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

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REPORT 



TENTH MEETING 



BRITISH ASSOCIATION 



ADVANCEMENT OF SCIENCE; 



HELD AT GLASGOW IN AUGUST 1840. 



LONDON: 

JOHN MURRAY, ALBEMARLE STREET. 
1841. 



PRJNTED 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 

Recommendations for Additional Reports and Researches in 

Science xxiii 

Synopsis of Money Grants xxxii 

Arrangements of the General Evening Meetings xxxiv 

Address of the General Secretaries xxxv 

REPORTS OF RESEARCHES IN SCIENCE. 

Report on the recent progress of discovery relative to Radiant 
Heat, supplementary to a former Report on the same subject 
inserted in the 1st volume of the Reports of the British Associa- 
tion for the Advancement of Science. By the Rev. Baden 
Powell, M.A., F.R.S., F.R. Ast. S., F.G.S., Savilian Professor 
of Geometry in the University of Oxford 1 

Supplementary Report on Meteorology. By James D. Forbes, 
Esq., F.R.S., Sec. R.S. Ed., Professor of Natural Philosophy in 
the University of Edinburgh 37 

Report, on Professor Whewell's Anemometer, now in Operation at 

Plymouth. By Wm. Snow Harris, F.R.S., &c 157 

a 2 



IV CONTENTS. 

Page 

Report on « The Motions and Sounds of the Heart." By the 
London Committee of the British Association, for 1839-40. . . 163 

An Account of Researches in Electro-Chemistry. By Professor 
ScHONBEiN, of Basle 209 

Second Report upon the Action of Air and Water, whether fresh 
or salt, clear or foul, and at various temperatures, upon Cast 
Iron, Wrought Iron, and Steel. By Robert Mallet, M.R.I.A., 
Ass. Ins. C.E 221 

Report on some Observations on Subterranean Temperature. By 
Robert Were Fox, Esq 309 

Report on the Observations recorded during the years 1837, 1838, 
1839, and 1840, by the Self-registering Anemometer erected at 
the Philosophical Institution, Birmingham. By A. Follett 
Osler, Esq 321 

Report respecting the Two Series of Hourly Meteorological Ob- 
servations kept at Inverness and Kingussie, at the Expense of 
the British Association, from Nov. 1st, 1838, to Nov. 1st, 1839. 
By Sir Davld Brewster, K.H., F.R.S., &c 349 

Report on the Fauna of Ireland : Div. Vertehrata. Drawn up, at 
the request of the British Association, by William Thompson, 
Esq. (Vice-Pres. Nat. Hist. Society of Belfast), one of the Com- 
mittee appointed for that purpose 353 

Report of Experiments on the Physiology of the Lungs and Air- 
tubes. By Charles J. B. Williams, M.D., F.R.S 41 1 

Report of the Committee appointed to try Experiments on the 
Preservation of Animal and Vegetable Substances. Drawn up 
by the Rev. J. S. Henslow, F.L.S., Professor of Botany in the 
University of Cambridge 421 

Provisional Reports, and Notices of Progress in Special Researches 
entrusted to Committees and Individuals 423 



OBJECTS AND RULES 



THE ASSOCIATION. 



OBJECTS. 

The Assoc rATiON 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-beai-ers 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 OP 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 OP 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 the 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 1840. 



OFFICERS AND COUNCIL, 1840-41. 



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

President. — The Most Noble the Marquis of Breadalbane. 

Vice-Presidents. — The Very Reverend Principal Macfarlane. 
Major-Gen. Lord Greenock. Sir David Brewster. Sir Thos. 
Macdougall Brisbane. 

President elect.— Rev. Professor Whewell, F.R.S., V.P.G.S. 

Vice-Presidents elect. — The Earl of Mount Edgcumbe. The 
Earl of Morley. Lord Eliot, M.P. Sir C. Lemon, Bart., 
M.P. Sir T. D. Acland, Bart., M.P. 

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 the Plymouth, Devonport, and Stonehouse 
Meeting in 1841. — Wm. Snow Harris, F.R.S. Col. Hamilton 
Smith, F.L.S. Robert Were Fox, F.R.S. Richard Taylor, 
jun., Esq. 

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

Treasurer to the Meeting in 1841. — Henry Woolcombe, 
Esq. 

Council. — Dr. N. Arnott. R. Brown, Esq. Rev. Dr. Buck- 
land. J. C. Colquhoun, Esq., M.P. Dr. Daubenj-. Sir P. G. 
Egerton, Bart., M.P. Professor T. Graham. J. E. Gray, Esq. 
G. B. Greenough, Esq. W. J. Hamilton, Esq. Dr. Hodgkin. 
R. Hutton,Esq., M.P. H. B. Jerrard, Esq. C. Lyell, Esq. 
Professor Miller. Professor Moseley. The Marquis of North- 
ampton. The Very Rev. Dr. Peacock. E. Pendarves, Esq., 
M.P. Professor Powell. Lord Sandon, M.P. H. E. Strick- 
land, Esq. Lieut.-Col. Sykes. H. Fox Talbot, Esq. N. A. 
Vigors, Esq., M.P. James Walker, Esq. Captain Washing- 
ton. Professor Wheatstone. 

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

Local Treasurers. — Dr. Daiibeny, Oxford. Professor Hens- 
low, Cambridge. Dr. Orpen, Dublin. Charles Forbes, Esq., 
Edinburgh and Glasgow. William Gray, jun., Esq., York. 
William Sanders, Esq., Bristol. Samuel Turner, Esq., Liver- 
pool. Rev. John James Tayler, Manchester. James Russell, 
Esq., Birmingham. William Hutton, Esq., Newcastle- on- 
Tyne. Henry Woolcombe, Esq., Plymouth. 



X REPORT 1840. 

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

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

Francis Baily, V.P. and Treas. R.S 1835. 

General Secretaries. \ R. I. Murchison, F.R.S., F.G.S 1836—1840. 

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

LMajor Sabine, V.P.R.S 1839, 1840. 

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

{Charles Babbage, F.R.SS.L. & E., &c. (Resigned.) 
R. I. Murchison, F.R.S., &c. 
John Taylor, F.R.S., &c. 
Francis Baily, F.R.S. 

Assistant General j Professor Phillips, F.R.S., &c 1832-1839. 

oecretary. J c ' ' 

Members of Council. 

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

Neill Arnott, M.D 1838, 1839, 1840. 

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 .1832,1834,1835,1838-1840. 

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. .1833,1835,1838,1839,1840. 

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. 

J. C. Colquhoun, Esq., M.P 1840. 

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

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

Dr. Daubeny 1838, 1839, 1840. 

J. E. Drinkv?ater 1834, 1835. 

Sir P. G. Egerton, Bart., M.P 1840. 

The Earl Fitzwilliam, D.C.L., F.R.S., &c....l833. 

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, 1840. 

John Edward Gray, F.R.S., F.L.S., &c 1837—1839, 1840. 

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

G. B. Greenough, F.R.S., F.G.S 1832—1839, 1840. 

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

Sir William R. Hamilton, Astron. Royal of 

Ireland 1832, 1833, 1836. 

W. J. Hamilton, Sec. G.S 1840. 

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, 1840. 

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



MEMBERS OF COUNCIL. XI 

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

Robert Hutton, M.P., F.G.S., &c 1836, 1838, 1839, 1840. 

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

Rev. Leonard Jenyns] 1838. 

H. B. Jenard, Esq 1840. 

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. Professor Lloyd, D.D 1832, 1833. 

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

Chancellor of the University of London 1833 — 1836, 1838, 1839. 

Rev. Thomas Luby 1832. 

Charles Lyell, jun., F.R.S 1838, 1839, 1840. 

William Sharp MacLeay, F.L.S 1837. 

Professor Miller, F.G.S 1810. 

Professor Moseley 1839, 1840. 

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

The Marquis of ^lorthampton, P.R.S 1840. 

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

Rev. George Peacock, M.A., F.R.S., &c 1832,1834,1835,1839,1840. 

E. Pendarves, Esq., M.P 1840. 

Rev. Professor Powell, M.A., F.R.S., &c 1836, 1837, 1839, 1840. 

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. 

Lord Sandon,M.P 1840. 

Rev. William Scoresby, B.D., F.R.SS. L. & E.1832. 

H. E. Strickland, Esq., F.G.S 1840. 

Lieut.-Col. W. H. Sykes, F.R.S., F.L.S., &c. 1837—1839, 1840. 

H. Fox Talbot, Esq., F.R.S 1840. 

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, 1836,1840. 

James Walker, Esq., P.S.C.E 1840. 

Captain Washington, R.N 1838, 1839, 1840. 

Professor Wheatstone 1838, 1839, 1840. 

Rev. W. Whewell 1838, 1839. 

William Yarrell, F.L.S 1833—1836. 

Secretaries to the ( Edward Turner, M.D., F.R.SS. L. & E.1832 — 1836. 
Council. (James Yates, F.R.S., F.L.S., F.G.S. 1831—1840. 



xii REPORT — 1840, 

OFFICERS OF SECTIONAL COMMITTEES AT THE 
GLASGOW MEETING. 

SECTION A. MATHEMATICAL AND PHYSICAL SCIENCE. 

President. — Professor Forbes, F.R.S. 

Vice-Presidents. — G. B. Airy, Esq., F.R.S., Astron. Royal. 
Rev. Professor Whewell, F.R.S. Professor James Thomson, 
LL.D. 

Secretaries. — Professor Stevelly. Rev. Dr. Forbes, F.R.S. 
Arch. Smith, Esq. 

SECTION B. CHEMISTRY AND MINERALOGY. 

President. — Dr. Thomas Thomson, F.R.S. 

Vice-Presidents. — Professor Thomas Graham, F.R.S. Pro- 
fessor Johnston, F.R.S. 

Secretaries. — Dr. R. D. Thomson. Dr. Thomas Clark. Dr. 
L. Playfair. 

SECTION C. — GEOLOGY AND PHYSICAL GEOGRAPHY. 

President for Geology. — Charles Lyell, Esq., F.R.S. 

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

Vice-Presidents.— Rev. Professor Buckland, F.R.S. H. T. 
De la Beche, Esq., F.R.S. James Smith, Esq., F.R.S. Capt. 
Washington, R.N. 

Secretaries.— \N. J. Hamilton, Esq., F.R.S. H. E. Strick- 
land, Esq., F.G.S. D. Milne, Esq., F.G.S. John Secular, Esq., 
M.D. Hugh Murray, Esq., F.R.S.E. 

SECTION D. ZOOLOGY AND BOTANY. 

President.— Sir W. J. Hooker, LL.D. 

Vice-Presidents. — The Rev. Professor Fleming, D.D. Sir 
WilUam Jardine, Bart. Professor Graham, F.R.S.E. P. J. 
Selby, Esq., F.L.S. 

Secretaries. — Professor William Couper. Robert Paterson, 
Esq. Edward Forbes, Esq., M.W.S. 

SECTION E. MEDICAL SCIENCE. 

President. — James Watson, Esq., M.D. 

Vice-Presidents. — J. Hodgkin, Esq , M.D. Dr. Andrew 
Buchanan. Dr. John M'Farlane. 

Secretaries. — Professor Couper. Dr. James Brown. Pro- 
fessor Reid. 



OFFICERS OF SECTIONAL COMMITTEES. XIU 

SECTION F. STATISTICS. 

President. — Lord Sandon, F.R.S., M.P. 

Vice-Presidents. — Mr. Sheriff Alison. Rev. Dr. Chalmers. 
Lieutenant- Colonel Sykes, F.R.S. 

Secretaries. — Pi*ofessor Ramsay. R.W. Rawson, Esq. Charles 
R. Baird, Esq. 

SECTION G. — MECHANICAL SCIENCE. 

President. — Sir John Robison, Sec. R.S. Edin. 

Vice-Presidents. — His Grace the Duke of Argyll. The Rev. 
T. R. Robinson, D.D. John Taylor, Esq., Treas. B.A. James 
Walker, Esq., Pres. Inst. Civ. Eng. 

Secretaries. — J. Scott Russell, Esq. Charles Vignoles, Esq., 
C.E. James Thompson, Esq., C.E. James Tod, Esq., Sec. 
Soc. of Arts. 



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. Professor Encke, Berlin. Baron Alexander von Hum- 
boldt, Berlin. M. Jacobi, St. Petersburgh. Professor Liebig, 
Giessen. Professor Link, Berlin. Professor CErsted, Copen- 
hagen. M. Otto, Breslau. 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 460 13 4 

Compositions from Members at the Birmingham Meeting 1 c^o 

and since J 

Subscriptions, 1839 1023 I 

Ditto 1840 2 

Ditto Arrears 1838 18 1 

1555 2 

Dividend on £5500 in 3 per cent, consols, 6 months to\ §2 10 

January 1 840 J 

Ditto £5000 ditto 6 months to Julv last 75 

157 10 

Received on account of Sale of Reports, ^^z. 

1st vol., 2nd Edition 16 14 

2nd vol 12 16 

3rd vol 17 10 

4th vol 26 2 

5th vol 27 4 

6th vol 83 6 

7th vol 160 15 

Lithographs sold 

Dublin Report sold 

Compositions for future publications 

Sale of £500 3 per cent, consols 460 13 6 



344 7 

1 10 

2 3 

75 



£3054 18 1 



W. H. SYKES, "1 

LEONARD HORNER, I. Auditors. 
WILLIAM YARRELL, J 



ADVANCEMENT OF SCIENCE. 



16th August 1839 to the 31st August 1840. 

PAYMENTS. 



£ s. d. 



Expenses of Meeting at Birmingham 

Disbmrsements by General and Local Treasurers 

Salaries to Assistant Secretary, Accountant and Clerk 

Grants to Committees for Scientific purposes, viz. for 

Reduction of Stars in Histoire Celeste 242 10 

Do. do. LacaiUe 4 15 

Catalogue do 264 

Tides' Discussions at Bristol, 1838 100 

Do. do 50 

Subterranean Temperature 13 13 6 

Land and Sea Level 1838 6 11 1 

Atmospheric Air 15 15 

Action of Water on Iron 10 

Do on Organic matter 7 

Foreign Scientific Memoirs, 1838 £100 Ol ,,„ , „ 

Do. do. 1839 12 1 6/ ^ " 

Working Population, 1838 100 

School Statistics, 1838 50 

Forms of Vessels, 1838 184 7 

Meteorological Observations at Plymouth 40 

Mr. Osier's Anemometer do 30 

Professor WheweU's do. do 10 

Meteorological Observations in Scotland (Hourly) 52 17 6 

Magnetical Observations (Instruments) 185 13 9 

Chemical and Electrical Phaenomena 40 

Experiments on the Heart 18 19 

Do. Lungs 8 13 

Reduction of Meteorological Observations 1 8 



£ B. 


d. 


250 





103 11 


1 


247 10 






Paid for Printing Reports, 7th vol 447 15 

Do. Engraving for do 74 4 6 



1548 4 4 



Printing List of Members 

Do. and Advertising, &c 

Sundry Expenses in Publishing Reports 22 12 



i21 


19 


6 


31 





2 


20 


9 


6 



Balance in hands of Bankers 205 17 

Do. Treasurer and Local Treasurers 103 14 6 



309 11 6 



J53054 18 ] 



xvi REPORT 1840. 

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. 

1831-32. 

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 Bi'ewster, 
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, by the Rev. G. Peacock, M.A.,F.R.S.,&c. 

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

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

On the state of our knowledge respecting the Magnetism of 
the Earth, by S. H. Christie, M.A., F.R.S., Professor of Ma- 
thematics, 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 
William Charles Henry, M.D. 



RESEARCHES IN SCIENCE. XVll 

On the recent progressof Physiological Botany, by John Lind- 
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 CoUectorates 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. 
1840. b 



xviii REPORT — 1840. 

1839. 

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

Report on the distribution of Pulraoniferous MoUusca in the 
British Isles, by Edward Forbes, M.W.S., For. Sec. B.S. 

1840. 

Report on the recent progress of discovery relative to Radiant 
Heat, supplementary to a former Report on the same subject 
inserted in the first volume of the Reports of the British Asso- 
ciation for the Advancement of Science, by the Rev. Baden 
Powell, M.A., F.R.S., F.R.Ast.S., F.G.S., Sa\ilian Professor 
of Geometry in the University of Oxford. 

Supplementary Report on Meteorology, by James D. Forbes, 
Esq., F.R.S., Sec. R.S. Ed., Professor of Natural Philosophy in 
the University of Edinburgh. 



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 Pheenomena 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- 



RESEARCHES IN SCIENCE. XIX 

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 Section 
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. 

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. 

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., Savihan Professor of Geo- 
metry 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 diflPerence 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 
b2 



XX REPORT — 1840. 

Greenwich Observations, made as commanded by the British 
Association, by the Rev. T. R. Robinson, D.D. 

On some Experiments on the Electricity of MetalUc 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 pi'oducing 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 
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, 
Esq. 

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

1838. 

Account of a Level Line, measured from the Bristol Channel 
to the English Channel, during the Year 1837-38, 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 Phillips, 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. 



RE SEARCHES IN SCIENCE. XXI 

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 application of the sum assigned forTide Calcula- 
tions to Mr. Whewell, in a Letter from T. G. Bunt, Esq., Bristol. 

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.SS. 
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. 

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

1840. 

Report on Professor Whewell's Anemometer, now in opera- 
tion at Plymouth, by W. Snow Harris, Esq., F.R.S., &c. 

Report on the Motions and Sounds of the Heart, by the 
London Committee of the British Association for 1839-40. 

An Account of Researches in Electro- Chemistry, by Pro- 
fessor Schonbein, of Basle. 

Second Report upon the Action of Air and Water, whether 
fresh or salt, clear or foul, and at various temperatures, upon 
Cast Iron, Wrought Iron, and Steel, by Robert Mallet, 
M.R.I.A., Ass. Ins. C.E. 

Report on the Observations recorded during the Years 1837, 



Xxii REPORT — 1840. 

1838, 1839, and 1840, by the Self-registering Anemometer 
erected at the Philosophical Institution, Birmingham. By 
A. Follett Osier, Esq. 

Report respecting the two series of Hourly Meteorological 
Observations kept at Inverness and Kingussie, at the Expense 
of the British Association, from Nov. 1st, 1838, to Nov. 1st, 

1839. By Sir David Brewster, K.H., F.R.S., &c. 

Report on the Fauna of Ireland : Div. Vertehrata. Drawn 
up, at the request of the British Association, by William Thomp- 
son, Esq. (Vice-Pres. Nat. Hist. Society of Belfast), one of the 
Committee appointed for that purpose. 

Report of Experiments on the Physiology of the Lungs and 
Air-tubes. By Charles J. B. Williams, M.D., F.R.S. 

Report of the Committee appointed to try Experiments on 
the Preservation of Animal and Vegetable Substances. By 
the Rev. J. S. Henslow, F.L.S. 



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

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

On the Dififerential and Integral Calculus, by the Rev. Pro- 
fessor 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 (continuation), by Professor Owen, F.R.S. 

On the Salmonidse of Scotland, by Sir 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- 
fe.ssor Johnston. 

On Molluscous Animals and their Shells, by J. E. Gray, 
F T? 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. 

On the Temperature of the deep Mines of Cornwall, from his 
own observations, by W. J. Henwood, F.G.S. 



RESEARCHES IN SCIENCE. 



On the recent progress and present condition of Electro- 
Chemistiy and Electro-Magnetism, by Professor de la Rive, of 
Geneva. 



Recommendations for Additional Reports and Researches in 
Scieiwe adopted by the General Committee at the Glasgow 
Meeting. 

ADDITIONAL REPORTS ON THE STATE OF SCIENCE REQUESTED. 

Resolved — 
That Professor Airy be requested to furnish a second Report 
on the progress of Astronomy during the present century. 
The date of the former Report, presented by Professor Airy, is 
1831-32. 

That a Committee, consisting of the Astronomer Royal, 
Professor Lloyd, Major Sabine, and Professor Phillips, be 
appointed to report on the publication or other disposal of 
Hourly Meteorological Observations now in possession of the 
Association. 

The Report to be presented at the next meeting of the As- 
sociation. 

That Professor Willis be requested to furnish the Report on 
the state of our knowledge of the Phaenomena of Sound, for- 
merly requested. 

The Report to be presented at the next meeting of the As- 
sociation. 

That Dr. Peacock be requested to furnish the Report on the 
Differential and Integral Calculus, formerly requested. 

The Report to be presented at the next meeting of the As- 
sociation. 

That Professor Wheatstone be requested to furnish the Re- 
port on Vision, formerly requested. 

The Report to be presented at the next meeting of the As- 
sociation. 

That Professor Sir W. Hamilton be requested to furnish the 
Report on the application of a General Principle in Dynamics 
to the Theory of the Moon, formerly requested. 

The Report to be presented at the next Meeting of the As- 
sociation. 

That Professor Kelland be requested to draw up a Report on 



Xxiv REPORT — 1840. 

the History and present state of the Theory of the Undulations 
of Fluid and Elastic Media. 

The Report to be presented at the next meeting of the As- 
sociation. 

That Professor Kelland be requested to furnish a Report on 
the relative state of our experimental and mathematical know- 
ledge on the subject of the Conduction of Heat ; to point out 
the experiments already made which require repetition, and 
those which are necessary to complete the comparison of Theory 
and Experiment. 

The Report to be presented at the next meeting of the As- 
sociation. 

That Professor Bache be requested to furnish his Report on 
the Meteorology of the United States for the next meeting of 
the Association. 

That a Committee, consisting of Mr. Lubbock, Sir J. W. 
Herschel, Dr. Robinson, Professor Forbes, Professor Whewell, 
Professor Miller, Sir David Brewster, and Major Sabine, be 
requested to report to the Association how far the Desiderata 
in our knowledge of the condition of the upper strata of the 
Atmosphere may be supplied by means of ascents in balloons 
or otherwise ; to ascertain the probable expense of such experi- 
ments, and draw up directions for observers in such circum- 
stances. 

The Report to be presented at the next meeting of the As- 
sociation. 

That Professor Johnston be requested to furnish the Report 
on Inorganic Chemistry, formerly requested. 

That Professor de la Rive, of Geneva, be requested to furnish 
the Report on the recent progress and present condition 
of Electro-Chemistry and Electro-Magnetism, formerly re- 
quested. 

The Report to be presented at the next meeting of the As- 
sociation. 

That Professor Johnston be requested to continue his re- 
searches upon Chemical Geology, and to direct his attention 
particularly to the eflfects of igneous rocks. 

That Dr. Daubeny be requested to prepare a Report on the 
connexion of Chemistry and Agriculture, formerly requested. 



RESEARCHES IN SCIENCE. XXV 

That Sir John Graham Dalyell be requested to prepare a 
Report on the habits of the Radiate Animals. 

That the following be a Committee to inquire into and 
report on the experiments made by Mr. C. W. Williams, of 
Liverpool, on the Combustion of Coal and other Fuels, with 
the view of obtaining from them the greatest calorific effect, 
and avoiding the generation of smoke, viz. Mr. Vignoles, Mr. 
Fairbairn, Mr. Grantham, and Mr. Spence. 

That Mr. Hodgkinson be requested to complete his experi- 
ments on the resistance of the Atmosphere to Moving Bodies, 
and to report the result to the next meeting of the British 
Association. 

That the following be a Committee to make experiments 
for ascertaining the comparative eflBciency of the Turbine and 
Common Water Wheels, and to report at the next meeting : — 
Mr. Smith, of Deanston, Professor Gordon, Mr. W. Fairbairn. 



Recommendations of Researches in Science involving Grants 
of Money for Scientijic Purposes, adoj)ted by the General 
Committee at the Glasgoiv Meeting. 

Resolved — 

That Sir D. Brewster and Professor Forbes be requested to 
revise and continue the Hourly Observations at Inverness and 
Kingussie, and that a sum not exceeding 85/. be placed at their 
disposal for the purpose. 

That a Committee, consisting of Professor Whewell, be re- 
quested to superintend calculations on the Tides at Leith by 
Mr. D. Ross, and that the sum of 501. be placed at the dis- 
posal of Professor Whewell for the purpose. 

The Report to be presented at the next meeting of the As- 
sociation. 

That a Committee, consisting of Professor Whewell, be re- 
quested to superintend calculations on Tides at Bristol by Mr. 
Bunt, and that the sum of 50/. be placed at the disposal of 
Professor Whewell for the purpose. 

The Report to be presented at the next meeting of the As- 
sociation. 

That Major Sabine be requested to provide a good mountain 



xxvi UEPORT — 1840. 

barometer and a thermometer for the assistance of Mr. M'Cord 
in his Meteorological Observations, the sum of 20/. to be placed 
at the disposal of Major Sabine for the purpose. 

The Report to be presented at the next meeting of the As- 
sociation. 

That the grant of 100/. for the reduction of Meteorological 
Observations, under the superintendence of Sir J. Herschel, 
be continued. 

The Report to be presented at the next meeting of the As- 
sociation. 

That the Committee already appointed for the revision of the 
Nomenclature of Stars, consisting of Sir John Herschel, Mr. 
Whewell, and Mr. Baily, be re-appointed, and that the sum of 
501. be placed at the disposal of the Committee for the purpose. 

The Report to be presented at the next meeting of the As- 
sociation. 

That the Committee already appointed for the reduction of 
the Stars in the Histoire Celeste, consisting of Mr. Baily, the 
Astronomer Royal, and Dr. Robinson, be re-appointed, and 
that the sum of 150/. be placed at the disposal of the Com- 
mittee for the purpose. 

The Report to be presented at the next meeting of the As- 
sociation. 

That the Committee already appointed to extend the Royal 
Astronomical Society's Catalogue, consisting of Mr. Baily, the 
Astronomer Royal, and Dr. Robinson, be re-appointed on the 
condition originally stipulated, that the Catalogue be called the 
British Association Catalogue, and that 150/. be placed at the 
disposal of the Committee for tliat purpose. 

The Report to be presented at the next meeting of the As- 
sociation. 

That the sum of 40/. be granted to Mr. Osier for the pur- 
pose of completing the Anemometer in the course of erection 
at Edinburgh, and also for Tabulating the Observations from 
the above instruments, in conjunction with those in Birming- 
ham and Plymouth. 

The Report to be presented at the next meeting of the As- 
sociation. 

That a sum of 60/. be placed at the disposal of Sir D. Brew- 
ster, Mr. Osier, and Professor Forbes, for erecting an Ane- 



RESKARCHKS IN SCIENCE. XXVU 

mometer on Mr. Osier's construction at Inverness, to connect 
these Observations witli others already established there. 

The Report to be presented at the next meeting of the As- 
sociation. 

That a Committee, consisting of Major Sabine and Sir J. 
Herschel, be requested to provide two Actinometers, for Ob- 
servations on the intensity of Solar Radiation, to be made by 
Professor Agassiz, at considerable heights in the Alps, and that 
the sum of 10/. be placed at the disposal of the Committee for 
the purpose. 

The Report to be presented at the next meeting of the As- 
sociation. 

That the sum of 75/. be placed at the disposal of Sir D. 
Brewster, for the purpose of an Inquiry into the action of 
Gaseous and other Media upon the Solar Spectrum. 

The Report to be presented at the next meeting of the As- 
sociation. 

That the Committee already appointed to superintend the 
reduction of Lacaille's Stars, consisting of Sir J. Herschel, 
the Astronomer Royal, and Mr. Henderson, be re-appointed; 
and that the sum of 184/. 5s. (the balance of former grant) be 
placed at the disposal of the Committee for the purpose. 

The Report to be presented at the next meeting of the As- 
sociation. 

That a sum not exceeding 20/. be placed at the disposal of 
Mr. Snow Harris, for repairing and observing Whewell's and 
Osier's Anemometers. 

That a sum of 35/. be placed at the disposal of Mr. Snow 
Harris, for defraying the expenses of the Hourly Register of 
the Barometer and Thermometer at Plymouth. 

That the sum of 20/. be placed at the disposal of Professor 
Forbes, for Tabulating Experiments on Subterranean Tem- 
perature. 

That a Committee, consisting of Sir J. Herschel, Professor 
Whewell, Dr. Peacock, Professor Lloyd, and Major Sabine, be 
appointed for conducting the co-operation of this Association 
in the system of simultaneous Magnetical and Meteorological 
Observations, and that a sum of 50/. be placed at their dis- 
posal. 

That a Committee, consisting of Major Sabine, Dr. R. Brown, 



xxviii REPORT — 1840. 

Dr. Robinsoiij Sir J. Herschel, Professor Wheatstone, Sir D. 
Brewster, and Mr. Owen, Professors Thomas Graham and 
Miller, Sir W. Jardine, and Professor Robert Graham, be ap- 
pointed to superintend the Translation and Publication of 
Foreign Scientific Memoirs ; and that the sum of 100^. be 
placed at the disposal of the Committee for the purpose. 

The Report to be presented at the next meeting of the As- 
sociation. 

That Mr. Mallet be requested to continue his experiments on 
the Action of Salt and Fresh Water on Iron, &c., and that 50/. 
be placed at his disposal for that purpose. 

That a Committee, consisting of Dr. Prout, Dr. J. Thomson, 
Professor Owen, Professor Graham, and Dr. R. D. Thomson, 
be requested to undertake a series of Researches on the Che- 
mistry and Physiology of Digestion, and the sum of 200/. to be 
placed at the disposal of the above Committee for the purpose. 

The Report to be presented at the next meeting of the As- 
sociation. 

That a Committee, consisting of Mr. Bryce, Mr. De la 
Beche, and Major Portlock, be requested to continue their Re- 
searches on the Mud of Rivers, and that the sum of 201. be 
placed at the disposal of the Committee for that purpose. 

The Report to be presented at the next meeting of the As- 
sociation. 

That a Committee, consisting of the President of the Royal 
Society, the President of the Geological Society, R. I. Mur- 
chison, Esq., John Taylor, Esq., H. T. De la Beche, Esq., and 
C. Vignoles, Esq. (with power to add to their number), be re- 
quested to take measures for procuring coloured drawings of 
Railway Sections before they are covered up ; 200/. to be 
placed at their disposal for the purpose. 

The Report to be presented at the next meeting of the As- 
sociation. 

That a Committee, consisting of the Marquis of Northamp- 
ton, R. I. Murchison, Esq., and the Rev. W. Buckland, be re- 
quested to enable M. Agassiz to collect materials for a Report 
on the Fossil Fishes of Scotland, and particularly those of the 
Old Red Sandstone ; 100/. to be placed at their disposal for 
that purpose. 

The Report to be presented at the next meeting of the As- 
sociation . 



I 



RESBARCHES IN SCIENCE. XXIX 

That Captain Portloct be requested to institute a set of 
Experiments on the Temperature of Mines in Ireland, and that 
the sum of 10^. be placed at the disposal of Captain Portlock 
for the purpose. 

The Report to be presented at the next meeting of the As- 
sociation. 

That a Committee, consisting of Lord Greenock, Mr. Milne, 
Professor Forbes, Mr. Paterson, Captain Portlock, and Mr. 
Bryce, be requested to Register the shocks of Earthquakes in 
Scotland and Ireland, and that the sum of 20/. be placed at the 
disposal of the Committee for that purpose. 

The Report to be presented at the next meeting of the As- 
sociation. 

That Professor Johnston and Mr. Jeffreys be a Committee 
to repeat Mr. Jeffreys 's experiments on the Solution of Silica in 
water of a high temperature, and that the sum of 25/. be placed 
at the disposal of the Committee for the purpose. 

The Report to be presented at the next meeting of the As- 
sociation. 

That Professor Henslow be requested to continue his Re- 
searches on the Preservation of Animal and Vegetable Sub- 
stances, and that the sum of 6/., being the unexpended portion 
of the former grant, be placed at the disposal of the Committee. 

The Report to be presented at the next meeting of the As- 
sociation. 

That the Committee already appointed for the purpose of 
preparing Maps for the illustration of the Geographical Distri- 
bution of Animals and Plants, have the sum of 251. placed at 
their disposal for the completion of their arrangements. 

That the Committee already appointed for the purpose of in- 
vestigating, by means of the dredge, the Marine Zoology of 
Britain, be requested to continue their researches, and that the 
sum of 50/. be placed at the disposal of the Committee for 
the purpose. 

The Report to be presented at the next meeting of the As- 
sociation. 

That a Committee, consisting of Sir William Jardine, Mr. 
Selby, Mr. Yarrell, and Dr. Lankester, be requested to super- 
intend the application of the sum of 50/. towards the augmenta- 
tion of our knowledge of the Anoplura Britannice. 

That a Committee, consisting of Dr. Lankester, Dr. Arnott, 



XXX REPORT — 1840. 

Dr. Greville, and Dr. Fleming, be requested to draw up a 
Report on the Plants and Animals existing in natural Thermal 
Springs and Mineral Waters, and in solutions artificially pre- 
pared, and that the sum of 61. be placed at the disposal of the 
above-mentioned Committee for the purpose. 

The Report to be presented at the next meeting of the As- 
sociation. 

That a Committee, consisting of Mr. Hugh Strickland, Mr. 
Babington, and Professor Lindley, be requested to institute a 
series of experiments with a view to determine the longest 
period during which the Seeds of Plants can retain their vege- 
tative powers, the species or families of Plants in which these 
powers are of the longest duration, and the circumstances most 
favourable for their preservation, and that the sum of 10/. be 
placed at the disposal of the Committee for the purpose. 

The Report to be presented to the next meeting of the As- 
sociation. 

That the Committee already appointed for preparing a series 
of questions on the Human Race, be requested to complete and 
distribute the questions, and that the sum of 15/. be placed at 
the disposal of the Committee for the purpose of printing and 
distributing the queries. 

The Report of the Committee to be pi'esented at the next 
meeting of the Association. 

That the Committee already appointed for conducting Ex- 
periments on Acrid Poisons be requested to continue their 
labours, and that the sum of 25/. be placed at the disposal of 
Dr. Roupell for the purpose. 

The Report to be presented at the next meeting of the As- 
sociation. 

That the Committee already appointed for Improvements in 
Acoustic Instruments be requested to continue their labours, 
and that the sum of 251. be placed at the disposal of Dr. Yel- 
loly for the purpose. 

The Report to be presented at the next meeting of the As- 
sociation. 

That the Committee already appointed for the investigation 
of the Communication between Veins and Absorbents be re- 
quested to continue their labours, and that the sum of 25/. be 
placed at the disposal of Dr. Roget for the purpose. 

The Report to be presented at the next meeting of the As- 
sociation. 



RESEARCHES IN SCIENCE. XXXI 

That a Committee, consisting of Sir Charles Lemon, Mr. 
Porter, Mr. Hallam, Colonel Sykes, and Mr. Heywood, be re- 
quested to encourage Inquiries into the actual state of Educa- 
tion in Great Britain, considered merely as to numerical ana- 
lysis, and that the sum of lOOZ. be placed at the disposal of the 
above-named Committee for the purpose. 

The Report to be presented at the next meeting of the As- 
sociation. 

That a Committee, consisting of Colonel Sykes, Lord San- 
don, Mr. Porter, Mr. Heywood, Dr. Alison, Dr. Cowan, Mr. 
Chadwick, and Mr. Watt, be requested to inquire into Vital 
Statistics, and that the sum of lOOl. be placed at the disposal 
of the Committee for the purpose. 

The Report to be presented at the next meeting of the As- 
sociation. 

That a Committee, consisting of Professor Johnston, Mr. 
Wharton, Mr. Wilson, Mr. William Murray, Mr. Chas. Baird, 
Mr. Thomas Edington, jun., Mr. De la Beche, and Mr. D. 
Milne, be requested to inquire into the Mining Statistics of the 
British Coal Fields, and that the sum of 25/. be placed at the 
disposal of the Committee for the purpose. 

The Report to be presented at the next meeting of the As- 
sociation. 

That a Committee, consisting of Mr. John Enys, Mr. John 
Taylor, Mr. Fairbairn, Mr. Hodgkinson, Mr. Simpson, and Mr. 
Scott Russell, be requested to obtain a set of Experiments on 
the Temperature of maximum effect in the Condensers of Steam 
Engines, and that the sum of 25/. be placed at their disposal 
for the purpose. 

The Report to be presented at the next meeting of the As- 
sociation. 

That a Committee, consisting of Sir John Robison and Sir 
Thomas Brisbane, be requested to procure, and to hold at the 
disposal of the Association, a set of Roberts's (of Paris) Mea- 
surers of short intervals of Time, to be employ'ed, in the first 
instance, in completing the Experiments on Waves and on the 
Forms of Vessels ; and that the sum of 30/. be placed at their 
disposal for the purpose. 

The instruments to be presented at the next meeting of the 
Association. 

That a Committee, consisting of Professor Moseley, Mr. 
Enys, and Mr. Hodgkinson, be requested to procure the dyna- 



XXxii REPORT — 1840. 

mometric apparatus of Mr. Poncelet, and to obtain a series of 
Experiments on the duty of Steam Engines by means of that 
apparatus ; the sum of 100^. to be placed at their disposal for 
that purpose. 

The apparatus to be presented at the next meeting of the 
Association. 

That the Committee already appointed on the Forms of 
Vessels, be requested to complete their experiments ; the sum 
of 100/. to be placed at their disposal for that purpose. 

The Report to be presented at the next meeting cf the As- 
sociation. 



Synopsis of Sums appropriated to Scientijic Objects hy the 
General Committee at the Glasgow Meeting. 

Section A. 

Hourly Meteorological Observations at Kingussie £ s. d. 

and Inverness 85 

Tide Discussions : Leith 50 

Tide Discussions : Bristol 50 

Mountain Barometer and Thermometer ... 20 

Reduction of Meteorological Observations . . . 100 

Nomenclature of Stars 50 

Stars in Histoire C4leste , 15000 

British Association Catalogue of Stars . . . . 150 

Reduction of Anemometrical Observations . . 40 

Erection of Anemometer at Inverness .... 60 

Two Actinometers 1000 

Action of Gases on Light 75 

Lacaille's Stars 284 5 

Meteorological Observations at Plymouth ... 35 

Anemometer at Plymouth 20 

Tabulation of Experiments on Subterranean Tem- 
perature 20 

Magnetic Co-operation 50 

£1149 5 
Section B. 

Scientific Memoirs 100 

Action of Water on Iron 50 

Chemistry and Physiology of Digestion . . . 200 

£350 



SYNOPSIS. xxxiii 
Section C. 

Mud in Rivers ^ £20 

Railway Sections 200 

Fishes of Old Red Sandstone .' 100 

Subterranean Temperature in Ireland .... 10 

Earthquake Registration 20 

Solution of Silica in Water at High Temperatures 25 

£375 
Section D. 

Preservation of Animal and Vegetable Substances 6 

Skeleton Maps 25 

Marine Zoology 50 

Anoplura Britannias 50 

Plants and Animals in Mineral Waters .... 600 

Vegetative power of Seeds 1000 

Races of Men 15 

£162 
Section E. 

Acrid Poisons 25 

Acoustic Instruments 25 

Veins and Absorbents '. . . . 25 

£75 
Section F. 

Statistics of Education 100 

Vital Statistics lOo o 

Mining Statistics 25 

£225 
Section G. 

Temperature of maximum condensation of Steam 25 

Roberts' Chronometers 30 

Dynamometric Instruments ! ." 100 

Forms of Vessels ! '. 100 



£255 



Total of Money Grants . . . £2591 5 
1840. c 



XXxiv REPORT 1840. 

Extracts from Resolutions of the General Committee. 

Committees and individuals, to whom j^rants of money for 
scientific purposes have been entrusted, are required to present 
to each following meeting of the Association a Report of the 
progress which has been made ; with a statement of the sums 
which have been expended, and the balance which remains dis- 
posable on each grant. 

Grants of pecuniary aid for scientific purposes from the 
funds of the Association expire at the ensuing meeting, unless 
it shall appear by a Report that the Recommendations have 
been acted on, or a continuation of them be ordered by the 
General Committee. 

In each Committee, the Member first named is the person 
entitled to call on the Treasurer, John Taylor, Esq., 2, Duke 
Street, Adelphi, London, for such portion of the sum granted 
as may from time to time be required. 

In grants of money to Committees, the Association does not 
contemplate the payment of personal expenses to the Members. 

In all cases where additional grants of money are made for 
the continuation of Researches at the cost of the Association, 
the sum named shall be deemed to include the specified balance 
which may remain unpaid on the former grant for the same 
object. 



On Thursday evening, September l7th, the President, the 
Most Noble the Marquis of Breadalbane, took the Chair in 
the Theatre. Mr. Murchison read the Address of the General 
Secretaries (see next page). 

On Wednesday, at 3 p.m., the Concluding General 
Meeting of the Association took place in the Theatre, when 
an account of the Proceedings of the General Commit- 
tee was read by Major Sabine. 



ADDRESS 

BY 

RODERICK IMPEY MURCHISON, F.R.S., F.G.S. 

AND 

MAJOR EDWARD SABINE, V.P.R.S. 



IN entering upon the duty assigned to us, we heartily congratulate 
our associates on this our second assembly in Scotland. As on our 
first visit we were sustained by the intellectual force of the metropolis 
of this kingdom, so now, by visiting the chief mart of Scottish com- 
merce, and an ancient seat of learning, we hope to double the numbers 
of our northern auxiliaries. 

Supported by a fresh accession of the property and intelligence of 
this land, we are now led on by a noble Marquis, who, disdaining not 
the fields we try to win, may be cited as the first Highland chieftain 
who, proclaiming that knowledge is power, is proud to place himself 
at the head of the clans of science. 

If such be our chief, what is our chosen ground ?— raised through 
the industry and genius of her sons, to a pinnacle of commercial gran- 
deur, well can this city estimate her obligations to science ! Happily 
as she is placed, and surrounded as she is by earth's fairest gifts, she 
feels how much her progress depends upon an acquaintance with the 
true structure of the rich deposits which form her subsoil; and great 
as they are, she clearly sees that her manufactures may at a moment 
take a new flight by new mechanical discoveries. For she it is, you 
all know, who nurtured the man whose genius has changed the tide of 
human interests, by calling into active energy a power which (as 
wielded by him), in abridging time and space, has doubled the value 
of human life, and has established for his memory a lasting claim on 
the gratitude of the civilized world. The names of Watt and Glasgow 
are united in imperishable records ! 
In such a city, then, surrounded by such recollections, encouraged 
c 2 



by an illustrious and time-honoured university, and fostered by the 
ancient leaders of the people, may we not augur that this Meeting of 
the British Association shall rival the most useful of our previous as- 
semblies, and exhibit undoubted proofs of the increasing prosperity of 
the British Association ? 

Not attempting an analysis of the general advance of science in the 
year that has passed since our meeting at Birmingham, we shall re- 
strict ourselves, on the present occasion, to a brief review of what the 
British Association has directly effected in that interval of time, as re- 
corded in the last published volume of our Transactions. From this 
straight path of our duty we shall only deviate in offering a few gene- 
ral remarks on subjects intimately connected with the well-being and 
dignity of our Institution. 

One of the most important — perhaps the most important service to 
science — which it is the peculiar duty of the Association to confer, is 
that which arises from its relation to the Government, — the right 
which it claims to make known the wants of science, and to demand for 
them that aid which it is beyond the power of any scientific body to 
bestow. In the fulfilment of this important and responsible duty, the 
Association has continued to act upon the principle already laid down 
in the Address of the General Secretaries at the meeting at Newcastle 
in 1838, namely, to seek the aid of Government in no case of doubtful 
or minor importance ; and to seek it only when the resources of indi- 
viduals, or of individual bodies, shall have proved unequal to the de- 
mand. The caution which it has observed in this respect has been 
eminently displayed in the part which it has taken with reference to 
the Antarctic expedition, and to the fixed magnetical observatories. 
It abstained from recommending the former to the Government until 
it had called for, and obtained from Major Sabine, by whom the im- 
portance of such an expedition was first urged, a report in which that 
importance was placed beyond all doubt ; and it withheld from urging 
the latter, although its necessity was fully felt by some of its own 
members, until the letter of Baron Humboldt to the Duke of Sussex 
gave authority and force to its recommendation. 

The delay which has in consequence occurred, has been productive 
of signal benefit to each branch of this great twofold undertaking. 
Since the time alluded to, our views of the objects of investigation in 
terrestrial magnetism have been greatly enlarged, at the same time 
that they have become more distinct. Major Sabine's memoir on the 
Intensity of Terrestrial Magnetism has served to point out the most 
interesting portions of the surface of the globe, as respects the distri- 



bution of the magnetic force, and has indicated, in the clearest manner, 
what still remained for observation to perform ; and the beautiful 
theory of M. Gauss, which has been partly built upon the data af- 
forded by the same memoir, — while it has assigned the most probable 
configuration of the magnetic lines of declination, inclination, and 
intensity, — has done the same service with respect to all the three 
elements. 

In another point of view, also, delay has proved of great value to 
both branches of the undertaking, but more especially to the fixed ob- 
servatories. Our means of instrumental research have, since the time 
of their first projection, received great improvements, as well in their 
adequacy to the objects of inquiry, as in their precision ; and finally, 
the two great lines of inquiry — the research of the distribution of Ter- 
restrial Magnetism on the earth's surface, — and the investigation of 
its variations, secular, periodic, and irregular, — have been permitted 
to proceed pari passu. 

Last of all, the prudent caution, and vigilant care, which the two 
great scientific bodies, the Royal Society and the British Association, 
have exhibited, both in the origin and progress of the undertaking, 
have naturally inspired the Government with confidence ; and while on 
the one hand science has not hesitated to demand of the country all 
that was requisite to give completeness to a great design, so on the 
other, the Government of the country has not hesitated to yield, with 
a liberal and unsparing hand, every request the importance of which 
was so well guaranteed. 

But while we thus enumerate the benefits which have resulted to 
magnetical science from the delay, it must be also acknowledged that 
something has been lost also, not to science, but to British glory. Al- 
though terrestrial magnetism stood forward as the prominent object 
of the Antarctic expedition, yet it was also destined to advance our 
knowledge of the "physique du globe," in all its branches, and especially 
in that of geography. Had the project of an Antarctic expedition 
been acceded to when it was first proposed, viz. at the meeting of the 
British Association, in Dublin, in 1835, there can be no reasonable 
doubt, that a discovery of coast, which by its extent may almost be de- 
signated as that of a Southern Continent, situated in the very region to 
which its eftbru were to have been chiefly directed.must have fallen to 
its lot ; and the flag of England been once more the first to wave over 
an unknown land. But while, as Britons, we mourn over the loss of 
a prize which it well became Britain and British seamen to have made 
their own, it is our part too as Britons, as well as men of science, to 
hail the great discovery— one of the very few great geographical dis- 



coveries which remained unmade ; — and to congratulate those by 
whom it has been achieved, those whom we are proud to acknowledge 
as fellow-labourers, and who have proved themselves in this instance 
our successful rivals in an honourable and generous emulation. 

The caution which has characterized the British Association in the 
origination of this great undertaking, has been followed up by the 
Royal Society in the manner in which it has planned the details, and in 
the vigilant care with which it has watched over the execution. Of 
the success which has attended this portion of the work, the strongest 
proof has been already given in the unhesitating adoption of the same 
scheme of observation by many of the continental observers, and in the 
wide extension which it has already received in other quarters of the 
globe. All that yet remains is to provide for the speedy publication 
of the results. The enormous mass of observations which will be 
gathered in, in the course of three years, by the observatories esta- 
blished under British auspices, and by the Antarctic expedition, will 
render this part of the task one of great expense and labour. To 
meet the former, we must again look to the Government, and to the 
East India Company, who will certainly not fail to present the result 
of their munificence to the world in an accessible form. The latter 
can only be overcome by a well -organized system. The planning of 
this system, will, of course, be one of the first duties of the Royal 
Society ; and it is important that it should be so arranged, that while 
every facility in the way of reduction may be given to those who shall 
hereafter engage in the theoretical discussion of the observations, 
care is taken at the same time that the data are presented entire, with- 
out mutilation or abridgement. The Council of the Royal Society, 
will, doubtless, be greatly assisted in this duty by the eminent indivi- 
dual who has had in every way so large a share in the formation of 
these widely scattered magnetic establishments, and whose own obser- 
vatory, founded by the munificence of the Dublin University, has 
nearly completed a twelve months' magnetic observations on that en- 
larged and complete system of which it set the first example. 

In referring, as we have done, to those most valuable services which 
the Royal Society have rendered, and are continuing to render, in di- 
recting and superintending the details of this great undertaking, in 
both its branches, it is right that, on the part of the British Association, 
we should express the cordial satisfaction and delight with which we 
have witnessed their exertions, united with our own in this common 
cause ; nor should we omit to recognize how much this desirable con- 
currence has been promoted by the influence of the noble President of 
the Royal Society, the Marquis of Northampton, whom, as on so many 



former occasions, we have the pleasure of seeing amongst us, — one 
of our warmest supporters and most active members- 

In the volume of our Transactions now under notice, is contained the 
memorial presented to Lord Melbourne by the Committee of the 
British Association, appointed to represent to Her Majesty's Govern- 
ment the recommendations of the Association on the subject of Ter- 
restrial Magnetism. This memorial is one of many services which 
have been rendered to our cause by Sir John Herschel, whose name, 
whose influence, and whose exertions, since our meeting two years 
since at Newcastle, have largely contributed to place the subject 
where it now stands. The devoted labour of other of our members 
has long been given to an object which they have had deeply at heart, 
viz. the advancement of the science of terrestrial magnetism ; but the 
sacrifice which Sir John Herschel has made of time, diverted from the 
great work, in which his ardent love of astronomy, his own personal 
fame, and his father's memory are all deeply concerned, the more ur- 
gently demands from our justice a grateful mention, because the 
science of magnetism had no claim on him, beyond the interest felt in 
every branch of science, by one to whom no part of its wide field is 
strange, and the regard which a national undertaking such as this de- 
served, from the person who occupies his distinguished station amongst 
the leaders of British science. 

The advancement of human knowledge, which may be reckoned 
upon as the certain consequence of the Antarctic expedition (should 
Providence crown it with success), and of the arrangements connected 
with it, is of so extensive a nature, and of such incalculable importance, 
that no juster title to real and lasting glory than it may be expected 
to confer, has been earned by any country at any period of time; no- 
thing has ever been attempted by England more worthy of the place 
which she occupies in the scale of nations. When much which now 
appears of magnitude in the eyes of politicians has passed into insig- 
nificance, the fruits of this undertaking will distinguish the age which 
gave it birth, and, engraved on the durable records of science, will for 
ever reflect honour on the scientific bodies which planned and promoted 
it, and on the Government which, with so much liberality, has carried 
it into eff^ect. 

Were the value of this Association, Gentlemen, to be measured only 
by the part which it has taken in suggesting and urging this one ob- 
ject, there might here be enough to satisfy the doubts of those who 
question its utility. To overlook such acts as these, and the power of 
public usefulness which they indicate, to scrutinize with microscopic 



xl 

view the minute defects incidental to every numerous assemblage of 
men, to watch with critical fastidiousness the taste of every word 
which might be uttered by individuals amongst us, instead of casting a 
master's eye over the work which has been done, and is doing, at our 
meetings, is no mark of superior discernment and comprehensive wis- 
dom, but is evidence rather of a confinement to narrow views, and an 
indulgence of vain and ignoble passions. 

But to proceed with our useful efforts, — one of the principal ob- 
jects of our Annual Volumes, is the publication in the most authentic 
form of the results of special researches, undertaken by the request, 
and prosecuted in many instances at the cost, of the Association. It 
is a trite remark, that if a man of talent has but fair play, he will soon 
secure to himself his due place in public estimation. We fully admit 
the truth of this in many instances, and above all wliere the points of 
research are connected with commerce and the useful arts ; but many 
also are the subtile threads of knowledge, which, destined at some 
future day to be woven into the great web in which all the sciences are 
knit together, are yet not appreciable to the vulgar eye, and if simply 
submitted to public judgment, would too often meet with silent neglect. 
Numberless, we say, are the subjects (and if your Association exceeds 
a centenary, still more numerous will they be) with which the retired 
and skilful man may wish to grapple, and still be deterred by his want 
of opportunity or of means. Then is it that, adopting the vveil-balanced 
recommendations of the men in whose capacity and rectitude you con- 
fide, you step forward with your aids, and bring about these recondite 
researches, the result of which, in the volume under our notice, we now 
proceed to consider. 

The first of these inquiries to which we advert, you called for at the 
hands of Professor Owen, upon "British Fossil Reptiles," one of the 
branches of Natural History, on a correct knowledge of which the 
development of geology is intimately dependent. 

The merits of the author selected for this inquiry are now widely 
recognized, and he has, with justice, been approved as the worthy suc- 
cessor of John Hunter, that illustrious Scotchman who laid the founda- 
tion of comparative anatomy in the British isles. That this science is 
now taking a fresh spring, would, we are persuaded, be the opinion of 
Cuvier himself, could that eminent man view the progress which our 
young countryman is making towards the completion of the temple of 
which the French naturalist was the great architect. It is therefore a 
pleasing reflection, that when we solicited Professor Owen to work 
out this subject, we did not follow in the wake of Europe's praise, but 



xli 

led the way (as this Association ought always to do), in drawing 
forth the man of genius and of worth ; and the value of our choice has 
been since stamped by the approval of the French Institute. 

If Englishmen* first perceived something of the natural affinities of 
Palaeosaurians, it was reserved for Cuvier to complete all such preli- 
minary labour. The publication of his splendid chapters on the os- 
teology of the crocodile and other reptiles, drew new attention and 
more intelligent scrutiny to these remains ; and it ought to be a sub- 
ject of honest pride to us to reflect, that the most interesting fruits of the 
researches of that great anatomist were early gathered by the English 
palasontologists, Clift and Hume. One of our leadersf, whose report on 
geology ornaments the volumes of this Association, formed the genus 
Plesiosaurus, on an enlarged view of the relation subsisting between 
the ancient and modern forms of reptile life ; while shortly after Buck- 
land established the genus Megalosaurus, and Mantell, Iguanodon and 
Hylceosaurus, worthy rivals of the Geo-Sauri and Moso-Sauri of Cu- 
vier. The other Englishmen who have best toiled in this field, are 
De la Beche, Hawkins, and Sir Philip Egerton. 

Yet although this report is on British reptiles, we are fully alive to 
the great progress which this department has made, and is making, on 
the Continent, through the labours of Count Miinster, Jager, and 
Hermann Von Meyer. The last-mentioned naturalist has been for 
some time preparing a series of exquisite drawings of very many forms 
unknown to us in England, most of which have been detected in the 
" Muschelkalk," a formation not hitherto discovered in the British isles. 
Yet despite of all that had been accomplished in our own country or 
elsewhere. Professor Owen has thrown a new light of classification on 
this subject, founded on many newly discovered peculiarities of osse- 
ous structure, and has vastly augmented our acquaintance with new 
forms, by describing sixteen species o{ Plesiosauri, three of which only 
had been recognisably described by other writers ; and ten species of 
Ichthyosauri, five of which are new to science. Such results were not 
to be obtained without much labour ; and previous to drawing up his 
report, Professor Owen had visited the principal depositories of Ena- 
liosauri described by foreign writers, as well as most of the public and 
private collections of Britain. This, the first part of Mr. Owen's re- 
port, concludes with a general review of the geological relations and 
extent of the strata through which he has traced the remains of British 
Enaliosauri. The materials which he has collected for the second and 
concluding portion of his report on the terrestrial and crocodilean 

* Stukeley. f Conybeare. 



xlii 

Sauria, the Chelonia, Ophidian, and Batrachian reptiles, are equally 
numerous, and the results of these researches will be laid before the 
Association at our next meeting. Deeply impressed as we are with 
the value of this report, we cannot conclude a notice of it, without 
again alluding to its origin, in the words of Professor Owen himself. 
" I could not," says he, " 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 As- 
sociation has liberally granted to me for that purpose." 

Mr. Edward Forbes, whose labours in detecting the difference of 
species and varieties among the existing marine testacea of our shores, 
have been most praiseworthy, has on this occasion given us a valuable 
report on the pulmoniferous moUusca of the British isles. The varia- 
tions in the distribution of the species in this class of animals, are 
shown by him to depend both upon climate and upon soil, the structure 
of the country (or geological conditions) having quite as much share 
in such varied distribution, as the greatest diversity of temperature. 
The Association has also to thank the author for most useful tables, 
which show the distribution of the pulmoniferous mollusca in our is- 
lands, and their relations to those of Europe generally. 

One of the most interesting fruits of modern experimental research is 
the knowledge of the fact, that electrical currents are in continual cir- 
culation below the surface of the earth. Whether these currents, so 
powerful in developing magnetical and chemical phaenomena, are con- 
fined to mineral veins and particular arrangements of metal and rock, 
or generally capable of detection by refined apparatus well applied, ap- 
peared a question of sufficient importance to deserve at least a trial on 
the part of the Association. Our present volume records the result of 
such a trial on the ancient and very regularly stratified rocks of Cum- 
berland, consistincr of limestone, sandstone, shale, and coal, so super- 
imposed in many repetitions as to resemble not a little the common 
arrangement of a voltaic pile. -Varied experiments, with a galvano- 
meter of considerable delicacy, failed, however, to detect, in these 
seemingly favourable circumstances, any electrical current. 

The extensive and rapidly increasing applications of iron to public 
and private structures of all kinds in which durability of material is a 
first requisite, have made it highly desirable topossess accurate informa- 
tion respecting the nature of the chemical forces which eflfect the de- 
struction of this hard and apparently intractable metal. The preser- 
vation of iron from oxidation and corrosion is indeed an object of para- 
mount importance in civil engineering. The Association was, there- 
fore, anxious to direct inquiry to this subject, and gladly availed itself 



xliii 

of the assistance of Mr. Mallet, a gentleman peculiarly qualified for 
such investigations, both from his knowledge as a chemist, and from 
his opportunities of observation as a practical engineer. An extensive 
series of experiments has accordingly been instituted by him, with the 
support of the Association, on the action of sea and river water, in dif- 
ferent circumstances as to purity and temperature, upon a large number 
of specimens of both cast and wrought iron of different kinds. These 
experiments are still in progress, and the effects are observed from 
time to time. They will afford valuable data for the engineer, and form 
the principal object of the inquiry ; but a period of a few years will 
be required for its completion. In the mean time, Mr. Mallet has fur- 
nished a report on the present state of our knowledge of the subject, 
drawn from various published sources, and from his own extensive ob- 
servations. In this report he examines very fully the general condi- 
tions of the oxidation of iron, and how this operation is greatly pro- 
moted, although modified in its results, by sea water ; also in what 
manner the tendency to corrosion is affected by the composition, the 
grain, porosity, and other mechanical properties of the different com- 
mercial varieties of iron. The influence of minute quantities of other 
metals, in imparting durability to iron, is also considered. Mr. Mal- 
let devotes much attention to the consequences of the galvanic asso- 
ciation of different metals with iron, a subject of recent interest from 
the applications of zinc and other metals to protect iron, which are 
at present agitated. He concludes this, his first report, by recommend- 
ing a series of inquiries, ten in number, which will supply the desiderata 
immediately required by the engineer and by the chemist. 

We have next to notice a report by Professor Powell, on the present 
state of our knowledge of refractive indices for the standard rays of the 
solar spectrum in different media. The difficulty which the fact of 
the dispersion of light has offered to the universal application of the 
undulatory theory, has been in a great measure removed by the ana- 
lysis of Cauchy and others, who have considered the distances of the 
undulatory particles as quantities comparable to the length of a wave ; 
velocities of propagation of the different rays of the spectrum are 
made to depend upon the length of wave which constitutes a ray of a 
given colour, and upon certain constants proper to the medium ; these 
constants being obtained from observations on refractive indices for 
certain definite rays (or dark lines) of the spectrum, the refrangibility 
of any other definite ray (whose wave-lengtli has been ascertained by 
examining an interference-spectrum) becomes known, and may be 
compared with observation as a test of theory ; such experiments have 
been made by Frauenhofer, Rudberg, and Professor Powell, who has 



xliv 

given a tabular view of the various results, without, however, insti" 
tuting the comparison between theory and observation, which it would 
be desirable to extend further than has yet been done. It would be 
important also to elucidate the disturbing effect of temperature, which 
prevents even existing observations from being rigorously com- 
parable. 

The calculations respecting the tides, which have been prosecuted 
by the aid of the Association ever since its institution, have been con- 
tinued this year by Mr. Bunt, under the directions of Mr. VVhewell. 
These calculations have now reached such a point, that the mathemati- 
cian, instead of being, as at the beginning of this period, content with 
the first rude approximations, is now struggling to obtain the last de- 
gree of accuracy. 

The country in which we are now assembled, has always been con- 
spicuous for attention to meteorology, a branch of physical science, in 
which the British Association, with its power of combining the efforts 
of many observers in distant quarters of the globe, may hope to be 
especially useful. 

In Scotland, Leslie opened a new train of inquiry, by examining the 
earth's temperature at different depths ; and his successor in the Uni- 
versity of Edinburgh, is now directing, at the request of the Associa- 
tion, a large and complete coui'se of experiments on that interesting 
subject. Framed in conformity with the plans adopted for similar ob- 
jects by Arago and Quetelet, these researches of Professor Forbes 
contain also the means of determining the power of conducting heat, 
which different sorts of rock possess ; and may thus throw light on 
some of those peculiarities in the distribution of temperature at greater 
depths below the surface, which have become known by experience, 
but are not explained by theory. 

In Scotland, Sir David Brewster was the first to obtain an hourly 
meteorological journal for a series of years, and to draw from that fer- 
tile source new and important deductions, which have had a powerful 
influence on the progress of scientific meteorology. How gratifying 
to receive, through the same hands, after the lapse of nearly 15 years 
anadditional contribution of the same kind, and from the same country ; 
but embracing new conditions, on a new line of operations, in order to 
obtain new results ! By the observations now in progress at Inverness 
and at Kingussie, the influence of elevation in modifying the laws, 
which have been found to govern the hourly distribution of heat near 
the level of the sea, may be discovered, and thus a great addition be 
made to the experimental results, for which science has long been 
grateful to the distinguished philosopher we have named, and which 



have been described as " the highest value to meteorology, and as the 
only channel through which any specific practical information can be 
obtained in this most interesting department of physics." 

This is no ordinary praise. It is the just tribute of one who is 
worthy to offer it ; one, who at the call of the British Association, has 
conducted at Plymouth a still more extensive series of similar obser- 
vations, and has added to them hourly comparisons of the temperature 
and moisture of the air, and an hourly record of barometric oscillations. 
Mr. Snow Harris has presented in a few pages of our last report, the 
precious results of (70,000) observations, and thus rendered them 
immediately available in the foundations of accurate meteorology. 
The documents thus patiently collected, are, however, not yet ex- 
hausted in value ; they may be again and again called into the court of 
science, and made to yield testimony to other, and as yet, unsuspected 
truths. They must not be lost. Shall we lay them by in manuscript 
among other unconsulted records of the past labours of men, or by un- 
dertaking their publication, do justice to our workmen, and establish a 
new claim on the imitation of the present, and the gratitude of future 
days ? This question is of serious import. Already, stimulated by 
success in thermometric registration, we have set to work on a more 
perplexing problem ; we have resolved to bind even the wandering 
winds in the magic of numbers. While we speak, the beautiful engines 
of our Whewells and Osiers are tracing at every instant of time, the 
displacements of the atmosphere at Cambridge, at Plymouth, at Bir- 
mingham, in Edinburgh, in Canada, in St. Helena, and at the Cape of 
Good Hope ; and ere long we may hope to view associated in one dia- 
gram, the simultaneous movements of the air over Europe, America, 
Africa, India, and Australia, recorded with instruments which we have 
chosen, by men whom we have set to work. 

Amongst the causes which tend to retard the progress of science, 
few, perhaps, operate more widely than the impediment to a free and 
rapid communication of thought and of experiments, occasioned by 
difference of language. It appeared to the British Association, that 
this impediment might in some degree be removed, as far as regards 
our own country, by procuring, and causing to be published, transla- 
tions of foreign scientific memoirs judiciously selected. Accordingly 
at eacli of the meetings at Newcastle and Birmingham a grant was 
placed at the disposal of a committee appointed to carry this purpose 
into effect. Aided by several contributions which have been gratui- 
tously presented to them, the committee have been enabled in the two 
last years, to publish translations of fourteen memoirs on subjects of 



xlvi 

prominent interest and importance in the mathematical and physical 
sciences, bearing the names of some of the most eminent of the con- 
tinental philosophers. 

In concluding this imperfect review of our recent proceedings, we 
are led to observe, that in two essential respects the British Association 
differs from all the annual scientific meetings of the Continent; no one 
of which has printed Transactions or employed money in aiding special 
researches. We also differ from them in the communications which, 
in the name of the representatives of science assembled from all parts 
of the United Kingdom, we feel ourselves authorized to make to our 
Government, on subjects connected with the scientific character of 
the nation. On our first visit to Scotland, for example, we felt it to 
be an opprobrium, that this enlightened kingdom should, in one essen- 
tial feature of civilization, be still behind many of the continental states; 
and we prepared an address to his late Majesty's Government, urging 
the necessity for the construction, without delay, of a map of Scotland, 
founded on the trigonometrical survey. Representations to the same 
effect have since been made by the Royal Society of Scotland, and 
by the Highland Society, and the subject has now engaged that atten- 
tion, which will, we trust, soon procure for this country the first sheets 
of a large and complete map. 

Should it then be asked, why are the men of highest station happy to 
associate and mingle with us in official duties ? — why have the heads 
of the noble houses of Fitzwilliam, Lansdowne*, Northampton, Bur- 
lington, Northumberland, and Breadalbane, alternated in presiding over 
us, with our Bucklands, our Sedgwicks, our Brisbanes, our Lloyds, and 
our Harcourts? — why indeed, on this very occasion, has Argyll himself, 
overlooking the claims due to his high position, and his ancient lineage, 
come forward to act with us, and even to serve in a subordinate office ? 
may we not reply, that it is, we believe, a .consequence of the just ajj- 
preciation on the part of these patriotic and enlightened noblemen, of 
the beneficial influences which this Association exercises in so many 
ways on the sources of the nation's power and honour ? 

If we have hitherto dwelt almost exclusively on the value of our 
transactions, researches, recommendations, and the good application 
of our finances, let it not, however, be supposed, that we are not also 



*The Marquis of Lansdowne, who had accepted the office (1836), was prevented 
from attending by deep domestic affliction, and the Marquis of Northampton cheer- 
fully supplied his place. 



xlvii 

alive to the advantages which flow from the social intercourse of these 
meetings, by bringing together, into friendly communion, from distant 
parts, those who are struggling on in advancing experimental science. 
This principle of union (which we are proud to have borrowed from 
our German brethren) has indeed been hitherto found to work so well 
amongst our own countrymen, that we cannot but doubly recognize its 
value when we see assembled so many distinguished persons from 
foreign countries. In the presence of these eminent men*, we forbear 
to allude to individual distinctions, conscious that any brief attempt of 
our own would fall far short of a true estimate of merits, the high 
order of which is known to every cultivator of science. Well, how- 
ever, may we rejoice in having drawn such spirits to our Isle ; valuable, 
we trust, may be the comparisons we shall make between the steps 
which the sciences are making in their countries and in our own. 

That advantages, indeed, of no mean order arise from such social 
intercourse, is a feeling now so prevalent, that foreign national associa- 
tions for the promotion of natural knowledge, have rapidly increased. 
Germany, France, and Italy have their annual Assemblies, and our 
allies of the Northern States hold their sittings beyond the Baltic. 
In all this there is doubtless much good, but an occasional more exten- 
sive intercoui'se of a similar nature, to be repeated at certain intervals, 
is greatly to be desired. 

It has therefore appeared to us (and we say it after consultation with 
many of our continental friends, who equally feel the disadvantage), 
that the formation of a general congress of science might be promoted 
at this meeting, which, not interfering with any assemblies yet fixed 
upon, or even contemplated, may be so arranged as to permit the at- 
tendance of the officers and active members of each national scientific 
institution. 

Should the British Association take the first step in proposing a 
measure of this kind by soliciting the illustrious Humboldt to act 
as President, we are sure that scientific men of all nations would 
gladly unite in offering this homage to a man whose life and fortune 
have been spent in their cause, whose voice has been so instrumental 
in awakening Europe to the inquiry into the laws of terrestrial mag- 
netism, and whose ardent search after nature's truths has triumphed 
over the Andes and the Altai. 

If such be your suggestion, then will a fresh laurel be added to the 
wreath to this city. She who, through the power bequeathed to her by 

* Encke, Link, Jacobi, &c. 



xlviii 

her illustrious offspring, conveys with rapid transit her inventions and 
her produce to the remotest lands, well can she estimate the value of 
an union of men whose lahours can but tend to cement the bonds of 
general peace. In such a body the British representatives would, we 
trust, form no inconspicuous band ; and with minds strengthened by 
the infusion of fresh knowledge, they would, on re-assembling for our 
own national ends, the better sustain the permanent and successful 
career of the British Association, 



REPORTS 



THE STATE OF SCIENCE. 



Report on the recent progress of discovery relative to Radiant 
Heaty supplementary to a former Report on the same sub- 
ject inserted in the \st volume of the Reports of the British 
Association for the Advancement of Science. By the Rev. 
Baden Powkll, M.A., F.R.S., F.R.Ast.S., F.G.S., Savilian 
Professor of Geometry in the University of Oxford. 

JjLAVING been one of those whoat the first institution of the 
British Association were applied to, to prepare reports on the 
state and progress of the different branches of science, and ha- 
ving in consequence laid before the Association at the Oxford 
meeting in 1832 such a review of the subject of Radiant Heat, 
I have felt peculiar satisfaction in being again honoured by a 
request from the Council to furnish a second report supplement- 
ary to the former, embracing the progress of knowledge in that 
department from the period to which the first report extends, 
up to the present time. 

Such a supplementary account has been rendered peculiarly 
necessary, from the great number and high importance of the 
results which have been arrived at by several eminent experi- 
menters in the interval which has elapsed : and though much 
is still required to be done before we attain complete and satis- 
factory grounds for an unexceptionable theory of radiant heat, 
yet the discoveries recently made have at least tended greatly 
to modify all our previous conceptions, and to enable us to refer 
large classes of the phsenomena to something like a simple and 
common principle. 

In my former Report I divided the subject under various heads, 
derived from what appeared, in the existing state of our know- 

VOL. IX. 1840. B 



2 REPORT — 1840. 

ledge, well-marked distinctions between several kinds of effects 
ascribed to radiant heat. The more recent discoA^eries have in 
a great degree so changed our views of the subject, that these 
divisions cannot with any advantage or convenience be adhered 
to. One grand principle of arrangement, however, has been 
newly supplied in the capital discovery of the polarization of 
heat ; so that all the researches we have to describe will be conve- 
niently classed under two heads, as they relate — first, to radiant 
heat in its ordinary or unpolarized state ; and secondly, to its 
polarized condition. 

Division I. — Unpolarized Heat. 

Transmission and Refraction of Heat : Melloni. 

Since the period to which my former report extends, various 
notices have from time to time been given to the British Associa- 
tion relative to the more important discoveries connected with 
radiant heat. My former report includes a statement of some 
of the first researches of M. Melloni. At the Cambidge meet- 
ing, in 1833, Prof. Forbes gave some account of the further 
investigations in which M. Melloni was then engaged, including 
a brief abstract by M. Melloni himself of the chief results he 
had then obtained*. The full details were subsequently embo- 
died in his several memoirs. 

In the earlier part of these researches, M. Melloni had found 
that the quantity of calorific rays which traverses a screen, is 
proportional to the temperature of the source : but the difference 
constantly diminishes as the thickness of the screen is less, until 
with very thin laminae it is insensible. 

This proves that the resistance to the passage of heat is not 
exerted at the surface, but in the interior of the mass. 

Witli the solar raj^s, he observed that with various thicknesses 
of sulphate of lime, water and acids, the increase of interception, 
owing to increased thickness, is greater for the less refrangible 
rays of the spectrum. 

With terrestrial sources he found that a plate of glass, 2 mm. 
in thickness, stops, out of 100 rays, from flame 45, from copper 
at 950° cent, (incandescent) 70} from boiling mercury 92, from 
boiling water 100. 

Comparing the transmissive powers of a great number of 
substances in a crystallized state, he concluded that the diather- 
maneity for the rays of a lamp was proportional to their refrac- 
tive powers ; but in uncrystallized bodies no such law could be 
traced. 

* See Tliird Report, p. 381-2. 



REPORT ON RADI.^NT HEAT. 3 

It was in the course of these researches that the author made 
the important discovery of the singular property possessed by 
Rock Salt, viz. that it is ahnost entirely permeable to heat even 
from non-luminous sources. He found its transmissive power six 
or eight times greater than that of an equal thickness of alum, 
which had nearly the same transparency and refractive power. 
He also discovered that (unlike other diathermanous media) it 
is equally diathermanous to all species of heat, i. e. to heat from 
sources of all degrees of luminosity or obscurity; or that it 
transmits in every case an equal proportion of the heat incident. 

Thus he found a plate of 7 mm. ('28 inch) in thickness trans- 
mits about 92 out of 100 rays, whether from flame, red-hot iron, 
water at 212°, or at 120° Fahrenheit. A plate 1 inch thick gave 
a similar constant ratio. 

M. Melloni's " Memoir on the Free Transmission of Radiant 
Heat through Solid and Liquid Bodies," was presented to the 
Academy of Sciences at Paris, Feb. 4, 1833, and published in 
the Ann. de Chimie, No. liii. p. 1 ; a translation of it is given in 
Taylor's Scientific Memoirs, Part I. 

The author commences with a slight sketch of the researches 
of previous experimenters, but omits to notice any distinctions 
between the characters of the heat from different sources, or the 
different kinds of heat from one and the same source, when lu- 
minous, especially as indicated by my experiments published in 
the Phil. Trans, for 1825. 

He then proceeds to some " general considerations on free 
transmission of caloric through bodies, and the manner of mea- 
suring it by means of the thermo-multiplier." This, in fact, con- 
stitutes a supplementary and more enlarged portion of his for- 
mer researches. He goes into extensive details on the precau- 
tions necessary to be used in such investigations ; especially for 
guarding against the interference of secondary radiation : as 
this changes with the change of place of the screen, he thus al- 
lows for its effects. He also gives some general observations 
on the use of the galvanometer, and the correct estimation of the 
forces acting upon it. 

The next subject of inquiry is the effect due to " the polish, 
thickness, and nature of the screens." The source of heat being 
a lamp, screens were employed of glass rendered of different de- 
grees of opacity by grinding, &c. ; and the effects by transmis- 
sion through them were found to be in proportion to the trans- 
parency, or that the heat follows the same proportion as the 
light. 

The effect of liquids between glass plates was then tried ; and 
more rays were found to be absorbed in proportion to the increase 

B 2 



4 ' REPORT — 1840. 

of thickness. Different numbers of glass screens were also em- 
ployed in combination ; the same conclusion also held good. 

The results with a numerous series of screens of various me- 
dia, solid and liquid, were then tried, and are stated in a series 
of tables : — 

Table I. Various kinds of uncoloured glass. 
Table II. Liquids : to give a general sketch, the order of 
transmission was as follows, beginning with the greatest : — 
Carburet of silver. 
Chlorides. 
Oils. 
Acids. 
Water. 
Table III. Crystallized bodies, transparent and opake ; the 
results follow no relation to transparency: the following is the 
general order: — 

Rock salt. 
Various crystals. 
Alum. 

Sulphate of copper — no effect. 
Table IV. Coloured glasses. Red and violet transmitted 
most — yellow, green and blue, least— heat. 

The author concludes, in general (the source being a lamp), 
that the diathermancy is not proportional to the transparency ; 
and makes some general remarks on these results as related to 
those of Seebeck on prismatic dispersion. 

A supplement to the last paper was presented by the same 
author to the Academy, April 21, 1834, entitled "New Re- 
searches on the immediate Transmission of Radiant Heat 
through different Solid and Liquid Bodies." It is published hi 
the Ann. de Chimie, Iv. 337, and translated in Taylor's Scien- 
tific Memoirs, Part I., p. 39. 

The author first investigates "the modifications which calo- 
rific transmission undergoes in consequence of the radiating 
source being changed." 

He employs four sources of heat. 1. A Locatelli lamp. 2. 
Incandescent platina. 3. Copper heated by flame to about 7-^0° 
Fahrenheit. 4. Hot water in a blackened copper vessel. The 
heat from each of these sources was first compared as transmit- 
ted through plates of glass of different thicknesses, from '07 
millims. to 8 millims. The results are given in a table, from 
which it appears that with copper and hot water the diminution 
of effect is rapid, with an increase of thickness in the screen; with 
water it is nothing beyond a thickness of '5 mm. A second ta- 
ble gives results for about 40 solid media of different kinds, of 



REPORT ON RADIANT HKAT. 3 

the same thickness ; most of them were wholly impervious to 
deirk heat ; the most remarkable exceptions being fluate of lime 
and rock salt. 

In another table are the results with black glass and black 
mica ; these substances, though diathermanous to the lamp and 
incandescent platina, are wholly impervious to the rays from 
hot water, and nearly so to those from heated copper. 

The discover}^ of the entire diathermancy of rock salt has 
been before referred to, and has furnished the means of prose- 
cuting the author's yet more remarkable researches on the Re- 
fraction OF Heat. 

TothisimportantpointM.Mellonidevotes apcrtion of the same 
memoir. After a sketch of previous attempts to establish this 
property, he describes his successful experiment by concentra- 
ting to the focus of a rock-salt lens the rays of dark heat from 
hot copper and hot water. A similar lens of alian produced 
no effect ; this proves that the effect is not due to the mere heat- 
ing of the central part of the lens. 

He next advances to the refraction of heat by a rock-salt 
prism ; describing an apparatus for the purpose. That the ef- 
fect is not due to secondary radiation, is shown by turning the 
prism on its axis into a different position, when no effect is 
produced. 

He then discusses the " properties of the calorific rays imme- 
diately transmitted by different bodies." Under this head are 
detailed one of the most remarkable species of effects which the 
whole range of the subject presents. 

The raj's of the lamp were thrown upon screens of different 
substances in such a manner, that either by changing the di- 
stance, or by concentration with a mirror, or a lens of rock salt, 
the effect transmitted from all the screens was of a certain con- 
stant amount. This constant radiation was then intercepted 
by a plate of alum, and it was found that very different propor- 
tions of heat xvere transmitted by the alum in the different cases. 
This very singular result is established by numerous detailed 
experiments, of which a tabular statement is given, and the au- 
thor states it in the following terms : "Me calorific rays issuing 
from the diaphanous screens are therefore of different qualities^ 
and possess, if tve may use the term, the diathermancy peculiar 
to each of the substances through which they have passed." 

He next investigates the effects of different colours in glass 
on the absorption of heat. He infers in general that the colour- 
ing matter diminishes the power of transmission, and examines 
the question, does it stop only rays of a definite refrangibility 
analogous to what happens in the absorption of light? 



6 RKPORT — 1840. 

With this view (following a similar mode of operation to that 
adopted in the last instance) he used successively glasses of 
different colours, for each of which the distance of the source 
was varied till a standard effect (about 40° deviation of the 
needle) was produced on the galvanometer. In this position, in 
each case, a plate of sulphate of lime was then interposed, and 
diminished the deviation to about 18° for all the coloured glasses 
except green, in which case it was to about 8°. When alum 
was substituted the deviations were reduced in the first case to 
8°, in the second to l^-G. Hence he conchules that all the co- 
loured glasses, except green, produce no " elective action" on 
heat; green glass, on the contrary, transmits rays more easily 
stopped than the others. 

Connecting this with his other inference, that rays are 
stopped in proportion to their refrangibility, he instituted 
another series of experiments to put this to the test. The 
sources of heat compared were an argand lamp and incandescent 
platiiuim, the rays of heat from the former being the more 
refrangible. Tlie quantities of heat from the lamp and the 
metal transmitted by the green glass were nearly equal ; by all 
the others, nearly in the ratio of 2 to 1. Hence he infers that 
green glass is more diathermanous for rays of less refrangibility. 

Again, the rays transmitted by citric acid and some other 
substances, are those only of the greatest refrangibility. They 
should, therefore, be the least transmissible by green glass. 
This was found to be the case. Of 100 rays passed through 
citric acid, all the other glasses transmitted various preparations, 
from 89 to 28, while green glass transmitted only from 6 to 2. 

Without the citric acid, the rays from incandescent platinum 
were more copiously transmitted by the green glass than by the 
others. 

The M^hole of the rays of low refrangibility emitted by the 
platinum, and for which alone the green glass is transparent, 
had been stopped by the interposition of the plate of citric 
acid, which had, as it were, sifted it free from these rays. 

Hence the author concludes, that " green glass is the only 
kind which jiossesses a colouration /or heat {if tee may use 
the exjnession), the others acting upon it only as more or less 
transparent glass of uniform tint does apon light." 

In a subsequent part of the memoir, M. Melloni gives a 
tabular view of the effects observed in the same manner, of the 
constant radiations emitted from six different substances, each 
intercepted successively by 24 minerals and 10 coloured 
glasses ; from which it appears that the transmission is very 
different, according to the nature of the first medium. 



REPORT ON RADIANT HKAT. J' 

He afterwards describes an experiment with the solar rays 
transmitted by a green gkiss, and then intercepted by other 
media. They pass copiously through rock salt, but feebly 
through alum. Hence he concludes, that there are arnong the 
solar rays some luhich resemble those of terrestrial heat ; and 
in general, that " the differences observed between solar and 
terrestrial heat, as to their properties of trans7nission, are 
therefore to be attributed merely to the mixture in di^'erent 
proportions of these several species of rays." 

In a note to this memoir, M. Melloni refers to my original 
experiment (Phil. Trans. 1825), in which the action of the rays 
on surfaces is observed in connexion with their transmissi- 
bility. 

He confirms the accuracy of my result, by a careful repe- 
tition of the experiment with the thermo-multiplier, but makes 
no reference to the conclusion I had drawn, viz. the co- 
existence of two distinct sorts of heat in the radiation from 
luminous sources, one of which is the same as that from dark 
sources. He explains the result by supposing the transmitted 
rays to acquire, in and by the act of transmission through the 
glass screen, new properties in their relation to the surfaces on 
which they fall, i. e. to the degree of absorption they undergo 
respectively on a black and a white surface. 

He extends the investigation by a table of results of the same 
kind with a series of screens, both transparent, and of various 
degrees of opacity. The ratio of the effects on the black and 
white surfaces is nearer to equality as the screen is more 
opake. 

On this subject there appears a short paper by M. Melloni 
in the London and Edhiburgh Journal of Science, vol. vii. 
p. 475 ; to which I replied in the same journal, Jan. 1836. 

While referring to my own experiments, I may be allowed to 
add, that in Dr. Thomson's Treatise on Heat, &c., first edition, 
the bearing of my investigation was incorrectly represented ; and 
accordingly I pointed this out in the London and Edinburgh 
Journal of Science, Nov. 1830. 

In the second edition of Dr. Thomson's work, which has 
lately appeared, the author omits all mention of the subject 
whatever. 

Transmission and Refraction of Heat : Forbes. 

The subjects of transmission and refraction of heat were taken 
up by Prof. Forbes ; and Melloni's experiments repeated and 
extended by him ; the details being given in the first and part 
of the second sections of his first Memoir " on the Refraction 



8 REIORT — 1840. 

and Polarization of Heat," read to the Royal Society of Edin- 
burgh, Jan. 5th and 19th, 1835, and published in their Trans- 
actions, vol. xiii. ; also in the London and Edinburgh Journal 
of Science, vol. vi. 

The first section contains an account of various experiments 
with the thermo-multiplier. The principal object was to vei'ify 
the several points already stated, and especially to determine 
the degree of accuracy of the instrument. From a comparison 
of its sensibility with that of air-thermometers, the author 
concludes that 1° of deviation of the needle corresponds to an 
effect indicated by about j^th of a centigrade degree. Without 
increasing the dimensions of the instrument, by which its sen- 
sibility would be impaired, he has been ena})led, by the adapta- 
tion of a small telescope, readily to measure y^th of its degrees ; 
that is, about j^o^h of a centigrade degree. 

One of the most interesting points to which the author 
directed his attention, was the possibility of detecting heat in 
the moon's rays. These rays, concentrated by a polyzonal lens 
of 32 inches diameter, and acting on the thermo-multiplier, 
gave no indication of any effect ; so that Prof. Forbes con- 
siders it certain that, if there be any, it must be less than 
^oo'oooth of a centigrade degree. 

He repeated Melloni's experiment of the refraction of heat 
hy a rock-salt prism, and was enabled to obtain some approxi- 
mate quantitative results, giving the index of refraction for 
heat in this substance, which was a little less than that for 
light. 

In the course of his second section he describes fui'ther 
experiments relative to the question discussed by Melloni, of 
the separation of the effects due to heat and light, especially 
the peculiarity (before mentioned) attending green light : he 
tried flames variously coloured with salts — giving red, yellow, 
green, and blue light ; but found the proportions of rays trans- 
mitted by alum, glass, and rock salt to be nearly constant for 
each substance. 

To this part of the subject Prof. Forbes again directed his 
attention, in a later series of experiments, in which he has 
obtained numerical results of the highest value. These are 
detailed in the last part of his third series of Researches on 
Heat, read before the Royal Society of Edinburgh, April 16, 
1838, and published in the Transactions of that body, vol. xiv. 
To the earlier portion of this memoir we shall refer, under 
another division of this report. 

The third section relates to the Index of refraction for heat 
of different kinds, as compared with that for light in the same 



REPORT ON RADIANT HEAT. i* 

medium. The method of observation adopted is indirect, turn- 
ing upon the determination of the critical angle of total inter- 
nal reflexion. This was ascertained in a rock-salt prism, having 
two angles of 40°, and one of 100°. The sentient surface of 
the pile is so placed with regard to the prism, that it continually 
receives rays coming from the source of heat, after undergoing 
two refractions and one reflexion, whatever be the angle of 
incidence, which is effected by a very simple but ingenious 
mechanical construction. Every kind of precaution to avoid 
error was adopted. And in this way the author obtained a 
series of indices " for the mean quality of the heat most abun- 
dantly contained in the rays obtained from various sources." 
These values are given in a table, and are professedly but ap- 
proximate. Prof. Forbes has, however, subsequently favoured 
me with an unpublished communication, in which he states, 
that while the numbers may be regarded as relatively correct, 
in order to become absolutely so, they must all be reduced by 
about "05. This will give the corrected series of results as 
follows : — 

o <• Tj 4. Index of refraction for 

Source of Heat. ^^^^ g^j^_ 

Locatelli lamp 1*521 

Do. transmitted through alum .... 1'548 

■ -glass .... 1-537 

opake glass . . 1*543 

opake mica . . 1'533 

Incandescent platina 1*522 

Do. transmitted by glass 1*538 

opake mica . . . 1*534 

Brass at 700° 1*518 

Do. transmitted by clear mica . . . 1*527 

Mercury at 450° 1*522 

Mean luminous rays 1*552 

From the experiments described in this section, the follow- 
ing general conclusions are deduced : — 

1. The mean quality, or that of the more abundant propor- 
tion of the heat from different sources, varies within narrow 
limits of refrangibility. 

2. These limits are very narrow indeed, where the direct 
heat of any source is employed. 

3. All interposed media (including those impermeable to 
light), so far as tried, ?'aise the index of refraction. 

4. All the refrangibilities are inferior to that of the mean 
luminous rays. 



10 REPORT~1840. 

5. The limits of dispersion are open to further inquiry; but 
the dispersion in the case of sources of low temperature ap- 
pears to be smaller than in that from luminous sources. 

Reflexion of Heat : Melloni. 

A short paper, by M. Melloni, entitled "Note on the Reflexion 
of Heat," was read to the Royal Academy of Sciences, Nov. 2, 
1835, and published in the Ann. de Chim. ix. 402, of which a 
translation appears in Taylor's Sci. Memoirs, Part III. p. 383. 

After referring to the experiments of Leslie, to show that the 
reflexion of heat depends materially on the texture, polish, &c. 
of the reflecting surfaces, he proceeds to consider what 
takes place in diathermanous substances, as in rock salt ; where, 
there being no absorption, the difference of the heat trans- 
mitted gives the quantity reflected at the first and second sur- 
faces. With other media — as glass, rock crystal, &c. — very 
thin plates exercise no sensible absorption : hence heat, after 
traversing a thick plate, being intercepted by a very thin plate, 
the loss which this occasions is due solely to the two reflexions. 
These considerations aff'ord the means of estimating the inten- 
sities of reflected heat from different substances ; and the 
author, in conclusion, gives a comparative statement of the 
reflexions from rock crystal and copper. 

Analogies of Light and Heat : Melloni and Forbes. 

M. Melloni's *' Observations and Experiments on the Theory 
of the identity of the Agents which produce Light and Heat," 
were read to the Academy of Sciences, Dec. 21, 1835, pub- 
lished in the Ann. de Chimie, No. 50, p. 418, and translated 
in Taylor's Scientific Memoirs, Part III. p. 388. 

In this paper the author combats the views of M. Ampere, 
who had proposed some ingenious speculations for explaining, 
on the theory of undulations, the identity of light and heat, 
the difference of effect being dependent solely on the different 
wave-lengths ; those producing heat being supposed longer 
than those giving rise to light. Athermanous media, such as 
v/ater, intercept tlie longer waves, but not the shorter. Thus 
the aqueous humour of the eye prevents the retina from being 
affected by heat as well as light. 

The author admits that many phasnomena may be sufficiently 
accounted for by the mere supposition of the difference of 
wave-lengths; but he mentions some experiments in which he 
thinks decisively that this Avill not hold good. 

The spectrum formed by a rock-salt prism gives the maxi- 
mum of heat considerably beyond the red end. On intei-posing 



REPORT ON RADIANT HBAT, 11 

water of increasing thickness, the maximum successively occurs 
in the red, and thence upwards to the green. A similar effect 
is produced by colourless glasses ; but with coloured glasses, 
whilst the luminous spectrum is variously absorbed and altered, 
the place of the maximum of heat remains unaltered, and the 
decrease from it quite regular. 

Another experiment consists in interposing a diaphanous 
body, which absorbs all the calorific, but only a part of the 
luminous rays. On using in this way a peculiar species of 
green glass coloured by oxide of copper, the greenish light 
transmitted " exhibits no calorific action capable of being ren- 
dered perceptible by the most delicate thermoscopes, even ivhen 
it is so concentrated by lenses as to rival the direct rays of the 
swt in brilliancy." 

On these points Prof. Forbes has made some remarks in the 
London and Edinburgh Journal of Science, March, 1836. 

Such experiments as these, he justly observes, and indeed 
many more simple, clearly show that heat is not light, but 
nothing more. It is a question, then, what is the point really 
aimed at in these speculations. The author agrees with Mel- 
loni in the result, " that one and the same undulation does not 
invariably impress the senses of sight and feeling at once. The 
great difficulty is this — to account for the equal refrangibility 
of two waves having different properties." 

New Phcenomena of Trans?nission : Melloni and Forbes. 

It appears by the Comptes Re?idus, that on September 2nd, 
1839, M. Arago communicated to the Academy of Sciences a 
letter by M. Melloni, containing some new and highly interest- 
ing experiments on the transmission of radiant heat. He found 
that rock salt acquires, by being smoked, the power of transmit- 
ting most easily heat of low temperature, or of that kind which 
is stopped in the greatest proportion by glass, alum, and (ac- 
cording to his view) all other substances. 

Upon this point, Prof. Forbes was led to some further con- 
siderations, and thence to fresh series of researches " On the 
effect of the mechanical Textures of Screens on the immediate 
Transmission of Radiant Heat," an account of which he com- 
municated to the Royal Society of Edinburgh, Dec. 16, 1839. 

Upon the above-mentioned result of Melloni, Prof. Forbes 
remarks, that according to the conclusions indicated in his own 
Researches (third series), Melloni's view of the interception of 
heat of low temperature by all substances alike, is equivalent to 
saying that substances in general allow only the more refrangi- 
ble rays to pass, or that while rock salt presents the analogy of 
white glass, by transmitting all rays in equal proportions, every 



12 REPORT 1840. 

other substance hitherto examined acts on the calorific rays, as 
violet or blue glass does on light, absorbing the raj's of least 
refrangibility, and transmitting only the others. And to this 
rule Melloni now makes out the first exception, or the first ana- 
logue of red glass, to be rock salt, having its surface smoked. 

Now Prof. Forbes, in his third series, had also pointed out 
another substance having the same property, viz. mica split by 
heat. In March, 183S, he had established, by repeated experi- 
ments, that the previous transmission of heat through glass, 
far from rendering it less easily absorbable by mica in this 
state, had a contrary effect ; and also that heat of low tempera- 
ture, wholly unaccompanied by light, was transmitted almost as 
freely as that from a lamp previously passed through glass. 

Mica not laminated possesses no such property ; hence the 
effect is due to the peculiar mechanical condition of the sub- 
stance : and hence it occurred to the author, that the effect of 
smoking the rock salt was owing merely to a mechanical change 
in the surface ; he therefore proceeded to try the effects of sur- 
faces altered by mechanical means. 

The surface of rock salt being roughened by sand-paper, it 
transmitted non-luminous heat more copiously than luminous. 
Mica similarly scratched showed the same result. 

This effect is not attributable to differences in the proportions 
of heat reflected, for in this respect, at a polished surface, all 
kinds of heat are alike, as he had before shown ; whilst by 
dii-ect experiment, he found that, at least for the higher angles 
of incidence, reflexion is most copious from rough surfaces for 
heat of low temperature, or the same kind which is most freely 
transmitted ; proving incontestably, that the stifling action of 
rough surfaces is the true cause of the inequality. 

That there is a real modification of the heat in passing through 
a roughened surface, as well as through laminated mica, and the 
smoky film, appears from some direct experiments on heat sifted 
by these different media ; which, when transmitted by any one 
of these, is found in a fitter state to pass through each of the 
others ; and this modification is the more perceptible as the cha- 
racter of the heat is more removed from that which these media 
transmit more readily ; that is, as the temperature of the source 
is higher. The following results were stated : — 

Heat from lamp through Rays out of 1 00 

smoked rock salt. transmitted. 

Direct , 36 

Previously sifted by another plate of smoked rock salt. 44 

do. do. laminated mica • 44 

do. do. rouirhened salt . 404 



REPORT ON RADIANT HEAT. 13 

The author then proceeded to try the effect of Jine iviregaiue 
and fine gratings of cotton thread ; but no difference could be de- 
tected corresponding to the different kinds of heat ; in every case 
the interception was proportioned to the fineness of the gauze. 
When fine poivders were strewed between plates of rock-salt, 
or fine lines were ruled upon the surface, or the surface tar- 
nished by mere exposure to the air, the easier transmission of 
heat of low temperature was rendered apparent. 

These effects the author considers as evidently pointing to 
phoenomena in heat, resembling diffraction and j}eriodic co- 
lours in light. 

Such v\ as the general sketch of his researches which Prof. 
Forbes gave at the period above-mentioned. Subsequently (up 
to March 1840) he continued engaged on the same subjects, 
and on May 15, 1840, laid before the council of the Royal So- 
ciety, Edinburgh, a more extended account of the entire inves- 
tigations, which appears in vol. xv. Part I. of their Transac- 
tions, under the title of "A Fourth Series of Researches on 
Heat." Some remarks by M. Melloni appear in the Comptes 
Rendus, March 30, 1840, on the same subject. 

For obtaining a general view of these results, the main point 
to be kept in sight is the relation which the transmissibility of 
each sort of heat appears to bear to its refrangibility ; and hence 
the analogy of diathermanous media, which transmit the less re- 
frangible heat, to transparent media, which transmit the red 
rays of light, the transmission of the more refrangible heat being 
analogous to that of violet light. 

Upon this important point Prof. Forbes enlarges in the in- 
troductory part of his memoir ; he justly observes that such a 
generalization carries us forward a step, by teaching us to refer 
to the quality of refrangibility certain pi-operties of heat, which 
before were connected only with certain vague characters in the 
nature of the source whence it was derived. Among other 
things, we find, what was long suspected, but what Melloni first 
conclusively proved, that it does not essentially depend on the 
presence or absence of light. This refers to his singular dis- 
covery of the change produced by the intervention of certain 
screens. 

Heat from a7iy source, if it admit of transmission at all 
through glass, alum, or water, will ultimatelj^ have the character 
of glass-heat, alum-heat, or water-heat, just as light from the 
sun, or from a candle, becomes red, blue, or green, by trans- 
mission through glasses of those colours. 

The author gives, as an illustration, the following scale of 
different kinds of heat, in the order of refrangibility, beginning 
with the lowest : — 



14 REPORT — 1840. 

1. Heat from ice. 

2. the hand. 

3. boiling water. 

4. a vesselof mercuryunderitsboilingtemperature. 

5> metal smoked; — wholly non-luminous in the 

dark, heated by an alcohol-lamp behind it. 

6. Heat from incandescent platina (over a spirit-lamp). 

7- an oil-lamp (direct). 

8. Oil-lamp heat transmitted by common mica. 

9. glass (argand lamp). 

10. citric acid. 

11. alum. 

12. ice. 

Melloni having shown that a portion of the heat from a lumi- 
nous source is transmitted through certain screens, which are 
wholly opake to light, it became natural to inquire vvhether the 
rays so passed possessed the properties of heat from dark sources. 
This he found to be partly the case, and partly not. 

The direct test of examining the refrangibility of the heat- 
rays issuing from the screen occurred to Prof. Forbes, who found 
that opake glass and mica act as clear glass and mica do in ele- 
vating the mean refrangibility of the transinittcd heat, an ac- 
tion analogous to that of yelloiv glass upon light. (See 3rd 
Series, Art. 73, 81, &c.) 

But in all this there was nothing exactly equivalent to the 
action of red glass ; this, however, was discovered by Melloni, 
by the happy suggestion of covering the surface of rock salt 
with smoke. 

These remarks introduce more clearly the main object of 
Prof. Forbes in following up the inquiry. In the pi-esent paper 
the details of many series of experiments are given, and the 
more precise results now established may be stated as follows : 

I. The peculiar character of the film of smoke on the surface of 
adiathermanous medium, analogous to redness in glass for light, 
was found to be possessed by — 1. The simple powder of char- 
coal. 2. Some other dull earthy powders. 3. Surfaces simply 
dull, or devoid of polish. 4. Surfaces irregularly furrowed, as 
with emery or sand-paper. 5. Polished surfaces, on which fine 
distinct lines have been drawn. 6. Transparent mica, when 
mechanically laminated, which, as a continuous medium, pos- 
sesses opposite properties. 

II. All kinds of heat (i. e. of all refrangibilities) seem affect- 
ed indifferently by the following media : — 

1. The thinnest leaf-gold, which is i?nj)ervioiis to any kind of 
heat. 

2. Fine metallic gratings, which transmit all kinds of heat 



REPORT ON RADIANT HEAT. 15 

in a proportion probably exactly that of the areas of their inter- 
stices. 

3. Thread gratings. 

4. Most crystalline bodies in a state of powder, in which case 
they approximate to a condition of opacity for heat. 

III. The following substances, in addition to those before 
known, transmit most heat of high temperature or high refran- 
gibility, analogous to violet light : — 

1. Several pure metallic powders. 2. Rock salt, in powder, 
and many other powders. 3. Animal membrane. 

IV. Heat of low temperature is most regularly reflected at 
imperfectly polished surfaces. It is also, as has been shown 
above, most regularly transmitted. These facts are in them- 
selves very remarkable, and especially so with reference to the 
theory of heat, and its analogies to that of light, particularly 
with respect to absorption. Some of these considerations, which 
bear on the undulatory doctrine, are noticed by the author in 
§ 24. 

The curious question relative to the analogies of the action 
of gratings, &c., to the parallel cases in the interference of 
light, has been recently illustrated by some mathematical in- 
vestigations by Professor Kelland ; and the autlior concludes his 
memoir with some highly ingenious and interesting suggestions 
for further inquiry bearing on these topics. 

Radiation of Heat : Hudson. 

At the meeting of the British Association, 1835, Dr. Hudson, 
of Dublin, communicated some researches on radiant heat, of 
which notices appear in the Report of that Meeting (p. 163, and 
Proceedings of Sections, p. 9.) • A paper by the same author on 
the subject is printed also in the London and Edinburgh Jour- 
nal of Science, vol. viii. p. 109. 

In the paper last mentioned, besides making some critical re- 
marks on the results of Melloni and others, the author describes 
a very simple and effective mode of arranging the apparatus for 
experiments on diathermancy with the thermo-multiplier, so as 
completely to exclude the influence of secondary radiation. The 
source of heat is a canister of hot water, which can be so placed 
in two diff'erent positions that it is exactly at the same distance, 
and presents the same surface ; but in one case the pile receives 
the heat both direct and secondary ; in the other only the se- 
condary, derived from the heating of the screen. 

In his communication to the British Association the same 
author examines principally certain questions bearing on the 
supposed radiation of cold, and the theory of Leslie. These 



IG REPORT 1840. 

were peifonned by a diiferential thermometer, and a concave 
reflector, with a hollow back, so that the mirror itself could be 
heated to any required point, by filling the hollow with hot 
water. The source of heat was a canister of water, with one 
surface varnished, another metallic. 
The main results were as follows : — 

1. The mirror being at the temperature of the air, and the 
canister cooled below if, the varnished side produced a greater 
cooling effect on the focal bulb than the plain, in the same ratio 
as that in which it produced a greater heating effect when the 
canister was heated above the air. 

2. The mirror being heated to 200° Fahrenheit, and the ca- 
nister at the temperature of the air, both bulbs were so placed as 
to bo equally affected by the heat of the mirror ; when the ca- 
nister displayed a cooling effect, the varnished side being the 
most efficacious. 

3. Again, with the same conditions, except that the canister 
was heated 10° or 12° above the air, it was placed at different 
distances ; at near distances it showed a cooling effect ; at a cer- 
tain point this ceased, and beyond it, it began to produce a slight 
heating effect. 

4. Some attempts were made to try the effects while the bulb 
was kept cool by evaporation ; the canister being also cooled 
below the air, the cooling of the bulb was increased beyond 
what took place when the canister was at the temperature of 
the air. These experiments were confessedly imperfect, from 
the difficulty of regulating the evaporation. 

The author considers them as favourable to the theory of the 
radiation of cold; he also refers to them as in some degree con- 
firmatory of Leslie's view of pulsation. 

The most remarkable result is that of Case 2 ; it seems to 
prove that a mirror, when heated, will still reflect rays of heat, 
thrown upon it from a source of much lower temperature. 

The results are viewed by the author as supporting the theory 
of the radiation of cold. I believe the doctrines of that theory 
may in all cases be equally well expressed in other language, in 
conformity with the view to which I referred in my former re- 
port, p. 262. 

Dr. Hudson has speculated with much ingenuity on another 
point of great interest., the different radiating powers of different 
surfaces. Understanding by the surface a certain physical 
thickness, he conceives the radiating poiver to depend on the 
caj)acity for heat of the substance of the lamina, which seems 
perfectly conformable to the general law of the equilibrium of 
temperature. 






REPORT OX RADIANT HEAT. I/ 

Iiifluence of surface and colour 07i Radiation : Stark and Bache. 

The influence of the colour of a surface on its powers for 
absorbing and radiating heat, is a question which has long 
attracted notice, and has often been involved in no small con- 
fusion, from false analogies. The sun's rays, and, in general, 
what is called luminous heat, are absorbed b)' surfaces {cccteris 
paribus) in proportion to the darkness of their colours ; but it 
has been too hastily assumed that the same would hold good 
with non-luminous heat, and still more groundlessly, that the 
colour would influence the radiating power of the surface ; the 
texture of the surface, however, is known to exert a powerful 
influence. These distinctions are fully insisted on in my former 
report. 

Since that period, however, the subject has been taken up by 
Dr. Stark, who, in an elaborate paper in the Phil. Trans, for 
1833, details a number of ingenious experiments, which he con- 
ceives support the doctrine of the influence of colour, not only on 
the absorption of dark heat, but even on odours, miasma, &c. 

The object of the present report is not controversial ; I will 
therefore merely state, that I discussed in detail Dr. Stark's 
reasonings, in a paper published in the Edinburgh New Philo- 
sophical Journal, October, 1834, where, though allowing the 
value and accuracy of the experiments, I have expressed my 
objections to the inferences made from them. 

It appears in general that the texture and nature of the sur- 
face most unquestionably exert a great influence. Now, where- 
ever there is a difierence in the colour, there must be either a 
difi'erence in the mechanical structure of the surface, or some 
new matter added or abstracted. When therefore we consider 
the changes which thus occur, we cannot infer that the effect 
is not owing to these instead of to colour as such. The ques- 
tion, however, is a highly curious one, and worthy the most 
accurate investigation. 

Having in some measure called attention to it in my former 
report, it was with no small gratification that I found the sub- 
ject had excited interest not only in this country, but also in 
America ; and to Professor Bache (since appointed principal of 
Girard College) we owe by far the most extensive and valuable 
series of experiments on this important but difficult point of 
inquiry : they are given at length in the Journal of the Franklin 
Institute, November, 1835. 

The notices of these experiments which had been pub- 
lished in this country, not appearing to convey adequate 
notions of their nature or value, I endeavoured to bring them 
VOL. IX. 1840. c 



18 REPORT — 1840. 

more prominently forward by some remarks in the Physical 
Section of the British Association at Liverpool in 1837*. In my 
former report I had thrown out some suggestions both as to the 
want of such a series of experiments, and as to the fundamental 
difficulty arising from the variety of causes which must influence 
the results ; but more especially the difi^erences of thickness 
in the coatings, which in the ordinary iiiode of operating could 
not be estimated, yet must greatly modify the effects. 

With reference to the necessity of equalizing the coatings, 
Mr. Bache refers to an important observation of Leslie, viz. 
that radiation takes place not merely from the actual surface, 
but from a certain depth, or lamina of the surface, the thickness 
of which is quite appreciable in good radiators, and differs for 
different substances. 

Proceeding upon this fact, the author justly observes, that 
" the radiating powers of substances would not be rightly com- 
pared by equalizing their thicknesses upon a given surface, nor 
by equalizing their weight ; but by ascertaining for each sub- 
stance that thickness beyond ivhich radiation does not take 
place." 

It is then on the original application of this fundamental 
idea that his whole series of experiments is conducted. 

Upon this principle the first object was to obtain some data as 
to thicknesses of different pigments necessary to be employed. 

The method adopted throughout was to employ tin cylinders 
of the same size, filled with hot water, and having thermome- 
ters inserted through a hole in the top ; Avhile their surfaces 
were coated with the different substances under trial. The ra- 
diation was estimated by the observed rates of cooling. 

To find the critical thickness of the coating just spoken of, 
the time of cooling a certain number of degrees was accurately 
observed, first with a thin coating, then with an additional 
layer of the pigment, and so on, until it was found that addi- 
tional thickness did not increase the rate of radiation, but 
began to diminish it ; thus each coating was adjusted precisely 
to that thickness at which it produced its maximum effect. 

Every precaution to ensure accuracy appears to have been most 
diligently taken, and several series of preliminary experiments 
are recorded for the purpose of ascertaining the limits within 
which the precision of the results may be relied on. A standard 
cylinder, coated with aurum musivum (as being found not 
liable to tarnish or alteration), was used in all the experiments, 
and the effect of each coating compared with this under similar 
circumstances. 

• See Report, 1837. Sectional Proceedings, p. 20. 



RfiPORT OX RADIANT HEAT. 



19 



The results of different sets of experiments are given in the 
tabular form, and apply to coatings of a great variety of sub- 
stances differing in their chemical nature, as well as in rough- 
ness, texture and colour. The following table is extracted as 
fully exhibiting the general result of all the experiments ; the 
substances being arranged in the order of their radiating powers, 
beginning with the highest. 



Nature of Coating. 



Litmus blue. 
Prussian blue. 
Amnion, sulphate ^ 

of copper. J 

Peroxide of manga-i 

nese. J 

India ink. 

Bichromate of potash. 

India ink. 



Colour. 



Alkanet. 

Carb. of lead in oil 
of lavender. 

Sulphuret of lead. 

Alkanet blue. 

Carb. magnesia. 

Carb. lead in gum. 

Carb. of lime. 

Vermilion. 

Sulph. baryta. 

Golden sulphuret of 
antimony. 

Indigo. 

Cochineal. 

Red lead. 

Sulph. baryta. 

Plumbago. 
Chrom. lead. 
Gamboge. 
Bisulphuret of tin. 



} 



} 



Blue. 
Blue. 

Greenish blue. 

Brovniish black. 

Black. 

Brown. 

Black. 

Crimson. 

White. 

Black. 

Blue. 

White. 

_ White. 

Dingy white. 

Red. 
White bluish. 

Brown. 

Blue. 

Crimson. 

Orange. 

White. 

Black. 

Yellow. 

Olive green. 

Yellow. 

V2 ■ 



Surface. 



Rough. 
Rough. 

fNot shining, but 
\ uniform. 
Not smooth. 

r fe. Streaked: 
\smooth streaks. 

Smooth. 
/Not shining, but 
\ uniform. 
/"Smooth, not 
\ shining. 



Rough. 

Smooth. 

Medium. 

Smooth. 

Rough. 

{Smooth, in 
streaks. 
Smooth. 
Smooth. 
Smooth. 
Medium. 

{Not shining, 
but uniform. 
Smooth. 
Smooth, in 
streaks. 
Smooth. 



20 REPORT — 1840. 

It thus distinctly appears, that through so extensive and 
varied a range of differences in the state of the radiating sur- 
face, no determinate relation subsists between the radiating 
power, and either darkness of colour, or any other distinctive 
character of the coating employed ; not even its roughness or 
smoothness. 

Rejmlsive Power of Heat : Powell. 

Closely connected with the radiation of heat is its property of 
exerting or exciting a repulsive force between particles or masses 
of luatter at small though sensible distances. 

Such a property was first announced by Libri in 1824 ; and 
was further examined by Fresnel {Ann. de Chirn., xxix. 57. 
107.) and Saigey {Bull. Met h., xi. 167.), but their results seem 
to have been open to some doubt. 

A new interest attached to the subject from the reference 
made to this property by Prof. Forbes (in a paper read to the 
Royal Society of Edinburgh, March, 1833, and since published 
in their Transactions, vol. xii.) in explanation of certain vibra- 
tions of heated metals first observed by Mr. Trevelyan. 

A paper from me was read to the Royal Society, June 19,1 834, 
and printed in the Philosophical Transactions, 1 834, Part II. 
containing an account of experiments on a different principle 
from any of tlie preceding, which appeared to furnish a deci- 
sive proof of the fact of repulsion. 

The essential principle is the employment of the colours of 
thin plates, as ?i measure oi\he separation produced between two 
surfaces, by the repulsive action of heat applied to one of them. 
I also made observations on several particulars attending the 
mode of action, both in that paper, and in a communication to 
the British Association at the Edinburgh meeting*. 

Formation of Ice : Farquharson. 

An interesting case, in which the principles of the theory of 
radiant heat are related to the explanation of natural phaenomena, 
occurs in the instance of the formation of ice exclusively at the 
surface of still water, but occasionally at the bottom of running 
water. This point excited attention some years ago, and was par- 
tially discussed by Mr. Knight in the Philosophical Transactions, 
1816. Mr. MacKeevor and Mr. Eisdale subsequently investi- 
gated the theory, and M. Arago gave a discussion of the whole 
question in the Annuaire, 1833, and in the Edinburgh New Phi- 
losophical Journal, vol. xv. p. 128 ; lastly, a highly curious paper 
appeared in the Philosophical Transactions for 1835, Part II. 

* See Report, 1834, p. 549, and Dr. Thomson's Records of Science. 



REPORT ON RADIANT HEAT. 21 

" On the ice formed under peculiar circumstances at the bottom 
of running water", by the Rev. J. Farquharson, F.R.S. of Al- 
ford, Aberdeenshire. In tliis paper tlie author details various 
new and highly interesting particulars as to the mode of the 
formation of the spongy masses of spiculae of ice at the bottom 
of certain rivers in his neighbourhood, and the peculiar cir- 
cumstances under which alone it is formed. He examines acutely 
the several explanations which have been suggested, which he 
shows are all insufficient to explain the ivhole of the circum - 
stances, and then proceeds to suggest his own theory, which is 
grounded essentially on the assumption that the radiation of 
heat from substances at the bottom goes on throtigh the ivater ; 
and partly also on the supposed greater radiation from dark- 
coloured surfaces. Neither of these assumptions, it appears to 
me, are admissible ; the former especially is directly at variance 
with the experiments of Melloni. Some suggestions at least 
towards a theory not open to these objections, are given ))y an 
anonymous writer in the Magazine of Popular Science, vol. i. 
p. 157. 

Division II. — Polarized Heat. 

Polarization of Heat : Forbes. 

The original statement by Berard, of the polarization of heat 
by reflexion, and the attempts to verify it, are mentioned in my 
former report*. In 1833, Melloni tried to repeat the experiment 
with tourmalines, but unsuccessfullyf. 

In 1834, Nobili attempted it by reflexion, employing the 
thermo-multiplier, but without success J. The disbelief in such 
a result, at least wiih dark heat, seems now to have prevailed 
generally. Mrs. Somerville, in the second edition of her " Con- 
nexion of the Sciences " (in 1833), speaks of it as altogether 
without experimental proof. 

Prof. Forbes took up the inquiry in November, 1834; and in 
his first memoir, already referred to in Section 2, announced his 
complete success, after having in the first instance failed from 
the influence of secondary radiation, which disguised the real 
eff'ect. 

(1.) He proved distinctly the stoppage of a considerable pro- 
portion of heat when the tourmalines were crossed, not only 
with a lamp, but with brass heated below luminosity. 

(2.) In the third section of the same memoir, he details his 

* British Association Report, vol. i. pp. 262. 276. 

t Second Memoir, Ann. de Ckim. 55. Taylor's Scientific Memoirs, Part I. 
p. 59. + Biblioth. Univ., Sept. 1834. 



22 REPORT 1840. 

researches on the polarization of heat by refraction and re- 
flexion. In the former he employed piles of mica, and 
through these, found even dark heat very freely transmitted at 
the polarizing angle. Without (in this stage of the inquiry) 
aiming at quantitative results, he found in general that the pro- 
portion of heat polarized varied with the source in the following 
order, begining with the highest : — 

Argand lamp. 

Locatelli lamp. 

Spirit lamp. 

Incandescent platina. 

Hot brass, about 700° Fahrenheit. 

Mercury, 500° in crucible. 

Water under 200°. 
(3.) The polarization of heat by reflexion at the surface of a 
pile of plates of mica was also established ; and with regard to 
the reflexion from glass, Prof. Forbes has also remarked, that 
from the known proportions of heat reflected, the quantity, 
even at the maximum which would reach the thermoscope after 
two reflexions, would be so extremelj^ small, that no difference 
of effect in the two rectangular positions could really have been 
perceptible in the form of the experiment adopted by Berard. 

(4.) In the fourth section the author enters on the modifications 
which polarized heat undergoes by the intervention of crystal- 
lized plates between the polarizing and analysing parts of the 
apparatus ; an inquiry suggested by the obvious analogy in the 
case of light. In the crossed position, when polarized heat is 
stopped (if the analogy hold good), the intervention of a plate 
of double refracting crystal would restore the effect. This 
apparently paradoxical result was fully verified with plates of 
mica, and subsequently with selenite and other substances, not 
only in the case of luminous sources, but even with water be- 
low the boiling temperature. Of 157 experiments with three 
different mica plates, only one gave a neutral and one a negative 
result. Of these 157, 92 were made with heat below luminosity. 
The apparent paradox was increased by the circumstance 
that a thin plate of mica which " depolarized" but feebly 
seemed to stop more heat than a thick plate which depolarized 
more completely. 

The main fact was ascertained for the first time on Decem- 
ber 16, 1834. The Professor justly censures the use of the 
term "depolarize," and suggests " (//polarize" as preferable. 

(5.) From the result thus unequivocally established, a train 
of highly curious consequences follow. We have hence, as 
direct corollaries, the double refraction of the rays of heat by 



REPORT ON RADIANT HEAT. 23 

the mica, and their interference according to the same laws as 
those of light. Hence also follow the constancy of the sum 
of the intensities of the rays in the rectangular positions, or 
their complementary character, agreeably to the formulas of 
Fresnel for light. This again involves their retardation, ac- 
cording to the well-known principles of the undulatory theory ; 
and hence from Fresnel's formulas we are assured theoretically 
of the existence of circular and elliptic polarization in the rays 
of heat, under the appropriate conditions : we have thus also 
the means of deducing the length of a wave of heat. 

The whole of this most important series of investigations 
was completed between November ] 834 and January 1835, and 
their originality and priority are thus placed beyond dispute. 
The main practical improvement (which led to all the rest of 
the discoveries) was the employment of the piles of mica for 
polarizing the heat. In the summer of 1835, Prof. Forbes was 
at Paris ; and finding both M. Biot and M. Melloni sceptical 
as to his results, he exhibited them with mica piles, which he 
himself prepared on the occasion, and which he left in M. Mel- 
loni's hands. 

In these experiments the utmost care was taken to guard 
against all the sources of fallacy from secondary radiation, &c. ; 
but as Prof. Forbes observed, these always tended to disguise 
and not to exaggerate the results. One consideration of this 
kind arising from the mere mathematical question of the dif- 
ferent amovmt of heat which might be radiated from one pile to 
the other in the two rectangular positions (regarded merely as 
a mathematical problem), was proposed by myself at the Dublin 
meeting of the British Association, 1835, but was completely 
shown to be inapplicable as a practical objection by Prof.Forbes, 
in a short paper in the London and Edinburgh Journal of Sci- 
ence, November, 1835 ; and further by direct experiment de- 
scribed in the same Journal for March, 1836. 

