards and backwards, or in tiie longitu-
dinal axis of the body. In the symmetrical median pieces, the
elongated lateral processes are continued from the middle of
the short longitudinal one ; in the unsymmetrical median pieces
one lateral process comes off from the anterior and the other
from the posterior portion of the longitudinal process. The
lateral processes bend slightly backwards, and diminish to a
point. A slender cylindrical styliform process pointed at both
extremities is spliced as it were to the anterior part of each
lateral., process of the median piece, which it equals in length ;
it extends however a short distance beyond its lateral extremity.
A second styliform ossicle is similarly adapted to the anterior
part of the lateral or outer extremity of the preceding piece,
but the lateral extremity of the third process is not pointed
but is slightly expanded and abruptly truncated in order to join
the lower extremity of the true ribf. In the singleness of the
median piece and the development from its middle part of a
short longitudinal process may be discerned an affinity to cer-
tain Lacertian Sauria, as the Polychrus marmoratus, Cuv.,
while in the double overlapping lateral pieces we perceive a re-
semblance to the condition of the abdominal ribs in the Croco-
dile. If the median piece in the Ichthyosaurus were removed,

* Memoirs on Ichthyosauri, p. 21.

t In a rare and beautiful specimen of this sterno-costal apparatus of a spe-
cies of Ichthyosaurus from the lias of Lyme Regis, kindly transmitted to nie
for examination by Mr. Conybearc. there are 19 slender arcs^ each composed
of the five pieces above described.

104 REPORT — 1839.

the sterno-costal arc would be reduced to the same number of
elements as in the Crocodile : if the lateral styles were taken
away, it would i-esemble the simple sterno-costal arc of the
Polychriis.

The Pectoral Extremity. — We have already remarked that
the extremities of the JEnaliosawi offer the nearest resemblance
in their bony structure to the paddles of the Cetacea. But this
resemblance is limited to the radiated system of bones, i. e. to
the hrachium, antibrachium and mcmus. The mode in which
the locomotive member is connected with the trunk is entirely
different in the two aquatic tribes. In the Cetacea the pectoral
fin is attached to a simple scapula with a rudimental acromial
and coracoid process, and is merely suspended in the flesh. In
the Ichthyosaurus y as in the Plesiosaurus, the pectoral fin is
connected with, and must have acted upon a powerful and re-
sisting osseous arch, having the sternum for its keystone. The
sternum in fact here exists solely for the function of the anterior
members, and does not enter at all into the formation of the
costal arches or the respiratory cavity. In the Cetacea on the
contrary the sternum is limited to its connection with the ribs,
and to the completion of the thoracic receptacle of the large
and highly developed lungs.

In the Ichthyosaurus the representative of the sternum is
analogous to the episternal element as it exists in the Orni-
thorhynchus and Lacertian /S'«?«n«, and, as in many of the latter
tribe, it presents a triradiate form. One branch occupies the
median line of the pectoral arch, is broad and flat, and rounded
posteriorly; the other two rays branch off from each of the
anterior angles of the median piece, and, diverging laterally, fol-
low the curvature of the superimposed clavicles, to the posterior
and middle part of which they are closely atached : as they pro-
ceed outwards, these lateral rays of the episternal bone gradually
diminish to a point.

The scapula is a short but stout and broad bone presenting
the simple parallelogramical form which characterizes it in the
Oviparous Vertehrata. The anterior margin is fixed to the
clavicle and to the extremity of the lateral process of the epister-
num : the inferior extremity presents two facets, one of which is
attached to the coracoid bone, the other forms part of the arti-
cular surface for the humerus.

The coracoid bones, which constitute at their contracted and
thickened outer extremities the remainder of the glenoid ca-
vity, become suddenly and remarkably thinner and expanded
as they pass inwards to articulate with the episternal bone.
They are also complicated each in the young Ichthyosauri with
an epiphysial piece wedged into the angle between their ante-

BRITISH FOSSIL REPTILES. 105

rior margins and the episternum, which pieces correspond with
the epicoracoids of the Lacertian Sauria and Ornithorhynchus.
The existence of these bones I have determined in some of the
beautifully worked out skeletons in the collection of Mr.
Hawkins.

The clavicles are strong, elongated, slightly curved bones,
thicker in the middle than at their extremities, articulated by
an oblique suture to the transverse processes of the episternum
with their median extremities in contact, but not anchylosed
together as in the furculum of the Bird : in this respect, as in
their connection with the episternal bone, they correspond with
the clavicles of the Ornithorhynchus. In the entire mechanism
of the complex pectoral arch, indeed, the resemblance between
these very different animals is remarkably close, as Mr. Clift
first pointed out, while the difference which both these air-
breathing aquatic animals present in this part of their osseous
structure from the Cetacea is very striking. In the Cetacea,
for example, there is not any osseous bar interposed between
the two shoulder-joints, or the centres on which the fore paddle
worked, while similar movements of the fore paddles of the
Ichthyosaurus had, and in the Ornithorhynchus have their
momentum transferred to, and resisted by, not less than three
transverse bones, viz. 1st by the clavicles, 2nd by the epi-
sternal forks and the scapulae, and 3rdly by the coracoids and
scapulae. To what difference in the habits of these species had
these differences of structure reference ? Most assuredly it could
not relate exclusively to the necessity of rising to the surface to
respire air, as conjectured by Sir Everard Home* ; for this
necessity existed in all the three types of aquatic animals, and
much more imperatively in the Cetacea than in the Enalio-
sauria. In the Ornithorhynchus the anterior extremities are
directed outwards, as in the marine Cetacea and Knaliosauria ;
but they are destined in that quadruped to be applied not only to
displace water, but to be occasionally pushed against a more re-
sisting surface, as the dry land : in order therefore to enable the
fore limbs to react with due force upon the body, a strong appa-
ratus of bone is introduced between the two shoulder-joints,
whereby these parts are prevented from yielding inwards and com-
pressing the soft muscular masses. But in the Cetacea, which
were never intended to quit the deep, such an appai'atus of bone,
as it would have added unnecessarily to their weight, has been
excluded from the mechanism of their anterior extremities : and
hence it is that, when they have the misfortune to be stranded,
they are unable to regain their native element. The instrument

* Phi!. Trans., 1818.

106 REPORT— 1889.

for bringing the head to the surface of the water for the purpose
of breathing is the same in both the Monotreme and the Ceta-
cean, viz. a strong, muscular, horizontally flattened tail. In
the Ichthyosaunis a pair of hinder paddles (which in the large-
headed species, as the Ich. platyodoji, are equal in size with
the fore paddles,) must have fully compensated for that dif-
ferent construction of the tail, which, while it rendered it less
efficient as a means of raising the head to the surface, made it a
more perfect instrument in ordinary natation ; and the suf-
ficiency of this compensation will be better appreciated when it
is remembered that the Reptilian structure of the lungs and
heart of the Ichthyosaurus would allow it to dispense with so
perfect a machinery for rising to the surface as was essential to
the warm-blooded aquatic species above cited.

For what purpose then were sterno-clavicular and coracoid
arches assigned to the Ichthyosaurus ? Doubtless that the ante-
rior paddles might be subservient to locomotion not only in the
water but on land ; and that, when applied to the resisting soil,
they might react with due force upon the trunk. It is very con-
ceivable that the Ichthyosaurus like the Crocodile mayhave come
ashore to sleep : it is most probable that they resorted to the
shore to deposit their eggs, supposing them to have been ovi-
parous, as the sum of the analogies deducible from their osseous
texture would indicate. The hind paddles would also be ser-
viceable in terrestrial progression as in the Ornithorhynchus^
while ill the strictly marine Cetacea they could readily be dis-
pensed with.

The radiated bones of the anterior extremities consist of a
distinct humerus, radius and ulna, carpal, metacarpal, and pha-
langial bones.

Both the brachial and antibrachial bones of the Ichthyosaurus
are much shorter and broader in proportion to their length than
are the corresponding bones of the Plesiosaurus. This is more
particularly the case with the radius and ulna, which are usually
broader than they are long, and closely resemble the carpal
bones which succeed them. The limits of the carpus can be by
no means so easily defined as those of the antibrachium. The
first row of bones which succeeds to the radius and ulna includes
three polygonal or rounded flat bones, generally broader than
they are long ; the next row includes three or four similar bones ;
and then instead of being succeeded by elongated metacarpals
and phalanges, as in the Plesiosauri, the fin is supported by
numerous rows of smaller but similarly-shaped flattened ossicles,
increasing in number as they diminish in size, to near the extre-
mity of the paddle. These small flattened ossicles are arranged
in from three to six digital series, and are generally dovetailed

BRITISH FOSSIL REPTILES. 10/

into each other at the sides, so as to prevent any independent
movement, but to constitute one uniformly resisting framework
of a povrerful fin. The integument extended beyond the bones
further than might have been anticipated, and its posterior
margin appears to have been supported by a series of slender
bifurcate cartilaginous rays. A disparity in the size of the
anterior and posterior extremities has usually been assigned as
a generic structure or character of the Ichthyosaurus ; but in
the species in which the head is unusually large, as the Ich. pla^
ti/odon, the pelvic extremities are as large as the pectoral ones.
In most of the known species, however, the hinder paddles are
much smaller than the fore ones. In all they present a structure
which is closely analogous to that above described.

The Pelvic Extremity . — The pelvic arch consists, as in the
Plesiosaurus, of an ilium, ischium and pubis on each side. The
ilium is a short, simple, strong, compressed bone, slightly ex-
panding as it descends to combine with the ischium and pubis
in forming the acetabulum. Its upper and proximal extremity is
not connected by synchondrosis to the extremities of the sacral
ribs, but lies simply upon them, just as the scapula rests upon the
ribs at the anterior part of the thorax. This is a condition of
the ilium which is of great interest, and is peculiarly character-
istic of the JEnaliosauria among Reptiles*. It renders their
pelvic extremities remarkably analogous to the ventral fins of
fishes, which are in like manner simply suspended in the mus-
cular mass and not fixed to a sacrum. The ischia and pubes
are both relatively much smaller than in the Plesiosauriis ; the
pubis is slightly expanded at its mesial or lower end, but the
ischium is a simple, elongated, slightly compressed bone.

The femur is usually longer in proportion to its breadth than
the humerus, and its posterior margin is more concave. It is
succeeded by two bones, which represent the tibia and fibula,
and resemble in their forms and proportion the radius and ulna
of the fore fin. Three irregular polygonal flattened bones suc-
ceed the tibia and fibula ; and then three or four longitudinal
series of similar bones follow, which gradually diminish in size
as they approach the extremity.

Such appears to be the structure of the skeleton which is
common to all the species of Ichthyosauri, so far as I have been
able to study their fossil remains, and which may, therefore, be
considered to characterize them generically.

The modifications of this structure which distinguish the
particular species next claim attention.

* Tho rudimental pelvic exU'emities of Serpents are simply suspended in the
muscles external to the adjoining ribs, as were those of the IdUhyosuunis.

108 REPORT— 1839.

Ichthyosaurus communis, Conybeare.

This species is characterized by its relatively large teeth, with
expanded or ventricose bases, and round, conical, slightly adun-
cate crowns, which taper more quickly and less regularly to the
apex than in the other species ; the apex is not very acute, and
the whole tooth is longitudinally furrowed, the base being sculp-
tured by coarse and deep grooves, with intervening convex
ridges. The upper jaw contains on each side from 40 to 50
teeth, of which 18 are implanted in the superior maxillary bone.
In the lower jaw there are on each side between 25 and 30 teeth.
The basal ridges in the large teeth are sometimes transversely
scored, and bifurcate as they approach the base, towards which
the bifurcations gradually diminish in size ; when the whole
may not unaptly be compared to the contracted head of a small
Pentacrinite. The anterior paddles are three times larger than
the posterior ones, and, as compared with the other known
species of Ichythyosauri, are relatively broader, and contain a
greater number of digital ossicles*.

With respect to the size of this species, it appears to be se-
cond only to the Ich. jilatyodon.

In the museum of Viscount Cole there is a head of the Ich-
thyosaurus communis which measures in length two feet nine
inches, indicating an animal of 20 feet in total length. The series
of teeth in the dentary bone of the lower jaw is one foot ten
inches and a half in extent.

The head of this species is expanded posteriorly, but quickly
contracts to the base of the jaws, which are prolonged and
somewhat compressed ; towards their apices the profile ab-
ruptly converges to the tangential point. The basi-occipital
bone in this species differs from that of the Ich. platyodon in
having a shallower depression on the under part anterior to the
condyle, and its length is greater in proportion to its breadth.

In the composition of the cranium may be noticed the very
small size of the median frontals, and the great share which
they have in the formation of the parietal foramen, of which
only the posterior angle lies in the interparietal suture. The an-
terior and posterior frontals form exclusively the upper bomid-
ary of the orbit. There are seventeen sclerotic plates in each
eye, the length of each plate being equal to half the diameter
of the central circular space. The orbit and eye are relatively
smaller than in the Ich. tenuirostris or platyodon. The nostril

* Mr. Hawkins first appreciated this character of the present species ; he
states that " the metacarpus has eight bones ; the nine fingers contain no less
than two hundred and twelve." — Memoirs, &c., p. 28. He changed the name
assigned to the species by Mr. Conybeare, in order to express this pecu-
liarity.

BRITISH FOSSIL REPTILES. 109

appears to be bounded by a straight line above and a curved one
below. The upper maxillary bone receives the anterior part of
the malar bone in a notch ; and the slender, elongated malar
forms the whole inferior boundary of the orbit.

The parietal transverse processes are excavated posteriorly
for muscular insertions.

The extent of the symphysis of the lower jaw is nine inches,
where the whole length of the jaw is two feet nine inches.

The surangular bone is perforated by a small foramen.

At the posterior part of the jaws the teeth diminish in size as
they are situated further back. In the large head in Lord Cole's
museum the longest tooth presents an exserted crown of two
inches in length, and seven lines diameter at the base.

The surface of the cranial bones presents a silky appearance,
owing to the fine striae with which it is impressed.

The vertebra are in slight degree more compressed in the an-
tero -posterior direction than in the Ich. intermedins. I count
forty vertebrae between the occiput and that which from its re-
lative position to the iliac bones might be regarded as the sacral
vertebra; from this to the extremity of the tail I have found
100 vertebrae ; in all 140 vertebrae.

The humerus is shorter and stouter in proportion to its length
than in any other species of the genus. The fore paddle is re-
latively broader than in the Ich. intermedins, and appears to have
an additional series of digital bones. The component phalanges
are transversely oblong ; the larger ones are hexagonal or penta-
gonal, with the angles more or less rounded off; they become
more rounded as they diminish in size towards the extremity of
the digital series. I cannot perceive that distinction in the form
of the phalanges of the Ich. communis as compared with those
of the Ich. intermedins which led Mr. Hawkins to designate the
latter cheiro-paramekostinus or oblong-boned. Neither does the
pointed form of the paddles peculiarly characterize the Ich.
communis.

After a careful comparison of the most perfect specimens of
the anterior paddles of the two species, Ich. communis and in-
termedins, I am disposed to consider that the Ich. communis
has an additional digital series, and about fifty additional pha-
langial ossicles, increasing upon the whole the breadth and
power of the anterior fins. This increase in the strength of the
powerful locomotive members accords with the more robust
character of the head and teeth.

I am unable to fix upon any one useful distinguishing cha-
racter in the hind paddle, between the Ich. communis and in-
termedins.

They resemble each other more closely in the structure of

110 REPORT 1839.

their locomotive extremities than any other species of the genus.
They are most easily and certainly distinguished from each other
by the form and relative size of the head and teeth.

Localities. — The Ich. communis is the most common species
in the lias at Lyme and Charmouth. It also occurs in the lias
limestone at Street^ but is much rarer there than the Ich. inter-
medius. Remains of the Ich, communis liave been met with in
the lias at Keynsham, and near Nembroth, Bristol. A beautiful
head and other parts less complete of the Ich. comtmmis, from
Barrow-on-Soar, are preserved in the museum of the Philoso-
phical Institution of Birmingham. This species is associated in
the lias at Barrow with the Ich. tenuirostris and interme-
dins.

Prof. Sedgwick has parts of a specimen of this species from
the lias of Stratford-on-Avon. Two skeletons of young Ich.
communis in the Professor's collection both present the usual
abrupt bend in the tail.

The Ich. communis is undoubtedly present in the lias at Boll
in Wirtemberg, where it is associated principally with the Ich.
tenuirostris.

Ichthyosaurus intermedins.

Mr. Conybeare thus characterizes this species : ^^ The upper
part of the teeth is much more acutely conical than in the Ich.
communis, and the striae less prominent, yet they are less slen-
der than in /. tenuirostris','' and whereas in /. com?nunis ?ind I.
Platyodon the coronoid (surangular) disappears on the out-
side, (being overlaid and concealed by the overhanging flap of
the dental,) before the similar concealment of the angular bone,
in Ichthyosaurus intermedius the angular draws itself up be-
neath the coronoid before the coronoid is thus covered up itself*.

The lower surface of the basi-occipital bone is but slightly
excavated anterior to the condyle. The maxillary portion of
the skull is relatively shorter, and converges more regularly to
the snout, than in the Ich. cotmnunis; and the teeth are longer,
more slender, and more numerous.

In a skeleton in Mr. Johnson's museum at Bristol I counted
:H: teeth.

The vertebrae present simple concavities at their anterior and
posterior extremities ; they increase in general size, and their
spines grow wider in the antero-posterior diameter from the
cervical to the pelvic region, and thence gradually diminish.

* Mr. Conybeare refers to the figure of a beautiful specimen (PL XVII.
p. 112. vol. i., 2nd Series, Geol. Trans.) as displaying the latter structure. It
is nevertheless obvious in that figure that the so called coronoid x x disappears
beneath the dental a before the angular piece v similarly disappears.

BRITISH FOSSIL RKPTILES, 111

The iliac bones are situated opposite the 44th and 45th verte-
brae, both which have the two costal tubercles distinct. These
become blended into a single oblong oblique surface at the 48th
vertebra : this surface is situated as usual near the anterior and
lower margin of the centrum. A space equal to one diameter
and a half of the costal pit intervenes between them and the
neurapophysial surfaces.

In a skeleton in Mr. Hawkins's collection there are 126 verte-
brae. The two costal pits become blended at the 48th vertebra ;
the single tubercle disappears at the 76th vertebra, where the
bend of the tail commences. Here three or four of the ver-
tebrae are more compressed in the antero-posterior direction
than those that immediately precede and follow them. The ribs
are slender, and become flattened and longitudinally grooved at
their distal extremities. They become straight, short, and like
transverse processes after the 42nd pair.

There are 103 vertebrae in Mr. Johnson's fine skeleton of this
species from Charmouth, but the series is not complete. In a
beautiful skeleton of the Icfi. intermedius from the lias of Lyme
Regis, in the collection of Miss Conybeare, the tail exhibits
the usual fracture or bend, which takes place at the 78th ver-
tebra.

In the lower jaw the surangular is continued further forwards
than the angular, before it is overlapped by the dentary ; but
this is not continued so far forwards as in the Ich. communis.

The surangular bone presents a longitudinal notch on its out-
side, which begins a little anterior to the articular cavity, and
becomes gradually shallower as it advances forwards. The
length of the lower jaw is to that of the vertebral column as
3 to 11.

In a small specimen of Ich. intermedhis in Lord Cole's col-
lection in which the upper maxillary bone measured 2 inches 8
lines, the diameter of the eye-plates was 2 inches, and that of
the pupillary space 1 inch. I count 17 sclerotic plates.

The transverse portion of the episternum is rather longer and
thicker than the median longitudinal piece.

The clavicles are very long and strong, especially at the
middle ; they are concave at their inner surface.

In the coracoid bone the humero-scapular articulation is of
less extent than usual; the upper notch is as long and not
deeper than the lower one ; so that the neck of the scapulo-
humeral articulation is longer than in the Ich. platyodon or
tenuirostris.

The radial margin of the scapula is straight; the outer sur-
face at the expanded humeral end is slightly excavated.

112 REPORT— 1839.

The fore-paddles have the same disproportionate size when
compared with the hinder ones as in the Idt. commwiis ; but
they are not quite so broad in proportion to their length.

I have found seven series of digital bones in the more perfect
specimens of the fore paddle. The first or radial digit divides
after the fifth phalanx, and a supernumerary row of small bones
is situated at the ulnar edge of cue paddle. The distal ossicles
present a similar transversely oblong hexagonal or pentagonal
or rounded form as in the Icli. communis. 1 have seen in young
specimens of both species a small perforation or pit in the
centre of the phalangeal bones ; this marks the situation of the
entry of the blood-vessels. It is not, as Mr. Hawkins seems to
suppose, a specific peculiarity of the intermedius.

This species appears to be the most common, if not the most
generally distributed of the Ichthyosauri.

It is smaller than the Ich. communis. I have not seen any
specimen exceeding seven feet in length.

Localities. — The remains of the Ichthyosaurus intermedius
are common in the lias of Street ; they have been found at
Lyme Regis and Charmouth ; in the lias near Weston, Bath, and
Bristol ; at Keynsham ; in the lias at Charlton, about two miles
from Cheltenham ; and at Bedminster ; in the limestone lias at
Stratford, Warwickshire; likewise at Barrow- on-Soar, Leices-
tershire, but here less common than the Ich. communis. The
Ich. intertnedius also occurs in the lias near Whitby and Scar-
borough ; in the lias of different parts of Yorkshire ; at Bolsover
in Nottinghamshire ; at Whitton in Lincolnshire ; at Walgrave
in Northamptonshire. In almost every museum, indeed, I have
found remains more or less perfect of this species.

The head of the Ichthyosaurus from the lias-field of Boll,
figured by Prof. Jager, does not belong, as he conjectures, to the
Ich. intermedius, but to the species I shall presently have to
describe under the name of Ich. acutirostris, and which is more
nearly allied to Ich. tenuirostris* .

Ichthyosaurus platyodon, Conybeare.

giganteus, Leach.

Cheiroligostinus, Hawkins.

The species which I am now about to describe is that which
Mr. Hawkins has figured in his memoirs on Ichthyosauri
(PI. Til.) under the name of Cheiroligostinus, and of which
Dr. Leach had previously figured portions of the jaws and teeth
under the name of Ich. giganteus. The skull and scapula

* The small specimen of Ichthyosaurus figured by Sir Everard Home under
the name of ' Proteosaurus' belongs to the pi-esent species and not to Ich. te-
nuirostris as Ciivier supposed.

BRITISH FOSSIL REPTILKS. 113

figured in the Philosophical Transactions for 18] 4, Plates XVII.
— XX. , belong to the present species.

The name jjlatyodon, proposed by Mr. Conybeare for the
present species, is expressive of the form of the crown of the
tooth, which is conical, subcompressed, the convex surfaces
meeting on each side at a sharp edge : it further differs from the
tooth of the Ich. communis in not having the basal grooves con-
tinued so deeply upon the crown, which, on the contrary, often
present a smooth and polished surface*. The most prominent
and distinctive character of this species is the equality of the fore
and hind paddles as to size, and the comparative simplicity of
their structure as to the number of digital phalanges and ossi-
cles composing them. The discovery of this structure is due to
Mr. Hawkins.

The head is relatively longer in proportion to the trunk than
in the Ichthyosaurus communis or Ich. intermedins. The length
of the trunk, e. g., includes only one length and a half of the
head, while in the Ich. commy^iis it includes rather less than two
lengths of the head, and in the Ich. intermedins rather more.

The head of the Ich. platyodon is also longer in proportion
to its breadth than in the Ich. intermedins, but the jaws are
relatively stronger on account of their greater relative breadth,
and their less gradual attenuation to the rostral extremity.
The lower jaw is remarkably massive and powerful, and pro-
jects further backwards beyond the joint than in the preceding
species.

The orbit is relatively longer than in the preceding species :
the upper maxillary boue is excluded from the formation of any
part of its circumference by the union of the malar with the
lachrymal bone. In a magnificent fragment of the cranium of
this species in the collection of Mr. Johnson of Bristol the orbit
measures one foot in diameter.

The nostril has a more elongated elliptical form than in the
Ichthyosaurus intermedins or Ich. communis.

In the composition of the lower jaw I find that the angular
bone is continued further forwards before it is covered by the
overlapping dental piece than in the Ich. iyitermedius or Ich.
communis, a structure which contributes to the strength of the
lower jaw in this gigantic species.

The teeth I have not found to exceed 45-45 in the upper and
40-40 in the lower jaw. Their crowns are more frequently
found to be snapped off than in the smaller species, a circum-
stance which is indicative of the greater violence with which
they had been used.

* In the collection of Mr. Johnson of Bristol there is a tooth oH\\q Ich.j)laty~
odon which measures two inches and a half in length : its crown, which, as usual,
is pretty smooth and compressed, measures one inch.
1 8.39. I

114 REPORT— 1839.

The vertebrae have their bodies more compressed in the an-
tero-posterior direction than in most other Ichthyosauri. From
the occiput to the iliac bones I count 45 vertebrae, and thence to
the end of the tail 75 vertebrae, making in all 120. From the
dentata to the 25th vertebra inclusive, the centrum is charac-
terized by two well-marked tubercles on each side for the arti-
culation of the ribs. It is one of these vertebrae which is figured
(in the inverted position with the spinal canal downwards) in
PI. XIV. of the Philosophical Transactions (1816), illustrative
of Sir E. Home's second memoir on the Ichthyosaurus. The
remaining vertebral centres present only a single surface for the
articulation of the rib : the spinous processes are thicker, shorter,
and more rounded superiorly, than in the Ich. intermedins or Ich.
communis : their articular processes for mutual interlocking are
well developed, especially at the anterior part of the spine.

The ribs commence, as usual, at the second cervical vertebra ;
they increase in length to the twenty-fifth, and thence diminish,
at first gradually, but after the fortieth more suddenly. The
forty-fourth pair is straight, and they are continued, gradually
diminishing in length, attached by a simple head to the rudi-
mental transverse process on each side of the body of the verte-
bra, as far as the 100th vertebra, counting from the atlas.

Pectoral Extremity, — The scapula* is a strong bone, with the
upper or dorsal extremity truncated and slightly expanded, the
anterior margin nearly straight, but slightly produced at its
distal end ; the posterior margin is slightly convex in the middle,
moderately concave above, and very concave below ; the inferior
extremity is expanded to receive the articular ends of the cora-
coid bone and humerus; the posterior part of this articular
extremity is the thickest part of the bone.

The coracoid has a more extended scapulo-humeral surface, —
the scapular portion being the shortest, and has a narrower and
deeper upper notch, than in the other species of Ichthyosauri.
The internal surface of this bone is flat, but slightly concave
below ; the ento-sternal margin is thickened, the external sur-
face is slightly convex. In Lord Cole's collection there is the
coracoid of an Ichthyosaurus platyodon from Lyme, of which

* The following are the words in which two great comparative anatomists
have recorded their opinions respecting the present bone when first presented
to their consideration in a detached siate. Sir E. Home, by whom it was first
figured, says, {Phil. Trans., 1818,) " It bears a greater resemblance to the first
bone of the paddle than to any other ; so that if the animal [meaning the Ich-
thyosaurus] has a posterior paddle this must belong to it." But the posterior
paddle of the Ichthyosaurus being subsequently discovered, by which the as-
sertion just quoted was disproved, Cuvier ventured an equally confident opinion
respecting it, and says, " C'est un humerus de plesiosaurus^ mais il ne resemble
pas entierement a ceux du squelette de Lyme." A lesson of caution in pro-
nouncing an opinion on a detached fossil bone is strongly inculcated by the ill
success which sometimes attends the guesses of even the best authorities.

BRITISH FOSSIL REPTILES. 115

the long diameter is 8 inches 4 lines, the short or transverse
diameter 6 inches.

In the British Museum the scapulae of an Ich. platyodon are
preserved, each measuring 1 foot 5 inches in length, and 9 inches
in breadth at the distal end.

The humerus is as short in proportion to its breadth as in the
preceding species, but is more concave anteriorly than in the
Ich. communis or inter medius\ Its proximal rounded extremity
is tuberculated at its circumference, and the shaft is grooved
superiorly.

This character of the concavity or emargination of the ante-
rior edge of the bone is present in a more marked degree in the
radius or the anterior of the two bones which succeeds the hu-
merus, and neatly distinguishes it from the corresponding bone
of the Ich. com7nunis or intermedins. There is no sufficient
distinguishing character in the ulna, which diflPers only in size
from that of the other Ichthyosauri,

The rest of the anterior paddle is composed of small trans-
versely oblong bones, which gradually diminish in size to the
extremities of the digits ; and the limits of carpus and meta-
carpus can only be arbitrarily defined as in the other Ichthyo-
sauri. The first or carpal row consists of three bones, as in the
Ich. intermedins, but the radial or anterior ossicle is distinguished
in the Ich. j)latyodon by an anterior emargination corresponding
with that of the radius above. The same character is presented
by the corresponding bone of the succeeding series, beyond
which it is lost.

The whole paddle is not less clearly characterized, than the
individual bones above mentioned, by the comparative paucity
of its digital subdivisions ; these do not exceed three in number,
with two or three small supplementary ossicles on the radial
margin of the paddle, which may be regarded as the rudiment
of a fourth digit. The component phalangial ossicles are more
rounded in their contour, and less transversely elongated, than
in the previously described species : their margin is slightly
raised on the outer surface. Beyond the antibrachium I count
fourteen ossicles in each of the marginal, and fifteen in the me-
dian row, which, with the three supplementary ossicles, make
forty-seven in the whole fore paddle or manus.

The pelvic bones are characterized by their relative superiority
of size, more especially the ilium.

The femur, together with the other bones of the posterior
member, is still longer in proportion than in the other species
of Ichthyosaurus. It is only a very little less than the humerus :
its proximal extremity presents a large depression, probably for
the attachment of a stout ligament.

The tibia presents the same anterior emargination as the cor-
I 2

IIG REPORT— 1839.

responding bone of the fore extremity, and the same character
occurs in the tM^o succeeding ossicles forming the anterior mar-
gin of the paddle.

The middle bone of the first or tarsal row is distinguished by
a wedge-like process at its upper margin, which fits into the
interspace of the tibia and fibula. There are three principal
digital series as in the fore paddle, but the supplementary row
contains a greater number of ossicles, and is situated on the
posterior instead of the anterior side of the paddle.

The anterior digital series includes, counting from the tibia,
nine ossicles, the median row eleven, and the posterior ten os-
sicles : there are eight small ossicles in the posterior rudimental
digit.

Besides the comparative fewness of the digital ossicles in the
paddle of the present gigantic species, they are characterized by
their being placed at greater distances from each other in the
terminal or lower half of the paddle, indicating that the liga-
mentous substance which connected them together entered more
abundantly into the formation of the fin.

The imperfect spinal column, including 110 vertebrae, of an
Ich. idatyodon from Lyme, now in the British Museum, mea-
sures eighteen feet in length : but portions of the skeleton of the
Ichthyosaurus 'platyodon^ as the magnificent fragment of the
cranium in possession of Mr. Johnson of Bristol for instance,
have been discovered, which indicate individuals exceeding thirty
feet in length.

Localities. — The lias of the valley of Lyme is the chief de-
pository of this gigantic species, but its remains are pretty widely
distributed : they have been found in the lias of Glastonbury,
of Bristol, of Scarborough and Whitby, and of Bitton in Glou-
cestershire.

Vertebrae of this species occur in the lias at Ohmden, but not,

apparently, at Boll, where the Ich. communis and temm^ostris

occur : at least, the specimens referred, doubtfully, by Prof. Jager

to the Ich. lilatyodon have the characters of the Ich. communis.

Ichthyosaurus lonchiodon, O.*

A magnificent specimen of this species, measuring upwards
of 15 feet, formed part of the second collection of Saurian re-
mains purchased by Parliament of Mr. Hawkins, and now de-
posited in the British Museum.

The head somewhat exceeds, in relative size, that of the Ich.
plati/odon, to which the present species is closely allied : the
jaws are deeper, and taper less gradually to their extremities.
The teeth are more slender in proportion to their length than in
the Ich. communis or platyodon, and are straighter than in the
tenuirostris or intermedius. Their base is cylindrical, and re-

* y^O'/x'^' ^ifsfc, olov;, dens.

BRITISH FOSSIL REPTILES. 117

gularly fluted ; a smooth boundary divides it from the crown,
which is trarersed by liner grooves converging to the apex ; the
transverse section of the crown is nearly circular, not com-
pressed as in Ich. j)latyodo)i ; it tapers gradually to the apex,
which is nearer the posterior line than the central axis of the
tooth.

The vertebrae are thicker in their antero-posterior diameter
than in the Icli. platyodon : I count 45 between the occiput
and pelvis, and 120 in the skeleton above-cited; but the tail is
slightly imperfect. The scapula of the Ich. lonchiodon is more
equably and deeply concave at the posterior margin, and its
humeral extremity is relatively broader than in the Ich. platyo-
don. The bones of the extremities are thicker but shorter : the
radius is emarginate anteriorly : there are three phalanges, of
which the ossicles resemble in form those of the Ich. platyodon :
but the whole paddle is relatively less. This difference is still
more marked in the hind-paddle, which in the Ich. platyodo?i
is, on the contrary, very nearly equal in size with the fore-paddle.
Locality. — The lias of Lyme Regis, where the skeleton above^
noticed was discovered by Miss Anning.

Ichthyosaurus tenuirostris*, Conybeare.

grandipes, Sharpe.

chirostrongulostinus, Hawkins.

The form of tooth figured by Mr. Conybeare as characteristic
of the Ich. tenuirostris is one which it is very difficult to di-
stinguish from that which is presented by the teeth of a species
next to be described, and which in the form of its head is in-
termediate to the species called Ich. intermedius and/cA. tenui~
rostris. This species may, however, be recognised by other
characters afforded by the humerus, the radius and tibia, and
by the size and form of the paddle-bones, which have suggested
the synonyms to their respective authors cited at the head of
the present chapter.

But the most striking peculiarity of the Ichthyosaurus tenui-
rostris is that which Mr. Conybeare has happily chosen for its
specific denomination, viz. the great length and slenderness of
the jaw-bones, which are analogous in this respect to those of
the Gharrial, and which, in combination with the large orbits
and flattened cranium, give to its entire skull a close resemblance
to that of a gigantic Scolopax, with a bill armed with teeth.
The length of the snout is chiefly due to the prolongation of

* The characters derived from the relative length of the head, trunk, and
tail, and of the fore and hind paddle, quoted from Cuvicr, and assigned to
the present species by H. V. Meyer, in his work entitled " Pal^o/offica,"
p. 214, are tiiose of the Ich. intermedius, to which species the small specimen
figured by Home, in the Philosophical Transactions for 1819, and now in the
Museum of the Royal College of Surgeons in London, belongs, and not, as
Cuvier supposed, to the Ich. tenuirostris.

118 REPORT— 1839.

the intermaxillaries, and their analogues the dentary pieces of
the lower jaw. These latter pieces have a longitudinal groove
on their external surface near the alveolar ridge. The suran-
gular disappears beneath the dentary about half an inch anterior
to the nostril ; the angular continues longer visible on the out-
side of the jaw.

The teeth are more slender in proportion to their length
than in any of the previously described species : I count from
65 to 70 on each side of the upper jaw ; of these the posterior
third, or about 25, are implanted in the slender maxillary bones.
In the lower jaw there are about 60 teeth on each side. They
are directed more obliquely backwards than in the species pre-
viously described.

The parietals are divided by a persistent sagittal suture, and
the foramen is principally situated in this suture, the anterior
part only encroaching between the frontals. Each of the post-
erior parietal bifurcations runs parallel with, and is applied to
the outside of the supraoccipital bone. The median frontals
are also separated by suture ; they are relatively larger than in
communis, but do not reach the margin of the orbit. The
anterior frontals lie on the outside of the median frontals ; the
posterior frontals on the outside of the parietals. Cuvier states
that the post-frontals form the whole of the posterior boundary
of the orbit. In the Ich. tenuirostris this boundary is slender,
and presents a fine and deep smooth groove next the orbit.

I have already alluded to the large size of the orbits : they
are not less characterized by the slenderness of their inferior and
posterior parietes ; the diameter of the orbit equals that of the
posterior or occipital region of the cranium.

The malar bone is singularly long and slender, and brings to
mind its characteristic condition in Birds : its posterior extremity
is joined with a slender curved descending process of the zygo-
matic bone. The rest of the zygomatic element is much more
robust, and passes obliquely backwards to join the articular ex-
tremity of the tj'^mpanic bone, and to circumscribe the temporal
fossa below. The temporal fossa is bounded by the posterior
frontals, the parietal fork, and by a bone which Cuvier regards
as peculiarly Ichthyosaurian, and which extends from the post-
frontals to the end of the parietal fork. The nasal bones have
the margin which forms the upper boundary of the nostrils,
slightly convex, encroaching upon the nostril. The nostrils are
narrow and elongated, but apparently larger in proportion than
in the other Ichthyosauri, measuring two inches and a half
long in a head two feet in length now in the British Museum,
and figured by Mr. Hawkins in his 13th Plate. The rami of
the lower jaw soon unite, and the symphysis extends through
more than the anterior two-thirds of the jaw.

BRITISH FOSSIL REPTILES. 119

The vertebral column corresponds in its general slenderness
with the characteristic form of the head. The number of con-
stituent vertebrae appears to be at least as great as in any pre-
viously described species of Ichthyosaurus : they are more
variable in the antero-posterior direction, and have a more
rounded and less angular contour than in ?i\\j other species :
their anterior and posterior articular surfaces are simply con-
cave. A greater proportion of the terminal caudal vertebrse
present the laterally compressed form than in other Ichthyo-
sauri, which would indicate 1-hat the tegumentary caudal fin was
of greater relative extent. The atlas or odontoid epiphysis of
the vertebra dentata separates more easily from the body of that
vertebra than is usual in other species of Ichthyosauri; and
there appear to be only two subvertebral bones, viz. that beneath
the occipital condyle, which represents the atrophied body of
the atlas ; and the second, developed in the angle between the
axis and odontoid epiphysis ; the third, which is usually situated
between the axis and third cervical vertebra, is wanting in the
present species. This simplification of the apparatus for fixing
the neck accords with the light and slender character of the
head. The vertebrae gradually increase in thickness, or antero-
posterior extent, as they approximate the caudal region, whence
they gradually diminish in all their dimensions. But at the
posterior part of the abdomen, and beginning of the tail, they
are relatively thicker in the direction of the axis of the body than
in the other species of Ichthyosaurus. I count fifty vertebrae
between the atlas and the first caudal vertebra.

The costal tubercle in the caudal vertebrae is situated near the
anterior part of the centrum. The ribs are long and slender,
and appear, in the present sp'ecies, gradually to increase in
length to near the posterior end of the vertebral column, and
then to shorten more abruptly than usual.

The extremities of the Ich. tenuirostris are characterized in
the first place by a disparity in the size of the fore and hind
pairs similar to that which obtains in the Ich. communis and
Ich. intermedins, and the fore paddles are more particularly
distinguished by their massive proportions, as compared with
the vertebrae.

The clavicles are slender, slightly expanded at the middle, and
contracted at the two extremities ; their anterior margin is in-
flected about 1| inch from their sternal extremity. The sca-
pulae are relatively larger than in the preceding species, bent
and expanded at their humeral extremity.

The coracoids have a broad neck, a slight inferior emargina-
tion, and a deep and narrow superior notch.

In a well-preserved specimen of Ich. tenuirostris in the Bir-
mingham museum,

120 REPORT— 1839.

In. LineJf.

The length of the coracoid was 4 5

The breadth 3

The length of the humerus of the same specimen 3 10

Its breadth at the distal end 3

The humerus is characterized by the superior length of its
shaft, and the sudden hammer-like expansion of its distal arti-
cular extremit}'^, which, however, presents the usual flattened
shape. The anterior or sternal surface of the humerus is pro-
duced into a strong angular process ; its dorsal surface is nearly
flat. The radial condyle is most produced, and the breadth of
the radius equals nearly the transverse diameter of two of the
bodies of the parallel vertebrae of the spinal column. The ulna,
and the rest of the bones of the extremity, bear the same large
proportional size. In the Ich. iilatyodon the breadth of the
radius hardly equals the transverse diameter of a single parallel
vertebra. In the Ich. communis and Ich. inter medius the
breadth of the radius is less by one third than the transverse
diameter of a vertebra from the corresponding part of the body.
There is a small notch between the radius and ulna, at their
proximal end, in the Ich. tenuirostris.

It is the large size of the two antibrachial bones, and especi-
ally the radius, that renders necessary the hammer-like exten-
sion of the anterior condyle of the humerus. In a specimen of
Ich. tenuirostris from the Grafton Quarry lias near Warwick,
at present in the museum of the Philosophical Institution of
Birmingham, the radius and ulna are anchylosed together, and
to the humerus. The specimen described by Prof. Jager seems
to present the same condition. The radius is distinguished, like
that of the Ich. platyodon, by an emargination at the middle of
its anterior edge.

The manus commences by three transversely oval carpal bones,
and includes only four digital series of ossicles, which present
a moi'e rounded figure than in the previously described species,
but resemble most in this respect the paddle-bones of the Ich.
platyodon. The radial bone of the first or carpal series is
notched anteriorly like the radius itself, but this character is
not marked in the next bone below, as in the Ich. platyodon :
the radial finger is not bifurcated.

In the hinder extremity of the Ich. tenuirostris the femur,
like the humerus, has a longer shaft than usual, and also a
greater transverse extension of its inferior condyles. The tibia,
like the radius, is notched at its anterior edge, but the emargina-
tion is relatively wider and shallower, and notched also in a
slight degree in the corresponding ossicle of the tarsal series.

The ossicle which is wedged into the interspace between the
tibia and fibula is relatively smaller than the corresponding bone
in the other Ichthyosauri ; it seems, therefore^ rather to form a

BRITISH FOSSIL REPTILKS. 121

part of the cnemial than of the tarsal series ; this latter row of
three bones bein^ completed by the intercalation, in its middle,
of an ossicle which forms part of the third or metatarsal row in
the intermedius and communis. The character above noticed
in the temiirostris may be observed, in a slighter degree, in the
Ich. platyodon.

Size. — In the museum of the Bristol Institution there is a
magnificent though not complete skeleton of the Ich. temii-
rostris, which measures thirteen feet in length. In Mr. John-
son's private collection, in the same city, there is a lower jaw
of the Ich. temiirostris from Lyme Regis, which measures two
feet six inches in length : the exserted crown of one of the
largest teeth in this specimen measures one inch and a half in
length, and four lines in diameter across the base.

Localities. — The skeleton in the Bristol Museum is from the
lias at Lyme Regis, where the species appears to be, however,
less common than the Ich. communis and jilatyodon. The in-
complete specimen from the lias of Stratford-on-Avon, in the
museum of the Geological Society of London, and described by
Mr. Sharpe under the name of Ichthyosciurus grandipes, belongs
to the present species. Lord Cole possesses some characteristic
fragments from the lias in the neighbourhood of Bristol.
Evidences of the Ich. tenuirostris have been procured at Street
and Walton, and at Barrow-on-Soar, in Leicestershire*.

This species undoubtedly exists in the lias formations of Boll
and Amburg, in Wirtembergf, and in the Jura limestone near
Solothurn.

Ichthyosaurus acutirostris.

Under this name is indicated a species of Ichthyosaurus,
which appears to be more common in the lias formations of the
neighbourhood of Whitby than in those of Dorsetshire, although
specimens also occur in the lias quarries of Street and Walton.

The teeth of the Ich. acutirostris, when they occur sepa-
rately and singly, are hardly distinguishable from those of the

* Professor Sedgwick has an incomplete skeleton of the Ich. tenuirostris from
this localit}', in which the tail presents the abrupt and characteristic bend so
common in the present genus ; three of the ribs also of this interesting specimen
have been fractured during the lifetime of the animal, and the fractured ends are
rounded and expanded,andit is evident, that afalsejoint has been formed; theun-
intcrmittingrespiratory movements havingprevented acomplete osseous reunion.

f The skeleton of the Ich. tenuirostris in the Gymnasium of VVirtemberg is
in some respects more complete than are any of those yet preserved in the
museums of this country, not excepting the beautiful specimen in the museum
of the Philosophical Institution of Birmingham. It is well described and
figured by Professor Jjiger, in his treatise " De Ichthyosaiu'i Fossilis Speci-
minibus," fol. 1824, and has enabled me to ascertain the number of ribs which
surround the thoracic-abdominal cavity, and at the same time test the con-
stancy of the character derived from the form of the humerus and the emargi-
nation of the anterior edge of the radius and tibia.

122 REPORT — 1839.

tenuirostris, although when a series of them are compared with
a corresponding series of the tenuirostris, they are seen to
be upon the whole a little wider at their base in proportion to
their length. The most marked difference between these species
is the length of the jaws ; the intermaxillaries aiid dentary
pieces being intermediate in this respect between the Ich. inter-
medins and Ich. tenuirostris.

The best example of the remains of the Ich. acutirostris which
I have yet seen, is in the museum of the Natural History So-
ciety of Lancaster. It gives a profile view of the entire head,
and of one anterior paddle.

The length of the head is eleven inches ten lines, and the
alveolar dental series extends six inches six lines along the
border of the jaws. The vertical diameter of the entire skull
anterior to the orbit is three inches, and from this point
both the upper and lower jaws regularly converge, in almost
every direction to the end of the snout, which is sharper and
more spear-shaped than in the other species.

The teeth vary in length from three to five lines, and about
twenty-four may be counted in the space of three inches ; they
present a more regular alternation in length than I have ob-
served in the other species of Ichthyosauri. There are about
fifty teeth on each side of the upper, and forty on each side of the
lower jaw, in all about 180 ; they are slightly bent backwards.

The orbit is relatively smaller than in the Ich. tenuirostris,
but wider than in the Ich. intermedius ; its inferior and posterior
boundaries are thicker than in the Ich. tenuirostris.

I have not been able to found any characters on the structure
of the vertebral column in the Ich. acutirostris. The humerus
is relatively as long as in the tenuirostris, but is less expanded
at the distal extremity. The radius presents the same anterior
emargination as in the tenuirostris and platyodon. The phalan-
gial ossicles are of an irregular rounded form, and are arranged
in four digital series, presenting an arrangement as well as a
relative size, which is intermediate between those which cha-
racterize respectively the Ich. tenuirostris and intermedius.

Mr. Hawkins has figured two snouts apparently belonging to
this species in PI. XIV. of his Memoirs, one of which, the
larger and more complete specimen, was from the lias-quarry at
Street, the other from that at Walton.

Besides the localities indicated in the preceding description,
remains of the Ichthyosaurus acutirostris occur in the lias for-
mation at Boll in Wirtemberg.

Ichthyosaurus latifrons, Koenig. (Icones Sectiles, pi. xix.)

This species is founded on a specimen in the British Museum,
including a portion of the cranium, of which the anatomy

BRITISH FOSSIL REPTILES. 123

is admirably worked out, and part of the vertebral column.
Besides the character expressed in the specific name proposed
by the accomplished Mineralogist and Paleeontologist, whose
name is associated with the genus, of which the present'species
forms so interesting an addition ; the foramen parietale appears
to be unusually large ; and the articular surfaces of the bodies
of the vertebrae present a flattened circumference.
Ichthyosaurus latimaniis, O.

This species resembles the Ichthyosaurus cnmmujiis in the
ventricose, subobtuse character of the teeth, of which I have
counted twenty-nine on one side of both jaws.

The articular surfaces of the vertebrae are only concave in the
middle third part of their transverse diameter ; the rest of the
surface to the circumference is flat. They are stouter in the
pelvic region than in the Ich. communis. The chief difference
between this species and the Ich. communis obtains in the re-
lative sizes of their anterior paddles. In an Ich. latimanus
of six feet ten inches in length, and an Ich. communis five
feet two inches in length, the following were the respective
dimensions of the bones of the anterior paddle :

Icli. latimanus. Ich. communis.
Inch. Lines. Inch. Lines.

Scapula, length of 3 4 3

, breadth of humeral end .18 13

Antibrachial bones, breadth of . 2 5 17

Length of entire paddle ... 7 6 50

Breadth of ditto 3 6 2 8

Coracoid, intero-posterior diameter 3 8 2 4

, transverse diameter ..32 20

The clavicle was also proportionally powerful in the Ich.
grandipes, and measured six inches eight lines in length.

The head is relatively shorter in the Ich. latimanus than in the
Ich. communis ; in the present specimen the lower jaw mea-
sures one foot four inches, while in the Ich. communis above
cited the lower jaw measured one foot five inches.

In the nearly complete but dislocated skeleton in the mu-
seum of the Philosophical Institution at Bristol, on which the
present species is founded, I counted 114 vertebrae; the ter-
minal vertebrae of the tail presenting the compressed character
indicative, as before noticed, of the former existence of a ver-
tical tegumentary fin. Parts of the carbonized integument are
preserved on the slab of lias on which this interesting fossil
reposes ; there is a broad patch about four inches beyond the
last caudal vertebrae, being the first evidence I have yet met
with of the actual presence of the caudal fin. The traces of
tegument in the abdominal region are smoother than those
figured in Dr. Buckland's Bridgewater Treatise.

124 REPORT — 1839.

If, as I have conceived, the pectoral fin and the massive
sterno-coracoid arch relate to occasional reptation on the sea-
shore, it may be inferred from the partial flattening of the
articular surfaces of the vertebrae, in a species characterized by
a greater size and strength of the fore paddles, that it was more
terrestrial or littoral in its habits than the ordinary Ichthyo-
sauri.

Ichthyosaurus thyreospondylus.

In the museum of the Bristol Institution there are five verte-
brae of an Ichthyosaurus, of a compressed subpentagonal form ;
one of these, which has a vertical diameter of two inches and
a half, and a transverse one of two inches and a quarter, is
only nine lines in antero- posterior extent. The articular sur-
faces for the ribs are developed into short transverse processes,
the upper one projecting immediately beneath the neurapophy-
sial pit, and the lower one an inch lower down, and near the
anterior margin ; the anterior and posterior articular surfaces
are concave, but have a convex rising, in the form of the heraldic
fess, the base being equal to the breadth of the surface support-
ing the medulla spinalis, and the apex reaching to the centre of
the articular surface. This character I have not observed in
the vertebrae of any other species of Ichthyosaurus.

Ichthyosaurus trigonus.

I have been favoured by Miss Benett, of Norton House,
Warminster, with some rare specimens from her valuable col-
lection of fossil remains, among which is the body of a vertebra
of an Ichthyosaurus remarkable for the straightness of the
sides below the transverse process, from which point they con-
verge at an angle of 70°; the upper part of the body of the
vertebra, which supports the spinal and neurapophysial sur-
faces, is the broadest, and is bounded by a horizontal straight
line, the whole presenting a triangular contour. The well-
marked distinctions which this vertebra presents as compared
with any that I have seen which belong to the preceding
species, embolden me to regard it as indicative of a distinct
species, for which a provisional name is proposed expressive of
the form of the vertebra.

The anterior and posterior articular surfaces present the
usual concavity : the non-articular surfaces at the sides of the
vertebra are smooth.

Inch. Lines.

The antero-posterior diameter of this vertebra is 1

The transverse diameter 2 6

The vertical diameter 2 10

Locality. — Westbrooke, in Bromham, Wilts ; Kimmeridge
Clay.

BRITISH FOSSIL REPTILKS. 125

In reviewing the principal facts which I have endeavoured
to state succinctly in the foregoing pages, the first circumstance
that may arrest the attention is the superior number of species
which belong to the genus Plesiosaurus, as compared with the
genus Ichthyosaurus ; and since the circumstances which have
led to the discovery and collection of the fossils of the two
genera cannot be supposed to have materially differed, it may
be concluded that the Plesiosaurs were rifer in the ancient
seas of the secondary epoch, and manifested their typical struc-
ture under a greater variety of modifications than their more
powerful and destructive congeners. To the four species of
Plesiosaurus recognizably defined and described under the
names of dolichodeirus, macrocephalus, recentior, and tria-
tarsostmiis, or Hawkinsii, I have been able to add descrip-
tions or indications of twelve additional species ; the number of
Plesiosauri, of which remains have been discovered in the
secondary strata of Great Britain, amounting now to sixteen.

To the species of Ichthyosauri, which Mr. Conybeare has
so well defined under the names communis, intermedins, pla-
tyodon, and tenuirostris, a very great proportion of the fossils
which I have examined are unquestionably referable, the small
remainder affording evidence of only the six species indicated
under the names of lonchiodon, acutirostris, latifrons, latima-
nus, thyreospondylus, and trigonus.

The deviations from the typical structure of the genus as
exhibited in the common species called Ich. intermedins, M'^hich
these additional evidences present, are of small amount, the
chief being a greater proportional developement of the pectoral
arch and its appended extremities, which characterizes the Ich.
latimanus. In the other and better known species the prin-
cipal modifications of the Ichthyosaurian type are manifested
in the magnitude of the entire animal, the proportional deve-
lopement of the head, the comparative length and slenderness
of the snout, the proportional sizes of the fore and hind pad-
dles, and the shape and number of the ossicles composing
them. In the forms of the vertebrte there are but slight dif-
ferences, and scarcely any in the proportions of the different
regions of the vertebral column.

The part of the skeleton of the genus Plesiosaurus, which
has been subject to the greatest extent of modification, is the
cervical region, which becomes shorter and stronger as the
head increases in size; but the general shape of the head
appears to have presented less variety in the Plesiosaurs than
in the Ichthyosaurs. The modifications of the vertebrae in the
Plesiosaurs are many, though none are of very great extent.
The differences of form which the bones of the pectoral and

126 REPORT— 1839.

pelvic arches present are greater than in the corresponding parts
of the skeleton of the Ichthyosaurs, but those of the paddles
themselves appear to be fewer ; the number of carpal and tar-
sal bones varies from six to eight, but that of the digital ossi-
cles is much more constant than in the Ichthyosaurs.

With respect to the geological relations of the Enaliosauria,
or the extent of strata through vrhich their relics have been
traced, my researches are merely confirmatory of the generali-
zations already enunciated by Messrs. Conybeare and Buck-
land. The British Enaliosaurs extend through the vi^hole of the
oolitic period, including the lias and oolite proper to the weal-
den and chalk formations, the most recent depositary being the
chalk marl, in which Ichthyosaurian remains have been dis-
covered by Dr. Mantell, at Dover ; Dr. Buckland has found
similar remains in the Gault, near Benson, Oxon ; and I have
seen the humerus of a Plesiosaurus from the Gault, near Maid-
stone.

The following are the names of the species of Enaliosauriaj
in the order in which they are described in the foregoing
Report : —

1. Plesiosaurus Hawkinsii, Owen.

2. — dolichodeirus, Conybeare.

3. macrocephalus, Con.

4. brachycephaluSf O.

5. niacronms, O.

6. pachyonius, O.

7. arcuatus, O.

8. subtrigonus, O.

9. trig-onus, Cuvier.

10. brachyspondylus, O.

11. costatus, O.

12. dcedicomuSf O.

13. rugosus, O.

14. grandis, O.

15. trochanterius, O.

16. " ajinis, O.

1. Ichthyosaurus communis. Con.

2. intermedius, Con.

3. platyodon, Con.

4. ■ lonchiodon, ().

5. tenuirostris, Con.

6. : — acutirostris, O.

7. latifrons, Kcenig.

8. latimanus, O.

9. thyreospondylus, O.

10. trigonus, O.

127

Report on the distribution of Pidmoniferous Mollnsca in the
British Isles. By Edward Forbes, M.W.S., For. Sec. B.S.

The object of this Report is to ascertain the geographical and
geological distribution of Pulmoniferoiis Mollusca in the British
Islands. I shall consider the subject under three heads :

1st. A view of the various influences which affect their distri-
bution.

2nd. A detailed view of the distribution of the indigenous
species in the various districts of these Isles.

8rd. The relations of this division of our native Fauna to the
Fauna of Europe, and the distribution generally of the more re-
markable species.

One hundred and one indigenous undoubted species of Pul-
moniferous Mollusca inhabit the British Islands. Of these two
belong to the genus Arion, five to Limax, one to Testacellus,
one to Vitrina, two to Succinea, thirty-seven to Helix, three to
Bulimus, two to Achatina, one to Azeca, five to Clausilia, one
to Balea, twelve to Pupa, eleven to Planorbis, two to Physa,
eight to Lymneus, two to Ancylus, one to Carychium, one to
Acme, and five to Auricula.

