mtd ee a Rapes ON Lr mie: oe y « Ries , ek tina’) iL ‘ Nas Bat tre r eh We Ae ie > Pcs aa ae Pras Cae BRITISH ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE REPORT of the EIGHTY - EIGHTH MEETING CARDIFF-—1920 AUGUST 24—28 LONDON JOHN MURRAY, ALBEMARLE STREET OFFICE OF THE ASSOCIATION BURLINGTON HOUSE, LONDON, W.1 1920 3 ait Ye eee OQWMITHIM HTHOIM - YEH. 6so1--AMGAAD SsEs T2EUOUA- = _ TaaATe s.ARAMSE th “—— CONTENTS. PAGE MIRRORS AND! COUNUI, PO20—2U = GR Ne. is Meets ledivchaes vooulsuven teens iv OFFICERS OF SECTIONS, CARDIFF, 1920...........0.0. ccc cccceeseeeeseceeeees euneee vi OFKICERS OF CONFERENCE OF DELEGATES .....c.cc0scccccccscccccescscceceusecs Vii AnnuaL MEETINGS: PiLacEsS AND DatEs, PRESIDENTS, ATTENDANCES, Receipts, SUMS PAID’ ON ACCOUNT OF GRANTS FOR SCIENTIFIC IPEEPOSES: (18d L020 \reeeactenscnch cate deaass siceebocadeieatienessecseecorsasegnes Vili REPORT OF THE COUNCIL TO THE GENERAL CoMMITTEE (1919-20)......... xii CreneEan MEETINGS HA CARDIFE 50's) 5 spidecsn cbuicess 0 s0cceaasesictiacssoveceslsteute xvii PUBLIC, LROTURESMAT CARDIBE 8 oe eee ade ties eceosaseeeass xvii GENERAL TREASURER’S ACCOUNT (1919-20)...........c..cccsceereecenceceeeensecs xviii RESEARCH CoMMITTEES' (1920-21) 200... eee llcceeectucebenssaecceasqene XX RESOLUTIONS AND RECOMMENDATIONS (CARDIFF MEETING) ............0..008 XXVi CATRDATIUND PSS CUARE, Bee MINES oa van RSS aod Le TO PERE RRA ol XXX Sep AI CONE RAT, WBE TUNG rer crnicge cb ccbacs sence ape rmarenascaidaane wanes XXxi ADDRESS BY THE PRESIDENT, Pror. W. A. HeRpMAN, C.B.E., F.R.S.... 1 SECTIONAL PRESIDENTS’ ADDRESSES: A,—(Pror. A. S. EppINGTon, FIR.S.) soe sdapet edad s cc eeen aes aa ceel CaM 34 [can ap! Ms 3 Hrn' 604 ead Op oc 9 AR Seabee aetna ah 50 lie Helvetia AH MCLs.) scene tveressvaaes. sviaxstarscer recsies 61 D.—(Pror. J. STANLEY GARDINER, WURIS.)..........cccccsesseseeeeeeece 87 HBS Gliey VGA AINE MN On ect as sna nsesenssvesavenenerssaneneeders 98 F.—(Dr. J. H. Cuapnam, C.B.E.).........00+ Rion Sarde ax dake obo du dac bene ae 114 Gi (PRO; ©. B. SENKIN, CBSE) scscascccacagsiress o-0ccercseseucuchocss 125 Et ——(EROK., KARL PEARSON) ES. eae. oo. scc0cess sveniesoneebegeene 135 Meant Ae EA OH UE lel vrs) ales aioe cieitnclne's aalehie's er aleie se nslaivelvc semis asc anied 152 Ke (Miss Hi. Ri. SAUNDERS)\-sas: visaqeasaaaocscocrseeneccecnedudvelwcces 169 (Sik ROBERTI BrAtR poMrAn)s ..5.36 15 Sk Wades ket lash eccsevcnes 191 Rie (Ronen, (We kenbor, ©.B.Bi, BORG). tcc. ecsecntgee anctansias 200 REPORTS ON THE STATE OF SCIENCE, &C.....c.ccccecscscccsceee seseeveceecesceees 215 IERANGACTIONS" OFT THE "SECTIONS wc .w th scuttle dee wereateoas sodeeveedaevarwecniges 351 REFERENCES TO PUBLICATION OF COMMUNICATIONS TO THE SECTIONS ... 380 EVENING DISCOURSES .........cccseceesseeeee EL : IIT t airs, cceeiteterawnsaoneses 384 CORRESPONDING SOCIETIES COMMITTEE...........0.0sesccceecestssscceccescnssecees 391 REE Eire paper eM PEM scat C oly Une ivnniag's a's aussi acecenenspieelne ncaa vss SGM aNecle ne wsigeresine 436 APPENDIX—THIRD REPORT ON COLLOID CHEMISTRY! ........ccccseeeeeeee ees 1-154 1 Printed and published separately by H.M. Stationery Office. OFFICERS AND COUNCIL, 1920-21. PATRON. HIS MAJESTY THE KING, PRESIDENT. Professor W. A. HerpMAN, C.B.E., D.Sc., LL.D., F.R.S. PRESIDENT ELECT. Sir T. EDWARD THorPE, O.B., D.Sc., Sc.D., LL.D., F.R.S. VICE-PRESIDENTS FOR THE CARDIFF MEETING. The Right Hon. the Lorp MAyor or CARDIFF | The Right Hon. Lorp TrepEGAR, D.L. (Councillor G. F. Forspike, J.P.). E. H. GRIFFITHS, D,Sc., F.R.S. The Most Noble the Marquis or BUTE. Sir J. Herbert Oory, Bart., M.P. The Right Hon. the EARL oF PLyMourTH, P.O. | Principal A. H. Trow, D.Sc. (Principal of Uni- (Lord-Lieutenant of the County of Glamorgan). versity College of S. Wales and Monmouthshire ; Major-Gen. the Right Hon. LorD TREOWEN, O.B., President, Cardiff Naturalists’ Society). C.M.G. (Lord-Lieutenant of the County of | J. Dyer Lewis (President, South Wales Institute Monmouth). of Engineers). The Right Hon. LorD ABERDARE, D.L. R. O. SANDERSON (President, Oardiff Chamber of The Right Hon. Lonp PoNTYpRIDD, D.L, Commerce). VICE-PRESIDENTS ELECT FOR THE EDINBURGH MEETING. The Right Hon, the LorD Provost OF EDIN- Sir ALFRED EwinG, F.R.S. (Principal of the BURGH. University of Edinburgh). The Right Hon. R. Munro, P.O. (H.M. Secretary The Right Hon. Viscount LINLITHGOW, of State for Scotland). Sir E. SHARPEY SCHAFER, F.R.S. The Right Hon. Lorp CLYDE (Lord Justice Sir Roperr Usner (Convener of Midlothian General), County Council). Sir IsAAc BAYLEY BALFounR, F.R.S. GENERAL TREASURER. E, H. Grirrirus, Se.D., D.Sc., LL.D., F.R.S, GENERAL SECRETARIES. Professor H. H. TURNER, D.Sc., D.O.L., F.R.S. | Professor J. L. Myris, O.B.E., M.A., F.S.A. ASSISTANT SECRETARY. 0. J. R. HowartH, O.B.E., M.A., Burlington House, London, W. 1. ORDINARY MEMBERS OF THE COUNCIL. ARMSTRONG, Dr. E. F., F.R.S. HADFIELD, Sir R., Bart., F.R.S. | Morris, Sir D., K.0.M.G. BARCROFT, J., F.R.S. HALL, Sir DANIEL, K.O.B., F.R.S. | Pops, Sir W. J., F.R.S. Bonk, Professor W. A., F.R.S. | HARMER, Sir S. F., K.B.E., F.R.S. | Rivers, Dr. W. H. R., F.R.S. Drxey, Dr. F. A., F.R.S. JEANS, J. H., F.R.S. SAUNDERS, Miss E. R. Dyson, Sir F. W., F.R.S. KEITH, Professor A., F.R.S. Scott, Professor W. R. Fowl Ler, Professor A., F.R.S. KE TIRE, Sir J. Scorr. STRAHAN, Sir AUBREY, F.R.S. GARDINER, Professor J. SrANLEY,| KIRKALDY, Professor A. W. WHITAKER, W., F.R.S. F.R.S. MITCHELL, Dr. P. CHALMERS, WoopwarD, Dr. A. SMITH, GrReGoRY, Sir R. A. F.RB.S. F.R.S. LOCAL TREASURER FOR THE MEETING AT EDINBURGH. Councillor T. B. WHITSON. LOCAL SECRETARIES FOR THE MEETING AT EDINBURGH. ANDREW GRIERSON, Town Clerk of EDINBURGH. | Professor J, H, ASHWORTH, F.R.S, 4 io — Te OFFICERS AND COUNCIL. Vv EX-OFFICIO MEMBERS OF THE COUNCIL. The Trustees, past Presidents of the Association, the President and Vice-Presidents for the year, the President and Vice-Presidents Elect, past and present General Treasurers and General Secretaries, past Assistant General Secretaries, and the Local Treasurers and Local Secretaries for the ensuing Annual Meeting. TRUSTEES (PERMANENT). Major P. A. MacManon, D.Sce., LL.D., F.R.S., F.R.A.S. | Sir ARTHUR EVANS, M.A.,LL.D.,F.R.S., F.S.A. Hon, Sir CHARLES PARSONS, K.C.B., M.A., LL.D., D.Sc., F.R.S. PAST PRESIDENTS OF THE ASSOCIATION. Sir A. Geikie, K.0.B.,0.M., F.R.S, |Sir Francis Darwin, F.R.S. | Professor W. Bateson, F.R.S. Sir James Dewar, F.R.S. Sir J.J. Thomson,O.M., Pres.R.S. Sir Arthur Schuster, F.R.S, Arthur J. Balfour, O.M., F.R.S. Professor T. G. Bonney, F.R.S, Sir Arthur Evans, F.R.S. Sir E. Ray Lankester, K.O.B., | Sir E. Sharpey Schafer, F.R.S. |Hon. Sir C. Parsons, K.O.B., F.R.S. Sir Oliver Lodge, F.R.8. \ ERS. PAST GENERAL OFFICERS OF THE ASSOCIATION. Professor T. G. Bonney, F.R.S. Dr. D. H. Scott, F.R.S. Major P. A, MacMahon, F.R.S. Sir E. Sharpey Schafer, F.R.S. Dr. J. G@. Garson. Professor W. A. Herdman, C.B.E., F.R.S. HON. AUDITORS. Sir EDWARD BRABROOK, C.B. l Professor A. BOWLEY, OFFICERS OF SECTIONS AT THE CARDIFF MEETING, 1920. A.—MATHEMATICAL AND PHYSICAL SCIENCE. President.— Prof. A. 8. Epp1neton, M.Sc., F.R.S. Vice-Presidents.—_K. H. Grirritus, Se.D., D.Se., LL.D., F.R.S.; Prof. G. H. Harpy, M.A., F.R.S.; Prof. A. L. Senpy, M.A. Secretaries —_W. Maxower, M.A., D.Sc. (Recorder); H. R. Hagst; J. Jackson ; A. O. Ranxrne, D.Se.; *Capt. J. H. SHaxsy, B.Sc. B,—CHEMISTRY. President.—C. T. Hrycock, M.A., F.R.S. Vice- Presidents.—Prof. P. Partiturrs Brepson, D.Sc.; Prof. C. M. THompson, D.Sc. Secretaries—Prof. C. H. Dzscu, D.Se., Ph.D. (Recorder); H. F. Cowarp, D.Se. (Acting); *Prof. E. P. Penman, D.Se. C.—GEOLOGY. President.—F. A. BaTuEer, D.Sc., F.R.S. Vice-Presidents.—J. W. Evans, LL.B., D.Sc., F.R.S.; H. K. Jorpan, D.Sc.; Principal T. Franxurn Srpry, D.Se. Secretaries—A. R. DwerrynHouse, T.D., D.Se. (Recorder); W. T. Gorpon, D.Se.; G. Hickiine, D.Sc.; *Prof. A. HusErt Cox, Ph.D. D.—ZOOLOGY. President.—Prof. J. STANLEY GARDINER, M.A., F.R.S. Vice-Presidents—I’. A. Dixry, M.A., M.D., F.R.S.; Prof. G. Greson ; Prof. E. S. Goopricu, M.A., F.R.S.; W. Evans Hoyuez, D.Sce.; CRESSWELL SHBARER, D.Sc., F.R.S. Secretaries.—Prof. J. H. Asuwortu, D.Sc., F.R.S. (Recorder) ; F. Batrour Browns, M.A.; R. D. Lauriz, M.A.; *H. Epgar Satmon. E.—GHOGRAPHY. President.—J. McFaruang, M.A. Vice-Presidents.—Rev. W. J. Barton, M.A.; H. O. Becxit, M.A.; J. Bouton, M.A.; G. G. CutsHotm, M.A.; D. Lururer THomas. Secretaries.—_R. N. Rupmosse Brown, D.Se. (Recorder); C. B. Fawcett; *A. E. L. Hupson. F.—ECONOMICS. President.—J. H. Cuapuam, C.B.E., Litt.D. Vice-Presidents.—Sir Hucu Berut,- Bart., C.B., D.L.; Sir E. Brasrook, C.B.; Prof. A. W. Kirkanpy, M.A., M.Com. Secretaries—C. R. Fay, M.A. (Recorder); J. Cunntson; Miss L. GRIER; *Prof. W. J. Roperts, M.A. * Local Sectional Secretaries. OFFICERS OF sECTIONS, 1920. vii G.—ENGINEERING. President.—Prof. C. F. Jenkin, C.B.E., M.A. Vice-Presidents.—J. Dyer Lewis; Davip E. Ropers. Secretaries.—Prof. G. W. O. Howr, D.Se. (Recorder); Prof. F. C. Lea, D.Se.; Prof. W. H. Watkinson ; *Prof. F. Bacon, M.A. H.—ANTHROPOLOGY. President.—Prof. Karu Pearson, M.A., F.R.S. Vice- Presidents.—Prof. D. Hrrsurn, C.M.G., M.D.; Epwarp Owen, M.A.; H. J. E. PEAKE. Secretaries.—E. N. Fauuaizz, B.A. (Recorder); Rey. E. O. JAMES; F. C. Surupsat, M.D.; *Prof. H. J. Finurs, D.Sc. I.—PHY SIOLOGY. President.—J. Barcrort, B.Sc., F.R.S. Vice-Presidents.—S. Moncxton Copeman, F.R.S; Prof. J. B. Haycorart, M.D., B.Sc.; T. Lewis, M.D., D.Se., F.R.S.; C. S. Myers, D.S8e., F.R.S. Secretaries.—Prof. H. E. Roar, M.D., D.Se. (Recorder); C. L. Burr; e Lovatr Evans, D.Se.; Prof. P. T. Herrine, M.D.; *T. H. BuRLEND, pats K.— BOTANY. President.—Miss E. R. SAUNDERS. Vice-Presidents.—Prof. R. CHopat; Sir Danret Morris, K.C.M.G., D.Se., D.C.L., LL.D.; Prof. R. W. Paruips; Prof. A. C. SEwarD, D.Sc., F.R.S.; Principal A. H. Trow, D.Sc.; Prof. J. Luoyp WILLIAMs. Secretaries-—Miss E. N. Mites Tuomas, D.Sc. (Recorder); TP. T. Brooks; W. E. Hitry; *Miss KE. VAcHELL. L.—EDUCATION. President.—Sir Ropert Buarr, M.A. Vice-Presidents.—Principal J. C. Maxwetn Garnett, M.A.; Sir R. A. Gregory; Miss E. P. Hueues, LL.D.; Sir Naprer Suaw, M.A,, Se.D., F.R.S.; Herpert M. THompson. Secretaries.—D. BernipGs, M.A. (Recorder); C. E. Browns, B.Sc. E. H. Trrep, Ph.D.; *Stanney H. Warxins, M.A., Ph.D. M.—AGRICULTURE. President.—Prof. F. W. Krenz, C.B.E., Se.D., F.R.S. Vice-Presidents.—C. Crowruer, Ph.D.; C. Bryner Jones, C.B.E. Secretaries—A. Lauprer, D.Sc. (Recorder); C. G. T. Morison ; H. G. Toornton; *H. ALEXANDER. CONFERENCE OF DELEGATES OF CORRESPONDING SOCIETIES. President.—T. SHrerPparD, M.Sc., F.G.S. Vice-President.—T. W. SOWERBUTTS. Secretary.—W. Mark WEBB. * Local Sectional Secretaries Vili ATTENDANCES AND RECEIPTS. Table showing the Attendances and Receipts . . Old Life | New Life. Date of Meeting Where held Presidents MentuersulaMembers 1831, Sept. 27...... Viscount Milton, D.O.L., F.R.S. ...... _ _ 1832, June 19....., ..| The Rev. W. Buckland, F.R.S. _ _— 1833, June 25...... ..| The Rev. A. Sedgwick, F.R.S. _ _ 1834, Sept. 8 ...... ..| Sir T. M. Brisbane, D.O.L., F. R. 3.) _ _ 1835, Aug. 10...... ..| The Rev. Provost Lloyd,LL.D., F.R. s. —_ — 1836, Aug. 22....., .| The Marquis of Lansdowne, F.R.S.... — — 1837, Sept. 11...... The Earl of Burlington, F.R.S.......... = 7 1838, Aug. 10...... Newcastle-on-Tyne,..| The Duke of Northumberland, F.RS,) = — 1839, Aug. 26 ...... Birmingham .,,...... The Rey. W. Vernon Harcourt, F.R.S.) = _ | 1840, Sept.17...... ..| The Marquis of Breadalbane, F.R.S. = _ 1841, July 20 ...... ..| The Rev. W. Whewell, F.R.S. ......... 169 65 1842, June 23,,, .| The Lord Francis Egerton, F.GS. ... 303 169 1843, Aug. 17.. The Earl of Rosse, F.R.S. ............... 109 28 1844, Sept. 26 ..| The Rev. G. Peacock, D.D., F.RB.S. 226 150 1845, Junel9....., .| Sir John F. W. Herschel, Bart. » FR. 8. 313 36 1846, Sept. 10...... Sir Roderick I. Murchison ‘Bart. sF.R.S. 241 10 1847, June 23 ...... .| Sir Robert H. Inglis, Bart., FERS. 314 18 1848, Aug.9 ...... 3 TheMarquis ofNorthampton, Pres.R.S. 149 3 1849, Sept. 12...... Birmingham .,....... The Rey. T. R. Robinson, D.D., F.R.8. 227 12 1850, July 21 ...... Edinburgh ,.,........ Sir David Brewster, K.H., F. RS....... 235 9 1851, July 2..,,......| Ipswich ..... | G. B. Airy, Astronomer Royal, F.R.S. 172 8 1852, Sept.1 ...... IBOLEASG oii ccsselececsess Lieut.-General Sabine, F.R.S. .., 164 10 1853, Sept.3 Han 3.5 5;, ...| William Hopkins, F.RS.......... 141 13 1854, Sept. 20...... Liverpool ., ...| The Earl of Harrowby, F.R.S. 238 23 1855, Sept. 12......| Glasgow..... ..| The Duke of Argyll, F.R.S. ; 194 33 1856, Aug.6 ......) Cheltenham ..| Prof. 0. G. B. Daubeny, M.D., F.R.S.... 182 14 1857, Aug. 26 .| Dublin .. ..| The Rey. H. Lloyd, D.D., F.R.S. 236 15 1858, Sept. 22...... Leeds ........ ..| Richard Owen, M.D., D. 0. Ea, FBS... 222 42 1859, Sept.14...... Aberdeen ., ..| H.R.H. The Prince Consort maanenannaa 184 27 1860, June 27 ...... Oxford ..... ..| The Lord Wrottesley, M.A., F.R.S. . 286 21 1861, Sept.4 0... Manchester . ..| William Fairbairn, LL.D., F.B.S....... 321 113 1862, Oct.1 ...... Cambridge ............ The Rey. Professor Willis,M.A.,F.R.S. 239 15 1863, Aug. 26...... Newcastle-on-Tyne...| SirWilliam G. Armstrong,O.B., F.R.S. 203 36 1864, Sept.13...... Bath 4. ccd fe die cased Sir Oharles Lyell, Bart., M.A., F.R.S. 287 40 1865, Sepr6 oe: Birmingham., ..| Prof, J. Phillips, M.A., LL.D. a "ERS. 292 44 1866, Aug. 22"... Nottingham, ":| William R. Grove, Q.0., F.R.S 207 31 1867, Sept.4 ...... Dundee ...,..... ..| The Duke of Buccleuch, K.0.B 167 25 1868, Aug. 19 Norwich Dr. Joseph D. Hooker, BRS. was 196 18 1869, Aug. 18 Exeter . .| Prof. G. G. Stokes, D. 0. L., F.R.S....... 204 21 1870, Sept. 14,.,...) Liverpool .. ..| Prof. T. H. Huxley, LL. D. ERS. ... 314 39 A871, Aug. 2) 5.) Edinbur gh Ey .| Prof. Sir W. Thomson, LL. D. ay ERS s. 246 28 1872, Aug.14...... Brighton ..... ..| Dr. W. B. Carpenter, F.R.S. 245 36 1873, Sept.17...... Bradford ., ..| Prof. A. W. Williamson, F.R.S. 212 27 1874, Aug. 19 |... Belfast ... ""| Prof. J. Tyndall, LL.D., F.R. 162 13 1875, Aug. 25...... Bristol .., .| Sir John Hawkshaw, FRS. 239 36 1876, Sepi.6 0.0... Glasgow ., .| Prof. T. Andrews, M.D., F.R.S. 221 35 1877, Aug. 15...... Plymouth .. :| Prof. A. Thomson, M.D., F.R. 173 19 1878, Aug. 14...... Dublin ., 224) Rs FEA ee M.A., 201 18 1879, Aug. 20.,,.... Sheffield. .| Prof. G. J. Allman, M.D., F.R. 184 16 1880, Aug. 25 ...... Swansea... ainenc| une Cle Ramsay, LL.D., F.R. 144 ll 1881, Aug. 31 ...... SE QER 5 iteas .| Sir John Lubbock, Ba Pay 272 28 1882, Aug. 23 ......) Southampton Dr. O. W. Siemens, F.R 178 17 1883, Sept. 19 Southport .| Prof. A. Cayley, D.O.L., 203 60 1884, Aug. 27......) Montreal .. .| Prof. Lord Rayleigh, F. 235 20 1885, Sept.9 ...... Aberdeen .....,..,......| Sir Lyon Playfair, K.O. 225 18 1886, Sept.1 ....., Birmingham ,, .| Sir J. W. Dawson, O.M. 314 25 1887, Aug. 31...... Manchester ..... ‘| Sir H. E. Roscoe, D.O.L., rhe 428 86 1888, Sept.5\.i2.| Bath ....0 cctv cca Sir F. J. Bramwell, F.R.S. ......... 266 36 1889, Sept. 11 ......) Newcastle-on-Tyne...| Prof. W. H. Flower, O.B., F.R.S. 277 20 1890, Sept. 3 1", MGGOUN 57.55. .stetecsotees Sir F. A. Abel, O.B., F.R.S. 259 21 1891, Aug.19.,,,...| Oardiff ...., ‘| Dr. W. Huggins, F.R.S. 189 24 1892, Aug.3 ...... Edinburgh .,. .| Sir A. Geikie, LL.D., F. R. iS: 280 14 1893, Sept. 13,,.... Nottingham... ....| Prof. J. 8. Burdon Sanderson, F.R.S. 201 17 1894, Aug. 8 .| The Marquis of Salisbury,K. G. .F.R.S. 327 21 1895, Sept. 11 .| Sir Douglas Galton, K.C.B., BR. Ss. 214 13 1895, Sept.16 ...... .| Sir Joseph Lister, Bart., Pres. Riso 330 31 1897, Aug. 18, .| Sir John Evans, K.C.B., F.R.S. ......... 120 8 1898, Sept.7 , ...| Sir W. Orookes, F.R.S. ............. ss 281 19 1899, Sept. 13 .| Sir Michael Foster, K.C.B., Sec.R.S.... 296 20 1900, Sept. 5 ...... | Bradford’ 768.0482 Sir William Turner, D.O. Ly F.R. 3. 267 13 Ladies were not admitted by purchased tickets until 1843. + Tickets of Admission to Sections only. [Continued on p. x. ATTENDANCES AND RECEIPTS. 1X at Annual Meetings of the Association. j | Sums paid Old New hes enone on account Annual | Annual mites Ladies |Foreigners| Total anvine the of Grants Year Members | Members M fore for Scientific 8 Purposes — — — — — 353 _— — 1831 — _— _ _ _ _ _ _ 1832 _ —_— _ => —_ 900 —_ _ 1833 —_ _ _ _ _ 1298 _ £20 0 0 1834 —_ _— _— _ — —_ —_ 167 0 0 1835 —_ = _ — _ 1350 _— 435 0 0 1836 _ — — — — 1840 | — 922 12 6 1837 25 = = 1100* = 2400 | — 932 2 2| 1838 = — _— — 34 1438 _ 1595 11 0 1839 _ — —_ —_ 40 1353 _— 1546 16 4 1840 46 317 _— 60* — 891 = 1235 10 11 1841 75 376 33t 331* 28 1315 = 144917 8 1842 71 185 = 160 — — — 1565 10 2 1843 45 190 9 260 _— — _ 98112 8 1844 94 22 407 172 35 1079 =— 831.9 °9 1845 65 39 270 196 36 857 _ 685 16 0 1846 197 40 495 203 53 1320 — 208 5 4 1847 54 25 376 197 15 819 £707 0 0 275 1 8 1848 93 33 447 237 22 1071 963 0 0} 15919 6 1849 128 42 510 273 44 1241 1685 0 0| 34518 0 1850 61 47 244 141 37 710 620 0 0 391 9 7 1851 63 60 510 292 9 1108 1085 0 0| 304 6 7 1852 56 57 367 236 6 876 903 0 0} 205 0 0 1853 121 121 765 524 10 1802 1882 0 0} 38019 7 1854 142 101 1094 543 26 2133 2311 0 0} 48016 4 1855 104 48 412 346 9 1115 1098 0 0 73413 9 1856 156 120 900 569 26 2022 2015 0 0} 50715 4 1857 111 91 710 509 13 1698 19231 0 0} 61818 2 1858 125 179 1206 821 22 2564 2782 0 0 68411 1 1859 177 59 636 463 47 1689 1604 0 0 76619 6 1860 184 125 1589 791 15 3138 3944 0 0/1111 510 1861 150 57 433 242 25 1161 1089 0 0| 129316 6 1862 154 209 1704 1004 25 3335 3640 0 0/| 1608 3 10 1863 182 103 1119 1058 13 2802 2965 0 0/| 128915 8 1864 215 149 766 508 23 1997 2227 0 0| 1591 7 10 1865 218 105 960 771 11 2303 2469 0 0/175013 4 1866 193 118 1163 771 7 2444 2613 0 0) 1739 4 0 1867 226 117 720 682 45t 2004 2042 0 0} 1940 0 0 1868 229 107 678 600 17 1856 1931 0 0/| 1622 0 0 1869 303 195 1103 910 14 2878 3096 0 0/1572 0 0 1870 311 127 976 754 21 2463 2575 0 0| 1472 2 6 1871 280 80 937 912 43 2533 2649 0 0/| 1285 0 0 1872 237 99 796 601 11 1983 2120 0 0/| 168 0 0 1873 232 85 817 630 12 1951 1979 0 0| 115116 0 1874 307 93 884 672 17 2248 2397 0 0] 960 0 0 1875 331 185 1265 712 25 2774 3023 0 0| 1092 4 2 1876 238 59 446 283 11 1229 1268 0 0/1128 9 7 1877 290 93 1285 674 17 2578 2615 0 0} 72516 6 1878 239 74 529 349 13 1404 1425 0 0O| 1080 11 11 1879 ] 171 41 389 147 12 915 899 0 O| 731 7 7 1880 313 176 1230 514 24 2557 2689 0 0| 476 8 1 1881 253 79 516 189 21 1253 1286 0 0] 1126 111 1882 : 330 323 952 84 5 2714 3369 0 0/| 1083 3 3 1883 j 317 219 826 74 |26&60H.§) 1777 1855 0 0| 1173 4 0 1884 332 122 1053 447 6 2203 2256 0 0| 1385 0 O 1885 | 428 179 1067 429 11 2453 2532 0 0} 995 0 6 1886 510 244 1985 493 92 3838 4336 0 0| 118618 0 1887 399 100 639 509 12 1984 2107 0 0/1511 0 5 1888 412 113 1024 579 21 2437 2441 0 0/1417 O11 1889 368 92 680 334 12 1775 1776 0 0O| 78916 8 1890 341 152 672 107 35 1497 1664 0 0} 102910 0 1891 413 141 733 439 50 2070 2007 0 0 864 10 0 1892 328 57 773 268 17 1661 1653 0 0 907 15 6 1893 435 69 941 451 77 2321 2175 0 0 683 15 6 1894 290 31 493 261 22 1324 1236 0 0 977 15 5 1895 383 139 1384 873 41 3181 3228 0 0| 1104 6 1 1896 286 125 682 100 41 1362 1398 0 0/ 105910 8 1897 327 96 1051 639 33 2446 2399 0 0| 1212 0 0 1898 324 68 548 120 27 1403 1328 0 0O| 1430 14 2 1899 297 45 801 482 9 1915 1801 0 0] 107210 0 1900 _t Including Ladies. § Fellows ofthe American Association were admitted as Hon. Members for this Meeting. [Continued on p. xi. xX ATTENDANCES AND RECEIPTS. Table showing the Attendances and Receipts | | 4 7 Old Life | New Life | Date of Meeting Where held Presidents Members | Members | 3901, Sept. ul. Glasgow .| Prof. A. W. Riicker, D.Sc., Sec.R.S. ... 310 37 | 1902; Sept. 10......| Belfast .| Prof. J. Dewar, LL.D., F.R.S. ......... 243 21 1903, Sept. 9 ......) Southport ...| Sir Norman Lockyer, K.C.B., F.R.S. 250 | 21 1904, Aug. 17..,...| Oambridge......... ...| Rt. Hon, A. J. Balfour, M.P., F.R.S. 419 32 1905, Aug. 15...... South Africa ..,......| Prof.@.H. Darwin, LL.D.,F.R.S. ... 115 40 1906, Ang.1 1.00] York os... ...| Prof. E, Ray Lankester, LL.D., F.R.S. 322 10 1907, July 31...... Leicester . ...| Sir David Gill, K.0.B., F.R.S. 0.0.0... 276 19 1908, Sept. 2 ...,..} Dublin .., .! Dr. Francis Darwin, F. R.S. as 294 | 24 1909, Aug. 25,,,...) Winnipeg . ...| Prof, Sir J. J. Thomson, F.R.S. ...... Ls Sh eS 1910, Aug. 31 ...... Sheffield... ...| Rev. Prof, T. G. Bonney, F.R.S. 293 26 1911, Aug. 30...... Portsmouth , ...| Prof. Sir W. Ramsay, K.C.B. 284 21 1912, Sept. 4 .,,...| Dundee ......... Prof, E. A. Schifer, F.R.S........ cece 288 14 1913, Sept. 10 ...... Ee enenem ° .| Sir Oliver J. Lodge, F.R.S sd 376 40 1914, af aly-Sept... Australia .... Prof. W. Bateson, F.R.S. 172 13 1915, Sept. 7 ..,...) Manchester .. ........ Prof, A. Schuster, F.R.S. ..... 5! 242 19 | 1916, Sept.5 ...... Newcastle-on-Tyne... 164 12 1917 (No Meeting) i Sir Arthur Evans, F.R.S. ... ..... = 2 1918 (No Meeting) .........) ai a 1919, Sept.9 ..,... Bournemouth | Hon, Sir O. Parsons, K.O.B., F.R.S..., 235 47 1920, Aug. 24..,... PALO at ve canew css sanens | Prof. W. A. Herdman, C.B.E., F.R.S. 288 11 | | q Including 848 Members of the South African Association. tt Grants from the Caird Fund are not included in this and subsequent sums. ~~ ATTENDANCES AND RECEIPTS. Xl at Annual Meetings of the Association—(continued). { / Sums paid Old New Neaoe pe on account Annual = Annual cates Ladies Foreigners) Total |a ring the of Grants Year Members Members i | Meetin for Scientific H | 1n8 | Purposes | 374 131 794 246 20 1912 £2046 0 |£920 9 11 1901 | 314 86 647 305 6 1620 1644 0 | 947 0 O 1902 | 319 90 688 365 21 1754 | 1762 0 | 84513 2 1903 | 449 113 1338. a7 3) ) 121 2789 2650 0 | 887 18 11 1904 | 9377 | 411 430 181 | 16 2130 2492 0 | 928 2 2 1905 356 | 93 817 352 22 1972 1811 0 | 882 0 9 1906 339 / 61 659 951 | - 42 1647 1561 0 | 757 12 10 1907 | 465 | 112 1166 222 | 14: 2297 2317 0 |1157.18 8 1908 | 290¢* =| 162 789 90)24} 7 1468 1623 0 |1014 9 9 1909.. | 379 | 57 563 123) | 8 1449 | 1439 0 | 96317 0 1910 J 349 61 414 81 | 31 1241 1176 0 | 922 0 0 1911 | 368 | 95 1292 359 88 | 2504 | 2349 0 | 845 7 6 1912 480 | 149 1287 291 20 2643 «©2756 0 | 97817 1ft 1913 139 41605 539 || _— 21 | 6044|| 4873 0 |1086 16 4 1914 | | 287 116 §28* 141 | 8 | 1441 | 1406 0 1159 8 1915 250 76 251* (cecal _— | 826 821 0 | 715 18 10 1916 | — = a = —wiihvateedos a 42717 2 1917 _ _ _— — _ — | —_ 220 13 3 1918 254 102 688 * 153 | 3 1482 | 1736 0 | 160 uv O 1919 | | ; Annual Members | _ Ola inde Anpaal Tee liesce Students’ | aid eeeing | Meeting | Tiekets | Tekets | | | | \ Report ; only | 138 192 | atl. | 49 ed ee a | 1272 10 | 959 13 9 1920 | ** Including 137 Members of the American Association, || Special arrangements were made for Members and Associates joining locally in Australia, see Report, 1914, p.686. The numbers include 80 Members who joined in order to attend the Meeting of L’ Association Francaise at Le Havre. * * Including Students’ Tickets, 10s. REPORT OF THE COUNCIL, 1919-20. I. Sir T. E. Thorpe, C.B., has been unanimously nominated by the Council to fill the office of President of the Association for the year 1921-22 (Edinburgh Meeting). II. Resolutions referred by the General Committee, at the Bourne- mouth Meeting, for consideration, and, if desirable, for action, were dealt with as follows :— (a) The Council adopted a resolution from Section D, that in the case of persons applying for membership of the General Committee who are not known to the Council, the matter should be referred to the Organising Committee of the Section concerned. (b) The Council collaborated with the Conjoint Board of Scientific Societies in laying before the Prime Minister, H.M. Secretaries of State for the Colonies and for India, and the Governments of the Australian Commonwealth and the Union of South Africa, proposals for the collection and publication of scientific data relating to ex-German colonies (Resolutions of Sections E and H). (c) The Council expressed to H.M. Government the Association’s - approval of the proposal to establish a British Institute of Archeology in Egypt. (Resolution of Section H.) (d) The Council forwarded to the Board of Agriculture a represen- tation on the desirability of securing the uniform description and nomen- clature of ancient remains on Ordnance Survey Maps, and after correspondence with the Director-General of the Ordnance Survey have learnt that measures have been taken to this end. (Resolution of Section H.) (e) The Council referred back to the Committee of Section I a proposal that that Section should be entitled ‘ Physiology and Psychology,’ and that the Presidents in alternate years should represent the two branches of the Section. (f) The Council, after enquiry, felt unable to take action recom- mended by the Conference of Delegates in the matter of a representa- tion to H.M. Government on the use of taxes derived from motor-spirit and carriages for the improvement of roads. ———w REPORT OF THE COUNCIL, 1919-20. Xlil (g) A proposal from the Conference of Delegates, that the Board of Education should be asked to hold an enquiry on the teaching of geography, was referred to Section E. (h) The General Officers, on the instruction of the General Com- mittee, forwarded resolutions urging upon H.M. Government the necessity for supporting an organised scheme of scientific research to _ the Prime Minister, the Chancellor of the Exchequer, the First Lord of the Admiralty, the Secretary of State for War, the President of the Board of Trade, the Food Controller, and the Minister of Health. The Council have received from the Admiralty and from the War Office information on proposals for research. At the invitation of the Master-General of the Ordnance, the General Officers attended a Con- _ ference at the War Office, at which the Master-General, Lieut.-General Sir J. P. Du Cane, the Quarfermaster-General, Lieut.-General Sir T. E. Clarke, and the Director of Medical Services, Lieut.-General Sir T. - Goodwin, explained the organisation which has been adopted for scien- - tific research in connection with military services. teenie i tilt tinal III. The Council nominated as their representatives on the Joint Committee of the General Committee and Council on Grants, under the chairmanship of the President (Sir C. Parsons), Profs. W. A. Herdman, J. Perry, H. H. Turner, and J. L. Myres. This Committee was directed to report to the General Committee as well as to the Council, and its report, which the Council has approved, is appended: The Committee would favour the following procedure: That Re- _ search Committees proposed by the Sectional Committees of the British ~ Association and approved by the Committee of Recommendations be recommended by the Council for support by the Department of Scien- tific and Industrial Research, the Medical Research Board, or other _ bodies entrusted with the distribution of public funds, and that all Com- mittees, the work of which may be aided by such bodies, remain Committees of the Association responsible as before to the Sectional Committees. IV. The Council resumed consideration (deferred owing to the War) of certain resolutions referréd to them by the General Committee in Australia in 1914. e (2) The Council forwarded to the Australian Government a resolu- tion urging the need for legalising in Australia the metric system of weights and measures as an alternative (optional) system. (Resolution of Section A.) _ (0) The Council found it inexpedient to forward a resolution propos- ing a gravity survey in Australia. (Resolution of Section C.) X1V REPORT OF THE COUNCIL, 1919-20. (c) The Council forwarded to the Australian Government a resolu- tion urging the early production of the Australian sheets of the Carte du Monde au Millioniéme. (Resolution of Section E.) (d). The Council has still under consideration the proposal for the establishment of Bench-marks on Coral Islands, in the. Pacific. (Resolutions of Sections C and E.) V. The Department of Scientific and Industrial Research made a grant of £600 to the Association to meet the cost of certain specified researches for which Committees were appointed at the Sear Meeting. VI. The Research Fund initiated at Bournemouth now amounts to £1,888 16s. 6d. VII. Carrp Funp.—The Council made the following grants during the year, additional to annual grants previously made :— Fuel Economy Committee (additional to grant made by General Committee at Bournemouth) ie =< tod Committee on Training in Citizenship ; ‘ 10 Geophysical Committee of Royal Astronomical Society 10 Conjoint Board of Scientific Societies... he aif 10 VIII. CoNFERENCE oF DELEGATES and CoRRESPONDING SOCIETIES CoMMITTEE :— The following Nominations are made by the Council :— Conference of Delegates.—Mr. T. Sheppard (President), Mr. T. W. Sowerbutts (Vice-President), Mr. W. Mark Webb (Secretary). Corresponding Societies Commiltee.—Mr. W. Whitaker (Chair- man), Mr. W. Mark Webb (Secretary), Mr. P. J. Ashton, Dr. F. A. Bather, Rev. J. O. Bevan, Sir Edward Brabrook, Sir H. G. Fordham, Mr. A. L. Lewis, Mr. T. Sheppard, Rev. T. R. Stebbing, Mr. Mark L. Sykes, and the President and General Officers of the Association. On the proposal of a sub-committee of the Corresponding Societies Committee the Council, in the interests of economy, propose that the bibliography of scientific publications in the transactions of Correspond- ing Societies be not printed in future ir the Annual Report, and there- fore recommend the following change in the Rules :— Rule Chap, XI., 3 (u.):— *“There shall be inserted in the Annual Report of the Association a list of the papers published by the Corresponding Societies . . .”’ to read as follows :— “A list. shall be prepared of the papers published by the Corre- sponding Societies. REPORT OF THE COUNCIL, 1919-20. XV IX. The Council have received reports from the General Treasurer during the past year. His accounts have been audited and are presented to the General Committee. The Hon. Sir Charles Parsons has been nominated a Trustee of the Association, in the room of the late Lord Rayleigh. X. Power having been delegated to the Council by the General Committee to appoint ordinary members of Council to the vacancies caused by the resignation of Sir E. F. im Thurn and the appointment of Prof. J. lL. Myres as General Secretary, Sir R. Hadfield and Sir J. Scott Keltie were appointed. The retiring members of the Council are :— By seniority.—Sir Dugald Clerk, Prof. A. Dendy. By least attendance.—Prof. W. H. Perkin, Dr. E. J. Russell, Prof. E. H. Starling. The Council nominated the following members :— Mr. J. Barcroft, Prof. J. Stanley Gardiner, Sir W. J. Pope, leaving two vacancies to be filled by the General Committee without nomination by the Council. The full list of nominations of ordinary members is as follows :— Dr. E. F. Armstrong. Prof. A. Keith. Mr. J. Barcroft. Sir J. Scott Keltie. Prof. W. A. Bone. ‘Dr, F. A. Dixey. Sir F. W. Dyson. Prof, A. Fowler. Prof. J. Stanley Gardiner. Sir R. A. Gregory. Dr. E. H. Griffiths. Sir R. Hadfield. Sir S. F. Harmer. Prof. J. H. Jeans. Prof. A. W. Kirkaldy. Sir Daniel Morris. Sir W. J. Pope. Dr. W. H. R. Rivers. Miss E. R. Saunders. Prof. W. R. Scott. Sir A. Strahan. Mr. W. Whitaker. Dr. A. Smith Woodward. XI. Tue Genera Secretartes have been nominated by the Council as follows :— Prof. H. H. Turner. Prof, J. L. Myres. XII. The Genera] Treasurer and one or other of the General Secre- taries have been appointed representatives of the Association on the Conjoint Board of Scientific Societies. XIII. Prof. H. A. Lorentz has been appointed an Honorary Corre- sponding Member of the Association. Xvi REPORT OF THE COUNCIL, 1919-20. XIV. The following have been admitted as members of the General Committee :— Mr. W. B. Brierley. Dr. F. D. Chattaway. Mr. W. N. Cheesman. Miss M. C. Crosfield. Miss A. C. Davies. Prof. J. E. Duerden. Prof. A. J. Ewart. Mr. C. B. Fawcett. Dr. A. Holmes. Prof. F. Horton. Mr. A. Pearse Jenkin. Prof. W. Neilson Jones. Prof. A. A. Lawson. Prof. J. W. MacBain. Dr. R. MacDowall. Dr. J. 8. Owens. Mr. H. J. E. Peake. Dr. Mabel C. Rayner. Prof. E. W. Skeats. Mr. C. E. Stromeyer. Dr. W. M. Tattersall. Mr. Edwin Thompson. Lieut.-Col. Marett Tims. XV. A Meeting of Recorders and Local Sectional Secretaries for the Cardiff Meeting, together with the General Secretaries and Dr. W. E. Hoyle, Local Secretary, was held in New College, Oxford, on April 10- 12,1920. Though of an informal character, it was fruitful in discussion of arrangements at Cardiff and of other details in the working of the Association, and the Council hope that such a meeting may become ap annual institution. XVI. The Council received from the General Secretaries a detailed memorandum on the increased cost of printing, showing that the Asso- ciation could not hope to maintain printing at the level maintained before the war. The Council have put into force a number of alterations in the practice of the Association in this connection, and hope that the General Committee, after experience, will approve fhem. Taken together, it is hoped that they will save the Association over £600 a year. XVII. Finally, the Council record with deep regret the death of Mr. H. C. Stewardson, on May 1, 1920, after a short illness. His devoted service to the Association began in 1873, and being in his eightieth year he had intended to retire at the close of the financial year 1919-20. The Council have instructed the Assistant Secretiary to carry on the financial duties undertaken by Mr. Stewardson as Assistant Treasurer. ADDENDUM. A verbal addition was made to the above report, when it was pre- sented to the General Committee, expressing the profound regret of the Council at the death of Prof. J. Perry, General Treasurer, which took place on August 4, 1920.* The Council, at the same time, recorded their regret at the death of Sir Norman Lockyer, President of the Association in 1903. * The General Committee, after receiving this report and expressing concurrence with the sentiments of the Council, delegated to the Council the appointment of a General Treasurer for the year 1920-21, and appointed Prof. H. H. Turner as Acting Treasurer in the meantime. The Council, at its meeting on November 5, 1920, elected Dr. E. H. er Sc.D., D.Sc., LL.D., F.R.S., to be General Treasurer for the year GENERAL MEETINGS AT CARDIFF. XVii GENERAL MEETINGS AT CARDIFF. On Tuesday, August 24, at 8 p.m., in the Park Hall, the Hon. Sir Charles Parsons, K.C.B., F.R.S., resigned the office of President to Prof. W. A. Herdman, C.B.E., F.R.S. (See p. xxxi.) Prof. W. A. Herdman then assumed the chair and delivered an address, for which see p. 1. On Wednesday, August 25, at 8 p.m., a Reception was given in the City Hall by the Right Hon. the Lord Mayor of Cardiff. On Thursday, August 26, at 5 p.m., a Conference took place in the Assembly Hall, Technica] College, on Science Applied to Public Ser- vices, arising out of communications which had passed between the Association and Government Departments as the result of resolutions adopted by the General Committee at the Bournemouth Meeting (see Report, 1919, pp. Ixxiii-iv). The Conference was addressed by Mr. F. E. Smith, O.B.E., Director of Scientific Research, Admiralty, and others. On Thursday, August 26, at 8 p.m., in the Park Hall, Sir R. T. Glazebrook, K.C.B., F.R.S., delivered a discourse on ‘ Some Require- ments of Modern Aircraft.’ (See p. 384.) On Friday, August 27, at 8 p.m., the concluding General Meeting was held in the Park Hall. Sir Daniel Hall, K.C.B., F.R.S., delivered a discourse on ‘ A Grain of Wheat from the Field to the Table.’ (See p. 389.) After the above discourse the following resolution was unanimously adopted on the motion of the President :— ; That the cordial thanks of the British Association be extended to the Rt. Hon, the Lord Mayor and Corporation and the citizens of the city of Cardiff for their hearty welcome and for the facilities so generously afforded to the Association at the City Hall; to the Governing Bodies of the University of _ Wales, the University College of South Wales and Monmouthshire, the Tech- = nical College, the South Wales Institute of Engineers, and other institutions which have kindly placed their buildings and resources at the disposal ot the Association ; and, finally, to the Local Executive Committee, the Loca] Treasurers and Secretaries for their exertions in collecting the necessary funds and for the hospitality which has been freely offered to many members of the Associa- tion, as well as for the admirable arrangements made for the eighty-eighth annual meeting of the Association. PUBLIC OR CITIZENS’ LECTURES. The following public lectures were given in the Park Hall at 8 P.M. on the days stated :— August 23, Prof. J. Lloyd Williams on ‘ Light and Life.’ August 25, Prof. A. W. Kirkaldy on ‘ Present Industrial Conditions.’ August 28, Dr. Vaughan Cornish on ‘The Geographical Position f the British Empire,’ XVlli GENERAL TREASURER’S ACCOUNT. Dr. THE GENERAL TREASURER IN ACCOUNT ADVANCEMENT OF SCIENCE, RECEIPTS. See ey ote ie, pees ne To Balance brought forward :— Lloyds Bank, Birmingham ..............++8 Bebey conus voasasaskenasnaie Sesaa 1,728 17 3 Bank of England—Western Branch :— On ‘ Caird Fund’ ............6 deciapacsamenscoconcesccuccaccevocenial v. 50819 8 y General ACCOUN,,.......seessseeceeeeees Bence EE Perecee ERC iccc0 wage 4 12 ———_ 681 310 Cash in hand ......... ety SS Miseaaegsbaaeauevasghoccesaiiesesteee 0 1i1 2,410 3 0 Less Petty Oash overdrawn.,,,..,........++ peetecessretysteechntowe more 25 2 ; ———_ 2,407 17 10 Life Compositions (including Transfers) ..,............ Neh cnes ety hesaeuginexhaannnet 734 0 0 Annual Subscriptions . fh 707 0 0 New Annual Members 216 0 0 Sale of Associates’ Tickets . eons x 645 10 0 Sale of Ladies’ Tickets.....,..........+ (eee oats a) 152 0 0 Life Members (old) Additional Subscriptions ..,.......scscccsssersecsrcereesseees 446 13 0 Donations for Research :— C.Read,.2...6...-.,500 PR « 35 aenkbaah aarceseadahs stones sussh tena soapegens Neem 010 0 Rev. F. Smith, hice 2 2 0 Sir Hugh Bell............. vee, LOCHORO Sir Richard Robinson . ‘ 25 0 0 Sir Robert Hadfield .... 250 0 0 Sir Charles Parsons ,,.. v. 1,000 0 0 Sir Alfred Yarrow, . 500 0 0 Sir C. Bright .......... De cue cede deer eet ee eerate a 110 Scientific and Indust: Research Depar 600 0 0 Scientific Research Association ......., snadabbbse de : 1013 6 —— 2,489 6 6 Sale of Publications ..,.........+ Ronstcnceaerntepud’eanssSanncca en Se: nadeaee an srgtir Oo 224 11 10 Interest on Deposits :— Lloyds Bank, Birmingham ...............+« aeveesebatace aps abatycemunreses wastaadaced 17 20 ue ¥ ‘Oaird Gift’,....... ie 36 5 1 London County Westminster and Parr’s Bank............-..+ 36 3 9 8911 9 Unexpended Balances of Grants returned ...,....ssccceeerseeee Ghiksapt tee depenauees 5119 3 ” » Emir UM eee tera gs cnasptanesadaays seers ceak eactiacur cae OU Ont 101 19 3 Dividends on Investments :— Consols 24 per Cent. .., 81 8 0 India 3 per Cent. ........... ei 75 12.0 Great Indian Peninsula Railway A FF fe ae War Stock 5 per Cent. .....ci.cccesseteeesesceeeeee se 43 3 0 War Bonds 5 per Oent. ..,.... bitgdhesmeb thaeeeened BT ORE RE arte PI aupuddvesundveee 49 0 0 ——_ 272 10 2 Dividends on ‘Caird Fund’ Investments :— India 34 per Cent. ..... PRTG | AUELIE, ectertccvecssauthsocvescctcosestsoten Aen 64 7 4 Oanada 34 per Cent, (including extra 4 per Cent.) ...........ssecceseeeeeees 70 0 0 London and South-Western Railway Consolidated4 per Oent. Preference TOO ot eens treet enn er'e tine pee viva tee as tapemanmnnepiaxs resp vaucenksosnceos= 9s eeceaye ater 70 0 0 Londonand North-Western Railway Consolidated 4 per Oent. Preference Stock 4.5... igloos sbdeetuitbar ca dueneeaes vehetaeeed dan ach Caduchbdddabivesspdaabeos i 58 16 0 ——— 263 3 4 Investments. £ s. ad. 4,651 10 5 Consolidated 24 per Oent. Stock 3,600 0 O India 3 per Cent. Stock 879 14 9 Great Indian Peninsula Railway £43 ‘B’ Annuity 2,627 010 India 3} per Cent. Stock, ‘ Oaird Fund’ 2,100 0 0 London and North-Western Railway Consolidated 4 per Cent. Preference Stock, ‘Caird Fund’ 2,500 0 O Oanada 3} per Cent. (1930-50) Registered Stock ‘Caird Fund : 2,500 0 0 London and South-Western Railway Consolidated 4 per Cent. Preference Stock, ‘Oaird Fund’ 100 19 3 Sir Frederick Bramwell’s Gift of 2} per Cent. Self-Oumulating Consolidated Stock 863 210 War Loan 5 per Cent. Stock 1,400 0 O War Loan 5 per Cent., 1929-47 1,000 0 0 Lloyds Bank, Birmingham—Deposit Account, Sir J. Caird’s Gift for Radio-Activity Investigation, included in Balance at Bank £22,222 8 1 £8,750 3 8 — Value at 30th June, 1920, £13,416 8s, 1d, O_O OL <<< GENERAL TREASURER’S ACCOUNT. X1x WITH THE BRITISH ASSOCIATION FOR THE Cr. July 1, 1919, to June 30, 1920. PAYMENTS. S, 4. d. By Rent and Office Expenses ...........cccccccceeeeee Recetcccedtessetevesadtcers *OS3 RON MELEE Lea ee . 29214 8 Salaries and Travelling Expenses,, ee 7 f7 Printing, Binding, etc.................ccceeceeeeeeees Peneaestrarteg eaten ertncachinceeretentiteieveieieti ets 859 15 3 Grants to Research Oommittees :— Sls Liverpool Tidal Institute ............. SigarsavsccenisphadeesHapisses dbwendiee -. 150 0 Bronze Implements Committee .., SP 1LO® 0 Mathematical Tables .....,...... 30 0 Geology of Coal Seams .,,.............4. mig Free Places in Secondary Education 10 Stress Distribution ...............ssseescecees 80 Effects of War on Credit . nee 100 Replacement of Men by Women......... 30 Breeding Experiments on @nothera, & Pane Radiotelegraph Investigations,,,......... ... 100 Palaeolithic Site in Jersey... Rude Stone Monuments Annual Tables of Constants, Museums Committee .......... Railway Committee... 5 Heredity Committee .......... Palaeozoic Rocks Oommittee . 30 Committee on Lepidoptera ,...... 50 Absorption Spectra Committee ...... 10 International Language Committee Charts and Pictures Committee . Kiltorcan Rocks Committee.,,. i Zoological Bibliography....... aed Seismological Committee . nf essscooscososesooscoeSecooSoOCoCooOR ee i—) oeoocococecoococoococooscooocoso Stone Circles Committee .. tery HO RISROHASIUC ene token ceevevatsneseasuscevanscais roneere eco certer| Wareaaevnene oe » , 20 = One 130 Expenses Bournemouth Meeting ...... initrd peceorcereaee tc AG POLED STE SEE ; 260 8 7 F Oxford Meeting.............. 55 50 5 4 Grants made from ‘Caird Fund’ ................cc0-eceeee0s See consdaonsaae hbteeoepy te ite 240 U0 0 Balance at Lloyds Bank, Birmingham (with Interest accrued), includin, Sir James Caird’s Gift, Radio-Activity Investigation, of £1,000 and Interest accrued thereon .., _ .......sccccee « cesceecees .. 1,782 5 3 London Oounty Westminster and Parr’s Bank, Ltd... .ceeccccceceeececeeuee 1,854 10 9 Balance at Bank of England, Western Branch :— On ‘Caird Fund’ ............ Poasteectect cans ni Re’ hee-caseises’ | OGRE Se 0 gs LGrerieral Aceouamtiys; JA... ccesscsthe=-ctiWavtiecebdesseccencoese . 938 7 1 ———— 1,520 10 1 5,157 6 1 PPE EVG CAA BALANCE, «0, ccs tse ssacecaarcesestasavesccnactcesecsects As CARPE rt cr PEAS 109 ——— 5,158 6 10 £8,750 3 8 I have examined the above Account with the Books and Vouchers of the Association, and certify the same to be correct. I have also verified the Balances at the Bankers, and have ascertained tbat the Invest- ments are registered in the names of the Trustees, or held by the Bank of England on account of the Association. APPROVED— EDWARD BRABROOK A ARTHUR L. Bow Ley, } Auditors. W. B, Kuen, Chartered Accountant, 23 Queen Victoria Street, E.C. 4, August 13, 1920, a2 XxX RESEARCH COMMITTEES. RESEARCH COMMITTEES, Etc., APPOINTED BY THE GENERAL COMMITTEE, MEETING IN CARDIFF: Avaust, 1920. 1. (a) Receiving grants of money from the Association for expenses connected with research. (b) Receiving grants of money from the Associa- tion specifically for cost of printing Report. (e) Grant to be applied for from Public Funds. SECTION A.—MATHEMATICS AND PHYSICS. Seismological Investigations.—-Prof. H. H. Turner (Chairman), Mr. J. J. Shaw (Secretary), Mr. C. Vernon Boys, Dr. J. E. Crombie, Sir H. Darwin, Dr. C. Davison, Sir F. W. Dyson, Sir R. T. Glazebrook, Prof. C. G. Knott, Prof. H. Lamb, Sir J. Larmor, Prof. A. E. H. Love, Prof. H. M. Macdonald, Prof. H. C. Plummer, Mr. W. E. Plummer, Prof. R. A. Sampson, Sir A. Schuster, Sir Napier Shaw, Dr. G. T. Walker, Mr. G. W. Walker. (b) £10, (c) £90. { To assist work on the Tides.—Prof. H. Lamb (Chairman), Dr. A. T. Doodson (Secretary), Colonel Sir C. F. Close, Dr. P. H. Cowell, Sir H. Darwin, Dr. G. H. Fowler, Admiral F. C. Learmonth, Sir J. E. Petavel, Prof. J. Proudman, Major G. I. Taylor, Prof. D’Arcy W. Thompson, Sir J. J. Thomson, Prof. H. H. Turner. (b) £35, (c) £165. Annual Tables of Constants and Numerical Data, chemical, physical, and technological. —Sir E. Rutherford (Chairman), Prof. A. W. Porter (Secretary), Mr. A. FE. G. Egerton. (a) £40. Determination of Gravity at Sea.—Prof. A. E. H. Love (Chairman), Dr. W. G. Duffield (Secretary), Mr. 'T. W. Chaundy, Sir H. Darwin, Prof. A. S, Eddington, Major E, O. Henrici, Sir A. Schuster, and Prof. H.H. Turner. (a) £10. Calculation of Mathematical Tables.—Prof. J. W. Nicholson (Chairman), Dr. J. R. Airey (Secretary), Mr. T. W. Chaundy, Prof. L. N. G. Filon, Sir G. Greenhill, Colonei Hippisley, Prof. E. W. Hobson, Mr. G. Kennedy, and Profs. Alfred Lodge, A. E. H. Love, H. M. Macdonald, G. B. Mathews, G. N. Watson, and G. Webster. (a) £30, (c) £270. SECTION B.—CHEMISTRY. Colloid Chemistry and its Industrial Applications.—Prof. F. G. Donnan (Chairman), Mr. W. Clayton (Secretary), Mr. E. Ardern, Dr. E. F. Armstrong, Prof. W. M. Bayliss, Prof. C. H. Desch, Dr. A. E. Dunstan, Mr. H. W. Greenwood, Mr. W. Harrison, Mr. E. Hatschek, Mr. G. King, Prof. W. C. McC. Lewis, Prof. J. W. McBain, Dr. R. 8. Morell, Profs. H. R. Proctor and W. Ramsden, Dr. E. J. Russell, Mr. A. B. Searle, Dr. S. A. Shorter, Dr. R. E. Slade, Mr. Sproxton, Dr. H. P. Stevens, Mr. H. B. Stocks, Mr. R. Whymper. (a) £5, (c) For printing Report. Fuel Economy ; Utilisation of Coal; Smoke Prevention.—Prof. W. A. Bone (Chair- man), Mr. H. James Yates (Vice- Chairman), Mr. Robert Mond (Secretary), Mr. A. H. Barker, Prof. P. P. Bedson, Dr. W. S. Boulton, Mr. E. Bury, Prof. W. E. Dalby, Mr. E. V. Evans, Dr. W. Galloway, Sir Robert Hadfield, Bart., Dr. H. 8. Hele-Shaw, Mr. D. H. Helps, Dr. G. Hickling. Mr. D. V. Hollingworth, Mr. A. Hutchinson, Principal G. Knox, Mr. Michael Longridge, Prof. Henry Louis, Mr. G. E. Morgans, Mr. W. H. Patchell, Mr. E. D. Simon, Mr. A. T. Smith, Dr. J. E. Stead, Mr. C. E. Stromeyer, Mr. G. Blake Aide Sir Joseph Walton, Prof. W. W. Watts, Mr. W. B. Woodhouse, and Mr. C. H. Wordingham. (a) £15, (b) £20. T The Committee receives a grant of £100 from the Caird Fund. RESEARCH COMMITTEES. XXl Absorption Spectra and Chemical Constitution of Organic Compounds.—Sir J. J. Dobbie (Chairman), Prof. E. E. C. Baly (Secretary), Dr. A. W. Stewart. (a) £10, (b) £25. Research on Non-Aromatic Diazonium Salts.—Dr. F. D. Chattaway (Chairman), Prof. G T. Morgan (Secretary), Mr. P. G. W. Bayly and Dr. N. V. Sidgwick. (a) £10. To report on the present state of knowledge in regard of Infra-red Spectra.—Prof. E. E. C. Baly (Chairman), (vacant) (Secretary), Prof. W. C. McC. Lewis, Prof. F, A. Lindemann, Prof. T. W. Lowry, Prof. T. R. Merton. (a) £5. SECTION C.—GEOLOGY. The Old Red Sandstone Rocks of Kiltorcan, Ireland.—Prof. Grenville Cole (Chair- man), Prof. T. Johnson (Secretary), Dr. J. W. Evans, Dr. R. Kidston, and Dr. A. Smith Woodward. (a) £15. To excavate Critica] Sections in the Paleozoic Rocks of England and Wales.—Prof. W. W. Watts (Chairman), Prof. W. G. Fearnsides (Secretary), Prof. W. 8. Boulton, Mr. E. 8. Cobbold, Prof. E. J. Garwood, Mr. V. C. Illing, Dr. Lapworth, Dr. J. E. Marr, and Dr. W. K. Spencer. (a) £30, (b) £12. To consider the Nomenclature of the Carboniferous, Permo-carboniferous, and Per mian Rocks of the Southern Hemisphere.—Prof. T. W. Edgeworth David (Chair- man), Prof. E. W. Skeats (Secretary), Mr. W. S. Dun, Prof. J. W. Gregory, Sir T. H. Holland, Messrs. W. Howchin, A. E. Kitson, and G. W. Lamplugh, Dr. A. W. Rogers, Prof. A. C. Seward, Mr. D. M. 8. Watson, and Prof. W. G. Woolnough. (a) £25, (b) £5. SECTION D.—ZOOLOGY. To nominate competent Naturalists to perform definite pieces of work at the Marine Laboratory, Plymouth.—Prof. A. Dendy (Chairman and Secretary), Prof. E. 8. Goodrich, Prof. J. P. Hill, Prof. 8. J. Hickson, Sir E. Ray Lankester. (a) £200. Experiments in Inheritance in Silkworms.—Prof. W. Bateson (Chairman), Mrs. Merritt Hawkes (Secretary), Dr. F. A. Dixey, Prof. E. B. Poulton, Prof. R. C. Punnett. (a) £17 2s. 1d. Experiments in Inheritance of Colour in Lepidoptera.—Prof. W. Bateson (Chairman), The Hon. H. Onslow (Secretary), Dr. F. A. Dixey, Prof. E. B. Poulton. (a) £24, (b) £1. Zoological Bibliography and Publication.—Prof. E. B. Poulton (Chairman), Dr. F. A. Bather (Secretary), Mr. E. Heron-Allen, Dr. W. E. Hoyle, and Dr. P. Chalmers Mitchell. (a) £1. To summon meetings in London or elsewhere for the consideration of matters affecting the interests of Zoology, and to obtain by correspondence the opinion of Zoologists on matters of a similar kind, with power to raise by subscription from each Zoologist a sum of money for defraying current expenses of the organisation.— Prof. 8. J. Hickson (Chairman), Dr. W. M. Tattersall (Secretary), Profs. G. C. Bourne, A. Dendy, J. Stanley Gardiner, W. Garstang, Marcus Hartog, W. A. Herdman, J. Graham Kerr, R. D. Laurie, RF. W. MacBride, A. Meek, Dr. P. Chalmers Mitchell, and Prof. E. B. Poulton. (b) £20. Section F.—ECONOMIC SCIENCE AND STATISTICS. The Effects of the War on Credit, Currency, Finance, and Foreign Exchanges.— Prof. W. R. Scott (Chairman), Mr. J. E. Allen (Secretary), Prof C. F. Bastable, Sir E. Brabrook, Prof. L. R. Dicksee, Mr. B. Ellinger, Mr. E. L, Franklin, Mr. A. H. Gibson, Mr. C. W. Guilleband, Mr. F. W. Hirst, Prof. A. W. Kirkaldy, Mr. F. Lavington, Mr. E. Sykes, Sir J. C. Stamp, Mr. Hartley Withers, Mr. Hilton Young. (a) £50. XXli RESEARCH COMMITTEES. Section G.—ENGINEERING, To report on certain of the more complex Stress Distributions in Engineering Materials. —Prof. E. G. Coker (Chairman), Prof. L. N. G. Filon and Prof. A. Robertson (Secretary), Prof. A. Barr, Dr. Chas. Chree, Dr. Gilbert Cook, Prof. W. E. Dalby, Sir J. A. Ewing, Messrs. A. R. Fulton and J. J. Guest, Dr. B. P. Haigh, Profs. Sir J. B. Henderson, C. E. Inglis, F. C. Lea, A. E. H. Love, and W. Mason, Sir J. E. Petavel, Dr. F. Rogers, Dr. W. A. Scoble, Mr. R. V. Southwell, Dr. T. E. Stanton, Mr. C. E. Stromeyer, and Mr. J. S. Wilson. (b) £50. The Investigation of Gaseous Explosions, with special reference to temperature.— Sir Dugald Clerk (Chairman), (Vacant) (Secretary), Profs. W. A. Bone, F. W. Burstall, H. L. Callendar, and EH. G. Coker, Mr. D. L. Chapman, Prof. H. B. Dixon, Prof. A. H. Gibson, Sir R. T. Glazebrook, Dr. J. A. Harker, Colonel Sir H. C. L. Holden, Sir J. KE. Petavel, Mr. D. R. Pye, Mr. H. R. Ricardo, Captain H. R. Sankey, Prof. A. Smithells, and Mr. H. Wimperis. (b) £50. Srction H.—ANTHROPOLOGY. To excavate Early Sites in Macedonia.—Prof. Sir W. Ridgeway (Chairman), Mr. A. J. B. Wace (Secretary), Prof. R. C. Bosanquet, Mr. L. H. D. Buxton, Mr. 8. Casson, Dr. W. L. H. Duckworth, Prof. J. L. Myres. (a) £50. To excavate a Paleolithic Site in Jersey.—Dr. R. R. Marett (Chairman), Mr. G. de Gruchy (Secretary), Dr. C. W. Andrews, Mr. H. Balfour, Prof, A. Keith, and Colonel Warton. (b) £1. To report on the Classification and Distribution of Rude Stone Monuments.—Dr. R. R. Marett (Chairman), Prof. H. J. Fleure (Secretary), Mr. L. H. D. Buxton, Prof. J. L. Myres, Mr. H. Peake. (a) £25, (b) £1. To report on the Distribution of Bronze Age Implements.—Prof. J. L. Myres (Chair- man), Mr. H. Peake (Secretary), Dr. E. C. R. Armstrong, Dr. H. A. Auden, Mr. H. Balfour, Mr. L. H. D. Buxton, Mr. O. G. 8. Crawford, Sir W. Boyd Dawkins, Prof. H. J. Fleure, Mr. G. A. Garfitt, Dr. R. R. Marett, Mr. R. Mond, Sir C. H. Read, Sir W. Ridgeway. (a) £100, (b) £1. To conduct Archeological Investigations in Malta.—Prof. J. L. Myres (Chairman), Prof. A. Keith (Secretary), Dr. T. Ashby, Mr. H. Balfour, Dr. A. C. Haddon, Dr. R. R. Marett, and Mr. H. Peake. (a) £50. Section I.—PHYSIOLOGY. Ductless Glands.—Sir E. Sharpey Schafer (Chairman), Prof. Swale Vincent (Secretary), Dr. R. J. 8. McDowall. (c) £30. Section K.—BOTANY. Experimenta! Studies in the Physiology of Heredity.—Dr. F. F. Blackman (Chairman), Miss E. R. Saunders (Secretary), Profs. Bateson and Keeble. (a) £10, (c) £90. To continue Breeding Experiments on QOenothera and other Genera.—Dr. A. B. Rendle (Chairman), Dr. R. R. Gates (Secretary), Prof. W. Bateson, Mr. W. Brierley, Prof. O. V. Darbishire, Dr. M. C. Rayner. (a) £25. Primary Botanical Survey in Wales.—Dr. E. N. Miles Thomas (Chairman), Miss Wortham (Secretary), Miss Davey, Prof. F. W. Oliver, Prof. Stapledon, Principal A. H. Trow. (a) £20. RESEARCH COMMITTEES. XXill SECTION L.—EDUCATIONAL SCIENCE. Training in Citizenship.—Rt. Rev. J. E. C, Welldon (Chairman), Lady Shaw (Secretary), Sir R. Baden-Powell, Mr. C. H. Blakiston, Mr. G. D. Dunkerley, Mr. W. D. Eggar, Mr. C. R. Fay, Principal J. C. Maxwell Garnett, Sir R. A. Gregory, and Sir T. Morison. (a) £15, (b) £10, (c) £50. To inquire into the provision of Educational Pictures for display in schools.—Sir R. A. Gregory (Chairman), Mr. G. D. Dunkerley (Secretary), Mr, C. E. Browne, Miss L. J. Clarke, Mr. C. B. Fawcett, Mr. E. N. Fallaize, Prof. 8. J. Hickson, Mr. O. J. R. Howarth, Mr. C. G. T. Morison, Mr. H. J. E. Peake. Prof. 8S. H. Reynolds, Prof. H. E. Roaf, Sir Napier Shaw, Dr. T. W. Woodhead. (a) £6. 10s., (b) £16. To inquire into the work being done by University bureaux in furthering the inter- change of Students (particularly post-graduates) between home and foreign Universities, and to consider what steps can be taken to increase their spheres of action.—Mr. D. Berridge (Secretary). (a) £5. To inquire into the Practicability of an International Auxiliary Language.—Mr. W. B. Hardy (Chairman), Dr. E. H. Tripp (Secretary), Mr. E. Bullough, Prof. J. J. Findlay, Sir Richard Gregory, Dr. C. W. Kimmins, Dr. H. Foster Morley, Sir E. Cooper Perry, Prof. W. Ripman, Mr. F. Nowell Smith, Mr. A. E. Twentyman. (a) £7. 10s., (b) £15. , CORRESPONDING SOCIETIES. Corresponding Societies Committee for the preparation of their Report.—Mr. W. Whitaker (Chairman), Mr. W. Mark Webb (Secretary), Mr. P. J. Ashton, Dr. F. A. Bather, Rev. J. O. Bevan, Sir Edward Brabrook, Sir H. G. Fordham, Mr. A. L. Lewis, Mr. T. Sheppard, Rey. T. R. R. Stebbing, Mr. Mark L. Sykes, and the President and General Officers of the Association. (a) £40, (b) £30. 2. Not receiving Grants of Money. SECTION A.—MATHEMATICAL AND PHYSICAL SCIENCE. Radiotelegraphic Investigations.—Sir Oliver Lodge (Chairman), Dr. W. H. Eccles (Secretary), Mr. S. G. Brown, Dr. C. Chree, Sir F. W. Dyson, Prof. A. S. Eddington, Dr. Erskine-Murray, Profs. J. A. Fleming, G. W. O. Howe, H. M. Macdonald, and J. W. Nicholson, Sir H. Norman, Captain H. R. Sankey, Sir A. Schuster, Sir Napier Shaw, and Prof. H. H. Turner. Inyestigation of the Upper Atmosphere.—Sir Napier Shaw (Chairman), Mr. C. J. P. Cave (Secretary), Prof. S. Chapman, Mr. J. S. Dines, Mr. W. H. Dines, Sir R. T. Glazebrook, Col. E. Gold, Dr. H. Jeffreys, Sir J. Larmor, Mr. R. G. K. Lemp- fert, Prof. F. A. Lindemann, Dr. W. Makower, Sir J. E. Petavel, Sir A. Schuster, Dr. G. C. Simpson, Mr. F. J. W. Whipple, Prof. H. H. Turner. To aid the work of Establishing a Solar Observatory in Australia.—Prof. H. H. Turner, (Chairman), Dr. W. G. Duffield (Secretary), Rev. A. L. Cortie, Dr. W. J. 8. Lockyer, Mr. F. McClean, and Sir A. Schuster. SECTION C.—GEOLOGY. The Collection, Preservation, and Systematic Registration of Photographs of Geo- logical Interest.—Prof. E. J. Garwood (Chairman), Prof. 8. H. Reynolds (Secretary), Mr. G. Bingley, Dr. T. G. Bonney, Messrs. C. V. Crook, R. Kidston, and A. 8. Reid, Sir J. J. H. Teall, Prof. W.W. Watts, and Messrs. R. Welch and W. Whitaker. XXi1V RESEARCH COMMITTBES. To consider the preparation of a List of Characteristic Fossils.—Prof. P, F. Kendall (Chairman), Dr. W. T. Gordon (Secretary), Prof. W.S. Boulton, Dr. A. R. Dwerry- house, Profs. J. W. Gregory, Sir T. H. Holland, and 8. H. Reynolds, Dr. Marie C. Stopes, Dr. J. E. Marr, Prof. W. W. Watts, Mr. H. Woods, and Dr. A. Smith Woodward. To investigate the Flora of Lower Carboniferous times as exemplified at a newly- discovered locality at Gullane, Haddingtonshire.—Dr. R. Kidston (Chairman), Dr. W. T. Gordon (Secretary), Dr. J. 8. Flett, Prof, E. J. Garwood, Dr. J. Horne, and Dr. B. N. Peach. SECTION D.—ZOOLOGY. To aid competent Investigators selected by the Committee to carry on definite pieces of work at the Zoological Station at Naples.— Mr. E. 8. Goodrich (Chairman), Prof. J. H. Ashworth (Secretary), Dr. G. P. Bidder, Prof. F. 0. Bower, Drs. W. B. Hardy, Sir S. F. Harmer, Prof. 8. J. Hickson, Sir E. Ray Lankester, Prof. W. C. McIntosh, Dr. A. D, Waller. The collection of Marsupials for work upon (a) the reproductive apparatus and development, (b) the brain.--Prof. A. Dendy (Chairman), Dr. G. E. Nicholls (Secretary), Profs. W. J. Dakin, T. Flynn, J. P. Hill, E. B. Poulton, and G, Elliot Smith, Dr. Marett Tims. Section F.—ECONOMIC SCIENCE AND STATISTICS. Replacement of Men by Women in Industry.—Prof. W. R. Scott (Chairman), Miss Grier (Secretary), Miss Ashley, Mr. J. Cunnison, Mr. Daniels, Mr. C. R. Fay, Mr. J. E. Highton, and Professor A. W. Kirkaldy. Sxction H.—ANTHROPOLOGY. The Collection, Preservation, and Systematic Registration of Photographs of Anthro- pological Interest.—Sir C. H. Read (Chairman), Mr. E. N. Fallaize (Secretary), Dr. G. A. Auden, Dr. H. O. Forbes, Mr. E. Heawood, and Prof. J. L. Myres. To conduct Explorations with the object of ascertaining the Age of Stone Circles.— Sir C. H. Read (Chairman), Mr. H. Balfour (Secretary), Dr. G. A. Auden, Prof. Sir W. Ridgeway, Dr. J. G. Garson, Sir Arthur Evans, Sir W. Boyd Dawkins, Prof. J. L. Myres, Mr. A. L. Lewis, and Mr. H. Peake. To conduct Archeological and Ethnological Researches in Crete.—Mr. D. G. Hogarth (Chairman), Prof. J. L. Myres (Secretary), Prof. R. C. Bosanquet, Dr. W. L. H. Duckworth, Sir A. Evans, Sir W. Ridgeway, Dr. F. C. Shrubsall. To conduct Anthropometric Investigations in the Island of Cyprus.—Prof. J. L. Myres (Chairman), Dr. F. C. Shrubsall (Secretary), Mr. L. H. Dudley Buxton, Dr. A. C. Haddon. To co-operate with Local Committees in excavation on Roman Sites in Britain.— Sir W. Ridgeway (Chairman), Mr. H. J. E. Peake (Secretary), Dr. T. Ashby, Mr. Willoughby Gardner, Prof. J. L. Myres. To report on the present state of knowledge of the Ethnography and Anthropology of the Near and Middle East.—Dr. A. C. Haddon (Chairman), Mr. L. H. Dudley Buxton (Secretary), Mr. 8S. Casson, Prof. H. J. Fleure, Mr. H. J. E. Peake. t Grant of £100 from Caird Fund : see p. xxx. RESEARCH COMMITTEES, XXV To report on the present state of knowledge of the relation of early Palzolithic Instruments to Glacial Deposits.—Mr. H. J. E. Peake (Chairman), Mr. E. N. Fallaize (Secretary), Mr. H. Balfour. Section I.—PHYSIOLOGY. Electromotive Phenomena in Plants.—Dr. A. D. Waller (Chairman), Mrs. Waller (Secretary), Prof. J. B. Farmer, Mr. J. C. Waller. Food Standards and Man-power.—Prof. W. D. Halliburton (Chairman), Dr. A. D. Waller (Secretary), Prof. E. H. Starling. Section K.—BOTANY. To consider the possibilities of investigation of the Ecology of Fungi, and assist Mr. J. Ramsbottom in his initial efforts in this direction.—Mr. H. W. T. Wager (Chairman), Mr. J. Ramsbottom and Miss A. Lorrain Smith (Secretaries), Mr. W. B. Brierley, Mr. F. T. Brooks, Mr. W. N. Cheesman, Prof. T. Johnson, Prof. M. C. Potter, Mr. L. Carleton Rea, and Mr. E. W. Swanton. Section L.—EDUCATION. The Influence of School Books upon Eyesight.—Dr. G. A. Auden (Chairman), Mr. G. F. Daniell (Secretary), Mr. C. H. Bothamley, Mr. W. D. Eggar, Sir R. A. Gregory, Dr. N. Bishop Harman, Mr. J. L. Holland, Dr. W. E. Sumpner, and Mr. Trevor Walsh. CORRESPONDING SOCIETIES COMMITTEE. To take steps to obtain Kent’s Cavern for the Nation.—Mr. W. Whitaker (Chairman), Mr. W. M. Webb (Secretary), Prof. Sir W. Boyd Dawkins, Mr. Mark L. Sykes. Research Committees ‘in Suspense.’ The work of the following Committees is in suspense until further notice. The personnel of these Committees will be found in the Report for 1917. . SECTION D.-—ZOOLOGY. An investigation of the Biology of the Abrolhos Islands and the North-west Coast of Australia (north of Shark’s Bay to Broome), with particular reference to the _ Marine Fauna. Nomenclator Animalium Genera et Sub-genera. SECTION H.—ANTHROPOLOGY. To investigate the Physical Characters of the Ancient Egyptians. To prepare and publish Miss Byrne’s Gazetteer and Map of the Native Tribes of Australia. To investigate the Lake Villages in the neighbourhood of Glastonbury in connec- tion with a Committee of the Somerset Archzological and Natural History Society. SECTION K.—BOTANY. The Renting of Cinchona Botanic Station in Jamaica. XXVi RESOLUTIONS AND RECOMMENDATIONS. RESOLUTIONS AND RECOMMENDATIONS. The following Resolutions and Recommendations were referred to the Council (unless otherwise stated) by the General Committee at Cardiff for consideration and, if desirable, for action :— From Section A. That H.M. Stationery Office be asked to print the Tables on Congruence Solutions prepared by Lieut.-Col. A. Cunningham and Mr. T. G. Creak. From Sections A and E. (1) That this joint meeting of Sections A and E strongly urges upon the General Committee the desirability of printing in the report of the Association the paper read before it by Principal E. H. Griffiths and Major E. O. Henrici on ‘The Need for a Central British Institute for Training and Research in Surveying, Hydrography, and Geodesy’ *; and (2) that the meeting calls the attention of the Council to the urgency of the question at the present time, and begs that the Council will again give attention to the subject. From Section B. That Section B requests the Council to recommend to the appropriate autho- rities the great desirability of continuing the experiments on the production of industrial alcohol now in progress, by aid of the installations now existing in Government establishments. From Section C. That the Committee of Section C intimate to the Council that it regards the forecasting of the length of Committee reports as in many cases impossible. From Section D. Unanimously agreed by the Committee of Section D (thirty-nine present) that it be a recommendation to the Zoology Organisation Committee that no scheme of payment of professional zoologists in the service of the State is satisfactory which places them on a lower level than that of the higher grade of the Civil Service. (The above Resolution received the support of representatives of other Sections, and the General Committee directed that its consideration and any action upon it should take account of the position of workers in other branches of science.) From Section D. That Section D is profoundly impressed with the importance of urging the initiation of a further National Expedition for the Exploration of the Ocean, and requests the Council of the British Association to appoint a Committee to take the necessary steps to impress this need upon His Majesty’s Government and the nation. ; (The above Resolution was supported by the Committees of all Sections concerned.) * This Recommendation was sanctioned by the General Committee. RESOLUTIONS AND RECOMMENDATIONS. XXVil From Section E. That this meeting of Section E of the British Association, being convinced by the results already obtained of the value as an educational instrument and as a work of national importance of the scheme recently initiated by the Welsh Department of the Board of Education for the collection of Rural Lore and Regional Survey material through the medium of the elementary and secondary schools and colleges, heartily approves the same, and expresses the earnest hope that the scheme may be widely taken up throughout the country. From Section H (see preceding Resolution). That the Committee of Section H, Cardiff, August 1920, views with interest and appreciation the scheme of the Welsh Department of the Board of Educa- tion for the collection of Rural Lore through the agency of the schools, and hopes that steps may be taken to apply the scheme, mutatis mutandis, to other parts of Great Britain. From Section EH. That the Committee of Section E (Geography) of the British Association for the Advancement of Science begs leave to ask the President of the Board of Education to give schools permission to include geography as a subject on a level with the other subjects in advanced courses of suitable type in mathematics and science, in classics, and in modern studies. From Section E. The Committee of Section E of the British Association meeting at Cardiff (1920) expresses its appreciation of the opportunity of co-operation in the wor of the National Committee on Geographical Research afforded by the Royal Society, but it begs leave to suggest that the purpose might be served more fully if the Section were permitted to nominate a representative for a period of two or three years in place of the nomination of the President of the Section who retires annually. The Committee begs to suggest, if their recommendation be adopted, that Prof. J. L. Myres be nominated as their representative. From Section H. That the following Committees be authorised to obtain financial assistance from sources other than the Association * : (a) Archeological Investigations in Malta. (6) Bronze Age Implements. (c) Paleolithic Site in Jersey. (d) Rude Stone Monuments. From Section H. That this Association urges upon the Government of the Union of South Africa the desirability of instituting an Ethnological Bureau for the purpose of studying the racial characteristics, languages, institutions, and beliefs of the native population of South Africa, in order that any attempt which may be made to bring this population into closer touch with the course of social and economic development in South Africa may be based upon a scientific knowledge and an understanding of its psychology, mode of life, and institutions. * This Recommendation was sanctioned by the General Committee. XXVill RESOLUTIONS AND RECOMMENDATIONS. From Section H. That this Association would urge upon the Government of Western Australia the desirability of instituting forthwith an anthropological survey of the aboriginal population now living under Government protection on Government reservations, stations, and elsewhere in Western Australia, in order that a record may be made of the physical measurements, languages, customs, and beliefs of these tribes, before this material, of great scientific importance, is lost by the death of the older members of the tribes or impaired in value by contact with civilisation. From Section H. That the attention of this Association having been called to the present deplorable condition of the aboriginal population of Central Australia, it would urge upon the Federal Government of the Commonwealth of Australia, the Government of South Australia, and the Government of Western Australia the necessity for (1) the declaration of an absolute reservation on some part of the lands at present inhabited by these tribes, such as, for instance, the Musgrave, Mann, and Tomkinson Ranges, upon which all may be located under State pro- tection and supervision; and (2) the institution of a medical service for the aborigines to check the ravages of tuberculosis and other diseases now rife among them. From Section H. That in future years Associations for the Advancement of Science in the Dominions and in Foreign Countries be invited to send official representatives to attend the annual meetings of this Association. From Section H. Recommendations * in reference to printing of reports of Research Committees 1919-20 : (a) Archeological Investigations in Malta :—That the Government of Malta be asked to contribute £50 towards the cost of printing this report in the Journal of the Royal Anthropological Institute on the condition that copies of the report will be available for sale in the Island of Malta. (6) That Mr. Willoughby Gardner’s report on the Excavations at Dinorben in 1919-20 be printed, in abstract only, as an appendix to the report of the Roman Sites Committee for 1919-20. From Sections H and L. That this Association, while viewing with approbation the recent regulation of the Board of Education (Circular 1153, March 31, 1908), where anthropo- metric observations may be included in the medical inspection of Continuation Schools, would urge upon the Board the desirability of extending this provision to all schools in receipt of Government grant for a limited period of, say, five years, in order that, as a result of such a survey, standards of comparison may be available in the future for the purpose of both medical inspection and scientific investigation. From Section I. The Committee of Section I recommend to the General Committee of the British Association that a separate Section of Psychology be formed. (The above Recommendation was supported by representatives of Section L, aoe se approved by the General Committee subject to the approval of the ouncil. * These Recommendations were sanctioned by the General Committee. RESOLUTIONS AND RECOMMENDATIONS. XXiX From Section K. That Government support is desired for the afforestation experiments on pit-mounds being conducted by the Midland Reafforesting Committee. From Section L. Section L ask the Council to give power to the Organising Committee of Section L, if they think fit, to allow a book upon Citizenship, based. upon the syllabus in Appendix I. of the 1920 Report of the Committee upon Training in Citizenship, to be published, with a foreword to the effect that the book has the approval of the Organising Committee of Section L of the British Asso- ciation. From Section L. That 500 short copies of the Reports on Museums and on Training in Citizen- ship (1920) be printed from the standing type.* * This Recommendation was sanctioned by the General Committee. »:0:0.4 THE CAIRD FUND. THE CAIRD FUND. An unconditional gift of 10,000. was made to the Association at the Dundee Meeting, 1912, by Mr. (afterwards Sir) J. K. Caird, LL.D., of Dundee. The Council, in its report to the General Committee at the Bir- mingham Meeting, made certain recommendations as to the administra- tion of this Fund. These recommendations were adopted, with the Report, by the General Committee at its meeting on September 10, 1913. The following allocations have been made from the Fund by the Council to August 1920 :-— Naples Zoological Station Committee (p. xxiv).—501. (1912-13) ; 1001. (1913-14) ; 100/. annually in future, subject to the adoption of the Com- mittee’s report. (Reduced to 501. during war.) Seismology Committee (p. xx).—100/. (1913-14) ; 1007. annually in future, subject to the adoption of the Committee’s report. Radiotelegraphic Committee (p. xxiii).—500/. (1913-14). Magnetic Re-survey of the British Isles (in collaboration with the Royal Society).—250/. Committee on Determination of Gravity at Sea (p. xx).—1001. (1914-15). Mr. F. Sargent, Bristol University, in connection with his Astro- nomical Work.—101. (1914). Organising Committee of Section F' (Economics), towards expenses of an Inquiry into Outlets for Labour after the War.—100l. (1915). Rev. T. HE. R. Phillips, for aid in transplanting his private observa- tory.—20/. (1915). Committee on Fuel Economy (p. xx).—251. (1915-16), 107. (1919-20). Committee on Training in Citizenship (p. xxiii).—10/. (1919-20). Geophysical Committee of Royal Astronomical Society.—101. (1920). Conjoint Board of Scientific Societies.—10I. (1920). Sir J. K. Caird, on September 10, 1913, made a further gift of 1,000/. to the Association, to be devoted to the study of Radio-activity. INAUGURAL GENERAL MEETING. XXxl INAUGURAL GENERAL MEETING. Tuesday, August 24, 1920. In the course of his speech introducing his successor, the President, the Hon. Sir Charles Parsons, K.C.B., F.R.S., said:— The General Committee have authorised me to send the following telegram to His Majesty the King :— Your Maszsty, The members of the British Association for the Advancement of Science desire to express their loyal devotion to your Majesty, and at this their meeting in the Principality of Wales hope that they may be permitted to congratulate your Majesty on the splendid work done by the Prince of Wales, which has drawn towards him the thoughts and the hearts of the whole Empire. We have to record with deep regret that since our meeting at Bournemouth last year the Association has lost two of its most devoted and valued officers. Professor John Perry, F.R.S., General Treasurer of the Association since 1904, died at his London residence on August 4 at the age of seventy. He had only returned two months ago from a long voyage round South America, undertaken for the benefit of his health. It had, however, not produced the desired result ; the affection of his heart increased, and the end came suddenly. Professor Perry was widely known as an eminent mathematician, and as one who had directed most of his life to introducing mathematics as a practical science— his numerous books are well known in this country and America, and have been translated into many foreign languages. He was at one time assistant to Lord Kelvin, and helped in the perfecting of the Kelvin electrostatic volt- meter. In association with Ayrton he was a pioneer in the early developments of electrical instruments, storage batteries, and on the applications of elec- tricity. He was a Past-President of the Institute of Electrical Engineers and of the Physical Society. One of his most famous lectures was on ‘ Spinning Tops,’ delivered at the British Association meeting at Leeds in 1890, and his recent work in the perfecting of the gyroscopic compass is well known. His genial, warm-hearted kindness endeared him not only to his wide circle of friends, but also to his colleagues and students, and there are few members of this Association who do not feel a blank that it is difficult to fill. Henry Charles Stewardson, Assistant Treasurer of the British Association for many years, entered the services of the Association in 1873 in a clerical capacity, but, through his ability for finance, soon became Assistant Treasurer, and the Association undoubtedly owes much to his careful economies and to his accurate forecasts of the balance available for grants to research, which guided the Committee of Recommendations each year. He missed no annual meeting, and many members gratefully remember his help and courtesy in the Reception Room. His health was failing at the last meeting, but he continued to discharge his duties until within four days of his death, on May 1 last, in his eightieth year. The death of Sir Norman Lockyer, F.R.S., on Monday of last week, deprives the world of a great astronomer, and the nation of a force which it can ill afford to lose. By applying the spectroscope to the sun he furnished the means of studying its surface without waiting for an eclipse; revealed in 1868 the prominences as local disturbances in the chromosphere ; and observed in the sun the gas, named by him helium, and afterwards identified on the earth by Sir William Ramsay. More than half a century ago Sir Norman founded that admirable scientific journal ‘Nature.’ He also founded the British Science XXXii INAUGURAL GENERAL MEETING. Guild in 1905. His Presidential Address to the British Association at South- port sixteen years ago, on ‘ The Influence of Brain Power on History,’ attracted wide attention, but it has taken the greatest war in history to awaken national consciousness to its significance. I have now the pleasure of introducing to you my successor in this chair, an eminent biologist who has directed his great talents with indefatigable energy to the study of the life that exists in the vast spaces and depths of the ocean, which covers nearly three-fourths of our globe. Few people give much thought to the ocean beyond the fact that it carries our ships and is the source of most of the fish which we eat. But the work of investigating what goes on within the ocean, a work in which Professor Herdman has taken so arduous and prominent a part, has revealed a life within it, both vegetable and animal, of great complexity and of enormous magnitude, but governed by laws chemical and physical which are being gradually discovered. It is indeed difficult to realise, as Professor Herdman has stated, that in some seas a cubic mile of water may contain as much as 30,000 tons of living organisms whose life history depends on the light of the sun, thermal currents in the ocean, and seasonal changes, and that those organisms form the staple food of the fishes which we eat. The difficulties of these investigations must have been enormous, requir- ing the resources of science, consummate skill, and indefatigable energy to overcome them. Many years ago Professor Herdman created a fisheries labora- tory in the University of Liverpool, created and brought into co-operation with it. a biological station at Port Erin, and arranged periodical ocean trips for dredging and collecting marine organisms. A year ago he endowed a chair of oceanography at Liverpool, the first on this subject in the British Isles. He also founded, two years earlier, the chair of geology in memory of his only son George Herdman, one of those young men of brilliant promise killed in the war. His enthusiasm and sympathy have made him beloved by his pupils, as indeed by zoologists in general, and his work has led to the throwing of much additional light on the marine life of our globe. The President-Elect, Professor W. A. Herdman, C.B.E., D.Sc., LL.D., F.R.S., then took the chair, and delivered the Presidential Address, which is printed below (pp. 1-33). The following gracious reply was received from His Majesty the King to the telegram quoted on p. xxxi:— I have received with much pleasure and satisfaction the message which you have addressed to me on behalf of the members of the British Association, and in thanking them for their loyal assurances to myself I feel greatly touched at the kind references to my son, which are the more appreciated coming as these do from the members of this distinguished Society assembled in the Principality of Wales. I shall follow your deliberations with close interest, and I gratefully recognise all that is being done for the advancement of civilisation by the men of science. Gerorce R.I. CARDIFF: 1920. ADDRESS BY WILLIAM A. HERDMAN, C.B.E., D.Sc., Sc.D., LL.D., F.R.S., Professor of Oceanography in the University of Liverpool, PRESIDENT. Oceanography and the Sea-Fisheries. Ir has been customary, when occasion required, for the President to offer a brief tribute to the memory of distinguished members of the Association lost to Science during the preceding year. These, for the most part, have been men of advanced years and high reputation, who had completed their life-work and served well in their day the Associa- tion and the sciences which it represents. Such are our late General Treasurer, Professor Perry, and our Past-President, Sir Norman Lockyer, of whom the retiring President has just spoken.‘ We have this year no other such losses to record; but it seems fitting on the present occasion to pause for a moment and devote a grateful thought to that glorious band of fine young men of high promise in science who, in the years since our Australian meeting in 1914, gave, it may be, in brief days and months of sacrifice, greater service to humanity and the advance of civilisation than would have been possible in years of normal time and work. A few names stand out already known and highly honoured—Moseley, Jenkinson, Geoffrey Smith, Keith Lucas, Hopkinson, Gregory, and more recently Leonard Doncaster—all grievous losses; but there are also others, younger members of our Association, who had not yet had opportunity for showing accomplished work, but who equally gave up all for a great ideal. I prefer to offer a collective rather than an individual tribute. Other young men of science will arise and carry on their work—but the gap in our ranks remains. Let their successors remember that it serves as a reminder of a great example and of high endeavour worthy of our gratitude and of permanent record in the annals of Science. At the last Cardiff Meeting of the British Association in 1891 you had as your President the eminent astronomer Sir William Huggins, who discoursed upon the then recent discoveries of the spectroscope in relation to the chemical nature, density, temperature, pressure and even the motions of the stars. From the sky to the sea is a long drop; but the sciences ia both have this in common, that they deal with } See p, Xxx., ante, 1920 B 2 PRESIDENT’S ADDRESS. fundamental principles and with vast numbers. Over three hundred years ago Spenser in the ‘ Faerie Queene ’ compared ‘ the seas abundant progeny ’ with ‘ the starres on hy,’ and recent investigations show that a litre of sea-water may contain more than a hundred times as many living organisms as there are stars visible to the eye on a clear night. During the past quarter of a century great advances have been made in the science of the sea, and the aspects and prospects of sea- fisheries research have undergone changes which encourage the hope that a combination of the work now carried on by hydrographers and biologists in most civilised countries on fundamental problems of the ocean may result in a more rational exploitation and administration of the fishing industries. And yet even at your former Cardiff Meeting thirty years ago there were at least three papers of oceanographic interest—one by Professor Osborne Reynolds on the action of waves and currents, another by Dr. H. R. Mill on seasonal variation in the temperature of lochs and estuaries, and the third by our Honorary Local Secretary for the present meeting, Dr. Evans Hoyle, on a deep-sea tow-net capable of being opened and closed under water by the electric current. It was a notable meeting in several other respects, of which I shall merely mention two. In Section A, Sir Oliver Lodge gave the historic address in which he expounded the urgent need, in the interests of both science and the industries, of a national institution for the promotion of physical research on a large scale. Lodge’s pregnant idea put forward at this Cardiff Meeting, supported and still further elaborated by Sir Douglas Galton as President of the Association at Ipswich, has since borne notable fruit in the establishment and rapid development of the National Physical Laboratory. The other outstanding event of that meeting is that you then appointed a committee of eminent geologists and naturalists to consider a project for boring through a coral reef, and that led during following years to the successive expeditions to the atoll of Funafuti in the Central Pacific, the results of which, reported upon eventually by the Royal Society, were of great interest alike to geologists, biologists, and oceanographers. Dr. Huggins, on taking the Chair in 1891, remarked that it was over thirty years since the Association had honoured Astronomy in the selection of its President. It might be said that the case of Oceano- graphy is harder, as the Association has never had an Oceanographer as President—and the Association might well reply ‘ Because until very recent years there has been no Oceanographer to have.’ If Astronomy is the oldest of the sciences, Oceanography is probably the youngest. Depending as it does upon the methods and results of other sciences, it was not until our knowledge of Physics, Chemistry, and Biology was PRESIDENT’S ADDRESS. 3 relatively far advanced that it became possible to apply that knowledge to the investigation and explanation of the phenomena of the ocean. No one man has done more to apply such knowledge derived from various other subjects and to organise the results as a definite branch of science than the late Sir John Murray, who may therefore be regarded as the founder of modern Oceanography. It is, to me, a matter of regret that Sir John Murray was never President of the British Association. I am revealing no secret when I tell you that he might have been. On more than one occasion he was invited by the Council to accept nomination, and he declined for reasons that were good and commanded our respect. He felt that the necessary duties of this post would interfere with what he regarded as his primary life-work—oceanographical explorations already planned, the last of which he actually carried out in the North Atlantic in 1912, when over seventy years of age, in the Norwegian steamer Michael Sars, along with his friend Dr. Johan Hjort. Anyone considering the subject-matter of this new science must be struck by its wide range, overlapping as it does the borderlands of several other sciences and making use of their methods and facts in the solution of its problems. It is not only world-wide in its scope but extends beyond our globe and includes astronomical data in their relation to tidal and certain other oceanographical phenomena. No man in his work, or even thought, can attempt to cover the whole ground—although Sir John Murray, in his remarkably comprehensive ‘ Summary ’ volumes of the Challenger Expedition and other writings, went far towards doing so. He, in his combination of physicist, chemist, geologist and biologist, was the nearest approach we have had to an all-round Oceano- grapher. The International Research Council probably acted wisely at the recent Brussels Conference in recommending the institution of two International Sections in our subject, the one of physical and the other of biological Oceanography—although the two overlap and are so interdependent that no investigator on the one side can afford to neglect the other.* On the present occasion I must restrict myself almost wholly to the latter division of the subject, and be content, after brief reference to the 2 The following classification of the primary divisions of the subject may possibly be found acceptable :— Ag hae | Oceanography Geography | I | | | Hydrography Metabolism Bionomics Tidology (Physics, &¢.) (Bio-Chemistry) (Biology) (Mathematics) BZ 4 PRESIDENT’S ADDRESS. founders and pioneers of our science, to outline a few of those investi- gations and problems which have appeared to me to be of fundamental importance, of economic value, or of general interest. Although the name Oceanography was only given to this branch of science by Sir John Murray in 1880, and although according to that veteran oceanographer Mr. J. Y. Buchanan, the last surviving member of the civilian staff of the Challenger, the science of Oceanography was born at sea on February 15, 1873,* when, at the first official dredging station of the expedition, to the westward of Teneriffe, at 1525 fathoms, everything that came up in the dredge was new and led to fundamental discoveries as to the deposits forming on the floor of the ocean, still it may be claimed that the foundations of the science were laid by various explorers of the ocean at much earlier dates. Aristotle, who took all knowledge for his province, was an early oceanographer on the shores of Asia Minor. When Pytheas passed between the Pillars of Hercules into the unknown Atlantic and penetrated to British seas in the fourth century B.c., and brought back reports of Ultima Thule and of a sea to the North thick and sluggish like a jelly-fish, he may have been recording an early planktonic observation. But passing over all such and many other early records of phenomena of the sea, we come to surer ground in claiming, as founders of Oceanography, Count Marsili, an early investigator of the Mediterranean, and that truly scientific navigator Captain James Cook, who sailed to the South Pacific on a Transit of Venus expedition in 1769 with Sir Joseph Banks as naturalist, and by subsequently circumnavigating the South Sea about latitude 60° finally disproved the existence of a great southern continent; and Sir James Clerk Ross, who, with Sir Joseph Hooker as naturalist, first dredged the Antarctic in 1840. The use of the naturalist’s dredge (introduced by O. F. Miller, the Dane, in 1799) for exploring the sea-bottom was brought into promin- ence almost simultaneously in several countries of North-West Europe —by Henri Milne-Edwards in France in 1830, Michael Sars in Norway in 1835, and our own Edward Forbes about 1832. The last-mentioned genial and many-sided genius was a notable figure in several sections of the British Association from about 1836 onwards, and may fairly be claimed as a pioneer of Oceanography. In 1839 he and his friend the anatomist, John Goodsir, were dredging ° Others might put the date later. Significant publications are Sir John Murray’s Summary Volumes of the Challenger (1895), the inauguration of the ‘Musée Océanographique’ at Monaco in 1910, the foundation of the ‘Institut Océanographique’ at Paris in 1906 (see the Prince of Monaco’s letter to the Minister of Public Instruction), and Sir John Murray’s little book The Ocean (1913), where the superiority of the term ‘Oceanography ’ ‘to ‘Thalassography ’ (used by Alexander Agassiz) is discussed, he ,PRESIDENT’S ADDRESS. 5 in the Shetland seas, with results which Forbes made known to. the meeting of the British Association at Birmingham that summer, with such good effect that a “Dredging Committee’ * of the Association was formed to continue the good work. Valuable reports on the discoveries of that Committee appear in our volumes at intervals during the subse- quent twenty-five years. It has happened over and over again in history that the British Association, by means of one of its research committees, has led the way in some important new research or development of science and has shown the Government or an industry what wants doing and how it can be done. We may fairly claim that the British Association has inspired and fostered that exploration of British seas which through marine biological investigations and deep-sea expeditions has led on to modern Oceanography. Edward Forbes and the British Association Dredging Committee, Wyville Thomson, Carpenter, Gwyn Jeffreys, Norman, and other naturalists of the pre-Challenger days—all these men in the quarter-century from 1840 onwards worked under research com- mittees of the British Association, bringing their results before successive meetings; and some of our older volumes _enshrine classic reports on dredging by Forbes, McAndrew, Norman, Brady, Alder, and other notable naturalists of that day. These local researches paved the way for the Challenger and other national deep-sea expeditions. Here, as in other cases, it required private enterprise to precede and stimulate Government action. It is probable that Forbes and his fellow-workers on this ‘ Dredging Committee’ in their marine explorations did not fully realise that they were Opening up a most comprehensive and important department of knowledge. But it is also true that in all his expeditions—in the British seas from the Channel Islands to the Shetlands, in Norway, in the Mediterranean as far as the Algean Sea—his broad outlook on the problems of nature was that of the modern oceanographer, and he was the spiritual ancestor of men like Sir Wyville Thomson of the Challenger Expedition and Sir John Murray, whose accidental death a few years ago, while still in the midst of active work, was a grievous loss to this new and rapidly advancing science of the sea. * Forbes in these marine investigations worked at border-line problems, dealing for example with the relations of Geology to Zoology. 4 “For researches with the dredge, with a view to the investigation of the marine zoology of Great Britain, the illustration of the geographical distri- bution of marine animals, and the more accurate determination of the fossils of the pieistocene period: under the superintendence of Mr. Gray, Mr. Forbes, Mr. Goodsir, Mr. Patterson, Mr, Thompson of Belfast, Mr. Ball of Dublin, Dr. George Johnston, Mr. Smith of Jordan Hill, and Mr. A. Strickland, £60.’ Report for 1839, p. xxvi. 6 PRESIDENT’S ADDRESS. * and the effect of the past history of the land and sea upon the distri- bution of plants and animals at the present day, and in these respects he was an early oceanographer. For the essence of that new subject is that it also investigates border-line problems and is based upon and makes use of all the older fundamental sciences—Physics, Chemistry and Biology—and shows for example how variations in the great ocean currents may account for the movements and abundance of the migratory fishes, and how periodic changes in the physico-chemical characters of the sea, such as variations in the hydrogen-ion and hydroxyl-ion concentration, are correlated with the distribution at the different seasons of the all-important microscopic organisms that render our oceanic waters as prolific a source of food as the pastures of the land. Another pioneer of the nineteenth century who, I sometimes think, has not yet received sufficient credit for his foresight and initiative, is Sir Wyville Thomson, whose name ought to go down through the ages as the ieader of the scientific staff on the famous Challenger Deep-Sea Exploring Expedition. It is due chiefly to him and to his frend Dr. W. B. Carpenter that the British Government, through the influence of the Royal Society, was induced to place at the disposal of -a committee of scientific experts first the small surveying steamer Lightning in 1868, and then the more efficient steamer Porcupine in the two succeeding years, for the purpose of exploring the deep water of the Atlantic from the Faroes in the North to Gibraltar and beyond in the South, in the course of which expeditions they got successful hauls from the then unprecedented depth of 2435 fathoms, nearly three statute miles. It will be remembered that Edward Forbes, from his observations in the Mediterranean (an abnormal sea in some respects), regarded depths of over 300 fathoms as an azoic zone. It was the work of Wyville Thomson and his colleagues Carpenter and Gwyn Jeffreys on these successive dredging expeditions to prove conclusively what was beginning to be suspected by naturalists, that there is no azoic zone in the sea, but that abundant life belonging to many groups of animals extends down to the greatest depths of from four to five thousand fathoms—nearly six statute miles from the surface. These pioneering expeditions in the Lightning and Porcupine— the results of which are not even yet fully made known to science— were epoch-making, inasmuch as they not only opened up this new region to the systematic marine biologist, but gave glimpses of world- wide problems in connection with the physics, the chemistry and the biology of the sea which are only now being adequately investigated by the modern oceanographer. These results, which aroused intense interest amongst the leading scientific men of the time, were so rapidly surpassed and overshadowed by the still greater achievements of the ae PRESIDENT’S ADDRESS, 7 Challenger and other national exploring expeditions that followed in the ’seventies and ’eighties of last century, that there is some danger of their real importance being lost sight of; but it ought never to be forgotten that they first demonstrated the abundance of life of a varied nature in depths formerly supposed to be azoic, and, moreover, that some of the new deep-sea animals obtained were related to extinct forms belonging to the Jurassic, Cretaceous and Tertiary periods. It is interesting to recall that our Association played its part in promoting the movement that led to the Challenger Expedition. Our General Committee at the Edinburgh Meeting of 1871 recom- mended that the President and Council be authorised to co-operate with the Royal Society in promoting ‘a Circumnavigation Expedition, specially fitted out to carry the Physical and Biological Exploration of the Deep Sea into all the Great Oceanic Areas ’; and our Council subse- quently appointed a committee consisting of Dr. Carpenter, Professor Huxley and others to co-operate with the Royal Society in carrying out these objects. It has been said that the Challenger Expedition will rank in history with the voyages of Vasco da Gama, Columbus, Magellan and Cook. Like these it added new regions of the globe to our knowledge, and the wide expanses thus opened up for the first time, the floors of the oceans, though less accessible, are vaster than the discoveries of any previous exploration. Has not the time come for a new Challenger expedition? Sir Wyville Thomson, although leader of the expedition, did not live to see the completed results, and Sir John Murray will be remembered in the history of science as the Challenger naturalist who brought to a successful issue the investigation of the enormous collections and the publication of the scientific results of that memorable voyage: these two Scots share the honour of having guided the destinies of what is still the greatest oceanographic exploration of all times. In addition to taking his part in the general work of the expedition, Murray devoted special attention to three subjects of primary import- ance in the science of the sea, viz.: (1) the plankton or floating life of the oceans, (2) the deposits forming on the sea bottoms, and (8) the origin and mode of formation of coral reefs and islands. It was characteristic of his broad and synthetic outlook on nature that, in place of working at the speciography and anatomy of some group of organisms, however novel, interesting and attractive to the naturalist the deep-sea organisms might seem to be, he took up wide-reaching general problems with economic and geological as well as biological applications. Hach of the three main lines of investigation—deposits, plankton and coral reefs—which Murray undertook on board the Challenger has been most fruitful of results both in his own hands and those of 8 PRESIDENT’S ADDRESS. others: His plankton work has led on to those modern planktonic researches which are closely bound up with the scientific investigation of our sea-fisheries. His work on the deposits accumulating on the floor of the ocean resulted, after years of study in the laboratory as well as in the field, in collaboration with the Abbé Renard of the Brussels Museum, after- wards Professor at Ghent, in the production of the monumental * Deep- Sea Deposits’ volume, one of the Challenger Reports, which first revealed to the scientific world the detailed nature and distribution of the varied submarine deposits of the globe and their relation to the rocks forming the crust of the earth. These studies led, moreover, to one of the romances of science which deeply influenced Murray’s future life and work. In accumu- lating material from all parts of the world and all deep-sea exploring expeditions for comparison with the Challenger series, some ten years later, Murray found that a sample of rock from Christmas Island in the Indian Ocean, which had been sent to him by Commander (now Admiral) Aldrich, of H.M.S. Egeria, was composed of a valuable phosphatic material. This discovery in Murray’s hands gave rise to a profitable commercial undertaking, and he was able to show that some years ago the British Treasury had already received in royalties and taxes from the island considerably more than the total cost of the Challenger Expedition. That first British circumnavigating expedition on the Challenger was followed by other national expeditions (the American Tuscarora and Albatross, the French Travailleur, the German Gauss, National, and Valdivia, the Italian Vettor Pisani, the Dutch Siboga, the Danish Thor and others) and by almost equally cele- brated and important work by unofficial oceanographers such as Alexander Agassiz, Sir John Murray with Dr. Hjort in the Michael Sars, and the Prince of Monaco in his magnificent ocean-going yacht, and by much other good work by many investigators in smaller and humbler vessels. One of these supplementary expeditions I must refer to briefly because of its connection with sea-fisheries. The Triton, under Tizard and Murray, in 1882, while exploring the cold and warm areas of the Faroe Channel separated by the Wyville-Thomson ridge, incidentally discovered the famous Dubh-Artach fishing-grounds, which have been worked by British trawlers ever since. Notwithstanding all this activity during the last forty years since Oceanography became a science, much has still to be investigated in all seas in all branches of the subject. On pursuing any line of investi- gation one very soon comes up against a wall of the unknown or a maze of controversy. Peculiar difficulties surround the subject. The PRESIDENT’S ADDRESS. 9 matters investigated are often remote and almost inaccessible. Unknown factors may enter into every problem. The samples required may be at the other end of a rope or a wire eight or ten miles long, and the oceanographer may have to grope for them literally in the dark and under other difficult conditions which make it uncertain whether his samples when obtained are adequate and representative, and whether they have undergone any change since leaving thew natural environ- ment. It is not surprising then that in the progress of knowledge mistakes have been made and corrected, that views have been held on what seemed good scientific grounds which later on were proved to be erroneous. For example, Edward Forbes, in his division of life in the sea into zones, on what then seemed to be sufficiently good obser- vations in the Algean, but which we now know to be exceptional, placed the limit of life at 300 fathoms, while Wyville Thomson and his fellow- workers on the Porcwpine and the Challenger showed that there is no azoic zone even in the great abysses. Or, again, take the celebrated myth of ‘Bathybius.’ In tthe ‘sixties of last century samples of Atlantic mud, taken when surveying the bottom for the first telegraph cables and preserved in alcohol, were found when examined by Huxley, Haeckel and others to contain what seemed to be an exceedingly primitive protoplasmic organism, which was supposed on good evidence to be widely extended over the floor of the ocean. The discovery of this Bathybius was said to solve the problem of how the deep-sea animals were nourished in the absence of sea- weeds. Here was a widespread protoplasmic meadow upon which other organisms could graze. Belief in Bathybius seemed to be confirmed and established by Wyville Thomson’s results in the Porcupine Expedition of 1869, but was exploded by the naturalists on the Chal- lenger some five years later. Buchanan in his recently published “Accounts Rendered ’ tells us how he and his colleague Murray were keenly on the look-out for hours at a time on all possible occasions for traces of this organism, and how they finally proved, in the spring of 1875 on the voyage between Hong-Kong and Yokohama, that the all-pervading substance like coagulated mucus was an amorphous precipitate of sulphate of lime thrown down from the sea-water in the mud on the addition of a certain proportion of alcohol. He wrote to this effect from Japan to Professor Crum Brown, and it is in evidence that after receiving this letter Crum Brown interested his friends in Edinburgh by showing them how to make Bathybius in the chemical laboratory. Huxley at the Sheffield Meeting of the British Association in 1879 handsomely admitted that he had been mistaken, and it is said that he characterised Bathybius as ‘ not having fulfilled the promise of its youth.’ Will any of our present oceanographic beliefs 10 PRESIDENT’S ADDRESS. share the fate of Bathybius in the future? Some may, but even if they do they may well have been useful steps in the progress of science. Although like Bathybius they may not have fulfilled the promise of their youth, yet, we may add, they will not have lived in the minds of man in vain. Many of the phenomena we encounter in oceanographic investi- gations are so complex, are or may be affected by so many diverse factors, that it is difficult, if indeed possible, to be sure that we are unravelling them aright and that we see the real causes of what we observe. Some few things we know approximately—nothing completely. We know that the greatest depths of the ocean, about six miles, are a little greater than the highest mountains on land, and Sir John Murray has calculated that if all the land were washed down into the sea the whole globe would be covered by an ocean averaging about two miles in depth.° We know the distribution of temperatures and salinities over a great part of the surface and a good deal of the bottom of the oceans, and some of the more important oceanic currents have been charted and their periodic variations, such as those of the Gulf Stream, are being studied. | We know a good deal about the organisms floating or swimming in the surface waters (the epi-plankton), and also those brought up by our dredges and trawls from the bottom in many parts of the world—although every expedition still makes large additions to knowledge. The region that is least known to us, both in its physical conditions and also its inhabitants, is the vast zone of intermediate waters lying between the upper few hundred fathoms and the bottom. That is the region that Alexander Agassiz from his observations with closing tow-nets on the Blake Expedition supposed to be destitute of life, or at least, as modified by his later observations on the Albatross, to be relatively destitute compared with the surface and the bottom, in opposition to the contention of Murray and other oceanographers that an abundant meso-plankton was present, and that certain groups of animals, such as the Challengerida and some kinds of Meduse, were characteristic of these deeper zones. I believe that, as sometimes happens in scientific controversies, both sides were right up to a point, and both could support their views upon observations from particular regions of the ocean under certain circumstances. But much still remains unknown or only imperfectly known even in matters that have long been studied and where practical applications ° It was possibly in such a former world-wide ocean of ionised water that according to the recent speculations of A. H. Church (Zhalassiophyta, 1919) the first living organisms were evolved to become later the floating unicellular plants of the primitive plankton. Ag PRESIDENTS ADDRESS, << ee 11 of great value are obtained—such as the investigation and prediction of tidal phenomena. We are now told that theories require re-inyesti- gation and that published tables are not sufficiently accurate. To take another practical application of oceanographic work, the ultimate causes of variations in the abundance, in the sizes, in the movements and in the qualities of the fishes of our coastal industries are still to seek, and notwithstanding volumes of investigation and a still greater volume of discussion, no man who knows anything of the matter is satisfied with our present knowledge of even the best-known and economically most important of our fishes, such as the Herring, the Cod, the Plaice and the Salmon. Take the case of our common fresh-water eel as an example of how little we know and at the same time of how much has been discovered. All the eels of our streams and lakes of N.-W. Europe live and feed and grow under our eyes without reproducing their kind—no spawning eel has ever been seen. After living for years in immaturity, at last near the end of their lives the large male and female yellow eels undergo a change in appearance and in nature. They acquire a silvery colour and their eyes enlarge, and in this bridal attire they commence the long journey which ends in maturity, reproduction and death. From all the fresh waters they migrate in the autumn to the coast, from the inshore seas to the open ocean and still westward and south to the mid-Atlantic and we know not how much further—for the exact locality and manner of spawning has still to be discovered. The youngest known stages of the Leptocephalus, the larval stage of eels, have been found by the Dane, Dr. Johs. Schmidt, to the west of the Azores where the water is over 2000 fathoms in depth. These _ were about one-third of an inch in length and were probably not long hatched. I cannot now refer to all the able investigators—Grassi, _ Hjort and others—who have discovered and traced the stages of growth _ of the Leptocephalus and its metamorphosis into the ‘ elvers ’ or young eels which are carried by the North Atlantic drift back to the coasts of Europe and ascend our rivers in spring in countless myriads; but no ‘man thas been more indefatigable and successful in the quest than ‘Dr. Schmidt, who in the various expeditions of the Danish Investigation ‘Steamer Thor from 1904 onwards found successively younger and younger stages, and who is during the present summer engaged in a traverse of the Atlantic to the West Indies in the hope of finding the missing link in the chain, the actual spawning fresh-water eel in the intermediate waters somewhere above the abysses of the open ocean.°® ® According to Schmidt’s results the European fresh-water eel, in order to be able to propagate, requires a depth of at least 500 fathoms, a salinity of oe an 35.20 per mille and a temperature of more than 7° C. in the required epth. 12 PRESIDENT’S ADDRESS. Again, take the case of an interesting oceanographic observation which, if established, may be found to explain the variations in time and amount of important fisheries. Otto Pettersson in 1910 discovered by his observations in the Gullmar Fjord the presence of periodic sub- marine waves of deeper salter water in the Kattegat and the fjords of the west coast of Sweden, which draw in with them from the Jutland banks vast shoals of the herrings which congregate there in autumn. The deeper layer consists of ‘bankwater’ of salinity 32 to 34 per | thousand, and as this rolls in along the bottom as a series of huge © undulations it forces out the overlying fresher water, and so the herrings living in the bankwater outside are sucked into the Kattegat and neighbouring fjords and give rise to important local fisheries. Pettersson connects the crests of the submarine waves with the phases of the moon. Two great waves of salter water which reached up to the surface took place in November 1910, one near the time of full moon and the other about new moon, and the latter was at the time when the shoals of herring appeared inshore and provided a profitable fishery. The coincidence of the oceanic phenomena with the lunar phases is not, however, very exact, and doubts have been expressed as to the connection; but if established, and even if found to be due not to the moon but to prevalent winds or the influence of ocean currents, this would be a case of the migration of fishes depending upon mechanical causes, while in other cases it is known that migrations are due to spawning needs or for the purpose of feeding, as in the case of the cod and the herring in the west and north of Norway and in the Barents Sea. Then, turning to a very fundamental matter of purely scientific investigation, we do not know with any certainty what causes the great and all-important seasonal variations in the plankton (or floating minute life of the sea) as seen, for example, in our own home seas, where there is a sudden awakening of microscopic plant life, the Diatoms, in early spring when the water is at its coldest. In the course of a few days the upper layers of the sea may become so filled with organisms that a small silk net towed for a few minutes may capture hundreds of millions of individuals. And these myriads of microscopic forms, after persisting for a few weeks, may disappear as suddenly as they came, to be followed by swarms of Copepoda and many other kinds of minute animals, and these again may give place in the autumn to a second maximum of Diatoms or of the closely related Peridiniales. Of course there are theories as to all these more or less periodic changes in the plankton, such as Liebig’s ‘law of the minimum,’ which limits the production of an organism by the amount of that necessity of existence which is present in least quantity, it may be nitrogen or silicon or 4 PRESIDENTS ADDRESS. 13 phosphorus. According to Raben it is the accumulation of silicie acid in the sea-water that determines the great increase of Diatoms in spring and again in autumn. Some writers have considered these variations in the plankton to be caused largely by changes in temperature supple- mented, according to Ostwald, by the resulting changes in the viscosity of the water; but Murray and others are more probably correct in attributing the spring development of phyto-plankton to the increasing power of the sunlight and its value in photosynthesis. Let us take next the fact—if it be a fact—that the genial warm waters of the tropics support a less abundant plankton than the cold polar seas. The statement has been made and supported by some investigators and disputed by others, both on a certain amount of evi- dence. This is possibly a case like some other scientific controversies where both sides are partly in the right, or right under certain con- ditions. At any rate there are sealed exceptions to the generalisation. The German Plankton Expedition in 1889 showed in its results that much larger hauls of plankton per unit volume of water were obtained in the temperate North and South Atlantic than in the tropics between, and that the warm Sargasso Sea had a remarkably scanty microflora. Other investigators have since reported more or less similar results. Lohmann found the Mediterranean plankton to be less abundant than that of the Baltic, gatherings brought back from tropical seas are fre- quently very scanty, and enormous hauls on the other hand have been recorded from Arctic and Antarctic seas. There is no doubt about the large gatherings obtained in northern waters. I have myself in a few minutes’ haul of a small horizontal net in the North of Norway collected a mass of the large Copepod Calanus finmarchicus sufficient to be cooked and eaten like potted shrimps by half a dozen of the yacht’s company, and I have obtained similar large hauls in the cold Labrador current near Newfoundland. On the other hand, Kofoid and Alexander Agassiz have recorded large hauls of plankton in the Humboldt current off the west coast of America, and during the Challenger Expedition some of the largest quantities of plankton were found in the equatorial Pacific. Moreover, it is common knowledge that on occa- sions vast swarms of some planktonic organism may be seen in tropical waters. The yellow alga Trichodesmium, which is said to have given ts name to the Red Sea and has been familiarly known as ‘ sea-sawdust ’ since the days of Cook’s first voyage,’ may cover the entire surface over considerable areas of the Indian and South Atlantic Oceans; and some elagic animals such as Salpe, Meduse and Ctenophores are also ommonly present in abundance in the tropics. Then, again, American 7 See Journal of Sir Joseph Banks. This and other swarms were also joticed by Darwin during the voyage of the Beagle, 14 PRESIDENT’S ADDRESS. biologists * have pointed out that the warm waters of the West Indies and Florida may be noted for the richness of their floating life for periods of years, while at other times the pelagic organisms become rare and the region is almost a desert sea. It is probable, on the whole, that the distribution and variations of oceanic currents have more than latitude or temperature alone to do with any observed scantiness of tropical plankton. These mighty rivers of the ocean in places teem with animal and plant life, and may sweep abundance of food from one region to another in the open sea. But even if it be a fact that there is this alleged deficiency in tropical plankton there is by no means agreement as to the cause thereof. Brandt first attributed the poverty of the plankton in the tropics to the destruction of nitrates in the sea as a result of the greater intensity of the metabolism of denitrifying bacteria in the warmer water; and various other writers since then have more or less agreed that the presence of these denitrifying bacteria, by keeping down to a minimum the nitrogen concentration in tropical waters, may account for the relative scarcity of the phyto-plankton, and consequently of the ’ zoo-plankton, that has been observed. But Gran, Nathansohn, Murray, Hjort and others have shown that such bacteria are rare or absent in the open sea, that their action must be negligible, and that Brandt’s hypothesis is untenable. It seems clear, moreover, that the plankton does not vary directly with the temperature of the water. Furthermore, Nathansohn has shown the influence of the vertical circulation in the water upon the nourishment of the phyto-plankton—by rising currents bringing up necessary nutrient materials, and especially carbon dioxide from the bottom layers; and also possibly by conveying the products of the drainage of tropical lands to more polar seas so as to maintain the more abundant life in the colder water. Piitter’s view is that the increased metabolism in the warmer water causes all the available food materials to be rapidly used up, and so puts a check to the reproduction of the plankton. According to Van’t Hoff’s law in Chemistry, the rate at which a reaction takes place is increased by raising the temperature, and this probably holds good for all bio-chemical phenomena, and therefore for the metabolism of animals and plants in the sea. This has been verified experimentally in some cases by J. Loeb. The contrast between the plankton of Arctic and Antarctic zones, consisting of large numbers of small Crustaceans belonging to comparatively few species, and that of tropical waters, containing a great many more species generally of smaller size and fewer in number of individuals, is to be ® A. Agassiz, A. G. Mayer, and H, B. Bigelow. PRESIDENT’S ADDRESS. 15 accounted for, according to Sir John Murray and others, by the rate of metabolism in the organisms. ‘The assemblages captured in cold polar waters are of different ages and stages, young and adults of several generations occurring together in profusion,’ and it is supposed that the adults ‘ may be ten, twenty or more years of age.’ At the low temperature the action of putrefactive bacteria and of enzymes is very slow or in abeyance, and the vital actions of the Crustacea take place more slowly and the individual lives are longer. On the other hand, in the warmer waters of the tropics the action of the bacteria is more rapid, metabolism in general is more active, and the various stages in the life-history are passed through more rapidly, so that the smaller organisms of equatorial seas probably only live for days or weeks in place of years. This explanation may account also for the much greater quantity of living organisms which has been found so often on the sea floor in polar waters. It is a curious fact that the development of the polar marine animals is in general ‘ direct’ without larval pelagic stages, the result being that the young settle down on the floor of the ocean in the neighbourhood of the parent forms, so that there come to be enormous congregations of the same kind of animal within a limited area, and the dredge will in a particular haul come up filled with hundreds, it may be, of an Echinoderm, a Sponge, a Crustacean, a Brachiopod, or an Ascidian; whereas in warmer seas the young pass through a pelagic stage and so become more widely distributed over the floor of the ocean. The Challenger Expedition found in the Antarctic certain Echinoderms, for example, which had young in various stages of development attached to some part of the body of the parents, whereas in temperate or tropical regions the same class of animals set free their eggs and the development proceeds in the open water quite independently of, and it may be far distant from, the parent. Another characteristic result of the difference in temperature is that the secretion of carbonate of lime in the form of shells and skeletons proceeds more rapidly in warm than in cold water. The massive shells of molluscs, the vast deposits of carbonate of lime formed by corals and by calcareous seaweeds, are characteristic of the tropics ; whereas in polar seas, while the animals may be large, they are for the most part soft-bodied and destitute of calcareous secretions. The calcareous pelagic Foraminifera are characteristic of tropical and sub-tropical . plankton, and few, if any, are found in polar waters. Globigerina _ * Whether, however, the low temperature may not also retard reproduction is worthy of consideration. 16 PRESIDENT’S ADDRESS. ooze, a calcareous deposit, is abundant in equatorial seas, while in the Antarctic the characteristic deposit is siliceous Diatomaceous ooze. The part played by bacteria in the metabolism of the sea is very important and probably of wide-reaching effect, but we still know very litfle about it. A most promising young Cambridge biologist, the late Mr. G. Harold Drew, now unfortunately lost to science, had already done notable work at Jamaica and at Tortugas, Florida, on the effects produced by a bacillus which is found in the surface waters of these shallow tropical seas and in the mud at the bottom ; and which denitrifies nitrates and nitrites, giving off free nitrogen. He found that this Bacillus calcis also caused the precipitation of soluble calcium salts in the form of calcium carbonate (‘ drewite ’) on a large scale, in the warm shallow waters. Drew’s observations tend to show that the great calcareous deposits of Florida and the Bahamas previously known as ‘coral muds’ are not, as was supposed by Murray and others, derived from broken-up corals, shells, nullipores, &c., but are minute particles of carbonate of lime which have been precipitated by the action of these bacteria.*° The bearing of these observations upon the formation of oolitic limestones and the fine-grained unfossiliferous Lower Paleozoic lime- stones of New York State, recently studied in this connection by R. M. Field,’? must be of peculiar interest to geologists, and forms a notable instance of the annectant character of Oceanography, bringing the metabolism of living organisms in the modern sea into relation with — paleozoic rocks. The work of marine biologists on the plankton has been in the main qualitative, the identification of species, the observation of struc- ture, and the tracing of life-histories. The oceanographer adds to that the quantitative aspect when he attempts to estimate numbers and masses per unit volume of water or of area. Let me lay before you a few thoughts in regard to some such attempts, mainly for the purpose of showing the difficulties of the investigation.. Modern quanti- tative methods owe their origin to the ingenious and laborious work of Victor Hensen, followed by Brandt, Apstein, Lohmann, and others of the Kiel school of quantitative planktologists. We may take their well-known estimations of fish eggs in the North Sea as an example of the method. The floating eggs and embryos of our more important food fishes may occur in quantities in the plankton during certain months in spring, and Hensen and Apstein have made some notable calculations +9 Journ. Mar. Biol. Assoc., October 1911. 1 Carnegie Institute of Washington, Year Book for 1919, p, 197, PRESIDENT’S ADDRESS. 17 based ‘on the occurréncé of these in certain hauls taken at intervals across the North Sea, which led them to the conclusion that, taking six of our most abundant fish, such as the cod and some of the flat fish, the eggs present were probably produced by about 1200 million spawners, enabling them to calculate that the total fish population of the North Sea’ (of these six species), at that time (spring of 1895), amounted to about 10,000 millions. Further calculations led them to the result that the fishermen’s catch of these fishes amounted to about one-quarter of the total population: Now all this is not only of scientific interest, but also of great practical importance if we could be sure that the samples upon which the calculations are based were adequate and representative, but it will be noted that these samples only represent one square metre in 3,465,968,354. Hensen’s state- ment, repeated in various works in slightly differing words, is to the effect that, using a net of which the constants are known hauled vertically through a column of water from a certain depth to the surface, he can calculate the volume of water filtered by the net and so estimate the quantity of plankton under each square metre of the surface; and his whole results depend upon the assumption, which he considers justified, that the plankton is evenly distributed over large areas of water which are under similar conditions. In these calculations in regard to the fish eggs he takes the whole of the North Sea as being an area under similar conditions, but we have known since the days of P. T. Cleve and from the observations of Hensen’s own colleagues that this is not the case, and they have published chart- diagrams showing that at least three different kinds of water under different conditions are found in the North Sea, and that at least five different planktonic areas may be encountered in making a traverse from Germany to the British Isles. If the argument be used that wherever the plankton is found to vary there the conditions cannot be uniform, then few areas of the ocean of any considerable size remain as cases suitable for population-computation from randem samples. It may be doubted whether even the Sargasso Sea, which is an area of more than usually uniform character, has a ‘sufficiently evenly distributed plankton to be treated by Hensen’s method of estimation of the population. In the German Plankton Expedition of 1889 Schiitt reports that in the Sargasso Sea, with its relatively high temperature, the twenty- four catches obtained were uniformly small in quantity. His analysis of the volumes of these catches shows that the average was 3:33 c.c., but the individual catches ranged from 1:5 c.c. to 65 ¢.c., and the diver- gence from the average may be as great as + 3°2'c.c. ; and, after deduct- ing 20 per cent. of the divergence as due to errors of the experiment, 1920 a 18 PRESIDENT’S ADDRESS. Schiitt estimates the mean variation of the plankton at about 16 per cent. above or below. This does not seem to me to indicate the uniformity that might be expected in this ‘ halistatic’’ area occupying the centre of the North Atlantic Gulf Stream circulation. Hensen also made almost simultaneous hauls with the same net in quick succession to test the amount of variation, and found that the average error was about 13 per cent. As so much depends in all work at sea upon the weather, the con- ditions under which the ship is working, and the care taken in the experiment, with the view of getting further evidence under known conditions I carried out some similar experiments at Port Erin on four occasions during last April and on a further occasion a month later, choosing favourable weather and conditions of tide and wind, so as to be able to maintain an approximate position. On each of four days in April the Nansen net, with No. 20 silk, was hauled six times from the same depth (on two occasions 8 fathoms and on -two occasions 20 fathoms), the hauls being taken in rapid succession and the catches being emptied from the net into bottles of 5 per cent. formaline, in which they remained until examined microscopically. The results were of interest, for although they showed considerable uniformity in the amount of the catch——for example, six successive hauls from 8 fathoms being all of them 0:2 c.c. and four out of five from 20 fathoms being 0°6 ¢.c.—the volume was made up rather differently in the successive hauls. The same organisms are present for the most part in each haul, and the chief groups of organisms are present in much the same proportion. For example, in a series where the Copepoda average about 100 the Dinoflagellates average about 300 and the Diatoms about 8000, but the percentage deviation of indi- vidual hauls from the average may be as much as plus or minus 50. The numbers for each organism (about 40) in each of the twenty-six hauls have been worked out, and the details will be published elsewhere, but the conclusion I come to is that if on each occasion one haul only, in place of six, had been taken, and if one had used that haul to estimate the abundance of any one organism in that sea-area, one might have been about 50 per cent. wrong in either direction. Successive improvements and additions to Hensen’s methods in collecting plankton have been made by Lohmann, Apstein, Gran, and others, such as pumping up water of different layers through a hose- pipe and filtering it through felt, filter-paper, and other materials which retain much of the micro-plankton that escapes through the meshes of the finest silk. Use has even been made of the extraordinarily minute and beautifully regular natural filter spun by the pelagic animal Appendicularia for the capture of its own food. This grid-like trap, PRESIDENT’S ADDRESS. 19 when dissected out and examined under the microscope, reveals a surprising assemblage of the smallest protozoa and protophyta, less than 30 micro-millimetres in diameter, which would all pass easily through the meshes of our finest silk nets. The latest refinement in capturing the minutest-known organisms of the plankton (excepting the bacteria) is a culture method devised by Dr. E. J. Allen, Director of the Plymouth Laboratory.’ By diluting half a cubic centimetre of the sea-water with a considerable amount (1500 ¢.c.) of sterilised water treated with a nutrient solution, and distributing that over a large number (70) of small flasks in which after an interval of some days the number of different kinds of organisms which had developed in each flask were counted, he calculates that the sea contains 464,000 of such organisms per litre; and he gives reasons why his cultivations must be regarded as minimum results, ‘and states that the total per litre may well be something like a million. Thus every new method devised seems to multiply many timés the probable total population of the sea. As further results of the quan- titative method it may be recorded that Brandt found about 200 diatoms per drop of water in Kiel Bay, and Hensen estimated that there are several hundred millions of diatoms under each square metre of the North Sea or the Baltic. It has been calculated that there is approxi- mately one Copepod in each cubic inch of Baltic water, and that the annual consumption of these Copepoda by herring is about a thousand billion; and that in the 16 square miles of a certain Baltic fishery there is Copepod food for over 530 millions of herring of an average weight of 60 grammes. There are many other problems of the plankton in addition to quantitative estimates—probably some that we have not yet recognised— and various interesting conclusions may be drawn from recent planktonic observations. Here is a case of the introduction and rapid spread of a form new to British seas. Biddulphia sinensis is an exotic diatom which, according to Osten- feld, made its appearance at the mouth of the Elbe in 1903, and spread during successive years in several directions. It appeared suddenly in our plankton gatherings at Port Erin in November 1909, and has been present in abundance each year since. Ostenfeld, in 1908, when tracing its spread in the North Sea, found that the migration to the north along the coast of Denmark to Norway corresponded with the rate of flow of the Jutland current to the Skagerrak—viz., about 17 cm. per second—a case of plankton distribution throwing light on hydro- graphy—and he predicted that it would soon be found in the English 2 Journ. Mar, Biol. Assoc. xii, 1, July 1919. 20 PRESIDENT’S ADDRESS. Channel. Dr. Marie Lebour, who recently examined the store of plankton gatherings at the Plymouth Laboratory, finds that as a matter of fact this form did appear in abundance in the collections of October 1909, within a month of the time when according to our records it reached Port Erin. Whether or not this is an Indo-Pacific species brought accidentally by a ship from the Far East, or whether it is possibly a new mutation which appeared suddenly in our seas, there is no doubt that it was not present in our Irish Sea plankton gatherings previous to 1909, but has been abundant since that year, and has completely adopted the habits of its English relations—appearing with B. mobiliensis in late autumn, persisting during the winter, reaching a maximum in spring, and dying out before summer. The Nauplius and Cypris stages of Balanus in the plankton form an interesting study. The adult barnacles are present in enormous | abundance on the rocks round the coast, and they reproduce in winter, at the beginning of the year. The newly emitted young are sometimes so abundant as to make the water in the shore pools and in the sea close to shore appear muddy. The Nauplii first appeared at Port Erin, in 1907, in the bay gatherings on February 22 (in 1908 on Feb- ruary 13), and increased with ups and downs to their maximum on April 15, and then decreased until their disappearance on April 26. None were taken at any other time of the year. The Cypris stage follows on after the Nauplius. It was first taken in the bay on April 6, rose to its maximum on the same day with the Nauplii, and was last caught on May 24. Throughout, the Cypris curve keeps below that of the Nauplius, the maxima being 1740 and 10,500 respec- tively. Probably the difference between the two curves represents the death-rate of Balanus during the Nauplius stage. That conclusion I think we are justified in drawing, but I would not venture to use the result of any haul, or the average of a number of hauls, to multiply by the number of square yards in a zone round our coast in order to obtain an estimate of the number of young barnacles, or of the old barnacles that produced them—the irregularities are too great. ; To my mind it seems clear that there must be three factors making for irregularity in the distribution of a plankton organism :— 1. The sequence of stages in its life-history—such as the Nauplius and Cypris stages of Balanus. ; 2. The results of interaction with other organisms—as when a swarm of Calanus is pursued and devoured by a shoal of herring. 