Circular and Elliptical Polarisation of Heat : Forbes. 

On the 1st of Feb. 1836, Prof. Forbes announced to the Royal 
Society of Edinburgh, that he had that day succeeded in esta- 
blishing the circular polarisation of heat, even when unaccom- 
panied by light, by direct experiment. It has been already 
noticed, that theoretically this would follow from the laws of 
depolarization. But in the present instance. Prof. Forbes, fol- 
lowing up the analogies of Fresnel with regard to the internal 
reflexion of light, found the very same thing verified with heat 
by similar internal reflexion in a rhomb of rock salt, where the 



24 REPORT — 1840. 

plane of reflexion is inclined 45° to the plane of primitive 
polarization. 

A short notice of this discovery appears in a paper by the 
author, in the London and Edinburgh Journal of Science, 
March, 1836, in which he also states the inference from the 
same considerations, that the waves are of the same Jcind as 
those of light, viz. formed by transverse vibrations. 

In a paper reported in the Proceedings of the Royal Society 
of Edinburgh, March 21, 18.36, and printed along with the 
second series of Prof. Forbes's Researches in the London and 
Edinburgh Journal of Science, vol. xii., that philosopher de- 
scribes some additional results which he has obtained respect- 
ing the polarization of heat. These are briefly as follows : — 

1st. Heat polarized in any plane, and then reflected from the 
surface of a refracting medium, changes its plane of polariza- 
tion in a manner similar to what obtains in light ; that is, the 
plane is on one side of the plane of reflexion up to the maxi-- 
mum polarizing angle, and on the other side after passing that 
limit. This mode of determining the polarizing angle off'ers 
some advantages ov^er the more direct methods. 

2ndly. Metals polarize heat very feebly by reflexion. Yet 
the eff"ect is perceptible, and increases, through a considerable 
range of incidences, but it does not seem to attain a maxi- 
mum ; in this respect it seems to agree with what Sir D. 
Brewster has remarked in light, viz. that the maximum is 
greatest for the least refrangible rays, heat being less refrangible 
than light. 

3rdly. Heat polarized in a plane inclined 45° to the plane of 
reflexion at silver, has its nature changed, as in light, and pre- 
sents the conditions of elliptic polarization, though the ellipse 
is much more elongated. 

4thly. Two reflexions from silver increase the polarizing 
effect of metals, and an increased tendency to circular polariza- 
tion under the conditions of the last case. The effect increases 
with the obliquity of incidence. 

All these results have been verified in the case of obscure as 
well as luminous sources of heat. 

On the 15th Feb. 1836, the Keith prize was awarded to 
Prof. Forbes by the Royal Society of Edinburgh ; the Vice- 
President, Dr. Hope, stating, in the course of a most able 
address delivered on the occasion, that several members of the 
council, as well as himself, had personally witnessed the satis- 
factory verification of the main facts announced, before the 
medal was adjudged. 



REPORT ON RADIANT HEAT. 25 

Polarization of Heat from different sources: Melloni. 

M. Melloni's first memoir " On the Polarization of Heat," was 
read to the Academy of Sciences in Jan. 1836; it appears in 
the Ann. de Chim. Ixi. April, 1836 ; and is translated in Tay- 
lor's Scientific Memoirs, Part II. p. 325. 

The author commences with a fair review of the previous in- 
vestigations on the subject, admitting Prof. Forbes's discovery, 
but remarking the very small amount of the effect in the case 
of obscure heat. 

He adopts the supposition, that " the different temperatures 
of the calorific rays are to radiant heat what the different 
colours of the luminous rays are to light." The latter, he 
observes, are all equally polarizable, and thus he is led to regard 
the difference of polurizability in the rays of heat as rather 
apparent than real. His object then, in this memoir, is to 
examine the question of the reality of the polarization of heat, 
and of the equality of the effect in different sorts of heat. 

After some considerations on the general nature of the appa- 
ratus to be employed, and overcoming the difficulty arising 
from the small total intensity of the rays, by concentrating them 
by means of a rock-salt lens, he proceeds to detail his several 
series of experiments, the results of which he gives in the 
form of tables : — 

Table I. gives the different indices of polarization obtained 
with nine sorts of tourmalines of different colour, the source of 
heat being a locatelli lamp. 

He then tried the experiment, taking that pair of tourmalines 
which gave the greatest effect in the last set, with plates of 
various substances interposed between the lamp and the appa- 
ratus. Of these, opake black glass rendered the effect nearly 
insensible ; other solids and liquids of various degrees of trans- 
parency produced effects of different magnitude. 

In Table II. these results are registered, and the properties of 
the media, in this respect, were found to follow the same pro- 
portion as their diathermancy. 

The author considers the difference of the tourmalines in this 
respect as referrible to the same cause. 

Table III. gives similar results with another pair of tourma- 
lines, in which case the proportions are found to differ. 

In Table IV. are given the indices of polarization with four 
different pairs of tourmalines, each employed with different 
sources of heat ; viz. the locatelli lamp, argand lamp, incan- 
descent platina, and copper at 400°. The effect in the latter 
case was very small. 



26 REPORT 1840. 

In recapitulating his views, the author refers to the unequal 
ahsorption of the two pencils in different tourmalines, as cau- 
sing the differences observed. 

A further paper by the same author, on Tourmaline, &c., in 
the Ann. de Chim., April, 1836, displays much ingenuity, but 
nothing of peculiar novelty or fundamental importance. 

From the Comptes Rendus, 1836, i. 194, it appears, that 
on the 15th Feb. 1836, M. Arago communicated to the Aca- 
demy of Sciences a letter from Prof. Forbes, announcing his 
discovery of the circular polarization of heat of the rock-salt 
rhomb. 

At the next meeting of the same body (Feb. 22), MM. Biot 
and Melloni stated, that in following up Prof. Forbes's experi- 
ment, they had found that quarts possessed the scijne "rotative" 
quality for heat as for light. 

Dr. Thomson, in the second edition of his Treatise on Heat, 
&c. (1840), while giving an outline of the discoveries of Forbes 
and Melloni, has by no means clearly distinguished the share 
borne by each of those philosophers in the investigation. In 
particular, with respect to the fact of polarization, he has not 
given Prof. Forbes the credit so unquestionably due to him for 
the priority of the discovery. He observes (p. 139), " In the 
earlier experiments of Melloni, he did not find that the rays of 
heat were polarized when passed through the tourmaline. But 
he afterwards found that this conclusion was hasty, and that 
the tourmaline polarizes heat as well as light. The truth of 
this statement is shown very clearly by Prof. Forbes. They 
also polarized heat by plates of mica, and also by reflexion," &c. 

These expressions certainly assign the priority to Melloni, as 
well as an equal share in the subsequent results ; both of which 
we have seen are greatly at variance with the truth. 

Further Researches : Forbes. 

Prof. Forbes's second series of Researches on Heat was read 
to the Royal Society of Edinburgh, May 2, 1836, and printed 
both in the Edinburgh Transactions, vol. xiii., and in the London 
and Edinburgh Journal of Science, vol. xii. 1838. 

The author remarks at the outset, that in his former memoir 
he had confined himself to the establishment of the general 
facts of the polarization and rfipolarization of heat, without pre- 
tending to accurate quantitative results ; he now proceeds, there- 
fore, to a more detailed investigation of the subject, with a view 
to more precise numerical determinations. 

The first section relates to the methods of observation em- 
ployed, and the examination of the values of the degrees of the 



REPORT ON RADIANT HEAT. 27 

galvanometer, which, for the most part, do not indicate equal 
increments of force. Two tables are given. By the first, the 
statical deviations of the needle are reduced, so as to be mea- 
sures of the force producing them ; by the second, the dynami- 
cal effect, or arc, moved over by the initial disturbing action, is 
reduced to the final or statical effect, and thence to the true 
measure of heat. Several peculiarities attendant on the use of 
the galvanometer are likewise discussed. 

In section 2, the observations formerly published on the 
polarizing action of tourmaline are confirmed, including the 
case where heat, entirely unaccompanied by light, was em- 
ployed. In this case, the author allows, the greatest difficulty 
was to be encountered. 

The third section treats of the laws of the polarization of 
heat by refraction or transmission. Prof. Forbes expressly 
observes, that his former results were not held out as numeri- 
cally precise ; and with reference to Melloni's conclusion, " that 
all kinds of heat are equally polarizable at the same incidence," 
he confirms his former view of the incorrectness of this infer- 
ence by a great number of experiments, which show that the 
heat from non-luminous sources is less polarizable by a given 
plate of mica, at a given angle of incidence, than that accom- 
panied by light. 

These experiments were performed with plates of mica, pre- 
pared in a way discovered by himself, to which reference is 
made (though without describing the process), in a paper before 
quoted in the London and Edinburgh Journal of Science, March, 
1836. The method consists in applying sudden heat to a thick 
plate of mica, which splits into an infinity of extremely thin 
films, so thin as to be incapable of retaining heat ; these form 
polarizing piles of great energy. With one pair of such plates 
the author obtained the following per centages of heat stopped, 
when the planes of refraction of the two plates were in the 
rectangular position : — 

Source of Heat. Rays out of 100 Polarized. 

Argand lamp 72 to 74 

Incandescent platina 72 

Brass about 700° 63 

Do. with glass screen 72 

Mercury in crucible at 410° . . . 48 

Boiling water 44 

These observations were repeatedly made, and verified by 
others with other pairs of plates. The results agree with the 
analogy of light ; those lowest in the scale being the cases of 
the least refrangible rays. 



28 REPORT 1840. 

In the fourth section the law of polarization by reflexion is 
discussed. A number of reflecting surfaces were tried, and 
split mica was preferred. The amount of polarization by re- 
flexion at a given angle, is shown to vary with the source of 
heat ; and it is probable that the kinds of heat do not rank in 
the same order when the angle is changed. This is the case 
with light. The change of the plane of polarization by subse- 
quent reflexion, is similar to that which occurs when light is 
used. 

The circular polarization of heat by total internal reflexion, 
is discussed in the fifth section. This, as before remarked, is 
a phftnomenon really produced in the experiments on dipolari- 
zation, if the mica be of a suitable thickness. The direct ex- 
periment with rhombs of rock salt, has been already mentioned 
also. The author here gives a detailed account of them, and 
the laws of the phcenomena deducible, in which the precise 
analogy with those of light is preserved. 

Equal Polarizability of Heat from different sources : 
Melloni. 

Melloni's second memoir on the Polarization of Heat appears 
to be foimded on the second part of his communication to the 
Royal Academy of Sciences in January, 1836. It is printed in 
the Atm. de Chitn. Ixv. May, 1837, and the translation in Tay- 
lor's Scientific Memoirs, Part VI. 

The principal points of these extensive researches may be 
reduced to the following heads : — 

(1.) Referring to Prof. Forbes's Researches, first series, Mel- 
loni contends that the difi^erences of polarizability in the heat 
from different sources there exhibited, are in fact due to differ- 
ences of secondary radiation from the heating of the mica piles, 
and subsequently appeals to Forbes's second series, in which he 
conceives the approach to equality is much nearer, as this 
source of error was more avoided. 

At lower temperatures of the source, he observes, that mica 
transmits less heat in pi'oportion, and therefore absorbs more : 
thus the secondary radiation is greater, and the apparent dif- 
ference in the two positions, or index of polarization, is less. 

(2.) He remarks, that Prof. Forbes had found the heat from a 
dark source, after transmission through glass, to become as po- 
larizable as that from incandescent platina; whereas he considers 
that the glass plate absorbed the greater part of those rays 
which otherwise would have heated the piles, and that thus the 
apparent polarization was increased. 

(3.) Melloni describes his apparatus, and the precautions for 



REPORT ON RADIANT HEAT. 29 

avoiding secondary radiation, ^c, employing piles of sjjUt 
mica, and throwing parallel rays on them by means of a rock- 
salt lens, having its principal focus at the source of heat. 

He then enters upon the details of his results, in several 
series, with piles of different numbers of laminae, and at dif- 
ferent inclinations to the axis (the source of heat being a lamp), 
giving in each case the calorific transmissions in the rectangular 
positions, or proportions of heat polarized. These are com- 
prised in a series of eight tables, from which the author derives 
the following conclusions : — 

I. The proportion of heat polarized increases as the inclina- 
tion of the piles is diminished. 

II. It attains a maximum at a certain inclination. 

III. This inclination is greater as the number of laminae is 
increased. 

He points out the close agreement of these results with the 
phaenomena of light according to Brewster and Blot. 

(4.) The author pursues a further series of experiments on 
polarization by reflexion, and arrives at the conclusion that the 
angle of complete polarization by reflexion is very nearly the 
same for light and for heat. 

(5.) If any diathermanous substance be interposed between 
the luminous source and the piles, the index of polarization 
does not vary with the substance employed. 

This, he contends, proves that the nature of the heat does 
not alter its polarizability. 

But also from direct experiment with the radiations from 
different sources, he makes the same inference, employing, in- 
stead of a lamp, incandescent platina, metal heated to 400°, or 
boiling water, with the same results of uniform polarizability. 

He maintains that the difference of polarizability by refrac- 
tion, arising from the different refrangibility of the rays of heat, 
is too minute to be sensible. 

And for all experiments on obscure heat he proposes to sub- 
stitute as the source a black glass heated by flame. 

(6.) On the depolarization he refers to Forbes's experiments, in 
which he contends the difference in the rectangular position is 
very small, but nearly equal with different sources. 

He repeats the experiment, with black glass interposed, and 
finds the effects much greater, and nearly equal in the different 
cases. 

He endeavours to explain Forbes's result of the difference 
with dift'erent sources, by secondary radiation. 

Further, by the same method (of interposing a black glass), 
he finds the equal depolarizability of every kind of heat. 



30 REPORT 1840. 

In an attempt to pursue the analogy of the tints of depolar- 
ized light, he acknowledges a failure, and thence considers the 
interference of calorific rays as not yet proved. 

Upon these investigations the following remarks may be 
offered : — 

Under the first head, it should be recollected that Prof. 
Forbes's first memoir, was avowedly only directed to ascertain 
general facts, not numerical values ; while, with regard to the 
more precise results of the second memoir, it would appear from 
the details there given, that the secondary radiation could not 
affect the residts. The screen between the source and the piles 
was removed only during the few seconds required for observing 
the first or impulsive arc of vibration, the time of which was 
•wholly insufficient for the conduction of heat ; besides, such an 
effect was disproved by direct experiment, as mentioned above 
(p. 23). 

Of the second point, we shall presently have to notice a com- 
plete investigation by Prof. Forbes. 

As to the third, with this construction, the heat absorbed by 
the mica was very trifling ; but by the more improved process 
since used by Prof. Forbes, (p. 27), we have seen this source of 
error is wholly got rid of. The employment of a pencil of 
parallel rays does not seem, upon consideration, materially to 
increase the intensity. 

The fourth point is no more than what had been already 
established by Prof. Forbes. 

With respect to the fifth head (including the most important 
part of these researches), it must be observed, that the differ- 
ences in the nature of the heat obtained by the intervention of 
diathermanous substances, are not the same as those between heat 
from luminous and dark sources. And further, in the experi- 
ments mentioned with radiations from different sources, no 
numerical results are stated. On this point we shall presently 
notice some more detailed researches of Prof. Forbes. 

The sixth point, on the subject of depolarization, is confess- 
edly one of the most delicate in the whole inquiry ; but for the 
same reasons as before, the effect of secondary radiation cannot 
be referred to as capable of having produced the differences 
observed. 

Unequal Polarizability of Heat from different sources : 
Forbes. 

Prof. Forbes's third series of Researches of Heat appears in 
vol. xiv. of the Edinburgh Transactions, having been read before 
the Royal Society of Edinburgh, April 16, 1838. It is also 



RETORT OX RADIAN'T HEAT. SI 

printed in the London and Edinburgh Journal of Science, 
vol. xiii. 

In the first section the author discusses the variable polariza- 
bility of the different kinds of heat. The establishment of this 
fact was his object in one portion of his second memoir. But 
these investigations having been objected to by some, and oppo- 
site results (as we have seen) obtained by Melloni, the author 
now repeated the inquiiy with every precaution. He rendered 
the rays parallel by a rock-salt lens, as Melloni had done, and 
operated at a sufficient distance from the pile : still the differ- 
ences in the rectangular positions, when different sorts of heat 
were employed, were as unequal as formerly. ' 

Having varied the experiments in every possible way, he still 
comes to the same conclusion as before, and gives the following 
results : — 

Source of Heat. Rays out of 100 Polarized. 

Argand lamp 78 

Locatelli do 75 to 77 

Incandescent platina 74 to 76 

with glass screen 80 to 82 

Alcohol flame 78 

Brass at 700° 66-6 

Do. with mica screen 80 

Mercury in crucible at 450° ... 48 

Boiling water 44 

Melloni' s opposite result of apparent uniform polarizability, 
the author then shows must necessarily arise from the use of 
mica piles, consisting of a number of distinct plates super- 
posed. Such a thickness of mica modifies heat from dark 
sources in such a way as to give the portion which it trans- 
mits the same character as to polarizability as luminous heat. 
Whereas Mr. Forbes's results were obtained by the use of mica 
split by heat (as before described), which includes so many sur- 
faces within a very small thickness, that the polarized heat ia 
comparatively unaltered in its character. He shows directly, 
that these piles transmit heat from a lamp sifted by glass, and 
from brass at 700°j in nearly equal proportions, while mica 
•016 inch thick transmits five times less of the latter than of 
the former. 

The second section relates to the dipolarization of heat. 
Pursuing the methods given in the first series, the author ascer- 
tained the proportion of heat dipoJarized by five different thick- 
nesses of mica. From the numerical results thus obtained, he 
deduces the value of the expression in Fresnel's formula, for 



32 REPORT — 1840. 

the retardation divided by the wave-length, either of which 
quantities being assumed, the other becomes known. 

In pursuing this calculation, the author finds, that if the 
numerator (or difl^erence of paths) be assumed to be the same 
as in light, the length of a wave of heat would result three 
times as great as that for red light. 

Upon this he is led into some important considerations bear- 
ing on the theory of undulations as applicable to heat. 

Almost exactly similar numerical results were obtained for 
the heat from an argand lamp, from incandescent platina, and 
from brass heated to 700°. 

At the Anniversary Meeting of the Royal Society of London, 
Nov. 30, 1838, the Rumford Medal was adjudged to Prof. Forbes, 
" for bis discoveries and investigations of the polarization and 
double refraction of heat." And in tlie report of the council 
announcing the award, a brief but appropriate testimony is 
given to the value of these researches. 

Intensity of Reflected Heat : Forbes. 

On March 18, 1839, Prof. Forbes communicated some re- 
marks to the Royal Society of Edinburgh on the Intensity of 
Reflected Light and Heat. 

The theoretical law for the intensity of reflected light, ori- 
ginally proposed by Fresnel, has been confirmed on quite difi"ar- 
ent grounds by the mathematical investigations of Mr. Green 
and Prof. Kelland. Yet scarcely any attempt has been made 
toward its verification by direct experiment, except in the cri- 
tical cases for polarized light originally assumed as the basis of 
the formula, and a few intermediate photometrical determina- 
tions by M. Arago. The uncertainty attending all photometry, 
led Prof. Forbes to conceive (about the end of 1837) that pei'- 
haps some confirmation might be obtained by ascertaining the 
law which prevails with respect to the intensities of heat in the 
corresponding cases ; an analogy which seemed extremely pro- 
bable from the facts already ascertained, relative to the change 
of polarization, &c., before noticed. 

In December, 1837, he made some first attempts, which were 
not altogether satisfactory. In the following winter he resumed 
the subject, and by a suitable apparatus for measuring the angles 
of incidence, he endeavoured to measure the intensity of heat 
reflected from surfaces of glass, steel and silver ; and though the 
results can hardly be yet considered completely accurate, yet in 
the case of glass the approximation to Fresnel's law is closer 
than any as yet exhibited hy photometrical observations : while 



HKPORT ON RADIANT HEAT. 33 

the observations accord much better with the law of Fresnel 
than with that deduced by Mr. Potter. In the instance of me- 
tals, Prof. Forbes considers Mr. Potter's discovery verified, that 
the reflexion is less intense at hig!;er angles of incidence : he has 
not yet been able to verify Prof. Maccullagh's itiference, that it 
has a n)inimura before reaching 90° ; and lastly, he observes that 
the quantity of heat reflected from metals is so much greater 
than Mr. Potter's estimate for light, as to lead him to suspect 
that all that gentleman's photometric ratios are too small ; this 
would nearly account for their deviations from Fresnel's law. 
He has also made some attempts for verifying that law by ob- 
servations on heat polarized in opposite planes. 

Mr. Potter, it is well known, mainly founds his objections to 
the undulatory theory on the discrepancy between Fresnel's law 
for the intensities of reflected light and his own photometrical 
determinations. He has therefore naturally been led into some 
controversial remarks on Prof. Forbes's results in a paper in the 
London and Edinburgh Journal of Science, to which Prof. 
Forbes has replied. 

Considering that the whole inquiry is as yet confessedly in 
an incomplete state, any further observations upon it in this 
place would be premature. 

Co7iclusion. 

In thus reviewing the different points of inquiry which liave 
been of late pursued relative to radiant heat, and the several 
important discoveries with which that research has been re- 
warded, I have for the most part preserved, under each head, the 
chronological order. 

The progress of dii^covery is here, I trust, too clearly marked 
to allow any real ground for these questions as to priority and 
originality, which have given rise to so much unhappy contro- 
versy between rival philosophers ; or to the less open, but 
equally lamentable manifestations of jealousy, in ambiguous ex- 
pressions of claims, into which men of science have been some- 
times betrayed. The dispassionate reviewer of the history of dis- 
covery at once best avoids all such controversial topics, and ful- 
fils the demands of critical justice, by a simple but careful 
statement of facts. 

In the present instance it appears to me that the share of cre- 
dit due to the distinguished parties respectively, who have co- 
operated to introduce the discoveries above reported, is suffi- 
ciently well-marked, and certainly ample enough in each in- 
stance to confer the highest celebrity on those who have borne 
the chief portion of the labour. 

VOL. IX. 1840. D 



34 REPORT — 1840. 

To the continental philosophers belongs the first invention of 
the instrument, without whose aid none of these investigations 
could have been accomplished ; while all tlie earliest and most im- 
portant discoveries of the varying diathermancy of substances ; 
the knowledge of the singular constitution of rock-salt, (which 
has placed a new instrument in the hands of the experi- 
menter) ; and the capital fact, disclosed by means of it, the re- 
fraction of heat from dark sources ; together with the very sin- 
gular phaenomena of the changes in the nature of heat, by trans- 
mission through certain substances ; the remarkable effect of 
smoked rock salt ; the circularly polarizing power of quartz for 
heat; — all these important discoveries (besides others of minor 
value) are imperishably associated witli the name of Melloni. 
Our own countiy as fairly andincontestably boasts, besides im- 
provements in the apparatus and methods, many important re- 
sults connected with the transmission of heat, accurate measures 
of its refraction, together with some indication of phtenomena 
analogous to those of diffraction. In addition to these, the 
sole and undisputed credit of first unequivocally establishing the 
grand facts of the polarization of heat, even from non-luminous 
sources, by transmission through mica, through tourmaline and 
by reflexion ; together with the peculiar and invaluable property 
of mica split by sudden heating (a fact holding a parallel rank 
with that of the diathermancy of rock salt) ; the dipolarization 
of heat; its consequent double refraction and interference; its 
circular and elliptic polarization ; its length of wave, and the 
production of that wave by transverse vibrations ; the confirma- 
tion of the circular polarization by the rock-salt rhomb, and 
the peculiar eftects of metallic reflexion ; these constitute the 
unquestionable claims of Prof. Forbes. 

On the main point in controversy between these two philoso- 
phers, the equal or unequal polarizability of heat from different 
sources, I have endeavoured to place the facts and arguments 
clearly before the reader ; but must confess my own conviction 
to be in favour of the unequal ratio of polarizability in the radi- 
ations from luminous and from obscure sources, while in some 
instances the apparently opposite results seem distinctly traced 
to known causes, and in others the equalization of the effects • 
appears to depend on some of those modifications which the in- 
tervention of screens produces in the nature of the rays of heat. 

The very remarkable class of phaenomena just referred to, is 
perhaps of all the recent discoveries that which seems most sin- 
gular and anomalous : that the same ray should acquire an entire 
change of property and nature by and in the act of simply pass- 
ing through certain media, seems little in accordance with any 



REPORT ON RADIANT HKAT. 35 

conception we can form of such radiation. Is this^ we may asU, a 
real change of constitution, or is it a separation or analysis of 
the ray into its components ? 

I have elsewhere remarked, that the terms " luminous" and 
" dark" heat are of somewhat barbarous appearance ; and the 
objection is more than etymological, especially as we now find 
the luminosity of the source is not the essential characteristic 
of the qualities of the rays. And again, in the compound radia- 
tion from Imiiinous sources, there is included a considerable poi'- 
tion of " dark" heat as disclosed by its relation to surfaces in 
absorption. 

The relations of heat to surfaces in absorption, and in the cor- 
responding inverse effects of radiation, are among the most im- 
portant portions of the subject ; and I have in consequence been 
desirous to draw particular attention to the very valuable inves- 
tigations of President Bache. 

The properties vvhich characterize the different species of heat 
(as we have seen) have been most remarkably developed, and 
principally studied, in the phaenomena of transmission. A wide 
field is open to the experimenter in connecting these properties 
with those belonging to the conditions of surface which produce 
the absorptive powers of bodies for different species of heat ; 
and these again with those which mark the differences in con- 
ductive power, and perhaps also capacity for heat. 

With regard to the establishment of a theory of the nature 
of radiant heat, we have seen that the hypothesis of undulations 
certainly supplies a clue to a vast range of phaenomena, especially 
those connected with polarization. 

The question of the identity of the heating and illuminating 
radiations seems clearly negatived by many experiments, if we 
mean it to apply in the sense of one physical agent. But if we 
refer to the possibility of accounting for the different effects by 
sets of undulations of the same aetherial medium differing in 
their wave-lengths, this probably presents fewer difficulties than 
any hypothesis of peculiar heat. 

We may perhaps suppose some other element besides the 
wave-length to enter into the explanation : or while we find that 
the heating effect is due to waves of greater length, it may also 
be true that the intensity or accumulation of waves, which is 
necessary for producing the sensation of light, follows a very 
different and much higher ratio than that requisite for producing 
heat ; and that this latter effect may be produced in the highest 
intensity by longer waves of the same aetherial medium, but not 
sufficiently accumulated to impress our visual organs. 

The difference in the polarizability of heat from different 
D 2 



36 REPORT— 1640. 

sources is not explained by the slight difference of refrangibility ; 
and Prof. Forbes is of opinion that we must in consequence 
look for its solution to a mechanical theory of heat in some re- 
spects at least different from that of light. It is even a ques- 
tion of some difficulty, why any portion of the heat should not 
be subject to the law of polarization which the rest obeys, unless 
we suppose the heating effect to be of so complex a nature, that 
some part of it only is properly due to rays analogous to those 
of light, while the other part of the effect is produced by a mode 
of action altogether different. 

To any such questions, however, we are hardly yet in a condi- 
tion to give a satisfactory answer ; but among the numerous 
points open to inquiry, I have dwelt more particularly on those 
which appear to me pre-eminently to require more extended in- 
vestigation before we can hope to obtain materials for construct- 
ing any substantial and unexceptionable theory. 



37 



Supplementary Report on Meteorology. By James D. Forbes, 
Esq., F.R.S. Sec. R.S. Ed., Professor of Natural Philo- 
sophy in the University of Edinburgh. 

[A Summary of the Contents will be found at the end of this Report.] 

1. The present Report on Meteorology is intended to be sup- 
plementary to a former one on the same subject, drawn up by 
me eight years ago, and printed in the Second Report of the 
British Association. 

2. It was in the contemplation of those persons who assisted 
in organizing the Association at York in 1831, that the reports 
on the progress of science should be GSiGni\al\Y progressive, — 
that the same authors, or others, should be engaged to continue 
from time to time their sketch of the ever-varying point of 
view which each science presents, not merely with the intention 
of registering something like a compendious history of facts, 
but likewise of philosophizing in some degree upon the new 
character which, during the elapsed period, science may have 
assumed, — of indicating the success, or not less instructive 
failures which may have occurred in attempts to carry forward 
our knowledge in the lines of direction indicated in previous 
reports, as the most hopeful or important, and of calling atten- 
tion to new fields of discovery, new instruments of research, or 
the collateral suggestions which may often be derived from the 
progress of the affiliated sciences. 

3. My aim in the following report will be— ^^r^^, to sketch 
the broad features of the science as it stands ; secondly, to give 
the bibliography of the subject within a definite period of years ; 
and thirdly, to point out the more conspicuous deficiencies of 
our knowledge, and the kind of observation, experiment or rea- 
soning by which these blanks may be supplied. In fulfilling 
this last and responsible duty, the reporter does not lay himself 
open to the charge which has sometimes been very needlessly 
preferred, that he is only attempting to stimidate where there 
is more than energy enough, — that the tide of science is in such 
full flow, that any external or partial impulse does no more 
than propagate a local disturbance ; that the grand prime- 
movers, — the wants, ambition, and restless curiosity of men, — • 
would act just as strongly, without assistance or direction, in 



38 REPORT — 1840. 

urging the mighty mass steadily forward in its regulated 
course ; and that at the same height precisely, and at its ap- 
pointed hour, will its proud waves be stayed. Let us remem- 
ber that, even admitting the sufficiency of labourers and of 
enterprize, it is necessary that this power should receive a use- 
ful direction, that it may not be wasted by misapplication, en- 
feebled by diffusion, and degraded to unworthy ends. He who 
points out distinctly where energy may be usefully applied, 
— who concentrates scattered and disunited forces, — who holds 
up continually to view the demands of science as worthy of in- 
dividual pursuit and national encouragement, in opposition to 
the popular call for the bare quantum of information gleaned 
from desultory experience, which may penuriously supply the 
exigency of the moment, — he it is who contributes to the ulti- 
mate economy of mental labour, to the advancement of sub- 
stantial knowledge, and, it may be, to i*aise the intellectual cha- 
racter of his country. 

4. Impressed with these views of the possible utility of re- 
ports, such as those which the British Association has from 
time to time required of its members, I attempt the task of 
continuing my report with more reluctance than I felt in com- 
mencing it; and, lest more may be expected than I am at all 
prepared to fulfil, I will premise, that I shall feel myself at 
liberty to select, for fuller illustrations, those departments of 
the widely ramified science of meteorology on which T may 
have some matured suggestions to offer, without in the least 
degree inferring a depreciation of those topics which the limits, 
both of time and space, to which I am confined, prevent me 
from dwelling upon in equal detail. 

5. It is not proposed, then, in this report, to supply nearly 
all the deficiencies which, I am very sensible, exist in the pre- 
vious one, nor yet to enter at length upon subjects which in it 
were comparatively untouched, but rather to select such topics 
as bear most upon general principles, and afford room for prac- 
tical suggestions ; giving, as far as may be, a bibliography of 
meteorological science in its wider acceptation, particularly 
during the last eight years. 

6. And here I would acknowledge the useful suggestions 
and information which I have received from the excellent Ger- 
man edition of my former report, translated and most materi- 
ally amplified by Mahlmann*, in which many involuntary omis- 
sions have been ably supplied, and subjects purposely passed 

* Abriss einer GescMchte der neuern Fortschi-itte unci i/es gegenwiirtigen 
Ziistandes der Meteorologle, &c. iibersetzt und erganzt von W. Mahlmann. 
Berlin, Liuleritz, 1836, pp. 248. 



SUPPLEMENTARY REPORT ON METEOROLOGY. 39 

over with little notice, copiously illustrated. To this work 
(which is to such a degree original, that I may be allowed to 
recommend it,) I shall frequently be indebted in the course of 
these pages. 

7. The useful Repertorium (or Analytical Index to Scientific 
Literature) of Fechner,has been succeeded by the ably-conducted 
work of Dove and Moser, under the same title, in which it is 
proposed, somewhat after the manner of the British Association 
Reports, to analyse the various publications connected with 
physical science, so as to present, in a cycle of five or six 
years, a digest of all that has appeared on each subject in the 
preceding period. The third volume of Dove's Repertoriimv'^, 
which has lately appeared, contains a valuable analysis of works 
on one portion of meteorology. 

8. To Professor Kanitz of Halle, beyond all comparison the 
most devoted meteorologist of the present day, we are indebted 
for the most laborious systematic compilation which has yet ap- 
peared upon the subjectf ; a compilation, however, which in- 
cludes many important contributions and generalizations of his 
own, and which is as much distinguished by copious references 
to the works of all who have preceded him, as many works of 
the English and French schools are by the total omission of 
such literary justice. In the first volume we have the subject 
of Temperature generally discussed, and that of Wind and of 
Rain. In the second, is the most complete collection of facts 
anywhere to be found, on the laws of diurnal and annual 
changes of temperature, on isothermal lines, and the proper 
temperature of the globe, followed by a chapter on barometric 
oscillations, and another on atmospheric electricity. The third 
volume is chiefly devoted to optical meteorology and terrestrial 
magnetism. This is the only work we have which can pro- 
perly be considered as a system of meteorology (with the ex- 
ception, perhaps, of the article Meteorology in the Encyclopaedia 
Metropolitana, mentioned in the former report). 

9. The attempt to systematize and direct meteorological ob- 
servations within the last eight years, is in nothing better shown 
than in the various " Instructions for Observers," which have 
appeared during that time from various and very influential 
sources. Some of the special contents of these instruments we 
shall have occasion to notice, as well as the spirit which they 
are likely to impress upon future systems of observation, and 

* Berlin, Veit & Co., 1839, 8vo. 

\ Lehrhuch der Meteorologie, Svo. 3 Bande, 1831 — 1836. The same au- 
thor has more lately published Experimental Physics, and Lectures on Meteor- 
ology. 



40 REPORT — 1840. 

on national undertakings ; in the mean time we may enumerate 
the principal ones by tlieir titles. 

I. Instructions pour faire des Observations Meteorologiques 
et Magn^tiques, par A. T. Kupffer. St. Petersbourg, 1836, 
8vo, pp. 77' Chiefly instrumental details ; including, however, 
a theory of the wet bulb hygrometer. 

II. Instructions for making and registering Meteorological 
Observations in Southern Africa. Drawn up under the direc- 
tion of Sir John Herschel*. 

III. Instructions pour le Voyage de la Bonite ; Physique 
du Globe, par M. Arago, Comptes Rendus de I'Academie des 
Sciences de Paris, I. 380. Annuaire du Bureau des Longi- 
tudes, 1836. 

IV. Instructions pour I'Expedition d'Algerie, 1838. Par le 
meme, Comptes Rendus, VII. 206. 

V. Report of the Committee of Physics and Meteorology 
of the Royal Society, on the Objects of Scientific Inquiry in 
those Sciences ; drawn up for the Antarctic Expedition of 1839. 
Instructions for making Meteorological Observations, pp. 53 — 
79 ; with an appendix of Tables. 

10. But of all periodical literature, the work which gives the 
fairest representation of the progress of physical science north 
of the Alps, is Poggendorff's Annalen der P/ii/sik, which, even 
as a bibliographical compendium, is invaluable. In the nu- 
merous volumes of this admirably edited work, are to be found 
the best papers published on meteorology, and all the kindred 
sciences, whether in Germany, France, or Britain. The edi- 
torial skill and impartiality with which this work is conducted, 
render it most deserving of support in every country ; whilst 
the high scientific standard, according to which articles are ad- 
mitted or selected, is highly creditable to Germany ; where 
alone, perhaps, in Europe, so learned a work would find ade- 
quate supportf . 

11. I regret very much that, from the difficulty of procuring 

• These instructions, printed by the South African Institution, have, I be- 
lieve, been republished in the Journal of the Royal Geographical Society. See 
also Instructions for Observation, and Suggestions for iVIeteorological Inquiry, 
in the first volume of the Transactions of the Meteorological Society of Lon- 
don, 8vo. 

f M. Poggendorff, not satisfied with translating the best foreign memoirs of 
the day (to facilitate which he has recently added an annual supplementary 
part), has, on various occasions, published, for the first time in German, older 
memoirs, of considerable length and difficult}', for the purpose of presenting his 
readers with a complete view of the progress of any science, without searching 
further than his own pages. Thus, he has lately translated Fresnel's Memoir 
on Diffraction, and Sir James Hall's papers on the Consolidation of Strata. 



SUPPLEMENTARY REPORT ON METEOROLOGY. 41 

with the least regularity the periodical literature of Italy, I am 
unable to present any connected view of what has lately been 
effected in that country for lueteorological science. The obser- 
vations of Sig. Cacciatore, of Palermo, on a uniform system of 
standards for meteorological observations*, are among the few 
that have come to my knowledge. Let us hope that the re- 
cently founded Association of Italian Philosophers Avill do 
something towards supplying the want of information under 
which we labour of the actual progress of science in that 
country f. 

12. Since the last Report on Meteorology, Mr. Luke Howard 
has published a second greatly enlarged edition of his Climate 
of London!, which deserves to be considered, not as a mere 
journal of observations, but in some degree as a systematic 
veork. Professor Stevelly, of Belfast, promises an elementary 
treatise, the first in our language. M. Quetelet, of Brussels, 
has published a full account of the history of Meteorology in 
the Pays Bas§, to which, hoM'ever, his own contributions are 
by far the most important. 

13. This might appear the natural place for eniunerating 
the public establishments lately founded for cultivating 
(amongst ^ther things) the practical part of meteorology. 
When, however, we shall have considered a little minutely the 
condition of the science in its several branches, we shall be bet- 
ter able to appreciate their value, and suggest measures for 
their extension, (See Suggestions at the close of this Report.) 

14. I proceed now to the different departments of meteor- 
ology, nearly in the order in which they were discussed in my 
former report||. I have already stated (4.) why I shall hold 
myself at liberty to enlarge more upon some topics than others, 
or even restrict myself occadonally to a mere enumeration of 

• De reditjendis Ohservationihus Meteorologicis. Panormi, 1832. 

t In the JBibliotheque Vniverselle de Geneve, is generally to be found a fuller 
notice of Italian papers than in other journals published north of the Alps. 
This practice might, with advantage, be yet further extended. 

Since this was written, I made it my particular business, during a visit to 
London, to search for Italian Scientific Journals. In none of the public libra- 
ries where I made application, as most likely to obtain such works, could I 
find that Italian Journals are regularly subscribed for or received ! A. new 
Tuscan Scientific Journal is recently announced, with the names of Amici and 
Savi amongst the editors. 

I 3 vols. 8vo, Lond. 1833. 

§ Aper^u Historique des Observations de Meteorologie, faites en Belgiqne 
jusqu'd cejour, 4to, Bruxelles, 1834. 

II I take this opportunity of returning my thanks generally for the commu- 
nication of valuable meteorological papers, in a detached form, from the respect- 
ive authors, which, for the most part, will be found cited in the following pages. 



42 REPORT — 1840. 

memoirs, which may assist the researches of others, and en- 
able them to draw their own conclusions. 

I. — Temperature. 

15. Meteorology may, in some sense, be considered as a 
mere branch of the science of heat in its widest application. 
Were our globe and atmosphere in a uniform state with re- 
gard to heat, and not subjected, by astronomical and cosmical 
laws, to perpetual and material changes in the distribution of 
temperature in its solid, fluid, and gaseous parts, the simplest 
considerations would suffice for the solulioia of the few pro- 
blems which could then be called meteorological. 

16. It is to the different inclination of the solar rays, that 
we trace the effect of climate varying with latitude, and of cli- 
mate varying with season. It is to the unequal absorption and 
radiation of heat by seas and continents, that we ascribe the 
curious inflections of the isothermal lines, and the characters 
of moderate and excessive climates. It is to the combination 
of these causes with the rotation of the globe, that we attribute 
all the phainomena of wind, from the steady monotony of the 
Trades, to the capricious changes of higher latitudes, the Tor- 
nados of America, and the Typhoon of the Chinese seas. It is 
to the mechanical transport of great masses of air due to 
change of temperature and consequent expansion, that we look 
for the explanation of most of the irregular, and several of the 
periodical barometi'ic fluctuations. Lastly, it is to the varying 
conditions of temperature proper to the day and night, to one sea- 
son and another, in high latitudes and low, that we look for prin- 
ciples to guide us in the difficult, but important determination of 
the hygrometric elements of our atmosphere, the ceaseless mo- 
difications of that fluctuating ocean of vapour which floats in- 
dependent of, and unobstructed by, the permanently elastic 
envelope of our globe, which (though comparatively unheeded 
by us) is subject to all the variations of pressure and tempera- 
ture of the common atmosphere, but through limits far wider, 
and to changes of physical condition, which the other, from its 
permanent character, never presents. 

17. If we choose, then, to consider the grand meteorological 
problem for a moment synthetically, instead of analytically — 
T mean, by regarding the known causes which influence cli- 
mate, and applying to these the laws of distribution and com- 
munication of heat, which are deduced from laboratory experi- 
ments, and from the first data or experimental axioms of that 
science, — we have, at least, the advantage of perceiving the 
magnitude, interest, and definitivencss of the problems with 



SUPPLEMENTARY REPORT ON METEOROLOGY. 43 

which meteorology, in the philosophical sense of the term, is 
conversant. Those who limit themselves to a few daily mecha- 
nical observations of the barometer and thermometer, or who 
even apply the results of these simple, but (if well conducted) 
important observations, are little aware that the science they 
cultivate is capable of giving definite answers to questions 
which might seem further removed from human apprehension 
than even the problems of physical astronomy, such as the con- 
dition of the interior of our globe witli respect to temperature,— 
and in some degree its history as regards periods of geological 
convulsion, — the whole measure of solar heat received by our 
globe in a given time, — the condition of the highest, and for ever 
inaccessible parts of our atmosphere, — the temperature which 
reigns in the vast regions of space, remote from the influence of 
any planet or satellite, however small, whose presence and pro- 
per heat would 5'et influence such an experiment ; — these are 
amongst the great cosmical problems which we do not mean to 
say have been solved, but which there is little reason to doubt 
that we are in the fair way of one day being able to solve by 
instruments such as we now possess, with the aid of theoretical 
investigations identical in kind with many which have been 
completely mastered. 

18. Of Instruments, those which are most called for are such 
as acquaint us with certain physical constants, or approximate 
constants, which determine for our globe and its atmosphere 
the particular application of the general laws of the Conduc- 
tion and Radiation of Heat. Of theoretical Investigations, 
wo require such as shall solve with sufficient generality the 
problems with which we have to deal, but stripped of those 
exuberant claims to mathematical precision which cramp their 
application and discourage those who know how far we are 
from even the chance of ever attaining to a degree of accu- 
racy which such niceties pre- suppose. The theoretical in- 
vestigations of most use, then, are those which, taking the pro- 
blem in a general way, show exactly upon what arbitrary con- 
stants the determination (for instance) of the climateric condition 
of any point of the globe at any moment depends. This is a 
task of no small difficulty, even in the simplest form in which it 
can be put. 

19. It infers a knowledge (1) of the fundamental laws or 
axioms of the science of heat (such as the law of expansion, 
variation of specific heat with densitj^, conduction, radiation). 
(2) Of all the physical circumstances which can possibly influence 
the temperature of our globe, that is, the communication of heat 
to, or abstraction from it (I mean their existence, not their de- 



44 REPORT — 1840. 

termination), such as solar radiation, the pi'oper heat of the earth, 
the proper heat of the atmosphere, the proper heat of space. 
(3) Supposing these preliminaries rightly assigned, next comes 
the arduous mathematical investigation of the way in which the 
unknown constants which represent these various energetic 
sources of modification, enter into the final expression of atmo- 
spheric temperature, or whatever be the particular problem under 
consideration. (4) For the determination of the constants 
(which are supposed to be reduced to the least number of inde- 
pendent elements), the analyst is further bound to mould his 
formulae into such a shape as to insulate a certain number of the 
constants in such a way that they may be determined by direct 
physical experiment ; whence the others not so determinable 
may be inferred by the principle of exclusion, which assigns the 
difterence between the sum of effects due to causes already esti- 
mated, and the observed effect, to a remaining cause (such as 
the temperature of space) M'hich does not admit of such direct 
estimation. 

20. The duty of the experimentalist is thus clearly defined. 
Perhaps the most important observations which man can make 
for furthering the theory of the universe, are such as no general 
sagacity, no patient attention to mere facts as they are presented m 
in the course of nature, could possibly have indicated. And it 1 
is the most satisfactory and encouraging proof that such a syn- 
thetic mode of treating the problem is not an injurious or an 
illusory one, when we find many concurrent observations set on 
foot in the way which theory has indicated, leading under vary- 
ing circumstances to a common result. Such instances are not 
uncommon, and will fall to be noticed hereafter*. 

21. It is plain, then, that there ai*e three departments of sci- 
ence which must go hand in hand to perfect a mixed science 
like that of meteorology. Fh'st, the experimental philoso- 
pher must advise generally on the experimental axioms, and on 
the modifications which they are to receive in order to allow for 
causes which yet do not admit of nice numerical estimation ; 
he must further be fully persuaded that no energetic cause of 
modification has been left out of account ; for in so delicate an 
inquiry, where the principle of exclusion is to be acted upon, 
enormous errors would result from any oversight in this stage 

* Such, for instance, as tlie geometrical diminution of the range of animal 
temperature beneath the sui-face of the ground, as we descend in arithmetical 
pro£;ression : the uniform retardation of epoch in the same circumstances, and 
perhaps we might have added a few years ago, the agreement of several different 
methods of approximation to the actual temperature of space. See former Re- 
port, p. 203, and Mahlmann's Translation, p. 14. 



SUPPLEMENTARY REPORT ON METEOROLOGY. 45 

of the process. Secondly, the mathematician requires the ut- 
most resources of his analysis to ohtain in a definite and tangi- 
ble form the resultant action (we will suppose that tempera- 
ture is the question) of all the heating and cooling influences 
upon a certain point, whose coordinates are given (including 
elevation in the atmosphere, or depression below the surface), 
and at a particular instant of time. And in this investigation 
he will, as we have said, chieflj' show his skill in the precision 
which he gives to his results, the judgement with which he intro- 
duces needful approximations at that stage of the investigation 
which shall tend most to simplicitj^, and in the exhibition of his 
results in forms adapted to experimental verification. Then 
follows the duty, in the third place, of the observer, or practical 
meteorologist, which is to follow the indications which theory 
assigns for the determination of data, and for which the me- 
thods will be indicated by a competent knowledge of experi- 
mental philosophy, and even by prolonged tentative researches in 
the laboratory. It is not unoften the provoking result of the 
labour expended by the two first sections of investigators, that 
the whole problem is found to turn upon certain quantities, 
whose nature is perfectly well understood, but vi^hich are, 
and threaten for ever to remain perfectly unknown. I need 
hardly stop to point out that such a threefold division of labour 
is to be found in many other sciences, and notably at present in 
that of magnetism. A right appreciation of the steps leading 
to the solution of such complex mixed problems, which in fact 
involve a whole science, is the first step to their solution 5 and 
we commonly find that this is performed by the appearance of 
some master mind, capable of seizing the question in all its ex- 
tent and under every one of these forms — depending on a ver- 
satility of mental endowment of no common order. This is 
what Newton did for the science of gravitation, what is now 
being done by the union of many for the science of optics, and 
what Gauss has pre-eminently done for the science of mag- 
netism. 

22. It will conduce to clearness if it is understood, that so far 
as possible, in what follows, we shall keep in view these different 
aspects of meteorological science ; and combining, as on a for- 
mer occasion, the bibliography with the general detail, I shall 
proceed to the different parts of the science of Temperature 
somewhat in the order adopted in the last report. 



46 REPORT — 1840. 

A. Thermometers^'^' . 

23. Fixed Points. — Legrandf has studied once more the 
vexed subject of the rise of the thevmometric zero point. He 
finds that the pressure of air has no influence, thus confirming 
the observations of Bellani ; the molecular change in the form of 
the bulb is therefore the remaining cause, and this is confirmed 
by finding that it depends on the nature of the glass ; not oc- 
curring (according to the author) in Crystal. Now if by Crystal 
is meant, as I believe to be the case, Flint Glass, this obser- 
vation is at variance Avith that of other observers, flint glass 
being generally used for thermometers in this country. Since 
writing the last report, I have myself found the following dis- 
placement of zero in thermometers all warranted standards by 
the following makers — Trough ton andSimms(tvvo), Adie, Crich- 
ton, Collardeau : — 

+ 0°-56, + 0°-33, + 0°-41, -F- 0°-54, + 0°-35, Fahrenheit. 

24. Correction of Scale. When the points are fixed and 
the thermometer graduated, the degrees may be examined by 
the method of BesselJ. Rudberg has proposed another founded 
on similar principles§, and I have given an account of a method 
employed by myself, and attended, I think, with considerable 
practical advantages, in the introduction to a paper on the Tem- 
perature of Hot Springs II . 

25. Every one must have noticed the difficulty of reading ther- 
mometers quickly and correctly when the tube projects much 
in front of the scale, owing to an evident error of parallax, which 
it requires some experience to avoid. A particularly ingenious 
method of correcting it has been communicated to me by M. 
Valz, the eminent astronomer of Marseilles, which though un- 
published, I trust he will forgive me for mentioning. By plun- 
ging two- thirds of the diameter of the tube into the material of 
the scale so that the plane on which graduation is made is ad- 
vanced in front of the mercurial column to the amount of one- 
third of the radius of the tube, it may be shown that the error 
of refraction will exactly correct the error of parallax. 

26. For self-registering thermometers for maximum tempe- 
ratures, such as are now in demand for experiments on deep Arte- 
sian Wells, we have the overflowing principle of Cavendish and 

* See last Report, p. 208. Mahlmann, p. 25. 
t Comptes Rcndus (Paris), iv. 173. 

X Berzeliua, Jahreshericht, xv. 70, quoted in Poggendorff's Annalen, xxxvii. 
376. 

§ See a full illustration of Bessel's metliod in Kupffev's " Instructions," p. 5. 
II Philosophical Transactions, 1836, p. 571. 



SUPPLEMENTARY RKPORT ON METEOROLOGY, 47 

Magnus* revived by Walferdin, and his instruments are usually 
employed in Parisf. The overflovving principle has been used 
(in the same way as in Wollaston's thermo-metrical barometer) 
for constructing a thermometer sensible to small change of ani- 
mal heat by Dr. Marshall HallJ. Jurgenson, the chronometer- 
maker of Copenhagen, has proposed a clock for estimating the 
mean temperature of limited periods, in which the compensation 
shall be inverted, and the natural effect of temperature on the 
rate of an uncompensated clock exaggerated§. 

27. Several other methods or new applications of known 
principles have been proposed for the measure of temperature 
besides that of expansion commonly emplojred. The extensive 
introduction of the thermo-electric pile of Nobiliand Melloni, in 
delicate researches on radiant heat, has suggested the use of the 
same principle in other cases. Indeed it seems peculiai'ly 
adapted for ascertaining the condition of inaccessible points in 
respect of temperature. M. Peltier, of Paris, I believe, first pro- 
posed the application of long wires of heterogeneous metals to 
ascertain at a distance the temperature of their point of junction, 
however distant. The method is briefly this : suppose two 
wires of copper and iron respectively, and of equal lengths, laid 
side by side and soldered at each end. Let one of the wires be 
cut, and a galvanometer introduced into the open circuit thus 
made. It is well known that the galvanometer needle will not 
stand at zero under these circumstances, unless both solderings 
have a common temperature. As the temperature of one ex- 
ceeds or falls belovv that of the other, the index will move in one 
or other direction, and in a well-constructed instrument the de- 
viations will be almost exactly as the variations of temperature {|. 
Thus, one junction of the wires being plunged in water of known 
temperature, and the positive or negative deviation of the galva- 
nometer being known and converted into thermometric degrees, 
the temperature of the other soldering (which may be inaccess- 
ible and removed to a considerable distance) becomes known. 
This very ingenious arrangement was shown to me in June, 
1835, by M. Peltier, whose acquaintance I owe to the attention 
of M. Elie de Beaumont. 

28. The application of the thermo-electro-magnetic princi- 
ple becomes easy in very many cases. It has been proposed for 
pyrometers by M. Pouillet, who has compared the march of such 

• First Report, p. 209. f Compies Rendus (Paris), ii. 505, 619. 

X British Association Reports. 

§ Comj^tes Rendus, iW. \^2. Compare First Report, p. 213. 
II I am aware that this position has been controverted, I am satisfied, how- 
ever, of its general truth from careful experiments. 



48 RKPORT— 1840. 

an instrument at high temperatures with that of an air pyrome- 
ter*, and at very low temperatures obtained by means of M. 
Thilorier's happy discovery of the solidification of carbonic acid 
with air and alcoholf. 

29. MM. Becquerel and Breschet have employed the same 
method for the determination of the temperature of water at 
great depths by sinking the experimental junction of the wires. 
As may be supposed, however, in such cases, great attention is 
requisite to prevent the slightest chemical action, which would 
develope its proper current. They made their observations on 
the Lake of Geneva|. 

30. The same ingenious experimenters have applied this me- 
thod of measuring temperature to the living animal fibre, by 
thrusting a compound needle into the muscular tissue, and with 
very curious results §. M. Dutrochet has lately applied the 
same method to ascertain the proper temperature of plants, a 
yet far more difficult inquiry ||. His experiments have been 
fully corroborated by MM. Van Beek and Bergsma^, 

31. I have applied M. Peltier's apparatus for the very obvious 
purpose of checking the zero point of thermometers sunk in the 
ground to such a depth that their scale can never be re-examined. 
For this purpose, along with a thermometer 24 French feet 
long**, I sunk a thermo-electric pair of iron and copper, com- 
pletely defended in all its length with a casing impervious to 
water, and its indications have been generally satisfactory. I 
had hoped that, by the use of wires of sufficient thickness, the 
thermo-electric current might be communicated from great 
depths. From experiments which I have made, I am inclined 
to think that their use must be very much limited in this respect, 
on account of the rapidity with which the energy of the circuit 

* Cotnptes Rendus (Paris), iii. 782. 

f Ibid, i. 513. Professor Muiicke, of Heidelberg, has investigated with 
great care the law of dilatation of alcohol, and the result gives for ordinary 
atmospkeric temperalures, a value very sensibly different from the mean dilata- 
tion commonly received from Dalton's experiments. He has also given the 
result of several series of observations on other fluids, and given formulae of ex- 
pansion for each. — Petersburg Transactions — Paper read oth Sept. 1834. M. 
Rudberg has re-examined the expansibility of dry air and gases (Poggendorfl's 
Annalen), and he finds an expansion of only -364 or '365 between freezing and 
boiling water instead of •375, as was given ver)' nearly both by ]")alton and Gay 
Lussac. The scientific world will, no doubt, hesitate a little to adopt the new 
determination of this important element, even with all possible respect for M. 
Rudberg's known skill as an experimentalist. 

X Bibliotheque Universelle, Nuuiel/e Serie,vii. 173 (1837). 

§ Comptes Rendus (Paris), i. 28, iii. 771. 

II Ibid, viii. C95, 741, 907. ix. G13. Temp, of Insects, ix. 81. 

•[[ Ibid, ix. 328, ' ** See below. Art. (9G.) 



SUPPLEMENTARY REPORT ON METEOROLOGY. 49 

diminishes with the length of the conducting wire. Some ad- 
vantage is undoubtedly gained by using two or three pairs, 
acting simultaneously, instead of one. Wherever distant com- 
parisons are intended, it is of great consequence to have a 
standard thermo-electric combination, by which any change in 
the sensibility of the galvanometer may be tested. 

32. A method of determining the temperature and pressure 
of the atmosphere depending on very different principles, has 
lately been proposed by M. Arago*. It depends on the known 
optical principle, that if a pencil of light radiating from a small 
and distant source be divided into two parts, and one of these 
be in the least degree retarded more than the other, coloured 
fringes will appear when the two pencils are re-united and suf- 
fered to fall upon a screen or received on an eye-piece. If by any 
arrangement, whether of reflexion or refraction, these bands 
have been already formed, their breadth and aspect will be 
changed by such a retardation of either component pencil. 
Now air rai-efied, whether by heat, diminished pressure, ox the 
intermixture of vapour, acts less energetically in retarding light ; 
consequently a tube with glass ends, filled with such modified 
air made to transmit one pencil, whilst the other passes through 
a precisely similar tube of standard air, will exhibit by the pro- 
duction of movement of the fringes very minute changes in its 
physical condition. It remains to be shown, however, by what 
mechanical adaptations M. Arago proposes to make this delicate 
experiment susceptible of general application. This he pro- 
poses to point out in a future memoir f. 

33. The comparison of ordinary thermometers with standards 
is often a matter of great importance, and too little attended to. 
The increasing demands of science require a proportionable in- 
crease in the consistency of instrumental indications ; not so 
much indeed for ascertaining the temperature, as in many other 
experiments connected with the temperature of the ground, 
rivers and hot springs. Travellers should seize every oppor- 
tunity to verify the freezing points of their instruments, and this 
is an easy matter ; but to compare thermometers at temperatures 
above 100° F., is a practical problem of far greater difficulty than 
is commonly imagined. Plunging them together in laboratory 
vessels of hot water is a most unsatisfactory process, even if the 
sensibilities of the instruments be pretty equal. If they are 
very unlike, it is all but impossible, although the correction for 
the gradual cooling of the medium becomes then a pretty mathe- 
matical problem %. Where the investigation is an important one, 

* Comptes Rendus (1840). f Ibid. 

X Fourier, Theorie de la Clialeur, p. 357, and Kelland's Theory of Heat, p. 84, 
1840. E 



50 REPORT — 1840. 

or many instruments are to be compared, constant sources of 
heat, natural or artificial, cannot be too carefully sought. Bark 
pits, natural hot springs, even the waste hot-water of steam- 
engines, and the boiling point of some liquids, such as alcohol, 
may be usefully employed*. 

B. Atmospheric Temperature^. 

34. Under this head we consider the temperature of a given 
spot at different times. These variations are diurnal, annual, 
and those of long period. 

35. A summary of valuable facts on this subject may be found 
in 'K:&miz's MeteorologieX and Dove's Repertoriu)n§. We can 
only point out a few general facts of especial importance. 

36. The general practice in Germany of expressing periodic 
changes of temperature by series of the form 

T = A + B sin (^ + C) + D sin {2 x + E) + &c., 

where x is the hour angle, or the fraction of a year, is attended 
with considerable advantages, especially for the purposes of in- 
terpolation ; and if this has sometimes been carried perhaps too 
far, yet the reductions are on the whole very superior to those 
in use in this country. 

37. The value of hourly observations of temperature seems 
now to be fully admitted, and the two-hourly meteorological 
observations connected with the recent magnetic expeditions 
fitted out by the English government, are likely to be of the 
highest importance for science. In the mean time we may quote 
the following important contributions, in addition to those spe- 
cified in the former report. 1, Goldingham's hourly observa- 
tions, three times a month at Madras ||. 2. Brandes's observa- 
tions at Salzuflen (lat. 52° 3' N.), made every hour in the year 
1828^. 3. The observations which, at the earnest suggestion 
of the Meteorological Committee of the British Association at 
its first meeting at York, have been so ably and zealously car- 
ried on hourly for seven complete years, under the direction of 
Mr. Snow Harris at Plymouth. The means have been regularly 

• I have found by the most careful experiments that the temperature of the 
vapour of impure alcohol remains surprisingly steady, which was before re- 
marked by Hugi {Alpenreise, Solothurn, 1830), but it is not the same with 
aetlier. There are some interesting experiments on the constancy of the tem- 
perature of vapour from saline solutions in the late volumes of PoggendorfF's 
Annalen, especially by Rudberg, xxxiv. 527. 

t See former Report, p. 210. Mahlmann, p. 31. % Vol. iii. p. 342. 

^ Vol. ii. p. 1. II Madras Observatory Papers, calculated by Dove. 

% Archiv der Pharmacie, Reihe ii. Bd. xi. 1, quoted in Poggendorff, xli. 635, 
and PoggendorfF's Remarks, xli. 630. Compare Comptes Rendus (Paris), i. 204, 
and Dove's Repertorium, iii, 345. 



SUPPL.KMENTARY REPORT ON METEOROLOGY. 51 

calculated and communicated to the Association in two reports 
on the subject*. 4. A most interesting series of observations 
made every two hours in the inhospitable regions of Nova Zem- 
bla, has been published by M. von Baer of St. Petersburgh, to 
whom I am indebted for a copy of his papers f. Some of his 
results we will immediately mention. 5. Dr. Richardson has 
undertaken the most laborious but most useful task of reducing 
into order, and into their mean results, the extensive series 
of two- hourly observations made in various years in the arctic 
regions of America by the expeditions of Parry and Franklin;}:. 
This has also been partially done by M. von Baer, in the me- 
moirs last-cited, so that we have in some measure a more com- 
plete meteorological knowledge of the climate of these desolate 
regions than we can be said to possess of that of our own coun- 
try. Dr. Richardson has carefully compared his diurnal curves 
with those of Leith and Plymouth, and we find the constancy 
of the interval between the hours of mean temperature § here 
remarkably reproduced, and also in a remarkable manner, Brew- 
ster's law of the correspondence of the mean temperature of two 
hours of the same name for the whole year with the mean tem- 
perature of the year||. The latter fact comes out exceedingly 
well also from the tropical observations of M. Freycinet^, and 
from the table of Brandes already referred to**. 

38. All these observations go a long way towards the il- 
lustration of those general laws of climate which may be con- 
sidered in some measure independent of local causes. It is not 
easy perhaps to conceive a more violent contrast of climate than 
the continental one of arctic America, and the insular one of 
Plymouth. It were undoubtedly to be desired, however, that 
these observations were extended to tropical regions ; and the 
expeditions recently fitted out to St. Helena, the Cape of Good 

* British Association, Fifth Report, p. 181 ; Eighth Report, p. 26. 

t Ueber das CUma von Nowaja-Semlja und die Mittlere Temperatur insbe- 
sondere; Ueber den Jdhrlichen Gang der Temperatur in Nowaja-Semlja. Von 
K. E. V. Ba.er.-^Bulletin de I'Acad. Imp. de St. Peter sbourg, t. ii. No. 19, 

X Journal of the Royal Geographical Society, 1839. 

§ See First Report, p. 211. 

II Richardson, p. 39. From a communication made by Mr. Harris at Bir- 
mingham in 1839, it appears that hourly observations have been made at Phi- 
ladelphia (United States) and in Ceylon ; but the results are not published. 

\ Poisson, TMorie de la Chaleur, p. 465. 

** To these may now be added two sets of hourly observations in Inverness- 
shire, made at the expense of the British Association under the direction of 
Sir D. Brewster. From the comnnmication made by that gentleman to the 
Meeting of the Association in 1840, since this report was written, it appears, 
that in these observations also, the constancy of the interval between the hours 
of mean temperature mentioned in the text, is well preserved. 

K 2 



52 REPORT 1840. 

Hope, and the possessions of the East India Company, will 
doubtless ere long afford this information*. 

39. The interesting tables of Von Baer and Richardson illus- 
trate most remarkably the different progress of solar heat in 
arctic and temperate latitudes. The maximum daily range 
which occurs in the end of July at Padua, and exceeds 9° cent., 
occurs in March in Boothia (North America), and at Felsen Bay 
(Nova Zenibla), in April f, the values being about 7° cent. At 
Leith the range is nearly uniform from April to July, and does 
not reach 6° cent., a proof of a temperate or insular climate. 
When the sun is always below the horizon, the diurnal curve is, as 
may be supposed, very uncertain, and wavering. In winter in 
Nova Zembla there is a sensible increase of temperature towards 
midnight, at both stations | ; and something of the same kind is 
visible in several of Dr. Richardson's winter curves. 

40. The dependence of the form of the annual curve upon 
the insular or continental character of a locality, does not need 
here to be insisted on. But it is interesting to observe the 
contrast between the climates of arctic Asia and arctic Ame- 
rica, both so rigorous, yet so unlike : — 

The mean temp, of Nova Zembla is ie«F. Of Fort Franklin 17-6 

Mean temp, three summer months .'36-5 „ 50-4 

,, three winter months — 3 ,, — 17'8 

Nova Zembla, therefore, is a climate of wi-etched mediocrity ; 
one of the most dreary in the known world ; the summer tem- 
perature scarcely rises above the freezing point ! whilst arctic 
America enjoys a European warmth for at least some weeks. 
The warmest month at Nova Zembla (August) has a temperature 
(39° F.) less than that of January in Shetland. The warmest 
month at Fort Franklin reaches 52°, or almost that of July in 
Shetland. The extremes are not less surprisingly different : — 
Extreme heat at Nova Zembla 49° F. At Fort Franklin 80° F. 
cold „ -53§ „ -58§ 

Range 102 138 

* Since this report was written, I had the satisfaction of seeing, at the Tenth 
Meeting of the British Association, the admirable observations of Mr. Calde- 
cott, at Trevandrum, in lat. 8° 30' N., which it may be hoped will soon be 
published. They are on the thermometer, barometer, and hygrometer, made 
hourly for three years. 

\ The reason, of course, being, that as the sun approaches perpetual appa- 
rition, the daily variation diminishes. There is an approximation to this at 
Leith. 

+ Von Baer, Tdglicher Gang., p. 9. 

§ The extreme of — 53 appears to be a very uncommon one at Nova Zembla, 
much more so than —58 in North America. Captain Back observed so great 
a cold as — 70°. 



SUPPLEMENTARY REPORT ON METEOROLOGY. 53 

Enonnous as both these ranges are, we cannot but observe that 
the Asiatic extreme warmth does not approach within 30° of 
the American one ! and yet the mean temperature of both sta- 
tions is nearly alike. 

41. The determination of the diurnal curve of temperature 
and its variations may be almost called complete, in comparison 
with that of the annual curve, which, notwithstanding, is a 
matter in some respects of still more important concern. Even 
the mean tempei-ature of a place, at any period, is very difficult 
to fix, owing to the great discrepancies of successive seasons. 
Thus 29 years, from 1806 to 1834, during which comparable 
observations have been statedly made at the Observatory at 
Paris, give a mean of 10°*822 cent., with a variation between 
one year and another from 12°'10c. in 1822, to 9°-35c. in 1829, 
the difference being almost 5° of Fahrenheit*. It is evident 
that many years must be required to fix even this comparatively 
simple datum ; how much more to determine the form of the 
annual curve which, in every region, is doubtless characterized 
by peculiar inflections ! 

42. The study of the annual curve is very much retarded by 
the want of simple, permanent, and comparable meteorological 
observations. These, which require little expense and little time, 
pre-suppose, from the extent of years over which they nmst 
extend, a kind of co-operation to which too little attention has 
been directed. The Paris observations are perhaps the only 
ones to which we can look with any degree of confidence in 
this respect, even for the comparatively short period of thirty 
years. Professor Brandes, of Breslau, has, with praiseworthy 
industry, collected and reduced a vast number of observations, 
continued at various stations for eight, ten, or more years, and 
has compared them and projected the annual curves, which he 
obtains by finding the mean temperature of successive periods of 
five daysf. The chief stations are Petersburg, Stockholm, Cux- 
haven, Zwanenburg, London, Mannheim, Vienna, St. Gotthard, 
La Rochelle, and Rome. In these curves, imperfect as they are, 
are well shown the peculiarities of insular and continental 
climates, and those of plains and mountains. Some points of 
agreement may probably be found in all, for which sufficient 
reasons may be assigned ; such as the more rapid increase of 
temperature than its decline, which applies equally to the diur- 
nal curve. This is, I conceive, chiefly owing to two causes, 

* Poisson, Theorie de la Chaleur, p. 463. 

t Beitrdge zur Witterungskunde, von H. W. Brandes. 8vo. 1820. Unter- 
nuchungen iiber den niittleren Gang der Warme-Aenderungen durchs ganze 
Jahr. 



54 REPORT — 1840. 

which I will simply indicate : first, that by its nature the 
absorption of heat due to direct radiation from the sun must go 
on more rapidly than the dissipation of it by cooling ; and 
secondly, that some influence may be attributed to the different 
distribution of vapour during the rise and decline of tempera- 
ture. 

43. Owing to these causes, thermometric curves, if they can 
be assimilated to symmetric geometrical curves at all, such as 
parabolas, must be regarded as having their axes oblique and 
not vertical. An erect parabola cannot even, generally speak- 
ing, be employed for finding the maximum with exactness on 
this account. But, in point of fact, no one parabola can repre- 
sent all the parts of the thermometric curves which, in their 
least complicated forms, approach more nearly to the curve of 
sines. 

44. From the tables of Brandes and others, we may infer 
the probability of discovering special inflections of the annual 
curve which characterize particular regions of the globe. The 
European curves point, for instance, with great distinctness to 
a check in the progressive rise of temperature, owing to the 
increasing power of the sun, which occurs almost invariably in 
the middle of February. This inflection of the annual curve, 
which in Eui'ope always bends it towards horizontality, and 
sometimes produces distinctly a second minimum in March, is 
a circumstance which has attracted too little attention, and as 
an indication of other general inflections deserves notice. This 
circumstance has lately been insisted on by M. Erman, in a 
letter to M. Arago*, who ascribes it, I think, with unwarrant- 
able boldness, to the interception of the solar rays by the j)as- 
sage of the meteors of November between the earth and sun ! 
I believe that it can be very easily accounted for, as occurring 
in Europe (which is all we know at present), by the periodic 
easterly winds of spring, caused by an unequal effect of tem- 
perature which we shall presently notice, and which almost 
invariably set in for a time at that season, bringing masses of 
cold air, from the continental regions of Europe and Asia, to 
the western shores f. 

• Comptes Rendus (Paris), x. 21. (1840.) 

f Since these pages were written, I have received from Prof. Dove of Ber- 
lin his elaborate Memoir " on the non-periodic changes of the Distribution of 
Temperature on the Earth's Surface," in which he has collected the most com- 
plete series existing of authentic observations of monthly mean temperature 
for fifty-nine stations. One of his conclusions is remarkable, viz. that when a 
large portion of the earth's surface is taken into view, the apparent irregularities 
of particular seasons counteract one another, so as to give no countenance to 
the idea, that more heat falls on the earth generally one year than another. 



SUPPLEMENTARY REPORT ON METEOKOLOGy. 55 

C. Isothermal Lines*. 

45. We will despatch very quickly what is to be said on the 
very important subject of climatology, because no material 
step whatever has been made since the publication of the last 
report. A considerable number of detached observations, of 
various degrees of merit, on the mean annual and monthly 
temperatures of many points of the earth's surface, have no 
doubt been added, and a list of many of these monographs may 
be found in Dove's Repertoriumf, and in the Transactions of 
the Meteorological Society. M. Kamtz has performed the use~ 
ful labour of amassing all the trustworthy observations of mean 
temperature which he could discover, and presenting the monthly 
means, in the second volume of his Meteorology. The German 
translation by Mahlmann of my former report, embraces figures 
on different projections of the isothermal and isogeothermal 
lines. Both of these, especially the last, require still the greatest 
attention, even to give an approximation to truth ; but we have 
not yet obtained the roughest sketch of the variations which 
these lines undergo with change of season ; in other words, of 
the isocheimal and isotheral lines | ; yet these are of the greatest 
practical importance. The distribution of animal and vegetable 
life materially depends on them ; the boundary of some plants 
being determined by the minimum winter temperature, and the 
advantageous cultivation of most by the extreme heat of sum- 
mer ; the limits of the vine, iiiaize, and olive depend on these 
circumstances ; and the region of barley so exactly coincides 
with the isotheral line, that (according to Wahlenberg) barley 
ripens wherever the mean temperature of ninety consecutive 
days rises to 48° Fahr. 

46. Professor Dove has not inaptly compared the annual 
variations of the form of the great system of isothermal lines to 
those which the Lemniscates formed in some biaxal crystals 
seen by polarized light undergo by changes of temperature§. 

47. These variations (to which we would particularly direct the 
efforts of meteorologists) are the more important, because, as 
we have already seen in treating of the form of the annual 
curve, places may have the same mean temperature, and yet 
their climates may have no real resemblance whatsoever (as 
when we compare the climates of Nova Zembla and Fort 
Franklin in North America, and those of Unst in Shetland and 
Copenhagen) ; and these characters may depend in a good 
measure upon local circumstances. Those who ai-gue about 

* Last Report, p. 214, &c. Mahlmann, p. 45. t '"• 266. 

J Last Report, p. 218. § L'Institut, No. 32.5. 



56 REPORT — 1840, 

the constancy or inconstancy of climates from ancient times to 
the present*, would do well to recollect that their criteria are 
almost all drawn either from extreme temperatures, or from the 
facts of botanical geographj?^, neither of which give true indi- 
cations of the mean annual temperature of a climate. 

48. From various remote regions we continue to receive in- 
teresting reports of the mean temperature, which seem gene- 
rally to be more carefully and consistently made than in stations 
of easier access. It is indeed surprising, in how few points of 
the civilized parts of Europe the mean temperature can be said 
to be known with any degree of exactness, to which the verifi- 
cation of thermometers is an indispensable preliminary. We 
may mention, as particularly interesting amongst observations 
in the most inhospitable regions of the globe, the observations 
at NovaZemblaf, Dr. Richardson's reduction of those of Parry 
and Franklin, the observations of Beechey, Ross, and Back, in 
their respective voyages, the last of whom observed the greatest 
natural cold yet registered |; Kupffer and Brewster § on the 
temperatures observed on the north-west coast of America, and 
Arago upon similar observations by Macloughlin ||. Mr. Web- 
ster has given a list of extreme winters observed in North 
America ^ ; and Dr. Daubeny some observations on the climate 
of that coimtry** ; Mr. Trevelyan has reprinted his paper on 
the Climate and Vegetation of Farve, with additions ff. 

49. We have already observed, that it appears, by a reference 
to the Paris Tables, that a long series of years of observation 
is required to obtain with certainty the mean temperature of a 
place J|. It is probable that the temperature of the ground is not 
liable to so great fluctuation, and therefore that kind of obser- 
vation should be made wherever practicable. This does not, how- 
ever, supersede the necessity of long-continued meteorological 
observations with verified instruments made under proper pre- 
cautions ; and we hope to see the Plymouth observations, and 
those conducted at the various magnetic stations fixed upon by 

* See on this interesting subject Arago, Anmiaire, 1834; Schouw on the 
Climate of Italy (Ed. Phil. Journal, July 1840), and an anonymous paper in 
the Phil. Mag.. Aug. 1840. 

t Supra Art'., 37—40. + Ibid. 

§ Phil. Mag., 3rd Series, i. 427. || Comptes Rendus (Paris), i. 266. 

^ Silliman's Journal, xxviii. 183. The valuable Meteorological Reports from 
the State of New York are still continued, and, through the kindness of Dr. 
Romeyn Beck, I have received them down to 1837. 

** Brit. Assoc, Eighth Rep., Sect. p. 29. -f-f 4to. Florence, 1837. 

XX The longest extant series of meteorological observations worthy of any 
ronfidence is probably that atBei-lin, printed in Dove's paper on Non-periodic 
Variations of Temperature (Berlin, 1840). It extends from 1719 to 1839 ; the 
greatest annual temperature was 9'''69 R. in 1756 : the least 4°-38 R. in 1740. 



SUPPLEMENTARY REPORT ON METEOROLOGY. 57 

the British government, continued for a series of years on this 
account. M. Boussingault has remarked, that at the Equator 
the mean temperature of any place may be found at any time of 
the year, and at any hour of the day, by digging a pit in a 
shady spot a foot deep, and observing the temperature at the 
bottom of it*. M. Poisson considers this result as conform- 
able to theory f. It is, at all events, a most convenient fact, 
and adds one to the many encouragements which nature affords 
to the prosecution of meteorology in tropical regions, where 
hitherto it has been most neglected. 

50. The improvement of our knowledge of terrestrial tempe- 
rature is a most important branch of science. It may be doubted 
whether it has hitherto been cultivated in the right way, and 
whether local and minor anomalies have not been allowed to 
conceal the general laws which we should first seek to attain. 
It is quite certain, that the causes producing the inflexions of 
the isothermal lines are of the most irregular and unmathe- 
matical character, such as the boundaries of coasts and the like. 
Still we think that the time may not be far distant when we 
shall have isothermal charts as superior to those now existing, 
as Gauss's magnetic charts, deduced by skilful artifices from a 
limited number of good observations, are to those of Halley in 
the last century. 

D. Decrease of Temperature ivith HeightX- 

51. Part of what properly belongs to this head will be more 
conveniently treated of in considering the general question of 
the temperature of the globe and its appendages. 

52. There is little doubt that the decrement of temperature 
is not uniform, but slower as we ascend. It is to this, pro- 
bably, that we are to ascribe the greater values of the height 
due to 1° of decrement in equatorial than in temperate climates: 
thus, Boussingault found 26° c. of decrement for 4800 metres 
of ascent in the tropics, or . . . 1° c. for 184 met. 

Col. Sykes, in India, on a height of 

8500 ft., finds 1° F. for 332 ft. of 

ascent §, or l^c. „ 182 „ 

Whilst Saussure's mean value in the 

Alps is l°c. „ 154 „ 

Eschmann on the Rigi . . . l°c. „ 151 „ 

* Ann. de Chim. liii. Annuaire, 1 836, p. 263. 
+ Theorie de la Chaleur, p. 508, &c. 
I See First Report, p. 218, and Mahlmann, p. 53. 
§ British Association, Fourth Report, p. 568. 



58 REPORT — 1840. 

M. Boblaye in Greece . . . Pc. for 150 met. 
38 observations collected by Ramond l°c. „ 164*7 „ 
And for Gay Lussac's aerostat alone l°c. „ 184 „ 
as we might expect, from its great elevation*. 

53. We have reason to believe, that in high latitudes the 
decrement is less rapid than in low ones; and M. Aragof has 
called particular attention to cases in which an actual inversion 
of the usual law occurs in the latitude of Spitzbergenif, and on 
Arthur's Seat, near Edinburgh, during extreme cold§. 

54. The decrement of temperature in the atmosphere, with 
reference to its constitution, has been considered in a lengthened 
series of papers, of which we cannot attempt an analysis, by 
M. Biot, lately published in the Comjites Rendus de V Academie 
des Sciences de Paris, and in the Connaissance des Terns. 

55. It has been considered in a more restricted point of view 
by Prof. Challis||, who has deduced from the properties of air, 
with regard to specific heat, a fall of 1° Fahr. for 186 feet, 
which is about a half too rapid. Mr. Lubbock, on the other 
hand, proceeding a jjosteriori from Gay Lussac's aerostat, has 
generalized the connexion of temperature and pressure so as to 
find the height of the atmosphere^. 

56. Any attempt, however, to connect the temperature and 
density of the atmosphere by laws such as regulate a laboratory 
experiment, must fail, in consequence of the incompleteness of 
the data. The increased specific heat of rarefied air is by no 
means the only cause of the diminished temperature of the 
higher regions of the atmosphere**. The higher the stratum, 
the more transcalent the medium which separates it from the 
planetary spaces, and therefore the freer will be the radiation in 

* To convert metres for 1° cent, into English feet for 1° Fahr., use the con- 
stant factor 1-8227 [log. 0'26072]. 

f Comptes Rendus, vii. 206. 

X Observed by Captains Sabine and Foster. 

§ Observed by Dr. Lind, 31 Jan. 1776. Phil. Trans. 1777. 

II Cambridge Transactions, vol. vi. 

% On the Heat of Vapours, p. 21. Lond. 1840. 

** On the specific Heat of Gases, see Dr. Apjohn's experiment by the use of 
the moist bulb hygrometer, (Brit. Assoc, Sixth Rep., Sect. Proceedings, p. 33,) 
and .Suerman's Thesis, De Calore fluidorum elasticorum specifico, 4to. Trag. 
1836, for which I was indebted to tjfie ever-ready kindness of our late associate 
Dr. Moll. In these essays we find a new proof of the inexhaustible ingenuity 
by which philosophers have endeavoured to make amends for the practical dif- 
ficulties of the direct problem : it is curious to see one and the same question 
treated, now by the aid of the calorimetei-, now by observing the tone of an 
oi'gan-pipe, and now by a dew-point experiment! Unfortunately, we cannot 
add that these varioiis methods give the desired concordance of result. Re- 
gnault's are the latest experiments on the specific heat of simple^bodies. Ann. 
de Chim. Ixxiii. I. (1840.J 



SUPPLEMENTARY REPORT ON METEOROLOGY. 59 

that direction. Besides, the atmosphere is no doubt a medium 
of that description, which permits solar radiation to pass much 
more freely than heat which has combined with the materials of 
the globe at a low temperature ; hence the surface of the globe 
may be considered as a true accumulating source of heat, the 
further we recede from which the greater will be the cold*. 

57. A just apprehension of these circumstances will serve to 
explain the modifications of this phajnomenon, as well as the 
phaenomenon itself. This I have lately endeavoured to do, and 
to show the accordance of the theory with facts f. It is known, 
from experiment, that the decrement of temperature is most 
rapid in spring, and least so in autumn. This appears, both 
from the reduced observations on the Pentland Hills, near 
Edinburgh, alluded to in my last Report (p. 219), and from 
those on a great scale, conducted so long at Geneva and the 
Great St. Bernard J. I have shown that this arises from the 
following peculiarities of the annual curves at two stations at 
different elevations ; (1 .) the curve at the upper or colder station 
stands wholly below that at the warmer one. Hence were these 
two curves similar, and their epochs the same, the difference 
would be constant. But (2.) the rcaige at the upper station is 
less than that at the lower one ; hence the summer difference of 
temperatures is on the whole greater than the winter difference, 
which we know to be the fact§. (3.) The maxima above occur 
later than those below, so that the whole colder and flatter 
curve is shifted to the right hand, and hence the epoch of 
maximum difference precedes the epoch of maximum tempera- 
ture, according to a law which I have investigated in the paper 
referred to. 

58. The diurnal curves correspond to the annual curves in 
the two first particulars, but not in the last. I have attempted 
to explain the cause of this difference, and to show that, in 
point of fact, the epoch of the diurnal curve at the higher 
station is (up to a certain height at least) accelerated upon the 
lower one instead of the reverse, and that consequently a re- 
tardation of the maximum difference upon the maximum tem- 
perature occurs, which is really the case||. A clear apprehen- 
sion of the progress of temperature in the atmosphere and 

* See on this subject Fourier, Mem. de I'Academie des Sciences, torn. vii. ; 
Ann. de Chim. xxvii. 155 ; Saussure, Voyages dans les Alpes, 4to, torn. ii. § 932, 
&c. ; Kamtz, Lehrhuch, ii. 128; Pouillet, Comptes Rendus, vii. 49. 

t Edinburgh Transactions, xiv. 489 (1840) ; and Jameson's Journal, 
October 1840. 

X Dove's Kepertorium, iii. 337. 

§ See First Report, p. 219. Kamtz, Lehrhuch, ii. 140. 

II Saussure, Voyages, iv. § 2050. Kamtz in Poggendorff, xxvii. 345. 



60 REPORT 1840. 

earth leads to itiany interesting and important practical con- 
clusions, upon which we cannot now dwell. 

59. Whilst we admit the phfenonienon of the decrease of 
temperature with height to be the normal one, and other cases 
exceptions, we must not omit to mention an important class of 
real exceptions, which deserve particular study. 

60. The superior radiating power of Earth to Air is the 
cause of the seemingly preternatural depression of the tempera- 
ture of the ground in clear evenings observed by Six, Wilson, 
and Pictet, and so well applied by Wells to the theory of 
dew. It is evident, that under the circumstances which favour 
the development of the cause (viz. Radiation), the effect must 
extend more or less above the surface ; and, consequently, up 
to a certain point the temperature will increase with height. 
This question has lately been treated of in an interesting paper 
by Prof. Marcet*, who has arrived at the following con- 
clusions: — 1. It is a constant phsenonienon about the time of 
sunset, except in the case of violent winds. 2. It attains a 
maximum immediately after sunset. 3. The increase of tem- 
perature with height extends to 100 or 110 feet at the most. 
4. It is most conspicuous when the ground is covered with 
snow. 

61. This leads us directly to the important subject of 

E. Radiation f, 

whether solar or terrestrial ; in its bearings, perhaps, the most 
important and interesting at present connected with Meteoro- 
logy. We speak now principally of instruments and primary 
results ; in the next section, of conclusions to be drawn from 
them in connexion with great cosmical questions. 

62. The earth acts by absorbing radiant heat from the sun 
and (perhaps) other heavenly bodies ; and it radiates it again 
according to new laws towards space. Each of these effects, and 
the modifications which circumstances introduce into them, may 
be made the subject of separate experiment. 

63. Since a thermometer with a blackened ball absorbs more 
solar heat than a bright or transparent one, it was natural to 
suppose that the difference of indication of two such instru- 
ments might be considered as a measure (at least a relative 
indication of the force) of solar radiation. The stationary dif- 

• Memoires de la Societe de Physique, &c. de Geneve, torn. viii. (1838). 

t See First Report, p. 222 ; Malilmann, p. 64. I think it unnecessary to say 
anything of the progress of our knowledge of Primary Physical Laws of Radia- 
tion, because that is to be made the subject of a special report by Professor 
Powell. 



SUPPLEMENTARY REPORT ON METEOROLOOy. 61 

ference of such instruments was therefore observed by Lam- 
bert*, Leslie t, and others. 

64. It is plain, however, that this indication can only be con- 
sidered to be comparable with itself so long as all external cir- 
cumstances besides solar radiation remain the same. This 
Saussure well showed by one of his admirable experiments t, 
in which, by properly defending the thermometer from wind and 
common radiation, he raised its temperature in the sun to 190° 
Fahr. Sir John Herschel first pointed out that the momentary 
effect of the sun and other combined causes, in affecting the 
temperature of a thermometer, diminished by the momentary 
effect of those other causes acting separately, is the true relative 
measure of the force of the sun's rays. The first notice I have 
met with substantiating Sir John Herschel's claim to the ap- 
plication of this principle (which has since been rather un- 
scrupulously adopted abroad with a slight change of form), 
is in a paper by the late Dr. Ritchie, in the Edinburgh Journal 
of Science for 1825 §, where he gives an extract from a letter of 
Sir John Herschel, who, in a few words, sufficiently describes the 
instrument and its principle. Full instructions for its use have 
lately been printed by the Royal Society || 5 it is called an ac- 
tinometer. 

65. The actinometer scale is an arbitrary one, obtained by 
direct comparison of one instrument with another; and so satis- 
factory is this kind of observation, that, from direct experiment, 
I am satisfied that the value of the actinometric degrees may be 
obtained within y^oth of the amount of solar radiation. It is 
very singular, that Sir John Leslie, with his marked sagacity, 
should not have perceived that his mode of graduating photo- 
meters, by first converting them into hygrometers^, is radically 
erroneous ; and accordingly I have found that, when his instru- 
ments are compared, after being constructed with the utmost 
care, they do not even approach to agreement except at 0°, 
unless they are of the same dimension, and in every respect 
similar; but absolute identity in size, material, and arrange- 
ment, it is beyond the power of art to obtain. Careful experi- 
ments, which I have likewise made with this elegant instrument 
under different skies and in different climates, compel me to 
conclude, that though in certain very uniform circumstances 
its relative indications may be really of value, yet in a wider 

• PyromUrie, p. 158. 4to. Berlin, 1779. 

+ Essay on Heat. Lond. 1804. t Voyages dans les Alpes, § 932. 

§ Vol. iii. p. 107. 

II Report of Committee of Physics, &c. 1840, p. 61. 

4 Essay on Heat, p. 421. 



62 REPORT — 1840. 

point of view they do not even afford the slightest approxima- 
tion to the truth. 

66. It does not, however, follow that the indications of the 
photometer are of no value, or that observations with it should 
be discontinued. There are some constant peculiarities in its 
action, so remarkable, as to suggest very interesting investiga- 
tions. The effect of the reflected light of the sky is always 
exceedingly intense ; so much so, as to give rise to the most 
paradoxical effects with regard to the intensity of solar radia- 
tion, if neglected. Thus I have found the whole effect of the 
sun and sky in a bright April day in this country, when many 
white clouds were present, not very inferior to that of the most 
piercing sunshine of the most sultry day of the south of Europe, 
unaccompanied by a single cloud. What would be the indica- 
tions of the actinometer in these circumstances I am unable to 
state. M. Kamtz found, on the sumi\)it of the Faulhorn, that 
the direct solar effect on Leslie's photometer was equalled, 
and often exceeded, by that of the diffuse atmospheric in- 
fluence*. 

67. Sir John Herschel has lately proposed to render his scale 
an absolute one, denoting by an actine " the intensity of solar 
radiation, which, wholly absorbed at a vertical incidence, would 
suffice to melt a sheet of ice one-millionth of a metre in thick- 
ness in one minute f." With an actinometer, which marked 
29°-5 as the maximum effect which he had obsei*ved in Europe, 
Sir John Herschel found the solar radiation at the Cape of Good 
Hope to attain 48°-75 of the same scale, the intensities being 
in the exact proportion of those numbers J. 

68. M. Pouillet, of Paris, described, some years ago, an ap- 
paratus for measuring solar radiation, in which the errors of other 
statical contrivances were in a good measure avoided, by en- 
closing the thermometer in an envelope maintained at 0° c, with 
the exception of a small hole, which exactly admitted the direct 
rays from the solar disc§. Since that time, however, he has 
adopted Herschel's dynamical method, which he has applied to 
a modification of the actinometer, which he terms a pyrhelio- 
meter ; reserving (rather unfortunately I think) the term acti- 
nometer, which was already so fitly appropriated, to a separate 
apparatus for measuring nocturnal radiation. These instru- 
ments and their applications are described in an ingenious and 
interesting memoir read to the Academy of Sciences 9th July, 

* Lehrhuch, iii. 14. 

t PoggendorfF, xli. 559. Royal Society's Report, p. 67. 

+ Comptes Rendus (Paris), iii. 506. 

§ Elemefis de Physique, 1832, torn. ii. p. 703, fig. 356. 



SUPPLEMENTARY REPORT ON METEOROLOGY. 63 

1838, printed in the Comptes Rendus*, and also privately cir- 
culated. 

69. A question of very great importance in meteorology, and 
one of the first which radiation experiments were employed to 
determine, is the proportion of incident solar heat which is 
absorbed in its vertical passage through the atmosphere. In 
the acute, learned, and original work of Lambert on Photo- 
metry, published in 1760, (and now, I know not why, extremely 
scarce,) this question is fully discussed ; formulfE are investi- 
gated for the total loss of light at any altitude, according to an 
assumed law of density, (which had already been done by Bou- 
guert, who first suggested the method,) and from a comparison 
of intensities at two elevations, the total loss in the atmosphere 
by a vertical transit is ingeniously deduced];. From experi- 
ments made at Coire with blackened thermometers, Lambert 
deduced the loss of light or heat by a vertical transit through a 
clear atmosphere to be about y%ths of that incident on the ex- 
terior boundary §. Bouguer had estimated the loss of light at 
only one half as much. 

70. Laplace || investigated the law of extinction of light in the 
atmosphere, and showed that it may be made to depend ap- 
proximately on the measure of refraction at any angle, by a very 
simple formula. He employed Bouguer's constant for OP of 
zenith distance. 

71. Sir John Leslie made experiments on the principle of 
Bouguer and Lambert, with his photometer placed in a position 
which equalized as much as possible the coolhig causes, and 
admitted the direct heat of the sun<^. The results are con- 
tained in the article Climate, in the Encyclopaedia Britannica, 
from which it appears that he estimates the loss of heat by 
absorption at \t\\ of that vertically incident. 

72. Professor Kamtz, who has done full justice to Leslie's ele- 

* Memoire sur la Chaleur Solaire, sur les pouvoirs rayonnants et ahsorlanfs 
de I'Air Atmospherique, et sur la Temperature de VEspace.— Comptes Rendus 
vii. 24. ' 

t Traite d'Optique, &c. 4to. 1760, p. 306. Bouguer restricted his method 
to a comparison of the intensity of hmar light at different elevations with wax 
candles. 

X Lambert, Pkotometria, she de Mensura et gradihns Luminis, Colorim et 
VmhrcB, p. 392, &c. ' 

§ Photometria, p. 397. Compare Pyrometria, § 283. 

II Micanique Celeste, iv. 282. 

1[ Sir John Leslie himself gives no account of the circumstances under which 
the observations were made, but I learn from his assistant, that the photometer 
was placed under the revolving dome of the Edinburgh Observatory, the slit 
being turned towards the sun, and that it was observed very frequently at dif- 
ferent hours. 



64 REPORT — 1840. 

gant instrument*, and who has endeavoured to separate from its 
indications that part which is due to reflexion from the at- 
mosphere, finds by it, that at the summit of the Faulhorn, 
nearly 9000 feet above the sea, 30 per cent, of the vertical rays 
are already lost. With Herschel's actinometer (calculating al- 
ways observations at diff'erent elevations by Lambert's formula), 
he obtains only 26 per cent, of loss at the Faulhorn, or 32 per 
cent, at the level of the sea. This was in perfectly clear weather. 

73. M. Pouillet, employing likewise Lambert's formulae, and 
the modification of the actinometer already mentioned, finds, at 
different seasons of the year, an absorption varying from 21 to 
28 per cent., at a vertical incidence at Paris. 

74. Saussure seems first to have thought of comparing directly 
the intensity of solar heat at the top and bottom of a mountain, 
and he contrived a heliothermometer for that purpose ; and by 
experiments on the Cramont, to the south of Mont Blanc, he 
actually proved the increased intensity of the solar rays as we 
ascend, notwithstanding the diminution of temperature; un- 
doubtedly a very remarkable experiment for the period f. 

75. In 1832, Sir John Herschel kindly pointed out this pro- 
blem to my attention, and furnished me with two actinometers. I 
had the rare, good fortune to obtain the aid of Prof. Kamtz in 
making directly comparative experiments at the top and bottom 
of a column of air 6500 feet high, of known density, tempera- 
ture, and humidity, under the most unexceptionable circum- 
stances in point of weather. A provisional reduction of these 
experiments has given me 29 per cent, for the vertical loss at 
the level of the sea, a near agreement with the 32 per cent, in- 
dependently determined by the method of Bouguer and Lam- 
bert with the same instrument at the same time. 

76. Collecting these various results, we have for the absorp- 
tion of incident solar heat traversing the atmosphere vertically 
in clear tveather, the following fractions (incident heat = 1) : — 

Bouguer '19 

Lambert "41 

Leslie -25 

Kamtz -32 

Pouillett -25 

Kamtz and Forbes '29 

Mean -285 

Mean, omitting the two first . '277 

* Lehrluch, iii. 10, &c. f Saussure, Voijages, 4to. iii. 310, and note. 

X It appears from the remark of M. Pouillet, p. 8 of his Memoir, that he 
■;70uld make the fraction even lower for a perfectly pure sky. 



SUPPLEMENTARY REPORT ON METEOROLOGY. 65 

77- Another method of measuring, or at least comparing the 
intensity of solar radiation^ would be by the use of photographic 
paper*. 

78. The next problem which radiation experiments may be 
expected to solve, is the quantity of heat actually received from 
the sun in a year on the surface of the earth. According to 
Pouillet's last estimate, this amounts to a quantity of heat 
capable of melting 31 metres' thickness of ice all over the 
globe f. Such estimates must be received with considerable 
diffidence. 

79. The excess of heat received during the day is given off at 
night, or rather there is a perpetual radiation of heat from the 
globe towards the celestial spaces, which, granting the con- 
stancy of climate from age to age, must exactly equal the quan- 
tity of heat received. Observations of this kind may be made 
in various ways. The simplest is by exposing a thermometer 
to the aspect of the open sky, laying it on some freely radiating 
substance, such as snow, wool, or swandown. In this manner 
were conducted the experiments of Six, Wilson, and Wells. 
Wells noticed a difference of two thermometers, one in air, the 
other placed on swandown, amounting to 8*3 centigrade de- 
grees J (15° E.). Boussingault, in his observations amidst the 
Andes, has recorded a depi'ession of 6°"1 ; but the radiating 
thermometer was laid simply on turf, the other was suspended in 
the air at a height of 1*6 met. (5 ft. 4in.)§. His observations 
were carried to a height of 4600 metres, where we should expect 
the effect of nocturnal radiation to be gi*eatly increased, owing 
to the excessive transparency of the atmosphere. The same 
author mentions the curious fact, that to defend their crops 
from the intensity of the nocturnal cold, the natives of South 
America often make artificial clouds by means of smoke. 

80. Leslie applied his differential thermometer to the measure 
of radiation by exposing one ball in the focus of a parabolic 
mirror, which he then called an ethrioscope. The conduct of 
systematic experiments of this kind is a matter of considerable 
difficulty. The only continuous series with which I am ac- 
quainted were made at Geneva during several years succeeding 
1836, and published amongst the regular and excellent obser- 
vations preserved in the Biblioth^que Universelle, a journal in 

* See Hei-sche], Phil. Tvans. 1840, p. 46. "Description of an Actinograph 
or self-registering PhotoD\eter for Meteorological purposes." 

t Memoire sur la Clialeur Solaire, p. 9. His former estimate was 14 metres 
only (see First Report, p. 222). 

J Arago, Annuaire, 1836, p. 261. See also Annuaire, 1833, p. 214, &c. 

§ Ann. de Chim. lii. 260. 
VOL. IX. 1840. F 



66 REPORT — 1840. 

which, during its long existence, marked attention has been 
given to the science of meteorology*. It does not appear, 
from the writings of Sir John LesUe himself, that he had ever 
obtained any very definite results by the use of the ethrio- 
scopef. The action of the reflecting mirror seems not to be 
fully understood, at least so M. Pouillet asserts it* I ^'^ 
unable, from experience, to verify his statement, which 
leaves, however, some ambiguity. M. Pouillet employs 
a vessel stuffed with swanskin {peau de a/gne), capable of 
having its orifice directed at pleasure, and having a radiating 
thermometer in its centre. By ascertaining the effect upon 
this apparatus of a surface artificially maintained at a given 
temperature, he deduces the mean radiating temperature of the 
atmosphere considered as an indefinite concave. But this 
brings us to general questions of great interest and importance. 

F. Proper Temjyerature of the Globe and of Space ^. 

81. I forbear to repeat what I have formerly said respecting 
the proofs of the proper temperature of the interior of the earth. 
I confine myself to a statement of the very important advances 
since made, both in experimental researches and in the induc- 
tion of laws. 

82. A fevv fundamental experiments are sufficient to maintain 
Fourier's position, that the interior heat of the earth exercises 
no perceptible influence on its present climate ; we are there- 
fore left to consider the effects of heating and cooling influences 
wholly external. 

83. The imperfect transparency of the atmosphere stops a not 
inconsiderable share of the solar rays, which are therefore ex- 
pended in heating it directly. But the major part reach the 
surface, and their effect being there concentrated (whilst in 
their transit through the atmosphere it is spread over a vast 
mass of air), the effect is incomparably more intense than else- 
where. The bounding surface of the earth (or ocean) and air is 
therefore to be considered as a true source of heat. From 
thence it is distributed progressively downwards by conduc- 
tion ||, upwards by RADIATION and convection. The warmth 

* Bih. Univ., N. S., iii. 209, and subsequent volumes. Since the publication 
of the formei" report, we have to regret the loss of the late amiable Sir. George 
Maurice, principal editor of that journal. 

f Articles Climate and Meteorology, Encyclopeedia Brilannica, New Edit. 

: Mem. Chal. Sol., p. 32. 

§ First Report, p. 221 ; Mahlmann, p. 67, &c. 

II Even in water. See the interesting and conclusive experiments by M. 
Despretz, Comptes Rendns, vii. 9.33. 



SUPPLKMENTARY RKPORT ON METEOROLOGY. 67 

of summer and the winter's cold are gradually propagated 
both upwards and downwards j and, in either case, with a 
diminishing intensity according to known laws. The annual 
curve of temperature in the ground is rapidly retarded and 
flattened, until, at a moderate depth, (60 to 100 feet, depending 
upon the conducting power and specific heat of the soil,) it 
sensibly coincides with a straight line, or the influence of 
seasons disappears ; and the same takes place in the atmosphere 
at a great and unknown elevation. 

84. The general principles of the communication of heat have 
led to the conclusions, 1. that the annual range should diminish 
geometrically as the depths below the surface increase arith- 
metically; 2. that the retardation of epochs increases uniformly 
with the depth*. 

85. Both these conclusions of theory have been very satisfac- 
torily verified by the experiments mentioned in the former re- 
port f, and extended since. And what is still more important, the 
verification of these two simple laws includes the introduction 
of certain constants, which may thus be determined d posteriori, 
and the general solution of problems of terrestrial conduction 
obtained. 

86. Instead of merely citing the formulae in which the ex- 
pressions of the constants of our globe and system are involved, 
and which are found to express approximately the thermo- 
metric conditions of the strata of our globe near enough to the 
surface to be directly influenced by climateric changes, we will 
endeavour to trace, very generally, the kind of process by 
which mathematicians have attempted to reduce to law these 
most complicated and involved series of causes. In doing so 
we have a twofold object, which seems peculiarly congenial to 
the nature of such reports as the present ; first, to extricate 
from a chaos of symbols (which would deter most persons 
from even tracing the connection of the data assumed, with the 
results announced), such results as apply immediately to the 
physical investigation ; and secondly, to consider how far the 
really fundamental conditions of the problem have, or have not, 
been sacrificed to render the mathematical investigation practi- 
cable at all. 

* See the original works on Heat of Fourier (particularly il/e»z. de I'Institut, 
1821-22, p. 163) and Poisson, the elementary work of Prof. Kelland, and the 
Report by Prof. Whewell, on the Mathematical Theory of Heat. British 
Association, Fifth Report. 

■f- P. 221. The experiments on buried thermometers, near Edinburgh, 
were made in the grounds of Mr, Ferguson, of Raith, by his permission, but 
were suggested and directed by the late Sir John Leslie. See Whewell'e Re- 
port, p. 30 ; see also article Climate, Encyclopeedia Rritannica. 

F 2 



68 RKPORT— 1840. 

87. The uork in which the rigorous comparison of theory with 
experience in this most intricate inquiry has been most insisted 
on, is that of M. Poisson, of whose mathematical attainments 
it would be equally unnecessary and unbecoming in me to 
speak ; any criticisms I have to offer will therefore be confined 
to the second of the heads T have noticed above ; and to his 
writings* I will chiefly confine my attention. 

88. So far as the effect of solar heat is concerned, the a pri- 
ori solution of the problem of the temperature of any part of the 
earth's surface may be thus imagined : — (1.) The w/tole quantity 
of sunshine which falls on any part of the earth's surface in 
the course of a year is to be found, and also the law of its 
variation of force at different seasons. (2.) The part of this 
heat which becomes effecti^'e in heating the earth's crust is to 
be found by multiplying the amount by a constant depending 
upon the absorbent power of the surface. (3.) This quantity 
of heat thus reduced is propagated towards the interior, accord- 
ing to the laws of conduction, which again pre-suppose the 
knowledge of two constants proper to each soil, namely, the 
Conductivity and the Specific Heat. 

89. (1.) The measure of the quantity of sunshine received by 
any place in a year, and its distribution at different seasons, has 
been a favourite problem with mathematicians f. In ultimate 
analysis, it depends of course on the astronomical elements 
which affect the progress of the seasons, viz. the obliquity of 
the ecliptic (7), the latitude of the place (/x), the excentricity of 
the earth's orbit(a), and the longitude of the sun's perigee (ot);}:. 
But there are also elements quite as important as any of these ; 
the imperfect transparency of the air and its varying thickness, 
owing to differences of obliquity of the transmitted rays, and 
the condition of opacity depending on the weather. Neither of 
these are insignificant, neither of them compensatory ; both 
may be considered as functions of the hour-angle and fraction 
of the year, and the second is besides subjected to the most 
capricious changes. Yet of these elements theory has hitherto 
taken no account, and consequently the expression for the 
quantity of sunshine obtained, in terms of astronomical con- 
stants, with so much labour, we must hold to be nearly useless 
as a physical datum. It is vain to say, witli M. Poisson §, 
" Les lois d'absorption de la chaleur solaire a travers I'at- 
mosphere, les variations diurnes et annuelles sont egalement 

* Theurie Mathcmatique de la Chaleur, 4to. Paris, 1835, chap. xii. Sup- 
plement, 4to, 1837, and Compfes Rendns, iv. 137. 
f See a list in Kiimtz, Lehrhuch, i. 60. 
X In Poisson's Notation. 5 Theorie, p. 475. 



SUPPLEiMENTARY REPORT ON METEOROLOGY. 69 

inconnues, et Ton peut seulement supposer qu'elles sont peu 
co7isid(f rabies." We know, on the contrary, that they are so 
considerable, that, estimating the loss of radiant heat by a 
vertical passage through the atmosphere (76.) at only twenty- 
five per cent., at an angle of elevation of 25° the force of the 
solar rays would be reduced to a half, and at 5° to one-tiventieth 
part. We know, indeed, that the difference of the direct effect 
of a vertical and a horizontal sun is due to this cause alone, exag- 
gerated, of course, immensely by the variable meteorological 
state of the atmosphere, which again is a function of the lati- 
tude. 

90. (2.) The receptive power of the surface is a datum which 
we find it very difficult directly to determine, and which, since 
the quantity of sunshine cannot (as we have seen) possibly be 
directly computed, must be inextricably mixed up with it. _ It 
might be a question, whether, by covering a tolerably extensive 
surface of soil, in vphich thermometers are inserted, with a com- 
position of known superficial conductivity, this element might 
not become known. 

91 . (3.) The specific heat (e) and conductivity [k) of the soil are 
also inextricably mixed up together in the analysis ; but either 
becoming known, the other may be inferred from thermometric 
observations carried below the surface. The specific heat seems 
that best adapted for laboratory experiments ; M. Elie de Beau- 
mont has assigned 0-5614 for the value of c (that for an equal 
hulk of water being = 1)*, proper to the soil at the Observatory 
of Paris. 

92. To obtain the conductivity of the soil a posteriori, it is for- 
tunately not necessary that the preceding theoretical estimation 
of the distribution of sunshine should be correct ; but there are 
other estimates into which it essentially enters, and which iiiust 
therefore be received with corresponding caution. To facilitate 
reference to M. Poisson's work, I will show how the simple and 
very satisfactory observation of maximum and minimum tempe- 
rature of the earth's crust at given small depths (above the inva- 
riable stratum) may be made to yield a knowledge of some of 
the constants above referred to. 

93. Let the excess of annual maximum above annual minimum 
temperature at a depth p be expressed by A^ ; then 

log Ap=^ A+ Bpf 
^n which A of course denotes the log. range when ^ = or 

* Poisson, Supplement, p. 4. 

f M. Quetelet puts under this form M. Poisson's equation. — See the memoir 
referred to below. 



70 RKPORT — 1840. 

at the surface, and B determines the common ratio of the geo- 
metrical progression according to which the range diminishes. 
From observations with two thermometers at different depths, 
A and B may be obtained a posteriori. 

94. Now when we consult M. Poisson's work, we find that his 
equation(23.), page 497, which is equivalentto the preceding one, 
is thus composed. The quantity A, on which the superficial 
range depends, contains (1) astronomical constants of climate y, 
ft, a, ■sy already mentioned 5 (2) a temperature h depending on 
the mean force of the solar rays which have traversed the atmo- 
sphere and entei-ed into combination with the earth's surface by 
absorption at a given place*; (3) the constant of conductivity /c, 
and of specific heat c. 

95. The co-efficient B, on which the rate of diminution of the 
range depends, is fortunately a very simple quantity, involving 
neither astronomicalconstants, nor those proper to the superficies. 

It is, in fact, an absolute number multiplied ^y\/ -jT) ^"^ from 

a knowledge of it (by observations with two or more thermonie- 
ters) this quantity may be very readily and accurately deter- 
mined ; and it affords the onljr unexceptionable manner of ascer- 
taining the conductivity of the earth's crust on a large scale. 
Observations to this effect have, from time to time, been made 
by thermometers plunged more or less below the soil ; first, by 
Ott of Zurich, in l762t; secondly, by Leslie near Edinburgh ; 
thirdly, by Herrenschneider at Strasbourg^; fourthly, by Muncke 
at Heidelberg§ ; fifthly, by Rudberg at Upsala ; sixthly, by 
Arago at Paris ; seventhly, by Quetelet at Brussels. An ad- 

* Poisson, p. 480, where the definition of A is " Une temperature coiistante 
proportionelle a I'intensite de la chaleur solaire, telle qu'elle est a la distance 
moyenne de la terre au soleil et apres avoir traversee I'atmosphere pour avriver 
au point O." It must not, however, be forgotten, that it includes s, a constant 
of superficial absorption, and therefore varies from one point to another. See 
Poisson, p. 500. The quantity k is one of the most troublesome clearly to ap- 
prehend, and the dispersion (and sometimes permutation) of symbols throughout 
so large a work contributes to the ambiguity. I will therefore add, that in the 

value of/;, pace 480, namely,-; : : — —, £ is a constant of absorption for a 

' ' ° ' •" (A -h A|) a- '^ 

given soil, but which may vary with the incidence of the rays (p. 474) ; S is the 

product of an element of surface, and a quantity of heat in the condition in 

which the atmosphere has transmitted it (p. 475) ; X and Tvj denote the proper 

superficial radiating power of the point O under consideration, and the cooling 

effect due to the contact of air (p. 349). The product of A by Q (see Art. 105, 

note) measures the thermometric efficiency of the solar rays in raising the 

climateric temperature of the spot (p. 518). 

t Lambert's Pyrometrie, p. 356. + Imperfect ; only one thermometer. 

§ Gives only the epochs. 



SUPPLEMENTARY REPORT ON METEOROLOGY. 



71 



mirable abstract and analysis of all these observations has been 
made by the last-named indefatigable observer, in a special me- 
moir on the subject*, which we could hardly abridge without 
transcribing, and will therefore state chiefly the results with 
respect to the quantities A and B mentioned above. The fol- 
lowing are the principal results in a tabular form, it being un- 
derstood that in most of these cases no correction has been ap- 
plied for the temperature of the liquid in the stem of the ther- 
mometer and betw^een the bulb and the surface of the ground. 



Place. 






Extreme 
Depth. 


Calculated Depth 
at which the 

Annual Range 
is reduced to 
oo-oi cent. 




Value of B. 


"5§| 

•G Mj! 

= §.■2 




8 
4 
1 
3 
4 
7 


4^ 

2 

3 

4 
3t 


feet. 

6(Fr.?) 

8(Eng.) 

15 (Fr.?) 

3 

25 (Fr.) 
24 


feet. 

71 

58 
81 
62 
69 
76 


1-217 
1-068 
1-279 
1-292 


- -038 

- -052 
--040 

- -053 


days. 

5-7 
7 

6 

6-7 


Edinburgh 

Strasbourg 




1-376 - -049 
1151 - -041 











96. The following observations have been made at Edinburgh, 
under my direction, at the expense of the British Association|, 
which, as well as those at Brussels, are completely corrected for 
the temperature of the liquid in the stems : — 



Edinburgh 
















In Trap Tufa. 


4 


3 


24 (Fr.) 


55 


1-141 


- -057 


6-8 


— Loose Sand. 


4 


3 





66 


1193 


- -048 


6-2 


— Sandstone. . 


4 


3 


— 


96 


1-080 


--032 


40 



97. These latter observations show very clearly the effect oisoil 
in determining the velocity of propagation of heat which mainly 
depends upon the value of B, from which too the conductivity for 
heat of three very different geological formations may be accu- 
rately determined, so soon as the specific heat shall be known. 

98. Observations of the same kind with the preceding have 

* Memoire sur les Variations Diurne et Annuelle de la Temperature, &c., 4to, 
Bruxelles, 1837. (From the Memoires de I'Arademie de Bruxelles, torn, x.) 

t These ohservations have now been continued for three additional years, and 
the partial results are contained in the Bidletin de I'Acad. de Bruxelles, and 
the Annuaire de I'Ohservatoire. Since this report was read, I have received 
M. Quetelet's Systematic Reduction of the Observations at Bruxelles for 1837, 
1838 and 1839. The results agree extremely well with those of previous years, 
and establish the formula of Art. 93. with remarkable precision. Mem. de 
I' Acad, de Bruxelles, torn. xiii. 1840. 

X See Eighth and Ninth Reports, and Athenaeum for September 1839. 



72 KEPORT— 1840. 

been instituted at Bonn by Prof. Bischoff*, and at Freiburg in 
Saxony by Prof. Reich f; but of these, so far as I am aware, 
only impei'fect notices have yet appeared. 

9,9. The epochal retardations for the annual curves at the depth 
of a few feet follow, generally speaking, a simple law, for they 
are propagated uniformly downwards with a velocity which is 
easily connected with the constants proper to the soil determined 
from the range at two given deptlis, as just explained|. It must 
not be concluded, however, that the epochs of earth-temperature 
at the surface coincide with those of air- temperature in the ad- 
joining stratum. The difference of epoch may be obtained in 
terms of the conductivity and superficial characters of the solid 
stratum§. But the complete expression for the epoch at any 
depth in terms of the dates of maximum and minimum at some 
other depth, and of the constants of conductivity and surface, 
derived from two observed ranges, is so complex, that so far as 
I know, no attempt has been made to verify IVI. Poisson's for- 
mulae except in a single example by himself, taken from M. 
Arago's observationsl|. 

100. It is a matter of some practical difficulty to find the 
precise period of maximum and minimum temperature from ob- 
servations at or near the surface, on account of the accidental 
fluctuations which occur, especially near the time of minimum, 
and which, even at a depth of three feet, produce in this climate 
an uncertainty sometimes of a week or more. 

101. I have already stated, in the preceding table, the results 

* Wdrmck/ire von G. Bisclioff, 8vo, 1S37, pp. 100, 392, 507. Tlie observa- 
tions were not made with long-tubed tliermometers having their scales above 
ground, bnt by sinlcing bottles of water in wooden tubes to a certain depth, 
drawing them up rapidly, and observing theiv temperature. The observations 
were carried to a depth of .'36 feet. 

t Bischoff, ibid, p. 512. 

X Poisson, p. 432. If X be the range at a depth x, and X' at depth x', and 
h the retardation of epoch due to the increased depth from x to x', tiie following 
relation holds, 

X'=Xe-"'^ 
m being a constant and e the base of Napier's logarithms. 

§ Ibid. 

II P. 502-3. The coincidence is not so remarkable as a cursory inspection 
would suggest; there are not four coincidences but only two — the data and 
qucesita being reversed. The coincidence, such as it is, perliaps jU^'Ot'e* too much ; 
for M. Arago's observations are not corrected for the ttmperatiue of the stem 
("afin de pouvoir faire usage des observations non corrigees que M. Arago 
m'a commvmiquees, je supposevai que ces corrections soient pen considerables," 
p. 500) ; it is certain, however, that for the larger thermometers, where the 
range is least, and the correction (jreatest, the epochs must be (perhaps most 
materially) affected. The scientific world anxiously looks for the extended and 
reduced observations of M. Arago. 



SUPPLEMENTARY REPORT ON METEOROLOGY. 



73 



of different observations on the rate of progress of heat into the 
soil, especially as depending on its geological character, a com- 
pact sonorous sandstone transmitting heat at the rate of one 
foot in four days, whilst in loose sand (the same ingredient) it 
required 6'2 days. The following tables illustrate the varying 
retardation and proportionate diminution of amplitude (or range) 
at different depths*. 



i 


Maximum. 


Minimum. 


Range. 


Trap. Sand. 


Sandst. 


Trap. 


Sand, j Sand>t. 


Trap. Sand. 


Sandst. 


3 

6 

12 

24 


Aug. 5 Aug. 2 
Sept. 1 Aug. 25 
Oct. 15 Oct. 8 
Jan. 6 Dec. 31 


Aug, 7 
Ag.l9 

Sept. 14 
Nov. 6 


Mar. 6 
Mar. 20 
Apr. 25 
July 15 


Feb. 28 
Mar. 22 
Apr. 22 
July 1 


Feb. 23 
Mar. 3 
Mar. 2G 
May 12 


l9°-67c ir-03c 
G°-12 8° -05 
2° -85 4° -03 
0° -75 l°-00 


9= -670 
7° -68 
5° -01 
2° -20 



102. What we have now stated respecting annual variations of 
temperature, is found to be true, mutatis mutandis, for diurnal 
ones. Theory shows that the depth at which periodic fluctua- 
tions sensibly vanish should be [cceteris paribus) as the square 
roots of their periods, and this is found to be nearly the case in 
point of fact ; the diurnal oscillation being nearly as insen- 
sible at a depth of three or four feet, as the annual one is at nine- 
teen (or \/ 365) times the depth, or at 60 or 70 feetf. M. Que- 
telet has made a most extensive series of observations at small 
depths, and he finds the diurnal heat- tide to penetrate at the 
rate of 1 decimetre (4 inches) in 2*8 hours nearly, in the month 
of MarchJ. 

103. We now hasten to state a few other conclusions which 
have been attempted to be drawn from the very important class 
of observations of which we have recently spoken. Did we 
possess, in the actinometer or any other instrument, the 
means of measuring the actual force of sunshine in any place at 
a given moment, insuperable difficulties would yet arise to the 
determination of the very important questions, " To what extent 
does the direct solar influence actually contribute to produce 
the climate we enjoy ?" and " What would be the temperature 
of our globe without the sun ?" It is difficult or impossible 
for us to take cognizance of the perpetually fluctuating amount 
of solar heat, and to sum up the discontinuous amount of it du- 
ring the year, allowing for intervals of darkness, atmospheric 

• These nuuibers are (excepting the epochs of minima, Avhich are but two 
years) a mean of three years. The temperatures are centigrade. 
+ Quetelet, ut supra, p. 72. :j: Ibid, p. 68. 



