J6:,^.r:^.^. /.;,.../. NOTICES PEOCBBDINGS MEETINGS OF THE MEMBERS ROYAL INSTITUTION OF GREAT BRITAIN ABSTRACTS OF THE DISCOURSES DELIVERED AT THE EVENING MEETINGS VOLUME XXII 1917— 19iy LONDON PRINTED BY WILLIAM CLOWES AND SONS LIMITED 1922 CONTENTS. 1917. I'M 7. PAGK .I;m:. r.). — Silt Ja.mks Dkwai.', Soup l)nl»l)les of Long Duration ... ... ... ... .. ... 171^ „ 26. — (iiiii'.Kirr Muim{.av~ F^jn'cnrcan I'hilosopliy ... l I'd . 2. — Sill (liiAiUiKS S. Si[Ki:iiiX(}TON — Recent Physio- loU7 and tlio AVai' 1 '2<' „ 7. — Sir Bovertox Redwood— The Romance of Petro- leum ... ... ... ... ... ... :]2d July 1. — General Meeting ... ... ... ... ... :)■[[) Xov. 4. — General Meeting ... ... ... ... ... :>.51 Dec. 2. — General Meeting ... ... ... ... ... 3r).> 1919. 1919. Jan. 17. — Sir James Dewar — Liquid Oxygen in ^Yarfare ... iVJl „ 24. — LiEUT.-CoL. Andrew Balfour— One Side of War 4(t7 ,, 31. — H. H. Turner— Giant Suns 411 Vv\) 3. — General Meeting ... ... ... ... ... 421 „ 7. — J. G. Adami — Medical Research in its relationship to the War 424 ., 14. — Cargill G. Knott — Earthquake Waves and the Interior of the Earth „ 21. — A. T. Hare — Clock Escapements ,, 28. — Sir OiiivEU Lodge — Ether and Matter ... March 3, — General Meeting 7. — H. C. H. Carpenter — The Hardeninu- of Steel 440 id 4.".4 478. 481 14. — Sir Arthur Keith — The Organ of Hearin.u' from a New Point of View aOfi CONTENTS Vll 1919. PAGE Mar. 21. — W. W. AVatts — Fossil Landscapes ... ... 590 28.— Sir John H. A. Macdonald— The Air Road ... 5lo April 4. — Frederic Harrison — History of the City of Constantinople ... ... ... ... ... r>l;5 „ 7. — General Meeting ... ... ... ... ... :)15 ., 11. — Sir J. J. Thomson — Piezo Electricity and its Applications ... ... .. ... ... .■)9() May 1. — Annual Meeting ... ... ... ... ... .")1'.J ,, 2. — John W. Nicholson — Energy Distribution in Spectra ... ... ... ... ... ... ')20 „ 5. — General Meeting ... ... ... ... ... .")2)s "May 9 — Sir George Macartney— Chinese Turkestan : Past and Present... ... ... ... ... :):\2 16.— Sir Sidney F. Harder — Sabantarctic Whales and Whaling ... ... ... ... ... r>;3.") ,, 23. — Sir Alexander C. Mackenzie — Hubert Hastings Parry ... ... ... ... ... ... 510 ,, 30.— Sir John Rose Bradford — A "Filter-passing" Virus in Certain Diseases ... ... ... 548 June 2. — General Meeting ... ... ... ... ... 561 6.^ — Sir Ernest Rutherford — Atomic Projectiles and Lio-ht Atoms ... ... ... ... 565 July. 7. — General Meeting Xov. 3. — General Meeting Dec. 1. — General Meeting Index— Vol. XXII 574 579 585 621 PLATES. PAGE Experimenial Phonetics (Figs. 6-10) ... 12, 13, 14 Vibrations (Figs. 2, 4, 5) 249, 255, 257 Internal Ballistics (Fig. 2) 308 Liquid Films (Figs. 3, 3, 7, 8, 23, 24) 364, 365, 371, 383 PROCEEDINGS OF THE Royal Institution of Great Britain Vol. XXII.— Part I. No. Ill 1917. Jan. 19. Jan. 26. Feb, 2. Feb. 5. Feb. 9. Feb. 16. Feb. 23. March 2. March 5. March 9. March 16. March 23. March 30. April 2. April 20. April 27. May 1. May 4. May 7. May 11. May 18. May 25. June 1. June 4, June 8. July 2. Nov. 5. Dec. 3. PA6B Professor Sir James Dewar — Soap Bubbles of Long Duration 179 Professor Gilbert Murray — Epicurean Philosophy ... 1 Professor C. sT^ Sherrington — Recent Physiology and the War 1 General Meeting 4 Daniel Jones — Experimental Phonetics and its Utility to the Linguist (Illustrated) * 8 Very Rev. H. Hensley Henson — Authors' Dedications in the XVIIth Century 19 Discourse not delivered 20 Charles F. Cross — Cellulose and Chemical Industry (1866- 1916) 21 General Meeting ^. 27 Sir Almroth Wright — The Treatment of War Wounds ... 30 Sir John Stirling Maxwell — Scientific Forestry for the United Kingdom 63 Edward Clodd — Magic in Names 75 Professor J. H. Jeans — Recent Developments of Molecular Physics 77 General IVIeeting 87 Professor R. H. Biffen — The Future of Wheat-Growing in England 90 J. DuNDAS Grant— The Organs of Hearing in Relation to War 91 Annual Meeting 99 H. WiCKHAM Steed— Some Guarantees of Liberty 101 General Meeting 112 Professor John Joly — Radioactive Haloes 115 Professor Frederick Soddy — The Complexity of the Chemical Elements ... ■ 117 J. Barcroft — Breathlessness 139 J. H. Balfour Browne —The Brontes : a Hundred Years After 140 General Meeting 162 Professor Sib J. J. Thomson — Industrial Applications of Electrons 175 General Meeting 165 General Meeting 167 General Meeting 172 ALBEMAKLE STEEET, LONDON, W.l October 1919 Royal Ixsini tiox of Great Britain. WEEKLY EVENING MEETING, Friday, January 26, 1917. His Geace the Duke of Northumberland, K.G. D.C.L. F.K.S., President, in tlie Chair. Professor Gilbert Murray, M.A. LL.D. Litt.D. F.B.A. Epicurean Philoso(3hy. [No Abstract.] WEEKLY EVENING MEETIN Friday, February 2, 1917. Sir James Reid, Bart., G.C.V.O. K.C.B. M.D. LL.D., Vice-President, in the Chair. Professor Charles S. Sherrington, M.D. LL.D. D.Sc. F.R.S., FuUerian Professor of Physiology. Recent Physiology and the War. This theme, kindly suggested by Professor Sir James Dewar, is sufficiently large to preclude more than a succinct treatment of some outstanding points in the time permissible in a single lecture. But these points are of considerable interest and have a more than fleeting importance. The first is that of fatigue, its measurement and incidence in factory employees. The indices taken have been speed of output and quantity of output by groups of \Yorkpeople working under the conditions of a munitions factory. An inference of practical value drawn from the observations is that when the number of working hours per week was reduced from sixty-two to fifty-six the output actually increased. The reduction of the length of the working day by one hour per diem gave a rise of the total output of the week from an amount stated numerically as 6150 to an amount expressed as 6759. The output per hour increased 22 per cent. The kind of work in this case was " heavy," namely, deep screw-cutting by hand. Vol. XXII. (No. 111)^ ' b 2 Professor Charles S. Sherrington [Feb. 2, In another case, that of 200 women tui-ning ahiminium fuse- bodies, the reduction of the working hours per week from (>8-2 to 60 notably increased the total output, and of course still more the rate of output. From these and other examples the lesson seems to be that there is for manual labour a certain length of working week, or working month, best suited for satisfactory production in permanence. The length varies with the class of the manual work. If a good efficiency is to be maintained in the factory this " most favourable " length of working month has to be followed. Before that it has to be found out and measured. The next point raised was the influence of alcohol on the workers' output. The question has at present been attacked only in the laboratory so far as physiology is concerned. Physiological experiment shows that even a large single dose of alcohol — e.g. 40 cc. — has little or no effect upon the muscles }^er se, but that it does impair the working of the nervous system which actuates the muscles. A suitable test in respect of tbe simplicity of the nervous centres involved in it is the knee-jerk. This is a familiar reaction to every physician ; it is a reflex act, the spinal centre for which has been thoroughly investigated. The effect of a single dose of alcohol of 30 cc. quantity diUited with 120 cc. of water is to diminish and render sluggish the knee-jerk ; the speed of the response is sometimes decreased by 9*6 per cent., the ampHtude of the response lessened by 48 • 9 per cent. The greatest impairment of the reaction was noted about one hour after the dose. Another test of the effect of alcohol on the musculo-nervous actions was furnished by a very simple voluntary act. The person subjected to the experiment was required to move one finger to and fro, that is, to bend and straighten the finger alternately, as rapidly as possible. The rate of movement was examined before and after taking a dose of :')0 cc. alcohol diluted as above. This dose impaired the rate at which the oscillatory movement of the fluger could be performed. The rate was diminished an hour after the dose by 8 • 9 per cent. Such a movement is not well calculated to test that form of skill which consists in precision. Reasons were adduced for thinking that precision of movement is that aspect of a muscular act which will be most detrimentally interfered with by alcohol. The testing of alcohol effect by the ergograph seems to show that a moderate dose, say 30 cc. of alcohol, in a person accustomed to moderate use of alcohol, does not appreciably impair the power of the movement nor its resistance to fatigue. But the movements chosen as suitable for ergographic record are such as give little opportunity for the exhibi- tion of precision or of skill of any kind. The next point dealt with was the attempt to devise some fluid which can be injected to counteract the effect of severe loss of blood in the wounded. The properties desirable for the required fluid 1917] on Recent Physiology and the War 3 were sliown to l)e : liarmlessness in respect of avoidance of causing slotting in the circulation ; restoration of the volume of the fluid in the circulation ; maintenance of the due degree of viscosity of the circulating fluid, since on that factor depends the arterial and capillary pressure ; and, finally, preservation of the balance between the osmotic pressure of the fluid inside the blood-vessels and outside in the tissues. It was shown that considerable success had been reached in this problem by the experiments of Professor Bayliss and others. A final point dealt with was the treatment of tetanus by adminis- tration of " anti-tetanus serum." This serum is obtained from the blood of horses which have been subjected to gradually-increasing doses of tetanus-toxin, the poison produced by the tetanus-bacillus. The high efficiency of this anti-toxic serum when used as a prophylactic was first demonstrated on man on a large scale by its employment in the first autumn of this war. Curves illustrating the statistics were shown. The severe outbreak of tetanus which ensued in the troops at the outset of the campaign was checked and practically stopped almost instantaneously by the orders that every wounded man, as soon as possible after being wounded, that is to say, at the first field casualty-station, should receive a small injection of anti- tetanus serum from the immunized horse. But the efficacy of the serum when once signs of tetanus have appeared in the patient is far less satisfactory. The remainder of the Lecture was devoted to discussion of why this should be, and in what ways the difficulty may be, at least in part, overcome. [C. S. S.] B 2 General Monthly Meeting [Feb. 5^ GENERAL MONTHLY MEETING, Moil day, February 5, 1917. His Grace the Duke of Northujiberland, K.G. P.O. F.R.S.,. President, in the Chair. E. Arthur Ashcroft, T. Radford Thomson, Charles F. Cross, were elected Members. Report from the Gommittee of Managers to the Memders. That the Members be informed that the IManagers, as Trustees, after having^ taken the best advice, have already invested in War Stock as much as the available Funds permit them to do, and that they are about to transfer to the Treasury Authorities the Canadian Stock invested in the name of the Institution. Facts for the Members. — During the years 1915-16 the following Sums- have already been invested in the War Loan : — The Royal Institution. ^ ,,_ ^y_ War Loan Stock 4J % 144 2 9 Exchequer Bonds 5 % 1000 0 0 The Davy Faraday Research Laboratory. War Loan Stock 3J% 1108 4 7 ditto 41% 527 11 6 Exchequer Bonds 5% 500 0 0 Total £3279 18 10 The Managers propose further to invest from the General Funds in the War Loan the Sum of £1000, and £500 from the Account of the Davy Faraday Research Laboratory. The Managers also have deposited with the Treasury Authorities, under the provision of Scheme B, £3149 5s. 9cl. Canada 4% Stock. The Presents received since the last Meeting were laid on the taljle, and the thanks of the Members returned for the same, viz. :— FROM The Secretary of State for India — Memoirs of Department of Agriculture : Chemical Series, Vol. IV. No. 6. 8vo. 1916. Pusa : Agricultural Kescarch Institute, l^ulletin, Nos. 62, 63 & 67 ; Keporb of Agricultural iiesearch Institute, 1915-10. 8vo. 1916. Accademia dci Lincci, Roma — Kencliconti : Classe di Scienze Morali, Storiche e Filologiche, Scrie Quinta, Vol. XXV. Fasc. 5-6. Svo. 1916. Atti, Serie Quinta, Kendiconti : Classe de Scienze Fisiche, Mathematiche e Naturali, Vol. XXV. 2" Semestre, Fasc. 8-12. 8vo. 1916. 1917] General Monthly Meeting 5 Accountants, Association of — Journal for Dec. 191G-Jan. 1917. 8vo. Aeronautical Institute of Great Britain — " Air," Vol. I. No. 1. 8vo. 1916. American Chemical Society — Journal for Dec. 1916-Jan. 1917. 8vo. Journal of Industrial and Engineering Chemistry for Dec. 1916-Jan. 1917. 8vo. American Geographical Socic^/y— Geographical Review for Dec. 1916. 8vo. American Journal of Physiology -^o\.lslAl.^o^. 1-2. 8vo. 1917. - American PI lilosopllical .S'ocit'^?/— Proceedings, Vol. LV. No. 7. 8vo. 1916. Asiatic Society, i2o|/aZ— -Journal for Jan. 1917. 8vo. Astronomical Society, i?o?/aZ— Monthly Notices, Vol. LXXVII. No. 1. 8vo. 1916. Bankers, Institute o/— Journal, Jan. 1917, Vol. XXXVIII. Part 1 ; Feb. 1917, Vol, XXXVIII. Part 2. 8vo. Basel — Verhandlungen der Naturforschenden Gesellschaft in Basel, Band XXVII. 8vo. 1916. Bevan, Rev. J. O., M.A. F.G.S. M.R.I, {the Authoi-)— The Towns of Roman Britain. 8vo. 1917. Bhownaggree, Sir Mancherjee M., K.C.I. E. (the .4«f/ior)— The Verdict of India. 12mo. 1916. Birmingham and Midland Institute — Report of Council for 1916. British Architects, Royal Institute of — Journal, Third Series, Vol. XXIV. Nos. 3-5. 4to. 1917. British Astronomical Association — Journal, Vol. XXVII. No. 2. 8vo. 1916. Brooklyn Institute of Arts and Sciences, The Museum o/— Science Bulletin, Vol. II. No. 6. 8vo. 1916. Cambridge Philosophical Society — Pi oceedings. Vol. XIX. Part 1. 8vo. 1917. Canada, Department of Mines — Mines Branch: An Investigation of the Coals of Canada. 8vo. 1915. Museum Bulletin, Nos. 23-24. Canada, Royal Society o/— Transactions, Third Series, Vol. X. Sept. 1916. 8vo. Carnegie Institution — Contributions from Mount Wilson Solar Observatory, Nos. 115-123. 8vo. 1916. Chemical Industry, Society o/— Journal, Vol. XXXV. Nos. 22-23. 8vo. 1916 ; Vol. XXXVI. No. 1. 8vo. 1917. Chemical Society — Journal for Dec. 1916-Jan. 1917. Chemistry, Institute of — Proceedings, Part 4. 1916. 8vo. Chicago, Field Museum of Natural History — Publications : Ornithological, Vol. I. No. 10; Zoological, Vol. X. No. 14; Botanical, Vol. II. No. 11; Geological, Vol. III. No. 10 ; Report Series, Vol. V. No. 1. 8vo. 1916. Comiti cV Administration de France, Maroc — Revue Mensuelle, No, 1. 4to. 1816. Consolo, Enrico [Banca Commerciale Italiana) — The War in Italy. Vols. I.-III. 4to. 1916. Cutlers, The Worshipful Company o/— History of the Cutlers' Company of London. By Charles Welch, F.S.A. Vol. I. 8vo. 1916. Devonshire Association — Report and Transactions, Vol. XLVIII. July 1916. 8vo. 1916. East India Association — Journal, New Series, Vol. VIII. No. 1. 8vo. 1917. Editors — x\eronautical Journal for Oct. -Dec. 1916. 8vo. Amateur Photographer for Dec. 1916. 4to. American Journal of Science for Dec. 1916-Jan. 1917. 8vo. Athenaeum for Dec. 1916-Jan. 1917. 4to. Author for Dec. 1916-Jan. 1917. 8vo. Chemical News for Dec. 1916-Jan. 1917. loo. Chemist and Druggist for Dec. 1916-Jan. 1917. 8vo. Church Gazette for Dec. 1916-Jan. 1917. 8vo. Concrete for Dec. 1916-Jan. 1917. 8vo. Dyer and Calico Printer for Dec. 1916-Jan. 1917. 4to. Electrical Engineering for Dec. 1916-Jan. 1917. 4to. Electrical Industries for Dec. 1916-Jan. 1917. 4to. Electrical Review for Dec. 1916^Jan. 1917. 4to. 6 General Monthly Meeting [Feb. 5, Editors — continued Electrical Times for Dec. 1916-Jan. 1917. 4to. Electricity for Dec. 1916-Jan. 1917. 8vo. Electric Vehicle for Dec. 1916. 8vo. Engineer for Dec. 1916-Jan. 1917. fol. Engineering for Dec. 1916-Jan. 1917. fol. Perro-Concrete for Dec. 1916-Jan. 1917. 8vo. General Electric Review for Dec. 1916-Jan. 1917. Svo. Horological Journal for Dec. 1916-Jan. 1917. Svo. Illuminating Engineer for Dec. 1916. Svo. Journal of Physical Chemistry for Dec. 1916. Svo. Journal of the British Dental Association for Dec. 1916-Jan. 1917. Svo. Junior Mechanics for Dec. 1916-Jan. 1917. Svo. LiSiW Journal for Dec. 1916-Jan. 1917. Svo. Marine Engineer for Dec. 1916-Jan. 1917. Svo. Marine Magazine for Dec. 1916-Jan. 1917. 4to. Model Engineer for Dec. 1916-Jan. 1917. Svo. Musical Times for Dec. 1916-Jan. 1917. Svo. Nature for Dec. 1916-Jan. 1917. ito. New Church Magazine for Dec. 1916-Jan. 1917.. Svo. Page's Weekly for Dec. 1916-Jan. 1917. Svo. Physical Review for Dec. 1916. Svo. Power for Dec. 1916-Jan. 1917. Svo. Power User for Dec. 1916-Jan. 1917. Svo. Russian Co-operator for Dec. 1916. Svo. Science Abstracts for Dec. 1916-Jan. 1917. Svo. Tcheque, La Nation, for Dec. 1916. Svo. War and Peace for Dec. 1916-Jan. 1917. Svo. Wireless World for Dec. 1916-Jan. 1917, Svo. Zoophilist for Dec. 1916-Jan. 1917. Svo. Electrical Engineers, Institution 0/-V0I. LV. Nos. 261-262. Svo. 1916. Faraday 1/owse— Journal, Vol. VII. No. 2. Svo. 1917. Florence Biblioteca Nazionale Centrale — Bollettino, Nos. 192-193. Svo. 1917. Franklin Institute— J ouvn&\, Vol. CLXXXII. No. 6. Svo. 1916. Geographical Society, Royal — Journal, Vol. XL VIII. No. 6. Svo. 1916 ; Vol. XLIX. Nos. 1-2. Svo. 1917. Geological Society of London — Quarterly Journal, Vol. LXXI. Part 4. Svo. 1917. Harvard University — Contributions from the Jefierson Physical Laboratory for the Year 1915, Vol. XII. Svo. Imperial Jws^i^w^e— Bulletin, July-Sept. 1916. Svo. Jones, Daniel, M.A. M.R.I, {the Atithor) — A Sechuana Reader. Svo. 1916. Jordan, William Leightmi, F.R.G.S. M.R.I, {the Author) — The Elements. Vols. I. & II. Svo. 1S66-67. Jugoslav Committee — Southern Slav Bulletin, Nos. 25-27. 1916. Kyoto Imperial University — Memoirs of College of Engineering, Vol. I. Nos. 6-7. 4to. 1916. Memoirs of College of Science, Vol. I. Nos. S-10. 1916. Svo. Literature, Royal Society of — Transactions, Vol. XXXIV. Svo. 1916. Report and List of Fellows, 1916. Svo. London County Council — Gazette for Dec. 1916-Jan. 1917. 4to. Manchester Steam J'sers' Association — Boiler Explosions Acts, 1S82 & 1S90. Reports, Nos. 2327-2.3S7. 4to. 1916. Meteorological 0^'cc— Monthly Weather Reports for Nov.-Dec. 1916. 4to. Weekly Weather Reports for Dec. 1916-Jan. 1917. 4to. Daily Readings for Oct. 1916. 4to. Geographical Journal for Jan. -Feb. 1915. 4to. Microscopical Society, Royal — Journal, Dec. 1916. Svo. Milford, Humphrey {Oxford University Press) — Oxford University Press General Catalogue. Svo. 1916. 1917] General Monthly Meeting 7 Montpellier, Academie des Sciences — Bulletin, Nos. 6-12. 8vo. 1916. Musical Association — Proceedings, Forty-Second Session, 1915-16. 8vo. 1916. Neiv York, Society for Experimental Biology — Proceedings, Vol. XIV. No. 1. 8vo. 1916. Neiv Zealand, High Commissioner for — Fa,tent Of&ce Journal, Dec. 1916-Jan. 1917. 8vo. Nova Scotian Institute of Science — Proceedings and Transactions of the, Vol. XIV. Part 2. 8vo. 1916. Numisynatic Society, Royal — Numismatic Chronicle, Fourth Series, Part 3, No. 63. 1916. 8vo. Paris, Societe d" Encouragement pour V Industrie Nationale — Bulletin for Sept.-Dec. 1916. 4to. PeriL, Corps of Mining Engineers — Bu.letin, No. 82. 8vo. 1916. Pharmaceutical Society of G^-eat Britain — Journal for Dec. 1916-Jan. 1917. 8vo. The Calendar, 1917. 8vo. Photographic Society, Royal — Journal, Vol. LVII. No. 1. 8vo. 1917. Physical Society of London — Proceedings, Vol. XXIX. Part 1, Dec. 1916. 8vo. Post OMce Electrical .Engineers, Institution o/— Nos. 68-69. 8vo. 1916. Journal, Vol. IX. Part 4, Jan. 1917. Quekett Microscopical CZz^fe— Journal, Series 2, Vol. XIII. No. 79. 1916. 8vo. Rockefeller Institute for Medical Research— Stndieii, Vol. CCXXIV. 8vo. 1916. Rome, Ministry of Public Works — Giornale del Genio Civile for July-Sept. 1916. 8vo. Royal Colonial Institute— United. Empire, Vol. VII. No. 12. 8vo. 1916; Vol. VIII. No. 1. 8vo. 1917. Royal Engineers' Institute — Journal, Vol. XXIV. No. 6. 8vo. 1916 ; Vol. XXV. Nos. 1-2. 8vo. 1917. Royal Society o/ ^rfs— Journal for Dec. 19L6-Jan. 1917. 8vo. Royal Society of London — Proceedings, Series A, Vol. XCII. Nos. 643-645 ; Vol. XCIII. No. 646 ; Series B, Vol. LXXXIX. Nos. 616-617. 8vo. 1916. Transactions, Series B, Vol. CCVIII. No. 852. 4to. 1917; Series A, Vol. CCXVII. No. 551. 4to. 1917. Sanitary Institute, i?o?/ai— Journal, Vol. XXXVII. No. 4, Dec. 1916. Svo. Scottish Geographical Society, Royal — Scottish Geographical Magazine, Vol. XXXII. No. 12. Svo. 1916; Vol. XXXIII. Nos. 1-2. Svo. Scottish Meteorological Sociei?/— Journal, Third Series, Vol. XVII. No. 33 Svo. 1916. Selborne Society — Selborne Magazine for Jan. 1917. Svo. Smithsonian Institution — Miscellaneous Collections : Vol. LXVI. No. 11. Svo. 1916. Societd degli Spettroscopisti Italiani — Memorie, Serie 2, Vol. V. Disp. 12. 4to. 1916. Sweden, Royal Academy of Sciences — Meddelanden, Band III. Heft 3 ; Arkiv., Kemi, Band VI. Heft 2-3; Matematik, Band IX. Heft 1-3; Zoologi, Band X. Heft 1-3 ; Botanik, Band XIV. Heft 3. Svo. 1916. Arsbok, 1916 ; Handlingar, Band LV. Nos. 1-6. 4to. 1916. Tohoku Mathematical Journal— Yol. X. No. 3, Oct. 1916. Svo. Science Reports, Vol. V. No. 5. Svo. 1916. Tolley, Chas. H., A.C.I. S. {the Author)— Fd.m^'hlei on Income Tax, 1916-17. United Service Institution, Royal — Journal for Dec. 1916. Svo. United States Department of Agriculture — Journal of Agricultural Research, Vol. VII. Nos. 8-12. Svo. 1916 ; Vol. VIII. Nos. 1-3. 1917. Svo. Experiment Station Record, Vol. XXXV. Nos. 6-8. Svo. 1916. United States Department of Commerce and Labour — Bulletin of Bureau of Standards, Vol. XII. No. 4 ; Vol. XIII. Nos. 1-2. Svo. 1916. United States Patent Oj^ce— Official Gazette, Vol. CCXXXIV. No. 1, Dec. 1916. Svo. 1917. Zoological Society of London — Proceedings, Part 4, Dec. 1916. Svo. 1916. Mr. Daniel Jones [Feb. 9, WEEKLY EVENING MEETING, Friday, February 9, 1917. The Right Hox. Lord Raylekih, O.M. P.C. D.C.L. F.R.S., in the Chair. Daniel Joxes, M.A. M.R.I. Experimental Phonetics and its Utility to the Linguist. The art of speaking a foreign language demands (among other things) an ability to perform all kinds of difficult movements with the tongue and other parts of the speech-mechanism. Such ability may be acquired by the learner, if he is provided with precise instructions as to what he must do. It is the function of the phonetician to supply these instructions. Instructions as to how to pronounce must, in order to be efficacious, be based on accurate analysis of the pronunciation. Many of the facts of pronunciation can be ascertained by direct observation (by auditive, visual, tactile, and muscular sensation) on the part of those who have a specially-trained ear and a highly-developed control over their vocal organs. These methods are extremely important, and no satisfactory analysis of a language can be made without them. Other methods, however, may be used to supplement these, namely mechanical analysis by means of specially-designed apparatus. Analysis of this kind constitutes the branch of phonetics known as experimental phonetics. It is these mechanical aids to analysis which form the subject of the present discourse. It will be well to give first a few examples, to show how informa- tion regarding ton{/i(e-positio7is may be ascertained experimentally. One way of getting information is that known as Falatonraphy. It consists in using a special kind of artificial palate, in order to find out what parts of the roof of the mouth are touched by tiie tongue in the production of different speech-sounds. The requirements of this special type of artificial palate are that it should be very thin, should fit very accurately, should be dark- coloured, and should cover the whole of the hard palate, alveolars, and the under-side of the upper front teeth. Such palates may be made of vulcanite, or metal, or other substances. When the palate is to be used, it is dusted over with powdered chalk ; it is then inserted into the mouth ; the sound to be studied is pronounced, and the palate is taken out. It will be found that the chalk has been removed by the tongue at every point which the 1917] on Experimental Phonetics 9 tongue has touched in articulating the sound. So the areas touched by the tongue appear dark, while the parts of the palate which are not touched remain white. The shapes of the dark areas may l)e recorded by photography if desired, but it is generally sufficiently accurate, and a good deal more convenient, simply to copy the dark areas on to a previously- prepared outline diagram of the palate. (The result is, of course, a projection of the true shape.) The finished diagrams are called palatogrcmis. Palatograms will be found to corroborate observations of tongue-positions made by other methods. [Numerous examples of palatograms were shown on the screen ; Figs. 1 and 2 are specimens.] Fig. 1. Fig. 2. Palatogram of s. Palatogeam of the English Sound OF sh. We will now turn to methods of ascertaining the shapes assumed by the tongue in the articulation of speech-sounds, and more particu- larly the shapes of a section of the tongue down the mesial line, and their relations to the centre-line of the palate. One method of ascertaining these shapes was invented by Dr. E. A. Meyer, of Stockholm. It consists in using an artificial palate dow^n the middle line of which are fixed some lead threads which hang vertically. These threads are of such a thickness that the pressure from the tongue will bend them when a speech-sound is produced ; but they are strong enough to remain in the position into which they are pushed. So that if the palate is taken out of the mouth after pronouncing a speech-sound, the lead wires show the outline of the tongue-position compared with that of the palate. There is a means of transferring these outlines to paper. A second apparatus for obtaining similar results is the " mouth- measurer" invented by H. W. Atkinson.* There is a tube of the shape ACB, shown in Fig. 3, and inside the tube is a wire which can * Obtainable from H. W. Atkinson, Esq., West View, Eastburv Avenue, Northwood, Middlesex. (Price 5s. 6d. for set of two Mouth-Measurers, with accessories.) 10 Mr. Daniel Jones [Feb. 9, be pushed along (by means of the handle D) and made to project to different lengths from the end of the tube. A projecting piece of metal, called a "tooth-stop " (E), is attached to the tul)e ; it can be fixed at various points. FGH is a wire handle. Fig. 3. Atkinson's Mouth-Measurer. ACB tube, D handle of wire, E tooth-top, FGH handle. Fig. 4. Atkinson's Mouth-Measurer in Position. To use the instrument, it is placed in the mouth either in the manner shown in Fig. 4, or else so that the tube is in contact with the teeth at the tooth-stop and also in contact with some point of the palate (the position of the apparatus depending on the nature of the sound to be analysed). The wire is then pushed along until the end of it is felt to touch the tongue. The instrument is withdrawn and applied to a previously-prepared diagram of the shape of the observer's palate. The position of the end of the wire is then marked on the paper. Further observations are then taken with the tooth-stop fixed at other points. In this way the positions of other points of the surface 3917] on Experimental Phonetics 11 of the ton (B) Paetially-aspieated p ; (C) Unaspieated p ; (D) Unvoiced b ; AND (E) Fully- Voiced b — each followed by the vowel a. B A rs. i ai: t c^; 1 1 p^ . ^ ^^ . • h L C^J Ou 71. t ^^ ^^/^-V^.V~^,V/V^ Fig. 14. — Simultaneous Mouth- and Nose-Teacings of (A) Feench plante (Female Voice) ; (B) English plant (Male Voice). Note the absence of ii in French. [This experiment was performed, and the difi'erences in the effects of various speech-sounds were shown. Special attention was called 1917] on Experimental Phonetics 17 to the variations in the size of the vibrations when vowels were pronounced on different pitches of the voice. Xumerous lantern -sUdes illustrating kjmographic tracings were then shown. Some of these tracings are reproduced in Figs. 11 to 15. Such tracings are chiefly useful (1) for detecting the presence or absence of voice ; (2) for detecting the presence or absence of nasality ; (3) for measuring the lengths of sounds ; and (4) for calculating the pitch of the voice.] B M^M^^^^^^^^^^^ Fig. 15. — Simultaneous Mouth- and Nose-Tracings of (A) side ; (B) sign ; (C) nine ; and (D) niwe Peonounced in Cockney-fashion, Note the differences in the nose-tracings. The above examples show to what extent experimental phonetics may be useful to the language learner. It furnishes him with much of the information he wants in regard to pronunciation. The practical linguist should make these ascertained facts the basis of his study of the pronunciation of the language he is learning. He will be able to infer from them how he must proceed in order to get his own organs of speech to perform the movements required by the foreign language. In conclusion, it may be as well to point out that as these scientific methods of analysis are useful to the linguist, so also the Vol. XXII. (No. Ill) c 18 Mr. Daniel Jones on Experimental Phonetics [Feb. 9, accomplishments of the Hngui«t are sometimes found to have their uses to the man of science. Thus it is possible by means of a speech process to demonstrate in a remarkable way the existence of harmonics in a musical note, to show, for instance, that if the note c is sung, there is sounding- simultaneously the well-known series of harmonics c', g\ c'\ e', g'\ etc. This fact is made evident by putting the mouth into a series of positions which will act as resonators and reinforce different harmonics one after the other. If only one position is taken up by the mouth, some harmonic or other . is necessarily reinforced, but it is extremely diflBcult to detect which. But by making rapid changes from one mouth-position to another, the successive har- monics become clearly audible hy contrast. The speech-movement which makes these harmonics come out most clearly is to start by holding the tongue in the position of the English sound of ng and rounding the lips and gradually separating them. At close quarters the effect is that of an arpeggio played on a tiny harp. If the voice-note is changed, the same arpeggio is heard in a different key. [This experiment was performed.] This phonetic experiment may or may not prove to have some direct value in the direction of elucidating problems of sound-quality, but at any rate it is useful as a practical demonstration Of the presence of harmonics in a musical sound. [D.J.] 1917] Authors' Dedications in the Seventeenth Century 19 WEEKLY EVENING MEETING, Friday, February 16, 1917. The Right Hon. Lord Wrexbury, P.O., Vice-President, in the Chair. Very Rev. H. Hensley Hexsox, Dean of Durham. Authors' Dedications in the Seventeenth Century. Dedications now mostly nothing more than personal compliments, but once had a greater importance. In some cases they possess considerable value, both historical and biographical. In seventeenth century the " dedicatory epistle " often a concise statement of author's argument, reasons for writing, and circumstances. Hardly excessive to say that the introductory compositions are the only portions of some famous books now known generally. Literary finish secured by the desire to make a favourable impression. Reasons why authors sought the patronage of prominent persons. Fuller's view and practice. Financial policy latent in dedications explains much of the adulation which impairs their credit and literary quality. Dedications dictated by personal friendship have no taint of flattery or self-seeking. Extraordinary dedications are the satirical (e.g., George Withers and Lord Herbert), and polemical (e.g., Milton, Heylyn, Hall). Herbert and Bunyan are examples of edifying dedications, and stand by themselves Selden's dedication of " Titles of Honour " to Mr. Edward Hey ward gives his opinion of conven- tional dedications. The " Dedicatory Letter " prefixed to the republication of this treatise is almost an essay on dedication. Selden, like Fuller, divides authors' dedications into three classes — instruction, censure, love and honour. We may accept a three-fold classification — personal, official, financial. Selden was exceptional as a man of comparative wealth, but he had experience in connexion with his '' History of Tithes " of the risks of independence. His servile description of James I. may stand beside Johnson's interview with George. III. Choice of person to whom a book should be dedicated was determined by a variety of considerations — personal inclination, obvious fitness, official propriety, polemical effect, calculations of prudence, financial interest. A dedication implied patronage, which was indispensable in that age, when few authors made money by their works. Hall " wrote books to buy books " ; Fuller boasted that " no stationer had lost by him." Both were exceptionally successful writers. Mostly the author depended on the patron's complimentary c 2 20 'Authors' Dedications in Seventeenth Century [Feb. 16, present. Hall provides examples of many varieties of dedication. He links together theology and literature. " The children of the bondman are the goods of the parent's master " is his principle in dedicating " Heaven upon Earth " to his father's employer, the Earl of Huntingdon. As a royal cliaplain, he naturally dedicated many works to Prince Henry and James I. These dedications illustrate the incidental historical value of such compositions. Fuller's numerous dedications are filled with side-lights on men and events. An excellent example is his dedication of the Fifth Book of his *' Church History " to Cranfield, Earl of Middlesex. In varying measure the same kind of value attaches to all Fuller's numerous dedications. The extent of his acquaintance is indicated by the number and variety of his patrons, which Mr. Brewer holds to be also the disproof of the imputation of "intentional dishonesty, designed to curry favour with the reigning powers," which was brought against him in his lifetime and since. His fondness for infant-patrons, and defence of it. Fuller's dedicatory epistles are fullest of personal interest ; Jeremy Taylor's have the highest literary quality. These were sometimes in length and form rather essays than epistles, e.g., the dedication of " The Liberty of Prophesying." He regards the epistle dedicatory as far more than a merely compli- mentary composition ; and treats it rather as a modern writer would treat his preface or introduction. His dedication of the first edition of " The Great Exemplar " to the second Lady Carbery is a curious example of tactfulness. In the dedication of " A Collection of Polemical and Moral Discourses" to Lord Hatton in 1657, Taylor discusses patrons and books. Charles II., an edifying figure in dedicatory epistles. His romantic history and the re-establishment of the national hierarchy as a consequence of his restoration may explain this. Eobert Barclay's dedication of the " Apology," 1675, a notable exception to the general tone of Caroline dedications. Possibly the " Apology " may have reached the King through the Duke of York, with whom Barclay was acquainted. Heylyn and Burnet tried to connect the Restoration with their polemical ol)ject in writing. A selection of " dedicatory epistles " of the seventeenth century, edited by a competent historian, would be both serviceable to students and interesting to the general reader. [H. H. H.] WEEKLY EVENING MEETING, Friday, February 28, 1917. [No Discourse Delivered.] 1917] Cellulose and Chemical Industry (1866-1916) 21 WEEKLY EVENIXG MEETING, Friday, March 2, 1917. Sir William Phipsox Beale, Bart., K.C. M.P., Vice-President, iu the Chair. Charles F. Cross, B.Sc. F.C.S. Y.P.I.C. Cellulose and Chemical Industry (1866-1916). Cellulose in the natural order ranks with the air-gases, and water as a primary substance, or, in the sense of the Creek cosmology, an " element." In the affairs of " the world," that is, man's world, it plays a similar predominant part by reason of its original qualities of struc- ture and of resistance as a chemical individual to oxygen and water. Under chemical treatment there results a development of structural adaptabihty through the plastic properties of characteristic synthetic derivatives ; and in the special properties of the ceUulose nitrates there is realized the many-sided technical ideal of explosive and the indispensable condition qua matter of modern warfare. The chemical industrial developments of cellulose are character- istic of the modern age, which in this section of technology dates from 1866. At this date the necessity of meeting the progressive consumption of paper by a supply of original raw cellulose material led to the introduction of esparto grass by Thos. Routledge, and to the investigation of wood material as the most massive form and source of cellulose. As the result of the pioneer work of an Anglo- Swedish group, of which the late C. D. Ekman was a prominent member, and for which his English collaborators (Messrs. Thomson, Bonar and Co., and George Fry, F.L.S., of Berwick-on-Tweed) supplied the means, the business organization, and a considerable contribution to the technical scientific basis of investigation, the wood pulp (cellulose) industry was launched. It was considerably developed by the technical improvements introduced by our countryman, Edward Partington, now Lord Doverdale, who also brought to bear on the industry organizing and business capabilities of a high order ; the results, which have been cumulatively successful, are known to the world. In these processes of resolving raw material into paper-maker's " pulps," the ceUulose, as the chemically inert or non-reactive basis of the raw materials, resists the severe treatments required to attack the 22 Mr. Charles F. Cross [March 2, non-cellulose components. The esparto compound celluloses are resolved by alkaline treatment (caustic soda solution at 120°-130°), the wood substance (ligno-cellulose) by treatment with acid com- pounds (bi-sulphites) in solution at 140°-160^ The soluble by-products, derivatives of the non-cellulose complex, amounting in either case to 50 per tsent. of the original raw material, are in effect waste products. In the case of the esparto they are burned incidentally to the recovery of the soda ; but the " wood liquor " by-product is still in the main a waste, and a colossal one. The " positive " chemical technology of cellulose is necessarily based upon its reactivity, and the industries w^hich exploit the reaction changes of cellulose are of widely divergent character ; those of Group A are based upon reactions of decomposition ; those of Group B are based upon the properties of synthetical derivatives. Of Group A, the resolution of cellulose into sugar (dextrose) by acid hydrolysis is the basis (1) of a process for the preparation of industrial (ethyl) alcohol from wood, and more economically from wood w^astes. According to our latest information the technical difficulties presented by this apparently simple process have been so far overcome that the alcohol is produced on the large scale at a cost of 2^d. per gallon, exclusive of the small cost of the w^aste wood material. Under these most favourable conditions, however, the yield of alcohol is only 5 per cent, of the weight of the wood sub- stance, or say 8 per cent, of its cellulose content, leaving therefore a very large item of final Avaste to the debit account of the chemist.* (2) Saw^dust, or other wood waste, fused — i.e. heated at high temperatures — with the caustic alkalis is destructively oxidized, and the main product of the oxidation is oxalic acid ; this process is in effect the main source of the acid, as an industrial product. (3) Waste w^ood subjected to destructive distillation in closed retorts is resolved into gaseous and volatile liquid products, with a solid residue of charcoal or pseudo-carbon. The liquid products con- tain acetic acid, acetone, and methyl-alcohol as main constituents, and have been the main source of supply of these chemical individuals, which, as reagents especially, are indispensable in modern chemical industry. In this direction, however, cellulose material and its wasteful treatment by destructive distillation are being supplanted by a direct and controlled synthesis from calcium carbide, acetylene being quanti- tatively transformed into acetaldehyde, and this into acetic acid. In this new industry the pioneers in this country are the British Cellulose and Chemical Manufacturing Company, Spondon, Derby. (4) Cellulose heated in full contact with oxygen is burned with the familiar flame combustion ; but from all the natural structural forms there is a residue of inorganic matter (ash) which when present * See Journ. Soc. Chem. Ind., X300-1916. 1917] on Cellulose and Chemical Industry (1866-1916) 28 in important proportion preserves the general structural details of the original. This intimate combination of cellulose with inorganic matter is a characteristic property of colloids of which cellulose is the prototype. It is the basis of innumerable processes incidental to the dyeing and colouring of cellulose fabrics and tissues. But the production of a combustion skeleton for utilization as an industrial product is a modern and noteworthy realization of a primary cellulose quality " strong even in death." The familiar incandescence gas mantle is the skeleton of a textile material impregnated as such, or as we may say, " in the flesh," with colloidal thorium and cerium oxides, and afterwards cremated. Of the cellulose industries of Group B, those (1) based on the nitric esters are of preponderating importance, for they include the production of the modern military explosives, and they connote developments in pure and applied science peculiarly characteristic of the age. Cellulose nitrate not only fulfils the ideal of chemical effect, i.e. total conversion of solid into gaseous matter, at maximum increase of volume (or pressure) further increased by the temperature of com- bustion, but is a stable form of this high chemical potential, and further owing to its colloidal plastic properties can be moulded into any desired form, and is therefore able to meet the most exacting specification of ballistic requirements. There is no doubt that mankind is directly indebted for its " smokeless " powders and the basis of the vast developments of modern military power to the pioneer work of Alfred Nobel and his collaborators. The lower degrees of " nitration " of cellulose are represented by products which are the basis of "celluloid," and the celluloid industries connote the production of a large number of familiar objects both useful and ornamental, and a progressively increased production from the date of the pioneer work of the American inventor, Hyatt (1869).* Celluloid realizes a very high order of plasticity, and it is this structural potentiality which enables it to maintain its industrial leadership in spite of its disadvantages of high inflammability, frequently and tragically manifested, (2) The analogues of the nitric esters are the acetic esters of cellulose, derivatives which are necessarily colloids with plastic capa- bilities, water-resistant as are the nitrates, and with a higher order of resistance to heat (unchanged at 200' C), and the ordinary inflam- mability of organic substances. Important uses of the cellulose acetates already established are : {ct) in aeroplane construction, for treating to render taut and impermeable the textile fabric which constitutes the air-resistant surface of the wings ; {h) in the form of film, as the " emulsion-film " support in photographic work, notably for the preparation of the continuous cinema picture ; (c) for a See Journ. Soc. Chem. Ind., xxxiii. (1914), p. 225. •24 - Mr. Charles F. Cross [March 2, varnish for metallic surfaces, and notably for electrical insulation and applications whicli depend upon exceptionally low inductive capacity. In the above brief account of the cellulose nitrates and acetates there is the implicit suggestion of the production of artificial textile threads by drawing the solutions of these bodies through orifices of suitable form and dimensions, such that after removal of the solvent liquid tlie re-solidified and structureless ester constitutes a cylinder of hyaline material of uniform diameter. The industrial production of artificial threads, and notably of the " silk " or lustra cellulose, we owe to the pioneer enterprise and purposeful tenacity of a French technologist, H. de Chardonnet. But cellulose nitrate as matiere premiere has many and obvious defects ; hence the alternative plastic forms or derivatives of cellulose have progressively displaced the original industrial product, which had a brilliant career of success in the early years of this century. There are three main rival processes of which the underlying ])rinciples are common. They are expressed in the stages or phases of the process : — (1) Cellulose is transformed by reaction into a synthetic deriva- tive— dissolved as such to an 8 per cent, solution (calculated as cellulose), filtered and continuously projected, or drawn through fine tubes or orifices, into a solidifying or setting medium. (2) The thread us a unit filament (monofil, crin, crinole), or multiple group of twisted filaments (artificial silk), is a cellulose ester or other derivative, and is chemically treated to remove combined groups, or impurities as by-products of decomposing reactions ; the thread substance is cellulose, reappearing as such after the cycle of changes. The three cellulose derivatives on which these important industrial processes are based are : (1) The nitric esters ; drawn or " spun," as ether-alcohol solution (Chardonnet process). (2) The ammonia-soluble cellulose-hydrate-copper-hydroxide com- pounds (Cuprammonium process). (3) The xanthic or sulpho-carbonic ester, synthesized in two stages : {a) mercerization of the cellulose ; {b) combination of the alkali cellulose with carbon disulphide, and solution of the product in water (Viscose process). Of these the Viscose process is now predominant by reason of its advantages, technical and economic. It will be noted that the material " elements " of the industry are cellulose, common salt, carbon and Buli)hur, than which no simpler terms could be devised, even as an a priori proposition. Of other industrial a])plications of the Viscose process, the pro- duction of transparent film in continuous length is a variation only of the process al)ove descriljed, the licpiid Viscose being drawn througii a controlled adjustal)le slit of 1-5 m. width, into a setting solution 1917] on Cellulose and Chemical Industry (1866-1916) 25 or precipitant, which converts it at once into the sohd state, but retaining- 80 per cent, of water. This hydrated product is purified by successive treatments, and is finally dehydrated and dried with a shrinkage of 33 per cent., the 1 • 5 m. of hydrated xanthate, as first precipitated, being reduced to a width of 1 m. in the finished cellulose film. This is a noteworthy achievement in chemical engineering, and is entirely due to the inventive persistence of the personnel of the Societe Frangaise de la Viscose, especially to MM. L. Naudin and J. E. Brandenberger. It is a pleasant duty to recognize technical pioneer work of so high an order. In addition to these main applications there are many other uses of the reactions involved in the Viscose cycle. Thus " merceriza- tion " of cellulose is an application of the interaction of cellulose (textiles) and caustic soda, to produce lustre effects and finishes upon cotton goods. The structural changes of yarns and cloths determined by these reactions were investigated by John Mercer at a period which long antedates our half century of progress. To Mercer's " genial " anticipations there succeeded a long incubation period. A few discoveries of minor import in this field then revived interest in the major product, the alkali cellulose of the A'iscose cycle, and " mercerized goods " became a textile market of first note and importance. The lecture was illustrated by incidental experimental demonstra- tions, including the drawing of " artificial " cellulose threads from the cuprammonium solution ; also by a selection of specimens repre- sentative of the industries specially described. It is proper to mention by name the manufacturing firms who freely supplied these, as they are firms and corpoiations not merely industrially successful, but pioneers who have developed the technical science of these industries as their essential basis, and the list of names is a technological record. Cortaulds, Ltd., Coventry. (S. S. Napper, Chief Chemist.) Artificial silks, monofil and film tissues. Experimental demon- stration of artificial thread formation. Societe Fran9aise de la Viscose, Paris. (MM. J. E. Brandenberger and E. Defaucamberge.) " Cellophane " film fabrics. Viscoid solid products. Messrs. Olive and Partington, Glossop. Specimens illustrating bi-sulphite wood-pulp process. Messrs. Tullis, Russell and Co., Markinich, N.B. Specimens of esparto pulp, papers and by-products. Messrs. Burgess, Ledward and Co., Manchester. (\Y. H. Pennington.) Mercerized yarns, illustrating the technical effects of merceriza- tion. Special fast dyeings of artificial silks. 26 Cellulose and Chemical Industry [March 2, British Cellulose and Chemical Manufacturiog Co., London and Derby. (Drs. C. and H. Dreyfus.) Cellulose acetate films, varnish and solids. Aeroplane fabrics. Messrs. J. R. Denison and Co., Bradford. (J. R. Denison.) Specimens of mercerized cotton fabrics. Special finishes. The Plaissetty Mantle Co., London. (T. Terrell, K.C.) Specimens of incandescence gas mantles and stages of special processes. The Viscose Development Co., Ltd., Bromley, Kent. (0. Mason, Manager.) Specimens of cap films, illustrating processes of fixing pressure proof caps to bottles, etc. To Mr. W. MacNab, F.I.C., I was indebted for a collection of Military Service Explosives ; and the Director of the Royal Gardens, Kew, through Mr. J. M. Hillier, Keeper of Museums, kindly supplied specimen skeleton leaves. I was indebted to Dr. J. N. Goldsmith for specimens of celluloid ; and to Mr. J. Lawrence, of Messrs. Blair Campbell and Co. (Glasgow), for the preparation of cylinders of wood charcoal demonstrating the volume changes of hard woods in the process of destructive distil- lation. [C.F.C.] 1917] General Monthly Meeting 27 GENERAL MONTHLY MEETING, Monday, March 5, 1917. Sir James Crichton-Browne, J.P. M.D. LL.D. D.Sc. F.R.S., Treasurer and Vice-President, in the Chair. M. Sevmore Branfoot, Mrs. G. Gascoigne, Mrs. Algernon Mansel, Mrs. Reginald F. Yorke, were elected Members. The Chairman read the following letter, which had been received from the Honorary Member elected at the General Meeting on December 4, 1916 : — Via in Lucina, 17, Roma. February 2, 1917. Your Geace and Much Honoured President, I have received the Diploma signed by you, notifying my election as an Honorary Member of the Royal Institution of Great Britain. I am exceedingly grateful at the honour conferred on me, and beg you to ofier my best thanks to my new colleagues who unanimously elected me. I appreciated in its full extent this mark of distinction. Believe me, honoured Sir, Yours very faithfully, (Signed) VITO VOLTERRA. To His Grace the Duke of Northumberland, K.G. P.C. F.R.S., President of the Royal Institution of Great Britain, London. The Presents received since the last Meeting were laid on the table, and the thanks of the Members returned for the same, viz. : — FROM Accademia dei Lincei, Eeale, Boma — Rendiconti, Classe di Scienze Fisiche, Mathematiche e Naturali. Serie Quinta, Vol. XXVI., 1° Semestre, Fasc. 1. 8vo. 1917. American Chemical Society — Journal for Feb. 1917. 8vo. Journal of Industrial and Engineering Chemistry for Feb. 1917. 8vo. American Geographical Society — Geographical Review for Jan. 1917. Svo. American Journal of Physiology — Vol. XLII. No. 3. Svo. 1917. 28 General Monthly Meeting [March 5, Astronomical Society, Boyal — Monthly Notices, Vol. LXXVII. No. 2, Dec. 1916. 8vo British Architects, Boyal Institute o/— Journal, Third Series, Vol. XXIV. No. 6. 4to. 1916. British Astronomical Association —Journal, Vol. XXVII. No. 3. 8vo. 1917. Buchanan, John Y., M.A. F.R.S. M.B.I. {the Author)— Gom^tes Rendus of Observation and Reasoning. 8vo. 1917. Buenos Aires — Monthly Bulletin of Municipal Statistics for Sept.-Oct. 1916. 4to. Channel Tunnel Company — The Channel Tunnel : Military Aspect of the Question. By Lord Sydenham. The Channel Tunnel and the World War. 12mo. 1917. Chemical Industry, Society o/— Journal, Vol. XXXVI. Nos. 2-3. Svo. 1917. Cornioall Royal Polytechnic /Socie^?/— Eighty-Third Annual Report, New Series, Vol. III. Part 2. Svo. 1916. Editors — Athenffium for Feb. 1917. 4to. Author for Feb. 1917. Svo. Chemical News for Feb. 1917. 4to. Chemist and Druggist for Feb. 1917. Svo. Church Gazette for Feb. 1917. Svo. Concrete for Feb. 1917. Svo. Dyer and Calico Printer for Feb. 1917. 4to. Electrical Engineering for Feb. 1917. 4to. Electrical Industries for Feb. 1917. 4to. Electrical Review for Feb. 1917. 4to. Electrical Times for Feb. 1917. 4to. Electricity for Feb. 1917. Svo. Engineer for Feb. 1917. fol. Engineering for Feb. 1917. fol. Ferro-Concrete for Feb. 1917. Svo. General Electric Review for Feb. 1917. Svo. Horological Journal for Feb. 1917. Svo. Illuminating Engineer for Feb. 1917. Svo. Journal of Physical Chemistry for Jan. 1917. Svo. Journal of the British Dental Association for Feb. 1917. Svo. Junior Mechanics for Feb. 1917. Svo. Law Journal for Feb. 1917. Svo. Marine Magazine for Feb. 1917. 4to. Model Engineer for Feb. 1917. Svo. :Musical Times for Feb. 1917. Svo. Nature for Feb. 1917. 4to. New Church ]\Iagazine for Feb. 1917. Svo. Nuovo Cimento for May-June, 1916. Svo. Page's Weekly for Feb. 1917. Svo. Physical Review for Jan. 1917. Svo. Power for Feb. 1917. Svo. Power-User for Feb. 1917. Svo. Science Abstracts for Jan. 1917. Svo. Tcheque, La Nation, for Jan. 1917. Svo. War and Peace for Feb. 1917. Svo. Wireless World for Feb. 1917. Svo. Zoophilist for Feb. 1917. Svo. Electrical Engineers, Institution o/— Journal, Vol. LV. No. 263. Svo. 1917. Florence, Biblioteca Nazionale Cm^raZc— Bollettino for Feb. 1917. Svo. Geological Society o/I;ondo?i— Abstracts of Proceedings, No. 1001. Svo. 1917. Holmes Forbes, A. W., M.A. {the Author)— Salvsition by Science. Svo. 1917. Meteorological Observations and Essays. By John Dalton. Svo. 1793. 1917] General Monthly Meeting 29 Indian Association for Cultivation of Science — Vol. I. 8vo. 1917. Jugoslav Committee — The Jugoslavs in Future Europe. By H. Hinkovic. 12mo. 1917. Linnean Society— Journal : Botany, Vol. XLIII. No. 293. 8vo. 1916. London County Council — Gazette for Feb. 1917. 4to. London Society — Journal for Feb. 1917. 8vo. Meteorological Ojffice— Weekly Weather Keports for Feb. 1917. 4to. Daily Readings for Nov. 1916, 4to. Geophysical Journal for March and April, 1915. Meteorological Society, Boy al— J ournaA, Vol. XLIII. Jan. 1917. Svo. New York, Society for Experimental Biology —Proceedings, Vol. XIV. No. 3. Svo. 1916. New Zealand, High Comynissioner for — Patent Office Journal, Feb. 1917. Svo. Pharmaceutical Society of Great Britain — Journal for Feb, 1917. Svo. Photographic Society, Boi/aZ— Journal, Vol. LVII. No. 2. Svo. 1917. Physical Society o/ LorK^oji— Proceedings, Vol. XXIX. Part 2. Svo. 1917. Popovic, Professor P. — The Literature of the Southern Slavs. Svo. 1917. Rome, Ministry of Public Works — Giornale del Genio Civile for Oct -Nov. 1916. Svo. Royal College of Physicians — List of Fellov^s, etc. Svo. 1917. Royal Colonial Instittite—V nited Empire, Vol. VIII. No. 2. Svo. 1917. Royal Engineers' Ins titiite— Journal, Vol. XXV. No. 3. Svo. 1917. Royal Society of Arts — Journal for Feb. 1917. Svo. Salford, County Borough o/— Sixty-Eighth Report of the Museums, Libraries and Parks Committee, 1915- 16. Svo. 1917. Selhorne Society — Selborne Magazine for Feb. 1917. Svo. Societd degli Spettroscopisti Italiani — Memorie, Series 2, Vol. VI. Disp. 1. 4to. 1917. Statistical Society, Royal— J oxxxnaX, Vol. LXXX. Part 1, Jan. 1917. Svo. Steeves, Mrs. G. Walter— A Book of Verses. By G. Walter Steeves, M.D. 12mo. 1917. Tdhoku Imperial University — Mathematical Journal, Vol. X. No. 4. Svo. 1916. United Service Institution, Royal — Journal for Jan. 1917. Svo. United States, Department of Agriculture — Journal of Agricultural Research, Vol. VIII. Nos. 4-6. 1917. Svo. Experiment Station Record, Vol. XXXV. No. 9. Svo. 1916. United States, Department of Commerce and Labour — Bulletin of the Bureau of Standards, Vol. XIIL No. 3. Svo. 1916. Technologic Papers, Nos. 6, 61, 62, SO. Svo. 1916. Washington, National Academy of Sciences — Proceedings. Vol. III. No. 1. 1917. Yorkshire Archaeological Society — Journal, Vol. XXIV. Part 94. Svo. 1916, Annual Report for Year 1916. Svo. 30 Colonel Sir Almroth E. Wright [March 9, WEEKLY EVENING MEETING, Friday, March 9, 1917, Sir Jaaies Crichton-Browne, J.P. M.D. LL.D. F.R.S., Treasurer and Vice-President, in the Chair. CoLOXEL Sir Almroth E. Wright, M.D. C.B. F.R.S. M.R.L, A Consultant Physician to the British Army in France. The Treatment of War Wounds.* We are wont to classify the patients in our military hospitals into sick and wounded. In reality all, or nearly all, are suffering from bacterial infections. And in this lies the essential difference between the sick and the wounded, that the sick are suffering from infections spontaneously contracted, the wounded from infections induced by mechanical injuries. My theme is the treatment of this latter class of infections. They are distinguished by certain quite special features. In spontaneous infection we have to deal with microbes which have fought their way into the body, and generally only a single species of microbe will have done this. We have in wounds microbes mechani- cally driven in, and every sort of microbe which exists in external nature may thus be introduced. Furthermore, the disposition of the microbes in war wounds is fundamentally different from that in ordinary surgical wounds. In war wounds the infection is disposed in part upon lacerated raw surfaces ; and in part it is carried deep into the substance of the tissues. Moreover, the infected lacerated surfaces are left denuded of skin and exposed to injurious external influences ; and the infec- tion which is carried down into the tissues is left as a buried infection. Now there is in ordinary surgical operations nothing at all comparable to this. The surgeon would never leave cut surfaces naked and exposed, or a buried focus of infection unopened. This will have brought it home to you how especially difficult are the conditions which have to be dealt with in the infected war wound. But let me, before embarking upon the question of their treatment, first tell you something about the natural agencies by which the inroads of microbes are combated. You are, of course, aware that we are guarded against microbic infection by our blood fluids and our white blood corpuscles. * [Supplemented by Additional Matter relating to Antiseptics and the Method of Carrel, lleprinted from Lancet, June 23, 1917.] 1917] on The Treatment of War Wounds 31 The Body Fluids. Let me begin with the blood fluids, and let me take you directly to the following experiment. I call it the experiment of pijo-sero- cuUure — i.e. the experiment in which we implant pus into serum to see which of the microbes of the wound can grow in the blood fluids. We procure for our experiment a suppurating wound. We take Fig. 1.— Method of pyo-sero-culture.—A, Pipette which has been implanted by the wet-wall method, and has then been filled in by the wash and after-wash procedure with unit-volumes of serum. By the side of the pipette to the right is ranged a series of drops representing the series of unit-volumes of serum blown out in order from the pipette, and, finally, to the right of the drops is a series of lines representing linear implantations made upon agar. B, Eesults of the series of linear implantations made with the unit- volumes of the patient's serum. C, Results of the series of linear implantations made with the unit-volumes of the normal serum which was used as a control. from it a specimen of pus containing a large variety of different organisms. At the same time we take from the patient's finger a sample of blood, and we take a specimen also of our own. When the serum has issued from the clot we take a capillary pipette, fit a rubber teat to the barrel, and inscribe a mark upon the stem at 32 Colonel Sir Almroth E. Wright [March 9, about say one-third of an inch from the tip. We now aspirate a little pus into the stem, drawing it up only as far as our fiducial mark, and blowing it out again leave a wash of pus upon the walls. This done, we sterilize the tip of the pipette, and then aspirate into the stem a series of unit- volumes of serum, dividing each volume off from the next by a bubble of air. The pipette when filled in this manner presents the ap- pearance shown in Fig. 1 ; and we have in the proximal end our first and heaviest implantation of pus, and in the distal end our last and hghtest implantation. The pipette is now placed in the incubator to allow every microbe which is capable of growino^ in serum to do so. After an in- terval of six or more hours we proceed to our examination. What we do is to blow out our series of unit-volumes of serum in separate drops and examine under the micro- scope ; or, better, wx plant out a sample of each drop upon a separate seed-bed. Here in B and C you have the results of such culture represented diagrammatically — the meagre crop in B being that obtained with the patient's serum, and the more copious crop in C being that obtained with normal serum. And you have in the next figure (Fig. 2) a drawing of an agar tube implanted from a pyo-sero-culture made with the serum of a wounded man. In the upper part of the agar tube you have two seed-plots implanted from the distal portion of the capillary stem. These have remained sterile. In the middle of the tube you see four plots implanted from the unit-volumes of serum which occupied the middle region of the capillary stem. These have grown colonies of only one species of microbe — the streptococcus. At the bottom of the tube you see seed-plots implanted from tlie proximal end of the capillary stem. These are overgrown with colonies of staphylococcus. But no doubt interspersed with and overgrown by these are also colonies of strepto- cocci. If, instead of cultures from the patient's serum, I had been showing you here cultures from normal serum, what you would have seen would have been a much larger number of fertile seed-plots, and ^ Fig. 2. — A portion of a pyo-sero-culture planted out upon an agar slant divided up by furrows into a series of seed- beds. 1917] on The Treatment of War Wounds 33 tlie seed-plots implanted from the proximal end of the pipette would have shown a larg^e assortment of different colonies. AVe learn from such experiments three lessons : first, that in the uncorrupted serum in the distal region of the pipette only two species of microbes from the wound can grow and multiply ; secondly, that irf the corrupted serum in the proximal end of the pipette all the microbes of the wound can grow ; and, thirdly, we learn from a com- parison of the wounded man's serum with the normal serum that the former offers more resistance to microbic growth, and is less easily corrupted l)y the addition of pus. GauM of the Corruption of the Serum. Experiments of this kind clearly do not tell us the cause of the cor- ruption of the serum. That corruption may be due to some chemical substance contributed by the pus to the serum, or to something special in the character of the bacteria implanted. This point we can clear op as follows. We go back to our yery septic wound. We clean it out carefully by syringing. That leayes us with a wound cavity clean but still abundantly infected. AVe then take the little cupping apparatus which is shown in Fig. 3. We apply it to the walls of tlie Fig. 3.— Lymph leech in position, showing technique for exhaus- ting the air. wound, using light pressure. Then, puncturing the attached rubber tube with the needle of a hypodermic syringe, we withdraw the contained air, and leave our lymph leech in situ adhering by negative pressure till the time for re-dressing the wound comes round. When we now go back to our wound we find there two quite different discharges. AVe have in the general cavity of the wound a thick pus containing many broken-down leucocytes and pullulating with all sorts of microbes. In the body of the lymph leech we have a nearly clear lymph containing well-preserved leucocytes and only a very few Vol. XXII. (No. ill) ^ d 34 Colonel Sir Almroth E. Wright [March 9, staphylococci and streptococci. Since we had on every part of the walls precisely the same amount and kind of bacterial infection, and since we are in each case dealing with the self-same lymph and leucocytes, this difference of results is imputable, not to our having in the lymph leech a different bacterial implantation, but to the negative pressure having furnished a larger proportion of blood fluids. But with this the problem is, as you see, only incompletely resolved. We have learned that the corruption of the lymph is not determined by the nature of the bacterial implantation ; we have reason to think it is hindered by a larger afflux of lymph; and it looks as if it might have something to do with the breaking down of the leucocytes. But we have not yet put our finger upon the particular element that takes away from the serum its power of inhibiting microbic growth, and converts it into a congenial pabulum for all manner of micro-organisms. Let me in this connexion invite you to consider, for that may perhaps put us on the path for the solution of our problem, a scheme of classification of the albuminous substances. I w^ould propose to classify them from the point of view of their capacity to furnish pabulum for microbes, and to distinguish three classes of albuminous substances. First, would come digested alhiunens. It is familiar matter that these furnish very congenial pabulum for microbes. In the form of peptone we use them for all our artificial cultures. A second category of albumens would be native albumens. Muscle, milk, and eggs furnish such albumens. These are not like digested albumens, directly assimilable. Before they can be assimilated, wliether by ourselves or by microbes, they must be broken down into simpler elements by digestion. To that end we, and a certain number of microbes also, are furnished with digestive ferments. There is yet a third class of albumens. I would venture to call these defended or protected albumens. These cannot, like the digested albumens, be directly assimilated. Nor can they, like the native albumens, be directly digested. They are specially defended against the attack of digestive ferments. The albumens of the serum fall into this class of " defended albumens." It is well known with respect to serum that it has an antizymotic, and in particular an antitryptic, power — a power of neutralizing digestive ferments, and in particular trypsin.* You will, perhaps, not immediately perceive that the fact that the serum is antitryptic in any way elucidates our problem, l^ut let us take that fact and put it in another way and then consider. Let us, instead of saying that tlie serum has an antitryptic property, suy that it has a power of preventing its * Let mo here incidentally call attention to the fact that the application of horse serum will prevent and very effectually relieve the digestive erosion of the skin which is in enterostomy of the upper part of the small intestine produced by the outflow of pancreatic juice. 1917] on The Treatment of War Wounds 85 constituent albumens beint^: converted into pabulum for microbes^ and immediately, as I think, light is projected upon our problem. For once we envisage the facts in that way we are immediately impelled to inquire whether the serum's power of inhibiting bacterial growth may not be due to its power of neutralizing digestive ferments, and whether the corruption of the lymph in the cavity of the wound may not be due to a collapse of its defence against proteolytic attack. That is a point which is very easily settled by direct experiment. And let me now show you what happens when we add trypsin to a serum which has been implanted with microbes. I have here two tubes of a serum implanted two days ago with a minute quantity of pus containing a variety of different microbes. To the one I added trypsin, the quantity added being less than that required to neutralize its antitryptic power. The other tube of the implanted serum served as a control. After implantation both tubes were placed in the incubator. And you see the difference. The trypsinized serum is- turbid with microbic growth. That is, we have here exactly the same result as that obtained in our pyo-sero-culture in those volumes of serum which were corrupted by a heavy implantation of pus ; and the same result also as was in the lymph leech experiment obtained in the discharges in the wound cavity. Our control serum has, as you see, remained almost perfectly clear. That is exactly the same result as was obtained in our pyo-sero-culture in the distal end of our tube, and again in our lymph leech experiment in the cavity of the lymph leech. And the doctrine that the antitryptic power is the protector, and trypsin the corrupter, of the blood fluids wins further support from the following facts : 1. In every suppurating wound there is, as we shall presently see, a source from which trypsin can be derived. 2. Blood fluids which inhibit microbic growth are strongly anti- tryptic ; and blood fluids which we find teeming wdth microbes are tryptic. 3. Examination of the blood shows that all wounded men have a markedly increased antitryptic power, and heavily wounded men on an average a three- or four-fold increased antitryptic power. You saw in our pyo-sero-culture how by that microbic growth is suppressed. You must not miss the meaning of that. It means that the body when endangered takes steps to protect itself non-specifically against all microbic infections of the blood fluids. The Leucocytes. I now pass on to consider the leucocytes and the part they play in the destruction of microbes. You already know with respect to leucocytes that they can emerge from the blood-vessels, burrowing their way out through small pores in the capillary walls ; that they D 2 36 Colonel Sir Almroth E. Wright [March 9, make their way to every focus of infection ; that they ingest microbes when these have first been prepared by the action of the blood fluids ; and, finally, that they can, if things go favourably, digest and dissolve the ingested microbes. There Avould, by consequence, in connexion with the leucocyte, be three functions to study. First would come emigration, then phagocytosis, and lastly intracellular digestion. Emigration has up to the present been studied only in the interior of the organism. You will realise that means that it has been studied only in a difficult setting and in the presence of all manner of disturbing factors, and you will appreciate that we want now a new and better technique. For we require for the treatment of the infected wound to find out how best to call out the leucocytes ; and how, when occasion requires, to restrain their emigration. I have in connexion with this a technique to describe to you ; but first I want you to appreciate what we can and what we cannot expect from leucocytes in the matter of locomotion. Leucocytes can, we know, make their way out through small openings. They can also travel over any ordinary surface. They can edge their way along faster w^hen lightly compressed between two surfaces. They can crawl along strands, creep through a mesh work, and climb a scaffold- ing. But they are unable to climb a vertical glass wall. And again, they are unable to swim, and so once they get into open fluid they simply go to the bottom. We may liken them to very minute slugs crawling along surfaces and climbing trellises, but brought up short by any considerable barrier of fluid. All these points must be considered when seeking for a technique for the experimental study of emigration, using for that study specimens of blood withdrawn from the body. The containing blood- vessel can up to a point be imitated by a glass tube, and we can, to facilitate observation, use tubes drawn out flat, such as shown in Fig. 4. But the artificial differs from our natural capillary in having impermeable instead of permeable walls. This, of course, makes emigration through the walls impossible. None the less, these tubes supply what we want for the study of the movements of leucocytes. We can institute races along the length. But first certain preparations must be made. The course must be cleared of all obstructions — i.e., the red corpuscles must be got out of the way. Xext the leucocytes must all be brought back behind the scratch line. Further, we must provide a scaffolding for the leucocytes to climb. All this can be arranged. We fill in our flat emigration tuljes with blood and seal them at one end. Then, by centrifuging, we l)ring the blood fluids to the top and the corpuscles to the bottom. The lighter leucocytes will now have arranged them- selves in a layer immediately above the red ; and presently the super- natant fluid will clot and the mesh work of fibrin will then provide the scaffolding we require. We can now impose upon the clot— let me for convenience call it the white clot — any chemical agent we 1917] on The Treatment of War Wounds 37 please and let it slowly diffuse down to the leucocytes. For the study of the effect of bacterial infection, we can introduce microhes into the blood before this is filled into the tube. Or as an alternatiye blood can be filled into tubes whose walls have been wetted with a microbic culture. Finally, we set our experiment going by placing our emigration tubes in the incubator — that is, we supply to our leucocytes the necessary warmth. And we can at any moment take stock of what is occurring in our tubes by examining through the A B C 1.1 D 1 i Fig. 4. — Drawing of four flattened capillary tubes — A, filled in with blocd; B, a similar tube after centrifugalisation showing above the " white " and below the " red clot '' ; G and D, similar tubes after incubation. Leucocyfcic emigration is in each case visible to the naked eye as an opaque white band occupying the lower portion of the white clot. In D, where physiological salt solution had been imposed upon the white clot, the band of emigration is much broader than in C. walls with the naked eye or with the low power of the microscope. Also by a very simple technique we can extract the clot from the tube and mount and colour it, so as to bring everything clearly into view under the high powers of the microscope. Emigration of Leucocytes : Facts with Practical Application, I must limit myself to showing you in connexion with emigration a few outstanding facts which have a practical application to the treatment of wounds. Let me begin with the naked-eye appearances. We have in Fig. i, C and D, emigration tubes containing centrifuged blood which have been in the incubator for about eight hours. In C — the control tube — we have centrifuged 1)lood to which no addition has been made. In D some weak salt solution has been imposed upon 38 Colonel Sir Almroth E. Wright [March 9, the white clot. The emigrating leucocytes are visible to the eye in the form of a slightly opaque white band extending upwards from the red into the white clot. You see that in D the corpuscles have climbed higher than in C. Fig. 5 shows what such a band of emigrating leucocytes looks Fig. 5. — Magnified view of the band of leucocytic emigration seen in Fig. 4, d. 1917] on The Treatment of War Wounds 39 like under the microscope. Instead of the leucocytes being* all, as you will see in the next figure, congregated together behind the starting line, they here are actively emigrating — the more active out- distancing the others in the race. Fig. 6 shows what happens Avhen 5 per cent, salt solution is im- posed upon the blood. That salt passes down by diffusion and arrests emigration, and I want you to notice on the right of the figure (and more clearly in the inset) that the few white corj^uscles which were beginning to emigrate when the salt solution overtook them are broken up and destroyed. By that trypsin will be set free. Fig. 6. — Magnified view of the leucocytic layer in the case where strong salt solution was superposed upon the white clot. I next show you what happens when microbes have been implanted into the blood. Those microbes — supposing always that they are the sort that can proliferate in blood — grow out into colonies. In Fig. 7 is shown what happens when an excessive implantation has been made, and the bacterial colonies come up very thickly in the blood. You see here that emigration is entirely arrested. If that were to happen in infected tissues it would mean that the organism was there giving up the combat against the microbes. In Fig. 8 we have again streptococcus implanted into the blood, but this time it is a much more sparing implantation. And here, as you see, the leucocytes are carrying out a raid against the microbes, each leucocyte ingesting and filling itself full with microbes. ~\» -J ^ %^ .% ^ V % '>^ Fig. 7. — Leucocytic emigration restrained by excess of streptococcic infection. Fig. 8. — Leucocytes emigrating and attacking a colony of streptococci. March 9, 1917] The Treatment of War Wounds 41 In Fig. 9 I show you what happens when we make into the blood a very heavy implantation of the gangrene l)acillns. Here in the neighbourhood of the leucocytic layer things are for the moment going well for the leucocytes, for they are actively phagocyting. But farther away from that layer there are very numerous colonies of the gangrene bacillus, which are growing unimpeded. The omens are consequently unfavourable. You can see in your mind's eye what is going to happen. In the first place, all further emigration of leucocytes is going to ])c arrested. And, in the second place, the Fig. 9. -Leucocytes emigrating and attacking colonies of the gas gangrene bacillus. leucocytes which have already emigrated and ingested microbes will, instead of successfully digesting them, be gradually poisoned by bacterial toxins. And when the leucocytes are killed, their digestive ferment — trypsin — passes out into the serum. By that, the serum will, as we have seen, be converted into a medium in which microbes can grow and pullulate. Distinction between "Live" and "Dead" Spaces. But we must now come back from these general questions to that of the treatment of the wound. Let me begin by explaining to you — for important questions of treatment hinge apon this — the dis- tinction between " Jive s^paces " and " dead spaces'' ■12 Oolfific;! Sir Alinrolh t. Wri^fil [Miurlj [), III I, lie |;iriiii;i' (>[' viiKriilnriscd Ukkuch W(; liuvt; liv/i .H//fi,rf',.s. In Ui(iH(t w<^ liii,V(; «»|(l,iiiiiiiiir()ii(|il,i<>iiH lor jcKiHl-uiicc to hiw.Loi'iiil \nU:(',l'\()]\. Wy coiitiiiuouHly renewed (ixiidiiiioii (;orni|tlivc rluiii^^cH will l»i-. ronlJiinjiliy lUilyji^oiiiKcd and niiMJc i^ood. Afjiiin, in live KpuccH we li;i.v<; l,crr:iin (Ji;ii <;iiii Im; (tUVcUvcly H<*-iir('.li(td Wy h-ucoctyl-cH ; iiiid if I. lie liiic.l-criiil inrcciion hIiouM nol, lie, (;xl,iii|^iiiHli('d hy iJic fi)'Kl. Iciii^ocylJc, ul Lark rcinroiTf- nicnl.H (»r |('ii(M)('yl,('H <;iin Im; Hii|t|)lied from I, he ejipilluricK leedin^^ Llic live H|»iM*(!,s. Ill .'ill iJiese, reK|»er,|,s live iiiid de;i,d hjiji,(;<;H iivc Hli;ir|)ly Ih'iiil Hiiiuvfi lire round in (jhsiich wliieli luive liee-n lii-niHcd iuid v.nl oil' li'oiii iJieir lilood-Hiijiply, in kIoii^^Iim, in hone s(M{iieHl'ra, iuid in the l,(jxl-ure of cjol/h iUid inl-riiHivc, foniij^n hodieH. And W(i Iim-vc- u dead Hpn. H|)iM'cH yon run oUrw iikikI niiil,l,crH by l»jiM<;iii^^ (tJm,l, in Uic^nil.ionulc of liot/foiiicMfiifiotiH) !i, Uw^cv l)l()()(l Hii|t|)ly iJisil iikmmik iiion; lyiripli jirid iiion; \('M(U)(:y{,i'H to Mic fociiH of infcoUoii ; iiiirl u^niiii yoii cAiii ofl,('ii iimikI iiiiiILcih l>y iiii|)roviri^' (Jk; ()iinJil/y of Uwi lyrri|»li t/liut Ih iJk; r;il,ioii;iJ(; of V}i.<;(;iii(; Uicnipy ; or, ii^'iiiii, you tiiiiy apply l»ot>li iJkjhc. pi-oc(;(liii('H »;oiiciin'(;rilJy. I>ul- vvlicri you n,r(; dciiJiu*,' vvifli nti \i\\'('ci(M\ «lj(!ct to dii.iii;t^''(;. 'I'Ih; tissues ;ire cover<(| in by nuuiy layers of protctctive (tells, the lymph spaces ;i,re sejded o\ — and here the anti- septic stood for four hours in the tube — we have in the barrel a teem- ing multitude of microbes. And in Tube 4, after four hours' contact with the antiseptic, only that very thin layer of the infected lining which coats the barrel lias been sterilised, in the depth of every spike the bacterial colonies have come up quite thickly, and only in immediate contact with the antiseptic have the microbes been killed. I here show you also in a companion tube which has been incubated 24 hours longer that the microbes you have seen growing in the deeper layers very soon penetrate the sterilised superficial layer, and grow out in the culture medium in the barrel of the tube. When we find an antiseptic giving results quite different from those here displayed it will then, for the first time, become a rational programme of operations to use, and leave behind, an antiseptic in a wound with a view to safeguarding the patient during lengthy transport. Suggestion that the bacterial infection in the wound can be kept doivn during transport by frequent re-appJications of an antiseptic. — In the earlier period of the war the only method of re-applying an antiseptic was that of taking down the dressing, syringing the wound, and completely re-dressing. That was, especially in the case of deep wounds and compound fractures, a very lengthy and painful procedure, and one which was nearly impractical )le in transport. For that complete re-dressing there has now been sul)stituted by Carrel a procedure for washing and refreshing the surface of the wound through rubber tubes. According to Carrel, Dakin's antiseptic should be employed, and this should Ije applied every two hours. About the application of this in transport let me say this : that it would, I think, l)e impracticable to carry it out on a sufficiently large scale and sufficiently systematically ; and Dakin's antiseptic applied in an unsystematic manner gives exactly the same results as simply keeping the wound wet. Suggestion that the set-back in the wound during transport could be prevented bg dressing with hypertonic salt solution. — The set-back in the wound with its resulting tragedies could, I think, be avoided by drawing out lymph in a continuous manner from the tissues, and holding up the emigration of leucocytes. Tbe outflow of lympli 11)17] on The Treatment of War Wounds 4:) would drive back and expel invading micTol)es. It would also pre- vent the conditions in the walls of the wound becoming unwholesome to leucocytes. The continuous outpouring of lymph would also effectively combat the corruption of the discharges in the cavity of the wound. And lastly it would prevent any drying up of the wound. The effect of holding up the emigration of leucocytes would be to prevent the corruption of the wound discharges. You will remember that leucocytes, breaking down, furnish the trypsin which corrupts the discharges. We have in a hypertonic solution the therapeutic agent we require for these purposes. The proper way of using it is to apply to the wound three or four layers of lint thoroughly soaked in 5 per cent, salt solution : to impose upon these, as a reinforcement, three or four more layers of lint, thoroughly soaked in saturated salt solution,"' and then cover the whole with jaconet, or other impermeable material. RE3IEDIAL TREAT3IEXT. I now pass from discussion of the method of preventing the set- back that occurs in transport to the discussion of its remedial treat- ment. The set-back will, as we have seen, have given us either a tryptic suppurating wound or a dry slough-covered wound. In each case the first item in treatment will be to get a clean surface. For that it will, in the case of the tryptic suppurating wound, suffice to wash away the tryptic pus. In the case of the desiccated slough-covered wound we must get rid of the sloughs. The rational way to do that will be by cleansing digestion. Such cleansing digestion can be obtained by treating the wound with hypertonic salt solution. This will, as we have already seen, break down leucocytes, setting free trypsin, and then the free trypsin will rapidly, and especially rapidly if hypertonic salt becomes diluted, amputate the dead from the living tissues. Let us note that what we set out to do hx the use of hypertonic salt solution is only to achieve more rapidly, and, as we shall see, with less risk of infection, what putrefaction and the destruction of leucocytes l)y microbes would, if we allowed things to run their course, spontaneously accomplish. The second item of treatment in each case will be to combat the infection which has found a lodgment in the walls of the wound cavity. To deal with this we require an outpouring lymph stream, obtained by hypertonic salt solution. If the train of reasoning I have laid before you is correct, it will follow^ that hypertonic salt solution is the agent we require Ijoth for preventing the set-back due to interruption of treatment in transport, and also for remedial treatment. * The saturated solution diluted with 6 parts of water will give us our 5 per cent. salt. Vol. XXII. (Xo. Ill) e 50 Coionol Sir Almroth E. Wright [March 'J, experniexts which exhibit the properties of Hypertoxic Salt Solutiox. You will very reasonably here expect me to produce experiments to show that a hypertonic salt solution has the virtues I ascribe to it. You will wish to see for yourselves that it attracts water, draws out fluid from moist tissues, sets free trypsin from pus, and initiates digestion. Drawing Action of Strong Salt Solution. I have here {a) agar containing salt to saturation and {h) plain water agar — cast into cylinders in similar 100 c.c. measures, and rendered insoluble by an addition of formalin. Let us consider first the cylinders of water agar. Upon the one of these as it stood in the measure was imposed saturated salt solution, solid salt being afterwards supplied as refjuired. You see that the salt has here drawn out water copiously. The agar has everywhere detached itself from the walls, and we have in the interspace and on the top of the cylinder some 40 to 50 c.c. of fluid. The control cylinder of water agar which has stood in the measure has, as you see, not shrunk at all. Exactly the converse has happened with the cylinders of salt agar. These were extracted from the cylinder measures : one was put down to steep in water — that one has, as you see, swollen to twice its bulk ; the other was immersed in saturated salt solution — that one has not altered in bulk. We thus see that salt attracts to itself water. It can, according as it is outside or inside, draw it out from or draw it into a moist menstruum. I have here in these three test-tubes another form of moist menstruum— cotton wool impregnated with egg-albumen. The plug — in each case a very tight plug — ^is, as you see, placed half way down the tube, dividing it into an upper and lower compartment ; and immediately below the plug I have a lateral hole (now sealed with plasticine).* Through this hole I can wash out l)Oth compart- ments very thoroughly, and fill and empty them without disturl)ing the plug. I have used in these experiments three fluids : a diluted egg-albumen with a specific gravity of 102(1 for my plug, and two extracting fluids — water, and a saline solution containing about 8 per cent, of common salt with a specific gravity of 1052. In Tiihe 1 I have water above and below ; in Tube 2 salt solution above and below ; and in Tube 8 water above and salt solution below. And here are the results obtained 24 hours after by emptying out the fluids and boilinff them secundum, artem. In Tube 1 we have in * In sealing with the plasticine care must be taken not to produce a positive pressure, and so dri7e albumen up into the upper compartment. 1917] on The Treatment of War Wounds 51 the fluid from the upper compartment a mere trace of albumen : in that from the lower a very massive floccular deposit. That means that in the upper only a mere trace of albumen has diffused upwards against gravity, and that in the lower compartment the heavier albuminous fluid has sunk to the bottom. In Tube 2, where both compartments were filled with salt solution, we have in the upper a Tube 3- 1 1 r ' 7 ^ H20 j 1 SpGI'VM I I 1 SpGll)52 -_J Fig. 11.— Tube 3 is flanked with test-tubes labelled A and B showing the result of boiling the fluid from the upper (A) and the lower (B) compartments of this tube. massive floccular deposit, and in the lower a heavy, but not nearly as heavy a one. It is the result in the lower compartment which specially interests us. It shows that an albuminous fluid is drawn down into salt solution in opposition to gravity. In the upper compartment we have, superadded to the drawing action of the salt, a displacement upwards of a lighter by a heavier fluid. In Tule 3 E 2 52 Colonel Sir Almroth E. Wright [March 9, (see Fig. 11), with water above and salt solution below, the upper compartment contains, as in Tube 1, only a mere trace of albumen. In the lower compartment we have again, as in Tube 2, a very heavy deposit of albumen drawn down against gravity. I have here other experiments of which I show you photographed drawings. All these bring out that when strong salt solution and water are brought into opposition, and we introduce such a succession of obstacles as are provided by a cotton-wool plug or a wick, we get, so far as the convection of fluids is concerned, the same results as when we interpose a thin membrane, such as parchment paper or NitCl y. Fig. 12. — The left-hand beaker contains water coloured with methylene-blue ; the right-hand beaker strong salt solution. The beakers are connected up by two siphon (J tubes — the upper being an open siphon filled with uncoloured water ; the lower a siphon plugged with cotton-wool and, like the upper siphon, filled in at the outset with uncoloured water. a film of formalin gelatine. With respect to the character of the fluid there is marked difference. Where we employ macroscopic pores albuminous substances are carried through ; where we employ only very minute pores we filter out al])uminous substances. In my next experiment (Fig. 12) we have in one beaker saturated salt solution and in the other water coloured with methylene-blue. To maintain the fluids at the same level we connect them up with a siphon filled with uncoloured water. We then esta])lish a further connexion by means of a siphon filled with uncoloured water plugged at the one end with cotton wool. This end goes down into the salt solution, but it is only just immersed. AViien we now Avatch events — 1917] on The Treatment of War Wounds 5^ and it is a question of watching them for weeks — we find that the coloured water is drawn up into the open limb of the plugged siphon in the manner shown. In the case of the open siphon nothing of this sort occurs. In the next experiment (Fig. 13) we have a series of three tubes W^ Fig. 13. — Tube A contains uncoloured water ; Tube B, water coloured witb metbylene-blue ; and Tube C, saturated salt solution. Thefluids stood originally at the same height in each tube. arranged tandem and connected up by wicks of moist l)andage fitting quite loosely in siphon tul)es. We have in Tube A plain uncoloured water, in Tube B water coloured with methjlene-blue, and in Tube C saturated salt solution — all these being filled in to exactly the same height, and then protected against evaporation. We now observe that the level of the fluid in C s-raduallv rises, while that in A and B 54 Colonel Sir Almroth E. Wright [March 9, sinks ; and at the same time the colouring matter from B is gradu- ally conveyed up the wick in the direction of C, but is not carried up in the direction of A. In the next experiment (Fig. 14) we have again a series of three tubes arranged tandem and connected up by wicks as in the last experiment. In A we have plain water, in B an albuminous fluid, £ p» i u .-> Fig. 14. — Tube A contains plain water, Tube B a watery solution of cKU-albumen, and Tube C saturated salt solution. and in C saturated salt solution — all hlled in to exactly the same height. As in the last experiment, tbe level of the fluid rises slowly in C and sinks away in A and B. AVe then unship Tabes A and C, add salt to A, and then boil both. We find that a great deal of albumen has l)een carried over into (', and that none has diffused over into A. 1917] on The Treatment of War Wounds 00 Th£ Setting Free of Trypsin by Hypertonic Salt Solution. You will probably not wish to see any further experiments on this point. But I have still to make good to you that a hypertonic salt solution sets free trypsin from pus and initiates digestion. On that matter I will content myself with showing you the two following experiments. Experiment 1.