3. Abnormalities in time or abundance due to the physical environ- ment—as in favourable or unfavourable seasons. And these factors must be at work in the open ocean as well as in coastal waters. PRESIDENT’S ADDRESSs 21 In many oceanographical inquiries there is a double object. There is the scientific interest and there is the practical utility—the interest, for example, of tracing a particular swarm of a. Copepod like Calanus, and of making out why it is where it is at a particular time, tracing it back to its place of origin, finding that it has come with a particular body of water, and perhaps that it is feeding upon a particular assem- blage of Diatoms ; endeavouring to give a scientific explanation of every stage in its progress. Then there is the utility—the demonstration that the migration of the Calanus has determined the presence of a shoal of herrings or mackerel that are feeding upon it, and so have been brought within the range of the fisherman and have constituted a commercial fishery. We have evidence that pelagic fish which congregate in shoals, such as herring and mackerel, feed upon the Crustacea of the plankton and especially upon Copepoda. A few years ago when the summer herring fishery off the south end of the Isle of Man was unusually near the land, the fishermen found large red patches in the sea where the fish were specially abundant. Some of the red stuff, brought ashore by the men, was examined at the Port Erin Laboratory and found to be swarms of the Copepod Temora longicornis; and the stomachs of the herring caught at the same time were engorged with the same organism. It is not possible to doubt that dnring these weeks of the herring fishery in the Irish Sea the fish were feeding mainly upon this species of Copepod. Some ten years ago Dr. E. J. Allen and Mr. G. E. Bullen published ** some interesting work, from the Plymouth Marine Laboratory, demonstrating the connection between mackerel and Copepoda and sunshine in the English Channel; and Farran' states that in the spring fishery on the West of Ireland the food of the mackerel is mainly composed of Calanus. Then again at the height of the summer mackerel fishery in the Hebrides, in 1913, we found” the fish feeding upon the large Copepod Calanus finmarchicus, which was caught in the tow-net at the rate of about 6000 in a five-minutes’ haul, and 6000 was also the average number found in the stomachs of the fish caught at the same time. These were cases where the fish were feeding upon the organism that was present in swarms—a monotonic plankton—but in other cases the fish are clearly selective in their diet. If the sardine of the French coast can pick out from the micro-plankton the minute Peridiniales in preference to the equally minute Diatoms which are present in the sea at the same time, there seems no reason why the herring and the 18 Journ. Mar. Biol. Assoc. vol. viii. (1909), pp. 394-406. M4 Conseil Internat. Bull, Trimestr, 1902-8, ‘ Planktonique,’ p, 89. 18 * Spolia Runiana,’ iii. Linn. Soc. Journ., Zoology, vol. xxxiv. p. 95, 1918. oo PRESIDENT’S ADDRESS. mackerel should not be able to select particular species of Copepoda or other large organisms from the macro-plankton, and we have evidence that they do. Nearly thirty years ago the late Mr. Isaac Thompson, a constant supporter of the Zoological Section of this Asso- ciation and one of the Honorary Local Secretaries for the last Liver- pool meeting, showed me in 1893 that young plaice at Port Erin were selecting one particular Copepod, a species of Jonesiella, out of many others caught in our tow-nets at the time. H. Blegvad*® showed in 1916 that young food fishes and also small shore fishes pick out certain species of Copepoda (such as Harpacticoids) and catch them individually —either lying in wait or searching for them. A couple of years later *’ Dr. Marie Lebour published a detailed account of her work at Plymouth on the food of young fishes, proving that certain fish undoubtedly do prefer certain planktonic food. These Crustacea of the plankton feed upon smaller and simpler organisms—the Diatoms, the Peridinians, and the Flagellates—and the fish themselves in their youngest post-larval stages are nourished by the same minute forms of the plankton. Thus it appears that our sea- fisheries ultimately depend upon the living plankton which no doubt in its turn is affected by hydrographic conditions. A correlation seems to be established between the Cornish pilchard fisheries and periodic variations in the physical characters (probably the salinity) of the water of the English Channel between Plymouth and Jersey.** Appa- rently a diminished intensity in the Atlantic current corresponds with a diminished fishery in the following summer. Possibly the connection in these cases is through an organism of the plankton. It is only a comparatively small number of different kinds of organisms—both plants and animals—that make up the bulk of the plankton that is of real importance to fish. One ean select about half- a-dozen species of Copepoda which constitute the greater part of the summer zoo-plankton suitable as food for larval or adult fishes, and about the same number of generic types of Diatoms which similarly make up the bulk of the available spring phyto-plankton year after year. This fact gives great economic importance to the attempt to determine with as much precision as possible the times and conditions of occurrence of these dominant factors of the plankton in an average year. An cbvious further extension of this investigation is an inquiry into the degree of coincidence between the times of appearance in the sea of the plankton organisms and of the young fish, and the possible effect of any marked absence of correlation in time and quantity. Just before the war the International Council for the Exploration 6 Rep. Danish Biol. Stat. xxiv. 1916. 17 Journ, Mar. Biol. Assoc. May 1918. 18 See E. C. Jee, Hydrography of the English Channel, 1904-17. PRESIDENT’S ADDRESS. 23 of the Sea’*® arrived at the conclusion that fishery investigations indi- cated the probability that the great periodic fluctuations in the fisheries are connected with the fish larve being developed in great quantities only in certain years. Consequently they advised that plankton work should be directed primarily to the question whether these fluctuations depend upon differences in the plankton production in different years. It was then proposed to begin systematic investigation of the fish larvee and the plankton in spring and to determine more definitely the food of the larval fish at various stages. About the same time Dr. Hjort*® made the interesting suggestion that possibly the great fluctuations in the number of young fish observed from year to year may not depend wholly upon the number of eggs produced, but also upon the relation in time between the hatching of these eggs and the appearance in the water of the enormous quantity of Diatoms and other plant plankton upon which the larval fish after the absorption of their yolk depend for food. He points out that if even a brief interval occurs between the time when the larve first require extraneous nourishment and the period when such food is available, it is highly probable that an enormous mortality would result. In that case even a rich spawning season might yield but a poor result in fish in the commercial fisheries of successive years for some time to come. So that, in fact, the numbers of a year-class may depend not so much upon a favourable spawning season as upon a coincidence between the hatching of the larve and the presence of abundance of phyto-plankton available as food.** The curve for the spring maximum of Diatoms corresponds in a general way with the curve representing the occurrence of pelagic fish eggs in our seas. But is the correspondence sufficiently exact and constant to meet the needs of the case? The phyto-plankton may still be relatively small in amount during February and part of March in some years, and it is not easy to determine exactly when, in the open sea, the fish eggs have hatched out in quantity and the larve have absorbed their food-yolk and started feeding on Diatoms. If, however, we take the case of one important fish—the plaice—we can get some data from our hatching experiments at the Port Erin Biological Station which have now been carried on for a period of seventeen years. An examination of the hatchery records for these years in comparison with the plankton records of the neighbouring sea, which have been kept systematically for the fourteen years from 1907 19 Rapports et Proc. Verb. xix. December 1913. 20 Rapports et Proc. Verb. xx. 1914, p. 204. 21 For the purpose of this argument we may include in ‘ phyto-plankton ’ the various groups of Flagellata and other minute organisms which may be present with the Diatoms, 94 PRESIDENT’S ADDRESS. to 1920 inclusive, shows that in most of these years the Diatoms were present in abundance in the sea a few days at least before the fish larvee from the hatchery were set free, and that it was only in four years (1908, 09, ’18, and ‘14) that there was apparently some risk of the larve: finding no phyto-plankten food, or very little. The evidence so far seems to show that if fish larve are set free in the sea as late as March 20, they are fairly sure of finding suitable food;** but if they are hatched as early as February they run some chance of being starved. But this does not exhaust the risks to the future fishery. C. G. Joh. Petersen and Boysen-Jensen in their valuation of the Limfjord* have shown that in the case not only of some fish but also of the larger invertebrates on which they feed there are marked fluctuations in the number of young produced in different seasons, and that it is only at intervals of years that a really large stock of young is added to the population. The prospects of a year’s fishery may therefore depend primarily upon the rate of spawning of the fish, affected no doubt by hydrographic and other environmental conditions, secondarily upon the presence of a sufficient supply of phyto-plankton in the surface layers of the sea at the time when the fish larve are hatched, and that in its turn depends upon photosynthesis and physico-chemical changes in the water, and finally upon the reproduction of the stock of molluscs or worms at the bottom which constitute the fish food at later stages of growth and development. The question has been raised of recent years—Is there enough plankton in the sea to provide sufficient nourishment for the larger animals, and especially for those fixed forms such as sponges that are supposed to feed by drawing currents of plankton-laden water through the body? Ina series of remarkable papers from 1907 onwards Piitter and his followers put forward the views (1) that the carbon require- ments of such animals could not be met by the amount of plankton in the volume of water that could be passed through the body in a given time, and (2) that sea-water contained a large amount of dis- solved organic carbon compounds which constitute the chief if not the only food of a large number of marine animals. These views have given rise to much controversy and have been useful in stimu- lating further research, but I believe it is now admitted that Piitter’s samples of water from the Bay of Naples and at Kiel were probably polluted, that his figures were erroneous, and that his conclusions 22 All dates and statements as to occurrence refer to the Irish Sea round the south end of the Isle of Man. For further details see Report Lancs. Sea- Fish, Lab. for 1919. 23 Report of Danish Biol. Station for 1919. PRESIDENT’S ADDRESS. 25 must be rejected, or at least greatly modified. His estimates of the plankton were minimum ones, while it seems probable that his figures for the organic carbon present represent a variable amount of organic matter arising from one of the reagents used in the analysis.** The later experimental work of Henze, of Raben, and of Moore shows that the organic carbon dissolved in sea-water is an exceedingly minute quantity, well within the limits of experimental error. Moore puts it, at the most, at one-millionth part, or 1 mgm. ina litre. At the Dundee meeting of the Association in 1912 a discussion on this subject took place, at which Piitter still adhered to a modified form of his hypothesis of the inadequacy of the plankton and the nutrition of lower marine animals by the direct absorption of dissolved organic matter. Further work at Port Erin since has shown that, while the plankton supply as found generally distributed would prove sufficient for the nutrition of such sedentary animals as Sponges and Ascidians, which require ta filter only about fifteen times their own volume of water per hour, it is quite inadequate for active animals such as Crustaceans and Fishes. These latter are, however, able to seek out and capture their food, and are not dependent on what they may filter or absorb from the sea- water. This result accords well with recorded observations on the irregularity in the distribution of the plankton, and with the variations in the occurrence of the migratory fishes which may be regarded as _ following and feeding upon the swarms of planktonic organisms. . This then, like most of the subjects I am dealing with, is still a _ matter of controversy, still not completely understood. Our need, then, is Research, more Research, and still more Research. Our knowledge of the relations bétween plankton productivity and _ variation and the physico-chemical environment is still in its infancy, but gives promise of great results in the hands of the bio-chemist and _ the physical chemist. 4 Recent papers by Sérensen, Palitzsch, Witting, Moore, and others have made clear that the amount of hydrogen-ion concentration as indicated by the relative degree of alkalinity and acidity in the sea- water may undergo local and periodic variations and that these have an. effect upon the living organisms in the water and can be correlated with their presence and abundance. To take an example from our own seas, Professor Benjamin Moore and his assistants in their work at the Port Erin Biological Station in successive years from 1912 onwards have shown** that the sea around the Isle of Man is a good deal more alkaline in spring (say April) than it is in summer (say 24 See Moore, etc., Bio.-Chem. Journ. vi. p. 266, 1912. 4 *5'* Photosynthetic phenomena in sea-water,’ Z'rans. Liverpool Biol. Soc. _ ~XX1xX. 233, 1915. 26 PRESIDENTS ADDRESS. July). The alkalinity, which gets low in summer, increases somewhat in autumn, and then decreases rapidly, to disappear during the winter ; and then once more, after several months of a minimum, begins to come into evidence again in March, and rapidly rises to its maximum in April or May. This periodic change in alkalinity will be seen to correspond roughly with the changes in the living microscopic contents of the sea represented by the phyto-plankton annual curve, and the connection between the two will be seen when we realise that the alkalinity of the sea is due to the relative absence of carbon dioxide. In early spring, then, the developing myriads of diatoms in their metabolic processes gradually use up the store of carbon dioxide accumu- lated during the winter, or derived from the bi-carbonates of calcium and magnesium, and so increase the alkalinity of the water, till the maximum of alkalinity, due to the fixation of the carbon and the reduc- tion in amount of carbon dioxide, corresponds with the crest of the phyto-plankton curve in, say, April. Moore has calculated that the annual turnover in the form of carbon which is used up or converted from the inorganic into an organic form probably amounts to some- thing of the order of 20,000 or 30,000 tons of carbon per cubic mile of sea-water, or, say, over an area of the Irish Sea measuring 16 square miles and a depth of 50 fathoms; and this probably means a production each season of about two tons of dry organic matter, corresponding to at least ten tons of moist vegetation, per acre—which suggests that we may still be very far from getting from our seas anything like the amount of possible food-matters that are produced annually. Testing the alkalinity of the sea-water may therefore be said to be merely ascertaining and measuring the results of the photosynthetic activity of the great phyto-plankton rise in spring due to the daily increase of sunlight. The marine biologists of the Carnegie Institute, Washington, have made a recent contribution to the subject in certain observations on the alkalinity of the sea (as determined by hydrogen-ion concentration), during which they found in tropical mid-Pacific a sudden change to acidity in a current running eastwards. Now in the Atlantic the Gulf Stream, and tropical Atlantic waters generally, are much more alkaline than the colder coastal water running south from the Gulf of St. Lawrence. ‘That is, the colder Arctic water has more carbon dioxide. This suggests that the Pacific easterly set may be due to deeper water, containing more carbon dioxide (=acidity), coming to the surface at that point. The alkalinity of the sea-water can be determined rapidly by mixing the sample with a few drops of an indicator and observing the change of colour; and this method of detecting ocean currents by observing the hydrogen-ion concentration of the water might be useful to navigators as showing the time of entrance to a known current. — Er PRESIDENT’S ADDRESS. 27 Oceanography has many practical applications—chiefly, but by no means wholly, on the biological side. The great fishing industries of the world deal with living organisms, of which all the vital activities and the inter-relations with the environment are matters of scientific investigation. Adquiculture is as susceptible of scientific treatment as agriculture can be; and the fisherman who has been in the past too much the nomad and the hunter—if not, indeed, the devastating raider— must become in the future the settled farmer of the sea if his harvest is to be less precarious. Perhaps the nearest approach to cultivation of a marine product, and of the fisherman reaping what he has actually sown, is seen in the case of the oyster and mussel industries on the west coast of France, in Holland, America, and to a less extent on our own coast. Much jas been done by scientific men for these and other similar coastal fisheries since the days when Professor Coste in France in 1859 introduced oysters from the Scottish oyster-beds to start the great industry at Arcachon and elsewhere. Now we buy back the descendants of our own oysters from the French ostreicul- turists to replenish our depleted beds. It is no small matter to have introduced a new and important food- fish to the markets of the world. The remarkable deep-water ‘tile- fish,’ new to science and described as Lopholatilus chameleonticeps, was discovered in 1879 by one of the United States fishing schooners to the south of Nantucket, near the 100-fathom line. Several thousand pounds weight were caught, and the matter was duly investigated by the United States Fish Commission. For a couple of years after that the fish was brought to market in quantity, and then something unusual happened at the bottom of the sea, and in 1882 millions of dead tile- fish were found floating on the surface over an area of thousands of square miles. The schooner Navarino sailed for two days and a night through at least 150 miles of sea, thickly covered as far as the eye could reach with dead fish, estimated at 256,000 to the square mile. The Fish Commission sent a vessel to fish systematically over the grounds known as the ‘ Gulf Stream slope,’ where the tile-fish had been so abundant during the two previous years, but she did not catch a single fish, and the associated sub-tropical invertebrate fauna was also practically obliterated. This wholesale destruction was attributed by the American oceano- graphers to a sudden change in the temperature of the water at the bottom, due in all probability to a withdrawal southwards of the warm Gulf Stream water and a flooding of the area by the cold Labrador current. I am indebted to Dr. C. H. Townsend, Director of the celebrated New York Aquarium, for the latest information in regard to the 98 PRESIDENT’S ADDRESS. yeappearance in quantity of this valuable fish upon the old fishing grounds off Nantucket and Long Island, at about 100 miles from the coast to the east and south-east of New York. It is believed that the tile-fish is now abundant enough to maintain an important fishery, which will add an excellent food-fish to the markets of the United States. It is easily caught with lines at all seasons of the year, and reaches a length of over three feet and a weight of 40 to 50 pounds. During July 1915 the product of the fishery was about two and a half million pounds weight, valued at 55,000 dollars, and in the first few months of 1917 the catch was four and a half million pounds, for which the fishermen received 247,000 dollars. We can scarcely hope in European seas to add new food-fishes to our markets, but much may be done through the qp-operation of scientific investigators of the ocean with the Administrative Departments to bring: about a more rational conservation and exploitation of the national fisheries. Earlier in this address I referred to the pioneer work of the dis- tinguished Manx naturalist, Professor Edward Forbes. There are many of his writings and of his lectures which I have no space to refer to which have points of oceanographic interest. Take this, for example, in reference to our national sea fisheries. We find him in 1847 writing to a friend: ‘ On Friday night I lectured at the Royal Institution. The subject was the bearing of submarine researches and distribution matters on the fishery question. I pitched into Govern- ment mismanagement pretty strong, and made a fair case of it. It seems to me that at a time when half the country is starving we are utterly neglecting or grossly mismanaging great sources of wealth and food. . . . Were I arich man I would make the subject a hobby, for the good of the country and for the better proving that the true interests of Government are those linked with and inseparable from Science.’ We must still cordially approve of these last words, while recognising that our Government Department of Fisheries is now being organised on better lines, is itself carrying on scientific work of national importance, and is, I am happy to think, in complete sympathy with the work of independent scientific investigators of the sea and desirous of closer co-operation with University laboratories and _ biological stations. During recent years one of the most important and most frequently discussed of applications of fisheries investigation has been the pro- ductivity of the trawling grounds, and especially those of the North Sea. It has been generally agreed that the enormous increase of fishing power during the last forty years or so has reduced the number of large plaice, so that the average size of that fish caught in our home = PRESIDENT’S ADDRESS. 29 waters has become smaller, although the total number of plaice landed had continued to increase up to the year of the outbreak of war. Since then, from 1914 to 1919, there has of necessity been what may be described as the most gigantic experiment ever seen in the closing of extensive fishing grounds. It is still too early to say with any certainty exactly what the results of that experiment have been, although some indications of an increase of the fish population in certain areas have been recorded. For example, the Danes, A. C. J ohansen and Kirstine Smith, find that large plaice landed in Denmark are now more abun- dant, and they attribute this to a reversal of the pre-war tendency, due to less intensive fishing. But Dr. James Johnstone has pointed out that there is some evidence of a natural periodicity in abundance of such fish and that the results noticed may represent phases in a cyclic change. If the periodicity noted in Liverpool Bay*® holds good for other grounds it will be necessary in.any comparison of pre-war and post- war statistics to take this natural variation in abundance into very careful consideration. In the application of oceanographic investigations to sea-fisheries problems, one ultimate aim, whether frankly admitted or not, must be to obtain some kind of a rough approximation to a census or valua- tion of the sea—of the fishes that form the food of man, of the lower animals of the sea-bottom on which many of the fishes feed, and of the planktonic contents of the upper waters which form the ultimate organised food of the sea—and many attempts have been made in different ways to attain the desired end. Our knowledge of the number of animals living in different regions of the sea is for the most part relative only. We know that one haul of the dredge is larger than another, or that one locality seems richer than another, but we have very little information as to the actual numbers of any kind of animal per square foot or per acre in the sea. Hensen, as we have seen, attempted to estimate the number of food- fishes in the North Sea from the number of their eggs caught im a comparatively small series of hauls of the tow-net, but the data were probably quite insufficient and the conclusions may be erroneous. It is an interesting speculation to which we cannot attach any economic importance. Heincke says of it: ‘This method appears theoretically feasible, but presents in practice so many serious difficulties that no positive results of real value have as yet been obtained.’ All biologists must agree that to determine even approximately the number of individuals of any particular species living in a known area is a contribution to knowledge which may be of great economic value 26 See Johnstone, Report Lancs. Sea-Fish Lab; for 1917, p. 60; and Daniel, Report for 1919, p. 51. 30 PRESIDENT’S ADDRESS. aac in the case of the edible fishes, but it may be doubted whether Hensen’s methods, even with greatly increased data, will ever give us the required information. Petersen’s method, of setting free marked plaice and then assuming that the proportion of these recaught is to the total number marked as the fishermen’s catch in the same district is to the total population, will only hold good in circumscribed areas where there is practically no migration and where the fish are fairly evenly dis- tributed. This method gives us what has been called ‘the fishing coefficient,’ and this has been estimated for the North Sea to have a probable value of about 0°33 for those sizes of fish which are caught by the trawl. Heincke,*’ from an actual examination of samples of the stock on the ground obtained by experimental trawling (‘ the catch coefficient ’), supplemented by the market returns of the various countries, estimates the adult plaice at about 1,500 millions, of which about 500 millions are caught or destroyed by the fishermen annually. It is difficult to imagine any further method which will enable us to estimate any such case as, say, the number of plaice in the North Sea where the individuals are so far beyond our direct observation and are liable to change their positions at any moment. But a beginning can be made on more accessible ground with more sedentary animals, and Dr. C. G. Joh. Petersen, of the Danish Biological Station, has for some years been pursuing the subject in a series of interesting Reports on the ‘ Evaluation of the Sea.’?* He uses a bottom-sampler, or grab, which can be lowered down open and then closed on the bottom so as to bring up a sample square foot or square metre (or in deep water one-tenth of a square metre) of the sand or mud and its inhabitants. With this apparatus, modified in size and weight for different depths and bottoms, Petersen and his fellow-workers have made a very thorough examination of the Danish waters, and especially of the Kattegat and the Limfjord, have described a series of ‘ animal communities ’ characteristic of different zones and regions of shallow water, and have arrived at certain numerical results as to the quantity of animals in the Kattegat expressed in tons—such as 5,000 tons of plaice requiring as food 50,000 tons of ‘ useful animals’ (mollusca and polychaet worms), and 25,000 tons of starfish using up 200,000 tons of useful animals which might otherwise serve as food for fishes, and the dependence of all these animals directly or indirectly upon the great beds of Zostera, which make up 24,000,000 tons in the Kattegat. Such estimates are obviously of great biological interest, and even if only rough approximations are a valuable contribution to our under- *7 F. Heincke, Oons. Per. Internat. Explor. de la Mer, ‘Investigations on the Plaice,’ Copenhagen, 1913. 28 See Reports of the Danish Biological Station, and especially the Report for 1918 ‘ The Sea Bottom and its Production of Fish Food,’ E a PRESIDENT’S ADDRESS, 31 standing of the metabolism of the sea and of the possibility of increasing the yield of local fisheries. But on studying these Danish results in the light of what we know of our own marine fauna, although none of our seas have been examined in the same detail by the bottom-sampler method, it seems probable that the animal communities as defined by Petersen are not exactly applicable on our coasts and that the estimates of relative and absolute abundance may be very different in different seas under different conditions. The work will have to be done in each great area, such as the North Sea, the English Channel, and the Irish Sea, independently. This is a necessary _ investigation, both biological and physical, which lies before the oceano- graphers of the future, upon the results of which the future preservation and further cultivation of our national sea-fisheries may depend. : It has been shown by Johnstone and others that the common edible animals of the shore may exist in such abundance that an area of the sea may be more productive of food for man than a similar area of _ pasture or crops on land. A Lancashire mussel bed has been shown to have as many as 16,000 young mussels per square foot, and it is estimated that in the shallow waters of Liverpool Bay there are from twenty to 200 animals of sizes varying from an amphipod to a plaice on each square metre of the bottom.”* From these and similar data which can be readily obtained, it is not difficult to calculate totals by estimating the number of square _ yards in areas of similar character between tide-marks or in shallow water. And from weighings of samples some approximation to the number of tons of available food may be computed. But one must not go too far. Let all the figures be based upon actual observation. _ Imagination is necessary in science, but in calculating a population ; of even a very limited area it is best to believe only what one can see and measure. Countings and weighings, however, do not give us all the informa- tion we need. It is something to know even approximately the number of millions of animals on a mile of shore and the number of millions of tons of possible food in a sea-area, but that is not sufficient. All food-fishes are not equally nourishing to man, and all plankton and bottom invertebrata are not equally nourishing to a fish. At this point the biologist requires the assistance of the physiologist and the bio-chemist. We want to know next the value of our food matters in proteids, carbohydrates, and fats, and the resulting calories. Dr. Johnstone, of the Oceanography Department of the University of Liverpool, has already shown us how markedly a fat summer herring — 29 Conditions of Life in the Sea, Cambridge Univ. Press. 1908. 32 PRESIDENT’S ADDRESS. differs in essential constitution from the ordinary white fish, euck.; as the cod, which is almost destitute of fat. Professor Brandt, at Kiel, Professor Benjamin Moore, at Port Erin, and others have similarly shown that plankton gatherings may vary greatly in their nutrient value according as they are composed mainly of Diatoms, of Dinoflagellates, or of Copepoda. And, no doubt, the animals of the ‘ benthos,’ the common invertebrates of our shores, will show similar differences in analysis.*° It is obvious that some contain more solid flesh, others more water in their tissues, others more calcareous matter in the exoskeleton, and that therefore weight for weight we may be sure that some are more nutritious than the others ; and this is probably at least one cause of that preference we see in some of our bottom-feeding fish for certain kinds of food, such as polychaet worms, in which there is relatively little waste, and thin- shelled lamellibranch molluscs, such as young mussels, which have a highly nutrient body in a comparatively thin and brittle shell. My object in referring to these still incomplete investigations is to direct attention to what seems a natural and useful extension of faunistic work, for the purpose of obtaining some approximation to a quantitative estimate of the more important animals of our shores and shallow water and their relative values as either the immediate or the ultimate food of marketable fishes. Each such fish has its ‘ food-chain’ or series of alternative chains, leading back from the food of man to the invertebrates upon which it preys and then to the food of these, and so down to the smallest and simplest organisms in the sea, and each such chain must have all its links fully worked out as to seasonal and quantitative occurrence back to the Diatoms and Flagellates which depend upon physical con- ditions and take us beyond the range of biology—but not beyond that of oceanography. The Diatoms and the Flagellates are probably more important than the more obvious sea-weedg not only as food, but also in supplying to the water the oxygen necessary for the respiration of living protoplasm. Our object must be to estimate the rate of pro- duction and rate of destruction of all organic substances in the sea. To attain to an approximate census and valuation of the sea— remote though it may seem—is a great aim, but it is not sufficient. We want not only to observe and to count natural objects, but also to understand them. We require to know not merely what an organism is—in the fullest detail of structure and development and affinities— 80 Moore and others have made analyses of the protein, fat, etc., in the soft parts of Sponge, Ascidian, Aplysia, Fusus, Echinus and Cancer at Port Erin, and find considerable differences—the protein ranging, for example, from 8 to 51 per cent., and the fat from 2 to 14 per cent. (see Bio-Chemical Journ. vi. p. 291). PRESIDENT’S ADDRESS. 33 and also where it occurs—again in full detail—and in what abundance under different circumstances, but also how it lives and what all its relations are to both its physical and its biological environment, and that is where the physiologist, and especially the bio-chemist, can help us. In the best interests of biological progress the day of the naturalist who merely collects, the day of the anatomist and histologist who merely describe, is over, and the future is with the observer and the experimenter animated by a divine curiosity to enter into the life of the organism and understand how it lives and moves and has its being. ‘ Happy indeed is he path has been able to discover the causes of things.’ Cardiff is a sea-port, and a great sea-port, and the Bristol Channel is a notable sea-fisheries centre of growing importance. The explorers and merchant venturers of the South-West of England are celebrated in history. What are you doing now in Cardiff to advance our knowledge of the ocean? You have here an important university centre and a great modern national museum, and either or both of these homes of research might do well to establish an oceanographical department, which would be an added glory to your city and of practical utility to the country. This is the obvious centre in Wales for a sea-fisheries institute for both research and education. Many important local move- ments have arisen from British Association meetings, and if such a notable scientific development were to result from the Cardiff meeting of 1920, all who value the advance of knowledge and the application of science to industry would applaud your enlightened action. But in a wider sense, it is not to the people of Cardiff alone that I appeal, but to the whole population of these Islands, a maritime people who owe everything to the sea. I urge them to become better informed in regard to our national sea-fisheries and take a more enlightened interest in the basal principles that underlie a rational regulation and exploitation of these important industries. National efficiency depends to a very great extent upon the degree in which scientific results and methods are appreciated by the people and scientific investigation is promoted by the Government and other administrative authorities. The principles and discoveries of science apply to aquiculture no less than to agriculture. To increase the harvest of the sea the fisheries must be continuously investigated, and such cultivation as is possible must be applied, and all this is clearly a natural application of the biological and hydrographical work now united under the science of Oceanography. 1920 D SECTION A: CARDIFF, 1920. ADDRESS MATHEMATICAL AND PHYSICAL SCIENCE SECTION BY Proressor A. 8. EDDINGTON, M.A., M.8c., F.B.S., PRESIDENT OF THE SECTION. The Internal Constitution of the Stars. Last year at Bournemouth we listened to a proposal from the President of the Association to bore a hole in the crust of the earth and discover the conditions deep down below the surface. This proposal may remind us that the most secret places of Nature are, perhaps, not 10 to the n-th miles above our heads, but 10 miles below our feet. In the last five years the outward march of astronomical discovery has been rapid, and the most remote worlds are now scarcely safe from its inquisition. By the work of H. Shapley the globular clusters, which are found to be at distances scarcely dreamt of hitherto, have been explored, and our knowledge of them is in some respects more com- plete than that of the local aggregation of stars which includes the Sun. Distance lends not enchantment but precision to the view. Moreover, theoretical researches of Hinstein and Weyl make it probable that the space which remains beyond is not illimitable; not merely the material universe, but space itself, is perhaps finite; and the explorer must one day stay his conquering march for lack of fresh realms to invade. But to-day let us turn our thoughts inwards to that other region of mystery—a region cut off by more substantial barriers, for, contrary to many anticipations, even the discovery of the fourth dimension has not enabled us to get at the inside of a body. Science has material and non-material appliances to bore into the interior, and I have chosen to devote this address to what may be described as analytical boring devices—absit omen! The analytical appliance is delicate at present, and, I fear, would make little headway. against the solid crust of the earth. Instead of letting it blunt itself against the rocks, let us look round for something easier to penetrate. The Sun? Well, perhaps. Many have struggled to penetrate the mystery of the interior of the Sun; but the difficulties are great, for its substance is denser than water. It may not be quite so bad as Biron makes out in Love’s Labour’s Lost: — | The heaven’s glorious sun, That will not be deep-searched with saucy looks; Small have continual plodders ever won Save base authority from others’ books. ¢ i ( A.—MATHEMATIUS AND PHYSICS. 35 But it is far better if we can deal with matter in that state. known as a perfect gas, which charms away difficulties as by magic... Where shall it be found? . is A few years ago we should have been puzzled to say where, except perhaps in certain nebula; but now it is known that abundant material of this kind awaits investigation. Stars in a truly gaseous state exist in great numbers, although at first sight they are scarcely to be dis- criminated from dense stars like our Sun. Not only so, but the gaseous stars are the most powerful light-givers, so that they force themselves on our attention. Many of the familiar stars are of this kind—Aldebaran, Canopus, Arcturus, Antares; and it would be safe to say that three-quarters of the naked-eye stars are in this diffuse state. This remarkable condition has been made known through the researches of H. N. Russell! and E. Hertzsprung; the way.in which their conclusions, which ran counter to the prevailing thought of the time, have been substantiated on all sides by overwhelming evidence, is the outstanding feature of recent progress in stellar astronomy. _ The diffuse gaseous stars are called giants, and the dense stars are ealled dwarfs. During the life of a star there is presumably a gradual merease of density through contraction, so that these terms distinguish the earlier and later stages of stellar history.. It appears that a star begins its effective life as.a giant of comparatively low temperature— a red or M-type star. As this diffuse mass of gas contracts its tem- perature must rise, a conclusion long ago pointed out by Homer Lane. The rise continues until the star becomes too dense, and ceases to behave as a perfect gas. A maximum temperature is attained, depend- ing on the mass, after which the star, which has now become a dwarf, cools and further contracts. Thus each temperature-level is passed through twice, once in an ascending and once in a descending stage— once as a giant, once as a dwarf. ‘Temperature plays so predominant a part in the usual spectral classification that the ascending and descending stars were not originally discriminated, and the customary. classification led to some perplexities. The separation of the two series was discovered through their great difference in luminosity, particularly striking in the case of the red and yellow stars, where the two stages fall widely apart in the star’s history. The bloated giant has a far larger surface than the compact dwarf, and gives correspondingly greater light. The distinction was also revealed by direct determina- tions of stellar densities, which are possible in the case of. eclipsing variables like Algol. Finally, Adams and Kohlschiitter have set the seal on this discussion by showing that there are actual spectral differ- ences between the ascending and descending stars at the same tem- aie which are conspicuous enough—when they are looked or. ‘Perhaps we should not too hastily assume that the direction of evolution is necessarily in the order of increasing density, in view of our ignorance of the origin of a star’s heat, to which I must allude later. But, at any rate, it is a great advance to have disentangled what ~ ! Nature, vol. 93, pp. 227, 252, 281. D2 36 SECTIONAL ADDRESSES. is the true order of continuous increase of density, which was hidden by superficial resemblances. The giant stars, representing the first half of a star’s life, are taken as material for our first boring experiment. Probably, measured in time, this stage corresponds to much less than half the life, for here it is the ascent which is easy and the way down is long and slow. Let us try to picture the conditions inside a giant star. We need not dwell on the vast dimensions—a mass like that of the Sun, but swollen to much greater volume on account of the low density, often below that of our own atmosphere. It is the star as a storehouse of heat which especially engages our attention. In the hot bodies familiar to us the heat consists in the energy of motion of the ultimate particles, flying at great speeds hither and thither. So too in the stars a great store of heat exists in this form; but a new feature arises. A large proportion, sometimes more than half the total heat, consists of imprisoned radiant energy—ether-waves travelling in all directions trying to break through the material which encages them. The star is like a sieve, which can only retain them temporarily ; they are turned aside, scattered, absorbed for a moment, and flung out again in a new direction. An element of energy may thread the maze for hundreds of years before it attains the freedom of outer space. Nevertheless the sieve leaks, and a steady stream permeates outwards, supplying the light and heat which the star radiates all round. That some ethereal heat as well as material heat exists in any hot body would naturally be admitted; but the point on which we have here to lay stress is that in the stars, particularly in the giant stars, the ethereal portion rises to an importance which quite transcends our ordinary experience, so that we are confronted with a new type of problem. In a red-hot mass of iron the ethereal energy constitutes less than a billionth part of the whole; but in the tussle between matter and ether the ether gains a larger and larger proportion of the energy as the temperature rises. This change in proportion is rapid, the ethereal energy increasing rigorously as the fourth power of the tem- perature, and the material energy roughly as the first power. But even at the temperature of some millions of degrees attained inside the stars there would still remain a great disproportion; and it is the low density of material, and accordingly reduced material energy per unit volume in the giant stars, which wipes out the last few powers of 10. In all the giant stars known to us, widely as they differ from one another, the conditions are just reached at which these two varieties of heat-energy have attained a rough equality; at any rate one cannot be neglected compared with the other. Theoretically there could be conditions in which the disproportion was reversed and the ethereal far out-weighed the material energy; but we do not find them in the stars. It is as though the stars had been measured out—that their sizes had been determined—with a view to this balance of power; and one cannot refrain from attributing to this condition a deep significance in the evolution of the cosmos into separate stars. To recapitulate. We are acquainted with heat in two forms—the energy of motion of material atoms and the energy of ether waves. In OE ——— A.—MATHEMATICS AND PHYSICS. 37 familiar hot bodies the second form exists only in insignificant quanti- ties. In the giant stars the two forms are present in more or less equal proportions. That is the new feature of the problem. On account of this new aspect of the problem the first attempts to penetrate the interior of a star are now seen to need correction. In saying this we do not depreciate the great importance of the early researches of Lane, Ritter, Emden, and others, which not only pointed the way for us to follow, but achieved conclusions of permanent value. One of the first questions they had to consider was by what means the heat radiated into space was brought up to the surface from the low level where it was stored. They imagined a bodily transfer of the hot material to the surface by currents of convection, as in our own atmosphere. But actually the problem is, not how the heat can be brought to the surface, but how the heat in the interior can be held back sufficiently—how it can be barred in and the leakage reduced to the comparatively small radiation emitted by the stars. Smaller bodies have to manufacture the radiant heat which they emit, living from hand to mouth; the giant stars merely leak radiant heat from their store. I have put that much too crudely; but perhaps it suggests the general idea. The recognition of ethereal energy necessitates a twofold modifi- cation in the calculations. In the first place, it abolishes the supposed convection currents; and the type of equilibrium is that known as radiative instead of convective. This change was first suggested by R. A. Sampson so long ago as 1894. The detailed theory of radiative equilibrium is particularly associated with K. Schwarzschild, who applied it to the Sun’s atmosphere. It is perhaps still uncertain whether it holds strictly for the atmospheric layers, but the arguments for its validity in the interior of a star are far more cogent. Secondly, the outflowing stream of ethereal energy is powerful enough to exert a direct mechanical effect on the equilibrium of a star. It is as though a strong wind were rushing outwards. In fact we may fairly say that the stream of radiant energy is a wind; for though ether waves are not usually classed as material, they have the chief mechanical properties of matter, viz. mass and momentum. This wind distends the star and relieves the pressure on the inner parts. The pressure on the gas in the interior is not the full weight of the superincumbent columns, because that weight is partially borne by the force of the escaping ether waves beating their way out. This force of radiation-pressure, as it is called, makes an important difference in the formulation of the conditions for equilibrium of a star. Having revised the theoretical investigations in accordance with these considerations,? we are in a position to deduce some definite numerical results. On the observational side we have fairly satis- factory knowledge of the masses and densities of the stars and of the total radiation emitted by them; this knowledge is partly individual and partly statistical. The theoretical analysis connects these observational data on the one hand with the physical properties of the material inside 2 Astrophysical Journal, vol. 48, p. 205. 38 SECTIONAL ADDRESSES. the star on the other hand. We can thus find certain information as to the inner material, as though we had actually bored a hole. So far as can be judged there are only two physical properties of the material which can concern us—always provided that it is sufficiently rarefied to behave as a perfect gas—viz. the average molecular weight and the transparency or permeability to radiant energy. In connecting these two unknowns with the quantities given directly by astronomical observation we depend entirely on the well-tried principles of conserva- tion of momentum and the second law of thermodynamics. If any element of speculation remains in this method of investigation, I think it is no more than is inseparable from every kind of theoretical-advance. We have, then, on the one side the mass, density and output of heat, quantities as to which we have observational knowledge; on the other side, molecular weight and transparency, quantities which we want to discover. To find the transparency of stellar material to the radiation traversing it, is of particular interest because it links on this astronomical inquiry to physical investigations now being carried on in the laboratory, and to some extent it extends those investigations to conditions unattainable on the earth. At high temperatures the ether waves are mainly of very short wave-length, and in the stars we are dealing mainly with radiation of wave-length 3 to 30 Angstrém units, which might be described as very soft x-rays. It is interesting, therefore, to compare the results with the absorption of the harder a-rays dealt with by physicists. To obtain an exact measure of this absorption in the stars we have to assume a value of the molecular weight; but fortunately the extreme range possible for the molecular weight gives fairly narrow limits for the absorption. The average weight of the ultimate independent particles in a star is probably rather low, because in the conditions prevailing there the atoms would be strongly ionised; that is to say, many of the outer electrons of the system of the atom would be broken off; and as each of these free electrons counts as an independent molecule for the present purposes, this brings down the average weight. In the extreme case (probably not reached in a star) when the whole of the electrons outside the nucleus are detached the average weight comes down to about 2, whatever the material, because the number of electrons is about half the atomic weight for all the elements (except hydrogen). We may, then, safely take 2 as the extreme lower limit. For an upper limit we might perhaps take 200; but to avoid controversy we shall be generous and merely assume that the molecular weight is not greater than— infinity. Here is the result :— For molecular weight 2, mass-coefficient of absorption=10 ©.G.8. units. For molecular weight co , mass-coefficient of absorption =130 C.G.§. units. The true value, then, must be between 10 and 130. Partly from thermodynamical considerations, and partly from further comparisons of astronomical observation with theory, the most likely value seems to be about 35 C.G.S. units, corresponding to molecular weight 3°5. Dll it i ee a A.—MATHEMATICS AND PHYSICS. 39 Now this is of the same order of magnitude as the absorption of a@-rays measured in the laboratory. I think the result is in itself of some interest, that in such widely different investigations we should approach the same kind of value of the opacity of matter to radiation. The penetrating power of the radiation in the star is much like that of x-rays; more than half is absorbed in a path of 20 cms. at atmospheric density. Incidentally, this very high opacity explains why a star is so nearly heat tight, and can store vast supplies of heat with comparatively little leakage. So far this agrees with what might have been anticipated; but there is another conclusion which physicists would probably not have foreseen. The giant series comprises stars differing widely in their densities and temperatures, those at one end of the series being on the average about ten times hotter throughout than those at the other end. By the present investigation we can compare directly the opacity of the hottest stars with that of the coolest stars. The rather surprising result emerges that the opacity is the same for all; at any rate there is no difference large enough for us to detect. There seems no room for doubt that at these high temperatures the absorption-coefficient is approaching a limiting value, so that over a wide range it remains practically constant. With regard to this constancy, it is to be noted that the temperature is concerned twice over: it determines the character and wave-length of the radiation to be absorbed, as well as the physical condition of the material which is absorbing. From the experimental knowledge of x-rays we should have expected the absorption to vary very rapidly with the wave length, and therefore with the temperature. it is surprising, therefore, to find a nearly constant value. The result becomes a little less mysterious when we consider more closely the nature of absorption. Absorption is not a continuous process, and after an atom has absorbed its quantum it is put out of action for a ‘time until it can recover its original state. We know very little of what determines the rate of recovery of the atom, but it seems clear that there is a limit to the amount of absorption that can be performed by an atom in a given time. When that limit is reached no increase in the intensity of the incident radiation will lead to any more absorption. There is in fact a saturation effect. In the laboratory experiments the radiation used is extremely weak; the atom is practically never caught unprepared, and the absorption is propor- tional to the incident radiation. But in the stars the radiation is very intense and the saturation effect comes in. Even granting that the problem of absorption in the stars involves this saturation effect, which does not affect laboratory experiments, it is not very easy to understand theoretically how the various conditions combine to give a constant absorption-coefficient independent of tem- perature and wave-length. But the astronomical results seem con- clusive. Perhaps the most hopeful suggestion is one made to me a few years ago by C. G. Barkla. He suggested that the opacity of the stars may depend mainly on scattering rather than on true atomic absorption. In that case the constancy has a simple explanation, for it is known that the coefficient of scattering (unlike true absorption) 40 SECTIONAL ADDRESSES. approaches a definite constant value for radiation of short wave-length. The value, moreover, is independent of the material. Further, scat- tering is a continuous process, and there is no likelihood of any saturation effect; thus for very intense streams of radiation its value is maintained, whilst the true absorption may sink to comparative insignificance. The difficulty in this suggestion is a numerical dis- crepancy between the known theoretical scattering and the values already given as deduced from the stars. The theoretical coefficient is only 0°2 compared with the observed value 10 to 130. SBarkla further pointed out that the waves here concerned are not short enough to give the ideal coefficient ; they would be scattered more powerfully, because under their influence the electrons in any atom would all vibrate in the same phase instead of haphazard phases. This might help to bridge the gap, but not sufficiently. It must be remembered that many of the electrons have broken loose from the atom and do not contribute to the increase.* Making all allowances for uncertainties in the data, it seems clear that the astronomical opacity is definitely higher than the theoretical scattering. Very recently, however, a new possibility has opened up which may possibly effect a reconciliation. Later in the address I shall refer to it again. Astronomers must watch with deep interest the investigations of these short waves, which are being pursued in the laboratory, as well as the study of the conditions of ionisation both by experimental and theoretical physics, and I am glad of this opportunity of bringing before iheke who deal with these problems the astronomical bearing of their work. I can only allude very briefly to the purely astronomical results which follow from this investigation ;* it is here that the best oppor- tunity occurs for checking the theory by comparison with observation, and for finding out in what respects it may be deficient. Unfortunately, the observational data are generally not very precise, and the test is not so stringent as we could wish. It turns out that (the opacity being constant) the total radiation of a giant star should be a function of its mass only, independent of its temperature or state of diffuseness. The total radiation (which is measured roughly by the luminosity) of any one star thus remains constant during the whole giant stage of its history. This agrees with the fundamental feature, pointed out by Russell in introducing the giant and dwarf hypothesis, that giant stars of every spectral type have nearly the same luminosity. From the range of luminosity of these stars it is now possible to find their range of mass. The masses are remarkably alike—a fact already suggested by work on double stars. Limits of mass in the ratio 3: 1 would cover the great majority of the giant stars. Somewhat tentatively we are able to extend the investigation to dwarf stars, taking account of the 3 E.g., for iron non-ionised the theoretical scattering is 5.2, against an astronomical value 120. If 16 electrons (2 rings) are broken off the theoretical coefficient is 0.9 against an astronomical value 35. For different assumptions as to ionisation the values chase one another, but cannot be brought within reasonable range. 4 Monthly Notices, vol. 77, pp. 16, 596; vol. 79, p. 2. A.—MATHEMATICS AND PHYSICS. 41 deviations of dense gas from the ideal laws and using our own Sun to supply a determination of the unknown constant involved. We can calculate the maximum temperature reached by different masses; for example, a star must have at least + the mass of the Sun in order to reach the lowest spectral type, M; and in order to reach the hottest type, B, it must be at least 24 times as massive as the Sun. Happily for the theory no star has yet been found with a mass less than 4 of the Sun’s; and it is a well-known fact, discovered from the study _ of spectroscopic binaries, that the masses of the B stars are large com- _ pared with those of other types. Again, it is possible to calculate the _ difference of brightness of the giant and dwarf stars of type M, i.e. at the beginning and end of their career ; the result agrees closely with the observed difference. In the case of a class of variable stars in which the light changes seem to depend on a mechanical pulsation of the star, the knowledge we have obtained of the internal conditions enables us to predict the period of pulsation within narrow limits. For example, for 8 Cephei, the best-known star of this kind, the theoretical period is between 4 and 10 days, and the actual period is 53 days. Correspond- ing agreement is found in all the other cases tested. Our observational knowledge of the things here discussed is chiefly of a rather vague kind, and we can scarcely claim more than a general agreement of theory and observation. What we have been able to do in the way of tests is to offer the theory a considerable number of opportunities to ‘make a fool of itself,’ and so far it has not fallen into our traps. When the theory tells us that a star having the mass of the Sun will at one stage in its career reach a maximum effective temperature of 9,000° (the Sun’s effective temperature being 6,000°) we cannot do much in the way of checking it; but an erroneous theory might well have said that the maximum temperature was 20,000° (hotter than any known star), in which case we should have detected its error. Tf we cannot feel confident that the answers of the theory are true, it must be admitted that it has shown some discretion in lying without being found out. _ It would not be surprising if individual stars occasionally depart considerably from the calculated results, because at present no serious attempt has been made to take into account rotation, which may modify the conditions when sufficiently rapid. That appears to be the next step needed for a more exact study of the question. Probably the greatest need of stellar astronomy at the present day, in order to make sure that our theoretical deductions are starting on the right lines, is some means of measuring the apparent angular diameters ofstars. At present we can calculate them approximately from theory, but there is no observational check. We believe we know with fair accuracy the apparent surface brightness corresponding to each spectral type; then all that is necessary is to divide the total apparent brightness by this surface brightness, and the result is the angular area subtended by the star. The unknown distance is not involved, kecause surface brightness is independent of distance. Thus the estimation of the angular diameter of any star seems to be a very simple matter. For instance, the star with the greatest apparent diameter is almost certainly : | : | 42 SECTIONAL ADDRESSES. Betelgeuse, diameter 051”. Next to it comes Antares, 043”. Other examples are Aldebaran “022”, Arcturus “020”, Pollux 013”. Sirius comes rather low down with diameter 007”. The following table may be of interest as showing the angular diameters expected for stars of various types and visual magnitudes :— Probable Angular Diameters of Stars. Vis. Mag. | A | F | G | K | M eee | eS m. | iad | 7 | ” wt | mr 0-0 - | -0034 | -0054 -0098 0219 -0859 2-0 -0014 -0022 | -0039 -0087 | -0342 | +0016 0035 «| +0136 4-0 | “0005 0009 However confidently we may believe in these values, it would be an immense advantage to have this first step in our deductions placed beyond doubt. If the direct measurement of these diameters could be made with any accuracy it would make a wonderfully rapid advance in our knowledge. The prospects of accomplishing some part of this task are now quite hopeful. We have learnt with great interest this year that work is being carried out by interferometer methods with the 100-inch reflector at Mount Wilson, and the results are most promising, At present the method has only been applied to measuring the separation of close double stars, but there seems to be no doubt that an angular diameter of “05” is well within reach. Although the great mirror is used for convenience, the interferometer method does not in principle require great apertures, but rather two small apertures widely separated as in a range-finder. Prof. Hale has stated, moreover, that success- ful results were obtained on nights of poor seeing. Perhaps it would be unsafe to assume that ‘ poor seeing’ at Mount Wilson means quite the same thing as it does for us, and I anticipate that atmospheric disturbance will ultimately set the limit to what can be accomplished, But even if we have to send special expeditions to the top of one of the highest mountains in the world the attack on this far-reaching problem must not be allowed to languish. I spoke earlier of the radiation-pressure exerted by the outflowing heat, which has an important effect on the equilibrium of a star. It is quite easy to calculate what proportion of the weight of the material is supported in this way; it depends neither on the density nor opacity, but solely on the star’s total mass and on the molecular weight. No astronomical data are needed ; the calculation involves only fundamental physical constants found by laboratory researches. Here are the figures, first for average molecular weight 3:0 :— For mass } x Sun, fraction of weight supported by radiation- pressure = "044. For mass 5 x Sun, fraction of weight supported by radiation- pressure =°457. For molecular weight 5:0 the corresponding fractions are “182 and "645. | a A.—MATHEMATICS AND PHYSICS. 43 The molecular weight can scarcely go beyond this range,*» and for the conclusions [ am about to draw it does not much mattér which limit we take. Probably 90 per cent. of the giant stars have masses be- tween 4 and 5 times the Sun’s, and we see that this is just the range in which radiation-pressure rises from unimportance’ to importance. «It seems clear that a globe of gas of larger mass, in which radiation-pres- sure and gravitation are nearly balancing, would be likely to be unstable. The condition may not be strictly unstable in itself; but’a small rotation or perturbation would make it so. It may therefore be conjectured that, if nebulous material began to concentrate into a mass much greater than 5 times the Sun’s, it would probably break up, and continue to redivide until more stable masses resulted. Above the upper limit the chances of survival are small; when the lower limit is approached the danger has practically disappeared, and there is little likelihood of any further breaking-up. Thus the final masses are left distributed almost entirely between the limits given. To put the matter slightly differently, we are able to predict from general principles that the material of the stellar universe will aggregate primarily into. masses chiefly lying between 10°° and 10% grams; and this is just the magnitude of the masses of the stars according to astronomical observation.*® This study of the radiation and internal conditions of a star brings forward very pressingly a problem often debated in this Section: What is the source of the heat which the Sun and stars are continually squandering? The answer given is almost unanimous—that it is obtained from the gravitational energy converted as the star steadily contracts. But almost as unanimously this answer is ignored in its practical consequences. Lord Kelvin showed that this hypothesis, due to Helmholtz, necessarily dates the birth of the Sun about 20,000,000 years ago; and he made strenuous efforts to induce geologists and biologists to accommodate their demands to this time-scale. I do not think they proved altogether tractable. But it is among his own col- leagues, physicists and astronomers, that the most outrageous violations of this limit have prevailed. I need only refer to Sir George Darwin’s theory of the earth-moon system, to the present Lord Rayleigh’s deter- mination of the age of terrestrial rocks from occluded helium, and to all modern discussions of the statistical equilibrium of the stellar system. No one seems to have any hesitation, if it suits him, in carrying back the history of the earth long before the supposed date of formation of the solar system ; and in some cases at least this appears to be justified > As an illustration of these limits, iron has 26 outer electrons ; if 10 break away the average molecular weight is 5; if 18 break away the molecular weight is 3. Eggert (Phys. Zeits. 1919, p. 570) has suggested by thermodynamical] reasoning that in most cases the two outer rings (16 electrons) would break away in the stars. The comparison of theory and observation for the dwarf stars also points to a molecular weight a little greater than 3. 6 By admitting plausible assumptions closer limits could be drawn. Taking the molecular weight as 3.5, and assuming that the most critical, condition is when 4 of gravitation is counterbalanced (by analogy with the case of rotating spheroids, in which centrifugal force opposes gravitation and creates instability), we find that the critical mass is just twice that of the Sun, and stellar masses may be expected to cluster closely round this value, 44 SECTIONAL ADDRESSES. by experimental evidence which it is difficult to dispute. Lord Kelvin’s date of the creation of the Sun is treated with no more respect than Archbishop Ussher’s. The serious consequences of this contraction hypothesis are particu- larly prominent in the case of giant stars, for the giants are prodigal with their heat and radiate at least a hundred times as fast as the Sun. The supply of energy which suffices to maintain the Sun for 10,000,000 years would be squandered by a giant star in less than 100,000 years. The whole evolution in the giant stage would have to be very rapid. In 18,000 years at the most a typical star must pass from the initial M stage totype G. In 80,000 years it has reached type A, near the top of the scale, and is about to start on the downward path. Even these figures are probably very much over-estimated.’ Most of the naked-eye stars are still in the giant stage. Dare we believe that they were all formed within the last 80,000 years? The telescope reveals to us objects not only remote in distance but remote in time. We can turn it on a globular cluster and behold what was passing 20,000, 50,000, even 200,000 years ago—unfortunately not all in the same cluster, but different clusters representing different epochs of the past. As Shapley has pointed out, the verdict appears to be ‘nochange.’ This is perhaps not conclusive, because it does not follow that individual stars have suffered no change in the interval; but it is difficult to resist the impression that the evolution of the stellar universe proceeds at a slow, majestic pace, with respect to which these periods of time are insignificant. There is another line of astronomical evidence which appears to show more definitely that the evolution of the stars proceeds far more slowly than the contraction hypothesis allows ; and perhaps it may ulti- mately enable us to measure the true rate of progress. There are certain stars, known as Cepheid variables, which undergo a regular fluctuation of light of a characteristic kind, generally with a period of a few days. This light change is not due to eclipse. Moreover, the colour quality of the light changes between maximum and minimum, evidently pointing to a periodic change in the physical condition of the star. Although these objects were formerly thought to be double stars, it now seems clear that this was a misinterpretation of the spectroscopic evidence. There is in fact no room for the hypothetical companion star; the orbit is so small that we should have to place it inside the principal star. Everything points to the period of the light pulsation being something intrinsic in the star; and the hypothesis advocated by Shapley, that it represents a mechanical pulsation of the star, seems to be the most plausible. I have already mentioned that the observed period does in fact agree with the calculated period of mechanical pulsation, so that the pulsation explanation survives one fairly stringent test. But whatever the cause of the variability, whether pulsation or rotation, provided only that it is intrinsic in the 7 I have taken the ratio of specific heats at the extreme possible value, $; that is to say, no allowance has been made for the energy needed for ionisa- tion and internal vibrations of the atoms, which makes a further call on the scanty supply available. EE — a A.—MATHEMATICS AND PHYSICS. 45 star, and not forced from outside, the density must be the leading factor in determining the period. If the star is contracting so that its density changes appreciably, the period cannot remain constant. Now, on the contraction hypothesis the change of density must amount to at least 1 per cent. in 40 years. (I give the figures for § Cephei, the best- known variable of this class.) The corresponding change of period should be very easily detectable. For 6 Cephei the period ought to decrease 40 seconds annually. Now & Cephei has been under careful observation since 1785, and it is known that the change of period, if any, must be very small. S. Chandler found a decrease of period of 4, second per annum, and in a recent investigation E. Hertzsprung has found a decrease of #4, second perannum. The evidence that there is any decrease at all rests almost entirely on the earliest observations made before 1800, so that it is not very certain; but in any case the evolution is proceeding at not more than 33, of the rate required by the contraction hypothesis. There must at this stage of the evolution of the star be some other source of energy which prolongs the life of the star 400-fold. The time-scale so enlarged would suffice for practically all reasonable demands. I hope the dilemma is plain. Hither we must admit that whilst the density changes 1 per cent. a certain period intrinsic in the star can change no more than z3, of 1 per cent., or we must give up the con- traction hypothesis. If the contraction theory were proposed to-day as a novel hypothesis IT do not think it would stand the smallest chance of acceptance. From all sides—biology, geology, physics, astronomy—it would be objected that the suggested source of energy was hopelessly inadequate to provide the heat spent during the necessary time of evolution; and, so far as it is possible to interpret observational evidence confidently, the theory would be held to be definitely negatived. Only the inertia of tradition keeps the contraction hypothesis alive—or rather, not alive, but an unburied corpse. But if we decide to inter the corpse, let us frankly recognise the position in which we are left. A star is drawing on some vast reservoir of energy by means unknown to us. This reservoir can scarcely be other than the sub-atomic energy which, it is known, exists abundantly in all matter; we sometimes dream that man will one day learn how to release it and use it for his service. The store is well-nigh inexhaustible, if only it could be tapped. There is sufficient in the Sun to maintain its output of heat for 15 billion years. Certain physical investigations in the past year, which I hope we may hear about at this meeting, make it probable to my mind that some portion of this sub-atomic energy is actually being set free in the stars. F. W. Aston’s experiments seem to leave no room for doubt that all the elements are constituted out of hydrogen atoms bound together with negative electrons. The nucleus of the helium atom, for example, consists of 4 hydrogen atoms bound with 2 electrons. But Aston has further shown conclusively that the mass of the helium atom is less than the sum of the masses of the 4 hydrogen atoms which enter into it; and in this at any rate the chemists agree with him. There is a loss of mass in the synthesis amounting to about 1 part in 120, the. 46 . SECTIONAL ADDRESSES. atomic weight of hydrogen being 1008 and that of helium just 4. I will riot dwell on his beautiful proof of this, as.you will no doubt be able to hear it from himself. Now mass cannot be annihilated, and the deficit can only represent the mass of the electrical energy set free in the transmutation. We can therefore at once calculate the quantity of energy liberated when helium is made out of hydrogen. If 5 per cent. of a star’s mass consists initially of hydrogen atoms, which are gradually being combined to form more complex elements, the total heat liberated will more than suffice for our demands, and we need look no further for the source of a star’s energy. But is it possible to admit that such a transmutation is occurring? It is difficult to assert, but perhaps more difficult to deny, that this is going on. Sir Ernest Rutherford has recently been breaking down the atoms of oxygen and nitrogen, driving out an isotope of helium from them ; and what is possible in the Cavendish laboratory may not be too difficult in the Sun. I think that the suspicion has been generally entertained that the stars are the crucibles in which the lighter atoms which abound in the nebule are compounded into more complex elements. In the stars matter has its preliminary brewing to prepare the greater variety of elements which are needed for a world of life. The radio-active elements must have been formed at no very distant date; and their synthesis, unlike the generation of helium from hydrogen, is endothermic. If combinations requiring the addition of energy can occur in the stars, combinations which liberate energy ought not to be impossible. We need not bind ourselves to the formation of helium from hydrogen as the sole reaction which supplies the energy, although it would seem that the further stages in building up the elements involve much less liberation, and sometimes even absorption, of energy. It is @ question of accurate measurement of the deviations of atomic weights from integers, and up to the present hydrogen is the only element for which Mr. Aston has been able to detect the deviation. No doubt we shall learn more about the possibilities in due time. The position may be summarised in these terms: the atoms of all elements are built of hydrogen atoms bound together, and presumably have at one time been formed from hydrogen; the interior of a star seems as likely a place as any for the evolution to have occurred ; whenever it did occur a great amount of energy must have been set free; in a star a vast quantity of energy is being set free which is hitherto unaccounted for. You may draw ‘a conclusion if you like. lf, indeed, the sub-atomic energy in the stars is being freely used to maintain their great furnaces, it seems to bring a little nearer to fulfilment our dream of controlling this latent power for the well-being of the human race—or for its suicide. So far as the immediate needs of astronomy are concerned, it is not of any great consequence whether in this suggestion-we have actually laid a finger on the true source of the heat. It is sufficient if the discussion opens’ our eyes to the wider possibilities: We can get rid of the obsession that there is no other conceivable supply besides con- traction, buf we need not again cramp ourselves by adopting prematurely iit ni A.—-MATHEMATICS AND PHYSICS. 47 what is perhaps a still wilder guess. Rather we should admit that the source is not certainly known, and seek for any possible astronomical evidence which may help to define its necessary character. One piece of evidence of this kind may be worth mentioning. It seems clear that it must be the high temperature inside the stars which determines the liberation of energy, as H. N. Russell has pointed out.® If so the supply may come mainly from the hottest region at the centre. I have already stated that the general uniformity of the opacity of the stars is much more easily intelligible if it depends on scattering rather than on true absorption ; but it did not seem possible to reconcile the deduced stellar opacity with the theoretical scattering coefficient. | Within reasonable limits it makes no great difference in our calculations at what parts of the star the heat energy is supplied, and it was assumed that it comes more or less evenly from all parts, as would be the case on _ the contraction theory. The possibility was scarcely contemplated that the energy is supplied entirely in a restricted region round the centre. Now, the more concentrated the supply, the lower is the opacity requisite to account for the observed radiation. I have not made any detailed calculations, but it seems possible that for a sufficiently concentrated source the deduced and the theoretical coefficients could be made to agree, and there does not seem to be any other way of accomplishing this. Conversely, we might perhaps argue that the present discrepancy of the coefficients shows that the energy supply is not spread out in the way required by the contraction hypothesis, but belongs to some new source only available at the hottest, central part of the star. I should not be surprised if it is whispered that this address has at times verged on being a little bit speculative; perhaps some outspoken friend may bluntly say that it has been highly speculative from begimning to end. I wonder what is the touchstone by which we may test the legitimate development of scientific theory and reject the idly speculative. We all know of theories which the scientific mind in- stinctively rejects as fruitless guesses; but it is difficult to specify their exact defect or to supply a rule which will show us when we ourselves do err. It is often supposed that to speculate and to make hypotheses are the same thing; but more often they are opposed. It is when we let our thoughts stray outside venerable, but sometimes insecure, hypotheses that we are said to speculate. Hypothesis limits speculation. Moreover, distrust of speculation often serves as a cover for loose thinking ; wild ideas take anchorage in our minds and influence our out- look; whilst it is considered too speculative to subject them to the scientific scrutiny which would exorcise them. ¢ If we are not content with the dull accumulation of experimental facts, if we make any deductions or generalisations, if we seek for any theory to guide us, some degree of speculation cannot be avoided. Some will prefer to take the interpretation which seems to be most imme- diately indicated and at once adopt that as an hypothesis; others will rather seek to explore and classify the widest possibilities which are not definitely inconsistent with the facts. Hither choice has its dangers ; 8 Pub. Act. Soc. Pacific. August 1919. 48 SECTIONAL ADDRESSES. the first may be too narrow a view and lead progress into a cul-de-sac ; the second may be so broad that it is useless as a guide, and diverges indefinitely from experimental knowledge. When this last case happens, it must be concluded that the knowledge is not yet ripe for theoretical treatment and speculation is premature. The time when speculative theory and observational research may profitably go hand in hand is when the possibilities, or at any rate the probabilities, can be narrowed down by experiment, and the theory can indicate the tests by which the remaining wrong paths may be blocked up one by one. f The mathematical physicist is in a position of peculiar difficulty. He may work out the behaviour of an ideal model of material with specifically defined properties, obeying mathematically exact laws, and so far his work is unimpeachable. It is no more speculative than the binomial theorem. But when he claims a serious interest for his toy, when he suggests that his model is like something going on in Nature, he inevitably begins to speculate. Is the actual body really like the ideal model? May not other unknown conditions intervene? He cannot be sure, but he cannot suppress the comparison; for it is by looking continually to Nature that he is guided in his choice of a sub- ject. A common fault, to which he must often plead guilty, is to use for the comparison data over which the more experienced observer shakes his head; they are too insecure to build extensively upon. Yet even in this, theory may help observation by showing the kind of data which it is especially important to improve. I think that the more idle kinds of speculation will be avoided if the investigation is conducted from the right point of view, When the properties of an ideal model have been worked out by rigorous mathe- matics, all the underlying assumptions being clearly understood, then it becomes possible to say that such and such properties and laws lead precisely to such and such effects. If any other disregarded factors are present, they should now betray themselves when a comparison is made with Nature. There is no need for disappointment at the failure of the model to give perfect agreement with observation; it has served its purpose, for it has distinguished what are the features of the actual phenomena which require new conditions for their explanation. A general preliminary agreement with observation is necessary, otherwise the model is hopeless ; not that it is necessarily wrong so far as it goes, but it has evidently put the less essential properties foremost. We have been pulling at the wrong end of the tangle, which has te be un- ravelled by a different approach. But after a general agreement with observation is established, and the tangle begins to loosen, we should always make ready for the next knot. I suppose that the applied mathematician whose theory has just passed one still more stringent test by observation ought not to feel satisfaction, but rather disappointment —‘ Foiled again! This time I had hoped to find a discordance which would throw light on the points where my model could be improved.’ Perhaps that is a counsel of perfection; I own that I have never felt very keenly a disappointment of this kind. Our model of Nature should not be like a building—a handsome A.—MATHEMATICS AND PHYSICS. 49 structure for the populace to admire, until in the course of time someone takes away a corner-stone and the edifice comes toppling down. It should be like an engine with movable parts. We need not fix the position of any one lever; that is to be adjusted from time to time as the latest observations indicate. The aim of the theorist is to know the train of wheels which the lever sets in motion—that binding of the parts which is the soul of the engine. In ancient days two aviators procured to themselves wings. Deedalus flew safely through the middle air across the sea, and was duly honoured on his landing. Young Icarus soared upwards towards the Sun till the wax melted which bound his wings, and his flight ended in fiasco. In weighing their achievements perhaps there is something to be said for Icarus. The classic authorities tell us that he was only ‘ doing a stunt,’ but I prefer to think of him as the man who certainly brought to light a constructional defect in the flying-machines of his day. So too in science... Cautious Dedalus will apply his theories where he feels most confident they will safely go; but by his excess of caution their hidden weaknesses cannot be brought to light. Icarus will strain his theories to the breaking-point till the weak joints gape. For a spectacular stunt? Perhaps partly; he is often very human. But if he is not yet destined to reach the Sun and solve for all time the riddle of its constitution, yet he may hope to learn from his journey some hints to build a better machine. 1920 z SECTION B: CARDIFF, 1920. ADDRESS TO THE Y CHEMICAL SECTION BY C. T. HEYCOCK, M.A., F.B.S., PRESIDENT OF THE SECTION. During its past eighty-nine years of useful life the British Association has, in the course of its evolution, established certain traditions ; among these is the expectation that the sectional President shall deliver an address containing a summary of that branch of natural knowledge with which he has become especially acquainted. The rapid accumulation of experimental observations during the last century, and the consequent necessity for classifying the observed facts with the aid of hypotheses and theories of ever-increasing com- plexity, make such summaries of knowledge essential, not only to the student of science, but also to the person of non-specialised education who desires to realise something of the tendencies and of the results of modern science. At the present moment, when the whole world is in pause after having overcome the greatest peril which has ever threatened civilisa- tion; when all productive effort, social, artistic, and scientific, is under- going reorganisation preparatory to an advance which will eclipse in importance the progress made during the nineteenth century, such attempts to visualise the present condition of knowledge as are made in our Presidential Addresses are of particular value. It is, therefore, hardly necessary for me to apologise for an endeavour to place before you a statement upon the particular branch of science to which I have myself paid special attention; whatever faults may attend the mode of presentation, such a survey of a specific field of knowledge cannot but be of value to some amongst us. I propose to deal to-day with the manner in which our present rather detailed knowledge of metallic alloys has been acquired, starting from the sparse information which was available thirty or forty years ago; B.—CHEMISTRY. 51 to show the pitfalls which have been avoided in the theoretical inter- pretation of the observed facts, and to sketch very briefly the present position of our knowledge. The production of metals and their alloys undoubtedly constitutes the oldest of those chemical arts which ultimately expanded into the modern science of chemistry, with all its overwhelming mass of experi- mental detail and its intricate interweaving of theoretical interpretation of the observed facts. Tubal-Cain lived during the lifetime of our common ancestor, and was ‘an instructor of every artificer in brass and iron’; and although it may be doubted whether the philologists have yet satisfactorily determined whether Tubal-Cain was really acquainted with the manufacture of such a complex metallic alloy as brass, it is certain that chemical science had its beginnings in the reduction of metals from their ores and in the preparation of useful alloys from those metals. In fact, metallic alloys, or mixtures of metals, have been used by mankind for the manufacture of implements of war and of agriculture, of coiage, statuary, cooking vessels, and the like from the very earliest times. In the course of past ages an immense amount of practical informa- tion has been accumulated concerning methods of reducing metals, or mixtures of metals, from their ores, and by subsequent treatment, usually by heating and cooling, of adapting the resulting metallic product to the purpose for which it was required. Until quite recent times, however, the whole of this knowledge was entirely empirical in character, because it had no foundation in general theoretical prin- ciples ; it was collected in haphazard fashion in accordance with that method of trial and error which led our forerunners surely, but with excessive expenditure of time and effort, to valuable results. To-day I purpose dealing chiefly with the non-ferrous alloys, not because any essential difference in type exists between the ferrous and non-ferrous alloys, but merely because the whole field presented by the chemistry of the metals and their alloys is too vast to be covered in any reasonable length of time. _ The earliest recorded scientific investigations on alloys were made in 1722 by Reaumur, who employed the microscope to examine the fractured surfaces of white and grey cast iron and steel. In 1808 Widmanstatten cut sections from meteorites, which he polished and etched. The founder, however, of modern metallography is undoubtedly H. C. Sorby, of Sheffield. Sorby’s early petrographic work on the examination of thin sections of rock under the microscope led him to a study of meteorites and of iron and steel, and in a paper read before the British Association in 1864 he describes briefly (I quote his own words) how sections ‘of iron and steel may be prepared for the microscope so as to exhibit their structure to a perfection that leaves little to be desired. They show various mixtures of iron, and two or three well-defined compounds of iron and carbon, graphite, and slag; these constituents being present in different proportions and arranged in various manners, give rise to a large number of varieties of iron and steel, differing by well-marked and very striking peculiarities E2 ct to SECTIONAL ADDRESSES. of structure.’ The methods described by Sorby for polishing and etching alloys and his method of vertical illumination (afterwards improved by Beck) are employed to-day by all who work at this branch of metallography. The lantern-slides, now shown, were reproduced from his original photographs; they form a lasting memorial to his skill as an investi- gator.and his ability as a manipulator. In 1887 Dr. Sorby published a paper on the microscopical structure of iron and steel in the Journal of the Iron and Steel Institute. This masterpiece of clear writing and expression, even with our present knowledge, needs but little emendation. In this paper he describes Free Iron (ferrite) carbon as graphite, the pearly constituent as a very fine laminar structure (pearlitic structure), combined iron as the chief constituent of white cast iron (cementite), slag inclusions, effect of tempering steel, effect of working iron and steel, cementation of wrought iron, and the decarbonisation of cast iron by haematite. A truly remarkable achievement for one man. From 1854-68 Mattheisen published in the Reports of the British Association and in the Proceedings and Transactions of the Royal Society, a large number of papers on the electrical conductivity, tenacity, and specific gravity of pure metals and alloys. He concluded that alloys are either mixtures of definite chemical compounds with an excess of one or other metal, or solutions of the definite alloy in the excess of one of the metals employed, forming, in their solid condition, what he called a solidified solution. This idea of a solidified solution has developed into a most fruitful theory upon which much of our modern notions of alloys depends. Although, at the time, the experi- ments on the electrical conductivity did not lead to very definite con- clusions, the method has since been used with great success in testing for the presence of minute quantities of impurities in the copper used for conductors. In the Philosophical Magazine for 1875, F. Guthrie, in a remarkable paper, quite unconnected with alloys, gave an account of his experiments on salt solutions and attached water. He was led to undertake this work by a consideration of a paper by Dr. J. Rea, the Arctic explorer, on the comparative saltness of freshly formed and of older ice floes. Guthrie showed that the freezing-point of solutions was continuously diminished as the percentage of common salt increased, and that this lowering increased up to 23.6 per cent. of salt, when the solution’ solidified as a whole at about 229 C. He further showed, and this is of great importance, that the substance which first separated from solutions more dilute than 23.6 was pure ice. To the substance which froze as a whole, giving crystals of the same composition as the mother liquor, he gave the name cryohydrate. At the time he thought that the cryohydrate of salt containing 23.6 per cent. NaCl and 76.4 per cent. of water was a chemical compound 2NaCl.21H,0. In suc- ceeding years he showed that a large number of other salts gave solu- tions which behaved in a similar manner to common salt. He abandoned the idea that the cryohydrates were chemical compounds. How clear his views were will be seen by quotations from his B.—CHEMISTRY. 53) paper in the Phil. Mag. (5) 1. and II., 1876, in which he states: (i.) When a@ solution weaker than the cryohydrate loses heat, ice is formed. (ii.) Ice continues to form and the temperature to fall until’ the cryohydrate is reached. (iii.) At’the point of saturation ice and: salt separate simultaneously and the solid and liquid portions are identical in composition. ins These results can be expressed in the form of a simple diagram as’ shown in the slide. In a subsequent paper, Phil. 'Mag. (5) 17, he extends his experi- , ments to solvents other than water,, and states that the substances which separate at the lowest temperature are neither atomic nor mole- cular; this lowest melting-point mixture of two bodies he names the: eutectic mixture. In the same paper he details the methods of obtain- ing various eutectic alloys of bismuth, lead, tin, and cadmium. We have, in these papers of Guthrie’s, the first important clue to what occurs on cooling a fused mixture of metals. The researches of - Sorby and Guthrie, undertaken as they were for the sake of investigat- ing natural phenomena, are a remarkable example of how purely scientific experiment can lead to most important practical results. It is not too much to claim for these investigators the honour of being the originators of all our modern ideas of metallurgy. Although much valuable information had been accumulated, no rapid advance could be made until some general theory of solution had been developed. In 1878 Raoult first began his work on the depression of the freezing- point of solvents due to the addition of dissolved substances, and he continued, at frequent intervals, to publish the results of his experi- ments up to the time of his death in 1901. He established for organic’ solvents certain general laws: (i.) that for moderate concentrations the: fall of the freezing-point is proportional to the weight of the dissolved substance present in a constant weight of solvent; (ii.) that when the falls produced in the same solvent by different dissolved substances are compared, it is found that a molecular weight of a dissolved substance produces the same fall of the freezing-point, whatever the substance is. When, however, he applied the general laws which he had established for organic solvents to aqueous solutions of inorganic acids, bases, and salts, the results obtained were hopelessly discrepant. In a paper in the Zeit. Physikal. Chem. for 1888 on ‘Osmotic Pressure in the analogy between solutions and gases,’ Van’t Hoff showed that the experiments of Pfeffer on osmotic pressure could be explained on the theory that dissolved substances were, at any rate for dilute solu- tions, in a condition similar to that of a gas; that they obeyed the laws of Boyle, Charles, and Avogadro, and that on this assumption the: depression of the freezing-point of a solvent could be calculated by means of a simple formula. He also showed that the exceptions which occurred to Raoult’s laws, when applied to aqueous solutions of electrolytes, could’ be explained by the assumption, first made by Arrhénius, that’ these latter in solution are partly dissociated into their ions. The result of all this work was to establish a general theory applicable to all solutions which has been widespread in its appli- . eations. It is true that Van’t Hoff’s theory has been violently attacked ; . 64 SECTIONAL ADDRESSES. but it enables us to calculate the depression of the freezing-points of a large number of solvents. To do this it is necessary to know the latent heat of fusion of the pure solvent and the absolute temperature of the freezing-point of the solution. That the numbers calculated are in very close accord with the experimental values constitutes a strong argu- ment in favour of the theory. From this time the study of alloys began to make rapid progress. Laurie (Chem. Soc. Jour. 1888), by measuring the potential difference of voltaic cells composed of plates of alloy and the more negative element immersed in a solution of a salt of one of the component metals, obtained evidence of the existence of compounds such as CuZn,.Cu,Sn. In 1889 F. H. Neville and I, whilst repeating Raoult’s experiments on the lowering of the freezing- point of organic solvents, thought that it was possible that the well- ‘known fact that alloys often freeze at a lower temperature than either of their constituents might be explained in a similar way. In a pre- Jiminary note communicated to the Chemical Society on March 21, 1889, on the same evening that Professor Ramsay read his paper on the molecular weights of metals as determined by the depression of the vapour pressure, we showed that the fall produced in the freezing- point of tin by dissolving metals in it was for dilute solutions directly proportional to the concentration. We also showed that the fall pro- duced in the freezing-point of tin by the solution of one atomic weight of metal in 100 atomic weights of tin was a constant. G. Tannman about the same time (Zeit. Physikal. Chemie, III., 44, 1889) arrived at a similar conclusion, using mercury as a solvent. These experiments helped to establish the similarity between the behaviour of metallic solutions or alloys and that. of aqueous and other solutions of organic compounds in organic solvents. That our experi- ments were correct seemed probable from the agreement between the observed depression of the freezing-point and the value calculated from Van’t Hoff’s formula for the case of those few metals whose latent heats of fusion had been determined with any approach to accuracy. Our experiments, subsequently extended to other solvents, led to the conclusion that in the case of most metals dissolved in tin the molecular weight is identical with the atomic weight; in other words, that the metals in solution are monatomic. This conclusion, however, involves certain assumptions. Prof. Ramsay’s experiments on the lowering of the vapour pressure of certain amalgams point to a similar conclusion. So far our work had been carried out with mercury thermometers, standardised against a platinum resistance pyrometer, but it was evident that, if it was to be continued, we must have some method of extend- ing our experiments to alloys which freéze at high temperatures. The thermo couple was not at this stage a reliable instrument; fortunately, however, Callendar and Griffiths had brought to great perfection the electrical resistance pyrometer (Phil. Trans. A, 1887 and 1891). Dr. BE. H. Griffiths kindly came to our aid, and with his help we installed a complete electrical resistance set. As at this time the freezing-points of pure substances above 300° were not known with any degree of accuracy, we began by making these measurements :— B.—CHEMISTRY. crt cr Table of Freezing-poimts. | { Burgess & ‘Camenty’s| Holborn | Callendar | Neville Berek — Tables | & Wien, & Griffiths, & Heycock,| 11,7) mn, | 1892 1892 | 1895 Be OP perature | Measure- és iodyesy tn ask joa | ments Tm , 3 5 —_ — 231-7 | -231°9 231°9 Zine . q - ~~ 433 — 4176 | 419°0 419°4 Lead . A - “ — _ — 327°6 327°4 Antimony. . . | 432 — | ~~ | 6295 | 630-7 & | | | | | 629-2 Magnesium. 3 . oo Se 1632°6 650 | Aluminium il 700 —_— : _ *654'5 658 Silver : 4 af 954 968 | 972 960°7 960°9 Gold . $ . | 1,045 1,072 1,037 1,061°7 1,062°4 Copper . . .| 1,054 1,082 ie, 1,080°3 | 1,083 | SulphurB.P. . . | 448 — | 44453 is 444-7 ' Contaminated with silicon. 2 Known to be impure. With the exception of silver and gold, these metals were the purest obtainable in commerce. Two facts are evident from the consideration of this table: (a) the remarkable accuracy of Callendar’s formula connecting the Tempera- ture Centigrade with the change of resistance of a pure platinum wire ; (b) the accuracy of Callendar and Griffiths’ determination of the boiling- point of sulphur. Although the platinum resistance pyrometer had at this time only been compared with the air thermometer up to 600° C., ib will be noted that the exterpolation from 600° to nearly 1,100 was justified. I cannot leave the subject of high-temperature measurements with- out referring to the specially valuable work of Burgess, and also to Eza Griffiths’ book on high-temperature measurements, which contains an excellent summary of the present state of our knowledge of this important subject. During the period that the above work on non-ferrous alloys was being done, great progress was being made in the study of iron and steel by Osmond and Le Chatelier. In 1890 the Institute of Mechanical Engineers, not apparently without considerable misgivings on the part of some of its members, formed an Alloys Research Committee. This Committee invited Professor (afterwards Sir William) Roberts-Austen to undertake research work for them. The results of his investigations are contained in a series of five valuable reports, extending from 1891 to 1899, published in the Journal of the Institute. The first report contained a deseription of an improved form of the Le Chatelier record- ing pyrometer, and the instrument has since proved a powerful weapon of research. In the second report, issued in 1893, the effects on the properties of copper of small quantities of arsenic, bismuth, and antimony were discussed. Whilst some engineers advocated, others as strongly controverted, the beneficial results of small quantities of 56 SECTIONAL ADDRESSES. arsenic on the copper used for the fireboxes of locomotives. The report showed that the presence of from °5-1 per cent. of arsenic was highly beneficial. The third report dealt with electric welding and the production of alloys of iron and aluminium. The fourth report is particularly valuable, as it contains a résumé of the Bakerian Lecture given by Roberts-Austen on the diffusion of metals in the solid state, in which he showed that gold, even at as low a temperature as 100°, could penetrate into lead, and that iron became carbonised at a low red heat by contact with a diamond in a vacuum. In 1899 the fifth report appeared, on the effects of the addition of carbon to iron. This report is of especial importance, because, besides a description of the thermal effects produced by carbon, which he carefully plotted and photographed, he described the microscopical appearance of the various constituents of iron. The materials of this report, together with the work of Osmond and others on steel and iron, provided much of the material on which Professor Bakhuis Roozeboom founded the iron carbon equilibrium diagram. Reference should also be made to the very valuable paper by Stansfield on the present position of the solution theory of carbonised iron (Journ. Iron and Steel Inst., 11, 1900, p. 317). It may be said of this fifth report, and the two papers just referred to, that they form the most important contribution to the study of iron and steel that has ever been published. Although the diagram for the: equilibrium of iron and carbon does not represent the whole of the facts, it affords the most important clue to these alloys, and undoubtedly. forms the basis of most of the modern practice of steel manufacture. (Slide showing iron carbon diagram.) Many workers, both at home and abroad, were now actively engaged in metallurgical work—Stead, Osmond, Le Chatelier, Arnold, Hadfield, Carpenter, Ewing, Rosenhain, and others too numerous to mention. In 1897 Neville and I determined the complete freezing-point curve of the copper-tin alloys, confirming and extending the work of Roberts- Austen, Stansfield, and Le Chatelier; but the real meaning of the curve remained as much of a mystery as ever. Early in 1900 Sir G. Stokes suggested to us that we should make a microscopic examination of a few bronzes as an aid to the interpretation of the singularities of the freezing-point curve. An account of this work, which occupied us for more than two years,-was published as the Bakerian Lecture of the Royal Society in February 1903. Whilst preparing a number of copper-tin alloys of known composition we were struck by the fact that the crystalline pattern which developed on the free surface of the slowly cooled alloys was entirely unlike the structure developed by polishing and etching sections cut from the interior; it therefore appeared probable that changes were going on within the alloys as they cooled. In the hope that, as Sorby had shown in the case of steel, we could stereotype or fix the change by sudden cooling, we melted small ingots of the copper-tin alloys and slowly cooled them to selected temperatures and then suddenly chilled them in water.’ The results of this treatment were communicated to the Royal Society and published in the Proceedings, February 1901. (Slides showing effects of chilling alloys.) B.—CHEMISTRY. 57 To apply this method to a selected alloy we first determined its cooling curve by means of an automatic recorder, the curve usually showing several halts or steps in it. The temperature of the highest of these steps corresponded with a point on the liquidus, i.e., when solid first separated out from the molten mass. To ascertain what occurred at the subsequent halts, ingots of the melted alloy were slowly cooled to within a few degrees above and below the halt and then chilled, with the result just seen on the screen. The method of chilling also enabled us to fix, with some degree of accuracy, the position of points on the solidus. If an alloy, chilled when it is partly solid and partly liquid, is polished and etched, it will be seen to consist of large primary combs embedded in a matrix consisting of mother liquor, in which are disseminated numerous small combs, which we called ‘ chilled primary.’ By repeating the process at successively lower and lower temperatures we obtained a point at which the chilled primary no longer formed, i.e., the upper limit of the solidus. Although we made but few determinations of the physical properties of the alloys, it is needless to say how much they vary with the temperature and with the rapidity with which they are heated or cooled. From a consideration of the singularities in the liquidus curve, coupled with the microscopic examination of slowly cooled and chilled alloys, we were able to divide the copper-tin alloys into certain groups having special qualities. It would take far too long to discuss these divisions. In interpreting our result we were greatly assisted not only by the application of the phase rule, but also by the application of Roozeboom’s theory of solid solution (unfortunately Professor Rooze- boom’s letters were destroyed by fire in June 1910) and by the advice he kindly gave us. At the time the paper was published we expressly stated that we did not regard all our results as final, as much more work was required to clear up points still obscure. Other workers— Shepherd and Blough, Giolitti and Tavanti—have somewhat modified the diagram. (Slides shown.) Neither Shepherd and Blough nor Hoyt have published the photo- micrographs upon which their results are based, so that it is impos- sible to criticise their conclusions. Giolitti and Tavanti have published some microphotographs, from which it seems that they had not allowed sufficient time for equilibrium to be established. In this connection I must call attention to the excellent work of Haughton on the con- stitution of the alloys of copper and tin (Journ. Institute of Metals, March 1915). He investigated the alloys rich in tin, and illustrated his conclusions by singularly beautiful microphotographs, and has done much to clear up doubtful points in this region of the diagram. I have dwelt at some length on this work, for copper-tin is probably the first of the binary alloys on which an attempt had been made to determine the changes which take place in passing from one pure constituent to the other. I would again call attention to the fact that without a working theory of solution the interpretation of the results would have been impossible. Since 1900, many complete equilibrium diagrams have been pub- 58 SECTIONAL ADDRESSES. lished ; amongst them may be mentioned the work of Rosenhain and Tucker on the lead-tin alloys (Phil. Trans., 1908), in which they describe hitherto unsuspected changes on the lead rich side which go on when these alloys are at quite low temperatures, also the constitution of the alloys of aluminium and zinc; the work of Rosenhain and Archbutt (Phil. Trans., 1911), and quite recently the excellent work of Vivian, on the alloys of tin and phosphorus, which has thrown an entirely new light on this difficult subject. So far I have called attention to some of the difficulties encountered in the examination of binary alloys. When we come to ternary alloys the difficulties of carrying out an investigation are enormously increased, whilst with quaternary alloys they seem almost insurmountable; in the case of steels containing always six, and usually more, constituents, we can only hope to get information by purely empirical methods. Large numbers of the elements and their compounds which originally were laboriously prepared and investigated in the. laboratory and remained dormant as chemical curiosities for many years have, in the fulness of time, taken their places as important and, indeed, essential articles of commerce. Passing over the difficulties encountered by Davy in the preparation of metallic sodium and by Faraday in the production of benzene (both of which materials are manufactured in enormous quantities at the present time), I may remark that even during my own lifetime I have seen a vast number of substances trans- ferred from the category of rare laboratory products to that which comprises materials of the utmost importance to the modern metal- lurgical industries. A few decades ago, aluminium, chromium, cerium, thorium, tungsten, manganese, magnesium, molybdenum, nickel, calcium and calcium carbide, carborundum, and acetylene were un- known outside the chemical laboratory of the purely scientific inyesti- gator; to-day these elements, their compounds and alloys, are amongst the most valuable of our industrial metallic products. They are essential in the manufacture of high-speed steels, of armour-plate, of filaments for the electric bulb lamp, of incandescent gas mantles, and of countless other products of modern scientific industry. All these metallic elements and compounds were discovered, and their industrial uses foreshadowed, during the course of the purely academic research work carried out in our Universities and Colleges ; all have become the materials upon which great and lucrative industries have been built up. Although the scientific worker has certainly not ex- hibited any cupidity in the past—although he has been content to rejoice in his own contributions to knowledge, and to see great. manufacturing enterprises founded upon his work—it is clear that the obligation devolves upon those who have reaped in the world’s markets the fruit of scientific discovery to provide from their harvest the financial aid without which scientific research cannot be continued. The truth of this statement is well understood by those of our great industrial leaders who are engaged in translating the results of scientific research into technical practice. As evidence of this I may quote the magnificent donation of 210,0001. by the British Oil Companies towards the endowment: of the School of Chemistry in the University of Cam- B.—CHEMISTRY. 59 bridge, the noble bequest of the late Dr. Messel, one of the most en- lightened of our technical chemists, for defraying the cost of scientific research, the gifts of the late Dr. Ludwig Mond towards the upkeep and expansion of the Royal Institution, one of the strongholds of British chemical research, and the financial support given by the Goldsmiths’ and others of the great City of London Livery Companies (initiated largely by the late Sir Frederick Abel, Sir Frederick Bramwell, and _ Mr. George Matthey), to the foundation of the Imperial College of Science and Technology. The men who initiated these gifts have been themselves intimately associated with developments both in ‘science and industry; they have understood that the field must be prepared before the crop can be reaped. Fortunately our great chemical indus- triés are, for the most part, controlled and administered by men fully conversant with the mode in which technical progress and prosperity follow upon scientific achievement ; and it is my pleasant duty to reeord that within the last few weeks the directors of one of our greatest chemical-manufacturing concerns have, with the consent of their shareholders, devoted £100,000 to research. Doubtless other chemical industries will in due course realise what they have to gain by an ade- quate appreciation of pure science. Tf the effort now being made to establish a comprehensive scheme for the resuscitation of chemical industry within our Empire is to succeed, financial support on a very liberal scale must be forthcoming, from the industry itself, for the advancement of purely scientific research. This question has been treated recently in so able a fashion by Lord Moulton that nothing now remains but to await the results of his appeal for funds in aid of the advancement of pure science. In order to prevent disappointment, and a possible reaction in the future, in those who endow pure research, it is necessary to give a word of warning. It must be remembered that the history of science abounds in illustrations of discoveries, regarded at the time as trivial, which have in after years become epoch-making. In illustration I would cite Faraday’s discovery of electro-magnetic induction. He found that when a bar magnet was thrust into the core of a bobbin of insulated copper wire, whose terminals were con- nected with a galvanometer, a momentary current was produced; whilst on withdrawing the magnet a momentary reverse current occurred; a purely scientific experiment destined in later years to develop into the dynamo and with it’ the whole electrical industry. Another illustration may be given: Guyton de Morveau, Northmore, Davy, Faraday and Cagniard Latour between 1800 and 1850 were engaged in liquefying many of the gases. Hydrogen, oxygen, nitrogen, marsh gas, carbon-monoxide, and nitric oxide, however, resisted all efforts, until the work of Joule and Andrews gave the clue to the causes of failure. Some thirty years later by careful application of the theoretical considerations all the gases were liquefied. The liquefaction of oxygen and nitrogen now forms the basis of a very large and important industry. _Such cases can be multiplied indefinitely in all branches of science. 60 SECTIONAL ADDRESSES. Perhaps the most pressing need of the present day lies in the cultivation of a better understanding between our great masters of productive industry, the shareholders to whom they are in the first. degree responsible, and our scientific workers; if, by reason of any turbidity of vision, our large manufacturing corporations fail to discern : that, in their own interest, the financial support of purely scientific research should be one of their first cares, technical advance will slacken and other nations, adopting a more far-sighted policy, will forge ahead in science and technology. It should, I venture to think, be the bounden duty of everyone who has at heart the aims and objects of the British Association to preach the doctrine that in closer sympathy between all classes of productive labour, manual and intellectual, lies our only hope for the future. I cannot do better than conclude by quoting the words of Pope, one of our most characteristically British poets : ‘ By mutual confidence and mutual aid Great deeds are done‘and great discoveries made.’ SECTION C: CARDIFF, 1920. ADDRESS TO THE GEOLOGICAL SECTION BY FRANOIS ARTHUR BATHER, M.A., D.Sc., F.RB.S., PRESIDENT OF THE SECTION. FOSSILS AND LIFE. Or the many distinguished men who have preceded me in this chair only eight can be described as essentially palaeontologists ; and among them few seized the occasion to expound the broader principles of their science. I propose, then, to consider the Relations of Palaeontology to the other Natural Sciences, especially the Biological, to discuss its particular contribution to biological thought, and to inquire whether its facts justify certain hypotheses frequently put forward in its name. Several of those hypotheses were presented to you in his usual masterly manner by Dr. Smith Woodward in 1909, and yet others are clearly elucidated in two Introductions to Palaeontology which we have been delighted to welcome as British products: the books by Dr. Morley Davies and Dr. H. L. Hawkins. If I subject those attractive specula- tions to cold analysis it is from no want of admiration or even sympathy, for in younger days I too have sported with Vitalism in the shade and been caught in the tangles of Transcendental hair. The Differentia of Palaeontology. Like Botany and Zoology, Palaeontology describes the external and internal form and structure of animals and plants; and on this description it bases, first, a systematic classification of its material ; secondly, those broader inductions of comparative anatomy which con- stitute morphology, or the science of form. Arising out of these studies are the questions of relation—real or apparent kinship, lines of descent, the how and the why of evolution—the answers to which reflect their light back on our morphological and classificatory systems. By a different approach we map the geographical distribution of genera and species, thus helping to elucidate changes of land and sea, and so barring out one hypothesis of racial descent or unlocking the door to another. Again, we study collective faunas and floras, unravelling the interplay of their component animals and plants, or inferring from each assem- blage the climatic and other physical agents that favoured, selected, and delimited it. 62 SECTIONAL ADDRESSES. All this, it may be said, is nothing more than the Botany and Zoology of the past. True, the general absence of any soft tissues, and the obscured or fragmentary condition of those harder parts which alone are preserved, make the studies of the palaeontologist more difficult, and drive him to special methods. But the result is less complete: in short, an inferior and unattractive branch of Biology. Let us relegate it to Section C! Certainly the relation of Palaeontology to Geology is obvious. It is a part of that general history of the Earth which is Geology. And it is an essential part even of physical geology, for without life not merely would our series of strata have lacked the coal measures, the mountain limestones, the chalks, and the siliceous earths, but the changes of land and sea would have been far other. To the scientific interpreter of Earth-history, the importance of fossils lies first in their value as date- markers ; secondly, in the light which they cast on barriers and currents, on seasonal and climatic variation. Conversely, the history of life has itself been influenced by geologic change. But all this is just as true of the present inhabitants of the globe as it is of their predecessors. It does not give the differentia of Palaeontology. That which above all distinguishes Palaeontology—the study of ancient creatures, from Neontology—the study of creatures now living, that which raises it above the mere description of extinct assemblages of life-forms, is the concept of Time. Not the quasi-absolute time of the clock, or rather, of the sun; not various unrelated durations; but an orderly and related succession, coextensive, in theory at least, with the whole history of life on this planet. The bearing of this obvious statement will appear from one or two simple illustrations. Effect of the Time-concept on Principles of Classification. Adopting the well-tried metaphor, let us imagine the tree of life buried, except for its topmost twigs, beneath a sand-dune. The neontolo- gist sees only the unburied twigs. He recognises certain rough group- ings, and eonstructs a classification accordingly. From various hints he may shrewdly infer that some twigs come from one branch, some from another; but the relations of the branches to the main stem are matters of speculation, and when branches have become so interlaced that their twigs have long been subjected to the same external influences, he will probably be led to incorrect conclusions. The palaeontologist then comes, shovels away the sand, and by degrees exposes the true relations of branches and twigs. His work is not yet accomplished, and probably he never will reveal the root and lower part of the tree; but already he has corrected many natural, if not inevitable, errors of the neontologist. I could easily occupy the rest of this hour by discussing the pro- found changes wrought by this conception on our classification. It is not that Orders and Classes hitherto unknown have been discovered, not that some erroneous allocations have been corrected, but the whole basis of our system is being shifted. So long as we were dealing with C.—GEOLOGY. 63 & horizontal section across the tree of life—that is to say, with an assem- blage of approximately contemporaneous forms—or even with a number of such horizontal sections, so long were we confined to simple descrip- tion. Any attempt to frame a causal connection was bound to be speculative. Certain relations of structure, as of cloven hooves with horns and with a ruminant stomach, were observed, but, as Cuvier him- self insisted, the laws based on such facts were purely empirical. Huxley, then, was justified in maintaining, as he did in 1863 and for long after, that a zoological classification could be based with profit on ‘ purely structural considerations’ alone. ‘ Every group in that [kind of] classification is such in virtue of certain structural characters, which are not only common to the members of that group, but distinguish it from all others; and the statement of these constitutes the definition of the group.’ In such a classification the groups or categories—from species and genera up to phyla—are the expressions of an arbitrary in- tellectual decision. From Linnaeus downwards botanists and zoologists have sought for a classification that should be not arbitrary but natural, though what they meant by ‘ natural ’ neither Linnaeus nor his succes- sors either could or would say. Not, that is, until the doctrine of descent was firmly established, and even now its application remains impracticable, except in those cases where sufficient proof of genetic connection has been furnished—as it has been mainly by palaeontology. In many cases we now perceive the causal connection ; and we recognise that our groupings, so far as they follow the blood-red clue, are not arbitrary but tables of natural affinity. Fresh difficulties, however, arise. Consider the branching of a tree. Tt is easy to distinguish the twigs and the branches each from each, but where are we to draw the line along each ascending stem? To con- vey the new conception of change in time we must introduce a new set of systematic categories, called grades or series, keeping our old cate- gories of families, orders, and the like for the vertical divisions between the branches. Thus, many crinoids with pinnulate arms arose from others in which the arms were non-pinnulate. We cannot place them in an Order by themselves, because the ancestors belonged to two or three Orders. We must keep them in the same Orders as their respec- tive ancestors, but distinguish a Grade Pinnata from a Grade Impin- nata. This sounds fairly simple, and for the larger groups so it is. But when we consider the genus, we are met with the difficulty that many of our existing genera represent grades of structure affecting a number of species, and several of those species can be traced back through previous grades. This has long been recognised, but I take a modern instance from H. F. Osborn’s ‘ Equidae’ (1918, Mem. Amer. Mus. N.H., ns. II. 51): ‘The line between such species as Miohippus (Mesohippus) meteulophus and M. brachystylus of the Leptauchenia zone and M. (Mesohippus) intermedius of the Protoceras zone is purely arbitrary. It is obvious that members of more than one phylum [i.e., lineage] are passing from one genus into the next, and Mesohippus meteulophus and M. brachystylus may with equal consistency be referred. to Miohippus.’ 64 SECTIONAL ADDRESSESs The problem is reduced to its simplest elements in the -following scheme :— | 4 Big Dr tC, AO Cink Italics. IE CHT: RP Lower-case Roman. ABCDEF Capitals Roman. a By Si €o Greek. Our genera are equivalent to the forms of letters: ~ Italics, Raintin; Greek, and so forth. The successive species are the letters themselves. Are we to make each species a genus? Or would it not be better to confess that here, as in the case of many larger groups, our basis of classification is wrong? For the palaeontologist, at any rate, the lineage a, A, a, a, is the all-important concept. Between these forms he finds every gradation ; but between a and 6 he perceives no connection. . Inthe old classification the vertical divisions either were arbitrary, or were gaps due to ignorance. We are gradually substituting a classification in which the vertical divisions are based» on knowledge, and the horizontal divisions, though in some degree: arbitrary, often coincide with relatively sudden or physiologically important changes) of form. This brings us to the last point of contrast. Quix Ji fanaa can no longer have the rigid character emphasised by Huxley. They are no longer purely descriptive. When it devolved on me to draw up a definition of the great group Echinoderma, a definition that should include all the fossils, I found that scarcely a character given in the textbooks could certainly be predicated of every member of the group. The answer to the question, ‘ What is an Echinoderm?’ (and you may substitute Mollusc, or Vertebrate, or what name you please) has to be of this nature: An HEchinoderm is an animal descended: from an ancestor possessed of such-and-such characters differentiating it from other animal forms, and it still retains the imprint ofthat ancestor, though modified and obscured in various ways according to the class, order, family, and genus to which it belongs. The etindibibean given by Professor Charles Schuchert in his classification of the Brachiopoda (1913, Eastman’s ‘ Zittel’) represent an interesting attempt to put these principles into practice. The Family Porambonitidae, for instance, is thus defined: ‘ Derived (out of Syntrophiidae), progressive, semi- rostrate Pentamerids, with the deltidia and chilidia vanishing more and more in. time. Spondylia and cruralia present, but the - former tends to thicken and unite with the ventral valve.’ The old form of diagnosis was per genus et differentiam. The new form is per proavum et modificationem. Even the conception of our fundamental unit, the species, is in- secure owing to the discovery of gradual changes. But this is a difficulty which the palaeontologist shares with the neontologist. Let us consider another way in which the time-concept has affected biology. Effect of the Time-concept on Ideas of Relationship. Etienne Geoffroy-Saint Hilaire was the first to. compare the embryonic stages of certain animals with the adult stages of animals considered 0.-—GEOLOGY. 