74 REPORT 1840. 

opacity, and cloudy weather ; and even could this be accom- 
plished, we should yet want data for knowing what portion of 
the incident heat combines with the earth so as to affect the 
climate. M. Pouillet, we have seen, has estimated the total 
quantity of sunshine incident on our globe*, but this was irre- 
spective of modifications of weather, and of the variable quantity 
of sunshine in different latitudes. 

104. A practical a jjosteriori determination of this most im- 
portant meteorological element of the total quantity of effective 
solar heat, affecting the thermometric mean of any climate, has 
been suggested by M. Poisson. It seems well established by 
observations in the Caves at Paris, and by observations on the 
temperature of the eai-th at Geneva, that the mean air-tempera- 
ture and mean superficial earth-temperature agree at these 
places, though their extremes differ both in amount and epoch. 
If, then, we can by any means find the total effect of the solar 
rays on the superficial earth stratum, we may assume that to 
be the effect due to the direct action of the sun in raising the 
temperature of the place. 

105. M. Poisson has accordingly attempted most ingeniously 
to connect the climateric effect of the solar rays with the indica- 
tions of thermometers sunk to small depths in the ground. From 
the value of the superficial range (whose logarithm is A in the 
expression of art. 93.) one of its factors h may be discovered, 
entering into combination with known or determinable quanti- 
ties, and this quantity /* isf, for any given spot, a number pro- 
portional to the direct climateric effect of the sun's rays A\hich 
may be deduced from it;};. Now let us admit the mathematical 
accuracy of this very intricate investigation, and the admissibility 

* Art. 78. t See art. 94, note. 

J The value of A of art. 93, 94, is the following (in Poisson 's Notation, 

2bh 
page 497) : log —r: — (| x sin ,«* sin y — 2 a Q), 

where cc, y, ft are astronomical constants already mentioned. 
his the constant of art. 94. riote. 
6 is a constant depending on the superficial character of the soil, and also on 

its conductivity. 
D is a function of b, of the specific heat of the soil, and of the longitude of the 

earth's perihelion. 
Q is a very complicated function of the astronomical constants which deter- 
mine the length of the day, and is one of a series of definite integi-als of 
which the succeeding terms are neglected. 
By the combination of two observed values of A -\- B p (art. 93.) b and B are 
eliminated ; the above expression contains only // and known quantities (Poisson, 
p. 499); and the product /t Q expresses (p. 518) the number of degrees by 
which the annual mean temperature of the given place is affected by direct 
solar radiation. 



SUPPLEMENTARY REPORT ON METEOROLOGY. 75 

of the approximations of calculation*, still we find little reason 
to trust implicitly to the results, however ingeniously obtained. 
We have seen (6*9.) that the effective action of solar radiation 
cannot be expressed simply by the quantity of heat which would 
fall on a square foot of the earth's surface were the atmosphere 
removed ; but the absorption is very great even in the clearest 
weather, and therefore (even admitting a uniform distribution 
of vapours over the whole year, so that their opacity need not 
be considered as a function of the time) the quantity of solar 
heat depends on the thickness of the atmosphere traversed, and 
is therefore a function both of the hour angle and of the fraction 
of a year. The integrals, therefore, expressing the discontinu- 
ous quantity of sunshine, are wholly unadapted to the physical 
conditions of the problem. 

106. That h cannot thereby be rightly estimated, will appear 
from this consideration : viz. that the whole effect of sunslnne 
can only be deduced from the annual range at a given depth (or 
at the surface) by the following reasoning. The winter-action 
of the sun may (it is assumed) be compared d. priori with the 
summer-action of the sun, and the excess of the latter action 
determined ; but the Effect due to this Excess being observed 
(viz. the annual range), the effect due to either of the constituent 
actions (summer or winter) may be found, which gives the whole 
climateric effect of the sun at anj- season, and hence its mean 
effect throughout the yearf. Now in applying this principle, 
it is clear that unless the a priori estimate of the sun's relative 
radiation in summer and winter be made on correct principles, 
a knowledge of the difference of effect due to the change of the 
cause will not lead to a correct value of the cause. In point of 
fact, a neglect of the absorption due to obliquity (not to mention 
the enormous excess of cloudy weather in the winter half-year) 
will inevitably lead to an under estimate of the proportion which 
the summer radiation bears to the winter radiation, and (as the 
difference between these effects is the quantity known) the value 

• So involved are these expressions, that the author himself has inadvertently 
made use of two identical values of one quantity, this same h, and quoted the 
coincidence as a proof of the accuracy of the formulae and observations (p. 
503-4). This he admits in the Supplement, page 72. 

t This at least is my understanding of the principles of solving the problem. 
The problem which Fourier has proposed {Mem. de Vlnstitut, v. 167, &c.) is 
a much simpler and also a less important one, viz. to find the quantity of solar 
heat alternately absorbed and emitted by the earth's surface in the course of a 
year, which evidently does not include the permanent or mean heat derived 
from the sun, and which is subject to no annual change, but which would be 
dissipated were the sun extinguished. 



76 REPORT 1840. 

of the constituent effects will also be under estimated, or the 
climateric effect of the sun will come out too small. 

107- Such, indeed, is almost certainly the case. The climateric 
effect of the sun at Paris is estimated from the superficial range 
of temperature (deduced by Poisson from Arago's experiments) 
to be only 24° cent.*. Tiie mean temperature of Paris being 
11° cent., there remains for the temperature which would re- 
main if the direct influence of the sun were removed, — 18° c. 
or + 9° Fahr., a result altogether improbable. Further, the 
thickness of a sheet of ice over the whole globe which would be 
melted by the entire annual action of the sun, would be, accord- 
ing to Poisson, seven or eight metresf, whilst Pouillet supposes 
it four times as great J. 

108. Fourier, in his remarkable Memoir on the Heat of the 
Globe §, had clearly show-n that its superficial temperature 
depends on three causes, which may be kept wholly distinct. 
1. Solar heat. 2. Temperature of space. 3. Internal heat. To 
these M. Poisson lias added Atmospheric Heat, which, however, 
is merely that part of the solar heat absorbed by the atmosphere 
and communicated secondarily to the earth, independent of that 
received by direct radiation. 

109. Since the Report of Prof. Whewellon the Mathematical 
Theory of Heat, to which we refer for what had been written 
on these subjects at that time, several new contributions to 
this interesting branch of science have been made, both theore- 
tically and experimentally ; I allude particularly to the publica- 
tion of Poisson's Theory of Heat, and Pouillet's Memoir before- 
cited. 

1 10. Poisson's Theory of Atmosphkric Heat has met with a 
very just criticism, in almost every part of which I entirely agree, 
at the hands of Prof. Auguste de la Rive, of Geneva. His ob- 
jections are so ably and clearly stated, that so far as they antici- 
pate my own, it may be sufficient briefly to state them, and refer 
to his article || for details. And first, as to the constitution of 
the atmosphere: Poisson^, adopting the reasoning of Fourier**, 
admits that the temperature of any part of tiie atmosphere must 
be determined by the equality of the heat directly received from 
the sun and indirectly from the earth, with that radiated abroad 

* Poisson, p. 518. + Foisson's Supplement, p. 7. 

+ Memoiresur la Chaleur Solaire, p. 9. (See above, art. 78.) 
§ Mhnoires de I'Institut, vii. 569; and Whewell's Report, in British Associa- 
tion, Fifth Report, p. 30. 

11 Bihliotlu'que Universelle,^ov. — Dec., 1835. 

'^ Thiorie, p. 448, &c. ** Alim. de I'Institut. vii. 584, &c. 



SUPPLEMENTARY REPORT ON METEOROLOGY. 77 

in space, and in the adjacent atmospheric strata. Proceeding, 
however, to the mechanical conditions of equilibrium*, he infers 
that the temperature of the exterior part of the atmosphere 
must be prodigiously low, in order that it may have a definite 
termination, which condition of non-elasticity he calls liquefac- 
tion f, a term, the impropriety of which will sufficiently appear 
from the observations of M. de la Rive cited below J. It is quite 
certain that an elastic atmosphere may be considered as rigor- 
ously limited, even wholly irrespective of the diminution of elas- 
ticity due to cold, and this without necessarily inferring an as- 
sent to the molecular constitution, from which Dr. WoUaston 
deduced the limitation as a necessary inference §. Hence, any 
hypothesis of extreme cold required to produce mechanical equi- 
librium in the higher parts of the atmosphere is devoid of sup- 
port. As to the actual extent of the finite atmosphere, this is 
a question on which experiments both direct and indirect leave 
us much in the dark ; nor can the optical phsenomenaof twilight 
be cited with much confidence in such a case, the reflective power 
of rarefied air being a datum on which we want direct evi- 
dence ||. 

111. The effect of the atmosphere upon the temperature of the 
globe, as treated of by M. Poisson, is twofold; namely, /irst, 
the modification of solar heat, which after combination with the 
air both radiates, and communicates heat by contact, to the earth ; 
if the sun were extinguished, this heat would also vanish, al- 

* Theorie, p. 459. 

i Theorie, p. 459, and Supplement, note D. p. 60 ; Traite de Mecanique, 
ii. 612. 

X " Nous ne pouvons admettre que cet etat du fluide soit analogue a I'etat 
liquide, du moins si nous attachons au mot liquidele sens physique dans lequel 
on I'entend communement, et par lequel on designe, par exemple, I'etat au- 
quel une basse temperature et une forte compression amenent la plupart des 
fluides elastiques. Si M. Poisson n'entend par liquide que cet etat des fluides 
dans lequel la force elastique est disparu, ce n'est plus alors qu'une definition 
matheiiiatique qui est bonne taut qu'on ne cherche pas a se vepresenter I'etat 
physique du fluide. Tontefois observons que ce n'est pas ainsi qu'on definit 
les liquidos ; pai-ceque I'etat liquide suppose non seulementl'absence de force 
elastique, mais de plus une attraction moleculaire plus ou moins grande entre 
les particules du fluide, attraction qu'il nous est impossible d'admettre ici." — 
Bib. Univ., Nov. 1835. 

§ Phil. Trans., 1822, p. 89. Abstracts, ii. 160, M. Biot appears to give the 
credit of this remark to M. Poisson ; Comptes Rendus, vi. 395. 

II See on this subject M. Blot's Memoirs ; Comptes Rendus, viii. 91 ; ix. 1 74 ; 
Lamben'sWorks ; Lubbock on Heat and Vapours, 1 840 ; also Poisson, Supplement 
a la Theorie de la Chaleur, note D, where the author investigates the equilibrium 
of the atmosphere under certain conditions, but ends with these words: " il ne 
s'agit danscette note, que d'un simple exemple de calcul, et vraisemblablement, 
les hypotheses que nous avons ftiites pour le faciliter ne sont pas conformes a la 
nature." 



78 REPORT— 1840. 

though for convenience it is distinguished from the dii'ect solar 
heat measured by an actinometer ; secondly, the proper low 
temperature of the higher atmosphere which is communicated 
to the earth by radiation through the inferior strata. M. Pois- 
son contents himself with supposing that these two causes neu- 
tralize one another, or that the latter rather preponderates*, 
for which he assigns, I think, no sufficient reason ; on the con- 
trary, from what we have just stated (110.) of the action of the 
atmosphere, which lets more heat enter than can directly escape, 
we conceive that the heating effect of the atmosphere is essen- 
tially positive. 

112. M. Poisson having thus estimated the direct solar effect 
on the climate of Paris at 24° cent., and the atmospheric in- 
fluence as nothing relatively to the existing temperature, assigns 
the temperature which remains, namely, 11°, the actual mean 
temperature of Paris, diminished by 24°, or— 13° ( = 8'6 Fahr.) 
for the heat of space, or the temperature which our globe would 
take were the sun permanently extinguished. 

113. This result must certainly be considered as a very start- 
ling and improbable one. That the temperature which oin* globe 
would take did the sun not heat at all should be actually higher 
than the mean temperature of many points of its surface exposed 
to the solar rays dnring a great part of the year, and nearly 8f)° 
of Fahr. above a degree of natural cold actually observed f, 
is a paradox to which M. Arago drew attention, and which M. 
Poisson we think did not succeed in rendering plausible];. Fou- 
rier was distinctly of opinion that the temperature of space must 
be lower than the mean of any point of the earth's surface, 
though he admits that local causes might produce a temporary 
depression §. The only explanation, indeed, which it can admit 
of, is that to which M. de la Rive has shown that Poisson's rea- 
soning necessarily leads, viz. that the atmosphere is an inde- 
pendent source of heat \\ (or cold, Avhich is the same thing), a 
conclusion nowhere distinctly admitted by the author. Now 
this conclusion surely will be veiy reluctantly adopted, seeing 
that, even supposing the direct solar influence could be success- 
fully estimated, the remaining temperature must be derived from 
(what is called) the heat of space and the heat of the atmosphere. 
Experiments are, I apprehend, totally wanting which can se- 

• " La pavtie (namely, of the heat not directly received from the sun by any 
part of the earth's surface) provenant de I'atmosphere ne nous est pas connue; 
nous pouvons seulement presumer qu'elle est negative." — Theorle, p. 520. 

\ Viz. — 70° Falir., by Captain Back. 

\ Comptes Rendus (Paris), ii. .575. 

§ Mem. de l' Instil ut, vii. 582. || Bib. Univ., Dec. 1835. 



SUPPLEMENTARY REPORT ON METEOROLOGY. 79 

parate these two united effects ; their relation and absolute in- 
tensities are therefore, we presume, yet unknown ; nor can we 
understand how it is possible that the higher strata of the at- 
mosphere can remain permanently colder than the strata be- 
neath and the sky above them, without admitting a paradox of 
the same kind with a mechanical perpetual motion. 

114. I am aware that M.Pouillet, in his memoir so often cited, 
has been led to the same conclusion with M. Poisson respecting 
the low temperature of the aerial coating of the globe, and has 
actually computed the depression of temperature which might 
exist in various hypothetical cases. Until, however, M. Pouillet 
can exhibit an experiment in which so paradoxical a result is 
actually attained, I am inclined to think that we must consider 
it as at variance with the fundamental laws of heat as at present 
received. M. Pouillet has made many ingenious experiments 
with his instrument designed to measure nocturnal radiation ; 
and (since the cooling effect of the sky may always be assimi- 
lated to that of a hollow sphere having a determinate tempera- 
ture) he has, I believe for the first time, endeavoured to translate 
into numerical language the indications of his instrument by 
actually exposing it to the radiating action of surfaces of low 
temperature, which would have the same effect, whatever be their 
distance, and that effect being known in thermometric degrees 
on his instrument, the equivalent temperature of the vault of 
heaven, or what he calls zenithal temperature, becomes known 
too. All this is very ingenious and clear, and such determina- 
tions of zenithal temperatures will certainly one day be of great 
value. But the difficulty is to separate this temperature into 
that due to the atmosphere, and that due to the temperature of 
space. As already stated, we are not satisfied that such a sepa- 
ration has been, or at present can be effected ; and the great 
variations of the assigned temperatures of space strengthen this 
doubt; forwhilst Fourier and Swanberg make it — 40°c.*,Valz, 
— 45°t, Poisson makes it 13°|, and Pouillet between — 115° 
and- 175° §. 

115. Fourier was the first who distinctly introduced the idea 
of the proper temperature of space, as well as the first who endea- 
voured to assign to it a value. Our ideas about an absolute zero 

* See last Report, p. 203, and Fourier, Mem. de I'Institut, vii. p. 598. The 
grounds on which Fourier's estimate is made, nowhere exactly appear; Her- 
schel considers his published statements unsatisfactory (Geol. Trans. III. 297); 
yet it appears that M. Fourier himself was strongly persuaded of the truth of 
his estimate, which he thought was not erroneous to the amount of 8° or 10° 
cent. (Arago's Eloge de Fourier, p. 55.) 

"t" Mahlmann, p. 14, note. J Theorie, p. 520. 

§ Mimoire sur la Chaleur Solaire, p. 38. 



80 REPORT — 1840. 

of tempcratAU-e, far from getting clearer, are perhaps now more 
unfixed than ever ; and what would be the result of a condition of 
which we can form no very definite physical conception (a body 
placed in an envelope deprived of heat), it is perhaps too bold to 
conjecture. But that the planetary spaces are not exactly in 
this condition, is not improbable. A body (be it a thermometer 
or a planet) placed in space may take a temperature, by contact, 
from a fluid by which it is surrounded, or by radiation from 
distant stars (being shaded from the sun) ; the latter, we under- 
stand to be the meaning usually assigned bj'^ philosophers to the 
term Temperature of Space*. This influence may change from 
age to age, and be variable in different regions of the globe, de- 
pending on their exposure. M. Poisson supposes that the in- 
crease of temperature with depth in the earth indicates the effect 
of an at-one-period-more-intense stellar radiation, and con- 
sequently that it does not necessarily extend beneath a depth 
which the epoch of the oscillations of external influence would 
determine. This is no doubt perfectly unanswerable, as a mat- 
ter of bare possibility ; but it seems hardly worth maintaining 
an opinion which a million of years will scarcely show to be 
feasible or the reversef. 

116. We have formerly stated |, that Fourier had arrived at the 
conclusion that the flux of heat from the interior to the surface 
of the globe did not raise the temperature of the latter above 
jLth of a centigrade degree §, or would melt annually a stratum 
of ice :f\^th of an English inch in thickness ; and in this estimate 
Poisson nearly coincides 1| . The influence of internal heat is 
quite irrespective of any theory as to the state of the nucleus, 
and depends only on the rate of increase as we descend, a cir- 
cumstance which M. de la Rive seems to have overlooked in 
urging his objections against Poisson's theory. We proceed to 
state some important additions which have been made to our 
knowledge of facts respecting the thermometric condition of 
the accessible part of the earth's crust. 

• See an interesting notice by Sir J. F. W. Herscliel, read to the Roj-al 
Astronomical Society, 10 Jan. 1840; Atheneeum, Feb. 1.5; where, as well as 
in a paper in the third voUime of the Geological Transactions, New Series, 
on Astronomical Causes affecting Geological Theories, are some important sug- 
gestions on these intricate subjects. 

f On the subject of the thermometric state of the globe, see a popular article 
by M. Arago {Annuaire, 1834), and the JEIoge of Fourier, by the same author. 
In the Annales de Chimie, a few years since, Libri has given some results as to 
the rate of cooling, and the contraction of the earth's crust, within historic 
times, chiefly with a view to the supposed explanation which it affords of certain 
geological phsenomena. 

X Last Keport, p. 221. § Mem. de I'Institut, vii. 590. 

II TMorie, &c., p. 424. 



SUPPLEMENTARY REPORT OX METEOROLOGY. 81 

117. We have no reason to admit any sensible change in the 
mean temperature of the superficial part of the globe ; at least 
we are rather disposed to attribute the manifest elevation of 
temperature observed during twenty years, in the observations in 
the caverns under the Observatory at Paris, to some permanent 
alteration in the instrument than to a change of temperature of 
the earth, a point which we hope the French astronomers will 
take pains to ascertain. The observations from 1817 to 1835 
being divided into four series, give the following results : — 

ll°-730 11°-801 ll°-857 ll°-950* 

118. The mean of 35 2 observations is 11*834 ; the mean tem- 
perature of the air at Paris is 10*822 f; the difference is to 
be attributed to the increase of terrestrial heat for 28 metres 
of descent. 

119. Observations on borings, and overflowing or Artesian 
wells, have been perhaps more unexceptionable of late years 
than at any former period. We shall give such indications as 
to record the chief facts observed. Amongst the best obser- 
vations are those made by MM. De la Rive and Marcet in a 
boring near Geneva J, under the most unexceptionable circum- 
stances, which agree extremely well in indicating a uniform 
increase of heat at the rate of 1° cent, for 32-55 metres of de- 
scent, or 59 feet for 1° Fahr. The whole depth was 255 metres. 

120. A list of Artesian wells and their temperatures has been 
given by M. Arago, in the Annuaire for 1835 ; and by Pois- 
son, on the same authority, in his Theory of Heat§ ; whence 
he has deduced (from fifteen Artesian wells in France, all above 
20 metres deep) an increase of 1° cent, for 25-46 metres of 
descent (46 feet for 1° Fahr.). There appears in these, as well 
as the Geneva and Paris observations, a remarkable coincidence 
between the superficial ground-temperature and the observed 
air-temperature ||. 

121. From the comparison of a number of observations, M. 
Kupffer^ deduces an increase of 25*37 metres for \.° Reaumur^ 
or 20-30 m. for 1° cent., or 37 feet for 1° Fahr. 

122. A well at Magdeburg gives 1° Reawnur for 100 feet, 
or 44 feet for 1° Fahr.**, according to Professor Magnus, the 
inventor of an improved thermometer for such observations. 

• Poisson, Theorie de la Chaleur, p. 414. \ Ibid, p. 467. 

X Mem. de la Soc. de Phys. de Geneve, torn. vi. § P. 420. 

II It is by no means necessary to infer, however, that this is a general fact. 
Prof. Reich's observations, for example, at Freiberg, indicate an excess of 1° c. 
in the earth-temperature above the air-temperature. Beoh. iiber die Temp, des 
Gesteins, &c., p. 134. 

H Poggendorff, xxxii. 284. ** Ibid., xl. 139. See also xxxviii. 593. 

VOL. IX. 1840. G 



82 REPORT — 1840. 

123. A very deep experimental bore has been sunk at La 
Grenelle, near Paris. The latest report* (Aug. 1839) gives a 
temperature of 27°"5 cent, at a depth of 281 metres, which 
would infer an increase of about 1° cent, for 16^ metres (the su- 
perficial temperature being under 1 1°), a result hardly probablef ; 
and as the depth of the bore then was between 400 and 500 
metres, either the depth of observation has been misstated, or 
the temperature was raised by water flowing from the bottom. 

124. The following are the depths of the most remarkable 

Artesian wells at present known t: — 

'^ ^ French feet. 

La Grenelle, Paris (June 1839) 1436-1 

Neu Salzwerk, near Minden (Sept. 1839) . . . 1434*8 

Temperature of brine, 18°*5 R. 

Nowe Brzesko, Poland (1838) 1403-8 

Cessingen, Luxembourg (April 1839) .... 1646-5 § 

125. Perhaps the most interesting, and certainly the most 
singular observations, on subterranean temperature, are those 
on the frozen soil of Siberia. At Jakouzk, in lat. 62°, where the 
mean temperature is —6° Reaum. =18*5 Fahr. (accompanied 
with such a i-igour of climate, that viercury has been knoivn 
to remain frozen for three consecutive months \\), the heat of 
summer thaws the soil to an extreme depth of only three feet^. 
To search for a permanent spring is a matter of great difficulty. 
A well has been dug to the depth of nearly 400 English feet, 
with the following most remarkable results as to the tempera- 
ture of the ground** : — 

Surface — 6°- Reaumur. 

77 English feet . . . - 5 -5 
119 „ ... .—4-0 

382 „ .... - -5 

* Comptes Rendus (Paris), ix. 218. 

\ Thisi'esult is altogether at variance with that formerly published {Comptes 
Rendus, vi. 505), where it appears that at a depth of 400 metres the tem- 
perature was 23°-5 c, giving an increase of l°c. for .3I"5 metres, in which also 
some other springs near Paris very nearly coincide. A still later observation 
confirms this remark. On the \Hth August, 1840, MM. Arago and Walferdin 
obtained a temperature nf 26°' 43 c. at 505 metres, giving 32'3 metres for 1° c. 
{Coviptes Rendus, 2 Nov., 1840.) 

I PoggendorfF, xlviii. 382. Notices of some other Artesian wells, Pogg., 
xxix. 362. For an account of two Artesian brine springs at Kissengen, see 
my paper in Jameson's Journal, April 1839. 

§ It has lately been stated, that the observations of temperature in this Ar- 
tesian well, at the depths of 1 SO, 230, 280, and 337 metres, give a coincident 
result of 1° c. for 13 metres of descent, or more than twice as rapid an increase 
as that usually observed. (L'lnstitut, 1840, No. 340.) 

II Erman, Comptes Rendus (Paris), vi. 502. 
^ Bischoff, Wdrmelehre, p. 137. 

** Erman, ut sup. See also Von Haer, in Brit. Assoc, Eighth Rep., Sect. p. 96. 



SUPPLEMENTARY REPORT ON METEOROLOGY. 83 

From which it appears that we have a progressive increase of 
temperature in the frozen soil, which, at a depth of about 400 
feet, will give a temperature just freezing. The augmentation 
would appear to be more rapid than usual, or 1° R. for 60 or 
70 English feet. 

126. Of observations in mines we have a most important and 
extensive series by Professor Reich, of Freiberg*, made under 
the most favourable circumstances, and with every assurance 
of their accuracy. They extend to a depth of above 900 feet, 
and the result of the combination of the whole is an increase of 
1" cent, for 41-84 metres, or 1° Fahr. for 76 English feet, with a 
probable error of only 1-3 7th partf. 

127. Professor Phillips found, in the Monkwearmouth coal- 
pit, an increase of 25o Fahr. for 1484 feet of descent, or 1° Fahr. 
for 59-36 English feetj. The same gentleman has given valuable 
instructions for conducting such observations §. 

128. Mr. Fox gives 1° Fahr. for 48 or 50 feet as the results of 
his experiments in Cornwall ||. Mr. Henwood agrees with Mr. 
Fox in finding a difference in the progression of heat in slate 
(killas) and granite, and gives the following summary of his 
experiments *f[ : — 

95 observations in slate 1° F. for 39 feet. 

39 „ granite „ 41-4 

This difference, Mr. Fox thinks, is probably attributable to 
the action of the mechanical structure of the' rocks, in admit- 
ting superficial water**. 

_ * Beobacktungen iiher die Temperatur des Gesteins in verschiedenen Tiefen 
in den Gruben des Sdchsischen ErzgeUrges in den Jahren 1830 bis 1832, von 
*. Reich. 8vo. Freiberg, 1834. 

j" ^•}^'^- X Phil. Mag., Third Series, v. 4.51. 

§ Bnt. Assoc, Sixth Rep., p. 291. || Ibid., Seventh Rep., p. 136, &c. 

1[ Ibid., Seventh Rep., Sections, p. 36. 

** ^t will be seen that these experiments have no analogy in their objects 
with those made at Edinburgh on the influence of the material of the strata 
"P°" J^'^e admission of solar beat, as Dove seems to suppose {Reperturium, 

A most important question, connected with earth-temperature, yet remains 
to be decided. M. Kupffer maintains (see First Report, p. 224), that the super- 
hcial temperature of the earth exceeds that of the air in high latitudes, and 
tails short ot it between the tropics (as was long ago asserted by Von Buch and 
others), and he has described Isogeothermal lines to express this fact. BischoflT 
maintams the contrary {Wdrmelehre, p. 38, &c.), declaring that Kupfler's lines 
coincide with those of Humboldt (Isothermal), and that the warmth of springs 
in high latitudes arises solely from the depth at which they rise (p. 53), and he 
quotes the observations made by Boussingault, one foot h&Xovf the surface (where 
tie linds the temperature constant in tropical regions, and equal to the mean 
air-temperature of the year, Ann. de Chimie, liii. 225), in support of the 
assertion, that at the equator no difference of air- and earth-temperature exists 

G 2 



84 REPORT — 1840. 

129. Most intimately connected with the subject of subter- 
ranean temperature is that of the temperature of springs, which 
connects itself so remarkably with chemical, geological, and 
meteorological considerations. It is impossible not to adopt 
the idea, that the temperature of spring-water depends on the 
depth whence it takes its origin, since we now know, beyond 
any doubt, that up to a certain point at least, the heat of the 
strata increases as we descend ; nor is there the slightest reason 
to suppose that this progression undergoes any considerable 
variation down to the (comparatively) moderate depth at which 
water would boil, however much we may feel the necessity of 
caution in inferring the actual condition of the earth's nucleus. 
The subject is one of so much extent, that we must refer gene- 
rally to the works which specifically treat of it, amongst which 
that of Prof. Bischoff, of Bonn*, is the most important in our 
present point of view. According to him, the temperature of a 
spring is an index simply of the thermal condition of the 
stratum whence it takes its origin, or at least derives its chief 
heat. 

130. A very ingenious application of these principles has been 
made by Prof. Kupffer, and he has illustrated them by an ap- 
plication to observations of the temperature of two springs at 
slightly different elevations, near Edinburgh, made at differ- 
ent seasons of the yearf. By observing the annual range of 
temperature of the spring, its depth is known by Fourier's 
formula, the conductivity of the soil being assumed from 
Leslie's experiments. The retardation of epochs is also an 
index of the depth. Now the actual difference of level of the 
points of exit of the two springs being given, the difference of 
temperature due to height above the sea is known. The actual 

Very contrary results on the latter point, derived from springs, appear in M. 
Arago's report on a recent French expedition, under command of Capt. Du- 
Petit-Thouars {Annuaire, 1840, p. 296), from which the ground would seem to 
be sometimes 4° cent, colder than the air. — Nov. 1840. 

* Die Wdrmelehre des Innern misers Erdkorpers, 8vo. Leipzig, 1 837. 
Some part of this work has been translated in the Edinburgh Philosophical 
Journal. It consists of four parts, containing 27 chapters, and is full of re- 
search and important information. 

t These observations, published anonymously in Prof. Jameson's Journal in 
1828, were made by me. I have only lately found that they have been sub- 
jected to an ingenious and searching analysis, first by Kamtz {Meteorologie, 
ii. 190) afterwards by Kupffer (Poggendorff's ylnnalen, xxxii. 280), and 
made to yield results which, in making them, I could not have contemplated. 
This is one instance out of many, for the encouragement of young observers, 
showing that observations conducted on system, carefully and perseveringly 
made, and complete so far as they go, may afterwards prove of unexpected 
importance. 



SUPPLEMENTARY REPORT ON METEOROLOGV. 85 

difference of observed temperatures is not, however, the same, 
because the one spring rose from a greater depth than the 
other. The variation due to this cause then becomes apparent ; 
and the difference of depth from which they rise being known, 
the rate of increase is found by M. Kupffer to be 1° Fahr. for 41 
English feet ; a process which must be admitted, at all events, 
to be extremely ingenious. He has treated some of Wahlen- 
berg's observations in a similar way*. 

131. On the subject of hot-spi-ings, or those which have a 
temperature notably higher than that of the air, (though, as 
Bischoff has well remarked, there is an insensible gradation,) 
we cannot now enter; and this is the less to be regretted, as 
Dr. Daubeny has already presented an ample report to the 
British Association on the subjectf. M. Arago has published 
some valuable remarks on the same subject, especially on the 
curious phaenomena of the springs of Aix in Provence J. With 
a view to direct the attention of naturalists to the secular and 
annual changes of temperature in hot-springs, I have made 
some very detailed investigations on this subject, which I have 
published, as far as relates to those in the Pyrenees §. The 
central heat theory would require these to be insensible, as 
indeed they appear to be in the best known instances. 

II. — Atmospheric Pressure. 
A. JBaromeiers\\. 

132. The standard barometer of the Royal Society of London 
has two tubes, one of flint, the other of crown glass, adapted to 
a common cistern, with a view, it is believed, of ascertaining 
whether any change in the capillary action occurs, depending 
on the nature of the tube. The scale, according to Dr. Prout's 
ingenious construction, is itself moveable, its zero coinciding 
with a fine agate point, which terminates it, and which may be 
brought into the nicest contact with the mercurial surface in 

* In Prof. K&mtz's Lehrbuch der Mefeorologie, ii. 186, &c., is much valu- 
able information on the subject of sprinss; also in Dove's Repertorium, 
iii. 310. 

t British Association, Sixth Report, pp. 1 — 95. 

X Jnnuaire die Bureau des Longitudes, 1836, p. 265 ; see also M. Valz's com- 
munication, Comptes Rendus, vol. x. 

§ Phil. Trans. 1836. On the subject of hot springs, Osaun's work in 2 vols. 
8vo. {Europas Heilquellen, Berlin, 1829), may be consulted in German, Ali- 
bert's in French, and Gairdner's in English ; but the temperature observations 
seldom afford more than a rude approximation to the truth. 

II See last Report, p. 225. Mahlmann, p. 77. 



86 REPORT — 1840. 

the cistern ; the vernier has a proper motion upon the scale, 
in order to read off the height*. 

133. M. Kupffer has proposed a stationary harometer, in 
which a siphon-tube stands alone, and quite detached from a 
graduated column, along which a micrometer travels, and reads 
off the diffei'ences of elevation of the two extremities of the 
mercury f. M. Breithaupt has also proposed a plan somewhat 
similar J. It may very safely be affirmed, that the mechanical 
act of reading off the length of the column is already accom- 
plished with more accuracy than the otherwise imperfect nature 
of the instrument requires. 

134. Mr. Daniell reconmiends Newman's portable barome- 
ters, with correction for the capacity of the cistern, and such 
have been supplied to the Antarctic expedition §. Mr. Newman 
has adapted an ingenious cast-iron cistern to his instrument, 
which consists of two parts, one of which contains the super- 
fluous mercury during carriage, the other being always full ||. 

135. M. Bunten, of Paris, a most ingenious and excellent artist, 
has made a great improvement on Gay-Lussac's portable siphon- 
barometer, in which a chamber is left in the principal tube, in 
which any air which may have accidentally left the bend of the 
siphon is inevitably lodged, and may be expelled at leisure 
without injury to the vacuum. M. Bunten constructs these 
instruments himself with peculiar skill, and provides them with 
excellent portable wooden cases. The same artist has recently 
contrived a very ingenious, elegant, and simple cistern-baro- 
meter, with the graduation on the glass, and which can be made 
at so moderate a price as ought to supersede the rude instru- 
ments commonly purchased at twice the cost^. 

136. Greiner, of Berlin, a most excellent manufacturer of 
meteorological instruments of the most delicate kind, has con- 
structed a siphon- barometer, with the material advantage of 
confining the superfluous mercury (which by frequent shaking 
becomes oxidated), and yet in such a way, that the expansion 
by heat cannot possibly endanger the instrument**. His baro- 
meter, more cumbrous and more expensive than Bunten 's, is 
well adapted for nice observations, to be pursued for some time 
at a fixed station, whither the instrument has first to be con- 
veyed. 

* See Mr. Baily's description, Phil. M^g., Third Series, xii. 204. 
t Poggondoi-ff, xxvi. 446. % Ibid., xxxiv. 30. 

§ Royal Society, Instructions, p. 56. || Brit. Assoc, 3rd Report, p. 417. 

II The defect of this instrument in its present form, is the difficulty of access 
of the air to the cistern. 

** There is a descriptive pamphlet published at Berlin in 1 835. 



SUPPLEMENTARY REPORT ON METEOROLOGY. 87 

137. Mr. Harris, of Plymouth, has had the merit of exe- 
cuting, for the first time, perhaps, with accuracy, a wheel, or 
circular index-barometer, a matter of very great importance as 
well as difficulty, because it enables unlearned persons to read 
off the height without the aid of a vernier ; and in fact to this 
we owe the most valuable and unique series of hourly barome- 
trical observations, to which we shall presently refer*. 

138. Prof. Stevelly, of Belfast, has proposed a self- registering 
barometer, on the principle of causing a moveable cistern con- 
taining mercury to rise or fall by the weight of the fluid dis- 
placed from a fixed barometer tube immersed in it. The tube 
here may evidently be opaque, as of ironf. 

139. A water-barometer has been constructed and observed 
in the Royal Society's Apartments (London). Some elaborate 
comparisons of its indications with standard instruments will 
be found in Mr. Hudson's paper J. 

140. On the still-agitated subject of capillarity, as affecting 
barometric readings, I refer to some recent essays of Bessel, 
Dulong, and Bohnenberger §. 

141 . Of barometers acting on principles different from that of a 
simple column of mercury, the so-called (not very appropriately) 
differential barometer of Auguste, as improved by Kopp||, is 
the most ingenious. Its principle, so far as it can be concisely 
stated without a figure, is this : if air of any density whatever 
be compressed into a given fraction, say fths of its natural bulk, 
it will sustain a pressure equal to the atmospheric pressure, and 
a certain fraction more, depending on the fraction denoting the 
compression (in the supposed case its elasticity would be 
balanced by the atmospheric pressure, and ^rd more). If, then, 
this fraction of excess of pressure is known by experiment, the 
whole pressure is inferred from a knowledge of the construction 
of the instrument. Thus, instead of a column of 30 inches of 
mercury being required, one of 15, 10, or any other number 
may be used and multiplied by the constant factor. In Kopp's 
instrument, the experiment is very simply and neatly made. A 
glass chamber communicates freely with a vertical tube, which 
is open to the air until mercury forced in from beneath cuts off 
the communication : the pressure by which the mercury is in- 
troduced being continued, the air in the chamber is condensed, 
and the mercury rises in the vertical tube, so that its pressure, 
together with that of the atmosphere, may balance the elas- 
ticity of the air. The compression is continued until the air is 

* British Association, Third Report, p. 414. 

t Transactions of the Royal Irish Academy, 1836. 

X Phil. Trans. 1832. § Poggendorff, xxvi. 451. 

II Poggendorfi; xl. 62. 



88 REPORT — 1840. 

observed to be condensed to a known fraction of its bulk, when 
the length of the column of mercury is also a known fraction of 
the total barometric column. I brought one of these instruments 
to this country two years ago, but I have not yet made trial of it. 

142. Mr. Cooper has proposed a barometer acting by the 
elasticity of the air in a floating vessel regulated by weights, 
which constantly immerse it to the same depth*. The author 
considers it capable of showing a difference of elevation of three 
or four feet. It is intended that the apparatus should in every 
case be employed at a constant temperature of 75°, to which it 
is artificially brought : I conceive that tliis process is attended 
with inevitable disadvantages. 

143. Sir John Robison has proposed to use tubes or long phials 
containing air, immersed in water at the top of a hill, instead 
of an air barometer or sympiezometer. The portion which be- 
comes filled with water, when re-examined, would indicate the 
previous rarefaction of the airf. In this and everj-^ similar case 
the temperature of the included air is a matter of great uncer- 
tainty, and prevents the possibility (as contemplated) of trust- 
ing such instruments to inexperienced assistants. 

B. Mean Height of the Barometer. 

144. Several considerations would lead us to tlie inference, 
that the mean pressure of the atmosphere at the level of the sea 
should vary with the latitude ; but it is to experiment alone 
that we can look for any indication of a law. Humboldt ap- 
pears first to have remarked, that the height of the barometer 
is lower at the equator than in temperate latitudes;}:; and, 
excepting this fact, little more has been known until the late 
excellent researches of Schouw§, though the partial observa- 
tions of occasional navigators indicate this fact, as well as a very 
considerable depression of the barometer towards the pole||. 

145. M. Schouw's statement is the following: — 

Mean pressure at Level 
Sea, in French Lines. 
Lat. 0° to 15" high temp, with a rainy season 337 — 7 
„ 15 — 30 very dry; rains rarely . . . 338 — 9 

„ 30 — 45 temperate 339 — 7'5 

„ 45 — 65 cold and rainy 337"5— 3 

* Philosophical Transactions, 1839, p. 425. 

f British Association, Eighth Report, Sections, p. 37. Brunner has de- 
scribed an air-barometer, Poggendorff, xxxiv. 30. 

X Tableau Physique, p. 89, quoted by Kamtz. 

§ Annales de Chimie, tome liii. (1833). See also Poggendorff, xxvi. 395. 

II See the authorities cited in Plumboldt's Note to Arago, Comptes Rendus, 
ii. 570. Some valuable comparisons of barometers at different northern observa- 
tories are to be found in a late number of the Comptes Rendus (1840. 2me 
Semestre). 



SUPPLEMBNTARV REPORT ON METEOROLOGY, 89 

The maximum appears then to be about the 45th degree, and it 
diminishes on either hand. 

146. The equatorial depression, and the maximum near the 
40th degree of latitude, is indicated not only by Xh^Jixed annual 
observations given in Schouw's paper, but also by progressive 
observations made on board ship by Capt. Beechey*, Sir J. 
Herschelf, Sir E. Ryan f, and Mr. MacHardyt ; the latter are 
important, as showing that the same distribution prevails in the 
southern hemisphere. Mr. MacHardy's observations in southern 



itudes give 




Between 0" and 5° S. . 


. . 29-821 Eng. inches 


55 5 ,, 15 . . 


. . 29-802 „ 


,5 15 „ 25 . . 


. . 29-960 „ 


„ 25 „ 35 . . , 


, . 30-085 



147. Prof. Poggendorff, of Berlin, has very justly remarked ;{:, 
that the question of the actual pressure of the air at any point of 
tbe earth's surface, supposes that that pressure is measured upon 
a constant scale of force ; but owing to the variation of the force 
of gravity, the weight of a given length of the mercurial column 
is not constant, and the effect of attending to this correction is 
to exaggerate the depression at the equator, and diminish some- 
what (but not annihilate) that in the arctic regions. Such a 
corrected table, deduced from Schouw's, will be found in the 
Comptes Rendus and in Poggendorff's Journal. The propriety 
of the correction will be evident (as M. Poggendorff observes), 
if we recollect that the elasticity of air, and the boiling point 
of water, may be used, as well, as the counterpoise of mercury, 
for indicating the atmospheric pressure. 

148. The height of the barometer, at least in temperate regions, 
varies with the season of the year. At Paris and Strasburg it 
appears to attain one maximum in summer and another in 
winter. M. Kamtz attributes the summer maximum, with great 
probability, to the pressure of vapour §: when this is allowed 
for, we have a maximum in February and a minimum in August 
or September. The prevalence of particular winds (as we shall 
see) causes temporary elevations of the barometer in particular 
parts of the earth's surface, which may lead, and have led, to 
very erroneous conclusions. 

149. There seems, however, on the whole, no reason to doubt 
the existence of such atmospheric valleys as were adverted to in 
the former report ||. 

* Comptes Rendus, ii. 572. 

+ Second Report of the Meteorological Committee of the Soiitli African 
Institution, p. 2 (for which I am indebted to Sir J. Herschel). 
X Annalen der Physik, xxxvii. 468. 
§ Lchrburk, ii. 297. il P. 228. 



90 REPORT — 1840. 

150. There is no instrumental result to be received at all times 
with more doubt than the absolute height of the barometer. I 
have had occasion to compare many which have the character 
of being standard instruments, and have found the most serious 
inconsistencies. There are few points at which the mean press- 
ure of the atmosphere can be said to be accurately known. 
Even at Paris there is some little doubt* ; when reduced to 
the level of the sea, it appears to be 760-85 millimetresf. From 
seventeen years of very careful observations at Marseilles, it is 
761-61 at 0°, and at the level of the sea J, clearly indicating 
that Paris lies considerably to the N. of the maximum pressure 
zone. It may be doubted whether we possess in this country 
any satisfactory evidence of the mean height of the barometer 
at the level of the sea§. 

C. Barometric Oscillations \\. 

151. The investigation, by Mr. Snow Harris, of the diurnal 
atmospheric tide by means of hourly observations, continued at 
Plymouth night and day for three years ^, has led to a very 
satisfactory determination both of the epoch and amount. Ac- 
cording to him, the maxima occur at 9§^ a.m., and at 10^ p.m., 
the minima at 4^^ a.m., and 3^^ p.m.; and the measures ap- 
pear to be the following (approximately) : — 

Rise from 4 a.m. to 10 a.m. . . -014 inch 

Fall „ 10 A.M. to 3 p.m. . . -017 „ 

Rise „ 3 p.m. to 10 p.m. . . -021 „ 

Fall „ 10 P.M. to 4 A.M. . . -018 „ 

The maximum oscillation here appears to be between 3 p.m. 

and 10 P.M., and amounts to 0*53 millimetres. My formula** 

gives 0-60. Mr. Harris deduces 29-800 for the mean pressure 

60 feet above the level of the sea, which agrees nearly with the 

observations at Somerset House ; but there is some material 

discrepancy in the observations of mea)i height for different 

years. 

* M. Bouvard gives 755'99mm. reduced to 0° c. from eleven years' obser- 
vation at Paris ; M. Arago, 755-43 mm. from nine years' observation. 

t Arao-o. :!: Kindly communicated to me by M. V'alz, of Marseilles. 

§ The Royal Society Observations since Nov. 1837 (see Phil. Mag., xii. 
204), may one day afford this, but the period is as yet rather too short. 
I Last Report, p. 229. Mahlmann, p. 89. 

^ The results were partly communicated to the British Association in 1839 
(see Athenceum, lith Sept.). The following results, which are corrected for 
iemperature and embrace three years, were communicated to me by Mr. Harris 
himself. The agreement of the three years is very satisfactory, so far as the 
form of the curves is concerned. See also British Association, Eighth Report, 

P- 22. 

** Edinburgh Transactions, vol. xii. 



SUPPLEMENTARY REPORT ON METEOROLOGY. 91 

152. Mr. Caldecott, astronomer to the Rajah of Travancore, 
has obligingly communicated to me the results of his observa- 
tions in 80° 30' N. lat., where he finds the oscillation from 10 a.m. 
to 4 P.M. to be '109 English inches = 2*77 millimetres, whilst 
my formula gives 2-57. There appears to be some anomaly at 
the Cape of Good Hope, if the reductions with which Sir John 
Herschel has furnished me represent correctly the series of 
observations made at the Royal Observatory there. From 
58 months' observations (lat. 33° 56' S.), the oscillation is 
•025 mm. = 0*64 mm. The formula would give 1*42 mm., or 
more than twice as much ; a difference altogether improbable, 
or else indicating some remarkable local anomaly. 

153. Colonel Sykes* finds the maximum atmospheric tide in 
the East Indies (mean lat. 18i°, mean elevation 1800 feet), to 
be between 9-10 a.m. and 4-5 p.m., and to amount to '107 inch 
= 2*72 mm. by four years' observations. The formula gives 
2"28 mm. Colonel Sykes finds the hours to be unmodified by 
elevation, and to be the same as in Europe and America. He 
has also shown such enormous irregularities in the results from 
different parts of India, and even in the same place at different 
times, as do not so much militate against any particular for- 
mula, as they show the impossibility of any one formula 
embracing such discordant conclusions f. Colonel Sykes has 
shown that the supposed interruption of the atmospheric tide 
during the prevalence of the monsoon has no existence^. 

154. Prof. Kamtz§ has made some interesting observations 
on the variation of the atmosphei'ic tide with height|| in Switzer- 
land, on the summits of the Faulhorn and Rigi, compared with 
Zurich and Geneva. The hours are nearly the same in all 
cases, 4 a.m., 10 a.m., 3 p.m., 9 p.m. 

French Lines. 
The mean oscillation at Zurich and Geneva . 0*398 
„ Faulhorn . . . , 0-119 

* Philosophical Transactions, 1835. f Ibid., p. 176. 

X An account has been published (Proceedings of the Royal Society, May 
21st, 1840), since this report was written, of valuable Observations on the 
Barometei-, by Capt. Thomas, at Alten, in Finn-marken, in lat. 70° • from 
which it clearly appears that the barometric oscillation is there negative, as my 
formula would indicate that it ought to be. I am bound to apply to the 
" Report" on Capt. Thomas's Observations piiblished as above, the remark 
which I have made upon Colonel Sykes's paper, in the text, viz. that it is 
scarcely philosophical to expect that any formula should coincide more nearly 
with observations, than one year's observations do with another. 

§ Poggendorff, xxvii. 345. See also Gautier on the Annual and Diurnal 
Variations of the Atmospheric Tide. Bibl. Univ., N. S., xxiv. 124. 

II See former Report, p. 232, and my paper in Edinburgh Transactions, 
vol. xii. 



92 REPORT — 1840. 

Another series gives — 

Mean oscillation at Zurich 0-286 

„ Rigi 0-105 

The two results agree very closely in assigning a value of the 
oscillation depending on the absolute pressure. M. Kamtz 
thinks that the diminution with height is as the diminished 
pressure, and may be expressed by s^^th of the change of 
pressure. Thus, at the equator, the oscillation (according to 
him) would cease at a height where the barometer falls to 115 
lines, and afterwards, no doubt, would become negative, as I 
have formerly shown. The observations cited by Col. Sykes* 
confirm the general principle. 

155. The cause of the diminution of the diurnal tide with 
height is no doubt this : — that the great vertical depth of air 
wh^ch exists between Geneva and the Great St. Bernard, for 
example, becoming heated by the action of the sun commencing 
at the earth's surface, a portion of air is raised above the upper 
station in the afternoon, which in the morning was heloiu it ; 
consequently this produces a diurnal tide in the higher regions, 
which has its maximum after the hottest part of the day, and 
which therefore counteracts the true diurnal tide. 

156. On the subject of the lunar influence on the barometer, 
we may refer, in the first place, to the popular article by M. 
Arago, in the Annuuire for 1833 f; who gives the results of 
Flaugergues, mentioned in our last report |, which give a de- 
cided maximum at the last quarter, with which the observations 
of MM. Boussingault and Rivero, at Santa Fe de Bogota, 
agree. According to a late and complete reduction of the 
Paris observations by M. Eugene Bouvard§, we have a first 
maximum on the 8th day of the moon, and a second or j)ri7i- 
cipal one on the 22nd day ; the j)rincipal minitnum on the 
13th, and a second on the 27th day. Here, therefore, we have, 
as above, a decided maximum about the last quarter. The 
oscillation is 1-78 mm. Mr. Snow Harris has arrived at the 
same result as respects the principal maximum |i, which may 
probably be considered as established. We shall return to this 
subject in treating of the fall of rain, and dependence of weather 
on the lunar phases. 

D. Barometric Variation with Height^. 

157. I will add a few observations on this subject, especially 

• Phil. Trans. 1835, p. 176. t P- 173. | P. 234, 

§ Correspondance de V Observatoire de Bruxelles, torn, viii, 

II AthenEeum, Sept. 14th, 1839. 

^ Last Report, p. 236. Mahlmann, p. 119. 



SUPPLEMENTARY REPORT ON METEOROLOGY. 93 

in correction or addition to those contained in my former 
report. 

158. M. Bessel has given an Essay on the Theory of Baro- 
metrical Measurements*. 

159. The important question of determining levels by obser- 
vations of distant barometers, is materially affected by the now- 
admitted difference of mean barometric pressures at different 
localities ; and it also appears that, unless these observations 
are steadily continued for considerable periods, they must be 
liable to serious errors. Thus M. Galle (the assistant astrono- 
mer at Berlin) has pointed out, in two interesting communica- 
tions f, that in certain situations enormous errors of barometric 
measurements arise at certain seasons, which he ascribes to the 
influence of local winds. It is very plain, that if, from any 
cause, the monthly variation of mean pressure of which we have 
already spoken, follow one course at one station and another at 
a second, the height deduced from any barometric formula will 
also depend upon the season. This M. Galle has found to be 
most remarkably the case between Katherinenburg and St. 
Petersburg. The calculated difference of height varies with the 
season, having a maximum in summer and minimum in winter; 
it depends, in fact, on the Difference of Temperature of the two 
stations. The height is greatest when the difference of tempe- 
rature is least ; and wheji the difference of temperature changes 
its usual sign, the height becomes greatly exaggerated. Thus 
we have the following analogies : — 

DifF. Temp. Katherinenburg above 





Reaum. 


St. Petersburg, in Toises 


from 


— 2« to 0° 


141 




2 


103 




2 4 


93 




6 7 


82 



The differences of temperature again depend immediately on the 
prevailing wind, and therefore on the season. Such an anomaly 
is not observed between Kasan and KatharinenburgJ. 

160. This anomaly is both important as a physical fact and in 
its consequences. The vast continental regions of Russia sustain 
aerial columns, which do not make hydrostatic equilibrium with 
one another. It affords a fresh reason for re-inyestigating the 
much-agitated question of the level of the Caspian Sea§, which 
may now probably be considered as set at rest by the results of 

• Schumacher's Astr. Nachr., No. 279. Poggendorff, xxxvi. 187. 

t Poggendorff, xlviii. 58. 379. 

X Humboldt, Ehrenberg, and Rose's Reise, i. 277, quoted by Galle. 

§ See an elaborate paper by Lenz on this subject, Poggendorff, xxvi. 353. 



94 REPORT — 1840. 

the last Russian expedition, by whom the space between the 
sea of Asov (communicating through the Black Sea and Medi- 
terranean with the ocean), has been accurately levelled, and the 
depression of the Caspian found to be real, but amounting to 
only 81 '5 English feet*, instead of 334 feet, as formerly sup- 
posed f. But what is interesting is, that the barometi*ical 
observations made with the utmost care, and at multiplied 
intermediate stations (one German mile apart), confirm the 
older I'esults obtained by the same means. The very same 
kind of anomaly as observed between Katheriiienburg and St. 
Petersburg, occurs here, and even gives to the elevation of the 
Sea of Asov a negative sign at certain seasons. The Sea of 
Asov, though further south and lower than the Caspian, has a 
climate 30° Fahr. colder in the middle of January;]:. 

161. There seems to be very little doubt that the Dead Sea 
lies also below the level of the ocean. The very discordant, 
but almost simultaneous results, obtained by different travel- 
lers §, lead us to admit the fact as pi'obable, and even to con- 
jecture that the depression may be considerable. 

162. M. Kamtz|| has given some very useful results as to 
variations of computed height depending on the hour of the 
day, which acts much in the way in which the season of the 
year affects barometi-ical measurements. The maximum cal- 
culated height occurs at noon, or soon after; the minimum, about 
4 a.m. The effect is far greater than tlie atmospheric tide would 
produce, amounting to 21—27 toises upon 1100 (the difference 
of height of the Faulhorn and Zurich, or Geneva), and to 13 
upon 700 (Rigi and Zurich). Hence it appears that Ramond's 
rule of employing the noon observations for deducing heights 
is not in this respect exactly, 

163. We do not of course propose to give any results of baro- 
metrical measurements. The temperature of boiling water is 
not unfrequently employed, but seldom with sufl&cient instru- 
ments. It has several practical difficulties ; amongst others, 
that of obtaining sufficient heat at great elevations, and in ex- 
posed situations, to cause water to boil. M. Hugi, of Soleure, 
in his enterprising Alpine excursions**, has used the boiling 
point of alcohol with good effect. It may seem surprising that 
this should be tolerably constant, but such I have assured 

* Poggendorff, 1840, and Edin. Phil. Journal, July 1840. 
t First Report, p. 239. % See Galle, ut sup. 

§ Edinburgh Philosophical Journal, 1840. 
II Poggendorff, xxvii. 345, and Dove's Repertorium, vol. iii. 
if On the influence of winds on barometrical measurements, see Brandes, 
Beitriige, p. 216. 

** Naturhistorische Alpenreise. 8vo. Solothurn, 1830. 



SUPPLEMENTARY REPORT ON METEOROLOGY. 95 

myself by experiment to be the fact. Hugi states (what is very 
conceivable), that the boiling point of water anticipates the 
barometric indications by some hours ; but he states (what is 
more difficult to understand), that the boiling point of alcohol 
harmonizes with the latter*. 

III. HuMIDITVf. 

A. Hygrometers. 

164. No new hygrometer has been introduced of late years, 
so far as I am aware, at least no important novelty, but very 
considerable progress has been made in the right interpretation 
of results J. 

165. By far the completest historical treatise which I have seen 
on hygrometry and hygrometers, is a learned thesis by Suer- 
man (different from the one already cited), entitled " Commen- 
tatio de dejiniendd quantitate Vaporis Aquei in Atmospherd," 
&c. §, which also contains good figures, and many pertinent 
original criticisms. 

166. As hygrometry essentially turns upon a right knowledge 
of the relations of heat and moisture, we may first observe, that 
a considerable number of attempts have been made (without new 
experiments) to express, by some simple formula, the relation 
between the temperature and pressure of vapour. The only 
experiments of any consequence that I am acquainted with are 
those of the Fi*anklin Institute (America), conducted under the 
superintendence of Prof. Bache||. They do not much surpass 
10 atmospheres, and even there the difference is 6° Fahr. be- 
tween them and M. Dulong's results, a difference which does not 
seem to be satisfactorily accounted for. M. Dulong's formula 
represents observations above 1 or 2 atmospheres better than 
those below ; and there is reason to think that, whether from the 
mode of conducting the experiments, or some other cause, there 
is some solution of continuity in the law which expresses the 
relation of density and pressure somewhere near the point arbi- 
trarily called the boiling pointy. 

• Naturhistorische Alpenreise, p. 16, 

f See last Report, p. 239, and Mahlmann, p. 129. 

X " Jam vero laetior campus arridet qiio recentiorum experimenta exponenda 
veniunt, qui, de vaporis natura loiige certiores, multa simpliciorem tutioremque 
viam quam prsecedentes physici, ingredi potuerunt." — Suerman, Commentatio, 
§45. 

§ 4to. Lugd. Bat. 1831, p. 123. For this, too, I was indebted to the late 
Prof. Moll. 

II Report on the Explosions of Steam Boilers. Philadelphia, 1836, p. 76. 

1[ The formula which the American Committee adopt to represent their re- 
sults is (for Force corresponding to Degrees of Fahrenheit) e = (-00333 < + 1)". 



96 REPORT— 1840. 

167. Spasky* has taken the trouble to ascertain whether the 
constants in Dulong's formula (viz. the factor of t and the ex- 
ponent), might not be altered so as to represent the observations 
better, but he has obtained a very insignificant change. 

168. Egenf, writing on the same subject, criticises the different 
formula, and gives one expressing the temperature in a series 
of successive powers of logarithms of the force or pressure. 

169. Biott, Schmeddink§, and Roche ||, have all written on the 
same subject recently, and proposed new formulae. Mr. Russell 
has proposed to adopt a modification of Dalton's scale of tem- 
perature, by which the elasticities may follow an accurately 
geometrical progression^. Mr. Lubbock** has deduced, from 
theoretical considerations, a formula sufficiently simple, and 
which represents, with extraordinary fidelity, the observations 
of the Commission of the Institute ; less accurately those of 
Southern below 212°. 

170. I mention these results as generally connected with the 
subject; the actual range of hygrometric observations requires 
such a formula to be used as shall best represent the elasticities 
under 212°. 

171. The formulae in use are (1.) that derived from the obser- 
vations of Dalton and Ure ; (2.) that deduced by Kamtz from his 
own observations tt ; (-^O the table calculated by Ivory's formula, 
founded on Ure's experiments 5 it is that given in Uie second 
edition of Daniell's Meteorological Essays, and adopted in the 
Royal Society's Instructions for the Antarctic expedition. Of 
these, Dalton's has best stood the test of time. Kamtz's is 
recommended by Kupffer^tj hut is condemned by Egen§§, 
Lloyd II II, and Apjohn. In the first place, let us turn for a 
moment to the data of the problem. 

172. The dew-point being obtained by the method of Dalton, 
or that of Daniell, the quantity of vapour in the air, and the 
ratio of the contained vapour to what might be contained in 

* Poggendorff, xxx. 331. Instead of e = (1 + 0-7153 <)^ he finds 
(1 -|- 719 ;)<-'987 for the elastic force, t being in cent, degrees. 

+ Pogg. xxvii. 9. X L'Jnstitut, No. 26, p. 222. Fogg. xxxi. 42. 

§ Pogg. xxvii. 40. II Silliman's Journal, xxviii. 363. 

% Proceedings, Royal Society of Edinburgh, vol. i. p. 227. 

** On the Heat of Vapours, p. 7. Lond. 1840. 

tt M. Kamtz's first work on the subject was published at Halle in 1826. In 
the first volume of his Meteorology, p. 289, he has given an account of 
original experiments on which his foi-mula is founded, which appears to differ 
very sensibly from the results in common use. This formula has had its con- 
stants more lately modified, as appears by M. Kupffer's citation of it. See 
below. 

XX Bulletin de I' Acad, de Si. Petershourg, tom. vi. No. 22. 

§§ Pogg- xxvii. 25. II II Proceedings, Royal Irish .Vcademy, 1810. 



SUPPLEMENTARY REPORT ON METEOROLOCy. 9^ 

air under the circumstances* (which is the true expression for 
dampness), is at once obtainable from a table which shows the 
maximum force of vapour for each degree, and the number of 
grains in one cubic foot of space. But unfortunately tlie ex- 
periment is always a troublesome, sometimes an impracticable, 
and sometimes a fallacious one. Mr. Harcourtf has pointed out 
various mechanical circumstances which affect the appearance 
of a film of dew. To reduce a hygrometric observation to an 
observation simply, and not to an experiment, is the object of 
the moist-bulb problem, in which the refrigeration of a wetted 
surface becomes the index of the dryness. The theory is more 
troublesome, but the observation has every requisite of sim- 
plicity and consistency t- 

173. The moist-bulb problem was especially pointed out as 
one deserving careful solution in the recommendations of the first 
meeting of the British Association at York§, and they have 
been responded to in more than one quarter, so that we may 
now consider the moist-bulb problem as practically solved. 

174. Even at that time the solution had taken a simple and 
exact form in Germany, and for the labours of Auguste||, 
Bohnenberger^ and Kamtz**, the British Association can- 
not probably claim any merit. The works of the two former 
are, I am sorry to say, still as unknown to me (by actual in- 
spection), as when I wrote my former report. 

175. A thermometer having a thin film of water surrounding 
it will take a temperature depending on the following circum- 
stances : — The air in contact (whether it move quickly or slowly) 
gives to the film of water, which is converted into vapour suf- 
ficient in quantity to saturate the space which the air occupies, 
just enough of heat to vaporize that water, and the reduction 
of temperature will be accordingly. Thus, if the air (or space) 
be very dry, it will take up much vapour, but that vapour must 
have combined with much heat in order to change its state from 
water, and the temperature of the air in the (now) saturated 

* When we speak of vapour contained in air, of course we are not to be 
understood to infer any combination between them. 

t Phil. Mag., .3rd Series, vii. 409, and British Association, Fifth Report, 
Sections, p. 54. 

X This method was the invention of Dr. Hutton, of Edinburgh, which 
M. KupfFerhas erroneously attributed to Auguste (Instructions, &c., p. 32), and 
Mr. Prinsep to Leslie (Journal of Asiatic Society of Bengal, 1836, p. 399.). 

§ Original edition, p. 49. These recommendations were drawn up by the 
author of the present report. 

II Uber die Fortschritte der Hygrometrie in der neuesten Zeit. Berlin 
1830. 

^ In the second volume of the Tubingen Nat. Hist. Society's Memoirs. 

** Lehrhuch der Meteorologie, i. 
VOL. IX. 1840. H 



98 REPORT— 1810. 

space is lowered accordingly. Further, it will be more lo^rered 
if the air be rare, or the barometer low, because the air yields 
less heat. All these circumstances may be taken into account, 
and the elasticity of vapour existing in the air may yet be ex- 
pressed by the following simple formula* : — 

e" = fe' - m {t - t') ^^-=-^' 

where t and t' are the readings of a dri/ and a luetted ther- 
mometer ; 

e' the maximum elasticity of vapour corresponding to V ; 
c" „ „ „ to the 

dew-point ; 
b the observed height of the barometer ; 
B a standard barometric pressure (as 30 inches). 
The concluding factor is usually small, and except at great 
heights may be neglected. 

176. Whene", the elasticity corresponding to the dew-point, is 
found, the quantity of vapour existing in the atmosphere is known. 
177- The chief value of a dew-point instrument is to enable 
us to determine directly the value of w?, which the direct experi- 
ments on the specific heat of air leave under some uncertainty. 

178. Conversely the specific heat of air maybe determined 
from hygrometric observations. This has been done by Dr. 
Apjohnf. 

179. The value of m manifestly depends upon the unit of elas- 
ticity, and upon the imit of temperature. 

180. Dr. Apjohn, of Dublin, whose attention was directed to 
the subject by the suggestion of the Committee of the Associa- 
tion, has, in a series of interesting papers, tested the value of m 
in a variety of circumstances by his own experiments |, and by 
those of others §. Assuming De la Roche and Berard's value 
of the specific heat of air, he finds m, for English inches of 
mercury, and for Fahrenheit's degree, to be -^j = '01149 : a 
posteriori he has determined it — 

(1.) from experiments on the dew-point . . . '01151 
(2.) „ on refrigeration in dry air . '0115011 

* This formula, employed by Augusta and Bohnenberger, coincides essen- 
tially with that of Ivory (Phil. Mag.Tx. SO.), who first gave a proper theory of 
the moistened bulb hygrometer. His value of m is not far from the truth, 
being J- for cent, degrees, or ' for Fahrenheit. 

•f- Irish Trans., Phil. Mag., and Brit. Assoc, Sixth Report. See also Suer- 
man's Thesis. 

+Phil. Mag., 3rd Series, vii. 266. 470. § Ibid., vi. 182. 

II Prof. Lloyd has ingeniously made this set of experiments the means of 
testing the accuracy of the tables of the force of vapour, and he prefers Dalfon 
and Ure's calculated by Anderson.— Proceedings, Royal Irish Academy, 1840. 



SUPPLKMEN'TARV REPORT ON MBTEOROLOGY. 99 

(3.) from experiments on refrigeration in air once 

saturated, then warmed '01140 

nearly coincident with one another, and with the theoretical 
determination. 

181. Bohnenberger* had already obtained a value sensibly 
identical, which probably was not known to Dr. Apjohn at the 
time he made his experiments ; for English inches and Fahren- 
heit degrees, he obtained — 

First, from 56 observations m = '0114 

Afterwards, from 45, which he preferred . '011398 

182. M. K'amtz, in a very valuable paper f on the results of his 
extensive observations in Switzerland, has given his formula in 
a slightly different form, but which indicates an almost precise 
coincidence between theory and experiment, both for the case 
where the thermometer is above freezing and below ; for in the 
latter case equally the principle holds, only we must allow for 
the latent heat absorbed in liquefying as well as vaporizing the 
water. Including the barometric formula, M. Kamtz writes 
the second term of the formula for the elasticity thus : 

- 0*001004475 {t — t') b, 

b being the barometric height in French lines, the standard 
barometric height 336 lines, by which the co-efficient (which is 
for Reaumur's scale) has been already divided. 

183. The above expression is the theoretical one above 0° R. 
The theoretical one below 0° R. is 

- 0-0009375 {t - t') b. 

184. These two numbers, deduced a posteriori from the Swiss 
observations, give 

AK^„o no t> /Faulhorn . . '0010026 34 obs. 

Above R.|Rigi. . . . -001002506 31 „ 

TJ^i^^noo fFaulhorn . . -000945014 15 „ 
BelowO R.|z^rich . . . -0009995 11 „ 

from direct comparison with the dew-point. 

185. I have given these numbers, that their coincidence may be 
perceived. Again, to compare them with Apjohn's and others, 
we may take those at the Faulhorn and reduce them to English 
measures and a mean barometric pressure, when we shall 
obtain 

Above 32° Fahr. . . . m = -0118 
Below 32° Fahr. . . . m = -0112 

* Suerman, p. 88. f Poggendorff, xxx. 33. 

H 2 



100 REPORT — 1840. 

186. M. Kupffer*, though he adopts Kamtz's table of elastici- 
ties, after examinhig the experiments of Gay-Lussac, Bohnen- 
berger, Auguste, and Erman, finally prefers this value of m, 

Above 32° m = -01135 

almost coincident with that of Bohnenberger and Apjohn. 

187. A most elaborate paper has been published by Mr. Prin- 
sep, of Calcutta, in the Journal of the Asiatic Society of Bengalf, 
on the wet-bulb problem, in continuation of the ingenious, but 
rather obscure ones, alluded to in the former report, as having 
been published in the " Gleanings of Science" j. Mr. Prinsep 
states, that the notice taken of his former labours, in the First 
Report of the British Association, had stimulated him to re- 
sume the subject, and he has accordingly furnished us with a 
great many valuable test-experiments, which can nowhere be 
so well performed as in warm climates. Mr. Prinsep's ori- 
ginal memoir will be consulted by those who wish to avail 
themselves of his valuable researches for the improvement of 
theory : it is not necessary to dwell upon those points where he 
seems to us to be less explicit, or historically not quite exact; 
and the great point is to be clearly satisfied that we have noiv ob- 
tained a sufficient interpretation of the indications of the moist- 
ened thermometer. When we find that Mr. Prinsep once more 
coincides with Dr. Apjohn's numbers, only hesitating whether 
to prefer -g-^ to -^j for the value of m, we are prepared to admit 
that this problem is, practically speaking, completely resolved ; 
and this being the case, it is scarcely worth while to disentangle 
the various imperfect steps by which so happy a consummation 
has been attained, and the hj grometer rendered as commodious 
and as accurate as the common thermometer §. The leading 
steps of the generalization are these : — Hutton invented the 
method ; Leslie revived and extended it, giving probably the 
earliest, though an imperfect theory ; Gay-Lussac, by his ex- 
cellent experiments and reasoning from them, completed the 
theory, so far as perfectly dry air is concerned; Ivory ex- 

* Bullet'iii de l' Academie des Sciences de St. Petersbourg, vi. No. 22, for 
which I am indebted to Major Sabine. 

t No. 55, .Inly, 1836. 

X The "Gleanings in Science" refei-red to in the original Report of the 
British Association, had been lent to me by Sir D. Brewster, to whom they had 
been sent. I afterwards communicated them to Dr. Apjohn. 

§ In practice, I am inclined to prefer two separate thermometers to the dif- 
ferential one of Leslie, which requires besides, the use of a common thermo- 
meter, to take the temperature of the air. It seems preferable to have two 
thermometei-s arranged in one pocket-case, and in the event of fracture a single 
one may still be used. I have formerly adverted to the unnecessary introduc- 
tion of the term psychrometer to e.xpress so simple a combination. 



SUPPLEMENTARY REPORT ON METEOROLOGY. 101 

tended the theory ; which was reduced to practice by Auguste 
and Bohnenberger, who determined the constant with accuracy. 
English observers have done little more than confirm the con- 
clusions of our industrious Germanic neighbours ; nevertheless, 
the experiments of Apjohn and Prinsep must ever be considered 
as conclusively settling the value of the co-efficient near the 
one extremity of the scale, as those of Kamtz have done for 
the other. 

188. Of the papers of Dr. Hudson in the Philosophical Maga- 
zine*, and of Mr. Meikle, and of an anonymous author, in the 
Edinburgh New Philosophical Journal t, it is not necessary for 
me to speak, on the grounds just stated. The experiments of 
the latter have been compared with theory by Dr. Apjohn. 

B. On the Distribution of Vapour in the Atmosphere. 

189. Now that we have got a simple and intelligible hygrome- 
ter, we may hope to know more than we yet do respecting the 
distribution of vapour in the atmosphere. Accurate experiments 
are at present extremely rare ; a few of the most interesting 
have been obtained by M. Kamtz. The greatest dryness he 
has observed was on the 28th September, 1832, on the summit 
of the Faulhorn, the barometer 247*4 French lines. At 9 a.m. 
the temperature of the air was 6°-9 R., the moist thermometer 
fell to 0°*1 R. The computed dryness is 9 per cent, of satura- 
tion J. Clouds he has always found to be perfectly damp when 
fully immersed in them, confirming the result of Saussure, 
which has been called in question §. 

190. It has commonly been supposed that dryness increases 
as we ascend ; yet it is also certain, that at a certain elevation 
clouds are more common than at any other. Accordingly, 
Kamtz finds that, whilst in dry weather the higher regions are 
drier than below, in damp weather the reverse is the case j he 
finds that, if we consider the absolute elasticity of vapour at a 
given place, there are two maxima and two minima daily ; but 
if we consider the relative humidity, or proportion existing to 
the capacity of saturation, there remains but a single maximum 
of dampness at 4-5 a.m. (in June), and one minimum at 

2 P.M. 

191. The absolute quantity of moisture existing in the air is 
greatest at the equator, and diminishes towards the poles. M. 
Kamtz, from the experiments of Beechey and others, gives the 
following formula || for the North Atlantic : — 

* Phil. Mag., 3rd Series, vii. viii. ix. t xv. 273 ; xvii. 98. 330. 

X PoggendorfF, xxx. 71. § Poggendorff, xxx. p. 53, 

II Poggendorff, xxx. 59. 



102 REPORT— 1840. 

E^ = 0-1370 + 8-9004 cos'' <f> in French lines, where E^ is 
the elasticity of vapour in lat. 0. 

IV.— Wind*. 

192. The immediate cause of wind is the inequality of pneu- 
matic pressm*e in the atmosphere, occasioned by differences 
(permanent or variable) of temperature. 

193. Of Permanent Differences, the most important is the 
warmth of the equatorial regions compared to the polar. The 
combination of this cause with the rotation of the earth is the 
well-known cause of the trade winds ; and, we may add, of the 
prevalent west winds in northern latitudes, as well as of the 
counter currents observed at certain elevations. 

194. Of Variable Differences of temperature there are very 
many; — as (1) the variable temperature of any spot, occasioned 
by the annual change of position of the sun respecting it ; (2) a 
similar variation for different hours of the day or night; (3) a 
variation due to the continental and insular character of climate 
affecting the annual temperature curve ; (4) a similar influ- 
ence of the solid or fluid, and more or less heat-absorbing, cha- 
racter of the surface, in varying the distribution of temperature 
during twenty- four hours ; (5.) the variable nature of surface 
depending on elevation, such as the presence of mountains, 
which receive heat from and part with it to the adjacent plains, 
according to different laws. 

195. All these causes produce their peculiar and local effects, 
which it may be sufficient to advert to in the most general way. 
To the /irst cause is due the variation in the position of the 
limit of the trade winds at different seasons. To the second, 
the probable tendency of the warmth at the part of the earth's 
surface, on which, in his diurnal course, the sun has just exer- 
cised its greatest enei'gy, to attract the colder air from the parts 
of the earth on whose horizon he is just appearing. To the 
third, are attributable the very important effects of the mon- 
soons, the local variations of the trades (as on the coast of 
Africa and Mexico f), the prevalence of east winds in Europe 
in spring, and many similar phaenomena. To the fourth, the 
recurrence of land and sea breezes in all climates, especially 
between the tropics. To the Jifth, the very remarkable but 
little-noticed diurnal phaenomena of hill and valley breezes, 
occurring with great regularity in mountainous countries having 
a pretty vmiform climate (as in the South of Europe), and 

* See former Report, p. 246. Malilniann, p. 155. 

t See Capt. Hall's Fragments of Voyages and Travels, 2nd Series, ii., and 
Daniell's Meteorological Essays, 2nd Edition. 



SUPPLEMENTARY REPORT ON METEOROLOGY. 103 

which, especially in their connexion with moisture, have a most 
important influence on climate. 

196. All these phfenomena deserve a more careful examination 
than they have received, with a philosophical view of referring 
them to their common cause. What has been done in this way 
we will presently notice. But first, we will say something as 
to means of investigation. 

A. Anemometers. 

197- In my former report I remarked, that if anything were to 
be done in the way of anemometrical observations, it must be by 
the use of self-registering instruments. Two such have been 
invented, and pretty extensively used in this country. 

198. Mr. Whewell* has described an anemometer proceeding 
on the ingenious principle, that the meteorological importance 
of a wind blowing in a given direction is not to be estimated by 
the number of days or hours that it blows in a given direction, 
but by the compound ratio of the time and force. This he 
endeavours to obtain by causing a pencil to describe a vertical 
line with a velocity proportional to the nvunber of turns of a 
vane with which it is connected, whilst at the same time the 
pencil is carried round a cylindric surface by an apparatus like 
that which guides a windmill, so as to point out the azimuth of 
the wind. The length of line described by the pencil between 
two given azimuths shows the integral effect of force and time 
for that interval. The instrument has been worked with very 
considerable success at Cambridge, under the directions of 
Professors Whewell and Challist, at Plymouth by Mr. South- 
wood J, at Edinburgh by Mr. Rankine§ and myself, and in 
other places. From its construction (friction being the anta- 
gonist force or regulator), perfect comparability cannot be ex- 
pected. 

199. Mr. Osier, of Birmingham, has invented and constructed 
an ingenious but complicated apparatus for measuring the force 
and direction of the wind at any moment, and for keeping a re- 
gister of these particulars in the absence of the observer || . It 
consists of a very powerful vane, which carries round the stalk 
to which it is affixed ; this stalk terminating in a pinion, moves 
a rack connected with a pencil, which describes upon paper the 

* Cambridge Transactions, vol. vi. part ii. 

f Britisli Association, 7th Report, Sections, p. 32, and Camb. Transactions. 

X Ibid., 8th Report, p. 28. § Edin. Trans, xiv. 359. 

II British Association, 7th Report, Sections, p. 33, and " Description of a 
Self-Registering Anemometer and Rain-Gauge." 4to. Birmingham, 1839, 
with a plate. Some parts of the apparatus have been more lately modified. 



104 REPORT — 1840. 

variations in the direction of the wind, the paper being carried 
uniformly along beneath the pencil by means of clockwork, so 
that the pencil describes a Curve of Direction of the Wind. The 
force is registered by means of a plate one foot square con- 
nected with the vane-stalk by a jointed parallelogram ; which 
plate is pressed against a spiral spring in such a manner as to 
indicate the force of the wind by the antagonist force of the 
spring in pounds. To indicate this upon the same sheet of 
paper before mentioned, and with regard to time, a thread con- 
nected with the pressure plate is conveyed through the axis of 
the vane-stalk (which is hollow), and then turning over a 
pulley, pulls a pencil up or down as the intensity increases or 
diminishes, leaving an intelligible tracing on the paper, from 
which the mean pressure may be tolerably estimated*. The 
fall of rain is registered by a peculiar contrivance upon the 
same sheet, so as to indicate its amount and distribution over 
the twenty.four hours. The expense of the instrument and its 
liability to derangement are the chief objections to it ; it is evi- 
dent that so many objects cannot be gained without consider- 
able complication f. One of these anemometers has been work- 
ed for a considerable time at Birmingham, and another at Ply- 
mouth J. One has just been established at Edinburgh, and 
others, it is believed, have been sent to Ireland and America. 

200. Mr. R. Adie, of Liverpool, has contrived a statical wind- 
gauge, in which the maximum pressure is pointed out. It is 
on the principle of a gasometer with a moveable top, over 
water, and the pressure of the wind is introduced by a tube 
below. The pressure is indicated by a hand connected with an 
axis, which is turned as the moveable top rises against a gra- 
duated resistance §. 

B. Phcenomena of Wind generally. 

201. It is rather remarkable that of late years several persons 
should independently have arrived at partial solutions of the 
great and complicated problem of aerial currents, their distribu- 
tion and causes. A few of the simpler admitted facts have al- 

* As every instrument upon this construction must necessarily act by im- 
pulsive starts, the statical gradation cannot possibly give the actual force of the 
wind, but it is difficult to suggest a better measure. 

t This instrument is in every respect so much more complicated in its parts 
and delicate in its adjustments than Mr. Whewell's anemometer, that it is 
difficult to understand how the latter comes to be described in the Royal 
Society's Instructions (p. 71.) as "more complex in its construction, and prac- 
tically more liable to derangement." 

X See Reports of the Ninth Meeting of the British Association. 

§ See a figure in Dr. Traill's article on Physical Geography, from the Ency- 
clopcrdia Britannka, 8vo, p. 197. 



SUPPLBMBNTARY REPORT ON METBOROLOGY. 105 

ready been mentioned, which serve to explain the more formal 
modifications of wind by a combination of the principles of 
rarefaction by heat, and the mechanical rotation of the globe. 
The particle of air, thus drawn toward the equatorial regions 
by the rarefaction permanently produced there by the sun's 
verticality, lags behind the parallel of latitude over which it 
moves, having the velocity due to a higher latitude from which 
it has come. That there must be a return current is not only 
evident to common sense, but its existence is made evident by 
the drift of clouds in the neighbourhood of the tropics, and by 
observations at great elevations ; not to mention that the preva- 
lent S. and S.W. winds of our latitudes appear to be nothing 
else than portions of this superior return current, which, in this 
stage of its progress, falls again to the surface of the earth, pos- 
sessed of the excess of velocity of a more southern parallel. 

202. These doctrines are now generally held, but there have 
been various attempts made to carry out the theory and to ge- 
neralize the facts further, even as respects the apparently capri- 
cious changes of wind in this most anomalous region of the 
earth's surface. It even appears probable that our forefathers 
knew more on this subject than is generally admitted now, 
and the sagacious guesses of the seventeenth century may be 
brought in supportof the jyroZ»a;6/e theoretical conjectures of the 
nnieteenth. 

203. Professor Dove, of Berlin, author of several original re- 
searches in meteorology, optics, and magnetism, and editor of a 
valuable scientific work of reference*, has published a series of 
elaborate memoirs more or less connected with the theory of 
windf, of which he has more lately published a compend J, but 
whose labours on this subject seem to be little, if at all, known 
in this country. This perhaps is to be attributed to the want 
of a perspicuous analysis of his views by some one who would 
undertake clearly to state, how far they are original and how 
far combined from those of others, how far they are to be con- 
sidered hypothetical and how far founded upon demonstration. 
We feel the want of some such guide in turning over Prof. Dove's 
three hundred and forty-four closely-printed pages, and also in 
the writings of his countrymen who have acted as comnien- 
tators§. I am by no means satisfied that T am so thoroughly 
possessed of his views as to give all that Prof. Dove claims to 

* Repertorium, of which 3 volumes are published. 

\ A list of 14 memoirs contained in PoggendorfF's Annals between the 
llth and 36th vols, will be found in his " Untersuchungen," p. viii. 

X Meteorologische Untersuchungen, von H. W. Dove. Berlin, 1837. 8vo. 

§ Fechner, in his iZepe/'ton'Mffi, vol. iii. ; ^a,ri\tz,'mh\s Meteorologie, i. 254; 
Muhlmann, in his enlarged Translation of my last Report, p. 155. 



106 REPORT— 1840. 

establish, but in stating briefly what I understand to be his 
fundamental positions, I shall at least have a better chance of 
rendering myself understood, than if I confined myself to the 
easier task of translating passages from the original works. 

204. Considering first the simple phsenomenon of the direc- 
tion of the tvind, apart from all others, it appears for ages to 
have been a belief that when the wind changes it does so in a 
constant direction, which is that of the hands of a watch, 
which for brevity we will call a Right-handed Rotation. 
M. Dove contrasts, not unaptly, the two following passages, 
one from Bacon, in the commencement of the l7th century, 
the other from a French physical writer of the 19th. The 
former says, " Si ventus se mutet conformiter ad luotum solis, 
non revertitur plerumque aut si hoc facit fit ad breve tempug ;" 
the latter, "On a cru remarquer que dans certains lieux les vents 
se succedent dans un ordi*e determine ; mais ces observations 
presentent encore trop d'incertitudes pour qu'il nous soit per- 
mis de les discuter ici". The clear evidence which Dove pro- 
duces of the opinion of observers of various countries during a 
space of tvvo hundred years, that the more frequent and more per- 
manent rotations of the windare right-handed (in this hemisphere), 
give much support to his theory*. It is important to add, that 
the pheenomena of the trade winds and monsoons enter as part 
of the expression of his general law of rotation [das Drehimgs- 
gezetz des Windes). 

205. It is very remarkable, from its connexion with a different 
inquiry presently to be noticed, that in the Southern Hemisphere 
the Law of Motation is inverted, the movement of direction is 
Left-handed. In the Northern Hemisphere the order of winds is 

S., W., N., E., S. 
In the Southern Hemisphere, 

S., E., N., W., S. 
Of these circuits, the quadrants from S. to W. and N. to E. 
in the Northern Hemisphere, and from N. to W. and S. to E. 
in the Southern Hemisphere, are oftener traversed in an inverted 
order than the opposite quadrants f. 

206. This, however, is only a small part of M. Dove's investi- 
gation, for he aims at showing that this law of succession thus 
determined, renders a certain order of meteorological phaeno- 
mena of every kind indispensable, and he has laboured to assign 

* Meteorologische Utitersuchungen, p. 132. It is important to observe, that the 
direction of rotation here mentioned has no reference to the rotatory movement 
of the aerial particles themselves, which will be referred to in the next section. 

t Meteorologische Untersuclningen, p, 129. It is to be observed, that this 
Law of Rotation especially applies to extra-tropical regions, where the mixture 
of equatorial and polar currents is most complete. 



SUPPLEMENTAEY REPORT ON METEOROLOGY. 



107 



for each hemisphere an invariable concomitance of the meteor- 
ological phasnomena of temperature, pressure, humidity and 
rain for every direction of the wind. This research was 
indeed by no means new. Von Buch had shown the depend- 
ence of the barometer on the direction of the wind ; even the 
poets could distinguish the thermal and hygrometric charac- 
ters of Boreas and Zephyr ; and it is easy to see that as far as 
the characters of North and South go, these particulars must 
be altered in the southern hemisphere. In my former report 
I have shown, from the researches of the German meteorolo- 
gists, that the mean direction of the wind for the whole year 
depends on the climate*, and I might have added that the sea- 
son exerts an important influence : — 

207. Thus at Berlin the mean direction of the wind is f 

Proportion of 
E. to W. Winds. N. to S. Winds. 
33° W. . . . 100 : 137 • . . 100 : 190 
73° W. . . . 100 : 132 . . . 100 : 113 
83° W. . . . 100 : 277 . • . 100 : 85 
50° W. ... 100 : 160 . . . 100 : 167 
Each season therefore has its predominant wind, as it has its 
characteristic temperature, pressure and moisture. It is Prof. 
Dove's object to prove that these follow as cause and effect, and 
hence that any law affecting the succession of winds must affect 
the succession of other meteorological pheenomena. It must 
be owned that the following table of one year's observations at 
Calcutta give a strong probability to the gejieral mutual de- 
pendence of these pheenomena upon one another in those regions, 
where atmospheric laws are usually exhibited with vast dis- 
turbance, and therefore more correctly (at least in proportion to 
the time that the observations have been continued). 



Winter S. 
Spring S. 
Summer N. 
Autumn S. 



Month. 


Temp. 

Fahren. 

belt. 


Rain, 
Inch. 


Barom. 
Inch. 


Wind. 1 


Direction reckoned 
from S. by W. 


Approx. 
Direction. 


January ... 
February . 
March ... 

April 

May 

June 

July 

August ... 
September. 
October ... 
November. 
December . 


66-6 

75 

79 

82-5 

86 

83 

83 

83 

83 

83 

75 

69 


2'9 

0-5 

8-0 

6-0 

24-4 

12-8 

9-3 

11-7 

1-4 

0-5 


30-08 
3002 
29-95 
29-83 
29-77 
29-58 
29-59 
29-62 
29-71 
29-91 
29-98 
3001 


156° 
80 
355 
337 
348 
321 
314 
299 
285 
94 
118 
135 


N.N'.W. 

w.s.w. 

s. 

S.S.E. 

S.S.E. 

S.E. 

S.E. 

E.S.E. 

E.S.E. 

W. 

W.N.W. 

N.W. 



* p. 246. 

t From the Observations of Beguelin, for 1 7 years. See Kanitz and Mahlmann. 



108 REPORT 1840. 

208. "Since 1827," says Prof. Dove, "I have published a series 
of Memoirs in Poggendorff's Annals, in vrhich I have sought 
to prove that the totality of the non- periodic meteorological 
changes of our latitudes reduces itself to a fundamental phceno- 
menon, which I have called the Law of Rotation of the Wind. 
The fact of a regulated variation of the direction of the wind 
(regebndssigen Ueberganges der verschiedenen JVindesrich- 
tungen) observed centuries ago, yet often disputed, stood iso- 
lated from the generally acknowledged, if not sufficiently proved, 
influence of the winds' direction upon the pressure, tempera- 
ture and humidity of the atmosphere. If, then, the so-called 
Irregular Variations are nothing else than the transition or 
passage of the barometrical, thermal and hygrometrical values 
of the winds into one another, it is clear that the laws of these 
variations can only be known by ascertaining the laws which 
connect the mean variations of the wind's direction with the 
distribution of pressure, temperature and moisture for the 
different points of the compass*". Such nearly, in the author's 
words, are the objects of his more laborious investigations; and 
to the construction of a barometric compass-card, a ther- 
mometric compass-card, and so forth, a series of memoirs is 
devoted. When by this means any mean series of meteorolo- 
gical changes becomes interpretable in terms of wind-azimuth, 
it is easy to see that new checks may be obtained for the fun- 
damental law of rotation. 

209. To pursue the course of M. Dove's laborious research 
is out of the question. We must content ourselves by gi- 
ving a specimen of his conclusionsf. In the Northern hemi- 
sphere 

The Barometer falls during E. S.E. and S. winds ; passes 
from falling to rising during S.W. and rises with W., 
N.W. and N. winds, and has its maximum rise with N.E. 
wind. 

The Thermometer rises with E., S.E. and S. winds ; has 
its maximum with S.W., and falls with W., N.W. and 
N. winds ; its minimum is N.E. 

The Elasticity of Vapour increases with E., S.E. and S. 
M'inds ; has its maximum at S.W., and diminishes during 
the wind's progress by W. and N.W. to N. ; at N.E. it has 
a minimum. 

210. What has now been stated for the Northern hemisphere 
may be transferred to the Southern by changing N. into S., 
N. W. into S.W., &c., throughout. 

211. These views of Dove have not been received altogether 

* Untersuchungen (Pref.). + Untersuchungen, p. 140. 



SUPPLEMENTARY REPORT ON METEOROLOGY. 109 

without discussion. The mutual dependence of meteorological 
phaenomena in a general way can hardly be disputed, but the 
fundamental Law of Rotation has been denied by Schouw, who 
has made this subject his particular study*. The subject now 
attracts considerable attention in Germany f, and the indications 
of anemometers, like Osier's, are well adapted to put it to the 
test. 

C. Phcenomena of Storms^. 

212. The ingenious observations of Franklin on the travelling 
of storms opposite to the actual movement of the wind which 
produced them, led to the supposition of local rarefactions 
and the sudden rush of wind from all quarters to supply the va- 
cuity. The enormous linear velocity of the aerial particles re- 
quired to produce the observed effects, to which might be added 
the difficulty of conceiving this propagation of disturbance to 
continue for days together, and to pass over hundreds or thou- 
sands of miles, with unabated intensity, led Colonel Capper to 
suggest in 1801 §, that the velocity of the wind at any point was 
chiefly due to the velocity of rotation of a vortex of fluid, com- 
bined probably with a progressive motion. Pi-of. Mitchell, of 
America, seems to have retrograded when he assigned to the 
gyration a vertical plane of motion ||; but he was speedily fol- 
lowed by Redfield, who, doing all justice to those who preceded 
him, established Colonel Capper's doctrine by a diligent appeal to 
facts ^. Mr. Redfield has been fortunate also in having a Eu- 
ropean fellow-labourer in the same field, who has been equally 
candid in his acknowledgements of what he borrowed from Ame- 
rica. Colonel Reid, in a handsome and elaborate work**, has 
maintained the same views, and supported them by an examina- 

* See Kamtz, i., 257, and Pogg. xiv. 546. See also Schouw's extensive 
Essay on the Winds of Europe, " Beitrdge", &c., p. 1 — 115. 

t See Galle's papers on the Extension of Dove's Law to the Southern He- 
misphere, Poggendorff, xxxi. 465 ; xxxviii. 472. 

X First Report, p. 248. 

$ In a work on the Monsoons and periodical winds, quoted by Redfield, Reid, 
and others. 

il Silliman's Journal, 1831, xix. 248. 

^ His first paper is in Silliman's Journal, 1831, xx. 17. There is a reply 
to him by Mitchell in the same volume. See also London Nautical Magazine, 
April, 1836, and Jan. 1839, and Silliman, xxx. 115. 

** On the Law of Storms 8vo. London, 1838. An interesting review of this 
work, and of the previous labours of Redfield, will be found in the Edinburgh 
Review, Ixviii. 406, to which those readers who wish a popular compend of 
the subject are referred. Since these pages were written, Prof. Dove has ex- 
plicitly claimed the credit (Phil. Mag., Nov. 1840,) of having first in recent 
times asserted the revolving and progressive character of storms, and their op- 
posite character in the two hemispheres. — Compare Pogg. xiii. 596. 



110 REPORT— 1840. 

tion of the courses of many hurricanes recorded in ships' logs, 
which he has projected on excellent chai'ts. The theory of 
Colonel Capper proposed for the storms of the eastern hemi- 
sphere is found to be not less applicable to the terrific tem- 
pests of the West Indies, where these gyratory movements ap- 
pear commonly to take their rise, invariably revolving from 
right to left, which at the same time pi'ogress in a straight 
or curved path, usually occupying a space of from 100 to 500 
miles in diameter. These rotatory movements commence in 
tropical latitudes usually near the West India Islands ; they 
move at first in a westerly and continually more northerly di- 
rection, until they reach a latitude of about 30°, when they turn 
rather abruptly tovvards the north-east. It is impossible not to 
believe that the path of these storms is mainly determined by 
the configuration of the American continent*. 

213. The fall of the barometer, especially near the central 
parts of the storm, is accounted for by the action of centrifugal 
force. 

214. It is very evident that the direction of the wind to a sta- 
tionary observe!-, whilst one of these vortices is passing over 
him, will vary in a manner depending on his position with respect 
to the axis of the storm. If the centre pass rigorously over his 
station, he will experience a gale first in one direction and then 
in a directly opposite one, without any intermediate points of 
the compass ; as an observer is stationed on one side of the axis 
or the other, a little reflection will clearly show that the appa- 
rent change in the wind's direction will follow opposite courses 
in the one or other position. This and many other deductions 
are fully made by Redfield and Reid ; we only mention it just 
now in order to point out that this, at all events, must be con- 
sidered an essential exception to Dove's law of rotation. 

215. There is, however, a remarkable analogy to Dove's law 
in one respect, which is, that t/te direction of rotation of storms 
is opposite in the two hemispheres, being right-handed in the 
southern. This important fact was deduced by Redfield from 
his hypothesis that storms are produced by the mingling and 
collision of the superior equatorial stream with the polar stream 
or trade winds. Colonel Reid has given great support to this 
view by tracing some storms of the southern tropical regions. 

216. Not the least important and interesting part of this in- 
quiry is the deduction of practical rules for steering out of in- 
stead of into these vortices, an application distinctly pointed out 
by Col. Capper as well as his successors ; but this does not con- 
cern us at present. 

* See Colonel Reid's Charts, iii., v., vii. 



SUPPLEMENTARY REPORT ON METEOROLOGY. Ill 

217. The theory of Capper, Redfield, and Reid has not been 
received Mdthout opposition. Mr. Espy*, in particular, advo- 
cates the Franklinian doctrine of the progression of wind in radial 
lines ; and he has received the powerful support of Prof. Bache, 
of Philadelphia, who has described, in great detail, a tornado f 
which occurred in New Brunswick in 1835, and from which he 
finds no proof of rotation. Mr. Milne J has traced, I think 
satisfactorilj'^, the rotatory character of two remarkable storms 
which passed over the British Islands in November, 1838, ac- 
companied with an extraordinary depression of the barometer 
of a veiy local character. M. Arago is disposed to admit, that 
there may be hurricanes of both characters, and, consequently, 
observations irreconcileable with either hypothesis singly §. 

V. — Clouds — Rain || . 

218. The theory of the suspension of clouds, one of the most 
interesting in the whole range of meteorology, has received no 
additions, nay, it can hardly be said to exist. That clouds con- 
sist of distinct particles is vmdoubted, from optical phsenomena, 
and from direct observation^; the error seems to be, to con- 
sider these as so many independent molecules, whereas they are 
no doubt connected by the most definite laws of force, and con- 
stitute masses whose density has no necessary connexion with 
that of their integrant parts. No one can observe the cha- 
racter of clouds — for instance, the well- formed cauliflower- 

* Journal, Franklin Institute, October, 1836. Not having been able to pro- 
cure this journal, I cannot refer to the contents more particularly. Mi-. Espy 
maintains a peculiar physical theory of storms, which, since this report was 
■written, has been brought in several forms before the British public. — See also 
Silliman, xxxix. 120. Dr. Hare has published, in the American Philosophical 
Transactions, and in Silliman's Journal (vol. xxxviii.), some papers respecting 
tornadoes, in which he appears to assign to them an electrical cause. Major 
Sabine has referred me to a clear and able analysis of the effects of the storm 
of the 20th December, 1836, by Mr. I,oomis, in the first part of the 7th vol. 
of the American Transactions (which had not reached Scotland when this 
report was written), who appears to infer, in that particular case, a rotation 
round a horizontal axis like that imagined by Mitchell. The paper is highly 
worthy of consultation. 

t Trans. American Phil. Soc, v. 407. It seems rather singular, that the 
name of tornado or whirlwind should be applied, by common consent, to a 
storm not having the rotatory character. Mr. Redfield denies Mr. Espy's and 
Prof. Bache's conclusions (Nautical Magazine, January, 1839, p. 6.). See also 
the Report of the Newcastle (Eighth) Meeting of the British Association, 
where Colonel Reid and Prof. Bache were present. 

X Edinb. Trans., vol. xiv. § Comptes Rendus (Paris), vii. 707. 

II Former Report, p. 249. Mahlmann, p. 185. 

IT Since writing the former report, I have satisfied myself of the existence 
and some of the phasnomena of Saussure's (so called) vesicular vapours. 



112 REPORT — 1S40. 

headed cumulus contrasted with the flaky cirrus — without being 
persuaded of the fact, that clouds are not unorganized assem- 
blages of watery particles in a state of extreme division. 

219. With respect to the fall of rain, by far the most inter- 
esting contribution to tliis part of meteorology, took its origin 
at the rise of the British Association. Prof. Phillips, by his 
careful experiments on the fall of rain at different elevations at 
York, and his admirable deductions fi'om them, has (I think) 
completely established the cause of the diminished fall of rain, 
as we ascend in the atmosphere (vertically above the soil). M. 
Boisgiraud ain^, of Toulouse*, was, I believe, the first in 
recent timesf to maintain that this is due to the gathering of 
the drop as it descends, chiefly in consequence of the cold 
which it possesses, due to the height from which it lias fallen, 
and also to the considerable dampness of the atmosphere at 
such times. This, the experiments of Mr. Phillips and Mr. 
Gray entirely confirm, and I think demonstrate J. 

220. For 12 months (1833-31) the fall of rain at York was 
as follows : — 

Height above Ground. Rain in Inches. 

feet 25-706 

44 „ 19-852 

213 „ 14-963 

The diminution was, therefore, 41-8 per cent, for 213 feet. 

22-8 44 

which is pretty nearly as the square root of the height. This 
proportion does not hold for different seasons ; and though the 
formula m -v^ height, originally proposed by Mr. Phillips (m 
being a function of the air-temperature), is a tolerable approxi- 
mation, it does not appear to be an accurate one. Nor indeed 
have we any reason to suppose that so simple a law should 
express the effect, on the author's own hypothesis, since (ad- 
mitting that the rain-drops have attained a terminal velocity) 
the deposition on the drop must involve the size of the drop, 
the dryness of the air, and the decrement of temperature in the 
atmosphere in a very complicated manner §. 

221. Admitting, however, for a moment, Mr. Phillips's ori- 

• Annales de Chimie, xxxiii. 417. 

t Prof. Bache, of Philadelphia, has claimed, with reason, for Dr. Franklin, 
the merit of first suggesting the explanation, so far as the imperfect science of 
his time would fairly allow him to do. — Journal, Franklin Institute, vol. xvii. 
183G. 

X British Association, 3rd Report, p. 401 ; 4th Report, p. 560; 5th Report, 
p. 171. 

§ The optical phsenomena of the rainbow, to which we shall presently ad- 
vert, confirm, in a remarkable manner, the increased size of drops in falling. 
— See Arago ; Annuaire, 1836, p. 301. 



SUPPLEMKNTARY REPORT ON METEOROLOGY. 113 

ginal approximation, we think that he has fully made ont his 
main point ; for he has shown* that the value of the co-efficient 
m depends upon the dryness of the air, at least that it is very 
nearly inversely as the mean daily range at any season, a datum 
which, in a good degree, indicates the relative dryness ; altliough 
without direct hygrometrical experiments the investigation must 
be considered as incomplete. Mr. Phillips desires that these 
experiments should be further pursued at points where three 
rain stations, vertically above one another, can be procured, 
and he has given instructions for making such observations f- 

222. Prof. Bache, of Philadelphia, has shown the very mate- 
rial influence which the eddies of air surroundiug a station, such 
as a tower or steeple, exert upon the fall of rain, depending on 
the position of the gauge J. Mr. Phillips is at present engaged 
in an ingenious series of experiments, to estimate and elimi- 
nate these disturbances. 

223. An admirable list of rain-gauge experiments, in differ- 
ent parts of the earth's surface, is given in Prof. Muncke's ar- 
ticle on Rain, in Gehler's Physikalisches fForterbuch^, an 
elaborate treatise, which appears to exhaust the literature of the 
subject. 

224. It appears from the Report of the Birmingham Meeting 
of the British Association, as given in the Athenaeum journal ||, 
that doubt has been thrown upon the statement of the remark- 
able fall of rain cited in my former report^. I was not pre- 
sent at either of the discussions alluded to ; I therefore take this 
opportunity of stating the authority upon which these very sur- 
prising falls of rain were admitted into my report — authority 
so ample, that, as a historian of science, I could not have 
omitted them, improbable as they do most certainly appear. 

225. The fall of 30 inches of rain within 24 hours took place 
at Genoa** on the 25th October, 1822. An assertion to this ef- 
fect having appeared in a Genoese newspaper, the editors of the 
Bibliothhque Universelle wrote immediately to make the ne- 
cessary inquiries as to an observation so unprecedented. The 
reply, which they obtained from M. Pagano, " observateur 
exact," is given at length in this journalff, and is, I think, by 
no means the less satisfactory because it was obtained by the 
most inartificial of rain-gauges : — "Deux sceaux de bois, presque 
cylindriques, dont I'un de vingt-quatre et I'autre de vingt- 

* British Association, Third Report, p. 410. 

t Ibid., .5th Rep., p. 178. % Ibid., Eighth Report, Sections, p. 25. 

§ Vol. vii. Part II. p. 1309. Leipzig, 1834. 

II 31st August, 1839, p. 658. Ij P. 252. 

** Not Geneva, as stated by a printer's oversight in the former report ; the 
MS. was correct. 

tt Vol. xxii., Partie Physique, p. 67. 
VOL. IX. 1840. I 



114 REPORT 1840. 

six pouces de hauteur, qui m'avoient servi pour quelques expe- 
riences sur la vendange etoient restes vides dans mon jardin. 
La pluie de Vendredi 25 Octobre, n'avoient pas encore cesse 
de tomber, que deja ils en etoient remplis." He tlien pi'oceeds 
to state on what grounds he infers that 4 inches more of rain 
fell after the largest vessel was filled, making a total of 30 
French (32 English) inches, and then adds a statement of 
several facts, to shov/ that the effects of this delnge in the 
neighbourhood bore a proportion to the magnitude of the 
cause. M. Arago, quoting the result, adds, " Ce resultat inoui 
inspira des doutes a tons les meteorologistes ; ou soupfonnait 
una erreur d'impression ; mais M. Pagano, observateur exact, 
a ecrit aux redacteurs de la Blhliotheque Universelle, une lettre 
qui met le fait hors de toute contestation'*." 

226. Fortunately, however, tliis local deluge (for it appears by 
the letter of M. Pagano to have extended but a very short di- 
stance), is nearly rivalled by a similar fact recorded in the South 
of France by an experienced observer (who seems to have been 
in the practice of measuring the fall of rain for twenty-tiiree 
years at least), M. Tardy de la Brossy, of Joyeuse, Dep. de 
I'Ardeche. M. Arago, who records the observation, and gives 
it the weight of his authority, does so in these words : — " Le 
9 Octobre, 1827, dans I'intervalle de vingt-deux heures, il est 
tombe dans la menie ville de Joyeuse, 29 pouces 3 lignes d'eau 
{vingt-neuf pouces, trois lignes) ; j'ecris le resultat en toutes 
lettres afin qu'on ne croie j)as a une f ante d'impi'essionf." 
When I add that these two results, surprising, and perhaps 
unexampled, as they are in the history of science, have, on 
account of the testimony by which they are estabhshed, been 
received not only in France I and Switzerland §, but in Ger- 
many || and England^, I conceive that they are undoubtedly 
entitled to stand pai-t of the history of meteorology**. 

227. I proceed to add a notice of a few other remarkable falls 
* Annales de Cliimie, xxvii. 207. t Annales de Chimie, xxxvi. 414. 

I By Arago and Pouillet (,P/ii/s. ii. 758.)- 

§ By the Editors of the BibliotMque Universelle. 

II By Muiicke (Gehler, vii. 1240.), Kamtz (Meteorology, i. 421.), and 
Mahlmann (Abriss. 200.). 

^ EnctjcIopcBdia MtfropolUana, Art. Meteorology, p. 120. 

** Mr. Espy has referred me to the fourth volume of Silliman's Journal for 
an account of a shower hardly less surprising. At Catskill (U. S.), Mr. Dwight 
ascertained that on the 26th July, 1819, between half-past 3 p.m. and 11 p.m., 
that is, in seven and a Italf hours, there fell into an empty barrel placed in an 
open space eighteen inches of water. A tub \h\ inches deep, and nearly cylin- 
drical, was filled before sunset. Since writing the above, another fact of the 
same character has come to my knowledge. On the 2.5th Nov. 1826, 
/A/;/y-//i/-ee inches of rain fell at Gibraltar within /«t'e«<//-s?a' hours. This in- 
formation I received from Professor Jameson, who believes that he had it from 
tlie late Col. Imrie. 



SUPPLEMENTARY REPORT ON METEOROLOGY. 115 

of rain, though there is nothing on record comparable to the two 
preceding ones. Flaugergues, the eminent meteorologist of 
Viviers, obtained, on the 6th September, 1801, 13 inches 2*3 
lines (14| English inches) of rain in eighteen hours*. On the 
20th Alay, 1827, there fell at Geneva 6 inches of rain in three 
hours f. At Perth, on the 3rd August, 1829, there fell |ths of 
an inch of rain in half an hour J. On the 22nd November, 
1826, I observed, at Naples, a fall of y^ths of an inch of rain 
and hail in thirty-seven minutes^. 

228. Were the equatorial records of the fall of rain as minute 
in respect of distribution as of total amount, we should doubt- 
less have records of enormous falls within twenty-four hours. 
None so recorded, that I am aware of, approach the results at 
Genoa and Joyeuse. From the total quantities measured, it is 
evident that the result, for particular days, must be enormous. 
Don Antonio Lago observed, at San Luis Maranham (2i° S. 
lat.) a fall of tiventy-three feet, 4 inches, 9*7 lines of I'ain in a 
yearjl. Roussin states^ (his account is confirmed), that at 
Cayenne (5° N. lat.) in February, 1820, there fell, in ten hours, 
10"25 inches of rain; and between the 1st and 24th February, 
twelve feet 7 inches. From observations in the Ghauts, it ap- 
pears that in the eastern hemisphere, in lat 18° N., 302"21 
inches of rain have been measured**, a quantity exceeding 
that stated on the authority of Roussin, and which was once 
considered almost incredible ; and of this quantity (25'2 English 
feet) nearly 10 feet fell in the month of July alone. 

229. I have formerly stated, that the fall of rain increases 
on mountains ff ; and the following statement of Schubler, as to 
the fall of rain at three stations, confirms the factJJ : 

Height. Depth of Rain§§. 

Tubingen . . 1000 feet .... 3572 

Schaichhof. . 1576 „ .... 3856 

Alp Genkingen 2400 „ .... 5513 

* Bihliotheque Universelle, viii. 132, quoted in Gehler. 

+ ^««. rfeCAi/n.,xxxvi.414. The mean ann?/a/rain at Geneva is only 30 inches. 

X Edinburgh Journal of Science, New Series, iii. 368. 

§ I do not know whether there exists a record of the fall of rain at Cler- 
mont, on occasion of the catastrophe of the Vnlley of Royat, a few years ago ; 
the amount, I presume, must have been very great, judging by the effects. M. 
Quetelethas recorded a remarkable fall of rain in Belgium {Compies Rendus, 
viii. 980.). II Humboldt, quoted by Muncke. 

If Silliman's Journal, iv. 375., quoted by Muncke. 

** Communicated by Colonel Sykes, at the Ninth Meeting of the British 
Association. — Athenceum, p. 658. Prof. Stevelly's inference from these results 
must, 1 presume, be erroneously reported. 

tt Former Report, p. 251. J+ In Gehler, vii. 1246. 

§§ The unit of measure is not stated. 

I 2 



116 REPORT 1840. 

Boussingault finds a contrary result in the tropics * ; but this 
fact admits of easy explanation, for the height to which they 
were carried had already passed the region of maximum humi- 
dity, above which, no doubt, increased dryness occurs : — ■ 

Metres. Inches. 

Marmato . . . 1426 171'2 — 154'4 in 2 different years. 
Santa Fe de Bogota 2641 100-.3 

230. Boussingault also notices that, between the tropics, it 
rains more in the night than in the day, which is the contrary 
of the case in Europe f. 

231. Where M. Osier's self-registering gauge is employed, we 
have the best means of determining the distribution of rain 
and the intensity of showers. 

232. On the somevvhat vague subject of the moon's influence 
on rain and weather, I must content myself with referring to 
the recent Memoirs of AragoJ, Brandes§, Baumann||, Eisen- 
lohr^, Howard**, Kamtzftj MarcetJ+, and Schubler§§. 

VI. Atmospherical Electricity ||||. 

233. This subject has made scarcely any progress during the 
last years. The experiments of Schubler are still the best we 
possess. M. Arago has collected a number of important facts 
respecting thunder-storms, and drawn conclusions from them, 
for which we refer to his popular treatise ^^. Colladon, of 
Geneva, has proposed to make observations on atmospherical 

• L'Instituf, No. 143. 

t See also Schouw on the distribution of Rain. — Edinburgh Philosopliical 
Journal, July, 18.36. 

X Annuaire, 1833. 

§ Ueher die Verschiedenen Formen der Wollcen, ihre Bildung, die Entste- 
hung des Reg ens und Ilagels, ^c. — Beitrage, p. 285. 

II Unfersnchnngen iiber die Monatlicke Perioden in den Veranderungen 
unserer Atmosphdre. — Tubingen, 1832. 

^ Poggendorff, XXX. 72; xxxv. 141. 

** Proceedings of Royal Society, March, 1840. 

tt Lehrbuch, iii. 411, &c. XX Bibliotheque Universelle, Fev. 1834. 

§§ Einjluss des Mondes auf die Veranderungen unserer Atmosphdre. Leip- 
zig, 1830. — Kastner's Arcliiv, v. 169. 

II II See former Report, p. 252, and Mahlniann, p. 209, where the subject is 
very fully treated. 1 beg again to disclaim any depreciation of the importance 
of subjects like the present, over which I may pass very lightly, partly on 
account of the extent of this report, but chiefly because of the difficulty of 
establishing any general principles, and of offering any definite suggestions for 
their advancement. 

f ^ Annuaire, 1838. Translated in the Edinburgh Philosophical Journal. 



SUPPLEMKNTARY REPORT ON METKOROLOGY. 1 l7 

electricity by means of a multiplier, but with what success we 
have not heard*. 

234. On the subject of hail there is a curious paper by Lecoq, 
founded on observations made in the neighbourhood of Cler- 
mont, contained in the Comptes Mendus-f, and some observa- 
tions by Beaumont, Buch, and Airy, and on the form of hail- 
stones in the same work J. 

VII. Metbors. 

235. This subject has occupied by far too much attention 
during the last few years to be passed over in silence. A very 
remarkable shower of falling stars attracting general attention 
in many parts of the world on the night from the 12th to the 
13th November, 1832, recalled the attention of philosophers to 
the fact, that the same ?iig/)t of the year had, on several pre- 
vious occasions, been similarly distinguished, and especially the 
11 -12th November, 1799, when they were observed by Hum- 
boldt and Bonpland§, as well as in Germany and in Green- 
land ||. 

236. The year 1832 brought a very remarkable occurrence of 
this kind on the night of the 12-13th November, which was ob- 
served over the greater part of Europe, to the middle of Russia, 
and in Arabia. I was at Geneva at the time, and heard much 
next day of the appearance, which was such as to strike the 
most heedless person ; but as it occurred very early in the morn- 
ing, I did not see it. M. Gautier published an account of it^. 

237. This attracted attention to the date of the 12th Novem- 
ber, and several confirmations were soon found of the (at least 
occasional) periodicity of the meteor on that night. In 1831, 
they had been observed by M. Berard on the coast of Spain**, 
and also in Americaft- In 1822 they were seen at Potsdam 
by M. Kloden; and some other remarkable appearances in No- 
vember are also mentioned:]:^. But to return to the order of dates. 

238. In 1833 was a brilliant apparition, especially in America, 
always on the 12th November ; and these falling stars appeared 

* See on this subject the Instructions published by the Royal Society, p. 74 ; 
and Becquerel's Work, vol. iv., there referred to ; also Kauitz, Meteorvlogie, 
ii. 389. 

t Tom. i. p. 324. 

X iv. 922. On the subject of Hail, see Fecliner's Repertorium, iii. 56. 

§ Voyage, i. 519, quoted by Biot. || Arago, Jnnuaire, 1836, p. 295. 

^ Bibliotlieque Universelle, li. 189. See also Arago, Annuaire, 1836, p. 295. 
Jameson's Journal, July, 1836. Poggendorff, xxix. 447. 

** Annuaire, 1836, 295 note. See, too, Silliman, xxx. 386. 

tt Silliman's Journal, xxvii. 419. XX Poggendorff, xxxviii. 551. 



lib REPORT — 1840. 

to radiate from a point in the heavens near y Leonis. They 
Avere visible from Mexico to Greenland*. 

239. In 1834, the phaenomenon was less indubitably marked, 
for it scarcely appears to have been noticed in Europe ; and in 
America, observers were divided as to its amounting to any- 
thing unusual ; Prof. Olmsted, who was one of the first to sug- 
gest the periodicity, maintaining that November, 1834, was 
marked like the previous years f, and Prof. Bache denying it|. 

240. The year 1835 must be regarded as a very doubtful one 
for the November meteors. Still it happens, by what must at 
least be regarded as a singular coincidence, that a very large 
meteor was seen in France by M. D'Aubenton, which exploded 
in the department de I'Ain on the night of the 13th November, 
and probably set fire to a cottage §. Sir John Herschel saw a 
meteor as large as Venus at the Cape of Good Hope on the 
14th, but none on the 13th ||. 

241. The apparition of November, 1836, was better marked. 
The meteors were observed in America^. M. Arago, by ana- 
lysing various careful observations in France, has shown that, 
if not comparable to the showers of 1832 and 1833, they were 
at least numerically above an average**. They were observed 
in the Oural in lat. 60° ft, and their direction was from the 
constellation LieoXX. 

242. It may be doubted whether, in 1837, there was any 
very decided fall of meteors in November ; but I refer below to 
the recorded observations §§. The weather was not generally 
very favourable. 

243. November, 1838, was not more prolific. Scarcely any 
notice was taken of the meteors in the Comptes Reiidus, and 
the direct testimony of Quetelet, Herschel, and Benzenberg||||, 
show that the phsenomenon was, to say the least, not well 
marked. In America ^^I? it was scarcely, if at all, perceptible. 

244. In 1839, I am not aware that any very marked phse- 

* For 1833. See Silliman, xxv. 354 ; xxvi. 132; xxix. 376. Poggendorff, 
xxxi. 159; xxxix. 114 (Greenland). 

t Silliman, xxix. 167. 

X Ibid., xxvii. 335 ; xxviii. 305 ; xxix. 383. See also Clarke in Silliman, 
XXX. 369. Poggendorff, xxxiv. 129. 

§ Comptes Rendua, i. 414. || Ibid., ii. 264. 

"^ Silliman, xxx. 386. ** Comptes Rendus, iii. 629. 

•ft Comptes Rendus, iv. 524. Xl See also Poggendoi-ff, xxxix. 353 ; xl. 484. 

§§ Olmsted in'Silliman, xxxiii. 379; Sir John Herschel, Transactions of the 
Meteorological Society, i. 77 ; Arago, Comptes Rendus, v. 759 ; Observations 
at Edinbvn-gh, Philosophical Magazine, Third Series, xii. 85. 

||;| Bulletin de I'Acad. de Bruxelles, lSo8, p. 730. 

iyi[ Olmsted in Silliman, xxxv. 368. A brilliant fall was seen at many places 
on the 6th December. See Herrick in Silliman, xxxv. 361 ; xxxvi. 355. 



SUPPLEMENTARY REPORT ON METEOROLOGY. 119 

nomeiion was observed. Under these circumstances, it is plain 
that we must use the term periodicity, as appUed to these me- 
teors, with caution. It is quite possible tliat some cause may 
determine their recurrence in November in preference to other 
seasons, and yet that the repetition may not be annual. 

245. It is well known that Chladui*, Brandesf, and Ben- 
zenbergj, have devoted their attention for a long time to these 
singular meteors; and it is perhaps surprising that we still 
know so little respecting them. The November periodic me- 
teor has of course given a fresh interest to these ; Biot has pub- 
lished an astronomical theory §. Bessel has shown that it is 
improbable that these meteors ever ascend\\. Erman has given 
a meteorological hypothesis connected with them, which we 
have before adverted to^; and Olmsted** and Wartmann ft 
have likewise written memoirs on the hypothesis of their pe- 
riodicity. 