These one hundred and two species are not equally distri-
buted throughout the country, neither are they most numerous
in the south, and decreasing gradually towards the north, or
vice versa. Their numbers vary in various places, and on in-
quiry we shall find this variation to depend on certain influ-
encing causes, the two great primary influences being climate
and soil. The influence of climate in Britain is indicated by
the reduced number of species found in the more northern
and colder districts, as compared with the number inhabiting
the provinces of the south and centre. It is also indicated
by the disappearance of species which inhabit all soils indiffer-
ently as we advance northwards, and by the presence of spe-
cies in certain situations in southern and warm districts which
usually avoid, or are sparingly found in such localities elsewhere.
It is further shown by the tendency of individuals to multiply in
temperate situations, and by the superior beauty of colouring
displayed by species inhabiting warm districts.

Were climate the sole influence, the number of species would
diminish as we advance northwards ; but, though we find such
a diminution very evident on comparing the extremities, the

128 REPORT — 1839.

increase of numbers in the central districts, as compared with
some of the southern, indicates an influence in some cases
more powerful than climate. This influence we shall find to
be in its nature geological. It is the influence of the struc-
ture of a country on its existing Fauna.

The influence of the various kinds of rocks is very diflTerent
and very important. Certain species, and even certain genera,
appear to prefer certain rocks ; but of all rocks limestone
is the most favourable to the number and propagation of spe-
cies. All kinds of lime rocks are not equally indifferent. Cer-
tain mollusks appear to prefer chalk, others oolite, others moun-
tain limestone. Thus we find Helix carthusianella chiefly asso-
ciated with chalk. Helix pomatia and carthusiana with the older
tertiary, the cretaceous and oolitic formations, and Helix scar-
burgensis with the coal formation. Other species are distributed
over all varieties of limestone rocks, but are not found on other
kinds of soil, such as Helix glabella, Helix lapicida, and Pupa
secale. The influence of all other rocks appears to be rather
negative than positive ; for, though several species limited in
distribution seem confined to certain rocks in our country, we
find them in other countries, where their distribution is more
general, indifferent as to the soil in which they live. In ge-
neral it is the mineralogical character of the rock which in-
fluences rather than its age. Limestone and sand influence all
species as regards propagation, individuals multiplying to a
much greater extent on calcareous and sandy soils than on slates,
clay, or granite. Basalt has a similar influence, and primitive
rocks generally are unfavourable either to the development of
species or individuals. In certain cases the influence even
of limestone may be completely neutralized by climate, as we
find in Shetland, where the limestone tracts present no ex-
ceptions to the general paucity of species and individuals in
those islands. Climate may also be seen overpowering the
negative geological influence in Guernsey, where Helix varia-
bilis multiplies to a great extent along M^ith several other spe-
cies on the unfavourable surfaces of granite and quartz rock.
In some localities certain species are confined to certain rocks,
which are generally distributed over all soils in others.

The order of influence of rocks on species is as follows, com-
mencing with the most influential :

1. Cretaceous and oolitic.

2. Carboniferous rocks and trap.

3. Tertiary.

4. Saliferous.

5. Slates.

6. Granite and gneiss.

ON BRiTISH PULMONIFEROUS MOLLUSCA. 129

Though geographical and geological causes mainly regulate
the distribution of Pulmoniferous Mollusca, there are circum-
stances which modify their influence in certain situations. One
of the most important of these is elevation. In some countries,
as in Switzerland, the influence of elevation is positive ; that is
to say, certain species occur at certain heights which are not
found at a lower level. In Britain the influence of elevation is
merely negative, the ascent of our mountains being charac-
terized by the absence of species, the species becoming fewer
as we ascend : towards the summit we find only Helix al-
liaria. The neighbourhood of mountains also affects a fauna,
the upland species predominating around their bases even
when the hills rise directly from the region of the plains. A
wooded district is peculiarly favourable to the multiplication of
land shells, especially the smaller Helices, Pupae, and Clau-
siliae, many of which we need not look for except in forests.
The species of trees which grow in woods must also be re-
garded, pinewoods especially being much more unfavourable
to a fauna than woods of any other kind. The presence of
the aquatic Pulmonifera in a province must of course depend
on the presence of water in the various forms of lake, river,
ditch, and canal, each being characterized by its own peculiar
species. The introduction of canals into a district must mate-
rially change the character of its aquatic fauna ; and there are
shells in the British lists, such as the Dreissena jpolymorpha,
which owe their presence almost entirely to the construction
of canals in their several localities. The nature of the beds
of the lakes, streams and ditches in a district, affects the
number and variety of species therein found. We need not
look for many Limnei or Planorbes on gravelly bottoms, or
for Ancylus on mud. The presence of many aquatic mol-
lusca is determined by the plants growing in the localities they
frequent. The neighbourhood of the sea exercises a most im-
portant influence on our fauna, both as regards the species and
the multiplication of individuals. The marine influence would
appear to be especially favourable to the propagation of spe-
cies. The shells found on sea-banks are generally found in
great numbers, as we see in the case of Bulimus acutus. Helix
ericetorum, Helix virgata, Pupa marginata, and others. This
is especially seen in the case of species common inland as well
as near the sea, as Vitrina pellucida, and Bulimus lubricus.
The presence of sand aids this multiplication of individuals,
but is not indispensable. The marine influence appears to be
favourable to the development of size and colour in a species.
Helix ericetorum is generally found larger on the sea-side than

1839. K

130 REPORT— 1839.

inland. The number of varieties oi Helix nemoralis and hor-
tensis found on sea-banks is much greater than when those spe-
cies are gathered inland, and their colouring generally more
vivid. When Helix aspersa is found plentifully near the sea,
as in the Isle of Man, Ayrshire, and other places, the banding
is much more distinct, and the ground colour brighter. Most
species found near the sea vary very much, and many spurious
species have been made in consequence, as we see in the cases
of Helix striata, Helix variabilis, and Bulimus acutus. The
last would appear to be confined in Britain to sea-banks,
and to those of the western coast only. This does not apply
to Ireland, where it is found both on the eastern and western
coasts, and also inland. The difference between the faunas of
the eastern and western coasts of England is very remarkable.
Rivers influence the fauna of a district by the introduction of
species not indigenous. Many of our local lists are swelled by
the names of species collected from the rejectamenta of neigh-
bouring streams. A stream flowing from a mountain-range into
a plain will convey many species into the latter, which are pro-
perly inhabitants of the former. In Britain, where there is no
positive influence of elevation, this is of comparatively little con-
sequence ; but the case is different on the continent, where
large rivers, such as the Rhine and Danube, convey the in-
habitants of the Alps into the plains of Germany. Even
in our own country such rivers as the Thames and Severn
are likely to give rise to many fallacies as regards the local
distribution of a species. Man's agency may materially affect
a fauna, and has affected that of Britain. Bulimus decollatus,
Bulimus clavulus, Clausilia solida, and Testacella Maugei,
have been introduced into the British Hsts by such means. In
the cases of the above-mentioned species the carriage of plants
from other countries has been the medium. It has been as-
serted that Helix pomatia was first introduced into Britain for
purposes of food ; but there are good grounds for regarding it
as an aboriginal native. The thriving of such introduced
species must depend on the locahties to which they are trans-
ported ; and should a species, the distribution of which is
mainly influenced by geological causes, be introduced on a
soil similar to that of its native habitat, it is especially likely
to thrive and multiply. Species may be introduced into a local
fauna by means of ballast. On the banks of the Frith of
Forth we find numerous dead shells of Paludina vivipara and
impura, and Neritina fluviatilis, none of which inhabit the
district, but which have been conveyed thither in ballast,
thrown into the water, and again cast up on the shore. Land

ON BRITISH PULMOXI FERGUS MOLLUSC A. 131

and fresh-water shells from the south of England may thus be
found on the ballast-hills on the banks of the Tyne. Gene-
rally the shells are found dead ; but we find Helix carthusiana
living in Northumberland, having been introduced among bal-
last. Our marine fauna has been sadly vitiated by the same
cause. Fallacies in judging of the distribution of shells may arise
in consequence of the mixing-up of fossil with recent species.
Where the fossils belong to the older strata, or even to the
crag, such a mistake is not likely to occur ; but where they be-
long to the Pleistocene period it is extremely difficult to distin-
guish. This more especially applies to marine shells : indeed,
several undoubted Pleistocene fossils have found their way
into the catalogues of living British mollusca. But it may also
happen in the case of land and fresh-water species. In a
Pleistocene bed at Portrush, in the north of Ireland, as has
been noted by Mr. Smith, there are many species of land shells
fossil, in such a state and in such a locality, that a person un-
aware of their history would, without hesitation, have enume-
rated them as natives of the place where they are found. It is
remarkable, that among them there is not a single specimen of
Bulimus acutus or Helix ericetorum, now abundant alive in
the immediate neighbourhood of the bed.

All these modifying influences being taken into considera-
tion, it behoves us to be very cautious how we judge of the in-
fluence of geological and climatal causes on the distribution of
a species. The absence of a hill, a wood, a lake, or a ditch,
may cause the absence of many species, and lead us to attri-
bute their non-appearance in the district to a climatal cause,
when the presence of the necessary modifying influence might
have called them forth. It is only by a comparison of many
districts, and of the face of the country in each, that we can
hope to arrive at just conclusions ; and it is necessary in every
case to ascertain as far as we are able the circumstances under
which each species is found in other parts of the world, espe-
cially in Europe, ere we can argue fairly on its distribution ni
our own country.

II. — On the Distribution of Pulmoniferous Mollusca in the
various provinces of the British Isles.

Dividing the British Isles into ten zoological provinces,
we shall find that each presents certain features peculiar to
itself as regards the Pulmonifera inhabiting it. These peculi-
arities arise from the predominance of some one of the influ-
ences which I have enumerated. It would be very desirable
to consider the distribution in all the districts proposed by

K 2

132

REPORT 1839.

Mr. Brand in his papers on the statistics of British Botany; but
as yet the zoology of our country has not been sufficiently in-
vestigated, in many of our provinces, to warrant such a subdi-
vision. In the adoption of the following districts I have rather
followed zoological peculiarities than topographical limits.

I.
II.

III.

IV.

VI.
VII.
VIII.

IX.

Districts.

Primary Influences.

Secondary Influences.

Positive.

Negative.

Positive.

Negative.

The Channel Isles.
S.E. of England.

S.W. of England.

N.E. of England.
N.W. of England.
N. of Ireland.
S. of Ireland.
S. of Scotland.

N. of Scotland.

Shetland Isles.

Climate,
f Climate.
\ Structure.

Climate.

Structure,

Structure.

Climate.

Structure.

Marine.
Rivers, &c.

Marine.

Woods.
Marine.
Marine.
Marine.
Woods.

Marine.

J Absence of
t Canals, &c.

Structure.

Climate.

Clirnate.

Structure.

Climate.
r Climate.
\ Structure.

Climate.

Want of water
' in parts.

Elevation.

' Elevation.
Want of wood.
Want of wood.

District I. — There needs some apology for including the Chan-
nel Isles in the preceding table. Botanists and conchologists
have long been in the habit of enumerating their productions
as members of the British Fauna and Flora ; a better excuse,
however, is, that by considering their inhabitants, in conjunc-
tion with those more truly British, we are enabled to connect,
as it were, the natural history of our country with that of the
continent, and thus avoid limited and local notions. The
peculiarities of the first or more southern district are climatal ;
in this province we see an instance of positive climatal influ-
ence, and of the predominance of climate over geological struc-
ture. The islands are primitive, and, as far as rock goes, un-
favourable to the development of Mollusca; nevertheless, shells
rarely found in such situations, such as Helix variabilis and
striata, are there seen in great numbers. The scarcity of ponds
and lakes, and of water generally, accounts for the small list of
fresh-water Pulmonifera, viz. three Limnei, one Flanorbis, and
one Ancylus. The Limnei are L.pereger, L.palustris, and L.
minutus. In the island of Herm these are found in a situation
deserving of notice. Here and there, among the low sandy
banks formed by the sea, are springs of fresh water, forming
little pools, the bottoms of which are sandy. In these pools
we find the Limnei I have mentioned. The single Flanorbis
is P. nitidus. Amonji the Helices we find in this district two

ON BRITISH PULMONIFEROUS MOLLUSCA. 133

species which do not occur elsewhere in the British Islands,
and which may be considered indications of the positive in-
fluence of climate. They are Helix naticoides and Helix re-
velata. The total number of Pulmonifera, which I have ob-
served in Guernsey and Herm, is twenty-nine species. 1 doubt
not, on further investigation, half a dozen more may be added ;
but on the whole this district may be regarded as unfavourable
to the multiplication of species in consequence of structure, yet
favourable to the multiphcation of individuals in consequence
of climate. The fauna is nearly related to that of the opposite
coasts of France, if anything, a little more southern in cha-
racter.

District II. — In the second district, the south-east of Eng-
land, the influences of climate and structure may be regarded
as equally balanced. Here we only find Helix obvohita and
Helix li?nbata, which, as well as Clausilia ventricosa, may be
regarded as climatal species. The only known localities for
Clausilia Rolphii are in this district. Such land-shells as
frequent chalky soils abound. In common with the south-
west division, it furnishes Helix pomatia, Testacellus halio-
toideus, and Bulimus montanus. The Helix pomatia is by
many accounted an introduced species ; but when we consider
the partiality shown by that shell for the newer calcareous
strata in all parts of Europe, and the geological correspondence
of its British and continental habitats, I think there can be but
little question of its indigenousness. The influence of a great
river, such as the Thames, is more evident in the presence of
the freshwater Pectinibranchia than of peculiar Pulmonifera.
Planorbis corneus is chiefly found in this province. Helix
carthusianella has not been found elsewhere in Britain. Some
of the more northern species, such as Helix scar bur geiisis and
Clausilia dubia, are absent. It is possible the absence of the
rocks of the coal formation may cause the absence of several
Helices and Pupag in this district.

The Rev. Leonard Jenyns has favoured me with an excel-
lent manuscript list of the land and fresh-water mollusca indi-
genous to Cambridgeshire, one of the most northern portions
of this second province. The fauna of that county presents
some pecuharities, in consequence of the presence of large
tracts of fens, presenting features in common with the southern-
most part of the fourth district. The following analysis of the
localities of the Pulmonifera, enumerated in the catalogue of my
distinguished correspondent, will prove instructive: —

The total number of undoubted species is sixty- two. Of
these five are Limaces, one Vitrina, one Succinea, twenty-

134 REPORT— 1839.

three Helices, one Bulimus, two Achatinas, two Clausiliae, one
Balea, five Pupas, one Carychium, ten Planorbes, two Physag,
six Limnei, and two Ancyli. Of these, twenty-two species
are generally distributed throughout the county ; eighteen are
local, found at a few places only, and those not fenny ; seven
are local species, having fenny localities, and nineteen are spe-
cies found almost exclusively in the fen districts. Of the ter-
restrial species thirty-three frequent woods, gardens, hedges,
and bushy places ; four are found on heaths, dry banks, and
open places ; six in fenny districts, and one in cellars and
damp buildings. Of the aquatic species seventeen are found
in fens and low ponds, and four are not confined to the fens.
Associated with these Pulmonifera, are one Cyclostoma, one
Neritina (which is confined to the river Cam), two Valvatae,
three Paludinse, one Anodon, one Unio, three species of
Cyclas, and six species of Pisidium. In the list of Pulmo-
nifera is also included with a query the Physa alba, of which
Mr. Jenyns says he received a single specimen exactly accord-
ing with Turton's figure, from a deep drain in the heart of the
fens. " It was given me by a gentleman who was formerly
resident in the neighbourhood of the spot, and who observed
it with many others that had been thrown out with the mud
on the occasion of the drain being cleaned. Not aware at the
time of its being anything peculiar, only two or three spe-
cimens were brought away. I rather think the drain is
now filled up." Such accidents well deserve our attention,
frequently causing the destruction of perhaps the only locality
in a district of some rare aquatic species. There are certain
species, such as the Irish Limneus involutus, which are only
known in one or two limited localities. An accident, such as
that which destroyed this Physa, might render such local forms
altogether extinct ; and should it have been the fate of any
such extirpated species to have remained unrecorded, in case
it afterwards occurred fossil in a bed of fresh-water marl, a
dangerous geological fallacy would take place. Mr. Jenyns
notes another instance of the disappearance of an aquatic spe-
cies. Of Limneus glutinosus he writes, " Some years back
this species occurred in the utmost profusion in one marshy
spot not a mile from my house ; but it has since disappeared,
and I never observed it in any other locality."

District III. — Throughout a great part of the third or south-
western English district the negative influence of structure is
very evident, most especially in that portion of it where cli-
mate should exhibit its influence most forcibly, namely, the
counties of Cornwall and Devonshire. In these counties the

ON BRITISH PULMONIFEUOUS AJOLLUSCA. 135

primitive structure of the rocks, doubtless, limits the number
of species, but is overcome by the climatal and marine influ-
ences as respects the number of individuals. Several of the
species too are decidedly southern and climatal in character,
such as Helix pisana and Testacellus haliotoideus ; others
are western, as Bulimiis acutus. The naturalization of some
of the exotic Bulimi, such as B. decollatus and B, clavulus
in this district, is a further proof of climatal influence. In the
more eastern portions of the district, such as Dorsetshire, we
find a general correspondence as regards species with those
of the second district, doubtless dependent on a similarity of
geological structure. Thus we find the western limits of
Helix lapicida, H. pomatia, Limneus auricularius , and Pla~
7iorbis corneus, on the southern coast, on the confines of
Dorsetshire. The calcareous districts of Somersetshire and
Gloucestershire are more favourable for the production of
species, the catalogues of land and fresh-water mollusca in
those districts presenting a considerable increase over those of
Cornwall and Devon, dependent partly on geological causes,
and partly on the greater frequency of localities for aquatic
species. Throughout these counties the climatal influence is
equally evident. The lists of the th|ird province attain their
maximum in South Wales, evidently dependent on the pre-
sence of carboniferous strata in that locality. There, however,
climatal influence diminishes, and the Testacellus haliotoideus ^
so characteristic of that influence, disappears. In that portion
of the district we find one of the two localities for the rare
Succinea oblonga, which has been observed elsewhere in
Britain only in the south of Scotland, in a district of similar
geological structure. In the south-western province we find
also one of the few British localities for another rare shell,
the Pupa cylindrica, which was found by Mr. Jeffi-eys, who
has done much towards the investigation of the mollusca of
this part of Britain, in the neighbourhood of Bristol. The
scarcity of aquatic species in the primitive counties of the
third province is not attributed solely to the scarcity of water,
but also to the nature of the sediment in pools and streams
of primitive countries being evidently unfavourable to the mul-
tiplication of Mollusca.

District IV. — No part of Britain is richer in Pulmoniferous
Mollusca than the north-eastern division of England. The New-
castle list alone, thanks to the researches of Mr. Alder, enu-
merates sixty-seven species. That of Scarborough, a district
thoroughly investigated by Mr. Bean, exhibits no less than
seventy-four. The former is a carboniferous neighbourhood,

136 REPORT — 1839.

the latter coralline oolite and chalk. We must attribute the
richness of this district in species to the predominance of the
positive geological influence. In the neighbourhood of Sun-
derland, in the magnesian limestone, sixty-four species occur.
Of these the following are considered peculiar to the limestone
in that locality : Helix glabella, pulchella, rupestris, and
variabilis, Clausilia dubia, Balea fragilis, Pupa pygmcEa,
and Acme lineata. Judging from Mr. Bean's list, the calca-
reous strata of the neighbourhood of Scarborough must be
especially favourable to the variation of species. Thus he
mentions 152 varieties of Helix hortensis, fifty-eight of his
Helix pullata (a white-mouthed form o^ Helix hortensis), 226
of Helix nemoralis, and twenty-one of its variety, Helix nota-
bilis. Among the rarities of the north-eastern district. Pupa
alpestris, Pupa anglica, Helix scarburgensis and excavata,
and Planorbis IcEvis are conspicuous. In this district we find
the northernmost British localities for Helix carthusiana and
lapicida. Acme lineata, Clausilia laminata, dubia, and ventri-
cosa, Planorbis corneus, and Limn eus glutinosus ; also for Ci/-
clostoma elegans among the terrestrial Pectinibranchia. Dr.
Greville has communicated the remarkable fact, that the Helix
aspersa, so universal in England, is absent from the neigh-
bourhood of Craven in this province.

In certain localities, MoUusca, generally distributed in most
places without reference to geological structure, are confined
to particular strata. This is remarkably shown in the follow-
ing list of species observed by Mr. Bean to be peculiar to the
calcareous strata in the neighbourhood of Scarborough : Helix
ericetorum, variabilis, umbilicata, caper ata, radiata, pulchella,
and lapicida ; Bulimus obscurus. Achat ina acicula, Azeca
Matoni, Clausilia laminata and rugosa, Balea fragilis, Pupa
umbilicata, marginata, and pusilla ; Helix carthusiana and
Helix umbilicata confined to the chalk. In the neighbourhood
of Bamborough Helix caperata, and H. variabilis are found
together on trap, an unusual locahty for the latter species.

District V. — The fifth or north-western division of England
is similar in character to the fourth, though not so rich in spe-
cies, those of the chalk and oolite being absent. The rarer
species, found in the carboniferous strata of the last district,
are found also in similar localities in this. The new red sand-
stone, constituting a large portion of this division, exercises no
perceptible influence in favour of the increase of species. The
presence of Bulimus acutus indicates the western climatal in-
fluence. Planorbis corneus is absent from the waters, and
Limneus stagnalis appears for the last time on the western

ON BRITISH PULMONIFEROUS MOLLUSCA. 137

coast of Britain. Acme lineata extends to Preston, the most
northern hmit, by the way, of Paludina vivipara. Pupa al-
pestris was first observed in Lancashire. In the slaty districts
of North Wales and Cumberland the number of species is less
than in other parts of the district. In the Isle of Man, which
I append to this province, we find but a small list of species.
Plcuiorbis marginatus is altogether wanting in that island.
The marine influence is evident there and in North Wales.
Helix ericetorum is, in this province, a sea-side species. On
the whole, this is the part of England least favourable to the
multiplication of species, and where the influence of climate is
either negative or neutralized by geological structure or ma-
rine influence.

Districts VI. and VII. — In Ireland we see the climatal influ-
ence predominating in the extreme south, but counteracted by
geological structure, the geological influence predominating in
the extreme north, but counteracted by the negative influence of
climate ; whilst the greater part of the intermediate districts pre-
sents the influence of carboniferous strata, modified by peculia-
rities of climate. The presence of Testacellus in the south is
proof positive of climatal influence, as also is that of Helix
pisana in the neighbourhood of Dublin. Generally speaking,
however, the Pulmonifera of Ireland correspond to those of
the extreme north of England and the south-west of Scotland.
Ireland presents us with one aquatic species peculiar to it, the
Limneus involutus, hitherto unobserved in any other part of the
world, and by far the most remarkable of all the species of its
genus. The number of true species of Pulmonifera found in
Ireland is 75 ; thus exceeding Scotland by four, but falling 20
short of England. On the distribution of these, my friend Mr.
Thompson, of Belfast, has favoured me with the following
notes, as well as all the other information I possess on this divi-
sion of the Irish Fauna. The difference in number between the
species found on the north and south of Ireland is trivial as
far as known, and cannot be stated with certainty. Of species
found in the more southern half of Ireland, and not in the
north, the following may be mentioned : Testacellus haliotoi-
deus (var. scutulum), at Youghal ; Helix globularis, Helix
striata, Achatina acicula, and Limneus involutus. Clausilia
bidens, which has been obtained in Cavan and Fermanagh, and
Planorbis Icevis, common to Down and Antrim, have not been
observed in the south. Helix pisana is only found in the
county of Meath. Planorbis cor?ieus is found only towards the
centre (as to latitude) of Ireland. The chalk district of the
north seems to have little influence on the species of the Pul-

138 REPORT — 1839.

monifera, although it has much in increasing the number of
the species indigenous to it. The difference between the cata-
logues of Mollusca pulmonifera of Cork, Dublin and Belfast,
is not great either as to number or otherwise. Helix glabella,
common about the two former, is not obtained near Belfast.
Helix pomatia, carthusiana and lajncida, and Limneus elon-
gatus, appear to have found their way into the Irish catalogues
by mistake. In Ireland the distinction between the Faunas
of the eastern and western coasts is not so marked, as respects
the Pulmoniferous Mollusca, as in England.

District VIII. — The southern half of Scotland might be di-
vided into two great geological districts, the one favourable and
the other unfavourable to the development of its Fauna. The
unfavourable portion is the southernmost, and consists chiefly
of slaty rocks. The other division, extending to the edge of the
Grampians, is mainly composed of rocks of the coal formation,
and of trap, both favourable to the production of mollusca.
But climate here almost neutralizes the geological influence ;
the effect of which may, however, be still recognised in the
multiphcation of individuals on a genial soil. For the last
time in Britain we meet with Succinea oblonga, Helix fusca,
globularis, pura, aculeata, pygmcea and striata, Bulimus ob-
sciirus, Achatina acicula (these exceeding rare), Pupa anglica,
substriata, pygmcea, edentula and pusilla, Azeca tridens, all
the species of Planorbis and of Physa, and all the Limnei except
Limneus pereger and Limneus minutus, as also Ancylus
lacustris. The chief rarities of the south of Scotland are
Succinea oblonga and Pupa cylindrica ; the former found on
carboniferous sandstone, the latter on trap, and neither of
them as yet observed in the north of England. In the woods
of the district we find Helix scarburgensis and fiisca, Pupa
edentula, and occasionally Bulimus obscurus. The portions
most prolific in species are the neighbourhoods of Edinburgh,
Berwick, and Glasgow, partly, without doubt, in consequence
of the woods near those towns. There is but little difl^erence
between the Pulmonifera of the eastern and western divisions
of the district ; but among the fresh-water Pectinibranchia we
find Paludina impura on the western coast only. The south
of Scotland may be regarded as upland.

District IX. — Climate sways the distribution in the ninth di-
strict. The hospitality of the Highlands does not extend to snails.
The bleak granite mountains, with their scant vegetation, hold
out but few temptations to the Pulmonifera. The species are
few, and the specimens are few. On the trap and under the
marine influence, in some of the Western Isles, they are some-

ON BRITISH PULMONIFEROUS MOLLUSCA. 139

what more numerous than elsewhere. Some rare species,
however, occur, with several of the scarcer forms ; Helix
fulva, scarburgensis and excavata, have lately been added to
the list by Mr. Alder. Helix crystallina is not uncommon ;
Helix ericetorum and Bulimus acutus abound on sandy soil in
the outer Hebrides. Pupa palustris and Helix radiatula
were found on the islands opposite Oban by Mr. Jeffreys, and
Pupa cylindrica in Skye (on trap) by Mr. Macaskill. On
the mountains Helix alliaria is not rare.

District X. — Only five species oi Pulmoniferous Mollusca in-
habit the Shetland Isles. These five are Arion ater, Limax cine-
reus, Vitrina pellucida, Helix alliaria and Limneus pereger^
all species common to the whole of the north of Europe, and
extending their range to Greenland. The geological struc-
ture of these islands being primitive is unfavourable to the
development of species ; but I regard the distribution as
wholly climatal in this, the most northern province, inasmuch
as it is in no way influenced by the tracts of limestone which
occur in certain localities in Shetland. Individuals are as
scarce as species ; the only animal of those enumerated at all
plentiful is Avion ater.

In the first of the two following tables the numbers of the
species of eachgenusfoundin the various districts are exhibited.
For the first province the materials were derived from per-
sonal research ; for the second, from published lists and com-
munications from Mr. Jenyns and Dr. Stanger ; for the third
and fifth, from published lists and personal observation ; for
the fourth, from the published lists of Mr. Alder, and communi-
cations from that gentleman, Mr. Bean and Dr. Greville. The
sixth and seventh districts yielded their numbers through the
medium of my friend Mr. Thompson, of Belfast ; the eighth
and ninth from personal observation, published lists, and
communications from Sir William Jardine, Dr. Johnston, and
Mr. Smith of Jordanhill, and other gentlemen. The tenth I
investigated myself.

In the second table, the distribution of the species on the
various strata is exhibited. If the pectinibranchons Mollusca
had been added, the preponderance of the cretaceous and
oolitic strata would have been much more evident, and there
are several species at present known entirely as inhabitants of
the carboniferous rocks, which, I doubt not, will also be found
on the former, or have been confounded with other species.

In both tables I have omitted all forms which I could not
regard as true species, or the indigenousness of which has
been questioned on good grounds.

140

REPORT — 1839.

Table I.

GENERA.

II.

III.

IV.

VI. & VII.

VIII.

IX.

Limax

Testacellus...

Vitiina

Helix

29
2

24
2

Succinea ....

Bulimus

Achatina

Acme

—

1
1

Azeca

Pupa

Clausilia

Balea

Carychium...

—

Limneus . ...

Planorbis ...

Physa

Ancylus

Total ...

1
30

Table

[I.

Rocks

in order of their

Influence.

.><•

_3
IS

c
S

S
>»

<
1

Cu,

eq
1

(J
1

h4
7

<5
2

Cretaceous and )
Oolitic 5

Carboniferous }
Rocks and Trap J

Tertiary

Saliferous

1
1

1
2

8
2

1
1

6
3

7
5

65
44

Slates

Granite & Gneiss

III. — 0;2 the relations of the British Pulmoniferous MoUusca
to those of Europe generally, and the distribution of the
more remarkable species.

To compare the distribution of Pulmonifera in Britain with
their distribution on the Continent, or even to ascertain the
European range of British species, is by no means an easy
task. The difficulty chiefly arises from the want of agreement
between the writers of different countries. Almost every land
and fresh-water shell has half a dozen synonyms, and every
local catalogue presents us with names (not species) peculiar
to itself. The habit of changing names, — I had almost said, —
wantonly, — has been indulged in to an unwarrantable extent
among Malacologists, especially writers on the order of ani-

ON BRITISH PULMONIFEROUS MOLLUSCA.

141

mals under review. Unfortunately a great part of the Euro-
pean species were named contemporaneously by Montagu in
England, and by Draparnaud in France, and several years
elapsed before it was possible to compare their nomenclatures.
In the mean time that of the former had become universal
among British authors, and that of the latter among Conti-
nental, and much confusion has arisen in consequence. Of late
there has been a tendency among British authors to adopt
Draparnaud's names, and among Continental writers to use
those of Montagu. Another cause of difficulty has arisen from
the very different views entertained by authors as to the spe-
cific claims of the forms they describe, some elevating every
little variation to the rank of a species, others attempting defi-
nitions more in accordance with the philosophy of natural
history. Writers acquainted only with the animals of their
own country or district, are especially apt to blunder on this
point, and to constitute every local variety a species. The
error is luckily on the safe side : it is better that every varia-
tion should be dignified as a species for a time, than that any
one form be past over. In the following table, exhibiting a
comparison of the principal published European lists, allow-
ances must be made for the above reasons, though to a certain
extent I have endeavoured to correct it. I may mention that
Krynicki's Russian list includes the Caucasus. The French
list may be regarded as slightly over-stated, several of Mi-
chaud's species being probably supposititious. Deduct one
Limneus from the British list, and there remain the numbers
for England alone.

British Isles

Scotland

France (Michaud) ...

Sweden (Wilson)

Brabant (Kickx)

Switzerland (Char-"1

pentier) J

Italy, exclusive of Si- "1

oily (Jan) J

Thetwo Sicilies (Phi-]

lippi) J

Germany (Pfeiffer) ...
Russia, with the Cau- 1

casus (Krynicki) J

H >iE

CM u

12 5
1

25 11
64
12 6

2111

i
1310

.j.

1517
1615

5
10

Ph Cl,

112
13 2

142 REPORT — 1839.

The Limacidae of the Continent cannot well be compared
with those of Britain, as they have been but imperfectly ob-
served in most countries, and in many Faunas omitted altogether.
France and Sweden appear to excel us in the number of spe-
cies ; but it is probable we possess several unnoticed forms.
Of the two species of Testacellus generally enumerated as
British, one, the T. Maugei, found near Bristol, was undoubt-
edly introduced ; it is a native of the Canaries. The other
is a true native, found generally throughout the south-western
countries of Europe, the distribution of which may be regarded
as regulated by climate. Our single species of Vitrina is a
shell found in most parts of Europe, in all the northern di-
stricts especially. It occurs also in Greenland. Its distribu-
tion appears to be essentially climatal, as is the case with the
genus generally, of which the European forms are the northern
representatives, the true centre of the genus being near the
tropics. The distribution of the genus Succinea appears to
be similarly regulated ; but our common British species, the
Succinea amphibia (including S. gracilis or Pfeifferi), is much
more widely spread than any Vitrina, being found throughout
Europe, from Archangel downwards, in North America, and
in North and South Africa, as far as the Cape of Good Hope.
The Succinea oblonga has also a very wide range. In Europe
it occurs in Britain, Denmark, France, Germany, and Swit-
zerland, and is found at Lima, Vera Cruz, and the Cape of
Good Hope.

In the number of native species of the genus Helix, England
exceeds Scandinavia by 17 species, and Brabant by 15, but
yields to the other European lists of equal importance, espe-
cially to those of the southern countries. France exceeds
Britain by no less than 41 species. The only species which
can be looked upon as certainly peculiar to the British Isles
is the Helix fusca of Montagu ; the Helix scarburgensis,
till lately considered as exclusively British, having been
found in Northern Germany. It is difficult to say whether any
of the Helices allied to H. nitens are confined to Britain,
so much confusion prevailing in the Continental lists as regards
that tribe. Thus in no foreign catalogue do we find Helix
alliaria, though without doubt it occurs in most parts of Eu-
rope. I have collected specimens in France and elsewhere.
It extends to Greenland. This interesting subdivision of the
genus prevails most in the moor-land or elevated districts of
England. We find such to be the case also abroad. Helix
cellaria is found throughout Europe, and the countries bor-
dering on the Mediterranean. Helix nitida extends its range

ON BRITISH PULMONIFEROUS MOI.LUSCA. 143

to the United States and to the West Indies. The allies of
Helix variabilis are extensively distributed. Helix variabilis
itself is found through most parts of Europe, the Mediterranean
countries, and the United States of America; and Helix pisana
has an equally extensive range. The hispid Helices are gene-
rally distributed through Europe. Much confusion, however,
exists in lists as regards the immediate allies of Helix hispida.
The Helicogenae of Ferussac have great ranges. The com-
mon snail of our gardens, Helix aspersa, is equally common in
the gardens of Southern Europe, and is found also in parts of
Asia, Africa, and North and South America, Helix hortensis,
nemoralis and arbustorum, inhabit most parts of Europe ; and
Helix pomatia has nearly as great a range as Helix aspersa.

Bulimus montanus, with us an inhabitant of the plain di-
stricts of southern England, on the Continent inhabits subalpine
districts, chiefly where limestone prevails. Our Bulimus ob-
scuriis is found throughout Europe. Bulimus acutiis, with us
usually an inhabitant of the sea-side, is found inland in Switzer-
land. On the shores of the Mediterranean it abounds, and
assumes many variations of form and colour, along with its
near ally Helix conoideus, near which it should probably be
placed, rather than with the Bulimi. Both our Achatinas
are natives of most parts of Europe, and the A. acicula is
found in Northern Africa. As we approach the tropics the
forms of this genus multiply. Our species belong to the sec-
tion Cionella (Jeffreys), the centre of which may be regarded
as placed in the islands of the north-west coast of Africa.
Azeca Matoni is a native of Central Europe as well as of Bri-
tain. The number of British species of Clausilia is but a
small proportion of this large and interesting genus, the varied
forms of which abound in the countries of Eastern Europe
and the neighbouring parts of Asia. One of our native forms,
however, the Clausilia Rolphii of Leach, is confined to Bri-
tain, and with us is only found in the south-east of England.
Our other species are found in most of the countries of the
Continent. The Balea fragilis is frequent in Northern and
Central Europe, and is the only European species. Other
forms of the genus occur in the West Indian Islands. The
genus Pupa affects mountainous districts, and species abound
in the Alps, where we find many eccentric and abnormal forms
of the genus. France, Russia, and Austria exceed us in the
number of species, France doubling our number. One of our
Pupae, the Pupa anglica, has never been found out of the
British Islands ; the others are generally distributed through
Europe, and the Pupa umbilicata inhabits Mount Atlas.

144

REPORT — 1839.

• The distribution of the Aquatic Pulmonifera is much more
equal than that of the Terrestrial, as might be expected from
the nature of the element in which they live. In Limneus,
Planorbis, Physa, and Ancylus, the differences between the
European lists are very slight, and the species are generally
identical. The himneus involutus of Harvey would appear to
be the only species peculiar to Britain, not having been found
elsewhere than in its Irish locality. Some of our native spe-
cies have very wide ranges, Limneus stagnalis extending from
Cachemyr to the United States, and Limneus palustris occur-
ring in most parts of the world. Limneus per eg er is also very
widely distributed. Limneus minutus is found in very elevated
situations in the Alps, and in low ground in the north of
Africa. The genera Limneus, Physa, and Planorbis, are
found to inhabit most parts of the world.

Table
Of the Species of Pulmoniferous Mollusca inhabiting the Bri-
tish Isles, and their Geographical Distribution.

Genera and Species.

British Distribution.

General Distribution.

LiMAX, Linn.

[Arion.]

Empiricorum, Fer.

I.-X.

All Europe, Teneriffe.

hortensis, Fer.

[LiMAX.]

11.— vin.

Central& Northern Europe.

cinereus, Linn.

I.— X.

Europe, Teneriffe, Algiers.

variegatus, Fer.

II.

Europe, Cyprus, U. States.

agrestis, Linn.

I.— VIII.

All Europe, Teneriffe.

Sowerbii, Fer.

II.. VII.

France.

brunneus, Drap.

VIIL

France.

II.

Testacellus, Cuv.

haliotoideus, Drap.

L— in., VII.

S. W. of Europe.

scutulum, Sow.

II., VII.

III.

ViTRiNA, Drap.

pellucida, Miill.

I.— X.

N.& C.Europe, Greenland.

Drapernaldi, Jeff.

Diapliana, Jeff.

Dilwynii, Jeff.

IV.

SucciNEA, Drap.

amphibia, Drap.

I.— IX.

All Europe, N. America,

i§

gracilis, Alder.
(Pfeifferi), Rossm.

Africa, Western Asia.

oblonga, Drap,

III., VIIL

N.& C. Europe, S. America,
Cape of Good Hope.

Helix, Linn.

pomatia, Linn.

II., IIL, ?

C. & S. Europe, W. Asia,
N. Africa, S. America.

arbustorum, Linn.

II.— IX.

N. E. and C. Europe.

aspersa, Mull.

I.-IX.

C.& S. Europe, Asia, Afri-
ca, N. & S. America.

TABLE {continued)..

145

Genera and Species.

British Distribution.

General Distribution.

naticoides, Drap,

S. Europe, N. Africa.

nemoralis, Linn.

I.-IX.

All Europe.

hybrida.

hortensis, Linn.

I.-IX.

All Europe.

limbata, Drap.

Central Europe, Rhodes.

carthusiana, Drap.

n.-iv.

C. & S. Europe, N. Africa,
Caucasus.

carthusianella, Drap.

II.

C. S.& E.Europe, W. Asia.

obvoluta, Mull.

II.

C. Europe, Sweden.

glabella, Drap.

II,— v., VII.

C. Europe.

depilata, Pfeiff.

I.— VIII.

All Europe.

12§

concinna, Jeff.

hispida, Mull.

I.-IX.

N. and C. Europe, Tauria.

13i

sericea, Mull.

globularis, Jeff.

I.— VIII.

N. and C. Europe.

revelata, Fer.

France.

fusca, Mont.

li.— VIII.

excavata, Alder.

IV., v.. VII., VIII.

lucida, Drap.

iL-vin.

N.C.& E.Europe, Algiers.

niiidula, Drap.

L-IX.

All Europe.

Helmii, Gilb.

19i

glabra, Studer.

radiatula, Alder.

II.— IX.

France.

alliaria, Miller.

L-X.

N.& C.Europe, Greenland.

cellaria, Mull.

I.— IX.

All Europe, W. Asia, N.
Africa, Canaries.

pura, Alder.

II., IV.— vin.

Central Europe.

23^

nilidosa, Fer.

crystallina, Mull.

II.-IX.

All Europe.

fulva, Drap.

II.— IX.

N. and C. Europe.

25i

Mortoni, Jeff.

scarburgensis, Bean.

IV.— IX.

North of Germany.

aculeata, Mull.

II.— VIII.

N. and C. Europe.

pulchella, Mull.

II.— IX.

N. & C. Europe, U. Stales.

pygmsa, Drap.

II.— IV., VT.-VIIL

N. and C. Europe.

rupestris, Drap.

III.— VIII.

N. and C. Europe.

rotundata, Mull.

I.-IX.

All Europe.

striata, Drap.

I.— VIIL

All Europe, W. Asia.

variabilis, Drap.

I.— VII.

C. & S. Europe, N. Africa,
W. Asia, N. America.

ericetorum, Linn.

I.— IX.

All Europe, W. Asia, Egypt.

pisana, Mull.

III., VIL

S. Europe, W. Asia, N. A-
frica, N. America, United
States, Canaries,

lapicida, Linn.

II.-IV.

All Europe.

VI.

BuLiMUs, Brug.

acutus, Mull.

I., III., v.— VII., IX.

C. & S. Europe, N. Africa,
W. Asia, N. America.

montanus, Drap.

II.— III.

C. and E. Europe.

obscurus, Mull.

II.— VIIL

N. C. & E. Europe, Cau-
casus.

VII.

AcHATiNA, Lam.

acicula, Mull.

II.— IV., VIL, vin.

All Europe, N. Africa,
Caucasus.

lubrica, Mull.

I.— IX.

All Europe.

VII.

AzECA, Leach.

Goodalli, Fer.

II._V., VIIL

Germany, France, Pyrenees.

l^'M).

146

TABLE {continued).

Genera and Species.

British Distribution.

General Distribution.

VIII.

Clausilia, Drap.

bidens, Mull.

II.-VIL

All Europe.

ventricosa, Drap.

1 1.- IV.

Central Europe.

Rolphii, Leach.

II.

dubia, Drap.

IV.

Central Europe.

rugosa, Drap.

I.— IX.

All Europe.

5§

Everettii, Miller.

IX.

Balea, Gray.

fragilis, Drap,

L-VIIL

N. C. and E. Europe.

Pupa, Drap.

umbilicata, Drap.

I.-IX.

All Europe, Caucasus, N.
Africa.

marginata, Drap.

L-VIIL

Europe, Caucasus.

anglica, Fer.

IV., VL, VIIL

secale, Drap.
[Vertigo.]

II., III., V.

All Europe.

edentula, Drap.

II.— VIIL

N. and C. Europe.

cylindrica, Fer.

III., VIIL, IX.

Central Europe.

pygmaea, Drap.

II.-VIII.

N. and C. Europe.

alpestris, Fer.

IV., V.

Central Europe.

substriata, Jeff.

II.— VIIL

Central Europe.

palustris, Leach.

II.— IX.

Central Europe.

pusilla, Mull.

IL— VIIL

Europe.

angustior, Jeff.

II., III., VII.

France.

Carychiom, Mull.

minimum, Mull.

IL— IX.

N. E. and C. Europe.

XII.

Acme, Hartmann.

lineata, Drap.

II.-VIL

Central Europe.

XIII.

Planorbis, Mull.

corneus, Linn.

II.-IV., VII.

Most parts of Europe.

marginatus, Drap.

II.-VIIL

Most parts of Europe, Al-

2§

r/ionibeus, Turt.

giers, Caucasus.

2§

tur nidus, Jeff.

rarinatus, Mull.

IL— VIIL

Europe generally, Caucasus

discifarmis, Jeff.

vortex, Mull.

TT._VTIL

N. & C. Europe, Volhynia.

spirorbis. Mull.

II.— VIIL

Most parts of Europe.

Ic-evis, Aid.

IV., VI.

France.

albus. Mull.

II.-VIIL

N. and C. Europe.

defurmis. Lam.

glaber, Jeff

contortus, Linn.

IT.— VIIL

N. E. and C. Europe.

lineatus, Walker.

IL, VL, VIL

Europe, Caucasus.

nitidus, Mull.

I.— VIIL

Europe.

imbricatus, Mull.

II.-VIIL

Europe.

XIV.

Physa, Diap.

fontinalis, Linn.

IL— VIIL

N. and Central Europe.

hypnorum, Linn.

N. and Central Europe.

XV.

LiMNEUS, Drap.

stagnalis, Linn.

IL, IV.— VIIL

Throughout Europe, Asia,
N. America.

palustris, Linn.

II._VIII.

All Europe, N. America.

minutus, Drap.

I.-IX.

All Europe, W. Asia, N.
Africa, Coquimbo.

elongatus, Drap.

IL, IV.— VIIL

Europe.

pereger, Drap.

I.— X.

All Europe.

ovatris, Drap.

TABLE {continued).

147

Genera and Species.

British Distribution.

General Distribution,

lineatus, Bean.

lacustris, Leach.

acutus, JefF.

auricularius, Linn.

ir.-viii.

All Europe, Cachemyr.

involutus, Harvey.

VIL

glutinosus, Mull.

IL, IV.

Central Europe.

XVI.

Ancylus, Geoffrey.

fluviatilis, Mull.

L— IX.

All Europe, N. Africa.

lacustris, Mull.

II,— VIII.

All Europe,

Note. — The preceding table is based on Mr, Alder's Catalogue, in the Second Volume
of the Magazine of Zoology and Botany, The list has been submitted to him,
and I am happy to say the alterations have received his sanction.

METEOROLOGICAL OBSERVATIONS AT PLYMOUTH. 149

Third Itepori on the Progress of the Hourly Meteorological
Register at the Plymouth Dock-Yard, Devonport, Lat.
50° 21' 'N. Long. 4° 7' W., carried on at the request of the
British Association, under the direction of Mr. W. Snow
Harris, F.R.S.

1. The Hourly Meteorological Observations, which the Council
of the British Association did me the honour to place under
my care, have been continued without interruption from the
early part of the year 1832. Since that time about 70,000
hourly observations on temperature have been completed, and
the results of several years printed in the Reports of the Asso-
ciation for 1835 and 1838.

Similar observations of the barometer and moistened thermo-
meter commenced in January 1837, and briefly mentioned in
the Eighth Report of the Association, are now complete for
three years. In the present communication I propose to no-
tice some of the principal results of these registers.

The registers of the anemometers invented by the Rev. Mr.
Whewell and Mr. Follett Osier, of Birmingham, although care-
fully attended to, have not been completed for a sufficiently
long period, owing to many difficulties and interruptions inci-
dental to the bringing of these instruments into operation. I
am not enabled, therefore, to say more at present of Mr.
Whewell's instrument than has already appeared in my former
Report.

The observations hitherto registered by Mr. Osier's anemo-
meter have been tabulated by him in conjunction with those
registered at Birmingham ; they will appear in a separate form.
We may, however, now look forward to include the results of
all the instruments registered here in one general scheme.

Hourly Register of the Barometer.

2. In the three following tables will be found the principal nu-
merical results for the years 1837, 1838, and 1839, comprising
the mean hourly and monthly pressures, as also the mean
hourly pressures, for the four seasons, and for each six months
of summer and winter. From these we may obtain —

1st, The mean pressure.

2nd, The times of the day at which the mean pressure oc-
curs, and the mean daily course of the atmospheric tides, as
indicated by the hourly oscillation of the barometric column^

150

REPORT 1839.

3rd, The mean pressure of different seasons, including
spring, summer, autumn and winter, and of summer and win-
ter in periods of six months each.

4th, The course of the atmospheric tides in different seasons,
and the times of the day when the mean pressure occurs in
each.

5th, The average monthly pressure and periods of the year
at which the mean pressure occurs.

6th, The relation between the mean pressure of the twenty-
four hours, and that of any given hour or pair of hours.

3. Table I. Plate V.

Containing the Mean Hourly Pressures for each of the Years
1837, 1838, 1839, together with the Mean of these years ;
from 26,280 observations, at 75 feet above the mean level of
the sea, reduced to 32° of Fahrenheit's scale.

The periods of maxima are denoted by the sign + , the minima
by the sign — , and the mean by a *.

1837.

1838.

1839.

Mean ofthe 3 years

A.M. I

29-8719

*29-7565

#29-7768

29-8017

^29-8696

29-7547

29-7735

*29-7993

29-8626

29-7518

29-7688

29-7944

29-8608

29-7507

29-7670

29-7928

-29-8606

-29-7507

-29-7670

-29-7928

29-8619

29-7552

29-7710

^29-7960

29-8666

#29-7585

29-7755

29-8002

*29-8706

29-7615

*29-7772

29-8032

29-8717

29-7637

29-7790

29-8048

-J- 29-8732

+29-7645

+29-7807

+29-8061

29-8720

#29-7627

29-7788

29-8045

^29-8663

29-7587

29-7755

29-8002

P.M. 1

29-8627

29-7540

*29-7705

29-7957

29-8580

29-7517

29-7670

29-7922

29-8567

29-7500

29-7657

29-7908

-29-8558

-29-7475

-29-7652

-29-7895

29-8597

29-7532

29-7685

29-7938

29-8629

#29-7557

29-7725

29-7970

,29-8679

29-7610

29-7770

*29-8019

29-8740

29-7645

*29-7798

29-8061

29-8779

29-7672

29-7832

29-8094

+29-8792

+29-7665

+29-7840

+29-8099

29-8790

29-7665

29-7822

29-8092

29-8783

29-7639

29-7775

29-8065

29-8675

29-7579

29-7743

29-7999

Note. — The * indicating the Mean Pressure is placed between the hours at
which the mean occurs when the mean does not correspond to the pressure of
either.

Table II. Plate VI. Showing the Mean Hourly Oscillation
of the Bavometer in the Six Months of Summer and the Six
Months of Winter, from 26,280 observations reduced to 32°
of Fahrenheit's scale.

Hours.

Summer Months.

Winter Months.

1 A.M.

*29-789

29-813

29-785

*29-811

29-785

29-806

-29-781

-29-804

29-781

29-804

^29-783

29-809

29-788

*29-812

29-790

29-816

29-791

29-818

+29-792

+29-819

29-791.

29-818

*29-788

*29-812

1 P.M.

29-785

29-806

29-781

29-804

29-780

29-799

-26-778

29-860

29-782

-29-805

29-785

29-808

*29-789

*29-815

29-793

29-819

29-796

29-824

+29-797

+29-822

29-796

29-822

29-793

29-821

Mean 29-787

Meaa 29-811

Table III. Plate VII. Showing the MeanHourly Height of the
Barometer for each of the Seasons, in periods of Three
Months each , reduced to 32° ; from 26,280 hourly observations.

Hour.

Spring.

Summer.

Autumn.

Winter,

1 A.M.

^29-824

29-835

*29-743

29-803

29-820

*29-830

29-741

*29-803

29-814

29-829

29-739

29-799

29-814

29-825

-29-737

29-795

-29-814

-29-824

29-738

-29-794

^29-820

29-826

^29-740

29-798

29-824

*29-831

29-745

^29-801

29-824

29-832

29-740

29-808

29-826

29-831

, 29-752

29-810

+29-826

,29-834
+29-834

"l"29-750

+29-813

29-826

29-748

29-810

*29-823

29-833

^29-744

*29-801

iF.M.

29-821

^29-831

29-739

29-792

29-819

29-830

29-733

29-787

29-815

29-828

29-733

-29-783

-29-814

29-825

-29-732

29-787

29-816

"29-825

29-739

29-794

^^29-818

29-827

*29-744

^29-799

29-825

*29-829

29-749

29-805

29-832

29-835

29-752

29-807

,29-836
■T"29-836

29-839

,29-754

29-808

,29-841
■^29-841

+29-753

29-809

29-834

29-752

,29-810

29-842

29-836

29-751

+29-810

29-823

29-831

29-744

29-801

152

REPORT — 1839.

Table IV.
Showing the Mean Monthly Pressures for the Years 1837,
1838 and 1839; together with the Mean of these years,
reduced to 32° of Fahrenheit.

January ...
February . . ,

March

April

May

June

July

August ..
September
October ..
November
December

Mean

1837.

29-899
29-879
29-932
29-757
29-886
29-875
29-871
29-841
29-745
30-043
29*832
29-855

29-758
29-424
29-751
29-774
29-763
29-757
29-899
29-848
29-858
29-887
29-398
29-981

29-7581

29-929
29-933
29-719
29-975
29-854
29-762
29-749
29-882
29-516
29-858
29-561
29-557

29-7745

29-862

29-745*

29-801

29-835

29-834

29-798

29-840

29-857

29-706

29-929+

29-597-

29-798

29-800

Horary Oscillation.

4. The results given in Table I. and Plate V. show, that the
mean hourly pressure, Uke that observed between the tropics
and in other parts of the world, is subject to a peculiar oscil-
lation, producing two atmospheric tides in twenty-four hours,
thereby indicating some general law of our planet of consider-
able interest, and probably of great practical consequence to
Meteorology.

This result is so decided that it becomes apparent with singu-
lar regularity through each successive year, in the midst of acci-
dental fluctuations and casual disturbances of very considerable
amount. In Table I. will be found collected the mean hourly
pressures for the years 1837, 1838 and 1839, together with
the mean result of those years reduced to 32° of Fahrenheit by
Professor Schumacher's tables. These results are shown on
a proportionate scale in Plate V.

5. In laying down the delineations given in this and the suc-
ceeding plates, the mean points were first marked off, and then
a continuous waving line run through them so as to include the
greatest number. It will be found that the deviations are
few, and for the most part inconsiderable ; almost all the points
falhng within a continuous and fair curve ; where they do not
so coincide, the points of observation are denoted by a small
star.

6. The mean pressure in this latitude at 32° of Fahrenheit's
scale and at 75 feet above the level of the sea, deduced from

MKTEOROLOGIGAL OBSERVATIONS AT PLYMOUTH. 153

26,^280 hourly observations, in the three years above men-
tioned, appears to be 29,800 very nearly.

7. The barometric curve, indicating the atmospheric tides, is
on this line four times in the day, viz. at I'SO a.m., at 7 a.m., at
mid-day, or 12 noon, and at 6'30 p.m.

The pressure, having reached a minimum at 4 a.m., continues
to ascend for two hours, when it crosses the hne of mean press-
ure at 7 A.M., and ascending for the next three hours, reaches
its maximum at 10.

This morning tide* begins now to recede, and again de-
scending for two hours crosses the line of mean pressure at 12
or mid-day ; from which, continuing to descend for four hours
more, it reaches a minimum at 4. The evening tide begins now
to show itself; it ascends for two hours and a half, being on
the line of mean pressure at 6'30 p.m., whence, continuing its
ascent for three hours and a half, it attains its maximum at
10 P.M. At this point it again turns, and descending for three
hours and a half, reaches the point of mean pressure between
12 and 1 a.m., whence it passes in the succeeding two hours
and a half to its minimum at 4.

There are consequently, as in the afflux and reflux of the
sea, two tides in twenty-four hours.

8. The principal elements of these tides are as follows :

Table V.

Morning.
Min. 297928 at 4 A.M.

Max. 29-8061 at 10 A.M.

Mean 297999 at 7 A.M.
^tfo^'fS'?^' IoIm: } -0^33 Tin,e 6 hours.
^ P^rlssuVe^l.!..™. } '""^l Time 3 hours.
^PressuJ;'".l. °.*!..?!!!.!.'! } '^^^^ 'T''"^ 3 hours.
Noon.
Time of Mean Pressure, 12.

Min. 297895 at 4 P.M.
Descending Semi-Oscil. "t
lation from 10 A.M. }■ -0166 Time 6 hours,
to 4 KM J

Above Line of Mean 1
Pressure J

•0062 Time 2 hours.

^ p^Lu^"!...?.'!...!!!!.^" } ■">"'' '^''"^ ^ ^°"''-

Evening.

Min. 297895 at 4 P.M.

Max. 29-8099 at 10 P.M.

Mean 29-7999 at 6-30 P.M.
Ascending Semi.Oscilla- 1 ..„. . rT,.^„ ^ , „

tion from 4 to 10 P.M. > "204 Time 6 hours.
Below Line of Mean\ .„,„,™. „, ,

Pressure J 0104Time2i hours.

Above Line of Meani .„,nn'r-™ oiu
Pressure / 0100 Time S^hours.