— I have here, as you see, two test-tubes filled nearly to the top with egg-albumen. To this was added J per cent, of carbolic acid, and the albumen was then solidified by immersing the tubes in boiling water. That done I took two cotton-wool plugs A 1 1 ! ■ j ^ i-\ } \ ^ j 1 C i Fig. 15. — Test-tubes filled with coagulated egg-albumen ; then plugged with cotton-wool impregnated with pus ; and then inverted into beakers. Beaker A contains hypertonic, Beaker B normal salt solution. and steeped them in a pus to which I had added h per cent, carbolic acid. I then inverted my tubes, the one into a beaker containing 5 per cent, salt, the other into a beaker containing physiological salt solution. (Fig. 15, A and B). To these also I added J per cent, of carbolic acid. You will understand why I chose carbolic acid as my antiseptic when I tell you that it is an antiseptic which does not destroy trypsin or impede digestion. You see in the drawings made after the tube had been incubated for 48 hours, that in Tube A (the 56 Colonel Sir Aim roth E. Wright [March tube which Avas immei-.sed in hypertonic salt solution) the egg-albumen was extensively digested, while in Tulie B there was only a mere trace of digestion. Experiment 2. — I here try to imitate the conditions of slough- covered wounds. I have in these beakers a foundation of coagulated white of Qgg containing 0*5 per cent, of carbolic acid. On the top of this I have in each case a disc of lint, woolly side up, fii-mly fastened down by adding another layer of egg-albumen and coagu- lating this by heat. Upon the lint I have poured a non-tryptic pus, giving, of course, an equal amount to each beaker. In this way I have made what I think can pass as a fairly close representation of Fig. 1G. — Beakers containing coagulated egg-albumen into which is imbedded a layer of lint. Upon the lint was poured pus, and upon this in the case of Beaker A hypertonic, and in the case of Beaker B normal salt solution. In Beal^er A the artificial slough has separated off l)y tryptic digestion. a pus-impregnated slouu'h tirndy adherent to the floor of ;i wound. (Fig. K;, a and B.) We now pour upon one of the artificial sloughs 5 per cent. ; upon another 0*85 per cent, solution made up with \ per cent, carbolic acid ; and we may pour upon a third Dakin's solution. AVe now place them all in the incubator. You see here what has happened after 24 hours. In Ikaker A, where the artificial slough has been treated with hy])ertonic salt solution, the slough has loosened itself from its l)ed, and floats up as I pour in water. In lieaher JJ, where I imposed only physiological salt sohition, the slough is still firmly adherent. And the same holds of llealcer C (not figured), where we have Dakin's solution. We have here, as you see, an instructive experiment. And we 1917] on The Treatment of War Wounds 57 can derive from it more instruction than has as vet appeared. In the tirst place, if we carry the experiment further, the slouirh which lias been treated with physiological salt solution will also separate. In contrast with this will be what will happen with the artificial slough treated with Dakin's solution. Here, especially if the Dakin's solution is periodically renewed, the clot will remain adherent. For the Dokin's solution, while it is destructive to leucocytes, is, when not quenched by albumen, destructive also to the trypsin which brings about the separation of the slough. We can always appreciate the situation and tell what is going to happen whether in the wound or in vitro by taking samples of the fluid and testing quantitatively for trypsin with milk containing about ^y per cent, of calcium chloride cryst., and we can when making experiments in vitro on the separation of artificial sloughs, hurry up the events by conducting the digestions at 50° C. We can also vary our experiment by leaving out the antiseptic. Then microbic growth will, more particularly in the weaker salt solution, proceed unchecked, and the destruction of leucocytes by that growth will play an important role in the loosening of the clot. Meanwhile, the microbes will be everywhere making their way deeply into the albuminous substratum. This imitates what is occurring in every untreated slough-covered wound. While on the surface sloughs are decomposing and separating, in the depth further tissue is becoming heavily infected and gangrenous. Since we cannot block the infection by antiseptics, we must place mechanical and biological obstacles in its path. That means we must get lymph to pour out in full stream from the deeper tissues, and attract leucocytes into those tissues. AVe may then, after the sloughs have separated, look to have a clean, comparatively lightly infected wound surface. TREAT3IENT OF THE WOUXD IN THE CaRE WHERE WE HAVE oxLY A Surface Ixfectiox. When w^e have got back to a clean and only lightly infected sur- face we must think out our next step. It will help if we first review what we have learned and get things into proper perspective. We have learned that there are in wound infections two supreme dangers. First, there is the danger associated with the buried infec- tion. We have appreciated that the effective and only remedy for this is the immediate opening up of the infected dead spaces. That, you will remember, is a question of converting a buried infection into a surface infection. The second very serious danger is that intensifi- cation of the surface infection which follows upon a lengthy inter- ruption of treatment during transport. This, regarded from the point of view of loss of life and limb, ranks next in order of import- ance after delav in dealino- with the buried infection. AVhen the 5.S Colonel Sir Almroth E. Wright [March 9, set-back due to transport has been prevented or remedied, we have confronting us the prol:>lem which, if treatment had been uninter- rupted, would have presented itself earlier — the problem as to how to treat a slight infection of a naked tissue surface. One procedure is to leave the wound to heal up from the bottom, limiting oneself to such re-dressing as would prevent erosive diges- tion. Bv this programme the patient would, when his wound is a large one, be condemned to very many months of disability and also of bacterial intoxication. For the fact has got to be faced that it is all but impossible to maintain satisfactory conditions in a large wound for months on end. The alternative programme is for the surgeon to close the wound with the minimum delay. If the anatomical conditions permit, and the bacteriological examination shows the wound surface to be practi- cally uninfected, or if the wound is only a very few hours old and the implanted microbes cannot yet have grown out, the wound can, after removal of all dead and foreign matter, be immediately closed — the surgeon, of course, standing by to reopen the wound if symptoms of buried infection develop. If, on the other hand, bacteriological examination shows that the wound surface is appreci- ably infected, or the history of the case makes this practically certain, we should, by closing the wound, be violating all the principle* of surgery. AVe should be converting a surface infection into a buried infection. The proper step to take with a wound which is appreciably infected is to reduce the microbic infection to the point at which it is negligible and then re-suture. Methods of DeaUmj with a Mkrobk Infection which Stands in th<- Way of Secondary Sat are. The nricrobic infection may 1)e dealt with by any one of the following procedures. In the /z'r.S'/! ^;/rt^;^ we can employ the physiological procedure. If we elect to do this, wc think out clearly the requirements. For ex- ample, it will be inap|)ropriate when dealing with a purely superrteial streptococcic and staphylococcic infection to continue the application of hypertonic salt solution. The effect of that would be, on the one hand, to bold off phagocytes from the microbes (for strong salt arrests emigration) ; and, on the other hand, to provide the staphylo- coccus and streptococcus with lymph, a fluid in which they can grow and disseminate themselves over the whole face of the wound. What we want is an application which calls out leucocytes, and which will restrain, or which at any rate will not activate, the lymph liow. Physiological salt solution, and zinc sulphate in I per cent, solution, and no doubt many other heavy metal salts in dilute solution, are the sort of agents we require. But what is, above all, essential to success 1917] on The Treatment of War Wounds 51) in physiological treatment of a surface infection is assiduity in re- moving any leucocytes which may break down upon the face of the wound. That is a question of maintaining intact the antitryptic power of the lymph on the wound surface. A second method of procedure — I may call it the unreasonlwj anti- septic procedure — is to employ an antiseptic, without laying stress upon the assiduous cleansing of the wound surface and the mainten- ance of good physiological conditions ; without inquiring whether the antiseptic can, when brought into external contact with pus or an infected tissue, penetrate into it ; and without asking whether the antiseptic hinders phagocytosis, or destroys the antitryptic power of the blood fluids, or permits or interferes with tryptic action. This unreasoning antiseptic procedure is constantly employed. It has led to failure upon failure, and it would be a matter for wonder if it did succeed. The third and last method of procedure I may call the combined antiseptic and physiologicat procedure. If we want to find a method of this sort we shall not find it by inquiring for it under this name. What we have to seek is a method which proclaims itself an anti- septic method and in this guise combats effectively, but perhaps not with full comprehension, corruptive changes in the wound. The method of Carrel is, as 1 think, such a method. I would propose to show that it is a comljined antiseptic and physiological method ; then to survey the results obtained ; and finally to consider how far the results should be credited to the antiseptic, and how far to the physiological, element in the treatment. We have in Carrel's treatment two factors : («) Dakin's antiseptic, or, as I should prefer to call it, Dakin's therapeutic agent ; and (&) Carrel's procedure for washing and refreshing the wound surface in the intervals between the complete dressings. Now each of these factors acts not only by killing or removing microbes, but by making the conditions in the wound unfavourable for microbial growth. Let me, taking first Dakin's fluid, and then Carrel's washing procedtire, try to make for you an inventory of their directly anti-bacterial, and their physiological or indirectly anti-bacterial, effects. Dakin's Fluid. Dakin's fluid is, as I have shown you,* a very ineffective anti- septic when it is brought into application upon microbes suspended in serum. It is also, as I have shown you, an antiseptic which has as good as no power of peneti'ating into albuminous fluids. It is also an extremely volatile antiseptic. Yv'hen exposed in a shallow dish at blood temperature I have found it to lose four-fifths of its "^ Vide supra, Experiments on Antiseptics. 00 Colonel Sir Almroth E. Wright [March 9,. poteiicv ill li;ilf-;iii-li()iii', ;iii(l iL will, as I liave already liacl occasion to ])oiiiL out, if not already (jnenclied by contact vvitli seruui, very (juickly disap])ear from tlic wound. Turning" from the effect exerted upon microhes to the cU'ect ex- erted upon tlie wound surface, let me recall to those of yon who have seen it, that when a nuked tissue surface is treated with Dakin's fluid (or for the matter of that with 5 per cent, salt solution) it is speedily converted into a bright coral-red granulating surface. That means it is converted into a defensi\'e surface excellently well provided with new-foi"med blood-vessels from which active leucocytes and fully potent lymph will emerge. I'hat is a physiological action to the good. But there ai'c also other effects exerted. Leucocytes are affected l)y Dakin's fluid. Ex])ei'iments show that it is destructive to phagocytosis. When we add one part of the reagent to nine of erxoafjvJar blood we I'educc; the ])hagocytic power of that ])lood by more than one-half. AYe abolish ])hagocytosis when we add one part of the I'eagent to four of 1)I()0(1. TIk; iluid elements of the discharge also are altered in cliai'iicLer by Dakin's iluid. Let me remind you here that we saw in oui' ex[)eriments on artificial sloughs that treat- ment with Didcin's solution hinders the digestive processes whicii bring about their separation. This stands in relation to the fact that the reagent exerts upon try])sin, when albumen is not there to act as a, buffer, a destructive action. We have here, as you perceive, a ]»hysiological action which may ((uite well come into oper;iti(»n when ii C()m])aratively clean but tryptic wound surface is flushed, Dakin's fluid abolishes also the antitiT])tic power of the l)lood fluids. It would seem, therefore, WMth one hand to give jn-otection, and with the other hand to take it away. ]^ut what really does happen is, 1 suppose, that trypsin and antitrypsin alike are destroyed by the flush and that afterwai'ds in the wound a new beginning is made. Let us follow up the train of thought here started. We may, I think, profitably ask ourselves whether if put to our election between maifitaining antiseptic action continuously at the expense of physio- logical action, and alternating antise])tic with physiological action, we should not do well to elect for the latter policy. And we may muse whethei" it was not specially felicitous to have employed, as Carrel has done, an antiseptic which is wry readily (|uenched and also very volatile, and to have applied it disconlinuously. Had that antise])ti(; been em])l()ye(l by a, method of continuous irrigation, phagocytosis on the face of tlie wound would have been excluded, and we might have; had in the cavity of the wound a lymph whose anti- try] >tic power had been desti'oyed. ]Uit I have already said enough about Dakin's fluid if you have appreciated that it is a i)ooi' antiseptic : tluit it acts as a poison upon leucocytes and blood fluids ; that its physiological action is a very com])licated one ; and that its beneficial effects cannot be due simply to its antiseptic action. 11)17] on The Treatment of War Wounds <:i CarreVs Method of Irri;ia(iii(j Hie Wound. I now come to Currers proccdiire of interailating between the complete dressings a fi'cqnenfc tlnsliing and refrcsliing of the wound surface and for carrying out this flushing unlaboriously. Allow me to say that we have here, 1 think, far the mosb iuiporbant contril)U- tion made to surgical technique since the beginning of the war. IJut to that let me add, that while Carrel's procedure gives us a new and improved technique for the application of antiseptics, much more does it give us a wavf and improved technique for physiological treatment. In all physiological treatment the assiduous removal of corrupted and corruptil)le discharges is the primary desideratum. We now return to the results of the treatment of infected wound surfaces by Carrel's method, and we may take them from Carrel's book. But it will he well, in order to keep to the kind of wound infection here under discussion, to exclude from consideration wounds complicated with fractures — ^for in those effective washing is difficult. And we may further, looking to the classification of wounds of soft parts in Carrel's book, exclude from consideration his class of phlegmonous and gangrenous wounds, and his class of suppurating wounds. These would correspond to wounds which have, through postponement of treatment or its interruption by transport, suffered a set-back, converting an originally light surface infection into a heavy infection with invasion of the deeper tissues. There would then fall within our purview only his class of fresh wounds of soft parts taken in hand when 5 to 24 hours old. And we learn from the data he gives with respect to these that, where there are sloughs, 15 to 20 days, and, where there are none, 5 to 12 days are required to prepare the wound for secondary suture. That gives us a measure of what can be done by what I have, I hope not without good warranty, called Carrel's " combined antiseptic and physiological treatment." . Let us consider what Carrel's results tell us. They tell us in the first place that, whatever else it is. Carrel's treatment is not in any sense a therapia magna sterilisans. Regarded as an antiseptic method, it is a method of "'fractional sterilisation " requiring for the case we are considering — the simplest case of all — at the rate of 12 douches a day a series of 00 to 144 antiseptic douches. And if I am right in regarding Carrel's treatment as a combined antiseptic and physiological treatment, we have, superadded to the antiseptic, a series of 60 to 144 physiological attacks upon the microbes — each such attack starting from an atryptic condition. The consideration of these figures leads directly to what I have to say in conclusion. While Carrel's work constitutes a very notable practical achievement, regarded as science it comes short in the respect that adequate control experiments are lacking. I do not r.2 rThe Treatment of War Wounds [^March 'J, mean tliat it lias not Ijeeii (.lenionstratcd tliat Carrel's treatment aceomplishes what was impossible by the old system of syringing with antiseptics and leaving the wound afterwards to fill with pus. The inefficacy of that older treatment was attested by tens and hundreds of thousands of control experiments. What I mean is, that we have not in Carrel's work any control experiments with more potent and penetrating antiseptics to negative the idea that with these one could with less than 60 to 144 consecutive douches convert a light surface infection into a negligible one. And again, we have not from Carrel any control experiments with a well-thought-out physiological treat- ment to negative the idea that one could achieve a similar sterilisation by GO to 144 successive physiological attacks upon the microbes, starting each time from an atryptic condition. If we would abide in the spirit of science, every unwarranted assumption must go. We must not assume that when we have successfully combated a surface infection by a series of 60 to 144 therapeutic operations we have reached finality. And much less must we, from the fact that a treatment successfully combats surface infections, infer that it is also an effective treatment for infections which penetrate into the deeper tissues. Rather ought it to come home to us that it is impossiljle that there should, for quite different categories of wounds, i.e. for quite diverse conditions, be any one routine treatment. [A. E. W.] 1!)17] Scientific Forestry for the United Kingdom 63 WEEKLY EVENING MEETING, Friday, March 16, 1917. The Hon. R. Clerk Parsons, M.Inst.C.E., in the Chair. Sir John Stirling Maxwell, D.L. Scientific Forestry for the United Kingdom, My object is to convince you of two things : first, that we require more woods in the British Isles, and, secondly, that it is useless to make them except on sound scientific lines. I shall take the second proposition first. It is not the logical order, but it will be Ijetter to have the nature of the work in mind l)efore considering whether it ought to be undertaken. To many people the planting of woods appears so simple a thing that they wonder what part science can play in it, especially when they remember that the grandest forests in the world are the work of untutored Nature. They forget that Nature has been perfecting for ages the intricate machinery of these forests. When man dares to embark on the task of transforming bare ground into forest, he can only succeed Ijy studying Nature's methods, and this is precisely what science does. When I speak of science, please don't conjure up visions of musty Ijooks, glass cases, dried specimens, and professors dictatino- mathematical forrnuUe. Think rather of foresters, eager in eye, brain and hand, living and working in the woods, comparing notes with one anotlier, and \aluing science precisely as they value spade and axe because it is an indispensable tool for their everyday work. Now just as forest tools have to be of good metal, so there is no room in the forest for slipshod science. Forestry, whether as a science or an art, must needs rest on the study of botany, geology, entomology and mathematics. From each of these it receives direct help. But it is more than a mere resultant of these sciences. Its peculiar study is the complex life of tree communities, its practical aim the production of the largest amount of good timber on a given area in the shortest possiljle time. Before we consider examples of scientific method applied to forestry, I want you to grasp the extraordinary contrast between the position it holds in this and other civilized countries. In other countries forestry is classed with agriculture as one of the foundation industries on which the security of nations depends. Ifc is an industry which the State has taken specially under its wing for two reasons : first, because large tracts of wood belonging to the nation (14 Sir John Stirling IVlaxwell [March 16, or sovereign give the State a direct interest in its success ; and, secondly, because it is recognized that an industry which is out of scale with the span of human life stands in peculiar need of encourage- ment and guidance, and really concerns the State as it never can concern any private individual. This last factor of time lies so close to the heart of the subject that we may consider it a little more closely. When some one writes a bool^ of the psychology of different occupations, he will recognize in the forester a man who is so much outlived by the crop he cultivates that it becomes a second nature to him to think and plan outside his own lifetime — a man who can seldom hope to see, even in old age, the full result of what he begins as a boy. Sad ? Yes ; and foresters hate dying more than most people, i3ut such work is inspiring. You do not pity the astronomer peering out into space or the historian diving back into time because their feet cannot follow their thoughts. You need not pity the forester Ijecause his job is bigger than himself. But certain practical difficulties attach to the cultivation of so slow a crop, and these must be faced. When seventy to one hundred years elapse between seed time and harvest, scientific cultivation is no easy matter, and early mistakes are paid for very dear. Still more severe are the financial trials. Consider the case of new ground to be planted. The man who plants may lock up his money for seventy to one hundred years, lose the rent of his land, and, in addition, have to pay rates and taxes and cost of maintenance for a property which cannot bring in a penny until such time as the sale of thinnings may help to defray these charges. The cleverest prospectus could not make this invest- ment tempting to beings whose years are but three score and ten. Or take the case of a forest inherited as a going concern, Ijringing in a regular annual income as each block is cut and replanted in suc- cession. By increasing the fellings and scamping the work of replanting, the owner can at any moment double the income for his own life at the expense of his successor. You see the point ? A man may have many motives for planting or maintaining woods, but they are not the ordinary motives which, whether we like them or not, are the mainsprings of ordinary commercial effort. These con- siderations, together with the desire to make the most of woods under its ow^n control, have led the State in every country, from France; to Japan, to regard the care of forests as one of its primary duties. Here the State has for several generations Ijeen innocent of such ideas. Let us see why. We have, for reasons which will appear later, no natural forests of consequence, while the forests belonging to the Crown are few and comparatively small. Yet a hundred years ago the principles of sound forestry were ])oth understood and practised in this country, and we Avere little, if at all, behind our European neighbours. In the period of vigorous and enlightened rural development which marked the end of the eighteenth and 1917] on Scientific Forestry for the United Kingdom 05 beginning of the nineteenth centuries, forestry played a considerable part on most private estates, ^vhile the Government, deeply concerned in the supply of oak for naval construction, made that the main object in the management of the Crown Forests. Then, quite suddenly, British forestry fell into oblivion. With the substitution of steel for wooden ships, the Royal forests lost their importance and turned into national playgrounds. The cheap importation by steam of first-class timber from virgin forests overseas rendered the culti- vation of coniferous wood unprofitable, and indeed unnecessary, except for shelter and beauty. In countries less open to the sea and dependent on wood for fuel these changes passed almost unobserved ; here they conspired, with our numerous ports, ample shipping and abundance of coal, to work a complete revolution. Industries are curiously fragile things. Like virtue, they grow in use, but in repose quickly drop to pieces. The return of suitable economic conditions is not enough to revive them. It was not many years before the price of timber rose again, but in the interval the art of growing and marketing woods had been forgotten. Elsewhere the State would have seen to its revival. Here, as I have shown you, the necessary tradition was unhappily wanting. Having seen why we are behind other countries in this industry, let us learn from a few examples how science can help the forester. You will bear in mind that abundance of straight timber is the forester's object. He obtains it by exploiting the wonderful adapt- ability of trees to their surroundings. An oak standing alone in the open bears little resemblance to an oak grown in a dense wood. This latter may have a clean stem 60 feet high, while in the other it would be difficult to find 10 feet of straight timber. The same thing holds true of other trees. It is the upward struggle for light of trees growing close together that produces fine timber. It is the forester's task to initiate, watch and control that struggle. Let me take the case of a new plantation, in making which a Scots laird had the good sense to give a free hand to the experienced adviser he consulted. AVhat did the adviser do ? First, he examined an adjoining oak wood, J^elieved to be 150 years old. He had a tree felled, counted the annual rings, and found its age to be barely 100. Oak, he said, is the tree for this exceptionally good oak soil. How was it to be planted ? When a well-stocked wood is felled the soil is clear of weeds and easy to plant, being covered with the dark leaf mould, which is a precious asset of well-managed forests. But in the case I am describing a thick turf of old grass, very unfriendly to young plants, had to be reckoned with. The land was therefore ploughed and sown with oats and acorns. When the oats were cut the seedling oaks remained uninjured among the stubble. Two years later small plants of beech were sparingly added, and 800 larches to the acre, planted in rows. This plantation has never looked back. What has happened is exactly what was intended to happen. The larches Vol. XXIL (No. Ill) f GQ Sir John Stirling Maxwell [March 16, have shot ahead, encouragiiiu' the upward tendency of oak and Ijeech. Two points required attention. The larch had to be lopped back where it encroached on its neighbours, and it had to be removed, altogether before it checked their growth. Part was removed two years ago, the rest this year. It was sold for pitwood,and, having at the present abnormally high prices realised £16 an acre ten years from planting, it will suffice to defray the cost of making the plantation. The oak and beech, already more vigorous than in carelessly made plantations, will henceforth grow together, with occasional thinnings, till the final felling, high forest of oak being the objective, in which a certain proportion of beech will be retained to carpet the floor with its rich fall of leaves. This example neatly illustrates one feattn-e of forestry which is often forgotten. There is no occupation in which it is so easy to squander labour, and none in which a little labour applied at the right moment goes so far. It was not enough to make this plantation after a good design. Had either of the simple precautions I have mentioned been neglected, the result would have been a poor larch wood instead of a promising Avood of oak. We will take our next example from one of the Crown Woods. These woods, after long years of neglect, now rind themselves once more under energetic and skilful management, thanks mainly to the foresight of the late Sir Stafford Howard. This photograph shows how the Crown Foresters in the Forest of Dean seized the chance of a good acorn year to restock an old wood without the expense of replanting, removing the parent trees before their shade began to injure the seedlings, and rigidly suppressing the hostile rabbit. How simple, you say. Yes, very simple, when you know how it is done ; and yet, if you ask me to show you another naturally regenerated oak wood like this in Britain, I do not know where I should be able to find . one. In France they may be seen wherever the oak is grown. Even the period of neglect had good things to show now and then. Here, for instance, in the Tintern Woods, purchased by the Crown sixteen years ago, are larches planted as standards among oak coppice. This was good forestry. The forester seized an opportunity. A pure plantation of larch would not have produced stems so large and so free from the omnipresent canker. Our next example is a pure larch wood in the same forest, which has been left too long untliinned. The foresters are here studying a knotty problem. This wood, about fifty years old, is not full grown, but is worth a lot of money as it stands. It cannot be left alone. The crowns of the trees are so small that unless they are given room to expand they cannot assimilate enough food to make any substantial increase to their stems. A section of one of these trees would show annual rings diminishing in thickness since the to|^ became too crowded. After thinning, the annual rings of the remaining trees would quickly 1917] on Scientific Forestry for the United Kingdom 67 expand, the value of the wood increasing every year with their diameter. Now in thinning a wood Uke this there is grave risk from wind, and it is a ni:e question whether it would be wiser to fell the whole thing now and realise the present value, or thin it in the hope that the remaining trees will maintain their footing and grow into heavy timber. The decision will depend on many things besides the condition of the wood itself. A forest must give a regular yield of timber year by year^ and must therefore contain woods of all ages. At Tintern woods of this age are scarce, and the Crown Foresters are anxious to preserve this one if they can. They are leaving nothing to chance. You see them in this photograph examining a sample block, every tree in which is numbered, entered in a book and measured at regular intervals. They are trying various methods of thinning in various plots, and they know to a square foot what increment each is producing. Twenty years hence there will be some noble stems here provided the wind spares them. You will hear people say that we are more subject to wind than our Continental neighbours ; I do not think this is true. The Continental foresters take care to guard against the dangerous winds, and all their plantings and fellings are designed with this object. AVhen these plans are disturbed the wind makes havoc. In the Eberswald, near Munich, a few years ago great stretches of the forest were destroyed by the nun moth, and had to be felled out of their order. The wind found entrance, and 2000 acres were laid flat in the gales of the succeeding winter. I pass now for a concluding example to quite another type of work — the planting of waste land — and ask you to accompany me to a loch in Inverness-shire 1270 feet above sea-level, and close to the watershed of Scotland on its western side. Here, in plantations begun twenty years ago, we may learn something about the limits to which afforestation can be carried. In order to secure tlie forest area required with the least disturbance to other interests, it will, as a rule, be necessary to devote whole subjects to afforestation, that is to say, whole sheep farms, deer forests, or whatever the subject may be. No one proposes to plant arable land, but any such land attached to the forest subjects will be required to provide holdings for the forest workers. Even if the most suitable subjects are chosen, the whole area will seldom be of equal value, and it is important that the high and poor ground should not be wasted if, by taking pains, it can be made to grow good timber. The ground in this case was poor glacial drift covered with peat, in which were imbedded the roots of vanished forests of Scots pine. The only surviving trees were birch, mountain ash, black alder and bird cherry, with a few willows, all sadly distorted by snow. The new plantations were made with good advice, or rather, with advice which would have been good elsewhere. Here it was not good, because it had not correctly gauged the problem to be solved. Xo one doubted that the Scots pine was the best t'-ee to plant. Accordinglv it formed the matrix of the plantations, larch F 2 68 Sir John Stirling Maxwell [March IG, being introduced where the ground was suitable, with common spruce in the wetter places, and here and there groups of various American and Japanese conifers. The result was a conspicuous failure. Then the owner began to make discoveries. He heard of a plan devised by the Belgian foresters for planting the high moors near Spa. He went to Belgium to see what they were doing. The first thing he learnt was that the Belgian foresters had discarded the Scots pine as hopeless for this sort of ground. They showed him a plantation of this species forty years old and less than 20 feet high, the failure of which had long deterred the Belgian Government from making any more plantations in that region. Then they showed him a flourishing spruce wood which fringed the same moor. Can the soil, they asked, be good on one side of that straight fence and bad on the other ? Is it not clear that the' spruce, if only you can get it established, will grow on this moor though the Scots pine will not ? iSow in the Inverness-shire plantation the spruce had been reckoned a failure even among the failures. True, after ten years of obstinate sickness, its complexion had slowly changed from yellow to green, and it was beginning- here and there to add a few cautious inches to its stature, but at that rate forestry brings neither pleasure nor profit, and the owner and his forester had given up the spruce as a bad job. Not so the Belgian foresters. Once assured that the spruce would grow, they set about devising means to establish it quickly, and this is the system at which, after many experiments, they arrived. The ground had to be drained. A large turf taken from the drain was laid on its back in the place where each plant was to go. When the time came to plant, a hole about the size of a No. 4 flower-pot was cut in each turf with a trowel-shaped spade. In this the plant was placed with two handfuls — small handfuls, for the planters were women — of sand or gravel mixed with basic slag in the proportion of 7 of sand to 1 of slag. I cannot tell you why, but the plant derives no benefit from the slag unless it is mixed with mineral soil. The quantity of manure is very small. It tides the tree over its initial difficulties, so that it makes and ripens a good grow^th the first year, while the turf keeps it clear of weeds. Possibly it assists the development of friendly bacteria in the soil. The decaying turf and herbage beneath avail to support the young plant over the second year. The third, it begins to take hold of the ground, sweetened by this time by the action of the initial draining. I cannot show you photograplis of this work in Belgium, but I can show you the faithful imitation in Scotland. Sitka spruce, a tree from the western coast of North America, was the species employed in this case. The trees were planted as two-year seedlings about 3 inches high. Two years later they showed some progress. In five years they began to get into their stride. Now, in the eighth year from planting, many of them are 10 feet high and beginning to make rapid growth — a fair result on poor soil and 1300 feet above the sea. 1917] on Scientific Forestry for the United Kingdom G9 The common spruce, which alone is used in Belgium, responds well to the same treatment, thouiih it does not grow quite so rapidly. The use of manures in forestry may serve as a sample of questions which await investigation. The views of British foresters on the subject are vague aud inconsistent. Xearlj all use manures in one form or another in their nurseries. Nearly all are opposed to their use in planting. Some will tell you that they have no effect, and it is, indeed, very easy to apply them in such a way that they can have no effect. Others will tell you that their use is radically unsound, because they are soon exhausted. Does it matter how soon they are exhausted if they have done their work ? Who grudges the motor a turn of the handle at starting ? I have in my mind an experiment in which a few handf uls of sand mixed with basic slag were applied to certaiu rows in a plantation, once more of Sitka spruce. The manured trees are now 10 feet high, while their neighbours, left for comparison without manure, are less than 2 feet. The recovery of these last, I believe, to be only a matter of time, but they will always be five to ten years behind the others. In forestry time is money. People imagine, very naturally, that the native trees must be better suited to our soil and climate than those imported from other countries. That view is held on the Continent of Europe with some reason. As regards this country it is quite mistaken, and is especially untrue of the conifers, which concern us most, since nine-tenths of the timber we consume is coniferous. In the glacial period the ice banished all vegetation from this part of Europe. When plant life returned after the retreat of the ice, only three conifers came back to what are now the British Isles— the Scots pine, the yew and the juniper, of which but one, the Scots pine, has any forest value. Probably our climate was then drier and warmer, and therefore better suited for the Scots pine, and less suited for other conifers than it is now. We all love the native pine for its beauty. It still grows well in the eastern counties from Norfolk right up to Cromarty Firth, though not so well as in the drier climate of Saxony. Here and there fragments of the old forests still fledge the Scots hills. But on our western watershed the tree is undoubtedly dying out. In large areas where it was once common it has completely disappeared, no trace remaining except in place names and roots embedded in the moss. Yet in the unobservant forestry of the nineteenth century, when high or bare ground had to be afforested, this tree was per- sistently planted simply because it was indigenous. Its failure has given such enterprises a bad name. The larch, spruce and silver fir, exotics from the mountains of Central Europe, are all better for such work. These trees, and still more the conifers from the western coast of North America, grow good timber at altitudes which are quite beyond the reach of our native pine, and it is possible that others from Japan and Western China will succeed as well. 70 Sir John Stirling iViaxwell [March 16, 111 the plantations of which I have been speaking^, the Scots pine is broken by snow and browned by spring winds which deprives its fohage of moisture, which the roots cannot replace while the ground is frozen. After twenty years' growth it is not more than 20 feet high, and often less. The height growth of Sitka spruce and Nobilis fir is nearly double. Their branches bend to the snow and decline to yield their moisture to the east wdnd. They stand uninjured among the debris of the pine. The Nobilis fir is a tree specially adapted to moorland planting, because it hates lime and thrives on peat. In any scheme of afforestation deserving to be called scientific, one of the first steps will be thoroughly to test the value of the newer exotics as agents capable of extending plantations to soils and elevations which it would be useless to plant with our native trees. In nothing has the unscientific character of recent forestry in this country been so conspicuous as in its relation to exotic trees. The spruce and larch have been with us since the 17th Century, but even now their habits are still very far from being generally under- stood. The larch is essentially a mountain tree, only growing vigorously Avhere the soil is stony, the drainage quick, and moisture, whether from rain or melting snow, abundant in spring. It has been planted in this country by the million in situations as unfriendly to the tree as they are favourable to its enemy, the canker fungus. "What disappointment would have been saved if we had taken a hint from the French, who never emj^loy it except on the stony slopes of their mountains. The spruce, as we usually see it in this country, is a tree of no value, because the wood is full of knots. Properly grown in close plantations it produces a very large volume of light, easily worked timber, which is in constant demand and which, creosoted, makes good railway sleepers. It can be grown to perfection in England, Scotland and Ireland, as may be seen in the photographs which adorn the noble volume of Mr. Elwes and Dr. Henry. Yet if you search Britain from Land's End to John o' Groats I doubt whether you will find more good spruce woods than you can count on your fingers. The Douglas fir has been cultivated here since 1827, but well grown woods of it are still scarce. One of the oldest and best known, at Taymount in Perthshire, is only fifty-seven years old, and grows on soil far from ideal. At Benmore in Argyllshire there is a much larger Avood, planted thirty-seven years ago on ground very steep and rocky but evidently congenial. These suffice to prove that the species can on suitable sites yield heavy crops of good timber in a shorter time than any other tree. The Sitka spruce, introduced in 1831, has not yet been tried on so large a scale, but promises results equally remarkable. At Craigo in Forfarshire there is a group sixty-six years old and well over 1917] on Scientific Forestry for the Unite:! Kingdom 71 100 feet lii,£rli, with tall cylindrical boles 10 feet in circumference. A tree of the same species at Mnrthly in Perthshire was measured independently in the autumn of iDlG^by Dr. Henry of Dublin and Mr. Jackson of Kew, and proved to be 126 feet high and 1?4 feet in girth. Another at Stanage Park in Wales, growing 800 feet above the sea, is reported by Mr. Ptodgers to be now 124 feet high and 12 feet in girth. Yet this is a tree which many foresters still hesitate to plant because frost often checks it in youth. Its power of recovery from such attacks should reassure the most timid. If the leading shoot is destroyed it promptly turns up a side branch to form a new leader. These excursions in the woods have left us little time in which to discuss the reasons why a policy of afforestation has become a national necessity. Argument is almost superfluous after the Prime Minister's statement in the House on February 23, 10] 7. He told us plainly that timber absorbs more shipping than any other import ; that the situation is in consequence very grave ; that in the effort to reduce imports the problem of timber must be attacked before any other. The fact is that dependence on imported timber has in this war been like a millstone round our necks. In some cases, as the late Prime Minister pointed out in a speech to the miners, we have only been able to obtain it from neutral countries on condition of sending coal in exchange. Beggars cannot be choosers, or such a condition in time of war would ne^er have been tolerated. You will notice how the German Chancellor in booming the submarine blockade invariably couples timber with foodstuffs. He has every reason to do so. In increased prices, freights and insurance, and cargoes sunk, Ave have already wasted in the last three years between thirty and forty millions of money on imported timber. The timely expenditure of a fourth of that sum, beginning seventy years ago, would have established in this country all the woods necessary for our security. The French forests are suffering, and must suffer, because we have failed to take the precautions long ago taken by every other country. Only thus can the wants of our Army be supplied. Again, all through the war the Welsh coal-mines have been indebted for their pitwood to the foresight of our Allies in afforesting the waste lands of the Landes near Bordeaux. Have we, you will ask, made full use of the timber growing in this country ? That question cannot be answered till the end of the war. So little was it considered at the beginning that we had been at war more than a year before steps were taken by the Govern- ment to encourage the use of home-grown timber. By that time half the skilled woodmen had gone to the Army. Their places have to some extent been taken by regiments of Canadian lumbermen, which are working in this country for the Government. We have much to learn from them, especially in the matter of transport. With more labour the output from the home woods might have been much 72 Sir John Stirling Maxwell [March 16, larger. It is only fair to say that no one foresaw what enormous quantities of timber would be consumed by modern military opera- tions, and that there existed no reliable survey of the timber available. K"o survey has yet been made, nor has any record been kept of the amount felled. Under these conditions it is idle to speculate how much remains. AVe can see that the quantities of standing timber, especially of pitwood, are happily still considerable. Perhaps it is lucky that they were not tapped earlier, since all that remains may be wanted. One is driven to the conclusion that the least we can do in the interests of national safety is to increase our area of wood sufficiently to make the country independent of imports for at least three years in an emergency. These islands, in proportion to their size, have less th5.n one-fourth of the woodland possessed by France and Belgium, less than one-sixth of that possessed by Germany. In making our- selves independent of imports for a short period we are not confined by the rule wdiich limits the annual fellings in the forest to a volume equal to the annual growth. We can, in an emergency, at the expense of the future, but without devastating our woods, make in three years the fellings which in normal times would be spread over fifteen. On this basis, the addition of a million and a half acres to our existing woodlands would be sufficient for safety, assuming that the areas felled during the war were replanted and kept properly stocked. Even so, we should still be poorer in timber than any other European country, except Portugal. A danger period is inevitable, when we shall be very vulnerable by any power which can cut off overseas' timber. Every year we delay making provision is a year added to that period. Though the experience of the war will no doubt supply the principal motive for adopting a policy of afforestation, there are two other considerations, either of which might well be conclusive. The first is the precarious nature of the world's supplies of coniferous timber even in time of peace. The consumption of this class of timber is steadily increasing all over the Avorld. For nine-tenths of our supply we depend on the virgin forests of foreign countries, which are rapidly Ijeing depleted. Unless a radical change comes over the management of these forests, and especially unless the ravages of fire are checked, timl)er will be very difficult to procure in sufficient quantities seventy years hence. Steps to meet that emergency must be taken at once. Unless the forests of Canada can be safeguarded and made available, provision will have to be made in the United Kingdom on a much larger scale than that indicated above. The other consideration is perhaps more in harmony with the aspirations of the moment. These islands contain vast areas of rough pasture little l^etter than waste and almost uninhabited. Can no better use be made of them ? Every European country has been faced by this question, and every country but this has long ago found 1917] on Scientific Forestry for the United Kingdom 73 the answer in afforestation. A scheme such as I have indicated ■would not absorlj by any means the whole of the rough pasture, and probaljly not even more than a quarter of what is plan table, but the method of carrying- it out would require most careful thought. The knowledge of forestry in this country resides partly in experts employed by the Government and teaching centres and in the officers attached to the Crown Woods ; but to a large extent, and perhaps in its most practical form, it resides in the owners of private estates and their foresters, who are responsible for 07 per cent, of the woods in this country. We have seen that the great risk attending privately owned forests is the temptation to sacrifice the future to the present, to secure an immediate gain at the expense of great eventual loss. The State does not usually excel in economy, but the experience of other countries shows that it can, on the whole, conduct forests better than private individuals. Thus in France and Germany the produc- tion is found to be greater in the State forests than in private woods, while the communal woods, managed by the State for the villagers with many concessions to their wishes, stand halfway between. The situation seems to point to a double advance on parallel lines — first, the acquisition and planting of land by the State, and, second, the encouragement of planting by private individuals, in return for some guarantee that their woods will be properly maintained. What does encouragement mean ? It means skilled advice in the making of working plans and schools where working foresters can be trained. It also means that in some form or other the State will have, for some years at least, to make up the difference between loss and reasonable profit on private plantations. It is impossible now to calculate how far plantations made after the war will pay. The conditions do not appear favourable. Prices, bank rate and wages are the chief factors, and all are uncertain. One thing only is certain — that the nation must have the woods necessary for national safety even if it has to pay for them. Quite apart from the direct profit or loss, the indirect gain to the nation by afforestation will beyond doubt be very great. It is inevitable that private individuals should mainly be guided by the question of profit or loss, but this is the only country in which the State has regarded afforestation wholly or even mainly from this point of view. In other countries, not because they are less business- like, but because they are more businesslike, the motive for afforesta- tion has been found, not in the hope of direct profit, but in the increased productiveness of the land under forest and the increased population it is able to support. Some people find it difficult to keep these questions distinct, but they really are so. Whether a wood is profitable or the reverse to a planter there is no shadow of doubt that it enriches the nation. Provided it grows reasonably well, each acre will produce annually a ton of timber : every 100 acres will support a family ; for every £100 of timber sold standing an 74 Scientific Forestry for the United Kingdom [March 16, equal sum will be paid in wages for its felling and conversion. To ascertain the value to the State of the plantation, this state of things must be compared with the rough grazing where a single shepherd is employed to 500 or 1000 acres, and the annual production of each acre seldom exceeds 5 lb. of mutton and | lb. of wool, or with the deer forest which produces about 1 lb. of venison per acre. There are three matters which must be taken up in advance of afforestation, and I trust public opinion will support the Government in getting to work on them at once, without waiting for the end of the war. The first is a survey, to ascertain the best forest sites ; the second, the provision of plants in large quantities ; the third, the training of forest officers. The last is the most important of all, since scientific method is the first condition of success. [J.S.M.] 1917] Mr. Edward Clodd on Magic in Names WEEKLY EYENIXa MEETING, Friday, March 2n, 1917. Sir William Phipsox Beale, Bart., K.C. M.P. F.C.S., Yics-President, in tbe Chair. Edward Clodd, J. P. Magic in Names. Amoxci all lower races, and among the superstitious in higher races, there is f onnd belief in a vague, impersonal power which acts through both the living and the non-living. It is the stuff through which the sorcerer, whether deceiving or self-deceived, exercises control over persons and their belongiugs to their help or harm, and also control over invisible beings and occult powers. As black magic, it works maleficently ; as white magic, beneficially ; in each case through both the tangible and the intangible. The savage beUeves that the sorcerer can cast a spell upon him through his nail and hair cuttings, his saliva, his blood, portrait, etc., and through the intangible, as his shadow, reflection, and, notablest of all, his name, which to him is an integral part of himself. Hence the world-wide custom of name-avoidance ; the precautions to conceal the name and, vice versa, the dodges to discover it ; hence, also, the taboo on the names of relatives, of the dead, of sacred persons and of spirits, through ascending stages, to the high gods. From birth to death the name-taboo works ceaselessly. Sanctity or secrecy attends the ceremony of name-giving. Borneans, Lapps change, and, in ancient times, Jews changed, the names of the sick to deceive demons or to elude death ; but it is in savage initiation rites, which have been called " the lineal ancestors of confirmation," that the giving of a new name is found to be common. On arrival at puberty the youth is sent into retreat and is re-named ; as with the Roman Catholic and Buddhist monks, and with the nun who takes the black veil, the old name is effaced and a new name is taken. The name as a part of the person has amusing example among the Kwakiutl Indians of British Columbia. A man in debt can put his name in pawn, remaining anonymous till he pays up. Believing that luck or ill-luck attaches to certain names, Scotch fisher-folk use all sorts of roundabout names for their catches, cor- responding to which are the euphemisms which barbaric huuters apply to their quarry, and Malayan miners to metals in the belief. 76 Mr. Edward Clodd on Magic in Names [March 23, e.g., that tin is alive and moves abont, and must Ije called bv another name to obtain it. A like belief in their personality explains the propitiating and flattering names applied to diseases, as when the Borneans call the smallpox "jungle leaves," and when the Slavs call the fever demon " godmother." In family life the name-taboo is active ; people related by blood or marriage, notably in tbe case of mothers-in-law, avoiding mention of one another's names. But it is with the ascending rank of persons- that the taboo gathers force. From the Far East to Dahomey there prevails the custom of speaking of emperor, king or chief by some other name than his rightful one ; and the Hke applies to priests. World-wide is the prohibition or the reluctance to name the dead, lest thereby their ghosts should appear, the bereaved sometimes changing their own names so as to baffle the ghost should he return. A group of folk tales, exampled by the German " Rumpelstilzchen '' and the Suffolk " Tom-Tit-Tot," have at their core the barbaric belief that if the name of the demon can be found out he becomes power- less, and the like applies to the gods. Ba, the Egyptian sun-god, lost his power when Isis beguiled him into telling him his secret name. The name of Bome's tutelar deity was kept secret as her safeguard, and to this day it remains undiscovered. Chaldean and Jewish books of magic teem with formulae concerning the mystic names of the god, and only four years ago a number of monks were ejected from Mount Athos for holding the heresy that God's name is a part of Himself. Among the ancient Jews severe penalties were attached to the utterance of the name Yah we, or Jehovah, and in Moslem belief Allah is only an epithet for the god's name. On the other hand, magic power is wrouglit through the invocation of the sacred name. To this the Gospels bear witness in their reports of the expulsion of demons and the healing of the sick in the name of Jesus, and the Early Fathers of the Church record what wonders were performed in the name of the Trinity. To the survival of this belief, cure-charms, inscribed amulets and the like supply proof. What magic power is believed to inhere in Avords themselves detached from persons has example in the creative formula, notably in the Egyptian, whereby the god comes into being by uttering his own name, and in the Hindu, the power of the "mantram" being such that it can enchain the gods or make them tremble. Only by mystic passwords can the soul, accoixling to ancient Egyptian belief, secure admission to dwell with Osiris triumphant, and if by mishap the dead man's name be lost, he becomes extinct. The survey of a sul)ject which can draw examples from every grade of culture brings home the fact of the persistence of primitive ideas, and adds its crowd of witnesses to that continuity of the spiritual which has its correlate in the phvsical. [E. C] 1917] Recent Developments of Molecular Physics WEEKLY EVENING MEETING, Friday, March oO, 1917. CoLOXEL Ed^iond H. Hills, C.M.G. R.E. D.Sc. F.R.S., Secretary and Vice-President, in the Chair. J. H. Jeans, M.A. E.R.S. Recent Developments of Molecular Physics. As the subject of my discourse this evening I propose to take the surprising developments in the fundamental conceptions of physics \Yhich have been forced upon us in the last few years. In the closing year of last century, Lord Kelvin delivered a Friday evening discourse, taking as his title " Nineteenth Century Clouds over the Dynamical Theory of Light and Heat." He said : " The beauty and clearness of the dynamical theory which asserts light and heat to be two modes of motion is at present obscured by two clouds." The cloud over the dynamical theory of light centred round the question of the motion of the earth through the ether ; that over the dynamical theory of heat was concentrated about the famous theorem of Equipartition of Energy. In the seventeen years which have elapsed since then, the attempt to remove these clouds has led to the introduction of two new principles — or perhaps it is better to speak of them as theories, since they are both still in a tentative stage. The Theory of Rela- tivity has been introduced to remove the first cloud, and the Theory of Quanta to remove the second. These are, perhaps, the two most revolutionary theories that have been seriously considered by science for some centuries. They are revolutionary especially because they involve a new philosophical and metaphysical outlook which implies a complete break from that formerly held. It need hardly be said that the new theories are still very far from having achieved universal acceptance, but whether they ultimately prove to be true or not, the mere consideration of them has beyond dispute done a great deal towards suggesting a way out of the impasse in which molecular physics found itself at the end of last century. The two clouds of which Lord Kelvin spoke are not yet completely dissolved, but rays of light are appearing here and there, and the vista beyond, interpret it in any way we will, is certainly one of the most interesting and fascinating that has ever spread itself before the physicist. 78 Mr. J. H. Jeans [March 30, Let US begin with a very brief consideration of the first cloud. The astronomical phenomenon of the aberration of light is known to all. To catch the light from a given star, the astronomer must not point his telescope towards the position of the star, but in a direction obtained by compounding the velocity of light with the velocity of the earth in space. The principle is substantially the same as that on which, when rowing through a strong current, the nose of the boat must be pointed up-stream above the spot it is desired to reach. If light is brought to us in the form of ether waves, the phenomenon of aberration shows that the earth must be moving through a stagnant ether, so that to us on the earth there must appear to be a current of ether streaming past the earth. It is natural to attempt to measure the velocity of this stream, and so determine the earth's absolute velocity in space. In the famous Michelson-Morley experiment, which was designed to this end, a beam of light was split into two parts. One part is sent up the ether stream and comes down again to the starting point after reflection by a mirror, while the other half is sent an equal distance across stream, and again comes back after reflection. Thus the total length of path is the same in each case, and if the earth w^ere at rest in the ether, the time occupied in going and returning would be the same for each ray. But if there is a stream of ether moving past the earth, it is readily seen that the second half of the beam must gain in time on the first, for the time lost in moving against stream by the first ray is not fully compensated by the gain in time when moving with the stream. The experiment w^as arranged so that any difference in the time of the two rays would show itself in the formation of interference fringes, and this difference would give a measure of the earth's velocity through the ether. But the experi- ment, repeated with all possible checks and refinements, refused to disclose any motion of the earth through the ether at all, and other quite different experiments designed to the same end gave one and all precisely the same reply. Thus, assuming that light consisted of weaves in the ether, experi- ment and observation led to the conclusion that the ether must be at rest, and the earth at rest in the ether, so that the evidence seemed, if strictly interpreted, to lead back to the geocentric universe of pre-Copernican days. This was the cloud over the dynamical theory of light. From the attempts of Lorentz and Einstein to unravel this con- tradiction, the theory of relativity has arisen. It says in effect : "The existence of an ether is conjectural, while the results of the ]\Iichelson-Morley and other experiments are certain. Let us abandon the dynamical interpretation of light, which is based on the conjectural existence of an ether, and examine what laws are obtained by starting from the hypothesis that all attempts to measure the absoluie velocity of the earth, or of any other mass, must necessarily 1917] on Recent Developments of Molecular Physics 79 lead to a nul result." On this basis, supplemented by certain exten- sions and generalisations, it is found possible to construct a definite and consistent system of laws. They of course differ from the dynamical laws based upon the supposed existence of an ether, but they differ only where relative motion is involved, because the rela- tivity theory makes its laws agree with those of ordinary dynamics when there is no relative motion. Wherever the old and the new theories differ, an appeal to experiment has so far invariably decided in favour of the new theory of relativity. The most recent triumph of the new theory is of such great interest that it may perhaps be mentioned in some detail. Gravitation has always stood aloof from other physical phenomena. Since Xewton formulated the law of the inverse square of the dis- tance, nothing has been added to the law and nothing taken away. Except that it represents a natural weakening of gravitational effect by spreading out in space, no explanation of the law has ever been given, nor even a plausible conjecture as to the relation between gravitation and other physical agencies. Eecently Einstein has found that the Xewtonian law is inconsistent with the postulates of his general relativity theory. On amending the law so as to con- form to these postulates, it appears that the orbit of a planet about ■ the sun ought no longer to be a simple ellipse, as it was under the Newtonian law, but rather an ellipse slowly rotating in its own plane. For instance, the orbit of Mercury ought to revolve at a rate of al)out 42 • D" per century. Now, for some time one of the out- standing problems of astronomy has been the explanation of the irregularities in the orbit of Mercury. After allowing for all known causes of irregularity, there was found to be outstanding a secular advance of the perihelion, or more simply a slow rotation of the orbit, of amount almost exactly equal to the •42 '9'' per century predicted by the relativity theory of Einstein. To sum up, then, it is clear that the first of our two clouds has been dissipated by the theory of relativity. This is not surprising, for the theory was in effect designed for this special purpose. But it is important that the cloud has been removed without another one appearing to replace it. Indeed, other clouds have also been removed in the process, such as that surrounding the orbital motion of Mercury. The relativity theory has succeeded, as we have seen, by relegating the ether to a position of absolute unimportance. Whether the ether exists or not w^e do not and cannot know, but the relativity theory indicates that everthing happens exactly as if the ether did not exist. The new theory is concerned with the discovery and formulation of laws rather than with their causes, and so makes no claim to pronounce on the existence of an ether ; but it is clear from the experimental evidence of the Michelson-Morley experiment, that if it is finally necessary to call upon an ether to interpret phenomena, this ether will be something quite different 80 Mr. J. H. Jeans [March 30, from what we imagined it in the past. In the meantime, the attitude of the relativity theory to the ether is that it has no need for that hypothesis. The second cloud, over the dynamical theory of heat, is in effect the theorem of Equipartition of Energy, discovered as a mathematical theorem by Maxwell in 1857. The dynamical theory of heat asserts that heat is a mode of motion. Every body has a certain number of capacities of internal motion, or to use the technical term, degrees of freedom, the energy of motion of these degrees of freedom forming what we call the heat of the body. The theorem in question begins by assuming that the motion is determined by laws of the type of Newton's laws of motion, and on this hypothesis it shows that, when any temporary disturbances have passed away, the energy is, so to speak, fairly rationed out amongst the different degrees of freedom. It is not proved that one degree of freedom will have just one ration, but if we take any large group, no matter how selected, their average amount of energy will always be exactly one ration. We can state the matter in a different way l)y saying that the energy is distributed at random amongst the different degrees of freedom : none of them gets any preferential treatment. The simplest instance of the truth of the theorem is, perhaps, found in the law that the atomic heats of all elements is the same. On the average an atom of silver has just the same energy as an atom of aluminium at the same temperature. The atom of silver is four times as massive as the atom of aluminium, but the energies are made the same by the velocities in silver being just half of those in aluminium. Another aspect of the meaning of the theorem of equipartition deserves attention. A column of air, say an open organ-pipe of 16 ft. length, can sound not only its own note, but a number of harmonics as well — one in the first octave above the fundamental note, two in the octave above, four, eight, sixteen, and so on, in the succeeding octaves. The degrees of freedom of the air inside the pipe may be thought of as arising from the possibility of motion in spaca of the molecules of the gas, but they may alternatively be thought of as the possibility of the pipe sounding its fundamental note and all the harmonics, down to those of the very shortest wave-length, com- parable with the distances apart of the molecules in the gas. The principle of equipartition now requires that when any exciting agency has died away, and only pure heat-motion remains, the energy shall be distributed equally among all its notes. It can in point of fact be shown by mathematical demonstration that the random heat- motion of the molecules inside the pipe can be resolved into a system of wave-motions such that the fundamental note and all the harmonics have, on the average, exactly the same amount of energy. Thus, so long as the theorem of equipartition remains true, we may regard heat-motion as a musical effect, produced by sounding all the notes which the system is capable of sounding, with equal energy. 1917] on Recent Developments of Molecular Physics 81 A numljer of instances, such as that of the atomic heats of metals ah'eady referred to, j^rove that the theorem is true m nature, at least within certain limits. But the limits are easily discovered, and it is readily seen that the theorem is not of universal applica- bility. For example, in the instance just taken, the atom of silver has four times as many electrons in its structure as the atom of alumininm, so that its internal structure has four times as many degrees of freedom. AVhy, then, does it not get four times as much energy ? This and similar cases of failure of the theorem formed the cloud over the dynamical theory of heat. A good deal of information can be obtained by investigating in what ways the energy is distributed in the cases in which the theorem Silver Copper T =- 100 200 Aluminium Fig. 1. of equipartition is found to fail. In the case of sohd elements such as silver and aluminium, it is found that all the heat-energy resides in the motions of the atoms as a whole ; the internal motions of the electrons get none at all. The same is true in a monatomic gas, such as helium or mercnry vapour, as is shown by the fact that the ratio of specific heats is 1§. In a diatomic gas at ordinary tempera- tures, three-fifths of the total energy resides in the motion of translation of the molecules, while the whole of the remaining two- fifths resides either in the motion of rotation of the molecules or in YoL. XXII. (Xo. Ill) G 82 Mr. J. H. Jeans [March 30, the to-and-fro motion of the two atoms of which the molecule is formed, probably the latter. The instances so far mentioned are sharply divided into cases of complete success of the theorem and case of complete failure. But every scientific investigator will recognise that our chances of unravelling the causes of failure will be enormously improved if we can find a case of gradual transition from truth to failure. An interesting case of failure of exactly this kind has been disclosed by recent investigations on specific heats at low temperature. If the principle of equipartition held, even as regards the atomic motions in a solid, the atomic heats ought to be the same for all elements. They are so at high temperatures, but there is a steady falling off as the temperature decreases. The specific heats of silver, copper, and aluminium at low temperatures, as measured by Nernst and Lindemann, are shown in Fig. 1. I 2 Graph of Fig. 2. Debye, attacking the question mathematically, has shown that the observed values of the specific heats, both for these and other suljstances, are exactly what they would be if the energy were not rationed out equally amongst the different waves, as demanded by the principle of equipartition, but according to the law where x stands for hvjBT, v being the frequency of the vibration, T the absolute temperature, and li and h being constants. Fig. 3 shows the theoretical curve deduced by Debye from this law, together with the observed values of Nernst and Lindemann for three 1917] on Recent Developments of Molecular Physics elements, " sound ' energy We now see that in beat motion at low temperatures the " is one in which all harmonics do not sound with equal the higher harmonics get nothing, like the share of energy allotted to them by the theorem of equiparfcition, and the energy tends to concentrate in the vibrations of lowest frequency. The formula just given has the very special significance that it also expresses the partition of energy amongst the different vibrations in the s^^ectrum of a normal black body, as given by the well-known and now generally-accepted formula of Planck. Indeed, it is I'D -X y / / / / / } / / J r/0 = -l -2 -3 -4 -5 -6 -7 -8 -9 VO M 1-2 >-3 14 Fig. 3. Atomic Heats at Low Temperatures (+ Aluminium, o Copper, x Silver). probable that for dynamical reasons the partition of energy in the black body spectrum must form an indicator of the partition of energy in the black body itself, out of which the spectrum originates. Planck has proved that this is necessarily the case ; but his argument is weakened, and to some extent invalidated, by the circumstance that the proof is based on the Newtonian laws of motion which we are now discarding. In general, however, we may say that in every case examined the partition of energy in vibratory motions of all kinds must be supposed to be that given bv the above formula, When x is small^ a2 84 Mr. J. H. Jeans [March 80, covering the case of slow vibrations, the formula is of unit value, and the partition is one of equality ; on the other hand, the formula shows that vibrations of high frequency get no energy at all, so that here we get the extreme case of failure of the law of equipartition. It is extremely important for us that the theorem does fail in this way, because if all the heat energy in the Avorld were to distiibute itself equally over all the degrees of freedom in the world, as required by the theorem of equipartition of energy, everything would become frozen and dead within a small fraction of a second. Although the view has been opposed in the ])ast, there is now, I think, no room for doubt that the failure of the theorem of equipartition of energy must be interpreted in the most obvious and direct way. The theorem is true subject only to the assumption that the motion is governed by Newton's laws ; as a matter of experiment the theorem is found' not to be true of high-frequency viljrations ; therefore the motion of high-frequency vibrations is not governed by Newton's laws. We must search for a new system of dynamical laws which shall give the observed partition of energy. The formula xjie'' — 1), which is believed to give the true partition of energy, was originally deduced by Planck from theoretical considerations ; but the underlying conceptions were of such a strange and novel nature that at first they gained but little credence. But when the law of partition is known, it becomes merely a mathematical problem to discover what laws of motion will result in this law of partition. In 1911 I sliowed that this law of partition could only result from laws substantially identical with those already assumed by Planck. Shortly after, Poincare announced the same result, with the important addition that the main nature of the laws would not be altered by a slight variation in the observed law of partition. Planck had assumed that energy was transmitted not by continuous processes but by a system of jumps and jerks. It appears that the mere fact that the energy is not divided equally among the different vibrations is sufficient to show that there must be discontinuities of some kind in the fundamental laws of motion. The particular type of discon- tinuity which is found necessary to lead to the observed formula xjif — 1) is expressed by Planck's equation e= llv. Here li is the same constant as occurs in the value of a*, v is the frequency of the vibration in question, and e, equal to hv, is found to be of the same physical dimensions as energy, and may be spoken of as the "quantum" of energy associated with a vibration of frequency v. The law of discontinuity is such that the vibration can only gain or lose energy by whole quanta. Thus a vibration of frequency v may have no energy at all, or one quantum, or two quanta, but cannot for instance have half a quantum or \\ quanta — the energy changes by discontinuous jumps. 1917] on Recent Developments of Molecular Physics 85 It appears, then, that we are brought to the contemplation of a universe in which the ultimate motion is of a discontinuous nature. The supposed continuity of nature must be only an illusion ; motion when seen on a large scale is continuous, but is resolved into discon- tinuity when we imagine it viewed under a sufficiently high-powered microscope. Such revolutionary conceptions will be made mentally more palatable to us if we can find direct evidence of the " jumps " in question, and a good deal of such evidence exists. Perhaps the most striking, although not the most direct, evidence is provided by Bohr's theoiy of line-spectra. We know from the researches of Rutherford that the hydrogen atom consists of two constituents — a positive electron and a negative electron — circling round one another. Bohr assumes that only a limited number of orbits are possible ; the two electrons may circle at distances such that the motion possesses one, two, or any integral number of the quanta of energy corresponding to the frequency of rotation, but at no other distances. Sudden drops from one of these distances to another can take place, and when this happens the energy set free leaves the atom in the form of one quantum of monochromatic light, the frequencies of these bundles of light giving the line-spectrum. The line-spectrum has always defied interpretation in terms of the old mechanics ; indeed, the old mechanics made it impossible that a line-spectrum could occur at all. Bohr's theory has given a brilliant explanation ; his theory predicted the position of the lines exactly, and further predicted the existence of other lines in the infra-red which were not known to him when he published his theory, but were subsequently discovered by Lyman. The theory also predicted a large part of the helium spectrum, and a comparison of this spectrum with that of hydrogen enabled Fowler to determine the mass of the electron to an accuracy at least equal to that of the best of previous determinations. Einstein has supposed that when the quantum of energy is set free in the form of radiation from radiating matter it does not spread out in space, but remains as a compact bundle of energy. We must, on this view, think of radiation not as waves spreading out in a sea of ether, but perhaps rather as fishes swimming out into a sea of — we do not know what. If this is so, we might be able to obtain very direct evidence of the existence of these fishes by spreading nets to catch them. Suppor.e we spread nets of varying meshes, say two, four, six, eight inches, and set free what the quantum theory tells us ought to be five-inch fishes, and what the old mechanics tells us ought to be waves in our sea. Suppose, we find that the six-inch and eight-inch nets are unafi'ected, while the two and four-inch nets show holes in each case of five inches. Suppose further that millions of what the quantum theory pronounces to be one-inch fishes have no effect, while even the smallest number of what the quantum theory calls three and five-inch fishes are found to make holes of the corre- 86 Mr. J. H. Jeans [March 30, sponding size — shall we not be justified in supposing that we are not altogether on the wrong track in believing that the fishes really exist ? Allowing for the necessary imperfections of an analogy, evidence of the kind just described is provided by the photo-electric effect. High-frequency light falHng on a clean metallic surface breaks up the atoms of the metal, the breakage being shown by the liberation of electrons. The energy required to liberate an electron from an atom of any given metal is known from other sources — this corresponds to the mesh of the net ; in addition to this, the electron brings away with it a certain amount of kinetic energy. On adding this to the energy required to liberate the electron we invariably obtain one quantum of energy of the frequency of the incident light. If the light is of frequency such that one quantum is less than the energy required to liberate an electron we may allow the light to fall on the metallic surface for years, and no atoms are In-oken up, no matter how intense the light, while even the feeblest light, if of sufficiently high frequency, will at once start to liberate electrons. Such phenomena as the photo-electric effect and the line-spectra of the elements are quite inexplicable in terms of the old dynamics, while they receive such complete and convincing explanations in terms of the quantum-theory that we might be inclined to jump to the conclusion that the quantum-theory contained the whole truth and nothing but the truth. On the other hand, all interference- phenomena and phenomena of reflection, polarisation, etc., receive a simple explanation in terms of the old dynamics, and seem at present inexplicable in terms of the new. It seems impossible to reconcile the new quantum-theory with the old undulatory theory of light. There is a very real difficulty here ; indeed, it constitutes the big out- standing puzzle of present-day physics. The evidence of interference suggests that light must be continuous and almost infinitely divisible, while the evidence of the photo-electric effect is that light consists of discrete " quanta " which are discontinuous and completely in- divisible. No solution has yet been found ; one has hardly been suggested. It may perhaps be worthy of notice that the theory of relativity is also to some extent antagonistic to the undulatory theory of light, for when the medium through which the waves were supposed to be propagated is aljolished, the waves themselves reduce to little more than a mathematical fiction, and the undulatory theory of light reduces to the solution of a differential equation. In the past the waves in the ether have been regarded as the ultimate reality, while the differential equation has been regarded merely as a means of calculating the motion of the wave. Perhaps the scientist of the future will regard the differential equation as the ultimate reality, while the whole mechanism of the undulatory theory — ether, forces, waves, interference, etc. — will be regarded as an extraordinarily 1917] on Recent Developments of Molecular Physics 87 cumbersome nineteenth century model to represent the phenomena demanded by the differential equation ; the differential equation will be regarded as determining the changes of the inanimate parts of the universe except under certain conditions, which we speak of as the presence of matter, where the differential equation will yield to an equation of finite differences — the expression of the complete quantum- theory. These speculative reflections may indicate the direction in which a solution of the difficulty may perhaps ultimately be found, but they are very far from supplying this solution. [J. H. J.] GENERAL MOXTHLY MEETING, Monday, April 2, 1917. Charles Hawksley, Esq., Vice-President, in the Chair. Murray Stewart was elected a Member. The Secretary announced the decease of Professor Jean Gaston Darboux, Sc.D. "(Cantab), Hon. F.R.S. Hon. M.R.L, in February 1917 ; and the following Resolution passed hj the Managers at their greeting held this day, was read and unanimously adopted : — Resolved, That the Managers of the Eoyal Institution desire to record their sense of the loss sustained by the Institution, and the World of Science, by the decease of Professor Jean Gaston Darboux, Sc.D. (Cantab), Hon. F.R.S. Hon. ^M.R.I., Secretaire Perpetuel de I'Acadeniie des Sciences de Paris, Grand Oificier de la Legion d'Honneur, Palais de I'lnstitut, Paris. He was the author of the following treatises : — " Sur une Classe remarquable des Courbes et des Surfaces Algebriques " ; and " Theorie Generale des Surfaces." His originality and distinction was such that he was honoured by the majority of the great Universities and the principal Scientific Societies of the world. He was awarded the Sylvester ]\Iedal by the Royal Society in the year 1916. Resolved, That the Managers desire to express, on behalf of the Members of the Royal Institution, their most sincere sympathy with the family in theiK bereavement. 88 General Monthly Meeting [April 2, The Peesexts received since the last Meeting were laid on the table, and the thanks of the Members returned for the same, viz. : — FROM The Secretary of State for India — Memoirs of the Department of Agriculture : Botanical Series, Vol. YIII. ISTos. 5-6; Chemical Series, Vol. V. ISTo. 1. 8vo. 1916. Agricultural Journal, Vol. XII. Part 1. 8vo. 1917. Agricultural Research Institute, Pusa : Bulletin, Nos. 64-66. 8vo. 1916. Kcdaikanal Observatory, Bulletin, Nop. 53-54. 1916. Abbadia, Observaioire [The Director) — Proces Verbaux des Seances de I'Academie des Sciences depuis la fondation, Tome VI. 4to. 1915. Accadcmia dei Liiicei, Boma — Atti, Serie Quinta, Rendiconti : Classe de Scienze Fisiche, Mathematiche e Naturali, Vol. XXVI. 1^ Semestre, Fasc. 4-5. Svo. 1917. Accountants, Association of — Journal for Feb.-March 1917. Svo. A7nerican Chemical Society — Journal for March-April 1917. Svo. Journal of Industrial and Engineering Chemistry for March 1917. Svo. American Geographical Society — Geographical Review for March-April 1917. Svo. American Journal of Physiology — Vol. XLII. No. 4. Svo. 1917. Asiatic Society of Bengal — Journal and Proceedings, 1914-16. Svo. Asiatic Society, Boyal — Journal for April 1917. Svo. Astronomical Society, Boyal — Memoirs, Vol. LXI. 4to. 1917. Monthly Notices,' Vol. LXXVII. Nos. 3-4. Svo. 1917. Bankers, Institute o/~Journal, Vol. XXXVIII. Parts 3-4. Svo. 1917. Boston Public Library— Bulletin, Third Series, Vol. X. No. 1. Svo. 1917. British Architects, Boyal Institute of — Journal, Third Series, Vol. XXIV. Nos. 7-S. 4to. 1917. British Astronomical Association — Journal, Vol. XXVII. Nos. 4-5. Svo. 1917. California, University o/^Collected Reprints of the George William Hooper Foundation, Vol. I. Svo. 1915-16. Canada, Department of Marine — Report of the Meteorological Service for the Year 1914. Svc. 1917. Canada, Department of Mines — Geological Survey: Memoirs 89, 91, 92. Svo. 1916. Canada, Boyal Society o/— Transactions, Third Series, Vol. X. Dec. 1916. Svo. Carnegie Institution - Cor\ix\hMt\o-n.?i from Mount Wilson Solar Observatorv, Nos. 37-41, 43, 124-126. Svo. 1917. Annual Report of the Directors of the Mount Wilson Solar Observatorv. Svo. 1916. Chemical Industry, Society o/— Journal, Vol. XXXVI. Nos. 4-5, 7. Svo. 1917. Chemical Society — Journal for Feb.-April 1917. Chemistry, Institute o/— Proceedings, Part 2, 1917. Svo. Civil Engineers, Institution o/— Proceedings, Vol. CCII. Part 2, 1915-16. Svo. 1917. Consolo Enrico {Banca Commercialc Italiana) — The War in Italv. Vols. IV.-VI. 4to. 1916 Editors — American Journal of Science for March 1917. Svo. Athen.eum for Feb.-April 1917. 4to. Author for March-April 1917. Svo. Chemical News for ]March-April 1917. 4to. Chemist and Druggist for March-April 1917. Svo. Church Gazette for March-April 1917. Svo. Concrete for March-April 1917. Svo. Dyer and Calico Printer for March-April 1917. 4to. Electrical Engineering for March-April 1917. 4to. 1917] General Monthly Meeting 89 Editors— continued Electrical Industries for IMarch-April 1917. 4to. Electrical Review for March-April 1917. 4to. Electrical Times for March-April 1917. 4to. Electricity for ]March-April 1917. 8vo. Electric Vehicle for March 1917. 8vo. Engineer for ]March-April 1917. fol. Engineering for March-April 1917. fol. General Electric Review for March-April 1917. 8vo. Horological Journal for March-April 1917. Svo. II Nuovo Cimento for July-Aug. 1916. Svo. Illuminating Engineer for Feb.-March 1917. Svo. Journal of Physical Chemistry for Feb. 1917. Svo. Journal of the British Dental Association for March-April 1917. Svo. Junior Mechanics for ]\Iarch-April 1917. Svo. Law Journal for March -April 1917. Svo. 5[odel Engineer for March-April 1917. Svo. Musical Times for March-April 1917. Svo. Nature for March- April 1917. 4to. New Church Magazine for ^March-April 1917. Svo. Page's Weekly for March-April 1917. Svo. Physical Review for March 1917. Svo. Power for March-April 1917. Svo. Power User for March- April 1917. Svo. Science Abstracts for Feb.-March 1917. Svo. Tcheque, La Nation, for Feb.-March 1917. Svo. Terrestrial Magnetism for Dec. 1916. Svo. War and Peace for ]\Iarch-April 1917. Svo. Wireless World for March-April 1917. Svo. Zoophilist for March-April 1917. Svo. Franklin Institide— J onvnsil, Vol. CLXXXIII. No. 3. Svo. 1917. Frazer, Lady— The Gods in the Battle. By P. H. Loyson. Svo. 1917. Geiieral Electric Co., Ltd.— The War in Italy, Vols. I.-VI. 4to. 1916. Geographical Society, Eoyal — Journal, Vol. XLIX. Nos. 3-4. Svo. 1917. Geological Society of London — Abstracts of Proceedings, Nos. 1002-5. Svo. 1917. Imperial histitute—'^MWeiva, Oct.-Dec. 1916. Svo. L-on and Steel Institute — Journal, Vol. XCIV. Svo. 1916. Jugoslav Committee— ^a\xthey:i\ Slav Bulletin, Nos. 2S-9. 1917. Life-Boat Institution, Boyal National — Journal for Feb. 1917. Svo. London County Council — Gazette for March-April 1917. 4to. Madrid, Beale, Academia de Ciencias— Revista, Tomo XIV. No. 12 ; Tomo XV. Nos. 1-5. Svo. 1916. Anuario, 1917. 16mo. Mechanical Engineers, Institution of — Proceedings for 1916, Oct.-Dec. Svo. Meteorological O^ce— Monthly Weather Reports for Jan. -March 1917. 4to. Weekly Weather Reports for Feb. and April 1917. 4to. • Daily Readings for Dec. 1916 and Jan.-Feb. 1917. 4to. Geophysical Journal for May-June 1916. 4to. Meteorological Society, Boyal — List of FeUows, 1917. Svo. Montpellier Academie des Sciences — Bulletin, Jan. 1917, No. 1. Svo. New York, Society for Experimental Biology — Proceedings, Vol. XIV. No. 4. Svo. 1917. Statistics, 1915, Vol. III. 4to. 1916. Neiv Zealand, High Commissioner for — Patent Office Journal, March 1917. Svo. Paris, Academie des Sciences — Connotes Rendus. Tomes CLVIII.-CLIX. 4to. 1914. DO General Monthly Meeting [April 2, Paris, SocUte cV Encouragement pour l' Industrie Naiionale — Bulletin for Jan.-March 1917. 4to. Pharmaceutical Society of Great Britain — Journal for March-April 1917. 8vo. Pliotographic Society, i?oi/a?— Journal, Vol. LVII. Nos. 3-4. 8vo. 1917. Post Office Electrical Engineers, Institution o/— Journal, Vol. X. Part 1, April. 1917. Paper, No. 70. 8vo. 1917. 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Vice-President, in the Chair. Professor Pt. H. Biffen, M.A. F.R.S. The Future of Wheat Growing in England. [No Abstract.] 1917] The Organs of Hearing in Relation to War. 91 WEEKLY EYEXIXa MEETING, Friday, April 27, 1917. Sir James Crichtox-Browxe, J.P. M.D. LL.D. F.R.S., Treasurer and Vice-President, in the Chair. DuxDAS Grant, M.D. M.A. F.E.C.S. M.R.I. The Organs of Hearing in Relation to War. "While even a slio-ht duhiess of hearins; has an undoubted disturbinof effect in the simpler evolutions of a volunteer, the necessity for a reasonably good amount of hearing -power by the soldier under train- ing or in the field is unquestionable. Hearing for the whispered voice at fifteen feet with either ear may be accepted as a minimum standard. Under a voluntary system it has apparently been neces- sary to admit men whose hearing-power was considerably below this, but where universal service affords a supply of men greater than is required such a defect would justify refusal. Whether deafness of one ear renders a man unfit for service is a moot point, as one good ear is perhaps better than two poor ones. [The lecturer cited two cases of men with one-sided deafness who had proved very useful soldiers during the earlier years of the war. One had become a sergeant in a Highland regiment, the other was a driver in the Field Artillery. In neither was the one-sided deafness discovered until the other ear was temporarily deafened by shell- concussion.] A man with only one hearing-ear is not well fitted for the infantry, but may be quite useful in the artillery, transport or medical service. There is no doubt that our pension list will be enlarged by the inclusion of men who were passed into the army while already dull of hearing, or affected with diseases of the ear, and whose dulness or disease has been aggravated by military service. The advisability of being able to pick and choose is an argument for the institution of a reasonable measure of universal liability to military service. In the Air Service the supply has been greater than the demand, and the quality of the highest. Rigid tests of the hearing, vision and other functions are applied before candidates are admitted, and the brilliant results obtained have surpassed all expectation. To explain the various modes in which the organs of hearing may suffer in warfare, their structure and functions were shortly con- sidered in order, viz. the auditory cortical centres on the surface of the brain, the nerve tracts in the brain leading from the internal 92 Dr. Dundas Grant [April 27, ears to these cortical ceutres, the internal ear itself, and the tympanic mechanism by which the sonorous vibrations are received. A sensation of sound is appreciated by the brain, and the parts of the cortex allocated for this function have been specified by experi- ment and by observation of disease. By kind permission of Colonel Mott the lecturer was able to show on the screen the photograph of a brain in which the auditory cortical centres were destroyed by disease on the two sides successively. The case, briefly stated, was that of a woman in whom, owing to disease — blocking of certain arteries — the auditory centre of the left side was destroyed. The result was not loss of hearing but loss of the power of understanding words and of naming things. The corresponding area on the other side gradually took on these functions and she recovered the understanding for words ; she got married and the birth of her first child was unfortunately followed by a blocking of vessels on the right side ; the destruction of the two auditory centres led to complete deafness and she ultimately died. Colonel Mott was able to obtain possession of this instructive specimen, and his description of it is now a "classic" in neurology. Certain tracts of nervous tissues can be traced from the auditory nerve-endings in each internal ear running to both cortical centres. This is why destruction of one centre alone is not sufficient to cause deafness. The auditor'ij nerves themselves take their rise in certain sensory nerve-cells in the cochlea of the internal ear^ and these cells are bathed by a liquid which is set in motion by the stapes, the inner- most of the chain of bones attached to the tympanic membrane, whenever this membrane moves. The sensory nerve-cells are fur- nished with certain hairs which are disturbed or displaced by each vibration of the liquid (endolymph) in which they stand.