246. But M. Quetelet, of Brussels, examining the records of 
this subject, has classified the frequency of meteors at different 
seasons of the yearJt \ '"id whilst he finds the middle of No- 
vember the most prominent period, yet that from the 10th to 
the 15th August is also well marked. This observation, com- 
municated to the Brussels Academy 3rd December, 1836 §§, 
was confirmed by M. Arago next year||||, and, I belitve, every 
subsequent one^T[. In 1839 they appear to have been very 
generally observed. M. Quetelet has quoted no less than six- 
teen years in the present century down to 1837, in which the 
August meteors have been specially noticed***. 

* Feuermeteore. See Kiimtz, Meteorologie, Band iii. 

t See an Abstract of his Researches, Silliman, xxviii. 95 ; and in Quetelet's 
AnnnaJre for 1837. 

X He has published a new work, which I have not seen, " Die Sternschnup- 
pen." Hambourg, 1839. 

§ Comptes Rendus, ii'i. 6Go. II Poggendorff, xlvii. 525. 

^ See above (44), and Comptes Bendiis, x. 21. 

** Silhman's 3 oxxvuai, passim. 

■ft Bihliotheqiie Universelle, N. S. ix. 373. 

XX Catalogue des principales Apparitions d'Etoiles Jilantes. Mem. de I' Acad. 
de ButxeUes. 

§§ Bulletin de VAcad. de Bruxelles, December, 1836 and 1837, p. 79. 

nil Comptes Rendus, v. 183. 347; Silliman, xxxiii. 133; Bulletin de VAcad. 
de Bruxelles, 1838, p. 567. 

^f Ibid., vii. 443. torn. ix. passim. 

*** Bulletin, 1837, p. 379. M. Littrow, of Vienna, has observed the me- 
teors of August, and states that their direction of motion is contrary to that of 
the earth in its orbit, whilst those of November move parallel to it. {Atti 
degli Scienzali Italiani, 1839, p. 19.). I learn, by letters from Sir John 
. Herschel and M. Quetelet, that the meteors of August, 1840, have been ob- 
served both here and in America to radiate from a point near y Persei. Whilst 



120 REPORT — 1840. 

VIII. Aurora Borealis*. 

247. I have little information on this subject to offer in addi- 
tion to what was formerly given. It is to be regretted, that the 
system of observation, vigorously commenced by the British 
Association in 1833, and of which specimens are contained in 
the report of the Cambridge Meeting, has not been pursued. 

IX. — Optical Meteorology. 
A. Colour of the Sky ami Clouds. 

248. The blue colour of the sky has, from a very early 
period, attracted attention. Leonardo da Vinci f? and many 
succeeding writers, vaguely attributed it to a mixtiu'e of light 
reflected trom the matter of the atmosphere with the darkness 
of the celestial spaces beyond ; an opinion which Gothe has 
revived J. Muncke§ has asserted that the blueness is a mere 
ocular deception arising from the structure of the eye, but such 
a doctrine can hardly now be seriously maintained ; and I have 
elsewhere II offered an explanation of his fundamental experi- 
ment. 

249. Newton^ supposed that the blue of the sky is due to 
very attenuated vapours producing the first tints of the scale of 
the colours of thin plates. He further attributes the colours 
of sunset and of clouds generally, as he had done those of most 
natural bodies, to the vai-ying thickness of such vesicles**. 
The latter opinion has been revived and illustrated by No- 
biliff. 

250. Against this theory it may be urged, (1) that the sky 
appears intensely blue at elevations and under circumstances 
which forbid us to suppose that vapour can be present at all in 
a watery or vesicular form (which Newton's statement di- 
stinctly supposes), otherwise the hygrometer would attest its 
existence ; (2) that with respect to clouds, were they coloured 
by the nature of their surfaces as a soap-bubble is, they would 
present iridescent bands, and they would not partake, as we see 

this sheet is passing through the press, I am enabled to add that no decided 
meteoric appearance has been observed in Nov. 1840 at Paris, or in the West 
of Europe generally. 

♦ See last Report, p. 254. Mahlmann, p. 230. 

■f- Traite de la Peinture, quoted in Gehler's Worterbuch, art. Atmosphiire. 

\ Farbenlehre, i. 59, quoted by Humboldt. 

§ Schweigger's Journal, xxx. 81 ; and Gehler, ut supra. 

II Edinburgh Transactions, xiv. 381. % Optics, book ii., part iii., prop. 7. 

*• Optics, ibid, prop. 5, end. 

ft Bibliotheque Universelle, 1830, xliv. 337; and Taylor's Scientific Me- 
moirs, vol. i. 



SUPPLEMENTARY REPORT ON METEOROLOGY. 121 

them do, of the general glow so common at sunset which is 
communicated to all objects indifferently, and which ceases 
when the sun leaves them in the shade ; and (3) that the colours 
of clouds analj'sed by a prism by Sir D. Brewster* do not 
appear to be composed as the colours of thin plates are. 

251. Mariotte asserted t that the proper colour of air is 
bhie, just as he considers that of water to be green, and as 
other bodies have peculiar tints. Bouguer revived this doc- 
trine J, and added to it the consideration, that if air reflect 
bine light it may be expected to transmit the complementary 
colour as red (as is stated to be the case with sea-water), and 
hence he explained the fiery colour of the horizontal sun, and 
the tints of sunset. This opinion has been adopted by Euler§, 
Leslie II, and many later writers, but especially by Brandes, 
who, in a most ingenious article in Gehler's Dictionary^, has 
maintained its complete adequacy to the explanation of phae- 
nomena. 

252. This theory must, I think, be considered imperfect 
rather than erroneous. That the colour of pure air by reflexion is 
blue, can, I think, hardly be doubted. But that the explanation 
of the hues of sunset is incomplete, can be doubted by no one 
who is unable to persuade himself, with Brandes, that the dif- 
ference of intensity on different evenings is only an ocular 
deception, or depends on the presence of clouds which receive 
and repeat the colour. 

253. Something more is wanting, then, to the explanation, 
and many acute writers have supposed that some impurity in 
the air produces, by its absorptive action and variable quantity, 
the phsenomena in question ; and several of these authors com- 
pare the effect to that of opalescence in turbid fluids, which 
generally transmit a ruddy beam. Under this head we class 
Honoratus Fabri**, our countryman Thomas Melvillft, De- 
laval|:J, Count Maistre§§, and Sir D. Brewster ||||. Of these 
writers. Count Maistre is the only one who suggests that 
watery vapour, under peculiar mechanical conditions, may be 
the source of the variable atmospheric hues^ " producing an 

* Edinburgh Transactions, xii. 544. Compare EncyclopcRcUa Britannica, 
art. Optics, p. 510. 

t CEmwm, i. 299. Leide, 1717. I Traite d'Optiqite, -p. S65— 8. 

§ Letters, ii. 507. || Encyclopadia Britannica, art. Meteorology. 

1 Art. Abendriithe, vol. i. p. 4. 

** Quoted by Eberhard. Rozier, i. 620. 

t+ Edinburgli Pbysical and Literary Essays, p. 81. 

XX Manchester Memoirs, First Series, ii. 214. 

§§ Bibliotheque Universelle, November, 1832. 

III! Edinburgh Transactions, xii. 530. 



122 REPORT— 1840. 

effect analogous to that of the powder of calcined bones in 
opaline glass*." 

254. I have endeavoured to showf that the colorific property 
of watery vapour may not merely be gathered from induction, 
but demonstrated by direct experiment. Having first noticed 
that high-pressure steam, during a certain stage of condensa- 
tion, is coloured, and transmits orange-red light, I extended 
the observation to steam of low pressure. There seems no 
reason to doubt that the property of vapour, to be coloured in 
passing from its pure, elastic, colourless state to that com- 
monly called vesicular (such as it appears in clouds, or in 
issuing from the spout of a kettle), is a general one, and there- 
fore that great masses of vapour at any temperature under- 
going condensation must pass through the colorific stage. Now 
the development of the brightest atmospheric coloui-s is in- 
variably attended with change of temperature. And Forster, 
without the remotest reference to theorj-, has recorded that the 
sunset glow is contemporaneous icith the dew-point tempera- 
ture ; hence he argues that " some sudden change produced by 
the Jirst falling dew is the cause of the simultaneous change of 
colour in all the clouds then visible J". The application of this 
doctrine to atmospheric colours, as a prognostic of weather, is 
likewise evident and satisfactory §. 

255. Dry Fogs. — Of atmospheric colours, which may be con- 
sidered imusual, the blood-red colour of dry fogs, which have 
occurred at various times over a vast extent of country, is 
amongst the most remarkable. It is hardly possible to believe 
that tiiey are not due to the accidental intermixture of foreign 
matter with the atmosphere. Remarkable fogs of this kind 

• Edinburgh New Philosophical Journal, vol. xv. Count Maistre explains the 
colour of water by similar reasoning. He considers it blue for reflected, and 
yellowish orange for transmitted, light; and tlie green colour of the sea and 
some lakes he attributes to diffused particles which reflect a portion of the 
transmitted tint, and mingle with the blue. This is well confirmed by Davy's 
observations (Salmoiua, third edition, p. 317). Arago has very ingeniously 
applied the same reasoning to the ocean, showing that when calm it must be 
blue, but when ruffled, the waves, acting the part of prisms, refract to the eye 
some of the transmitted light from the interior, and it then appears green 
{Comptes Rendtts, 23rd July, 1838). Most authors have admitted the intrinsic 
blue or green colour of pure water, as Newton (Optics, b. i. part ii. prop. 10), 
Mariotte, and Euler. Humboldt seems doubtful {Voyage, 8vo, ii. 133.). 

f " On the Colour of Steam under certain circumstances." " On the 
Colours of the Atmosphere." — Edinburgh Transactions, xiv. 371 ; Philoso- 
phical Magazine, Third Series, xiv. 121,419; xv. 25; and Poggendoi'ft''s 
Annalen. 

J Researches about Atmospheric Phaenomena, third edition, p. 87. 

§ Those who wish for fuller details on the history of this part of the sub- 
jeet, will find them in my papers above referred to. 



SUPPLKMENTARY REPORT ON METEOROLOGV. 123 

occurred in 1783 and 1831 ; on both occasions they extended 
from Europe to America 5 the fornjer lasted a month, and 
enveloped the highest Alpine summits *. 

256. Blue Sun, — At the latter date (1831) the sim's disc was 
seen of a blue or green colour in the South of Europe and in 
America. This extraordinary phsenomenon we might be dis- 
posed to attribute, with M. Aragof, to an ocular deception 
arising from the intense contrasted orange of the fog, did we 
not find that it has been repeatedly observed under circum- 
stances to which this explanation would perhaps hardly apply. 
M. Babinet, a skilful observer, has seen it twice himself |. He 
accounts for it by Dr. Young's theory of mixed plates, in 
which colour is produced by the interference of two pencils of 
light which have passed through unequal thicknesses of a re- 
tarding medium. This he supposes may be the case in the 
atmosphere by the union of rays " which have passed through 
vesicles of water or vapour with those which have passed 
through air only." Now, though M. Babinet has ingeniously 
imitated the effect by a thin film of mixed air and water placed 
between two glasses, there is some difficulty in conceiving an 
extended medium like the atmosphere, which should present an 
analogous constitution §. 

257. Secondary Sunset Tints. — Many authors have described 
the appearance of a revival of the sunset glow upon the sum- 
mits of lofty mountains long after apparent sunset, and ten or 
fifteen minutes after the tints which accompanied it have dis- 
appeared ||. The appearance in question was once noticed with 
extraordinary effect by the writer of this report, in the case of 
the Jung Frau seen from the profound valley of Lauterbrun- 
nen, from which the sun had so long disappeared that it was 
almost nisjht below, whilst the upper half of the snowy moun- 
tain was illuminated by a delicate but intense red tint, like that 
of a glowing coal. Prof, de la Rive has offered as an explana- 

• Annuaire, 1832, p. 244. f Annuaire, p. 249. 

+ Comptes Rendus, viii. 306. Sir U. Brewster communicated at Glasgow an 
accoimt of this phaenomenon, observed by Dr. Harvey at Bermuda. See 
Atheiiceum, 3rd October, 1840. The appearance referred to occurring on the 
loth August, 1831, is evidently part of the same widely -extended appearance 
quoted by M. Arago in the Annuaire for 1832. Dr. Harvey, however, does 
not appear to have observed the blueness of the sun's disc, but only that of 
objects illuminated by it ; — a circumstance, which, had it stood alone, might pro- 
bably have been accounted for by the doctrine of accidental colours. 

§ The phcsnomenon of the scintillation of the stars has lately engaged the 
attention of M. Arago, who states {Comptes Rendus, 1840) that he has disco- 
vered a complete explanation of it founded on the laws of the interference of 
light. 

II Germ. " Gliihen der Allien.'' See Brandes in Gchler, art. Almosphcire. 



124 REPORT — 1840. 

tion of this phaenomenon *, that it occurs when the air is ex- 
tremely clear and highly charged with humidity (as we should 
expect from (254.)), and that the rays which then reach the 
mountain have undergone total internal reflexion in the higher 
and moister strata of the atmosphere. 

258. Aerial Shadows. — ^We do not by this refer to shadows 
of persons thrown on clouds surrounded by coloured glories, of 
which we will afterwards speak, but of shadows of clouds and 
other objects projected to a great distance in the air, and which 
being rendered visible by its imperfect transparency, produce cer- 
tain remarkable effects of perspective. The diverging rays so 
often seen proceeding from the sun, when near setting, are of this 
kind ; and the corresponding fact of rays (or clear intervals 
between the shadovvs of clouds), which appear to converge to a 
point diametrically opposite to the sun. This rarer phaeno- 
menon we have twice seen ; once, combined with a rainbow, to 
whose centre of course the rays were directed ; and lately, from 
the summit of Goatfell in Arran, whence the rays appeared 
directed to a point in the sea, and converging from all sides of 
the circumference. We chiefly mention the circumstance to 
call attention to a curious and elaborate paper by Professor 
Neckerf, of Geneva, who undertakes to prove that diverging 
solar rays are sometimes produced by very distant mountains, 
and that they thus picture forth, to inhabitants of our country, 
spectral outlines of mountain- cliains in another, far removed 
from direct vision. 

259. Polarization of Sky-light. — Sir D. Brewster appears 
to have been the first to remark that the light of the blue sky 
exhibits traces of polarization J. I apprehend that it must be 
difiicult to assert that the blue rays are actually so polarized, 
for the polarization of the white light, with which no doubt the 
blue is diluted, would produce the effects observed. I do not, 
however, doubt that such is the case. 

260. M. Arago determined the polarizing angle for air to be 
45° nearly §, and the maximum polarization of the sky to be 
90° from the sun's disc, the polarization being in a plane passing 
through the ej^e and the sun. It is a singular fact, and one 
difficult of explanation, that, proceeding to a greater distance 
than 90° (in a vertical plane), the polarization diminishes, be- 
comes zero, and reappears in a plane perpendicular to the 

* British Association, Seventh Report, Sections, p. 10. See too a paper by 
Prof. Necker, of Geneva, Phil. Mag., 3rd series, i. 335. 

■\ Annales de Ckimie, Fev. Mars, 1839, and Bibliotheque Universelle, 
xxiii. 355. 

X Treatise on New Philosophical Instruments, p. 350. Edinburgh, 1813. 

§ Biot, Traitc de Physique, iv. 289. 



STIPPLEMBNTARY REPORT ON METKOROLOGY. 125 

former^. The distance of the neutral point from the sun varies 
with atmospheric contingencies. The position of this neutral 
point seems to have been at first inaccurately reported, for we 
find English observers searching for it in the sun's neighbour- 
hood, and not in the opposite quarter of the skyf. The 
polariscojies of Arago and Savart, used for detecting the 
minutest quantities of polarized light, are little known in this 
country ; it is by their aid that the light of the moon is ascer- 
tained to be slightly polarized. 

261. On the phasnomena of Mirage we have nothing new to 
state. The phaenomena of Twilight and of Atmospherical Re- 
fraction, although connected with Optical Meteorology, we 
shall also omit. 

B. The Rainbow. 

262. There is no step in the progress of science more inter- 
esting than that which calls in the aid of comparatively abs- 
truse principles to explain the slighter outstanding variations 
between theory and observation, which were overlooked in the 
first unqualified satisfaction with which the announcement of a 
simple general principle, harmonizing with every-day experi- 
ence, is invariably received. Amongst such cases may be 
reckoned the law of double refraction in crystals with tivo axes, 
Laplace's correction for the velocity of sound, — and we may 
now add, the phaenomena of the rainbow, so far as these were 
not included in Newton's general explanation. 

263. The diameter of the jt;r??nar?/ rainbow (caused by two 
refractions with one intermediate reflexion), and of the secondary 
(caused by two refractions and two reflexions), may be most 
easily found by the formulae which M. Babinet has lately 
given X for expressing the radii S, directly in terms of the re- 
fractive index of water m, viz. 

T. , • . o S (4 - nrf 

For the primary, sm^— = ^^ ^^^ 

^ , , . S ?>2''+18m^-27 

lor the secondary, sni -7-= 7. — 5 

•"2 8 /«"=*. 

• See Peclet, Traife de Phyalqt/e, 4me edit. art. 1448. I am unable to 
state whei-e M. Arago's original account of these experiments is to be found. 
Compare Quetelet's Notes to Herschel on Light, French Translation, ii. 554. 

t Airy and Chevallier, Philosophical Magazine, N. S., iv. 312, 313. I must 
add, however, that a very recent communication by M. Babinet to the French 
Academy of Sciences (Compfes Rendus, 19th October, 1840) states the exist- 
ence of a second neutral point, 20° or 30° distant from the sun. 

X Comptes Rendus, iv. 646. The demonstration is given in Peclet, 7'raite 
de Physique, 4me edit. art. 1489. 



126 REPORT — 1840. 

4 
Adopting with Newton * the index in ■= — , we obtain 

For the first 42° 2' 

For the second .... 50° 59'. 

264. The comparison of these theoretical angles with obser- 
vation is not so easy as might appear, depending (1) on the 
doubt which i-ay of the red space we are to consider as the last 
visible one in the rainbow, and (2) on the gradual shading off 
depending on the sun's apparent diameter. There is reason to 
think that the measures of tlie rainbow require revision ; but 
we would rather place the fate of the theory upon other grounds. 

265. The first fact which Newton's theory did not embrace, 
was the existence of supernumerary or spurious bows ; tvit/dn 
the Inner, or Primary Rainbow, and without the Outer, or 
Secondary one. These were very accurately described by 
Langwith in 1722 t, — three internal rings of green and purple 
(with traces of a fourth) associated with the primary rainbow. 
The much rarer phaenomenon of the supernumerary exterior bows 
of the secondary rainbow has been noticed by DicquemareJ 
and Brewster §. The supernumeraries have the same order of 
colours as the bows to which they belong, i. e. those within the 
Primary have the Red exteriorly, those without the Secondary 
the Red interiorly. 

266. Pemberton || explained these spurious bows by the 
colours of thin plates ; and at a much later period Venturi ^ 
attempted to account for them by the deviation of the figure of 
falling drops from sphericity. Such fallacious endeavours 
show how cautiously we should receive explanations of such 
phfenomena on the grounds of general plausibility. Tlie true 
explanation had already been given by Dr. Young, who in pur- 
suing his fertile discovery of interference, pointed out its appli- 
cation to the rainbow in a manner so clear**, that it is surprising 
how for thirty years, this, one of its happiest adaptations to 
phaenomena, has been so generally overlooked. 

267- In the ordinary geometrical theory of the primary rain- 

* Optics, book i. part ii. prop. 9. 

f Philosophical Transactions, 1723, quoted by Dr. Young. Dr. Young 
cites Mariotte as the first who mentions supernumerary bows (Chromatics, 
Encyc. Britt.),but without a reference. 

X Quoted by Young, Lectures, vol. ii. p. 316. 

§ Edinburgh Journal of Science, vol. x. p. 1G3. 

II Pliilosopliical Transactions, 1723, quoted by Dr. Young. 

^ Commentari sopra la Sloria et le Teorie dell Oltica. Bologna, 1814. 
Quoted by Dove and Kamtz (Meteor, iii. 165). 

** Phil. Trans. ISOi. Read Nov. 21, 1803. Lectures, vol. i. 470; ii. 316. 



SUPPLEMENTARY RKPORT ON METEOROLOGY. 12/ 

bow, it is well understood that a limit of deviation, due to two 
refractions and one reflexion of the sun's light within the drop 
is a definite and impassible one. The illumination of the bow is 
produced by the accumulation of rays near the limit of maximum 
deviation ; an incidence a little greater or a little less than that 
due to the limit will equally give a smaller deviation ; and as in 
a shower there are assumed to be drops which shall send rays 
to the eye in any given direction consistent with the relative 
position of the observer and the sun, rays more or less approach- 
ing to parallelism (therefore more or less densely luminous) will 
reach the eye from drops placed so as to furnish rays at less 
angles than that of extreme deviation. Confining our attention 
to a single colour (the red, for instance, which is the outermost 
in the primary rainbow), we should expect to find a red bow, 
quite sharply terminated exteriorly, but shading off gradually, 
though pretty rapidly, towards the interior. When we recollect, 
too, that this reflexion within tlie angle of maximum deviation is 
derived from rays which have fallen at a smaller as well as at a 
greater angle of incidence than the critical one, and which 
therefore emerge rigorously parallel, we are surprised at first 
sight that the insulation of the colours in the successive arcs 
should be as great as it appears to be. 

268. The doctrines of physical optics, as laid down by Dr. 
Young, enable us to explain this satisfactorily ; for the very re- 
duplication of the reflected light just alluded to (which a very 
little reflection will show to be derived from opposite halves of 
the drop, separated by the position of critical internal reflexion 
for producing the maximum deviation) reminds us of the funda- 
mental fact of interference, that annihilation as well as increase 
of light may attend the union of rays proceeding in a common 
direction, derived from a common source, but which have tra- 
versed paths of diff'erent lengths. Whilst, then, near the critical 
angle of reflexion the luminiferous waves necessarily reach the 
eye in the same, or nearly the same phase, the rays derived from 
a greater and a less incidence have (though they ultimately 
coincide in direction) described paths whose difference will 
soon amount to half an undulation, when their effects will be 
mutually destructive. Thus by the principle of interference the 
bow of any colour has its interior boundary far more sharply 
defined than if such a cause (which is manifestly modified by 
the size of the drop) had not existed*. 

* See Young's original paper, Pliil. Trans. 1804, where he estimates the pos- 
sible breadth of the diffused zone of light, which otherwise would have shaded 
off from the rainbow, at 25°. 



128 REPORT — 1840. 

269. Thus, bixt for interference, we should have had but a 
feeble and impure rainbow. But further, the same considerations 
explain the supernumerary arcs : for it is evident, from what 
has now been stated, that after destruction of light by opposi- 
tion of phases has been produced, an equal additional retarda- 
tion of the one ray upon the other will produce concurrence of 
phase, and double light ; hence, as in all similar cases, a series of 
luminous bands rapidly diminishing in breadth and h) intensity 
will be formed with more or less vividness, depending upon 
the brilliancy of the reflexion and the separation of the bands 
(which again depends on the size of the drop). The distance 
between the true and spurious bow gives the data (upon prin- 
ciples which will be very readily conceived *) upon which the 
diameter of the drops of rain may be calculated, which Dr. 
Young finds to be between J^th and g^th of an inchf. By similar 
principles it is found that the supernumeraries of the secondary 
bow will be exterior to it and somewhat broader. 

270. The darkness of the space between the primary and 
secondary bows is equally a consequence. of the common theory 
and the corrected one it:. It is dark compared to the spaces 
containing the diffused lights (what Dr. Young calls the double 
lights, or duplicatures) corresponding to the respective bows. 
This darkness was described by Descartes§. The light of the 
primary and secondary bows||, and also of the supernumeraries 
so far as observed^, is polarized in the place of reflexion. 

271. Mr. Airy has recentlj'^ investigated fully the intensity of 
the light in the neighbourhood of a caustic formed by reflexion 

* Viz. for the obsei'ved deviation of the red ray in the spurious bow, find the 
angles of incidence and reflexion within the drop for the two rays which com- 
bine to produce it, and find the diflference of the paths of the rays which corre- 
spond to this in terms of the radius of the drop. Reduce the difference of 
patlis in water to that in air, and equating it to the length of a wave of red light, 
find the radiu> of the drop. Dr. Young has indicated this process in his obscure 
but able and comprehensive article Chromatics, in the Encyclopcedia Britannica, 
with which Mr. Potter, who has recently written in support of Dr. Young's 
views (Camb. Trans, vi. 141), appears not to have been acquainted. 

•f- Pliilosophical Transactions, 1804, and Chromatics. 

X It is, however, very impei-fectly or inaccurately explained in most popular 
treatises. Mr. Ainger has given a very detailed account of it in the Journal 
of the Royal Institution (Feb. 1831), in which he has added nothing material to 
what was shown by Dr. Young ; nor has he adverted to the cause of the super- 
numerary bows. 

§ Brandes, art. Regenhogen, in Gehler, p. 1324. Kamtz, Mefeorologie, iii. 
p. 158. It is very singular that neither of these authors seems to be aware of 
the true theory of the rainbow, or of Dr. Young's writings on the subject. 

II First observed by Biot. See Annales de Chimie, xxxix. 430. 

i[ Arago, jinnales de Chimie, ibid. 



SUPPLEMEXTARY REPORT ON METEOROLOGY. ] 29 

and refraction as in the rainbow*. Computing the intensities 
rigorously on the principles of the undulatory Theory of Light, 
he arrives by laborious numerical computations at the following 
results : — 

1. The boundary of the caustic is not a mathematical line; 
but the light shades off with extreme rapidity. 

2. The radius of the primary bow does not coincide with the 
geometrical caustic deduced by the connnon theory. It lies 
within it at a distance depending on the size of the drops, and 
on the consequent separation of the interference fringes. 

3. To find the radius of the geometrical bow from observation, 
"Add to the radius of the brightest observed bow i^ of the 
distance between it and the first supernumerary bow." 

4. Between the primary and the first supernumerary there is 
a space absolutely dark. 

272. As several of these results differ quantitatively from 
those deducible by the simpler methods of Dr. Young, it is of 
importance to verify them experimentally. For the reasons 
already stated (264.), it is diflicult to obtain satisfactory compa- 
rative measures from the natural rainbow. Much more deli- 
cate observations are obtained by an ingenious experiment de- 
vised by M. Babinet, of allowing a minute stream of water to 
flow through an opening ^^j-th of an inch, or less, in diameter, 
and observing the deviation of rays proceeding from a small 
lumuious bodyf. In this way Professor Miller, of Cambridge, 
has confirmed Mr. Airy's result as to the deviation of the prin- 
cipal bow from the geometrical place of the causticj. 

273. The existence and positions of the supernumerary bows 
and their dependence on the diameter of the refracting cylinder 
of fluid (and likewise on its index of refraction), have been shown 
by M. Babinet himself, who has observed no less than sixteen 
interior, and nine exterior supernumeraries, by means of a 
streamlet of water of the diameter above-mentioned §. 

274. With a comparatively large (y^ths of an inch) cylinder of 
glass he obtained the usual theoretical dimensions of a bow for 
the appropriate index of refraction. The supernumeraries were 
excluded by the size of the cylinders ; but he obtained bows 
caused not only by one and two internal reflexions, but three 
and four, up to seven. These, the ternary, quaternary, &c. 
rainbows have been long theoretically known, though rarely, if 
ever, observed in nature. The ternary rainbow ought to occur 

* Camb. Trans, vi. 379, The abstract in the Phil. Mag., Third Series, vol. 
xu. p. 452, is inaccurate. f Comptes llendus, iv. 647. 

I Phil. Mag., Third Series, vol. xiii. p. 10. This experiment was shown to 
me by Professor Challis. § Comptes Rendus, ut sup. 

VOL. IX. 1840. K 



130 RKPORT — 1840. 

about 41° from the sun, but is generally stated * to be too faint 
to be visible. Two observations by Bergmaini are the only 
recorded ones I have met withf . Kamtz observed a ternary 
bow amidst the spray of the falls of SchaffhausenJ. 

275. We have said that the appearance of supernumerary 
bows indicates the presence of rain-drops below a certain size, 
as well as of considerable uniformity of dimension. It is re- 
markable that Langwith observed, more than a century ago, that 
" this effect depends upon some property which the drops retain 
whilst they are in the upper part of the air, but lose as they 
come lower down and are more mixed with one another." M. 
Arago seems inclined to suppose, on the authority of d'Abbadie 
and the officers of the Venus §, that supernumerary bows are 
rarer in equatorial climates than in ours. It should be recol- 
lected, however, that Bouguer saw them in South America with 
an unusual degree of vividness and separation ||. M. Arago has 
recommended to the Academy of Sciences of Paris the execu- 
tion of a good coloured view of the rainbow, as a guide to ob- 
servers. 

C. Halos% and Parhelia. 

276. The apparent complication of the phaenomena of halos 
and parhelia has given rise to a great deal of vague speculation 
and loose though ingenious theory. Observations of facts have 
been likewise wanting in precision. On these grounds, we 
will endeavour very briefly to discuss that part of the sub- 
ject which seems to have been most successfully dealt with, and 
endeavour to refer the explanations which have been given, to their 
proper authors; for so much has been written on the matter that 
the same thing has been produced as new by various writers at 
different times. 

277- What would first be desirable would be a clear state- 
ment of what is to be considered a complete or normal example 
of the compound display of halos and parhelia. The phaeno- 
menon seen by Hevclius, at Danzig, 20th of February, 16'61**, 
which has generally been considered as a characteristic exam- 
ple, consisted principally of — 

* By Young and Babinet. 

f Abhandlungen der Schwedischen Academie filr 1759, p. 234. Quoted by 
Brandes. + Lehrbuch, iii. 160. 

5 Aimuaire, 1840, p. 305. || Mem. de Paris, 1 757, p. GO, quoted by Kiimtz. 

•[[ The halos now spoken of are the great halos of 22i° and 46° radius, and 
have no reference to the small halos or coronas with which they are often con- 
founded, but which have a distinct origin. 

** Tt is figured in almost every work on the subject. See Huyghens's 
Op- Reliqua, ii. 38, and Fraunhofer in Schumacher's Abhandlungen, Heft iii. 



SUPPLEMENTARY REPORT ON METEOUOLOGY. 131 

(1). Three halos round the *-un, having Radii of 22^°, 46°, 
and 90° nearly. The two smaller circles are generally coloured, 
the red being innermost. The circle of 90° is a rare appear- 
ance *, and is colourless. 

(2). A horizontal circle passing through the sun in which the 
parhelia or mock suns occur, usually at (or rather a little be- 
yond) the points where the halos intersect the horizontal (or 
parhelic) circle, and sometimes also in the point exactly opposite 
to the sun (anthelion). 

(3). Arcs of circles with reversed curvatures, touching the ha- 
los of 22 1^° and 46° at their highest and lowest points. Mock 
suns sometimes appear also in the halos vertically above the 
true sun. 

278. Even more complex phasnomena are occasionally re- 
corded, as that observed at Petersburg, 29th of June, 1790, by 
LoAvitzf. For a history of such appearances we must refer to 
Brandes's article in Gehler's Dictionary, Kamtz's Meteorology, 
the article Meteorology in the Encyclopaedia Metropolitana (with 
an excellent plate), Fraunhofer's paper on the subject J, and to 
Dr. Young's invaluable catalogue of references §. In the mean- 
time we proceed to the theory of the fundamental appearances. 

279. In the 17th century Mariotte referred the halos of 22i° 
to refraction through triangular prisms of ice. Minute icy 
spiculas being conceived to float through the air, or rather to de- 
scend slowly through it in all possible directions, a diffused re- 
fracted light must be seen, as is actually the case when the air 
is in this state ; but those prisms which chance to be in a po- 
sition such as to refi-act the sun's image to the eye in the posi- 
tion of minimum deviation, will (as in the rainbow, where the de- 
viation is a maximum) affect the eye more intensely on account 
of their parallelism and accumulation. The least deviated rays 
(the red) Avill fall upon the eye at the smallest angle with the 
sun, and consequently will form the smaller ring of the halo ||. 

280. Huyghens proposed a different theory^, which for a time 
superseded that of Mariotte. He attributed the phaenomena 
to refraction through spherical and cjdindrical particles of hail 
having opake nuclei of determinate magnitudes. But the ar- 
bitrary nature of his hypothesis is contradicted by the constancy 

* In fact, the observation of Hevelius was unique in this respect until the 
circle of 90° was recently witnessed by Erman (see Poggeiidorff 's Annalen, 
1840, xxxix. 255. note.). 

t Figured by Young (Lectures, i., plate xxix. fig. 433) and by Kamtz. 

X Schumacher's Astron. Alhandlungen, iii. § Lectures, vol. ii. 

II Mariotte, (Euvres, 1686, quoted by Young. 

il Huyghens, Phil. Trans., 1670, and Opera Reliqua, ii. (Young). 

K 2 



132 URPORT — 1840. 

of the radii of the principal halos, which indica^^es a uniformity 
of cause incompatible with Huyghens's assumption. The theory 
of Huyghens is alluded to by Newton, though without any ex- 
press approbation, at the close of his Theory of the Rainbow*; 
and in another part of his Optics f the principle of refraction 
through ice-prisms of 58° or 60° is distinctly stated as the pro- 
bable cause oi halos of 22i°, which appears to have been New- 
ton's own view, as he gives a reason for it (the oval form of some 
halosj), and does not quote Mariotte. 

281. So little reason, then, is there for supporting Huyghens's 
theory on the ground that it was maintained by Newton, as M. 
Biot has done§, even since Mariotte's theory has been revived 
by Young, who published it in the second volume of the Royal 
Institution Joui-nal||, where he states that he had adopted 
the principle before he knew of Mariotte's application of it ; 
and he had even inferred from it that the refractive index of 
ice is less than that of water, a fact then doubted, but after- 
wards confirmed by Dr. Wollaston^. M. Babinet has therefore 
no ground for affirming** that M. Arago was the first to revive 
Mariotte's explanation. 

282. The most obvious facts in support of Mariotte's theory 
of icy prisms are, 

(1). That the imperfect crystals of ice which alone we can 
obtain, have a tendency to rhombohedral crystallization, amongst 
the forms of which are three- and six-sided prisms ; and the 
minimum deviation of light through an ice-prism of 60° would 
give the halo of 22i°. 

(2). The constancy of the effect gives a probability to a con- 
stant cause, such as a crystalline angle. 

(3). The fact that halos occur most frequently in cold cli- 
mates and after a sudden fall of temperature, when the moisture 
of the air is evidently and palpably deposited in icy spiculfe or 
hoar frost. In the excellent observations made in the United 
States, the relation between the sudden fall of the thermometer 
and the occurrence of halos is very clearly tracedff. 

* Optics, book i. part ii. prop. 9. t At the end of the second book. 

J It is rather singular that the same reason which was urged by Newton in 
favour of the theory of refraction by ice-prisms, should be stated by Arago 
{Aniiuaire, 1836, p. 303 ; 1840, p. 303) as an anomaly which, on that theory, 
still requires explanation. It is plain that Newton had some theoretical opinion 
on the subject which he has not explained, and according to which the upper 
radius of the halo should be shorter than the lower. 

§ Traite de Physique, iii. 476. || See his Lectures, ii. 306. 

^ Ibid. ** Comptes Rendus, iv. 639. 

•ff- Annual reports made to the legislature by the Regents of the Universities 
of the State of New York. 



SUPPLEMENTARY REPORT ON METEOROLOGY. 133 

(4). The important fact ascertained by M. Arago, that the 
light of halos is polarized by refraction and not by re- 
flexion*. 

283. But other evidences arise from the application of the 
same principles to the phenomena which accompany the first 
halo, and many of which Mariotte pointed out so clearly as to 
supersede much which has since been written on the subject. 

284. The halo of 46° maybe ascribed to two refractions with 
the minimum deviation tl. rough two successive prisms of 63°, 
or as Cavendisli supposes t, to the refracting angle of 90° formed 
by perpendicular terminations of the ice-prism. Such termina- 
tions, Dr. Young observes, are rather doubtful, and in his later 
writings J he inclines to the doctrine of successive refraction 
through two prisms. Fraunhofer § supposes pyramids with an- 
gles of 88° to be the cause ; and he assigns as an explanation, 
which appears to him perfectly satisfactory, of Hevelius's great 
circle of 90°, the limiting angle of total reflexion in six-sided 
prisms, which is 89° 56'. Hence this circle is white. 

285. Parhelia. — Mariotte accounted for this phcenomenon by 
the preponderance of ice-prisms in a vertical direction (which 
he attributed to their being heavier at one end, — Dr. Young, 
more justly, to the resistance of the air ||), which therefore wi^li 
form a brighter coloured image of the sun when the plane of re- 
fraction is horizontal than in any other plane. Mariotte had 
even the acuteness to see, that as the sun rose above the horizon, 
the plane of refraction being no longer accurately horizontal in 
order to reach the eye, the virtual refracting angle of these ver- 
tical prisms would necessarily be increased, and the deviation 
being greater, the parhelia would statid out beyond the limit of 
the halo, a fact remarkably coinciding with experience. Thus 
an officer of Sir Edward Parry's Expedition T[, observed par- 
helia distant 24° 40' from the sun, the halo being at 22° 30'. 
The parhelia are coloured, the red edge being nearest to the 



sun 



286. The horizontal or parhelic circle is not accounted for 
by Mariotte, because (he says) he had not an accurate descrip- 
tion of it. His commentator. Dr. Young, ascribes the horizon- 

* Bulletin Universel (Ferussac), 1825, Sci. Math. iii. 304. 

t Young, ut supra. 

X See the article Chromatics in the Encyclopaedia Britannica. But the same 
doctrine is stated m his earliest papers, to which nothing of any consequence 
has been added in elucidation of this subject, except M. Arago's important ob- 
servation of the plane of polarization. !'«<." 

§ Schumacher's Ahhandlungen, iii. 77. 

II Journal R. Inst, and Lectures, ii. 307 (1807). 

H Quoted in art. Meteorology, Encyclopaedia Metropolitana, p. *169. 



134 REPORT — 1840. 

tal circle to " the reflexion or even the repeated refraction of 
the vertical facets*", an explanation which seems entirely satis- 
factory ; for though amorphous vertical fibres Avould produce the 
same effect (as Fraunhofer showed), yet it is much more natu- 
ral to ascribe the horizontal circle to the same cause with the 
parhelia which occur within it, and which are, in fact, merely its 
most notable points. Young attributes the mock suns occa- 
sionally observed at an elongation of about 142° to two refrac- 
tions and one reflexion in the same ice crystals f. 

287- Fraunhofer, in his Memoir already cited J, ascribes the 
horizontal circle to the superposition of diffraction- spectra, 
which produce an excessively elongated image of a body viewed 
by reflexion from a striated surface, like that of glass smeared 
with grease, and then cleaned by rubbing it in one direction, 
when a whitish reflexion will take place perpendicular to the 
streaks. A similar view has been given more lately by M. Ba- 
binet§, who compares the horizontal reflexion to that observed 
from fibrous crystals, such as topaz and gypsum. 

288. Contact-arches^. — The only remaining phfenomenon 
which seems fairly accounted for, is that of inverted arcs of lu- 
minous circles touching the halos, usually at their vertical dia- 
meter and accompanied by a parhelion, so that Dr. Young de- 
sci'ibes it as " a bright parhelion immediately over the sun, with 
an appearance of wings or horns diverging upwards from the 
parhelion^." This Dr. Young has ascribed with great inge- 
nuity and probability to very short triangular prisms, which 
from their flatness fall with their axes and refracting edges in 
a horizontal position, so that the plane of refraction is vertical. 
The abundance of such prisms (compared to those which fall 
obliquely and form the halo) give rise to the vertical parhelia 
(which Fraunhofer has, I think very unsatisfactorily, explained 
by difiraction**). Horizontal prisms parallel to the former, 
lying to the right or left of a vertical plane, passing through the 
observer and the sun, will evidently refract the solar image in a 
plane not perpendicular to the axis of the prism (because not 
vertical), and for which the refracting angle being greater, the so- 
lar image (formed always at the angle of minimum deviation,) 
will appear more elevated as the obliquity of refraction is greater, 
that is, as we proceed to the right or left from a line vertically 
above the sun. Dr. Young has cojifirmed his view by actual cal- 
culation ff. 

* Lectures, i. 444. f Chromatics, sect. ii. % P- ST'. 

§ Compies Reiulus ; lU sup. || See art. 277. (3). 

^i Lect. ii. 307. col. i. See the figure of Hevelius's halos, and others. 
** Schumacher, ill supra, p. 78. -f-i- Luct. ii. 308. col. i. 



SUPPLEMENTARY REPORT ON METEOROLOGY. 135 

289. Vertical lines passing through the sun and circles con- 
taining the sun in their circumference have also been described. 
The former seem to be independent of the existence of ice cry- 
stals ; I shall therefore return to them presently. As to the lat- 
ter, we can only state generally, tliat from the wonderful com- 
plication which the figures of crystallized snow and hoar-frost 
take, we can conceive circumstances adapted to almost every 
degree of complication ; and such complication may be aptly 
illustrated by the curious figures which Sir D. Brewster has 
given of the wonderful variety of reflected figures observed at 
the surfaces of disintegrated crystals*. The same ingenious 
philosopher has illustrated the phaenomena of halos by observing 
a distant light thi-ough alum crystallized rapidly on a plate of 
glass f. 

290. M. Galle of the Berlin Observatory has lately published 
an elaborate paper on the subject of halos and parhelia |, in 
which he gives a minute account of those observed by himself 
during nineteen months. Within this time he saw seventy-eight 
halos of 22i° ; of which only two were sensibly elliptical ; and 
he saw no halo of 46°. He afterwards gives at great length a 
general view of the theory of refraction by ice-prisms. 

291. A remarkable parhelic appearance was observed by 
Lambert at Wetzlei-, in 1838, in which there were two hori- 
zontal circles at greater altitudes than the sun, but no?ie passing 
through his disc. Besides the usual lateral parhelia there were 
four others at the points of contact and intersection of the halos 
of 22^°, and 46° with the horizontal circles §. 

D. Coronce : Glories, 8fc. 

292. The coloured rings so frequently seen round the sun 
and moon when thin clouds pass over their discs, are carefully 
to be distinguished from true halos, as they may easily be, by 
the following characteristics, which evidently point to a wholly- 
different origin : — 

• Edin. Trans., vol. xiv. plate x., &c. 

t Edin. Phil. Journal, viii. 394. This experiment, which has probably been 
oftener quoted than repeated, I have more than once attempted without success. 

I ToggendoiS 's J7malen, 1840. xxxix. and 241. 

§ L'lnstitut, No. 321, Fev. 1840. M. Moigno, who quotes this description 
from Poggendorff's Annalen, claims for M. Babinet the theory of the parhelic 
circle and vertical parhelia. These are, however, both due to Young ; the only 
addition which, so far as I know, M. Babinet has made, is the very just remark 
that the horizontal circle will be brighter beyond the first lialo' than within 
it, because in the latter case the illumination is derived from reflexion only, 
by the vertical facete ; in the former from refraction likewise. 



136 REPORT 1840. 

(1). They are much smaller, their radii (when several series 
of their colours appear at once) being from 1° to 6°. 

(2). The radius of any ring is not constant at different times. 

(3). The red occupies the outer ring, instead of the inner one 
as in the true halo. 

293. These coloured rings have a manifest analogy to those 
which bear Nev\i;on's name ; and that great man, in his Optics*, 
has given an explanation, which, translated into modern lan- 
guage, would express the interference of the light reflected 
from the different parts of the drop. In June, 1692, he ob- 
served three rings or orders of colours round the sun of the 
diameters of 5° or 6°, 9° 20' and 12°; on the 19th February, 
1662 (so early had he begun to speculate on these subjects), be 
had observed the two inner coronae round the moon to have di- 
ameters of 3° and 5|°, little more than half the dimensions of 
the others. 

294. The true explanation was unequivocally given by Young 
in 1802, in his paper "On some cases of the production of 
colours not hitherto describedf," amongst the consequences of 
the fertile principle of interferences, though in a different way 
from what Newton had imagined, or Jordan, who had attributed 
these colours to the inflection of light. Young had practically 
shown that the interposition of uniform striae or powder be- 
tween the eye and a luminous object produces coloured images 
of that object, depending for their position upon the dimensions 
of such striae or powder ; and he had theoretically given that 
beautiful explanation which was afterwards put in a more 
popular form by Fresnel and Fraunhofer. Yet it is remarkable, 
that the latter author (Fraunhofer), in describing the experi- 
ments on which he grounds the very same explanation of co- 
ronse, never mentions the name of YoungJ. 

295. The explanation in effect amounts to this, — that on 
the wave-theory of light, a luminous point is seen only in 
one direction, because the diverging wave produced propagates 
from its surface at any moment impulses which, when they 
reach the eye with any sensible obliquity, have their effect 
compensated by the opposite displacements caused by the ad- 
jacent portions of the wave. Bj' the interposition of particles, 
opake or of a certain refractive power, and of nearly uniform 
size, portions of ligiit become sensible in an oblique direction, 
by the stoppage of the other poi'tions whose different length of 
path wovdd have caused them to annihilate the action of the 

* Book ii. part iv. obs. 13. f Philosophical Transactions, 1802. 

\ Entstekung der Hofe kleiner, Art. Schumacher, Astr. AbhandL, iii. 56. 



SUPPLEMBNTARY REPORT ON METEOROLOGY. 137 

first. The angle of obliquity in which any light will reappear 
must depend upon the size of the opake particles ; con- 
sequently, such coloured rings as this cause produces will vary 
with the size of the interposed globules of water or vapour, and 
will generally be larger as these are smaller. This was the 
principle of Dr. Young's Eriometer for measuring the diameter 
of fibres and powders*. Thus Dr. Young has shownf, that a 
Corona, 8° in diameter, corresponds to the existence of drops 
(or spherules of any kind) -^y^j ^" diameter. 

296. As might be expected, this dimension varies with the 
season. It appears, from the careful ohservations and compu- 
tations of Prof. Kamtz:^, that the diameter of the spherules is 
least in Maj^, being then -00054 French inch ; and greatest in 
January, when it is -00107 inch. This is one of the most 
certain data relative to the constitution of clouds. There seems 
no doubt that these are the "Vesicles" observed by Saus- 
sure§. 

297. The successive orders of colours recur at angular di- 
stances, nearly, or exactly, in arithmetical progression from the 
centre II . 

298. Glories. — The well-known phsenomenon of coloured 
rings surrounding the shadow of an observer thrown upon a 
cloud, has an evident analogy with the preceding one ; and up 
to a certain point, the same explanation may apply. But there 
are peculiar difficulties connected with this appearance, which 
seem to be yet imperfectly resolved. 

299. Bouguer observed in South America his shadow thrown 
on a cloud, and surrounded by coloured rings of 5° 20', 11°, and 
17°, and a white ring of 67° in diameter^. Scoresby observed 
at sea a similar phaenomenon on a thin stratum of fog. The 
rings had radii of li° or 2°, 4° 45', 6° 30', and a whitish circle 
extending from 36° 50' to 42°. A larger and still fainter circle 
was once observed**. Professor Kamtz has seen on the Rigi 
similar circles of radius 37° 27' on one occasion, and 42° 10' on 
another, which he considers as true rainbows, very faintly 
tinged with red outside, and with blue within. At the same 

* Described in his Introduction to Medical Literature. 

t Art. Chromatics, Encyc. Britt., Sect. xi. 

X Lehrbuch der Meteorologie, iii. 102. § See above, Art. (218) and note. 

II Young. Compare Herschel on Light, Art. 701. Fraunhofer, quoted by 
Kamtz, iii. 96. Babinet, Comptes Rendus, iv. 643. 

% Memoires deVAcadimie des Sciences, 1744, 4to edit., p. 264. Each man 
saw only his own shadow ; but the reason assigned is not very clear. " Chacun 
de nous vit son ombre projetee dessus (?'. e. on the cloud), et ne voyait que la 
sienne, parceque le nuage n'offroit pas une surface unie." 

** Kiimlz, iii. 108. 



138 REPORT— 1840. 

station I have seen a single compound circle, of which the red 
ring had a diameter of 18°; but when 1 entered the cloud on 
the surface of which it had been formed, it contracted to about 
10°. In the Jura Mountains I once perceived traces of a faint 
ring of from 75° to 80° in diameter.* 

300. Accompanying the coloured rings, there is an appear- 
ance of white light, more intense towards the centre (corre- 
sponding to the prolongation of a line drawn through the sun 
and the eye of the spectator), which would give evidently the 
brightest illumination in the middle point, but for the shadow 
of the observer's head, which, however, is wonderfully di- 
minished by the nebulovis light. 

301. That crystals of ice should have anything to do with 
these appearances, as conjectured by Bouguer and Scoresby, 
is altogether incompatible with the circumstances under which 
other observers have seen them. It is equally impossible to 
refer these rings to the diffraction of the solar light falling 
upon particles of vapour surrounding the observer's head, as 
Fraunhofer supposed fj and reflected back to his eye from the 
surface of the cloud ; for I have observed these rings distinctly 
from a height of fifteen hundred feet above the cloudy screen, 
under a brilliant sky. But the common theory of diffraction of 
particles reflecting as well as stopjmig light, affords a plausible 
account of some of the phsenomena. We have only to suppose 
the constituent materials of the cloud to be spherules (however 
composed) of nearly equal size which reflect innumerable images 
of the sun from their surfaces, backwards to the eye. Some of 
t'lese must be placed at distances which shall re-inforce each 
other's effect, and some which shall annihilate that effect; and 
hence periodic colours will result, as in transmitted light (the 
case of cor once). 

302. This opinion is confirmed (1) by the order of colours 
being that of diffraction rings (the red outermost) ; (2) by the 
arithmetical progression of the diameters observed by Bouguer 
and Scoresby ; (3) by the curious fact noticed by myself, that 
on immersion in the cloud the rings suddenly shrink in size 
(due, no doubt, to an increase in the magnitude of the cloudy 
particles in the interior) ; (4) from the comparison made by 
Professor Kamtz, between the diameter of the Corona by 

* Ha5'garth, in the Manchester Memoirs (1st Series, iii.), gives rather an 
unsatisfactory account of a glory which must have resemhled those seen by 
Bouguer and others. The greatest faint circle at a distance from the smaller 
ones, is distinctly shown in the bad plate which accompanies the paper. 

f Schumacher, Ahhandl., iii. 63. 



SUPPLEMENTARY REPORT Oti METEOROLOGY. 139 

Transmission, and the Corona by Reflexion, the same stratum 
of cloud forming both ; and he obtains in general a satisfactory 
coincidence* ; (5) by the curious observation of M. Babinetf, 
of similar rings formed round the shadow formed on the minute 
particles of gunpowder which had been laid out to dry. 

303. On the other hand, it is not consistent with what we 
know of such phasnomena, that the third ring (for instance), 
that having a diameter of 18'^, should be seen so vividly, and 
sometimes to the exclusion of any other (for it is hardly likely 
that so large a ring should be one of the first or second order). 
The great rings of 67° to 84° in diameter, can scarcely be thus 
explained. 

304. Dr. Young seems to have felt the full difficulty of the 
subject of reflected glories ; and he has unfortvmately expressed 
himself very obscurely upon it. In his earlier writings |, he 
contented himself with referring them to the colours of thin 
plates ; but afterwards he seems to have hesitated whether to 
consider them as modifications of the corona (by diffraction), or 
of the rainbow. In his article, " Chromatics §," he has given 
a singularly perplexed theory, which we have read over many 
times without clearly understanding ; the reasoning, however, 
appears to be this : — Supposing a cloud to be formed of drops of 
water, light, four times reflected within such drops, will furnish 
rays which will unite in the same phase from both sides of the 
drop, at a point diametrically opposite to the sun, whilst rays 
(also four times reflected) ultimately coinciding in direction, 
and which have undergone reflexion at smaller and greater 
angles, will unite in different phases, the retardation being 
nearly as the angular distance from the central point. It is 
to these supernumerary bows of the fourth order, that he ap- 
pears to attribute the inner circles, whose diameters were, in 
the observation of Bouguer, 6°, 11°, and 17°. 

305. Having found the size of the drops which would give, 
by diffraction, rings of this description ||, he proceeds to find the 
distribution of the colours of a primary rainbow formed by such 
excessively minute drops (less than 40^00 inch). He assigns 
to the first supernumerary red bow a radius of 24°, of which, 
however, he makes no use. He then observes, that owing to the 
minute size of the drops, the shading off of the primary colours 
is very slow on the concave side, so that the red will sensibly oc- 
cupy a breadth of 7^°, the violet of 5i° ; and as the red and 

* Meteorologie, iii. 111. f Coviptes Rendus, iv. 645. 

X Lectures, ii. p. 645. col. i. § Encya. Britt., seventh edit., p. 638. col. i. 
II Computed, however, for a radius of 5° for the first ring ; whereas, in 
Bouguer's observation, the diameter was 5* 20'. 



140 REPORT — 1840. 

violet arcs are already 2° apart, they will overlap, and form a 
whitish ring, whose radius will be that of the red ring of the 
rainbow, or 42°, diminished by 7i°j leaving about 35° for the 
radius of the whitish ring, agreeing sufficiently well with ob- 
servation, 

306. I apprehend, however, that there are many difficulties 
in this view of the subject. That light, four times reflected, 
should have intensity enough to produce three or more coronae, 
seems incredible. Again, the ring of 37° to 42° radius, ob- 
served by Kamtz and Scoresby, with faint colours, seems to be 
the rainbow itself, not the superposition of its faded colours, 
for Dr. Young very obscurely hints'* as to the non-appearance 
of the real bow. The reason of its variable magnitude and 
faint colour is quite sufficiently explained by Mr. Airy's in- 
vestigation (271.), in wliich the deviation of the maximum of in- 
tensity from the geometrical caustic is shown to depend upon 
the size of tlie drops, and that diminution of size diminishes the 
radius of the bow, and likewise the sharpness of its definition, 
though in every case (as it seems to us) the maximum next the 
caustic must be most intense, and therefore the true bow can 
never vanish so long as any of its subordinate features remain, 
which Dr. Young seems to have thought possible. Finally, 
Dr. Young, in another section of the paper so often referred 
tot, adopts the theory of diffractitm as producing the lesser 
glories, and calculates the size of the drops on that hypothesis, 
which size is double that obtained on the other. 

307. Had not this discussion been already extended further 
than persons more interested in meteorology than in physical 
optics may think suitable, I should have dwelt at some length 
upon certain curious phsenomena of shadows with luminous 
borders, and certain vertical trains of light seen in connexion 
with them, which seem not to have received the attention which 
their theoretical importance demands. I will state very briefly 
what may serve to instigate further inquiry. 

308. Standing on the tower of Carisbrook Castle with a friend 
one calm hazy summer evening near sunset, I perceived glori- 
fied shadows as from the Rigi, but without colours. So intense 
was the concentration of rays opposite the sun, that the shadow 
of the head of the observer was almost obliterated by the inten- 
sity of the light which seemed to emanate from it. The shadow 
of the body was fringed all round by a luminous but colourless 
border. The shadow of another person standing a short way 

♦ Chromatics, p. 635, col. i. ; p. 638, col. i. 
■\ Chromatics, Sect. xi. 



SUPTLEMENTARY RKPORT ON METEOROLOGY. 141 

off presented to the first observer nothing peculiar. The hniii- 
nous haze extended but a short way right and left, but in a ver- 
tical direction it extended through a very considerable angle, 
producing the very singular effect of a train of hazy light. The 
same effects I have seen less perfectly in other localities, but 
generally towards sunset, and only when a considerable space 
intervened between the observer and his shadow. 

309. Similar phsenomena have been described by various ob- 
servers, and variously accounted for*. The vertical train of 
light which occasionally accompanies halos, has been explained 
by the reflexion from the bases of vertical cxystalsf; but as it 
is seen to occur in circumstances such as those mentioned in the 
last paragraph, it must evidently be independent of the existence 
of ice in the air. Fraunhofer has endeavoured to explain it on 
principles of ditfraction|, and I conceive that it is most likely 
to be explained on some such principle, taking into account the 
abrupt variations of temperature which often take place near 
the ground towards sunset, and which produce strata of air 
very variously charged with moisture in various degrees of con- 
densation, horizontally disposed, and partial reflexion in which 
would undoubtedly tend to produce a diffuse vertical image, such 
as we see on water slightly rippled, when looking across the 
rippled surface. The main cause, however, of this expanded 
vertical image appears to be, that by looking very obliquely 
through a thin stratum of cloudy particles, their apparent di- 
stances will be diminished by the obliquity, and their interstices 
in the same proportion. Diffraction bands will, therefore, ex- 
pand in the direction in which the particles are apparently 
compressed. I have found that such pheenomena are accurately 
reproduced by suftering soap- suds to dry upon a plate of glass, 
and then looking at a flame ohliqnely through it : when viewed 
perpendicularly neither colour nor diffused light appears in one 
direction more than another. 

310. The occurrence of the anthelion itself, or luminous 
point opposite the sun, is not of so easy explanation as some 
writers seem to consider it ; and until it is fully understood, we 
can hardly hope to explain all its modifications. The glory 

* See the observations of Hevelius, Derham and Young, qvioted in Young's 
Lectures, ii. 303, as to the vertical train of light ; more lately by Mr. Christie, 
British Association, 7th Report, Sections, p. 15. [Mr. Christie's original commu- 
nication to the Meeting at Cambridge in 1833, contained in a letter to me, 
appears to have fallen aside, and is neither published nor in my possession.] 

\ First by Young, also by Babinet (^Comptes Rendus,\y, 640), Galle (Pogg. 
xxxix. 256), and others. 

X Schumacher, Jbhandl., iii. 82. 



142 RKPOHT— 1840, 

observed round the head on dewy grass * is evidently referrible 
to the reflexion from spherical drops at no great distance from 
one another. The peculiar luminous fringes observed round 
the ivhole shadow (308.), I have assured myself by many trials 
to arise from no optical deception. There is a space close to 
the shadow, and following its boundary, more luminous than 
the fully eidightened space beyond, — a fact which it seems 
not easy to explain. It appears to have no reference to the 
nature of the body (as, whether it is bedewed or not) which 
yields the shadow ; nor is it altogether dependent on the body 
which acts as the recipient screen, but it depends chiefly, I ap- 
prehend, on the condition of the strata of air very near the 
ground. AVe must consider it, I suppose, as an effect of dif- 
fraction, such as would, in point of fact, be seen where the 
shadow of a body is thrown upon a screen by a single radiant 
point at a certain distance ; in this case, however, it is not the 
smallness of the luminous bodj'^, but the cluster of minute 
globules which reflect small images of the sun that are the cause 
of the difi"raction ; the efi^ect being to produce a luminous band, 
succeeded hy a darker one whose contrast renders it more visi- 
ble. The effect is no doubt enhanced by the indeterminateness 
of the surface which reflects these little images. The shadow 
is seen through the whole depth of the nearly invisible cloud, 
and the bounding surface of light and shade will be most pro- 
minently seen when the eye is in a position to follow its course 
in the interior of the mist. 

311. The phsenomenon described by Professor Neckerf , of the 
intense illumination of shrubs and trees forming the horizon 
behind which the sun has just set, is, I conceive, a precisely 
parallel fact; and M. BabinetJ has explained it in a similar 
manner. But there is still something in this as an optical phse- 
nomenon which seems to me to require further investigation. 

312. It should not be forgotten, with reference to the phaeno- 
mena of clouds, that they have been treated by Young and others 
on the hypothesis of their being composed of spherical droj)s of 
water. Bouguer, Kamtz and Fraunhofer, maintain their vesi- 
cular structure ; and the last-named author has in his Memoir, 
so often cited, considered minutely the course of a ray of light 
through a spherical watery shell. The great modification which 
the common rainbow undergoes in a cloud, and the rarity of its 

* Garthe, Ahhandhing iiber den Heiligenschein : quoted by Kamtz, iii. 106. 
and other authorities there mentioned. 

f Philosophical Magazine, Third Series, i. 332, where two diagrams repre- 
sent the fact very well, as I remember to have seen it under Professor Necker's 
directions. J Comptes Rendus, iv. 644. 



SUPPLEMENTARY REPORT ON METEOROLOGY. 14.3 

occurrence, seems, to say the least, to give some plausibility to 
the latter opinion. 

X. Suggestions. 

313. In conclusion of this report, I propose to offer a few 
suggestions more definite than I have yet given for the advance- 
ment of meteorological science. I have glanced at various ques- 
tions which require elucidation, and which fall within the scope 
of science in its present state ; but a'more systematic recapitula- 
tion of some of these will place them more intelligibly before 
the reader. 

314. It has long been matter of regret, that the labour which 
every one knows is spent on meteorological inquiries, should be 
so ill-directed ; but this it is easier to regret than to remedy. It 
is discouraging to be obliged to declare that meteorological ob- 
servations, to be of any value, are not so easy as is commonly 
supposed, and that not only perseverance but intelligence is 
generally speaking necessary to make such observations as are 
useful to science. Many registers, however well kept and or- 
ganized, are redundant ; many would be useful were the results 
reduced and corrected ; many may have a local value, though 
they do not greatly advance the general progress of science. 

315. For the sake of precision I will combine what I have to 
say under three heads, (1) On Public Observatories, (2) On 
Private Sedentary Observations, (3) Suggestions to Travellers. 

A. Public Observatories. 

316. It is of little use complaining of the past neglect of me- 
teorological observations in astronomical observatories. Some 
attempt is now being made to combine with them a system of 
meteorological observation, or what is better, to institute mag- 
netical, meteorological, and generally, physical observatories. 
The vast sums of money which have been spent in doing over 
again what has been better done elsewhere in determining as- 
tronomical data, might have almost created new sciences of ob- 
servation. 

317. The meteorological observations at Paris deserve par- 
ticular notice, as having been conducted upon a simple and re- 
gular system, for a considerable series of years. The barometer 
and thermometer (which, I believe, are kept in good order) are 
registered four times a day — at 9 a.m., Noon, 3 p.m., 9 p.m., 
hours evidently selected for the barometic oscillation*. At Brus- 
sels the barometer, thermometer, hair hygrometer, wind, and 

* Published in the Annales de Chimie and Comptes Rendus. 



144 RKPORT — 1840. 

state of sky, are registered at 9, Noon, 4, and 9*. At Marseilles 
a very elaborate register is kept every three hours (I believe) of 
the day and night, under the watchful superintendence of M. 
Valzf. At St. Petersburg and other stations of the Russian 
empire, meteorological and magnetical observations are made 
eight times a day — viz. at 8, 10 a.m., No(m, 2, 4, 6, 8, 10 p.m.J 

318. Oljservations are regularly made at the Milanese Ob- 
servatory, Palazzo Brera, at 0, 3, 6, 9, 12, 18, 21 liours astrono- 
mical time, and are published in the Bihlioteca Italiana. We 
learn from an article in the Bihlioth(^que Universelle^, that ex- 
tensive meteorological observations by Sig. Colla, at Parma, are 
published, under the title of Giorniile y4stro)iomico. Farther, 
it appears, that at the late meeting at Pisa, it was agreed, on the 
motion of Sig. Antinori, to concert measures for contemporane- 
ous and comparable observations throiigliout Italy ||. 

319. The observations conducted at the various academies of 
the State of New York, and published annually liy the legislature, 
are still continued on a uniform plan, and must be productive of 
considerable benefit to science. Near tlie equator, at Trevan- 
drum, in the East Indies, an admirable meteorological register is 
kept, under the direction of Mr. Caldecott, astronomer to the 
Rajah of Travancore. During his recent stay in this country, 
Mr. Caldecott has made arra)igements for extending considerably 
the range of his experiments and observations. 

320. The observatories fitted out under the direction of the 
British Government and East India Companj', combine meteor- 
ological with magnetic observations every two hours of the day 
and night^. It is matter of regret (though it is to be hoped the 
regret is a temporary one) that whilst these admirable means of 
observation have been sent to both hemispheres, and to the 
Antipodes,none have been established «^/jome**. I amnot aware 
that there is a meteorological register which can be called au- 
thentic (in respect of the three following qualifications) conduct- 
ed in any part of the British Islands. 

321. The special objects of public observatories would seem 
to be — 

* Published in 4to by M. Quetelet. 

f Unfortunately it is not published. 

J Published under the direction of M. Kupffer. 

§ For August 1840. 

II Atti degli Scienzati Italiani, p. 30. Sig. Cacciatore's observations have 
been already referred to (U). 

^ Forms of Register are prepared by the Royal Society. 

** Since this was written I am glad to learn from Mr. Airy that arrangements 
have been made, by which an authentic Meteorological Register will be com- 
bined with the Astronomical and Magnetical Observations at Greenwich. 



SUPPLKMiiNTARY REPORT ON MKTKOROLOQY. 145 

(1). To furnish standards of comparison ; 

(2). To establish the laws of phaenomena ; 

(3). To fix secular, or normal data. 
The second of these determinations may be made without the 
first and third, and conversely ; just as in magnetism one set of 
instruments serve to measure variations of elements, which yet 
are incapable of establishing the fundamental values of the ele- 
ments themselves. 

322. In respect to the First point, the instruments must not 
only be originally good, but they must be preserved in constant 
repair, — a matter requiring perpetual revision in the case of 
meteorology. Access, under due regulation, should be permit- 
ted to instrument makers and observers to have their instruments 
compared with the standards*. That the instruments be ahso- 
lutely as well as relatively correct^ is evidently essential to the 
determination of the mean pressure at the level of the seat, the 
actual state of climate \vith respect to temperature, &c. 

323. Secondly. — Thelaws of phsenomena can usually be only 
made out by extended and minute observation, incompatible, 
generally speaking, with private research. Laws of a certain de- 
gree of generality have commonly a pretty wide domination, even 
in a science apparently so capricious as meteorology. The in- 
stance we have mentioned of the "homonymous hours" (37.), 
representing the mean temperature of the day, is one of the kind : 
the constancy of the interval between the hours of mean tempe- 
rature is another : the mean of diurnal extremes being nearly 
the mean temperature of the day is a third : the nearly coincident 
hours of diurnal barometric variation is another : — these, and 
such laws deduced from sufficient data, clear the way for indi- 
vidual exertion, and indeed form the only basis for really useful 
efforts of the kind. A very small number of observatories 
(comparatively), perhaps three or four in the extent of the Bri- 
tish islands, would be sufficient to supply these important data. 
The observations must be made ei-ery two hours at least, for 
with less than this the diuriuil curve could not be properly drawn. 
But such laborious observations would not require to be indefi- 
nitely continued. Once place the meteorological observations on 
a proper footing, by ten, or perhaps twenty years^ observation of 
this kind, and the great difficulty is overcome : there is not a 
chance of sec?//ar changes sensibly aff"ecting these laws; once 
established, they are like the laws of the solar system. 

* As is done, for instance, at Paris. 

t The specific gravity of the mercury sliould be actually ascertained, and the 
pressure might be stated in the corresponding height of a column of distilled 
water at a fixed temperature. 

1840. L 



146 REPORT 1840. 

324. Directions would thus be obtained for prosecuting, under 
the most favourable circumstances, and at the least possible ex- 
pense of labour, all inquiries as to local climate in observatories 
of the second class, and by private individuals. In such ob- 
servatories, observations might be made twice or thrice a-day, 
and some even seldomer. The regular observations at public 
observatories should include the following : — 

Thermometer, barometer and moistened bulb hygrometer, 

at least every second hour. 
Wind may be registered by Whewell's and Osier's gauges. 
The state of the sky may be frequently noted. 
Rain by Osier's gauge ; other rain-gauges at three vertical 

stations. 
Temperature of the earth from the surface down to twenty- 
four French feet. The shorter thermometers must be ob- 
served at different hours of the day ; the longest once a 
week. 
Temperature of the earth at a considerable depth in caverns, 
wells, or Artesian bores. The thermometers (generally) 
should have their zero verified from time to time (twice a 
year). 
Solar radiation by the actinometer. 
Nocturnal radiation. 

Atmospheric electricity and the aurora borealis, with cor- 
responding magnetic observations. 
Falling stars, especially in August and November. Other 

occasional phaenomena, of course, will be recorded. 
Experiments, by means of balloons, on the decrement of 
temperature above the soil. 

325. It would not be too much to expect that the directors 
of the first class of observatories should be capable of forming a 
judgement on the great cosmical questions of meteorology (ad- 
verted to in the section of this report on terrestrial tempera- 
ture,) and of uniting theoretical and practical knowledge to the 
important end of obtaining tangible and useful solutions of 
these great problems. For this purpose, it would be necessary 
not only to institute observations, but experiments ; and, by 
the trial of many independent plans, to estimate the confidence 
due to the various methods in so delicate a research. By ascer- 
taining exactly \\\\?ii data may be obtained a posteriori, a definite 
problem may then be given to mathematicians to resolve; and we 
shall then know, and not till then, what investigations are to be 
regarded as merely speculative, and what of any substantive value. 

326. Thirdly/. — The laws of pheenomena being known by such 
a limited course of elaborate experiment as has been recom- 



SUPPLBMENTARY REPORT ON METKOROLOGY. 147 

mended, the next business connected with a public observa- 
tory is to furnish the secular constants of meteorology, such as 
the mean annual temperature, the mean annual pressure at the 
level of the sea, the limits of variation of these, the mean ela- 
sticity of vapour, the mean and total quantity of sunshine, the 
mean direction and integral quantity of wind, and. similar 
facts, for a given jjlace at a given time. These observa- 
tions are of a less elaborate kind than the preceding ; but the 
fate of all volunteer exjierrments shows, that to determine such 
quantities with minute precision, is incompatible with any but 
an official system of registration, which shall be conducted for 
very many years on exactly the same system, with instruments 
of the same kind, with unremitting attention not onlj' to the 
fidelity of the observations, but to the jierfect repair and com- 
parability of the instruments. Even should such a system not 
be started on the very best possible plan, it is better that it 
should continue uniform, than undergo perpetual change. If the 
hours or locality be not the best possible, the diurnal laws being- 
known, the result of any hour may be converted into a mean 
result ; and as to locality, it is much more important to preserve 
the consistency of results, than to avoid trifling disadvantages. 

327. We have seen that it requires very many years' observa- 
tions to ascertain the mean climateric state of any point of the 
earth's sui-face. In this country, for no one such point probably 
is it accurately known. Let the instruments be the simplest, but 
the best ; the observations, however few, perfectly regular ; and 
we have a certainty that we are laying up valuable facts at least 
for another generation, if not for the present one. 

328. Instead of labouring to collect a multiplicity of imper- 
fect registers, let us begin by laying the foundation of a rational 
and accurate science. If we can but determine accurately the 
secular elements of pressure and tempei'ature at a hundred well- 
chosen points of the earth's surface, we shall do more than has 
ever yet been done to draw a proper system of isothermal and 
isobarometric lines, which shall hand down to posterity the 
actual mean condition of our globe. 

329. Observations must not only be made, but they must be 
wholly reduced and printed, like the astronomical observations 
conducted by Mr. Airy*. They must be ready to be applied to 
the purposes of science, and synoptic tables of results widely 
distributed. In the deduction of Laws from Results, much use- 
less labour may be spared (and the remark is especially appli- 
cable to private observers), by employing graphical projections 

* For this purpose excellent printed forms have been supplied to the Ant- 
arctic expedition. 

l2 



148 REPORT— 1840. 

instead of elaborate formulae of interpolation, a method which, 
however valuable in itself, has been carried to excess by the 
German meteorologists ; and the immense labour they have 
spent in computing arbitrary constants might, in many cases, 
have been better bestowed. Anything, however, is better than 
no reduction at all. The engraving of such charts is well worth 
dohig ; they often afford a check upon the accuracy of the ob- 
servation, the value of the method, and the consistency of the 
results, which no other mode of exhibition can possibly do. 

330. I would notice the projection of observations on sub- 
terranean temperature (96), as a signal instance of all the 
advantages which I have mentioned. Where several simul- 
taneous but independent observations are made, the comparison, 
by projection, gives a moral certainty of the fidelity of the ob- 
servations, whilst the coincidence of one year's observations 
with another demonstrates the confidence due to the method of 
investigation even more satisfactorily than the coincidence of 
final results. Even in point of accuracy, the maxima and 
minima cannot be so well determined by a parabolic interpola- 
tion (as M. Quetelet has done), because the temperature-curves 
invariably rise faster than they fall ; consequently, the oscu- 
lating parabola has not its axis vertical, but inclined to the left 
upwards ; and if a series of circular functions be used to ex- 
press the observations, the computation becomes very laborious, 
and perhaps the result is not more accurate than may be ob- 
tained in a few minutes in the following way. — A thin stiff 
wire may, by a little practi<-e, be adapted so as to follow, in 
a remarkable manner, the sinuosities of the temperature-curves : 
by changing its form by pinching, then bending it elastically, 
and varying the inclination of its symmetric axis with the verti- 
cal, it is easy to lay it so over the curve*, as to satisfy the eye 
that the inequalities on each side compensate one another. 

331. Until national observatories shall be formed, it seems of 
great consequence that the Plymouth Hourly Observations, 
made at the expense of the Association, should hy no means 
be discontinued; that the results, amply reduced, perhaps the 
detailed observations, should be printed at their expense ; and 
most particularly, that the condition of the instruments shall 
be from time to time verified with the utmost care, in order to 
render these determinations positively as well as relatively ac- 
curate, for which I do not know whether there is at present 
any suflicient security. 

• Or polygon; for in all cases, the actual points of observation should be joined 
by straight lines. This suggestion I owe to Mr. Babbage, and I have found it 
attended with great advantage. 



SUPPLEMENTARY REPORT ON METEOROLOGY. 149 

B. Sedentary Observations. 

332. Private individuals, fond of science, would find the 
establishment of such systematic observatories as we have 
recommended, to add great importance as well as interest to 
their labours. 

333. Their business would then be like that of detailed sur- 
veying after the great net-work of triangulation has been com- 
pleted. The local meteorology of a country is often of great 
practical as well as scientific importance, and the immense dif- 
ference of climate frequently experienced within a few miles, 
whilst it shows the embarrassing effect of local causes, and the 
danger of drawing general conclusions from insulated or im- 
perfect registers, is itself a curious subject of research. 

334. Ordinary thermometrical and barometrical registers may 
be continued, as haa been usual, with additional attention to 
the construction and repair of instruments, the choice of situa- 
tion, and the choice of hours. In respect of the latter, 9 a.m. 
and 9 p.m. are very convenient and fitting hours for thermo- 
metric observations, to which may be added 3 or 4 p.m. for the 
sake of the barometric oscillation. But it is one advantage of 
systematic observation, such as was recommended in the last 
section, that it will render available observations made else- 
where at any hour or hours by a general principle of reduction 
to the mean*. Self-registering instruments (thermometers, 
rain-gauges, anemometers, and the like) are well adapted for 
private observation from the little superintendence they require. 

335. I would, however, particularly urge the propriety of not 
confining individual efforts to the mere multiplication of simple 
registers. The same expenditure of time and money is appli- 
cable to much more interesting purposes. Special series of 
observations and experiments on one or more subjects, such as 
the following, would be of very great interest indeed : — 

1. The temperature of the soil at small depths. If the dif- 
ficulty of procuring long thermometers be an objection, 
water-bottles may be lowered to different depths in sepa- 
rate tubes of wood sunk in a well, which is then filled up 
with earth or sand, and the temperature may be noted by 
a common thermometer on pulling them up, the opening 
of the tubes being well stuffed with hay or woolf. (98.) 

* As was clearly pointed out by Sir D. Brewster, in discussing the Leith hourly 
observations. It must be remembered that such reductions are correct only 
within the limits of the region or climate for which they have been ascertained. 

t A not unimportant modification of these experiments might be made by 
covering a certain space of the surface of the soil in which the thermometers 
were sunk, with a composition of ascertained radiating and absorptive power. 



150 BKPORT 1840. 

2. Temperature of mines, galleries, deep wells, overflowing 
or Artesian wells, rivers at various distances from their 
source and from glaciers ; the sea and lakes at difl'erent 
depths and seasons. 

3. Modifications of temperature, + or — immediately above 
the surface of the soil at different hours and seasons. (60.) 

4. Decrement of temperature at different heights, and the 
modification of the annual and diurnal curves due to ele- 
vation. (51, 57.) 

5. A comparison of the different instruments for measuring 
solar radiation — Leslie's, Cumming's, Herschel's, Pou- 
illet's. (61, &c.) 

6. Observations on nocturnal radiation in different states 
of the atmosphere, and towards different regions of the 
heavens (at the same angular elevation) ; comparison of 
the ethrioscope (especially the effect of metallic reflectors 
in increasing cold, questioned by Pouillet) ; Pouillet's 
actinometer ; the thermo-multiplier. (79, 80, 114.) 

7. The ascertainment, by barometric measurement, of the 
elevation of a number of marlied points in the neighbour- 
hood of the observer's residence. A combination of such 
local results would give the general configuration of a 
country. The levelling (by the barometer) of the course 
of rivers, and a few of the most elevated points of the in- 
tervening mountain-chains, is most useful*. 

8. The relation of the boiling points of fluids, especially 
water and alcohol, to the barometer, and the supposed 
anomalies mentioned by Hugi. (163.) 

9. The curious anomalies in barometric measurements de- 
pending on the difference of temperature of the two 
stations (Lenz and Galle), and perhaps on the direction of 
the wind. (159.) This is an important, and, in a favourable 
situation, not a difficult inquiry f. 

10. Further comparisons of the dew-point and moist- bulb 
hygrometer are not necessary. But careful observations 
with the latter are highly desirable under all possible cir- 
cumstances. The curves of annual and daily dryness 
ought to be investigated, and the indications of the instru- 
ment reduced, not by the computation of the corresjiond- 
ing dew-point, but by ascertaining (from Apjohn's for- 

* See M. Guevin's very interesting Mesiires Barometriques dans les Alpes 
Fran^aises, Avignon, 1829. An excellent specimen of what is here intended 
is to be found in the Comte de RafTetot's barometric measurements in the 
valley of Bareges. See Edinburgh Philosophical Journal, January, 1837. 

t Ramond's Memoires stir la Fornude Baromefrique cited in the former Re- 
port may be consulted with advantage on this subject. 



SUPPLEMENTARV REPORT ON METKOHOLOGY. 151 

mula, (175, 180)), the absolute and relative dryness of the 
air, i.e. the tension of vapour and the ratio to saturation. 
Experiments would still be desirable to ascertain the effect 
of a current of air in modifying the indications of the 
moistened thermometer. 

11. To pursue experiments on rain-gauges at three stations 
vertically above one another, (221) combined with hy- 
grometric observations. 

12. To deduce from phgenomena proofs of the revolving or 
radiating character of storms, or of the existence of both 
kinds*. (212, &c.) 

13. To multiply observations upon meteors, especially in 
August and November. For this purpose, nothing more 
is requisite than the combination of several intelligent 
observers, who should select particular portions of the 
heavens for observation, having acquired, by the aid of 
a globe or planisphere a sufficient knowledge of the con- 
stellations, and who, being each provided with chro- 
nometers, should note, (1) the time of appearance; (2) 
the duration of the meteor; (3) its magnitude and phy- 
sical peculiarities ; (4) its direction and velocity of motion. 

14. From what has been said on the subject of atmospheric 
electricity, it will appear that almost everything remains 
to be done on that subject ; he who proposes to enter on 
the field must be prepared to cope with the difficulties of 
original investigation. 

15. Auroral phasnomena. The division of them into classes 
(if possible), of which probably the height, nature, and 
magnetic effects may be veiy different. 

16. Many of the departments of optical meteorology are well 
fitted for Sedentary Observation. See the particulars spe- 
cified in the next section. 

C. Travelling Observations. 

336. A traveller is placed in circumstances so eminently fa- 
vourable for arriving at just conclusions in meteorology and other 
similarly-conditioned sciences, that he cannot be too frequently 
reminded of the responsibility which attaches to his situation. 
All men who have cultivated the valuable art of viewing intel- 
ligently what passes around them, may arrive at important de- 
ductions from the observations of the most monotonous and most 

• Observations of great value may be very simply made by noting the 
periods of sudden rise of wind, and especially the times when its direction 
changes most rapidhj, and the nature of the change. Barometrical observations 
add to the value of these recorded facts. 



152 BtPORT — 1840. 

sedentary life ; but he whose choice or opportunity carries him 
through many climates and varying circumstances, cannot too 
zealously watch the occasion of discovering processes which 
only a happy accident may reveal, and of profiting by the com- 
parison and contrast of phtenomena. Every one knows how 
indolence and indifference steal upon the mind long habituated 
to a daily-shifting scene, and how apt opportunities are to be 
lost through weariness or inattention. The traveller would do 
well, therefore, to entertain some preliminary considerations as 
to the sort of observation suited to his peculiar position. Sy- 
stematic observations are, to a great extent, bej'ond his reach ; 
and regular meteorological journals, kept from day to day under 
continually varying circumstances, are of much less value than 
those made in one spot, so that such registers may very gene- 
rally be abandoned, unless in the case of visiting peculiar or 
little-known climates, where any sort of approximation to sj^- 
stematic observation is valuable. 

.S37- There are, however, certain phaenomena which afford 
such definite conclusions within the range of a few or even of 
single observations, as ought especially to engage the traveller's 
attention ; such, for instance, as 

1. The temperature of the superficial soil between the 
tropics, which, as already stated (128, note), is generally 
constant at one foot deep, and represents the annual mean. 
Intimately connected with this is the important general 
question whether the superficial earth temperature coincides 
generally with that of the air, which is yet undecided. 

2. The temperature of springs, deep wells, andmines. (1 17j&c.) 
The elevation of these above the sea should be determined 
barometrically or otherwise. Where several springs rise 
near one another, the temperature of several should be 
recorded. It does not by any means follow, that the 
largest springs always give the best results. 

3. Particular attention should be paid to those springs which 
appear to have a temperature above or below that of the 
air at the place. In the case of very hot springs it is very 
interesting to repeat the observation with the same ther- 
mometer or instruments which have been compared, in 
different seasons and years*. (131.) 

• Having been requested some j'ears ago to draw up instructions for obser- 
ving springs, I may, in the hope of attracting additional attention to the subject, 
introduce them here, not having been elsewhere published. 

HINTS FOR OBSERVATIONS OF THE TEMPERATURE OF HOT SPRINGS. 

The thermometer used in fixing the temperatures should be originally good, 
and should besides have its freezing point verified occasionally by plunging it in 
melting snow. Fractions of degrees should be estimated at least to one-fourth, 



SUrPLEMENTARY REPORT ON METEOROLOGY. 153 

4. Meteorological extremes have always a certain interest 
which makes them worthy of preservation, whether they be 

if practicable, to one-tenth. If possible one person should note the results at 
the instant that the other observes, and to avoid errors the observers should 
then change places. The stem of the thermometer should be immersed in the 
water, so that the whole mercun'al column may be of the same temperature ; it 
should be kept there until the reading becomes quite stationary, and the read- 
ing made whilst so immersed. 

Hot springs are either uniuclosed, or applied to the supply of baths, &c. 
In the former case great care must be taken in marking distinctly the locality, 
as springs often occur so near to one another that confusion readily arises : the 
hearings of any permanent objects near should be given, ?ir\d.t\\e popvlar name 
of the spring, if it have one. If the spring be collected (as is usually the case) 
from a number of imperceptible sources, the fact should be mentioned and 
the hottest part taken. In the case of the supply of baths, too great care in 
reaching the real sources cannot be enjoined. The servants of the baths are 
often ignorant of the true springs, and are unable or unwilling (because they 
are difficult of access) to point them out. When the real source cannot be 
reached (from being underground or built up) the nearest bath cock should be 
tried, having been first opened for some time, and the observer should record 
the number of the cock, its distance from the spring, and the nature of the con- 
duit, as well as give an eye-sketch of their relative positions. Where the wa- 
ter is stopped in its passage by reservoirs, these .should be especially noticed, as 
they render the observation of temperature of little value. Often the spring 
rises over a great extent of surface into a \a.\gG piscina or public bath. In this 
case the observation is generally unsatisfactory, but the temperature of different 
points of the basin should be ascertained and the hottest recorded. If gas rises 
it should be ascertained whether its temperature differs from that of the water. 
The traveller should repeat his experiment on different days and at different 
hours, and at as great an interval of time as his stay permits. As many springs 
as possible (of those which ai'e really independent) should be observed, and to 
prevent mistakes as to the independence and purity of the springs (for those 
more esteemed are often mixed \\'\\h others of inferior quality) the best author- 
ity (usually the resident physician) should at once be consulted. With a view 
to comparison with former observers, changes in the management of the reser- 
voirs, &c., should be inquired for, and their date noticed. 

No ordinary traveller can undertake an analysis of mineral water, but if the 
spring be employed medicinally he may probably obtain some information 
from the resident physician or druggist, which should be preserved (with the 
authority). He may furthei-, after a little experience, judge (by taste and smell) 
to what class of springs it is referible, as sulphureous, alkaline, saline, chaly- 
beate or acidulous. The easier experiments which he might further make 
would relate to the specific gravity of the water, and to the natiue of the gas 
evolved, which is a very important question. There are cases in which it might 
be desirable to preserve, well corked, a portion of the water for analysis, but such 
are comparatively rare. 

Historical and other information may often be got from physicians and in- 
telligent proprietors of baths. Such persons might sometimes be induced to 
undertake observations every week or month on the precise variations of 
temperature to which a spring is subject. Almost any thermometer would suf- 
fice for this purpose, as only small variations are wanted, and the absolute error 
might be found by comparison with the traveller's standard. But in all cases 
the authority for every statement not directly verifed by the traveller himself 
ought to be distinctly given. 



154 REPORT — 1840. 

of atmospheric temperature, solar radiation, pressure, hu- 
midity, fall of rain, force of wind, or electric tension. 

5. Daily observations of the barometer are valuable, especially 
in tropical regions, because there the calculation of heights 
may at once be completely made without corresponding 
observations. By these means a traveller's route across a 
tract of country may be traced in section, and the value of 
many of his local remarks greatly increased. 

6. Observations continued even for a few days in the equa- 
torial parts of the globe, suffice to determine approximately 
the diurnal barometric fluctuation. (152, &c.) The hours 
seem to be everywhere nearly the same. 

7. Optical meteorological phsenoniena of all kinds admit of 
being peculiarly well studied, from the varying points of 
view in which the traveller is placed. The diameters of 
rainbows, halos and coronee, observed with due accuracy, 
Sind the abnormal phenomena which occasionally accom- 
pany these appearances, are facts of which as yet we pos- 
sess but a slender stock. We may specify the following 
subjects of inquiry: — 

(a.) The colours of the sky, their optical composition, and 
connection with the hygrometric state of the air. (254.) 

(Z».) The polarization of the clear sky, (observed with Sa- 
vart's polariscope) the position of the neutral points, its 
variations, and the cause of the inversion of the plane of 
polarization. (260.) 

(c.) The diameter of the rainbow, and contemporaneous 
measures of the distance of the supernumerary bows from 
the primary. The distance between the Primary and 
Secondary rainbow, measured from the brightest part of 
the Red. [This last is an easy and important observa- 
tion, especially if accompanied with a measure of the di- 
stance of the red of the first supernumerary bow from 
the primary red.] (264, 271.) 

{d.) The diameters (in different directions) of the Great 
Halos, (2S0) ; the condition with respect to polariza- 
tion of the parhelic circle, and other rarer appearances. 

(e.) The phsenomena of glorified shadoivs, (298, &c.) in all 
their particulars ; and the state of polarization of the suc- 
cessive rings. To compare the diameters of the direct 
coronse and those by reflection formed in the same cloud, 
338. The traveller on lofty mountains possesses peculiar faci- 
lities for the following kinds of observation : — 

8. The decrement of temperature in the atmosphere. (51.) 

9. The force of solar and nocturnal radiation at different 



SUPPLEMENTARY REPORT ON METEOROLOGY. 155 

heights. The effect of atmospheric radiation in the day- 
time, in clear and in cloudy weather. (72.) 

10. The impi-ovement of the theory and practice of baro- 
metric measurements, 

11. The dryness of the higher strata of the atmosphere. (190.) 

12. The formation of clouds, their s^mc^we and tempera- 
ture (this last point is one of very considerable interest, 
viz. to compare the temperature of the air within a cloud 
with that of the comparatively dry surromiding air). 

13. The formation of storms, especially thunder-storms, and 
the origin of hail. Perhaps no mountains in Europe are 
so well adapted for these observations as the middle and 
western Pyrenees. 

339. Besides these and similar observations which experience 
will suggest, the traveller may often do something in the way 
of recommending local researches to intelligent persons situated 
on the spot. He may at once afford them the knoivledge (which 
is all that many require) how to make their efforts useful, — the 
stimulus to exertion by undertaking to turn their labours to 
good account, — and the means by providing them with simple 
instruments, or by comparing their instruments with his own. 



Addition to Article 125. 
A paper by Dr. Richardson on the frozen soil of North Ame- 
rica appears in Prof. Jameson's Journal, Jan. 1841. 

Addition to Article 195, on Wind. 
Since this was written, Mr. Osier presented at the Meeting 
of the British Association at Glasgow, perfectly satisfactory 
proof of the close connection which subsists between the diur- 
nal curve of Temperature and the Force of the Wind. The same 
analogy appears to have been made out by Mr. Rutherford, at 
Kingussie, in Inverness-shire (who has been engaged in hourly 
observations under the direction of Sir D. Brewster), although, 
not having an anemometei-, he has been unable to give to it the 
precision of a law, as Mr. Osier has done. 



ERRATA. 
Page 39, 2 lines from bottom, /or instrmnents wadT instructions. 

44, first line of note, /or animal read annual. 

137, line 9,/or 23^5 »'^«^ 2TO3' ^^^^- 



CONTENTS 

OF THE 

SUPPLEMENTARY REPORT ON METEOROLOGY. 

Art. Page 

1 Introduction 37 

Works of Reference. 

15 L Temperature 42 

23 A. Thermometers 46 

34 B. Atmospheric Temperature 50 

45 C. Isothermal Lines 55 

51 D. Decrease of Temperature with Height 57 

61 E. Radiation 60 

81 F. Proper Temperature of the Globe and of Space . . 66 
88, Solar Heat; 110, Atmospheric Heat; 114, 
Temperature of Space ; 117, Proper Heat of the 
Earth ; 129, Springs. 
n. Atmospheric Pressure. 

132 A. Barometers 85 

144 B. Mean Height of the Barometer 88 

151 C. Barometric Oscillations 90 

157 D. Barometric Variation with Height 92 

HL Humidity. 

164 A. Hygrometers 95 

189 B. Distribution of Vapour in the Atmosphere 101 

192 IV. Wind .. 102 

197 A. Anemometers 103 

201 B. Phsenomena of Wind generally 104 

212 C. Phsenomena of Storms 109 

218 V. Clouds— Rain Ill 

233 VI. Atmospherical Electricity 116 

235 VIL Meteors 117 

247 VIIL Aurora Borealis 120 

IX. Optical Meteorology. 

248 A. Colour of the Sky and Clouds 120 

255, Dry Fogs ; 256, Blue Sun ; 257, Secondary 
Sunset Tints ; 258, Aerial Shadows ; 259, Polar- 
ization of Sky-light. 

262 B. The Rainbow 125 

276 C. Halos and Parhelia 130 

292 D. Coronse, Glories, &c 135 

313 X. Suggestions 143 

316 A. Public Observatories 143 

332 B. Sedentary Observations 149 

336 C. Travelling Observations 151 



157 



Report on Professor JVhewelV s Anemometer, now in Operation 
at Plymouth. By Mr. Snow Harris, F.R.S., 8§c. 

[With a Plate.] 

Any one who has at all considered the nature and object of 
Whevvell's Anemometer will readily admit of how great value 
to Meteorology the results of its indications must prove ; — since 
they put us in possession of a sort of figurative delineation of 
the total amount of the aerial current in any direction ; and fi- 
nally enable us to arrive at what Mr. Whewell has not unaptly 
termed an annual type of the winds for any given place : — by 
comparing the types of different places with each other, the 
general annual movement of the atmosphere may be in some 
degree ascertained. 

The want of an instrument which could figure at once the di- 
rection and proportionate velocity of a given current, so as to 
obtain an integral result, has been long felt in Meteorology. 
Common anemometers merely register the time of a given wind 
from a certain point, and leave its velocity out of the question ; 
and although others of a more improved kind register also its 
pressure on a given area, yet there are none, so far as I know, 
which give the complete and truly valuable result obtained from 
Mr. Whewell's, viz. the total quantity or integi*al effect of the 
wind at a given place. 

Impressed with the great importance of such a result to Me- 
teorology, I have frequently, since the Anemometer was entrusted 
to mj' care, given attention to the difficulties in its practical 
working, and have endeavoured to render it more easily ma- 
nageable by ordinary observers. The objections hitherto made 
to the use of this machine are not altogether without founda- 
tion. They principally apply to the difficulty of obtaining in- 
struments which may be taken as sufficiently comparable ; to 
the want of constancy in the operation of the same instrument, 
owing to deterioration in the wheel-work from various causes ] 
to the liability of the machine to become damaged in storms ; 
and to the difficulty of repair. 

Mr. Southwood, who attended to the Register of the instru- 
ment for some time, and who communicated the results at the 
Meeting of the Association held at Liverpool, in 1837, made seve- 
ral valuable improvements in its construction. We have not until 



158 REPORT — 1840. 

very recently succeeded in correcting the defects attendant on 
the working of the machine geiierall3\ 

The recent improvements, in effecting which the sum of 10/. 
granted by the Association at its hist Meeting at Birmingham 
has been expended, I now propose to describe ; and as no par- 
ticular description of the Anemometer by drawings has ever yet 
appeared in the Reports of tlie Association, it may not be amiss 
to give an account of the whole as it now works, since I cannot 
but think it entitled to considerable attention, and that it must 
eventually come into general use in Meteorology. 

For the carrying on these recent improvements, the scien- 
tific woi"ld is indebted to Mr. Kerr of this town, on whose house 
the machine is now at work, and who has kindly undertaken to 
attend to the Register. 

Plate I. AAA, tigs. 1 and 2. — is a circular metallic plate, move- 
able about an axis D, by the action of the wind on a vane V, fig. 
2. A small windmill fly W, formed of brass planes and turned at 
an angle of 5 degrees with a plane perpendicular to the direction 
of the wind is fixed on this plate. The fly revolves by the action 
of the wind, against which it is kept by the vane V, and gives 
motion to an endless screw a ; this screw operating on a verti- 
cal wheel b gives motion to a horizontal wheel rf, through the 
intervention of a second endless screw, not seen in the figure, 
and placed on its axis. This last wheel c is placed at the ex- 
tremity of a long vertical axis M, figs. 1 and 2, upon this is cut 
the thread of a fine screw carrying a nut M, figs. 3 and 10. 
The nut M supports a pencil p, figs. 10 and 3, which acts by 
means of a balance weight q against a fixed cylindrical barrel 
D, fig. 3. The vertical axis of the plate A moves by the action 
of the wind on the vane V through the centre of this barrel, as 
in fig. 1, and thus l)y the revolution of the fly, and the action of 
the vane in turning rovmd the plate, the pencil is caused to de- 
scend and trace a line on various parts of the cylinder D, fig. 3. 
There are 16 vertical lines painted on the barrel, corresponding 
to 16 points of the compass, as in figs. 3 and 12; hence, whilst the 
vane V by turning the plate A causes the pencil to apply itself 
to that line coincident with the direction of the wind, the wind- 
mill W causes it to descend and trace a line proportionate to 
its velocity for a given time — the motion of the fly being by the 
toothed wheels and screws fig. 1, so reduced, that for 10,000 
revolutions, the pencil only descends g^*^^ ^^ '^" inch. The 
barrel D is varnished white, and readily receives the trace of the 
pencil in a thick irregular line, the middle of which indicates 
the mean direction and velocity of the wind. 

When the pencil has descended to the bottom, it must be 



ON MR. WHEWBLL S ANEMOMETER. 159 

again replaced at the top and the Register recommenced. The 
vane V consists of tvvo inclined planes as seen in figure 1, and 
is placed so as to be nearly in the prolongation of the axis of the 
fly. This arrangement has been found to preserve the direction 
more completely and maintain the position of the fly in direct 
opposition to the current. The wheel-work just described is 
effectually defended from wet and other atmospheric damage 
by means of a close cover C, fig. 4, fitted securely and closely 
over it. 

In the instrument hitherto in use, the registering apparatus 
D, fig. 3, is placed within a small wood cover and the whole 
exposed to the wind on the ridge of a house or other elevated 
place. We have found it, however, necessary to set the whole 
up in a more commodious and permanent manner. A small 
lantern of wood about 3 feet square and 4 feet high, within 
which the registering apparatus is placed, fig. 3, has been 
erected on the top of a house, the circular plate A A in figs. 1 
and 2, being moveable over its svimmit and toward which it con- 
verges. The vane and fly are thus freely exposed to the wind 
whilst the registering apparatus descends within. 

In order to sustain the vertical axis upon which the plate A 
turns, a small beam BB, figs. 3 and 6, is placed across the 
bottom of the chamber hollowed at E, fig. 3, in a half circle. 
The hollowed part E carries an iron ring R, figs. 3, 6 and 12, of 
about 4 inches diameter fixed to the beam B by three arms. 
Within this is a second ring of brass r, fig. 6, forming the nut 
of a third ring H, fig. 7 and 12, which can be screwed within the 
former and removed at pleasure bj'' means of a small forked lever 
L, fig. 8. These rings preserve the position of the register 
barrel D, fig. 3, and admit of the easy motion of the axis of 
the plate A in the following way : — the lower extremity of the 
barrel terminates in a solid cap of brass 1 1 1, figs. 3 and 5 ; 
this cap t fits within the rings R r, fig. 6, and there is a stud 
of brass s, fig. 5, projecting from it corresponding to a notch r, 
fig. 6, in the fixed ring ; the position of the lines on the barrel 
indicating the direction of the wind is hence determined. The 
barrel D, fig. 3, is passed up through the ring R on the descend- 
ing vertical axis of the plate D, figs. 2 and 9, until its solid ring 
1 1, fig. 3, comes in place. It is then finally secured by screw- 
ing up the fixing ring H, figs. 7 and 12. When the barrel is 
thus secured, a screw N, figs. 3 and 5, carrying on its extremity a 
polished centre, is screwed up through the bottom of the brass cap 
of the barrel until it reaches the point of the vertical axis D, fig. 
9, of the metallic plate A A, figs. 1 and 2. It is then finally 
secured by a small nut N, figs.'s and 12, turned up with press- 
ure against the under part of the cylinder so as to prevent 



IGO HE PORT — 1810. 

any shake. The pencil and descending nut in fig. .3 work about 
this fixed barrel by means of two supports E H, figs. 2, 3 
and 9 attached above to the under part of the plate A, and 
below to a horizontal clasp of brass P P, figs. S and 9. The 
clasp freely encircles the barrel when closed, and has small 
friction wheels W W W, fig. 9, inserted in it ; the extremity 
or point of the screw M, figs. 3 and 9. moved by the wind- 
mill, turns upon this clasp, as at P, fig. 9 : this clasp is 
shown in this figure open, by means of the joints at P P. This 
arrangement enables the observer when the pencil has descended 
for any given time, to remove the fixed barrel D and substitute 
a similar one, on which the register is continued, whilst that 
just removed is read off and transferred at the observer's leisure 
and convenience. The process of tabulation becomes in this 
way a very simple affair. The removal of the barrel and re- 
placing of the pencil at the top of the scale is easily effected. 
The nut N, figs. 3 and 5, is first removed and the screw within 
withdrawn ; the brass ring H, fig. 7? is then unscrewed by 
inserting the points of the bent lever L, fig. 8, into the small 
holes of the ring seen in figs. 7? 3, and 12. Finally the barrel 
is withdrawn from off the axis and another substituted as al- 
ready described. 

The mechanism of the pencil is represented in fig. 10. In this 
figure M represents the nut traversing the screw S S. This nut 
is made in two parts and is held together by a steadying pin t( 
and a clamp screw C. One of the standards of support E, tigs. 
3 and 10, passes between this clasp and the steadying pin, by 
which the pencil is faithfully steadied in the course of its de- 
scent along the cylinder. There is a small projecting arm n on 
one side of the nut, to which is attached by means of a centre 
pin a curved piece o ; this piece is moveable about the pin car- 
rying within the curve a small knob of brass v set within the 
curve on an axis a. The pencil p and balance weight q are 
attached to this knob v, and thus the pencil is gently pressed 
against the cylinder as shown in fig. 3. The lower part of the 
thread of the vertical rod s on which the nut travels is left 
plain and smaller than the screw above, as seen at P, fig. 9, in 
order to allow the nut to fall freely off; hence if the instrument 
has run out at any time before attention is again given to it, da- 
mage to the fly and wheel work above, by the resistance which 
would otherwise ensue, is prevented. When the barrel has been 
replaced we have merely to turn back the screw C, fig. 10, and 
run the whole up to the head of the cylinder : again clamp the 
imt, and the Anemometer continues to register on the barrel as 
before. 

In order to measure and transfer the amount of wind, there is 



ON MR. whewbll's anemometjsr. 161 

a scale fig. 11, graduated into tenths of an inch, and termina- 
ting in a concave rest G, adapted to the register barrel ; this 
scale is applied accurately along the barrel on which the pencil 
has registered the amount of wind, as shown in fig. 12. There 
are two sliding-pieces j^ P on this scale ; these are set so as to 
inclose the amount of wind in any given direction and the re- 
sult read off on the scale. This may be also easily effected by a 
fine pair of compasses and a common scale. 

The cover C, fig. 4, is so contrived as to be easily removed at 
any time, being fixed on the plate A by four small studs and a 
clamp screw ; a small trap in the roof enables the observer to 
inspect the wheel-work frequently, and occasionally apply a little 
oil to the pivots. The action of the machine is hence preserved 
in a sufficiently uniform state ; and I have little doubt that 
the velocity of revolution of the fly may be fairly assumed as 
proportional to that of the wind. The cover C has been found 
to give the wheel-work the required protection, and the instru- 
ment now in operation here is preserved so as to be quite con- 
sistent with itself. It would not be at all difficult to construct 
anemometers, which if attended to in this way would prove very 
comparable with each other, especially if they were all made by 
the same person, or according to the same proportions in every 
respect; and if the respective rates of motion under the same cur- 
rent were compared at first with a standard instrument, a fair 
degree of accuracy must unavoidably be arrived at. The diffi- 
culties in this respect are not greater than those incidental to any 
other machine in which the effects of wheel- work and friction have 
to be considered, as for instance in the rates of different chrono- 
meters. If the diftereiit pivots were set in agates, and the point 
of the steel axis of the fly allowed to turn against an agate 
instead of bearing upon a shoulder, the instruments would main- 
tain a very uniform action. 

This valuable instrument being now effectively at work, I trust 
at the next Meeting of the Association, to have completed a 
graphical delineation of the integral amount of wind at this place 
for a whole year without any intermission. 

The sum voted by the Association for the purposes of Osier's 
Anemometer has been applied in completing the repairs and al- 
terations found requisite ; in the expense of tabulating the re- 
sults both of the instrument here and at Birmingham ; and to 
other expenses incidental to the observations now in progress. 
Mr. Osier will be prepared to lay some of the results before the 
Physical Section of the Association. 

The remaining sum entrusted to my care for carrying on the 
original hourly series of Meteorological Observations here, has 

VOL. IX. 1840. M 



162 



REPORT — 1840. 



been applied as usual in defraying the expense incurred on ac- 
count of the Hourly Register of the Barometer, Thermometer, 
&c. I have included the results of these Registers for the year 
1839 in my last Report. 

Plymouth, September 10th, 1840. 



* 



16-3 



Report on " The Motions and Sounds of the Heart." By the 
London Committee of the British Association, for 1839-40. 

The following Report consists of two distinct portions ; the 
former consisting of experiments performed at King's College, 
in 1839, by the London Committee for 1838-9; and the latter 
detailing the experiments of the Committee for 1839-403 per- 
formed at the Marylebone Infirmary in the present year. The 
former series, performed in conjunction by Prof. Todd, Dr. 
C. J. B. Wilhams and the Reporter, with occasional assist- 
ance from Dr, Roget, were commenced but not completed, 
owing to the difficulty of procuring subjects and other circum- 
stances beyond the control of the Committee. No report of 
those experiments was consequently presented at the Bir- 
mingham meeting, or has yet been published ; and an account 
of them is therefore now prefixed to the report of the proceed- 
ings of the Committee for the current year. 

The experiments of 1838-9 were performed with the view 
to determine the physical and pathological causes of certain 
modifications of the motions and sounds of the heart that are 
presented by disease ; a chief object being to ascertain how, 
by mechanical and other irritations and by displacement of the 
heart, murmurs could be produced ; how also by inflammation. 
Whether for example, the pericarditic friction sounds de- 
pend on deficient lubrication of the pericardium, or on vascu- 
lar turgescence, or are dependent solely on the effusion of 
lymph ; — how far also the natural sounds might be impaired by 
interrupting the action of the valves in the living subject, or by 
spontaneous or artificially excited abnormal action in the mus- 
cular parts of the cavities without structural lesion. Another 
inquiry was this — How far do the motions and sounds of the 
heart in the lower animals correspond with those of the hu- 
man subject; whether for example, in birds and other animals 
that diflPer more or less from man in their cardiac anatomy, 
there be not corresponding differences in the cardiac sounds 
and motions ? To these questions the experiments for 1838-9 
supply answers in most cases, which are satisfactory in the 
opinion of the Committee to as great an extent as could be 
calculated on from so limited a number of observations : they 
feel however that the experiments were too few finally to 
decide any point of much difficulty or importance, and that 



164 REPORT — 1840. 

further trials under more favourable circumstances are very 
desirable. The experiments referred to are the following : — 

London Committee. — Experiments for 1838-39. 
Observation I. 

June 14th. — Present, Doctors Roget, Todd, Williams and 
Clend inning. 

Subject, an Ass, about three months old. Pulse about 60, 
regular. At 8 o'clock a.m. a long fine needle with a silver ca- 
nula was passed into the chest, at the left margin of the ster- 
num between the ribs to the depth of two inches. The needle 
exhibited motions corresponding to those of the heart. The 
needle was withdrawn, and aqua ammonias diluted with four 
or five parts of water was injected through the canula. The 
pulsations of heart became immediately weak and very irre- 
gular with intermissions. 

10 o'clock. Heart's action natural. Pulse 77. 

12 o'clock. Pulse 70, occasionally irregularly accelerated 
for a few beats. 

2 P.M. Still no abnormal sounds. 

5 p.m. Pulse 78. 

June 15th, 7 A.i\i. Pulse about 80. 

At half-past 7, half an ounce more of solution of ammonia 
was injected as before, after which pulsations weak and irre- 
gular at first, but afterwards regular. Pulse 96, strong, with 
clear sounds. 

12 o'clock. Pulse 72. Sounds natural and regular ; first 
sound somewhat prolonged, with suspicion of murmur. 

June 16th. Sounds strong. Pulse 56. Canula introduced 
at the root of the xiphoid cartilage into the pericardium. 
Some blood followed the needle. Then some strong solution of 
salt was injected ; whence irregular accelerated action of the 
heart. 

4 P.M. No murmur present. Both sounds distinct. Inter- 
mission every fourth or fifth beat (Cg.). 

5 P.M. Pulse irregular. First sound double ; generally in 
triplets, followed by intermission. The second sound being 
absent in the weak strokes preceding the intermission but di- 
stinct and loud at other times. Pulse 56, but variable (Wms.). 

June 17th, 3 p.m. Pulse 56. Still occasionally retarded. 
Both sounds now rough ; roughness most apparent about the 
base of the left side, and scarcely audible in the carotids 
(W. & T.). 

June 18th, 7 a.m. Dead; but yet warm. Much blood 



ON THE MOTIONS AND SOUNDS OF THE HEART. 165 

escaped from subclavian vein on opening chest, and coagulated 
afterwards. A mass of greenish-yellov? lymph in the media- 
stinum. The cellular membrane highly vascular and easily torn. 
Flakes of lymph on lower anterior left lung. External pericar- 
dium marked with many straight vessels, and intermediate red 
striae giving bright redness to the whole. Same in a slight 
degree on the interior of the pericardium, which contained two 
ounces of yellow serum. At base of heart most redness. Cel- 
lular substance here somewhat infiltrated with serum ; whole 
interior of surface of heart healthy, except some slight thick- 
ening and opacity of the mitral valve. A wound plugged with 
lymph found on the anterior face of right ventricle. 

Observation II. 

June 19th. — Subject, an Ass ten weeks old. Pulse 48, re- 
gular and pi-etty strong. Animal weak. By pressing between 
the fingers and thumb the cardiac region, the thumb being on 
the third rib and left side, a loud blowing was excited with the 
first sound, which ceased on removing the pressure. After se- 
veral repetitions of this experiment a short filing sound heard 
(by two members of the Committee) after the second sound, 
the first being clear. On repeating the pressure more strongly 
two murmurs were heard (by the same observers), one with the 
first sound and continuing after it, and one with the second 
sound (which was also weakened) and continuing after it. 

After being fifteen minutes at liberty, the animal had a deep- 
toned blowing with the first sound, which soon ceased, but the 
murmur after the second sound continued. 

June 20th, 8 a.m. Some murmur or filing after the second 
sound as before. A long needle was passed two inches and a 
half deep vertically to the fourth rib along the upper margin 
three inches fi'om the sternum. A strong double motion was 
given to the needle, and a blowing, resembling a cooing, accom- 
panied the first sound. The heart's action was increased 
though the animal seemed faint. 

June 21st. Pulse 60. The needle again introduced three 
inches. As before, the needle presented rhythmical movements 
sternad and dorsad ; that dorsad being slow and forcible, and 
synchronous with the first sound ; that sternad being sudden, 
like a fall back from gravitation, and accompanying the second 
sound. A murmur of a blowing or whistling kind heard with 
the systole and diastole also, the latter variously described by 
different observers. Murmurs and sounds were variously al- 
tered and impaired by pressing the needle flat in different di- 
rections ; on withdrawing the needle, murmurs were heard with 



166 REPORT — 1840. 

systole and diastole, described as rasping and filing, respect- 
ively (W. and T.), the natural sounds being distinct. The 
needle was introduced a second and third time ; after the third 
withdrawal of the needle a loud creaking was heard with both 
sounds by two obsei'vers, but no constant abnormal sound by 
the third ; the creaking was reported (W. & T.) to continue 
some minutes, when the natural sounds returned, with only a 
slight murmur with the second sound. 

June 22nd. Animal dead, (7 a.m.) and cold. Considerable 
effusion of bloody serum in right pleura and mediastinum ; 
some ecchymoses and marks of perforation on left ventricle, 
with corresponding mai'ks and changes on the pericardium. 
Perforation three quarters of an inch below, and behind or 
nearer to the apex than the semilunar valves. The needle had 
transfixed the left ventricle, slightly wounding the mitral, and 
penetrating the posterior wall. The anterior lamina of the 
mitral had ecchymoses, and the posterior lamina was perforated 
near the edge, with a small fibrinous excrescence on the valve. 
The wound passed through the opposite posterior wall of left 
ventricle, around which there was ecchymosis under the peri- 
cardium. 

The aortics were healthy. 

Observation III. 

June 23rd. — Subject, an Ass ten weeks old. Half-past 7 
A.M. Pulse 60 ; strong and distinct. A canula was introduced 
about an inch from the xiphoid cartilage and for about an inch 
in depth, when a sound, first as of rubbing, afterwards as of 
blowing, accompanied the latter part of the systole ; about an 
ounce of strong brine was then injected, when the pulsations 
became tumultuous and irregular, and the sounds obscure, 
with loud gurgling (probably from injection of air). 

3 P.M. Sounds obscure, but more distinct towards the base, 
where a short creaking (Wms. and Tdd.) or blowing (Cg.) ac- 
companied the first sound, which was not audible in the arte- 
ries. Pulse irregular. 

June 24th, 3 p.m. Pulse 90, and regular. Sounds more di- 
stinct than yestei'day ; and towards the base of the heart, 
accompanied by leather or parchment sound. Respiration la- 
borious. Tender near the heart ; but eats well and is lively. 

June 25th, 7 a.m. A loud parchment rubbing murmur with 
each of the sounds, which otherwise were distinct and natural. 
Pulse 80. 

8 a.m. Jugular vein opened. Copious haemorrhage. Heart's 
action became rapid, with slight rubbing sound ; soon however 



ON THE MOTIONS AND SOUNDS OF THE HEART. 167 

became slow and strong, with superficial loud grating or rough 
sound ; and becoming gradually weaker, soon ceased. One 
ounce of serum in left pleura. Two to three ounces in pericar- 
dium. External pericardium exhibited several striated patches 
of minute vessels. The cellular tissue was infiltrated with se- 
rum, and the serous membrane was easily detached. No lymph 
on the inner surface of the pericardium, but the heart was 
completely coated with thin membraniform soft lymph, thick- 
est at the septum, and near the base. On the anterior and po- 
sterior surfaces numerous minute depressions or lacuna? were 
seen in the lymph. The lymph was easily removed. On the left 
ventricle near the apex was an oval space of an inch by an inch 
and a half, of bright red patches, seeming partly vascular, 
partly ecchymotic, about the middle of which was a punctured 
wound and a clot in the muscular tissue beneath, and some 
ecchymoses under the corresponding endocardium. The in- 
terior of the heart healthy. The serum from the pericardium 
after standing separated into crassamentum and liquid. 

Observation IV. 

June 23rd. — Subject, a stout Ass two months old. Pulse 
60-70 ; strong, with sounds very loud. 

Quarter to 4 p.m. A needle was introduced at the upper 
edge of the fourth rib, three inches from the sternum, and one 
inch deep. The heart's action was accelerated, with obscure 
blowing with the systole. 

The needle being withdrawn, the heart's action was slower, 
with double creaking or leather sound, reported by two obser- 
vers as accompanying both sounds, which became stronger after 
a few minutes. Heart's action varying in regularity. 

Quarter of an hour after. Leather sound at the site of the 
puncture, not at all at the apex. Natural sounds there quite 
distinct. 

June 25th, 7 a.m. Both cardiac sounds loud, with sounds of 
friction at the basis cordis. 

June 26th, 7 a.m. Normal cardiac and friction sounds as 
before. A long needle three times introduced in different di- 
rections between the third and fourth ribs, and three to four 
inches from the sternum, without any marked effect, except 
sometimes on strongly depressing the handle towards the ster- 
num, a blowing with first sound was heard, the second sounds 
being normal (rubbing rather than blowing sound, Cg.). 

On first introducing the needle a scratching noise was some- 
times heard with the systole, as if from the point hitching 
against the heart's surfaces. 



168 REPORT — 1840. 

A fine curved tenaculum about two inches in the curve, was 
passed two to three inches from the sternum, behind the third 
rib, with the point toward the spine ; and when at the greatest 
depth, the handle was depressed toward the sternum, so as 
to move the hook outwards toward the ribs ; a loud blowing 
then attended the first sound, which was distinct ; the second 
sound was wanting, when the handle was most depressed, and 
obscure when the handle was somewhat raised, and restored to 
full force when the hook was withdrawn. 

Half an hour after. The first sound was accompanied with 
blowing between the first and third ribs, while a friction sound 
accompanied the second sound (the Reporter called it alto- 
gether //7C#zow sound, with both systole and diastole, but vary- 
ing in hoarseness or roughness) ; it was faintly audible in the 
carotids. 

Half-past 3 P.M. Still slight friction and blowing (roughness 
only of friction. Reporter) increased after the animal struggled. 
The tenaculum was again introduced and manipulated as before; 
and again the second sound was stopped by drawing at the 
root of the arteries, and restored on releasing the hold ; the first 
sound being accompanied by a loud whizzing, and the hoarse 
or rubbing sound being indistinct if not absent. 

On withdrawing the hook, a transitory crackhng was heard ; 
on the introduction of the hook, the heart's action became tu- 
multuous and irregular, and on withdrawing it, very rapid. 
Pulse 112. Half-an-hour after, the pulse still 112, and the first 
sound accompanied by murmur. 

June 27th, quarter-past 7 a.m. Sounds as before; rough mur- 
mur as of friction, with first sound especially. The animal then 
pithed, and artificial breathing established and chest opened. 
Heart was acting vigorously, with the sounds distinct and 
normal. 

First Experiment. 

On introduchig a finger into the right auri-ventricular ori- 
fice, first sound was accompanied with a whizz, and wanted its 
flap at the beginning ; the whizz was accompanied by a thrill 
sensible to the finger introduced ; the whizz ceased and the 
systo:ic flap returned on removing the finger. 

This experiment was repeated several times with the like 
results. 

Second Experiment. 

The hook was introduced through the auricle with a view to 
hook up the tendons of the mitral valves, when the flap seemed 
impaired not suppressed, and the whizz was uncertain. 



ON THE MOTIONS AND SOUNDS OF THE HEART. 169 

Third Experiment. 

A finger placed on the auri-ventricular opening externally 
experienced in the systole the same vibratory or jerking motion 
as would in diastole be felt over the aortics ; and to the eye the 
same motion was visible in the former during the first sound 
at its commencement, as at the arterial openings during the 
second sound (CgO. 

Fourth Experiment. 

A blunt bistoury was introduced into the auri-ventricular 
opening through the auricle, and the tendons of the septal la- 
mina of the mitral were cut partially, when \h.G.jlap of the first 
sound was impaired but not destroyed. 

On examining the heart were found several marks of perfo- 
ration of the large arteries, anteriorly to the valves, and perfo- 
rations just at the opening of the coronary artery, but no valve 
was wounded. There were ecchymoses at the external mouths 
of the perforations, and attached to one wound was a clot with a 
fibrinous peduncle. On the surface of the right ventricle cor- 
responding to the infundibulum, the pericardium was injected 
and roughened by lymph, with several scratches and punc- 
tures ; the lymph was small in quantity and granular in appear- 
ance. A wound in the septum was plugged with lymph, as were 
all the flesh wounds in the interior of the heart. 