Night.
Time of Mean Pressure, 1-30 A.M.
Min. 29-7928 at 4 A.M.
Descending Semi-Oscil-
lation, from 10 P.M. 5- -0171 Time 6 hours.

to4 A.M

Above Line of Mean "

icil. I
.M. V

'pTefsurl"!...!..!"!!!!'} •««71 Time2ihours.
^P?rssu^e"!...?L.!!!.!!!} -OlOOTimeSihours.

9. We may distinguish in these results, as delineated in
Plate v., four semi-waves, one between 4 and 10 a.m., a second
between 10 a.m. and 4 p.m., one between 4 p.m. and 10 p.m.,
succeeded by one between 10 p.m. and 4 a.m., being precisely

* By the term tide I mean the course of the barometric wave, from the
period of its ascent to the termination of its descent, that is, from minimum to
minimum.

154 REPORT— 1839.

the critical hours mentioned by M. de Humboldt in his obser-
vations in the torrid zone ; which is not a little remarkable.

These hours are also mentioned by M. Lamanon, engaged
in the voyage of La Perouse,

10. The times of these semi-diurnal variations are therefore
equal, but the variations unequal. The ascent = '0204 in the
evening, exceeding the ascent = "01 33 in the morning by about
'0071 of an inch, or one-third nearly.

A similar result is observable in the descending branches ;
the times are the same, but the fall between 10 a.m. and 4 p.m.
= '0166 is somewhat less than that between 10 p.m. and 4 a.m.
= '0171 by about '0005. These differences are, however,
very small.

On a further examination we find that the two maxima differ
by about '0038 of an inch, that at 10 p.m. being the greatest, and
the minima by about '0033 of an inch. These differences,
however, are likewise inconsiderable, the values being nearly
the same.

If, therefore, we divide the daily march of the pressure into
two complete waves extending through periods of twelve hours
each, we observe the wave at night somewhat exceeds the wave
by day.

11. The principal elements of this horary oscillation are as
follow :

Table VI.

Times of Mean Pressure 7 a.m. 12 noon. 6*30 p.m. 1-30 a.m.

Critical Hours 4 a.m. 10 a.m. 4 p.m. 10 p.m.

Mean Oscillation -01685.

It is not unworthy of remark, that the mean oscillation as
above deduced, corresponds nearly with that arrived at by Mr.
Daniell from his meteorological register near London, the
numbers being '0168 and "0150, a difference not probably
greater than might be expected from the nature of the obser-
vations and difference of latitude.

Horary Oscillation, ^c, in Different Periods of the Year.

12. In Plate VI. will be found delineated the hourly march of
the pressure through a mean day of summer and winter, di-
vided into periods of six months each. The period of summer
being from May to October inclusive — the period of winter from
November to April inclusive. The following Table contains
the oeneral results as deduced from Table II. :

METEOROLOGICAL OBSERVATIONS AT PLYMOUTH. 155

Table VII.

Summer.

Winter.

Mean Pressure

29787

29^811

Time of Mean Pressure

A.M.

P.M.

A.M.

P.M.

h. m.
1 30
4

h. m.

7
10

h. m.
25
4

h. m.
6 30
10

h, m.
2
4

7
10

h. m.
noon.
3

h. m.
6 30
9

Mean Oscillation

•015

•020

Differences from T
Mean of Year J

•0018-

•0031 +

The mean oscillation of winter by this table appears greater
than that of summer, whilst the critical hours of evening fall
an hour sooner.

13. In Plate VII. is dehneated from Table III. the hourly
march of the pressure through a mean day of spring, summer,
autumn and winter, divided into periods of three months each,
and in the following Table are given the principal elements
of these oscillations.

Table VIII.

j Critical Hours.

10 oj

4 «

Mean Oscillation.

•017

•013

•018

•023

Differences from Mean Oscillation of the Year.

•0001+ 1

•0038-

•001 +

■0061-

It appears by this table that the mean oscillation of winter is
the greatest, and that of summer the least ; whilst the mean
oscillation of spring is not very different from that of the whole
year, the oscillation of autumn being a mean between sum-
mer and winter.

156

RKPORT— 1839.

14. Although the times of the horary semi-oscillations in the
different seasons, as shown in Plates V. and VI., are equal, or
nearly so, yet the oscillations themselves are unequal, as in the
former instances for each year delineated in Plate V. ; the as-
cent in the evening generally exceeding the ascent in the morn-
ing, except in the period of the three months of winter laid
down in Plate VII., when the reverse appears to be the case,
a circumstance by no means unworthy of notice.

The difference in the amount of the morning and evening
waves, as shown in Plate VII., is greatest in summer and
spring, and least in autumn and winter.

15. Supposing, as before, the daily march of the pressure to
consist of two complete waves, extending through periods of
twelve hours each, then the comparative amount of these may
be seen in the three following tables :

Table IX.

Showing the Mean Morning and Evening Oscillation in the
Years 1837, 1838, 1839, with their Differences from the Mean
of each year ; together with the Difference of the Morning
and Evening Mean Oscillations.

Years.

Mean Oscill.

Year.

A.M.

P.M.

Difference

Morning and

Evening.

Oscillation.

Difference.

Oscillation.

Difference,

1837

1838
1839

•0180
•0164
•0162

•0150
•0164
•0146

•003-
•001-
•0016-

•0210
•0174
•0179

•003+
•001 +
•0016+

•0060
•0020
•0033

Mean ...

•0168

•015

•0018-

•0187

•0018+

•0038

Table X.
Showing the Mean Morning and Evening Oscillation of Sum-
mer and Winter in Periods of Six Months each, with their
Differences from the Mean Oscillation of each Season, and of
the Year; also the Differences of the Morning and Evening
Mean Oscillations.

Seasons.

1 .

..M.

Diflferences

A.M. & P.M.

Differences.

Season.

Year.

Season.

Year.

Summer .
Winter...

•015
•020

•0125
•0175

•0025-
•0025-

•0043-
•0006

•0175
•0225

•0025+
•0025 +

•0026+
•0056+

•005
•005

METEOROLOGICAL OBSERVATIONS AT PLYMOUTH. 157

Table XL

Showing the Mean Morning and Evening Oscillations of Spring,
Summer, Autumn and Winter, in Periods of three Months
each, with their Differences from the Mean Oscillation of
each Season, &c., of the Year ; also the Difference of the
Morning and Evening Mean Oscillations.

Seasons.

A.M.

P.M.

in
III

Differences.

Season.

Year.

Season.

Year.

Spring ...
Summer .
Autumn .
Winter...

•0170
•0130
•0185
•0230

•0120
•0095
•0175
•0245

•005-
•003-
■001-
•0015+

•0048-
•0073-
•0006+
•0077+

•0220
•0165
•0195
•0215

•005+
•003+
•001 +
•0015-

•005+
•0003-

•0026+
•0047+

•010
•007
•002
•003

16. The differences in the amount of the morning and evening
waves appear to be so regularly developed, that I cannot doubt
of its being included in some general law of the daily pressure.
The fact receives further confirmation from the observations
recorded by Lieut.-Col. Sykes, in his valuable paper on the
Meteorology of Dukhun*, by which it appears that the amount
of the ascent of the barometer, between 4 p.m. and 10 p.m., is
generally greater than that between 4 a.m. and 10 a.m.

I find however by these observations, that the amount of the
wave is increased at night rather by the previous depression
than by the following maximum, since the pressure has been
seldom observed to attain so high a point at night as that from
which it descended in the morning. In our observations, how-
ever, the maximum at 10 p.m. is generally greater, by a small
quantity, than the maximum at 10 a.m., except in the three
months of winter already mentioned. The accuracy of this re-
sult we have no reason to doubt ; for, besides that the obser-
vations have been reduced to 32°, the temperature of the re-
spective times of observation, viz. 10 a.m. and 10 p.m., did not
differ by above '4 of a degree.

17. It may appear, however, worth while to consider how far a
difference of temperature at 4 a.m. and 4 p.m. may, by operat-
ing on the mercurial vapour, cause an undue depression of the
column at the latter hour ; but this source of error is decidedly
negatived by the results given in Table II., Plate II., for the
months of summer, in which we find the amount of depression
at 4-5 A.M. greater than at 4-5 p.m. I am content therefore, at

* Philosophical Transactions for 1835.

158

REPORT — 1839.

present, merely to register the fact, and to collect in the fol-
lowing table a few examples of the diiferences observed in the
semi-diurnal and nocturnal tides at a few places where they
appear to have been most accurately determined, and which I
have derived principally from Lieut.-Col. Sykes's valuable paper
on the Meteorology of Dukhun*.

Table XII.

18. Showing the Differences in the Morning and Evening Tides

at various places, with the Difference from the Mean.

Place.

Morning Tides.

Evening Tides.

Ascending +

Descending —

Ascending -f

Descending —

4-5 to
9-10 A.M.

Differ-
ence.

9.10 A.M.
to 4-5 P.M.

Differ-
ence.

4-5 to
9-10-11 P.M.

Differ,
ence.

10-11 P.M.
to 4-5 A.M.

Differ-
ence.

Madras ...
London...
Poona. ...
Plymouth

•0560
•0227
•0656
•0168

•0470
•0185
•0445
•0133

•009 -
•004 +
•021 -
•0035-

•0790
•0289
•1116
•0166

•023 +
•006 +
•046 +
•0002-

•0630
•0272
•0884
•0204

•007 +
•004 +
•022 +
•0036+

•0350
•0162
•0181
•0171

•021 -
'•006 -
•047 -
•0003+

Ascending +

Descending -

r Madras T
Difference of a.m. and p.m. J p°"^°" ■
Plymouth

•016
•008
•044
•007

•0440
•0127
•0935
•0005

We may perceive by this table that the differences in the
morning and evening semi-oscillations may be very consider-
able. At Poona, for example, the afternoon ascending tide
was nearly twice as great as the morning ascending tide ; in
order therefore to fix with precision the amount of the baro-
metric oscillation in different places, we require in the present
state of our knowledge of this question, at least an observation
at each of the critical hours, since the mean result in column
2. may differ considerably from the others, especially in a
limited series of observations.

19. For perfect experimental deductions, nothing short of a
long series of continued hourly observations will in the present
state of this question suffice, since we are quite unacquainted
with the fluctuations which may possibly occur at different
periods and seasons, and in different states of the pressure ;
all the observations therefore hitherto made, although ex-
tremely valuable, must still be considered in this sense compa-
ratively deficient.

* Transactions of the Royal Society for 1835. Part I.

METEOROLOGICAL OBSERVATIONS AT PLYMOUTH. 159

20, Thus the results given in Table XII. cannot be regarded
as strictly comparable, the observations having been in some in-
stances confined to short periods of time, also to different sea-
sons, and to certain portions of the day, in which the difference
from the mean oscillation of the twenty-four hours has never
yet been ascertained. In order to make such observations
completely available, it is requisite to determine these differ-
ences in different places, and at different altitudes above the
sea, not only for a mean year, but for different seasons, and
even months. We have not, however, at present, data com-
petent to such deductions.

21. I have arranged in the three following tables such inform-
ation on this point as is derivable from the extensive series of
hourly observations now under consideration, and which will
be found to contain the amount of the four semi-oscillations in
different years and seasons, with their various differences from
the mean of each.

Table XIII.

Showing the four Semi-Oscillations of the Years 1837, 1838,
1839, with the Difference of each from the Mean Oscillation
of the Year, together with the Differences of the Two
Ascending and the Two Descending Oscillations.

Years.

Morning Tides.

Evening Tides.

Ascending +

Descending —

Ascending +

Descending —

1 to 10 A.M.

Differ-
ence.

10 A.M.
to 4 P.M.

Differ,
ence.

4 to 10 P.M.

Differ-
ence.

10 P.M.

to 4 A.M.

Differ-
ence.

1837
1838
1839

•01800
•01G40
•01625j

•0126
•0138
•0137

•0054-
•0026-
•0025-

•0174
•0170
•0155

•0006 -
•0006 +
•0007 -

•0234
•0190
•0188

•0054+
•0026+
•0025+

•0186
•0158
•0170

•0006 +
•0006 -
•0007 +

Mean

•01688^ -01336

•00352-

•01663

•00025-

•0204

•00352 ^01713

•00025+

Years.

Ascending +

Descending —

Differences of a.m. and p.m.

r 18371
\ 1838 [
1 1839 J

•0108
•0052
•0051

•0012
•0012
•0015

Mean

•007

•0005

160

RKPORT— 1839.

Table XIV.

Showing the four Semi- Oscillations in Summer and Winter in
periods of Six Months each, with the Differences of each from
the Mean of the Whole Year, together with the Differences of
the two Ascending and the two Descending Oscillations.

Seasons.

Morning Tide.

Evening Tide. 1

Ascending.

Descending.

Ascending.

Descending. 1

4tolOA.M.

Differ-
ence.

10 A.M. to 4 P.M.

Differ-
ence.

4 P.M. to 10 P.M.

Differ-
ence.

10 P.M. to 4 A.M.

Differ
ence.

Summer .

•015

•Oil

•006-

•014

•003-

•019

•002+

•016

•0008

Winter. .

•020

4 to 10 A.M.
•015

•002-

lOA.M.toSP.M.
•020

•003 -i-

3 P.M. to 9 P.M.
•025

•008

9 P.M. to 4 A.M.
•020

•003

Seasons.

Ascending -f

Descending -

DifFerence of a.m. and p.m.

J Summer "1
\ Winter J

•008
•010

•002
•000

Table XV.

Showing the four Semi-Oscillations of Spring, Summer, Autumn
and Winter, in Periods of Three Months each, with the
DifFerence of each from the Mean of the Whole Year, toge-
ther with the Differences of the two Ascending and the two
Descending Oscillations.

Seasons.

Morning Tides.

Evening Tides. 1

Ascending
+

Differ-
ence.

Descending -

Differ,
ence.

Ascending +

Differ,
ence.

Descending —

enc

Spring .

•017

4 to 10 A.M.

•012

•005-

lOA.M. to 4 P.M.
•012

•005-

4 to 10 P.M.
•022

•005+

10 P.M. to 4 A.M.
•022

•005

Summer

•013

5tolOA.M,
•010

•007-

10 A.M. to 5 P.M.
•009

•008-

5 to 10 P.M.
•016

•008-

10 P.M. to 5 A.M.

•017

•000

Autumn

•0185

4 to 9 A.M.

•015

•002-

9 A.M. to 4 P.M.
•020

•003 +

4 P.M. to 9 P.M.
•022

•005 +

9 P.M. to 4 A.M.

•017

•000-

Winter .

•023

StolOA.M

•019

•002-f

10 A.M. to 3 P.M.

•030

•013 +

3 to 11 P.M.
•027

•010+

11 P.M. to 5 A.M.

•016

■ ■ ■■ -J

•000

Seasons.

Ascending +

Descending-

DifFerence of a.m. and p.m.

r Spring "1
1 Summer 1
1 Autumn [
[Winter

•010
•006
•007
•008

•010
•008
•003
•014

METEOROLOGICAL OBSERVATIONS AT PLYMOUTH. 161

The results in the three last tables point out, 1st, That the
descending semi-oscillations from 10 a.m. to 4 p.m., and from
10 P.M. to 4 A.M., approach nearest the mean oscillation of the
periods to which they belong.

Thus in Table XIII. the descending oscillations at these
hours differ but little from the mean oscillation of the respect-
ive years : — the same is true in Tables XIV. and XV. The
descending tides differ but little from the mean of their re-
spective seasons; — these differences, however, are not expressed
in the tables.

2nd. It may be perceived that the mean of the two ascending
or two descending oscillations is exactly the mean oscillation
of the periods to which they belong.

Hence the differences from the mean are equal, and in
opposite directions ; thus in tlie semi-oscillations for summer
(Table XIV.), the morning descending oscillation = '014 is as
much below the mean oscillation '015, as the evening descend-
ing oscillation = '016 is above it.

3rd. That the ascending tide from 5 to 10 p.m. of summer
(Table XV.), approaches very nearly the mean of the year.

4th. That the descending tides, from 9-10 p.m. to 4 a.m. of
summer (Table XIV.), and of summer, autumn and winter
(Table XV.), approach also very nearly to the mean oscillation
of the year. Hence, if only one set of observations can be
made, and those in the day time, it would be desirable to
register them during the three months of summer at 4 p.m.
and 10 P.M. If two sets of observations at the critical hours
can be made, then it would appear desirable to choose either
of the periods of the two ascending or the two descending
tides, and take the mean of the two, as the mean of the period.
If these be continued for a whole year, we thence obtain the
mean oscillation of the year ; — if for any season, the mean os-
cillation of that season : — whence, knowing the difference from
the mean oscillationof the whole year, we may apply the requisite
correction.

So far as these observations extend therefore, we may infer,
that four observations in the day in the three months of spring,
viz. at 4 and 10 a.m., and 4 and 10 p.m. ; or, otherwise, at 10
A.M. and 4 p.m., at 10 p.m. and 4 a.m., would give a mean result,
differing from the mean oscillation by a very small quantity.

There is little doubt, as suggested by Major Sabine, in his
Register of the Barometer at Port Royal*, Jamaica, that the
amount of the horary oscillation varies with some function of

* Daniell's Meteorology.
1839. M

162

REPORT — 1839.

the distance from the equator ; and Professor Forbes, in his
excellent paper on the Horary Oscillations of the Barometer
near Edinburgh, has given a formula which apphes with con-
siderable accuracy to such observations as have been yet made;
and although, as we have seen, considerable variations from the
mean may arise from the times and seasons of such observa-
tions, nevertheless the author has evinced admirable philoso-
phical tact in his method of treating the subject, and has for-
tunately selected for his term of comparison the semi-mean
oscillation between 10 and 4 p.m., which perhaps, upon the
whole, may be found to give a tolerably fair approximation.
The question, however, must still be considered in its infancy,
and but little investigated by the powerful aid of contemporary
and long continued hourly observations in different latitudes.
It would therefore, at present, be useless to enter upon a dis-
cussion of the anomalies alluded to by Professor Forbes in the
observations hitherto made at different places. Thus, at Paris
the minimum oscillation was observed to take place in summer,
whilst, by Professor Forbes's deductions, it occurred in winter.
The results now under discussion give the minimum also in
summer, but the maximum in winter. We require, therefore,
a very accurate series of observations continued hourly for a
long time, in order to reconcile such discrepancies, and bring
us fairly acquainted with the course and nature of these atmo-
spheric tides.

It may not be uninteresting, in concluding for the present
this part of the discussion, to tabulate a few of the best
authenticated observations of the barometric oscillations in
different parts of Great Britain.

Table XVI.

Place.

Altitude

above Sea

in feet.

Lat.

Horary Oscillations

Mean Oscillation

Morning —

Evening +

Night -

as deduced from
the Two - Oscil-
lations.

10 A.M.
to 4 P.M.

4 P.M.
to 9, 10 ,11P.M.

9, 10, 11 P.M.
to 4 A.M.

Plymouth
London ...

York

Edinburgh

430

50-21
50-51
53-56
55-55

-0166
•0280
-0174
•0106

•0204
•0230
•0170
•0097

•0171
•0166
•0094

•0168
•0220
•0134

The mean oscillation deduced from London in the above table
will, I apprehend, upon the whole, be found too great, owing
possibly to the want of a sufficient number of observations,
especially at 4 and 10 a.m. If we substitute for it Professor

METEOROLOGICAL OBSERVATIONS AT PLYMOUTH.

163

Daniell's result, '015, and take the morning negative oscilla-
tion for Edinburgh = '0106 as a near approximation to the
mean, then we have the following series : —

Table XVII.

Latitude,

50.21

50.51

53.56

55.55

Oscillation

•0168

•0150

•0134

•0106

By which we perceive that the amount of the oscillation is less
in the greater latitudes.

Professor Forbes's formula "11 93 cos^ 5 — '0150, &c., cannot
exactly correspond with these numbers, except the last, since
his index of the cos . $ w^as obtained by selecting observed
oscillations between 10 and 4 a.m. According to this formula
we should have for the oscillations at these latitudes,

Plymouth. London. York. Edinburgh.

'0238; -0^27; '0167; -0130.

Now the formula gives a fair approximation to the evening
oscillations at these places, which are —

Plymouth. London. York. Edinburgh.

•0204; -0230; '0170; '0097.

It may be further remarked as a curious coincidence, that
the night oscillation at London corresponds with the morning
oscillation at Plymouth, whilst the morning oscillation at York
corresponds nearly with the night oscillation at Plymouth.

Average Monthly Pressure,

In Table IV. we have given the average monthly pressure
for the years 1837, 1838, 1839, together with the mean of these
years, by which it will be perceived that the annual variations
have not for this period of time been at all regular.

Thus in the year 1837 the maximum occurred in October,
and the minimum in September, the mean about July, whilst in
1838 the maximum occurred in July, the minimum in Novem-
ber, and the mean in January ; in 1839 the maximum occurred
in April, the minimum in September, and the mean about
June.

The table, however, upon the whole, indicates a maximum
and minimum towards the close of the year, and a mean in
spring, which perhaps will become more apparent by an in-
creased number of observations.

In the following table will be found the deviations from the
mean of the three years through the different months, in which

M 2

164

REPORT 1839.

it will be seen that the greatest deviations occurred in October
and November, and the least in March.

Table XVIII.
Showing the Deviations of the Mean Monthly Pressure for the
Mean for the Years 1837, 1838, 1839, reduced to 32° of
Fahrenheit.

Jan.

Feb.

March.

April.

May.

June.

July.

August.

Sept.

Oct.

Nov.

Dec.

+•062

-•055

f^OOl

+•035

+•034

-•012

+•040

+•057

-•094

+•129

-•203

-•002

The months of March and December, therefore, approach
nearest the mean, whilst the maximum and minimum occur in
October and November.

The recurrence of the mean pressure four times in the
twenty-four hours at once points out the hours, or pairs of
hours, which would be most likely to give the mean pressure of
the twenty-four, since it would occur either at the stated hours
themselves, or between those falhng on different sides of them.

In the following table will be found the deviation of each
hour from the mean, and in the next table the pairs of hours,
the mean pressure of which approach nearest the mean of the
whole twenty-four.

Table XIX.

Showing the Deviation of each Hour from the line of Mean

Pressure.

A.M.

P.M.

Hours.

Deviation.

Hours.

Deviation.

•0018 +

•0042 -

*-0006 -

•0077 -

•0055 -

•0091 -

•0071 -

•0104-

•0071 -

•0061 -

•0039 -

•0029 -

*^0003 +

*^0020 +

•0032 +

•0062 +

•0049 +

•0095 +

•0062 +

•0100 +

•0046 +

•0093 +

*-0003 +

•0066 +

By this table it appears, 1st, that the single hours, which
give the nearest approximation to the mean, are 7 a.m. and 12
at noon, next to these 2 a.m. and 7 p.m. ; 2nd, that the mean

METEOROLOGICAL OBSERVATIONS AT PLYMOUTH.

165

annual pressure of any hour does not differ more than about
•01 from the mean annual pressure of the twenty-four hours.

We may lience render any past register at Plymouth avail-
able in deducing the mean pressure, by applying, according to
the signs, the corrections given in the preceding table.

Table XX.

Showing the Pairs of Hours, the Mean Pressure of which ap-
proaches nearest the Mean of the Twenty-four Hours.

Pairs of
Hours.

8 A.M.

and
6 P.M.

3 A.M.

and
8 P.M.

9 A.M.

and
1 P.M.

3 P.M.
and

10 A.M.

4 A.M.

and
10 A.M.

9 A.M.

and
5 P.M.

2 P.M.

and
8 P.M.

11 A.M.

and
6 P.M.

2 P.M.

and
9 P.M.

6 A.M.
and

7 P.M.

Deviations

•0001 +

•0003+

•0004+

•0005-

•0006-

•0007-

•0008+

•0009+

•0010-

The mean pressure therefore at Plymouth may be obtained
by observations at either of the pairs of hours above given.

It may be further seen by Table I. that the mean maximum
and mean minimum pressures are 29*8080, and 29*7911, giving
a mean oscillation = *0169, or very nearly the same as that
= '01688 already deduced from the four same oscillations,
Table VI.

It is not therefore unimportant to determine the hours which
either give exactly or come nearest the mean maxima and mi-
nima of the twenty-four.

Now the pressure at 3 p.m. differs extremely little from the
mean minimum, the difference being only -0003, whilst the
mean pressure at 11 p.m. approaches nearest the mean maxi-
mum, the difference being only '0012. If we had taken these
observations at these hours as the mean maxima and minima of
the twenty-four, we should have had for the mean oscillation
•0184, which would have differed from the true mean oscilla-
tion by -0015, and for the mean pressure 29*8000, which would
have been very near the true mean pressure.

The mean results given in Table I. enable us to find the
single hours, or pairs of hours, which give either singly or
combined the mean maxima and minima pressures, or approach
nearest to them. These are given in the next table.

166

REPORT 1839.

Table XXI.

Showing the Hours which, either singly or combined, approach
the Mean Maxima and Minima Pressures.

Mean Maximum
Pressure. <

29-8080.

Hour.

Single Hours.

Double Hours.

8 P.M.

9 P.M.

11 P.M.

10 A.M.

and
10 P.M.

8 P.M.

and
10 P.M.

11 P.M.
and

12 P.M.

11 P.M.

and
8 P.M.

Deviations

•0019-

•0014+

•0012+

•000

•0002

•0004

Mean Minimum
Pressure. <
29-7911.

Hour.

3 P.M.

2 P.M.

4 P.M.

4 A.M.

5 P.M.

3 A.M.

4 A.M.

and
4 P.M.

Deviations

•0003-

•0011+

•0016-

•0017+

•0027+

•0033+

•000-

We may infer from this table that three observations at
3 P.M., and again at 8 and 10 p.m., would give us the mean minima
and mean maxima pressures very nearly ; consequently the mean
pressure and the mean oscillation = -0172, which differs from
the true mean oscillation by only '0003 + . The remaining
hours may afford approximation by applying corrections ac-
cording to the signs.

I regret that it is not in my power to give the results of any
good discussion of the force of the wind for each hour without
regard to direction, as I have reason to believe it would throw
some light on the phaenomena of the horary oscillation. Thus
I have little doubt that the suppression of the morning oscil-
lation observed in the months of summer and spring in Plate 3
is coincident with the force of the wind, which, from a cursory
examination of the indications of Osier's anemometer, appears
to be in those seasons greatest at those periods. I hope in a
future Report to be enabled to put the Association in possess-
ion of some further information on this point.

The mean hourly observations of pressure are included in
Plate 4, with those on temperature, and the dew point, as
determined from the indications of the moistened thermometer
by Professor Apjohn's formula. The following table contains
the Mean Results of the latter for the Years 1837, 18^38, 1839.

METEOROLOGICAL OBSERVATIONS AT PLYMOUTH. 167

Table XXII.

■3

Hour.

1a.m.

47-52

46-20

1-32

4500

47-33

46-03

1-30

44-75

47-11

45-92

1-19

44-75

47-00

45-66

1-34

44-25

46-98

45-77

1-21

44-75

47-41

46-01

1-40

44-50

48-44

46-83

1-61

45-25

49-68

47-51

2-17

4500

51-30

48-50

2-80

35-26

52-84

49-45

3-39

46-25

53-00

5002

3-88

46-75

54-51

50-40

4-14

46-75

1 A.M.

45-83

50-55

4-28

46-75

54-77

50-44

4-33

46-75

54-25

50-24

401

46-75

53-45

49-80

3-65

46-75

52-27

49-06

3-21

46-25

51-24

48-46

2-78

46-00

50-28

47-90

2-38

45-75

49-44

47-51

1-93

45-75

48-83

47-17

1-66

45-60

48-48

46-93

1-55

45-60

48-10

46-66

1-44

45 00

47-80

46-43

1-37

45-00

Mean

50-32

47-89

2-43

45-60

It appears by these results,

1st. That the greatest dew point does not exceed 47 degrees
or the point of minimum temperature.

2nd. That the least dew point does not fall below 44 degrees,
and occurs about the time of minimum temperature, viz. at 4, 5,
6, A.M.

3rd. That the mean dew point = 45*6 diiFers from the
mean temperature = 50*3 by about 5 degrees, which may
therefore be taken as the mean dryness on the thermometric
scale.

4th. That the mean dew point occurs twice in the twenty-
four hours, viz., about 9 a.m. and 9 p.m., the interval being
nearly twelve hours.

5th. The mean temperature of the dew point approaches very
nearly the mean minimum temperature of the wet bulb ther-
mometer.

These results are, so far as I know, the first which have been

168 REPORT — 1839.

derived from Dr. Apjohn's formula, applied to an extensive se-
lies of hourly observations.

When we consider of how great importance it is to Meteoro-
logy to perfect the method of hygrometric observations by the
moistened thermometer, I cannot but hope that those approxi-
mations may lead to future and more accurate results. Having
found the formula in very many instances give close approxima-
tions to the dew point, as determined by the direct method of
Daniell, I cannot but think that it will eventually become an
important acquisition to this department of science.

The very recent completion of the numerical results of these
first years' hourly observations on the barometer and dew point
necessarily limits this Report to some of the more immediate de-
ductions which they present. It is further to be observed that
the weather of these years has been of a disturbed and unset-
tled character ; especially the last two, which have abounded
in heavy rain and hard gales. Comparing the easterly and
westerly winds (leaving the due north and south out of the ac-
count), I find that the west winds have blown for one-half the
whole period, and the easterly for one-quarter only. The ratio
being nearly 2:1. Comparing the northerly with the south-
erly winds (leaving the due east and west out of the account),
the latter have blown for one-fourth of these three years, and
the former for one-eighth ; the ratio being also about 2:\. The
great prevalence of the southerly and westerly over the north-
erly and easterly winds has been accompanied by a mean press-
ure probably below what will appear in the mean of a greater
number of years. In these years there occurred twenty-eight
hard gales, principally from S.E. to N.W.

Horary Observations on Temperature.

Since the discussion of the observations on temperature, two
valuable communications have been placed in my hands ; the
first by Professor Bache, which contains an hourly register of
the thermometer from June 1837 to June 1838, at Frankford
Arsenal, by Captain Alfred Mordecai, of the United Service
Corps of Ordnance. The second contains three hourly regis-
ters for the year 1837, by Major Ord, of the Royal Engineers,
at the three most important meteorological and geographical
stations in the island of Ceylon, viz., Colombo, Kandy, and
Trincomalee.

I am enabled from these registers to extend the table given
in page 199 of the Fifth Report of the Association, so as to in-
clude these places.

METEOROLOGICAL OBSKRVATIONS AT PLYMOUTH.

169

Table XXIII.

Shewing the Times of Morning and Evening Mean Temperature
in different Latitudes, and at various Heights above the Sea.

Name of Place.

'A
I
2

Longitude.

•s
X

P
5

Ill

ifi

rA.

lii

Leith

Plvinouth

55-56

50-21

45-36

39-57

6-57

7-18

8-33

3-13 w.

4- 6w.
11-55 E.
75- 9w.

80- E.
80-49 E.
81-24 E.

Feet.
25
75

1682
60

600
400

near

48
52

49-28
8016
74- 5

81-

9-13

8-41

8-10

10-35

10-

10-35

8-27

7-52

7-30

9-30

8-40

1114

11-

11-14
11-20
10-55
11-
11- 5

Padua

Philadelphia

Kandy

Trincomalee

This table is of much value, since it contains the results of a
series of observations on temperature, calculated to establish
the two daily periods, the mean temperature of which equals
the mean temperature of the twenty-four hours.

It may be seen by this table that notwithstanding some va-
riations occur in the times, yet, as observed by Professor Forbes
in his excellent Report on Meteorology, the interval between the
morning and evening mean is upon the whole remarkably con-
stant, especially when we consider the difficulty of obtaining
hourly observations for a great length of time, so as to com-
pletely neutralize every casual disturbance.

Major Ord was led to adopt a two-hourly register in prefer-
ence to an hourly register, from a conviction that an equal if
not a greater degree of accuracy would be obtained in that par-
ticular climate.

The register was carried on by the intelligent Scots of the
98th Native Highlanders, and non-commissioned officers of the
Royal Artillery.

Thus the fine efforts of an hourly register, first commenced
and discussed under the direction of Sir D.Brewster atLeith, in
the years 1824 and 1825, have been, and will doubtless still con-
tinue to be, followed by similar registers, the results of which
cannot fail to be of the highest value to Meteorology, as being
the only channel through which any specific practical informa-
tion can be obtained in this most valuable department of
physics.

Whatever therefore may be the claims of further inquirers
on the consideration of the scientific world, it must never be
forgotten that Sir David Brewster was the first to obtain an

170 REPORT — 1839.

hourly meteorological register for a series of years, and to en-
rich this branch of science with many important facts which
such a register under the powerful scrutiny of his philosophical
mind would necessarily supply*.
Plymouth, August 10, 1839.

* The remaining observations of the year 1839 have been combined with the
others and discussed since this Report was presented to the Physical Section of
the Association at its last Meeting at Birmingham.

REPORT— 1839. 171

On the action of Air and Water upon Iron, 8fc.

Mr. Mallett reported the progress of the investigation on
his subject, which was entrusted to Professor E. Davy and
himself, and stated his expectation, that a full Report of the
Results of the experiments would be presented to the next
Meeting of the Association. (See Report for 1838.)

Report on a Machine for the detection and measurement of
Gases present in small quantities in Atmospheric Air, Coal-
Gas, Sfc, By William West.

This instrument consists of a gasmeter turned slowly round by
clockwork, so as to draw the air, or other mixture of gases
under examination, through liquids proper to combine with and
detain the gases sought, as solution of lime or barytes for car-
bonic acid, a dilute acid for ammonia, a salt of lead for hydro-
sulphuric acid, &c. The hands on the clock-face denote the
volume of air thus submitted to partial analysis, and from the
weight of the new compound formed in the liquids the propor-
tion of foreign gases separated may be obtained by calculation.

The advantage of this apparatus over the former modes of
attempting the same object, consists in the large quantity which
can thus be examined, several hundred cubic feet for instance,
instead of a few inches. It is intended to apply the apparatus
to the examination of the air of towns, by simultaneous experi-
ments with machines in the town and the adjacent country,
some of these to be at different distances and variously placed
as to the direction of the wind. These experiments will require
longer time and additional apparatus. The principle has been
successfully applied to measure the proportions of sulphuretted
hydrogen, and of ammonia in coal-gas.

On the subject of a resolution adopted by the Meeting of the
British Association held at Newcastle, in August 1838, to the
following effect : —

"Resolved, — ^That it is desirable that the whole of the stars
observed by Lacaille at the Cape of Good Hope, the observa-
tions of which are recorded in his Ccelum Australe Stelliferum,
should be reduced.

" That Sir J. Herschel, Mr. Airy, and Mr. Henderson, be a
Committee for carrying the same into effect, and that 200/. be
appropriated for the purpose."

172 REPORT 1839.

The Committee report, — That considerable progress has been
made in the reduction of the stars in Lacaille's Coeliim Australe
Stelliferum ; and that although only a small portion of the mo-
ney appropriated has been actually expended, nearly the whole
will probably be required during the ensuing year to complete
the work.

On the subject of a resolution agreed to by the British Asso-
ciation at their Meeting at Newcastle, in August 1838, to the
following effect: —

'' Resolv^ed, — That it is desirable that a revision of the nomen-
clature of the stars should be made, with a view to ascertain
whether or not a more correct distribution of them amongst the
present constellations, or such other constellations as it may be
considered desirable to adopt, may be formed.

" That Sir J. Herschel, Prof. Whewell, and Mr. Baily, be a
Committee for that purpose, and do report on the same at the
next Meeting of the Association.

" That the sum of 50/. be appropriated to defray any expenses
that may be incurred in this inquiry. ''

Your Committee report, — That some progress has been made
in reforming the nomenclature of the northern constellations,
and that they have commenced laying down the stars in the
southern on a planisphere, according to their observed actual
magnitudes, for the purpose of grouping them in a more conve-
nient and advantageous manner. No expense has yet been in-
curred in this inquiry ; but the Committee are desirous that the
grant should be continued for another year.

On the subject of a resolution adopted by the Meeting of the
British Association held at Newcastle, in August 1838, to the
following effect : —

" Resolved, — that Sir J. Herschel and Mr. Baily be requested
to make application to Government for increase in the instru-
mental power of the Royal Observatory at the Cape of Good
Hope, and the addition of at least one assistant to that esta-
blishment."

The Committee report, — That application had already been
made to Government previous to the date of this resolution,
viz. on the 29th June, 1838, and on other occasions, to the ef-
fect therein mentioned ; and that in consequence of those ap-
plications, aided no doubt by a knowledge of its being the wish
of the British Association, (such wish having been communi-
cated to Lord Minto by Sir J. Herschel in a letter dated Nov.
5, 1838,) they have great pleasure in being able to state, —

1st. That — Mann, Esq., has been appointed as an addi-

RKPORT— 1839. 173

tional assistant to the Cape Observatory at a liberal and suffici-
ent salary, and is already on his voyage thither to take on him-
self the duties of his office.

2nd. That Jones's mural circle, hitherto used at Greenwich,
has been despatched by the orders of the Lords Commissioners
of the Admiralty to supply the place of the defective one in use
up to that time at the Cape, and is already probably arrived
there, — an improvement of essential importance, the Greenwich
instrument having been shown, by many years' trial in the hands
of Messrs. Pond and Airy, to be of the highest excellence. The
liberality of Mr. Airy in resigning this noble instrument to his
brother astronomer cannot, in your Committee's opinion, be too
highly estimated.

3rd. That for the purpose of enabling Mr. Maclear, the di-
rector of the Cape Observatory, to prosecute with effect the re-
measurement of Lacaille's arc of the meridian at the Cape, the
Lords Commissioners of the Admiralty have procured from the
Board of Ordnance the use of Colonel Colby's excellent com-
pensation-measuring bars, the same which have been employed
by him in the measurement of the Irish base, which are now
actually on their voyage to perform a similar office at the Cape.

4th. That the Lords Commissioners of the Admiralty have, in
pursuance of the same object, applied for and obtained the use
of an excellent theodolite, the property of the Royal Astrono-
mical Society, and by them liberally granted for the purpose of
remeasuring Lacaille's triangles.

On the subject of a resolution adopted by the Meeting of the
British Association at Newcastle, in August 1838, to the fol-
lowing effect : —

*' That Sir J. Herschel be requested to superintend the Re-
duction of Meteorological Observations made, agreeably to his
recommendation, at the Equinoxes and Solstices, and that 100/.
be placed at his disposal for that purpose."

Sir J. Herschel reports, — That he has, within the course of
the year elapsed since the last Meeting of the Association, re-
ceived several series of observations from distant stations, com-
pleting wholly or in part the series before transmitted from
those stations ; but that several are still deficient, which, how-
ever, must now be considered either as irrecoverably lost, or as
never having been made. That, partly owing to the compara-
tive inutility of reducing incomplete series, and partly to the
pressure of other business, especially to that arising from the
Magnetic Expedition and observatories, which will form the sub-
ject of a distinct report, he has been prevented hitherto from

174 REPORT — 1839.

making material progress in preparing the observations in ques^
tion for reduction, but hopes before the next Meeting to get
them executed ; and requests the grant of the Association may-
be continued for that purpose, and that the surplus, if any, may
be made applicable to the reduction of other meteorological ob-
servations communicated to him while resident at the Cape and
since, and not made at the solstices and equinoxes, but in the
form of monthly registers.

On a grant of 500/. made for the reducti(m of stars in the
Histoire Celeste, under the superintendence of Mr. Baily, Mr.
Airy, and Dr. Robinson,

Mr. Baily reports, — That the reduction of stars in the Histoire
Celeste has been commenced, and already about 13,000 stars
have been reduced at an expense of about 170/. It is presumed
that the greater part (if not the whole) of the remainder may be
completed in the course of the ensuing year, and it is therefore
expedient that the grant of money should be continued.

On a grant of 500/. made for the purpose of extending the
catalogue of the stars of the Royal Astronomical Society, under
the direction of Mr. Baily, Mr. Airy, and Dr. Robinson,

Mr. Baily reports, — That with respect to the extension of the
Astronomical Society's catalogue of stars, about one half of the
computations are completed in consequence of the liberal grant
from the British Association at Liverpool, and about 180/. of
that grant has been expended ; the whole of the remainder of
the grant will probably be required before the next Meeting of
the Association.

The Committee appointed at Newcastle (in Report for 1838,
p. xxiii.) for the purpose of applying to Government for a pro-
per place for the deposit of records connected with the mining
transactions of Great Britain, reported that a room adjoining
the Museum of Economic Geology had been appointed for
their reception, which would be placed under the custody of
a proper keeper.

The Committee appointed at Newcastle (in Report for
1838, p. xxv.), superintending Inquiries into the Statistics of
the Collieries of the Tyne and Wear, presented a notice of the
progress of their researches.

NOTICES

AND

ABSTRACTS OF COMMUNICATIONS

TO THE

BRITISH ASSOCIATION

FOR THE

ADVANCEMENT OF SCIENCE,

AT THE

BIRMINGHAM MEETING, AUGUST, 1839.

ADVERTISEMENT.

The Editors of the following Notices consider themselves respon-
sible only for the fidelity with which the views of the Authors are
abstracted.

CONTENTS.

NOTICES AND ABSTRACTS OF MISCELLANEOUS
COMMUNICATIONS TO THE SECTIONS.

MATHEMATICS AND PHYSICS.

Page

Professor Powell on a new case of Interference of Light 1

Professor Powell on the Explanation of some Optical Phsenomena ob-
served by Sir David Brewster 1

Professor Powell on certain Points in the Wave-theory as connected
with Elliptic Polarization, &c 2

Mr. Fox Talbot's Remarks on M. Daguerre's Photogenic Process . . 3

Professor Daubeny on an Apparatus for obtaining a numerical estimate
of the Intensity of Solar Light, at different periods of the day, and in
different parts of the globe 6

Professor Forbes's Notice respecting the Use of Mica in polarizing Light. 6

Mr. James Nasmyth on the bending of silvered Plate Glass into Mirrors 7

Dr. Andrew Ure on Photometry, or a mode of measuring diffuse day-
light comparatively, at any time and place 7

Mr. J. F. GoDDARD on the use of the Oxy-Hydrogen Microscope in ex-
hibiting the phsenomena of Polarization 8

Sir J. F. W. Herschel's Letter to the Rev. William Whewell, President
of the Section, on the Chemical action of the Solar Rays ..... 9

Rev. Professor Lloyd on the best Positions of three Magnets, in refer-
ence to their mutual action 12

Mr. Addison's Meteorological Observations made at Great Malvern du-
ring the years 1835, 1836, 1837, and 1838 14

Col. Sykes on certain Meteorological Phsenomena in the Ghats of Western
India 15

Mr. FoLLETT Osler's Account of some Indications of the Anemometers
erected at Plymouth and Birmingham 17

Mr. Eaton Hodgkinson on the Temperature of the Earth in the deep
Mines of Lancashire and Cheshire 19

Professor Andrew Ure on a New Calorimeter, by which the heat dis-
engaged in combustionmay be exactly measured, with some introductoiy
Remarks upon the Nature of different Coals 20

Professor Stevelly on a method of filling a Barometer without the aid
of an Air-pump, and of obtaining an invariable level of the surface of
the Mercury in the Cistern 21

IV CONTENTS.

Page
Dr. Ure's Experiments to determine the Fluency or Viscidity of different
Liquids at the same Temperature, and of the same Liquids at different

Temperatures 22

Mr. W. J. Frodsham's Notice of a comparative Pendulum .... 24
Mr. J. K. Smythies on the Motion of Points or Atoms subject to any

law of force 24

Rev. William Hopkins on certain Results, regarding the minimum
thickness of the Crust of the Globe, which might be consistent with
the observed phsenomena of Precession and Nutation, assuming the

earth to have been originally fluid 26

Rev. Charles Blackburn's Notice of certain Analytic Theorems . . 26
The Rev. Wm. Whe well's Remarks on Dr. Wollaston's argument re-
specting the infinite Divisibility of Matter, drawn from the finite Ex-
tent of the Atmosphere 26

Mr. E. J. Dent's Account of a recent successful Experiment to deter-
mine, by means of Chronometers, the difference of Longitude between

Greenwich and New York 27

Mr. E, J. Dent's Note accompanying a Table of the Rate of the Transit-
Clock in the Radclyff Observatory, Oxford 28

Mr. Parsey on Natural Perspective 29

Lieut. Morrison on an analogy between the atomic weights of certain
Gases and the expansions of the primitive colours of the Solar Spectrum 29

CHEMISTRY.

Professor Graham on the Theory of the Voltaic Circle 29

Professor Schonbein's Notice of new Electro-chemical Researches . . 31
Professor Reich's Researches on the Electrical Currents on Metalliferous

Veins made in the mine Himmelsfurst, near Freyberg 34

Dr. Hare's Observations on the preparations of Barium and Strontium 36
Rev. W. R. Grove on a small Voltaic Battery of extraordinary energy . 36
Mr. Thomas Spencer's Notices of Experiments on the deposition of

Metals by Voltaic Action 38

Dr. Samuel Brown on the Artificial Crystallization of certain Metallic

Carburets, as extensive of the Theory of Crystallization 39

Dr. George Wilson's Experimental Demonstration of the certain ex-
istence of Haloid Salts in Solution 41

Dr. Thomas Clark on the limits within which the Atomic Weights of

Elementary Bodies have been ascertained 43

Dr. Charles Schaphaeutl on the relative Combinations of the Consti-
tuents of Cast Iron, Steel, and Malleable Iron 49

CONTENTS.

Page

Mr. T. Richardson on the Composition of Idocrase 52

Dr. Charles Upham Shepard's Observations on Meteoric Iron found

in different parts of the United States of America 54

Mr. R. Phillips on the Synthetical Composition of White Prussiate of

Potash 56

Dr. G. O. Rees on the existence of Fluoric Acid as a constituent of certain

Animal Substances 5"

Professor Hess's Description of an Apparatus for the Analysis of Or-
ganic Substances 57

Dr. R. D. Thomson on the Proofs of the existence of free Muriatic Acid

in the Stomach during Digestion 58

Rev. T. ExLEY on the Elementary Constitution of Organic Substances . 58

Dr. Ure's Experiments on Fermentation, with some general remarks • 59

Mr. Benson on the theory of the formation of White Lead 60

Dr. Mackay on Matias Bark 61

Mr. Charles Thornton Coathupe on an improved method of gradu-
ating Glass Tubes for Eudiometrical purposes 62

Mr. Charles Thornton Coathupe's Notice of an Apparatus for deter-
mining the quantity of Carbonic Acid Gas in deteriorated atmospheres 63

Baron Eugene de Menil on a New Safety Lamp 64

Dr. D. B. Reid's Notice of a Chemical Abacus 65

Count du Valmerino's Remarks on Gas-Lighting 65

GEOLOGY.

Mr. William Sharp on the Formation of Local Museums . . . .65
Mr. C. LvELLonthe Origin of the Tubular Cavities filled with Gravel and
Sand, called " Sandpipes," in the Chalk near Norwich ; with Addi-
tional Facts by J. B. Wigham, Esq 65

Mr. J. G. Marshall's Description of a Section across the Silurian Rocks
in Westmoreland, from the Shap Granite to Casterton Fell .... 67

Mr. J. A. Knipe on a Basaltic Dyke in the Vale of Eden 67

Rev. D. Williams on the Geological Horizon of the Rocks of S. Devon
and Cornwall, as regards that Section of the great Grauwacke Group
comprised in the counties of Somerset, Devon and Cornwall. ... 68
Mr, R. A. C. Austen's Note on the Organic Remains of the Limestones

and Slates of South Devon 69

Mr. Thomas Oram on the Economy of Fuel 69

Mr. C. Lyell on Remains of Mammalia in the Crag and London Clay of

Suffolk 69

Mr. W. Maerat on the Discovery of an Ichthyosaurus 70

VI CONTENTS.

Page
Mr. Jabez Allies on Marine Shells found in Gravel near Worcester . 70

Mr. W. R. Wylde on the Topography of Ancient Tyre 71

Mr. H. E. Strickland's Queries respecting the Gravel in the neighbour-
hood of Birmingham 71

Mr, BiNNEY on Microscopic Vegetable Skeletons found in Peat near
Gainsborough 71

Mr. R. I. MuRCHisoN on the Carboniferous and Devonian Systems of
Westphalia 72

Mr. G. Lloyd's General Outline of the Geology of Warvsrickshire, and a
Notice of some new^ Organic Remains of Saurians and Sauroid Fishes
belonging to the New Red Sandstone 73

Mr. BiNNEY on Fossil Fishes from St. George's Colliery near Manchester 75

Mr. O. Ward on the Foot-prints and Ripple-marks of the New Red
Sandstone of Grinshill Hill, Shropshire 75

Rev. W. BucKLAND on the Action of Acidulated Waters on the surface
of the Chalk near Gravesend 7Q

Mr. Robert Garner on an ceconomical Use of the Granitic Sandstone of
North Staffordshire 77

Mr. Jos. Brooks Yates on the rapid Changes which take place at the
entrance of the river Mersey, and the means adopted for establishing
an easy access to Vessels resorting thereto 77

Dr. G. H. Adams on Peat Bogs 78

ZOOLOGY AND BOTANY.

Mr. Edwin Lankester on the Formation of Woody Tissue .... 78
Mr. Edward Forbes's and Mr. John Goodsir's Notice of Zoological

Researches in Orkney and Shetland during the month of June 1839 . 79
Mr.JoHNGooDSiRon the Follicular Stage of Dentition in the Ruminants,

with some Remarks on that Process in the other Orders of Mammalia 82

Mr. Wilde on the Preparation of Fish 84

Mr. Edward Forbes and Mr. John Goodsir on the Ciliograda of the

British Seas 85

Dr. Bellingham on some new Species of Entozoa 86

Mr. Geo. Webb Hall on the Acceleration of the Growth of Wheat. . 86
Mr. William Felkin's Notice of an Experiment on the Growth of

Silk at Nottingham in 1839 87

George T. Fox's Observations on Whales, in connexion with the ac-
count of the Remains of a Whale recently discovered at Durham . . 89

Mr. Brand on the Statistics of British Botany 89

Dr. Pritchard on the Extinction of the Human Races 89

CONTENTS. VU

Page
Major-Gen. Briggs on the Cultivation of the Cotton of Commerce . . 90
Mr. W. Danson on the Introduction of a species of Auchenia into Bri-
tain, for the purpose of obtaining Wool 92

Rev. Charles C.Babington on some recentadditions to the English Flora 92
Professor R. Jones's Observations on an Apparatus for observing Fish

(especially of the family Salmonidse) in confinement 93

Mr. Robert Garner's Observations on Beroe pileus 93

MEDICAL.

Sir David J. H. Dickson's Abstracts of a remarkable case of Rupture

of the Duodenum, and of some other interesting Cases 94

Mr. R. Middlemore on the Treatment of Capsular Cataract . ... 96

Mr. R. Middlemore on an Operation for Artificial Pupil 96

Dr. Foville's Results of researches on the Anatomy of the Brain . . 97
Dr. Macartney on the means employed to suppress Haemorrhage from

Arteries 97

Dr. Peyton Blakiston on the Sounds produced in Respiration, and on

the Voice 100

Mr. Evans's Notice of an extraordinary case of Spina bifida .... 101
Dr. GoLDiNG Bird's Observations on Poisoning by the Vapours of burn-
ing Charcoal 101

Dr. Macartney on the Rules for finding with exactness the Position of
the Principal Arteries and Nerves from their Relation to the External

Form of the Body 102

Dr. Inglis on the Cause of the Increase of Small-Pox, and of the Origin

of Variola- Vaccinia 104

Mr. J, B. EsTLiN on the New Vaccine Virus of 1838 105

Dr. R. D. Thomson on Alkaline Indigestion 107

Mr. Joseph Hodgson on the Red Appearance of the Internal Coat of

Arteries 108

Mr. C. T. Coathupe on the Respiration of Deteriorated Atmospheres , 108
Dr. CosTELLo's Report of Ten Cases of Calculus treated by Lithotrity . 109
Mr. A. Nasmyth on the Cellular Structure of the Ivory, Enamel, and
Pulp of the Teeth, as well as of the Epithelium, and on some other in-
teresting points of Odontology 109

Dr. LuDwiG GiJTERBOCK on Instruments made from Softened Ivory. . 109

STATISTICS.

Mr. Wm. Langton's Report on the Educational condition of the County
of Rutland 110

Vlll CONTENTS.

Page

Mr. Francis Clark's Contributions to the Educational Statistics of
Birmingham, by a Local Committee Ill

Mr. W. R. Greg's Report on the State of the Working Classes in part of
Rutlandshire 112

Mr. Francis Clark's Contributions to the Commercial Statistics of
Birmingham, prepared by a Local Committee 114

Mr. Francis Clark's Contributions to the Medical Statistics of Bir-
mingham, prepared by a Local Committee 115

Mr. G. R. Porter's ' Suggestions in favour of the Systematic Collection
of the Statistics of Agriculture.' 116

Mr. R. W. Rawson on the Criminal Statistics of England and Wales . 117

Rev. Professor Powell on Academic Statistics, showing the proportion
of Students in the University of Oxford who proceed on to Degrees . 119

Mr. W. L. Wharton's Notice of the Progress of the Inquiries made by
the Committee instituted at the Meeting of the British Association in
Newcastle, when the sum of 50Z. was placed at the disposal of Mr.
Cargill, Mr. Wharton, Mr. Buddie, Mr. Forster, Mr. Wilson, and Mr.
Johnston, for the purpose of making inquiries into the Statistics of the
Mining Districts of Northumberland, Durham, and Yorkshire . . .120

Accountof theCirculatingLibraries in the Borough of Kingston-upon-HuU 120

Mr. Fripp on the condition of the Working Classes in the City of Bristol 121

MECHANICAL SCIENCE.

Mr. J. Scott Russell on the most Economical Proportion of Power to

Tonnage in Steam Vessels 124

Mr. E. Hodgkinson's Experiments to ascertain the Power of different

species of Wood to resist a force tending to crush them 125

Mr. Wm. Fairbairn's Experiments upon the effects of Weights acting

for an indefinite time upon bars of Iron 126

Mr. John Isaac Hawkins on Paving Roads and Streets with blocks of

Wood, placed in a vertical position 127

Mr. G. Cottam on the Marquis of Tweeddale's Patent Brick and Tile

Machine 128

Mr. G. Cottam's Description of a new Railway Wheel 128

Dr. Lardner's Notice of an Apparatus for Use in Working Railways . 129

Mr. GossAGE on a new Rotatory Steam-engine 129

Mr. Davies's Description of a Machine for cutting the teeth of Bevel

Wheels 129

Mr. Player on the application of Anthracite Coal to the Blast Furnace,

CONTENTS. IX

Page
Steam-engine boiler, and Smith's fire, in the Gwendraeth Ironworks

near Caermarthen 130

Mr. Jeffries on Warming and Ventilating 131

Mr. Beart's Account of a Method of Filtering Liquids 131

Mr. Dredge's Remarks on Bridge Architecture 131

Mr. John Britton on the Scientific principles, geometrical forms and
proportions, and the constructive skill manifested in the execution of
the Cathedrals and other large Churches of the Middle Ages ; with in-
cidental remarks on the symmetry, unity, and harmony, of ancient
Ecclesiastical Architecture. Illustrated by numerous Drawings . . 131

Mr. C. ViGNOLES on Percussion Boring of Tunnels 131

Mr. Wm. Carpmael on the method of rolling Dovetailed Grooves for

Railways 131

Mr. Thomas Parkin on a new construction of Wooden Railway Wheels. 131

Mr. Thomas Parkin on Railway Foundations 132

Dr. Ure on the Evaporative Calorific Powers of Fuel 132

Mr. W. J. Curtis on methods adapted to increase the security and ex-
tend the advantages upon Railroads 132

Mr. Stephen Geary on a new method of forming Fuel 132

Mr. King on a new Kitchen Range, with a Model 132

Mr. John Isaac Hawkins on folding Plates in Books and Maps for
the Pocket 132

NOTICES AND ABSTRACTS

MISCELLANEOUS COMMUNICATIONS
TO THE SECTIONS.

MATHEMATICS AND PHYSICS.

On a new case of Interference of Light. By Prof. Powell, F.R.S.

The author observed, that when a pvisra of one substance was op-
posed to another slightly differing in dispersive power, (as plate-glass
and oil of sassafras,) so as to produce a partial achromatism, in the co-
loured edges which appeared on either side of the white image of a nar-
row line of light, when viewed through a small telescope, there were
formed dark hands, about four or five being visible on each edge, pa-
rallel to the line of light.