65 inferior. Through the more precise observations of Yon Baer, Louis Agassiz, and others, the idea grew until it was crystallised by the poetic imagination of Haeckel in his fundamental law of the reproduction of life—namely, that every creature tends in the course of its individual development to pass through stages similar to those passed through in the history of its race. This principle is of value if applied with the necessary safeguards. If it was ever brought into disrepute, it was owing to the reckless enthusiasm of some embryologists, who unwarrantably extended the statement to all shapes and_ structures observed in the developing animal, such as those evoked by special conditions of larval existence, sometimes forgetting that every con- ceivable ancestor must at least have been capable of earning its own livelihood. Or, again, they compared the early stages of an individual with the adult structure of its contemporaries instead of with that of its predecessors in time. Often, too, the searcher into the embryology of creatures now living was forced to study some form that really was highly specialised, such as the unstalked Crinoid Antedon, and he made matters worse by comparing its larvae with forms far too remote in time. Allman, for instance, thought he saw in the developing Antedon a Cystid stage, and so the Cystids were regarded as the ancestors of the Crinoids; but we now find that stage more closely paralleled in some Crinoids of Carboniferous and Permian age, and we realise that the Cystid structure is quite different. Such errors were due to the ignoring of time relations or to lack of acquaintance with extinct forms, and were beautifully illustrated in those phylogenetic trees which, in the ’eighties, every dissector of a new or striking animal thought it his duty to plant at the end of his paper. The trees have withered, because they were not rooted in the past. A similar mistake was made by the palaeontologist who, happening on a new fossil, blazoned it forth as a jink between groups previously unconnected—and in too many cases unconnected still. This action, natural and even justifiable under the old purely descriptive system, became fallacious when descent was taken as the basis. In those days one heard much of generalised types, especially among the older fossils ; animals were supposed to combine the features of two or three classes. This mode of thought is not quite extinct, for in the last American edition of Zittel’s ‘ Palaeontology ’ Stephanocrinus is still spoken of as a Crinoid related to the Blastoids, if not also to the Cystids. Let it be clear that these so-called ‘ generalised’ or ‘ annectant’ types are not regarded by their expositors as ancestral. Of course, a genus existing at a certain period may give rise to two different genera of a succeeding period, as possibly the Devonian Coelocrinus evolved into Agaricocrinus, with concave base, and into Dorycrinus, with convex base, both Carboniferous genera. But, to exemplify the kind of state- ment here criticised, perhaps I may quote from another distinguished writer of the present century: ‘The new genus is a truly annectant form uniting the Melocrinidae and the Platycrinidae.” Now the genus in question appeared, so far as we know, rather late in the Lower Carboniferous, whereas both Platycrinidae and Melocrinidae were already 1920 2 66 SECTIONAL, ADDRESSES. established in Middle Silurian time, How is it possible that the far later form should unite these two ancient families? Even a mésalliance is inconceivable. In a word, to describe any such forms as ‘ annectant’ is not merely to misinterpret structure but to ignore time. As bold suggestions calling for subsequent proof these speculations had their value, and they may be forgiven in the neontologist, if not in the palaeontologist, if we regard them as erratic pioneer tracks blazed through a tangled forest, As our acquaintance with fossils enlarged, the general direction became clearer, and certain paths were seen to be impossible. In 1881, addressing this Association at York, Huxley could say: ‘ Fifty years hence, whoever undertakes to record the progress of palaeontology will note the present time as the epoch in which the law of succession of the forms of the higher animals was determined by the observation of palaeontological facts. He will point out that, just as Steno and as Cuvier were enabled from their knowledge of the empirical laws of co-existence of the parts of animals to conclude from a part to a whole, so the knowledge of the law of succession of forms empowered their successors to conclude, from one or two terms of such a succession, to the whole series, and thus to divine the existence of forms of life, of which, perhaps, no trace remains, at epochs of inconceivable remoteness in the past.’ Descent Not a Corollary of Succession. Note that Huxley spoke of succession, not of descent. Succession undoubtedly was recognised, but the relation between the terms of the succession was little understood, and there was no proof of descent. Leti us suppose all written records to be swept away, and an attempt made to reconstruct English history from coins. We could set out our monarchs in true order, and we might suspect that the throne was hereditary; but if on that assumption we were to make James I. the son of Hlizabeth—well, but that’s just what palaeontologists are con- stantly doing. The famous diagram of the Evolution of the Horse which Huxley used in his American lectures has had to be corrected in the light of the fuller evidence recently tabulated in a handsome volume by Professor H. F. Osborn and his coadjutors. Palaeotherium, which Huxley regarded as a direct ancestor of the horse, is now held to be only a collateral, as the last of the Tudors were collateral ancestors of the Stuarts. The later Anchitheriwum must be eliminated from the true line as a side-branch—a Young Pretender. Sometimes an apparent succession is due to immigration of a distant relative from some other region-—‘ The glorious House of Hanover and Protestant Succession.’ It was, you will remember, by such migrations that Cuvier explained the renewal of life when a previous fauna had become extinct. He admitted succession but not descent. If he rejected special creation, he did-not accept evolution. Descent, then, is not a corollary of succession. Or, to broaden the statement, history is not the same as evolution. History is a succession of events. Evolution means that each event has sprang’ from the pre- ceding one. .Not that the preceding event was the active cause of its successor, buf that it was a necessary condition of if. For the evolu- trat | 0.—GEOLOGY. 67 tionary biologist, a species contains in itself and its environment the possibility of producing its successor. ‘The words ‘its environment ’ are necessary, because a living organism cannot be conceived apart from its environment. They are important, because they exclude from the idea of organic evolution the hypothesis that all subsequent forms were implicit in the primordial protoplast alone, and were manifested either through a series of degradations, as when Thorium by successive disintegrations transmutes itself to Lead, or through fresh develop- ments due to the successive loss of inhibiting factors. I say ‘a species contains the possibility ’ rather than ‘ the potentiality,’ because we cannot start by assuming any kind of innate power. Huxley, then, forty years ago, claimed that palaeontologists had proved an orderly succession. To-day we claim to have proved evolution by descent. But how do we prove it? The neontologist, for all his experimental breeding, has scarcely demonstrated the transmutation of a species. The palaeontologist cannot assist at even a single birth. The evidence remains circumstantial. Recapitulation as Proof of Descent. Circumstantial evidence is convincing only if inexplicable on any other admissible theory. Such evidence is, I believe, afforded by palaeontological instances of Haeckel’s law—1.e., the recapitulation by an individual during its growth of stages attained by adults in the previous history of the race. You all know how this has been applied to the ammonites ; but any creatures with a shell or skeleton that grows by successive additions and retains the earlier stages unaltered can be studied by this method. If we take a chronological series of apparently related species or mutations, a’, a?, a°, a*, and if in a* we find that ' the growth stage immediately preceding the adult resembles the adult a*, and that the next preceding stage resembles a?, and so on; if this applies mutatis mutandis to the other species of the series; and if, further, the old age of each species foreshadows the adult character of its successor; then we are entitled to infer that the relation between the species is one of descent. Mistakes are liable to occur for various reasons, which we are learning to guard against. For example, the perennial desire of youth to attain a semblance of maturity leads often to the omission of some steps in the orderly process. But this and other eccentricities affect the earlier rather than the later stages, so that it is always possible to identify the immediate ancestor, if it can be found. Here we have to remember that the ancestor may not have lived in the same locality, and that therefore a single cliff-section does not always provide a complete or simple series. An admirable example of the successful search for a father is provided by R. G. Carruthers in his paper on the evolution of Zaphrentis delanouei (1910, Quart. Journ. Geol, Soc., lxvi., 523). Surely when we get a clear case of this kind we are entitled to use the word ‘ proof,’ and to say that we have not merely observed the succession, but have proved the filiation. _ It has, indeed, been objected to the theory of recapitulation that the stages of individual growth are an inevitable consequence of an ¥3 68 SECTIONAL ADDRESSES. animal’s gradual development from the embryo to the adult, and there- fore prove nothing. Even now there are those who maintain that the continuity of the germ-plasm is inconsistent with any true recapitula- tion. Let us try to see what thismeans. Take any evolutionary series, and consider the germ-plasm at any early stage in it. The germ, it is claimed, contains the factors which produce the adult characters of that stage. Now proceed to the next stage of evolution. The germ has either altered or it has not. If it has not altered, the new adult characters are due to something outside the germ, to factors which may be in the environment but are notin the germ. In this case the animal must be driven by the inherited factors to reproduce the ancestral form ; the modifications due to other factors will come in on the top of this, and if they come in gradually and in the later stages of growth, then there will be recapitulation. There does not seem to be any difficulty here. You may deny the term ‘ character’ to these modifications, and you may say that they are not really inherited, that they will disappear entirely if the environment reverts to its original condition. Such lan- guage, however, does not alter the fact, and when we pass to subsequent stages of evolution and find the process repeated, and the recapitulation becoming longer, then you will be hard put to it to imagine that the new environment produces first the effects of the old and then its own particular effect. Even if we do suppose that the successive changes in, say, an ammonite as it passes from youth to age are adaptations to successive environments, this must mean that there is a recapitulation of environ- ment. If is an explanation of structural recapitulation, but the fact remains. There is no difficulty in supposing an individual to pass through the same succession of environments as were encountered in the past history of its race. Every common frog is an instance. . The phenomenon is of the same nature as the devious route followed in their migrations by certain birds, a route only to be explained as the repetition of past history. There are, however, many cases, especially among sedentary organisms, which cannot readily be explained in this way. Let us then examine the other alternative and suppose that every evolutionary change is due to a change in the germ—how produced we need not now inquire. Then, presumably, it is claimed that at each stage of evolution the animal will grow from the egg to the adult along a direct path. For present purposes we ignore purely larval modifications, and admit that the claim appears reasonable. The trouble is that it does not harmonise with facts. The progress from youth to age is not always a simple advance. The creature seems to go out of its way to drag in a growth-stage that is out of the straight road, and can be ex- plained only by the fact that it is inherited from an ancestor. Thus, large ammonites of the Xipheroceras planicosta group, beginning smooth, pass through a ribbed stage, which may be omitted, through unituberculate and bituberculate stages, back to ribbed and smooth again. The anal plate of the larval Antedon, which ends its course and finally disappears above the limits of the cup, begins life in that lower position which the similar plate occupied in most of the older crinoids. we % ‘C.—GEOLOG Y. 69 Here, then, is a difficulty. It can be overcome in two ways. A view held by many is that there are two kinds of characters: first, those fhat arise from changes in the germ, and appear as sudden or discon- tinuous variations; second, those that are due to external (i.e., non- germinal) factors. It seems a corollary of this view that the external characters should so affect the germ-plasm as ultimately to produce in it the appropriate factors. This is inheritance of acquired characters. The other way out of the difficulty is to suppose that all characters other than fluctuations or temporary modifications are germinal; that changes are due solely to changes in the constitution of the germ; and that, although a new character may not manifest itself till the creature has reached old age, nevertheless it was inherent in the germ and latent through the earlier growth-stages. This second hypothesis involves two further difficulties. It is not easy to formulate a mechanism by which a change in the constitution of the germ shall produce a character of which no trace can be detected until old age sets in; such acharacter, for instance, as the tuberculation of the last-formed portion of an ammonite shell. Again, it is generally maintained that characters due to this change of germinal factors, however minute they may be, make a sudden appearance. They are said to be discontinuous. They act as integral units. Now the characters we are trying to explain seem to us palaeontologists to appear very gradually, both in the individual and in the race. Their beginnings are small, scarcely perceptible; they increase gradually in size or strength; and gradually they appear at earlier and earlier stages in the life-cycle. It appears least difficult to suppose that characters of this kind are not initiated in the germ, and that they, if no others, may be subject to recapitulation. It may not yet be possible to visualise the whole process by which such characters are gradually established, or to refer the phenomena of recapitulation back to more fundamental principles. But the phenomena are there, and if any hypothesis is opposed to them so much the worse for the hypothesis. However they be explained, the instances of recapitula- tion afford convincing proof of descent, and so of genetic evolution. The ‘ Line upon Line’ Method of Palaeontology. You will have observed that the precise methods of the modern palaeontologist, on which this proof is based, are very different from the slap-dash conclusions of forty years ago. The discovery of Archae- opteryx, for instance, was thought to prove the evolution of Birds from Reptiles. No doubt it rendered that conclusion extremely probable, especially if the major premiss—that evolution was the method of nature—were assumed. But the fact of evolution is precisely what men were then trying to prove. These jumpings from Class to Class or from Era to Era, by aid of a few isolated stepping-stones, were what Bacon calls Anticipations, ‘ hasty and premature ’ but ‘ very effective, because as they are collected from a few instances, and mostly from those which are of familiar occurrence, they immediately dazzle the intellect and fill the imagination ’ (Nov. Org. I. 28). No secure step was taken until the modern palacontologist began to affiliate mutation with mutation and species with species, working his way back, literally 70 | SECTIONAL ADDRESSES. inch by inch, through a single small group of strata. Only. thus could he base on the laboriously collected facts a single true Interpretation ; and to. those who preferred the broad path of generality his Interpreta- tions seemed, as Bacon says they always ‘must. seem, harsh and discordant—almost like mysteries of faith.’ It is impossible to read these words without thinking of one ‘naturae minister et interpres,’ whose genius was the first in_ this country to appreciate and apply to palaeontology the Novum Organon. Devoting his whole life to abstruse research, he has persevered with this method in the face of distrust and has produced a, series of brilliant studies which, whatever their defects, have illuminated the problems of stratigraphy and gone far to revolutionise systematic palaeontology. Many are the workers of to-day who acknowledge a master in Sydney Savory Buckman. I have long believed that the only safe mode of advance in palae- ontology is that which Bacon counselled and Buckman has practised, namely, ‘ uniformly and step by step.’ Was this not indeed the prin- ciple that guided Linnaeus himself? Not till we have linked species into lineages, can we group them into genera; not till we have un- ravelled the strands by which genus is connected with genus can we draw the limits of families. Not till that has been accomplished can we see how the lines: of descent. diverge or converge, so as to warrant the establishment of Orders. Thus by degrees we reject the old slippery stepping-stones that so often toppled us into the stream, and foot by foot we build a secure bridge over the waters of ignorance. The work is slow, for the material is not always to hand, but as we build we learn fresh principles and test our current hypotheses. To some of these I would now direct your attention. Continuity in Development. Let us look first at this question of continuity. Does an evolving line change by discontinuous steps (saltations), as when a man mounts a ladder; or does it change continuously, as when a wheel rolls up- hill? The mere question of fact is extraordinarily difficult to determine. Considering the gaps in the geological record one would have expected palaeontologists to be the promulgators of the hypothesis of discon- tinuity. They are its chief opponents.‘ The advocates of discon- tinuity maintain that palaeontologists are misled: that the steps are so minute as to escape the observation of workers handicapped by the obscurities of their material; that many apparent characters are com- pound and cannot, in the case of fossils, be subjected to Mendelian 1 As Dr. W. D. Matthew (1910, Pop. Sci. Monthly, p. 473) has well exemplified by the history of the Tertiary oreodont mammals in North America, the known record, taken at its face value, leads to ‘the conclusion that new species, new genera and even larger groups have appeared by saltatory evolution, not by continuous development.’ But a consideration of the general conditions controlling evolution and migration among jand mammals shows him that such a conclusion is unwarranted. ‘The more complete the series of specimens, the more perfect the record in successive strata, and the nearer the hypothetic centre of dispersal, the closer do we come. to a phyletic series whose. intergrading stages are we!] within the limits of observed variation of the race.’ C.— GEOLOGY. TA analysis; that no palaeontologist can guarantee the genetic purity of the assemblages with which he works, even when his specimens are collected from a single locality and horizon. It is difficult to reply to such negative arguments. One can but give examples of the kind of obser- vation on which palaeontologists rely. Since Dr. Rowe’s elaborate analysis of the species of Micraster occurring in the Chalk of $.E. England, much attention has been concentrated on the gradual changes undergone by those sea-urchins in the course of ages. ‘The changes observed affect many characters ; indeed, they affect the whole test, and all parts are doubtless correlated. The changes come in regularly and gradually; there is no sign of discontinuity. It is convenient to give names to the successive forms, but they are linked up by innumerable gradations. There does not seem here to be any question of the sudden appearance of a new character, in one or in many individuals; or of the introduction of any character and the gradual extension of its range by cross-breeding until it has become universal and in turn gives way to some new step in advance. The whole assemblage is affected and moves forward in line, not with an advanced scout here and a straggler there. Slight variation between contemporaneous individuals occurs, no doubt, but the ‘limits are such that a trained collector can tell from a single fossil the level at which it has been found. The continuity of the changes is also inferred from such a fact as that in occasional specimens of Micraster cor-bovis the distinctness of the ambulacral sutures (which is one of these characters) is greater on one side of the test than on the other. Such changes as these may profitably be compared with those which Professor Duerden believes to be taking place in the ostrich. He too finds a slow continuous change affecting innumerable parts of the bird, a change that is universal and within slight limits of variation as between individuals. Even on the hypothesis that every barb of every feather is represented by a factor in the germ, he finds it impossible to regard the changes as other than continuous, and he is driven to the supposition (on the hypothesis of germinal factors) that the factors themselves undergo a gradual change, which he regards as due to old age. It is interesting also that he finds an occasional lop-sided change, such as we noted in Micraster cor-bovis. Whatever may be the explanation, the facts do seem to warrant the statement that evolutionary change can be, and offen is, continuous. Professor De Vries has unfortunately robbed palaeontologists of the word ‘ mutation,’ by which, following Waagen, they were accustomed to denote such change. I propose, therefore, to speak of it as ‘transition.’ But here the question may be posed, whether such transi- tions can progress indefinitely, or whether they should not be compared to those divergences from the norm of a species which we call fluctua- tions, because, like the waves of the sea piled up by a gale, they return to their original level when the external cause is removed. If every apparent transition in time is of the latter nature, then, when it reaches a limit comparable to that circumscribing contemporary fluctuation, there must, if progress is to persist, be some disturbance provoking 72 SECTIONAL ADDRESSES. a saltation, and so giving a new centre to fluctuation and a fresh limit to the upward transition. Those who maintain such an hypothesis presumably regard transition as the response of the growing individual body to gradual change of the physical environment (somatic modifica- tion). But saltation they ascribe to a change in the composition of the germ. That change may be forced on the germ by the condition of the body, and may therefore be in harmony with the environment, and may produce a new form along that line. The new form may be obviously distinct from its predecessor, or the range of its fluctuation may overlap that of its predecessor, in which case it will be impossible to decide whether the change is one of transition or of saltation. This succession of hypotheses involves a good many difficulties; among others, the mechanism by which the germ is suddenly modified in accordance with the transition of the body remains obscure. But the facts before us seem to necessitate either perpetual transition or salta- tion acting in this manner. ‘Transition, we must admit, also involves a change of the germ pari passu with the change of the body. Conse- quently the difference between the two views seems to be narrowed down to a point which, if not trivial, is at any rate minute. The particular saltation-hypothesis which I have sketched may remind some hearers of the ‘ expression points ’ of E. D. Cope. That really was quite a different conception. Cope believed that, in several cases, generic characters, after persisting for a long time, changed with relative rapidity. This took place when the modifications of adult structure were pushed back so far prior to the period of reproduction as to be transmitted to the offspring. The brief period of time during which this rapid change occurred in any genus was an expression-point, and was compared by Cope to the critical temperature at which a gas changes into a liquid, or a liquid into a solid. The analogy is not much more helpful than Galton’s comparison of a fluctuating form to a rocking polyhedron, which one day rocks too much and topples over on to another face. It is, however, useful to note Cope’s opinion that these points were ‘ attained without leaps, and abandoned without abruptness.’ He did not believe that ‘ sports’ had ‘ any considerable influence on the course of evolution ’ (1887, ‘ Origin of Fittest,’ pp. 39, 79; 1896, ‘ Factors Org. Evolution,’ pp. 24, 25). The Direction of Change: Seriation. The conception of connected change, whether by transition or by scarcely perceptible saltation, or by a combination of the two processes, leads us to consider the Direction of the Change. Those who attempt to classify species now living frequently find that they may be arranged in a continuous series, in which each species differs from its neighbours by a little less or a little more; they find that the series corresponds with the geographical distribution of the species; and they find sometimes that the change affects particular genera or families or orders, and not similar assemblages subjected, apparently, to the same conditions. They infer from this that the series represents a genetic relation, that each successive species is the descendant of its preceding neighbour ; and in some cases this inference C.—GEOLOGY. 73 is warranted by the evidence of recapitulation, a fact which further indicates that the change arises by addition or subtraction at the end of the individual life-cycle. So far as I am aware this phenomenon, at least so far as genera are concerned, was first precisely defined by Louis Agassiz in his ‘ Hssay on Classification,’ 1857. He called it ‘ Serial Connection,’ a term which connotes the bare statement of fact. Cope in his ‘ Origin of Genera,’ 1869, extended the observation, in a few cases, to species, and introduced the term ‘ Successional Relation,’ which for him implied descent. We may here use the brief and non-committal term ‘ Seriation.’ The comparison of the seriation of living species and genera to the seriation of a succession of extinct forms as revealed by fossils was, it seems, first definitely made by Cope, who in 1866 held the zoological regions of to-day to be related to one another ‘as the different sub- divisions of a geologic period in time’ (Journ. Acad. Nat. Sct. Phila- delphia, 1866, p. 108). This comparison is of great importance. Had we the seriations of living forms alone, we might often be in doubt as to the meaning of the phenomenon. In the first place we might ascribe it purely to climatic and similar environmental influence, and we should be unable to prove genetic filiation between the species. Even if descent were assumed we should not know which end of the series was ancestral, or even whether the starting point might not be near the middle. But when the palaeontologist can show the same, or even analogous, seriation in a time-succession, he indicates to the neontologist the solution of his problem. Here it is well to remind ourselves that all seriations are not exact. There are seriations of organs or of isolated characters, and the trans- ition has not always taken place at the same rate. Hence numerous examples of what Cope called Inexact Parallelism. The recognition of such cases is largely responsible for the multiplication of genera by some modern palaeontologists. This may or may not be the best way of expressing the facts, but it is desirable that they should be plainly expressed or we shall be unable to delineate the actual lines of genetic descent. Restricting ourselves to series in which descent may be considered as proved or highly probable, such as the Micrasters of the Chalk, we find then a definite seriation. There is not merely transition, but trans- ition in orderly sequence such as can be represented by a graphic curve of simple form. If there are gaps in the series as known to us, we can safely predict their discovery ; and we can prolong the curve backwards or forwards, so as to reveal the nature of ancestors or descendants. Orthogenesis: Determinate Variation. The regular, straightforward character of such seriation led Eimer to coin the term Orthogenesis for the phenomenon as a whole. If this term be taken as purely descriptive, it serves well enough to denote certain facts. But Orthogenesis, in the minds of most people, connotes the idea of necessity, of determinate variation, and of predetermined course. Now, just as you may have succession without evolution, so you may have seriation without determination or predetermination. 74 SECTIONAL ADDRESSES. Let us be clear as to the meaning of these terms. | Variation is said to be determinate, or, as Darwin called it, ‘ definite,’ when all the offspring vary in the same direction. Such definite variation may be determined by a change in the composition of the germ, due perhaps to some external influence acting on all the parents; or it may express the direct action of an external influence on the growing offspring. The essential feature is that all the changes are of the same kind, though they may differ in degree. For instance, all may consist in some addi- tion, as a thickening of skeletal structures, an outgrowth of spines or horns; or all may consist in some loss, as the smaller size of outer digits, the diminution of tubercles, or the disappearance of feathers. A succession of such determinate variations for several generations pro- duces seriation ; and when the seriation is in a plus direction it is called progressive (anabatic, anagenetic), when in a minus direction, retro- gressive (catabatic, catagenetic). When successive additions appear late in the life-cycle, each one as it were pushing its predecessors back to earlier stages, then we use Cope’s phrase—acceleration of develop- ment. When subtraction occurs in the same way, there is retardation of development. Now it is clear that if a single individual or genera- tion produces offspring with, say, plus variations differing in degree, then the new generation will display seriation. Instances of this are well known. You may draw from them what inferences you please, but you cannot actually prove that there is progression. Breeding- experiments under natural conditions for a long series of years would be required for such proof. Here, again, the palaeontologist can point to the records of the process throughout centuries or millennia, and can show that there has been undoubted progression and retrogression. I do not mean to assert that the examples of progressive and retrogres- sive series found among fossils are necessarily due to the seriation of determinate variations ; but the instances of determinate variation known among the creatures now living show the palaeontologist a method that may have helped to produce his series. Once more the observations of neontologist and palaeontologist are mutually complementary. Predetermination. So much for determination: now for Predetermination. This is a far more difficult problem, discussed when the fallen angels * reasoned high Of providence, foreknowledge, will, and fate, Fixed fate, free will, foreknowledge absolute, And found no end in wandering mazes lost.’ —and it is likely to be discussed so long as a reasoning mind persists. For all that, it is a problem on which many palaeontologists seem to have made up their minds. They agree (perhaps unwittingly) with Aristotle * that ‘Nature produces those things which, being con- * pioer yap [ylvovra] boa ad Tivos ev abtois dpxiis ouvexas kwotmeva aikverra els tt TéAos. Phys, Il., 199b, 15, ed. Bekker. C.— GEOLOGY. "5 tinuously moved by a certain principle inherent in themselves, arrive at a certain end.’ In other words, a race once started on a certain course, will persist in that course; no matter how conditions may change, no matter how hurtful to the individual its own changes may be, progressive or retrogressive, up hill and down hill, straight as a Roman road, it will go on to that appointed end. Nor is it only palaeontologists who think thus. Professor Duerden has recently written, ‘The Nagelian idea that evolutionary changes have taken place as a result of some internal vitalistic force, acting altogether independently of external influences, and proceeding along definite lines, irrespective of adaptive considerations, seems to be gaining ground at the present time among biologists ’ (1919, Journ, Genetics, vii. p. 193). The idea is a taking one, but is it really warranted by the facts at our disposal? We have seen, I repeat, that succession does not imply evolution, and (granting evolution) I have claimed that seriation can occur without determinate variation and without predetermination. It is easy to see this in the case of inanimate objects subjected to a con- trolling foree. The fossil-collector who passes his material through a series of sieves, picking out first the larger shells, then the smaller, and finally the microscopic foraminifera, induces a seriation in size by an action which may be compared to the selective action of successive environments. ‘There is, in this case, predetermination imposed by an external mind; but there is no determinate variation. You may see in the museum at Leicester a series beginning with the via strata of the Roman occupants of Britain, and passing through all stages of the tramway up to the engineered modern railroad. The unity and apparent inevitability of the series conjures up the vision of a world- mind consciously working to a foreseen end. An occasional experiment along some other line has not been enough to obscure the general trend ; indeed, the speedy scrapping of such failures only emphasises the idea of a determined plan. But closer consideration shows that the course of the development was guided simply by the laws of mechanics and economies, and by the history of discovery in other branches of science. That alone was the nature of the determination; and predetermination, there was none. From these instances we see that selection can, indeed must, produce just that evolution along definite lines which is the supposed feature of orthogenesis. The arguments for orthogenesis are reduced to two: first, the diff- culty of accounting for the incipient stages of new structures before they achieve selective value; second, the supposed cases of non-adaptive or even—as one may term it—counter-adaptive growth. The earliest discernible stage of an entirely new character in an adaptive direction is called by H. F. Osborn a ‘ rectigradation ’ (1907), and the term implies that the character will proceed to develop in a definite direction. As compared with changes of proportion in exist- ing characters (‘ allometron,’ Osborn), rectigradations are rare. Osborn applies the term to the first signs of folding of the enamel in the teeth of the horse. Another of his favourite instances is the genesis of horns in the Titanotheres, which he has summarised as follows: ‘ (a) from excessively rudimentary beginnings, i.e. rectigradations, which can 76 SECTIONAL ADDRESSES. hardly be detected on the surface of the skull; (b) there is some pre- determining law or similarity of potential which governs their first existence, because (c) the rudiments arise independently on the same part of the skull in different phyla [i.e. lineages] at different periods of geologic time; (d) the horn rudiments evolve continuously, and they gradually change in form (i.e. allometrons) ; (e) they finally become the dominating characters of the skull, showing marked variations of the form in the two sexes; (f) they first appear in late or adult stages of ontogeny, but are pushed forward gradually into earlier and earlier ontogenetic stages until they appear to arise prenatally.’ Osborn says that rectigradations are a result of the principle of determination, but this does not seem necessary. In the first place, the precise distinction between an allometron and a rectigradation fades away on closer scrutiny. When the rudiment of a cusp or a horn changes its form, the change is an allometron; the first swelling is a rectigradation. But both of these are changes in the form of a pre- existing structure; there is no fundamental difference between a bone with an equable curve and one with a slight irregularity of surface. Why may not the original modification be due to the same cause as the succeeding ones? The development of a horn in mammalia is prob- ably a response to some rubbing or butting action which produces changes first in the hair and epidermis. One requires stronger evidence than has yet been adduced to suppose that in this case form precedes function. As Jaekel has insisted, skeletal formation follows the changes in the softer tissues as they respond to strains and stresses. In the evolution of the Echinoid skeleton, any new structures that appear, such as auricles for the attachment of jaw-muscles or notches for the reception of external gills, have at their inception all the character of rectigradations, but it can scarcely be doubted that they followed the growth of their correlated soft parts, and that these latter were already subject to natural selection. But we may go further: in vertebrates as in echinoderms the bony substance is interpenetrated with living matter, which renders it directly responsive to every mechanical force, and modifies it as required by deposition or resorption, so that the skeleton tends continually to a correlation of all its parts and an adapta- tion to outer needs. The fact that similar structures are developed in the same positions in different stocks at different periods of time is paralleled in probably all classes of animals; Ammonites, Brachiopods, Polyzoa, Crinoids, Sea- urchins present familiar instances. But do we want to make any mystery of it? The words ‘predisposition,’ ‘ predetermining law,’ ‘similarity of potential,’ ‘inhibited potentiality,’ and ‘ periodicity,’ all tend to obscure the simple statement that like causes acting on like material produce like effects. When other causes operate, the result is different. Certainly such facts afford no evidence of predetermination, in the sense that the development must take place willy-nilly. Quite the contrary: they suggest that it takes place only under the influence of the necessary causes. Nor do they warrant such false analogies as ‘ Environment presses the button: the animal does the rest.’ The resemblance of the cuttle-fish eye to that of a vertebrate has yy C.— GEOLOGY. i7 been explained by the assumption that both creatures are descended, longo intervallo no doubt, from a common stock, and that the flesh or the germ of that stock had the internal impulse to produce this kind of eye some day when conditions should be favourable. It is not ex- plained why many other eyed animals, which must also have descended from this remote stock, have developed eyes of a different kind. Never- theless I commend this hypothesis of Professor Bergson to the advo- eates of predisposition. To my mind it only shows that a philosopher may achieve distinction by a theory of evolution without a secure know- ledge of biology. When the same stock follows two quite different paths to the same goal, it is impossible to speak of a predetermined course. In the Wen- lock beds is a crinoid whose stalk has become flattened and coiled, and the cirri or tendrils of the stalk are no longer set by fives all round it, but are reduced to two rows, one along each side. In one species these cirri are spaced at irregular intervals along the two sides, but as the animal grows there is a tendency for them to become more closely set. In another species, in various respects more developed, the cirri are set quite close together, and the tightly coiled stalk looks like a ribbed ammonite. Closer inspection shows that this species includes two distinct forms. In one each segment of the stalk bears but a single cirrus, first on the right, then on the left; but the segments taper off to the opposite side so that the cirri are brought close together. In the other form two cirri are borne by a single segment, but the next segment bears no cirri. These intervening segments taper to each side, so that here also the cirri are brought close together. Thus the same appearance and the same physiological effect are produced in two distinct ways. Had one ofthese never existed, the evolution of this curious stem would have offered as good an argument for orthogenesis as many that have been advanced. So much for similarity ! The argument for orthogenesis based on a race-history that marches to inevitable destruction, heedless of environmental factors, has always seemed to me incontrovertible, and so long as my knowledge of palaeontology was derived mainly from books I accepted this premiss as well founded. Greater familiarity with particular groups has led me to doubt whether such cases really occur, for more intensive study generally shows that characters at first regarded as indifferent or detrimental may have been adapted to some factor in the environment or some peculiar mode of life. Professor Duerden’s jnteresting and valuable studies of the ostrich (1919, 1920, Journ. Genetics) lead him to the opinion that retrogressive changes in that bird are destined to continue, and ‘ we may look for- ward,’ he says, ‘ to the sad spectacle of a wingless, legless, and feather- less ostrich if extinction does not supervene.’ Were this so we might at least console ourselves with the thought that the process is a very slow one, for Dr. Andrews tells me that the feet and other known bones of a Pliocene ostrich are scarcely distinguishable from those of the present species. But, after careful examination of Dr. Duerden’s arguments, I see no ground for supposing that the changes are other than. adaptive. Similar changes.occur in other birds of other stocks 78 SECTIONAL ADDRESSES. when subjected to the requisite conditions, as the flightless birds of diverse origin found on ocean islands, the flightless and running rails, geese, and other races of New Zealand, the Pleistocene Genyornis of the dried Lake Callabonna, which, as desert conditions came on, began to show a reduction of the inner toe. Among mammals the legs and feet have been modified in the same way in at least three distinct orders or suborders, during different periods, and in widely separated regions, Living marsupials in Australia have the feet modified accord- ing to their mode of life, whether climbing on trees or running over hard ground; and among the latter we find a series indicating how the outer toes were gradually lost and the fourth digit enlarged. 1 need scarcely remind you of the modifications that resulted in the horse’s hoof with its enlarged third digit, traceable during the Tertiary Epoch throughout the Northern Hemisphere, whether in one or more than one stock. I would, however, recall the fact that occasional races, resuming from time to time a forest habitat, ceased to progress along the main line. Lastly, there are those early hoofed animals from South America, made known by Ameghino under the name Litopterna, which underwent a parallel series of changes and attained in Thoatherium from the Upper Miocene of Patagonia a one-toed foot with elongate metacarpals essentially similar to that of the horse. In all these cases the correlation of foot-structure with mode of life (as also indicated by the teeth) is such that adaptation by selection has always been regarded as the sole effective cause. My colleague, Dr. W. D. Lang, has recently published a most thoughtful paper on this subject (1919, Proc. Geol. Assoc. xxx. 102). His profound studies on certain lineages of Cretaceous Polyzoa (Cheilostomata) have led him to believe that the habit of secreting calcium carbonate, when once adopted, persists in an increasing degree. Thus in lineage after lineage the habit ‘has led to a brilliant but comparatively brief career of skeleton-building, and has doomed the organism finally to evolve but the architecture of its tomb.’ These creatures, like all others which secrete calcium carbonate, are simply suffering from a gouty diathesis, to which each race will eventually succumb. Meanwhile the organism does its best to dispose of the secretion ; if usefully, so much the better; but at any rate where it will be least in the way. Some primitive polyzoa, we are told, often sealed themselves up; others escaped this self-immurement by turning the excess into spines, which in yet other forms fused into a front wall. But the most successful architects were overwhelmed at last by superabundance of building-material. _.__ While sympathetic to Dr. Lang’s diagnosis of the disease (for in 1888 I hazarded the view that in Cephalopoda lime-deposition was uncontrollable by the animal, and that its extent was inversely relative to the rate of formation of chitin or other calcifiable tissue), still I think he goes too far in postulating an ‘insistent tendency.’ He speaks of living matter as if it were the over-pumped inner-tube of a bicycle tyre, ‘tense with potentiality, curbed by inhibitions’ fof the cover] and ‘ periodically breaking out as inhibitions are removed ’ {by broken glass]. A race acquires the lime habit or the drink habit, 0.—GEOLOGY, 79 and, casting off all restraint, rushes with accelerated velocity down the easy slope to perdition. A melancholy picture! But is it true? The facts in the case of the Cretaceous Polyzoa are not disputed, but they can be’ interpreted as a reaction of the organism to the continued abundance of lime-salts in the sea-water. If a race became choked off with lime, this perhaps was because it could not keep pace with its environment. Instead of ‘irresistible momentum’ from within, we may speak of irresistible pressure from without. Dr. Lang has told us (1919, Phil. Trans. B. ecix.) ‘that in their evolution the individual characters in a lineage are largely independent of one another.’ It is this independ- ence, manifested in differing trends and differing rates of change, that originates genera and species. Did the evolution follow some inner impulse, along lines ‘ predetermined and limited by innate causes,’ one would expect greater similarity, if not identity, of pattern and of tempo. Many are the races which, seeking only ornament, have (say our historians) perished like Tarpeia beneath the weight of a less welcome cift: oysters, ammonites, hippurites, crinoids, and corals. But I see no reason to suppose that these creatures were ill-adapted to their erivironment—until the situation changed. This is but a special case of increase in size. In creatures of the land probably, and in creatures of the water certainly (as exemplified by A. D. Mead’s experiments on the starfish, 1900, Amer. Natural. xxxiv. 17), size depends on the amount of food, including all body- and skeleton-building con- stituents. When food is plentiful larger animals have an advantage over small. Thus by natural selection the race increases in size until a balance is reached. Then a fall in the food-supply handicaps the larger creatures, which may become extinct. So simple an explana- tion renders it quite unnecessary to regard size as in itself indicating the old age of the race. Among the structures that have been most frequently assigned to some blind growth-force are spines or horns, and when they assume a grotesque form or disproportionate size they are dismissed as evidences of senility. Let us take a case. The Trilobite family Lichadidae is represented in Ordovician and Silurian rocks by species with no or few spines, but in the early part of the Devonian, both in America and in Europe, various unrelated groups in this family begin to grow similarly formed and situated spines, at first short and straight, but soon becoming long curved horns, until the climax is reached in such a troll-like goat-form as Ceratarges armatus of the Calceola-beds in the Hifel. Dr. J. M. Clarke (1913, Monogr. Serv. Geol. Brazil, i. p. 142) is among those who have regarded this parallel development as a sign of orthogenesis in the most mystical meaning of the term. Strange though these little monsters may be, I cannot, in view of their con- siderable abundance, believe that their specialisation was of no use to them, and I am prepared to accept the following interpretation by Dr. Rudolf Richter (1919, 1920). Such spines haye their first origin in the tubercles which form so 80 SECTIONAL ADDRESSES. common an ornament in Crustacea and other Arthropods and which serve to stiffen the carapace. A very slight projection of any of these tubercles further acts as a protection against such soft-bodied enemies as jelly-fish. Longer out-growths enlarge the body of the trilobite in such a way as to prevent its being easily swallowed. When, as is often the case, the spines stretch over such organs as the eyes, their protective function is obvious. This becomes still more clear when we consider the relation of these spines to the body when rolled up, for then they are seen to form an encircling or enveloping chevauz- de-frise. But besides this, the spines in many cases serve as balancers ; they throw the centre of gravity back from the weighty head, and thus enable the creature to rise into a swimming posture. Further, by their friction, they help to keep the animal suspended in still water with a comparatively slight motion of its numerous oar-like limbs. Regarded in this light, even the most extravagant spines lose their mystery and appear as consequences of natural selection. A com- parison of the curious Marrella in the pelagic or still-water fauna of the Middle Cambrian Burgess shale with Acidaspis radiata of the Calceola-beds certainly suggests that both of these forms were adapted to a similar life in a similar environment. The fact that many extreme developments are followed by the extinction of the race is due to the difficulty that any specialised organism or machine finds in adapting itself to new conditions. A highly specialised creature is one adapted to quite peculiar circumstances; very slight external change may put it out of harmony, especially if the change be sudden. It is not necessary to imagine any decline of vital force or exhaustion of potentiality. When people talk of certain creatures, living or extinct, as obviously unadapted for the struggle of life, I am reminded of Sir Henry de Ja Beche’s drawing of a lecture on the human skull by Professor Ichthyosaurus. ‘ You will at once perceive,’ said the lecturer, ‘ that the skull before us belonged to one of the lower orders of animals; the teeth are very insignificant, the power of the jaws trifling; and altogether it seems wonderful how the creature could have procured food.’ What, then, is the meaning of ‘momentum’ jn evolution? Simply this, that change, whatever its cause, must be a change of something that already exists. The changes in evolving lineages are, as a rule, orderly and continuous (to avoid argument the term may for the moment include minute saltations). Environment changes slowly and the response of the organism always lags behind it, taking small heed of ephemeral variations.” Suppose a change from shallow to deep water 2 The conception of dag in evolution is of some importance. On a hypothesis of selection from fortuitous variations the lag must be considerable. If the variations be determinate and in the direction of the environmental change, the lag will be reduced; but according as the determination departs from the environmental change, the lag will increase. If a change of environment acts on the germ, inducing either greater variation or variation in harmony with the change, there will still be lag, but it will be less. On this hypothesis the lag will depend on the mechanism through which the environment affects the germ. If, with Osborn, we imagine an action on the body, transmitted to the various C.—GEOLOGY. 81 —either by sinking of the sea-floor or by migration of the organism. Creatures already capable of becoming acclimatised will be the majority of survivors, and among them those which change most rapidly will soon dominate. Place your successive forms in order, and you will get the appearance of momentum; but the reality is inertia yielding with more or less rapidity to an outer force. Sometimes a change is exhibited to a greater or less extent by every member of some limited group of animals, and this change may seem to be correlated with the conditions of life in only a few of the genera or species, while in others it manifests no adaptive character and no selective value. Thus the loss of the toes or even limbs in certain lizards is ascribed by Dr. G. A. Boulenger to an internal tendency, although, at any rate in the Skinks, which furnish examples of all stages of loss, it certainly seems connected with a sand-loving and burrowing life. Recently Dr. Boulenger (1920, Bull. Soc. Zool. France, xlv. 68) has put forward the East African Testudo loveridgei, a ribless tortoise with soft shell that squeezes into holes under rocks, and swells again like an egg in a bottle, as the final stage of a regressive series. The early stages of this regression, such as a decrease in size of the vertebral processes and rib-heads, were long since noticed by him in other members of the same family; but, since they did not occur in other families, and since he could perceive no adaptive value in them, he regarded them as inexplicable, until this latest discovery proved them to be prophetic of a predestined goal. The slightness of my acquaint- ance with tortoises forbids me to controvert this supreme example of teleology as it appears to so distinguished an authority. But in all these apparent instances we should do well to realise that we are still incompletely informed about the daily life of these creatures and of their ancestors in all stages of growth, and we may remember that structures once adaptive often persist after the need has passed or has been replaced by one acting in a different direction. The Study of Adaptive Form. This leads us on to consider a fruitful field of research, which would at first seem the natural preserve of neontologists, but which, as it happens, has of late been cultivated mainly to supply the needs of palaeontology. That field is the influence of the mode of life on the shape of the creature, or briefly, of function on form; and, conversely, the indications that form can give as to habits and habitat. For many a long year the relatively simple mechanics of the vertebrate skeleton have been studied by palaeontologists and anatomists generally, and have been brought into discussions on the effect of use. The investiga- tion of the mechanical conditions controlling the growth of organisms has recently been raised to a higher plane by Professor D’Arcy Thompson’s parts through catalysera and hormones, then the process will involve lag varying with the physico-chemical constitution of the organism. Slight differences in this respect between different races may have some bearing on the rate of change (vide infra ‘The Tempo of Evolution’), on the correlation of characters, and so on the diversity of form. 1920 q 82 SECTIONAL ADDRESSES. suggestive book on ‘ Growth and Form.’ These studies, however, have usually considered the structure of an animal as an isolated machine, We have to realise that an organism should be studied in relation to the whole of its environment, and here form comes in as distinct from structure. That mode of expression, though loose and purely relative, will be generally understood. By ‘form’ one means those adaptations to the surrounding medium, to food, to the mode of motion, and so forth, which may vary with outer conditions while the fundamental structure persists. Though all structures may, conceiy- ably, have originated as such adaptations, those which we call ‘ form’ are, as a rule, of later origin. Similar. adaptive forms are found in organisms of diverse structure, and produce those similarities which we know as ‘ convergence.’ To take but one simple instance from the relations of organisms to gravity. A stalked echinoderm naturally grows upright, like a flower, with radiate symmetry. But in the late Ordovician and in Silurian rocks are many in which the body has a curiously flattened leaf-like shape, in which the two faces are distinct, but the two sides alike, and in which this effect is often enhanced by paired outgrowths corresponding in shape if not in structure. Expan- sion of this kind implies a position parallel to the earth’s surface, .7.e. at right angles to gravity. The leaf-like form and the balancers are adaptations to this unusual position. Recognition of this enables us to interpret the peculiar features of each genus, to separate the adaptive form from the modified structure, and to perceive that many genera outwaraly similar are really of quite different origin. Until we understand the principles governing these and other adapta- tions—irrespective of the systematic position of the creatures in which they appear—we cannot make adequate reconstructions of our fossils, we cannot draw correct inferences as to their mode of life, and we cannot distinguish the adaptive from the fundamental characters. No doubt many of us, whether palaeontologists or neontologists, have long recog- nised the truth in a general way, and have attempted to describe our material—whether in stone or in aleohol—as living creatures; and not as isolated specimens but as integral portions of a mobile world. It is, however, chiefly to Louis Dollo that we owe the suggestion and the example of approaching animals primarily from the side of the environ- ment, and of studying adaptations as such. The analysis of adaptations in those casés where the stimulus can be recognised and correlated with its reaction (as in progression through different media or over different surfaces) affords sure ground for inferences concerning similar forms of whose life-conditions we are ignorant. Thus Othenio Abel (1916) has analysed the evidence as to the living squids and cuttle-fish and has applied it to the belemnites and allied fossils with novel and interesting results. But from such analyses there have been drawn wider con- clusions pointing to further extension of the study. It was soon seen that adaptations did not come to perfection all at once, but that har- monisation was gradual, and that some species had progressed further than others. But it by no means follows that these represent chains of descent. The adaptations of all the organs must be considered, and one seriation checked by another. Thus in 1890, in sketching the probable 0.— GEOLOGY. 83 history of certain crinoids, I pointed out that the seriation due to the migration of the anal plates must be checked by the seriation due to the elaboration of arm-structure, and so on. . In applying these principles we are greatly helped by Dollo’s thesis of the Irreversibility of Evolution. It is not necessary to regard this as an absolute Law, subject to no conceivable exception. It is a simple statement of the facts as hitherto observed, and may be expressed thus: 1. In the course of race-history an organism never returns exactly to its former state, even if placed in conditions of existence identical with those through which it has previously passed. Thus, if through adap- tation to a new mode of life (as from walking to climbing) a race loses organs which were highly useful to it in the former state, then, if it ever reverts to that former mode of life (as from climbing to walking), those organs never return, but other organs are modified to take their place. 2. But (continues the Law), by virtue of the indestructibility of the past, the organism always preserves some trace of the intermediate stages. Thus, when a race reverts to its former state, there remain the traces of those modifications which its organs underwent while it was pursuing another mode of existence. The first statement imposes a veto on any speculations as to descent that involve the reappearance of a vanished structure. It does not interfere with the cases in which old age seems to repeat the characters of youth, as in Ammonites, for here the old-age character may be similar, but obviously is not the same. The second statement furnishes a guide to the mode of life of the immediate ancestors, and is applicable to living as well as to fossil forms. It is from such persistent adaptive characters that some have inferred the arboreal nature of our own ancestors, or even of the ancestors of all mammals. ‘To take but a single point, Dr. W. D. Matthew (1904, Amer. Natural. xxxyiil. 813) finds traces of a former opposable thumb in several early Eocene mammals, and features dependent on this in the same digit of all mammals where it is now fixed, The Study of Habitat. The natural history of marine invertebrata is of particular interest to the geologist, but its study presents peculiar difficulties. The marine zoologist has long recognised that his early efforts with trawl and dredge threw little light on the depth in the sea frequented by his captures. The surface floaters, the swimmers of the middle and lower depths, and the crawlers on the bottom were confused in a single haul, and he has therefore devised means for exploring each region separately. The geologist, however, finds all these faunas mixed in a single deposit. He may even find with them the winged creatures of the air, as in the insect beds of Gurnet Bay, or the remains of estuarine and land animals. Such mixtures are generally found in rocks that seem to have been deposited in quiet land-locked bays. Thus in a Silurian rock near Visby, Gotland, have been found creatures of such diverse habitat as a scorpion, a possibly estuarine Pterygotus, a large barnacle, and a _ erinoid of the delicate form usually associated with clear deep water. a 2 84 SECTIONAL. ADDRESSES. The lagoons of Solenhofen have preserved a strange mixture of land and sea life, without a trace of fresh or brackish water forms. Archae- opteryx, insects, flying reptiles, and creeping reptiles represent the air and land fauna; jelly-fish and the crinoid Saccocoma are true open- water wanderers; sponges and stalked crinoids were sessile on the bottom; starfish, sea-urchins, and worms crawled on the sea-floor ; king-crabs, lobsters, and worms left their tracks on mud-flats ; cephalo- pods swam at various depths; fishes ranged from the bottom mud to the surface waters. The Upper Ordovician Starfish bed of Girvan contains not only the crawling and wriggling creatures from which it takes its name, but stalked echinoderms adapted to most varied modes of life, swimming and creeping trilobites, and indeed representatives of almost all marine levels. In the study of such assemblages we have to distinguish palieen the places of birth, of life, of death, and of burial, since, though these may all be the same, they may also be different. The echinoderms of the Starfish bed further suggest that closer discrimination is needed between the diverse habitats of bottom forms. Some of these were, I believe, attached to sea-weed; others grew up on stalks above the bottom ; others clung to shells or stones; others lay on the top of the sea-floor ; others were partly buried beneath its muddy sand; others may have grovelled beneath it, connected with the overlying water by passages. Here we shall be greatly helped by the investigations of C. G. J. Petersen and his fellow-workers of the Danish Biological Station. (See especially his summary, ‘The Sea Bottom and its Production of Fish Food,’ Copenhagen, 1918.) They have set an example of intensive study which needs to be followed elsewhere. By bringing up slabs of the actual bottom, they have shown that, even in a small area, many diverse habitats, each with its peculiar fauna, may be found, one superimposed on the other. Thanks to Petersen and similar investigators, exact comparison can now take the place of in- genious speculation. And that this research is not merely fascinating in itself, but illuminatory of wider questions, follows from the con- sideration that analysis of faunas and their modes of life must be a necessary preliminary to the study of migrations and geographical distribution. The Tempo of Evolution. We have not yet done with the results that may flow from an analysis of adaptations. Among the many facts which, when considered from the side of animal structure alone, lead to transcendental theories with Greek names, there is the observation that the relative rate of evolution is very different in races living at the same time. Since their remains are found often side by side, it is assumed that they were subject to the same conditions, and that the differences of speed must be due to a difference of internal motive force. After what has just been said you will at once detect the fallacy in this assumption. Professor Abel has recently maintained that the varying tempo of evolution depends on the changes in outer conditions. He compares the evolution of whales, sirenians, and horses during the Tertiary Epoch, and correlates it with 0.—a@koLoey. 85 the nature of the food. Roughly to summarise, he points out that from the Eocene onwards the sirenians underwent a steady, slow change, because, though they migrated from land to sea, they retained their habit of feeding on the soft water-plants. The horses, though they remained on land, display an evolution at first rather quick, then slower, but down to Pliocene times always quicker than that of the sirenians ; and this is correlated with their change into eaters of grain, and their adaptation to the plains which furnish such food. The whales, like the sirenians, migrated at the beginning of the Tertiary from land to sea; but how different is their rate of evolution, and into what diverse forms have they diverged! At first they remained near the coasts, keep- ing to the ancestral diet, and, like the sirenians, changing but slowly. But the whales were flesh-eaters, and soon they took to hunting fish, and then to eating large and small cephalopods; hence from the Oligocene onwards the change was very quick, and in Miocene times the evolution was almost tempestuous. Finally, many whales turned to the swallow- ing of minute floating organisms, and from Lower Pliocene times, having apparently exhausted the possibilities of ocean provender, they changed with remarkable slowness. Whether such changes of food or of other habits of life are, in a sense, spontaneous, or whether they are forced on the creatures by changes of climate and other conditions, makes no difference to the facts that the changes of form are a reaction to the stimuli of the outer world, and that the rate of evolution depends on those outer changes. Whether we have to deal with similar changes of form taking place at different times or in different places, or with diverse changes affect- ing the same or similar stocks at the same time and place, we can see the possibility that all are adaptations to a changing environment. There is then reason for thinking that ignorance alone leads us to assume some inexplicable force urging the races this way or that, to so-called advance or to apparent degeneration, to life or to death. The Rhythm of Life. The comparison of the life of a lineage to that of an individual is, up to a point, true and illuminating; but when a lineage first starts on its independent course (which really means that some individuals of a pre-existing stock enter a new field), then I see no reason to predict that it will necessarily pass through periods of youth, maturity, and old age, that it will increase to an acme of numbers, of variety, or of specialisation, and then decline through a second childhood to ultimate extinction. Still less can we say that, as the individuals of a species have their allotted span of time, long or short, so the species or the lineage has its predestined term. The exceptions to those assertions are indeed recognised by the supporters of such views, and they are explained in terms of rejuvenescence, rhythmic cycles, or a grand despairing outburst before death. This phraseology is delightful as metaphor, and the conceptions have had their value in promoting search for confirmatory or contradictory evidence. But do they lead to any broad and fructifying principle? When one analyses them.one is per- petually brought up against some transcendental assumption, some 86 SECTIONAL ADDRESSES. unknown entelechy that starts and controls the machine, but must for eyer evade the methods of our science. The facts of recurrence, of rhythm, of rise and fall, of marvellous efflorescences, of gradual decline, or of sudden disappearances, all are incontestable. But if we accept the intimate relation of organism and environment, we shall surmise that on a planet with such a geological history as ours, with its recurrence of similar physical changes, the phenomena of life must reflect the great rhythmic waves that have uplifted the mountains and lowered the deeps, no less than every smaller wave and ripple that has from age to age diversified and enlivened the face of our restless mother. To correlate the succession of living forms with all these changes is the task of the palaeontologist. To attempt it he will need the aid of every kind of biologist, every kind of geologist. But this attempt is not in its nature impossible, and each advance to the ultimate goal will, in the future as in the past, provide both geologist and biologist with new light on their particular problems. | When the correlation shall have been completed, our geological systems and epochs will no longer be defined by gaps in our knowledge, but will be the true expression of the actual rhythm of evolution. Lyell’s great postulate of the uni- form action of nature is still our guide; but we have ceased to confound uniformity with monotony. We return, though with a difference, to the conceptions of Cuvier, to those numerous and _ relatively sudden revolutions of the surface of the globe which have produced the corre- sponding dynasties in its succession of inhabitants. The Future. The work of a systematic palaeontologist, especially of one dealing with rare and obscure fossils, often seems remote from the thought and practice of modern science. I have tried to show that it is not really so. But still it may appear to some to have no contact with the urgent problems of the world outside. That also is an error. Whether the views I have criticised or those I have supported are the correct ones is a matter of practical importance. If we are to accept the principle of predetermination, or of blind growth-force, we must accept also a check on our efforts to improve breeds, including those of man, by any other means than crossings and elimination of unfit strains. In spite of all that we may do in this way, there remain those decadent races, whether of ostriches or human beings, which ‘ await alike the inevit- able hour.’ If, on the other hand, we adopt the view that the life- history of races is a response to their environment, then it follows, no doubt, that the past history of liying creatures will have been deter- mined by conditions outside their control, it follows that the idea of human progress as a biological law ceases to be tenable; but, since man has the power of altering his environment and of adapting racial characters through conscious selection, it also follows that progress will not of necessity be followed by decadence; rather that, by aiming at a high mark, by deepening our knowledge of ourselyes and of our world, and by controlling our energy and guiding our efforts in the light of that knowledge, we may prolong and hasten our ascent to ages and to heights as yet beyond prophetic vision. SECTION D: CARDIFF, 1920. ADDRESS LOOLOGICAL SECTION BY Professor J. STANLEY GARDINER, M.A., F.RB.S., PRESIDENT OF THE SECTION, Where do we stand? Tue public has the right to consider and pass judgment on all that affects its civilisation and advancement, and both of these largely depend on the position and advance of science. I ask its consideration of the science of Zoology, whether or not it justifies its existence as such, and, if it does, what are its needs? It is at the parting of the ways. It either has to justify itself as a science or be altogether starved out by the new-found enthusiasm for chemistry and physics, due to the belief in their immediate application to industries. It is a truism to point out that the recent developments in chemistry and physics depend, in the main, on the researches of men whose names are scarcely known to the public: this is equally true for all sciences. A list of past Presidents of the Royal Society conveys nothing to the public compared with a list of Captains of Industry who, to do them justice, are the first to recognise that they owe their position and wealth to these scientists. These men of science are unknown to the public, not on account of the smallness of their discoveries, but rather on account of their magnitude, which makes them meaningless to the mass. Great as have been the results in physical sciences applied to industry, the study of animal life can claim discoveries just as great. Their greatest value, however, lies not in the production of wealth, but rather in their broad applicability to human life. Man ig an animal and he is subject to the same laws as other animals. He learns by the experience of his forebears, but he learns, also, by the consideration of other animals in relationship to their fellows and to the world at large: The whole idea of evolution, for instance, is of indescribable value; it permeates all life to-day ; and yet Charles Darwin, whose researches did more than any others to establish its facts, is too often only known to the public as ‘the man who said we came from monkeys.’ 88 SECTIONAL ADDRESSES. Whilst first and foremost I would base my claim for the study of animal life on this consideration, we cannot neglect the help it has given to the physical welfare of man’s body. It is not out of place to draw attention to the manner in which pure zoological science has worked hand in hand with the science of medicine. Harvey’s experimental discovery of the circulation of the ‘blood laid the foundation for that real knowledge of the working of the human body which is at the basis of medicine; our experience of the history of its development gives us good grounds to hope that the work that is now being carried out by numerous researchers under the term ‘ experimental’ will ultimately elevate the art of diagnosis into an exact science. Harvey’s work, too, mostly on developing chicks, was the starting-point for our knowledge of human development and growth. Instances in medicine could be multiplied wherein clinical treatment has only been rendered possible by laborious research into the life histories of certain parasites preying often on man and other animals alternately. In this connection there seems reason at present for the belief that the great problem of medical science, cancer, will reach its solution from the zoological side. A pure zoologist has shown that typical cancer of the stomach of the rat can be produced by a parasitic threadworm (allied to that found in pork, Trichina), this having as a carrying host the American cock- roach, brought over to the large warehouses of Copenhagen in sacks of sugar. Our attack on such parasites is only made effective by what we know of them in lower forms, which we can deal with at will. Millions of the best of our race owe their lives to the labours of forgotten men of science, who laid the foundations of our knowledge of the generations of insects and flat-worms, the modes of life of lice and ticks, and the physiology of such lowly creatures as Ameba and Paramecium; parasitic disease—malaria, Bilharziasis, typhus, trench fever and dysentery— was as deadly a foe to us as was the Hun. Of immense economic importance in the whole domain of domestic animals and plants was the rediscovery, early in the present century, of the complefely forgotten work of Gregor Mendel on cross-breeding, made known to the present generation largely by the labours of a former President of this Association, who, true man of science, claims no credit for himself. We see results already in the few years that lave elapsed in special breeds of wheat, in which have been combined with exactitude the qualities man desires. The results are in the making—and this is true of all things in biology—but can anyone doubt that the breeding of animals is becoming an exact science? We have got far, perhaps, but we want to get much further in our understand- ing of the laws governing human heredity; we have to establish immunity to disease. Without the purely scientific study of chromo- somes (the bodies which carry the physical and mental characteristics of parents to children) we could have got nowhere, and to reach our goal we must know more of the various forces which in combination make up what we term life. In agricultural sciences we are confronted with pests in half a dozen different groups of animals. We have often to discover which of two or more is the damaging form, and the difficulty is greater D.—-ZOOLOGY. 89 where the damage is due to association between plant and animal pests. Insects are, perhaps, the worst offenders, and our basal knowledge of them as living organisms—they can do no damage when dead, and perhaps pinned in our showcases—is due to Redi, Schwammerdam, and Réaumur in the middle of the seventeenth century. Our present successful honey production is founded on the curiosity of these men in respect to the origin of life and the generations of insects. The fact that most of the dominant insects have a worm (caterpillar or maggot) stage of growth, often of far longer duration than that of the inseets, has made systematic descriptive work on the relation of worm and insect of peculiar importance. I hesitate, however, to refer to catalogues in which perhaps a million different forms of adults and young are described. Nowadays we know, to a large degree, with what pests we deal and we are seeking remedies. We fumigate and we spray, spending millions of money, but the next remedy is in the use of free-living enemies or parasites to prey on the insect pests. The close correlation of anatomy with function is of use here in that life histories, whether parasitic, carnivorous, vegetarian, or saprophagous, can be foretold in fly maggots from the structure of the front part of their gut (pharynx) ; we know whether any maggot is a pest, is harmless, or is beneficial. I won’t disappoint those who expect me to refer more deeply to science in respect to fisheries, but its operations in this field are less known to the public at large. The opening up of our north-western grounds and banks is due to the scientific curiosity of Wyville Thomson and his confréres as to the existence or non-existence of animal life in the deep sea. It was sheer desire for knowledge that attracted a host of inquirers to investigate the life history of river eels. The wonder of a fish living in our shallowest pools and travelling two or three thousand miles to breed, very likely on the bottom in 2,000 fathoms, and subjected to pressures varying from 14 lb. to 2 tons per square inch, is peculiarly attractive. It shows its results in regular eel farming, the catching and transplantation of the baby eels out of the Severn into suitable waters, which cannot, by the efforts of Nature alone, be sure of their regular supply. Purely scientific observations on the life histories of flat fish—these were largely stimulated by the scientific curiosity induced by the views of Lamarck and Darwin as to the causes underlying their anatomical development—and on the feeding value and nature of Thisted Bredning and the Dogger Bank, led to the successful experiments on transplantation of young plaice to these grounds and the phenomenal growth results obtained, particu- larly on the latter. Who can doubt that this ‘ movement of herds’ is one of the first results to be applied in the farming of the North Sea as soon as the conservation of our fish supply becomes a question of necessity ? The abundance of mackerel is connected with the movements of Atlantic water into the British Channel andthe North Sea, movements depending on complex astronomical, chemical, and physical conditions. ‘They are further related to the food of the mackerel, smaller animal life which dwells only in these Atlantic waters. These depend, as indeed do all animals, on that living matter which possesses chlorophyll 50 SECTIONAL ADDRESSES. for its nutrition and which we call plant. In this case the plants are spores of algae, diatoms, etc., and their abundance as food again depends on the amount of the light of the sun—the ultimate source, it might seem, of all life. A method of ascertaining the age of fishes was sought purely to correlate age with growth in comparison with the growth of air-living vertebrates. This method was found in the rings of growth in the scales, and now the ascertaining of age-groups in herring shoals enables the Norwegian fishermen to know with certainty what possibilities and probabilities are before them in the forthcoming season. From the work on the blending together of Atlantic with Baltic and North Sea water off the Baltic Bight and of the subsequent movements of this Bank water, as it. is termed, into the Swedish fiords can be understood, year by year, the Swedish herring fishery. It is interesting that these fisheries have been further correlated with cycles of sun spots, and also with longer cycles of lunar changes. The mass of seemingly unproductive scientific inquiries undertaken by the United States Bureau of Fisheries, thirty to fifty years ago, was the forerunner of their immense fish-hatching operations, whereby billions of fish eggs are stripped year by year and the fresh waters of that country made into an important source for the supply of food. The study of the growth stages of lobsters and crabs has resulted in sane regulations to protect the egg-carrying females, and in some keeping up of the supply in spite of the enormously increased demand. Lastly, the study of free-swimming larval stages in mollusea, stimu- lated immensely by their similarity to larval stages in worms and starfishes, has given rise to the establishment of a successful pearl- shell farm at Dongonab, in the Red Sea, and of numerous fresh-water mussel fisheries in the southern rivers of the United States, to supply small shirt buttons. Fishery inyestigation was not originally directed to a more ambitious end than giving a reasonable answer to a question of the wisdom or unwisdom of compulsorily restricting commercial fishing, but it was soon found that this answer could not be obtained without the aid of pure zoology. The spread of trawling—and particularly the intro- duction of steam trawling during the last century—gave rise to grave tears that the stock of fish in home waters might be very seriously depleted by the use of new methods. We first required to know the life histories of the various trawled fish, and Sars and others told us that the eggs of the vast majority of the European marine food species were pelagic; in other words, that they floated, and thus could not be destroyed, as had been alleged. Trawl fishing might have to be regulated all the same, for there might be an insufficient number of parents to keep up the stock. It was clearly necessary to know the habits, movements, and distribution of the fishes, for all were not, throughout their life; or at all seasons. found on the grounds it was practicable to fish. A North Sea plaice of 12 in. in length, a quite moderate size, is usually five years old. The fact that of the female plaice captured in the White Sea, a virgin ground, the vast majority are mature, while less than half the plaice put upon our — D.—ZOOLOGY. 91 markets from certain parts of the southern North Sea in the years immediately before the war had ever spawned, is not only of great interest, but gives rise to grave fears as to the possibility of unrestricted fishing dangerously depleting the stock itself. There is, however, another group of ideas surrounding the question of getting the maximum amount of plaice-meat from the sea; it may be that the best size for catching is in reality below the smallest spawning size. I here merely emphasise that in the plaice we have an instance of an important food fish whose capture it will probably be necessary to regulate, and that in determining how best the stock may be conserved, what sizes should receive partial protection, on what grounds fish congregate and why, and in all the many cognate questions which arise, answers to either can only be given by the aid of zoological science. But why multiply instances of the applications of zoology as a pure science to human affairs? Great results are asked for on every side of human activities. The zoologist, if he be given a chance to live and to hand on his. knowledge and experience to a generation of pupils, can answer many of them. He is increasingly getting done with the collection of anatomical facts, and he is turning more and more to the why and how animals live. We may not know in our generation nor in many generations what life is, but we can know enough to control that life. The consideration of the fact that living matter and water are universally associated opens up high possibilities. The experi- mental reproduction of animals, without the interposition of the male, is immensely interesting; where it will lead no one can foretell. The association of growth with the acidity and alkalinity of the water is a matter of immediate practical importance, especially to fisheries. The probability of dissolved food material in sea and river water, indepen- dent of organised organic life and absorbable over the whole surfaces of animals, is clearly before us. Is it possible that that dissolved material may be even now being created in nature without the assistance of organic life? The knowledge of the existence in food of vitamines, making digestible and usable what in food would otherwise be wasted, may well result in economies of food that will for generations prevent the necessity for the artificial restriction of populations. The parallel between these vitamines and something in sea-water may quite soon apply practically to the consideration of all life in the sea. Finally, what we know of the living matter of germ cells puts before us the not impossible hope that we may influence for the better the generations yet to come. If it is the possibility in the unknown that makes a science, are there not enough possibilities here? Does Zoology, with these prob- lems before it, look like a decayed and worked-out science? Is it not worthy to be ranked with any other science, and is it not worthy of the highest support? Is it likely to show good value for the money spent upon it? Should we not demand for it a Professorial Chair in every University that wishes to be regarded as an educational institution? And has not the occupant of such a Chair a task at least equal in difficulty to that of the occupant of any other Chair? Surely the zoologist may reasonably claim an equal position and pay to that 92 SECTIONAL ADDRESSES. of the devotee of any other science! The researcher is not a huckstet' and will not make this claim on his own behalf, but the occupant of this Chair may be allowed to do so for him. So far I have devoted my attention primarily, in this survey of the position of Zoology, to the usefulness of the subject. Let us now note where we stand in respect to other subjects and in meeting the real need for wide zoological study. All sciences are now being reviewed, and zoology has to meet month by month the increasingly powerful claim of physics and chemistry for public support. Both of these sciences are conspicuously applicable to industry, and this, perhaps, is their best claim. The consideration of life as a science would itself be in danger were it not for the economic applications of physiology to medicine. This is the danger from without, but there is another from within, and this lies in the splitting up of the subject into a series of small sections devoted to special economic ends. They are a real danger in that they are forming enclosures Within a science, while research is more and more breaking down the walls between sciences. Zoology in many Universities scarcely exists, for what is assimilated by agriculturists and medical men are catalogued lists of pests, while medical students merely acquire the technique of observing dead forms of animals other than human— not the intention of the teachers, it is true, but a melancholy fact all the same. The student, I say again, is merely acquiring in ‘ Zoology ’ a travesty of a noble subject, but to this point I return later. Let me now give a few facts which have their sweet and bitter for us who make Zoology our life work. During the war we wanted men who had passed the Honours Schools in Zoology—and hence, were pre- sumably capable of doing the work—to train for the diagnosis of proto- zoal disease. We asked for all names from 1905 to 1914 inclusive, and the average worked out at under fourteen per year from all English Universities: an average of one student per University per year. In the year 1913-14 every student who had done his Honours Course in Zoology in 1913 could, if he had taken entomology as his subject, have been absorbed into the economic applications of that subject. Trained men were wanted to undertake scientific fishery investigations and they could not be found. Posts were advertised in Animal Breeding, in Helminthology, and in Protozoology, three other economic sides of the subject. The Natural History Museum wanted systematists and there were many advertisements for teachers. How many of these posts were filled I don’t know, but it is clear that not more than one- half—or even one-third—can have been filled efficiently. Can any zoologist say that all is well with his subject in the face of these deficiencies? The demands for men in the economic sides of zoology are con- tinually growing, and it is the business of Universities to try and meet these demands. There are Departments of Government at home and in our Colonies, which, in the interests of the people they govern, wish to put into operation protective measures but cannot do so because there are not the men with the requisite knowledge and common sense required for Inspectorates. There are others that wish for research D.—ZOOLOGY. 938 t to develop seas, to conserve existing industries as well as to discover new : . | b . ‘ : ones, and they, too, are compelled to mark time. In default, or in spite of, the efforts of the schools of pure zoology, attempts are being made to set up special training schools in fisheries, in entomology, and in other economic applications of zoology. Hach branch is regarded as a science and the supporters of each suppose they can, from the commencement of a lad’s scientific training, give specialised instruction in each. The researcher in each has to do the research which the economic side requires. But he can’t restrict his education to one science; he requires to know the principles of all sciences; he must attempt to understand what life is. Moreover, his specialist knowledge can seldom be in one science. The economic entomologist, however deep his knowledge of insects may be, will find himself frequently at fault in distinguishing cause and effect unless he has some knowledge of mycology. The protozoologist must have an intimate knowledge of unicellular plants, bacterial and other. The animal-breeder must know the work on cross-fertilisation of plants. The fisheries man requires to understand physical oceanography. The helminthologist and the veterinary surgeon require an intimate know- ledge of a rather specialised ‘ physiology.’ All need knowledge of the comparative physiology of animals in other groups beyond those with which they deal, to assist them in their deductions and to aid them to secure the widest outlook. It is surely a mistake, while the greatest scientific minds of the day find that they require the widest knowledge, to endeavour to get great scientific results out of students whose train- ing has been narrow and specialised. Such specialisation requires to come later, and can replace nothing. ‘This short cut is the longest way round. The danger is not only in our science, but in every science. In face of this highly gratifying need for trained zoologists, indepen- dently of medical schools, I ask my colleagues in the teaching of zoology, ‘What is wrong with our schools of zoology that they are producing so few men of science? It is not the subject! Can it be our presenta- tion of it, or is it merely a question of inadequate stipends? ’ In science schools there can be no standing still. Progress or retrogression in thought, technique, and method are the two alterna- tives. If we are to progress we must see ever wider vistas of thought, and must use the achievements of cur predecessors as the take-off for our own advances. The foundations of our science were well and truly laid, but we must not count the bricks for ever, but add to them. Par be it from me to decry the knowledge and ideas our predecessors _haye given to us. To have proved the possibility, nay, probability, that all life is one life and that life itself is permanent is an immense achieve- ment. To have catalogued the multitudinous forms that life takes in each country was a herculean task. To have studied with meticulous eare the shapes, forms, and developments of organs in so many bodies was equally herculean. It was as much as could be expected in the nineteenth century, during most of which zoology was in advance of all other sciences. But surely for these pioneer workers this docket- ing, tabulating, and collecting was not the object of their research, but the means to its attainment, The prize they sought was the under- 4 SECTIONAL ADDRESSES. standing of life itself, the intangible mystery which makes ourselves akin to all these specimens, the common possession which gives to man, as to the lowest creature, the power of growth and reproduction. To my colleagues I say, let us no longer, in the reconstruction immediately before us, tie ourselves down to the re-chewing of our dry bones. They are but dead bones, and the great mystery which once lived in them has passed from them, and it is that we must now seek. Not in bones, in myriads of named specimens, does that mystery dwell, but in the living being itself, in the growth and reproduction of live creatures. Observation and experiment rather than tabulation and docketing are our technique. What is that life, common to you, to me, to our domestic pets, to animals and to plants alike? Surely this is our goal, and the contents of our museums, means to this end, are in danger of being regarded as the end. There is hope now. Those of us who have the will to look can see zoology in its proper plaéé, the colleague of botany in applying physics and chemistry to the under- standing of life itself. The study of life is the oldest of all sciences; it is the science in which the child earliest takes an interest; its study has all the attributes required for education of the highest type, for the appreciation of the beauty of form and of music, of unselfishness, of self-control, of imagination, of love, and constancy. The more we know of life, the more we appreciate its wonders and the moré we want t know ; it is good to be alive. Surely the time has now come for us to lift our eyes from our tables of groups and families, and, on the foundations of the know- ledge of these, work on the processes going on in the living body, the adaptation to environment, the problems of heredity, and of many another fascinating hunt in unknown country. Let us teach our students not only what is known, but, still more, what is unknown, for in the pursuit of the latter we shall engage eager spirits who care nought for collections of corpses. My own conviction is that we are in danger of burying our live subject along with our specimens in museums. We see the same evil at work in the teaching of zoology from the very beginning. Those of us who are parents know that the problems of life assail a child almost as soon as it can speak, and that it is the animal side of creation which makes the most natural and immediate appeal to its interest and curiosity. Where such interest is intelligent and constant it is safe to educate truly in the desired direction. You will notice that the child’s questions are very fundamental and that, according to my experience, the facts elicited are applied widely, and with perfect simplicity. ‘Thus my own small daughter, having elicited where the baby rabbits came from, said ‘ Oh! just like eggs from hens.’ The child’s own desires show up best what his mind requires for its due development, and I fear no contradiction in claiming that it is animal life in all its living aspects. Yet what is he given? Schools encourage ‘natural history,’ as it is termed. In some it is nature; but too often it consists in a series of prizes for dates—when the first blooms of wild flowers were found; the first nests, eggs, and young of birds ; the records of butterflies and moths, etc. Actual instruction, if there is any beyond this systematic teaching of destruction, frequently D.—ZOOLOGY. 95 _ lies solely in a few sheets of the life histories of the cabbage butterfly 1 , : and other insects. Fossil sea urchins and shells are curiosities and are used to teach names. The whole is taught—there are some striking exceptions—with the minimum requirements of observation and intelli- gence. Plants too often dominate. The lad can pluck flowers and tear up roots; there is a certain cruelty to be discouraged if animals are treated similarly, but here there is none, for ‘they are not alive’ as _weare. Which one of us would agree to this, and say that there is not a similar ‘ cruelty’ in tearing up plants? The method is the ae — negation of science. The boy must be taught from the other end, from fhe ohe animal about which he does know a little, viz., himself. From the commencement he must associate himself with all living matter. The child—boy or girl—shows us the way in that he is invariably keener on the domestic pets, while he has to be bribed by pennies to learn plant names. As a result of the wrong teaching of zoology we see proposals to make so-called “nature study’ in our schools purely, botanical. Is this proposal made in the interests of the teacher or the children? It surely can’t be for ‘ decency ’ if the teaching is honest, for the pheno- mena are the same, and there is nothing ‘indecent’ common to all life. ‘The proper study of mankind is man,’ and the poor child, athirst for information about himself, is given a piece of moss or duck- weed, or even a chaste buttercup. Is the child supposed to get some knowledge it can apply economically? Whatever the underlying ideas may be, this course will not best develop the mind to enable it to grapple with all phenomena, the aim of education. If necessary, the scliool teacher must. go to school; he must bring himself up to date in _ his own time, as every teacher in science has to do; it is the business of Universities to help him, for nothing is more important to all science than the foundations of knowledge. Into schools is now moving the teaching required for the first professional examination in medicine, and this profoundly affects the _ whole attitude of teachers. It has a syllabus approved by the Union of Medicine, the ‘ apprenticeship ’ to which is as real and as difficult to alter as that of any expert trade with its own union. It compels the remembering of a number of anatomical facts relating to a miscellaneous seléction of animals and plants, and the acquirement of a certain amount of technique. However it may be taught, its examination can almost invariably be passed on memory and manual dexterity ; it implies no standard of mental ability. Anatomy without function and know- ledge of an organism without reference to its life is surely futile. And yet, too often, this is what our colleagues concerned with the second year of this apprenticeship directly or indirectly compel us to teach in the first year. Surely it is time for us to rebel and insist that what is required is education as to the real meaning of what life is. We shall never reach complete agreement as to a syllabus, but probably we are all at one in regarding reproduction as the most interesting biological phenomenon, and water and air as the most important environ- ments. Unfortunately most Universities have adopted this in many ways 96 SECTIONAL ADDRESSES. unscientific and rather useless first Medical Examination as part. of their first examination for the B.Sc. degree and for diplomas and degrees in agriculture, dentistry, and other subjects. Zoology is part of a syllabus in which half a dozen professors are concerned, and it cannot change with the times without great difficulty. Our colleagues of other sciences do not want it to change, preferring that a rival subject to attract pupils should remain in a backwash; to be just, each has a firm belief in the subject he knows. For our continuation courses, having choked out the more thinking students, we have to go on as we have begun, and we survey the animal kingdom in a more or less systematic manner. We carefully see that all our beasts are killed before we commence upon them; we deal solely with their compara- tive anatomy, to which are often added some stories of ‘ evolution,’ fhe whole an attempted history of the animal kingdom. There are great educational merits in the study of the comparative anatomy of a group of similar animals, but too often we go to group after group, the student attaining all that is educational in the first, only securing from each subsequent group more and more facts which might just as well be culled from text-books. Students who continue further and take the final honours in zoology specialise in most Universities in their last year in some branch of their science. Such students are usually thinking of the subject from the point of view of their subsequent livelihood. They have to think of what will pay and in what branches there is, in their University, some teacher from whom they can get special instruction. They read up the most modern text-book, examine a few specimens, and are often given the class they desire by examiners who know less of their speciality than they do. They are then supposed to be qualified both to teach and research in zoology. They teach on the same vicious lines, and in research many are satisfied to become mere accumulators of more facts in regard to dead creatures. I have called this address ‘ Where do we stand?’ and I hope all who are interested will try to answer this question. Personally I feel that we stand in a most uncomfortable position, in which, to use a colloquialism, we must either get on or get out. I am certain that the progress of humanity requires us to ‘ get on.’ Of you in my audience who are not workers in science I ask a final moment of consideration. There is no knowledge of which it is possible to answer the question, ‘ What is the use of it?’ for only time can disclose what are the full bearings of any piece of know- ledge. Let us not starve pure research because we do not see its immediate application. I often think that if Sir Isaac Newton, at the present day, discovered the law of gravity as a result of watching the apples fall, someone would say, ‘ Oh! interesting, no doubt: but my money will go to the man who can stop the maggots in them.’ On the one side leads the path of economic research, offering more obvious attractions in the way of rapid results and of greater immediate recognition. That path is one trodden by noble steps, full of sacrifice and difficulty, worthy of treading. But let us view with still greater sympathy and understanding the harder path which leads workers, D.— ZOOLOGY. 97 through years of seemingly unproductive toil, to strive after the solution of the great basal problems of life. Such workers forfeit for themselves the hope of wealth, leisure, and public recognition. As a rule they die in harness, and leave not much beyond honoured names. ‘These are they who worship at the Altar of the Unknown, who at great cost wrest from the darkness its secrets, not recking of the boon they may bring to humanity. It is for these I plead, not for themselves as individuals, but for the means wherewith to keep the flame of pure research burning, for the laboratories and equipment that all Universities need. 1920 H SECTION E: CARDIFF, 1920. ADDRESS TO THE GEOGRAPHICAL SECTION BY JOHN McFARLANE, M.A, PRESIDENT OF THE SECTION. SincE the last meeting of the British Association, Treaties of Peace have been signed with Austria, Hungary, Bulgaria, and Turkey; and, although there is still much which is unsettled, especially in the East, it 1s now possible to obtain some idea of the changes wrought on the map of Europe by the Great War. These changes are indeed of the most profound and far-reaching description. Old States have in some cases either disappeared or suffered an enormous loss of territory, and new States, with the very names of which we are but vaguely familiar, have been brought into existence. It has seemed to me, therefore, that it might not be altogether inappropriate to inquire into the prin- ciples upon which these territorial changes have been made, and to consider how far the political units affected by them possess the elements of stability. A learned but pessimistic historian to whom I confided my intention shook his head and gravely remarked, ‘ Whatever you say on that subject will be writ in water.’ But the more I consider the matter the more do I feel convinced that certain features in the reconstructed Europe are of great and even of permanent value, and it is in that belief that I have ventured to disregard the warning which was given me. In the rearrangement of European States which has taken place, geographical conditions have perhaps not always had the consideration which they deserve, but in an inquiry such as that upon which we are engaged they naturally occupy the first place. And by geographical conditions I am not thinking primarily, or even mainly, of defensive frontiers. It may be true, as Sir Thomas Holdich implies, that they alone form the true limits of a State. But if they do we ought to carry our theory to its logical conclusion and crown them with barbed- wire entanglements. Whether mankind would be happier or even safer if placed in a series of gigantic compounds I greatly doubt. It is to the land within the frontier, and not to the frontier itself, that our main consideration should be given. The factors which we have to take into account are those which enable a people to lead a common national E.—GEOGRAPHY. 99 life, to develop the economic resources of the region within which they dwell, to communicate freely with other peoples, and to provide not only for the needs of the moment, but as far as possible for those arising out of the natural increase of the population. The principle of self-determination has likewise played an important, if not always a well-defined, part in the rearrangement of EKurope. The basis upon which the new nationalities have been constituted is on the whole ethnical, though it is true that within the main ethnical divisions advantage has been taken of the further differentiation in racial characteristics arising out of differences in geographical environ- ment, history, language, and religion. But no more striking illustration could be adduced of the strength of ethnic relationships at the present time than the union of the Czechs with the Slovaks, or of the Serbs with the Croats and the Slovenes. Economic considerations, of course, played a great part in the settlement arrived at with Germany, but on the whole less weight has been attached to them than to ethnic condi- tions. In cases where they have been allowed to influence the final decision the result arrived at has not always been a happy one. Nor can more be said for those cases where the motive was political or strategic. Historical claims, which have been urged mainly by Powers anxious to obtain more than that to which they are entitled on other grounds, may be regarded as the weakest of all claims to the possession of new territory. When we come to examine the application of the principles which I have indicated to the settlement of Europe we shall, I think, find that the promise of stability is greatest in those cases where geographical and ethnical conditions are most in harmony, and least where undue weight has been given to conditions which are neither geographical nor ethnical. The restoration of Alsace-Lorraine to France has always been treated as a foregone conclusion in the event of a successful termination of the war against Germany. From the geographical point of view, however, there are certainly objections to the inclusion of Alsace within French territory. The true frontier of France in that region is the Vosges, not necessarily because they form the best defensive frontier, but because Alsace belongs to the Rhineland, and the possession of it brings France into a position from which trouble with Germany may arise in the future. Nor can French claims to Alsace be justified on ethnical grounds. The population of the region contains a strong Teutonic element, as indeed does that of Northern France, and the language spoken by over 90 per cent. of the people is German. On the other hand, it must be borne in mind that during the period between the annexation of Alsace by France in the seventeenth century and its annexation by Germany in the nineteenth French policy appears to have been highly successful in winning over the sympathies of the Alsatians, just as between 1871 and 1914 German policy was no less successful in alienat- ing them. The restoration of Alsace must therefore be defended, if at all, on the ground that its inhabitants are more attached to France than to Germany. That attachment it will be necessary for France to preserve in the future, as economic conditions are not altogether favour- H2 100 SECTIONAL ADDRESSES. able. The cotton industry of Alsace may perhaps attach itself to that of France without great difficulty ; but the agricultural produce of the Rhine plain will as before be likely to find its best and most conyenient market in the industrial regions of Germany. With regard to Lorraine the position is somewhat different. Physi- cally that region belongs in the main to the country of the Paris basin, and is therefore in a sense part of France. Strategically it commands the routes which enter France from Germany between Belgium and the Vosges, and from that point of view its possession is of the utmost importance to her. Of the native population about one-third speak French, and the German element is mainly concentrated in the more densely populated districts of the north-east. But although in these various aspects Lorraine may be regarded as belonging to France in a sense in which Alsace does not, the real argument for the restoration of the ceded provinces is in both cases the same. Lorraine, no. less than Alsace, is French in its civilisation and in its sympathies. From the economic point of view, however, the great deposits of iron ore in Lorraine constitute its chief attraction for France to-day, just as they appear to have constituted its chief attraction for Germany half a century ago. But the transfer of the province from Germany, which has built up a great industry on the exploitation of its mines, to France, which does not possess in sufficient. abundance coal for smelting purposes, together with other arrangements of a territorial or quasi-territorial nature made partly at least in consequence of this transfer, at once raises questions as to the extent to which the economic stability of Germany is threatened. The position of that country, with regard to the manufacture of iron and steel will be greatly affected, for not only does she lose, in Lorraine and the Saar, regions in which these manufactures were highly developed, but she loses in them the sources from which other manufacturing regions still left to her, notably the Ruhr, drew considerable quantities either of raw materials or of semi- manufactured goods. For example, in 1913 the Ruhr, which produced over 40 per cent. of the pig iron of the German Empire, obtained 15 per cent. of its iron ore from Lorraine, and it also obtained from there and from the Saar a large amount of pig iron for the manufacture of steel. Unless, therefore, arrangements can be made for a continued supply of these materials a number of its industrial establishments will have to be closed down. In regard to coal, the position is also serious.. We need not, perhaps, be unduly impressed by the somewhat alarmist attitude of Mr. Keynes, who estimates that on the basis of the 1913 figures Germany, as she is now constituted, will require for the pre-war efficiency of her rail- ways and industries an annual output of 110,000,000 tons, and that instead she will have in future only 100,000,000 tons, of which 40,000,000 will be mortgaged to the Allies. In arriving at these figures Mr. Keynes has made an allowance of 18,000,000 tons for decreased production, one-half of which is caused by the German miner having shortened his shift from eight and a half to. seven hours per day. This is certainly a deduction which we need not take into account. Mr. Keynes also leaves out of his calculation the fact that previous to the B.—-GEOGRAPHY. 101 war about 10,000,000 tons per year were sent from Upper Silesia to other parts of Germany, and there is no reason to suppose that this amount need be greatly reduced, especially in view of Article 90 of the Treaty of Versailles, which provides that ‘for a period of fifteen years Poland will permit the produce of the mines of Upper Silesia to be available for sale to purchasers in Germany on terms as favourable as are applicable to like products sold under similar conditions in Poland or in any other country.’ We have further to take into account the opportunities for economy in the use of coal, the reduction in the amount which will be required for bunkers, the possibility of renewing imports from abroad—to a very limited extent indeed, but still to some extent—and the fact that the French mines are being restored more rapidly than at one time appeared. possible. (On the basis of the production of the first four months of 1920 Germany could already reduce her Treaty obligations to France by 1,000,000 tons per year.) Taking all of these facts into account, it is probably correct to say that when Germany can restore the output of the mines left to her to the 1913 figure, she will, as regards her coal supply for industrial purposes, be in a position not very far removed from that in which she was in 1910, when her total consumption, apart from that at the mines, was about 100,000,000 tons. The actual arrangements which have been made, it is true, are in some cases open to objection. The Saar is not geographically part of France, and its inhabitants are German by race, language, and sym- pathy. It is only in the economic necessities of the situation that a defence, though hardly a justification, of the annexation of the coal- field can be found. The coal from it is to be used in the main for the same purposes as before, whereas if it had been left to Germany much of it might have been diverted to other purposes. In 1913 the total production of Alsace-Lorraine and the Saar amounted to about 18,000,000. tons, while their consumption was about 14,000,000 tons. There is thus apparently a net gain to France of about 4,000,000 tons, but from that must be deducted the amount which the North-Hast of France received from this field in pre-war days. Switzerland also will probably in future continue to draw part of its supplies from the Saar. The stipulation that Germany should for ten years pay part of her indemnities to France, Belgium, and Italy in kind also indicates an attempt to preserve the pre-war distribution of coal in Europe, though in some respects the scales seem to have been rather unfairly weighted against Germany. France, for example, requires a continuance of Westphalian coal for the metallurgical industries of Lorrainé and the Saar, while Germany requires a continuance of Lorraine ore if her iron- works on the Ruhr are not to be closed down. There was therefore nothing unreasonable in the German request that she should be secured her supplies of the latter commodity. Indeed, it would have been to the advantage of both countries if a clause similar to Article 90, which I have already quoted, had been inserted in the Treaty. It is true that temporary arrangements have since been made which will ensure to Germany a considerable proportion of her pre-war consumption of minette ores. But some agreement which enabled the two separate 102 SECTIONAL ADDRESSES. but complementary natural regions of the Saar and the Ruhr to exchange their surplus products on a business basis would have tended to an earlier restoration of good feeling between the two countries. One other question which arises in this connection is the extent to which the steel industry of Germany will suffer by the loss of the regions from which she obtained the semi-manufactured products neces- sary for it. On this subject it is dangerous to prophesy, but when we take into consideration the length of time required for the construction of modern steelworks, the technical skill involved in their management, and the uncertainties with regard to future supplies of fuel, it seems unlikely that France will attempt any rapid development of her steel industry. In that case the Ruhr will still continue to be an important market for Lorraine and the Saar. Our general conclusion, then, is that the territorial arrangements which have been made do not necessarily imperil the economic stability of Germany. The economic consequences of the war are really much more serious than the economic consequences of the peace. Germany has for ten years to make good the difference between the actual and the pre-war production of the French mines which she destroyed. Her own miners are working shorter hours, and as a result her own pro- duction is reduced, and as British miners are doing the same she is unable. to import from this country. For some years these deductions will represent a loss to her of about 40,000,000 tons per annum, and will undoubtedly make her position a serious one. But to give her either the Saar or the Upper Silesian coalfields would be to enable her to pass on to others the debt which she herself has incurred. The re- duction of her annual deliveries of coal to France, Belgium, and Italy was, indeed, the best way in which to show mercy to her. The position of Poland is geographically weak, partly because its surface features are such that the land has no well-marked individuality, and partly because there are on the east and west no natural boundaries to prevent invasion or to restrain the Poles from wandering far beyond the extreme limits of their State. Polish geographers themselves appear to.be conscious of this geographical infirmity, as ‘Vidal de la Blache would have termed it, and in an interesting little work Nalkowski has endeavoured to show that the very transitionality of the land between east and west entitles it to be regarded as a geographical entity. But transitionality is rather the negation of geographical individuality than the basis on which it may be established. And indeed no one has pointed out its dangers more clearly than Nalkowski himself. ‘The Polish people,’ he says, ‘living in this transitional country always were, and still are, a prey to a succession of dangers and struggles. They should be ever alert and courageous, remembering that on such a transitional plain, devoid of strategic frontiers, racial boundaries are marked only by the energy and civilisation of the people. If they are strong they advance those frontiers by pushing forward ; by weakening and giving way they promote their contraction. So the mainland may thrust out arms into the sea, or, being weak, may be breached and even overwhelmed by the ocean floads.’ If we bear in mind the constant temptation to a people which E.—GEOGRAPHY. 108 is strong to advance its political no less than its racial frontiers, and the constant danger to which a weakening people is exposed of finding its political frontier contract even more rapidly than its racial, we shall yealise some of the evils to which a State basing its existence on transitionality is exposed. It is, then, to racial feeling, rather than to geographical environ- ment, that we must look for the basis of the new Polish State, but the intensity with which this feeling is likely to operate varies consider- ably in different parts of the region which it is proposed to include. In the plébiscite area of Upper Silesia there were, according to the census of 1900, which is believed to represent the facts more accurately than that of 1910, seven Poles to three of other nationalities. In Prussian Poland, apart from the western districts which have not been annexed to Poland and the town and district of Bromberg, the Poles number at least 75 per cent. of the total population, and in the ceded and plébiscite areas of East and West Prussia 52 per cent. Russian Poland, which contains rather more than two-thirds of the entire popula- tion of what we may call ethnic Poland, has 9,500,000 Poles and over 3,000,000 Jews, Germans, Lithuanians, and others, while West Galicia is almost solidly Polish. Thus out of a total population of 21,000,000 within the regions mentioned the Poles number 15,500,000, or about 75 per cent. Bearing these facts in mind, it is possible to consider the potentialities of the new State. The population is sufficiently large and the Polish element within it is sufficiently strong to justify its independence on ethnical grounds. Moreover, the alien elements which it contains are united neither by racial ties nor by contiguity of settlement. In Posen, for example, there is in the part annexed to Poland a definitely Polish population with a number of isolated German settlements, while in Russian Poland the Jews are to be found mainly in the towns. Con- sidered as a whole, Poland is at least as pure racially as the United States. When we consider the economic resources of Poland we see that they also make for a strong and united State. It is true that in the past the country has failed to develop as an economic unit, but this is a natural result of the partitions and of the different economic systems which have prevailed in different regions. HEyen now, however, we can trace the growth of two belts of industrial activity which will eventually unite these different regions together. One is situated on the coalfield running from Oppeln in Silesia by Cracow and Lemberg, and is engaged in mining, agriculture, and forestry; while the other extends from Posen by Lodz to Warsaw, and has much agricultural wealth and an important textile industry. Moreover, the conditions, geographical and economic, are favourable to the growth of international trade. If Poland obtains Upper Silesia she will have more coal than she requires, and the Upper Silesian fields will, as in the past, export their surplus produce to the surrounding countries, while the manufacturing districts will continue to find their best markets in the Russian area to the east. The outlets of the State are good, for not only has it for all practical purposes 104 SECTIONAL ADDRESSES. control of the port of Danzig, but it is able to share in the navigation of the Oder and it has easy access to the south by way of the Moravian Gap. It seems obvious, therefore, that Poland can best seek compensation for the weakness of her geographical position by developing the natural resources which lie within her ethnic frontiers. By such a policy the different parts of the country will be more closely bound to one another than it is possible to bind them on a basis of racial affinity and national sentiment alone. Moreover, Poland is essentially the land of the Vistula, and whatever is done to improve navigation on that river will similarly tend to have a unifying effect upon the country as a whole. The mention of the Vistula, however, raises one point where geo- graphical and ethnical conditions stand in marked antagonism to one another. The Poles have naturally tried to move downstream to the mouth of the river which gives their country what little geographical individuality it possesses, and the Polish corridor is the expression of that movement. On the other hand, the peoples of Hast and West Prussia are one and the same. The geographical reasons for giving Poland access to the sea are no doubt stronger than the historical reasons for leaving Hast Prussia united to the remainder of Germany, but strategically the position of the corridor is as bad as it can be, and the solution arrived at may not be accepted as final. Lastly, we may consider the case of Hast Galicia, which the Poles claim not on geographical grounds, because it is in reality part of the Ukraine, and not on ethnical grounds, because the great majority of the inhabitants are Little Russians, but on the ground that they are and have for long been the ruling race in the land. It may also be that they are not uninfluenced by the fact that the region contains considerable stores of mineral oil. But as the claim of the Poles to form an independent State is based on the fact that they form a separate race, it is obviously unwise to weaken that claim by annexing a land which counts over 3,000,000 Ruthenes to one-third that number of Poles. Further, the same argument which the Poles use in regard to East Galicia could with no less reason be used by the Germans in Upper Silesia. Mr. Keynes, indeed, suggests that the Allies should declare that in their judgment economic conditions require the inclusion of the coal districts of Upper Silesia in Germany unless the wishes of the inhabitants are decidedly to the contrary. It is not improbable that Kast Galicia would give a more emphatic vote against Polish rule than Upper Silesia will give for it. If Poland is to ensure her position she must forget the limits of her former empire, turn her back on the Russian plain, with all the temptations which it offers, and resolutely set herself to the development of the basin of the Vistula, where alone she can find the conditions which make for strength and safety. Czecho-Slovakia is in various ways the most interesting country in the reconstructed Kurope. Both geographically and ethnically it is marked by some features of great strength, and by others which are a source of considerable weakness to it. Bohemia by its physical structure and its strategic position seems designed by Nature to be the home of a strong and homogeneous people. Moravia attaches itself E.— GEOGRAPHY. 105 more or less naturally to it, since it belongs in part to the Bohemian massif and is in part a dependency of that massif. Slovakia is Carpathian country, with a strip of the Hungarian plain. Thus, while Bohemia ‘possesses great geographical individuality and Slovakia is at least ‘strategically strong, Czecho-Slovakia as a whole does not possess geo- graphical unity and is in a sense strategically weak, since Moravia, ‘which unites the two upland wings of the State, lies across the great route which leads from the Adriatic to the plains of Northern Europe. The country might easily, therefore, be cut in two as the result of a successtul attack, either from the north or from the south. Later I ‘shall endeavour to indicate certain compensations arising out of this diversity of geographical features, but for the moment at least they do not affect our argument. We have, further, to note that the geographical and ethnical con- ditions are not altogether concordant. In Bohemia there is in the basin of the Eger in the north-west an almost homogeneous belt of German people, and on the north-eastern and south-western border- lands there are also strips of country in which the Germanic element is in a considerable majority. It is no doubt true, as Mr. Wallis has shown, that the Czechs are increasing in number more rapidly than the Germans, but on ethnical grounds alone there are undoubtedly strong reasons for detaching at least the north-western district from the Czecho-Slovak State. We feel justified in arguing, however, that here at least the governing factors are and must be geographical. To partition a country which seems predestined by its geographical features to be united and independent would give rise to an intolerable sense of injustice. I do not regard the matter either from the strategic or from the economic point of view, though both of these are no doubt important. What I have in mind is the influence which the geographical conditions of a country exercise upon the political ideas of its inhabi- tants. It is easy to denounce, as Mr. Toynbee does, ‘ the pernicious doctrine of natural frontiers,’ but they will cease to appeal to the human taind only when mountain and river, highland and plain cease to appeal to the human imagination. With good sense on both sides the difficulties in this particular case are not insurmountable. The Germans of the ‘Eger valley, which is known as German Bohemia, have never looked to Germany for leadership nor regarded it as their home, and their main desire has hitherto been to form a separate province in the Austrian ‘Empire. A liberal measure of autonomy might convert them into et citizens, and if they would but condescend to learn the Czech imguage they might come to play an important part in the government of the country. _ In Slovakia also there are racial differences. Within the mountain area the Slovaks form the great majority of the population, but in the Valleys, and on the plains of the Danube to which the valleys open out, the Magyar element. predominates. Moreover, it is the Magyar element Which is racially the stronger, and before which the Slovaks are radually retiring. Geographical and ethnical conditions therefore unite in fixing the political frontier between Magyar and Slovak at the meeting place of hill and plain. But on the west such a frontier would 106 - SECTIONAL ADDRESSES. have been politically inexpedient because of its length and irregularity, and economically disadvantageous because the river valleys, of which there are about a dozen, would have had no easy means of communi- cation with one another or with the outside world. Hence the frontier was carried south to the Danube, and about 1,000,000 Magyars were included in the total population of 3,500,000. Nor is the prospect of assimilating these Magyars particularly bright. The Germans in Bohemia are cut off from the Fatherland by mountain ranges, and, as we have seen, it does not appear to present any great attraction to them. It is otherwise in Slovakia, where the Magyars of the lowland live in close touch with those of the Alfold, and it may be long ere they forget their connection with them. The danger of transferring terri- tory not on geographical or ethnical, but on economic, grounds could not be more strikingly illustrated. With regard to economic development, the future of the new State would appear to be well assured. Bohemia and Moravia were the most important industrial areas in the old Austrian Empire, and Slovakia, in addition to much good agricultural land, contains considerable stores of coal and iron. But if Czecho-Slovakia is to be knit together into a political and economic unit, its communications will have to be developed. We have already suggested that the geographical diversity of the country offers certain compensations for its lack of unity, but these cannot be taken advantage of until its different regions are more closely knit together than they are at present. The north of Bohemia finds its natural outlet both by rail and water through German ports. The south-east of Bohemia and Moravia look towards Vienna. In Slovakia the railways, with only one important exception, converge upon Budapest. The people appear to be alive to the necessity of remedying this state of affairs, and no fewer than fifteen new railways have been projected, which, when completed, will unite Bohemia and Moravia more closely to one another and Slovakia. Moreover, it is proposed to develop the waterways of the country by constructing a canal from the Danube at Pressburg to the Oder. From this canal another will branch off at Prerau and run to Pardubitz on the Elbe, below which point that river has still to be canalised. If these improvements are carried out the position of Czecho-Slovakia will, for an inland State, be remarkably strong. It will have through communication by water with the Black Sea, the North Sea, and the Baltic, and some of the most important land routes of the Continent already run through it. On the other hand, its access to the Adriatic is handicapped by the — fact that in order to reach that sea its goods will have to pass through the territory of two, if not of three, other States, and however well the doctrine of economic rights of way may sound in theory, there are undoubted drawbacks to it in practice. Even with the best intentions, neighbouring States may fail to afford adequate means of transport, through defective organisation, trade disputes, or various other reasons. It is probable, therefore, that the development of internal communica- tions will in the end be to the advantage of the German ports, and more especially of Hamburg. But the other outlets of the State will certainly tend towards the preservation of its economic independence. E.—GEOGRAPHY. 