Observation V. 

June 29th. — Subject, a Donkey three months old. Half- 
past 7 A.M. Heart's action quite normal. A tenaculum passed 
four inches from the sternum between the third and fourth 
ribs ; the handle having been lowered toward the spine, there 
was a whizzing heard with the first sound ; but the second 
sound was only a little weakened. 

The whizz or blowing contined after the experiment with 
the systole, and after the flap of the valves ; but soon became 
intermittent, and gradually disappeared. 

June 30th. A fine canula was passed through the sternum 
an inch from the xiphoid cartilage, and about twelve ounces of 
warm water were injected ; the cardiac sounds became pre- 
sently apparently distant, especially toward the sternum ; on 
withdrawing the tube, the sounds were still distant with little 
impulse, but were otherwise normal, except that occasionally 
the systole was acompanied by blowing during embarrassed 
respiration. A tumour formed under the integuments of the 
sternum, through which the cardiac sounds were very faintly 
.heard, and without impulse. 



170 REPORT— 1840. 

Heart's action much accelerated. 

July 4th. Animal pithed, and artificial breathing established. 
The experiments on the mitral valves then repeated. The left 
auricle was inverted by the finger and the valves impeded or 
kept asunder by thefinger, in the auri-ventricular opening, when 
various murmurs accompanied or followed the first sound ; the 
second sound being simply either much weakened or sup- 
pressed ; and the normal sounds returned on the withdrawal 
of the finger. This experiment was often repeated with similar 
results. 

A finger being placed on the exterior circumference of the 
mitral and aortic valves respectively at the same moment, simi- 
lar jerking motions perceived in each ; at the closing of the 
valves and evolutions of the two cardiac sounds, the finger, 
when in the auri-ventricular opening, was sensible of something 
like flapping, pushing and tension, as it were, in and by the 
valves, and the supposed edge of the valve was felt tense in 
systole; and, if divided by the point of the finger, the edges of 
the opposite valves were thought to give a feeling of resistance 
such as valvular tension must cause, supposing such tension to 
occur. The first sound was protracted and dull, wanting the 
sharply defined beginning such as a flap would give when the 
valvular action was interrupted by the finger. The first sound 
was obscure, but audible on extraction of the heart, when the 
organ was irritated to contraction. 

Observation VI. 

July 3rd. — Subject, a Turtle, weight 150 lbs. No distinct 
pulsation could be heard externally. After decapitation and 
removal of the callipee the heart was felt by one of the Com- 
mittee, pulsating regularly, and two distinct sounds were 
heard (Wms.), with an interval between ; the heart ceased 
beating too soon to allow of the other member of the Com- 
mittee (Cg.) making any satisfactory observation. 

Observation VII. 

Comparative Observation. 

The observations of the Committee on the motions and 
sounds of the Heart had been previously made almost ex- 
clusively on donkeys and dogs, animals whose cardiac struc- 
ture and modes of action are generally known to agree with 
those of the human subject. It was therefore thought very 
desirable to extend their observations more widely over the 
scale, as by such means it was thought some useful generaliza- 
tion might be obtained, and the views of the Committee be at 






ON THE MOTIONS AND SOUNDS OF THE HEART. 171 

the same time subjected to a new and interesting test, and, if 
sound, fully confirmed, but if defective, corrected ; and in any 
event, that their future conclusions would be based on a 
greater variety of facts and a more comprehensive induction. 
The Committee therefore made arrangements for the purpose 
of visiting the Zoological Gardens, and examining as many of 
the animals there as could easily be approached by strangers 
for the purposes of auscultation, &c. Before visiting the 
gardens, the Committee met at the Hunterian Museum, for 
the purpose of inspecting the preparations illustrative of the 
physiology of the heai't that exist in that national collection, 
and were obligingly assisted in their search by Mr. Owen, 
Professor of Compai-ative Anatomy to the Royal College of 
Surgeons. With the aid of the anatomical data collected at 
the Royal College of Surgeons, the Committee there entered 
at once on their examination of the living animals. Before 
stating any pai'ticulars of our obsei'vations, it is proper to say 
that, in our examination of the wilder animals, we were much 
indebted to Mr. Youatt, the distinguished veterinary surgeon 
of the establishment, without whose kind assistance it would 
have been out of our power even to have attempted anything 
in several instances. Even with Mr. Youatt's aid, we found 
it extremely difficult, in many cases, to make satisfactory ob- 
servations ; so that, in but a portion of the subjects was it 
found practicable for the whole of the Committee to verify 
results to their satisfaction. 

The animals sufficiently examined by all are distinguished 
in the following enumeration : — They are, 

1. The Ostrich. 

2. The Ourang-Outang. 

3. The Leopard. 

4. The Seal. 

5. The Balearic Ci-ane. 

6. The Common Crane. 

7. The Brahmin Bull. 

8. The Puma. 

9. The Indian Antelope. 

Other animals examined to the satisfaction of some mem- 
bers of the Committee, were — 

10. The Elephant. 

11. The Dromedary. 

12. The Antelope. 

13. The Water Buffalo. 

14. The Giraffe. 



172 REPORT — 1840. 

15. The Lion. 

16. The Nylghau. 

17. The Wapiti Deer. 

18. The Hygena. 

In No. 1 (the Ostrich). The pulse at the heart was very 
vigorous, and about 60 in the minute. The systolic, or first 
sound, was long and obtuse : and the second, or diastolic sound, 
was short, and rather obtuse. 

In No. 2 (the Ourang-Outang). The pulse was quick, and 
the cardiac sounds and rhythm like those of the heart of a 
child very exactly. 

In No. 3 (the Leopard). The pulse was 60. The first sound 
normal, but the second rather indistinct, as compared with 
the human standard. 

In No. 4 (the Seal). Pulse not materially different from 
the human. First sound long and obtuse, second sound short 
and clear. 

In No. 5 (the Balearic Crane). Pulse 130 to 140. Animal 
phthisical. First sound long and obtuse, second sound in- 
distinct. 

In No. 6 (the Common Crane). First sound short, and no 
second sound heard. 

In No. 7 (the Brahmin Bull). Pulse 80. Animal phthisical. 
First sound long and obtuse, second sound indistinct. 

In No. 8 (the Puma). Pulse 86. Animal sickly, probably 
phthisical. Grating murmur with the first sound. 

In No. 9 (the Indian Antelope). Long obtuse first sound, 
short flapping second sound. 

In No. 10 (the Elephant). Pulse 36. Long and obtuse first 
sound, and relatively short and flapping second sound. 

In No. 11 (the Dromedary). Pulse 48. Long and obtuse 
first sound, short second sound. 

In No. 12 (the Antelope). The first sound longer and 
duller, the second sound shorter and sharper. 

In No. 13 (the Water Buffalo). Pulse 60. Blowing murmur 
after the first sound, no second sound heard. 

In No. 14 (the Giraffe). Pulse 50. Second sound some- 
times double. 

In No. 15 (the Lion). First sound long and obtuse, second 
sound short and flapping. 

In No. 16 (the Nylghau). First sound normal, second 
sound indistinct. 

In No. 17 (the Wapiti Deer). Pulse 60. First sound long 
and obtuse, second sound short and flapping. 



ON THE MOTIONS AND SOUNDS OF THE HEART. l73 

In No. 18 (the Hyaena). Long obtuse first sound, short 
second sound. 

Some other animals were attempted, but without success ; 
viz., the Dzagetai or Wild Ass, the Rhinoceros, the Cas- 
sowary, and some others. As a general observation, the Com- 
mittee may state, that wherever the two sounds of the heart 
could be distinguished, the character of those sounds and the 
rhythm of the heart's motions appeared to correspond with 
those of the human heart, due allowance being made for dif- 
ferences of size in the animals, differences of temperament, 
and the circumstances of excitement or of disease under which 
many of the animals laboured, when they were subjected to 
auscultation, &c. 



Experiments of the Committee for 1839-40. 

In consequence of having been nominated to conduct the 
experiments on the motions and sounds of the heart for the 
current year, without being associated with any colleagues, I 
thought it desirable to avail myself of the assistance of such of 
my friends, including the other members of last year's Com- 
mittee, as could attend, and I accordingly requested the co- 
operation of a considerable number of gentlemen known to 
the public ; of these, several were enabled to attend on numer- 
ous occasions, and one of them, Dr. Boyd, on every occasion; 
so that every observation and experiment has been participated 
in or at least witnessed by one, or, in most instances, several 
of the following gentlemen : 

Professor C. J. B. Williams. 

George Gulliver, Esq., F.R.S. 

John George Perry, Esq. 

Dr. G. Hamilton Roe. 

Dr. George Bun'ows. 

Charles Cochrane, Esq. 

Dr. Rutherford. 

Francis Kiernan, Esq., F.R.S. 

J. Liddell, Esq. 

Francis Samwell, Esq. 

Dr. Edwin Harrison. 

R. A. Stafford, Esq. 

Benjamin Phillips, Esq., F.R.S. 

Dr. Robert Boyd ; 



174 REPORT — 1840. 

and other gentlemen, private friends of the Reporter, and the 
last four-named gentlemen his colleagues in the medical staff 
of the St. Marylebone Infirmary. 

The experiments were performed in a convenient locality 
immediately adjoining to the Marylebone Infirmary, and prin- 
cipally on donkey colts of a few months old. In the latter 
part of the series other animals, and especially dogs, were 
used, partly for economy, and in order that the limited pecu- 
niary resources of the Committee might not be prematurely 
exhausted, and partly because certain experiments contem- 
plated were expected to prove more easily and decisively 
practicable on the larger heart of the ass than on any smaller, 
such as that of the dog ; and that, in any event, it was de- 
sirable to extend the range of observation, as far as practi- 
cable, over the animal scale. 

The mode of preparation was in all cases nearly the same. 
In almost every case sensibility was withdrawn as completely 
as was practicable by one method or the other. In donkeys 
we availed ourselves of the stupefying property of the woorara 
poison, for a packet of which the Reporter had been indebted, 
since 1838, to the kindness of Sir B. C. Brodie, Bart. The woo- 
rara was brought into operation by injecting a couple of grains 
of it, partly dissolved, partly suspended in water, into the exter- 
nal jugular vein, as practised by Mr. Mayo in an experiment 
of Dr. Hope's, and the injection was usually followed in a 
very few minutes by complete insensibility. In the smaller 
animals prussic acid was used in several instances; and in a few 
cases the subject was stunned by a blow on the head. Artificial 
breathing was used in every warm-blooded subject, by means 
of a bellows and long flexible tube kept loose in the trachea. 
The chest was opened nearly as directed by Galen*, and as 
practised by former Committees ; five or six ribs were sepa- 
rated from the sternum and broken near the articulations, and 
bent back over the vertebrae. In every case, whether during 
the preparation or subsequent observation, all convenient 
means were used, as advised by Galenf, to prevent or lessen 
haemorrhage, in order to avoid as much as possible the 
anomalous modes of action attending extreme vascular deple- 
tion, and to prolong the opportunities of observation and 
experiment. 

The observations about to be detailed consist partly of 
experiments in continuation of the inquiries of former Com- 
mittees, and partly of experiments made with a view to decide 

* De Admin. Anat. 1. vii. c. 12. f Loc. cit. 



ON THE MOTIONS AND SOUNDS OF THE HEART. I'JS 

several points in dispute amongst physiologists of authority, 
which were not investigated by those Committees, and which 
seemed to the Reporter yet unsettled, and at the same time 
important enough to call for direct experimental investiga- 
tion. The following are the principal of those undecided 
questions : — 

1. With respect to the rhythm of the motions of the auri- 
cles and ventricles, several living distinguished physiological 
writers appear to hold, that those cavities act in strict alterna- 
tion with each other, and not continuously or in immediate 
succession, the auricles being first always in systole and dia- 
stole, and the ventricular actions being last before the Rest, as 
described by Steno, Harvey, Lancisi, Haller, Senac, &c., and 
by Hope, Williams, Carlisle, Pennock, and Moore, and other 
living authorities. 

2. With respect to the share in the circulation due to the 
auricular systole, it has been held to be active and of much 
importance, by Hervey, Senac, and others ; while several living 
writers of great weight, adhering apparently to the views of 
Galen, Vesalius, &c., seem disposed to refuse to the auricles 
any very influential or positively important share in the cardiac 
operations ; for examples I may cite Dr. Elliotson, Prof. 
Bouillaud, Dr. Hope, Sir B. C. Brodie, &c. 

3. With respect to the shape and dimensions of the ven- 
tricles in systole, it was held by Galen, Vesalius, Harvey, 
&c., that the heart is shortened in diastole and lengthened in 
systole; but the observations of Steno, Lower, Lancisi, Haller, 
and others, gave currency to opposite views ; of late, however, 
the ancient opinion has been revived, for example, by Prof. 
Burdach and Prof. Bouillaud, as I understand their observa- 
tions, and by Drs. Pennock and Moore, the latest experi- 
mentalists on the subject that I know of, except my friends 
and myself. 

4. With respect to the praecordial impulse, the great ma- 
jority of physiologists, adhering unqualifiedly to the ancient 
opinion advocated by Hippocrates and Galen amongst the 
Greeks, and by Vesalius, Harvey, Lancisi, Senac, Haller, 
Hunter, and almost all modern writers, ascribe the cardiac 
pulsation to a blow or stroke (in the popular meaning of those 
words) given by the heart's apex in systole to the ribs ; while, 
in opposition to this view, may be cited the experiments of 
several recent observers, and the arguments of Mr. Carlisle, of 
Dr. Hope in his last edition, of Mr. Bryan*. Dr. Billing. 
&c. &c. 

5. With respect to the diastole of the heart, it was held by 

* Lancet, v. 29. 



176 REPORT — 1840. 

Galen and Vesalius to include a strong force of suction, by 
which the venous current was much forwarded, and the auri- 
cles were more or less emptied ; and this power of inhalation 
or suction has been adopted by numerous living authorities, 
ex. gr. Prof. Bouillaud, Dr. Hope and Dr. Copland, and has 
even been extended to the auricular diastole, ex. gr. by Dr. 
Alison and Dr. Elliotson. The exertion, however, of any such 
force has been distinctly refused to the diastolic state by 
Harvey, Lower, Senac, &c., and appears. Dr. Joy remarks, to 
rest on no satisfactory experimental evidence whatsoever. 

6. In addition to active pulsations observed in certain ani- 
mals in the veins (as in horses, rabbits, dogs, fowls, frogs, &c.), 
there have been noted by several experimentalists, of whom it 
is sufficient to name the great Haller, certain passive pulsa- 
tions, viz. an abrupt diastole of the vein attending the first 
part of the heart's systole or the auricular contraction, and an 
abrupt systole of the vein attending the first part of the heart's 
diastole on the dilatation of the auricle ; but the connexion 
between the venous regurgitation and the auricular systole has 
been doubted by several apparently, and even denied by Dr. 
Elliotson. 

7. Reverting to the auricular functions, the systole of the 
auricles has usually been regarded as unattended by any in- 
trinsic sound. Dr. Hope denies that any such sound occurs, 
and on mechanical grounds seems to affirm that it is not pos- 
sible ; and Dr. Joy calls the auricular systole a " silent" act*. 
Six months, probably, or more, however, before the Committee 
for 1840 had even begun their experiments, Drs. Pennock and 
Moore had, unknown to the Reporter and his friends, detected, 
as they conceived, an auricular systolic sound, in a series of 
very interesting experiments, of which an account is pub- 
hshed in the American Journal of Medical Science, Part L., 
for February, 1840. 

Some other often-agitated and still unsettled points have 
appeared to the Reporter, in like manner, to stand in need of 
further examination; ex. gr. 1. the sizes of the ventricles, &c. 
with respect to each other ; 2. the production of sound by 
certain muscles, while vigorously contracting ; 3. the rhythm 
of the cardiac and arterial pulses, &c. &c. Finding on all the 
preceding points considerable differences of opinion, and per- 
ceiving that, in many instances, the decision of highly-distin- 
guished and leading physiological writers was at variance 
with the best hitherto-recorded experiments and observations, 
the Reporter found forced on his mind the conviction, that on 
all or most of those points further data were wanting, and 
♦ Library of Practical Medicine. 



ON THE MOTIONS AND SOUNDS OF THE HEART. l77 

experiments less ambiguous and more pointed and conclusive. 
Under such impressions, the Reporter felt himself at liberty, if 
not positively called on, to advert to various questions above 
alluded to, which had not been handled by former Committees, 
provided that, by any unlooked-for good fortune, if not through 
some new and happier experimental combinations, he should 
succeed in eliciting pertinent and decisive facts. Acting on 
such views, the Committee has put to the test of experiment, 
to a greater or less extent, several of those questions, with 
results now to be stated. 

It may be proper to state, that the instrument used in 
auscultation was exclusively the flexible ear tube ; the wooden 
stethoscope, comparatively inconvenient in almost all cases, 
being found quite unsuited for such experiments. 

Observation I. 

June 11th. — Subject, a Donkey about ten weeks old and 
sound in all respects. Phcenomena : Various spontaneous ir- 
regularities in the cardiac action and sounds ; — -jerking upwards 
Sfc. of perijihery of inter-nal valves in systole ; — appearances 
of auricles in action ; — effect of valvular obstruction on first 
sound. Heart, when exposed, acting strongly and quickly. 
Second sound indistinct, and loud murmur with the first 
sound. 

S. 1 . On placing the finger on the outer periphery of the 
mitral valves, an upward jerk and thrilling motion sensible, 
similar to that observed over the arterial valves. 

S. 2. At the moment of auricular systole, were noted a 
dimpling of the appendix, and an abrupt contraction in all 
its dimensions, and a sinking (as it were) downwards and in- 
wards, followed by a gradual return to the state of promi- 
nence and distention that characterize the auricular diastole. 
Several times was observed a slight and partial active contrac- 
tion of the auricle, followed by relaxation in the intervals of 
full and complete auricular systole and diastole, as if from 
transient spasmodic disturbance. 

S. 3. The second cardiac sound observed at intervals to 
be for many minutes together wholly wanting, without obvious 
cause ; no operation upon the mitral or other valves having 
been hitherto attempted. 

S. 4. The left auricle was inverted successively by the 
finger and by a probe, so as to impede the action of the 
mitral valves ; the finger was sensible, when placed in the 
mitral orifice, of an abrupt though gentle concussion in the 
systole of the ventricle, and (it seemed to me) as if it were 

VOL. IX. 1840. N 



178 REPORT — 1840. 

pushed by a cord or membrane stretched obliquely across the 
passage, and brought suddenly to a state of tension ; and at 
the same time the sensation of jerking upwards was much less 
distinct when a finger was placed over the valve externally. 
The probe also, when held loosely in the orifice (enveloped, 
like the finger, in the inverted appendix of the auricle), was 
felt and seen to be pushed back in each systole between the 
fingers. 

S. 5. At the moment of introducing the inverted appendix 
into the internal opening, the sharp well-defined beginning 
of the first or systolic sound was wanting or obscure ; and 
that sound seemed to several observers less abrupt and more 
gradual in its development. 

Observation II. 

June 13th. — Subject, a stout Ass two to three months 
old. PhcEnomena : Abnormal murmurs, without structural 
defect ; — motions of the ventricle in systole, as apparent to the 
eye and hand ; — same of the auricles ; — rhythm of the motions 
of auricles and ventricles ; — aurictdar hcemorrhage not sus- 
pended in diastole, and augynented in systole of auricle. 

S. 1. Heart acting normally and vigorously before the in- 
jection of woorara. Immediately after the operation was com- 
pleted, a murmur was observed with the second or diastolic 
sound, with a slow cardiac action ; the first or systolic sound 
being normal. 

S. 2. In systole, motion first distinctly observed at the 
fundus, especially on the right ventricle, where any phgeno- 
mena about the arterial orifice are most easily observed in 
animals lying on the right side ; apex almost simultaneously 
moved with fundus. These systolic motions in the ventricles 
were preceded by a dimpling and shrinking inwards and 
downwards of the auricular appendices, but by a very minute 
interval, so that the aui'icular motion seemed as it were but 
the first portion of a more extensive movement affecting the 
whole heart. 

S. 3. Before opening the pericardium, needles were passed 
horizontally through that organ without wounding the heart, 
and so that they lay exposed to the eye in their whole length, 
except the minute portion actually penetrating the pericar- 
dium, and over the following points, — viz. over the auricle, over 
the periphery of the mitral orifice, and over the apex ; and 
observation was made through a roll of paper employed to 
limit the field of vision, and a succession of motions was di- 
stinctly noted ; first, about the fundus and insertions of the 



ON THE MOTIONS AND SOUNDS OF THE HEART. 179 

great arteries, and most strikingly over the appendices auri- 
cularum, and thence propagated as it were toward the free 
extremity of the heart, being perceived in the body of the 
ventricles next after the fundus, and at the apex last, as if an 
impulse in a compressed fluid, or a wave commencing about 
the insertions of the arteries, had been propagated along the 
heart from fundus to apex. 

S. 4. After opening the pericardium, small triangular bits 
of white card were applied so as to adhere to the left appen- 
dix, fundus of left ventricle, middle of same cavity, and close 
to the apex ; and observation was made, as in last experiment, 
through rolled paper, and with like results (as in S. 3.). 

S. 5. And this seeming propagation of motion was per- 
ceived next in another way, viz. by pressing gently on the 
fundus and body of the ventricle and on the apex, by which 
was elicited a sensation, or series of sensations, as of a pro- 
gressive movement of an undulatory character directed from 
fundus to apex, and resembling, to a considerable extent, that 
given by a dropsical abdomen, or hydrocele, &c., when ap- 
propriately percussed. 

S. 6. During a very vigorous action of the auricles, and at 
a somewhat advanced period of the observation, the shrinking 
and dimpling, in its centre, of the appendix in its systole, was 
likened by several observers to an effect either of suction or 
of some traction exerted on the appendix from some point 
about the auri-ventricular opening, more especially because it 
seemed often separated in time from the ventricular tension, 
roundness and impulse (^. e. systole) by a scarcely perceptible 
interval. 

S. 7. Toward the end of the observation, and during a 
tolerably regular and vigorous action of the heart, the tip of 
the left auricle was snipped off; after which the contractions 
of the appendix became indistinct, those of the ventricle being 
at first little affected. On the instant of cutting off the appen- 
dix, a profuse flow of blood occurred in a stream slightly in- 
creased by a jet during systole of the auricle, and continuous, 
and without any jet, during diastole. 

Note. — The heart ceased to beat after about three quarters 
of an hour of observation, owing to the inflating tube becom- 
ing obstructed by a clot of blood which escaped timely detec- 
tion ; it was quite healthy ; the ventricles appeared not to differ 
in size. 



N 2 



180 REPORT — 1840. 

Observation III. 

June 22. — Subject, a Donkey about six months old, in good 
health. PhcEiiomena : Results of application of pressure in 
various ways to the ventricles ; — rhythm and maimer of motions 
of fundus and apex in systole and diastole ; — motions in the 
arteries and over the valvular orifces ; — action of the sinuses in 
systole of auricles ; — shortening of heart in systole ; — effects 
of wounding an auricle, 8fc. Sfc. 

S. 1. Callipers were applied to the ventricles, as if to take 
the diameter of the heart. The legs of the calhpers before 
use had been fastened together by an elastic chord of con- 
siderable resisting power. In whichever direction the instru- 
ment so prepared was made to embrace the ventricles, whether 
exactly transversely or obhquely, the uniform result was, that 
the legs of the instrument were separated with force, and re- 
ceded from each other in each systole, and approached each 
other in each diastole with depression of the part of the parietes 
they pressed on ; which depression wholly disappeared in the 
systole, giving place to an opposite state of the parts, or to a 
state of convexity and apparent protrusion. 

S. 2. The finger and thumb were then applied to opposite 
sides of the ventricles, and were felt to be abruptly pushed 
outwards in systole, and to approach each other in diastole, if 
acted on even slightly by the flexor muscles, and with marked 
depression of the parietes in diastole, during which no sense 
of active resistance was experienced. 

S. S. A wooden stethoscope was then placed on the ven- 
tricles, and kept erect by means of a roll of paper large 
enough to give the instrument full freedom of motion ; and 
the uniform result was, that wheresoever placed on the ventri- 
cles, the stethoscope was heaved up with a jerk at each systole 
(to the height of half an inch near the fundus), and subsided 
at once in diastole, causing in the parietes a deep depression, 
which was wholly removed by the systole, and succeeded by 
an opposite shape of the surface. 

S. 4. To the eye and hand the fundus appeared to become 
round, hard, and elevated, and to give impulse somewhat 
sooner than the apex, as if the systole was developed earlier 
about the fundus than at the free extremity of the heart. 

S. 5. To the fingers, during the systole of the ventricles, a 
feeling was communicated, as of an undulation in a com- 
pressed fluid, very distinct, and c^rected from fundus to apex, 
and resembling sensations familiar to physicians in ascites, hy- 
drocele, &c., when properly percussed and manipulated. 



I 



ON THE MOTIONS AND SOUNDS OF THE HEART. 181 

S. 6. On touching the arteries close to the heart a feeling, 
as of efflux and reflux, was very distinct, especially in the 
aorta, the foi'mer coinciding with the systole of the ventricles, 
the latter with the diastole. At the same moment with the out- 
ward current in the arteries, or during the ventricular systole, 
a peculiar jerking upwards of the periphery of the auri-ven- 
tricular orifices, — and a similar eccentric movement was ob- 
served over the arterial openings during the reflux current or 
andulation in the vessels, i. e. during ventricular diastole. 

S, 7. The sinuses of the auricles v/ere found by the touch 
to contract vigorously, before the ventricles considerably, and 
even before the shrinking, &c., or systole of the appendices. 

S. 8. Small three-triangular pieces of white card were made 
to adhere to the fundus and apex cordis respectively, and ob- 
servation was made through a roll of paper sufliciently large 
to take in, at a convenient distance, both extremities of the 
organ, and held so that each white object rested on a distinct 
limb of the tube's mouth, and every change of distance be- 
tween the points dotted white was readily detectible, — and the 
uniform result was, that the apex approached the base in 
systole and receded again in diastole, and the range of oscil- 
lation seemed about ^vd of an inch. 

S. 9. While the heart still acted, but with much diminished 
force, a cut was made in the right auricle and a copious flow 
of blood obtained, having slight jets in the auricular systole, 
and immediately before the ventricular hardening, elevation, 
&c., but being continuous during diastole. 

Note. — The ventricles appeared not to differ in size on care- 
ful examination — post mortem cordis. 

Observation IV. 

June 27. — Subject, a stout Ass three to four weeks old. 
Heart acted very vigorously until weakened by haemorrhage, 
and continued to beat with considerable energy for two hours, 
when it was extracted, still contracting. P/icenomena : Effects 
of various forms of pressure on the heart ; — rhythm of cardiac 
and arterial pulses ; — ventricular systole ; — auricular ditto ; — 
sound of auricular systole ; — pulsation of cava ; — auricular 
diastole ; — spontaneous or incidental variations in cardiac 
sounds ; — protrusion of septum into right ventricle in systole, 

S. 1. A stethoscope loaded with 2 lbs. weight of shot in a 
bag, was placed on the heart before opening the pericardium 
(as in experiment 3 of last observation), and was raised at 
each systole with a sudden heave or jerk, and with much 



182 REPORT 1840. 

force, and subsided immediately on the supervention of dia- 
stole, causing a deep depression in the previously convex sur- 
face of the ventricle. This experiment was repeated toward 
the close of the observation, and after the heart had been ex- 
posed for 1 hours and with like results in all respects. 

S. 2. The pulse of the femoral artery, being compared with 
that of the heart, was found to follow the latter by a distinctly 
perceptible interval, but one very minute. 

S. 3. To the eye the apex and fundus cordis approximated 
to each other in systole, and receded in diastole. The motions 
of those parts coincided to a great extent, but not entirely, 
but rather as parts of a series of concatenated movements, of 
which the former part was the profound undulation, harden- 
ing and rounding of the fundus, and the latter part the 
hardening, shortening, and slight elevation of the apex; be- 
tween these successive appearances, no very distinct interval ; 
they passed into each other by an undulatoi-y sort of motion, 
commencing at the fundus, and passing with extreme rapidity 
along the ventricles to the apex. 

S. 4. Threads were passed through the appendices of the 
auricles, and being held tense, so as to impede the auricular 
systole, were felt to be drawn downwards with much energy 
immediately before the systole of the ventricles, the auricular 
contraction being completed, while the ventricles were still 
developing their systole. 

S. 5. Toward the close of the first hour of observation, 
and while the heart in its different parts acted with much 
energy, the auricles were observed for a time to contract with 
a rhythm above double that of the ventricles (owing probably 
to the irritation excited by passing the needle and thread 
through the appendices, and pulling at them afterwards), and 
a sound was detected resembling very much, except in volume, 
the first or ventricular systolic sound, and accompanying the 
auricular systole. The sound was short, rapid, obtuse, without 
any jerking motion, and coincident exactly with the auricular 
systole, and in number double (or rather more) the sound of 
the ventricular systole. This sound was found to attend the 
systole of the right auricle as well as that of the left, at a time 
•when the action of the latter was too feeble to give sound. 

S. 6. The large pectoral veins, especially the cava, were 
observed to pulsate with the auricular systole, something as 
the arteries do with the ventricular, but comparatively very 
feebly ; first came the diastole of the vein and then the systole, 
and then the Rest, and the former followed immediately on 



ON THE MOTIONS AND SOUNDS OF THE HEART. 183 

the auricular systole, and the latter on the diastole of the 
auricles, both in the inferior and superior cava ; no other 
motion was noted in the veins. 

S. 7. The diastole of the auricles was a gradual swelling 
and enlargement of the visible parts of the cavities in all 
directions, requiring for its completion as much time as several 
systoles would do; and followed, on the instant of the full 
distension of the appendices, by systole of the whole heart, — 
first in the auricle, and then instantly in the ventricles : during 
its diastole, the auricle seemed to the eye to emerge, as it 
were, from the sinus venosus, and to swell out from a state of 
collapse, such as suction inwards toward the ventricle might 
cause, if any such force as suction existed in the heart. 

S. 8. In this, as in every observation, abnormal murmurs 
were observed at various moments, viz. immediately on the in- 
jection of the woorara, and at other times, but especially when 
pressure was made, whether intentionally or otherwise, over 
the orifices, exterior and interior, of the heart. Toward the 
close of the observation, a loud musical sound was detected in 
the pulmonary artery with the diastole- At various times, for 
short spaces, the second sound of the heart was indistinct or 
absent, or masked by murmurs, without obvious cause in most 
instances, other than abnormal modes of action from irri- 
tation, haemorrhage, &c., exclusively of known structural 
changes. The first sound of the heart was often modified in 
various ways, and attended by murmurs, but never was want- 
ing so long as the heart acted with any energy. Toward the 
close, however, when the ventricular systole had become slow 
and gradual from quick and abrupt, the first sound was either 
very feeble, or not distinguishable at all. 

S. 9. The pulmonary artery was cut open ; after which the 
first sound was still heard, but rather obtuse. A finger was 
then passed into the right ventricle, and the septum was felt 
to project convexly into the cavity, and in each systolic effort 
to press against the finger. 

Note. — Post mortem. One valve of the pulmonary orifice 
was found slightly injured by a puncture made in the course 
of experiments, in which the parietes cordis had been irritated 
to abnormal action by means of a needle. Wherever the needle 
penetrated into a cavity of the heart, there a clot was found, 
or at least a coloured plug of lymph in the internal opening. 

Post mortem. The ventricles were found to be of the same 
dimensions on careful examination. 



184 REPORT— 1840. 

Observations V. and VI. 

July 1st, 1840. — In two observations, one on a Frog and a 
second on a Rabbit, the following results were obtained : — 

Rhythm : The first contraction after the pause or cardiac 
diastole was observed in the vena cava, to which immediately 
succeeded contraction of the sinus, and afterwards, immedi- 
ately, of the appendix of the auricles ; to which latter, imme- 
diately succeeded the ventricular systole ; and the diastole, or 
relaxation of each part, succeeded in like order, — that of the 
vein first ; then of the auricle, of which the appendix seemed 
later in its diastole than the sinus or body ; then of the ven- 
tricles. Those motions were much slower than in the human 
subject — somewhere about fifty beats per minute. The series 
of systoles above mentioned succeeded each other, so that at 
a little distance they appeared collectively like an undulation 
commencing at the cava, rather than a series of independent 
actions. — Systole of ventricle : In diastole the ventricle was 
round, full, protuberant, and dark in colour ; but on the 
supervention of systole changed rapidly in shape and colour, 
from purple, becoming pale flesh colour, like veal ; and from 
round and broad, becoming apparently narrower and more 
conical and depressed ; being obviously lessened in all dimen- 
sions, but most strikingly in the transverse. The action of 
the heart lasted for an hour or more with great regularity ; 
the auricles acted for some time longer than the ventricle, 
especially the right auricle. 

Observation VI. 

In the rabbit, the heart did not beat at any time very 
vigorously or regularly, and ceased altogether after 20 to SJ5 
minutes, although respiration was maintained by the bellows 
with ease. 

The Rhythm : S. 1. The first motion after the Pause or 
ventricular diastole was observed in the base of the auricles, 
and on the right side in the expansion of the jugular and sub- 
clavian veins, which in the rabbit, as Steno has noted, seemed 
to replace the superior cava. This vessel, whose dimensions 
were very large compared with the heart, and which wound 
round the root of the heart in its way to the auricle from above 
downwards, and from left to right, continued to pulsate for 
some time after the ventricles had ceased, and even after the 
adjoining auricle had been for some minutes inert. Nearly, 
but not quite, at the same instant of time with the vein, the base 
and then the apex of the auricle were seen to contract ; after 
which (but not so quickly as might have been expected from 



ON THE MOTIONS AND SOUNDS OF THE HEART. 185 

other observations, owing probably to delay in the establish- 
ment of artificial breathing) the ventricles entered into their 
systole, and the diastole followed in like order ; first, the venous 
expansion, next the base and appendix of the auricles, and last 
of all the ventricle. 

S. 2. In the systole some change of colour was observed 
in the ventricles, from darker to paler, and the same in the 
auricles. 

S. 3. Toward the close of the observations, the auricles 
acted much more frequently than the ventricles, and especially 
the right auricle. In the ventricular systole the apex was 
thought to move slightly outwards and to the left, or away 
from the septum or central axis of the heart. 

Observation VII. 

July 2nd. — Subject, a snake of good size, poisoned with 
prussic acid, so as to be insensible. Heart beating very 
slowly and rather irregularly at first, from 15 to 20 beats per 
minute only. 

Rhythm of motions : After a long pause, first motion ob- 
served in sinus of auricle, and then in appendix, being the 
auricular systole ; immediately after which the ventricular 
systole, but with no complete interval between the end of one 
and beginning of the other systole. After the systoles re- 
spectively came the diastoles in like order, and then a long 
pause, equal sometimes to 3 or 4 or more beats. 

At each auricular systole, a swelling observed in the cava 
and pulmonary veins, extending some way down from the 
heart. This appearance resembled a wave of reflux excited 
by the action of the auricle. It was not observed in any part 
beyond a point of the vessels on which pressure was made. 
In the systole, the ventricle shrank concentrically, being 
shorter and narrower, but also rounder and more oval, than in 
diastole ; the ventricle (which might be called bicornute, being 
obtusely pointed at either extremity,) had either horn or ex- 
tremity raised slightly in systole, and depressed again, as if by 
gravitation, in diastole. The cavities systolized and diastolized 
still after the observation was completed, or for more than an 
hour, and more regularly than at first. 

July 2nd. — The ventricle ceased beating after about twenty 
hours, but the auricles were still pulsating regulai'ly after more 
than twenty-four hours. The rhythm of the motions of the 
heart as before, but the reflux wave or diastole of the veins 
now less distinct, owing probably to the emptiness of the 
heart. And in lieu of the regurgitation wave marked by a 



186 REPORT — 1840. 

diastole, followed by a systole, and then a pause in the veins, 
there was observed an opposite order of the motions, viz. 
1. venous systole; 2. venous diastole; 3. then the pause. 
Several times the motions of the veins were observed alone, 
and not preceded by auricular contraction, or accompanied by 
it, as, toward the close in other observations, auricular con- 
traction had often failed to excite or be followed by ventricu- 
lar systole. 

Observation VIII. 

July 4th. — Subject, a Donkey nine months old, in good 
health. Pulse beating well in prsecordia about 70 or 80. Opera- 
tion of injection tedious, with considerable haemorrhage ; whole 
operation lasted half an hour, and heart acted for considera- 
blv more than an hour. When opened, the heart was beating 
quickly (above 100) but regularly. Second sound indistinct. 

Pheenomena : Effects of pressure on the heart ; — action of 
threaded auricles ; — no sound, and why ; — manner of auricular 
diastole ; — resistance to pencil in mitral orifices, and how 
caused;— pulsation of cava ;—phcenomena of ventricular sy^ 
stole; — mechanism of cardiac impulse ; — valvular jerk over the 
mitral opening in systole, and modifications of first sound arti- 
ficially produced ; — hemorrhage from left auricle ; — relative 
sizes of ventricles. 

S. 1. The stethoscope, loaded with 4 to 5 lbs. of shot, &c., 
and placed on the ventricles as before, was jerked up by each 
systole, and subsided and deeply indented the parietes in 
each diastole. 

S. 2. The callipers were applied as before, but with a ten- 
sion much exceeding that formerly used, and with a similar 
but not equal result ; the heart being considerably less vigor- 
ous, as well as the spring much stiiFer. The action became 
much hurried under the pressure of the instrument, but its 
lees were pushed asunder with force in systole, and a deep 
indentation was caused by them in the parietes in diastole, 
which did not wholly disappear sometimes in systole. 

S. 3. The tip of the appendix of the left auricle was 
threaded as before, and the auricle and ventricle acted nearly 
but not exactly in alternation, and the thread was felt to be 
forcibly drawn downwards at the moment of auricular dimp- 
ling and systole. 

S. 4. No auricular sound could be distinguished, apparently 
less attributable to want of enei'gy in the auricle than to the rapid 
beat of the heart and sudden supervention of the ventricular sy- 
stole before the completion of the auricular. The left appendix, 



ON THE MOTIONS AND SOUNDS OF THE HEART. 187 

was repeatedly inverted with a pencil and with the finger, and on 
the instant of being let free, by withdrawal of the pencil, &c., 
recovered its shape and position, appearing to emerge with 
rapidity out of the auri-ventricular orifice and sinus, appa- 
rently owing to a continuous and copious influx of venous 
blood into the appendix, especially during the systole of the 
ventricles. 

S. 5. In experiments on the mitral valves, repetitions of 
former trials, and with inverted auricles, some resistance, as 
of a hard edge, was repeatedly felt by the finger, and the 
pencil was pushed outwards with some foi'ce, but the edge felt 
was suspected to be the edge of the interior orifice and not 
that of a valve. On the inner side, or that next the septum, 
the resistance in systole was more energetic than on the 
outer. 

S. 6. The thread that had been passed through the ap- 
pendix was drawn upwards, to check the systole of the auricle 
during auscultation, but the operation was with difficulty per- 
formed, and at all events no perceptible difference resulted ; 
the first cardiac sound appeared unchanged. 

S. 7. A slight motion of the cava was observed accompany- 
ing the auricular systole, viz. a diastole followed by a systole ; 
both slight. 

S. 8. In systole the ventricle became rounder, harder, 
tenser, and shorter ; both fundus and apex, but especially the 
latter, were seen to be elevated, and the apex seemed to turn 
slightly from left to right. 

S. 9. An eccentric impulse, or abrupt push outwards, was 
perceived on whatever part of the ventricle we touched, while 
the heart acted with any energy ; and this push or impulse 
was most striking, though least powerful, just at the apex, on 
account, as it seemed, of its pointed form. 

S. 10. An undulatory sort of motion was perceived in 
systole from fundus to apex, along the parietes. In addition 
to the general eccentric impulse, there was observed over the 
orifices, arterial and auricular, a jerking motion not observed 
elsewhere ; and this jerking was indistinct or null over the in- 
terior orifice, in a subsequent experiment, in which the mitral 
valves were prevented from closing by a slender instrument 
something like scissors, the parts of which beyond the joint 
were introduced, through the auricle, without inverting it, into 
the auri-ventricular opening ; and while the blades were kept 
separate, the first sound, as heard on the ventricles, was 
found to begin dull and obtuse ; and an obtuse beginning, and 
a well-defined beginning were heard alternately, according as 



188 REPORT— 1840. 

the blades were separated or brought together, and as conse- 
quently the valves were obstructed or left free. 

S. 11. The tip of the left auricle was snipped off and hae- 
morrhage was excited, which was constant but with slight jets 
at the systoles of the auricles. 

Observations IX. and X. 

July 7th. — Operated on two Rabbits ; one a large vigorous 
domestic one, and the other a smaller wild one ; both stunned 
by a blow on the head. The larger one was violently convulsed 
before death, and when the chest was opened the heart was 
not beating, and the only result obtained was — 

S. 1. Distinct beatings in the large vein on the left side 
which winds round the base of the heart to empty itself in the 
right auricle ; the actions observed were a systole followed by 
a diastole, and then a short pause ; there was no auricular sy- 
stole ; the venous beating continued for many minutes. 

S. 2. The second heart acted for some minutes with some 
energy, especially the right cavities ; the left cavities were 
drained by haemorrhage, owing to an accidental wound in tlie 
superior great vein in opening the thorax. For some minutes 
the rhythm of the action of the cavities went on normally ; 
first, the very rapid and abrupt auricular systole, and then 
immediately the ventricular systole more gradual and of longer 
duration, and then the pause. 

S. 3. When the left ventricle acted, the apex cordis seemed 
slightly deflected to the left in systole, dragging the apex of the 
right after it ; and when the right ventricle acted alone, no de- 
flection was observed. 

S. 4. For a considerable time after the cessation of the left 
side, the right cavities acted regularly, but after five to ten mi- 
nutes, the ventricle especially began to flag, and the auricle 
then acted frequently without any following ventricular systole. 
But on one occasion, without obvious cause, the auricle became 
sluggish, and even for a few moments motionless, while the 
ventricle acted by itself more than once. 

S. 5. In the systole, the apex approached the base, and the 
opposite sides approached the septum cordis, and the whole 
organ became rounder and more globular. In one direction, 
viz. the vertical, the heart always, when acting with any energy, 
became larger, while every other diameter was diminished. 

S. 6. After cutting out the heart, and before cutting out, 
but after cessation of spontaneous motion, systole was easily 
excited by irritating with scissors, etc., and after the left had 
nearly wholly ceased to answer stimuli, still the right ventricle 



i 



ON THE MOTIONS AND SOUNDS OF THE HEART. 189 

contracted on the point of a scalpel being applied to the left 
ventricle. 

Observations XL and XII. 

July 1 1 . — Phcenomena : Stroke and sound obtained as if from 
locomotive force in systole of ventricles; — rhythm of the heart's 
motions ; — manner of auricular action ; — same of the ventri- 
cular-venous motions ; — mechanism of the cardiac throb or im- 
pulse ; — mode of hoemorrhage from a wounded auricle. 

Subjects, two Donkeys operated on ; one about six weeks 
old, the other about two and a half months ; both rather weak 
from fasting twenty-four hours, owing to being too young to 
eat or drink properly. Each heart ceased to beat after about 
half an hour. First animal had his forehead beaten in so as to 
stun him, and chest then opened. Heart acted quickly and not 
very regularly. No distinct second sound ; no auricular sound. 

S. 1. Before opening pericardium, a hard flat body, having 
a piece of lead weighing about a quarter of a pound fixed on 
it, was placed on the heart, and a stethoscope was held at a 
short distance over it, i. e. at a quarter to half an inch, and at 
each systole of the heart the lead rose up abruptly and struck 
the stethoscope with a tick, audible at some yards distance, 
and receded with diastole to sometimes nearly half an inch, 
and again rose up and impinged on the tube in systole, and 
so on. 

S. 2. The pericardium was then opened, and the auricles 
and ventricles observed. No auricvdar sound could be detected. 
The auricles acted immediately before the ventricles, and after 
the pause or rest, and very abruptly and rapidly: the heart acted 
rapidly, probably considerably above one hundred per minute. 

S. 3. The auricles were observed in systole to dimple and 
contract all round from periphery to centre, as in former ob- 
servations. 

S. 4. The changes of shape in the ventricles were particu- 
larly plain and striking — the apex moved slightly upwards and 
to the left, and was drawn toward the base in systole, while 
the horizontal transverse diameter of the heart, as the animal 
lay on its right side, was diminished, and the transverse verti- 
cal diameter, and that alone, was increased, owing to the heart 
becoming from flattish, inferiorly and superiorly, convex, and 
from in the centre compressed or depressed, strictly globular 
or protruding, so that the central longitudinal axis was elevated 
during systole, and lowered in diastole, while in diastole 
the apex rather approached the sternum from which it had 
receded in systole, owing to shortening of the organ. 

S. 5. The veins w^re observed, and except perhaps a slight 



190 REPORT— 1840. 

undulation downwards during auricular systole evinced by a 
diastole followed by a systole, both very slight, nothing decided 
was observed. As in all former observations the ventricles 
and auricles respectively acted together. 

Observation XII. 

The second and older animal was prepared by injection of 
woorara, and, after establishment of artificial breathing, the 
left ribs were cut quite close to the mesial plane, so as to 
expose fully the apex in every motion. 

(Note. — The former was opened in the same way and with 
the same effect.) The pericardium was then opened, and the 
following results were obtained. 

S. 1. The hard substance (sole leather) weighted with lead, 
was applied to the heart, and the same result as in the former 
experiment obtained, viz., a sudden abrupt elevation or jerk 
upwards of the lead was obtained, and a stroke against the 
stethoscope heard distinctly at several yards, and the range of 
oscillation or motion of the lead was about half an inch. 

S. 2. On opening the pericardium the auricles and ven- 
tricles were acting as in the former observation, viz., the 
auricles first after the rest or pause, and the ventricles imme- 
diately after the auricles. No auricular sound was detectible ; 
no distinct second sound heard. Heart acting hurriedly and 
with varying quickness, but always above the healthy standard. 

S. 3. The motions of the ventricle very conspicuous, and as 
in last observation, viz., striking diminution of horizontal 
transverse and of longitudinal diameters, and increase of trans- 
verse vertical diameter in systole, and in diastole increase of 
the two former diameters, and decrease of the last. And in sy- 
stole the apex was raised, as was the whole body of heart, by 
an elevation of the central longitudinal axis, which was effected 
partly by the assumption of a globular form in the previously 
compressed central inferior surface, and partly by the visible 
protrusion of the previously depressed central superior surface 
of the ventricles. 

So long as this observation lasted both auricles seemed to 
act with equal pertinacity ; the right auricle being however 
snipped, and long after the ventricles had ceased, the blood 
gushed out of the right auricle only when the auricle con- 
tracted, and the haemorrhage ceased nearly during the diastole 
of the auricles. 

S. 5. No other appearances observed in the veins than in 
the former experiment, viz., a slight diastole with the auricu- 
lar systole followed by a systole with auricular diastole. 



ON THE MOTIONS AND SOUNDS OF THE HEART. 191 

S. 6. In neither of the two preceding observations did the 
auricles and ventricles exactly alternate, but in each, whenever 
observation was carefully made, the auricular systole imme- 
diately preceded the ventricular ; and the ventricular diastole 
preceded the pause or rest, which last was first interrupted by 
the abrupt auricular contraction. 

Observations XIII. and XIV. 
July 15th. — Subjects, a Donkey (about a twelvemonth old, 
prepared with woorara ; very Httle blood lost in opening ; ani- 
mal not healthy, and weak, so as to be ill able to walk before the 
operation ; heart acted pretty well) — and a Dog. 

PhcBnomena : DonJcey — Rhythm of motions ; — character of 
auricular actions ; — same, of the ventricular ; — double friction 
bettveen heart and pericardium normally ; — eccentric impulse 
felt all over ventricles in systole ; — motions of cava. 

Phenomena : Dog — Normal double frictions of pericardium; 
— with other phcenomena. 

S. 1 . Rhythm of motions of the auricles and ventricles was 
as in former experiments ; first, the auricular systole, then im- 
mediately, the ventricular systole, without interval, and as if it 
were a continuation by undulation of the former motion. 

S. 2. Then the pause during which the auricle and ventricle 
became each distended and soft and flaccid, the former sliding 
its extreme margin downwards on the fundus of the ventricle 
toward the apex, to retract it suddenly again toward the 
sinus in systole, — and the latter protruding its apex and sides so 
as to be enlarged in every direction, except that of the trans- 
verse vertical diameter, to retract both apex and sides in the 
following systole, and at the same to rise upwards in its cen- 
tral parts with an impulse. 

S. 3. Before opening pericardium the condition of that sac 
was carefully observed, and it was noted, that while the peri- 
cardium remained stationary under all circumstances, the heart 
suffered much change in shape and size, so that there was in 
every part, and especially over the auricles, a to-and-fro motion 
of the cardiac pericardium on the external layer of that sac, a 
friction in one direction in systole and in the opposite in diastole. 
S. 4. The impulse before observed was obtained by the fin- 
ger applied to any part of the ventricle in systole. 

S. 5. The cava observed, and a slight action was noted, viz. 
a diastole followed by a systole, the former with a wave-like 
sensation of motion from the heart downwards, and accompa- 
nying the auricular systole, and immediately preceding the ven- 
tricular. The separator above described was introduced into 



192 REPORT— 1840. 

the mitral aperture and a murmur was heard ; but the heart 
ceased too soon, owing to errors in the insufflation, to allow of 
the experiment being properly followed out. 

Observation XIV. 

Same day. A Dog, small, and perhaps two years old, was poi- 
soned with prussic acid, and then prepai'ed as usual. The 
heart acted pretty well for nearly half an hour. 

S. 1. The stillness or inertness of the free pericardium and 
constant succession of changes of shape and size in the heart 
were carefully observed ; the heart being, for the size of the 
animal, much larger than that of a donkey ; the experiment was 
much less troublesome from that cause as v/ell as from the 
greater facility of manipulation of a smaller animal. Every sy- 
stole of the auricles produced a double friction, viz., one against 
the external layer of the pericardium and one against the fun- 
dus of the ventricles, or periphery of the auricular orifices; 
and every diastole of course produced friction in the opposite 
directions ; and every systole of ventricle produced friction 
longitudinally from apex to fundus, and transversely from side 
to side, all round the body of the heart ; while every ventricu- 
lar diastole included friction in the opposite directions. 

S. 2. The rhythm of the heart's motions was as before, viz., 
first, the auricular systole, — and secondly, immediately there- 
after, the ventricular, and without marked interval, but, as if the 
latter motion were but a continuation of the former, by a sort 
of continued undulation, — and thirdly, the pause consistingfirst 
of auricular diastole, and then including the immediately suc- 
ceeding ventricular diastole, and interrupted first by the au- 
ricular systole. 

S, 3. Cava observed and motion noted, viz., a diastole fol- 
lowed by a systole, the former synchronous with the auricular 
systole, the latter immediately following. 

S. 4. The subclavian artery laid bare unintentionally for 
several inches, forming an arch more than two inches in length, 
and observed to lengthen without straightening in the systole 
of the heart, and to shorten slightly but sensibly in ventricular 
diastole. 

S. 5. As in every former distinct observation, the sensation 
of impulse was perceptible on every portion of the ventricular 
surface ; the shortening, rounding, hardening, and elevation of 
the central longitudinal axis, and increase of the transverse 
vertical diameter alone, of the body of the heart, easily distin- 
guished, — also the jerking over the orifices, &c., &c. 

S. 6. The auricular systole apparently audible, but the sound 



ON THE MOTIONS AND SOUNDS OF THE HEART. 193 

not separated by any very distinct interval from the instantly 
succeeding ventricular sound, which however it preceded ra- 
ther, and certainly preceded to the senses of touch and hearing 
together, the hardening and rounding of the ventricle. 

S. 7. In the dog, as in the ass, the motions w^ere slovr com- 
paratively in the heart, auricles as well as ventricles. The right 
ventricle first, and afterwards the left ventricle, were punctured 
with a slender glass tube drawn out for a couple of inches at 
the lower end, and the result observed. In systole there was 
a sudden rise in the tube, and a slight subsidence in diastole. 
The subsidence was but slight, the greatest not being in the 
left ventricle more than half an inch, and in the right ventricle 
still less. The sinking of the blood in the tube in diastole was 
such as might be caused by a sudden withdrawal of an impulse 
sufficiently energetic (like that of the systole) to overcome gra- 
vitation abruptly, and so as to excite a jet in a tube containing 
a fluid column sustained by a constant pressure (such perhaps 
as might be produced by the venous influx) from below. 

S. 8. In both hearts the right cavities were relieved from 
distension before complete cessation of action, and the areas of 
the ventricles, judging by apparent extent of walls opened and 
spread out, seemed in no degree to differ. 

Observations XV. and XVI. 

July 18th. — Operated on two Donkeys of from four to eight 
months old. 

PhcBnomena : First donkey — Glass tubes introduced into left 
auricle and ventricle, and results noted ; — normal pericardial 
frictions observed, and several other observations confirmed : 
Second donkey — Blunt Jiook and screw, successively interposed 
between mitral valves with considerable modification of first 
sound; — also, spontaneous abnormal sounds; — auricular sy- 
stolic sound ; — results of introduction of glass tubes into heart's 
cavities ; — confirmation of former observations. 

Woorara injected in each case ; in the first, the operation 
very successful, but in the second, a second dose of two grains 
required. 

In the former, much blood lost, viz., probably owing to an 
accidental cut made in hastily opening the trachea for artificial 
breathing. The heart found acting rapidly, hurriedly, and with 
a rhythm unfavourable for observation. Second sound not di- 
stinct. The experiments intended were two, viz., stopping the 
mitral valves by an interposed blunt hook introduced through 
auricle, or by a screw-shaped wire similarly admitted ; but owing 
probably to profuse haemorrhage, the first sound was not su& 

VOL. IX. 1840. o 



194 REPORT — 1840. 

ficiently normal for that experiment, and the second experi- 
ment was made, viz. — 

S. 1. Glass tubes drawn out at one exti'emity were pushed, 
with a rapid rotatory motion, into the auricle and venti-icle of 
left side, and the column of blood observed. That in the auricle 
gave no satisfactory result, owing to sanguineous exhaustion 
apparently, and the consequent insufficient distension in dia- 
stole, and slight amount of contraction in systole in the auricle. 
But this much was noted, viz., that a very short column that 
filled the drawn out part, was not drawn in diastole, yet 
neither was it very strikingly lengthened in systole. The ven- 
tricle gave better results, viz., a column rose rapidly by suc- 
cessive stages, rising some lines at each systole, and continuing 
almost stationary at each succeeding diastole, and at length 
overflowing the tube and pouring over in large drops at each 
systole. 

S. 2. The friction between the heart and pericardium in 
systole and diastole of auricles and ventricles ; the tension and 
jerking motion upwards in systole ; and softening and subsidence 
in diastole of the parietes of the ventricles : the abrupt jerking 
over the orifices in systole, followed by subsidence in diastole ; 
the shortening of the diameters lengthwise, and transversely 
in systole ; the immediate succession as by a continued undu- 
latory motion of the ventricular systole to that of the auricles ; 
the sensation of an undulation from fundus to apex on the ven- 
tricles ; the dimpling in systole of the left auricle (which only 
was observed); and the equality, post mortem cordis, of the two 
ventricles ; — all those former observations were repeated, and 
former results confirmed. 

Observation XVI. 

S. 1. The second animal's heart when exposed was acting 
with more regularity than the former, and the blunt hook and 
screw were successively tried. In each case material modifi- 
cations of the first sound were repeatedly produced by the in- 
terposition of the instrument between the valves in left interior 
opening ; but the modifications were not constant : and in no 
case was there any attempt made to impede the right interior 
valves. This much however was noted, that on several occa- 
sions the interposition of the instrument was followed by mur- 
mur in the mitral opening with the systole, and by a more ob- 
tuse character of the first sound, and particularly by a want of 
sharpness of definition at its commencement. But it is to be 
added, that considerable irregularity existed for the greater 
part of the time in the sounds, viz., the first sound seemed 



ON THE MOTIONS AND SOUNDS OF THE HEART. 195 

sometimes, and without apparent cause, more obtuse than 
others, and more short and abrupt, and the second was often 
wholly wanting or too indistinct for observation. 

S. 2. Further, there was observed a feeble dull sound, very 
short and rapid, synchronous with the left auricular systole, 
and somewhat anterior to the ventricular hardening, and up- 
rising, but scarcely separated by any distinct interval from the 
ventricular sound, and rather continued into it in a manner re- 
sembling the apparent passage of the auricular systole into 
that of the ventricle. 

S. 3. The glass tubes were in this experiment introduced as 
before, with similar results. Nothing striking occurred in that 
passed into the auricle, but a very short column being obtained, 
and that nearly stationary, owing probably to the auricle having 
been penetrated in several places by the hook and screw so as 
to suffer escape more readily by the other orifices. But the 
ventricle gave like results as in the former case, viz. a column 
rising in systole, stationary in diastole, and at length reaching 
the upper end so as to overflow. All the previously observed 
phaenomena of the motions of the auricles and ventricles, in 
themselves and with respect to each other, and with respect to 
the pericardium, were confirmed on this subject, so that the 
description of those given under the head of the former expe- 
riment of this day, themselves but repetitions of former obser- 
vations, must be considered to apply to the normal condition 
without any important restriction or qualification. 

Observation XVII. 

July 26th. — Phcsnomena : Dog — Distension to hardness of 
auricles during a torpid and as it were semi-paralytic state of 
ventricles ; — results of a prick in left auricle ; — proofs of active 
nature of auricular systole, and of negative character of ven- 
tricular and auricular diastole ; — of venous regurgitation du- 
ring auricular systole, and of equal size of both ventricles, 8^c.; 
— confirmation of other former observations. 

Subject, a Mastiff-terrier eighteen months old, poisoned 
— with prussic acid. 

S. 1 . Heart acting regularly but rather feebly, though large 
and muscular; much distended and on both sides equally. 
Left ventricle and auricle both much dilated and the auricle 
quite tense with blood, so that the appendix could not contract 
for some time until a prick was made in it, when a jet was ob- 
served coincident with the systole. Some observers thought 
the jet synchronous with the systole of the ventricle ; but on 
placing the fingers in contact with the sinus and fundus ven- 

O 2 



196 REPORT— 1840. 

triculorum together, it was plain that the jet coincided with 
the auricular systole, and preceded by a fraction of a second the 
ventricular systole. During the diastole of the auricles a slight 
shortening of the column, as from diminished impetus from be- 
low, occurred, and again, in auricular systole, a sudden length- 
ening of the column, to be followed again by a shortening in 
diastole. 

During the systole of the ventricles immediately succeeding 
that of the auricles, and without distinct interval, no increase 
of the jet or column occurred, and during the diastole of the 
ventricles no subsidence, but simply a shortening, as before 
described, immediately after the auricular systole. 

During great part of observation of the jet the left auricle 
was tense and hard almost to the finger, and nearly immove- 
able, and the ventricular action was dull and feeble, and the 
ventricles themselves were not fully emptied in systole, the 
heart appearing to have suffered considerable torpefaction 
from the poison. 

S. 2. A glass tube was introduced into the left auricle and 
ventricle in succession, but a clot soon forming, owing to es- 
cape of soda solution during the rotatory motion by which the 
glass was first introduced, no very decided result was obtained. 

S. 3. After the ventricles had become very feeble and even 
the left aui'icle become comparatively inert, some energy of 
contraction was observed in the right sinus, and with each con- 
traction a wave of regurgitation down the vena cava inferior, 
viz. a diastole of the vein immediately preceding the ventricu- 
lar contraction and coinciding nearly with that of the auricle, 
and followed by a systole coinciding with ventricular contrac- 
tion and auricular diastole. The auricles at no time acted with 
sufficient energy to promise any result from traction by a string, 
or to yield distinct sound in systole, owing to an extreme dis- 
tension of the cavities, attributable to torpor of the muscular sub- 
stance and rapid and copious supply of blood from the veins. 

S. 4. Tlie ventricles after death seemed not to differ mate- 
rially in size, having been cut out before complete death, and 
allowed to contract. 

S. 5. Several previous observations confii'med on this occa- 
sion, viz. as to rhythm of motions and cavities ; viz. auricles and 
ventricles respectively acted exactly together, and the former 
immediately before the latter, and without distinct interval, 
but as by continued undulatory motion ; elevation of central 
pai'ts of ventricles in systole and subsidence in diastole ; fric- 
tions of the pericardium double with each pair of cavities, viz. 
both in systole and diastole. 



ON THE MOTIONS AND SOUNDS OF THE HEART. 197 

Observation XVIII. 

Phcenomena : Tubes introduced into hearfs cavities; results ; 
— confirmations of former observations as to rhythm, pericardial 
frictions, changes of shape in the heart, 8fc., Sfc; compara- 
tive sizes of ventricles . 

July 30th. — Operated on a Dog between one and two years 
old by prussic acid. Heart acting feebly, with the normal 
rhythm however ; the cavities considerably dilated. 

S. 1. Glass tubes containing strong solution of carbonate 
of soda, secured during the introduction by corks temporarily 
fixed in the wide end, were introduced by a rapid rotatory mo- 
tion into tbe right ventricle and auricle. Owing apparently to 
awkwardness in the manipulation, the result was not through- 
out uniform to the eye ; but the general character of what was 
observed was this: Columns of blood rose into the tubes in 
every case, and were perceived to overflow in each case with a 
slight jet in the systole of the cavity penetrated, and a slight 
subsidence in the diastole. At one time, for a minute or two, 
without interruption, the tubes were observed to overflow 
steadily together, one being in left auricle and the other in right 
ventricle, each having a slight jet, or upward undulation, in the 
systole of the cavity containing it. This experiment was com- 
paratively very striking, owing to the great difference in colour 
of the two streams, viz. scarlet, and deep crimson or purple. 

During the whole observation nothing occurred suggestive of 
impulse, except of the impulse upwards of the systoles of cavi- 
ties, and the slight gravitation or subsidence in diastole ; and 
this latter, though often very distinct in each tube, was some- 
times quite imperceptible in either. No motion downwards in 
the tubes, such as suction would explain, was observed. 

S. 2. After the observation the heart was cut out, and the 
left ventricle appeared rather larger than the right. 

S. 3. The rhythm of the motions of the cavities ; the auri- 
cular and ventricular double frictions of the pericardium ; the 
jerkingupwards of the fundus and central parts of the ventricles 
in systole ; the shortening in systole ; the stationary state of the 
heart amid all its changes of size and shape ; the subsidence of 
the central parts and fundus in diastole, &c., &c., were noted 
to agree with former observations. 

Observations XIX. and XX. 
Aug. 5. — Operated by woorara on a Donkey two or three 
years old. Operation tedious, owing to strength and resist- 
ance of the animal. Also on a Dog. 



198 REPORT — 1840. 

Phcenomena : Donkey — Negative character of diastole. 

Dog — Apex cordis threaded and held tense in the direction 
of the mesial plane of the subject. Results : change of shape 
and size of the heart in systole and diastole, and visible mo- 
tions ; — glass tube passes into cava inferior; results; — columnce 
carnece and 23cirietes electrified ; results ; — cavities compared 
post mortem and found equal. 

S. 1 . Glass tubes introduced into the left ventricle at fundus 
and apex, and in each a column rose and at length overflowed, 
having a slight subsidence at each diastole, and sudden eleva- 
tion at each systole ; but no well-marked difference between the 
times of rise and fall in the tubes was detected. 

S. 2. The heart acted for some time with considerable energy, 
notwithstanding great haemorrhage, but soon failed after being 
perforated. The heart was then cut out while yet contracting 
vermicularly, and electricity was applied so as to permeate the 
columnae and parietes, but no satisfactory action was obtained. 
The cavities of the heart had been for some time much dis- 
tended, from loss of irritability before excision. 

Observation XX. 

A Terrier-dog, stout though small, was then stunned by a 
blow on the head ; the chest was rapidly opened, and artificial 
breathing estabhshed. 

S. 1. The apex cordis was then threaded, and at each sy- 
stole a pull at the chord was observed, followed by relaxation, 
and the tension and relaxation of the string alternated ; the 
former coinciding with systole, and the latter with diastole. 

{Note. — The string was drawn in the line of the longitudinal 
axis of the heart.) Dr. Boyd at one time kept the string firmly 
extended and permanently tense, by holding his hand as far 
away as the string would allow, for a short space, and then 
maintaining his position, but relaxing his hold so as to allow 
the string liberty to slide between his fingers when drawn away; 
and the result was, that before the experiment was suspended, 
an inch or more of the string appeared to have passed between 
his fingers, one eighth of an inch at least being pulled through 
at each systole. 

S. 2. After this observation had been made and repeated to 
the satisfaction of all parties, the heart acted still with much 
vigour, and both sounds were distinctly audible, notwithstand- 
ing great loss of blood. Also the diminution of the horizontal 
transverse and of the longitudinal diameter, and the increase 
of the vertical transverse diameter, with sudden bulging up- 
wards of the fundus and central parts, were very plain to the 



ON THE MOTIONS AND SOUNDS OF THE HEAllT. 199 

eye in systole ; — while in diastole the subsidence of the central 
pai'ts, with sudden increase of the horizontal cross diameter and 
of the long diameter, were equally striking. No tilting of the 
apex as an independent part was noted, nor any other motion 
than such as might be explained fully by the fixity of the 
fundus through the vessels, and the sudden increase of the 
cross vertical diameter in systole, causing an elevation of the 
longitudinal or central axis, which was most sensible at the 
apex or free extremity. 

S. 3. A glass tube was introduced into the cava with the 
termination directed towards the diaphragm, when a column 
of blood rose gradually without any jet until it reached the 
upper end nearly, when it ceased to advance, but continued 
stationary for some time, and at length receded slovvly towards 
the middle of the tube. No sudden motion either upwards 
(as ex. gr. by auricular contraction) or downwards (as by dia- 
stolic suction) was observed. A gradual partial subsidence in 
the tube then followed, owing apparently to failure of impul- 
sive force in the moving powers of the venous circulation. 

S. 4. The heart was then cut out while yet contractile, and 
irritated by electro-magnetism and by pricking with scalpel, 
and to the satisfaction of every one present the columnae carnese 
were observed to contract and relax coincidently with the 
parietds. 

S. 5. The ventricles were equal in capacity to the eye and 
hand post mortem cordis. 

Observations XXI. and XXII. 

August 8. — Two Dogs operated on ; one a stout terrier, the 
other a mongrel bitch, both eighteen months to two years old. 

Phcenomena : Second dog — Glass tube introduced into cava ; 
results variable, ivith probable causations of fluctuation; — au- 
ricles cease action first ; — columnce carnece irritated alternately 
with neighbouring parts ofparietes, and results ; — confirmation 
of former observations respecting the mechanism of heart's 
action and the equality of the cavities during life. 

In the former animal the operation failed, owing to not hav- 
ing established artificial breathing in time. 

In the dog the following results were obtained. Having 
been prepared by stunning and tracheotomy, with a view to 
artificial respiration, the heart was exposed, and found beating 
with energy, exhibiting the usual motions and sounds. 

S. 1 . A curved glass tube was introduced into the cava in- 
ferior, and immediately a column of blood was observed, which, 
after ascending some way steadily, and during several beats of the 



200 REPORT — 1840. 

heart, again descended also steadily and during several beats. 
After a few moments, the tube being held upright with care, 
and the lower opening of the tube being toward the abdomen, 
and pressure being made on the tube through the parietes of 
the veins, a column of blood ascended slowl)' and steadily to 
the top of the tube and poured over at the top. Again, press- 
ure being withdrawn from the cava, fluctuation occurred, viz. 
irregular ascents and descents of the column, gradual and slow, 
and extending each of them over several beats of the heart, 
there being perhaps as many as half a dozen of each to each 
minute of the time they lasted. At no time was there any sud- 
den elevation or subsidence of the column, such as the auricular 
systole or ventricular diastole might be supposed to produce, 
supposing the latter to include suction towards the ventricles. 
The variations of level observed in the tube could be referred 
with any probability to nothing obvious, except the convulsive 
agitation of the right thorax, which was intact, and which 
heaved and collapsed violently for a short time, owing to a 
partial recovery of the animal from the stunning blow during 
the operation, in consequence of haemorrhage and artificially 
sustained breathing. The tube was then introduced into the 
cava superior, and a column was observed in the whole length 
of the narrow part of the tube, and nearly an inch in height, 
and this column suffered no alteration either in systole or dia- 
stole. The shortness of the column in this case was owing ob- 
viously to exhaustion of the vascular system, or insufficiency 
of blood and of vascular tension. There was not any respira- 
tory effort during this last observation. 

S. 2. During this last observation (on the cava superior) the 
unusual appearance was observed of complete quiescence nearly 
of the auricles, whilst the ventricles continued to act with con- 
siderable energy. The early death of the right auricle might 
be referred to withdrawal of supplies from the cava inferior 
especially ; but that of the left auricle is not easily accounted 
for, since insufflation was duly persevered in. 

S. 3. The heart was cut out while yet contractile, and the 
columnae carneae of the right ventricle were observed to act 
accurately with the parietes, whether the stimulus were applied 
to the former or latter only. The columnge of the left ventricle 
were become insensible to stimuli, and the parietes nearly so 
before the left was laid open for observation. 

S. 4. The elevation of the central cardiac axis, and espe- 
cially of its free extremity, viz. the apex cordis, was very con- 
spicuous in systole, and the opposite motions in diastole. Also 
the flattening and lengthening of the ventricles in diastole, and 



ON THE MOTIONS AND SOUNDS OF THE HEART. 201 

rounding and shortening in systole. And after opening the ven- 
tricles the left seemed the larger of the two. 

The wave-like motion, or sensation as of an undulation from 
fundus to apex in systole, was very distinct. 

Observation XXIII. 

August 24. — A Dog (bull-dog terrier), one to two years old, 
stunned, and chest artificially inflated. 

Plicenomena : Residts of threading different parts of the ven- 
tricles, and at the same moment pressing the threaded parts 
with the finger, and pulling at them by means of the thread, 
showing the mechanism of the hearts throb ; — rhythm of cardiac 
and aortic pulsations ; — results of introdttcing a tube into the 
cava ; — respiratory suction ; — venous regurgitation in systole ; 
— phcenomena of the hearfs action out of the body both as to 
motions and sounds. 

S. 1. The heart was laid bare and a thread was passed 
through the apex cordis, and a second through the parietes 
nearly over the mitral orifice, and traction was exerted on each 
string in a direction outwards, and away from or vertical to the 
point of insertion, and the result was that in each systole each 
string was felt to be pulled and rendered tense, and to become 
lax in diastole. At the moment of tension in each chord the 
finger was placed on the point at which each respectively had 
been introduced, and the result was a double sensation, viz. 

1. That of traction in the chord, indicating contraction of the 
heart and mutual approximations of its extremities, and, 

2. that of outward impulse in the point of the parietes under 
the finger (indicating, as the Reporter conceived, the undulation 
of the blood reacting against the compressing parietes of the 
ventricles). 

S. 2. The attachments of the vessels or muscular parts in- 
serted into the roots of the arteries, especially the pulmonary 
artery, were observed very distinctly to approximate shghtly 
towards the apex in each systole, and to recede from the apex 
in diastole. 

S. 3. A barely perceptible difference in time was detected 
between the systole of the left ventricle and diastole of the 
aorta — no distinct interval however. 

S. 4. A glass tube was introduced into the lower cava, and 
a column of blood obtained, which oscillated frequently, but 
not in accordance with the heart's motions. These oscillations 
were attributable (the Reporter conceived) to ii-regular, spas- 
modic, respiratory eflPorts, occurring in the right side of the 
chest, which was still air-tight, the mediastinum being still 



202 REPORT — 1840. 

intact. The oscillations were sometimes short, and rapidly 
succeeded to each other with a rhythm not differing greatly 
from that of the heart, hut at other times were protracted 
through several heats of the heart, viz. an ascent continued 
for several seconds successively, followed by a descent in the 
tube of similar duration. 

S. 5. The pulsation of the veins was very distinct to the 
eye in systole, in both the pulmonary veins and cava ; but 
whether owing to the auricular systole exclusively, was not 
examined into with sufficient care. This much was ascertained, 
that the visible venous action was a diastole coinciding with 
the commencement of the general action of the heart, and fol- 
lowed immediately by a systole. Neither diastole nor systole 
of vein seemed gradual, but abrupt and almost instantaneous. 

S. 6. A heavy curved knife was placed on the left ventricle 
and held erect between the fingers, so as to allow motion up- 
wards or downwards, and the result was as in former experi- 
ments, an elevation by sudden heave upwards of the knife in 
systole, followed by a subsidence in diastole with depression 
of the surface. 

S. 7. The heart was cut out while still beating, and con- 
tinued to beat in the hand regularly, with normal rhythm, for 
a minute or two, and notwithstanding being shifted from hand 
to hand amongst three observers. The first sound was very 
distinct during the whole of the time, but less sharply defined 
at the commencement. It wanted likewise the jerking motion 
over the auri-ventricular openings, and the strong eccentric 
impulse or upward heaving in systole, and strongly-marked 
subsidence of the ventricle in diastole. The concentric 
motions and general rounding and shortening in diastole were 
very distinct. There was no second or diastolic sound. When 
cut open, the coluranae carneas were seen to act along with the 
parietes. 

Observation XXIV. 

August 26 and 28. — Repeated the experiment on the coii' 
traction of the abdominal muscles, as productive of a soundj 
resembling the systolic sound of the heart, in the presence of 
Dr. Edwin Harrison, Dr. Hamilton Roe, Mr. Phillips, F.R.S., 
Mr. Gulliver, F.R.S., and Dr. Robert Boyd. 

The instrument employed was the flexible ear-tube or ste- 
thoscope, with which only the experiment is satisfactorily 
practicable, on account of the strong impulse attending the 
contraction, and the difficulty of distinguishing the acoustic 
from the tactual sensations it occasions. 



ON THE MOTIONS AND SOUNDS OF THE HEART. 203 

The end of the instrument was placed in mediate contact 
with the abdominal parietes, and held firmly down upon the 
surface, with the intervention of a shirt and thick flannel 
under-vest ; a strong and sudden expiratory effort was then 
made (in the manner described in the First Report of the 
London Committee) with the mouth and nostrils closed, so 
that a strong vibratory action, ending in firm tension of parietal 
muscles, was sensible to the subject of observation (the Re- 
porter), and likewise to the observers, and with this result, 
that a single loud, obtuse, abrupt, short sound was heard, and 
thought by every gentleman to resemble, more or less, the 
systolic sound of the heart. 

S. 2. The same expei'iment was repeated, with the addition 
of several folds of a silk handkerchief to the intervening sub- 
stances ; and again, with a double fold of cloth and silk like- 
wise, in addition to the under-clothing above named, but 
without any important difference of result. 

S. o. Hard substances also were interposed above the 
under-clothing, viz. a common framed school slate, and small 
bound books of different sizes ; but no important difference 
was observed, except with the slate, through which the sound 
was considered to be decidedly less distinct than in any other 
form in which the experiment had been tried. In all these 
trials pains were taken to keep the cup of the stethoscope in 
accurate contact all round, through the substances interposed 
with the abdomen ; and that was easily effected by the use on 
the part of the Reporter, who was the subject of experiment, 
of both hands at once in maintaining equable pressure. 

It is proper to mention, that several observers agreed in 
stating that similar sounds occurring to show in the cardiac 
region, would be referred by them to the systole of the heart 
without any hesitation. 



Conclusions from both Series for 1838-39 and 1839-40. 

Motions. 

1st. That the order of the motions of the auricles and 
ventricles is by continuous succession rather than by alter- 
nation of actions. The auricles contract abruptly after the 
Rest or pause, and the ventricles immediately after the auricles, 
without any distinct interval between the successive systoles. 
And the diastoles of the cavities follow in somewhat similar 



204 REPORT — 1840. 

order, viz. the auricular diastole coinciding with the ventri- 
cular systole, and continuing after it ; the true Rest or pause 
being constituted by the diastole of the auricles and ventricles 
together, and in reality ceasing on the recurrence of the auri- 
cular systole. This rhythm of the motions seems to be uni- 
versal and common to cold- and warm-blooded animals. The 
only exception known to the Reporter from books or observa- 
tion, seems apparent rather than real, viz. an alternation of 
action, such as noted by Lancisi, for example, in the chick in 
ovo, and by several observers in cases of very rapid cardiac 
action. In such cases the diastoles have been so hurried and 
short, (owing no doubt to very rapid and copious influx from 
the veins,) that the systoles have been approximated to each 
other, and the intervening Rests have been apparently sup- 
pressed, and an apparent true alternation of systoles and dia- 
stoles without intervening Rest has been produced, 

2nd. That the visible systolic and diastolic motions are first 
perceived at the bases or fixed parts of the cavities, viz. in 
the auricles at the sinuses, and in the ventricles at the fundus 
cordis ; and that the apices of the auricles and ventricles (or 
free parts) are brouglit into full action after the other parts, 
and only just before the supervention of the opposite and next 
succeeding condition of the cavities, whether that condition be 
systole or diastole. 

3rd. That in systole the heart is diminished in all directions 
(except only in such regions, or parts of the organ, as may 
have been previously collapsed or compressed during the un- 
resisting flaccidity of the diastole), and that its long axis in 
particular is strikingly and invariably shortened. 

4th. That the normal systole of the auricles is energetic 
and almost instantaneous, and quite universal, the manifesta- 
tions of contraction in the appendix succeeding to those of 
contraction in the sinus, by a very minute interval ; and that 
the auricular diastole is gradual, continuous, and wholly pas- 
sive, and is effected by an influx of blood from the cava pro- 
gressively distending the cavity from sinus to apex, and from 
the termination of one systole of the cavity to the commence- 
ment of the succeeding one. 

5th. That the systole of the ventricles is gradual in its 
development, and complex in its phaenomena ; that those phae- 
nomena are partly attributable to contraction in the muscular 
parietes, and partly to resistance on the part of the fluids. 
By the muscular contraction the heart is made to compress 
the blood, which resists in all directions alike, and thrusts out 



ON THE MOTIONS AND SOUNDS OF THE HEART. 205 

the depressed or collapsed parts of the ventricles, and favours 
the systolic shortening of the organ, and the closure of the 
auri-ventricular valves ; and this reaction of the fluids mainly 
contributes, under various circumstances, to cause the motion 
that has been described as tilting of the apex ; this tilting 
being principally, if not exclusively, a result of the elevation 
of the long axis of the heart in systole, owing to the assumption 
of a convex or globular form in the body of the organ, instead 
of its superiorly and inferiorly compressed state in the previous 
diastole. 

And the ventricular diastole or dilatation is wholly passive, 
exerting no influence over the venous current or arterial valves, 
and is effected by a rapid influx of blood from the veins, com- 
mencing at the moment of relaxation of the ventricles, and 
continuing until their succeeding systole, and reinforced imme- 
diately before the latter action by an abrupt discharge from 
the auricles. 

6th. That the pulsations of the veins are of two kinds, at 
least in some animals, viz. both active and passive ; and the 
latter or passive pulsations (which, on the authority of Haller 
especially, may be held to exist in all animals), are attributable 
to reflux from the auricles in their systole. 

7th. The precordial throb or pulsation is caused, imme- 
diately, by the undulation of the blood in its resistance to 
sudden muscular compression in the systole of the ventricles. 
This reaction of the fluids is first perceived about the fundus 
of the ventricles, and last about the apex, towards which it 
seems to be propagated by a continuous undulation from the 
fundus with extreme rapidity. In consequence of this re- 
action of the blood, the heart's sides are rendered convex, 
instead of compressed or flattened as in diastole, and are, in 
the middle parts more especially, heaved outwards ft*om the 
central axis abruptly and with great force. Thus on all parts 
of the surface of the organ an impulse is felt in systole, which 
is greatest there, where, in addition to passive flaccidity of 
walls, there has been collapse in the diastole (viz. the central 
parts), and which is least where such collapse has previously 
been wanting or slight (viz. the apex). This cardiac impulse 
is usually perceived, in the healthy subject, over the apex 
only, owing to its being absorbed and neutralized over other 
parts of the heart by an interposed thick mass of spongy 
lung. The heart does not oscillate on the aorta, or move to 
and fro in the chest from systole to diastole, and vice versa j 
nor does it suffer any changes in consequence of its own 
efforts, and exclusively of movements of the lungs and dia- 



206 REPORT— 1840. 

phragm, excepting in its shape and size, and in the thickness 
and tension of its pai'ietes, and the capacities of its cavities. 
The doctrine, that the prgecordial pulsation is caused by a blow 
received by the ribs, in consequence of the heart's "jumping" 
{aXfMa, Hippocrates) or "striking" against them (" pectus ferit," 
Harvey; " costam ictu percutit," Haller, &c. &c.), appears to 
be superfluous, with a view to explanation of phfenomena 
(notwithstanding the ingenious illustrations of the ancient opi- 
nion by Senac and Hunter), and to be substantially unfounded 
in point of fact. 

8th. That the arterial diastole or pulse, almost everywhere 
outside of the pericardium, perceptibly succeeds to the cardiac 
systole ; though near the heart, the interval between them is 
very brief, and to unpractised observers difficult to distin- 
guish. 

Sounds. 

9th. That the first sound of the heart depends partly, but 
in a slight degree, on the abrupt closure and transitory ten- 
sion of the auri-ventricular valves, which give to this sound its 
sharp, well-defined beginning; but that the first sound is 
mainly attributable to cardiac muscular tension alone, and that 
its prolonged dui'ation is probably owing to the progressive 
character of the normal systolic effort from fundus to apex ; 
and that this sound is probably, in no degree or condition, 
attributable to any blow or stroke of the heart against the 
ribs. 

10th. That the auricular systole is attended by an intrinsic 
sound resembling that of the ventricles, but more short, ob- 
tuse, and feeble. This auricular systolic sound is often diffi- 
cult of detection, even on the naked heart, and with tolerably 
vigorous action of the auricles, owing to its being, to the inex- 
perienced ear, absorbed in, or masked by, the immediately- 
succeeding and vastly louder systolic ventricular sound. 

11th. That the sounds of friction in pericarditis may, where 
well marked and under ordinary circumstances, be expected 
to be double at least, and they may be, not improbably, triple 
or more. In its systole, each cavity of the heart moves so as 
to cause a friction, in one direction, of its attached lamina 
against the adjacent free lamina of the pericardium; and in 
its diastole, a pericardial friction is caused by each cavity in 
an opposite direction ; and as the auricles move to and fro in- 
dependently of the ventricles, the normal pericardial frictions 
must be quadruple, or double with the auricles and double 
with the ventricles. If, therefore, those frictions were ren- 



ON THE MOTIONS AND SOUNDS OF THE HEART. 20/ 

dered sonorous by the interposition of any rough substance 
between the rubbing surfaces, (as lymph, for example,) and 
supposing the heart's actions sufficiently vigorous, under ordi- 
nary circumstances, we might anticipate with confidence a 
duplication of murmurs at least — one systolic and one dia- 
stolic ; and this must be the pi-incipal element in the acoustic 
diagnosis of pericarditis, since effused lymph may be of any 
thickness, consistence, extent, &c., and be situate on any por- 
tion of the heart's surface between its nearest part and its 
furthest ; and may therefore cause friction-sounds of the most 
variable seat, depth, and character. But, of course, another 
physical means of distinction of gi'eat importance remains, 
viz. the comparatively equable diffusion of the sounds of peri- 
cardial friction all around the place of attrition, rather than 
in any one exclusive direction. 

12th. The sounds of the structurally-healthy heart are much 
liable to modification, by deviations from the normal standard 
in tlie state of the fluids and in the order and force and equa- 
bility of action of the carnefe columnae, and other contractile 
parts governing or influencing the action of the valves, and the 
closure and opening again of the orifices of the ventricles ; 
and this dependence of the heart's sounds on conditions dy- 
namic or material, wholly excluding structural defect, is so 
considerable, that the second sound may for a time be very 
variously modified or masked by strange murmurs, or even 
apparently suppressed in consequence of changes in the solids, 
of a purely di/namic character, and caused by humoral defect, 
in consequence of haemorrhage or from the introduction of 
poison into the veins. And the first cardiac sound, though 
never wholly wanting during the active existence of the heart, 
may still, under similar circumstances to those referred to, 
present various abnormal features ; may, ex. gr., be as short as 
the second sound, or be attended or followed by anomalous 
murmurs, or be otherwise strikingly modified. 

13th. Other conclusions, more or less satisfactorily de- 
ducible, as the Reporter conceives, from the facts stated, are, — 
That the peculiar sounds occurring in pericarditis, and attri- 
buted to pericardial frictions, are not referable only to vas- 
cular turgescence or dryness, &c. of the pericardium, but to 
lymph effused by, and adhering to, that membrane, or other 
equivalent obstacle to the easy and noiseless gliding over each 
other of the adjacent parts of the pericardium. 

14th. That the ventricles are of equal capacity during life, 
and that the inequality usually met with after death is an illu- 
sion, as explained long since by Hervey. 



208 REPORT— 1840. 

15th. That the suction-influence upon the venous circula- 
tion, attributed to inspiration by various writers, is well 
founded. 

]6th. That the action of the long muscles, and more espe- 
cially those of the abdominal parietes, is attended with an in- 
trinsic sound. The notice of this fact by the Reporter has 
been rendered necessary in consequence of some attempts at 
verification, and some criticisms on an Experiment of the 
London Committee for 1S37-38, published in the last edition 
of Dr. Hope's very valuable work on the Heart. 

17th. That the sounds of the heart, like the motions, are 
governed by the same law in all warm-blooded animals hitherto 
examined, and probably in all kinds whatsoever in which car- 
diac sound occurs, viz. that the first sound in all animals is 
relatively longer and obtuser, and the second shorter and 
sharper ; — that those sounds are, as in the human heart, 
respectively systolic and diastolic ; that their causation like- 
wise follows the same law as those of man, the first sound 
being mainly muscular, and the second probably exclusively 
valvular ; — likewise, that there is the same causation and mutual 
relation of the cardiac and arterial pulsations. 

John Clendinning, M.D. Oxon. and Edinb., 
Fellow of the Royal College of Physicians, Vice-Pre- 
sident of the Royal Medical and Chirurgical Society, 
and Physician to the St. Marylebone Infirmary. 



209 



An Account of Researches in Electro- Chemistry . By Pro- 
fessor ScHOENBEiNj of Basle. 

The British Association for the Advancement of Science at 
their last meeting in Birmingham, honoured me with the char-e 
to undertake a series of experiments, with the view of extend- 
ing the hmits of our knowledge on the connexion which is sun, 
posed to exist between electrical and chemical phenomena. 
Ihe memoir which I now take the liberty to lay before the 
Association contains an account of the results of my late inves- 
tigations, many of which may perhaps appear as not immedi- 
ately bearing upon the subject in question; but I think them, 
nevertheless, closely connected with it. I must, however, not 

pHshed'' ^^^'' "'^ *^'^ '' '^'" "^^'"^ ^^' ^'""^ ^""^S ^^^o"^- 

It is familiarly known, that a peculiar odour, resembling that 

of phosphorus, IS developed whenever common electricity 

passes from metallic or any other conducting points into at- 

Ivsknf w t T 'l^.u°"' '' disengaged during the electro- 
JXf of wa er, though there can be no doubt that, besides my- 
self, more than one philosopher has observed that ph«enomenon. 
The complete Ignorance in which we still remain of the true 
cause of the electrical smell, and of the appearance of the latter 

cannnt';"rr'""-f 'l^?''"^"^^^ ^° ^^'^^^^ f™- each other 
tdnnot fail to excite scientific curiosity to a high decree and 

stimulate philosophers to employ all the'ir experfment! means 
and mental powers to clear up the mysterious phenomenon! 
My own endeavours to solve the problem have been manifoW 
and for a long time were fruitless; at last, however, suc- 
ceeded in ascertaming some facts which promise to throw lio-ht 
upon the subject m question. Respecting the disengagement of 
the electrical odour during the electrolysation of wate?, as wel ■ 
as during the passage of common electricity from po nts hito 
atmosphei-ic air, my researches have led \o the'^Xdng 

electrolvLrrl!r 'T^\'^^^^' ^^\ appearance as soon as the 
fn. r ^ f- ^/ '''''*'''■ ^^^"'"^ ^"d continues to be perceived 
for some tune after water has ceased to be decomposed. 

trode onlv^ S ™.' '"'"" ^f P'"'^"'^^^ ^' the positive elec 
trode only, and under no circumstances whatsoever at the 



210 REPORT — 1840. 

negative one ; for when the gases resulting from the electro- 
lysis of water are received in separate vessels, the smell is 
perceived only in that which contains oxygen. 

3. The odoriferous pi'inciple can be preserved in well-closed 
vessels for a great length of time, whether mixed with oxygen 
or with detonating gas. 

4. The disengagement of the smelling substance depends — 
(a) Upon the nature of the positive electrode. 

(Z>) Upon the chemical constitution of the electrolytic fluid, 
and 

(c) Upon the temperature of that fluid. 

With regard to the circumstance mentioned under («), my 
experiments have shown that it is only well-cleaned gold and 
platina which are capable of disengaging the odoriferous prin- 
ciple. The more readily oxidable metals, as well as charcoal, 
do not possess that property at all. 

It is worthy of remark that iron, though acting (agreeably 
to my former experiments) like gold and platina when perform- 
ing the function of the positive electrode, does not permit the 
disengagement of the odour. 

As to the condition mentioned under (b), I have ascertained 
that the odoriferous principle is obtained from distilled or com- 
mon water when mixed with chemically pure, or with common 
sulphuric acid, with phosphoric acid, nitric acid, potash, and a 
series of oxi-salts. 1 could not get a trace of it from aqueous 
solutions of chlorides, bromides, iodides, fluorides, hydro- 
chloric acid, hydro-broraic acid, hydriodic acid, hydro-fluoric 
acid, sulphate of protoxide of iron. If to the fluids (above 
mentioned), which permit the disengagement of the peculiar 
smell, small quantities of nitrous acid, iron vitriol, proto- 
chloride of iron or of tin are added, not the least portion of the 
odoriferous principle will be given out, however actively water 
may be electrolysed. With regard to the aqueous solution of 
potash, I have observed the curious fact, that the smell is some- 
times disengaged from it and sometimes not, the latter case 
occurring much more frequently than the former. I do not 
know yet the cause of that anomaly. 

Concerning the influence which temperature exerts upon the 
development of the peculiar smell, I have found that a fluid 
from which the odoriferous principle is abundantly disengaged 
at a comparatively low temperature, does not yield a trace of it 
when heated near its boiling point. I must not omit to state, 
that dilute sulphuric acid is the fluid best fitted for producing 
the smelling substance, and making the experiments which this 
memoir refers to. It sometimes happens, however, that even 



RESEARCHES IN ELECTRO-CHEMISTRY. 211 

in making use of that fluid, the disengagement of the odorifer- 
ous principle is either suddenly stopped or does not take place 
at all. In such cases, the surface of the positive gold or platina- 
electrode is not pure, i. e. it is covered with some foreign sub- 
stance ; and to cause the reappearance of the peculiar smell, it 
is necessary to clean that electrode, which, by my experience, is 
best done by washing it first with pure muriatic acid, and after- 
wards with distilled water. 

5. If some pinches of powdered charcoal, iron-, tin-, zinc-, or 
lead-filhigs, or of powdered antimonj^, bismuth, and arsenic, or 
some drops of mercury are thi'own into a bottle containing the 
odoriferous principle (mixed with oxygen), the peculiar smell 
disappears almost instantaneously. Iron and charcoal seem, 
however, to act more rapidly than the other substances men- 
tioned do ; gold and platina, when strongly heated, also destroy 
the smell. Small quantities of nitrous acid and aqueous solu- 
tions of proto-chloride of iron, sulphate of protoxide of iron, 
and proto-chloride of tin, being put into a vessel containing 
our peculiar principle, do likewise instantaneously annihilate 
the phosphorus smell. 

6. A gold, or platina plate, after having been kept only for a 
few moments within a vessel containing the odoriferous prin- 
ciple (mixed with oxygen), appears to be negatively polarized. 
To excite that polar state in the metals mentioned, it is a con- 
dition, sine qua non, 

(rt) That the surface of the plate of either metal be abso- 
lutely clean and entirely free from moisture. 

(Z») That the temperature of the metal be comparatively low. 
Heated gold or platina do not assume the negative polar con- 
dition. The current produced by such a polarized metal is of 
so short a duration, that it may be considered as instantaneous. 
Among the metals more readily oxidable than gold and platina, 
it is only silver and copper that are rendered negative by being 
put into an atmosphere of the odoriferous principle ; but the 
degree of polarity acquired by these metals is exceedingly 
slight. 

7. Gold and platina having been polarized in the manner in- 
dicated, maintain their peculiar condition for some length of 
time when placed in common air. I have found plates which 
had been exposed to the atmosphere, at least for a couple of 
hours, still perceptibly negative. 

8. A polarized stripe of gold or platina loses, almost instan- 
taneously, its negative condition, when plunged into an atmo- 
sphere of hydrogen. If the metal is kept in hydrogen longer 
than just required for destroying its negative polarity, it as- 

p 2 



212 REPORT— 1840. 

sumes, according to my former experiments, a positive con- 
dition. It will hardly be necessary to mention, that heat also 
destroys the polarity in question. 

9. Oxygen obtained by the electrolysis of water, and deprived 
of its peculiar smell by the means indicated under § 5, has alto- 
gether lost its power of rendering gold and platina negative, and 
is, in a voltaic point of view, as inactive as oxygen prepared in 
the usual way. 

Phcenomena of Polarization caused by common Electricity. 

10. A gold or platina plate, having a perfectly clean and dry 
surface, assumes negative polarity when exposed to the action 
of a positive electrical brush issuing from a metallic or any 
other conducting point. The longer the brush is playing upon 
the surface of the metal, the higher will be the degree of polarity 
acquired by the gold or platina. A small platina stripe, after 
having been exposed to the action of a brush produced by 
thirty turns of my electrical machine, deviated the needle of a 
delicate galvanometer by 60° ; sixty turns, under the same cir- 
cumstances, caused a deviation of 90°. It seems that the 
nature of the metal which performs the function of a point of 
emission also exerts some influence upon the degree of polarity 
acquired by gold and platina. Cceteris paribus, a point of 
emission consisting of gold caused a deviation of 170°, a point 
of brass only one of 60°. As to the metals (more readily oxid- 
able than gold or platina), I have only succeeded with silver 
and copper in polarizing them negatively by common elec- 
tricity. The degree of polarity acquired by the last-mentioned 
metals is, however, also exceedingly slight. 

11. The negative electrical brush produces exactly the same 
voltaic effects as the positive one does. 

12. A platina plate, polarized either by the positive brush or 
by the negative one, loses its electro-motive power when 
plunged only for a few moments into an atmosphere of hydro- 
gen. All the remarks made under § 8 also apply to the case 
in question. 

13. If gold or platina plates are connected with the prime 
conductor of an electrical machine, i. e. made points of emis- 
sion, they will not assume any polar condition, however long 
and lively a brush may have been issuing from them. 

14. Heated or moistened gold, or plathia plates, cannot be 
polarized by the electrical brush. 

15. If the points of emission are heated or moistened, the 
electrical brush issuing from them has no longer any polarizing 
power. It was impossible to excite in gold or platina even the 



BESEAKCHES IN ELECTRO-CHEMISTRY. 213 

slightest degree of negative polarity by holding these metals 
ever so long against a brush issuing from heated or wetted 
points. 

16. The electrical brush proceeding from heated or moistened 
points does not produce the well-known phosphorus smell. 
The easiest way of depriving the brush of its smell is to cover 
the point of emission with a piece of moistened linen. 

Now in what manner are we to account for the facts above 
stated, and what are the inferences to be drawn from them ? 

As to the smell being developed at the positive electrode 
during the electrolysation of water, we can hardly help drawing, 
from the experiments mentioned in the first section, any other 
conclusion than that it is due to some gaseous substance dis- 
engaged (conjointly with oxygen) from the electrolytic fluid by 
the decomposing power of the current. But what is the nature 
of that substance ? Is it elementary or compound ? With 
regard to its voltaic bearings, it exhibits the strongest analogy 
to chlorine and bromine ; of which bodies I proved, some time 
ago, that they possess, to a high degree, the power of negatively 
polarizing gold and platina. I have also formerly shown, that 
these metals lose again their negative polarity acquired under 
the influence of chlorine and bromine, when plunged into an 
atmosphere of hydrogen ; there is, consequently, not the least 
doubt that, as to its electromotive power, the odoriferous prin- 
ciple bears the closest resemblance to chlorine and bromine. 
Now, does not this great analogy between the voltaic properties 
of chlorine, bromine, and our smelling principle, speak in favour 
of the supposition, that these three substances belong to the 
same class of bodies, i. e. to those which Berzelius called 
' halogenia' ? If we take into further consideration the facts, 
(a) that most metals destroy the peculiar smell, that is, com- 
bine with the odoriferous principle in a direct manner, and even 
at a low temperature; (;6) that the said principle is not dis- 
engaged at the positive electrode, unless the latter be composed 
of gold or platina ; that is to say, of an eminently electro- 
negative metal ', (c) that the odoriferous body is not eliminated 
by the current, if the electrolytic fluid happens to contain a 
substance having a strong affinity for oxygen, for instance, sul- 
phate of protoxide of iron ; and {d) that our peculiar principle 
is always set free at the positive electrode, and never at the 
negative one ; I say, if we duly consider all these facts, we can 
hardly help drawing from them the conclusion, that the odori- 
ferous substance is a body very like chlorine or bromine. The 
odoriferous principle, however, may perhaps be nothing but a 
secondary result of the electrolytic action. Such is no doubt 



214 BEPOKT — 1840. 

possible, and indeed it was the first view I took of the case. 
The following reasons, howevei", seem to speak against the cor- 
rectness of such a supposition. As chemically pure water (or 
what we take as such), mixed with sulphuric, nitric, and phos- 
phoric acids, with potash and many oxi-saits, yields the odori- 
ferous principle, we must conclude that the latter proceeds 
from water, and not from the other substances. Now what 
secondary product does water allow to be formed at the positive 
electrode ? The oxygen being eliminated at the latter, might 
certainly combine with some water, and produce peroxide of 
hydrogen. But this compound is not gaseous at the common 
temperature, and its vapour is wholly inodorous. I have be- 
sides observed, that platina enveloped with a film of peroxide 
of hydrogen, is positive to common platina. From these facts 
it follows, that the odoriferous principle cannot be peroxide of 
hjalrogen. Or does another perhaps exist, consisting of hydro- 
gen and oxygen, and containing more of the latter element 
than the peroxide does ? Are perhaps even chlorine and bro- 
mine compounds of a similar description ? The peroxides of 
manganese, lead, and silver, exhibit the same voltaic properties 
as chlorine and bromine, both groups of bodies being emi- 
nently electro-negative. Such a strong analogy, does it not 
indicate a similarity as to their chemical constitution? I do 
not venture to answer any of these questions. The present 
state of chemical science does not yet warrant us to speak of 
chlorine and bromine as of compounds, and I shall therefore 
consider the odoriferous principle as an elementary body, and 
call it " Ozone," on account of its strong smell. 

Now if we take it for granted that ozone is an elementary 
substance, and knowing that it originates in water, we must 
conclude that this fluid is made up of two electrolytes, one 
consisting of hydrogen and oxygen, the other of ozone and 
some electro-positive body. When a current is made to pass 
through such a fluid, both electrolytic compounds are decom- 
posed, their anions, oxygen and ozone, being evolved at the 
positive electrode, their cations at the negative, one. As to 
these cations, we know well enough that one of them is hydro- 
gen. But is ozone also, like oxygen, united with hydrogen ? 
All the experiments I have hitherto made with the view of dis- 
covering in the gas evolved at the negative electrode something 
besides hydrogen, have led to negative results, a circumstance 
which seems to prove that ozone, as met with in water, is com- 
bined with hydrogen. 

I do not, however, yet consider this point as definitively 
settled. That (what we call) pure hydrogen is capable of ren- 



RESEARCHES IN ELECTRO-CHEMISTRY. 215 

dering gold and platina electro-positive, seems to me so extra- 
ordinary and so important a fact with regard to the chemical 
theory of galvanism, that I cannot but recommend it to the 
full attention of philosophers. Why indeed should a piece of 
platina, being surrounded with a film of hydrogen, and vol- 
taically associated with common platina, produce a current 
when plunged into pure water ? Which is the chemical action 
that possibly can take place under such circumstances ? Ac- 
cording to the present state of our chemical knowledge, it is 
very difficult, if not impossible, to give a satisfactory answer 
to that question. Has perhaps all the hydrogen hitherto pre- 
pared not been chemically pure, and does it always contain a 
principle still more electro-positive than hydrogen itself, that 
is, having a greater affinity for oxygen than hydrogen has ? 
Careful experiments alone can decide these important points. 

The fact above stated, that ozone is not developed at the 
positive electrode, unless the latter be either of gold or of pla- 
tina, is, in my opinion, very easily accounted for. These 
metals having, at the common temperature, very little affinity 
for ozone, do not combine with it, any more than they do with 
oxygen in the same circumstances, whilst the other metallic 
bodies readily unite with the odoriferous principle*. 

At a high temperature, gold and platina appear to be capable 
of combining with ozone f ; and this propei'ty seems to account 
for the. fact, that from heated dilute sulphuric acid, for instance, 
the smelling substance cannot be disengaged. It is, however, 
possible that ozone, in the moment of its being eliminated by 
the current, reacts upon the heated water, combining with the 
hydrogen of the latter. 

The fact that no ozone is set free if the electrolytic fluid 
happens to be mixed with some readily oxidable substance, 
with iron- vitriol, for instance, seems to depend upon a decom- 
position of water, the oxygen of the latter uniting with the 
protoxide of iron, and its hydrogen with ozone. The non- 
appearance of the latter is indeed very easily understood, if we 
suppose its action to be entirely analogous to that of chlorine 
and bromine. 

Before proceeding to the discussion of other facts, I must 
say a few words on the polarizing influence exerted by ozone 
upon gold and platina. In former papers I have endeavoured 
to prove, experimentally, that certain voltaic conditions which 
some metals (placed under given circumstances) seem to assume, 
are not to be considered as real modifications of those metals 
themselves (a view still maintained by some philosophers), but 
* See § 5. t Ibid. 



216 KfiPORT— 1840. 

as changes proceeding only from certain substances being in 
some way or other deposited upon those metallic bodies. If, 
for instance, platina becomes positively polarized in an at- 
mosphere of hydrogen, and negatively in one of chlorine or 
bromine, that metal itself does not undergo the least change 
with regard to its natural voltaic properties ; and it is only the 
film of hydrogen or chlorine that surrounds the metal, which is 
to be considered as the seat of the electromotive power, or as 
the cause of the polarity. Exactly the same remarks apply to 
the negative polarity which gold and platina seem to assume 
when put into an atmosphere of ozone. By a sort of capillary 
action that substance adheres to the metal, and the latter being 
voltaically associated with another piece of the same metal (in 
its natural state) and plunged into water, the latter will be acted 
upon by ozone just in the same manner as under similar cir- 
cumstances it would be by chlorine or bromine. The film of 
ozone covering the platina will unite with the hydrogen of 
water, and produce by that action a current. This current will 
last until all the ozone adhering to the platina sti'ipe unites with 
hydrogen, but the quantity of that principle being exceedingly 
small, the duration of the current cannot be long. 

Having fully developed my views on the chlorine and bro- 
mine circuits in the Philosophical Magazine (August, 1839), 
and everything said there applying to an ozone arrangement, I 
have no occasion to enter into further details respecting this 
branch of the subject. 

As to the depolarizing action which an atmosphere of hy- 
drogen exerts upon gold and platina when negatively polarized 
by ozone, it perhaps may depend upon the combination of the 
latter with hydrogen. In order to account for the disappear- 
ance of the polar state, it is, however, not necessary to pre- 
sume the taking place of such an action. As platina becomes 
positively polarized by hydrogen, and negatively by ozone, it is 
obvious that the opposite voltaic actions of these two elements 
must, mider certain circumstances, exactly balance each other. 

It is manifest that the facts considered throw a new light 
upon what is usually termed negative voltaic polarization. The 
results which I obtained some time ago on that subject are 
pretty generally known. They seemed to prove that the nega- 
tive polar state assumed by the positive electrode in water 
(holding oxi -acids dissolved) is due to a film either of oxygen 
or of peroxide of hydrogen. To the same cause I was inclined 
to ascribe the negative polarity excited in that portion of aci- 
dulated water which is near to, or in contact with, a positive 
electrode. From the facts above stated, it now appears that, in 



i 



RESEARCHKS IN ELECTRO-CHEMISTRY. 217 

both cases, the negative polarity results from the presence of 
ozone. Indeed water charged with that principle is negative to 
pure water, whilst the same fluid holding oxygen dissolved is, 
in a voltaic point of view, inactive to pure water. Water 
mixed with some peroxide of hydrogen bears to common water 
the same voltaic relation as zinc does to copper. Without 
having recourse to actual electrolysation, we may indeed pro- 
duce, by means of insulated ozone, all the phsenomena of nega- 
tive voltaic polarization, a fact which seems to prove the 
correctness of the explanation offered of the phsenomena in 
question. 

I also suspect that the peculiar condition of iron, or its in- 
active state, has something to do with ozone ; but for the pre- 
sent I cannot enter into that subject. 

It is now time to speak of the phsenomena of polarization 
produced by the agency of the electrical brush. On comparing 
them with those called forth by ozone, we cannot but perceive 
a strong analogy between both series of phsenomena. The very 
same metals which become negatively polarized by ozone, are 
brought into a similar state by the action of the electrical 
brush. The same conditions to be fulfilled, in order to polarize 
gold and platina by ozone, are likewise requisite to render 
these metals negative by the agency of common electricity. 
The negative polaritj' developed by ozone is destroyed by the 
same means by which we annihilate the negative polar state 
called forth by the brush. These facts are sufficient to coun- 
tenance the conjecture, that the cause of the negative polarity 
is in both cases the same, i. e. that it is a film of ozone sur- 
rounding the metals. I have stated (§ 16) that the brush can 
easily be deprived of its peculiar smell, and that by so doing 
the former loses its polarizing power. This fact clearly 
proves that it is not the electrical brush or discharge itself 
that excites in the metals exposed to its action the negative 
polar state, but the odoriferous principle accompanying the 
brush. This principle affecting our olfactory nerves precisely 
in the same manner, and also producing the same voltaic effects 
as ozone does, are we not entitled to infer that the smelling 
matter in the electrical brush and the odoriferous principle 
evolved at the positive electrode, are identical bodies ? It ap- 
pears to me that they are, and I do not, therefore, hesitate to 
ascribe the familiar electrical odour to ozone. 

But how does it happen that ozone makes its appearance, 
whilst common electricity is passing from the points of a 
charged conductor into the atmosphere ? To account for such 
a remarkable fact, we certainly must suppose that there is an 



218 REPORT — 1840. 

electrolytic compound present in the air, as well as we suppose 
one to be contained in water, and that the electro-negative con- 
stituent, or the anion of that electrolyte, is our ozone. The 
passage of electricity from the points of chai'ged bodies into 
the surrounding air being in fact nothing but the act of the 
restoration of a broken electrical equilibrium, or a current, it 
is not difficult to conceive how ozone is set free near the points 
of emission. Our supposed electrolyte being present in the 
atmosphere, requires only to be placed within the circuit of 
such a current in order to be electrolysed, or to have its anion, 
ozone, separated from its cation. If all these suppositions be 
correct, it follows that the electrolj^sis of our ozonic compound 
will be most vigorous where the emission of electricity is most 
abundant, and that consequently, at such a spot, the strongest 
smell of ozone will be perceived, and platina or gold acquire 
the highest degree of negative polarity. Now experiments 
prove that such is really the case. 

That the peculiar odour perceived when any terrestrial ob- 
ject is struck by lightning has something to do with ozone, 
cannot be doubted. We have been hitherto profoundly igno- 
rant of the nature of that odour, and everything said and 
conjectured about it by ancient and modern philosophers must, 
in my humble opinion, be considered as totally unfounded. 
We know the fact only, and nothing more. The smell pro- 
duced b)' lightning is usually described as being either sul- 
phureous or phosphorous. Twice in my life I had an opportunity 
to observe this odour, once in the church of my native place 
(Mezingen in Wurtemberg), many years ago, another time in 
my own house at Basle, only last summer. The second case 
being still fresh in my memory, I shall say a few words about 
it. The object struck by lightning was a small chapel situated 
on the middle of the bridge of the Rhine, and about 200 yards 
distant from my lodgings. Immediately after the stroke had 
taken place, not only my house, but also the houses of my 
neighbours, were filled with a bluish vapour, and a pungent 
smell was perceived. Six hours after the occurrence I entered 
into a parlour which had not been opened all the day, and I 
could still perceive the peculiar odour. My testimony is cer- 
tainly not wanted to establish the fact, that lightning always 
causes the disengagement of an odoriferous principle ; but I 
think that, on account of the great mystery which is still hang- 
ing over that phsenomenon, the number of observations and 
statements about it cannot be too much increased. The fact 
related offers, besides that peculiar interest, that the smell was 
perceived at a comparatively great distance from the object 



RESEARCHES IN ELECTRO-CHEMISTRY. 219 

struck by lightning. As far as my observations go, they in- 
cline me to consider the odoriferous gaseous substance set at 
liberty by the agency of lightning as ozone. Lightning being 
the same pheenomenon on a large scale as the electrical spark 
or brush is on a small one, and our supposed electrolytic com- 
pound penetrating the whole atmosphere, electrolysis must 
take place, and consequently ozone be disengaged to a con- 
siderable amount, as often as lightning crosses our atmospheric 
air. The assertion of some observers, that the odour is of a 
sulphureous kind, and the statement of others, comparing it 
vpith the smell of phosphorus, may easily be reconciled to each 
other ; for I have remarked that ozone, when somewhat con- 
densed, is rather pungent, whilst the same substance mixed up 
with a large quautity of air, possesses a phosphorus smell. It 
is well known that the generality of people call any pungent 
odour sulphureous. Hence, if it happens that the odoriferous 
principle set free by lightning reaches the observer in a con- 
densed state, he will describe it as sulphureous, but like phos- 
phorus when inhaled mixed up with a good deal of air. Hence 
it follows, that the nearer the observer happens to be placed to 
the spot where a stroke of lightning takes place, the more pun- 
gent will be the smell perceived by him. The property of pla- 
tina to assume negative polarity in a medium containing free 
ozone, seems to offer an excellent means to ascertain the pre- 
sence of that principle in the atmosphere. It appears, there- 
fore, to be desirable to make experiments on that subject, and 
to place, for that purpose, platina stripes (not being insulated) 
in elevated regions, particularly on days when thunder-storms 
are taking place. 

Before closing this paper, 1 must not omit to put a question 
of some importance. Does the electrolytic compound men- 
tioned exist in our atmosphere quite independent of its aqueous 
vapour, or is it (the electrolyte) carried into the air by the eva- 
poration of water ? It is a matter of course, that this question 
can only be answered by experiments, and I have not yet found 
time enough to make them. Supposing the electrolyte to be 
carried into the atmosphere by the evaporation of water, the 
electrical brush should not produce any smell when passing into 
absolutely dry air, and the quantity of ozone disengaged would, 
cceteris paribus, be proportional to the quantity of aqueous 
vapour present in the atmosphere ; i. e. would depend upon the 
hygrometric state of the latter. It is hardly necessary to say, 
that problems of the highest scientific importance would be 
raised, in case it should turn out that ozone can be produced in 
dry air. Be that, however, as it may, the ubiquity of our elec- 



220 RKPORT— 1840. 

trolyte can hardly fail acting a most important part in the 
household of nature ; and it is not impossible that the elec- 
trical phsenomena taking place within om- atmosphere, the real 
cause of which is still covered in dai'kness, are closely con- 
nected with the workings of our presumed compound. 

The fact of philosophers having not yet had the slightest notion 
of the existence of such a body is, I presume, no argument against 
its existence. If we suppose the electrolyte in question to be 
a substance closely resembling water in its chemical and phy- 
sical properties, and existing in the latter flviid as well as in the 
atmosphere, only in very small quantities, it is easily conceiv- 
able why its existence has not hitherto been observed. I 
readily allow, however, that many researches, many experi- 
ments, must still be made before we arrive at certain results, at 
complete certainty, regarding the subject of ozone. Convinced 
as I am of its great scientific importance, I shall not fail de- 
voting all my leisure time to its close investigation, and to 
sifting a matter to the bottom which promises to yield so rich 
a harvest of results. I should feel indeed very proud, if the 
British Association would honour me with the charge to pre- 
sent them an account of my researches next year. 

It would be not right if 'I did not expressly state, before 
finishing mj'^ paper, that I owe most of the results above men- 
tioned to a pile constructed upon my friend Mr. Grove's prin- 
ciple, an arrangement which cannot be too highly thought of. 

C. F. SCHONBEIN. 
Bale, August 2, 1840. 



221 



Second Report upon the Action of Air and Water, ivhether 
fresh or salt, clear or foul, and at various temperatures, 
upon Cast Iron, Wrought Iron, atid Steel. By Robert 
MalleTj M.R.I.A., Ass. Ins. C. E. 

140. Since my former report upon this subject was submitted 
to the British Association, as now printed in its Transactions, 
additional interest and importance has been given to every 
branch of the inquiry, as to the durability of iron under its 
various circumstances and conditions, by the rapidly-increasing 
introduction of iron vessels to navigation in the most difficult 
and lengthened voyages. 

Amongst the several problems of a strictly scientific cha- 
racter requiring solution before the use of iron ships for distant 
voyages, or their economic adoption, under any circumstances, 
can be pronounced certain, is the great question of their dura- 
bility as compared with those of timber; and it is hoped 
that the experiments made or in progress under the auspices 
of this Association, and about to be detailed, will render, in 
part at least, a satisfactory reply thereto. But, besides the 
desirableness of prolonging the existence of iron ships, it is 
of the utmost importance to prevent the formation of rust at 
all upon them under water, which, once produced, affords a 
" nidus" for the growth of marine animals and plants by which 
the ship's bottom is rendered foul, and her sailing qualities are 
greatly interfered with. These causes of foulness are found to 
adhere with the utmost obstinacy to the oxidized iron. It is 
part of our object to endeavour to find remedies for these 
evils. 

141. The present report contains the first set of tabulated 
results which I have obtained as to the amount and nature of 
corrosion of cast and wrought iron under several different con- 
ditions of exposure to the chemical action of air and water, 
whether of the ocean or of rivers, &c. And as this subject 
essentially consists of two distinct parts, or is to be viewed in 
two different lights, namely, as a chemical or purely scientific 
inquiry, and as a technical one, from which useful practical 
results are to be derived, and as some portions of it, viewed in 
the former light, are still under experiment, and likely to be so 
I for some time to come, I purpose, on this occasion, to reserve 
the purely scientific consideration of the subject, as far as pos- 



222 REPORT — 1840. 

sible, for a future and final report, and confine the present to 
the results and their modifying conditions which have already 
been obtained, and are of practical value and importance to the 
civil engineer, the iron founder, or the iron-ship builder. 

142, 1 proceed, then, to state the general nature of the ac- 
companying tabulated results of experiment. The first five 
tables contain the data and results of the chemical or corrodmg 
action of sea and fresh water on cast and wrought iron under 
five several conditions of experiment, continued during a period 
of between a year and thirteen months. 

It will be seen that these five first tables, so co-ordmate with 
each other as to form one connected and comparable whole, by 
which have been determined the relative rates of corrosion, and 
the absolute amount thereof, for eighty-five several sorts of cast 
and wrought iron, under each of the following conditions, viz. 
1. In clear sea water, at temp. 46° to 58° Fahr. 
II. In foul sea water, „ 46° ,, 58° „ 

III. In clear sea v/ater, „ ^ 115° „ 

IV. In foul river water, „ 36° „ 61^ „ 
V. In clear river water, „ 32° „ 68 „ 

143. During the period in which the several sets of speci- 
mens iiave been immersed, the five waters acting on them have 
been examined as to their physical and chemical properties. 

144 The water of No. 1, that of Kingstown Harbour, con- 
tains, in a cubic foot, 12661 grains of soUd matter, which 
analysed with precaution in the usual manner, had the follow- 
ing constitution reduced to per cent. : 

Chloride sodium 71*32 

Chloride magnesium 10-79 

Bromide magnesium 0-60 

Sulphate lime 4-87 

Sulphate magnesia 5*30 

Carbonate lime l'/3 

Organic matter 5*27 

Lots Q-12 

100-00 

I could not detect any chloride of potassium or carbonate 
iron said to be occasionally present in minute quantity in sea 
water. The amount of organic matter is very variable. It 
therefore appears not to differ much in composition from the 
waters of the British Channel, but considerably from those of 
the Mediterranean and the Atlantic Ocean, as given in the best 



ON THE ACTION OF AIR AND WATER UPON IRON. 223 

published analyses*. Its specific gravity is = 1027-80 • and 
100 cubic inches of the water taken from the surface contain 
in combination, 1-43 cubic inch of gas, which proves to be 
atmospheric air, with traces of carbonic acid, or about one 
volume in seventy. This water is beautifully pellucid, and 
free from suspended inorganic matter. Its boiling point in 
glass IS 214-5 Fahr., barom. 29-7 inches. 