* The auditory cells rest on a membrane made up of transverse fibres which are longest at the upper part of the cochlea and shortest at the base. Helmholtz taught that the fibres corresponded to particular tones, and that each entered into sympathetic vibration when the appropriate tone was sounded, very much as when we utter a sound in front of an open pianoforte with the dampers raised by the " loud " pedal. The organs of hearing are exposed to injury from various causes : — First, and very obviously, direct mechanical damage by bullets, fragments of shells or othe/ missiles actually striking the hearing passages, the middle or internal ear, or possibly the nervous strands connecting the internal ear with the brain. The active structures in * In a work recently published by Sir Thomas Wrightson since this lecture was delivered, the mode of this vibration is minutely studied, and his views receive confirmation from Prof. Arthur Keith's anatomical investigatioES. 1917] on The Organs of Hearing in Relation to War 93 the internal ear can be completely disorganised by a missile snch as a bullet passing through the head near the internal ear without actually touching it. This event is also observed in the retina of the eye. It is known as " commotion " or concussion, and when affecting the hearing produces what the French term " surdite a distcmce." [The damage to the structures of the internal ear by direct violence was illustrated by micro-photographs of sections made by Dr. J. Fraser, of Edinburgh. Kadiograms were thrown on the screen showing the appearance of a normal temporal bone, a temporal bone (petrous portion) rendered indistinct by the presence of the products of contusion and inflammation, and another with a fracture of the skull passing through the internal ear.] Second. — The force of the compression of the air., such as is induced by the explosion of a shell, frequently causes deafness by driving in the tympanic membrane and, with it, the small bones of the ear so as to induce a violent concussion of the internal ear. This appears to act most severely in those in whom there has been previous disease of the middle ear itself, or of the Eustachian tube and nasal passages. (Such diseases unless cured would exclude the candidate from the Flying Corps.) The explosion may at the same time rupture the tympanic membrane, and in this case some of its force is spent before it reaches the inner ear. It is found that cases of deafness due to concussion of the labyrinth are more likely to recover if there is concomitant rupture of the tympanic membrane. [The physical conditions accounting for this were illustrated by an experiment devised for the purpose. A light wooden hoop covered with a fairly resistant paper w^as hung by a hinge over the end of a drain-pipe. A revolver with blank cartridge was fired into the other end of the pipe and the concussion forced the hoop upwards on its hinge with great violence. The firm paper was replaced by a very thin one, and when the revolver was again discharged the paper gave way, W'hile the movement of the hoop was exceedingly slight.] Third. — The mere loudness of the noises^ either one definite exposure or a continuation of such, may produce deafness by over- stimulation of the auditory fibres (or nerve-centres). Castex has shown the damaging effect of continued exposure to the sound of gunfire on guinea-pigs. Yoshii, Siebenmann and Wittmaack have exposed guinea-pigs to continuous sounds of different pitch. Patches of degeneration of the auditory cells were found in the cochlea, nearer its apex in those exposed to low-pitched tones, and nearer the base in those exposed to the higher-pitched ones. [The lecturer expressed regret that we had to depend on foreign experimenters for such important investigations. With us research was very poorly paid, either in money or in social distinction, and the teacher or original investigator had usually to support himself by the practice of medicine. Furthermore, we were hampered by unreasonable restrictions in the pursuit of truth in physiology by experiments on lower animals. 94 Di\ Dundas Grant [April 27, desirable as it was that unnecessary pain should be avoided, and that unnecessary repetitions of experiments should be prevented. He recommended for support the society presided over by Lord Lamington, and expressed a hope that the State or the possessors of wealth would provide for the endowment of research.] Fourth. — The auditory centres may be thrown out of par by a nervous shock, the most typical of which is that of being " buried." Many who have undergone this terrifying experience have been deaf and voiceless when dug out. Slighter forms of fright produce this effect in more sensitive subjects. Such loss of hearing unconnected with physical damage to the auditory organs is termed ^'functional " decifness. The higher centres are, as it were, switched off, so that the sufferer is as unconscious of the sensations of sounds as if his internal ear-apparatus was destroyed. The internal ear and auditory nerves are, however, still in working order, and may be stimulated by sounds. This is shown by the occurrence of certain natural movements on exposure to sound even though the subject is quite unconscious of them. These movements are " reflex," and their occurrence indicates that the accompanying deafness is " functional " rather than physical or " organic." Kecovery is usual, and is sometimes quite dramatic in its suddenness, though when and how the recovery is to be brought about it is scarcely possible to predict. As a shock brings it on, sometimes another shock removes it. In one case a fall out of bed led to complete recovery from total deafness of this form. Fright can produce degenerative clianges in nerve-cells (disappearance of Nissl bodies, etc.), as shown in the special (Purkinje's) cells of the cerebellum in Crile's experiments on rabbits in relation to shock. There is also good reason to suppose that the dendrites of the neurons may retract as the result of shock and cause interruption of continuity in the nerve strands leading to the cortex of the brain. Colonel Mott favours the latter view, and in support of its feasibleness quotes Ross Harrison's observations on the growth of nerve processes from cells in the embryo. This deafness is analogous to that which may be induced by the so-called mesmerist or hypnotist by means of " suggestion," and is no doubt identical with deafness or other loss of sensation observed in true hysteria. The " conscious " is absent, but the " sub-conscious " is stiir more or less to the fore and open to impressions which the " conscious " would rule out or inhibit when not stupefied by fear or terror. Fifth. — Destruction of both auditory cortical centres as the result of wounds would produce deafness, but, of course, such an extensive injury could scarcely be compatible with life. Cases frequently occur in which more than one of these factors are present, and we may find associated with " functional " deaf- ness affecting both centres an organic damage to one of the labyrinths. Sixth. — Apart from injury, diseases of the ear are the cause of 1917] on The Organs of Hearing in Relation to War 1)5 many of the cases of war-deafness. Inflammatoiy conditions of the ear freqnentlj arise as the result of exposure to cold or damp or infectious disease of various kinds, including mumps and epidemic cerebro-spinal meningitis, popularly known as spotted fever. The latter is the cause of some of the most deplorable cases. The hearing-power in general is tested bv means of the voice, the watch, and numerous other sources of sound, but the extent of hearing for tones of various pitch is usually measured by means of tuning- forks. [The lecturer pointed to a fallacy in the use of tuning-forks, viz. that the hearing-power is usually calculated as in direct propor- tion to the length of time the tuning-fork is heard. In reality the tuning-fork dies away in proportion to the logarithm of the time, i.e. the Xaperian logarithm. The lecturer had dealt with this question in a paper read before the International Otolo2:ical Congress held at Boston, U.S.A., in 1913.] For the highest pitched tones the hearing was tested by means of Galton's Whistle, the steel wire or monochord, or small steel rods. Retention of hearing for these tones indicates integrity of the most vulnerable portion of the cochlea (i.e. the portion nearest the base, with the shortest fibres), and hence greater probability of recovery. The equilibrial jJortmi of the tahyrinth consists mainly of the semicircular canals forming the posterior half of that organ. [Their structure was shown by large diagrams and their small size by the actual human skull] They lie in three planes, so that they are displaced by movement of the head in any direction whatever. Inside their membranous lining there is a fluid which lags or continues in movement when the canal is moved or when it stops, thus disturbing the hairs on certain minute cells in the dilated portions of the tubes. These hair-bearing cells are connected by nerves with certain nuclei and with the cerebellum and spinal cord. They have also important communications with the nuclei of the nerves which control the movements of the eyeballs. The eyeballs enter into appropriate movements when the position of the head changes, and this is induced by the disturbance set up in the semicircular canals. If we rotate a person with normal semicircular canals the eyes make definite jerking movements, and if these movements do not take place we assume that the semicircular canals are damaged. If again we apply cold to the labyrinth, downward currents are produced and jerkings of the eyeballs follow. [The lecturer illustrated the effects of rotation by means of a circular trough filled with water in which stood some flexible reeds. He also explained the formation of downward con- vection currents in a large beaker of water, on the surface of which a lump of ice was placed. Upward currents were shown by means of a spirit-lamp below a beaker of water.] The " walking-stick " test introduced by Prof. Moure, of Bordeaux, is carried out as follows : The subject bends down, rests his forehead 96 Dr. Dundas Grant [April 27, on the top of a walking-stick and walks round the stick several times. He is then suddenly ordered to stand np and walk straight forward. If his labyrinths are normal he cannot do this, and he reels round to the side towards which he has been turning. [This was demonstrated by the lecturer.] If the labyrinths are destroyed, the subject walks straight forward in spite of the rotation. [A soldier whose labyrinths had both been destroyed by specific disease was shown and submitted to this test at the end of the lecture. He was seen to walk straight forward without difficulty.] The integrity of the equilibria! labyrinth can thus be tested by rotation or by syringing cold or hot water into the ear. The most convenient means is the blowing in of cold air by means of the lecturer's cold-air lahyrinth-testing apparatus, as used in the French army. These tests are important because they indicate the condition of the semicircular canals. If then along with deafness there is evidence of damage at the same time to the semicircular canals, the great probability is that the destruction of the internal ear has been very considerable, that the lesion is a severe one and unlikely to be followed by recovery. Simulation of deafness for the purpose of escaping dangerous duty or of securing compensation must be very tempting. It is not surprising that it should occur, but it is very surprising (and credit- able) that it should occur so seldom. There are tests by which it can generally be detected, but their consideration here would " not be in the public interest." The frequency with which deafness, either temporary or per- manent, arises in the course of active military service in the field can be only approximately surmised. In a number of our military hospitals about 1 • 4 per cent suffered from some form of deafness. In two German Army Corps 201o cases of disease or injury of the organs of hearing occurred in four months. It is to be remembered that many of the cases were those of ordinary inflammation of the middle ear, apart from injury, incidental to general disease or ex- posure to cold or wet, and that in many the ear-disease was existent, though perhaps quiescent, before enlistment. Professor Moure (Bordeaux) and Professor Lannois (Lyons) have given interesting statistics as to the nature of the disease or injury. The latter gives the results of his observations and treatment in 1000 cases under his care between March and December, 1015, as follows : — 1. Cases with existent ear-disease -, 323 (189 had suppuration, 134 had not.) 2. Cases without existing ear-disease G45 (262 simple concussion of labyrinth ; 383 concussion of labyrinth with rupture of membrane, in which 301 suppurated and 82 did not.) 3. Cases of deafness from " shell-shock " 32 19 17] on The Organs of Hearing in Relation to War 97 He found that in the absence of direct injury labyrinthine con- cussion was rarely followed by lasting deafness, and that deafness from concussion was much more frequent in those who had pre-existing ear-disease than in those whose ears were previously normal. The results of treatment were in proportion. Of those vrith previous disease 50 per cent were able to return to full duty, while of those with previously healthy ears all but 5 per cent recovered in whom the drum was not ruptured, while all recovered in whom the drum had given way. Early and appropriate treatment is obviously of the greatest importance both from the physical and the moral points of view. The prevention of war -deafness is a question associated with that of ear-protectors. These were dispensed with as a rule, or after use were usually discontinued. A number of officers have, however, borne testimony to the effectiveness of the Mallock-Armstrong protector in deadening the effect of explosions, while permitting of the hearing of orders. Lake, Jenkins, and others have devised ingenious plugs for the ears, and of course cotton-wool and plasticine have also found favour. The objection to many of these is the risk of their being driven in. Cases have occurred in which a plug of ear-wax in the ear has appeared to have protected the internal ear from damage by explosion, although of course the driving in of the plug of wax has caused temporary complete deafness, hearing being restored on removal of the wax. Habituation to the noise was usually established after a time, the subjects apparently acquiring a power of discrimination and of attending to or disregarding noises. An officer stated that during the continual rumbling din of a bom- bardment the report of a heavy gun close at hand was scarcely observed, while away from such bombardment the firing of a single small gun was startling enough to make the hearer jump. [The lecturer demonstrated this by having a rumbling roll on two kettle- drums played crescendo. Loud bangs on a big drum given at irregular intervals were scarcely perceived as anything more than a dull thud. When the kettledrums were silenced the bangs on the big drum were almost ear-splitting.] The after-condition of the deaf soldier depended on the degree of his deafness. If moderate it might not prevent the continuance of occupation in many trades or businesses, though in others it might be absolutely prohibitive. In very many it was a more serious handicap, such as thebusinessof barristers, salesmen, canvassers, booking-clerks, and in general any business caUing for rapid oral communication or comprehension of orders or instructions. A deaf writer has expressed the opinion that the dull of hearing are apt to forget the amount of trouble their affliction causes to other people. Hence employers are chary of employing them, not so much on account of their deafness as of the favours and privileges they YoL. XXII. (Xo. Ill) H 1)8 Dr. DiiiuIms Gr;ml I April ii7, (Iciiiiiiui. Ill |Jh!Iii cnrly :i|>|.r(»|)ii;il.(; l,iv;il,iiiciil. waH (!HH(;iili:il niifl nl'tcii IxMirlicinl. Kor I, he, cxI.niiiK!!)' (Iciif, iiHKiicli, iiiuiiy (MU'iipal.ioiiH wen; coiiiiilcLcly l»!irrc(I, bill/ " li|)-n!i'i,(liiiLC " oflcii ciuik! I-o iJicir JiHHiHUi.ncc!, uiid iii Hiiil,!ilil«'. ciiHcH iilmosi- 111)1(1(1 up Tor Um of Iiciiriiij^^ I(- is to !••• ic iiiciiilic.rc.d l,lin.(< nltsoliitc (IcjifiicsH in Homctiim'H |)iir('ly fiinotionnl mikI (»prii lu |,h(< p()HHil>ilil,y of (;oiiipl(!l,(; r(;<;ovcry. .\\\\n\\'^ l\u' (irrn./i(t/f(ifis U)\\f)\\(\i\ l»y jiriiiiiJ (l(!ji,r-iiiiil,('K liiivc, Ix-cn IK. led |)(M)t-, hIkmi- 11.11(1 (•lo;^^-!lUll(illf.,^ liiboiirin^^ (of vnrioiiH kinds), lll,ilo^ill^^ iiMiLnJ luid llltV'JliM('--\vo^lp(' foi* i,\\v. Hiinply dcid' if ^'\\v\\ l\\v oppoiimiily for Lriiiiiiii.u'. TIk! huwhimj (if '' li/)-rri/ilin(/" In drafriird iiicii iM (|iiilr dilVcrciil from l,('iic.liiri^^ Hpcccli Mild lip !(!Mliii<,^ to dciif iiiiitcK wlio liavi; no Itiisid kiio\vl(M|n(! oi' spcccli. In \hvnv. I, lie lip-pictiiniH corrcHpoiidiiis^ to tlu! <'l(i!iHilil.iiry hoiiikIh of wliicdi H\)Vor.\\ aiv made lip lniA'(! to Ik! lahorioiisiy prcHcMitcd,' vvIkw'chh for tliu deafened man a, more syiitliotic iiietliod is pnictiHiMJ, tluit JH, exonnHiii^r jiim in iJie ree(>i;iiition of wordn, plinises iiiid Heiiteii('(!H, rather than simple soniids, l»y the movements of the li|tM and faee. 'I'lie time re(piired (hipeiids on iJie capacity of tlie indfvidiial, ^^(»od 8i,i!;iit and general alertness lieini!; important fartorH. Sometimes the more hi<::ldyHMliicate(l snl»jecl,s have ^n-eiiier dillicnlty than tlii! less ciiltivuted in ac(piiriii,L;' iJie kna.ck of rapidly ,<;raspiii,<;" I he speaker's meaning. It miiHt of coiirse be recollected that the liia.riied man has a much larger arciimiilation of words and ideas amoiii;- which to pick out l,hoMe intended by the sjteaker, a,iid he has, therefon;, more hesita- tion in committing!: himself. In three months a, fair |)rolicieiicy is oxpected and very fre(pi(>ntly ailaii-ed. (lennaii authorities allow live or six montliH. The rnmch setun lo acipiire the art with <;reat facilil,y, and the i'^roiK^h mode of utterance is jirobaldy more favonrable lor li|') readint:: tlnin the l<]iis;lish or (Jerinan. It lias been Hiii^^^-csted that in view of the obvious limitations of liji-n^adiiii;, d(-a,f men nii<;hl, be tan, i^d it //////^/--.sv^r ///////. This would, of course, put (he deaf man in communication only with the coin- jtjiratively few peo|)Ie who speak on their linii:ers, and witii (hem he would b(> well enoiif^di olT with a pencil and writini^^-tablet. It would not |mt him in huich with the world at larire, or even enable him to read the word "Daddy'' on his little child"s lips. Lip-reading,' r(>-opens Ihe world to the deafened .man in a way only surpassed by restoration of hearinu power, which should, of course, receive Ihe first <'onsidera(ioii. (\)m]iensalion in the form of /icnsioiis or t/r(f(nifii's to (hose deafened throuuh mililary Hervico sliould be in proportion lo I lie decree lo which (he subject's earniuLC-powiM' is diminished, and this is 1017] on The Organs of Hearing in Relation to War 09 calculated mainly on the degree of deafness. Complete deafness ranks as the equivalent of the loss of one limb for pensioning purposes. In our warrant it counts as To per cent of complete disablement, and carries a minimum pension of nineteen shillings and sixpence a week. The assessment of the degree of dulness of hearing calls for tact, judgment and sometimes ingenuity on the part of the examiner. Although the case of the deaf man is not so hard from the wage- earning point of view as that of the blind one, it has some peculiarly pifiahle aspects, and is often characterised by a degree of moroseness, suspicion and depression from which the sightless soldier is singularly free. Those who may understand his difficulties and needs, and who may be in a position to help in removing them, would be doing a truly humane act by taking up his case. Postscript. — The lecturer has (since the delivery of this lecture) had the opportunity, of visiting various lip-reading classes for soldiers in France, and of reporting on them. As President of the Special Aural Board under the ]\Iinistry of Pensions, he has taken a share in the establishment of lip-reading classes in London and the various " pension areas" throughout the kingdom. (The earliest established class was, however, the one conducted in Edinburgh by Miss Stormonth.) The headquarters in London are located at 28 Park Crescent, where lip-reading classes are carried on daily, while recreation and refreshment are also provided. In this way the fatigue incident to the strain of attention during the class-hours is neutralised to the utmost possible extent. Reports on the subject are found in " Ptecalled to Life," No. o, and in the Reports on the Inter- Allied Conference on the "Treatment and Training of the Disabled," London, 1918. [D. G.] ANXUAL MEETING, Tuesday, May 1, 1017. The Duke of Northumberland, K.G. P.C. D.C.L. LL.D. F.R.S., President, in the Chair. The Annual Report of the Committee of Visitors for the year 1916, testifying to the continued prosperity and efficient management of the Institution, was read and adopted. Thirty-three new Meml)ers were elected in 1916. Sixty-two Lectures and Nineteen Evening Discourses were delivered in 1016. H 2 100 Annual Meeting [May 1, The Books and Pamphlets presented in 1916 amounted to about 316 vohimes, making, with 540 vokimes (induding Periodicals bound) purchased by the Managers, a total of 856 volumes added to the Library in the year. Thanks were voted to the President, Treasurer, and the Secretary, to the Committees of Managers and Visitors, and to the Professors, for their valuable services to the Institution during the past year. The following Gentlemen were unanimously elected as Officers for the ensuing year : President— The Duke of Northumberland, K.G. P.O. D.C.L. LL.D. F.E.S. Treasurer — Sir James Crichton-Browne, M.D. LL.D. D.Sc. F.K.S. Secretary— Colonel E. H. Hills, C.M.G. K.E. D.Sc. F.E.S. Managers. Henry E. Armstrong, LL.D. F.RS. Sir William Phipson Beale, Bart., K.C. M.P. Charles Vernon Boys, F.K.S. A.R.S.M. J. H. Balfour Browne, K.C. LL.D. John Y. Buchanan, M.A. F.E.S. W. A. B. Burdett-Coutts, M.P. I\I.A. Sir James Mackenzie Davidson, M.B.C.M. Donald W. C. Hood, C.V.O. M.D. F.R.C.P. The Rt. Hon. Viscount Iveagh, K.P. G.G.V.O. LL.D. F.E.S. Sir Charles Nicholson, Bart., M.P. M.A, LL.B. The Hon. Richard Clere Parsons, M.A. M.Inst.C.E. Sir James Eeid, Bart., G.C.V.O. K.C.B. M.D. LL.D. Alexander Siemens, M.Inst.C.E. M.LE.E. Samuel West, M.D. M.A. F.E.C.P. The Et. Hoj. Lord Wrenbury, P.C. M.A. Visitors. Ernest Clarke, M.D. B.S. F.E.C.S. John F. Deacon, M.A. Edward Dent, M.A. Lieut.-Colonel Henry E. Gaulter, F.E.G.S. W. B. Gibbs,F.E.A.S. James Dundas Grant, M.D. M.A. F.E.C.S. W. A. T. HaUowes, M.A. Henry E. Jones, M.Inst.C.E. M.LMech.E. H. E. Kempe, M.Inst.C.E. Francis Legge, F.S.A. James Love, F.E.A.S. F.G.S. Eichard Pearce, F.G.S. Sir Alexander Pedler, CLE. F.E.S. Hugh Munro Eoss, B.A. Joseph Shaw, K.C. 1917] Some Guarantees of Liberty 101 WEEKLY EYEXINCI MEETING, Friday, May 4, 1017. Sir James Reid, Bart., G.C.V.O. K.C.B. M.D. LL.D., Vice-President, in the Chair. H. WiCKHAM Steed, Author of " L'Angleterre et la Guerre." Some Guarantees of Liberty. It is rather more than three years since I had the honour, at the end of January, 1914, to address you upon " The Foundations of Diplomacy." At the beginning of that discourse I gave, as an explanation of its genesis, the gist of some correspondence Avhich had passed betAveen me at Vienna and an influential Englishman in London in the autumn of 1912, in which I had insisted that com- plications between Austria and Serbia might entail a European €onflagration, and compel Great Britain to fight at a moment's notice for the defence of the Scheldt and even of Calais, that is to say, of the " Narrow Seas," against a German army. In addressing you, I deplored the ignorance in which our people had been left as to the essential conditions of our national freedom, and asked, "Why should the British Government be deprived of the strength that comes from the support of an awakened and well-informed public opinion ? Why should our diplomatic action be hampered by the inability of our people to understand the bearings of issues that may drag us, willy-nilly, into a life-and-death struggle, whereas appreciation of the dangers involved might have enabled us to exercise our influence discerningly, and in time ? " I defined the true basis of diplomacy as " living knowledge in the service of an ideal," and said that, " if a nation is to play the part of a living, driving force in the world, it must have a conscious ideal. This ideal must be so plain and clear, so evidently con- nected - with the higher interests of the community, that it shall commend itself to and command the instantaneous support of the majority of right-feeling citizens." In conclusion, I declared it to be my profound " conviction that no shrewd calculation of interests, no canny avoidance of moral responsibilities, avails to replace a sane ideal in the management of foreign affairs ; and that if our nation is to come safely through the trials that may be in store for it, our people must again be taught a sound ideal — not, indeed, an ideal divorced from reason, but such as to inspire it and those who control 102 • Mr. H. Wickham Steed [May 4, its affairs with the belief that the thing chieflj needful is to know what is just and right, and to be ready and able to do it because "it is just and right." President AVilson has recently packed the whole of my contention into five pregnant words : " Right is better than peace." Neither I, nor any man, save possibly a small group of German soldiers, statesmen and bankers, could know in January, 1914, that in six months' time the Great AVar would be upon us. But those who,, like me, had lived for more than twenty-one years the political life of great continental States, felt that matters were slowly coming to a head, and that, in view of the deliberate purpose of Germany to secure the mastery of Europe and of the world, the date of the inevitable conflict would depend upon the readiness of liberty-loving States to defend their freedom against pretentions that she was certain to put forward at what might seem to her the most pro- pitious moment. My desire was to insist upon the need for public knowledge of the danger to which our liberties were exposed, and to make it clear that it is as " worth while " to fight in defence of our ideals as it is to concentrate diplomatic or national endeavour upon the " practical " objects of securing wealth and promoting trade. I added that " the doctrines known as ' pacifism,' and all cognate apologies for national unreadiness based upon faith in the pure intentions of others, are, I believe, the surest pledge of disaster." and that " the problem we have to consider is what constitutes in the modern world, effective force — to Avhat extent physical power is valueless without the co-efficient of moral strength used in the light of knowledge." The lessons of the war have to some extent given us the answer to that problem. The war has shown that, given equality of arma- ment, it is still moral strength that prevails — nay, that on occasion moral strength may more than counterbalance superiority of hostile armament. We have seen that if the Allied Powers can now hope to prevail against the iniquitous force of the enemy, it is because the moral quality of their cause will have enabled them to bring to bear still greater force in the service of right and in the defence of human freedom. What, however, do we mean by " freedom " ? Before we can hope to safeguard it we must know what it is we wish to safeguard. For our present purpose the idea of freedom falls practically into two categories — the freedom of the individual in the community and the freedom of the community itself. These are inter-related and inter-dependent. With the kind of freedom which an isolated individual might possess in an otherwise uninhabited island we have no concern. To him, his every whim Avould be law, his only care the thought of his own preservation. He would l)e non-political and non-moral because divorced from and outside any community. The freedom we have to consider is therefore the freedom of the 1917] on Some Guarantees of Liberty . lOS individual in the community, together with his preservation as an efficient unit in the community, and the preservation of the freedom and independence of the community as an efficient unit in the society of free nations. The war has rendered us no greater service than that of remind- ing us that individual freedom is contingent upon the preservation of the independence of the community. It has taught us that individual liberties preserved or acquired during centuries of political struggle mast be surrendered when the life of the community is at stake. Save among small minorities of extreme pacifists and " con- scientious objectors," this truth is to-day unchallenged. It is, moreover, sound liberal doctrine. John Stuart Mill recognized it in the Introduction to his essay on " Liberty," " There are also," he wrote, " many positive acts for the benefit of others which he (the individual) may rightfully be compelled to perform ; such as to give evidence in a court of justice ; to bear his fair share in the common defence, or in any other joint work necessary to the interest of the society of which he enjoys the protection ; and to peform certain acts of individual beneficence, such as saving a fellow-creature's life, or interposing to protect the defenceless against ill-usage, things which, whenever it is obviously a man's duty to do, he may right- fully be made responsible to society for not doing. A person may cause evil to others not only by his actions but by his inaction, and in either case he is justly accountable to them for the injury. The latter case, it is true, requires a much more cautious exercise of compulsion than the former. To make anyone answerable for not preventing evil is, comparatively speaking, the exception. Yet there are many cases clear enough and grave enough to justify that exception." This doctrine Mill held to be entirely compatible with the maintenance of " absolute freedom of opinion and sentiment on all subjects, practical or speculative, scientific, moral or theological." War for the defence of the community, or preparation for the eventual defence of the community, are certainly contingencies " clear enough and grave enough " to justify compulsion ; and the application of compulsion cannot in these cases be held an infraction of the rightful freedom of the individual. The fundamental characteristic of a liberal conception of freedom is that it regards compulsory interference with the life and conduct of individuals as the exception, not as the rule ; and looks upon them rather as necessary qualifications of a general principle than as ends in themselves. Since the applications of compulsion and the restrictions of individual liberty have to be carried out by the representative organs of the community — that is to say, by the State — it is evident that the liberal conception of freedom implies a liberal conception of the nature and of the functions of the State itself. 104 Mr. H. Wickham Steed [May 4, Here we come to the root of the difference between the British, or rather the Anglo-Saxon, and the German conceptions of individual freedom. This difference has sometimes been indicated by the saying that, in Anglo-Saxon communities, everything is permitted that is not expressly forbidden ; whereas in Germany, everything is forbidden that is not expressly permitted. Fears have been ex- pressed lest the growing organization and militarization of the community under stress of war, end by imposing upon us the very evil of Prussian militarism which we and our Allies are pledged to destroy. It cannot be gainsaid that there is some danger that extreme organization for purposes of dtfence may tend to crystallize the wholesome fluidity of our ideas and institutions, and to leave the body-politic afflicted hj arterio-sclerosis. It is not that we are ever likely to contract the Prussian fc)rm of the militarist disease, but, unless we are careful, we may develop a malady of our own of which the effects would be singularly pernicious. Thoughtful French writers have defined this war as a conflict between irreconcilable sets of ideas. It certainly reveals, if it is not the direct outcome of, a fundamental difference between Central and Western European con- ceptions of the State and its functions. What may be called the liberal Anglo-Saxon view of the State is that, in normal times, its functions should be limited to a minimum indispensable to the conduct of public affairs, and that it should interfere with the life and liberties of individuals only in so far as such interference may be required in the interests of the community as a whole. Govern- ment is thus regarded as a necessity imposed by the exigencies of public order and national defence, not as an end in itself. The Government, which is the active expression of the State, therefore stands as the servant of the community, and the servants of the State are, in theory if not always in practice, the servants of the community. The German, or at least the Prussian, theory is, on the contrary, that the State is something apart from and higher than the community. The members of the community are the servants of the State. It follows that the officers of the State are not only in practice but in theory the masters of the community, possessing attributes superior to those of the private citizen because they are derived from the State, of which the head is a Monarch governing by divine right and therefore answerable in the last resort to the Creator alone. The pohtical philosophy of Germany, especially since Hegel, teems with mystical glorifications of the State. Treitschke positively deifies the State. In his Politik he refers to "the objec- tively-revealed Will of God as unfolded in the life of the State " ; and calls the State " the most supremely real person, in the literal sense of the word, that exists." And again, " the State is the highest conmiunity existing in exterior human life, and therefore the duty of self-effacement cannot apply to it. As nothing in the world's his()Ory is its superior, the Christian obligation of sacrifice 1917] on Some Guarantees of Liberty 105 for a higher object is not imposed (upon it)." In the course of our history we, too, have known and resisted, not without success, the doctrines of divine right and the tyranny of Kings and State officials claiming to possess a semi-transcendental authority deriving from their position as delegates of royalty ; but we have fortunately never had a Hegel or a Treitschke to frame for the British State a pseudo- scientific character of absolutism. In any case our national sense of humour would probably have saved us from taking seriously the pretentious phrase-making of a philosopher like Hegel, which the keen critical sense of Schopenhauer, in his Kritik der Kantischen Philosophies castigated as follows : — " The greatest impudence in dishing up pure nonsense, in pasting together wild and senseless tissues of words, such as have hitherto been found only in lunatic asylums, appeared in Hegel and became the instrument of the grossest general mystification ever seen^with a success that will seem fabulous to posterity and will remain a monument of German foolishness." Xevertheless we have not entirely escaped the con- tagion of Hegel's " German foolishness." Some of our writers and political thinkers have mistaken it for transcendental wisdom. The effects of their advocacy of German ideas are clearly to be discerned. AVe need therefore to be on our guard lest we go astray when we presently find ourselves confronted by unforeseen consequences of the great sacrifices of individual liberty which we have made — and rightly made — during the war in the cause of national self- preservation. These sacrifices have been prompted by the sound and healthy instinct that recognizes the sense of responsibility towards the com- munity 0' the part of the individual to be an indispensaljle corollary ■of individual freedom in the community. This sense of responsi- bility is the very basis of freedom. All changes in State reorganiza- tion that tend to shift responsibility from the individual on to the State and to make individuals feel that others are watching over and for them, need to be accompanied by a corresponding increase in the moral and political virility of the individual. Otherwise the weaken- ing of his sense of personal responsibility would tend to diminish the security of the community as a whole. There is some analogy between the true doctrine of individual freedom in a free community and that of the Roman Church in regard to the "rights " of its members. Some twenty years ago an enterprising Roman prelate sought to prove that the doctrine of his Church was entirely compatible with the passage in the American Con- stitution which declares every man to have a natural right to " life, liberty and the pursuit of happiness." He was presently admonished by the ecclesiastical authorities and instructed that the only "rights" possessed by Christians are contingent upon the performance of their duty — the duty of saving their souls. Though the doctrine of civil liberty in an organized community cannot be thus dogmatically 106 Mr. H. Wickham Steed [May 4,, stated, and though the work of a free community is to ensure, in normal times, a maximum of ordered freedom to its members, it is clear that, at moments of crisis and common danger, questions of individual freedom lose significance in comparison with the para- mount necessity of preserving the community itself. The real problem to be solved is how to ensure a maximum of individual freedom in normal times with such efficiency of cohesion and spon- tan«ity of discipline in times of stress, as to safeguard the community against attack from outside or unwholesome tendencies within. In this sen^e it may be said that, according to sound liberal doctrine, the individual citizen has a right to liberty within the community not in order that he may follow his own will in every act of his life, but in order that he may use his liberty for the service of the com- munity. He is entitled to liberty because he cannot make his full contribution to the life of the community if he be the servant of the will of others, and if he be not able to bring to the common stock the fruit of his own activity and of his own judgment. Analogies between the structure of living organisms and that of organized communities have become hackneyed and are often misleading, but it remains true that, just as the health of living tissue depends upon the health and vigour of each individual cell, so the health and power of resistance of a community may depend upon the self-reliant vigour of each of its members. How far did the social and political conditions prevailing in Great Britain before the war fulfil the requirements of a free and healthy community ? To what extent were the " free institutions," of which we had been taught to be proud, discharging their func- tions? I cannot presume to claim infallibility for my personal impressions, though I had been accustomed for many years to observe the conditions of foreign communities and had long watched the course of affairs in England with a fresh and impartial eye. The impression made upon me by England in the years before the war was that of a community in rapid process of political and social degeneration. Our "free institutions," built up by centuries of struggle against autocratic tendencies, seemed to have fallen into the hands of a practically irresponsible oligarchy. I am not referring to any men or party in particular, but to a phenomenon. I have never belonged to any party. My ol)servations date at least from the Ijeginning of the century. In theory, the people controlled the working of the State through their n^presentatives in Parliament, a majority of whom, in their turn, delegated executive functions to a small body of Ministers. These controlled, ostensibly, the workings of departments over which they presided, and were jointly responsible to Parliament for the good government of the country. In reality, party organizations, supported by contributions from interested individuals or groups of individuals, foisted upon the people, by means of elaborate propagandist machinery, notions which 1917] on Some Guarantees of Liberty 107 it was ill the interest of the party that the people should accept. Every art of presentation and misrepresentation was employed to prevent the people from forming an impartial opinion. When, in these circumstances, popular representatives had been chosen, often with the help of party funds, those representatives became the slaves of the party machine, were compelled by all kinds of pressure to forego freedom of judgment, and to vote as the party managers might require. If the heads of the party happened to be in office, they were concerned far more with keeping themselves in office than with their guardianship of the welfare of the community. No means existed of bringing them rapidly to book for mistakes or misdeeds. It became a party interest to repel any attack upon them, and they could always be sure of a packed party majority in a machine-made Parliament. Within the departments over which they presided they were in appearance supreme, but in practice their ignorance placed them at the mercy of their technical advisers, the permanent officials, who were irresponsible save to them. Upon the errors of permanent officials there was little or no check. Public criticism or attack upon those officials was resented as "bad form" since they were unable publicly to defend themselves. If attack were made upor^ their responsible parliamentary chiefs, the packed parliamentary majority held those chiefs harmless. Between the various depart- ments of State there was little cohesion. England seemed to be governed by a disjointed series of administrative despotisms. Upon this system of concatenated political and economic interests, there was but one effective check — the power of publicity exercised mainly through the Press. But the bulk of the Press was also attached by a hundred ties to the party system. Newspapers appeared, more- over, more eager to maintain their circulations by tickling the ear of the public and by giving the public " what it wanted," than to court unpopularity by admonishing and educating the people. There were exceptions, but they were few. Then came the war. The full story of the critical days that preceded the entry of Great Britain and of the British Dominions into the war cannot yet be publicly told. In consequence of our shortcomings, of our guilt in leaving the people uninstructed as to the fundamental conditions of the freedom — nay, of the very existence of the community — we found ourselves, blindfolded, on the verge of the abyss. We escaped by a miracle — a miracle not entirely of our own working. But we resolved to do our duty, come what mighty and entered with stout hearts and ignorant minds upon the greatest revolution in our history. We now know how far that revolution has hitherto brought us. We do not know how far it may still carry us. We know only that there can be no turning-back, and that we must press forward to the bitter, or, as we firmly believe, to the triumphant, end. But the end will leave us with many new problems to face, and many an 108 Mr. H. Wickham Steed [May 4, unsuspected danger to our individual and national freedom. I do not refer to the adjustments that may be requisite in our system of national defence ; those adjustments may be constitutional, military, naval, economic and financial. The development of the submarine and airplane ; our realization of the fact that, though linked more firmly with the Oversea Dominions and, happily, in closer agreement with the United States of America, these Islands will henceforth be more than ever a part of the continent of Europe ; the need for maintaining firm political and economic alliances ; the recognition of the insidious character of cosmopolitan finance, and of the truth that a nation's wealth forms an integral part of its defensive resources — all these things may work radical changes in the forms of our provision for national security. But these things are, so to speak, externals. I have no fear of what is called "militarism." Militarism is, in the last resort, a psychological product, and our minds are not " made that way." But we are threatened by a far more serious danger — the danger of an overgrown, over-organized and consciously over-weening officialdom which, in the form of an immense bureaucracy, may strangle our ancient liberties with red- tape. Before returning to England I wrote a book upon the Hapsburg Monarchy, in which some hard, though I believe tnie, things were said of the Austrian official class or bureaucracy. Had I then possessed as much knowledge as I have since obtained of the ways of British officialdom, some, though by no means all, of the criti- cism of the Austrian official world would have been qualified by an indication that in England things were not very different. Even before the war the problem of the bureaucracy was fast becoming a nightmare in Austria. More than 'J00,000 individuals out of a total population of some oO,000,000 were in the direct employ of the State, and were entitled to regard themselves as masters of the public. Their division into eleven ranks or classes, each with its special emoluments and privileges, had given to the Austrian State and to Austrian society a semi-Chinese character and an Asiatic inelasticity. I doubt whether, even in Prussia or in Russia, the bureaucratic problem can be so profitably studied as in Austria. Its study forced upon me the conclusion that in no community where officialdom predominates and feels that it is " the Government," can there be any effective safeguard of individual freedom. One of the most characteristic illustrations of Austrian red tape was related to me by Count Clary und Aldringen, a former Austrian Premier. During his premiership a greengrocer in one of the Vienna thoroughfares Ijegan to sell dried vegetables. A grocer, who also sold dried vegetables and whose shop was in the same street, laid an information against him for violating the Gewerheordnunfj, or in- dustrial regulations. The police appointed a commission of inquiry, which decided, as a legal question was involved, to refer the matter 1917J on Some Guarantees of Liberty 109 to the Captaincy of the District. The Captain of the District appointed a commission of legal experts, who debated the question at great length and reported that the legal principle was so important that they were incompetent to give a decision. They therefore referred it to the Lord Lieutenancy of Lower Austria, an adminis- trative department which employs several hundred legal experts. The Lord Lieutenant appointed a special commission of lawyers in his turn. They debated the question in its length and breadth for several weeks, and finally agreed that the legal issue was so grave that it must be decided by the Presidency of the Council of Ministers. The President of the Council, Count Clary, appointed yet another commission of legal experts, whose chairman eventually reported as follows to the assembled Cabinet : — " The legal principle involved is so serious that your Commission is unable to agree in regard to it. Arguments of equal weight may be adduced in support of either view. In doubt as to the right decision, I ventured to consult my wife, who said, ' Dry or fresh, vegetables are vegetables.' In this sense I beg to report to your Excellencies." This view was accepted by the Cabinet, and the greengrocer, after eight months' suspension, was allowed to sell dried vegetables ! One point upon which 1 cannot venture to express a definite opinion is whether the officials who man our departments of State in England yet feel that they are " the Government," or aspire deliberately and wittingly to manage public affairs according to their own ideas or interests. I do not know — notwithstanding some alarm- ing symptoms — whether our officials, as a body, have yet acquired a corporate consciousness, whether they regard themselves as forming a State within the State, and as having a vested right in the manage- ment of pubhc affairs. On the whole, I doubt whether tbey have yet reached this stage ; whether the cumbrous practices which we call red-tape are more than an inherited routine developed by dislike of individual responsibility, or whether they are contrivances, deliberately and consciously maintained, for putting sand in the wheels of the State whenever those wheels threaten to revolve in other directions, or more rapidly, than officials approve. AVe call our officials "civil servants " of the Crown. The danger is that they may consciously become, if they are not already, civil masters of the community. In this danger may lie one of the gravest menaces to public freedom, unless adequate safeguards are sought and applied in time. I feel no hostility towards officials either individually or as a class. The majority of them are upright, hardworking men, some of whom constantly save the community from the effects of mini- sterial incompetence. It may indeed be said that without permanent officials drawn from the most intelligent and best educated classes of the community, the parliamentary system would be unworkable and continuity in administrative methods impossible. These high per- minent officials might often, in other circumstances, have become 110 Mr. H. Wickham Steed [May 4, true statesmen, but the great influence they wield is vitiated by their lack of publicly ascertainable responsibility. It is this lack of direct responsibility, that is to say, of risk, that constitutes the danger of officialdom. In some democratic communities a remedy has been sought in the system of " recall," that is to say, in the appointment and dismissal of officials l)y popular vote. This system is undeniaVjly vicious. It tends towards instability and administrative anarchy. But the other extreme of entrusting an ever-increasing volume of pubhc power to an ever-increasing body of practically intangible officials is scarcely less dangerous. The essence of the bureaucratic or official spirit is indeed dislike of responsibility outside the, generally narrow, limits of the official's special functions ; and the exercise of absolute authority within those limits. Subservience towards superiors, out of a spirit of discipline or for the purpose of self-advancement, is apt to be accompanied by arrogance towards inferiors and towards the public. By degrees, officials tend to lose the notion of liberty. They have little them- selves and can hardly be expected to be careful of the liberties of others. They are parts of a machine ; and, in a machine, moral courage and individual initiative are apt to be disturbing factors. They are the victims of a system of division of labour which, while -excellent and indeed indispensable in mechanical production, tends to make automata of human beings who cannot thrive and develop, morally or mentally, without a constant sense of individual risk and responsibility. Like all rigid organizations, departments of State with their limitations of responsibility for those whom they employ, tend to generate a caste spirit which often replaces the sense of the larger duties of citizens. Often, too, acute rivalry grows up between the ■officials of different departments, who come to regard the object of securing advantages for their own departments as more important than the supreme object of ensuring public welfare. Their functions render them imperfect citizens and, to that extent, detract from their fitness as members of the body politic. During the war we have seen a vast and rapid increase of officialdom. The extension of State control over industry, railways, mines, shipping, canals, to say nothing of the introduction of compulsory military service and the whole work of national registration and national mobiliza- tion, implies an innnense increase in the army of officials. It can- not Ije supposed that the new departments and sub-departments of State will disappear Avith the advent of peace and that things will revert automatically to the status quo ante helium. These new organizations will tend to become permanent, to regard themselves as ends in themselves, to acquire a corporate consciousness, and to defend by every means in their power what will have become vested bureaucratic interests. The very numbers of the men and women they employ will make of them potential electoral clienteles whose 1917] on Some Guarantees of Liberty 111 aspirations and grievances will attract the demagogue. Upon the unofficial section of society will fall the burden of maintaining the legions of new "public servants" who will come more and more, unless adequate safeguards be provided, to regard themselves as masters of the public. What are these safeguards, and where is the remedy ? There is no absolute remedy, no universally effective safeguard. The quality and indepQndence of Parliament may perhaps improve. But, in view of past experience, it would be ingenuous to suppose that Parliaments will cease to be machine-made or that the " caucus " and the electoral mechanism which it controls will not continue to eliminate the spirit of independence from among the "representatives of the people." The only true safeguard lies in the political educa- tion of the people — including that of coming generations of civil servants — and in the cultivation of a spirit of independence and economic self-reliance among individuals. The liberal doctrine of the State must be inculcated upon the young, and officials must be regarded — inasmuch as they will have sacriticed some part of their individual freedom for the sake of safe and permanent employment — as citizens belonging to a category a little lower than that of the unofficial memljers of the community. Cases of official arrogance, obstruction or ineptitude must be publicly exposed — but let those who expose them be prepared for the pertinacious, clannish resentment of the immediate colleagues of offenders, if not of the whole official class I The law of libel may need modification and clarification. Publicity, combined with a healthy spirit of individual independence, is perhaps the greatest safeguard — and in this respect heavy respon- sibility will devolve upon the Press. It is true, in a sense, that the public usually has the kind of Press it deserves : but it is important that, in a free community, the organs of public opinion should be numerous enough not to fall wholly under the control of any one party or financial interest ; that they should be wealthy enough not to be entirely corrupted or "influenced," disinterested enough not to become altogether commercialized, and high-minded enough not to pander to public vices or to yield to public clamour. But, when all is said and done, the problem of preserving individual freedom in an organized community is a problem of moral and political education, a problem of knowledge of the essential condi- tions of freedom and of the will to use it. There is no panacea, but there is, in the education of citizens to a sense of their duties and of their rights, to a love of liberty, to a hatred of tyi'anny, small and great, to moral courage, truthfulness and uprightness, a very potent safeguard against the evils that may threaten us when once the menace of the outer foe shall have been overcome. [H. W. S.] 112 General Monthly Meeting [May 7, GENERAL MOXTHLY MEETIXG, Monday, May 7, 1917. Sir James Crichtox-Browxe, J.P. M.D. LL.D. D.Sc F.R.S., Treasurer and Yice-President, in the Chair. Lady Bax-Ironside, Sir J. Stirling Maxwell, Bt., Helena F. Mond, were elected Members. The Chairman read the following letter, which had been received from the Honorary Member elected at the General Meeting on December 1, 191G : — MiXISTERE DE LA GUERKE, Republique FRAN9AISE, Paris : le 2 Mai, 1917. Messieurs, Vous voudrez bien ne pas me tenir rigueur de I'extreme retard que j'apporte a m'acquitter euvers vous. La seule excuse que j'invoque m'est fournie par les circonstances ; au moment ou je recus notification du haut honneur que vous m'avez confere, j'exercais les fonctions de Ministre des Inventions de Guerre; j'ai aujourd'hui la lourde charge de presider a I'organisation de notre defense nationale. La distinction dont le suis I'objet, Messieurs, de la part de votre illustre Compagnie, m'est precieuse a bien des titres. D'abord, parce que peu de mes compatriotes I'ont obtenue au nombre desquels fut le grand Pasteur ; et c'est I'une succession dont meme un membre de I'lnstitut de France a quelque raison de s'intimider. Ce qui me fait, ensuite et surtout, attaeher un prix particulier a I'honneur d'avoir ete cboisi par vous pour faire partie de votre Assemblee, c'est que ce choix s'est manifeste en pleine guerre alors que nos deux pays combattent c6t6-a-c6te le combat du droit. Puissent ainsi toutes les forces intellectuelles et toutes les ressources scientifiques de I'Angleterre et de la France hater la victoire de nos armes et assurer pour jainais dans le monde la suprematie de la pensee sur la violence. Messieurs les membres de la Royal Institution, je vous prie d'agreer I'expression de ma consideration la plus distinguce et de mon d6vouement fraternel. Le Ministre de la Guerre, Membre de I'lnstitut, PAUL PAINLEVE. 1917] General Monthly Meeting 113 The PnESEXTS received since the last Meeting were laid on the table, and the thanks of the Members returned for the same, viz. : — FROM The Secretanj of State for India— Annual Report on Kodaikanal and ^Madras Observatories for 1916. 4to. Report on Progress of Agriculture in India for 1915-16. 8vo. 1917. Accademia del Lincei, Reale, Roma — Rendiconti, Classe di Scienze Fisiche, Mathematiche e Naturali. Serie Quinta, Vol. XXVI. 1*^ Semestre, Fasc. 6-S. Svo. 1917. Accountants. Association of — Journal for May 1917. Svo. American Chemical Societi/^Jonvudil for May 1917. Svo. Journal of Industrial and Engineering Chemistry for May 1917. Svo. American Geographical Society — Geographical Review for May 1917. Svo. American Journal of Physiology — Vol. XLIII. Nos. 1-2. Svo. 1917. Astronomical Society, Royal — Monthly Notices, Vol. LXXVII. Nos. 5-6. 1917. Svo. Bankers, Institute o/— Journal, Vol. XXXVIII. Part V. May 1917. Svo. British Architects, Royal Institute of — Journal, Third Series, Vol. XXIV. No. 9. 4to. 1917. British Astronomical Association — Journal, Vol. XXVII. No. 6. Svo. 1917. Buenos Aires — Monthly Bulletin of Municipal Statistics for Nov.-Dec. 1916. 4to. Canada, Department of JUines— Museum Bulletin, No. 26. Svo. 1917 ; Nos. S8 & 91. Svo. 1916-17. Geological Survey Memoirs. Carnegie Institution of Washington — Annual Report of the Director of Depart- ment of Terrestrial Magnetism for Year 1916. Svo. Chemical Industry, Society of — Journal, Vol. XXXVI. Nos. S-9. Svo. 1917. Chemical Society — Journal for May 1917. Svo. East India Association — Journal, New Series, Vol. VIII. No. 2. Svo. 1917. Editors — Aeronautical Journal for Jan.-March 1917. Svo. Athenaeum for May 1917. 4to. Author for May 1917. Svo. Chemical News for May 1917. 4to. Chemist and Druggist for May 1917. Svo. Church Gazette for May 1917. Svo. Concrete for May 1917. Svo. Dyer and Calico Printer for May 1917. 4to. Electrical Engineering for May 1917. 4to. Electrical Industries for ]May 1917. 4to. Electrical Times for May 1917. 4to. Electricity for May 1917. Svo. Engineer for May 1917. fol. Engineering for May 1917. fol. General Electric Review for May 1917. Svo. Horological Journal for May 1917. Svo. Illuminating Engineer for May 1917. Svo. Journal of Physical Chemistry for April 1917. Svo. Journal of the British Dental Association for May 1917. Svo. Junior Mechanics for May 1917. Svo. Law Journal for May 1917. Svo. Marine Magazine for May 1917. 4to. Model Engineer for May"^1917. Svo. Musical Times for May 1917. Svo. Nature for May 1917. 4to. New Church Magazine for May 1917. Svo. Nuovo Cimento for Sept. 1916. Svo. YoL. XXII. (Xo. Ill) I 114 General Monthly Meeting [May 7, Editors — contimied Page's Weekly for May 1917. 8vo. Physical Review for April 1917, 8vo. Power for May 1917. 8vo. Power-User for May 1917. Svo. Science Abstracts for April 1917. Svo. Tcheque, La Nation, for April 1917. Svo. War and Peace for Mav 1917. Svo. Wireless W^orld for May 1917. Svo. Zoophilist for May 1917, Svo. Electrical Engineers, Institution o/— Journal, Vol. LV. Nos. 265-266. Svo. 1917. Florence, Biblioteca Nazionale Centrale — Bollettino for April-May 1917. Svo. Franklin Institute — Journal, Vol. GLXXXIII. No. 5, May 1917, Svo. Geneva, SociUe de Physique — Memoires, Vol. XXXIX. Fasc. 1. 4to. 1916. Geographical Society, Royal — Journal, Vol. XLIX. No. 5. Svo. 1917. Geographical Society, Scottish — Magazine for May 1917. Svo. Geological Society of London — Quarterly Journal, Vol. LXXII. Part 1. Svo. 1917. Abstracts of Proceedings, Nos. 1006-S. Svo. 1917. Jugoslav Committee — Southern Slav Bulletin, No. 30. 1917. Eiverpool, Literary and Philosophical Society of- — Proceedings, Vol. LXIV, Svo. 1916. London County Council — Gazette for May 1917, 4to. London Society — Journal for May 1917. Svo, Manchester Literary and Philosophical Society— IsLe-Diohs and Proceedings, Vol. LX. Part 3, Svo, 1917. Meteorological Office — Weekly Weather Reports for April-May 1917. Ito, Daily Readings for March 1917, 4to. Monthly Weather Reports for April 1917. 4to, Geophysical Journal for July 1915. Meteorological Society, Royal — Journal, Vol. XLIII. April 1917. Svo. Microscopical Society, Royal — Journal, April 1917, Svo. Monaco, Musee Oceanograpliique—BuWeim, Nos. 323-325. Svo. 1917. Montpellier Academic des Sciences — Bulletin, Nos. 2-4. 1917. Svo. New South Wales, Royal Society o/^Journal and Proceedings, Vol. L. Part 1, Svo. 1916. New York, Society for Experimental Biology — Proceedings, Vol. XIV. Nos. 5-6. Svo. 1917. New Zealand, High Commissioner for — Patent Office Journal, May 1917. Svo. Statistics, 1915, Vol. II. 4to. Paris, Soci(He d' Encouragement pour V Industrie Nationale — Bulletin for March-April 1917. 4to. 1917. Pharmaceutical Society of Great Britain — Journal for May 1917. Svo. Photographic Society, Royal — Journal, Vol. LVII. No. 5. Svo. 1917. Physical Society of London — Proceedings, Vol, XXIX. Part 3. Svo. 1917. Princeton University Observatory — Contributions from, No. 4. 4to. 1916. Royal Colonial Institute — United Empire, Vol. VIII. Na 5. Svo. 1917. Royal Engineers' Institute — Journal, Vol. XXV. No. 6. Svo. 1917. Royal Irish Academy — Proceedings, Vol. XXXIII. Section A, No. 6 ; Section B, Nos. 4-6; Section C, Nos. 12-19. Svo. 1917. Royal Society of Arts — Journal for May 1917. Svo. Royal Society of London — Proceedings, A, Vol. XCIII. Nos. 649-650 ; B, Vol, LXXXIX. No. 620. Svo. 1917. Selborne Society — Selborne Magazine for May 1917. Svo. Smithsonian Institution— 'Miscellsmeous Collections, Vol. LXVI, Nos. 11-13, 15. Svo. 1916. Societd degli Spettroscopisti IteZiani— Memorie, Series 2, Vol. VI. Disp. 2. 4to. 1917. Statistical Society, i?07/aZ— Journal, Vol. LXXX, Part 2, March 1917. Svo. 1917] Radioactive Haloes 115 Stonyhurst College Observatory — Eesults of Meteorological, Magnetical and Seismological Observations, 1916. 8vo. 1917. United Service Institution, Royal— J onrnsil for May 1917. 8vo. TJnited States Army, Surgeon-GcneraV s Office — Index-Catalogue of the Library, Second Series, Vol. XXI. 8vo. 1916. United States, Department of Agriculture — Journal of Agricultural Research, Vol. IX. Nos. 3-7,- 1917. 8vo. Experiment Station Record, Vol. XXXVI. Nos. 4-5. Svo. 1917. United States Department of the Interior — Geological Survey, Bulletins, Nos. 627, 630, 635, 636, 638, 610 b, d, e ; 641 b, c, d, e ; 645, 649. Professional Papers : Nos. 91 ; 98 i, J, k, m, x. Water Supply Papers : Nos. 360, 384, 387, 395. Svo. 1916. Mineral Resources, 1915, Part 1, Nos. 1, 3, 4, 5, 7 ; Part 2, Nos. 12-14, 16-17, 19-20. Svo. 1916. Upsala, Boyal Meteorological Observatory — Bulletin, Vol. XLVIII. 4to. 1916-17. Western Australia, Agent-General — Statistical Abstracts, Aug.-Nov. 1916. 4to. WEEKLY EYEXING MEETIXCx, Friday, May 11, 1017. Sir James Crichtox-Browxe, J.P. M.D. LL.D. D.Sc. F.R.S., Treasurer and Yice-President, in the Chair. Professor Johx Joly, M.A. D.Sc. F.Pt.S. Radioactive Haloes. These minute objects have long been known to petrologists, but their explanation is of recent date. They are formed around particles containing radioactive matter and are caused by an effect of the alpha radiations on certain minerals of the ferro-magnesium group. Radioactive haloes may, therefore, be derived from uranium or thorium, and the series of alpha-ray changes characteristic of the radioactive transformations originated by these parent substances determine the dimension and structure of the halo. It is easy to refei' a well developed halo to one or other of these parent substances. The uranium series of elements gives rise to eight alpha-ray emitting substances, each of special and characteristic range. The thorium series of elements gives rise to seven alpha-rays of charac- teristic range. It is found that when the integral ionization of these rays, as defined by the Bragg curve of ionization for each ray, is determined by the simple process of adding the ordinates of the eight or seven several curves plotted to the same axes of reference, the two resulting curves (i.e. that for the uranium series and that for the thorium series) agree with the features of uranium and thorium haloes. I 2 IIG Radioactive Haloes [May 11, But in order to account for the mode of development of the halo, i.e. the sequence in which its several features appear, it is further necessary to assume that some cause exists which favours the development of the outer features, or in other words counteracts the weakening of the ionization arising from the spreading of the rays from the radioactive nucleus of the halo. In it is found that the inner ring which marks the first beginning of the halo may be attended by the appearance of the outermost ring due to the alpha- ray of greatest range ; an effect which should not occur if the ionization intensity fell off with the divergence of the rays, as might be expected. The explanation offered is that the halo-genesis follows similar laws to those governing photographic effects, so that repetition of stimuli leads to reversal of the earlier effects. Reversal will therefore be less active as the rays diverge outwards, and lierein is found a reason for the relative accentuation of the ionization due to the rays of longest range. Haloes presenting all the appearance of more complete reversal have been observed. The foregoing principles satisfactorily explain the features, dimensions, and order of formation of haloes formed around radio- active centres. A third type of halo is observed which is referable to the emanation of radium as parent substance. This halo appears generally in connexion with conduits in which there is plain evidence that radioactive gas or liquid has at one time circulated. The nucleus of the halo has apparently absorbed the emanation, and the further changes of this substance, giving rise to four characteristic alpha-rays, have sufficed to form a halo which finds, in its every feature, explanation according to the principles outlined above. There is some degree of misfit in the primal rings of both the thorium and the uranium halo. In the case of the thorium halo this misfit is very minute, but is sufficient to suggest that the range generally accepted for the thorium alpha-ray is a little excessive. This agrees with the indication of the Geiger-Xutall curve, connect- ing range and period of transformation. In the case of the primal ring of the uranium halo — which is largely due to the ionization arising from Uj and Uo — the misfit is more conspicuous, and is in the opposite sense to the misfit of the thorium ray. The observed halo-ring indicates a former range greater than what is now observed. Until tliis misfit is shown to be confined to halves of Palaeozoic or Arch^an ages it seems premature to advance any explanation of it. It is worth noting, however, that a former longer range of the ray of Uj, and hence a more rapid rate of decay of uranium in early times, would explain the disagreement of the lead-ratio of the uranium series with that of the thorium series, and concurrently would reconcile radioactive methods of determining the earth's age with those based on the indications of denudative effects. [J. J.] 1917] The Complexity of the Chemical Elements 117 AVEEKLY EYEXIXG MEETIXG, Friday, May 18, 1917. Sir William Phipsox Beale, Bart., K.C. M.P., Yice-Presideut, in the Chair. Professor Frederick Soddy, M.A. F.R.S. The Complexity of the Chemical Elements. The elements of the chemist are now known to be complex in three different senses. In the first sense the complexity is one that concerns the general nature of matter, and therefore of all the elements in common to greater or less degree. It follows from the relations between matter and electricity which have developed gradually during the past century as the result of experiments made and theories born within the four walls of this Institution. Associ- ated initially with the names of Davy and Faraday, they have only in these days come to full fruition as the result of the very brilliant elucidation of the real nature of electricity by your distinguished Professor of Physics, Sir Joseph Thomson. Such an advance, developing slowly and fitfully, with long intervals of apparent stagnation, needs to be reviewed from generation to generation, disentangled from the undergrowth that obscures it, and its clear conclusions driven home. This complexity of the chemical elements is a consequence of the condition that neither free electricity nor free matter can be studied alone, except in very special phenomena. Our experimental knowledge of matter in quantity is necessarily confined to the complex of matter and electricity which constitutes the material world. This applies even to the " free " elements of the chemist, which in reality are no more free then than they are in their compounds. The difference is merely that, whereas in the latter the elements are combined with other elements, in the so-called free state they are combined with electricity. I shall touch l)ut briefly on this first aspect, as in principle it is now fairly well under- stood. But its consistent and detailed application to the study of chemical character is still lacking. The second sense in which the elements, or some of them at least, are known now to be complex has, in sharp contrast to the first, developed suddenly and startlingly from the recognition in radio- active changes, of different radio-elements, non-separable by chemical lis Professor Frederick Soddy [May 18, means, now called isotopes. The natural coroUaiy of this is that the chemical element represents rather a type of element, the members of the type being only chemically alike. Alike they are in most of those properties, ^yhich were studied prior to the last decade of last century and which are due, as we now think, to the outer shells of the atom, so alike that all the criteria, hitherto relied upon by the chemist as being the most infallible and searching, would declare them to be identical. The apparent identity goes even deeper into the region reached by X-ray spectrum analysis which fails to distinguish between tliem. The difference is "^ found only in that innermost region of all, the nucleus of the atom, of which radio- active phenomena first made us aware. But, though these phenomena pointed the way, and easily showed to be different what the chemist and spectroscopist would have decided to be identical, it did more. It showed that although the finer and newer criteria, relied upon by the chemist in his analysis of matter, must of necessity fail in these cases, being ultimately electrical in character, yet the difference should be obvious in that most studied and distinctive characteristic of all— the criterion by which Dalton first distinguished the different kinds of atoms — the atomic weight. Those who have devoted themselves to the exact determination of these weights have now confirmed the difference in two separate cases, which, in absence of what perhaps they might regard as " preconceived notions," they were unable to discover for themselves. This is the experimental development to which I wish more especially to direct your attention. It indicates that the chemical analysis of matter is, even within its own province, superfi- cial rather than ultimate, and that there are indefinitely more distinct elements than the ninety-two possible types of element accommodated by the present periodic system. The third sense in which the elements are known to be complex is that which, in the form of philosophical speculations, has come down to us from the ancients, which inspired the labours of the alchemists of the Middle Ages, and which in the form of Front's hypothesis has re-appeared in scientific chemistry. It is the sense that denies to Nature the right to be complex, and from the earliest times, faith out-stripping knowledge, has underlain the belief that all the elements must be built up of the same primordial stuff. The facts of radioactive phenomena have shown that all the radio- elements are indeed made up out of lead and helium, and this has definitely removed the question from the region of pure speculation. We know that helium is certainly a material constituent of the elements in the Proutian sense, and it would be harmless, if probably fruitless, to anticipate the day of fuller knowledge by atom building and unl)uilding on paper. Apart altogether from this, however, the existence of isotopes, the generalisation concerning the Periodic Law that has arisen from the study of radioactive change on the one 1917] on The Complexity of the Chemical Elements 119 hand and the spectra of X-rays on the other, and experiments on the scattering of a-particles by matter, do give us for the first time a definite conception as to what constitntes the difference between one element and another. "We can say how gold would result from lead or mercury, even though the control of the processes necessary to effect the change still eludes us. The nuclear atom proposed by Sir Ernest Rutherford, even though, admittedly, it is only a general and incomplete beginning to a complete theory of atomic structure, enormously simplifies the correlation of a large number of diverse facts. This and what survives of the old electronic theory of matter, in so far as it attempted to explain the Periodic Law, will therefore be briefly referred to in conclusion. The Free Element a Compound of Matter and Electricity. Although Davy and Faraday were the contemporaries of Dalton, it must be remembered that it took chemists fifty years to put the atomic theory on a definite and unassailable basis, so that neither of these investigators had the benefit of the very clear view we hold to-day. Davy was the originator of the first electro-chemical theory of chemical combination, and Faraday's dictum, "the forces of chemical affinity and electricity are one and the same," it is safe to say, inspires all the modern attempts to reduce chemical character to a science in the sense of something that can be measured quan- titatively, as well as expressed qualitatively. Faraday's work on the laws of electrolysis and the discovery that followed from it, when the atomic theory came to be fully developed, that all monovalent atoms or radicles carry the same charge, that divalent atoms carry twice this charge and so on, can be regarded to-day as a simple extension of the law of multiple proportions from compounds between matter and matter to compounds between matter and electricity. Long before the electric charge had been isolated, or the properties of electricity divorced from matter discovered, the same law of multiple proportions which led, without any possibility of escape, to an atomic theory of matter, led, as Helmholtz pointed out in his well-known Faraday lecture to the Chemical Society in this Theatre in 1881, to an atomic theory of electricity. The work of Hittorf on the migration of ions, the bold and upsetting conclusion of Arrhenius that in solution many of the compounds hitherto regarded as most stable exist dissociated into ions, the realisation that most of the reactions that take place instantaneously, and are utilised for the identification of elements in chemical analysis, are reactions of ions rather than of the element in question, made very familiar to chemists the enormous difference between the properties of the elements in the charged and in the electrically neutral state. 120 Professor Frederick Soddy [May 18, More slowly appreciated, and not yet perhaps sufficiently empha- sized, was the unparalleled intensity of these charges in comparison with anything that electrical science can show, which can he expressed tritely by the statement that the charge on a milligram of hydrogen ions would raise the potential of the world 100,000 volts. Or, if we consider another aspect, and calculate how many free hydrogen ions you could force into a bottle without bursting it, provided, of course, that you could do so without discharging the ions, you would find that, were the bottle of the strongest steel, the breech of gun, for example, it would burst, by reason of the mutual repulsion of the charges, before as much was put in as would, in the form of hydrogen gas, show the spectrum of the element in a vacuum tube. Then came the fundamental advances in our knowledge of the nature of electricity, its isolation as the electron, or atom of negative electricity, the great extension of the conception of ions to explain the conduction of electricity through gases, the theoretical reasoning, due in part to Heaviside, that the electron must possess inertia inversely proportional to the diameter of the sphere on which it is concentrated by reason of the electro-magnetic principles discovered by Faraday, leading to the all-embracing monism that all mass may be of electro-magnetic origin. This put the coping-stone to the conclusion that the elements as we apprehend them in ordinary matter are always compounds In the "free" state they are compounds of the element in multiple atomic proportions with the electron. The ions, which are the real chemically uncombined atoms of matter, can no more exist free in quantity than can the electrons. The compound may be individual as between the atom and the electron, or it may be statistical, affecting the total number merely of the opposite charges, and the element presumably will be an insulator or conductor of electricity accordingly. Analogously, with compounds, the former condition applies to unionised compounds such as are met with in the domain of organic chemistry, or ionised, as in the important classes of inorganic compounds, the acids, bases and salts. Just as the chemist has long regarded the union of hydrogen and chlorine as preceded by the decomposition of the hydrogen and chlorine molecule, so he should now further regard the union itself as a decomposition of the hydrogen atom into the positive ion and the negative electron, and a combination of the latter with the chlorine atom. One of the barriers to the proper understanding and quantitative development of chemical character from this basis is, perhaps, the conventional idea derived from electrostatics, that opposite electric charges neutralise one another. In atomic electricity or chemistry, though the equality of the opposite charges is a necessary condition for existence, there is no such thing as neutralisation, or the elec- 1917] on The Complexity of the Chemical Elements 121 tricallj neutral state. Every atom being the seat of distinct opposite charges, intensely localised, the state of electric neutrality can apply only to a remote point outside it, remote in comparison with its own diameter. "We are getting back to the conception of Berzelius, with some possibihty of understanding it, that the atom of hydrogen, for example, may be strongly electro-positive, and that of chlorine strongly electro-negative, with regard to one another, and yet each may be electrically neutral in the molar sense. Some day it may be possible to map the electric field surrounding each of the ninety-two possible types of atom, over distances comparable with the atomic diameter. Then the study of chemical character Avould become a science in Kelvin's sense, of something that could be reduced to a number. But the mathematical conceptions and methods of attack used in electrostatics for macroscopic distances are ill-suited for the purposes of chemistry, which will have to develop methods of its own. AVe have to face an apparent paradox that the greater the affinity that binds together the material and electrical constituents of the atom, the less is its combining power in the chemical sense. In other words, the chemical affinity is in inverse ratio to the affinity of matter for electrons. The helium atoms offer a very simple and instructive case. Helium is non-valent and in the zero family, possessing absolutely no power of chemical combination that can be detected. Yet we know the atom possesses two electrons, for in radioactive change it is expelled without them as the a-particle. The discharge of electricity through it and positive-ray analysis show^ that the electrons, or certainly one of them, are detachable by electric agencies, although not by chemical agencies. One would expect helium to act as a diad, forming helides analogous to oxides. Professor Armstrong for long advocated the view that these inert gases really are endowed with such strong chemical affinities that they are compounds that have never been decomposed. They cer- tainly have such strong affinities for electrons tLat the atom, the complex of the + ion and electrons, cannot be decomposed chemically. Yet, in this case, w^here the affinity of the matter for the electron is at a maximum, the chemical combining power is absent. These gases seem to furnish the nearest standard we have to electric neutrality in the atomic sense. The negative charge of the electrons exactly satisfies the positive charge of the matter, and the atomic complex is chemically, because electrically, neutral. In the case of the electro-positive elements, hydrogen and the alkali- metals, one electron more than satisfies the positive charge on the ion, and so long as the equality of opposite charges is not altered, the electron tries to get away. In the case of the electro-negative elements, such as the halogens, the negative charge, though equal presumably to the positive, is not sufficient to neutralise the atom. Hence these groups show strong mutual affinity, one having more 122 Professor Frederick Soddy [May 18, and the other less negative electricity than would make the system atomically neutral like helium. The electron explains well the merely numerical aspect of valency. But chemical combining power itself seems to require the idea that equal and opposite charges in the atomic sense are only exactly equivalent in the case of the inert gases. None of these ideas are now new, but their consistent application to the study of chemical compounds seems curiously to hang fire, as though something were still lacking. It is so difficult for the chemist consistently to realise that chemical affinity is due to a dissociating as well as to a coml)ining tendency and is a differential effect. There is only one affinity, probably, and it is the same as that between oppositely charged spheres. But, atomic charges being enormous and the distances over which they operate in chemical phenomena being minute, this affinity is colossal, even in comparison with chemical standards. What the chemist recognises as affinity is due to relatively slight differences between the magnitude of the universal tendency of the electron to combine with matter in the case of the different atoms. Over all, is the necessary condition that the opposite charges should be equivalent, but this being satisfied, the individual atoms display the tendencies inherent in their structure, some to lose, others to gain electrons, in order, as we believe from Sir Joseph Thomson's teaching, to accommodate the number of electrons in the outer- most ring to some definite number. Chemical affinity needs that some shall lose as well as others gain. Chemical union is always preceded by a dissociation. The tendency to combine, only, is specific to any particular atom, but the energy and driving power of com- bination is the universal attraction of the + for the - change, of matter for the electron. The Electrical Theory of Matter. Another barrier that undoubtedly exists to the better apprecia- tion of the modern point of view, even among those most willing to learn, is the confusion that exists between the earlier and the present attempt to explain the relation between matter and electricity. AVe know negative electricity apart from matter as the electron. AVe know positive electricity apart from the electron, the hydrogen ion and the radiant helium atom or a-particle of radioactive change for example, and it is matter in the free or electrically uncombined con- dition. Indeed, if you want to find matter free and uncombined, the simple elementary particle of matter in the sense of complexity being discussed, you will go, paradoxically, to what the chemist terms a compound rather than to that which lie terms the free element. If this compound is ionised completely it constitutes the nearest approach to matter in the free state. Thus all acids owe their common acidic quality to really free hydrogen, the hydrogen' ion, a 1917] on The Complexity of the Chemical Elements 123 particle more different from the hydrogen atom than the atom is from the hydroji-en molecule. Positive electricity is thus emphatically not the mere absence of electricity, and any electrical theory of matter purporting to explain matter in terms of electricity does so by the palpable sophistry of calling two fundamentally different things by the same name. The dualis'm remains whether you speak of matter and electricity, or of positive and negative electricity, and the chemist would do well to stick to his conception of matter, until the physicist has got a new name for positive electricity which will not confuse it with the only kind of electricity that can exist apart from matter. On the other hand, the theory of the electro-magnetic origin of mass or inertia is a true monism. It tries to explain consistently two things — the inertia of the electron and the inertia of matter— by the same cause. The inertia of the former being accounted for by the well-known electro-magnetic principles of Faraday, by the assumption that the charge on the electron is concentrated into a sphere of appropriate radius ; the 2000-fold greater inertia of the hydrogen ion, for example, can be accounted for by shrinking the sphere to one- two-thousandth of the electronic radius. But the electrical dualism remains completely unexplained. Call the electron E and the hydrogen ion H. The facts are that two E's repel one another with the same force and according to the same law as two H's repel each other, or as an H attracts an E. These very remarkable properties of H and E are not explained by the explana- tion of the inertia. Are E and H made up of the same stuff or of two different stuffs ? We do not know, and certainly have no good reason to assume, that matter minus its electrons is made of the same thing as the electron. We have still to reckon with two different things. The Chemical Elements not necessarily Homogeneous. I pass now to the second and most novel sense in which the elements, or some of them at least, are complex. In their discovery of new radioactive elements, M. and Mme. Curie used radioactivity as a method of chemical analysis precisely as Bunsen and Kirchoff", and later Sir William Crookes, used spectrum analysis to discover caesium and rubidium, and thalUum. The new method yielded at once, from uranium minerals, three new radio-elements, radium, polonium and actinium. According to the theory of Sir Ernest Ptutherford and myself, these elements are intermediate members in a long sequence of changes of the parent element uranium In a mineral the various members of the series must co-exist^ in equi- librium, provided none succeed in escaping from the mineral, in quantities inversely' proportional to their respective rates of change, or directly proportional to their periods of average life. Ptadium 12-4 Professor Frederick Soddy P^aj 18, chansfes sufficiently slowly to accumulate in small but ponderable quantity in a uranium mineral, and so it was shown to be a new member of the alkaline-earth family of elements, with atomic weight i2G*0, occupying a vacant place in the Periodic Table. Polonium changes 4500 times more rapidly, and can only exist to the extent of a few hundredths of a milligram in a ton of uranium mineral. Actinium also, though its life period is still unknown, and very possibly is quite long, is scarce for another reason, that it is not in the main line of disintegration, but in a branch series which claims only a few per cent of the uranium atoms disintegrating. In spite of this, polonium and actinium have just as much right to be con- sidered new elements, probably, as radium has. Polonium has great resemblances in chemical character both to bismuth and tellurium, but was separated from the first by Mme. Curie and from the second by Marckwald. In the position it occupies as the last member of the sulphur group, bismuth and tellurium are its neighbours in the Periodic Table. Actinium resembles the rare-earth elements, and most closely lanthanum, but an enrichment of the proportion of actinium from lanthanum has been effected by Giesel. The small- ness of the quantities alone prevents their complete separation in the foi'm of pure compounds as was done for radium. The three gaseous members, the emanations of radium, actinium and thorium, were put in their proper place in the Periodic Table almost as soon as radium was, for, being chemically inert gases, their characterisation Avas simple. They are the last members of the argon family, and the fact that there are three of about the same atomic weight was probably the first indication, although not clearly appreciated, that more than one chemical element could occupy the same place in the Periodic Table. The extension of the three disintegration series proceeded apace ; new members were being continually added, but no other new radio- elements — new, that is, in possessing a new chemical character — were discovered. The four longest-lived to be added, radio-lead or radium-D, as it is now more precisely termed, and ionium in the uranium series, and mesothorium-I and radiothorium in the thorium series, could not be separated from other constituents always present in the minerals, radium-1) from lead, ionium and radiothorium from thorium, and mesothorium-I from radium. An appreciable pro- portion of the radioactivity of a uranium mineral is due to radium-D and its products, and its separation would have been a valuable technical achievement, but, though many attempts have made, this has never been accomplished, and, we know now, probably never will be. Seven years ago it was the general opinion in the then compara- tively undeveloped knowledge of the chemistry of the radio-elements, that there was nothing especially remarkable in this. The chemist is familiar with many pairs or groups of elements, the separation of 1917] on The Complexity of the Chemical Elements 125 which is laborious and difficult, and the radio-chemist had not then fully appreciated the power of radioactive analysis in detecting a very slight change in the proportions of two elements, one or both of which were radioactive. The case is not at all like that of the rare-earth group of elements, for example, in which the equivalent or atomic weight is used as a guide to the progress of the separation. Here the total difference in the equivalent of the completely separated elements is only a very small percentage of the equivalent, and the separation must already have proceeded a long way before it can be ascertained. Human nature plays its part in scientific advances, and tlie chemist is human like the rest. My own views on the matter developed with some speed when, in 1010, I came across a new case of this phenomenon. Trying to find out the chemical character of mesothorium-I, which had been kept secret for technical reasons, I found it to have precisely the same chemical character as radium, a discovery which was made in the same year by Marckwald, and actually first published by him. I delayed my publication some months to complete a very careful fractional crystallisation of the barium-radium-mesothorium-I chloride separated from thorianite. Although a great number of fractionations were performed, and the radium was enriched, with regard to the barium, several hundred times, the ratio between the radium and mesothorium-I was, within the very small margin of error possil^le in careful radioactive measurements, not affected by the process. I felt justified in con- cluding from this case, and its analogy with the several other similar cases then known, that radium and mesothorium-I were non-separable by chemical processes, and had a chemical character not merely like, but identical. It followed that some of the common elements might similarly be mixtures of chemically identical elements. In the cases cited, the non-separable pairs differ in atomic weight from 2 to 4 units. Hence the lack of any regular numerical relationships between the atomic weights would on this view follow naturally. (Trans. Chem. Soc. 1911, xcix. 72.) This idea was elaborated in the Chemical Society's Annual Report on Radioactivity for 1910, in the concluding section summing up the position at that time. This was I think the beginning of the conception of different elements identical chemically, which later came to be termed "isotopes," though it is sometimes attributed to K. Fajans, whose valuable con- tributions to radioactivity had not at that date commenced, and whose first contribution to this subject did not appear till 1918. In the six or seven years that have elapsed the view has received complete vindication. Really, three distinct lines of advance con- verged to a common conclusion, and, so far as is possible, these may be disentangled. First, there has been the exact chemical charac- terisation from the new point of view of every one of the members of the three disintegration series, with lives over one minute. 