107 The extent to which Rumania has improved her position as a result of the war is for the present a matter of speculation. On the one hand she has added greatly to the territory which she previously held, and superficially she has rendered it more compact; but on the other she has lost her unity of outlook, and strategically at least weakened her position by the abandonment of the Carpathians as her frontier. Again, whereas before the war she had a fairly homogeneous popula- tion—probably from 90 to 95 per cent. of the 7,250,000 people in the country being of Rumanian stock—she has, by the annexation of Transylvania, added an area of 22,000 square miles of territory, in which the Rumanians number less than one and a half out of a total of two and two-third millions. In that part of the Banat which she has obtained there is also a considerable alien element. It is in this combination of geographical division and ethnic intermixture that we may foresee a danger to Rumanian unity. That part of the State which is ethnically least Rumanian is separated from the remainder of the country by a high mountain range, and in its geographical outlook no less than in the racial sympathies of a great number of its inhabitants is turned towards the west, while pre-war Rumania remains pointed towards the south-east. Economically also there is a diversity of interest, and the historical tie is perhaps the most potent factor in binding the two regions together. It is not impossible, therefore, that two autonomous States may eventually be established, more or less closely united according to circumstances. The position in the Dobruja is also open to criticism. Geographi- cally the region belongs to Bulgaria, and the Danube will always be regarded as their true frontier by the Bulgarian people. Ethnically its composition is very mixed, and whatever it was originally, it certainly was not a Rumanian land. But after the Rumanians had rather un- willingly been compelled to accept it in exchange for Bessarabia, filched from them by the Russians, their numbers increased and their economic development of the region, and more especially of the port of Con- stanza, undoubtedly gave them some claims to the northern part of it. As so often happens, however, when a country receives part of a natural region beyond its former boundaries, Rumania is fertile in excuses for annexing more of the Dobruja. To the southern part, which she received after the Balkan wars, and in the possession of which she has been confirmed by the peace terms with Bulgaria, she has neither ethnically nor economically any manner of right. The southern Dobruja is a fertile area which, before its annexation, formed the natural hinterland of the ports of Varna and Ruschuk. Her occupation A it will inevitably draw Rumania on to further intervention in Bulgarian affairs. The arrangements which have been made with regard to the Banat must be considered in relation to the Magyar position in the Hungarian plain. The eastern country of the Banat, Krasso-Szérény, has a population which is in the main Rumanian, and as it belongs to the Carpathian area it is rightly included with Transylvania in Rumanian territory. In the remainder of the Banat, including Arad, the Rumanians form less than one-third of the total population, which also 108 SECTIONAL ADDRESSES. comprises Magyars, Germans, and Serbs. The Hungarian plain is a great natural region, capable of subdivision no doubt, but still a great natural region, in which the Magyar element is predominant. The natural limit of that plain is the mountain region which surrounds it, and to that limit at least the Magyar political power will constantly press. But Rumania has been permitted to descend from the moun- tains and Jugo-Slavia to cross the great river which forms her natural boundary, and both have obtained a foothold on the plain where it may be only too easy for them to seek occasion for further advances. And it cannot be urged that the principle of self-determination would have been violated by leaving the Western Banat to the Magyars. No plébiscite was taken, and it is impossible to say how the German element would have given what in the circumstances would have been the determining vote. Finally, as it was necessary to place nearly a mil- lion Magyars in Transylvania under Rumanian rule, it might not have been altogether inexpedient to leave some Rumanians on Hungarian soil. For the extension of Jugo-Slavia beyond the Danube two pleas have been advanced, one ethnical and the other strategic. Neither is really valid. It is true that there is a Serbian area to the north of Belgrade, but the total number of Serbs within the part assigned to Jugo-Slavia probably does not much exceed 300,000. ‘The strategic argument that the land which they occupy is necessary for the defence of the capital is equally inconclusive. From the military point of view it does not easily lend itself to defensive operations, and when we consider the political needs of the country we cannot avoid the conclusion that a much better solution might have been found in the removal of the capital to some more central position. ‘The Danube is certainly a better defensive frontier than the somewhat arbitrary line which the Supreme Council has drawn across the Hungarian plain. In fact, it is in the treatment of the Hungarian plain that we feel most disposed to criticise the territorial settlements of the Peace Treaties. Geographical principles have been violated by the dismem- berment of a region in which the Magyars were in a majority, and in which they were steadily improving their position. Hthnical principles have been violated, both in the north, where a distinctly Magyar region has been added to Slovakia, and in the south, where the eastern Banat and Backa have been divided between the Rumanians and the Jugo- Slavs, who together forma minority of the total population. For the transfer of Arad to Rumania and of the Burgenland to Austria more is to be said, but the position as a whole is one of unstable equilibrium, and can only be maintained by support from without. In this part of Europe at least a League of Nations will not have to seek for its troubles. When we turn to Austria we are confronted with the great tragedy in the reconstruction of Europe. Of that country it could once be said ‘Bella gerant alii, tu felix Austria nube,’ but to-day, when dynastic bonds have been loosened, the constituent parts of the great but hetero- geneous empire which she thus built up have each gone its own way. And for that result Austria herself is to blame. She failed to realise that an empire such as hers could only be permanently retained on a E.—GEOGRAPHY,. 109 basis of-common political and economic interest. Instead of adopt- ing such a policy, however, she exploited rather than developed the subject. nationalities, and to-day their economic, no less than their political, independence of her is vital to their existence. Thus it is that the Austrian capital, which occupies a situation unrivalled in Kurope, and. which before the war numbered over 2,000,000 souls, finds herself with her occupation gone. For the moment Vienna is not necessary either to Austria or to the so-called Succession States, and she will not be necessary to them until she again has definite functions to perform. I do not overlook the fact that Vienna is also an industrial city, and that it, as well as various other towns in Lower Austria, are at present unable to obtain either raw materals for their industries or foodstuffs for their inhabitants. But there are already indications that this state of affairs. will shortly be ameliorated by economic treaties with the neighbouring States. . And what I am particularly concerned with is not the temporary but the permanent effects of the change which has taken place... The entire political re-orientation of Austria is necessary if she is to emerge successfully from her present trials, and such a re-orientation must be brought about with due regard to geographical and ethnical conditions, The two courses which are open to her lead in opposite directions. On the one hand she may become a member of a Danubian confederation, on the other she may throw in her lot with the German people. The first would really imply an attempt to restore the economic position which she held before the war, but it is questionable whether it is either. possible or expedient for her to make such an attempt... A Danubian confederation twill inevitably be of slow growth, as it is only under the pressure of economic necessity that it will. be. joined by the various. nationalities of south- eastern Europe. The suggestions made by Mr. Asquith, Mr. Keynes, and others, for a compulsory free-trade union would, if carried into effect, be provocative of the most intense resentment among most, if not all, of the States concerned. But even if a Danubian confedera- tion were established it does not follow that Austria would be able to play a part in it similar to that which she played in the Dual Monarchy, With the construction of new railways and the growth of new com- mercial centres it is probable that much of the trade with the south- east of Europe which formerly passed through Vienna will in future go to the east of that city, Even now Pressburg, or Bratislava, to give it the name, by which it will hence be known, is rapidly developing at the expense alike of Vienna and Budapest. Finally, Austria has,in the past shown little capacity to understand the Slay peoples, and in any ease her position in what would primarily be a Slav confederation would be an invidious one. For these reasons we turn to the suggestion that Austria should enter the German Empire, which, both on geographical and on ethnical grounds, would appear to be her proper place. _ Geo- graphically she is German, because the bulk of the territory left to her belongs either to, the Alpine range or to the Alpine foreland. It is only when we reach the basin of Vienna that we leave the mid-world mountain system and look towards the south-east of Europe across the great Hungarian plain. Ethnically, of course, she is essentially 110 SECTIONAL ADDRESSES. German. Now although my argument hitherto has rather endeavoured to show that the transfer of territory from one State to another on purely economic grounds is seldom to be justified, it is equally indefen- sible to argue that two States which are geographically and ethnically related are not to be allowed to unite their fortunes because it would be to their interest to do so. And that it would be to their interest there seems little doubt. Austria would still be able to derive some of her raw materials and foodstuffs from the Succession States, and she would have, in addition, a great German area in which she would find scope for her commercial and financial activities. Even if Naumann were but playing the part of the Tempter, who said ‘ All these things will I give thee if thou wilt fall down and worship me,’ he undoubtedly told the truth when he said ‘ The whole of Germany is now more open to the Viennese crafts than ever before. The Viennese might make an artistic conquest extending to Hamburg and Danzig.’ But not only would Austria find a market for her industrial products in Germany, she would become the great trading centre between Germany and south-east Europe, and in that way would once more be, but in a newer and better sense than before, the Ostmark of the German people. The absorption of Austria in Germany is opposed by France, mainly because she cannot conceive that her great secular struggle with the people on the other side of the Rhine will ever come to an end, and she fears the addition of 6,500,000 to the population of her ancient enemy. But quite apart from the fact that Germany and Austria cannot permanently be prevented from following a common destiny if they so desire, and apart from the fact that politically it is desirable they should do so with at least the tacit assent of the Allied Powers rather than in face of their avowed hostility, there are reasons for thinking that any danger to which France might be exposed by the additional man-power given to Germany would be more than compen- sated for by the altered political condition in Germany herself. Vienna would form an effective counterpoise to Berlin, and all the more so because she is a great geographical centre, while Berlin is more or less a political creation. The South German people have never loved the latter city, and to-day they love her less than ever. In Vienna they would find not only a kindred civilisation with which they would be in sympathy, but a political leadership to which they would readily give heed. In such a Germany, divided in its allegiance between Berlin and Vienna, Prussian animosity to France would be more or less neutralised. Nor would Germany suffer disproportionately to her gain, since in the intermingling of Northern efficiency with Southern culture she would find a remedy for much of the present discontents. When the time comes, and Austria seeks to ally herself with her kin, we hope that no impassable obstacle will be placed in her way. The long and as yet unsettled controversy on the limits of the Italian Kingdom illustrates very well the difficulties which may arise when geographical and ethnical conditions are subordinated to con- siderations of military strategy, history, and sentiment in the deter- mination of national boundaries. The annexation of the Alto Adige has been generally accepted as inevitable. It is true that E.— GEOGRAPHY. 111 the population is German, but here, as in Bohemia, geographical conditions appear to speak the final word. Strategically also the frontier is good, and will do much to allay Italian anxiety with regard to the future. Hence, although ethnical conditions are to some extent ignored, the settlement which has been made will probably be a lasting one. On the east the natural frontier of Italy obviously runs across the uplands from some point near the eastern extremity of the Carnic Alps to the Adriatic. The pre-war frontier was unsatisfactory for one reason because it assigned to Austria the essentially Italian region of the lower Isonzo. But once the lowlands are left on the west the uplands which border them on fhe east, whether Alpine or Karst, mark the natural limits of the Italian Kingdom, and beyond a position on them for strategic reasons the Italians have no claims in this direc- tion except what they can establish on ethnical grounds. To these, therefore, we turn. In Carniola the Slovenes are in a large majority, and in Gorizia they also form the bulk of the population. On the other hand, in the town and district of Trieste the Italians predominate, and they also form a solid block on the west coast of Istria, though the rest of that country is peopled mainly by Slovenes. It seems to follow, therefore, that the plains of the Isonzo, the district of Trieste, and the west coast of Istria, with as much of the neighbouring upland as is necessary to secure their safety and communications, should be Italian and that the remainder should pass to the Jugo-Slavs. The so-called Wilson line, which runs from the neighbourhood of Tarvis fo the mouth of the Arsa, met these requirements fairly well, though it placed from 300,000 to 400,000 Jugo-Slavs under Italian rule, to less than 50,000 Italians, half of whom are in Fiume itself transferred to the Jugo-Slavs. Any additional territory must, by incorporating a larger alien element, be a source of weakness and not of strength to Italy. To Fiume the Italians have no claim beyond the fact that in the town itself they slightly outnumber the Croats, though in the double town of Fiume- ‘Sushak there is a large Slav majority. Beyond the sentimental reasons which they urge in public, however, there is the economic argument, which, perhaps wisely, they keep in the background. So long as Trieste and Fiume belonged to the same empire the limits within which each operated were fairly well defined, but if Fiume become Jugo-Slav it will not only prove a serious rival to Trieste, but will prevent Italy from exercising absolute control over much of the trade of Central Europe. For Trieste itself Italy has in truth little need, and the present condition of that city is eloquent testimony of the extent to which it depended for its prosperity upon the Austrian and German Empires. In the interests, then, not only of Jugo-Slavia buf of Europe generally, Fiume must not become Italian, and the idea of constituting it a Free State might well be abandoned. Its development is more fully assured as the one great port of Jugo-Slavia than under any other form of government. With regard to Italian claims in the Adriatic, little need be said. fp the Dalmatian coast Italy has no right either on geographical or on | \ 112 SECTIONAL ADDRESSES. ethnical grounds, and the possession of Pola, Valona, and some of the islands gives her all the strategic advantages which she has reason to demand. But, after all, the only danger which could threaten her in the Adriatic would come from Jugo-Slavia, and her best insurance against that danger would be an agreement by which the Adriatic should be neutralised. The destruction of the Austro-Hungarian fleet offers ltaly a great opportunity of which she would do well to take advantage. Of the prospects of Jugo-Slavia it is hard to speak with any feeling of certainty. | With the exception of parts of Croatia-Slavonia and of Southern Hungary, the country is from the physical point of view essentially Balkan, and diversity rather than unity is its most pro- nounced characteristic. From this physical diversity there naturally results a diversity in outlook which might indeed be all to the good if the different parts of the country were linked together by a well- developed system of communication. Owing to the structure of the land, however, such a system will take long to complete. Ethnic affinity forms the real basis of union, but whether that union implies unity is another matter. It is arguable that repulsion from the various peoples—Magyars, Turks, and Austrians—by whom they have been oppressed, rather than the attraction of kinship, is the foree which has brought the Jugo-Slavs together. In any case the | obstacles in the way of the growth of a strong national feeling are many. Serb, Croat, and Slovene, though they are all members of the Slav — family, have each their distinctions and characteristics which political differences may tend to exaggerate rather than obliterate. In Serbian : Macedonia, again, out of a total population of 1,100,000, there are 400,000 to 500,000 people who, though Slavs, are Bulgarian in their sympathies, and between Serb and Bulgarian there will long be bitter enmity. Religious differences are not wanting. The Serbs belong to the Orthodox Church, but the Croats are Catholics, and in Bosnia there is a strong Mohammedan element. Cultural conditions show a wide range. The Macedonian Serb, who has but lately escaped from Turkish misrule, the untutored but independent Montenegrin, the Dal-— matian, with his long traditions of Italian civilisation, the Serb of the kingdom, a sturdy fighter but without great political insight, and the Croat and Slovene, whose intellectual superiority is generally admitted, © all stand on different levels in the scale of civilisation. To build up out — of elements in many respects so diverse a common nationality without destroying what is best in each will be a long and laborious task. — Heonomic conditions are not likely to be of much assistance. It is true that they are fairly uniform throughout Jugo-Slavia, and it is improbable that the economic interests of different regions will conflict to any great extent. On the other hand, since each region is more or less self- supporting, they will naturally unite into an economic whole less easily than if there had been greater diversity. What the future holds for Jugo-Slavia it is as yet impossible to say; but the country is one of great potentialities, and a long period of political rest might render possible the development of an important State. This brings me to my conclusion. I have endeavoured to consider the great changes which have been made in Europe not in regard to E.—GEOGRAPHY. 118 the extent to which they do or do not comply with the canons of boundary-making, for after all there are no frontiers in Europe which can in these days of modern warfare be considered as providing a sure defence, but in regard rather to the stability of the States concerned. A great experiment has been made in the new settlement of Europe, and an experiment which contains at least the germs of success. But in many ways it falls far short of perfection, and even if it were perfect it could not be permanent.. The methods which ought to be adopted to render it more equable and to adapt it to changing needs it is not for us to discuss here. But as geographers engaged in the study of the ever-changing relations of man to his environment we can play an important part in the formation of that enlightened public opinion upon which alone a society of nations can be established, 1920 J SECTION F: CARDIFF, 1920. ADDRESS TO THE SECTION OF ECONOMIC SCIENCE AND STATISTICS BY J. H. CLAPHAM, C.B.E., Litt.D., PRESIDENT OF THE SECTION. Ir is, I think, a President’s first duty to record the losses which economic science has sustained since the Association last met. A year ago we had just lost, on the academic side, Archdeacon Cunningham, and on the side of affairs, Sir Edward Holden. This year, happily, I have no such losses to record in either field. But it is right to name the death of a late enemy, Professor Gustav Cohn, of Gdttingen, an economist of the first rank, who had made a special study of English affairs. I believe that no student of our railway history would fail to place Cohn’s ‘ Inquiries into English Railway Policy,’ published (in German) so long ago as 1873, first on the unfortunately very short list of scientific works devoted to that side of history. Kven when supple- mented by an additional volume, issued ten years later, it covers only what seems to-day the prehistoric period of our policy—before the Act of 1888 and very long before our present uncertainties—but it is not yet out of date. Cohn died full of years. He was nearly eighty. I may mention, perhaps, with his name that of a much younger, and possibly more brilliant, German economist, Max Weber, of Munich, who has died at the age of fifty-six. He once tried to explain, by a study of Puritan theology, the economic qualities of the Nonconformist business man—a very fascinating study. But his work as a whole has not roused much interest in England. By an accident the three scholars whose names I have mentioned were all best known, in England at any rate, as historians. And, with your indulgence, I will do what I think has seldom been done from this chair, in making my address largely historical. History has been my main business in life; and it has occurred to me that some com- parisons between the economic condition of Europe after the great wars of a century ago and its condition to-day may not be without interest. Historical situations are never reproduced, even approxi- mately; but it is at least interesting to recall the post-war problems which our grandfathers or great-grandfathers had to face, and how they handled them; to ask how far our sufferings and anxieties have had their parallels in the not remote past; and to note some danger F.—ECONOMICS. 115 signals. By ‘we’ I mean not the British only, but all the peoples of Western and Central Europe. Of Eastern Europe I will only speak incidentally ; for I am unable as yet to extract truth from the conflicting and biassed evidence as to its economic condition. Moreover, there is still war in the Kast. In 1815 France had been engaged in almost continuous wars for twenty-three, England for twenty-two, years. The German States had been at war less continuously; but they had been fought over, conquered, and occupied by the French. Prussia, for instance, was overthrown in 1806. When the final struggle against Napoleon began, in 1812, there was a French army of occupation of nearly 150,000 men in Prussia alone. From 1806 to 1814 Napoleon’s attempt to exclude English trade from the Continent had led to the English blockade— with its striking resemblances to, and its striking differences from, the blockade of 1914-19. Warfare was less horribly intense, and so less economically destructive, than it has become in our day; but what it lacked in intensity it made up in duration. Take, for instance, the loss of life. For England it was relatively small—because for us the wars were never people’s wars. In France also it was relatively small in the earlier years, when armies of the old size were mainly employed. But under Napoleon it became enor- mous. Exact figures do not exist, but French statisticians are disposed to place the losses in the ten years that ended with Waterloo at fully 1,500,000. Some place them higher. As the population of France grew about 40 per cent. between 1805-15 and 1904-14, this would correspond to a loss of, say, 2,100,000 on the population of 1914. The actual losses in 1914-18 are put at 1,370,000 killed and missing; and I believe these figures contain some colonial troops. Or take the debts accumulated by victors and the requisitions or indemnities extorted from the vanquished. The wars of a century ago left the British debt at 848,000,000/. According to our success or failure in securing repayment of loans made to Dominions and Allies, the Great War will have left us with a liability of from eight to nine times that amount. Whether our debt-carrying capacity is eight or nine times what it was a century ago may be doubted, and cannot be accurately determined. But it is not, I would venture to say, less than Six or seven times what it was, and it might well be more. A good deal depends on future price levels. At least the burdens are com- parable ; and we understand better now where to look for broad shoulders to bear them. After Waterloo France was called upon to pay a war indemnity of only 28,000,0001., to be divided among all the victors. With this figure Prussia was thoroughly dissatisfied. Not, I think, without some reason. She reckoned that Napoleon had squeezed out of her alone, between 1806 and 1812, more than twice as much—a tremendous exac- tion, for she was in those days a very poor land of squires and peasants, whose treasury received only a few millions a year. England, who was mainly responsible—and that for sound political reasons—for the low figure demanded of France, found herself, the victor, in the curious position of being far more heavily burdened with debt than France, who T2 116 SECTIONAL ADDRESSES. had lost. England, of course, had acquired much colonial territory ; but on the purely financial side the comparison between her and France was most unequal. England’s total national debt in 1817 was 848,000,0001. France’s debt did not reach 200,000,0001. until 1830. The reasons why France came out. of the wars so well financially were four. First, she had gone bankrupt during the Revolution, and had wiped out most of her old debt. Second, under Napoleon she had made war pay for itself, as the case of Prussia shows. Third, there was No financial operation known to the world in 1815 by which England’s war debt, or even half of it, could have been transferred to France. Fourth, England never suggested any such transference, or, so far as I know, ever even discussed it. France’s financial comfort, immediately after her defeat, extended to her currency. During the Revolution she had made a classical experi- ment in the mismanagement of credit documents, with the assignats issued on the security of confiscated Church property ; but after that she had put her currency in good order. Her final defeat in 1812-14, and again in 1815, did not seriously derange it. Indeed, the English currency was in worse order than the French, owing to the suspension of cash payments by the Bank of England; and so rapidly did France’s credit recover after 1815 that in 1818 French 5 per cents stood at almost exactly the present-day price of British 5 per cent War Loan. That year she finished the payment of her war indemnity, and the last armies of oceupation withdrew. She had no doubt gained by waging war, and eventually suffering defeat, on foreign soil. No French city had been burnt like Moscow, stormed like Badajoz, or made the heart of a gigantic battle ike Leipzig. Napoleon fought one brilliant defensive campaign on French soil, in the valleys of the Marne and the Seine, in 1814. In 1815 his fate was decided in Belgium. Hardly a shot was fired in France; hardly a French cornfield was trampled down. But France, as in 1918, was terribly short of men, and, again as in 1918, her means of communication had suffered. Napoleon’s magnificent roads—he was among the greatest of road engineers—had gone out of repair; his great canal works had been suspended. ‘These things, however, were soon set right by the Government which followed him. France’s rapid recovery brings us to one of the essential differences between Western Europe a century ago and Western Europe to-day. In spite of Paris and her other great towns, the France of 1815 was a rural country, a land of peasants and small farmers. Only about 10 per cent, of her population lived in towns of 10,000 inhabitants or more. The town below 10,000, in all countries, is more often a rural market town, ultimately dependent on the prosperity of agriculture, than an industrial centre. Parallels for France’s condition must be sought to-day in Eastern Europe—in Serbia or Russia. It is a condition which makes the economics of demobilisation easy. The young peasant goes back from the armies to relieve his father, his mother, and his sisters, who have kept the farm going. Moreover, France maintained a stand- ing army of 240,000 men after 1815; and her losses in the Waterloo campaign had been so heavy that the actual numbers demobilised were F.—ECONOMICS. 117 relatively small. Demobilisation left hardly a ripple on the surface of her economic life. The German States were far more rural in character even than France. There were a few industrial districts, of a sort, in the West and in Saxony; a few trading towns of some size, like Hamburg and Frankfurt ; but there was nowhere a city comparable to Paris. In 1819 the twenty-five cities which were to become in our day the greatest of the modern German Empire had not 1,250,000 inhabitants between them. Paris alone at that time had about 700,000. German statesmen, when peace came, were occupied not with problems arising from the situation of the urban wage-earner, though such problems existed, but with how to emancipate the peasants from the condition of semi-servility in which they had lived during the previous century. Here, too, demo- bilisation presented few of the problems familiar to us. Probably not one man in ten demobilised was a pure wage-earner. The rest had links with the soil. The land, neglected during the war, was crying out for labour, and every man had his place, even if it was a servile place, in rural society. Things were different in England; but our demobilisation problem was smaller than that of our Continental allies or enemies, who had mobilised national armies, though not of the modern size. On the other hand, we had kept an immense fleet in commission, the crews of which were rapidly discharged. arly in 1817 Lord Castlereagh stated in Parliament that 300,000 soldiers and sailors had been discharged since the peace. In proportion to population, that would be equivalent, for the whole United Kingdom, to nearly 750,000 to-day. For these men no provision whatever was made. They were simply thrown on the labour market; and the vast majority of them were ex-wage-earners or potential wage-earners, industrial, mercantile, or agricultural. The United Kingdom was not urbanised as it is to-day; but the census of 1821 showed that 21 per cent. of the population lived in cities of 20,000 inhabitants and upwards, and probably about 27 per cent. (as compared with France’s 10 per cent.) lived in places of 10,000 and upwards. As industry in various forms, especially coal-mining, spinning, and weaving, was extensively carried on in rural or semi-rural districts, it is certain that at least one demobilised man of working age in every three was a potential wage-earner of industry or commerce. And as Great Britain had lost most of her peasant-holders, whether owners or small working farmers, the remainder of the demobilised rank and file were nearly all of the agricultural labourer class. They had to find employment ; there was not a place in rural society waiting for them, as there was for the average French or German peasant soldier. It is not surprising that the years from 1815 to 1820 were, both economically and politically, inane the most wretched, difficult, and dangerous in modern English istory. Things were at their worst in 1816-17, both for England and for her Continental neighbours. Western Europe was very near starvation. Had the harvest of 1815 not been excellent, so providing a carry-over of corn, or had the harvest of 1817 been much below the average, there must have been widespread disaster; so thorough and universal 118 SECTIONAL ADDRESSES. was the harvest failure of 1816. In the latter part of 1816 (Decem- ber) wheat fell in England to 55s. 7d., although no grain imports were allowed, except of oats. LHarly in 1816 the United Kingdom was actually exporting a little wheat. Then came a terrible spring—a long frost; snow lying about Edinburgh in May; all the rivers of Western Europe in flood. An equally disastrous summer followed. There was dearth, in places amounting to real famine, everywhere—worst of all in Germany. Unlike France, the German States of a century ago were extraordinarily ill-provided with roads. What roads there were had gone to pieces in the wars. In winter even the mails could hardly get through with sixteen and twenty horses. Food supplies could not be moved over long distances by land; and the slightly more favoured regions could not help the most unfortunate. There was a far wider gap between prices in Kastern and Western Germany in 1816 than there had been in the last bad famine year (1772). Hach German State, in its. anxiety, began to forbid export early in 1816, thus making things worse. At Frankfurt, the representatives of the German States, gathered for the Diet, could hardly feed their horses. Prices rose amazingly and quite irregularly, with the varying food conditions of the various provinces. In the spring of 1817 pallid, half-starved people were wandering the fields, hunting for and grubbing up overlooked and rotten potatoes of the last year’s crop. In England the harvest failure of 1816 drove wheat up to 103s. 7d. a quarter for December of that year, and to 112s. 8d. for June of 1817. In Paris the June price in 1817 was equivalent to 122s. dd. At Stuttgart the May price was equivalent to 138s. 7d. These are only samples. Think what these figures mean at a time when an English agricultural labourer’s wage was about 9s. 6d., and a French or German unskilled wage far less. It must be recalled that there were no special currency causes of high prices either in France or Germany. ‘These were real dearth prices. In the spring of 1817 the French Government was buying corn wherever it could find it—in England, North Africa, America—as another bad harvest was feared. Happily, the 1817 harvest was abundant, here and on the Continent. By September the Mark Lane price of wheat was 77s. 7d., and the Paris price 71s. Od. I have gone into price details for the purpose of drawing a contrast between a century ago and to-day. Except for the damage done to the German roads, the wars had very little to do with these food troubles of 1816-17. High and fluctuating food prices were the natural consequence of the general economic position of Western Europe a century ago. It was only in the most comfortable age in all history— the late nineteenth and early twentieth centuries—that low and stable food prices came to be regarded as normal. In the eighteenth century, when England fed herself and often had an exportable surplus, fluctua- tions were incessant. Take the ten years 1750-1760. The mean price of wheat at Eton in 1752 was 45 per cent. above the mean price in 1750. The mean price in 1757 was nearly 100 per cent. above the mean price of 1750. On Lady Day 1757 the price was 60s. 5jd. On Lady Day 1759 it was 37s. 4d. On Lady Day 1761 it was 26s. 8d. The 1761 mean price was exactly half the 1757 mean price. F.—ECONOMICS. 119 Highteenth-century England was too well organised economically to be in much risk of actual famine, but for Ireland and large parts of the Continent famine was a normal risk, War and its effects had only accentuated, not created, that risk. Imports might reduce it, but could not avert it, because Western Europe tends to have approximately the same harvest conditions throughout, and it was impossible to draw really large supplementary supplies from anywhere else. So unim- portant were overseas supplies that the Continent suffered very much more from the harvest failure of 1816, in time of peace, than from the eight years’ English blockade in time of war. If overseas supplies could be got they were hard to distribute, owing to defective transport facilities. Thanks to the work of the nineteenth century, the most terrific of all wars was required to bring Western Europe face to face with what had been both a war-time and a peace-time risk a century earlier, But the old Europe, if it had the defects, had also the elasticity of a rather primitive economic organism. Given a couple of good harvests, and a land of peasants soon recovers from war. Serbia had a good harvest last year (1919), and was at once in a state of comparative comfort, in spite of her years of suffering. A second good harvest this year, for which fortunately the prospects are favourable, would almost restore her. So it was with France and, to a less extent, Germany in 1816-18. In France acute distress in 1816-17 had been confined to the towns and to those country districts where the harvest failure was worst. The harvest of *17 put an end to it. One gets the impression that in Germany distress among the peasants themselves had been more widespread. Worse communications and the absence of a strong central Government seem to have been the chief causes of this, though perhaps the harvest failure was more complete. In Trance, as we have seen, the central Government took such action as was possible in the interests of the whole country. A parallel might be drawn between the German situation in 1815-17 and that of the States which have arisen from the break-up of the old Austro- Hungarian Empire since 1918. Freed from French domination, and then from the urgent necessity of co-operating against a common enemy, the German States relapsed into their ancient jealousies and conflicting economic policies, just as the new States, which were once subject to the Hapsburgs, have been forbidding exports of food and fuel and disputing with one another. An excellent harvest in 1817 averted the risk of famine in Germany also; but anything that could be called prosperity was long delayed, whereas France was indisputably prosperous, judged by the standards of the day, and far more contented than England, by 1818-20. Germany had been so exhausted by the wars and incessant territorial changes of the Napoleonic age, and was politically so divided, that her economic life remained stagnant and her poverty great until at least 1830. It was all that the various Governments could do to find money for the most essential of all economic measures—the repair and construction of roads—whereas France had her splendid main roads in order again and had resumed work on her canals before 1820. But France had 120 SECTIONAL ADDRESSES. cut her losses nearly twenty years before, and had enjoyed continuous treedom from war on her own territory between 1794 and 1814, as we have seen. She had been well, if autocratically , governed, and her war indemnity was but a trifling burden. Jer peasants were free and, as a class, vigorous and hopeful. She was united and conscious of her leadership in Europe, even through her ultimate defeats. If the experience of Hurope after Waterloo is, on the whole, of good augury for agricultural States, and especially for agricultural States with a competent central Government, for the industrialised modern world that experience is less encouraging. Great Britain alone was partially industrialised in 1815-20, and Great Britain, though victorious, suffered acutely. Mismanagement was largely responsible for her sufferings—mismanagement of, or rather, complete indifference to, problems of demobilisation; mismanagement of taxes (the income tax was abandoned at the clamour of interested parties, and the interest on the huge debt paid mainly from indirect taxes, which bore heavily on the poor); mismanagement of food supplies, by the imposition of the Corn Law; and so on. But suffering due to international economic dis- location followmg war could not have been avoided by management, however good. The situation was unique. England alone of the Kuro- pean Powers had developed her manufactures to some extent on what we call modern lines. During the wars she had accumulated also great stores of colonial and American produce, which could only get into Kurope with difficulty—by way of smuggling. In 1813, before Napo- leon’s first fall, her manufacturers and merchants were eagerly awaiting peace. In 1814 manufactures and colonial produce were rushed over, only to find that, much as Europe desired them, it could not pay the price. It had not enough to give in exchange; and England, being rigidly protectionist. was not always prepared to buy even what Europe had to give. There was no machinery for international buying credits. Merchants shipped at their own risks, usually as a venture, not against a firm order as to-day, and they had to bear their own losses—often up to 50 per cent. Continental economic historians have hardly yet for- given us for this ‘dumping,’ which both drained away the precious metals to Kngland—as there was not much else to pay with—and did a great deal of harm to the struggling young factory industries which had begun to grow up under the protection of Napoleon’s anti-English commercial policy. British exporters were so badly bitten in 1814 that, when peace finally came next year, after Waterloo, they were nervous of giving orders at home—which was very bad for the manufacturing industries and for the men who sought employment in them. There was the curious situation in 1816 that, while the price of wheat was rushing up, most other prices were falling, the bottom of the market being often reached at the end of the year, when the confidence of buyers and shippers began to revive. Raw cotton, for instance, which had touched 2s. 6d. a lb. in 1813-14, fell to a minimum of 1s. 2d. in 1816—although Europe was open and cotton badly needed. It is as yet too early to work out a parallel between this post-war sommercial and industrial slump. and the slump that followed the Great, eee T.—ECONOMICS. 121 War of 1914-18, for we have not yet had it. But it is coming. More certainly, I am inclined to believe, in the United States than in Eng- land; but pretty certainly here also. I say more certainly in the United States because her position bears most resemblance to that of Hngland in 1815-17. Consider that position. What before the war was, on the balance, a debtor country has become a creditor country. That creditor is equipped to export both raw materials and manufactures— iron and steel goods particularly—on a huge scale. It is true she is a heavy importer of some foods, such as sugar, coffee, and tea, and of certain raw materials, such as rubber, timber, and wool. But, owing to her tariff system and her general policy, she is reluctant to take many things which her debtors have to offer. Her recent ‘ dry’ policy, for example, has shut her markets to one of France’s most valuable exports, an export with which France has always been in the habit of paying her creditors. Already, I notice, American business men are beginning to point out what English business men stated clearly in a famous document, the Petition of the London Merchants, a century ago—that the country which will not buy, neither shall it sell. This was the most solid of all free-trade arguments in the early nine- teenth century, and it has lost none of its force. No doubt America is, and will be, glad to take part payment in gold, just as England was in 1814-16. But that is not a permanent solution. If she remains a creditor nation—and there is no present reason to think that she will not—she must in time arrange to take more goods from outside. Her political processes, however, are slow; and it seems unlikely that she will have adjusted her policy before the post-war slump is upon her. The United Kingdom, which, on the whole, still takes freely what its customers have to offer it, is in a better position, provided its customers can go on offering. This may prove an important proviso. Customers who have been litile hurt or even helped by the war—Spain, perhaps, or Egypt, or India, or New Zealand—should continue good buyers. But the uncertainty gives cause for anxious thought in the ease of the war-damaged nations, allied and ex-enemy. Modern financial and commercial organisation has postponed the critical moment in a way that was impossible a century ago. When Europe was hungry in 1816 there were not food surpluses available anywhere on the earth, nor shipping enough on the seas, nor means of transport good enough on land, to relieve her need. If, per impossibile, there had been all these things, there would have been no country or group of business men anywhere ready to give her the necessary credit on a large scale. The Rothschilds, a young firm in those days, did something. They advanced money to a few German princes to buy corn for their people at the Baltic ports, for there was some corn to spare from Poland and Russia. But the huge food-financing operations of 1918-20 would have been as unthinkable as the actual handling of the foodstuffs would ‘have been impossible. Had two harvests like that of 1816 come in succession, there would have been famine and food riots everywhere, past hope of cure. Similarly modern finance is postponing the critical moment for the 122 SEUTIONAL ADDRESSES. international trade in manufactures. _ British business men in 1919-20 have not, I believe, often sent their goods abroad in hope of finding a vent for them, and then been forced to content themselves with prices far below cost of production, as their grandfathers were in 1814-16. Every kind of financial device—long private credit, assistance from banks, credits given by Governments—has been called in, so that trade may be resumed before the war-damaged nations are in a position to pay for what they need by exporting the produce of their own labour. The more industrial the damaged nation is, the more complex is the restarting of her economic activity. Corn grows in nine months, and pigs breed fast. The start once given, countries like Denmark and Serbia, both of which are normally great exporters of pigs or bacon, could soon pay for necessary imports of machinery or fertilisers bought on long credit to restart their rural industries. The United Kingdom, the least damaged of all the combatants except America, is believed by the Chancellor of the Exchequer to be now rather more than paying its way. That may be sanguine, but at the worst our accounts are nearly balanced. What might not have happened in 1919 if modern methods for postponing payment had not been applied internationally ? The other chief combatants are far from paying their way. Italy is importing abnormal quantities of food and also her necessary raw materials with the aid of American and English credits, while Germany, who can get little in the way of credit, has hardly begun even to import the raw materials to make the goods by the export of which she may eventually pay her way, not to mention her indemnities. I have in mind such materials as cotton, wool, rubber, copper, oil-seeds, and hides—all of which she imported heavily in 1913. Some materials, of course, she possesses in abundance, but the working up even of these is hampered by her coal position. I make no political pleas: I merely illustrate the complexity of the restarting of industry under present- day conditions. France has the first claim to assistance in restarting, a claim which we all recognise; but for the comfort and peace of the world a universal restart is desirable. The central problem is one which I can only indicate here, not discuss. Its discussion is for experts with full inside knowledge from month to month, and the answer varies for every country. It is—when will the inability of the war-damaged nations to pay for all that they want, in food and materials, in order to restart full economic activity, make itself felt by the nations who are supplying them, primarily, that is, the United States and ourselves? In 1814-16, when the problem was, of course, infinitely smaller because nations were so much more self-sufficing, the reaction came at once for lack of long organised eredits. Conceivably, all other combatants might do in turn what we seem to have done—that is, adjust their trade balance within a reason- able period and so avoid renewal of special credits. In that case the post-war trade slump would come, not as an international crisis, but as a gradual decline, when the first abnormal demand for goods of all kinds to replenish stocks is over. Already this type of demand is slackening ‘n certain quarters. We shall do very well if we have nothing worse than that gradual decline, which would be eased, in our case, by our ! ,— ECONOMICS, 123 extensive connections with undamaged countries, and by our willingness to buy most things which any nation has to offer. The situation would be still further eased if countries such as Germany and Russia were to develop in turn what might. be called a reconstruction demand, to take the place of the satisfied reconstruction demands of our Allies. But the fear, as I think the quite reasonable fear, expressed in some well- informed quarters, is that, in view of the complicated and dangerous cur- rency position in many countries ; in view of the difficulty which the war- damaged nations have in collecting taxes enough to meet their obliga- tions; in view of the slowness with which some of them are raising production to the level of consumption ; in view of the complete uncer- tainty of the political and economic future in much of Central and Bastern Europe—that in view of these things, and quite apart from pos- sible political disturbances, we shall have to go through a genuine crisis, as distinct from a depression ; a crisis beginning in the field of finance, when some international obligation cannot be met or some international credit cannot be renewed, spreading to industry and giving us a bad spell ef unemployment, comparable with the unemployment of the post-war period a century ago, and more dangerous because of the high standard of living to which the people in this and some other countries is becom- ing accustomed. Personally, I am less apprehensive for the industries of this country than are many whose opinions I should ordinarily be disposed to prefer to my own. A demand, an effective demand, exists for many things that we can supply in great regions outside the war area—in China, for instance, where there is said to be at this moment a keen demand for machinery which the United Kingdom is too much preoccupied with other work to supply. Nor do I fear that a crisis will originate here, as I am disposed to think that our currency and taxation position is already relatively sound. But we should be bound to feel the reactions of acrisis which might occur elsewhere ; to what extent is, however, quite impossible to foresee. One final comparison. An extraordinary feature of the great wars of a century ago was that they coincided with a steady growth of popu- lation, and were followed by a period of rapid growth. For the United Kingdom that fact is well known and not surprising. We lost relatively few men in war. But the official French figures, 97,500,000 in 1801 and 29,500,000 in 1816, are so remarkable that one is tempted to doubt the first enumeration. Though remarkable, the figures are, however, not impossible; and it must be recalled that the losses were spread over many years. British population has grown a little since 1914 ; in spite of separations of man and wife and our three- quarters of a million dead. A main reason has, however, been the suspension of emigration, which was proceeding at a rate of over 200,000 a year just before the war. France estimates a dead loss of over 3,000,000 (on 39,700,000) between 1913 and 1918 on her old territory. Her census is due next year. Comparatively early in the war the German civilian death rate was above the birth rate; so presumably she is in much the same position as France. But, owing to changes of frontier and continued unrest, it is as yet too early to estimate the total 124 SECTIONAL ADDRESSES. effect of the Great War on population. For Western and Central Europe it must, I think, have produced a considerable net loss. For Russia one can hardly guess ; but her population is so largely rural and grew so amazingly fast before 1914, that it would not surprise me very much to learn that, with all her miseries, it had been maintained. The growth of population in Europe after 1815 coincided with the spread of the first industrial and agricultural revolution outwards from the United Kingdom. The world was learning new ways to feed and clothe itself; and it continued to learn all through the century. I myself do not suppose that the age of discovery is at an end, so our troubles may be eased as time goes on; and although I have not the slightest wish that population should ever again grow so fast as it grew in Europe during the nineteenth century, I see no reason why a moderate rate of growth should not be resumed, in a few years at latest. But perhaps I have already committed prophecy, or half prophecy, more than is altogether wise for one in my position. SECTION G; CARDIFF, 1920, ADDRESS TO THE ENGINEERING SECTION BY Proressor C. F. JENKIN, C.B.E., M.A., PRESIDENT OF THE SECTION. Tue importance of research in all branches of industry is now becoming fully recognised. It is hardly necessary to point out the great possi- bilities of the Board of Scientific and Industrial Research, formed just before the war, or to lay stress on the attention which has been called to the need for research by events during the war. Probably in no branch of the Services was more research work done than in the Air Service, and the advances made in all directions in connection with flying were astonishing. My own work was confined to problems connected with materials of construction, and as a result of that work I have come to the conclusion that the time has come when the funda- mental data on which the engineering theories of the strength and suitability of materials are based require thorough overhauling and revision. I believe that the present is a favourable time for this work, but I think that attention needs to be drawn to it, lest research work is all diverted to the problems which attract more attention, owing to their being in the forefront of the advancing engineering knowledge, and lest the necessary drudgery is shirked in favour of the more exciting new discoveries. Tt has been very remarkable how again and again in aeroplane engineering the problems to be solved have raised fundamental ques- tions in the strength and properties of materials which had never been adequately solved. Some of these questions related to what may be termed theory, and some related to the physical properties of materials. I propose to-day to describe some of these problems, and to suggest the direction in which revision and extension of our fundamental theories and data are required and the lines on which research should be undertaken. Let us consider first one of the oldest materials of construction—timber. Timber was of prime importance in aircraft construction. The first peculiarity of this material which strikes us is that it is anisotropic. Its grain may be used to locate three principal axes—along the grain, radially across the grain, and tangentially across the grain. It is curious that there do not appear to be generally recognised terms for these three fundamental directions. A very few 126 SECTIONAL ADDRESSES. tests are sufficient to show that its strength is enormously greater along the grain than across it. How, then, is an engineer to calculate the strength of a wooden member? There is no theory, in a form available for the engineer, by which the strength of members made of an anisotropic material can be calculated. I fancy I may be told that such a theory is not required—that experience shows that the ordinary theory is quite near enough. How utterly misleading such a statement is I will try to show by a few examples. Suppose a wooden tie or strut is cut from the tree obliquely so that the grain does not lie parallel to its length. In practice it is never possible to ensure that the grain is accurately parallel to the length of the member, and often the deviation is considerable. How much is the member weakened? This comparatively simple problem has been of immense importance in aeroplane construction, and, thanks to the researches made during the war, can be answered. The solution has thrown a flood of light on many failures which before were obscure. If the tensile strengths of a piece of timber are, say, 18,000 lb./sq. in. along the grain and 800 lb./sq. in. across it (radially or tangentially) and the shear strength is 900 lb./sq. in. along the grain—these figures correspond roughly with the strengths of silver spruce—then if a tensile stress be applied at any angle to the grain the components of that stress in the principal directions must not exceed the above strengths, or failure will occur. Thus we can draw curves limiting the stress at any angle to the grain, and similar curves may be drawn for compression stresses. These theoretical curves have been checked experimentally, and the results of the tests confirm them closely, except in one particular. The strengths at small inclination to the grain fall even faster than the theoretical curves would lead us to expect. The very rapid drop in strength for quite small deviations is most striking. Similar curves have been prepared for tensile and compressive stresses inclined in each of the three principal planes for spruce, ash, walnut, and mahogany, so that the strengths of these timbers to resist forces in any direction can now be estimated reasonably accurately. As a second example consider the strength of plywood. Plywood is the name given to wood built up of several thicknesses glued together with the grain in alternate thicknesses running along and across the plank. he result of this crossing of the grain is that the plywood has roughly equal strength along and across the plank. Ply- wood is generally built up of thin veneers, which are cut from the log by slicing them off as the log revolves in a lathe. Owing to the taper in the trunk of the tree and to other irregularities in form, the grain in the veneer rarely runs parallel to the surface, but generally runs through the sheet at a more or less oblique angle. As a consequence the strength of plywood is very variable, and tests show that it is not possible to rely on its having more than half the strength it would have if the grain in the veneers were not oblique. It is therefore obviously possible to improve the manufacture enor- mously by using veneers split off, following the grain, in place of the present sliced veneers. The superiority of split or riven wood over cut wood has been recognised for ages. I believe all ladders and ladder G.—ENGINEERING. 127 rungs are riven. Hurdles, hoops, and laths are other examples. Knees in ships are chosen so that the grain follows the required outline. Owing to the enormous difference in strength in timber along and across the grain, it is obviously important to get the grain in exactly the right direction to bear the loads it has to carry. The most perfect example I ever saw of building up a plywood structure to support all the loads on it was the frame of the German Schutte-Lanz airship, which was made entirely of wood. At the complex junctions of the various girders and ties the wood, which was built up of very thin yeneers—hardly thicker than plane shavings—layers were put on most ingeniously in the direction of every stress. During the war I have had to reject numerous types of built-up struts intended for aeroplanes, because the grain of the wood was in the wrong direction to bear the load. The example shown—a McGruer strut—is one of the most elegant designs, using the grain correctly. Many of the tests applied to timber are wrong in theory and conse- quently misleading. For example, the common method of determining Young’s modulus for timber is to measure the elastic deflection of a beam loaded in the middle and to calculate the modulus by the ordinary theory, neglecting the deflection due to shear, which is legitimate in isotropic materials ; but in timber the shear modulus is very small—for example, in spruce it is only about one-sixtieth of Young’s modulus— and consequently the shear deflection becomes quite appreciable, and the results obtained on test pieces of the common proportions lead to errors in the calculated Young’s modulus of about 10 per cent. The lantern plates show three standard tests; the first is supposed to give the shearing strength of the timber, but these test pieces fail by tension across the grain—not by shearing. Professor Robertson has shown that the true shear strength of spruce is about three times as great as the text-book figures, and has designed a test which gives fairly reliable results. The second figure represents a test intended to give the mean strength across the grain, but the concentration of stress at the grooves is so great that such test pieces fail under less than half the proper load. This fact was shown in a striking manner by narrow- ing a sample of this shape to half its width, when it actually bore a greater total load—i.e., more than double the stress borne by the original sample. The third figure represents a test piece intended to measure the rather vague quality, ‘strength to resist splitting.’ The results actually depend on the tensile strength across the grain, on the elastic constants, and on the accidental position of the bottom of the groove relatively to the spring or autumn wood in the annular rings. Unless the theory is understood, rational tests cannot be devised. There are some valuable tropical timbers whose structure is far more complex than that of our ordinary northern woods. The grain in these timbers grows in alternating spirals—an arrangement which at _ first sight is almost incredible. The most striking example of this type of wood I have seen is the Indian ‘ Poon.’ The sample on the table has been split in a series of tangential planes at varying distances from the centre of the tree, and it will be seen that the grain at one depth is growing in a right-hand spiral round the trunk; a little farther out 128 SECTIONAL ADDRESSES, it grows straight up the trunk; further out again it grows in a left- hand spiral, and this is repeated again and again, with a pitch of about two inches. The timber is strong and probably well adapted for use in large pieces—it somewhat resembles plywood—but it is doubtful whether it is safe in small pieces. No theory is yet available for esti- mating its strength, and very elaborate tests would be needed to determine its reliability in all positions. I had to reject it for aero- planes during the war for want of accurate knowledge of its properties. These examples show how necessary it is to have a theory for the strength of anisotropic materials before we can either understand the causes of their failure or make full use of their properties or even test them rationally. The second material we shall consider is steel, and in dealing with it I do not wish to enter into any of the dozen or so burning questions which are so familiar to all metallurgists and engineers, but to call your attention to a few more fundamental questions. Steel is not strictly isotropic—but we may consider it to be so to-day. The first obvious question the engineer has to answer is, ‘ What is its strength? ’ The usual tests give the Ultimate Strength, Yield Point, Elastic Limit, the Elongation, the Reduction of Area, and perhaps the Brinell and Izod figures. On which of these figures is the dimension of an engine part, which is being designed, to be based? If we choose the Ultimate Strength we must divide it by a large factor of safety—a factor of ignorance. If we choose the Yield Point we must remember that none of the higher-grade steels have any Yield Point, and the nominal Yield Point depends on the fancy of the tester. This entirely imaginary point cannot be used for accurate calculation except in a very few special cases. Can we base our calculation on the Elongation—the Reduction of Area—the Izod test? If we face the question honestly we realise that there is no known connection between the test results and the stress we can safely call on the steel to bear. The only connecting link is that cloak for our ignorance—the factor of safety. I feel confident that the only reliable property on which to base the strength of any engine part is the suitable Fatigue Limit. We have not yet reached the position of being able to specify this figure, but a considerable number of tests show that in a wide range of steels (though there are some unexplained exceptions) the Fatigue Limit for equal + stresses is a little under half the Ultimate Strength, and is independent of the Elastic Limit and nominal Yield Point, so that the Ultimate Strength may be replaced as the most reliable guide to true strength, with a factor—no longer of ignorance, but to give the fatigue limit—of a little over 2. If the Fatigue Limit is accepted as the only sound basis for strength calculation for engine parts, and it is difficult to find any valid objection to it, then it is obvious that there is urgent need for extensive researches in fatigue, for the available data are most meagre. The work is laborious, for there is not one Fatigue Limit, but a continuous series, as the signs and magnitudes of the stresses change. Many problems in connection with fatigue are of great importance and need much fuller G.—ENGINEERING. 129 investigation than they have jso far received—e.g., the effect of speed of testing; the effect of rest and heat treatment in restoring fatigued material; the effect of previous testing at higher or lower stresses on the apparent fatigue limit of a test piece. Some observers have found indications that the material may possibly be strengthened by subject- ing it to an alternating stress below its fatigue limit, so that the results of fatigue tests may depend on whether the limit is approached by increasing the stress or by decreasing it. Improved methods of testing are also needed—particularly methods which will give the results quickly. Stromeyer’s method of measur- ing the first rise of temperature, which indicates that the fatigue limit is passed, as the alternating load is gradually increased, is most promis- ing; it certainly will not give the true fatigue limit in all cases, for it has been shown by Bairstow that with some ranges of stress a finite extension occurs at the beginning of a test and then ceases, under stresses lower than the fatigue limit. But the fatigue limit in that case would not be a safe guide, for finite changes of shape. are not permissible in most machines, so that in that case also Stromeyer’s test may be exactly what is wanted. It can probably be simplified in ‘detail and made practicable for commercial use. Better methods of testing in torsion are also urgently needed, none of those at present used being free from serious defects. Finally, there is a fascinating field for physical research in investigating the internal mechanism of fatigue failure. Some most suggestive results have already been obtained, which extend the results obtained by Ewing. For members of structures which are only subjected to ‘steady loads I suggest ‘that the safe stress might be defined by limiting the corre- ‘sponding permanent set to a small amount—perhaps 4 per cent. or per cent. This principle has been tentatively adopted in some.of \the aircraft material specifications by specifying a Proof Load which must be sustained without a permanent extension of more than 4 per cent. Whether this principle is suitable for all materials and how it will answer in practice remains to be proved by experience. It is at any rate a possible rational ‘basis for determining the useful strength of a material under steady loads. The relation between the proof stress and ‘the shape of the stress- ‘strain diagram is shown in the lantern slide. The curve is the record of an actual test on a certain copper alloy. Ifa length A B correspond- ing'to 4 per cent. elongation be set off along the base line and a line BP be drawn through the point B parallel to the elastic line, to cut the curve in P, then the stress at P is the stress which will give 4 per cent. permanent set. Though 4 per cent. may appear rather a large permanent set to allow it will be seen from the figure that it is less than the elastic elongation would have been at the same stress, and we do not usually find elastic elongations serious. As a commercial test the proof load is very easily applied. For this alloy the ‘specified proof load is shown by the horizontal line so labelled. This load is to (be applied and released, and the permanent extensicn is required by the specification to be less than 4 per-cent. This sample passes the test easily. On the figure the condition for complying with 1920 K 130 SECTIONAL ADDRESSES. the specification is that the curve shall fall above Q. But the test does not require the curve to be determined. If we admit that the fatigue limit is the proper basis for engine- strength calculations, there are a number of interesting modifications required in the common theory of the strength of materials. It will no longer be possible to neglect, as has been so general in the past, the uneven distribution of stress in irregularly shaped parts of machines. It has been generally recognised that sharp corners should be avoided when possible, but no theory is available to enable the stresses at corners to be calculated or to enable their effect on the strength of the member to be estimated. If fatigue is the critical factor in failure under fluc- tuating stresses such theory is most necessary. Hven the roughest guide would be of great value. The nature and magnitude of the con- centrations of stress which occur in practice have been investigated experimentally by Professor Coker by his elegant optical method which has given most valuable results, some of which are already being used in designing offices. If the mathematical theory is too difficult, it may be possible to lay down practical rules deduced from such experimental results—but the method still has many limitations, perhaps the most serious being that it can only be used on flat models. I believe Professor Coker expects to be able to extend the method to round models. As a simple example to show the importance of the subject let us consider the effect of a groove round a straight round bar subject to alternating tension and compression—such a groove as a screw thread. There will be a concentration of stress at the bottom of the groove. The ratio of the stress at the bottom of a groove to the mean stress in the bar has been worked out mathematically by Mr. A. A. Griffith, and his calculations have been confirmed experimentally by his elegant soap- bubble method. The ratio depends on the relation between the depth of the groove, the radius at the bottom, and slightly on the angle between the sides. For a Whitworth form of thread the ratio will be about 3. If the Fatigue Limit is exceeded at the bottom of the groove the metal will fail and a minute crack will form there; this crack will soon spread right across the bar and total failure will result. Thus we see that the safe mean stress in the bar will be reduced to one-third what a plain bar will bear. The truth of this theory regarding the importance of concentrations of stress has still to be proved experi- mentally ; if true, it is of far-reaching importance, since it applies to all concentrations of stress in machine parts subject to fluctuating loads. The theory does not apply to steadily loaded members; in these the local excess of stress is relieved by the stretching of the minute portion which is overloaded, and no further consequences follow. The theory appears to apply to grooves however small, and has an important bearing on the smoothness of the finish of machine parts. The surface of any engine part finished by filing is certainly entirely covered with scratches. Emery likewise leaves the surface scratched— though the scratches are smaller. If, however, polishing be carried further the surface may ultimately be freed from scratches and left in a burnished condition. In this condition amorphous metal has been smeared over the surface—the smooth appearance is not simply due ae G.—ENGINEERING. 131 to the scratches being too small to see. The strength—under alternat- ing stresses—appears to depend on the form of the scratches, and if the ratio of radius at the bottom of the scratch to its depth is fairly large, very little weakening occurs. It seems probable in the ordinary engineer- ing finish produced by emery and oil that the scratches are broad and shallow. This subject is being investigated. A considerable amount of evidence has been collected from practical experience pointing to the important effect which a smooth finish has on the strength of heavily stressed engine parts. Fatigue is probably the cause of failure of wires in wire ropes. A good deal of valuable experimental work has been done on the life of ropes, but so far as I am aware there is no satisfactory theory of their strength. This subject also requires research, and it seems probable that valuable practical results might follow if the true explanation of the cause of the breakages of the wires was determined. These are only examples, but they may be sufficient to show how much work both experimental and theoretical requires to be done to give the engineer a really sound basis for the simplest strength calcula- tions on any moving machinery. But there are more fundamental questions still which must be tackled before the simplest questions of all which meet the engineer can be answered scientifically. The two most urgent and most important questions which I met with during the war in connection with aircraft were always the same—Why did some part break? and, What is the best material to use for that part? It was most disconcerting to find how inadequate one’s knowledge was to answer these two simple questions. The common answers are: To the first: ‘It broke because it was too weak, make it stronger,’ and to the second: ‘ General practice indicates such a material as the best—better not try any other or you may have trouble.’ In aircraft weight is paramount, and to make a part stronger—t.e., heavier—had to be the last resort, and when used was almost a confession of failure. ‘ General practice’ was no guide in aeroplane engines, which are built of the strangest materials. The origins of fractures were traced to many causes, often lying far away from the site of the breakage; but with these I am not concerned to-day. I wish to confine our consideration to the actual fracture and to ask, ‘ What stress caused the fracture?’ and “What property of the metal was absent which would have enabled it to withstand that stress?’ And again, ‘ What other material pos- sesses suitable properties to withstand the stresses better?’ These are the fundamental questions which I have referred to—and which urgently need answers. As an example I will take a broken propeller shaft. It has broken in a beautiful spiral fracture. What stress causes that? T have failed to explain it by any of the facts I know about the steel it is made of. It is, of course, a fatigue fracture—i.e., it spread gradually. The questions to be answered are, Did it fail under tension, bending or torsion? and, Why was a spiral direction followed by the failure as it spread ? riety _ It may be objected that the question is unimportant. TI think not. For example, till we can determine the nature of the stress we cannot Kk 2 132 SECTIONAL ADDRESSES. indicate the nature of the load—thus I cannot say if it broke under a torsional load (possibly torsional vibration) or under a bending load (possibly due to some periodic variation of thrust on one of the pro- peller blades as it passed an obstruction). Until the nature of the load which caused the failure is known, it is very difficult to take steps to guard against similar accidents. For the most urgent reasons, there- fore, we require to be able to understand the fracture, as in nearly all aircraft problems men’s lives hang on the answer. Turning now to the question of the most suitable material, I will take as an example the material for the crankshaft of an aeroplane engine. A few months before the Armistice there were difficulties in gefting sufficient supplies of the high-grade nickel-chrome steel forgings then in general use for shafts, and proposals were made to use a plain carbon steel. Such a steel would be about 30 per cent. weaker, accord- ing to the ordinary tests. A conference of leading metallurgists and engineers was held to discuss the suggestion. No one present ventured to predict whether the weaker steel would answer or not, or whether the dimensions would have to be increased or not. It was pointed out that a French engine was now using 50-ton steel with better results than when using the 100-ton steel for which it was designed, no changes in dimensions having been made. Such a reduction of strength might be understood in ordinary engineering where there are large margins of safety, but in an aeroplane engine, in which every ounce of metal is cut off which can be spared, they show how completely ignorant engineers are of what the suitability of material depends on. As another example, Why are oxygen cylinders annealed—repeat- edly? Annealing reduces the steel to its weakest condition. I believe the fondness for annealing is due to our ignorance of the properties we require. Perhaps the quality of steel which an engineer fears most is brittleness. He believes that annealing will soften it and reduce the brittleness; so he anneals, blindly. The fact is that we do not know what brittleness is—we cannot define it—we cannot measure it— though there are endless empirical tests to detect it. Till we know what it means and can measure it we are in a miserable position. During the war I was consulted on what could be done to reduce the enormous weight of oxygen cylinders, and I advised that experiments should be made on the high-quality alloyed steel tubes we were using in aircraft construction. The department dealing with these tubes took the matter up, and alloyed steel cylinders, properly heat-treated, were made. These were, I believe, a success, and only weighed a small fraction of the old-fashioned cylinders. But my suggestion was little more than a guess, and no means was known of accurately testing the suitability of the material, so they were only accepted after passing any number of empirical tests, consisting of various kinds of rough usage, to see if they would crack or burst. Surely an engineer should be able to sav whether a cylinder. is safe without dropping it from the roof or rolling it down the front-door steps to see if it breaks. These examples refer only to different grades of the same material— steel—but how far worse off we are when the problem is whether some other alloy would be suitable to replace steel. Proposals have been — _@,=-ENGINEERING. 133. made, for example, to, replace the very hard steel used at present for connecting-rods by duralumin or some other forged aluminium alloy. It seems worth trying; but who, in our present state of ignorance of the real properties of metals, will say if the experiment will be a success ? How difficult it is to prophesy may be illustrated by the results of two empirical tests on duralumin and steel sheets of the same thick- nesses. ‘he ultimate strengths and elongations of the steel and the duralumin were roughly equal. ‘Ihe lantern slides show that under reverse-bend tests they both follow the same law, the steel being the better. But under the cupping test they follow opposite laws. The suitability of different materials presumably depends on their fundamental physical properties. These may be many, but some physicists think that they are probably really very few, and that, knowing these few, it may be possible to deduce all the complex properties required by the engineer and to state with certainty how materials will behave under any conditions of service. This is the most fundamental problem which needs solution to enable the knowledge of the strength of materials to be put on a sound foundation. It will need the co-operation of able physicists, metallurgists, and engineers to solve it. While urging the importance of research in the fundamental theories of stress and fundamental properties of materials, I wish to lay special stress on the nature of the researches required. Engineers are intensely practical men, and their practice has generally been ahead of their theory. The difficulties they have met have been dealt with, often with the greatest ingenuity and skill, as special problems. They have seldom had time or opportunity to solve the general problems, and as a result they are used to making their experiments and trials as close a copy— usually on a smaller scale—of the real thing as possible. The results obtained in this way, while they are applicable to the particular problem, are of little general use. They depend on many factors. The researches I am now advocating must be of a diametrically opposite description. They must be absolutely general, and the results must depend on one factor only at a time, so that general laws may be established which will be applicable to all special problems. There are many other similar gaps in our knowledge to which I have not time to refer to to-day. I have tried to show that we need most of all a real knowledge of the fundamental properties of materials, from which we shall be able to deduce their behaviour in any condition of service, so that we may be able to compare the relative merits of diverse materials for any particular purpose. _ Secondly, that we need a practical method of calculating the stresses in parts of any form, so that concentrations of stress may be avoided or that their magnitudes may be known and allowed for. Thirdly, that we need a rational connecting link between the tests made on materials and the stresses they will bear in service, to replace the factor of safety. I have suggested two tests, the Proof Load and the Fatigue Limit, which might be used directly in estimating the allow- able working stress. 184 SECTIONAL ADDRESSES. Fourthly, that we need a mathematical theory for the strength of anisotropic materials, of which timber is an extreme and important example. When the notes for this address were first drafted I ended by an appeal to the Board of Scientific and Industrial Research to undertake the necessary research work. Since then the Aeronautical Research Committee has been constituted, and a sub-committee has been appointed to deal with ‘ Materials.’ I have great hopes that the committee will tackle many of these problems. I will therefore conclude by appealing to all who can help to assist that committee in their endeavour to solve these most important and fascinating, but most difficult, problems. SECTION H: CARDIFF, 1920. ADDRESS TO THE ANTHROPOLOGICAL SECTION BY Pror. KARL PEARSON, M.A., LL.D., F.RB.S., PRESIDENT OF THE SECTION, Anthropology—the Understanding of Man—should be, if Pierre Charron were correct, the true science and the true study of mankind.* We might anticipate that in our days—in this era of science—anthro- pology in its broadest sense would occupy the same exalted position that theology occupied in the Middle Ages. We should hail it ‘ Queen of the Sciences,’ the crowning study of the academic curriculum. Why is it that we are Section H and not Section A? If the answer be given that such is the result of historic evolution, can we still be satisfied with the position that anthropology at present takes up in our British Universities and in our learned societies? Have our univer- sities, one and all, anthropological institutes well filled with enthusi- astic students, and are there brilliant professors and lecturers teaching them not only to understand man’s past, but to use that knowledge to forward his future? Have we men trained during a long life of study and research to represent our science in the arena, or do we largely trust to dilettanti—to retired civil servants, to untrained travellers or colonial medical men for our knowledge, and to the anatomist, the sur- geon, or the archeologist for our teaching? Needless to say, that for the study of man we require the better part of many sciences, we must draw for contributions on medicine, on zoology, on anatomy, on archeology, on folk-lore and travel-lore, nay, on history, psychology, geology, and many other branches of knowledge. But a hotch- potch of the facts of these sciences does not create anthropology. The true anthropologist is not the man who has merely a wide knowledge of the conclusions of other sciences, he is the man who grasps their bearing on mankind and throws light on the past and present factors of human evolution from that knowledge. 1 “‘Ta vraye science et le vray estude de l’homme c’est l’Homme.’’ Pierre Charron, De la Sagesse, Préface du Premier Livre, 1601.. Pope, with his ‘‘ The proper study of mankind is Man,” 1733, was, as we might anticipate, only a plagiarist. 136 wis * SECTIONAL ADDRESSES. | I am afraid I am a scientific heretic—an outcast from the true ortho- dox faith—I do not believe in science for its own sake. I believe only in science for man’s sake. You will hear on every side the argument that it is not the aim of science to be utile, that you must pursue scientific studies for their own sake and not for the utility of the resulting dis- coveries. I think that there is a great deal of obscurity about this attitude, I will not say nonsense. [I find the strongest supporters of ‘science for its own sake ’ use as the main argument for the pursuit of not immediately utile researches that these researches will be useful some day, that we can never be certain when they will turn out to be of advantage to mankind. Or, again, they will appeal to non-utile branches of science as providing a splendid intellectual training—as if the provision of highly trained minds was not itself a social function of the greatest utility! In other words, the argument from utility is in both cases indirectly applied to justify the study of science for its own sake. In the old days: the study of hyperspace—space of higher dimensions than that of which we have physical cognisance—used to be cited as an example of! a non-utile scientific research. In view of the facts: (i.) that our whole physical outlook on the universe—and with it I will add our whole philosophical and theological outlooks—are taking new aspects under the theory of Einstein; and (ii.) that study of the relative influences of Nature and Nurture in Man can be reduced to the trigonometry of polyhedra in hyperspace—we see how idle it is to fence off any field of scientific investigation as non-utile. Yet are we to defend the past of anthropology—and, in particular, of anthropometry—as the devotion of our science to an immediate non- utile which one day is going to be utile in a glorious and epoch-making manner, like the Clifford-Hinstein suggestion of the curvature of our space? I fear we can take no such flattering unction to our souls. I fear that ‘the best is yet to be’ cannot be said of our multitudinous observations on ‘ height-sitting’ or on the censuses of eye or hair colours of our population. These things are dead almost from the day of their record. It is not only because the bulk of their recorders were untrained to observe and measure with scientific accuracy, it is not only because the records in nine out of ten cases omit the associated factors without which the record is valueless. It is because the progress of mankind in its present stage depends on characters wholly different from those which have so largely occupied the anthropologist’s atten- tion, Seizing the superficial and easy to observe, he has let slip the more subtle and elusive qualities on which progress, on which national fitness for this or that task essentially depends. The pulse-tracing, the reaction-time, the mental age of the men under his control are far more important to the commanding officer—nay, I will add, to the employer of labour—than any record of span, of head-measurement, or pigmentation categories. The psycho-physical and psycho-physio- logical characters are of far greater weight in the struggle of nations to-day than the, superficial measurements of man’s body. Physique, im the: fullest. sense, counts; something still, but. it is. physique as méasured by health, not by stature or eye-colour. But character, strength of will, mental quickness count more, and if anthropometry 7. . H.—ANTHROPOLOGY. Brie 137 is to be useful to the State it must turn from these rusty old weapons, these measurements of stature and records of eye-colour to more certain appreciations of bodily health and mental apfitude—to what we may term ‘ vigorimetry ’ and to psychometry. Some of you may be inclined to ask: And how do you know that these superficial size-, shape-, and pigment-characters are not closely associated with measurements of soundness of body and soundness of mind? The answer to this question is twofold, and I must ask you to follow me for a moment into what appears a totally different sub- ject. I refer to a‘ pure race.’ Some biologists apparently believe they can isolate a pure race, but in the case of man, I feel sure that purity of race is a merely relative term. For a given character one race is purer than a second, if the scientific measure of variation of that character is less than it is in the second. In loose wording, for we cannot express ourselves accurately without mathematical symbols, that race is purer for which on the average the individuals are: closer to type for the bulk of ascertainable characters than are the characters in a second race. But an absolutely pure race in man defies definition. The more isolated a group of men has remained, the longer it has lived under the same environment, and the more limited its habitat, the less variation from type it will exhibit, and we can legitimately speak of it as possessing greater purity. We, most of us, probably believe in a single origin of man. But as anthropologists we are inclined to speak as if at the dawn of history there were a number of pure races, each with definite physical and mental characteristics; if this were true, which I do not believe, it could only mean that up: to that period there had been extreme isolation, extremely differentiated environments, and so marked differences in the direction and rate of mental and physical evolution. But what we know historically of folk-wanderings, folk-mixings, and folk-absorptions have undoubtedly been going on for hundreds of thousands of years, of which we know only a small historic fragment. Have we any real reason for suppos- ing that ‘ purity of race’ existed up to the beginning of history, and that we have all got badly mixed up since? Let us, however, grant that there were purer races at the beginning of history than we find to-day. Let us suppose a Nordic race with a certain stature, a given pigmentation, a given shape of head, and a given mentality. And, again, we will suppose an Alpine race, differ- ing markedly in type from the Nordic race. What happens if we cross members of the two races and proceed to a race of hybrids? 4 0 & i) oe) ~I Ln i) or oO o =) Daily Horl. Wave Date Difference, Wind Motion of |Amplitude P sod F Sec. Direction the Wind, & ‘Seo ; Miles ra 1920 Jan. 31 0-0 S—WSW 427 58 73 Feb. 2 0:0 SW—S 587 4:0 7°5 » 6 15 SSE 295 2°8 67 ” 9 10 WSW 491 3:2 63 » 10 10 SW 670 95 8:0 » 12 0:0 WNW —S 354 3°6 6:2 » 15 15 8 423 5:0 62 tl el ak brill peel te eT mat ede Al co sgl AO beh Nl bata ate 220 REPORTS ON THE STATE OF SCIENCE, ETC.—1920. By Second Method. Daily Horl. ee Dat Difference, Wind Motion of | Amplitude Pe ie d Ve Sec. Direction the Wind, Ie Saline Miles BAG: 1920 March 4 1:0 WSW—S 260 4:9 75 Ss 5 1:0 8 285 16 6-7 ” 6 0°75 NS) 476 4:5 6°0 :° 9 ==" W 178 = a7 » 10 07 SSW 272 7:0 7:0 rer sii 11 NW 257 4:9 6°5 babe, plies 0:5 W 541 57 6:0 elisa) 1:0 S) 377 4:5 6°2 he les 0:8 WwW 500 4:0 67 » 20 — W 131 08 5:5 pee a 08 Sy 348 4:0 7°3 9», 20 07 s 613 53 73 » 28 08 rs) 498 32 57 Average 83 371 3°9 6°5 It will be observed that the time in column two is generally about one second, which is the approximate time required for a surface wave to travel two miles, thus indicating that the direction of propagation was more or less constant and approximately from north to south. On the other hand there are differences ranging between 0°7 sec. and 1°1 sec. Remembering the method of synchronising the clocks it is possible many of the irregularities are due to personal and instrumental error. To what extent they indicate that the azimuth wanders round the northern semicircle it is difficult to determine, but from the fact that the southern half was never indicated, it would seem feasible to presume that the waves came generally from the north. More precise information is very desirable, and can only be obtained from not less than three stations with preferably a longer base of operation, and with better timing facilities. It is hoped, at some future date, when three machines are simultaneously available and suitable quarters and observers found, to make the experiment on a ten-mile triangle. An attempt was made to identify the microseisms recorded at Oxford with those of West Bromwich (80 miles apart), but unfortunately the booms are oriented 90° from each other. From some measures made by Professor Turner there was a suggestion of agreement, but nothing really tangible has at present been. detected. A fruitful investigation for observatories would be to determine whether this unidirectional character of microseisms is general, and whether the azimuth depends upon the contour or physical features of a country. From the foregoing it is clear that microseisms are real travelling waves of the same character as those propagated by earthquake shocks, and if a seismograph fails to perceive them then it is not recording all that is passing. Two stations where Milne-Shaw instruments are installed, viz., Bidston and Edinburgh, seem to be very liable to microseisms. Both stations are near the sea, and both stand upon the crest of a hill. Shide was within six miles of the open sea, but did not stand upon a hill. This station did not find the microseisms more prevalent than an average station. Oxford and West Bromwich are well removed from the sea. They record microseisms as freely as Shide. It has yet to be determined whether the sea. board is more liable to these movements : the evidence points to that conclusion. SEISMOLOGICAL INVESTIGATIONS. 221 The P phase of a seismogram sometimes, but not often, begins with a sharp kick—denoted i P; but sensitive machines show that much more frequently this sharp kick is preceded by two or three waves of smaller amplitude and higher frequency. When the frequency is distinctly quicker than that of the prevail- ing microseisms, and the amplitude of the latter is not too great, it is easy to detect the true P as a superimposed wave, but if the period of these small precursors approximate to that of the microseisms, then it is difficult to deter- mine the true inception of the earthquake record. Machines which do not record the microseisms will not record these minute waves. With such machines probably more uniformity, by reading the bigger kick, will result, but misguided uniformity will not be conducive to obtaining the true rate of propagation of the P phase. It is to sensitive machines and careful scrutiny of the record that we must look for data for the perfecting of seismological tables. 929, REPORTS ON THE STATE OF SCIENCE.—1920. Absorption Spectra of Organic Compounds.—Report of Committee (Sir J. J. Dossiz, Chairman; Professor E. E. C. Baty, Secretary; and Dr. A. W. Stewart). Drawn up by the Secretary. Various theories have been advanced from time to time to explain the absorption bands exhibited by organic compounds, and it would seem advisable at this time to deal with these and to state the position that has been reached in this branch of scientific investigation. There is no doubt that the pioneer in this field of work was the late Sir Walter Noel Hartley. He was the first to undertake a detailed investigation on scientific lines of the absorption exerted by organic compounds in the visible and ultra-violet regions of the spectrum. He was the first to recognise the fact that isolated measurements of the absorption spectrum of a substance in solution are valueless, and he devised the method whereby com- plete records of the absorption could be obtained. Hartley’s method consisted in measuring the oscillation frequencies of the light for which complete absorption is shown by definite thicknesses of a solution of known strength of the sub- stance. The observations were repeated with the same thicknesses of more and more dilute solutions until no measurable absorption was observed. By plotting the oscillation frequencies against the thicknesses expressed as equivalent thick- nesses of some selected concentration an absorption curve was obtained, called by Hartley a molecular curve of absorption. At the present time this method of observation has been displaced by the quantitative measurement of the light absorbed. The absorptive power exhibited by a given substance for light of a given frequency is expressed in terms of the molecular extinction coefficient, log Io/I+dc, where Io/I is the ratio of the intensities of the incident and emergent light as observed with a layer d cms thick of a solution containing c¢ gram molecules of the absorbing substance dissolved in a litre of some diactinic solvent. Reference may: be made to the use of a solution of the substance under examination. In general it may be said that the absorptive power exerted by compounds is large, with the result that it is necessary to use very thin layers for purposes of observation. This is impossible of realisation with solid sub- stances, and indeed with many liquids the thickness required is so small that without very accurate and expensive apparatus the necessary thin layers cannot be obtained. By common consent, therefore, solutions of known strength in diactinic solvents are employed. It must be remembered, however, that the influence of a solvent on the absorptive power of a compound is often very marked, and due allowance must be made for this effect. The question of the influence of a solvent will be discussed later. The region of the spectrum dealt with by Hartley extended from the red end to the limit of the ultra-violet as set by a quartz spectrograph working in air, that is to say, between the limits of wave-length 6000 and 2100 Angstroms. He showed in the first place that substances can in general be divided into two classes, namely, those which exhibit selective absorption, z.e., absorption bands between the above spectral limits, and those which exhibit only general absorp- tion. It is not necessary here to detail the whole of Hartley’s work, but one important fact was established, namely, that, providing no disturbing factor intervenes, the absorption curves shown by compounds of similar constitution are themselves similar. This fact was made use of in determining the constitution of a few substances with reference to which the chemical arguments at the time were at fault. It was shown for instance that phloroglucinol is a true trihydroxy- benzene and not ketonic since its absorption curve is very similar to that of its co trimethyl ether.' Similarly the constitution of isatin CoH Seo, NH 1 See references, p. 243, ON ABSORPTION SPECTRA OF ORGANIC COMPOUNDS. 223 CH=CH O carbostyril? ON and 0-oxycarbanii® oHK Seo, was determined NH NH—CO by comparison of their absorption curves with those of their nitrogen and oxygen methyl derivatives. It may readily be understood that high hopes were engendered that this method might prove to be of immense value to the chemist as independent evi- dence in the determination of the constitution of compounds, but it may be said at once that these high hopes have not been realised. A very brief account may be given of the various attempts that have been made to co-ordinate consti- tution and absorption of light, because all of these attempts have some importance in relation to more recent developments. Following on Hartley’s successful work an attempt was made to determine the constitution of ethyl acetoacetate and its metallic derivatives by comparison with its two ethyl derivatives, ethyl B-ethoxycrotonate and ethyl ethylacetoacetate.* It was found, however, that the parent ester and its metallic derivatives differ in absorptive power very materially from the two isomeric ethyl derivatives. The two latter do not show selective absorption, whilst the metallic derivatives show well-marked absorption bands. The deduction was made from this that the origin of the absorption bands is to be found not in any specific structure but in a tautomeric equilibrium between the two forms, that is to say, the selective absorption of light is due to O OM tl | the change of linking involved in the process—C—CHM—+—C=CH_, where M stands for hydrogen or a metal. This theory was extended to aromatic compounds where the selective absorp- tion was considered to be due to the oscillation of linking supposed to be present in the benzene ring. The absence of selective absorption observed with some benzenoid compounds was considered to be due to the restraint on the oscillation exercised by certain strongly electro-negative substituent groups such as NO,, &e.> i Without question one of the most important theories connoting absorption and structure is that known as the quinonoid theory which connected visible colour with a structure analogous to that of either para- or ortho-benzoquinone. This theory has found great favour on account of the undoubted fact that when a quinonoid structure is possible the substance in the majority of cases is visibly coloured, whilst in the case of an isomeric substance in which a quinonoid struc- ture is not possible the colour is in general less intense or indeed very slight. It was a simple matter to apply the oscillation theory in explaining the visible -colour of the quinonoid compounds. The oscillation was suggested as that between the two forms oO o—— I | —— er 5 O | o—— Similarly the visible colour of the o-diketones was explained by the oscillation 00 o-0O ol jy ar between the two forms —C—C— Pil —C=C-—, which after all is only a slight varia- tion of the quinonoid conception. This particular type of oscillating linking was named isorropesis.® It was soon pointed out, however, that this theory was open to serious objection because certain compounds in which no oscillation seemed possible 99.4 REPORTS ON THE STATE OF SCIENCE.—1920. CH, exhibit strong selective absorption. For example camphor 7 CoB. shows ; CO a marked band, as also does the disubstituted compound 8 is Gi] Dre Co in which no tautomeric equilibrium seems possible. Again, azo-iso-butyronitrile shows marked selective absorption. aah Sega C—-N=N- Pleas sf a CH, CN NC The most interesting example of a compound which exhibits an absorption band is chloropicrin, CC1,NO,, which does not contain any hydrogen atoms at all. It may be noted that Hantzsch has taken up the position that there is a definite correlation between constitution and absorption, and he has published very many papers in support of his theory. The starting-point of the theory is the derivatives of ethyl acetoacetate which have already been referred to. He showed that ethyl dimethylacetoacetate, which is an absolutely definite ketonic compound, exhibits only slight general absorption. The enolic derivative ethyl B-ethoxycrotonate at equal molecular concentration exhibits more strongly marked general absorption. Hantzsch assumes® that the absorption curves are truly characteristic of the ketonic and enolic forms respectively. He then assumes that the absorption band shown by the metallic derivatives of ethyl acetoacetate is due to the constitution where M stands for a monovalent metal. The novelty bs C yh io, H,C oO | | C M Ge ee of the conception lies in the mutual influence of the secondary valencies or residual affinities of the metal and oxygen atoms, this influence being denoted by the dotted line in the formula. It will be seen that this explanation of selective absorption does not involve any liable atoms but attributes the phenomenon to secondary valencies. Starting from this original assumption Hantzsch has built up a complete theory of a direct correlation between absorp- tion and constitution which states that if a substan¢e exhibits different absorption curves under different conditions of solvent, &c., this is due to a definite change in constitution. It is not worth while to describe in detail the conclusions which Hantzsch arrives at as regards the specific compounds examined by him,?° such, for instance, as the variety of absorption bands shown by compounds of an acid type when dissolved in different basic solvents, each different absorption band being attributed to a different structure of the compound. It is perhaps worthy of mention that Hantzsch finds it necessary to confess that in some cases the variations in absorption shown by certain compounds are more numerous than can be accounted for by changes in constitution. It may be stated at once that there are several very grave objections to LS ON ABSORPTION SPECTRA OF ORGANIC COMPOUNDS. 995 Hantzsch’s theory, and indeed these are so fundamental that it becomes impos- sible to accept the theory as it stands. In the first place, as was pointed out above, the cardinal assumption on which the whole theory rests is that the absorp- tion band shown by the metallic derivatives of ethyl acetoacetate is due to the secondary valencies of the metallic atom and the carbonyl oxygen of the carboxyl group. There are many cases of compounds in which secondary valencies must be postulated in order to explain their very existence, and these compounds do not generally show absorption bands in the visible and ultra- violet. Some peculiar merit must therefore be attributed to the six-membered ‘ring’ of Hantzsch’s formula, and it is difficult to accept this since the selective absorption of such compounds as the alkaline nitrates and chloropicrin obviously cannot have any relation to a six-membered ring. More important still are two facts which appear to have escaped the notice of Hantzsch. First, ethyl dimethylacetoacetate in the presence of alkali shows an absorption band very similar to that shown by ethyl acetoacetate in the presence of alkali. Second, ethyl B-ethoxycrotonate shows an incipient absorp- tion band in the presence of acid. It is obvious that these two observations are in direct opposition. to the Hantzsch formula as the correct explanation of the selective absorption shown by the metallic derivatives of ethyl acetoacetate. Still more cogent arguments against the theory of correlation between structure and absorption in the visible and ultra-violet are to be found in such cases as pyridine and piperidine. Pyridine in the homogeneous state and in solution in various solvents exhibits an absorption band with centre at 1/A = 3910, but in the vapour state it shows an entirely different band with centre at 1/A = 3587.1! Piperidine vapour shows a well-marked absorption band, but in solution and in the homogeneous state it is completely diactinic. Analogous dissimilarities between the molecular absorptive powers of liquid and vapour have been observed with other compounds, and clearly on the structure-absorption theory the structure of the molecules in the liquid and vapour phases must be different. This would seem to be impossible at any rate in the case of symmetrical molecules such as pyridine and piperidine. The evidence against the direct structure-absorption correlation theory as developed by Hantzsch is overwhelmingly great, and this is equally true of the quinonoid explanation of visible colour. The evidence of numerous colourless compounds which cannot be quinonoid in structure is sufficient to condemn this theory, even were there no other evidence against it. One of the most often quoted instances in which the quinonoid theory is invoked is the well-known case of aminoazobenzene. This compound gives with hydrochloric acid (one equivalent) a salt which is more highly coloured than it is itself. This is universally accepted as being due to the salt having the structure ==, because the colour and absorption spectrum is entirely different from that of benzeneazophenyltrimethylammonium iodide. lin Bot pea which of course corresponds to the normal form of the hydrochloride. H,; OD _ On the other hand, the trimethylammonium compound also gives a salt which is more highly coloured than it is itgelf, and obviously this cannot be due to a quinonoid structure, It is clearly unjustifiable to explain the one case of colour 1920 ee ; Q 996 REPORTS ON THE STATE OF SCIENCE.—1920. change by the quinonoid configuration when the other case of exactly analogous colour change cannot be so explained. Another well-known application of the quinonoid hypothesis is to the alkali metal salts of the nitrophenols which are highly coloured. It is stated, for example, that the sodium salt of p-nitrophenol has the constitution O O= == xt ONa If that is so, what is the constitution of the nitrophenol when in solution in concentrated sulphuric acid, for it is equally coloured under these conditions? A similar coloured solution is obtained when p-nitroanisole is dissolved in sulphuric acid. Many other instances could be quoted, and there is no doubt that the evidence against a direct structure-absorption correlation is overwhelmingly great. There are two general objectives to any of the theories that have been referred to. In the first place, no theory can be sound which is limited to a very minute section of the spectrum such as the visible and ultra-violet, and in the second place, no theory can hold good unless it rests on a quantitative physical basis. There is also another aspect of the phenomenon of absorption, namely, its un- doubted connection with the phenomena of fluorescence and phosphorescence. Just as the selective absorption of light must be due to specific properties of molecules, so also must the emission of light by molecules be due to similar properties. It is evident that any theory must take cognisance of both phenomena. It is true that many theories were advanced to explain the fluorescence of organic compounds, but none of these can be said to hold the field. Devised to explain visible fluorescence they fail entirely to offer any explanation of the ultra-violet fluorescence shown by many compounds, In general it may be said that the most recent work on the absorption by organic compounds has increasingly shown that there is some relation between the absorption bands shown by a substance and its reactivity. Perhaps the first observations which supported this view were those of certain amino-aldehydes and -ketones of the aromatic series and their salts with hydrogen chloride.12_ It was found that alcoholic solutions of these compounds exhibit well-marked absorption bands. On the addition of small quantities (0°1 to 0°5 eq.) of hydro- chloric acid to these solutions a new absorption band, situated nearer to the red, is developed in each case. On the addition of more acid this band disappears and gives place to the absorption characteristic of the hydrochloride of the original base. This shows that the base as it exists in alcohol solution does not react with the acid to give the salt, but that it is first converted into an inter- mediate or reactive phase which then reacts with more acid to give the salt. These observations were extended to many substances, notably certain phenolic compounds including the nitrophenols.1* The compounds in alcoholic solution exhibit well-marked absorption bands which are not appreciably changed when sulphuric acid is added. When dissolved in concentrated sulphuric acid they develop visible colour due to absorption bands in the visible region. The compounds in sulphuric acid solution, on being allowed to remain, slowly undergo sulphonation to give colourless sulphonic acids. Clearly. therefore, these phenols in the condition in which they exist in alcoholic solution do not react with sulphuric acid. When dissolved in strong sulphuric acid they are changed into a reactive phase which slowly reacts with the sulphuric acid to give the sulphonic acid. They are therefore exactly analogous to the amino-aldehydes and -ketones alreadv mentioned. It might easily be said that the coloured reactive modifications have under- gone a change in structure. but further evidence shows that no change of structure has taken place. The majority of these compounds in alcoholic solu- tion exhibit fluorescence when exposed to light of frequency equal to that of their absorption bands. The frequency of this fluorescent emission has been accurately measured, and it has been found in every case of the above-mentioned substances that the frequency of the fluorescence of the compound in alcoholic ON ABSORPTION SPECTRA OF ORGANIC COMPOUNDS. 227 solution is equal to that of the absorption band shown by that compound when in the reactive phase. The same frequency therefore is characteristic of a given substance in two solvents, in one of which it is exhibited as emission and in the other as absorption. It is evident, therefore, that the constitution of each compound is the same in the two cases. Very important conclusions may be drawn from these observations, namely, that a given compound can exist in at any rate two phases which differ in their reactivity and which are characterised by different absorption bands. Also the absorption bands shown by the reactive phases are nearer to the red end of the spectrum. It is therefore an obvious deduction that a definite absorption band is associated with a definite type of reactivity. The next question to consider is whether an explanation of these facts can be found. In the theories of absorption spectra given above no reference is made to the ultimate destination of the light which is being absorbed. It is perfectly obvious that, unless the absorbing compound undergoes a photochemical change, the total amount of energy absorbed must again be radiated. It is equally evident that just as the light energy is absorbed at frequencies which are characteristic of the absorbing substance, so also must this energy be radiated at frequencies characteristic of the substance. Careful experiments have proved that, provided the absorbing substance or its solution is free from dust, there is no evidence of radiation at the frequencies which lie within the absorption band. Clearly, therefore, the phenomenon of absorption is not one of optical resonance, that is to say, the light energy absorbed by a substance is radiated at frequencies which are not the same as those at which it has been absorbed. Except in those cases where fluorescence or phosphorescence is observed, the whole of the absorbed energy is radiated at frequencies which lie in the infra-red region of the spectrum, and we have therefore— Energy absorbed (visible or ultra-violet) = energy radiated (infra-red), This necessarily establishes a relationship between the various frequencies exhibited by a substance in the infra-red, visible, and ultra-violet regions, and, indeed, invites investigation of this relationship. It will be remembered that Planck formulated the theory that absorption and radiation of energy are not continuous processes, but are discontinuous in the sense that the energy is absorbed or emitted in a series of fixed amounts. To these fixed amounts he gave the name of energy quanta, and he showed that the size of the quantum is given by the product of the frequency into a universal constant, the most recent value of which is 656 x 1027. According to this theory, therefore, if a substance is absorbing light with a frequency of, say, 9 x 1014, the process is not continuous, but each molecule absorbs a series of quanta, each of which is 9 x 10!4 x 656 x 107, or 5:904 x 107 ergs. Without discussion of the fundamental basis of this quantus theory it may be applied to the problem of the absorption and radiation of energy by a molecule when, as already explained, the total quantity of energy absorbed is radiated at another and smaller frequency. Let a molecule absorb one quantum of light energy at its absorbing frequency. This energy is then radiated at another ‘and smaller frequency, but it must be radiated as a whole number of quanta at ‘that frequency. It follows, therefore, that when a molecule is absorbing at one frequency and radiating at another and smaller frequency, one quantum of energy at the larger frequency must be equal to a whole number of quanta at ‘the smaller frequency. Finally, since the quantum is the product of the fre- ‘quency into the universal constant, the conclusion is reached that the absorbing frequency must be an exact multiple of the radiating frequency. In other words, ‘the frequencies of each absorption band shown by a substance. in the visible ‘and ultra-violet must, on the basis of Planck’s theory, be an exact multiple of a frequency characteristic of that substance in the infra-red. It was not difficult ‘to test the validity of this deduction since the existence of characteristic frequencies in the infra-red possessed by a substance can be proved by the method of absorption spectra observations in that region, and indeed a creat number of substances had already been in vestigated in this manner. . Tt may be stated’ at once that the relation has been found to be true in the Q 2 228 REPORTS ON THE STATE OF SCIENCE.—1920. case of every substance examined.‘ Further than this, it is well known that certain substances exhibit more than one absorption band in the visible or ultra- violet, and it has been found that the frequencies of each,of these absorption bands are exact multiples of one and the same frequency characteristic of that substance in the infra-red. It follows, therefore, that when a substance shows more than two absorption bands in the visible or ultra-violet there must exist a constant difference between the frequencies of consecutive bands, and this difference must equal the fundamental infra-red frequency. This has also been proved to be true. The application of the Planck theory has led to the discovery of relationships between the frequencies of the absorption bands shown by a substance, relation- ships which are of considerable importance because they form a quantitative basis of molecular frequencies. It is not possible here to give the mathematical development of Planck’s theory, and the theory is only mentioned because it led to the discovery of the relation between the frequencies. It is advisable at this point to discuss in some detail what is meant by the frequency of an absorption band and also the influence of a solvent upon that frequency. It is common knowledge that in many instances under high resolving power an absorption band is found to possess a structure. The most common phenomenon is when an absorption band consists of a series of sub-groups. In this case one sub-group always exhibits a maximum absorptive power, and those on either side exhibit decreasing absorptive power the farther they are situated from the principal sub-group. Then, again, it is generally found by the examination of the vapour of the substance that each of the sub-groups is resolved into fine absorption lines, and that the arrangement of these lines as regards their intensity is analogous to that of the sub-groups themselves. There is always in each sub-group one line of maximum intensity, and the other lines are arranged in series of decreasing intensity with regard to this central line. Now when a substance is cooled to low temperatures it is found that its absorption bands become narrower, this being due to the suppression of the outermost sub-groups. With further fall of temperature more and more sub- groups disappear, and finally there is left only the principal line of the principal sub-group. This absorption line persists even at the lowest temperatures yet reached. It is perfectly evident therefore that this single frequency is truly characteristic of the molecules, and that the other frequencies which make up the breadth of the band are due to some cause connected with the temperature of the molecules. There is, of course, no necessity to cool a substance to low temperatures in order to recognise the true molecular frequency, because this frequency is always that one for which the absorptive power is the greatest in the absorption band. In the quantitative relationships given above it is this true molecular frequency which is referred to. It is perhaps not out of place to refer to the confusion that has arisen from time to time from carelessness in nomenclature in dealing with absorption spectra observations. The term ‘band’ is applied to the whole region covered by one set of associated groups or sub-groups. In the literature the word band has been used when a sub-group of a band is meant, and thus considerable confusion has been caused. The next point to be dealt with is the variation in absorption caused by a solvent, a fact that is of material importance in connection with the quantitative relations between the molecular frequencies exhibited by a compound. Hartley was the first to observe the difference in frequency of a particular absorntion band according to whether a substance is examined in the vapour state or in solution in a solvent, and he noted that there is always a small shift towards the red in: passing from vapour to solution. There are, in fact, two different effects of a solvent npon the absorption spectrum of a substance as observed in-the vapour state. One of these has already been mentioned, namely, the appearance of an entirely different absorption band when the substance is dissolved. In this case the vapour exhibits a molecular frequency which is one multiple of the infra-red frequency, whilst the solution exhibits a molecular frequency which is another multiple of that infra-red freauency. In the case of some comnounds it has been shown that bv the nse of different solvents a number of different multiples of the infra-red fundamental are called into play. ON ABSORPTION SPECTRA OF ORGANIC COMPOUNDS. 229 The second effect of a solvent is when the same molecular frequency is common to vapour and solution, but the measurements of this frequency with vapour and solution do not give exactly the same values. 1t is this particular eftect which requires discussion, because unless the phenomenon is understood the relationships between the infra-red fundamental frequency and the visible and ultra-violet frequencies will apparently not hold good. Without going fully into the quantitative measurements it may be stated that the change in the value of the molecular frequency in passing trom vapour to solution depends on the nature of the solvent and on the concentration in that solvent.’° As regards the effect of concentration, the difference between values of the molecular frequency as observed with vapour and solution is greatest with concentrated solutions. As the solution is diluted the value more and more nearly approaches the value for the vapour until at very great dilution the value for the solution equals that for the vapour. This change in the molecular frequency in passing from vapour to solution is not due to the fact that the quantitative relation between visible or ultra-violet bands and the intra-red fundamental does not hold, but to the fact that the infra-red fundamental itself varies slightly in position with the nature of the solvent and the concentration in that solvent. Another important fact to be recorded is that a compound in the liquid state does not show exactly the same molecular frequency as it does in the state of vapour. This, again, is due to a small difference in the infra-red fundamental frequency in the two states. It is obvious, therefore, that in making measure- ments ot molecular frequencies the true values are those obtained with the vapour. If, as frequently happens, measurements cannot be made with the vapour, then very dilute solutions must be used. Above all, in comparing together the various molecular frequencies shown by a given substance it is necessary: that all the measurements be made with the substance under the same conditions. In connection with the effect of solvents on the absorption exerted by a sub- stance, a brief reference may be made to the variation in the absorptive power with concentration. Measurements have as yet only been made for frequencies in the ultra-violet region. At first sight it might be expected that Beer’s law would hold good, namely, that the molecular absorptive power would be independent of the concentration. It is, however, rarely the case that Beer’s law holds good, and in the great majority of cases the absorptive power in- creases with dilution up to a constant) maximum. It has been found that if K isthe maximum absorptive power shown by a substance at very great dilution in a given solvent, and k is the absorptive power at a definite concentration k/K=1—e-4V, where V is the volume in litres containing one gram molecule of the absorbing substance and a is a constant. A more convenient form of the above is log (K / K-k) =aV. The quantitative relationships between the various frequencies shown by a molecule may now be further considered. It has already been stated that the principal frequencies of all the absorption bands shown by a compound in the visible and ultra-violet are always exact multiples of the principal frequency of an important absorption band shown by that substance in the infra-red. This is true of all the absorption bands which are shown by a substance in different solvents, and which Hantzsch attempted to explain by assigning a different formula for each band. Other quantitative relationships have also been discovered, and these may briefly be described, because it has been found possible from a knowledge of them to formulate a quantitative theory which would seem capable of explaining all the observations that have been made on absorption spectra. In the first place it may be noted that the examination of the absorption exerted by a compound in the infra-red reveals the existence of many more bands than the important one which has been called the infra-red fundamental, and’ which determines the frequencies of the visible and ultra-violet bands. , Purther, in every case yet examined the infra-red fundamental lines were in the short wave infra-red region, i.e., between the wave-lengths limits of 8 and 3p. Tf the principal frequencies of all the infra-red bands are examined additional interesting relationships are found. Thus the fundamental infra-red frequency either ig the least common multiple of certain of the long wave infra-red 230 REPORTS ON THE STATE OF SCIENCE.—1920. frequencies or is a multiple of that least common multiple, and indeed this rela- tionship gives the key to the whole of the system of frequencies exhibited by a moiecule. Again, the whole of the principal frequencies.in the infra-red are derived from certain constants, and these constants are characteristic of the elementary atoms of which the absorbing molecules are composed. These con- stants or elementary atomic frequencies lie in the very long wave infra-red region, and the corresponding wave-lengths are of the order of 1000p. The whole of the principal frequencies shown by a molecule are determined as follows: The fundamental infra-red frequency either is the least common multiple of all the elementary atomic frequencies which are active in the mole- cule or is an exact multiple of that least common multiple. The principal frequencies of all the visible or ultra-violet absorption bands shown by that molecule under various conditions are exact multiples of that fundamental infra- red frequency, and therefore are characteristic of that molecule. In addition to all these frequencies which are true molecular frequencies, there also exist frequencies which are the least common multiples of some (not all) of the elementary atomic frequencies, and these are due to specific groups of atoms in the molecule, and are called intra-molecular frequencies. The question might be asked as to how these relationships have been proved within a very high degree of accuracy in view of the fact that measurements of absorption in the infra-red have not reached a high level of accuracy. It has been found that if a molecule exhibit a principal frequency F in the infra- red, visible, or ultra-violet, there will be associated with that frequency sub- sidiary frequencies F+.A, where A stands for either the intra-molecular fre- quencies or the elementary atomic frequencies. Indeed, it is to this cause that the breadth of the absorption bands is due. As the result of this it is possible to arrive at highly accurate determinations of the intra-molecular and ele- mentary atomic frequencies by analysis of the absorption bands, especially those in the ultra-violet where the accuracy of measurement is very high. The most usual arrangement of the subsidiary frequencies within an absorp- tion band is as follows : The band consists of a series of sub-groups symmetrically arranged with respect to the principal sub-group with the greatest absorptive power. These sub-groups each possess a principal line for which the absorptive power is a maximum, and all these principal lines form a series of constant frequency difference.. This frequency difference is an intra-molecular frequency and is characteristic of a specific group of atoms within the molecule. Then, again, each sub-group is exactly similar in structure and consists of two or more series of lines, each with constant frequency difference and symmetrically arranged with respect to the principal line. These constant frequency differences are the elementary atomic frequencies characteristic of the atoms composing the specific group within the molecule, and the least common multiple of these is the intra-molecular frequency characteristic of that group of atoms. Two instances may be given which exemplify very fully these relationships, The complete absorption system of sulphur dioxide has been found to be based on three elementary atomic frequencies.1¢ Of these, two, 819 x 104! and 1:296 x 10!2, are characteristic of the sulphur atom because they also form the basis of the infra-red frequencies of hydrogen sulphide, and the third, | 24531 x 1011, is characteristic of the oxygen atom. Krom direct measurement the two possible intra-molecular frequencies of the water molecule have been found to be 75 x 10! and 1:7301 x 10%. Obviously if 2:4531 x 1011 is characteristic of the oxygen atom it should form one of the fundamental constants of the water molecule. From these three values alone it has been found possible?” to calculate the whole of the structure of the infra-red bands of water, and the values obtained agree absolutely with those observed.1® Again, in one of the ultra-violet bands of naphthalene there exists a constant frequency difference of 1-4136 x 101° between the sub-groups, which is therefore an intra-molecular frequency, and thus must be characteristic of a definite group of atoms within the naphthalene molecule. The two most obvious groups of atoms are the phenyl group and the olefine group, and therefore the frequency 1:4136 x 101% should be the true molecular frequency of either benzene or one of the olefines, the olefines being very similar in their characteristic frequencies. ee ON ABSORPTION SPECTRA OF ORGANIC COMPOUNDS. 231 This was found to be true for the olefines since ethylene shows a series of bands in the short wave infra-red, the principal frequencies of which are exact multiples of 14136 x 101°, In formulating a theory of absorption spectra the following relationships which have been established must be considered.}* 1. Every elementary atom possesses one or more frequencies which are characteristic of the element. 2. When atoms of different elements enter into combination the resulting molecule is endowed with a new frequency which is the least common multiple of the frequencies of the atoms it contains. This is called the true molecular frequency. 3. lhe central frequencies of all absorption bands, that is, those frequencies for which the absorptive power is greatest, are molecular frequencies characteristic of the molecules, since these alone persist when the substance is cooled to low temperatures. 4. The molecular frequencies in the visible and ultra-violet regions are exact multiples of a molecular frequency in the short wave infra-red, which is called the infra-red fundamental frequency. 5. The infra-red fundamental frequency either is the true molecular frequency or is an exact multiple of the true molecular frequency. 