145. The following table of the amount of saline contents 
ot sea water, from various localities, may be interestino- as 
bearing upon our subject : — ^ 

Table of Saline Contents in 1000 parts of Sea Water. Authorities. 

^'■*^^!^ ge^ 28-30 Marcet. 

Arctic bea sea water . . . 350 

North Atlantic 42-60 " 

Equator 39-20 " 

South Atlantic 4r'>0 " 

Mediterranean . . . . [ 39-40 Laurent 

Sea of Marmora 42-00 Marcet. 

rJlacK kSea 21-60 

Baltic ". Q.QQ 

'Dead Sea 335.00 

British Channel 35-50 Sweitzer. ^ 

^"'^^^^ 33-76 Mallet. 

146. One thousand volumes of sea water are stated, on the 
authority of Laurent, Bouillon, and Lagrange, to contain 62 
vobimes of carbonic acid. I have never been able to find as 
much. Dr. Marcet also states that ammonia is occasionally 
present m it. ^ 

147. The water of No. 2, or that of the foul sea water taken 
trom the mouth of the great Kingstown sewer, is found'full of 
putrid organic matter of a black and white colour, exhales an 
intolerable fcetor, and is permanently milky or opalescent. A 
cubic foot of It contams 1379-5 grains of solid matter at a 
minimum, and varies, up to the full saline contents of the sea 
water, according to the degree of dryness of the weather and 
consequent greater or less admixture of fresh water ^The 
water i?i situ constantly evolves bubbles of hydrosulphuric 
acid and pond-gas = (H, C), of which torrents^Bay be ob- 

Ire'thP i ''''""?. *''' T^ ^' *' ^^"'^^^^ ' ^^^ ^«"d constituents 
are the same as those above given for the sea water of the bar 
Dour, with a very variable proportion, however, of carbonate 
and sulphate of lime and of ^chloride of calcium,' derived from 
tne Iresh water which mingles with the salt. It holds, com- 
• Marcet, Laurent. 



224 REPORT— 1840. 

billed, one volume in thirty-six, on the average, of a mixed gas, 
consisting of 

Atmospheric air, 

Carburetted hydrogen. 

Hydro-sulphuric acid. 

Carbonic acid, 
the proportions of which vary at different times. The residue 
of the water very gently evaporated yields at times traces of 
phosphate of ammonia. Its boiling point is in glass = 213°*5 
Fahr., barom. 30*2 inches. Its specific gravity is = 1-02770 
at maximum found. 

148. The water from No. 3, or clear sea water, at 115° 
Fahr., is of course, in all respects, the same as the water from 
Kingstown Harbour, except containing less combined air. 

149. The water of No. 4, or that from the river Liffey, 
w^ithin the tidal limits, consists of a variable mixture of water, 
having the same constitution as that of Kingstown Harbour, 
with the water next to follow, or No. 5. It is alternately fresh 
and salt with the rise and fall of tide, and always foul ; much 
organic matter is suspended in it, and some extremely divided 
silex. It evolves hydrosulphuric acid and common air on 
boiling, and contains about one volume of these in twenty of 
water. One cubic foot of it contains, after filtration, 58r5 
grains of solid matter, Avhich consisted of 

Putrified organic matter 28*00 

Chloride sodium ......... 49-73 

Chloride and bromide of magnesium ... 6-10 

Sulphate h me 11*21 

Sulphate magnesia 3*00 

Loss 1-96 



100*00 
Traces of ammoniacal salts also are found, and of phosphoric 
acid or phosphates. Its specific gravity is = 1*00227, and its 
boiling point is in glass 212" Fahr., barom. = 30*1 inches. 

150. The last water, No. 5, or that of the clear stream of 
the Liffey, above the tidal limits, and above the city of Dublin, 
contains one volume in eleven of mixed gases, which are at- 
mospheric air and carbonic acid, generally in about the pro- 
portion — 

Air 94 cubic inches. 

Carbonic acid 6 „ 

100 



ON THE ACTION OF AIR AND WATER UPON IRON. 225 




consistin; Of "" ^''"'' "' '"''^ "^^"'^''^ 



Sulphate Jime 5'>-53 

Carbonate lime 24*44 

Carbonate iron ^.oo 

Chloride calcium \ g.gj 

Chloride magnesium 4-22 

Chloride sodium .... * 2-27 

^°^« '.'.'.'. 2-30 

100 00 
It gives uncertain traces of a free alkali, probably carbonate of 
soda derived m all probability from the beds of albite over 
which the river LifFey passes, a fact long previously not c'ed by 
?l4°S^ 'i '^^•'k^"' ^^' boiling-pci^,it of this water I 

winder andfui^mL"'"' ""''"'' ^"^ ^"'^ ^^'^'^^^^ ^'^-- 
nprlt?: f!l *^\^^*T "\^hich the various classes of iron ex- 
Rf! Tk'^ ""k T ^.^^'' i^in^ersed are now described ; and as 
the methods by which these experiments have been conducted 
the particular Objects in view and the precautions observed have 
been detailed in my previous report*, it will only be further ne- 
cessary to premise that— ^ xiuerue 
152. The corrosive action of air and water in the above con- 
ditions upon iron presents its effects in five characteristic states 
of oxidation or rust, on the surface of the metal varying with 
the nature of the cast iron, the mode of casting, &c. &c. These 
are referred to in column 13 of the tables of results, thenmnei ! 
clature of which it may be necessary to explain 

It IS unchangeable in all the tables, and embraces the follow- 

ng terms, which are thus explained. 1st, Uniform, or when 

the whole surface of the iron is found covered uniformly with 

a coat of rust requiring to be scraped off, and leaving a sinooth 

red surface af er it; 2nd, Uniform P., or uniform ^ith plum- 

scSin^T'fr 'h '"^^'''' ^? '^'""' ""^^^-^^3^ corroded on 
scraping is found in some places covered with plumbaginous 

?rdV ^'!"^ ^ I P^'¥^" ^"^^^'^^ «f ^^d and black after 
t , 3rd, Local, where the surface of the iron is found only rusted 

4th, Local Pitted, where the surface is found as in the last 
1840 * ^^^°''' ^ ^^ '" ^^' ■•" ^^P°'^' ^ -°- 



226 REPORT— 1840. 

case, but on scraping the rust off the metal is found unequally 
removed to a greater or less depth beneath it, so as to leave a 
pitted uneven surface ; 5th, Tubercular, where the whole of the 
rust which has taken place at every point of the specimen has 
been transferred to one or more particular points of its surface, 
and has there formed large projecting tubercles*, leaving the 
rest bare. 

In one or other, or some combination of these forms, every 
sort of iron, cast and wrought, wliich I have noticed, corrodes 
when exposed to the action of air and water, by which is meant 
water holding jiir in combination, such as all water at common 
temperatures found in nature does. 

153. The 12th column in these tables contains the amount of 
water, if any, absorbed by the specimen of iron. It was con- 
ceived possible, from some known facts f, that cast iron long 
under the pressure of water might from its porous crystalline 
grain absorb the fluid more or less like a sponge ; if so, it was 
necessarjr to know the amount of this as influencing the weigh- 
ings. Means were therefore taken to determine the point, and 
the tables show that in almost evei*y case no absorption has 
occurred; where it has, the result is to be attributed withoutdoubt 
to a minute " blow-hole," or cavity in the casting. 

It is certain, however, that under a sufiicient pressure, cast 
iron may be caused to absorb water or other fluids, and experi- 
ments are in progress to determine the conditions of this ques- 
tion, which is not without interest and utility. The difficulty of 
obtaining cast iron impermeable to fluids is M^ell known to the 
makers of hydravdic presses. 

154. The tables Nos. VI., VII. and VIII. reduce into a small 
compass the whole of the results of the preceding ones ; their 
own headings sufficiently explain their particular objects ; it 
is therefore only necessary here to make some general obser- 
vations on a few of the more striking results arrived at so 
far. 

155. On the average it will be seen that the metallic de- 
struction, or corrosion of cast iron, is a maximum in the clear 
sea water at the high temperatui-e of 115° Fahr. (y), and that it 
is nearly as great in the foul sea water (|3), while it is a mini- 
mum in the clear river water (e). 

156. The temperature is not higher in the first case than iron 
in works of engineering, or in iron ships is likely to be exposed 
to in different parts of the world, as the following data in- 
dicate : — 

* Report, § 49 to 59. f Rpport, § 37 to r)8. 



ON THE ACTION OF AIR AND WATKR UPON IRON. 22/ 

A thermometei' sheltered from radiation and 
on land does not rise, in any part of the 
globe, above + 114°-8 Fahr. 

One similarly situated on the open sea, 

no-where rises above + 87°' 8 

Lowest observed temperature on land . . — 58° 

Temperature of the sea in any latitude or sea- 
son, never rises above + 86° 

Nor has been observed lower than ... — 29° * 
At the mouths of tropical tidal rivers, or in lagoons, the tempe- 
rature of the water, however, may reach a much higher limit. 

157- I woidd here I'emark a cause of increased corrosive ac- 
tion, affecting castings, such as cast-iron piling, &c., at the 
mouths of tidal rivers, which has not, to my knowledge, struck 
previous observers. 

It is well known that the sea water, during the flowing of the 
tide, from its greater density, forces itself beneath the river water 
like a wedge, and slowly and imperfectly mixes with it, hence 
two strata, one of fresh or brackish watei", the other of salt 
water below it. Thus while engaged in a diving-bell survey of 
part of the bed of the river Bann, in the North of Ireland, last 
year, I found, during the flow of tide, the water strongly saline 
at the bottom of the river, and yet fresh enough to drink within 
three feet of the surface, the total depth of water being about 
25 feet ; and in the Proceedings of the Royal Society of Edin- 
burgh (April, 1817) will be found a paper by Mr. Stevenson, 
C.E., in which he describes analogous phaenomena as occurring 
at the mouth of the river Dee, at Aberdeen, in the rivers Forth 
and Tay, and at Loch Eil, where the Caledonian Canal joins 
the Western Sea. On taking water up at various depths at Fort 
William, he found the specific gravity 

At the surface = 1008-2, 
At 9 fathoms = 1025-5, 
At 30 fathoms = 1027-2, 
or completely fresh at top, and salt as the sea itself beneath. 
Now Becquerel has proved that a homogeneous metallic sur- 
face (a rod or wire for instance) exposed to the action of a fluid 
menstruum, M'ill assume a state of electrical tension, provided 
that the fluid in which it is immersed be of different density in 
two strata, i. e. of different corrosive power. In fact, the 
metal and the two layers of fluid constitute a voltaic pile 
of one solid and two fluid elements ; hence as one end of the 
metallic rod will be in a positive state with respect to the 
other, it will be corroded faster than the other. Now this 
* Annales de Chimie, xxvii., 432. 
q2 



228 REPORT — 1840. 

is precisely the condition of any casting reaching through a 
considerable depth of M'ater at the mouth of a tidal river. The 
water is salter below than above, the part of the casting im- 
mersed therein (the lower end of a cast-iron pile for instance), 
will therefore be in an opposite electric condition to that of the 
portion above, and the amount of corrosion of the positive ele- 
ment due to the kind of iron, and the state of the water, will be 
further increased or "exalted" by the negative condition of the 
opposite end, which will be itself in the same proportion pre- 
served. This principle extends to very many practical cases, 
as to iron plates, &c., partly immersed in a solvent fluid, and 
partly exposed to moist air, &c. ; and it suggests the importance 
of giving increased scantling to all castings intended to be so 
situated, to allow for this increased local destruction of material. 

158. In section (138) of my previous report, I stated the fol- 
lowing as important desiderata for experimental answers as 
touching the subject, viz., 

I. The rate of progression of corrosion in sea and fresh 

water, with reference to increasing depth. 

II. The comparative amount of corrosion in the same water 

at various temperatures, within the limits of climate 

and season. 

III. The determination of the relation between the saltness 

of water and its corroding eff"ects on iron. 
I am now enabled to state the law governing each of these 
conditions, as deduced experimentally. 

159. And first, with regard to depth : if water held in solu- 
tion or combination the same volume of air or oxygen (not 
constitutional) at every depth, then the amount of corrosive action 
of the menstrua on iron or any other metal standing in its rela- 
tion to air and water, at any given depth, will be to the amount 
of corrosion of the same iron at any other depth, inversely as 
the depth. This supposes the water stagnant, and that fresh 
supplies of combined air are derived from the surface, and not 
from a lateral current. It also only applies to moderate 
depths ; and it is possible that at veiy great depths this law 
might not hold true. 

160. We do not know with any certainty whether deep 
waters, or the ocean, contain the same proportions of combined 
air at all depths ; but within twentj^-four feet I have not been 
able to find any difference in the volume of combined air from 
that at the surface in either sea or river water. 

161. This determination, of course, will not apply where a 
constant supply of water, holding new quantities of combined 
air, is brought in laterally, as in a tide- way or river. In this case. 



ON THE ACTION OF AIR AND VVATKR UPON IRON. 229 

if the proportion of combined air be the same at all depths, it 
seems probable the corrosion will slightly increase with the 
depth ; but the matter is now under experiment. 

162. The second question, namely, at what temperature the 
corrosive action of water on iron is a maximum, has with each 
(sea and fresh water) two conditions, namelj^, when the water 
is combined with air, and when it is freed from it by boiling, or 
otherwise. 

163. In the first case, namely, in water and combined air, I 
find corrosion proceeds fastest in fresh water at temperatures 
varying between 175° and 190° Fahr. 

164. I find, further, that the rapidity of corrosion is in the 
direct ratio of the volume of combined air at any given tempera- 
ture ; and lastly, I have found, on slowly heating water holding 
air in combination from 60° Fahr. up to 212° Fahr., that the air 
is evolved most freely, and in greatest volume, at 190° to 195° 
Fahr. ; hence we at once perceive that the reason why the 
maximum corrosion of fresh water with combined air is between 
175° Fahr., and 190° Fahr., arises from this being the point at 
which the attraction of the water for the air is destroyed, or 
nearly so, and hence the latter left free to combine with the 
metal. 

165. If fresh water be deprived of all combined air, its cor- 
rosive action on iron ceases in toto in a close vessel ; nor does 
corrosion commence at a boiling temperature ; but if the vessel 
be open and very shallow, the heat even of ebullition does not 
prevent the absorption of air ; and oxidation, once commenced, 
goes on even more rapidly than at a lower temperature. 

166. Information is yet wanting as to the temperature of 
maximum corrosion of sea water, a question of greater intricacy 
and importance with reference to marine boilers, and now in 
course of experiment. 

167. As regards the third question, namely, the relation be- 
tween the degree of saltness of sea water and its corrosive power 
for iron at common temperatures, I find that in sea water, de- 
pri%'ed of combined air, acting on iron in an open vessel, and 
having therefore to originate its corrosion by air drawn from the 
atmosphere, the corrosive power is inversely as the density of 
the solution, or the amount of its saline contents. 

168. And in the case of sea water holding air in combination, 
the corrosive power is compounded of the direct ratio of the 
volume of combined air, and of some function of the amount of 
saline contents. 

169. The tendency of dissolved salts to prevent the absorp- 
tion of air by water, which is such, that a saturated solution of 



2?50 RKPORT — 1840. 

sea salt, deprived of aii', can scarcely be made to absorb air at 
all; and that in dissolving most salts, expel the combined air from 
the water of the solution, united with the circumstance, that the 
voltaic conducting power of the water is greater in proportion to 
the amount of its saline contents, indicate that fresh water may 
hold so much combined air (not to speak of carbonic acid) as to 
act more rapidly on iron than sea water ; that, on the other 
hand, with much less combined air, the superior conducting 
power of the saline solution may place its corrosive power on a 
level with or above that of the former ; and that, bj' the variable 
combination of these two elements, within their respective limits 
of saturation, any assignable ratio may exist of the corrosive 
power of aerated fresh and sea water. 

This might seem to render our enlarged experiments in the 
open sea nugatory ; but it will be recollected, that the compo- 
sition of sea water, both as to solid and gasiform contents, is 
very nearly constant. 

The experiments from which these conclusions* have been 
deduced, were made on equal parallelepipeds of the cast iron, 
as in class No. 1. a. 77? exposed during equal times, and the 
oxides produced washed off, filtered and weighed ; hence they 
were all made in vessels of limited size. 

The part which the combined air plays in these reactions is 
very remarkable ; it seems to belong to the same class of phse- 
nomena as those known both in inorganic and organic chemistry, 
where the presence of a third body is required to commence or 
sustain the reactions of the three, any two of which alone are 
quiescent. Thus gallic acid, lignin and other analogous sub- 
stances, suffer no change, either in air or in water ; but add to 
the water a minute portion of an alkali, or alkaline earth, and the 
process of oxidation commences at once. Alcohol stands in the 
like predicament. 

170. It seems probable that the air, in the case of the reaction 
on iron, is not decomposed directly by the iron at all, but by its 
protoxide, previously formed by decomposition of the water, 
catalytically, or due to the presence of the combined air. If so, 
we should expect to find hydrogen evolved from the first mo- 
ment, as well as nitrogen, produced by the decomposition of 
the air. But water, although combined with air, absorbs about 
one and a half per cent, of hydrogen, while, unless the air be 
previously expelled, it absorbs no nitrogen ; hence decomposition 
proceeds for some time before hydrogen is evolved ; but on stop- 
ping the reaction at an early stage, and expelling the air andi 

* Report, § 158 to 169. 



ON THK ACTION OF AIR AND WATER UPON IRON, 231 

absorbed gas, traces of hydrogen can be detected: at a subsequent 
stage, ai)d especially if the mass and surface of iron be great in 
proportion to the volume of water, hydrogen and nitrogen are 
both evolved, and the white, greenish or black oxides before 
produced, become red. When this has arrived, the presence of 
air is no longer essential to cany on the decomposition of the 
water, the sesquioxide of iron, which acts as an acid to its own 
base, supplying its place. At a still later stage, ammonia is very 
frequently formed, especially where much carbon is disengaged 
from the iron in the state of plumbago. These reactions closely 
analogize with those presented by tin when acted on by nitric 
acid. This metal, when pure, will scarcely, if at all, decompose 
water cold ; yet, when it decomposes nitric acid, it decomposes 
water at the same moment ; hydrogen is given off, and ammonia 
is sometimes produced during the oxidation of the tin ; but this 
rather digresses from the practical intention of the present re- 
port. 

171. The powerful corrosive action of foul sea water (evi- 
denced in Table No. IV.) by water holding putrifying organic 
matter in solution and suspension, is due, in great part, to 
the quantity of hydrosulphuric acid (H + S) disengaged from 
the mud at the bottom, and with which the water is im- 
pregnated. The iron, acted on by the water in presence of 
its combined air and carbonic acid, forms hydrated oxides 
(FeO + HO) and (Fe^ Og + Fe + H O), and carbonate of 
iron (Fe + C O^), and probably, in some cases, basic salts of 
some organic acids. These, continually exposed to streams 
of hydrosulphuric acid, are in part converted into protosul- 
phuret of iron (Fe S), and in part into the bisulphuret of the 
protosulphuret or magnetic pyrites (6 Fe S + Fe Sg), both being 
formed in an amorphous state, or occasionally deposited in mi- 
croscopic crystals in the tissue of decaying organic substances. 
Both of these sulphurets are of most unstable constitution, and 
rapidly oxidize under the action of air and water, forming proto- 
sulphate (Fe O + S O3) + 6 HO, and the disulphate of the sesqui- 
oxide (2 Fe^ O3 + S O3) + 6 H O, and frequently various other more 
basic sulphates. These, when soluble, are washed away, and 
rapidly expose fresh surfaces of the iron to oxidation. In every 
case, the water charged with these salts has become a better 
conductor, and a more powerful agent in maintaining corrosion. 

But organic matter in a state of putrefaction is one of the 
most powerful deoxidizing agents known, — so much so, as to be 
capable even of reducing sulphate of lime in the state of gypsum ; 
hence these sulphates of iron are in their turn reduced in part 



232 KEPORT— 1840. 

back to sulphurets ; and accordingly, in the neighbourhood of 
ii'on exposed in these conditions, organic matters are frequently 
found, lined, penetrated, or coated with crystals of bisulphuret 
of iron (Fe So), or common pyrites, while their oxygen has gone 
to form carbonic acid and hydrosulphuric acid, both in their turn 
again to react in presence of air and water upon the iron. 

Hence, then, the prodigious power of degradation of castings 
or forgings of iron, when exposed to the foul water of the sewer- 
age of great cities, as so often observed ; hence the cause of the 
destructive action of " bilge-water " upon the holding down 
bolts of marine engines. 

172. A very interesting case, verifying the occurrence of these 
phaenomena, has recently been observed and examined by the ac- 
curate Berthier*. " On the 15th June, 1837, an ancient malle- 
able iron anchor was taken up from the bottom of the river 
Seine, nearly opposite Gros Cailloux. It was found imbedded in 
a conglomerate of pebbles, bones and altered wood, with grains 
of sand and fragments of pottery, of a light gray colour, and 
held together by a calcareous cement, which had accreted round 
the metal. The anchor was two metres long, and weighed not 
less than 200 kilograms. It was thought to be of the fifteenth 
century ; its form, however, agrees with those of the sixteenth; 
and it cannot be more ancient than a.d. 1400. The crust 
was easily detached by a blow. At one end was found a piece 
of wood in immediate contact with the iron ; this had pre- 
served its ligneous texture, so as to be easily recognisable ; but 
it was deeply altered in its qualities. Its aspect was that of a 
dark gray homogeneous mass, with an uneven fracture, and it 
was strongly magnetic. By calcination and roasting, it lost 
0*375 of its weight, and exhaled a strong odour of sulphurous 
acid. Acetic acid dissolved from it 0*65 of pure carbonate of 
lime, while hydrochloric acid dissolved it nearly entirely with 
disengagement of hydrosulphuric acid. 

" The residue was composed of portions of unaltered wood, 
mixed with a small quantity of persulphuret of iron (bisul- 
phuret). 

" The analysis of the whole gave 

Carbonate lime 0"65 

reS = protosulphuret iron .... 0*18 
Fe 82= persulphuret iron .... 0*07 
Ligneous matter 0*10 

1*00 

* Annales des Mines, vol. xiii. p. 661. 



ON THE ACTION OF AIR AND WATER UPON IRON. 233 

The iron must be, for the greater part, in the state of mag- 
netic pyrites (6 Fe S + Fe Sg), and the remainder in the state of 
persulphuret. The gray paste of the crust is coloured like- 
wise by the sulphuret of iron [Berthier does not say which]. 

"The production of sulphuret of iron at the surface of this 
anchor in the Seine in contact with wood, is not surprising, 
since we know that its waters contain sulphate of lime, and 
that sulphates in solution are converted slowly into sulphurets 
in presence of organic matter, with production of carbonate of 
lime. 

" The carbonic acid, dissolved in the water, must have had 
likewise some influence on the results of this reduction, and 
it is probably to its presence that we may attribute the forma- 
tion of the persulphuret of iron." 

These facts sufficiently indicate the accordance to nature of 
the theory of reaction of putrid waters which has been advanced, 
and are fertile in conclusions of practical importance to the en- 
gineer occupied in works of construction in iron, connected with 
the docks or harbours of large towns, or in similar situations. 

173. The average minimum corrosion is indicated (by Tables 
V. and VI.) as occurring in clear river water, containing air in 
combination. This difference below the index of corrosion for 
clear sea water is to be accounted for upon the general princi- 
ples already laid down * ; and as subsidiary causes influencing 
the results are to be noticed, the absence of all extraneous cor- 
rosive agents, and the circumstance that the coat of oxide of 
iron formed in fresh water adheres obstinately to the iron, often 
forming imperfect crystals, of brown hematite (/er oligiste), 
and is not removed in a loose pulverulent form with the same 
ease as it is in sea water, and hence acts in some degree as a 
cloak, or partially impervious covering, to defend portions of 
the metal from further action. 

174. It will be further observed, from Tables III. and VI., 
that wrought iron suffers greater loss by corrosion in hot sea 
water (temp. 115° Fahr.) than under any other circumstances — 
an important result as respects the construction of marine en- 
gines and boilers. Upon the latter point a special set of ex- 
periments are in progress, having in view principally the points 
of inquiry suggested f ; and should the results of these experi- 
ments give a decidedly advantageous point of concentration at 
which to work marine boilers (other circumstances being consi- 
dered), there will be no difficulty, by the aid of the brine-pumps 
now occasionally used in first class steamers, and of Mr. Sea- 

* §§ 1G7, 1C8, 169. t First- Report, § 78. 



234 REPORT — 1840. 

ward's salt gauge, in preserving any such saline condition in the 
water within the boilers as may be desirable. 

175. These Tables also show that in general the removal of 
the exterior "skin" of a casting by planing or filing, to the depth 
of one fourth of an inch or more, great!)' increases the corrosive 
action of air and water upon it, so that the cast irons so cir- 
cumstanced show an average amount of corrosion, or, as I have 
ventured to name it in the Tables, have an index of corrosion 
not much less than that of wrought iron. This shows promi- 
nently the value of a close-grained and dense metallic surface 
for dvirability. 

17(>. We further remark, that while vvrought iron corrodes 
faster than cast iron, with the skin so removed, in clear sea 
water, on the contrary, the cast iron, with its surface or skin 
removed, corrodes faster than wrought iron in clear river water. 
This is due to the circumstance that the coat of hardened oxide 
{fer oligiste*) formed in clear river water, adheres much 
less obstinately to cast than to wrought iron, and hence me- 
chanically protects the former less, while in sea water the coat 
of oxide formed is more or less pulverulent in both cases. 

177- There are two facts of an altogether novel and singular 
character which these Tables present us with for the first time 
— the first, that " chilled " cast iron, of whatever sort, upon the 
whole corrodes faster than the same sort of iron cast in green 
sand ; the second, that the size, or scantling (and perhaps the 
form) of a casting in iron forms one element in the rate of its 
corrosion in water. 

178. With respect to the first, I have remarked f, that 
chilled cast iron is that which, as compared with mottled or 
dark gray cast irons, should corrode with the least rapidity 
on principles considered as established. The facts now for 
the first time elicited by experiment, however, show the di- 
rect contrary to be the case. This may appear at first sight 
to conflict with the principles already laid down ; it does not, 
however, do so in any respect. It is still quite true that chilled 
cast iron (that is to say, cast iron containing a minimum of sus- 
pended or uncombined carbon, and of the highest density) 
will corrode the most slowly, provided it be homogeneous |. 
But practically, the exterior surface of no chilled casting is 
homogeneous ; on the contrary, it is variable to a greater 
degree than that of any other sort of casting, hence the forma- 
tion of those innumerable voltaic couples by whose action cor- 
rosion is promoted : in other words, the results of the present 
• § 173. t See §§ 3f), 44, 49. + § 55. 



ON THE ACTION OF Alll AND WATKR UPON IRON. 235 

experiments show that the voltaic action produced at the sur- 
face of chilled cast iron, by its want of homogeneity, increases 
the corrosion of the metal by menstrua, to agrf«/er extent than 
its great density and hardness, and small amount of uncombined 
carbon, are capable of retarding its corrosion, in comparison 
with other sorts of cast iron. In confirmation of this it will be 
observed, that in almost every case the condition of the corroded 
surface of the " chilled " specimens has been " tubercular," — a 
form of rust which, whenever it is found on iron, is an unfailing 
index of a want of uniformity of substance. This want of ho- 
mogeneity, however, is less in every chilled casting as we recede 
from its surface towards the interior ; and, accordingly, I ex- 
pect that the result of the next two years' corrosion of those 
specimens, the whole of which are now immersed, and proposed 
to remain so for that period, will show rather a diminished excess 
in the index of corrosion of "chilled" over the other sorts of 
cast iron ; the difference also diminishes with increase in bulk 
of a chilled casting, which must be more uniform the larger 
it is. 

179. This leads to the second fact brought to light by these 
results, viz. that the size (and perhaps the form) of castings in 
iron influences their rate of corrosion. With the view to deter- 
mine whether any difference in this respect might exist, it will 
be seen that in the series a, immersed in clear sea water, nearly 
every sort of cast iron has duplicate specimens experimented 
on ; viz. of one inch in thickness by five inches square, and of 
one quarter of an inch in thickness by five inches square, but 
differing in no other respect whatever save in this one dimension 
only. Yet it will be observed, that throughout the amount of 
corrosion of the quarter of an inch, or thiimer pieces, is greatly 
more than that of the thicker, or one-inch pieces of each sort 
of iron. 

The difference is greatest in the softest and most carbonace- 
ous, or leather "graphitic" cast irons, and least in the hard, 
dense, silvery cast irons. Thus in the Vartey Hill (No. 2) hot 
blast iron, the index of corrosion of the quarter-inch casting to 
that of the one-inch, is about 5'5 : 1 ; in the Cinderford (No. 1) 
cold blasts as 10"35; in the Muirkirk (No. 2) cold blast as 
11*5 : 3, while in the Calder (No. 4) hot blast it is only as 
6' 76 : 6*20, or nearly in ratio of equality. 

This very striking circumstance would scarcely have been 
predicted before the present results forced it on our notice ; 
yet its rationale is easy vipon principles just applied to the case 
of " chilled " castings. These thinner castings have cooled 
much faster, and more irregularly than the thicker, or one-inch 



236 REPORT — 1840. 

ones ; hence are much less homogeneous, and contain dispersed 
veins and patches liarder than the rest of their substance ; hence 
again the formation of voltaic couples, and accelerated corro- 
sion of surface. 

180. This novel fact leads us to some important practical 
deductions. We at once see the advantage in durability that 
weight for weight castings of massive scantling have over those 
of attenuated ribs and "feathers." We see the importance of 
casting the "feathers" on ribbed castings intended to be sub- 
merged, of equal scantling with the other parts to which they 
are attached, otherwise the attenuated rib will be eaten away 
long before the principal parts of the casting will have suffered 
much ; and this not merely because there is less stuff m the rib 
to he eaten away, but because its smaller size gave cause for 
its being eaten away proportionally faster, and in preference 
to the grosser rib. 

181. We see the importance of having all ribbed castings 
cooled in the sand before being stripped from the moulds, so as 
to ensure the greatest possible uniformity of texture if intended 
to be submerged. Indeed, this precaution ought to form part 
of the engineer's specification for guidance of the founder in 
preparing castings for every aquatic work, and for other reasons 
it might be added for every work. 

182. These views give the rationale of the fact which has been 
often noticed, but never explained, that the back ribs, of cast iron 
sheet piling, decay much faster than the faces of the piles, al- 
though the latter are more exposed. Thus in the Blackwall 
piling the front ribs of the main piles are two and a half inches 
thick, while the " feather" or back ribs are but one and a quar- 
ter of an inch ; in the sheet piles the front ribs are one and a half 
or one and a quarter inch, and the feathers but one inch. 

183. The principles we have now got also indicate that cast- 
ings in " dry sand and loam," will probably be, cceteris paribus, 
more durable under water than those cast in " green sand." 

184. In general, the results of these experiments show that 
the cast irons with low commercial marks, the numbers 3 and 4, 
&c., corrode locally and generally become pitted ; while the 
high marks, the numbers 1 and 2, &c., corrode with considerable 
uniformity over their whole exposed surface, in accordance with 
the general principle just stated. 

185. On the whole, the practical preference appears so far to 
be due to the Welsh cast iron for aquatic purposes ; a fortunate 
circumstance, seeing from thence we draw the largest supplies 
of iron. Closeness of grain is especially desirable, and what- 
ever can be done in way of mixtui'e of different makes of iron 



ON THE ACTION OF AIR AND WATER UPON IRON. 237 

to increase this property will be valuable. Still more definite 
results, however, are to be expected from the examination of 
the suite of specimens again after their present immersion. 

186. With respect to cast irons made by the hot and cold 
blasts, the index of corrosion appears to be, on the whole, 
slightly in favour of the cold blast, but not much ; a circum- 
stance possibly attributable to the hot blast iron containing a 
different proportion of alloyed metals of the earths and of sili- 
con, as Dr. Thompson has shown*, and to their general differ- 
ence in density, as hereafter to be noticed. 

187. The great elements of difference in corrosion, however, 
as respects the iron itself, appear to be, — I. The degree of ho- 
mogeneity of substance of the metal, and especially of its sur- 
face. II. The degree of density of the metal, and state of its 
crystalline arrangement. III. The amount of uncombined 
carbon or suspended graphite contained in the iron. The 
more homogeneous, the denser, harder and closer-grained, and 
the less graphitic, the smaller is the index of corrosion of any 
given specimen of cast iron, 

188. The Table No. VIII. is one deduced from all the pre- 
ceding, in which, assuming the rate of corrosion found by ex- 
periment for a period of 387 days, to continue uniform, the ave- 
rage loss per superficial foot of surface, for each general class 
of iron, and thence the depth to which any casting will be cor- 
roded in a period of one century is shown. This may be con- 
sidered as a specimen table, showing one practical end pro- 
posed by these results. 

189. The assumption here made, that the rate of corrosion 
will continue for a century uniformly as during the first year, 
is possibly not critically correct ; the error, if any, however, is 
one not in excess, but in defect, for though the rate of corrosion 
may accelerate, it certainly is not likely to be retarded. This point 
the results of the continued experiments on the same specimen 
novv in progress will, after two years more, fully determine. 
Meanwhile I have strong reason to conclude that, after a suf- 
ficient period has elapsed to enable submerged cast iron to be- 
come coated with a spongy covering of plumbago produced by 
its own destruction, then the further rate of corrosion will be 
somewhat accelerated, and that hence the results contained in 
this table are rather below the truth. 

190. These deductions, in general, indicate that from three 
to four tenths of an inch in depth of cast iron, one inch thick, and 
about six tenths of an inch in depth of wrought iron will be 
destroyed in a century in clear sea water, a conclusion probably 

* Report of the British Association, vol. vi. 



238 REPORT — 1840. 

not very far astray where no special perturbations or causes of 
corrosion supervene. 

191. This gives a period of duration of about two hundred 
years to the cast iron wharf wall, lately constructed at Black- 
wall, London, before the castings shall have become so atte- 
nuated and fragile as to be useless. 

192. Having been recently in correspondence with Col. Pas- 
ley, Royal Engineers, and Lieut. Symonds, of the same corps, 
regarding the state of the iron taken up from the wreck of the 
Royal George, with specimens of which I have been favoured by 
the former gentlemen, an opportunity has occurred, through in- 
formation for which I am indebted to Lieut. Symonds, of controll- 
ing or testing the accuracy of these results in a very decisive 
way. A number of guns have been taken up from the wreck of 
the Edgar, which were upwards of one hundred and twenty-nine 
years under water. The depth to which they were corroded 
from their original dimensions, which were known, was found 
to be seven-eighths of an inch on the average. Now let us ap- 
ply the results of our experiments to see what depth of cor- 
rosion they predict under the circumstances. Turning to Table 
No. VL, we find the average loss for hard gray iron with the 
skin removed (as in a bored gun) per square inch of surface in 
387 days = 13*55 grains in foul sea water = 195 1*2 grains per 
square foot, which, multiplied by 123*4, the times 387 days is 
contained in 130 years, and divided by 7000 = the grains in a 
pound avoirdupois, give a loss by cori'osion of 34*4 lb. per square 
foot; but the actual loss has been 32*81 lbs. per square foot, 
that being the weight of a square foot of cast iron seven eighths 
of an inch thick. This strikingly close result is corroborated 
by others on iron from the Royal George, immersed for fifty- 
eight years, corroded from half an inch to three fourths of an 
inch in depth on the average, and together prove that the re- 
sults of these experiments may be relied on practically. 

193. I have now to make a few remarks upon the supple- 
mentary tables which accompany the five first tables of experi- 
ments, viz. those containing the results of corrosion of cast iron 
covered with various paints and varnishes. These were mobtly 
such as ai-e generally in use for such purposes, and were laid on 
with great care, so as to cover the whole surface completely, and 
leave as few microscopic pores as possible in the covering. The 
general results are these : of the ten sorts of paints or varnishes 
tried, there is not one that will completely prevent corrosion, 
nor one that will remain perfectly adherent or undecom- 
posed for a single year under water. In foul water, fresh or 



ON THB ACTION OF AIR AND WATJill UPON IRON. 239 

salt, white-lead paint perishes at once, the white-lead being 
probably converted into sulphuret by the action of the nascent 
hydro- sulphuric acid ; yet white lead forms the great staple 
base for all the paints generally used for exposed iron works. 
Caoutchouc varnish appears to be the best covering in hot water, 
and generally in all the others asphaltum varnish. But boiled 
coal tar laid on, the iron being hot, has decided advantages over 
every other, the reasons of which v>'e shall presently see. It is 
sufficiently obvious, howevei*, that nothing very important in 
the way of protection is to be hoped for from any one of the 
coverings tried, at least when used alone. 

194. Since these experiments were commenced, my atten- 
tion has been drawn to the results of an analogous series obtained 
by Mr. James Princep of Calcutta, and contained in the Journal 
of the Asiatic Society of Bengal, which appear worthj' of notice. 
The proposed extensive employment of iron steam-boats on the 
Ganges, and the rapid corrosion to which iron is subject in a 
hot climate, induced the local government to cause these expe- 
riments to be made, to endeavour to procure a varnish that 
should preserve the surface of the metal. Mr. Prinsep took two 
sets of six wrought iron plates, each 3 feet by 2 feet, upon which 
various paints and varnishes were applied. One set was just 
completely submerged, and the other half-immersed, one half of 
each plate being in the air and the other half in the water of the 
canal at Calcutta, near the Chitpur lock-gates, where it is only 
slightly salt. After three months' exposure the two sets were 
taken up and examined, and the following table contains the re- 
sults, which it is to be regretted have not the numerical pre- 
cision that would have been obtained by weighing the plates 
before and after immersion. 



Experiments 



240 



REPORT — 1840. 



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ON THE ACTION OF AIR AND WATER UPON IRON. 241 

Coal-tar thus appears to stand preeminent as a covering varnish 
for iron. The general accordance of these experiments with 
those of the present report is satisfactorj\ The anomalous re- 
sult, No. IX., with the zinc protector, Mr. Prinsep considers due 
to its containing lead, which was proved to exist in it. Coal- 
tar was finally adopted for the iron vessels navigating the wa- 
ters of the Ganges. 

195. In the progress of these researches I procured, by the 
favour of Henry English, Esq., of the Mining Journal, a speci- 
men of " zinc-paint" now sold as a covering for iron when 
ground in oil ; that which I received is in the form of a mode- 
rately dark, gray powder, which decomposes water rapidly ; suf- 
ficiently fine to form a strong full-bodied paint, when ground 
with oil, which dries rapidly, though not quite free from gritti- 
ness. As I could not obtain any very definite information as to 
the origin or mode of preparation of this substance, and its va- 
luable qualities were highly spoken of, I considered it worth 
making a quantitative analysis of. It will be unnecessary here 
to state the method pursued ; the analysis was performed with 
care, and the results give the follovving composition as that of 
the zinc-paint : 

Sulphuret lead 9-05 

Sub-oxide and oxide of zinc . . 4-15 

Metallic zinc 81*71 

Sesquioxide iron .... 0* 14 

Silica I'Sl 

Carbon 1.20 

Loss 1-94 



100 
It would hence appear to be probably some residual matter 
obtained in the zinc-works. I have at present specimens of it 
upon iron in all the six conditions of experiment, and hope at a 
future period to be able to report favourably of the results. I 
should, ci priori, conceive that it would make an excellent body 
for a sound durable paint, well suited to works in iron. 

196. Another sort of paint has been for some time much 
recommended by the vendors, made from impure black oxide 
manganese ground in oil. This may possibly form a powerful 

drier, but, from its harsh and dense substance, can never be 
a suitable " body" for a paint j nor does it seem to offer any 
special advantage in the former respect. 

197. The defects of ordinary oil-paints seem chiefly to arise 
irom the instability of constitution of the fat oils, turpentine 
or other organic substances entering into their composition. 

1840. i> '' 



242 REPORT— 1840. 

All the fixed oils may, in fact, be viewed as organic salts or com- 
binations of the oily acids, with a compound base generally 
" glycerine" (Cjj H^ O^,), or vegetable mucilage. Most of the 
oil of turpentine found in commerce also contains more or less 
pinic and silvic acids*. Now all these acids i-eadily quit their 
weakly positive organic bases, to form salts with the more 
powerfully basic oxides of the metals, with which they are 
used commonly in the formation of paints, as white lead, 
ochres, &c. &c. ; in this combination, however, the original 
organic bases are left free to form new combinations, under the 
joint action of air and moisture, and of the metal on M'hich 
they may be spread. The resultant action of all which is, that 
the paint, in workmen's language, gets ' killed' ; that is, be- 
comes either more or less soluble in water, or pulverulent and 
removable by it ; and in place of preserving an oxidable metal, 
promotes its corrosion. Pinic and silvic acids act powerfully 
as such, upon mauy bases ; the former decomposes the car- 
bonate, acetate, and most of the organic acid salts of copper, 
several of the earthy acetates, and the alkaline carbonates with 
effervescence when fused with them. Yet it is remarkable, 
that upon the peroxide of copper, and several other peroxides, 
it has scarcely any action. The electro-negative relations of 
commercial turpentine, then, may be neutralized, if desirable, 
in composing a paint ; but this is in every case attended with a 
diminution of its power to resist the action of water. Priestley 
first ascertained that volatile oils, such as turpentine, absorb 
oxygen or atmospheric air, and combine with them in part. 
In this they closely resemble the fat oils, and the result is 
analogous in both ; they finish by conversion into resins. 
Hatchett's experiments, and also the saponification by potass 
of oil of turpentine, indicate that the volatile oils do not unite 
directly with metallic oxides, but receive oxygen from then^, 
become acid resins, and thus form resinous salts. Thus, if oil 
of turpentine be heated with peroxide of lead, water is given 
off. The oil becomes dark brown, viscid, and at length solid ; 
the result is a compound of resin and oxide of lead ; common 
resin, as Blanchet and Sellf have shown, is oil of turpentine, 
with an atom of oxygen combined = C,o Hg O. Hence we 
may conclude that oil of turpentine plays no chemical part in 
the constitution of paints, but in so far as it has suffered these 
changes ; in doing so its density is increased and its volume 
consequently diminished, and hence every oil-paint is full of 
microscopic pores, however carefully laid on, as may be proved 

* Unverdorben, PoggendovfF's AnnaJen, vii. to xxi. 
t PoggendorfF's Anna/en, xxix. 133. 



ON THK ACTION OF AIR AND WATKR UPON IRON. 243 

by the microscope ; and thus, when laid on an oxidable metal, 
corrosion slowly takes place through these, or, as workmen 
say, " it rusts under the paint." 

198. In the absorption of oxygen, which takes place when 
an oil capable of being rendered drying, such as linseed or nut 
oil, is exposed to the action of the atmosphere or of oxygen 
gas, the volume of carbonic acid formed is by no means equi- 
valent to that of the oxj'gen absorbed. Hence it is obvious 
tliat the drying of oilj^ paints is effected by a slow but real 
combustion of part of the hydrogen of the oil forming water, 
and by the partial acidification of the vegetable mucilage. This 
process is greatly accelei-ated by the presence of various sub- 
stances, but particularly carbon in a solid state. It is well 
known that lamp-black and oils mixed together in proper pro- 
portions absorb oxygen so fast as to produce spontaneous com- 
bustion at high temperatures, yet it is the slow combustion of 
the h5'drogen of the oil rendered more active by presence of 
the carbon, to which the exaltation of temperature sufficient 
to produce ignition was at first due. This combustion is already 
in part performed in the oils rendered drying by litharge, &c., 
and still more in the burnt oil used for the ink of copper-plate 
and letter-press printers, and called by them " the varnish." 
In fine, in every combustible compound of carbon and hydro- 
gen, combustion, whether slow or defectively supplied with 
oxygen, seizes on the hydrogen first, and lastly on the car- 
bon, and this leads, in the case of oil paints, to a succession 
of changes of constitution, by which at length the original 
solid material of the paint alone remains in feeble combination 
with a little decomposing resin. 

199. The direction, then, in which we are able to look for 
improvement in the preservative power and durability of our 
paints, is in choosing from amongst the known groups of 
organic substances, those which have greater stability than 
the fat or fixed oils, and which, in place of being acid or 
haloid, are basic or neutral. AmoiJgst the many substances of 
this class which occur, few seem better fitted to form a sub- 
stitute for the fat oils in paints than the heavy oily matter 
obtained by the distillation of resin, to which M. Fremy gave 
the name of 'resinein*'j it has the composition (C^q Hjg O). 
Now two atoms of resin = 2 (Cj^ Hg O) ; hence this oil is 
a fluid resin deprived of an atom of water = (H O). It is a 
heavy transparent oil, destitute of taste or smell, insoluble in 
water and alcohol, not acted on hy caustic alkalies, has a high 
boiling-point = 480° Fahr., and reduces litharge, when boiled 
* Annates du Pharm. xv. 282. 



241 RKPORT 1840. 

with it, as the drying oils do. This substance can be obtained 
in any quantity cheaply ; all the resins possess the property of 
gradually combining w'ith water when long immersed in it, and 
forming a porous compound, analogous in all respects to the 
substance thrown down by water from a solution of resin in 
alcohol, or from its combination with an alkaline solution. 
When the latter is precipitated by an acid a true hydrate is 
formed, consisting of an atom of resin and eight atoms of 
water. Even copal, after having dried as a varnish, is gradually 
acted on in this way l)y water, and becomes pulverulent. Re- 
sinein, however, does not seem to be capable of forming a 
hydrate, and therefore offers decided advantages as an aquatic 

200. Reichenbach has lately shown* that Eupion (Lgi H,o) 
may be obtained by distillation of rapeseed oil. Naphthaline 
and Paraffine are both soluble in the latter ; and these, from 
their stability of constitution and other properties, only require 
a suitable solvent to form the most valuable bases for paint. 
Naphthaline can be obtained in large quantity, in fact it is a 
drug with those who distil naphtha from coal-tar ; and Laurent 
has* hownt that Paraffine may be obtained in abundance by 
distillation from the shale of the coal formations. In the com- 
bination of these with soUd materials, the principal object to 
be held in view to obtain a durable paint is to choose a metallic 
powder or peroxide least liable to be acted on by the agents 
most obnoxious to paints, viz. air, water, carbonic acid, and 
hydrosulpluiric acid, and at the same time capable of intimate 
combination with the organic base. 

201. But in a paint, or rather varnish of Naphthaline or Paraf- 
fine, no solid inorganic substance is necessarily included. The 
only other component needed is a suitable vehicle to cause these 
substances to spread and hold them upon the metallic surface. 
This obtained, a varnish covering, more durable than aiy known, 
Avould probably be produced. This is rendered almost certam 
by the facts already adduced by Mr. Prinsep's and my own ex- 
periments. In these, coal-tar laid on the iroii hot is immea- 
surably superior to every other covering. Now coal-tar in this 
state consists of naphthaline enveloped in asphaltum ; when coal- 
tar is exposed to this temperature, naphtha and other volatile 
matters are driven off, and the results of an imperfect destructive 
distillation, in which hydrogen is lost, while naphthahne is a 
product, remain on the iron a bright and solid varnish, ihis 
not only gives the key to the only true method of applying 
bituminous matter as a varnish, but it indicates the cause ot the 

* Jour, fur Pract. Chim. i. 377. t Annales de C/ihnie, h: 218. 



ON THK ACTION OF AIR AND WATER UPON IRON. 245 

entire difterence in preservative power observed between coal- 
tar so used and Swedish tar laid on cold ; had the latter been 
heated also until decomposition commenced and naphthaline was 
formed, less difference probably would have been found between 
them. 

202. In connexion with this may properly be mentioned the 
method stated to be used for giving the beautiful jet black var- 
nish coating to the Silesian or Berlin castings in iron. These 
beautiful specimens of art are covered externally with an ex- 
cessively thin coat of a black, shining, and remarkably hard 
varnish, which is not acted on for a considerable time by strong 
sulphuric or nitric acid, or for some hours by caustic potass, 
and which resists oxidation of the metal beneath for a long 
time ; but, when continually exposed to air and water, at length 
forms isolated patches of rust, which gradually spread. The 
varnish is said to be thus produced : — the article of iron is sus- 
pended from a wire and covered with a very thin coat of linseed 
oil, it is then hung over a smoky wood fire within about a foot 
of the faggots, and exposed for some time to the smoke and 
flame — generally about thirty minutes ; it is then to be lowered 
to within three or four inches of the fire, now become clear, 
and heated more strongly for a few minutes, and immediately 
immersed in oil of turpentine, from which it is removed to be 
polished with woollen cloths. A second application is some- 
times requisite to give sufficient blackness and brilliancy, which 
is always more readily obtained witn cast than with wrought 
iron. It is difficult to discern the precise nature of the changes 
which the oil undergoes in the process : watery vapour, Eupion 
and carburetted hydrogen are probably given off, and some of 
the volatile products of the wood, in imperfect combustion, 
may enter into combination. A different composition is recom- 
mended in the Dictionnaire Technologique, vol. xxii. p. 164, 
for producing this black varnish, viz. — 

Bitumen of India 0*5 

Resin 0"5 

Drying oil I'O 

Copal or Amber varnish I'O 

with enough of oil of turpentine to make it spread, laid on the 
iron hot and baked. 

203. Amongst the mechanical coverings of iron for prevent- 
ing oxidation, may here be properly noticed the fusible enamel 
patented by Mariott, of London, and since by others. These 
are very fusible glasses, having, by the addition of large quan- 
tities of oxides, about the same expansion as the cast-iron culi- 
nary vessels, to which they were chiefly proposed being applied.. 



24fi REPORT 1S40. 

They iire of very limited application, and appear to present a 
good deal of technical difficulty. 

204. These somewhat scattered facts, in the chemical history 
of paints and preservative varnishes, are little more than suffi- 
cient to show us the barrenness of this region of art, which has 
received no cultivation as yet but that of continued tentation on 
the part of the workman, undirected by scientific principles. 
Much might be hoped for, important in technical results, by the 
enlargement and correction of our still defective knowledge of 
the organic chemistry of the fixed and volatile oils, the resins 
and the bitumens. To paints or varnishes alone, however, we 
are not to look for the means of complete protection from cor- 
rosion for oxidable metals ; their liability to removal by slight 
external forces precludes this ; their proper place, as mechani- 
cal protectors, will be found subsidiary to those which are de- 
pendent on chemical or electrical relations ; and one of their 
most important uses will probably be found in their application, 
in union with substances poisonous to animal and vegetable life, 
to the bottoms of iron ships, to prevent the " fouling" produced 
by their accumulation, and now found of so much incon- 
venience. 

205, At the period of publication of the previous report, the 
preservation of cast and wrought iron, by the electro-chemical 
action of zinc, was beginning to excite that attention which 
was first drawn to it by the views of Sir Humphry Davy, and 
the subsequent experiments of Prof. E. Davy ; but there had 
not been time to enable any very decided results to be given in 
that report. I am now, however, in a condition to state the 
results of a tolei'ably complete train of experiments made on 
the protective powers of zinc, to iron and steel under various 
circumstances, some of which have been continued for upwards 
of two years. 

The experiments I have made on the electro-chemical power 
of protection of zinc to iron are divided into two gi-eat classes — 
those in fresh water and those in sea water ; and each of these 
classes again divides itself into two, namely, those made with 
the preserved and preserving metals submerged to a greater or 
less depth in the fluid, and those in which the metals were ex- 
posed freely to air, and covered by an indefinitely thiti film of 
water constantly renewed, or, in technical language, to " wet 
and dry. In each of these conditions experiments have been 
made on the protected metal, in presence of zinc in a massive 
form in simple contact, through the intervention of the solvent 
or fluid in which both were immersed, and also when the pro- 
tected metal has had voltaic contact established with the zinc by 



ON THE ACTJON OF AIK AND VVATKil UPON IRON. 



217 



actual union, or, as I shall call it, in metallic contact, as in tlie 
case of zinked iron, or iron coated with zinc at its fusing 
temperature. Hence there have been made eight distinct trains 
of experiment on this one branch of the subject, each of which 
lias been carried on upon cast iron, upon wrouglit iron, and 
upon steel, as the following scheme will serve to indicate : 



All freely exposed to air and carbonic acid. 






r Submerged 12 inches < j 

rin simple contact. A [In 

Cast iron [ Submersion indefinitely smalH , 

and < - 

zinc. r Submersion 12 inches . 

(_ In metallic contact. \ r t 

(_ Submersion indefinitely small < ^ 

{Submersion 12 inches . 
Submersion indefinitely small \ J^ 

I /"Submersion 12 inches J _" 

(_ In metallic contact. < ^ ^ 

[ Submersion indefinitely small J ," 

{Submersion 12 inches i, ■, 
Submersion indefinitely small .^ y 

f Submersion 12 inches X ■, 

\In 



iron andW 
zinc. 



and 
zinc. 



In metallic contact. 



|_ Submersion indefinitely small \ ■, 



sea water, 
fresh water, 
sea water, 
fresh water, 
sea water, 
fresh water, 
sea water, 
fresh water, 
sea water, 
fresh water, 
sea water, 
fresh water, 
sea water, 
fresh water, 
sea water, 
fresh water, 
sea water, 
fresh water, 
sea water, 
fresh water, 
sea water, 
fresh water, 
sea water, 
fresh water. 



I will not venture to enter here upon the lengthened detail of 
these experiments, which will probably appear in a more suitable 
place, but merely state the method and principal results ar- 
rived at. 

206. The fresh water used in all these experiments was that 
which supplies the city of Dublin at the north side ; it comes 
from Lough Ouwell, in a limestone district, county Westmeath ; 
it contains no solid matter when filtered, but a trace of car- 
bonate of lime and of carbonate of iron. Tt holds in combina- 
tion, however, one volume in eight of gases evolved on boiling, 
which consist of 

Atmospheric air 94*1 

Carbonic acid 5*9 



100*0 cubic inches. 
The sea water used was invariably that from Kingstown Har- 
bour, of which the analysis has been already given. 



248 RKPORT — 1840. 

All the experiments were carried on with water and air at 
about 62° Fahr. The cast iron is that of a 77, (Table No. I.), 
or hard gray, mixed, Welsh and Scotch iron. 

The wrought iron. No. 2, Welsh bar, and the steel (l) cast 

steel, of the Mersey Steel Company's make. The depth of im- 
mersion in all the submerged experiments was uniformly twelve 
inches, in glass vessels. The zinc used was nearly pure. The 
volume of water employed in each experiment was fifty cubic 
inches. 

Of Cast Iron in simple contact luith Zinc immersed in Fresh 

Water. 

207- If cast iron be perfectly free from any initial stains of 
rust, and quite homogeneous in texture, it is electro-chemically 
preserved by the contact of an equal surface of pure zinc, for an 
indefinite period, during which the zinc is oxidated, the oxide of 
zinc is transferred to the surface of the iron, and forms mammillary 
concretions on it ; after which the protective power of the zinc 
is greatly diminished, and at this stage the contact of any sub- 
stance, even a neutral one, — such as glass with the iron, — is 
sufficient to originate oxidation upon it, which, once established, 
gradually extends, without the zinc having power to arrest it. 
The oxide of iron produced has the composition (Fe O + Fe^ O3) 
+ H0*. 

208. If cast iron, having a polished surface, be suffered to 
contract any coating of rust, although the surface be afterwards 
perfectly polished to the eye, yet zinc, in simple contact, has 
lost nearly the whole of its power of protection ; the zinc and 
iron both oxidize from the moment of immersion. If the surface 
be removed by the file to some depth, however, the remaining 
metal is preserved. 

209. If wrought iron has been exposed to solvent action in 
contact with a powerfully electro-negative metal, as copper or 
mercury, for a considerable time, and its surface be then removed, 
even to the depth of j^th of an inch, or more, with the file, and 
immersed in contact with zinc, the latter is found to have lost 
nearly all protective power with respect to it. Cast iron so cir- 
cumstanced corrodes from the first moment, and the oxide is de- 
posited in tubercles. 

210. On the other hand, if wrought iron, a portion of whose 

* The fovniulEe used for these oxides have respect merely to composition, and 
not to proportion, which varies with tlie duration of exposure. 



ON THE ACTION OF AIR AND WATER UPON IRON. 249 

surface has been in metallic contact with zinc, or other more 
IJowerfuUy electro-positive metal, while immersed in a solvent, 
have its surface removed by the file to the depth of y^^th of an 
inch or more, and be then immersed alone in fresh or sea water 
oxidation does not take place at all for a considerable time, and 
only forms at length in minute detached tubercles. 

211. Thus it appears that wrought iron, which has been for a 
length of time in contact with an electro- negative metal in pre- 
sence of a solvent, acquires an electro-positive polarity, while that 
which has been so circumstanced with an electro-positive metal 
acquires an electro-negative polarity. The same phaenomena do 
not present themselves with cast iron to the same extent, but yet 
are discernible. 

To this curious subject of electro-polarization. Dr. Andrews's 
experiments on bismuth andplatina supply analogous instances ; 
and an interesting paper on the same, as effecting copper and 
platina, has been much overlooked in the thirteenth volume of 
the Journal of the Royal Institution, p. 200. I introduce these 
two last experiments (209. 210) here for the purpose of remark- 
ing, that no piece of iron which has before been used for any such 
experiments as the present, should be used again for a different 
one. Before becoming aware of this, I was tormented with 
anomalous results. 

212. I stated in my previous report, that the views of Payen 
and Dumas, viz. that the cause of tubercular corrosion was a 
slightly alkaline reaction of the corroding water, seemed to me 
unnecessary to account for the phaenomena. I am now enabled 
to state, that the sole essential circumstance to tubercular corro- 
sion is want of homogeneity in the metal corroded, and that I 
have obtained the most marked tubercular corrosion of cast iron 
in pure distilled water, and in acidulous fluids. The corroding 
agent must, of course, be such as will not dissolve the oxide pro- 
duced ; and it must be admitted, that all other things being the 
same, the presence of an alkali greatly exalts the tendency to 
tubercular deposition of oxide, which may, however, take place 
without it. 

Of Cast Iron in si?nple contact with Zinc imynersed in Sea 
Water. 

213. Cast iron, perfectly free from initial rust, is perfectly 
preserved from oxidation in sea water by an equal surface of 
zinc. The latter is oxidated; but the oxide formed is not 
transferred to the surface of the iron, nor does it adhere to 
that of the zinc : it is washed away in a flocculent form, and 
IS partly dissolved by the saline contents of the sea water. 



250 UE PORT— 1840. 

Yet, after the lapse of a considerable time, the whole surface 
of the zinc becomes covered with a thin, black, hard crust of 
sub-oxide, on which are deposited minute crjstals of calc spar, 
produced by decomposition of the salts of lime in the sea water. 
When this has taken place, the protective powers of the zinc are 
greatly diminished, or nearly destroyed. 

Of Cast Iron in simple contact with Zinc at an indefiniteli/ 
small depth in Fresh Water. 

214. Cast iron, free from initial rust, so exposed in contact 
with an equal surface of zinc, is oxidized from the first moment 
of exposui'e. The zinc is oxidized also, and the oxide forms 
concretions at the point of contact of the metals, and increases 
the oxidation of both metals ; so that of two equal surfaces of 
cast iron, exposed during equal times to an indefinitely small 
depth of fresh water, the one alone, and the other in simple con- 
tact with an equal surface of zinc, the latter will lose the greater 
amount by oxidation. 

215. When cast iron, free from initial rust, is exposed to an 
itide/initeli/ small depth of sea water, in simple contact wilh 
an equal surface of zinc, its oxidation is retarded, but not pre- 
vented, and after a time takes place, as in the last case. 

Of Wrought Iron in simple contact with Zinc immersed in 
Fresh Water. 

216. Wrought iron, free from initial rust, exposed in contact 
with an equal surface of zinc, is preserved from oxidation until 
a large amount of oxide of zinc has concreted at the point of 
junction of the metals, when tlie iron gradually begins to form 
tubercular points of oxide on its upper side. The oxide has the 
composition (Fe O + Feg 03) + !! O. Carbon is deposited in 
microscopic crystals on the zinc. 

217. Wrought iron, under the same circumstances as above, 
but immersed in sea water, is preserved for a time. But although 
the oxide of zinc deposits on the iron with greater difficulty in 
sea than in fresh water, yet it does so at length, along with cry- 
stals of calc spar; after wliich the protection of the zinc becomes 
uncertain, and is disturbed by the contact of any neutral solid. 

Of Wrought Iron exposed in simple contact zcith Zinc at an 
indefinitely small depth in Fresh JVater. 

218. When wrought iron, free from initial rust, is exposed 
thus, in simple contact with an equal surface of zinc, oxidation 
commences at once, and proceeds rapidly. The zinc is oxidized | 
also, and the oxide of zinc adheres to the points of contact of | 



ON THE ACTION OF AIR AND WATER UPON IRON. 251 

the metals in mammillarv concretions. The oxide of iron formed 
has the composition (Fe O + Fe^ O3) + (Fe O 4- C Oo) + H O. 

219. Whemvrought iron is exposed under the same circum- 
stances as above, but to sea tvater, the same phasnomena as in 
the last case present themselves, but much more slowly, much 
of the oxide of zinc being dissolved in the sea water. 

Of Cast Steel exposed in simple contact ivith Zinc, immersed 
in Fresh Water. 

220. When cast steel, free from initial rust, is exposed in 
simple contact with an equal surface of zinc, the general surface 
of the metal remains bright, but tubercular oxidation gradually 
takes place at the points of junction of the steel and zinc ; the 
latter oxidizes less as this proceeds, and finally ceases to protect 
the steel at all. Carbon is transferred from the steel to the 
surface of the zinc. The oxide formed has the composition 
(FeO + F2 03) + HO. 

Of Cast Steel in simple contact with Zinc immersed in Sea 
Water. 

221. In this case, the same phaenomena take place as in the 
last, but much more slowly. 

Of Cast Steel in simple contact ivith Zinc, exposed in an in- 
dejxnitely small depth of Fresh Water. 

222. Cast steel, free from initial rust, thus exposed in sim- 
ple contact with an equal surface of zinc, soon begins to rust in 
irregular patches. The zinc also oxidizes, and the oxide forms 
concretions at the points of contact ; after which the steel ox- 
idizes still faster, so that in equal time it loses rather more by 
oxidation than an equal surface of cast steel, exposed as above, 
alone. 

223. When cast steel, free from initial rust, is exposed in 
simple contact with an equal surface of zinc to an indefinitely 
small depth of sea water, the same pliffinomena, as in the last 
case, present themselves, but much more slowly. 

Of Wrought Iron in metallic contact ivith Ziiic, or Zitiked 
Iron. — Of Zinked Iron immersed in Sea Water. 

224. A plate of zinked iron was immersed for twenty-five 
months in sea water ; its whole surface was zinked. On ex- 
amination, the surface was covered with a hard black coat of 
sub-oxide, over which was a thin coating of crystalline car- 
bonate of lime, but no symptoms of oxide of iron were to be 



252 RKPORT — 1840. 

seen. Very little of the zinc was dissolved, and a little loose 
oxides were in the bottom of the glass jar, which proved to be 
(Zn O + C O2) + (Ca O + C 0„) + (Fe O f Fe^ O3) + (Zn O + FesOg) 
+ HO. 

225. A plate the same as the foregoing in all respects, im- 
mersed the same time in a saturated solution of common salt, 
on examination presented the same phsenomena, but less strongly 
ma rked. 

Of the ratio of Zinked surface to that of Iron necessary to 
protect the latter, immersed in Sea Water. 

226. When equal parallelopipeds of partiallj' zinked iron are 
immersed in sea water, having the following ratio of zinked 
surface to that of the iron, viz. 





Zinc Surface. 


Iron Surface 


a . 


. . 400 . . 




^ . 


. . 2-00 . . 




7 • 


. . 1-00 . . 




S . 


. . 0-25 . . . 




e . 


. . 0-124 . . . 




K . 


. . 0-065 . . 




-n • 


. . 0-03125 . 




6 . 


. . 0-015625 . 




I . 


. . 0-00786 . 


1—1 



the zinc is rapidly oxidized in all, and the amount of oxide of 
zinc formed is in the ratio of the surface of zinc exposed ; 
the other, or e — , elements being all of equal surface. The oxide 
of zinc formed is flocculent, and does not collect either at the 
iron or zinc poles, and is partly dissolved by the sea water. 

The iron remains bright and free from oxide, with every pro- 
portion of zinc, down to the ratio of 0*00786 : : 1 of iron. 
Hence the limit of protective power of zinc in metallic contact 
with iron immersed in sea water is between g^^th and xIf^^ 
of the surface of the latter, at which point oxidation takes place 
rapidly. 

Of Iron in metallic contact luith Zinc immersed in Fresh 
rVater. 

227. When several equal parallelopipeds of iron ai-e immersed 
in fresh water, having the following ratios of zinked surface to 
that of iron, viz. 





Surface of Zinc. 


K . 


. . 4.-00 . . 


\ . 


. . 2-00 . , 


fl . 


. . 1-00 . . 


V . 


. . 0-25 . . 


O 


. . 0-125 . . 


TT . 


. . 0-065 . . 


P • 


. . 0-013125 . 


o- . 


. . 0-0156-25 . 


T . 


. . 0-00786 . 



ON THE ACTION OF AIR AND WATER UPON IRON. 253 

Surface of Iron. 

: ... 1 

: ... 1 

: ... 1 

: ... 1 

: ... 1 

: ... 1 

: ... 1 

: ... 1 

: ... 1 

the zinc in all is corroded, and the amount of oxide formed in 
equal times, is proportionate to the surface of zinc ; the other, 
or e — , elements being equal. The oxide of zinc is deposited on 
the zinc pole in mamniillary concretions. The iron remains bright 
and free from oxide, with every proportion of zinc, down to the 
ratio of 0*103125 of zinc : : 1 of iron; with this and below it, 
tubercular oxidation takes place on the iron surface to an extent 
in equal times proportional to some unascertained function of 
the surface of zinc. 

228. Hence it is proved that at the depth of immersion of all 
these experiments, viz. twelve inches, the limit of protective 
power of zinc in metallic contact with iron in fresh water lies 
between xV^h and j^^d of the surface of iron ; or that it re- 
quires about four times the amount of zinc surface to put in 
motion the same quantity of electricity, and thus to protect 
wrought iron in fresh water by its aid that will effect this result 
in sea water. But after the lapse of a considerable period in fresh 
M'ater, all the other parallelopipeds began to show signs of rust 
or of tarnish in the inverse order of their respective surfaces of 
zinc ; hence time alone seems requisite in fresh water to cause 
the protective power of any amount of surface of zinc for iron 
to cease, which is confirmed by the following fact. 

229. A plate of iron, whose entire surface was covered 
with zinc in metallic contact, was immersed for twenty-five 
months in fresh water. On examination, much flocculent oxide 
of zinc had been formed, and lay in the bottom of the glass 
vessel, which was in some places stained with red oxide of iron. 
The zinc surface was found in irregularly scattered patches, 
wholly removed down to the iron, which was covered with per- 
oxide. Hence about two years appear to be the limit of pre- 
servative power of zinc to iron in fresh water, applied in fusion 
over its wholesurface by the ordinary method. Itis to be noticed, 
that the zinc surface was removed by solution, unequally or in 
patches, indicating local action ah initio; and it has been before 



254 REPORT — 1840. 

shown, that as soon as oxidation takes place at any point upon 
the iron surface, the pi-otective power of the zinc is at once 
diminished, or rendered null. 

Of Iron in metallic contact ivith Zinc exposed to an indefinitehj 
small depth of Sea JVatev. 

230. When seA'eral equal parallelopipeds of iron, having the 
following ratios of zinked surface to those of iron, viz. 

Surface of Zinc. Surface of Iron. 

«... 4-00 ... : ... 1 
h . . . 2-00 ... : ... 1 
c . . . 1-00 ... ; ... 1 

d . . . 0-25 ... : ... 1 
e . . . 0-125 ... : ... 1 
/ . . . 0-065 ... : ... 1 
g . . . 0-13125 . . : ... 1 
h . . . 0-015625 . : ... 1 
i . . . 0-00786 . . : ... 1 
are exposed to an indefinitely small depth of sea water, the iron 
I'emained bright and free from oxide, down to the ratio of 0-065 
of zinc to 1 of iron ; but in all below this the iron suffered ox- 
idation tubercularly. The oxide of zinc for-aied did not adhere 
to either the iron or the zinc, and was partly precipitated in a 
flocculent form, and partly dissolved in the sea water. Within 
the period of experiment the limit of protective power of zinc 
in metallic contact with iron, under the present condition, lies 
between j^^nd and g'jth of the surface of the latter. 

Of Iron in metallic contact ivith Zinc, exposed to an in- 
definitely small depth of Fresh Water. 

231. When several parallelopipeds of iron having the follow- 
ing ratios of zinked surfaces to those of iron, viz. 

Surface of Zinc. Surface of Iron. 

h 30-0 ..:..! 

I 20-0 ..:..! 

m 10-0 ..:..! 

n 5-0 ..:..! 

o 2-0 ..:..! 

p 1-0 ..:..! 

were exposed to an indefinitely small depth of fresh water, 
oxide of zinc was formed from the moment of expo.sure, on all, 
which formed hard mam miliary concretions on the surface of the 
zinc, and also in isolated centres on that of the iron ; but from 
the ratio of equal surfaces of zinc to iron, up to the proportion 



ON THE ACTION OF AIR AND WATER UPON IRON. 2o;> 

of thirty times the surface of zinc to that of iron, complete 
electro-chemical protective power could not be procured even 
for a few hours. With equal surfaces of zinc and iron the 
latter became red-rusty in twelve hours, in tubercular masses, 
the oxide formed having the composition (Fe O + Fcc, O3) 
+ H O. 

232. From the foregoing series of experiments on the re- 
actions of fresh and sea water on iron and zinc, besides the 
immediate facts obtained, we are in a condition to make some 
genera] deductions. It has been shown that the oxidizing 
effect of fresh water, holding one volume in eight of air and 
carbonic acid, is much greater than that of sea water, holding 
one volume in seventy of air and carbonic acid, on cast iron, 
wrought iron, and steel, in voltaic contact with zinc, all other 
things being the same ; this arises from two circumstances — the 
difficulty with which a saline solution absorbs air when once 
robbed of it, but still more from the fact, that the oxide of zinc 
formed plays a very diffei'ent part in sea water to what it does 
in fresh water. 

233. In sea water the oxidation of the zinc produced oxide 
(Zn O), and at length a coat of suboxide, which forms a dis- 
tinct dai-k gray layer on the zinc surface, and may be detached 
on bending the metal so as to obtain the suboxide in a state of 
complete insulation from admixed metal, but none of the first 
adheres to the metallic surface ; the whole of the oxide of zinc 
formed is either washed away in a pulverulent form, or is dis- 
solved by decomposition of the sulphates, bromides, and chlo- 
rides of the sea water, forming sulphate, bromide, and chloride 
of zinc, while the lime and magnesia form, with absorbed car- 
bonic acid, insoluble carbonates 5 or if the iron be peroxidized, 
the oxide of zinc forms in part a saline double oxide with the 
sesquioxide of iron ; but the zinc surface is preserved clean 
and uniform to the last, either in the metallic state or as a sub- 
oxide, except when the reaction has been very slow and the 
electrical current very feeble ; in which case, after the lapse of 
a long period, crystals of calc spar form on both metals. 

234. Not so, however, in fi'esh water; here the oxide of 
zinc undissolved forms local concretions of oxide on the sur- 
face of the metal already covered with -a coat of suboxide. 
Now the precise condition constituting a suboxide, as Bei-ze- 
lius has well remarked, is to be decomposed, under the play of 
very slight af&nities, into protoxide and metal, as in the ana- 
logous cases of the suboxides of copper, bismuth, arsenic, &c., 
at each local centre of deposition, then of protoxide of zinc, 
the suboxide is so decomposed in fresh water, attended with 



256 REPORT — 1840. 

decomposition of the water itself; hence results local action 
on the zinked surface, between the portions of it in the metallic 
state and in the state of suboxide or protoxide ; and hence its 
removal in patches, by which the iron is soon laid bare in 
spots, on which, when once peroxide of iron has formed to a 
certain extent, the protective power of the remaining zinc is at 
an end; for as has been shown*, the original difference in 
electric condition betvAeen clean iron and clean zinc is so small, 
that the former ceases to be negative with reference to tlie 
latter as soon as it has been rendered more positive by the pre- 
sence of its own peroxide. 

235. We have seen that the conditions the most favourable 
possible for rapid oxidation of iron consist in its exposure to 
" wet and dry," or to air covered with an indefinitely thin 
film of water constantly renewed ; thus circumstanced, zinc has 
no protective power over iron in fresh water ; and on the whole 
it mav be affirmed, that under all circumstances zinc has not yet 
been so applied to iron to rank as an electro-chemical protector 
towards it in the strict sense; hitherto it has not become a prevent- 
ive, but merely a more or less effective palliative to destruction f. 

236. There are some contingent circumstances in the re- 
actions of zinc and iron, in presence of air and water, which 
require a brief notice. All the surfaces of a parallelopiped of 
iron, in contact with zinc, do not lose alike by oxidation ; in 
these circumstances, that surface which is nearest to the source 
of absorbed atmospheric air, especially if it be parallel to the 
plane of the surface of the fluid, loses the most by oxidation in 
a given time. 

237- AH other circumstances being equal, the upper surface 
of a parallelopiped of iron loses more in a given time than 
either of the others. The reason of this is, that the bubbles of 
hydrogen escape freely from the upper surface as soon as 
formed, and leave it constantly exposed to the action of the air 
and water; but they cling to the lateral and under surfaces, 
and so defend them more or less from the reaction. The same 
result is frequently observable in a piece of iron exposed to a 
moist atmosphere, but from a different reason ; here, in general, 
dew deposits first and most copiously on the upper surface, and 

* § 207. 

t It is scarcely therefore necessary to notice, in way of contravention, a 
paper in Po^gendorff's Annalen for last year, vol. xlvii. p. 213, giving an 
account of the complete preservation of certain salt-pans by bands of zinc, 
which are said not to have been in contact with the saline solution. The 
paper in question is a curious instance of the " sophisma non causcB pro 
causa." A recently-boiled satiu'ated solution of common salt has no action on 
iron, whether zinc be present or absent. 



ON THE ACTION OF AIR AND WATER UPON IRON. 257 

hence it is the more moistened, and therefore the more cor- 
roded. These modifying conditions apply, whether iron be in 
contact with zinc or not. 

238. Water is always decomposed by iron or zinc in metallic 
contact as soon as oxidation of either metal has commenced, 
and hydrogen is at first absorbed by the water, and when this 
is saturated, evolved ; but oxidation will not commence at all 
either on metal in an hermetically sealed vessel of water free 
from air, or on a body acting in its capacity as a peroxide. Hence, 
while air is constantly requisite to maintain the power of de- 
composing the water, it is not by the decomposition of the air 
alone that the iron or the zinc is oxidized, as was maintained 
by Dr. Marshall Hall*. 

239. In my former Report f, I alluded to the effect of 
covering surfaces of neutral solids, as glass, &c. (beneath which 
the solvent fluid penetrated), in arresting corrosion. In the 
progress of these experiments, however, I have observed some 
curious modifications of this condition. 

240. If a clean surface of iron immersed in water be covered 
with a parallel surface of plate glass, leaving a film of water 
between, oxidation will not take place between the glass and 
the iron, at least for a great length of time ; it very gradually 
creeps inwards from the edges, forming patches of green inter- 
mediate oxide ; but if in place of the plane of glass a glass lens 
of large curvature, and thus making very small angles with the 
surface of the iron, be placed upon it, oxidation will commence 
at the point of contact, and will spread from thence, although 
the iron may be in such a condition, that if no glass or other 
neutral solid were in contact with it at all, oxidation would 
just not take place. 

241. So that, in general, whether a neutral solid prevent or 
promote oxidation, depends upon its position in relation to the 
surface of the metal. This fact seems to belong to the as yet 
not understood power, in promoting chemical action, which 
extremely small orifices or fissures seem to possess, as in the 
action of spongy platina, of pyrophorus, of porous bodies in 
the condensation and the diffusion of gases, endosmose and 
exosmose through capillary tubes, and so forth. It has long 
been observed, that in a crystallizing solution, crystals first 
form at acute angles and on salient points. 

242. If a plane of polished iron, or other oxidable metal, be 
fixed, forming a very acute angle with a plate of glass, ivory, 
&c., and both plunged into water, oxidation commences at the 
angle first and spreads from it, whatever be the position of the 

* First Report, § 11. t § 121. 

1840. s 



258 REPORT— 1840, 

angle with reference to the horizon. If the angle be formed by 
two planes of iron, the same results follow. If a cut be made 
on a plate of polished steel with a diamond, oxidation takes 
place there first. Hence, in general, a rough plate of iron or 
steel will be acted on by air and water sooner than a smooth or 
polished one ; and thus we perceive, in instruments of pre- 
cision, the value of a well-polished or burnished surface. 

243. The well-known difference in rapidity of solution be- 
tween pure zinc and that containing an alloy of another metal 
in small quantity, first noticed by De la Rive, induced me to 
make a few experiments as to whether the protective power of 
zinc to iron could be exalted by alloying the former with a mi- 
nute quantity of another metal, higher or lower in the electro- 
chemical scale. The following alloys were accordingly made, 
and equal surfaces of cast iron submitted to the action of sea 
water, immersed in metallic contact with these, viz. 



50 Zn 


+ 


Hg 


100 Zn 


+ 


Ap 


25 Zn 


+ 


Cu 


50 Zn 


+ 


Cu 


100 Zn 


+ 


Cu 


50 Zn 


+ 


Sn 


100 Zn 


-t- 


Ni 


25 Zn 


+ 


Fe 


100 Zn 


+ 


Na 



and also with pure zinc, and alone : on examination, it was 
found that the alloy, in minute quantity of every metal which 
is electro-negative to zinc, when in contact with cast iron, in- 
creases its corrosion in sea water, including the alloy with iron 
itself. While the alloy in minute quantity of a metal electro- 
positive to zinc increases its protective power to iron, or de- 
creases the corrosion of iron in sea water when in contact 
therewith ; we shall hereafter see reason to conclude these alloys 
not to be definite combinations, at least of their entire mass, 
although fused together in atomic proportion, but mixtures of 
definite alloys with a great excess of zinc. 

244. I now proceed to notice the results contained in Tables 
IX. and X. These tables indicate the amount of corrosion of 
cast iron in sea water, when exposed in voltaic contact with 
various alloys of copper and zinc, and of copper and tin, or 
with either of those metals separately per unit of surface. The 
alloys in Table IX. of copper and zinc, belong to the class of 
those generally called brass, those of Table X. to those usually 
denominated srun-metaL 



ON THE ACTION OF AIR AND WATER UPON IRON. 259 

The primary object of these two series of experiments was 
to determine, in all its generality, the question as to the pre- 
servative or non-preservative power of brass or gun-metal to 
iron in sea water, a statement affirmative of which, it will be 
recollected, was made at the meeting of the British Association 
at Liverpool. This question lias been pretty fully discussed in 
my previous report, and it was therein shown that neither brass 
nor gun- metal, as commonly so called, had any protective 
power (of an electro-chemical character) over iron in water, 
but, on the contrarj', promoted its corrosion. The few experi- 
ments on M'hicli this limited conclusion was made, were tried 
on alloys of uncertain, or at least non-atomic constitution ; it 
was desirable not merely to set the question of protective power 
finally at rest, but to establish a set of practical data for the 
engineer as to the actual amount of increment or decrement of 
corrosion of iron due to the presence of various alloys of the 
orders brass and gun-metal, when immersed in sea water. 

245. It is obvious that this question is only a particular case 
of a much more general one, namely, if there be three metals, 
A, B and C, whereof A is electro-positive, and C electro- nega- 
tive with respect to B, and capable of forming various alloys, 
A-l-C, &c. ; then if B be immersed in a solvent fluid in pre- 
sence of A, B shall be electro- chemically preserved, and A cor- 
roded, and vice versa. If B be so innnersed in presence of C, 
B will be dissolved or corroded, and C electro-chemically pre- 
served, the amount of loss sustained in either case by the posi- 
tive metal being determined according to Faraday's general law 
of volta equivalents. 

But now let various alloys be formed, having atomic constitu- 
tions, as 2 A + C, A + C, A + 2 C, &c., and let B be exposed 
to the same solvent in presence of each. Query, what will be the 
electro-chemical relation of the metal B to each alloy, in I'espect 
to preservation, or amount of loss by corrosion ? and what will 
be the nature and amount of the reactions of several such alloys 
upon an acid or saline solution, of a third metal, or of either 
of those constituting the alloys ? thus, 

246. When the metals, zinc and lead, and their alloys, having 
the compositions (4Zn + Pb) , (3 Zn -f Pb), (2 Zn + PI)), (Zn + Pb), 
(Zn-f-2 Pb), {Zn + 3 Pb), (Zn-f 4 Pb), are immersed under simi- 
lar circumstances in a solution of acetate of lead, it would be 
presumed that the decomposing power of every alloy would be 
in proportion to the quantity of zinc entering into its composi- 
tion. The result is not so, however. The zinc and the alloys 
(4 Zn + Pb) and (3 Zn + Pb) at once reduce the lead of the acetate 
of lead to the state of metal, and as rapidly as zinc alone ; after 



260 REPORT — 1840, 

the lapse of some days, the alloys (2 Zn + Pb), (Zn + Pb), iind 
(Zh + 2 Pb) have reduced a few scattered crystals of lead ; but 
the remaining- alloys, (Zn4-3 Pb) and (Zn + 4 Pb), act in all re- 
spects precisely as the lead itself towards its own salts. 

21 7 • When a similar set of alloys are placed in a solution of 
nitrate of copper, a metal which is reduced from its salts both 
by zinc and lead, then the zinc and the alloys (4 Zn + Pb) and 
(3 Zn + Pb) reduce the nitrate to metal, and the lead does so 
likewise. The alloys (2 Zn + Pb), (Zn + Pb), and (Zn + 2 Pb) 
reduce the salt to deutoxide and metal mixed ; but the alloys 
(Zn + 3 Pb) and (Zn + 4 Pb) reduce the nitrate to deutoxide alone, 
without reduction of metal. From the relations in affinity for 
oxygen between copper, zinc and lead, it was to be presumed, 
that all the alloys of the two latter metals w^ould reduce copper; 
but it is remarkable that all the alloys between (2 Zn + Pb) and 
(Zn + 4 Pb) have less power of reduction than lead alone, while 
the alloys (4 Zn + Pb) and (3 Zn + Pb) have at least equal power 
with zinc alone. 

Analogous phsenomena occur when solutions of other metals, 
reducible by either zinc or lead, are used; and also when other 
metals, as the alloys of copper and zinc, or copper and tin, are em- 
ployed, so that no prediction can be made, from the known affini- 
ties of the component metals towards a saline solution, what shall 
be the affinities towards the same solution of their atomic alloys. 

248. In this class of reactions it by no means always happens, 
that both metals of the alloy, although both separately soluble in 
the electro-negative element of the saline solution experimented 
on, are dissolved in the ratio in which they exist in the alloy ; 
nor is it always the most electro-positive metal of the two of 
which the largest amount is dissolved. The presence of each 
metal, and of its oxides, affects the affinities of the other of them, 
instances of which we have in the alloy of silver and platina, 
soluble in nitric acid, &c. As, however, the treatment of the 
general question of the action of alloys, when immersed in acid 
or saline menstrua on the solvent, and on each constituent metal, 
does not properly belong to the present subject, and a sufficient 
general indication of their bearing upon it has been given, I re- 
serve the details for another occasion, and pass on to remark the 
practical uses to the engineer of Tables IX. and X. 

249. In Table IX. it vvill be seen that the twelfth column gives 
the amount of loss per square inch of surface of cast iron, with 
the skin removed by turning or planing (during a period com- 
parable with all the preceding experiments), in contact with 
brass, and various analogous alloys of zinc and copper, and also 
with copper and with zinc singly. Thus the engineer is enabled 



ON THE ACTION OF AIR AND WATER UPON IRON. 261 

to predict the amount of loss an)'' piece of submerged iron- work 
will sustain in a given time by corrosion, when brass, &c. enters 
as part of the construction, as, for instance, in the rollers, chain- 
boxes, paddle-sluices, &c. &c. of dock-gate work. 

It will be seen that cast-iron alone, similarly circumstanced 
to all the rest (No. 24), suffers a loss in sea water, as compared 
with an equal surface of cast iron in contact with copper, as 
8-23 : 11 '37; that is, the copper, as might be expected, largely 
promotes the corrosion of the iron ; but the Table also shows, 
what would not have been expected, that the alloy having the 
composition (7 Cu.+ Zn), promotes this corrosion still more 
powerfully, or in the ratio of 13'21 : 8-23, so that the addition of 
this amount of an electro-positive metal to the copper actually 
produces an alloy (a new metal, in fact), with higher electro- 
negative powers in respect to cast iron than copper itself. The 
Table shows that copper, and every alloy of it, with zinc, from 
(Zn + 10 Cu) to (17 Zn-<-8 Cu) inclusive, are electro-negative 
with respect to cast iron ; but that every alloy from (18 Zn + 8 Cu) 
to (5 Zn + Cu) inclusive, with zinc itself, are electro-positive with 
respect to cast iron. Now the last but one of the electro-nega- 
tive alloys is that (2 Zn + Cu), which is the usual composition 
of British brass of commerce, which, while it does actually by 
its presence increase the corrosion of iron by menstrua, thus 
fortunately does so in a small degree, as compared with other al- 
loys containing more copper. 

250. It will be perceived that the alloys from (l7 Zn + 8 Cu) 
to (23 Zn + 8 Cu) form a separate interpolated series, advancing 
each by one eighth of an atom, and differing by only a single atom 
of zinc from the alloy (2 Zn H- Cu) which precedes, and from that 
(3 Zn + Cu) which follows. This was needed, and prepared after 
the formation of the other alloys, in order to discover the alloy of 
no action, as it may be termed, or that which, in presence of iron 
and a solvent, would neither accelerate nor retard its solution ; 
and accordingly we see it lies between (17 Zn-|-8 Cu) and 
(18 Zn + 8 Cu), the former being slightly electro-negative, and 
the latter slightly electro-positive, with respect to cast iron. 

251. It was stated in the former report, that the really import- 
ant direction in which to look for protection from corrosion of 
iron in water was indicated by some results of Schonbein, An- 
drews, Payen and other experimenters, and that the problem 
was "to obtain a mode of electro-chemical protection, such, that 
while the metal (iron) shall be preserved, the 2^^otector shall 
not be acted on, and whose protection shall be invariable*." 

This view Professor Schonbein himself, in a paper presented to 
* Report, § 136. 



262 RE POUT — 1840. 

the Chemical Section of the British Association at Birmingham, 
passes summary judgment upon, by affirming that " the con- 
dition, shic qua non, for efficaciously protecting readily oxidable 
metals against the action of free oxygen, being dissolved in fluids, 
is to arrange a closed voltaic circle, 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 
containing hydrogen — for instance, water." Whatever opinion 
may be formed as to the necessity of a closed circle, it is un- 
doubtedly not proved that the evolution of hydrogen is the con- 
dition of protection, sine qua non ; the experiments adduced do 
not show it, while many others might be quoted directly show^- 
ing it not to be a necessary condition. This is not, however, the 
place for discussing Professor Schonbein's views at length, which 
involve the whole qnastio vexata of the chemical and contact 
theories of galvanism. 

252. I proceed, therefore, to notice the seventh column of 
this Table, in which is given the loss of weight sustained by the 
alloys of copper and zinc while in presence of cast iron and the 
solvent. On inspecting this column it will be apparent that 
the losses l^ave not taken place in accordance 'with the law 
of volta-equivalents : there can be little doubt that they are 
strictly in accordance Mith that law, and that the results are ir- 
resolublc from the involvement of two or more series in column 
seven, arising probably from some of the alloys being simple 
binary compounds, and others either double binary alloys, or a 
mixture of a binary alloy with one or other of its components in 
excess. 

253. It w'ill be further observed, that whereas zinc alone in 
protecting cast iron suffered a loss of = 2*95 grains, being 
nearly the equivalent, the alloy (23 Zn -\- 8 Cu), which as fully 
protected the iron from all action or corrosion, sustained a loss 
but of =0'51 grain; in other words, the protecting metal was 
scarcely itself acted on at all. 

This, then, makes a by no means unimportant step towards 
obtaining the much-wished-for electro-chemical protector before 
spoken of; and henceforth the engineer will have it in his 
power, whenever the alloy (23 Zn + 8 Cu) can be used or applied 
in contact with cast iron, to protect the latter as fully as by 
zinc itself; yet with a protector which shall suffer scarcely 
any loss, and whose protective energy I have reason to suppose 
will be, from this very cause, much more permanent and inva- 
riable than I have already proved that of pure zinc to be. 

254. With respect to the allojs themselves found in this 
Ninth and following Table, I believe so large and complete a 



ON THE ACTION OF AIR AND WATER UPON IRON. 263 

collection of strictly atomic alloys of the two practically impor- 
tant classes of brass and gun-metal has not been made hereto- 
fore. 

The principal experiments on the properties of this class of 
alloys published, are those of Margraff; but his were not 
atomic alloys, nor made in a way likely to ensure a knowledge 
of their constitution. I have therefore deemed it worth while 
to make some experiments on the properties of these alloys, and 
have given the results in Tables XIV. and XV. : as these nearly 
explain themselves, it is necessary to make but few remarks on 
them. The alloys of zinc and copper were all made in close 
vessels ; the copper was fused first, the zinc in another part of 
the same bent wrought iron tube, coated and lined with porce- 
lain clay and plumbago. The zinc was gradually brought in 
contact with the copper : the apparatus excluded air, and was 
continually agitated, until the alloy was poured into a mould of 
cast iron, in which it was cast into a long strip, which solidified 
instantly. About seven pounds weight of each alloy were formed 
at once, and the constitution of each, where any cause of doubt 
existed, was verified afterwards by an assay. Their composition 
therefore is rigidly assigned — a circumstance which it is con- 
ceived gives their properties, so far as they have been ascer- 
tained, more than usual value. 

255. The modulus of cohesion given is higher considerably 
than those found by Sir John Rennie for copper and brass 
(2Zn + Cu), or commonly assigned to zinc. I have no doubt, 
however, of the present being correct, and the difference arises 
probably from the superior purity of the metals used by me. 

256. The immediate change by the addition of only one 
eighth of an atom of zinc to the alloy (2 Zn + Cu), from a tough 
yellow alloy to a white one of extreme brittleness, is very re- 
markable. The alloy (5 Zn + Cu), and all the alloys of copper 
and zinc having more constituent zinc than (17 Zn + 8Cu) are 
electro-positive to cast iron, or protect it in solvents ; yet M'hen 
the alloy of copper is reduced to the ratio of (25 Zn + Cu), or 
(100 Zn + Cu), the compound becomes again electro-negative to 
cast iron*. These indicate, in a forcible manner, that these 
latter are not simple alloys, but mixtures. It may be added, 
that the I'eduction to the law of volta-equivalents of the losses 
in the seventh column, may enable us to discover what is the 
constitutional arrangement of the alloys themselves. 

257. It should be remarked, before leaving the subject of 
these alloys of Zn + Cu, that their specific gravities, as experi- 

* § 243. 



264 REPORT — 1840. 

mentally obtained in coiuinn five, do not follow the ratio of the 
amount of copper, increasing as it increases, although tlieir 
general tendency is towards this ; the greatest perturbations 
take place in theinterpolatedseries(]7Zn + 8Cu)to(23Zn-)- SCu). 
These specific gravities are taken on the alloj^s just as they were 
cast, and suddenly cooled in the cast-iron mould ; but on sub- 
mitting some of them to lamination, very variable amounts of 
condensation took place. Hence it is probable that sudden 
cooling produces an effect analogous to tempering in cold water 
on the alloys of copper and zinc. Dussaussoy found that as 
the latter became soft and malleable by tempering {tronpe), 
their specific gravities were reduced in variable proportions ; 
and it matters not whether this tempering be effected in water, 
or by sudden cooling in a metallic mould ; the alloys now in 
question have therefore been submitted to this process ; and as 
no link at present exists connecting the density of such an alloy 
with its specific gravity after lamination, the densities now given 
ill Tables XIV, and XV. will be found, in most instances, not 
to correspond with those occasionally given in books, and 
which have been chiefly made on alloys submitted to compres- 
sion, or cast and cooled in various wavs. The densities given, 
however, are I believe close approximations to the truth ; and 
all the alloys having been cast in the same way, at the same 
temperature, and cooled at the same rate, these specific gravities 
must be relatively correct. 

258. Table X. contains the results of the action of sea 
water on cast iron, in presence of copper and tiiij or their alloys. 
What has been said of the preceding explains the general na- 
ture of this Table also. It is therefore only necessary to re- 
mark here, that as copper and tin are each singly electro-negative 
with respect to iron *, they both, together with every alloy in 
the Table, increase or accelerate the rate of corrosion of cast 
iron in a solvent, though in every variable degree. 

The maximum increase is produced by tin alone ; which in- 
dicates that tin is more powerfully electro-negative to cast iron 
than copper, contrary to the opinion previously held. The in- 
crease of corrosion produced generally by alloys of copper and 
tin is far greater than by those of copper and zinc : hence the 
important practical deduction, that when submerged iron-works 
must be in contact with either alloy, common brass, or copper 
and zinc is much to be preferred to gun-metal, although con- 
trary to general practice amongst engineers. 

The losses on these alloys in column seven, as in the former 
case, do not apparently follow the law of volta-equivalents. 
* Report, § 96. 



ON THE ACTION OK AIR AND WATER UPON IRON. 265 

259. The ratio of the surface of the cast-iron parallelopipeds 
used in these two sets of experiments to that of similar slips 
of the alloys, is given : both iron and alloys were filed to an ex- 
act gauge, so as to present strictly equal surfaces, in pairs, and 
the former made all of equal weight. The amount of loss or 
the " index of corrosion " of cast iron in contact with any given 
alloy in the Tables, will of course vary according to some un- 
ascertained function of the surface of the alloy and of the iron 
exposed to chemical action. The law regulating this remains 
to be developed ; it is a subject of considerable complexity and 
experimental difficulty. The ratio, however, of surface of the 
electro-negative to that of the electro-positive metal, may vary 
to a considerable extent without very materially affecting the 
results given in the present Tables, as respects their primary 
object. 

260. These experiments were necessarily made in a limited 
quantity of sea water (12 cubic inches each), and all in separate 
glass vessels ; and as this water was soon exhausted of much of 
its previously combined air, the eleventh and twelfth columns 
in each Table give the ratio of the actual corrosion in a limited 
quantity of water to that which would take place in an unlimited 
one, or in the open sea, which is deduced from the result of 
(a 77) in Table I. first series, being on the same sort of cast 
iron as the present. 

261. There are several collateral points of scientific interest 
this branch of our inquiry presents, which I pass, as out of the 
subject of inquiry. I would remark, however, that the results 
confirm fully what had been previously stated respecting the 
impossibility of protecting iron by brass in the ordinary sense of 
the word. They also point out the inutility, not to say the ab- 
surdity, of some inventions for the so-called prevention of ox- 
idation, for which patents have recently been obtained ; for ex- 
ample, more than one patent for so preserving iron by dipping 
it into melted copper *, or coating it with copper or brass in 
various other waysf. 

262. It has recently been proposed to substitute zinc for 
lead in the operation of " cramping," or running a fluid fusible 
metal into the joints of iron-works to secure them together, or to 

* Repertory of Arts for 1839-40. 

t I observe with pleasure that M. Karsten of Berlin has recently published 
{V Inst'dut, No. 275, April 1839) some experiments on the electro-chemical re- 
lations of alloys of copper and zinc, &c., to solutions of their own metals. It 
is to be regretted that liis experiments do not seem to have been made on 
alloys of atomic constitution ; but while unknown to each other travelling 
(though with different objects) on neighbouring roads, it is pleasant to find 
that our results have so far brought us to the same resting-place. 



26G RKPORT — 1S40. 

other materials, in order, by taking advantage of its positive re- 
lation to iron, to save the latter from the increased corrosion 
due to the presence of lead, which is strongly negative to it. 

Zinc alone, however, possesses some disadvantages as a 
" cramping " metal ; it oxidates with great rapidity when fused 
in an open vessel ; it contracts more than lead on solidifying, and 
it is too rigid to permit subsequent " caulking," so as to cause 
it again to till the cavity into which it was cast. The results 
which have been given for the alloys of zinc with copper render 
it extremely probable, however, that an alloy of zinc and lead 
might be formed eminently suitable as a " cramping metal " in 
contact with iron, which, while it should possess the requisite 
physical properties, would be found in such a relation to iron as 
to retard, or at least not promote, its oxidation. 

263. In my previous report* I suggested the possibility of 
preserving electro-chemically, to a greater or less extent, the 
dense and hard gray cast irons in ordinary use for engineering 
purposes by means of contact with the softest and most carbo- 
naceous cast irons, such as those of Scotland and Ireland. I 
showed that the latter sort of cast iron is, in presence of a sol- 
vent, constantly in an electro-positive relation to the former, 
and that of two such specimens of cast iron, in voltaic contact, 
there was reason to believe that the denser iron would be pre- 
served to a greater or less extent at the expense of the other. 
Experiments on this subject have now been in progress for 
twenty-five months. 

264. When four equal-sized parallelopipeds, two of very hard 
dense bright gray cast iron, just capable of being planed or 
turned, and two of soft dark gray and highly carbonaceous cast 
iron, are placed, one of each pair, separately in a jar of sea 
water, and the other pair (viz. hard and soft) in a jar of sea 
water together, and in voltaic contact, the pieces having been 
all weighed, and the sea water preserved at a constant level, 
&c. &c. Then, after a period of twenty-five months had elapsed, 
on examination the following were found to be the results as to 
corrosive action : — 

All the pieces were found covered with a coat of red oxide, 
having the composition = {Fe^ Og) + (Fe O -f- C Og) -f^H O, 
and much of the same had deposited in the glass vessels. 

265. The piece of hard cast iron immersed singly was found, 
on washing off the coat of rust, clean and pretty bright, and its 
surface still metallic. On weighing, and also measuring by a 
micrometer, it was found to have lost a coat of iron over its 

* § 129. 



ON THE ACTION OF AIR AND VVATJiR UPON IRON. 267 

whole surface of 0*007 of an inch in depth, a result also con- 
firmed by the amount of rust contained in the vessel, and on 
the piece when reduced to peroxide. 

266. The piece of soft cast iron immersed alone was found, 
on washing off the coat of rust, to be covered with a thin coat 
of soft, unctuous plumbago, capable also of being washed away 
by rubbing with the finger ; its surface was black, and filled 
with glittering minute scales of graphite, but had lost its me- 
tallic lustre wholly. On removing the plumbago down to the 
solid iron, by rubbing with a piece of hard wood and washing, 
the piece was found to have lost a metallic coat over its whole 
surface of 0*01 of an inch in depth, estimated as before, and 
controlled by the amount of graphite and rust reduced to 
peroxide. 

267. Lastly, the voltaic couple, the hard and the soft iron in 
contact, were examined ; on washing off the rust, the hard 
specimen appeared bright and polished, and some minute file- 
marks on its surface, as sharp as when placed in the sea water. 
The surface of the soft piece of cast iron, on the contrary, was 
black, full of scales of graphite without metallic lustre, and 
capable of being rubbed away with the finger. The two sur- 
faces, which were actually opposed to each other and in contact, 
were iii both almost quite free from stain or oxidation, where 
air and water with difficulty gained access, from reasons before 
explained. On washing and cleaning perfectly the hard speci- 
men from oxide, and the soft one from oxide and plumbago, 
and weighing as before, the hard cast iron was found to have 
lost a coat of iron over its whole exposed surface = 0*00263 of 
an inch in depth, while the piece of soft cast iron had sustained 
a loss over its whole exposed surface of 0*03 of an inch in 
depth, both estimated as before, by weighing and measurement, 
and the result controlled by estimation of the pei'oxide and 
graphite produced. 

268o It is hence proved, that the softest dark gray cast iron is 
sufficiently electro- negative, to hard bright gray cast iron, to re- 
tard the corrosion of the latter in sea water when voltaically as- 
sociated with it, to the extent of two thirds of the total amount of 
corrosion that would be experienced by the same hard gray cast 
iron, if exposed for the same time and under similar circum- 
stances alone to sea water, and that the formation of plumbago 
on the softer iron or positive pole, and the collection of a coat 
of rust on the surface of both irons, does not prevent, although 
it may possibly in some degree interfere with, this effect. 
Hence it follows, that while the voltaic relations of soft to hard 
cast iron are such as will not prevent oxidation upon either, it 



2GS REroRT — 1840. 

is yet in our power greatlj' to retard the corrosion of the harder 
iron at the expense of the softer, so that the engineer is thus 
given a principle of guidance in the combination of different 
"makes" or sorts of cast iron in the same structure, when it 
may be desirable partially to preserve some parts at the expense 
of others of less structm-al importance*. Instances of such 
cases, and of the applicability of the principle here given, will 
at once occur to practical men. 

269. The engineer of observant habit will soon have per- 
ceived, that in exposed works in iron, equality of section or 
scantling, in all parts sustaining equal strain, is far from in- 
suring equal passive power of permanent resistance, unless, in 
addition to a general allowance for loss of substance by corro- 
sion, this latter element be so provided for, that it shall be 
equally balanced over the whole structure ; or, if not, shall be 
compelled to confine itself to portions of the general structure, 
which may lose substance M'ithout injuring its stability. 

The principles we have already established sufficiently guide 
us in the modes of effecting this ; regard must not only be had 
to the contact of dissimilar metals f, or of the same in dis- 
similar fluids I, but to the scantling of the casting and of its 
parts §, and to the contact of cast iron with wrought iron or 
steel, or of one sort of cast iron with another ||. Thus, in a 
suspension bridge, if the links of the chains be hammered, and 
the pins rolled, the latter, where equally exposed, will be eaten 
away long before the former. In marine steam-boilers, the 
rivets are hardened by hammering until cold ; the plates, there- 
fore, are corroded through round the rivets before these suffer 
sensibly, and in the air-pumps and condensers of engines work- 
ing with sea water, or in pit work, and pumps lifting mineral- 
ized or " bad" water from mines, the cast iron perishes first 
round the holes through which wrought-iron bolts, &c. are in- 
serted. And abimdant other instances might be given, showing 
that the effects here spoken of are in practical operation to an 
extent that should press the means of coimteracting them on 
the attention of the engineer. 

270. I have not yet been enabled to extend this part of the 
inquiry to fresh water, but have reason to suppose it would not 
be in such case attended with equally striking results from 
facts before stated with respect to zinc and iron in contact in 
fresh water ; the same forces, however, still will operate with 
like results, only differing in degree. It seems not improbable, 

* Report, § 134. f § 244—261. % § 157. 

§ Sect. 179—183. || § 263—268. 



ON THE ACTION OF AIR AND WATER UPON IKON. 269 

that the softer cast irons might be alloyed with a minute quan- 
tity of some other metal, which should produce a compound 
still more electro-positive with respect to hard cast iron than 
before. This view is supported by some facts recorded by Ber- 
thier, in the Annales des Mines, torn. xi. p. 512, third series. 
Soon after Algiers was taken by the French, some ancient shot 
and shells were sent to France to be recast, which had been 
discovered in the arsenal. They were found, however, unfit for 
service ; the metal of which they were composed was full of mi- 
nute cavities, so brittle as to be easily pulverized, white and 
lamellar. Analyses of the shot and shells gave the following 
results in 1000 parts : 

Shot. Shells. 

Arsenic . . , 0*270 . . . 0-098 
Carbon . . . 0*010 . . . 0-015 



0-280 0-113 

They contained neither sulphur, manganese, calcium, nor sili- 
con. Specific gravity of shot = 7 '650, of shells = 7 "5 85. 
The cast iron alloy of which they were formed was found by 
Berthier to oxidate, when exposed to air and tvater, with un- 
usual rapidity : he supposes these projectiles to have been cast 
in Spain, of iron made from mispikel or arseniuret of iron. 

271. I now proceed to make some remarks upon the specific 
gravities of cast iron, wrought iron, and steel, which follow in 
the accompanying tabulated results. In Table XI. are col- 
lected the specific gravities of all the cast irons of the preceding 
experiments. These specific gravities have been taken with an 
unusual amount of care, and by a new method, described in 
the former Report*, which possesses some decided advan- 
tages in point of accuracy and convenience. They have all 
been taken on equal- sized cubes of the several cast irons cut 
by the planing-machine from bars of equal size, viz. one inch 
square, and cast in the same way, at the same temperature 
nearly, and cooled at the same rates ; all of which precautions 
are essential to procuring correct results, 

272. Many of my specific gravities do not agree with those 
given by Dr. Thompson or those of Mr. Fairbairn, contained 
in their respective reports f. This may arise possibly from Dr. 
Thompson's specific gravities having been taken from pieces of 
the raw pig-iron, or castings of a different size from those I 
used, or of various dimensions with respect to each other. In 
Mr. Fairbairn's case, probably from the circumstance that (as 

* § 71. t In vol. vi. Report of the British Association. 



270 REPORT— 1840. 

I have heard) his specific gravities were taken bj' weighing 
equal bulks ; cubes, in fact, cut from the mass of cast iron by 
the chisel and file, a method in itself not susceptible of much 
accuracy, but rendered much more liable to error from the 
liability to variable condensation of volume of the iron in the 
processes of chipping and filing ; a rough crystalline broken 
surface effectvially prevents an exact specific gravity being taken 
of cast iron by the usual method of weighing such a specimen 
suspended in M'ater ; and no cutting out of the specimen for 
weighing by any method is allowable, except by the lathe or 
planing-machine, which operate so quietly, that no condensa- 
tion of volume is likely to take place. 

273. Dr. Thompson's results give the specific gravity of hot- 
blast iron greater than that of cold- blast. Mr. Fairbairn's, on 
the contrary, give the specific gravity of cold-blast ii'on as the 
greater, and to the latter conclusion my own results tend. I have 
entii'e confidence in the correctness of the specific gravities I 
have given, from the method and precautions taken, and the ac- 
curacy of the instrument used in the weighings — a balance of 
Troughton's construction, readily sensible, when loaded, to the 
third decimal place. 

274. A correct knowledge of the specific gravities of cast iron 
is important in several respects to the engineer, but most of all 
so from the fact, that Messrs. Fairbairn's and Hodgkinson's ex- 
periments on the strength of hot- and cold-blast iron seem to in- 
dicate that the ultimate strength of cast iron is in the ratio of 
some function of the specific gravity, a view more recently also 
confirmed by Mr. Richard Evans's experiments on the strength 
of anthracite pig-iron. 

Now the conditions rendering the specific gravity of the same 
cast iron variable, are 

I. The bulk of the casting. 

II. The depth or head of metal under which it has been cast. 

III. The temperature at which the iron has been " poured," or 
run into the mould. 

IV. The rate at which the casting has cooled. 

The determination of the law governing the change in each 
of these cases is a work of some labour and difl&culty, which has 
been partly attempted, 

275. In Table XII. the results are given of the experi- 
ments I have made on Scotch, Welsh, and Staffordshire cast 
irons, showing the increase of density produced in large cast- 
ings at every two feet in depth, down to fourteen feet in depth 
of casting. These experiments were made on pieces cut at every 
two feet from a shaft or cylinder of four inches in diameter, cast 



I 



ON THE ACTION OF AIR AND WATER UPON IRON. 271 

vertically, in dry sand moulds. They show a very rapid increase 
at first, and, belove four feet in depth, a nearly uniform incre- 
ment of density, approximating to a common difference of 0-13. 

No previous attempts have been made, to my knowledge, to 
ascertain these conditions of variable specific gravity in cast iron : 
yet their importance is obvious ; for if the ultimate strength of 
castings is as some function of their specific gravity, the results 
of experiments in relation to strength of castings of different 
magnitudes, or cast under different heads, are not comparable, 
unless these conditions of specific gravity be attended to, and in- 
volved in every calculation. 

276. In Table XIII. the results are given of my experi- 
ments on the decrease of specific gravity of the same cast iron, 
due to increase of bulk or volume of casting, the circumstances 
of head of metal, temperature and rate of cooling being the same. 
The irons experimented on are Scotch, Welsh and Staffordshire. 
The bulk of the casting in each successive experiment is double 
that of the preceding one ; and the results show nearly an equal 
decrement in specific gravity in proportion to the increase of 
volume of the casting. 

These results sufficiently show, for instance, that although 
the strength of rectangular beams varies directly as their bi-eadth, 
yet doubling the thickness or breadth of such a cast-iron beam 
will not quite double its strength, as the same iron becomes less 
dense in the larger casting, if so be that we admit a relation be- 
tween density and ultimate cohesion, of which there seems to be 
but little doubt. 

277- In Table XI. I have arranged all the cast irons of 
my experiments in classes, according to the characters of their 
fracture, and, for the first time, attempted to establish an uni- 
form system of nomenclature in this respect, dividing all sorts 
of cast iron, by fracture, into one of six classes, either 

I. Silvery, 

II. Micaceous, {miratoire of French authors,) 

III. Mottled, 

IV. Bright gray, 
V. Dull gray, 

VI. Dark gray, 

which will be found sufficient to include and describe every va- 
riety ; and it is much to be wished that authors on these sub- 
jects would, in future, adopt this or some similar invariable no- 
menclature for the character of fracture, at present usually so ill 
described. 

278. The nomenclature, or classification of cast iron by frac- 



272 REPORT — 1840. 

ture here adopted, is more also than a mere set of arbitrary 
visual distinctions, inasmuch as each class I have made holds a 
constant relation between the character of its fracture and its 
chemical constitution. I have also given the general working 
character of each such class of cast iron, by which, however, it 
is not to be understood, but that occasionally a mixed cast iron 
may be found, possessing all these characters in working, and 
yet breaking with a slightly different fracture. The working 
characteristics given are, however, on the whole, correct. 

279. The present communication, I would hope, in some de- 
gree fulfils the desire of tlie British Association as to a poi-tion 
of this inquiry, and will be found not devoid of use to the prac- 
tical engineer. I do not purpose to enter at all in the present 
Report upon the chemical consideration of the changes which 
iron occasionally undergoes bj^ the action of various solvents in 
passing into a substance analogous to plumbago, nor of the or- 
ganic and other products which result from such reactions ; 
these I hope to bring forward on a future occasion, along with 
the results of all the other trains of experiment in progress or 
contemplation, and of the second immersion of all the cast and 
wrought irons for a period of two years, which will expire in 
January 1842. The results of their first immersion are now 
given, and with the results of the experiments now in progress, 
on wrought iron and steel, together with a review of the whole 
subject in its imrely chemical relations, will, I expect, com- 
plete our researches. 

280. The latter experiments on wrought iron and steel have 
been for some months in operation ; and the tables of data be- 
longing to them, which best indicate their nature and extent, 
have been presented ; but it is not necessary to publish them at 
this time, as the only results of this series actually completed as 
yet, are the specific gravities. These are given in Table XVI. 

The maximmn specific gravity is that of tilted blister steel, 
made by the Mersey Steel Company, which is = 7-8461. The 
minimum specific gravity is that of cast steel in the ingot, be- 
fore tilting, which is =,7'4413 ; it contains microscopic vesicles. 
The specific gravity of the iron from which both were made, is 
= 7-5839. 

From this Table it appears, that both in wrought iron and steel 
the density is increased more by hammering than by rolling, and 
that the densest specimens of both metals break with a fibrous 
or very fine crystalline fracture, while the least dense have a coarse 
crystalline or lamellar fracture. 

281. Experiments already detailed having demonstrated the 
great rapidity with which iron of every sort is corroded while 



ON THE ACTION OF AIR AND WATER UPON IRON. 273 

kept just covered with water, or between " wet and dry," a 
series of new experiments have been recently arranged, contain- 
ing specimens of cast and wrought iron, freely exposed to all the 
atmospheric influences, at Dublin. These are coordinate with 
all the experiments, whose first results of submersion are now 
given, and will connect the action of water containing air and 
carbonic acid on iron with that of air holding water and car- 
bonic acid in suspension, &c. ; and, as the meteorological regis- 
ters of Dublin are tolerably perfect, will be hereafter comparable 
with any such made in another locality. The data of this set of 
experiments may await the publication of a third report, and be 
given along with the results. 

282. In concluding this second report upon a subject in which 
I feel a lively interest, and the practical bearing of which needs 
no further evidence than the multitude of patents, whether good 
or bad, for inventions intended to preserve iron, &c., which have 
been obtained since the publication of the first report, and in 
retracing the ground already gone over, I must regret the many 
imperfections and omissions, which I might have been enabled to 
avoid, could I have devoted more time to these researches. That 
learned otium, however, so necessary to successful experimental 
study, is denied to those who, like myself, find every day to come 
preoccupied with the unavoidable duties of a laborious profession. 
Hence, most of these experiments have been made and recorded 
in hours stolen from rest, or, with greater difficulty, from busi- 
ness. 

I have to thank many individuals for specimens of iron, &c. 
in various conditions, and especially my young friend Mr. 
Charles Scanlan, for his valuable assistance in taking great 
numbers of specific gravities. 



1840. 



74 



REPORT 1840. 



Table 
Box a. No. 1. containing Specimens of Cast and Wrought 

Sunk and moored at the Second Buoy in from the Western Pier Head in three 
ordinarily 12 to 16 feet. Temperature of water 46° Fahr. to 58° Fahr. 
August 3rd, 1838. Weighed again and landed August 26th, 1839; hence 
1840, at one o'clock p.m., and now immersed. Specific gravity of water 

Box «. No. 1. Class No. 1. 



■ssss 



3 

4 

5 

6 

7 

8 

9 

10 

11 

12 

13 



Commercial Character of Iron. 



Hot or 
Cold 
Blast. 



External 

Character of 

Fracture. 



No. 1. Doulais ColJ 

No. 1. Doulais 1 Cold 

No. 3. Doulais Cold 

No. 3. Doulais j Cold 

No. 1. Doulais Hot 

No. 1. Blaenavon Cold 

No. 1. Blaenavon Cold 

No. 4. Doulais. Finery pig Hot 

No. 4. Doulais. Finery pig Hot 

No. 1. Pentwyn. Peculiar fracture. Hot 

No.l. Pentwyn. Peculiar fracture. [ Hot 

No. 2. Varteg Hill I Hot 

No. 2. Varteg Hill I Hot 



Dark gray 

Dark gray 

' Dark gray 

Dark gray 

Dull gray 

Dark gray 

Dark gray 

Silvery 

Silvery 

I Micaceous 

' Micaceous 

' Bright gray 

' Bright gray 



I Green 

Green 

Green 

Green 

' Green 

I Green 

j Green 

Green 

Green 

! Green 

j Green 

j Green 

Green 



Specific 
Gravity of 
Specimen 
Ws 

s = -— ■ 



7192 
7183 
7-159 
7-149 
7164 
7-143 
7-133 
6-378 
6-369 
7000 
6-991 
7074 
7-065 



Box a. No. I. Class No. 2. 



14 
15 
16 
17 



No. 1. Arigna Cold | Micaceous 

No. 1. Arigna Cold Micaceous 

No. 2. Arigna ; Cold Dull gray 

No. 2. Arigna Cold Dull gray 



' Green 


7-006 


1 Green 


7-015 


Green 


6-799 


Green 


6-809 



a 


18 


a 


19 


a. 


20 


et 


21 


a 


22 


a 


23 


s 


24 


a 


25 



Box «. No. 1. Class No. 3. Staffordshire, 



No. 3. Apedale. Cylinder Iron 

No. 3. Apedale. Cylinder Iron 

No. 1. Parkfield 

No. 1. MaJeley Wood 

No. 1. Lillieshal 

No. 1. Cinderford 

No. 1. Cinderford 

No. 1. Burchill's 



Hot 
Hot 



Cold 
Cold 
Cold 
Cold 



Mottled 
Mottled 



Cold ! Mottled 



Bright gray 
Dull gray 
Bright gray 
Bright gray 



Cold I Micaceous 



Green 


7106 


Green 


7116 


Green 


7-248 


Green 


7-115 


Green 


7-205 


Green 


7040 


Green 


7-049 


Green 


6-933 



i 



ON THE ACTION OF AIR AND WATER UPON IRON. 



275 



No. I. 

Iron, immersed in clear Sea Water, Kingstown Harbour. 

and one half fathoms water, at half tide, on a clean sandy bottom. Tide rises 
The length of the Box lies east and west. Sunk at one o'clock p.m., 
the period of immersion = 387 days. Sunk a second time January 11th, 
in Kingstown Harbour = 1027'80. 

Welsh Cast Iron. 





6. 


7. 


8. 


9. 


10. 


11. 


12. 


13. 








Weight of 


Total loss 


Loss of 


Loss of 


73 






Dimensions 


Weight of 


Specimen 


by 


Weight per 


Weight 


£ ^Q 


Character 




of 


Specimen 


after 


Corrosion 


square inch 


referred to 


tela t- 


of 




Specimen. 


in Grains. 


387 days' 


in 


of 


Standard 


m 


Corrosion. 








exposure. 


387 days. 


Surface. 


Bar. 






in. in. in. 


















5x5x1 


43011 


42720 


291 


4-16 


•392 


0- 


Uniform P. 




5 X 5 X -25 


11871 


11384 


487 


8-85 


-834 


0- 


Uniform. 




5x5x1 


43777 


43452 


325 


4-64 


-437 


0- 


Local pitted. 




5 X 5 X -25 


12665 


12209 


456 


8-29 


•782 


0- 


Local. 