The explanation is easy, when we consider that of the pencil of each
primary ray which enters the eye, (in breadth equal to the aperture of
the pupil,) the rays which have traversed greater thicknesses of the
first prism, pass through less thicknesses of the second ; and thus have
their retardations so compensated as to be in a condition to interfere
and produce the dark bands observed.

On the explanation of some Optical Phcenomena observed hy Sir David
Brewster. By Prof. Powell, F.R.S.

The experiments of Sir D. Brewster here referred to were those stated
at two preceding meetings of the Association, in which, on looking at
the spectrum, partly through, and partly over, the edge of a plate of
any transparent substance, it is seen marked by numerous dark bands.
If a plate of mica or selenite be cut with an edge sloping at an angle,

VOL. VIII. 1839. B

2 REPORT~1839.

compound bands are seen. In all eases the plate must advance /ro»z
the blue end of the spectrum ; the other way no bands are formed.
Hence, Sir D. Brewster considers the eiFect due to a new and peculiar
sort of polarity in the light of the spectrum.

It is allowed that the bands simply may be accounted for by interfe-
rence, but not the polarity.

The author has repeated and varied these experiments ; and con-
ceives that all the facts are easily explicable by the principle of inter-
ference, combined with the simplest considerations relative to the un-
dulatory course of the rays.

On fixing an opaque border, about the breadth of the pupil, on one
half of the edge of the plate, while the other is left bare, bands are
formed by the open part, but not by the opaque.

The inquiry was extended by using substances of different refractive
and dispersive powers, both as plates and prisms, as well as plates of
different thicknesses. According to these differences in the retardation,
the bands were closer or wider.

The smallest breadth of any plate (if of the requisite thickness) will
act. Hence the effect of the oblique edge is explained by a succession
of edges, and was imitated artificially, by combining several plates with
their edges slightly overlapping. Each plate gives its own set of bands,
and thus compound systems of superposed bands are produced.

Some plates are found with natural differences of thickness at some
points, on simply looking through which bands are seen.

These phaenomena, as well as those ascribed to polarity, appear per-
fectly explicable on the same principle as that applied in a previous
communication to the Section, viz. that the two pencils which interfere
are the two halves of the pencil of each ray which converges in the eye,
and whose breadth is equal to the aperture of the pupil ; the inter-
cepted half being that which has passed through the thinner part of
the prism, and this part is the least retarded.

The intercepted part has its retardation nearly equalized with that
of the other half of the pencil by the plate ; while the differences in
retardation for different rays of the spectrum are successively odd and
even multiples of the half wave-length.

On certain points in the Wave-theory as connected with Elliptic Polar-
ization, &c. By Prof. Powell, F.P.S.

The object of this communication is to draw attention to a discrepancy
between certain investigations relative to the theory of undulations,
when applied to the case of elliptically polarized light, as deduced
from the general equations of motion.

All the investigations of MM. Cauchy, Kelland, and others, set out
from certain general equations of motion, which are then reduced into
other forms, and being simplified by the express introduction of the
condition that certain terms vanish, are shown to be directly integrable
in forms which give the expression for a wave involving the relation
which explains the dispersion.

TRANSACTIONS OF THE SECTIONS. 3

If this condition (of the evanescence of certain terms,) is not ad-
mitted, the integration cannot proceed directly as in those investiga-
tions. But Mr. Tovey has shown that in this case, i. e. when those
terms are finite, certain forms will still be solutions : and these are pre-
cisely those for elliptically polarized light. — (Journal of Science, No. 71.)
It also appears from that paper and the author's (Phil. Trans. 1838,
Part II.) that the non-evanescence of those terms is the characteristic of
elliptic vibrations, as their evanescence is of rectilinear, and this implies
the unsymmetrical or symmetrical arrangement of the molecules of
aether as referred to the direction of the ray.

The discussion between Mr. Tovey and Mr. Lubbock (Journal of
Science, December 1837 and January 1838,) turns upon the proposition
involved in Fresnel's theory, " That every system of molecules (consti-
tuted as here supposed) has at every point three axes of elasticity : and
that if these be taken as axes of co-ordinates, the evanescence of the
terras above referred to is a necessary consequence." This proposition
is essential to the whole investigation of the wave-surface ; and thus it
would follow, that in all media we may assume the axes so that this
condition is fulfilled.

This then appears irreconcileable with the characteristic of elliptic
vibrations before laid down. The author has followed up the subject
in a paper which will appear in the Philosophical Transactions.

Remarks on M. Daguerre's Photogenic Process.
By Fox Talbot, Esq., F.R.S.

The first part of M. Daguerre's process consists in exposing a silver
plate to the vapour of iodine, by which it becomes covered with a
stratum of iodide of silver, which is sensitive to light. Mr. Talbot
stated that this fact had been known to him for some time, and that it
formed the basis of one of the most curious of optical phsenomena,
which, as it did not appear to have been observed by M. Daguerre, he
would describe to the meeting. Place a small particle of iodine, the
size of a pin's head, on a plate of silver, or on a piece of silver-leaf
spread on glass. Warm it very gently, and you will shortly see the
particle become surrounded with a number of coloured rings, whose
tints resemble those of Newton's rings. Now, if these coloured rings
are brought into the light, a most singular phaenomenon takes place ;
for the rings prove to be sensitive to the light, and their colours change,
and after the lapse of a short time their original appearance is quite
gone, and a new set of colours have arisen to occupy their places.
These new colours are altogether unusual ones ; they do not resemble
anything in Newton's scale, but seem to conform to a system of their
own. For instance, the first two colours are, deep olive green, and deep
blue inclining to black, which is quite unlike the commencement of
Newton's scale. It will be understood that the outermost ring is here
accounted the first, being due to the thinnest stratum of iodide of silver,
furthest from the central particle. The number of rings visible is
sometimes considerable. In the centre of all, the silver-leaf becomes

R 9

4 REPORT — 1839.

white and semi-transparent, like ivory. This white spot, when heated,
turns yellow, again recovering its whiteness when cold : from which it
is inferred to consist of iodide of silver in a perfect state. The coloured
rings seem to consist of iodide of silver in various stages of develop-
ment. They have a further singular property, which, however, has not
been sufficiently examined into. It is as follows : It is well known that
gold-leaf is transparent, transmitting a bluish green light ; but no other
metal has been described as possessing coloured transparency. These
rings of iodide of silver, however, possess it, being slightly transparent,
and transmitting light of different colours. In order to see this, a small
portion of the film should be isolated, which is best done by viewing
it through a microscope. Mr. Talbot said, that he had considered the
possibility of applying a silver plate thus combined with iodine to the
purpose of photogenic drawing, but he had laid it aside as insufficient
for that purpose, on account of its sensitiveness appearing to be much
inferior to that of paper spread with chloride of silver, and therefore in
an equal time it takes a much feebler impression. Now, however, M.
Daguerre has disclosed the remarkable fact, that this feeble impression
can be increased, brought out, and strengthened, at a subsequent time,
by exposing the plate to the vapour of mercury. Another experiment
was then related, in which a particle of iodine was caused to diffuse its
vapour over a surface of mercury. In order to this, a copper plate was
spread over with nitrate of mercury, and then rubbed very bright, and
placed in a closed box along with a small cup containing iodine. The
result was, a formation of Newton's rings of the greatest splendour and
of a large size. But they did not appear to be in any degree sensitive
to light.

The next point of M. Daguerre's process is, the exposure of the
picture to the vapour of mercury ; and this is by far the most enig-
matical part of the whole process. For, he states that if you wish to
view the picture in the usual manner, that is, vertically, you must hold
the plate inclined to the vapour at an angle of 45", and vice versa.
Now this is something altogether extraordinary ; for who ever heard of
masses of vapour possessing determinate sides, so as to be capable of
being presented to an object at a given angle ? From the hasty consi-
deration which he had been able as yet to give to it, his first impression
was, that this fact bore a certain analogy to some others which he
would mention. If a piece of silver-leaf is exposed to the vapour of
iodine, however uniform the tension of the vapour may be, yet it does
not combine uniformly with the metal, but the combination commences
at the edge of the leaf and spreads inwards, as is manifested by the
formation of successive bands of colour parallel to the edge. This is
not peculiar to silver and iodine, but occurs when other metals are ex-
posed to other vapours : not always with entire regularity, but there is
a tendency to combine in that way. A possible explanation is, that
this is due to the powerful electrical effect which the sharp edges and
points of bodies are known to possess ; in fact, that electricity is either
the cause or the attending consequence of the combination of vapour
with a metallic body. Again, if a minute particle of iodine is laid on

TRANSACTIONS OF THE SECTIONS. 5

a steel plate, it liquefies, forming an iodide of iron, and a dew spreads
around the central point. Now, if this dew is examined in a good
microscope, its globules are seen not to be arranged casually, but in
straight lines along the edges of the minute striae or scratches which
the microscope detects even on polished surfaces. This is another
proof how vapour is attracted by sharp edges, for the sides of those
striae are such. Whether or not these facts had any relation to that
observed by M. Daguerre, of the action of vapour at an angle of 45°,
Mr. Talbot did not pretend to say, but thought them worthy of being
mentioned to the Section.

He observed, that it had been repeatedly stated in the Comptes
rendus of the French Institute, that M. Daguerre's substance was
greatly superior in sensitiveness to the English photogenic paper. It
now, however, appeared that this was to be understood in a peculiar
sense, inasmuch as the first or direct effect of the French method was
very little apparent, and was increased by a subsequent process. This
circumstance rendered it difficult to institute a direct experimental com-
parison between them. If it could be accomplished, he doubted whether
M. Daguerre's substance would be found much more sensitive than his.
The present degree of sensitiveness of the photogenic paper was stated
to be as follows : it will take an impression from a common argand
lamp in one minute, which is visible though weak. In ten minutes the
impression is a pretty strong one. In full daylight the effect is nearly
instantaneous. M. Arago had stated that M. Daguerre had obtained
some indications of colour. Mr. Talbot thereupon referred to his paper
to the Royal Society, read January 1839, and published in the Athe-
TKBum (No. 588), wherein he had stated the same thing. Since then,
more considerable effects of colour have been noticed. In copying a
coloured print the colours are visible on the photograph, especially the
red, which is very distinct. Some descriptions of photogenic paper
show this more than others ; but no means have yet been found of
fixing those colours, and sunshine reduces them all to an uniformity of
mere light and shade. Sir John Herschel has formed images of the
solar spectrum, in which the change of colour is seen from end to end
of the spectrum, but most clearly at the red end. Mr. Talbot then
mentioned a kind of photogenic pictures which a,fford a very capricious
phaenomenon. The objects are represented of a reddish colour on a
white ground, and the process leaving the pictures in such a state that
they are neither ^a;ec?, nor yet the contrary, but in an intermediate
state; that is to say, that when they are exposed to sunshine they
neither remain unchanged (as fixed pictures would do), nor are they
destroyed (as unfixed pictures would be) ; but this singularity occurs,
that the white ground remains unaltered, while the colour of the object
delineated on it changes from reddish to black with great rapidity, after
which no further change occurs. These facts (he thought) serve to
illustrate the fertility of the subject, and show the great extent of yet
unoccupied ground in this new branch of science.

6 REPORT— 1839.

On an Apparatus for obtaining a numerical estimate of the Intensity of
Solar Light, at different periods of the day, and in different parts of
the globe. JBy Prof. Daubeny, F.R.S.

The contrivance, by which it was proposed to effect this object, was
to consist of a sheet of photogenic paper, moderately sensible, rolled
round a cylinder, which, by means of machinery, would uncoil at a given
rate, so as to expose to the direct action of the solar rays, for the space
of an hour, a strip of the whole length of the sheet, and of about an
inch in diameter. Between the paper and the light was to be interposed
a vessel, with plane surfaces of glass at top and bottom, and in breadth
corresponding to that of the strip of paper presented. This vessel,
being wedge-shaped, was fitted to contain a body of fluid of gradually
increasing thickness, so that, if the latter were calculated to absorb light,
the amount of it intercepted would go on augmenting from one extre-
mity of the vessel to the other. Hence it was presumed, that any dis-
coloration that might arise from the action of light would proceed along
the surface of the paper to a greater or less extent, according as the
intensity of the sun's light was such as enabled it to penetrate through
a greater or lesser thickness of the fluid employed. In order to register
the results, nothing more would be required than to measure, each
evening, by means of a scale, how many degrees the discoloration had
extended along the surface of the paper which had been exposed to
light, during each successive hour of the preceding day. To render
the instrument self-registering, some contrivance for placing the paper
always in a similar position with reference to the sun, must of course
be superadded. The object of this contrivance differed from that aimed
at by Sir J. Herschel in his Actinometer, being intended as a measure
of the aggregate effect of the solar intensity at the period (be it long
or short) during which the paper was submitted to its influence; whereas
the Actinometer merely measures the intensity at the moment the ob-
servation is made. The interposition of an absorbing fluid has at least
this advantage, that it enables the observer to estimate the relative in-
tensity, by marking the point at which the paper ceases to be discolour-
ed, of which the eye is able to judge more exactly, than it could do, of
the relative darkness of shade produced on paper which had been ex-
posed without protection to light of different degrees of brilliancy.

Notice respecting the Use of Mica in polarizing Light.
By Prof. Forbes, F.R.S.

The author explained the method of preparing mica used by him,
since 1836, for the polarization of heat and light. The mica is exposed
for a short time to an intense heat in an open fire, by which the laminae
are so subdivided, that a pellicle of extreme thinness contains a suffi-
cient number of reflecting surfaces to polarize very completely the
light or heat transmitted through it at a certain degree of obliquity.
He next stated, that being struck by the resemblance to metallic lustre
which the mica acquires in this process, he had examme ( aiso in 1836)

TRANSACTIONS OF THE SECTIONS. 7

some of its leading properties with regard to liglit, and he found, 1st,
that the light reflected from a plate of mica so prepared, (which light
is very intense,) is but feebly polarized in the plane of incidence ; and
2nd, that the reflection so far resembles that at metallic surfaces, that
when plane-polarized light is reflected from it, the plane of reflection
being inclined to that of primitive polarization, the light is found to be
elliptically polarized. The latter fact he stated to be in a great measure
explained theoretically by a remark made by Professor Lloyd, to whom
he had mentioned the experiment. The observation, and also the
theory of it, cannot fail, he thinks, to be important in illustrating the
nature of metallic reflection, which is at present so actively discussed.

On the bending of silvered Plate Glass into Mirrors.
By James Nasmyth.

The author described a simple, and, so far as he is aware, original
mode of forming concave mirrors of vast size for reflecting telescopes
from disks of silvered plate glass, which by means of the pressure of
the atmosphere, he bends at pleasure in a cold state to any required
degree of curvature (within reasonable limits). Mr. Nasmyth brought
to the meeting a disk of silvered plate glass, 3 ft. 3 in. diameter,
which he could at pleasure bend and unbend into a concave mirror, by
simply withdrawing some of the air from behind its surface ; the disk
of plate glass being cemented round the edge on a circular plate of
cast iron, so that the air-tight cavity thus formed behind the outward
surface of the glass permits the pressure of the atmosphere to act and
press it into a concave mirror, the instant any portion of the air behind
is withdrawn. Any required degree of curvature can be retained by
simply preventing the return of the air behind by means of a stop-
cock.

On Photometry, or a mode of measuring diffuse daylight comparatively,
at any time and place. By Dr. Andrew Ure.

When lights of different intensities have the same quality of tint, or
tone of colour, they may be measured relatively to each other, by the
relative depths of shadow which they project upon a white wall or
screen, from an opaque body interposed. When the tint of the light,
however, is very different, as with the bluish flame of gas, the vivid
white of an argand lamp fed with oxygen (called the Bude light), or
the gray light of the sky, it becomes very difficult to measure the re-
spective intensities of such lights, by comparing the shadows which
they project, with the shadows projected from the flame of a standard
wax caudle, or a mechanical lamp. Dr. Ure experienced this diffi-
culty, of late, upon two interesting occasions. The first was in trying
to measure the relative illuminating powers of the Bude light, in sub-
serviency to my examination before the Select Committee of the House
of Commons on lighting the House. The second was in estimating

8 REPORT— 1839.

the degree of obscuration of daylight, produced by a high wooden wall
or hoard, recently erected in a garden behind two valuable houses in
George Street, Hanover Square, London. In the latter case he had
recourse to a photometric plan, which appears to be free from all am-
biguity or source of error. The chloride and several other salts of
silver are so very sensitive to light, as to take a dark grey tint from
exposure to diffuse daylight in a very short time. When the aspect of
the sky continues uniform for two or three hours, paper imbued with
the nitrate, carbonate, chloride, or phosphate of silver, will assume a
depth of grey or brown tint proportional to the time of its free exposure
to the day. Availing himself of this principle. Dr. Ure simultaneously
placed pieces of paper so prepared, in the apartments subject to the
darkening influence of the wall, and in apartments of the adjoining
house, not under that influence. The papers which enjoyed the free
aspect of the sky, having assumed a decided depth of hue in half an
hour, he folded them up from the light, and proceeded to watch the
papers placed opposite to the windows less or more obscured, till he
observed them to take the same depth of tint. The relative degrees
of diurnal illumination in different apartments of any house — in diffe-
rent countries — or on different days in the same place or country, may
thus be accurately measured and permanently registered by a series of
photogenic impressions of any form, which will exhibit the progressive
depths of tint, after an exposure during a certain number of minutes to
diffuse daylight ; care being always had to prevent the direct or reflected
impulsion of the sunbeams. The tints thereby produced being fixed
by water of ammonia, hyposulphite of soda, or any of the well-known
photogenic expedients, will serve as standards of comparison to enable
us to estimate the vivacity of daylight in any region of the globe, from
the time in which paper similarly prepared with a standard salt of silver,
acquires from exposure to daylight the same hue. And since the com-
parison of tints may be made with considerable precision by an expe-
rienced eye, this photometric method may prove a valuable addition to
the scientific resources of the meteorologist.

On the use of the Oxy-Hydrogen Microscope in exhibiting the
phcBnomena of Polarization. By J. F. Goddard.

In the description of Mr. Goddard'spolariscope, published in the Trans-
actions of the Society of Arts, the polarizing mirror will be found to be
placed after the third condensing lens, which is only used with the high
magnifying powers ; this arrangement he was compelled to adopt, as the
microscope which had been previously made would not admit of any
other. But he has since had one constructed, in which he could intro-
duce every improvement that his experience suggested ; and one of
the most important was to place the polarizing mirror much nearer the
light, so that he can now use, with the polariscope, the lowest magnify-
ing powers, and consequently exhibit much larger illustrations and de-
signs in selenite ; also the different forms of unannealed glass ; and not

TRANSACTIONS OF THE SECTIONS. 9

only greatly to extend the variety of experiments and illustrations, but
much to improve the splendour of them all. The most important of
these is in the analysing part of the apparatus. Having obtained an
unusually fine plate of tourmaline, he tried various experiments with it
and other means, from which it appears much more can be done with a
bundle of films of mica, when bleached and properly constructed for
analysing, than can be effected by any tourmalines, however good.
Prof. Forbes, in his experiments on the polarization of heat, first em-
ployed bundles of bleached mica, — his process of bleaching which, by
heat, he has already published ; but, for experiments on light, the pro-
cess must not be carried so far, and requires to be conducted with great
care, for when raised beyond a bright red heat, the mica blisters and
becomes unfit for these purposes, being broken into very small portions,
that are incapable of transmitting a clear and distinct image, from the
number of unequal refractions which the light undergoes in different
parts : whilst the heat, if properly regulated, will drive off all the colour
of the mica, without its being blistered; it may afterwards be easily
divided into sufficiently thin laminae, so that about eighteen of them,
placed between two plates of thin glass (to protect them from being
scratched), form the best means of analysing, and allowing both
complementary images may be shown at the same time, — by using
two screens, one to receive the refracted image, and the other to receive
the reflected image, — thus furnishing the means of exhibiting, with
singular effect, all the beautiful phsenomena of polarized light.

A Letter to the Rev. William Whewell, President of the Section on th^
Chemical Action of the Solar Rays. By Sir J. F. W. Herschel
Bart., F.R.S. '

Slough, Aug. 28, 1839.
My dear Sir, — May I take the liberty of requesting that you will
mention to the Physical Section of the British Association a very re-
markable property of the extreme red rays of the prismatic spectrum,
which I have been led to notice in the prosecution of my inquiries into
the action of the spectrum on paper, rendered sensitive to the chemical
rays by Mr. Talbot's process, or by others of my own devising.

The property in question is this, — That the extreme red rays, (such I
mean as are insulated from the red of the spectrum by a dark blue
glass coloured by cobalt, and which are not seen in the spectrum un-
less the eye be defended by such a glass from the glare of the other
colours,) not only have no tendency to darken the prepared paper, but
actually exert a contrary influence, and preserve the whiteness of paper
on which they are received when exposed at the same time to the action
of a dispersed light sufficient of itself to produce a considerable im-
pression. I have long suspected this to be the case, from phsenomena
observed in taking photographic copies of engravings ; but having at
length obtained demonstrative evidence of the fact, I think this may
not be an improper opportunity to announce it to the President of the
Physical Section of the British Association.

REPORT — 1839.

When a slip of sensitive paper is exposed to a highly concentrated
spectrum, a picture of it is rapidly impressed on the paper, not merely
in black, but in colours, a fact which I mentioned nearly two months
ago, and which observation of mine seems to have been alluded to
(though in terms somewhat equivocal,) by M. Arago in his account
of Daguerre's process. In order to understand what follows, it will be
necessary to describe the colours so depicted. The red is tolerably
vivid, but is rather of a brick-colour than a pure prismatic red. And
what is remarkable, its termination falls materially short of the visible
termination of the spectrum. The green is of a sombre, metallic hue,
the blue still more so, and rapidly passing into blackness. The yellow is
deficient. The whole length of the chemical spectrum is not far short
of double that of the luminous one, and at its more refrangible end a
slight ruddy or pinkish hue begins to appear. The place of the extreme
red, however, is marked by no colour, thus justifying, so far, the ex-
pression which M. Arago is reported to have used in speaking of my
experiments — " Le rayon rouge est seul sans action."

It is impossible in this climate to form a brilliant and condensed
spectrum without a good deal of dispersed light in its confines ; and
this light, if the exposure of the paper be prolonged, acts, of course,
upon every part of its surface. The coloured picture is formed, there-
fore, on a ground not purely white, but rendered dusky over its whole
extent, with one remarkable exception, — viz. in that spot where the ex-
treme red rays fall, the whiteness of which is preserved, and becomes
gradually more and more strikingly apparent, the longer the exposure
and the greater the consequent general darkening of the paper.

In the figure, R V is the luminous, and a d the chemical spectrum.
Of this the portion a y is white, its middle corresponding to the extreme
red of the luminous spectrum ; y ^ is red ; ^ e green, passing rapidly
through a shade of extremely sombre blue e ^ into black, which occu-
pies the whole space from ^ to rj.

The above is not the only singular property possessed by the ex-
treme red rays. Their action on paper already discoloured by the
other rays is still more curious and extraordinary. When the spectrum
is received on paper already discoloured slightly by the violet and blue
rays only, they produce, not a white, but a red impression, which, how-
ever, I am disposed to regard as only the commencement of a process

TRANSACTIONS OF THE SECTIONS. 11

of discoloration, which would be complete if prolonged sufficiently.
For I have found that if, instead of using a prism, a strong sunshine is
transmitted through a combination of glasses carefully prepared so as
to transmit absolutely no ray but that definite red at the extreme of
refrangibility, a paper previously darkened by exposure under a green
glass has its colour heightened from a sombre neutral tint to a bright
red ; and a specimen of paper rendered almost completely black by ex-
posure to daylight, when exposed for some time under the same glass,
assumed a rich purple hue ; the rationale of which effect I am disposed
to believe consists in a very slow and gradual destruction, or stripping
off as it were, of layers of colour deposited or generated by the other
rays, the action being quicker on the tints produced by the more refran-
gible rays in proportion to their refrangibilities.

It seems to me evident that a vast field is thus opened to further in-
quiries. A deoxidizing power has been attributed to the red rays of
the spectrum, on the strength of the curious experiments of WoUaston
on the discoloration of tincture of guaiacum, which ought to be re-
peated ; but in the sensitive papers, and still more in Daguerre's mar-
vellous ioduretted silver, we have reagents so delicate and manageable,
that everything may be expected from their application.

I remain, my dear Sir,

Your very obedient servant,

J. F. W. Herschel.

P.S. — I inclose a picture of the spectrum formed as above described.
It must be viewed by lamp- or candle-light — not being fixed. In this
way it may be examined by any number of persons, which by daylight
would be impracticable, as a few minutes' exposure would obliterate all
its peculiar characters. The larger pencil dot indicates the centre of
the sun's image formed by the extreme red rays, at which point the
maximum of whiteness will be observed to occur.

Prof. Whewell communicated some tide observations, forwarded to
him by the Russian Admiral Liitke. These observations supplied —
first, the tide hours of various places on the coasts of Lapland, the
White Sea, the Frozen Sea, and the coasts of Nova Zemlia. These
observations enable us to follow the progress of the tide-wave further
than had hitherto been done. Mr. Whewell's map of Cotidal Lines
(the second approximation contained in the Phil. Trans. 1836,) follows
the tide only as far as the North Cape of Norway. Prof. Whewell
stated, that he was informed by Admiral Liitke, that in the Frozen Sea
east of Nova Zemlia there is little or no perceptible tide. The obser-
vations communicated by Admiral Liitke, offered various other results,
and especially the existence of the diurnal inequality in the seas ex-
plored by Russian navigators, as on the coast of Kamscatcha, and the
west coast of North America.

Prof. Whewell made some observations on Capt. Fitzroy's views of
the tides. In the account of the voyage of H.M.SS. Adventure and

12 REPORT — 1839.

Beagle, just published, there is an article in the Appendix, containing
remarks on the tides. Captain Fitzroy observes, that facts had led him
to doubt several of the assertions made in Mr. Whewell's memoir, pub-
lished in the Philosophical Transactions, 1833, and entitled 'Essay
towards a First Approximation to a Map of Cotidal Lines.'* — (Appendix,
p. 279.) Prof. Whewell stated, that he conceived that douhls, such as
Captain Fitzroy 's, are reasonable, till the assertions are fully substan-
tiated by facts. Captain Fitzroy has further offered an hypothesis of
the nature of the tidal motion of the waters of wide oceans, diiferent
from the hypothesis of a progressive wave, which is the basis of Prof.
"Whewell's researches. Captain Fitzroy conceives that in the Atlantic
and the Pacific the waters oscillate laterally between the eastern and
western shores of these oceans, and thus produce the tides. This sup-
position would explain such facts as this, that the tide takes place
along the whole west coast of South America at the same time ; and
the supposition might be so modified as to account for the absence of
tides in the central part of the ocean. Prof. Whewell stated, that he
was not at all disposed to deny that such a mode of oscillation of the
waters of the ocean is possible. Whether such a motion be consistent
with the forces exerted by the sun and moon, is a problem of hydrody-
namics hitherto unsolved, and probably very difficult. No demonstra-
tive reason, however, has yet been published, to show, that such a
motion of the ocean waters may not approach more nearly to their
actual motion, than the equilibrium theory, as usually applied, does.
When the actual phaanomena of the tides of the Atlantic and Pacific
have been fully explored, if it appear that they are of the kind supposed
by Captain Fitzroy, it will be very necessary to call upon mathemati-
cians to attempt the solution of the hydrodynamical problem, either in
a rigorous or in an approximate shape.

On the best Positions of three Magnets, in reference to their mutual action.
By the Rev. Professor Lloyd, F.R.S.

It is a problem of much importance, in connexion with the arrange-
ment of a magnetical observatory, to determine the relative position of
the magnets in such a manner, that their mutual action may be either
absolutely null, or at least readily calculable. Such was stated by
the author to be the object of the present investigation. In the
case of two horizontal magnets, one of which (intended for obser-
vations of declination) is in the magnetic meridian, and the other (used

* Among the points which I could not establish in my own mind, by appeal to fac^s,
were: — " The tides of the Atlantic are, at least in their main features, of a derivative
kind, and are propagated from south to north ;" "that the tide-wave travels from the
Cape of Good Hope to the bottom of the Gulf of Guinea, in something less than four
hours; that the tide-wave travels along this coast (American) from north to south, em-
ploying about twelve hours in its motion, from Acapulco to the Strait of Magalhaens;"
" from the comparative narrowness of the passage, to the north (of Australia), it is al-
most certain that these tides must come from the southern end of the continent." "The
derivative tide, which enters great oceans (North and South Pacific) from the south-
east, is diffused over so wide a space that its amount is greatly reduced."

TRANSACTIONS OP THE SECTIONS. 13

for observations of horizontal intensity) is in the perpendicular plane,
there is nothing to compensate the action of each magnet on the other.
The best thing that can be done, then, is to determine the position
of the second magnet in such a manner, that the direction of its action
on the first shall coincide with the magnetic meridian. In such case,
the mean direction of the first magnet will be undisturbed by the second ;
and, as to the variations of the direction, it is manifest that they will
be thereby increased or diminished in a given ratio ; so that the true
variations will be obtained simply by multiplying by a constant coeffi-
cient. The reciprocal action of the first magnet on the second, however,
will not take place, either in the magnetic meridian, or in the plane
perpendicular to it ; so that the second magnet is necessarily disturbed.
The case is different when a third magnet is introduced. When this
magnet \s, fixed, we have only to consider the disturbing forces exerted
upon the other two magnets, and the conditions of equilibrium of these
forces are easily shown to be expressed by four equations, containing
four arbitrary angles ; and the equilibrium is accordingly attainable by
suitably determining the position of the three magnets, whatever be
their relative intensities. The third magnet may, however, be a
moveable one, and its movements serve to exhibit the changes of one
of the magnetic elements. In the Dublin Magnetical Observatory this
magnet is employed in the determination of the vertical cowpotient of
the magnetic force. It is a bar supported on knife-edges, capable of
motion in a vertical plane, and brought into the horizontal position by
means of a weight. The three magnets being in the same horizontal
plane, it is manifest that the action of the first and second on the third
must take place in that plane ; and if this force be resolved into two,
one in the direction of the axis of the magnet, and the other perpendi-
cular to it, the latter component can have no effect on the position of
the magnet, being at right angles to the plane in which it is constrained
to move ; and, as to the former, it manifestly cannot affect the mean
position of the magnet, but merely augments or diminishes the devia-
tions from that position in a given ratio. The destruction of this force,
in the direction of the axis of the third magnet, introduces d, fifth con-
dition of equilibrium ; and, as there are but four arbitrary angles, it
follows that complete equilibrium is not attainable, except for deter-
minate values of the relative forces of the magnets. We may, however,
without inconvenience, dispense with one of the conditions of equili-
brium ; and, the other form being fulfilled, the disturbing action upon
two of the magnets will be completely balanced, while the effect of that
exerted upon the third may be at once eliminated from the results, by
altering in a suitable manner the constant in the formula of reduction.
The author then proceeded to consider the cases in which the four
angles were not all arbitrary, some circumstance connected with the
locality determining one or more of these quantities, or establishing
one or more relations among them. He pointed out, in such cases, the
conditions most important to be fulfilled ; and gave examples of the
solution in some particular instances, such as where the three magnets
are in the same right line, &c.

14 REPORT — 1839.

In reply to a question from the President, Mr. Lloyd briefly explained
to the Section the arrangement of the portable observatory, adopted by
Captain J. Ross, in his preparations for the Antarctic expedition. It is
so constructed as to form, either three small separate rooms, or one
large one ; the former arrangement being desirable at places where
the dip is nearly 90°, and where, consequently, the horizontal directive
force is very small, and the disturbing action of the magnets on one
another, relatively great. The parts are put together with copper
fastenings ; and the whole is so arranged, as to occupy a very small
bulk when in pieces, and to be capable of being put together with
quickness and security.

Meteorological Observations made at Great Malvern during the years
1835, 1836, 1837, and 1838. By Mr. Addison.

In these tables, the mean results for every month, and for the vari-
ous seasons, and for each year, have been computed. Great Malvern,
in Worcestershire, has an elevation of about 500 feet. Great diifer-
ences of temperature have been observed within short distances — the
lower localities being frequently very much colder than the more elevated
ones. Thus on three or four occasions drops of rain have fallen, with
the thermometer in the vale at 24°. The dew-point is subject to greater
variations, and frequently falls to a much lower point in the higher
situations, except when the temperatures are very different ; it then
appears, that the dew-point is frequently very low in the cold, misty,
foggy air of the valley. From these tables it appears that the mean
temperature of Malvern is 4;7'7 ; the highest annual mean is 49*1, in
1835 ; and the lowest ^6' 5, in 1838 ; being a diiference of 2*5 between
these two years. The mean barometer is 29*386 ; and the mean dew
point, at 9 a.m., 43'7. When the mean temperature of the year is
higher, the mean dew-point also is higher ; thus, in 1835, mean tempe-
rature, 49*1 — mean dew-point, 44*7 ; in 1838, mean temperature, 46*5
— mean dew-point, 42*4. In 1837, the lowest temperature of the year
occurred in the night of the 25th of March. The maximum of the
barometer, in three out of the four above-mentioned years, occurred in
the first week of January. The minimum of the barometer, in three
out of four years, occurred in November. The range of temperature
during the four years, from 9° on the 20th of January 1838, to 84° on
the of 5th July 1836, is 75°. The range of the barometer, from 28*010,
on the 29th of November 1838, to 30*228, on the 14th of October 1837,
is 2*2 inches. The aurora borealis was observed in November, 1835;
in May, 1836 ; in February, March, April, August, October, and
November, 1837; and in September, 1838. A remarkable noise was
heard at 4 p.m. on the 4th of August, 1835, like a loud clap of thunder,
the air at the time being quite free from cloud, and the sun hot and
brilliant. Very high winds, with the air at the dew-point, occasion a
large evaporation.

TRANSACTIONS OF THE SECTIONS.

On certain Meteorological Phcenomena m the Ghats of Western India.
Btj Col. Sykes, F.R.S.

In the proceedings of the Physical Section at the meeting at New-
castle, the incidental mention of the annual fall of very many feet of
rain in certain localities of India, instead of a few inches, as is the case
in Europe, caused, I was told, some surprise, and the expression of a
doubt whether the fact had been ascertained with sufficient precision,
and by competent persons. I was not present on the occasion alluded
to, but the doubt having been brought to my notice subsequently, I
lost no time in applying toafriend to procure for me the official meteoro-
logical records kept by order of the government of Bombay at the
convalescent station of Mahabuleshwar, which records I knew would
afford sufficient evidence to remove all doubts, at least so far as related
to one locality ; and I have now the pleasure of submitting the abstract
of the Meteorology for 1834; the observations being made by Dr.
Murray, the medical officer in charge of that station. The station is
situated lat. 17° 58' 53" N. and long. 73° 29' 50" W., near the western
scarp of the Ghats, or mountain chain extending from Surat to Cape
Comorin, and varying from 1000 to 8000 feet in height. The eleva-
tion of the table-land at Mahabuleshwar averages 4500 feet. The tem-
perature of a spring is 65*5 Fahr., and the mean temperature of the
air for three or four years is nearly the same. There is a good deal of
forest along the Ghats, but in belts and patches, so that the wood can
have little effect on the phasnomena which I am about to describe. In
this table-land is the soui-ce of the celebrated Kistnah river, which
runs across the peninsula.

The following table shows the state of the thermometer, fall of rain,
&e., at the station :

Months.

il
^1

Fall of
Rain in
Inches.

Direction and force of the Wind.

January ...
February...
March

65-7
67-5
74-0

74-4

73-9
66-3
64-9

65-3
65-0
65-5
63-5
62-3

71-2
73-7
81-7
82-2

80-6
69-3
66-6
66-9
66-4

69-4
69-5
68-4

60-2
61-3
66-4

66-7
67-3
63-4
63-2

63-8

63-6
61-7

56-2

12-4
15-3
15-5 {
13-3

5-9
3-4
3-1

2-8

77
12-0
13-2 {

0-25

Two light \
showers J
0-16
32-03
118-60
75-91
65-97

One light;
shower J

A.M.

E. light.

E.N.E. light.

N.E. light.

rW.N.W.&S.W.

i fresh.

S.W. high and fresh.

S.V^^. strong.

S.W. high.

S.W. fresh.

N.E. fresh.

E.N.E. high.

E.N.E. fresh.

P.M.

E.N.E. & W. light.

W.N. W. light.
W. & N.W. fresh.

W. light.

W.N.W. & S.W.

fresh and strong.

S.W. high and fresh.

S.W. strong.

S.W. high.

S.W. fresh.

/ N.E. & S.W. light.

i E.N.E. fresh.

E.N.E. fresh.
E.N.E. & W. light.

May.

June

July ... .

August

September..
October ...
November .
December .

Mean...

67-3

72-1

62-6

9-5

302-21

16 REPORT— 1839.

Hence it appears that the mean temperature of 1834 was 67'3 Fahr.,
that of the hottest month (April) 74*4', that of the coldest month (Dec.)
62*3 ; the mean maximum (April) 82*2, and the mean minimum
(Dec.) 56*2. The mean variation was greatest in April, 15*5, and
least in September, 2*8 ; and the mean variation for the year was only
9*5. The fall of rain was prodigious, being equal to 25 feet 2 inches,
and this enormous mass of water fell almost entirely in the months of
June, July, August and September. General Lodwick, late president
at the court of Sattarah, who transmitted to me the official register,
says, " I send to you a copy of Dr. Murray's meteorological table.
The inches of rain are no less than 302*21. This will astonish the
philosophers, but it would do more than astonish them, had they the
opportunity of seeing and hearing the rain fall in torrents through a
dense fog or mass of clouds which lie upon the ground for perhaps
six weeks together, with a temperature by no means cold, and with little
variation." The excessive fall of rain along the line of the Ghats does
not seem to be incompatible with health, for the military detachment
stationed permanently at Mahabuleshwar is not characterized by any
unusual sickness ; and the statistical returns of the population on the
hills are as healthy as those of the table-lands to the eastward. It now
remains to notice some striking facts on the western side of the pen-
insula. The quantity of rain that falls differs exceedingly between
the coast, the Ghats within fifty miles of the coast, and the table-
land eastward of the Ghats. The mean at Bombay is 80-69. Dr.
Murray shows a fall in the hills, at the elevation 4500 feet, of 302
inches, and my records at Poonah give a mean annual fall of 23*43
inches. The solution of the causes of the anomalous fall of rain does
not offer any considerable difficulties. The enormous mass of vapour
taken up from the Indian Ocean on approaching India, does not appear
to have its upper surface at a greater elevation than five or six thousand
feet, while the stratum is of great thickness ; and I can bear testimony
to its lower surface being below fifteen or eighteen hundred feet. The
temperature of the air over the equator is necessarily very high, and
its capacity for the support of aqueous vapour is proportioned to its
temperature. The vapour is converted into rain, as it is driven into
air of lower temperature ; and, as the temperature gradually lowers
proceeding to the north, and approaching the land, it follows, that out
at sea, and along shore, with equal supplies of vapour, a less quantity
of it would be converted into rain eastward. With respect to the pro-
digious fall at Mahabuleshwar and along the Ghats, it may be accounted
for by the supposition that the monsoon vapour being of low elevation
and high temperature, is driven against the mural faces, and up the
chasms of the Ghats, into higher regions, and into a colder atmosphere,
and is thus immediately converted into rain. The paucity of rain forty
or fifty miles eastward of the Ghats, results from the comparatively
small quantity of vapour which escapes from the cold belt of air
through which it is forced to pass in the hills.

TRANSACTIONS OF THE SECTIONS. I/

An Account of some Indications of the Anemometers erected at Plymouth
and Birmingham. By Follett Osler.

An anemometer and rain-gauge, similar (said Mr. Osier) to the one
that I constructed about three years ago, and which has, since that period,
been at work at the Birmingham Philosophical Institution, was erected
at Plymouth, a few months ago, by order of the British Association, and
placed under the supeiintendence of Mr. Snow Harris. Having just re-
ceived the registers of this instrument, I shall take a cursory review of a
few of them, in conjunction with those obtained at Birmingham. I shall
confine my remarks entirely to the direction of the wind as registered,
and not attempt on the present occasion to connect any barometric or
thermometric observations with these. As it would not be possible to
illustrate more than a few of these observations, I have selected those
only in which the wind has been tolerably steady and strong, as being the
best mode of giving a correct idea of the nature and value of these ob-
servations.

On the 17th of November, 1838, a steady wind set in at Ply-
mouth about 8 o'clock a.m., from the S. by E., and continued until
8 o'clock on the following evening, a period of thirty-six hours.
The steadiness of this current at Plymouth was very remarkable :
during the first part of the time there was almost a perfect calm in
Birmingham; however, by 10 o'clock in the evening, that is to say,
fourteen hours after the current from the S. by E. had set in at Ply-
mouth, a slight wind was felt at Birmingham from the north ; in three
hours more, that is, by 1 a.m. on the 18th of November, it became
E.N.E., and finally set in a strong gale from N.E. by N., which lasted
the remainder of the day. It is a singular fact, that as the gale in-
creased in force at Birmingham it declined at Plymouth ; this was
towards the middle of the day ; in the evening the contrary took
place. The rush of air from the S. by E. at Plymouth continuing for
such a length of time previous to any wind being felt at Birmingham,
clearly shows that this must have been the main current ; and it seems
highly probable that the atmosphere for some distance north and south
of this current was gradually affected, and eventually drawn into it.
The state of the wind on the next day (November 19th) very much
confirms this view of the subject : the current by that time became due
E. at Plymouth, and N.E. at Birmingham. On the 20th there was but
little wind at either place, and the directions then became the same in
both places. During a considerable portion of the time much rain fell,
about '16 of an inch in Birmingham, and 1*32 at Plymouth; the two
principal falls in Plymouth preceding those in Birmingham by about
four hours.

On March 28 a strong wind set in from the west at Plymouth,
which continued the whole day. At Birmingham the wind was S.S.W.
when this gale commenced ; but alter continuing in that direction
about twelve hours, it moved gradually round to the west, and finally
to the W.N.W. During the time of this change, the strength of
the wind at Plvmouth increased considerably, though it did not alter

1839. ' c

18 REPORT 1839.

in direction. A deflection in the wind, in the opposite direction to
what is now described, sometimes takes place, but not so frequently.
As to whether these deviations are in regular curves, and are segments
of large circles, or merely deflections in the course of the currents
caused by some peculiarity in the situation of the places, or whether
it be our insular position that modifies the currents, I cannot venture
an opinion. The course of the currents is, as might have been ex-
pected, much more steady at Plymouth than at Birmingham. Thus
on the 29th, 30th, and 31st of January last, the wind commenced at
due west, and veered at a perfectly even rate round to the north : while
in Birmingham the course of the current was exceedingly unsteady,
and veered round one half the compass, in Plymouth it only moved
one quarter. This, among many other instances which I could bring
forward, shows that great care should be taken in the selection of sta-
tions for making observations concerning the course of the main cur-
rents of the atmosphere, which ought to be our principal object in the
first instance ; for we must not hope, for a long time to come, to lay
down the minor fluctuations by which the greater ones are modified.

I shall conclude with a few remarks on the great storm of the 6th and
7th of January last (1839), that committed such dreadful ravages in this
country, and trace its probable course and action. In addition to the re-
cords obtained by the anemometer at this place and at Plymouth, I have
collected what information I could concerning the nature and extent of
this storm from many parts of the British Isles. A careful analysis of these
strongly leads me to the opinion that this was a small but violent rotatory
storm, moving forward at the rate of about thirty to thirty-five miles per
hour. The diameter of the rotating portion I am not prepared to give,
nor do I consider it at all certain that it could be ascertained, as it
seems likely that the revolutions were not in contact with the earth. The
tendency of this eddy, or violent whirling of the air, would, of course,
be to produce a vacuum in the centre. The air that forms the eddy
being constantly thrown off" in a slight degree spirally upwards, and
dispersed in the upper portion of the atmosphere, the effect of this
would be to produce a strong current upwards. Now, supposing
this large eddy to be perfectly stationary, there would be a rapid rush
of air towards it from all sides, which would be drawn up and
thrown off through this rotating circle, and dispersed with amazing
rapidity above : but as it is moving on with great velocity, the air that
is in the advance of the storm is not sensibly affected until the whirl is
close to it ; while in the rear the motion of the air is greatly increased ;
first, by the tendency of the air to rush into the great vortex of the storm ;
and, secondly, by the motion onward of the vortex itself. This vortex
or revolving column would increase in size upwards, so as somewhat to
resemble a funnel ; it would in fact be similar in its shape and action to
an immense water-spout ; whether it was vertical or not is entirely a
matter of conjecture, bat I should consider it probable that it would
incline in the direction that the storm was moving ; namely, to the
N.E., and that it was an upper current that carried it in that direction.
The greatest intensity of the storm in England was evidently across

TRANSACTIONS OF THE SECTIONS. 19

Lancashire and Yorkshire. I therefore conceive that the nucleus of the
hurricane passed in a N.E. direction over these two counties. Towards
the sides, however, a little current set in a S. and even slightly in a S.E.
direction, on the S. side of the vortex, and in a N.W. and westerly di-
rection on the N. side, as before stated ; but the main rush was behind.
The anemometer at Birmingham shows that we here first felt a fresh
S. wind with a slight bearing of E. in it, which very shortly became
more westerly, increasing considerably in violence, and it then moved
round to the S.W., and became quite a hurricane, and continued so,
very violent at first, but decreasing in strength during the remainder
of the day : at Plymouth it commenced as a S.W. and then very gra-
dually moved round a little more westward. It was by careful exami-
nation of the records of these two instruments that I arrived at the
view I ventured to take of this storm ; and the evidence that I have
collected from various parts of the country concerning it, strongly con-
firms me in the opinion I have taken of it. Many violent storms fol-
lowed in the wake of this extraordinary hurricane, but I have not
attempted to investigate these, as the main storm must have thrown
the atmosphere into so disturbed a state, that it would be very likely to
produce minor eddies, gusts, &c.

On the Temperature of the Earth in the deep Mines of Lancashire and
Cheshire. By Mr. Eaton Hodgkinson.

These experiments were made with thermometers belonging to the
Association, and in the prosecution of them the author has been very
greatly assisted by the proprietors of pits and others connected with
them, who have kindly undertaken to observe the results themselves —
thus saving the author the trouble, in some cases, of going more than
once into the mine. In the salt mines of Messrs. Worthington and
Firth, at Northwich, in Cheshire, latitude about 53° 15', a thermometer
placed in a bore-hole 3 feet deep in the rock, 112 yards below the
surface, indicated a temperature of 5P to 51^° Fahr., and varied little
or nothing between summer and winter. In the deep coal-mines of
Messrs. Leeses, Jones, and Booth, near Oldham, a thermometer, placed
in a bore-hole as before, 3294- yards below the surface, varied from 57°
to 58^° Fahr., from observations made for a whole year by Mr. J. Swain.
In the Hay dock colliery, 201 yards deep, about 18 miles west of Man-
chester, and differing from it but little in latitude, the temperature
varied considerably, both in the same hole and in different ones, but
approached to 58". The cause of these anomalies the author has not
discovered. The experiments were made for him by Mr. William
Fort. Other experiments are in progress. The latitude of Manchester
is 53° 30', and the mean temperature of the air there is 48° Fahr., from
Dr. Dalton's experiments.

20 REPORT— 1839.

On a New Calorimeter, hy which the heat disengaged in combustion
may be exactly measured, with some introductory Remarks upon the
Nature of different Coals. By Andrew Ure, M.D,

After some remarks on the quantity of sulphur in coal, and a table
of results obtained by analysis, Dr. Ure thus describes his Calorimeter
and its application. The apparatus which I employ consists of a large
copper bath capable of holding 100 gallons of water : it is traversed,
forwards and backwards, four times, in four different levels, by a zig-
zag horizontal flue, or flat pipe, nine inches broad, and one inch deep,
ending below in a round pipe, which passes through the bottom of the
copper bath, and receives there into it the top of a small black lead
furnace. The interior furnace, which contains the fuel, is surrounded,
at the distance of an inch, by another furnace, which case serves to
prevent the dissipation of heat into the atmosphere. A pipe, from a
pair of double-cylinder bellows, enters the ash-pit of the furnace at one
side, and supplies a steady current of air to keep up the combustion,
kindled at first by half an ounce of red-hot charcoal. So completely is
the heat which is disengaged by the burning fuel absorbed by the water
in the bath, that the air discharged at the top orifice has usually the
same temperature as the atmosphere. In the experiments made with
former water calorimeters, the combustion was maintained by the current
of a chimney, open at bottom, which carried off at top a quantity of
heat very difficult to estimate. My experiments have been directed
hitherto chiefly to a comparison of the heating powers of Welsh an-
thracite, Llangennech, and a few other coals. I have found, that the
anthracite, when burned in a peculiar way, with a certain small admix-
ture of other coals, evolves a quantity of heat at least 35 per cent, greater
than the Llangennech does, which latter is reckoned by many to be
the best fuel for the purposes of steam navigation. One half-pound of
anthracite, burned with my apparatus, heats 600 pounds of water 10°
Fahr., viz. from 62° to 72°, the temperature of the atmosphere being
66°; whereby no fallacy is occasioned either by the conducting
powers of the surrounding medium, or by a chimney current. We
thus see that one pound of anthracite will communicate, to at least
12,000 times its weight of water, an elevation of temperature of 1°, by
Fahrenheit's scale. For the sake of brevity, we may call this quantity,
or energy, 12,000 unities of heat. One pound of Llangennech, in the
same circumstances, will afford 9,000 unities : one pound of good char-
coal, after ordinary exposure to the air, affords 10,500: perfectly an-
hydrous charcoal would yield much more : one pound of Lambton's
Wall's-end coals affords 7,500 unities. It deserves to be remarked, that
a coal, which produces in its ignition much carburetted hydrogen and
water, does not afford so much heat as a coal equally rich in carbon,
but of a less hydrogenated nature, because, towards the production of
the carburetted hydrogen and water a great deal of latent or specific
heat is required : indeed, the evaporation of unburnt volatile matter
from ordinary flaming coals abstracts unprofitably a very large portion

TRANSACTIONS OF THE SECTIONS. 21

of their heat, which they would otherwise afford. Hence, those chemists
who, with M. Berthier and Mr. Richardson, estimate the calorific powers
of coals by the quantity of carbon which they contain, or the quantity
of oxygen which they consume, have arrived at very erroneous conclu-
sions. The amount of error may be detected by experiments on the
cokes of flaming coals. M. Berthier examines coals for their propor-
tion of carbon, by igniting a mixture of each, finely pulverized, with
litharge, in a crucible, and estimates 1 part of carbon for every 34 parts
of lead which is reduced. I have made many researches in this way
with both charcoal and anthracite, and have obtained very discordant
results. In one experiment, 10, grains of pulverized anthracite, from the
vale of Swansea, mixed with 500 grains of pure litharge, aff'orded 380
grains of metallic lead; in a second similar experiment, 10 grains of the
very same anthracite afforded 450 grains of lead ; in a third, 350 grains.
In one experiment with good ordinary charcoal, fresh calcined, 10
grains, mixed with 1,000 of litharge, afforded no less than 603 grains
of metal. The crucible was in each case covered and luted. My
future researches, which are intended to embrace every important va-
riety of fuel, natural and artificial, will be made with an apparatus
somewhat modified from that here described. Three furnaces will be
inclosed within each other, with a stratum of air or ground charcoal
between each, so as to prevent all loss of heat into the atmosphere, and
thereby to transfer the whole heat disengaged by combustion into a
large body of water, of a temperature so much below that of the at-
mosphere at the beginning of the experiment, as it shall be above it at
the conclusion.

On a method of JiUing a Barometer without the aid of an Air-pump,
and of obtaining an invariable level of the surface of the Mercury in
the Cistern. By Prof. Stevelly.

Prof. Stevelly said that it was very difficult to fill a barometer tube
so as to be quite free from air and moisture. Mr. Daniell, in his Me-
teorological Essays, proposed to fill the barometer under the exhausted
receiver of the air-pump, and actually had the barometer of the Royal
Society so filled by Mr. Newman, under his own superintendence ; but,
although an expert London working optician might be found capable of
executing successfully such a task, yet few in the country could hope
for such an advantage ; and, in fact, although he had attempted the
process at Belfast, he had never succeeded. After some consideration,
the following simple mode of using the Torricellian vacuum of the tube
itself, instead of the air-pump, in filling it, occurred to him. He heated
the mercury as hot as it could be handled, and filled the tube, in the com-
mon way, to within half an inch of the top ; then worked out, in the usual
way, all air-bubbles, as perfectly as possible ; filled up the tube to the
top, and inverted it in a cup of hot mercury, when of course it sub-
sided, in the upper part of the tube, to the barometric height ; he then
placed his finger on the mouth of the tube, under the mercury in the

22 REPORT — 1839.

cup, and lifted it out; and, still holding his finger tightly over the
mouth of the tube, laid it flat on a table, when the mercury in the tube
soon lay at the under side of the tube, leaving the upper part along the
length of the tube void. Upon then turning the tube slowly round,
still keeping the finger on its mouth, every speck of air was gathered
up. He then placed the tube in an upright position, with its mouth
upwards, still keeping the finger firmly on ; and, placing a funnel of
clean dry paper about the upper part, an assistant filled the funnel with
hot mercury, so as to cover the finger. Upon slowly withdrawing the
finger, the mercury went gently in, and displaced almost perfectly the
atmospheric air which had gathered into the void space. By renewing
the process which succeeded the previous washing of the air out of the
tube, once, or at most twice, a column of the most perfect brilliancy
was obtained. He had mentioned this simple method to Dr. Robinson,
of Armagh, who suggested that, to get rid of the damp and greasiness
of the finger, it would be better to cover it during the process with
clean and dry caoutchouc ; and this was found a decided advantage.

The method of procuring an invariable surface in the cistern was
equally simple. From the imperfection of the author's sight, it was an
object of much interest to him to have as few readings or adjustments
depending on sight as possible. He proposed, therefore, to divide the
cistern into two compartments, by a diaphragm of sheet iron or glass,
brought to a sharp edge at top. Into one of these compartments the
barometer tube dips ; in the other is placed a plunger of glass or cast
iron, which can be raised or lowered by a slow screw movement. To
prepare for an observation, the plunger is first screwed down, by which
it displaces the mercury in one compartment, and raises its surface in
the other above the edge of the diaphragm ; upon raising it slowly
again, the mercury drains ofi* to the level of the edge of the diaphragm,
thus, at every observation, reducing the surface to a fixed level.

A letter was received from Prof. A. D. Bache of Philadelphia, on
the subject of rain at different heights. It is expected that this and
other subjects will be treated of in the Report on the Meteorology of
the United States of America, which Mr. Bache has undertaken to
draw up for the Association.

Experiments to determine the Fluency or Viscidity of different Liquids
at the same Temperature, and of the same Liquids at different Tem^-
peratures. By Dr. Ure.

The author, referring to a memoir read to the Society of Civil Engi-
neers, states a new mode of experiment and gives the results as under.

Upon this occasion I put the liquid, either cold or heated to a certain
temperature, into a glass funnel, terminated at its beak with a glass
tube of uniform bore, about one eighth of an inch in diameter, and three
inches long. The funnel was supported in a chemical stand, and dis-

TRANSACTIONS OP THE SECTIONS. 23

charged its contents, on withdrawing a wooden pin from the beak, into
a glass goblet placed beneath, alongside of which a chronometer was
placed to indicate, in seconds, the time of efflux. The volume of liquid
used in each case was the same, — viz. 2,000 grain-measures, at 65° Fahr.
The times of efflux with liquids of the same specific gravity and bulk,
in the same vessel, vary with the viscidity of the liquids, and serve to
measure it. A correction ought to be introduced in estimating the
times of efflux of hot liquids, on account of the enlargement, by
expansion, of the bore of the glass tube ; but this, being a point of
little consequence in the practical application of this inquiry, has been
neglected.

2,000 grain-measures of water, at 60° Fahr., ran off in 14 sec.
68 13

164 12.

When the funnel and glass tube were faintly smeared with oil, though
perfectly pervious, and apparently clean, boiling hot water having been
run through them,

2,000 grain-measures of water, at 150° Fahr., ran offin24 sec.
142 23

94 24

56 25.

So great is the repulsive influence between oil and water, in retarding
the flow of the latter through a small orifice.