12G Professor Frederick Soddy [May 18, Secondly, came the sweeping generalisations in the interpretation of the Periodic Law. Lastly, there has been the first beginnings of our experimental knowledge of atomic structure, which got beyond the electronic constituents and at the material atom itself. Li pursuance of the first, Alexander Fleck, at my request, com- menced a careful systematic study of the chemical character of all the radio- elements known of which our knowledge was lacking or imperfect, to see which were and which were not separable from known chemical elements. Seldom can the results of so much long and laborious chemical work be expressed in so few words. Every one, that it was possible to examine, was found to be chemically identical either with some common element or with another of the new radio-elements. Of the more important characterisations, mesothorium-II was found to be non-separable from actinium, radium-A from polonium, the three B-members and radium-D from lead, the three C-members and radium-E from bismuth, actinium-D and thorium- D from thallium. These results naturally took some time to complete, and became known fairly widely to others working in the subject before they were published, through A. S. Russell, an old student, who was then carrying on his investigations in radioactivity in Manchester. Their interpretation constitutes the second line of advance. Before that is considered, it may first be said that every case of chemical non-separability put forward has stood the test of time, and all the many skilled workers who have pitted their chemical skill against Nature in this quest have merely confirmed it. The evidence at the present day is too numerous and detailed to recount. It comes from sources, such as in the technical extraction of meso- thorium from monazite, where one process is repeated a nearly endless number of times ; from trials of a very great variety of methods, as, for example, in the investigations on radium-I) and lead by Paneth and von Hevesy ; it is drawn from totally new methods, as in the Ijeautiful proof by the same authors of the electro-chemical identity of these two isotopes ; it is at the basis of the use of radio- active elements as indicators for studying the properties of a common element, isotopic with it, at concentrations too feeble to be otherwise dealt with, imd from large numbers of isolated observations, as well as prolonged systematic researches. One of the finest examples of the latter kind of work, the Austrian researches on ionium, will be dealt with later. The most recent, which appeared last month, is by T. W. Richards and N. F. Hall, who subjected lead from Australian carnotite, containing therefore radium-D, to over a thousand fractional crystallisations in the form of chloride, without appreciably altering the atomic weight or the y8-activity. So that it may be safely stated that no one who has ever really tested this conclusion now doubts it, and after all they alone have a right to an o]tinion. This statement of the non-separal)ility by chemical methods of 1917] on The Complexity of the Chemical Elements 127 pairs or groups of elements suffers perhaps from being in a negative form. It looks too much like a mere negative result, a failure, but in reality it is one of the most sweeping positive generalisations that oould be made. Ionium we say is non-separable from thorium, but every chemist knows thorium is readily separated from every other known element. Hence, one now knows every detail of the chemistry of the vast majority of these new radio-elements by proxy, even when their life is to be measured in minutes or seconds, as completely as if they were obtainable, like thorium is, by the ton. The difference it makes can only be appreciated by those who have lived through earlier days, when, in some cases dealing with the separation of radio-consUtuents from complex minerals, after every chemical separation one took the separated parts to the electroscope to find out where the desired constituent was. As the evidence accumulated that we had to deal here with some- thing new and fundamental, the question naturally arose whether the spectrum of isotopes would be the same. The spectrum is known, like the chemical character, to be an electronic rather than mass phenomenon, and it was to be expected that the identity should extend to the spectrum. The question has been tested very thoroughly by A. S. Russell and R. Rossi in this country, and by the Austrian workers at the Radium Institnt of Vienna, for ionium and thorium, and by various workers for the various isotopes of lead. Xo certain difference has been found, and it may be concluded that the spectra of isotopes are identical. This identity probably extends to the X-ray spectra, Rutherford and Andrada having shown that the spectrum of the y-rays of radium-B is identical with the X-ray spectrum of its isotope, lead. The Periodic Law axd Radioactive Chaxge. The second line of advance interprets the Periodic Law. It began in 1911 with the observation that the product of an a-ray change always occupied a place in the Periodic Table two places removed from the parent in the direction of diminishing mass, and that in subsequent changes where a-rays are not expelled the product frequently reverts in chemical character to that of the parent, though its atomic weight is reduced 1 units by the loss of the a-particle, making the passage across the table curiously alternating. Thus the product of radium (Group II) by an a-ray change is the emanation in the zero group, of ionium (Group lY), radium, and so on, while, in the thorium series, thorium (Group IV) produces by an a-ray change mesothorium-I (Group II), which, in subsequent changes in which no a-rays are expelled, yields radio-thorium, back in Group IV again. (Chemistry of the Radio-Elements, p. 29, 1st Edition, 1911.) Xothing at that time could be said about ^-ray changes. The products were for the most part very short-lived and imperfectly 128 Professor Frederick Soddy piay 18, characterised chemically, and several lacunifi still existed in the series masking the simplicity of the process. But early in 1913 the whole scheme became clear, and was pointed out first by A. 8. Eussell, in a slightly imperfect form, independently by K. Fajans from electro- chemical evidence, and by myself, in full knowledge of Fleck's results, still for the most part unpublished, all within the same month of February. It was found that, making the assumption that uranium-X was in reality two successive products giving ^-rays, a prediction Fajans and Gohring proved to be correct within a month, and a slight alteration in the order at the beginning of the uranium series, every a-ray change produced a shift of place as described, and every /?-ray change a shift of one place in the opposite direction. Further and most significantly, when the successive members of the three disintegration series were put in the places in the table dictated by these two rules, it was found that all the elements occupying the same place were those which had been found to be non-separable by chemical processes from one another, and from the element already occupying that place, if it was occupied, before the discovery of radioactivity. For this reason the term " isotope " was coined to express an element chemically non-separable from the other, the term signifying " the same place." So arranged, the three series extended from uranium to thallium, and the ultimate product of each series occupied the place occupied by the element lead. The ultimate products of thorium should, because six a-particles are expelled in the process, have an atomic weight 24 units less than the parent, or about 208. The main ultimate product of uranium, since eight a-particles are expel ied in this case, should have the atomic weight 206. The atomic weight of ordinary lead is 207 • 2, which made it appear very likely that ordinary lead was a mixture of the two isotopes, derived from ui'anium and thorium. The prediction followed that lead, separated from a thorium mineral, should have an atomic weight about a unit higher, and that separated from uranium minerals about a unit lower, than the atomic weight of common lead, and in each case this has now been satisfactorily established. The AT03IIC Weight of Lead FRo:\r Radioactive Minerals. It should be said that Boltwood and also Holmes had, from geological evidence, both decided definitely against it being possible that lead was a product of thorium, because thorium minerals contain too little lead, in proportion to the thorium, to accord with their geological ages. AVhereas, the conclusion that lead was the ultimate product of the uranium series had been thoroughly established by geological evidence, and has been the means, in the hands of skilful investigators, of ascertaining geological ages with a degree of pre- 1917] on The Complexity of the Chemical Elements 129 cision not hitherto possible. Fortunately I was not deterred by the non possumus, for it looks as if everybody was right ! An explanation of this paradox will later be attempted. In point of fact, there are exceedingly few thorium minerals that do not contain uranium, and since the rate of change of uranium is about 2 ' 6 times that of thorium, one part of uranium is equal as a lead-producer to 2 • 6 parts of thorium. Thus Ceylon thorianite, one of the richest of thorium minerals, containing 60 to 70 per cent of ThO.,, may contain 10 to 20 and even 30 per cent of UgO^, and the lead from it may be expected to consist of very similar quantities of the two isotopes, to be in fact very similar to ordinary lead. I know of only one mineral which is suitable for this test. It was discovered at the same time as thorianite, and from the same locality — ^Ceylon thorite, a hydrated silicate containing some 57 per cent of thorium and 1 per cent of uranium only. In the original analysis no lead was recorded, but I found it contained 0 • 4 per cent, which, if it were derived from uranium only, would indicate a very hoary ancestry, comparable, indeed, with the period of average life of uranium itself. On the other hand, if (1) all the lead is of radioactive origin, (2) is stable, and (8) is derived from both constituents, as the generalisation being discussed indicated, this O'-l per cent of lead should consist 95*5 per cent of the thorium isotope and 4 • 5 per cent of the uranium isotope. Thorite thus offered an extremely favourable case for examination. In preliminary experiments in conjunction with H. Hyman, in which only a gram or less of the lead was available, the atomic weight was found relatively to ordinary lead to be perceptibly higher, and the difference, rather less than one-half per cent, was of the expected order. I was so fortunate as to secure a lot of 30 kilos, of this unique mineral, which was first carefully sorted, piece by piece, from admixed thorianite and doubtful specimens. From the 20 kilos, of first grade thorite, the lead was separated, purified, reduced to metal, and cast in vacuo into a cylinder, and its density determined together with that of a cylinder of common lead similarly purified and prepared. Sir Ernest Rutherford's theory of atomic structure, to be dealt with in the latter part of this discourse, and the whole of our knowledge as to what isotopes were, made it appear probable that their atomic volumes, like their chemical character and spectra, should be identical, and therefore that their density should be proportional to their atomic weight. The thorite lead proved to be 0*26 per cent denser than the common lead. Taking the figure 207*2 foi'Hhe atomic weight of common lead, the calculated atomic weight of the specimen should be 207 '71:. The two specimens of lead were fractionally distilled in vacuo, and a comparison of the atomic weights of the two middle fractions made by a development of one of Stas's methods. The lead was converted into nitrate in a quartz vessel, and then into chloride by a Vol. XXII. (Xo. Ill) k 130 Professor Frederick Soddy [May 18, current of hydrogen chloride, in which it was heated at gradually increasing temperature to constant weight. Only single determina- tions have been done, and they gave the values 207*20 for ordinary lead, and 207*694 for the thorite lead, figures that are in the ratio of 100 to 100*24:. This therefore favoured the conclusion that the atomic volume of isotopes is constant. At the request of Mr. Lawson, interned in Austria, and continuing his researches at the Radium Institut under Prof. Stefan Meyer, the first fraction of the distilled thorite lead was sent him, so that the work could be checked. He reports that Professor Honigschmid has carried through an atomic weight determination by the silver method, obtaining the value 207*77 ± 0*014, as the mean of eight determinations. Hence, the conclusion that the atomic weight of lead derived from thorite is higher than that of common lead has been put beyond reasonable doubt. Practically simultaneously with .the first announcement of these results for thorium lead, a series of investigations were published on the atomic weight of lead from uranium minerals, by T. W. Richards and collaborators at Harvard, Maurice Curie in Paris, and Honigschmid and collaborators in Vienna, which show that the atomic weight is lower than that of ordinary lead. The lowest result hitherto obtained is 206 * 046, by Honigschmid and Mile. Horovitz for the lead from the very pure crystallised pitchblende from Morogoro (German East Africa), whilst Richards and Wadsworth obtained 206-085 for a carefully selected specimen of Norwegian clevite. Numerous other results have been obtained, as, for example, 206*405 for lead from Joachimsthal pitchblende, 206*82 for lead from Ceylon thorianite, 207*08 for lead from monazite, the two latter being mixed uranium and thorium minerals. But the essential proportion between the two elements has not, unfortunately, been determined. Richards and Wadsworth have also examined the density of their uranium lead. In every case they have been able to confirm the conclusion that the atomic volume of isotopes is constant, the uranium lead being as much lighter as its atomic weight is smaller than common lead. Many careful investigations of the spectra of these varieties of lead show that the spectrum is absolutely the same so far as can be seen. Thorium and Ionium. A second quite independent case of a difference in atomic weight between isotopes has been established. It concerns the isotopes thorium and ionium, and it is connected in an important way with the researches which, on two previous occasions, I have given an account of here, the researches on the growth of radium from uranium, which have been in progress now for fourteen years. It is the intervention of ionium and its very long period of life which has 1917] on The Complexity of the Chemical Elements 1^51 made the experimental proof of the production of radium from uranium such a long piece of work. Previously only negative results were available. One could only say, from the smallness of the expected growth of radium, that the period of average life of ionium must be at least 100,(M)(> years, forty times longer than that of radium, and, therefore, that there must be at least forty times as much ionium by weight as radium in uranium mmerals, or at least 13 "(i grams per iboo kilos, of uranium. Since then further measurements, carried out by Miss Hitchins last year, have shown definitely for the first time a clear growth of radium from uranium in the largest prepara- tion, containing 3 kilos, of uranium, and this growth, as theory requires, is proceeding according to the square of the time. In three years it amounted to 2 x 10" " grams of radium, and in six years to just four times this quantity. From this result it was concluded that the l^revious estimate of 100,000 years for the period of ionium, though still of the nature of a minimum rather than a maximum, was very near to the actual period. Joachimsthal pitchblende, the Austrian source of radium, contains only an infinitesimal proportion of thorium. An ionium preparation separated, by Auer von AVelsbach, from 30 tons of this mineral, since no thorium was added during the process, was an extremely concentrated ionium preparation. The atomic weight of ionium — • calculated by adding to the atomic weight of its product, radium, four for the a-particle expelled in the change — is 230, whereas that of thorium, its isotope, is slightly above 232. The question was whether the ionium-thorium preparation would contain enough ionium to show the difference. Honigschmid and Mile. Horovitz have made a special examination of the point, first redetermining as accurately as possible the atomic weight of thorium and then that of the thorium-ionium preparation from pitchblende. They found 232*12 for the atomic weight of thorium, and by the same method 231*51 for that of the ionium-thorium. A very careful and complete examination of the spectra of the two materials showed for both absolutely the same spectrum and a complete absence of impurities. If the atomic weight of ionium is 230, the ionium- thorium pre- paration must, from its atomic weight, contain 30 per cent of ionium and 70 per cent of thorium by weight. Professor Meyer has made a comparison of the number of a-particles given per second by this preparation with that given by pure radium, and found it to be in the ratio of 1 to 200. If 30 per cent is ionium, the activity of pure ionium would be one-sixtieth of that of pure radium, its period some sixty times greater, or 150,000 years. This confirms in a very satis- factory manner our direct estimate of 100,000 years as a minimum, and incidentally raises rather an interesting question. My direct estimate involves directly the period of uranium itself, and if the value accepted for this is too high, that for the ionium will be correspondingly too low. Now, last week. Professor Joly was K 2 132 Professor Frederick Soddy [May 18, bringing before you, I belieye, some of his exceedingly interesting work on pleochroic balos, from which he has grounds for the conchi- sion that the accepted period of uranium may be too long. But since I obtained, for the period of ionium, a minimum valae two- thirds of that estimated by Meyer from the atomic weight, it is difficult to belieye that the accepted period of uranium can haye been oyerestimated by more than 50 per cent of the real period. The matter could be pushed to a further conclusion if it were found possible to estimate the percentage of thorium in the thorium-ionium preparation, a piece of work that ought not to be beyond the resources of radio-chemical analysis. This would then constitute a check on the period of uranium as w^ell as on that of ionium. Such a direct check would be of considerable importance in the determination of geological ages. The period of ionium enables us to calculate the ratio, between the weights of ionium and uranium in pitchblende, as 17 "4 to 10^, and the doctrine of the non- separability of isotopes leads directly to the ratio, between the thorium and uranium in the mineral, as 41*7 to 10^ This quantity of thorium is, unfortunately, too small for direct estimation. Otherwise it would be possible to deyise a yery strict test of the degree of non-separability. As it is, the work is sufficiently convincing. Thirty tons of a mineral containing a majority of the known elements in detectable amount, in the hands of one whose researches in the most difficult field of chemical separation are world-renowned, yield a preparation of the order of one-millionth of the weight of the mineral, which cannot be distin- guished from pure thorium in its chemical character. Anyone could tell in the dark that it was not pure thorium, for its a-actiyity is 30,000 times greater than that of thorium. This is then submitted to that particular series of purifications designed to give the purest possible thorium for an atomic weight determination, and it emerges without any separation of the ionium, luit with a spectrum identical with that of a control specimen of thorium similarly purified. The complete absence of impurities in the spectrum show that the chemical work has been yery effectiyely done, and the atomic weight shows that it must contain 3o per cent by weight of the isotope ionium, a result which agrees with its a-activity and the now known period of the latter. Determinatiox of Atomic AYeights. The results enumerated thus prove that the atomic weight can no longer be regarded as a natural constant, or the chemically pure element as a homogeneous type of matter. The latter may be, and doubtless often is, a mixture of isotopes varying in atomic weight over a small number of units, and the former then has no exact physical significance, being a mean value in which the proportions of 1917] on The Complexity of the Chemical Elements 133 the mixture as well as the separate atomic weights are both unknown. New ideals emerge and old ones are resuscitated bv this develop- ment. There may be after all a very simple numerical relation between the true atomic weights. The view that seems most pro- bably true at present is that while hydrogen and helium may be the ultimate constituents of matter in the Proutian sense, and the atomic weights therefore approximate multiples of that of hydrogen, small deviations, such as exist between the atomic weights of these two constituent elements themselves, may be due to the manner in which the atom is constituted, in accordance with the principle of mutual electro-magnetic mass, developed by Silberstein and others. The electro -magnetic mass of two charges in juxtaposition would not be the exact sum of the masses when the claarges are separated. The atomic w'eight of hydrogen is 1'0(»78 in terms of that of helium as 3*1)9, and that the latter is not exactly four times the former may be the expression of this effect. Harkins and Wilson have recently gone into the question with some thoroughness, and the conclusion of most interest in the present connection, which appears to emerge, is in favour of regarding most of the effect to occur in the formation of helium from hydrogen, and very little in subsequent aggregations of the helium. In the region of the radio-elements, where we have abundant examples of the expulsion of helium atoms as a-particles, it seems as if we could almost safely neglect this effect altogether. Thus radium has the atomic weight almost exactly 226, and the ultimate product almost exactly 2o6, showing that in 5 a- and 4 /5-ray changes the mean effect is nil, and the atomic weights are moreover integers in terms of oxygen as 16, or helium 4. It is true that the atomic weights of both thorium and uranium are between U • 1 and 0 • 2 greater than exact integers, but it is difficult to be sure that this difference is real. When, among the light elements, we come across a clear case of large departure from the integral value, such as magnesium 24*32 and chlorine 35 "46, we may reasonably suspect the elements to be a mixture of isotopes. If this is true for chlorine, it suggests a most undesirable feature in the modern practice of determining atomic weights. More and more the one method has come to be relied upon : the preparation of the chloride of the element and the com- parison of its w^eight with that of the silver necessary to combine with the chlorine, and with the weight of the silver chloride formed. Almost the only practical method, and that a very laborious and imperfect one, which may be expected to resolve a mixture of isotopes, is by long-continued fractional gaseous diffusion, which is likely to be the more effective the lower the atomic weight. Assume, for example, chlorine were a mixture of isotopes of separat'^. atomic weights 34 and 36, or 35 and 36. The 34 isotope would diffuse some 3 per cent faster than the 36, and the 35 some 1*5 per cent faster. 134 Professor Frederick Soddy [May 18, The determination of the atomic weight of chlorine in terms of that of silver has reached now such a pitch of refinement that it shonld be able to detect a difference in the end fractions of the atomic weight of chlorine, if chlorine or hydrogen chloride were systemati- cally subjected to diffusion. It is extremely desirable that such a test of the homogeneity of this gas should be made in this way. Clearly a change must come in this class of work. It is not of much use starting with stuff out of a bottle lal)elled " purissimum " or " garantirt," and in determining to the highest possible degree of accuracy the atomic weight of an element of unknown origin. The great pioneers in the subject, like Berzelius, were masters of the whole domain of inorganic chemistry, and knew the sources of the elements in Nature first-hand. Their successors must revert to their practice and go direct to Nature for their materials, must select them carefully with due regard to what geology teaches as to their age and history, and, before carrying out a single determination, they must analyse their actual raw materials completely, and know exactly what it is they are dealing with. Much of the work on the atomic weight of lead from mixed minerals is useless, for failure to do this. They must rely more on the agreement, or disagreement, of a great variety of results by methods as different and for materials as different as possible, rather than on the result of a single method pushed to the limit of refinement, for an element provisionally purified by a dealer from quite unknown materials. The precon- ceived notion, that the results must necessarily agree if the work is well done, must he replaced by a system of co-operation between the workers of the world checking each other's results for the same material. A year ago anyone bold enough to publish atomic weight determinations, which were not up to the modern standards of agreement among themselves, would have been regarded as having mistaken his vocation. If these wider ideals are pursued, all the labour that has been lavished in this field, and which now seems to have been so largely wasted, may possibly bear fruit, and where the newer methods fail, far below the narrow belt of elements which it is possiljle to watch changing, the atomic weight worker may be able to pick up the threads of the great story. No doubt it is writ in full in the natural records preserved by rock and mineral, and the evidence of the atomic weights may be able to carry to a triumphant conclusion the course of elementary evolution, of which as yet only an isolated chapter has been deciphered. The Structure of the Atom. The third line of recent advance, which does much to explain the meaning of the isotopes and the Periodic Law, starts from Sir Ernest Rutherford's nuclear theory of the atom, which is an attempt to determine the nature of atomic structure, which again is 1917] on The Complexity of the Chemical Elements 135 the necessary preliminary to the nnderstandiiig of the third aspect in which the elements are or may be complex. That uranium and thorium are built up of different isotopes of lead, helium and electrons is now an experimental fact, since they have been proved to change into these constituents. But the questions how they are built up, and what is the nature of the non-radioactive elements, which do not undergo changes, remain unsolved. Professor Bragg showed in 1905 that the ^-particles can traverse the atoms of matter in their path almost as though they were not there. As far as he could tell, and the statement is still true of the vast majority of a-particles colhding with the atoms of matter, the a-particle ploughs its way straight through, pursuing a practically rectilinear course, losing slightly in kinetic energy at each encounter with an atom, until its velocity is reduced to the point at which it can no longer be detected. From that time, the rt-particle became as it were, a messenger that could penetrate the atom, traverse regions which hitherto had been bolted and barred from human curiosity, and on re-emerging could be questioned, as it was questioned, effectively by Rutherford, with regard to what was inside. Sir J. J. Thomson, using the electron as the messenger, had obtained valuable information as to the number of electrons in the atom, but the massive material a-particle alone can disclose the material atom. It was found that, though the vast majority of a-particles re-emerge, from their encounters with the atoms, practically in the same direc- tion as they started, suffering only slight hither and thither scattering due to their collisions with the electrons in the atom, a minute proportion of them suffer very large and abrupt changes of direction. Some are swung round, emerging in the opposite to their original direction. The vast majority, that get through all but undeflected, have met nothing in their passage save electrons, 8000 times lighter than themselves. The few, that are violently swung out of their course, must have been in collision with an exceedingly massive nucleus in the atom, occupying only an insignificant fraction of its total volume. The atomic volume is the total volume swept out by systems of electrons in orbits of revolution round the nucleus, and beyond these rings or shells guarding the nucleus it is ordinarily impossiljle to penetrate. The nucleus is regarded by Rutherford as carrying a single concentrated positive charge, equal and opposite to that of the sum of the electrons. Chemical phenomena deal almost certainly with the outermost system of detachable or valency electrons alone, the loss or gain of which conditions chemical combining power. Light spectra originate probably in the same region, though possibly more systems of electrons than the outermost may contribute, while the X-rays and y-rays seem to take their rise in a deep-seated ring or shell around the nucleus. But mass phenomena, all but an insignificant fraction, originate in the nucleus. 136 Professor Frederick Soddy [May 18, In the original electrical theory of matter, the whole mass of the atom was attributed to electrons, of which there would have been required nearly 2000 times the atomic weight in terms of hydrogen as unity. With the more definite determination of this number, and the realisation that there were only about half as many as the number representing the atomic weight, it was clear that all but an insignifi- cant fraction of the mass of the atom was accounted for. In the nuclear hypothesis this mass is concentrated in the exceedingly minute nucleus. The electro-magnetic theory of inertia accounts for the greater mass if the positive charges that make up the nucleus are very much more concentrated than the negative charges which constitute the separate electrons. The experiments on scattering clearly indicated the existence of such a concentrated central positive charge or nucleus. The mathematical consideration of the results of a-ray scattering, obtained for a large number of different elements, and for different velocities of a-ray, gave further evidence that the number of electrons, and therefore the + charge on the nucleus, is about half the number representing the atomic weight. But van der Broek, reviving an isolated suggestion from a former paper full of suggestions on the Periodic Law, which were, I think, in every other respect at fault, suggested that closer agreement with the theory would be obtained if the number of electrons in the atom, or the nuclear charge, was the number of the place the element occupied in the Periodic Table. This is now called the atomic number, that of hydrogen being taken as 1, helium 2, lithium :^, and so on to the end of the table, uranium 92, as we now know. For the light elements, it is practically half the atomic weight ; for the heavy elements, rather less than half. I pointed out this accorded well with the law of radioactive change that had been established to hold over the last thirteen places in the Periodic Table. This law might be expressed as follows : The expulsion of the a-particle carrying two positive charges lowers the atomic number Ijy two, while the expulsion of the yS-particle, carrying a single negative charge, increases it by one. In ignorance of van der Brock's original suggestion, I had, in representing the generalisation, shown the last thirteen places as differing by unit by unit in the number of electrons in the atom. Then followed Moseley's all-embracing advance, showing how from the wave-lengths of the X-rays, characteristic of the elements, this conception explained the whole Periodic Taljle. The square roots of the frequency of the cliaracteristic X-rays are proportional to the atomic numbers. The total number of elements existing betweeen uranium and hydrogen could thus be determined, and it was found to be ninety-two, only five of the places being vacant. The " exceptions " to the Periodic Law, such as argon and potassium, nickel and cobalt, tellurium and iodine, in which an element with higher atomic weight precedes instead of succeeds one with lower, was confirmed by the 1917] on The Complexity of the Chemical Elements 137 determination of the atomic numbers in every case. From now on, this number, which represents the + charg-e on the nucleus, rather than the atomic weight, becomes the natural constant which deter- mines chemical character, light and X-ray spectra, and, in fact, all the properties of matter, except those that depend directly on the nucleus — mass and weight on the one hand, and radioactive properties on the other. What, then, were the isotopes on this scheme ? Obviously they were elements with the same atomic number, the same nett charge on the nucleus, but with a differently constituted nucleus. Take the very ordinary sequence in the disintegration series, one a- and two /?-rays being successively expelled in any order. Two + and two - charges have been expelled, the nett charge of the nucleus remains the same, the chemical character and spectrum the same as that of the first parent, but the mass is reduced 4 units because a helium atom, or rather nucleus, has been expelled as an a-particle. The mass depends on the gross number of + charges in the nucleus, chemical properties on the difference between the gross numbers of + and - charges. But the radioactive properties depend not only on the gross number of charges but on the constitution of the nucleus. We can have isotopes with identity of atomic weight, as well as of chemical character, which are different in their stability and mode of breaking up. Hence we can infer that this finer degree of isotopy may also exist among the stable elements, in which case it would be completely beyond our present means to detect. But when transmutation becomes possible such a difference would Ije at once revealed. The case is not one entirely of academic interest, because it is probal)le that the reconciliation of the conflicting views of the geolo- gists and chemists, who concluded that lead was not the ultimate product of thorium, and those who by atomic weight demonstrations on the lead have shown that it is, depends probably on this point. As has long been known, thorium-C, an isotope of bismuth, disin- tegrates dually. For 35 per cent of the atoms disintegrating, an a-ray is expelled followed by a /?-ray. For the remaining G5 per cent the /5-ray is first expelled and is followed by the a-ray. The two products are both isotopes of lead, and both have the same atomic weight, but they are not the same. More energy is expelled in the changes of the 65 per cent fraction than in those of the 35 per cent. Unless they are both completely stable a difference of period of change is to be anticipated. The same thing is true for radium-C, but here all but a very minute proportion of the atoms disintegrating follow the mode fol- lowed by the 65 per cent in the case of thorium-C. The product in this case, radium-D, which, of course, is also an isotope of lead, with atomic weight 210, is not permanently stable, though it has a fairly long period, 24 years. The other product is not known to change 138 Professor Frederick Soddy [May 18, further, but then, even if it did, it is in such small quantity that it is doubtful whether the change would have been detected. "^ But, so far as is known, it forms a stable isotope of lead of atomic weight 210. formed in the proportion of only 0*03 per cent of the whole. Xow the atomic weight evidence merely shows ttiat one of the two isotopes of lead formed from thorium is stable enough to accu- mulate over geological epochs, and it does not necessarily follow that both are. Dr. Arthur Holmes has pointed out to me that the analysis I gave of the Ceylon thorite leads to a curiously anomalous value for the age of the mineral. The quantity of thorium lead per gram of thorium is 0'0062, and this, divided by the rate at which the lead is being produced, 4*72 x 10"^^ gram of lead per gram of thorium per year, gives the age as 131 million years. But a Ceylon pitchblende, with uranium 72-88 percent and lead 4-65 per cent, and ratio of lead to uranium as 0'064, gives the age as 512 million years. Dr. Holmes regards the two minerals as likely to be of the same age, and the pitchblende to be, of all the Ceylon results, the one most trustworthy for age measurement. If we suppose that, as in the case of radium-D, the 65 per cent isotope of lead derived from thorium is not stable, and that only the 35 per cent isotope accumulates, the age of the mineral would be 375 million years, which the geologists are likely to consider much more nearly the truth. But the most interesting point is that, if we take the atomic weight of the lead isotope derived from uranium as 206 • 0, and that derived from thorium as 208 • 0, and calculate the atomic weight of the lead in Ceylon thorite, assuming it to consist entirely of uranium lead and of only the 35 per cent isotope from thorium, we get the value 207 '74, which is exactly what I found from the density, and what Prof. Honigschmid determined (207*77). The question remains, if this is what occurs, what does this unstable lead change into ? If an a-particle were expelled mercury would result, or if a /5-particle bismuth, two elements of which I could find no trace in the lead group separated from the whole 20 kilos, of mineral. But if an a- and a y8-particle were both ex- pelled, the product would l)e thallium, which is present in amount small but sufficient for chemical as well as spectroscopic characterisa- tion. If the process of disintegration does proceed as suggested, it should be possible to trace it, for this particular lead should give a feeble specific a- or y8-radiation, in addition, of course, to that due to other lead isotopes. So far it has not been possible to test this. In the meantime, the explanation offered is put forward provisionally as being consistent with all the known evidence. Looking for a moment in conclusion at the broader aspects of the new ideas of atomic structure, it seems that though a sound basis for further development has been roughed out, almost all the detail remains to be supplied. We have got to know the nucleus, but beyond the fact that it is constituted, in heavy atoms, of nuclei of 1917] on The Complexity of the Chemical Elements 139 helium and electrons, nothing is known. Whilst as regards the separate shells or rings of electrons which neutralise its charge and are supposed to surround it, like the shells of an onion, we really know nothing yet at all. The original explanation, in terms of the electron, of the periodicity of properties displayed by the elements, still remains all that has been attempted. We may suppose, as we pass through the successive elements in the table, one more electron is added to the outermost ring for each unit increase in the charge on the nucleus, or atomic number, and that when a certain number, 8 in the early part of the table, IS later, a complete new stable shell or ring forms, which no longer participates directly in the chemical activities of the atom. Thanks, however, to Moseley's work, this now is not sufficiently precise ; for we know the exact number of the elements, and the various atomic numbers at which the remark- able changes, in the nature of the periodicity displayed, occur. Any real knowledge in this held will account not only for the two short initial periods, but also for the curious double periodicity later on, in which the abrupt changes of properties in the neighbourhood of the zero family alternate with the gradual changes in the neigh- bourhood of the Vlllth groups. The extraordinary exception to the principle of the whole scheme presented by the rare-earth elements remains a complete enigma, none the less impressive because, beyond them again in the table, the normal course is resumed and continues to the end. [F. S.] WEEKLY EVENIXa MEETING, Friday, May 25, 1917. Sir James Crichtox-Browne, J.P. M.D. LL.I). F.R.S. Treasurer and Vice-President, in the Chair. J. Barcroft, M.A. F.Pi.S. Breath lessness. I No Abstract.] 140 Mr. J. H. Balfour Browne [June 1, WEEKLY EVENING MEETING. Friday, June 1, 1917. His Grace The Duke of Northumberland, K.G. P.O. D.C.L. F.R.S., President, in the Chair. J. H. Balfour Browne, K.C. D.L. J.P. LL.l). M.E.I. The Brontes: A Hundred Years After. It is one hundred and one years since Charlotte Bronte was born at Thornton, and ninety-nine years since Emily Bronte was born, and perhaps it is not improper to look upon this year as a sort of centenary of both these remarkable women. There is a "close season" for the dead, and daring that period, after the grave has closed upon them, even Calumny shuts its mouth, and to some extent Truth also is muzzled, out of respect to the feelings of the living. It was under this disability — writing in that "close season" — that Mrs. Gaskell achieved her admirable " Life of Charlotte Bronte," which, even with its defects, is perhaps the most readable biography in the language — a biography of which Thackeray said that it " was necessarily incomplete, though most touching and admirable." It was burdened by the same restrictions that Sir AVemyss Reid compiled, with the assistance of more of the many letters of Charlotte Bronte, his excellent " Monograph," which was published in 1877. Indeed, Sir Wemyss Reid, writing to me after the publication of his book, said he had been accused of " not telling the whole truth about Charlotte's residence in Brussels," and added, " But how could I, whilst her husband still lives, and favours me with an occasional letter of a by no means amicable kind." But now, after these sixty years, it is easier to speak the whole truth than it w^as then, and even to point to errors which have been made by writers of "lives" in their painstaking but "necessarily incomplete " records of the Brontes. There is one curious circumstance to be noted in connexion with the Bronte literature, and that is, that in the case — especially of Charlotte — of writing many books there is no end. Biographies, "Monographs," "Notes," "Circles" and "Mysteries" load the shelves of our libraries, and the curious tiling is that all these have been devoted to recording and explaining the life of the most auto- biographical of all our novelists. Of course any writer of fiction is, 1917] on The Brontes: A Hundred Years After 141 even when pretending to write about the lives of others, making certain confessions as to his own thoughts and feelings, and every writer must transcribe from the pages of his or her experience. It is no surprise to us to learn that the wings of imagination are no use without the feet of experience. But very few writers have made such literal transcripts from her own past as Charlotte Bronte. Many of her pages read like a diary. Everyone, from the very first, has recognized, in " Jane Eyre " and " Yillette " especially, works of great fiction, but also of intimate biographical confession. Charlotte Bronte, in writing to her life- long friend, Ellen Nussey, says, " Thou hast an honest soul as ever animated human carcase, and a clean one, for it is not ashamed of showing its inmost recesses — only be careful with whom you are frank." It is true of Charlotte herself that she was not ashamed of showing the inmost recesses of her fiery heart — and it is in that that her merit lies — but she was " frank " with the public, and wrote down not only her own painful history but her most secret feelings in these great confessions of her books. But although it would seem by thus "making," in the old phrase, "a clean breast of it," she had really left nothing for those who essayed her biography to do, it is this very candour which has apparently been the cause of all this vehement literature which has been devoted to her, and to those who were associated with her. Beginning with the spite of the " Quarterly " Reviewer, who said of the author of " Jane Eyre " that she was *' evidently a woman who had long forfeited the society of her own sex " (it was only a woman that could have written that calumny), the memories of these women — Charlotte, " the fiery-hearted vestal of Haworth," according to Swinburne, and Emily, the strongest writer of fiction of the century — have been tormented by works of criticism. It was this quality of literal candour in Charlotte Bronte's books which made them not only literature but conundrums. The critics and the public were not only interested in the story, they were delighted in the search for the various persons who had sat in Charlotte's studio for such vivid portraiture. But her works were not only a small portrait gallery — they were a gazetteer. All the places which are mentioned in them were identified. Lowood was Cowan Bridge School ; Oakwell Hall was the Field- head in "Shirley" ; Yillette was Brussels ; and so on. Indeed, you cannot turn a page but you are in some place which has been identified, or in the presence of someone who had a real existence and was the model for her sometimes too literal sketch. Mr. Brockle- hurst was Mr. Cams Wilson ; M. Pelet (in " The Professor "), Rochester ; Robert Moore and Paul Emanuel were, according to some, all drawn from M. Heger. Again, Jane Eyre, Caroline Helston and Lucy Suowe were, according to those amateur detectives. 142 Mr. J. H. Balfour Browne [June 1, Charlotte herself ; Madame Beck was Madame Heger ; Emily Bronte was Shirley Keeldar ; Dr. John was Mr. George Smith, one of her publisher's firm ; and St. John Rivers was Henry Nussey. The Mr. Macarthy, with his "steady going clerical faults" mentioned at the end of '* Shirley " as the successor of the " rampant boistrous " Mr. Malone, is Mr. A. Nichols, who was afterwards her husband. It was these guesses which delighted the readers who have a keen scent for scandal, and some of them were good guesses — indeed, in some cases the portraiture is so exact that none with eyes could miss the likeness. Much of the literature about Charlotte Bronte has been occupied with this identification of the bodies of the dead, and it has been quite a surprise to some that Charlotte does not seem to have got others that she knew, like Mrs. Gaskell, Harriet Martineau, Sir D. K. Shuttle worth and Thackeray in her Tussaud Waxworks, and even some of them in the Chamber of Horrors with Mr. Brocklehurst and Madame Beck.* So far has this process been carried, not without excuse in the case of Charlotte, that some have applied the same inquisition to the pages of " Wuthering Heights " ; and one writer, of some ability, has found M. Heger again in Heathcliff, and the ravings of Cathy in the distemper of Charlotte Bronte after her very wise return from Brussels. This dissection — for the vivisection which had to be done in the time of Mrs. Gaskell has ceased, and we are now only in a kind of Morgue — has been carried too far. It is not really literary criticism at all, but a spurious kind of silly curiosity. Every writer has to draw, not for inspiration but for facts, on their experiences, and every writer has, like the spider, to make his web by means of his spinneret out of his own inner being. In this way every book, however fictional, if it is great, is history and biography, and in every work the writer writes himself down on every page. Many have no need, as Dogberry had, of the " AVatch," whom he asked to *' Write me down an ass ! " They can do that for themselves ! * But not only that the critics found that all the characters in her books can be identified with persons then living, they have in their indefatigable researches denied to her the credit of inventing the plots of her stories. Mrs. Gaskell tells whsbt happened in Charlotte's youth in the neighbourhood of Leeds. "A young lady, who held the situation of a governess, had been wooed and married by a gentleman holding some subordinate position in the commercial firm to which the young lady's employer belonged. A year after her marriage, during which she had given birth to a child, it was discovered that he whom she called her husband had another wife, lieport now says that the first wife was deranged, and that he had made this an excuse to himself for his subsequent marriage." But Professor Jack, of the University of Aberdeen, writing in " The Cambridge History of English Literature," has found almost the whole Jane Eyre story in a tale by J. Sheridan Le Fanu in the " Dublin University Magazine " of 1839. There you have the wife that was no wife, the attempt to murder, and all the rest of it. 1917] on The Brontes: A Hundred Years After 143 Enough has been written about Charlotte and Emily Bronte's youth and the drab surroundings of the dull days of their girlhood. Haworth village, which clambers up the hill to the moors, and the moors themselves are well known to every, even casual, student. The bare facts of their uneventful lives in the staring parsonage, surrounded on three sides by graves, are exceedingly simple. The father, Patrick Bronte, was an ambitious Irishman, born in County Down, where at sixteen he became a schoolmaster when really he could have had very little to teach ; but ignorance is a fact that never deters instructors. But having taught Irish boys for five years, he went to Cam- bridge, then into the Church ; had a curacy in Essex, where he had his first love affair, which, like many that are tried with a " prentice hand," did not prosper. After that he was a curate in Shropshire, at Dewsbury, incumbent of Hartshead in Yorkshire, wrote some poems that were not poetry, became Vicar of Thornton, where he married, and where he afterwards speaks of having been happy, and from this he went to Haworth with his family, an ailing wife, six weird children, and his belongings, in seven carts, in 1820. Here through his eccentric days he remained nntil he died in 186 1. He was not in any way remarkable, although he was a good deal out of the common. His conduct as a clergyman may have been excellent. His principles may have been as pure and as stiff as the starched white neck-cloth which made a rampart about his throat and chin, but he was as bleak in his character as Haworth Moor. His eccen- tricities leaned to madness side. Finding that Tabby had put out some boots to warm at the fire, for the shoes of the little mites who had been out on the moor in the rain had got wet, he burned them, tliat the children might not be pampered by what the Yorkshire people call " changing their feet." He cut up into shreds his wife's one piece of finery — a dress which had been given her — and which, although it was too fine to wear, was often looked at with a pleased gleam of satisfaction. He stuffed the hearth-rug up the chimney, and was properly nearly choked by the pungent smoke. He took his meals alone, and after the death of his gentle timid wife, of cancer, he left the children to themselves to build castles in the grim and nipping Yorkshire air, or sent them to starve at the Cowan Bridge School. He carried a pistol about with him for self-defence, but used to discharge it at a harmless barn door when his feelings required something more than ordinary articulate expression. A sort of swearing by deputy. There was nothing very admirable, nothing very remarkable, nothing very lovable about the dour old man. He was like good timber which had been warped in the drying, and as far as his religion went it was more of what the Scotch call " a bee in his bonnet " than the adventure of a soul. His wife. Miss Branwell of Penzance, was estimable as a weak gentlewoman, who had the heart-ability to discern something to love 144 Mr. J. H. Balfour Browne [June 1, and respect in her irascible husband, and died when her Httle children ^Yere too young to know a mother's love. Her sister came to Haworth to mother or stepmother his children after Mrs. Bronte's death. She never took kindly to the austere Yorkshire home to which she came, and her aging spinster thoughts seem to have been much with Cornwall. Anne Bronte must have taken after her mother, and never had any of the wild-fire of her father in her. She was a gentle, almost pretty, woman. She, like her more famous sisters, WTote. She wrote two novels which are not very praiseworthy — they were written out of the penury of her experiences. "Agnes Grey" was a small canto in the Odyssey of the Governess, to which Charlotte made more notable contributions ; and "The Tenant of AVildfell Hall," which was a novel with a purpose, and was informed with a good deal of her own bitter home experiences of a brother who had been spoiled by his father and his sisters, and was spoiled far more by himself. Her books do not really repay the reading of them, and she died sadly enough with the family disease of " home sickness " as an inter- current phase of her consumption, strong upon her, at Scarborough, in a shy May of 1849. She was, we may say, a "sweet woman," but we generally say that when there is nothing else to be said. Her poems are pious and prosy, but I believe some of them survive as lugul)rious hymns. Of Branwell Bronte, the son, it is difficult to speak with the patience that his father seems to have suffered him. He had talent, and succeeded in nothing he put his unsteady hand to. He was going to be an artist, but seems to have had none of the gifts which would have carried him to success in that direction. He was an unsatisfactory railway booking clerk, and as private tutor he achieved disgrace. The originality of his death — if it is true that he stood up to face death and died on his feet — is dramatic, but it is too theatrical to impress one with admiration of a youth who was content to be the boon-companion of chance guests at the " Black Bull " — the pot-house in the viUage— where it is supposed he seasoned poor liquor with better wit. He had a reputation amongst those who found pleasant social intercourse at funeral feasts, or " arvills," but as for the proofs of the genius he was credited with by his sisters, they are not to be found. His letter to AVordswortb, which has been preserved by Mrs. Gaskell, is clever and bumptious, but the verses he sent with it, which have also been preserved, are trash. That he was a Imi'den in this liumdrum parsonage we can well beheve, but that his sottishness or opium- eating and disgrace was the cause of Charlotte Bronte's two years of suffering and sorrow after her return from Brussels, as Mrs. Gaskell would have us believe, is for those who look at the evidence far from the true verdict. Just as their father had been a teacher, there was nothing for it but that all the three girls should be governesses ; but they all nourished the aml)ition to rise to the proud position of keeping a 1917] on The Brontes: A Hundred Years After 145 school ! Of Emily's life aucl Anne's there is, so far as then- doings are concerned, nothing more to say. They were sent to a school, where they were half -starved. They had to walk two miles — perishing cold miles in winter — to church to hear Mr. Brocklelmrst (I l)eg his pardon, Mr. Carus Wilson) preach. Then there was an epidemic of fever, and no wonder, if it is true, as Sir AVemyss Reid says, that " during the whole time of their sojourn there the young Brontes scarcely ever knew what it was to be free from the pangs of hunger." It was there, too, that the poor little girls had their hair cropped and wore night-caps, but " where pocket handkerchiefs did not appear in the list of clothing." At home at Ha worth they had no children friends, and depended upon one another for all the society they had. To see the little children going out on to the moors hand-in-hand is sad enough, but it is even more melancholy to see them, when on one occasion they had been asked out, or when the village school children came to the parsonage, having to be taught to play. Taught to play ! Why they had not learned one of the best lessons life has to teach. Even when Charlotte went to Miss Wooler's school at Roehead she could not play ball with the other girls, but stood about while they played, with the near short-sighted companionship of a book. But they were good little creatures, as quiet as a mouse in the house, and we hear of Maria, when she was about eight, shutting herself up in the study (which had no fireplace) with a newspaper, and reading it all so well that she could even tell you what was in the Parliamentary debates — which is poor food even for a strong stomach, but for a child of eight it is a porridge of sand and straw. There was too much of these PoHtics and too little of " Nuts and May " in theii little lives. AYhen Charlotte became a pupil at Roehead, while they found that she had never learned grammar and very little geography, she knew the names of two ministries, which must have been a puzzle even then, and would be worse in our time of Coalition and National Cabinets. But this isolation of the children accounted for a great deal. A few impressions, like a sharp knife, cut deep. It is the many impressions, which come and go to those more in the world than these little recluses of Haworth, that leave the mind with nothing but scratches on memory. Affections, too, cannot both be wide and deep. If you spread your heart in gold-beater's leaf over many people, the result is acquaintanceship. If you give it to a few it is love ! It was thus that the affectionate ties of the Bronte family were as strong as steel. It was thus, too, that Charlotte Bronte, when she did really love someone outside the home circle, loved with an intensity of passion which thrilled her " to the finest fibre of her nature." We may have pity for this grim ordeal of the mites, but we must recognize that this haggard human life was the school which was training the women who were to write such great romances as " Jane Evre " and " Wuthering Heights." Vol. XXII. (No. Ill) L 146 Mr. J. H. Balfour Browne [June 1, Thej were too old for their age, too wise for their years, and began to write and act little plays when they should have been romping. Their games, if they could be called games, were poor imitations of the pastimes of the old and effete, rather than the great games of exuberant childhood. But these hard experiences had the effect of making them shy and reserved with strangers. Ciiarlotte had women friends, but they were rather satellites than equals — Ellen Nussey, Mary Taylor and Margaret Wooler, were life- long worshippers of hers. They shine in her light. She wrote hundreds of letters to Miss Nussey which, although written for private eyes, have been spread out by enterprising biographers before the public. But Charlotte, notwithstanding these companionships, was always a sad and subdued woman — except in the home circle. With strangers she was shrinking and shy, as an untamed squirrel. When she was visiting Mrs. Gaskell at Manchester a Mr. Potter called. Mrs. Gaskell rose to welcome him, and turned round to the chair near the window to present Charlotte Bronte to him. She was surprised to find the chair empty, and she thought Charlotte had escaped through the door into the dining-room. When Mr. Potter left Charlotte appeared from behind the heavy curtain which hung from the window, and explained that she " wasn't able to face a stranger." And yet that was after she was a famous writer of books. But her aloofness was nothing to that of Emily. She doesn't seem to have had any women friends, and no men lovers. She was as lonely as a great Alp ! But, after all, is not that one of the dooms of greatness, that it cannot find its mate ? Are not some great spirits severed from friends by the austerity of their genius, and condemned to the solitary cell of their own great imaginings ? Now, it is strange, in relation to Charlotte Bronte, that she should have made one of the fullest confessions of the most secret heart- matters that was ever made by the pen of a Avomen. In her books she not only " stands and unfolds herself," but as we have seen, every place where she has been, most of the persons she has met, are in this her show. That she courted seclusion, and yet should let the public into the closet of her heart, is a very strange fact in literary history. It is, as I said, partly because of the fact that her pictures are veritable bits of domestic history — that the people in them are real people ; the actual schools and private houses are the "- properties " of her theatre — that she has attained a publicity and secured an interest which is not given to ordinary imaginative literature, and which is withheld from Emily Bronte's more remark- able book. It is because of this characteristic of Charlotte Bronte's books that they have been the centre of a storm of criticism. She has had ardent admirers and angry readers. Her portraiture was often too true to be pleasant. Often she was scathingly unjust, as 1917] on The Brontes: A Hundred Years After 147 in her portrait of Madame Beck, if, as we are compelled to Ijelieve, that was a likeness of ^ladame Heger. Charlotte Bronte's letters have tramped through auction rooms, even a pitiful wisp of hair has been sold at an auction, there are stacks of her correspondence at the British Museum, and there is scarcely a fact in her private timid life that has not been exposed. We are even told, with the trivial minuteness of those who pride themselves on irrelevant details, that she made a chemise when she was five years of age. All this lime-light business would have been very distasteful to a woman with such sensitive modesty as the writer of these masterful books. But she herself has pulled the string of this shower-bath of words and criticisms, and she caunot complain of the douche. But if, as I have said, their childhood was sad, if they were isolated on those moors, if all their games were lessons, and if they never were the wholesome laughing children they ought to have been, their womanhood was equally depressing and uncomfortable. It requires a saint or a mother to be a good governess. The only one of them to come near saintliness was Anne, and she succeeded better in that vocation than the other two. But motherliness was not in Charlotte Bronte's nature, or, as far as we am make out, in Emily's. The latter Hked dogs better than children. It is certain Charlotte never took to children, and there are no real nursery children in her books — nursery children who begin to lose their wings when they begin to feel their feet.* But this want of motherliness in Charlotte Bronte's books — who was a good house-mother at home — is a distinct defect in these great monuments of genius. They were great teachers of men and women, but quite poor teachers of little children. It was obvious that neither Charlotte nor Emily made ideal governesses. It is odd to note that with such a dull home as Haworth, the Bronte's were, when they were away from it, home-sick. Thus, Emily, who went as a pupil to Miss Wooler's at Roehead, when Charlotte returned there as a teacher, " became literally ill from home-sickness," and Charlotte says, " I felt in my heart she would die, if she did not go home, and with this conviction obtained her recall." Then, when after some time, Emily went as a governess to a school near Halifax, although there * Swinburne in his "Note," where he does more tban eloquent justice to Charlotte Bronte's genius, and in doing so, like an impassioned critic, has done less than justice to other great writers, has acknowledged rightly George Eliot's superior claims in this respect, and admits George Eliot's adorable fidelity in writing of children — and even mentions some of her little ones who have the charm of infancy which secures for them unquestioned immortality. That he was sometimes harsh in his critical comparisons is true. In speaking of Charlotte Bronte's work, he says it will exist "when even Daniel Deronda has gone the way of all waxworks ; when Miss Broughton no longer ' cometh up as a flower ' ; and even Mrs. Oliphant is at length ' cut down like the grass."* L 2 148 Mr. J. H. Balfour Browne [June 1, is not in existence any complaint from the young stoic, Cliarlotte writes of her residence there, " I have had one letter from her since her departm-e ; it gives an appalling account of her duties ; hard labour from six in the morning to eleven at night, with only one half-hour of exercise between them. This is slavery ; I fear she cannot stand it." She was there only six months. Governessing was a failure. But they still looked forward to the school they were to keep, and it was with a view to preparing themselves for the duties that, with pecuniary assistance from Miss Branwell, they went to school in Brussels in 1842. It is there that we are on the threshold of the drama. Before she went to Brussels Charlotte had been asked in marriage — he called it, but it was in housekeeperage — by a stick of a clergyman who was the brother of her friend, Ellen Nussey. Mrs. Gaskell has it that the proposal was " quietly declined and put aside. Matrimony did not enter into her scheme of life, but good sound earnest labour did." But that seems to me an inept observation. That she quietly put aside a wooden block. of a man who wanted a housekeeper more than a wife seems to me the result of her shrewd common sense. But no woman with a burning heart can leave matrimony out of her scheme of life ; and as for earnest labour, although she worked well, she wanted more than work, and was athirst for sympathy. I find, too, from a letter from Wemyss Reid, which he wrote to me after the publication of his " Monograph," that " as a schoolgirl, she had seen a certain Yorkshire squireen, whose name has never been mentioned by Mrs. Gaskell or myself, from whom she painted Rochester. This person had unquestion- ably attracted her fancy as a schoolgirl, but never her love." But the real experience of her life was to come to her after she had been a year in Brussels. Xow she was a woman grown, and in such a one affections can take deeper root than in a schoolgirl. And what a deep root her love for M. Heger, or Paul Emanuel, struck in her heart, can be gathered not only from " Villette," but from the remarkable letters to M. Heger, which only saw the full light — for Mrs. Gaskell only quoted a few words from them — in 1918. Well, what happened in Brussels ? She was a pupil, and afterwards a teacher, at £16 a year in Madame Heger 's pensio7inat, and that, as Sir T. AVemyss Reid tells us, was the " turning-point in her life, which changed its current and gave it a new purpose, a new meaning. She learnt much during her two years' sojourn in the Belgian capital, l)ut the greatest of all lessons she mastered while there was that self-knowledge, the taste of which is so bitter to the mouth, thongh so wholesome to the life." In a word, she fell in love with ^I. Heger, and that love, quite unsought 1)y him, unreturned l)y him, was the deepest experience of her life, and left great scars, such as are the memory of wounds, on the quick heart of this wonderful woman. 1917] on The Brontes: A Hundred Years After 149 Her marriage with Mr. Xicholls need not trouble her biographer. She was only a Avife for a few months. She does not seem to have married that gentleman — we can say it now — for love, the love of which her books and letters are full to dazzling ; but to secure a help to her eccentric old father, and for herself and her cinder of a heart, a man she could respect. Before her marriage she wrote, " I trust the demands of feeling and duty will be in some manner reconciled by the step in contemplation." " My destiny," again she writes, " will not be brilliant, certainly, but Mr. Xicholls is conscientious, affectionate, pure in heart and life. He offers a most constant and tried attachment. I am very grateful to him. I mean to try to make him happy, and papa tooy What is all this ? The first quotation about " reconciling feeling and duty," and the last, why it reads like the character of a domestic servant who is seeking a place. Still again here is an encomium, " Mr. Nicholls is a kind, considerate fellow, with all his masculine faults ; he enters into my wishes about having the thing done quietly." The thing is the marriage. This is very different from the words she, as Lucy Snowe, uses as to Paul Emanuel, " magnificent minded, grand hearted, dear, faulty little man," or again her heart speaks, " L^nknown and unloved, I held him harsh and strange — the low stature, the wiry make, the angles, the darkness, the manner, displeased me. Xow, penetrated with his influence, and living by his affection, having his worth by intellect, and his goodness by heart— I prefer him before all humanity." But she could not have said less, poor woman, of Mr. Xicholls. It reads like the description of someone who had paid a morning call, not of the marriage with your heart's desire. Even four months after her marriage she writes of her husband, " people don't compliment me as they do Arthur — excuse the name, it has grown natural to use it now." Excuse the name ! AVhy this silly diffidence ? But even later she writes of him, " He is well, thank God, and so am I, and he is ' my dear boy,' certainly — dearer now than he was six months ago. In three days we shall actually have been married that length of time." This gourd of love is of slow growth. Mr. Xicholls was doubtless all that Charlotte Bronte — we never think of her as anything else — says of him, but he has really no interest for those who love and believe in the woman he, as if by accident, married. He consoled himself after her death (the last of all the six Brontes) by a marriage with a cousin, and I cannot doubt that it was a more suitable match of mediocrities than his first ven- ture in that reckless direction. Most marriages, if they are made in Heaven, are certainly made in the dark, and a common man who marries a famous woman takes a perilous step. To borrow lustre from her fame, and to have one's private life submitted to the 150 Mr. J. H. Balfour Browne [June 1, curiositj of a gaping public must be trying for the pachydermatous self-conceit of any man. But it is not with such experiences as that, or with tlie apron- string-checked affection of Mr. George Smith (her Dr. John) that we need concern ourselves. As to Dr. John, I may say in passing that it is quite easy to believe that he was as estimable as she made him out to be ; but as Wemyss Reid told me, " Charlotte's common sense, assisted by Dr. John's mother, who dreaded the idea of such a union, came to the rescue, and she quietly put her good-looking and prosperous adorer aside." He seems, from her account, to have been a genial companion, but he was a publisher, and the payment of only £500 for the copyright of " Villette," after the success of "Jane Eyre" and "Shirley," was no doubt good business for the firm, but it naturally disappointed the author. But this, of course, was long before the Brussels days, and was, after all, a trivial episode in Charlotte Bronte's life. Emily seems to have had a heart which could love as deeply, as tragically, as her sister, but seems to have died heart-whole. Still, that for a passionate heart is the worst of diseases. ' Charlotte was certainly not heart-whole when she died, although she had got over to some extent the fracture which was the most poignant experience of her womanhood. There are few such tragedies connected with literature as this one of Charlotte Bronte's. On the background of that forbidding village on the hill-side of the grey Yorkshire moor, after her retui-n from Brussels, there was tragic pain and suffering. Deaths ! the history of the Brontes is little more than an obituary ! The vicarage at Haworth was there surrounded with hundreds of gravestones, records of hundreds of deaths. But death itself is not a tragedy. It is the futility of life which calls for tears, and there are no annals in all the range of literature of such sorrowful lives as those of the great sisters which were lived in the loneliness and seclusion of that paltry place. Of course it would be absurd to say that lives which produced "Wuthering Heights," "The Old Stoic," "Jane Eyre" and " Villette " were wasted. They were abundantly used. They have left us magnificent legacies. But although the writers have gone home, have they taken their wnges ? Xo ! Their childhood was wasted, for they never had a child's joy ; their womanhood was wasted, for their great heart stores were all in vain ; and when they might have accomplished even greater things than these remains give us, they were claimed by death, who had a mort- gage of tubercle upon their property in life. There is one curious matter to be noted in connexion with Charlotte Bronte's life and literature. No writer, as I say, has written more about herself than she has. It is not that she hns forced facts into lier service — she has made confessions like her own confession to the priest in St. (Judule in Brussels. She has un- 1917] on The Brontes: A Hundred Years After 151 packed her heart for her readers. Now after such, sometimes harrowing, candom*, it is strange to learn that she was surrounded with mystery. Mrs. Gaskell was naturally reticent about many matters, with the fine taste of an artist and the instinct of a woman. But after her came all sorts of writings. True, most of them were only gleanings in the field she had harvested. From these, however, we hear of the Brussels mystery, and even more recently we have had a book which is called the " Secret of Charlotte Bronte." The now famous Love Letters which were presented to the British Museum by Dr. Paul Heger, the son of the Dr. Heger of Charlotte's days, and which were published in the Times at the end of July 1918, were by some thought to clear up doubt and to settle questions as to the life of our novelist which had existed before that date. But even now we find there are some learned quarrels over the poor life that passed away sixty years ago, some asserting that Charlotte Bronte was in love Avith M. Heger, some that there never was anything more upon her part than admiration for a genius ; and, curiously, each of these disputants asserts that his theory is estab- lished by the letters she wrote to M. Heger in 18-44 and l'S45. Xow, the fact is there never was any mystery, and there never was any secret, and those who took the trouljle to read Mrs. Gaskell's "Life," Wemyss Reid's "Monograph," and, more important than all, what Charlotte Bronte has herself told us, have not had, could not have had, any doul)t about the plain but haggard story of the wonderful little woman. There is nothing that is even unique about her life. She is not the first woman, and won't be the last, let us hope, who has fallen in love with a man. Not the only woman who has made an ideal out of a quite common-place man, and worships not the real man but her own ideal. That was what happened in Charlotte Bronte's case. Dr. Heger was not the god she thought him. He was quite an ordinary little man with a bad temper, a wife and five children, and considerable ability as a teacher. ' But he was her ideal, and she breathed into it not only the breath of life but the breath of love, and she "preferred him," her ideal, "before all humanity." It is quite certain that her love was not asked, was not wanted ; indeed, it bored the little Belgian professor when she wrote her passionate hungry letters to him. Of the four which we now possess three of them had been torn up, and in the margin of one of them there was a note giving the address of a Brussel's boot-maker — and yet that letter was a bit of Charlotte Bronte's heart ! But, further, even Charlotte's hatred of Madame Heger is not only natural Imt inevitable. There is no mystery about it. Madame Heger seems to have been a good-looking woman — which Charlotte, with her brow protruding full of thought, was not — the mother of five children, against whom justice cannot find one word to say even after the indictment in the " Professor " and " Yillette." Indeed, all recent 152 Mr. J. H. Balfour Browne [June 1, writers have nothing hut praise of the woman. One of them, who was a pupil at the imisionnat some twenty years after Charlotte Bronte's time, and who knew them well, has declared that Charlotte, " so far as these two people (M. and Madame Heger) are concerned, adopted an unjust literary and historic method." But for Char- lotte she was her hero's wife. She stood very properly between Charlotte, whose "heart was breaking," and M. Heger, who was thinking of a new pair of boots. She may even by a little in- tellectual shouldering have been trying to push Charlotte Bronte out of the pensionnat and back to Haworth, both for Charlotte's own sake and for the sake of her school. All this seems to me as very natural, but in the eyes of a passionate woman like Charlotte Bronte it was enough to make her hate her ; and she did ! The portrait of Madame Beck in " Viilette " is painted from her hate, and not from the hfe. But so well did Charlotte Bronte hate as well as love, that she was not content to throw ink at ]\Iadame Heger in the " Professor," and again in " Yillette," we find her even irrelevantly in " Shirley " saying : " I remember seeing a pair of blue eyes that were usually thought sleepy, secretly on the alert, and I knew by their expression — an expression which chilled my blood, it was in that quarter so wonderously unexpected— that for years they had been accustomed to silent soul-reading. The world called the owner of these blue eyes honne petite femme (she was not an English woman). I learned her nature afterwards — got it off by heart, studied it in its furthest and most hidden recesses — she was the finest, deepest, subtlest schemer in Europe." Now this hatred of Madame Heger, which was, as I say, natural enough in this woman, made a poor dictator of many pages in her novels, and these have really led to an unjust view of the character of this woman, that Charlotte not only hated but maligned. Long afterwards she induced even a sane critic like Wemyss Reid to l^elieve her, and to form quite an erroneous opinion of the woman. In a letter he sent me "after the publication of his " Monograph," he said, "Now, do you not see what a painful time that must have l)een at Brussels ? Charlotte, perfectly pure in mind and heart, and yet captive to a clever, shrewd, eccentric man, the Paul Emanuel of the picture ; dogged day and night by a jealous, lying, unscrupulous old Belgian woman, forced to feed upon herself, for she had no confidante until after her return to England (' I cannot write what I want to say,' she cries in one of her letters) ; and debarred from every social pleasure, went through a perfect agony of snffering during these dark years. She returned to Haworth a changed and disillusioned woman." Now, I do not think one of the ei)ithets which he applies to Madame Heger is justified. He has been over-persuaded by Charlotte Bronte, who had })een quite unfair l)oth in her estimate of the woman, and quite unwise in writing her hate in a l)Ook in ,,'arallel columns^ tis it w.ere. to her great unreturned love. Still, I 1917] on The Brontes: A Hundred Years After 153 see nothing at all strange in Charlotte Bronte's distortion of the character of the woman she thought her rival — a rival who had rights to which she had no claim. That she was unjust is quite true, but which one of us is quite judicial in all our estimates of other people, especially when these people stand in our way, with or without a flaming sword, barring our entrance into Eden ? I see no mystery in all this. There is no secret to unfold. There is no one to be scolded or condemned. M. Heger was blind, and Charlotte did not understand his blindness and callousness Avhen she was begging the crumbs of words which might fall from his table. But there is associated with all strong emotions an idea that others are in the same whirlwind as that which is carrying us along. It is a surprise to passion that the outer Avorld seems tranquil, when it is in fierce turmoil. Nothing is a more common delusion in one who loves than that it must be the means of inspiring affec- tion in its object. It was thus with Charlotte Bronte. It was a surprise to her that, while she was in a hot hell of passion, the object of her passion could remain an iceberg. Madame Heger naturally thought more of her school for young girls than of the English governess, and was wise to prevent, if she could, a breath of scandal which would have diumed the brassplate on the door of the pensionnat ; and* Charlotte Bronte is not to be blamed for a forward love — for it is love that is her merit— a deep, passionate love that made her a notable woman, and burned till the heat of her genius lifted the lid of silence and steamed over in those three great books. It is the idea of a prude that love should not be given when it is not asked, and when it is not returned. Love is a free gift, and not a barter. It would be a sorry world if it Avas only to be sold in the market. Some of the very best affections have been pure charities, some of the noblest loves have been unrequited. But these, although unrequited in the world of sense, are never without their reward. And although Charlotte Bronte thought, on leaving Brussels, that her heart would break, although she beat her poor heart against the bars of silence — as we read in those letters now in the British Museum— and suffered for two years the pain of tl;e damned, it was not lor nothing. It was this bitter education which Avas to make, not mar, the woman who was to write " Jane Eyre " and " Yillette.'" It is, of course, the height of folly of a critic who wants readers, or a lecturer who wants a listening audience, to declare that there is no secret to disclose, and that the whole story is quite natural, and could have been understood by anyone Avho took the trouble to listen to Charlotte Bronte herself, not as the writer of an inspired gospel, but as the writer of magnificently prejudiced confessions, which were* just or unjust, true or untrue, as the woman herself. Miss Martineau wrote of her books, " all the female characters in all their thoughts and lives are represented as being full of one thing 154 Mr. J. H. Balfour Browne [June 1, — love," and from her own intellectual point of view, she added there are " substantial heart-felt interests for women of all ages in ordinary circumstances, quite apart from love." That is quite true, but quite irrelevant. It shows only that she did not understand Charlotte Bronte. In answer to it Charlotte wrote : " I know Avhat love is, as I understand it, and if man or woman should be ashamed of feeling such love, then there is nothing right, noble, faithful, truthful, unselfish, in this earth, as I compre- hend rectitude, nobleness, fidelity, truth and disinterestedness." It is this knowing " what love is " that has made her books great, and has left her with an unsullied reputation — notwithstanding her martyrdom for love's sake — for rectitude, nobleness, fidelity, truth and disinterestedness, which has enhanced the w^orld's opinion of womanhood. Now although, as I have said, we ought from her veritable books to have been in no doubt as to the turning-point in Charlotte Bronte's life, there is one mystery to be cleared up, and that is, how a competent critic and careful student like Mr. Clement Shorter^ whose " Bronte" books are as a whole valuable contributions to literary history, should have been betrayed into such a mistake as to Charlotte Bronte's real spiritual relations to M. Heger. In his books he had erroneously, I think, and in the teeth of the evidence and Sir Wemyss Reid's summing up of it, taken up this position — that Charlotte Bronte had admired M. Heger as a master, and respected him as a man of genius, and that such an attitude was quite natural in a woman situated as she was. Even then it struck one that the writer did not know the difference between the passion of love — as Charlotte "knew it"— and the literary toady's lukewarm respect. The temperature of these two is very different when tested even by a not very sensitive thermometer. It was love that was written large over her books, and not book love, but heart love. What must one make of Charlotte's own state- ment that " she returned to Bi'ussels against her conscience, prompted by an irresistible impulse, and so lost peace and happiness for two years " ? Is this the respect one feels for a good teacher, or the sorrow- one suffers from missing his lectures from the estrade ? But again, wdiat was the meaning of her confession in St. Gudule ? AVhat had the poor, spotless governess to confess except her love ? It is of this confession she wrote to Emily as " a real confession." " Better not tell papa," she wrote, " he will not understand it was only a freak, and will, j)erhaps, think I am going to turn Catholic." Not under- stand it ? No one could, unless he had the key to her heart. It was not a freak, it was a "real confession." But not content with the ear of the priest, she has confessed herself with more truth than the sanction of an oath ever gives in "Yillette." "Lucy Snowe w^aited, and hoped and w^aited, but Paul Emanuel never came back." Her father wanted her to make a happy ending to the book, but 1017] on The Brontes: A Hundred Years After 155 how could she, remembering her " loss of peace and happiness for two years " ? Had she altered it, it would have chan«red her veracious work into a trivial lie. One would have thought that these evidences of themselves would have convinced anyone that this was love, and not respect. But then, on the back of all this, came the letters published in 1913, and written during those two years when she had " no peace or happiness." Are these to be explained on this cold hypothesis ? " To wiite to an old pupil cannot be for you an interesting occupation," she wrote to M. Heger, " hut for me it is life:' " Life " — is that the Avay a woman of twenty-eight would address an admired teacher like Huxley or Tyndall ? But again, "xlnd when the sweet and dear consolation of seeing your handwriting, of reading your counsels, fades from me Hke a vision, then fever attacks me, appetite and sleep fail, I feel that life wastes away." Further, " Oh, Monsieur, I know I once wrote you a letter that was not a reasonable one, because my heart Avas clouded with grief, but I will not do it again. I will try not to be selfish, although I cannot but feel your letters are the greatest happiness I know." Again, " How can I endure my life if I am forbidden to make any effort to alleviate my sufferings ? " Is this the dutiful pupil who cannot endure life unless she has her " exercises " corrected by Herr Professor ? "Monsieur, the poor do not need much to keep them alive; they ask only for the crumbs that fall from the rich man's table, but if these crumbs are refused then they die of hunger ! " But the whole four of the letters — which were sent, you remember, surreptitiously by hand, and not by post, for Charlotte still believed in the jealousy of Madame Heger, and naturally did not wish such letters to fall into jealousy's hands — were throbbing with affection, and ought to have convinced anyone that this heart-cry was no mere craving for the notice and companionship of a great man, an exalted literary enthusiasm, but was a woman's wailing affection. That these letters could be written in the course of ordinary acquaintanceship is aljsurd. They are a very sufficient record of lost love, of unrequited affection. But Mr. Clement Shorter, even after reading these indubitable love-letters, continued to regard Charlotte Bronte as nothing more than a faithful pupil — a hero-worshipper of the professor of litera- ture, instead of a passionate disciple of the man ! After reading them, he confided to an interviewer that " they " (the letters) "were actuated only by the immense enthusiasm of a woman desiring comradeship and sympathy with a man of character. There was no sort of great sorrow on her part because Professor Heger was a married man, and it is plain in her letters that she only desired comradeship with a great man." " There is nothing in these letters, published now for the first time, that any enthusiastic woman 156 Mr. J. H. Balfour Browne [June 1, might not write to a man double her age who was a married man with a family, and who had been her teacher." ^Ir. Shorter seems to have a somewhat unusual notion of ordinary correspondence, and I question very much whether it is the ordinary lot of teachers to receive such letters from the enthusiastic admirers of their prelection methods. But Mr. Shorter is wrong in his facts as well as his inferences. Professor Heger was not "double her age," but only eight years older than she was. Charlotte was not w^hat used to be called a " gashing girl," but a woman of twenty-eight. Professor Heger was not a great man, although he was apparently a competent teacher. As for the sorrow that he was a married man, no one has suggested that ; but that a pure, honest unmarried woman may hopelessly love a man who is married does not seem to be beyond the bounds of po.ssibihty. And that a woman would, under such untoward circumstances, suffer " loss of peace and happiness " we can all believe. But it is curious that each of the best-known writers about Charlotte Bronte has made a mistake. Mrs. Gaskell, with a tenderness which is perhaps to her credit, thought that those two years of misery — for which Charlotte herself vouches — were due to the anxiety she felt at the unsteady career and sottish downfall of her brother Bran well, and not to the pure passionate heart-hunger of the woman. This explanation of the gloom of these two bad years was rejected by Sir Wemyss Reid and by more recent writers, and there is next to no evidence in support of Mrs. Gaskell's kind but erroneous view of the cause of these storm-clouds. But Sir Wemyss Reid himself, though he corrected Mrs. Ciaskell, fell into the error, persuaded to it by " Lucy Snowe," that ^ladame Heger was a jealous, spying, cruel woman. This, again, as I have said, and as Mrs. Macdonald shows in her short but adequate book, Avas a mistake ; and it is a mistake which did injustice to the memory of a quite worthy woman. That the author of "Villette" made her as black as a pen could make her was natural enough ; and there was a further excuse for the author — that Madame Heger was under the thin veil of fictional treatment. But the critic had no right to throw more mud at the dead woman. Mr. Clement Shorter, too, in his mistaken admiration for Charlotte Bronte, tries to make her a blue-stocking saint, instead of a real living woman with a heart which has gone out, like Noah's dove, and found no resting-place on the desolate world of waters. How these mistakes were possil)le, in the presence of Charlotte Bronte's own candid and honest confessions in " Villette," and how one of them can l)e persisted in since the publication of the letters of 1844-1S45, which are only, as it Were, a chapter in that novel, it is difficult to conjecture. These are, as I have said, brimful of love. It was love that made the pages of "Villette " so veracious, and make much of it stand out now as if it had been written in letters of lire. It was her love that was precious. That we are loved is a luxury. 