5x4x1 


34843 


34469 


374 


6-45 


•608 


0- 


Uniform. 




5x5x1 


43558 


43200 


358 


511 


•482 


0- 


Uniform P. 




5 X 5 X -25 


12185 


11759 


426 


7-74 


•730 


0- 


Uniform. 




5x5x1 


41257 


41176 


81 


1-16 


•109 


0^ 


Tubercular. 




5 X 5 X -25 


10846 


10576 


270 


4-90 


•462 


0^ 


Tubercular. 




5X5X1 


41864 


41547 


317 


4-53 


•427 


0^ 


Uniform P. 




5 X 5 X -25 


11665 


11169 


496 


9-01 


•850 


0- 


Uniform P. 




5x5x1 


43785 


43638 


147 


2-10 


•198 


0- 


Local. 




5 X 5 X -25 


12929 


12339 


590 


10-70 


1-009 


7-0 


Local pitted. 




Irish Cast 


[ron. 
















5 X 5 X -25 


10922 


10479 


443 


8-05 


•759 


0- 


Uniform P. 




5x5x1 


40670 


40331 


339 


4-84 


•457 


0- 


Uniform P. 




5 X 5 X -25 


11886 


11453 


433 


7-87 


•742 


0- 


Uniform P. 




5x5x1 


42915 


42695 


220 


3-14 


•296 


0- 


Uniform P. 




Shropshire 


, and G 


ouceste 


r shire I 


rons. ( 


^ast. 








5x5 x-25 


12197 


11789 


408 


7-40 


•698 


0- 


Tubercular. 




5x5 X 1 


44690 


44352 


338 


4-83 


•456 


0- 


Tubercular. 




5x4 X 1 


34814 


34412 


402 


6-93 


•654 


0- 


Local. 




5x4 X 1 


34112 


33770 


342 


5-76 


•543 


0- 


Local. 




5x3-63x 1 


31818 


31530 


288 


5-37 


-507 


0- 


Local. 




5x5 x-25 


12454 


11900 


554 


10-07 


•941 


3- 


Local. 




5x3-75x 1 


32736 


32527 


209 


3-62 


-341 


0^ 


Local. 




5x3-5 X 1 


29617 


28773 


844 


16-23 


1-531 


0^ 


Local. 



T 2 



276 



REPORT — 1840. 

Box a. No. 1. Class No. 4. 



"~ = i; P 



Commercial Character of Iron. 



Hot or 
Cold 
Blast. 



External 

Character of 

Fracture. 



Specific 
Gravity of 
Specimen 

s=:^. 



a. 26 

«. 27 

« 28 
a. 29 

a. 30 

X 31 
cc 32 
X 33 

a 34 

« 35 

a- 36 
a 37 
a 38 

« 39 

a 40 
a 41 



e 


42 


a 


43 


X 


44 


a 


45 


a 


46 


a 


47 


a 


48 


a. 


49 


a 


50 


a 


51 


a 


52 


a 


53 


a 


54 


a 


55 


tt. 


56 


a, 


57 



No. 1. 
No. 1. 
No. 3. 
No. 3. 
No. 4. 
No. 4. 
No. 1. 
No. 1. 
No. 2. 
No. 2. 
No. 3. 
No. 3. 
No. 2. 
No. 2. 
No. 3. 
No. 3. 
No. 4. 
No. 4. 
No. 2. 
No. 2. 
No. 3. 
No. 3. 
No. 1. 
No. 1. 
No. 2. 
No. 2. 
No. 3. 
No. 3. 
No. 4. 
No. 4. 
No. 2. 
No. 2. 



Clyde, 35 years made , 
Clyde, 35 years made , 

Calder 

Calder 

Calder 

Calder 

Gartsherry 

Gartaherry 

Gartsherry 

Gartsherry 

Gartsherry 

Gartsherry 

Summerlie 

Summerlie 



Cold 
Cold 
Hot 
Hot 
Hot 
Hot 
Hot 
Hot 
Hot 
Hot 
Hot 
Hot 
Hot 
Hot 

Monkland I Hot 

Monkland j Hot 

Monkland Hot 

Monkland Hot 

Muirkirk Hot 

Mnirkirk Hot 

Muirkirk Hot 

Muirkirk Hot 

Shotts Hot 

Shotts Hot 

Shotts Hot 

Shotts I Hot 

Shotts I Hot 

Shotts Hot 

Shotts Hot 

Shotts * Hot 

Muirkirk Cold 

Muirkirk i Cold 



Mottled 
IMottled 
Bright gray 
Bright gray 
Silvery 
Silvery 
Briglit pray 
Bright gray 
Bright gray 
Bright gray 
Bright gray 
Bright gray 
Bright gray 
Bright gray 
Dull gray 
Dull gray 
Mottled 
Mottled 
Micaceous 
Micaceous 
Dull gray 
Dull gray 
Dull gray 
Dull gray 
Dull gray 
Dull gray 
Bright gray 
Bright gray 
Silvery 
Silvery 
Dark gray 
Dark gray 



Green 
Green 
Green 
Green 
Green 
Green 
Green 
Green 
Green 
Green 
Green 
Green 
Green 
Green 
Green 
Green 
Green 
Green 
Green 
Green 
Green 
Green 
Green 
Green 
Green 
Green 
Green 
Green 
Green 
Green 
Green 
Green 



7-140 
7131 
7064 
7055 
7-527 
7-518 
7-001 
6-990 
7-115 
7106 
7074 
7-065 
7-146 
7-156 
7-115 
7-124 
7-285 
7-294 
6-971 
6-980 
6-829 
6-838 
7-099 
7-109 
7-143 
7-152 
7-183 
7-173 
7-158 
7-149 
7-076 
7-067 



Box «. No. 1. Class No. 5. 



a, 58 


No. 2. Doulais. Common bar ... 




Fihrous Green 


7-587 



Box «. No. 1. Class No. 6. 



v 59 


No. 1. 
No. 1. 


Calder 


Hot 


Dark gray 
Mottled 


Green 
Chilled 


7.027 
7-079 


J 


a. 6 


Calder 


Hot 



ON THE ACTION OF AIR AND WATKK UPON IRON. 277 

Scotch Cast Irons. 





6. 


7. 


8. 


9. 


10. 


11. 


12. 


13. 








Weight of 


Total loss 


loss of 


Loss of 


"^^■6 






Dimensions of 


Weight of 


Specimen 


by 


Weight 


Weight 


^ aJ 11 


Character of 




Specimen. 


Specimen 
in Grains. 


after 387 

days' 
exposure. 


Corrosion 
in 3K7 days. 


per square 
inch of 
Surface. 


referred to 

Standard 

Bar. 


m 


Corrosion- 




in. in. in. 


















5x5x1 


44309 


43961 


348 


4-97 


-469 


0- 


Uniform P. 




5 X 5 X -25 


11885 


11514 


371 


6-74 


-636 


0- 


Uniform P. 




5x5x1 


43624 


43276 


348 


4-97 


-469 


0- 


Local. 




5 X 5 X -25 


11885 


11527 


358 


6-51 


-614 


0^ 


Local. 




5x5x1 


43519 


43085 


434 


6-20 


-585 


0- 


Tubercular. 




5 X 5 X -25 


12043 


11671 


372 


6-76 


-636 


0- 


Tubercular. 




5x5x1 


43734 


43334 


400 


5-71 


•539 


0^ 


Uniform P. 




5 X 5 X -25 


11918 


11404 


514 


9-34 


•881 


0- 


Uniform. 




5X5X1 


43890 


43558 


332 


4-74 


-447 


0- 


Uniform. 




5 X 5 X -25 


11735 


11275 


460 


8-36 


•789 


0- 


Uniform. 




5x5X1 


42513 


42172 


341 


4-87 


•459 


0- 


Local. 




5 X 5 X -25 


11732 


11265 


467 


8-49 


•801 


0- 


Local pitted. 




5 X 5 X -25 


11830 


11238 


592 


10-76 


1-015 


0- 


Uniform. 




5X5X1 


43920 


43700 


220 


314 


•296 


0- 


Uniform. 




5 X 5 X -25 


11789 


11147 


642 


11-67 


1-101 


0- 


Local. 




5X5X1 


42795 


42574 


221 


3-16 


-298 


0- 


Local. 




5 X 5 X -25 


12183 


11701 


482 


8-76 


-826 


0- 


Tubercular. 




5X5X1 


44600 


44269 


331 


4-73 


•446 


0^ 


Tubercular. 




5 X 5 X -25 


11534 


10916 


618 


11-23 


1-059 


0^ 


Uniform P. 




5X5X1 


43388 


43184 


204 


2-91 


-275 


0^ 


Uniform P. 




5 X 5 X -25 


11894 


11343 


551 


10-02 


•945 


0- 


Tubercular. 




5X5X1 


42786 


42575 


211 


3-01 


•284 


0- 


Tubercular. 




5 X 5 X -25 


11892 


11449 


443 


805 


•759 


0- 


Uniform P. 




5X5X1 


43447 


43061 


386 


5-51 


-520 


0^ 


Uniform P. 




5 X 5 X -25 


12267 


11754 


515 


9-36 


•883 


0- 


Uniform P. 




5X5X1 


44139 


43911 


228 


3-25 


•307 


0- 


Uniform. 




5X5X1 


44155 


43781 


374 


5-34 


•504 


0- 


Local pitted. 




5 X 5 X -25 


11857 


11381 


476 


8-65 


•816 


0- 


Local. 




5X5X1 


4,3691 


43429 


262 


3-74 


•353 


13^0 


Tubercular. 




5 X 5 X -25 


11901 


11380 


521 


9-47 


•893 


2-0 


Tubercular. 




5x5x1 


43225 


43026 


199 


2-84 


•267 


0- 


Uniform P. 




5 X 5 X -25 


11672 


11025 


647 


11-76 


1109 


0- 


Uniform P. 



The Standard Bar of Wrought Iron. 



5 X 5 X -875 


24440 


23972 


468 


10-636 


1-000 


0- 


Uniformly 
striated . 



Scotch Cast Iron. Chilled. 



5x5x1 42470 
5x5x1 43570 



42042 
43034 



428 
536 



611 
7-65 



-576 
•722 



Uniform P. 
Tubercular. 



278 


RKPORT 


—1840. 

Box a. No. 1. 


Class 


No. 7| 


1, 


2. 


3. 


4. 


5. 


No. of 

Experiment 

and mark 

of Specimen. 


Commercial Character of Iron. 


Hot or 
Cold 

Blast. 


External 

Character of 

Fracture. 


How Cast. 


Specific 
Gravity of 
Specimen 
Ws 


« 61 
« 62 




Hot 
Hot 


Mottled 
Silvery 


Green 7017 
Chilled 7-129 










Box a. No. 1 


Class No. 8. 


«. 63 

a 64 




Cold 
Cold 


Mottled 
Silvery 


Green 

Chilled 


7-268 
7-603 


No 2 Apedale 










Box «. No. 1 


Class No. 9. 


« 65 
a. 66 




Cold 
Cold 


Dull gray 
Mottled 


Green 
Chilled 


7-141 

7-308 










Box 


«. No. 1. 


Class No. 10, 



« 67 

a, 68 
a 69 



Hardest procurable. Old fire-bars 
U No. 1. Calder 

\ -f j No. 2. Pentwyn 

f 4 No. 2. Arigna 

\ -|- § No. 2. Pentwyn 



Hot 
Hot 
Cold 
Hot 



Silv. Crystals. 
Close dull 1 

gray J 

Close dull 1 

gray J 



Chilled 
Green 

Green 



7-624 
6-978 

7-050 



Box a. No. 1. Class No. 11. Cast Irons of Messrs. 



70 
71 
72 
73 
74 
75 
76 



No. 2. Carron 

No. 2. Caedtallon 
No. 2. Carron .... 
No. 2. Caedtallon 
No. 1. Buffery.... 
No. 1. Milton .... 
No. 1. Elsecar.... 



Cold 
Hot 
Hot 
Cold 
Hot 
Hot 
Cold 



Dark gray 


Green 


Dull gray 


Green 


Bright gray 


Green 


Dull gray 


Green 


Dull gray 


Green 


Dark gray 


Green 


Bright gray. 


Green 



7-107 
7-030 
7-081 
7-020 
7-063 
7-073 
7-097 



Box «. No. 1. Class No. 12. Gray Cast Iron. 



a 77 



fiNo. 1. Calder. i No. 2.|Lj^ f 
1^ Pentwyn. \ Scrap J L 



Close bright 
gray 



Green 



7138 



ON THE ACTJON OF AIR AND WATER UPON IRON. 279 

Welsh Cast Iron. Chilled. 





6. 1 7. 


8. 


9. 


10. 


11. 


12. 


13. 




Dimensions i Weight of 

of 1 Specimen 

Specimen. in Grains. 


Weight of 
Specimen 

after 
3S7 days' 
exposure. 


Total loss 

by 
Corrosion 

in 
38" days. 


Loss of 

Weightpor 

square inch 

of 

Surface. 


Loss of 

Weight 

referred to 

Standard 

Bar. 


Ill 
1^1 


Character 

of 
Corrosion. 




In. in. in. ! 

5x5x1 41990 
5x5x1 43830 


41538 
43251 


452 
579 


6-45 

8-27 


•608 
•780 


0- 
0- 


Uniform P. 
Tubercular. 




Staffordshire Cast Iron. 


Chilled. 












5x5x1 

5x5x1 


42870 
44290 


42395 

43868 


475 
422 


6-78 
6-03 


•640 
•569 


0- 
0- 


Uniform. 
Tubercular. 




[rish Cast Iron. Chilled. 














5x5x1 

5x5x1 


42790 
42757 


42296 

42288 


494 
469 


7-06 
6-70 


•666 
•632 


0- 
0- 


Uniform P. 
Tubercular. 



Mixed Cast Irons. 



5x5x1 


43259 


42875 


384 


5.48 


•517 


5^0 


Tubercular. 


5x5x1 


42522 


41970 


552 


7^88 


•734 


0^ 


Tubercular. 


5x5x5 


41589 


41140 


449 


641 


•605 


0^ 


Tubercular. 



Fairbairn's and Hodgkinson's Experiments on Cohesion. 



3 X 1-25 x 1-25 


9132 


8926 


206 


ir40 


1-075 


0- 


Uniform^. 


4x1 Xl 


7504 


7332 


172 


9-55 


■901 


0^ 


Uniform. 


4x1 Xl 


7231 


7061 


170 


9-44 


•891 


0^ 


Uniform P. 


4x1 Xl 


7877 


7733 


144 


8-00 


•75o 


0^ 


Uniform P. 


4x1 Xl 


7454 


7301 


153 


8-50 


•802 


0^ 


Uniform P. 


4x1 Xl 


7960 


7826 


134 


7^44 


•702 


0^ 


Uniform. 


4x1 Xl 


7370 


7215 


155 


8-61 


•812 


0^ 


Uniform P. 



Skin removed by Planing. 



5 X 5 X -75 34130 33595 535 823 ^776 0^ Uniform. 



280 



REPORT 1840. 

Box «. No. 1. Class No. 13. Gray Cast Iron. 



1. 


2. 


3. 


4. 


5. 


No. of 
Experiment 

and mark 
of Specimen. 


Commercial Character of Iron. 


Hot or 
Cold 
Blast. 


External 

Character of 

Fracture. 


How Cast. 


Specific 
Gravity of 
Specimen 


« 78 

a 79 

OL 80 

« 81 

a. 82 


rj No. 1. Calder 


Hot 
Hot 
Hot 
Hot 
Hot 
Hot 
Hot 
Hot 
Hot 


Close bright "I 

gray J 
Close bright \ 

gray J 
Close bright" 

gray 
Close bright 1 

gray J 
Close bright \ 

gray J 


Green 
Green 
Green 
Green 
Green 


7-108 
7-168 
7-168 
7-168 
7-168 


\ -T \ No. 2. Pentwyn -)- 5 Scrap 
[A No. 1. Calder 


\ -\-\ No. 2. Pentwyn -f i Scrap 
|i No. 1. Calder 


\ -\-\ No. 2. Pentwyn + \ Scrap 
rj No. 1. Calder 


t + i No. 2. Pentwyn + \ Scrap 
f i No. 1. Calder 


\ 4- ^ No. 2. Pentwyn + \ Scrap 


Hot 



Supplementary Table. 



No. of 
Experiment 

and mark 
of Specimen. 


Protective Paint or Varnish. 


State of Covering after 387 days' exposure. 


« 78 

a. 78 

« 79 
«. 79 
«. 80 
e 80 

a. 81 

« 81 
« 82 
« 82 


Caoutchouc varnish 


Rusted off in spots and partly removed... 
Rusted in spots; oil partially removed ... 










Coated thinly with extremely hard rust ... 




3 parts wax -)- 2 parts tallow. ... 




Coating still visible, with some lustre 
















ON THE ACTION OF AIR AND WATER UPON IRON. 281 

protected by Paints or Varnishes. 





6. 


7. 


8. 


9. 


10. 


11. 


12. 


13. 




Dimensions 

of 
Specimen. 


Weight of 
Specimen 
in Grains. 


Weight of 
Specimen 

after 
387 days' 
exposure. 


Total loss 

Corrosion 

in 
387 days. 


Loss of 

Weight per 

square inch 

of 

Surface. 


Loss of 

Weight 

referred to 

Standard 

Bar. 




Character 

of 
Corrosion. 




in. in, in. 


















5x5x1 


42580 


42143 


437 


6-24 


•589 


0- 







5x5x1 


42664 


42490 


174 


2-48 


•234 


0^ 






5x5x1 


41958 


41691 


267 


3-81 


•359 


0- 


!•• 




5x5x1 


42721 


42466 


255 


3-64 


•343 


0- 






5x5x1 


42293 


41950 


343 


4-90 


•462 


0- 





Box a. No. 1. Class No. 13. 



Condition of Surface of Specimen after 387 days' exposure. 



Corroded in spots, with blotches of plumbago 

Corroded in spots; no plumbago formed 

Skin of the iron unbroken 

Skin of the iron unbroken 

Skin not broken into pits; no plumbago 

Skin unbroken ; no plumbago 

Skin sound, only corroded at the edges 

Corroded in spots, with tubercles of oxide .... 

Corroded at edges and in pits; plumbago 

Corroded at edges and in pits; plumbago 



Order of 

Protective 

Power. 



9 
10 
2 
1 
6 
5 
3 
4 
7 



282 



REPORT — 1840. 



Table 

Box /3. No. 2. containing Specimens of Cast and 

Sunk and moored in the foul Sea Water, close to the mouth of the Great Kings- 
flood-tide. Bottom soft putrid mud. Temperature of water from 4C 
o'clock P.M. on the 3rd of August, 1838. Weighed and landed on the 26th 
the 13th of January, and now immersed. Specific gravity of water at 

Box/3. No. 2. Class No. 1. 



1. 


2. 


3. 


4. 


5. 


No. of 

Experiment 

and mark 

of Specimen. 


Commercial Character of Iron. 


Hot or 
Cold 
Blast. 


External 

Character of 

.Fracture. 


How Cast. 


Specific 
Gravity of 
Specimen 

to 


/3 1 

a 2 


No 1 Calder 


Hot Dark gray 
Hot Mottled 


Green 
Chilled 


7027 
7-079 


No 1 Calder 






1 



Box /3. No. 2. Class No. 2. 





Hot 
Hot 


Mottled 
Silvery 


Green 7-017 
Chilled 7-129 







Box jS. No. 2. Class No. 3. 



H 5 
/3 6 



No. 2. Apedale Cold Mottled 

No. 2. Apedale Cold Silvery 



Green 
Chilled 



7-268 
7-603 



Box (S. No. 2. Class No. 4. 



a 7 
a 8 




Cold 
Cold 


Dull gray 
Mottled 


Green 
Chilled 


7-141 

7-308 









Box /3. No. 2. Class No. 5. 



/3 9 
iS 10 

/3 11 



Hardest procurable. 01dfirebars,&c. 
k No. 1. Calder 

+ i No. 2. Pentwyn 

i No. 2. Arigna 

-|-^No.2. Pentwyn 



{* 



Hot \ 
Hot J 
Coldl 
Hot ; 



Silvery crystals 
Close dull gray 

Close dull gray 



Chilled 
Green 

Green 



7-624 
6-978 

7-050 



ON THE ACTION OF AIR AND WATER UPON IRON. 



283 



No. II. 

Wrought Iron immersed in Foul Sea Water. 

town Main Sewer. Depth of water two feet at ebb, and from eight to twelve at 
Fahr. to 58° Fahr. Receives fresh water during heavy rains. Sunk at 4 
of August, 1839, at the same hour ; thus immersed 387 days. Sunk again on 
Mouth of Sewer = 1027-70 filtered. 

Scotch Cast Irons. 





6. 


7. 


8. 


9. 


10. 


11. 


12. 


13. 




Dimensions of 
Specimen. 


Weight of 
Specimen 
in Grains. 


Weiglit of 
Specimen 

after 
387 days' 
exposure. 


Total loss 
Corrosion 
387 days. 


Loss of 
Weiglit 

per square 
inch 

of Surface. 


Loss of 

Weight 

referred to 

Standard 

Bar. 


Ill 


Character of 
Corrosion. 




in. in. in. 
5X5X1 
5x5x1 


42895 
43636 


42674 
43046 


221 
590 


315 

8-42 


•297 
•794 


0- 
0- 


Uniform P. 
Tubercular. 



Welsh Cast Iron. 



5x5x1 
5x5x1 



42309 
43689 



42160 
43032 



149 
657 



213 

9^38 



201 

•885 



Uniform P. 
Local. 



Staffordshire Iron. 



5x5x1 42291 
5x5x1 43749 


42237 
43596 


54 
153 


0-77 
219 


•073 
•207 


0- 
0- 


Uniform. 
Local. 



Irish Cast Iron. 



5x5x1 
5x5x1 


42107 
43155 


41985 
42357 


122 

798 


1-74 
11-40 


•164 
1075 


0^ 
0- 


Uniform P. 
Local. 



Mixed or alloyed Cast Irons. 



5x5x1 
5x5x1 

'5x5x1 



43193 


43051 


142 


2^03 


•192 


20 


42232 


42051 


181 


2^58 


•243 


0^ 


42215 


42029 


186 


2^65 


•250 


0- 



Tubercular, 
Local. 

Local. 



284 



REPORT — 1840. 

Box /3. No. 2. Class No. 6. 



1. 


2. 


3. 


4. 


5. 




No. of 

Experiment 

and mark 

of Specimen. 


Commercial Character of Iron. 


Hot or 
Cold 

Blast. 


External 

Character of 

Fracture. 


How Cast. 


Specific 
Gravity of 
Specimen 




/3 12 






Fibrous. 


Green 


7-587 











Box /3. No. 2. Class No. 7. 



,„ fi No. 1. Calder + i No. 2.1 „ 
'^ '"* h Pentwyn + 1 Scrap / "°' 



Close bright gray 



Green 



7-138 



Box /3. No. 2. Class No. 8. 



/3 14 

^ 15 

/3 16 

/3 17 

/3 18 



No. 1. Calder + i No. 2." 

Pentwyn + ^ Scrap 

No. 1. Calder + i No. 2,' 

Pentwyn -|- I Scrap 

No. 1. Calder + a No. 2. 

Pentwyn + ^ Scrap 

No. 1. Calder + i No. 2. ' 

Pentwyn + i Scrap 

No. 1. Calder + a No. 2. " 
Pentwyn + ^ Scrap 



Hot 
Hot 
Hot 
Hot 
Hot 



Close bright gray 
Close bright gray 
Close bright gray 
Close bright gray 
Close bright gray 



Green 


7168 


Green 


7-168 


Green 


7-168 


Green 


7-168 


Green 


7-168 



Supplementary Table. 



No. of 

Experiment 

and mark 

of Specimen. 


Protective Paint or Varnish. 


State of Covering after 387 days* exposure. 




H 14 
li 14 
/3 15 
/3 15 
^ 16 
/3 16 
/J 17 
/3 17 
/3 18 
li 18 
























Scarcely any remaining 


Three parts wax + two parts tallow 










Not visible 







ON THE ACTION OF AIR AND WATER UPON IRON. 285 

Standard Bar Wrought Iron. 



Dimensions of 
Specimen. 



in. in. in. 

4-873 X 3 X -875 



1. 



Weight of 
Specimen 
in Grains. 



28977 



Weight of 
Specimen 
after 387 



23436 



Total loss 

Corrosion 

in 
387 days. 



541 



10. 



Loss of 
Weight 
per square 
inch of 
Surface. 



12-57 



Loss of 

weight 

referred to 

Standard 

Bar. 



1-186 



12. 



■Sfeg 



Gray Cast Iron. Skin removed by planing. 



5 X 5 X -75 



34131 33150 981 13-55 



1-278 



Gray Cast Iron, protected by Paints or Varnishes. 



Box /3. No. 2. Class No. 8. 



13. 



Character of 
Corrosion. 



Uniform str. 



0- Uniform. 



5x5x1 


43050 


42071 


979 


13-98 


1-319 


0- 




5x5x1 


42940 


42295 


645 


7-22 


-681 


0- 




5x5x1 


41668 


41257 


411 


5-87 


-554 


0- 




5x5x1 


41568 


41288 


280 


4-00 


•377 


0- 




5x5x1 


42480 


42166 


314 


4-48 


-623 


0- 





Condition of Surface of Specimen after 387 days' exposure. 



Skin unbroken, rusty 

Skin unbroken, rusty 

Skin sound, soft in spots 

Skin sound, hard rust 

Skin sound, hard rust 

Skin sound, hard rust in spots .... 
Skin sound, and blue rusty in spots 

Skin sound, hard rust 

Skin sound, hard rust 

Skin sound, hard rust 



Order of 

Protective 

Power. 



9 
10 
8 
7 
6 
5 
2 
1 
3 
4 



286 



REPORT — 1840. 



Table 

Box 7. No. 3. containing Specimens of Cast and Wrought 

110° to 



Sunk in the Plate-iron Hot Water Cistern of the Dublin and Kingstown 
24 inches. Heated by circulation of water from a boiler. Temperature 
Taken out and removed in consequence of alterations in the arrangements 
immersed 117 days. Specific gravity of water at 60° Fahr. = 1027-80. 

Box y. No. 3. Class No. 1. 



1. 


2. 


3. 


4. 


5. 


No."'' 
Experiment 

and mark 
of Specimen. 


Commercial Character of Iron. 


Hot or 
Cold 
Blast. 


External 

Character of 

Fracture. 


How Cast. 


Specific 
Gravity of 
Specimen 


y 1 

y 2 


No. 1. Calder 


Hot 

Hot 


Dark gray 
Mottled 


Green 
Chilled 


7-070 


No. 1. Calder 





Box y. No. 3. Class No. 2 



y .3 
y 4 



No. 2. Pentwyn 
No. 2. Pentwyn 



Hot 
Hot 



Mottled 
Silvery 



Green 

Chilled 



7-017 
7-12'J 



Box y. No. 3. Class No. 3 



y 5 
y 6 



No. 2. Apedale 
No. 2. Apedale 



Cold 
Cold 



Mottled 
Silvery 



Green 
Chilled 



7-268 
7-603 



Box y. No. 3. Class No. 4 



y 7 
y 8 



No. 3. Arigna 
No. 3. Arigna 



Cold 
Cold 



Dull gray Green 
Mottled Chilled 



7-141 

7-308 



Box y. No. 3. Class No. £ 



y 9 
y 10 
y 11 



r Hardest procurable. Oldfire- 
\ bars, &c 

\i Calder. No. 1 

1 + i Pentwyn. No. 2. ... 

J^No. 2. Arigna 

\ -\- i No. 2. Pentwyn ... 







Hot 


1 


Hot 


Cold 


} 


Hot 



Silvery crystals 
Close dull gray 
Close dull gray 



Chilled 

Green 

Green 



7-624 
6-978 
7-050 



ON THE ACTION OF AIR AND WATER UPON IRON. 



287 



No. III. 

Iron immersed in clear Sea Water at Temperature from 
125° Fahr. 

Railway Company's Baths at Salt Hill, near Kingstown. Depth of water 
nearly constant at 115° Fahr. Sunk on the 6th of August, 1838, at 4 o'clock p.m. 
of the Baths, on the 1st of December, 1838, at same hour, having thus been 



Scotch Cast Iron. 





6. 


7. 


8. 


9. 


10. 


11. 


12, 


13. 




Dimensions of 
Specimen. 


Weight of 
Specimen 
in Grains. 


Weight of 
Specimen 

after 
117 days' 
exposure. 


Totalloss 

by 
Corrosion 

in 
117 days. 


Loss of 

Weight per 

square inch 

of 

Surface. 


Loss of 

Weight 

referred to 

Standard 

Bar. 


^ Si ^ 


Character of 
Corrosion. 




in. in. in. 

5x5x1 
5x5x1 


43167 
44109 


43149 
43939 


18 

170 


0-257 
2-43 


•803 
•759 


0- 
0- 


Uniform. 
Local. 



Welsh Cast Iron. 



5x5x1 
5x5x1 


42320 42239 
43363 43239 


81 
124 


115 

1^77 


•359 
•553 


0^ 
0- 


Uniform. 
Local. 



Staffordshire Cast Iron. 



5x5x1 
5x5x1 


43805 43735 
43710 43562 


70 
148 


100 
2^10 


•312 
•656 


0^ 
0- 


Local. 
Local. 



Irish Cast Iron. 



5x5x1 
5x5x1 


41805 
43651 


41745 
43465 


60 
186 


0^85 
2-65 


•265 

•827 


0- 
0^ 


Uniform. 
Local. 



Mixed or alloyed Cast Irons. 





5x5x1 


43326 


43315 


11 


0^16 


•050 


0^ 


Tubercular. 




5x5x1 


42337 


42241 


96 


137 


•427 


0^ 


Local. 




5x5x1 


41433 


41341 


92 


131 


•409 


0- 


Local. 



288 


REPORT — 1840. 

Box y. No. 3. Class No. 6. 


1. 


2. 


3. 


4. 


5. 


No. of 
Experiment 
and mark of 
Specimen. 


Commercial Character of Iron. 


Hot or 
Cold 
Blast. 


External 

Character of 

Fracture. 


How Cast. 


Specific 
Gravity of 
Specimen 


y 12 






Fibrous 


Green 


7-587 






Box y. No. 3. Class No. 7- Gray Cast Iron. 


y 13 


r i No. 1. Calder + i No. 2. 1 
\ Pentwyn -j- ^ Scrap J 


Hot 


Closebrightgray 


Green 


7-138 


Box y. No. 3. Class No. 8. Gray Cast Iron, 



y 14 
y 15 
y 16 

y 17 

y 18 


Ji No. 1. Calder + i No. 2.1 

L Pentwyn 4- i Scrap J 

JiNo. 1. Calder + ^ No. 2. 1 

\ Pentwyn -j- i Scrap J 

/J No. 1, Calder + i No. 2.1 


Hot 
Hot 
Hot 
Hot 
Hot 


Closebrightgray 
Closebrightgray 
Close bright gray 
Closebrightgray 
Closebrightgray 


Green 
Green 
Green 
Green 
Green 


7-1C8 
7-168 
7-168 
7-168 

7-1G8 


fiNo. 1. Calder + i No. 2.1 

\ Pentwyn -j- ^ Scrap J 

/JNo. 1. Calder + ^ No. 2.1 
\ Pentwyn + I Scrap J 



Supplementary Table y. 



No. of 
Experiment 
and mark of 
Specimen. 


Protective Paint or Varnish. 


State of Covering after 117 days* exposure. 


yU 
yU 
yX5 
y 15 
yl6 
y 16 
yl7 
yl7 

y\S 

y 18 






















Swedish tar 




3 parts wax and 2 parts tallow ... 






Turpen tine varnish 






Notvisihlp 





ON THE ACTION OF AIR AND WATER UPON IRON. 289 

Standard bar of Wrought Iron. 





6. 


7. 


8. 


9. 


10. 


11. 


12. 


13. 




Dimensions of 
Specimen. 


Weight of 
Specimen 
in Grains. 


Weight of 
Specimen 

after 
117 days' 
exposure. 


Total loss 

Corrosion 

in 
117 days. 


Loss of 
Weight per 
square inch 
of Surface. 


Loss of 

Weight 

referred to 

Standard 

Bar. 




Character of 
Corrosion. 




in. in. in. 

5 X 3 X -875 


24464 


24274 


190 


4-318 


1-35 


0- 


Unif. striated. 



Skin removed by planing. 



5 X 5 X -75 


34024 


33750 


274 


4-21 


1-31 


0- 


Uniform. 



protected by Paints or Varnishes. 



5x5x1 


42618 


42594 


24 


0-34 


•106 


0- 


» » 


5x5x1 


42673 


42644 


29 


0-41 


•127 


0- 


»> » 


5x5x1 


42457 


42399 


58 


0-83 


•259 


0- 


» » 


5x5x1 


42075 


42007 


68 


0-97 


•303 


0^ 


» » 


5x5x1 


42094 


42004 


90 


1-28 


•368 


0^ 


„ „ 



Box No. 3. Class No. 8. 



Condition of surface of Specimen after 117 days' exposure. 



Order of 

Protective 

Power. 



Uniform rusting. Surface hard 

Rusted in spots. Hard. No plumbago 

Skin sound. Minute cavities 

Skin sound. Hard rust uniformly 

Skin sound. Hard uniform rust 

Skin sound. Uniform rust 

Skin still fresh in parts. Rusted in pits 
Rusted in spots. Plumbago in spots .... 

Plumbago in various spots 

Pitted in places. Hard rust uniformly , 



1 
4 
2 

3 

5 
6 
8 
7 
9 
10 



1840. 



290 


report- 


-1840. 








Table 




Box 8. No. 4. containing Specimens of Cast and Wrought 


Sunk and moored in the mid-stream of the river LifFey, at Dublin, opposite 
and from fifteen to twenty feet at flood-tide. The water fresh at ebb-tide, 
from 36° Fahr. to 01° Fahr. Sunk on the Gth of August, 1838, at five 
hour, having been immersed for 383 days. Again sunk in same place at 
water =1002-27. 




Box 8. No. 4. Class No. 1. 


1. 


2. 


3. 


4. 


5. 


No. of 
Experiment 
and mark 
of Specimen. 


Commercial Character of Iron. 


Hot or 
Cold 
Blast. 


External 

Character of 

Fracture. 


How Cast. 


Specific 
Gravity of 
Specimen 


S 1 
S 2 


No. 1. Calder 


Hot 
Hot 


Dark gray 
Mottled 


Green 
Chilled 


7-027 
7-07!» 


No. 1. Calder 










Box 8. No. 4 


. Class No. 2, 



I 3 
i 4 



No. 2. Pcntwyn 

No. 2. Pentwyn 

No. 2. Apedale. 

No. 2. Apedale. 

No. 3. Arigna... 

No. 3. Arigna... 



Hot 
Hot 



Mottled 
Silvery 



Green 
Chilled 



7-017 
7-129 



Box 8. No. 4. Class No. 3. 



s 5 
S 6 



Cold 
Cold 



Mottled 
Silvery 



Green 
Chilled 



7-2(;s 

7-603 



Box 8. No. 4. Class No. 4. 



S 7 



Cold 
Cold 



Dull gray 
Mottled 



Green 
Chilled 



7-111 

7-308 



Box 8. No. 4. Class No. sJJ 



S 9 
S 10 

I 11 



Hardest procurable. Old firebars, &c. 

ii Calder No. 1 

\ -f i Pentwyn No. 2 

[^ No. 2. Arigna 

\ -\- i No. 2. Pentwyn 



Hot 1 
Hot / 
Coldl 
Hot J 



Silvery crystals 
Close dull gray 

Close dull gray 



Chilled 
Green 

Green 



7-624 
6-978 

7-050 



ON THE ACTION OF AIR AND WATER UPON IRON. 



291 



No. IV. 



Iron, immersed in Foul River Water, within the tidal limits. 

the junction of the Poddle River therewith. Depth of water four feet at ebb, 
and very brackish at flood. Bottom soft putrid mud. Temperature of water 
o'clock P.M. Weighed and landed again on the 24th of August, 1839, at same 
one o'clock p.m., January 13th, 1840, and now immersed. Specific gravity of 



Scotch Cast Iron. 



10. 



11. 



12. 



13. 



Dimensions of 
Specimen. 



Weight of 
Specimen 
in Grains. 



I 
Weight of , Total loss 
Specimen 

after 
383 days' 
exposure. 383 days. 



Loss of 
Weight per 
square 
inch of 
Surface. 



Loss of 

Weight 

referred to 

Standard 

Bar. 



.£Prt o 



Character of 
Corrosion. 



5x5x1 
5x5x1 



41449 
43295 



41145 

42885 



304 
410 



4-34 
5-85 



•417 
•562 



Local P. 
Tubercular. 



Welsh Cast Iron. 


5x5x1 42462 
5x5x1 43333 


42181 
42903 


281 
430 


4-01 
6^14 


•378 
•590 


0- 
0- 


Local P. 
Tubercular. 


Staffordshire Cast Iron. 


5x5x1 

5x5x1 


44976 
43760 


44857 
43478 


119 

282 


1-70 
4-03 


•163 
•373 


0^ 
0^ 


Tubercular. 
Tubercular. 


Irish Cast Iron. 












5x5x1 
5x5x1 


40741 
42675 


40305 
42241 


436 
434 


6^23 
6-20 


•599 
•598 


0^ 
0^ 


Local P. 
Tubercular. 


Mixed or alloyed Cast Irons. 



5x5x1 
5x5x1 

5x5x1 



44799 


44473 


326 


4^65 


•447 


0- 


42454 


42147 


307 


4^38 


•421 


0^ 


42318 


41981 


337 


4-81 


•462 


0^ 



Tubercular. 
Tubercular. 

Tiibercular. 



u 2 



292 



REPORT 1840. 

Box 8. No. 4. Class No. 6. 



1. 


2. 


3. 4. 


5. 




No. of 

Experiment 

and mark 

of Specimen. 


Commercial Character of Iron. 


Hot or 
Cold 
Blast. 


External 

Character of 

Fracture. 


How Cast. 


Specific 
Gravity of 
Specimen 

S-^^». 

w 




J 12 






Fibrous 


- 


7-5S7 











Box S. No. 4. Class No, /. 



i 13 


Ji No. 1. Calder + i No 
\ Pentwyn -f- 3 Scrap ... . 


':} 


Hot Close bright gray 


Green 7-138 








Box 8. No. 4 


. Class No. 8. 



S 14 
S 15 
S 16 
S 17 

S 18 



r i No. 1. Calder + i No. 2. \ 

L Pentwyn + ^ Scrap J 

/i No. 1. Calder + ^ No. 2.1 

\ Pentwyn + ^ Scrap J 

fi No. 1. Calder + i No. 2.1 

L Pentwyn + ^ Scrap J 

/A No. 1. Calder + ^ No. 2.1 

\ Pentwyn -)- ^ Scrap _f 

|i No.U. Calder + i No. 2. 1 
\ Pentwyn + J Scrap J 



Hot 
Hot 
Hot 
Hot 
Hot 



Close brightgray 


Green 


Closebrightgray 


Green 


Close bright gray 


Green 


Closebrightgray 


Green 


Closebrightgray 


Green 



7-168 
7-168 
7-168 
7-168 
7-168 



Supplementary Tablel 





^&1^ 


W-'-S 


S 14 


S 14 


S 15 


S 15 


J 16 


I 16 


S 17 


S 17 


S 18 


S 18 



Protective Paint or Varnish. 



State of Covering after 383 days' exposure. 



Caoutchouc varnish 

Best white-lead paint 

Copal varnish 

Asphaltum varnish 

Mastic varnish 

Swedish tar 

Three parts -wax -\- two parts tallow 

Coal-tar, laid on hot 

Turpentine varnish 

Drying oil 



Varnish not visible 

Paint removed in spots 

Varnish not visible 

Varnish not visible , 

Varnish not visible 

No longer visible 

Gone, or changed into adipoccre 

Still lustrous and black 

Varnish not visible 

Not visible 



ON THB ACTION OP AIR AND WATER UPON IRON. 293 

Standard Bar Wrought Iron. 



7. 



10. 



11. 



12. 



13. 



Dimensions of 
Specimen. 



Weight of 
Specimen 
in Grains. 



Weight of 
Specimen 

aiter 
383 days' 
exposure. 



Total loss 

Corrosion 

in 
383 days. 



Loss of 
Weight per 
square inch 
of Surface, 



Loss of 

Weight 

referred 

to Standard 

Bar. 



•stei 



Character of 
Corrosion. 



in. in. in. 

5 X 3 X -875 24380 24062 318 7-227 -694 0- Unif. striated. 



Gray Cast Iron. Skin removed by planing. 



5 X 5 X -75 34114 33674 440 677 -651 0- Uniform. 



Gray Cast Iron, protected by Paints or Varnishes. 



5x5x1 
5x5x1 

5x5x1 
5x5x1 
5x5x1 



42238 


42008 


230 


3-28 


•315 


0- 


42293 


42124 


169 


2-41 


•231 


0^ 


41865 


41582 


283 


4-04 


•388 


Q- 


42973 


42790 


183 


2-61 


•251 


©• 


42150 


41940 


210 


300 


•289 


0- 



Box 8. No. 4. Class No. 8. 



Condition of Surface of Specimen after 383 days' exposure. 



Corroded in pits with plumbago 

Skin sound. Hard rust in spots 

Sliin uniform. Coat of hard rust 

Skin uniform. Coat of hard rust 

Thick coat of tubercular rust 

Soft in spots, with plumbago 

Skin sound. Blue rust in spots 

Skin sound. Superficial rust in spots 

Skin sound. Hard uniform rust 

Skin sound. Hard uniform rust 



Order of 

Protective 

Power. 



7 
1 
2 
9 
10 
4 
3 
5 
6 



294 



REPORT — 1840, 



Table 

Box e. No. 5. containing Specimens of Cast and Wi'ought 

Sunk in clear, unpolluted water of the river Liffey, above the tidal limits, 
stream, varying with season from three to six feet in depth. Temperature 
on the 4th of August, 1838, at five o'clock p.m. Weighed again, and 
days. Again sunk at one o'clock p.m., January the 13th, 1840, and now 

Box e. No. 5. Class No. 1. 



1. 


2. 


3. 


4. 


5. 


No. of 
Experiment 
and mark of 
Specimen. 


Commercial Character of Iron. 


Hot or 
Cold 
Blast. 


External 

Character of 

fracture. 


How Cast. 


Specific 
Gravity of 
Siiecimen 

S=^^ 

w 


E 1 

I 2 


No. 1. Calder 


Hot 
Hot 


Dark gray 
Mottled 


Green 
Chilled 


7-027 
7-079 


No. 1. Calder 














Box £. No. 5 


. Class No. 2. 


e 3 
.4 




Hot 
Hot 


Mottled 
Silvery 


Green 
Chilled 


7-017 
7-120 







Box e. No. 5. Class No. 3. 



I 5 No. 2. Apcdale. 
£ 6 No. 2. Apedale. 



Cold 
Cold 



Mottled 
Silvery 



Green 
Chilled 



7-2(!S 
7-()03 



Box e. No. 5. Class No. 4 



No. 3. Arigna . 
No. 3. Arigna . 



Cold 
Cold 



Dull gray 
Silvery 



Green 
Chilled 



7-141 

7-308 



Box e. No. 5. Class No. 5 



£ 9 


t 10 


s 11 



Hardestprocurable. Old fire-bars,&c, 

i No. 1. Calder 

-|-§No. 2. Pentwyn 

§ No. 2. Arigna 

+ j No. 2. Pentwyn 



Hot 1 
Hot J 
Coldl 
Hot J 



Silvery crystals 
Close dull gray 

Close dull gray 



Chilled 
Green 

Green 



7-624 
6-978 

7-050 



ON THE ACTION OF AIR AND WATER UPON IKON. 



295 



No. V. 



Iron, immersed in the clear Fresh Water of the river Liffey. 

within the premises of the Royal Military Hospital, Kilmaiuham, in a running 
very variable, from 32° Fahr. to 68° Fahr. Bottom of fine granite sand. Sunk 
landed on the 20th of August, 1839, at same hour. Hence immersed for 381 
immersed. Specific gravity of water = 1001-39. 

Scotch Cast Iron. 



' 


6. 


7. 


8. 


9. 


10. 


11. 


12. 


13. 




Dimensions of 
Specimen. 


Weight of 
Specimen 
in Grains. 


Weight of 
Specimen 

after 
381 days' 
exposure. 


Total loss 

by 
Corrosion 

in 
381 days. 


Loss of 
Weight per 
square inch 
of Surface. 


Loss of 

Weight 

referred to 

Standard 

Bar. 


m 


Character of 
Corrosion. 




in. in. in. 
5x5x1 
5x5x 1 


42994 
43579 


42940 
43493 


54 

86 


0-77 
1-22 


•074 
•116 


0- 
0- 


Uniform. 
Tubercular, 



Welsh Cast Iron. 



5x5x1 
5x5x1 


42562 
43025 


42485 
42923 


77 
102 


MO ^104 
145 -139 


0^ 
40 


Uniform. 
Tubercular. 



Staffordshire Cast Iron. 



5x5x1 
5x5x1 



43534 
44174 



43457 
44095 



77 
79 



110 
113 



•104 
•109 



Tubercular. 
Tubercular. 



Irish Cast Iron. 



5x5x1 

5x5x1 



43099 
43963 



43024 
43835 



Mixed or alloyed Cast Irons. 



75 
128 



1-07 
182 



•103 
•175 



Uniform. 
Tubercular. 



5x5x1 


44204 


44125 


79 


M3 


•109 


0- 


Tubercular. 


5x5x1 


43638 


43581 


57 


0-81 


•078 


0^ 


Tubercular. 


5x5x1 


43060 


42975 


85 


121 


•116 


0^ 


Tubercular. 



296 



REPORT — 1840. 

Box s. No. 5. Class No. 6. 



o S So 



. 12 



13 



Commercial Character of Iron. 



No. 2. Doulais. Common bar 



Hot or 
Cold 
Blast. 



External 

Character of 

Fracture. 



Fibrous 



4. 



Specific 
Gravity of 
Specimen 

s=— — • 



7-587 



Box £. No. 5. Class No. 7« Gray Cast Iron. 



fiNo 

l +i 



No. 1. Calder \ 

No. 2. Pentwyn+^ Scrap J 



Hot 



Closebright gray 



Green 



7-138 



Box e. No. 5. Class No. 8. Gray Cast Iron 



14 



15 



16 



17 



18 



{* 
{ 



No. 1. Calder + i No. 2. 1 

Pentwyn -|- ^ Scrap J 

No. 1. Calder + a No. 2. 1 

Pentwyn -(- i Scrap J" 

No. 1. Calder -j- i No. 2.1 
Pentwyn + ^ Scrap J 

i No. 1. Calder + i No. 2. 1 
Pentwyn + I Scrap J 

i No. 1. Calder -|- i No. 2. 1 
Pentwyn + ^ Scrap J 



Hot 
Hot 
Hot 
Hot 
Hot 



Close bright gray 
Close bright gray 
Close bright gray 
Close bright gray 
Close bright gray 



Green 
Green 
Green 
Green 
Green 



7-168 
7-1C8 
7168 
7-168 
7-168 



Supplementary Table. Box 4 



°..gss 



Protective Paint or Varnish. 



State of Covering after 381 days' exposure. 



14 
14 
15 
15 
16 
16 
17 
17 
18 
18 



Caoutchouc varnish 

Best white-lead paint 

Copal varnish 

Asphaltum varnish 

Mastic varnish 

Swedish tar 

3 parts wax + 2 parts tallow 

Coal-tar, laid on hot 

Turpentine varnish , 

Drying oil 



Varnish not visible 

Paint visible ; oil partly gone ^ 

Varnish not tisible 

Varnish scarcely visible 

Varnish not visible 

Scarcely visible 

Gone in spots. Changed to adipocere . 

Still black and lustrous 

Not visible 

Not visible 



ON THE ACTION OF AIR AND WATER UPON IRON. 297 

Standard Bar of Wrought Iron. 



6. 


7. 


8. 


9. 


10. 


11. 


12. 


13. 


Dimensions of 
Specimen. 


Weight of 
Specimen 
in Grains. 


Weight of 
Specimen 

after 
381 days' 
exposure. 


Total loss 

by 
Corrosion 

in 
381 days. 


Loss of 
W^eightper 
square inch 
of Surface. 


Loss of 

Weight 

referred to 

Standard 

Bar. 


o ^ 


Character of 
Corrosion. 


in. in. in. 

5-1375 x3x -875 


24484 


24426 


58 


1-287 


•124 


0- 


Unif. striated. 



Skin removed by planing. 



5 X 5 X -875 


34088 


33922 


166 


2-55 


-245 


0- 


Uniform. 



protected by Paints or Varnishes. 



5x5x1 
5x5x1 

5x5x1 
5x5x1 
5x5x1 



43064 


43015 


49 


0-70 


•067 


0- 


42162 


42139 


23 


0-33 


•031 


0- 


42107 


42052 


55 


0-78 


•075 


0^ 


44277 


44260 


17 


0-24 


-023 


0^ 


42015 


41989 


26 


0-37 


-035 


0^ 



No. 5. Class No. 8. 



Condition of Surface of Specimen after 381 days' exposure. 



Order of 

Protective 

Power. 



Rust in spots. Minute cavities 

Uniform coat of soft rust 

Skin sound. Blue rust in spots 
Skin sound. Rusty in spots .... 
Skin unbroken. Uniform rust , 
Skin unbroken. Uniform rust , 
Skin sound. Rusty in spots ... 

Scarcely any visible rust 

Hard coat of skin. Buff rust ., 
Hard coat of skin. Buff rust . 



7 
8 
4 
3 
10 
9 
2 
1 
5 
6 



298 



REPORT — 1840. 



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I. Cold, chill 
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er No. 1. + 
na No. 2. 4- 


1 
a: 

1 

b 
5 


c 
13 

«3 
C 


Irons protect 
les, as referr 
ntary Tables 






alder 
alder 
entw 
entw 
peda 
peda 
rigna 
rignt 
arde 
Cald 
Arig 








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'^ 







ON THE ACTION OF AIR AND WATER UPON IRON. 



299 



Table VII. 

Deduced from the foregoing Table VI., showing the Average Loss 
of all varieties of Cast Iron, 8tc., experimented on in each 
of the five conditions of immersion for a period of 387 days, 
on one square inch of surface. 



Condition of Iron. 


a. 


(3. 


r- 


e. 


6. 


Chilled Cast Iron 


6-826 


6-684 


6-025 


5-478 


1-372 






6-781 


2-170 


3-264 


4-283 


1-027 




No. 2. Bar Iron. Standard ... 


10-636 


12-570 


14-280 


7-300 


1-310 


Cast Iron; Skin removed 


8-230 


13-550 


13-920 


6-830 


2-590 


Cast Iron; Surface protected... 


4-214 


7-110 


2-466 


3-096 


0-488 



Table VIII. 

Of the Average Amount of Corrosion in Clear Sea Water, of 
various Cast and Wrought Irons, at the end of One Century, 
upon one superficial foot of surface, deduced from results of 
Table No. I. 



Class of Iron. 



Average 

less of 

Weight per 

superficial foot 

in 387 days 



Deduced ave- 
rage loss of 
Weight per 
superficial 
foot in a 
period of one 
century. 



Approximate 

depth of 

Corrosion in 

one century 

due to this 

amount of 



Welsh Cast Iron. Hot and cold 

Irish Cast Iron. Cold 

J Mixed Cast Irons. Scotch and 1 
\ Welsh; Irish and Welsh, &c. ... J 

J Scotch Cast Iron. Cold, and chiefly T 
\ hot blast J 

r Staffordshire, Shropshire and Glou-"| 
< cestershire Cast Irons. Hot and y 
[ cold J 

J Gray Cast Iron, mixed. Skin re- "1 
\ moved by planing _| 

J Derbyshire and Yorkshire Cast 1 
\ Irons. Hot and cold J 

f Wrought Iron. Standard Bar, No. 1 
\ 2. Doulais j 



grains avoir. 

859-968 
860-400 

948-960 
1067-680 

1083-744 

1185-120 
1212-480 
1531-584 



lbs. avoir. 
11-58 

11-59 
12-78 

14-38 

14-60 

15-97 
16-34 
20-56 



Inch. 

0-306 
0-306 

0-337 
0-379 

0-385 

0-419 
0-431 
0-543 



300 Table No. IX. — Cast Iron, in presence of Zinc 

Table of Experiments on the Amount of Action of ^Sea Water on Cast Iron 
these Metals, all exposing equal surfaces. 

Exposed Surface of Zinc, Copper or Alloy, ^ 199 square inch. 



g 


Atomic Constitution 
of Alloy. 


Specific Gra- 
vity of Alloy. 


Atomic 

Weight of 

Alloy. 


Weight of 
piece previous 
to immersion. 


Weight of 

piece after 

immersion 

for 1579 hours. 


Total 

loss of 

Weight. 




1. 




Cu 


8-667 


31-6 


504-90 


504-84 


0-06 


2. 


Zn + 


10 Cu 


8-605 


348-3 


576-70 


576-64 


0-06 




3. 


Zn-t- 


9Cu 


8-607 


316-7 


555-99 


555-93 


0-06 




4. 


Zn + 


8Cu 


8-633 


285-1 


560-17 


56013 


0-04 




5. 


Zn + 


7Cu 


8-587 


253-4 


530-86 


530-85 


0-01 




6. 


Zn + 


6Cu 


8-591 


221-9 


556-20 


556-20 


0-00 




7. 


Zn + 


5Cu 


8-415 


190-3 


499-10 


498-72 


0-38 




8. 


Zn + 


4Cu 


8-488 


158-7 


507-24 


507-22 


0-02 




9. 


Zn + 


3 Cu 


8-397 


1271 


468-36 


468-30 


006 




10. 


Zn + 


2Cu 


8-299 


95-5 


497-33 


497-33 


0-00 




11. 


Zn-i- 


Cu 


8-230 


63-9 


491-57 


491-57 


000 




12. 


2Zn + 


Cu 


8-283 


96-2 


482-24 


482-14 


0-10 




13. 


17Zn + 


8Cu 


7-721 


801-9 


34909 


348-92 


0-17 




14. 


18Zn + 


8Cu 


7-836 


8342 


387-40 


386-34 


1-06 




15. 


19Zn + 


8Cu 


8019 


866-5 


350-50 


350-13 


0-37 




16. 


20Zn + 


8Cu 


7-603 


898-8 


391-70 


391-14 


0-56 




17. 


21Zn + 


8Cu 


8058 


931-1 


353-80 


353-14 


0-66 




18. 


22Zn + 


8Cu 


7-882 


963-4 


334-08 


333-52 


0-56 




19. 


23Zn-j- 


8Cu 


7-443 


995-7 


356-24 


355-73 


0-51 




20. 


3Zn + 


Cu 


7-449 


128-5 


428-27 


426-46 


1-81 




21. 


4Zn + 


Cu 


7-371 


160-8 


440-39 


438-90 


1-49 




22. 


5Zn + 


Cu 


6-605 


1931 


420-26 


418-40 


1-86 




23. 


Zu 




6-895 


32-3 


425-85 


422-90 


2-95 




24. 


Fe 




7-138 













Table No. X. — Cast Iron, in presence of Tin and 

Exposed Surface of Alloys = 1-99 square inch. 

Table of Experiments on the Amount of Action of Sea Water on Cast Iron 
these Metals, all exposing equal Surfaces. 



OS 
!5 o, 



Atomic Constitution 
of Alloy. 



Sn + 10 
Sn + 9 
St\ + 
Sn + 
Sn + 
Sn + 
Sn -f 
Sn + 
Sn + 
Sn + 

2 Sn + 

3 Sn + 

4 Sn + 

5 Sn -j- 
Sn 
Fe. 



Cu 
Cu 
Cu 
Cu 
Cu 
Cu 
Cu 
Cu 
Cu 
Cu 
Cu 
Cu 
Cu 
Cu 
Cu 



Specific 

Gravity of 

Alloy. 



Atomic I Weight of 

Weight of piece previous 

Alloy. to immersion. 



8-667 
8-561 
8-162 
8-459 
8-728 
8-750 
8-575 
8-400 
8-539 
8-416 
8-056 
7-387 
7-447 
7-472 
7-742 
7-291 
7-138 



31-6 
374-9 
343-3 
311-7 
280-1 
248-5 
216-9 
185-3 
153-7 
122-1 

90-5 
149-4 
208-3 
267-2 
326-1 

58-9 



498-25 
551-10 
511-10 
501-76 
529-79 
515-00 
556-27 
518-36 
474-39 
528-20 
480-03 
492-29 
454-88 
457-75 
448-21 
415-80 



Weight of 

piece after 

immersion for 

364 hours, 



498-23 
551-10 
51104 
501-76 
529-75 
514-96 
556-11 
518-34 
474-20 
528-10 
479-93 
492-23 
454-88 
457-72 
448-20 
415-74 



Total 
loss of 
Weight, 



-02 
•00 
-06 
•00 
-04 
•04 
•06 
•02 
•09 
•00 
•00 
•06 
•00 
•03 
•01 
-06 



and Copper, immersed in clear Sea Water. 301 

in Voltaic Circuit, with Zinc, with Copper, and with various Atomic Alloys of 



Exposed surface of Cast Iron ^ 3*07 


square inches 
















Loss of Weight 






Weight of Cast 

Iron previous to 

immersion. 


Weight after 

immersion for 

15/9 hours. 


Total loss 
Df Weight. 


Loss of Weight 

per square inch 

of surface in 

387 days. 


per square inch 

of surface in 

387 days, referred 

to result of 

«77. 






903-19 


899-97 


3-22 


6-174 


11-37 






90319 


900-15 


3-04 


5-821 


10-72 






903-19 


900-33 


2-86 


5-468 


10-08 






903-19 


899-92 


3-37 


6-450 


11-88 






903-19 


899-44 


3-75 


7-173 


13-21 


maximum. 




903-19 


900-10 


3-09 


5-880 


10-83 






903-19 


900-23 


2-96 


5-594 


10-30 






903-19 


900-49 


2-70 


5-174 


9-53 






903-19 


900-12 


307 


5-880 


10-83 






903-19 


900-16 


3-03 


5-762 


10-61 






903-19 


900-30 


2-89 


5-527 


10-18 






903-19 


899-92 


3-27 


6-232 


11-48 






903-19 


900-62 


2-57 


4-939 


9-09 






903-19 


901-00 


2-19 


4-174 


7-69 




' 


903-19 


901-19 


2-00 


3-822 


711 






903-19 


902-90 


0-29 


0-553 


1-02 






903-19 


903-00 


0-19 


0-364 


0-67 






903-19 


903-02 


0-17 


0-323 


0-59 






903-19 


903-19 


0-00 


0000 


0-00 ■) 






903-19 


903-19 


0-00 


0-000 


0-00 






903-19 


903-19 


0-00 


0-000 


0-00 y 


minima. 




903-19 


903-19 


0-00 


0-000 


0-00 






90319 


90319 


000 


0000 


0-ooJ 


J = corrosion 
t of « 77. 




903-19 


900-86 


2-33 


4-468 


8-23 



•Copper, immersed in clear Sea Water. 

Exposed Surface of Cast Iron = 3-07 square inches. 

in Voltaic Circuit, with Tin, with Copper, and with various Atomic Alloys of 













Loss of Weight 






Weight of 

Cast Iron before 

immersion. 


Weight afler 

immersion for 

364 hours. 


Total loss 
of Weight. 


Loss of Weight 

per square inch 

of surface in 

387 days. 


per square inch 

of surface in 

387 days, 

referred to 

a 77. 






892-55 


891-84 


0-71 


5-894 


11-22 


minimum. 




892-55 


891-45 


110 


9-136 


17-41 






892-55 


891-24 


1-31 


10-881 


21-45 






892-55 


891-27 


1-28 


10-631 


20-25 






892-55 


891-36 


1-19 


9-884 


18-82 






892-55 


890-82 


1-73 


14-369 


27-38 






892-55 


890-80 


1-75 


14-535 . 


27-71 






892-55 


891-30 


1-25 


10-382 


19-78 






892-55 


891-70 


0-85 


7-060 


13-45 






892-55 


891-61 


0-94 


7-807 


14-89 






892-55 


890-82 


1-73 


14-369 


27-38 






892-55 


890-80 


1-75 


14-535 


27-71 






892-55 


891-71 


0-84 


6-977 


13-32 






892-55 


890-90 


1-65 


13-705 


26-12 






892-55 


891-02 


1-53 


12-708 


24-22 






892-55 


890-77 


1-78 


14-785 


38-19 


maximum. 




892-55 


89203 


0-52 


4-319 


8-23 


Corrosion of a77. 



302 



Table No. XI. — General Classification of 



Class of Iron. 



Hot or 
Cold. 



9. 
10. 
11. 

12. 
13. 
14. 

15.- 

16. 
17. 
18. 
19. 
20. 
21. 
22. 

23. 
24. 
25. 
26. 
27. 
28. 
29. 
30. 
31. 
32. 
33. 
34. 
35. 
36. 
37. 
38. 
39. 
40. 
41. 
42. 
43. 
44. 
45. 
46. 
47. 
48. 
49. 
50. 
51. 
52. 
53. 
54. 
55. 



Apedale 

Hardest procurable 

Gray Cast Iron, of varnish covering 

Pentwyn 

Calder 

Shotts 



Cold 



Doulais. (Finery pig). 



Arigna 

Burchill's 

Muirkirk 

Pentwyn. (Peculiar) 

Arigna 

Apedale. (Cylinder Iron) 

Pentwyn 

Calder, No. 1 -f Pentwyn, No. 2 1 

-I- Scrap / 

Gray Cast Iron. Skin removed . . . 

Monkland 

Clyde 

Parkfield 

A pedale 

Calder 

Arigna, ^. Scrap, ^ 

Calder, ^. Scrap, ^ 

Gartsherry 

Shotts 

Arigna 

Gartsherry 

Shotts 

VartegHill 

Calder 

Summerlie 

Madeley Wood 

Elsecar 

Cinderford 

Carron 

Gartsherry 

Muirkirk 

Monkland 

Doulais 

Arigna 

Shotts 

Lillicshall 

Shotts 

Caedtalon 

BufFery 

Caedtalon 

Carron 

Doulais 

Doulais 

Blaenavon 

Muirkirk 

Milton 

Calder 

Calder,^. Pentwyn, | 

Arigna, ^. Pentwyn, ^ 



Hot 
Hot 
Hot 

Hot 

Cold 
Cold 
Hot 
Hot 

Cold 
Hot 
Hot 



Hot 
Cold 
Cold 
Hot 
Hot 



Hot 
Hot 
Cold 
Hot 
Hot 
Hot 
Hot 
Hot 
Cold 
Cold 
Cold 
Hot 
Hot 
Hot 
Hot 
Hot 
Cold 
Hot 
Cold 
Hot 
Hot 
Hot 
Cold 
Cold 
Cold 
Cold 
Cold 
Cold 
Hot 
Hot 



No. 2. 
Scrap 

No! 2. 
No. 4. 
No. 4. 

No. 4. 

No. 1. 
No. I. 
No. 2. 
No.l. 

No. 3. 
No. 2. 

No. 2. 



No. 4. 
No.l. 
No.l. 

No.l. 
No.l. 



No. 2. 
No. 2. 
No. .3. 
No.l. 
No. 3. 
No. 2. 
No. 3. 
No. 2. 
No.l. 
No.l. 
No.l. 
No. 2. 
No. 3. 
No. 3. 
No. 3. 
No.]. 
No. 2. 
No.l. 
No.l. 
No. 2. 
No. 2. 
No.l. 
No. 2. 
No. 2. 
No. 3. 
No.l. 
No.l. 
No. 2. 
No.l. 



Silvery 



Micaceous 



Mottled 



Bright gray 



Dull 



gray 



Dark gray 



I 



the several Cast Irons of the foregoing experiments. 303 



Character in Working. 



Specific 
Gravity. 



How Cast. 



Least fusible ; thickening rapidly when 
fluid by a spontaneous "puddling ;" 
crystals vesicular, often crystalline, J 
incapable of being cut by chisel or j 
file; ultimate cohesion a maximum, 
and elastic range a minimum. 



"Very soft; feels greasy; peculiar mi-"| 
caceous appearance generally owing 
to excess of manganese ; soils the > 
fingers strongly ; crystals large ; 
runs very fluid ; contraction large. J 



Tough and hard; can be with diffi- 
culty filed or cut ; crystals large 
and small mixed ; sometimes runsi 
thick ; contraction on cooling 
maximum. 



Toughness and hardness most suitable 
for working; ultimate cohesion and 
elastic range generally are balanced - 
most advantageously ; crystals uni- 
form ; very minute. 



Less tough and hard than the preced- 
' ing ; other characters alike ; con- 
traction on cooling a minimum. 



Most fusible, remains long fluid ; 
exndes graphite on cooling ; soils 
the fingers ; crystals large and la- 
mellar; ultimate cohesion a mini- 
mum, and elastic range a maxi. 
mum. 



7-603 
7-624 
7-624 
7-629 
7-527 
7-158 

6-378 

7-015 
6-928 
6-980 
7-000 

7-308 
7-116 
7-017 
7-168 

7-138 
7-294 
7-140 
7-248 
7-268 
7-079 
7-134 

6-329 

7-115 
7-152 
7-141 
7-001 
7-183 
7-074 
7-064 
7-156 
7-115 
7-097 
7-049 
7-081 
7-074 
6-838 
7-124 
7-164 
6-809 
7-109 
7-205 
7-152 
7-030 
7-063 
7-020 
7-107 
7-159 
7-192 
7-143 
7-076 
7-073 
7-027 
6-978 
7-050 



Chilled 

Sand 

Chilled 

Chilled 

Sand 

Sand 

Sand 

Sand 
Sand 
Sand 
Sand 

Chilled 

Sand 

Sand 

Sand 

Sand 

Sand 

Sand 

Sand 

Sand 

Chilled 

Chilled 

Chilled 

Sand 
Sand 
Sand 
Sand 
Sand 
Sand 
Sand 
Sand 
Sand 
Sand 
Sand 
Sand 
Sand 
Sand 
Sand 
Sand 
Sand 
Sand 
Sand 
Sand 
Sand 
Sand 
Sand 
Sand 
Sand 
Sand 
Sand 
Sand 
Sand 
Sand 
Sand 
Sand 



Maximum density. 



/ Full of microscopic 
\ vesicles. 



r Minimum density 
L porous as No. 7. 



Minimum solid. 



304 



REPORT 1840. 



■TO 

s 








o 


.2 


• 


<u 


n 




3 




1— 1 


TS 


4^ 


c5 


.2 


4ii 

1 


H 


fan 








o 




^1 

O 






32 


c 




bf) 






c 





o ^ 



c 




Sm 


^ 








t<-l 




o 


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fao 

a 

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o 

-a 
so 



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s.s 

n-s 


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„. 


^ 




cs 


^ . 


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oc i-H «c OS eo CO <N 


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IH 




s 


b 




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o' 


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1^ 




lt5CO-*©-*«>.©C0 


O 


is«o — meot^oi© 






0503©©©©©'7l 


c 
2 


s 


<b5bt^b.b««^t»b. 


M 


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« 


CO 




*! ^ 




O 


^1 


^©•^(^^{©©-^CO 


2 


It 


c <N-<1"»>.05iM-*eO 


-=^ 1 








No. 
Expe 
men 


r^ (N CO -q! lo «> *i od 



s 
< 

Eh 



ON THE ACTION OF AIR AND WATER UPON IRON. 



305 



a 



O 9< 



1=3 o 






o ^ 



3 C 



O " 



cc 



s 



2(2 



1840. 



i-t GO 



5 



>o 1— 



t>. •> 



T O 



«0 r-i 



« X g 



X 


X 


U5 


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X 


X 



Sw 



306 REPORT — 1840. 

Table No. XIV. Showing the Chemical and Physical Properties 



1. 


2. 




3. 


4. 


5. 


6. 




c 












>. 






1 


Chemical 


Composition by Weight 


Atomic 


£ 








Constitution. 


per cent. 


Weight. 


2 


Colour, and order of 
















o 


Intensity. 




w 

1 


s — 


t + 


I — 


' + 


H= I 


1 






1 


Cu + 




100-00 + 





31-6 


8-667 


Tile-red. 




2 


10 Cu + 


Zn 


90-70 + 


9-30 


348-3 


8-605 


Reddish yellow 1 




3 


9 Cu + 


Zn 


89-80 + 


10-20 


316-7 


8-607 


Reddish yellow 2 




4 


8 Cu + 


Zn 


88-60 + 


11-40 


285-1 


8-633 


Reddish yellow 3 




5 


7Cu + 


Zn 


87-30 + 


12-70 


253-4 


8-587 


Reddish yellow 4 




6 


6 Cu 4- 


Zn 


85-40 + 


14-60 


221-9 


8-591 


Yellowish re:l 3 




7 


5 Cu + 


Zn 


83-02 + 


16-98 


190-3 


8-415 


Yellowish red 2 




8 


4 Cu + 


Zn 


79-65 -1- 


20-35 


158-7 


8-448 


Yellowish red 1 




9 


3 Cu 4- 


Zn 


74-58 + 


25-42 


127-1 


8-397 


Pale yellow. 




10 


2 Cu 4- 


Zn 


66-18 + 


33-82 


95-5 


8-299 


Full yellow 1 




11 


Cu 4- 


Zn 


49-47 + 


50-53 


63-9 


8-230 


Full yellow 2 




12 


Cu + 


2Zn 


32-85 + 


67-15 


96-2 


8-283 


Deep yellow. 




13 


8Cu + 


17 Zn 


31-52 + 


68-48 


801-9 


7-721 


Silver-white 1 




14 


8 Cu + 


18 Zn 


30-30 + 


69-70 


834-2 


7-836 


Silver-white 2 




15 


8 Cu + 


19 Zn 


29-17 + 


70-83 


866-5 


8-019 


Silver-gray 3 




16 


8 Cu + 


20 Zn 


28-12 + 


71-88 


898-8 


7-603 


Ash-gray 3 




17 


8 Cu + 


21 Zn 


2710 + 


72-90 


9311 


8-058 


Silver-gray 2 




18 


8 Cu 4- 


22 Zn 


26-24 + 


73-76 


963-4 


7-882 


Silver-gray 1 




19 


8 Cu + 


23 Zn 


25-39 + 


74-61 


995-7 


7-443 


Ash-gray 4 




20 


Cu 4- 


3 Zn 


24-50 + 


75-50 


128-5 


7-449 


Ash-gray 1 




21 


Cu + 


4 Zn 


19-65 + 


80-35 


160-8 


7-371 


Ash-gray 2 




22 


Cu + 


5 Zn 


16-36 + 


83-64 


1931 


6-605 


Very dark gray. 




23 


+ 


Zn 


+ 100-00 


32-3 


6-895 


Bluish gray. 





Table No. XV. Showing the Chemical and Physical Properties 



1 


Cu + 




100-00 + 





31-6 


8-667 


Tile-red. 






2 


10 Cu + 


Sn 


84-29 + 


15-71 


374-9 


8-561 


Reddish yellow 


1 




3 


9 Cu + 


Sn 


82-81 + 


17-19 


343-3 


8-462 


Reddish yellow 


2 




4 


8 Cu + 


Sn 


81-10 + 


18-90 


311-7 


8-459 


Yellowish red 


2 




5 


7Cu + 


Sn 


78-97 + 


21-03 


280-1 


8-728 


Yellowish red 


1 




6 


6 Cu + 


Sn 


76-29 + 


23-71 


248-5 


8-750 


Bluish red 


1 




7 


5 Cu + 


Sn 


72-80 + 


27-20 


216-9 


8-575 


Bluish red 


2 




8 


4 Cu + 


Sn 


68-21 + 


31-79 


185-3 


8-400 


Ash-gray. 






9 


3 Cu + 


Sn 


61-69 + 


38-31 


153-7 


8-539 


Dark gray. 






10 


2 Cu + 


Sn 


51-75 + 


48-25 


122-1 


8-416 


Grayish white 


1 




11 


Cu + 


Sn 


34-92 + 


65-08 


90-5 


8-056 


Whiter still 


2 




12 


Cu + 


2 Sn 


21-15 + 


78-85 


149-4 


7-387 


Whiter still 


3 




13 


Cu + 


3 Sn 


15-17 + 


84-83 


208-3 


7-447 


Whiter still 


4 




14 


Cu + 


4 Sn 


11-82 + 


88-18 


267-2 


7-472 


Whiter still 


5 




15 


Cu + 


5 Sn 


9-68 + 


90-32 


326-1 


7-442 


Whiter still 


6 




16 


+ 


Sn 


+ 10000 


58-9 


7-291 


White 


7 





Abbreviations used in column 7th to denote character of fracture : — 
F.F. Fme Fibrous. C. Conchoidal. V.C. Vitreo-Conchoidal. V. Vitreous, 
are = 1. The numbers in cohnnn 6th denote intensity of shade of the 
specific gravities were determined by the method indicated in Report " On 

Tlie ultimate cohesion was determined on prisms of 0-25 of an inch square, 
given are those which each prism just sustained for a few seconds before 



ON THE ACTION OP AIR AND WATER UPON IRON. 307 

of the Atomic Alloys of Copper and Zinc of Table No. TX. 





7. 


8. 


9. 


10. 


11. 


12. 


13. 


14. 






c 
•2.C 


>. 


^ ' 


«- 


>. 










-il 




3 j= 


s 
•a 


3 




Relation to 




3 


Is 


3 

a 

Cm 


^& 




1 

Cm 


Cliaracteristic Properties, in 
Working, &c. 


Cast Iron, in 
)re5ence of a 

solvent, i. e. 
Sea Water. 






5 * 


■a 


•3 ti 


■H 


■2 










Tons. 


5 


o 


O 


o 








E. 


24-6 


8 


1 


22 


15 


Well known. 


<u g 




C.C. 


121 


6 


13 


21 


14 


•\ 


i|.s 




F.C. 


11-5 


4 


11 


20 


13 


Several of these are 


S g c 




F.C. 


12-8 


2 


10 


19 


12 


Similar, &c. >- malleable at high 


C !8 2 O 




F.C. 


lS-2 


9 


9 


18 


11 


temperatures. 






F.F. 


141 


5 


8 


17 


10 




S " 33 ^ 




F.C. 


137 


11 


2 


16 


9 


Bath Metal. 


le Al 

rosio 

Wal 

eir pi 




F.C. 


14-7 


7 


3 


15 


8 


Dutch Brass. 




F.C. 


131 


10 


4 


14 


7 


Rolled Sheet Brass. 


J o 2:5 




F.C. 


12-5 


3 


6 


13 


6 


British Brass. 


•SQ V2 




C.C. 


9-2 


12 


5 


12 


6 


German Brass. 






C.C. 


19-3 


1 


7 


10 


6 


„ Brass, Watchmakers'. 






C. 


21 





22 


5 


5 


Very brittle, 




a 5 a 




V.C. 


2-2 





23 


6 


5 


Very brittle. 


Too hard to file or 


S '-^ 




C. 


0-7 





21 


7 


5 


Very brittle. 


turn, lustre nearly 


lli^ 




V. 


3-2 





19 


3 


5 


Brittle, 


equal to Speculum 


^""S c 




C. 


0-9 





18 


9 


5 


Brittle, 


Metal. 


g-o >.-£ 




C. 


0-8 





20 


8 


5 


Very brittle, J 




.^ J. « j; 




F.C. 


5-9 





15 


1 


5 


Barely malleable. 


^ll.^ 




F.C. 


31 





16 


2 


4 


Brittle. 


sg«l 




F.C. 


1-9 





14 


4 


3 


White Button Metal. 






F.C. 


1-8 





17 


11 


2 


Brittle. 




T.C. 


15-2 


13 


12 


23 


1 


Brittle, well known. 


J <'S"" 



of the Atomic Alloj's of Copper and Tui of Table No. X. 



E. 


24-6 


1 


2 


10 


16 


F.C. 


161 


2 


6 


8 


15 


F.C. 


15-2 


3 


7 


5 


14 


F.C. 


17-7 


4 


10 


4 


13 


V.C. 


13-6 


5 


11 


3 


12 


V. 


9-7 





12 


2 


11 


C. 


4-9 





13 


1 


10 


C. 


0-7 





14 


6 


9 


T.C. 


0-5 





16 


7 


8 


V.C. 


1-7 





13 


9 


7 


T.C. 


1-4 





9 


11 


6 


C.C. 


3-9 





8 


12 


5 


C.C. 


31 





5 


13 


4 


C.C. 


31 


8 


4 


14 


3 


E. 


2-5 


6 


3 


15 


2 


F, 


2-7 


7 


1 


16 


1 



Well known. 

Gun Metal, &c. 

Gun Metal, &c. 

Gun Metal and Bronze, 

Hard Mill Brasses, &c. 

Brittle, 



All these Alloys found 
occasionally in Bells, 
with mixtures of Zn 
and Pb. 



Brittle, 
Crumbles, 
Crumbles, 
Brittle 
Small Bells, brittle, 
„ brittle. 

Speculum Metal of Authors. 

„ Files, tough. 

„ Files, soft and tough 

Well known. 



C/3 OJ <u o 

"ill 

o n c h 



_ ■" = c 
S o o = 

•«5 fci ^ 



5; •SO E 



F.C. Fine Crystalline. C.C. Coarse Crystalline. T.C. Tabular Crystalline. 
E. Earthy. The maxima of ductility, malleability, hardness, and fusibility, 
same colour. The atomic weights are those of the hydrogen scale. The 
Action of Air and Water on Iron." Trans. Brit. Assoc, vol. vii. p. 283. 
■without having been hammered or compressed after being cast. The weights 
disrujjtion. 

X 2 



308 



REPORT 1840. 



> 


.a 


X 


*% 




(L> 


n 


CO 


■< 


-TS 


H 


s 



fc/D 

3 



o 





^ 








"3 




.S 




V 




> 








« c ^ -J 




<u 3 c u 




le S o 4) 




02 1—1 I- -»^ 




. . '-' 02 




g S B C 




ss is 




1 












« 






2 


.'6 . .'6 . .-a .-ti-s .■S-S'^'d-st;-"''^' .rs^i . 


?o 




.1— t ..—4 . .,— . ,00 .OC.— ■^-O^-O'— ..— <o 






O O O * "^ 3" "^ o O '^ U '^ CJ O* 




1 






>. 






'> 








^■^«>.eO«>»0'M«Oit5lOMOOifl-HOW-*C<5050C50mCO 




o 


«0O!O0C-"O'J5if505Cr5COO50iC<5inro-HO»»t^Ml^CC — 


lO 


■^'TjOoiaiaDioinro — 05«>.i>.«Oinif;ir5^c;xac-*co-* 




U 


cricoQp»>«t>.i>.t^t^b»t-»wco!p«p«p«p«p«pir5ioinioio-* 




J_ 


t^t>.^«^«^>.^<^>^«^«^«■>>^«^«^«^.^.t«.^^>^«^«^<^«^<^« 




■s 


■a -d T3 -a -d _ _t3 "S _ _ 












■fl< 












c'o'o § S^o S"© c'o'o a'o'o'o'o'o'o'o'c c'c'orj 
C3'— '■* c3 a-^ cj-" rt^~' tat— t-iHHl-t.^ — — " ci'— >— ' 




1 




X 


K KS H K K = 




6 


d . 


M 


s 

1 


d ci d ci . d t3 -d • .d .^ • • -d • • -odr-; 




£ 


fe 
































u 


















































:a 


















































1 




i 












































"^ 53 
















































J* o 




t3 












































§g 




g 














































^ 










































go 




































>^ 












o 












-~- 1 
















(U 










rv* - 




w 
















« 






c^ 






o^SooS 


^^^-s M 






»i 


M 
G 




mora) . 
radley) 
iscoe's) 
ninghai 
Ed (Bra 
Bar ... 


1 


); soft 
adley) , 
brdshir 
lOssihle 
of Dei 
(Bank 
Doulais 
shire ; 
;hill's) . 
Doulais 
Doulais 
shire ; 
Steel . 




a 
1 


ister Steel (Roscoe' 
'cdish Iron (Danne 
ring Steel, Soft (B 
st Steel, Tilted (Re 
.masked Iron ; Birii 
ring Steel, Temper 
5gotted Scrap Iron 
\v Moor Boiler Pla 
ear Steel (Roscoe's 
st Enghsh Bar (Br 
d Short Bar ; Staff 
st Steel ; hard as ji 
lished Bar ; Forest 
mmon Boiler Plate 
lished Welsh Bar ( 
mmon Bar; Shrop 
Id Short Bar (Bmc 
ddled Welsh Bar ( 
lished Welsh Bar ( 
mmon Bar ; Shrop 
r Iron of Roscoe's 
ddled Bar (Cinderf 
ddled Welsh Bar ( 
st Steel in the Inge 














^|Sci.a"&,c30j=««ca.i;o.so03.sora33ea 






m(/3»3oQc«ii.i-5»3s;pso6i.o[i<oo(xci-iOO&«(xo 




s 


'"©Jto-^inwt-CocovO— '^'«-*»0«Ct»CxOJO-H<NeO-3< 




3 


rt«^_rtF-.^«-Np-.(MS<l(N(N.Jq 




» 





309 



Report on some Observations on Subterranean Temperature. 
By Robert Were Fox, Esq. 

Having already given, through the Philosopliical Magazine*, 
a summary of the observations on subterranean temperature 
wliich I had previously published from time to time, I must, in 
complying with the unexpected invitation of the British Asso- 
ciation, necessarily include in the present Report many of the 
details contained in that memoir. 

Early in the year 1815, my friend Joel Lean stated to me 
his conviction, that the high temperature observed in our 
mines existed in the earth itself, increasing with the depth ; 
and shortly afterwards his brother Thomas Lean, at our johit 
request, kindly made many experiments in Huel Abraham 
Copper Mine, of which he was the manager, in order to test 
the correctness of this view. The results obtained by him 
tended to confirm it very unequivocally ; and so did another 
series, made in the same year at my request, in Dolcoath 
Mine, by John Rule, jun., one of the superintendents. Many 
other individuals have since obligingly carried on similar ob- 
servations for me in different mines, all showing that the sub- 
terranean temperature increases, in some proportion to the 
depth from the surface. The ratio of its increase at different 
depths, and the causes which exercise a gi'eater or less influ- 
ence upon it, have, however, hitherto been undecided. 

I have elsewhere endeavoured to show, that the rate of in- 
crease is not so considerable at deeper excavations as at those 
which are shallower ; and the subjoined Tables will, I think, 
exhibit this point in a satisfactory manner, as far, at least, as 
the results obtained in some of the mines of Cornwall and 
Devonshire, which I have published from time to time, may be 
considered an authority. 

* Phil. Mag. 1837, vol. ii. p. 520. 



Table I. 



Table I. — Showing the Results of Observations on Subterranean 
the Ratio of its Increase at different Depths. The experiments 
the deepest levels or accessible parts of the respective mines. 



es 



Mines and Localities. 



C. stands for Copper Mine. 
T. ditto Tin ditto. 
G. for Granite. 
K. for Killas. 



1822 
1827 



1827 
1822 



1822 



1820 
1820 
1820 

1822 

1820 
1830 
1824 

1824 
1824 
1827 

1827 
1827 

1822 

1819 
1822 

1822 
1822 
1822 
1820 
1820 

1820 
1827 
1827 
1820 



South Huel Tovvan, St. Agnes, C.K. in cistern"! 

or reservoir at the bottom J 

Huel Wellington, near Camborne, C.K. small] 

streain from Western end of deepest level J 

Ditto ditto ditto Eastern ditto 

East Liscombe, near Tavistock, C.K. in deepest 1 

cistern J 

Huel Unity- Wood, Gwennap, Tin, K. in ditto 



Huel Unity, Gwennap, T. and C.K 

Ting- Tang, ditto C.K., in the lode 

Huel Gorland, ditto C.G 

Means of depths and temperatures. 
Beer-Alston, Beer-Ferris, Devon, Lead and Sil- 
ver K., in deepest cistern 

Huel Squire, Gwennap, C.K., in deepest cistern. 
Huel Rose, Kewlyn, Lead, K., deepest level .... 
Chasewater, Chasewater, T.K., in E. end of 

deepest level 

Ditto ditto, W. end of deepest level .... 

Huel Trumpet, W'endron, T.G., in deepest level... 
Huel Jewel, Gwtnnap, C. and T.G., 40 fathoms 1 

to the E. of shaft, and 4 feet from end of level J 
Ditto ditto, 18 ditto, W. ditto, and 4 feet ditto 
Huel Vor, near Helston, T.K. in deepest level, "I 

4 fathoms from shaft J 

^Consolidated Wines, Gwennap, C.K. in lode, 16^ 

fatlioms E. of Job's shaft 

Treskerby, near Redruth, C.G. in lode 

Poldice, Gwennap, T. and C.K., bottom of) 

Trussel's shaft J 

Ditto ditto ditto of Oppy's shaft .. 

Consolidated Mines, C.K., bottom of Job's ditto... 
Ditto ditto ditto of Taylor's ditto... 

Huel Damsel, Gwennap, C.G, 



United Wines, ditto, C.K., end of level N. of | 

Sampson's shaft, and supposed 6 feet from lode j 

*Ditto ditto ditto, W. of ditto in lode... 

Huel Alfred, near Hayle, C.K., E. end of level... 

Ditto ditto ditto, W. ditto 

*United Mines, K., in the lode E. of shaft 

Means of depths and temperatures 



IMeans of temperature 

Deduct mean temperature of climate 



Means of depths in fathoms, 
temperature above tlimate .. 



md of excess of 1 



Which being estimated at the depth of 100 fa-" 
ihoins, cive 



Computed temperature at . 



Depth from 
Surface in 
Fathoms. 



90 
110 



100-00 



128 
138 



140 



150 
150 

152 

152 

160 



Temperature 

of Rock, 
Fahrenheit. 



■ G7°-00 



116-25 



123-12 



100-00 



lOOOO 



74-25 



70-6i 
50-0« 



20-6: 



Ur7i 
50-0< 



66°-7i 



Temperature in difFerent Mines in Cornwall and Devonshire, and 
were, with a few exce2itions (distinguished by an asterisk), made in 



Depth in 
Fathoms. 



45 

50 

50 

82 
8S 



5 ^ t^" 



62-60 



120 
120 

128 

128 
128 

138 
139 

140 

144 

114 
150 
150 



155 
155 



— 60°-60 

66-5 

63 

75 

68 
65 

71 
69 



138-50 



100-55 



100-00 



10000 



72-11 



66-35 
50-00 



16-35 



Depth in 
Fathoms. 



5"S-S 



50 



110 



120 

128 

128 
128 



136 



8000 



58"'-5 



68 

— 63°-25 



.c o - 



45 

50 
50 

82 
86 



Mean 
Depth. 



69 



128-00 



•70-60 



104-00 



1G-2G 
5000 

66-2611 



100-00 



lOOOO 



66-92 
50-OU 



10-92 



16-27 

50-00 

66°-27 



90 
110 
110 

120 

120 
120 



128 
128 
138 
137-5 

140 
140 



150 

150 

152 

152 
155 
155 



... 60" 

57 
58 
64 
64 



62-60 



66 

68 
68 

66-5 

68 
71 

71 

64 

70 
71 
69 

72 

76 



Ratio of Depth 

to a given 

Incrt'ase of 

Tem.ieraturc 

= 10=. 



Surface = 50'' 



60''-60 
- 50 -00 



10 -60 



fms. 
01-59-05 = 10"^ 



132-81 
- 59-05 



73-76 



70-13 
- 60-00 



10-13 or72-81 = 10° 



131-86 = 70° 



312 



Table I. 



35 



42 



Mines and Localities. 



0| 
o 



1819 



30 

31 

32 
33 
34 I 1820 



1822 



1830 
1830 



1837 

1837 
1815 
1824 

1824 
1830 
1837 



1837 



43 


1837 


44 


1837 


45 


1822 


46 

47 


1815 
1837 


48 
49 


1819 
1837 



United Mines in bottom of a shaft, K., 8 fathoms"! 

S. of lode J 

Huel Friendship, near Tavistock, C.K., in deepest! 

level i 

Poldice, at bottom of shaft 

Ting Tang, in deepest cistern 

United Mines, in a level 

*Tresavean, Stythians, C, bulb of therm. 2 ft. 1 

10 in. in lode in killas, at 3 fms. from granite J 

♦Ditto ditto, in killas 10 fms. from granite... 

Huel Abraham, Crowan, C.K., at bottom , 

Stray- Park, Camborne, stream from E. end of 1 

deepest level J 

Ditto ditto ditto W. ditto... 

Huel Vor, T.K., in deepest level 

*Tresavean in granite, 20 fms. from killas, and \ 

12 ft. from lode, bulb 2 ft. 10 in. deep J 

Means of depths and temperatures... 

Levant, St. Just., near Land's End, T. and C.,"| 
end of deepest level W. of enguie-shaft, in >■ 
killas, bulb 3 ft. deep J 

Ditto, near stream flowing into levelE. of engine- \ 
shaft, granite J 

Ditto, near bottom of engine-shaft in granite, I 
bulb 3 feet deep J 

Dolcoath, Camborne, C, in deepest level, bulb \ 
3 feet deep in granite, from 19 to 20 months... J 

Ditto, spring of water in bottom of engine-shaft... 

' Tresavean in lode in G., 100 fms. from killas, "I 
bulb 3 feet deep J 

Dolcoath, water in bottom of engine-shaft 

•Tresavean in lode in G., 60 fms. from killas, bulb "I 

2ft. 10 in. deep J 

Means of depths and temperatures 



1837 
1837 



1837 
1837 



Means from 170 to 250 fms. from the surface.. 

Deduct computed temperature at 100 fms. 1 

deep, as given before J 



Difference 



Increase of temperature in the second 100 fms, 
Depth and temperature estimated before 



Depth in 
Fathoms. 



200 
200 



210 
220 

230 
230 

234 

250 



Temperature 

of Rock, 
Fahrenheit. 



76° 

76 



74-2 



232-80 



21806 
10000 



203-33 75°-40 

78 

80 
76 

78-2 

82-5 



• 78°-94 



11806 



Temperature deduced from the above at 200 1 
fms. deep J 

Tresavean, in lode granite 60 fms. from killas, 1 

bulb 2-10 ft. deep J 

Consolidated Mines, K., bulb 3 feet deep in a 1 

X level, 24 fms. from lode J 

Ditto ditto ditto 10 ditto... 
Ditto ditto ditto, in Ihe lode 



10000 
10000 



20000 



262 

290 

290 
290 



7717 
66-75 



10-42 



= 8-82 
66-75 



75°57 



82°-5 1 S.S 

I > ** 

85-3 i i.2 

86-3 Ifl 

92 |2 

Jo" 



t No. 32 not included in tlie mean ; and a few other results omitted in the last columns, in consequence 
of their differing so much from the mean and from the temperature usually lound at similar depths. 



{continued.) 














313 


Depth in 
Fathoms. 


lit 


Depth in 
Fathoms. 


Temperature 

of Air, 
Fahrenheit. 


■lit 


Mean 
Depth. 


Il 
H 


Mean 

Temperature 

and 

Increase. 


Ratio of Depth 
to a given In. 

crease of 

Temperature 

= 10°. 


170 


76° 







170 




76° 






170 


64-5 
















176 
178 
200 


99t 

82 
88 






200 




7Q 






200 


78" 


200 


78° 


200 
200 




76 

78 






200 


72 







200 




72 






200 
209 


74 

79 






200 
209 

210 




74 
79 

74-2 






190-87 


— 76°-69 


200-00 


— 78°-00 


220 




78 






220 


78-5 








220 
230 
230 




78-5 

80 

76 






233 


82 







233 
234 





82 
78-2 






239 


82 








239 
250 




82 
82-5 






230-66 


— 80°-83 
















210-76 


780-76 


200-00 


78-00 


1 100-00 


66-26 


100-00 


66-27 


262 




82-5 






110-76 


12-50 


10000 


11-73 


10000 
100-00 


11-27 

66-26 


10000 
10000 


11-73 
66-27 


i; 200-00 


77°-53 


200-00 


78°-00 


















290 




85-3 








Add pr< 


>vious cstima 


Less 

Difference 

ted amoun 


290 


225-63 
131-86 


86-3 
Temj 


78-76 
70-00 


or 107-04 = 10 
131-86 = 70 


is of D 


93-77 


8-76 


epth and 


erature . . 


- 1 Total Depth and Temperature compu 


ed 


238-90 = 80 






1 



















314 



REPORT 1840. 



Mean results of temp, at 100 fathoms under the surface. 

Rock = 16-75 + 50 = 60-75 
Water = 16-26 + 50 = 66-26 
Air = 16-27 + 50 = 66-27 



Mean 16-43 



66-4<3 



At 200 fathoms under the surface. 
Rock = 8-82 + 66-75 = 75-57 
Water = 1 1-27 + 66-26 = 77-53 
Ah- = 11-73 + 66-27 = 78-00 



Mean 10-61 



77-03 



Table II. 

Temperature observed in different parts, but not the deepest, 
of the following mines, in Cornwall and Devon ; Huel Abra- 
ham, Dolcoath, United Mines, Treskerby, Huel Squire, 
Ting Tang, Huel Gorland, Huel Damsel, Chasewater, Huel 
Unity, Huel Vor, Huel Unity- Wood, Beer Alston, Poldice, 
Consolidated Mines, Huel Friendship, Huel Maid, Nangiles, 
North Huel Virgin, Tresavean, etc. 



Depth 

in 

Fathoms. I 



Temperature, Fahrenheit. 



o Ratio of Depth to a given 

; J2 &! Increase of Temperature. 



(g=^ Fathoms Temp. General Mean 



10 to 20 58. + 57. 56. 53 

20... 30'6l.55.64. +56.58 „ 

30 ... 40 56. 60. 54. 56. + 61. 62. 06. 62. 6l. 5/. 60. 5/. 55. 60. 

4(1... 50 58. do. 60. 60. 60. + 63. 58. 58 

50... 60|60.62.60. 58. + 63.63.61.61.62.60.57 

60... 70l 61. + 62.64.61.61.59.68 

-0... 80 64.62 64.64.62. + 64.66.-0.65.64.64.68.67. .. 

80... 90 66.64.63.64.66. +65. 6y. 62. 67 



90... 100 
100... 110 



150. 
160. 


.160 
.170 


170. 


.180 


180. 


.190 


190. 


.200 



56-00 
58-80 
58-36 
59-62 
60-64 
62-29 
64-92 
65-11 



53.67.72. 64.65. + 66.79.70.70.66.56.68-5 

70. 68. 65. 64. 64. 66. + 68. 68. 69. 65. 66 

68. 66. 66. 66-5 + 70. 72. 72. 70. 66. 68. 71 

63.62.70.66.72.74.74.63.72.68. + 71.76.73.74.62.73.70. 

67.74-5. 67.78. 70.80. 72. + 72. 73. 70. 78. 72. 81. 75 

76.80. +74.72. 80.71-5 

75. 69. 74. 66. 4- 70. 68. 73 

64-5. 77. 84. 4. 71. 71. 73. 66. 76 , 

75-5. 76. 72. 69. 86. 87. + 74. 72. 74. 72. 73 

75-5.74.74.+ 

+ 74.71.71.74.77.78 



66-76 
66-64 
68-68 
6i*-59 
73-54 
75-58 



74-50 
74-17 



60-72 
-50-00 



fmg, 
or 46-64 = 



or 79-09 = 



74-72 
70-00 



Computed from Means of Depth and Temperature 



The figures on the left iiidicate Ihe temperature of the rock, rubbish, or water ; tho«c on the r et t 
the air ; in the respective ihincs, they are divided by +! ^ 



REPORT ON SUBTERRANEAN TEMPERATURE. 315 

The first Table contains results obtained in the deepest 
galleries or accessible parts of mines, a few only excepted, in 
which cases the experiments were made with great care in the 
rock at superior levels, and at a distance from other excava- 
tions. Some of the reasons for preferring the former to the 
genex'ality of results derived from the upper parts of mines 
have been stated on previous occasions, and they appear to be 
so obvious as to render repetition needless. 

The rate of increase of temperature, as it respects the rock 
or rubbish, and the water and air, appears to have been 
tolerably consistent. The mean is 16°*4o at 100 fathoms deep, 
and 27°*0c> at 200 fathoms deep ; the augmented temperature 
of the first hundred fathoms being to that of the second hun- 
dred fathoms, as lG*4o to lO'GO. 

Some of the results from which these means are deduced 
are rather uncommonly high, and probably the general mean 
temperature observable in our mines would be more nearly 
represented by their omission, thus reducing both the above 
means a little ; but if this were done, it does not appear that 
their relations to each other would be essentially altered. 

In the last columns are included all the results obtained in 
the rock, water, and air, with the exception of a few which seem 
to be in unusual excess, and they give, in round numbers, 
A temperature of 00" at 59 fms. below the surface. 
„ 70° at 132 „ „ 

and 80° at 259 „ „ 

Being an increase of 

10° at 59 f i:s. deep, or 1° in 35-4 feet, 

of 10 more at 73 fms. deeper, or 1 in 43'8 feet, 

and of 10 ,, 114 fms. still deeper, or 1 in G4'2 feet. 

The second Table shows the temperature observed in the 
rock or rubbish, water, and air, in various mines at different 
depths, but not in the lowest excavations. It will not there- 
foi'e, perhaps, be considered to possess much value beyond 
what is derived from the great number of the results, and the 
probability that the mean which they indicate may be an ap- 
proximation to the truth. The figui-es only are given, without 
any details, and are to be found in my papers inserted in the 
Transactions of the Cornwall Geological Society, and in the 
Philosophical Magazine. 

Many of the observations, even in the first Table, may per- 
haps now be considered very imperfect, having been obtained 
when the inquiry was in its infancy. The method which I 
have more recently adopted, of having the bulbs of different 
thermometers buried at different depths at the bottom of a 
mine, appears to be as unexceptionable as the circumstances 
of the case will admit of; but, in fact, I have always considered 



316 



REPORT — 1840. 



that the best expermients on subterranean temperature, in- 
fluenced as it is by so many disturbing and conflicting causes, 
can be regarded as affording only approximations to the truth, 
and, in a greater or less degree, in proportion as they are more 
or less numerous, and made in different localities. 

The second Table exhibits increments of temperature equal 
to 10° each, at intervals of about 47, 79, and 125 fathoms of 
descent. The comparative augmentation of temperature at 
small depths exhibited in this Table, and its reduction at greater 
ones, may perhaps be more or less attributed to the ascent of 
warm air and vapour from the deeper galleries of the mines, 
and the descent of colder currents into these parts. 

I have taken the mean temperature at 50° Fahr., and it is, 
I think, clearly not more than this in the mining districts of 
Coi'nwall and Devon, judging from the experiments I have 
instituted on the temperature of the ground at three different 
stations, at the depth of three feet, which give a mean of 
49°"86* for the year, at a mean elevation of about 240 feet 
above the level of the sea ; and also from the meteorological 
registers kept in this neighbourhood, some of which appear in 
the Cornwall Polytechnic Society's Reports and the Annals 
of Philosophy t- 

I add a diagram or section, by way of illustration of the 
first Table. 






■ — - 




— 


JO' 
X 
'60'' 


^__,:s^^^--^ ^^ 


-^^ 


. ^ y 






y^ 


JO" 


a t 


c 


/ - 



so" 



I 



* See Transactions of the Cornwall Geolog. Society, vol. iii. pp. 326-328. 

f In the Annals of Philosophj', vol. xvi. ]). 371, 1820, the mean tempera- 
ture of eleven years at Penzance is stated to have been only 49°. The eleva- 
tion of this town above the sea-level is inconsiderable, and perhaps 100 to 200 
feet below the average of the mining districts where the experiments were 
made. 



REPORT ON SUBTERRANEAN TEMPERATURE. 317 

The upper line represents the surface of a given district 
and the diagonal one the line of junction of granite and killas' 
The dotted lines show the mean intervals at which, according 
to the first Table, there appears to be a progressive augment- 
ation of 10° Fahr.; but the tortuoua line a: y might more 
properly indicate the very irregular depths at which a criven 
amount of temperature exists, even in the same neighbour- 
hood. ^ 

^ The isothermal lines are represented as having a small 
mchnation downwards as they pass from the killas into the 
granite, to illustrate the inferior temperature of the latter. 
Ihe amount of this difference is undoubtedly very variable in 
different localities, and sometimes little or nothing. I have, in 
my earlier papers on subterranean temperature, noticed the 
tact, although I did not ascertain the extent of the difference* 
nor have I considered it so high, upon the whole, as Mr. W. j' 
Henwood has done ; but he has investigated this point much 
more fully than I have, and made numerous experiments in 
reference to it. 

The intervals between the isothermal lines seem to vary 
much m different places ; but I think it will be found to be a 
general fact, that the temperature increases less rapidly in 
descending in proportion to the depth of the stations in the 
mines Jt so, the conducting power of the rocks cannot, I 
apprehend be considered as the immediate or proximate cause 
of these pha;nomena at the greatest depths hitherto attained ^ 
nor is it to be supposed, that a depth where the heat is trans- 
mitted through this medium only will ever be reached by 
man, seeing that the temperature at the bottom of some deep 
mines is already almost as great as is compatible with active 
operations. 

I have often suggested, that the differences which are found 
to exist in the increments of temperature in different places 
and strata, are principally caused by the circulation of water 
under the surface; and the tendency of warm water to ascend 
through cooler portions of that fluid is quite consistent with 
the fact of the ratio of increase being greater at small than at 
considerable depths. Wherever the facilities are the greatest 
tor the ascent of these currents, such, for instance, as exist in 
veins, faults or fissures in the strata, and frequently at the 
junction of different rocks, there the subterranean temperature 
IS usually found in excess, or above the mean. Let the points 

* It seems almost needless to remark that, in comparing the subterranean 
temperature m different rocks, reference should be had to the depth of the 
stations at which the observations were made. ^ 



318 REPORT — 1840. 

a, b, and c, in the section, each represent the deepest part of 
a mine, all three being in killas. If fissures or veins, pervious 
to water, be supposed to descend from these points to a much 
greater depth, where the temperature is considerably higher, 
it is evident that the warmer water will rise, and the cooler 
sink and take its place; and thus an excess of temperature will 
be imparted to a, b, and c by the agency of the circulating 
water. It matters not whether the ascending currents proceed 
from dm the killas, oryin the granite, or through the line of 
junction h e, to 6 or c; in any of these cases corresponding 
effects will be produced, and a, b, and c will be at a higher 
temperature than other points at equal depths in their vicinity, 
more or less distant from fissures, veins, etc. ; the former dif- 
fering only in degree according to the depth, or rather tempe* 
rature of the parts where the currents originate, and the 
obstacles they meet with in their passage. Nos. 51, 52 and 
53, in Table I., may be referred to as examples of this differ- 
ence. In this case, the vein in the Consolidated Mines, at 
290 fathoms deep, was found to be at 92°, whilst the rock at 
the same depth, and only 10 fathoms from it, was at 86° 3'; 
and at 24 fathoms from it, 85° 3'. These facts, with others 
which might be mentioned, seem to show how poor a con- 
ductor of heat the rock is, and they give additional support to 
the views advocated in this Report. 

The circulation of water under the surface, and its influence 
on subterranean temperature, is moreover, I apprehend, pro- 
moted by the agency of electricity, which is in such active 
operation in metalliferous veins*, since it will cause water to 
pass through many substances that would otherwise be imper- 
vious to it. The simplest, and almost the feeblest voltaic 
combinations, are capable of illustrating this remarkable pro- 
perty, and will transmit water, especially if it contain saline 
ingredients, through the most tenacious clay, etc., in any direc- 
tion, either horizontally or vertically. 

I will now conclude this Report with the expression of a 
hope, that the ratio of the increase of subterranean tempera- 
ture may be more fully investigated, not only in this countrj' 
but also in others, where the climates are the most dissimi- 
lar f, in order to determine the modifications produced by 

* I observe, by the Edinburgh New Philosophical Journal, No. 55, that 
Prof. Reich has detected electric currents in Himmelfahrt Mine, near Frey- 
berg, although they were evidently much less energetic than those prevailing 
in our mines of copper, etc. 

t Note. — Might not this object be accomplished, as it respects some of the 
mines in America, through the instrumentality of the mining companies, if 



RKPORT ON SUBTERRANEAN TEMPERATURE. 319 

these circumstances, as well as by the strata and the spheroidal 
form of the earth, on these phenomena. 

requested by the British Association ? and I conceive that, in Siberia, Sweden, 
and other countries, there might be found willing coadjutors in the prosecution 
of such an investigation so interesting to science. In this Report I have con- 
fined myself to my own observations, or those which have been made for me ; 
but I find, on looking over several series of results published by other indi- 
viduals, that they tend, more or less, to confirm the conclusions at which I 
have arrived ; — that the subterranean temperature does not increase so rapidly 
in descending, at great depths, as at smaller ones ; and it is remarkable, that 
the observations made long ago, in some mines of Germany, etc., indicate a 
temperature I think 50 per cent, less in the aggregate than the average of 
the results obtained in the Cornish mines, as far as I am acquainted with 
them. 



321 



Report on the Observations recorded during the Years 1837, 
1838, 1839, and 1840, by the Self-registering Anemometer 
erected at the Philosophical Institution, Birtningham. By 

A. FOLLETT OSLER, Esq. 

The records of the Self-registering Anemometer, erected at the 
Philosophical Institution at Birmingham, are now tabulated for 
aneriod of upwards of four years; and though the observa- 
tions from a single station can neither possess the interest nor 
value of those we may hope to derive at no distant period from 
several, yet so little is at present known respecting the laws of 
the aerial currents in this latitude, that I have ventured to bring 
forward the few facts at pi-esent collected. 

The plan adopted first suggested itself in consequence of my 
friend Mr. Snow Harris having requested me to take out the 
mean hourly force of the wind without reference to its direction, 
which he apprehended might show some connection between 
the wind's movements and the horary oscillations of the baro- 
meter*. Considering that this mode of examining the anemo- 
metrical records might exhibit other results equally deserving 
investigation, I pursued the inquiry in the manner set forth in 
this paper. 

The observations are comprised in the years 1837, 1838, 
1839, and 1840. The usual plan is adopted of regarding De- 
cember, January and February as the winter quarter ; March, 
April and May the spring; June, July and August the sum- 
mer ; and September, October and November the autumn. 

Having procured a number of sheets of paper, ruled simi- 
larly to Table I., I commence with December 1, 1836, and 
note down the mean force and direction of the wind during 
each hour of the day, as recorded by the anemometer. The 
figures express, in pounds avoirdupois, the force exerted by the 
wind on a surface of one foot square, kept at right angles to 
the current. I have not noticed the force when less than half a 
pound is registered, it being difficult to read oif a smaller 
amount with accuracy ; and in heavy gales it is not possible to 
ascertain the mean force of the wind even so nearly as this. 
Owing to the oscillations of the vane, it is sometimes difficult to 
ascertain precisely the mean direction ; besides which, the 
instrument occasionally indicates an intermediate place between 

* Second Report of the British Association, p. 233. 
1840. Y 



322 REPORT — 1840. 

two points of the compass ; it is therefore not always prac- 
ticable to attain exact accuracy ; in all such doubtful cases, I 
have taken that which, on the whole, appears to be the nearest 
point. 

It must be borne in mind, that it is the force and direction 
of the wind that this instrument records, and not velocity, 
which the valuable and ingenious instrument invented by Pro- 
fessor Whewell is intended to register. 

But though the oscillations of the vane offer a difficulty for 
the reason just stated, yet it affords a remarkable distinction 
between different winds, and even between the same wind at 
different times. During a north wind, for instance, the vane is 
generally steady, while during a N.E. and E.NE. wind the 
oscillation is frequently considerable. A south wind, too, is some- 
times very steady, and at other times the reverse ; but not hav- 
ing had time to investigate this peculiarity, I merely mention it 
for the purpose of inviting attention to the circumstance ; as a 
knowledge of the cause that produces this diffei-ence, if fully un- 
derstood, may prove valuable to the meteorologist. 

A sheet on the plan of Table I. having been drawn out for 
every month during the four years, I proceeded by taking an 
abstract of each month as shown in Table II., and thus ob- 
tained the total of the forces of each wind for the twenty-four 
hours during the month. 

Plate III. fig. 1 is a diagram drawn from the general totals 
(marked f) in Table III., showing at one view the direction and 
sum of the forces of the wind for each hour of the day, as re- 
gistered at Birmingham, during the years 1837-8-9-40. 

Plate IV. represents the comparative direction and forces of 
each wind during the twenty-four hours, distinguishing the 
quarters of the year. See Table IV. 

Plate V. contains diagrams, showing the comparative force 
and direction of each wind, obtained from the sum of the hourly 
means in Table III. (marked X)- See also Table VI. 

Plate I. fig, 2 is projected from Table V., and exhibits the 
comparative force of the wind for each of the twentj^-four hours, 
direction not being regarded. In this Plate the coincidence 
between the curve of force and of temperature is very remark- 
able, the temperature preceding the rise of the wind by a short 
interval. 

The whole of these tables must be regarded merely as com- 
parative ; I have therefore not considered it necessary or de- 
sirable to reduce the total amounts to obtain the mean force 
per day or per hour, as it would merely add to the labour and 
sources of error without effecting any equivalent practical 



ON THE SELF-REGISTERING ANEMOMETER. 323 

good. Had the anemometer been placed in a more exposed 
situation, we should have had the same comparative results, 
but they would probably have been more clearly developed. 
The principal thing to be aimed at in the selection of a site for 
such an instrument is, to have it equally exposed to all winds : 
whether it be on a hill or a plain, is of trifling importance, pro- 
vided it is not sheltered on either side*. 

There are many other facts which I had hoped to have adverted 
to, such as the law of succession, the mean duration of each 
wind, and the connection of the currents with the alterations in 
the state of the barometer, thermometer, and hygrometer, all 
of which must necessarily furnish interesting subjects for in- 
vestigation, though I have as yet been unable to devote to them 
a requisite portion of my time. 

* The anemometer from which these observations are taken being placed in 
the centre of a large town, does not afford such accurate results as would be 
obtained from an instrument situated beyond the reach of disturbing causes. 



y 2 



324 



REPORT — 1840. 



Pi 


<N 


^-H 




^-* 


^- 


^5.* 


|5. 


^ 

g^" 


^-p 


S-c 




1., 




= 




|™ 


gS 




^o^ 


1 Ji" ^!0 


^-^ 




1- 


© 




co(M 


^co 


^ -CI 


&M 


1" 


^^^ 


^-«. 








CI 




§Si 


^i^r i 


^r? 


1"' 


^ CO 


g^« 




g: 




^ g:r 


cc 


^-'^ 




^« ^- 






^^ 


^-H 


^- 




i^ 


I*' 


t^ 


1- 


,l. 


^« 


^5." 


^ ^ 


1^, 




^- 


^- 


-. >-c |m I®' 


(S 




^ gS" 


^« 




^;f 


M fe- 


' ^« 


^Cl 


S- 


■> 5: - 


|« Is-, 


in 


&" 


- §« 


^-^ |sf 


^.r 


E:^ ^^ 


^s* 








•* 




^« 


^« Is^" 


^^ 1- 


"" " ci 


^C-) 






U t- 


OS 


a •- 


IS- 






^sr g- 


?^ 


^oq 


^- 


»- 


" g=^ 


(N 


C r- 


g« 




^^ 


g« 


h 


g 1* 


?« c- 


S S" ^ "■'" 


^ 




■> I'c? 


1^ 


1-^ 


^^ &;*• 1^ 


&^ 


^;r^-- «-!«^(N 


< 


(N 




- U" 


SCO &■* 


^^ g-- gcO 


P^ 


^::? ^-' 


c g;:*- 


- 


^^ 


|m 




? -^ 


&:?■ 


s " 




1*, 


^-0, ^__ 


- 


li" 


© 


g-^ 


" |s^ 




^^ 


^^ 


1- 


1^ 




.-1- 


-O' g-H 


OS 




^9^ 


^zt 


^5- 


^^ 


- I*' 


g„:c 


^-«* ^;:r i;:r I- 


oc 




g« 


> 


^<N 


i"'^ »*' 


g-;- 




^ rH 


^i-T 


»-. 




I*' 




^:^ g-ic- |<N 


|« 




^- 


g_ 


to 




gHc. 






^ 


I;*- 


&<N 


^■^ 


■, &- 




S- 


in 




m""" 






1" 


|e« 


g- 


-■ ^;r 


1- 


•* 




g„ 


l. 


I" 


' 


|« 


|m 




^- 


^ -:« 


^''^ 


CO 




|„ 






^ 1" 




^-K 






1- 


(M 




|-^ 








lo, 


^-1. 






i- 


- 




%-" 




&-' 


- ^^ 


- |« 


g-J. 


^^ 


■> S3 -: 




& ... ■ 


1 




1 

5 


f 


-* 


IT 


cc 


t-. 


oc 


o- 


C 


^ (M 


rs ' 































ON THE SELF-REGISTERING ANEMOMETER. 



325 



' 


g„ 






Id 


is 
a 






a CO a (M 


4) _ 

a '^ 


a-^ 


' 


E-^ 


h 






a (N c (M 


a»' 


« ^ « -Is 

a** a(N 


a '^ 


« : 

a -Is 

a : 




M "I" 


&:-^ 


l-ic 




1^ : 




2=^ S5i°" 


C i-c 


« : 

a -IS 

a : 


' ^-^ 


I-" 


^-ic 


g-^ 




i 


a (N 


§C0 §« 


a^-H 


a) : 

a -Is : 
a : 


• f:-^ 


1- 


r^ 


1-^ 


: ^- 
■ c . 

: s 


" g a 


§8, 


« -_ QJ -Is 

a« aco 


a " 

4) 


a -IS a -^ 
a c 


^-^ 


I^J 


^-:=. 


t-^ 




, |-|c. |-|« 


a »i 


go, gos 


gHs 
4) 


a : 
a -^ ; 




^ -'^ 


^-^ 


Si" 


= S^ ^-^ 1- 

: s-" g- g- 


« -Is 
a — 


CD p^ <U -^ 

a** a^ 


a iM 


a-^ 


I- 


^ -'^ 


|. 


^ -^ 


a - 
e 


^ a" 


a '^ 


aj a 


a;r 




6- 


gHf 




1^ 


^ 1 


lei C rt 

a 


a —I 

a 


(U -, O -IS 

a" aco 


a IN 


!u : 

g-,s : 




1^ 


h 


^ -IS 


1- 




-c C 1-1 


a -IS 


S<N gco 


s^ 


a -Is : 
a : 


^ 


^-^ 




g„ 


is 


'l-l- 


g-ls 


0) -Is QJ _„ 

a(M a^ 


s*, 


a> (u : 

g-is g-^ : 


% 

r 






1-^ 




• a - 


ic» e -ici 
a 




s«^ §sr 


§<»^ 


cu 4> « : 

S -^ a -Is a -^ : 
a a 




1"^ 




S "fa 




a- 


^ li" 


a-^ 


i- §«^ 


a** 


s-^ 






1- 


1-^ 


g^ 


I-, 


^-!« 


: a Ht) 


a " 


|(M gco 


« -Is 

aiN 


g-ls 






^ 


|-H|« 


g'^ 


1- •■ 


^ -JtJ 


: a -Is 


a -H 

a 


(U CD 

a (M a CO 
a V 


S<N 


a "^ 












1^ : 






a rt 

a 


a -is 




s« 


a 






^-t 


g-lf 




g^ : 


IS 

C -1 




• c 


a "^ 


a-H §-1- 
a g^ 


s«, 


a -Is 








1"^ 




^- : 






a ■" 


a — 


i- i^ 


S*' 


a « 


a -IS : 


^- 


g-^ 


^1S 


1"^ ; 






a rt 
a 


a -H 




s;r 


§- 






%^ 




^ ir 


l-i" i 








a i" 




S(N 


a "^ 






^- 


^-^ 
^ 


i- 










^-^ 


a ^ 
a 


§- Sco 


a*' 


a ^ 






^(N 


i- 












^-H 


<u _ 

a '"' 


i:r ssr 


S(N 


a> -is 

a p-i 






^« 


g.,. 
& 










^ , 

a -1 
a 


^ I*' 


a-|f 
a '^ 


i- aM 


« -Is 

a(>^ 


Soq : 






^ -!« 




grt 






is 

»-l. 


1^ 


ai=' 


S -B O -Is 

S-' aco 


gc, 


a ; 






to 


t>. 


QO 


03 


O 


(N 


5-J 


CO 


Si 


lO CD 




CO oj 


o 


rt " 



326 



REPORT 1840. 



Eh 



n 



0^ 


<N 


.-!='*>. . . 


: ; »^ -H O CO (N --^ 


- 


. -|c< -^ . 


. . ; ifl CO «>• in *» 


© 


; IM lis -H 


; in CO ■* © ffi : ^ 


OS 


. -Isi -|e> 

OO i-c ; 


. . : CO to : «> rt : CO 


CO 


; -H OO -^ 


. -'f -c -l» 
. . ; CO ■>* CO in i-i : ■* 


»^ 


. -^ -^ -^ . 