6. The breadth of an absorption band as observed at ordinary temperatures is due to the combination of the molecular central frequency with subsidiary frequencies. The first question which arises is the meaning of the characteristic atomic frequencies which are the fundamental constants trom which the whole system of trequencies shown by a molecule is derived. Presumably they are connected with the shift of an electron from one stationary orbit to another, a change which must require a definite amount of energy depending upon the electro- magnetic force field of the atom. Indeed, it would seem that, if a possibility be allowed of the shift of an electron from one stationary orbit to another, it becomes necessary at once to accept the conclusion that a definite and fixed amount of energy is involved in the change. It is proposed, therefore, to start from this assumption, that in any elementary atom it is possible to shift an electron from one stationary orbit to another, that a definite amount of energy is required to effect the change, and that this fixed quantity of energy is connected with the frequency by the relation— Fixed Quantity of Energy Constant = Frequency. This is readily to be understood if the constant involves a function of the time taken in the actual operation, which is the same for every atom and is a universal constant. This elementary quantum of energy involved in the electron shift is without doubt the basis of the whole energy quantum hypothesis as applied to absorption and radiation, for it can be shown that the whole can be built up from the original assumption of the elementary quantum as a specific property of the atom. For the sake of convenience only it will be necessary to make use of a value for the constant, and the most recent value for this, based on Planck’s theory, is 656 x 10°’. Using this value, the elementary quanta already calculated, namely, those of hydrogen, oxygen, and sulphur, lie between 525 x 1076 and 1:65 x 107° erg, corresponding with frequencies between 819 x 101° and 2°54 x 10!?. The difference between this conception and Planck’s theory may be emphasised. Whereas according to the latter the frequency is accepted as a characteristic of the atom and the quantum is the result of discontinuous absorption or emission at that frequency, the present theory assumes the quantum of energy as being due to a specific process taking place in the atom and hence a fundamental characteristic of the atom, and that the frequency exhibited by the atom is established and determined by that process. The present theory, therefore, gives a simple physical basis to the energy quantum, 232, REPORTS ON THE STATE OF SCIENCE.—1920, The first fact to be dealt with is that when two or more atoms unite together the resulting molecule becomes endowed with a new frequency which is the least common multiple of the frequencies characteristic of the atoms. Leaving on one side the cause of the chemical combination, the energy lost in the process may be considered. The simplest possible assumption to make is that in the synthesis of any one molecule each of the component atoms contributes an equal amount of the total energy lost. An elementary atom ex hypothesi can only gain or lose energy in elementary quanta, and, further, can only’ enter into chemical combination if it already contains energy that can be evolved. Let the case be considered of two elementary atoms, the characteristic frequencies of which are 9 x 10° and 1°5 x 10", or in wave numbers (1/A) 3 and 5. The smallest equal amounts of energy that the two atoms can lose are five ele- mentary quanta at the frequency 9 x 101° in the one case, and three elementary quanta at the frequency 1°5 x 10% in the other. These two amounts are each equal to one quantum measured at the frequency 45 x 101", which is the least common multiple of the two atomic frequencies. In this is doubtless to be found the key to the first problem—namely, that the true molecular frequency is the least common multiple of the frequencies of the atoms in the molecule. Further, the gain or loss of energy by a molecule as a whole must be equally shared in by the component atoms. When a molecule absorbs or loses energy as a whole, it must do so by means of the elementary quanta characteristic of its atoms. In the case of the molecule specified above, the smallest amount of energy it can gain or lose as a whole ig the sum of five quanta at the frequency 9 x 10!° and three quanta at the frequency 15 x 10!!. This minimum amount of molecular energy is two quanta at the true molecular frequency, and in this again is to be found an explanation of the fact that the true molecular frequency is the least common multiple of the atomic frequencies. It is evident, therefore, that starting from the conception of the elementary energy quantum required to shift one electron and making the simple assumption that the combining atoms share equally in the energy loss on combination and in the future energy changes of the resulting molecule, we arrive at the con- ception of molecular quanta, and hence molecular frequency, the latter being the least common multiple of the atomic frequencies. It can be shown that, when molecules under normal conditions are dealt with, one of the most important frequencies they possess is the infra-red fundamental frequency, which is an exact multiple of the true molecular frequency. In the case of sulphur dioxide the infra-red fundamental is fourteen times the true molecular frequency, and in the case of water it is eight times the true molecular frequency. It was stated above that the smallest possible equal amounts of energy which two or more atoms can evolve when combining together are equal to one quantum measured at the frequency which is the least common multiple of their atomic frequencies. It does not follow, of course, that the reacting atoms only evolve this smallest possible amount of energy. They may evolve an amount of energy which is 2, 3, 4, &c., times this smallest quantity, with the result that the smallest frequency truly characteristic of the molecule may be a multiple of the true molecular frequency. Indeed, it would seem that the infra-red fundamental is the frequency which is truly characteristic of the freshly synthesised molecule. At the commencement the simplest possible case was considered of the com- bination of two atoms, each characterised by a single elementary quantum. There is no necessity to restrict the conditions in this way, and it is to be expected that, at any rate in the atoms of some elements, there will exist more than one possibility of shift of the electrons, and that there will be elementary quanta of different sizes associated with such atoms. It has already been found that two different elementary quanta are associated with the atom of oxygen in the water molecule and with the atom of sulphur in the molecule of sulphur dioxide. : Whilst the establishment of molecular quanta, and hence of molecular frequency, is a simple deduction from the conception of elementary atomic quanta, it cannot be denied that the molecule may also exhibit those frequencies which are characteristic of its component atoms. Although these atoms have united together to form the molecule, there is no reason to expect that they have ee ¥ Be) eq. ON ABSORPIION SPECTRA OF ORGANIC COMPOUNDS. £83 thereby lost their individuality as far as their powers of absorbing or radiating energy are concerned. ‘he conception of the molecular quantum 1s based on the assumption that the component atoms can gain or lose elementary quanta when in combination. In addition to this, there is definite evidence that the molecule exhibits the specific frequencies of its atoms, since, although these atomic frequencies have not yet been observed in the long-wave infra-red, they are found in combination with the molecular frequencies as subsidiary frequencies within the absorption band groups in the intra-red, visible, and ultra-violet regions. The question then arises as to the course of events when a molecule is exposed to radiation of a frequency that is the same as one of its characteristic atomic frequencies which may be active in the extreme infra-red. Let it be supposed that the molecule formed by the combination of two elementary atoms haying the characteristic frequencies 9 x 10'° and 15 x 101 is exposed to monochromatic radiation of the frequency 9 x 10!°. The atom haying this frequency will absorb this energy in elementary quanta of 9 x 656 x 10% erg: and further, let it be supposed that this atom absorb five such quanta. The total quantity of energy now absorbed is equal to the minimum quantity of energy which that atom evolves when combining with the atom with characteristic frequency 1°5 x 10", and is equal to one molecular quantum at the true molecular frequency. If the postulate made at the beginning as to the combination of atoms be accepted, then it would seem to follow as a natural consequence that the total energy absorbed by the atom can be transferred to or taken over by the whole molecule as exactly one true molecular quantum, In fact the molecule can obtain one true molecular quantum by the absorption of a whole number of elementary quanta by its atoms, the whole number being of course determined by the frequencies of the other atoms in the molecule and the least common multiple of all the atomic frequencies. Further, there is no reason against this process being continuous in the sense that a molecule will be able to gain more true molecular quanta than the single one by absorption of the specified number of elementary quanta by its atoms. Again, this process will be reversible : that is to say, a molecule will be able to radiate one or more true molecular quanta in the form of the specified number of elementary quanta characteristic of one of its atoms. It will be seen that this leads to the conception of critical amounts of energy associated with elementary atoms in combination, the critical amount of energy of an atom being a whole number of elementary quanta characteristic of that atom which in their sum equal one true molecular quantum characteristic of the molecule of which that atom forms a part. When an atom is exposed to radiation of a frequency equal to its own frequency, it can absorb its elementary quanta until its critical quantity is reached, when this critical quantity becomes merged into the molecular energy content as one true molecular quantum. Amongst the quantitative relationships detailed above was mentioned the fact that the central frequencies of all absorption bands, that is to say, all molecular frequencies exhibited by a molecule in the visible and ultra-violet, are exact multiples of the infra-red fundamental. It is therefore evident that one molecular quantum absorbed at one of the molecular frequencies in the visible or ultra-violet is equal to an exact number of quanta at the infra-red funda- mental. If a molecule absorbs one quantum at one of these higher frequencies, this amount of energy can be radiated again as a whole number of quanta at the infra-red fundamental, or partly as quanta at this frequency and partly as elementary atomic quanta. This is the process underlying the phenomena of phosphorescence and fluorescence, and in this particular case the phosphorescence will be in the form of infra-red quanta. Further, it is obvious that the fluorescence emission need not of necessity be evolved as a whole number of molecular quanta at the infra-red fundamental, but may be radiated as one molecular quantum at a molecular frequency which is a multiple of the infra-red fundamental, the remainder being radiated as molecular quanta at the infra-red fundamental or as elementary atomic quanta, For example, if the molecule absorbs one molecular quantum at the frequency which is ten times the infra-red fundamental, this energy may be evolved as one quantum at the frequency which is nine times the infra-red fundamental and one quantum at the infra-red funda- mental itself. In such a case the fluorescence will be in the visible or ultra- 934 REPORTS ON THE STATE OF SCTENCE.—1920. violet region of the spectrum. The factors governing these various alternatives are determined by the conditions under which the molecules exist. It will be seen from this that a molecule can acquire one or more molecular. quanta at the infra-red fundamental in three different ways: by exposure to radiation equal to its atomic frequencies, by exposure to radiation of frequency equal to the infra-red fundamental, or by exposure to radiation of a frequency which is an exact multiple of the infra-red fundamental. The next point to be considered is the structure of the absorption bands, that is to say, the system of subsidiary frequencies which are always found asso- ciated with the true molecular frequency when the absorbing or radiating power of molecules is examined at ordinary temperatures. These subsidiary frequencies have been attributed by Bjerrum *° to the rotation of the molecules and by Kriger?! to their precessional motions. Without discussion in detail it may be pointed out that both these theories break down. In the first place neither theory takes account of the fact that the subsidiary frequencies are due to the atomic frequencies, and in the second place it is necessary for the purpose of these theories to postulate impossibly large variations in the values of the molecular rotation or molecular precession. On the other hand, the conception now put forward of elementary atomic quanta of energy, whereby definite atomic frequencies are established, would seem capable of affording a very simple and straightforward explanation. More- over, this conception leads to the establishment of exact frequencies without any possibility of variation. The case may again be considered of the molecule formed by the combination of the two elementary atoms for which the elementary quanta are 9 X 6:56 x 1077 and 1:°5 x 6°56 x 1016 erg,and which therefore exhibit the characteristic frequencies 9 x 101° and 1:5 x 10! respectively. Hx hypothesi the elementary quantum is associated with the shift of one electron from one. stationary orbit to another, and, of course, there is no reason to assume that only one electron can be so shifted. There may be many such electrons which can be so shifted, the amount of energy being the same for each; and conse- quently it will be possible for one atom to absorb 1, 2, 3, &c., elementary quanta in the same unit of time. The atom will therefore exhibit frequencies which are 1, 2, 3, &c., times its fundamental frequency. The two atoms specified above will in the free state exhibit frequencies of n x 9 x 10!°and n x 1'5 x 10% respectively, where n= 1, 2, 3, &c. The molecule formed by the combination of these two atoms can also exhibit these frequencies, but now the upper limit of n will be fixed by the critical quantity previously defined. Since the least common multiple of the two atomic frequencies is 4°5 x 1011, the upper limits of n for the two atomic frequency series shown by the molecule will be 4 and 2 respectively, since when 7 = 5 and 3, the two atomic frequency series will con- verge in the true molecular frequency. Perhaps, therefore, the true molecular frequency will be better understood as the convergence frequency of the atomic frequency series than as the least common multiple of the atomic frequencies. We may now consider one of the true molecular frequencies. Since the molecule can absorb as a whole one quantum at that frequency, and since also each atom within the molecule can absorb one or more elementary quanta, there is no reason why the two processes should not be simultaneous. The molecule will then absorb in one unit of time an amount of energy equal to the sum of one true molecular quantum and one or more elementary quanta. This will result in the establishment of the subsidiary frequencies M + nA, where M is the true molecular frequency, A is the atomic frequency, and n = 1, 2, 8, &c., the upper limit of n being fixed by the critical value as already explained. Similarly there will be established the subsidiary frequencies M—nA, for the following reason. Let the molecule which is in radiant equilibrium with its surroundings absorb one quantum of energy at one of its atomic frequencies. In order for it to gain a molecular quantum at one of its true molecular frequencies it will now only be necessary for it to absorb the molecular quantum, less the atomic quantum already absorbed. It has already been shown how on the present conception summation of atomic quanta can take place to form molecular quanta ; so it would follow that, after the absorption of a given number of elementary quanta beyond that associated with the radiant equilibrium, the molecule will be able to absorb the balance necessary to form one molecular ON ABSORPTION SPECTRA OF ORGANIC COMPOUNDS. 235 quantum. In other words, the molecule will be endowed with the frequencies M—7nA. Emphasis may be laid on the fact that, under normal conditions, when the molecule is in radiant equilibrium with its surroundings the subsidiary frequencies M+7A are actually observed; and further, that in these series of subsidiary frequencies the maximum observed value of 7 is one Jess than the critical value ; that is to say, the subsidiary frequencies associated with two consecutive values of the molecular frequency do not overlap. Obviously, if the molecule is screened from all external radiation with frequency equal to its atomic frequencies—that is to say, it is cooled to low temperatures—the whole of the above deductions as to subsidiary frequencies fail, and the subsidiary frequencies must therefore vanish. This has been observed, since at very low temperatures only the central molecular frequencies remain. In the foregoing the simplest case only was dealt with of a binary molecule formed by the combination of atoms of two different elements. Exactly the same conditions will, of course, obtain in more complex molecules, but added to these will be new conditions resulting from the existence of groups of atoms within the molecule. For instance, even in the apparently simple case of the water molectile the conditions will be more complex, owing to the undoubted fact that in this molecule the hydroxyl group exists as an integral portion of the molecule. Whilst, of course, the true molecular frequency will be the convergence frequency of all the atomic frequencies, it is the subsidiary fre- quencies that will exhibit a greater complexity. This complexity, however, is only one of degree, and its explanation follows exactly the same principles as were laid down for the simplest possible binary molecules. The specific case of the water molecule may be discussed in which there are three atomic fre- quencies, 1:0635 x 1011, 2:1159 x 1011, and 274531 x 1011. Whilst the true mole- cular frequency of the water molecule is the convergence frequency of these three, 6°1326 x 10!2, we have also to take into account the intra-molecular fre- quency of the OH group. Now in the molecule H—O—H there are two frequencies active for oxygen and one for hydrogen, and thus there are two possible intra-molecular frequencies for the OH group, depending on which oxygen frequency is concerned. In addition, therefore, to the three atomic frequency series the molecule will also show intra-molecular or OH series. Each of these intra-molecular frequencies is the convergence frequency of two atomic series, and will be associated with subsidiary frequencies to form a band group. If I be the intra-molecular frequency, the only subsidiary fre- quencies associated with I will be given by I-+mA, and I+ nAg, where A, and A> are the two atomic frequency series converging at I, and n=1, 2, 3, &c., with an upper limit defined by the critical value. There will also exist two series of frequencies, I, 21: 31,1, &c., and Iz, 212, 312, &c., each associated with its subsidiary frequencies. These intra-molecular frequencies will converge at the true molecular frequency. In the case of the water molecule there are two intra-molecular frequency series, namely 7-5 x 101, which is the convergence frequency of the atomic frequencies, 1:0635 x 101! and 2°1159 x 1011, and 1-7301 x 1012, which is the convergence frequency of the atomic frequencies 21159 x 1011 and 2°4531 x 1011, When the subsidiary frequencies associated with the given true molecular frequency are considered, instead of only the subsidiary frequencies M+7A, there will exist as subsidiary frequencies M+nI-+mA, where n and m=0, 1, 2, &c., each having its own critical limit, I is one or other of the intra-molecular frequencies, and A stands for the two atomic frequencies which have I as their convergence frequency. This will obviously result in the whole group of sub- sidiary frequencies associated with the given molecular frequency being divided into sub-groups. The central sub-group will be given by n = 0, and the central lines of the sub-groups will be given by m = 0. This is exactly the structure that has been observed in the case of water and sulphur dioxide, both of which molecules have three atomic frequencies. Perhaps the most striking experi- mental confirmation is to be found in the fact that in any one sub-group the subsidiary frequencies are formed from only those atomic frequencies which have the intra-molecular frequency as their convergence frequency. None of the previous theories are able to account for this selective association of the atomic frequencies. 236 REPORTS ON THE STATE OF SCIENCE.—1920. With still more complex molecules it becomes necessary to accept the exist- ence of small atomic groupings within the principal groupings. Without going into the resulting system in detail it may be stated that this will result in the sub-division of the sub-groups into smajler sub-groups. It is of considerable interest to note that the phosphorescence and absorption bands shown, by certain uranyl compounds exhibit this type of structure.? Before entering further into the quantitative relationships one point arising from the foregoing discussion of energy quanta may be mentioned. It has been shown that in the water molecule the oxygen atom exhibits two characteristic frequencies and the hydrogen atom one, whilst in sulphur dioxide the oxygen atoms exhibit one and the sulphur atom two characteristic frequencies. It is difficult to avoid the conclusion that the characteristic atomic trequency is the basis of the valency of that atom. Thus a univalent atom may be one for which there is only one possible shift of its electrons, with a bivalent atom there may be two possible shifts, and so on. From this it would also follow that the numerical size of the elementary quantum associated with the atoms of an element determines the position of that element in the series of electro- positivity. Obviously the larger the elementary quantum associated with an atom the greater will be the energy given out when that atom enters into combination. Further, when a multivalent atom enters into successive com- bination with atoms of a given univalent element, its largest elementary quantum will be concerned when it combines with the first atom. ‘I'his will be followed by the next largest, and so on. This will mean that the ‘strength’ of its different valencies will be different, and the individual bonds with the various atoms of the univalent element will require different amounts of energy to resolve them. There now remains to be considered the origin of chemical reaction. The relationships between the frequencies shown by a molecule and its component atoms have been discussed, but nothing has been said as to why atoms combine together and why certain specific properties are associated with the molecules produced. It would seem that the key to this problem is to be found in the electromagnetic force fields of the atoms. It is evident that, according to the modern view of atomic structure, a central positive nucleus with negative electrons in rotation round it, each atom must form the centre of an electro- magnetic field of force. These force fields were first dealt with by Humphreys,?? who showed that they are capable of giving a quantitative explanation of the Zeeman effect and also of the pressure-shitt of spectrum lines. He deduced the fact that two atoms will attract one another when they approach in such a way that the direction of their electronic motions is the same, and will repel one another when their electronic motions are in opposite directions. Each atom therefore possesses two faces, and when one pair of faces comes together they repel one another, and when the other pair comes together they attract one another. In other words, an atom forms the centre of an electromagnetic field of force, the opposite poles of which are localised in two opposite faces of the atom. Let it be supposed that two atoms of different elements are brought together in such a way that their mutually attracting faces come together. They will at once tend to form an addition complex which can lose energy in the manner already described. ‘The two atoms radiate equal amounts of energy as a whole number of elementary quanta whereby the resulting molecule becomes endowed with the frequency based on the least common multiple of the atomic frequencies. This molecule is now rendered a stable entity, and can only be resolved into its atoms by absorbing an amount of energy equal to that lost in its formation. This quantity of energy consists of a definite number of true molecular quanta. As will be noticed, however, in this suggestion, that the reactivity of atoms for one another is due to the attraction of their respective force fields, and that their combination consists in their joint loss of equal amounts of energy, no account has been taken of the other faces of these combining atoms. Whereas the combination of the atoms produces a molecule characterised by a specific energy quantum, it is not possible to consider that the force fields due to the external atomic faces can exist without influence on one another. These external force lines must condense to form an external molecular force field, and ON ABSORPTION SPECTRA OF ORGANIC COMPOUNDS. 937 in this process energy must be evolved. It was not possible previously to deter- mine the amount of energy lost by each molecule in this process, but the theory of elementary and molecular quanta put forward now enables this to be done with accuracy. It was shown above that a freshly synthesised molecule is characterised by a definite molecular quantum, and hence by a specified frequency in the short wave infra-red, which has been called the infra-red fundamental frequency. When a freshly synthesised molecule loses energy as a whole it must do so in quanta at the infra-red fundamental, and thus it would follow that, when the external force fields of the component atoms of a freshly syn- thesised molecule condense together to form ‘the molecular force field, the system loses energy in quanta at the infra-red fundamental of that molecule. Clearly, the molecule itself will not suffer any Joss of individuality as far as its characteristic frequencies are concerned. None of the deductions from the conception of elementary and molecular quanta made above will be contra- dicted, and the only change accompanying the formation of the molecular force field will be the endowment of the system with an additional molecular frequency which is an exact multiple of the infra-red fundamental. Let it be supposed that in the formation of its molecular force field a given molecule loses one molecular quantum at the infra-red fundamental. If the freshly synthesised molecule were allowed to absorb one quantum at the infra-red fundamental it would become endowed with certain properties. If now it is required to bring the molecule with its molecular force field established by the loss of one quantum into this physical state it will be necessary to supply it with energy equal to two energy quanta at the infra-red fundamental. There can be no reason against the molecule and its force field absorbing both these quanta simultaneously. and therefore it may be concluded that the system of molecule and force field becomes endowed with a new and additional frequency which is exactly twice the infra-red fundamental. Similarly, it follows that, if the force-field con- densation proceeds to the extent defined by the loss of tao molecular quanta at the infra-red fundamental, the molecule and its force field will be endowed with a new and additional frequency which is exactly three times the infra-red fundamental. Generally, if the infra-red fundamental of a freshly synthesised molecule be denoted by M, and if in the formation of the force field 2 quanta are evolved at that frequency. the system will be characterised by two molecular frequencies, namely M and M(x+1). Since the external atomic fields are bound to undergo a certain amount of condensation, it is evident that the molecule must exist in one of a number of possible phases, each molecular phase being defined by the number of molecular quanta lost in the force-field condensation and characterised by a specific frequency which is an exact multiple of the infra-red fundamental. The initial assumption was made that the chemical reactivity of atoms is due to the attraction exerted by their electromagnetic fields. As the result of this attraction the atoms form an addition complex which constitutes the first stage in the reaction between them, the second stage being the joint loss of equal amounts of energy by all the atoms whereby the freshly synthesised molecule is formed with its infra-red fundamental. Similarly the reactivity of molecules will be a function of their force fields, and the first stage of any reaction between two or more molecules will be the formation of the addition complex due to the attraction between their respective force fields. It follows, therefore, that the reactivity of a molecule will depend on the molecular phase in which it exists, and, further, the creater the extent to which the condensation in the molecular force field has taken place the smaller will be the reactivity. The phase in which a molecule exists is governed by the nature of the external force fields of its atoms. The more equally balanced these are the greater will be the condensation that takes place between them. The particular phase assumed by a molecule will depend on the external conditions, such as temperature, nature of solvent, &c. The experimental evidence in favour of the existence of these molecular phases is exceedingly strong. It is not possible to give here a detailed account of this evidence, but two or three of the most striking observations may be mentioned. For instance, it is common knowledge that substances which pos- sess very small reactivity are characterised by molecular frequencies which are 238 FEPORTS ON THE STATE OF SCIENCE.—1920. large multiples of their infra-red fundamentals and lie in the extreme ultra- violet. The converse of this is also true that substances with measurable reactivity are characterised by frequencies which relatively are smaller multiples of the infra-red fundamental. Again, it is possible by changing the external conditions of temperature or solvent to change the molecular frequency ex- hibited by a given substance, and in some cases as many as six different mole- cular frequencies have been brought into play, each of which is an exact multiple of the infra-red fundamental of that substance. This means that six different molecular phases of the same compound have been observed. Then, again, it has been proved that a particular frequency is associated with a specific chemical reactivity, or, in other words, a particular molecular phase is endowed with its own reactivity. An interesting point arises at once when the force fields of free elementary atoms are considered. It has been assumed that in a molecular force field the force lines due to the external faces of its atoms undergo condensation to form a condensed molecular force field. It is manifest if an atom consist of a central positive nucleus with a single plane ring of electrons that the force lines at the two faces of that atom will be exactly equal and opposite, that condensation must occur to form an atomic field of force, and that this con- densation will be very great with the evolution of a large number of atomic quanta. Such an atom will under ordinary circumstances possess little or no power of attracting other atoms, and hence will have no measurable chemical reactivity. It is possible that the atoms of the inactive gases, helium, neon, &e., are of this type. On the other hand, if there exist more than one plane orbit of electrons, a condition of asymmetry will be set up in the atomic force field, with the result that the complete condensation to form a non-reactive atomic field is no longer possible. It does not seem improbable that in the various types of asymmetry likely to exist the explanation is to be found of the various properties of elementary molecules which are familiar to the chemist. _ The extreme conditions resulting from this asymmetry would be (1) the non- reactive diatomic molecule such as H,, N,, &c.: (2) the highly reactive mon- atomic molecule such as Na, K, &c.; (3) the highly reactive diatomic molecule such as F',; (4) the non-reactive polyatomic molecule such as those of carbon. Apart from this possibility, which need not now be discussed, it is necessary to take into account the fact that at any rate in the case of elementary molecules containing more than two atoms the different molecular phases may be capable of separate existence. Smits has put forward the theory that the different allotropic modifications of an element are equilibrium mixtures of different molecular species of that element. Thus the various allotropic modifications of sulphur are equilibrium mixtures of some or all of four molecular species of sulphur known as §,, §,, S,, and §,. There seems little doubt that what Smits calls molecular species are in reality four different molecular _ phases of sulphur, which differ in their energy content by a definite number of quanta at the infra-red fundamental of sulphur. It is of considerable interest to note that each of the four varieties of the sulphur molecule exhibits a different molecular frequency in the visible or ultra-violet region, and that thev therefore conform to the definition of molecular phases. _ The molecular phase hypothesis throws a considerable light on the mechanism of chemical reaction, and enables accurate calculations to be made of the com- plete energy changes which are involved in any reaction. In the first place, the calculation may be made of the total energy which is evolved during the combination of elementary atoms to form molecules which are in radiant equilibrium with their surroundings. Let the case be considered of the combination of atoms of different elements, and further let the characteristic frequencies of these atoms be 910°, 1:°2x 1011, 15 x 1011, and 2°1 x 101! respectivelv. The least common multiple of these four frequencies is 1:26 x 1013, and this therefore will be the true molecular frequency of the resulting molecule. On the assumption made in the preceding paper that an equal amount of energy is contributed for each atomic frequency, the smallest equal amount evolved for each atomic.frequency is 1:26 x 6:56 ~ 1114 or 82656 x 1074 ergs. The total quantity of. energy evolved therefore in the actual formation of each molecule will be 4 x 82656 x 10°!4 or 330624 x 1075 ergs, ON ABSORPTION SPECTRA OF ORGANIC COMPOUNDS. 939 which will result in the establishment of the infra-red fundamental 5°04 x 10%. Since one quantum at this frequency equals the sum total of energy evolved, the absorption of one energy quantum at this frequency will result in the molecule just being resolved back again into its atoms, The next stage in the process will be the formation of the molecular force field, and let this be accompanied by the loss of 20 quanta at the infra-red fundamental 5:04 x 1015. As shown above, the molecular system will now be endowed with an additional characteristic frequency, 5-04 x 21 x 10 or 1:0584 x 101°, which lies in the ultra-violet region of the spectrum. The energy lost by each molecule during the condensation of its force field will be 504 x 20 x 656 x 1074 or 661248 x 107% ergs. The total energy therefore evolved in the two processes is the sum of 330624 x 10° ergs evolved in the com- bination of the atoms and 6:61248 x 101? ergs evolved during the condensation to form the molecular force field, which amounts to 6943104 x 107? ergs. This amount of energy, however, is equal to one quantum at the frequency 1:0584 x 1015, which is characteristic of the molecular phase. As this is obvi- ously true whatever may have been the number of quanta at the infra-red fundamental lost during the formation of the molecular force field, the general conclusion is reached that one energy quantum measured at the largest fre- quency characteristic of the molecule is just sufficient to resolve that molecule into its atoms. This is a general conclusion which includes Einstein’s photo- chemical law. The values taken above of atomic frequencies,* infra-red fundamental, and molecular phase frequency closely approximate to those observed with many compounds. It will be seen that the amount of energy evolved in the com- plete process may be very large, and for a gram-molecule amounts in the above instance to about 102,320 calories. It must, of course, be remembered that in any reaction the observed heat evolved is less than the total amount evolved in the formation of the molecular systems of the products by the amount necessary to resolve the initial substance or substances into atoms. An important deduction from this molecular phase theory may be made as regards the energy changes involved in chemical reaction. It is obvious that in any reaction in which the first stage is the resolution of the molecule into its atoms the energy necessary for this first stage can at once be found from the frequency of the phase in which that molecule exists. | Unfortunately, there does not seem to be known at present a single instance of a simple reaction in which the molecular phase frequencies have been accurately measured, both for the original substance and the products, and consequently it is not possible at the present time accurately to calculate the net change of energy observed in any reaction. On the other hand, in the vast majority of chemical reactions the reacting molecules are not resolved into their atoms in the first stage of the process. It has been shown in a number of cases that it is only necessary to bring the molecules into a particular phase in order to enable them to enter into the desired reaction. A very typical example of the difference in reactivity shown by the different molecular phases of the same molecule is afforded by benzaldehyde. In alcoholic solution this substance ex- hibits two molecular frequencies in the ultra-violet, and therefore two mole- cular phases co-exist. It is well known that in alcoholic solution benzaldehyde is readily oxidised by gaseous oxygen to benzoic acid, and that it is not con. verted to benzaldehydesulphonic acid when sulphuric acid ig added to the % In the example given simple numbers have been used for the atomic fre- quencies in order to avoid complexity in calculation. It is perhaps worth while to point out here that there are certain indications that the fundamental frequencies of the atoms of different elements are possibly connected by simple arithmetical relations. A sufficient number of these atomic frequencies has not yet been computed, owing to the dearth of accurate measurements of the subsidiary frequencies of simple molecules, to justify any conclusions being made. It is of some interest, however, to note that in sulphur dioxide the oxygen frequency 2-4531 x 10! is almost exactly three times the sulphur frequency 8:19 x 10!°. and that in the case of the water molecule the atomic frequency 2°1159 x 101! is very nearly twice the atomic frequency 1:0635 x 1011, - 940 REPORTS ON THE STATE OF SCIENCE.—1920. solution. The reaction with oxygen, therefore, is characteristic of one or both of the two molecular phases present in alcoholic solution. If benzaldehyde is dissolved in concentrated sulphuric acid it exhibits two new molecular fre- quencies, one in the visible and the other in the ultra-violet region. T:wo further molecular phases, therefore, exist in solution in sulphuric acid. In this case the benzaldehyde is no longer oxidised by oxygen, but is readily converted to the sulphonic acid. Now the question arises as to the amount of energy necessary to convert one molecular phase into another and the mechanism whereby this energy is supplied. ‘The amount of energy required per molecule is readily calculated, and is equal to one or more quanta measured at the infra-red fundamental of that molecule. If the frequency characteristic of the first phase is « times the infra-red fundamental and the required phase is characterised by a frequency which is 7 times the infra-red fundamental, then the energy required for each molecule is x—y quanta at the infra-red fundamental. Obviously the molecular system can absorb this energy when exposed to radiation of a frequency equal to its infra-red fundamental, or, as explained above, it may absorb it at any of the frequencies characteristic of its component atoms. Lastly, the molecule mav absorb one quantum at its characteristic phase frequency, and under ordinary circumstances this energy will again be entirely radiated as quanta at a lower phase frequency, the infra-red fundamental, or the atomic frequencies. If there is present a substance capable of reacting with a less condensed phase. then the molecule is converted into that phase and reacts, the balance of energy being evolved as infra-red radiation. The essential point is that the necessary amount of energy to change the molecular phase is x—y quanta at the infra-red fundamental, and that when one quantum is absorbed at the phase frequency the excess energy over and above that required is radiated. The change of molecules from one phase to another under the influence of light is readily enough shown experimentally, but it is necessary to stabilise the second phase in some way, since otherwise it returns instantaneously to the first phase. An interesting example is furnished by trinitrobenzene. an alcoholic solution of which contains a molecular phase characterised by a frequency in the ultra- violet. A piperidine solution contains a molecular phase of trinitrobenzene which is characterised by a frequency in the blue and the solution is deep red in colour. This second phase, therefore, is favoured by piperidine. Tf to an alcoholic solution of trinitrobenzene a small quantity of piperidine is added, not more than one molecule of piperidine to 10 molecules of trinitrobenzene, the solution remains perfectly colourless. On exposure to light of the frequency characteristic of the phase in alcohol the solution turns red, owing to the formation of the second molecular phase, and the solution slowly becomes colourless again when placed in the dark. There is no need to enter into a discussion of the application in detail of this theory to the quantitative relations involved in the energy changes of chemical reaction. It is obvious that the theory renders possible the calcula- tion of the complete energy changes, and this aspect of the phenomena may be left. on one side. From the point of view of absorption spectra the essential fact is that the theory leads to the conclusion that a molecule must exist in one of a number of possible phases, each of which is characterised by its own absorption band in the visible or ultra-violet region of the spectrum. It has been proved that a molecule can be brought from one phase to another by the gain of a whole number of fundamental infra-red quanta and that this can be brought about by exposure to radiant energy at a frequency characteristic of the molecule. Reference has already been made to the fact that it is possible to change the nhase in which a molecule exists by the use of a suitable. solvent, and indeed it is to this effect of a solvent that the variation in the absorption spectra of many compounds is due. In order to understand this effect of a solvent. it is necessary to consider the condensation of the molecular force fields a little more in detail. From what has already been said it is clear that this condensation will proceed to the farthest possible extent. In the case of a molecule in which the external force fields of the atoms are well balanced the condensation will proceed far with the establishment of a highly eondensed field characterised by an absorption hand in the extreme ultra-violet. On the other hand, if the external force fields ON ABSORPTION SPECTRA OF ORGANIC COMPOUNDS. 241 are not balanced the condensation will not be so great, and a balance of force lines of one type will remain uncompensated. If this balance be removed in some way then there will be nothing to prevent the condensation from proceed- ing further with the escape of more fundamental infra-red quanta and the formation of a more highly condensed phase. It may be noted in passing that an uncompensated balance of force lines remaining after the condensation of the force field has take place is in all probability the origin of what is known to chemists as residual affinity. Let the case be considered of a molecule which possesses residual affinity of an acid type, and let this molecule be brought into the neighbourhood of another molecule which possesses a force field basic in type. The two will together form a complex, and since the residual affinity of the first is now compensated there is no reason why its force field should not undergo further condensation with the evolution of one or more funda- mental infra-red quanta. Provided that the fundamental infra-red frequencies of the two molecules are similar, these quanta may be absorbed by the second molecule, which is thereby converted into a Jess condensed phase. The similarity of the infra-red fundamental frequencies necessary for this trans- ference of energy quanta is very probable. because, in the first place, observa- tion shows that the fundamental infra-red frequencies of at any rate organic compounds are very near together. In the second place, it has been found that when two substances with not very different fundamental infra-red fre- quencies form a complex, this complex becomes endowed with a new funda- mental infra-red. frequency of its own which lies between those of its com- ponents. This is of material importance, not only because it shows that the complex is a definite entity, but also because the mechanism for transference of fundamental infra-red quanta from one component to the other is perfect. Tt, would seem that in this process is to be found the explanation of the change of phase which frequently takes place when organic compounds pass into solution. It is not possible to avoid mentioning the bearing of this upon the whole problem of catalysis. It has already been stated that each phase of a given molecule is endowed with its own reactivity, and that in order to cause a molecule to enter into a specific reaction it is necessary to bring it into the proper phase. This. change of phase may be produced by the action of light, in which case the reaction is called a nhotochemical one. On the other hand. the change in phace may be produced by a material substance which is called a catalyst. The substance is a catalyst because it increases the velocity of the particular reaction. owing to the fact that it brings more molecules into the reactive nhase than would otherwise exist in that phase. Not the least interesting anvlication of the nresent theory is to the phenomenon of catalvsis, a phenomenon which has not hitherto found a completely satisfactory explanation. After what has been stated of the existence of molecular phases, each with its own characteristic frequency in the visible or ultra-violet. a frequency which is an exact multiple of the infra-red fundamental, it is perhaps scarcelv necessary to discuss many of the observations of the absorption snectra of organic compounds, since the application of the theorv is obvious. Tn order to illustrate this avplication, however, some of the observations recorded in the earlier nages of this report may he considered, and the case of ethyl aceto- acetate and its derivatives may be selected first. Jt was shown quite clearly that neither the oricinal theory of tautomeric equilibrium nor the Hantzsch six-membered ‘ring’ formula can exnlain the absorvtion band shown by the sodium salt. The absorption band-is due to the fact that the substance in the presence of a basic solvent is changed into a phase the characteristic absorption band of which lies in the ultra-violet region. This alteration of phase is ‘characteristic of the ketonic form. since the disubstituted compound. ethyl dimethvlacetoacetate, shows the same band when dissolved in a basic solvent. ' It is noteworthv that exactly the same bands are shown when these compounds are dissolved in piperidine. The reason why the two derivatives, ethyl B-ethoxycrotonate and ethvl dimethylacetoacetate, show only general ahsorption in alcoholic solution is because they exist in a phase the characteristic band of which lies in the extreme 1920 » 242 ' REPORTS ON THE STATE OF SCIENCE.—1920. ultra-violet region beyond that reached with a quartz spectrograph working in air. Lastly, the incipient or very shallow absorption band shown by ethyl B-ethoxycrotonate in the . presence of acid 1s due to the fact that relatively few molecules are brought into a less condensed! phase. by the action of the ak must be clearly understood that the statement that a compound only shows general absorption is very misleading, because it only means that no absorption band is exhibited by that compound between the spectral limits of 7000 and 2100 Angstréms. Such substances will certainly be found to exhibit selective absorption when investigations are made in the very extreme ultra- violet. There is a very fertile field of research in this direction by the use of a vacuum spectrograph with a fluorite prism or a grating, in order to obviate the absorption due to air and quartz. Some preliminary investigations have already been made by Stark, who found evidences of selective absorption in this region by some of the so-called diactinic substances. . Again, the explanation of the results recorded in the examination of the aromatic aminoaldehydes and aminoketones is very simple. These compounds show one absorption band. in alcoholic solution, a second in the presence of a trace of acid, and a third in the presence of a great mass of acid, the frequency of the second being the smallest and that of the third being the greatest. The molecules exist in three different phases under the three conditions.. Similarly the variety of absorption bands which Hantzsch found certain substances to exhibit in different solvents is due to a variety of phases of the same molecule. Thus diphenylyioluric acid can be brought into several different phases by alkali according to the chemical strength of LiOH, NaOH, KOH, RbOH, CsOH. Further, a considerable variety of phases of trinitrobenzene, picric acid and its ether trinitroanisole, can be produced by the use of solvents of different basicity, such as water, alcohol, pyridine, piperidine, dimethylaniline, and alcoholic sodium ethoxide.24 The case of trinitrobenzene and also of trinitro- toluene is interesting, for it is possible with these two compounds not. only to obtain them in highly coloured molecular phases by solution in_ basic solvents, but also to prepare these phases in the pure state. The coloured liquid phase of trinitrotoluene is well known to those engaged in the manu facture of this compound. The corresponding phase of trinitrobenzene can be obtained by dissolving the compound in piperidine. On pouring this solution into excess af hydrochloric acid the trinitrobenzene is precipitated as a red solid, and after drying the colourless form may be dissolved in ether or benzene, leaving the red form. A solution of this in alcohol shows the same absorption band as does the piperidine solution of trinitrobenzene. There indeed is little doubt that the existence of a compound in two or more forms, as is frequently the case in organic chemistry, means the isolation of two or more different molecular phases of the same compound. One of the most interesting cases of the preparation of a molecular phase less condensed than the ordinary phase is the so-called aci-ethers of the nitrophenols.2> These com- pounds on the basis of the quinonoid theory were considered to have the quinonoid formula typified by OCH, O= ont \ (0) put the only evidence on which this formula was based was the instability of the compounds and their visible colour. They are extraordinarily unstable and change at once under the influence of certain solvents into the normal forms. ‘In the light of present-day knowledge there is not the slightest doubt that they are simply less condensed phases of the nitrophenol ethers, having the usually -aecénted formule. ‘Reference was made previously to the quinonoid explanation of the highly coloured hydrochloride of dimethylaminoazobenzene. This again is another ‘example of the conversion of a weak base into a less condensed phase by: the -addition’ of acid ‘such as occurs with the aminoaldehydes and aminoketones. It was ‘pointed out ‘above that the quinonoid explanation fails because a similar ON ABSORPTION SPECTRA OF ORGANIC COMPOUNDS. 248; change in absorption takes place with benzeneazophenyltrimethylammonium: iodide in the presence of acid, although the change is less obvious to the eye.” The most serious criticism of the quinonoid explanation is to be found in the fact that in concentrated acid the colour is not so intense as in dilute acid, for it hardly seems scientific to state that a particular configuration is favoured by acid and then to have to agree to a change from that configuration to another: when more acid is added. Here again as with the aminoaldehydes three molecular: phases exist, one in alcohol, one in dilute acid, and one in strong acid, the primary structure of the molecule being the same in all three. A very: analogous case is pararosaniline, which with one equivalent of acid gives a very marked colour, but in the presence of excess of acid the colour and absorption are different. Three phases again are formed, one in alcohol, one in dilute acid, and one in concentrated acid. poe In all probability the above instances are sufficient to indicate the application of the theory of molecular phases to absorption spectra. In conclusion it may be claimed for the theory that it attempts to co-ordinate on a definite physical basis all absorption spectra observations over the whole spectrum between the extreme limits of wave-length 1000u and O‘lu, and that these attempts seem to meet with considerable success. References. - Hartley, Dobbie, and Lauder, ‘ Trans.,’ 81, 929 (1902). . Hartley and Dobbie, ‘ Trans.,’ 75, 640 (1899). . Hartley, Dobbie, and Paliatseas, ‘ Trans.,’ 77, 839 (1900). . Baly and Desch, ‘ Trans.,’ 85, 1029 (1904) ; 87, 766 (1905). . Baly and Collie, ‘ Trans.,’ 87, 1332 (1905). Baly and Stewart, ‘ Trans.,’ 89, 502 (1906). . Baly, Marsden, and Stewart, ‘ Trans.,’ 89, 966 (1906). . Lowry and Desch, ‘ Trans.,’ 95, 807 (1909). F ate ‘Ber.,’ 43, 3049 (1910); 44, 1771 (1911); 45, 559 (1912); 48, 772 1915). . Hantzsch and Colleagues, ‘ Ann.,’ 384, 135 (1911); Ber., 41, 1204 (1908); 42, 68, 889, 1216, 2119, 2129 (1909) ; 43, 45, 68, 106, 1651, 1662, 1685, 2129, 2512, 3049 (1910); 44, 1771, 1783 (1911); 45, 85, 553, 559, 3011 (1912); 46, 1537, 3570 (1913); 48, 158, 167, 772, 797, 1407 (1915); 49, 213, 226, 511 (1916); 50, 1413, 1422 (1917); 52, 493, 509, 1535, 1544 (1919); ‘ Zeit. phys. Chem., 84, 321; 86,624 (1913). 11. Purvis, ‘Trans.,’ 97, 692 (1910) ; Baly and Tryhorn, ‘Phil. Mag.,’ 31, 417 (1916). 12. Baly and Marsden, ‘ Trans.,’ 98, 2108 (1908). 13. Baly and Rice, ‘ Trans.,’ 101, 1475 (1912). 14. Baly, ‘ Phil. Mag.,’ 2, 632 (1914); ‘ Astrophys. J.,’ 742, 4 (1915). 15. Baly and Tryhorn, ‘ Phil. Mag.,’ 31, 417 (1916). 16. Garrett, ‘ Phil. Mag.,’ 31, 505 (1916) ; Baly and Garrett, ibid., 31, 512 (1916). 17. Baly, ‘ Phil. Mag.,’ 39, 565 (1920). 18. Sleator, ‘ Astrophys. J.,’ 48, 125 (1918). 19. Baly, ‘ Phil. Mag.,’ 40, 1, 15 (1920). 20. Bjerrum, ‘ Nernst Festschrift,’ page 90 (1912). 21. Kriiger, ‘ Ann. der Phys.,’ 50, 346; 51, 450 (1916). 22. Nichols and Merritt, ‘ Phys. Rev.,’ 6, 630 (1915); 9, 113 (1917). 23. Humphreys, ‘ Astrophys. J.,’ 33, 233 (1906). 24. Baly and Rice, ‘ Trans.,’ 103, 2085 (1913). 25. Hantzsch and Gorke, ‘ Ber.,’ 39, 1073 (1906). 26. Baly and Hampson, ‘ Trans.,’ 107, 248 (1915), OMOAIRD A PWr = — i—) R 2 944 REPORTS ON THE STATE OF SCIENCE.—1920. Appendix. List or SUBSTANCES OF WHICH THE ABSORPTION SPECTRA HAVE BEEN EXAMINED IN THE ULTRA-VIOLET AND VISIBLE REGIONS SINCE THE PUBLICATION OF THE LAST Report rm 1916. A Acetic acid and salts. Hantzsch. ‘ Ber.,’ 50, 1422 (1917). Acetone. Lifschitz. ‘ Zeit. wiss. Phot.,’ 16, 140 (1916). Acetylenedicarboxylic acid. Macbeth and Stewart. ‘ Trans.,’ 111,829 (1917). Alizarin. Meek. ‘ Trans.,’ 111, 969 (1917). Alizarin-blue. Meek. ‘ Trans.,’ 111, 969 (1917). Alizarin-Bordeaux. Meek. ‘Trans.,’ 111, 969 (1917). Alizarin-cyanine. Meek. ‘Trans.,’ 111, 969 (1917). Aminoazobenzene. Ghosh and Watson. ‘ Trans.,’ 111, 815 (1917). Anthragallol. Meek. ‘ Trans.,’ 111, 969 (1917). -Aurin. Ghosh and Watson. ‘ Trans.,’ 111, 815 (1917). B Behenolic acid. Macbeth and Stewart. ‘Trans.,’ 111, 829 (1917). Benzeneazoanthranol. Sircar. ‘Trans.,’ 109, 757 (1916). Benzene-l-azo-4-anthrol. Sircar. ‘ Trans.,’ 109,757 (1916). Benzeneazocatechol. Ghosh and Watson. ‘ Trans.,’ 111, 815 (1917). Benzeneazo-1.5-dihydroxynaphthalene. Ghosh and Watson. ‘Trans.,’ 111, 815 (1917). Benzene-l-azo-4-naphthol. Sircar. ‘Trans.,’ 109, 757 (1916). Benzeneazo-a-naphthol. Ghosh and Watson. ‘Trans.,’ 111, 815 (1917). Benzeneazo-8-naphthol. Ghosh and Watson. ‘Trans.,’ 111, 815 (1917). Benzeneazo-8-naphthylamine. Ghosh and Watson, ‘'Trans.,’ 111, 815 (1917). Benzeneazophenol. Ghosh and Watson. ‘Trans.,’ 111, 815 (1917), Sircar. ‘ Trans.,’ 109, 757 (1916). Benzeneazopyrogallol. Ghosh and Watson. ‘ Trans.,’ 111, 815 (1917). Benzeneazoquinol. Ghosh and Watson. . ‘ Trans.,’ 111, 815 (1917). Benzeneazoresorcinol. Ghoshand Watson. ‘ Trans.,’ 111, 815 (1917). Benzene- 1-azo-1'.2'.3'.4'-tetrahydro-4-naphthol. Sircar. ‘ Trans.,’ 109, 757 (1916). Benzoic acid. Ley. ‘ Zeit. wiss. Phot.,’ 18, 178 (1918). p-Bromobenzene-1l-azo-4-anthrol. Sirear. ‘ Trans.,’ 109, 757 (1916). p-Bromobenzene-]-azo-4-naphthol. Sircar. ‘ Trans.,’ 109, 757 (1916). p- Bromobenzeneazophenol, Sirear. ‘ Trans.,’ 109,757 (1916). p-Bromobenzene- l-azo-1’.2'.3'.4'-tetrahydro-4-naphthol. Sirear. ‘ Trans.,’ 109, 757 (1916). Bromodinitrotriphenylmethane. Hantzsch and Hein. ‘ Ber.,’ 52, 493 (1919). C Chloranil. Lifschitz. ‘ Ber.,’ 49, 2050 (1916). Chrysoidine. Ghosh and Watson. ‘ Trans.,’ 111, 815 (1917). Cinnamic acid. Ley. ‘ Ber.,’ 51, 1808 (1918). Py » Ley. ‘ Zeit. wiss. Phot.,’ 18, 178 (1918). a + Macbeth and Stewart. * Trans.,’ 111, 829 (1917). 65 Stobbe. ‘ Ber.,’ 52, 1021 (1919). Cinnamylideneacetic acid. Macbeth and Stewart. ‘Trans.,’ 111, 829 (1917). Cobalt acetate. Ley and Ficken. ‘ Ber.,’ 50, 1123 (1917). Cobalt picolate. Ley and Ficken. ‘ Ber.,’ 50, 1123 (1917). Crystal violet. Hantzsch. ‘ Ber.,’ 52, 509 (1919). “9 a Kehrmann and Sandoz. ‘ Ber.,’ 51, 915 (1918). ef SS derivatives. Kehrmann and Sandoz. ‘ Ber.,’ 51, 915 (1918). nitrile of. Lifschitz. ‘ Ber.,’ 52, 1919 (1919). a and Cyanopyronin Dye-stuffs. Kehrmann and Sandoz. ‘Ber.,’ 53, 63 (1920 ON ABSORPTION SPECTRA OF ORGANIC COMPOUNDS. 245 D 4.4’-Diaminoazobenzene. Ghosh and Watson. ‘ Trans.,’ 111, 815 (1917). Dibenzyl. Ley. ‘ Zeit. wiss. Phot.,’ 18, 178 (1918). Diethylthiazin bromide. Kehrmann. ‘ Ber.,’ 49, 2831 (1916). 1.4-Dihydroxyanthraquinone. Meek. ‘ Trans.,’ 111, 969 (1917). 3.4-Dihydroxymalachite-green. Ghosh and Watson. ‘ Trans.,’ 111, 815 (1917). Diiodoacetylene. Macbeth and Stewart. ‘ Trans.,’ 111, 829 (1917). Diiodoethylene. Macbeth and Stewart. ‘ Trans.,’ 111, 829 (1917). p-p'-Dimethoxyfuchsonedimethylimonium chloride. Hantzsch. ‘Ber.,’ 52, 509 (1916). Dimethyl sulphide. Hantzsch. ‘ Ber.,’ 52, 1544 (1919). Dimethylaminoazobenzene. Hantzsch. ‘ Ber.,’ 52, 509 (1919). Dimethylaniline. Ley. ‘ Zeit. wiss. Phot.,’ 18, 178 (1918). Dimethyldiacetylene. Macbeth and Stewart. ‘ Trans.,’ 111, 829 (1917). Dimethylpyrone. Hantzsch. ‘ Ber.,’ 52, 1535 (1919). Dimethylthiazin perchlorate. Kehrmann. ‘ Ber.,’ 49, 2831 (1916). Dimethyl-o-toluidine. Ley. ‘Zeit. wiss. Phot.,’ 18, 178 (1918). 4.5-Dinitro-3-acetylaminoveratrole. Gibson, Simonsen, and Rau. ‘ Trans.,’ 111, 69 (1917). 5.6-Dinitro-3-acetylaminoveratrole. Gibson, Simonsen, and Rau. ‘ Trans.,’ 111, 69 (1917). p.'p-Dinitrodiazoaminobenzene. Hantzsch and Hein. ‘ Ber.,’ 52, 493 (1919). p-p'-Dinitrodiphenylamine. Hantzsch and Hein. ‘ Ber.,’ 52, 493 (1919). s-Diphenylethane. Macbeth and Stewart. ‘ Trans.,’ 111, 829 (1917). Di-cyclo-pentadiene. Stobbe and Diinnhaupt. ‘ Ber.,’ 52, 1436 (1919). Dithioindigo. Lifschitz and Lourié. ‘ Ber.,’ 50, 897 (1917). Doebner's violet and derivatives. Kehrmann and Sandoz. ‘ Ber.,’ 51, 915 (1918). E Elaidic acid. Macbeth and Stewart. ‘ Trans.,’ 111, 829 (1917). Eosine. Miethe and Stenger. ‘ Zeit. wiss. Phot.,’ 19, 57 (1920). Erucic acid. Macbeth and Stewart. ‘ Trans.,’ 111, 829 (1917). B-Ethoxycinnamic acid. Ley. ‘ Ber.,’ 51, 1808 (1918). a-Ethoxystyrol. Ley. ‘ Ber.,’ 51, 1808 (1918). 8-Ethoxystyrol. Ley. ‘ Ber.,’ 51, 1808 (1918). Ethyl benzoylaretate. Ley. ‘ Ber.,’ 51, 1808 (1918). Ethyl dinitrophenylmalonate. Hantzsch and Hein. ‘Ber.,’ 52, 493 (1919). Ethyl nitrate. Schaefer. ‘ Zeit. wiss. Phot.,’ 17, 193 (1918). Ethyl ortho-formate. Hantzsch. ‘ Ber.,’ 50, 1422 (1917). ” a9 » salts. Hantzsch. ‘ Ber.,’ 50, 1422 (1917). Ethyl phenylpropiolate. Macbeth and Stewart. ‘ Trans.,’ 111, 829 (1917). Ethyl trinitrophenylmalonate. Hantzsch and Hein. ‘ Ber.,’ 52, 493 (1919). Ethylbenzene. Macbeth and Stewart. ‘ Trans.,’ 111, 829 (1917). Ethylene iodide. Macbeth and Stewart. ‘Trans.,’ 111, 829 (1917). FE Filter yellow. Miethe and Stenger. ‘ Zeit. wiss. Phot.,’ 19, 57 (1920). Fluorescein. Miethe and Stenger. ‘ Zeit. wiss. Phot.,’ 19, 57 (1920). Formic acid and salts. Hantzsch. ‘ Ber.,’ 50, 1422 (1917). Fuchsine. Hantzsch. ‘ Ber.,’ 52, 509 (1919). Fuchsonedimethylimonium chloride. Hantzsch. ‘ Ber.,’ 52, 509 (1919). Fumaric acid. Macbeth and Stewart. ‘ Trans.,’ 111, 829 (1917). H Hexamethylbenzene. Lifschitz. ‘ Ber.,’ 49, 2050 (1916). Hexamethyltriaminotriphenylearbinol.. Hantzsch. ‘ Ber.,’ 52, 509 (1919). Hexatriene. Macbeth and Stewart. ‘ Trans.,’ 111, 829 (1917). é p-Hydroxybenzeneazo-1.3-dihydroxynaphthalene, Ghosh and Watson. ‘'Trans.,’ 111, 815 (1917). € _ p-Hydroxybenzeneazo-1.5-dihydroxynaphthalene. Ghosh and Watson. ‘ Trans.,’ 111, 815 (1917). 246 REPORTS ON THE STATE OF sctencE.—1920. p-Hydroxybenzeneazo-a-naphthol. Ghosh and Watson. ‘Trans.,’ 111, 815 (1917). p-Hydroxybenzeneazo-8-naphthol. Ghosh and Watson. ‘ Trans.,’ 111, 815 (1917). p-Hydroxybenzeneazo-#-naphthylamine. Ghosh and Watson. ‘ Trans.,’ 111, 815 (1917). 4-Hydroxymalachite-green. Ghosh and Watson. “ Trans.,’ 111, 815 (1917). I Imidovioluric acid. Lifschitz and Kritzmann. ‘ Ber.,’ 50, 1719 (1917). 3 » salts. Lifschitz and Kritzmann. ‘ Ber.,’ 50, 1719 (1917). Indigo. Lifschitz and Lourié. ‘ Ber.,’ 50, 897 (1917). K Ketothiodimethylpyrone. Hantzsch. ‘ Ber.,’ 52, 1535 (1919). M Malachite-green. Ghosh and Watson. ‘Trans.,’ 111, 815 (1917). Hantzsch. ‘ Ber.,’ 52, 509 (1919). Kehrmann and Sandoz. ‘ Ber.,’ 51, 915 (1918). ie a derivatives. Kehrmann and Sandoz. ‘ Ber.,’ 51, 915 (1918). Maleic acid. Macbeth and Stewart. ‘ Trans.,’ 111, 829 (1917). Martius yellow. Miethe and E. Stenger. ‘ Zeit. wiss. Phot.,’ 19, 57 (1920). Methoxymalachite green. Hantzsch. ‘ Ber.,’ 52, 509 (1919). a-Methylcinnamic acid. Ley. ‘ Zeit. wiss. Phot.,’ 18, 178 (1918). 8-Methylcinnamic acid. Ley. ‘ Zeit. wiss. Phot.,’ 18, 178 (1918). Methyl.o-formate. Hantzsch. ‘ Ber.,’ 50, 1422 (1917). Methylphenylthiazin bromide. Kehrmann. ‘ Ber.,’ 49, 2831 (1916). @-Methylstilbene. Ley. ‘ Zeit. wiss. Phot.,’ 18, 178 (1918). a-Methylstyrol. Ley. ‘ Zeit. wiss. Phot.,’ 18, 178 (1918). B-Methylstyrol. Ley. ‘ Zeit. wiss. Phot.,’ 18, 178 (1918). Methylthiazin perchlorate. Kehrmann. ‘ Ber.,’ 49, 2831 (1916). Monochloroacetic acid and salts. Hantzsch. ‘ Ber.,’ 50, 1422 (1917). Monosulphuryl indigo. Lifschitz and Lourié. ‘ Ber.,’ 50, 897 (1917). 9 ” ” ” N Naphthophenazoxonium derivatives. Kehrmann and Sandoz. ‘ Ber.,’ 51, 923 (1918). p-Nitrobenzeneazoanthranol. Sircar. ‘Trans.,’ 109, 757 (1916). p-Nitrobenzene-l-azo-4-anthrol. Sircar. ‘Trans.,’ 109, 757 (1916). p-Nitrobenzene-l-azo-4-naphthol. Sircar. ‘ Trans.,’ 109, 757 (1916). p-Nitrobenzene-1l-azo0-4-naphthol-3-carboxylic acid and salts. Sircar. ‘Trans.’ 109, 757 (1916). p-Nitrobenzeneazophenol, Sircar. ‘Trans.,’ 109, 757 (1916). p-Nitrobenzeneazosalicylic acid and salts. Sircar. ‘Trans.,’ 109, 757 (1916). p-Nitrobenzene-1-azo-1’.2'.3'.4'-tetrahydro-4-naphthol. Sircar. ‘Trans.’ 109, 757 — (1916). p-Nitrodiazoaminobenzene. Hantzsch and Hein. ‘Ber.,’ 52, 493 (1919). | p-Nitrodiphenylamine. Hantzsch and Hein. ‘ Ber.,’ 52, 493 (1919). ; p-Nitronaphthalene-l-azophenol. Sircar. ‘Trans.,’ 109, 757 (1916). 4 4-Nitronaphthalene-1-azosalicylic acid and salts. Sircar. ‘ Trans.,’ 109, 757 (1916). Nitrosodimethylaniline. Miethe and Stenger. ‘ Zeit. wiss. Phot.,’ 19, 57 (1920). p-Nitrotriphenylmethane. Hantzsch and Hein. ‘ Ber.,’ 52, 493 (1919). P Parafuchsin. Kehrmann and Sandoz. ‘ Ber.,’ 51, 915 (1918). Pararosaniline. Lifschitz. ‘ Ber.,’ 52, 1919 (1919). cyclo-Pentadiene. Stobbe and Diinnhaupt. ‘ Ber.,’ 52, 1436 (1919). Phenazoxonium derivatives. Kehrmann and Sandoz. ‘ Ber.,’ 50, 1667 (1917). Phenazthionium derivatives. Kehrmann and Sandoz. ‘ Ber.,’ 50, 1673 (1917). Phenol. Ley. ‘ Zeit. wiss. Phot.,’ 18, 178 (1918). Phenyl benzoate. Ley. ‘ Zeit. wiss. Phot.,’ 18, 178 (1918). a-Phenyl cinnamate. Ley. ‘ Zeit. wiss. Phot.,’ 18, 178 (1918). ON ABSORPTION SPECTRA OF ORGANIC COMPOUNDS. 247 Phenyl salicylate. Ley. ‘Zeit. wiss. Phot.,’ 18, 178 (1918). a-Phenyl stilbene. Ley. ‘ Zeit. wiss. Phot.,’ 18, 178 (1918). Phenylacetylene. Macbeth and Stewart. * Trans.,’ 111, 829 (1917). Phenylethylene. Macbeth and Stewart. * Trans., 111, 829 (1917). Phenylpropiolic acid. Macbeth and Stewart. ‘ Trans.,’ 111, 829 (1917). B-Phenylpropionic acid. Macbeth and Stewart. ‘Trans.,’ 111, 829 (1917). Phenylthiazin bromide. Kehrmann. ‘Ber.’ 49, 2831 (1916). Phorone. Lifschitz. ‘Zeit. wiss. Phot.,’ 16, 140 (1916). a-Picoline. Herrmann. ‘ Zeit. wiss. Phot.,’ 18, 253: (1919). B-Picoline. Herrmann. ‘ Zeit. wiss. Phot.,’ 18, 253 (1919). Picolinic acid. Ley and Ficken. ‘ Ber.,’ 50, 1123 (1917). Piperidine. Herrmann. ‘ Zeit. wiss. Phot.,’ 18, 253 (1919). Purpurin. Meek. ‘Trans.,’ 111, 969 (1917). Pyridine. Herrmann. ‘Zeit. wiss. Phot.,’ 18, 253 (1919). Pyridonium and Pyroxonium salts. Hantzsch. ‘Ber,,’ 52, 1535, 1544 (1919). Q Quinizarin. Meek. ‘Trans.,’ 111, 969 (1917). Quinone. Hantzsch and Hein.’ * Ber.,’ 52, 493 (1919). R Resaurin. Ghosh and’ Watson. ‘Trans.,’ 111, 815 (1917). SS) Salicylic acid. Ley. ‘Zeit. wiss. Phot.,’ 18, 178 (1918). Stearic acid. Macbeth and Stewart. ‘Tramns.,’ 111, 829 (1917): Stearolic acid. Macbeth and Stewart. ‘Trans.,’ 111, 829 (1917). Stilbene. Macbeth and Stewart. ‘ Trans.,’ 111, 829 (1917). 7 Ley. ‘Zeit. wiss. Phot.,’ 18, 178 (1918). Styrene. Macbeth and Stewart. ‘Trans.,’ 111, 829 (1917). Styrol. Ley. ‘Ber.,’ 51, 1808 (1918). ‘ Zeit. wiss. Phot.,’ 18, 178 (1918). Succinic acid. Macbeth and Stewart. ‘ Trans.,’ 111, 829 (1917). p-Sulphobenzene-l-azo-4-anthrol. Sirear: ‘Trans.,’ 109, 757 (1916). p-Sulphobenzene-1-azo-4-naphthol. Sircar. * Trans.,’ 109, 757 (1916). p-Sulphobenzeneazophenol. Sircar. ‘Trans.,’ 109, 757 (1916). p-Sulphobenzene-1-azo- 1’.2'.3/.4'-tetrahydro-4-naphthol. Sircar. ‘ Trans.,’ 109, 757 (1916). Aly Tartrazine. Miethe and Stenger. ‘ Zeit. wiss. Phot.,’ 19, 57 (1920). Tetrabenzylarsonium iodide. Hantzsch. ‘Ber.,’ 52, 1544 (1919). Tetraethylphosphonium iodide. Hantzsch. ‘ Ber.,’ 52, 1544 (1919). 1.2.5.8-Tetrahydroxyanthroquinone. Meek. ‘Trans.,’ 111, 969 (1917). Tetramethyldiaminofuchsone. Hantzsch. ‘ Ber.,’ 52, 509 (1919). Tetramethyldiaminoquinone. Hantzsch. ‘Ber.,’ 52, 509 (1919). Tetrapropylammonium iodide. Hantzsch. ‘ Ber.,’ 52, 1544 (1919). Thiazin chloride. Kehrmann. ‘ Ber.,’ 49, 2831 (1916). Tolane. Macbeth and Stewart. ‘Trans.,, 111, 829 (1917). Trialkylsulphonium haloids. Hantzsch. ‘ Ber.,’ 52, 1544 (1919). Trichloroacetic acid and salts. Hantzsch. ‘ Ber.,’ 50, 1422 (1917). 1.2.4-Trihydroxyanthraquinone. Meek. ‘ Trans.,’ 111, 969 (1917). Trihydroxyaurin. Ghosh and Watson. ‘Trans.,’ 111, 815 (1917). 2.3.4-Trihydroxymalachite-green. Ghosh and Watson, ‘ Trans.,’ 111, 815 (1917). Trinitrobenzene. Hantzsch and Hein. ‘ Ber.,’ 52, 493 (1919)... -p-Trinitrotriphenyl carbinol. Hantzsch. ‘Ber.,’ 50, 1413 (1917). Trinitrotriphenylmethane. Hantzsch and Hein. ‘Ber.,’ 52, 493 (1919). Triphenylearbinol. Hantzsch. ‘ Ber.,’ 52, 509 (1919)... +s Kehrmann and Sandoz. ‘ Ber.,’ 51, 915 (1918). Triphenylmethylphosphonium iodide. Hantzsch. ‘ Ber.,’ 52, 1544 (1919). a-Truxillic acid. Stobbe. ‘ Ber.,’ 52, 1021 (1919). 8-Truxillic acid. Stobbe. ‘ Ber.,’ 52, 1021 (1919). 248 REPORTS ON THE STATE OF SCIENCE.—1920. Fuel Economy. Third Report of Committee (Professor W. A. Bone * (Chairman), Mr. H. James Yares * (Vice-Chairman), Mr. Ropert Monn * (Secretary), Mr. A. H. Barxsr, Professor P. P. Bepson, Dr. W. S. Bouton, Mr. E. Bury, Professor W. E. Dausy, Mr. E. V. Evans,* Dr. W. GauLoway, Sir RoBert HapDFIELD, Bart. ,* Dr. H. 8. Heue-SHaw,* Mr. D. H. Heures, Dr. G. Hickuina, Mr. D. V. HouttinewortH, Mr. A. Hurouinson,* Principal G. Knox, Professor Henry Louis,* Mr. H. M. Moraans, Mr. W. H. PatcHety,* Mr. A. T. Smita, Dr. J. E. Sreap, Mr. C. E. StroMEyER, Mr. G. BuakE WALKER, Sir JosEPpH Watton, M.P.,* Professor W. W. Warts,* Mr. W. B. WoopuHovss, and Mr. C. H. WorpDINGHAM*) appointed for the Investigation of Fuel Economy, the Utilisation of Coal, and Smoke Prevention. Introduction. THe Committee has held altogether six meetings since its reappointment last year, and is investigating (inter alia) the following matters, namely :— (a) The present official methods of arriving at coal-mining statistics (e.g., outputs of coal, etc.) in thig and other coal-producing countries, (6) The effect of the war upon the British coal export trade. (c) The chemical constitution of coal. (zd) The low temperature carbonisation of coal. (e) The thermal efficiencies at present attainable (i) in the carbonisation and gasification of coal by various systems, (ii) in domestic fires and heating appliances, (iii) in metallurgical and other furnaces, (iv) in steam raising and power production, and (v) in regard to the generation of electric power in public stations. (f) Sources of supply of liquid fuels. Although the Committee has made satisfactory progress with its inquiries in certain directions during the past year, both time and opportunity have been wanting for completing them. ‘Che present Report, therefore, is of an interim nature, but the Committee hopes to report more fully on the above matters to the Edinburgh Meeting next year. Coal-maning Statistics. The attention of the Committee having been drawn by Professor Henry Louis to the fact that, owing to considerable variations in the modes of arriving at the official data concerning coal outputs, etc., periodically published by Government Departments in the various coal-producing countries, it is impossible to regard them as being properly comparable, the Committee requested him to prepare a Memorandum on the subject. This he subsequently did, and, having regard to the great importance of the matter, the Committee decided to publish the Memorandum im extenso as Appendix I. to this Report, in the hope that it may lead to the desired: reform being effected. In particular, the Committee endorses Professor Louis’ view concerning the importance of summoning an International Conference for determining the precise manner in which mineral statistics of all kinds shall be collected, tabulated, and finally issued to the public. * Denotes a member of the Executive Committee. ON FUELS ECONOMY. 249 Coal Outputs and Average Pithead Prices in 1919. According to information kindly furnished to the Committee by the Statistical Department of the Board of Trade, the total output of coal in the United Kingdom during the year 1919 has been provisionally estimated at 229,668,000 tons, and the total output per person employed (below and above ground) in the mines at 197°5 tons. Owing to abnormal circumstances during the period of coal control, it is difficult to give strictly comparable figures for the average pithead prices of coal in the years immediately preceding and following (respectively) the war. According to official estimates supplied by the Statistical Department of the Board of Trade, the pithead prices per ton of coal raised in 1913, and in July 1919, respectively, were approximately as follows :— Average On July 16, for 1913 1919 8. d. 8. d. Labour . 4 : 6.4 19 53 Timber and Stores . : - HoH GO 3 2h Other Costs . f : : : 10 SOY 1 24 Royalties : E ? ’ - O 5} 0 62 Owners’ Profits : : SORMAG 1 2 Compensation . : . : ; : — 0 3} Administration, etc. z 3 ‘ 3 — 0 24 Total . t ’ - 10 26 04 In the Report recently made to the Prime Minister by Messrs. Alfred Tongue & Co., Chartered Accountants, of Manchester and Glasgow, and presented to Parliament by command of His Majesty (Cmd. 555), it was estimated that the average cost per ton of coal raised in British mines during the year ending March 31, 1920, was as follows :— 8. d. Wages 4 : : : : : : Z of dD yh Timber and Store , 2 . - . F eet S10 Other Costs : ; : 7 : - Spi A Lye) Royalties , - ; ; ‘ : : - O 63 Administration . : : s A ‘ ; oy Ot ve Capital Adjustments under Finance Acts . nv. Control and Contingencies 0 2 Owners’ Profits . 1 2 Total . ‘ : : . : - 27 3f It would thus appear that the pithead cost of coal has been nearly trebled as the result of the war. Coal Hxport Statistics, The Statistical Department of the Board of Trade has also placed at the disposal of the Committee detailed information concerning the amounts of coal exported from the principal ports of the kingdom (a) to British possessions, and _ (6) to foreign countries, during each of the years 1913-1919 inclusive. In view of the importance of such statistics, the Committee has decided to publish them in tabular form as Appendix II. to this Report. The Committee is also collecting information as to average prices obtained at the principal ports for the coal exported during each of the years in question. In the light of such statistics the Committee hopes next year to be able to review the question of the effect of the war upon the coal export trade. “ Chemistry of Coal. . During the year considerable progress has been made with the researches on the chemistry of coal under the direction of Professor Bone at the Fuel Laboratories at the Imperial College of Science and Technology, further details 250 REPORTS ON THE STATE OF SCIENCE.—1920. of which will shortly be published. The Committee has also followed with close. attention the work recently published (a) by Drs. Marie Stopes, R. V. Wheeler, and Rudolph Lessing upon the four macroscopically distinguishable portions of banded bituminous coal and their respective behaviour on car- bonisation and oxidation, (0) by Mr. 8. R. Illingworth at the Treforest School of Mines, and (c) by Mr. F. 8. Sinnatt and collaborators of the Lancasnrre and Cheshire Coal Research Association. Future Standards of Gas Supplies. Since it reported its views on the above subject to the Bournemouth Meeting of the Association last year, the Committee has followed up the matter, and on February 2 last a deputation, consisting of the Chairman, Sir Robert Hadfield, Messrs, W. H. Patchell and H. James Yates, waited upon the then President of the Board of Trade (the Rt. Hon. Sir Auckland C. Geddes, K.C.B.) to lay before him the views of the Committee upon the subject, with special reference to impending legislation. In introducing the deputation, Professor Bone called the attention of the President to (a) the Report on Gas Standards which had been made by the Fuel Research Board, (6) the conclusions thereon that had been arrived at as the result of a conference between representatives of consumers, local authorities, and gas undertakings, and (c) the announcement by the President of the Board of Trade that a Bill would shortly be introduced in Parliament to give effect to the recommendations of the Fuel Research Board.! He explained that the Com- mittee had looked at the question primarily from the view of the national interests as a whole, and particularly from that of domestic and industrial gas consumers. It agreed with the Fuel Research Board that the future basis of charge to the consumer should be the actual number of thermal units supplied to him in the gas which passed through his meter, but desired that the charge should be based upon the ‘ascertained net calorific value’ of the gas supplied rather than its ‘ declared calorific value,’ as proposed by the Fuel Research Board. It also endorsed the Fuel Research Board’s original recommendation that the gas should be supplied at a pressure of ‘not less than two inches of water at the exit of the consumer’s meter,’ but expressed its disagreement with the Board’s subsequent view that the pressure condition might be reduced to one of ‘ not less than two inches of water in any main or service pipe of two inches in diameter’; because what mattered to the consumer was the adequacy of the pressure in his own pipes rather than in the gas mains outside his premises. It was also stated that the Committee attached great importance to the pressure being maintained as constant as possible, as well as to gas undertakings being required to pay greater attention than ever to the removal of cyanogen and sulphur impurities from the gas. Finally, it was explained that the Com- mittee, whilst agreeing generally with the proposals in regard to the new thermal basis for the sale of gas, and to the restriction of its inert constituents, con- sidered that its chemical composition would need some statutory regulation, and that in particular no public gas supply should be allowed to contain less than 20 per cent. of methane or more than 20 per cent. of carbon monoxide. After Sir Robert Hadfield had endorsed the views of the Committee from the point of view of industrial consumers of gas, Mr. H. James Yates outlined his views as a maker of gas fires who had for many years given much attention to the scientific investigation of domestic heating and ventilation. He laid stress upon the importance of maintaining a constant pressure of not less than ~ two inches water-gauge on the consumer’s side of the service pipes, and that the gross calorific value of the gas supplied should not be allowed to fall below 450 B.Th.U. per cubic foot, stating that if gas undertakings supplied gas of | lower calorific value a large part of the existing gas appliances would become useless. Sir Auckland Geddes, in his reply, promised to give full consideration to the facts and opinions which they had laid before him. Also, he said that he 1The Bill was subsequently introduced by Sir Robert Horne in the House of Commons on May 19, 1920. ON FUEL ECONOMY. 251 had been impressed with the physiological side of the question and with the danger of cyanogen and of too high a proportion of carbonic oxide in gas. The ‘Gas Regulation Bill,’ as subsequently presented to the House of Commons on May 19 last by Sir Robert Horne (the new President of the Board of Trade), contained far-reaching new proposals concerning the public sale and distribution of gas, among which the following are of especial importance ‘to consumers :— (a2) That the Board of Trade may, on the application of any gas undertakers, by order, provide for the repeal of any enactments or other provisions requiring the undertakers to supply gas of any particular illuminating or calorific value, and for substituting power to charge for thermal units supplied in the form of as. F (6) That where such substitution has been decided upon, the new basis for the sale of gas shall be 100,000 British Thermal Units (to be referred to in the Bill as a ‘therm’). The consumer will then be charged according to the number of ‘therms’ supplied to him in the gas, and the standard price per therm fixed by the order shall be a price corresponding as nearly as may be to the price fixed by former provisions for each 1,000 cubic feet, but with such additions (if any) as appear to the Board to be reasonably required in order to meet unavoidable increases since June 30, 1914, in the costs and charges of and incidental to the production and supply of gas by the undertakers ; and the order may make such modifications of any provisions whereby the rate of dividend payable by the gas undertakers is dependent on the price of gas supplied as appear to the Board to be necessary. (ec) That an order under the Act shall prescribe the time when, and the manner in which, the undertakers are to give notice of the calorific value of the gas they intend to supply (#.e., ‘declared calorific value’), and shall require the undertakers, before making any alteration in the declared calorific value, to take at their own expense such steps as may be necessary to alter, adjust, or replace the burners in consumers’ appliances in such a manner as to secure that the gas can be burned with safety and efficiency. (d) That the gas supplied under the Act (i) shall not contain any trace of sulphuretted hydrogen, (ii) shall not be at a pressure of less than two inches water-gauge in any main or service pipe of two inches diameter or upwards, and (iii) shall not contain more than a certain permissible proportion of incombustible constituents (namely, 20 per cent. during a period of two years after the passing of the Act, 18 per cent. during the succeeding two years, and 15 per cent. thereafter). (e) That as soon as may be after the passing of the Act the Board shall cause an inquiry to be held into the question whether it is necessary or desirable to prescribe any limitations of the proportion of carbon monoxide which may be supplied in gas used for domestic purposes, and may, if on such inquiry it appears desirable, make a special order under the Act prescribing the permissible proportion. (f) That Gas Referees and Examiners shall be appointed for the purpose of (i) prescribing the apparatus and method for testing the gas, and (ii) carrying out of such prescribed tests. During the passage of the Bill through its Committee stage in the House of Commons, the important sub-section limiting the amount of incombustible con- stituents permissible in gas (vide (d) (iii) above) was deleted, on the under- standing that, subsequent to the passing of the Act, the matter shall be made the subject of an official inquiry by the Board of Trade. The effect of this amendment is, therefore, to put the question of ‘inerts ’ into the same category as that of carbon monoxide, and the whole matter now stands as follows :— The Board of Trade shall, as soon as may be after the passing of this Act, cause inquiries to be held into the question whether it is necessary or desirable to prescribe any limitations of the proportion of carbon monoxide which may be supplied in gas used for domestic purposes, and into the question whether it is necessary or desirable to prescribe any limitations of the proportion of incombustible constituents which may be supplied in gas so. used, and may, if on any such inquiry it appears desirable, make one or more special orders under this Act prescribing the permissible proportion in either case, and any such 252 REPORTS ON THE STATE OF SCIENCE.—1920. special order may have effect either generally or as regards particular classes of undertakings, and the provisions of the special order shall have effect as if they were enacted in this section. When such official inquiries are instituted by the Board of Trade this Com- mittee will hope to be given an opportunity of presenting again its views (as already reported) upon the matters concerned. Alcohol from Coke-oven Gas. During the past year a notable development has been made in connection with the technology of by-product recovery from coal as the result of Mr. E. Bury’s successful experimental trials, in conjunction with Mr. O. Ollander, at the Skinningrove Iron Works, upon the absorption of ethylene from debenzolised coke-oven gas and its conversion into ethyl alcohol. These trials have demon- strated the possibility of obtaining on a large scale 16 gallons of absolute alcohol per ton of the particular Durham coal carbonised. Assuming’ a similar yield from the 15,000,000 tons (or thereabouts) of coal now annually carbonised in British by-product coke ovens, it is claimed to be possible to obtain from coke works alone a 95 per cent. industrial alcohol in quantities equivalent to about 24 million gallons per annum of the absolute spirit. Although a full account of the investigation has already been given by Messrs, Bury and Ollander in a paper before the Cleveland Institution of Engineers in December last (vide also Iron and Coal Trades Review, December 1919), the Committee, whilst not expressing any opinion as to the commercial prospects of the process, considers that the technical importance of it is such as to warrant attention being drawn in this Report to some of its salient features (see Appendix IIT.). The Committee recommends that it be reappointed to continue its investi- gations, with a grant of 351. AppENDIx [. Memorandum upon Coal-mining Statistics. The most important statistics concerning coal are the figures giving the annual production of coal, the number of workers employed in the mines, the number of fatal and of non-fatal accidents respectively. These statistics are collected and published by the Government Departments in most coal-producing countries, and upon these are based a number of comparative statements by which the progress of the industry in different countries is usually estimated, such as the production per worker employed, the accident death-rate per thousand workers, etc. For most economic and social studies, the number of workers employed is in several respects the most important of these figures, and un- fortunately it would appear to be the one upon which the least dependence can be placed. Elaborate reports have been drawn up, and legislation has even been enacted, based upon the comparative results of these data; and it has been quite freely assumed that the figures given for different countries or different districts of a country are properly comparable, whilst as a matter of fact the methods of arriving at these figures vary so widely that they come to bear quite different meanings, and the assumption that similar headings always connote similar interpretations is utterly without foundation. Production.—In this country the returns of the output of coal until recently included the stones and dirt sent up to ‘bank with the coal and picked out on the belts or screens; since that time the weight of coal alone is supposed kos Re returned. The instructions at present issued by the Home Office read as follows :— The weight given should be the net weight after screening or sorting. .. . Where the net weight of the coal is not determined during the year in respect of which the return is being made, it will be sufficient if a deduction is made according to the average percentage of dirt ex- tracted from the coal at the mine. In cases where the coal is sold as it leaves the pit without screening or sorting it will be proper to give the gross weight sent out of the pit as the amount of output. ON FUEL ECONOMY. 253 It will be seen that the instructions are somewhat vague, and that. they also leave considerable openings for guess-work and estimates instead of accurate facts; furthermore, the instructions would in, some cases at any rate compel the inclusion of washery dirt under the heading of output, since this dirt does not always come under the heading of ‘ dirt extracted from the coal at the mine.’ It is by no means uncommon for one company to control two collieries not far distant from each other and to erect at one of them a washery to which the small coal from the first colliery is to be sent for washings; in such a case if the instructions are literally followed, washery dirt will be included in the returns of the coal output from the first colliery and excluded from the second. Accordingly, it is natural that the practice in making up these returns varies greatly from district to district, and even from colliery to colliery. In some cases both the dirt picked out on the belts and that washed out in the washery are deducted from the pithead weight, 7.e., from the tonnage on which the men are paid; in other cases no deduction at all is made for washery dirt, and in yet other cases an arbitrary percentage is deducted from the coal sent to the washery. There is also some difference as regards the practice concerning ‘free coal’ given to the’ miners and coal for colliery consumption. In most cases all this coal is returned as part of the production; in some cases the coal consumed by the pits is not included, and apparently in a few cases both the ‘free coal’ and coal for colliery consumption are deducted from the output. In some places it is customary to give as a return of output the landlord’s tonnage, that is the amount on which royalty is paid, which is usually the output less certain deduc- tions allowed by the terms of the lease. In view of this wide variation, it would be a distinct advantage if the Home Office were to issue specific instructions on all the above points, so as to secure uniformity of method in making returns throughout the United Kingdom. The methods used in Canada might well be adopted here. In Canada a more definite system is adopted; the introduction. to the Canadian Annual Statistics states in definite language what is intended, as follows :— The term ‘production’ in the text and tables of this report is used to represent the tonnage of coal actually sold. or used, by the producer, as distinguished from the term ‘output,’ which is applied to the total coal extracted from the mine, and which includes. in some cases, coal lost or unsaleable or coal carried into stock on hand at the end of the year. Apparently throughout Canada the various Provinces issue sheets which have to be filled up every month, and which the different Provincial Govern- ments have agreed to issue in identical form, so that returns for the Dominion can be made by the Canadian Department of Mines or by the Dominion Bureau of Statistics. The whole of the collection of statistics, and, in fact, the administration of mining law, is controlled by the respective Provincial Govern- ments. with the exception of mining lands in certain of the Western Provinces and North-West Territories, which are controlled directly by the Dominion Government. These monthly returns show the amount of free coal or of coal sold to miners at a reduced price, the quantity used for colliery consumption. specifying any used on the colliery company’s own railways, the quantity of coal used for making coke and briquettes, the quantity stocked, and the quantity on hand. The only fault that can be found with these returne is that they do not specifically ask for a return of the dirt picked out and washed ont respectively. In Canada the term ‘production’ is restricted. to marketable or economically useful coal. whilst the term ‘output’ is the equivalent of what we sometimes speak of in this country as ‘drawings,’ i.e., everything drawn out from the colliery, inclusive of any dirt that may be extracted subsequently. In the United States. the production means the total production of clean coal. that is to say, coal with the exclusion of pickings and washerv dirt, and includ- ing colliery consumption. Tho work is done by the Mineral Resources: Division of the United States Geological Survey, but there is a cood deal of overlapping and difficulty owing to some of the statistics being collected by State Bureaux and others by Federal Bureaux: in this resnect attention may be directed to. the Conference on this subject held at Washington in 1916. the results of which are printed in a report of the Committee on the Standardisation of Mining O54: REPORTS ON THE STATE OF SCIENCE.—1920. Statistics in 1918. At present cards in the shape of card slips are issued, to be filled up annually, and these ask for the total production, which is defined to ‘include all marketable coal, excluding only refuse from washeries and slack coal wasted.’ It distinguishes between the coal loaded at the mine for ship- ment, coal used locally, colliery consumption, and coal used for making coke at the mine. It will be seen that these instructions are fairly clear and definite. In France the production includes the whole of the drawings, deducting only the worthless waste, 7.e., pickings and washery refuse, In Belgium the same practice is followed, the production including colliery consumption and coal given or sold to employees, but definitely excluding pickings and washery waste. It will be seen that all these producing countries are aiming at one definite meaning for the word ‘production,’ and in this respect there is at any rate uniformity of intention. Unfortunately the execution of the object leaves much to be desired. The Canadian practice of monthly returns has much in its favour ; it no doubt throws a certain amount of additional work both upon individual collieries and upon the department collecting statistics, but, on the other hand, it enables half-yearly and quarterly statements to be issued very shortly after the conclusion of the respective periods, and in the same way annual statements can be produced much more rapidly than would be the case if the whole of the returns began to come in after the end of the year. It is quite desirable that the returns should show definitely the total weight of drawings, the weight of dirt picked and washed out, the weight given or sold to employees, the colliery consumption, and the coal used for making coke. Again, there would not be a great deal of labour involved in keeping these figures, and the information would be of the greatest value. Number of Employees.—In this country the only information asked for is a return ‘ of persons ordinarily employed ’; the returns specify that it must include all the persons employed on the mine premises, such as officials, storekeepers, clerks, etc., those employed on the pit sidings, on private branch railways and tramways, and in washeries adjacent to and belonging to the mine. Furthermore, the number employed underground must be kept separate from those employed above-ground, and there is also a separation according to age and sex. There is, however, no information as to what is meant by ‘the number of persons ordinarily employed.’ although this is evidently the crux of the whole matter. The consequence is that extremely variable methods are made use of. Some pits merely give the number of men entered on the pay sheet for the particular day in the year on which the return is made out; others take two or three days which they consider normal and average these. Some return the number of employees on the books of the company, others the number on the time roll; with the prevailing amount of absenteeism, the former number will exceed the latter by about 25 per cent., but there is no instruction as to which of the two is the figure intended to be given. Some of the more painstaking collieries average the number of men employed daily, but this is apparently exceptional. It is evident that a more definite and svstematic method would have to be adopted before it is possible to attach anything like a precise meaning to returns of numbers employed in this country. In Canada, apparently, monthly returns are made, and these are averaged for the year. The Canadian intention is to ‘show the actual amount of labour in terms of days worked, rather than the actual number of individual men that may have been engaged,’ and this is obviously the correct way of dealing with the subject. The returns ask for a classification under eight different heads and separate them into underground and above-ground workers; it may be noted that in Canada the number of men employed at the coke ovens and briquetting plants in connection with collieries is included in the mine employees. whilst according to the wording of the English return these should be excluded in this country, although there is no warranty for saying that the instructions for making the latter returns are in all cases strictly complied with. Further- more, in Canada there is an interesting table showing the time lost through absenteeism, meaning thereby the fault of the men and through a series of other reasons which may be classified as the fault of the mine or of the industry. It would be a distinct advantage if such returns were available for this country. j ON FUEL ECONOMY. 255 In the United States of America the information asked for is the average number of men employed during the year, excluding coke workers and office force. In the exclusion of the latter item this return differs from the British return; in the exclusion of the former item it differs from the Canadian return. The number of hours per working day is also asked for, as well as the average number of days lost by strikes and the number of men thereby affected. The intention in America is to get the average number of men employed during the year, but apparently the methods of obtaining these are about as vague as they are in this country. In the report already referred to it is stated that ‘ without instruction in regard to the way these averages (average number of employees) should be computed there will be a lack of uniformity of method, and in many cases the figures submitted will not be averages, and will not represent even approximately the real average number of persons employed.’ No one with any experience of the subject will doubt the accuracy of this statement, and it is certainly applicable to countries other than the United States. In the report in question the definition is put forward that ‘the average number of men should be the actual number of man-hours for the year.” This obviously is a clear and intelligible definition, and it would probably be a great advantage if it were generally adopted. In Belgium this principle is carried into effect; the number of employees returned represents the quotient of the number of days’ work done in the year divided by the number of working days. This figure is thus really the mean number of workmen engaged during the working days. In France, on the other hand, the number of employees is intended to be the number of names regularly on the colliery pay roll; a column is reserved for the number of days worked in the year. It is obvious that we are dealing here, under the same heading, with two entirely different conceptions ; some countries return the number of men who normally get their living by the industry, without any regard to the amount of absenteeism or the length of time that these men may be at work, whilst others return the number of men who have put in a full year’s work, meaning thereby have worked on all the days on which the mine was in operation. Obviously, these two figures differ widely from each other, and the fact that both are returned indifferently under the same heading vitiates many of the conclusions that have been drawn upon the basis of these returns. Fatal Accidents.—It is a curious fact that whereas every coal-mining country publishes a return of fatal accidents, there appears to be in none of them any legal definition of what constitutes a fatal accident. In the absence of legal definition in this country the Home Office has for many years made a practice of classifying all mine accidents which result in death within a year and a day as fatal accidents, apparently for no better reason than that in so doing they have followed the old Coroner’s Law. In Canada the Mineral Resources Statistics Branch does not collect accident statistics, and these appear to be left to the relative departments of different Provinces. They are not asked for in the statistical returns, but are obtained from the reports to the Inspector of Mines. In the Province of Alberta a fatal accident is construed as an accident which causes death within a twelvemonth. In the other Canadian Provinces there appears to be no definition at all, and it would seem that if a man dies from the effect of a mining accident, however long the death may be after the accident, it would apparently be reported as a fatal accident for the year in which the death takes place. In the United States mine-accident statistics are gathered by the various States and are by no means as reliable as statistics gathered by the Bureau of Mines. Mr. G. S. Rice. the chief mining’ engineer of the Bureau of Mines at Washington. gives me the following information: ‘As to what constitutes a definition of a fatal accident, this varies in the different States. In some States it means immediate death, in others within a day or two, in still others, if the man dies from the direct cause of the accident before the report is turned in, which is in February for the preceding calendar year, which may mean from two to thirteen months after the accident.’ Tt will be seen that these figures are obviously vague and unreliable. It is a curious fact that in the report of the Com- mittee on the Standardisation of Mining Statistics already referred to, the terms fatal and non-fatal accidents are freely used, but there is no attempt at definition. 256 REPORTS ON THE STATE OF SCIENCE.—1920. In France the principle followed is that the records of fatal accidents are restricted to those who are mortally injured in a mine accident, that is to say, either those killed on the spot or who die as the result of their injuries within a few hours after the accident, or at the outside within a few months without ever having been able to resume work. With regard to those whose death, occurring after a considerably longer interval, is the consequence of injuries received, they do not appear on the record, the Statistical Department not being, as a rule, informed of their death, and being, moreover, unable to determine its real cause. In Belgium, on the other hand, a fatal accident is restricted to an accident that causes death within thirty days. Here, again, it may be pointed out that this extremely important matter is in a chaotic condition, and that it is most urgent that an agreement be arrived at as to what precisely is meant by a fatal accident. Non-Fatal Accidents.—Here, again, there is a wide variation to be noted in practice. In this country the return is asked for of non-fatal accidents within any given year, non-fatal accidents being defined as accidents disabling the victim for more than seven days. In Canada the practice varies in the different Provinces. Apparently in Nova Scotia a non-fatal accident is classified as an accident by which a man must be disabled for at least seven days, but from which he recovers. In the Province of Saskatchewan accidents entailing a disability of less than six days are not recorded. In Alberta a non-fatal accident must be reported if a man is off for more than fourteen days; apparently in some cases accidents involving a disability of less than fourteen days are tabulated as slight accidents. In the United States of America the question of what constitutes a non-fatal accident is even more unsettled than the definition of a fata) accident. In some of the States statistics are collected based on the State Compensation Acts, under which compensation is paid for an injury causing a loss of at least two weeks; in metal mines apparently an accident causing a loss of at least one shift is tabulated as a slight injury, and one involving a loss of two weeks as a serious injury. In France injuries causing disability to work for more than twenty days are counted as non-fatal accidents. In Belgium all non-fatal accidents are accidents that cause permanent disability, whether this be total or partial, accidents involving only temporary disability not being included in the returns. The above can only be looked upon as an attempt to supply a portion of the information which is evidently needed before it is possible to read coal-mining statistics at all intelligently. It will be obvious, however, from what has been said, that attempts at comparisons, which have been so freely made without taking into account the striking differences in interpretation given above, must result in wholly inaccurate comparisons. I sincerely hope that the data here given may be further extended to all coal-producing countries, and I wish to urge again, as I: have done in more than one International Congress, the import- ance of an International Conference for determining the precise manner in which mineral statistics of all kinds shall be collected and tabulated, and the precise meaning that should be attached to the various headings. Henry Lovts. bh mee? x us ON FUEL ECONOMY. O0Z‘EFO'TS | ZOT*LEL‘9S | LI‘9TS*6S FSF LSO'T IZU‘12a'T GLO‘OLZ'T 680°689 OLL‘ssz 91°60 €IsFst | LIFSIT G69°66I GOZ‘68I | 286'69T OTS LES $6 L | 0006 FSTEL SEL‘esl 9ST‘61 S1S‘OF SIe6et | sze‘Tr OFS*SI LOG‘GF | = = 9FO'TEO'F OLs*ecoF 096‘0FI'F FSc9e | = 1¥9‘8E OFL‘E08 $00°62F 080°ELL 6F L'6S | 19g‘ ¥E0°SS G18'66 | SpE‘Or IL8‘1OT COS FFG =| S8ESLFT 980‘8F% 160°€¢ OFE‘09T $0919 96S°F0Z‘9T | SOO‘LIS‘OL | SPS°SIS*LT 69L‘SFT | OFBF = 106‘10F | 100°88 618‘9LE 108‘ = = TILGPL‘T IOL‘SH0'T Lg0‘9S8 9F90EET L98°0S3'T L&G‘6S0'T FOES6S'T =| «ISL‘TSO'T ELo°e19 O6FIZS = HL T‘82T G00°SL0T 6161 SI6T LI6I 606°CFS‘9E $S9'06¢ SLF8SL GLYELI €L6°961 F6L‘FS L86°¢ 901‘89T 860°01L°¢ G98°66 668°L00°S 6E1'9F SIS‘OF SIS F6L €08°ISL LLS‘TIE* LT 6C19FE'T 60F'S08°S 691‘ L08‘s Z0S‘9F9'T $08 9T6T GSOE60' TF | TGP LP9FS | O00'616'L9 £20°68¢ LOL‘6LS GLE‘FIOT €09‘S819'T #90°S88‘ ZLS‘S69°E TPS°SES 9L8°0S¢ 98681 OFS 867 OSL‘OLIT TL8°988'T LOV‘9P GSP LLE 92S°88¢ $26 01 909°6F 68L°69E = 81Z‘81z G26 ISG 861°60E LGL‘SLa 668°LZL = G9 ‘F9S $§9°9S0'T 09F'88L'¢ $9'939'8 19T‘L#9°6 089°0LF 98L°6L9 669°FIT‘T $80‘ L6S°T 6960966 IglFES‘s OLS‘T9 8LE°L8 ISL‘T&1 €68°SF 689°8E 809°%S G66 916 809°8F0'T ZoL‘106'T 9F8°686 I1Z‘016 $99°182'T T9S‘TOOLI | SFSOSsSI | 606‘SLL‘ST = $OG‘SOLT LLO‘T80% 1S6°Z6L'T GSIS‘SSL‘T 10F‘810°S = GOL‘99s‘¢ 83E‘SS6'8 GP9OST'S Z9T690'S OFS ‘FE0'S L8T‘Eb9°S 002‘29F'S GPS‘860'S G66°699°S G93 ‘096'F 9L0°899°F 699°ZP ¢08°L80°¢ PEr'866°S 9161 FI6I SI6I =] SOLIJUNOD) USIOIO,T 07 [PIO], . SolIyUNOD UsTIEI0,7 1073O onqudey ouIyuesIy AensnigQ 5 “7 ete d Le) : *- oyrny, : * erUeUINoyy : * — ga9er¥) Aresunyy-1ysny oe rege spurs] Areurp - uredg : “BILepeyy : * so10zy : * pesnyi0g : * BLLOs,y : - goue diy : * wnisjeq - - spuepToy ONT : > Aweuls1ey (spuepsy eore yl Surpnyout) yreuueq + eMION : * wepeamg : ‘eISSN yy PeUusisuoo YoryA 0} sermzuNO— *paubrsuoa yarym 0} sar.4unog podiaursd ay, burysinburysip ‘aarsnpaur GIGI 92 SI6L 8“vah ayy fo yova ur wophury pajug ay) worl parsodxa poop fo suoy, burmoyg ‘y Wavy, ‘T] xlanaday 1920 REPORTS ON THE STATE OF SCIENCE.—1920. 258 s9c‘6rs'es | POO'TELTE LEL‘GeerE | Ega‘tgs‘se | Ogg‘rEg'sh | O8s‘6cO'6o | SIT‘OOPEL | ° *(mopZury poyug wWosZ) TVLOT, 668°SFL B69°SIS‘T 163‘F99T | 880°L6Z'S | B00FSL'S | FHS‘TOS'S | FLPSIS | * ; 4880) 480M } sqrog Ysy300g 9LT*G06‘T 68 L‘861‘T L¥E ‘O16 GFrF00'G | SE6EZL'€ | S90°LLI‘O | Ez0°ESs's | ° ; 4qseoD se ; IL¥‘08g GILSLI9T =| | FSLSSI8‘T €96°F08'T B68‘ T6LS IPL'6r0'9 =| sgs‘ess’s | * : ; : * s}og Jequny SEP IOL'IL | 966'8F6'6 IP8‘ZOT‘OL | GLZ‘6sEEl | OFO'SET*PI | O8GTPS‘GT | O18*EZO'ES | * : ; * spod W1eyseq -Y}ION 83L°98 €12°669 L€6°899 PEL‘98P F1S‘bz9 61L‘009 618‘T9L ; : : * S}IOg WI0}82M\ -YWON Z086ZS'0S | FES‘OOO'LT | STOEES‘ET | LOL‘LIP*LE | 968°L09°ST | I¢S‘GLF‘Fs | 9T6°SL8‘6S | * ; 3 SWOg [OUUBYD [OSI 6I6T | — 8T6T LI6T 9T61 SI6I FI6I eI6l “aMIsnpUr GIGL O2 SIG s4vah ay? burunp wophury popuy ayp fo sjor.1281p pauoyuausapun ayy fo yone wolf pajsodaa qo0p fo suo, Bbumoyy ‘qd wavy, g9c6rs'as | POGZELTS | LEL‘G66'rs | sea‘tge’ss | Ogg‘PEa'sr | O8s*6EO'6S | SIT‘OOP'EL | ° IVLOL 89€'906'F SPL'aee'y 0F969F'S FF9'808'T £09‘0FK'S 686‘86E°F SIL TsPg | ° suormssessod Ystg OF [870], EPL‘9E F08°99T 892°08S L96‘8L LOP‘OFT LES‘E8P SIL‘Pee : : * suorssossog YsHg 10430 O6F'FE PREFS 08°62 91¥‘0S CEP LO SLOPE LLO‘LZ ; ; ; i} ae da I¥3‘Z1 FF, + sa a 9Lg‘OI 80F'Zo ; ; ; : Su0yy ence GOs‘sI =a TPSST 9B L‘Sz L8P‘SP ELI09 LE9‘6ES ; 2 * seruepuede pue uophep 6LP6F a GZ6°3 GE6'63 GLYZET - 18681 F0Z 181 F ; * — serouspuedeqy pue el Ad 9818s £0% 0S9°8T 886'6F 18°96 89886 = "7 + uepnog usd Saa-opsEy: £EE'8h 668°09T 8h9'96G 9811 B6P'ES PEa‘gE 209‘0F ttets. 2 eae S9TSL9'T | S806L69° | ISS PLT | 868°rP8 SLo‘zosT | soLiveg’s | Livcot'e | °° 7: yee GPO'SEL €88°961'L g89°6ZLl | PSL‘P8 eSl‘Isl €L9‘8EE ITT‘00L : : ; _ 0208) PUB EEN 98 L'C9OF‘T 286°S19‘T OFEFZS'T OST LIg 910°99E 029608 BOLFSE : : ‘ F TeqeIGLH LEOFIT 91986 609°00T 618‘SIT OLLIET 990°C9T 698° LOT 3 : j ; spurs] jouueyD 6161 S161 LIGI 9161 S161 FIGI e161 peusisuoo YoryA OF sor1zUNO/ | I se ‘paubiswoo yorvym 072 sar.tzunoy qodnawad ay? Burysinbuysrp ‘aarsnjour BIEL 92 SIGL S/Bah ay fo yova uw wophury paywy ay} wou pazsodwa yoy fo suoy, burmoyg *‘(panwywos) WY XIaVy, ON FUEL ECONOMY. 959 Apprnprx III, Memorandum upon the Skinningrove Process for the Production of Alcohol from Coke Oven Gas. Tux following is a brief outline of the process devised by Messrs. Bury and Ollander for the removal of ethylene from debenzolised coke oven gas and its conversion into ethyl alcohol. ) The average amount of olefines present in a debenzolised gas from a typical Durham coking coal is usually between 2'0 and 2°5 per cent. They consist chiefly of ethylene with small quantities of propylene and possibly other higher members of the series. The process for their removal from tie gas is based upon the well-known fact that ethylene is absorbed by concentrated sulphuric acid forming ethyl hydrogen sulphate, which may be subsequently hydrolysed by the dilution of the acid with water yielding ethyl alcohol and sulphuric acid. The sequence of the reactions concerned may be represented by the following equations :— C,H; (a) C,H,+H,S0,= H SO., C,H; (b) 80+ H,0 =C,H,OH+H,S0,. H The problem presented to the investigators was not only the determination of the conditions under which 2 per cent. of ethylene in an industrial gas can be rapidly absorbed by concentrated sulphuric acid so as to produce ethyl hydrogen sulphate exclusively, but also how the much smaller quantities of higher olefines contained in the gas can be removed from it prior to the desired absorption of ethylene. Laboratory experiments proved (i) that, although the absorption of ethylene by concentrated sulphuric acid proceeds far too slowly at ordinary temperatures, yet between 60° and 80° C., the time of contact required between the acid and coke oven gas, in order to ensure the absorption of 70 per cent. of its total ethylene content, need be no more than 2} minutes, and (ii) that under such conditions the only product formed is ethyl hydrogen sulphate. On the other hand, if the temperature be allowed to exceed 80°C. some decomposition occurs and ethyl ether is produced. The successful operation of such an absorption process on a large scale pre- supposes the elimination from the crude gas of tars, ammonia, naphthalene, and benzol hydrocarbons in the order named. At the Skinningrove Works the Otto direct process is employed for this purpose. The next step consists in the successive elimination from the cooled and debenzolised gas of (a) sulphuretted hydrogen, and (6) higher olefines than ethylene, together with most of its water vapour content. For the elimination of the sulphuretted hydrogen it is proposed to make use of the well-known reaction between sulphuretted hydrogen and sulphur dioxide gases :— 2H, +SO, ===]2H,0+38. The advantage of such a procedure is that it would not only dispense with the necessity of employing iron oxide purifiers (except perhaps as a final pre- caution), but it would also enable the small amount of sulphur dioxide arising from the reduction of the hot strong sulphuric acid during the later ethylene absorption process to be utilised. Propylene and other higher olefines are next removed by scrubbing the gas with an 80 per cent. sulphuric acid at the ordinary temperature in a tower on the counter-current principle, which also effects the removal of about 97 per cent. of its water vapour content. The resulting cooled and dried gas is then passed s 2 260 REPORTS ON THE STATE OF ScIENCE.—1920. through a ‘heat exchanger’ situated so near the ovens that its temperature cat be raised to between 60° and 80° ©. at the expense of some cf the sensible heat in the hot crude gas leaving the ovens, The strong acid (95 per cent.) used for the absorption is also pre-heated to the same temperature. The scrubbing process for the removal of ethylene is carried out on the counter-current prin- ciple, and the time of contact between the pre-heated gas and acid is 24 minutes, which is sufficient to effect absorption of 70 per cent. of the total ethylene present. The acid can be used until it has absorbed up to 5 per cent. of its weight of ethylene with the formation of a corresponding quantity of ethyl hydrogen sulphate. The strong acid from the ethylene absorption towers containing the ethyl hydrogen sulphate is next taken to a special form of distilling column where it meets a current of steam which dilutes the acid to about 75 per cent. strength and simultaneously hydrolyses the ethyl hydrogen sulphate forming ethyl alcohol and sulphuric acid. The heat produced during the dilution is sufficient to raise the temperature of the diluted acid to between 90° and 100° C., under which con- ditions the resulting alcohol distils over and is subsequently condensed, finally leaving the plant as a 95 per cent. alcohol. The diluted acid is finally pumped to the top of a Gaillard concentration tower where it is concentrated to a 95 per cent. strength, which is then used ever again for the absorption of ethylene. Any smal] quantity of sulphurous acid formed by the reducing action of the gases upon acids in the absorption tower is, during the dilution process, decomposed, and the resulting sulphur dioxide is (as aforesaid) utilised for the elimination of sulphuretted hydrogen from the debenzolised gas. From figures given in Messrs. Bury and Ollander’s paper (loc. cit.) the com- position of the debenzolised gas from a Durham coking coal, before and after the ates of the greater parts of its ethylene content in the manner proposed, is as follows :— Before After Carbon Dioxide , . P ’ - 2:0 2:08 Carbon Monoxide . ; é ; : 54 5°61 Ethylene, &c. . : ‘ ‘ 3 : 2:0 0°62 Methane . A : 5 : . 25:0 25°96 Hydrogen : { : : - - 50°0 61°91 Nitrogen and Water Vapour, &. . . 156 13°82 100:0 100:0 Before After Gross 5 ‘ 3 . 467°8 4589 Net * : «y ALD 402°8 W. A. Bone. EXPERIMENTS IN INHERITANCE OF COLOUR IN LEPIDOPTERA. 261 Old Red Sandstone Rocks at Rhynie, Aberdeenshire. Final Report of Committee (Dr. J. Horne, Chairman; Dr. W.. Mackin, Secre- tary; Dr. J. 8. Fuerr, Dr. W. T. Gorpon, Dr. G. Hickuine, Dr. R. Kwston, Dr. B. N. Peacu, Dr. D. M. 8S. Watson) appointed to excavate Critical Sections therein. Dr. W. T. Cauman and Mr. D. I. Scourfield have continued their examination of the microscopic sections of the plant-bearing cherts discovered by Dr. Mackie in the Old Red Sandstone at Rhynie, Aberdeenshire. The following Report on the results of their investigations has been furnished by Dr. Calman :—‘ A large number of sections and chips have now been studied by Mr. Scourfield, and drawings have been made of the more important remains. It has not been possible to discover any regularity in the way in which the specimens are distributed in the chert, or to correlate their presence with anything visible to the naked eye in hand specimens. Although the remains are of the most fragmentary kind, it has been possible to determine with fair certainty the more important characters of the body and limbs. We are now convinced that all the remains belong to a single species which is most nearly related to the Anostraca, although it differs in important morphological characters from the recent representatives of that order. It is hoped to discuss these remains at greater length in a memoir which is now in preparation. A few fragments of limbs and body-somites of a much larger Arthropod have been observed. There is some evidence to suggest that these may belong to a Diplopod, but it is not proposed to discuss them unless further material should be discovered.’ As sufficient material has been collected for further examination, the balance of the grant from the Royal Society has been returned. The Committee may now be discharged. Experiments in Inheritance of Colour in Lepidoptera.—First Report of Committee (Prof. W. Batrson, Chairman; Hon. H. Onstow, Secretary; Dr. F. A. Drxsy). Spilosoma mendica and var. rustica.—The white variety of the male is incom- pletely dominant. About 400 insects were raised from the following types of mating :—DR x RR, DD x DR, and DD x RR. Eggs were obtained from a number of pairings of DR x DR, which will emerge next year, 1921.. These, with the previous records, should be sufficient to elucidate the nature of the inheritance. Owing to the great colour variation of the F, generation, readings of the colour of each individual are being made with the ‘ Tintometer’ to show the colour distribution. Boarmia consortaria and var. consobrinaria.—About 200 insects were reared which confirmed the dominance of the melanic variety. The suggestion made in the J. of Genetics, Vol. IX. No. 4, March 1920, p. 339, that the intermediate variety is dominant to the type, was also confirmed. Ova were obtained which should show the relationship of the intermediate to the melanic variety next year. Hemerophila abruptaria and var. brunneata.—Ova were obtained from several pairs in order to see whether the melanic variety behaves as a simple Mendelian dominant. In the published experiments of Hamline and Harris there is a large excess of melanics in matings of the type DR x RR. Callimorpha dominula, and the yellow varietv.—About 700 insects were raised from these crosses, which completely confirm Bateson’s suggestion that the yellow form is recessive to the red. The insects reared will serve as material for an examination of the pigments. Zygena filipendule, and the yellow variety.—Larve were reared from several pairings between red and vellow varieties and from the F, generation. The larvee have not as yet nupated. Abraxas grossulariata and var. varleyata.—About 409 insects were reared from matings hetween the type and the melanic variety. Together with previous 262 REPORTS ON THE STATE OF SCIENCE.—1920, records, they fully confirm the recessiveness of the melanic variety. In the F, generation there appears to be a difference in the distribution of the black pigment between the two sexes. This is being investigated by means of camera lucida drawings of the F; generation, from which a calculation of the black areas may be obtained by means of a planimeter. A. grossulariata var. lacticolor and var. varleyata.—The combination of these two characters in the same zygote produces a new and very beautifully marked variety, named var. exquisita. If T=type, and t=varleyata, and if G=type, and g=Tlacticolor, then ¢ type=TTGG, 2 type=TTGg 3 varleyata= ttGG, 2 varleyata = ttGg 3 lacticolor = TTgg, 2 lacticolor = TT gg 6 exquisita = ttgg, 2 exquisita = ttgg Therefore TtGgxTtGg should give a 9:3:3:1 ratio of type, varleyata, lacticolor and exquisita, but, owing to the spurious allelomorphism in the F, generation, the sex ratios will not be normal. Experiments are being made to test this. Up to the present, though the numbers are small, owing to the unfortunate incidence of disease, an excess of type and varleyata individuals is indicated. It is hoped, if possible, to complete the experiments indicated above next year. It is also suggested that, in the event of material being procurable from Germany, experiments might be initiated to elucidate the inheritance of Aglia tau and its var. lugens. Committee to co-operate with Local Committees in Excavations on Roman Sites in Britain.—(Sir W. Ripeeway, Chairman; Mr. H. J. E. Psaxe, Secretary; Dr. T. Asupy, Mr. WinLoucHBy Garpner, Prof. J. L. Myrss). Owrne to the war the Committee has been in suspense since 1914, when all excavations in the Hill Fort in Kinmel Park, which was being explored by the Abergele Antiquarian Association and the Cambrian Archeological Association in co-operation with this Committee, came to an end. Although the Committee had not been revived in 1919, and therefore no srant was available, Mr. Willoughby Gardner reopened his investigations in November 1919, and has supplied the Committee with a detailed report of them. ‘The Committee asks to be reappointed. Abstract of Report on Further Excavations in Dinorben, the Ancient Hill-Fort in Parch-y-Meirch Wood, Kinmel Park, Abergele, N. Wales, during 1920. By WitLoucHpy GARDNER, F.S.A. THE excavations in this native hill-fort (see Reports of the British Associa- tion, 1912, 1913, and 1915) were reonened in November 1919. A first objective was the further investigation of the huge main rampart. Attention was directed to the cutting through it on the S.W., where archeological ‘floors’ and con- structions belonging to two occupations,-A and B, had been previously dis- covered, and where the top course of a wall belonging to an earlier construction had been found beneath the lower Floor B. Before we could excavate this it was necessary to widen our cutting considerably, thus enabling us to examine further areas of Floors A and B. In the uppermost, A, more relics of the fourth century were found. Below it the revetting wall excavated in 1914 was ON FURTHER EXCAVATIONS IN DINORBEN, 263 found to be built upon an earthen surface marking a fresh floor between Floors A and B. Upon this lay bones, pot-boilers, &c., but no pottery or coins, differentiating it therefore from Floor A and causing us to name it Floor A2. The core of the rampart behind this wall consisted of rubble stones in its lower half and of layers of clay above. This clay had been visibly laid on wet, and had afterwards dried hard like cement, so as to give a foundation for any stone structure, such as a parapet wall, which is indicated by surviving stones seen here and there along the crest of the rampart. A further length of the back revetting wall of the rampart belonging to the earlier Floor B was next uncovered. The rampart consisted of rubble stones and was about 15 ft. thick, but its outer side and facing wall were ruined and missing. It was built upon a similar layer of hardened clay 4 ft. thick. Behind it Floor B, of dark soil 3 ft. thick and gradually shallowing. stretched towards the interior of the hill-fort. Upon this were found bones of domestic animals, much charcoal, broken pot-boilers, a pounding stone, sawn antlers, a deer-horn toggle, and an iron knife-blade. About 20 ft. from the wall a mass of burnt limestones mixed with baked red soil and much charred wood like burnt timbers was unearthed. also several stone-lined post-holes. Apparently this was the ruin of a stone-and-timber building destroyed in some great con- flagration, such as previouslv observed in and near the earliest S.E. entrance. Having removed Floor B, it was possible to investigate the wall-top found below it in 1914. This was followed downwards till a ruined dry masonry facing wall, still standing in one part 5 ft. high and backed with an 8 ft. thick core of large stones and rubble, wag revealed to view. This newly discovered rampart, was erected upon a floor surface of dark soil 6 in. thick, which we designated Floor C. It would appear to be a portion of the earliest defence constructed upon the site. Keen search was therefore made for relics here. The floor was followed up as far as practicable at the bottom of our deep cutting. revealing charcoal, pot-boilers, broken bones of domestic animals. and sling stones, but unfortunately nothing definitely dateable. In front of the wall the ground was piled high with the débris of the upper half of the thrown-down rampart, which was once, apparently. about 10 ft. high. Search was next made for a ditch defending this ramnart. The hill slope was followed beneath the fallen ruins and then beneath lavers of clay for a horizontal distance of 23 ft. from the wall hefore one was found. But here a section of a rock-cut ditch 6 ft. wide and 5 ft. deep was dug out. It was filled with rubble mixed with a few wall-facing stones, with a 1 ft. laver of dark soil half-way down containing animal bones and a. portion of an antler probably used as a pick. Tt was covered at the bottom with 6 in. of silting, As the second and third onlv of the three earth-cnt ditches beloncine to Floor A seen along the S. side of the hill-fort were visible. though nearly filled with débris, along the S.W. side. our cutting was extended outwards to search for the first. This was found buried deep under silting and filled with stony debris from the partial demolition of the Jatest main rampart. Tt was rock- eut. 15 ft. wide and 7 ft. deep. and had but a thin layer of silting on the hottom. The second and third ditches were then fnllv excavated. the second heing filled with stony débris and the third with soil and a few fallen stones. No relics were found. Turnine from the S.W cntting. renewed attention was raid to the defences nvon the §S. side of the hill-fort. Here a cutting had already been made across the upper portion of the creat main ramnart and the three onter earth-cut ditches had been excavated. The first ditch had been found to be filled with clean quarried rubble stones mixed with wall-facing stones—the thrown-down débris of a parapet which once stood unon the crest of the rammart and which was approximately contemporaneous with the fonrth-century Floor A. In order to excavate deener down, this cutting also had to be widened, at a cost of much exnensive Jabour- hut bv this widening. additional knowledce of the periods of occunation of the hill-fort was obtained. Here. as in the S.W. cutting. 2 floor and construction, A2. were found intermediate between Floors A and R. A further lencth of the hack revetting wall of the rampart belonging to Floor B was also uncovered, built upon a similar foundation of 264 REPORTS ON THE STATE OF SCIENCE.—1920. hardened clay. The core of this rampart was composed in places of rubble and in places of clay, probably the work of different gangs of labourers. Here there does not appear to be a floor in actual contact with the wall, but there was one four feet below it. This, Floor B, was first visible as a thin layer of soil covering the surface of a former clay rampart thrown up rather 8. of the crest of the present one. It was followed up towards the N., 4 ft, below the bottom of the above-named wall, 2 ft. below Floor A2, over a low bank of made clay, till, at length, it became indistinguishable from Floor A. Along its course animal bones, charcoal, pot-boilers, and the cut shank-bone of an ox with four holes drilled in it (probably used for weaving) were found. Con- siderable stony remains, apparently of buildings destroyed by fire, as in the S.W. section, were also encountered. These ruing will require working out by exposure of larger areas. Floor C was next sought for in this cutting by driving in trenches at increasing depths from the southern slope of the rampart. The floor, which was shown to be a surface of human habitation by finds of broken animal bones and charcoal, was finally discovered at a level of 27 ft. below the present crest. It was followed up for a distance of 32 ft., when the cutting became too dangerous to continue. The absence of a ditch in this floor in a similar posi- tion to that found in the S.W. cutting was noticeable. We next excavated te reach this floor from the northern side of the rampart. Digging down below Floor B, we came upon the core of a stone rampart, with several massive wall- facing stones in situ in front of it, erected upon a demonstrable continuation of Floor C. This rampart had been visibly thrown down almost to its founda- tions and its stones filled an earth-cut ditch 10 ft. wide which was subsequently discovered a few feet in front of it. We cleared out most of these stones, finding animal bones, pot-boilers, and an antler among them, and measured the V-shaped sides of the ditch as we proceeded. But the dangerous nature of the cutting unfortunately prevented our reaching the bottom, 7 ft. deep, except by probing ; a cracking side obliged us to wifhdraw—just before a fall of earth commenced. There could be litfle doubt that this ruined rampart and ditch were portions of the earliest defences erected upon the hill-side. Strange to say, however, the rampart did not’here rest upon the original ground. Beneath it there was a layer, 6 in. to 12 in. thick, composed of broken stones—at first sight much like the metalling of a road. But inspection showed that they were fractured by heat and were such as were usually recognised as pot-boilers. Upon and among these stones numerous bones of domestic animals were found, many broken’ for marrow, as well as much charcoal. Altogether this layer, which we uncovered for some four square yards, had all the appearance of a ‘cooking hearth,’ except for the absence of an adjacent water-supply. This ‘hearth’ must have existed on the hili-side before rampart C was thrown up. While the main rampart was being excavated, about 85 square yards of the top Floor A were explored in ‘the interior of the stronghold and many relics found which were unmistakably dated by coins found alongside. These relics, when worked out, will afford valuable material for the classification of the later Romano-British pottery, or at any rate of such common wares as were spread among native hill tribes by traders at that time. Although marked progress has been made and much hag been learned as the result of this year’s work, the area uncovered of the deeper Floors B and C is as yet very limited. It is most desirable that larger surfaces of both should be excavated. Then only will it be possible to join up the layers of occupation found in the ram- parts with the roadways and constructions discovered in former years in the 8.E. entrances. Many promising sites spread over the 5} acres of the hill- fort are also ‘calling out’ for exploration. We look forward to continuing work at Dinorben next year. ON THE DISTRIBUTION OF BRONZE AGE IMPLEMENTS. 265 Exploration of the Paleolithic Site known as La Cotte de St. Brelade, Jersey.—Report of the Committee (Dr. R. R. Marert, Chairman ; Mr. G. F. B. pr Grucny, Secretary; Dr. C. ANprEws, Professor A. Kerrn, Mr. H. Baurovur, and Colonel R. GarpNer Warton). Dourine August and September 1919 and again in April 1920 excavation was continued, mostly by the aid of amateur labour, as funds were low. A trench was driven along the W. wall of the cave some 10 ft. below the bottom of the paleolithic floor. Nothing, however, came to light here except a curious peaty deposit in two layers, each about a foot thick, and separated by a stratum of sandy clay; nor was bedrock anywhere reached. On the other hand, just out- side the cave-entrance a sloping platform was discovered where flint-knapping must once have been energetically carried on, as was proved by the presence of nearly 1,000 flint fragments, including a few well-finished instruments. Here, among other bone, a tooth of the cave bear (Ursus spelceus) was found. Strangely enough, this species had not hitherto been reported from this site. At a higher level in the ravine adjoining the cave-entrance is a rodent-bed, differing slightly in its composition from the rodent-bed within the cave. This year’s collection consists, according to Mr. Hinton’s analysis, of two species only, viz., Dicrostonyx henseli 85.3 per cent., and Microtus anglicus 14.7 per cent. Associated with this bed was a bone determined by Dr. Andrews as undoubtedly belonging to the Great Auk (Alca impennis). This also is a new record for the cave, and it is interesting to find this species so far South. The Distribution of Bronze Age Implements.—Interim Report of the Committee (Professor J. L. Myres, Chairman; Mr. Haroip PEAKE, Secretary; Dr. G. A. AupEn, Mr, H. Baurour, Mr. L. H. D. Buxron, Mr. 0. G. §. Crawrorp, Sir W. Boyp Dawkins, Professor H. J. Frnurn, Mr. G. A. Garrirr, Dr. RB. R. Marerv, Sir C. H. Reap, and Sir W. RipGEeway). THE Committee was first appointed in 1913, and decided that before any con- clusions could be drawn as to the Distribution of Bronze Age Implements it was necessary to compile an illustrated card catalogue of all the metal objects of the Bronze Age found in the British Isles. This task was begun in July 1914, but during the war it was not possible to progress rapidly with the work. The Committee has had throughout the assistance of Dr. H. S. Harrison, representing the Royal Anthropological Institute; Lord Abercromby, represent- ing the Society of Antiquaries of Scotland; and Mr. E. C. R. Armstrong, repre- senting the Royal Irish Academy. The method employed is to make full-size drawings of the objects, with one or two sections, on thin paper, and to note full particulars as to the discovery and subsequent history of each object, references to published accounts, as well as its dimensions, weight, condition, and associations; these particulars were then transferred to cards, 10 in. by 7 in., by the secretary. During the years of war a number of such drawings were made by voluntary helpers, and about a thousand cards were completed. It was decided in 1919 that if the work was to progress more rapidly the Committee would require the assistance of paid workers. The Association made a grant of 100/., with permission to raise additional funds in its name. No agin appeal has yet been made for funds, but the money received to date as been: British Association . P : : £100 0 0 Robert Mond, Esq. . ; : . £30 0 0 G. A. Garfitt, Esq. . , ‘ - 1010 0 Mrs. Hookham ; P ; - on 0.0 Royal Irish Academy “s ..0),0. 