2,000 grain-measures of Fahr. Spec. grav. Sec.

Oil of turpentine 65^^

Pyroxylic spirit ,,

Alcohol „

Nitric acid „

Sulphuric acid ,,

Ditto 262

Saturated solution of sea salt 65

Sperm oil ,,

Fine rape-seed oil ,,

Fine pale seal oil ,,

Fine South Sea whale oil ,,

Sperm oil 254

Rape-seed oil 254

South Sea oil 250

The rape-seed oil is so viscid, as to burn with difficulty in lamps of the
ordinary construction, but in the hot oil lamp of Parker it affords a
very vivid light. In my former apparatus, the difference of level be-
tween the two legs of the siphon, which constituted the effective pres-
sure of efflux, was only half an inch, whereby 2,000 grain-measures of
sperm oil, at 64°, took no less than 2,700 seconds to run off, while that
volume of oil of turpentine ran off in 95 seconds. It would therefore
appear that the fluency of a viscid oil diminishes in a very rapid ratio
with the diminution of pressure. Hence, an oil will burn well in a
mechanical lamp, where it is raised to the level of the bottom of the

' 0-874 ...

.... 14

0-830 ...

.... 14i

0-830 ...

.... 16

1-340 ...

.... 131

1-840 ...

.... 21

... 15

1-200 ...

... 13

0-890 ...

... 4.5i

0-920 ...

...100

0-925 ...

.... 66

0920 ...

.... 66

.... 15

... 17

.... 17

24 REPORT — 1839.

flame by pump work, which will afford a very indifferent light in one
of the French Annular or Sinumbral lamps, where the supply is given
by a very slight pressure.

Notice of a comparative Pendulum. By W. J. Frodsham, F.R.S.
The principle of this pendulum is the same as that which was pro-
posed some years ago by Mr. Reid of Woolwich, but the construction
IS different. Over the steel rod of a common pendulum Mr. Frodsham
slips a zinc tube, which rests on the adjusting screw at the loAver end
of the rod, the bob being fastened at the centre by two connecting rods
of steel to the tube at the point where the expansion of the tube is the
same as that of the rod. By making the zinc tube a little too short,
and applying small rings cut from the same tube, as correcting pieces,
until the proper length is found, the evils of the irregularity of expan-
sion of different specimens of the same metals are overcome. The
author describes the means whereby he secures access for the air to
the zinc tube where it passes through the bob, and to its inner surface
surrounding the steel rod.

Mr. Frodsham also describes improvements in the mode of suspend-
ing the pendulum, particularly the application of a brass tube, called
an ' isochronal piece,' which slides on the rod, and at its upper part is
made to embrace the suspending spring, the acting part of which is
thus made variable in length without affecting the compensation of the
pendulum. When the suspending spring is in a state of rest and in
Its natural and unconstrained position, the isochronal piece is made to
embrace and unite it firmly to the rod, by two screws at the upper
end, thereby preventing any strain or warp to which the spring is
subject by the method usually employed. To any given weight of the
bob of the pendulum, it appears that some particular length and
strength of the suspending spring is better adapted than any other to
produce isochronism in the pendulum, and the use of the 'isochronal
piece,' in producing in any spring the nearest approach to this condi-
tion, is obvious.

On the Motion of Points or Atoms subject to any law of force.
By J. K. Smythies.

The method of investigating the motions of points proposed is, to
find equations necessarily existing between their distances ; thence to
deduce others involving any required combination of the distances, and
their differentials of any orders necessarily true for all moving systems;
and then, combining those equations, which assign a particular law of
motion, with those which are true for all motions, to eliminate the dif-
ferentials of all or any required number of orders by a simple mode of
elimination.

If there are any number of points (w) in space, the following equa-
tion subsists between their distances, where 12 or 21 denotes the

TRANSACTIONS OF THE SECTIONS.

distance between the 1st and 2nd points, &c. ; and a term with S pre-
fixed denotes the sum of all the terms of the same type, terms being of
the same type when deducible from each other by substituting one
figure for another, or by any number of successive substitutions.

2 2 22 _*_* _2 2 2 2

2 (w-4)S 12.23.34.41 -(w-4)S12.34 + 4 S 12 .23.31 .45

\ \

2_ 2 4

+ 2 S 12.23.45

2 _ 2 2 2

2S 12.23.34.45 = 0.

The subscribed diagram shows how the lines are connected in each type.

If for each line we substitute its differential of the mth order, the
resulting equation is true : and generally, if we substitute for each
line the line increased by the sum of its differentials of every order up
to the mth, and separate all the terms involving products of the same
given dimensions for- every order of differentials, their sum equals zero.
Representing a function of the distances and their differentials symme-
trical for thelst and 2nd points, and also for the rest, thus F (12 34...^^)
all these equations can be put under the form Zd"^ 12.F(12 34...?2) =0.

These equations will be sufficient when the law^ of motion of the sy-
stem is assigned by equations involving only the distances and their dif-
ferentials; but when it involves the absolute velocities of the points along
their own paths, we must find general equations between the distances,
the relative velocities of the points to or from each other represented
by the first differentials of the distances, and their absolute velocities
along their own paths. For this purpose divide 2 n points into two
equal groups, denoting two successive simultaneous positions of the n
points. Draw right lines from each point to every other in its own
group, and to one in the other. An equation rnay be found between
these n- lines thus drawn between the 2 n points. When the n lines
connecting the two groups are indefinitely diminished, their limiting
values denote the absolute velocities of the points ; and the limiting
differences of the distances of the same two bodies, in the two groups,
denote their relative velocities, or the first differentials of the distances.
Equations involving higher orders of differentials may be deduced from
this as from the preceding.

26 REPORT — 1839.

By combining these equations with those which assign the law of
motion, it is always possible to eliminate all the differentials if the
number of points (n) be taken great enough ; and when we assume
(as in all physical applications to general laws of force we must,) that
the distance between every two points is the same function of the
masses, positions and motions of the rest, it may be effected in a simple
manner.

On certain Results, regarding the minimum thickness of the Crust of the
Globe, which might be consistent with the observed phcenomena of
Precession and Nutation, assuming the earth to have been originally
fluid. By William Hopkins, M.A., F.R.S., ^c.

The mathematical investigation is intended to appear in the Trans-
actions of the Royal Society.

Notice of certain Analytic Theorems. By Charles Blackburn, M.A.

Remarks on Dr. Wollaston's argument respecting the infinite Divisibility
of Matter, drawn from the finite Fjxtent of the Atmosphere. By the
Rev. Wm. Whewell, F.R.S.

He observed, that Dr. Wollaston had proceeded on this supposition :
That if the extent of the earth's atmosphere be finite, air must consist of
indivisible atoms ; since, as Dr. Wollaston assumed, the only way in which
we can conceive an upper surface of the atmosphere is, by conceiving an
upper stratum of atoms, the weight of which, acting downwards, is ba-
lanced by the repulsive force of the inferior strata acting upwards. Mr.
Whewell maintained, that such a mode of conception was altogether
arbitrary, and the argument founded upon it quite baseless ; for if we
investigate the relation between the height of any point in the atmo-
sphere, and the density of the air at that point, upon the supposition
that the compressing force is as the nth. power of the density, we find
that the density vanishes at a finite height whenever n is greater than
unity. Therefore, though the atmosphere do not consist of indivisible
particles, it will still have a finite surface. In fact, the finite surface of
the atmosphere no more proves the atomic constitution of air, than the
finite surface of water, in a vessel, proves the atomic constitution of
water. But it will still be asked, liow then is the highest stratum of
air supported ? To which the answer is, that there is no highest stra-
tum of definite thickness. Supposing the atmosphere finite, every
upper stratum of air bounded by the upper surface of the atmosphere,
has the upper part of that stratum supported by the lower ; and how-
ever thin the stratum be, it has still an upper and a lower part which
have this relation to each other. The question. What supports the
uppermost stratum of the atmosphere ? is of the same kind as the
question formerly discussed by writers on mechanics, What is the
velocity with which a body begins to fall ?

TRANSACTIONS OF THE SECTIONS. 27

Account of a recent successful Experiment to determine, hy means of
Chronometers, the difference of Longitude between Greenwich and
Neio York. By E. J. Dent.

The rapid transmission of chronometers now practicable by means
of steam-vessels from one meridian to another, offers great facilities for
the determination of the differences of longitude. This led me (said
Mr. Dent) to embark four chronometers on board the British Queen
steam-vessel, on her first voyage from England to America. Captain
Roberts, the commander of the vessel, kindly undertook the charge of
them, and (through the interest of Messrs. E. and G. W. Blunt, of New-
York), Jesse Hoyt, Esq., the collector of customs at that port, gave a free
permit, as well as every other facility, for landing them. They were then
compared daily with two astronomical clocks at the observatory at
Brooklyn, 4,700 feet, or 4*09 sec, east of the City Hall, in New York.
The errors of these clocks were determined by transit-observations on
the days of arrival and departure. The errors of the clock with which
the chronometers were compai'ed at Greenwich immediately before the
embarkation on board the British Queen, and also immediately after
their landing at Greenwich from that vessel on their return, were de-
termined by means of several series of zenith-distances of stars on both
sides of the meridian, and also of the sun, taken with a sixteen-inch
altitude and azimuth instrument at the Royal Naval Schools, Green-
wich, by the Rev. George Fisher. The stone pedestal, on which this
instrument was placed, is, by actual measurement, 560 feet, or 0^*6 west
of the transit-instrument at the Royal Observatory, which quantity is,
of course, applied to determine the Greenwich error. In determining
the difference of longitude in the present case, I use the methods which
I employed, first, in my journey for the same object between Green-
wich and Paris, and subsequently, in the other experiments which I
have made to determine the difference of longitude between Greenwich
and Oxford, Dublin, Armagh, Edinburgh, Cambridge, &c. The first
method is by means of the travelling rate, the second is by the station-
ary rate^. The "travelling rate" is the mean rate during the voyage,
obtained by dividing the difference between the previous and subse-
quent errors at Greenwich, by the number of days absent. The " sta-
tionary rate" is a mean of the rates determined, 1st, at Greenwich,
before the chronometers were embarked ; 2nd, at Brooklyn, after their
disembarkation there ; and 3rd, at Greenwich, on their return, after
their landing. The first method is, no doubt, the more unexceptionable
of the two ; it involves, indeed, the supposition of the outward-bound
rates being the same as the homeward-bound ones ; yet as errors, arising
from the magnetic action of the iron in the vessel upon the chrono-
meters, or other causes, would, in all probability, be in excess and
defect to the same amount, we might therefore reasonably expect a
compensation of errors to occur, or nearly so. It is very remarkable,
that on board the steam-vessel in all the chronometers, the mean " tra-

* These have been sometimes called the "shore rates" and the " ship rates."

28 REPORT— 1839.

veiling rate'' differs from the mean '■^stationary rate" in the same way,
or the losing rates were increased, and the gaining ones diminished.
Whether, however, we use the travelling rate or the stationary rate for
the determination of the difference of longitude of the two places, we
we obtain results extremely near to each other, provided we take the
means between the outward- and the homeward-bound determinations.
This was shown by calculations submitted to the Section. Taking the
first result, or that given by the travelling rate, as the true difference
of longitude between the Observatories of Brooklyn and Greenwich,
and applying the quantity, 4'09 sec. for the difference of meridians be-
tween the Observatory of Brooklyn and the City Hall, in New York,
we have for the difference of longitude between the latter place and
Greenwich 4^^ 56^ 7^'08 west. The longitude of NewYork from Paris,
as given in the Connaissance des Tems, by M. Daussy, is 5^ 5™ 22*'0 :
if from this be deducted 9"" 2P'28, the difference of longitude between
Greenwich and Paris, as determined by the chronometrical experiments
made by me between those two places in 1 837, we shall have 4*^ 56^
0^.72 as the difference of longitude, according to that observer, between
Greenwich and New York.

Comparison of Results.

First, by the chronometers, the longitude of New York is h. m. s.

west from Greenwich 4 5Q 7'08

Second, by M. Daussy, as given in the Connaissance des

Tems 4 56 0-72

Difference 6-36

This difference is little more than one half of a mile in longitude ;
and the smailness of it proves that this, {the first result by the transit
of chronometers from England to America,) removes the apprehensions
which have been suggested that chronometers may not go well in
steam-vessels.

Note, by Mr. Dent, accompanying a Table of the Hate of the Transit-
Clock in the JRadclyff Observatory, Oxford, was then read.

In 1S38 a transit-clock was made by Messrs. Arnold and Dent for the
Radclyff Observatory, Oxford, to which, by the special desire of the late
Professor Rigaud, was attached the improved mercurial pendulum with
its cistern of cast iron, &c. In the statement now submitted of the going
of this clock will be found, said Mr. Dent, a mean daily rate, which,
when corrected for an intentional over-compensation, has been rarely
equalled ; the amount of the correction for this over-compensation is,
I think for many reasons, a subject for experiment alone : I conceive
it cannot be calculated but with extreme difficulty — 1st, because the
centre of oscillation must be disturbed, and then an additional correc-
tion becomes necessary, in consequence of the alteration in the pendu-
lum-rod to bring it to time ; 2nd, because some quantity is due to the

TRANSACTIONS OF THE SECTIONS.

change of elasticity produced by extremes of temperature in the sus-
pension-spring ; and 3rd, because another quantity is due to that effect
of extreme cold which is indicated by a decrease in the vibration-arc
of the pendulum. In the present case, the reduction of compensation
required is so small, that until some cause for stopping the clock occurs,
Professor Johnson is not anxious that the compensation shall be at-
tempted.

The following is the monthly abstract of the mean daily rate of the
transit-clock, as observed by the late Savilian Professor of Astronomy :

Mean Daily Rate,
sec.

1838, October -0-136 . .

„ November — 0'51 1 . .

„ December — 0'987 . .

1839, January —0-887 . .

„ February —0*544 . .

„ March —0-414 . .

„ April -0-060 . .

„ May -1-0-016 . .

„ June +0*222..

„ July -1-0-375 ..

„ August -f-0*223 ..

Therm.

50*14
44-18
41-47
38*45
42-29
41-18
55*57
55-38
62-57
65*00
64-53

On Natural Perspective. By Mr. Parsey.

On an analogy between the atomic weights of certain Gases and the ex-
pansions of the primitive colours of the Solar Spectrum. By Lieut.
Morrison, R.N.

CHEMISTRY.

On the Theory of the Voltaic Circle. By Prof. Graham.

Professor Graham explained the views now received of the propa-
gation of electrical induction through the fluid and solid elements of
the voltaic circle, by the formation of chains of polar molecules, each
of which has a positive and negative side, and in which no circulation
of the electricities is supposed, but merely their displacement and se-
paration from each other in each polar molecule. These electricities

30 REPORT— 1839.

in the polar molecule of hydrochloric acid, for instance, are displaced,
when the acid acts as an exciting fluid, and the positive electricity is
located in the chlorine atom, and the negative electricity in the hydro-
gen atom. The electricities are, at the same time, made the deposit-
ories of the chemical affinities of the chlorine and hydrogen respec-
tively. Mr. Graham proposed to modify this hypothesis so far as to
abandon the idea of electricities being actually possessed by these
bodies, and to refer the phenomena at once to the proper chemical affi-
nities of the bodies. He assigned similarly polar molecules to the
exciting fluid and metals ; and taking hydrochloric acid as a type of
exciting fluids, he gave to each molecule a pole, having an affinity re-
sembling that of chlorine, or chlorous affinity, instead of negative elec-
tricity, and another pole, having an affinity resembling that of zinc or
hydrogen, or zincous affinity, instead of positive electricity. When zinc
and acid are in contact, the polar state of a single chain of molecules
might be represented as in the figure.

SS2SS®@©®©

The particle of acid B, next the zinc, has its chlorine atom in con-
tact with the metal and its hydrogen atom distant from it, marked re-
spectively cl and z in the figure. Part of the affinity of cl being en •
gaged by the zinc, the hydrogen is so far received from that affinity,
and thus attracts the cl of C. Thus, by a sort of induction, the z of B
causes the cl of C to be chlorous, or the molecule of acid C to become
polar, and that again the molecule D. In the zinc, (the molecule being
supposed to contain two chemical atoms,) while the external atom of A
becomes zincous, from its contact with the acid, the other atom be-
comes chlorous ; so that these atoms of this molecule may be marked
cl and z, and so also the molecules E and I of the zinc, which become
polar by induction.

In another diagram Professor Graham showed how this chemico-polar
condition is propagated round a voltaic circle. The molecules of the
zinc and acid being polar by contact, which is sufficient to develop
their affinities, an induction one way through the zinc, and in the op-
posite direction through the acid, conspire to produce the same polar
condition in the molecules. The result is, that the molecule 2; of A is
zincous both primarily and by induction, and its affinity for the atom
cl of B greatly increased ; and, consequently, combination can take
place between these atoms when the circuit is completed, but not
otherwise.

If the connecting wire be broken, and a decomposable liquid, such
as hydriodic acid, be interposed between the extremities, a chain of polar
molecules comes also to be established in that liquid, the iodine (which
is the analogue of chlorine) being the seat of the chlorous affinity, and
the hydrogen the seat of the zincous affinity. The extremity of the
wire connected with the copper plate is zincous, or has zincous affinity,

TRANSACTIONS OF THE SECTIONS. 31

and consequently attracts the iodine which appears there, when decom-
position occurs. The extremity of the wire connected with the copper
plate is chlorous, or has the affinity of chlorine ; and consequently, the
hydrogen of the hydriodic acid is eliminated there when decomposition
occurs. These poles in the decomposing cell of the voltaic circle have,
from their importance, always received peculiar appellations, which,
with two other terms, Mr. Graham changes as follows :

Chlorous = Negative.

Zincous = Positive.

Chloroid =The negative pole, the cathode, the platinode.

Zincoid =The positive pole, the anode, the zincode.

Mr. Graham afterwards endeavoured to show, that electrolytes were
bodies which, like hydrochloric acid, possessed a salt radical and basyle
element, which might be the seat of the chlorous and zincous affinities,
and which might, indeed, be called the chlorous and zincous elements
of the electrolyte ; so that the same view was applicable to electrolytes
in general*.

Notice of new Electro-chemical Researches. By Professor Schonbein,
{of Basle).

" The discovery of the chemical power of the voltaic pile made in the
beginning of our century by British philosophers, could not fail draw-
ing the attention of the scientific world upon the relations which exist
between chemical and electrical phaenomena. Indeed, only a few years
after this important fact had been acertained, your illustrious country-
man. Sir Humphry Davy, as well as the celebrated Swedish philosopher
Berzelius, did not hesitate to establish the theory which has since been
generally adopted, and which is founded upon the principle that che-
mical and electrical forces are essentially the same.

" Having almost exclusively occupied myself these last six years with
researches bearing upon the subject in question, and having obtained
from them some results which seem to be altogether irreconcileable
with the very first principles of the electro-chemical theory, I enter-
tain the hopes, that by making known the details of the investigations
alluded to, I shall render some service to science."

From a review of the consequences flowing from the ordinary elec-
tro-chemical theory, M. Schonbein observes :

" It follows from the doctrines laid down by Davy and Berzelius, that
any metal put by any means into the negatively electrical state, has its
affinity for oxygen either diminished or altogether destroyed, so as to
cease to be an oxidable metal under ordinary circumstances. Now let
us see how far facts agree with the principles of the electro-chemical
theory.

* Mr. Graham has since developed his views more fully in the Third Part of his
Elements of Chemistry, pp. 197 — 241.

32 REPORT — 1839.

First fact.

A piece of iron was voltaically associated with a piece of zinc, and
each of these metals put into a separate vessel filled with common water.
The vessels did not communicate with each other. Only a few hours
after the immersion of the iron had been effected, light flakes of oxide
of iron made their appearance round the metal ; and, after a couple of
days, the latter was corroded to a considerable degree. The same re-
sult was obtained when I plunged the iron piece into water, and made
the zinc rise above the level of the fluid, so as to prevent the latter metal
from being in the least contact with water. According to the judge-
ment of my eye, a piece of iron, being immersed into water without
any voltaic association, was no more corroded than that metal appeared
to be under the circumstances just stated.

Second fact.

Two pieces of iron wire were made, one of them the positive, the
other the negative pole of a voltaic pile, which consisted of ten pairs
of copper and zinc, and was charged with water holding 5 per cent, of
common salt dissolved. Each of the polar wires was put into a sepa-
rate vessel filled with common water, so as to leave the pile unclosed.
Under these circumstances, both wires were equally attacked and cor-
roded, in the same manner as if a single piece of iron had been put
into water ; for, after the lapse of a couple of hours, the polar wires
were seen to be surrounded by light flakes of oxide of iron.

Third fact.

A piece of iron being voltaically associated with zinc, was exposed
to the action of the atmosphere. Having left this voltaic pair for some
time to itself, the iron part of it appeared to be covered with a thin
layer of rust ; and on comparing it with a piece of iron which had also
been placed within the atmosphere during the same space of time, I
could not see any notable difference between the states of the surfaces
of both pieces.

Fourth fact.

A piece of iron wire was connected with each of the poles of a vol-
taic pile, without making the wires touch each other. Being exposed
to the action of the atmosphere, under these circumstances, both polar
wires appeared, after some time, equally aff'ected by rust, and just so
as another piece of iron did which was not connected with a pile.

Fifth fact.

A piece of iron, being voltaically associated with zinc, was put into
common water, so that both metals took up their place within the same
vessel. Though I have kept that voltaic pair within water these last
twelve months, the iron part of it does not appear to be in the least
oxidized, its surface being perfectly brilliant.

TRANSACTIONS OF THE SECTIONS. 33

Sixth fact.

A piece of iron wire was connected with each of the poles of a pile,
and each of these pieces made to plunge into a separate vessel filled
with common water, both vessels being connected by the means of a
piece of platina. That part of the negative polar wire which was im-
mersed in water did not rust at all, as long as there was a current
passing through the arrangement.

Seventh fact.

Copper being intimately associated with zinc^ and brought into an
aqueous solution of chloride of sodium in such a manner that each of
the metals did plunge into a separate vessel, was soon chemically
affected; provided, however, both vessels were not communicating
with each other.

Eighth fact.

The same experiment was made as in the preceding case, with the
difference however that both metals did plunge into the same vessel.
Under these circumstances the copper piece was not in the least cor-
roded by the salt water, whatever was the length of time during which
I kept the metals immersed.

Ninth fact.

A piece of copper was connected with each of the poles of a vol-
taic pile, and put into a vessel holding an aqueous solution of common
salt. Both pieces were attacked by the fluid, just in the same way as
if they had not been attached to a voltaic arrangement, provided both
vessels did not communicate with each other.

Tenth fact.

The experiment was made as in the preceding case, with the dif-
ference only that both vessels were caused to communicate with each
other by the means of a piece of platina. The positive polar wire
quickly underwent oxidation, whilst the negative one remained un-
touched. If an aqueous solution of common salt was made use of as
the exciting fluid in the pile, and the latter left unclosed, the copper
pieces of the voltaic pairs rather readily entered into oxidation, whilst
they were not at all chemically affected when the pile was closed.

Eleventh fact.

A piece either of copper or of iron was connected with each of the
poles of a pile ; two tumblers were filled, partly with mercury, partly
with water, or with a solution of common salt, and both vessels made
to communicate with each other by a piece of platina, so as to make
each extremity of the latter enter into the mercury of either vessel.
Things having been arranged in the manner described, the polar wires
were introduced, each of them into one of the tumblers, so that the
free end of each wire was made to plunge into the mcrcurv. Under

1839. n

34 REPORT — 1839.

these circumstances both polar wires appeared to be equally affected
by the non-metallic fluids, i. e. so as they would have been if not con-
nected with any voltaic arrangement."

On the basis of these facts, corroborated by various collateral phae-
nomena, M. Schonbein ventures to assert, that in the common case,
when copper or iron, acting as a negative electrode, in an aqueous fluid
holding oxygen dissolved, is not chemically affected by the latter ele-
ment, voltaic action has directly nothing to do with the protection of the
iron or copper. He then proceeds to explain his theory of the galvani-
zation of metals, by applying it to this particular case, and finally
affirms the following propositions :

1. Neither common nor voltaic electricity is capable of changing the
chemical bearings of any body ; and the principles of the electro-che-
mical theory, as laid down by Davy and Berzelius, are fallacious.

2. The change which certain metallic bodies, being placed under the
influence of a current, seem to undergo with regard to their chemical
relations, is due to some substance or other being produced and de-
posited upon those bodies by the agency of current electricity.

3. The condition, sine qua non, for eflicaciously protecting readily
oxidable metals against the action of free oxygen being dissolved in
fluids, is to arrange a closed voltaic circle, being made up on one side
of the metal to be protected, and another metallic body more readily
oxidable than the former, and on the other side of an electrolyte con-
taining hydrogen ; for instance water.

Researches on the Electrical Currents on Metalliferous Veins made in
the mine Himmelsfurst, near Freyherg. By Prof. Reich.

Since Mr. Fox first discovered the fact in copper mines in Cornwall,
it has been known, that an electrical current is indicated by Schweig-
ger's multiplier, when two points, where ore presents itself, are con-
nected by a metallic wire, whether these be in the same or different
veins. Mr. Fox repeated the experiments in lead veins, with similar
results. On the other hand, Von Strombeck (Karsten's Arckiv, vi. p.
431) could find no trace of such electrical currents in lead and copper
veins on the right bank of the Rhine ; again, Henwood repeated the
experiments in CornwaU, and confirmed the results of Fox. Prof.
Reich has made similar experiments in the mine Himmelsfurst, which
lead to very decisive fundamental results. The method of experiment
was in the main that of Fox. When the two points to be connected
were determined, a fresh surface was first worked on each, and on this
a disc of copper 6 inches long, 3 inches wide, was kept firmly pressed
by a piece of wood. An uncovered end of a copper wire, spun over
with silk, was kept pressed to the copper plate by means of a clamp.
The one wire was always short; the other, about 180 metres long, was
rolled on a reel. This latter was retained in all the experiments, the
current having thus the same length of wire to pass, so that its influence
on the amount of deviation of the needle was constant. The long wire

TRANSACTIONS OF THE SECTIONS. 35

was let out till it reached to the second point of contact, near which
the multiplier was placed, and the two ends of the fine wires connected
with it. The multiplier, with double needle, and very sensible, be-
longed to a thermo-electric apparatus of Melloni, made by Oertling of
Berlin. In order in some measure to judge of its delicacy, it may be
mentioned, that a current, from a pair of zinc and copper plates of
only one inch square, placed in water very weakly acidulated, drove
the needle up to the button, placed at 90°, to prevent further deviation ;
that an iron wire connected with two brass wires, placed in the multi-
plier, by the mere heating with the hand of the point of contact, pro-
duced a deviation of from 10° to 20°, according to the temperature
communicated. The following results were obtained: — 1. Two ore
points, separated by a non-metalliferous mass, or between which there
occurs a cross vein, or a space where the vein is worked out, give rise
to an electric current in a metallic wire connecting them. This law
was determined by seventeen experiments with every variety in them,
so as to obviate all objections. 2. Two ore points, in uninterrupted
metallic connection with one another, induce no electrical current
through a wire connecting them. 3. If only one disc be connected
with an ore point, and the other with the timbering, or be held in the
hand, there is no effect produced on the multiplier. This result was
confirmed several times. 4. If an ore point be connected with masses
of ore already won, a current sometimes manifests itself, and sometimes
there is none. 5. When an ore point is connected with non-metallife-
rous rock, frequently no current takes place ; frequently, however, a
current, always feeble, occurs in the connecting wire. This result does
not agree with that of Fox and Hen wood, who never detected a cur-
rent. Professor Reich performed the experiment eighteen times.

With respect to the cause of the electrical currents, observed in
metalliferous veins, three difi^erent opinions have been broached.
They have been ascribed, 1, to general electric currents at the earth's
surface, produced either entirely or in part by the earth's magnetism :
2, to hydro-electric, and 3, to thermo-electric actions of the various
metallic components of the vein. The first hypothesis, according to
Reich, is refuted by the independence of the direction of the currents
on their position relatively to the earth's axis. Thermo-magnetism he
holds to be incapable of producing such strong currents, as the strong-
est currents are observed exactly where the two points were separated
by a non-metallic conductor; and he concludes that there remains
only the hydro-electric action of the metallic components of the vein
to account for the phenomena. In respect to the extent of the devia-
tion of the multiplier, it is to be borne in mind, that there can be no
immediate conclusion drawn from this as to the electric difference of
the substances coming into play ; for it depends on the resistance to
conduction in the entire circuit, which again depends on the dimensions
and nature of the intervening rock, as also on the more or less perfect
contact between the copper disc and the ore, and between the disc
and the wire.

36 REPORT— 1839.

Some Observations on the preparations of Barium and Strontium.
By Dr. Hare, in a Letter to J. F. W. Johnston, Esq.

" Philadelphia, July 4, 1839.

" By means of the alternate action of two deflagrators, each of 100
pairs, containing more than 100 square inches of zinc surface, assisted
by refrigeration*, I procured amalgams of barium, strontium, and cal-
cium from their chloride ; and by distillation in an iron crucible, in-
cluded in an air-tight alembic of the same metal, have extricated the
metals above mentioned from their mercurial solvent.

" They are so oxidizable, that in order to see their brilliant white
metallic colour the eye must follow close upon the track of the file or
the burnisher. Almost as soon as a fresh surface is exposed, it assumes
a straw colour, like that of iron in the first stage of oxidizement, and
is soon completely obscured by the generated oxide. In this way
barium and strontium are more ready to oxidize than calcium, although
the amalgam of this last-mentioned metal changes much more rapidly
in the air. The amalgams of the former metals are more like that of
potassium.

" Either metal is rapidly oxidized in water, or in any liquid contain-
ing it, and gives afterwards, with tests, the appropriate indication of
its presence. They all sink in sulphuric acid. They are all brittle,
and fixed, and for fusion require a good red heat.

" Of several kinds of naphtha in my possession, only one, which I
have distilled from a residue of the distillation of potassiumf, does not
act upon the metals above mentioned. After being for some time in
naphtha, their effervescence with water is much less active. Under
such circumstances they re-act, at first more vivaciously with hydric
ether than with water or chlorohydric acid, because the ether removes
a resinous coating derived from the naphtha."

On a small Voltaic Battery of extraordinary energy.
By W. R. Grove, Esq., M.A.
The author, referring to a communication in the Philosophical Ma-
gazine for February 1839, described the preliminary investigations
which finally conducted him to the construction of a new battery of
unusual power, though of very small dimensions. On the 15th of
April, 1839, M. Becquerel presented to the French Academy a small
battery constructed by the author, consisting of seven liqueur glasses
amalgamated, containing the bowls of common tobacco-pipes, the

* The metals were extricated from saturated solutions of their chlorides. The
chemical affinity between the radicals and the oxygen or chlorine in the solution being
the opponent of the voltaic action, and this affinity being exalted by heat while the
conducting power, and of course susceptibility of decomposition is lessened by the
same cause, render resort to a freezing mixture expedient.

t I mean the residue of the receiver, which, agreeably to my process, is an iron
tube. See the forthcoming volume of the American Philosophical Society.

TllANSACTIONS OF THE SECTIONS. 37

metals of zinc and platinum, and the electrolytes concentrated nitric,
and diluted muriatic sulphuric acids. This little apparatus produced
effects of decomposition equal to the most powerful batteries of the old
construction. (^Comptes rendus, 15 April, and Phil. Mag., May 1839.)
In his endeavours to render a construction on this principle practically
useful, the author found it economical and advantageous to employ on
the platinum side a mixture of concentrated nitric and dilute sulphuric
acids as an electrolyte. He also recommends parallelopipedal instead
of cylindrical vessels.

" The hastily-constructed battery, which accompanies the paper, con-
sists of an outer case of wood, height 5\ inches, breadth 5, width 3, (it
should be of glazed earthenware, similar to the Wollaston troughs,)
separated into four compartments by glass divisions ; into these com-
partments are placed four flat porous vessels, the interior dimensions of
which are 5"2^ and y^gths of an inch, the thickness of the 'parois' ^th
of an inch ; they contain each three measured ounces. The metals (four
pair) expose each a surface of 16 square inches, and the battery gives,
by decomposition of acidulated water, 9 cubic inches of mixed gases per
minute: charcoal points burn brilliantly, and it heats 6 inches of plati-
num wire, ^^gth of an inch diameter ; its effect upon the magnet, when
arranged as a single pair, is proportionately energetic ; it is constant
for about an hour without any fresh supply of acids. The porous
vessels are identical in their constitution with the common tobacco-
pipe.

" As far as my experiments go, its power with reference to Mr.
Daniell's battery is, ' ccBteris paribus,' as 16 to 1 ; but the relative pro-
portions vary somewhat with the series. The cost of the whole appa-
ratus is £2 2s.

" During the operation of this battery the nitric acid, by losing suc-
cessive portions of oxygen, assumes first a yellow, then a green, then a
blue colour, and, lastly, becomes perfectly aqueous ; hydrogen is now
evolved from the platina, the energy lowers, and the action becomes
inconstant. It is worthy of remark, as an argument for the secondary
nature of metallic precipitation by voltaic electricity, that the oxidated
or dissolved zinc remains entirely (or at least by far the greater por-
tion) on the zinc side of the diaphragm, the hydrogen alone appears to
be transferred ; and yet the reversal of affinities which the theory of
reduction by nascent hydrogen supposes, is an enigma difficult of solu-
tion.

" I have invariably observed in this battery a current of endosmose
from the zinc to the platinum, or with the ciirrent of positive electricity.

" The rationale of the action of this combination, according to the
chemical theory of galvanism, appears to be as follows : In the com-
mon zinc and copper combination, the resulting power is as the affi-
nity of the anion of the electrolyte for zinc minus its affinity for
copper ; in the constant battery it is as the affinity of the anion for
zinc, plus that of oxygen for hydrogen, minus that of oxygen for
copper. In the combination in question the resulting power is as
the affinity of the anion for zinc, plus that of oxygen for hydrogen,

38 REPORT — 1839.

minus that of oxygen for azote*; nitric acid being much more readily
decomposed than sulphate of copper, resistance is lessened, and the
power increased ; and no hydrogen being evolved from the negative
metal, there is no precipitation upon it, and consequently no counter-
action.

" I need scarcely add a word as to the importance of improvements
of this description in the voltaic battery : this valuable instrument of
chemical research is thus made portable, and by increased power in
diminished space, its adaptation to mechanical, and especially to loco-
motive purposes, becomes more feasible."

Notices of Experiments on the deposition of Metals by Voltaic Action.
By Thomas Spencer, Esq. {Liverpool.)

Among other experiments made by the author to ascertain the truth
of an opinion he had been previously induced to entertain, namely,
that if two fluids of different densities were placed as much as possible
in mechanical contiguity, that is, without the fluids being suffered to
intermingle, an electro-chemical current would be eliminated by the
disturbance of the electrical equilibrium, the following was described :

He took a very tall tubular vessel and half-filled it with a solution
of nitrate of silver ; he then added distilled water in the most careful
manner with a pipette, allowing the drops to run down the side of
the vessel until he had nearly filled it. By proceeding thus, he was
enabled to keep the fluids from intermingling, their density being
different. When thus filled, a narrow slip of silver was inserted, long
enough to go through both strata of the fluid. The whole was placed
in a dark situation, and suffered to remain for a few hours, when evi-
dent marks of voltaic action began to manifest themselves. In the
course of a few days beautiful metallic crystals had formed on that por-
tion of the silver that was immersed in the solution of the nitrate ; that
part of the slip situated where the two fluids met, was left to about one
eighth of an inch untouched, while that end placed in the acidulated
water became oxidized in the inverse ratio of the deposition on the
opposite end.

A series of slips of different metals, including zinc, were subjected
to similar treatment in their respective solutions, and with like results.

From these experiments Mr. Spencer was led to conclude, that the
appearances that are sometimes observed in the mines, and which have
been attributed to electrical action, might be simply and satisfactorily
explained without supposing the presence of two dissimilar metals, or
even metalliferous bodies, as the water found in the mines, and con-
taining salts of the different metals in solution, would, in their action
on a single metalliferous substance, generate electricity sufficient to
account for the deposition of crystals of the pure metal so frequently
found on the poorer copper ores.

* I have thrown out of the case the resistance to decomposition of the electrolyte in
contact with the zinc, as common to the three combinations.

TRANSACTIONS OF THE SECTIONS. 39

As an experimental illustration, he took a piece of pretty rich sul-
phuret of copper and placed it in a narrow glass vessel, half filled with
sulphate of copper in solution ; the sulphuret was immersed about half
its length in this solution ; common water, with a few drops of acid,
was then added in the manner before stated, taking care that it should
not intermingle with the cupreous solution underneath. The whole was
then placed in the dark, and left untouched for about a week.

At the end of that time Mr. Spencer examined it, and had the satis-
faction of observing that several portions of it had become covered with
very minute crytals of the pure metal : at the end of a fortnight still
more beautiful crystals had been deposited.

This experiment was repeated with water taken from a copper mine
in Anglesey and with similar results.

These experiments were adduced by the author in support of the
views of Mr. Fox.

Mr, Spencer exhibited a Cylindrical Battery, so as to include great
intensity in small space.

On the Artificial Crystallization of certain Metallic Carburets, as

extensive of the Theory of Crystallization. By Samuel Brown,

M.D..> Edinburgh.

The theory of the circumstances in which the phenomenon of cry-
stallization takes place, so far as these have been hitherto known, may
be expressed in these three practical maxims :

1st. When a body is slowly reduced to solidity from a state of
fluidity (gasiform or liquid), its particles congregate in such a manner
as to produce the crystallization of the substance concerned. This
includes crystallization by sublimation, fusion, and all the modifica-
tions of these processes.

2nd. When a body is slowly deposited in the form of solidity from
a state of solution in a fluid (gasiform or liquid), its particles mutually
arrange themselves in the crystalline mode of cohesion. This com-
prehends all cases of simple crystallization, as effected by the gradual
elevation or depression of the temperature of solutions, and by the
evaporation or dilution of the solvents.

3rd. When an insoluble solid body is slowly formed, whether by
synthesis or analysis, in a fluid, its particles assume the crystalline dis-
position about each other. To these the author adds a fourth.

4th. When the particles of a solid body are slowly evolved from the
decomposition of a substance of which it, or its elements, are chemical
constituents, they cohere in crystal, and that independently, both of
the fusion or solution of the body crystallized, and of the presence of
any fluid medium of molecular motion whatsoever. Thus, when an
infusible metallic carburet is slowly formed in a shut vessel from the
decomposition of the cyanide, it is procured of a transparent, very hard,
and crystalline structure.

40 REPORT— 1839.

The illustration of this general statement, and the exemplification of
the instance now cited by anticipation, were the objects of the author's
observations.

While engaged in examining the visible properties of these dark,
opaque, and uncrystallized products of the decomposition by heat of
the cyanides and sulphocyanides of iron, copper, lead, zinc, bismuth,
silver, tin, and manganese, specified above, the author noticed on one
side of the field of the microscope a minute transparent fragment,
close in structure, refracting the light of the mirror peculiarly, and
trembling with uncommon brilliancy under the play of the illuminat-
ing lens. It was in that prepared from the sulphocyanide of copper.
The specimen was searched, and many more such clear morsels
found, some of them having even attempted a regular form. These
little crystals in all chemical respects conducted themselves in the
same manner as the amorphous powder among which they had been
found.

Dr. Brown's experiments to determine on what their crystalline
structure depended, resulted in establishing the following formula :

Formula. Let a parcel of any cyanide (or sulpho-cyanide) be care-
fully dried and put in a green glass tube, the open end of which is then to
be drawn out, and the attenuated part bent at right angles with the con-
taining. Immerse it horizontally in a shallow sand-bath suspended
over a spreading gas flame. Apply the heat with such caution as
shall secure that the whole apparatus be always as nearly as possible
at the same temperature at the same times. Let the flame be thus
progressively raised till the material in the tube has been brought to
that degree of temperature which may be called its point of decompo-
sition, which may be indicated in the case of a sulphocyanide by the
appearance of bisulphuret of carbon, and in that of a cyanide by the
impulse of liberated nitrogen on any light body held over the open
extremity of the tube.

Whenever signs of decomposition have been observed, the flame
must be lowered as nearly as possible to that degree at which it is
able to communicate increments of heat equal to the decrements, by
radiation and conduction, of the apparatus. Continue the operation so
long as gas is extricated. In this way will the cyanide (or sulpho-
cyanide) have been decomposed, as nearly as manipulation can effect,
at its "point of decomposition"; the particles of resultant carburet will
have been slowly evolved one after another ; and, instead of throwing
themselves into a shapeless aggregation, will have affected the regu-
lated arrangement of crystallization.

" 1st. Carburets thus crystallized are like sands of large grain ; the
granules having, many of them, regular forms, generally double octo-
hedrons. Larger crystals may be formed, although I do not know
how their formation may be secured.

" 2nd. When prepared, they are opaline, or like semi-transparent
enamel. On being heated more strongly, they become perfectly
clear. I have heated them in the hottest blast of air and blast fur-
naces for hours without melting them ; without, indeed, producing

TRANSACTIONS OF THE SECTIONS. 41

any effect except that of completing their translucency and improving
their appearance.

" 3rd. When raised to a red heat in the air, they slowly combine with
oxygen, and yield the same products as the amorphous substances.
In all respects they comport themselves as the same carburets when
uncrystallized, except that, as might have been anticipated from their
hardness, they are far less susceptible of reaction. And hence a
specimen may be freed of uncrystallized powder by cautious heating
in the air, and subsequent washing with the common acids.

" These facts, besides their bearing on geological and other questions,
prove that the only essential condition of the crystallization of a body
is, that its particles be slowly segregated from any previous condition
whatever. This will appear to be more important when it is recol-
lected, that in all former experimental crystallizations there seemed
to be txoo elements, or essential conditions, viz. slowness of separation
of particles, with the presence of fluidity in some form or other, as
the medium of their easy motion."

Experimental Demonstration of the certain existence of Haloid Salts
in Solution. By Dr. George Wilson.

It was observed that all previous attempts to decide the question,
whether haloid salts do or do not decompose water, when dissolved
in it, had afforded no certain results, since none of the methods em-
ployed yielded an experimentum crucis. The object of this paper was
to show, that though the inquiry had long been abandoned as hopeless,
a demonstration can be given of the persistent haloid condition of the
dissolved haloid salts of the electro-negative metals. The mode of
experimenting followed was based on an important difference between
the two great classes of metals. The electro-positive metals, as po-
tassium, sodium, zinc, iron, &c., dissolve in the hydracids with the
evolution of hydrogen, indicating thereby (according to the more sim-
ple theory of the change) an attraction for the radicals of the acids su-
perior to that of the hydrogen which they displace ; the electro-nega-
tive metals, on the other hand, do not dissolve in the hydracids, nor de-
compose them ; they cannot, therefore, displace hydrogen, but should be
displaced by it. As the halogens or salt radicals have thus a less attrac-
tion for the electro-negative metals than hydrogen has, this body may be
employed to decompose their haloid salts. The action of uncombined
hydrogen on the dissolved salts was shown to be not of itself decisive
as to their true state in solution, but its effect on them when evolved
from an hydracid affords an unequivocal experimentum crucis. Gold
and its terchloride were chosen as examples of an electro-negative
metal and its haloid salt ; and hydrobromic acid was taken as the de-
composing re-agent. In anticipating their action on each other, it
appeared that if the chloride of gold became by solution in water an
hydrochlorate of the oxide, it should not be decomposed by hydrobro-
mic acid, which has a less attraction for all metallic oxides than hydro-

42 REPORT — 1839.

chloric acid has. But if it be persistent as a chloride, it should be decom-
posed by hydrobromic acid, since the chlorine and hydrogen are com-
bined with two bodies, gold and bromine, for which they have a less at-
traction than they have for each other ; they should therefore combine to
form hydrochloric acid, while the relinquished gold and bromine also
unite that a bromide of gold may be formed. When this experiment is
performed, the chloride is decomposed by hydrobromic acid, the bodies
added being the dissolved terchloride of gold, and hydrobromic acid ;
the products of the change are, the similarly dissolved terbromide
of gold and hydrochloric acid ; and the immediate proof of such a
change having occurred, is the alteration of colour which succeeds the
mingling of the two bodies. The solution of the chloride of gold has
a pale yellow tint ; the bromide has a dark red hue ; any conversion,
therefore, of the chloride into the bromide is indicated by the colour
of the liquid passing from pale yellow to dark red. To determine the
certainty of this decomposition, the liquid was separated, either by di-
stillation or by agitation with sulphuric ether, into the bromide of gold
and hydrochloric acid, which were respectively tested and ascertained
to be such.

The certainty of the decomposition having been determined, and its
occurence in atomic as well as in irregular proportions learned by re-
peated experiment, the theory of the change may now be considered.

The salt of gold, being a terchloride, will require three proportions
of hydrobromic acid for its complete decomposition. On the supposi-
tion of its dissolving as a haloid, its decomposition will occur thus :

Decomposition of Terchloride of Gold hy Hydrobromic Add.

( The figures express atoms.)

Terchloride f Gold, 1 -^ Terbromide of

of gold, 1. \ Chlorine, 3^-^^^.^-'""'^ gold, 1.

Hydrobromic f Bromine, 3--'^'^^---,,.^^^ Hydrochloric
acid, 3. \ Hydrogen, 3 /'^^''^-^acid, 3.

Again, let the liquid be supposed to contain a muriate of gold, it will
be thus :

Decomposition of Termuriate of Gold hy Hydrobromic Acid.

rr, • X 1 Hydrochloric acid, 3

Termuna e Iq 3 — ::^Water, 3.

of gold, 1. j^Jl J ^^^,^^---

Hydrobromic 1 Hydrogen, 3 " ~~-___Terbromide of

acid, 3. J Bromine, 3 ^~~'~~" gold, 1.

According to the former of these views, the hydrogen of the hydro-
bromic acid takes chlorine from chloride of gold, so that hydrochloric
acid is formed ; according to the latter, hydrogen takes oxygen from
the oxide of gold, and water is formed ; while hydrochloric acid, pre-
viously in combination, is set free.

By a reference to the diagrams it will be seen, that in each of these,

TRANSACTIONS OF THE SECTIONS. 43

the only two possible methods of explanation, we end by admitting the
production and presence of a true haloid salt, the terbromide of gold.
It cannot be declared possible that the bromide of gold, as soon as
formed, has decomposed water, and become an hydrobromate, since,
by reference to the lower diagram, it will be seen that the production
of the bromide, according to the Amphide theory, implied the re-solu-
tion of hydrobromic acid and oxide of gold into water and bromide of
gold. The production of water was declared essential to the change ;
its decomposition cannot therefore be assumed as equally possible, since
the previous half of the explanation would thus be negatived, and the
theorist should only exclude the bromide from the list of haloid bodies
by admitting the chloride, or vice versa. The nature and value of this
mode of experimenting is summed up in the following proposition : The
dissolved terchloride of gold is decomposed by hydrobromic acid, with
the production of terbromide of gold, in circumstances which make it
certain that one of these salts is a haloid in solution : but if one of
these be a haloid the other is also, and so are all the salts of the same
class.

The demonstration is further shown to be afforded in another way :
it will be seen, by reference to both diagrams, that each view recog-
nises the presence of bromide of gold and hydrochloric acid. But if the
bromide became a hydrobromate, it would at once be decomposed by
the hydrochloric acid ; it is permanent, however, and must therefore be
a bromide while in solution.

A similar inquiry was stated to have been followed out with the
haloid salts of platinum, and with equally decisive results ; and the
author observed that the method proposed would aiford an equally un-
equivocal demonstration for the haloid salts of all the metals which have
a less attraction for hydrogen than the radicals of the hydracids have ;
i. e. it would apply to all the electro-negative metals. It was further ob-
served, as an incidental conclusion from the experiments recorded, that
they afforded a direct proof of the quasi-metallic character of hydrogen,
so much insisted on by the advocates of the binary theory of salts ; and
that they supplied more direct evidence than any previous trials re-
garding this, since they not only demonstrate hydrogen to have the
power of displacing many metals, but at the same time assign to it, as
its proper place in its metallic character, a position intermediate be-
tween the electro-positive and electro-negative metals.

On the limits within v)hich the Atomic Weights of Elementary Bodies
have been ascertained. By Thomas Clark, M.D., Professor of
Chemistry in Marischal College and University , Aberdeen. [This
paper is given entire at the recommendation of the Committee of the
Chemical Section, confirmed by the General Committee.]

The atomic weights of elementary bodies, as they occur in the re-
ceived tables, commonly represent the mean result, or a selected result,
of the experiments on which they are founded. It may be now useful,

44 REPORT — 1839.

at a distance of about thirty years from the period when attempts to
ascertain such weights with accuracy were first made, to have placed
before us, not merely the mean or selected result of the fundamental
experiments, but also their highest and lowest results. The variations
are much greater than chemists in general are aware of.

To attempt giving a view of the variations in the atomic weights of
each elementary substance would occupy far too much time for an oc-
casion like the present. All that I propose is, by adverting to certain
compounds of lead, in illustration of the atomic weight of that metal
and of the atomic weights of sulphur, azote, and carbon, to afford some
idea of the limits within which the atomic weights of these four ele-
ments have been ascertained.

In proceeding to indicate such limits, I need not, in this presence,
express how much the selection of safe data requires the exercise of
circumspection. The results of only such experiments as have been
performed with the utmost care should be employed. By including
the results of experiments otherwise conducted, we increase the limits
of the recognisable variations, which is the opposite of desirable, with-
out thereby increasing the certainty of the mean or selected result.

The Protoxide of Lead.
The proportions of oxygen and lead in this compound have been
repeatedly examined by Berzelius. The mode of analysis ultimately
preferred by him, consisted in reducing the oxide by pure hydrogen
gas, at an elevated temperature, and weighing the residual metal. The
loss Avas accounted oxygen. In his last and most careful experiments,
he obtained, as the result of six experiments, for every 100* of oxygen,
the following quantities of lead :

Greatest 1295-70^

Mean 1294-24 > Weighed in air.

Least 1293-08 J

But inasmuch as, weight for weight, the protoxide of lead is more
bulky than lead itself, the oxide would, when weighed in air, be pro-
portionably more buoyed- up than the metal. Thus if 1394- grains of
lead were balanced in air against 1394- grains of its protoxide, the same
1394- grains of lead would, when transferred to a vacuum, counterpoise
1394-033 grains of the same protoxide. Hence, in the foregoing results,
the oxygen, instead of 100*, should be reckoned 100-033. By reducing
this 100-033 to 100-, and by reducing the lead in the same proportion,
we obtain of lead to every 100- of oxygen.

Greatest 1295-271

Mean 1293-82 > Weighed in a vacuum.

Least 1292-65 J

Berzelius has, more than once, observed that the circumstance of the
atomic weight of lead being about thirteen times the atomic weight of
oxygen, causes the slightest error in experiment to be very much mul-
tiplied in calculation. Thus the difference between the highest and

TRANSACTIONS OF THE SECTIONS. 45

the lowest atomic weight of lead is 2-62 ; yet this difference, great as
it seems, results from a difference of only one 74th of a grain in the
lead left from 100* grains of the protoxide. Considering that this dif-
ference represents the widest variation that occurred in the experi-
ments, I need not say how much accuracy the smallness of its extent
implies. It is calculation that so much magnifies this inconsiderable
experimental difference, and in two ways — first, whatever is subtracted
from the lead comes to be added to the oxygen, and the converse; and
second, the difference in the oxygen comes, when computed on the
lead, to be multiplied by about thirteen times, the atomic weight of
lead being thus much greater than the atomic weight of oxygen ; so
that, in these two ways, an error of only one in 7400* on the protoxide
increases to 2-62 on 1394* of the protoxide, or on 1294* of lead, or to
about one in every 500" of the metal. Thus the atomic weight of lead
comes to vary in a ratio fifteen times as much as the experiment
whence it is derived. Certainly it is an unhappy circumstance when
calculation so much magnifies the unavoidable errors of experiment,
more especially when, as will be seen presently to happen in the
instance of lead, the original variation comes to be complexified with
other variations, and the error in atomic weight comes to be commu-
nicated in aggravated amount from element to element.

The Sulphate and the Nitrate of Lead.

Berzelius converted known weights of pure lead into a solution of
the nitrate, and, adding thereto an excess of dilute sulphuric acid, he
evaporated the whole to dryness, and heated the mass to redness, so as
to obtain the dry sulphate of lead. Turner repeated the experiment
nearly in the same manner ; but he made allowances for some slight
corrections that were neglected by Berzelius. The weight acquired by
the lead, in becoming the sulphate, should be increased on account of
the buoyancy of the air, and should be diminished on account of the
solid impurities of the acids employed.

On 100' of lead the correction for buoyancy is -f-0125

for acid impurities —•0190 (Turner.)

Nett correction .... —-0065

Making allowance for this correction in the experiments of Berzelius,
100- of lead afforded of the sulphate,

Berzelius. Tui-ner.

146-3741 Tv/r 146-4301 ,;.

146-396 \ , f^l"^, 146-398 \ , ^^f"^,

146-433 J 1*^*01 146-375] l^^'^^l
146-451

The experiments of Turner, taken along with the three first of Ber-
zelius's, would seem to indicate that the last experiment of Berzelius's
affords too high an increase. From a comparison of the results ob-
tained by both chemists, the following quantities have been adopted in

REPORT — 1839.

the calculations in the sequel, as the experimental increase on 100' of
lead in becoming the sulphate :

Greatest 46-431
Mean 46-401
Least 46-374

A known weight of dried nitrate of lead was likewise, by Turner,
dissolved and heated with sulphuric acid, so as to form sulphate. Cor-
rections on account of the buoyancy of the air and of acid-impurities
having been made, 100- of sulphate of lead were produced from —
Nitrate.

1, 109-312

2, 109-310

3, 109-300

Mean 109-307

These results come very near each other. But according as 100- of
lead, in becoming the sulphate, increases 46-431, 46*401, or 46*374,
the proportion of lead in its nitrate will vary, on account of the uncer-
tainty of the composition of the resulting sulphate, altogether inde-
pendent of the small variation in the proportion of nitrate that pro-
duces a given weight of sulphate.

Greatest.
Sulphate 146*431

from
Nitrate 160-067
160-065
160-050

Sulphate 100-
from

Nitrate 109-312
109*310
109*300

(Mean) 109*3075

160*060

Mean.
146*401

160*035
160*032
160*017

160*027

Least.
146*374

160*005
160-002
159*987

159*997

146*431, 146*401, 146*374, being the quantities of the sulphate of
lead that were formed from 100* of lead, it follows that the quantities

of nitrate 160-067 159*987 should likewise contain 100- of lead.

Bringing then together the results of the experiments on the sulphate
and on the nitrate, it appears that the following are the increments of
weight that 100* of lead acquires in becoming,

Sulphate. Nitrate.

Greatest 46-431 .... 60-067
Mean 46-401 .... 60-027
Least 46-374 .... 59-997
The increase of weight that lead acquires in becoming sulphate, is
generally admitted to be due to the acquisition of one atom of sulphur
and four atoms of oxygen. In the case of the nitrate, however, while
the generality of chemists regard the oxygen acquired to be six atoms,
the azote is, by some, considered as one atom ; by others, as two.
With Dalton and Berzelius, I regard the azote as constituting two
atoms.

TRANSACTIONS OF THE SECTIONS. 47

The increase, then, acquired by one atom of load, will, in the case of
the sulphate, be the sum of one atom of sulphur and four atoms of
oxygen (S'04), and, in the case of the nitrate, be the sum of two
atoms of azote and six atoms of oxygen (A^Og). Starting from the
atomic weight of lead, varying as already given, the following table
exhibits the varying experimental increments corresponding to S'04
and to A^Og :

Greatest. Mean. Least.

On LEAD one atom, 1295-27 1293*82 1292*65

ItX CTCCtSG*

r Greatest 601-41 601-02 600*67

S'O^ <( Mean 600-73 600-34- 599-99

L Least 600-19 599-80 599-45

f Greatest 778-03 777-15 776-46

A^Oo I Mean 777-51 776*64 775-94

[Least 776-99 776*12 775-42

Deducting 400* for the oxygen in the sulphate, and 600* for the
oxygen in the nitrate, we obtain the following atomic weights :

Greatest. Mean. Least.

Lead, 1 atom. ... 1295*27 1293*82 1292*65

Sulphur, 1 atom. ... 201-41 20034 199-45

Azote, 2 atoms. ... 178-03 176-64 175*42

The differences between the experimental atomic weights of each of
these elements are

Between mean and extremes. Between extremes.