1017] on The Brontes: A Hundred Years After 157 That we love is a necessary education, even if, as in her case, it may be associated with a cruel penance. AVe see the result of the great ordeal in her books, whicli, like dropping torches, set other hearts on fire, and can thrill even old hearts which have almost forgotten how to vibrate. It is well to note that it is passion that is the inspiration of the two great books upon which her fame principally rests. Intellectu- ally Charlotte Bronte was narrow. Her sympathies were for the most part the children of habit, and her religion a strait-waistcoat. After her Brussels' experience, however, her heart spoke out. She was no longer narrowed by her early prejudices or iron habits, or confined by the swaddling bands of her religion. She spoke loudly and deeply to other people who have hearts. It was thus, then, that she was great ; it was thus that Harriet Martineau's criticism was as beside the mark as it would be to condemn a rose for having red petals. Here was her great success. A compound of great passion and deep grief, and that in spite of the many minor faults that critics could find with her works. Many of her expressions are hopelessly clumsy. Her real great books were crude in thought, lacking in humour, and had quite a narrow range of sympathy. A great many women writers of fiction have l)een her superiors both in art and in intellect ; but none of their works, which pass us without touch'ng any deep chord, are comparable with these works of hers, which contain the grandeur of one over-mastering emotion. It was this great quality which, when " Jane Eyre " first appeared, caused a good deal of unfavourable criticism from the bloodless prudes and the paltry critics ; but these had to stand aside— the book might not be praised, but it was read. It is this quality which keeps her words alive to-day. A favourite question of the quidnuncs of literature when a writer dies is, " "Will he live ? " It is a question which it is impossible to answer. The answer to it depends not on our estimate of the dead man's or woman's literary merit, but on our knowledge of the tastes and intelligence of the future readers of books. It is difficult to judge even of contemporary merits, or to foretell from one day to another the success or failure of a book or a work of art. Thus,' we know that six publishers at least refused to have anything to do with Charlotte Bronte's " Professor." AVe know that the early venture of the lives of Currer, Ellis, and Acton Bell, the publication of their " Poems," which cost them £50, was a misadventure, for, notwith- standing the great excellence of some of these, only two copies of the book were sold ! We know that Charlotte Bronte's publishers only paid her in the aggregate £1500 for the entire copyright of her three great novels. Are these facts the measure of greatness ? "We know, of course, that the publisher sits in the coach, and the author is between the shafts. But when we remember, that an author for a 158 Mr. J. H. Balfour Browne [June 1, novel trivial in comparison with any of these received £10,000, we must abandon money as a test of merit. How, then, if we cannot tell the tastes of to-day, or the fashions of admiration of our own time, are we to foretell the taste or fashions of our successors, when we are asked of Charlotte and Emily Bronte's works, " AVill they live ? " All I can say is that if these books die, it is not their fault, for they are vital and ought to live ; but it will be your fault, and your children's fault. If they are neglected, it will be because the generations of the future have acquired the taste of a decadent for a literature which is itself in decay. Far less has been said and written about Emily Bronte than about the author of " Jane Eyre." There are many reasons for this harsh neglect. Emily had more aloofness in her than Charlotte. She was of all the oddities at Haworth Parsonage perhaps the oddest. She had, says one accurate critic, " the eyes of a half -tamed creature," but she had also the ways of a half-tamed creature. I have said little of her life because there is so little to say. She, too, was one of the victims of Cowans Bridge School. She, too, became a governess— a poor lot for a woman tamed like Anne, but intolerable for a soaring eaglet like Emily. Charlotte tells us that at the school near Halifax Emily was in " slavery." But think what slavery must be to a woman who could write — Riches I hold in light esteem, And love I laugh to scorn, And lust of fame is but a dream, That vanished with the morn. And if I pray, the only prayer That moves my lips for me, Is " Leave the heart that now I bear, And give me liberty " ! Yes, as my swift days near their goal, 'Tis all that I implore. In life and death a chainiess soul, With courage to endure. She was a pupil, too, at the pens ionjiat at Brussels, and one more ingenious than wise writer has, in the search for origins, suggested that not only was M. Heger the Rochester and Paul Emanuel of Charlotte's books, but that he was also the Heathcliff of that wither- ing literature " Wuthering Heights." AVe have seen that some have told us it was a "great secret" that Charlotte was in love with M. Heger, although she had told us so herself ; but under the dire necessity of accumulating mystery where there is none, each new writer has tried to iiud a new secret with which to whet the blunting curiosity of the public. So we find that ^Irs. Cbadwick, in her book " In the Footsteps of the Brontes," hints that Emily too was in love with the little, black, fiery and kind Professor of the Brussels Athenee, 1*.)17] on The Brontes: A Hundred Years After 159 and tells us that he admired her more than he did Charlotte, on the ground apparently that he said of Emilj, " She ought to have been a man, a great navigator" — evidence of affection which, in my opinion, is about as cogent as the famous "Chops and Tomato Sauce," which was, I believe, admitted as evidence in the leading case of " Bardwell V. Pickwick." All these futile snrmises come from the foolish analysis of books for their sources. The origin of a work of genius like " AVuthering Heights " is not the places and the persons who may have been seen and known by the author, but the inspiration is in the writer. It is not the environment which makes the artist, it is the artist who makes the environment. Charlotte Bronte said of her sister Emily that "she had no model." The haggard players upon her stage are the children of her weird imagination. But here, again, a very competent critic — Sydney Dobel, who described " Wuthering Heights" as "the unformed writing of a giant hand, the large utterance of a baby god " — did make a mistake, and thought that the "giant hand" which wrote both "Jane Eyre" and " AVuthering Heights" was that of Charlotte Bronte. AVe know that was not the fact. It was a stronger hand than that which wrote " Yillette " that wrote that eerie book of passionate tragedy. It was the same hand or " baby god " who wrote " The Old Stoic," "The Last Lines," and "Death!" — a stronger hand even than that which wrote the " Dream of Pilate's Wife." AVe know something of Emily from Charlotte's photographic art, for we find her in the brightest, the healthiest, but the most common- place of her novels, " Shirley." There we have Shirley Keeldar cauterising her own arm when she had been bitten by a dog she believed to be mad. But that is one of the actual facts in Emily Bronte's tragic life. She was a stoic, and bore and suffered the dullness and monotony, which is worse than pain, with a stubborn endurance of a "chainless soul." To the end she endured. She refused to see a doctor, and was just willing to die. She was not the one to flinch when death came to her. AVhen she could scarcely stand she got up out of bed and tried to comb her hair — it was beautiful hair, and Emily had been the beauty of the family — but so weak was she that the comb fell from. her hand into the fire. "See, Martha," she said, "my comb has fallen into the fire and I cannot get it." After that she was so exhausted that she said, " I will see a doctor now." But it was too late to call in a doctor. She leaned on the couch and passed away. She was buried with the others in the Haworth churclj. Her fierce and faithful dog, "Keeper," when they came back from the funeral, " lay down at Emily's door and howled pitifully for many days." The dog had more sense than the British public, which did not know the great loss it had sustained. The writer of "Wutherins: 160 Mr. J. H. Balfour Browne [June 1, Heights," a book -which has some of the force of the plaj-writers of the great age of Greece in its terrible pages — although slowly recog- nized in her greatness, although tardily accepted bj a certain intelligent public — was, in my opinion, a greater genius than her sister, and has made such a deep mark upon the fictional literature of England that it cannot be erased or obliterated. That her intellectual stature was higher, that her genius was greater, can be seen not only when they stand side by side in their novels, but when you compare their poetry. Much that Charlotte wrote was good, but none of it was great. Much that Emily wrote is above praise, and goes straight to our acceptance and belief as the work of the highest genius. Let me, although it is a mistake to patch a lecture with a piece of such supreme merit, for " it taketh away from the garment and the rent is made worse," quote a verse or two : No coward soul is mine, No trembler in the world's storm-troubled sphere. I see Heaven's glories shine, And faith shines equal, arming me from fear. Vain are the thousand creeds That move men's hearts ; unutterably vain. Worthless as withered weeds. Or idlest froth amid the boundless main. With wide-embracing love Thy spirit animates eternal years, Pervades and broods above. Changes, sustains, dissolves, creates and rears. Though earth and man were gone. And suns and universes ceased to be, And Thou wert left alone. Every existence would exist in Thee. These are gems of " purest ray serene," from that cavern of the Haworth parsonage. And these, it may be said, like one swallow, do not make a summer ; but they are certainly the heralds of the coming clement season. A girl who could write Hke this before she was twenty-six years of age, and with only the starved experience of life to her intellectual credit, could have written in time even better ; but what one feels about the crudest of her writings is that they were decisive work, not tentative effort; we feel that, with all their defects, and some of these are glaring enough, there was an obvious strength which did not leave you free to agree or disagree, to acquiesce or withhold your critical assent, but which commandeered your admira- tion and made a slave of your attention. But even her l)est poetry, which does not bulk large, is not so supreme as the rugged prose in which she has spoken of " Heathcliff and Cathy " in the shuddering pages of "AVuthering Heights." Ko weirder work of genius ever came from a woman's pen. 1917] on The Brontes: A Hundred Years After 161 Some foolisli people have called " Wuthering Heights " a dreadful book, aud I have some reason to believe that even now it is not read as it ought to be. Of course, as a story — to say the least of it— it is not prepossessing. In some of its aspects it is almost repulsive. The lurid thunderclouds which bang over the windy moors (that Emily loved) are seldom relieved even by a short lucid interval of sunshine. The hero, Heathcliff, although of course he does not deserve to be called a hero, although human, is possessed of the worst qualities we ascribe to the Devil. But the book blazes with passion — passion sometimes on the verge of insanity. I deny that Emily Bronte had a diseased or a morbid mind, as some have with a near approach to imbecility, asserted. We all have our bad dreams, and this " Wuthering Heights " is one of hers. But it is a dream w^hich does not go when sleep is dissolved in waking, it lives on with us even when day itself dawns to lighten our misery. Remember that the outer world was very liitle to Emily Bronte. She held it at arm's length. She banished it. Liberty — the liberty of aloofness, of a recluse — was, as Charlotte said, " the breath of her nostrils." So far as she knew the world, and her experiences were scarcely a handful, she had not found it a companionable place. It was not a bland world. It had scowled at her like an enemy. Even Brussels, which had made a lasting and harrowing impression on Charlotte, seems to have failed to influence Emily in any way whatever. It was the moors and the rough gnarled folk, which, like the stunted prickly thorns, inhabit the hollows in them, that were her most intimate experiences. Mrs. Dean and Joseph the Calvinist, they are truer to life than any affidavit is to the fact. Joseph, " the wearisomest self-righteous Pharisee that ever ransacked the Bible to rake all the promises to himself and fling the curses to his neighbours," you might And in or near Haworth to-day. But Heathcliff, the two Catherines, and Hareton Earnshaw, although as real, are not folk that have ever been born, but they are people who will never die. In these respects " Wuthering Heights " is one of the most unique books that has been given to the world — and given by an ignorant, nervous, untrained, untamed girl, who was educated only by Divine inspiration. It is easy to depict wooden saints. Much even of good literature is full of these in its niches ; but to paint a flesh-and-ldood man, whose training has stunted any good that was in him, and whose passion has developed into a mania, that is the work of a genius, and it has been accomplished with the ease of strength by Emily Bronte, and by none other. There is no haunted man in all our books so real as Heathcliffe. Of course, " AVuthering Heights " is in prose, rugged prose, but in the result it is a great tragic poem from beginning to end. These great works of Emily are a cry from a deep passionate heart, but it passes the lips as melancholy music. Vol. XXII. (No. Ill) m 162 The Brontes: A Hundred Years After [June 1, There is reason why we Membei's of the Royal Institution should consider the works of these remarkable women. Sir- Humphrey Davy, lecturing" here in 1810, after speaking of the absolute necessity of the strenuous cultivation of experimental philosophy in the National Interest, concluded his lecture with a remarkable appeal for the help that women could give to the movement : " Our doors are open to all who wish to profit by knowledge, and I may venture to hope, that even the female parts of our audiences will not diminish, and that they will honour the place with an attention which is independent of fashion, or the taste of the moment, and connected with the use, the permanence and the pleasure of in- tellectual acquisition." Here, as we know, women are exactly on the same level as men, and have had our suffrage all these years. Speaking of women, he said : " Let them make it disgraceful for men to be ignorant, and ignorance will vanish, and that part of their empire founded upon mental improvement will be strengthened and exalted by time, will be untouched by age, and will be immortal in its youth." He added : " The maxim of improvers is — promote whatever can tend to assist the progress of the human mind, and Letters ivill always he the most powerful engine to this effect. That which is beautiful, that which is pathetic, that which is sublime, can never lose its effect." It is, encouraged by his eloquent words uttered here more than a hundred years ago, that I have ventured to recall these great, almost the greatest, of women writers to your attention. [J. H. B. B.] GENERAL MONTHLY MEETING, Monday, June 4, 11)17. His Grace the Duke of Northumberland, K.G., President, in the Chair. Mrs. E. Harriman Dickinson, Alfred Dobree, Mrs. Florence Stacpoole, were elected Members. The Presents received since the last Meeting were laid on the table, and the thanks of the Members returned for the same, viz. : — 1917] General Monthly Meeting 163 The Secretary of State for India — Report of Board of Scientific Advice for India, 1915-16. 8vo. 1917. Madras: S. Indian Images of Gods and Godesses. By H. K. Gastri. 8vo. 1916. Agricultural Journal, Vol. XII. Part 2. 8vo. 1917. Agricultural Research Institute, Pusa : Bulletin, No. 68. 8vo. 19 17. Astronomer Royal — Report to the Board of Visitors of the Royal Observatory. 8vo. 1916. Accadeniia dei Lincei, Boma — Atti, Serie Quinta, Rendiconti : Classe de Scienze Fisiche, Mathematiche e Naturali, Vol. XXVI. 1" Semestre, Fasc. 9-10. 8vo. 1917. Accountants, Association of — Journal for April 1917. 8vo. Advisory Council, Department of Scientific and huhistrial Research — Report on the Resources of Iron Ores, etc. 8vo. 1917, American Chemical Society — Journal for June 1917. 8vo. Journal of Industrial and Engineering Chemistry for June 1917. 8vo. American Geographical Society— Geographical Review for June 1917. 8vo. American Journal of Physiology — Vol. XLIII. No. 3. 8vo. 1917. Bankers, Institute o/— Journal, Vol. XXXVIII. Part 6. 8vo. 1917. British Architects, Royal Institute o/— Journal, Third Series, Vol. XXIV. No. 10. 4to. 1917. British Astronomical Association — Journal, Vol. XXVII. No. 7. 8vo. 1917. Canada, Royal Society of — Transactions, Third Series, Vol. X. March 1917. 8vo. Chemical Industry, Society o/— Journal, Vol. XXXVI. No. 10. Svo. 1917. Chemical Society — Journal for June 1917. Editors — Athenaeum for June 1917. 4to. Author for June 1917. Svo. Chemical News for June 1917. 4to. Chemist and Druggist for June 1917. 8vo. Church Gazette for June 1917. Svo. Concrete for June 1917. Svo. Dyer and Calico Printer for June 1917. 4to. Electrical Engineering for June 1917. 4to. Electrical Industries for June 1917. 4to. Electrical Times for June 1917. 4to. Electricity for June 1917. Svo. Engineer for June 1917. fol. Engineering for June 1917. fol. General Electric Review for June 1917. Svo. Horological Journal for June 1917. Svo. II Nuovo Cimento for Oct. -Nov. 1916. Svo. Illuminating Engineer for April 1917. Svo. Journal of Physical Chemistry for May 1917. Svo. Joui-nal of the" British Dental Association for June 1917. Svo. Junior Mechanics for June 1917. Svo. Law Journal for June 1917. Svo. Model Engineer for June 1917. Svo. Musical Times for June 1917. Svo. Nature for June 1917. 4to. New Church Magazine for June 1917. Svo. Page's Weekly for June 1917. Svo. Physical Review for May 1917. Svo. Power for June 1917. Svo. Power User for June 1917. Svo. Science Abstracts for May 1917. Svo. Tcheque, La Nation, for May 1917. Svo. M 2 164 ' General Monthly Meeting [June 4, Editors— continued War and Peace for June 1917. 8vo. Wireless World for June 1917. 8vo. Zoophilist for June 1917. 8vo. Florence Biblioteca Nazio^iale Centrale — Bollettino for June 1917. Svo. Florence, Beale Accademia dei Georgofili — Atti, Quinta Serie, Vol. XIV. Disp. 2. Svo. 1917. Franklin Institute— J ovLvna.!, Vol. CLXXXIII. No. 6. Svo, 1917. Glasgow, Royal Philosophical Society — Proceedings, Vol. XL VII. 1915-16. Svo, Geographical Society, Boyal — Journal, Vol. XLIX. No. 6. Svo. 1917. Geological Society of /jowdon— Abstracts of Proceedings, No. 1009. Svo. 1917. Hipkins, Miss Edith — Collection of Books and Pamphlets on "Musical Pitch," etc. Kinnear, Miss M. — Lessons on Chemistry. Balmain. Svo. 1S44. L'Aluminium et les Mdtaux Alcalins. Tissier. Svo. 1858. Introduction a I'Etude de la Chimie. Svo. 1848. Lemons de Chimie. Malaguti. 2 vols. Svo. 1853. Linnean Society— Journal, Vol. XLIII. No. 294, Botany. Svo, 1917. London County Council — Gazette for June 1917. 4to. Meteorological Office — Monthly Weather Reports for May 1917. 4to. Weel ly Weather Reports for June 1917. 4to, Daily Readings for April 1917. 4to. Geophysical Journal for August 1916. 4to. New Zealand, High Commissioner for — Patent Officp Journal, June 1917. Svo. Numismatic Chronicle and Journal, 1916 — Part 4. Svo. 1916. Pharmaceutical Society of Great Britain—J onrnal for June 1917. Svo. Quekett Microscopical'^Club Journal— Sevies 2, Vol. XIII. No. 80, 1917. Svo. Rome, Ministry of Public TForfcs— Giornale del Genio Civile for Feb.-March 1917. Svo. Boyal Colonial Institute— Vnited Empire, Vol. VIII. No. 6. Svo. 1917. Boyal Society of Ai-ts — Journal for June 1917. Svo. Boyal Society of Edinburqh—Froceedings, Vol. XXXVII. Part 2. Svo. 1917. Transactions, Vol. LI. Parts 2-3. 4to. 1915-17. Boyal Society of London — Philosophical Transactions, Series B, Vol. CCVIII. No. 353 ; Series A, Vol. CCXVII. No. 552. Sanitary Institute, i?o?/aZ- Journal, Vol. XXXVIII. No. 2. Svo. 1917. Scottish Geographical Society, Boyal — Scottish Geographical Magazine, Vol. XXXIII. No. 6. Svo. 1917. Selbornc Society — Selborne Magazine for June 1917. Svo. Tdhoku Mathematical Journal — Vol. XL No. 3. 1917. Svo. United States Department of Agriculture — Journal of Agricultural Research, Vol. IX. Nos. 8-10. 1917. Svo. Experiment Station Record, Vol. XXXVI. Nos. 6-7. Svo. 1917. Vnited States Patent Oj^/^cc— Official Gazette, May 1917. Svo. . Washington, National Academy of Sciences— Proceedings, Vol. III. No. 5. Svo. 1917. 1917] General Monthly Meeting 165 GENERAL MONTHLY MEETING, Monday, July 2, 1917. His Grace the Duke of Northumberland, K.G., President, in the Chair. R. D. Pullar, F. E. Robotham, were elected Members. The Presents received since the last Meeting were laid on the table, and the thanks of the Members returned for the same, viz. : — Accademia dei Lincei, Reale, Boma — Rendiconti, Classe di Scienze Fisiche, Mathematiche e iSTaturali. Serie Quinta, Vol. XXVI. 1° Semestre, Fasc. 11-12 ; Classe di Scienze Morali. Serie Quinta, Vol. XXV. Fasc. 7-10. 8vo. 1917. Accountants, Association o/^Journal for July 1917. 8vo. Agricultural Society, Royal — Journal, Vol. LXXVII. 8vo. 1916. Atnerican Chemical Society — Journal for July 1917. Svo. Journal of Industrial and Engineering Chemistry for July 1917. Svo. American Journal of Philology— Yol. XXXVIII. No. 2. Svo. 1917. American Journal of Physiology — Vol. XLIII. No. 4. Svo. 1917. American Museum of Natural History — Bibliography of Published Writings of Henry Fairfield Osborn for the Years 1877-1915. Svo. 1916. American Philosophical Society — Proceedings, Vol. LV. No. S. Svo. 1916. Astronomical Society, Royal — Monthly Notices, Vol. LXXVII. No. 7. 1917 Svo. Memoirs, Vol. LXII. Part 1. 4to. 1917. Boston Public Library— Bnlletin, Third Series, Vol. X. No. 11. Svo. 1917, Cambridge Philosophical Society — Transactions, Vol. XXII. Nos. 10-11. 4to. 1917. Canada, Department of Mines — Museum Bulletin, No. 25. Svo. 1917. Geological Survey Memoirs, Nos. 93, 97. Svo. 1917. Mines Branch, Bulletin, Nos. 14, 17. Svo. 1917. Report on the Building and Ornamental Stones of Canada, Vol. IV. Svo. 1916. Annual Report on Mineral Production of Canada for the Year 1915. Svo. 1917. Congress, Library of. Report. 1916. Svo. Chemical Industry, Society o/— Journal, Vol. XXXVI. No. 12. Svo. 1917. Chemical Society — Journal for July 1917. Svo. Civil Engineers, Institution of — List of Members, 1917. Svo. East India Association — Journal, New Series, Vol. VIII. No. 3. Svo. 1917 . Editors — Athenaeum for July 1917. 4to. Author for July 1917. Svo. Chemical News fo;: July 1917. 4to. Chemist and Druggist for July 1917. Svo. 166 General Monthly Meeting [July 2, Editors — continued Church Gazette for July 1917. 8vo. Concrete for July 1917. 8vo. Dyer and Calico Printer for July 1917. 4to. Electrical Engineering for July 1917. 4to. Electrical Industries for July 1917. 4to. Electrical Times for July 1917. 4to. Electricity for July 1917. 8vo. Engineer "^f or July 1917. fol. Engineering for July 1917. fol. General Electric Review for July 1917. Svo. Horological Journal for July 1917. Svo. Illuminating Engineer for July 1917. Svo, Journal of the British Dental Association for July 1917. Svo. Junior Mechanics for July 1917. Svo. Law Journal for July 1917. Svo. Model Engineer for July 1917. Svo. Musical Times for July 1917. Svo. Nature for July 1917. 4to. New Church Magazine for July 1917. Svo. Nuovo Cimento for Dec. 1916-Jan. 1917. Svo. Page's Weekly for July 1917. Svo. Power for July 1917. Svo. Power-User for July 1917. Svo. Science Abstracts for June 1917. Svo. Tcheque, La Nation, for June-July 1917. Svo. Terrestrial Magnetism for June 1917. Svo. War and Peace for July 1917. Svo. Wireless World for Julv 1917. Svo. Zoophilist for July 1917. Svo. Electrical Engineers, Institution of — Journal, Vol. LV. No. 267. Svc. 1917. Faraday «S'ocie^?/— Transactions. Vol. XII. Parts 1-3. Svo. 1917. Florence, Biblioteca Nazionale C entr ale— Bollett'mo for July 1917. Svc. Geographical Society, Royal—Jouvnal, Vol. L. No. 1. Svo. 1917. Geological Society of London — Abstracts of Proceedings, No. 1010. Svo. 1917. Jugoslav Cowmi^^ee— Southern Slav Library VI. 1916. 12mo. Kyoto Imperial University — Memoirs : College of Engineering, Vol. I. Nos. S-10. Svo. 1917. College of Science, Vol. II. Nos. 1-2. Svo. 1917. London County Council — Gazette for July 1917. 4to. Meteorological Office — Weekly Weather Reports for July 1917. 4to. Daily Readings for May J 917. 4to. Monthly Weather Reports for June 1917. 4to. Geophysical Journal for Oct. 1915. Microscopical Society, Royal — Journal for June 1917. Svo, Milan, li. Scuola Sux)eriore Agricoltura — Annuario, Vol. XIII. Svo. 1917. National Academy of Sciences, Washington — Proceedings, Vol. III. No. 6. Svo. 1917. New York, Society for Experimental Biology — Proceedings, Vol. XIV. No. 7. Svo. 1917. New Zealand Government — Official Year-Book. Svo. 1916. New Zeala7id, High Commissioner for — Patent Office Journal, June 1917. Svo. Statistics, 1915, Vol. IIL 4to. Paris, Academic des Sciences — Comptes Rendus, Tome CLXV, 4to. 1917. Paris, Society d' Encouragement pour V Industrie Nationale — Bulletin for May- June. 1917. 4to. 1917. Paris, Sociite Frant;aise de Physique — Proces-Verbaux, '1914-1915. Svo. 1915-1916. 1917] General Monthly Meeting 167 Pharmaceutical Society of Great Britain — Journal for July 1917. 8vo. Philadelphia — Proceediugs, Academy of Natural Sciences, Vol. LXVIII. Part 3. 8vo. 1917. Photographic Society, Royal — Journal, Vol. LVII. No. 6, 8vo. 1917. Post Office Electrical Engineers, Institution of — Journal, Vol. X. Part 2. Svo. 1917. Royal Asiatic Society — Journal, July 1917. Svo. Royal Society of Arts — Journal for July 1917. Svo. Royal Society of Edijiburgh—Fioceediugs, Vol. XXXVII. Part 3. Svo. 1917. Transactions, Series A, Vol. CCXVII. Nos. 553-554. 4to. 1917. Roijal Society of LonrZon— Proceedings, A, Vol. XCIII. Nos. 651-652 ; XCIV. No. 1 ; B, Vol. LXXXIX. No. 621 ; C, Vol. XXXIV. Nos. 1-2. Svo. 1917. Scottish Geographical Society, Royal — Scottish Geographical Magazine, Vol. XXXIII. No. 7. Svo. 1917. Selborne Society— Selhoine Magazine for July 1917. Svo. Smithsonian histituticm — Miscellaneous Collections, Vol. LXVI. Nos. 14, 16-18 ; Vol. LXVIII. No. 4. Svo. 1917. Contributions to Knowledge, Vol. XXXV. No. 3. 4to. 1916. South African Association for Advanceynent of Science — Report, 1915. Svo. 1916. Statistical Society, EopZ— Journal, Vol. LXXX. Part 3, May 1917. Svo. ToJwku Imperial University, Sendai, Japan — Science Keports, Ist Series, Vol. VI. No. 1. Svo. 1917. United States Department of Agriculture — Journal of Agricultural Research, Vol. IX. Nos. 11-12, 1917. Svo. Experiment Station Record, Vol. XXXVI. No. 8. Svo. 1917. United States, Naval Observatory — Supplement to the American Ephemeris, 1918. Svo, 1917. Upsala, Royal Meteorological 06seri;ator?/— Observations Seismographiques. Svo. 1917. Western Australia, Agent-General — Report of the Department of Mines, 1915. 4to. 1917. Western Society of Engineers — Journal, Vol. XXI. Nos. 9-10 ; Vol. XXII. No. 1. Svo. 1916-17. Wisconsin Academy — Transactions, Vol. XVIII. Part 2. Svo. 1916. GENERAL MONTHLY MEETING, Monday, November 5, 1917. Sir James Crichton-Browne, M.D. F.R.S., Treasurer and Vice-President, in the Chair. The Treasurer announced that the Managers had received an Anonymous Gift of £500 from a Lady Member ; and the following Resolution, passed by the Managers at their Meeting held this day, was read and unanimously adopted : — Resolved, That the Managers of the Royal Institution of Great Britain desire to express to the Lady who has anonymously and unconditionally placed at their disposal, for the purposes of the Institution, the sum of £500 , 168 General Monthly Meeting [Xov. 5, their most grateful appreciation of her munificence and discernment. They accept the Gift as a timely and noble recognition of the good public work the Institution has done in the past, and is still doing, in the acquisition and diffusion of Scientific Knowledge, and as an incitement to maintafn and extend its usefulness in the unique position which it has for more than a century occupied. The Special Thanks of the Members were returned to Richard Pearce, Esq., F.G.S., for his Donation of £100 to the Fund for the Promotion of Experimental Research at Low Temperature. The Presents received since the last Meeting were laid on the table, and the thanks of the Members returned for the same, viz. : — The Secretary of State for India — Report of the Indian Association for the Cultivation of Science for the Year 1915. 8vo. 1917. Proceedings of Indian Association for the Cultivation of Science, Vol. III. Part 1. 8vo. 1917. Geological Survey of India: Records, Vol. XLVII. Part 4. 8vo. 1916; Memoirs, Vol. XLV. Part 1. Svo. 1917. Memoirs of the Department of Agriculture : Entomological Series, Vol. V. Nos. 2-3 ; Botanical Series, Vol. IX. No. 3. Svo. 1917. Accademia dei Lincei, Boma — Atti, Serie Quinta : Rendiconti. Classe de Scienze Fisiche, Mathematiche e Naturali, Vol. XXVI 2^ Semestre, Fasc. 1-6; Classe di Scienze Morali, Vol. XXV. Fasc. 11-12; Vol. XXVI. Fasc. 1-2. Svo. 1917. Accountants, Association of — Journal for Aug.-Sept. 1917. Svo. American Chemical Society— Journal for July-Oct. 1917. Svo. Journal of Industrial and Engineering Chemistry for Aug.-Oct. 1917. Svo. American Geographical Society — Geographical Review for July-Oct. 1917. Svo. American Journal of Philology — Vol. XXXVIII. No. 3. Svo. 1917. American Journal of Physiology — Vol. XLIII No. 4 ; Vol. XLIV. Nos. 1-3. Svo. 1917. American Philosophical Society — ^Proceedings, Vol. LVI. Nos. 1-2. Svo. 1917. Asiatic Society, Royal — Journal for Oct. 1917. Svo. . Bombay Branch Journal, Vol. XXIV, No. 3. Svo. 1917. Astronomical Society, Royal — Monthly Notices, Vol. LXXVII. Nos. 8-9. Svo. 1917. Australia, Census of the Commonwealth of — Vol. I. Appendix A. 4to. 1917. Bankers, Institute o/— Journal, Vol. XXXVIII. Part 7. Svo. 1917. Beck, James M., LL.D. — The War and Humanity. Svo. 1917. Boston, Society of Natural History — Occasional Papers, No. 13. Svo. 1915. Memoirs, Vol. VIII. No. 2. 4to. 1916. Proceedings, Vol. XXXV. Nos. 2-3. Svo. 1915. British Architects, Royal Institute of — Journal, Third Series, Vol. XXIV. Nos. 12-14. 4to. 1917. British Association for the Advancement of Scietice — Report of the Eighty- sixth Meeting (Newcastle-on-Tyne, 1916). Svo. 1917. British Astronomical Association — Journal, Vol. XXVII. Nos. S-9. Svo. 1917. Memoirs, Vol. XXI. Part 1. Svo. 1917. List of Members, 1917. Svo. Buenos Ayres — Bulletin of ]Municipal Statistics for Jan. -June 1917. 4to. Cambridge Observatory — Report of the Observatory Syndicate, 1915-16. 4to. 1917. Cambridge Philosophical Society — Proceedings, Vol. XIX. Parts 2-3. Svo 1917. 1917] - General Monthly Meeting 169 Canada, Department of Mines — Preliminary Report of the Mineral Production of Canada during the Calendar Year 1916. 8vo. 1917. Summary Report of Geological Survey for the Year 1916. 8vo. 1917. Geological Survey : Memoirs, Nos. 84, 87, 98. 8vo. 1916-17. Mines Branch : Bulletin, No. 15. 8vo. 1917. Carnegie Endowment for International Peace — Year-Book for 1917. 8vo. Chemical Industry, Society o/— Journal, Vol. XXXVI. Nos. 14-19. 8vo. 1917. Chemical Society — Journal for Aug.-Oct. 1917. Chemistry, Institute o/— Proceedings, Part 3, 1917, 8vo. Chicago, Field Museum of Natural History — Publications : Zoological Series, Vol. X. No. 15, Vol. XII. No. 1 ; Report Series, Vol. V. No. 2 ; Anthro- pological Series, Vol. VI. No. 4. 8vo. 1917. Chicago, John Crerar Library — Twenty-second Annual Report, 1916. Svo. 1917. Consolo, En) ico— The War in Italy, Vols. VII.-IX. 4to. 1917. Dax, Sociite de Sor^a— Bulletin, 1916, Nos. 3-4. 8vo. Donald, James — New Testament Christianity. By Lancelot Oliver. 8vo. 1911. Editors — Aeronautical Journal for April-Sept. 1917. 8vo. Athenaeum for Aug.-Oct. 1917. 4to. Author for Oct. 1917. 8vo. Chemical News for Aug.-Oct. 1917. 4to. Chemist and Druggist for Aug.-Oct. 1917. 8vo. Church Gazette for Avig.-Oct. 1917. Svo. Concrete for Aug -Oct. 1917. Svo. Dyer and Calico Printer for Aug.-Oct. 1917. 4to. Electric Vehicle for Sept. 1917. Svo. Electrical Engineering for Aug.-Oct. 1917. 4to. Electrical Industries for Aug.-Oct. 1917. 4to. Electrical Times for Aug.-Oct. 1917. 4to. Electricity for Aug.-Oct. 1917. Svo. Engineer for Aug.-Oct. 1917. fol. Engineering for Aug.-Oct. 1917. fol. General Electric Review for Aug. 1917. Svo. Horological Journal for Aug. -Sept. 1917. Svo. II Nuovo Cimento for Feb. -June 1917. Svo. Illuminating Engineer for June-Aug. 1917. Svo. Journal of Physical Chemistry for June-Oct. 1917. Svo. Journal of the British Dental Association for Aug.-Oct. 1917. Svo. Junior Mechanics for Aug.-Oct. 1917. Svo. Law Journal for Aug.-Oct. 1917. Svo. Model Engineer for Aug.-Oct. 1917. Svo. Musical Times for Aug.-Oct. 1917. Svo. Nature for Aug.-Oct. 1917. 4to. New Church Magazine for Aug.-Oct. 1917. Svo. Page's Weekly for Aug.-Oct. 1917. Svo. Physical Review for Julv-Sept. 1917. Svo. Post Office Electrical Engineers' Journal, Vol. X. Part 3. Svo. 1917. Power, for Aug.-Oct. 1917. Svo. Power User for Aug.-Oct. 1917. Svo. Science Abstracts for Aug.-Oct, 1917. Svo. Tcheque, La Nation, for July-Sept. 1917. Svo. Terrestrial Magnetism for Sept. 1917. Svo. War and Peace for Aug.-Oct. 1917. Svo, Wireless World for Aug.-Oct. 1917. Svo. Zoophilist for Aug.-Oct. 1917. Svo. Electrical Engineers, Institutioyi o/^Journal, Vol. LV. No. 268. 4to. 1917. Faraday ifow.se— Journal, Vol. VII. No. 4. Svo. 1917. Floi-ence Bihlioteca Nazionale Centrale — Bollettino for Aug.-Sept. 1917. Svo. 170 General Monthly Meeting [Nov. 5, Formosa, Government of — Icones Plantarum Forniosanarum, Vol. VI. 8vo. 1916. Franklin Institute- Journal, Vol. CLXXXIV. Nos. 1-4. 8vo. 1917. Geneva, Society de Physique — Comptes Rendus, No. 33, 1916. 8vo 1917. M^moires, Vol. XXXVIII. Fasc. 6. 4to. 1917. Geographical Society; Royal — Journal, Vol. L. Nos. 2-5. Svo. 1917. Geological Society of London — Quarterly Journal, Vol. LXXII. Part 2. Svo. 1917. List of Members, 1917. Geological Survey of Great Britain — Summary of Progress, 1916. Svo. 1917. Harvard College Observatory — Seventy-first Annual Report of the Director, 1916. Svo. 1917. Horticultural Society, Royal — Journal, Vol. XLII. Parts 2-3. Svo. 1917. Humanitarian League, The — The Flogging Craze. By Henry S. Salt. Svo. 1916. hnperial College of Science — Calendar, 1917-lS. Svo. Imperial Institute — Bulletin, Jan.-Mar. 1917. Svo. Iron and Steel Institute— J ouvnsil, Vol. XCV. Svo. 1917. Life-Boat Institution, Royal National — Journal for Aug. 1917. Svo. Linnean Society — Transactions : Botany, Vol. IX. Part 1 ; Zoology, Vol. XVII. Part 3. 4to. 1916-17. Literature, Royal Society of — Transactions, Vol. XXXV. Svo. 1917. Londofi County Council — Gazette for Aug.-Oct. 1917. 4to. London Society — Journal, No. 14. Svo. 1917. Manchester Literary and Philosophical Society — Memoirs and Proceedings, Vol. LXI. Part 1. Svo. 1917. Mechanical Engineers, Institution o/— Proceedings, 1917, Jan. -May. Svo. 1917. Meteorological Office — Monthly Weather Reports for July-Sept. 1917. 4to. Weekly Weather Reports for Aug.-Oct. 1917. 4to. Daily Readings for June-Aug. 1917. 4to. Geophysical Journal for Dec. 1915 ; Jan.-March, 1916. 4to. Meteorological Society, Royal — Journal, Vol. XLIII. No. 1S3, July. Svo, 1917. Metropolitan Asylums Board — Annual Report, 1916. Svo. 1917. Microscopical Society, Royal — Journal, 1917, Parts 4-5. Svo. Monaco, Musee Ocdanographique — Bulletin, Nos. 326-32S. Svo. 1917. Montpellier, Academic des Sciences— Bulletin, Nos. 5-7. 1917. Svo. National Physical Laboratory — Collected Research, V^ol. XIII. 1916. 4to. Report for year 1916-17. 4to. 1917. New South Wales, Royal Society of — Journal and Proceedings, Vol. L. Parts 2-3. Svo. 1916. New York Academy of Sciences —Annals, Vol. XXV. pp. 1-30S. Svo. 1916; Vol. XXVII. pp. 193-203, 205-214. Svo. 1917. New York, Society for Experimental Biology and Medicine — Proceedings, Vol. XIV. No. S. Svo. 1917. New Zealand, High Commissioner for — Patent Office Journal, July 1917. Svo. Statistics, 1915. Vol. IV. 4to. 1916. Numismatic Chronicle and Journal, 1917, Parts 1-2. 1917. Svo. Paris, Academic des Sciences — Tomes 160-162, 4to. 1915-16. Paris, Soci4t 3rd, 3 days 4th bubble (water in vessel) 24 ,, 4th, 18 days 5th bubble (water in vessel, vibration) 6th bubble (water in vessel) 19 55 " 5th, 6th, 11 days (hot weather, &c,) 63 days (hanging on 4 cm. sup- port) 7th bubble (water in vessel, out in yard, frosty at end) 31 " 7th, 42 days (globe became con- taminated) * A hanging bubble kept in air saturated with water vapour, of an initial capacity of 4 • 5 litres, took 322 days to completely collapse from air transfusion. 1917] on Soap Bubbles of Long Duration 187 The first item of Table 1 includes tlie first bubble (50 per cent, glycerine, 5 per cent, ammonium oleate), which kept its colour instead of developing- to blackness. This was caused by moisture left after cleaning the 5-litre bottle in which it was blown ; no more moisture than enough to give a bedewed appearance was left, bat this distilled to different parts of the vessel, as the local temperature altered, and resulted in a movement of water vapour sufficient to keep the absorbent bubble thick enough to show colours. Sharply marked zones of different colours are a feature of such bubbles. For this an undisturbed atmosphere is necessary ; other- wise convection currents in the bubble will, by continual mixing, prevent the quiet development of separate colour zones. The tem- perature alterations must, therefore, be small. From the records of one bubble the following appearances were noted : — On the 15th day. 20 cm. in diameter : sharp boundary line at " 60° N. Lat." between steel-blue above and greenish-yellow below : similar boundary between blue-green and blue-purple at " 50° S. Lat." Large drop on bubble. On the 18th day. Diameter, 19*4 cm.: three sharp Une boundaries : green to purple at " 30' X." : dark green to light green at ^' 70"" S." : light green to thin magenta at " 80° S." : intense green disc at lowest part. Drop fallen off. On the 2-l:th day. Main area of bubble fairly uniform red- purple : boundary at " 75° N." to pale green above, and to deep green below at ' 60° S." Graded Newton's rings of mauve and green below this. The life of the bubble shown in the second item of Table 1 was double that of those in the first item, namely, 98 days instead of about 40 days. The solution used had 10 per cent, of ammonium oleate instead of 5 per cent, as before. This factor, however, had less influence than the generally lower temperature of under 11° C. instead of up to 20° C. as before. Between the 75th and 95th days there was a contraction from 11*4 cm. diameter to 10*4 cm., while still remaining coloured. By the 95th day the bubble had become too dilute to maintain any colour, and accordingly developed to the thinnest or '• black " stage in the upper half. On the night of the 98th day the temperature of the Laboratory fell to near freezing point, and the bubble did not survive this change. The next item refers to a bubble of 5 per cent, potassium oleate in 50 per cent, glycerine. The 12-litre aspirator in which it was blown was well dried, and, further, was placed in a vault where only slow and small temperature variation occurs. In three months the variation was from 9^ C. to 11° C. This solution was chosen because of its property of giving extremely slow development to the " black " stage. The result was that in 95 days the zone of black had only extended down to " 25° S. Lat.," the remainder being so thick as only to be feebly coloured with faint pink-and-green rings, probably 188 Professor Sir James Dewar [Jan. 19, "up to a liiindred times the thickness of the black supporting zone above. The final collapse may have been associated with this con- dition ; moreover, the potash soap is very sensitive to slight alkalinity of the glass, — no other distnrbing canse was observed. Table 2 shows the lives of two sets of large bubbles under similar conditions, in two vessels of 200-litre capacity ( Fig. 4). These vessels were cylindrical glass globes, used in tlie Laboratory twenty-five years ago in the production of liquid ethylene. They had short necks, Fig. 4. 14 cm. diameter, which were fitted with good, cleansed india-rubber corks to carry the blowing tubes, vetit tubes, etc. An oxidised steel wire ring was used to support the majority of the bubbles. These rings were about 12 cm. diameter, and were raised, by three supports of the same oxidised wire, to about 25 cm. above the bottom of the globe. For bubbles so supported the blowing tube was less than 1 cm. diameter ; it had a constriction of about 1 mm. bore, a few centimetres above the lower end. A few drops of li(]uid from the reservoir above were decanted down to fill the constriction for the 1917] on Soap Bubbles of Long Duration 189 purpose of starting the bubble. The reservoir is shut off bv a stop- cock from the blowiuii' tul)e, as it is not advantageous for the soap sokition to be exposed to the current of air used in expanding the bubble : a side tube is sealed in for the air inlet. The blowing tube is mounted, so that it can slide up and down while remaining air- tight. A few small bubbles are first blown and run round the supporting ring to wet it. A bubble is then blown to about 4 cm. greater diameter than the ring, while resting on one side of it. This is done bv holding the end of the blowing tube sufficiently out of the centre, and steadily raising it until the bubble is about 15 cm. diameter, when it is allowed to come into full contact with the whole ring, and the expansion is continued until the requisite diameter of about 40 cm. is reached. Meanwhile, the blowing tube is continually raised through its sliding support tube in the india-rubber cork, and finally Avithdrawn by a to-aiid-fro spiral movement upwards. In one case when the bubble became free from the tube, a complex up-and- down oscillation took place in a period of about two seconds, and with an initial amplitude approaching 3 cm. at the upper periphery. By leaving the blowing tube in the bubble the advantage of an added steady support is secured ; this is unsatisfactory when measures of contraction are being made, but it certainly helps to prevent undue disturbance, especially in the early stages, when the bubble is liable to be thick and somewhat top-heavy on the 10 cm. ring. It can be seen from Table 2 that there is a general increase in length of life of the successive bubbles in both the first and second vessels. The last items, in both cases, snow a shorter life ; this, however, was due in one case to the vessel being in the open air in winter, whereby its temperature at the end went below freezing point : and in the second case, to the globe becoming contaminated, from the displacement of a badly-fitting tube. The irregularity between the fourth and fifth items was explained by the hot weather (temperature over 20° C). The maintenance of colour in such large bubbles was not easy. For this purpose a good circulation of water vapour in the vessel seems desirable, as the mere presence of a litre or two of water in it was not entirely effective. A wet cloth placed on the upper part of the vessel (seen in Fig. 4) by its own evaporation maintained a slightly cooler area, thus promoting the condensation there of drops of water. A flow of water vapour up through the vessel was thus obtained, which being partly absorbed by the glycerine in the bubble did for a time maintain, and even increase, its thickness and colour. In the later stages also, when the bubble material has thus become altered in the relative proportions of its constituents, vaporisation from the bubble may take place, and then the opposite effect is observed ; distillation causing the thickness to deciea-e, so that two or three colours are passed through in as many hours. A few degrees rise of room temperature causes the same change, especially in diluted 190 Professor Sir James Dewar [Jan. 19, bubbles. The lowering of the temperature will then reverse the effect and the bubble is seen to thicken. The ordinary variations from night to day are sufficient to cause many such repetitions in the same bubble. Thus, when it was thought to increase the pro- portion of water vapour by warming the water in the vessel, and thereby increasing the thickness by a greater absorption, the rise of temperature counteracted any increased absorption ; and once more the bubble became thinner. The removal of the wet cloth allows the condensed water to distil off more vapour, which is often sufficient to thicken the bubble. This is best seen when a good condensed deposit is accumulated before blowing the bubble, as was done in one case (see fifth bubble, first vessel) by the application of bags of ice. The bubble, which was then blown, remained almost entirely coloured throughout its life. A small zone of black came and went, and the thickness w^as reduced once or twice by a damp cloth. The w^eather was rather warm at first, but became more temperate (the time was August). Finally, the bubble was very much thickened, and prob- ably burst from this cause ; for as the bubble became thick, it overhung the ring unsymmetrically, and most probably became lop- •^ided enough to swing round and touch the vessel. The supporting ring was seen to be slightly out of the horizontal, and in vibration due to the working machinery in the room below. The fourth bubble in the second vessel : during the first week untouched ; maintained green and pink colour ; thick and overhanging the ring ; then frequently treated by damp cloth above, thinned while cloth was on and thickened when cloth was removed ; at third operation, bubble half black : next time, the water below was warmed by the arc lamp beam : result, 85 per cent, black obtained. The fifth bubble in the second vessel lasted eleven days only ; short life in the hot weather ; disturl)ed at the end by dainp cloth, also by vibration ; thinned to silver and black ; first three days thickened rapidly by absorption from the deposit of water ; im- mediately after being blown sagged over ring ; then steadily thinned through several beautiful grades, until on the fifth day at 19^^ C. it was amber and purple, with silver above. Damp cloth then put on ; the silver extended all over, followed by a fairly uniform development of black. Two grades of black were noted— the deepest black being only a zone of a few centimetres at the top. The top of the bubble was approximately 1 cm. higher wdien black than when thick and heavy. The sixth bubble in the first vessel went quickly black in two days (possibly from an unusual excess of ammonia in the soap solution), and remained so until the end of the first week. It then thickened to various colours for four weeks, and once again went quickly black. This condition remained for three weeks, during which time a steady diminution of diameter was measured. The blowing-tube having l)een left attached to the bubble, the contraction had by this time narrowed 1917] on Soap Bubbles of Long Duration 191 down the upper part of the Inibble till it became a neck. When this divided, the disturbance was probably more than the very dilute and very thin film could survive, for the next morning it had gone. The seventh bubble in the second vessel was suspended from a 4-cm. nozzle ; it lasted from 27th October to 9th December. The tempera- ture fell from 15° C. at first to below 10° C. after the first week. The bubble burst after a sudden rise of temperature from 6° to over 9% accompanied by a considerable fluctuating fall in the barometer, when it was found, by the optical test, that the air in the globe had become contaminated. This bubble afforded an opportunity for observing the rate of fall of condensation drops. Excluding the pre- liminary drainage, the results are shown in the annexed diagram (Fig. 5). ^DAtb Fig. 5. — Absorption of Water Vapour by a 40 cm. Bubble. Eate of fall of drops. GrAS Transference Through Bubbles at Atmospheric Pressure. Long-lived bubbles regularly diminish in diameter, and most rapidly when thinned to " black." The contained air or other gas is at a somewhat higher pressure than the atmosphere in which the bubble stands, and therefore tends to pass out ; with the result that there is a continual diminution in size. With black bubbles up to about 15 cm. the change becomes very evident in about a week. Using a cathetometer, the contraction can be observed accurately from day to day. The subjoined diagram (Fig. 6) shows the con- traction, measured every third day, of a black bubble in hydrogen. From an initial diameter of approximately 11 cm., by the twenty- third day it had completely contracted. It will be noticed that the rate of contraction was accelerated as the diameter decreased. The gradational diminution in diameter of black bubbles made from soap solutions of different compositions, and with diameters up to 46 cm., was periodically measured with the cathetometer. The rate of gas transference from within the bubble outwards at any time can be obtained directly from the mean daily reduction in -diameter at that time, and is readily measured by dy/dx, the slope of 192 Professor Sir James Dewar [Jan. 19, the tangent drawn at the desired point of the contraction curve. The amount of the gas transference, in cubic centimetres per day through unit area, is then equal to one half of the daily rate of reduction in diameter, measured in centimetres. This follows directly from the simple properties of a sphere ; for if S and Y be respectively the surface and volume, and 1) the diameter, then S ^ tt D^, and V = - D^, so that d Y 6 D2.^/D = I S.^D, therefore c?V/S, the rate of gas transference per unit surface, = ^.^ D, which is half dy/dx, the daily rate of reduction in diameter shown by the slope of the tangent already referred to. (Oem's 0 3 6 C^ 12 15 18 ^l 2:^^ DAYS Fig. 6.— Black Bubble in Hydrogen. Decrease in size at 3-day intervals. Some of the results obtained are shown in the following Tables 3, 4, 5, and 6, in which are given respectively (1) the diameter of the bubble on which the measures were made ; (2) the corre- sponding internal excess pressure, above the exterior air pr» ssure, given in mm. water ; and (8) the measured value of d'D/2, representing, as shown above, the rate of gas transference in c.c. per day pns^ing out through each square centimetre of the bubble when at the diameter given m line (1). Gas Transference through JUack Air llubhles. Table 3. — 50 per cent, glycerine, 2^ per cent, soap ; hanging on glass tube. Diameter .... Internal pressure (laa transference rate 6 7 8 0-30 0-26 0-23 0-065 0-035 0-030 1917] on Soap Bubbles of Long Duration 1!)3 Table 4. — 25 per cent, glycerine, 4 per cent, alcohol, 5 per cent, soap ; banging on glass tube. j Diameter 10 12 Internal pressure . 0-18 0-15 Rate 0-15 0-11 Table 5. —Two large black bubbles (thinned b} hanging on a glass tube. water condensation) ; <•) (11) Diameter ... 38 38 Internal pressure . 0-057 0 057 Rate ..... 0-023 0-015 The corresponding rates calculated for similar bubbles 10 cm. diameter would be : (I) 0-086 ; (2) 0*58 ; whereas a bubble subject to water condensation, but still retaining some colour, contracted from 11 cm. diameter on its 75th day to 10 cm. diameter on the 95th day, being a diminution of 1 cm. in twenty days, giving an average daily rate of gas transference per unit of surface equal to 0*025 cm., or about one-third the calculated rate for a black bubble of the same diameter. Table 5 may be amplified as follows, to show more completely what is occuriing in bubbles of this size : — Table. 6. — Gas transference through 38 cm. black bubbles in air (dilute glycerine-oleate solution). Kesults Diminution in diameter Diminution in volume Gas transference through each sq. cm (i) 5 weeks l)lack* (ii) 2 weeks black f Daily 0-045 cm. 0-03 cm. Total 1-58 cm. 0-41 cm. Daily 0 • 103 litres 0-067 litres Total 3-60 litres 0-940 litres Daily 0.023 c.c. 0-015 c.c. Total 0-805 c.c. 0-205 c.c. ♦ No. (j) hanging on a glass tube. f Xo. (ii) less diluted than No. (i), and resting on a steel wire ring. Vol. XXII. (No. Ill) o 194 Professor Sir James Dewar [Jan. 19, In the case of a hanging bubble as large as 38 cm., referred to in Table 6, the total reduction in the diameter amounts only to 1'58 cm. in five weeks. The volume of such a bubble is over 30 litres, and the surface has an area of 5,000 square cm., while the total weight is only about half a gram. Being thinned to the " black " stage, it has a maximum thckness of approximately fifteen /x/x's ; that is to say, one and two-third million such fihns if superposed would have a total thickness of one inch. The internal excess pressure is of the order of a twentieth of a millimetre of water, r^tt-s Fig. 7. or about one fifteen-thousandth part of the pressure of the atmosphere. Nevertheless the actual volume of air which passed out of the black bubble in five weeks was 3 * 6 litres, or every minute a layer of air mole- cules some ten to eleven times the thickness of the wall of a black bubble of 38 cm. diameter passed through it. Hence the thickness of the layer of air which at ordinary temperature passes through the film in one second is 10/60ths of the thickness of the film, or 2*5 /x/z's — in other words, a layer of air as thick as the film would take six seconds to pass through it. Again, the mean free path in air is 100 ///i's, which is nearly seven times the thickness of the film, and therefore some forty times the thickness nf the layer of air passing through the film in one second. Theoretically the internal pressure 1917] on Soa.p Bubbles of Long Duration 195 in a black bubble of less than about 1 cm. diameter would be sufficient to cause the transference of a layer of gas of a thickness equal to the length of the mean free path. The rate of transference in bubble ii. is only about three-quarters of that in bubble i. A black spherical air bubble about 42 cm. diameter, supported by a nozzle above and a small fixed horizontal glass ring below : thus keeping its vertical diameter constant, altered to an ovoid shape, 33 cm. horizontal diameter, in 109 days. The lessened internal air pressure caused by the ovoid form reduced the rate of the air trans- ference to about one quarter that in bubble i. (Table 6). Gas Transference through Black Bubbles in Hydrogen. A few hydrogen bubbles blown in hydrogen were also observed. A suitable vessel for these bubbles is shown in Fig. 7. An oxidised iron-wire ring is seen supporting a bubble, not yet completely black, within the flat-bottomed vessel A (about 3 litres capacity). The filling of the vessel A with hydrogen is attended with considerable difficulty, and requires great care in order to obtain " optical emptiness " in the vessel. The nozzle B should be pushed down nearly to the bottom, while the vessel A is being filled with hydrogen by the tube 0 (used later as an outlet when expanding the bubble). No Tyndall cone will be visible if the vessel is properly filled. The bubble is then blown on B in the usual way, and expanded and let down to rest on the wetted ring already prepared for it ; or it may be left suspended from the nozzle. Both inlet and outlet tubes are protected by glycerined cotton-wool filters. The contractions observed in hydrogen bulbs were generally more rapid than those of similar-sized air-bubbles, as shown in Tables 7, 8, 9, where the units are the same as in the last Tables. Table 7. — 50 per cent, glycerine, 5 per cent. soap. Hanging from glass nozzle. Standing on iron-wire ring Diameter 4 6 8 10 6 8 10 Internal pressure . 0-45 0-30 0-23 0-18 0-80 0-23 0-18 Eate of gas transfer- ence .... 0-22 0-14 0-10 0 053 0-253 0-218 0-190 Table 8. — 33 per cent, glycerine, 3 per cent, soap glass nozzles. jing from Diameter .... Internal pressure . Rate of gas transference 4 6 8 10 I . ' 0-45 j 0-30 0-23 | 018 0 31 i 0-25 0-20 I 0-17 2 196 • Professor Sir James Dewar [Jan. 19, Table 9.— Approximately 1 per cent, glycerine-soap ; pale golden colour ; hanging from glass nozzles. Diameter ^ 6 | 8 Internal pressure 0 • 55 0-36 0-28 Rate of gas transference 0-285 0-103 0-050 The internal pressure was not determined for every bubble ; the values given above were deduced from results obtained with typical bubbles connected to an alcohol nearly-horizontal displacement mano- meter. The instrument gave w4th 1 mm. of water pressure a dis- placement of the order of 100 mm. of the alcohol column. A study of these results shows at once that there are obscure factors in some cases, causing notable divergences, even when the conditions are not greatly altered. Other experiments have shown that small differences in "^composition have in many cases a large effect, on the behaviour of these thin films. Table 4 (air bubbles) shows that 4 per cent, of alcohol added to the soap solution increases the rate of gas transference through an air bubble. The constancy in thickness of the " black stage " is undoubtedly subject to variation in different solutions. Johonnott, using a large number of small black films in a Michelson interferometer, found that there were at least two values for the thickness of the black film he measured, and that the additions of either glycerine or potassium nitrate tended to give the thicker of the two.'^ In last year's Discourse a description of five distinct grades of black was given, obtained with soap solution containing over 30 per cent, of glycerine. The film covered a thin glass frame in an exhausted glass vessel. These grades were seen to be unstable, coalescing to the deepest or thinnest black when a portion of soap solution was brought in contact with the lower pai't of the glass frame. It is possible that a few ])er cent, of alcohol, with its low viscosity and surface tension, might result in a still thinner black stage. Gas Transference THROuan Bubbles at Pressures OTHER THAN ATMOSPHERIC. A bubble of about 10 cm. diameter, shown in an exhausted flask (Fig. 2), in which the air pressure had been reduced to the order of a fraction of a mm., was seen to contract visibly from the rapid percolation of the air from within outwards. Under such con- * "Thickness of the Black Spot in Liquid Films." By Edwin S. Johonnott, Jun., llyerston Physical Laboratory, University of Chicago. Phil. iNIag., xlvii., p. 501. 1917] on Soap Bubbles of Long Duration 197 ditions the small internal excess pressure of about 0-2 mm. water, necessary to maintain a 10 cm. bubble, is a very large proportion, say about 10 per cent., of the total air pressure in the flask. There is, therefore, a proportionately small resistance to its percolation through a film sufficiently thin. As the air pressure in the vessel is increased, the time for complete contraction becomes greater, Itecause the internal excess pressure is a relatively smaller proportion of the total opposing pressure ; thus when the containing vessel is at atmospheric pressure, the 10 cm. bubble is distended by only Tf^V^th of this total pressure. There is therefore a proportionately small force urging the contained air to pass out compared with that where the vessel wa^ under a pressure of only a fraction of a mm. The result is naturally that the complete contraction takes weeks instead of minutes. In the same way if a bubble be formed in a strong glass vessel charged to, say, 10 atmospheres, then even after six months, during the major part of the time being black, no sensible diminution in diameter was detected. The measures of contraction at very low pressures were hindered by the difficulty in securing uniformity of thickness in the film. The black bubbles when obtained are extremely fugitive, as they contract so quickly. Then also the ammonium oleate solutions, which are so well adapted for obtaining black bubbles, do not remain of the same composition under low air pressures, due to the removal of the volatile easily-dissociated ammonia. The results of some of the attempts with ammonium oleates are given in Fig. 8, showing the contraction at pressures of 1 mm. and 5 mm. Hg. respectively, with approximately the same bubble thick- ness. The curves in Fig. 9 show the relative rates of contraction with potassium olcMte at three different thicknesses of bubble, all at the same pressure of just over 1 mm. Hg. The first of these two diagrams show's that at less than 1 mm. pressure of air in the vessel, a 14 cm. bubble composed of 3 per cent, ammonium oleate in 30 per cent, glycerine, of intense green colora- tion, contracts completely in about 17 minutes ; whereas if the air pressure be raised to 5 mm., the contraction of a similar bubble has only gone from 14 cm. to 11 J cm. in the same time, and to 10 cm. in 25 minutes. The second diagram shows that a bubble 10 cm. in diameter, composed of 5 per cent, potassium oleate, 50 per cent, glycerine, and almost too thick to show colour, takes 47 hours to contract to 6 cm. ; but when a bubble of similar size and composition is thinned to intense green, the same amount of contraction occurs in 9 hours : when further, the black stage is secured, the time for complete collapse from 3 cm. diameter is only 25 minutes. The green bubble, from its graph, would have taken from 2 to 3 hours for the same contraction. Such preliminary results may serve at least to point the way to a more complete inquiry. Fig. 8. — Bubbles of Ammonium Oleate, 3 per cent, in 30 PER CENT. Glycerine. Thinned to first green. Fig. 9. — Bubbles of Potassium Oleate, 5 per ci-,nt. in 50 PER CP2NT. Glycerine. Air pressure over 1 mm. Hg. 1917] on Soap Bubbles of Long Duration 199 Effect on the Gas Tra^jj^sference Rate of the Composition of the Soap Solution. The internal excess pressure P, in a bubble of constant composi- tion, and therefore of constant surface tension T, enclosed in a vessel sealed off from the atmosphere, varies inversely as the diameter D, according to the law F = 4T/D. Hence if the rate of gas transference varies directly as the internal excess pressure, it will consequently vary inversely as the diameter. Now, in Fig. 6, taking the oriirin^at the point where the bubble vanishes, and measuring x (time) horizontally to the right in days, and y (diameter) vertically downwards in cms, we found tliat the gas - 1 . . d y ^ d y k transrerence was measured at any time x m - ^ \ hence - -^— = - ^ ^ dx dx y where ^ is a constant, the graph o^ ^- to - is a straight line, and dx y the curve of contraction is the i^arabola y'^ Do^ h X, where D„ is O 05 lO 15 -20 -25 -30 Fig. 10. — Gas Transference through Bubbles. Rates plotted with reciprocals of diameters. (1) Black H bubble of constant composition. (2) Golden H bubble of increasing dilution. the initial diameter— a result usually found to be the case. The 121 X. equation of the particular curve in Fig. 6 is y- = 121 But, when a bubble partly composed of glycerine is exposed to water vapour and thereby progressively diluted, then the surface tension will increase ; and' the internal pressure will rise at a greater rate than would be due to diminution of diameter alone. The graph of the rates of gas transference, plotted with the reciprocals of the corresponding diameters, would no longer be a straight line. The next figure (Fig. 10) shows the graphs obtained in the case of (1) bubble 200 Professor Sir James Dewar [Jan. 19, of constant composition, (2) bubble of glycerine solution subjected to absorption of water vapour. In this second case (see also Table 9) the rate of gas transference d D/2 (plotted as abscissas) is increasing more quickly than the inverse of the corresponding diameters 1/D (plotted as ordinates) — a fact which could be explained (1) hj an increase in the surface tension, with a resulting proportional incre- ment in the internal pressure of the contracting bubble : and (2) by a more rapid percolation of hydrogen through the diluted film. It is evident that further comparative experiments are necessary with more dilute films of constant composition before these effects can be differentiated. Preliminary attempts showed that a solution containing only 0*15 per cent, of ammonium oleate with 1 • 5 per cent, glycerine can give a fairly long-lived bulible (one such in hydrogen contracted completely in 2^ days from Professor Sir James Dewar [Jan. 19, change of diameter are observed. The coloured area is seen to change from steel-bhie to bhie-purpl ; through magenta and deep amber until ahnost the whole of it is a full golden colour as a result of the diminished thickness, which however is still of the order of fifteen times that of the l)lack. During this time tlie black bountiary has risen slightly in level ; but when the area of the black zone is calculated at successive stages, the value is found to remain constant to within a few per cent. All liquid must be well drained from the hanging bubble by leaving a drainage tube in contact with the drop position, during the preliminary development to partial blackness. Two sets of observations, showing the approximate con- stancy of the area of the black zone, while the coloured portion is varying to a large ratio. p,ppear in Table 1 0 l)elow. Table 10. Wliole Bubble Black Zont Coloured Zone Diam. (cm.) Area (cm.)2 Area (om.)2 Area (cm.)2 Coloured : Black (i) 17-55 967-6 90-4 877-2 9-7 15-75 779-2 94-5 684-7 7-3 13-70 589-6 94-7 494-9 5-2 11-60 42-2-7 91-1 331-6 3-6 9-54 286-0 84-7 201-3 2-4 (ii) 19-1 1146 77-7 1068-3 13 • 9 16-1 814 76-4 737-6 9-7 131 539 74-5 46i-5 6-2 10-1 302-5 69-1 233-4 3-4 7-1 158 35 • 1 122-9 3-5 Tlius, from the liist four observations, the a the first ))u]}ble only varied some '1 per cent, from its mean ctiij^l l)lack area of value 1)2*7 cm.^, while the coloured-to-l)lack ratio fell from 9*7 to 3 '6, or some 63 per cent. : similarly the actual black aiea of the second bubble varied about 5 per cent, from its mean value 74 ".^ cm.-, while the coloured area fell from nearly 14 times to 3i timei the black area — a drop of over 7.') per cent. Absorption ok Water by Bubbles Oomposed of Oleate ( ; lycerixe Solution. When i)oiled water is introduced into a vessel which liolds a bubble composed })artly of glycerine, water vapour is absorbed and 1917] on Soap Bubbles of Long Duration 203 the normal thinning of the biibl)le to the black stage is prevented. There is instead an increase in thickness, causing gradational changes of colour : the bubble sags down from the increase in weight ; suc- cessive drops accumulate and fall off, at first, maybe, two or three in a day, decreasing rapidly in number as the dilution proceeds, until when the soap-glycerine is reduced to 1 or 2 per cent, the interval between the drops grows into many weeks, and the drainage practically Fig. 11. ceases. When very diluted the black stage is finally reached, and may remain, provided the temperature is steady ; but usually much fluctua- tion of colour takes place, the black even recurring many times. The washings of several such bubbles were collected in a graduated tube, and periodically weighed and analysed. In the case of a bubble of glycerine and ammonium oleate, the analysis for most purposes consisted simply in heating the liquid— in an oven at 90°-95' C.-- until constant in weight. " The contained glycerine and oleic acid 204 Professor Sir James Dewar [Jan. II were thus left practically in the same relative proportions as in the original l)ul)ble, water and ammonia bein^- driven off. If necessary, the ammonia was separately estimated by Nesslerising. This is one advantage attending the use of ammonium oleate in such bul)bles, as compared .with the oleates of a non-volatile base like soda or potash. The arrangements employed are shown in Fig. 11. The l)lo wing- tube A, with its nozzle N to carry the bubble, is supported in an india-rubber cork fitting the neck of a 10 to 12-litre tabulated " aspirator " vessel. D is a bulbed vent tube, and is packed uniformly, 30 DAYS 40 •.ra ' Diameter Fig. 12. — Aie" Bubble ovek Water remains Coloured. Contraction and condensation. but not tightly, with cotton-wool moistened by glycerine. This allows any variations of atmospheric pressure to be equalised with- out endangering the purity of tlie internal atmosphere. B is the graduated collection tube fitted in the lower tubulation ; its nozzle, inside, is directly under the drops whicli accumulate on the l»ul)ble. Before opening the stop-cock on B, to draw off' the accumulated liquid, the stopper in I) is removed to allow the equalisation of barometric pressure, otlierwise the small quantities of liquid could not be smoothly withdrawn ; alternatively, D may remain open. Before commencing observations any excess liquid is removed from the bul)b]e by drainage along the rod 0. This is also done very effectively by a small bundle of very thin irlass rods, about ^ mm. 1917] on Soap Bubbles of Long Duration 205 diameter, tied together bj thin akiminium wire ; but the drawn-out glass rod C acts automatically when placed vertically just below the drop, for, as this grows, it descends by its own weight, and, enveloping the rounded end of the rod, drains down along the drawn-out neck, and the lightened l)ubble rises off the rod. After the bubble has thus drained for several hours, the boiled distilled water is run in. The collecting tube may be utilised for this by turning down the nozzle and tilting the vessel, or a separate inlet tube with stop-cock may be fitted. In order to isolate the bubble from the soap solution in A, and prevent any distillation or intrusion of extraneous liquid, the reservoir in some experiments was removable. For this purpose a conical ground joint was made in the tube A above the india-rubber cork. The contraction of the bubble is somewhat irregular, because of the constantly varying thickness of the film, shown by the beautiful changes and gradings of colour. In the case of an air bubble the contraction is also relatively slow. Thus (Fig. 12) one of 12 cm. diameter only diminished in forty days to 11 cm. A second one, of 21*4 cm. diameter, contracted in five months to 16 '6 cm. A third one, of 15 "8 cm. diameter, took a Uttle over six months to contract to a plane film on the supporting nozzle. In wet hydrogen, however (Fig. I'd), an 11 cm. bubble, — under conditions of somewhat lower temperature, — contracted completely in about three months; almost all this time, moreover, it was of sufficient thickness to show strong colours. The form of the contraction curve of the hydrogen bubble is fairly regular (considering the variations of thickness as shown by the colour changes), and of similar form to that given by black bubbles of constant composition. Its collection curve, of similar type, in which the amounts collected by drainage are plotted as ordinates to the time of collection as abscissae, is also shown in Fig. l:]. Similar contraction and collection curves are shown in Fig. 12 and Fig. 13 for air and hydrogen respectively. The left-hand vertical scales are for cms. in diameter for the contraction curves ; the right- hand scales are for grams of liquid collected for the collection curves. The collection curve appears roughly as an image of the contraction curve, showing that, whereas the contraction is slow at first, increasing parabolically to the final disappearance, the condensation and drain- age begins rapidly when the bubble contains concentrated glycerine, and falls off to zero as the dilution asymptotically approaches completion. Careful measurement of such curves given by both air and hydrogen bubbles revealed them to be parabolic during the initial period before the surface became sensibly reduced by contraction. From this it follows that during this period the rate of collection is inversely as the total amount collected ; just as in the contraction 206 Professor Sir James Dewar [Jau. 19, 1017] on Soap Bubbles of Long Duration 207 curves the rate of diminution of diameter is inversely as the diameter. The equation of tliis first portion of the drainage curve shown in the above figure for a hydrogen bubble is y ^ 0* 1787 ^x, where y is in grams, and x is in days. The approach to agreement between the observed and calculated values thus resulting is seen in the following Table : — Table 11. X Days . . 1 2 3 4 6 8 10 12 U ( Observed . 0-18 0-26 0-305 0-36 0-45 0-52 0-57 0-62 0-66 y gms. 1 Calculated 0-18 0-25 0-309 0-36 0-44 0-51 0-57 0-62 0-67 In half a day 0 * 1 gram of liquid had been collected ; in eight days 0 * 5 gram was obtained ; but a total of 1 * 0 gram was only reached on the 95th day. The corresponding expression in terms of mgms. from each sq. cm. of the bubble surface is «/ = 0'514 aJx, The result given by the bubble under similar conditions in air instead of hydrogen was 2/ = 0-554 V^ (See Fig. 12.) The final composition of the bubble is thus relatively very little different from water. As a confirmation of this the original bubble solution (5 per cent, of ammonium oleate, in 50 per cent, glycerine) was diluted thirty-three times with carefully prepared boiled distilled water. A bubble 8 cm. diameter was then blown from this solution. It lasted until completely contracted after exactly four weeks. During most of this time it was coloured amber to purple ; on three or four of the warmer days nearer the end (temperature about 10° C.) it reached a semi-black stage peculiar to these very dilute bubbles. Only one drop accumulated, caused by the shrinking of the bubble. This bubble has already been referrred to in connec- tion with gas transference through bubbles of graded dilution (see p. 24). By investigating the condensation on unit area of the bubble, instead of on the whole bubble, a simple expression can be found that is applicable to the whole of the drainage curve, instead of only to the initial period of constant surface. The rate per unit area is of course found by dividing the weight of total drainage by the mean surface of the bubble over the period measured. This is most readily done by drawing a succession of tangents, TT', to the collection curve (fig. 13). The slope of these successive tangents along the curve, gives the rates of collection at successive times from the whole bubble surface. The surface each time is obtained from the corre- sponding diameter, obtained by drawing the ordinates 00' to cut the 20^! Professor Sir James Dewar [Jan. 19, contraction curve. By dividing the total daily drainage rate given by the slope of the tangent TT', by the corresponding surface at that time, there results the rate of condensation per unit area. The values thus accruing are set out in the first three horizontal rows of Table 12, with the corresponding day in the fourth row : — Table 12. Daily rate of conden-|Q.Q^gQ.Q3^Q.Q-,^,,gQ.QQgggQ.QQg^Q.QQ^^Q.QQg-^Q.QQ^g sation . . . . j 153-9 0-097 70 Surface 1353 346-3 333-3 314-2 283-5 254-5 227-0 i ' i Kate per unit area X 10*1 13-9 0-895 0-534 0*282 0-226 0-185 0-187 Dav 4 8 14 22 33 43 52 By plotting the third and fourth rows as ordinate and abscissa, a new and more fundamental curve is obtained, which is shown in Fig. 14. An examination of this curve shows that the alteration of the rate of condensation on unit area of the bubble after the fourth day is practically hyperbolic as regards time. The expression most nearly fitting the curve is found (by plotting the results logarithmically) to be xy = 0'705, where x represents the time in days and y the milligrammes of condensation on each square centimetre. Calculated points are marked " x " on the diagram, and values obtained from observations as above are marked " 0." By bursting bubbles in a weighed vessel, it was found that at the mean thickness which these bubbles maintain under the given conditions (shown by their colour) they haye a weight of very approximately 0 • 1 mgm. per square cm., and are therefore 0 • 001 mm. thick. Hence, in the equation just given, y may also represent the weight (in milligrammes) condensed per day on each 0*1 mgm. of the bubble. The resulting values calculated for certain days are set out in the following Table 16^ together mih. the corresponding values obtained directly from the tangents to the original contraction curve : — Table 13. dayi 10 ^co~nd"So'nV'^^^^^^^^^^-^^^^"^^'^-^'^^-^^^ gubbTe'"-1^^--^- lO- 180 0-088 14 0-050 0-058 22 33 43 52 7 0-0320-0210-01600140-( 0-02800230-0190014O-( 1917] on Soap Bubbles of Long Duration 209 The calculated value? are at first too high, but later vary slightly on either side of those directly 'deduced from observations (see Fig. 14). The values in milligrammes per day, of the rate of absorption Fig. 14. — Condensation on Bubble in Wet Hydrogen. Eate of condensation, plotted to time. on unit area with an air bubble 15 1 cm. in diameter, are given in the subjoined Table 14. They were deduced from the weights of liquid collected in the periods named. The composition of the Vol. XXII. (No. ill) p 210 Professor Sir James Dewar [Jail. 19, bubble was 50 per cent, of o-lycerine with 5 per cent, of ammonium oleate. This shows the rapid reduction in the daily rate of con- Table 14. Period 1st day 2-9 „ 10-21 „ 22-34 „ Eatio of Water-vapour Absorption 0-452 0-073 0-014 0-003 densation occurring within a month, — namely, from 0'-152 mgm. .at the beginning down to 0*003 mgm. at the end. Altering Compositiox of the Bubble Drainage. The variation of the composition of the liquid draining from the l)ubble, during the early portion of these experiments, is shown in the next two diao;rams. 10 \—r- r i^-" T— r- H i- l:t J A ^ ^ ^ 1 - «*| ' \\ 1 ~\- t( 8 6 A \j\U.l\\Zi \KJl ^ ^ riir(hpr-?r/ .Sonn-I 0 8 uin uut: ^ -Gly 4--5 cerin.makJ'q X Total. M«n' of origiaal Die ROW washed ; / / / ' bub further O 85% 5oap- - Glycerin, in drainage into drainage. | 0-6 / now dissolved awav 0-4 — P> jb ul )lc 0-2 3- 4-% Soap -Glycerin contained in drainage. 64- m qm* of bubble ■vvra 5Kc d a vxray . z 0 — -c. lO 15 DAYS 20 O 5 Fig. 15.— Altering Composition op Liquid Collected from Bubble WHEN Diluted by Condensation of Water. 16 cm. air bubble ; 55 per cent, soap-glycerine. 1917] on Soap Bubbles of Long Duration 211 Fig. 15 shows the parabolic increase in the weight of the " drainage," with time ; on a separate scale of ordinates, on 'the right-hand side, is marked the multiple of the original bubble weight equal to the amount of liquid collected. The three points marked are : — (1) 0*5 o'l-m. of liquid in 1 dav ; being over 5 " bubble weights." (2) 0-9^,, „ 9 days; „ 10 0-3) 1-0 „ „ 21 „ „ 11 At each of these points the composition of the drainage, as well lOO/o Fig. 16. — Altering Composition of Bubble when Diluted by Condensation of Water. 16 cm. air bubble. as the actual weight of the bubble which had then been washed away, were as follows : — (1) 3*4 per cent, soap-glycerine ; 64 mgms. of original bubble washed away. (2) Further 0*85 per cent, soap -glycerine ; 80 mgms. of original bubble now washed away. (8) Further 0*29 per cent, soap-glycerine ; 86 mgms. of original bubble now washed away. In Fig. 16 the ordinates on the left show the decreasing percentage of soap-glycerine in the bubble, and on the right the consequent increase in the percentage of water, as the experiment proceeded. The 212 Soap Bubbles of Long Duration [Jan. 19, 1917 number of days elapsing- are again marked as abscissae. The dotted ordinate shows, for example, that the laibble on the fifth day had nearly 90 per cent, of the original soap-glycerine replaced by water, and con- sequently only 10 per cent, of the soap-glycerine which was present in the orio^iiial solution then remained ; this was reduced on the fifteenth day to only aljout 3 per cent., but afterwards the rate of dilution was much less. This intrinsic dilution curve agrees in form with that in Fig. 14, which shows the deduced rates of condensation per unit mass (O'l mgm.) of the bubble with time. The one result follows from chemical measures of the alteration of drainage composition, while the other follows from the combined periodical observations of the weight of drainage and the contraction of the bubble. The second part of this investigation dealing with Bubble- Complexes I hope to detail in a future Discourse. W. J. Green, Esq., B.Sc, and J. W. Heath, Esq., F.C.S., Assistants of the Royal Institution, have aided in the course of the enquiry. [J. D.] LONDON : PIUNTKU BY WILLIAM CLOWES ANI> SONS, LIMITED, GKEAT WINDMILL STREET, W.l, AND DUKE STBEET, STAMFORD STREET, S.R.I PROCEEDINGS OF THE Royal Institution of Great Britain Vol. XXII.— Part II. No. 112 Jan. IS. Jan. 25. Feb. 1. Feb. 4. Feb. 8. Feb. 15. Feb. 22. March 1. March 4. March 8. March 15. March 22. April 8. April 12. April 19. April 26. May 1. Ma}^ 3. May 6. i\Iay 10. May 17. May 24. May 31. June 3. June 7. July 1. Nov. 4. Dec. 2. 1918 Professok Sib James Dewar — Studies on Liquid Films Professor John S. Townsend — The Motion of Ions in Gases Professor A. S. Eddington — Gravitation and the Principles of Relativity General Meeting Principal E. H. Griffiths — Science and Ethics Professor W. Bateson — Gamete and Zygote Arthur Clutton-Brock — The Importance of Art Professor A. G. Green — The Modern Dye-Stufi Industry ... General Meeting ... ' Professor Edwin H. Barton — Vibrations : Mechanical, Musical and Electrical Rt. Rev. Boyd- Carpenter — The Romantic Movement Professor Sir J. J. Thomson — Radiation from System of Electrons ... General Meeting Professor E. C. C. Baly — Absorption and Phosphorescence Major G. I. Taylor — The Use of Soap Films in Engineering Sir J., A. Daniel HalL — Food Production and English Land Annual Meeting Sir George Greenhill— The Spinning-Top in Harness General Meeting Professor F. Gowland Hopkins — The Scientific Study of Human Nutrition Alfred Barton Rendle — The Story of a Grass LiEUT.-CoL. A. G. Hadcock — Internal Ballistics Laurence Bin yon— Poetry and Modern Life General Meeting ... Sir Boverton Redwood— The Romance of Petroleum General Meeting General Meeting General Meeting PAQB 859 213 215 232 235 236 240 240 241 243 260 358 273 275 276 277 285 286 296 358 300 303 310 326 329 349 351 355 ALBEMAELE STREET, LONDON, W.l 1922 WEEKLY EVEXIXG MEETING, Friday, Januarv 25, 1918. Sir William Phipsox Beale, Bart., K.C. M.P., Vice-President, in the Chair. Peofessor Johx S. Towxsexd, F.Pi.S. The Motions of Ions in Gases. Whex ions move in a gas under an electric force, and the sizes of the ions are unaffected either by changes of force or of pressure, the velocity of the ions in the direction of the force is proportional to the ratio of the force to the pressure (X/P), provided the velocity in the direction of the force is small compared with the velocity of agitation of the ions. For small values of the ratio X/P the ions move as if they were associated with masses which are large compared with the masses of the molecules of the surrounding gas, and the kinetic energy of the motion of agitation of the ions is equal to that of the molecules with which they collide. When the pressure is reduced the mobility of the negative ions increases with the force, which shows that the mass associated with each ion diminishes as the force increases. Experiments were described from which it was shown that at a certain point, depending on the ratio X/P, the electrons move freely through the gas, as the ratio of the charge e to the mass m of the electrified particle was found to be approximately the same as the value 5 • 6 X 10^'' for electrons moving in a highly exhausted space. Thus in dry air at a pressure of 18 millimetres of mercury the electrons move freely, unassociated with larger masses, when the force is 3 or 4 volts per centimetre. A similar result is obtained at higher pressures by increasing the force. When a small quantity of water vapour is present in the gas a larger force is required to attain the point at which the electrons move freely, which shows that the electrons have a greater tendency to adhere to molecules of water vapour than to molecules of oxygen or nitrogen. In all cases the electronic state is attained with much smaller forces than those required to produce ions by collisions with molecules. The latter effect, for example, could not be easily detected in air at 18 millimetres pressure unless the force exceeded 30 volts per centimetre. The experiments show that while the mass associated with the electron undergoes these changes the charge remains constant. Vol. XXII. (No. 112) ^ q 214 The Motions of Ions in Gases [Jan. 25, It was also found that after the transition stage from the large to the small mass, the velocity of agitation of the electrons is much larger than the velocity corresponding to that of a particle of equal mass in thermal equilibrium with the surrounding gas. The latter velocity is approximately 10^ centimetres per second, whereas the velocity of agitation of the electrons is l'6xlO^ centimetres per second in dry air, when X/P = 0 ' 2. This velocity increases with the force and is 10^ centimetres per second, when X/P = 50. The velocity of agitation of the electrons is easily deducted from observations on the lateral diffusion of a stream of particles moving through the gas under an electric force. The spreading of the stream is independent of the pressure of the gas, and has a definite normal value depending on the force when the kinetic energy of agitation of the ions or electrons is equal to that of the surrounding molecules. When the pressure is reduced below a certain value, which is propor- tional to the force, the lateral diffusion becomes abnormally large, which can only be due to an increase in' the velocity of agitation of the electrons. This result* shows that the electrons tend to retain the velocity they acquire under the electric force, and the principal effect of a collision with a molecule is not to reduce the velocity of an electron, but only to alter its direction of motion. This action continues until a steady state is attained in which the motion of agitation is so large that the loss of energy by collisions is equal to the energy acquired under the electric force. [J. S. T.] Proc. Roy. Soc, 1908, A, 81, p. 464. 1918] Gravitation and the Principle of Relativity 215 WEEKLY EVENING MEETING, Friday, February 1, 1918. J. H. Balfour Browne, K.C. LL.D., Vice-President, in the Chair. Professor A. S, Eddington, F.R.S. Gravitation and the Principle of Relativity. There were many difficulties to encounter in entering the room just now. To begin with, we had to bear the crushing load of the atmosphere, amounting to 14 lbs. on every square inch. At each step forwards, it was neaessary to tread gingerly on a piece of ground moving at the rate of 20 miles a second on its way round the sun. We were poised precariously on a globe, apparently hanging by our feet, head outwards into space. And this acrobatic feat was performed in the face of a tremendous wind of ether, blowing at I do not know how many miles a second literally through us. We do not claim much credit for overcoming these difficulties — because we never noticed them. But I venture to remind you of them, because I am about to speak of some other extraordinary things that may be happening to us of which we are quite unconscious. Not to go too far back in history, the present subject arises from a famous experiment performed in the year 1887, known as the Michelson-Moiiey experiment. The apparatus was elaborate, but the principle of the experiment is not very difficult. If you are in a river, which will be the quicker — to swim to a point 50 yards up stream and back again, or to a point 50 yards across stream and back again ? Mathematically the answer is, perhaps, not immediately obvious, because the net effect of the current is a delay in both cases. But I think that anyone who has swum in a river will have no hesitation about the answer. The up-and-down journey takes longer. Now we are in a river —of ether. There is a swift current of ether flowing througn this room ; or, if we happen to be at rest in the ether at the present moment, six months hence the earth's orbital motion will be reversed, and then there must be a swift current. Michelson divided a beam of light into two parts ; he sent one half swimming up the stream of ether for a certain distance, and then by a mirror back to the starting-point ; he senl the other half an equal distance (as he thought) across the stream and back. It was a race ; and with his apparatus he could test very accurately which part got bacii first. To his surprise, it was a dead-heat. Clearly the two paths could not really have been eqaal, the along-stream path must have been a little Q 2 216 Professor A. S. Eddington [Feb. 1, shorter to compensate for the greater hindrance of the current. That objection was foreseen, and the apparatus, which was mounted on a stone pier floating in mercury, was rotated through a right angle, so that the arm whicli was formerly along the stream was now across the stream, and vice versa. Again, the two portions of the beam arrived at the same moment ; so this time the other arm bad become the shorter— simpl J by altering its position. In fact these supposedly rigid arms had contracted when placed in the up-and-down stream position by just the amount necessary to conceal the effect which was looked for. That is the plain meaning of the experiment ; but we might well hesitate to accept this straightforward interpretation, and try to evade it in some way, were it not for s<>me theoretical discoveries made later. It has gradually appeared that matter is of an electrical nature, and the forces of cohesion between the particles, which give a solid its rigidity, are electrical forces. Larmor and Lorentz discovered that this property of contraction in the direction of the ether current was something actually inherent in the formula for electrical forces written down by Maxwell many years earlier and universally adopted ; it only waited for some mathematician to recognize it. It would be going too far to say that Maxwell's equations actually prove that contraction must take place ; but they are, as it were, designed to fall in line with the contraction phenomenon, and certain details left vague by Maxwell have since been found to correspond. We are then faced with the result that a material body experi- ences a contraction in the direction of its motion through the ether. According both to theory and experiment the contractioji is the same for all kinds of matter— a universal property. One reservation should be made ; the experiment has only been tried with solids of labora- tory dimensions, which are held together by cohesion. There is at present no experimental evidence that a body such as the earth whose form is determined by grcivitation will suffer the same contraction ; we shall however assume that the contraction takes place in this case also. I am going to ask you to suppose that we in this room are travelling through the ether at the rate of 161,000 miles a second, vertically upwards. Let us be bolder and say that that is our velocity through the etht^r — because no one will be able to contradict us. No exjjeriment yet tried can detect or disprove that motion ; Ijecause all such experiments give a null result, as the Michelson-^Iorley experi- ment did. With that speed the contraction is just one-half. This pointer, which I hold horizontally, is 8 feet long. Now [turning it vertically] it is 4 feet long. But, you may say, it is taller than I am, and I must l-e approaching 6 feet. No, if I lay down on the floor I sh-^uld be, but as I am standing now I am under 8 feet. The con- traction affects me just as it did the pointer. It is no use bringing a standard yard-measure to measure me, because that also will con- 1918] on Gravitation and the Principle of Relativity 217 tract and represent only half a yard. " But we saw that the pointer did not change length when it turned." How did you tell that ? What you perceived was an image of the pointer on the retina of your eye, and you thought the image occupied the same space of retina in both positions ; but your retina has also contracted in the vertical direction without your knowing it, so that your estimates of length in that direction are double what they should be. And similarly with every test you could apply. If everything undergoes the same change, it is just as though there were no change at all. We thus get a glimpse of what from our present point of view must.be called the real world, strangely different from the world of appearance. In the real world, .by changing position you extend yourself like a telescope ; and the stoutest individual may regain slimness of figure by an appropriate orientation. It must be some- thing like what we see in a distorting mirror ; and you can almost see a living-picture of this real world reflected in a polished door- knob. If our speed through the ether happens not to be so great as we have supposed, the contraction is smaller ; but it escapes notice in our practical life, not because it is small, but because from its very nature it is undetectable. And because this real world is undetect- able we do not as a rule attempt to describe it. Not merely in every- day life, but in scientific measurements also, we describe the world of appearance. We do this by imagining natural objects to be placed, not in the absolute space, but in a quite different framework of our own contriving — a space which corresponds to appearance. In the space of appearance a rod does not seem to change length when its direction is altered ; and we use thab property to tjlock out our con- ventional space, counting the length occupied by the standard yard- measure as always a yard however its true length may vary. It is found also that in like manner our time is a special time of our own, different from the time we should adopt if our motion through the ether were nil. Tliis is a perfectly right procedure ; it intro- duces no scientific inexactness, and it is more in accordance with the ordinary meaning attached to space and time ; the only thing to remember is that this space and time framework is something peculiar to us, defined by our mctiin, and it has not the meta- physical property of absoluteness, which we have often unconsciously attributed to it. Xow let us visit for a moment the star Arcturus, which is moving relatively to us with a velocity of over 200 miles per second. Con- sequently its motion through the ether is different from ours, and the contraction of objects on it will be different. It follows that our conventional space would not be suitable for Arcturus, because it was specially chosen to eliminate our own contraction effects. There is a different space and a different time proper to Arcturus. We must then imagine each star carrying its own appropriate space 218 Professor A. S. Eddington [Feb. 1, and time according to its motion tlirouo-b the etlier. The space and time of one stai- will not fit the experience of individuals on another star. The exact relation between the appropriate space and time of one star and the space and time of another was first Ijrought out clearly by Minkowski ; it is a very remarkable one. We recognize three dimensions of space, which we may take as up-and-down, right-and-left, backwards-and-forwards. If we go over to Ireland we still have the same space, but Ireland's up-and-dow^n no longer corresponds to ours. The directions are inclined ; and what is vertical to them is partly vertical and partly horizontal to us. Now lee us add a fourth dimension, imaginary* time, at right angles to the other three. There is no room for it in the model, but we must do our best to imagine it in four dimensions. In Ireland the three space-dimensions will have rotated, as I have said ; but the time will be just the same. But if we go to Arcturus, or to any body moving with a velocity different from our own, the time- dimension also has rotated. What is time to them is partly time and partly imaginary space to us. It is a change in the space-time world of four dimensions just analogous to the change in the space-world between liere and Ireland. That is Minkowski's great result ; space- time is the same universally, but the orientation — the resolution into space and time separately — depends on the motion of the individual experiencing it, just as the resolution of space into horizontal and vertical depends on his situation. In Minkowski's own famous words—" Henceforth Space and Time in themselves vanish to shadows, and only a kind of union of the two preserves an inde- pendent existence." From our original point of view it seems very remarkable that in the Miche'son-Morley experiment the contraction should Lave been of just the right amount to annul the expected effect of our motion through the ether. Many other experiments, which seemed likely to show such an effect, have been tried since then, but in all of them the same kind of compensation takes place. It looks as though all the forces of nature had entered on a conspiracy together with the one design of preventing us from measuring or even detecting our motion through the ether. It is still an open question whether one force, the force of gravitation, has joined the conspiracy. Hitherto gravitation has stood aloof from all the other interrelated phenomena in majestic isolation. We have become almost reconciled to leaving it outside every physical theory. A new model of the atom is put forward which accounts for a whole host of abstruse and recently discovered properties ; but it would l)e considered unfair to suggest that it ought to account for the simple and universal property of gravitation. Dare we think that gravitation has so far forgotten its Imaginary in the mathematical sense, i.e. involving V - 1. 