-Hftj .-te» "-^ 

; ; ; ; t^ -^ CO !C >^ IN IM 


w 


: OO in : 


-1« -^ -^^ -^ 
. . . «0 t-. -* -"SI (M IN 


m 




ph|C» .Mid .-<|« FH^ 

. . . ; OS CO (N ■»* ff« IM 


■^ 


: -H in *5 ; 


: : : | in t>. j ei to »> ©^ 


CO 


1 rt t^ : : 


■; : : : rt oc "' © CO ^ .-< 


(M 


-:c _,. -^ . 1 


; r-< Oi : ; 


; • ■ rt CO -* © 00 : >— 


- 


: rt OO \ \ 


. -^ . --f -=1 -w _ . -It" 
... ; C5 1-1 in © : 




(M 




. -P» -W .Hie* , H« 

. . -H CO -- to in : "^ 


S 




; ^ in »» CO CO rt : -H 


© 


"'" (N CO : : 


-!=< -*s -p 

; : 01 -^ in in ^ -* : ■-' 


C5 


CO CO "^ * 


. -Iw . -1** He) -!e» 

: : -• : to ->*«>. -h - ; 


00 


— »» 1.-5 


. -^ -;«" -i«" . -!« 
.... 00 in •'t : 


w 


HlO 

-H CO (M in : 


-In -le< . . -^ 

: : : -. -* -^ m <m ; : 


tc 


-H (M CO ■* : 


: : ; iM «>. in CO : ^ 


in 


i -H CO CO \ 


: : : : (n Si co ■* j : -^ 


•* 


; *i CO CO ; 


j ■ 1 t>. Tji m CO : : "-^ 


CO 


. rt OO : 


. -151 -Je» -'^ -15" . -^ 

. ; in iM cs CO '- : --i 


■>> 


„^ 


-w -';i 


• CO »>» • 


: : to iM CO 91 -H »i IN 


. 1 


- 






• CO 50 • 


• m CO ^ in CI iM 


1 






N. 

N.N.E. 

N.E. 

E.N.E. 

E. 


E.S.E. 
S.E. 
S.S.E. 

S. 
S.S.W. 

s.w. 

w.s.w. 

w. 

W.N.W. 

N.W. 
N.N.W. 



ON THE SELF-REGISTERING ANEMOMETER. 



327 



feu 
« a; 



n o 






o ts 



01 


^^ 






•!-> 


Ic p 




.J3 U 






o 


;3 fi 




be 0) 


B 


.2^ 


:i 


■^ -l^ 


ta 


•iJi ^. 


(U 


n3 a. 


d 




4^ 


O cS 




-rr s 


tj: 


— . '^ 



CO 5 





1 




-la 
«>. 

O 

++ 


to O IN 


§ 
a 


in CO 


OS 
++ 


-^ -IN 

00 CO -H 


CO 


in 








*» 




CO 


\ W CO 


O 


-In . . 


«|N 






-* 






s 


-ISI -^ -.[IS 


to 


rt 00-^ 


2 






: : *> 


-IN 

IN 


(N 
<N 






o 


; *^ CO 




-W-JN 

— OS CO 


^ 


"'" : : 


-|N 


. . -|N 

: : *' 


S^' 


-l5t 

5^ 


> 




a, 

CD 


•COCO 


to 


-In -IN 
CO OS CO 


to 






: .-i" 


-In 






:-Heo 


-In 


-IN 




-^s . . 


-^ 


.-b> 


-|N 

IN -^ 

CO 


c 




b. 


. 05 


■* 


-^ -fci -In 
^ 00 »>. 


-fel 
© 

IN 


-|N . . 


-JN 


:-^rt 


in 


© 

CO 


> 




to 


; -H CO 


-In 


-In -^ 
CO co-^ 


(N 


-IN . . 


-^ 


ico-^ 


-In 
CO 


OS 
<N 


pi 




«5 


I ■* ■* 


00 


in Its ifs 


in 
<N 


. -^ . 


-»M 


. -IN . 

: (^ : 


-tN 

IN 


-|N 

to 

CO 


1 




■^ 




H^ 


in to t- 


Oi 
(N 


:- ; 


- 


;- ; 


- 


-In 
(N 






CO 


; tOi-H 


CO 


-)N 

CO CO 05 


-IN 

in 

<N 


. -In . 


->N 


-tN . . 


^ 


in 

CO 






«q 


: to ■* 


© 


-^ -In 
■'j' 5^ -H 


00 


-In . 


-|N 


-^ . -W 


(N 


-In 
5 


> 




- 


: to CO 


05 


«»«>.?» 


-In 
<N 


. -In . 


-|N 


rt : "'^ 


-^ 


-In 
05 


1 






(N 


f-H CO 






IN 
(N 


. -^ . 


-^ 


-IN-^ 

CO 


■* 


CO 


In 

-a 

c 
« 




= 




■^ 


*^05 IC 


IN 






- ;- 


IN 


IN 




O 


-if^^ 


-In 
(M 


-In 

■* OS in 


-JN 

00 






-tN-^ . 


- 


(N 
(N 


1 

s 

OS 




OS 


-^-.JS . 


- 


-In -In 
iM rt to 


© 

<N 


. . -In 


-|N 






-In 




CO 


-1« 


-^ 


. -In -In 
; to -"J" 


m 


- ; ! 


- 






-IN 

CO 


« 




w 


H^ 


-lo 


. -IN 

; -^ CO 


K" 


-^ . . 


->M 






-In 
© 






to 


- i : 


- 


. -|N-|N 

: (N-H 


-<i' 


-^ . . 


-IN 






->N 

in 


_; 




W5 


-is-^ . 


IN 




-In 












bo 

to 




■^ 






. ©q to 


00 










00 


i 




M 


. -IM 


-In 


[ -^ in 


to 










-]N 






(N 


. -ts-^ 


(N 


: in -^ 


OS 










- 






- 


. -IN 


-W 


. -In 
. to 1(5 


-In 










CO 






^ 






* 

March .. 
April ... 
May ... 


* 


June ... 
July ... 
August . 


* 




* r 

^ 







32S 



REPORT — 1840. 



< 



3; H 



"5 

f2 


(N ■» 
-^ CO ■* 


«£ 
++ 


© ■* 
to CO cc 


© 
++ 


S © (M 


cc 
++ 


©(Nt^ 

(N -^ 


C5 

to 
++ 


© 
t= 


§■ 

p^ 


(M 


— ; 


(N 


CO 00 


;:^ 






; ;- 


;r 


in 


:: 


-ici -^ -10 


CO 


-=-| 


in 






; ;- 


-lo 


-In 


© 


CO"" 




-^(NOl 


IN 






: : *> 


(N 


QO 


OS 


«p 


Ho 


— « CO 


10 






: : '^ 


to 


IN 


CO 


r-^ ^^1 


(N 


(N (M -< 


in 


-:=' . ; 


".:■ 


; ;- 


^ 


Oi 


«>. 


-)'>-'■' . 


- 


5j — CO 


to 






; ;- 


i" 





to 


— M ; 


CO 


(M *1 10 


f 






r"*' 


(N 


to 

IN 


Ifl 


Mid -■>:) 


•^ 


a^ -* -H 
(N 


30 


-»s . HfS 


- 


. 'ifii-tH 


(N 


in 

eo 


^ 


-^ 


eo' 


10 (M cc 


in 
(N 


. 




:-^;r 


10 


-* 
eo 


CO 


-.1 ITS U5 


^ 


l« CO >-o 




: : "" 


-,:> 


; coSi 






<N 


-N ITS -5(1 


- 


to ^ ^' 


■N 
(N 


; ; - 


~ 


: IN -# 


to 


© 


- 


-< CO -«*" 


oc 


-10 

cc IM ». 


IN 


- ; 


- 


; CO -* 


«->. 




< 


<N 


(N «q -fli 


05 


t^ S CO 


5< 


-^ . . 


-ic 




cc 


© 

'SI 


= 


»» ""^'co 


to 


CO eo eo 


cs 






\ CO S 


^ 


g 





(M eo 




W! to -^ 


5^ 






1 5) CO 


10 


to 
eo 


05 




"5 


CO CO e^ 


-In 
CC 






;-- 


CO 


to 

(N 


00 




eo' 


r-^ -:« -!d 

-Hin© 


-^1 


- ; ; 


- ;'" ; 


-'=' 


-'d 
iM 


t^ 


05 ;<-H 


■^ 


"■''05'^' 


10 


"'" : : 


-■' 






© 
IN 


«£ 




-* 


' a^ N 


^' 


- ; 


- 




S3 


10 


- -'■;;■ 


eo 


" " 5^ -O 


a5 


"" ; : 


-*■■' 


: : '"' 


-P 


oi 


-* 


IN ""'(N 


^ 


""■ (M to 


5b 






: : 5^ 


oq 


in 


eo 


-id 


CO 




to 






: : "■" 


-:d 


© 


<?! 


-IS 

CO « 


to 


'-< M t^ 


© 


-^ . . 


-■'' 


. -'?' 


-;d 


cc 


- 


CO ^ 


>n 


1 _:<.,-,« 
1 -" 


05 


'^^ . . 


-;». 


; ;- 


- 


■n 


n 




""g-3 


* 




* 


: : ; * : : : 




-K 



- Ph 



ON THE SELF-BEGISTERING ANEMOMETER. 



329 



- > 



^ > 



i 


-JM -^ -^ 
© ■* t^ 
-* ITS 




CO © © 


CO 
<M 


^^:z 


to 


CO in -^ 


en 

++ 


-pi 
«>» 

in 
m 


Pi 


<N 




OS 


-^-1« 


CO 


I :- 


- 


. -is -is 


- 


-pi 


- 


m — e< 


00 


-^^-^ 


CO 


. . -^ 


-Is 


:(M 


ST 


-Is 


© 


in CO 


05 




-* 


-^ -Is -]s 


Si 


. . -IS 


-is 


to 


Cl 


00 CO 


(^^ 


-H -* <M 


-Is 


-Js . -is 


<N 


i-'-o, 


-fa 
(M 


S 


CO 


CO CO 


(>» 




to 


-^-p»-|s 


-Is 
(M 


. His 

. CO 


-Is 
CO 


^ 


«>. 


Ho -Is 
Wrt CO 


(M 


(N -^t to 


(M 


-Is . 


Si 


: : ^ 


■5fi 


M 


!0 


00 1 CO 


^ 


-IS 


-Is 

to 


-p> . 


-IS 

(M 


: : "* 


-pi 


-is 
CO 


»C 


lo i -^ 


OS 


-|5< -Is 

<N «5 to 


■* 


. -IS 

01 : -- 


-IS 

CO 


: :«| 


CO 


-Is 
OS 
(M 


■^ 


to : oi 


-1« 


-is -IS 
-H 00 (M 


<M 

IM 


IM ; (M 


■* 


. -1^ 
: o' 


-p. 
<M 


00 

CO 


M 


ao ; IN 


© 


-is 
iM OS © 


-Is 
IM 


CO : : 


-Is 

CO 


in 


to 


-Is 
5 


(M 


. "pi 

© ;(?> 




-Is -Is 
-^ CO OS 


C5 


-Is . . 

(M : : 


-is 
(M 


-is 

^ (N in 


-is 

00 


s? 


- 


00 •; CO 


- 


-Is -IS 
<N — lO 


OS 


-!«• . . 


-Is 


-^Hs-ls 


-pi 
in 


CO 




(M 


. -Is 
to • -^ 


-i« 
© 


— ©© 


o 

IM 


-Is . -|S 


(M 


"" :^ 


-is 


-pi 
© 


- 


to : — 


-|0) 


-^ -Is -Is 
IM to to 




CO : !M 


U3 


. -Is -Is 

; ^ to 


00 


-is 

to 

CO 


© 


CO -rt 




i-H 00 CO 


-fei 
5^ 


CO : : 


CO 


-IS-JN . 


iM 


-is 
(M 
IM 


05 


CO 1 'M 


"O 


-is 

IM <>«rt 


-Is 
© 


-Is . . 

PS : : 


CO 


I '• Si 


-Is 
IM 


-is 


OO 


»^ : "'' 


Si 


-Pl-^ 


CO 






i i- 


- 


-pi 
to 


>>. 


(M \ CO 


m 


-|s -is 


(M 






; •> 


- 


00 


to 


CO :-^ 


«5 


-Is -^ -Is 


-Is 
CO 






: IN : 


5<l 


© 


>n 


CO i^S" 


^^ 


"^^^ 


-is 






:-- 


IM 


IM 


-* 


CO :-^ 


■* 










. -pi . 


-IS 


© 


05 


00 j (M 


© 


:-Heo 


^ 


- : : 


" 






-is 

in 


(M 


-id . 

*-. : (N 


Oi 


-Is 

-I-H CO 


-Is 


- : i 


- 


. . -Is 


-Is 


-Is 

to 


- 


-lo . -Ic. 

to : -^ 


CO 


-^-is . 


- 


- : : 


- 


. . -Is 


-Is 


-Is 

© 








* 




* 


June ... 
July ... 

August . 


* 




* 


g3 
OS 



330 



REPORT 1840. 



n 



"a 
1 


-* 00 5D 




i-< -^ <o 

t>.-^ CO 


91 

<N 


os" 91 ^ 

^ CO 


It? 


© — CO 
— CD© 


05 


05 
"5 
>t5 




(M 


: o' 


CO 


">=> . . 


-to> 


-id 
(N : 


91 


: — 91 


CO 


05 


- 




-let 


. -ts 


-;«i 


-to» -,^ 


91 


;-- 


-to. 
91 


-Id 
© 


© 


Si Si ': 


lO 


-l«-}5i 


CO 


: ;- 


- 


;-- 


ST 


-'to. 


OS 


Si T)i CO 


05 


-IS 


CO 


i-- 


91 


-to" 


-to. 


»>. 


CO 


CO CO Si 


5b 


— : 


IM 


. -to^-toi 


91 


r"- 


-to. 


-'J' 


!>. 


(N — CO 


w 


-^ -;«] -to* 


■^ 


i(n "'^ 


Si 


: — 91 


CO 


-to. 


«3 


IM rt 1^ 


». 


(N -< : 


-* 


;-^(N 


CO 


-Id-W 
<M9I 


i« 


05 


ITS 


-[n -B) -In 
■* <M rH 


-Us 

cc 


-to) 

-■* COIM 


OS 


. -If 


-to« 
91 


-id -'d -to« 
i-c 91 ■* 


-to" 

CO 


oa 
91 


'^ 


(M CO^ 


«>. 


-to< 
00 <N (N 


Si 


-to»-to» 


CO 


— CO 00 


CO 


-to. 
m 

CO 


CO 


1 CO ©» 


s 


«>. ; CO 


o 


: "* 


lO 


-qi in 


© 


-to. 


95 


: CO CO 


I>» 


-toi . 

CO ; «>. 


to 


rt : CO 


■* 


-to. -to. 


91 


00 
CO 


- 


FH (M ^ 


-^ 


CO -H Its 


^ 


. -to. 

91 : 91 


^ 


. -to. -to. 
; 00 in 


■"* 


-to. 

CO 




IN 


r-^ Of 


"* 


50 1 05 


05 


91 \ ST 


^ 


— l>»lfS 


-* 


-to" 
91 

CO 


S 


"'"mJo 


o 


-to< . -toi 


© 


: : Si 


Si 


— »>. to 


-to. 


CO 


O 


CO (N ». 


(N 


CD ; -H 


-to< 


: :co 


CO 


-to. -to. -'to. 

r- in 05 


-to. 

to 


-Id 
05 
CO 


05 


I CO lO 


00 


S» 1 Si 


U5 


: :=* 


CO 


-< -* to 


^ 


91 


OO 


if5 CO CO 


- 


(^^^(^^ 


m 


. . -to! 

: : ">« 


91 


\ CO Sd 


-». 


© 

CO 


«>. 


ifl CO rt 


o 


-^S-IS-IN 


-Bl 
CO 


. . -i« 


-^ 


-to> 


-Id 

o? 


-Id 

CO 
91 


<o 


■* CO to 


CO 


. -if . 


-to. 


. . -to' 


-Id 


: : '^ 


«>. 


91 


lO 


co?c -^ 


■* 






: ;- 




: : "^ 


>o 


© 
91 


■^ 


CO «o-* 


CO 






-;« . . 


-to" 


: : "^ 


-* 


00 


CO 


; t^Si 


3j 






-:« . . 


-Id 


. . -Id 
: : w 


-to. 
CO 


-Id 
CO 


<>, 


; ?i(M 


Si 






'■°' : : 


-to! 


: :«> 


CO 


CO 


- 


: **^ 


35 






-to. 

91 ; 


Si 


. . -^ 


-to" 


-to. 
91 


n 




all 








sag 








c3 

OH 



1 



ON THE SELF-REGISTERING ANEMOMETER. 



331 




332 



REPORT 1840. 



cq 





1 


frotO 00 
i-H rl O 




iirs t^(£ 


00 


O CO 00 




O 8^ t>. 


IN 


© 






2 


: : N 


(M 


r^lCH 


- 


<N : 


eo 






»>. 




" 


: : (N 


<N 


: : iM 


IN 


: 0^ : 


-Id 
IN 


; :- 


- 


t^ 




o 


; ;- 


- 


:^ : 


"" 


^'"^ . . 


M^ 


. "^ 


-p 


CO 




05 


. "^ 


-IjCl 


1 -ts 
t — WS 


to 


^ IN : 


-|M 
CO 


. . ''" 


-^ 


en 




00 


. ""^ 


^ 


: : in 


UO 


r^ . . 


-^1 


. "^ 


-^ 


00 




b» 


. '"*" 


Hc. 




b» 


«o : : 


to 


-hn 


(N 






to 


: 5i ^ 


-* 


:coir5 


00 


"5 : : 




: : M 


CO 


IN 




lO 


p- -^ «o 


00 


-^ 


IN 


«5 : : 


m : : 


-^ 


»>. 




•<# 


— ^ 00 


- 


:-Hco 


■^ 


•* : : 


Ti" 


IN : Si 


-151 


© 
CO 




CO 


<- — 00 


© 


--- 


CO 


■* -< : 


■c 


: CO 


CO 


IN 

IN 




(N 


-1« 




o 


-»S -»! -Bi 
CO-Hr- 


-Id 
so 


22 


CO 


© 




- 


: <M C5 


- 


— : CO 


'I' 


CO (N rt 


t^ 


-H : CO 


C5 


W 




<5 


2 


— -H ?0 


00 


IN (M (M 


(O 


CO IN (N 


-fc) 


-< : 00 


Ol 


CO 




- 


<M '-f CI 


»» 


: — (N 


•* 


-|n 


uo 


" : "5 


-ft) 
?o 


00 
<N 




o 


W (>» So 


!» 


: ^ i>\ 


CO 


^'iN ^" 


>« 


: ' ■* 


o 


-Id 




05 




<o 


: <M : 


■N 


IN ^ : 


CO 


: : 00 


00 


05 




CC 


: — CO 


■^ 


[^ ; 


^ 


^' : ; 


;i' 


: : IN 


©^ 


CS 




t^ 


: ^ >o 


i 


;" : 


-Id 


(N 00 : 


o 


: : -^ 


■* 


IN 
IN 




«D 


: : ^" 


■<3< 


: 5^ : 


IN 


FH :d : 


«>. 


5i : 00 


© 


S 




in 


: : -^ 


Tjl 








>« 


" : »» 


00 


O. 




-* 


: CO 


■* 






CO : 


CO 


: : 00 


-Id 
00 


to 




M 


^ : CO 


■<* 


]-' ; 


-" 


: IN : 


IN 


: : «5 


in 


on 




IM 




SJ" 


: :r"''°' 


»1 


:eo : 


CO 


-It) 
: "5 


-!d 

>n 


CO 




- 


ff» : r-. 


CO 


: IN '-' 


CO 


IN : 


CO 


: : IN 


IN 


IN 




H 

n 
H 






March.. 
April .. 
May . . 




June ... 
July .... 
Aug. ... 




OH 



ON THE SELF-REGISTKRING ANEMOMETER. 



333 



2 
o 


cc to t» 




-« t^ F- 

■* f" <M 




•^ C5 : 
IN ■* ■ 


CO 


-fn -^1 -Bi 

«>. in o 
(N -<* «>» 


-m 

CO 


s 

« 




(N 


« ^ -* 


« 




sz 






i(NOO 


© 


(N 


::; 


■* irj (N 


(M 


-p-jc. . 


<N 






. -|e<-;i» 
; m CO 


OS 


CO 
IN 


o 


00 t^-* 


OS 


^-^ 


CO 


: ** : 


»l 




in 


-in 
CS 
(N 


cs 


tOlO M 


in 


- ! 


- 


- ; : 


-JS 


: "* : 


-IN 
-* 


IN 


CO 


US to-* 




. . -K» 


-;» 


0-1 CO ': 


in 


'^ : 


-|0 

in 


(N 


(-. 


-* -* CO 


H?i 


- i 


- 


: ■* : 


Tfi 


^ CO "' 


ft 


^ 


«c 


in 5<) <M 


C5 


^1-^ . 


Si 






CO <N 


to 




lO 


5i sq (M 


to 


- : ; 


- 






-Id -Is 
rt IN(N 


to 


CO 


■* 


CO N (N 


tC 


Ho -lo< 


CO 


-fti . 


-fe) 


1 CO 00 


^ 


CO 
!N 


« 




CO 




o 


(N to : 


05 


-^1 -|?i -fr* 
i— IN IN 


to 


CO 


<M 


■* "» 0<« 


r^ 


eo-« : 


-Id 
•* 


"^oo ; 


00 


-|e)-i« 

in ■<* 


e 


■* 
CO 


- 




■* 


Til ^ rt 


to 


(N in : 


!>. 


iflIN •* 


- 


00 
CO 


t 


<N 


■* l-H -* 


05 


-In -Hi 
CO 9q 


to 


(M CO 


-IS 

in 


-in 

IN -- CO 


to 


(N 


=:: 


,— Tf ■* 




m ^ Tji 


- 


IN IN : 


m 


-fc< -Is -^ 
IN — t^ 


-Ha 


CO 


o 


M CO ITS 


<N 


-i« -i« -t« 

CO 




-Ha . 
IN-H . 


CO 


M in 


to 


to 

IN 


C5 


(M (N ■* 


CS 


-;« F-^ -|C1 


CO 


(N -"SI 1 


to 


-Hi -Is 


CO 


(N 


00 


r^ CO CO 




-Is H5< 


TJl 


<N OS ; 


-In 


; i- 


- 


m 

IN 


t". 










^ : : 


-fe) 


(N :-^ 


CO 


© 


to 


-!« «!« r-|« 

(M — — 


>n 






- ; 


- 


: ;- 


- 


-In 


»o 


CO -^ N 


to 


|lN-H 


CO 


- ; 


- 


. . -In 


;? 


-»a 


■* 


(N ; Si 


-^ 


: "^ " 


co' 






"" i- 


-^s 


-In 
OS 


w 


*i : CO 


lb 


*» : : 


IN 






■: ;- 


- 


00 


(N 


CO : CO 


to 


IN : : 


IN 






-jN . -m 


- 


OS 


- 


^ : CO 


-^ 
Tr 


IM : : 


e« 






' . -te) 
-^ ;IN 


CO 


© 


H 
W 




^ i 4 








1-5 HT«! 




III 




c 2 
OH 



334 



REPORT 1840. 



o 

T 

Oi 

I 

CO 

I 



to 
< 





O ■<* -H 

O CO to 


CO 


■w © m 

lO CO-* 


© 

CO 


-Id 

— 35 CO 

OS © to 


CO 

IN 


to cc us 

to to ■* 

IN 


OS 
05 


00 
us 


§ 

oi 


IM 


©■*«>. 




-p-p 


CO 


-td 
us : IN 


-Id 


: — t* 


00 


© 


- 


^ i-( !>. 


© 


-H w : 


CO 


to : CO 


© 


-W -!d 

: CO 


■«JI 


CO 


© 


«>. IM CO 


CO 


'^ IN : 


CO 


-td 
«5 : IN 


-Id 


-|d-ts 
(N « 


IN 


-Id 
us 
CO 


CS 


<M ■* O 


to 


<N <M : 


^ 


-Id 
CO :iN 


-Id 
US 


-Id 
CO — 1>. 


-td 




00 


to Z-'o» 


5<« 


Si (M : 


-Id 


-!d-»i 
CO "* 9» 


© 


— Si o 


CO 


us 
us 


»* 


— C^ •* 


00 


-Id 

<M ^ : 


co' 


CO CO <N 


05 


-id-^ 

CO us 


OS 


-'d 

OS 
us 


to 


(M <M ^ 


"i 


CO : (M 




CO — : 


-Id 


■*© 


-Id 


© 

us 


ItJ 


OS « CO 


00 




■* 


>«- : 


to 


N -^00 


us 


-Id 


■^ 


-In 

^ (M ■* 




CO— : 


-* 


toto — 


■* 


■>* rfi t-» 


-Id 
us 
IN 


to 


w 




5^ 


CO '-> 


-Id 


-^ -Id -p 
to to — 


-Id 


-»-^-d 
->* t-.(N 


-Id 
IN 


to 
to 


<M 


-^J -iO r^in 

^ 00 


© 


CO — *» 


- 


-^ -Id -d 
in ■* <N 


Si 


-id -^ 
— US © 


<» 


to 


- 


eo-H to 


© 




« 


-Id 

to CO (N 


-!d 


-Id -Id -Id 
— us 05 


-fei 

to 


us 


< 


(M 


W (M >fl 


(N 




GO 


-|d -Id 
-* — -^tl 


§ 


-Id 

US us 


0^ 


->d 


- 


00 ; to 


■* 


(N : CO 


U5 


U5 « CO 


00 


OS CO © 


CO 
IN 


-»d 
© 
to 


O 


ITS CO "5 


■* 


IN : — 


■* 


-p-|d 
■^ — -* 


S 


cc to — 


US 
Of 


s 


OS 


ifl C-l CO 


© 


■«Si C0*« 


05 


CO— IN 


to 


t>.lN © 


-'d 

OS 


us 


00 


00 1— 1 t-» 


©» 


— — IN 


-^ 


. "*" 


Si 


-d -Id -^ 
US — OS 


to 


us 

CO 


t- 


-id 

1-1 : (» 


ob 


— ■* 


-rd 

to 


-Is 

: <N us 


-Id 


-,^-ld-w 
IN CO 


to 


OS 
IN 


to 


^ : to 


-.^3 

t^ 


(N •* 


«> 


. . to 


to 


-Id -Id 

(N t-. 


© 


© 

00 


Ifl 




05 


to — — 


05 


: : ^ 


us 


S) — CO 


to 


© 


■* 


CO : «>• 


© 


m CO : 


-Id 
00 


: — us 


to 


00 — — 


us 


© 
■* 


OS 


«5 : 05 




-^ 


(N 


-^-co 




-Id 
ININ^ 


-Id 
to 


00 
CO 


(N 


-lo M|0 -KK 
US © 


w 


-p-^-ls 


-te) 
CO 


-p 


-Id 


-p-!d 
— Tf© 


to 


-Id 
to 

00 


- 


lis -H — 




-Id 


-p 


-^ -id 
"* : 


us 


--- 


CO 


00 


n 
n 




<5|l 








1-9 "-S^J 








d1 
OH 



ON THE SELF-REGISTRRING ANEMOMETER. 



335 



J, 


Its©*? 


to 


033!© 
w© 0. 


-]C1 

CO 
Its 

IN 


© Its «>. 
-H CO »-H 


CO 
IM 

to 


©"cO © 

to©© 


CO 
Its 


© 

IM 




(N 


!0 — CO 


to 


: *" 


CO 


to ©*^ 


-Id 
CO 

IM 


-Id -Id 

— CO© 


■* 


-Id 
© 
© 


- 


M 05 -H 


-i|o 

§5 


: : <N 


(N 


-Id -l« -10 
Its t». to 


OS 


-Id -Id -Id 

IM Its 00 


-Id 
© 


-Id 
© 


O 


CO CO CO 


§ 


: :-' 


- 


*.«%^ 


s 


-Id -Id 

to IM © 


00 


t^ 


05 


(M to OS 




: CO IN 


Its 


-l« -[CT 
Its IM <M 


i 


IM CO © 


Its 


-Id 
*-» 
Its 


CO 


.-H lis ItJ 


2 


: 1* CO 


-It) 


»>OS IM 


CO 


IM eoiM 


t* 


■Jta 
Its 


t^ 


ifl ?o to 


CO 


-|o 

: ■* (N 


-0 
to 


-Itj 
© to CO 


-Id 
© 


■* -^ Its 


CO 


Its 


w 


-HI -^ OS 


CO 


:t^<M 


-[CI 

OS 


OS © 00 


IM 


Its : © 


■* 


© 
© 


in 


Its CO 


^ 


CO CO 


IM 


-l« 
© t^co 


-Id 
CO 


tOlM IM 
— IM 


© 


-Id 
© 


■* 


«5 CO (M 


to 


--co 


-Id 


-|51 

© CO © 


-pi 
CO 


-Id -Id 
»>. -^ © 


IM 


© 
© 


CO 


U5 CO t-. 


(M 


^ p-H>. 


OS 


-* © Its 


-Id 
00 


-Id -Id -Id 
CO -^co 


-Id 


Its 


1-1 oi m 


to 


CO© Its 


OS 


-* CO -^ 

rt S^ — 1 


9^ 

Its 


-Id 

© pH OS 


CO 


-Id 
© 

CO 


- 


GO 03 00 


to 


-10 MIM -la 

j^CO^ 


-1« 


CO(M-H 
— IM — 


to 


-Id -Id 

-* to CO 


-* 
CO 


-Id 
© 

Its 


g 
< 


aq 


(M IM OS 

1— CO 


CO 
Its 


r-|« -.|N rH|« 

rt CO -* 


-|e» 
OS 


-^ © ■* 


CO 
CO 


cooo t^ 


?§ 


-td 

CO 


= 


M © CO 
-H eo-H 


Its 
Its 


COWCO 


CO 

<N 


Hw -|ci -|« 
© t^t^ 


-Id 

CO 


-Id -Id -Id 

CO 00 to 


CO 
IM 


-Id 
© 

CO 


o 


© ITS © 

-H (N rt 


to 


CO to to 


Its 


CO CO to 

IM 


CO 


-^ -Id -Id 
(N © to 


Its 
IM 


IM 


<35 


CO © rt 


s? 


-* <M -^ 


s 


"* -H Jo' 

(M 


OD 
IM 


t>.(M «>. 


© 


© 


CO 


CO "-^ OS 


?? 


-|« -|51 

CO CO CO 


Its 


-Is 
(M Its 00 


"IS 
IM 


-Id 

t^ : © 


-Id 
CO 


© 
00 


t* 


b»CO OD 




«>.0^ CO 


IM 


-Id 

r-lpHCO 


-Id 
Its 


Its : © 


■* 


-Id 
© 


!0 


>nt»os 


e3 


t^CO "-1 




'H © IM 


-Id 

CO 


-Id -id 
•^ © 


- 


Its 


OS in (M 




_ rt|C) 


-^ 


-jo 


-Id 
© 


-|d-Ks 


00 


© 


•* 


0.10 OS 


«1 


<M>-irt 


■* 


(M CO (M 


t^ 


-Id 

CO Its r^ 


© 


-Id 

CO 




10 00 t-» 


§ 


toco-^ 


= 


to Its i-H 


<M 


CO Its — 


© 


-td 

(M 

Its 


10 <M to 


^ 


Its CO 


CO 


© t^-* 


*^ 


-Id 

(M ■* CO 


-Id 
© 


-Id 
© 

Its 


- 


CO CO»^ 


OS 


(N « (N 


to 


T* 00 CO 


-Id 

Its 


-^-ld-|d 

rt IM 00 


-Id 
(M 


CO 
Its 


« 


qII 1^-1 1;=^ III 


OJ 

OH 























M6 



REPORT — 1840. 



I 

GO 



n 
< 



1 


-* -* l?1 

O' 3J — ' 

'^^ (M <M 


f. 


OS IN -^ 

1^ rM in 


to 
in 
CO 


-m -ici 
— 1 in -f 
m in 00 

IN ^ r- 


OS 
in 


■rf CO l» 
OS IN -* 
^ <N p-H 


-|n 

m 


-»i 
00 
(N 
(N 


a; 


N 


S'-" (M 


Si 


CO 1-1 -H 


© 


5i' ; -* 


-in 

to 


^ © IN 


-* 


CO 

m 


- 


GO O. to 


5-1 

CO 


00 : ^ 


OS 


-fs -In 


to 




-|n 

m 


CO 


2 


S'oD t^ 




^ — -1 


CO 


-is 
■%(1 rH m 


2 


-»• . 






C-. 


OS tS 153 




in rt r-H 


«>^ 


-In -In 

CO -^ CO 


00 


-ln-|n 
IN IN 


m 


I* 


CO 


05 ^1 00 


s 


-a' o i>j 


fN 


OS <N CO 


OS 


^ o» 5» 


OS 


to 

CO 


t^ 


IM OS 05 


CO 


-in 

ooo 


-151 

00 


•— in oi 


00 


CO CO *i 


00 
(N 


to 

OS 


'O 


-* 30 t^ 




ti© (N 




-In 

f" in OS 


-In 

in 

(N 


-in 
OS©*, 


CO 


IN 


lo 


-H 00 OS 




iM (M in 


OS 
iM 


in OS -i 


to 

CO 


JN CO <N 


■N 
(N 


m 


•* 


(M Os'co 


CO 


00 OS ■<* 


IM 


^'5i CO 


© 


in co^" 


CO 


OS 
(N 


eo 


o: !>. P5 


00 
5^ 


':f t-OO 


cr. 

(N 


OS « ■* 


in 


-ai IN t>. 


CO 


oi 

^ 


(M 


OC 'M «>. 

CO -^ 


S 


^ !0 S 


CO 


Oi to 00 


-* 


CO © ?i 


CO 


m 


- 


IM iM 


CO 

in 


-5)1 to ■* 


in 


i'= 2 


t^ 

-* 


OS ^ to' 


© 
1* 


m 
m 


< 


OJ 




i" 


OS o -* 


CO 


to CO CO 


5^" 

in 


CO m CO 


ft 

CO 


•^ 

■* 


- 


w t^O 


5^ 


in CO ^ 


CO 


(N -* — 
<N — — 1 


00 


ob OS 01 


to 

CO 


-In 

2 


o 


^ICT "!« 


IM 


IN in "-^ 


OS 


-* «>. 8*1 


eo 

eo 


= 2* 




2 


05 


(N GO 00 


00 


»5 ^ IM 


to 


-in 

CO toco 


(N 


OSTJl ■* 




-^ 
£ 


QC 


-" OS QO 


CO 


— CO (M 


« 


<N ^' IN 


2 


-(n-p 
to ■<* CO 


<N 


-m 

IN 


t>. 


T)l -* to 


ni 


^ -* ^ 


t>. 


CO in CO 


t>. 


^p- OS 


■* 


§ 


ra 


(M S in 


To 

CO 


-.p-js . 


CO 


to -^ CO 


CO 


IN '- -^ 


-m 


it 

to 


>o 


STos'Ss 


irs 


-Id -1« 


CO 


-* ^ CO 


(N 


-In -W 
CO -^ OS 


«>. 


m 


■* 


t>. «>. ro 


00 


;-- 


5> 


5i (N -^ 


00 


-In 

■* mm 


-In 


-In 
CO 

m 


n 


00 i-^-* 




-]e» -^ 


©^ 


eo -* 


00 


-* *, t^ 


CO 


(N 

m 


<N 


r-lCl ^\^ 

IN -* "n 


CO 


-;c . -ic 


- 




in 


osm — 


m 

(N 


-m 
to 


- 


OS <M '^ 


to 


-'le^ . . 


-lo 


m : OS 


2 


■^ 00 OS 


!N 


§ 


tn 




• &* ■ 




J2 _ 




June ... 
July ... 
August . 




■is >■ 

£•" o 







ON THK SELF-RKGISI'KRING ANEMOMETER. 



337 



1840. 



e2 


-In 
ITS t-. to 


-Id 

00 


-Id 


-»d 


-Id 

t^to — 

-H — (M 


-Hi 
Its 


-H>-^ 
^ -<JI to 
CO t>. to 

(N -H (N 


(N 

to 


-Hi 

CO 

(N 




2 


Ol •* (M 


to 


toos^ 


to 


C<l (N ITS 


-Id 
© 


-Id 
•<«< (M -H 


-Id 


© 
00 


S 




CO 


tJT© — 


lO 


-Bi -p -^ 
(M — CO 


-HI 


-Id -Id 
t>»(N CO 


CO 
CO 


00 


o 


O (M itj 




-tl-ld-pt 


-p 
■* 


-^-Id-id 
IM ^ to 


-Id 

© 


© Its CO 


CO 

(N 


i 


05 


-* tc S^ 


CO 


STco : 


lO 


-]d -Id 
<M ^ CO 


o. 


-Id 

t-* to lt5 


-Id 

00 
CO 


-Id 

© 


CO 






-Id-tM-^ 
IM (N r-l 


-Id 
to 


-^ -Id 


*^ 


-HI 

CO Its CO 


-Id 

CO 


© 


«>. 


-!C1 -^ «te« 

-H CO ■* 


-fa 
OS 

CO 


-p -Id -Id 


I-. 


rt CO CO 


-HI 

2 


1(5 © Its 


© 

(N 


-Id 
CO 
CO 


to 


to O ^ 


-Id 

CO 


00-^^ 


-Id 

05 


-Id ->M -^ 

Its to 05 


-HI 


-Id 
-* t- t>» 


ST 
©I 


© 


Ifl 


-icfl -let 
CO IC rt 
0^ -H -« 


© 
in 


gC^ 




-|d-w 
to CO © 


i 


-Id 
t^ to Its 


CO 


-Hi 
CO 


■^ 


to'co IM 


to 


-Id -Id -Id 

» CO CO 


CO 
CO 


-ld-^ 
00 © CO 


CO 


CO ^to 


Its 


CO 


CO 


toes CO 


at 


'-< «5 Sq 


CO 
<N 


-HI 

t>. I>» Its 


-H« 
OS 


© Its 00 


IM 

lO 


-Id 
CO 
CO 


<N 


-H CO -< 


-Id 

CO 

to 


-Id -Id 

cs lo -H 


to 


-Hi 
— © t^ 


CO 

CO 


CO -^ © 


to 


© 


- 


-Id -Id 
o ■* ■* 


05 


-Id -Id -HI 
CO t^OJ 


?? 


-Id 
-* .-1 1-. 


-Id 


© ©© 
>-H .-< (M 


-Hi 
© 


-Id 

i 


S' 

< 


(N 


-Id 
coco © 

-H ^ rt 




-^ -Id 


§ 


CO © to 




-HI 
Its 00 «>. 




in 

00 


- 


-Id -fc« 

<M (M© 


to 


-Id -Id 

05 05 IN 


IM 


-^ -id 

toco CO 


00 
CO 


-Id 

CO (N -< 


-Hi 
CO 


Its 
Its 


© 


© CO ^^1 
.- CO rt 


to 

ITS 


-»d-fc. 
1.-5 (-.to 


05 


-Id -Id 

00 rt «>. 


CO 


-|d-H< 
■* 00 -* 




© 

CO 


C5 


— 05 to 
i-i sq 


to 


-^1 -Id 
(N CO lO 


- 


Its ifS to 


-HI 

to 
<N 


-Id -HI 
© Its l>« 


<N 


-Id 

B 


CO 


-Id -Id 
to ■*»» 


CO 


Tt (N <M 


-^ 
<» 


-HI -Id 

© «>.to 




-HI -Id 
t^-* CO 


Its 


© 
© 


o. 


CO lO (M 


U3 


CO to 


05 


to to its 


CO 


CO ». to 


to 


-Hi 


to 


-|d-p 
(N F^ (M 

^ CO 


to 


CO rH nrj 


■* 


in CO ■* 


-Hi 
iM 


« Its CO 


21 


-Id 

CO 


IQ 


-id-kd 

-* 1C3 rt 

rt CO 


m 


-Id -Id 

00 -1 r- 


- 


lO 1 CO 


CO 


-H> 

^ to to 


-Id 

to 


-Hi 

to 

CO 


^ 


-»d -Id -Id 

O.CC CO 
CO 


OS 


-Id . -W 

to : — 


CO 


-Id -Id 

COf— o 


© 


-Id -Id 
CO (M CO 


■5tl 


-Id 

CO 


CO 


-^ -Id -Id 

CO 


-Id 

CO 


to :(N 


-Id 

CO 


-Id 

OS CO CO 


-Id 


-Id 
00 Its i-H 


-Id 


© 


SI 


-Id -Id . 

(N — ■ 

CO ■ 


CO 


-Id -Id -Id 

to <M 


05 


-Id 


-Id 


-Id 

CO CO 


-Id 
to 


-Id 


- 


-*© : 

CO • 


CO 


-Id 
CO t^-^ 


-Id 
05 


-HI -Id -Hi 

CO 00 


-Id 
(N 


©05 \ 


IM 


CO 






: >> : 

o 3 ^' 
tu 5 "3 




caS.ce 




■-si-s-*! 




^6i 







338 



REPORT — 1840. 



< 
Eh 





iO to O) 
CO in —1 

r- CO — 


to 


-Id -Id 
t>.fO CO 
*>.t»OD 


CO 

CO 


-pi -Id 

— <M to 
t-CO OS 


© 


-p« 


-Id 

cs 


-pi 

CO 

us 




(M 




-td 


-Id 


-Id 


;-" : 


" 


i::-" 


2 


■* 


- 


-In 
05 Its lO 


-p 

OS 


-^ -Id 


■* 


-pi -pi 

:o5 


^ 


-pi -pi 
en OS — 


— 


-pi 
© 

us 


© 


00 00 t» 


CO 


-»s -Id 


"5 


_ -pi -pi 


- 


-Id 


-pi 

us 


-pi 

us 


05 


-»1 
m © ■* 


-p 
OS 

IM 


-Id 


-pi 

its 


_ -pi -Id 


- 


-pi -pi 
OS : 


© 


to 


00 


00 00 CO 


© 
CO 


-Id -Id 

CO IM 


to 


-pi 

(M <M 


5 


— CO : 


■>* 


-pi 
Tf 


b» 


to OS ■* 


OS 


-Id 
CO — -* 


-Id 

00 


-p. 
CO CO CO 


-pi 

OS 


-pi -pi 


-<t 


-pi 
us 


CO 


OS f— t 


CO 


ooco ■* 


-Id 

Its 


Its Its Its 


-pi 
«ts 


CO— — 


US 


to 


ifl 


-!« -[e* -^ 
00 CO 


CO 


©I CO t>. 


-Id 


-pi -pi 

I-I !>. t-. 


to 

(M 


-Id -pi -pi 

us (M 


-pi 

CO 


-pi 

OS 
00 


-* 




Its 


OS Tji to 


® 

(M 


CO© «>. 


% 


-pi 

00 to — 


-pi 
us 


© 
OS 


CO 


CO OS to 


-Id 
OS 
©5 


?q ■* Its 


-Id 

IM 


OS (M © 


CO 


-pi -pi 
t>.us to 


OS 


© 


IN 


HP 

CO Ifl to 


-Id 

OS 


-p 

to -qi CO 


-p. 

CO 
<M 


-pi-pi 
00 Its OS 


CO 
CO 


-pl-p)-pl 
to to I* 


CO 


-pi 
eo 

(M 


- 


-fc. -p -le< 
ITS -N ■* 


-p 


-Id 

CO CO -^ 


-fc) 
© 


-Id -id 

CO -* 00 


to 

(M 


© »n CO 


us 
<M 


CO 
OS 


< 


<M 


in to Its 


to 


-Id -^ -^ 


<M 


»- Its ^» 


CO 
<M 


us OS CO 


00 
<M 


OS 

00 


- 


o© to 


to 


(M to 00 


<M 


-pi 

-H 00 


-pi 
OS 


-pl-p) 
Til «>.t^ 


OS 


-pi 


O 


-p -p 

00 00 9^ 


OS 


-p 
CO Its to 


-Id 

<M 


-p)-ld-pl 

»>» 00 


-pi 
to 


-pi 

CO CO ■<* 


© 


® 


Oi 


-p -|« -.|C< 
■^ CO CO 


-Id 


-Id 

— (Mm 


00 


-pl-d 
— -^ Tf 


© 


-pi 


-pi 

OS 


OS 
us 


00 


Its «>. Its 




-Bi 

00 to 00 


-Id 

(M 
iM 


-pi 

!N -"Ji CO 


-pi 

OS 


-Id -Id 
eo CO 


l>» 


to 
to 

-pi 


t>» 


its^M 


IN 
IN 


(M (N to 


© 


CO <M : 


us 


-p< 

CO IM 


-pi 

us 


® 


US -H CO 


OS 


(MCO-H 


to 


-pi -pi 

(M -^ 


t* 


-Id 

: us — 


-pi 
to 


OS 
CO 


W5 


-151 

Its ^ CO 


-Id 
OS 


-fel-p-ld 
(M IM (M 


-Id 


-Id -p. 

— IM CO 


»» 


-pi 


-pi 


-p» 


■^ 


-Id 
00 Tt e< 


-Id 
(N 


-p 
00 us 


-pi 

CO 


-Id 

CO <M Its 


-pi 
© 


-pi 
: us t» 


-pi 

IM 


to 


CO 


OS OS (N 


IM 


-«*i "5 


© 


-pi -pi 
IM : 


CO 


-pi 
: 1-1 »• 


sr 


-pi 


(N 


00 OO 1>. 


CO 


Its Its -> 


(M 


-HIM : 


-pi 

CO 


-pi 
: <M fr* 


OS 


-pi 

00 


- 


-p -1« -Id 
CO OC i-i 


-Id 


Its : -- 


to 


-pi -id 
<M : 


CO 


: us © 


-pi 
us 


00 


lb 




: >> : 

• 1 . 




0) S. * 




3 3 5 








li 



ON THE SELF-REGISTERING ANEMOMETER. 



339 



"3 


© CS «5 
IN-" 


00 
us 


-p 
OC IN r>. 

t>.oc to 


-Is 

IM 
'?1 


-p 

•"SI — to 
-* © us 


© 

IM 


sfsT 


CO 


-:s 
© 


Pi 


22 


CO PS ■ 


-ts 


so ; ; 


CO 




-Is 
-91 


-*s . 


-" 


-pi 
© 

IM 


- 


00 a<i -^ 


-Hp* 


-Is . -»< 
CO ; 


■* 


: us : 


US 


IM \ -1 


CO 


-Is 
CO 
<M 


© 




©" 
(N 


Si : : 


->s 
IM 


■ 05 . 


-Is 
CO 


-H,j< : 


us 


-pi 


Oi 


-15. Hc 

«e iM US 




-*l-|5» . 


CO 


:® : 


to 






CO 

CO 


CO 


« CC CO 


IM 


eo-^iN 


to 


-Is -»s 


US 


:« : 


CO 


-p) 
to 

CO 


t^ 




-■fn 
CO 


-IS 

COCO" 


-is 


-^-|s 
N CO " 


!>. 


-Is . . 


-is 


-pi 

00 
CO 


«o 






CO •<* US 


IM 


-is 

IM »» ©» 


-Is 

to 


-p-|s 


IM 


■* 


us 


in w 1 


CO 


-p 


-is 


IM-*C0 


OS 


. -p 
CO : — 


-Is 
-9" 


CO 


■* 


us t^lM 


^ 


in -* ■* 


-Is 

2 


us US Si 


-Is 
IM 


"* : : 


-P< 
-9< 


-pi 

-9- 
US 


« 


-is -is 
(N OS ITS 


<N 


-p-|s 

00 us ■* 


00 


CO©-* 


t^ 


-[S-«l 

OS <M -91 


to 


00 


(N 


ffl 50 (N 


CO 


->s-|s 
U5 US us 


to 


-91 to us 


US 


-(s 

to to 


2 


-pi 

-9' 


- 


©lis 


us 
CO 


-P 

■^us © 


OS 


-p-;s 
CO us us 


-iC 


-IS -is 
QO(M 


:^ 


© 
00 


< 


(M 


© Oi t* 


to 


■^ us CO 


t". 


us US to 


to 


to us IM 


CO 


OS 


- 


lis CO -^ 


-w 

?? 


-is-^ 
■* IM us 


S 


•* ■* to 


■* 


teiMf- 


-pi 

OS 


00 


o 


in us -"a" 


-Is 


CO IM»» 


<M 


-* <M to 


CO 
IM 


to-^ : 


-pi 


-pi 
to 


03 


F^ *l ■* 




-Is -IS 

-<eous 


© 


-is-te) 
IM ■* us 


. -Is 


-pi 

00 


00 
-9< 


oo 


«l CO (N 




50 . 


-Is 

to 


-H tC ^ 


-IS 

OS 


IM :" 


-pi 
CO 


CO 


»-. 


-p. 

US © «o 


-p 


i^r-*" 


CO 


-Is 


^ 


-^ . 


-pi 
IM 


-Is 

to 

CO 


to 


to 00 CO 


CO 


-fei 

IM ffi : 


-p 


CO : 


-p 

CO 


-^ 


-,pl 

IM 


-Is 

OO 

(M 


lO 


■>f N CO 


05 


-i« . 

■* in ; 


OS 


-^s-is . 

(M : 


CO 


-Is 
; 00 1—1 


-P> 
OS 


■"If 


■^ 


CO Si !0 


-Id 


-< : IM 


CO 


: w 1 


CO 


-Is 


-p> 

IM 


i 


CO 


«p -^ «p> 
CO -^ m 


-P 


-P-P* 

CO — 


us 


. -Is . 

• CO : 


-Is 
CO 


;- : 


- 


CO 
IM 


IN 


-la 

0» SOUS 


CO 


-p . . 


-pi 


-Is 

-HIM : 


-p 

CO 


; US -91 


-pi 

OS 


CO 


- 


US® ^ 


-p 

to 


CO 1 \ 


CO 


-H us 1 


to 


; ►- IM 


-pi 

CO 


OS 
(M 


^ 








J3 

« o. ta 








f-t; o 

ccOZ 




'U 



Z2 



340 



REPORT— 1840. 



CD 



i 


5<i in iM 

O IN O 


CO 




-Hft» 

Oi 

in 


O CO IN 

to -^ in 


to 
in 


O -COO 
IN to -^ 


-ft. 
en 

CO 


-ft. 
to 


CM 


(N 


CC to 03 


IN 


-I" ; 


-p 


IN CO 


to 


: >-< en 


CO 


00 


^ 


.-^ -^ .h|« 

CO t^m 




-is-^ 


■* 


« (N 


-ft. 
'I' 


.-IS 


-ft. 

O) 


on 


© 


INtCt^ 


"5 


-.p-p 


■* 


. -»< 


-^ 


-ft. 


-ft. 

CO 


eo 


o> 


^ W IN 


to 


— (N -^ 


in 


-H> . . 


-fti 


-ft. 


-ft. 

CO 


-ft. 
in 


CC 


1-1 00 IN 


IN 


IN to >- 


o 

IN 


- : ; 


- 


. . -ft. 
: : "* 


-ft. 


-ft. 
CO 


». 


ifl CO IN 


- 


-|o<-!ci~^n 


CO 

IN 


CO : 


-<)< 


. -fti -ft. 
m 


to 


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ON THE SELF-RKGISTERING ANKMOMKTER. 



341 



1 


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342 



REPORT 1840. 



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ON THE SELF-REGISTEKING ANEMOMETER. 



343 



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344 



REPORT — 1840. 



9k 


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1 



ON THE SELF- REGISTERING ANEMOMETER. 



345 





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346 



REPORT — 1840. 





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ON THE SELF-REGISTERING ANEMOMETER 




I 



349 



Report respecting the Two Series of Hourly Meteorological 
Observations kept at Inverness and Kingussie, at the Ex- 
pense of the British Association, from Nov. \st, 1838, to 
Nov. \st, 1839. Btj Sir David Brewster, K.H.,F.R.S.,&c. 

Having selected Inverness and Kingussie as two suitable sta- 
tions foi* carrying on the two series of hourly observations with 
the thermometer and barometer, I prevailed upon the Rev. 
Mr. Rutherford, of Kingussie, and Mr. Thos. Mackenzie, 
Teacher of Raining's School, Inverness, to undertake these 
observations. The necessary instruments were made by Mr. 
Adie, of Edinburgh, under the superintendence of Prof. 
Forbes, and the observations begun on the 1st of November, 
1838, that month being the commencement of the meteorolo- 
gical year, or the^^r*^ of the group of winter months. 

While these observations were in progress, I communicated 
to the Association at Birmingham a specimen of those made 
at Kingussie, with a brief notice, which is published in the 
Report of last year. I have now the satisfaction of laying be- 
fore the Association the observations themselves, forming two 
quarto volumes, a work of stupendous labour, executed, for 
the first time, by educated individuals, with the aid of properly 
instructed assistants. 

The observations made at Kingussie, and, to a certain ex- 
tent, those made at Inverness, contain ampler details of me- 
teorological phsenomena than any series of hourly observations 
with which I am acquainted. In addition to the thermome- 
trical observations, the height of the barometer and the tem- 
pei'ature of the mercurial column were observed every hour. 
The general character of the iveather was carefully noted. 
The character and direction of the wind at every hour was 
recorded. The number of hours of wind, of breeze, of calm, 
o^ rain, oi snow, and oi cloudy and clear weather were regu- 
larly marked ; and the number and nature of the Auroree Bo- 
reales were recorded and described. 

When these observations are compared with those made at 
Leith, under my superintendence, hrfour years, from 1824 to 
1827 inclusive, at the expense of the Royal Society of Edin- 
burgh, — with those made at Plymouth, from 1832 to 1840, at 
the expense of the Association, and under the able superin- 
tendence of Mr. Snow Harris, — and with those made at Padua, 
Philadelphia, and in Ceylon, we perceive very distinct traces 
of meteorological laws, of which no idea had been previously 



350 



REPORT 1840. 



formed ; and I have no hesitation in stating, that when this class 
of observations are multipHed and extended, they will tend to 
general results of as great importance in pre-determining at- 
mospherical changes, as those which have enabled the astro- 
nomer to predict the phaenomena of the planetary system. 

Sir David Brewster then proceeded to give a brief and 
general account of the results obtained from the observations 
in Inverness-shire, leaving the numerical and more minute de- 
tails for the report, which will be published in a future 
volume of the Transactions of the Association. 

In giving an account of the observations on temperature, the 
results obtained at Kingussie and Inverness were compared 
with hourly and two-hourly observations made in other places, 
as exhibited in the following table : 



Places of Observation. 



Latitude, 
N. 


Longitude. 


Height 
above 
til c sea. 


57 29 34 


I 12 w. 


feet. 

92 


57 4 


4 5 w. 


750 


55 56 


3 13w. 


25 


5021 


4 6w. 


75 


45 36 


1155 E. 




39 57 


75 9 w. 




6 57 


80 E. 


36 


.718 


80 49 E. 


1682 


8 33 


81 24 E. 


60 



Distance 

from the 

sea. 



Mean 
temp. 



= 5 
E c 



% c ^ =" 



Inverness 
Kingussie 
Leith 



Plymouth 

Padua 

Philadelphia .. 

Colombo 

Kandy 

Trincomalee .. 



1 mile 
40 miles 
600 feet 
400 feet 



2 miles 



45 33 
42 78 

48 36 
52 

49 28 

80 16 
1 
74 5 

81 



8 31 

8 51 

9 13 
8 

8 41 
8 10 

10 35 

10 

10 35 



h , h 
7 4411 13 

7 35110 44 

8 2711 15 
7 111 

7 52,11 14 
7 3011 20 



9 30 
9 



10 55 
11 



8 4011 5 



Mean of all 11 5 



From this table it appears that the mean value of the critical 
interval is 11 hours 5 minutes, differing only 10 minutes from 
the result which Sir David Brewster first obtained from the 
hourly observations at Leith. 

Sir David then stated to the Section, that since the Asso- 
ciation met he had obtained from Mr. Caldecott (now present), 
Astronomer to His Royal Highness the Rajah of Travancore, 
the result of a series of hourly observations made at the Ob- 
servatory of Trevandrum, situated in east longitude S^ 8™, and 



METEOROLOGICAL OBSERVATIONS AT INVERNESS, &C. 351 

north latitude 8° 30' 35". These observations were made in con- 
sequence of the Rajah having seen the recommendation to esta- 
bhsh hourly observations in the first volume of the Report of 
the British Association. The hours of mean temperature ob- 
tained from these valuable observations, are 

Morning mean 8*^ 34''5 

Evening mean 7 31 



Critical interval 



10 56-5 



agreeing within 8^ minutes of the mean results given in the 
preceding table. 

Sir David Brewster then directed the attention of the Sec- 
tion to the following representation of the mean annual curves 
of daily temperature at Leith, Plymouth, Kingussie, Inver- 
ness, and Trevandrum. He pointed out the similarity (ap- 




proaching to almost entire coincidence) between the curves of 
Kingussie and Plymouth ; an elevation of 750 feet above the 
sea, producing the same effect as a diminution of latitude of 
SIX degrees. He also drew the attention of the Section to the 



352 REPORT— 1840. 

curve of Trevandrum* (marked by a dotted line), in which 
the daily range for the annual curve greatly exceeds that of 
all the other curves in the diagram, a new result which no 
person could have anticipated. 

JBarometrical Observations. 

Sir D. Brewster then proceeded to give a general account 
of the barometrical observations. The daily oscillations which 
they indicated correspond both in time and in magnitude with 
those which had been made in other parts of the world ; but 
as the corrections had not yet been applied to all the observa- 
tions, it was deemed unnecessary to make a more minute state- 
ment. 

Observations on the Wind. 

In comparing the number of hours of calm throughout the 
y^ar, it appeared that they occurred when the temperature 
was lowest, and upon laying them down in a curve this curve 
was almost exactly the reverse of that of the mean daily tem- 
perature for the year ; that is, the wind, or the commotions 
in the atmosphere, depends on and varies with the tempera- 
ture. 

" This very important and new result," Sir D. Brewster 
remarks, " is confirmed, in a remarkable manner, by the ob- 
servations of Mr. Osier at Birmingham, made at the request 
and expense of the British Association, which I have seen 
since I arrived in Glasgow ; observations of inestimable value, 
which exhibit more important results respecting the phaeno- 
mena and laws of wind than any which have been obtained 
since meteorology became one of the physical sciences." 

The Kingussie and Inverness observations contain many 
curious observations on the Aurora Borealis and other atmo- 
spherical phfenomena, for an account of which we must refer 
to a fuller report, which will appear in a future volume of the 
Transactions of the British Association. 

* The mean temperature is reduced 30°, so as to bring this curve among 
the other curves. 



353 



Report on the Fauna of Ireland: Div. Vertebrata. Drawn 
up, at the request of the British Association, by William 
Thompson, Esq., ( Vice-Pres. Nat. Hist. Society of Bel- 
fast,) one of the Committee appointed for that purpose. 

PART I. 

It has been remarked to me, and by a distinguished naturahst, 
that the zoology of Ireland can hardly be worth attention, from 
the similai'ity it must bear to that of Great Britain, already so 
well known. But, properly considered, the zoology of an island 
which, in the eastern hemisphere, constitutes the most western 
land within the fifty-first and fifty-fifth degrees of north lati- 
tude, cannot but be highly interesting, especially in connexion 
with that most attractive subject, the geographical distribu- 
tion of animals. In Ireland, we find within the degrees of lati- 
tude just mentioned the extreme western limits to which all our 
species range that are peculiar to the eastern hemisphere. In 
Zoology, however, — that is, in Vertebratal zoology, forofitonly 
the present communication treats, — we do not (as some writers, 
without reflecting on the very different circumstances which in- 
fluence the distribution of animal and vegetable life, have an- 
ticipated,) find the same interesting results as in Botany. The 
West and South of the island do not present us with any of the 
Vertebrata of Portugal, the western Pyrenees, or the South of 
Europe, which are not found elsewhere in the British Islands. 
The Erica mediterranea, Menziesia polifolia, Arbutus Unedo, 
&c., have no animal representatives*. 

Throughout this Report it has been considered desirable to 
contrast the zoology of Ireland with that of Great Britain, — to 
present, in fact, a comparative list of the Vertebrata of the two 
islands. It must, however, be borne in mind, that all species 
found from the Channel Islands in the south, to the Shetland 
Islands in the north, are included in the British Fauna, and 
that within the degrees of latitude over which it extends, Ire- 
land occupies but one third. Ireland is comprised within 
four degrees, whilst the Shetland Islands range nearly six de- 
grees further to the north, and more than two degrees to the 
south the Channel Islands are situated. The Fauna of Great 
Britain also extends over ten degrees of longitude, whilst that 
of Ireland is limited to half the number. 

The physical geography of Ireland must, like that of every 

* What may be the distribution of Lepus hibernicus and Mus hibernicus 
is yet indeed a problem. 

1840. 2 a 



354 REPORT — 1840. 

other country, have a primary influence on the numher of indivi- 
duals of the species which are found there either permanently or 
as periodical visitants. At the same time, its natural features do 
not differ so much from those of Great Britain as altogether to 
preclude the presence of more than one, or perhaps two, verte- 
brate animals, which have a place in the British and not in the 
Irish Fauna. These are the Ptarmigan ( Tetrao Lagopiis) and 
Alpine Hare. For the abode of the former, it does not afford 
a continuity of mountains of sufficient altitude and of such a 
nature as this bird chiefly inhabits. The haunts of the Alpine 
Hare [Lepits variabilis) are pretty similar to those of the 
Ptarmigan, but often at a much lower elevation. 

The influence of climate is now to be considered ; and under 
this head the species just mentioned might perhaps with pro- 
priety have been included. The difference between the tempe- 
rature of Ireland and Great Britain cannot with any degree of 
certainty be said to attract to, or repel from, our island, any 
species of the British Vertebrata. Our mild winters in par- 
ticular have otherwise great influence. The Stoat {Mustela 
erminea), for instance, very rarely in winter changes the co- 
lour of its summer fur to the warmer and more attractive garb 
of the Ei'mine, in which it is so much better known. Even in 
the north of the island, some species considered as birds of pas- 
sage in England, except in the extreme south, are induced to 
become residents, as is the case with the Grey Wagtail {Mota- 
cilla Boarula), and to a very great extent with the Quail 
{Perdix Coturnix). Of the Grallatores, some few species re- 
main throughout the winter in the North of Ireland, although 
only to the South of England are they known at this season. 
But, above all, the mildness of our winters is such, that some of 
the soft-billed birds, which are generally able to procure an 
abundance of food, are more disposed than in the neighbouring- 
island to song, and accordingly at this period of the year de- 
light us with much more of their music. 

The humidity of our climate would seem to attract to fa- 
vourite localities more Woodcocks {Scolopax Rusticola) than 
are found in any part of Great Britain, and, together with the 
great extent of bog throughout the island, brings hither to 
winter many more of the Jack Snipe {Scoloj^ax GalUnula), 
and of the common Snipe [Scolopax Gallinago). The two 
last, above all other birds, exceed in number those found in 
England and Scotland. The indigenous Starlings and Snipes 
are as nothing compared with the numbers that pour into the 
island during autumn from their breeding-haunts in higher 
latitudes. 



ON THE FAUNA OF IRELAND. 355 

Our moist and rich meadows draw hither in spring more 
Land-Rails {Crex pratensis) than are generally to be found 
in the meadows of England and Scotland ; but in the case of 
this bird, the far-western position of Ireland should perhaps be 
considered, as in Portugal the species is about equally 
abundant. 

Mammalia. — It is so extremely difficult to procure the greater 
number of the animals of this class, that some, especially of 
the smaller species, are doubtless yet to be discovered ; as 
known at present, they appear to fall short of those of Great 
Britain in an extraordinary degree. In the Cheiroptera, or 
Bats, we seem to be remarkably deficient, but time must add 
more species to our list. In the genus Mus there is a species 
- — the M. hibernicus — as yet unknown elsewhere. The Squirrel 
(Sciurus vulgaris) and Dormouse {Myoxus avellanarius) are 
desiderata : of the genus Arvicola I have not seen an Irish 
example. In Lepus, the place of L. timidus and L. varia- 
bilis is supplied by L. hibernicus, as yet known only to Ireland. 
In Mustela, the Polecat {M. Putorius) is unknown to me ; and 
if M. vulgaris be indigenous, it is much more rare than M. 
erminea, which prevails from north to south. Oi Felis Catus, 
as an Irish animal, positive information is yet wanted. The 
Talpa europcBa we certainly have not, though in Great Britain 
mole-hills may be observed close to the sea-side at some of 
the nearest points of land to Ireland, as at Holyhead in 
Wales, and Portpatrick in Scotland. The Soreces at present 
known are but two in number. 

Ireland possesses as many Birds as from her geographical 
position might be anticipated. The species which appear in 
the catalogue of Great Britain and not in that of Ireland, are 
chiefly occasional visitants, many of which have no doubt ex- 
tended their flight hither, although they have not come under 
the cognizance of the naturalist. This refers chiefly to strag- 
glers or single birds ; the species which come in flights to 
Great Britain generally extend their migration to Ireland also. 

In the class Reptilia nothing particular need be remarked, 
except the well-known fact of the absence of Ophidian Rep- 
tiles from the island. 

In Amphibia we have not the Toad {Bufo vulgaris) ; the 
Frog {Rana temporaria) is stated to have been introduced ; 
the Natterjack {Bufo Calamita) is believed to be truly indi- 
genous to Kerry. 

The coast of Ireland offers nothing very remarkable in 
Fishes. The families having a place in the British catalogue 
and in which the Irish is particularly deficient, are Percidce, 

2 A 2 



356 REPORT — 1840. 

Sparida, and Tcenioidece. In fresh-water fishes there is, com- 
pared with England, a remarkable poverty in the species of 
Cyprinidce ; yet, leaving out of the question geological in- 
fluences, there are in certain portions of Ireland lakes and 
rivers apparently well suited to this family. Scotland too is 
very deficient in the Cyprinidce. 

In the following catalogue of the vertebrate animals of Ire- 
land about 420 species are included ; namely, of Mammalia, 
SO?; Aves,^?>^l; Reptilia,2; Amphibia, 4<; Pisces, 150 f.; 
omitting in each class all extinct and naturalized species. To 
take a general review of the Irish Vertehrata, as known at 
present — and every year several species are added to the cata- 
logue — and of the causes of the absence of species found in 
Great Britain, it is believed that the physical geography and 
climate of the island will account for that of only one or two. 
The want of old timber over the country might be considered 
an obstacle to the presence of certain Mammalia and Birds, 
as the Cheiroptera, or Bats, a large proportion of the British 
species of which inhabit old trees ; the Squirrel, &c. In Birds, 
the Picidce, or Woodpeckers, their congeners, and some others. 
The absence of all species which would not be affected by any 
of the above circumstances, and which we really have not, 
seems to me to be attributable to geographical distribution 
alone ; thus, as the shores of continental Eui'ope on the same 
parallels of latitude as Great Britain are the western boundary 
to many vertebrate animals unknown to that island, so again 
are the shores of the latter the extreme western boundary to 
many species unknown to Ireland *. 

Note 1. — The North-east of Ireland and South-west of 
Scotland, although divided by so narrow a channel, are zoolo- 
gically very different. The species unknown to me as Irish, 
but of which I have seen examples from the opposite coast, 
are, the Polecat {Mustela Putorius), Mole {Talpa europcea). 
Ciliated Shrew {Sorex ciliatus), the three species of Campa- 
gnol [Arvicola amphibia, A. agrestis, and A. riparia), and the 
common Hare [Lepus timidns) — the Black Grouse {Tetrao 
Tetrix) — the Blind-worm {Anguis fragilis). Adder or Viper 
{Pelitts Berics), and Toad {Btifo vulgaris). 

In the genera to which the animals just mentioned belong, 
Ireland is known to possess but one species which is not found 
in Scotland, the Lepus hibernicus, and of the terrestrial Mam- 
malia generally, but one other, Mus hibernicus : of the com- 

* Several species of British Birds are either not found in the West of En- 
gland, or become rare towards that quarter ; as the Nightingale, Nuthatch, 
Wryneck, Kentish Plover, Stork, &c. 



ON THE FAUNA OF IRELAND. 357 

men Shrew-mouse of Ireland {Sorex rusticus), indeed, I have 
not seen any specimens from Scotland, but there can be little 
doubt that the animal is found there. 

Note 2. — The situation of the Isle of Man — midway between 
Great Britain and Ireland — suggests the inquiry whether cer- 
tain species not found in the latter island pievail there. On 
this subject Mr, E. Forbes informs me that the Mole, Squirrel, 
Dormouse, and Roe-deer are not indigenous to the Isle of 
Man; neither is the Toad, nor any species of Ophidian Rep- 
tile. A skin of the Hare of the island sent me by Mr. Forbes 
is that of L, timidus, the species found in Great Britain, and 
represented by L. hibernicus in Ireland*. 

* It may be desirable, witb reference to the above remarks, to allude briefly 
to such species as, found in Great Britain and not in Ireland, prevail further to 
the west. In Mammalia, five of the British and non-Irish species are found in 
the western hemisphere. They all belong to the division Mamm. Aquatica, 
and are only occasional visitants' to the shores of Great Britain. The species 
are Calocephalus (Phoca) groenlandicus, Trichecus rosmarus, Delphinus I'ursio, 
Delphinapterus {Beluga) leucas, Monodon Monoceros. 

In Aves, sixteen British and non-Irish species prevail in the western hemi- 
sphere. Of these, the Ptarmigan {Lagopus mutus) onl}' can with certainty be 
termed indigenous to Great Britain, and for its absence from Ireland reasons 
have already been assigned. Linaria canescens seems not yet to be properly 
established as an indigenous British bird. Two species, Pracellaria glacialis 
and Lobipes kyperboreus, are periodical visitants, the former to St. Kilda only, 
the latter to the northern Scottish islands. The remaining twelve are occa- 
sional and very rare visitants to Great Britain or the neighbouring seas. 
They are Nauclerus {Elanus) furcatus, Surnia funerea, Plectrophanes Lappo- 
nica, Ectopistes (Columba) migratoria, Macroramphus griseics, Tringa rufes- 
cens, Tringa pectoralis, Oidemia perspicillata, Clangula histrionica, Merganser 
cucullatus, Larus atricilla, and Thalassidroma Wilsoni, 

In Reptilia, two species which have a place in the British and not in the 
Irish catalogue, belong to the western hemisphere : these are Chelonia imbricafa 
and Sphargis coriacea. 

In Amphibia, none of the species under consideration occur in the west. 

In Pisces, several British and non-Irish species appear in the North Ameri- 
can list, but they are all known only as rare and occasional visitants to the 
shores of Great Britain. They are Trichiurus lepturus, Sebastes norvegicus, 
Naucrates Ductor, Exocoetus exiliens, Engraulis enerasicholus ?, Echeneis Re- 
mora, Murcsna vulgaris ?, Zygeena malleus, Scopelus Humboldtii, and Xiphias 



The Mammalia, Reptilia, and Pisces of the West are taken (with the excep- 
tion of Sphargis coi-iacea) from Dr. Richardson's " Report on North American 
Zoology," (Report Brit. Assoc, vol. v.), and Dr. H. Storer's " Report on the 
Fishes &c. of Massachusetts ;" Aves, from the Prince of Musignano's " Com- 
parative Catalogue of the Birds of Europe and North America." 



* Throughout this Report, the term indigenous is applied to species perma- 
nently resident ; periodical visitant, to those which come annually ; occasional 
visitant, to those met with at uncertain intervals. 



358 REPORT— lS4a 



PART II. 

Div. VERTEBRATA. 

Class MAMMALIA— Sect. I. MAMM. TERRESTRIA, 

Order 1. — Cheiroptera. 

Fam. Vespertilionida. 

[Throughout the comparative catalogue, the mark denotes absence, as the 
mark + does presence. Thus Vesp. Noctula is unknown in Ireland ; 
V. Pipktrellus is a British as well as an Irish species.] 

Ireland, Great Britain, 

Vespertilio Noctula, Sclireh. 

„ Leisleri, Kuhl. 

Q „ discolor, Natt. 

Vespertilio Pipistrelhis, Geoff. •+- 

G 3j pygTOEeus, Leach. 

„ serotinus, Gmel. 

,s murinus, L. 

,, Bechsteinii, Leisl. 

O „ Nattereri, Kuhl. 

„ emarginalus, Geoff. 

,, Daubentonii, Leisl. + 

„ m)'stacinus, Leisl. 

„ aedilis, Jenyns. 

Plecotus auritus, Geoff. + 

Plecotus brevimanus, Jenyns, 

Barbastellus Daubentonii, Bell. 

Rhinolophus Ferrum-equinum, Leach. 

„ hipposideros, Leach. 

Of the Vespertilionidce, of which 18 species are now enume- 
rated as British, all that can be announced as Irish are the 
Vesp. Pipistrelhis, V. Daubentonii and Plecotus auritus : the 
first and last are common from north to south of the island : 
of the V, Daubentotiii^ , one individual was obtained by the 
Ordnance collectors in the county of Londonderry. That other 
species remain to be discovered, there is little doubt. 

Of the British Bats, 4 species have each been found, but in 
one locality ; and of 4 other species but a single individual has 
been procured. 

Order 2. — Bestije. 

(Ferae Insectivorae.) 

Fam. ErinaceidoB. 
Ireland. Great Britain. 

Erinacens europseus, L. + 

Common throughout the island. 

* The species determined by Mr. Jenyns. 



ON THE FAUNA OF IRELAND. SS^ 

Fam. Talpidce. 

Ireland. Great Britain. 

Talpa europaea, L. 

Fam. SoricidcB. 

Ireland. Great Britain. 

Sorex rusticus, Jenyns. -|- 

„ tetragonurus, Herm. -\- 

Sorex fodiens, Gmel. 

„ ciliatus, Sower. 

,, castaneus, Jenyns. 

S. rusticus is the common Shrew of Ireland from north to 
south ; of S. tetragonurus I have seen but one native speci- 
men, which was procured by the Ordnance Survey near the 
Giant's Causeway. 

Order 3 — FerjE. 

Fam. UrsidoE^. 

Ireland. Great Britain. 

Meles Taxus, Flem. -j. 

In suitable localities throughout 
the island. 

Fam. Felidee, 

Ireland. Great Britain. 

Lutra vulgaris, Erxleb. (?) f ^ 

Mustela vulgaris, L. (?) -f. 

„ erminea, L. j^ 

Mustela Putorius, L. 

Martes foina, Bell. ^ 

„ Abietum, Bai/. _|_ 

Felis Catus, L. 

Vulpes vulgaris, Briss. -j. 

The Irish Otter, named provisionally Lutra Roensis by Mr. 
Ogilby, is not now considered by that gentleman distinct from 
L. vulgaris ; it is not uncommon. Of the Mustelce, M. Puto- 
rius is unknown to me as Irish ; and of M. vulgaris, which is 
noticed as common by Templeton and others, 1 have not seen 
a native specimen : M. erminea is common from north to south, 
and passes under the name of 'Weasel'. Maries Abietum 
is found throughout the island ; of M. foina, but one native 
example (killed in the county of Antrim) is known to me. The 

* Ursus Arctos, L. I am not aware of any written evidence tending to show- 
that the Bear was ever indigenous to Ireland ; but a tradition exists of its having 
been so, and it is associated with the Wolf as a native animal in the stories 
handed down througji several generations to the present time. 

t The note of interrogation within brackets (?) marks species doubtfully Irish. 



360 REPORT — 1840. 

difference of colour attributed to these animals appears to me 
of no value as a specific character, as in course of shedding 
their fur they become particoloured, the breast as well as the 
body presenting at the same time the colours of the Beech and 
the Pine Marten*. Certain data for including Felis Catus in 
the Irish catalogue are wanting : it is said to frequent the wild 
district of Erris (co. Mayo). Vulpes vulgaris is common f. 

Order 4. — Glires. 
Fam. Castoridce. 

Ireland. Great Britain. 

Arvicola ampliibius, Desm. 

„ avvalis, Gm. (agrestis, Brit, au- 

thors). 
„ nibidus, Baill. (riparia, Yarrell). 

Of the genus Arvicola, there is not any species known to 
me as indigenous to Ireland. 

Fam. MuridcB. 

Ireland. Great Britain. 

Sciurus vulgaris, L. 

Myoxus avellanarius, Desm. 

Mus minutus, Pall, (messorius, Shaw.) 

Mus sylvaticus, L. + 

„ Musculus, L. -f- 

„ Rattus, L. (?) + 

„ hibernicus, Thomps. 

„ decumanus, Pall. + 

Sciurus vulgaris is not now a truly native animal % ; it was in- 
troduced a few years since to the county of Wicklow, where it 
is said to be fast increasing in numbers. Rutty, in his Natu- 
ral History of the County of Dublin, (1772,) vol. i. p. 291, re- 
marks that it is " said to have been found in the wood in 

* When the above was in the press, Mr. Eyton published in the Annals of 
Nat. Hist. (Dec. 1840, p. 290) some valuable remarks on the British Martens, 
tending to prove that they are in reality but one species. He states that the 
young animal has the yellow breast attributed to the Pine Marten, and the adult, 
the white breast of the common " species." I had also long since remarked that 
the yellow colour of the breast gave place to white. This view would satisfac- 
torily explain why the yellow-breasted one — M. Abietiim — should appear to be 
the more common with us, as by far the greater proportion of animals that fall 
victims to man are those which have not arrived at full maturity. 

f Canis Lupus, L. Smith, in his History of Kerry (p. 173), states that 
Wolves were not entirely extirpated in Ireland until 1710. That noble race of 
domestic animals, the Irish Wolf Dog, so successfully used in their pursuit, has, 
since no longer required, been neglected, and must now, I fear, be called 
extinct. 

X There is a tradition that the Squirrel was common in Ireland before the 
destruction of the native woods. 



ON THE FAUNA OF IRELAND. 361 

Lutterel's Town." In the same work it is observed in vol. i. 
p. 277, that " a vulgar error has prevailed, mentioned at Jon- 
ston's Historia Animalhcm, that the Dormouse was not found 
in Ireland," &c. ; a sort of description of the animal follows, 
but by no means proving it to be a Myoxus. Mus minutus 
cannot be announced as Irish ; but a native animal was once 
described to me which would agree with it ; M. sylvaticus and 
M. Musculus are both too common over the island. The ani- 
mal provisionally called Mus hibernicus* is now so rare that I 
have been able to obtain for examination but one specimen, 
which is insufficient to establish it properly as a distinct spe- 
cies ; M. Ratfus, though very rare, is stated to occur occa- 
sionally in various parts of the island . 

In his Natural History of Dublin, Rutty states that the Mus 
decumanus " first began to infest these parts about the year 
1722." (vol. i. 281.) It has long since overspread the island. 

Fam. Leporidce. 
Ireland. Great Britain. 

Lepus timidus, L. 

„ variabilis, Pall. 

Lepus hiberniciis, Bell. 

Cuniculus, L. -\- 

The only species of Hare known as Irish is the L. Mber- 
nicus, which is common throughout the island, as is likewise 
L. Cunicultisf. 

Order 5. — PecoraJ. 

Fam. CervidcB§. 

Ireland. Great Britain. 

Cervus Elaphus, L. + 

Cervus Capreolus, L. 

• Proceedings Zool. Soc. London, 1837, p. 52. 

f This animal passes under the names of burrow and bush Rabbit in the North 
of Ireland. These are distinguished from each other accordingly as they bur- 
row in the ground in the ordinary manner, or live in " forms " like the Hare 
among bushes or underwood. This departure from their natural habit is, I con- 
ceive, only resorted to where the soil is unsuited to burrowing. In the Annals 
of Nat. Hist. vol. v. p. 362, a notice will be found on the subject of Hares bur- 
rowing in an exposed situation on the western coast of Ireland, to which they 
were introduced, and where they could not otherwise find shelter. 

X Bos Taurus, L. The remains of a race of Oxen, believed to be peculiar to 
Ireland, are found in our bogs. The distinguishing characters are, " the con- 
vexity of the upper part of the forehead, its great proportional length, and the 
shortness and downward direction of thehorns." See an abstract ofa paper by 
Mr. R. Ball, " On the Remains of Oxen found in the Bogs of Ireland," in the 
Proceedings of the Royal Irish Academy, January 28, 1839. 

§ Cervus Dama, L. Smith, in his History of Kerry, notices herds of Fallow 
Deer as frequenting the " mountains" in that county. But as these are the 
haunts not of this animal, but of the Stag or Red Deer (C. Elaphus), the latter 



362 REPORT — 1840. 

The C. Elaphus, once abundant over Ireland, is now con- 
fined to the wilder parts of Connaught, as Erris and Conne- 
mara ; and to one or two locaUties in the South, more espe- 
cially the vicinity of the lakes of Killarney. 

Sect. II. MAMMALIA AQUATICA. 
Oi'der 6. — Pinnipeda. 
Fam. PhocidcB. 
Ireland. Great Britain. 

Plioca vitulina, L. + 

Phoca grcenlandica, Mull. 

„ barbata, Mull. 

Halichaerus Gryphus, Bell. + 

Trichecus Rosmarus, L. 



was probably tbe species alluded to, especially as in the index to the volume 
appears " Deer, red or fallow". For a long period the Fallow Deer certainly has 
not been found in any part of Ireland where it could be called truly wild. 
A horn of this species which I possess, (through the kindness of Edward Benn, 
Esq., of Glenravel, county Antrim,) is stated to have been dug up from a con- 
siderable depth in a bog in his neighbourhood, but minute particulars respecting 
it could not be obtained. It may not be out of place to observe here, that the 
C. Dania is now well known to inhabit Greece in a wild state. Lord 
Derby has for some years possessed a pair of these animals of the common 
spotted variety, which were brought from the neighbourhood of Axium by 
Lord Nuo-ent, and which, as I am informed by my friend Mr. Ogilby, who 
examined them attentively, during a recent visit to their noble owner, differ 
in no respect from the common Fallow Deer of our parks. Moreover, as re- 
marked by the same gentleman, the universal application of the word Dama 
to this animal in the Italian, French, Spanish, and other modern languages de- 
rived from the ancient Latin, (added to the fact of the animal being still found 
in the forests of Italy, where there are no parks or inclosures,) points it out as 
the beast of chase so frequently mentioned under the same name by the Roman 
poets. Mr. Ogilby hkewise remarks that it is in all probability the Platycerus 
of Pliny, or rather of the Greeks, from whom he copied. It is said in a note 
to the second edition of the Regne Jtiimal to have been found in the woods 
of Northern Africa. 

Cervus Alces, L. A horn of the true Elk (C Alces), as noticed by me in the 
" Proceedings of the Zoological Society of London," for 1837, p. 53, was some 
years since presented to the Natural History Society of Belfast. To the donor 
it was given by a relative residing at Stewartstown, county Tyrone, who attached 
much value to it as a singular relic dug out of a peat-bog on his own property 
in that neighbourhood. That it was so obtained I am assured there cannot be 
a doubt. The horn is that of a very old animal, and quite perfect. On re- 
moving the paint with which it was besmeared, the horn certainly presented a 
fresh appearance ; but might not this be attributed to the well-known preserv- 
ative property of the soil in which it is said to have been found? There is not, 
that I am aware of, any record of this animal having ever existed in a wild state 
in the British Isles ; but as it inhabited a wide range of latitude on the continent 
of Europe, it is within the bounds of probability to believe that it may have 
been a native species. 

Sus Scrofa, L. The Wild Boar was at one period common in Ireland, but 
has long since become extinct. Giraldus remarks that it was of a small race, 
but tusks of this animal dug up in our bogs are often of goodly dimensions. 



i 



ON THE FAUNA OF IRELAND. 363 

P. vittilina and Hal. Gryphus only, in this family, have 
with certainty been recognised as Irish species ; they both in- 
habit the coasts from north to south. 

Precise information is much wanted with reference to P. 
harbata as a British species ; and as such, P. grcenlandica (or 
the animal so considered to be) is a recent addition to the ca- 
talogue. Trich. Rosmarus very rarely occurs in the Hebrides 
and in the Orkney and Shetland Islands- 
Order 7. Cete. 
Fam. Delphinidce, 
Ireland. Great Britain. 

Delphinus Delphis, L. + 

Delphinus Tursio, Fahr. 

Phocsena communis, Less. + 

„ Orca, F. Cuv. -f- 

,, melas, Bell. + 

Beluga leucas, Bell. 

Hyperoodon Butzkopf, Lacep. + 

Diodon Sowei-bsei, Jard. 

Monodon Monoceros, L. 

D. Delphis, P. communis and P. Orca are considered to pre- 
vail on various parts of the coast of Ireland, the second to be 
the most common, the last the rarest ; of all, I have seen native 
specimens, but cannot from personal knowledge speak of the 
comparative abundance or scarcity of the species. P. melas 
has been observed on the western and southern coasts ; Hyp. 
Butsskopf along the eastern coast. The four Delphinidce 
which cannot be enumerated in the Irish catalogue are very 
rare as British species ; of Diodon Sowerbcei a single speci- 
men only is on record. 

Fam. BalcenidtB. 
Ireland. Great Britain. 

Physeter macrocephalus, L. -j- 

„ Tursio, L. -j- 

Balaena Mysticetus, L. -j- 

Balaenoptera Boops, Flem. -j- 

According to Dr. Molyneux*, the "Spermaceti Whale" 
has been captured on the north and north-west coasts. Smith 
notices one, taken near Youghal ; and Rutty, in his Natural 
History of Dublin, mentions an individual as cast ashore in 
1766. Templeton states that Phys. Tursio is of occasional oc- 
1 currence in the West. Bal. Mysticetus has been rarely cap- 
tured on various parts of the coast. Of a Balcenoptera {Ba- 
IcEna rostrata) which was taken on the western coast some years 
ago a very full account has been pubUshed by Dr. Jacob in the 
Dublin Philosophical Journal. 

* Phil. Trans., vol. xix. 1795-6, p. 508. 



364 REPORT — 1840. 



PART III. 

Class AVES. 
Order 1. — Raftores. 
Fam, VulturidcE. 
Ireland. Great Britain. 

Neophron Percnopterus, Sav. 

This bird has a place in the British Fauna from its occur- 
rence in England on one or two occasions. Africa is its head 
quarters. 

Fam. FalconidcB. 

Ireland. Great Britain. 

Aquila Chrysaetos, Vig. + 

Haliaeetus albicilla, Selby. + 

Pandion Haliseetus, Sav. + 

Astur palumbarius, Bechst. (?) + 

Accipiter fringillarius, Raij. + 

Falco groenlandicus, L. Hancoclc. + 

„ Islandicus, ZaiA. i/a«coc^.(?) + 

„ peregrinus, L. + 

„ Subbuteo, L. + 

„ rufipes, Bechst. + 

„ Tinmiiiculus, L. + 

„ ^salon, Gmel. + 

Buteo vulgaris, Bechst. + 

„ Lagopus, Vig. + 

Pernis apivorus, Cuv. + 

Circus rufus, Briss. + 

„ cyaneus, Flem. + 

Circus cineraceus, Shaw. 

Milvus Ictinus, Sav. + 
Elanus furcatus, Sav. 

The two first-named species, the Golden and Sea Eagles are 
in Ireland, as in Scotland, more numerous than in England. 
Pandion HaUceetus is chiefly confined to the more southern half 
of the island. Astur palumbaritis has a place not only in the 
older county histories, but in Mr. Tenipleton's catalogue; I have 
not myself seen any specimen which could be verified as native. 
Accipiter fringillarius, Falco peregrinus, F. Tinnunculus, F. 
jEsalon, Buteo vulgai'is. Circus rufus, and C. cyaneus, inhabit 
suitable localities throughout Ireland : in the wild and moun- 
tainous parts of the country which are destitute of wood, B. vul- 
garis makes the precipitous rocks its habitation. Falco groen- 



ON THE FAUNA OF IRELAND. 365 

landicus as distinguished by Mr. Hancock from F. Islandicus* , 
has in one instance been obtained in Donegalf : under the latter 
name Mr. Templeton records a specimen, killed in the county 
of Antrim, but as both these terms were then used synony- 
mously, it must remain doubtful whether it was this or the 
former species. By this naturalist the F. Subbuteo was on two 
occasions observed in Ireland. Falco riifipes has once been ob- 
tained, in the neighbourhood of Dublin. Biiteo Lagopus is 
a very x'are winter, as Pernis apivorus is a summer, visitant. 
Smith, in his History of Cork, (completed in 1749,) remarks of 
the Milvus Ictinus, "These birds are so common that they 

need no particular description ; with us it remains all 

the year J." At present the species is unknown in that county. 
The terms Kite and Goshawk being applied indiscriminately 
in Ireland to the Buzzards, and the latter sometimes to the 
Peregrine Falcon, renders it somewhat dubious whether the 
proper names have always been legitimately employed in the 
county histories, &c. The Milvus Ictinus has, on what was 
considered sufficient authority, been noticed as an extremely 
rare visitant to the North §. 

Of our desiderata, the Circus cineraceus is a species, which 
from its general resemblance to C. cyaneus, might readily be 
overlooked ; it will probably yet be added to the Irish cata- 
logue. Elanus furcatus, an American species, has only twice 
been taken in Great Britain. 

Fam. Strigidce. 

Ireland. Great Britain. 

Bubo maximus, Sibbald. + 

Otus vulgaris, Flem. + 

„ Brachyotos, Cuv. -\- 

Scops Aldrovaudi, Will. 8f Ray. + 

Surnia nyctea, Dum. + 

Surnia funerea, Dum. 

Strix flammea, Z. + 

Ulula stridula, Selby. + 

Noctua Tengmalmi, Selby. 

,, passorina, Selhy. 

Of the occurrence of either Btibo maximus or Scops Aldro- 
vandi in Ireland, there is but a single record. Otus vulgaris 

* Annals of Natural History, vol. ii. p. 249. 

f The description of this individual, supplied me, previous to the appearance 
of Mr. Hancock's paper, by John Vandeleur Stewart, Esq., of Rockhill, 
Letterkenny, in whose collection it is, is so ample, as to prove its species 
beyond any doubt. 

X Vol. ii. p. 326, 2nd edit. 

§ Ann. Nat. Hist., vol. i. p. 156. 



366 REPORT— 1840. 

and Strix flammea are common and resident. Otus Brachyo- 
tos is a regular winter resident ; at the same season Surnia 
nyctea has occasionally been met with. Ulula stridula is in- 
cluded in the older county histories ; on what was considered 
sufficient authority it was noticed as an Irish species in Annals 
of Natural Histoi'y, vol. i. p. 156. 

Surnia funerea has its place in the British catalogue from a 
single individual having been taken off the coast of Cornwall. 
Noctua Tengmalmi and N.passerlna have been very rarely met 
with in England. 

Order 2 — Insessores. 
Div. 1. — Dentirostres. 
Fam. Laniadce. 
Ireland. Great Br'Uain, 

Lanius Excubitor, L. + 

Laniiis Collurio, Z. 

,, rufus, L. 

The L. Excubitor only in this family can be announced as 
Irish : its occurrence in a number of instances is on record. 

L. Collurio is a regular summer visitant to England ; L. 
rufus but a very rare and occasional one. 

Fam. MuscicapidcB. 

Ireland. Great Britain, 

Muscicapa grisola, L. + 

Muscicapa luctuosa, Temm. 

M. grisola is a regular summer visitant to Ireland. 
M. luctuosa is in England considered only as an occasional 
visitant (Selby). 

Fam. Merulidce. 



Ireland. 


Great Britain. 


Cinclus aquaticus, Rechst. 




+ 


Merula viscivora, Selby. 




+ 


„ pilaris, Selbi/. 




+ 


„ musica, Selby. 




+ 


„ iliaca, Selbij. 




+ 


„ vulgaris, Ray. 




+ 


„ torquata, Selby. 




+ 





Merula Whitei, 


Jard. 


Oriolus Galbula, L. 




+ 



Cinclus aquaticus, Mer. musica and M. vulgaris are com- 
mon and resident ; so likewise is M. viscivora, but not to the 
same extent, although its increase in Ireland of late years has 



ON THE FAUNA OF IRELAND. 



367 



fully kept pace with that in Great Britain : so mild have been 
our few last winters, that the song of M. musica was almost 
daily heard. Mer. pilaris and M. iliaca regularly take up 
their abode with us in winter, as does M. torquata in summer. 
Oriolus Galbula has in a few instances been met with in 
various parts of Ireland, and as far north as Donaghadee, co. 
Down. 

Mer. WJiitei has on two occasions occurred in England. 



Fam. 


Sylviadce. 


Ireland. 




Great Britain. 


Accentor modularis, Cuv. 




+ 







Accentor alpinus, Bechst. 


Ery thaca Rubeciila, Swains. 




+ 


Phoenicura Riiticilla, Swains. 




+ 


„ Tithys, Jard. 8f Selby. 




+ 







Phoenicura Suecica, Selby. 


Saxicola (Enanthe, Bechst. 




+ 


„ Rubetra, Bechst. 




+ 


„ Rubicola, Bechst. 




-4- 


Salicaria Locustella, Selby. 




+ 


„ Phragmitis, Selby. 




+ 


„ arundinacea, Selby. 




+ 







Philomela Liiscinia, Swains. 


Curruca Atricapilla, Bechst. 




+ 


„ hortensis, Bechst. 




+ 


„ cinerea, Bechst. 




+ 







Curruca Garrula, Briss. 







Melizophilus provincialis, Leach. 


Sylvia Hippolais, Lath. 




+ 


„ Sibilatrix, Bechst. (?) 




+ 


„ Trocbilus, Lath. 




+ 


Regulus Aurocapillus, Selby. 




+ 







Regulus ignicapillus, Jenyns. 


Parus major, L. 




+ 


„ coeruleus, L. 




+ 


„ palustris, L. 




+ 


„ atei-, L. 




+ 


- „ caudatus, L. 




+ 







Parus cristatus, L. 


Calaniophilus biarmicus, Leach. 




+ 


Motacilla Yan-ellii, Gould. (M. alba, 


+ 


preceding British authoi-s). 






Motacilla Boarula, L. 




+ 


„ flava, Bay. 




+ 







Motacilla neglecta, Gould. 


Anthus obscurus, Temm.* (Rock Pipit, 


+ 


Brit, authors). 






Anthus pratensis, Bechst, 




+ 


„ arboreus, Bechst. (?) 




+ 







Anthus Richardi, Vieill. 



* Not ^. aquaticus, Bechst. See Temm. Man., part iv. p. 929. 



368 REPORT — 1840. 

Accentor modularis, Erythaca Riibecula, Saxicola Rubicola , 
Regulus Aurocapillus, Parus major, P. cosruleus, P. ater, Mo- 
tacilla Yarrellii, M. Boarula, Anthus ohsctirus, A. 'pratensis 
are common and resident : in the wilder districts, especially 
towards the west, M. Boarula is rare. Parus caudatus and P. 
palustris are likewise resident, but much less common than the 
preceding species ; the former is increasing with the spread of 
plantations ; the latter is very little known as an Irish bird. 
Phceriicura Ruticilla is but of occasional and rare occurrence ; 
Ph. Tithys can only be announced with certainty as having 
once been met with. Saxicola CEnauthe, S. Ruhetra, Sali- 
caria Phragmitis, Curruca cinerea, Sylvia Trochilus are the 
most common and widely dispersed of the regular summer visit- 
ants; Salicaria Locustella should perhaps be included with 
them, but its retired habits render it less known. Salicaria 
arundinacea is recorded by Templeton as once seen by him 
near Belfast, and in a single instance Cakmiophilus biannicus 
has been obtained on the banks of the Shannon. Ctirruca 
Atricajiilla is probably a regular summer visitant to select 
localities, and has in several instances been known to winter 
in Ireland. C. hortensis is with certainty known only as an 
occasional summer visitant. Sylvia Hippolais and Motacilla 
fiava appear every summer in comparatively few localities over 
the island. Sylvia Sihilatrix and Anthus arboreus are believed 
to visit Ireland in summer, but it yet remains to be determined. 

Of our desiderata, Accentor alpinus, Phcenicura suecica, 
Regulus Ignicapillns, and Anthus Richardi are only known as 
rare and occasional visitants to England. Motacilla neglecta 
cannot without further information be regarded otherwise than 
a species of occasional occurrence in Great Britain. There is 
little hope of Partis cristatus being found in Ireland : it is, as a 
British bird, known only in Scotland, where it especially fre- 
quents the pine forests. Melizophilus j^rovincialis has been 
met with only in the more southern half of England. Of Phi- 
lomela Luscinia and Curruca Garrula, the former is unknown 
in the West of that country, and the latter would seem to be- 
come rare towards the same quarter. With increased atten- 
tion, more species in this family will doubtless be added to the 
Irish catalogue. 

Fam. AmpelidcE. 

Ireland. Great Bi-itain. 

Bombycilla garrula, Bonap. + 

An occasional winter visitant to Ireland. 



ON THE FAUNA OP IRELAND. 



369 



Order Insessores. 

Div. 2. CONIIIOSTRES. 

Fam. Fri7igillidcB. 



Ireland. 




Alauda arveiisis, L. 
„ arborea, L. 

Plectrophanes nivalis, Meyer. 
Emberiza Miliaria, L. 
„ Schoeniculus, L. 

„ Citrinella, L. 



Fringilla Coelebs, L. 

„ Montifringilla, L. 
Passer domesticus, Ray. 


Coccothraustes vulgaris, /'/6>?w.(Fring. 

Coccotbraustes, Temm.) 
Coccothraustes Chloris, Fletn. 
Cardiielis elegans, Steph. 
„ Spinus, Steph. 

Linaria minor, Ray. 
„ cannabina, Sw. 
„ montana, Ray. 

Pyrrhula vulgaris, Temm. 

,, Enucleator, Tern. (?) 
Loxia curvirostra, L. 

„ leucoptera, Gmel. 



Great Britain. 
Alauda alpestris, L. 

+ 

Plectrophanes Lapponica, Selby. 

+ 

+ 

+ 
Emberiza Cirlus, L. 
„ hortulana, L. 

+ 

+ 

+ 
Passer montanus, Ray. 

+ 

+ 
+ 
+ 
+ 

-f 
Linaria canescens, Gould. 

+ 

+ 
^ . + 

Loxia Pytiopsittacus, Bechsf. 

+ 



Alauda arvensis, Emb. miliaria, E. Schcenicidus and E. 
Citrinella, Fring. Ccelebs, Pass, domesticus, Coec. Chloris, 
Linaria minor and L. cannahina are common and resident. 
Alauda arborea. Card, elegans, Lin, montana and Pyrr. vul- 
garis are likewise resident, but more local than the others. 
Plect. nivalis is a regular winter visitant to the North of Ireland, 
but little known in the South ; Fring. Montifringilla is a fre- 
quent, perhaps a regular visitant at. the same period. Cocc. 
vulgaris. Card. Spinus, and Loxia curvirostra occasionally 
visit us in winter, the first-mentioned being the most rare, and 
occurring in the fewest numbers ; the last-named has in some 
instances bred in Ireland. Pyrr. Enucleator would seem 
from a note of Mr. Templeton's to have been once met with 
near Belfast. Loxia leucoptera has been obtained on one 
occasion. 

1840. 2 B 



370 REPORT — 1840. 

Alauda alpestris, Pled. Lapponica, Emh. Jiortulana and 
Loxia Pytiopsittacus^ are very rare and occasional visitants 
to Great Britain. Emheriza Cirlus and Passer montanus are 
local species in England, the former visiting only a portion 
of the South. Linaria canescens I have not yet sought to 
distinguish from its allies. 

Fam. Sturnidce, 

Ireland. Great Britain. 
Sturnus vulgaris, L. + 

Pastor roseus, Temm. + 

The former species is somewhat local and partially resident ; 
it abounds in particular localities during winter. The latter is 
a rare summer visitant, but has been met with in all quarters 
of the island. 

Fam. CorvidcB. 

Ireland. Great Britain. 

Fregilus Graculus, Selb. + 

Corvus Corax, L. + 

„ Corone, L. + 

„ Cornix, L. + 

„ Frugilegus, L. + 

,, Monedula, L. + 

Pica melanoleuca, Vieill. + 

Garrulus glandarius, Flem. + 

Nucifraga Caryocatactes, Briss. 

Freg. Graculus is pretty generally diffused over the marine 
cliiFs of Ireland, and rarely inhabits inland localities. All the 
species of Corvus are resident and common ; C. Corone least 
so. Of Pica melanoletica it is stated by Smith, in his History 
of Cork, (1749,) that it "was not known in Ireland seventy years 
ago, but is now very commonf . Rutty, in his Natural History 
of Dublin, observes respecting this bird, " It is a foreigner, 
naturalised here since the latter end of King James the Se- 
cond's reign, and is said to have been driven hither by a strong 
wind. "J Garr. glandarius inhabits only some parts of the 
island, especially towards the centre and south. 

Nucif. Caryocatactes is but a rare visitant to Great Britain. 
I have heard that it once occurred at Silvermines, co. Tippe- 
rary. 

* It is more than probable that some of the later British specimens noticed 
as this bird were merely L. curvirostra, with the point of the lower mandible 
not extending beyond the profile of the upper. 

t Vol. ii. p. 330. X Vol. i. p. 308. 



ON THE FAUNA OF IRELAND. 371 

Order Insessores. 

Div. 3. SCANSORES. 

Fam. Picidte. 

Ireland. Great Britain. 

Picus viridis, L. 

Picus major, L. + 

,, minor, L. 

,, martius, L. 

Yunx Torquilla, L. 

Owing to the general scarcity of wood, especially old, this 
family of birds is rare. P. major only can with certainty be in- 
troduced to our catalogue, and it is but a very rare visitant. 
" Picus varius minor. Lesser Spotted Woodpecker," is given 
as one of the birds of the co. Dublin by Rutty*. In Dr. Patrick 
Brown's catalogue of the Birds of Ireland it likewise has a 
place, but was probably copied from Rutty. In Smith's Water- 
fordf appears " Picus Martis, the Woodpecker, a bird rare in 
this county :" the P. martius can hardly have been here meant. 

Picus viridis would appear to be generally distributed in 
suitable localities in Great Britain, and P. minor to be so in 
England ; P. martius is a very rare visitant. Yunx Torquilla, 
one of the summer birds of passage to England, decreases in 
numbers towards the west of that country. 

Fam. Certhiadce. 
Ireland. Great Britain. 

Certhia familiaris, L. + 

Troglodytes europseus, Cuv. -\- 

Upupa Epops, L. + 

Sitta europasa, L. 

Cert, familiaris constantly inhabits the best-wooded districts 
throughout Ireland ; Trog. europcBus is common and resident. 
Upupa Epops is a rare visitant but has been taken in all quar- 
ters of the island. 

Sitta europcBa is somewhat local in England, and towards 
the West is said to become more rare. 

Fam. CuculidcE. 
Ireland. Great Britain. 

Cuculus canorus, L. -\- 

Coccyzus americanus, Bonap. + 

The former is a regular vernal migrant to Ireland, and is 
generally diffused ; the latter has on two or three occasions 
been obtained in the counties of Cork and Dublin. 

* Vol. i. p. 302. f P. 338. 

2 b2 



372 REPORT — 1840. 

Order Insessores. 

Div. 4. FlSSIROSTRES. 

Fam. Meropid(B. 

Ireland. • Great Britain. 

Coracias garrula, L. + 

Merops Apiaster, L. + 

Both species are extremely rare and known only to have oc- 
curred on two or three occasions in Ireland. 

Fam. Halcyonid(B. 
Ireland. Great Britain. 

Alcedo Ispida, L. + 

Is diffused over suitable localities and resident. 
Fam. Hirundinidce. 
Ireland. Great Britain. 

Hinindo rastica, L. + 

„ urbica, L. + 

,, riparia, L. + 

Cypselus Apus, Flem. + 

,, alpinus, Temm. + 

The three species of Hirundo and Cyp. Ajms are regular 
vernal migrauis to Ireland, ^'yp- alpinus iias been obtained 
once off Cape Clear, and again in the county of Dublin. 
Fam. Caprimidgidce. 
Ireland. Great Britain. 

Caprimulgus eiuopseus, L. + 

A regular summer visitant to certain portions of the island 
both north and south, but very local. 

Order 3. — Rasores. 

Fam. ColumbidcB. 

Ireland. Great Britain. 

Columba Palumbus, L. + 

Columba CEnas, L. 

„ Livia, Briss. -f- 

„ Turtur, L. + 

„ migi-atoria, L. 

C. Palumbtis and C. Livia are common and resident in their 
very different places of abode. C. Turtur is an occasional 
summer visitant. 

C. CEnas is very partially distributed in England, being 
chiefly confined to the midland and eastern counties. Of C 
migratoria a single specimen, supposed to have been in a wild 
state, has been obtained in Great Britain*. 

* Phasianus Colchicus, and its var. /3 the Ring-necked, are common in many 
parts of Ireland to which they have been introduced. 



ON THE FAUNA OF IRELAND- 37o 

Fam. TetraonidcB. 
Ireland. Great Britain. 

Tetrao Tetrix, L. 
Lagopus scoticus, Selby. 4- 

Lagopus niiitus, Leach. 
Perdix cinerea, Lath. -f- 

„ Coturnix, Lath. -f- 

In the genera Tetrao and Lagopus, which in the eye of the 
sportsman if not of the naturahst are of all others the most 
attractive, we now possess but one species, the Lagopus 
scoticus. This is common to heathy tracts, from the low- 
lying bog to the mountain top throughout Ireland, and is in 
many places as abundant as in the highlands of Scotland. Of 
the Tetrao Urogallus, Smith, in his History of Cork*, ob- 
servesj that it is now found rarely in Ireland since our woods 
have been destroyed. In his Natural History of Dubhn, Rutty 
remarks, that "one of these \_T. Urogallus'] was seen in the 
county of Leitrim about the year 1710, but they have entirely 
disappeared of late, by reason of the destruction of our woodsf ." 
In the work above cited. Smith describes the T. Tetrix as 
" frequent." Mr. Templeton states that he had been in- 
formed by excellent authority, that " black game is mentioned 
in some of the old leases of the county of Down"| ; and else- 
where this bird is noticed as a native. That the species alluded 
to by Smith was the T. Tetrix would seem hardly to admit of 
doubt, as in addition to it he enumerates the Red Grouse. If 
it were really indigenous, its extinction must, I conceive, be at- 
tributed to the destruction of our native woods. The Lagopus 
mulus is not now, nor do I conceive ever was, indigenous to 
this island. There seems not to be in any part of Ireland a 
continuity of mouDtaiiis of sufficient altitude to be suited to the 
Ptarmigan's abode. Perdix cinerea is common and resident. 
P. Coturnix frequents the most highly-cultivated districts in 
summer, and within the last few years has in certain localities 
remained throughout the winter. 

Fam. StruthionidcB. 



Ireland. 


Great Britain. 





Otis Tarda, L. 


Otis Tetrax, L. 


4- 



The latter species, which is a very rare visitant to Great 
Britain, has once been obtained in Ireland, in the county of 
Wicklow a few years ago. O. Tarda is enumerated by Smith 

* 1749. f Vol. i. p. 302. 

X Magazine of Natural Historj', vol. i. new series. 



374 REPORT— 1840. 

as one of the birds of the county of Cork ; it is long since 
extinct. 

Order 4'. — Grallatores. 
Fam. Charadriadce. 

Ireland. Great Britain. 

Cursorius Isabellinus, Meyer. 

CEdicnemus crepitans, Temm. -f 

Charadrius pluvialis, L. ■\- 

„ Morinellus, L. + 

„ Hiaticula, L. + 

Charadrius minor, Meyer. 

,, Cantiacus, Lath. 

Squatarola cinerea, Cuv. + 

Vanellus cristatus, Meyer. + 

Strepsilas Interpres, Leach. + 

Arenaria Calidris, Meyer. -\- 

Haematopus Ostralegus, L. + 

In this family, Van. cristatus and Hcem. Ostralegus are com- 
mon and resident. Char, pluvialis and C. Hiaticula are com- 
mon and partially resident; the numbers of both species (certain- 
ly of the former) being much increased by an autumnal migra- 
tion from higher latitudes. Squat, cinerea, Strep. Interpres, 
and Aren. Calidris, are regular periodical visitants. (Edic. 
crepitans and Char. Morinellus very rarely visit Ireland. 

Of the Cursorius Isabellinus, four individuals have been 
obtained in England and Wales. Char, minor has a place in 
the British catalogue from a single specimen killed in Sussex. 
To the east and south-east of England only, I believe, is 
Char. Cantianus known. 

Fam. Gruidce. 

Ireland. Great Britain. 

Grus cinerea, Bechst. 

In his History of Cork, Smith states that " this bird was 
seen in this country during the remarkable frost of 1739." 

Fam. Ardeidce. 

Ireland. Great Britain. 

Ardea cinerea, Lath. -f- 

,, purpurea, L. -|- 

Ardea alba, L. 

,, Garzetta, L. + 

,, russata, Wagler. 

„ Ralloides, Scop. 

Botaurus stellaris, Steph. + 

Botaurus Mokoho, FieiU. 

„ minutus, Selby. + 

Nycticorax europaeus, Steph. + 



ON THE FAUNA OF IRELAND. 



375 



Ireland. Great Britain. 

Ciconia alba, Ray. 

„ nigra, Ray. 

Platalea Leucorodia, L. + 

Ibis Falcinellus, Temm. + 

In this family, the Ardea cinerea only is common and resi- 
dent; Botaurus stellaris is, in consequence of the improve- 
ment of the bogs, becoming gradually scarcer, and, as a resi- 
dent species, is confined to few localities. Bot. minutus, Nyct. 
europceus, Plat. Leucorodia, Ibis Falcinellus, are rare visit- 
ants. Ardea purpurea and A. Garzetta have each been once 
obtained ; of the latter species, one or two other examples in 
addition to that alluded to*, are said to have occurred on the 
southern coast. 

The six British species of the Ardeidce which are desiderata 
in Ireland, are, with the exception of Ciconia alba, very rare 
visitants ; three of them, indeed, are with certainty placed in 
the catalogue from their occurrence each in a single instance. 

Fam. Scolopacidce. 



Ireland. 




Great Britain. 


Numenius arquata, Lath. 




+ 


„ Phseopus, Lath, 




+ 


Totanus fuscus, Leisl. 




+ 


„ Calidris, Bechst. 




+ 


„ Ochropus, Temm. 




+ 


„ Glareola, Temm. {2) 




+ 


„ Hypoleucos, Temm. 




+ 


„ Glottis, Bechst. 




+ 


Recurvirostra Avocetta, L. 




4- 


Himantopus melanopterus, Temm. 




+ 


Limosa melanura, Leisl. 




+ 


„ rufa, Briss. 




+ 


Scolopax Rusticola, L. 




+ 


„ Sabini, Vigors. 




+ 


„ major, Gmel. (?) 




+ 


„ Gallinago, L. 




+ 


„ Gallinula, L. 




+ 





Macroramphus griseus, Leach. 


Machetes pugnax, Cuv. 




+ 


Tringa subarquata, Temm. 




+ 


„ variabilis, Meyer. 




+ 





Tringa 


pectoralis, Bonap. 


" maritima, Brunei . 




+ 





jj 


Temminckii, Leisl. 


„ minuta, Leisl. 




+ 


,, Canutus, L. 




+ 





J) 


rufescens, Vieill. 





Lobipe 


s hyperboreus, Steph. 


Phalaropus lobatus, Flem. 




+ 



See Tenipleton in Magazine of Natural History, vol. i. new series. 



376 RtPORT — 1840. 

The word " resident," in the sense in which it has hitherto 
been used, will not apply to any of the Sclopacidce. The 
species of which a portion breed in Ireland, and are common 
at all seasons, are Num. arquata, Tot. Calidris, Scol. Gctlli- 
nago, and Trin. variabilis. Tot. Hypoleucos is a regular 
summer visitant ; at the same season T. Ochropns has occa- 
sionally been met with, and very rarely T. Glareola^l The 
regular autumnal migrants are Num. Phcsopus, Tot. Glottis, 
Lim. rttfa, Machetes pugnax, Trin. subargtiataf, T.minuta^, 
T. Camitus ; and to these probably Lim. melanura might with 
propriety be added. In the North of Ireland these species are 
met with for a longer or shorter period during autumn, and 
generally move southward on the approach of winter : to this 
there are, however, occasional exceptions, in some I'emaining 
behind ; to T. Canutus and T, Glottis this more especially 
applies. Num. P/iceojms is, in conseqvience of being in large 
flocks, much better known upon our coasts in spring when 
migrating northwards, than in the autumn, when it appears 
only in small numbers. Scol. Rusticola and S. Gallinula come 
from more northern latitudes to abide the winter ; the former 
has of late years bred in various parts of Ireland |. Scol. Sa- 
hini, Trin. maritima, and Phal. lohatus, have on several occa- 
sions been obtained ; T. maritima is probably a regular winter 
visitant. Recur. Avocetta and Him. melanopterus have twice 
been noticed. Tot.fuscus is on record, from a single example 
having occurred : this species may have escaped notice from 
its general similarity to the common Tot. Calidris. Scol. major 
should not perhaps be included even with a mark of doubt, 
as I have not seen any example of it, killed in Ireland, but 
sportsmen have described birds to me that can hardly be any 
other, and have correctly remarked on the peculiarity of habits 
in which they differed from the Scol. Gallinago. 

Of our desiderata in the Scolopacidce, Tr. pectoralis has 
once, and Tr. rufescens twice, been obtained in England ; 
Macr. griseus is a *' very rare," and Tr. Temminclcii an " oc- 
casional visitant" to that country. Lohipes hyperboreus is in 
Great Britain chiefly confined to the more northern isles and 
coasts of Scotland. 

Fani. RallidcE. 
Ireland. Great Britain. 

Glaveola Fratincola, Leach. 

Rallus acjnaticus, L. -\- 

* See Annals of Natural History, vol. v. p. 8. 

t Ibid., vol. iv. p. 285. 

X Annals of Natural History, vol. ii. 



ON THE FAUNA Ol' IRELAND. 377 

Ireland. Great Britain. 

Crex pratensis, Bechst. + 

„ Porzana, Selhy. + 

Crex Baillonii, Selhy. 

,, pusilla, Selby. 

Gallinula Chloropus, Lcth. + 

Fulica atra, L. + 

R. aquatictis and the two last are resident and common, as 
the species ordinarily are in other countries. Crex pratensis 
is a regular summer visitant, and abundant ; C. Porzana a 
species of occasional occurrence at the same season. 

Of Glareola Pratincola, four individuals are on record as 
British. Crex Baillonii and C. pusilla are very rare visitants 
to England. 

Order 5. — Natatores. 
Fam. AnatidcB. 

Sub-Fam. Anserina. 



Ireland. 


Great Britain. 


Anser palustris, Flem. 


+ 


,, ferns, Flem. 


+ 


„ Ei-ythropus, Flem. 


+ 


„ Bernicla, Flem. 


-H 


„ Brenta, Flem. 


+ 





Anser ruficollis, Pall. 





Plectopterus Gambensis, Staph 


Cygnus ferus, Ray. 


+ 


„ Bewickii, Yarr. 


+ 



A. ferus [A. Segetum, Steph.), A. Erythropus {A. albifrons, 
Steph.), A. Bernicla and Jl. Brenta are regular winter visitants 
to Ireland, the two last, but more especially A. Brenta, being 
in great numbers in their very different places of abode. A. 
palustris {A. ferus, Steph.) is much more rare than the two 
first mentioned : at one period it bred in this country, but has 
long since ceased to do so. 

Wild Swans are seen every winter in some parts of Ireland, 
but it cannot be positively stated of either C ferus or C. 
Bewickii, that it is a regular winter visitant ; that one or both 
may be so considered is a fair inference, from the same lakes 
being annually visited by " wild Swans." Of both species I 
have seen examples, which were obtained in the north, east, 
and west of the island ; C. Bewickii is of much more frequent 
occurrence than C. ferus. The Egyptian Goose {Anser 
cBgyptiacus) and Canada Goose {Anser Canadensis) have at 
different times been shot on the Irish coast : the former species 
had doubtless escaped from ponds ; the latter, too, had in all 
probability done so. 



378 



REPORT — 1840. 



A. ruficollis is a very rare visitant to England. A. Gamben- 
sis has been but once obtained, and whether the individual so 
recorded was a wild bird is very questionable, as the species 
does not appear to have been met with on the European con- 
tinent. 

Fam. Anatidce. 



Sub-Fam. 


^natiiKB. 






Ireland. 




Great Britain. 


Tadorna Vulpanser, Flem. 






+ 





Tadorna 


rutila 


Steph. 


Spatliulea clypeata, Flem. 






+ 


Chauliodus Strepera, Sw. 






+ 


Anas Boschas, L. 






+ 


Querquedula acuta, Selby. 






+ 


„ Crecca, Steph. 






+ 


„ Circia, Steph. 






+ 





Querquedula glocitans, Vigors 


Mareca Penelope, Selby. 






+ 



Three species, T. Vulpanser, A. Boschas, and Q. Crecca, 
may be called resident from their breeding in Ireland and 
being met witb at all seasons ; but of the numbers of the two 
last which are here in winter, but a small proportion is bred in 
the country. Spat, clypeata is most probably indigenous, as 
in England. It has occurred in Ireland in May, and I once 
obtained an adult female, shot in July. Querq. acuta and Mar. 
Penelope are regular winter visitants. Chaul. Strepera and 
Querq. Circia [A. Querquedula) are of rare occurrence at the 
same season; of the latter I have not myself seen a duly-authen- 
ticated Irish example ; it is noticed in Tighe's Kilkenny, and 
in a catalogue of the Birds of Dublin supplied me by Mr. R. 
Ball. 

Tad. rutila and Querq. glocitans are extremely rare visit- 
ants to England. 

Fam. AnatidcB. 

Sub-Fam. Fuligulina. 



Ireland. 


Great Britain. 


Somateria mollissima, Leach. 


+ 


„ spectabilis, Leach. 


+ 


Oidemia fusca, Flem. 


+ 


„ nigra, Flem. 


+ 





Fuligula rufina, Steph. 


Fulig