Lead +1-45 - 1*17 2-62

Sulphur +1*07 - -89 1*96

Azote (A2) +1*39 - 1*22 2*61

These differences are considerable. They show that there is an un-
certainty of + 1* in the place of units, in each equivalent, oxygen being
assumed at 100*. From the manner in which the atomic weights have
been sought, the difference in the instance of sulphur is evidently due
partly to the variations found in the atomic weight of the lead, and
partly to the variation in the increase that lead acquires in becoming
sulphate ; and the difference in the instance of azote is due not only
to the same two variations, but also to the varying product of the sul-
phate from a given weight of the nitrate. What portion of the differ-
ences between the mean and each extreme is due to each of these
causes, in the equivalents of sulphur and of azote, appears in the fol-
lowing table :

In sulphur. In azote.

On account of the oxide +*68 — *54 +*87 — -70

„ „ sulphate + -39 —-35 +-42 —-39

„ „ nitrate +-10 —'13

+ 1*07 -*89 +1*39 -1*22

48 REPORT — 1839.

The differences on account of the oxide are the most considerable ;
next those on account of the sulphate ; and the differences on both of
these accounts are ten times greater than what arises from the experi-
ments on the nitrate alone. Thus, in such researches, do errors cu-
mulate.

On reviewing the atomic weights thus ascertained, together with their
variations, there appear to me to be considerations entitling us to reject
some of the highest.

First, as to azote. A^ has been found as high as 178*03. But ad-
mitting the atmosphere to consist of 21 bulks of oxygen for 79 bulks
of azote, we are quite sure that A^ cannot be so much as 177* ; for
then the specific gravity of oxygen must be less than 1*100, which
would contradict all good experiments on the subject that have been
made. Therefore 177* and any number higher must be rejected as too
much for A^.

Next as to lead. By calculating from 1295*27, the greatest atomic
weight of lead, we obtain for A^, 178*03, 177*51, 176*99. But as even
this last and smallest number has been shown to be too high for azote,
so must 1295*27 be too high for lead. The next lower number found
by Berzelius was 1294*52, which affords,

A"-Os A2

Greatest 777*58 177*58

Mean 777*06 177*06

Least 776*54 1 76*54

But this mean and this greatest are evidently too high, for the
reason already mentioned. Even the smallest number (176*54 for A^)
corresponds with a specific gravity for oxygen of 1*1021, which is
below the received experimental results. Therefore I apprehend we
are entitled to reject the second as well as the highest of Berzelius's
experimental results for the atomic weight of lead. His remaining ex-
periments are four :

1. 1293*775

2. 1292*647

4. 1292*795

5. 1293*888

Mean 1293*276
Say,

Highest 1293*89
Mean 1293*27
Least 1292*65
Repeating the calculations on this basis, we have.

Greatest, Mean. Least.

On lead one atom 1293*89 1293*27 1292*65

Increase.

r Greatest 600*77 600*48 600*19

S'O^^ Mean 600*38 600*09 599*80

[Least 600*03 599*74 599*45

TRANSACTIONS OP THE SECTIONS. 49

Greatest. Mean. Least.

r Greatest 777-20 776-83 776-46

A^OJ Mean 776-68 776-31 775-94

[Least 776-16 775*79 775-42

The atomic weights hence deduced are,

Greatest. Mean. Least.

Lead 1293-89 1293-27 1292*65

Sulphur 200-77 200-09 199-45

Azote (A2) 177-20 176-31 175-42

The variations now, and the sources of them, are shown as follows:
In sulphur. In azote.

On account of the oxide +'29 —-29
„ „ sulphate + -39 —-35

„ „ nitrate

+ -68 --64 +-89 --89

Tartrate and JRacemate of Lead.
These two salts, containing the same ultimate elements, were care-
fully examined by Berzelius. His results are contained in the following
table, which is constructed on the same principle as those for the
sulphate and the nitrate :

Greatest. Mean. Least.

Protoxide 1393-89 1393-27 1392-65

A . , fGreatest 828*16 828-53 828-90

d.ra.9M''lKn<^ Mean 827-23 827-60 827-97

^'"^'^ "^^^LLeast 826-30 828-67 827-04

Allowing 12-6 for H-, which I consider to be the result warranted

by Berzelius's experiments, the following would be

The atomic weight of carbon;

Greatest 75-92

Mean 75-60

Least 75-28

On the relative Combinations of the Constituents of Cast Iron, Steel, and
Malleable Iron. By Dr. Charles Schafhaeutl, of Munich.

The author showed, that the purest carbon contained and retained
hydrogen, and sometimes azote, even at the highest temperatures, and
parted with neither of them, nor were its own internal and external
properties altered, except when it attacked the crucible, and combined
instead with oxygen, or aluminum, or silicon. He affirmed, that we
possessed no certain method of procuring pure carbon in the isolated
state, and that what we considered to be pure carbon was always, more
or less, in the state of carburet. The author described a new method
of obtaining graphite, viz. by running fluid puddling slag, or silicates

1839. E

50 REPORT- 1839.

of iron and manganese, over fragments of pit coal. After cooling, the
surface of the slag is always found to be altered, and to be covered
with a very easily separable layer of graphite, not only where the slag
actually touches the coal, but even where it comes in contact with the
smoke evolved from the coal. The formation of graphite commences
at a temperature lower than 1500° Fahr., and reaches its highest point
not much exceeding 2000°. Two different sorts of graphite were
produced in this way ; one, which he marked (A), was in elastic
scales, of the thickness of writing-paper, with a rather dull metallic ap-
pearance. The graphite marked (B) M^as of the thickness of gold-leaf,
and extremely light and unctuous to the touch. He found, that all
sorts of graphite lost their unctuosity and bright appearance by ex-
posing them to the action of concentrated hydro-fluoric acid. Graphite
(B) was found to consist of

Protoxide of iron 18*6000

Silica 7-6200

probably mechanically, but equally and invisibly intermixed with

Carbon 70-3421

Silicon 3-0744

Loss 00-3635

Graphite (A) gave.

100-0000

4-93 Silicon.

9-50 Iron.
85-45 Carbon.
00-12 Loss.

100-00

The quantity of oxides of iron and silica had been ascertained by
heating the specimens first with acids and caustic leys ; the quantity of
carbon, by burning the specimens with chromate of lead and chlorate
of potash ; and the silicon, by melting the powders with carbonate of
soda in a platinum crucible. He considered, therefore, the graphite
to be a carburet of silicon and iron ; and showed, by heating in a pecu-
liar way the remainders, left after the solution of iron in hydrochloric
acid of a certain specific gravity, that the chemical composition of cast
iron, in its two distinct species of gray and white cast iron, had direct
relation to the two specimens of graphite, and in all probability was
derived from similar origin, as indicated in the following table :

Graphite (B). Gray Cast Iron.

Smcon I Oxygen. Silicate of iron.
Carbon j Carburet of silicon.

e-,- I Silicet and alummet

Silicon > p .

/ A 1 • \ I of iron.
(Aluminum) J

SmcoT} Carburet of iron.

TRANSACTIONS OF THE SECTIONS. 51

Graphite ( A). White Cast Iron

Carbon

c-i- > Carburet of silicon.

cTbon^^^^^"^'^*°^^^°"-

Azote 1

Silicon > Carburet of silicon.

Carbon J

It was further shown, that all gray iron, produced by heated air as
well as by cold air, left a grayish white residue behind after treating it
with hydi'ochloric acid of a certain specific gravity. This remainder,
acted upon with caustic ammonia, evolved very rapidly pure hydrogen
gas, and alumina afterwards was found in the solution with a little
silica. The presence of aluminum in its metallic state, after having
been treated Avith acid, as well as the absence of all azote, seemed to
be one principal feature of gray iron of France as well as of England;
on the contrary, carbon, hydrogen, and azote are always present in
the remainders of ^vhiie iron, which remainders appear invariably of a
brownish colour; and azote is a constituent of steel as well as of
wrought iron. Further, it was explained, that silicon generally was
combined with carbon, and dissolved in the carburets of iron, and that
it was extremely difficult to produce an alloy of iron with silicon alone,
without the presence of a little carbon, aluminum, and other similar
bodies. Dr. Schafhaeutl found the molecules of all iron of a similar
form, belonging to the cubical system, and the largest not exceeding
0'0000633 of an inch in diameter, and that particularly upon the ar-
rangement of these molecules depends, in a great measure, the different
appearance of the different kinds. He denied that any graphite scales
were to be seen in gray cast iron ; yet, that under a magnifying glass
what appeared to the naked eye graphite scales, were really surfaces
and planes of crystallization, composed of pentagonal planes not wider
in the smallest diameter than 0'000355 of an inch, and composed of
the before-mentioned smallest or primitive iron molecules. According
to his statement, the molecules of the iron are arranged in the gray cast
iron in the most regular form, having all their surfaces in continuous
planes ; the most equal distribution of molecules appeared in hardened
steel ; collecting in fascicular aggregation in soft steel, and being loose
and longitudinally arranged in wrought iron. He stated that pure iron
could not be welded ; that the welding power of iron depended on its
alloy with the carburet of silicon, and also that the good and various
qualities of all the v.rought irons depended on the alloys of pure iron
with other metallic bodies ; and that the presence of most of the elec-
tro-negative metals had been generally overlooked in the published
analyses of iron. The presence of arsenic in Swedish steel, when forged
red hot, could be ascertained by its smell, as well as in the Low Moor
iron. The usual solution of iron under analysis, in order to separate
those metals from the iron, must be, for the necessary connection,
divided into two parts, — one to be treated with a current of sulphuret-
ted hydrogen, the other part dropped into the sulphydrate of ammonia,
and carefully digested. A small quantity of silica was more difficult
to separate from a large quantity of iron than generally seemed to be

REPORT — 1839.

believed ; and the real amount of carbon could only be ascertained by
Berzelius's method of burning iron in a current of oxygen, or mixed
with chlorate of potash and chromate of lead in a glass tube, used first
by Berzelius for analysis of organic bodies.

The author maintained that steel was an entirely mechanical produc-
tion of the forge hammer, which tore the molecules of certain species
of white cast iron out of their original position, into which the forces
of attraction, in respect to the centres as well as to the position of the
molecules, had arranged those molecules by the slow action of heat.
Steel, as it came out of the converting furnace or the crucible, was
nothing more or less than white cast iron, of which Indian steel, called
Wootz, was the fairest specimen.

The author finally gave an analysis of two specimens of cast iron and
one of steel. The first specimen was French gray iron, from Vienne,
Department de I'lsere, obtained from a mixture of pea-iron-ore with
red hematite, by means of coal from Rive de Gier and heated air, spe-
cific gravity 6*898. The second iron was Welsh iron, from the tin-
plate manufactory of the Maesteg ironworks, near Neath, in South
Wales, obtained from a mixture of clay iron-stone and Cumberland red
ore, by means of coke and heated air. It was silvery white, without
signs of crystallization : specific gravity 7'467. The third specimen
was a fragment of a razor forged in the author's presence, in the work-
shop of Mr. Rodgers, of Sheffield, of the specific gravity of 7-92.

Gray
French iron.

White
Welsh iron.

Steel.

Silicon

4-86430
1-00738
0-75130
0-00000
0-00000
0-00000
0-54000
0-17740
0-00000
3-38000
8900740
00-27222

1-00867
0-08571
traces.
0-00000
1-59710
0-00000
0-08553
0-32018
0-76371
4-30000
91-52282
00-31428

0-52043
0-00000
1-92000
0-93400
0-12100
traces.
0-00000
1-00200
048310
1-42800
93-79765
0-09382

Aluminum

Manganese

Arsenic

Antimony

Tin

Phosphorus

Carbon

Iron „

Loss...... .

100-00000

On the Composition of Idocrase. By Mr. T. Richardson.

With the view of assisting in explaining the discrepancies regarding

the composition of idocrase, which exist in our best chemical works,

the author presented in this communication the result of five analyses

of this mineral from specimens furnished to him by Mr. Wm. Hutton.

1. Specimen from Egg in Norway.
The colour was olive-green ; lustre vitreous, semi-transparent, and
fracture uneven. It was analysed in the usual way, every precaution

TRANSACTIONS OF THE SECTIONS. 53

being taken to insure accurate results, and the compos-ition obtained

was as follows :

Silica 38*75 contained 20*130 oxygen.

Alumina 17*35 8*102 "j

Protox. iron 8*10 ■ 1*8431 >19*979,

Lime 33*60 9*436 > 11 -859 J

Magnesia 1*50 *580j

99*30
which is most accurately represented by the formula,

7 (FO CaO MgO)3 Silg + 5 AIX),, SiOg.

2. Specimen from Slatoush in Siberia.

Colour light yellow-green ; vitreous lustre ; streak white ; graimlar
composition, and the individuals slightly connected, semi-transparent.
The result of the analysis approaches very closely that of magnus and
turrenkass, and differs completely from that of Mr. Ivanoe. It con-
tained as follows :

Silica 37*45 contained 19*454 oxygen.

Alumina 18*85 8*662"]

Protox. iron 7*75 1*7641 > 20*849,

Protox. manganese Lw-ir'tJ

Lime 35*25 9*901 f ^^^^^

Magnesia 1*35 *522j

100*35
which may be represented by the same formula as the above.

3. Specimen from Piedmont.

Colour sage-green ; vitreous lustre ; semi-transparent ; in part mas-
sive, terminating in small crystals ; fracture uneven. The result of
the analysis was.

Silica 39*25 containing 20*390 oxygen.

Alumina 17*30 8*079

Protox. iron 7*62
Protox. man. 3*50
Lime 32*25

Magnesia *47

11*823

}

19*902.

100*39
This also corresponds with the former.

4. Specimen of Vesuvianfrom Monte Somma.
It possessed the following characters : colour olive-green ; lustre

54 REPORT — 18S9.

vitreous, semi-transparent, well crystallized. The composition was,

Silica 37-90 containing 19'688 oxygen.

Alumina 18-15 8-4751

Protox.iron 4-89 1-112-j > 20-578.

Lime 34-69 ^'^"^^ > 19-103 i

Mairatst} 3-23 l-^^i "

98-86
5. Specimen of Egerane from Eger in Bohemia.
Its characters agreed with those of the other specimens, with the
exception of its colour which was cinnamon-brown, and its opacity.
The result of the analysis was,

Silica 38-40 containing 18-819 oxygen.

Alumina 18-15 8-4751

Protox.iron 7-40 1-684"] V 20-620.

Prot. manganese I 12-14 J

Lime 33-09 9-293 7^^^^^

Magnesia 3-02 1*168 J

100-06
The inference from the whole of these analyses is, that the composi-
tion of idocrase may be represented by the formula before given, viz.

7 (FO CaO MgO M0)3 SiOg + 5 Al^ O3 SiOj,
which may also be referred back to the fundamental formula of the
garnet, 3 RO SiOg + R2O35 SiOg. This conclusion suggests the idea,
that by attending more minutely to the exact representation of the
analytical results in the formula, new light might possibly be thrown
upon some points in the doctrine of Isomorphism.

Some observations on Meteoric Iron found in different parts of the
United States of America. By Charles Upham Shepard, M.D.,
Professor of Chemistry in the Medical College of the State of South
Carolina, and Lecturer on Natural History in Yale College, Con-
necticut.

During the last winter Dr. Hardy of Ashville, North Carolina, pre-
sented to the author a mass of apparently native iron, weighing seven
or eight ounces, that had been detached from a ball of about five inches
in diameter, which was found loose in the soil about five miles west of
Ashville, in Buncombe county. North Carolina. The specimen evinced
a decidedly crystalline structure, and even approached, in general figure,
that of a flattened octohedron. Its surface had a dissected or pitted
appeai-ance, occasioned by the removal of portions of the external
laminae during its separation from the original mass. The cells and
cavities thus apparent were perfectly geometrical in shape, being either

TRANSACTIONS OF THE SECTIONS. 55

rhomboidal, tetrahedral, or in the figure of four-sided pyramids. It
required the application of numerous and powerfvd blows to disengage
fragments from the specimen. The hammer slightly indented the sur-
face, and at length loosened sections of the external laminae, which
were detached by the aid of forceps. Their shape Avas commonly that
of acute rhomboids, considerably flattened in their dimensions, but ca-
pable of an easy division into regular octohedrons and tetrahedrons,
whose exactness of form rivalled the cleavage crystals of fluor. Some
of the plates separated into leaves nearly as thin as mica, which sub-
stance they even resembled in colour, (being silver white, inclining to
steel grey,) and were slightly elastic, though when twisted up they re-
tained their spiral form.

Prior to the separation of any fragments, the surface of the mass did
not afford the metallic lustre, but was coated by a thin blebby pellicle,
apparently of hydrous peroxide of iron. Those surfaces which were
exposed by cleavage lost their silvery grey lustre in the course of a
few weeks, and finally presented a rusty exterior, and even exfoliated
spontaneously, and separated into thinner layers and fragments.

In specific gravity the fragments at first detached yielded various re-
sults, from 6-5 to 7"5, and even 8-0, — a diversity no doubt dependent
mainly on the compression of the fragments produced during their se-
paration from the mass.

It was not until several days after Dr. Shepard commenced the che-
mical examination of the specimen, that it occurred to him that chlorine
might be an ingredient in its composition. Its existence, however, be-
came immediately apparent on the application of the usual test. Nor
was he less surprised on discovering, that after repeated digestions
of several hours at a time in aqua regia, a dark brown powder remain-
ed behind, which was no longer diminished in quantity by a continua-
tion of the process. It was separated from the solution, and ignited
with hydrate of potassa in a silver crucible ; water was then effused,
and the solution subsequently treated with nitric acid. A transparent
solution was instantly formed, from which ammonia threw down floc-
euli of silicic acid, coloured by peroxide of iron. A solution of potassa
was now added, and the peroxide of iron separated by the filter. The
clear liquid was rendered acid a second time, after which the addi-
tion of ammonia threw down white flocculi of silicic acid.

It was in this way that Dr. Shepard satisfied himself of the existence
of silicon in the Ashville meteoric iron, which element, so far as he
was informed, had never before been noticed in an unoxygenated state
in any natural body, either meteoric or terrestrial.

The following is a summary of the investigation in regard to this
meteoric iron :

Iron .... 96-5
Nickel . . . .2-6
Silicon .... 0*5
Chlorine . . .0*2

99-S,

56 REPORT— 1839.

with traces of chromium, sulphur, cobalt, and possibly of arsenic and
phosphorus.

The cabinet of Yale College contains one of the largest masses of
meteoric iron perhaps to be found in any collection. It was obtained
above twenty years ago from Texas, near the ridge between the Red
River and the Rio Bravo, at a place near the Pawnee village, situated
fifteen hundred miles above the confluence of the Red River with the
Mississippi. The greatest linear dimensions of the mass in question are
the following : three and a half feet long by three feet broad, and two
a half in height. It weighs between sixteen and seventeen hundred
pounds. Its surface exhibits but slight tendency to oxidation, and
presents numerous points of bright lustre.

The author ascertained, many years ago, from small fragments de-
tached from its exterior, that it contained about 9'6 per cent of nickel ;
and Mr. Benjamin Silliman, jun., having lately had occasion to saw off
a large plate from one extremity in order to engrave the donor's name
upon the mass, was struck with the highly crystalline appearance of its
more internal portions, and with the rapid tendency to oxidation which
such parts exhibited. This led him to detach small fragments and test
for chlorine, of whose presence he easily obtained the usual evidence.

On the Synthetical Composition of White Prussiate of Potash. By
R. Phillips, F.R.S.

On the existence of Fluoric Acid as a constituent of certain Animal
Substances. By G. O. Rees, M.D., F.G.S., ^c.

After the statements relating to this subject, published by Morichini,
Fourcroy, Vauquelin and Berzelius, Dr. Rees noticed the motives by
which he was led to search particularly for fluoride of calcium. His
experiments were conducted in the usual manner, by trying to obtain
the corroding action of fluoric acid on a plate of glass which was used
as a loose cover to a platinum crucible, containing the substance for
examination, mixed with strong sulphuric acid, a gentle heat being
applied to the bottom of the crucible. In this way several specimens
of human bone (both calcined and uncalcined) were subjected to ex-
periment, but in no instance could he obtain any action upon the glass.

The experiment which Berzelius recommends, in order to obtain the
corrosion of glass from bone earth, is to distil equal parts of strong
sulphuric acid and water upon it until the measure of water is brought
over. He states that the distilled liquor, if evaporated in the glass
receiver, will produce a corrosion. Dr. Rees repeated this experiment,
using 100 grs. of bone ash, and an ounce of the acid mixture, but
could obtain no action on the receiver by evaporating the distilled
liquor, nor was there any coiTOsion or opacity produced on any part
of the apparatus.

During the evaporation of the last portions of the liquor, dense
white fumes appeared, and there was some difficulty in vaporising the
whole.

TRANSACTIONS OF THE SECTIONS. 57

On neutralizing a portion with ammonia, and testing with nitrate
of silver, a yellow precipitate of phosphate of silver was thrown down.
A further examination showed the presence of sulphuric acid, and
traces of hydrochloric acid.

Finding phosphoric acid in this result of aqueous distillation, at a
moderate heat, the author suggested the possibility of its causing a
fallacy in the above mode of testing for fluorine, as it is well known that
glass of inferior quality will be corroded by the vapour of phosphoric
acid, and all the animal substances in which fluorine has been said to
exist, are particularly rich in phosphoric acid.

Having failed to detect fluorine in bone, Dr. Rees determined on
testing for it in the enamel of teeth, in recent ivory, and in the preci-
pitate obtained from the urine by means of lime-water. Two different
specimens of ivory gave no evidence of the presence of fluoric acid,
when carefully tested both before and after calcination ; and the author
was equally unsuccessful with the enamel of teeth and the precipitate
obtained from the urine by lime-water.

" In these experiments, when there was no action upon the glass, it
was always found that the addition of 0'3 gr. of fluoride of calcium
produced a strong and indelible stain."

Dr. Rees observes in conclusion, " I must express my firm convic-
tion, that if fluoride of calcium be an ingredient of fossil ivory^ it must
be regarded as an extraneous matter introduced during mineralization ;
and that no such constituent exists in recent ivory, the enamel of teeth,
human bones or urine.

" Since writing the above, I have had an opportunity of experiment-
ing on a specimen of fossil ivory, and have succeeded in obtaining
evidence of the presence of fluorine. I could not however ascertain
the locality from which this specimen was procured. When digested
with strong sulphuric acid, at a gentle heat, it produced a rapid and
indelible stain on the plate of glass used for the experiment.

Description of an Apparatus for the Analysis of Organic Substances.
By Prof. Hess, of St. Petersburgh.

The author proposed a modification of Prof. Liebig's apparatus, for
the analysis of organic substances, and stated it to be particularly useful
in the decomposition of substances which are susceptible of but slow
combustion, — of resins, fatty substances, liquids not very volatile, and
particularly of solid bodies. The only difierence in the mode of con-
ducting the analysis from that adopted by Liebig is the attachment at
both ends of the tube for combustion of a caustic potash apparatus,
and at one end of a gas-holder containing oxygen, upon the prin-
ciple originally introduced by Dr. Prout. A description of the appa-
ratus has been published in the Bulletin Scientijique, of St. Petersburgh,
accompanied by a figure. The heat is communicated by means of a
lamp, described and figured by Prof. Hess, in Liebig's Annalen der
Pharmacic for 1838.

58 REPORT— 1839.

On the Proofs of the existence of free Muriatic Acid in the Stomach
during Digestion. By Dr. R. D. Thomson.

The object of this communication was, to offer some experiments
which would appear to call in question the principle upon which those
were founded, from which Dr. Prout, and Messrs Tiedeman and Gmelin
came to the conclusion, that free muriatic acid exists in the stomach
of animals during digestion. To show that this point should not be
conceded, Dr. Thomson stated the following facts : Dr. Thomson
was first led to doubt the statement that free muriatic acid exists in
the stomach, from the circumstance of finding muriatic acid not so
efficacious as sulphuric in the treatment of alkaline indigestion. He
was then induced to examine the nature of the experiments of Dr.
Prout, and has arrived at results which seem to render them question-
able, if not to disprove the grounds upon which Dr. Prout arrived at
the conclusion, that free muriatic acid exists in the stomach of animals.
Having obtained a quantity of fluid from the stomach, he evaporated
it, and, according to the process of Prout, ignited the residue. On
dissolving the residue in water, and evaporating spontaneously, fine
crystals of carbonate of soda were obtained along with numerous
crystals of common salt. These could proceed only from one of two
sources, viz. the decomposition of lactate of soda, should any have
existed in the fluid, or from the decomposition of common salt. The
author was inclined to attribute it to the latter source rather than to
the former, in consequence of the very considerable number of crystals.
Pie had further found, in pursuing his experiments, and in accordance
with this result, that certain organic substances possessed the property
of decomposing common salt ; when tartaric acid and common salt are
heated together, copious fumes of muriatic acid are given out. The
same phenomenon occurs with citric and oxalic acids : sago also would
appear to produce some decomposition, and also saliva ; but the latter
experiment requires so much delicacy, that Dr. Thomson could not
affirm the fact with certainty.

On the Elementary Constitution of Organic Substances.
By the Rev. T. Exley, A.M.
Referring to the deductions from his hypothesis of the atomic con-
stitution of matter, which regard the union of atoms, and groups of
atoms, the author represented graphically, as well as by symbols, the
atomic arrangements in several substances which undergo remarkable
chemical changes. For example, in organic compounds, of many of
which water and olefiant gas are the true sources ; as,

1. Pyroxylic spirit H (H^ O) C H

2. Alcohol H^ C (H, O) C H^

3. Ether H, C^ (H„ O) C^ H^

4. Valerianic acid Hg C^ (C^ O3 H^) C4 H g

5. Ethal H16 Cs (H, O) Cg H.^

6. Sulpho-acetic acid H32 C,5 (SO3 H.^ O^ Cje Hgc

7. Stearine Hg^ €33 (C3 Hj CO) C32 Hg4.

TRANSACTIONS OF THE SECTIONS. 5U

The author remarks that there are at least ten substances found
whose extremes are the same as No. 1, thirty-three the same as No. 2,
and nineteen the same as No. 3. Of the others only a few have as
yet been discovered. The calculation of the specific gravity of those
in the gaseous form agrees with experiment in a manner which in-
duces the author to urge upon chemists the examination of the hypo*
thesis from which the graphical and symbolical results which he pro-
duced were derived.

The extremes after the first are successively doubled, each making
exactly one volume, to which the middle atoms, within the parenthesis,
contrijjute nothing : this remarkable result, the author observes, is
confirmed in all cases determined by experiment.

Experiments on Fermentation, with some general remarks.
By Dr. Uke.

A dispute having taken place between some distillers in Ireland, and
officers of Excise, concerning the formation of alcohol in the vats or
tuns by spontaneous fermentation, without the presence of yeast, the
Commissioners of Excise thought fit to cause a series of experiments to
be made upon the subject, and they were placed under Dr. Ure's gene-
ral superintendence. An experiment made on the 6th of October, 1837,
and another experiment commenced on the 12th of October, prove
beyond all doubt, that much alcohol may be generated in grain worts,
without the addition of yeast, and that also at an early period ; but the
fermentation is never so active as with yeast, nor does it continue so
long, or proceed to nearly the same degree of attenuation.

By employing a peculiar mash-tub, which he had devised. Dr. Ure
succeeded in raising the produce of spirit by this process to a perfect
accordance with the Excise tables.

The next experiments were made with a view of determining at what
elevation of temperature the activity or efficiency of yeast would be
paralysed, and how far the attenuation of worts could be pushed within
six hours, which is the time limited by law for worts to be collected
into the tun, from the time of beginning to run from the coolers.

It would appear from two experiments, that yeast to the amount of
5 per cent, is so powerfully affected by strong worts heated to 120°,
as to have its fermentative energy destroyed ; but that when yeast is
added to the amount of 10 per cent., the 5 parts of excess are not per-
manently decomposed, but have their activity merely suspended till the
saccharine liquid falls to a temperature compatible Avith fermentation.

Yeast, according to Dr. Ure's observations, when viewed in a good
achromatic microscope, consists altogether of translucent spherical and
spheroidal particles, each of about the 6000th part of an inch in dia-
meter. When the beer in which they float is washed away with a little
water, they are seen to be colourless ; their yellowish tint, when they
are examined directly from the fermenting square or round of a porter-
brewery, being due to the infusion of the brown malt. The yeast of a
square newly set seems to consist of particles smaller than those of

60 REPORT — 1839.

older yeast, but the difference of size is not considerable. The re-
searches of Schulz, Cagniard de la Tour, and Schwann, appear to
show that the vinous fermentation, and the putrefaction of animal
matters — processes which have been hitherto considered as belong-
ing entirely to the domain of chemical affinity — are essentially the re-
sults of an organic development of living beings.

Dr. Ure described at length the experimental processes by which
this position appears to be established.

On the theory of the formation of White Lead. By Mr. Benson.

The author, after describing at length the ancient and modern pro-
cesses for preparing white lead, proposed some new views of the
operation. The carbonate of lead formed by the common process is
anhydrous, amorphous, and contains one proportional each of carbonic
acid, oxygen, and lead. Now, as litharge is a protoxide of lead, it has
been thought, that in order to effect its conversion into white lead,
nothing more was requisite than to combine it with a due proportion
of carbonic acid ; and from this mistake a variety of fallacious pro-
cesses have been projected. The processes alluded to are founded
upon bringing the litharge into solution as a basic salt, and then pre-
cipitating it as a carbonate by the injection of carbonic acid. Painters
maintained, that this precipitate was not white lead. Chemists, find-
ing, by analysis, the correct proportions of protoxide of lead and car-
bonic acid, attributed the opinion of painters to prejudice ; but, by
microscopic observations. Dr. Ure has ascertained, that the carbonate
obtained by precipitation is semi-crystalline, and to a certain degree
transparent. The difference between white lead and precipitated car-
bonate may be illustrated by comparing them to pulverized chalk and
powdered marble ; both are carbonates, but the one is crystalline, the
other is not, and one is, consequently, less opaque than the other ; and
this difference is, of course, more appreciable, when the powders are
diffused thx-ough highly refracting media, such as oil. There is one
mode by which this difficulty may be avoided. The rationale of both
the processes, of that which produces the crystalline, and of that
which produces the amorphous carbonate, is the same. In both, the
lead is converted into basic acetate — in both, the salt is decomposed
by carbonic acid, but in the former the process is modified by the
pressure of water. In the one, the carbonate has been deposited from
a solution — in the other, the particles, never having departed from the
solid state, have not been at liberty to arrange themselves symmetri-
cally. In order, therefore, to produce amorphous carbonate, or white
lead, from litharge, it became necessary to present to the oxide of lead
a quantity of acetic acid so minute, that an insoluble basic salt should
be formed, with a quantity of moisture merely sufficient to determine
the action of the carbonic acid. The process would then resemble, in
all respects, the ordinary one, except that in the one the lead has been
previously converted into oxide, in the other, the formation of the

TRANSACTIONS OF THE SECTIONS. Gl

oxide goes on simultaneously with that of the carbonate. The process
has been carried out on a scale of considerable magnitude at Birming-
ham Heath. The quantity of acetic acid used is less than 1 -300th
of the weight of the litharge, and the quantity of moisture found to be
most advantageous is such as will just render the litharge sensibly
damp to the touch. A purer and more economical source of carbonic
acid than bark has been found in the combustion of coke, and power-
ful machinery has been applied to facilitate the process, by exposing
new surfaces to the action of the gas. The result has been, that the
process is completed in as many days of the ordinary one requires
months, and the product is of a purer white, and in opacity or body,
and all other respects, at least equal to the usual white lead of com-
merce.

One or two other facts deserve mention, which are not generally
known. It is singular that if the protoxide of lead known as massicot,
and the protoxide known as litharge, be exposed to a high tempera-
ture, approaching to a red heat, the massicot will rapidly absorb oxy-
gen, and become the ordinary red lead of commerce ; while the same
process goes on exceedingly slow with the litharge, if at all ; but, on
the other hand, if massicot and litharge be moistened with dilute acetic
acid, and exposed to carbonic acid, the litharge will be converted into
carbonate before the massicot is much affected. Another fact is, that
white lead and oil combine with so much energy, that if linseed oil be
poured upon a large quantity of white lead, and the mass be left un-
disturbed for a few hours, the temperature will become so elevated,
as to carbonize the oil, and render the whole perfectly black. It seems
also not generally known, that white lead possesses the power of de-
stroying the colouring matter of linseed oil. If sulphate of barytes be
mixed with one portion of oil, and white lead with another portion,
the latter will appear comparative white. If the two mixtures be
allowed to remain for some days undisturbed, a quantity of oil will
gradually rise to the surface of both. In the former, the supernatant
oil will have undergone no change ; in the latter, the oil will be nearly
deprived of colour, and will have acquired the degree of rancidity
termed by painters fat. The colouring matter has not combined, as
might have been expected, with the white lead, for if this be dissolved
by the agency of a weak acid, the disengaged oil will also be found
to have been bleached. A large quantity of white lead is required to
produce this effect, and the precipitated carbonate is less efficient than
the white lead of commerce.

On Matias Bark, By Dr. Mackay.

Dr. Mackay read a communication upon a bark which he had lately
received from South America, and stated to possess febrifuge qualities
equal to those of the best Peruvian bark, for which it has been success-
fully substituted.

Dr. Mackay submitted to the inspection of the Section specimens of
two different oils, obtained from the bark by distillation with water,

62 REPORT— 1839.

which, though existing in the same plant, and procured by the same
process, present marked distinctions.

The one, being of lower specific gravity than the water, floated upon
the surface of that which distilled along with it ; while the other,
being considerably heavier, sunk to the bottom of the receiver. Both,
when fresh, were transparent and colourless ; but in a few days they
changed to a yellow colour, the heavier assuming a deeper tinge than
the other.

In smell the oils differ perceptibly, that of the heavier being fatty
and unpleasant, while the odour of the lighter is aromatic and agree-
able. In taste they are equally acrid and disagreeable. The specific
gravity of the lighter oil is 0-949, that of the heavier 1*028, both
having been examined several days after their preparation. Upon
exposing them to a temperature of 18° Fahr., no effect was produced
upon the lighter oil; but in the heavier a great quantity of sparkling
needle-shaped crystals were observed, which, however, speedily dis-
solved upon the phial being removed out of the freezing mixture.
The mineral acids rapidly decompose them, converting both oils into
fluids of a deep red colour.

In a chemical point of view the oils referred to are interesting,
upon account of their presenting such marked distinctions in colour,
smell, specific gravity, and the effect of cold upon them, although they
are the produce of the same plant.

On an improved method of graduating Glass Tubes for Endiometrical
purposes. By Charles Thornton Coathupe.

The instrument employed by Mr. Coathupe for this purpose consists
of a truly-bored cylindrical tube of iron, into which an iron piston is
accurately fitted. Upon the rod of the piston a screw was cut with
a good pair of dies, throughout its entire length. The rod is then
filed into a triangular form, leaving a sufficiency of the threads of the
screw at the rounded angles for an iron nut to traverse with security
and freedom.

To the upper extremity of this iron cylinder a cap of the same metal
is screwed, and into this cap is screwed an iron stop-cock: to the stop-
cock is attached a glass measure, with a narrow lip, by means of an iron
connecting socket.

Near the opposite extremity of the cylinder an iron diaphragm, of
about a quarter of an inch in thickness, is inserted, and is fastened in
its place by a side screw or pin, and through this diaphragm a trian-
gular-shaped hole is made, through which the piston rod can slide
easily up and down, but without lateral shake.

Below the diaphragm, and at the extremity of the cylinder, the nut
is inserted, whose action propels or retracts the piston, without the pos-
sibility of the piston itself deviating from a right line.

This nut enters the cylinder to the depth of about half an inch, and
around the entering part a deep V-shaped groove is turned, into which
the pointed ends of three steel screws enter through the exterior of the

TRANSACTIONS OF THE SECTIONS. 63

cylinder at equal distances, in such a manner that the nut can be re-
volved freely, but cannot be otherwise displaced.

From the entering part of the nut a projecting portion forms a
shoulder, which is graduated into equal parts. (This projecting por-
tion may be of any diameter greater than that of the cylinder.)

On the exterior of the cylinder an index is fixed, by means of which
any number of revolutions of the nut, or any number of equal parts
of a revolution, can be ascertained.

To prepare this instrument for use, the piston is to be retracted to
its lowest position, and the cylinder is to be filled with mercury (with-
out air bubbles) by pouring a sufficient quantity of this metal into the
glass that is attached to the stop-cock, and turning the plug for its ad-
mission within the cylinder.

If, when the cylinder is fuU, and while some mercury still remains
within the glass measure, we turn back the plug of the cock, we
get the air-way of the plug filled with mercury ; and by pouring off
the superfluity, we have the instrument in a proper state to commence
graduating any tube for laboratory purposes. Thus, if the tube to be
graduated be about one third of an inch in diameter, if we open the
communication between the cylinder and the measure and propel the
piston by one whole turn of the nut, and then close the communication
between the cylinder and the measure by turning the plug of the cock,
we have within the measure a quantity of mercury, which, when poured
into the tube to be graduated, will give a tolerably long space for the
first division ; and such similar spaces may be successively marked by
repeating the process, until the whole tube be equally divided from
end to end.

Notice of an Apparatus for determining the quantity of Carbonic Acid
Gas in deteriorated atmospheres, ^y Charles Thornton Co athupe.

The apparatus consisted of a glass tube of about 24i inches in length,
and having an internal diameter of about half an inch. It was terminated
at each extremity by a brass cap, into each of which a brass stop-cock
was firmly screwed. The glass tube was divided into 175 equal parts,
by equal measures of mercury; and these divisions were numbered
upon opposite sides of the tube in such a manner, that let either end be
uppermost, the graduations might be instantly read. Every experiment
could thus be tested by a double reading, by simply inverting the tube,
and waiting a few seconds until the liquid employed for any examina-
tion had drained to its ultimate level.

The liquid reagent to be employed was stated to be either a clear
saturated solution of quick lime in distilled water, or any aqueous solu-
tion of potassa, soda, or baryta.

The mode of using the tube for ordinary purposes was described as
follows :

Fill the tube with the air to be examined, by any of the well-known
means, and close the stop-cocks.

Pour a drop or two of the reagent that may be preferred into the

64 REPORT— 1839.

terminating orifice of either of the cocks, so as to fill the space between
its extremity and the plug, and retain this liquid by the end of the
fore-finger. Insert the extremity thus prepared into the vessel that
contains the preferred reagent, and remove the finger. Turn the plug
of the inserted stop-cock for the admission of the reagent. Apply the
lips, or an exhausting syringe, to the orifice of the upper cock, and
commence the process of exhaustion. Gently turn the plug of this
upper cock during the exhausting process, and when the reagent has
risen so as to occupy 30, 40, or more of the lower divisions of the tube,
turn back the plug, and close the upper stop-cock. After a moment's
pause, close the lower stop-cock also. Note the number of divisions
unoccupied by the reagent, the tube being held upright.

Apply the finger to the lower orifice of the cock which has been
immersed, in order to retain that portion of the reagent which will
occupy the space below the plug. Agitate the tube with its contents.
Immerse the same end of the tube again in the vessel containing the
reagent, and remove the finger. Turn the plug of the lower cock, and
watch the rise of the liquid within the tube until it has attained its
fixed level. Then close the stop-cock, by turning back the plug, and
replace the finger. Agitate well.

Repeat this simple process until the reagent ceases to absorb air
from within the tube. Then suspend the tube by a loop of wire from
a pin or nail fixed into some convenient corner of the wall, until the
interior surface has become drained, and a permanent level established.
Now open the upper cock, when a small quantity of air will rush into
the tube to relieve the tension, and with it, generally, a single drop of
the reagent that had occupied the small space within the bore of the
upper cock beneath its plug.

The difference between the number of divisions, or parts, first ob-
served to be unoccupied by the reagent, and the number of parts lastly
observed to be unoccupied, will be the number of parts of carbonic
acid gas that was contained in the number of parts of air first observed.

It will be evident that a correction for tension will be necessary to
complete the process. This can be easily obtained ; and a table once
supplied, and entered in the laboratory note-book, will suffice for all
experiments with this instrument.

Mr. Coathupe explained a process by which the operator may con-
struct such a table for himself.

On a New Safety Lamp. By the Baron Eugene de Menil.

The peculiarity of this lamp consists in its open chimney, the prin-
ciple of small apertures being employed only for the admission of air,
on each side of the wick, through tubes capped by metallic gauze. The
strong flint glass cylinder inclosing the flame is protected by a dozen
small bars of tinned iron. The oil is kept in the lamp at a constant
level. The chimney, which rises above the general body of the lamp,
is contracted at the summit and covered (not closely) by an arched

TRANSACTIONS OF THE SECTIONS. 65

piece of metal. A reflector is placed within the glass cylinder to di-
rect the light.

In this lamp the flame is never extinguished : in an explosive atmo-
sphere loud noises give indication of danger : it is of cheap construction,
and economizes oil, but cannot be intrusted to the workmen who are
engaged in drawing coals along the galleries of the mine.

It was stated that this lamp had been favourably reported on by M.
Charles Combes, Ingenieur des Mines.

Notice of a Chemical Abacus. By Dr. D. B. Reid.

This instrument consisted of a frame of wood, across which wires
were placed, and upon which beads were strung, as in the instrument
which is employed by Chinese clerks, and is to be found in most
museums. Each wire corresponds to a chemical element, and the
beads to atoms, while the names of the elements are placed on the
frame at the extremities of the wires.

Remarks on Gas-Lighting. By the Count du Valmerino.

GEOLOGY.

On the Formation of Local Museums. By William Sharp, Esq.,
F.R.S., F.G.S., F.R.A.S., President of the Bradford Philosophical

Society, ^c, Yorkshire.

The author, after deprecating the heterogeneous nature of the col-
lections in local museums, proceeds to point out the plan recommended
by himself, and adopted by the Bradford Society, in which it appears
that the primary object is a collection of the natural objects of the di-
strict within fifteen miles of the town. The museum is intended to in-
clude geological specimens illustrative of the structure of the neigh-
bourhood, and in reference to quarries, manufactures and agriculture ;
the vegetable productions, with a view to improvements in cultivation ;
the animals of the district ; and facts relating to the meteorology, po-
pulation, manufactures and general statistics.

On the Origin of the Tubular Cavities filled with Gravel and Sand,
called " Sandpipes" in the Chalk near Norwich. By C. Lyell,
Esq.,F.R.S., V.P.G.S., with Additional Facts by J.B.Wigham,^*^.
The chalk near Norwich is covered with ferruginous gravel, sand

and loam, occasionally containing crag shells. The surface of the
1839. F

66 REPORT — 1839.

chalk beneath the gravel is very irregular ; in some places tubular
hollows, having the form of inverted cones and filled with sand and
gravel, extend downwards into the chalk. They vary in width from a
few inches to eight yards and upwards, and in depth from a few feet
to more than sixty. Some are tortuous, but most of those at Eaton,
near Norwich, are perpendicular. The materials filling the pipes agree
precisely with those covering the chalk, with the exception, that in the
pipes they are unstratified. The pebbles in the gravel consist of
rounded flints and quartz ; but no shells or pieces of chalk, or any
calcareous substance, occur in the pipes. In general, coarse sand and
pebbles occupy the central part of each pipe, while the bottom and
sides are lined with a fine ferruginous clay, destitute of calcareous
matter, but permeable by water. The chalk for a short distance ai-ound
the sandpipes is moist and softened, and slightly discoloured by an in-
termixture of clay. Further from the pipes it is white and perfectly
soluble in acids. Those pipes, whose diameter is less than a foot and
a half, are often crossed by horizontal layers of flint nodules, which
have remained in situ, while their chalky matrix has been removed.
The author hence infers, that the pipes were formed by the corroding
action of water containing acid. But it is clear that the tubes were
not first excavated to their present size, and then filled with gravel,
for in that case the nodules of flint derived from the chalk would have
fallen to the bottom of the larger cavities, — but this never happens,
the larger flints being always dispersed irregularly through the sand
and gravel which fills the tubes. Mr. Lyell therefore infers that the
excavation and filling of the tubes proceeded contemporaneously and
gradually, and that thus the flint nodules, when removed from their
matrix, subsided upon the sand and gravel which had previously sunk.
This is further proved by the fact, that the horizontal strata of gravel
are sometimes seen to bend down into the mouth of a pipe, and there
become vertical. Mr. Lyell is of opinion, that some of the larger
tubes (if not the smaller ones also) have been caused by springs
charged with carbonic acid, rising through the chalk. The fine layer
of clay, which coats the surface of the tubes, may have been deposited
by the percolation of rain-water at a later period ; and some of the
finer particles, being carried into the chalk itself, would cause the dis-
coloration of that rock near the pipes.

It was further stated by J. B. Wigham, Esq., in a letter to Mr. Lyell,
that examples of slanting and tortuous sandpipes occur near Heigham.
At Thorpe there is a pipe which penetrates both the chalk and the
superincumbent crag, the whole being covered with the usual gravel.
The clay lining is found throughout, and over this lining is a thin
stratum with impressions of shells. Near Norwich many springs come
up in the chalk, and sandpipes are always found near them*.

* For a fuller statement on this subject, with illustrations, see Phil. Mag.,
No. 96, p. 258, October 1839.

TRANSACTIONS OF THE SECTIONS. 6/

Description of a Section across the Silurian Jtocks in Westmoreland^
from the Shap Granite to Casterton Fell. By J. G. Marshall,
Esq., F.G.S.

The object of this paper was to explain the order of superposition of
a series of strata exhibited in Westmoreland, and to identify them, by-
means of their organic remains, with several members of the Silurian
system as defined by Mr. Murchison. The general strike of these
strata is from S.W. to N.E., and their prevailing dip toM^ards the S.E.,
interrupted, however, by many faults and reversals of dip, which are
described in detail. The following is the descending order of succes-
sion, deduced from the section here described.

1 . Carboniferous limestone, which at Kirkby Lonsdale overlies con-
formably the old red sandstone, and on the E. of Casterton Fell reposes
unconformably on the Blawith slate. In Kendal Fell it rests uncon-
formably on the Benson Knott rock. 2. Old red sandstone breccia,
forming cliffs on the E. side of the Lune. 3. Red or gray tilestones,
with nodules of cornstone, occurring in the bed of the Lune from
Beckfoot to Killington ; these beds contain but few fossils. 4. The
Benson Knott Rock, composing Benson Knott and two other anticlinal
ridges on the N.W. of Kirkby Lonsdale, consists of a compact, gray,
arenaceous slate with an irregular cleavage chiefly in the direction
W.N.W. and E.S.E. It contains numerous fossils, which have been
found by Mr. Sowerby to agree with those of the Upper Ludlow rock.
5. The Blawith slate, a hard, gray, siliceous slate, with a prevailing
cleavage from N.N.E. to S.S.W. This rock is 4000 or 5000 feet thick,
and at Blawith on Coniston Lake contains a thin bed of limestone with
fossils. 6. The Coniston limestone, consisting of blue flagstone, black
slate and blue limestone, the latter with numerous fossils. These beds
are much compressed, altered and contorted where they abut upon the
Shap granite; but are better displayed towards the S.W. in Sleddale,
Kentmere and Coniston, the fossils from which place have been iden-
tified by Mr. Sowerby with those of the Caradoc sandstone. Mr.
Marshall considers both the Blawith slate and the Coniston rocks to
belong to the Lower Silurian series ; and if the Benson Knott rock has
been satisfactorily identified with the Upper Ludlow rock, it appears
that the Middle Silurian series is wanting in the district here described.

The Coniston limestone is underlaid by the Cambrian system of
Cumberland, which has been described by Professor Sedgwick.

On a Basaltic Dyke in the Vale of Eden. By J. A. Knipe, Esq.

The Vale of Eden, or plain of East Cumberland, lying at the base of
the carboniferous limestone of the Pennine chain on the east, and the
group of primary mountains of the lake district on the west, consists of
f2

68 REPORT— 1839.

new red sandstone, much obscured by diluvial and alluvial deposits.
Gypsiferous beds are exposed at Cotehill and other places. At Broad-
field the subjacent carboniferous limestone is brought up and tilted at
an angle of at least 40°. Dip south. Commencing at its most western
point on the east side of the river Petterell at Petterell's Crook, about
six miles south of Carlisle, a columnar mass of globular concentric
balls of basalt is seen, which is again exposed on the Penrith road and
on the summit of Great Barrock. Continuing this line the dyke is
traced at Armathwaite, Combe's Peak, Stony Croft, Cringle Dyke, Ren-
wick, Ravenswater, Hartside Fell, and disappears about half a mile
south of Tynehead smelting-mill. The length of this dyke is twenty-
two miles, its width twenty to thirty yards ; and as its course almost
coincides with that of the great Cleveland dyke, the author suggests
that it is not improbable that they may be connected.

On the Geological Horizon of the Rocks of S. Devon and Cornwall,
as regards that Section of the great Grauwacke Group comprised in
the counties of Somerset, Devon and Cornwall, By the Rev. D. Wil-
liams, F.G.S.

The author first combats the opinion expressed by Mr. Weaver in
the Philosophical Magazine, third series, vol. xv. p. 109, that the culm
strata of Devon are unconformable to the trilobite slates which un-
derlie them. He shows that the two examples of unconformity ad-
duced by Mr. Weaver, at Rumson Lane and Muddle Bridge near
Barnstaple, are due to local derangement of the strata, and that the
general conformity of these two series of rocks is proved by numerous
observations in other places. The connecting link between them is
the " Coddon Hill Grit," containing elliptical masses of " Posidonia
Limestone," and repeatedly alternating with the slate rocks below and
the culm strata above, along the north borders of the central trough,
and on the south margin abrupted through the plant-bearing beds and
the overlying Cornish killas ; its broad anticlinal line thus constituting
the southern border, extending from Bos Castle on the sea to the green-
sand and chalk-flints of Haldon near Exeter. These Coddon Hill
grits, Posidonia limestones and floriferous beds, after repeated alterna-
tions and mineral gradations, are eventually overlaid by the slates of
Cornwall, — a fact, he states, which is well shown at St. Mellion and
Pillaton on the south of Callington, and about Pentilly Castle on the
west bank of the Tamar three miles below Calstock, where a good sec-
tion of the St. Mellion and Pillaton rocks is exhibited. Mr. Williams
refers the whole of the fossiliferous and other slates and limestones of
S. Devon and Cornwall to this intermediate part of the series, which
he considers to be somewhat older than the old red sandstone and car-
boniferous limestone of other parts of England, — a view in which he
considers himself fortified by the mountain-limestone type of many of
the fossils from the Plymouth limestone. The strata of this region are

TRANSACTIONS OF THE SECTIONS. 69

thus shown to be much younger than has been commonly supposed,
and the elvans or trap dikes must be of a still more recent date, as
they are seen to produce alteration in the new red sandstone.

Note on the Organic Remains of the Limestones and Slates of South
Devon. By R. A. C. Austen, Esq., F.G.S.

Bronn, in the conclusion to his Lethcea Geognostica, corrects his
former opinion, that the limestone of Torquay and Bradley was the
equivalent of the mountain limestone [Bergkalk]. Mr. Austen's ob-
ject in the present communication, is to show to how great an extent
the organic remains of the limestone of S. Devon are identical with
those of the Eifel. He gives a list of twenty-seven species which are
common to both districts. The three species, Pleurodictyum prohle-
maticum, Cyrtia trapezoidalis, and Calceola sandalina, are announced
for the first time as British fossils ; together with Brachiopoda, belong-
ing to the sub-genus Trigonotreta. From a study of these fossils Mr.
Austen concludes that the limestones of S. Devon are equivalent to
those of the Rhine, and also to certain strata in the S. of Ireland and
at St. Sauveur in Normandy. He considers the whole to be rather
older than the carboniferous series, and alludes to the great difficulty
of finding an appropriate designation for them.

On the Economy of Fuel. By Mr. Thomas Oram.
Dr. Buckland communicated the results of Mr. Oram's further ex-
periments on his method of manufacturing fuel from the waste coal-
dust, by which it appears a greater degree of heat is obtained (a very
small quantity of smoke escaping, with but little residue in the form
of ashes or clinkers,) than from the coal from which the dust was taken.
A saving also of one third in bulk is effected, which circumstance
especially adapts it for steam-navigation. The method by which the
fuel is prepared is as follows : one ton of dust-coal, 200lbs. of river-
mud, 40 lbs. of coal-tar, 3()lbs. of lime, 30 gallons of water, the whole
mixed together, and pressed into the form of bricks.

On Remains of Mammalia in tJie Crag and London Clay of Suffolk.
By C. Lyell, Esq., F.R.S., V.P.G.S. ^c.

The teeth of several species of mammalia have been obtained by
Mr. W. Colchester and the Rev. E. Moore from the crag at Newbourn
in Suffolk. They have been referred by Mr. Owen to a species of
leopard, a bear, and a small ruminant. They are all more or less
broken, and were found in company with the teeth of fishes of the
genus I^amna. It has not been positively ascertained whether these
mammalian remains were imbedded in the crag itself, or in ct^rtahi

70 REPORT 1839.

fissures which are filled with detritus of a later date ; but Mr. Lyell
inclines strongly to the former opinion*.

Mr. Lyell then mentioned the discovery, by Mr. Colchester, of the
tooth of an opossum in the London Clay at Kyson, near Woodbridge.
It was found, along with the teeth of Lamnce, in a bed of sand about
ten feet thick, covered by seventeen feet of London clay, and the
whole overlaid, at a short distance, by the red crag. Mr. Owen con-
siders this tooth to belong to a species allied to the Virginian Opos-
sum. Further search has since been made on this spot by Mr. Col-
chester, accompanied by Mr. Wood; and part of a jaw, with a molar
tooth, has been found, which Mr. Owen has decidedly referred to an
extinct Quadrumane allied to Macacus. (See Magazine of Natural Hi-
story, new series, vol. iii. p. 446.) This is the first instance of the oc-
currence of quadrumanous mammals in deposits of the eocene period ;
and it is thus proved that this order of animals existed long anteriorly
to the human racef .

On the Discovery of an Ichthyosaurus. By Mr. W. Marrat.

In this communication Mr. Marrat announced that his son, Mr. F.
P. Marrat, had lately met with an ichthyosaurus in the lias limestone
at Strensham, near Tewkesbury. The fore paddles were eleven inches
long, and eight broad ; the hind paddles seven inches long, and five
broad. The ribs were forty-six in number, and the largest vertebrae
rather more than two inches in diameter.

On Marine Shells found in Gravel near Worcester.
By Jabez Allies, Esq.

Mr. Allies exhibited a series of the marine shells of existing species
which have been found in the gravel near Worcester since the publi-
cation of Mr. Murchison's Silurian System, in which work their occur-
rence, in this locality, is first noticed. At Bromwich Hill, on the west
of Worcester, rolled shells of Turritella ungulina and Cardium *edule
have been found beneath twelve feet of gravel at about fifty feet above
the Severn. Bones and teeth of the elephant and rhinoceros occur in
the same bed of gravel. At Kempsey, four miles S. of Worcester, the
Turbo littoreus has been found (in addition to the shells enumerated
by Mr. Murchison at p. 533 of his work) beneath about twelve feet of
gravel, from fifteen to twenty feet above the Severn.

* For a full account of the position of these fossils with figures of the same,
see Taylor's Annals of Natural History, No. 23. p. 186, Nov. 1839.

f For the details of this paper and illut^tvations of the organic remains, see
papers by Mr. Lyell and Professor Owen, ibid, pp. 189, 191.

TRANSACTIONS OF THE SECTIONS. 7^

On the Topography of Ancient Tyre. By W. R. Wylde, Esq.

Queries respecting the Gravel in the neighbourhood of Birmingham.
By H. E. Strickland, Esq., F.G.S.

The author commenced this paper by referring to the division of
superficial gravel into marine and fluviatile., which he had found to
prevail in the S. of Warwickshire and Worcestershire. (See Reports
of the Sections, vol. vi. p. 61.) In the hope of ascertaining how far
the same division v/ould hold good in the neighbourhood of Birming-
ham, he proposed the following queries, to which, however, no answers
were given.

1. Does the gravel near Birmingham ever contain chalk-flints, frag-
ments of oolite, &c., which may indicate a southern origin, or is it
purely of northern extraction ?