1918] on Gravitation and the Principle of Relativity 219 dignity as to join this conspiracy ? There is certainly not enough evidence for a jury to convict ; but yet I think we shall have to intern it on suspicion. Recently Sir Oliver Lodge, believing that gravitation was innocent of the conspiracy, showed that a very famous astronomical discordance in the motion of Mercury miirht be an effect due to the sun's motion through the ether, and might afford a means of estimating its speed. It is difficult in a brief reference to deal quite fairly with an intricate question, but it seems now tliat we should rather lay stress, not on this single discordance, which can perhaps be otherwise explained, but on the exact agreement of Yenus and the Earth with theory ; for they also should show evidence of the sun's motion through the ether if gravitation had not joined in the conspiracy to conceal all such effects. It may be that the effects on Venus and the Earth are not found because the sun's motion through the ether happens to be very small ; but on the whole it appears more likely that the effect of the motion is null, just as in the Michelson-Morley experiment, because there is a complete compensation in the law of gravitation itself. The great advantage of Minkowski's point of view is that it gets rid of all idea of a conspiracy. You cannot have a conspiracy of con- cealment when there is nothing to conceal. We cut Minkowski's space-time world in a certain direction, so as to give us separately space and time as they appear to us. AVe have been imagining that there exists some direction which would separate it into a real and absolute space and time. But why should there be ? Why should one direction in this space-time world be more fundamental than any other ? We do not attempt to cut the space-world in a particular direction so as to give us the reaJ horizontal and vertical. The ^-ords horizontal and vertical have no meaning except in reference to a particular spot on the earth. So for a particular observer th3 space- time world falls apart into its four components, up-and-down, right- and-left-, backwards-and-f or wards, sooner-and -later ; but no observer can say that this division is the one and only real one. Our idea of a real space more fundamental than our own was, h )W- ever, not entirely metaphysical ; we had materialized it by filHng it with an ether supposed to be at rest in it. We now deny the existence of any unique framework of that kind. We have failed to obtain experimental knowledge of such a framework since we cannot detect our motion relative to it. Whatever may be the nature of the ether, it is. devoid of those material properties which could constitute it a framework of reference in space. We can perhaps best picture the ether as a four-dimensional fluid filling uniformly Minkowski's space- time continuum, not as a material three-dimensional fluid occupying space and time independently. The position we have now reached is known as the Principle of Relativity. In so far as it is a physical theory, it seems to be amply confirmed by numerous experiments (except in regard to gravitation). 220 Professor A. S. Eddington [Feb. 1, In so far as it is a philosophical theory, it is no more than a legitimate and useful point of view. I now pass on to a Generalized Principle of Relativity, in which we must be content at first: to be guided by a natural generalization of these results, hoping later to be able to check our tentative conclusions by experiment. If we analyze any scientific observation, distinguishing between what we perceive and what we merely infer, it always resolves itself into a coincidence in space and time. A physicist states that he has observed that the current through his coil is 5 milliamperes ; but what he actually saw was that the image of a wire thrown by his galva- nometer coincided with a certain division on a scale. He measures the temperature of a liquid, but the observation is the coincidence of the top of the mercury with a division on the thermometer. If then we had to sum up the whole of our experimental knowledge, we should have to describe it as consisting of a large number of coincidences. A complete history of the progress of a particle consists of a knowledge of its path and the time at which it occupied each point of the path. The time may be regarded as an extra co-ordinate corresponding to a fourth dimension, and so the whole history may be summed up by a line in four dimensions representing the particle's progress through space and time. We call this four-dimensional Hue the world-line of the particle. Imagine that we have drawn the world-lines of all the particles, light-waves, etc., in the universe ; we shall then have a complete history of the universe. It will be rather a dull history-book ; the Venus of Milo will be represented by an elaborate schedule of measurements, and Monna Lisa by a mathe- matical specification of the distribution of paint ; still they are there, if only we can recognize them. I have here a history of the universe — or part of it. Unfortunately I was not able to draw it in four dimensions, and even three dimensions presented difficulties, so I have drawn the world-lines in two dimensions on the surface of a football bladder. A great deal is shown here which properly speaking is not history at all, because it is necessarily outside experience. As we have seen, it is only coincidences — the intersections of the world-lines — that constitute observational knowledge ; and, moreover, it is not the place of intersection but the fact of intersection that we observe. I am afraid the tAvo-dimensional model does not give a proper idea of this, because in two dimensions any two lines are almost bound to meet sooner or later ; but in three dimensions, and still more in four dimensions, two lines can and usually do miss one another altogether, and the observation that they do meet is a genuine addition to knowledge. When I squeeze the bladder the world-lines are bent about in different ways. But I have not altered the history of the universe, because no intersection is created or destroyed, and so no observable event is altered. The deformed bladder is just as true a history of 1918] on Gravitation and the Principle of Relativity 221 nature as the undeformed bladder. The bladder represents Min- kowski's space-time world, in which the world-lines were drawn ; so we can squeeze Minkowski's world in any way without altering the course of events. We do not usually use the vulgar word squeeze ; we call it a mathematical transformation, but it means the same thing. The laws of nature in their most general form must describe correctly the behaviour of the world-lines in either the undistorted or the distorted model, because it is indifferent which we take as the .true representation of the course of nature. That is a very important principle ; but, being almost a truism, it does not in itself help us to determine the laws of nature without making some additional hypothesis. There is one law— the law of gravitation — which especially attracts our attention at this point, and we shall look into it more closely. We know that one particle attracts another particle, and so influences the history of its motion. This evidently means that one world-line will deflect any other world-line in its neighbourhood. Apart from this influence, the world-line runs straight, bending neither to the right nor to the left, provided the bladder is in its undistorted state, i.e. provided we use Minkowski's original space- time. That is not so much a matter of observation as of definition. It defines what we are to regard as the undistorted state, though it is by observation that we learn that it is possible to find a space-time in which the world-lines run straight when undisturbed by gravita- tional or other forces. I must own that there is a certain logical difficulty in saying that a world-line runs straight when there are no others near it ; because in that case there could be no inter- sections, and we could learn nothing about its course by observation. However, that is not a serious difficulty, though you may be reminded of the sage remark, " If there were no matter in the universe, the law of gravitation would fall to the ground." We have to admit, then, that a world-line can be bent by the proximity of other woild-lines. It can also be bent, as you see, by the proximity of my thumb. The suggestion arises, may not the two modes of bending be essentially the same ? The bending by my thumb (a mathematical transformation of space and time) is in a sense spurious ; the world-line is pursuing a course which is straight relative to the original material. Or we may perhaps best put it this way— the world-line still continues to take the shortest path between two points, only it reckons distance according to the length that would be occupied in the unstretched state of the bladder. It is suggested that the deflection of a world-line by gravitation is of the same nature ; from each world -line a state of distortion radiates, as if from a badly puckered seam, and any other world-line takes the shortest course through this distorted region, which would immediately become straight if the strain could be undone. The 222 Professor A. S. Eddington . [Feb. 1, same rule -of shortest distance as measured in the uudistorted state — is to hold ill all cases. This is a mode of reasoning which has often been fruitful in scientific g'eneralizations. A magnetic needle turns towards the end of a bar-magnet ; it also turns towards a spot near the pole of the earth ; hence the suggestion that the earth is a magnet. AVe assume the essential identity of the two modes of deflecting the needle. It is a daring step to apply the analogy, and assume the essential identity of the two \yays of deflecting world-lines ; but at any rate we shall make this assumption and see what comes of it. You will see that according to this view^ the earth moves in a curved orbit, not because the sun exerts any direct pull, but because the earth is trying to find the shortest way through a space and time which have been tangled up by an influence radiating from the sun. AVe can continue to describe this indirect influence of the sun on the earth's motion as a " force " ; but, assuming that it makes itself felt as a modification or strain of space and time, we are able to bring the discussion of the laws of this force into line with the discussion of the laws of space and time, i.e. the laws of geometry. Needless to say we could not determine a physical law^ like the law of gravitation by geometrical reasoning without making some assumption. I am afraid that to talk of a force as being a distortion of space and time must at first appear to you hopeless jargon. But it must be remembered first that we are not concerned with any metaphysical space and time. We mean by space and time simply a scaffolding that we construct as the result of our measures ; and if anything queer happens to our measuring apparatus, the scaffolding may easily go crooked. Taking our everyday conception of space, we should say that this room is at rest ; we have been told that it is being carried round the earth once a day, but in practical life we never pay any attention to that. The space that we naturally use is thus different from, and it is not difficult to show that it is distorted as compared Ayith, the more fundamental astronomical space in which this room is travelling at a great velocity. So our scaffolding is crooked. But, it may be asked, in Avhat way can this distortion of our space-scaffolding be regarded as a force ? The answ^er is quite simple. We perceive it as a force, and that is the only way in which we do perceive it. We do not perceive that this room is being carried round by the earth's rotation, but we perceive a certain force — the earth's centrifugal force. It is rather difficult to demonstrate this force, because graviation predominates overwhelmingly ; but if gravity were annihilated we should have to be tied down to the floor to pre- vent our flying up to the ceiling, and we should certainly feel our- selves pulled i:)y a very vigorous centrifugal force. That is our only perception of the crookedness of our scaffolding. We often call the centrifugal force an " unreal " force, meaning that it arises simply from a transformation of the framework of referf.nce. Can we feel confident that gravitation is in any sense 191S] on Gravitation and the Principle of Relativity 228 more "real " ? In effect tliev are so much alike iliat even in scien- tific work we speak of tlieni in one hreatli. What is called the value of gravity in London, 1)81 -17 cm. /sec-, is really made up partly of the trae attraction of the earth and partly of the centrifugal force. It is not considered worth while to make any distinction. Surely, then, it is not a great stretch of the imagination to regard gravitation as of the same nature as centrifugal force, being merely our percep- tion of the crookedness of the scatfoMing that we have chosen. If gravity and centrifugal force are manifestations of the same underlying condition it must l)e possible to reduce them to the same laws ; but we must express the laws in a manner which will render them comparable. There is a convenient form of Newton's law, which was given by Laplace and is \\ell known to mathematicians, which describes how the intensity at any point is related to the intensity at surrounding points — or, according to our interpretation, how the distortion of space at any point fits on to the distortion at surrounding points. It is evidently an attempt to express the general laws of the strains in space and time which occur in nature. If we are correct in our assumption that gravitation involves nothinfj more than strain of space-time," so that its law expresses merely the rela- tion between adjacent strains which holds by some natural necessity, clearly the strains which give the centrifugal force must obey the same general law\ Here a very interesting point arises. We cannot reconcile the Newtonian law of gravitation with this condition. Newton's law and the law of centrifugal force are contradictory. To put the matter another way, if we determine the strains by Newton's law, we get results closely agreeing with observation^ pro- vided Minkowski's space-time is used ; but if we avail ourselves of our right to use a transformed space -time, the results no longer agree vrith observation. That means that Newton's law involves sometliing which is not fully represented by strains, and so does not agree ^7ithour assumption. We must either abandon our assumption, or abandon the famous law which has been accepted for over 200 years, and find a new law of gravitation which will fall in with our requirements. This amended law has been found by Einstein, It appears to be the only possible law that meets our requirements, and in the limited applications which come under practical observation is suffi- ciently close to the old law that has served so well. In practical applications the two laws are indistingtiishable, except for one or two crucial phenomena to which reference will be made later. Bat in gravitational fields far stronger than any of v;hich we have experi- * The idea is that matter represents a seam or nucleus of strain, and the strains at other points link themselves on according to laws inherent in the continuum Q.ndi quite independent of the matter. The matter starts the strain, but does not control it as it goes outwards. 224 Professor A. S. Eddington [Feb. 1, ence, and for bodies moving with velocities much greater than those of the planets, the difference would be considerable. This idea of the distortion of space as the modus operandi of gravitation has led to a practical result — a new law of gra\'itation. It is not brought in as a hypothetical explanation of gravitation ; if Einstein's theory is true, it is simply of the nature of an experimental fact. If we draw a circle on a sheet of paper and measure the ratio of the circumference to the diameter, the result gives, if the experiment is performed accurately enough, the well-known number -, which has been calculated to 707 places of decimals. Now place a heavy particle at or near the centre and repea,t the experiment ; the ratio will be not exactly equal to tt, but a little more. The experiment has not been performed, and is not likely to be performed, because the difference to be looked for is so small ; but, if Einstein's theory is correct, that must be the result. The space around the heavy particle does not obey ordinary geometry ; it is non-Euclidean. The change in its properties is not metaphysical, but something which with sufft- cient care could be measured. You can keep to Euclidean space if you like, and say that the measuring-rod has contracted or expanded according as it is placed radially or transversely to the gravitational force. That is all very well if the effect is small, but in a very intense gravitational field it would lead to ridiculous results like those we noticed in connection with the Michelson-Morley experiment — everything expanding or contracting as it changed position, and no one aware of any change going on. I think we have learnt our lesson that it is better to be content with the space of experience, whether it turns out to be Euclidean or not, and to leave to the mathematician the transformation of the phenomena into a space with more ideal properties. This consequence of the new law of gravitation, though theo- retically observable, is not likely to be put to any practical test either now or in the immediate future. But there are other consequences which just come within the range of refined observation, and so give an immediate practical importance to the new theory, which has indeed scored one very striking success. If we could isolate the sun and a single planet, then under the Newtonian law of gravitation the planet would revolve in an ellipse, repeating the same orbit indefinitely. Under the new law this is not quite true ; the orbit is nearly an ellipse, but it does not exactly close up. and in the next revolution the planet describes a ncAv ellipse in a slightly advanced position. In other words, the elliptic orbit slowly turns round in the same direction in which the planet is moving, so that after the lapse of many centuries the orbit will point in a different direction. The rate at which the orbit turns depends on the speed of motion of the planet in its orbit, so we naturally turn to the fastest moving planets, Mercury, Venus and the Earth, to see if the 1918] on Gravitation and the Principle of Relativity 225 effect can be detected. Mercury moves at 30 miles a second ; Venus at 22 ; the Earth at 18J. But there is a difficulty about Venus and the Earth. Their orbits are nearly circular, and you cannot tell in which direction a circle is pointing. Mercury combines the favour- able conditions of a high speed and a satisfactorily elongated orbit ^\hose direction at any time can be measured with considerable precision. It is found by observation that the orbit of Mercury is advancing at the rate of 574 seconds of arc a century. This is in great measure due to the attraction of the other planets, which are pulling the orbit out of shape and changing its position. The amount of this influence can be calculated very accurately, and amounts to 532 seconds per century. There is thus a difference of 42 seconds a century unaccounted for ; and this has for long been known as one of the most celebrated discordances between observa- tion and gravitational theory in astronomy. It is thirty times greater than the probable error which we should expect from uncertainties in the observations and theory. There are other puzzling discordances, especially in connection with the motion of the moon ; but the conditions in that case are more complicated, and I scarcely think they offer so direct a challenge to gravitational theory. Now Einstein's theory predicts that there will be a rotation of the orbit of Mercury additional to that produced by the action of the planets ; and it predicts the exact amount — namely, that in one revolution of the planet the orbit will advance by a fraction of a revolution equal to three times the square of the ratio of the velocity of the planet to the velocity of light. We can work that out, and we find that the advance should be 43 seconds a century — just about the amount required. Thus whilst the Newtonian law leaves a discordance of over 40 seconds, Einstein's law agrees with observa- tion to within a second or so. Of course this superiority would be discounted if we could fiud some other application where the old Newtonian law liad proved the better. But that has not happened. In all other cases the two laws agree so nearly that it has not been possible to discriminate between them by observation. The new law corrects the old where the old failed, and refrains from spoiling any agreement that already exists. The next best chance of applying the new theory is in the advance of the orbit of Mars ; here Einstein's new law "gilds refined gold " by slightly improving an agreement which was already sufficiently good — a " wasteful and ridiculous excess " which is at any rate not un- favourable to the new theory. There is another possibility of testing Einstein's theory, which it is hoped to carry out at the first opportunity. This relates to the action of gravitation on a ray of light. It is now known that electro- magnetic energy possesses the property of inertia or mass, and probably the whole of the mass of ordinary matter is due to the electromagnetic energy which it contains. Light is a form of electromagnetic energy, 22(5 Professor A. S. Eddington [Feb. 1, and therefore must have mass — ^a coiickision which has ])een found true experiraeiitally, because light falhng on any object exerts a pressure just as a jet of water would. We ordinarily measure mass in pounds, and it is quite proper to speak of " a pound of light," just as we speak of a pound of tobacco. In case anyone should be thinking of s'oing to an Electric Light Company to buy a pound of light, I had better warn you that it is a rather expensive commodity. They usually prefer to sell it by a mysterious measure of their own, called the Board of Trade Unit, and charge, at least, threepence a unit. At that rate I calculate that they would let you have a pound of light for £141,615,000. Fortunately, we get most of our light free of charge, and tlie sun showers down on the earth 160 tons daily. It is just as well we are not asked to pay for it. But although light has mass, it does not follow that light has weight. Ordinarily, mass and weight are associated in a constant proportion, but whether this is so in the case of light can only be settled by experiment — by weighing light. It seems that it should be just possible to do this. If a beam of light passes an object which exerts a gravitational attraction, then, if it really has weight, it mutt drop a little towards the object. Its path will be bent just as the trajectory of a rifle bullet is curved owing to the weight of the bullet. The velocity of light is so great that there is only one body in the solar system powerful enough to make an appreciable bend in its path, namely, the sun. If we could see a star close up to the edge of the sun, a ray of light coming from the star would l)end under its own weight, and the star would be seen slightly displaced from its true position. During a total eclipse stars have occasionally been photographed fairly close to the sun, and with care it should be possible to observe this effect. There is a magnificent opportunity next year when a total eclipse of the sun takes place right in the midst of a field of bright stars. This is the best opportunity for some generations, and it is hoped to send out expeditions to the line of totality to weigh light according to this method. In any case great interest must attach to an attempt to settle whether or not light has weight. But there is an additional impor- tance, because it can be made a means of confirming or disproving Einstein's theory. On Einstein's theory light must certainly have weight, because mass and weight are viewed by it as two aspects of the same thing ; but his theory predicts a deflection twice as great as we sliould otherwise expect. Apart from surprises, there seem to be tliree possible results : (1) a deflection amounting to 1*75" at the limb of the sun, which would confirm Einstein's theory ; (2) a de- flection of 0*83" at the limb of the sun, which would overthrow Einstein's theory, but would estaljlish that light was subject to gravity ; (3) no deflection, which would sliow that light though possessing mass has no weight, and hence that Newton's law of pro- portionality between niass and gravitation lias broken down in another unexpected direction. 1918] on Gravitation and the Principle of Relativity 227 The purpose of Einstein's new theory has often been misunder- stood, and it has been criticized as an attempt to explain gravitation. The theory does not offer any explanation of gravitation ; that lies quite outside its scope, and it does not even hint at a possiVjle mech- anism. It is true that we have introduced a definite hypothesis as to the relation between gravitation and a distortion of space; but if that explains anything, it explains not gravitation but space, i.e. the scaffolding constructed from our measures. Perhaps the position reached may be made clearer by another analogy. Let us picture the particle which describes a world-line as hurdle-racer in a field thickly strewn with hurdles. The particle in passing from point to point always takes the path of least effort, crossing the fewest possible hurdles ; if the hurdles are uniformly distributed, corresponding to undistorted Minkowskian space, this will, of course, be a straight line. If the field is now distorted by a mathematical transformation such as an earthquake so that the hurdles become packed in some parts and spread out in others, the path of least effort will no longer be a straight line ; but it is not difficult to see that it passes over precisely the same hurdles as bei^ore, only in their new positions. The gravitational field due to a particle corresponds to a more funda- mental rearrangement of the hurdles, as though someone had taken them up and replanted them according to a -law^ which expresses the law^ of gravitation. Any other particle passing through this part of the field follow^s the guiding rule of least effort, and curves its path if necessary so as to jump the few^est hurdles. Now, we have usually been under the impression that when we measured distances by physical experiments we were surveying the field, and the results could be plotted on a map ; but it is now realized that we cannot do that. The field itself has nothing to do with our measurements ; all we do is to count hurdles. If the only cause of irregularity of the hurdles were earthquakes (mathematical transformations) that would not make much difference, because we could still plot our counts of hurdles consistently as distances on a map ; and the map would represent the original condition of the field with the hurdles uniformly spaced. But the more far-reaching rearrangement of hurdles by the gravitational field forces us to recognize that we are dealing with counts of hurdles and not with distances ; because if we plot our measures on a map they will not close up. The number of hurdles in the circumference of a circle * will not be tt times the number in the diameter ; and when we try to draw on a map a circle whose circumference is more than tt times its diameter, we get into difficulties— at least in Euclidean space. This * A circle would naturally be defined as a curve such that the number of hurdles (counted along the path of least effort) between any point on it and a fixed point called the centre is constant. To make the vague analogy more definite, we may suppose that the hurdles are pivoted, and swing round auto- matically to face the jumper ; he is not allowed to dodge them, i.e. to introduce into his path sinuosities comparable with the lengths of the hurdles. 228 Professor A. S. Eddington [Feb. 1, analogy brings out the point that the theory is an explanation of the real nature of our measures rather than of gravitation. We offer no explanation why the particle always takes the path of least effort— perhaps, if we may judge by our own feelings, that is so natural as to require no explanation. More seriously, we know that in consequence of the undulatory theory of light, a ray traversing a heterogeneous medium always takes the path of least time ; and one can scarcely resist a vague impression that the course of a material particle may be the ray of an undulation in five dimensions. What concerns gravita- tion more especially is that we have offered no explanation of the linkages by which the hurdles rearrange themselves on a definite plan when disturbed by the presence of a gravitating particle ; that is a point on which a mechanical theory of gravitation ought to throw light. From the constant of gravitation, together with the other fundamental constants of nature— the velocity of light and the quantum of action — it is possible to form a new fundamental unit of length. This unit is 7 x 10"-^ centimetres. It seems to be inevitable that this length must play some fundamental part in any complete interpretation of gravitation. (For example, in Osborne Reynold's theory of matter this length appears as the mean free- path of the granules of his medium.) In recent years great progress has been made in knowledge of the excessively minute ; but until we can appreciate details of structure down to the quadrillionth or quintillionth of a centimetre, the most suVjlime of all the forces of nature remains outside the purview of the theories of physics. [A.S.E.] APPENDIX. Outline of the Mathematical Theory of Einstein's Law OF Gravitation. The fundamental formula, by which from measurements we infer the relative positions of objects in a space defined by three rectangular co-ordinates, x, y, z, is — ds- = dx" -h dy"- 4- dz"- (1) where ds is the measured element of length, and the right-hand side refers to the inferred positions. Experiments are concerned with fields of gravitation which from the present point of view must be regarded as extremely weak, so the formula must be taken as applying strictly only in the absence of gravitation. (We have no proof that in a strong gravitational field the formula would be self-consistent, i.e. that measured space would be Euclidean.) l'.>18] on Gravitation and the Principle of Relativity 221) In four dimensions, the formula is generalized to — rW = dx- + dif + dz' - dt' (2)* Here, again, ds is a measured quantity (partly by scales and partly by clocks), and the right-hand side refers to the inferred locations. The units are chosen so that the velocity of light is unity. According to the old theory of relativity the measured "distance," ds, between two events is not affected by any uniform motion of the observer. If four new co-ordinates x^, a;^, x.^, x^, which are arbitrary functions of X, y, z and f , are introduced and substituted in the right-hand side of (2), we obtain an equation of the general form — ds' - ^11 dx-^- + goo dx.2- + . . . + ^g^., dx^ dx., + 2^13 dx^ dx.^ + . . . (3) where the ^'s are functions of the co-ordinates. Cubes and higher powers of the infinitesimals can be neglected. In natural rectangular co-ordinates the path of a particle under no forces is a straight line described with uniform velocity, or more briefly a straight line in four dimensions. This may be expressed in a form which is independent of the choice of co-ordinates, viz. fds is a minimum. By substituting under the integral the value of ds from (3) and applying the calculus of variations, we obtain the general equations of motion under no forces applicable to any system of co-ordinates. The ^'s and their derivatives will occur in these equations. In particular, by taking x^, x^, x.^, x^ to be rectangular axes rotating with the earth, we should obtain the equations' of motion of a particle under no "real" forces referred to those axes— in other words, the equations of motion of a particle in a field of centrifugal force. The centrifugal force enters into the equations through the intermediary of the corresponding ^'s ; and we thus get the notion of a field of force as defined by a set of values of the ^'s. Our hypothesis of the complete equivalence of gravitation to forces like the centrifugal force arising from a transformation of the axes of reference shows that we may also define the gravitational field by a set of values of the ^'s. In the case of the centrifugal force the values of the ^'s are such that by a trans- formation of the co-ordinates we can transform (3) to (2). It does not necessarily follow that this can be done when the ^'s have values corresponding to a gravitational field ; and in fact we cannot do it for a finite region of space, although, of course, in an infinitesimal element gravitation may be made to disappear by an appropriate transformation. The ^"s defining the gravitational field may be regarded as the ten components of a generalized gravitational potential. In fact, in rect- angular co-ordinates one of them, g_^^, corresponds to twice the New- tonian potential. t Newton's law is therefore expressed by Laplace's equation — VV44 = 0 (4) in free space. It is impossible to accept this as a general law satisfied by the g's, because, for example, it is not satisfied when the ^'s repre- * This formula is usually given with the reversed sign. t It is an easy iUustration to work out the transformation of (2) to rotating axes, when it will be found that g^^ is twice the potential of the corresponding centrifugal force. Vol. XXII. (No. 112) r 230 Professor A. S. Eddington [Feb. 1, Bent a centrifugal force. Clearly the hypothesis of equivalence requires that there should be one or more general differential equations satisfied by the ^'s in all cases, and not a special law satisfied by gravitational ^'s and another satisfied by distortion ^'s. If, then, the law is a general relation between the g's, it must hold for all systems of co-ordinates ; that is, it must be co-variant for all transformations. The general condition satisfied by the ^'s in the alseiice of a gravita- tional field is written in the form — B^" = 0 (5) IXCTT where the quantity on the left is known as the Kiemann-Christoffel tensor. (The word tensor expresses the property, that if it vanishes in one system of co-ordinates it vanishes in all systems.) It is a function of the ^'s and their first and second derivatives with respect to x^, x.^, x., x^. It has 256 components, formed by ringing the changes on the suffixes p, fx, 0-, r, giving them the values 1, 2, 3, 4.* By s^nnmetry many of these are identical, and we actually get (I think) 96 apparently different equations, some of which may not be independent. The equation (5) is to be understood to mean that all the 96 components vanish. The equation expresses the fact that a mathematical transformation exists which can transform (3) to (2) throughout space ; and that is the method by which it is obtained analytically. The general equation between the ^'s, allowing for a gravitational field, must be less stringent ; it must be such that it is satisfied when (5) is satisfied, but not necessarily vice versa. (Zero gravitation is a particular case of gravitation, but not vice versa.) The simplest symmetrical law that we could propose is — Bao- = 2 B^" =0 (6) p.l /^^^ This is clearly satisfied when (5) is satisfied. B/xo- is called the reduced (verjiinf/t) Eiemann-Christoffel tensor, and has ten different (but not all independent) components. It seems to be the only possible way of symmetrically building up another tensor out of the components of B^ ; and it appears also that equation (6) is the only CO- variant equation of the second rank (i.e., having ten components) that can be formed from the ^'s, and their first and second derivatives and linear in the last. Co-variant equations of higher rank (with more components) would impose too great restrictions, and like the Riemann- Christoffel tensor would not admit a gravitational field. For this reason (6) is chosen as the new law of gravitation. It reduces to the Newtonian law as first approximation. It remains to see how the equation (6) is modified when the space is occupied by mass, i.e. electromagnetic energy. What is to be * It would be cumbrous to write down the value of B^ ; but it will be fXffT understood that it contains g , x , etc., and the different components are got by giving the values 1, 2, 3, 4 to the suffiiLes. 1918] on Gravitation and the Principle of Relativity -^31 the new form of Poisson's equation V'f/) = - 47r/j '? It is found that equation (6) can be transformed into a Hamiltonian form — 6(/Hr?r) = 0 (7) where dr is a four-dimensional element of volume, and H a certain function of the ^'s and their derivates. The electromagnetic equations of Maxwell in the absence of a gravi- tational field can also be expressed in a Hamiltonian form — S(/H'^r) = 0 (8) where H' is a function of the quantities defining the electromagnetic field. ' It is clear that we must form the general equations, when gravitation and electromagnetic forces are both present, by combining (7) and (8) thus— 5(/(H + AH') dr) = 0 (9) The constant X, whose value cannot be predicted a Xfyiori, indicates the relation between the gravitational and electromagnetic effects caused by the same mass, and corresponds to the constant of gravitation. The mathematical operations, omitted in this brief sketch, are long and rather difficult ; but it is hoped that it maj" enable the reader to gather the general nature of the argument. R 2 •232 General Monthly Meeting [Feb. 4, GENERAL MONTHLY MEETING, Monday, February 4, 1918. Sir James Orichton-Brownb, Treasurer, in the Chair. J. Turner MacGregor-Morris, Professor Paule Popoirc, were elected Members. The Managers reported : That Dr. Mond, under the Conveyance and Deed of Trust of the Davy Faraday Research Laboratory of the Roval Institution, covenanted to pay to the Royal Institution before the" year 1926, the sum of £62,000 as Endowment Fund. The Trustees have in the most generous way anticipated the obligation by eight years, and have transferred the sum of £66,500 in 5 % War Stock to the Trustees (nominated by the Managers) of the Davy Faraday Research Laboratory Endowment Fund. This will add materially to the Income available for the purpose of promoting and maintaining the efficiency of the Davy Faraday Research Laboi'atory, in the Advancement of Original Research in Chemical and Physical Science. The Secretary announced the decease of Sir John "Wolfe Barry, on January 22, 1918. Resolved, That the Managers of the Royal Institution desire to record their sense of the loss sustained by the Institution and the World of Science by the decease of Sir John Wolfe Barry, K.C.B., LL.D., F.R.S., Past President of the Institution of Civil Engineers, M.I.Mech.E., M.I.E.E. Sir John Wolfe Barry was a Member of the Royal Institution for thirty- two years, and discharged the official duties of a ^Manager. He took an active interest in the welfare of the Institution, and as a ^Manager rendered invaluable service to the Institution. He was celebrated for many notable achievements in Engineering, and served on a number of Royal Commissions. He was also Joint Author of " Railways and Locomotives," in addition to other books. Resolved, That the Managers desire to express, on behalf of the ]Members of the Royal Institution, their most sincere sympathy with Lady Barry and the Family in their bereavement. 11)18] General Monthly Meeting 288 The Presexts received since the last Meeting were laid on the table, and the thanks of the Members returned for the same, viz. : — The Secretary of State for India — Proceedings of Indian Association for the Cultivation of Science, Vol. III. Part 4. 8vo. 1917. Archaeological Survey of India, Vol. II. 4to. 1917. Pusa : Agricultural Research Institute, Bulletin, No. 72 ; Scientific Reports, 1916-17. 8vo. 1917. Accademia del Lincei, Beale, Boma—Atti, Serie Quinta : Rendiconti. Classe di Scienze Fisiche, Mathematiche e Naturali, Vol. XXVI. 2° Semestre, Fasc. 7-8, Classe di Scienze Morali, Fasc. 9-10. 8vo. 1917. Accountants, Association o/— Journal for Oct.-Dec. 1917. 8vo. American Chemical Society — Journal for Nov. -Dec. 1917. 8vo. Journal of Industrial and Engineering Chemistry for Dec. 1917-Jan. 1918. 8vo. American Geographical Society — Geographical Review for Dec. 1917-Jan. 1918. 8vo. American Journal of Philology— No\. XXXVIII. No. 4. 8vo. 1917. Atkinson, Miss A. B., M.B.I. — Madame Curie. By M. Cunningham. 8vo. 1917. Priory of Inchmahome. 4to. 1815. Bankers, Institute o/— Journal, Vol. XXXIX. Part 1. 8vo. 1918. Birmingham and Midland Institute — Report for 1917. 8vo. 1918. British Architects, Boyal Institute of — Journal, Third Series, Vol. XXXV. No. 3. 4to. 1918. British Astronomical Association — Journal, Vol. XXVIII. No. 2. 8vo. 1918. Memoirs, Vol. XXI. Part 2. 8vo. 1918. Buenos Ayres— Bulletin of Municipal Statistics for July-Oct. 1917. 4to. Canada, Department of Mines — Mines Branch : Bulletin, Nos. 16-19. 8vo. 1917. Carnegie Institution — Contributions from Mount Wilson Solar Observatory, Nos. 128-133. 8vo. 1917. Communications to National Academy of Science, Nos. 46-49. 8vo. 1917. Chemical Industry, Society o/'— Journal, Vol. XXXVI. Nos. 22-24, 1917; Vol. XXXVII. No. 1, 1918. 8vo. Chemical Society— ^ouvubI for Dec. 1917. Chemistry, Institute o/— Proceedings, Part 4, 1917. 8vo. Civil Engineers, Institution of — Proceedings, Vol. CCIII. 8vo. 1917. de Villamil, Colonel, M.B.I, (the ^?<rations of the other, i.e. it will execute forced vibrations. These will not appreciably diminish the vibrations of the main circuit. 1918] on Vibrations: JVIechanicai, Musical, and Electrical 247 But let two electrical vibration circuits of comparable inductances and periods be placed together and started, then there is not only the action of the driver but also a distinct reaction of the driven on the driver. Hence, as the vibrations of one circuit start those of the other, the latter by their growth check the forruer, causing them to die away. Thus there may be an interchange of energy between them. This, as we have seen with pendulums, corresponds to the superposition of vibrations of slightly differing periods, pro- vided the action and reaction are small and the interchange slow. Further, it is known that if two such circuits are closely coupled those two periods differ more widely. Hence a third circuit (say a cymometer) responding to either of them may detect these separate periods by giving a resonance curve with two humps instead of one. IV.— Traces fro:^ Coupled Pexdulums. It has been seen that there is a certain general analogy between mechanical and electrical vibrations, whether free, forced or coupled. The question now arises as to whether this analogy may reach or approach a quantitative exactness in all or any respect, and whether it can be utilised in any way. Various mechanical vibrating systems differ widely. Some re- semble the electrical case very closely, but none appears to be completely and exactly analogous to them in every detail. Indeed the electrical case seems to be slightly simpler than any mechanical analogy yet put forward. But the differences are small, and the mechanical analogy may be highly useful as affording visible and tangible illustrations of those subtle electrical vibrations which can be neither seen nor handled. Especially is this the case if the model is readily adjustable to represent the various relations of the con- stants concerned and can be used for any initial conditions. Thus from such analogies some benefit may accrue to the non-mathematical student. But perhaps the highest advantage is realised only by those who combine the mathematical with the experimental study and grope after the ideal model which shall represent exactly the electrical or other phenomena in question. But whatever the uses of such models, certain it is that their design and study have exercised a fascination on many eminent scientists. In this con- nection, it may suffice to mention Faraday, Maxwell, Lord Kelvin, Lord Rayleigh, Sir Oliver Lodge, Sir Joseph Thomson, Professors J. A. Fleming, T. R. Lyle, and ^X. S. Franklin. ^ For either quantitative work or mere illustration the usefulness of such a model is much enhanced if its vibrations leave traces. This is easily arranged by letting the bobs carry funnels of sand under which a blackboard moves imif ormly at right angles to the direction of vibration. In the portable apparatus shown in Fig. 1 the S 2 248 Professor Edwin H. Barton [March 8, pendulums are of the double-cord type and allow both traces to be obtained simultaneously, and thus record the relations of amplitude and phase for each pendulum. AVith this apparatns the coupling can be varied at will and easily adjusted to any desired value from 1 per cent, to 60 or more. The greater the droop of the bridles the greater the coupling, the quantitative relation being simple. It is noteworthy that, for equal bobs and pendulum lengths, a 60 per cent, coupling gives superposed periods as 2:1, just as in the electrical case for equal periods. Indeed, with any specified coupling, the n .•M Fig. 1.— Coupled Pendulums. ratio of periods is the same for this mechanical case and for the electrical one. The masses of the bobs and the lengths of the pendulums are adjusted at pleasure, and the initial conditions may be anything that is desired. (Sinmltancous traces with this apparatus were then obtained, others exhibited, and photographs of a number thrown on the screen.) With equal bobs and equal lengths, the coupling being small, each pendulum exhibits in turn the same maximum and the same minimum as the other. With small couplings, equal lengths, but bobs as 20 : 1, the case of forced viljrations is approached. That is iyi8] Vibrations: Mechanical, Musical, and Electrical 251 to say, the heavy bob loses but little amplitude, while that of the light bob grows from zero to its maximum. With bobs as 5:1, the heavy bob loses appreciably, while the light one proceeds to its maximum. As the coupling increases from zero the ratio of the periods of the superposed vibrations of the coupled pendulums usually in- creases continuously till it equals or exceeds 2:1. AVhen, however, both lengths and masses are unequal, the short length having the heavy bob, a new feature appears. As the coupling gradually increases from zero, the ratio of the periods at first diminishes, reaches a minimum, and then increases. Thus the number of vibrations in a beat cycle at first increases, reaches a maximum, and then decreases. These special effects are shown in Fig. 2. They were theoretically predicted and then experimentally confirmed. The maximum number of vibrations in the beat cycle occurs for the highest coupling shown in the figure, viz. 6*8 per cent. The details as to bobs, lengths and couplings are all indicated on the figure. The able collaboration of Miss H. ^I. Browning in this work was gratefully acknowledged. V. — Brass Instruments and the Low " F." Leaving the pendulums which have only two vibrations at a time, the case of brass instruments with a number of simultaneous vibra- tions was next considered. It is well known that the vibrations from most musical instruments are what is called compound. They consist of a series of tones of commensurate frequencies sounded together. Thus, if the pitch of the note is said to be 100 per second, there is not only a prime tone of this frequency, but also a second tone of 200 per second, a third of 3o0 per second, and so forth. This law applies to strings, to open parallel pipes, and to a complete cone with its base open. It also applies as a close approximation to the brass instruments in general use. This approximation is trace- able to the departure from the strictly conical form as regards the mouthpiece, the bell, and the special shape of the intermediate portion. In these brass instruments the possibility of this compound tone, or multiple resonance, is utilised for the production of distinct notes. Thus, out of the tones possible to the instrument the player may elicit the set 200, 400, 600, 800, etc.; or the set 300, 600, 900, 1200, etc. These would be said to have the pitches of their primes,- or lowest components 200 or 300 respectively. Or, to put it musi- cally, they would be the octave or the twelfth of the fundamental (or pedal) possible on the instrument. The pedal of the instrument is not usually employed for musical purposes, but can be sounded if specially wished. Now, there is a tradition among players of brass 252 Professor Edwin H. Barton [Marcb 8, instruments that a note called by tbem a low " F " can Ije sometimes obtained. This note would have on the foregoing scheme the fre- quency lS'd}i. At first the possibility of this '• F " seems scarcely crediljle to the theoretician. But after hearing and producing the note, the necessity of accounting for its possibility was forced home. And really the explanation proves very simple. It usually depends upon two points ; (a) the spread or diffused resonance of of the pedal ; and {h) its intentional mistuning with respect to the other notes of the instrument. These are taken in order. («) For theory shows that, other things being equal, the lower the note of such an instrumei>t, the easier it is to force its vibrations out of tune, sharper or flatter. Thus, with the pedal the range of Table II. — Spread Resonance of Lower Open Notes on Brass Instruments. resonance is such that the note may be sounded nt any pitch what- ever over a range of five or six semitones. (Jb) Since the law of frequencies 1(>(>, 2, etc., is only approximately true for these instruments, in order to secure good relative tuning of the higher notes which are in constant use the pedal (which is not used musically) is purposely mistuned. On some instruments it may be say, D or E flat, instead of C. Hence, if the central pitch of the pedal is sharpened two or three semitones, and it is possible to force this note both up and dow^n two or three semitones, it becomes possible to sound the pedal of true pitch C, to sound the low " F," and to sound notes of every 1918] on Vibrations: Mechanical, iVIusical, and Electrical 258 pitch between. (This was demonstrated on a euphonion kindly lent by Messrs. Boosey & Co.) The low " F " is also possible on the bombardon. Both these instruments are characterised by large conical tubing, and the low " F " is obtained by the spread resonance of the sharpened pedal. In the case of the trumpet, cornet and French horn with much narrow tubing, the pedals are flattened, so that a pedal of true pitch can only be obtained by the spread resonance, and the " F "' is impossible. On the trombone, which has much small parallel tubing, the low " F " may be obtained occasionally by the downward spread resonance of the second partial (or note number iwo), which is an octave above the pedal. (Demonstration.) The pitch of the notes which have been obtained on six types of instruments by four ex- perimenters are shown in Table J I. YI. — MoNOCHORD Vibrations. Consideration was next given to the vibrations of stringed instru- ments, beginning with the monochord, because of its striking sim- plicity. From the work of mathematicians (with a little help from ex|)eriment) the various possible vibrations of strings, whether plucked, struck or bowed, have long been well known. But a little reflection will show that many other problems are still left con- fronting the physicist. For identical strings excited in the same way, but mounted on different instruments, will produce very diiterent effects on the ear. In other words, the worth of a violin does not lie in its strings, but in its sound-box. This leads to the inquiry as to what happens to modify the vibrations as, passing from the strings, they reach in turn the bridge, the belly (or sound-board) and the adjacent air. It is easy to see that this problem is somewhat complicated, since it presents so large a number of variables. Thus, there lie at the experimenter's disposal the pitch of the string, its material and dimensions, fhe place and manner of excitation, the material and disposition of the associated parts of the instrument, the place of observing the belly, the portion of the bridge observed and the directions of its motions, and, lastly, the spot at which the motion of the air is observed. In this way a scheme for over a thousand observations could be sketched, even for an instrument with but one string. Hence no exhaustive treatment of the problem can be quickly obtained. But a beginning has been made, and by very simple means. In a series of experiments simultaneous records have been photo- graphically obtained of the vibrations of the string and of some other part of the instrument. The monochord was placed on a table and light from a vertical slit was focused upon the string near 254 Professor Edwin H. Barton [March 8, its centre. The real image of this sht, crossed by the shadow of the string, was then focused by a second lens on to a photographic plate in a dark room. This plate was shot along horizontal rails by elastic cords which were just slack when the plate received the light. Thus the plate moved uniformly and horizontally, while the shadow of the vibrating string showed its special motion vertically. The corre- sponding motions of bridge, belly, or air were obtained on the same photographic plate by the light reflected from a tiny rocking mirror , A 1 /• / 1 f. t / i ' .^X' i 1 ^'V 1 i i -e i 1 / ■ .. ^ '|oc -..j ' i 1 t: . _, ... y^ w \ - -. ■ Fig. 3. — Monochokd Apparatus. whose slight tilt was produced by the motion of the part under test. (The principle of this experimental method was then demonstrated, the humped form of the curve due to phicking the string and the two-step zig-zag produced by careful bowing being shown.) Fig. 8 g'ves a diagram of the method for the monochord, also a detail of the rocking mirror for the bridge's motion. Fig. 4 shows photo- graphic traces for the monochord string and belly. The two curves 1918] Vibrations: IVIechanical, Musical, and Electrical 259 alike were taken separately to test if the apparatus worked satis- factorily. The other two curves, slightly different from each other, show the distinction in appearance between the records of a bad tone and a good one. In this work the assistance of Messrs. C. A. B. Garrett and J. Penzer was acknowledged. In 1014 Prof. C. Y, Ptaraan, of Calcutta, by experiments somewhat similar to the above, showed that the forward speed of a string where it is Ijowed is identical with that of the bow itself. YII. — Violin Yibratioxs. If the problems of the monochord were numerous and complicated, those of the violin are still more so. For there are now four strings instead of one ; further, all are different in thickness and pitch, and are capable of use in sections of varying length. Again, the sound- box is curved in a variety of ways. Finally, the reinforcement of the belly is asymmetrical. The bass bar lies almost under the fourth string, while the sound-post stands near that foot of the bridge which is under the first string. In the work on the violin assistance was received from Messrs. T. J. Richmond, T. F. Ebble- white, and W. B. Kilby. A number of vibration curves obtained for the violin were shown on the screen. Fig. 5 gives one set of these, showing the vibrations of each string as indicated by the letters G, D, A and E. The D string was plucked by a sharp point, the other strings were bowed. The white line shows the longitudinal motions of that corner of the bridge near which the first, or E, string YIIL— Co^'CLUSIOx. With respect to the sympathetic vibrations occurring in stringed instruments, it is obvious that though a little has been done much more remains awaiting attack. Thus, the violoncello, guitar and harp might be dealt with. But specially, because of its immense vogue, the pianoforte needs thorough investigation. A start Avas made some time ago by Mr. G. H. Berry, and further researches are now in progress in London under the joint direction of scientists and piano manufacturers. In the past music lovers and scientists alike have been deeply indebted to the makers of musical instruments, who have themselves received but little help from science in return. The lecturer ex- pressed the hope that science might shortly pay off part of its debt to the musical craftsmen of the country and help to make the British piano second to none in the world. [E. H. B.] 260 Right Rev. W. Boyd Carpenter [March 15, WEEKLY EVENING MEETING, Friday, March 15, 1918. J. H. Balfour Browne, K.C. LL.D., Vice President, in the Chair. Right Rev. W. Boyd Carpenter, K.C.V.O. D.D. The Romantic Revival. It is always interesting to note the waves of fashion as they rise and fall amid "^ the tides of the world's progress. I am to speak to you al)out the Romantic Revival of English Literature. Its story may l»e taken as measuring an incoming tide, but the surface of the movement is broken by the personal animosities and prejudices : these are as the noisy waves, which by calling our attention to themselves make us forget or ignore the power of the tide. I cannot hope to discriminate fully and fairly between the majestic rush of the waves and the silent power which works unseen beneath them : but the evidence of the power of the Romantic movement will, I hope, be apparent to us as we proceed. Perhaps two anecdotes here will serve to illustrate both the force of the movement and the prejudices against which it had to contend. The first of these illustrates the ascendancy of the movement over the active minds of the 19th Century. The late Professor Courthope has given us his opinion that from one point of view Byron is " the most complete rejiresentative of the romantic movement in English poetry" (Hist, of English Poetry, vol. vi. p. 274). Here is an example of its power. One day the late Lord Beaconsfield said to Lord Rowton, " Monty, it takes a'hundred years to breed a poet ; and Byron is the poet of the 19th Century." Mr. DisraeU was born in 1805. He was in his boyhood when the First Canto of "Childe Harold" had made Byron famous, and his young days were brought under tlie si>ell of 'the extraordinary popularity of "The Bride of Abydos," " The Corsair," and the later cantos of " Childe Harold," and of the fascination which the restless and enigmatic character of the poet exercised over those whose hearts responded to the call of liberty. Though other poets greater than Byron arose. Lord Beaconsfield never outgrew the prepossessions and memories of his youth. The second anecdote shows the strength of the prejudice against which the Romantic movement had to contend. Though there were enthusiasts who welcomed the younger poets, reverence for 1918] on The Romantic Revival 261 earlier bards did not disappear. Deli.crht in the Classic age never wholly died. The French painter De la Koche prided himself on his Classical severity. He was at work one day upon a picture, when the amiable and accomplished secretary of a French society came and watched him at his work, and after a silence of observation, exclaimed, thinking to compliment hiir, "You are the very Victor Hugo of painters." The painter flung down his brush in disgust. He had no wish to be compared with a leader of the Romantic school. There were many in the world of letters who felt like the French painter The love of the Classical age did not die in England any more than it did in Prance ; but the new school, in whose atmosphere the old among us spent our younger days, reached a pre-eminence and popularity which changed the current of thought and of what is perhaps more powerful — of taste. Let me imagine that a student has strayed into a library. Let me suppose that he has no knowledge of the rival claims of Classical and Romantic writers. He turns to the long rows of bound volumes of the Reviews. He takes down a volume of the Quarterly or the Edin- hurgh and reads a criticism on the writings, we will say, of Scott or Wordsworth. He learns that in the judgment of the reviewer "Wordsworth has little claim to the respect of the public or the title of a poet. I give you one or two specimens of what he might read— indeed, of what you may all read if you were minded to spend an hour or two among old Reviews. Of Scott we read that he has ''a tone of animation, unchecked by any great delicacy of taste or elegance of fancy." The reviewer regrets that a writer of such talents should " consume them in imitation of obsolete extravagance. To write a modern romance of chivalry is like building a modern abbey or an English pagoda. There is little connected incident and a great deal too much of gratuitous description" {Ed. Rev.. 180'S). Of AVordsworth the same Review fourteen years later says : " The Lake school of poetry we think is now pretty well extinct. Words- worth has fallen into a way of writing prosy, solemn, obscure, feeble kind of mouthing, sadly garnished with shreds of phrases from Milton and the Bible, but without nature and without passion, and with a plentiful lack of meaning, compensated only by a large allowance of egotism " {Ed. Rev., 1822). Our reader is tempted to think that it will be but wasted time to spend thought or study upon a writer who is thus described. But the articles are piquant, and he would like to hear a little more. He takes down another volume of the same Review, and now he reads criticisms of a wholly different strain. A man called Wordsworth is now declared to be a poet of no mean order. His principle of pure diction has caused the ex- purgation of absurd terms. The nightingale is no longer Philomel or the tuneful bird of night. Our reader rubs his eyes. Can this be the same poet ? If so, how has cursing turned to blessing ? Is Balaam also among the Vol. XXII. (No. 112) t 262 Right Rev. W. Boyd Carpenter [March 15, critics ? And what interesting creature has led him to change his mind ? Our reader examines more carefully. The poet is the same. The dates of the Reviews are now examined. The dates of the abusive article are in the early part of the century ; the kindly and laudatory articles are less than a generation later. The reader is more perplexed than before. Is there any fixed canon of poetry ? he asks. AVas that good poetry in 1834 that was vile stuff in 1824 ? If opinion can jump about in this style, how can any simple student know how to direct his steps ? Poetry has been an art for thousands of years. Do we know so little about it that we cannot apply any fixed standard to estimate its value ? Is there no golden rod by which we may measure it ? Here we open up a question too great to answer ; my time this afternoon, my capacity at any time, is, I think, not equal to the task. Nevertheless, lest you should think me cowardly, let me say one word on theoretical conceptions of poetry. I have found them one and all to be wanting. Tliey may be summarized in this way. Some give us a vague definition which includes too much ; some, on the other hand, attempt the would-be exact definition which usually excludes some essential quality ; and, lastly, there is the descriptive attempt, which of course does not define at all. When Milton tells us that poetry should be simple, sensuous and passionate, he speaks of qualities which we can probably admit are qualities indispensable to good poetry ; but he does not define poetry any more than you define a man by telling us that he must have form, reason and volition. When Mr. Swinburne tells us that poetry should possess imagina- tion and harmony, we quite assent, but we feel that we are no nearer a definition of poetry. As one who has expressed a dissatisfaction with attempted definitions, perhaps I may be allowed to go further and express, with much hesitation and deference, the doubt whether any true and real definition of poety can be given. Let us put this in another way. Can we ever define that which is in its nature beyond science ? Within the limits of science we may and we must define ; but there are regions in which science is a stranger. Science walks on two feet ; but imagination has wings, and science, with rule and compass, cannot follow her in her flight. We know that poetry, like imagina- tion, has eyes which can pierce beneath the surface of things, and wings that can lift her heavenward. But when we try to hold her fast that we may make an inventory of her dimensions she escapes from lis. That which has its home in heaven must ever elude the grasp of earth. But if some demur to this view, perhaps they will l)e more in agreement with me when I say that the definitions we quoted were given by poets, and if anyone can give a definition of poetry, least of all can the poet do so. The man of science may tell us how a 1918] on The Romantic Revival 263 thing is done ; the artist seldom can. He may give us some information about certain of the minor or more mechanical parts of the processes in work ; but the true secret of his art is hidden most of all from the artist. Once I visited Mr. Tinworth in his studio. I asked him something about his process of work. He took up a piece of clay, and under his nervous and pliant fingers, which seemed to have life and reason in their very tips, the tiny piece of clay took human shape. " That is how I do it," he said, as he crushed it into shapelessness again. Yes, that is how we do it, the poet as well as the artist tells you ; but the how is as much a mystery as ever. The artistic and the poetic mind is bad at definitions, and therefore when Matthew Arnold said that poetry was at root a criticism of life, we take the liberty of believing that he is projecting the shadow of something which profoundly interested him over his idea of poetry and mistook the outline of the shadow for a definition of poetry. Indeed I would go further — and this has intimate bearing on the rise of the Romantic School of poetry — and express my belief that a poet never writes so badly as when he is under the conscious rule of some theory of his art. He is only master when he rises so far above it (I do not say neglects it) as to be unconscious of its existence ; for there is always "in true poetry a certain happy abandon which tends to create that the quality of " inevitableness " of which "Words- worth spoke. Briefly, then, I distrust definitions, but this is quite a different thing from saying that there are no qualities which should be found in poetry. AVe look for imagination and harmony ; we delight in simplicity where we find it ; we ask for colour, and we love it as it appeals to our sense of fitness. But we must give poetry a latitude which is claimed rightly by all imaginative arts ; and we must allow to the poet the freedom of his individuality. He must, as has been said, create his own public. He must be true to himself if he is to be true to those souls of whose secret thoughts and unspoken aspirations he is to be the voice. When, therefore, oar reader in the library asks whether that is good poetry in 183ox and the pig-tail disappear. The 19th Century and sans-cuUotism are at the door. We make our bow to the new-comer, and we try to become acquainted with his features. He embodies the spirit of Revolt. What is the revolt which he expresses ? New influences are at work. Three great factors have Ijeen at work in Society ; and all of them are handmaids of change — the revolution, machinery, and missionaiy enterprise. They are all movements of and for the people. The Revolution will proclaim the Rights of ]\Ian ; machinery will popu- larise the products of the world ; missionary enterprise will make its protest on behalf of forgotten and despised races. To those who have eyes to see it, these movements mean that the treasures of life will no longer be the monopoly of the few. The singer will no longer sing to please his patron. He has heard the murmur of those voices which are as the waves of the sea. He thinks no longer of some Lord Chesterfield, or of Dr. Johnson. He may wince under the lash of Jefi'reys ; Imt he will appeal from the judgment of the Edinburyh to that of the public, and the public is no longer the few who are cultivated ; the public is to him the masses, whose lives are sad and whose hearts he longs to reach. He is moved by a higher conception of his calling ; he feels that the 1918] on The Romantic Revival 267 singer should be a seer ; tlie people need a guide and a voice. May not his art be a voice and guide to them ? Does he live only to sing a new song in the people's ears ? He may have but a small provision, but if the people are hungering, he will spread forth his scant fare in the wilderness. It will be something if he can appease their hunger. It will be reward enough if he can give a new song to the new generation. •' And here the singer, for his art Not all iu vain may plead, The song that stirs a nation's heart Is in itself a deed." I do not mean that thoughts such as these rose consciously in the minds of the singers of the new poetry ; but I do mean that the movements of the age made the idea of the people clearer, and more living and more operative to those whose minds were open to the meaning of the lightning and thunderings and voices which accom- panied the close of the 18th Century. The literary movement was a popular movement. It was also a revolt against conventionality. It was a plea for liberty. Any custom may after a time become a tyranny ; and this not because it is bad, but because, as Tennyson reminds us, even a good custom may corrupt the world. The cry for change may be a puerile or a manly cry. It may be the cry of one who is heedless and inattentive, and who is as a child wanting a new plaything because it has not the energy or inteUigence to get amusement or interest out of the old. On the other hand, it may be the cry of the builder who is asking straw to make his bricks. Life shows itself to be life by its resolute selection of the form in which it can best express itself. Life governs form far more than form governs life. Wherever there is true life there will be a certain majestic independence and deter- mination to live its own life. And here an 18th Century worthy will support me. " Xo man," said Dr. Johnson, " ever was great by imitation." The fault of the old generation had not been, as some have said, that they were hopelessly prosaic. I cannot agree that there is any titness in calling Dryden or Pope "prose writers." You may assign them any rank you please, high or low, in the Pantheon, but you cannot turn them out of doors and place them in company with Miss Burney and Miss Edge worth. If Pope is not a poet, who is ? is a fair question, if we understand it rightly. Pope does not attain to the rank of those who sit in the snow-crowned heights undisturbed by the storm of criticism which rages round the lesser heights ; but if we are to count every poet a prose writer who is prosy we shall have few poets left. There are traces of prosaic wilderness enough in Wordsworth as well as Pope, but as we cross them we can hear the murmur of the burn, and we know that we shall before longf 268 Right Rev. W. Boyd Carpenter [March 15, descend into a green glade, softened in sweet shadow and musical with running water. The fault of the century lay rather in the fastidiousness of taste which became too burdensome for Nature. The age was too deter- minately genteel. The writers were afraid to laugh — they only simpered ; they gently pressed the delicate cambric across their eyes, because it was not good taste to show emotion. " Fear of being vulgar, fear of being singular, these were the real nightmares that sat upon 18th Century poetry." Against this conventionality the new school revolted. It claimed the right to be natural. It entered once more into closer connexion with the world of Nature. It no longer treated Nature as a beautiful thing, but a thing outside— a treasury of images and tropes. It sought to get into the heart of Nature. It loved simplicity. As was to be expected, it overdid it. In striving for simplicity it some- times assumed a simplicity like that of the dear little country-girl on the stage, who is artfully simple, who is self-consciously straining after naturalness of manner, and whose affectations are contradicted by the elaborate daintiness of her sham rural costume. Are Wordworth's little girls and peasants always truly natural ? Do they not sometimes look up to us with a certain theatrical pert- ness ? The very effort to avoid the conventional betrays people into another kind of conventionality. And here I may make a remark which you will laugh at as quite absurd. The only way of writing naturally is to be natural while you write. The poet who has his theories too fixedly in his mind as he writes will miss that happy naturalness w^hich only comes to those who do not look for it. But nevertheless the determination to be natural and simple was good. There were things which needed to be done, and the w^orld was going to do them. There were things which needed to be said, and men rose up to say them. We shall no longer hear Pope or Addison or Goldsmith. Instead we sliall hear Collins and Gray, Byron and Shelley. The heroic couplet will give place to a freer fashion of verse. The ponderous novels of Fielding and Richardson will be superseded h\ the ardent romances of Sir Walter Scott. And even the most devoted admirer of the Classic age will admit that English literature has gained hy the movement. I am not here to discuss Wordsworth's theories of poetry. I have said — what I believe — that a poet's theories of poetry are probably w^orse than a critic's, and that Wordsworth did his best work when he left his theories alone and wrote in happy abandon- ment and forgetfulness of his self-made rules. But whatever be the value, or want of value, of these theories, the movement which is called Romantic was the dawn of a period of song which was sweeter, full-throated, more varied, more widely appealing than any which had ))een heard for a hundred years. I decline to enter into the question whether Pope was a greater 1918] on The Romantic Revival 269 poet than Wordsworth, or Diyden than Tennyson, or Shelley than Gray. These always seem to me to be vain and profitless com- parisons. When I go into a garden I do not argue that a rose is nobler than a lily, or a daffodil than a crocus. I bless each flower as it comes. Its beauty and its fragrance are its own. Each has its season, and in their season all are welcome. And in this fashion I can enjoy the rich banquet which the Romantic School has spread for us. The song'which Burns wrote on Xew Year's Day more than a hundred years ago expresses the popular side of the movement, and has graven it into the souls of every generation since : — " The rank is but the guinea's stamp, The man's the gowd for a' that." When " John Anderson my Joe " has been sung many a " frosty pow" has stolen unseen across the sofa and clasped a thin white hand upon which the worn wedding-ring hangs loosely. No generation, least of all our own, can afford to forget the lesson which Wordsworth taught when he sung : — " The world is too much with us ; late and soon, Getting and spending, we lay waste our powers ; Little we see in nature that is ours ; We have given away our hearts, a sordid boon 1 The sea that bears its bosom to the moon ; The winds that will be howling at all hours, And are up-gathered now like sleeping flowers ; For this, for everything, we are out of tune ; It moves us not. Great God ! I'd rather be A Pagan suckled in a creed outworn ; So might I, standing on this pleasant lea, Have glimpses that would make me less forlorn ; Have sight of Proteus rising from the sea ; Or hear old Triton blow his wreathed horn." But it is in no single passage that we can fairly measure the power of any writer. " Not," says Mr. Myers, " not the isolated expression of moral ideas, but their fusion into a whole in one personality is that wiiich connects them for ever with a single name. Therefore it is that Wordsworth is venerated ; because to so many men— indifferent, it may be, to literary or poetical effects as such — he has shown by the subtle intensity of his ow^n emotion how the contemplation of Nature can be made a revealing agency, like Love or Prayer, an opening — if indeed there l^e any opening — into the transcendent world." And when we remember Him who said " Consider the lihes," " Consider the ravens," we may well feel how much of larger thought and fuller life we lose who do not keep our minds open to the soothing benison of the messages which Nature is bringing to us from the Father of all. The gains of the movement can hardly well be reckoned up. It was a popular movement. This may mean what is good or what is 270 Right Rev. W. Boyd Carpenter [March 15, bad. In a good sense it was popular, for it recognize! more than did tbe poets of preceding ages the ministry which poetry might exercise" towards the people. It was a r ovement against conven- tionality and towards naturalness. This virtue it shared with almost every other new movement in art, letters and faith ; for is it not often the case that a new movement is the swing of the pendulum away from the art or religion which have tended to become con- ventional ? But though it shared this feature with many other movements, we must not on that account be less grateful to those who opened new avenues when men were seeking wider room in which their developing powers might exert themselves. It was an opportune movement, for it came at the time when science and the mechanical arts were about to lengthen their cords and strengthen their stakes. It was Avell that at such a time, when science might have monopolised the human mind and the increased opportunities of wealth might have engrossed men's thoughts, singers and writers should have arisen who conjured up before the popular imagination another world, ideal if you will, but not less real on that account, which might woo them from vulgar and too earthly thoughts. We cannot estimate how much the reading of the poetry and romances of Walter Scott has kept alive in the popular mind an interest in and a love of things better than those which perish in the using. Such gain the movement gave to English life. How much the national life was enriched we can perhaps estimate by asking our- selves whether we could afford to lose Shelley's " Skylark," " The Ancient Mariner," "The Ode to Immortality," "The Lay of the Last Minstrel," not to mention a host of other now familiar and cherished Avorks. The movement bequeathed us rich legacies. Rich as these were, we must leave them behind : for we are called to press onward and ever up the steep of the hill on whose summit the eternal sunlight shines. We in our generation have our work to accomplish, as these men had : but the songs which these men sang will cheer us as we struggle upwards. We shall share the feelings of Wordsworth when, on the side of the hill, he hccird the song of the solitary reaper rising from the vale below : — " Whate'er the theme, the maiden sang As if her song could have no ending ; I saw her singing at her work, And o'er the sickle bending ; I listened motionless and still , And as I momited up the hill, The music in my heart I bore, Long after it was heard no more." Thus it is that the songs of the past which have once struck into the hearts of men, not only find a resting-place there, ])ut bring their inspiration to the makers of other songs. 191^] on The Romantic Revival 271 But the critic bids us pause. He asks us whether we are sure of inspiration in the future, as in the past. We cannot prophesy : hut we may at least draw our hopes from the principles which are attested by the past. And if the question is asked whether tne poetry of the future is likely to be as good as that of the past, I think we may say that there is no reason why it should not. But, while we record our hope, it is only fair to say that there is no lack of gloomy-minded critics who shake their heads over all who dare to hope. In their judgment the world of letters is always on the decline. Such folk will probably remind us of the opinion of Macaulay. which was that as civilisation advances poetry will decline. Though some would not accept so depressing a statement of the question, they might argue that with advancing knowledge the realm of imagination is necessarily narrowed, and to that degree the kingdom of poetry diminished. Science encroaches on the domain of fancy ; and poesy, like a bird no longer free to stretch her wings, grows silent in her cage. The captive muse disdains to use her harp. But is this picture an adequate or true description of the matter ? Is it a fact that the advance of science narrows the domain of imagination ? The analogy of the argument is faulty. It presup- poses a limited territory shared between the two powers, science and song. If this is a correct picture, it follows of course that the larger the territory annexed by science the smaller is the area left to poetry. But the true picture is of another sort. Both scienee and poetry are as travellers exploring together the great infinite which surrounds them. Year by year science adds new territory to the domain of things known and so extends its circling border into the realm of the great unknown ; but the wider her borders grow, the longer is the frontier line which separates the known from the unknown, and the greater is the realm which imagination may claim as lier heritage. Or, to put it in another way, as knowdedge increases our sense of the infinite grows. In the days of men's ignorance their minds did not travel far. Imagination did not penetrate deeply into the gloomy wood which surrounded her dwelling. But as knowledge extends her borders the world is found to be greater : the infinite means far more to us than it did to our forefathers. AVe are as those who have climbed higher, and the prospect is wider and the field of mystery which spreads beyond is greater and more marvellous than ever. In short, as I contemplate and rejoice in the conquests of science, the picture which I see grows larger and nobler. I seem to see science unfolding the gates of knowledge and saying to the children of fancy, " I have swept the wide spaces where the stars are shining, and I have seen their colour and the fashion of their being ; I have weighed them in the balance, and I have marked their birth and their decay. I have pierced into the fabric of the universe and I have flung the elements of worlds upon my spectroscope. I have Ijroken 272 The Romantic Revival [March 15, down the prison walls of envious and imprisoning materialism. I have seen everywhere life and movement. I have heard everywhere the whirring of God's chariot wheels, and I have found that the impulse of His will vibrates through untravelled and eternal regions. You need fear no more ; go forth and sing freely of the living, energizing, inspiring, force divine which has worked and is working now and has worked in all the myriad worlds and interstellar areas since the first day when the stars first sang together and all the sons of God shouted for joy." ^Ye have not yet seen among us the poet who can digest the vast knowledge of to-day and sing once more the great eternal and uni- versal song for which human kind is ever waiting ; but we have numberless poets who have seen the travail of man, the glory of God, and the wonder of life, and who have sung to us right worthily of the pain of earth and the call of heaven, and of the faith which lives imperishable in the heart of man, whose song, among the ruins of broken hopes and shattered realms, is still the song of nobler hope. " In joy, in joy of the light to be, 0 Father of lights, unvarying and true. Let us build the Palace of Life anew ; Let us build for the years we shall not see." Yes, the song of the true poet always ends with the " Sursum Corda " of changeless trust. We put aside the pessimism, which whispers that the bright realms in w^hich poetry loves to ramble have passed into alien hands. It is not true that the territory of imagination shrinks as the frontiers of science are advanced. It is true that knowledge needs to be assimilated before imagination musing on new^ truth can take fire and break forth with unfettered voice. It is true that an age of eager acquisitiveness is not always an age of creativeness ; time is needed before food can be converted into strength. But nevertheless as man's knowledge grows, the sense of our ignorance will grow, and the tireless curiosity of our nature will yearn to explore the untrodden regions. AVith such stimulus men will find resources out of which the art of expression will be enriched. New stops will be added to the organ, and richer melodies will roll up to heaven. If God has new light to break forth for men. be assured of this that men's hearts and imaginations will respond to the broadening light. Science, which is the art of knowing, is bound to grow-; as it grows it will increase its wide spreading boughs, and offer welcome shelter to the winged ones whose haunts are between earth and sky. However great may be the tree of knowledge there will always be birds of heaven to sing among the branches. [W. B. C] 1918] General Monthly Meeting 273 GENERAL MONTHLY MEETING, Monday, April 8, 1918. Sir James Crichton-Browne, J.P. M.D. LL.D. D.Sc. F.R.S., Treasurer and Vice-President, in the Chair. Dr. H. W. Beedham, H. C. Jenkins, Miss E.. Noel, were elected Members of the Royal Listitution. The Right Hon. Lord Rayleigh, O.M. D.C.L. LL.D. F.R.S., was nominated for Election as Honorary Professor of Natural Philosophy at the next General Meeting on May 6, 1918. Professor Sir J. J. Thomson, O.M. LL.D. Pres.R.S., was nomi- nated for Election as Professor of Natural Philosophy at the next General Meeting on May 6, 1918. The Managers reported, That at their JMeeting held this day, they Resolved, in conformity with the Bye -Laws (Article 1), Chap. XL, to issue a Notice to all the Members that at the General Monthly Meeting to be held on LEay 6, 1918, a Resolution will be submitted that the Treasurer of the Royal Institution, Sir James Crichton-Browne, F.R.S., be authorised to execute and sign a Power of Attorney in a Form submitted by the Dutch Government, to enable the sum of 21,000 guilders (nominal value) inscribed on the Ledgers of the Public Debt of the Netherlands in Amsterdam, to be sold with a view of the proceeds being remitted to the Bankers of the Royal Institution, to be reinvested in Trustee Securities in accordance with Article 5, Chapter II. of the Bye-Laws. The Presents received since the last Meeting were laid on the table, and the thanks of the Members returned for the same, viz. : — The Secretary of State for India — Agricultural Research Institute, Pusa : Bulletin Nos. 70-74. 1917. Geological Survey of India, Memoirs, Vol. VI. Part 3. Accademia dei Lincei Reale, Royna — Atti, Serie Quinta : Rendiconti, Nos. 1-3 1918. 274 General Monthly Meeting [April 8, American Chemical Society— Journal for ]\Iarch 1918, Vol. XL. No. 3. 8vo. Joui-nal of Industrial and Engineering Chemistry for March 1918. 8vo. American Geographical S'ocu'f?/— Geographical Review, Feb. 1918. American Journal of Physiology — Vol. XVL. Nos. 1-3. March 1918. American Philosophical Society — Transactions, Vol. LVI. Nos. 3-6. American Physical Society — Review, Vol. XI. No. 2. Asiatic Society, Royal— Journal for Feb. 1918. 8vo. Astronomical Society, Boyal — Monthly Notices, Vol. LXXVIII. No. 3. Jan. 1918. 8vo, Australia, The High Commissioner for — Australian Advisory Council of Science and Industry, Bulletin No. 5. Bankers, Institute of — Journal, Feb. 1918. British Architects, Royal Institute of — Journal, Third Series, Vol. XXV. No. 5. March 1918. British Astronomical Association— Journal, Vol. XXVIII. No. 4. Svo. 1918. Cafia la, Department of Mines — Summary Report for 1917. Carnegie Instittite — Carnegie Scholarship Memoirs, Vol. VIII. Svo. 1917. Chemical Industry, Society o/— Journal, Vol. XXXVII. No. 5. March 1918. Chemical Society — Journal for Feb.-March 1918. 8vo. Commonwealth of Atistralia — Advisory Council of Science and Industry. Bulletin No. 4. Cow, Mrs. Douglas — Cinderella. By Marion Roalfe Cox. An Introduction to Folk Lore. By M. Roalfe Cox. Cinderella. By M. Roalfe Cox (Essay in Folk Lore, June 28, 1907). Editors — Aeronautical Journal for Feb. 1918. 8vo. Athenaeum for IMarch 1918. 4to. Chemical News for March 1918. 4to. Chemist and Druggist for March 1918. 8vo. Church Gazette for March 1918. 8vo. Concrete for March 1918. 8vo. Dyer and Calico Printer for March 1918. 4to. Electrical Industries for ^Nlarch 1918. 4to. Electrical Times for March 1918. 4to. Electricity for March 1918. 8vo. General Electric Review for March 1918. 8vo. Horological Journal for March 1918. Svo. Illuminating Engineer for Jan. 1918. Svo. Journal of the British Dental Association for March 1918. Svo. Junior Mechanics for March 1918. Svo. Law Journal for March 1918. Svo. London University Gazette for ]March 1918. 4to. Marine Magazme for March 1918. Model Engineer for March 1918. Svo. Nature for March 1918. 4to. New Church Magazine for ^Nlarch 1918. Svo. Notes and Queries for March 1918. Power-User for March 1918. Svo. Science Abstracts for Feb. 1918. Svo. Zoophilist for INIarch 1918. Svo. Electrical Engineers, Institution o/— Journal, March 1918. Svo. Franklin Institute— J ournal, Feb. 1918. Svo. Geographical Society, Royal— Journal, Vol. LI. No. 3, March 1918. Hadfield, Sir Robert — Statement of the German Union of Technical and Scientific Societies. Indian Association for the Cultivation of Sciences — Proceedings, Vol. III. Part 5, 1917. John Hopkins r?tifcrsi^?/— University Circulars, 1916, Nos. 1-10. 1917. No. 1. ^.^ University Studies, Series XXXV. No. 1 ; Series XXXIV. Nos. 2-4. Life-Boat Institution, Royal ISIational— Journal for Feb. 1918. Svo. 1918] General Monthly Meeting 275 London County Council — Gazette for ^larch 1913. -Ito. London Society — Journal for March 1918, No. 16. 8vo. Meteorological Office —Monthly Weather Reports for Feb. 191S. 4to. Weekly Weather Reports for March 1918. 4to. Geophysical Journal— Daily Values for Jan. 1917. Monaco, Musde OceanograjjhirpLe — Resultats des Campagnes Scientifiques accomplies par Albert I. Prince de Monaco. Bulletin, Nov.-Dec. 1917 ; Jan. -Feb. 1918. Montenegrin Bulletin — March 1918. New Zealand,] High Commissioner for — Patent Office Journal, Dec. 1917. Statistics for the Dominion of New Zealand, 1916. Pharmac utical Society of Great Britain — Journal for March 1918. 8vo. Photographic Society, Royal — Journal, Vol. XVIII. No. 3, March 1918. Quekett Microscopical Cluh—Jo\ivnsd, Series 2, Vol. XII. No. 77, 1915. 8vo. Robertson, T. Brailsford — The Utilization of Patents for the Promotion of Research. Royal Botanical Society— J onvnal, March 1918. Royal Engineers' Institute — Journal, Vol. XXVII. No. 3, March 1918. Royal Society of Arts — Journal for March 1918. 8vo. Royal Society of London — Philosophical Transactions, A, Vol. CCXVI. Nos. 540-541 ; B, Vol. CCVIII. No. Proceedings, A, Vol. CXIV. No. 659, March 1918. Scottish Geographical Society, Royal — Scottish Geographical Magazme, Vol, XXXIV. No. 3. 8vo. 1918. Smithsonian Institution — Miscellaneous Collections, Vol. LXVIII. Nos. 6, 7, 8 & 10 ; Vol. LXIX. No. 3. 8vo. Report on Progress and Condition of U.S. National Museum, June 30, 1916. Annual Report of the Smithsonian Institution. 8vo. 1916. Societd degli Spettroscopisti Italiani—^lem.ovie, Nov.-Dec. 1917. 4to. Southern Slav Bulletin— Yol. XXXVI. Feb. 1918. United States Department of Agriculture — Journal of Agricultural Research, Vol. XII. No. 57, Feb. 1918. United States Department of Commerce — Magnetic Tables and Magnetic Charts, 1915. United States National Academy of Sciences — Proceedings, Vol. IV. No. 2, Feb. 1918. Washington National Academy of Sciences — Proceedings, Vol. IV. No. 1, Jan. 1918. 8vo. Western Society of Engineers — Journal, March, June, and Sept. 1917. Zoological Society of London— Proceedings. 8vo, 1917. WEEKLY EVEXINCt MEETIXG, Friday, April 12, 1918. Dr. Henry E. Armstrong, LL.D. F.R.S., Vice President, in the Chair. Professor E. C. C. Baly, F.R.S. Absorption and Phosphorescence. [No Abstract.] 