0 — 50 10 0 £150 10 0 Tho thanks of the Committee are due to these helpers for their support. 966 REPORTS ON THE SCATE OF SCIENCE.—1920. In May 1920 a draughtsman was engaged and trained, and some work was put out at piece rates to another draughtsman, so that by the end of June the cards completed numbered 1,649, while about 1,000 additional drawings still remained to be copied. Several Curators of Museums have kindly supplied the drawings of the objects in their custody. and many more have undertaken to do this in the near future, so that the work of the draughtsman will be mainly confined to filling in the cards and visiting small museums and collections. On June 30 the expenditure amounted to 727. 5s., and the balance available will pay for the draughtsman until the end of Sentember. It is estimated that about 2007. a year will be required to pay for the one draughtsman regularlv employed, together with his travelling expenses, and the purchase of additional material. Electromotive Phenomena in Plants.—Report of Committee (Dr. A. D. Water, Chairman; Mrs. Warr, Secretary; Dr. F. O’B. Exutson, Prof. J. B. Farmer). Durine the last year we have taken a considerable number of observations on the growth of plants in the garden and of their amputated parts in the laboratory. We have examined into the relative physiological activity of growing and non-growing zones as shown by their electrical response to electrical excitation (blaze-currents).1. The disposition of apparatus has been as described in previous publications and is summarised in the diagram overleaf. Observations have for the most part been carried out upon Iris germanica during the months of April, May, and June. The following is a representative experiment :— Tris in its natural habitat in a flower bed with S.W. aspect. Leaf. 25 cm. long, marked by Indian ink into 50 equal parts on April 24. The marked leaf was examined from time to time and the markings remained apparently unaltered in length, but raised en masse with the growth of the leaf which was measured and shown at the Royal Society on May 13 the lowest mark was raised 5 cm.—.e.. the growth had been exclusivelv basal. A similar leaf, about 20 cm. long, was led off to the galvanometer from its base close to the rhizome and from a point of the leaf 5 cm. higher up; it exhibited a current of rest directed in the leaf from base towards apex. In response to a strong break induction shock. B to A (7.e., ascendine\, a, strong blaze-current was aroused in the same direction B to A (post-anndic homodrome action current indicative of predominant change at B). A similar. but less marked, response in the same direction, B to A, was aroused by a strong induction shock passed through the leaf from A to B (post-kathodic antidrome response). Strong alternating induction currents were now passed through the A B nortion of the leaf for a period of one minute in order to effect its electrocution. The blaze test bv a single induction shock first in the ascending then in the descending direction failed to aronse anv marked resnonse: in each case the onlv visible effect was a small deflection antidrome to the exciting current—t.e.. in the direction of nolarisation. The suppression of the blaze-current by electro- cution can be definitive or temporarv, according to strength. Conclusion.—I. The basal zone of the Tris leaf, in which alone active growth is in nrogress. is electrically active (zincative) in relation to parts where active growth has ceased. II. The zone of active growth is aroused to greater physiological activity (i.e., is more zincable) than are parts in which growth is not proceeding. 1 The rationale of ‘blaze-currents’ as a sign of life has heen set forth in several nrevious communications and is summarised in the following : Lectures on the Signs of Life from their Rlectrical Aspect (John Murrav, London. 1903) : Physiology the Servant of Medicine (University of London Press, 1910). British Association, 90th Report, Cardiff, 1920. | (Puate I. 4m MM Diagram of the circuit required for the systematic observation of the blaze- currents of plants. B A are the unpolarisable electrodes by which the plant currents are led off to the galvanometer G. Any accidental current or current of injury of the plant is neutralised by the compensator. The wires from the compensator are connected with the two ends of the three-plug key. A single induction shock of given strength and direction can be short-circuited or not by a plug at the first plug-hole. The plant can be short-circuited or not at the second plug-hole. The galvanometer can be short-circuited or not at the third plug-hole. Procedure.—Any accidental current or current of injury of the plant is neutralised (and measured) by adjustments on the dials of the compensator. The galvanometer is short-circuited at the third plug-hole. A break induction shock of given strength and direction is sent through the plant by (closing and) opening a contact-key in the primary circuit of the induction coik (during closure of this key the secondary coil is short-circuited at the first plug-hole to cut off the make shock from the plant). Immediately after the break shock has passed through the plant, the galvanometer is unplugged at the third hole; the blaze-current aroused by the previous break induction shock now causes deflection of the galvanometer. the voltage of a deflection is ascertained by comparison with the deflection given by 0.01 volt from the compensator. The resistance in circuit is ascertained by comparison with the deflection of 0.01 volt through 1,000,000 ohms. Illustrating ‘ Electromotive Phenomena in Plants.’ {To face page 266. Sa eT ae a pie SF e ( BF 3 s ace cp a %y a evi ieee” ON MUSEUMS IN RELATION TO EDUCATION. 267 Museums in Relation to Education.—Final Report of Committee (Pro- fessor J. A. GREEN, Chairman; Mr. H. Bouton and Dr. J. A. Cuuss, Secretaries; Dr. F. A. Barner, Rev. H. Browns, Mr. C. A. Buckmaster, Professor E. J. Ganwoop, Dr. A. C. Happon, Dr. H. §. Harrison, Mr. M. D. Huu, Dr. W. E. Hoyts, Sir H. Miers, Professor P. Newserry, Mr. H. R. Ratuzons, Dr. W. M. TATTERSALL, Sir Ricnarp Trempte, Mr. H. Hamsuaw Tuomas, Professor F. E. Wetss, and Dr. JEss1z WHITE). Tue Committee was formed at the Birmingham Meeting of the British Association in 1913, with the following terms of reference: ‘To examine, inquire into, and report on the character, work, and maintenance of Museums, with a view to their organisation and development as institutions for Education and Research; and especially to inquire into the requirements of schools.’ The work was carried on energetically for four years, and numerous subsidiary reports drawn up by sub-committees were considered. The increasing gravity of war conditions and the absence of members upon various war activities suspended further work. Recent Legislation. Museums and Advanced Students. The Functions of Museums. Museums and Classical Education and Museums in 1914. the Humanities. Museums in Relation to the Genera] | Staffing of Museums. Public. Overseas Museums. Museums and Schools. Manchester Scheme. Recent Legislation. The Education Act passed in 1918. and the more recent Libraries Act of 1919, have profoundly modified the position of Museums in relation to Education. and definite lines of development have been foreshadowed by the Reports of the Committee on Adult Education of the Ministry of Reconstruction, and by the issue of ‘Draft Suggestions for the Arrangement of Schemes under the Education Act of 1918,’ by the Board of Education. These changes have been taken into account in the present Report, and pare rendered necessary a revision of some parts of the work previously one. 1. The Education Act of 1918 made it possible for local Education Committees to seek the assistance of Museums in the furtherance of local schemes of educational development. This was emphasised in 1919 by the ‘ Draft Suggestions for the Arrangement of Schemes under the Education Act of 1918,’ issued by the Board of Education. These Suggestions indicate the desirability of arrangements for ‘securing and developing the educational uses of Museums and Libraries,’ and for ‘ developing the educational activities of local Literary, Historical, Archeological, Scientific, Musical. Artistic. and Dramatic Associations.’ In 1918 the Ministry of Reconstruction presented to Parliament an ‘ Interim Report of the Committee on Adult Education upon the Industrial and Social Conditions in Relation to Education.’ The questions raised in that Report were more fully reported upon in a ‘Third Interim Report’ presented to Parliament in 1919. In a still later Report the © nmittee on Adult Education considered the conditions and work of Museums, and advanced the suggestion that these 968 REPORTS ON THE STATE OF SCIENCE.—1920. institutions should, together with Public Libraries, be definitely included in any scheme of education for a local area in England and Wales, and that these institutions should be taken into account in State grants allotted to the local authorities. : It was further suggested that, under the powers and duties of the Local Government Board, Libraries and Museums should be transferred forthwith to the Board of Education by an Order in Council. The Committee on Adult Education did not seek the advice of this Committee, or of the Museums Association, and unfortunately their recommendations for the transference of Museums and Libraries to the local Education Authority proved unacceptable to both the Museums Association and the Library Associa- tion. The Public Libraries Act, which received the Royal Assent in December 1919, makes it possible for the change to be brought about locally at any time. The same Act also abrogates the Museums and Gymnasiums Act of 1891. under which a rate of 3d. in the £ might be levied by a local authority for the maintenance of Museums. A County or Town Council may constitute itself as the Library Authority, and bring all public Museums under its control, though it is in the discretion of this authority to appoint a separate committee for Museum management. The amount of the rate for maintenance for any year is to be decided by the Library Authority, no limit being fixed. Further, it is provided that a county which has adopted the Libraries Acts may borrow for the purpose of these Acts, as for the purpose of the Local Governments Acts, 1888; sixty years is the time period laid down for repayment of loans. The Libraries Act. 1919, thus provides for the adequate maintenance of Museums, if local authorities choose to exercise their powers. It also enables the raising of capital sums for buildings and fittings. Furthermore, official recognition has now been given to the Museum as an auxiliary factor in public education, but we desire at once to point out that the recommendations of the Committee on Adult Education for the transference of Museums by an Order in Council to the control of the Board of Education may, if pressed too far, seriously prejudice the functions of Museums as conservators of material and centres of research. The Functions of Museums. Before considering the questions specially raised in the terms of reference to the Cemmittee, and in order to clarify the subject, it seems advantageous to state what seem to the Committee to be the proper functions of a Museum. Museums are of many kinds. There are institutions which rank as Museums in one sense, yet have no collections; such is the Whitechapel Art Gallery, which educates through loan exhibitions. There is at least one Museum in the United States which has only a director’s office, since all its possessions are always out on loan. The Circulating Department of the Victoria and Albert Museum carries out the same idea on a larger scale; but by its historical development, and in the general acceptation of the term, a Museum is a place where objects appealing by their form, not by the written word, are preserved for reference and study. The aims and functions of this last kind of Museum are :— 1. Collection of works of Nature and of man. Collecting may be through work in the field, through purchase, and through donations. The first of these is the most valuable as assuring accurate data of provenance. Obviously, the function of collecting must precede all others. 2. Preservation of material thus collected. Much of this is the irreplaceable groundwork of human knowledge, and ought to be safeguarded at all costs. This is the necessary second function. 3. Study of the collected objects. This is the research side of Museum work, and, whether carried out by the staff (as in large measure it should and must be) or by specialists under the direction of the staff, it must be prosecuted if Museums are to fulfil their highest function, which is the advancement of Science. Art, and Industry. 4. Classification of Museum material, so that each specimen is readily accessible to future students, ON MUSEUMS IN RELATION TO EDUCATION. 269 Functions 3 and 4 are the necessary preliminary to those which follow. 5. Publication of the results achieved and of guides to the contents of the Museum. (a) By printed memoirs, catalogues, summary lists, and guide-books. (b) By the exhibition of specially selected series of specimens in an arrange- ment designed to bring out some definite information, and provided with labels written for the same end. (c) By the loan of material to other Museums, exhibition galleries, schools, and similar institutions. (d) By lectures in or outside the Museum, in the galleries or in a lecture- room, on the ordinary exhibited series, or on specimens selected ad hoc. Whereas (a) is largely connected with the function of research (3), this in part, and sections (b), (c), (d) entirely, constitute the educational side ot Museum work, The greater the weight attached to this function, the greater the need to realise that it must be based on those which precede, ; Though implicit in the above statement, certain points require emphasis for our present purpose. The exhibition of all material is undesirable. Special material liable to loss or damage (e.g., from light) should be withheld from exhibition. Access to exhibition cases by scholars is undesirable; if specimens are to be handied they must form part of a special teaching series. pen collections for scholastic purposes should consist of easily replaceable material. Museums in 1914. A. Lstablishment.—A fair idea of the general character of Museums as they existed in 1914 was obtained by the issue of a lengthy questionnaire, to which the authorities of one hundred and thirty-four Museums replied. Two of these Museums were privately owned, twenty were the property of Institutions or Societies, and nineteen belonged to Universities, Colleges, and the large Public Schools. Ninety-two were municipally owned. The governing authori- ties were even more diverse than the ownership, and it seems probable that many Museums, though more or less public in character, will remain unaffected by recent legislation. The replies to the questionnaire showed that Museums had arisen in various fashion ; possessed widely diverse governing bodies; and were supported in a great variety of ways. Purpose was as diverse as origin and control. Those owned by municipalities had, however, gradually moved towards a common type and common standard, owing largely to the work of the Museums Association. Governing authorities consist of elected Councils, Museum Committees, Scientific Societies, Library Committees, Members of Town and Corporation Councils, Boards of Directors, Subscribers, University Senates, &c. Sixty-four were supported by Borough and District funds or by a Library rate, thirteen had voluntary contributions, twenty-one had subscribers, eleven had invested funds and donations, ten received admission fees, and two were supported by Societies. Fourteen received funds from a University chest, a College, or a School fund. Annual income varied from 6/. to 11,000/., the greater number having an income of less than 2,0007. Notwithstanding lack of income, most Museums opened every day, and forty opened on Sundays. The value of the collections in public Museums is probably beyond calculation, and the buildings themselves represent a very large capital value. The following figures are indicative of the actual position: Three Museums have buildings of a capital value of from 200,0007. to 300,0007. each, two from 100,000/. to 200,0007., nine from 50,0007. to 100,000/., and twelve from 10,0007. to 50,000/. The collections of oe ae are valued at 320,000/.; another, 250,000/.; four at 100,000/. to ,000/. The most widely represented sections of Museum work are: Zoology, 80 Museums; Geoloov. 75; Archeology and Antiquities, 60; Fine Arts, 40; 270 REPORTS ON THE STATE OF SCIENCE.—1920. Botany, 35; Painting and Engraving, 30; Engineering, Geography, Commerce, Chemistry, Physiology, Physics, and Astronomy are slightly represented im existing collections. It may also be pointed out that many towns of considerable size are not provided with Museums. Possibly recent legislation may find its best fruits in the filling up of these gaps. B. Museums and Schools.—The Committee’s inquiries show that Museums collectively have, on their own initiative, anticipated in a striking way many of the requirements considered necessary for the needs of schools, a fact which illustrates their readiness to co-operate with the educational developments fore- shadowed by the Education Act of 1918. It shows also that educational work on the side of Museums is possible without injury to their other functions. Given an adequate staff and an increased maintenance income, Museum curators, in conjunction with the teachers, will be able to work out suitable methods for the educational use of their collections. The experience so far gained goes far to show that the training and opportunities of teachers do not enable them to realise for themselves the possibilities of Museum collections as aids to education. Many British Museums have for years encouraged visits from schools and classes, either under the leadership of their teachers or the guidance of a member of the Museum staff. In some cases these visits have been systematised by arrangement with the educational authorities, and the Museum collections have been studied according to a pre-arranged plan. A great development of this system was tried with success in Salford and Manchester under special conditions arising in connection with the late war. (See page 279 et seq.) Other Museums have established systematic courses of lessons to school classes upon a plan jointly agreed upon by the Education and Museum authorities. Sheffield has for years maintained circulating collections of special groups of objects for schools. Replies to the Committee’s questionnaire showed that for many years similar work of a less systematic kind had been carried on in many centres. They showed that :— 1. Instruction was given by the teachers alone in twenty-eight Museums. 2. Instruction was given mainly by teachers, the curators sometimes assisting, in twenty-four Museums. 3. Instruction was given by the Museum staff in sixteen Museums. 4, Sketching parties, classes, and individual students from Schools of Art were regular visitors in most Museums. The experience gained by the use of Museums in education in the United States is so extensive, and has been so thoroughly tested, that it is desirable in any educational plans for the use of British Museums that this experience, the methods adopted, and the nature and extent of the work, should be carefully considered. (See page 277 et seq.) C. Museum Guides.—From returns supplied to the Committee, only two Museums, other than National, had established official guides; one was a rate- supported Museum, the other owned by a Society. That the need was recognised, and met as far as possible, is shown by the fact that seventy-four Museums stated that arrangements exist whereby the curator and his staff give demonstrations to special parties. Financial stringency and inadequate staffs alone had prevented this work from becoming a well-developed branch of Museum work. It is eminently desirable that means should be available either for the employment of special officers for this duty, or for enlarged staffs, if the time of curators is not to be unduly taken up by work which is not the most important of their duties. Museums in Relation to the General Public, The special work of this Committee concerns the Museum as a factor in education. The words ‘General Public’ are used in the widest sense. We propose, therefore, to consider first the educational work the Museum may do for the general public. The term covers a wide range of needs. It represents the vast majority of visitors to the public Museums; we may safely regard them ON MUSEUMS IN RELATION TO EDUCATION, 271 as having little or no special knowledge, and a very large proportion of them enter the Museum without any specific purpose. They are just ‘looking round.’ For such people the Museum may do great service, if it sets about it in the right way. By some means or other it should strive to put them en rapport with the purpose of the Museum. This purpose, for them at least, is to reveal one aspect or other of an ordered universe to people largely uninstructed. These casual visitors are easily overwhelmed by multiplicity of specimens and of words. The first essential is a definite scheme, carried out with simplicity, boldness, and clearness. Elaborate labels, completely logical series, and involved argument do not assist them. What the scheme is to be, and its detailed carrying out, must vary with the locality and circumstances. We may, however, suggest that every Museum should illustrate fully in its exhibition cases the local fauna and flora, geology, archeology, history, industries, and art. ‘The local natural history should be treated from an ecological point of view, so that the visitor may not only realise what is to be found locally, but will learn under what conditions it is found, the associations of which it forms a part, why certain animals and plants are found locally, and why others are not, and the relations of the fauna and flora. to the local geology. It is also important that the general public should realise the changes im the local fauna and flora which have been brought about by the growth of civilised communities and the activities of the human race. Every locality will provide instances of this tact, and every Museum should make a point of illustrating it for the locality which it serves. Where towns or localities in which Museums are situated possess special industries, such industries should be illustrated in the local Museum, both historically, by showing the growth and development of the industry in the town, and the products of that industry at various periods; and technically, by illustrating the various processes of manufacture and technique. The Museum should possess a representative collection of present-day industrial products of the locality, and, by keeping that up to date, the industrial history of the district will always remain clear. Similarly, the Public Health work of the district should be adequately illustrated in the Museum. The general public should look to the local Museum for information on all the various activities going on around them. If they are sure of that, their powers of observation will be stimulated. ‘They will go to the Museum to learn what ought to be seen, its why and its wherefore. If they see anything new, they will go to the Museum for information. Both Museum and public will thus be mutually benefited. It follows that in Museums reference collections of everything local should be as complete as possible, not necessarily exhibited, but so housed as to be readily available for the use of those who desire to consult them. By this means it is possible to turn the general public into real students, which is the ultimate aim of this branch of Museum work. The Reference Library attached to the Museum should be accessible to visitors, who should be encouraged to use it. The library might also make a special feature of local publications and all books dealing with the locality from any point of view. Reports of local societies and organisations should be made a strong feature. A Museum which remains entirely local misses something of high educative importance. To interpret the local fauna and flora rightly means an acquaintance with a wider range of facts, and the Museum should try to provide that wider setting which will give meaning to local phenomena. in providing this wider range of specimens, the well-conducted Museum will in its total form resemble an iceberg of which only one-tenth appears above the water-line. The cases will be suggestive and directive, not complete and confusing. Everybody should ow, however, that there is much more material in the recesses of the Museum than is shown in the public galleries, and that this is quite accessible to alk who have an intellectual need which it can satisfy. Reference collections should be as complete as possible within the range they cover. Better a narrow range completely represented than a wide one with many gaps. Index collections are necessary in all large Museums, and smaller Museums might well arrange their cases on the principle of the Index collection. 272 REPORTS ON THE STATE OF SCIENCE.—1920. Temporary exhibitions are a means of attracting the attention of the general public. They offer an opportunity of driving home a particular lesson, and suggest a wide field of activity for the living direction of a Museum. Similarly, the frequent changing of exhibits in the cases will add to the attraction, though aimlessness must be avoided here as everywhere in Museum work. Crowded cases of birds, which are not merely inartistic and ugly, but are also wholly ineffective, are characteristic features of many Museums. Their contents ought to be re-arranged on some definite principle. In many cases, no doubt, this overcrowding is due to the absence of store-rooms in the building. é The general public may be helped by the Museum authorities in a variety of ways :— 1. For general use a Guide, simply written and dealing with the collections in the order in which they should be viewed, is best. Handbooks to special sections are also useful, and often command a ready sale. Publications should be as cheap as possible, and, if sold at some loss, the sale is merely carrying a step further the provision of free specimens, free labels, and free lectures. 2. The part played by an official guide in a small Museum will probably differ considerably from that of his colleague in a large Museum. It may be found that the ‘conducted party’ is not easily got together in a small Museum, and that the services of the guide will not be greatly in request. For societies and other special parties he will be useful, and also for informal demonstrations. Schools will make use of him, but this is not always necessary, as the teachers themselves may be competent. 3. Lectures play an important part in attracting visitors, in developing interest in the control of the Museum, and in stimulating further study. A lecture-room should be provided in every Museum. Museums and Schools. The services of the Museum to the school must vary greatly according to local circumstances. A Museum can never take the place of field work in Nature Study, or Geography, nor can the exhibition of historical relics, models and the like be more than a pale substitute for visits to historical sites, buildings, &c., when these are accessible, though an enterprising curator may gather within walls significant fragments from the past, and by careful arrangement do much to help the young to build up pictures of the old times which will make history something more than a mere matter of words. The success of the Museum as an educative agency depends very much upon the skill with which it suggests a world of reality outside the Museum itself. The difficulty of managing this varies according to the experience of the visitor. The aimless wanderer whose curiosity may be awakened and directed by good Museum. arrangement is not, howeyer, here in question. The schoolboy is, ex hypothesi, under personal guidance or under the guidance of ideas and problems which the schoolmaster has inspired. How can the Museum encourage and assist him? We have already noted activities in this direction actually in existence in 1914, and the Manchester experiment is a later development. Much may also be learned from the practice of the Overseas Museums. The Committee's inquiries have led to the following conclusions :— There are, broadly speaking, two types of use to which the Museum lends itself. 1. Its collections may be used to illustrate a particular course of instruction and reading which is part of the school curriculum. A class which is studying Australia may visit the Museum to see specimens of its fauna and its minerals, and to study the ethnographical collection. Here the Museum renders ancillary service of the highest value. A close acquaintance with the school curricula in the locality seems desirable, and temporary exhibitions might be arranged if co-operation between school and Museum eervices could be secured. 2. On the other hand, the Museum collection as such may be an object of study. The work will be very different in character. It centres in the Museum which is, as it were, a textbook in material form, and the instruction aims at making _ this material intelligible. It is clear that for work of this kind the ordinary logical arrangement of the Museum cases will in many ways need revision. Teaching must take its start from the pupils’ own minds, and select its material ON MUSEUMS IN RELATION TO EDUCATION. 273 from the point of view of its relation to the world they know. It is the psychological order that must be followed, and the logical arrangement will determine the end, not the beginning, of the course, lt is precisely through the difficulties which this involves that the trained teacher is more likely to be successful in this type of work than the curator or his assistant, but the average teacher has neither the knowledge of the subject ner the command of the Museum’s resources which are essential. The Manchester device has much to teach us in this regard. Whether or not a particular Museum is suited to this kind of work will depend partly upon its contents and its buildings. A lecture-room equipped with lantern, with various devices for showing specimens at the lecture table, and with tables rather than sloping desks, in order that specimens may be handled by the class, seems absolutely essential. System and purpose must govern the use of the Museum by schools. The aimless wanderings of groups of children about the galleries is sheer dissipation, a nuisance to the staff and to the public. Enough has been said to indicate the lines, which may be followed. A keen teacher will find something helpful even in a dead Museum, and a living Museum will lay itself out to seek the advice and help of teachers in the attempt to play its part in the educational service of the locality. We may especially note the possibilities, which have so far been only slightly developed, in the provision of circulating sets of illustrative objects designed for school use. It is essential, however, that such sets should avoid the error of over-systematisation, especially for use in primary: schools. The contents of the cases should be determined by the point of view of those for whom they are designed, and not by a specialist who knows his subject ag a systematised body of krowledge, but has no conception of what his specimens will mean to a person who is both young and uninstructed. Museums in Relation to the Advanced Student. This question has to be considered from two distinct, and at times conflicting, “points of view—viz., the needs of the particular class of student; and the needs of the Museum and its staff in relation to other calls. These students for the present purpose may be divided into :— 1. Research Students. | 3. Private Students. 2. University Students. / 4. Collectors. The number of Museums which can render material aid to the advanced student is limited, although it must not be forgotten that even the smallest Museum usually, possesses one or more objects of scientific or artistic value. The Redlands made upon the Museum staff by the advanced student are serious. Not only is a great amount of time consumed in providing material, but almost invariably calls are made for enlightenment upon points which arise in the course of his inquiry; he needs frequently to discuss his conclusions with a specialist member of the staff. ut advanced students vary in type, and their needs are best considered ‘Separately. _ The Research Student.—This student is frequently a man of established scientific reputation. He requires only original material, and this must be furnished with full data of provenance, evidence of its type distinction or other points of interest, and full references to literature. Probably all other specimens of similar type possessed by the Museum will be required for comparative study, and all these should be supplemented by information similar to that of the study ‘Specimen or specimens. When the material cannot be brought together in a room suitable for study, provision for the accessibility of the series is necessary, the Index catalogue will be required, and cases and cabinets must be open. When required specimens are on exhibition, as they needs must be in m>«y, cases, it will be necessary ‘to dismount them, or if this is impossible, work must proceed at the open case, @ most undesirable method. For the satisfactory work of a researcher, a well- lighted work-room is essential. ., , Access to a good library is also essential, and very little good work is done if books are only available for short periods on Joan. 1920 ui) 974 REPORTS ON THE STATE OF SCIENCE.—1920. Instruments ot research will be required, such as microscope, preparatory and developing tools, photographic appliances, &c. Everything which the researcher requires for the thorough prosecution of his studies ought to be at hand. The needs of the researcher at a distance entail less calls upon the staff, and are usually restricted to the loan of specimens, plaster casts, and tull details of provenance, &c. Uhe University Student.——Under this head we include the students of all advanced training institutions, whether University or not. Where calls are many, and on similar lines, it may be possible to form special ‘ Students’ Series,’ from which the student can gain a practical knowledge of his subject. Hither lack or excess of material beyond what is absolutely required is a disadvantage. The material will be chosen for its instructive value, not for its attractiveness. A special Student Series can be kept on exhibition, from which it is not removable, or in cabinets, so that its use throws no additional work upon the curator, Special Student Series should be available for use by the lecturers to advanced students, as well as by the students themselves. If required in the lecture-room, the collection should be kept in drawers, and not exhibited, unless special rooms, not open to the general public, are provided. Exhibited series, which have been specially selected, arranged, and labelled in the public exhibition cases, at times fall under the head of Special Students’ Series. ‘These collections should have references to the literature dealing with the subject. The arrangements should allow students to use note-books, or a small table. Most, if not all, of the specimens in the series will have to be handled by the student, and numbers corresponding to a catalogue list should be painted or otherwise’ fixed upon each. University students frequently work in pairs, or small numbers, and need to have several specimens before them at atime. Suitable rooms must, therefore, be provided for their special use. There remains the larger question of co-operation between the University and the Museum. The public Museums in most of the University towns are large and well provided with collections, in which there is a considerable store of material suitable for research. The staffs usually include one or more trained scientific men, and more such are being attracted to permanent Museum work. We believe that, with good will and intelligent co-operation between the University and the Museum, difficulties will disappear, to the great gain of both institutions. For University professors to restrict themselves to a Museum of their own is to restrict themselves and their students to a limited field of observation and research, as the public Museum is always likely to contain and receive more material in any subject than the University is normally likely to acquire. The curator, on the other hand, must conserve, suitably labelled, and keep in good order, extensive collections which are of primary value both for teaching and research. Mutual aid cannot fail to bring in good results. The professorial staff of the University can help by furnishing scientific or artistic knowledge, and by supplying dissections, prepared in the laboratories. They can assist the curator in the preparation of exhibition groups of current — scientific importance, and can in turn profit by a first-hand acquaintance with — material in sections of their own science, which may not fall within the range of their ordinary professorial teaching. F Such a co-operation is merely extending to independent Museums what is already done in those directly connected with a University, as at Oxford, : Cambridge, Liverpool, and Manchester. It is, however, in the United States that the best examples of co-operation are seen. (See Appendix I.) The advantages of this intercourse are many. Expense is shared instead — of duplicated, and through the intermediary of the Museum the public is brought into close contact with the higher seats of learning. The Museum comes into its rightful place in the fighting-line of science, and the student comes face to face with actual problems and gets a close grip of connected facts; he in fact does work under more real conditions than in the forcing house, or laboratory. But the student, too, may fairly be asked to help by doing some curatorial work. Instead of disarranging and damaging Museum specimens, let the post-graduate prepare, determine, label, and arrange a limited ae eee eS ON MUSEUMS IN RELATION TO EDUCATION. 275 group under the joint direction of professor and curator. The Museum will profit by the improved arrangement of the objects, and the student will learn how to utilise specimens, and how to discover and use the relevant scientific, or other, literature. Such work will also give him a solid foundation of syste- matic knowledge too often wanting even in the best products of modern education. The Private Student.—This student is usually either working for an examina- tion or to perfect himself in a subject which appeals to him. If of the former type, he may find all he wants in the exhibition series, with a little guidance from the curator, or it may be necessary to give him access to the series used by the University student. The needs of the second type of student will generally be amply supplied by the explanatory labels, and occasional access to books. The Collector Student.—This student usually visits the Museum in order to identify specimens in his own collection, and therefore requires access to systematically arranged and stored collections. As the exhibited series will not, or ought not to,. contain the long series of specimens he desires to see, these students will be best served and helped if Museums used by them provide one or more well-lighted work-rooms, with large tables, adjacent to the reserve series, which should be kept in strict systematic order, and fully labelled. The rooms containing the reserve stores can frequently be used as work-rooms for the advanced students also, and with great advantage, as specimens. can be returned to place at once when done with, before others are taken out. Museums in Relation to Classical Education and the Humanities. Much of what might be written upon this branch of Museum work has already been published in book form by a member of the Committee, and need not be repeated again here (‘Our Renaissance: Essays on the Reform and Revival of Classical Studies,’ by Professor Henry Browne, 8.J. Longmans, Green and Co., no date of publication). Professor Browne rightly urges that, whilst the subjects of Natural Science may claim priority, Museums which neglect the promotion of the love of culture and art among all classes will be incomplete and one-sided. Teachers of Ancient History may reasonably expect to find, in Museums, collections having a bearing upon the subjects they teach, and in some of the large provincial Museums this is already the case. No Museum, however, need consider itself too poor or remote to be able to do something towards illustrating ancient life. The objects required for the purpose can be so chosen as to appeal to the public as well as to the student, and success will depend upon the exhibition of such material as ought to interest persons of average intelligence and educa- tion. The bringing together of local or other evidence of the Roman occupation of England, for example, will attract. every one. Much can be done by the provision of reproductions (including casts and electrotypes, as well as photo- graphs and slides) of objects not otherwise obtainable. Many of these being replaceable, could be loaned to schools and colleges. From a special questionnaire much information was obtained, and can be found set out in full in Professor Browne’s book. It will suffice if a summary only is given here. Practical evidence of the value to all grades of education by such collections in Museums was supplied by the authorities of the British Museum, and of the Museums of Oxford, Cambridge, Liverpool, and the Universities. In this instance, again, American Schools of Learning and Museums are far in advance of the British Isles. The greatest development has been reached by the Museum of the University of Pennsylvania, Philadelphia, which is a University and Public Museum combined. The classical and art collections are remarkably good, and fully used by the University professors, who find that the interests of students are stimulated and encouraged, whilst their studies take on a more real character than from bookwork alone. The Boston Museum of Fine Arts is doing much useful work, and teaching is carried on upon a large scale. The collections are used by the students of Harvard, and T 2 276 REPORTS ON THE STATE OF SCIENCE.—1920. by Public Schools. In one year lectures were delivered to nearly 12,000 people by ‘ Docents’ of Academic aistinction. The Museums of most of the American Uniyersities possess a strong ciassical section, and all are used for instruction purposes by the professors. i ; y "he Archxological Institute of America is steadily encouraging the extension of classical teaching, and specially promotes a knowledge of ancient cultures. It also gives support to, and derives material from, the Archzological Schools of Athens, Rome, Jerusalem, and Santa Fé (New Mexico), and publishes journals which have a large circulation, Forty-five local branches, arranged in four geographical sections, are in operation, and from 200 to 250 lectures are arranged tor yearly. The study of classical history will probably increase in the near future by reason of the renaissance which Eastern countries will experience as the result of the recent war, and collections which illustrate, even fragmentarily, some features of their ancient history, will be of great service, but any extensive development of such collections will necessarily be restricted to the large cities and University towns. Principles of Museum Administration, Maintenance, and Staffing. The determination of any general principles of government and administra- tion does not appear to have been formulated or applied to British Museums. Neither are British Museums, or their governing bodies, referable to a common standard, even when they exist mainly for the benefit of the general public. The Libraries Act, 1919, may eventually secure uniformity of government for county and town Museums, although it is optional for a county or town to place its Museum under the control of the Library Committee, or under a distinct Museum Committee. The many public, or semi-public, Museums, owned by societies and private bodies, are not recognised by the Act, and no inducement or provision is made for their transference to the constituted public authority. These will, therefore, remain under their present diverse methods of administration, and be governed more in the interests of the societies, than in that of the general public. This is to be deplored, as many of these Museums contain the nucleus. of a good public Museum, and many national] treasures, yet cannot develop sufiici- ently for want of funds, whilst they are large and important enough locally to hinder the formation of a wholly free public Museum. No fixed rate per % can be devised applicable to ali Museums, as the differential rateable values, population, and requirements of towns cannot be brought to a common stan- dard, It is possible, however, to fix a minimum income based upon the cost of maintaining a trained curator at an adequate salary, one attendant, and cleaners. (No curator of average ability ought to receive less than 300/. per annum, and this amount, added to the wages of attendant and cleaners, will, with the fixed charges, and at least 150/. for purchases, printing, &c., entail a minimum cost of 800/. per annum.) It is essential that each department of a Museum should have a definite sum allocated for purchases, mounting, labelling, &c., otherwise the balance of sections is likely to be destroyed by the enthusiasts of one or more sections. This is a prime fault in provincial Museums. The principles and cost of maintenance of a Museum are questions not always capable of settlement by the local governing body, and these would profit considerably if it were possible to seek the advice of some recognised national or central authority fully conversant with the cost, maintenance, and development of the various departments suitable for a Museum in a given ‘town or district. The help of such a body of experts would also assist local Museum Committees in securing a suitable balance of departments and an economic expenditure. In order that the Museums may fulfil their proper mission in the community it is obvious that the question of staff is of the first importance. The old practice of uniting the functions of librarian and Museum curator is vigorously and unanimously condemned by, the Committee. Progress of Museum work depends upon the formation of an adequately paid corps of specialist workers. At present all Museums are understaffed. Even in small Museums, a single tnrator cannot be sufficiently well informed to arrange and label all his material, ON MUSEUMS IN RELATION TO EDUCATION. 277 Large Museums will require two or more members of staff, each of whom should have extended his general preparatory training by special study of those groups with which he is called upon to deal. The National Museums have for long specialised the work of their members of staff. They require of them a high standard of attainment. A few of the provincial Museums have secured directors and curators with recognised qualifi- cations in science or in art, but the greater number of curators are either self- trained or have acquired their special knowledge on other than systematic lines of study. Notwithstanding the lack of preliminary systematic training, most curators have acquired qualifications which fit them adequately to perform their present duties. It is evident, however, that future Museum work will be best served if Museum assistants and curators have previously passed through a systematic course of instruction in those sciences and arts likely to be needed in their subsequent work. A sound University training in letters or in science must soon be a sine gud non. It is also desirable that the elements of Museum technique should be taught whenever means can be devised. A reading know- ledge of French and German is almost indispensable. It is generally admitted that Museum officials are badly paid—that is, their stipends are less than similar attainments and powers of mind would earn in other walks of life. Considerable improvement has taken place in this matter during recent years, but adequate progress in this direction ‘can only: be effectively made when the curatorship of a Museum is looked upon as an honour- able and desirable profession for men of high intellectual attainments’ (Sir W. H. Flower). Some General Conclusions. Many of the recommendations of the Committee-are embodied in the Report, but there are one or two general questions which may be briefly referred to here. 1. In the view of the Committee, Museums can and should be developed into centres of research. This may be done partly in co-operation with Universities. Much unworked material lies in many Museums, and a wide field of useful research lies open, if suitable facilities for the work are provided. 2. It would assist research if an official list of the principal contents of all provincial Museums could be published by the Board of Education. This list would also doubtless indirectly increase local pride in the collections and so add to the steps taken to secure safe custody. 3. All Museums suffer greatly from want of funds. If educational work and research are to be developed. grants-in-aid on a liberal scale are absolutely essential. There is some fear that Museum funds may be seriously diverted from what all authorities agree to be their first aim—viz.. the advance of knowledge. for the more popular ventures in connection with the schools. Research must be regarded as the first function, at any rate, of all the greater Museums. Some principle of grading of Museums for purposes of grant might be adopted, based upon the work they are doing or planning. 4. Curatorial functions demand a high degree of special knowledge and training. The Universities and the National Museums have a duty to the nation in this respect. 5. In reference to the work Museums may do for schools, the Committee helieves that the system of enecial circulating loan collections for schools. so highly elaborated in the United States. deserves wider extension in this countrv : and it recommends that, to pav far the necessary material and the svecial staff required, annropriations should be made from the Education grant to _those Museums which are prepared to carry out the system. APPENDIX T. Sub-Committee’s Report upon Overseas Museums. (a). Australia.—The Committee’s delegates visited the Australian Museums at. Perth, Adelaide, Melbourne. Sydnev. and Brisbane. and found that the general work of each was carried out on similar lines to that in British Mvseums. The fundamental purpose of Museums is well maintained, all material bearing upon 278 REPORTS ON THE STATE OF SCIENCE.—1920. the aborigines, native plants and animals, and the mineral resources of Australia is carefully conserved. The Art Gallery attached to the Melbourne Museum takes special cognisance of examples of Australian Art. Public lectures are given at all the Museums, and schools and classes encouraged to visit them, the Museum staffs giving demonstrations and lectures whenever possible. Special student collections are being made at Perth, Adelaide, and Brisbane. The Technological Museum, Sydney, loans collections to illustrate lectures given at the Technical Colleges and Nature Study in schools. Timber, minerals, building and ornamental stones, &c., are in process of collection in order to constitute an exposition of the mineral wealth of the country. It also sends out collections of native material to distant towns and schools. The educational work of the Queensland Museum, Brisbane, is on a more extensive scale than elsewhere. Carefully graded lectures are given by the Museum staff to classes from elementary and secondary schools, and special time is allotted to classes for definite studies. Higher education and research receive special attention, research being specially encouraged. (6) Lhe United States.—Adequately to describe the educational activities of the American Museums would require a large volume. The Committee’s delegates visited those at Chicago, Pittsburgh, Washington, Philadelphia, Harvard, Boston, Brooklyn, and New York. Time did not allow of more extended visits, but information was readily obtained from all to which applica- tion was made. The Museum of Natural History and the Metropolitan Museum of Art, New York, the Museum of the Academy of Sciences, and the Field Museum, Chicago, the Carnegie Museum, Pittsburgh, and the Museum in Philadelphia were pre-eminent amongst those visited for their extensive schemes of educational work in connection with the Public Schools. They are also actively associated with higher education and University work, as are the Museums of Washington, Harvard, and Boston. The work of the Natural History Museum, New York, may be outlined as an example of what most American Museums are doing -to aid education, as it has probably done more work of this character than any other Museum in the world. Large circulation sets of Nature Study collections have been prepared, and in 1913 were sent out to 501 schools by means of special motor vans. These collections were used by one and a quarter million of pupils. The study collections number about 600, and have been much increased since. Special teaching collections are set up in the Museum, and class-rooms and lecture theatre are available for use at any time. Members of the staff frequently lecture to the children and to the teachers, whilst a special guide service is maintained. Special provision has been made for blind students, who are permitted to handle specimens. It is said that they gain in this way quite a remarkable knowledge of the form and adaptations of animals. A Lantern-slide Department has been organised for some years, and now possesses over 30,000 slides, which are loaned in series to schools for teaching purposes. At the time of the delegates’ visit the formation of. branch teaching Museums was under consideration, and the establishment of ten Lecture Centres in various parts of New York. The needs of higher education and research have been met by an arrangement with the Columbia University; the professors lecture to their students at the Museum, and hold the position of curators in the Museum in their several subiects. .The Metropolitan Museum of Art, New York, retains expert guides to assist its members, teachers, and schools when visiting the collections. The service is free to teachers and schools. The city maintains one paid lecturer. Regular visits are paid from schools for instruction in the History of Art. The University and Museum are in close co-operation, especially on the classical and historical sides. It has been suggested that a Faculty of Arts should be established in the Museum, with lectures for snecial collections. The Boston Museum of Fine Arts and the Art Institute of Chicago are doing similar work; in the latter case. a School of Art is maintained in connection with the Museum. _ The Field Museum of Chicago has entered upon an ambitious scheme whereby a specially prepared series of Circulation Collections will be available for schools..in the city area, A quarter of a million of dollars was given for this ON MUSEUMS IN RELATION TO EDUCATION. 279 purpose, and has since been increased. The work of the Academy of Sciences, Chicago, and of the Children’s Museum at Brooklyn, is remarkable in that the children are encouraged to take part in the Museum work, by the maintenance of aquaria, the loan of specimens to be taken home, and the preparation of costumes, &c., to illustrate the clothing of various periods and nations. Classes in the natural and physical sciences are taught in the Brooklyn Children’s Museum by the staff, and many children have become expert in wireless tele- graphy, blow-pipe analysis, and in the use of other scientific instruments, The Public Museum, Milwaukee, possesses a full lecture system reaching all sections of the public from the elementary schools upwards, and has established a Science Club for High School Students. Arrangements are made for all Public-school children of certain grades to visit the Museum twice yearly. The American Museums make free use of Museum and Art ‘Docents’ for the delivery of lectures and demonstrations. These ladies and gentlemen are chosen for their special knowledge, and are maintained either by the Museum or the city, or partly by both, or in some cases, as at the Brooklyn Institute of Arts and Sciences, by an Art League. The two ‘Docents’ of this Museum lectured to 114,000 pupils in one year. The American Museums are in a position to undertake this valuable educa- tional work owing to— 1. Large gifts of money from wealthy persons. 2. Large staffs of enthusiastic workers. 8. The association with every Museum of a large body of rich and cultured people, who are themselves interested in the collection and study of Museum objects; they frequently give large sums of money for general maintenance, or earmarked for special purposes, and also present private collections. As educational work extends, the popularity and usefulness of the Museums increase, and their purpose and utility become more highly valued. The attain- ments of the staff are recognised, and opportunity given for the prosecution of their own line of research. An essentially American feature in the formation of new Museums is the preparation and publication, long in advance, of full plans of intended new buildings, and their free display in journals and public places. Reduced models to scale are also prepared of the suggested buildings, and these are exhibited to the public. These people do not hesitate to embark upon schemes’ which will take years of work to accomplish. Definite steps forward are taken as opportunity arises. but the whole scheme is kept prominently before the public as an earnest of the future and a stimulant to gift. APPENDIX II. Manchester Scheme. Ar the beginning of the war several of the elementary schools in Manchester were taken over for military hospitals, and the scholars, therefore, temporarily dispossessed of accommodation. The Education Authorities thereupon instituted a half-time system in certain of the remaining schools, in order that the dis- possessed scholars should receive, at least, some instruction. It was decided in these half-time schools to fill up part of the remaining half of the scholars’ time by visits of educational value to various Manchester institutions and other places of local interest. In this connection the Keeper of the Museum, in con- sultation with the Education Authorities, organised a scheme whereby the scholars attended at the Manchester Museum for courses of lessons in Natural History and Egyptology. The main points of the scheme are as follows :— 1. The classes are limited to twenty in number. 2. The classes are, as far as is possible with existing accommodation at the Museum, provided with separate class-rooms, seating accommodation, desks, &c., so that the lessons are given as nearly as possible under school conditions. 3. The teachers are trained teachers on the staff of the Manchester Education Committee. who have also a special knowledge of the subjects illustrated in the Museum. They have heen specially appointed to this work by the Education _ Committee. 280 REPORTS ON THE STATE OF SCIENCE.—1920. 4. The classes do not come for detached lessons, but regularly once a week for organised courses of six to nine lessons on one subject. 5. The Museum authorities provide duplicate specimens for the use of the classes, and the staff of the Museum render as much assistance and help in this way as possible. 6. A lesson, broadly, consists of about forty minutes’ tuition in the class- room, after which the class is taken into the Museum and shown the cases illustrating the subject of the lesson. At first eight classes in Zoology and Geology were held daily, and from 900 to 1000 children per week shared in the lessons. The scheme proved remark- ably: successful, and two additional teachers for Botany were added the following year. Class-room accommodation was a difficulty, and a part of the Museum had to be shut off for'the purpose. It became clear, however, that work of this character requires a Museum lecture-room and class-rooms to obtain the best results. The increased demands upon the time of the Museum staff in providing material were considerable. By 1916-17 the scheme had so far proved its value that four teachers were specially appointed by the Education Committee to conduct Museum classes throughout the year in Geology, Zoology, and Botany. Towards the end of the session a fifth teacher was appointed, whilst the assistant in charge of the Egyptological collections also conducted classes. The attendance of scholars increased to 2000 per week. In 1919-20 the number of special teachers was increased to six, and the number of scholars attending the courses to 2500 per week. Classes from the secondary «chools also visited the Museum, and were taught by their own teachers. The development of this valuable educational work reacted upon the Museum in increased public interest, whilst a considerable addition of adult visitors was brought by the scholars in their spare time. The total attendance for the period of four years was as follows :— 1915-16 . . . 45,000 | 1917-18 <9." . 100,000 1916-17 ©. . . 70,000 «| «1918-19 ©. ~—. |. 1805000 It must be borne in mind that these were not discontinuous attendances, but represent the total visits at complete courses of six to nine lessons for each scholar. Some scholars attended more than one course per year. The Manchester scheme was adopted after a close study of the educational work conducted in other Museums in this country, and especially in America. Compared with other schemes and methods, it is claimed that the Manchester scheme shows considerable advantages in the following ways :— 1. The limitation of the classes to small numbers. It was felt that to attempt to instruct large classes resulted in ‘ entertainment’ and not ‘ instruction.’ ps atmosphere of the school class-room is approached as nearly as possible. ‘ This is valuable from a disciplinary point of view, and also avoids physical fatigue so usually attendant on visits from school children to Museums and such places. 3. The classes are taught by trained teachers and not by the Museum staff. The advantages of this from an educational point of view are obvious. The staff of a Museum is appointed primarily, for quite other work than teaching. and Museum curators do not pretend to understand the psychology of the child mind or to be trained in the art of teaching. 4. A proper balance is maintained between this branch of Museum work and the many other functions and duties which a Museum is called upon to fulfil, and the educational work can be carried on without the absorption of an undue amount of time, to the detriment of the other work of the institution. ee ee a ON TRAINING IN CITIZENSHIP. 281 Training in Citizenship.—Interim Report of the Committee, Right Rey. Bishop Weuupon, D.D. (Chairman), Lady Saw (Secretary), Lieut.-Gen. Sir Ropert Bapren-Powetu, Mr. C. H. Buaxtston, Mr. G. D. Dungertey, Mr. W. D. Eaaar, Principal Maxwei Garnett, C.B.E., Sir RicHarp Grecory, Mr. Spurnry Hey, Miss E. P. Hueues, LL.D., Sir THroporre Mortson. Introduction. TRAINING in Citizenship consists of two parts, subjective and objective. The former may be described as character-training and is concerned with the develop- ment in the individual of those qualities which fit him to take his place in a community with full appreciation of such privileges and duties as are the birth- right of every good citizen. The second part is concerned with the education of the individual in the history of civilisation and the laws appertaining to communal life which assure to every member freedom for full personal development cf mind and body. With this two-fold purpose in view it was decided to take, as far as possible in the limited time and with the limited facilities at the disposal of a small Committee of busy persons, a survey of the educational organisation of this and of other countries from which information could be acquired for practical train- ing of the young in citizenship, and, further, to draw up a syllabus of theoretical instruction which would be capable of expansion into an authorised text-book on civics. A letter contributed by the Chairman appeared in The Times Supplement for December 25, 1919, asking for help in compiling the items of the survey. From the answers to this appeal it was evident that the pressing need was for the syllabus. It did not, however, appear that one syllabus could be prepared to meet all cases. A request came from Bootham School, York, for ‘ short courses on the training of citizenship as well as long courses,’ ‘ to help in a practical way schools that uphold the idea of citizenship throughout the school career, and are unable to find the time for more than a short intensive course of lessons.’ Similar requests came from other schools, but the greater number of correspondents asked for an authoritative handbook of civics, and it was decided to take up this work and to meet the other varying needs by appending a selection from the specimen syllabuses and suggestions for lessons that were sent to the Committee by schools and associations interested in the work. The Preparation of the Syllabus. The Chairman, at the request of the Committee, drew up and circulated a detailed syllabus of civics which after criticism by the Committee was expanded by Mr. Dunkerley from reports sent in by school teachers and from suggestions made by members of the Committee and others and from his own. experience. The syllabus thus expanded was again considered by the Committee and adopted by them. It is included as Appendix I. in this Report. The Committee learned that Mr. Blakiston had in hand a Text- book of Civics designed for use in the senior classes of the Public Boarding Schools. This book has been completed on the lines of the syllabus, and the Chairman has contri- buted 1a foreword to it. ‘So important is it, however, that children of both sexes in all schools, and not least in elementary schools, should be systematically taught to recognise their duty to the Nation and the Empire that the Committee feel the time is opportune for issuing an official handbook upon Civic Duty; and, if the syllabus now printed should receive the approval of the Educational Section, they desire that a handbook on the lines of the syllabus should, if possible, be issued with the authority of the British Aggociation. They would invite 982 REPORTS ON THE STATE OF SCIENCE.—1920. Mr. Dunkerley, with the assistance of the Chairman, Bishop Welldon, and the Secretary, Lady Shaw, to undertake the task of drawing up such a book. The Committee entertain the strong opinion that the handbook, while supplying information upon various aspects of municipal and political life, should aim especially at inculcating the unselfish patriotic spirit which would. as they believe, go far towards preventing, or at least mitigating, the industrial contro- versies now threatening to undermine the basis of society. The Selected Syllabuses. In response to their inquiry into the work now carried on in various educa- tional institutions, the Committee received a number of syllabuses and notes of lessons which may be of use and which will certainly interest the members of Section L. soi : The difficulty has been to decide which to reproduce when so many were of equal value. Those appended have been selected because they include special points not common to all. Examples of Courses in Citizenship. Sir Robert Baden-Powell’s scheme needs no comment by the Committee. Its practical value has been thoroughly tested and proved. It is reproduced as Appendix II. Appendix IIT. contains the following :— A. The Devon County Education Committee’s Report, 1911. Suggestions as to moral instruction and training in citizenship. B. The Hammersmith syllabus supplies an example of the short. intensive courses for which many schools made inquiry. C. That from Blackley. Manchester, is admirable as showing how the schoolboy may be trained to be a good citizen and patriot in the widest sense of the word. D. Caerau Mixed School. Bridgend. gives its syllabus of lessons, and the school self-government scheme by girls and boys working together. E. The Roath Park Boys’ School. Cardiff. sets out (1) a Citizenship scheme taken as part of history, (2) the Prefect system, which includes self- government, and (3) an experiment in Scoutcraft as a school subiect. F. The syllabus from First Derry (Ireland) Boys’ School is a specimen of courses in Civics followed in certain Irish National Schools. G. That from Stobswel] School is a specimen from Scotland. Schemes of School Management. Appendix IV. contains the following :— Skerton Council School. Lancashire; the statement is long, but has great value as that of a school having a ‘ constitution.’ Cowley pace, St. Helens, Lancashire. This account is written by a boy at school. Penarth County School, Wales. This is written by a girl at school. Roath Park Boys’ School : Section on the Prefect system. Roath Park Boys’ School : Section on Scoutcraft. High School, Glasgow, describes a system of Prefects. Appendix V. gives Lord Lytton’s Suggestions for Organising Regional Study and Maintaining a Permanent Regional Record. Appendix VI.—Mr. Valentine Bell : Notes of Lessons in Regional Survey. A circular letter was sent on December 12, 1919, to the Secretaries of the Head-masters’ Conference and to the Associations of Head Masters. Head Mis- tresses, Assistant Masters, Assistant Mistresses, Private-school Masters, Private Schools, Science Masters. and Training Colleges, asking them to bring the matter to the notice of their members. It was also sent to Newnham and Girton Colleges. Of these the Committee of the Head-masters’ Conference agreed ‘to print the statement contained in the Jetter in their termina} Bulletin’ in February ON TRAINING IN CITIZENSHIP. 283 bf this year. The Private Schools Association inserted a notice, supplied on the invitation of the President, in their paper ‘ Secondary Education’ on February 1. Newnham College, Cambridge, inserted the letter in their journal, the ‘Newnham College Roll.’ The Association of Science Masters put the Committee in touch with the Catholic Social League. All the Secretaries promised to bring the subject to the notice of. their Committees. Tue Epucationat SuRVEY. The Committee decided not to confine their survey to the United Kingdom, but to include as far as possible notes of educational methods throughout the British Empire; and, for the sake of comparison, to ascertain the latest developments in other countries. For this last purpose they have asked the help of the Education Section of the International Council of Women, which is engaged in a similar investigation. The response to the inquiry instituted by the International Council is not due in this country before the meeting of the British Association in August; and replies to the Committee’s letters addressed to Japan and China have not yet been received. It is therefore not possible to present a report of the survey to the meeting in August 1920, and this must be postponed to 1921. The Section should, however, be in possession of some account, of the action taken by the Committee to ensure complete informa- tion for the final report. In Canada in 1917 a movement was started at Winnipeg ‘ for a National Conference to consider the bearing of Canadian Education on Character and ‘Citizenship.’ After a considerable amount of preparatory work, money was raised and the Conference was fixed for October 1919. This Conference was attended by about 1,500 accredited delegates of public offices, the aim being to gather business men and educators in one great assemhly to secure the creation of a permanent body for study of the question. The Committee have received a verbatim report of this Conference, the attendance at each session of which was never less than 2,000 persons, and on one evening rose to 5,000. The report says ‘the distinctive features of the gathering were its diversified representative character, the combination of citizens as such and professional educators. and the spirit of lofty ideality in the interests of the nation that animated all.’ The outcome was the creation of a National Council of fifty members, thirty-six to be elected from the various provinces by the Conference itself, and fourteen to be elected by the Council as so far constituted. This Council met in February of this year, and the report of their proceedings has been supplied to this Committee. Inquiry has now been made of four nrominent men whose names were supplied by Professor Macallum, of Toronto University, asking what effect, if any, has been pro- duced in the schools or in any way, and also asking for information as to the training given in the schools. The Committee hope some similar action may be taken in the Mother Country. A list of voluntary agencies for dealing with Civic Education in the United Kingdom is being compiled. Meanwhile the Committee have obtained varticulars of methods of work from the National Federation of Teachers. the Schools Personal Service Association, the Citizenship Studies Association, the Union of Educational Institutions. the Union of Lancashire and Cheshire Institutes. the Workers’ Educational Union, the Catholic Social League, the Civic and Moral Education League. the Federation of Women’s Institutes. and the Cavendish Association. A circular letter has been sent to thirty-six head-masters and sixteen head-mistresses of public schools, to two mixed schools and to two private schools. The answers received will be considered in next year’s report. Application was made some years ago by a Committee of Section L to the Roard of Education for lists of private and of charitable schools, and County Directors have now been asked for lists of such schools in their respective areas, but neither the Board of Education nor the local education authorities keep such records. Further efforts will be made to obtain the necessary data to complete this part of the survey. From the Roard of Edveation the Committee have received conies of ‘Suc- gestions for the consideration of Teachers and others concerned in the work of 284 REPORTS ON THE STATE OF SCIENCE.—1920. Public Elementary Schools’ and of the ‘ Syllabus of the Board’s Final Examina- tion of Students in Training Colleges, 1922.’ There are sixty-eight County Directors of Education in England and Wales. A questionnaire was prepared for these, and Miss E. P. Hughes undertook its circulation to the twenty-nine County Directors in Wales. In addition to the thirty-nine questionnaires distributed in England, personal letters were written to eight other Directors of Education. The response was not complete, but a mass of valuable information is in the hands of the Committee to be dealt with later. Much time has not elapsed since the appeal was sent to Scotland and Ireland, but some returns have already been received. A considerable amount of work remains to be done before the survey can be considered to be complete. Since this report was drafted the Committee have received from Mr. Shyam Shankar, Pandit and Secretary to H.H. the Maharajah of Jhalawar, the terms of a proposal for a Students’ League or League of Empire for Native Students in India, which has practically the same objects as the schemes which ‘are heréin referred to. The draft will be considered in connection with similar proposals for other parts of the Empire in a future report. The Committee desire to record their thanks to all who have given assistance so far, and, since ‘ gratitude is the sense of favours to come,’ they look forward to additional help in pursuing the research and preparing a final report. ON TRAINING IN CITIZENSHIP. 985 TABLE OF APPENDICES. I. Syllabus of Instruction in Civics prepared by the Committee. 1I. Analysis of the Scout Scheme of Training towards Citizenship, by Lieut.- Gen. Sir R. Baden-Powell. III. Examples of Courses in Citizenship selected from other sources :— . The Devon County Education Committee. . The Ellerslie Road School, Hammersmith. . Blackley School, near Manchester. . Caerau Mixed School, Bridgend, Glamorgan. . The Roath Park Boys’ School, Cardiff. . Ireland : First Derry Boys’ School. Scotland : Stobswell School. QAO pS IV. Schemes of School Management :— Skerton Council School, Lancaster. Cowley School, St. Helens: Boy’s Essay, ‘ Civic Government by Boys,’ Penarth County School for Girls, Wales: Girl’s Essay, ‘ Self-Govern- ment.’ Roath Park, Boys’ School, Cardiff. The High School of Glasgow. V. Suggestions for Organising Regional Study, by the Earl of Lytton. VI. Notes of Lessons in Regional Survey (Lambeth), by Mr. Valentine Bell. APPENDIX I.—SYLLABUS PREPARED BY THE COMMITTEE. 1. The Origin of the State. Man a social animal. Impossibility of his living a solitary life. The family the birthplace of the State. Plato and Aristotle upon the origin of the State. Augustine upon the Christian State. Society implies interdependence; interdependence implies division of labour or specialisation. Social unity of groups—Family—Guilds—Trade Unions, 286 REPORTS ON THE STATE OF SCIENCE.—1920. Two objects of the State :— (1) To produce worthy and contented citizens. Common interests of all who are members of one Society, e.g. in obtaining the necessities of life, in securing the safety of person and property, easy communication, and opportunities of leisure and recreation. (2) ‘Lo promote progress. The State can do for individual citizens something which they cannot do for themselves. It can afford them means of know- ledge and culture. It can encourage education, temperance, and civic and patriotic devotion. It can offer opportunities for development and ele- vation. True freedom lies not in self-assertion but in subordination to the public good. Civilised man more truly free than a savage. The State, therefore, essential to human welfare. But as every organism in its development becomes more complex, so a modern State with interests, it may be, in all parts of the world is far more complex than the ancient State, even when the ancient State had become an Empire. 2. The History of Civilisation. Process of civilisation from East to West. Influence of Greece and Rome. Life and death of States. Characteristics or tests of civilisation. Man’s command of Nature. Influence of discoveries and invention, such as printing press, steam engine, aeroplane, gunpowder. Advance of civilisation, development of, Science and its applications and inventions. The great epochs of human progress marked by discoveries or inventions. Comfort. Standard of living. Comparison of modes of living during the Roman Conquest, English Conquest, Medieval Period (the Barons, Monks, &c.), Elizabethan and Victorian Periods. Interdependence of nations and countries—supply of wheat, wool, flax to England—coal, iron and manufactured goods from England. Growth of corporate life—association in (a) The Feudal Structure. (6) Craft Guilds. (c) Trade Unions. (d) Co-operative Societies. (e) Friendly Societies. Knowledge. Education: its opportunity and responsibility. Growth of Humanity, as in abolition of slavery, torture, &c. Treatment of women and children. The greatest happiness of the greatest number. International relations : interdependence. True end of civilisation :—The welfare of humanity as a whole. 3. Citizenship. Citizenship begins at home. Home life and surroundings. Type case in poor district, 60 houses on each side in a typical slum. Type family, father, mother, seven children (eldest 15). Type house, two bedrooms, small kitchen, parlour, only water supply.a tap in a yard. Importance of the individual; poverty no bar to success. Importance of knowledge of individual capacity; loss of much splendid talent owing to wrong occupations being taken up. Importance of individual joining some organisation with a definite object. Good health a necessity for good citizenship. Relation of the citizen to the State. Whether the individual citizen exists for the State, or the State for the individual citizen. ON TRAINING IN CITIZENSHIP. 987 Civic pride—a citizen of a great community with a glorious heritage in men and books. Interest in local history, natural history, and local industry, regional surveys. Historical records; public memorials, historical pageants. Civic ideals and duties. Unselfishness (good turns) and self-sacrifice. Individual service. Home. School. Care of buildings, &c. Outside. Public property (Parks). Proper use of conveyances and streets. Use of proper language. Community service. Country—Fire brigade, special constables, accident corps. Humanity—Hospital service. Religion—Mission work. Development of self-control. Consider gambling—smoking. Common Prejudices to be guarded against— At School—ridicule of dull and physically weak boys. Religion—bigotry ; sectarian jealousy. National—depreciation of members of other nations and races. Man is essentially and before all else a member of the State and must live up to that membership. Differences between the ancient and the modern world. Compulsory military service; if a citizen can claim security he must be prepared to fight for 1t if necessary, and the State has a right to call upon him to do so. Tendency of democracy to get as much as possible out of the State; to look upon the State as a dispenser of charities. A citizen’s right—a fair wage; a citizen’s duty—a fair day’s work. Universal franchise of adult men and women based upon equal interest of both sexes and of all classes in good government. Danger of party spirit; each party only a section, and not justified in seeking its own with little or no reference to the good of the State. The spirit of true citizenship evoked and evinced by the War. So great the debt of the citizen to the State that he may be justly expected to make large sacrifices for the good of the State. The daily life of a citizen. Great citizens :—discoverers, inventors, philanthropists, writers, musicians, artists. Desire of all classes to have a more permanent share in the Government, hence importance of all having a good conception of civic responsibilities : Franchise implies a duty as well as a right. Citizenship inculcated by practice, dramatisation, self-government (school commonwealths, trials, debates). ; 4. Monarchy and Democracy. Necessity for government. Forms of government : absolute monarchy, limited monarchy, oligarchy, republic. History proceeds as from East to West, so from the power of the few to the power of the many. Monarchy the only possible government in primitive society. Few good Kings and Queens. The divine right of Kings an exploded doctrine. Sir Robert Filmer’s Patriarch. The King the chief servant of the State. Constitutional monarchy still useful as ensuring the unity of State and Empire. The King to be recognised and to recognise himself as being what he really is. oy the healthiest government, as resting upon the widest and strongest asis. Democracy the only possible government in the modern world. Autocratic monarchy discredited. Object of the Great War to make the world safe for democracy, 288 REPORTS ON THE STATE OF SCIENCE.—1920. Drawbacks thought to be inherent in democracy : (1) that it may resist progress—Sir H. Maine and Mr. Lecky. (2) that it may fail to govern. (3) that mob-rule may prevail. Cf. Greek historians. No form of government without possible defects, e.g. ‘ vote-catching’ policy. Failure in Ireland. The need of strengthening democracy by constitutional safeguards, as in U.S.A. Burke’s criticism of democracy. Democracy indeed above other forms of government requires high character in its citizens. Modern tendencies: anti-centralisation. Bolshevist theory of the State. 5. Central Government. The State being one whole, a certain uniformity is necessary in its administration. Such variety of laws and customs as might prevail in the Heptarchy im- possible in the United Kingdom, Thus in U.S.A. authority tends to pass from separate States to the Central Government, in such matters as: the railway service, divorce, and temperance. In general, as a State grows larger, the province of the Central Government becomes restricted. Home Rule. Control of such matters as properly belong to the Central Government: Army and Navy and Air Services, Customs and Excise, Post. Office, Telegraphsi and Telephones, Taxation, Education, Foreign Affairs, including peace and war, marriage and divorce, and the liquor trade. Definitions of the functions attaching in the British Constitution to the Sovereign, the Prime Minister, the Cabinet, and Parliament. Lords and Commons. Election of Parliament. Exchequer. Direct and _ indirect taxation. Passing of Bills into Acis. The franchise and the ballot. Devolution now inevitable within the Cabinet itself. Sir Robert Peel probably the last Prime Minister who, tried to keep his hand upon all departments of administration. Danger of allowing the Government to be upset by a chance vote in the House of Commons. Disadvantage attaching to the American system of associating offices which ought to be permanent with the fortunes of a political party. Amount of agreement necessary among members of the same Cabinet. Value of permanent officials in a democracy. 6. Local Government. Danger of a Central Government being overburdened by a multitude of tasks. The British Parliament a signal example of the difficulty arising from excessive centralisation, Examples of local questions with which Parliament is obliged to deal. Devolution possesses the advantage of an appeal to local knowledge, local interest, and local patriotism. Scotland and Ireland respectively instances of success and failure in combining local with general sentiment. Value of Municipal life. Unity of all large cities except London. The Central Government to enunciate principles; the municipalities to execute ; them in detail. Good work already done by local Boards of Guardians, local Education Authori- ties, &c. Difference between rates and taxes. Money collected locally to be as far as possible expended locally; revenue from dog licences, &c., expended in county in which licence is taken out. Lord Mayors and Mayors. ; County Councils. Councils of County Boroughs, other Boroughs, other Urban districts, Rural districts. Parish Councils, Boards of Guardians. ON TRAINING IN CITIZENSHIP. 989 Functions and duties of statutory and other Committees. (a) Municipal levies and expenditure—e.g. provision of Municipal baths parks, trams, libraries, &c. ; (6) Education. (c) Provision for Public Health, including the care of the insane, and Housing. (d) ae for the destitute poor. Poor Law, almshouses, workhouses, casual wards. (e) Maintenance of roads, streets, buildings, and land. (f) Police and justice. Licensing. Gas, electricity, and water supplies. The danger that the best citizens will stand aloof from local administration. All honour due to the men and women who often spend their lives without remuneration in the service of their cities and towns. Municipal life as a training ground for political life. Importance of dissociating municipal life as far as possible from political partisanship. Use of local history. Description of the way in which a city or borough is governed. Tendency to extend governmental power and interference. 7, The Administration of Justice. The supremacy of law one main feature in civilisation; justice said to be a reflection of the Divine Nature. The law of a country to be (1) clearly defined; (2) popularly known; (3) equally administered. Distinction between civil and criminal law. The presumption of innocence in an accused person. Jurors—how appointed ; their powers and duties. Classes of persons exempted from service on juries. Defects of trial by jury. Rights of individual citizens as guaranteed by laws; above all, the Habeas Corpus Act and the Bill of Rights. Equality of all citizens before the law. Rights of women as well as of men. Incorruptibility of judges not established without difficulty, but now an assured fact of public life in Great Britain. How laws are enacted and how law is gradually developed so as to become applicable to changing conditions. Sir H. Maine on law. Value of assizes. Law to be made cheap and easy, but not so as to facilitate vexatious litigation. Tendency to substitute judicial arbitration for trials by law. 8. The Police and Public Safety. Civilised society differs from barbarous society by the maintenance of law and order. All citizens entitled to perform their daily avocations in peace and safety. Dangerous state of the roads, even so late as the beginning of the nineteenth century. Highwaymen on the outskirts of London. Numerous robberies and robberies with violence. Popular sympathy often on the side of the highwaymen as being supposed to be friends of the poor and enemies of the rich. Inefficiency of the police down to 1829. The police force as then instituted by Sir Robert Peel. Difference between it and its predecessors (among these were the watchmen known as ‘ Charlies’). Occasions of appointing special constables. The Riot Act. Power belonging to local authorities in grave emergency. The Peterloo massacre: Training of the police. Their functions and powers. Women police. Relation between the police and other citizens. 1920 U 290 REPORTS ON THE STATE OF SCIENCE.—1920. Friendly attitude of all classes except the criminal class to the police. Juvenile offenders. Prevention better than cure. Schools rather than prisons. The Borstal system. Reformatories. Police-court Missions and Discharged Prisoners’ Aid Societies. Perils attaching to misuse of cinematograph shows. The young of both sexes to be instructed in the laws which they are called to obey, and to be taught that the law is the only safeguard of liberty, as civilised men, although subject to more control, enjoy far more liberty than uncontrolled savages. 9. Public Health. Health of the nation a chief concern of the country or city. The Prime Minister’s statement that a million more men would have been available for military service had the conditions of physical welfare been observed. Impossibility of making an A1 nation out of C 3 men. Every child to have the chance of a healthy physical and moral life. The State slowly waking up to its duty in respect of public health. Reports of Medical Officers of Health. Health Insurance Act. Royal Commissions. Provision of hospitals, clinics, and nurses. Legislation affecting mines and factories. Laws of Health. Habits making for good health— (1) Exercise—sports—swimming—outdoor life. (2) Cleanliness—body and mind. (3) Temperance in every way. (4) Insistence on good ventilation. Many diseases shown by experience to be wholly or nearly preventable, e.g. small-pox, diphtheria, and, above all, hydrophobia. Leprosy and Black Death long since extinct in Great Britain. Ravages of venereal disease. Report of Royal Commission. Immediate measures to be taken for check- ing and curing the disease. Sanitation itself—a recent study. Effort and achievement of Sir E. Chadwick, Importance of good sanitary conditions in schools. Neglect of conditions even in public schools. Statistics of infantile mortality. Need of instruction upon maternity. Peril of drunkenness to health and life. Clinics. Care of crippled and defective children. Treatment of defective eyesight. Crusade against dangerous employment. White lead. ‘ Phossy jaw.’ Warm clothing as a preventive of chills and consequent maladies. Injury that women may do to themselves by following fashions in dress, Provision of nurses for the poor in their homes during sickness. Cleanliness. Free public baths. Free medical attendance. Hospitals at present inadequate to number of patients. Quests ate hospitals voluntarily supported as against hospitals dependent on e rates. Welfare work. A healthy and skilful body of workers, upright in character and self-reliant— a source of strength to the country. 10. Life Assurance and Pensions. Democratic conception of government—that it is the duty of the Government to take at the public expense such measures as will give every citizen a chance of working while his strength lasts, and of living in peace when _ work is no longer possible. In time past the poor have heen haunted by the dread of old age, without the power of working, without resources, and without children or friends who might be willing and able to support them. The life of the poor to be set free from this anxiety. ON TRAINING IN CITIZENSHIP. 991 The minimum rate of wages to be such that the wage-earner can live and bring up a family in decent comfort. : ; Life Assurance to be made compulsory when the workman is capable of paying a part of the premium, the State to pay the other part. The duty of advocating and practising thrift. Savings Banks before the War. Causes of pauperism and how to diminish it. Importance of self-dependence and habits of prudence. Honourable dislike of charitable relief among the poor. Dread of the workhouse. Almshouses wholly insufficient in number and not ideal homes for old age. Habit of casting upon Providence blame due to improvidence. Valuable work done by Provident Societies. Irresistible claim of mutilated soldiers and sailors. National Insurance the affair of the Nation. Apart from assurance, the equity of a pension payable to every man or woman who after 70 (or an earlier age) can no longer make provision for himself or herself. Pensions give old people independence, or, if they live with their children, make them no longer unwelcome guests. ‘he pensionable age to be reconsidered in view of the statistics of life. The Government to avoid ill-considered charity. 11. Education. Kducation acknowledged to be the right of every citizen. The Educational Highway. The State not to subvert or impair responsibility for children. ‘La carriére ouverte aux talents’ the true educational object. * Kntire object of true education is to make people not only do the right things but enjoy the right things.’ (Ruskin.) ‘The value of education—influence on character—intelligence—observational power—broad-mindedness—power of self-expression—decision in action— self-reliance—capacity for responsibility. Influence of Public Schools’ games in character training—not confined to Public Schools. Education inefficient if it ends too soon. Mr. Fisher’s Act. Age of compulsory education prolonged. Continuation Schools. Vocational and non-vocational education. ‘Technical education—value to the workers. Higher Education—Secondary Schools—The University. Adult education—School and college only the beginning of the education of the citizen—Study Clubs, Workers’ Educational Association. ‘he Educational curriculum not to be too wide. peers, Risin, Spelling, and Speaking to be taught thoroughly in primary schools. Need of acquaintance with English History and Literature and the possessions and resources of the British Empire. Ancient and Modern Universities. A common educational basis necessary. Evil of premature specialisation. A teacher’s duty to discover and encourage special aptitudes in his pupils. Mitigation in the severity of treatment of children. Discipline—its value—obedience to just rules and orders. “ Nelson’s signal.’ “Loss of the Birkenhead.’ Every oe to feel that his or her success lies in the treatment of difficult pupils. Study of writers upon education—e.g. Pestalozzi, Froebel, Spencer, Montessori. Training and testing of teachers. Character of teacher even more important than advanced literary attainments. Teachers not to look for results _ _ too early. Religious teaching. Advantage of non-sectarian teaching for children in day schools. The co-ordination of different Christian Churches. v2 992 REPORTS ON THE STATE OF SCIENCE.—1920. 12. National Defence. ‘he experience of the Great Wav. No nation safe against unscrupulous aggression unless it is able to defend itself. So great is the debt of every citizen to the State that every citizen may be justly called on in time of need to defend the State. ‘he object of statesmen to be that all citizens should defend the State not compulsorily but voluntarily. Loyalty of Colonies in War. Sea-power not in the future as in the past the determining factor of national life. Submarine vessels and torpedoes. Great Britain no longer an Island. All its past history infiuenced by its isolation. Recent and rapid development of aviation. Command of the air even more important than command of the sea. No nation secure so long as the nations of the world watch each other with jealous, unscrupulous eyes. The League of Nations. Attempt to introduce into public affairs the moral standard of private life and to bring the general sentiment of humanity into play against any one aggressive Power. Information respecting the armed forces of the Crown. No Monarch or Government to make war without the consent of the people. Balance of power to yield place to the law of right, as defined by the majority (presupposing general broad-mindedness and reasoning power). The process of general disarmament. The nation to be strong, but solely for defensive purposes. Problems of national defence to be regularly considered by a committee on Public Safety. 13. The British Empire. The history of the Empire, its creation, the work of the Elizabethan mariners, their names and exploits. Stages in growth of the Empire. (a) Foundation—American colonies in Stuart period. East India Company, 1600. (6) The great quarrel—Loss of American colonies in eighteenth century ; acquisition of Canada, India, and Australia; end of eighteenth century— acquisition of South Africa. (c) Modification in relation of colonies to home country; at first valued mainly as contributing to welfare of home country, and governed from home; gradual grant of self-government (Durham report, 1840, &c.); federation of colonies (Canada, 1867, &c.). (d) Twentieth-century development in organic connection between colonies and home country, or, in a simpler way, (1) That of Elizabeth. (2) That of Cromwell. (3) That of George the Third (really Chatham’s). (4) That of Victoria. The Crown in relation to the Empire. History of the Indian Empire. Present extent of the Empire. Its varieties of peoples and national resources. Value of travelling over the Empire. Children in the schools to learn the dignity of the Empire by the study of © the Union Jack, by the observance of Empire Day, and by the biographies of the men who founded and extended the Empire. z The British Empire is the greatest human institution under Heaven, the greatest secular organisation for good. 5 Principles of the Empire which must never be forgotten or abandoned : ~ (a) Justice, respect of native races for British judicial integrity. (6b) Good i faith, honesty in trade; Honesty the best policy, but honesty not to be = practised because it is the best policy. The word of an Englishman. : ae ne ON TRAINING IN CITIZENSHIP. 993 4 (c) Freedom of speech, of public meeting, of political sentiment, of religious worship. (d) Progress. Government of subject peoples to be always directed to their advancement and improvement—instances of failure, New Zealand in the thirties and South Africa subsequently. 14. National Unity. Citizens in time of peace apt to make too much of divisions and dissensions. Consciousness of unity inspired by the crisis of the Great War. Great Britain, and England itself, a witness to the possibility of fusing different elements, Anglo-Saxon and Norman characteristics. ‘ We are a people et.’ How and why Scotland accepted union with England and made the most of it. Why Anglo-Ivish Parliamentary Union has not been successful. National unity involves the subordination of the party spirit to the good of the whole. All in danger of prosecuting sectional and not national ends. Foreign affairs. Taken, by mutual consent among parties, out of the range of party warfare. The Crown as the centre of national unity. Benefit of a supreme authority which is independent of the vicissitudes of political fortune. Lessons of the War not to be lost in peace. The ideal of national unity to be taught in schools and advocated from pulpits. No hindrance to unity greater than social or political privilege which cannot be overcome; caste a bar to all progress. Glory of Great Britain that the humblest citizen may rise to the highest places. Presidents of the United States, e.g. Lincoln. National unity to be regarded as a means of upholding right. 15. Patriotism. The sentiment natural to civilised humanity. Pride in nationality and national life. Each citizen a member of the Nation and Empire. Spirit of service, sacrifice and sympathy—traditions of achievements in appli- cation of ideals—atmosphere. Children to learn at school patriotic poetry, e.g. Shakespeare and Scott. Value of learning poetry by heart as inspiring noble ideas. Patriotism either false or true. Chauvinism and Jingoism, forms of false patriotism. _ German patriotism before the War both aggressive and immoral, as taking no account of the rights or claims of other nations than Germany. Evil tradition of military power descending from Frederick the Great in Germany. Influence of modern historians, e.g. Treitschke. Issue of the War. _ The collapse of false patrictism. True patriotism recognises an ascending scale of duties from family to city, from city to country, from country to humanity; as the interest of family at times must give way to that of city or country, so must the interest of city or country give way to that of humanity. No patriotism justifiable unless it is such as can be inculcated in all countries without injury to any one country. ‘True patriotism independent of politics. Patriotism and Imperialism—not the same, but often confused. Patriotism, however, not complete without including something of the Imperial spirit. The League of Nations the supreme instrument for moralising international life. ee a be all instructed in the obligation of service to the State. Example of Japan. The Public School spirit which has so signally vindicated itself in the War to be encouraged in all secondary and elementary schools. 294 REPORTS ON THE STATE OF SCIENCE.—1920. 16. Industry and Commerce. Industry the life-blood of a nation, Upon it depend the interest and influence of national life—its value in development of character. But neither industry nor commerce free from danger. The plea ‘Business is business,’ like the plea ‘ War is war,’ may be used to justify evil means and evil ends. No nation secure without trade, yet trade by itself may lower the national standard of duty. Free Trade expresses the natural relation between countries, each country supplying what other countries need and getting in return from them what it needs itself. The world would be happiest if all the world were pacific and all Free Trading. Speeches of Cobden and Bright. But so long as there is danger of one nation attacking another, Free Trade qualified by the necessity of a country being, or so far as possible being made to be, self-supporting. Thus the decay of agriculture might imperil the national safety, as the War has shown. It may be worth while to support agriculture even if the support somewhat raises the price of bread. Value of coal-fields. Change in the character of great industries. Personal relations between employers and employed greatly impaired. Origin of ‘ combines.’ Necessity for restoring a friendly feeling and confidence among all persons engaged in the same industry. Co-partnership and profit-sharing. Arguments for and against the Nationalisation of main industries. Nationalisation not a question of right or wrong, but of expediency; will it tend to the efficiency of the industries nationalised? To be considered from point of view of national, not sectional, interests. True conception of wealth. Adam Smith. Exports and imports. Invisible exports. Increased production the remedy for high prices. Creation of new industries, application of science—electric, gas, dye industries. Without progressive science, labour and capital cannot play their part in modern life. Discouragement of fraud in all relations of life and business. Importance to nation of effective, honest, and intelligent working of all forms of business or industry. Disasters resulting from mismanagement or fraud. The credit attaching to British honesty and thoroughness the chief asset in the British trade. Industrial and social reconstruction. Development of various resources. Co-operation and co-operative societies. Crafts and Industrial Unionism. Arbitration. Wage Boards. Factors deter- mining rates of wages. The living wage. The duty of every member of a Union to abide by its agreements. Industrial Councils. Employers’ Liability, Workmen’s Compensation, Factory Acts. Welfare work. Strikes. Direct action. Guild Socialism. Syndicalism. Duty of community to sympathise with every effort of the workers to improve their conditions and develop their intelligence. 17. International Relations. Nations have historically regarded each other as enemies, but they are really friends. Their interests are reciprocal, if not identical. Different origins of wars between nations, racial, territorial, religious, com- mercial, but all proceeding from the same spirit. The comity of nations an ideal newly acquired or newly realised. The word ‘international’ not found earlier than in Bentham’s writings. ‘International law ’ a misleading phrase, as it implies a sanction which does not exist. ON TRAINING IN CITIZENSHIP. 995 History of the Alabama Case. Mr. Gladstone’s attempt to substitute arbitration for war. Geneva Convention. Hague Conferences. Behaviour of the Powers, especially Germany. Diplomacy. Sir H. Wotton’s definition of an Ambassador. President Wilson’s plea for open diplomacy. The Balance of Power a rude attempt to stave off war by equalising the forces of combatant or rival nations. The League of Nations an attempt to bring the moral senses of civilised humanity to bear upon one offending nation. Appeal of Chili and Argentina to Queen Victoria for arbitration. Statue in memory of the arbitration. Owing to facility of intercommunication the world becoming one family. 18. The Press. History of the Press. Its importance in the present day. Nations no longer hearing but reading nations; hence the decay of the pulpit, and even the platform, in point of influence, but increase in the power of the Press. The Press most powerful in a society in which men and women have learnt to read but not to set a just value upon the news which they read. Newspapers play the most distinctive réle in the enlargement of human nature— a potent weapon in the creating of public opinion, replacing chatter and gossip of earlier periods. Advertisements as a means of success. False credit given to vendors of patent medicines or tipsters in respect of horse-racing. Remedy lies in better education. Responsibility of the Press. Possible misuses of its influence. One danger lies in the control of an individual over many newspapers. Importance of the law against slander or libel. The question whether the publication of false news should not be punishable. Danger of sensationalism. Incorruptibility an honourable feature of the Press in Great Britain. Contrast subsidised newspapers in foreign countries, most of all in Germany. Purity and decency another honourable feature. Freedom of the Press essential to constitutional liberty. Prynne and Cobbett Help given by the Press in the detection of crime. Check to be imposed on reports of divorce and murder cases, as of certain other cases. - Training for a journalistic career. 19. Housing. The homes of the people the sources and centres of virtue. Difficulty of the housing problem. Value of space in slums of great cities. Statistics relating to occupants of single rooms. Morality almost impos- sible where persons of all ages and both sexes are herded together. Cellar dwellings nearly extinct. Need of houses never greater than to-day. The question of housing both physical and moral. Importance of light, space, and sanitation. Municipal authorities now invested with requisite powers. Duty of voters to see that these powers are exercised. Sanitary inspection essential. Owners of insanitary property not to escape responsibility. Rivalry of the home and the public-house. The best counter-attraction to the public-house lies in good private houses. Infantile mortality the result of drinking and of bad housing. Good lighting efficient as a means of lessening crime. Advantage of Garden Cities constructed on scientific principles, e.g. Bourn. ville, Port Sunlight. 296 REPORTS ON THE STATE OF SCIENCE.—1920. Love of home one of the most potent forces in human nature, but impossible unless there are comfortable homes. Need of provision, especially in those parts of Great Britain which are rapidly becoming vast cities. Difficulty of constructing houses for which it is possible to charge a remunera- tive rent. The whole strength of a municipality to be employed under Parliamentary sanction in improving the houses of the poor. 20. Temperance. Drink the greatest national evil. The source of three-fourths of the crime and misery in the nation. Physiological effect of alcohol. Amount of the national bill for drink even during the War. Waste of foodstuffs. No private interest to be allowed to stand in the way of reform. The nation cannot afford to be a drunken nation. Question of the drink trade not local but national. Local option to be the out- come of national control. Local trade and politics. Tied houses. Relation of brewers to publicans. Clubs to be treated like public-houses and beer-houses. Effect of prohibition of vodka in Russia. Prohibition in U.S.A. Not so much a social as an industrial measure. A guarantee for industrial efficiency. Estimated to increase efficiency by 10 per cent. Two influences making for temperance: (1) Women’s votes, (2) Education in elementary schools. Work of the Central Liquor Control Board during the War. Similar, if not the same, control necessary in peace. Nationalisation or State purchase of the liquor trade. Argument for nationalisation. So jong as private interest in the sale of liquor exists, the State is exposed to inevitable danger. Take away motive of self-interest and improvement will become possible. The late Earl Grey’s project of disinterested management. Owners of public-houses to be made responsible for’drunkenness occurring in them. Duty of State to remove temptation as far as possible from citizens. Gain of excluding children from public-houses. In the present rivalries of the nations, Great Britain must become sober, or it will lose its pride of place. Temperance societies and their campaign for national sobriety. 21. Leisure and Recreation. Daily life and its division into working, leisure, and sleeping periods. Necessity for useful and strenuous work as opposed to slothfulness, idleness, and luxury. Pres of idleness and luxury. Gossiping. Street-corner and public-house idlers. The danger of morbid introspection. The influence of habit upon development. Many persons ruined through inability to employ non-working periods proper!y. Importance of proper amount and kind of recreation. Change from, and foil to, work. Suitable recreation for manual workers, sedentary workers, and brain-workers. Demand for more leisure-time from physical work. Leisure-time not to be wasted in idleness but to be profitably occupied in neces- sary rest, home duties, civic duties, amusements, and self-development. Due proportion of leisure-time to be given to self-improvement or self-develop- ment. Self-development—hobbies—literature—music—art, &c. Adequate provision of facilities—libraries, &c. xz ad a ete ON TRAINING IN CITIZENSHIP. 297 | Amusements of the people: (1) Old-time : Morality plays, mummers, strolling players, revels, fairs, morris dancers, May Day. (2) Present time: Pro- cessions, sports, regattas, racing, picture palaces, theatres and music-halls, athletics, &c. The habit of looking at, as opposed to taking part in, sports. Provision of open spaces in towns. Enjoyment of open air and interest in natural history. Games and their value in the development of esprit de corps, co-operation, responsibility, perseverance, emulation, fair play, leadership, discipline. Team-games for children. Importance of organisation and supervision of games at school. The evil of gambling—its effects upon sports. Provision of play-grounds and playing-fields. Boy Scouts. Girl Guides. The proper use of holidays. Summer camps and schools. Co-operative holidays and tours. Juvenile organisations, Committees. School clubs. 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Games Captain . . : t : . green rosette, red centre and edging. Games Sub-Captain . . Ha Hag . red rosette, green centre and edging. Assembly Sergeants. c ‘ d . red disc, blue centre. | Assembly Corporals F : i s . yellow disc, black centre. Assembly Lance-Corporals . t ; . green disc, red centre. ‘Crack’ Sergeant and Corporal . 3 . ved ribbon. ON TRAINING IN CITIZENSHIP. 809 Qualified by examination as N.C.O.s.—These are entitled to wear a green ribbon. The Secretary is responsible for collection of the badges and their redistribu- tion at the proper times, and must in particular see that the badges of Prefects who are absent do not get lost. Prefects are not entitled to any of the privileges or immunities attached to prefectship unless they are wearing their badges of rank. CowLey ScuHoots, Sr. HELens. Civic Government by Boys. (Written by a Boy at School.) There is at Cowley a system of self-government by the boys, whereby every boy of average intellect is given a chance of commanding his smaller school-fellows. Description of System. School of 300 divided into 8 houses, and forms as usual. Each house has a captain, a vice-captain, and a house-master, in addition to house-prefects. Inter-house competitions take place between houses in Rugby, cricket, box- ing, swimming, and work. To each of the champion houses there are cups awarded. The school itself has about eight prefects and eight sub-prefects, who have a private room of their own. These are led by a head-prefect. The games in the school are compulsory, and take place after 4.15 on Monday, Tuesday, Thursday, and Friday, and also on Wednesday afternoon. On Monday, Tuesday, Thursday, and Friday, for twenty minutes after 12 o’clock, the school does ‘drill,’ not physical (takes place under tutorship of master) but military. It is an actual fact in this school that the ‘boys’ do self-govern and masters are in the school only to teach in certain periods. Why are the boys able to do this?’ For the following reasons :— Spirit of Command is fostered. (a) Captains of Forms are responsible for their forms, and as form matches take place between forms the captain has ample scope of the exercising of his authority. (6) The games are run in sets. Every set has two or three captains, and almost every boy in the school has a chance of captaining a side in Rugby or some other game at some time or other. (c) As a boy grows older, having had practice as a form or set captain, he becomes, perhaps, if he shows energy, vice-captain and the captain of a house. This means work and plenty of it. When a boy becomes a house-captain he begins to understand the spirit of responsibility. (d) Minor and then chief commanding position in drill.—This point cannot be too greatly emphasised. It is a well-known fact that chaps in this school hate military drill until they obtain a minor command. This enlivens their interest, and the worst grouser after a year of commanding realises the value of the drill—not for its military value, but for the effect it has on one’s personality. A boy afraid to enter a room containing a master may come out so much in a year by commanding a squad in the drill that a whole squad of masters would not and do not frighten him. (e) After these preliminary steps to the top a boy becomes first a sub- prefect and then a prefect, a captain of games (either Rugby or cricket) or a chief commander in the drill. In this way the spirit of command is fostered and a boy leaves Cowley fit to tule a kingdom (as well as the Coalition do England). A prefect may give a boy lines, he may, in special cases, whack a boy, but what backing does the prefect get from the powers that be? (a) The Head supports him. (6) The masters tolerate him. _ (¢) The governors don’t know what he is and will not admit his rights. 810 REPORTS ON THE STATE OF SCIENCE.—1920. Still the Head’s power goes a long way, and it is very few foolish parents who seriously object to the prefect system. (In one or two cases only each year is a boy beyond the control of prefects.) The pretect’s chief weapon at Cowley is public opinion : This shows out most clearly in the houses. A boy transgresses (fumbles a ball in a house match or some other terrible thing). The house-captain appeals to the house. Is the boy worthy of a whacking? The house decides—the boy is whacked. All the parent can say against this system is that the house are bullies, but can forty boys be all bullies? The house whackings are, therefore, in most cases fair, and become, as has already been said, the prefect’s chief weapon. Public opinion : Some prefects are liked very much—others are tolerated. Some are disliked. It is safe to say that most prefects are not disliked, and if a prefect is not disliked then public opinion helps him. Duties of a prefect : With these weapons a Cowley prefect sallies forth. No master challenges his right. Masters teach and disappear. The prefects go in lessons and then appear for duty in keeping the school in order, in arranging games, &c. But no master interferes. Not even a house-master has much power in his own house. A Cowley prefect has no masters to rival his authority. He can give lines and whack (Only me! T.B.) (when backed by public opinion or in special cases). A boy, with the help of set captains, through the school, manages the games. The prefects manage the drill (alone). Do not the prefects then rule the school, and, as public opinion either supports or does not support a prefect, then is not the school self-governed by the boys? PrenaRgtH County ScHoot ror Griris, WALES. (Written by a Girl at School.) The aim of self-government in school is an attempt to train the child as a. responsible citizen without taking away his delight in childish things. It is an attempt to train him to be that type of child who will later on in life be a. self-respecting, responsible citizen, and, as such, it includes the true purpose: of education. It is impossible for any man or woman to be capable of controlling even a local committee if he has not been trained to think for himself and act as a. responsible member of society. If children are not made to think for them- selves, if teachers and parents insist on doing all the directing and thinking for them, they cannot expect that the child, when he grows up, will be capable of looking after himself and his fellow-men. It is difficult in an ordinary county school to carry on self-government to a great extent, because external examinations demand so much time, and there is a certain amount of work to be got through in a limited time. And the space and means at the disposal of the Head-mistress are so limited that it needs clever organising to be able to stray from the beaten track, but there is a certain amount of experimenting possible even in the busiest school. Practically all that we have done originated in our English Composition lessons, but to give a definite account of the gradual growth of self-government in school is impossible. In IV.¢ and IV.8 there is a Form Committee which is elected by the form to manage all matters connected with the form. The III., V.8, and V.4 have themselves arranged a programme of English Composition lessons for this term, and every form has a chairman who is pre- pared to take the class and direct affairs at any moment. The lessons are varied and are all such as will increase the pupils’ knowledge of and command over the English language and literature, and will give them confidence to act on their own initiative. It is significant that the younger girls soon got over their shyness of facing a class and being called upon to give an ‘Oral Com- position,’ but that older girls, who when working for examinations had little ON TRAINING IN CITIZENSHIP. 311 time to spare, afterwards when they tried took far longer to get used to the idea, and their attempts were often feeble. ; It gradually became felt that something ought to be done to bring the scattered committees together, and with the guiding help of the staff the idea of a Girls’ Representative Council was thought of. It was decided that the Council should be formed consisting of the secre- taries of the different committees and a form representative from every form, except the two lowest forms. The voting for Secretaries and Representatives was done by ballot by the whole school, with the head girl, chosen by Miss Lloyd, as President. The Council sat for the first time in September 1919 and meets on an average once amonth. As the Girls’ Representatives they carry out as far as possible all new ideas and desires of the girls which have received the Head-mistress’s sanc- tion, They act entirely on their own responsibility and as a rule are successful. The last Prize-giving was practically all the work of the girls. One of the most important features is the General Knowledge Club. Any girl from IV.c upwards may belong, and it is held weekly. At the beginning papers were read by courageous individuals on varying subjects. Lately whole forms have combined to give a form entertainment. At the end of last term Miss Lloyd asked the Council if they felt prepared to take the responsibility of looking after a blind girl in school. The whole Council agreed that it would be good for the girls to look after somebody who lacked something they all enjoyed, and they appointed a Committee to arrange her lessons, &c. The girls have been, if anything, too kind, but now they seem to be realising that it will be kinder to show her how to get about school on her own, rather than that they should take her. This training is excellent for the girls, for no one can be a good citizen unless he is gentle and courteous to those older or weaker than himself. Roatu ParK Boys’ ScHoot. Prefect System. The Prefect system has been in use for seven years and has passed altogether out of the experimental stage. It has proved its great value :— 1. In developing a sense of responsibility. 2. In training boys to lead and manage others. 3. In improving the tone of the school. Duties of prefects : 1. The head-prefect has a general supervision over the work of the other prefects. 2. The other prefects take entire charge of (a) Bell-ringing. (6) Letters for staff. (c) The lavatories, towels, soap. (d) Latrines (regularly inspected). (e) The stairs during entrance and dismissal. (f) Lost and found articles. (g) Late comers (lateness nearly stamped out by the system). 3. On rainy days, during interval, the prefects take charge of classes. Self-government : Prefects, with help of teacher, elect to vacancies, and also elect their own head-prefect. Offences committed by boys are reported to head-prefect, who investigates, and reports, if necessary, to teacher of offender. If case is serious, to Head- master. Inattention to duties on the part of, or offences committed by, prefects, are, first of all, investigated by a ‘tribunal’ of prefects. If case is proved, the offender is admonished by the head-prefect. Serious cases are reported to the Head-master. 812 REPORTS ON THE STATE OF SCIENCE.—1920. Scout-craft. For two years, 1916-18, one hour per week of the school time-table was devoted to scout-craft. Boys were trained and drafted into regular troops. The advantages of working as a preparatory organisation for feeding other troops instead of running a regular school troop are :— 1. Boys over 14 years of age could continue as members of the troops they join, and so avoid the ‘break’ when leaving school. 2. Most of the better boys of the school leave for secondary schools, and could continue scout-training only as members of regular troops. 3. A troop run as part of school-work would always be associated with ‘com- pulsion.’ Objects of system : 1. To develop character, work, self-training. 2. To counteract ‘ cinemas,’ discourage idleness and thriftlessness. 3. To interest boys in Boy Scout and Boys’ Brigade organisations. 4. To draft boys into local troops. Membership : 1. Any boy in Standard V. and upwards may be a candidate. 2. He is admitted after one month’s home-work as a ‘test.’ Method : I. Weekly meeting of one hour for instruction, including : 1. Talks on lines of Scout yarns. 2. Preliminary tests for Tenderfoot badge. 3. Talks on troops in Cardiff. 4. Practical work, such as (a) Knot-making ; (b) Flag-sketching ; (c) Signalling ; (d) Map-reading ; (e) Use of the compass. 5. In most cases the leader of each patrol was responsible for training the boys in his section. II. Patrols. . There were six patrols—A, B, C, D, EK, F. . Each patrol had its leader, second, third, &c. . Leaders and seconds acted as school prefects. . Each boy had a note-book (ordinary exercise book) in which he kept a record of work done at home. . The books were marked by the leaders. . In addition to ordinary school-work the following were accepted as -satisfactory ‘home’ work : (a) Model-making ; (b) Sketching ; (c) Hobbies; (ad) Choir-practice ; (e) Music lessons ; (f) Attendances at churches; (g) Attendances at Scout or other organisations. oO or ee Tur Hicu ScHoon or Guascow. Extract from Prospectus for 1914-15. Prefects. Prefects are divided into two classes—Form and School. 1 Each Form ‘has two prefects, one chosen by the master, the other by the — Form, subject to the veto of the master. These should be boys who have most distinguished themselves for public spirit. In consultation with the master they are responsible for— 1. The efficient government of the Form in the master’s absence. 2 The general welfare of the Form. They will be under the command of the school prefects for police duty. Se 4 ae ON TRAINING IN CITIZENSHIP. 813 School prefects are appointed by the Rector. They are divided as follows : The Captain; the Lieutenant; four Buildings Sergeants; four Privates. The captain of the school is ex officio head of the games. Disobedience to a prefect’s order is an offence against school discipline. ‘ wh The duty of a prefect is to see that the welfare of the school is maintained. The purpose of this class is the gaining of an intelligent acquaintance with the facts connected with our system of government, both local and imperial, and with the rights and duties devolving on a citizen. It is intended primarily for those just leaving school, and it forms a valuable introduction to the study of economics and industrial history :— Methods of election of various governing bodies; powers and duties of Parish, County, and Town Councils; Local Government; Education, Poor Law, Public Health, Licensing, and Harbour Authorities; judicial and financial systems, local and national; election of a member of Parliament; the Party system; the Cabinet and the Departments of the Executive Government; Governments within the British Empire; relations with Foreign States. APPENDIX V. Suggestions for Organising Regional Study and Maintaining a Permanent Regional Record in a Parish, (By the Karl of Lytton.) I. Objects to be aimed at. 1. To prepare and keep up to date a complete historical survey and history of the area. 2. To establish a local Regional Museum illustrative of the survey. 3. To secure the maximum educational advantages from the work. 4. To enlist the services of the children in the work, thus helping to train their observation, stimulate their interest in their surroundings, and develop their faculties. 5. To make the school and its work a centre of interest to all who live in the neighbourhood. 6. To secure co-operation between the teachers, the children, and the adult population. II. Steps should be taken to : . Hold a meeting for the discussion of the subject. . Form a Regional Association for the study of the parish. . The school to be recognised as the Regional Museum of the parish. . Enlist the interest and co-operation of the teachers and children of the school. . The survey and record to be kept at the school; the teachers and older children to become the first members. . Secure the interest and co-operation of the local Boy Scouts or any other local organisation. . All members of the Association will be expected to keep notes of any observa- tions they may make and give them to the school to be incorporated in the central record. 8. Members will also be expected to present to the school museum any articles of interest they may find, such as flint implements, pottery, coins, fossils, &c., also contemporary objects of local historical interest. 9. Members will also be expected to assist in the preparation of historical records of any old buildings in the parish and in supplying information about the houses which they occupy, as well as in keeping the annual record up to date. 10. It is further hoped that members will help to provide in the school books of reference on natural history or archeological matters, materials for exhibit cases, &c., to be made by the children, illustrations in the form of photographs or pictures of matters of local interest. They can also elp by giving facilities to the children to make observations on their property by assisting them to pay periodical visits to local museums and by lending books or objects for any special branch of study. “I for] of WN 814 REPORTS ON THE STATE OF SCIENCE.—1920. III. Things which in course of time the school should contain. 1. A map of the parish, or area to be surveyed, on which every field, hedgerow, road, lane, wood, river, pond, or house should be given a distinctive number, and its separate name, where these can be ascertained. 2. A permanent register or record of the past history of every place in the area, and of every fact which can be observed concerning the life of these places year by year, under their distinctive names and numbers, &c.—e.g. changes of property, rotation of crops, habits of animals, arrivals and departures of migrants, striking weather conditions, &c. 3. A series of traced maps showing separately— (a) The geology. (6) The vegetation. (c) The water supply. 4. A summarised history of all ancient buildings and monuments, and a biblio- graphy of books referring to them. 5. A brief description of every modern building, containing the date of its con- struction, alterations, and the names of the families occupying it. 6. A classified list of all animals, birds, butterflies, moths, insects, trees, shrubs, plants, and wild flowers found in the area. 7. Specimens of any articles of historical interest, whether ancient or con- temporary, found in the area. 8. Illustrations of local plant and animal life, or, if desired, actual specimens of birds, nests, eggs, butterflies, moths, &c. If such specimens are collected they must be properly preserved, mounted, and catalogued. 9. A list as complete as possible of Lords of the Manor, Rectors of the parish, Ministers of other denominations, Head Teachers of the school, Parish Councillors, distinguished natives of the parish, &c. 10. The record of the activities of the parish in the Great War 1914-1918, or in any other period of special interest. APPENDIX VI. Suggestions for Local Survey for Town Schools. (By Valentine Bell.) The environment of the child plays such an important part in its education that it is of the utmost importance that the school should be brought into closer touch with the school district. The school should not be a cloister. One of the first points to be driven home in the training of teachers should be that a teacher cannot become a really successful influence unless he or she is thoroughly acquainted with the school district. Local surveys are the best practical means of teaching live citizenship. Other advantages of survey work are palpable to any teacher. Teachers should take advantage of the stores of information at the Town Hall, Public Library, local museum, and local Societies (Archeological, Botanical, Photographic, &c.). In most towns valuable information, e.g. old prints, plans, maps, &c., is stored away in local libraries and museums, and is rarely ever asked for. Local surveys can well be taken if the locality is made the means of approach to the education of the child. The Geography Lesson.—Physical features, means of communication, indus- tries, population, &c. The History Lesson.—The old manors; the old views and maps of the district ; the pastimes; the evolution of the means of travelling; old toll-gates; old buildings (manor-house, church, castle, abbey, gates, inns, &c.); the punish- ment of crime (police-stations, old watch-house) ; public-house and street names ; old industries, &c. 5 The Drawing Lesson.