2. Does it ever contain marine shells ?

3. Are these shells of existing or extinct species ?

4. Does it ever contain bones of land animals, or freshwater shells ?

5. What are the circumstances of position, material, &c., of the
gravel (if any) in which mammalian bones or lacustrine shells are
found, and is it distinguishable in any respect from the gravel in which
marine remains are found ?

6. Are mammalian remains ever found in company with marine
shells ?

On Microscopic Vegetable Skeletons found in Peat near Gainsborough.
By Mr. Binney, of Manchester.

Mr. Bowman read a paper on some skeletons of fossil vegetables
found by Mr. Binney in the shape of a white impalpable powder, under a
peat-bog near Gainsborough, occupying a stratum of four to six inches
in thickness, and covering an area of several acres. It remained
unchanged by sulphuric, hydrochloric, and nitric acids, and by heat,
and was concluded to be pure silica in a state of extremely minute sub-
division. On submitting it to the highest power of the compound mi-
croscope, it was found to consist of a mass of transparent squares and
parallelograms of different relative proportions, whose edges were per-
fectly sharp and smooth, and the areas often traced with very delicate
parallel lines. On comparing these with the forms of some existing
Confervce of the tribe DiatomacecB, which are parasitical on other Algoe
both marine and fresh water, but so minute as to be individually invi-
sible to the naked eye, the resemblance was found to be so strong as to
leave no doubt of their close alliance, if not perfect identity. To en-
able the Section to judge for themselves, Mr. Bowman exhibited highly
magnified drawings of some living species from the works of Dr. Gre-
ville, and also of the powder, which fully bore out the conclusion he
had arrived at. They are therefore the counterparts of the fossil infu-

72 REPORT — 1839.

soria of Ehrenberg, and occupy the same place in the vegetable king-
dom as those do in the animal.

On the Carboniferous and Devonian Systems of Westphalia. By
R. I. MuRCHisoN, Esq. F.R.S., F.G.S., ^c, and General Secre-
tary of the British Association.

The author states that having in company with Prof. Sedgwick ex-
amined the older rocks of N. Western Germany and Belgium, it is the
intention of his friend and himself to lay before the Geological Society
of London a general memoir (illustrated by numerous fossils) on the
classification of these ancient deposits, showing a succession of the Car-
boniferous, Devonian (or old red,) and Silurian systems.

The present communication bears chiefly upon one point of this
analysis, and is offered as a collateral proof of the geological position
of the culm-bearing strata of Devonshire and Cornwall, as stated by
Professor Sedgwick and Mr. Murchison to the British Association in
the year 1836.

Transverse sections in descending order, from the productive coal-
field of Westphalia on the N.N.W. to the older zoic rocks on the S.S.E.
were explained ; and one from Dortmund by Schelke to the neighbour-
hood of Linburgh and Iserlohn was specially adduced, in which the
various strata are exposed in fine natural sections in the following de-
scending order.

1. Coal shales, coal, &c. (productive coal-field.)

2. Millstone grit series, with many impressions of large plants, and
occasional thin seams of coal.

3. Thinly laminated arenaceous sandstones and shales, containing
many grasses and small plants.

4. Flat-bedded, black, bituminous limestone and shale, charged with
PosidonicB and Goniatites, and alternating with courses of flinty schist,
the kiesel-schiefer of German geologists. This band, identical in all
respects with the black or culm limestones of Devonshire described by
Professor Sedgwick and the author, is proved to be of the age of the
carboniferous or mountain limestone by containing at its western end
near Ratingen numerous well-known fossils of that formation.

5. Devonian rocks : — the old red sandstone, consisting of psammites,
schists, and limestones of great thickness containing many of those
peculiar fossils of Devonshire which first led Mr. Lonsdale to suggest
to Mr. Murchison {vide Geol. Proceedings, 1839-40) that they would
prove to be of the age of the old red sandstone.

6. Silurian rocks, &c., which rise up into mountain masses from be-
neath the overlying deposits*.

* The author has corrected the abstract so as to make it agree with the views
adopted by Professor Sedgwick and himself after their last visit to Westphalia,
subsequent to the Birmingham Meeting.

TRANSACTIONS OF THE SECTIONS. 7-^

The order and sequence of these strata are indicated and maintained
along the lower edge of the range of the large coal-field of Westphalia,
the beds successively rising to the surface at angles varying from 30°
to 40° in perfect conformity, and showing throughout the clearest and
most complete transition into each other. It is particularly to the
group No. 3 that the author directs the attention of British geologists,
because it is in all respects identical with the culm-bearing strata of
North Devon and Cornwall, first described by Professor Sedgwick
and himself as being a portion of a true coal-field, and not belonging
to the grauwacke or older transition rocks, to which they had formerly
been referred*. The Westphalian sections establish the geological
position of the culm strata of Devon and Cornwall more cleai'ly than
had been done by any stratigraphical evidence in Great Britain, by
presenting masses of mountain limestone and Devonian rocks rising
out from beneath the culmiferous schists, and thus the precise age of
the latter is demonstrated.

A General Outline of the Geology of Warwickshire, and a Notice of
some neio Organic Remains of Saurians and Sauroid Fishes belong-
ing to the New Red Sandstone. By G. Lloyd, M.D., F.G.S.

Dr. Lloyd briefly described, with the assistance of a coloured map
of the county, and a section extending N.W. and S.E. from Birming-
ham to Chesterton, the general distribution of the coal of North War-
wickshire, the new red sandstone, the lias, and the oolitic outliers in
the southern part of the county.

The coal-field, he observed, extends from Tamworth in a direction
N.N.W. and S.S.E. to Griff, where it is bent in a line nearly due south,
and terminates at Wyken; whence it is evident that this coal-field has
a double axis. The coal strata are thrown up at a highly inclined an-
gle, with a westerly and south-westerly dip, by the protrusion of thick
masses, sometimes preserving their lines of beddings of quartz rock
(altered Caradoc sandstone) and greenstone, on the eastern edge of the
field. The quartz rock, formerly described as millstone grit, of Harts-
hill and Tuttlehill, is extensively quarried for roadstones, and for the
manganese with which it abounds. No organic remains have yet been
observed.

The coal-measures were probably elevated during the deposition of
the lower new red sandstone, but anterior to that of the middle and
upper members, as is shown by the undisturbed sandstones and marls
of Attleborough and Marston. It is probable that this coal is con-
nected with that of Charnwood Forest rather than with the great field
of South Staffordshire, there being evidence of rapid thinning out on

* See Report of the British Association for 1836.

74 REPORT— 1839.

the eastern edge of the latter field. At Stockingford, near Nuneaton,
the " upper coal measures " make their appearance, containing a thin
freshwater limestone Math coal plants and traces of galena.

The lower new red sandstone is but slightly represented in this
county, the magnesian limestone and conglomerates nowhere observed.
The northern and central portions of the county are occupied chiefly
by the variegated sandstone of great thickness, and the variegated marl
also fully developed in some localities, in others it is extremely reduced.
The surface generally is much covered by northern drift and local
gravel. There is great diflSculty in determining the precise limits be-
tween the variegated sandstone and variegated marl, from the absence
of the muschelkalk. A thin bed, not more than two or three feet in
thickness, of highly calcareous, extremely hard, almost crystalline, white
marl, but containing no organic remains, occurs at Garrison Hill on the
Birmingham and London railway, but which, from its very limited ex-
tent and the absence of the characteristic remains, does not perhaps
deserve the appellation of an humble representative of muschelkalk. In
the variegated sandstone at AUesley near Coventry a part of the trunk
of a large coniferous tree about two feet in diameter has been exposed,
and eight or ten feet removed. The structure of the wood is identical
with the driftwood which abounds in the gravel of the neighbourhood.
The only animal remains yet observed in this part of the new red sy-
stem is a broken jaw of a sauroid fish, containing fifteen teeth, found
near Coventry. A considerable thickness of light-coloured sandstone,
thick-bedded, with nodules of green marl occasionally interspersed,
occurs at Warwick and Leamington, and extends, with occasional in-
terruptions, to the north-east as far as Attleborough ; some beds are
very hard, containing much carbonate of lime. The saline springs of
Leamington are in this sandstone, and small portions of rock-salt have
been found in it. The sandstone is observed in some localities, as near
Leamington, to pass gradually into the variegated marl ; and it is as-
serted that it does not range uninterruptedly over large tracts, but oc-
curs in wedge-shaped masses, thinning out in the strike and dip into
the marls. The thickness of the variegated marl intervening between
the sandstone at Leamington and the lias is less than 100 feet. In the
variegated marl at Shrewley Common, about five miles west of War-
wick, is a thin-bedded sandstone, hard, calcareous, white, sometimes
veined and mottled with red, and has been exposed to the depth of
thirty feet, including the interbedded red and green marl. This stone,
which Mr. Murchison and Mr. Strickland consider is the true keuper
sandstone, is, like the Warwick sandstone, of local appearance, though of
frequent occurrence in the same parallel, and passes into the marl.
Footsteps of a Batrachian(?) reptile were discovered by Mr. Strickland
two years since in this stone. No organic remains have yet been found
in it excepting Posidonomya minuta, (a shell common to the keuper
and variegated sandstone,) and a few indistinct fragments of reptilian
bones. Ripple and worm marks are frequently observed.

TRANSACTIONS OF THE SECTIONS. 75

On the Organic Remains of the Warwick Sandstone.

The author stated that remains of animal forms recently found at
Warwick and in the neighbourhood, apparently distinct from those of
the new red system of the Continent hitherto published, had been
submitted to Prof. Owen, who after minutely examining them had de-
scribed them in detail under the names of

Platygnathus rugosus, certainly of reptile organization.
Dolicognathus Lloydii, 1 , , , • i fi Vi

Dolicognathus varvicensis, j " J

Crenated teeth of a large saurian, an episternal piece of Phytosaurus,
and coprolites of various forms have been found in the same loca-
lities.

On Fossil Fishes from St. George's Collierg near Manchester.
By Mr. Binney.

On the Foot-prints and Ripple-marhs of the New Red Sandstone of
Grinshill Hill, Shropshire. By O. Ward, M.D.

The stratum in which these impressions are found consists of a finely
laminated buff-coloured flagstone, from five to ten yards thick, overlaid
by two yards of a rubbly corroded red sandstone called " Fee," and un-
derlaid by twenty yards of a buff-coloured massive building-stone,
which rests upon a red sandstone of unknown thickness at the base of
the hill. The ripple-marks are of three kinds : fine ones with sharp
edges ; wave-marks, more or less continuous elevations and depressions
with smooth rounded surfaces ; and little stream-marks. Foot-prints
and rain-drops only found on the ripple- and wave-marks. The rain-
marks are not always perpendicular to the general surface, but appear
to have struck forcibly against the opposing face of a wave-mark,
while they have glanced off from the sloping side ; thus indicating the
direction of the wind at the moment of formation. The foot-marks
differ from those of the Cheirotherium in having only three toes, armed
with long nails, directed forwards, not spreading out, and one hind toe
on the same side as the longest fore toe, pointing backwards, and hav-
ing a very long claw. No impression of the ball of the foot in this ex-
ample ; but in another there are three toes, and a depression for the
ball not unlike that of a dog. The foot-prints and ripple-marks were
made upon a surface alternately wet and dry, probably on the shore of
a sea or tidal river, dry land being near, of which this hill formed the
beach. The strata take the slope of the hill northwards, and the

76 REPORT— 1839.

streamlets flowed in the same direction. From the gradual passage of
flag-stone into the massive building-stone, it is argued that the former
has never been under much pressure in the upper part, and therefore
has always maintained nearly the same distance from the surface that
it now has.

On the Action of Acidulated Waters on the surface of the Chalk near
Gravesend. By the Rev. W, Buckland, D.D.,F.R.S.,F.G.S., ^c.

The author first adverted to the frequency of caves in connexion
with fissures in the limestone rocks of all countries ; and considered
the enlargement of many fissures into caverns to be due to the cor-
roding action of acidulated vapours and waters. He cited a remark-
able example of a very lofty dome-shaped cavern at Pantalica, near
Syracuse, which he considered to have been produced in this manner.

He also attributed to the corroding action of water charged with
carbonic acid, the origin of the deep irregular furrows, pits, and gul-
lies which are so frequently found on the surface of the chalk, and are
usually filled with gravel mixed with clay and sand ; and cited exam-
ples of excavations of this kind in deep sections of the chalk hills by
the road-side between Beaconsfield and High Wycombe, and at the top
of the hill immediately east of Henley in Oxfordshire. He refers to
the epoch of the plastic clay formation the gravel and clay filling these
cavities near Beaconsfield. Here remains of tortoises were found in
the clay by the late Lord Grenville.

About ten years ago a remarkable opportunity occurred at Graves-
end of seeing a large surface of chalk stripped of its covering of sand
and gravel, and exposing the condition it had acquired before the ar-
rival of this covering, which was removed in order to get access to
the chalk. Before the deposition of this sand, in which were many
bones of deer and other mammals, a shallow bason, about twenty-five
feet deep, and extending over a quarter of an acre, appears to have
been formed on the surface of the chalk; the entire bottom of this
bason presented a surface covered with irregular bowl-shaped cavities,
separated from one another by intermediate rounded hillocks and
ridges, resembling the little pits and ridges that appear on the surface
of a piece of limestone that has been steeped in acid. Most of these
cavities were about three feet in diameter, and their depth varying
from one to two feet. Both the elevated and depressed portions of the
chalk had the same smooth and somewhat glossy surface that compact
limestone presents after corrosion by an acid.

Dl". Buckland referred all these phaenomena to the action of acidu-
lated waters, and was of opinion that the frequent volcanic eruptions
during the tertiary period might have impregnated the sea in certain
regions with carbonic acid, which would account for the extensive cor-
rosion and destruction which the chalk underwent at that epoch, when

TRANSACTIONS OF THE SECTIONS. *]*]

the gravel-beds of the eocene period were supplied with flints, set free
by the solution of the chalk in which they had been formed, and sub-
sequently rounded by the action of water. He considered also that the
carbonic acid contained in rain-water has produced in more recent
periods, and still continues to produce similar effects in corroding and
forming cavities on the surface of chalk beneath permeable beds of
gravel or sand.

Exact and beautiful drawings of these appearances at Gravesend
were made at the time of their discovery by Mr. Thomas Webster, for
Dr. Buckland, and were exhibited at the Section to illustrate his ob-
servations.

On an ceconomical Use of the Granitic Sandstone of North Staffordshire.
By Robert Garner, Esq., F.L.S.

This paper announces the recent discovery of a valuable property in
a substance hitherto esteemed worthless. Previously to the last three
or four years it has been the practice to import chalk-flints at a great
expense into North Staffordshire, for the use of the earthenware ma-
nufacture. It has been lately found that the millstone-grit of the Pot-
tery district will answer the same purpose, and it is now quarried to
the extent of many hundred tons annually. It is found to be a perfect
substitute for flint, with the advantage of not requiring calcination pre-
viously to being ground. The material for the pottery is compounded
of about equal parts of millstone-grit, Dorsetshire and Cornwall clay,
and the ware produced is found to possess the qualities of whiteness
and compactness in a high degree. The best specimens of millstone-
grit are those which contain about three parts of silica and one of alu-
mina, and which are free from iron or sulphate of barytes.

On the rapid Changes which take place at the Entrance of the river
Mersey, and the means adopted for establishing an easy access to
Vessels resorting thereto. By Jos. Brooks Yates, Esq.

The author commences this paper with an historical sketch of the
changes which have taken place at various times in the sestuary of the
Mersey. It appears that at some distant period this sestuary was
principally occupied by peat mosses and forests, vestiges of which are
still found beneath the sands on the coasts both of Cheshire and Lan-
cashire. These mosses appear to have been submerged by an irruption
of the sea, which has encroached so much on the land within the last
few years as to require the erection of a sea-wall to protect the Leasow
lighthouse.

The changes in the submarine sand-banks are shown by a comparison
of ancient with modern charts. From a survey made in 1687 by Capt.
Grenville Collins, it appears that large ships were obliged to unload

78 REPORT — 1839.

part of their cargo before they could come up to Liverpool, which at
that time was inferior to Chester in importance. The entrance has
since become deeper, and a channel called "Helbre Swash" has been
formed across the " Hyle sand," which in 1687 was dry at high water
of the neap tides. Many similar changes are shown to have taken
place, but the most important is one which is now in progress by hu-
man agency. This is a new channel, about one third of a mile wide
and thi'ee quarters of a mile long, which has already been deepened
upwards of four feet, and will shortly be thrown open to shipping
under the name of the Victoria channel. The deepening is eifected by
dragging a large iron harrow, invented by Lieut. Lord, over the sand-
bank by means of a steam- vessel. This process is continued daily dur-
ing the ebb tide, and the sand and mud thus loosened from the bottom
is carried out to sea by the current. The complete success of this
invention recommends it to the notice of persons connected with other
harbours.

On Peat Bogs. By G. H. Adams, M.D,

Prof. Shepard, of Yale College, exhibited a collection of organic
remains from the limestones of North America, numbered ; many of
the specimens corresponding to the numbers towards one end of the
series, belonging certainly to species described in Mr. Murchison's
work on the Silurian System ; many of those toward the other end
as certainly identical with species figured by Professor Phillips in his
work on the Geology of Yorkshire.

ZOOLOGY AND BOTANY.

On the Formation of Woody Tissue. By Mr. Edwin Lankester.

The tissues of plants, for the sake of convenience, are divided into
five, the origin of which may be all traced to the simple cell. How
they are formed, is an undecided qviestion, more especially with re-
gard to woody tissue. Du Petit Thouars supposes that woody fibre
is formed by the buds and leaves, and sent down by them between the
bark and wood, where they are nourished by the cambium. Others
suppose that it is formed from the wood or bark. The most promi-
nent features of woody tissue are its length, and hardness from the
deposit of secretions in its interior. These points, however, do not
constitute an essential difference between woody and cellular tissue,
as we find the latter lengthened in the form now called Pitted tissue,
or Vasiform tissue, and hardened d^s, in the endocarps oi Amygdalece, &c.

If in the term woody tissue all lengthened, hardened tissue be in-

TRANSACTIONS OF THE SECTIONS. 'J9

eluded, then we find it present in many instances where neither buds,
leaves, or bark, can be said to exist, as in Cryptogamic plants, especially
various species of jBoleti. It is also found in many parts of Phanero-
gamous plants, as the pericarps of the cocoa, beech, and other plants
which in those parts are destitute of leaves. The author had also
found woody tissue in abundance in the leafless Monotropa, and in
many species of Cactacece.

Another objection to the theory of Du Petit Thouars is found in
the fact of wounds of trees filling up at the lower as well as the upper
lip. In trees that had been felled, the author had observed the pro-
duction of fibrous tissue independent of leaves or buds, (specimens of
this were exhibited to the Section).

The author then detailed some experiments he had made by ringing
beech trees in the spring of the year. When cut down in August, a
cellular and woody formation appeared both in the upper and lower
lips of the wounds, the woody tissue having been formed subsequent
to the ringing.

The last occurrence to which the author directed attention, and
which could not be explained by this theory, was the existence
of knobs of wood in the bark of beech and other trees. These
excrescences are of all sizes, and when first formed, are cellular;
they gradually harden, and at last present layers of contorted woody
fibre. They have a regular bark of their own, filled with sap during
the spring, and present, when cut, concentric circles of woody
tissue representing their yearly growth. Many of them put forth
buds, and some few of them leaves, but by far the greater number have
neither buds nor leaves. Sometimes several are found together in a
mass (especially in the elm and acacia), each nucleus having a sepa-
rate series of concentric layers surrounding it. Although, from rapid
growth, the compound knobs are found in contact with the wood of
the tree, the single knobs are seldom found in this position. These
knobs have been called by Dutrochet embryo buds. The conclusions
which the author advanced, from his present knowledge of the facts,
were,

1st. That the requisites for the formation of wood are, 1. a living
tissue developing elongated fibres ; 2. a tissue forming and depositing
secreted matter ; and 3. exposure to the influence of external stimuli.

2nd. That the secreted matters are more easily brought under the
influence of external stimuli in the younger tissues ; hence the import-
ance of leaves.

3rd. That neither bark nor leaves are essential to the formation of
woody fibre.

Notice of Zoological Researches in Orkney and Shetland during the month
of June 1839. By Edward Forbes and John Goods ir, Esquires.

During their short excursion, the authors directed their attention
almost exclusively to the invertebrate animals. Of mollusca, they

80 REPORT— 1839.

found five species of the genus Eolida. Of these, four were unde-
scribed, the other being Eolida papillosa of authors, which abounded
in Shetland, under stones at half tide, whither it appeared to resort for
the purpose of spawning. The four new species are named by the
authors E. Zetlandica, E. coronata, E. foliata, E. minima ; the two
last were obtained by dredging in seven fathoms' water. They found
no Eolidae in Orkney.

Of the genus Euplocamus they found one species, allied to the
Euplocamus pulcher {Triopa clavigera of Johnston), but differing
from that species, in having its branchiae, both lateral and dorsal,
tipped with yellow. Its back is white, spotted with yellow. Of the
genus Doris they found two species, one the Doris pilosa of MUUer,
and the other Doris hervicensis of Johnston.

They found one new testaceous mollusk, a species of Velutina,
which the authors have named Velutina elongata. Ascidiae abound in
the north ; the more common species is the Ascidia intestinalis. Along
with it they found three species, which, there is reason to believe, are
undescribed. The authors propose to name them Ascidia echinata,
Ascidia rugosa, Ascidia rubens, the two latter are from Orkney. Of
Annelides the authors found great numbers ; such as they collected
they intend submitting to Dr. Johnston, as the highest British authority
on that class. They observed Planariee in great numbers : among
others was the beautiful Planaria atomata of Miiller, not before re-
corded as British. Among the Radiate animals they were especially
successful. The genus Holothuria is conspicuous in Shetland ; among
them is an enormous species, which the authors name Holothuria
grandis. This splendid animal is fully two feet long, when extended ;
it is of a deep purple colour ; it has ten triangular frondose tentacula,
purple, spotted with white ; its body, between the rows of suckers, is
almost smooth. The other new species of this genus observed were —
Holothuria fucicola, Shetland, Holothuria brevis, Holothuria fusif or mis,
Holothuria lactea, Holothuria pellucida of Miiller. Along with Holo-
thurise the authors dredged the Priapulus caudatus, and Sipunculus
strombi. They found no Holothurise or Priapuli in Orkney.

Of the sea-urchins they found only the Echinus esculentus, and a
form which appeared to be the Echinus neglectus of Lamarck. The
star-fishes observed were Asterias aranciaca, and an allied form, pro-
bably the Asterias bispinosa of Otto, Stellonice rubens and violacea,
Luidia fragilissima, Solaster papposa, Ophiura albida and texturata,
Ophiocoma bellis, granulata, rosula, neglecta, and a new species. The
Medusae doubtless abound in these islands in August, their proper
season ; but when the authors of the paper were there, they observed
only Cyancea capillata, Medusa aurita, a new Dianaea, a new Oceanea,
a new Ciliograde, of the genus Alcynoe of Rang, and a minute ani-
mal, the type of a new genus among the Acalephae. Sponges of the
genera Grantia and Holochondria abound in Shetland. From deep
water the authors obtained several specimens of Tethya cranium, and
kept them alive in salt water, but could observe none of the contrac-
tions stated to have been seen in that species by some of the French
naturalists.

TRANSACTIONS OF THE SECTIONS. 81

The most beautiful contribution to the British Fauna from the Ork-
neys, is a zoophj'te of the family Tubulariadae, the largest known form of
its tribe. This beautiful animal is about four inches long, and its stem half
an inch in diameter. This stem is rounded, solid, flexible, moving at the
will of the animal, and somewhat contractile. It is translucent, of a pink-
ish-white colour, lineated with brown longitudinal lines, arranged in pairs.
When young, the stem is shorter, and is inclosed in a delicate, brown,
corneous tube, which becomes deciduous as the animal grows larger.
The lower part of the stem is broader than the upper, and roots in
sand by means of a fusiform termination, sending out corneous fila-
mentous roots. At the upper extremity the stem becomes suddenly
contracted, and the lines terminate ; it then expands into an ovate
head, terminating in a long, pyramidal, pink trunk, at the end of which
is the mouth. Round the thickest part of the head is placed a row of
about forty long, white, uncontractile tentacula, which wave about in
all directions, and are not ciliated. Immediately above the circle of
tentacula is a circle of about twenty-five ramified orange processes,
probably ovarian, having no voluntary motion. Above this the trunk
is covered with numerous white tentacula, very much shorter than the
outer circle. Within this head is a simple digestive cavity, not ex-
tending down so far as the large tentacula. Every other part of the
animal is solid, and no part is ciliated. Beautiful and delicate as these
animals appear, they are very tenacious of life. They were dredged in
considerable numbers, on a sandy bottom, in about ten fathoms' water,
at Stromness, Orkney. The position of this animal is between Tubu-
laria and Coryne, on the relations of which genera its discovery throws
much light, as well as on the polypes in general. The authors pro-
pose to consecrate the genus to that great British zoophytist, Ellis,
calling it EUisia, and giving the species the appropriate name of Flos
maris, as it may well be regarded, from its extreme grace and beauty,
as the flower of the British seas. The relations of EUisia to Tubularia
may be exhibited by the following diagram : —

Coryne

Note. — The EUisia has since proved identical with the Corymorpha nutana
of Sars.

1839. G

I REPORT — 1839.

Coryne — Tentacula scattered, of one kind ; no tube.
Hermione — Tentacula scattered, of one kind ; tube.
Eudendrium — Tentacula of one sort, regular ; branched tube.
Tubularia — Tentacula of two sorts, regular ; simple tube.
Ellisia — Tentacula of two sorts, regular ; deciduous tube.

Mr. W. R. Wilde exhibited three drawings of a Peruvian mummy,
showing its different states of development.

Mr. Lankester made some observations on the preparation of fishes
for museums. He exhibited several specimens, which, after having
taken aAvay one side, he had allowed to dry, and assume their natural
state, and then placed them on paper. The process consisted in dry-
ing the fish, then taking away their soft parts, then drying the skins,
keeping them in shape by pieces of stick and cork, and, finally, var-
nishing them with mastic varnish, by which they become stiffened,
and their colours preserved.

On the Follicular Stage of Dentition in the Ruminants, with some
Remarks on that Process in the other Orders of Mammalia. By
John Goodsir, Esq.

Mr. Goodsir commenced by stating, that since the last Meeting he
had detected the follicular stage of dentition in the pig, rabbit, cow,
and sheep, but that he had not had an opportunity of examining it in
those animals in which observations would have been most valuable.
He had been able to verify, what at that time he stated as probable,
viz. that all the permanent teeth, with the exception of the first molar,
which does not succeed a milk tooth, are developed from the internal
surface of cavities of reserve, and that the depending folds of the sacs
of composite teeth are formed by the lips of the follicles advancing
inwards, after closure of the latter. He then described the progress
of development of the pulps and sacs of the teeth in the cow and
sheep, from their first appearance, as minute as possible, on the full
surface of the membrane of the mouth, or on the internal surface of
the cavities of reserve, till they have acquired their ultimate configu-
ration. In the course of this description he announced the fact, that
at an early period of the embryonic life of these animals, they possess
the germs of canine and superior incisive teeth ; the former existing as
developed organs in two or three genera only of ruminants, the latter
being found in the aberrant family of camels. Mr. Goodsir stated,
that these germs presented themselves under the form of slight dimples
in the primitive groove, and that after the closure of the latter, they
remain for a short time opaque nodules imbedded in the gum, in the
course of the line of adhesion. The existence of germs of canines and
superior incisors in the cow and sheep is highly interesting, as it shows
l»ow general the law of unity of type is within certain limits. Geof-
froy St. Hilaire was the first to announce the existence of tooth germs

TRANSACTIONS OF THE SECTIONS. S3

in the foetus of the Balcena Mysticetus, a fact which has been verified
by Dr. and Mr. Frederic Knox, in whose museum there is a prepara-
tion exhibiting the germs under the form of sacs and pulps. Although
the germs never arrive at this stage of perfection in the cow and
sheep, they are yet distinct enough to indicate their existence ; and
the author of this paper has no doubt, that when the embryos of other
partially or wholly edentulous mammals have been examined, similar
results will be obtained. The author then proceeded to state, that the
peculiar maimer in which the sac of a ruminant molar, and probably
of every other composite tooth, is formed, may be best seen in longi-
tudinal or transverse sections of the sac and pulp of the fourth per-
manent molar of the sheep or cow. The internal surface of the cavity
of reserve is seen to end in a fold or folds ; when these meet, they
begin to curve towards the papilla, and to enter parallel to one another
the cavity or notch which is simultaneously forming in the latter. As
soon as the edges of the folds meet, the granular matter denominated
enamel pulp by Hunter (the formation of which was described by
Mr. Goodsir in the human embryo, at the last Meeting of the Associa-
tion,) begins to be deposited, cementing together the opposing folds,
sealing up the new sac, separating it from the rest of the cavity of
reserve, filling up the space existing between the pulp and sac, and
ultimately assisting in the formation of the depending folds of the
latter. The author then referred to the distinction which must be
draw^n between those permanent teeth, which are developed from the
primitive, and those which are developed from the secondary groove ;
and stated that he had been in the habit of dividing the teeth of these
animals, the dentition of which he had examined, into three classes ;
viz. 1. Milk or primitive teeth, developed in a primitive groove, and
deciduous. 2. Transition teeth, developed in a primitive groove, but
permanent. 3. Secondary teeth, developed in a secondary groove, and
permanent. Mr. Goodsir expressed a hope that other anatomists would
verify and extend this line of research, as the results appeared to him
not only confirmatory of certain great general laws of organization,
but as leading, in his opinion, by the only legitimate path, to the deter-
mination of the organic system to which the teeth belong, (a subject
exciting great interest at present,) and as it might enable us, in inves-
tigating the relations of dental tissue to true bone, to avoid the error
of confounding what there appears to be a tendency to do, analogy
with affinity. The paper concluded with a recapitulation of the prin-
cipal facts contained in it. 1 . In all the mammalia examined, the fol-
licular stage of dentition was observed. 2. The pulps and sacs of all
the permanent teeth of the cow and sheep, with the exception of the
fourth molar, are formed from the minor surfaces of cavities of reserve.

3. The depending folds of the sacs of composite teeth are formed by
the folding in of the edges of the follicle towards the base of the con-
tained pulp, the granular body assisting in the formation of these folds.

4. The cow and sheep (and probably all the other ruminants,) possess
the germs of canines and superior incisives at an early period of their
embryonic existence.

84 REPORT— 1839.

On the Preparation of Fish. By Mr. Wilde.

In this mode of preparation an incision is made through the scales
to the muscles, commencing about where the operculum joins the
cranium, and continuing it parallel with the dorsal outline to the centre
of the tail. A similar cut is made from above the pectoral fin, till it
also reaches the centre of the tail ; by this means somewhat less than
a third of the side is included between the lines. The fish is kept
steady on a smooth board, adhering to it by the natural gluten, water
being poured over it from time to time, so as never to allow the scales
to dry. The skin is then dissected back as far as the dorsal margin,
where it meets the bony rays which support the fins. These are cut
across, as close to the skin as possible, Avith a strong pair of scissors or
a cutting forceps. A similar process is used towards the abdomen,
taking care to keep as close to the fascia to which the scales are
attached as possible. The first vertebra is then divided from the
cranium, and the skinning process continued by lifting up the body
and leaving the skin adherent to the board, from which it should never
be removed, if possible, till the dissection is completed. Diflficulty
Avill be experienced towards the tail, where the muscles become more
tendinous, and are attached to the subcutaneous fascia. The rays of
the caudal fin are then divided from the vertebra, and the body
removed entire. The gills are next taken out, and the flesh of the
cheeks and any remaining portion about the head or thorax. It is as
well, perhaps, to leave in the scapula, or a large portion of them. An
opening is made into the side of the cranium, whei^e it will be found
very thin, and the brain taken out. The eye is completely removed on
the reverse side ; a hook, passed down through the orbit, transfixes the
back of the sclerotic of the other eye, in which an opening is made ;
the finger then pressed on the cornea in front will squeeze out the lens
and humours, retaining the iris perfect in its place, and the author has
lately succeeded in retaining the gills, if necessary ; the tongue is left
in, and the fish is then cleansed from all impurities, taking care not to
stretch the skin nor to injure the scales. It is next dried, and either
well anointed with arsenical preparation or the spirituous solution of
corrosive sublimate. The eye is filled with cotton from the opening
in the back ; care being taken to keep the iris in its natural position.
The cranium is also stuffed; and flakes of tow, cotton, or any material
of light description, laid along the body till a sufl[iciency to give the
form of the animal is put in. The reflected edges are then returned ;
the fish is removed from the board, and placed with the front up ; the
tail and fins, expanded, are pinned down in their natural position, on
cards, supported by little bits of cork ; the fish is given its proper
shape, and the inequalities on its surface smoothened off with a soft
brush ; it is then set to dry in a current of cool air, with little sun, and
should be watched to see that it dries equally, and that no part of the
skin shrinks more than another. If it should, a brush, wetted in cold
water, touched upon the part, will restore it. It should be varnished
the moment it is sufficiently dry, and the cards, &c., removed from the

TRANSACTIONS OF THE SECTIONS. 85

fins, which will now retain their natural position. Common copal
varnish, diluted with turpentine, is recommended as the best. The
cornea now becomes hard, transparent, and continuous with the sur-
rounding skin : the wadding may be removed through the back of the
sclerotic, and a bit of foil introduced in its place, of the colour
originally possessed by the animal, in many of which we know the
tapetum is very brilhant. The author noticed the difficulties which
attach to this process in fishes with small scales, and described the
methods by which they were overcome.

Mr. R. Patterson exhibited drawings made from living specimens of
a species of Ciliograde, taken in July last at Bangor, County Down.
Its occurrence on the Irish coast had first been announced in a note
a])pended to his paper on the Cydippe pomiformis, published in the
Transactions of the Irish Academy. This animal he had referred,
though with some doubt, to the genus Bolina, of Mertens, and named
it provisionally Bolina Hihernica. He mentioned some particulars
relative to its appearance, movements, frangibility, and luminosity.

O71 the Ciliograda of the British Seas. By Edward Forbes, and
John Goodsir, Esqrs.
The Ciliograda of the British seat belong to three genera — Cydippe,
Alcynoe, and Beroe. The genera and species may be summed up as
follows : —

Ciliograda.

Genus I. Cydippe, Esch. — Animal provided with filamentary ap-
pendages, but without natatory lobes or oral tentacula.

Genus II. Alcinoe, Rang. — Animal not provided with filamentary
appendages, but furnished with natatory lobes and oral tentacula.

Genus III. Beroi^, Linn. — Animal unprovided with filamentarj'^ ap-
pendages, natatory lobes, or tentacula.

I. Cydippe, Eschscholtz. (Pleurobrachia, Fleming.)

1. Cydippe pileus (Linnaeus) — Rows of cilia, 19 or 20, on the
summits of the lobes. Filamentary appendages white. St. Andrew's.
Mouth of Thames. (Dr. Grant.)

2. Cydippe Flemingii (Forbes), (a BeroU ovatus, Fleming ?).
Rows of cilia 36, on the summits of the lobes. Filamentary append-
ages white. St. Andrew's.

3. Cydippe lagena (Forbes) — Rows of cilia about 25, placed in
the furrows of the lobes. Filaments white. Coast of Ireland.

4. Cydippe pomiformis (Patterson) — Rows of cilia about 20. Fila-
ments rufous. Coast of Ireland and Mouth of Forth.

II. Alcinoe, Rang.

2. Alcinoe rotunda (Forbes and Goodsir). — Ovate, rounded, cry-
stalline ; tentacula rounded at their extremities. Natatory iobes form-
ing half the animal. Kirkwall Bay, Orkney.

86 REPORT— 1839.

2. Alcinoe Smithii (Forbes). — Elongato-pyriform, subcompressed,
crystalline. Natatory lobes not more than a third of the whole length
of the animal. Tentacula acute. Near Ailsa Craig and Irish coast.

III. BERoii, Linnasus.

1 . Beroe cucumis (Otho Fabricius). — No spots on external surface,
internal dotted with red points, ciliiferous ridges red.

2. Beroe fulgens (Macartney).

On some new Species of Entozoa, discovered by Dr. Bellingham.

On the Acceleration of the Growth of WJieat. By Geo. Webb
Hall, Esq.

The object of Mr. Hall's communication was, to call the attention
of the Meeting to a statement of facts connected with the acceleration
of the growth of Avheat, and a consequent diminution of the period
required for its occupation of the ground, and to exhibit the results of
the proceeding, and the benefit deducible therefrom. The ordinary
period of growth allotted to the wheat plant may be taken from the
middle of October to the middle of August — a period of ten months —
twelve, or even thirteen, being not uncommon : while for the ordinary
winter wheat, from December to August may be taken as the shortest
period of growth : close observation of the progress of the plant, under
different circumstances, and a peculiar selection of seed from warm
soils, have reduced this period to nearly five months. An abundant
crop of wheat, which was sown on the 2nd of March, was ready for
the sickle on the 15th of August following. This is not a solitary
case, nor is it the result of a peculiar season. In the year 1835, wheat
sown on the 5th of March was reaped on the 12th of August ; and on a
previous occasion, wheat sown on the 9th of March was reaped on the
11th of August, the produce being forty bushels per acre. A deep
tenacious soil is most congenial to the growth of wheat ; such soils,
however, form a very minute portion of the land of England ; to the
lighter and more siliceous soils Mr. Hall's observations apply. When
wheat is placed upon the lighter soils, its growth and security are alike
promoted by artificial pressure and compacting of such soils, which
also, by the addition of manure, acquire a warm and stimulating cha-
racter ; but they as assuredly become quickly exhausted, and therefore
the acceleration of the growth and ripening of the plants committed
to a light soil, and a diminution of the time required for perfecting its
crops, is congenial to its character, and tends to economize and pro-
long its productive powers. Mr. Hall wished to direct the attention of
botanists to the practicability of so adapting the seed to the soil, and
regulating the time of sowing, that an early ripe crop should be always
obtained, and the accidents be avoided on a large pi-oportion of our soils
to which a growing crop is exposed in the depth of winter.

TRANSACTIONS OF THE SECTIONS. 8?

Notice of an Experiment on the Grotvth of Silk at Nottingham in
1839. By William Felkin, Esq.

A large sample of yellow and pure white cocoons, forming a portion
of the results of this attempt at raising silk in England, was placed
before the Section of Natural History, upon the twigs where they had
been spun by the silk worms,— the French and Italian mode of manage-
ment being, so far as possible, adopted throughout the entire course of
the experiment. Bertizen produced equally good cocoons somewhere
near London, in 1790, but beyond his presenting the silk reeled from
them to the Society of Arts, and receiving their premium, only few
particulars of his experiment are known. In the present instance, the
food supplied to the worms spinning the white silk (owing to the
sudden and continued check to vegetation by severe east winds and
frosts throughout May 1839,) was lettuce leaves during the first three
weeks after hatching, afterwards they were fed entirely upon mulberry
leaves. Those spinning yellow silk were hatched fourteen days later,
and were fed from the beginning upon mulberry leaves. Of those
fed partly upon lettuce, 7-8ths died ; on the contrary, the greatest loss
in those fed altogether upon mulberry was from 30 to 40 per cent.
The average of loss upon the continent of Europe is from 35 to
60 per cent., the latter being the usual loss under the management of
the peasants. That division of these yellow ones which spun first,
and which were most healthy, experienced a loss of only 10 to 20 per
cent. The loss in China, owing to their superior skill and care, is
often not more than 1 per cent, of those hatched. The hatching in
question was of eggs procured fi-om Italy ; and this, as well as all the
subsequent processes of feeding and spinning, took place in a ware-
house in the centre of the town of Nottingham, amidst the usual noise,
dust, and activity of a wholesale business in cotton goods, where the
air must have been in some degree tainted by the oily matters used in
their fabrication. The weather for three weeks from the 14th of May
was dry, but piercingly cold ; then, after an interval of two weeks of
fine weather, there was constant and most unusual humidity, so that it
was almost impossible to refresh the air of the apartment, or avoid
giving the food in a damp and heated state ; especially as, from the
number of worms (about 10,000), much difficulty was expeiienced in
obtaining mulberry leaves in sufficient quantity for their use, these
having to be collected from places in some cases 50 or 80 miles di-
stant. Such was the continuance of rain in July, that the largest flood
occurred ever remembered at that season of the year. To suit our
variable climate the temperature of the room was from the first kept
low, varying from 70 to 55 degrees. Altogether, the circumstances
under which this experiment was made were very unpropitious.

In addition to the usual diseases which Mr. Felkin had observed,
when formerly investigating the French and Italian management of
silk worms, one occurred immediately after a violent storm of thunder,
lightning and rain, which was quite new to him. The worms were
nearly ready to spin, and those affected were found dead or dying ; the

88 REPORT— 1839.

^vrinkled part of the body to which the head is attached, quite black,
and the skin of the neck thickened and tough like leather. Again, as
the heavy and damp weather continued, a disease occurred, affecting
the two front and two hind rings of the body, by producing an
unnatural and evidently very painful contraction of the parts, and a
corresponding enlargement of the four middle rings, which usually
ended in the sac bursting, and of course destroying the insect. It may
be remarked, that the pulsation visible along the back of the Avorms
was, in the case of those fed upon lettuce, reduced to 20 and 25 beats
a minute : in order to ascertain whether this arose from the food, some
were fed with mulberry, while the rest were continued upon lettuce.
The former exhibited a daily increase in the pulsation of about 5
beats ; until, at the end of three or four days, the muscular expansion
and contraction along the back was of the usual quickness, i. e. 40 to
45 beats a minute ; which was what those fed entirely on mulberry
leaves invariably exhibited.

The time of spinning in Italy is usually six weeks after hatching.
In Nottingham the earliest did not spin until eight weeks after hatch-
ing ; but such as were originally fed upon lettuce did not spin until
those fed entirely on mulberry had finished their cocoons ; the lives of
the former were therefore protracted full three weeks beyond the
latter.

The cocoons being placed in contrast with those (also on the table
of the Section) of this year's growth, just received from the Milanese,
presented but slight inferiority in size, weight, or compact formation.
Of those grown in Nottingham, it took an average of 300 to weigh a
pound, while of the best French or Italian, it takes at least 250. The
English acclimated cocoons weighing, when dry, I to 1^ grains, fed
upon lettuce and mulberry ; those of Bengal, 1 to 2^ grains, fed on
Indian mulberry ; Italian, 3 to 6 grains, fed on white mulberry ; Not-
tingham, 2g- to 5 grains, fed on black mulberry ; New Jersey, U. S.,
two crops a- year, 5 grains ; and New Jersey, Mammoth, 6 to 8 grains,
(the last two fed on Morus multicaulis,) were exhibited to the
Section.

The chief object in view, in bestowing the time and labour neces-
sary to bring about the results which establish the interesting and
important fact, that silk of the best quality could thus be grown in
England, was to show how the produce of this article might be greatly
improved in quality, and indefinitely increased in quantity, in Hin-
doostan. There, labour is cheaper than anywhere besides ; and land
unoccupied and waste, but perfectly suitable for the mulberry, is plen-
tiful ; so that, by not confining the cultivation of silk to the marshy
Delta of the Ganges, as at present, but introducing into the more
elevated and even mountainous parts of Hindoostan, &c., the superior
kinds of silk worms and mulberry trees so long grown in the south of
Europe, and recently cultivated in the United States of North Ame-
rica, raw silk might be supplied from India at half its present cost — a
cost increased by the demand greatly exceeding the supply, so as to
have compelled us to pay four instead of three millions sterling a-year,

TRANSACTIONS OF THE SECTIONS. 89

during the last four years, for tlie same weight of material, and thus
greatly to limit the extent, and even to risk the safety of the silk
manufacture itself.

Some Observations on Whales, in connexion with the account of the
Remains of a Whale recently discovered at Durham. By George
T. Fox, Esq.

Among the rubbish in some crypts or cellars, beneath the old Tower
of Durham Castle, several large bones were found ; twenty vertebrae,
and about the same number of ribs, of enormous size were taken out ;
and in a crypt or room on the opposite side of the tower, two large jaw
bones were laid bare. This latter discovery enabled Mr. Fox to deter-
mine, from the form and position of the jaws, that the bones belonged
to a spermaceti whale. The discovery excited considerable interest in
the town. But while the inquiries, to which the circumstance had
given rise, were going on, the Rev. James Raine discovered a curious
and interesting letter, in a MS. volume of the late Mr. Surtees' collec-
tion, relative to the history of the Castle of Durham, which at once
accounted for the discovery of animal remains under such circum-
stances.

The letter is from John Cosin, Bishop of Durham, addressed to his
Secretary, Mr. Miles Stapylton, dated Pall Mall, London, June 20, 1661,
and clearly shows that the bones discovered in Durham Castle be-
longed to an animal cast on shore on the coast of Durham, at Earing-
ton, and the date (1661) proves it to be the oldest whale of the kind
recorded to have been found on the British coast. The remains of the
animal, when collected, were found to consist of twenty-six vertebrae,
fourteen ribs, and two lower jaws, of the great blunt-headed Cetodon
{Physeter macrocephalus).

On the Statistics of British Botany. By Mr. Brand.

This paper consisted chiefly of remarks on the Catalogues of Plants,
on which Mr. PI. C. Watson had founded his conclusions in his work
on the Geographical Distribution of the Plants of Great Britain. Proof
sheets of the Catalogue formed from this source were exhibited to the
Section. Also the proof sheet of a catalogue for arranging the Society's
General Herbarium.

On the Extinction of the Human Races. By Dr. Pritchard.
He expressed his regret that so little attention was given to Ethno-
graphy, or the natural history of the human race, while the opportuni-
ties for observation are every day passing away ; and concluded by an
appeal in favour of the Aborigines' Protection Society*.

Mr. J. E, Bowman exhibited specimens of a species of Dodder
* Sec in this Volume the Synopsis of Giants of Money at Biiiningham.

90 REPORT — 1839.

(^Cuscuta epilinum), first found in Britain, two years ago, by himself;
and again in a new locality, within the present month. Having noticed
the distinctions between this plant and C. Europcea, as well as C. epili-
num of Weihe, Mr. Bowman described the peculiarities in structure of
this singular parasite. When it has fixed itself upon the flax, the root
and lower part of the stem shrivel up and die away, and a group of
little warts or tubercles is produced from the inner surface of the spire
between each head, which strike into the flax and extract its juices.
This economy places each head nearly in the situation of an independ-
ent plant ; so that, if the stem were separated at intervals, each de-
tached portion would continue to flower and to ripen its seed. This
view occurred to him, on observing that the stem gradually thickened
upwards as it approached each head, and was again reduced to half its
diameter immediately above it ; each head being thus dependent on its
own subordinate system of exhausting suckers. Another beautiful
compensation for the loss of the root, and supporting the view just
advanced, is found in the succulent nature of the flowers, which are as
fleshy as the leaves of the Mesembryanthemum tribe, and contain re-
servoirs of nutriment to insure the ripening of the seed, and supply the
deficiency consequent on the desiccation of the flax.

On the Cultivation of the Cotton of Commerce.
By Major-Gen. Briggs.

The objects proposed in this paper are — First, to excite inquiry on
the various species of cotton plant that produce the cotton of commerce.
Secondly, to ascertain the nature of soils adapted to each. Thirdly, to
prove the practicability of cultivating the plant in India, for the supply
of the British market to any extent. Of the species that produce the
various cottons of commerce, we have at present very little accurate
knowledge, and this has arisen from the alterations undergone by the
plants in the process of cultivation. But there can be no doubt that
the plants which produce cotton in America, Asia, and Africa, are of
decidedly different species. The plant that produces the Brazil cotton,
probably the Gossypium hirsutum, grows to the height of from ten to
twenty feet, is perennial, and produces cotton with a long and strong
staple, and moderately fine and silky. The plant common to the West
Indies, said to have been imported from Guiana, is triennial, bearing
abundantly a fine silky long staple, and is the Gossypium barbadense
of botanists. This also is the plant which produces the Sea-island
cotton. When this plant was carried from the coast into the interior
of Georgia and Carolina, in the United States of America, the seed
changed from a black to a green colour, and the staple became shorter,
coarser, and more woolly. This plant was afterwards introduced into
Egypt, and is the same that produces the Bourbon cotton, cultivated
by the French on that island. Mr. Spalding, in a letter alluded to by
Mr. G. R. Porter, in his work on tropical productions, records several va-
rieties, attention to which is of the greatest importance to the cultiva-
tion, since they vary in the character of their staple, in the shape and

TRANSACTIONS OF THE SECTIONS. 91

size of their pods, in the hue of the cotton, and in the duration of the
plant. The common indigenous plant of India is the Gossypium her-
baceum of botanists, and differs in appearance from the cottons of the
Western world ; besides which, there is the Gossypium religiosum, pro-
ducing the brown cotton, extensively grown in China. The former plant
is usually cultivated as an annual, but has been successfully treated and
grown as a perennial, by the process of pruning down when the cotton
is gathered. The produce of this plant is not inferior in fineness, and
is superior in point of richness of colour, to the best cottons of Ame-
rica. The staple is however short ; and by the great neglect hitherto
evinced in picking the produce at the proper time, and carelessness in
allowing particles of dried leaves, or the calyx of the flower to adhere
to the wool, it fetches a lower price, and is considered an inferior ar-
ticle, in the English market, to the New Orleans and Georgian of
America, though really superior in quality and durability. There is
another kind of cotton produced from a species in Africa, which Dr.
Royle considers allied to the Gossypium herbaceum of India.

Several specimens of American soils on which cotton is grown, have
been analysed by Mr. E. Solly, and he finds them generally to consist
— first, of a preponderating quantity of sand. Secondly, of alumina or
clay. Thirdly, of the oxides of iron and manganese, which give the
varying colours to the soil. Foui'thly, of very small proportions of
carbonate and sulphate of lime. And lastly, of organic matter in two
states; a fibro-vegetable and a soluble matter forming from four to
eight per cent. Soils of this kind, where hardly anything else will grow,
are adapted for the cotton plants of America ; a fact mentioned by Mr.
Porter, and confirmed by Mr. Gray, who was for some years a cultiva-
tor of the plant in America. The land on which the indigenous plant
of India termed Gossypium herbaceum grows, is very different. It is
composed chiefly, not of sand, but of the results of the decomposition
of trap rocks, the debris of the mountains that constitute the extensive
trap formation of central India. This soil lies upon or borders on the
limestone ; it contains a large quantity of vegetable matter, abounds in
oxide of iron, is retentive of moisture, and forms a rich tenacious loam
approaching to clay. Such is the soil of the indigenous cotton plant of
India, and therefore differs from that of America, so that we ought not
to be surprised to learn that all attempts at cultivating the American
plant in this soil have failed. But there are in India abundant other
soils on which the indigenous plant will not thrive. These prevail in
Bengal, on the Coromandel coast, and in fact throughout India. They
consist mainly of the detritus resulting from the disintegration of rocks
of the primary and secondary formations, such as granite, gneiss, sand-
stones, with here and there lime, producing a light soil, fertile or other-
wise according to the quantity of organic matter it may contain. The
indigenous plant will not grow here, but the American plants thrive on
it. This has been proved by experimental farms near Bombay, and
the Western Coast, in Upper Hindustan, on the Malayan Peninsula,
and on the shores of Coromandel, in all of which tracts of Ameri-
can plants are growing at present in much perfection, though not in
quantities sufficient to make any impression on the cotton market of

92 REPORT— 1839.

this country. India could supply all the cotton Great Britain can ever
require, even from her indigenous plants, but for local obstacles. The
soil, favourable to the growth of this article, however, is situated in a
central region removed from the coast, and the trade consequently la-
bours under the difficulty attendant on a lengthened journey by land.
This will not be the case when the cotton is grown on the lighter soils
of the coast. Here every facility exists for its exportation ; for there is
no doubt that an article equally good might be obtained at a much
cheaper rate than that now procured from America.

On the Introduction of a species of Auchenin into Britain, for the
purpose of obtaining Wool. By W. Danson, Esq.

Samples and manufactured specimens of Alpaca wool, in imitation
of silk, and (without die) as black as jet, were exhibited; and Mr.
Danson stated, that the animals producing it ought to be propagated
in England, Ireland, Scotland, and Wales; and to the two latter places
the Alpaca is well suited, being an inhabitant of the Cordilleras, or
mountainous district in Peru. Importations have already taken place
to the extent of one million of pounds, and are likely to increase.
There are five species of Llamas, of which the Alpaca has fine wool,
six to twelve inches long, as shown by the specimens exhibited, the
Llamas, the hair of vvhich is very coarse, and the " Vicuna," which has
a very short fine wool, more of the beaver cast. The Earl of Derby
has propagated the Alpaca in his private menagerie at Knowsley, and
Mr. Danson understood that Mr. Stephenson, at Oban, in Scotland,
has a few of these animals. The wool of these animals would not enter
into competition with the wool of the sheep, but rather with silk. It is
capable of the finest manufacture, and is specially suited to the fine
shawl trade of Paisley, Glasgow, &c. The yarns spun from it are
already sent to France in large quantities, at from Qs. to 12^. 6d. per
pound, the price of the raw Alpaca wool being now 2«. and 2s. 6d. per
pound.

On some recent additions to the English Flora. By Charles
C. Babington, M.A., F.L.S., F.G.S., ^c.

The author stated that the following plants had recently been intro-
duced into the list of natives of England, and made some verbal obser-
vations upon their claim to be considered indigenous, and upon their
specific distinctions : viz.

Nasturtium anceps, Reich.
Cardamine sylvatica, Link.
Sinapis cheiranthus, Koch.
Polygala oxyptera, Reich. ?
Dianthus pluraarius, Linn.
Spergula vulgaris, Boening.
Stellaria umbrosa, Reich.
Hypericum linarifoliura, Vahl.
Oxalis stricta, Linn.
Medicago apiculata, Willd.

Arthrolobium ebracteatum, Desv.
Myriophyllum alterniflorura, DeC.
Callitriche platycarpa, Kutz.
Hypochseris balbisii, Lois.
Hieracium pelliterianum, DeC.
Senecio erraticus, Bert.
Orobanche barbata, Reich.
Scrophvilaria Ehrharti, C A. Stev.
Allium sibericum, Willd.
Iris tuberosa, Linn.

TRANSACTIONS OF THE SECTIONS. 93

Some Observations on an Apparatus for observing Fish (especially of
the family Salmonidoe) in confinement. By Prof. R. Jones.

The points to which attention is required to be directed are the fol-
lowing : — 1st. The salmon, the grilse, and the sea-trout, leaving the
sea in the autumn, for the purpose of depositing their spawn in rivers,
it is desirable to determine whether these are so many distinct varieties,
or the same fish in different stages of its growth. 2nd. With regard to
the whiting (^Scortice, Herling), it is not positively known by fishei-men
whether it spawns at all, or is merely a young fish, which must undergo
a further change before it becomes capable of reproduction. 3rd. The
fry, or young fish, in their first descent from the rivers, exhibit certain
differences of appearance ; but those differences are not such as enable
the fishermen to determine the kind or variety (if any) to which the
young fish respectively belong. 4th. With regard to the par, or brand-
ling, the questions are, whether it is an adult fish sui generis, or the
young of some variety, or the ordinary fry, in an early stage of its de-
velopment. These questions are important, as the decrease of the
British fisheries is very great ; and, by settling them, such provisions
might be made by the legislature as would not only obviate further
diminution, but restore the fisheries to their former abundance. A
model of an apparatus was exhibited, in which it was proposed to con-
fine the fish, in order that obseivations might be made upon them in
their various stages of growth, provision being made for the admission
of sea- and fresh-water, according to the quantity supposed to be re-
quired by the fish in their natural state. Mr. Jones then read a letter
from Mr. Relph, who had been more than fifty years engaged in the
salmon fishery. "In May, 1819," he says, "there were 1700 fry
marked at Kings-gate Fishery, near Carlisle ; and in the July and
August following a quantity of whitings, or herling, were taken, com-
ing from the salt-water, bearing the same marks. These marks were
made by cutting away the fin called the dead fin, just above the tail.
In September, 1821, a grilse was caught bearing the mark, and weigh-
ing 7 pounds, 6 ounces ; so that from the time it was marked its average
growth had been one ounce per week. There were also several salmon
taken bearing the mark, and weighing from 10 to 16 pounds."

Observations on Beroe pileus. By Robert Garner, Esq., F.L.S.