276 The Use of Soap Films in Engineering [April 19, WEEKLY EVENING MEETING, Friday, April 19, 1918. General E. H. Hills, C.M.G. R.E. D.Sc. F.R.S., Secretary and Yice-Presideiit, in the Chair. Major G. I. Taylor. The Use of Soap Films in Engineering. [Abstract.] The similarity, first noticed by Prof. Prandtl, between the equations representing the strains in a twisted bar of any section and the deformation of a membrane stretched uniformly over a plane boundary of the same shape as the cross-section of the bar, and deformed by the action of a uniform pressure, has been used to find the strains in twisted bars in cases where they cannot be calculated. The uniformly stretched membrane used in the experiments was a soap film, and films were projected on the screen in such a way as to illustrate, by means of Prandtl's analogy, the principle features of the strains in twisted bars. In this way it was shown that the strain at an internal corner becomes infinite, while that at an external corner vanishes. As an example of the usefulness of the method in solving prac- tical problems in engineering, the amount by which it is necessary to round off the internal corner of an L-shaped beam in order that the strain may not become too great when the beam is twisted, was worked out by means of soap films. Apparatus designed for measuring the soap films was shown. Some of the results obtained from the measurement of soap films are not easy to understand when applied to twisted bars. Some gelatine models were exhibited and projected on the screen which showed how the strains arise in these cases. [G. I. T.] 1918] Food Production and English Land 277 WEEKLY EVENING MEETING, Friday, April 26, 1918. The Hon. Richaed Clere Paesonh, M.Inst.C.E., Vice-President, in the Chair. Sir a. Daniel Hall, K.C.B. F.R.S., Permanent Secretary, Board of Agriculture. Food Production and English Land. The war has given us a new anxiety about our food supplies and a new interest in British agriculture as the only source of food if the work of the enemy submarines, a form of blockade that had never been contemplated, attains its aim even partially. To understand our position with regard to food production to-day we must go back to the history of British agriculture for at least forty years. Half a century ago British agriculture was easily pre- eminent, whether as regards its production from the soil, the excellence of its live-stock, or the organisation which was put into the manage- ment of the land. Then in the late seventies the great simultaneous development of the new lands of America and of ocean shipping coincided with a run of bad seasons at home and a steady apprecia- tion of the gold standard. From all these causes combined prices of agricultural produce fell, and continued to fall all through the eighties and well into the nineties, until by 1894-5, the lowest point, farmers were ruined wholesale. If they survived they saw their capital reduced to the lowest ebb ; landowners found their income from land down to the vanishing point, and could neither sell nor let, for all confidence in farming as a business had disappeared. From 1895 prices began to turn and continued to improve up to the date of the war, for a year or two before which farming had become a reasonably prosperous industry, and land was again in demand, though new capital was still to seek, so thoroughly had public confidence in agriculture been destroyed by the course of events within everyone's memory. Farming had revived, but viewed at large it was a system that attained only a low average of production, low utilisation of capital and low rents. As there were plenty of rich men in the country land was in demand for its amenities, but not as an income-producing investment. What had happened during that period ? How had men read- justed their business to the new conditions ? Some by altering the character of their production, by growing materials that escaped from the full brunt of foreign competition, milk instead of corn ; but in the main men had reduced their expenditure, cheapened their methods. Vol. XXII. (No. 112) u Sir A. Daniel Hal [April 26, and above all economised in labour by laying down to grass all land that was costly in labour or speculative in yield. Rents had, of course, been reduced, but men had to make a saving that was far greater than all the rent ; the labour bill was the big item of expenditure which could be cut at, and grass land needs but a quarter or even a tenth of the labour that is used on the arable. A few^ men brought science and skill to bear and cheapened their production by intensify- ing it, but such men were rare because they could find in other industries a better market for their enterprise ; for the majority Lawes' dictum holds, " High farming is no remedy for low prices." The chart (Fig. 1) shows the trend of events during these fateful 1870 Fig. 1. years — here is the line showing the cause — the cash returns from the corn and meat produced from an average acre of arable land, dechning from Si. 10s. in 1875 to bl. in 1895. Here is the line showing the area of arable land in England and Wales, declining from a maximum of 14 million acres in 1872 to lOi millions in 1913. Here are the number of men engaged in agriculture, 1,270,000 in 1871, 950,000 in 1901, just over 1 million in 1911. Lastly, here is the w^ages curve ; in spite of the diminishing returns from the industry the competition of the towns for workers had caused the average weekly rate of cash wages to rise from 12s. 6d. in 1870 to 15s. in 1900, and over 16s. in 1913. Here (Fig. 2) are the live- 1918] on Food Production and English Land 279 stock curves for England ; sheep have declined with the arable land, for in England sheep are largely fed on the arable ; cattle have increased ; above all dairy stock have grown in number. In Scotland and Ireland no such great change had taken place, though the arable land has declined, and in Scotland the proportion of temporary grass reckoned as arable land has increased, yet these countries being at the outset more concerned with stock than corn have maintained their position. How had the production of food been affected ? E70 mo 1890 1900 1910 19' 15 -^--" \ \ 13 12 11 (0 ■^ ^^ ■ ^;, "^i\^ *•*. . \ "^ ^\^ '■••V, ~'\ ^ 1 \y- 9 8 i ^ y J 1 1 Fig. 2. At first sight the change seems all right : corn had been exchanged for beef and milk ; the nation got the richer food and left to other nations the output of cheap raw materials like wheat ; the farmer was better off by concentrating on the more profitable market. This is plausible enough until you come to consider quantities, then an immense falling off in gross output l^ecomes apparent. In the first place any change to animal products from vegetable means waste when the consumer is down near the line of bare sub- u 2 280 Sir A. Daniel Hail [April 26, sistence. The animal has to live on readj-grown food and is a bad converter ; the pig which is the best haloitually eats six or seven pounds of' barley meal for every pound of pork he furnishes, and fat cattle consume at least twenty pounds of essential food for each pound of beef they lay on. Of course much of this food was such as human beings do not eat, grass or roots, but some was always potential human food, and the land which grew the cattle food might have grown human food. And this brings us to the second point : the absolute production from grass land is much below that from arable land, perhaps only a third on the average if both are set to produce meal or milk, less than a twentieth if the grass produces, as it only can, animal products, while the arable is turning out human food of a vegetable nature. Consider an acre of ordinary grass land ; it will produce in a year 150 lbs. of mutton, or perhaps 200 gallons of milk, but if planted with potatoes the excess of crop oyer seed may be expected to be 5 tons at least. Moreover, with a little bustling from manures and cultivation the 5 tons of potatoes can be made into 10 ; but it would be far more diflBcult to double the pro- duction of the grass. To take another example more in the line of general practice, land under a rotation will produce 1000 11). of corn per acre, and out of the straw and the roots and clover that occupy part of the land will grow the same amount of meat as would have been produced from the whole land had it been under grass. So the laying doATu of land to grass that went on during the years 1872-1'J15 did not mean the exchange of corn for an equivalent of meat and milk, but a dead loss of production of food. The loss is somewhat disguised in the chart you have seen illustrating the changes in the numbers of cattle, because that took no account of the increasing dependence even of our live-stock upon imported cattle foods. At tiie end of the period, for the five years 1909-13, the imported cattle foods consumed in the United Kingdom amounted to over G million tons per annum— barley, oats, rice, cakes, molasses, etc. (see Table I.). It was all concentrated food, and translated into meat in the ratio of 7 to 1 it represented 900,000 tons of meat, or one-third of the whole amount of meat consumed in the country. Considered more nicely on its energy value it was equivalent to, and if properly used would have produced, 29 per cent, of the whole of the meat, milk, eggs, poultry and dairy produce grown in the United Kingdom. So even the grass land did not make all the animal food we counted as the result of the change in our farming ; one quarter at least was the outcome of imported feeding stuffs. And in what sort of a position had these changes — less arable land, less production, more population — landed the country at the outbreak of war ? Table II. shows the Royal Society's Committee's estimate of the amounts and origin of the food consumed by our population for the vears 1909-13. We were producing in all 42 per cent, of the food 1918] on Food Production and English Land 281 Table I. — Consumption of Fodder in the United Kingdom, 1909-13 (Thousand Tons). Gross Weight Dry Weight Grown in U.K. Imported For Production :— Wheat offals . Maize Oats Barley . Beans, etc. Brewers' grains, etc. Oil cakes . Other foods 2,500 1,700 3,500 980 500 450 1,200 450 440 2,250 420 300 240 1,760 1,500 750 420 150 160 1,100 380 Roots, etc. Grass and hay . 44,500 15,000 5,200 13,000 21,850 6,220 For Maintenance : — Grass (as hay) . Straw 50,400 38,000 4,700 42,700 72 per cent, of productive fodder of U.K. origin. 91-5 per cent, of total fodder of U.K. origin. Table II. — Consumption of Human Food in the United Kingdom, 1909-1913. Metri c Tons Thousands Energy per cent, of Total Total Home Imports Home , Imports Cereals 4,865 1,010 3,855 7-2 ; 27-4 Meat .... 2,685 1,615 1,070 10-5 7-0 Poultry, eggs, etc. 331 170 161 0-4 0-4 Fish .... 848 715 133 JO-8 0-2 Dairy produce . 5,232 4,704 528 9-2 7-0 Fruit .... 1,271 341 930 0-3 1-8 Potatoes and vegetables 5,482 4,788 694 8-0 i 1-5 Sugar, etc. 1,657 1,657 — 13-0 Cottage, farm and garden i produce . . ./ 3,330 3,330 — 5-2 — 41 58-3 282 Sir A. Daniel Hall [April 26, we consumed. Of meat we produced 60 per cent, of our consump- tion ; both of wheat and bread, which represents ?0 per cent, of the food of the people, we only grew one-fifth of what we consumed. What a position for a nation at war with an adversary that can make a bid to cut off our supplies ! And Germany is making that bid in spite of what we held was our overmaste^'iug fleet. Let us think for a minute of what onr neglect of agriculture, our contentment with the position of being importers of half our food is costing us. First of all, we may be cut off from our food, may have to stop fighting because we have not enough to eat. It has only become perceptible in this last year that the food supply in the whole world is limited ; there is not an inexhaustible reserve for us to draw upon, and external supplies are running short. Even if we escape that last despair we have to use a large proportion of the strength of our navy, strength that is wanted for fighting purposes, to protect the entry of food ships. Again, we have to pay for the food in foreign countries, pay at enormously enhanced rates at a time when we want to retain every penny within our own islands. Our food bill forms the most onerous of debts to a nation at war, debt to a foreign creditor. Food, too, must be tlie first charge on our shipping, and shipping is the limiting factor in this war. Suppose the shipping we must fill with our food were now free to bring American soldiers and their food to our help in France ! What could we do to meet the situation ? The answer is plain — plough up our grass land and get back to the state of 1872, or even a more productive condition. But here is seen the full measure of the danger into which we have fallen ; when land is put down to grass the land is still there, but before long the means of ploughing it up are gone — the men have left for other occupations, the horses are gone, ploughs, harness, buildings are lacking, sometimes even the knowledge of arable cultivation has been forgotten. If you let a building go to ruin it will not be ready for occupation at an hour's notice, still less will an organisation, a society, begin to function again. Still, what has been done can be done. But for the first two years and more of the war it was not thought worth while to make any determined attempt to reconstruct agriculture and grow more food at home, so great was the sway of the old pre-war conception that agriculture was done for in this country, and that it was useless, even wrong, to try to grow our oAvn food. But, late as it was, in January of last year the campaign for increased food production was set on foot under Mr. Protliero with Sir Arthur I^ee as his lieutenant in command of the fighting forces. But you cannot step twice into the same river ; as agriculture depends upon men, and the men available in 1917 were fatally less than those still free in 1914, the power to effect a wholesale change was gone. Still the aciiievement of the Food Production Department has been enormous. This year we are 1918] on Food Production and English Land 288 going to have from three-quarters to a million more acres of wheat in England and Wales than the 2h million we had last year, and more than two million acres of permanent grass land have been ploughed up for this year's cropping, a recovery of two-thirds of the arable land that has been lost since 1872. To this we must add that a good deal of the temporary grass which occupies part of the arable land has this year been replaced by food crops, so that with the additions that Scotland and Ireland have been able to make there will probably be as much land under food crops this year in the United Kingdom as there was in the seventies. You will understand I am speaking approximately and on estimates, for the exact returns have not yet been collected. It is a great performance ; if I say that twice as much has been done as Lord Milner's Committee silting in 1914 thought was possible within the period, and that estimate was regarded as over sanguine, I perhaps give you an idea of the magni- tude of the task. But we are here to think of the future as well as of the present. I have said enough I hope to convince you that Britain must have a strong agriculture, must use her land to produce food, if she is to be safe as a nation in future. How are we to ensure that ? I do not contemplate that we should become self-supporting in the matter of food. I do not even wish us to grow all our own wheat. When war is over we shall revert to our old standards of profit, and men will produce meat or milk, asparagus or fruit, as pays them best. But we must have more arable land, another six or eight million acres, and we must have more. men engaged upon the land, so that when the crisis comes, as it may come again, we can throw all our acres into the production of essential food, enough to support us through the years of trial. AVith this easily possible amoi^nt of arable land we could be self-supporting for several years if we ate up our stocks of cattle, sheep and pigs, and used our land to an ever- increasing extent for the production of human food only. Our policy then must be directed towards more arable land, more men engaged in cultivation, greater responsibihty for the user of land. We have taken the first steps in that direction by the Corn Pro- duction Bill of last year. We cannot hope that men will adventure on the risk of arable farming unless they are free from the danger of the disaster that overtook the last generation of farmers. Hence the guaranteed prices of the Corn Production Bill ; the State will pay a bonus on the production of wheat and oats if the world prices fall below a certain level. It is an insurance that the State deliberately enters into in order to make sure that the arable land is maintained. Nor will men stop on the land unless their living is guaranteed. Before the w^ar the agricultural labourer only stopped upon the land because he was too depressed to look for any better paid employment; as far as they were capable the younger ones were not staying. The Corn Production Act entails a minimum wa^e. Mr. Prothero v\as 284 Food Production and English Land [April 26, bold enough to fix it at 25s. a week ; for the present the County Wa^es Committees are beginning with 30s. Lastly, the Corn Pro- duction Act takes power to ensure the proper user of the land ; if a tenant will not farm properly, or a landlord prefers game to corn, he can be turned out and someone put in who will employ the land in the national interest as well as his own. Ear-reaching principles these, revolutionary in their economics ; but have they any sound financial basis ? The land has after all to pay either for arable cultiva- tion or minimum wages ; can the land pay for these ideals ? Time is too limited to go far into that question. I will only lay before you one consideration. The agricultural labourer before the war, as Mr. A eland has pointed out, did actually produce more stuff net out of which he and his master had to be paid than did the industrial worker, the cotton-spinner, or the steel-maker. His output was worth about 100?. a year net, out of which his wages had to be paid. The average farmer in England was in fact living upon the earnings of five or six men ; he wanted a big return per man because he employed so few. Here, then, are the openings for economy in the new order : better organisation so that the man has not to carry so big a fraction as a master ; better efficiency so that the output of the man is greater. Time does not permit of the consideration of these latter points, organisation and efficiency. Here we should all agree that education and research have their part to play in the reconstruction, as great, if not greater, than the fiscal and legislative matters of which I have been speaking. "We began with considering that the nation must grow food in order to survive as a nation : we end with the concep- tion that the nation must grow men with brains if it is to have food. [A. D. H.] 1918] Annual Meeting 285 ANNUAL MEETING, Wednesday, May 1, 1918. Sir James Crichton-Browne, M.D. F.R.S., Treasurer and Vice-President, in the Chair. The Annual Report of the Committee of Visitors for the year 1917, testifying to the continued prosperity and efficient management of the Institution, was read and adopted. Twenty-three new Members were elected in 1917. Sixty-two Lectures and Nineteen Friday Discourses were de- livered in 1917. The Books and Pamphlets presented in 1917 amounted to 299 volumes, making 513 volumes (including Periodicals bound) pur- chased by the Managers, a total of 812 volumes added to the Library in the year. Thanks were voted to the President, Treasurer, and the Secretary, to the Committee of Managers and Visitors, and to the Professors, for their valuable services to the Institution during the past year. The following gentlemen were unanimously elected as Officers for the ensuing year : — Presidext— The Duke of Northumberland, K.G. P.C. D.C.L. LL.D. F.R.S. Treasurer — Sir James Crichton-Browne, M.D. LL.D. D.Sc. F.R.S. Secretary— Colonel B. H. Hills, C.M.G. RE. D.Sc. F.R.S. Managers. Visitors. Henry A. Armstrong, LL.D. F.R.S. 1 K. A. Wolfe Barry, M.Inst.C.E. Sir William Phipson Beale, Bart., K.C. I Sir Wm. H. Bennett, K.C.V.O. F.R.G.S. M.P. I John G. Bristow, M.A. Sir James Mackenzie Davidson, M.B. CM. John F. Deacon, M.A John A. Fleming, D.Sc. F.R.S. Percy F. Frankland, LL.D. F.R.S. J. Dundas Grant, M.D. F.R.G.S. Donald W. C. Hood, C.V.O. M.D. w. B. Gibbs, F.R.A.S. H. R. Kempe, M.Inst.C.E. I„. ,„ ,^^^_,_,_ The Rt. Hon. Lord Kinnaird, K.T. D.L. ^m. J. Gow, M.D. F.R.C.P. Sir Chas. Nicholson, Bart., M.P. LL.B. \ W. A. T. HaUowes, M.A. The Rt. Hon. Clere Parsons, M.A. Sir Alexander Pedler, CLE. F.R.S M.Inst.C.E. Hugh Munro Ross, B.A. Edward B. Poulton, LL.D. F.R.S. i ■J°^, q>,,^ tt p J. Emerson Reynolds, M.D. F.R.S. ^°''P^ ^^^^^ ^•^• The Rt. Hon. Lord Rothschild, F.R.S. ! ^°^^ Strain, M.Inst.C.E. The Rt. Hon. Lord Wrenbury, P.C. M.A. I Sir Henry Wood Edward Dent, M.A. Sir James J. Dobbie, LL.D. F.R.S. John A. W. DoUar, F.R.S. E. 286 Sir George Greenhill [May ;>,, WEEKLY EVEXING MEETING, Friday, May 3, 1018. Sir James Crichtox-Browxe, J.P. M.D. LL.D. F.R.S.. Treasurer and Vice-President, in the Chair. Sir George Greenhill. The Spinning-Top in Harness. " To those who study the progress of exact science, the common spinning-top is a symbol of the labours and perplexities of men wha had threaded successfully the mazes of planetary motion. [A sly dig at Xewton, I fear, in his struggle with Precession.] The mathe- matician of the last century [the eighteenth], searching through Nature for problems worthy of his analysis, found in the toy of youth ample occupation for the highest mathematical powers." These are Maxwell's words, reprinted in his Collected "Works, I. p'. '24:S, from his memoir on " A Dynamical Top," and here is the top, designed to show off the results of his theory. The toy of youth is shown in a collection here on the table. But to make the motion visible to this audience, we have chosen some on a larger scale, as this 5 2 -inch wheel of Mr. C. V. Boys's Otto bi-di-cycle. The point of the stalk is placed in a small cup, and the wheel is spun by hand. Dynamical similitude, as well as geometrical, is obtained by making the rim speed proportioual to the square root of the diameter ; so that here a slow rotation, about one revolution a second^ will be enough, contrasted with the 20,000 revolutions a minute m a gyro-compass, or 2,500 per second of the rifle bullet — tbat is, 150,000 per minute. The ordinary toy is too small to be seen at a distance, and a string must be used to spin it, to give velocity enough. A glance at the length of his string will show us when the operator will bungle — foozle the spin. This will be apt to happen if the string is longer than this, half the stretch of the arms — a fathom. Here's the cheap- jack's secret, selling this toy gyroscope here. The attention to reach is the great secret in boxing. The master buttons on the gloves of the novice, and standing up with hands behind his back he invites attack : — " Hit me ! — as hard as you can. Kill me, if it pleases you ; and it does'nt hurt me ! " How mortify- ing to find that he is'always just out of reach, drawing his head back quite a short way ! The master teases her by quoting the advice in his Latin grammar, how to fight the girl as he was taught as a boy — " Rixa, 1918] on The Spinning-Top in Harness 287 si rixji est, ubi tu pulsas, ego vapulo taut am " ("A fight where I hold out my head, for von to whack it.") Grasp the stalk, and brandish it, with the wheel at rest. Xo gyroscopic effect is felt : the wheel is inert. But give it a spin first, gently at a start with the novice, as the result will take him by surprise when the stalk is brandished. It flies to one side or the other. I avail myself here of the priviletje of addressing a learned audience, and so employ some of the technical jargon of our science. Represent the angular velocity and momentum of the spinning-wheel by a right-handed screw vector, as also the axis of an applied couple. By a vector that is right-handed we mean one such that the direction of the vector is the advance with a right-handed screw propeller. Then if the wheel is swung | j^^^,^^^^. .A an angular momentum is communicated about an axis drawn to the < i^., >, and the axle swerves the same way Vl^r^ [ unless prevented by a couple given by the hands, represented by an axis drawn jfiQtvnwardr Swuncr to the VIK^ i, ansfular momentum is communicated about a ° ( left y ^ (downward) • ^ ^^ ^ (down ) -^ • <- v.^ < 1 > axis, and the axle swerves < >, and reuuires to be ( upward j ' ( up i' ^ held < T \ ( by a couple with axis to the < i°,., >. With two screws on a ship or flying-machine they are generally spun opposite ways, so one of them will be left-handed. On a left-handed screw these directions are reversed, and we should get into confusion. Better, then, keep to the right-handed screw of ordinary practice, in any popular explanation. These are influences felt in a flying- machine, especially if provided with a Gnome revolving motor — a spinning-top in harness. The name Gnome seems to have been anticipated by Pope, in his lines " Know, then, unnumbered Gnomes around thee fly, The light militia of the lower sky," in the poem of the " Rape of the Lock." Putting the helm (joy-stick the airman calls it) of the flying machine to port, as a sailor would say, a couple is called up from the rudder tending to turn the head to starboard, and the couple axis is downward, and the nose of the machine dips. To ascend, the helm must be put to starboard. But to turn the machine to < „ ' ' i by utilizing the gyroscopic domination, a horizontal rudder must be used, and its helm put < > vertically. 288 Sir George Greenhill [May 3, Thus the top in harness is like the Irish pig, in Professor Perry's simile, who cannot be persuaded to accompany his master to market except by steerino^ him sideways into the ditch, a veritable tour-de- force— "transferring forces round the corner," in the title of the pamphlet on the Sperry Gyro-Compass. This sidelong force makes its appearance in the electrodynamical equations, and is called the gyroscopic term in consequence. The wooden ball on this wheel was fitted originally as a protec- tion for the head underneath when the wheel was suspended from the ceiling. The ball comes in useful here as showing the influence of the rounding of the point of a top in enabling the top to rise, when free to wander about the floor, and not constrained in this small cup. It is the friction of the ball-point causes the top to rise, but ultimately kills out the rotation. We try to avoid in these experiments the hideous unreality of perfectly rough and perfectly smooth, in the school-book jargon, by spinning the top either in the small cup or else on the rounded point on the floor. The wheel comes to rest when the rim reaches the floor, and to study the motion when the axle makes a greater angle with the zenith, and moves about in the neighbourhood of the nadir, we turn to this other apparatus, an ordinary 2«-inch bicycle wheel — the axle screwed into a steel stalk — a short length of rifle barrel, suspended from a lug on a bicycle hub, allowing motion in altitude and azimuth. An ordinary hook attachment would serve as well, I believe, if well oiled. The hub is fastened in this iron bracket, bolted to the underside of a beam or sleeper, and this should be heavy enough to absorb vibration — not a thin board, or lath, or little stick as I found them trying in Rome with the present I had made of the apparatus. The model is easily constructed, as the complicated parts, wheel and hub, can be bought cheap, ready made. Spin the wheel by hand ; and project the axle, to obtain any desired gyro- scopic motion— undulating, looped, cusped. The analytical mathematical theory is abstruse, and requires the elliptic function, in a much more complicated form than for the simple pendulum in plane oscillation of finite extent. But here are two simple cases of motion where the solution is quasi-algebraical, and so may interest the mathematical student present : — I. Hold the axle out and project it horizontally, without spinning the wheel, when the motion is that of a spherical pendulum, a simple plummet at the end of a thread. II. Spin the wheel, and allow the axle to fall from rest at a cusp at an upward angle so that the axle reaches the horizontal in its lowest position, rises again, and so continues. The exact interpretation is rather delicate of the rotation of the wheel about a moving axle. Thus, although we start with the wheel at rest on the axle, we cannot turn it by twirling the axle. But moving the axle round in a conical way to rest again, we find that 1918] on The Spinning-Top in Harness 2^9 the wheel can be turned round on the axle, to an extent proportional to the conical angle. And so we answer the challenge of Aristotle, to turn a sphere round that is perfectly smooth, or spitted on a perfectly smooth axle along a diameter. Anyone can show this off with a pencil held between the finger and thumb. The angles employed by Euler in 1750, and denoted by 0, \b, <^, are still in use in modern analysis. 0 For altitude or nutation. x^r For azimuth or precession, clamping th-e wheel with the thumb. 04 Lieut.-Colonel A. G. Hadcock [May 24, (2) The pressure rises and forces the copper driving band which surrounds the projectile to give rotation into the rifling grooves. (3) The charge still burns, and the pressure forces the shot along the gun. (4) The charge is completely burnt. (5) By the expansion of the hot powder gases, the shell is forced further along the bore and out of the gun. One of the most important of these processes is the forcing of the driving band into the rifling, and the subsequent behaviour of the charge depends greatly on the initial resistance of the driving band when it is forced into the rifling grooves. The greater this resistance, the larger will be the proportion of the charge burnt before the band is fully engraved, and the higher will be the pres- sure when the band is fully engraved. Noble and xA^bel, in their original paper read before the Royal Society in 1H75, gave a most important law which governs the relation between the density of the charge and the maximum pressure produced in a closed vessel. This law, formulated from the results obtained by experiment with black powder, still holds closely for all modern powders. The law as originally stated is '■ 1 - aA where p is the pressure in tons per square inch, R constant found by experiment, and A the gravimetric density of the charge. This gravimetric density is an artillery term, but it simply means the specific gravity of the charge as compared with water, supposing it to be spread uniformly throughout the volume of the vessel. It is based on the Act of Parliament gallon of 10 lbs. of water at G2° F., which should occupy a space of 277*8 cubic inches, or 1 lb. of water should occupy 27-73 cubic inches. Thus if C is the capacity in cubic inches of the vessel, and iv the weight of the charge in pounds, 0 then the weight of water the vessel would contain is ' — pounds, 27-73^ ' and the gravimetric or specific density, i.e. the ratio of the weight of the charge to the weight of water the vessel would contain, is 27-73 ?z' C If we consider the volume occupied by w lbs. of water as the unit of gravimetric or specific volume, then the number of such volumes in our closed vessel or in a gun of capacity C is . = 1 = '' A 27-73//' so that V corresponds in a gun to a definite length of travel of the shot. 1918] on Internal Ballistics 305 Noble aud Abel's formula Ijecomes a much more convenient expression by introducing the volume notation instead of that of densitv, viz. : — R p = . V — a With the old black powder a was supposed to represent the volume of the solid part of the charge which always remained in the vessel, and so reduced its capacity, after the powder had been exploded. The space occupied by this solid mass was 57 per cent of the volume of the original powder. Clausius and Van cle Waals, experimenting on air and other gases at pressures and temperatures far below those obtained by Sir Andrew Xoble, arrived at more complicated formulas, but involving very similar constants to those of the Noble and Abel formula. AVith colloidal smokeless powders, such as cordite when fired in closed vessels, the a term still makes itsappearance, although there is no solid residue after the explosion. Now, the unit of volume we have dealt with up to the present is that due to the whole charge, but as the powder burns gradually it is evident that the unit of volume will vary as the charge is consumed. If we put v', the varying unit of volume, as that due to any fraction z of the charge which has been burnt, then if 8 is the density of the solid powder compared with water, i.e. 1 • 58, we have for the actual available space, the capacity of the vessel less the content in cubic inches of the unburnt powder, viz. : — 0-27-73(1-2)^' o C - 27-73 (1 - 0) ^ so that v' = — if we write ^ = '^ 27*73 z IV . . . , 1 , V - a It IS lound that v - a = z where v is the gravimetric volume, supposing the whole charge had been - converted into gas, and a is a constant commonly called the CO- volume. This constant may be described generally as proportional to the space occupied by unit-volume of gas if compressed by infinite pressure. This formula is true both for the closed vessel of constant capacity and for the gun with which the capacity varies according to the travel of the shot in the bore. 806 Lieut.-Colonel A. G. Hadcock [May 24, Most artillerists have so far treated the problem of internal ballistics either {a) as if the gun was a closed vessel for each position of the projectile, as in Centerval's and Mansel's methods, or (b) that the pressure, for each position of the projectile, bears some definite relationship to the pressure which would have been developed had the charge been burnt in a closed vessel of capacity equal to that of the chamber of the gun. This method of treatment has been adopted by (losset, Heffernan, Charbonnier, and others. Both these assumptions require some qualification, because in a closed vessel no linear motion is given to the charge, while in a gun a considerable amount of energy is absorbed by the charge having to be put into motion. Thus we find that the pressure on the breech of the gun is higher than that on the projectile. The pressure on the base of the shot is that due to putting the shot alone into motion, while the higher pressure on the breech is due to the additional work required to be done in putting also into motion the weight of the gas or charge. Direct experiment proves this to be the case, and usually the difference in pressure on the breech and on the base of the shot amounts to between 1 and 2 tons per square inch. By assuming that the pressure falls uniformly from breech to the base of the shot and that the mean velocity of the gases and uncon- sumed part of the charge is four-tenths to one-half that of the projectile, we can prove that the following relation holds between the pressure on the breech and that on the shot — Pressure per square inch on breech _ 4 ?^ ^ , ^ Pressure per square inch on shot 10 W where iv weight of charge in pounds ; W the weight of the shot ; and / the factor of effect. Another way of looking at this is to remember that when a column of fluid under pressure is put into motion a certain amount of the pressure is lost. The amount so lost depends on the velocity. In our case we have the gas under high pressure. Part of it is in contact with the shot and moving at the same velocity as the shot ; the remainder has a gradually less linear motion, until at the breech end of the gun there is no relative motion. It follows then that the forward part of the gas, which has a considerable velocity, will have less pressure than that part in contact with the breech end of the gun. In a gun the space behind the projectile continually increases as the projectile travels along the bore ; thus each portion of the gas as generated may, for our purpose, be considered to expand according to the law p iv' - aj = k (a constant), and do work on the shot. In doing so it would lose heat, but at the same time the charge continues to burn and additional heat is given to the already generated gases ; thus our hypothetical expansion is neither adiabatic nor is it iso- thermal. For simplicity we suppose that no heat is imparted to the 1918] on Internal Ballistics 307 walls of the bore, but any loss from this cause is accounted for in the factor of effect. Jf now we consider that some definite fraction of the charge has been converted into gas, the gas expanding according to a definite law {v' - a.y = p I j = constant : as though no more of the charge would be burnt, but that the proper amount of additional heat from the unburnt part of the charge is imparted to the expanding gases— then a set of curves can be drawn somewhat similar in character to those of Fig. 13 in Clerk Maxwell's " Theory of Heat," 1897. Thus curve 1 may mean that a fraction of 1/10 of the charge has been converted into gas ; curve 2, 2/10 of the charge, and so on up to 10, when the whole has been converted into gas. These curves are lines of equal combustion, but for shortness may be called Isopyric Lines. The trace of each isopyric line shows the expansion curve of the gas then generated, on the supposition that the remainder of the gas remained unburnt. For each isopyric line, if the position of the shot in the gun is known — that is to say, if the volume is known — then the pressure can be at once determined, or if the pressure is known, the position of the shot can be found. If it is assumed that after a fraction z of the charge has been burnt no further combustion takes place, then the energy of the expansion of the powder gas generated from this fraction z will follow the usual adiabatic law. But since the rest of the charge continues to burn, additional heat is imparted to the already generated gases, so that the assumed expansion will not be strictly adiabatic, but will follow some law intermediate between adiabatic and iso- thermal expansion. For adiabatic expansion the power to which the volume function must be raised is 1*41 for most gases, but according to actual experiments on petrol engines, a better value for these engines is 1 • 23, while with the high pressure used in guns the usual value has been taken at 1*2. For isothermal expansion the volume function power is of course 1. AVe may consequently accept the relation P (^7= a constant where the power lies between 1 • 2 and 1 • 0. It has been found that the mean value 1 * 1 gives results closely approximating to those obtained in actual practice. The constant k depends on the resistance offered by the driving band on the shot («) during the initial engraving and (h) during the subsequent motion along the bore of the gun. 308 Lieut.-Colonel A. G. Hadcock [May 24, ONOOag U3d x33;j 'AJ.lDOn3A « .cussing this very question of the long poem in modern times, suggests several reasons for the frequency of its failure. One is this. The modern mind is not content with a narrative of events, however splendid and moviuL- ; it craves for some profounder interpretation of a world which grows ever more complex and limitless to our understanding. The trend is inward. We are interested in the movement of the souls and minds of men, in spiritual victory and catastrophe, rather than in action for its own sake. It is Hamlet himself, the subtle workings of his mind and its reaction on his will, who enthrals one generation after another ; not the external story, with its murders and violences. Yet it would seem hardly necessary to point out that it is through his actions that Hamlet reveals himself ; and what we really demand is that action should be significant, should be the inevitable issue of charac- ter in movement. If action is suppressed and neglected in a long poem, the salient outlines become flat and tame. There is a loss of vital energy, of concrete definition ; the sense of mass, the sense of movement, are alike missing. Poems like the "Excursion" or " Paracelsus " show in their different ways how much reflection and analysis may overweight the poet and fatigue the reader. I agree with Mr. Bradley that this preoccupation with the inner life is one main cause of the rarity of success in modern poems on the great scale. I agree also with most of what he says about another cause. That is the modern poet's freedom, his unchartered freedom. We live in an age when the history of the world and the surface of this planet hive been explored and made known in a way that hitherto has been impossible. To a poet seeking a subject all times and countries are open. He has but to choose. Yet this necessity of choice, this unlimited field, how baffling and distracting they can be ! For he feels instinctively that he must choose some subject at once related to his own nature, and to the lives of those 322 Mr. Laurence Binyon [May 31, around him. Far easier was it for the poet who lived in a more circumscribed society, in a smaller world, where his relation to his public was definite and assured. The limitation to an expected cycle of subjects concentrated his energy into certain channels, and gave it force and volume. The Greek tragedians worked in those condi- tions. But in times like ours the poet has to establish a relation with his audience, an audience potentially vast but actually vague. He seeks a theme which, in Shelley's words, shall be relative to the age, and in practice he finds that a hard quest. If he consults the public, the public will probably say to him : Surely the present is more interesting than the past. Why not boldly take your theme from the life we are living now ? I agree that no time is more interesting than the present ; and I think most poets would like, if they could, to create something splendid and significant out of it. Perhaps some day it will be done. But for the land of poem of which I am speaking, a concrete poem, whether narrative or ostensibly dramatic in form, there are disabling conditions in a purely contemporary theme. Two great modern poets. Whitman and Yerhaeren, have sung the actual scene before them ; and they have given us eyes to see realities, ignored and despised as ugly, Avith a new illumination. Yerhaeren has made wonderful j^oetry out of that great and disturbing phenomenon of our times, the flight from the country to the towns ; he sees it as a kind of elemental struggle between two forces. But Yerhaeren does this by means of separate poems, lyrical in form, which make up a sort of whole, it is true, but are not the same as a single coherent and concrete creation. And Whitman, too, is lyrical from beginning to end. He seems to be always announcing the new great poem of democracy, which never actually comes. It is open to anyone to say that forms like the epic are dead, and that the type of poetry which we find in AVhitman or Yerhaeren, or some other, has taken its place. But the creative instinct in poets will, I think, always urge them at least to attempt something more, to deal with character in action on the grand scale. Now, for one thing, modern life, and especially modern demo- cratic life, does not tend to throw up great characters in relief, rather it submerges them in the stream. And poetry like Whitman's is almost entirely concerned with the variegated mass of average men and women ; it is indiscriminate and anonymous. Before the war we might, perhaps, have been apt to scoff at Whitman's glori- fication of the average man. We saw him as we met him in the ordinary ways of life, and found him uninteresting. But it is the average man who is the hero of this war ; there is no doubt of that. He it is who has given us a new reverence for common humanity ; what he has l)orne and done surpasses imagination to conceive. Yet it is just the numbers, the namelessness, of the common man that so deeply impress us. And if the poet takes him for a hero — I am speaking now from the practical point of view — what is he to do ? 1918] on Poetry and Modern Life 323 If he takes an individual and makes of him a living character, the more his story is occupied with him as a person, the less will the significant sense of that swarming anonymous mass of human beings, of which he is but a unit, pervade the poem. If he remain a type, he will be colourless and lack Hfe. And in any case, so much of him must be passive ; he is caught into great actions and events, of whose issue and meaning he is ignorant. Here are difficulties possibly not insurmountable, but certainly intimidating, since the poet will seek above all things for vigour of design and salient relief in his theme, and all this tends to a blurred outline. The material does not run naturally into the mould. Rather it is the modern novel which is the natural, the inevitable form for such a theme. But suppose that we avoid the common man, however much a hero. Suppose we take individual characters whose actions are really pregnant and far-reaching, in whom the asserted will makes for happiness or calamity. If we take known persons, we cannot deal with them freely ; they are too familiar on the surface, so that a hundred irrelevant criticisms and curiosities are roused in the reader, and yet in their inner selves, that which has most interest for the poet, they are too little known. The portrayal will either be sup^^r- ficial or fanciful. And if we take imaginary persons of our own creating, w^e are again in the field of the modern novel. All the detail of modern life, the detail we want to have forgotten, for the sake of the spiritually significant, the inner reality, suggests itself inevitably to the reader. Prose can handle this easily ; but it is a clog on poetic movement. I think these reflections are enough to suggest why poets have instinctively avoided in poems of a large scale actual contemporary life. Let us go back for a moment to the example with which we started. You remember how " Don Juan " opens — " I want a hero ; an uncommon want, When every year and month sends forth a new one." How truly might we echo that in these days ! Then follows a list of eminent men of action of Byron's time, including Wellington and Nelson, all dismissed as " Exceedingly remarkable at times, But not at all adapted to my rhymes." They are rejected for " our ancient friend, Don Juan." It is true that Don Juan is re-created and made a contemporary of the poet's, but through what remote scenes of adventure and romance he is led !. What is really contemporary and relative to the age is Byron's mock- ing comment, not only on his theme, but on every matter that comes into his head. The poem grows less and less concrete as it proceeds ; it is unfinished, but we hardly notice that, it has so little of objective 324 Mr. Laurence Binyon [May 31, shape and form. And, in truth, one might ask whether it is reallj as relative to its age as Shelley's " Prometheus," which under a mythic disguise embodies the hopes of that rarefied yet passionate ideahsm which was so characteristic of the time. With all its splendour and its incomparable lyrics, Shelley's " Prometheus " does not rank as a solid richly structural achievement with the great poems it attempts to rival. Yet I do not think it fails because its nominal theme is an old Greek legend. I think snch a theme is likelier of success than such a theme as Wordsworth took in his " Excursion," which, again, though sown with beauties and often exquisite in its felicity of language, makes as a whole a flat impres- sion ; the characters are so stationary, and their reflective talk so much a monotone. Of all modern English poets Keats had the gifts most adequate for the task. He had grandeur and simplicity of conception ; his imagination was sensuous and concrete. But he broke off his " Hyperion " because the subject dissatisfied him ; he tried, in recasting it, to give the subject a more real relation both to himself and to his age — to make it significant, and in a deep, though not superficial sense, modern. It is certainly a misfortune for us in England that we have so little in the way of national myth and legend to draw upon ; for in the far-descended stories that come down from a nation's childhood there is usually embodied something innate and permanent which belongs to the character of the race ; and, being fluid rather than fixed, they are material which every generation of poets can take up and fashion anew and adapt to its own uses. They are removed from actual history, so that the impertinent antiquarian cannot intrude his idle stickling for the facts of time and place. We have the Arthurian legends, it is true, but these have come to us in a version already modernized and mediaevalized, so that the truth of their pristine features is overlaid with the colouring of an artificial age, with courtly codes and romantic decorations, from which it is hard now to extricate the vital elements. But if anyone doubt the power of mythic stories to stir the blood of the race in whose imagination they were born, let him consider what AVagner's treatment of the cycle of Northern legends has meant to the Germany of our day, or what the Irish legends, resuscitated in recent years and handled in poetry by Mr. Yeats and his followers, have meant to the youth of Ireland. It is to such materia] as this that a creative poet turns by instinct. He wants to be at a certain distance in time from his theme, because he wants to grasp it clearly as a whole, because he does not want to be distracted by externals and irrelevant, but none the less insistent, associations ; because he wants to concentrate on human spirits in action ; because he wants figures of a strong outline and a pregnant type ; because he wants to get away from the Avorld of fact to the world of imaginative reality. He does not go to the past for the sake of what is past, but for the sake of what is permanently Hving. He 1918] on Poetry and Modern Life 325 asserts the continuity of human history, just as, in the h'ght of science, confirming his own intuitions, he will assert more and more, I believe, the continuity of all life, the continuity of the universe. I may seem to have expressed a despondent view on the possi- bilities in England for a poet who seeks to create on a large scale a work that shall be no refuge of romance, no product of a cloistered studio, however beautiful, but something essentially related to his own age. But poets have their ways of discovering themes. I believe in the future of Enghsh poetry. Only the other day a long poem was published which found a theme at once new and relative to the age — I mean the "Song of the Plow," by Mr. Maurice Hewlett— a poem sustained with so intense an energy that it conquered matter the most intractable, a poem of good augury and fine incentive, telling of the past and breathing of the present. Mr. Bradley, in the lecture I referred to, tentatively suggested one hampering condition for the modern poet who w^ould celebrate great actions — that his life was private and sequestered and un- acquainted Avith the world of action. Of our younger generation that can no longer be said. Rather it might be said that the world of action and stress is too much with us, that poets lack the stillness in which, according to Ooethe, genius grows best. But let us have faith. We cannot predict what forms poetry will take, nor what themes it will choose. Poetry, genuine poetry, will always be new, because it brings — what is so much more precious than novelty of subject — the eternal freshness of unique personality, the poet himself. [L.B.] Vol. XXII. (No. 112) '62i] General Monthly Meeting [June 8, GENERAL MONTHLY MEETING, Monday, June 3, 1918. Sir James Crichton-Browxe, M.D. F.R.S., Treasurer and Vice-President, in the Chair. The Chairman announced the decease of His Grace the Duke of Northumberland, K.G., President, on May 14. The following Resolution of condolence was submitted to the Members, and unanimously passed : — The Members of the Royal Institution of Great Britain, in General Monthly Meeting assembled, desire to express to His Grace the Duke of Northumberland their sympathy with him and his family in the loss which they, as well as the Royal Institution and the Country at large, have sustained by the death of his father, the late Duke. They desire to record their grateful sense of the invaluable services rendered to the Royal Institution during the late Duke's Membership of 34 years ; a period in which he held office as Manager on four occasions, and as the President for 19 years. His Grace's active interest in the progress of Science, which it is the object of the Royal Institution to promote, together with His Grace's nobility of character, have lent distinction to its proceedings during an eventful period of its history. The Duke of Northumbierland, Arnold Jacob Cohen Stuart, William Rintoul, were elected Members of the Royal Institution. Keport from the Managers, June ;>, 1918 : — . The Managers reported that the Fullerian Professorship of Chemistry would become vacant on June 7, and that in pursuance of the Deed of Endowment the election of a Professor by them would take place on July 1 next. The Chairman declared, in the terms of the Bye-Laws, Chap. 4, Article 2, there was a Vacancy in the Office of President through the decease of His Grace the Duke of Northumberland, K.G., and a vacancy in the Office of Visitor through the decease of Sir Alexander Pedler, and at the next General Meeting, on July 1, the Vacancies will be filled in accordance with the said Bye-Law. The Presents received since the last Meeting were laid on the table, and the thanks of the Members returned for the same, viz. : — FROM 27i« Secretary of State for India— Geological Survey : Records, Vol. XLYIII. Parts 3-4. 1917. Memoirs of Department of Agriculture, Botanical Series, Vol. IX. No. 2. Nov. 1917. 8vo. Agricultural Research Institute, Pusa. Journal for April, 1918. Svo. Ii)l8] General Monthly Meeting 327 Accademia dei Lincei, Reale, Roma — Classe di Scienze Fisiche, Matematiche e Natural!. Atti, Serie Quinta : Rendiconti. Vol. XXVII. 1° Semestre, Fasc. 6-7. Classe di Scienze Morali, Serie Quinta, Vol. XXVI. Fasc. 11-12, e indico del Volume. 8vo. April, 1918. American Chemical Society — Abstracts for April, 1918. American Geographical Society — Review for April, 1918. American Philosophical -Socic^i/— Proceedings, Vol. LVII. No. 1. 1918. 8vo. American Physiological Society — Journal for March, 1918. 8vo. Astronomical Society, Royal — Monthly Notices for April-March, 1918. 8vo. Bankers, Institute of — Journal for May, 1918. 8vo. British Architects, Royal Institute o/— Journal, Third Series, Vol. XXV. No. 7 May, 1918. 4to. British Astronomical Association —Memoirs, Vol. XXII. April, 1918. 8vo. Journal, Vol. XXVIII. No. 6, April, 1918. California, Leland Stanford Junior University — Bulletin, No. 95. Register for 1916-17. Annual Report of the President, 1916. The Pathology of Nephritis. Bone and Joint Studies. I. The Genera of Fishes. The Use of Ye in the Function of Thou. Emerson. A Study of the Magmatic Sulfid Ores. Carnegie Institution of Washingtoyi — Annual Report, 1917. 8vo. Chemical Industry, Society of — Journal for May, 1918. 8vo. Chemical Society — Journal for May, 1918. 8vo. East India Association — Journal, N.S., Vol. IX. No. 2, April, 1918. 8vo. E^fZi^ors— Astrophysical Journal for May, 1918. 8vo. Athenaeum for ^lay, 1918. 4to. British Dental Journal for May, 1918. 8vo. Chemical News for ^lay, 1918. ito. Chemist and Druggist for May, 1918. 8vo. Church Gazette for May, 1918. Dyer and Calico Printer for ]\Iay, 1918. 4to. Electrical Review for May, 1918. 4to. Electrical Times for May, 1918. 4to. Electricity for May, 1918. 8vo. General Electric Review for May, 1918. Horological Journal for May, 1918. 8vo. Illuminating Engineer for March, 1918. 8vo. Junior Mechanics for May, 1918. Law Journal for May, 1918. 4to. Model Engineer for Mav, 1918. 8vo. Nature for May, 1918. '4to. New Church Magazine for May, 1918. 8vo. Science Abstracts for April, 1918. 8vo. Wireless World for May, 1918. 8vo. Zoophilist for May, 1918. 8vo. Florence Bihlioteca Nationale — Bulletins for Jan.-Feb. 1918. 8vo Franklin Institute —ZouxnoX, Vol. CLXXXV. No. 4, April, 1918. 8vo. Geographical Society, i^oyaZ— Journal for May, 1918. 8vo. Harvard College Astronomical Observatory — Annual Report for 1917. Linnean SocieiS?/— Journals : Zoology, Vol. XXXIV. No. 225, May, 1918; Botany, Vol. XLIV. No. 296, May, 1918. 8vo. London County Council — Gazette for May, 1918, 4to. London University — Gazette for May, 1918. 4to. Marine Society — Statement for 1917. Magazine for May, 1918. z 2 328 General Monthly Meeting [June 3, Mcterorological O/^zce— Weekly Weather Report for 1917. Weekly Weather Reports for Jau.-March, May, 1918. Daily Readings for March, 1918 Geophysical journal for May, 1917. Milford, Humphrey, Esq.— -The Periodical. April, 1918. Nizamiah Observatory, Hyderabad — Astrographic Catalogue, Vol. I. 1918. 4 to. Peru : Guerpo de Ingenieros de Minas — Boletins, Nos. 86 and 88. 8vo. 1918. Pharmaceutical Society of Gi-eat Britain— Journal for May, 1918. 8vo. Photographic Society, Royal — Journal for May, 1918. 8vo. Public Library, City of Pos/on— Bulletin, Vol. XI. No. 1, Third Series. 8vo. 1918. Rontgen Society — Journal for May, 1918. 8vo. Boyal Colonial Institntc— United Empire for May, 1918. 8vo. Royal Cornivall Polytechnic Society — Annual Report, Part III. 1917. Royal Society of .4r/s — Journal for May, 1918. 8vo. Royal Society of Edinbiirgh—Fvoceedings, Vol. XXXVIII. Part 1. 8vo. 1918. Royal Society o/ Lon^ion— Proceedings, A, Vol. XCIV. May, 1918. 8vo. Year-Book, 1918. 8vo. Scottish Geographical Society, Boyal— J onrnsil, Vol. XXXIV. No. 5, May, 1918. Bvo. Societa degli Spettroscopisti Italiani — Memorie, Vol. VII. 2nd Series, March- April, 1918. 4to. Society for Experimental Biology and Medicine — Proceedings, Vol. XV. No. 5, Feb. 1918. 8vo. South African Association for the Advancement of Science — Report for 1916. 8vo. United Service Institution, Royal — Journal for May, 1918. 8vo. United States Department of Agriculture — Experiment Station Record, Vol. XXXVIII. Nos. 1-2, Jan. -Feb. 1918. 8vo. Journal of Agricultural Research for March, 1918. 8vo. Monthly W^eather Review, Vol. XLVI. No. 1, Jan. 1918. Photograph of a Group of Scientists : Brewster, Faraday, Wheatstone, Tyndall and Huxley. Presented by Mr. Fredk. Du Cane Godman, M.R.I. F.R.S. United States National Academy of Sciences — Proceedings, Vol. IV. No. 4, March-April, 1918. 8vo. United States Naval Observatory, Washingto7i — American Ephemeris and Nautical Almanac, 1920. 8vo. Washington, Library of Congress — Report for 1917. Western Society of Engineers — Journal, Vol. XXII. No. 8, Oct. ; No. 10, Dec. 1917. 8vo. 1918] The Romance of Petroleum 329 WEEKLY EVENING MEETING, Friday, J-iine 7, 1918. The Hox. Richard Clere Parsoxs, M.Inst.C.E., Vice-President, in the Chair. Sir Boverton Redwood, Bart., D.Sc. F.R.S.E. M.R.I. The Romance of Petroleum. PETR0LEU3I is detlned in the Petroleum Act of 1871 as including " any rock oil, Rangoon oil, Burmah oil, oil made from petroleum, coal, schist, shale, peat or other bituminous substances, and any products of petroleum, or any of the above-mentioned oils." The scientific definition is even wider, embracing natural gas, solid bitumen and ozokerite. It is, therefore, an appropriate introduction, for the suggestion of which I am indebted to the Fullerian Professor of Chemistry, to recall that it was in the Laboratory of this institution, in 1825, that Faraday examined the liquid which separates when the gas made by the destructive distillation of fixed oils is subjected to compression, and isolated from it the hydrocarbon benzene, as well as several other compounds of carbon and hydrogen. In 1815, John Taylor was granted a patent for a process described as producing " inflammable air or defiant gas applicable to the pur- poses of giving light " from vegetable or animal oil, fat, bitumen, or resin. This oil-gas, compressed by a method patented by Gordon and Heard in 1819, was supplied by a company having the title of the London Portable Gas Company. It was contained in vessels having a capacity of two cubic feet, which were delivered to the premises of consumers, and returned when empty to be refilled. The liquid which separated when the gas was compressed into these cylinders was that which Faraday examined. It is not reasonable to assume that whilst he was ascertaining the chemical constitution and properties of what was actually synthetic petroleum, Faraday can have realised the importance of the part destined to be played by these hydrocarbons in peace and in war. Nevertheless, his extended reference to what he describes as the remarkable action of sulphuric acid upon the compounds of carbon and hydrogen which he had isolated, and his subsequent paper on the mutual action of sulphuric acid and naphthalene, appear to indicate that he may have had an intuitive perception of the valuable indus- 330 Sir Boverton Redwood [June 7, trial developments in the manufacture of dyes, wliich after many- years followed bis classic researches. In the same year, Faraday also published tlie results of his exami- nation of caoutchouc, and showed that this substance is mainly a compound of carbon and hydrogen. Eleven years later, Edmund Davy, a consin of Sir Humphry Davy, discovered the gaseous hydrocarbon which we now know as acetylene. The account of his discovery which he gave at the meet- ing of the British Association in 183() was as follows : "Early in the present year the author, in attempting to procure potassium, by strongly heating a mixture of calcined tartar and charcoal in a large iron bottle, obtained a black substance which readily decomposed water and yielded a gas which, on examination, proved to be a new compound of carbon and hydrogen." It is interesting to note the relation between these respective researches of Faraday and Edmund Davy and the rival theories of the organic and inorganic origin of petroleum, to which further refer- ence will be made. As an illustration of unexpected issues of scientific investigation, I may remark, though I must do so in carefully guarded terms, that a hydrocarbon, largely employed in early low-temperature research work in this Institution, is now being made use of by t!ie enemy in one of the most abhorrent forms of modern offensive warfare. There are many obvious allusions to the occurrence and uses of petroleum in the Old Testament scriptures. Thus, in the account of the building of the Tower of Babel we are told that '• slime had they for mortar," the word " slime " in our version being given as " bitumen " in the Yulgate. Again, in Genesis xiv. 10, the Vale of Siddim is described as " full of slime pits," and on this account it has been suggested that the destruction of Sodom and Gomorrah may have occurred through the sudden outburst of petroleum in this region. This has led Mr. W. H. Dalton to remark that the destruc- tion of these cities, and our recent conquests in Palestine, were effected by the same agency, with the essential difference that in the latter case the flow of the oil was under control. The Vale of Siddim, with its slime pits, is no more ; even its precise position is a matter of doubt, but the pitch spring of the Ionian island of Zante. described by Herodotus in 450 B.C., may still be seen. Here is a photograph (Fig. 1) of this spring of petroleum taken in 1890, whilst my guide was in the act of inserting an olive branch into the spring, and withdrawing it dripping with the oil, the flow being, apparently, as almndant as it was -2,300 years previously. I may add that drilling for petroleum in the locality has not resulted in obtaining any yield of commerciid importance. Long before the Ghristian era, the drilling of wells for natural gas, with a view to its use as a source of heat in evaporating brine. 1918] on The Romance of °etroleum 881 was a recognised industry in China, and it is worthy of note that the instruments employed bear a close resemljlance to modern drilling appliances. Petroleum occurs in greater or less quantity throughout the whole range of strata of the earth's crust, from the Laurentian rocks to the most recent members of the Quaternary period, but it is found in quantities of industrial importance almost wholly in the compara- tively old Devonian and Carboniferous formations, on the one hand, or in the various divisions of the comparatively young Tertiary rocks, on the other. Its origin has been the subject of much controversy among dis- tinguished geologists and cliemists who have devoted special study to the subject. Berthelot and Mendeleeff lent the weight of their authority to the theory that petroleum was derived from metallic Fig, 1,— Zante. Oil Spring. carbides lying far beneath the porous strata in which the oil is stored, and made the attractive suggestion that the process might be conceivably in operation at the present time. The view is now, however, universally accepted that petroleum is of organic origin, and that it has been produced from vegetable matter and tlie lower forms of animal life, chiefly aggregated during the geological periods referred to, when favourable conditions, which did not persist through the whole period, occurred. In certain places, for instance in Karabugas Bay, on the eastern side of the Caspian Sea, in Sweden, in Sardiniii, and in the eastern part of the Mediterranean, there is some conversion of organic matter into petroleum actually to be seen in progress at the present time. It is not difficult to account for the formation of adequate deposits of the necessary material. In the comparatively deep and quiescent 3;')2 Sir Boverton Redwood [June 7, water along the margin of the land in past ages there would be abun- dant opportunity for the deposition not only of the remains of marine animals and plants, but also of vegetable matter brought down to the coast by the water-courses, and the changes which the earth has undergone would result in the burial of these substances under sedimentary mineral matter, the deposits thus formed being ultimately, as the result of further alterations in the earth's surface, often found occupying positions far removed from the sea, and sometimes beneath immense thicknesses of subsequent deposits. The instance of Karabugas Bay, already referred to, affords an excellent illustration of the manner in which the necessary accumulations of marine remains probably occurred. In this land-locked bay organic matter is being constantly conveyed from the open sea through a very shallow entrance over the bar, and as the water of the bay is rendered more strongly saline by the active evaporation which occurs in this torrid region, all life is quickly destroyed, whilst at the same time putrefactive decomposition of the remains is prevented. AVhilst, however, as I have said, there is general agreement as to the organic origin of petroleum, there is considerable difference of opinion as to whether the oil is in all cases indigenous to the strata in which it is found, and as to whether the conversion of the organic matter was practically completed when the strata were formed, so that the age of the rocks is that of the petroleum found therein. There are distinguished advocates of the view that petroleum results from the action of a slow continuous process of distillation of the material yielding it, accompanied by a transference of the product to strata lying above those in which its formation originated. According to some, this process occurred at a definite and distant time in the past, long subsequent to the formation of the petroliferous strata ; but in the opinion of others it may be in progress at the present time. The question is not one of academic interest only, for it obviously would be of vast importance if it could be demonstrated that our stores of petroleum, which are being depleted with alarming rapidity, might be replenished. I fear, however, that there is no ground for such an encouraging anticipation. As Lesley, the United States geologist, remarked in 1886, "I am no geologist if it be true that the manufacture of oil in the laboratory of nature is still going on at the hundredth or the thousandth part of the rate of its exhaustion. And the science of geology may as well be aban- doned as a guide if events prove that such a production ;of oil in Western Pennsylvania as our statistics exhibit can continue for successive generations. It cannot be. There is a limited amount. Our children will merely, and with difficulty, drain the dregs." Probably each of the views expressed in relation to the organic origin of petroleum has some elements of truth in it, and it is reasonable to assume that a substance so varied in chemical and physical characters has not in all cases been created under precisely 19l«] on The Romance of Petroleum 338 the same conditions or from an exactly similar source. On the whole, however, the balance of evidence appears to point to the conclusion that the petroleum which we now find in the Palaeozoic and Tertiary rocks is of substantially the same geological age as the rocks themselves. It is, I believe, uncertain whether man existed on the earth before the close of the Tertiary period, though there ai3pears to be no valid reason why he should not have, but there is abundant evidence of the existence of the human race in the following Quaternary period. The advent of man may, therefore, have been coeval with the completion of the petroliferous formations. The following two slides are reproduced from illustrations in Pouchet's work on " The Universe," and may be considered to give some idea of what the surface of the earth was like during the two principal periods of the creation of petroleum. The first is an imaginary view of a forest of the Carboniferous period. At this time the earth had long passed the stage of being " without form and void." The elementary and compound substances of which it is made up had ceased to exist countless ages before in their original condition of incandescent gases and vapours ; the contractile move- ment of the earth had resulted in the formation of valleys on the outer crust of which the condensed aqueous vapour collected as seas ; and the land was covered with luxuriant vegetation. In the fore- ground of the picture is a swamp which, presuming its proximity to the sea-coast, may be regarded as a typical birthplace of petroleum. Pouchet says of this period that the whole surface of the land was covered with strange and dense forests, where proudly jeigned a host of plants the representatives of which at the present day play but a very humble part. These vast primeval forests, which the course of ages was to annihilate, sprang up on a heated and marshy soil, which surrounded the lofty trees with thick compact masses of herbaceous aquatic plants, intended to play a great part in the formation of coal. This rich covering of vegetation, which extended from pole to pole, was sad and silent, as well as strangely monotonous. Xot a single flower enlivened the foliage, not one edible fruit loaded its branches. A sky, ever sombre and veiled, oppressed with heavy clouds the domes of these forests. A wan and dubious light scarcely made visible the dark and naked trunks ; on all sides reigned a shadowy and indescribable hue of horror. The echoes remained absolutely mute, and the branches without a sign of life, for no air- breathing animal had as yet appeared among the savage scenes of the ancient world. Of only one reptile have remains been found, but in the seas were abundant fish and shelled molluscs. The next slide indicates the conditions which prevailed during the Tertiary period, when the formation of our stores of petroleum was being completed. In this epoch peaceful and luxuriant nature was, as Pouchet expresses it, animated for the first time with inoffen- sive mammals, some of singular forms, others of colossal size. The 834- Sir Boverton Redwood [June 7, vegetation of this period exhibits a great analogy with the present flora of the temperate regions of the northern hemisphere, and in the seas were new races of molluscs in great quantity. Not less important than the provision of adequate supplies of organic matter to be transformed into petroleum is that of a suitable rock-formation for its reception and conservation. For the latter we need a porous stratum, such as coarse-grained sandstone or con- glomerate or dolomitised limestone, with an impervious cover, such as that provided by fine-grained shale. In addition, in order that the wells drilled may furnish individually a large yield of oil, it is essential that the petroliferous strata should have been caused to assume an anticlinal structure. Under these tectonic conditions any natural gas accompanying the oil accumulates at the crest of the anticline, whilst the oil occupies the flanks, and water is found in the synclines. The gas often occurs at a pressure of many hundred pounds on the square inch, and it is obvious that in these circum- stances a well drilled into the flank of the anticline may produce an oil fountain. The geographical distribution of petroleum is no less wide than the geological, as will be seen from the next slide, whereon the principal occurrences are marked in red, but the deposits mainly occur along well-defined lines, often associated with the mountain ranges. This is chiefly due to the formation, in the elevatory process, of minor folds, which have arrested and collected the oil in richly- productive belts, between more or less barren areas, in the manner already referred to. There are, however, but few of the localities indicated as petrol- iferous which contribute largely to the world's output of petroleum, estimated for last year as approximately 70,403,128 metric tons. This is shown in the following slide. The predominant contributor, as will be observed, is the United States, ^\hicli furnished no less than 64*74 per cent of the estimated total for 1017, the others in order of importance being : Russia, Avith 1 3 • 2G per cent ; Mexico, with 11-37 per cent ; the Dutch East Indies, with 2*74 yjer cent; Roumania, with 2*08 per cent; India (Burma and Assam), with 1*61 per cent ; Persia, with 1 * 32 per cent ; Galicia, with 0*1)47 per cent ; Japan, with 0*615 per cent ; Peru, with O'oll per cent ; Trinidad, with 0*303 per cent ; Germany, with 0* 180 per cent; the Argentine, with 0 170 per cent; Egypt, with 0*094 per cent ; Canada, with 0 * 037 per cent ; Italy, with 0 * 002 per cent ; and other countries, with 0 • 006 per cent. It is nofc surprising that the flood of oil which has been poured out by the wells of the United States in ever-increasing volume since 1859 should now be attended by signs of the approaching exhaustion of the petrolifei-ous territory, and it has been estimated ]\v Dr. David T. Day that, at tlie present rate of increase of the output of petroleum, the known oilfields of that country will, on the basis liUS] on The Romance of Petroleum 3o5 of the minimum quantity of oil obtainable, be exhausted by the year 1935. It will be readily understood that the temporary storage and the transport to the refineries of so large a volume of crude oil as is represented by the annual output of over 70 million tons necessitates the provision of facilities on a scale of great magnitude. In the United States, and in many other oil-producing countries, the storage is effected in vertical cylindrical steel tanks, which are usually 00 feet in diameter by 'M) feet in height, whilst in Russia excavated earth reservoirs, often of great size, are also employed. It will assist us to realise what is needed if I give you some calculations which have been obligingly made for me by Mr. William Sutton. A veitical cylindrical tank 80 feet in height would need to be 10,952 feet, or a little over two miles, in diameter to hold the world's production of petroleum for last year. Such a tank would cover an area approximately three times that of Hyde Park and Kensington Gardens together. It would require a pipe 6 feet 2 inches internal diameter, with a rate of oil-flow of 8 feet per second, or two miles an hour, delivering continuously throughout the year, to transport the world's production by that means. The oil would fill over seven million 10-ton railway tank waggons. These woukl make a train of 28,()00 miles in length, considerably more than sufficient to encircle the earth at the equator, and such a train, running at 25 miles an hour, would take 46 days 16 hours to pass a given point. The world's production of crude petroleum is equivalent to 17 gallons pe?' c^pifa of the estimated population of the world. The pipe-line system of transport of the crude oil from the various oil-fields to the seaboard, where the chief refineries are situated, over a distance of several hundred miles, has been brought to great perfection in the United States, and there are now thousands of miles of trunk lines, up to 8 inches in diameter, in operation. The working pressure, owing to friction and to the elevation of sections of the line, is usually not less than 900 lb. on the square inch, and may rise to 1200 or even 1500 lb. The steel tubing employed, therefore, needs to be of exceptional strength, and the screwed couplings to be of special construction. The form of pump is of equal importance, for it must be such as to keep the column of oil in continuous and regular motion, as the concussion which would attend an intermittent flow would quickly have disastrous consequences. The oil-producing countries of the British Empire are India (Burma and Assam), the AVest Indies (Trinidad), and Canada, and those in the aggregate furnish only 2 per cent of the total given. Under these conditions the British Government is to be con- gratulated on having secured the control of the exceptionally prolific 336 Sir Boverton Redwood [June 7, oil-fielas of Persia. The circumstances in which this important acquisition, which is entitled to rank with Disraeli's purchase of the Suez Canal shares, was rendered possible are worthy of being recorded. Eighteen years ago, the late Mr. W. Knox D'Arcy obtained from the Persian Government a concession for the exploitation of petroleum over the whole of Persia, with the exception of the portion bordering on the Caspian Sea. Successful drilling operations were carried out at Kasr-i-Shirin, on the Turco-Persian frontier, and later the work of development was concentrated in an area about 150 miles from the port of Mohammerah, on the Persian Gulf. The results obtained exceeded the most sanguine anticipations, but the financial burden had become very great, pioneer work of this description in such a country being exceptionally costly, and if Mr. D'Arcy had subordinated his patriotism to his self-interest the concession would have been lost k) this country, for at this juncture he received tempting offers from Continental financiers, who were fully alive to the vast importance of it. Supported by Lord Fisher, Mr. Pretyman, the late Sir Gordon Miller and Sir Frederick Black, Mr. D'Arcy declined to entertain in any form the seductive proposals made to him, being determined that at whatever cost to himself the Persian oil-fields should remain under British control, and in 1909, with the powerful co-operation of the Burmah Oil Company and the late Lord Strathcona, the Anglo-Persian Oil Company was formed, with a working capital of £1,200,000. During the succeeding four years the Company carried out a comprehensive scheme of development, under the able guidance of Mr. Charles Greenway, and with the help, up to the time of his death, of Mr. C. W. Wallace. Drilhng was actively continued, a pipe-line was laid from the oil-fields to A])adan, on the Persian Gulf, where a refinery was erected, and a large amount of geological exploratory work was done. All this involved a large outlay of capital, and as the Comjmny's cash resources were l)ecoming exhausted there was again a risk of the introduction of foreign control. At this juncture Mr. Greenway was fortunate, with the help of Sir Francis Hopwood (now Lord Southborongh), in inducing Mr. Winston Churchill, then First Lord of the Admiralty, to give his personal attention to the position and prospects of the Couipany, with the result that the British Government purchased a controlling interest in the undertaking for the sum of £2,200,000, and nominated two directors, Lord Inchcape and Admiral Slade, to serve on the Board. This action was taken in the face of considerable opposition, both in the House of Commons and outside, and statements were freely made that the Government had made a disastrous bargain, but at the last Annual General Meeting of the Company Mr. Greenway had the gratification of being a])le to announce that the profits had already become so large that if the Government wished to dispose of their holding he was prepared to find purchase^-s for it for not less than six million pounds sterling, and perhaps eight million. Of the 1918] on The Romance of Petroleum 387 vast area of presumably oil-ljearing territory ^vhich the Company controls only a small part has been brought into active development, but this has proved to be remarkably rich, one of the wells Ijeing reported at the meeting to have so far yielded about 1,750,000 tons of oil, and to be still producing as freelv as ever, with practically no diminution in the gas-pressure governing the flow. In the British Isles, as is well known, there is a flourishing industry in the mining and distillation of Scottish shales as a source of mineral oil and ammonia. This industry owes its existence tu James Young, of Kelly. In 1847, Young's attention was directed by Plavfair to a stream of oil flowing' from the top of a coal-workim^r at Alfreton, in Derbyshire. From this oil he succeeded in extractiny-, on a commercial scale, paraffin-wax, lubricating -oil, r.nd burning-oil. The supply of the raw material being soon exhausted, Young attempted to imitate the natural processes by which he believed the oil to have been produced, by the action of gentle heat on coal, and in 1850 made his invention the subject of his celebrated patent for " obtaining paraffine oil, or an oil containing paraffine. and paraffine from bituminous coals by slow distillation."" The process was ex- tensively carried out in the United States, under licence from Young, until crude petroleum was produced in that country in such abun- dance, and at so low a cost, that the distillation of bituminous minerals became unprofitable. In this connexion it is interesting to note thfit in consequence of the approaching exhaustion of the oil-fields of the United States, attention is now being actively given to the utilisation as a source of oil of the immense deposits of bituminous shales known to exist in that country. The discovery of valuable seams of oil-shale in the early days of the Scottish oil-industry was not characterised by as intense an excitement as prevailed during the development of the older oil-fields of the United States, when sedate business men often suff'ered from an attack of " oil-fever," but was, nevertheless, not unattended by features of interest. This block of shale, carved into the form of a book, was presented to me twenty years ago by Mr. Stewart S. Robertson, with the following account of its history : "Some forty years ago my father had one morning a visit from a notorious poacher, who undertook, on payment of one sovereign, and the promise of fifty more, to show him something, and never again to poach on our property. The sovereign vv^as paid, and I was deputed to accompany him. On arriving at a certain point where a burn runs between high steep banks, he began picking up bits of what he told me was shale, and showed me a part of the burn which flowed over a smooth black surface of shale. At this time everybody was going shale mad, as Young had just commenced his now well-known works at Addiewell, about 3J or 4 miles, as the crow flies, from Tarbrax. the place of which I am writing. The poacher received 338 Sir Boverton Redwood [Jane 7, his £50, and never troubled us again. The next day I returned to the spot with a man provided with the necessary tools, and we soon dug a hole two or three feet deep, and took out some pieces of the shale, from one of which the ' book ' you have was made. We had numerous offers to lease the land, among them one from Young himself, but ray father selected Mr. Fernie as his tenant for 719 acres. Mr. Fernie at once commenced erecting works, but the difficultv of transporting machinery was very great, the site being on a wild moor, and before the works were quite completed Mr. Fernie died. Operations were continued by the executors. The Caledonian Railway made a branch line four miles long on to the property, and eventually the Caledonian Oil Company, Limited, became, and now are, the tenants." I have mentioned the work carried out by Young on the crude petroleum of Alfreton, and this leads me to refer to the prospects of obtaining free oil in quantity in this country. For many years there was an actual output of petroleum recorded in the General Report and Statistics relating to Mines and Quarries in the United Kingdom, issued by the Home Office. The annual output reached its maximum in 1893, when it amounted to 200 tons, valued at £4^8. It had fallen to 5 tons, valued at £12, in 1899, and was returned as nil in the following year. There was a recorded pro- duction of 8 tons in 1901, and 25 tons in 1902, none in the two succeeding years, 46 tons in 1905, and 10 tons in 1906, the principal locality of production for the latter years being Dumbartonshire. Since 1906 no output has been recorded. Apart from the production referred to, there have been discoveries of oil in this country from time to time, some of which were of a very doubtful character. An interesting occurrence of free petroleum was brought to my notice in 1892. It took the form of a sudden influx of some hundreds of gallons of light-coloured oil into a well which was the source of the water-supply of an isolated dwelling- house standing on high ground near Shepton Mallet. Another case, which is certainly genuine, is that of the oil-find in a test-boring made for coal at Kelham, near Newark. From this bore-hole, which at a depth of between 2-400 and 250(> ieet had penetrated a bed of porous sandstone, a flow of characteristic crude petroleum amounting to five or six gallons a day took place. The much-advertised dis- covery at Ramsey, near Huntingdon, cannot be included in the same category, for the oil, of which a specimen, together with one of the Kelham oil for comparison, is on the table, had unquestionably leaked from an adjacent store. It may be confidently asserted that in certain parts of Great Britain the geological conditions are consistent with the existence of valuable stores of petroleum, but doubt has been expressed as to whether the drilling operations which the Government has decided to undertake will be attended with success. It is, however, admitted 1918] on The Romanoe of Petroleum 339 that the only conclusive test is that of the drill. Some months ago Lord Cowdray publicly announced his belief that oil may be found in commercial quantities in Great Britain, and stated that his firm were prepared to spend £500,000 on exploration and development if certain areas were reserved to them. Even if we should be unsuccessful in finding free oil, we knc'W that we have abundant stores of bituminous minerals from which oil can be obtained by destructive distillation. For centuries petroleum has been raised from hand-dug wells in Burma, Roumania and Galicia. In the days when King Theebaw reigned in Burma the winning of petroleum by hand-digging in the Yenangyaung district was an important source of revenue. This model, constructed in Burma by native workmen, represents a scene in the oil-field, and it will be observed that women were largely employed in the surface operations. It ought to be liljerally sprinkled with crude petroleum to make it realistic. Here, imce Rudyard Kipling, East and West have met, in the use of the American kero- sene cans for the transport of the oil from the wells. Some of the wells are excavated to a depth of no less than 300 feet, which is the more surprising when it is borne in mind that owing to the presence of petroleum vapour even a young and strong man cannot continue the work for more than about five minutes. The diggers are lowered into and raised from the well by means of the windlass shown, and here is one of the implements which they use in loosening the earth overlying the rock in which the oil occurs. It consists, as will be seen, of a stout \^'ooden staff, shod with iron, the end of the shoe being notched. To break up hard rock when encountered an angular mass of iron is dropped into the well. The detritus is shovelled into baskets and raised to the surface by means of the windlass. The next slide (Fig. 2) represents a scene at the mouth of a well. In the foreground is a digger, with his mouth open, who has just com- pleted his short spell of work in the well and is recovering from the asphyxiating effect of the vapour. On his right is a digger about to take his place, with his eyes bandaged, so that he may be accustomed to the dim light at the bottom of the well and enabled to begin work at once. AVhen the oil-bearing formation has been penetrated the petroleum is brought to the surface in spherical earthen pots, the hauling being done by the women, who run down an inclined plane. The petroleum is carted from the wells in bullock-waggons, one of which forms a prominent feature of the model, to the river-side, where it is poured into the holds of Burmese sailing-boats, of which a model is on the table, and is thus conveyed down the River Irrawadi to Rangoon, where it is refined. The photograph shows a fleet of these boats moored in readiness to receive the cargo. This primitive system of production has been superseded by the introduction of modern methods of drilling, in which steam-driven machinery is employed. The system most largely adopted in. the 340 Sir Boverton Redwood [June 7, various oil-fields of the world is that which is known as percus- sion drilling. The plant consists of a tall pyramidal wooden, or occasionally steel, structure, sometimes as much as 80 feet in height, with an engine-house attached. This model, beautifully carved by Burmese natives, gives a good idea of the plant, notwithstanding the artistic disguise, for it is made to scale. The "string," as it is called, of drilling-tools consists of the " bit " or cutting-chisel, the " auger-stem," the " jars," and the " sinker-bar." Some idea of the nature of the work to be done may be formed when it is stated that the length of a standard deep-drilling Californian string of tools is over 60 feet and the weight 2^ tons. The bit alone, for a bore-hole of 23 inches diameter, of which a full-sized model, kindly made for i Fig. 2. — Burma, Oil Well. me by the Oil Well Supply Company, is in front of the lecture-table, has a length of 6 feet and weighs over a ton. The string of tools is suspended by a manilla cable or wire rope from one end of an oscillating beam, the other end of which is connected by a rod with a crank on a shaft driven by the steam-engine. It is thus caused to rise and fall, so that the bit delivers a series of blows on the rock at the bottom of the well, the tools being gralually lowered as the depth increases. The jars may be l)roadly likened to a pair of flattened links of a chain, and its function is to strike an upward blow when the bit l)ecomes jammed in the rock. From time to time the string of tools is drawn up into the derrick, and the detritus is removed from the borehole bv the use of a valved cvlinder, termed a sand- 19J8] on The Romance of Petroleum 341 pump. The next slide (Fig. 8) gives a view of the interior of the lower part of the derrick during drilling operations. The photograph shows the drilling appliances withdrawn from the well, in order that the sand-pump may be introduced. To exclude water, met with in upper strata, from the well, and to prevent caving, the well is lined with steel artesian tubing, and, as it is usually necessary to reduce the diameter as the boring pro- ceeds, the well may contain several concentric strings of such tubing. The drilling of petroleum wells has been brought to such perfec- tion that depths of a mile or more may be reached without serious difficulty in a moderate length of time, l:)ut the yield of oil needs to be considerable to render drilling to such depths a profitable under- taking. Four years ago there were in the Boryslaw-Tustanowice oil-field of Galicia sixteen wells of a depth of over 5000 feet, and one Fig. 3. — Interior of Derrick. was then yielding oil from strata which had been reached at 5873 feet, or nearly a mile and a furlong. Drilling operations in the tropical jungle are attended with exceptional difficulti< s of transport. The next two photographs (Fig. 4) are of scenes in the Digboi oil-field of Assam. It will be observed that the patient and intelligent elephant is here employed as a labourer, and that the derricks are thatched to protect the drillers from the sun's rays. Within recent years, the rotary system of drilling, in which a rapidly-revolving annular cutter, of the type indicated by the example on the lecture-table, is employed, has l)een largely adopted, with great saving of time when the formation is suitable for its use. It not infrequently happens that oil is met with on completion of the well under such high pressure, sometimes several hundred pounds on the square inch, that the flow is uncontrollable. Most of us have seen pictorial representations of the famous oil-fountains of Baku, Vol. XXII. (Xo. 112) 2 a 342 Sir Boverton Redwood [June 7, but less is known of similar occurrences elsewhere, which were of an even more remarkable character. The photograph projected on the screen is that of a fountain in the Grozni oil-field in the Northern Caucasus which began to floAv in August 1895, and was estimated to have thrown up during the first three days over 4,500,000 gallons, or about 18,500 tons, of oil a day. It flowed continuously, but in gradually diminishing quantity, for fifteen months, quickly destroying the derrick, and afterwards periodically. When I visited the spot in April 1897 there was still an occasional outburst of oil and gas. To save the enormous volume of oil ejected, an army of workmen was employed day and night in throwing a dam across the valley, so as to form a gigantic reservoir, as show^n in the next slide. This dam gave way, and a second was constructed below^ it ; a third, still lower down the valley, being afterwards added as a measure of precaution. Fig. 4. — Assam Oil Field. The huge lake of oil thus formed is shown in the next slide, which represents the scene looking up the valley towards the dam. Another slide depicts the impressive' appearance of a burning fountain on the Rothschild property at Bibi-Eibat. The loss in oil and damage to property during the ten days which elapsed before the fire could be extinguished was estimated at a million roubles. Probably the most sudden and violent of the outbursts of oil which have been experienced is that which occurred in 1908 on the San Diego property of Messrs. S. Pearson & Son (Lord Cowdray's firm) in Mexico. In the early morning of July 5 in that year oil was struck in a well known as No. 3, at a depth of 1824 feet. The pressure gradually increased, and in fifteen or twenty minutes the ground round the well began to tremble. In various places, some as far distant as 250 feet from the well, fissures appeared, through which oil and gas were emitted. One of these fissures extended under the 1918] on The Romance of Petroleum 843 boilers, and although the fires had been drawn the gas ignited. The flame was immediately communicated to the out-flowing oil, and the well burned for a period of fifty-eight days with an estimated loss of 3,000,000 barrels of oil. A photograph (Fig. 5) of the burning well is now on the screen. For the loan of this, and the two succeeding photographs, I am indebted to Lord Cowdray. The flames reached a height estimated at 1460 feet, with a maximum breadth of about 480 feet. So brilliant was the light emitted that at 9.40 p.m. on July 8 persons on board a vessel at anchor on the Tamiahua lagoon, a distance of nearly 11 miles from Fig. 5. — Mexico. Burning Well, the well, were able to read a newspaper by it. This is the more remarkable when it is considered that the approximate Umit of dis- tance at which an object 100 feet high is visible to a spectator at sea-level is a little over 12 miles, so that unless the light from the burning well had been reflected from smoke or cloud, only the upper part of the column of flame could have had illuminating effect at the distance recorded. Besides ejecting the large quantity of oil men- tioned, the well yielded a considerable volume of water, estimated to reach at times nearly 1,500,000 barrels daily. This great flow of liquid carried away from the sides of the well solid matter estimated approximately at 2,000,000 tons. On August 31 the flow of oil 2 A 2 344 Sir Boverton Redwood [June 7, temporarily subsided, and it became possible to extinguish the fire by means of sand pumped into the crater with centrifugal pumps. Oil September 26 the area of the crater was about 15,000 square metres, and on January 28 of the following year, about 117,600 square metres. The two following photographs show Mexican soldiers walking through the fissures caused by the eruption, and the crater as it appeared when the fire was extinguished. The deposit of ozokerite in Boryslaw, Galicia, is unique, although the mineral occurs in other localities in that country, as well as in Russia and in Utah. The Boryslaw^ deposit underlies a pear-shaped area, the central and richest part of which is about 50 acres in extent, but this is surrounded by an outer zone of less productive territory, which increases the area of the workable field to about 150 acres. The ozokerite occurs in veins varying from extreme tenuity to many feet in thickness. It is usually plastic, as shown by the speci- men on the table, and has evidently been forced up from underlying beds by lateral pressure, through fissures resulting from the local yield- ing of the marl to the compressive strain. The pressure which still exists is attested by the viscous flow of the ozokerite in the mines, and by the frequent distortion or collapse of the timbering of the galleries. As an illustration of this it is recorded that in one mine the perfora- tion by a miner's pick of a thin impervious stratum of rock forming the floor of a gallery resulted in the gradual appearance of a vertical stalk of ozokerite, which for a long time was replaced when it was removed. This curious appearance of growth gave the name of Asparagus Mine to the working. The mining of ozokerite was formerly carried out in the primitive fashion shown in this locally- constructed model by a large number of proprietors, each of w^hoQi had acquired mining rights over a small area which frequently included the dwelling-house. The industry was essentially a domestic one, for it was carried out by the whole family, the sons doing the underground work, w^hilst the wife and daughters assisted by working the windlass and blowing machine, and the father sat at a table and kept the accounts. It w^as the practice to sink a shaft to the ozokerite veins, and to drive from the bottom a gallery into the deposit, which was then mined by the pick. The great pressure exerted by the semi-fluid ozokerite necessitated very heavy timbering, and when I visited tlie locality in 1891 I saw timbers nearly a foot square which had been broken into matchwood by the strain to which they had been subjected. Sometimes the ozokerite suddenly burst into the workings and overwhelmed the miners, and it is reported that men have been unexpectedly raised from the bottom of the shaft to the surface of the ground by such an influx. The horizontal galleries could not be driven further than a few yards on account of the risk, and because of the proximity of the properties. Over the mouth of the well was fixed a windlass carrying a wire rope, to each end of which was attached a bucket used in drawing 1918] on The Romance of Petroleum 845 up the ozokerite, and in lowering and raising the miners. The descent was made by pi icing one f(;ot in the bucket and I olding on to tlie rope, the other being used in fending the bucket off the sides of tlie shaft. Owinu' to the sul)sidence and lateral movement of the ground, due to the removal of the ozokerite, the shafts did not long remain vertical, and the descent was not a pleasant experience. The miner wore a safety-belt, to which a rope was attached. Much inflammable gas was met with in the galleries, and safety-lamps were necessarily used. Ventilation was unsatisfactorily effected by means of a fan-i)lower. Within easy reach of the miner was a cord attached to a bell at the mouth of the shaft, by means of which he could summon assistance ; but notwithstanding the provision of the bell and safety-belt deaths by suffocation were not uncommon. The first effect of the inhalation of the gas produced a kind of intoxica- tion, which some of the miners appeared to find enjoyable. It is not surprising that work of this character, often conducted with insufficient capital, inadequate appliances, and imperfect organisa- tion, should have been attended with much unnecessary loss of life, especially when tlie somewhat reckless character of those engaged in it is taken into account. It was stated in 1871 that, among the 2000 underground workers then employed there were usually from 200 to 300 accidents yearly, nearly all of which were fatal, and that in some years the number of deaths was as great as 1000. The ozokerite candles which many of us can remember were n-ade from ceresin, a product obtained hy subjecting the ozokerite to destructive distillation in a current of superheated steam. These candles were specially suited for use in tropical countries, owing to the high melting-point of the material. Purified ozokerite has also been largely employed as a substitute f^r or adulterant of beeswax, which it closely resembles in physical properties, especially in the manu- facture of church candles, in cases where the employment of paraffin- wax is prohibited by ecclesiastical law. Crude petroleum varies greatly in character, as is shown by the representative collection of specimens from various parts of the world which is on the lecture-table, some descriptions being of pale colour and highly mobile, whilst others are almost black and viscid. The specific gravity appears to range from 0'771 to 1*06. As regards its chemical composition, petroleum consists essentially of carbon and hydrogen, together with oxygen, and varying amounts of nitrogen and sulphur. Pennsylvanian petroleum consists chiefly of a large number of hydrocarbons of the paraffin series, whilst naphthenes or polymethyl- enes are the predominant constituents of Russian petroleum. In some descriptions of crude petroleum, notably those of the Dutch East Indies, Persia, and Burma, aromatic hydrocarbons are largely present. These paraffins and naphthenes are very accommodating, in the 346 Sir Boverton Redwood [June 7, sense that they readily lend themselves to conversion, by dissociation, or " cracking," as it is termed, into other compounds of carbon and hydrogen, of lower boiling-point or higher volatility, which are so largely in demand at the present time in the form of motor-spirit. The conversion occurs when the oil is distilled under pressure or is brought into contact with highly-heated surfaces. The chemical changes which occur in these circumstances and the constitution of the products were investigated by Thorpe and Young many years ago. In 1888, I was privileged to be associated with the Fullerian Professor in experimental work which involved the construction of suitable apparatus for carrying out the process on a practical scale, and it was found that in order to obtain the best results it was necessary to effect the condensation of the vapour also under pressure. The process devised at that time is essentially the same as that which is now very largely carried out in the United States, w4th the object of augmenting the inadequate supplies of motor-spirit normally obtainable from the crude oil by fractional distillation. By carrying this treatment further it is possible to obtain aromatic hydrocarbons, and I have on the lecture-table specimens of the high explosive trinitrotoluene, or T.N.T., as well as benzene nnd dye-products, thus obtained from petroleum containing no aromatic hydrocarbons. The refining of petroleum, briefly described, consists in the classification of the hydrocarbons, by means of fractional distillation, into the various commercial products, including motor-spirit, lamp- oil, heavy fuel-oil, lubricating oils of various grades, and solid paraifin, and the subsequent purification of these products. The simplest form of fractionating apparatus comprises a still, of which a model is on the table, and a condenser consisting of piping, which may be coiled or straight. Of such an arrangement a photograph (Fig. 6) is now projected on the screen. It represents what is probably the most primitive petroleum refinery in the world, situated at Sherkat, in Mesopotamia, near the Tigris. The stills and condensers are plainly shown, and here again we see, in the foreground, the ubiquitous American kerosene can. This model represents a petroleum refinery of modern type, with dephlegmators interposed between the stills and the condensers, to effect the separation of the more readily condensable hydrocarbons. In the early years of the industry petroleum products were largely stored, and wholly distributed, in barrels and tin cases, but the system now universally adopted is that of storage and transport in bulk. The type of tank employed for the storage of the oil is shown by the model. These tanks are constructed of steel plates, and are often as much as 1)0 to 100 feet in diameter by 30 to 40 feet in height. The largest holds about 2,00(1,000 gallons. For the trans- port of the oil specially constructed tank steamers, which unfortunately are the objects of unwelcome attention on the part of the enemy's submarines, are used. These vessels, of one of which a sectional 1918] on The Romance of Petroleum 847 model is before jou, are with few exceptions driven by steam- engines, and as a rule the steam is raised by the combustion of oil fuel, but within recent years some have been built with internal- combustion engines, with resulting economy in fuel consumption. Of the later additions to the large fleet of such vessels, some are of great size, carrying as much as 15,000 tons of oil, but the more usual cargo capacity is from 5000 to 10,000 tons. The evolution of the tank steamer occupied many years. As far back as ISlx, Ludwig Xobel, the Swedish pioneer in the Russian petroleum industry, constructed the first of these vessels employed on the Caspian Sea in the transport of petroleum from Baku to the mouth of the Volga. At an earlier date, viz. between 11 -14:1. 