The author has not been able to observe true luminosity in this
animal, even in a perfectly dark room ; but in an obscure room it ex-
hibits peculiar changeable colours.

The vibrations of the external cilia continue after these parts are
separated from the body, with almost undiminished rapidity for several
hours. The circulation of aqueous fluid in the internal canals of the
animal is attributed by the author to the action of minute internal cilia,
situate on the parietes of the cavities. They may also well be seen on
the external sui'face of the stomach Avhere it is washed by the fluid of
the central canal. There is sometimes an appearance of one or more

94 REPORT— 1839.

small bodies varying a little in size and shape attached to the external
parietes of the stomach, not within it, but apparently in the tissue of
the animal.

Mr. Lankester made a communication on some specimens of the
White Bream. Amongst the fish taken at Campsall, is one resembling
the White Bream (^Ahramis hlicca). These fish vary very much, and
do not quite agree with the descriptions given by Mr. Yarrell ; from
which certain distinctions were pointed out by Mr. Lankester.

MEDICAL.

Abstracts of a remarkable case of Rupture of the Duodenum, and of
some other interesting Cases. By Sir David J. H. Dickson, F.R.S.
Ed., F.L.S.

1st. Richard Hawkins, — M. set, 40, was admitted into this hospital
Srd March, 1839, at three o'clock p.m., and died before midnight.
The symptoms were, severe pain in the region of the caecum and as-
cending colon ; quick, restless, impatient manner ; pale, haggard, anx>
ious countenance ; short, hurried respiration, and very weak, quick,
irregular pulse. Depletion and aperients had been resorted to before,
and leeching. Fomentations and purgatives, enemata, &c., after admis-
sion, without affording any relief, and at half-past eleven he expired.
It was ascertained that he had been drinking and wrestling, three days
previously, when he was thrown with violence, backwards, on the breech
of a gun; but he did not suff'er much pain until the morning of admis-
sion, when he felt excruciating pain whilst straining at stool. Dissec-
tion, 40 hours post mortem, discovered the following lesions. The
stomach and bowels were distended with flatus, and there was some
gas in the cavity of the abdomen. The transverse and descending
colon were much contracted ; a quantity of ingesta had escaped from
four perforations near the termination of the duodenum, three of which
were large enough to admit the end of the finger, and from one to two
inches apart. The mucus and muscular coats of this gut were pellucid
and attenuated, as having undergone ramollissement and absorption,
in consequence of which, the peritoneal coat seemed to have given way
from distension or mechanical violence. From its peculiar course, and
the manner in which the duodenum is bound down, Sir David Dickson
deems it fair to infer that this gut may be more liable to injury, from
particular causes, than the more free and floating intestines, — such
as require violent exertions and contortions. It is known that
sudden death frequently follows certain feats of tumbling, horse-
manship, &c., accomplished by retroversion of the body; and, if exami-

TRANSACTIONS OF THE SECTIONS. 95

nation were oftener made, lie think| it probable that similar lesions
would be found, or might exist without being detected, from the exa-
mination not being sufficiently minute ; and hence this cause of death
may more frequently occur than is generally supposed.

The next case detailed was one of Ileus, with enormous distension
of the caecum, which occupied the situation of the transverse colon.
The usual symptoms of Ileus were present — viz. obstinate constipation,
which had lasted for five days, stercoraceous vomiting, and singultus,
&c. The ilio-csecal valve was found to be much thickened and diseased,
and nearly as hard as cartilage ; notwithstanding, a strong membra-
nous band, the product of former inflammation, attached to the lateral
wall and to the mesocolon, extended across the ilium, so as to produce
strangulation ; yet the lower portion of this gut, with the caecum (which
had a black sphacelated appearance, and was much distended,) had
been forced upwards into the above position.

The next, was a case of Intermittent Coma, from diseased brain ; and
remarkable for the alternations of coma, and excitement. The post
mortem examination showed the arachnoid membrane to be opaque, and
raised from the brain by a gelatinous deposit. A considerable effusion
of blood was found at the base of the brain, produced by the rupture
of a true aneurism of the anterior artery of the cerebellum, near its
origin from the basilar artery. The coats of the artery exhibited di-
stinct ossific deposits ; the cerebellum on the left side was wasted, soft
and pulpy, and looked like curdy pus. The aorta was extensively in-
vaded by osseous degeneration ; bony scales as large as sixpences being
separable, and its elasticity was consequently much impaired.

Another case o^ Arachnites, which, besides the usual cerebral appear-
ances, exhibited an extensive deposition of little semicartilaginous
bodies, in the subserous tissue of the abdominal viscera ; — and other in-
stances of Coma were adduced in which depositions of a cartilaginous
or tubercular nature were found in different parts of the brain, abdo-
men, dc.

In a case of Phthisis, the foramen ovale was found open, without
Cyanosis having been produced ; and the patient, a pensioner, had com-
pleted his due period of servitude, and had risen to the rank of sergeant,
without (until latterly) having suffered any particular inconveni-
ence from the communication between the two sides of the heart.

The next case detailed was one of Phlegmonous Erysipelas, occupy-
ing the arm and thoracic muscles of the left side, and remarkable for its
extent and extreme rapidity; — for in three days, besides intense inflam-
mation (followed by effiision) of the pulmonary, costal and diaphrag-
matic pleurae, the vessels, nerves, and muscles of the neck, thorax and
shoulder, down to the elbow joint, were invaded by purulent infil-
tration.

Two cases of severe abdominal disease were also detailed. The one
was a case of constant vomiting from Chronic Pancreatitis, which had
degenerated into scirrhus of that organ, and of the pylorus, together
with deep, and extensive ulceration of the duodenum.

The last case was a most extraordinary instance of Peritonitis, and

96 REPORT— 1839.

Scirrhoma, from the effects of which the patient was reduced to such
extreme emaciation as to resemble, or rather to surpass, that of " L'Ana-
tomie Vivante" Besides effusion in both cavities, and the usual effects of
intense peritoneal inflammation, the stomach, liver, pancreas, colon,
&c., being accreted into one mass of disease, — in the subserous cellular
tissue of the first, and of the large intestines especially, there Avas ex-
tensive ichthyoid deposit of semi-cartilaginous matter, by which the
calibre of the descending colon especially, was so much reduced, that,
when cut across, it appeared as if encircled by a broad ring (in some
places upwards of an inch in thickness), of a dull white, yet glistening,
fish-like substance, but fibriform, and by the interposition of which
the serous was so completely disconnected from the subjacent coats,
that large portions of the latter could be drawn out from the former,
with the utmost facility. Want of space precludes a more copious
detail of the morbid anatomy, or any further observations on the ex-
tent of this heterologous formation, and which was very abundant in
the great end of the stomach, intestines, and other viscera. Taken
altogether, the case is probably unique, and has no prototype on record.

On the Treatment of Capsular Cataract. By R. Middlemore, Esq.

The object of this communication was to introduce to the Section an
instrument to facilitate the operation of extraction, without interfering
with the transparent structures of tlie eye. The instrument consisted
of a needle, accompanied by a small forceps, the former capable of
being withdrawn, leaving the latter to be fixed on the opaque mem-
brane, and then withdrawn through the sclerotic, through which the
needle had been introduced. The author presented some general
views of the disease in question, and compared the methods of opera-
tion commonly used with that to be followed with his own instrument.

On an Operation for Artificial Pupil. By R. Middlemore, Esq.

About three years ago much injury was done to the face of J. S.,
from an explosion of gunpowder. After recovery of the other parts,
the eyes were found to be in the following condition : — the right was
completely collapsed, the left was staphylomatous, the lens adhering to
the staphyloma, but transparent ; the lower half of the cornea was
opaque, the upper half transparent, but vision destroyed, from the closed
iris being opposite to the transparent portion of the cornea. The first
effort was to remove the staphyloma, which was done by repeated
puncturing of it with a fine needle. When the process of removal
was so far completed as to permit the operation for artificial pupil, the
iris was drawn through a small section of the cornea : it bled freely ;
but on the subsidence of the haemorrhage and irritation, a sufficient
and well-defined opening was found in the iris opposite the transparent
portion of the cornea. The external portion of the iris was allowed
to remain strangulated by the incision. The patient has already in a

TRANSACTIONS OF THE SECTIONS. 97

great degree recovered his sight, so as even to distinguish large print.
He is still under treatment.

Results of researches on the Anatomy of the Brain. By Dr. Foville
{of Paris).

He commenced by urging the advantages of examining the struc-
ture of the brain by manual separation rather than by section, and
gave credit to our countryman Willis, as being the first advocate of
this method. He showed that the spinal mariow consists of two lateral
portions, united by two commissures, between which, on the median
line, there exists a double layer of white matter, analogous to the ven-
tricle of the septum lucidum. He pointed out a remarkable difference
of structure in the lateral parts of the spinal marrow, between the
roots of the nerves, which is rendered most evident by maceration in
water, after previous maceration in spirit. He next described the
medulla oblongata. Tracing the crura cerebri to the brain, he showed
them to consist of two parts, — the one going to the thalamus opticus,
the other to the corpus striatum, where they constitute the white
matter ; passing through the middle of those bodies, at the upper and
outer limits of which they divide into three layers, — the superior,
passing upwards and inwards, meets its fellows on the median line,
and forms the corpus callosum ; the second, or middle, is expanded in
the hemispheres, which it constitutes, by lining the cineritious matter
of the convolutions; the third, or inferior, and by far the smallest
layer, passes to the outer side of the thalamus and corpus striatum,
meets its fellow inferiorly, and, ascending with it, forms the septum
lucidum. In addition to these facts, he stated his more recent dis-
covery, of several nearly circular systems of white fibres connecting
the expansions of the superior part of the crus cerebri, which, from
their connexion with the olfactory and optic nerves, and also with the
posterior part of the spinal marrow, appear to be essentially devoted to
sensation. He also stated his fully-confirmed observations, that the
pathological affections of the thalamus influence the movements of the
opposite side of the body, as those of the corpus striatum do those of
the lower extremity. He noticed a similar connexion between the
lesions of the cornu ammonis and the motions of the tongue. He
combated the idea, that the frontal, parietal, and occipital protu-
berances, are dependent on special development of the corresponding
parts of the brain, but are rather to be attributed to the distension of
corresponding parts of the ventricles. After the reading of the paper,
Dr. Foville demonstrated the leading facts alluded to, on the recent
brain.

On the means employed to suppress Hcemorrhage from Arteries.
By Dr. IMacartney.

The progressive improvements made on this subject constitute some
of the most interesting and instructive pages in the history of surgery,
1839. H

98 REPORT— 1839.

inasmuch as they were delayed for ages by the existence of the theory,
which considers inflammation a sanative process, and as their success-
ful applications furnish so many proofs of the falsity of this opinion.

Dr. Macartney, after exposing the errors in practice to which this
error of hypothesis has led, explained some new views on the subject.
In his opinion the common ligature, when it does not succeed, in
almost every instance fails from creating irritation, and consequently a
dilated state of the arteries, or their ulceration ; although much
depends on the plan of after treatment in repelling inflammation, still
the parts feel the presence of the thread, however small, as an extra-
neous body, and therefore do not perfectly return to their natural state
of feeling and action, until the ligature be removed.

" It is well known that metallic substances lie in the living struc-
ture, without exciting in it any irritation, or efibrts to expel them ; I
therefore conceived that a ligature made of leaden wire might be
employed with many advantages. I accordingly made the experiment
of tying both the carotid arteries of a dog with a filament of lead. I
cut off the ends of the leaden wire close to the artery, and healed the
wounds over them. I killed the animal some weeks afterwards, and
found both the vessels obliterated. One of the ligatures remained on
the artery, and the other had been removed by interstitial absorption,
and lay on the side of the vessel. Both were inclosed in a capsule of
transparent cellular membrane ; no lymph had been shed, except what
was sufficient for the consolidation of the divided coats of the arteries.
As the presence of the lead had not created irritation, lymph was not
required to limit or arrest inflammation."

(The appearances were represented in accompanying drawings.)

*' I afterwards tied both the jugular veins of the rabbit in the same
manner. The animal died in two days of apoplexy, as was expected ;
but no appearance of inflammation existed around the veins, and both
ligatures remained on the vessels. These experiments were made
before Dr. Dieffenbach employed the metallic ligature for closing the
fissures of the palate. A considerable improvement has since been
made by Mr. Weiss, by substituting soft metal for the leaden wire.
Weiss's ligature is so flexible, that it admits of being tied in a knot. I
have since had a silver needle, and also a steel one made, for receiving
the end of the metallic ligature, and passing it under an artery."

Several cases are recorded of even large arteries being broken, in
lacerated wounds, without yielding any haemorrhage. In experiments
to discover the reason of this, it was found that, by pulling the artery
slowly until it gave way, it yielded a few drops of blood, after which
no more issued ; and on examining the artery immediately after the
experiment, the matter was fully explained ; it was found that the
middle and internal coats had first been broken. They presented an
inverted edge or burr within the tube ; and the cellular coat, as it
admits of more extension, had been drawn out into the form of an
elongated cone before it gave way ; therefore the hole left at the bottom
of the cone was very minute. There seemed to be no disposition in
the cone of cellular substance to fall back into the cylindric form ; but

TRAXSACTIOXS OP THE SECTIONS. 99

if there had, it would have been resisted by a coagulum of blood filling
it, and which had formed at the instant of the experiment ; and even a
little on the end of the cone for the purpose of soldering up the minute
aperture left by the rupture of the cellular sheath. We perceive,
therefore, that the haemorrhage from even a large artery may be
arrested, by the strength of the cellular tunic, when aided by the dis-
position of the blood to rapidly coagulate. This is soon followed by
the tendency which all arteries possess to contract, when there are no
parts beyond them that require a supply of blood. We thus find the
explanation of the vessels on the face of a stump having a less ten-
dency to bleed, than when the same arteries are tied in aneurism.

Dr. Macartney read a letter from Mr. Darby, of Bray, near Dublin,
describing the entire success which attended the application of a mode
of treatment identical in principle with the views above explained, in
a case of amputation of a child's hand. No ligature or pressure was
used. The stump was covered with a light piece of lint frequently
dipped in cold water, and on the tenth morning the wound was almost
perfectly healed. On these grounds the author expresses hopes that
the day will arrive in which the use of the ligature will become unne-
cessary. He is fully persuaded, that in the operation for aneurism,
(provided the collateral vessels were enlarged,) by making a simple in-
cision and uncovering the artery, and treating it afterwards by cold,
rest, and elevated position, and thus producing union without inflam-
mation, as in other cases where wounds heal by the process of approx-
imation and natural growth, the main artery of the limb would become,
from the sense of exposure, by degrees impervious, which would be
evidently preferable to the sudden interruption of the circulation.

Another case is mentioned by Dr. Macartney, occurring in his own
experience, where the application of ice to a wound of the femoral
artery stopped haemorrhage, when other means had been unsuccess-
fully resorted to.

On the Sounds produced in Respiration, and on the Voice.
By Pe-xton Blakiston, M.D.

Dr. Blakiston commenced by showing that the respiratory sound,
coarse and intense, when heard in the trachea, became gradually
weaker and softer as it approached the periphery of the chest, at
which point the sound, during expiration, had almost totally disap-
peared. The air, in passing along the trachea and bronchial tubes,
would meet with solid obstacles, and therefore be thrown into sonorous
vibration at every alteration of direction. The divergence of sound,
caused by the subdivision of those tubes, and the diminution of their
calibre, would necessarily tend to soften and weaken the respiratory
sounds from the trachea towards the air vesicles ; but the sound pro-
duced by inspiration was carried up to the ear placed on the chest
by the current of air during that act, while that produced by expi-

100 REPORT — 1839.

ration was carried quite in a contrary direction : hence the difference
in intensity. It was next shown that bronchial respiration, occasioned
by solidification of a portion of lung, did not take place in the tubes
leading solely to that portion, as had been supposed by Andral and
Laennec, because no current of air could take place in tubes whose
vesicular extremities had lost their expansibility by which the current
was produced ; but that it took place in tubes leading to healthy ex-
pansible vesicles ; and the ear being brought into contact with the sides
of these tubes, perceived the coarse and comparatively undiverged
sound of the air passing and repassing in them. It was contended that
no sensible part of the sound of vesicular respiration was produced in
or around the vesicles, or by the rubbing of the pleurae, otherwise it
would be clearly heard in expiration ; nor in the mouth or fauces,
otherwise stertorous breathing would increase its intensity ; that conse-
quently it chiefly originated in the bronchial tubes, a supposition ren-
dered very probable by the fact, that it is much affected by sonorous
and sibilous rales.

The voice being an instrument of the membranous reed kind. Dr.
Blakiston then detailed a series of experiments he had made with dif-
ferent kinds of pipes on the wind-chest of an organ, which led him to
conclude that the quality of tone of wind instruments became uniformly
more coarse and buzzing in proportion to the strength of the blast, and
the thinness and elasticity of their sides ; in other words, in proportion
as the instrument itself entered into strong vibration. Some curious
illustrations of the manner in which interference and jarring was pro-
duced between these solid vibrations of the instrument, and those of the
air contained in it, were then given, and it was stated that this law was
applicable to every wind instrument. Among other instances adduced
was that of the flute, in which the upper notes are clear ; and the lower
ones, produced by powerful sonorous waves, affecting the material of the
instrument, are coarse and buzzing. It was shown that both kinds of
vibration were concerned in its formation of the voice, and that hence,
when heard over the larynx, it was perceived to be coarse and intense.
In proportion, however, as these vibrations travelled downwards toward
the air vesicles, they were deadened, the aerial waves by the opposing
current of expiration, and the solid ones by the increasing mass of the
spongy non-homogeneous lung : hence, at the periphery of the lungs,
no resonance of the voice could be detected.

When however a portion of the lung became solidified, the current of
expiration leading from it was stopped, and the spongy lung was trans-
formed into a more homogeneous, and therefore better conducting sub-
stance : hence the voice resounded strongly, and its quality sometimes
became so coarse as to produce a stinging sensation in the ear. Dr.
Blakiston stated that he was now employed in investigating the sub-
ject of the propagation of sound through different media.

TRANSACTIONS OF THE SECTIONS. 101

Notice of an extraordinary case of Spina bifida. By Mr. Evans.

The patient was a boy of twelve years of age, enjoying excellent ge-
neral health in other respects ; he was strong and active, but his head
seemed enlarged from chronic hydrocephalus. The tumour occupied
the lumbar regions, was semi-transparent, and the size of a child's head.

Observations on Poisoning by the Vapours of burning Charcoal.
By GoLDiNG Bird, M.D.

Dr. Bird stated, that he was induced to state the result of some ex-
perimental investigations on this subject, from the discordant opinions
hitherto published on the various questions connected with it in a toxi-
cological point of view. An opinion has been held, that vapours of
carbonic acid were more injurious when produced by the combustion
of coal and charcoal, than from any other source, on account of the ad-
mixture of light carburetted hydrogen gas. This opinion he dissented
from, as it was well known that in coal-mines the fire-damp, as this gas
was called, was inhaled with perfect impunity. To ascertain the modus
agendi of the gas when inhaled, he made numerous experiments, by im-
mersing animals in different mixtures of it and atmospheric air, as well
as in the pure gas. In the latter case, the animals died asphyxiated, as
when immersed in water or mercury, the spasm of the glottis prevent-
ing any portion of it from being inhaled. If not more than twenty-five
per cent, be present, then respiration will go on, and its true poisonous
effects takes place. As to the amount of this gas necessary to produce
fatal effects. Dr. Bird found that, as a general rule, any quantity above
3^ per cent, was capable of producing death. Two opinions prevailed
on the nature of these properties : the first was, that the gas acted ne-
gatively, as pure nitrogen or hydrogen is knoAvn to do, by preventing
the due supply of oxygen. To test this opinion, he formed a mixture
containing twenty-one parts of oxygen, and seventy-nine of carbonic
acid, and death followed instantly from immersion in it ; and the same
result followed when the proportions were reversed, although a taper
burned brilliantly in the latter combination ; showing, that the burning
of a light in any suspected situation is not always a safe test of the ab-
sence of danger. The second opinion is, that this gas, when respired,
exerts a specific poisonous action on the nervous system. This latter,
Dr. Bird adopts, from various considerations drawn from his direct ex-
periments, and from the symptoms observed in numerous cases. These
are principally those denominated cerebral, such as head-ache, vertigo,
suffused eyes, mental horror to an intense degree. Even with these
symptoms, respiration may go on freely. Death is frequently preceded
by vomiting, which is a marked symptom of cerebral disease. In cases
where recovery has taken place, the sequelae are decidedly of nervous
character : they have been, partial paralysis, dumbness, and idiocy ;
and this poisonous effect he thought took place independently of ab-
sorption, from its immediate effects on the nervous system, to which it
was applied. Death has also been induced by its external spplication

102 REPORT— 1839.

to the body, without its being, at the same time, respired. Dr. Bird
related some experiments of Dr. A. T. Thomson, in which the pain of
inflamed surfaces was instantly removed on their being plunged into
carbonic acid. He dwelt on the pathological effects of the gas as ex-
hibited after death, and concluded by pressing the importance of mi-
nute post mortem examinations in every case of death from this cause
coming under the notice of medical men*.

On the Rules for finding with exactness the Position of the Principal
Arteries and Nerves from their Relation to the External Form of the
Body. By Dr. Macartney.

Painters and sculptors have laid down, for the improvement of their
arts, the proportions which belong to the external figure of the human
body, and in doing so have demonstrated a very interesting fact, namely,
that these proportions are in general regulated according to the primary
relations of duplicates or thirds, and the multiples of these. Dr. Mac-
artney has discovered that a similar law of proportion prevails with
respect to the internal parts of the body, more particularly with regard
to the course of the trunks of arteries and nerves in relation to the li-
mits of the external form. Sometimes these parts take a middle line
along the limb for some distance, as may be observed in the trunk of the
sciatic nerve, but more frequently they occupy lines dividing the ex-
ternal form into thirds, or proceed from the median line of one side of
an extremity to the middle of the opposite side, or they may pass from
the middle to the division into thirds, or from a point placed on a line
dividing the external form into three equal parts, and then approaching
the middle so as to form with the fellow two parts of a triangle. Let
us take for instance the course of the arteries in the superior extremity.
The subclavian artery first passes obliquely behind the middle of the
anterior curvature of the clavicle, to the middle of the axilla. The
brachial artery proceeds from the middle of the axilla, to gain a line
dividing the inner third from the two outer thirds of the upper arm,
and ending in the middle position in the bend of the arm. The radial
artery is properly the continuation of the trunk, and passes under a
line drawn from the centre of the fold of the arm to arrive at the place
where we feel the pulse, which is on a division of the external form of
the wrist into fourth parts, or the duplicates of two. The ulnar artery
pursues almost exactly a similar course on the opposite side of the fore
arm, and the inter-osseous takes a middle line. The superficial palmar
arch corresponds in its greatest extent to a line dividing the palm into
two equal parts, and the deep-seated arch exists under a line v/hich
would divide the upper third of the palm from the two lower thirds.

The occipital arteries, after they emerge from the muscles, furnish
us with an example of vessels proceeding from the division of the ex-
ternal form into thirds, towards the median line of the head.

* Dr. Bird's Essay has been published at length in the Guy's Hospital Re-
ports for October 1 839.

TRANSACTIONS OF THE SECTIONS. 103

The course of the trunks of arteries (with two or three exceptions,)
is as much in straight lines from one part to another as that of the nerves,
when the vessels are not displaced by dissection and forcible injection.

The position of the three facial nerves, where they emerge from their
foramina, is almost with perfect exactness upon vertical lines, which
would divide a well-proportioned face into thirds ; but for the purpose
of fixing the points at which these nerves may be divided, the author
has laid down the following rules : a vertical line, drawn so as to pass
midway between the external angle of the orbit and the middle line of
the forehead, will cover the supra-orbital nerve as it escapes from the
notch or foramen, as the case may be, on the superciliary ridge. For the
infra-orbital nerve, the following lines may be drawn : 1st, one perpen-
dicular along the outer side of the second bicuspid tooth ; this will
divide the orbit in the middle. 2nd. A line from the external angular
process of the orbit to between the two middle incisors of the upper
jaw ; this line covers the course of the nerve as it comes out of its
foramen. 3rd. A line may be taken from the lower part of the inter-
nal angular process of the osfrontis to the angle of the lower jaw ; this
line passes across the nerve a few lines beyond its exit from the infra-
orbital hole, and indicates the direction in which the nerve should be
cut. 4;th. If two lines be drawn, one from the internal, the other from
the external angular process, so as to meet and form an equilateral tri-
angle with the horizontal line from the same points, the inferior an-
gle will determine the distance of the foramen from the inferior margin
of the orbit. By the intersection of these lines and their direction, the
most perfect knowledge may be obtained of the position of the infra-
orbital nerve for the purpose of its division.

The mental nerve, immediately on the outer side of its foramen, is
crossed by a line dropped vertically from the superciliary notch. The
height of this nerve on the jaw will vary according as age may have
changed the form of the bone ; but this is of no importance, as the di-
vision of the nerve is best effected on the inside of the mouth, which
produces no deformity.

Dr. Macartney further observes, that the same primary relations re-
gulate all the progressive, and many other movements of all animals
provided with extremities. They also constitute the foundation of the
measure in music, and the rhythm of language. All musical time con-
sists essentially of divisions or bars, containing two or three notes, or
multiples of these numbers, and in no other proportions are we able to
count it. Our powers of perception even are subjected to the same
law of proportion. If we attempt to look at more than two or three
objects at the same moment, and without shifting the attention from
one to the other, we find that it is impossible to distinguish or compare
their differences except by making parcels of them, and then each of
these aggregations represents an unit. The author adds, that the com-
binations of doubles and thirds produce the proportions in all archi-
tectural forms, which yield us the most pleasure to contemplate.

Dr. Macartney began his observations on this subject as early as
the year 1798, and has now had forty-one years' experience of the

104 REPORT— 1839.

advantages to be derived from the possession of positive guides to the
situation of the nerves and arteries which may be concerned in acci-
dents and operations. Mr. Alexander Walker also studied the subject
as early as 1804.

Dr. Macartney then described a remarkable case showing the truth
of his views, and adduced examples from his OAvn experience of the fa-
cility of applying them in practice.

On the Cause of the Increase of Small-Pox, and of the Origin of
Variola- Vaccinia. By Dr. Inglis.

Dr. Inglis stated, that variola was every year upon the increase, the
cause of which was, not that vaccination was inefficient, or that the vi-
rus had degenerated, but that, from a long immunity from small-pox,
the public had ceased to think vaccination necessary. He adduced
proofs from the Cow-pox Institution of Dublin, from foreign reports,
and from the innumerable cases of successful re-vaccination, that the
vaccine virus had not degenerated, but that the human system did un-
dergo a change during some unknown number of years. In Ripon,
during the year 1837, variola prevailed extensively as an epidemic, and
Dr. Inglis observed at that time innumerable eases of varicella; those
affected with chicken-pox were principally children upon whom vacci-
nation had not recently been performed, and those who had chicken-
pox, without vaccination, seldom contracted small-pox. The two dis-
eases appeared to Dr. Inglis to arise from one cause. Many cases, to
prove the convertibility of the one disease into the other, were adduced.
Dr. Inglis, having full faith in the efficacy of vaccination and of re-vac-
cination, after first inserting the vaccine lymph, inserted into his arm
in several places, the virus from variolous patients in different stages of
the disease, and, in one instance, from a patient who was dying from the
disease, but in none of them did he succeed in inducing an eruption ;
the inflammation and pruritus was considerable for a day or two, but
then gradually subsided. That the vaccine virus, therefore, decreases
in its preventive influence, is a supposition at least difficult of proof; for,
from the beginning, this prophylactic pow^er was imperfect in different
degrees, and even an attack of small-pox itself is no certain security
against a second or even a third attack. The next point in the paper
was to show that the two visitations of small-pox and vaccination could
and did go on in the system at one and the same time, distinct cases of
which were brought forward. Now, since two dissimilar contagious ir-
ritations cannot run their course together without the one impeding the
other for a time. Dr. Inglis was led to suppose that variola and variola-
vaccinia had the same common origin, or rather that vaccinia sprung
from variola. The paper concluded by the following brief summary : —
1st. That small-pox is decidedly on the increase, and that during each
successive epidemic there is an increase of variolous patients from
amongst those who were vaccinated in infancy. 2nd. That the vac-
cine virus is as effectual now as ever it was, but that re-vaccination is
necessary after a period of years, as yet unknown. 3rd. That the same

TRANSACTIONS OF THE SECTIONS. 105

cause which produces small-pox during a variolous epidemic in the un-
vaccinated, may and does give rise to chicken-pox in the vaccinated.
And 4th. That there is every reason to believe that cow-pox had its
origin in variola.

On the New Vaccine Virus of 1838. B?/ J. B. Estlin, F.L.S.

The author, in common with many of his professional brethren, hav-
ing long been dissatisfied with the vaccine lymph furnished by the
National Vaccine Establishment, and believing that small-pox after
vaccination had become an event of more frequent occurrence than was
the case formerly, availed himself of an opportunity of procuring some
fresh virus from a dairy farm near Berkeley, in August 1838. Parti-
culars respecting the source of the virus are recorded in the London
Medical Gazette for September 1838. The offer of a supply from this
stock of lymph having been made through the medium of the Medical
Gazette to medical gentlemen connected with public vaccine institu-
tions, numerous applications were made to the author for it, and in the
course of a few months it was in extensive use throughout England ;
its employment at the principal vaccinating establishments in the po-
pulous towns of Birmingham, Bristol, Liverpool, and Manchester, had
it been used nowhere else, would give some importance to the history
of its origin and progress.

The author had carefully preserved this matter distinct from every
other, and had watched its course from the cow for twelve months,
through nearly fifty successive inoculations.

*' During the first three months of the employment of the new lymph,
in a large proportion of cases, a degree of intensity of action was ob-
served quite unusual in the lymph previously used. After the areola
had formed, which seldom commenced before the ninth day, the in-
flammation was considerable ; the constitutional symptoms were often
severe ; and after the subsidence of the areola, in consequence, appa-
rently, of the depth in the cellular membrane to which the vesicle had
extended, the separation of the crust was attended by a secondary in-
flammation very much resembling the process which takes place in the
throwing off of an eschar made by caustic potass. In many examples,
after the coming away of the crusts, deep circular ulcerations remained.
Erythematous attacks affecting the body were not unfrequent, and oc-
casionally erysipelas came on : vesicular eruptions also occurred : many
cases of abscess in the axilla were met with, and sometimes a succession
of boils and small abscesses appeared on the arm and body." Several
medical practitioners, fi'om witnessing the severe effects of the virus,
were induced to discontinue it ; and others who had employed it, had to
endure a portion of obloquy from their less intelligent patients on the
supposition of their having been inoculating with imj^roper virus. The
irritability of the vesicle at this period was so great that children beyond
a few months old usually rubbed and broke it, so that excepting in
young infants, a perfect vesicle was not often met with on the eighth
day, and it was found expedient to inoculate in not more than two
places.

106 REPORT — 1839.

About the month of February in the present year, the vesicle had
acquired a greater degree of firmness, and was seldom found to be
broken during the first week. The author observes, in reference to its
character at the time the paper was read, " at the present time a more
decided change has occurred ; the vesicles usually remain perfect through
their whole progress : erythematous eruptions, as well as abscess in the
axilla, and severe constitutional disturbance, are comparatively rare. I
am then able to state as a decided fact, that the lymph, now forty-eight
removes from the cow, has lost much of the intensity it possessed when
only fifteen degrees from its original source ; while at the same time it
retains all those appearances which Jenner describes as characteristic of
a perfect specimen of the disease."

Full confirmation of the important fact was afforded the author in
the course of his vaccinations, that from some peculiarity of constitu-
tion, lymph taken from a perfect vesicle will produce a pock deficient in
some of the characteristics of the genuine vaccine disease, and that mat-
ter taken from this imperfect vesicle will produce others that are defec-
tive, so that in two or three transmissions the virus may become totally
degenerated. Such a fact being satisfactorily determined, it is idle to
theorize upon the eff'ect which frequent transmissions of virus may have
in ^'^ humanizing" it : the practical point suggested by it is of most con-
sequence — the importance of selecting perfect vesicles only for future
vaccinations.

The paper concluded with a notice of the valuable series of experi-
ments made by Mr. Ceely of Aylesbury, and brought forward in a Re-
port of the Vaccination Section of the Provincial Medical Association
at their late meeting at Liverpool, by which it was proved that small-
pox matter inserted into the cow produced a vesicle in no respect di-
stinguishable from ordinary cox-pox, and yielding lymph, which, when
transferred to the arms of children, had produced the genuine vaccine
vesicle through twenty-four transmissions : thus confirming Jenner's
opinion of the identity of small-pox and cow-pox, and making a most
important contribution to the practice of vaccination by discovering an
easy method of producing the vaccine disease at any time when small-
pox prevailed.

Sir James Murray continued the subject of his paper in the
Seventh Report of the Association, proving, by dissection, that cases
of torturing neuralgia depended in some instances upon the irritation
occasioned by a frost-work of microcosmic crystals deposited in the
nervous membranes ; which crystals, like the crystals of tinea and
lipra, or the discharges from ill-conditioned ulcers, he found to contain
a large proportion of urinary salts. Proofs were adduced that other
complaints and nervous affections originate from acids forming in the
stomach, and impregnating the tissues and circulating fluids with acri-
monious deposits, such as urate of soda: hence he condemned the
internal use of soda in such cases.

It was further shown, that in those gouty and urinary sediments
which prevail after deranged digestion, ^wt^ magnesia was found for

TRANSACTIONS OF THE SECTIONS. 107

thirty years infinitely the most effectual remedy, as also for those acids
which soften the bones and occasion rickets and debility. This fluid
is exempt from the danger of forming concretions in the interior cavi-
ties, as was so often the case when crude magnesia was taken.

The fluid magnesia was then tested, and gave the greatest satisfac-
tion to the Section. Sir James appealed to many members then pre-
sent, from Dublin, Belfast, Edinburgh, and Glasgow, to testify that he
had spent thirty years in bringing this elegant preparation into perfect
condensation, and into a state exempt from all impurities.

On Alkaline Indigestion. By R. D. Thomson, M.D.

The author stated that he had brought this subject before the
British Association at Bristol, but that since that period he had not
only from ample experience confirmed the results of his former in-
quiries, but had elicited several other conclusions of importance. In
the healthy state, there is no doubt that during a portion at least of the
process of digestion, the contents of the stomach are in an acid state.
Whatever this acid may be, there is no doubt that when it accumulates
to a certain extent, the stomach can no longer sustain it, and disease
ensues in the form of heartburn, acid eructations, &c. Where the
contents of the stomach assume any condition offensive to that organ,
either from too much acid or from too small a proportion, the stomach,
in many cases, ejects a clear fluid, which Dr. Thomson has found to
be accompanied by different symptoms, according to the chemical
re-action of the fluid : thus in heartburn an acid fluid is ejected, but
without any cessation of pain in the stomach ; while, on the con-
trary, if a neutral fluid be ejected, according to the experience of the
author, the pain is alleviated on the instant that the fluid is got rid of.
This is a more rare case of indigestion, but the author has met with it
several times. It may be termed Neutral Indigestion. The third form
of indigestion which Dr. Thomson has met with is the alkaline state
of the fluid ejected. He terms it Alkaline Indigestion. The pecu-
liar features of this disease are a violent pain in the region of the
stomach, accompanied sometimes with a feeling of fainting, head-
ache, and more rarely an inclination to vomit. Suddenly a sensation
of spasm comes on, as if some contraction were taking place, and the
patient speedily finds his mouth full of water, which he is obliged to
empty. This operation he has no sooner performed, than he requires
to repeat it, and at last a continuous stream flows from his mouth,
which endures for some time, when it ceases, and along with it the
pain of the stomach. This, together with the chemical re-action of
the fluid ejected, appears to distinguish, in a very complete manner,
alkaline and neutral indigestion from the acid state. The distinction
is the more important, because these diff"erent forms require, in some
measure, opposite modes of treatment. With regard to the cause of
the alkaline re-action, Dr. Thomson stated, that after evaporating the

108 REPORT— 1839.

fluid emitted from the stomach, and igniting the residue, he had
obtained, by crystallization, fine crystals of carbonate of soda. The
presence of these, however, he ascribed either to the decomposition of
common salt by the process, or to the previous existence of lactate of
soda in the fluid. He was more inclined to attribute it to the former
source, because the quantity of crystals was so very considerable.
Dr. Thomson stated that the ejection of these fluids from the stomach
was much more common than was usually imagined, as out of forty or
fifty patients admitted daily at the Blenheim-street Dispensary, in
London, he frequenlty found one or two affected with such symptoms.

On the Red Appearance on the Internal Coat of Arteries.
By Joseph Hodgson, F.R.S,

This appearance, he stated, did not depend on inflammation in every
instance, and should be carefully distinguished from it ; it might occur
extensively, or in small patches, or in different parts of the same sub-
ject, presenting different shades of colour. It was found in subjects
of all ages, in healthy as well as morbid coats, in the lining membrane
of the heart, and of the veins, but less frequently in the latter. It
may be found when blood is present in those cavities after death, or
where they are completely empty. Mr. Hodgson related the experi-
ments of Laennec and Andral, which proved that this red appearance
might be communicated after death by immersing the vessels in blood.
As to the efficient cause, he stated that it might proceed from imbi-
bition, in the same manner as we find the neighbouring membranes
stained with bile from the gall-bladder and its ducts ; the first changes
towards decomposition and putrefaction might allow of it more readily.
Some writers look on it in every instance as the result of inflam-
mation ; slight modifications of vitality may permit its occurrence
during life, as we find it, where chronic inflammation has existed,
giving rise to deposits of an atheromatous matter. When dependent
on inflammation, it will be found affecting the inner coat only ; but
when on other causes, it will often pervade the elastic or middle coat
as well as the serous. Finally, he stated that it might be found de-
pending on the CO- existence of those causes which were capable of
producing it singly.

On the Respiration of Deteriorated Atmospheres.
By C. T. CoATHUPE.

The experiments were instituted to determine whether the injurious
effects which have followed the respiration of charcoal vapours had
depended on carbonic acid, as was generally thought, or on the specific
agency of some other volatile product. The volatile products of the
combination of charcoal he stated to be as follows: — Carbonate of
ammonia, hydrochlorate of ammonia, sulphate of ammonia, volatile

TRANSACTIONS OF THE SECTIONS. 109

empyreumatic oil, carbonic acid gas, carbonic oxide, oxygen, nitrogen,
aqueous vapour.

From a number of experiments on the elimination of carbonic acid
during respiration, he arrived at the following results : — that 266'66
cubic feet of atmospheric air pass through the lungs of an adult in
twenty-four hours, of which 1 0*666 are converted into carbonic acid,
yielding 5*45 ounces of carbon, or 1^4^-628 pounds annually. The
average amount of carbonic acid found in atmospheric air in which
animals had expired was found to be, for warm-blooded animals,
12*75' per cent., for the cold-blooded animals, 13'116 per cent. When
the animals were removed, on becoming comatose, the average amount
of carbonic acid was found to be 10"42 per cent. On confining a
taper until its extinction, the quantity of carbonic acid found was
S'O^e per cent. From hence it would appear, that an atmosphere
which has ceased to support combustion can support animal life for
some time.

Report of Ten Cases of Calculus treated hy Lithotrity.
By Dr. CosTELLo.

The patients were of ages between fifty-three and seventy-six, the
stones varying in size from that of a pigeon's egg to that of a hen's
egg. The lithotrite was successively applied at sittings of from thirty
to fifty seconds. Dr. Costello strongly insisted on the necessity of this
point, especially at the commencement of the treatment, as the consti-
tution is thus saved from the shock and re-action which follow pro-
tracted operation. In one of the cases the collected fragments of the
removed calculus filled a bottle capable of containing at least four
fluid ounces. The patient had suffered upwards of ten years ; during
the treatment he superintended the farming of his estate as usual,
without any inconvenience ; the entire of the ten cases were cured.

On the Cellular Structure of the Ivory , Enamel, and Pulp of the Teeth,
as well as of the Epithelium, and on some other interesting points of
Odontology, By A. Nasmyth, M.R.C.S., F.L.S., F.G.S., Sfc.

On Instruments made from Softened Ivory. By Dr. Ludwig Guter-

BOCK.

Instruments made of softened ivory were presented to the Section,
and described by the author. The ivory, being fashioned to the re-
quired figure, is softened by dilute muriatic acid, which removes the
hardening earth. In a brief memoir. Dr. Giiterbock showed that the
first idea of the preparation was not due either to the German or

110 REPORT— 1839.

Parisian individuals who had claimed the honour, as it was contained
in an English work, published some time ago, under the title of
" Useful Arts and Inventions."

STATISTICS.

Report on the Educational condition of the County of Rutland. By
iHfr. Wm. Langton, on the part of the Manchester Statistical Society.

It was stated that the Society, having previously examined the ma-
nufacturing districts where the population was dense, and the rate of
increase rapid, had resolved to investigate an agricultural district where
the population is scattered and nearly stationary. In comparing the
counties of Rutland and Lancaster, the smallness of the parishes in the
former appears striking, there being a parish church for every 400 in-
habitants ; the Roman catholic population is very small ; there is no
place of worship connected with that sect in the county : 2-7 ths of the
population belong to various sects of Protestant dissenters, the Wesley-
an methodists preponderating, — ^the remaining 5-7th belong to the Es-
tablished Church. The population of Rutlandshire was, in 1811,
16,383 ; in the decennial period between 1811 and 1821, it increased
13 per cent., but in the next decennial period the increase was only
5 per cent. In 1831 the population was —

Males 9,721

Females 9,664

Total 19,385

Taking the scholars of all ages,

1,1 17, or about 5'6 per cent, of the population, attend day and even-
ing schools only.

1,922, or about 9*6 per cent, of the population, attend both day and
Sunday schools.

1,274, or about 6'4 per cent, of the population, attend Sunday
schools only.

4,313

Comparing these numbers with those derived from former investiga-
tions, the following are the results : —

TRANSACTIONS OF THE SECTIONS. Ill

Sunday Schools.

Manchester and Salford 17 per cent, of the population.

Rutlandshire 16

York 12

Liverpool 6

Day and Evening Schools.

York 17 per cent, of the population.

Rutlandshire 15

Liverpool 13

Manchester and Salford 10

There are as many endowed or charity schools in Rutland as there are
parishes, but the majority are not superior to dame and common
schools, and in two thirds of the number no books are provided.
The teachers are generally of irreproachable character ; and the dame-
schools, in quiet, cleanliness, and orderly habits, afforded a very gra-
tifying contrast to the schools of the same class in Manchester and
Liverpool. Industrial education was very limited, but the girls were
generally found sewing or knitting, and in many schools the boys
learned to knit. The attendance of pupils is very irregular, as they
are frequently detained to assist in farm labour at seed time and har-
vest. Out of 53 parishes, 46 have Sunday schools : the teachers are
generally paid, and are most frequently masters and mistresses of day-
schools. There is, however, a great want of systematic visitation.
Good school-books are much wanted ; and though the teachers are
generally moral and respectable, they are not so systematically trained
as to be fit to impart a good education.

Contributions to the Educational Statistics of Birmingham, by a Local
Committee. Read by Francis Clark, Esq.

Mr. Clark stated, that a local committee had been formed to inves-
tigate the statistics of the borough of Birmingham, preparatory to the
meeting of the British Association ; but that in consequence of several
unfortunate circumstances, and particularly the recent riots, which had
engrossed the attention of the more active members, several heads of
inquiry had been abandoned, and the information on others was
meagre and imperfect. A Report on the general state of Education
in Birmingham, prepared by Mr. Wood, agent to the Manchester Sta-
tistical Society, was found to be incomplete, and was, in consequence,
withheld by the committee*. The Educational Returns presented by
Mr. Clark comprised, 1. A return of the numbers, arrangement, and
standing of the boys in the Free Grammar School of Edward VI. ;
2. A return from the Blue Coat School ; 3. A return from the Park-

* This return was prepared for the Birmingham Statistical Society of Edu-
cation. It has been recently published in the London Statistical Journal,
(April, 1840,) with the sanction of a General Meeting of the Society.

112 REPORT — 1839.

street Charity School; 4'. A return from the Deaf and Dumb School. —
1. King Edward's School : The number of boys educated is 44'4.
Branch schools are fast coming into operation in various parts of the
borough, for giving the children in the lower grades of the middle
class a sound English education. The present income is about
4500/., but in three years it will be doubled by the falling in of
leases. — The Blue Coat School, for the education of children belong-
ing to the Established Church. Income, 2715/. annually. Boys edu-
cated, 143 ; girls, 63 ; total, 206. — Protestant Dissenting School, in
Park-street, for girls only. Income, 615/. 6s. 9d. Girls educated, 46.
Products of labour, 7/. 5s. \d. — School for the Deaf and Dumb : The
present numbers are, boys, 22 ; girls, 25 ; total, 47- Of these, 37 were
born deaf and dumb ; 10 became so at a very early age from illness.
In five cases, other members of the same family were similarly
afflicted. To this report were appended some pathological and physio-
logical remarks by M. De Puget, the master of the school, from which
it appeared that the imperfection of the senses most frequently occurs
in the offspring of marriages between first cousins and other near rela-
tions. — Literary and Scientific Institutions : The Philosophical con-
tains about 400, the Mechanics 450, and the Athenaeum 300 members.
To this paper were added, an account of Lench's Trust, a charity for
aged females ; and an account of the number of inquests held during
fourteen years. The average of inquests during the first seven years
is 115, and during the last only 170, though the population has nearly
doubled, and the use of dangerous machinery has increased in a still
greater proportion. The average of accidents from machinery, in the
first period, was 26, and in the second, 37-

A Report on the State of the Working Classes in part of Rutlandshire,
by the Manchester Statistical Society, was read by W. R. Greg, Esq.

The Statistical Society of Manchester having completed and pub-
lished an inquiry into the condition of the working classes in several
large manufacturing towns in the north of England, were desirous of
obtaining similar information with regard to some population differing
in character and circumstances from those which had been previously
examined. For this purpose they selected three parishes in Rutland-
shire, (a purely agricultural county,) which they conceive may be as-
sumed to afford a fair sample of the whole. The information thus
obtained they have arranged in a series of tables, of which we shall
briefly enumerate the most striking results. The parish of Branstown,
which lies on the western side of the county, contiguous to Leicester-
shire, contains about 1400 acres, more than three-fourths of which are
pasture land. It has a population of 1C2 families, comprising 425
individuals ; but there is no resident clergyman, and no resident land-
lord possessing any extensive property. The parishes of Egleton and
Hambleton (^^ hich have been classed together) are situated at a very
short distance from Oakham, the county town, and contain about 2400

TRANSACTIONS OF THE SECTIONS. 113

acres, which are about equally divided between arable and pasture.
The chief part of both these parishes is the property of Mr. Finch, who
resides upon his estates, and has the character of a kind landlord. The
population consists of 100 families, comprising 4-79 individuals. The
first three tables presented to the Section related to the dwellings of
the population ; and the account of them on the whole was satisfactory.
The houses are low, never exceeding two stories ; many of them are
thatched, and nearly all are built of stone. To each a garden is
attached, which is generally of sufficient dimensions to supply the
family with vegetables. Forty per cent, of the dwellings in Branstown,
and 51 per cent, in Egleton and Hambleton, are reported to be well
furnished, which was very nearly the proportion found in Manchester
and Salford. In Dukinfield the proportion well furnished was 61 per
cent. The proportion reported to be comfortable were : — *

In Branstown 50 per cent.

Egleton and Hambleton 65

Manchester 72

Dukinfield 95

The general appearance of the interior of the houses indicated thrifty
poverty, and instances of squalid misery were very rare. Thirty-one
per cent, of the houses in Egleton and Hambleton contained four
rooms, and only 17 per cent, in Branstown. In respect to sleeping
accommodations : —

In Egleton, 14- per cent, of families have more than three

persons in a bed.
Branstown, 19 ditto ditto.

Dukinfield, 33 ditto ditto.

Bury, 35 ditto ditto.

The rent of houses is low : —

In Egleton, the average yearly rent is £2 17 3

Branstown 3

Dukinfield 6 14

Manchester 7 11 8

The proportion of public-houses and beer-shops to the population is —
In Branstown. ... 1 in 85.

Egleton 1 in 240.

The average weekly wages of the heads of families vary from 9^. 7d.
to 10s. 8d., and about one fourth of those under twenty-one are earning
wages. The state of education in these parishes was rather satisfactory.
The tables give the following results : —

Per cent, can read. Per cent, can write.

Branstown 75 44

Egleton, &c 81 50

Manchester 50 Unknown.

Dukinfield 53 28

1839. I

114 REPORT— 1839.

In Egleton, where there is a resident clergyman, the establishment has
82 per cent, of the population ; and in Branstown, which is destitute
of this advantage, only 73 per cent. In conclusion, the Committee
report that their inquiries left a favourable impression as to the moral
condition of these places. Swearing and drunkenness are far from
common ; and the general conduct of the people is marked by sobriety,
frugality, and industry.

Contributions to the Commercial Statistics of Birmingham, prepared
by a Local Committee. Presented by Francis Clark, Esq.

This paper includes returns from the Savings' Bank, the Assay Office,
the Workhouse, and the Assessed Tax office, with a return of the steam
power employed in the borough ; and two others on the occupations
and weekly wages of mechanics. The savings' bank report showed the
satisfactory progress of this institution. It was established in 1827,
and at the close of that year 980 accounts had been opened, and 33
closed, 2,337 deposits were made, to the amount of 10,612/. ; the ave-
rage of each deposit was 4/. lOs. 9c?., and of each account 10/. 16s. 9d.
and the number of depositors 935. At the close of 1838, 1,597 ac-
counts had been opened during that year, and 454 closed; 9,136
deposits entered on the books, amounting to 47,362/. ; the average
of each deposit was 4/. 17^. 4c?., and of each account 17/. lis., and
the total number of depositors, 7,446. The amount of silver marked
at the Assay Office, from its establishment in 1774, has been 4,011,997
ounces; and the weight of gold marked from the year 1825, when
an Act was passed authorizing the assaying of gold manufactures,
has been 27,167 ounces. The total amount of duty received is
105,851/. A curious fact was mentioned in this return ; 25,000
gold wedding rings were assayed and marked at this office in last
year. The workhouse return was complete for 19 years, and ex-
hibited a classified report of the expenditure, with the average number
of paupers, the proceeds of their labour, &c. The return of assessed
taxes showed the amount collected in each year from 1817, and exhi-
bited a very satisfactory improvement in the state of the town. The
total amount of taxes collected in 1816 was about 36,000/., and the
sum paid in 1838, if calculated at the same rate, would have been con-
siderably more than 50,000/. The steam power employed in Birming-
ham is at the present time 3,436 horses power, of which 2,155 horses
power is employed in the metal trades of the town. The number of
steam engines is 240, of which 65 are high pressure, and the remainder
condensing engines. In the first 35 years after the introduction of
steam power, only 42 engines were set to work ; in the next 15 years
78 were erected, and in the last 8 years 120 have been established.
The consumption of coal is estimated at 240 tons per day, and the
number of persons employed at 5,200 males and 1,762 females. The
return of occupations comprised 791 members of a Provident Institu-

TRANSACTIONS OF THK SKCTIOXS. 115

tion, M'ho were divided among no less than 110 different branches of
trade, thus demonstrating the division of labour to an extent far beyond
the calculation of political economists. Of the whole number, 56 per
cent, were workers in the metals. The table of weekly wages showed
the result of an inquiry into 662 cases, of which 479 were taken with-
out choice from the members of the Provident Institution, mentioned
in the last return. The averages were as follows : for boys 7 to 13
years of age 3s. id., and for girls 2s. 4c?. per week ; from 14 to 20 years
5s. 9d. for males, and 5s. 2d. for females ; for men and women 24^. 3d.,
and 8s. per week. Reasons were assigned for the belief that these
averages might be taken as a near approximation to the average wages

Contributions to the Medical Statistics of Birmingham, by a Local
Committee. Presented by Francis Clabk, JEsq.

Elaborate returns were received from the Town Infirmary, the General
Hospital, the General Dispensary, and the Eye Infirmary ; and also a re-
turn from the Superintendent Registrar of the Births, Marriages and
Deaths during the last two years.

The medical institutions are of two different kinds, the first being a
parochial infirmary for the relief of paupers, and the others being sup-
ported by subscriptions. The returns from the Town Infirmary by Mr.
F. Ryland, were confined to the parish of Birmingham, there being
none received from Edgbaston or Aston. They comprised, — 1st, A
return of the number of in-patients for the last seven years ; 2nd, A
return of the number of out-patients relieved in each quarter, for ten
years, with the number who have received pecuniary relief; 3rd, Re-
turns of the occupations and diseases of 9172 males, and 8774 females,
out-patients; and, 4th, A return of the age, sex, and disease of 1518
cases of death among the out-patients. — The returns from the General
Hospital by Mr. S. E. Bindlers, comprised, — 1st, A return of 6133
cases, with the sex, disease and mortality ; 2nd, A return of the num-
ber of in-patients and out-patients, and the amount of subscriptions re-
ceived from the commencement, with the annual expenditure for the
last ten years ; and, 3rd, Four returns, showing the nature of the
fractures in 943 cases occurring in the last two years, and statements
of the results of the cases of paralysis, scirrhous and joint diseases,
which had occurred in the same period. — The returns from the Gene-
ral Dispensary by Mr. F. Ryland, comprised the number of medical
and midwifery cases, and of vaccinations, with the expenditure for the
last ten years. It appeared that, during that period, 29,713 persons
had received medical relief, 7,892 midwifery cases were attended, and
26,089 children vaccinated, at the cost of 13,105/. Is. 3d.\ giving an
average of 45. 9d. as the cost of the sick and midwifery cases. — The
returns from the Eye Infirmary by Mr. Richard Middlemore, gave, —
1st, The number, sex, and cost of the patients, from 1824 to March
i2

116 REPORT— 1839.

1839; 2nd, The number of patients attended, from March 1828 to
March 1835, with the diseases from which they suffered; and, 3rd, A
return of Mr. Middlemore's patients for the year ending March 1839,
giving the disease, sex, age, employment, and colour of the eyes of each
patient, and likewise the result of treatment. The total number of pa-
tients reported is 23,554, and the expenditure 2,161/.; making the ave-
rage cost of each case 1^. 9c?. — With reference to the tables laid before
the Section, the Committee regretted to find that the records of the
various institutions did not afford all the information required to give
value to such documents. In the practice of some of the surgeons
the facts are all recorded, but the house-books do not contain them ;
so that the perfect returns only comprise a small portion of the cases.
The last return produced by the Committee was the Superintendent
Registrar's report, for two years, ending June 30, 1839. The births
reported are 8,218, of which 34-7, or 41 per cent., were born out of wed-
lock. Of the 2,106 marriages, 1,854 were solemnized according to the
rites of the Church of England.

Suggestions in favour of the Systematic Collection of the Statistics of
Agriculture. By G. R. Porter, Esq.

After showing the amount of ignorance on this subject, which is so
great, that to this day the public does not possess any authentic docu-
ment, from which we can learn even the quantity of land under culti-
vation in any county of England, and that the only information available
for further calculation is contained in the estimate of Mr. Couling, who
gave evidence before a Committee of the House of Commons which
was appointed in 1827 to inquire into the subject of emigration, — Mr.
Porter explained the processes by which, in Belgium, Holland and
France, a superior degree of information on agricultural statistics is col-
lected. In a statement published in September, 1838, by the Prefect
of the Department of the Eure, may be found a separate account for
each canton, giving its population and superficial area, the distribution
of the soil, the nature of the crops, the breadth of land appropriated to
each kind, the total produce, the average price of each description of
produce, the quantity used for seed, and the consumption by the native
population. There are also given, the extent of land appropriated to
the growth of wood, and the quantity lying fallow, the number and va-
lue of different kinds of animals reared and kept, the number slaugh-
tered in the year, and the price of each kind of meat. In the course of
a slight examination of this publication, comparing its results with such
facts as we possess concerning the agriculture of our own country, some
very striking differences appear, into the consideration of which it is
not necessary to enter minutely on this occasion. It will, however, be
interesting to state, that the produce of wheat throughout the depart-
ment is not equal, on the average, to quite 18^ bushels to the English
acre, and that the return obtained from the seed sown is not greater

TRANSACTIONS OF THE SECTIONS. 117

than sevenfold, — results