1917. 8vo ; Nos. 52-56. 1918. 8vo. Contributions from Mount Wilson Solar Observatory, Nos. 142-146. 1917. 8vo. Chemical Industry, Society of -ZoViVnQ].,ZM\y-Oc,t. 8vo. 1918. Chemical Society — Journal for June Oct. 1918. 8vo. List of Officers and Fellows. 1918. 8vo. Chemistry, Institute of Great Britain and Ireland — Proceedings, Part 3. 1918. 8vo. Civil Engineers, Institution of — List of Members. 1918. 8vo. Crerar, The John, Library — Annual Report. 1917. 8vo. Croydon Public Libraries — Bi-Monthly Magazine. Readers' Index, No. 5. 8vo. 1918. .Editor's — Aeronautical Journal fcr July, 1918. 8vo. Athenffium for June-Aug. 1918. 4to. Author for June-Oct. 1918. 8vo Chemist and Druggist for July-Oct. 1918. 8vo. Church Gazttte for July-Oct. 1918. 8vo. Concrete for July-Oct. 1918. 8vo. Dyer and Calico Printer for July-Oct. 1918. 4to. Electrical Times for July-Oct 1918. 4to. Engineering for Julv-Oct. 1918. fol. Freight and Metal World, Vol. XXXIII. No. 1669, Aug. 1918. 4to. General Electric Review for July--Oct. 1918. 8vo. Horological Journal for Aug. -Oct. 1918. 8vo. Illuminating Engineer for May-July 1918. , 8vo. Journal of Physical Chemistry for June-Oct. 1918. 8vo. Junior Mechanics for July-Oct. 1918. 8vo. Law Journal for July-Oct. 1918. 8vo. London University Gazette for July-Sept. 1918. 4to. Model Engineer for July-Oct. 1918. 8vo. Musical Times for July-Oct. 1918. 8vo. Nature for July-Oct. 1918. 4 to. New Church Magazine for July-Oct. 1918. 8vo. Physical Review for July-Oct. 1918. 8vo. Science Abstracts for June-Aug. 1918. 8vo. Wireless World for July-Oct. 1918. 8vo. Zoophilist for Aug.-Oct. 1918. ^vo. Electrical Engineers, Institution o/— Journal, Vol. LVI. No. 276. 4to. 1918. Estudio de la Ciencias—Serie Matematico Fisica, Vol. I. No. 29, March 1917. 8vo. Faraday Socie^j/— Transactions, Vol. XIII. Part 3. 8vo. 1918. Firenze, Biblioteca Nazionale Centrale — Bollettino delle Pubblicazioni Italian!, No. 207, May-June, 1918. 8vo. 1918] General Monthly Meeting 353 Formosa, Government of — Flora of Formosa, Vol. VII. March 1918. 4to. Franklin Institute — Journal, June-Oct. 1918. 8vo. Geographical Society, Royal — Journal for July-Oct. 1918. 8vo. Supplement to No. 1, June 1918. 8vo. Geological Society of London — Abstracts of Proceedings. Quarterly Journal, Vol. LXXIII. 8vo. 1918. Geological Survey of Great Britain — Memoirs, 1917. 8vo. Glasgow, Royal Philosophical Society — Proceedings, Vol. XLVIII. 1917-18. 8vo. 1918. Hadfield, Sir Robert— AhstrRct of Co-ordination of Scientific Publications ■(pamphlet). 8vo. 1918. Helvetica Chimica Acta— Yol. I. 8vo. 1918. Horticultural Society, Royal — Journal, Vol. XLII. Parts 1-2, 1916 -17. 8vo. 1918. Imperial College of Science and Technology, London — Calendar, Session 1918-19. 8vo. 1918. Iron and Steel Institute— J onvnail, Vol. XCVII. No. 1. 1918. 8vo. Johns Hopkins University, Baltimore — University Circular, New Series, 1917, Nos. 293-300. 8vo. 1917 ; New Series, 1918, Nos. 301-304. 8vo. 1918. University Studies, Series 35, Nos. 2-3. 8vo. 1917; Series 36, Nos. 1-3. 8vo. 1918. Jordan, W. Leighton, Esq. {the Author) — The Squaring of the Circle (pamphlet). 8vo. 1918. Kansas University — Science Bulletin, Vol. X. No. 1, Jan. 1917. 8vo. Kyoto Imperial University — Memoirs of College of Science, Vol. III. No. 2, Feb. 1918. 8vo. Life-Boat Institution, Royal National — Journal for Aug. 1918, Vol. XXIII. No. 265. 8vo. 1918. London County Council — Gazette for July-Nov. 1918. 4to. London Society— J ouvnol for July-Sept. 1918. 8vo. London University — Gazette for July 1918. 4to. Manchester Literary and Philosophical Society — Memoirs and Proceedings, 1917-18, Vol. LXII. Part 1. 1918. 8vo. Manchester, School of Technology — Journal of the, Vol. IX. 4to. 1918. Mechanical Engineers, Institution of — Proceedings, Jan.-May 1918. 8vo. Mental Science— Journal of. Vol. LXIV. No. 266, July 1918. 8vo. Meteorological Office — Monthly Weather Reports for May-July 1918. 4to. Weekly Weather Pteports for April-Aug. 1918. 4to. Daily Readings for May-June 1918. 4to. Geophysical Journal — Daily Values for June- July 1918. Geophysical Memoirs, No. 12. 4to. 1918. Monthly Weather Report for Year 1917, Part 2. 4to. Weekly Weather Report, 1917, Appendix 2. 4to. Hourly Values from Autographic Records, Circular Nos. 28-29. 8vo. 1918. Thirteenth Annual Report, 1917-18. Svo. 1918. Metropolitan Asylums Board — Annual Report for Year 1917. 8vo. 1918. Ministry of Munitions — Munitions Inventions Department, Physical and Chemical Data of Nitrogen Compounds, April 1918. 4to. Monaco, Musee Oceanographiqu£ — Bulletin, Nos. 340-343. 8vo. 1918. Montenegrin Committee for National Union — Bulletin, Nos. 4-5, Sept. 1918. Svo. Myers, Lieut.-Col. Charles S. {the Author) — Present-Day Applications of Psychology. Svo. 1918. National Physical Laboratory — Report. for Year 1917-18. 4to. 1918. New Jersey, State o/^Department of Conservation and Development, Report for the Year ending Oct. 31, 1917. Svo. Neiv York Academy of Sciences — Annals, Vol. XXVII. pp. 215-248. Svo. Aug. 1917. 354 General Monthly Meeting [Nov. 4, New York, Society for Experimental Biology — Proceedings, Vol. XV. No. 8. 1918. 8vo. New Zealayid, High Cotmnissioyier for — Patent Office Journal, Vol. VII. Nos. 9-15. 1918. 4to. Census, Oct. 1916. 4to. Statistics for Year 1916, Vols. III.-IV. 4to. Official Year Book, 1917. 8vo. North British Association of Gas Managers — William Young Memorial Lecture. By John W. Cobb (pamphlet). 8vo. 1918. Numismatic Society, Royal — Numismatic Chronicle, Part I. 4th Series, Vol. XVIII. 1918. 8vo. Peru, Guerpo de Ingenieros de Minas — Boletins, Nos. 87, 89. 8vo. 1918. Pharmaceutical Society of Great Britain — Journals for July-Oct. 1918. 8vo. Philadelphia Academy of Natural /Sciences— Proceedings. Vol. LXIX. Parts 2, 4, April-Sept. 1917 ; Vol. LXX. Part 1, 1918. 8vo. Photographic Society, Royal — Journal, June 1918. 8vo. Physical Society of London — Proceedings, Vol. XXX. Parts 4-5. 1918. 8vo. Pusa, Agricultural Research Institute — Journal, Vol. XIII. Part 3, July 1918. 8vo. Real Academia de Ciencias — Revista de la Exactas, Fisicas y Naturales de Madrid, Tome XV. Nos. 10-12. 1917. 8vo ; Tome XVI. Nos. 1-5. 1917. 8vo. Rockfeller Foundation, The — Review, 1917. 8vo. Rockfeller Institute for Medical Research — Reprints, Vol. XXVIII. 8vo. 1918. Royal College of Surgeons of England — Calendar. 1918. 8vo. Royal Colonial Institute — United Empire, July-Sept. 1918. 8vo. Royal Engineers' Institute — Journal, Vol. XXVIII. No. 1, July 1918. 8vo ; Nos. 3-5, Sept.-Nov. 1918. 8yo. Royal Society of Arts — Journals for July-Oct. 1918. 8vo. Royal Society of Edinburgh — Transactions, Vol. LII. Part 1, Session 1917-18. 4to. 1918. Proceedings, 1917-18, Vol. XXXVIII. Part 2. 8vo. 1918. Royal Society of London— Proceedings, A, Vol. XCV. Nos. a665-a666, July 1918. 8vo ; B, Vol. XC. July 1918. 8vo. Royal Statistical Society — Journal, Vol. LXXXI. Part 3, May ; Part 4, July. 1918. 8vo. Royal United Service Institution — Journal of. Vol. LXIII. No. 451, Aug. 1918. 8vo. Scientific Societies, Conjoint Board of — Preliminary Report of Water Power Committee, July 1918. 8vo. Scottish Geographical Society, Royal- Scottish Geographical Magazine. Journal, Vol. XXXIV. No. l', July 1918. 8vo. Smithsonian Institutio7i — Miscellaneous Collections, Vol. LXIX. No. 6, June 1918. 8vo. Atmospheric Scattering of Light, Vol. LXIX. No. 3, May, 1918. 8vo. Annual Report of the Smithsonian Institution. Societa degli Spettroscopisti Italiani — Memorie, Serie 2, Vol. VII. Disp. 4-6. 1918. 4to. Society for Experimental Biology and Medicine — Proceedings, Vol. XV. No. 7, April 1918. 8vo. South Africa, Union o/— Department of Agriculture, Bulletin No. 2. 1918. 8vo. South African Association — Report for the Advancement of Science, Kimberley, 8vo. Spielmann, Sir Isidore — Germany's Impending Doom. (An Open Letter to Herr Maximilian Harden.) No. 2. 8vo. 1918. Stonyhurst College Observatory — Results of Meteorological, Magnetical and Seismological Observations, 1917. 1918] General Monthly Meeting 355 Tdhoku Imperial University, Sendai, Japan— Science Reports, 2nd Series, Vol. III. No. 2 : Vol. IV. No. 3. 1918. 4to. Tdhoku Mathematical Journal — June-Aug. 1918. Toronto, University of — Transactions of Royal Canadian Institute, 1st Series, Vol. VII. No. 1, July ; No. 26, Nov. 1917, Vol. XI. Part 2. 8vo. Studies, Nos. 3, 14-16, 58. 8vo. 1918 United States Department of Agriculture— Zounnal of Agricultural Research, May-Sept. 1918. 8vo. Index, Vol. XI. Experiment Station Record, Vol. XXVIII. Nos. 5-6, April-June ; Vol. XXXVIII. Nos. 1, 9 ; Vol. XXXIX. No. 1. 1918. 8vo. United States Department of Commerce — United States Coast and Geodetic Survev, 1915-16. 4to. 1918. Serial No. 61 : Special Publication, No. 42, for 1916. 4to. 1917. Serial No. 84, Magnetic Observations, Sitka, Alaska, 1915-16. 4to. 1918. Serial No. 86, Results of Observations made in Honolulu Magnetic Obser- vatory, 1915-16. 4to. 1918. Serial No. 88, Terrestrial Magnetism, Magnetic Observations for 1917. 8vo. 1918. United States Patent O^ce— Official Gazette, Vol. CCL. Nos. 1-4 ; Vol. CCLII. No. 1. 1918. 8vo. Upsala, r University d' V Observatoire MH^orologique — Bulletin Mensuel, Vol. XLIX. 1917. 4to. Uber die Gegenstrahlung der Atmosphare. By Anders Angstrom (Upsala). 1917. 4to. Arkiv. for Matematik, Astronomi och Fysik, Band 13, Nos. 7-8. 1918. 8vo. Upsala, Royal Society of — Nova Acta, Ser. 4, Vol. V. No. 1. 4to, 1918. Washington, National Acadetny of Sciences — Proceedings, Vol. IV. Nos. 7-8. July-Aug. 1918. 8vo. Western Society of Engineers — Journal, Vol. XXIII. No. 1, Jan. ; No. 2, Feb. 1918. 8vo. Zanichelli, Nicola — Casa Editrice, Bologna, I Fenomeni Elettro Atomic! sotto r Agione del Magnetismo. 8vo. 1918. GENERAL MONTHLY MEETING, Monday, December 2, 1918. Sir James Crichton-Browne, J. P. M.D. LL.D., F.R.S., Treasurer and Vice-President, in the Chair. The Secretary announced the decease of Sir Charles Norris Nicholson on November 29, 1918. The following Resolution of condolence was submitted to the Members and unanimously passed : — The Members of the Royal Institution of Great Britain desire to record their sense of the loss the Institution has sustained through the decease of Sir Charles Norris Nicholson, Bart., M.P., M.A. (Cantab.), LL.B., Vice-Chairman of the London War Pensions Committee. Sir Charles Norris Nicholson was a member of the Institution for twenty- eight years, and as a Manager took an active interest in the business affairs of the Institution, and the objects of the Foundation in the promotion and difiu- sion of Scientific knowledge. 8 56 General Monthly Meeting [Dec. 2, Resolved, That the Managers desire to express, on behalf of the Members of the Royal Institution, their most sincere sympathy with Lady Nicholson and the family in their bereavement. Report from the Managers, December 2, 1918 : — The Managers reported, That they had received a Present from Mrs. E dward Pollock oi the Portraits of her Father and Mother, the late Dr. and M rs. Warren de la Rue ; and a Donation of 26Z. 5s. from Dr. Dundas Grant to the Fund for the Promotion of Experimental Research at Low Temperatures. Resolved, That the special Thanks of the Members be returned to Mrs. E dward Pollock for her Present and to Dr. Dundas Grant for his Donation, The Chairman declared in the terms of the Bje-Laws, Chapter 4, Article 2, That there was a vacancy in the Office of Manager through the decease of Sir Charles Xorris Nicholson, Bart., M.P., and at the next General Meeting on February 3 the Vacancy will be filled in accordance with the said Bye-Law. The Peesexts received since the last Meeting were laid on the table, and the thanks of the Members returned for the same, viz. : — The Secretary of State for India — Bulletin of Agricultural Research Institute, Pusa, Nos. 81-82. 1918. Svo. Agricultural Journal of India, Vol. XIII. Part 4. 1918. Svo. Geological Survey of India, Records, Vol XLIX. Part 1. 1918. Svo. Accademia dei Lincei Reale, Roma — Atti, Serie Quinta : Rendiconti. Classe di Scienze Fisiche, Mathematiche e Naturali. Vol. XVIII. 1^ Semestre, Fasc. 1. 1918. Svo. American Cliemical Society— Ahatvacts for Oct. -Nov. 1918. Svo. Journal for Nov. 1918. Svo. Journal of Industrial and Engineering Chemistry for Oct.-Nov. 1918. 4to. American Geographical >Socie%— Geographical Review, Oct. 1918. Svo. Index to Bulletin, 1852-1915. Svo. 1918. American Philosophical Socie^?/— Proceedings, Vol. LVII. No. 5. 1918. Svo. American Red Cross — Trench Fever Report of Medical Research Committee, 1918. Svo. Auztralia, Commmwealth o/— Advisory Council of Science and Industry, Report for 1918. 4to. 1918. Agricultural Research in Australia, Bulletin No. 8. 1918. Svo. Bankers, Institute o/— Journal, Vol. XXXIX. Parts 8 and 9, October 1918. Svo. British Dental Association— Journal, Vol. XXXIX. Nos. 1-21. Svo. 1918. Cambridge Philosophical Society— Transactions, Vol. XXII. Nos. 12-14. 1918. 4to. Chemical Industry, Society o/— Journal, Oct.-Nov. Svo. 1918. Chemical Society— 3 onrnal for Oct.-Nov. 1918. Svo. Sdi^ors— Aeronautical Journal for Aug. 1918. Svo. Athenseum for Nov.-Dec. 1918. 4to. Author for Nov.-Dec. 1918. Svo. Chemist and Druggist for Nov.-Dec. 1918. Svo. Church Gazette for Nov.-Dec. 1918. Svo. Concrete for Nov.-Dec. 1918. Svo. Dyer and Calico Printer for Nov.-Dec. 1918. 4to. Electrical Times for Nov.-Dec. 1918. 4to. Engineering for Nov.-Dec. 191S. fol. 1918] General Monthly Meeting 357 Editors — continued. Freight and Metal World, Nov.-Dec. 1918. Ito. General Electric Review for Nov.- Dec. 1918. 8vo. Horological Journal for Nov.-Dec. 1918. 8vo. Illuminating Engineer for Nov.-Dec. 1918. 8vo. Journal of Physical Chemistry for Nov. 1918. 8vo. Junior Mechanics for Nov.-Dec. 1918. 8vo. Law Journal for Nov.-Dec. 1918. 8vo. London University Gazette for Nov.-Dec. 1918. 4to. Model Engineer for Nov.-Dec. 1918. 8vo. Musical Times for Nov.-Dec. 1918. 8vo. Nature for Nov.-Dec. 1918. 4to. New Church Magazine for Nov.-Dec. 1918. 8vo. Physical Review for Nov. 1918. 8vo. Science Abstracts for Sept. 1918. 8vo. Wireless World for Dec. 1918. 8vo. Zoophilist for Oct.-Nov. 1918. 8vo. Firenze, Biblioteca Nazionale Centrale — Bollettino delle Pubblicazioni Italian!, No. 208, July-Aug. 1918. 8vo. Fi-anklin Institute — Journal, Nov.-Dec. 1918. 8vo. Geographical Society, Royal — Journal for Nov. 1918. 8vo. Geological Society of London — Abstracts of Proceedings, No. 1028. 8vo. 1918. Hadfield, Sir Robert— The Occlusion of Gases by Metals. (Faraday Society Discussion), (pamphlet). 8vo. 1918. Harrison- Austin {Editor) — English Review, Nov. 1918. 8vo. Helvetica Cliimica Acta — Vol. I., Part 5. 8vo. 1918. Iron and Steel Institute — Carnegie Scholarship Memoirs, Vol. IX. Bvo. 1918. Leiden — Physical Lab. Communications from, Nos. 150-151. 8vo. 1918. Life-Boat Institution, Royal National— J ouvngd for Aug. 1918, Vol. XXIII. No. 266. 8vo. 1918. Linnean Society — Proceedings, Oct. 1918. 8vo. London County Council — Gazette for Nov.-Dec. 1918. 4to. London University — Gazette for Sept. 1918. Ito. Meteorological Office — Daily Readings for July-Sept. 1918. 4to. Geophysical Journal — Daily Values for Aug. -Nov. 1918. Monaco, Musee Oceanographiq;ue — Bulletin, Nos. 344-347. 8vo. 1918. Oxford University Press— The Periodical, Vol. VI. No. 98, Oct. 1918. 8vo. Pharmaceutical Society of Great Britaiji— Journal for Nov. 1918. 8vo. Photogra'phic Society, Royal — Journal, Nov. 1918. 8vo. Pusa, Agricultural Research Institute— 3 omnaA, Vol. XIII. Part 4. 1918. 8vo. Royal Engineers' Institute— J onvusil. Vol. XXVIII. No. 6. 8vo. 1918. Royal Irish .4ca(Ze?/ii/— Proceedings, Vol. XXXIV., A, Part 4 ; B, Parts 4-6; C, Parts 8-9. 1918. 8vo. Royal Society of Arts — Journal for Nov. 1918. 8vo. Roijal Society of Londo7i— Proceedings, A, Vol. XCV. No. 667, 1918. 8vo. ; Vol. XXXV. Part 1, 1918. 8vo. Saleehy, Dr. C. W. {the At^^/zo?-)— (Pamphlet.) Race Renewal : The Ideal of a Ministry of Health. 1918= 8vo. Sanitary histitute, iT'o?/aZ— Journal, Vol. XXXIX., No. 2. 1918. 8vo. Scottish Geographical Society, i?o?/aZ— Scottish Geographical Magazine. Journal, Vol. XXXIV. No. 11, Nov. 1918 8vo. Smithsonian Institution— Report of the U.S. National Museum, 1917. 8vo. 1918. South Africa, Union of -Official Year Book, 1910-16. 1917. 8vo. United States Department of Agriculture— J ouvn&\ of Agricultural Research, Oct. 1918. 8vo. Yorkshire Archseological Socie^— Journal, Vol. XXV. No. 9 ( . 8vo. 1918. YOL. XXII. (No. 112) 2 B 358 [IDIS WEEKLY EVENING MEETING, Friday, March 22, 1918. The Right Hon. Lord Raylbigh, O.M. P.C. D.C.L. F.R.8., Hon. Prof. Natural Philosophy, R.L, in the Chair. Professor Sir J. J. Thomson, O.M. LL.D. D.Sc. Pre.s.R.8., Professor of Natural Philosophy, R.L, Master of Trinity. Radiation from System of Electrons. [No Absteact.] [A footnote in the Philosophical Magazine, Vol. XLI. p. 510, "On the Structure of the Molecule and Chemical Combination,'' by Sir J. J. Thomson, states, " Many of the results in this paper were given by me in my Lectures at the Royal Institution between 1914 and 1919, but owing to the pressure of other duties 1 have not hitherto had leisure to prepare them for publication."] WEEKLY EVENING MEETING, Friday, May 10, 1918. The Hon. R. Clere Parsons, M.A. M.Inst.C.E.. Vice-President, in the Chair. Professor F. Gowland Hopkins. M.B. D.Sc. F.R.S. The Scientific Study of Human Nutrition. [No Abstract.] 191 mm. After the globe has drained for a day or two, there is not enough liquid left on the walls to keep the film sufficiently iuljricated to allow of such oscillations. The only liquid available is in the tiny channel — the Gibbs layer — round the periphery of the film. This channel is roughly triangular in section, with the base of the triangle on the glass walls, and the concave sides converging to the film which extends out beyond the apex of the triangle. In a very well-drained film the base of this triangle may not be more than O'l mm., so that the sectional area of the channel is about 3^^ Jooth of a sq. cm. The total liquid available round such a film 5G cm. diameter is, therefore, only about 1 cgm. It is obvious that 1918] on Studies on Liquid Films 361 Fig. 1. Fig. 2. 2 C 2 362 Professor Sir James Dewar [Jan. 18, 1918 long before such complete drainage as this is reached any movement of the film occurring over a relatively dry surface will quickly exhaust the liquid in the channel, and the film will be ruptured. However, when the proper precautions were taken, the displacements due to atmospheric variations did not amount to more than 1 or 2 mm. for weeks together. Until they become completely black very striking colour effects can be seen in these large horizontal films. They have of course only a small gradient of thickness, so that the bands of colour are drawn out into large areas. During this period convection in the films is most easily seen, because of the brilliant contrasts afforded by the moving portions. Should there be much fluctuation of tem- perature, the complete development to the black state may be arrested, the last part of the coloured area being kept in intermittent circulation for several days. Superfluous liquid draining down out- side the central tube will produce a similar result by becoming spread out on the black film surface as a coloured clot round the tube. When this clot grows sufficiently it will draw off slowly, and pass down the radius of greatest inclination of the film. It formed on one occasion an ellipse (1 cm. by 1^- cm.) which took 35 seconds to traverse the last one-fourth of its path. On approaching the periphery where the film curves up slightly into contact with the glass, the clot flattened out and curled into the most intricate con- volutions, finally sweeping round close to the edge, a writhing mass of coloured streaks, many of which became roving stars on the black film. The whole coloured area was finally drawn into the Gibbs ring, from which frequent escapes of small drops of liquid took place. A favourable condition for longevity is a quiet temperature rather below 10° C. Sudden alterations of 3° or 4° C. are most likely to ])urst the films by provoking too rapid convection therein, as is evidenced by very rapidly moving streams of silvery stars drawn from the Gibbs ring. The vibrations which occurred during the operation of the air compressors in the Laboratory did not affect the final stability of the black films. A stationary circular wave was produced having an amplitude of over 1 mm. vertically all round a circle midway between the central tube and the walls of the globe. This motion continued the whole time the machines were working, but the films always survived. Instead of having one large plane black film, a mesh-work of black films can be obtained completely filling the globe. To pro- duce this, the lower end of the blowing tube A (Fig. 1) is inserted slightly below the surface of the soap solution. The air current being regulated suita])ly to the diameter of the tube A, a steady succession of uniform bubbles is produced. The surface of the glass having previously been well moistened, the issuing bubbles conse- 364 Professor Sir James Dewar [Jan. 18, Fig. 3a. 1918] on Studies on Liquid Films 365 Fig. 36. Jan. 18, 1018] Studies on Liquid Films 367 qiiently encounter little resistance, and dovelope rapidly, linking up into a glittering lustrous froth which increases until the globe is full. Excess liquid drains away very rapidly, the black stage being reached in about an hour. The beauty of the mass can be seen properly only when a beam of liglit is flashed upon it in continually changing directions, the different inclinations of the internal plane films giving rise to a continuous series of brilliant scintillations (Fig. Sa). The same appearance is perhaps still more remarkable when the mesh- work is lit up by diffused light from rays thrown across the observer's line of vision (Fig. 36). A black background is used in both cases. The internal walls of the various cells being plane polygons, the pressure of the air in these cells is the same for all, and is regulated according to the curvature of the cell-walls on the outer boundary. As transference of the enmeshed air from the mass can take place only through the curved boundaries of the outer layer of bubbles, contraction of the mass from this cause is relatively slow. In one case it required a fort- night for the initial volume to be reduced to one half. To obtain the best result tlie blowing tube A should be withdrawn when the mesh-work has been completed, as it exerts some protecting power over the bubbles that closely surround it, thus causing an annular depression farther out, and tending to destroy the mass. Columns and Chains of Bubbles. For the purpose of studying bubble clusters and film complexes, instead of single bubbles and plane films, an arrangement of the nozzle was employed, by which it was possible to get a succession of bubbles of any required volume, linked together, in one operation. The apparatus employed is shown in Fig. 4. A is a stoppered reservoir of soap solution from which a capillary tube passes down the air-supply tube D, B, to about 1 cm. above a constriction K. After passing K the lower end of the air-supply tube is, for convenience, fitted by a ground joint to an enlarged nozzle C, securely held in position by the rubber cork E. The stopper A being opened at regulated intervals of time, a series -^ . . of drops falls on the constriction K, which are immediately Ijlown into films by the constant air current entering through the bulb D (protected as before by lightly packed glycerined cotton wool). Hence a series of bubbles is produced at the nozzle C, 368 Professor Sir James Dewar [Jan. l.s, which may have equal or different vohimes as desired, and may be further controlled so as to present themselves either as a vertical column or as a cluster. The shape of the cluster obtained depends on the dimensions of the nozzle, the speed of the air current, and the relation between the mass of the drop and the size of the constriction. If the drop be too large or the air current too slow, extra films result from the accumulation of superfluous liquid ; the same thing happens with an elongated constriction. On the other hand, too rapid a currant may simply spray the liquid over the interior of the nozzle. The cleanest working is obtained from a short neck blown out above and below in a spherical shape as shown in the figure at K. A succession of equal bubbles may either form a regular cluster on the mouth of the nozzle, or a vertical chain or column of spherical segments united by plane circular films. A cluster will usually be formed when the bubbles are less in diameter than the nozzle, and a chain or column when the bubbles are larger. For the manipulation of these complexes an air-tight, cubical, plate-glass chamber was made (Fig. 5), on a frame of aluminium alloy (edge, 50 cm.). The glass plate for the top was 1 cm. thick ; holes were cut in it for the rubber corks that held the nozzles and supported the movable glass rods which carried the different small pieces of apparatus used to catch and control the chains while being formed. For the manipulation of the longer columns the glass cylinder shown in Fig. 6 was used. It was 3 feet long and 6 inches in diameter; its ends made air-tight joints with two plates, the upper of which held the blowing nozzle, while the lower held a support ring. Suitable exit stopcock and soda-lime guard tube were also fitted. The support ring was sealed to the top of a vertical rod that could slide up and down in an air-tight joint in the bottom plate. The cylinder was fixed on a shelf in the middle of a massive wooden stand, and a hole was cut in the shelf to allow free movement to the sliding rod. When a to-and-fro motion was given to the support rod, tlie flexibility of the column was readily seen ; transverse waves appeared to pass up the Avhole length, each segment moving on the one adjacent as if attached by a very free universal joint. By drawing the rod down a considerable extension could l)e obtained; contrariwise by raising it a bulging or spiral formation would result. If this be carried further and the surface l)e sufiiciently moist, the column will sag out into contact with the glass walls and form a chain of oval segments. In a Avidcr vessel, however, the segments can in this way be linked up successively to form regular clusters. A beautiful exhibition of multiple scintillating coloured reflections is obtained when a beam from an arc lamp l)elow is directed up tlirough the column while the support rod is moved. An even more complete illumination is secured by using a white lined hood above, in which is hidden a 200-watt lamp, with two white wings of stiff 193'^] on Studies on Liquid Films 369 FiCx. 5. Fig. 6. 370 Professor Sir James Dewar [Jan. 18, card fixed one on each side of the central black stand. These side screens alone are snfficient for this purpose if the whole apparatus stands in a good light. A striking contrast is obtained when the column is drained to blackness and illuminated hj a beam from below, if an occasional drop of soap solution is allowed to trickle down through the nozzle. Before this is done very little is seen except the bright point reflections from the curved surfaces ; but, as the falling drops arrive in rapid succession at the planes between the adjacent segments, the thin circular channels flash up into sparkling silvery light from the internal reflections of the accumulated liquid. Fig. 7 gives some idea of the appearance. The following particulars show how some of the results were obtained : — (a) Nozzle, 3 cm. diameter; constriction, 1-15 mm. bore ; drop, 18 mgms. ; air current approximately 500 c.c. a minute ; drop interval, 5 seconds ; giving a volume of 42 c.c. for each segment. While they were being blown the free end was caught on one of the movable glass rings already mentioned, by means of which fifteen bubbles were steadily drawn out into a flexible catenary with its ends 13 cm. apart (Fig. 8). (h) Nozzle, 3*4 cm. diameter ; air current, 565 c.c. per minute ; drop interval, 7h seconds ; giving a volume of about 70 c.c. for each segment. A column of eight of these bubbles reached from the rim of the nozzle to the wet floor of the cube, where contact was made. The same nozzle could give a chain of nine bubbles of three times this volume. (c) Same nozzle ; air current, 305 c.c. per minute ; drop interval, 9 1 seconds ; giving a volume of about 48 c.c. for each segment. A column of ten of these bubbles was held on a fairly straight axis inclined at about 50° to the horizontal after they were drained free of excess liquid. Some of these chains are liable to break with excess liquid (Fig. 8). This can be largely obviated by using a percentage of hydrogen in the air current, provided an atmosphere of pure air is maintained in the glass cube. The buoyancy of the bubbles is thereby increased for a time sufficient to allow the column to be manipulated. When the chain has once been secured any further accumulation of liquid must be continually removed. For this purpose a fluted glass rod some 2 mm. thick and 3 or 4 cm. long was very effective. (It was made by drawing out a bundle of seven small glass rods in the blow-pipe, and was utilised by attachment to one of the movable bent glass rods passing through the top of the cubical box.) When very large bub])lc segments are required it is safer to interrupt the air current l)etween two adjacent segments, while a few extra drops of liquid are run in to remoisten the glass surfaces. In this way bubbles of over 1 litre were obtained on a nozzle 5 cm. 191» 85 •0884 5 3 2-92 •152 19-3 •552 Where n is the number of segments in the column ; / is its length in cms. ; iu is the attached weight in gms. ; e is the elongation in cms. ; X is the elongation per unit length of column ; and E is the corresponding value of Young's modulus. It will be noticed, on comparing the fourth set of these ob- servations with the first set, that (roughly) halving the weight and length reduced the elongation per unit length to one-fourth, as might be expected. For, a; = ^ and W = Ey, hence for the first case YOL. XXII. (Xo. 112) 2 E 392 Professor Sir James Dewar [Jan. 18, Black Development \n ^ HANGING Bubble c f V ^ « 10 D'^VS 12_ vJ ^TJ^^o^HuWle^ •5- 10- 20- 4 ^ Bctto-n cV Bm),U*-> (a) Black development .« BUBBLE POISED okRING p ^ 19 \^ 7p 7^ 3,t) 3^ ^ ^ ^0 191S] on Studies on Liquid Films 893 W/ = E^ ; for the second case, W /' - E' e', or AV / = 4 E' e'. . • . -^E'e = Ee. Now in the Table I. E' = -817, E = -Ss;}, or ap- proximately E' = 2 E, hence the last equation becomes S e' = e, or in terms of x, S x ^ I -=- x I, whence 4:x' = x. Gas Transference through Fil]vl Co3iplexes. Columns and clusters of bubbles generally reach the " black " stage with great rapidity by the action of the channels (Gibbs rings) of liquid where the segments join together. The black development of an ordinary hanging bubble is different from that of a similar bubble resting on a ring, because in the latter case the action of the Gibbs ring is to assist gravity in withdrawing liquid from the film and thus to accelerate the thinning process, w^hile in the former case the action of the Gibbs ring is against gravity, and thus retards the withdrawal of liquid from the film. The two curves in Fig. 29 show this difference very clearly : the black boundary on the poised bubble descending at an ever-increasing rate, as it approaches the Gibbs canal present on the support ring ; while in the hanging bubble the rate of fall continually decreases. (This is more notice- able when liquid is allowed to accumulate below while the thin black area extends downwards. In the al)sence of suitable drainage, the coloured zone then becomes continually thicker.) When however a bubble was provided with two Gibbs rings, one above and one below, the rate of fall of the black boundary was almost linear for the greater part of the time. This was arranged by attaching a small bubble under a large one, supported as usual from a nozzle above. The small bubble was kept steady by a smaller glass ring underneath. The nozzle was 8*3 cm. in diameter, and the size of the small attached bubble was adjusted so that the diameter of the Gibbs ring of contact between the two bubbles was about the same. The greater bubble was 40 cm. high between the equal Gibbs rings top and bottom, viz. where contact w^as made with the nozzle above, and the small bubble film below. The graph of " black fall " plotted with time was very nearly straight for 2^ days, by which time the black area had extended over three-fourths of the surface. After this it spread more slowly, and took another day and half to reach the lowest point. The form was therefore intermediate between curves {a) and {b) of Fig. 29. Xow, in the more complex clusters there are many channels all connected at various inclinations, therefore not only is any excess liquid quickly discharged, but the films themselves are quickly drained to the " black " state. This is the most favourable condition for the study of gas trans- ference, as the film is then at its minimum thickness. The resulting contraction has been measured in the case of straight columns and other complexes by photographs taken periodically. These afford 2 E 2 \u Professor Sir James Dewar [Jan. 18, Fig. 30. Fig. 31. 1!»18] on Studies on Liquid Films 395 direct evidence of greater rate of transference in the smaller bubbles ; for when records are taken of a column of unequal segments it is easily seen that the initial inequalities are accentuated as time goes on. Figs. 30 and 31 are reproductions from photographs of two small columns at intervals of nine and seven days respectively ; the volumes of the segments varied from 30 to 100 cm. Large l)lack volumes were more difficult to deal with on account of irregular oscillations ; their relatively small mass when black was insufficient to stabilise them against any local convection. For example, in the 200 litre globe already described a column was blown consisting of six segments, the upper five of which had each a capacity of Ij litres, while that of the lowest was 3 litres. In one day it became wholly black with the exception of a thick coloured area that extended up over 30 per cent, of the lowest bubble, the weight of which was sufficient to keep the whole hanging vertically, although some of the junction planes were slightly inclined. By the sixth day the colour had diminished to a zone 5 cm. wide. This reduced load could not keep the column straight, and some of the oscillations that occurred displaced the drop on the lowest bubble as much as 15 cm. from the vertical, while a vertical contraction of 15 mm. had accrued, followed in the next two days by a further contraction of Qh mm. The coloured zone was now a disc of 2 cm. diameter, and the column had become so curved that an unusually large oscillation caused the lowest bubble to touch the globe, with the result that only the two uppermost segments remained, the junction plane between them being inclined at 3o' to the horizontal. A light glass ring was therefore arranged below to keep the column stationary. It was sealed to a 3 mm. glass rod bent round in a bow, roughly to follow the contour of the globe, and then secured to a vertical glass rod that could slide air-tight in the rubber stopper at the neck. The contraction of the column due to the gas transference, however, went beyond the limits through which the glass rod could be raised. The segments therefore became thinner and more strained, until on the 89th day separation took place between the third and fourth. The glass ring thereupon relaxed a distance of 8 mm., the amount by which the glass bow had been strained by the pull of the black column. In some cases the various segments were measured daily by a cathetometer and horizontal sliding telescope. If I) is the diameter of a bubble segment at the equator, and d the diameter of the plane circular ends,' while h is the height, then the volume is given by y = 1'0472/i (0-4 D^ + i)"2 J)d + O'lbd^). When the segment is unstrained, d ^ D - 0*268A, so that y = l-0472A(0-75 D- - O'lSO J)h + O'OU-); only D and h need therefore be measured. 896 Professor Sir James Dewar [Jan. 18, verv well with the dimensions These relations were found to agree of seojments of known volume. , , . , .1 . r The area of the curved surface through which the gas transfer- ence takes place (there being practically no loss through the plane (1) (2) (3) (4) (5) (6) (1) (2) (3) (5) (6) Fig. 32. Fig. 33. Fig. 34. ends) is given for a buhl)le whose centre of curvature is not in the axis of revolution by S = "' \)h -('l''' - 27rU^= 8-289 1)/ 8 V 8 / V - ()-29.")//" It must be noted that an'uncontracted bubble segment has been assumed. Tliis, however, was no longer the case when it became necessarv to fix the column at both ends (to a nozzle above and a glass ring ])elow). As the contraction proceeded therefore the total leno-th did not alter, so that h remained practically the same 1918] on Studies on Liquid Films 397 throughout; but as the segments shrank D and d continually diminished. Three illustrations of this are shown in Figs. 32-34. Thej are taken from a column of six bubbles in the 200 litre globe already descriljed. The four top bubbles were of equal volume, while the two lowest were half the volume of the others. The third segment being between two similar ones remained symmetrical to the end, and thus gave more reliable results. The contraction finally resulted m the column pulHng apart l)etween the fifth and sixth bubbles on the 64th day. The upper five were thus left free, but the oscillations were so persistent that only a blurred photograph was possible ; this was, however, sufficient to give some measures of the free segments for comparison with those obtained when strained. Fig. 32 was taken at the stare, Fig. 33 on the 16th day, and Fig. 34 on the 64th day before partition took place. The volumes and surfaces for the third segment selected for cal- culation were as follows (Table II.) :— Black Six-BuhhU Chain. Table II. Dimensions of Segment (3). Time 1 (Fig. 32) 16 (Fig. 33) 64. (Fig. 34) Days Volume 1133 1029 543 c.c.'s Curved Surface 360 350-5 258 (cm.) Table III. Air Transfer through Segment (3). Volume 1000 750 805 650 288 14 0049 600 279 c.c. s Curved Surface 346 (cm.)2 ( c.c.'s Eate of Transfer < per 7-6 0-022 0-76 11-3 0-037 16 through whole surface 1 day 0-059 per (cm.)- Volume Contraction ... 1-51 2-15 2-67 per cent, per day 398 Professor Sir James Dewar [Jan. 18, When the vahies were plotted with time, contraction cnrves were obtained for both vohime and surface. By taking tangents to the vokime and time curve at successive intervals of time, the corre- sponding rates of gas transference — - were deduced. Fio. 85. Fig. 30. The third segment thus gave the values shown in Table III. for air transference through the black lilm composed of 3^ per cent ammonium oleate and 33 per cent glycerin. Three sets of these columns in the 200 litre globe were tried. The first was the largest in volume, and took 101 days to pull apart. Figs. 35 and 3G show the appearances at start and tinisb, the total 191s] on Studies on Liquid Films 399 leng'th meantime had Ijeeii reduced from 5:> * ii to 50 * 9 cm. ; after this the free bubbles remained on the nozzle a fmther 53 days. They were then replaced by the second set already described, which took 64 days before it divided. The third set which followed was more uniform, consisting of one segment, top and bottom, each of whose volumes was half a htre, while the four in the middle con- tained one litre each. This set parted in 40 days. Very good black columns were also obtained in the long glass cylinder (Fig. 6). With this it was possible to prevent undue straining of the segments by carefully raising the support ring when necessary. The cylinder was long enough to get in ten segments, each of over 250 c.c. A thin thread of stranded cellulose (artificial silk) was sometimes fixed both at the nozzle and support ring to lie along the outer contour of the column from top to bottom. This not only stabilised the column while being blown, but accelerated the drainage and black development, because any excess liquid in the Gibbs ring channels of the junction planes was quickly drawn into the capillary canals of the silk. The result was that the black stage was complete in one day, and there was entire absence of any deformation from superfluous liquid remaining in the junction rings. One set took 47 days before the shrinkage caused the segments to part, the support ring not having been raised. The ratio of length to breadth of the equal segments two days before this occurred was 1*5 :1, as compared to 1*17 :1 in a similar coloured column of like dimensions, but without any cellulose thread, and dragged apart by loading (see Fig. 28). The segment volumes of another set diminished during the first fortnight from about 270 c.c. to 225 c.c, and the curved surfaces from 145 to 120 scjuare centimetres. The calculated rates of air transference obtained from the contraction curves, are given in Table lY. ; the solution used contained 5 per cent ammonium oleate and 50 per cent glycerin. Table IA'. Volume 265 250 139-5 3-62 0-026 1-45 235 136 5-24 c.c.'s Curved Surface 143 (cm.)^ j c.c.'s Rate of Transfer < per 1 day 1-83 through whole surface 0-013 0-039 2-23 per (cm.)- Volume Contraction . . . 0-69 per cent per day 400 Professor Sir James Dewar [Jan. 18, Much higher values were given by a black column of five equal segments, initially 161 c.c, very completely drained by two cellulose strands on opposite sides of the bubble contours. No glass ring support was employed, so that the column contracted freely without the segments being strained out of their normal curvature. In four days the volume diminished 30 per cent. The mean rate of air transference being nearly 11 c.c. per day when each segment had a volume of approximately 125 c.c. The corresponding value of the curved surface was about (cm.)-, so that the loss through unit area was 0 ' 14 c.c. per day. The solution used for this contained 1 per cent ammonium oleate ta 10 per cent, of glycerin. GrAS Diffusion Through Black Films. The rate at which gases diffuse through liquid films was found to be very much greater than the slow escape caused by the small excess-pressure by which bubbles are distended. The latter only becomes appreciable some days after the black stage is reached ; but if a thick coloured air bubble has a small percentage of hydrogen blown into it, a contraction takes place in a few minutes ; or, con- versely, an expansion is quickly produced by circulating some hydrogen in the closed vessel in which the bubble is hanging. In the same way when a plane film Avas formed across a cylindrical vessel containing only air and some soap solution, and hydrogen was then circulated in the space between the film and the neck, a steady movement of the film towards the neck at once began ; the hydrogen passed through to the enclosed space Ijeyond the film more quickly than the contained air diffused out. The reverse process was easily carried out by first filling the bottle with pure hydrogen, and expanding the film as before. A current of clean air was then cir- culated on the same side of the film as before ; the resulting move- ment of the film was now away from the neck, because the volume enclosed beyond the film lost hydrogen more quickly than air could diffuse in. When oxygen was used instead of air the motion was more rapid. When these experiments were made after the black stage was reached, the diffusion was sufficiently rapid to cause a large distortion of the plane film, due to partial adhesion round the periphery of the film, although the glass walls had previously been well moistened. For the laboratory measures of the relative diffusion rates of various gases, an 8 litre bottle, 19 cm. in diameter, was calibrated, and the movements of the film (which would thus have an area of some 300 cm.-) were noted for successive small time intervals. The stopper was fitted with inlet and outlet tubes, of which the former was long enough to reach the bottom, and could also slide easily in an airtight fitting. The film was thereby started by pushing the inlet tube down 1918] on Studies on Liquid Films 401 into a small quantity of soap solution in the bottle, and then witl) drawing it gradually as the gas current expanded it to the desired position. The tube was then pulled just through the film, the current nearly slnit off, and the whole left to settle until tlie l)lack zone had developed sufficiently in the film. The gas to be circulated was then connected and turned on, and the movements of the film noted. The end of the outlet tube was kept within a cm. of the film surface to maintain a thorough circulation. With hydrogen in the vessel, and when the film was half black and half silvery (next in thickness to black), and air was circulating at 130 c.c. per minute, the volume enclosed by the film decreased at a fairly uniform rate of 1 litre in 20 minntes. After this the movement became slower as the percentage of hydrogen diminished in the space beyond the film. Finally, 5*70 litres of hydrogen originally present were found to be replaced l)y 1 • 40 litre of air. In another experi- ment, with the film almost completely black, G • 28 litres of hydrogen diffused out and were replaced by I'So litre of air. The maximum rate of diffusion coidd not be realised in this wide vessel because of the film distortion that was produced when the rate of circulation was increased. To over- come this a vessel only 8*5 cm. in diameter was used (Fig. 37), in which the ordinary stopcock was replaced by a two-way cock A, while an inlet and outlet fitting was fixed in the rubber stopper. The outlet tube as before could slide easily in its air- tight neck. The vessel was filled with hydrogen coming in through A and leaving at B. The film was obtained (after first moistening the walls of the vessel) by tilting a drop of the soap solution into the neck at A. The gas entering there 402 Professor Sir James Dewar [Jan. IS, at once formed a film and pushed it along to the desired position. A was then closed and the film left to become black. Meanwhile a small current of hydrogen was continued through B and C to prevent any subsequent disturbance of the film, such as by an alteration of temperature. co^ \ ir\r\r\ SFiLM ,n HYOBOOtlN N^XYCEN CirJCULATtD ^ 900 \ X^ \ VOLUMt UNDER FILM / 800 / \ Z.0.YOE. ^^ / AlYDBOCEN CIRCUUVTED 700 / O 5 10 TIME 15 MlNUTLo 20 Hydrogen- Oxygen Diffusion r„«ouc„ Black Film Fig. Before starting the air or oxygen current through B and C the film was lubricated by a slow complete revolution of the vessel, whereby the small amount of liquid inside flowed all round the walls. This caused some diminution of the black area, which was measured and allowed for. Dui'ing the suljsequent diffusion the 1918] on Studies on Liquid Films 403 sliding tube was adjusted so that its open end was kept within a centimetre of the moving film. Small measured samples of the mixed gases behind the films were withdrawn at intervals for analysis through the two-way cock A. The maximum rate of diffusion of hydrogen above that of air was found to be 42 c.c. per hour per cm-. When oxygen was used instead of air the value obtained was 50 c.c. of hydrogen per hour per cm.- greater than the oxygen going the other way ; and 1145 c.c. of hydrogen passed out, while 632 c.c. of oxygen went in. When the reverse process was tried 1173 c.c. of hydrogen went in through the black film, while 635 c.c. of oxygen diffused out. The two operations involved the passage of the film 7 cm. along the cylinder in the first case, and the same back again for the reversal. Fig 38 gives the graphs of the movement of the film, and shows tbe variation of the enclosed volume, with the time. The rate of relative diffusion at any time is given by the slope of the tangent to volume- time curves. This was found to decrease as the proportion of oxygen under the film increased. The contraction of bubbles in air when blown up with from lU per cent, to 30 per cent, of hydrogen was measured in order to deduce the diffusion rates through coloured films. A much lower value was obtained : thus a bubble coloured steely blue to pale amber and containing 16 per cent, of hydrogen showed a rate of contrac- tion of approximately f c.c. per hour per cm^. Measures were also made with half bubbles blown on the roof of a glass chamber in which a proportion of hydrogen was circulated ; and also by com- paring the contractions of similar bubbles when hanging from a nozzle and resting on a ring. This last was done to correct for the distortion of figure produced by the buoyancy of the contained hvdrosfen. Hydrogen Bubbles Blowx under Several at3i0spheres. Bubbles that have thinned to blackness contract at an ever- increasing rate by the continual transference of the enclosed gas through the envelope. It was mentioned in last year's Discourse that this contraction is greatly retarded when the bubbles are formed in an enclosure in which the pressure has been raised, the excess- pressure distending the bubble becoming then of relatively smaller proportion to the total pressure. Further experiments have shown that a black bubble in hydrogen under G'3 atmospheres pressure took 100 days for its diameter to contract from 7 "7 to 4' 0 cm., whereas only 7 to 10 days is needed for the same contraction to take place in a similar bubble at atmospheric pressure. When air was used instead of hydrogen the difference was equally marked ; thus 404 Professor Sir James Dewar [Jan. 18, an 8 cm. bul)l)le in a vessel charged to 7 atmospheres took 4 months to diminish 1 cm. in diameter, the same contraction at atmospheric pressure taking only about 14 days. Suitable vessels for these measurements are afforded by the strong glass bottles used to hold sulphurous acid. A screwed brass collar was cemented to the neck, and to this a brass T -piece was secured by a gas-tight union. The glass nozzle for supporting the bubble was cemented into the vertical arm of the T-tube, and sealed to a thick glass bulb above bent over horizontally to hold some soap solution. The gas used was admitted by the valved horizontal arm of the T-piece, a hole being made at this level into the inner glass tube to give access through the nozzle, which had a diameter of about 1 cm. (Fig. 39). Just within its lower end a constriction was formed. The apparatus was tested and found tight under 10 atmospheres pressure. The pressure was first ad- justed to about 6 atmospheres, and a drop of soap solution was decanted into the constriction ; on admitting more gas a bubble was expanded on the nozzle and the pressure thereby raised to 6J atmospheres. The black stage then developed very much as usual, and the gas transference was determined by periodic mea- surements of the contraction. Table V. gives the rate of transference obtained in hydro- gen at C)^ atmospheres compared with the values at 1 atmosphere. The numbers given are calculated for diameters of 4, 6 and 8 cm. The second column gives the internal excess pressure P of the soap bubl)le (in mm. of water) measured at atmospheric pressure. The proportion F of this to the total pressure in the bu])])le vessel is shown in the third column (in units of 10"") both for 1 atmosphere and G-^ atmospheres. The ol)served rates of gas transference K, are similarly shown in the fourth column. Fig. 39. 1918] on Studies on Liquid Films Table V. 405 Diameter P mni.'s H2O 1' X lo-« E c.c.'s cm.'s (a) 1 atm. (b) 6-5 atm. (a) 1 atm. (ft) 6-5 atm. 4 0-330 32-16 1 4-80 j 0-22 0-0825 6 0-220 21-44 3-20 0-14 0-041 S 0-166 16-08 2-40 0-10 — Thus it may be said that the longevity is increased in the propor- tion of the numbers given in the last two columns, in this case, approximately as the square roots of the relative pressures under which the bubbles were blown. For experimental assistance I have to thank ^Y. J. Gi'een, B.Sc, and for reading the proofs and checking the calculations, I am indebted to J. D. H. Dickson, M.A., Senior Fellow of Peterhouse College, Cambridge. [J. D.] LONDON : PRINTED BY WILLIAM CLOWES AND SONS, LIMITED, GREAT WINDMILL STREET, W.I, AND DUKE STREET, STAMFORD STREET, S.E I ^ PROCEEDINGS OP THE Royal Institution of Great Britain Vol. XXII. -Part III. No. 113 Jan. 17. Jan. 24. Jan. 31 Feb. 3. Feb. 7. Feb. 14. Feb. 21. Feb. 28. March 3. March 7. March 14 March 21 March 28 April 4. April 7. April 11. Mayl. May 2. May 5. May 9. May 16. May 28. May 30. June 2. June 6. July 7. Nov. 3. Dec. 1. 1919. Sir James Dewab — Liquid Oxygen in Warfare Lieut. -Coii. Andeew Balfour — One Side of War H. H. Turner — Giant Suns General Meeting J. G. Adami — Medical Research in relationship to the War ... Cargill G. Knott — Earthquake Waves and the Interior of the Earth A. T. Hare — Clock Escapements ... Sir Oliver Lodge — Ether and Matter General Meeting H. C. H. Carpenter— The Hardening of Steel Arthur KEiTH^The Organ of Hearing from a New Point of View W. W. Watts — Fossil Landscapes Sir John H. A. Macdonald — The Air Road Frederic Harrison— History of the City of Constantinople... General Meeting Sir J. J. Thomson — Piezo Electricity and its Applications . . . Annual Meeting John W. Nicholson — Energy Distribution in Spectra General Meeting ,. Sir George Macartney — Chinese Turkistan : Past and Present Sidney F. Harmer — Subantarctic Whales and Whaling Sib Alexander C. Mackenzie— Hubert Hastings Parry : His Work and Place among British Composers ... Sir John Rose Bradford— A " Filter-passing " Virus in Certain Diseases ... General Meeting ... -Atomic Sir Ernest Rutherford— lisions with Light Atoms General Meeting ... General Meeting ... General Meeting ... Index to Volume XXII Projectiles and their Col- PAGB 591 407 411 421 424 / 440 446 454 478 481 508 590 512 515 517 590 521 522 530 534 537 542 %0 563 567 577 581 587 621 LONDON ALBEMARLE STREET, PICCADILLY 1922 1019] One Side of War 4o; WEEKLY EVENING MEETING, Friday, January 24, 11)10. The Hox. Richard Clere -Parsons, M.A. M.Inst. C.E., Vice-President, in the Chair. Colonel Andrew Balfour, C.B. C.M.G. M.D. R.A.M.C. One Side of War. Colonel Balfour commenced his discourse with the following- remarks : — " It is my purpose this afternoon to give you a demonstration on what I have called ' One Side of War.' It is the medical side concerning which I will speak, that being the only aspect of which I have any special knowledge, and, even so, such knowledge is confined to certain sections. " Now the Medical Side of War, like all Gaul, is divided into three parts : the strictly medical, embracing hospital administration, clinical and ambulance work of all kinds ; the sanitary, or, as it should be called, the preventive part ; and last, but by no means least, the scientific, which is also largely of a preventive nature. " In addition to France and Flanders, of which I saw very little, I have been privileged to visit all the important tropical and sub-tropical theatres of war. As a member of the Medical Advisory Committee I went in 1915 to Egypt, Mudros and Gallipoli. In 1916 I was with that Committee once more in Eygpt and also in Macedonia, Malta, India, Mesopotamia and Persia. Leaving Mesopotamia early in 1917 I returned to India, thence to England, and thereafter accompanied Major-General Pike to South and East Africa, my itinerary in the latter comprising Portuguese Territory, the late German Colony, British East Africa and Uganda. From Uganda I travelled via the Sudan to Egypt, and finally, at General Allenby's kind invitation, proceeded to Palestine to see the anti-mosquito operations there. " As it is my intention to show you something of all three divisions of the Medical Side of War in most of the countries I have mentioned, it is obvious that the pooner I turn from these notes to the screen Vol. XXII. (No. 113) 2 f 408 Colonel Andrew Balfour [Jan. 24, the better, a resolution which I do not doubt you will heartily approve. '' Thanks to Mr. Wellcome, who placed the resources of his Bureau wholly at the disposal of the War Office, I was able to take a large number of instructive photographs which will form the subject of our demonstration. I need hardly say that, in the time at my disposal, I can only touch the fringe of my subject ; but I will lay some stress on the sanitary and scientific aspects of the various campaigns, for these are the departments of work which least catch the public eye, and, I fear, possess the least interest, not only to the man in the street, but even to some of those on whom responsibility rests, or has rested." He commenced his lantern demonstration with pictures taken in Macedonia, showing the type of tented stationary hospital ; the hilly roads which it had been necessary to make, and which in some cases had been built by the staffs of field ambulances ; improvised quarters constructed of biscuit boxes ; methods of transporting sick and wounded ; various devices for collecting and purifying water, for ablution ; oamp cooking ; transport of food ; and more especially the measures taken for dealing with malaria, both by quinine administra- tion and by attacking breeding-places of the anfqjiieles mosquito. He passed next to the island of Lemnos, where various pictures taken at Mudros were shown indicating methods of disinfection in the field, ornamentation of hospitals and other matters of sanitary interest. Proceeding to the Gallipoli Peninsula a series of slides was exhibited showing the conditions under which the men had to live in the trenches at Anzac, and the terrible strain thrown upon them in connection with the transport of water from the Ijeach to the summits of the hills w^here the trenches were situated. Somewhat similar views, taken at Cape Heiles, were also shown, and then the scene was changed to Egypt, where a hospital ship was seen in Alexandria harbour. Thereafter the various sanitary features of the campaign, both in Egypt and Palestine, were fully illustrated, of special interest being the views indicating anti-mosquito operations in the Jordan Valley and the arrangements made for a])lution on the western Egyptian front. The transport of sick and wounded men by camel was also demonstrated, as were the precautions taken to prevent the spread of small-pox by the men of the Egyptian Labour and Camel Corps. Attention was drawn to the elaborate arrangements for scientific work both in Egypt and Palestine, and pictures were shown of well-equipped bacteriological and protozoological mobile labora- tories. The lecturer then transported his audience to German East Africa. The photographs taken in this area showed hoAv different the medical and sanitary conditions are in a country of bush and dense forest from those obtaining in a bare and hilly land such as 1919] on One Side of War 409 Macedonia or a desert country like much of Egypt. The work of hospitals and hospital ships was illustrated and explained, and a tribute paid to the nurses, who here laboured under very trying: conditions. The difficulties connected with the transport of sick and wounded and the methods taken to overcome them by the employment of the machilla or hammock were shown on the screen. Before proceeding to the last of the war areas described, i.e. Mesopotamia, a striking photograph of the British Military Cemetery at Bloemfontein was exhibited, showing the long lines of graves of those who died, chiefly of enteric fever, during the Boer "War before preventive inoculation had become a general measure. Colonel Balfour stated that happily on no front could such a sight be witnessed in this war, and then exhibited a fcAv photographs demon- strating the method of preparation of anti-typhoid vaccine employed at the Kasauli Institute in India. Large supplies of anti-typhoid and anti-cholera vaccines were sent from this Central Eesearch Institute for the use of the troops in Mesopotamia. Turning to the latter area, the lecturer explained the difference existing between the southern portion of Mesopotamia and that through which the troops had to pass on their way to Baghdad. Special attention was paid to the measures taken for dealing with the ubiquitous fly, which was a veritable curse in Mesopotomia, and pictures were shown ranging from Nasariyeh on the Euphrates to Ahwaz on the Karun River and from Basra to El Sinn. Illustrations were given of cases of scurvy, and occasion was taken to point out that our lack of accurate scientific knowledge had resulted in a waste of much money in the provision of lime juice. Recent work had shown that lemon juice is four times as efficacious as lime juice in the treatment of scorbutic conditions. The last picture shown was one of the Tree of the Knowledge of Good and Evil growing at Kurnah, the reputed Garden of Eden. This is the Mesopotamia wild plum, and apparently to it should be attributed all the troubles and disasters of the war. The lecturer, however, remarked that he could not realise how anyone could imperil his immortal soul for the sake of a Mesopotamian wild plum. He concluded his address in the following terms : — " Through it all, ladies and gentlemen, through all the toil and tribulation, the sickness and the stench, the filth and flies, muddles and mistakes, waste and wounds, heat, thirst, discomfort and death, the British soldier has been splendid. So, in most cases, have also been the Indian and the African under our leadership. " I think I have shown you enough to prove that the Side of War which we have considered is a hard and difficult one. It has, believe me, its heroes and victims, quite apart from those who gain the laurel crown or the wreath of cypress in the battle zone itself. "But who, man or woman, would not strive and labour for men 2 F 2 410 Colonel Andrew Balfour on One Side of War [Jan. 24, of the type of the average British soldier — a type I can best explain by a short, but what is even better, a true story. " A young lad lay seriously ill in one of the great hospitals of Malta. The consulting physician approached his bed and said to him, ' Well, my boy, how are you to-day ? ' " The patient replied as he had always replied w^hen asked this •question throughout many weary days. ' In the pink,' he answered feebly, and, having so answered, he lay back quietly and died." [A. B.] 1919] Giant Suns 411 WEEKLY EVENING MEETING, Friday, January 31, 1919. The Hon. Richard Clere Parsons, M.A. M.Inst.C.E., Vice-President, in the Chair. Professor H. H. Turner, D.Sc. D.C.L. F.R.S. ■ F.R.A.S. Giant Suns. We have all been fascinated by Giants, from the times we read of Jack the Giant Killer in our childhood to those more recent when we read of the exploits of Lient. Warneford and his successors in their fights with the Giant Zeppelins. I make no apology for shortening my title a little from what astronomers might expect. I might have chosen " Giant and Dwarf Stars,'' but stars are suns, as we shall see presently, and though I shall include " dwarf " suns, the real dwarfs of science are the tiny atoms at the other end of the scale of investigation — or rather, the electrons into which they have been broken up. How shall we gauge the size of a star to see whether it is a giant ? We must know two things : first of all, the apparent size of its disc, and secondly, its distance. In the old days it was thought that the size of the sun could be estimated from one of these only — from the size of the disc. Lucretius,""' following Epicurus, believed that the sun was a small body. He arrived at this conclusion by neglecting entirely the consideration of the distance and judging by the appearance to our senses. Now, without attempting to decide whether the sun is the size of a soup-plate, or of a threepenny-bit, or what is the size that it seems to be, we may remark that it seems to be about the same size as the moon, and that by Lucretius' principle the sun and moon ought to be of the same actual size. However, we now know that the sun is 400 times bigger than the moon, because its distance is 400 times greater. We have measured the distance of the sun and found it to be nearly 100 million miles, and we have measured that of the moon and found it to be nearly a \ million ; and since the discs appear of about the same * " Nee nimio solis major rota nee minor ardor Esse potest, nostris quam sensibus esse videtur." Lucret., De Nat. Bev., v. 564-5. 41: Professor H. H. Turner [Jan. 8L angular size (viz. about y^otti part of the distance in each case), we know that the sun must be about a milhon miles in diameter and the moon only about 2500 miles, using round numbers throughout for simplicity. Thus the sun is' a veritable giant compared with the moon, in spite of the similar apparent size of the discs ; but this we discover only when we have measured the distances. The sun and moon present to us large discs which we can study in detail, and the study of the disc of the sun by means of the spectroheliograph has had new triumphs which, owing to the War, have not yet been seen in this room, so that I may be pardoned for exhibiting one. (Mount Wilson spectroheliogram shown.) But when we come to the stars there is no disc. If one seems to see discs for these objects, the appearance comes through the imper- fections of the telescope. Hence it would seem to be superfluous to inquire about their distance. When Mark Twain had been roughly handled at Niagara Falls, and the doctor reported that only sixteen of his wounds were mortal, he said " he did not care about the others." In the same way we might argue that since the stars have no appreciable discs we need not care about their distances. That, however, was not the attitude of men of science. Tney went to work to measure their distances, and though the difficulties were heart-breaking they were attacked and overcome. Here is a table showing a sensible fraction of the life-work of an eminent Scotsman, Sir David Gill, observing at the Cape of Good Hope. It Gill's Parallaxes of Bright Stars star Parallax Distance in Light- Years Sirius 0-37 9 Canopus 0-00 ? Rigel 0-00 9 a Centauri 0-75 4 a Eridani 0-04 80 3 Centauri 0-03 100 a Crucis 0-05 64 Spica 0-00 9 a Pise. Austr. 0-13 25 3 Crucis 000 9 includes the famous a Centauri, the first star to have its distance measured at all, which again was by a Scotsman, Henderson, also observing at tlie Cape of Good Hope. Sir David Gill was accustomed to describe the difficulties of determining that distance by saying that it was like trying to 1919] on Giant Suns 418 measure the size of a threepenny-bit two miles off ; and we remember his delight when his chairman on one occasion asked, " Who but a Scotsman would care about a threepenny-bit two miles away ? " But you will see that this star is the nearest and therefore easiest of all ; while some even of these brightest stars gave no result even to a patient Scotsman. Those that are measurable show that they are so far off that light takes years to come to us from them — from some four years ; from others hundreds of years ; from those with no measurable result, thousands of years at least. Thus we began to obtain a little knowledge of the distance of the stars. The method used for these measurements was the usual method of Parallax, which we may illustrate by two searchlights trained on the same Zeppelin. Knowing their distance apart and the angles at which they are sending their beams of light, those working tlie apparatus can draw the triangle to scale and thus tell the height of the Zeppelin. Xow replace the two searchlights by two telescopes- — one on one side of the earth's orljit round the sun, and the other on the other side ; they cannot be there simultaneously, but the star will wait six months for us to move round or even longer. The angle at the Zeppelin becomes however woefully small as we suppose it to mount to the stars. It is twice the angle which seems to separate earth and sun as seen from the Zeppelin, and it is this angle which is re- presented by the diameter of " a threepenny-bit two miles away." From the distance of the nearest star the sun and earth might appear as a close double star, of which there are many examples in the heavens, though our little earth would probably be too faint to be seen, even from the nearest star-spectator. There would be no such difficulty in seeing the sun, but since his diameter is only y^o^^ P^i'l^ of the distance between earth and sun, which has itself shrunk to almost imperceptible dimensions, it is easy to realise that the disc of the sun would have disappeared completely, as does any disc of the stars to us, even with our largest telescopes. Since we have imagined ourselves to mount far upwards to a Centauri, whence the sun and earth would represent a close double star, let us retain the conception a moment longer in order to note a useful fact. Watching long enough we should see the pair moving across the heavens^ while at the same time the earth would revolve round its mighty companion. The sun would proceed therefore very much more steadily than the earth. The sun's path is nearly straight, while the earth takes a wavy path, or more correctly a corkscrew path. If the masses of the two bodies were more nearly equal, the two paths would be more nearly alike, and both wavy. By observing such movements (for we can observe the movements of stars) we infer whether one component of a double star is more massive than the other or whether they are nearly equal ; and it is found that there is never any very great disparity in mass between 414 Professor H. H. Turner [Jan. 31, the compoiients. Their masses are closely similar, like those of pebbles on a beach. But this tells us nothing about the sizes of the minute discs. Have I gone too far peihaps in saying there is no disc visible in any star ? Nebulae do show discs, and though they are nebulae and not stars they may become stars. Here is a beautiful picture of the "Owl" nebula, taken with the Mount Wilson five-foot. It shows a beautiful circular disc with a star in the centre. Com- paring Lord Rosse's drawing of it made with his wonderful six-foot reflector, we see the much greater perfection of the photograph ; but this is chiefly due not to the inferiority of Lord Rosse's instrument, which was a marvel of engineering skill, but to the greater efficiency of photography compared witli the eye. The new secrets w^rested from the stars have chiefly come, not from the increase in size of telescopes, but from the new appliances attached to them, such as the photographic plate, the spectroscope, and by this time many others. The lines in the spectra of stars tell us what the stars are made of, how they may be classified accordingly, how fast they are moving, how bright they really are (this is an amazing recent discovery), and by inference how far away, and may yet have other surprises in store. For the moment we are chiefly concerned with the classificafion. The Harvard system gives us a number of classes denoted bv the capital letters O" B A F G K M R N. The fact that the order is not quite the same as that of the alphabet represents a revision of early ideas, chiefly due to the gradual accumulation of intermediate types, which make a nearly continuous series. Now a series of stars in order is probably a representation of growth ; just as the growth of trees may be illustrated by selecting various stages from the same wood, an illustration originally given by Sir W. Herschel. But we have seen a tree grow, and we know independently that it grows up from the acorn through the sapling to the giant oak ; while we have not had time to see a star grow and were thus in ignorance whether the changes are from B towards M or from M towards B, though by this time we have an immense number classified. The classification has been largely the work of an American lady, Miss Cannon. I am told that there is a man who can deftly straighten rifle barrels — he gives a glance along the barrel, a tap with a hammer, and lo ! it is straight. His value is recognised at some £15 a week. Miss Cannon has the same deftness with spectra — but I fear that (to judge from the report of the Board of Visitors of Harvard Observatory) her great skill is not so appro- priately rewarded. Now it is obviously important to find out, if we can, which is the direction of a star's growth, and we seemed to have an important clue when the spectral classification was connected with the tempera- ture of a star, or rather its surface temperature, which is all we can get at. The outside is the coolest, just as the edges of a plate of porridge are the coolest, as most of us have learnt by early and rather 1919] on Giant Suns 415- painful experience. And yet the outside of a star is hot enouojh. The temperature is again estimated from the spectrum, though this time not from the hues but from the relative intensities of the ends, and the 0 B A end is undoubtedly hotter than the other. We may give as iUustrations 15,000° for B, 5,000^ for G, and 2,500° for M. Does this settle the matter r We know that there is a general tendency for all bodies to cool which points to the direction C B — M N as the order of events ; but it w^as also known that under the stress of gravitation a star might rise in temperature, in which case the growth might be the other way. Still the former alternative commended itself more generally ; and when Prof. W. W. Campbell found that the velocities of stars (also determined with the spectro- scope) were smaller for type B than for type M, the facts were interpreted to mean that a star moved more quickly with advancing age (^because M stars were older than B). The idea that the life of a star was spent in passage down the series 0 B — M was indeed pretty firmly established at the time when the revolution came. The revolution began with the advent of a young American research student, Mr. H. N. Russell, to Cambridge in lOOd-6. It is to the credit of Mr. A. R. Hinks that he made so much of this brilliant young student, setting him on the way to determine tue distances of a number of stars by photography with the instruments which he (Mr. Hinks) has spent much time and labour in perfecting. This was the first element in his success. The next was that on his return to America he got from the Harvard Observator} — that store- house of astronomical facts— the spectral types of his stars ; and combining these with the measures of distance (which told him the intrinsic brightness or luminosities of the stars) he found that stars of the same spectral type M fell into two distinct groups separated by an interval. There w'ere very bright stars, now called Giants, and there were very faint ones, now called Dwarfs, but none of inter- mediate stature. The same was true in minor degree for stars of other types, but as the B end of the series w^as approached the gap gradually dis- appeared much in the way that the gap between the legs of a step- ladder gradually lessens as we approach the top. Indeed Russell's diagram of his results is very like a step-ladder, the top representing the B stars followed by A, F, G, K, M, in descending order, and the gap between the two legs of the ladder representing the difference in luminosity, as the intrinsic brightness of a star has come to be called. Russell brought this diagram with him when he came to attend the meeting of the Solar Union at Bonn in 1913. It is sad to remember the occasion, for the most friendly relations seemed to have been permanently established between the various nations assembled. We remember with especial regret the trip on a great steamer on the Rhine which ended the meeting, and, alas ! was the end also of our hopes of a permanent friendliness, for before the 416 Professor H. H. Turner [Jan. 81, year had passed the G-reat War had shattered them all. It was on his return from Germany through England that Russell showed us his step-ladder diagram at the Royal Astronomical Society, and expounded his views on the evolution of a star, which were that its life began at the foot of the upright leg, the ascent of which signified that the star was growing continually hotter and changing its spectral type meantime from M upwards towards B, that at B the increase of temperature was arrested and after a time cooling began carrying the star down the inclined leg of the ladder through changes in the reverse order. The only weak spot in the evidence arose from the small number of observations. To determine the actual or intrinsic brightness of a star we must know its distance, and there are not many stars of which the distance can be easily measured, and though Russell had himself increased the number, the total was still not large. To get further evidence he had recourse to indirect estimates of distance, especially those of clusters of stars. We have lately become more and more aware of the association of stars in clusters represented by their common movement, somewhat in the way that the movements of a flock of birds migrating from one place to another are associated. If we may accept this evidence, and if we can determine the distance of any one star in the cluster, the distances of the others can be inferred. In Russell's skilful hands this evidence was collated and found to strengthen his conclusions. Let us pause here for a moment to reflect on the inherent proba- bility of the suggestion. Is it not after all much more likely that a star first rises in temperature and then falls rather than that it should be permanently either rising and falling ? Now that the idea has been put forward, and that there seems to be not only good evidence of this change in the sky, but, as we shall presently see, also good theoretical reason for it, we wonder why tlie idea was not the most natural one to adopt from the first. But curiously enough it was not the one adopted by astronomers, with the notable excep- tion of Sir Xorman Lockyer, who made the same suggestion as Russell's (though on different grounds) many years before. May I give a crude illustration from our ordinary life of the mistake that was made by many of us ? It is as though we had taken the amount of hair as an indication of the age of a man. In very early life the amount of hair is small, it increases Avith age up to a certain point, but then it begins to decrease until a very old man often has as little hair as a new-born baby. We could give Shakespeare's Seven Ages of Man according to the amount of hair in the same diagrammatic form as Russell's step-ladder, beginning with the baby at the foot of the upright leg, ascending to the man in middle life with maximum hair (corresponding to the maximum temperature), and placing the greater ages down the inclined leg till we arrive again at a bald pate. Shakespeare reminds us with his phrase about the voice " turning again toward a childish treble " that not only the hair l)ut 1919] on Giant Suns 417 the voice goes through changes which show a reversal after middle life. We were practically confusing the baby stars with the old man stars until Russell called our attention to the fact ; and now it seems quite easy to make the distinction. But there was some hesitation before the new views were accepted at all, chiefly on account of the lack of sufficient measures of distance, which left room for doubt. Recently the evidence has been reinforced in a remarkable way by a totally new and unexpected method for inferring the distances of stars, due to Mr. W. S. Adams, of the Mount Wilson Observatory in California. His discovery is that if we have two stars, one of which is very bright intrinsically and the other faint, but both of the same spectral type, we can find two lines of the spectra which have different relative intensities : let us call them A and B. In the bright star A is more intense than B, in the faint star B will be more intense than A. Now observe that this difference will persist however far we may remove the stars from us. By altering the distances we may make the brighter star appear the fainter, but we can pierce its disguise by noting simply that the line xV in the spectra is the more intense, so that if the star appears faint we see at once that this must be due to its greater distance. In fact we can infer the distance from the relative intensities of the lines A and B, so that Adams has really given us a new method of inferring dis- tances. The new method has the further advantage of requiring far less labour than the old method of parallax ; in fact, when once the spectrum has been photographed the further labour required is quite small, so that by this time Adams has been able to give us the luminosity of hundreds of new stars, and by this overwhelming evidence confirms Russell's results derived from merely a few. In reply to a request he has sent me specially for this lecture the following table of results, and I am sure you will appreciate his kind- ness. [In the lecture the results were represented diagrammatically ; here Adams's actual figares are reproduced on the next page. To see the " step-ladder " hold the table sideways, so that the column of absolute magnitudes is at the bottom. The upright leg is then represented by the two rules across the page. It will be seen that the majority of intrinsically luminous stars are contained between these lines. The sloping leg is easily seen from the lie of the figures. That there are very few faint stars of class M does not mean that there are few in the heavens, but that they are the most difficult to observe from their faintness.] In addition to this confirmation by new observations we have had an independent confirmation by the brilliant theoretical work of Professor Eddington, who has attacked the problem of the life of a star mathematically. He supposed a mass of gas first of all to be simply under the action of its own gravity. It will consequently contract, and owing to the contraction will rise in temperature ; but Professor Eddington soon found that this simple hypothesis would 418 Professor H. H. Turner [Jan. y>l, W. S. Adams's Results up to November 8, 1918. Abs. Mag. Mc to Md ■ K4 to Kg G9 to K3 F9 to Gg A7 to Fg - 2-8 1 ... 1 - 2-3 1 ... ... 2 - 1-8 1 ... '2 3 - 1-3 1 "4 1 3 2 - 0-8 15 34 12 7 5 - 0-3 11 36 33 33 7 + 0-2 35 11 70 44 3 + 0-7 13 72 34 12 + 1-2 6 ... 22 21 13 + 1-7 1 12 8 5 + 2-2 7 2 18 + 2-7 3 5 15 + 3-2 4 2 17 + 3-7 ... 1 7 20 + 4-2 3 11 35 4- 4-7 3 28 22 + 5-2 "1 4 21 18 + 5-7 0 8 26 ... + 6-2 3 38 32 ... + 6-7 11 15 4 ... + 7 2 13 10 ... ... + 7-7 5 3 ... + 8-2 8 ... ... + 8-7 13 ... ... + 9-2 4 ... + 9-7 '3 2 ... + 10-2 4 ... ... + 10-7 3 ... + 11-2 3 ... ... + 11-7 ... ... ... + 12-2 ... ... + 12-7 ... + 13-2 1 145 ... Total ... 99 321 290 193 not answer — it led him to impossible results. Clearly something else besides g:ravitv must be at work, and he was driven to the further hypothesis that the radiation-pressure inside the star played an important part in its history. Radiation-pressure (or if we like to call it so, li