—Sketches of objects connected with locality (indus- tries, &c.); details of old church, castle, &. (Norman, Gothic, and Tudor arches, tiles, &c.); pictures from history books; flowers in locality, &c. The Writing and Composition Lesson.—Examples of local interest, ey ON TRAINING IN CITIZENSHIP. 815 The Literature Lesson.—Interest should be aroused in the work of celebrities -connected with the district by birth or residence. Local memorials, as statues or tablets, are frequently unknown by the inhabitants. The Arithmetic Lesson.—This lesson can be made most practical when approached locally. Exercises on the park (areas) ; local shopping centres (com- pound rates); the river; the industries; Report of M.O. of Health (practical percentages, decimals, and graphs), &c. The Science and Nature Study Lesson.—In elementary schools children should have the phenomena that surround them explained (vide Board cf Education latest circular). Lessons.—Why doesn’t a factory chimney fall? Why are water-tanks often above the roofs? How does a motor-bus go? Why do we get gravel here, chalk there, &c.? The dispersal of seeds of local plants, &c. Lollard Street L.C.C. School, N. Lambeth. Class Work (in most cases taken after Outdoor Work). . The Ordnance Map of the district (explanation of conventional signs, &c.). . The district as viewed from some ‘outdoor tower’ (top floor of school, summit of local hill, &c.), and directions driven home with use of the map. Important buildings noted, e.g. churches, factories, gasometers, &c. . The Physical Features of the district. (In crowded areas, the district before the houses. Map to be made.) . The Simple Geology of the district. (Digging operations for sewers, &c.’; sections of local borings for wells.) . The Botany of the district. (In crowded areas, the vegetation in local parks and other open spaces is of great interest.) . The Growth of the district as traced from old maps. (The manors; the old houses marked on modern map. The influence of railway, trams, or new "bus route can be seen.) 7. A chat on old views of the district. (Often of value in discussing No. 3.) 8. The Parish Registers and what they teach us. 9. The Streets. (Street names. Style of house; when built.) 10. The Public-houses. (Value of names. The Breweries.) 11. The Amusements of the district. (Cricket, football, &. Comparison with Amusements of our forefathers. The revival of old dances.) 12. The Good and Bad Influences at work in the district. (Picture Palaces, Public-houses, Recreation-grounds, Home-gardening, Churches, Scouts, Bands of Hope, Polytechnics, &c.) 13. The Means of Communication in the district. (Railways, "buses, tubes, trams, canals, &c. Suggestions for improvement.) 14. The Open Spaces and Recreation-grounds. (Various features compared, &c.) 15. The Local Industries. (Decayed, decaying, and modern. Causes of growth and decay. 16. The Important Buildings. (Town Hall, Library, Public Baths, Churches, &c.) 17. The Local Authorities (work of Borough Council, Board of Guardians, Police Authority, &c.). 18, The Feeding of the locality. (Markets, Milk Supply, &c.) 19. The Health of the district. (Report of M.O.H., Graphs of Birth and Death Rates, &c.) Architectural Development : Lambeth Palace. Lambeth Church. Eighteenth and early nineteenth cen- tury houses. The Amusements of the People : Survey of Local Amusements. Sports. Kennington Oval. Open spaces. Picture Palaces; Music Halls; Public-houses; the Old Pleasure Gardens; Vauxhall Gardens; Duck-shooting in Lambeth Marsh; the last London Maypole; the Regatta—old University Course from Westminster to Putney. The Fight against Disease : Report of Medical Officer of Health. Old Parish Registers. Survey of Hospitals, Dispensaries, and Medical Missions. _ Local Government : Survey of Lambeth’s Local Authorities. The Old Church Vestry—Old Vestry Hall—Old and New Town Halls. NH a oOo - Ww 316 REPORTS ON THE STATE OF SCIENCE.—1920. History for Four Upper Classes. The classes will make a survey of the school district and by means of this approach an elementary knowledge of the social and industrial history of England will be attempted. Introductory Lessons : (a) The Scroll of History. (6) The Centuries. (c) Leading Dates. The Britons : Local Items.—Lambeth before the Houses. Boadicea’s statue. The Romans : The Old Kent Road. The Roman Boat found when digging the County Hall foundations. Stangate. The Roman Bath in the Strand. The Land : Local notice-boards advertising sites for sale. Local examples of Freehold, Copyhold, and Leasehold. Local entries in Domesday Book. The increased value of Pedlar’s Acre (site of County Hall). Notice summon- ing General Court Baron for the Manor of Kennington. Enclosure of Lambeth Green. The Growth of Towns : The 1593, 1750, 1797, 1820, and 1870 maps of Lambeth. Old views of Lambeth. The Growth of Industries : The present and past industries of Lambeth. Survey of local trade unions and friendly societies. What we owe to Foreigners : The introduction of glass- and pottery-making into Lambeth (Venetians and Dutch). The Evolution of the Means of Travelling : Survey of Lambeth’s means of communication. The railways, tubes, trams, ’buses, taxi-cabs, motors, &c. The Brighton Road via Kennington Gate. The old inns. The Punishment of Crime: The police-station. Lambeth Police Court. The Old Watch-house in High Street. The old Surrey Gallows at Kennington. The Religious Life of the People : Survey of the various local churches and chapels, &c. Lambeth Palace. Bunyan’s Hall. The Growth of Education : Survey of local schools, evening institutes, polytechnics, colleges, &c. Lambeth parochial school (Archbishop Temple’s). The Tradescants and Elias Ashmole. ON TRAINING IN CITIZENSHIP. 317 British qe CLERKENWELL Museum Smithfield De) ONIEYHD > 2 “a> > “ 2) A RTINS L i) 2 o gw Lollard St School SHOREDITCH Places for Educational Visits. Lambeth Palace. The Temple. Tate Gallery. Westminster Abbey. National Gallery. St. Margaret’s Church. National Portrait Gallery. St. Paul’s Cathedral. British Museum. Southwark Cathedral. Find the nearest and cheapest way of reaching the above. St. Bartholomew the Great. The Guildhall. The Tower. Houses of Parliament. Study the tram map. 318 REPORTS ON THE STATE OF SCIENCE.—1920. VISIT TO WESTMINSTER ABBEY. Lollard S* School Write down the Route we shall follow. Points of interest to be noted. Georgian Houses in Pratt Street. View of Lambeth Palace from Archbishop’s Park. Old Village Houses in Park Place. Names of Public-houses in and near Paris Street. The views up and down the river from Westminster Bridge. The statues in Parliament Square. The dwarfing of St. Margaret’s by the Abbey. The link-extinguishers in Dean’s Yard. The view of Lambeth from Millbank, The Toll-house on Lambeth Bridge. Kinds of Questions to ask Yourselves :— Why is Juxon Street so named? Who controls the Archbishop’s Park? Who built Lambeth Palace ? When were the Embankments constructed ? Who is responsible for the upkeep of Westminster Bridge? ON TRAINING IN CITIZENSHIP. 819 ROUGH PLAN OF WESTMINSTER ABBEY. WESTERN OOOoR JERUSALEM CHAMBER COLLEGE DEANERY EAST CLOISTER Ne Dimensions. Length, with Henry VII.’s Chapel, 513 ft. Length of transepts: 200 ft. Height of towers: 225 ft. Height of Church: 102 ft. Find in dictionary the meanings of the following :— Aisle, nave, sanctuary, ambulatory, cloister, transept, vestibule, deanery, chapter, pyx. Find out any other terms used in architecture. Draw a simple sketch illustrating a Norman and a Gothic arch. 320°: REPORTS ON THE STATE OF SOIENCE.—1920. VISIT TO THE TOWER OF LONDON. 1. Name our route and the buildings marked. 2. What tram services run through the Obelisk and the Elephant and Castle? 3. What bridges can be seen from London Bridge? In what ways are the banks of the Thames at London Bridge different from those at Lambeth Bridge? 4. What steamships did you notice? What flags were flying? What evidences existed in the Pool of the war being on? 5. Where was the Fishmongers’ Hall? What is it? How do you account for its site? 6. What particularly struck you in Lower Thames Street? Name some of the public-houses. What type of shop was open? 7. Describe the dress of a Billingsgate fish-porter. 8. Draw a rough plan of the Tower of London, marking the Moat, Inner and Outer Bailey, and the Keep. 9. What are the following: The arquebus, matchlock, flintlock, mace, lance, stink-pot, rack, scavenger’s daughter, visor, pike, chain-shot, grape-shot, halberd ? 10. Describe briefly the historical growth of the Tower. 11. Name any notable folk connected with the Tower. 12. In what Tower are the Crown Jewels guarded? Explain K.G., K.T., K.P., V.C., D.8.0., G.C.B., K.C.M.G., G.C.S.1I., C.V.O. 13. What regiments were stationed at the Tower? Describe the dress of a ‘ Beefeater.’ ON HARMONIC PREDICTION OF TIDES. 321 Tidal Institute at Liverpool.—Report of Committee (Prof. H. Lamp, Chairman, Dr. A. T. Doopson, Secretary, Sir 8. G. Burrarp, Sir C. F. Cross, Dr. P. H. Cowstn, Sir H. Darwin, Dr. G. H. Fow.uer, Admiral F. C. Learmonts, Sir J. E. Peraven, Prof. J. ProupMaN, Major G. I. Taytor, Prof. D’Arcy W. THompson, Sir J. J. Toomson, Prof. H. H. Turner). 1. Report on Harmonic Prediction of Tides. By A. T. Doopson, D.Sc. THE present state of harmonic prediction of tides cannot be regarded as very satis- factory, and this report has been written with the object of calling attention to the matter. For some of the information the writer is indebted to the Hydrographic Department of the Admiralty. While real accuracy in the prediction of tides is not obtainable at present, owing to inability to predict effects of meteorological variations, yet one would expect that the normal, or undisturbed, or periodic tide could be accurately given. That such is not the case is well known to those who have compared observations with pre- dictions ; there are periodic or systematic differences in height and time of high water which are sufficiently serious in many cases to cause distrust. This is especially the case with harbours in river estuaries or in comparatively shallow seas, and, in fact, the distrust has led in many cases to the complete abandonment of the method of harmonic prediction. Thus the Hydrographic Department of the Admiralty report that the German and Netherlands tidal authorities have found the methods of harmonic prediction so seriously in error that they have abandoned them, and the experience of the Hydrographic Department for the North Sea has also been very unfavourable to the continuance of this method. For many ports situated in estuaries, and catered for by British authorities, it is customary to apply non-harmonic corrections to the results of harmonic prediction. It is generally admitted, however, that harmonic predictions for oceanic ports (i.e., ports open to the free influence of the deep water oceanic tide wave) reach a high degree of accuracy. The general continuance of the harmonic method of prediction, therefore, will depend very largely upon the solution of the ‘shallow- water problem.’ This calls for scientific research, and, concerning it, reference may be made to future reports of the Committee. That the method of harmonic prediction for river ports should be in danger of discontinuance could be taken as sufficient evidence regarding the unsatisfactory state of harmonic prediction, but a few figures may serve to show what degree of inac- curacy is considered by authorities to be unsatisfactory. For instance, at Quebec the average error, regardless of sign, is as high as 16 minutes for high water, and _ 28 minutes for low water predictions, though the harmonic constants for Quebec are based on over 19 years’ continuous observation. Again, a comparison of observa- tions with predictions of high water at Liverpool shows a very marked oscillation in the differences, of which the following is an example :— 10, 6, 11, 3, 9, 4, 18, —1, 8, —7, 8, 2, 8, 2, inches ; thus successive high waters are alternately predicted too low or too high by as much as seven inches. (The predictions are taken from the tables of 1918, It should be stated, however, that these are not purely harmenic predictions, but are corrected by non-harmonic methods.) This is probably due to incomplete or faulty analysis, and, concerning this, reference may be made to Prof. Proudman’s Report on Harmonic Analysis, where comparisons between observation and prediction of hourly heights are recorded for Liverpool, 1869; it has been shown that this represents also the present day state. If, however, the above evidence were not available an estimate of the value of 1920 Y 822 REPORTS ON THE STATE OF SCIENCE.—1920. harmonic prediction could be obtained from comparisons of the predictions made independently for the Admiralty and by the United States Coast and Geodetic Survey. One would naturally expect that predictions ostensibly obtained from the same harmonic constants would be fairly concordant, even if slightly different mean values were used, and that the lengthier the series of observations and analyses the better would be the correspondence in prediction. But an examination of the independent predictions shows that this is not so. The following table was prepared by taking one month’s predictions from the Admiralty tables and comparing with the corresponding predictions published in the United States tables. The maximum difference and average difference, taken without regard to sign, are given. for the heights and times of high and low waters. Number Mean a8 Times Port of years | range of | Greatest : : Average | Greatest | Average analysed |spring tide) aiterence | difference difference | difference feet inches inches mins, mins, Liverpool. . . | 7orover) 28 11 5 21 10 St. John, N.B. . |15 ,, ,, 23 12 3 16 4 Bombays «= i \1 (soe 15 if 14 32 4 Adeninoasrq 44 old leiaida,; 7 5 16 30 8 Wellington . . | 2 4 7 2°5 34 16 Balboa. .oos >. | -1 16 3 1:2 34 10 In the case of Aden, the range of tides on certain days is small, so that the time. of high and low water is uncertain ; these days have been ignored. The above table in itself bears testimony to the unsatisfactory state of harmonic prediction, even if we had no further evidence. We are not at the moment con- cerned with the cause of any discrepancy between the two independent predictions so much as with the general results. Where, as in the case of Liverpool, we may have two different predictions, each supposed to be authoritative, which differ occasionally by nearly a foot and on an average by five inches in height, then one’s confidence in the accuracy of prediction is badly shaken. The differences in times. are also serious and are considered so by all authorities ; these provide the best test of the accuracy of prediction in all cases, since the height differences are naturally small when the mean range of spring tides is small, While the maximum and average differences are conclusive, there is also much interest in a fuller examination of the differences that do occur. It is found that there are periodic differences of some magnitude in practically all cases. For Liverpool, on certain days both high waters have a positive difference and both low waters a negative difference; that is, there is a semi-diurnal oscillation (in the differences), of which the amplitude is about seven inches; moreover, there are diurnal oscillations also present in the differences, as is shown by one set of high- water differences being consistently lower than the alternate set, e.g. 4, 8,0, 4, —4, -1, —7, —3 inches. Similar results are found in the differences in times of high and low water. As another example, in the case of St. John, N.B., there is a semi-diurnal oscillation of nearly a foot on certain days, as is shown by the following series of differences in heights for successive high and low waters :— —7, 12, —12,11, —8, 12, —11, 12 inches. The effects vary with different machines, but, generally speaking, for all the ports there are systematic differences which should not be allowable. Enough evidence has now been given to show why it is considered that harmonic predictions are not at present satisfactory ; two independent methods of judging them have been considered, the first being based upon the experience of tidal authorities in comparing predictions with observation, and the second being based upon the disagreements that exist between two sets of predictions calculated inde- pendently of one another. ON HARMONIC PREDICTION OF TIDES. 323 It is quite certain that the chief cause for the failure of harmonic methods for shallow-water ports has been the incompleteness of analysis, and the absence of a reliable method of dealing with the shallow-water constituents. This is under investigation. , Regarding the differences in predictions, it is necessary to consider four possible causes: (1) differences in the values of harmonic constants used by the two authorities furnishing the predictions, (2) differences in the number of harmonic constituents that can be taken into account on the machines used for the calculation, (8) application of corrections, as at Liverpool, (4) uncertainty in the behaviour of machines. It will be admitted that the choice of harmonic ‘ constants’ that can be made ought not to bea serious matter, especially where there are lengthy series of observations, as in the first four examples quoted. In the case of Balboa, it is believed that the harmonic constants used are identi- cal, and that no corrections have been made to the machine results, so that one seems driven to assign the fourth cause. There is evidence from other sources which tends in some cases to throw a certain amount of doubt on the behaviour of predicting machines, but this also is under investigation by the Committee. The machines used for the purpose of predicting tides differ considerably in the number of constituents that can be taken into account, but it is not much palliation even to know that a machine is as accurate as it can possibly be, when important constituents have necessarily to be treated as non-existent. Investigations at the Tidal Institute point to the conclusion that the number of constituents required to deal adequately with the shallow-water problem is considerably greater than that allowed for in the building of tide-predicting machines: It is partly for this reason that corrections by non-harmonic methods are sometimes applied, though their success is very doubtful. The whole problem of the harmonic prediction of tides is being investigated by the Committee, in collaboration with the Liverpool Tidal Institute and other bodies interested in tidal work, and further information concerning progress will be presented in their reports to the Association, 2. Report on Harmonic Analysis of Tidal Observations in the British Empire. By J. PRouDMAN. 1. The following report was undertaken for the Association through Prof. Lamb, who has collected information from all the authorities concerned, and has been in consultation with the author during the whole time of its preparation. It is based on information very kindly supplied by the Admiralty, the National Physical Laboratory, Messrs. Roberts, Prof. D’Arcy Thompson, the Survey of India, the Tidal Survey of Canada, Prof. R. W. Chapman of Adelaide, the Government Astronomer of Western Australia, and the Tidal Survey of New Zealand, as well as on the published literature of the subject. In the first place an indication is given of the origin of the various harmonic constituents, which aims at explaining more than the customary popular accounts, while avoiding the heavy mathematical formulz required for the analysis itself. In the second place a table is given of the results of analysis, the inconsistencies in which show that the subject is in an unsatisfactory state. In the next place an account is given of the various methods of analysis that have been used hitherto, with the object of making prominent their essential features, and providing the basis of a critical examination of them. To complete this critical examination requires a large amount of computative labour. Finally, a complete historical account is given, with bibliographies and lists of analyses made. It is to be remarked that the principle of the harmonic analysis is part of the theory of the gmall oscillations of a dynamical system, and its application becomes less accurate as the range of tide becomes a larger fraction of the depth of the water, or as the tidal currents become greater. It yet remains to be found to what Y¥2 824 REPORTS ON THE STATE OF SCIENCE.-—1920. precise extent the purely astronomical tide at any station may be expressed as a series of a reasonable number of harmonic constituents. When this has been done and the methods of analysis and prediction refined so as to give predictions correct to this extent, a hopeful investigation may be made into the residual astronomical tide and the whole of the meteorological disturbance. In a preliminary report * presented to the Geophysical Discussion of June 1918, it was stated that tide tables as at present produced appear to be adequate for practical needs. ‘This was based on the facts that the practically important constituents can be determined fairly accurately, and that harmonic prediction presents no theoretical difficulties like those of harmonic analysis. The investiga- tions of Dr. A. T. Doodson show, however, that the published tables of harmonic predictions are also very unsatisfactory. Harmonic Tidal Constituents. 2. The gravitational forces generating the tides are derivable from a potential which is everywhere proportional to what the height of the tide would be if water covered the whole earth and had lost its inertia without losing its gravitational properties. Such a tide—the equilibrium tide—may be calculated by adding the amounts by which a certain pair of nearly spherical surfaces of revolution project. above the mean water-level. Each of these surfaces encloses a volume equal to that of the earth, and is slightly variable in shape. They move so that their axes, while always passing through the centre of the earth, pass also always through the centres of the sun and moon respectively. The tides due to either of these spheroids may be expressed as a series of constituents, each of which varies harmonically in a period determined by astronomical data. From dynamical principles it follows that to each of these constituents there will correspond a similar constituent in the actual tides, that is, a constituent varying harmonically in the same period. To find, in the actual tides at any station, the amplitude of each of these constituents, together with the lag of its phase behind that of the corresponding constituent of the generating potential, is the object of the harmonic analysis of tidal observations. Let us consider the speeds of the constituents of lunar origin; we have to examine the motion, relative to any point on the earth’s surface, of the spheroid whose axis passes always through the moon. The pole of this spheroid which is nearer the moon is a little further from the earth’s centre than is the opposite pole, while the whole departure from sphericity depends on the distance of the moon. Let y denote the angular speed of the earth’s rotation and o the mean motion of the moon, If the moon moved with constant angular speed in the plane of the equator and at a constant distance from the earth, we should have, at any station, high water occurring regularly at intervals of «/(y — oc), with a maximum range of tide at the equator. The rise and fall of the water would not quite be simply harmonic, hut could be resolved, with sufficient accuracy, into a harmonic constituent of speed 27 — ¢), of amplitude inversely proportional to the cube of the moon’s distance, and two much smaller constituents uf speeds ¥-% 3-2) and of amplitudes inversely proportional to the fourth power of the moon’s distance. The fact that the moon does not move as here supposed causes many modifications, but it is only on the constituent of speed 2(y—o) that their effect need be considered. ; Let us still suppose the moon to move in the equator, but take into account the * Brit. Assoc. Report for 1918, pp. 15, 16. . Prwde ON HARMONIC ANALYSIS OF TIDAL OBSERVATIONS. 825 elliptic, evectional and variational inequalities in her distance and motion, These inequalities have speeds 7— «a, 2(0 — w), o¢—2n+ @, 2(0 — n), where w denotes the mean motion of the lunar perigee and 7 that of the sun. The effect of each is to make the moon’s sidereal motion increase and decrease with the reciprocal of her distance, and thus to make the period of the tides increase and decrease with their range. The effect of the first order elliptic inequality and the evectional inequality is the introduction of new harmonic constituents of speeds 24y-—97) + (o—-), 2y— oc) + (© —2n + w) of which, for the reason just given, the greater are those of speeds 2(y-—9) —(o-w), Wy - 9) —(o — 2n + @). The effect of the second order elliptic and variational inequalities is sufficiently represented by the introduction of new harmonic constituents of speeds {y—9)-Ao-—w), 2Ay--a)— 20 —7). The daily mean level of the water depends slightly on the departure from spheri- city of the spheroid, so that we have long-period elliptic, evectional, and variational constituents of speeds, o—@, o—2n+2, 2(o — n), respectively. 3. If the moon moved with constant angular speed in a parallel of latitude other than the equator, consecutive high tides would be unequal except at the equator, and we should require the introduction of a new constituent of speed Y="; with an amplitude vanishing at the equator. Also, the amplitude of the constituent of speed 2(7—«) would be less than when the moon was in the equator. But since the declination of the moon changes, the diurnal constituent requires modification. If its ampiitude could be regarded as changing harmonically with speed o, it would be replaced by two harmonic constituents of equal amplitudes and speeds y-cuo. Owing to the fact that this is not quite so, the amplitude of the constituent of speed y — 2c is a little greater than that of speed y, and there is another smaller constituent of speed ¥ + 20. Again, introducing the first order elliptic inequality we get new harmonic con- stituents of speeds (y—20)+(¢-w), yt (o—w), of which those of speeds y-ciwW are regarded as forming a single constituent of speed on and slowly varying amplitude. The second order elliptic, the evectional and varia- tional inequalities give rise to new constituents of speeds (y — 2c) —2(¢ — a), (vy — 20) — (o — 2 + w), (y — 20) — 2(¢ — 9). _ Also, the changing declination of the moon causes the amplitudes of the semi- diurnal constituents to vary, but it is sufficiently accurate to take mean values in all cases except that of speed 2(y—). As the effect is to make the speed and range of tide increase or decrease together, we get a new constituent of speed 2(y — o) + 20. 326 REPORTS ON THE STATE OF SCIENCE.—1920. Again, the changing declination of the moon introduces the principal variation in daily mean level, in the form of a constituent of speed 20, which with the first order elliptic inequality gives two more of speeds 20 + (o — w). The amplitudes of all the constituents depending on the inclination of the moon's orbit to the equator vary with the position of the node on the ecliptic. As the monthly mean level also depends on the inclination of the moon’s orbit to the equator, we have a small constituent with a speed N equal to that of revolution of the moon’s nodes. The speeds of the constituents of solar origin may be similarly determined, but only the declinational and first order elliptic effects on the primary constituent need be considered. 4. On collecting the results we have the following tables. The constituents of the same species have similar geographical distributions of generating potential ; they are arranged in decreasing order of magnitude. The symbols are the same as those in general use, with the exception of 0, which is now introduced for the first time. The corresponding amplitude in the generating potential is larger than that of some constituents given in the other species. All the constituents given in the tables have, according to Darwin, larger amplitudes in the generating potential than any omitted. Semi-diurnal Species. Symbol Name Speed M, 5 4 Principal lunar . = . ‘ : 2(y- 0) 8, : - Principal solar . ; é g J 2(7-— 7) N, : 3 Larger lunar elliptic ; : . 24y-30+0 K, - : Luni-solar . : : : : 27 Vy : : Larger lunar evectional ‘ ; } 2y —30 + 2n-—aw L, Smaller lunar elliptic ; : - 24y-c0-a Te : . Solar elliptic . ; : 2y — 38n 2Np mie ; Second order lunar elliptic : : 2y-—4o0 +20 My Lunar variational . ; ; 2y — 40 + 2n A Smaller lunar evectional . : : 2y-—c0-I@Qn +a Principal Diurnal Species. Symbol Name Speed K, b : Luni-solar . Y O, . . Larger lunar 7 — 20 P, $ : Larger solar. 5 — 2n Q, c : Lunar elliptic ; : : y-3c°+0 1 5 : Supplementary lunar elliptic 1 5 yto-—@ OXOH ae ; Second order lunar . - : ¥ + 20 P; . 5 Lunar evectional y—30+2n-—w 22, ~~. 4 Second order lunar elliptic y -4¢ + 2a o; Z ‘ Lunar variational : y — 40 + 2n Long Period Species. Symbol Name Speed Mf ; ; Lunar fortnightly . ; ; : 20 Mm. : Lunar monthly : f é . c-@ Ssa f : Solar semi-annual . . : : 2n — , A Nineteen yearly ; d : A N — : : Ter-mensual . 3 - 2 30 —w — - , Monthly evectional . is C o-—Wn+w MSf . : Fortnightly variational . : c 2(¢ — n) Sa X 5 Solar annual . : 3 : 5 n ees ON HARMONIC ANALYSIS OF TIDAL OBSERVATIONS, 327 Besides the above there is the constituent M, of speed y — o which consists partly of that of variable amplitude of the principal diurnal species and partly of that of amplitude inversely proportional to the fourth power of the moon’s distance. There is also the ter-diurnal constituent M, of speed 3(y — o) and amplitude inversely proportional to the fourth power of the moon’s distance. Shallow Water Constituents. In shallow water a harmonic constituent is accompanied by others having for their phases multiples of the phase of the primary constituent. Also, two harmonic constituents are accompanied by two others, having for their phases the sum and difference of the phases of the primary constituents. Some of these shallow water constituents have speeds the same as those of certain primary constituents. In the following tables only those shallow water constituents are mentioned which it has been the custom to consider hitherto. Primary Constituents affected by Shallow Water Constituents. Primary Constituents of Symbol Shallow Water Effect Speed M, K,, O y+y7— 20 2 N,, M, d(y — ¢) — (2y — 30 + w) Mo, 2MS8,, Ss, M, 4(y — ¢) — 2(y — n) K, M, O, 2(y — ¢) — (y — 20) 0, M, K, 2G 6) ay P, K, 8, 2y — 1) -- 7 Q K, N, (2y — 30 + w)— Mf K,, 0, y —(y — 2c) Mm M,, N, Wy — co) — (27 — 30 + Ww) MSf M,, 8, 2(y — n) — Ay — 0) M, Oo Ne (2y -— 30 + w)— (y — 20) Other Shallow Water Constituents. Primary Constituents of Symbol Shallow Water Effect Speed M, M, 4(y — oc) Mw M, 6(y — «) M, M, 8(v — «) S, 8, aCe) S, s, 6(y — 2) MS, M,, S, 4y — 20 — 2n MK, Me Ks M, O, 37 — 20 2MK, Mee Ons M, XK, By — 40 SK, 8, K, By — 2n MN, M,, N, 4y —bo +o 28M, 8, M, 2y + 20—4n Meteorological Constituents. The observed values of Ssa and Sa are largely of meteorological origin, as also those of S, of speed y — 7. Results of Analysis. 5. In order to show how far the results of harmonic analysis of hourly heights represent harmonic constants we give some figures relating to ten different analyses for Bombay. The tidal observatory chosen is regarded as one of the most satisfac- tory, and the results of the analyses of the records taken there are about the most consistent from year to year. Hach entry in the tables refers to ten different determinations of what ought to be the same constant; by ‘standard deviation’ is meant the square root of the mean of the squares of the differences from the mean. It will be noticed that apart from M, 8, N, K, K, O, P, 328 REPORTS ON THE STATE OF SCIENCE. — 1920. the deviations from year to year are so great as to prohibit any reliance being placed on the results of the customary analysing processes applied to a single year’s record. In fact, instead of the results from all analyses for the same constant being equal, the apparent amplitude for one year is sometimes more than ten times that for another year, while the apparent lags are sometimes distributed through more than three quadrants. We also give some figures relating to three different analyses of tidal currents at Smith’s Knoll (Lightship off Norfolk). In 1911 six weeks’ observations were analysed, but in 1912 and 1913 only two weeks’ observations were analysed. Tidal Heights at Bombay (Apollo Bandar) 1906-1915. wd Clare | Greatest Least ; Mean ptanvand Maximum Standard rae Ampli- Ampli- |Difference) Ampli- | 5, Ampli- Difference| Deviation tude tude tude eiades in Lags | in Lags Feet Feet Feet Feet Feet Degrees | Degrees Me 4-017 3°934 “083 3°970 “021 1-51 “49 Sp 1-569 1-548 021 1:560 007 2°94 “78 No 1-011 "943 “068 -976 023 4-67 1:69 Kg “448 “374 “074 “404 “019 9-60 2°98 V2 *318 033 +285 -200 093 134:55 56°3 Ly “139 “019 120 “079 033 197-09 — T. “240 -022 "218 “151 “066 93°28 29-2 2Ne "213 “056 “157 136 “049 43°33 12°50 Pe 257 ‘177 -080 -208 026 22°87 7°68 Ay —- — — — os —_ — Ky 1:394 1:376 “018 1:386 “006 1:19 34 O; 664 “643 021 *653 007 1:31 “40 Py “431 “403 028 *412 -008 3°07 1:00 Qi 174 “125 049 “154 “014 18-98 5-77 J 148 “052 “096 "096 ‘031 48°13 14-45 00, — -— — — —- —_ — Ps =f = = Dre giv _ — 2Q1 te Sea 2 eS — — a; —_— = —_ ae — | = — Mf 057 O11 046 032 013 91-71 25°2 Mm 127 ‘010 117 058 030 237-91 — Ssa 196 "106 090 142 024 69°94 20°71 Sa 163 "024 139 109 043 252-71 — MSf 075 “014 061 032 019 287-58 _— M, — — — | — — — — M, == se Ss <7 — 455 | 70'8| SO'S| 78°S|| 4, 4-1 | ,,. 7:4] ,, 10°4 1258 |249 |257 30 92D 95 | 145,15, 5 >, || 65°6| 80°7| 73°3 | 3» D3 |5,9°7 |,, 9°$1|260 |248 258 The negative sign prefixed to the minimum current indicates that the current turns in the clockwise direction. Harmonic Analysis of Hourly Heights. 6. We assume that the height of the water at any station may be expressed as the sum of a number of Fourier’s series in time. In each of these series only a few terms are important; for instance, in the largest (M) series, the important terms are the constituents M,, M,, Mg, M,, M,, M,, while in others (e.g. N or O) there is only one important term (N, or O,). A typical short period series will have speeds O,, 26,, 30, A B where o;, is that of the diurnal constituent. We shall take r = 0 for the principal solar series, so that 27/0) is a mean solar day. The data for analysis consist in a number of heights at intervals of time equal to one mean solar hour. Noy, » The Isolation of the Principal Solar Series. Arithmetic means are taken of the heights at the times h 2a h\ 2r h\ 2n h\ 29 — 1+ —) =, (2+ —)— Nie dot Sie bie. e. ( +34) a,’ ( + 7) ee sah +) ne @) for each of the values0,1,.2, . . - - 230fh. For any value of h this process will leave unchanged the term Ros (mot —«) . : : - : : (2) and consequently the whole § series. From the term R cos (mo,t —) . : : : 5 : (3) however, it will give * > cos fan(« + AL nl, @ weds binosde aff) which is equal to a B cos an] » (=~ 1)+ i ale-¢. Phe opaili oF 1O1Qgy 830 REPORTS ON THE STATE OF SCIENCE.—1920. and to 1 sin{Nn(o,/o, — 1)t} p 3 A te ya 7h be eater N_ sin{n(o,/c, — 1)r} doa. dus o, Y) + Satetlnnle (6) on summation. If o,/o, is sufficiently near to unity, (6) may be replaced by sin{Nn(o,/o, — 1)7} N—-1/or _ hoy| _. Na(o,/c, — 1) ee {onl 2 (« 1) +94 | } ae? which is exactly what we should have obtained if we had replaced (5) by the integral 0 I Cy (Sens = we feos 1) +f 2 lr — elas Hep se the NS) It is the general practice to choose N so as to make as small as possible the residue (6) from some one large term of the type (3). When a year’s record is to be analysed the value of N chosen is 369, and it is then generally assumed that all the residues (6) may be neglected; in other words, that the isolation of the S series is complete. With a month’s record Darwin’s plan is to use for N both 30 and 27, and with a fortnight’s record both 15 and 14. It is assumed that the amplitudes of K, and P, bear to those of 8, and K, respectively the equilibrium ratios, and that the lags of K, and P, are equal respectively to those of 8, and K,, while T, is supposed simply proportional to 8,. The residues from all other constituents are neglected. For N = 369 and the constituents M,, Noy K,, K,, O,, E the coefficient - 1 sin { Nx(a;] 09 = 1)r } : ‘ y (9) N sin { 2(0,/0) — 1)r } ; . in (6) takes the values 000, -008, -010, ‘010, ‘000, 010 respectively, and the corresponding coefficient in (7) takes the same values. For N = 15 and the constituents M, N,, K, (9) takes the values 7016, -204, 989, respectively, and the only effect of replacing (6) by (7) is to give ‘200 instead of “204. For N = 14 and the constituents K,, O,, P,, (9) takes the values 998, -014, -998 respectively, which are not affected by replacing (6) by (7). The Isolation of the other Series. 7. We shall now consider the isolation of the series which has o for the speed of its diurnal constituent, and shall refer to 2m/o as a ‘special day.’ For the isolation to be carried out exactly like that of the S series we should require the heights at intervals of time equal to a ‘special hour.’ The method of summation we should then have is made the basis of the actual methods now under considera- tion. With each place in the summations is associated a definite time, and this in general is necessarily different from that of the height which is assigned to the lace. : There are two ways in general practice of making the assignment, and we shall refer to these as the B.A. and the Abacus assignments. The first is used by Roberts and the Survey of India, while the second is that of Darwin’s tidal abacus. igh ON HARMONIC ANALYSIS OF TIDAL OBSERVATIONS. 881 In the B.A. assignment all the given heights are used and the maximum difference between the time of a place in the summations and that of the height assigned to it is 7/240 or half a special hour. When the times of two of the given heights are nearer to that of a place than this interval, both are assigned to it, while when no height has a time as near as this interval, none is assigned to the place. The former case occurs regularly when o <4, the latter when o>a,. In both cases the mean is formed by dividing by the total number of heights used in the summation. In Darwin’s tidal abacus the height at each mean solar noon is assigned to that place in the summation whose time differs from this noon by less than half a special hour, while any two consecutive heights belonging to the same mean solar day are assigned to consecutive places in the summation. As in the B.A. assignment all the given heights are used so that two heights are assigned to certain single places when o oy. Let us now examine the effects of these averaging processes on the various constituents. Taking firstly the term R cos (mat — €), A : : : f (10) the summation for the special hour / will give N-1 = 20 (3 + MoT, — ‘) B . : (11) = where 7, denotes the excess of the time of the (s + 1)th height in the summation over that of the place to which it is assigned, and N the number of terms in the summation. Now, for given values of o, m, and N, the sums 1 N-1 : - N-1 N > cos (mors), XN > sin (mors) é - (12) s=0 3s=0 may be determined accurately by direct addition. This would be laborious and the sums are replaced by integrals. For the B.A. assignment they are replaced by T T = | cos (mor)dr, mn sin(mort)dt, . 4 . (13) —T —T respectively, where T is half a special hour. The effect is to replace (11) by sin moT mhar sin mer B cos (Tanas) ce Bae eS For the abacus assignment (11) is replaced by sin mm/24 sin { m(a]o9 — 1)r} m 7 mm|24 Ree 1)r R cos { “I 3 (a = “4 + a] m—€ S . (15) Taking next the term Ricos. (not6)scucuin GBlo (rte tashe an ee the summation for the special hour h will give N-1 : = >> cos no;| (8+ 3a) o* |-¢. fet: Ges) which we shall refer to as the residue from (16). Again, for given values of o, o;, m and N, the series N-1 N-1 x Bomar (2 +n) E Bin | ne 2 a “I, . (18) s=0 832 REPORTS ON THE STATE OF SOIENCE.—1920. may be calculated accurately by direct addition, and although this would be very laborious it could be done once for all. Again, it is the general practice to try to choose N so as to make as small as possible the residue due to some one large constituent, and then to neglect all the residues. For example, when a year’s record is available the B.A. plan is to take N = 357 for the M series and N = 343 for the O series. Darwin's plan for a month’s record is to replace these numbers by 29 and 25 respectively, and for a fortnight’s record by 14 and 13 respectively. These values are taken on the basis of the formula (17) with 7, omitted. Analysis of the Separate Series. 8. From the isolation process for each series we have 24 values G ’ Gq ? - - . Gus Hl 2 ~ os associated with times which differ by intervals of one special hour. Certain fractions of these values are residues from other series. The usual method of analysing the Fourier’s series into its separate terms is by what we may call the ‘least square rule.’ If the series is expressed by (= A, + BR, cos (ot — €,) + R, cos (Qot—€,) . . + Rm cos (mat —€m) . (19) the rule is given by Ay = 24 ee Gu. h=0 Fe y/ le mir Rin COS Em = ia > G, cos iy : : ° (20) h=0 1 ee y/ : 5 = mh Rn sin Em = B= qG sin i= and its application to the cases in question would be quite accurate if the isolation were perfect. We must therefore consider the effect on the results of imperfect isolation. Taking the § series, the effect of a term of the type h 2no,30 R — Le : 5 5 cos 8 tated .) - ‘ (21) on A, is 1 sin (no;/a)) Rp 23 now fi an GaP, Go nee, a ce so that the effect of the term (3) on A, is 1_ sin (Nno;t/%) pp’ 23)\ no, 24N sin (no,1/240,) ae { a El se) ae ¢}. ae The effect of (21) on Ry» cos €m is Rf sin{(no,/oo + m)r} (23 (ney sal anlenectos + m)n]24} °°S fia + m)\r = ¢ ei CLE Teme? cos te, — m)s - |]. : (24) + sin{(no;|/o) — m)n/24} When 2 = m and a;/ao is near unity the second part of this is much larger than the first, and it reduces to 23 Or R cos {5am (% -1)*-«} (25) ON HARMONIC ANALYSIS OF TIDAL OBSERVATIONS. 8338 approximately ; similarly the effect of (21) on R,, sine, reduces to . {23 o - Rsin {54m (-1)*-«} (26) approximately. On combining (7) with (25) and (26) we obtain as the corrections to R,», cos €, and Ry», sin €, required by (3) — FReos(k—e), F Rsin (« — 6), (27) respectively, where ~1)9 : ge «= n(n ~ 54) (2 1) (28) If these corrections are small compared with R,», they give 5 Rn = — F Roos (k + €» — ©), . 5 en = F Rsin (« + €m — ©); } i) which we notice involve only the relative phase em — «. Darwin's Method for Solar Constituents. 9. This method consists in applying the S series isolation process and the least square rule to different sets of 30 consecutive days’ record and then analysing the resulting sets of values for yearly and half-yearly harmonic variations. When a year’s record is available, 12 sets of 30 days are used, and from the results values of ars eas) este ny SEs) Sate ANON ee \oeet oe are immediately taken. Residues from M, are allowed for. When less than a year’s but as much as half a year’s record is available, Ssa is neglected. Analysis of Hourly Heights for Long Period Constituents. 10. There are two methods in general use, and we shall refer to them as the B.A. method and Darwin’s short method. The B.A. method is used by the Survey of India. The principle of the B.A. method is the least square rule applied to daily mean heights, using one decimal place for the multiplying sines and cosines, The residues from all primary astronomical constituents are allowed for. Darwin’s short method uses the principle of isolation and proceeds on a plan similar to the assignments, the daily means taking the place of the given hourly heights. Residues from M, are allowed for, but no great accuracy is claimed for the method ; Darwin gave it as a much Jess laborious process than the B.A, method. Darwin's Method for Harmonic Analysis of High and Low Water Observations. 11. If ¢ denote the height of the water at time ¢, it will be given by an equation of the type ¢ = R, cos (o,t—€,) + = R, cos (a;t—«,), : : . (80) r where o, is no longer the speed of S,, but that of any constituent conveniently chosen to play a special part in the analysis. At the time of high or low water we have 0 = R, sin (o,¢ — ¢,) + DR, mune €or. CL) 0 and if we let : ieiabberdc! ovis: cure Seater oe ET Wena 834 REPORTS ON THE STATE OF SCIENCE. —1920. denote respectively the times and heights of consecutive high and low tides, we deduce from (30) and (31) N a S (s COS Outs — R, COS €y s=1 N 1 1 oy es = NS > By [a(i+ = ) cos (a; —o5)ts cs} ry s=l1 C,. ( +4 ( - =) cos port Oy)ts — €r | a) . (83) N 2 Dd G sin ots — Ry sin € s=1 N ake >» | 4 (: + 3) sin Ca «} r s=1 -3 ( 1 n) sin { (Gr | Oy)ts — € | % 1, . cos | (0) -- oy)ts — € sf Dseoot eteoe a aod MSE) N s=1 If in the terms we may approximate by substituting t=tt+(-1)%, Se eee ae cos {(« = *) (« gil = ir) — or} STSGe. OCG) This vanishes when N is an exact multiple of 20/(¢,—o,), or when the tides taken cover an exact number of synodic periods of the constituents of speeds o, and a;,, while if N has the value of o/(c, — o,), or the tides taken cover exactly half a synodic period of the constituents of speeds ¢, and o,, and (o; — 9,)/¢ be small, (36) is equal to 2 N --1 x 008 {Cer — 9) (« CT *) = cf : : 7 (37) approximately. These are the equations and relations on which the method is based. When analysing for M,, R, cos (o,¢ — ¢,) is taken as this constituent, and N is chosen so that the tides considered cover an exact number of semi-lunations. ° It is then assumed that the summations on the right of (33) may be neglected, so that we get N R, cos € = = D ( cos apts, s=1 P - - : (38) Ry sin €, = S ¢ sin agts, e=1 > When analysing for N, and L,, R, cos (ot — €,) is again taken as M,, but N is chosen so that the tides considered exactly cover a semi-lunar-anomalistic period. Two series of 13 such sets of tides are taken, the tides in each series being mals ON HARMONIC ANALYSIS OF TIDAL OBSERVATIONS. 335 consecutive, and one series beginning a quarter-lunar-anomalistic period after the other. By subtracting the equations (33) for consecutive sets in each series, M, is eliminated from each series, and the results are then combined so as to eliminate first N, and then L,. In these final equations it is assumed that all other constituents may be neglected, and even for N, and L, that the terms involving (1 — a,/o,) may be neglected, while those of the type (86) may be replaced by terms of the type (37). To find §8,, R, cos («,¢ — «,) is taken as S, and N is chosen so that the tides considered cover an exact number of semi-lunations, All constituents except K, and T, are then neglected in the summations. It is assumed that the amplitude of K, bears to that of S, the equilibrium ratio, and that their lags are equal, while T, is supposed simply proportional to §,, In the summations involving K,, the terms containing (1 — o,/c,) are neglected. To find K,, R, cos (o,¢ — ¢,) is again taken as §, and two sets of the same number of tides are taken so that one begins 3 months after the other. Again T, is taken proportional to §,, the factor of proportionality changing a little from one set to the other. By subtracting corresponding equations (33) for the two sets, the terms involving 8, become small, and when the value of §, already found is used, we have two equations for the amplitude and lag of K,. All other constituents are again neglected in the summations. In finding K, and 0, the procedure is analogous to that for finding N, and L,, M, taking the place of M, and a semi-lunar period taking the place of a semi-lunar anomalistic period. This time, however, the contributions of M, and §, to the summations are accurately computed with the values of these constituents already found, while K, and P, are supposed to have their amplitudes in the equilibrium ratio and their lags equal. The finding of P, is analogous to that of K,, the process for K, and O, taking the place of that for §,. Only the constituents M,, S,, N., K,, L, and K,, O,, P, are considered. Correlation with Generating Potential. 12. The amplitudes of some of the harmonic constituents of the generating potential are really variable, though the variations are very slow. Also, some of their speeds have not quite the values scheduled, though again the deviations are small. In both cases the effects take a long time to accumulate and the changes may be neglected over a year, while a longer record is not subjected to a single analysing process. When the amplitude and phase of a constituent observed at any particular time are connected with the generating potential, the deviations mentioned have to be taken into account. There is one type of case, however, in which this does not appear to have been adequately done. It is the case in which shallow water constituents have speeds equal to those of constituents of other origin. When the ratio of the amplitudes and the difference of the phases of two constituents are slowly changing, it is clear that true tidal coustants cannot be obtained until the constituents have been separated in some way. Such separation has never been made, and this fact may possibly account for some of the irregularities in the results from year to year, especially for some of the long period constituents.* Historical Account. 13. In 1866 Prof. Thomson (afterwards Sir William Thomson and Lord Kelvin) applied to the Admiralty for a year’s record of any trustworthy tide-gauge, and received that of Ramsgate for 1864. This he began to analyse harmonically with the aid of Messrs. E. Maclean, J. Smith and W. Ross of the University of Glasgow, at first using three-hourly heights but afterwards hourly heights. Approximate values for M, and 8, were found and the existence of Ssa and Sa detected. * In the preliminary report it was stated that the inconsistencies in the results _ for long period constituents are not due to defects in the method of analysis. This _ Was based on the fact that residues are allowed for; the subject of the present section was not there considered. 336 REPORTS ON THE STATE OF SCIENCE.—1920. At the Meeting of the British Association in 1867 Thomson obtained the appoint- ment of a committee which, during the following nine years, carried out harmonic analyses. The grants from the Association to the Committee amounted to £1,000, and the work was done, under the superintendence of Thomson, by Mr. KE. Roberts, of the Nautical Almanac Office, and assistant computers working under his imme- diate direction. To the members of this committee, in December 1867, Thomson issued a circular, containing, among other things, the speeds of the constituents M, K, Mf M, 8, 8, 0, Mm M, N, P, Ssa K, Q, Sa L, J, T, ‘y — 3m’ R iS) We have explained the nature of all these except R, and ‘y — 3n,’ which are solar constituents analogous respectively to the lunar constituents L, and Q,. In the development of the generating potential their amplitudes are less than those of constituents which have always been neglected. Thomson gave S, as an astronomical constituent analogous to M,, and the speed of Mm asco instead of o — w, as was afterwards pointed out by Roberts. He thought that while all the above constituents would be sensible on our shores, the effects of evection and variation would be negligible. He also stated the ‘ equilibrium principle’ of allowing for the changing inclination of the moon’s orbit to the earth’s equator. From the Ramsgate 1864 record the terms of the M, K, 8, O, N, L series were first found. Special hourly means for the year were formed using the B.A. assignment, and then analysed by the least square rule using the tabular forms given by Archibald Smith for the deviation of the ship’s compass. This analysis revealed the shallow water constituents My, M,, M,, Sy and this then suggested the possible presence of MS, and MSf. By means of these first approximations a complete calculation of residues was made, but it was afterwards concluded that first-approximations were sufficient for short-period constituents, and no other residues for such constituents were calculated by the Committee. From the same record numbers for Mf, Mn, Ssa, Sa, MSf, were found, by using daily means for the year purified of lunar short-period influence before analysis. As a test, an hourly tide-table for one day in 1864 was made and compared with the original record. The errors reached a foot at half-tide (mean spring amplitude =8 ft.). A series of records taker at Liverpool were supplied by the Board of the Mersey Dock Estates, and from that for 1857-8, values for the M, K, 8S, O, N, L series were found. A set of personal observations taken at Bombay were supplied by Mr. W. Parkes, a member of the Committee, and special quarter-hourly means for 127 days were formed and analysed for the M, K, §, O, N, L series. 14. From the Liverpool 1857-8 record the constituent P, was found, and then the 1858-9 and 1859-60 records were analysed similarly. The constituents T, and R, were also treated, each from two two-yearly records. Now that records taken in different years at the same station were considered, correlation with the generating potential was made, and a Liverpool hourly tide ON HARMONIC ANALYSIS OF TIDAL OBSERVATIONS. 337 table for 13 specially chosen days in 1869 was constructed and compared with the corresponding record, To examine the variation of certain constituents with the inclination of the moon’s orbit, the record for 1866-7 was analysed. It was decided that the variation was not quite according to the equilibrium principle, but was afterwards always treated as if it were so. The new results of analysis were incorporated in the tide-table and then the determination of y,, w, and A, was suggested and carried out for each of the four years taken. The tide-table was again emended and compared with the record: the discrepancies over two typical days are shown in Fig. I. The determination of MS, was suggested and the analysing process applied to each of the four yearly records. The tide-table was emended accordingly and the results again compared with the record. The final discrepancies over the two typical days are shown in 3 FEET + rx) Figs. I. AND II. —Difference between Predictions and Record for Liverpool, April 26 and 27, 1869. Fig. II. It should be stated that the tide-table contained a number of constituents of amplitudes less than 0°1 ft. Numbers for Mf, Mm, Ssa, Sa, Msf were also obtained from each of the four yearly records, but were inconsistent from year to year. The Ramsgate 1864 record was next further analysed for Dior ep PAM MSy A set of quarter-hourly observations taken during several periods within four days in the Fiji Islands, and supplied by Lieut. Hope, R.N., were partially analysed. The difficulties presented by the shortness of the periods led Thomson to apply to the U.S. Coast and Geodetic Survey for a trustworthy record of Pacific tides. He received that of Fort Point, California, for 1858-9, and it was analysed for all the constituents considered at Ramsgate. As a test an hourly tide-table for 14 days was made without p,, A,, the long-period constituents and MS,, but including several 1920 Z 338 REPORTS ON THE STATE OF SCIENCE.— 1920. constituents of amplitudes less than 0:1ft. The discrepancies over two typical days are shown in Fig. III. A Karachi record for 1868-71 was supplied by Mr. Parkes and analysed for all the constituents considered at Liverpool, together with Q, J). An hourly tide-table for 29 days in 1868 was made without T,, Q,, J,, the long-period constituents and M§,, but including several constituents of amplitudes less than 0:1 ft. The discrepancies over two typical days are shown in Fig. IV. Fia. IlI.—Difference between Predictions and Record for Fort Point, March 16 and 17, 1859. Fie. [1V.—Difference between Predictions and Record for Karachi, November 11 and 12, 1868. Next, three further yearly records of Liverpool tides were analysed for the same constituents as before, with the exception of those of long period. Also, two further yearly records from Fort Point were analysed, the constituents Q, and J, being added. A thirteen months’ record from Cat Island, in the Gulf of Mexico, was obtained from the U.S. Survey, and analysed for the M, K, 8, 0, N, L, P, Q J series, as well as the long-period constituents. From the Ramsgate 1864 record the constituents 28M, and 3MS5, were found, the latter being a shallow-water constituent of speed 4y — 60 + 2n, derived from S, and M,. Another yearly record from Karachi was analysed for all the constituents yet considered. Four yearly records from Portland were analysed for the same constituents as at Ramsgate, with the exception of those of long period. In the British Association Report for 1872, Roberts gave a harmonic development of the semi-diurnal tide generating potential. 15. In 1874 Lieut. (afterwards Col.) A. W. Baird, of the Survey of India, set up tidal observatories at Hanstal, Navanar, and Okha Point. He was afterwards deputed to Europe to study the practical details of tidal registration and harmonic analysis. With the help of Roberts in England, he analysed the records from the observatories he had set up. The British Association Committee further analysed records for Hilbre Island, eine ON HARMONIC ANALYSIS OF TIDAL OBSERVATIONS. 339 Karachi, San Diego and Fort Clinch. When its funds were exhausted Thomson tried to obtain £150 from the Government but was unsuccessful. The amount was provided by the Royal Society out of their Government Grant Fund, and with it records from West Hartlepool, Port Leopold, Beechy Island, Brest and Toulon were analysed. For the 1876 British Association Meeting Thomson drew up a final report and gave an investigation into the generating potential, tabulating speeds, arguments and amplitudes. A record taken at Freemantle by the Admiralty provided the first case of harmonic analysis for a station in the Southern Hemisphere. Under the influence of Thomson the Hydrographic Office was searched for other Southern Hemisphere records, but the only ones found were from Port Louis, Mauritius and Port Louis, Berkely Sound. Harmonic constants from these as well as from records taken at Toulon, Marseilles, and Malta, were published by Thomson and Capt. Evans, R.N. On Buird’s return to India in 1877 the systematic observation and analysis of tides was there begun, he training the original staff of observers and computers. Thomson next constructed the first mechanical harmonic analyser with the aid of grants from the British Association and the Royal Society. It was designed to determine the constituents M, 8, K, O, M, but has never been used for this purpose. It is deposited in the Museum at South Kensington. At the 1882 British Association Meeting Prof. Darwin (afterwards Sir George Darwin) communicated a paper in which he pointed out that the methods of analysis which had been used for the long-period constituents might be seriously in error. A committee consisting of Profs. Darwin and Adams was appointed to examine the whole subject of harmonic analysis. In 1883 and 1885 Darwin presented reports which have ever since formed the standard manual on the subject. They contain an elaborate analysis of the generating potential (several errors in the report of 1876 being indicated) and a complete treatment of the methods of analysing hourly heights. These methods, except for T., R, and the long-period constituents, do not differ essentialiy from those which had been used by Thomson’s Committee ; they complete the evolution of what we have called the B.A. methods. In 1885 Baird and Darwin published an up-to-date collection of results of analysis; the number of stations considered was 43. 16. In 1885-6 the Canadian Expedition to Hudson Bay under Lieut. Gordon, R.N., was made and short series of observations taken at five stations in Hudson Straits were afterwards harmonically analysed by Gordon with the aid of Prof, Carpmael of Toronto. In a final report (1886) of the British Association Committee Darwin gave his methods of analysing short records. In 1886 Baird left the Tidal Department of the Survey of India and published his ‘ Manual of Tidal Observations.’ The methods of observation and analysis which he had established have been continued without modification up to the present time; they consist precisely of the B.A. methods, Baird constructing auxiliary tables. In 1889 Darwin published a second up-to-date collection of results from all ‘sources, showing an increase of 27 stations since 1885. Tn 1890 Darwin gave his method of harmonically analysing observations of high and low water, and in 1892 his new method for solar constituents and his short method for long-period constituents. In the same year he published his design of the ‘tidal abacus,’ an apparatus for facilitating the computations in the analysis of ‘hourly heights. This apparatus has since been much vsed. In 1891 the Australasian Association appointed a committee to report on the tides of South Australia. Two of the members of this committee, Prof. R. W. Chapman and Capt. A. Inglis, afterwards analysed records from Port Adelaide and Port Darwin. In 1894 the Survey of Tides and Currents in Canadian Waters was instituted by the Canadian Government, and this organisation has worked continuously up to the present time under the direction of Dr. W. Bell Dawson. The harmonic analyses have keen made for the Survey by Messrs. Roberts, a firm of computers founded by Mr. E. Roberts of Thomson’s British Association Committee, but only a few of the tesults have been published. z2 340 REPORTS ON THE STATE OF SCIENCE.—1920, Mr. T. Wright, of the Nautical Almanac Office, has analysed records by Darwin’s methods with aid from the Royal Society Government Grant Fund. Darwin and Messrs. Selby and Hunter have analysed with the abacus records for Antarctic expeditions, and Selby has similarly analysed records for the National Physical Laboratory. Roberts has made new analyses for Liverpool and Dover, the former for a British Association Committee, the latter with the aid of a small grant from the Royal Society Fund. In New Zealand tidal work began in 1909 and has been entirely under the charge of Mr. C. E. Adams, the Government Astronomer. Records have been analysed by the use of Darwin’s abacus and computation forms, and the results checked by Mader’s mechanical analyser. This appears to be the only use that has been made of mechanical analysers, in spite of the number of different machines that have been invented. In Western Australia records have been taken and analysed by the Government, under the direction of Messrs. Cooke and Curlewis, Government Astronomers. Prof. D’Arcy Thompson has studied averages of consecutive high and low waters at Aberdeen, Dundee and Milford Haven, giving values for Ssa and Sa at these Stations. He has also published lists of Ssa and Sa constants obtained from various sources. The Admiralty has announced that for the North Sea the customary methods of harmonic analysis lead to predictions which are entirely in error. In 1911 the British Government, in connection with the ‘Conseil Permanent International Pour l’Exploration de la Mer,’ began the taking and harmonic analysis of continuous observations of tidal currents in the North Sea. British Work on Harmonic Analysis of Tidal Heights. BIBLIOGRAPHY. 1868.* Sir W. THomson, Report of ‘Committee for the purpose of promoting the extension, improvement, and harmonic analysis of tidal observations.’ Brit. Assoc. Report, pp. 489-505. [Thomson’s Circular is reprinted in Pop. Lect. and Add., pp. 209-223]. E. RoBERTS, Report supplementary to Thomson’s, Brit. Assoc. Report, pp. 505-510. 1870. Sir W. THomson, Report of same Committee for 1869, Brit, Assoc. Report, pp. 120-123. Sir W. THOMSON, Report of same Committee for 1870, ibid. pp. 123-125 ; 148-151. KE. ROBERTS, ‘ Statement of work performed by him,’ ibid. pp. 125-148. 1871. E. RoBERTS, Report of same Committee, Brit. Assoc. Report, pp. 201-207. 1872. E. RoBeRts, Report of same Committee, Brit. Assoc. Report, pp. 355-395. 1876. Sir W. THomson, Report of same Committee, Brit. Assoc. Report, pp. 275-307. 1878. Capr. EVANS and Sir W. THomsoN, ‘On the Tides of the Southern Hemi- sphere and of the Mediterranean,’ Brit. Assoc. Report, pp. 477-481. [Nature, v. 18, pp. 670-672. ] Sir W. THomMsoN, ‘ Harmonic Analyser,’ Proc. Ray. Soc., v. 27, pp. 371-373. 1881. Sik W. TnHomson, ‘The Tide Gauge, Tidal Harmonic Analyser and Tide Predicter,’ Proc. Inst. Civil Eng1's., v. 65, pp. 2-25. 1882. G. H. Darwin, ‘On the Method of Harmonic Analysis used in deducing the numerical values of the Tides of Long Period... , Brit. Assoc. Report, pp. 319-327. 183. G. H. DARWIN, ‘Report of a Committee for the Harmonic Analysis of Tidal Observations,’ Brit. Assoc. Report, pp. 49-118. [Sci. Papers, v. 1, pp. 1-68. ] 1884. G. H. Darwin, Second Report of same Committee, Brit. Assoe. Report, pp. 33-35. 1885. G. H. Darwin, Third Report of same Committee, Brit. Assoc. Report, pp. 35-60. [ Sei. Papers, v. 1, pp. 70-96. ] A. W. Barrp and G. H. Darwin, ‘Results of the Harmonic Analysis of Tidal Observations,’ Proc. Roy. Soc., v. 39, pp. 135-207. 1886. G. H. DAgwin, ‘Fourth Report of Committee for Harmonic Analysis . . ,’ Brit. Assoc, Report, pp. 41-56. [Sei. Papers, v. 1, pp. 98-116.] *For Brit. Assoc. Reports, the dates are those of the meetings to which the volumes refer ; in other cases the dates are those of publication. ON HARMONIC ANALYSIS OF TIDAL OBSERVATIONS. 341 1886. G. H. DARWIN, ‘Instructions for the Reduction of Hourly Tidal Observations . . . Admiralty Scientific Manual, ‘ Tides.’ [Sci. Papers, v. 1, pp. 122-139. ] 1889. G. H. DARwIn, ‘Second Series of Results of the Harmonic Analysis of Tidal Observations,’ Proc. Roy. Sec., v. 45, pp. 556-611. 1890. G. H. DARWIN, ‘ On the Harmonic Analysis of Tidal Observations of High and Low Water,’ Proc. Roy. Soc., v. 48, pp. 278-340. [Sci. Papers, v. 1, pp. 157-215.] 1892. G. H. DARWIN, ‘On an Apparatus for Facilitating the Reduction of Tidal Observations, Proc. Roy. Soc., v. 52, pp. 345-389. [Sei. Papers, v. 1, pp. 216-257. ] 1902. T. WRIGHT, ‘ Harmonic Tidal Constants for certain Australian and Chinese Ports,’ Proc. Roy. Soc. (A), v. 71, pp. 91-96. 1904, J. N. SHOOLBRED, ‘ The Tidal Régime of the River Mersey,’ Rrit. Assoc. Report. 1906. J. N. SHOOLBRED, ‘The Tidal Régime of the River Mersey . . ,’ Proc. Roy. Soc. (A), v. 78, pp. 161-166. 1907. Siz G. H. DaRwi1y, ‘ On the Antarctic Tidal Observations of the “ Discovery,” ’ Sct. Papers, v. 1, pp. 372-588. [Wat. Antarctic Hxp. 1901-1904, Phys. Obs., . 3-12. 1908" F. J. ee and J. DE G. HUNTER, ‘ Tidal Observations of the ‘‘ Scotia,” 1902- 1904,’ Nat. Antarctic Hxp., 1901-1904, Phys. Obs., pp. 13-14. 1909. T. WricgHt, ‘Harmonic Tidal Constants for certain Chinese and New Zealand Ports,’ Proc. Roy. Soc. (A), v. 83, pp. 127-130. 1910. Sir G. H. DARWIN, ‘The Tidal Observations of the British Antarctic Expedition 1907,’ Proc. Roy. Soc. (A), v. 84, pp. 403-422. 1911. F. J. Sevpy, ‘ Analysis of Tidal Records for Brisbane for the year 1908,’ Proc. Roy. Soc. (A), v. 86, pp. 64-66. 1913. E. ROBERTS, ‘ Re-reduction of Dover Tidal Observations for 1883-4, &c.,’ Proc. Roy. Soc. (A), v. 88, pp. 230-233. 1914. D’ARcy W. THomMpPson, ‘On Mean Sea Level and its Fluctuations,’ Fishery Bd. Scotland, Sci. Invest. iv. British Work on Harmonic Analysis of Tidal Currents. The work has all been done in connection with the ‘ Conseil Permanent Inter- national pour 1l’Exploration de la Mer,’ and the results published in the Bulletin Hydrographique for 1911, 1912, 1913. Harmonic constants are given for the northerly and easterly components of the current and also for the current-ellipses, at various depths at each station. The English observations have been made on steamships and lightships under instructions from the Board of Agriculture and Fisheries. The Scottish observations were taken on board the ‘ Goldseeker’ by the ‘ North Sea Investigation Committee,’ under instructions from Prof. D’Arcy Thompson. Indian Work on Harmonic Analysis of Tidal Heights. The work has all been done by the ‘ Survey of India,’ a Government institution. The results are published in the annual volumes of the ‘ Records of the Survey of India’; prior to 1908 these volumes were called ‘ Extracts from Narrative Reports of the Survey of India.’ Tn 1901, vol. 16 of the ‘Great Trigonometrical Survey of India’ was published, being written by Mr. J. Eccles. It deals exclusively with tidal work and gives full accounts of methods used, work done and results obtained up to 1892. Canadian Work on Harmonic Analysis of Tidal Heights. A few results are published in the annual ‘ Reports of Progress’ of the ‘Survey of Tides and Currents in Canadian Waters.’ Australian Work on Harmonic Analysis of Tidal Heights. BIBLIOGRAPHY. 1892. R. W. CHAPMAN and A. INGLIS, ‘The Tides of the Coast of South Australia, Aust. Assoc. Report, iv., pp. 230-232. 1894. R. W. CHAPMAN and A. IN@uIs, ‘The Tides of Port Adelaide,’ Aust. Assoc. Report, v. 342 REPORTS ON THE STATE OF SCIENCE.—1920. 1898. R. W. CHAPMAN and A. INGLIS, ‘The Tides of South Australia,’ Aust. Assoc. Report, vii., pp. 241-244. 1902. R. W. CHAPMAN and A. IN@LIS, ‘The Tides of Port Darwin,’ Ast. Assoc. Report, ix., pp. 67-68. 1903. R. W. CHAPMAN, ‘ The Tides of Port Darwin,’ Nature, v. 68, p. 295. 1914. H. B. CURLEWIS, ‘The Tides, with special reference to those of Freemantle and Port Hedland,’ Journ. R.S. West Aust., v. 1. 1916, H. B. CuRLEWIS, ‘ Tide Tables for Port Hedland, 1917’ (Perth, W.A.). Work done in New Zealand on Harmonic Analysis of Tidal Heights. This work is done by the Government Department of Lands and Survey. The results are published in the annual ‘ Reports of Survey Operations’ and in papers by C. E. Adams. Papers by C. H. Adams. 1909. ‘The Wellington Tide Gauge,’ Trans. N.Z. Inst., v. 41, pp. 406-410. 1912. ‘ Harmonic Tidal Constants of New Zealand Ports—Wellington and Auckland,’ Aust. Assoc. Report, v. 14. 1913. ‘ Harmonic Tidal Constants of New Zealand Ports—Wellington and Auckland,’ Trans. N.Z. Inst., v. 45, pp. 20-21. 1914. ‘Harmonic Tidal Constants of New Zealand Ports—Dunedin and Port Chalmers,’ 7vans. V.Z. Inst., v. 46, pp. 316-318. British Work on Harmonic Analysis of Tidal Heights. Analyses Made. a Date e : Porte Station Dates of Record Analysed a gi ie for cation < 1868 | Ramsgate 1864 1 | Admiralty. Liverpool 1857-8 2 | Mersey Dock Ba Bombay ... 1867 2 | Parkes. 1870 | Liverpool 1857-8, 1858-9, 1859-60, 1866-7| 92 Mersey Dk. Bd. Ramsgate 1864 2 | Admiralty. Fort Point 1858-9 2 | U.S. Survey. Karachi ... 1868-9, 1869-70 2 | Parkes. H 1871 | Liverpool 1866-7, 1867-8, 1868-9, 1869-70) 2 Mersey Dk. Bd. Fort Point 1859-60, 1860-61 2 | U.S. Survey. Cat Island 1848 2 bs 1872 | Ramsgate 1864 2 | Admiralty. Karachi ... 1870-1 2 | Parkes. Portland 1851, 1857, 1866, 1870 2 Sir J. Coode. 1876 | Hilbre Island 1858, 1859, 1860, 1861, 1862, 1863, 1864, 1865, 1866, 1867 2 Mersey Dk. Bd. Karachi ... 1871-2, 1872-3 2 Parkes. San Diego 1860, 1861 2 U.S. Survey. Fort Clinch 1860-1 2 7 W. Hartlepool . 1858-9, 1859-60, 1860-1 2 — Port Leopold 1848-9 2 | Clark Ross. Beechy Is. 1858-9 2 | Capt. Pullen. Brest 1875 2 | French Marine, ‘ Toulon 1853 2 a 1878 | Freemantle 1873-4 2 | Admiralty. Port Louis 1838-9 = Sy (Mauritius) " Port Louis 1842 - pas (Berkely Sd.) Toulon ... He 1847, 1848 French Marine. Marseilles 1850-1 = Pr Malta 1871-2 — | Ad: Cooper Key British Work on Harmonic Analysis of Tidal Heights—(cont.). ON HARMONIC ANALYSIS OF TIDAL OBSERVATIONS. 343 Date f o Publi- cation 1889 1902 Unpublished Station Dates of Record Analysed S pee Ror a Dover 1883, 1884, 1885 3 | Bd. of Trade. Ostend 1883, 1884, 1885 3 | Belgian Minis- | try of Public | Works. Singapore 1882 2 == Hong Kong 1883 2 —- Princess Royal Har. | 1876-7 4 | Admiralty. Neweastle (N.S.W. a) 1900 4 ae Ballina 1898 4 9 Hong Kong 1889 4 | Chinese Customs Swatow . 1897-8 4 b3 Wampoa 1894-5 4 - Brisbane 1865-6 4 | Admiralty. Sydney ees 1888 4 ” Cooktown 1890 4 ef Cairns Harbour 1892-3 4 99 Liverpool 1902 2 | Mersey Dk. Bd. Liverpool 1902 2 Ross Island 1902-3 5. | ‘ Discovery’ Exp. 8. Orkneys 4 1903 6 | ‘Scotia ’ Exp. Port Chalmers,N. re 1901 4 | Admiralty. Port Lyttleton,N.Z. 1901-2 4 or Wellington, N.Z. 1901 4 A Auckland, N.Z.... 1900-1 4 5 Wei-Hai-Wei 1898-9 4 res Woosung... 1902 4 | Shanghai Customs. Ross Island 1908 5 | ‘ Nimrod’ Exp. Ross Island 1902-3 5 | ‘ Discovery ’ Exp. Brisbane 1908 6 | Local. Dover 1910-11 2 | Admiralty. Cuxhaven 1841-2 2 | Admiralty. Gibraltar... — 2 Si Oban... 1910-11 2 > Shatt-el- Arab — 2 35 Stromness 1910-11 2 BA Georgetown 1915-16 2 | Colonial Office. |, (Brit. Guiana) London Bridge ... 1911, 1912 2 | Port of London. Tilbury Dock ... _ 2 a Royal Albert Dk. — 2 Pe Southend — 2 7 Immingham 1911-12 2 | G.E. Railway. Avonmouth 1910-11, 1911-12 2 | Bristol Harbour Penang ... 1906-7 2 | Local. Hong Kong 1887, 1888, 1889 2 ‘5 Port Swettenham — 2 3 Authorities for Analysis. 1. Thomson and Roberts. 3. E. Connor, 5. Darwin. 4, Wright. 6. Selby and Hunter. * 2. Roberts. The number of stations considered is 57; the aggregate record analysed amounts to about 90 years. 344 REPORTS ON THE STATE OF SCITENCE.—1920. British Work on Harmonic Analysis of Tidal Currents. Sc, off Caithness. E,, off Northumberland. Smith’s Knoll, Lightship off Norfolk. Varne, ” Outer Dowsing, 5, Swarte Bank, as K, further out than E,. E52, further out than KH. in Straits of Dover. off Lincoln. Date Station Analyses made 1911 Se M, at 3 depths. E, Mp, So 2” 3 ” Smith’s Knoll IMG! “Fao! ., Varne Mal ,f26f 3, 1912 E Mie ss-mele eas Smith’s Knoll Mz at same depths as in 1911. Varne Mp ” ” ” ” 1913 H52 Mz at 2 depths. Outer Dowsing 1S a Sa Swarte Bank M.,6 «4, Smith’s Knoll M, xt 7 of depths taken in 1911, 1912. Varne Mz, at same depths as in 1911, 1912. about midway between Grimsby and Texel. The number of stations considered is 8 ; the aggregate duration of the observa- tions analysed amounts to about 34 weeks. Indian Work on Harmonic Analysis of Tidal Heights. Gauge Records Analysed. Station Dates of Record Station Hanstal ... 1874 to 1875 Galle Navanar... ae oe Libis Colombo... Okha Point wee >, », 1875, 1905 to 1906 Cochin Bombay (A.B.)... | 1878 ,, present Cocanada Karwar ... Ae sh 93 LSS Chittagong Beypore ... 3s 95 1884 Akyab ... aoe Pamban Pass 3. «9 1882 Bombay (P.D.)... Aden 1879 ,, present Vizagapatam >> »» 1885 Tuticorin Madras 1880 to 1890, 1895 to present|| Bhaunagar Rangoon +> 9) present Mergui Amherst... a ot LSSO Trincomalee Moulmein » os 9 1909topresent|| Minicoy ... Port Blair ss 95 present Bushire ... Karachi ... UES ay 2 5 Muscat Negapatam +» », 1882, 1886 to 1888 || Diamond Is. False Point >> >», 1885 Suez Duoplat ag >» » 1886 Perim Diamond Har. ... 56, ule taueates Porbandar bes Kidderp ore ss 3, present Port Albert Victor Elephant Pt. 1884 ,, 1888 Bassein ... a Goa 1884 ,, 1889 Personal Observations Analysed. Port Albert Victor, 1881 to 1882; Porbandar, 1893 to 1894. Dates of Record 1884 to 1890 ” 29 9 1886 ,, 1892 a3 1, 1891 9 9? ” 1887 ,, 1892 1888 ,, present 990099 1893 1889 ,, 1894 99 ” 9 1890 ,, 1896 1891 ,, 55 1892 ,, 1901 1893 ,, 1898 1895 ,, 1899 1897 ,, 1903 1898 ,, 1902 ” 9 9 1900 ,, 1903 1902 ,, 1903 Besides the above a record for Basrah was analysed in 1916-17 and the published with those for the Indian stations. results nF ON HARMONIC ANALYSIS OF TIDAL OBSERVATIONS. 845 The number of stations considered is 43. The aggregate amount of record analysed up to the present amounts to about 480 years. Canadian Work on Harmonic Analysis of Tidal Heights. Gordon’s Analyses. The results were published in 1887. Date and Length Date and Length Station of Record Station of Record Port Burwell ... | 1885, 2 weeks Stupart’s Bay ... | 1886, 2 weeks Ash Inlet Sca f 1SS0R 4s se Port Laperriére ... el eg at Nottingham Is. ... a an Analyses made for Survey. The results are mostly unpublished. 5 Date of beginning and - Date of beginning and Station Length of Record Station Length of Record Halifax ... ... | 1851, 13 years Forteau Bay... | 1898, 5 years Quebec ... ... | 1894,18 ,, Vancouver oder 902d pos,; St. John, N.B. ... spt DORs Port Simson ... sped Ohenrsys St. Paul Is. dx. ShokS98,iN7- sass Clayoquet ... | 1905, 9 ,, Sand Heads ans Pes elineti ce Prince Rupert ... | 1906, 8 ,, Victoria, B.C. ... gu Abiniss Wadhams oi woah Ong S Father Point ... | 1897,15 ,, Charlottetown ... | 1907, 8 ,, Point Atkinson... | 1912, 5 ,, The number of different stations considered is 19, Point Atkinson being prac- tically identical with Sand Heads, which it has replaced; the aggregate length of record analysed amounts to about 160 years. Australian Work on Harmonic Analysis of Tidal Heights. Analyses Made. Date of Publi- Station Date of Record Authority cation 1892 | Port Adelaide ok 1889-90 Chapman & Inglis. 1894 ” oe ”? ” ” 1898 af oa 1889-90, 1893 “t bP 1902 Port Darwin vee 1896 by is 1914 | Freemantle nec 1908-9, 1909-10 Cooke. “th °3 ae 1911, 1912 Curlewis. + Port Hedland 300 1913 Hp The aggregate length of record analysed amounts to about eight years. Work done in New Zealand on Harmonic Analysis of Tidal Heights. Analyses made by the Survey. The prefixed dates are those of publication, the others those of the records. 1911 Wellington. 1912 Auckland, 1914 Dunedin, 1909 1908-9 1911-12 346 REPORTS ON THE STATE OF SCIENCE.—1920. The Urgent Need for the Creation within the Empire of a Central Institution for Training and Research in the Sciences of Surveying, Hydrography, and Geodesy. By Dr. E. H. Grirriras and Major E. O. Henrict. (Paper opening joint discussion in Sections A and E, August 27. Ordered by the General Committee to be printed in extenso.) Good maps are necessary for the development of a country, for such pur- poses as defining property boundaries, limits of mining and other concessions, and so on, as well as for such engineering purposes as railway, road, and canal schemes, hydro-electric schemes, water supply, irrigation, &c. The importance of good charts, as well as reliable information as to tides and currents, hardly needs emphasising. An incorrect or out-of-date chart will cause losses due to delays to shipping, even if it does not lead to more direct loss. Anything that will assist in the production of up-to-date and accurate charts is of great and direct benefit to the shipping industry, and through it to the nation. Even when such work has once been completed there is no finality, as both maps and charts require periodical revision at more or less frequent intervals, according to circumstances. The economical and speedy production of such maps and charts necessitates a thorough knowledge of the principles on which all survey work is based, and of the best means of applying such principles under varying conditions. Apart from revision work, there is still a very great deal of survey work waiting to be carried out. Enormous areas still exist in the Empire which are surveyed very inadequately or not at all. Very large sums have been misapplied in the past owing to a. lack of appre- ciation of the. principles which should underlie all survey work. The following quotation from the official account of the ‘Cadastral Survey of Egypt,’ by Captain H. G. Lyons (Cairo, 1908), is an example of this: ‘Surveying has been carried on in Egypt to a considerable extent during the last ninety years, and the work of Muallim Ghali and M. Masi, 1813-1822, of Mahmud Pashael Falaki, 1861-1874, of the cadastre of 1878-1888, of the Hydrographic Survey of 1889-1898, amounting to a total of some forty years’ work on the geographical measurement of the country, had been accomplished before the cadastral survey, which has just been completed, commenced. That more perma- nent results were not obtained from them is mainly due to want of scientifically organised control and supervision, so that inferior work was not detected, and the standard of accuracy was allowed to fall below that which was necessary in so densely populated a country. The circumstances of the time have usually been responsible for this, and want of funds, urgent demands for maps to be prepared within a minimum length of time, and other similar causes led to much repetition of work without producing reliable maps of the country. ‘During the time that the present Survey Department has been engaged in measuring the cultivatable lands in Egypt, much inconvenience has been experienced from the want of any complete account of these earlier surveys. . . . When the formation of the Survey Department was undertaken in, 1898, no complete account existed of the work of this kind which had been previously undertaken. References to it existed in various reports, but the detailed information concerning the methods employed, their cost, the recruiting and training of staff, and relative values of different ways of executing the work was not available. There was no time then to undertake its compilation, but had such a work existed, subsequent work would have been greatly expedited and facilitated, and a considerable economy would have resulted.’ The Egyptian Survey of 1878-1888, mentioned above, cost some £360,000, and produced incomplete maps of some 2,000 square miles. Almost the whole 4 7 ON SCIENCES OF SURVEYING, HYDROGRAPHY, AND GEODESY. 347 of the work had to be repeated in 1892-1907, when, owing to the adoption of proper methods, and in spite of many difficulties, some 13,000 square miles were satisfactorily mapped at a cost of under £450,000. The methods to be adopted depend upon circumstances, the nature of the country, and the objects of the survey. The difficulties to be overcome vary in different parts of the world. The experiences of the various surveyors have been published in their records and reports, but these are not in an easily accessible form, nor is there any general index or summary to be found. The originals are circulated to a limited number of persons and institutions, and are buried in libraries, even if their existence is not forgotten. When a new difficulty arises in any survey it has to be tackled de novo, though it is quite likely that similar circumstances have arisen before. In such a case it is probable that the surveyor in question does not know of it, and even if the reports are accessible to him (which they frequently are not) the actual information he wants is most etfectually buried. This leads to much waste of effort, as there is no central body to which he can refer. As regards existing Departments and Institutions, the Dominion, Indian, and Colonial Surveys are all independent, and, broadly speaking, train their own staff. There are, however, good survey schools in some of the Dominions. The Ordnance Survey produce their well-known maps, which are revised eriodically, and they are so complete that no extensive survey work is required by outsiders in this country. This accounts for the lack of attention paid to the subject outside Government Departments, but the result has been that the development of the science of surveying has largely stagnated in this country, the centre of the Empire. There is, therefore, a distinct need for a school and institution where students can be trained in the principles of survey work, and where the subject is studied as a whole. This school would also serve as a central information bureau, enabling the scattered’ surveyors of the Empire to keep in touch with developments, and to which they could apply for information and assistance. It might seem at first sight that this could and should be undertaken by a Government Department, but this is hardly possible for various reasons. There is no central authority which deals with the Government Surveys of the Empire, though a link is kept between the Colonial (as distinct from the Dominion) Surveys by the Colonial Survey Committee. The various Surveys and Departments naturally have to consider their own immediate needs first; they are usually short of funds, and consequently are not in a position to carry out the work now being discussed. Even if a central authority were formed for this purpose it could deal only with Government Surveys, and could not train surveyors and engineers for private work. There seems little doubt that most of the Government Surveys would wel- come a school from which they could recruit their staff, and an institution to which they could apply for information, and which could keep them in touch with the activities and progress in other parts of the world. The existence of such an establishment would also encourage the production of improved designs of instruments, and the invention of new time-saving devices; there have been many such improvements of late years, but mostly from abroad—e.g., Invar tapes and wires for base measurement (France), improved levelling instrument (Germany). There are also many developments in view which require working out—e.g., the use of wireless time signals for the determination of longitude in the field, survey from aircraft, &c. At present makers have little inducement to bring out new and improved patterns of instruments; their largest customers are engineers, who as a rule have had a very elementary training as surveyors, and are shy of adopting a new instrument or method. The above remarks apply particularly to land surveying, but are largely true also of hydrographic work. India and Canada have their own Hydrographic Services, but apart from this the Hydrographic Department of the Admiralty has to deal with all the seas and coasts of the Empire, and also with such others as are not dealt with by their own Governments. The task is a large one, and the resources available are all too small for the work. There is much work waiting to be done, and anything that assists in getting this work done quicker 348 REPORTS ON THE STATE OF SCIENCE.—1920. and better will be of great value to the shipping industry and the country as a whole. Even in home waters there ismuch to be done, if only due to the changes continually taking place in all estuaries. The Thames, the Humber, Portsmouth, Plymouth, and Liverpool have to be resurveyed annually. The Bristol Channel is badly in need of resurvey, which it is hoped will be carried out shortly (it was last done about 1890). The approaches to Liverpool, the Solway Firth, and the Clyde badly need revision. Most of the East Coast of England and the North Sea has not been surveyed for fifty years, and some of the work is as old as 1830. Apart from the shifting of sandbanks, &c., much of the earlier work is not up to the standard of modern requirements. As regards the rest of the world, the coast of Brazil has not been surveyed since about 1852, and that survey suffered from the poor facilities available at the time, and is very out of date. The approaches to Monte Video have not been done since 1849, and the charts are bad. The Falkland Islands are partly unsurveyed, and South Georgia and the South Shetlands almost entirely so. The Straits of Magellan, other than the main routes, are largely unknown. The coasts of China are yet imperfectly charted ; even the approaches to Hong Kong are incomplete. Siam and the Straits Settlements require resurvey ; the charts are not up to modern requirements and are out of date. The Red Sea coasts are at present almost entirely charted from the original sketch surveys. The Grecian Archipelago, the Dardanelles, and the Black Sea all require resurveying. There is no school where hydrographic surveyors can receive instruction in the principles and theory of their work, and no staff available for studying methods and instruments and bringing them up to date. The Hydrographic staff of the Admiralty is recruited from volunteers amongst the younger officers of the Executive Branch of the Royal Navy who have passed in navigation. They learn their surveying in the surveying ships while work is in progress, and the staff of trained surveyors is at present so limited that they can give little instruction to the beginners. Many officers, after serving in a surveying ship for two or more years, return to ordinary duties afloat, or specialise in other branches where their knowledge of survey work is of great benefit to them. The remainder are advanced in rank with the officers of H.M. fleet. The existence of a school where the theoretical side of the question could be studied would be of great benefit to all. The principles involved in survey are the same, whether applied by land or sea, and the instruments are largely the same. One establishment could usefully study and give instruction in both sides of survey work. Survey cannot be carried out over large tracts of country without considera- tion of the science generally known as geodesy, which is really only survey as applied to the earth as a whole. The problems inyolved in this require not only world-wide data but high mathematical skill. Problems interconnected with these are those concerning the tides and terrestrial magnetism, both of great importance to navigation. These, again, connect with the study of the earth’s structure in its wider sense, and so connect with seismology and geology. These problems may all be summed up in the word geophysics. While a knowledge of geophysics is not necessary for every surveyor, no survey authority can function satisfactorily without it. At the same time few such authorities have the staff available for its proper study. A central institu- tion, which could be referred to for information, would add greatly to the efficiency of the Survey authorities. The need for a British Geodetic Institute is admitted by all who are acquainted with the nature and importance of the pressing Imperial and gcientific problems which depend on the great surveys. The study of such problems has hitherto been left, in characteristic British fashion, to the initiative of enthu- siastic individuals or neglected altogether. Take, for example, the case of the tides, so vital a matter to our sailors. While the late Sir George Darwin still lived it could at least be said that one master-mind was devoted, with some approach to continuity, to the study of the great problems which must be attacked and solved if tidal prediction is to advance beyond its present elementary and scrappy state, but since his lamented death in 1912 the subject-has lacked attention. At the request of the B.A., Prof. Horace Lamb recently reviewed the whole ON SCIENCES OF SURVEYING, HYDROGRAPHY, AND GEODESY. 349 situation with regard to tides, and in a masterly report indicated the number and importance of the problems awaiting solution. Problems comparable in insistence are connected with the land surveys of our Empire, and a similar review of the general situation, also initiated by the B.A. under the stimulus of war, drew attention to the pressing need of some determined effort to attack them. The report opened with this cogent sentence : ‘ There is no institu- tion, association, or department whose business it is to deal with the higher Geodesy.’ Consideration of the report by a special committee, subsequently enlarged, developed in the direction of urging the establishment of a Geophysical Institute. The need for such an Institute has been formally recognised as urgent by the Conjoint Board of Scientific Societies (formed during the war for the study of urgent questions), who appointed a small executive com- mittee (which included the President and Secretary of the Royal Society) to press for the immediate establishment of such an Institute. A committee promoted by the ex-Vice-Chancellor of Cambridge was subse- quently formed, and issued an appeal calling attention to the national import- ance of the matter. Amongst its members are to be found the Astronomer- Royal, the President of the Royal Society, Sir Charles Parsons, Col. Lyons (formerly Director-General of the Survey of Egypt), Prof. Turner, Sir Charles Close (Director-General of the Ordnance Survey), Sir Napier Shaw, Sir Joseph Larmor, and other authorities on scientific matters. In an appeal issued by that committee it is stated that ‘It is the widespread British territories which are most closely concerned in the great international surveys of the future, and indeed of the past; and the consolidation and exten- sion of their special surveys is most necessary to the solution of the Geophysical problems of the world. . . . It would be a matter for regret if, from omission of the relevant scientific development at home, British official surveyors were again compelled to rely on the Prussian Geodetic Institute at Potsdam for information with regard to international work in the higher Geodesy.’ The following are extracts from letters received by this committee :— Admiral Parry (then Hydrographer to the Admiralty)—‘ Such an Institution would be warmly welcomed by the Hydrographic Department, and it is sug- gested that courses of instruction should be available, not only for geodesists and land surveyors, but also for the cognate Naval Service, so that these services would be able to collaborate more closely than at present as regards geodetic problems, and as regards tidal problems would assist in bridging the gap between the practical and theoretical sides which at present exists. I am convinced that the establishment of such an Institute would be of the greatest benefit to the Empire at large, more especially as the latter is so widely distributed, and it seems most essential that there should be such an Institute where surveyors, geodesists. etc., of the Empire could not only receive instruc- tion but to which they could also refer any practical and theoretical problems which may arise.’ A letter from the Army Council states that—‘ The war which is now drawing to a conclusion has shown the great value to the Army of trained surveyors from the skilled geodesist to the topogranher and draughtsman. I am to say, therefore, that the Council would view with great satisfaction the establishment of an Institute which would encourage the study of Geodesy and Survey in all its branches, and that such an Institute would undoubtedly be of immense assistance to that study of survey work which it is the wish of the Council to promote in the Army.’ It will be seen from the above that both the Navy and Army authorities are anxious to see a combined Survey and Geodetic School and Institute established. Sir Charles Close (Director-General of the Ordnance Survey) writes—‘ I have no doubt that it is in the national interest that a Geodetic Institute should be created. and I think it would be a very satisfactory arrangement if it were estahlished at Cambridge. and. in connection with it, a Professorship of Geodesy.’ We think it would be difficult to find, in any scientific matter. greater unanimity amongst all the authorities concerned therein. We trust that suffi- cient evidence has been given both as to the national importance of the subject and the urgency of the need for action. We await the advent of the ‘ Vivus Benefactor,’ for—as already indicated—there is a consensus of opinion that 350 ‘REPORTS ON THE STATE OF SCIENCE.—1920. such an Institution should be established within a University by private bene- factions, although assistance might, as a consequence, be forthcoming from national funds. The wide ramifications of Survey, Geodesy, and Geodynamics into mathematical, physical, and engineering sciences call for their study in a University, rather than in a Departmental, atmosphere. ‘ Undue withdrawal from the Universities to official special Institutes of the men who show promise of ‘power would hamper their own development by removal from their proper environment; moreover, it would weaken the efficiency of the Universities as the national nurseries of scientific ability and genius at a time when, by more intimate relations with the Dominions and increased contact with other nations, they ought to be preparing for the discharge of imperial functions.’ 1 We trust that this conference of the Physical and Geographical Sections will forward to the Council of the B.A. a resolution calling attention to the urgency of this matter. 1 Sir Joseph Larmor. SECTIONAL TRANSACTIONS.—A. 351 SECTIONAL TRANSACTIONS. SECTION A.—MATHEMATICAL & PHYSICAL SCIENCE. (For references to the publication elsewhere of communications entered in 9. 10. 11. 12. 13. the following list of transactions, see p. 380.) Tuesday, August 24. Presidential Address by Prof. A. S. Eppinaton, F.R.S. See p. 34. Mr. J. Eversuep, F.R.S.—Measures of the Shifts of the Fraunhofer Lines and their Interpretation, particularly with relation to the Einstein Theory. Major P. A. MacManon, F.R.S.—A New Binomial Theorem and its Arithmetic Interpretation. Prof. H. Hiuvron.—Plane Algebraic Curves of Degree n with a Multiple Point of Order n—-1, and a Conic of 2n-point Contact. Prof. G. H. Bryan, F.R.S.—The Graphical Solution of Spherical Triangles. Mr. T. C. Lewis.—lIs there in Space of three Dimensions an Analogue to Feuerbach’s Theorem? Is there any- thing corresponding to the Hart System? Wednesday, August 25. Dr. F. W. Aston.—Mass Spectra and the Constitution of Chemical Elements. Sir E. Rurwerrorp, F.R.S.—The Building up of Atoms. Prof. R. Wuippineton.—The Ultra-Micrometer. Lieut.-Col. F. J. M. Srrarron.—Spectra of Nova Aquile III. Rev. Father A. L. Contin, 8.J.—Comparison of Drawings of Solar Facule and Photographs of Calcium Floccult. Thursday, August 26. Discussion on The Origin of Spectra, opened by Prof. A. Fowter, F.R.S., and Prof. J. W. Nicuouson, F.R.S. Report of Seismology Committee. Prof. H. H. Turner, F.R.S., and Mr. J. J, SHaw. See p. 210. 352 SECTIONAL TRANSACTIONS.—A. 14. Sir Outver Lopas, F.R.S.—Controversial Note on Popular Relativity. This note concerns the assumed necessary constancy of the observed velocity of light in free space, as contrasted with the universally admitted constancy of its true velocity. The author contends that there is no experimental evidence for the dogma that wave-fronts are concentric with a travelling observer initially situated at the source. The Michelson- Morley experiment is consistent with such concentricity, but does not necessitate it. The FitzGerald-Lorentz contraction of matter is a perfectly valid alternative explanation. Einstein’s equations exercise no physical discrimination and are consistent with either mode of expression. In interpretin them verbally it is safer for a physicist to postulate a special property of matter than to attempt to foist complications upon time and space, 15. Prof. F. Horton and Miss A. C. Davies.—The Tonisa- tion of Atmospheric Neon. It has been found? that the following are critical electron velocities for atmospheric neon :—11'8 volts and 17°8 volts for the production of radiation, and 16-7 volts, 20-0 volts, and 22:8 volts for the production of ionisation. The condi- tions under which the different critical points were indicated showed that the radiation velocity, 11°8 volts, is associated with the ionisation velocity, 16°7 volts, and that the radiation velocity, 17°8 volts, is associated with the ionisation velocity, 22:8 volts. No third critical velocity for radiation, corre- sponding to the ionisation velocity, 20°0 volts, was detected, but it is possible that such a critical velocity occurs too close to one of the other radiation velocities to be distinguished separately. The conditions under which the various points were obtained also showed that none of the critical velocities mentioned can be attributed to the displacement of a second electron from an already ionised atom. Neon is the only gas so far investigated which has shown more than one critical velocity for the removal of a first electron from the atom. Further information as to the ionisation of neon was sought by observing the spectrum of the luminosity produced in the gas as the electron velocity was gradually increased ; for on the generally accepted view the line spectrum of a gas results from the recombination wHich occurs when ionisation has taken place. It was found that the lines of the first and second subordinate series types never appeared Below 22°8 volts, but that under certain conditions the lines of the Principal series type came in at 20°0 volts. No lines in the visible spectrum were ever observed below 20°0 volts, although the earlier experiments show that considerable ionisation must have been occurring. The results of the ionisation experiments might be inter- preted as indicating that atmospheric neon is a mixture of different elements, since isotopes would be expected to have the same critical velocities for electrons. Such a supposition is, however, not borne out by the investigation of the spectrum of the luminosity produced in atmospheric neon, for if there were more than one element present it would be expected that the complete spectrum of the element of lower ionising velocity (including some lines in the visible spectrum) would 1 Proc. Roy. Soc. A, 1920. ae 16. 17. 18. 19. 20. 21. 22. 23. SECTIONAL TRANSACTIONS.—-A, B. 358 be obtained for lower electron velocities than the spectrum of the other element, and this was not found to be the case. We therefore conclude that the different critical velocities found for neon correspond to the displacement of differently situated electrons within the atom, or, in other words, that the external electrons in neon are not all symmetrically situated about the nucleus. Report of Committee on Gravity at Sea. Friday, August 27. Prof. S. CHapman, F.R.S.—Terrestrial Magnetism, Aurore, Solar Disturbance, and the Upper Atmosphere. Dr. A. EK. Oxtey.—Magnetism and the Structure of the Atom. Mr. J. H. SuHaxsy.—Vapour Pressures. Reports of Committee on Tides. See p. 321. (1) Prof. ProupMan.—Harmonic Analysis. (2) Mr. A. T. Doopson.—Prediction. Dr. P. V. Weuus.—The Thickness of Stratified Soap Films. Mr. H. P. Waran.—A New Type of Interferometer. Joint discussion with Section E on Geodesy. See p. 346. SECTION B.—CHEMISTRY. (For references to the publication elsewhere of communications entered in 1920. the following list of transactions, see p. 380.) Tuesday, August 24. Presidential Address by Mr. C. T. Heycocx, F.R.S. See p. 50. Capt. A. DessoroucH.—Industrial Alcohol. Wednesday, August 25. Joint Meeting with Section A for the discussion of papers 7 and 8 in the programme of that Section (which see). Discussion on Lubrication.—Mr. A. E. Dunstan, Mr. H. M. Weuus, Mr. J. KE. Sourncomse, Mr. H. T. Tizarp, Prof. W. C. McC. Lewis. Thursday, August 26. Papers on the Metallurgy of Tungsten—Mr. J. L. F. Voge, Prof. C. H. Descu. Electrolytic Zinc.—Mr. 8. FIELD. Dr. R. V. Stanrorp.—(a) New Method for the Estima- tion of Carbon by Combustion in Organic Compounds, using very small quantities of substance. (b) Hstima- tion of Amino-acids, using very small quantities of substance. AA 304 SECTIONAL TRANSACTIONS.—B, C. 7. Report of Committee on Fuel Economy (Prof. W. A. Bone, F.R.S.), and Discussion thereon. See p. 248. Friday, August 27. 8s. Dr. J. 8S. OwEens.—Researches on Atmospheric Pollution and its Measurement. 9. Prof. F. M. Jancer.—Research Work at High Tempera- tures, and the Determination of Surface Tension and Electrical Conductivity between —100° and +1650° C. The following excursions were arranged for members of the Section: Melingriffith Tinplate Co.; South Wales Indiarubber Co.; Cardiff Gas Co.; Cardiff Dowlais Works; exhibits, etc., in Chemical Laboratories, Mental Hospital, Radyr; Powell Duffryn Co. ; Tharsis Sulphur and Copper Co. SECTION C.—GEOLOGY. (For references to the publication elsewhere of communications entered in the following list of transactions, see p. 380.) Tuesday, August 24. 1. Presidential Address by Dr. F. A. Barusr, F.R.S. See p. 61. 2. Prof. A. Huperr Cox.—Address on the Geology of he Cardiff District. 3 Dr. J. W. Evans, F.R.S.—The Origin of the Alkali Igneous Rocks. These rocks, distinguished by unusually high proportion of alkalies, relatively to alumina and lime, occur mainly where the Crust of the earth is thick, the heat-gradient low, and there has been no folding since remote times. Magmas appear to have reached the sut face by fault fissures from great, depths where high pressures are associated with compara- tively low temperatures. Crystallisation proceeding under such circumstances, there would be an early formation of minerals with small molecular volumes, garnets, kyanite, epidote, and zoisite, minerals rich in lime and alumina. Zoisite may be regarded as the high-pressure representative of anorthite, but there is no corresponding representative of albite or orthoclase. Consequently we should expect a residual magma exceptionally rich in alkalies which would furnish the material necessary for formation of alkali rocks. 4. Reports of Research Committees. See p. 261. Wednesday, August 25. 5. Joint Meeting with Sections D and K. Discussion.— Mendelism and Paleontology: The Factorial Inter- pretation of Gradual Changes, especially when New Characters appear late in the Individual Life-cycle. SECTIONAL TRANSACTIONS.—C. 355 Dr. F. A. Baruer, F.R.S. :— The question posed. Can characters be regarded as independent, i.e. as manifestations of independent factors in the germ? Does evolution take place solely by addition or loss of such factors? Is there not also a gradual modification of the body, resulting in a continuous transition? Palzonto- logists find such transition to be the rule in those cases where the geological record is sufficiently complete. (See President’s Address, Section C, heading ‘ Continuity in Development.’) Paleontologists support the theory of Recapitulation, and believe that, in many cases, gradual modification of the adult and senile body is, in the course of race-history, pushed back to earlier growth-stages. (See President’s Address, Section C, heading ‘ Recapitulation.’) Can such cases be explained by independent factors in the germ? Does not that hypothesis involve, first, an alteration of the germ through change in the body; secondly, the determination of that germinal change in a direction harmonious with bodily change? Dr. R. Ruaates Gatss :— According to mutationist hypothesis, germinal characters arise as alterations of single elements of the germ plasm. This conception avoids the difficulties involved in considering the change as due to the loss or addition of a factor. It recognises on the one hand the solidarity of the germ plasm as a whole, and on the other the independent origin of variations in its several parts. Such variations are termed karyogenetic, since they apparently arise in the nuclei and are perpetuated by mitotic division. Mutations of this nature are almost universal amongst wild plants and animals, and some of them are so small that for general purposes they are practi- cally continuous. They differ from the Darwinian conception of continuous variation, however, in that (i.) they do not arise in any regular order, (ii.) they are inherited as separate units. But Recapitulation is an almost equally widespread phenomenon in animals, and to a less extent in plants. The recapitulation in animal embryos, and in such fossil groups as the Ammonites, implies the addition of terminal stages to the development of the organism. From the standpoint of organic structure this process is clearly different from a mutation by which the nuclear unit is modified throughout the organism. Recapitulatory characters thus fall into two groups : (i.) embryonic, which appear always to imply adap- tation of the organism to different conditions, and are best explained by the neo-Lamarckian principle; (ii.) orthogenetic, which appear late in the life-cycle but are germinal in origin and non-adaptational. Prof. J. HE. Durrpen.—Mendelism; Paleontology ; Evolution. Recent investigations in genetics in general give support to the factorial hypothesis, namely, that the characteristics of the body are represented in the germ plasm, in all proba- bility in association with the chromosomes. Supporting evidence is forthcoming from sex, crossing-over and localisa- tion. Any hereditary change in an organism must therefore be associated with factorial change in the germ plasm. Casual mutations readily admit of Mendelian interpretation, but evolution in general does not take place by changes of this kind. Evolution of species often seems to call for a sintilar change in the whole assemblage of individuals within an area, while paleontology and the study of numbers of AA2 356 6. 7 8. SECTIONAL TRANSACTIONS.—C. related forms calls for gradual successional changes in the same direction as regards any particular structure (ortho- genesis). Mendelian experiments do not yet afford any great support for either of these demands. Observed mutational changes do not call for environmental influence, and are wholly apart from any adaptive considerations; natural selection plays no part in the origin or preservation of variations, but may be eliminative. It is highly questionable whether somatic or environmental influences can modify the germinal factors in definite directions, but disruptive changes and gradual loss of factorial vigour, or perhaps senility, may be contemplated, continued over long ages. As the common germ plasm of a race may at any one time be presumed to be in somewhat the same condition, evolutionary changes on somewhat similar lines may be expected. Prof. A. Drenpy, F.R.S. Thursday, August 26. Dr. T. Frangurn Sisty.—The Old Red Sandstone of the Mitcheldean District, Gloucestershire. Mitcheldean lies on the Gloucestershire-Herefordshire border ten miles west of Gloucester, and in the latitude of the Breconshire Beacons. In this neighbourhood persistent westerly dips determine an outcrop of the whole of the Old Red Sandstone, with a thickness of some 7,500 feet, in a band scarcely two miles wide, bounded on the east by the Silurian strata of the May Hill anticline and on the west by the Carboniferous of the Forest of Dean coal-basin. The sequence of strata determined in this locality offers a possible key to the wilderness of Old Red Sandstone in Herefordshire. Prof. W. M. Furypers Perriz, F.R.S.—The Continuance of Life on the Earth. If by any process of aggregation the earth has been at a ved heat, all the lime and soda would be combined with the silica (now sandstone) and all the carbonic and hydrochloric acids would be in the atmosphere (now locked up in limestone and salt). The changes from that condition would consist in the acids gradually decomposing the silicates; at present there is only a minute fraction of the original carbonic acid left in the atmosphere. The decomposition of a few more inches of silicates over the globe would exhaust the carbonic acid, and life could not exist. This may take place in a few hundred thousand years, and such is the limit to vegetable and therefore to animal life, irrespective of solar cooling. The amount of carbon in the strata is probably enough to combine with all the oxygen of the air; hence land- breathing animals were impossible until after the carbon had become separated and left oxygen free. This agrees with the appearance of air breathers after the Carboniferous age. Dr. A. E. Trueman.—The Liassic Rocks of Somerset- | shire and their Correlation. The Liassic iocks of Somerset are thin but richly fossili- fercus, yielding many large Ammonites. When followed towards the Mendips there is. considerable reduction in thickness and marked lithological change. At several localities a white limestone resembling the Sutton Stone of Glamorgan is seen to rest on the Carboniferous Limestone ; a eo nts eran» SECTIONAL TRANSACTIONS.—C. 357 it is developed at various horizons and usually contains no Ammonites, but correlation can be made by means of species of Ostrea and Gryphea. In the numerous exposures near Radstock many non-sequences can be located, and maps showing the movement of intra-Liassic folds have been prepared, 9. Dr. J. K. Cuarteswortu.—The Glaciation of the North- West of Ireland. The major part of the region investigated, including the Donegal Highlands and the Sperrin Mountains, was never invaded by the Scottish ice as currently supposed, but the Donegal mountains, in particular the Barnesmore Hills, formed a most powerful centre of radiation, whence ice streamed westwards to the Atlantic and eastwards over the Sperrin Mountains to Cookstown and beyond. In a south- easterly direction the ice passed obliquely across the Clogher Valley in Slieve Beagh to the Central Plain of Ireland, where was located the ‘central axis’ of Hull and Kilroe. This axis of dispersal existed at no period of the glaciation. 10. Mr. L. Dupury Stamp.—On Cycles of Sedimentation in the Hocene Strata of the Anglo-F'ranco-Belgian Basin. The Eocene deposits of the great Anglo-Franco-Belgian Basin can be grouped naturally into a series of cycles of sedimentation—the Montian, Landenian, Ypresian, Luetetian, Ledian, and Bartonian. Each cycle commences with a marine invasion and passes from marine to estuarine and continental conditions. In England the changes are closely connected with the gentle, intermittent wprise of the Weald. Friday, August 27. 11. Dr. J. W. Evans, F.R.S.—The Geological Structure of North Devon. In early Permian times the Devonian and Carboniferous were thrown by pressure from the south into overfolds, with overthrust faults. A subsequent relaxation of pressure resulted in a slip back on the same fault-planes. There were also oblique tear-faults striking between north and west. A mountain region then sloped southward from the Welsh Coast to Mid-Devon and much material was transported in that direction. In the ‘Triassic period, however, the Palzozoic had, as a whole, its present contours, including the great Glastonbury and Bristol Channel depression descending to the west, and its subsidiary valleys still partly filled with Mesozoic deposits. In Tertiary times there was renewed pressure from. the south. This met with less resistance in the west, and there was consequently a relatively forward and downward movement on that side along the old tear-faults and possibly new fractures with the same general direction. In Pliocene times the land was more submerged than now and the subsequent emergence seems to have con- tinued in most places till a comparatively recent date. 12. Prof. W. L. Braaa.—Crystal Structure. The investigation into crystal structure, which has been made feasible by the discovery of the diffraction of X-rays by crystals, has led to a determination of the precise positions of the atoms in a number of the simpler crystalline forms. Recent theories of atomic structure, such ag those put forward by Bom and Landé, Debye, Lewis, and Langmuir, 358 SECTIONAL TRANSACTIONS.—C, D. are largely based on the arrangement of the atoms in crystal- line solids, since this arrangement affords an insight into the nature of the forces acting between the atoms. In such compounds as sodium chloride, it is probable that the atoms exist as ions of sodium and chlorine, and that the crystal is held together by the electrostatic attractions of these ions, thus accounting for the fact that there is no grouping of the atoms into molecules in the solid. In other compounds, such as those of two electronegative elements, the molecular arrangement persists in the solid state and the chemical com- bination appears to be of a different type from that of sodium chloride. A consideration of the distances between the atomic centres in crystals supports the conception of the two types of chemical combination. 13. Mr. D. C. Evans.—The Ordoviceo-Valentian Succession in North-east Pembrokeshire and North Carmarthen- shire. 14. Mr. Davi Davies.—Paleontology of the Westphalian and lower part of the Staffordian Series of the Coal Measures as found at Clydach Vale and Gilfach Goch, East Glamorgan. Recorded : 45,000 plants; 1000 shells; 2 insects and one fish scale. Plants yielded 154 species, shells 6 species, insects 2 species, fish scale one; 45 of these are new to South Wales and 7 new to Britain. Ecology of ten horizons : Equisetales predominate in four; Filicales and Pteridosperms in three; Lycopods in two, and Cordaitales in one horizon. When Lycopods predominate, Fern and Fern- like plants are weak, and vice versa. 37 per cent. plants are common to both series; 31 per cent. distinctly Staffordian ; 32 per cent. distinctly Westphalian. The Pennant Sandstone produced smooth round coal pebbles, giving evidence of a geological break. A significant feature is the appearance of new species at this period. SECTION D.—ZOOLOGY. (For references to the publication elsewhere of communications entered in 1. the following list of transactions, see p. 381.) Tuesday, August 24. Presidential Address by Prof. J. SrannEy GaRDINER, F.R.S. (see p. 87). Followed by a Discussion. Afternoon. 2. Prof. J. SrepuHenson.—The Polyphyletic Origin of Genera 3. in the Oligocheta, and its bearings. Prof. P. Fauven.—The Affinities of the Annelidan Fauna of the Abrolhos Islands. 5. 6. 10. 11. 12. 13. 14. SECTIONAL TRANSACTIONS.—D. 359 Wednesday, August 25. Joint Meeting with Sections C and K. Discussion on Mendelism and Paleontology: the Mendelian Inter- pretation of gradual changes, especially when new Characters appear late in the individual Life-cycle. For speakers see Programme of Section C, p. 354. Afternoon. Reports of Committees. Prof. J. E. Dusrpen.—A Caudal Vesicle and Reissner’s Fibre in the Ostrich. Mr. J. H. Luovp.—The Early Development of the Pro- nephros in Scyllium. Thursday, August 26. Discussion on the Need for the Scientific Investigation of the Ocean. Opened by Prof. W. A. Herpman, C.B.E., F.R.S. Other speakers: Prof. J. Sranuey GARDINER, BRS. Drews. Aten,” ERtS., Mr. C. Tam ReGcan, F-R.S., Prof. C. A.-Kororw, Prof. J. E. Durrpen, Sit Francis Ocitviz, Mr. F. E. Smits, Dr. EK. C. Juz. Section E (p. 361) took part in this discussion. Afternoon. Discussion on the Need for the Scientific Investigation of Fisheries. Opened by Mr. H. G. Mauvricr, C.B. Other speakers: Prof. A. Mrrx, Prof. James Joun- stone, Mr. Crawrorp Heron, Prof. G. GurLson, Dr. E. J. Auten, F.R.S., Prof. W. Garsrana, Mr. C. Tate Recan, F.R.S., Mr. Neate, Prof. J. SranLey GARDINER, F'.R.S. Friday, August 27. Prof. J. E. Durrpen.—The Pineal Eye in the Ostrich. Prof. A. Murx.—The Physiology of Migration. Prof. C. A. Kororn.—The Neuro-motor System of Cilate and Flagellate Protozoa, and its Relation to the process of Mitosis and to the Origin of Bilateral Symmetry in certain Flagellates. Dr. Cresswetut Sunarer, F.R.S.—The Influence of Salts on Growth. Mr. E. Hrron-Auten, F.R.S., and Mr. A. Karuanp.— Protoplasm and Pseudopodia. 360 SECTIONAL TRANSACTIONS.—--D, E. Afternoon. 15. Prof. C. A. Korom.—Hookworm and Human Efficiency. 16. Prof. R. W. Heaner.—The Relations between Nucleus, Cytoplasm, and External Heritable Characters in the genus Arcella. 17. Prof. E. B. Poutron, F.R.S.—A Preliminary Account of the Hereditary Transmission of a minute, extremely variable, generally asymmetrical marking in the fore- wing of the Currant Moth (Abraxas grossulariata). Saturday, August 28. Excursion to Southerndown and Merthyr Mawr. Exhibits. There were on exhibition throughout the meeting :— (a) A series of plates for ‘A Monograph of the Unarmoured Dinoflagellates,’ by Prof. C. A. Korom. (b) Living specimens of Amphidinium, by Miss C. Herpmay. SECTION E.—GEOGRAPHY. (For references to the publication elsewhere of communications entered in the following list of transactions, see p. 381.) Tuesday, August 24. 1. Presidential address by Mr. J. McFaruane. See p. 98. 2. Mr. D. Lievurer Toomas.—Some Geographical Aspects of the Distribution of Population on the South Wales Coalfield. The narrow valleys of the plateau provoke feelings of imprisonment and isolation—originally the coal attracted the raw material of industry, e.g. copper, iron—after 1850 coal was worked in the interior valleys—the Rhondda valley became populous after 1871 and caused the growth of Cardiff and Barry, Discussion opened by Dr. A. E. Trueman. Other speakers: Prof. H. J. Fururn, Mr. H. J. Ranpatu, Mr. A. E. L. Hupson, &c. 3. Dr. A. E. Trusman.—The Iron Industry of South Wales. Iron ore either hematite or ironstone nodules—the iron- stone worked all over the coalfield, but especially the east— the growth of Merthyr Tydfil—phosphatic nature caused a decline in mining—ore brought from Spain, despite transport costs the iron industry persists in its original location. Wednesday, August 25. A. Lieut.-Col. W. J. Jounsron, C.B.E., R.E.—Small-scale Maps of the United Kingdom. The demand for coloured maps is increasing. Engraving on copper for map reproduction is moribund. Of three methods in use at the Ordnance Survey that dependent on photo-zincography is probably best. a SECTIONAL TRANSACTIONS.—E. 361 ‘Ss. Mr. A. E. L. Hupson.—Some Methods of Using Ordnance Maps in School Teaching. 6. Capt. H. Autan Liovp.—The Pictorial Factor in Aérial Map Design. 7. Joint Meeting with Section L (see p. 377) in the rooms of Section L. Prof. J. L. Myres.—The Place of Geography in a Reformed Classical Course. Discussion by Mr. G. C. Cutsuoum, Mr. H. O. Bscxit, &c. Afternoon. 8. Dr. Vaucuan Cornisu.—Imperial Capitals. Paris, like other capitals, occupies a position between the centre of the country and the middle of the most important frontier—such a situation compromises between the best site for civil (pout) administration and the best site for military defence (foreign). Hacursion. Vale of Glamorgan, visiting Barry, Llantwit Major, and Cowbridge. Thursday, August 26, 9. Rev. W. J. Barton.—The Oases and Shotts of Southern Tunis. 10. Joint Meeting with Section D in the rooms of Section D (p. 359). Dr. E. C. Jez.—The Movements of the Sea. Afternoon. 11. Prof. E. H. L. Scuwarz.—The Kalahari and the Possi- bilities of its Irrigation. The Kalahari, The changed course of the Cunene river. The three great depressions. Weirs on the Cunene and Chobe and their utility for irrigation, Excursion. The Upland of Glamorgan and the Taff and Rhondda Valleys. Friday, August 27. 12. Dr. T. Asuspy.—The Water Supply of Ancient Rome. The four chief aqueducts of Ancient Rome. The Anio valley, its river and springs. Recent exploration along the course of the aqueducts—geographical considerations. 13. Joint Meeting with Section A in the rooms of Section E. Dr. E. H. Grirritus and Major Henrici.—The urgent need for the creation within the Empire of a Central Institution for Training and Research in the Sciences of Surveying, Hydrography, and Geodesy. See p. 346. 362 SECTIONAL TRANSACTIONS.—, F. Exhibit. A collection of maps illustrating various aspects of the geography of South Wales, arranged by the Cardiff branch of the Geographical Association, was exhibited in the City Hall through- out the meeting. SECTION F.—ECONOMIC SCIENCE AND STATISTICS. (For references to the publication elsewhere of communications entered in 1. the following list of transactions, see p. 381.) Tuesday, August 24. Mr. H. Auucocx.—A Criticism of the Majority Report of the Royal Commission on Decimal Coinage. Discussion, Mr. L. Surry Gorpon.—Agriculture as a Business. Suggestions as to the possibility of reconciling the psycho- logical and economic demands of agriculture with modern conditions by treating it as an industry to be organised upon a scientific basis. Mr. J. Lassen.—Danish Credit Corporations. Details concerning a system of co-operative borrowing of money on first-class mortgage security. The interest of the system lies in the fact that whereas all financing is usually performed through the medium of Lenders (bankers, trust companies, &c.), the scheme under review is directly reversed and relates to a ‘ Corporation of Borrowers.’ Discussion, introduced by Mr. C. R. Fay. Wednesday, August 25. Presidential Address by Dr. J. H. Cuapnam, C.B.E. (See p. 114.) Mr. J. O. CureTHam.—The present Supply of Coal and its effects on the Shipping Interests of Cardiff. Mr. R. F. Apats.—The Conduct of the Mining Industry. An examination of some of its economic and psychological aspects, with regard to the bearing on the socialisation of ownership and control. Discussion. Thursday, August 26. Mr. A. H. Grsson.—Credit : Inflation and Prices. A short review of the early beginnings of bank credit, its growth and elasticity in modern times, its relation to commodity prices; and the abuse of bank credit during the recent war. a ‘SECTIONAL TRANSACTIONS.—F, G. 363 8. Mr. A. J. Beamtse.—Deflation and the National Balance Sheet. A consideration of the alternatives before the Chancellor of the Exchequer. Discussion. 9. Mr. R. Trovron.—The Liquidation of International Debts. The fact that it was advantageous during the war for some countries to furnish mainly finance and others mainly men is not a reason for making the latter pay a tribute to the former. Discussion. Friday, August 27. 10. Communications from Research Committees of Section F. —Sir E. Brasrooxr, C.B. 11. Mrs. Woorron.—The Future of Earning. An examination of the principles on which payment for labour is now based and their probable future development ; with special reference to the relations of wages and prices and the influence of Government expenditure (by way of subsidies, &c.) on real income. Discussion, introduced by Prof. W. J. Roprrrs. SECTION G.—ENGINEERING. (For references to the publication elsewhere of communications entered in the following list of transactions, see p. 381.) Tuesday, August 24. 1. Presidential Address by Prof. C. F. Jenkin, C.B.E. (See p. 125.) 2. Prof. F. C. Lea.—Testing Materials al High Tempera- tures. 3. Col. R. E. Crompron, C.B.—The Cutting Edges of Tools. Excursion. In the afternoon a visit took place to the Bute Docks of the Cardiff Railway Co. Wednesday, August 25. 4. Mr. S. F. Evet.—Farm Tractors—Regarded from the Viewpoint of the User and Potential User. The writer traces the earliest appearances of the British farm tractor, explains its failure to earn the encouragement it deserved, and relates his experience of excellent work, to-day, from a ten-year-old machine built by pioneers of twenty years ago. He explains his preference, at present, for a certain type of machine, touches upon the psychological effect of the use of the tractor on the labour question, and then discusses the various main classifications of tractors 364 5. SECTIONAL TRANSACTIONS.—G. now in common use. Giving reasons for the greater success of one generic type, he confesses his inability to name any one machine which will do all sorts of work equally efficiently, mentions the poor quality of knowledge often possessed by those who actually operate tractors, but proceeds to encourage designers and manufacturers to give us better and better tractors, especially of better material, despite the temptation to turn out less serviceable machines at low prices. Road- haulage is a phase of tractor-work he asks designers to bear in mind, but he admits that ‘one machine for one job’ is a principle that designers and users may have, for some years, to respect. Tracing the history of the British industry, he sympathises with tractor-manutacturers in the past, he holds out hope of a fine future, if they will strive to give the farmer the best machines, in design, material, and workman- ship alike. He expresses his belief in the future of the tractor industry. Mr. H. R. Ricarpo.—A High-speed Internal-combustion Engine for Research. 6. Prof. W. H. Warxinson.—A Dynamical Method of Rais- ing Gases to High Temperatures. 7. Dr. C. Batuo.—The Partition of the Load in Riveted 8. 9. 11. Joints. Hecursion. In the afternoon a visit took place to the Melingriffith Tinplate Works. Thursday, August 26. Prof. J. T. Macerecor-Morris.—A Portable, Direct- reading Anemometer for Measuring Ventilation in Coal- mines. Mr. H. T. Tizarp and Mr. D. R. Pys.—Specific Heat and Dissociation in Internal-combustion Engines. Sir J. B. Henperson and Prof. H. R. Hasst.—The Indicator Diagram of a Gun. Prof. A. L. Meuuansy and Mr. W. Kerr.—Steam Action in Simple Nozzles. A Short Study of the Variants in Nozzle Expansion. This paper gives an exposition of a simple method of dealing with the latter in ‘straight’ nozzle expansion. It is intended as an introduction to a more detailed considera- tion, from the experimental point of view, of the same problems. The general methods of investigating steam flow are analysed, and it is shown that the somewhat neglected search-tube experiments are the most promising. The paucity of information regarding internal effects of steam expansion is noticed, and it is contended that the ordinary experiments on steam flow cannot give much further informa- tion upon interior happenings. A series of equations are derived from which the pressure ratio curve along a nozzle can be calculated, and experimental evidence is brought forward to show that the underlying theory is, at least, SECTIONAL TRANSACTIONS.—-G, H. 365 approximately correct. Arising from a desire to study jet conditions, the necessity of dealing with any type of expansion is postulated, and some discussion is given on the general influences of certain arbitrary laws of expansion on throat and flow conditions, Excursion. In the afternoon a visit took place to the Dowlais (Cardiff) works of Messrs. Guest, Keen & Nettlefolds, Ltd., at East Moors. Friday, August 27. 12. Prof. W. Cramp.—The Pneumatic Conveying of Materials. 13. Wing-Commander T. R. Cavu-Browne-Cave.—Airships for Slow-speed Heavy Transport and their Application to Civil Engineering. The use of airships as a means of transporting considerable loads over impassable country is developed from the opera- tions actually carried out up to the present. The application to Civil Engineering, Surveying, and Transport is discussed, and a review is made of the uses of airships for purposes other than those of the Mail and First-class Passenger Services, which have been fully dealt with by Air Commodore Maitland before the Royal Society of Arts. 14. Prof. G. W. O. Howrt.—The Efficiency of Transmitting Aérials and the Power required for long-distance Radio- Telegraphy. 15. Dr. J. S. Owens.—The Removal of Reefs in the Rio Guadiana. . This paper describes the removal by drilling and blasting of about 11,000 tons of rock reefs from the bed of the Rio Guadiana at Pomaron, the port of the San Domingos Mines. There is at this point a rise of tide of 11 ft. springs, maximum normal current up to about three knots, and a maximum depth over the reefs of 30 ft. Drilling was done from a floating drill barge using a 5-in. steam drill. Charging was done without divers and by means of specially prepared ‘sausages’ of dynamite dropped through a pipe and fired electrically in groups of about eight holes. Excursion. In the afternoon a visit took place to the surface plant of the Great Western Colliery Co., near Pontypridd, including large electric winder. SECTION H.—ANTHROPOLOGY. (For references to the publication elsewhere of communications entered in the following list of transactions, see p. 381.) Tuesday, August 24. 1. Presidential Address, by Prof. Karn Parson, F.R.S. (See p. 135.) 366 SECTIONAL TRANSACTIONS.—H. 2. Prof. H. J. Fururzt.—The Welsh People: Physical Types. Nine distinct physical types are found in Wales. Speaking generally the Welsh show more longheadedness, more dark pigment, and shorter statures than the English, but both are complex minglings of different breeds which in some cases can be correlated with migrations of prehistoric and historic times. 3. Miss M. L. Tiupestny.—Preliminary Notes on the Bur- mese skull. 4. Prof. F. G. Parsons.—The Modern Londoner and the Long Barrow Man. Afternoon. 5. Dr. Tuomas Asusy.—The Roman Site at Caerwent. 6. Mr. WitiovcHsy GarpNer.—Roman Site at Abergele. (See p. 262.) Wednesday, August 25. 7. Dr. W. H. RB. Rivers, F.R.S.—The Statues of Easter Island. In San Cristoval stone images represent the dead chief buried in the pyra- midal structures with which the images are associated. It is suggested that the statues of Easter Island represent a hypertrophy of one element of a similar association. 8. Captain L. W. G. Matcoum.—The Anthropogeography of the Cameroons, W. Africa. 9. Prof. E. H. L. Schwarz.—The Ovambo. 10. Signor Bacgnani.—Recent Archeological Discoveries in Rome. 11. Dr. T. Asusy.—Further Observations on the Roman Roads of Central and Southern Italy. The roads now described are the Via Valeria, and its prolongation the Via Claudia Valeria, which, with the Via Tiburtina, formed a continuous highway from Rome to the Adriatic, and the Via Latina. An attempt to discover the course of the Via Herculia from Venusia to Potentia was unsuccessful. One of the finest stretches of Roman pavement in Italy was discovered on the Via Cassia, which leads north from Rome through Etruria. 12. Prof. A. M. Woopwarp.—Note on Hacavations on a Hill Fort at Ilkley. Afternoon. Excursion to Caerwent. 4 a SECTIONAL TRANSACTIONS,—H, 367 Thursday, August 26. 13. Mr. L. H. Dupiry Buxton.—The Physical Anthropology of Ancient Greece and Greek Lands. The present essay is a continuation of a report rendered to the British Association at Bournemouth in 1919, on the ethnology of Cyprus, In classical times a clear distinction was made between ‘ Greeks’ and ‘ Bar- barians,’ and this distinction was believed to have a physical basis. Modern anthropologists are generally in agreement that at least two races are repre- sented in Greek lands, ‘Mediterranean’ and ‘Alpine.’ The aboriginal popula- tion remains at present uncertain, and in the absence of early material it became necessary to reverse the time process and to study the ancient popula- tion in the light of the modern. In order to make the matter clearer, the material has been divided into classes. First, head form is considered ; secondly, facial form; and thirdly, stature; a fourth class, pigmentation, has been added for the living. Evidence which can be treated statistically is available from Albania, Leukas, Messenia (Meligala), Peloponnese (Mani), Crete, Lycia, and Cyprus. The mean Cephalic Index varies from 79°20 in Crete to 87°51 among the Bektash of Lycia. None of the measurements are in agreement with the pure Mediterranean type as represented, for instance, in Corsica. Among the people who claim to be Greeks we have three classes—the Cretans, Maniotes, and Lycians have a cephalic index under 81, the Messenians and Cypriots a cephalic of 82, and the Leukadians and Albanians an index over 84, This classification does not appear to be of any real significance when we come to examine the standard deviations, as these are sufficiently great to suggest considerable admixture, especially in Lycia. Cranial~ evidence, such as it is, confirms this theory. The ancient crania which have survived form too small a series for statistical treatment. It appears as a general rule that the modern Greeks are slightly more brachycephalic than the ancient inhabitants of the same places—possibly sufficient correction has not been made for the difference between crania and living heads. From such scanty evidence as we have it appears that there is a general closer approximation between the earliest cranial indices and the modern ones than between either of the former and those of intermediate date. In Crete it would appear as though there was an immigration or an extension of the longheads in early times, who were later supplanted by a mixed round- and long-headed population. The following tentative conclusions have been drawn: First, the cranial indices of the Greeks exhibit great variety, sufficient to suggest ethnic admix- ture. Secondly, this admixture has not been evenly distributed, and local and distinct sub-races have been formed, so distinct that where crania over a long period have been obtained the cephalic index of one modern village more closely resembles that of their Bronze Age predecessors than that of a neighbour- ing area. As a corollary to this, any sweeping statements about the cephalic index of a modern administrative area, based on measurements made on sixty individuals, as has been done by Clon Stephanos, is unjustifiable. Thirdly, the mixture of race is early, possibly Neolithic in Leukas, certainly Bronze Age {or before) in Cyprus or Crete. The living stature is available, in large numbers, from Crete and Cyprus only, and in both cases the stature is practically identical. Three other small Series are available, all of which fall into a single shorter group—Leukas, Mount Parnon, and Lycian gypsies. The modern stature appears to be slightly greater than the ancient. The conditions, whatever they may be, which make for heterogeneity in cephalic index, appear also to make for a similar condition in stature. The small numbers represented, combined with the large degree of variation, suggest that great caution is needed in ascribing high or low stature to any race in our area. Considerable evidence has been brought forward to suggest that the Upper Facial Index is unreliable. If we accept it provisionally we find that it is a factor which, while agreeing to a large extent in showing the same degree of ‘ethnic stability’ as the cephalic index, in some cases shows wide divergencies; for instance, the cephalic index of the Cretans is most allied to 368 SECTIONAL TRANSACTIONS.—H. that of the modern Egyptians, whereas the index of Cyprus is the upper facial index which most closely approximates to that of the modern Egyptian. The standard deviations again suggest that there may be a mixture of race. In dealing with pigmentation there are two points of special importance. First, in Albania and Cyprus about one man in ten has blue eyes, and even in dark Crete one man in twenty; and secondly, there is evidence to show that pigmentation distinguishes the Western Alpines from their Hastern congeners the Armenoids. Pigmentation does not appear to bear a definite correlation to cephalic index. Summing up the evidence, we may say that at both boundaries of the Greek world there are two racial types of comparative homogeneity, and that those intermediate peoples who present local divergencies are very variable. As far as our present evidence goes, the division into numerous local types would appear to serve no useful purpose. We have not at present sufficient information to discuss the physical anthropology of Greece proper; such as we have would appear to justify the assertion that the numerous small communities of the ancient Mediterranean differed physically; that is to say, that there was a physical background to the struggles between Amathus and Salamis, Athens and Sparta. To suppose that it is possible to establish a Greek type and to distinguish. between Hellene and Barbarian does not appear justifiable. It has been suggested that the Nordic race has contributed to the popula- tion of Greek lands, but the presence of fair Alpines would account for the blue-eyed people of ancient Greece. In conclusion, then, while admitting the presence of numerous minor differ- ences sufficiently great to make it necessary to know the exact provenance of any anthropological data we may wish to examine, it would not seem possible at present to assign any definite racial position to the Greeks, but rather to class them as representing a combination, probably early in date, of Alpines and Mediterranean stocks, both of which are found sporadically in a compara- tively unmixed state in some parts of the Greek world. 14. Mr. 5S. C. Casson.—Ezacavations of the British School at Athens at Mycenae, 1920. In the area known as the Grave Circle on the Acropolis traces of early Bronze Age and Neolithic cultures were discovered. It seems certain that there was a continuous mainland civilisation stretching back to the beginning of the second millennium z.c. It has been possible to classify chronologically the works of the different generations of dynasts, and it seems that all the greater and’ more impressive monuments of Mycenae belong to the latest phase of Mycenaean culture. 15. Mr. J. Wurraxer.—Ezcavations at Motya, N.-W. Sicily. 16. Mr. P. E. Newserry.—Some early connections between Egypt, Syria, and Babylonia. Afternoon. 17. Prof. W. M. Furnpers Perriz, F.R.S.—Recent Work in Egypt. 18. Mr. BR. Campsett THompson.—The Earliest Inhabitants of Babylonia. Friday, August 27. 19. Prof. H. J. Freure.—The Scheme of the Welsh Depart- ment of the Board of Education for the collection of Rural Lore through the agency of Schools. 20. Mr. H. Kipner.—Round Barrows in the New Forest that do not conform to either of the three generally recognised types. aes SECTIONAL TRANSACTIONS.—H, I. 369 21. Mr. G. A. Garrirt.—Rock Sculptures from Eyam Moor Stone Circle, Derbyshire. 22. Mr. D. MacRitcum.—Greenland in Europe. Afternoon. 23. Dr. Lioyvp Wiu1aMs.—Welsh Traditional Music. 24. Dr. H. Watrorp Daviss.—Huphony and Folk Music. SECTION I.—PHYSIOLOGY. (For references to the publication elsewhere of communications entered in the following list of transactions, see p. 382.) Tuesday, August 24. 1. Presidential Address by Mr. J. Barcrorr, C.B.E., F.R.S. (See p. 152.) Joint Meeting with Subsection I. 2. Dr. C. S. Myers, F.R.S.—The Independence of Psychology. 3. Miss May Surry and Dr. W. McDovucatu, F.R.S.—The Mental Effects of Alcohol and other Drugs. Afternoon. 4. Dr. W. H.R. Rivers, F.R.S.—An Independent Section of Psychology (Discussion). Wednesday, August 25. 5. Visit to the New Laboratory of Physiology, Newport Road. 6. Dr. T. Lewis, F.R.S.—Auricular Flutter 7. Prof. A. D. Water, F.R.S.—Plant Electricity. 8. Prof. A. D. Watrer, F.R.S.—Emotive Response of the Human Subject (Lantern Demonstration). Thursday, August 26. 9. Dr. T. Lewis, F.R.S.—The Relation of Physiology to Medicine. 10. Prof. P. T. Herrinc.—The Effect of Pregnancy on the Organs of the White Rat. 11. Miss E. Bepate (in collaboration with others).—Report on Caloric Value of the Ordinary School Meals and on the Energy Output of the School Day for Ages 10 to 18 Years. 12. Miss Hips Watxer, Prof. A. R. Lina, and Mr. E. A. Coorrr.—On the Estimation of Sugar in Blood (pre- . liminary communication), 1920 BB 370 SECTIONAL TRANSACTIONS.—I. The authors have investigated methods of estimating sugar in blood, and consider that of Maclean to be convenient and accurate. They have improved its technique somewhat. As regards the nature of the cupric-reducing sub- stance present in normal blood, they show that it is neither creatinine nor uric acid; that it is insoluble in ether; that its reducing power is destroyed by boiling with ammonia; that it is completely dialysable, and when dialysed against aqueous glucose solutions, equilibrium is adjusted as it should be with glucose; it forms a crystalline osazone morphologically similar to glucosazone. The authors conclude, therefore, that the reducing substance is glucose. 13. Dr. F. W. Eprince Green.—The Prevention of Myopia. The direct exciting cause of myopia appears to be increase of intra-ocular tension through back pressure on the eye, therefore lengthening its antero- posterior diameter. There is no satisfactory evidence that the use of the eyes for near work either increases or causes myopia. In the prevention of myopia any cause which will increase the intra-ocular tension by obstructing the outflow should be avoided. All exercises in children which involve strain with the eyes pointing downwards should be avoided. A typical example of this is the exercise in which a child moves itself up and down from the floor with the eyes pointing downwards. Physical training is of great importance, and it will be noticed that the ordinary forms of exercise—cricket, football, golf, &c.—do not cause myopia, whereas lifting heavy weights, dumbbells, wrestling, boxing, or riding a bicycle uphill in a stooping position, do. It is particularly in those who have sedentary occupations, and who are not in a fit physical condition, and have an hereditary tendency to myopia, that these forms of exercise should be avoided. Exercises which after inquiry are found to cause a feeling of pain or tension in the eyes or distension of the veins of the neck should be strictly forbidden to myopes. Reading in a recumbent or stooping position with the eyes pointing downwards is not advisable. Afternoon. 14. Visit to Cardiff City Mental Hospital at Whitchurch. Dr. R. V. Sranrorp demonstrated various Biochemical Methods. Friday, August 27. 15. Prof. A. D. Wauuer, F.R.S.—The Energy of the Human Machine as Measured by the Output of Carbon Dioxide. 16. Demonstration by Prof. J. B. Haycrarr.—d New Electrokymograph. 17. Joint Discussion with Section K on Biochemistry and Systematic Relationship. (See p. 374.) SUBSECTION I.—PSYCHOLOGY. (For references to the publication elsewhere of communications entered in the following list of transactions, see p. 382.) Tuesday, August 24. Joint Meeting with Section I. (See p. 369.) Wednesday, August 25. 1. Miss L. C. Frrpes.—Word-blindness in the Mentally Defective, SECTIONAL TRANSACTIONS.——I, K. 871 Miss V. Hazuitt.—Conditions of Learning compared in Man and Rats. Prof. C. Luoyp Morean, F.R.S.—The Territory Instinct in Birds. Mr. F. B. Kirxman.—The Experimental Study of Animals in the Wild State. Afternoon. Dr. E. Pripraux.—A Psychologist’s Attitude towards Telepathy. Prof. AcNes Roaers.—Mental Tests in American Univer- sities. Thursday, August 26. Joint Meeting with Section L. (See p. 378.) Afternoon. Dr. W. H. R. Rivers, F.R.S.—The Complex and the Sentiment. Discussion, opened by Miss Saxsy. Mr. F. C. Barrierr.—The Function of Images. Friday, August 27. Mr. F. Warts.—Some Problems of Vocational Selection. Mr. 8S. Wyarr.—The Psychology of Industrial Life: Observations on Operatives in the Cotton Industry. Prof. EK. L. Connis.—The Psychology of Industrial Con- valescence. Afternoon. Mr. Henry Binns.—Psychological Skill in the Wool Industry. Prof. F. 8. Lzz.—Some Phenomena of Industrial Fatigue. Dr. G. H. Mirzs.—Aims and Work of a National Institute of Applied Psychology. Dr. H. M. Vrernon.—The Influence of Adaptation after Altered Hours of Work. SECTION K.—BOTANY. For references to the publication elsewhere of communications entered in 5 the following list of transactions, see p. 382.) Tuesday, August 24. Presidential Address by Miss E. R. Saunpgrs. (See p. 169.) BB2 372 10. 11. SECTIONAL TRANSACTIONS.—-K. Professor Luoyp Wriuu1ams.—Alternation of Generations in the Laminariacee. Mrs. Evranor M. Rew.—The History of the West Euro- pean Pliocene Flora as Deciphered by the Study of Fossil Seeds. Afternoon. Prof. R. Cuopat.—Some Aspects of Plant Ecology and Biology in Paraguay. Prof. F. J. Lewis and Miss Gwynnetu M. Torrie. On the Phenomena attending Seasonal Conversion of Reserve Food Materials in the Leaves of Picea canadensis. Miss Gwynnetu M. Turttr.—On the Nature of Reserve Food Materials in the Tissues of some Plants of Northern Alberta. Wednesday, August 25. Joint Discussion with Sections C and D on Mendelism and Palaontology: The Factorial Interpretation of Gradual Changes, especially when New Characters appear late in the Individual Life-cycle. (See programme of Section C, p. 354.) Dr. E. A. Newent Arper.—The Leaves of the Irids and the Phyllode Theory. Afternoon. Dr. Harorp Wacer. Geotropism of Foliage Leaves; Geotropie and Nastic Growth; Localisation and Differentiation of Geotropic Stimulus. Are Leaves dia-geotropic ? Prof. J. Smaun and Miss W. Rea.—Further Evidence for the Differentiation in Hydrion Concentration in stem and root as the explanation of Positive and Negative Geotropism, with evidence for Carbon-Dioxide Balance as the cause of that Differentiation. Miss K. B. Buacksurn.—Anomalies in Mucrospore Formation in ‘ Rosa’ and its possible connection with Hypbridity in the Genus, including a description of normal. meiosis in three species for comparison with abnormal features found in ten forms, including two hybrids. Excursion. A short Botanical Expedition took place to visit local plants of considerable interest. ee SECTIONAL TRANSACTIONS.—K. 373 Thursday, August 26. Joint Discussion with Section M on Soil and Plant Survey Work. Botanical part of the discussion centred round : (i.) Types of grassland in view of importance in Wales and in general in agriculture—the possibility of recognising a number of types in different parts of the country. Ee (ii.) Possibility of fixing on Some standard symbols or colours for ecological mapping. (ili.) Relation of ecological data to geological data. (iv.) Study and representation of arable. 12. Mr. G. W. Rosinson.—Soil Types of North Wales. It is suggested that while uniformity in sampling and analytical methods should be secured, the classification of soils must depend on the local conditions. In extreme humid conditions it would appear that differences due to geological factors tend to be obliterated. Large numbers of soil samples should be collected and the types should be worked out from actual observations, correlation with geology may follow afterwards. The soil survey gives information as to one of the factors affecting plant growth and, ultimately, agricul- ture in a particular area. The survey in its widest sense should take cognisance of all the other factors, including climate and soil-water conditions. The vegetation survey gives the results of the operation of all these factors. 13. Mr. E. A. Fisuer.—Soil Acidity. 14, Prof. R. G. SrarLepon.—Surveys of Grassland Districts. Re (i.) A method of obtaining quantitative data; ~sub- division of grassland; Fescue Agrostis pastures in detail. Effect of grazing animals. Re (ii.) Colour scheme must allow for transitions; sub- types by ink symbols on a ground colour. Re (iv.) Use of weed flora in representation of arable. Importance of primary survey. 15. Miss W. H. Wortnam.—The Vegetation of Anglesey and N. Carnarvonshire, with special reference to the Grass- lands. Until about 700 years ago the vegetation of Anglesey and N. Carnarvonshire comprised : (1) an area of moorland stretching up from the 1000-1700 contours over the Carnarvonshire mountains, interrupted only by the associations of the summits, rock-ledges and screes ; (2) A zone of woodland extending from the edge of the moorland to sea-level, interrupted by marshes and by lowland moors. The plant formations are closely related to the geological structure of the district. The greater part of the uncultivated area is now grassland and may be summarised thus: (i) the sub-alpine grassland which has been derived from upland moor. (ii) The siliceous, schistose, and cal- careous grasslands which have been derived from the corre- sponding woodlands. (iii) Molinia grassland formed (a) as a product of the degeneration of woodland, or (b) as a primary association developed on wet rocks ; (3) Grassland, siliceous, schistose, or calcareous, according to the nature of the soil, has also been formed by the degeneration of lowland moor, the draining of the marshes, the colonisation of screes, and the colonisation of sand-dunes 374 16. 17. SECTIONAL TRANSACTIONS.—K. Discussion.—Sir A. D. Hatt, K.C.B., F.R.S., Dr. E. J, Russevu, F.R.S., Mr. C. G. T. Morison, Mr. T. J. JENKIN, Mr. C. T. Gimmincuam, Mr. R. Auun RoBerts, Dr. EK. N. Tuomas, Prof. Luoyp Wriuuiams, Mr. T. W. FaGan. In the Section Room. Mr. D. Parron.—The Vegetation of Beinn Laoigh situated on the West of the Breadalbane Mountains. Its Con- figuration, Geological Formation, Climatic Conditions, &c., and the Relation of these to the Conditions of Plant Life, with special reference to the Associations. Hacursion. Botanical expedition to Mynydd y Glew and Wenyoe, vid Cow- bridge. Lunch was provided by the kind invitation of Mr. and Mrs. T. Mansel Franklen, and tea at Duffryn by Mr. and Miss Cory. 18. 19. 20. 21. Friday, August 27. Prof. F. J. Lewis.—Distribution of Vegetation types in the Hastern Canadian Rocky Mountains (Lantern Demonstration). Mr. P. E. Marvingau.—Records of Growth of Pit Mound Plantations. Joint Discussion with Sections I and B on Biochemistry and Systematic Relationship, opened by The Hon. Mrs. Onstow.—Introductory paper on Buo- chemistry and systematic relationship in the plant kingdom. Brief consideration of systematic relationship.—Bio- chemical aspect of the plant.—Possibility of expression of reproductive and vegetative characters in chemical terms.— Lines of plant metabolism.—Aromatics.—Catechol and pyro- gallol plants.—Oxidase and peroxidase plants. Suggestions as to connection with relationships of other substances—e.g., anthocyan pigments, flavones, &c. Dr. F. F. Buackman, F.R.S.—Photosynthesis and carbo- hydrate metabolism from the point of view of systematic relationship in plants. The pigments of chloroplasts: their uniformity in phanerogams and their diversity in certain phyla of alge. The primary products of photo-reduction of CO,: the balance of hexoses and pentoses in different groups : pentoses as the basis of the succulent habit. Diversity of condensation-products: saccharose, starch, and inulin, their occurrence in relation to species and families. Riechert’s work on the individuality of the starch grains of every species of plant: its bearing on the chemical speci- ficity of protoplasms. ee a ee, Se a ee tal NE hl ne eee See ste ™ Dh dee pes ; SECTIONAL TRANSACTIONS.—K, L. 375 22. Prof. G. H. Nurrauy, F.R.S. — Precipitive Reactions as a means of determining Systematic Relationships in Animals and Plants. 23. Mr. J. Barcrort, F.R.S.—Correlation of properties of the oxygen-carrying power of blood (essentially the proper- ties of hemoglobin) with the functions and habits of the animal in question rather than with its phylogeny. Afternoon. 24. Prof. C. J. CHampBeruain.—Semi-popular lecture on The Origin and Relationships of the Cycads. 25. Mr. Kiyapon Warp.—On the Distribution of Floras in S.-H. Asia as affected by the Burma-Yunnan Ranges. 26. Sir J.C. Bosz, F.R.S.—Plant Autographs and their reve- lation, with demonstration of growth by means of the Magnetic Crescograph. Exhibition. There was an exhibition during the Meeting of microscope preparations, drawings, specimens, maps, &c. (many illustrative of the papers). SECTION L.—EDUCATION. (For references to the publication elsewhere of communications entered in the following list of transactions, see p. 383.) Tuesday, August 24. 1. Presidential Address by Sir Roperr Buam. (See p. 191.) 2. Report of the Committee upon Training in Citizenship. (See p. 281.) Speakers: Bishop Weruipon, Mr. J. Cuarke, Mr. A. Parrerson. Afternoon. 3. Mr. Spurtey Hey.—The Supply of Teachers. There is a serious shortage in the supply of teachers. The actual supply is insufficient to repair wastage, makes little contribution towards increase in quality of staff, and makes no increase whatever towards reduction of classes and other necessary reforms, or towards additional require- ments arising under the Education Act, 1918. Boards of Education policy has led to a decrease in supply; some L.E.A.’s have done nothing, whilst most L.E.A.’s have failed to supply their own wastage; the teaching profession has for some years been often indifferent, sometimes hostile, to the creation of an adequate supply. The Board of Education should provide adequate money and should penalise default- ing L.E.A.’s. L.E.A.’s must provide good scales of salaries and better school conditions, and must utilise the wider avenues now allowed by the Board of Education. Teachers 376 SECTIONAL TRANSACTIONS.—-L. should actively co-operate in creating an adequate supply. Rural areas must be more thoroughly tapped for young recruits, educated manhood and womanhood for adult recruits. Wednesday, August 25. (4-7). Papers on The Relation of Schools to Life, as follow- Ingest 4. Mr. A. Linecar. Schools should induce capacity for life as well as, or before inducing, ability to earn a livelihood. A general governing principle guiding all the school work is wanted, as ‘Induce into pupils the power of concentration of mind.’ Then multiplicity of subjects disappears; we have instead various postures of one endeavour. The broader the curri- culum the broader the culture. We shall find we can vary our postures so as to cultivate capacity to appreciate art, literature, beauty, nature, nobility; we shall no longer find ourselves struggling to attain sectional high efficiency. We shall give power to be happy, the greatest gift; we shall give possibility of broad, tolerant, healthy and full mental life: we shall find that unusual efficiency has come, unsought, so that while giving a splendid chance of real life we have also provided an added probability of livelihood. 5. Mr. J. M. McTavisa. (1) Primary function of schools to assist in cultivating such practical emotional and intellectual habits, systemati- cally organised as will fit man to his social and physical world. (2) Necessity of re-interpreting in terms of man’s widening social relations individualistic conceptions of edu- cation which hinder us from understanding. the importance of their social function. (3) Education as being the develop- ment of the physical and mental capacity too limited. It dissociates education from social change. (4) Each historic epoch carries with it corresponding changes in educational motives and methods. (5) During periods of social stability this creates no problems, but man’s social world is to-day in a condition of rapid flux. (6) The world’s problems due to conscious social conduct being primarily determined by sentiments which determine the behaviour of the conscious stream and their influence upon consciousness may be regarded as the psychological analogue of the conception of force in physics. (7) The disintegrating sentiments in civili- sation are egoism, patriotism, and class sentiment. (8) The need for cultivating a human sentiment powerful enough to hold these in check. (9) The relation of the above con- siderations to secondary education. (10) Schools most closely related to life through adolescent education. 6. Mr. RB. O. Bray. Paper concerned with industrial aspect of life. Need for industry to regard the entrants as persons in training. Ten- dency of industry to regard them as adults. No adequate provision made for trade teaching, for physical welfare, or for general training. Figures justifying statement. Work- shop training neglected both-by employers’ associations and trade unions. Tendency to regard the schools as offering a substitute for training in workshop. The workshop, the stronger influence, undermines the training in the schools. The most urgent educational problem lies not inside the Pie: 9. SECTIONAL TRANSACTIONS.—L. 377 schools. but in industrial life outside. The solution must be found by industry, trade unions, and employers, regarding the juvenile worker as a person in training. The double duty of the schools: first to educate industry itself by securing a change of attitude towards its method of regarding the juvenile worker. Secondly to assist industry in the selection and training of its entrants. The first the most important and the most neglected of the tasks. The schools must pre- pare industry for the child before it can prepare the child for industry. Miss StRUDWICE. General Discussion, Joint Meeting with Section E. (See p. 361.) Prof. J. L. Myres.—The place of Geography in a Reformed Classical Course. Recent decisions about ‘compulsory Greek’ compel drastic revision of classical teaching. With language courses restricted and postponed, the aim must be earlier acquaint- ance with ancient conduct and thought, through closer co- ordination between history, literature, and geography. The Mediterranean region being exceptionally suited to supplement, by contrast, Homeland notions of geography, and being also the physical cradle of those ancient cultures, Hebrew and Greco-Roman, which have most influenced our own: reformed ‘classical’ education would begin by illustrating, through ancient narrative and description, in translations, man’s behaviour under these conditions, both normally and in great crises; and his solutions of social and moral problems in ancient times compared with ours. Later, these episodes would be linked, chronologically and topo- graphicaily, to illustrate historical growth and_ interaction between local types. But study of ‘special periods’ would be reserved till these outlines were familiar, and ancient languages until required for appreciation of literature. Afternoon. Dr. Vincent Naser.—The International Intellectual Relations. Wealth of a nation, a function of its directing energies. All students to organise locally, creating committees at each University representing both undergraduates and _post- graduates, and having complete modern office equipment at their disposition. These committees to take the initiative of establishing local bureaux of information under the super- vision of University authorities, and acting as local branches to central State-authorised bureau of all the nation’s Univer- sities. Local committees to elect National Council of Students. Necessity of caring for undergraduates travelling abroad by established bureaux of information, and creating facilities for introduction to families, etc. Tendency at modern Universities to specialise in certain post-graduate specialities to be encouraged to avoid overlapping. Idea of World’s University to be realised locally by the inter- nationalisation of post-graduate education with lectures in English and French being prepared by the teaching of Eng- lish and French in all schools. Introduction of official students, international identity cards with photo of bearer 373 10. 11. 12. 13. 14. 15. 16. SECTIONAL TRANSACTIONS.—tL. affixed, etc. Railroad and shipping companies to provide special rates, after being shown the necessity for the keeping up of the standard of instruction and life generally of intellectual classes. Thursday, August 26. Joint Meeting with Subsection of Psychology. Prof. T. P. Nunn.—The Tendency towards Individual Education. Education must effect a modus vivendi between two prin- ciples : (i.) the principle of ‘mental discipline,’ and (ii.) the principle of spontaneity which requires the pupil to be his own educator. The second implies that the individual pupil, not the class, is the proper unit for instruction, and that he should be free to go his own way at his own speed. The former demands expert control of his studies and at least a minimum prescribed curriculum, The problem of reconciling the two principles in the case of young children is relatively simple, and has been solved (e.g.) by Dr. Montessori. For older pupils it seems to require (a) the reduction of formal class-teaching to a minimum, and (6) setting free a large part of the school week for ‘elective’ work under tutorial supervision. Cautious experiments in this direction are immediately practicable, and should be encouraged. Prof. G. H. Tsomson.—Do the Binet-Simon Tests measure General A bility ? Dr. C. W. Kimuins.—The Dreams of Children who are Physically Abnormal. General Discussion upon the above Papers. Afternoon. Report of Committee upon the Educational Value of Museums. (See p. 267.) Friday, August 27. Right Hon. H. A. L, Fisner.—The Universities m a National System of Education. Mr. Frank Furrcuser.—The Public Schools in a National System of Education. Miss H. M. Woprnovusse.—The Training Colleges in a National System of Education. Do we aim at requiring that all teachers, including all those teaching ages 2-11, shall be graduates? (Estimate of numbers.) Jf not, training colleges other than university departments ought still to exist: (i.) To take non-matri- culated students, (ii.) to take students who, even though qualified for matriculation, do not wish to take a full-length university course. From staff, from learning, and from social life, these students gain more in a college of their own than in a university. Most desirable that training colleges should be widened by amalgamating the training of teachers with other work. Z.g., physical training, arts, crafts, agri- culture, engineering, preparation for business or secretarial 17. SECTIONAL TRANSACTIONS.—L, M. 379 work, for social service, &c., &c. Question of connection with universities (absorption in universities being rejected). (a) Advantage to staff; (b) should improve some governing bodies. The university should not act as external examiner to the college. Services apart from official connection. Mr. J. C. Maxweut Garnert, C.B.E.—Higher Tech- nical Schools in a National System of Education. The paper included a description of his diagram of a national] system of education. The diagram illustrated cer- tain recommendations recently published by the Federal Council of Lancashire and Cheshire Teachers’ Associations. The diagram represented sixteen different types of education ; nine different types of school or college; a system of scholar- ships and maintenance allowances sufficient to secure that every kind of education is brought within the reach of all young people of sufficient educational promise; and the num- bers of young people who should be attending any particular type of school or receiving any particular type of education at any given age. As indicated by its title, the paper was especially concerned with the provision of the highest technological education in the national system of education represented in the diagram. A General Discussion followed. Afternoon. Excursion to Barry Summer School. SECTION M.—AGRICULTURE. (For references to the publication elsewhere of communications entered in the following list of transactions, see p. 383.) Tuesday, August 24. Presidential Address by Prof. F. Kursus, C.B.E., F.R.S., on Intensive Cultivation. (See p. 200.) Mr. H. V. Taytor (Ministry of Agriculture).—The Distri- bution of Wart Disease in Potatoes; (b) Some Results of the Ormskirk Potato Trials. Mr. F. J. Currrenpen.—EHzperimental Error in Potato Trials. Mr. T. Wurrenpap.—A Preliminary Repori on the Para- sitic Fungi of North Wales. Mr. C. L. Watton.—Agricultural Zoology of North Wales. Wednesday, August 25. Captain R. Wettweaton (Ministry of Agriculture).— Orchard Survey of West of England. Mr. R. G. Hartron.—f ruil Tree Stocks: Mr. §. P. Wiursurre.—Methods of Infection of Apple Trees by Nectria ditissima, Tul. 2 . 380 SECTIONAL TRANSACTIONS.—M. 9. Prof. T. WispertEy.—LHzperiments in Intensive Corn- growing. 10. Prof. A. Henry.—The Artificial Production of Vigorous Trees. Afternoon. Excursion to St. Fagans. Thursday, August 26. 11. Joint Discussion with Section K (see p. 373) on Plant and Soil Survey Work. Friday, August 27. 12. Mr. Georce S. Ropertson.—Result of Experiments with Rock Phosphates. 13. Captain H. J. Pace, M.B.E.—EHzperimenis on Green Manuring of Light Soils. 14, Mr. 8. Hoare Cotuins.—Sugar Content of Straw. 15. Mr. C. B. V. Marquanp.—The Varieties of Oats. REFERENCES TO PUBLICATION OF COMMUNICATIONS TO THE SECTIONS. AND OTHER REFERENCES SUPPLIED By AUTHORS. Under each section, the index-numbers correspond with those of the papers in the sectional programmes (pp. 351-380). References indicated by ‘cf.’ are to appropriate works quoted by the anthors of papers, not to the papers themselves. Srecrion A. 2. Cf. Bulletins Kodaikanal Observatory, 1913-18 ; also Observatory, Apr. 1920. 4. To be published in Proc. London Math. Soc. 6. To be published in Messenger of Mathematics ; cf. recent papers, ibid., on Pentaspherical Co-ordinates. 7. Cf. Phil. Mag., 39, p. 707, Dec. 1919 ; 40, p. 451, Apr. 1920; p. 611, May 1920. 9. Expected to he published in Phil. Mag., Nov. 1920. 10. Cf. J. H. Moore, ‘ Recent Spectrographic Observations of Noya Aquile III.,’ Asirorom. Soc. of Pacific, 32, p. 232. 11. Observutory, 43, No. 558, Nov. 192€. 14, To be publishedin Nature. 17. Cf. Proc. Roy. Soc.,95A ; Camb. Phil. Trans., Oct. 1919; also forthcoming Encyclopedia of Physics, ed. Sir R. T. Glazebrook (Macmillan), s.v. Terrestrial Mag- netism. 18. To be published in Proc. Roy. Soc. ; cf. Phil. Trans., 214A, p. 109 (1914) ; 215A, p. 79 (1915) ; 220A, p. 247 (1920) ; Proc. Roy. Soc., 95A, p. 58 (1918) ; Sctence Progress, Mar. 1920. Srcrion B. 2. Journ. Soc. Chem. Ind., Sept. 15, 1920. 8. Results to be published in 6th Rep. Advisory Committee on Atmospheric Pollution. t Section C. 2. See Handbook to Cardiff (B.A. Meeting, 1920); also Proc. Geol. Assoc., 31, p. 45 (1920). 8. Expected to be published in Mineralogical Magazine. REFERENCES TO PUBLICATIONS, ETO. 381 10. To be published (abbreviated) in Geol. Mag. 12. Cf. ‘The Arrangement of Atoms in Crystals,’ Phil. Mag., 40, Aug. 1920 ; * Crystal Structure,’ Royal Inst., May 28, 1920. Srorion D. 8, For summary of discussion, see Nature, 106, p. 30. 10. Nature, 105, p. 516. 11. Nature, 105, p. 197 16. Journ. Exp. Zool., 30, p. 1. Section E. 2. To be published in Yearbook Welsh Housing and Development Assoc., 1921. 3. Cf. Geog. Journ., 1919, p. 410. 8. Volume, The Sites of Imperial Cities, in preparation. 10. Cf. Fishery Investigations Reports (new series), III. Hydrography, 1; Hydro- graphy of the English Channel, pt. 1 (Start Point to Channel Is.), 1904-17; pt. 2 (Isle of Wight to Cape de la Hague), 1904-18 ; pt. 3 (Isle of Wight to Havre), 1904-18 ; pt. 4 (Newhaven to Caen), 1903-12 ; pt. 5 (Plymouth to Brest), 1907-11. 2. Hydro- graphical Observations at English Lightships, pt. 1 (Seven Stones Lightship). 3. Hydrography of the Atlantic Ocean, pt. 1 (Area centred on 50°N., 20° W.) 4. Hydro- graphy of the North Sea, pt. 1 (Section from R. Tyne towards Naze of Norway). 11. Cf. The Kalahari, by E. H. L. Schwarz (Blackwell, Oxford, and Miller, Cape Town), 1920. 12. Cf. Builder, 94, (1908, i.), pp. 37, 64, 89, 111, 121, 142, 153, 174, 184, 203, 234; Neue Jahrbiicher fiir das Klassische Altertum, 23 (1909), pp. 246-260; Public Works, 2, iii. (Jan. 15, 1904), pp. 193-201; also ‘ Livellazione degli Antichi Acquedotti Romani, memoria del Prof. V. Reina, degli Ing. G. Corbellini e G. Ducci,’ in-Memorie Soc. Ital. d. Scienze detta dei XL., series 3a, 20. Section F. 1. Waysand Means, Oct. 16, 1920, p. 62. 2. Better Business (Co-op. Ref. Library), Noy. 1920. Cf. Rural Reconstruction in Treland (P. 8. King & Son), Co-operation for Farmers (Williams & Norgate). 5. Cardiff Journal of Commerce, Aug. 26,1920; Colliery Guardian, Aug. 27, 1920. 7. Bankers’ Magazine, Oct. 1920. 9. Economic Journ., Dec. 1920. Section G. 2. Engineering, Aug. 27, 1920, p. 293. 3. Aug. 27, 1920, p- 292. 4. Farm Life, Sept. 4, 1920. 5. Engineering, Sept. 3, 10, 1920, pp. 325, 361. 6. As Aug. 27, 1920, p- 276. 7. rf Sept. 3, 1920, p. 314. 8. fs Aug. 27, 1920, p. 279; The Hlectrician, Aug. 27, 1920. 9. a Sept. 3, 1920, p. 325. d 11. Ss Sept. 3, 1920, p. 310. 12. # Sept. 3, 1920, p. 330. 13. Sept. 3, 1920, p. 381. 14, Radio Review, Aug., Sept., Nov. 1920. 15. The Engineer, Aug. 27, 1920, p. 201. Srotioy H. 2. Cf. Journ. Roy. Anthrop. Inst., 46 (1916), 48 (1918), 50 (1920). 3. Cf. (forthcoming) Biometrika, 13 (1921). 5. Cf. Arch@ologia, 57, pp. 295-316 (1901); 58, pp. 119-152 (1902), 391-406 Sees a 59, pp. 87-124 (1904), 289-310 (1905) ; 60, pp. 111-130 (1906), 451-464 (1907): 61, pp. 565-582 (1909) ; 62, pp. 1-20 (1910), 405-448 (1911) ; 63, pp. 487-452 (gis). 7. Expected to be published i in Folk Lore. 11. Cf. (forthcoming) R. Gardner, ‘ The Via Valeria,’ in Papers Brit. School a Rome, 10, and future articles by T. Ashby and R. Gardner, also (forthcoming) T. Ashby on an ancient Lucanian hill-fort in Journ. Roman Studies. 18. To be published in Biometrika; also forthcoming article in Nature. 382, SECTIONAL TRANSACTIONS. 14, To be published in Annual of the British School of Archaeology at Athens, XXIV. ; see also Times Literary Supplement, June 24, 1920 (A. J. B. Wace), and July 15, 1920 (Sir Arthur Evans). 15. Man, Dec. 1920. 17. Results to be published in Lahun IJ., Brit. Sch. in Egypt. 18. Cf. (forthcoming) Semitic Mythology (series, Mythology of all Races, Marshall Jones, Boston, U.S.A.) ; also ‘ The British Museum Excavations at Abu Shahrain,’ in Arch@ologia. 20. Proc. Hampshire Field Club and Archeological Soc., 1920. 21. To be published in Man. 22. Expected to be published (abbreviated) in Discovery. Cf. ‘The Lapps in Scotland.’ The Link, Sept. 1917 (Bellows, Gloucester) ; ‘ Kayaks of the North Sea.’ Scott. Gecg. Mag., Mar. 1912; ‘ The Kayak in North-Western Europe.’ Journ. Roy. Anthrop. Ins., 42, 1912 ; * The Abudeen Kayak and its Congeners.’ Proc. Soc. Antigq. Scot., 1912; ‘ Les Kayaks dans le Nord de l'Europe,’ Compte Rendu XIVe Session (Genéve, 1912) Cong. Internat. d’ Anthrop. et d’ Archéol. Préhist., 2, 1914; ‘ Der Kajak im nérdlichen Europa,’ Petermanns Mitt., 1911; ‘Notes on a Finnish Boat pre- served in Edinburgh,’ Proc. Soc. Antig. Scot., 1890; ‘The Testimony of Tradition ’ (Kegan Paul, 1890). 24, Cf. Musical Times, Oct. and Nov. 1920. Secrion I. 2. To be published in Discovery. 3. To be published in special reports, Medical Research Council. Cf. communi- cations to Brit. Assoc., 1913 and 1915, published as ‘ A Contribution to the Study of Fatigue,’ in Brit. Journ. Psycholugy, 8. 9. Brit. Med. Journ. 2, pp. 439-462 (1920). 10. Brit. Med. Journ., Dec. 11 (1920), p. 886. Sussecrion I (Psychology). 8. Cf. ‘ Instinctive Dispositions,’ Sctentia, Oct. 1920. 4. Cf. (forthcoming) The Intimate Life oj a Seagull (T. C. & E. C. Jack, 1921) ; paper to be published probably in Brit. Journ. Psychology. 6. To be published in Brit. Journ. Psychology. 10. To be published in Brit. Journ. Psychology, 11, pt. ii. (Jan., 1921). 11. Cf. forthcoming Reports of Industrial Fatigue Board. 12. To be published in Hngineering and Industrial Management. 13. Wool Record and Fextile World, Aug. 26 and Sept. 2, 1920; Cf. ‘ The Human Factor in the Judgment of Yarn and Cloth,’ to be published in Journ. Bradford Textile Soc. and Wool Record. 14, Cf. ‘Studies in Industrial Physiology: I. Comparison of an Eight-Hour Plant and a Ten-Hour Plant : Report by Josephine Goldmark and Mary D. Hopkins on an Investigation by P. S. Florence and Associates under the general direction of Frederic 8. Lee,’ Public Health Bulletin, No. 106, U.S. Public Health Service, Washington. 16. Report No. 6, Industrial Fatigue Research Board, 1920. Section K. 3. Cf. Paper to be published by Geological Soc. 4. Cf. R. Chodat and W. Vischer, ‘ Végétation du Paraguay,’ in Bull. Soc. Botan. Genéve (1916-20). 8. Abstract to be published in Journ. Indian Botany, and it is hoped that the full paper will appear in Annals of Botany. 10. Summary in New Phytologist, 19, p. 208 (1920) ; cf. ‘ A Theory of Geotropism,’ ibid. 19, p. 49 (1920). 11. Results to be published (with Dr. J. W. H. Harrison) in Annals of Botany. 12. Cf. ‘ A Survey of the Soils ana Agriculture of Shropshire,’ published by Salop County Council, 1913; ‘Studies on the Paleozoic Soils of N. Wales’ in Journ. Agric. Science, 8, 3; ‘ Further Studies on the Soils of N. Wales’ (in collaboration with O. F. Hill), 2bid., 9,3; Dr. Edward Greenly in Geol. Survey Memoir on Anglesey, pp- 877-881. 13. To be published in Journ. Agric. Science. Ce a Zz : REFERENCES TO PUBLICATIONS, ETC. 383 19. Cf. Communication to Brit. Assoc., Newcastle, 1916; also annual Reports Midland Reafforesting Assoc., 1905-19. 20. Cf. (forthcoming) Biochemical Journ. ; also ‘ Nature of the Peroxide naturally associated with certain direct oxidising Systems in Plants,’ in Biochemical Journ., 18, p. 1 (1919). 21. To be published in New Phytologist, Jan. 1921. 24. Cf. C. J. Chamberlain, The Living Cycads (Univ. of Chicago Press) ; Botanical Gazette, passim. Srerion L. 4, Education, Sept. 24, 1920. ; 5. Highway, Oct. and Noy., 1920; Education, Oct. 1, 1920. 6. Cf. R. O. Bray, Boy Labour and Apprenticeship (Constable). 7. Journ. of Education, Oct. 1920. 11. Cf. ‘ General versus Group Factors in Mental Activities,’ in Psychological Review, 1920. 14, Education, Sept. 3, 1920; Tie Times Educational Supp., Sept. 2, 1920. 15. Journ. of Education, Oct. 1920. 16. To be published in Education. Cf. Atheneum, July 1917. 17. Cf. An International System of Education (Manchester University Press). Srction M. 2. Journ. Ministry of Agriculture and Fisheries, Nov.—Dec. 1920. 5. Cf. (for Mid-Wales). ‘The Liver Rot of Sheep, and Bionomics of Limnza truncatula in the Aberystwyth Area,’ and ‘ Some Results of a Survey of the Agricul- tural Zoology of the Aberystwyth Area’ (both in) Parasitology, 10, 2 (1917) ; ‘Farm Insects Observed in the Aberystwyth Area, 1913-16,’ and ‘ A Note on Agricultural Decology in Mid-Wales,’ in Annals of Applied Biology, 4, 1 and 2 (1917). 7. Journ. of Pomology, 5, Nov. 1920; Gardeners’ Chronicle, Oct. 16, 1920; cf. Journ. R.H.S., 42, p. 261 (1917), 44, p. 89 (1919), 45, pp. 267, 269 (1920) ; Bulletin, By. ie G. Hutton, ‘Summary of the Results in selecting and propagating Paradise Stocks.’ 9. Farm Life, Oct. 2, 1920. 10. Quarterly Journ. Forestry, 14, pp. 253-257 (Oct. 1920). 12. Cf. ‘Solubility of Mineral Phosphates in Citric Acid,’ pt. ii., Journ. Sec. Chem. Industry 35 (1916); Notes on the Nature of the Phosphates contained in Mineral Phosphates,’ in Journ. Agric. Science, 8; ‘ Trials on Grass Land with Open- hearth, Basic Slag and Rock Phosphates,’ in Journ. Boord of Agriculture, 24 (1918). 18. Summary in Gardeners’ Chronicle, Sept. 18, 1920, p. 189. Results expected to be published in Journ. Roy. Horticultural Soc. EVENING DISCOURSES. ile Tuurspay, August 26. Some Requirements of Modern Aircraft. By Sir R. T. Guazeprook, K.C.B., F.R.S. The differences between the requirements of military and of commercial flying are not merely due to the fact that the military flying machine has developed into a formidable weapon, whilst commercial aircraft must be a means of rapid transit and transport. The lecturer quoted from a paper, recently communicated by Squadron Leader R. M. Hill, to characterise these differences : ‘If commercial aeroplanes are to compete successfully with other forms of transport, they must compete on grounds of economy, speed, and reliability, but such achievement will not be of the slightest value until a standard of safety nearer to that reached by railways and shipping is attained. The most pressing difficulties seem to be those of flying to a place and landing when there is a mist down to the ground, of the comparative unreliability of the light aero-engine, of the space which any aeroplane requires to land in, and of the imperfect control of small aeroplanes at low speeds and of large ones at any speeds.’ The lift, the upward force on an aeroplane, is greatest for an approximately rectangular wing when the long side is horizontal and at right angles to the direction of flight, when the lift W=/, p & v?, where p is the air density, s the area, v the speed of the machine, and k, the lift coefficient, depending both upon the section of the wing and on the angle between the bottom chord of the Fig./. POSSIBLE LOADING OF WINGS & BODY OF HIGH SPEED AEROPLANE IN FLIGHT. a BE2 Type Machine with 150HE Engi ucts 1 Max. Speed trom Horizontal Fight -110MPH. Tailp tora asinBE2c. ||| fir Weight of Machine -1930Lbs. in er ing out trom a vertical nase dive | 254 T=-18 b stgier beenreached. kutial Speed=157 MPH. ar=0-4° i : 018 Secs pee 160 ToadFactor on Wings mw gn = A= BZ Load,on Tail in Lbs per'S +¥e)= joerg Angle of Incidence of =a U=165 Forward Speed in Miles per Hour =U am 200 T=4 a-4 U-148 3 Aat etd = 6560.4.) 300 200 100 oo wing and the flight direction, 7.c., the angle of attack. As the angle of attack increases, and the wing is held more and more obliquely, the lift coefficient increases until the angle is about 15 deg.; at this, known as the stalling angle, k, suddenly drops, and the wing ceases to support the weight it has borne. The actual values reached by i; before stalling differ appreciably ; 0°6 or 0°7 is about EVENING DISCOURSES. 385 the usual maximum, but 0°9 has been exceeded by Messrs. Handley Page and by the Blackburn Company. The stalling speed, the minimum speed at which the machine can fly, is inversely proportional to the square root of the maximum lift coefficient, and since W=k,psv*, W/s=k,pv’, this quotient expressing the ‘loading,’ i.¢., the weight carried per unit wing area; the loading varies between 5 lb. and 10 lb. per sq. ft. The drag or resistance to the motion of the wing is equal to k,psv’, the drag coefficient £, also depending upon the shape of the wing section and the angle of attack. As that angle increases, k, decreases at first, then increases more and more as the angle grows steeper. But kz is always smaller than k,, and the force D required to move the wing is given’ by D=W &,/k,. The resistance of the rest of the machine is about the same in amount as that of the wing. The resistance is entirely due to the friction 1g... POSSIBLE LOADING OF WINGS & BODY Fgd OF HIGH SPEED AEROPLANE IN FLIGHT. fo 7 - 260 CC ae ee TT To ad oie oes 4. vay ‘ - L208 A | 3se HN a6 3 PTT 00 s 7-0 re AA tat-3 a \e-iae Ke psa pe Bs AZYMPN, ee Load.Factor ow a9 ts \ {z 3-85 Load mTail-T ths, . * tars 2 ei ig (act e 6 peppy males/ro: B.E.2. MAGHINE WITH 450 HP ENGINE. Weight - 1930 Ubs. Resistance in normal flying altitude -340 lbs. at 100 fs. Mac. hordctttad flight Bmp 1290 trol leverages as uy B.E. 2c. Sipe ane aaa ae opole : aUNL LL LEE ECET ECE must rol loop. a Oe In 4 Oo. 6 7a, 8 (6560.8) Seconds. between the moving body and the air, and to the viscosity of the air, the friction itself is due rather to the eddies, which owe their origin to the viscosity, than to the direct motion of the machine through the air. As regards the engines, the weight per horse-power is smaller for radial air-cooled engines than for water-cooled motors ; 3 lb. per horse-power is perhaps a reasonable figure. According to Bairstow, a light aeroplane capable of travelling at 125 miles p.h. would be able to carry a useful load of 270 lb. out of a total weight (machine, engine, and pilot) of 2,100 lb. The modern Bristol Pullman triplane for fourteen passengers, capable of a best speed of 130 m.p.h., weighs empty 11,000 lb., and fully loaded 18,000 Ib., 4,375 lb. of that total being available for cargo or passengers. The engines are not yet reliable in the sense that marine engines are reliable. The useful load can be increased by making the structure light. A light md¢hine can be flown at a lower angle of attack, but the structure must remain sufficiently strong, and the calculation of the stresses is not an easy matter, except when the machine is moving horizon- tally. In steep diving, at twice normal speed, the stresses might rise to sixteen times their magnitude for normal] flight, if the pilot were able to change his con- trols instantaneously, and although that is impossible, the controls can be changed within one-fifth of a second. For these calculations the ‘load factor’ is 1920 co 386 EVENING DISCOURSES. important, this factor indicates the ratio of the stress in any part of the structure under given conditions of flight to the stress under normal conditions of horizontal flight. The load factor during recovery from a dive can be determined in two ways. Starting with an aeroplane diving at a given speed we could calculate the initial stresses on the parts, and if we knew the aerodynamic forces, the values of k; and the resistances of the various parts, and were able to make some assumption as to the rapidity at which the pilot altered his controls, we could determine mathematically the rest of the path and the stresses on the machine at any point of that path. Fig. 1 shows the results of that calculation for a machine flattening out from a dive, and Fig. 2 the results from a machine doing a loop. In both cases the machines were moving at high speeds, and high load factors were required for safety. In the former case the pull on the control levers was 160 Ib., reached after 0-18 second ; in the latter case it was 100 lb., attained in about the same period. The other method of determination relies upon the experimental measure- ment of the forces on the machine as a whole by the aid of accelerometers. On aeroplanes pendulums of heavy weights or springs of high inertia, which would go on swinging, would be useless. The accelerometer used took the form illustrated in Fig. 3. It consisted of a quartz fibre, 1/2,000th in. in diameter, Fig.3. ACCELEROMETER bent to an arc A B C, and held, normally, in a horizontal position. The fibre would be slightly deflected downwards by its weight, and would be still more deflected by a vertical acceleration, and this additional deflection of the point C to positions C, or C, was recorded photographically. The accelerometer camera and the lamp were contained in a small box strapped to the observer’s knee. The curves thus obtained indicates only the accelerations of the centre of gravity, without taking account of the twists and turns about this centre. The kinematograph has also been utilised at the Royal Aircraft Establishment for the determination of the stresses. A kinematograph was fitted on to the tail of one machine rising steadily, while the second machine following close behind performed the loop spin, or other evolution, it was desired to analyse. Series of these photographs were exhibited. \ A- commercial machine should be stable, as it would be impossible, without a great expenditure of the pilot’s energy, to fly through a continuous cloud. Yet stability pushed too far gave the machine a will of its own and made it sluggish, and military pilots, to whom rapid contro] meant life or death, differed as to the desirability of stability. On the other hand, the stable machine would fly on, if the pilot lost control, and, if the engine stopped, the machine glided down, while the unstable machine got into a spin and crashed down to earth. Stability may be automatic or inherent. Automatic stability, secured by con- trivances which came into play when a deviation from the steady course occurred, is unsatisfactory because the device necessarily takes some time to operate, overshoots the mark, and hunts. An inherently stable machine would be brought back to the steady state by the disturbing wind forces. The lecturer indicated how, thanks mainly to the labours of Bryan and Bairstow, longitudinal stability, at any rate, had been successfully secured; our knowledge of the conditions for lateral stability is unfortunately far less complete. Longitudinal stability is important in connection with looping. It is known that an unstable aeroplane has a stable flying position on its back. If it got into that position BVENING DISCOURSES: 387 by some accident, it could only be righted again with the greatest difficulty, if at all. od The lecturer finally referred to the difficulties which the aviator, as distinct from the sailor, had with his navigational instruments. The aviator does not know whether or not he is moving uniformly. A bubble level indicator will only tell him that the acceleration, if any, is at right angles to the surface of the bubble. The compass is disturbed by the vibrations of the engine, to damp the effect of these the whole compass is encased in a closed vessel usually filled with alcohol. In the ordinary compass, the card carrying the magnets is fitted with a cup resting on a pivot. The vibrations make the card rotate and set the liquid in motion; to reduce these movements the vessel is made spherical, the pivot and cup are interchanged, the cup being attached to the support, and the card itself is replaced by a short length of a cylinder having the cup on its axis. Even thus improved the R.A.F. spherical compass, of which Fig. 4 gives a diagrammatic section, will, on an initially northern course, move to the east or west, only, say, 10 deg., when a turn of 15 deg. has been made, because, in describing the curve, the aeroplane is banked inwards so that the axis of the magnet card does not remain vertical, and the directive force on the magnet is no longer the full horizontal component of the earth’s field. Moreover, the compass cannot take up its position instantaneously. When the compass turns more quickly than Fig 4. RAF SPHERICAL COMPASS. DASHBOARD MOUNTING. DIAGRAMMATIC SEC. Bezel. Filling Screw. Rubber Jointing Strip Glass wilh Spherical LubberLinel $ server SHER gr. Outer Case, | Brass Bowl Cylindrical Card Eapansion gsi P em Carrying Sapplure Cup. (65600) Holder for Adjusting Magnets. the aeroplane, the observer would at first imagine that he was steering towards the west when he was really turning eastward. This trouble could be remedied by making the time of swing of the needles long compared with the time taken by the machine to complete its turn. On a northerly course the turn would then appear in the right direction, though too small in amount; on a southerly course the turn would also appear in the right direction, but too large in amount. The aviator’s trouble with the sextant is that he is rarely able to take a horizon reading, and even if he can that reading would have to be corrected for the dip of the real horizon below the level of his machine. In the bubble sex- tant, illustrated in the diagram Fig. 5, the image of the bubble is visible at the same time as the distant object. The observer has to bring the object to appear in the centre of the bubble and to bring the two on the axis of his observing telescope. But, as in the case of the compass, the observer should be sure that, at the moment of reading, he is flying uniformly without acceleration. His speedometer gives him his rate of motion through the air, and, with a steady wind, he would know that he was flying at constant speed. His altimeter aneroid, or his climbmeter, would enable him to keep on a horizontal path, but he still needs something to tell him whether he is flying straight or on some curve. The turn indicator gives him this information. When he banks on a curve, the extremity of the outer wing is higher up and moving faster than the inner-wing extremity, and there is a difference of pressure at these two points; a small difference, of course, yet measurable by Sir Horace Darwin’: oo 388 EVENING DISCOURSES. turn indicator, which marks zero when the aeroplane is travelling straight. In the gyro-turn indicator, developed at Farnborough, the principle of which is explained by the diagram Fig. 6, the gyro-wheel is placed outside the machine Stlvered Face 4 (6560.4) so as to rotate in a vertical plane at right angles to the direction of flight, the rotation being maintained by the wind playing upon suitable holes in the wheel. If the machine when moving straight horizontally begins to turn about a vertical axis, a pointer attached to the gyrostat indicates that motion or, if controlled by a spring, shows the force tending to make the gyrostat move. There remains the dangers from mists and fogs, which are more formidable to the aviator than to the sailor. The sailor has fog signals, leader cables, buoys, and harbour lights to guide him; the aviator frequently has little warning that he is within a few feet of the ground. Captive balloons, if feasible, are themselves sources of danger; sound signals would not be appreciated by the neighbours of aerodromes; signal beams do not penetrate far through mists ; radio-telegraphy and radio-telephony promise best. But the landing troubles and means of control at low speeds, as well as the construction of reliable aero- engines, remain urgent problems of modern aircraft. EVENING DISCOURSES, 389 II. Fripay, August 27. A Grain of Wheat from the Field to the Table. By Sir Danten Hat, K.C.B., F.R.S. In the history of mankind there are no processes older, more essential, or more universal than the growing, grinding, and baking of wheat and its kindred food grains. What, then, has the British Association to do with so fundamental a busi- ness, brought to something like perfection long before anything we can call science existed ? That is precisely what I want to tell you to-night. Countless years have elapsed since primitive man took the momentous step of sowing a little of the wild grain he had hitherto been content to gather, in the hope of saving himself some trouble in collecting the next year’s crop. Millions of men have spent their lives in growing wheat. All sorts of rewards— nay, the very life of the community—have attended on improvements in the crop. What can there be to learn about it now? Yet at every stage in the story of the grain of wheat from the seed-bed to the breakfast table we find that we do not know what we need to know in order to get on with the business of making two grains grow where one grew before. I want to show you that, however old, however fundamental the industry, science comes in at every turn, and research, calling for all our imagination, skill, and determination, is required if progress is to continue. All biologists would agree that development demands an abundant food supply, just as fine flowers want a fat soil. Now, the population of the world is rapidly growing up to, if it has not for a time exceeded, its available food supply, and only by research and the utilisation of the fruits of that research are we going to obtain more food. If I had to name one remedy for the present discontents it would be more wheat, and as we are nearing the limits of the potential wheat land we must therefore set about the other problem of getting more from what land we have. Beginning with the grain of wheat, we find it consists of a tiny embryo, that part that possesses life, and the endosperm or food store, which is to nourish it until it can push a green leaf above the ground and begin to feed upon the air and the soil. The embryo’s food store is our food supply; flour is only the powdered endosperm. In its dry state, when it cannot draw upon the endosperm, the embryo soon dies, and with it the whole grain; some in one year, more in two; few can survive for ten years. Mummy wheat is a myth. Can you excite the seed before sowing by electricity or other means to grow better and give a bigger crop? Experiments are being made, but the results are dubious. Probably not, because the seed only starts the plant in life; its growth and yield depend on development after the start, on the soil, the manure, the weather. Tt is usual in England to sow two and a-half bushels of seed wheat to the acre; properly managed, half a bushel or less would cover the field with the necessary plants for a maximum crop. Experiments are on foot to get a machine that will sow economically. Even if we can save a bushel an acre of seed the country would gain 3 per cent. of its output of wheat, worth well over a million pounds a year. There are hundreds of kinds of wheat—early and late, tall and short, close- packed or open in the ear, varying in colour and size and in other ways. Each sort breeds true because the flower is self-fertilised. If we pick out each year the longest ears in the field, or the plumpest berries, and grow only from them, no improvement results. Selection of this kind has been tried for fifty years without result. Change, and with it improvement, only comes when varieties are crossed; then we get new varieties. The scientific breeder working on Mendel’s principles can in a few years raise and fix a new wheat, combining the sood points of both parents. New English wheats have been bred in the 390 EVENING DISCOURSES: last few years which raise the produce per acre of Hastern County farms by at least 10 per cent. For all its vigour, wheat cannot stand the competition of weeds. At Rotham- sted a crop was left unharvested to sow itself without cultivation. In three years the wheat had entirely disappeared in the wilderness that grew up. Nevertheless, wheat has, more than any other cultivated plant, the capacity of growing upon all sorts of soils, even the poorest. At Rothamsted, on one of the plots, wheat has now been grown for seventy-seven successive years without any manure, and it still yields about twelve bushels to the acre, pretty much the average crop of all the wheat lands of the world. Wheat is the crop for breaking in the wilderness. In the new countries the settler always begins with a succession of wheat crops before he resorts to mixed farming. Experiments haye long since settled what manures wheat wants. The real trouble now is to get the big crops grown with plenty of manure to stand up, and this is a problem now being attacked in various fashions—stiffer-strawed varieties, special cultivation, and corrective manures, etc. The wheat plant practically finishes growing a month or five weeks before it is harvested. In the last period the valuable material is being moved from stem and leaves to the seed. The migration is incomplete; half or less of the stuff manufactured by the plant gets into the seed, and here are great possibilities of improvement. The object of the modern flour miller is not to grind wheat into a meal and then sift out the flour, but to crack the berry without breaking the husk (bran) and let the endosperm fall out. The best white flour is pure endosperm. It is the most digestible part of the grain, and weight for weight yields the most food. In peace times only two-thirds of the grain is recovered as flour, but under war conditions it was necessary to use the less digestible portions as well, and the extraction was raised from 68 to well over 90 per cent. Though imperfectly digested and not suited to all constitutions, the higher extraction was equivalent to an extra two months’ supply of wheat. Flour from most English wheats produces small dense loaves; certain Canadian and other foreign wheats give big spongy loaves, which the public prefer. A wheat was found that retains this property of strength in the English climate. This wheat crops badly, but the wheat-breedez is at work combining the strength of this (Fife wheat with the cropping power of English wheats. Professor Biffen’s ‘ Yeoman’ wheat, on suitable soils, is now the biggest cropper known, and gives flour as strong as Canadian wheat Before the war we only grew one-fifth of the wheat we ate; the rest came from North and South America, Russia, India, and Australia. Some of these foreign supplies have been cut off, and the world’s supply of wheat will be short for years to come. As a national insurance we must grow more at home, and this can only ibe done by better skill and more knowledge, because we cannot expand our land indefinitely. We must not grudge expenditure on knowledge; our food supply in the future depends upon the advancement of science, which is the purpose of the British Association. CORRESPONDING SOCIETIES COMMITTEE. Corresponding Socielies Committee. Report of the Committee con- sisting of Mr. Winit1am Wuiraxer, F'.R.S. (Chairman), Myr. Witrrep Mark Wess (Secretary), Mr. P. J. Asuton, Dr. F. A. Baruer, F'.R.S., the Rev. J. O. Brvan, Sir Epwarp BrapBroox, C.B., Sir H. G. Forpuam, Mr. T. Surpparp, the Rey. T. R. R. Sreppinec, /'.R.S., Mr. Marx Sykes, and the PRresmIpENT and GENERAL Orrrcers of the Association. (Drawn up by the Secre- tary.) E: Tur Committee reports that the following are the officers of the Conference of Delegates to be held at Cardiff: President, Mr. T. Sheppard, M.Sc., F.G.S. ; Vice-President, Mr. F. W. Sowerbutts; Secretary, Mr. Wilfred Mark Webb, F.L.S. ; and that the programme is as follows :— Wednesday, August 25, at 2 p.M.—(1) Presidential Address by Thomas Sheppard, M.S8c., F.G.S., on ‘ The Evolution of Topographical and Geological Maps.’ (2) Paper on ‘ Railways and their Obligations to the Community,’ by A. H. Garstang, Secretary of the Railway Facilities Sub-Committee of Section F. Friday, August 27, at 2 p.m.—Discussion on ‘ The Status of Local Societies: the means of developing their objects, of getting new members, of publishing papers and making announcements,’ which will be opened by William Whitaker, B.A., F.R.S. After the meeting the Delegates will be entertained to tea by Principal A. H. Trow, D.Se., F.L.8., President of the Cardiff Naturalists’ Association, and will have an opportunity of seeing the Exhibition, illustrating the Presidential Address and the work otf local Societies. The Committee recommends that the Offa Field Club, Oswestry, be admitted as an Affiliated Society, and the Scottish Natural History Society, the Darlington and Teesdale Naturalists’ Field Club, and the Greenock Philosophical Society as Associated Societies. The Committee asks to be reappointed, with a grant of 40. ray At the first meeting of the Conference of Delegates on Wednesday, August 25, the President, Mr. T. Sheppard, delivered the following address :— The Evolution of Topographical and Geological Maps. One of the secrets of successful collecting—and every scientific man is a col- lector in some form or other—is to secure series of certain specimens or objects for which few people, if any, are in search. In this way it is possible to contribute something tangible towards the advancement of science. _ On a previous occasion I had the privilege of bringing before your notice information relating to the past difficulties in connection with the exchange of currency, clearly demonstrating the necessity for the decimal system of weights and measures. (See ‘ Rep. Brit. Assoc. for 1917,’ pp. 228-235.) That paper was made possible by collecting old boxes of money scales and weights, a few years’ work resulting in the finest series of English examples in existence being gathered together. In the same way, and for somewhat similar reasons, collecting old topo- graphical and geological atlases and maps was indulged in, and by methods familiar to experienced collectors, examples of old road-books, charts, and geological plans, diagrams, and maps began to accumulate to an extent which was positively alarming ! 392 CORRESPONDING SOCIETIES. On the topographical side, a predecessor of mine in this chair, Sir George Fordham, exhibited before the British Association at the Dublin and Dundee meetings in 1908 and 1912 respectively, a fine series of old road-books. With regard to geological maps, however, which naturally follow the topographical series, nothing systematic seems yet to have been accomplished, and it is extra- ordinary how this most valuable source of information has been neglected— even by our special geological societies. A few years ago the Geological Society of London asked me to prepare a Catalogue of British Geological Maps, and the work has occupied nearly all my ‘spare time’ ever since, as will be under- stood when I say that the Catalogue, as yet in manuscript, contains details of thousands of such maps. The preparation of this, and the collecting of old maps and charts, has resulted in the accumulation of facts which will, I think, be of interest to the delegates of the Corresponding Societies, and, it is hoped, will give them an idea of the method of obtaining, from sources which are usually neglected, information relating to the physical geography and geology of their respective areas. I possess ‘ Edward, Duke of Norfolk, Earle Marshall of England’s’ copy of Moll’s ‘ New Description of England and Wales,’ dated 1724. It consists of fifty maps, measuring 10 by 74 inches. Each map is folded, and mounted in the middle on guards, so that no information is lost or distorted in the binding. The volume measures 73 by 8} inches. Bound up with it is a map of ‘The Roads of ye South Part of Great Britain Called England and Wales,’ by Herman Moll, Geographer. It is dedicated to Frederick Prince of Wales (and therefore must be after 1729), and contains the following engraved upon it: ‘ Note: This map has been copied four times very confused and Scandalously’! Pre- sumably by other ‘ enterprising’ publishers. On the margins of each of the county maps various ‘curios’ are engraved, usually ‘bearing upon the district. For example, the first map, Bedford Shire, is decorated by representations of obverses and reverses of six Roman coins, in the execution of which—as in other illustrations—the artist has had very fair licence. Besides giving evidence of changes due to coast erosion, alterations in estuaries and river channels and lakes; these old maps yield much interesting geological information, albeit the ‘Geographer, Moll,’ knew not the science of geology. On the map of Cornwall, for instance, not only are the mines indi- cated, and their names and depths given, but details occur of the various metals obtained—tin, copper, and lead; there are ‘ lead mines producing much silver,’ and even ‘ ancient lead mines.’ On the margin is engraved ‘ The Wring Cheese ‘Stones near Rillington,’ the ‘ Hurlers’ Stones,’ etc. Thus this map not only indicates the extent to which mining for metals was practised precisely two centuries ago, but gives evidence of mining in still earlier times. Black-lead_ mines, copper mines, and lead works are shown on the Cumber- land map. That of Derbyshire is dotted over, ‘to a surprising extent, with triangular marks indicating lead mines: the margins being devoted to repre- sentations of geological ‘curios,’ as well as engravings of ‘Poole’s Hole’ and another cave named after a portion of the anatomy of the devil. These illus- trate the characteristic weathering of the local Carboniferous Limestone. The fossils are better engraved than described. An obvious Huomphalis is ‘A Petrify’d Cockle’; a Productus is ‘A Petrify’d Oyster’; a piece of encrinital limestone is ‘A Terrene course Fluor or Spar found in the Lead Mines’; a Silurian Brain-Coral has somehow crept in, and is ‘ Bufonites or Brain-stone, viz. from ye Representations; it Bears to a Toad.’ A chalk echinoderm— which has also strayed—is ‘One of the Echini Petrify’d with the Representa- tions of Trees,’ the ‘Trees’ being the lines between the plates forming the test. Two sharks’ teeth, suspiciously Tertiary, are ‘A Glossopetra or Crow- bill found in ye Lead Mines,’ and ‘A Glossopetra found in the like Mines both in this County and Wales,’ respectively. The Devonshire map indicates lead, tin, and copper mines, ancient lead mine, and ‘Z'he Most Ancient Copper Mine.’ Lead mines and ‘Ooal Pitts’ occur on the Durham map, as well as ‘Hell Kettles’ and other natural features. On the Essex map are two engravings labelled ‘Near Tilbury are several Arti- ficial spacious Caverns built with Stone in a Chalky cliff to ye height of 10 PRESIDENTIAL ADDRESS. 393 Fathom. as nere represented,’ but the artist had not quite understood the structure of the dene-holes (as now named); his plans are all right, but the shafts are drawn above ground like factory chimneys. The Lincolnshire map indicates the former appearance and extent of the Fens and the Wash, and with it is ‘A Perpetual Tide Table for Foss-Dyke and Cross-Keys Washes in the county, showing from the Moon’s Age the exact time of Full Sea of ye beginning and ending of the Wash, or when Travellers may safely pass over.’ The Northamptonshire plate shows a pear-shaped mass of Serpule labelled “A Vertebra or single Joint of the Back-Bone of a large fish. “Tis two inches and a half in length, and near as much in breadth. Digged up at Peakirk almost 4 foot deep in the Earth.’ A well-known Oolitic coral is ‘ Astroites, or Star Stone, with round radiated holes in its surface found at Cartenhall ’; two Kimmeridge Clay Ammonites are ‘‘A Five wreath’d double straited (sic) Ammonia found in Oxenden’ and ‘ The Studded Ammonites Modiolaris found near Towcester.’ Another is ‘A Four wreath’d Ammonites found at Marston russel.’ ‘Lead Mines and Coal Pitts’ are indicated on the Northumberland map. On that of Shropshire it is amusing to read that ‘or want of antiquities, &e., in the county we have inserted some out of ye Neighbouring County of Staffordshire.’ Five ‘Form’d Stones partly Cylindrical’ are clearly encrinite- stems, and four organ-pipe and similar corals are labelled ‘ Minerall Coral,’ ‘Museus Pyreidatus found near Stansop,’ ‘ Honey Comb Stone,’ and ‘A Form’d Stone like a Stool of Reeds’ respectively. For the same reason the Worcester map is decorated by specimens alleged to have been found in Staffordshire, though in this case minerals as well as fossils are given. In addition to ‘Lead Mines and Coal Pitts,’ ‘Allom Works’ are indicated on the ‘North Riding of York Shire’ map, the last referring to a one-time flourishing industry in ‘the Whitby area. On the East Riding of the same county ‘Sunk Island’ is shown as an island in the middle of the Humber—an area now joined to the mainland—as a result of which one-time seaport towns are now far inland; similarly, on the sea-coast, towns are shown which have since been entirely washed away by the sea. On the South Wales map a frond of Neuropteris and a fragment of Sigil- laria are given as ‘Mock Plants out of a Cole Pit near Neath in Glamorgan- shire,’ and presumably examples of ‘The sport of Nature, aided by blind chance, Rudely to mock the works of toiling man.’ I have mentioned only a few contents of this old atlas, but I trust it has been demonstrated that, two centuries ago, information now of great value, both geographically and geologically, was being placed upon these maps. Mboll’s work is only one of scores which were issued, some earlier, some later. What I wish to emphasise is the necessity for preserving these maps and atlases before it is too late. Each county society should collect, store; and eventually catalogue and describe the maps relating to its area. During the past few weeks three different booksellers have sent me books wrapped up in county maps, or, more annoying still, parts of maps. In one ease I asked if any others were available similar to those used for packing. 1 secured those I required, but at a price which clearly indicated that the “packing * was about as valuable as the books! I am sorry to say that the systematic compilation of lists of county maps has only as yet been accomplished for a very few areas, and we thus have many more ‘imperfections in the geological record’ than are really necessary. DN N DB ND BeW waaeHeW eS UD CORRESPONDING SOCIETIES. A. E. J. Carrer. [Diptera at Aberfoyle], loc. cit. Oct., p. 233. Also noticed in Scot. Nat. Nov., p. 202. B. A. Carter. Greenshank in Warwickshire. Brit. Birds. July, p. 61. J. W. Carter. Symvetrum sanguineum Mull., a Dragon-fly new to Yorkshire. Nat. Dec., p. 299. Newuire Carrer. On the Cytology of two Species of Characiopsis. New Phy. May, pp. 177-186. —--- Studies on the Chloroplasts of Desmids. Ann. Bot. July, pp. 295- 304. H. E. Gastens Black-necked Grebe on Kent and Sussex Border. Prit. Birds. July, p. 60. G. C. Cuampron. Note on a dark form of Liopus nebulosus Lion. Ent. Mo. Mag. July, p. 158. —— Another note on the habits of Melanophila acuminata De Geer, loc. cit. Aug., pp. 177-178. —— Hemiptera, etc., in the New Forest, loc. cit. Sept., p. 209. Epaar Caance. Observationson the Cuckoo. Brit. Birds. Sept., pp. 90-95. Aprn Crapman. Bird-Notes on the Borders, 1918-19. Vasculum. Dec., pp. 152-155. T. A. Caapmay. Note on Hoplocampa testudinea Klug. Ent. Mo. Mag. June, p. 138. —— Trichiosoma tibiale and Acampsia pseudospretella, loc. cit., pp. 1388-129. S. A. Crartrers. D. nerit at Eastbourne. Ent. Rec. Oct., p. 188. ——- Late appearance of Agriades coridon, loc. cit., p. 226. Curtis. A. CoerrHam. Yorkshire Diptera Notes. Not. July, p. 244. —-- Xiphura atrata L. in Yorkshire, loc. cit. Dee., p. 380. —— Yorkshire Naturalists’ Union, Rotanical Section, Joc. cit., p. 389. —— Additions to Yorkshire Diptera, loc. cit., pp. 394-395. --— See T. SHEPPARD. —-— See W. EF. L. Warram. Mictvrk Curisty. Hornets, Wasps, and Flies sucking the sap of Trees. Essex Nat. Vol. XIX., pt. 1, pp. 10-14. —— Qn the Arboreal Habits of Field Mice, Joc. cit., pp. 18-21. —— Fungus on Stem of Oak Tree, loc. cit., p. 48. —— Samuel Dale (1659 ?-1739) of Braintree, Botanist, and the Dale family : some genealogy and some portraits, loc. cit., pp. 49-64 [continued in 1920). A. H. Cuurcu. The Plankton-phase and Plankton-rate. Journ. Bot. June Supplt., pp. J-8. —— The Building of an Autotrophic Flagellate. Bot. Memoirs. No. J, pp. 1-27. —— Thalassiophyta and the Subzrial Transmigration. No. 3, pp. 1-95. -_—. Elementary Notes on Structural Botany, Joc. cit. No. 4, pp. 1-27. —— Elementary Notes on Reproduction of Angiosperms, loc. cit. No. 4, pp. 1-24. —— Brunfelsand Fuchs. Journ. Bot. Sept., p. 233. ——- Historical Review of the Pheophycee, loc. cit. Oct., pp. 265-273. —— Historical Review of the Floridex.—I., loc. cit. Novy., pp. 297-304 ; II., Dec., pp. 329-334. —— The Ionic Phase of the Sea. New Phy. Oct., pp. 239-247. Ricwarp Crarnam. Footprints of the Wild. Animal World. Dec., pp. 137-138. J. Eomunp Crarx. Garden Phenology, Asgarth, Riddlesdown Road, Purley. Proc. Croydon N. H. & Sci. Soe. Vol. VIIL., pt. v., pp. elxvii-clxviii. Wm. Faatr Crarke. The Starlings of Shetland, Fair Isle, and St. Kilda. Scot. Nat. Nov., pp. 183-185. —— Wild Swans observed on the Western Islands in Summer, Joc. cit., pp. 196-197. W. G. Guarke. Three Old Essex Herbaria. Hssex Nat. Vol. XIX., pt. 1, pp. 23-25. —-— Some Essex Plant Records, Joc. cit., pp. 47-48. ——- W. Allen Sturge, M.V.O., M.D., F.R.C.P. [Obituary]. Proc. Prehist. Soc. E. Anglia. Vol. III., pt. 1, pp. 12-13. : NN N NN NNNN® &@ N N N NNNNN NNN OQ @O NNNNNNN &@ NNN N DV N NNN WV LIST OF PAPERS, JUNE—DECEMBER, 1919. 415 W. G. Cuarke. The Distribution of Flint and Bronze Implements in Nor- folk, loc. cit., pp. 147-148. W. J. CuarKke. Large Yorkshire Trout. Nat. July, p. 245. W. G. CnuTtren. Colour Variation of Odezia atrata. Ent. Nov., p. 256. C. GRaNVILLE ChuTTEeRBUCK. Pselnophorus brachydactylus in Gloucester- shire, loc. cit. Dec., p. 275. E. A. Cockayng. Inheritance of Colour in Diaphora mendica Cl. and var. rustica Hb. Ent. Rec. June, pp. 101-104, C. V. Cotnizr. Thomas Boynton, F.S.A. [Obituary]. Yorks. Arch. Journ. Pt. 98., pp. 271-272. Watrer E. Cottiser. Some Remarks on the Food of the Barn-owl (Strix flammea Linn.). Journ. Wild Bird Inves. Soc. No. 1, pp. 9-10. —— Two interesting cases of Melanism, loc. cit., p. 15. —— Strange accident to a heron, loc. cit. —— Wild Birds and Distasteful Insect Larve. Nature. July 24, p. 404; Aug. 21, p. 483. E. J. Coutins. Sex Segregation in the Bryophyta. Journ. Genetics. June, pp. 139-146. A. H. Cookr. ‘Ground’ Clausilias. Journ. Conch. Aug., p. 102. J. E. Cooper. See Anon. A. Strven Corsut. Argynnids in Wiltshire. Ent. Dec., p. 278. H. H. Corserr. Woodcock near Doncaster. Nat. Oct., p. 336. —— Cormorant at Doncaster, loc. cit. Novy., p. 371. —— See W. E. L. Warram. Ernest CornELL. Some Notes on the Butterflies of the South Coast of the Isle of Wight, 1919. Ent. Dec., pp. 279-280. A. D. Corton. The Occurrence of Oak Mildew on Beech in Britain. Trans. Brit. Mycol. Soc. Sept., pp. 198-200. —— Entomogenous Fungi new to Britain, loc. cit., pp. 200-203. —— and E. M. Waxkerietp. A Revision of the British Clavariae, loc. cit., pp. 164-198. T. A. Cowsrp. Night-Heron in Anglesey. Brit. Birds. July, pp. 58-59. —— One pair of Meadow-pipits feeding two young Cuckoos, loc. cit., p. 139. —— Notes on the Vertebrate Fauna of Lancashire and Cheshire. Lanc. & C. Nat. Oct., pp. 89-100; Dec., pp. 159-162. E. Crise. Papilio machaon in Sussex. Ent. Oct., p. 236. —— AHyloicus pinastri in Suffolk, loc. cit. Nov., pp. 257-258. 5. G. Commines. Unusual site for Chiffchaff’snest. Brit. Birds. June, p. 27. —— Breeding Habits of the Nightjar, loc. cit., pp. 2° -28. Joun Currie. Common Scoter on Duddingston Loch in May. Scot. Nat. Noy.. p. 197. J. W. Curmorr. Some Notes on the Rats of the Port of Liverpool. Proc. and Trans. Liverp. Biol. Soc. Vol. XXXIII., pp. 68, 69. +. G. D. Hereward Chune Dollman, F.E.S. [Obituary]. Ent. Mo. Mag. June, pp. 139-140. Cuarues A. Dantas. Woodecocks perching on Trees. Brit. Birds. Oct., pp. 142-143. A. A. Datiman. Galiwm erectum Huds. in Cheshire. Lance. & C. Nat. Sept., p. 73. —— Geranium versicolor L. in North Wales, loc. cit. Oct., pall J. rrottiotr Dariinc. Pollan in Lough Ree. Jrish Nat. July, p. 93. —— Incubation of Birds, loc. cit., p. 93. Francis Darwin. A Phenological Study. New. Phy. Nov., pp. 287-298. G. MacDonatp Davies. Excursion to Norbury, Mitcham Common and Beddington. Proc. Geol. Assoc. Vol. XXX., pt. 1, pp. 75-81. W. Davigs. Pied Flycatcher in Staffordshire. Brit. Birds. Sept., pp. 107-108. J. T. Dawson. Art Gallery and Museum. [Additions.] 48th Ann. Rep. Rochdale Public Lib. ete. Committee, pp. 11-13. Frank H. Day. Carlisle Natural History Society. [Report.] Ent. June, p. 148. —— Westmorland Coleoptera. Nat. July, pp. 239-242 ; Oct., pp. 327-328. J. Davy Dean. Occurrence of Physa gyrina Say in Great Britain. Jowrn. Conch. Aug., p. 127. 416 N on N N NN BD BO WN ON DB weB WD NN N N N N NN NBO N N CORRESPONDING SOCIETIES. L. S. DEAR. Long-eared Owl laying twice in same nest. Brit. Birds. June, p. 30. Antuony W. N. Disnny. Lycena arion in North Cornwall. Ent. Sept., p. 216. Annie Dixon. Protozoa. Report on Gatherings from a Pond at Lawnhurst, Didsbury, from 14th March to 12th Sept., 1918. Lane. & C. Nat. Sept., pp. 74-81. —— W. Leacu, H. Benporr, and J. G. Kitcuen. Manchester Microsco- pical Society [Report], Joc. cit. Aug., pp. 61-63. H. N. Drxon. Mosses collected on Deception Island, South Shetlands, by Mr. James C. Robins [Abs.]. Journ Bot. July, p. 200. Lronarp Dorstn. On the presence of Formic Acid in the Stinging Hairs of the Nettle. Proc. Roy. Soc. Edinb. Vol. XXXIX., pt. 1., pp. 137-142. Horace DonistHoRPE. Wasps attacking Flies. Irish Nat. Sept., p. 107. —— A New County Record for Zeugophora flavicollis Marsh. Ent. Rec. Oct., pp. 185-186. —— The Myrmecophilous Lady-bird, Coccinella distincta Fold., its Lifé History and Association with Ants, loc. cit. Dec., pp. 214-222. —— Further localities for Platypus cylindrus F. Ent. Mo. Mag. Sept., p. 232. H. Downes. Juncus pygmeus Rich. Journ. Bot. Sept., p. 260. G. Cuartpce Drucr. The Botanical Society and Exchange Club of the British Isles. Report for 1918. Rep. Bot. Soc. Vol. V., pt. 11., p- 267-271. — Plant. ‘Notes, etc., for 1918 (mostly New ‘Plants to the British Isles), loc. cit., pp. 272-318. —— Noteson Publications, New Books, etc., 1917-18, ioc. cit., pp. 319-349. —— Obituaries. [J. E. Bagnall, Wilham Brack Boyd, Edward Fry, Joseph John Geoke, Reginald Philip Gregory, Edward Walter Hunnybun, Ernest David Marquand, T. W. ae William Frederick Millar, Bishop John Mitchinson], loc. cit., pp. 349-365. —— New County and Other Records, Joc. “Cit, pp- 365-412. —— The Dates of Publication of Curtis’s “Flora Londinensis,’’ loc. cit., pp. 412-414. —— Additions to the Berkshire Flora, loc. cit., pp. 443-480. —— Additions to the Berkshire Flora. Proc. ‘Ashmolean N. Hist. Soc. for 1918, pp. 21-58. Martin C. Ducnesne. Afforestation: Its Practice and Science. Rep. Brit. Assoc. for 1918, pp. 68-75. James Duncan. COolias edusa near Aberdeen. Hnt. Oct., p. 235. T. A. Dymes. Notes on the Life-history of the Yellow Flag (/ris Pseudacorus Linn.), with special reference to the seeds and seedlings during their first year. [Abs.]. Journ. Bot. Aug., pp. 231-232. F. W. Epwarps. Gnophomyia tripudians Bergroth: A New British Fly. Ent. Mo. Mag. Aug., pp- 176-177. L. A. Curtis Epwarps. Continental Jays in Oxfordshire and Sussex. Brit. Birds. Sept., p. 107. Rosr Eazrton. See W. 8S. LAvVEROcK. J. Sree Exniotr. Grey Wagtails nesting at a distance from water. Brit. Birds. Aug., p. 81. < —-—— Hobby in Shropshire and Worcestershire, loc. cit., p. 84. —— Large Numbers of Bramblings in Worcestershire, Ice. cit. Dec., pp. 194-195. GrorcE Exzison. The Nest of the Bank Vole. Proc. and Trans. Liverpcol Biol. Soc. Vol. XXXIII., pp. 65-66. —— Note on a White Orkney Vole, Microtus orcadensis, v.;«lba., loc. cit., p. 67. G. W. Exurson. Bank Vole (Evotomys glareolus, Schr.) nesting above ground. Lance. & C. Nat. Nov., pp. 124-125. Ricuarp Etmutrst. Orthocladius Spp. breeding in the sea. Scot. Nat. Noy., pp. 193-194. L. G. Esson. Zygena achillee in Argyllshire. Ent. Aug.,.p. 189. j i it. Nov.; p. 259. NN DWNNNUNN NNNN N N N NNNN NNNNNNN NNN DU N NNN NN NNNNOONN LIST OF PAPERS, JUNE—DECEMBER, 1919. 417 Wiu1AmM Evans. Boarmia gemmaria in the Forth Area. Scot. Nat. Noy., pp. 199-200. J. Cosson Ewart. Telegony. Nature. Nov 6, pp. 216-217. R. W. THomas Ewart. Capercaillie in Montrose. Scot. Nat. Sept., p. 156. Wm. Fatconer. The Spiders of Yorkshire. Nat. July, pp. 235-238 ; Aug., pp. 267-270; Oct., pp. 323-326; Nov., pp. 365-368; Dec., pp. 400-403. —— New and Rare British Spiders, loc. cit. Sept., pp. 295-302. —— Additions to the ‘ Spiders of Wicken,’ loc. cit. Nov., p. 356. ——- Plant Galls from the Searborough District, loc. cit. Dec., pp. 392-393. —— See W. E. L. Warram. H. H. Farwie. Late Nesting of Linnetsin Surrey. Brit. Birds. Dec., p. 195. —-— Grey Wagtails breeding in Kent and Sussex, doc. cit., p. 196. —— Greenshanks in Surrey, loc. cit., p. 198. ANDERSON Frrausson. Aspidiphorus orbiculatus Gyll., in Scotland. Scot. Nat. Nov., p. 200. —— Staphylinus cesareus, Ceder. in Main Argyll, loc. cit. —-- Halyzia 16-guttata, L., and Coccinella conglobata, L., in Main Argyl, loc. cit., p. 201. —— Additions to the List of Scottish Coleoptera, loc. cit. Sept., pp. 167-169. J. Dicey Firty. See W. E. L. Wartam. Epexram Fisier. Ornithology [Report]. Ann. Rep. Huddersfield Nat. etc. Soc., 1918-1919, pp. 13-15. N. H. FrrzHersert. Ornithological Record of Derbyshire, 1918. Journ. Derby. Arch. etc. Soc. Vol. XLI., pp. 170-178. H. J. Furore. Correspondence [Dolmen in Guernsey: quotes letter from Col. Guérin}]. Man. Sept., pp. 130-132. H. D. Forp. Aspilates ochrearia in Cumberland. Ent. July, pp. 167-168. —— Zephyrus quercus, var. bellus, loc. cit. Oct., p. 236. W. J. Forpusm. William Ernest Sharp, 1856-1919 [Obituary]. Nat. Aug., pp. 274-275. —— See W. E. L. Wartam. H, E. Forrest. Nightingales in Shropshire. Nat. Aug., pp. 277-278. —— Hoopoe in Shropshire. Brit. Birds. July, p. 57. —-— Shifting of Rreeding-grounds by Terns, loc. cit., pp. 61-62. —— Bar-tailed Godwits in Shropshire, loc. cit., p. 165. --— Little Owl in Montgomeryshire, loc. cit., p. 196. —— |[N. E. Forrest, error.} Little Owl Breeding in Shropshire and Radnor- shire, loc. cit. June, p. 30. R. Forrunr. Herons nesting in Nidderdale. Nat. Nov., p. 371. —— Black-necked Grebe in Washburn Dale, loc. cit. —— See E. A. Wooprurre-PEacock. Nevin H. Foster. Early Arrival of Redwings and Fieldfares. Jrish Nat. Sept., p. 107. —— A List of the Myriapoda of Ulster. Ann. & Mag. Nat. Hist. Dec., pp. 395-407. W. W. Flower]. [William E. Sharp, Obituary]. nt. Mo. Mag. Nov., 263 Hitperic Frrenp. Sparganophilus: A British Oligochet. Nature. July 31, p- 426. —— Luminous Worms, loc. cit. Aug. 7, p. 446; Nov. 27, pp. 334-335. —— British Well-worms, loc. cit. Sept. 4, p. 5. —— A New British Enchytreid Worm, loc. cit. Oct. 30, p. 174. F. W. Fronawxk. Nisoniades tages Imbibing its Excretion. Ent. Sept., pp. 212-213. —— Variation of Limenitis sibylla in the New Forest, loc. cit., p. 213. —— Variation of Dryas paphia, loc. cit., pp. 235-236. Martan Frost. Guide to the Worthing Museum and Art Gallery. pp. 1-16. GREEVZ FysHer. See W. E. L. Warram. —— See T. SHepparp. J. GARDNER. Plusia moneta, F. at Hart, Co. Durham. Ent. June, p. 138. L. V. Lester Gartanp. New County Records [Botanical] for Argyle. Jowrn. Bot. Nov., p. 322. + 1920 ; EE 418 N BD N NNN NN NN NN N NN NN UN NN @©@ DB DW NN 3B BW VUDVUD UVNNN N CORRESPONDING SOCIETIES. D. G. Garnett. Agrotis precor in Westmorland. Ent. Nov., p. 257. Margory GARNETT. Coloration of the Soft Parts of some Birds. Brit. Birds. July, p. 62-63. Watter GArstanc. Songs of the Birds. Nat. June, pp. 195-198. —— More Songs of the Birds, loc. cit. July, pp. 231-234. Sept., p. 281. —— Sea-fishery Investigations and the Balance of Life. Nature. Sept., 18, pp. 48-49, L. R. A. GAtEHousE. American Blue-winged Teal in Anglesey. Brit. Birds. Aug., p. 85. J. Bronth Gsatensy. The Identification of Intracellular Structures. Jewrn. Roy. Micro. Soc. June, pp. 93-118. —— Notes on the Bionomics, Embryology, and Anatomy of Certain Hymen- optera Parasitica, especially of Microgaster connerus (Nees). Journ. Linn. Soc. (Zool.). No. 224, pp. 387-416. A. GrepetEer. Jno globularie. Ent. Dec., p. 278. E. Lronarp Git. Crows, Rooks and Starlings versus Kestrels and Peregrine Falcons. Brit. Birds. June, pp. 23-25. —— Bird Notes from the Hancock Museum. Vasculum. Dec., pp. 156-157. FREDERICK GILLETT. Luproctis chrysorrhea on Hippophaé rhamnoides. Ent. Sept., pp. 215-216. C. T. GrmincHam. Some Coleoptera taken in Hertfordshire in 1918. Ent. Mo. Mag. July, pp. 157-158. —— Platyrrhinus latirostris, F. at Long Ashton, Somerset, loc. cit., p. 158. —— Some Coleoptera taken in Somersetshire, loc. cit. Aug., pp. 179-180—a correction, Sept., pp. 207—208. Huan 8. Guapsrone. Kite in Kent in 1822. Brit. Birds. Aug., p. 84. —— A Naturalist’s Calendar, kept by Sir William Jardine, Bart., LL.D., F.RB.S., F.R.S.E., ete., at Jardine Hall, Dumfriesshire, from January 1 to May 31, 1829. Trans, Dumfries. & Gall. Nat. Hist. & Ant. Soc. Vol. VI., pp. 88-124. —— Observations on Carrion-crows. Scot. Nat. Sept., p. 166. —— Hawfinch nesting in Dumfriesshire, loc. cit., p. 171. —— Albino Spotted Flycatcher, loc. cit. Nov., p. 195. E. H. Gopparp. Plans of Wiltshire Earthworks. Wilts. Arch. & Nat. Hist. Mag. 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July, p. 246. —— [Note on Martyn’s ‘ Figures of Non Descript. Shells ’], loc. cit. Aug., p. 279. H. M. Hatterr. Aculeate Hymenoptera in the Channel Islands. Znt. Mo. Mag. Nov., p. 262. W. Harimay. Naturein the Isle of Lewis. Animal World. Aug., pp. 91-92. S. H. Hamer (Secretary). The National Trust for Places of Historic Interest or Natural Beauty. Report, 1918-1919, 52 pp. A. H. Hamm. Observations on the Horse Bot-Fly, Gastrophilus equi, F. Ent. Mo. Mag. Oct., pp. 229-230. Soren Hansen. On Posthumous Deformation of Fossil Human Skulls. Man. Aug., pp. 121-124. See notice in Nat. Sept., pp. 283- 284. J. Rup@p Harprye. Willow-tit in Ross-shire. Brit. Birds. Dec., p. 195. —— Spotted Crake in Ross-shire, loc. cit., pp. 197-198. J. A. Harereaves. See W. E. L. Warram. EE2 420 NNO N N NN NONNN ND a] BZ oN v4 CORRESPONDING SOCIETIES. S. F. Harmer. Progress of the Natural History Museum. Nature. Dec. 4 p. 353. H. S. Harrison. The Ascent of Man: A Handbook to the Cases illustrating the Structure of Man and the Great Apes. Horniman Museum Handbook No. 13. 74 pp. JAmes M. Harrison. Iceland Gulls in the Orkneys. Brit. Birds. July, p. 62. —— Long-tailed Duck feeding on Grain [with note by F. C. R. Jourdain], loc. cit. Aug., pp. 85-86. J. W. H. Harrison. Stray Noteson Plants. Vasculum. . July, pp. 115-117. —— The Moth and the Candle, loc. cit. Dec., pp. 172-175. —— Studies in the Hybrid Bistoninae. III. The Stimulus of Heterozygosis. Journ. Genetics. Sept., pp. 259-265. IV. Concerning the Sex and related problems. Dec., pp. 1-38. —— A Preliminary Study of the effects of administering ethy] alcohol to the Lepidopterous insect Selenia bilunaria, with particular reference to the offspring, loc. cit., pp. 39-52. —— See R. S. BaGnatt. —— R.S. Bacnatn and J. E. Hunt. Notes and Records. Vasculwm. July, pp. 140-142. EB. Hartert. Serins in Sussex. Brit. Birds. June, p. 26. —— See W. J. WILLrAMs. Ernst Harrert. See H. F. 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Birds. July, pp. 40-41. —— Some points in the Sexual Habits of the Little Grebe, with a note on the occurrence of vocal duets in birds, loc. cit. Oct., pp. 155-158. A. D. Imms. Grain Pests and their Investigation. Nature. June 26, pp. 325-326. W. Ineuam. See W. E. L. Warram. CoLtiyawoop Ineram. Incubation during the laying period. Brit. Birds July, p. 64. —— Down Tracts in Nestling Birds, loc. cit., pp. 78-79. i bo N N NN ON N NNN N BNN N N NN ON ND BD DTD N NNNNNNNNN N N TT NN CORRESPONDING SOCIETIES. Grorrrey C. 8. Ingram. On the Breeding of the Lesser Redpole in Gla- morganshire. Brit. Birds. Oct., p. 136. J. J. The Fisheries and Scientific Research. Nature. July 17, pp. 385-386. A. B. Jackson and A. J. Witmorr. SBarbarea rivularis in Britain. Journ. Bot. Nov., pp. 304-306. Anniz C. Jackson. See H. F. WiruErsy. Dorotuy J. Jackson. Further Notes on Aphides collected principally in the Scottish Islands. Scot. Nat. Sept., pp. 157-165. J. Witrrip Jackson. The Bristly Millipede at Saltwick Bay, near Whitby. Nat. July, pp. 243-244. —— ‘Shell-Pockets’ on Sand-Dunes on the Wirral Coast, Cheshire ; and Notes on Ancient Land Surfaces. Lanc. & C. Nat. July, pp. 9-14, and Aug., pp. 39-44. —— andJ.G.Kircnen. Planorbis dilatatus and Physa heterostropha in the River Tame, at Dukinfield, Cheshire, loc. cit. Nov., pp. 131-132. A. W. Jamieson. Some Sussex implements. Proc. Prehist. Soc. E. Anglia. Vol. IIIL., pt. 1, pp. 108-110. T. A. Jerreries. Natural Transformations in the Vegetation of Blackstone Edge. Trans. Rochdale Lit. & Sci. Soc. Vol. XIII. pp. 18-24. GERTRUDE JEKYLL. Pollination of Viscum album. Journ. Bot. Oct., p. 286. H. C. Jippren-Fisuer. The Insects of East Grinstead District. Ent. Nov., . 256. T. J. J nie Swallows. Rep. and Trans. Devon Assoc. Vol. Ll., p. 63. J. W. HaicH Jonnson. Fungi [Report]. Ann. Rep.. Huddersfield. Nat. etc. Soc. 1918-1919, p. 19. —— See W. E. L. Warram. W. F. Jounson. Athous hirtus, Herbst, a correction. Jrish Nat. June, p. 80. —— Ploiariaculiciformisin Co. Armagh [with note by J. N. Halbert], loc. cit. July, p. 91. —— Rhyssa persuasoria in the counties of Down and Fermanagh, loc. cit. Oct., pp. 115-118. —— Entomological Notes for 1919, loc. cit. Nov., pp. 127-129. —— Irish Hymenoptera Aculeata in 1919, loc. cit. Nov., pp. 132-133. Water Jounson. The Jew’s Ear Fungus (Hirneola auricula-jude, Fr.). Nat. July, pp. 225-230; Aug., pp. 255-258; Sept., pp. 287-290 ; Oct., pp. 319-322. Jas. JoHNsTONE. The Dietetic Value of Sprats and other Clupeoid Fishes. Proc. and Trans. Liverp. Biol. Soc. Vol. XXXIII., pp. 106-133. —— The Probable Error of a Bacteriological Analysis, loc. cit., pp. 134-155. —— Pearl-like Concretions in Tripe, loc. cit., pp. 156-158. K. H. Jones and A. 8. Kennarp. Notes on the non-Marine Mollusca observed in East Ross and the Orkney and Shetland Islands. Proc. Malac. Soc. Oct., pp. 146-152. R. Jones. See W. KE. L. WArraAm. Ricuarp W. Jones. 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Parasitology. Oct., pp. 480-455. —— and G. H. F. Nurratyt. Hermaphroditism and other Abnormalities in Pediculus humanus, loc. cit., pp. 279-328. H. G. O. Kenpatn. Windmill Hill, Avebury, and Grime’s Graves, Cores and Choppers. Proc. Prehist. Soc. H. Anglia. Vol. IlI., pt. 1, pp. 104-108. A. 8. Kmnnarp. See K. H. Jonzs. —— and B. B. Woopwarp. Report on the Mollusca [Grime’s Graves], loc. cit., pp. 91-92. —— —— On Helix revelata, Britt. auctt. (non Férussac nec Michaud), and the validity of Bellamy’s name of Helix subvirescens in lieu of it for the British Molluse. Proc. Malac. Soc. Oct., pp. 133-136. —— —— On the Generic Names for the two British Ellobiide [Olim auri- culide|, Myosotis, Drapenaud (= Denticulatus, Montagu) and biden- tata, Montagu) loc. cit., pp. 136-139. Bart Kennepy. Insects Ihave met. Animal World. July, p. 79. —— My Window Sill [Birds], loc. cit. Dec., pp. 135-136. James H. Knys. Coleoptera at the Lizard, Cornwall. Ent. Mo. Mag. Nov., pp. 259-260. H. Kipner. Recent Discovery of an Unrecorded Type of Circular Earth- work in the New Forest [Abs.]. Man. Oct., p. 158. E. Botron Kine. EHuvanessa antiopa in Warwickshire. Ent. Nov., pp. 260-261. CHARLES Kirk. Great Spotted Woodpecker in Argyll. Scot. Nat. Nov., p- 185. —— Hawfinch in Dumbartonshire, Joc. cit., p. 194. D. J. Batrour Kirke. Nesting of the Pied Flycatcher and Garden Warbler in Ross-shire, loc. cit. : Mavup Krirxwoop. Black-tailed Godwits in Co. Mayo. Jrish Nat. Sept., . 108. J. G. Krrconen. See Annie Drxon. —— SeeJ. Witrrip Jackson. F. Lame. A Note on Four British Coccids. Ent. Mo. Mag. Oct., pp. 233- 234 —— Two species of British Aphides, loc. cit., Dec., pp. 272-274. —— Insects damaging lead, loc. cit., pp. 278-279. W. D. Lana. Old Age and Extinction in Fossils. Proc. Geol. Assoc. Vol. XXX., pt. 01, pp. 102-113. KE. Ray Lanxester. The Foundation of Biological Sciences. Nature. Nov. 6, pp. 198-201. J. Larprr. Size of specimens of Acer campestre. Nat. Nov., p. 372. C. E. Larter. Hypericum humifusum. Journ. Bot. Oct., p. 287. Wm. S. Lavzrock. Presidential Address. [‘ The Collecting of Flowering Plants and Ferns and the Making of a Herbarium.’] Proc. Liverp. Nat. F. Club. for 1918, pp. 10-19. —— KE. Rem, Rosr Earrtron. The Field Meetings of 1918 [Report], loc. cit., pp. 20-37. A. K. Lawson. Vitrea and Pyramidula Destroyed by Ants. Jowrn. Conch. Aug., p. 127. Nina F. Layarp, The Mundford Pebble Industry. Proc. Prehist. Soc. E. Anglia. Vol. TIL, pt. 1, pp. 150-157. —— Flint Tools showing well-defined finger-grips. Proc. Suffolk Inst. Arch. & Nat Hist. Vol. XVII. pt. 1, pp. 1-12. —— Remains of a Fossil Lion at Ipswich. Nature. Dec. 25, p. 413. W. Luacn. Manchester Microscopical Society [Reports]. Lanc. & C. Nat. Nov., p. 133. —— See Anniz Drxon. Marie V. Lesour. Feeding Habits of Some Young Fish. Journ. Marine Biol. Assoc. July, pp. 9-21. —— The Food of Post-Larval Fish, loc. cit., pp. 22-47 424 NNDB © BOO N N 7 NN N @7 NN N NNNNNNNNNNNND BN NN NNN WN uv NN CORRESPONDING SOCIETIES. Marie V. Lrzour. The Young of the Gobiide from the Neighbourhood of | Plymouth, doc. cit., pp. 48-80. —— Further Notes on the Young] Gobiide from the Neighbourhood of Plymouth, loc. cit., pp. 146-148. A. Luz. See E. Warnurst. Joun R. Ler. Some Clydesdale Sphagna. Glasgow Nat. Sept., pp. 71-72. F. Arnotp Less. The Nightmare of Names in the bed of Roses. Nat. June, pp. 211-213. —— Cypripedium Calceolus: Earliest Record, loc. cit. Oct., p. 341; also Dec., p. 399. —— The Distribution of Gentiana verna, loc. cit: Dec., pp. 390-391. H. Maxwewt Lerroy. See K. M. Smiru. W. Haroip Leicu-Suarrr, The Genus Lernaeopoda. Including a description of L. mustelicola n.sp., remarks on L. galei and further observations on L. scyllicola. Parasitology. Oct., pp. 256-266. G. B.C. Lemon. Silpha atrata L., with Abnormal Antenne. Ent. Rec. Oct., ; p: 185. —— Notes on Coccinellidae, loc. cit., pp 213-214. H. Masen Lewis. See W. A. HerpMan. Srantey Lewis. Introduction of Red Grouse into Somerset. Brit. Birds. Aug., p. 86. —— Rock-Dove absent from Cheddar Cliffs, Joc. eit., p. 111. T. Lewis. Young Buzzard takes a Shower-bath. Brit, Birds. Oct., pp. 140- 141. L. Linzetu. See A. Bacor. GutietmMa Listrr. A Three-spurred form of the Larger Butterfly Orchis (Habenaria chlorantha Bab. var. tricalcarata Helmsley). Essex Nat. Vol. XIX., pt. 1, p. 22. —— Mycetozoa found during the Selby Foray. Trans. Brit. Mycol. Soc. Sept., pp. 88-91. . J.E.Lirtie. Notes on Bedfordshire Plants. Journ. Bot. Nov.,pp. 306-312. S. H. Lone. Osprey in the Norfolk Broads. Brit. Birds. July, p. 58. W. ArtHuR Lona. Catocala nupia ob. Ent. Nov., p. 261. C. B. Lown. See W. D. W. GrEeEnHAm. Lewis R. W. Loyp. Little Owl in South Devon. Brit. Birds. Nov., p. 164. W.J.Lucas. Noteson British Orthoptera in1918.. Hnt. Aug., pp. 171-174. —— Agriades corydon in the New Forest, loc. cit. Oct., p. 237. —— Pararge megera, Linn., loc. cit. —— Vespa crabro, loc. cit., p. 239. —— Orthoptera in Captivity, loc. cit. Nov., pp. 249-250. —— Preserving Orthoptera, Joc. cit., pp. 250-252. —— Dorset Orthoptera, loc. cit. Dec., p. 280. —— The Odonata of the Lancashire and Cheshire District, Lanc. & C. Nat. Aug., pp. 55-60. G. T. Lyte. Contributions to our knowledge of the British Braconide. Ent. June, pp. 134-136; July, pp. 149-155; Aug., pp. 178-181. D. Macponaup. Wigeon nesting in Ross-shire. Scot. Nat. Sept., p. 171. —— The Whooper Swan in Ross-shire in June, loc. cit., Nov., p. 196. —— Whooper in Ross-shire in June. Brit. Birds. Oct., p. 141. CaarteEs McIntosx. Note on a Stone Cist found at Dalguise. Zrans. Perth Soc. Nat. Sci. Vol. VI., pt. v., p. 206. [W. C.] M‘Intosu. The Fisheries and the International Council. Nature. July 3, pp. 355-358 ; July 10, pp. 376-378. —— Sea-Fishery Investigations and the Balanceof Life, loc. cit., Sept. 18, p. 49. T. ToHornton Mackeitu. The Nightjar in Renfrewshire. Scot. Nat. Sept., p. 166. THomas McLaren. Note on a Stone Cist found at Kildinny, near Forteviot, November, 1917.. Trans.- Perth. Soc. Nat. Sci. Vol, VI., pt. v.; pp. 201-203. —— Bronze Age Burial Urns and other Remains found at Sheriffton, near Scone, December, 1917, loc. cit., pp. 203-205. M. C. McLeop. Catocala fraxini [near Eastcote]. Ent. Aug., p. 189. -—--- Colias edusa in Surrey., loc. cit., Oct., p. 235. NNN NNN N N © DVoUYNNNNN NN NONDD © DN DN ND NNN ao NN N ONN LIST OF PAPERS, JUNE—DECEMBER, 1919. 425 A. Honre Macrnerson. Wild Hybrid between House-sparrow and Tree- sparrow. Brit. Birds. Dec., p. 199. Wm. Percy Mam. Haunts of the Black-headed Gull. Vasculum. July, pp. 97-101. G. W. Mazcorm. Unusual Nesting-place of Grey Wagtail. Scot. Nat. Nov., p. 195. M. Matone. See W. E. L. Watram. Wm. Manssriver. Lancashire and Cheshire Entomological Society |Report]. Ent., June, p. 144; Lanes. & Ches. Nat. July, pp. 26-27. —— Lepidoptera. Report of the Recorder for 1918. Lanc. & C. Nat. Aug., p. 44-47, R. R. pi es Recent Archeological Discoveries in the Channel Islands.— (1) La Cotte de St. Brelade [Abs.]. Man. Oct., p. 157. A. W. Marriage. Multiple Nests of Blackbird. Brit. Birds. Sept., pp. 108- 109, J. G. Marspren. Cone Cultures at the Land’s End. Proc. Prehist. Soc. £. Anglia, Vol. IIL, pt. 1., pp. 59-66. E. 8. Marswarni. Notes on Somerset Plants for 1918. Journ. Bot. June, pp. 147-154; July, pp. 175-181. —— Barbarea rivularis in England, loc. cit., Aug., pp. 211-212. —— Verbascum thapsiforme as a British Plant, loc. cit., Sept., pp. 257-258. James M‘L, Marswaun. Woodcock and Young, Scot. Nat. Nov., p. 198. F. A. Mason. See W. E. L. Wartram. G. W. Mason. Entomology. [Report.] Zvans. Lincs. Nat. Union for 1918, p. 113. W. W. Mason. Jackdaw’s Unusual Nesting Site. Nat. Oct., p. 318. Hersert Massey. J. J. Lister on Hodgkinson’s Record of P. egon in Tutt’s ** british Butterflies.” Hnt. June, p. 137. —— Late Third Brood of Swallows. Brit. Birds. Nov., p. 161. —— Weights of Cuckoos’ Eggs, loc. cit., Dec., p. 198. GERVASE F. Matnew. Notes on Butterflies. Hnt. Oct., pp. 227-228. —— Cherocampa nervi at Dovercourt, loc. cit., p. 237. —— Issoria (Argynnis) lathonia and Colias edusa at Folkestone and Dover, loc. cit. Nov., pp. 259-260. J. L. Maxim. Discovery of a Bloomery at Birches, Healey. Trans. Rochdale Lit. & Sci. Soc. Vol. XIII, pp. 94-99. —— Querns and other Corn-grinding Stones recently found in the Rochdale District, loc. cit., pp. 100-102. E. Ketty Maxweitt. The Amateur Microscopist during Wartime. Journ. Quekztt Micro. Club. No. 85, pp. 63-72. Hersert Maxwetu. Antlers. Trans. Dumfries. & Gall. Nat. Hist. & Ant. Soc. Vol. VI., pp. 12-21. A. Mayatt. Abnormal Clutches of Chaffinch’s Eggs. With note by F. C. RB. Jourdain. Brit. Birds. Aug., pp. 80-81. C. M. Mayor. Colias edusa var. pallida (helice). Ent. Nov., p. 260. —— _ Enugonia polychloros in Devon, loc. cit., p. 261. D. H. Mrargs. Great Crested Grebes nesting in Kent. Brit. Birds. July, pp- 5 and 60. W.S. Mepricorr. Wood-Lark in North Lincolnshire, loc. cit. June, p. 26. —— _ Goshawk in Lincolnshire, loc. cit. Nov., p. 164. R. MrmNertTzHAGEN. __ an bine INDEX. Wnuitaker (J.), Excavations at Motya, N.-W. Sicily, *368, +382. WuHiItTakER (W.), Status of local societies, *404. Wuirrnnap (T.), Parasitic fungi of N. Wales, *379. WisBERLEY (Prof. T.), Experiments in intensive corn-growing, *380, +383. Wuu1aMs (Prof. J. Lloyd), Alternation of generations in Laminariacez, *372. in discussion on soil and plant survey work, *374. Welsh traditional music, *369. Wutsurre (8. P.), Infection of apple trees by Nectria ditissima, Tul., *379. Wopeuouse (Miss H. M.), Training col- leges in national system of education, 378, $383. NP nee, 1920 AL HisT® 445 Woopwarp (Prof. A. M.), Excavations on a hill fort at Ilkley, *366. Wool industry, psychological skill in, by H. Binns, *371, 382. Woorton (Mrs.), Future of earning, 363. Word-blindness in the mentally defective, by Miss L. C. Fildes, *370. Wortnam (Miss W. H.), Vegetation of Anglesey and N. Carnarvonshire . . 373. Wvyarrt (8.), Psychology of industrial life «ina POUL, F382. =3, Zine, electrolytic, by S. Field, *353. Zoological Section: Address by Prof. J. Stanley Gardiner, 87. 4 4/ oY ‘Serres PAB 6g fucks» rte noe «yall ent PSBG. olauts ; hens tient wets ia ai gp a ie 14 5 Ee aes TH Omal silt yd EBET io Wie apilf) og saree Sys ametnen eb ofa sn je a Surpeyreg, vegray arnt oad 4 a ie hopfh a ney 4) iq: $ap oS oti Lapwtet bre to Epi | Te* - Coeptre of io efsira! RT SY ter veein 208" lena fecoitib ? rapaad temedrch do dhe cocences “h, ty olqqe to sottoctel hyd. Dr. BB Griiitite ard Moise & | Bree lo vedi sabia i -BRS4, biaea, we Pliviottosia rs Sv horFe ye venbbhed sivotnAceyoBe | 00 K ta St: apie Thiru) yolante, 7 : : Taxtok 1H. V4, Dhsttibotion eee in putatoon, *7FR. § Teachers, eayply ot, boy &. + Terrdetcatanagn tise, acer Girbaste; and re bet Pri. &: lhe pone, 7 Tn Testing ~materials at sh Hh), cnet ‘ef ' *55 2. ‘ by Pot. 7, Lea. ees: rise { “ Tims 31th Edowfne), Coss “yt teth hand L gepinet 4 Enotes i of dimitibetjon of poppin Qaee 1h eet, “OG = Weles aoalinll, 306,733) Erergy. “al Fos einans | F iglaeh inks Pea oe tir. Rtay) be dine on it - tiene acd by eet pohor : eG plent netvey work, “Al 4 ; "3.0 } Terao ae. Campleity,. Barhest tu. rom Dinait, cloctrigatya ® : Sobliagin ct Ralyierbie-*gge, yas. Waive 4e %.), 7 Temes (Pete a Dk the chine. 3... MN. Wales, hacriom. teela meses pase’: a Etiey * ¥ shan, 6-7 , oe “S78, t75i. uneiey.” * 352, i ee T dal. inatiinte ot Lawweper® Asner? |o, | MARE: 40) 5, ee ¥ Cemom hee, tin, SY. ; ; bi Bape o> etka i ae Titpesiax..Gdie Ma ti), Profiniceny, i Wairtate ered, Ww: “e notes on. Burings: sxall) “Site, 2381 , - 2hetn { Rie eneey Kitten: 4 Teed DD RB. Pye. Seecido | peasteros, “365. F381," Se teat eid diktacmiion is ijtertal-com- | Wares (6, Probinamdbyer hyiwet tesa, engronsts, PSGd. REL : thom, “Sit. t Rae”, Piaare ft, 3, te disnunhow as ipbrigs« |. Ween’ (PRA ‘Ber, . thou, *RRS 1 o~ ame TU somah ign Pb debe rr Peola, Garett, Phil. Mag., 6, 374 (1903). 26 Harnack, Zeit. Physikal Chem., 26, 571 (1899). 27 Thnen, J. Soc. Ch. Ind., 504, (1905). 28 Jager, Chem. Abs., 10, 551 (1916). 29 Kremann, J. C. S. (i), 544 (1919). 30 Langer, Zeit. Brauwesen, 27, 307 (1904); J.uS.C.J. 555 (1904). $1 Langer & Schultze, Zeit. Brams., 2, 369 (1879); 6, 329 (1883). 32 Lamplough, Rig Camb. Phil. Soc., 14, 591 (1908). 38 Lefebure, J. C. Trans. 332 (1914). 34 Luther & Mdacoukall J. C.'S., ii., 361 (1908). %> Luther & Kasnjavi, Zeit. Physikel Chem. 46, 170 (1905). 36 Mare, Zeit. F. Chem. Ind. Koll., 14, 181. 37 Menz., Zeit. Physikel Chem., 66, 129 (1909). shold Meyer, Zeit f. Elektroch., 241 (1909) 89 Mohr, Woch f. Brau., 363 (1904). 40 Muller, Wied Ann, 87, 24 (1889). 41H, Miller, J. C. S., 23, 37 (1870). 48 42 Nernst, Zeil. Physikal Chem., 52 (1904). 43 Patten & Mains, J. Ind. Eng. Chem., 10, 279 (1918) 44 Peters, Jour. Physiol. 44, 131 (1912). 45 Perman, J. C. S., 67, 868, (1895); 73, 511 (1898). 46 Prior, J. Soc. C. Ind., 288 (1899). . 47 Roth, Zeit. Hlektroch. (15), 328 (1909). 48 Ritzell, Zeit Physikal Chem., 60, 319 (1907). 49 Sander, Zeit. Physikal Chem (1912). 50 Sackur & Stern, Zeit. Hlektroch., 18, 641 (1912). 51 yon Schroeder, Zeit. Physikal Chem., 45, 75 (19038). 52 Siegfried, Zeit. Physiol. Chem., 44, 451 (1905). 53 Smith, J. Am. Ch. Soc., 41, 145 (1919). 54 Steele, J. C. S., 88, 1470 (1903). 55 Stern, Zeit. Physikal Chem., 71, 468 (1912). 56 Stocks, First Report on Coll. Chemy. Brit. Assn., 73 (1917). *7 Swanson & Hulett, J. Am. Chem. Soc., 37, 2490 (1915). °8 Trautz, Zeit. Anor. Chem., 106, 149 (1919); J. C. S., 137 (1919). °9 Tissot, Compt. Rend., 158, 1923 (1914). 60 Usher, J. C. S. Trans , 97, 73 (1916). 61 Van Bemmelen, Zeit. f. Anor. Chem., 18, 233 (1897). 62 Veley, Phil. Trans., 275 (1888); Phil. Mag., 209 (1903). 638 Wellstattér & Stoll, Ber., 50, 1791 (1917). 64 Wolman & Emslow, Ind. Eng. Chem., 209 (1919). 65 Young, J. Am. Chem. Soc., 38, 48-1375 (1911). 66 Zseigmondy & Spear, Chemistry of Colloids, p. 147 (1917). THE ELECTRICAL CHARGE ON COLLOIDS. By Joun Antuur Witson, Chief Chemist, A. FP. Gallun & Sons Co., Milwaukee. The origin of the electrical charge on colloids is still a matter of uncertainty, although it is possible that the charges may not always arise from the same cause. It has been common practice for writers to shelve the question by assuming that a sufficiently satisfactory answer is given by Coehn’s empirical law that ‘‘ a substance of higher dielectric constant charges itself positively when it comes in contact with a substance of smaller dielectric constant.” Even if the state- ment of this law were true, it would not constitute an explanation since it tells nothing regarding the manner of bringing about the charging. Taylor has suggested the possibility of the charge arising from the colloid surface being more impermeable to certain ions than to others. He found that a membrane of aluminum hydroxide is formed by the interaction of aluminum salts and ammonia which is permeable to hydrion, but impermeable to hydroxidion, even a large E.M.F. failing to drive hydroxide ions across such a film. Thus, when alumina is suspended in water, the hydrion dissolves in or diffuses into it, leaving the hydroxidion at the surface, and the particles become positively charged. This will also explain the alteration of the charge on albumen by acids and alkalis, if it may be assumed that hydrogen and hydroxide ions are equally soluble (or diffusible) in albumen. In such.a case the concentration of either ion in the albumen would vary directly as its concentration in the solution This explains why albumen possesses no charge in neutral solution 49 and why the positive charge increases with increasing acidity and the negative charge with increasing alkalinity, However, Taylor admits that these explanations are not necessarily correct, because they fit the facts and even suggests that adsorption, rather than differential diffusion, is responsible for the charge. The great majority of opinion regarding the origin of the charge seems to be included in the following possibilities; that the charge results from the selective adsorption of ions at the surface of the colloid; that it is due to the ionization of foreign substances incor- porated in the surface of the particles; or to the ionization of the colloid itself. In his recent book, Burton gives an interesting discussion of the subject. In hydrosols of the oxidizable metals, the particles are positively charged, while in hydrosols of the non-oxidizable metals, the particles are negatively charged. Hardy explained this on the assumption that the charge is due to a reaction between the metal and water at the moment of formation of the hydrosol. In the case of the oxidizable metals, ionizable hydroxides are formed; in the case of the non-oxidizable metals, ionizable hydrides. The particles, however, are so comparatively large that the greater portion of the metal compound has the properties of matter in mass and ionization takes place only at the surface of the particles. Burton has confirmed this view by experiments with methyl and ethyl alcohols, which have easily replaceable OH groups. He was unsuccessful in repeated attempts to prepare alcosols of platinum, silver, and gold, but succeeded in preparing alcosols of the oxidizable metals. On the other hand, when platinum, gold, and silver wires were sparked under ethyl malonate, which has a replaceable hydrogen, very stable sols were obtained, in which the particles were negatively charged; but sols of the oxidizable metals could not be obtained with ethyl malonate. Burton’s own view is that the charges on the particles are due, in the case of the Bredig metal sols, to the ionization of a layer of hydroxide or hydride on the surface of the particles. Duclaux believes that the charge always arises from the dissociation of a portion of extraneous substance retained by the particles from the reacting media and he has shown that there is always a trace of FeCl, in Fe(OH)? sols. Zsigmondy admits that in special cases the charge is due to the ionization of the colloid itself, for example, where an ionizable substance has molecules so large as to give it the properties of a colloid. He objects to the idea of the formation of chemical compounds in all cases on the ground that it would entail “ the inclusion in the category of chemical compounds of a large number of badly defined bodies, and load chemistry with much useless ballast.”’ He prefers explaining such reactions on the basis of adsorption of ions. The acceptance of Langmuir’s explanation of adsorption as a chemical phenomenon would reduce Zsigmondy’s objection to one of terminology. Among the more recent papers dealing with colloidal metallic hydroxides may be mentioned that of Pauli and Matula, who confirm Duclaux’s belief concerning colloidal Fe(OH);. Kimura regards the charge as due to simple ionization of the hydroxide, the extent of which is determined by a balancing of the forces causing ionization a 11454 D 50 and the attractive forces acting between the positively charged particles and the hydroxide ions. But Powis produced negatively charged colloidal ferric hydroxide by adding a sol of the common type to a dilute solution of sodium hydroxide. He considered the change in sign of the charge to be due to the adsorption of hydroxidion. No reliable method has yet been devised for determining the absolute value of the electrical charge on a colloidal particle. From Burton’s data, Lewis made an extremely rough calculation of 8 x 10° electrostatic units for a platinum particle. Powis calculated a value of about 2 x 10~ for a coarse silver particle. Upon the assumption of the existence of the Helmholtz double-layer at the surface of colloidal particles, the difference of potential between the disperse phase and the medium has been calculated. The voltages found lie almost entirely between — 0-07 and + 0-07. The results of Ellis and of Powis for oil emulsions indicate that for a stable emulsion the absolute value of this voltage must be greater than 0-03. Between the values — 0-03 and + 0-03, complete coagulation occurs, but at a velocity apparently independent of the voltage. Wilson has shown that the electrical charge on the surface of colloidal particle must cause an unequal distribution of ions between the surface layer of solution surrounding the particles and the bulk of solution, which would, in turn, result in a difference of potential between the two phases. A very important conclusion of this work is that the addition of an electrolyte to a sol, provided no chemical changes follow, must result in a lowering of the absolute value for the potential difference between the two phases, even though there may be no change in the magnitude of the electrical charge on the colloid itself. This is considered to be the explanation of the precipitation of suspensoids by addition of salt. This subject is so closely allied to that of electrical endosmose that the report compiled by Briggs (Second Report, p. 26) should be consulted. BIBLIOGRAPHY. Erans, H. T., and Easriack, H. E. ‘The Electrical Synthesis of Colloids ‘J. Am. Chem. Soc.,’ 87, 2667 (1915). Burton, E. F. ‘The Physical Properties of Colloidal Solutions’ (Longmans, Green & Co.). Exuis, R. ‘Properties of Oil Emulsions’: I Electric Charge; ‘Z. Physik. Chem.’ 78, 321. II. Stability and Size of the Globules, ibid., 80, 597. III. Coagulation by Means of Colloidal Solutions, ibid., 89, 145 (1914). FRENKEL, J. ‘The Surface Electric Double-Layer of Solid and Liquid Bodies.’ ‘Phil. Mag.’ 38, 297 (1917). GurxE.ut, 8. ‘ The Electrical Transference of Gels.’ ‘ Kolloid-Z.’ 18, 194. Harpy, W. B., and Harvey, H. W. ‘Surface Electric Charge of Living Cells.’ Proc. Royal Soc.’ London, 84, 217, Harpy, W. B. ‘ Differences in Electrical Potential within the Living Cell.’ ‘J. Physiol.’ 47, 108, von Hrvesy, G. ‘The Charge and Dimensions of Ions and Dispersoids,’ * Kolloid-Z.’ 21, 129 (1917). : Kimura, M. ‘ Nature of the Double Layer in Colloidal Particles,’ I * Memoirs Coll. Science,’ and ‘ Eng. Kyoto Imp. Univ.’, 5, 201. 51 Krouyt, H. R. ‘Current-Potential of Electrolytic Solutions.’ ‘ Verslag. Akad, Wetenschappen,’ 238, 252 (1914). ‘ Electrical Charges and the Limiting Values for Colloids,’ ibid., 28, 260 1914). : ‘Current Potentials and Colloid Stability.’ ‘ Kolloid-Z.’, 22, 81 (1918). Lewis, W.C.McC. ‘ A System of Physical Chemistry.’ (Longmans, Green & Co.) Pavui, W., and Maruna, J. ‘A Physicochemical Analysis of Colloidal Ferric Hydroxide.’ ‘ Kolloid-Z.’ 21, 49 (1917). Powis, F. ‘The Relation between the Stability of an Oil Emulsion and the Potential Difference at the Oil-Water Surface Boundary and the Coagulation of Colloidal Suspensions.’ ‘ Z. physik. Chem.’ 89, 186 (1914). ‘The Influence of Time on the Potential Difference at the Surface of Oil Particles Suspended in Water,’ Jbid., 89, 179 (1914). ‘ Negative Colloidal Ferric Hydroxide.’ ‘ J. Chem. Soe.’ 107, 818 (1915). * Transference of Electricity by Colloidal Particles.’ ‘ Trans. Faraday Soe.’, (1915). ‘The Coagulation of Colloidal Arsenious Sulfide by Electrolytes and its Relation to the Potential Difference at the Surface of the Particles.’ ‘J. Chem. Soe,’. 109, 734 (1916). Snorter, S. A. ‘The Capillary Layer as the Seat of Chemical Reactions.’ ‘J. Soe. Dyers & Colourists,’ 84, 136 (1918). Taytor, W. W. ‘The Chemistry of Colloids’ (Longmans, Green & Co.). Tuomas, A. W., and Gararp, I. D. ‘The Fallacy of Determining Electrical Charge of Colloids by Capillarity.’ ‘J. Am. Chem. Soc.’ 40, 101 (1918). Witson, J. A. ‘Theory of Colloids.’ ‘J. Am. Chem. Soc.’ 38, 1982 (1916). ZstemonDy, R. ‘ Theoretical and Applied Colloid Chemistry.’ (John Wiley & Sons. 1917 ) IMBIBITION OF GELS—PART I. By Joun Artuur Witson, Chief Chemist, A. F. Gallun & Sons Co., Milwaukee. One of the commonest methods of demonstrating what is meant by imbibition is to immerse a thin sheet of ordinary gelatin in water. In less than an hour the gelatin will be found to have become mutch swollen by absorbing, or imbibing water. After the first hour, the rate of swelling noticeably decreases, and the volume papers to approach a definite limit. The amount of water taken up can be determined by weighing the gelatin before and after swelling. The absorbed water behaves much as though it were dissolved in the gelatin, and it can be removed by washing the gelatin with absolute alcohol. As the water is removed, the volume of the gelatin diminishes, approaching its volume before swelling. During imbibition heat is evolved, which has often been referred to as heat of swelling. Probably this is responsible for the repeated statement that the application of heat will repress the swelling of gels. On the contrary rise of temperature causes greater swelling, which seems to indicate that the liberation of heat is not due to swelling, but to some other cause, which the writer believes to be chemical combination between the gelatin and a small portion of the absorbed water. Procter has shown that the degree of swelling is also dependent upon the previous history ot the gelatin. He prepared three solutions containing 5 per cent., 10 per cent., and 20 per cent. respectively of gelatin and allowed them to set. He then dried the jellies and, after weighing, allowed them to soak in water for seven days. The sample with the D2 52 greatest volume at time of setting absorbed 14-6 times its weight of water, the second sample, 7-7; and the sample with smallest setting volume only 5:8 times its weight of water. Gelatin swells to a much greater extent in dilute acid solutions than in water. The parts of solution absorbed by one part of a certain sample of gelatin, at 18°, were in pure water 8, in 0-006 N HCl 42, in 0:05 N HCl 28, in 0-3 N HCl only 17. Stronger solutions of the acid caused the gelatin to soften and finally dissolve. This action appears to be independent of the swelling phenomenon, and at higher temperatures becomes more marked, even with lesser concentrations of acid. By plotting the amount of swelling against the concentration of acid up to 0:3 N, a curve with a maximum is obtained, the explanation of which has given rise to several theories, which will be treated later. The most extensive investigation of the hydrochloric acid gelatin equilibrium seems to have been made by Procter, who showed that the concentration of free acid is always less in the solution absorbed by the gelatin than in the remaining external solution, and that the sum of the amounts of free acid in both these solutions is less than the amount in the solution before the introduction of the gelatin. He attributes this difference to chemical combination between the gelatin and some of the acid and regards the product as a hydrolyzable, but highly ionizable chloride of gelatin. This agrees with the electro- metric determinations of Manabe and Matula, who found that in certain hydrochloric acid solutions of gelatin nearly all hydrogen ions were bound by the protein and nearly all chloride ions were free. They examined acid solutions of serum albumin similarly and regarded the behaviour of both proteins as that of weak bases forming hydrolyzable salts. Gelatin swells likewise in solutions of other acids, but not to the same extent as in HCl, nor does the point of maximum occur at exactly the same concentration of either total acid or hydrogen ion. With strong acids the maximum in the swelling curve is very pronounced, becoming less so with weaker acids, With acetic acid the maximum is hardly reached at concentrations so great as to cause solution of the gelatin. Extremely weak acids like boric produe very little swelling. If sodium chloride, or other neutral salt, be added to acid- swollen gelatin, the latter contracts and gives up the solution it had absorbed to an extent depending upon the concentration of added salt. If the solution be saturated with salt, the gelatin shrinks to a horny mass. Fischer found that even non-electrolytes, such as sugars, produce this repression of swelling, although not nearly to the same extent as salts. Repression is produced by the acid itself when present in concentrations greater than that required to produce maximum swelling. Experiments dealing with the swelling of gelatin in alkalis are generally not so satisfactory as those with acids, because of the more powerful solvent action of alkalis on the swollen gelatin. Nevertheless, by using only very dilute solutions at low temperatures, sufficient data have been collected to show that alkaline swelling is of the same 53 general nature as acid swelling. The swelling increases with increasing concentration of alkali to a maximum and then falls until such concentration is reached that the gelatin softens and dissolves. Swelling is repressed, here too, by addition of neutral salts. While neutral salts are capable of repressing the swelling of gelatin in acids and alkalis, it must not be overlooked that they are also capable of producing swelling. Procter found that, with increasing concentrations of sodium chloride, gelatin swells to a maximum and then contracts steadily until the solution is saturated. The swelling was not so marked as in the case of acids, however, the gelatin taking up a maximum of only about 17 times its weight of water as compared to three times this amount with HCl. He also noted that the gelatin removes some of the salt from solution, suggesting combination, but that the addition of HCl again liberates this salt and causes the salt to become more concentrated in the external solution than in the solution absorbed. Loeb has done some work on neutral salts that should be mentioned _here. In each of aseries of experiments he placed two grams of finely powdered gelatin into a cylindrical funnel, the powder being held in the cylinder by a circular piece of filter paper. One sample was perfused six times in succession with 25 cc. of distilled water and the amount of swelling noted, which was taken as the height in millimetres to which the gelatin rose in the cylinder; this sample was taken as the standard. Another sample was perfused twice with 25 c.c. of M/8 NaCl, and then four times with 25 c.c. of distilled water ; the swelling here was several hundred per cent. greater than that of the standard. Still another sample was perfused six times in succession with 25 c.c. of M/8 NaCl; it did not swell to any greater extent than the standard. Loeb attributes these results to a chemical combination between the gelatin and salt, a highly ionizable sodium gelatinate being formed. In the third experiment, much swelling _ was prevented by the excess of salt present; when this was washed away, as in the second experiment, the gelatin swelled to a much greater extent than in pure water. He confirmed this view by showing that, when placed in an electric field, gelatin which has been treated with NaCl migrates to the anode. A sample first perfused with calcium chloride solution and then with distilled water showed very little more swelling than the standard. He accounts for this by saying that the calcium gelatinate formed is only very slightly ionizable. Collagen, fibrin, and other proteins behave much like gelatin when immersed in solutions of acids, alkalis, or salts, and are probably subject to the same general laws. Other examples of imbibition are the swelling of agar-agar, gums, and cellulose in water and the swelling of rubber in organic solvents. It would take volumes to mention all of the work done on this subject. Numerous attempts have been made to explain the molecular mechanism of imbibition, particular attention being paid to the explanation of the peculiar swelling curve. Most of these, however, have been guilty of drawing largely upon the imagination for some- thing that would agree qualitatively with the experimental data 54 without regard for lack of grounds for the assumptions involved, Several of these still survive because, while they cannot be proved, they are not of a nature to be easily disproved. It will probably be sufficient to outline two of the more recent ones. Perhaps it would be unfair to consider Fischer’s theory of imbibition as attempting to give an explanation of the molecular mechanism of the phenomenon. He regards gelatin as a substance capable of existing in different degrees of association or polymerisation; in other words, the particles of gelatin may vary greatly in size, dependent upon conditions to which they are subjected. Thus rise of tempera- ture or increase in concentration of acid or alkali, causes the particles to become smaller in size, the change being reversible. The particles are assumed to be capable of becoming most heavily hydrated, that is, of absorbing most water, when they have a medium diameter. The particles of neutral gelatin are large and capable of absorbing comparatively little water. Increasing the concentration of acid decreases the size of the particles, making them capable of absorbing more water, and the gelatin swells until the size of particle most - readily hydrated is reached. As the particles become still smaller, the swelling becomes:less until finally the particles become so small that the gelatin apparently goes into solution. The theory of Tolman and Stearn assumes that, because of their amphoteric nature, protein colloids have marked tendencies to adsorb hydrion from acid solutions and hydroxidion from alkaline ones. In a solution of a strong acid, the adsorbed hydrogen ions, together with a corresponding number of anions, form a “ double layer’ on the walls of the pockets or pores in the interior of the gel, and this leads to swelling and imbibition of water by electrostatic repulsion. The addition of neutral salt or excess of strong acid to such a swollen colloid will furnish ions in the interior of the pockets which will tend to arrange themselves so as to neutralise the electrical fields of the adsorbed layer and thus being about a reduction of the swelling. The addition of a neutral salt to the acid solution tends to neutralise the electrical field of the adsorbed acid, making it easier for more acid to get to the surface of the pockets, thus leading to increased adsorption. Polyvalent ions are more effective than univalent ions in reducing swelling because, while taking up no more room than univalent ions, they are twice as eleeeve in neutralising an. existing electrical field. In contrast to these stands the theory saat by Procter and developed by him in collaboration with his pupils. By very extensive investigations with gelatin and aqueous solutions of acids and salts, he succeeded in finding quantitative relationships between several of the variable factors involved. Once a foothold was gained in the form of an equation, it was found possible to make big advances merely by an application of mathematics. Procter built up his theory from experimental data; more recently J. A. and W. H. Wilson worked in the opposite direction by purely mathematical reasoning from the assumption of the existence of a certain hypothetical substance and calculated what results Procter should have found experimentally. terete, 55 All of their calculated curves coincided completely with Proctor’s experimental ones, and for this reason the writer considers the essential part of the theory as proved. The importance of the subject warrants our giving a review of the mathematical deductions, which include an adequate explanation of Procter’s theory. Consider the purely hypothetical substance G which is a colloid jelly completely permeable to water and all dissolved electrolytes, is elastic and under all conditions under consideration follows Hooke’s law, and which combines chemically with the positive, but not the negative ion of the electrolyte MN, according to the equation— [@] x [M+] = K[GM*] (1) In other words, the compound GMN is completely ionized into GM~*+ and N-. The brackets indicate that concentration is meant and all concentrations are in moles per litré. The electrolyte MN is also considered totally ionized. Now take one millimole of G and immerse it in an aqueous solution of MN. The solution penetrates G, which thereupon combines with some of the positive ions, removing them from solution, and conse- quently the solution within the jelly will have a greater concentration of N- than of M+, while in the external solution [+] is necessarily equalto[N~]. The solution thus becomes separated into two phases, that within and that surrounding the jelly, and the ions of one phase must finally reach equilibrium with those of the other phase. At equilibrium,+in the external solution, let— MF iL] and in the jelly phase let-— y= [M*] and— e=— (Gs | whence— [N-]=y+z. The relation existing between the concentrations of diffusible ions of the two phases at equilibrium can be derived from the consideration of the transfer of an infinitesimally small amount, dn moles, of Mt and N~ from the outer solution to the jelly phase, in which case, since no work is done— dnRT log x/y + dnRT log x/(y + z) = 0, whence— a? = yy + 2). (2) But in this equation, the product of equals is equated to the product of wnequals, from which it follows that the sum of those unequals is greater than the sum of the equals, or— 2y + 2 > 2a. This is a mathematical proof that the concentration of diffusible ions of the jelly phase is greater than that of the external solution, and makes possible the derivation of a second equation involving e, 56 which is defined as the excess of concentration of diffusible ions of the jelly phase over that of the external solution— 2e + e= 2y+z. (3) Since [V~-] is greater in the jelly than in the surrounding solution, the negative ions of the colloid compound will tend to diffuse outward into the external solution, but this they cannot do without dragging their colloid cations with them. On the other hand, the cohesive forces of the elastic jelly will resist this outward pull, the quantitative measure of which is e, and according to Hooke’s law— e— CV. (4) where C is a constant and V the increase in volume in cubic centi- meters of one millimole of the colloid. Now, since we have taken unit quantity of the substance G— [G] + [4M +] = 1/(V+ a) [G] = 1/(V +4) —z (5) where a is, not the initial volume of the colloid, but the free space within the jelly before swelling through which the ions may pass. For our hypothetical substance, we may consider the limiting case where the value of a is zero, in which case, from (1) and (5) we get— Ob . (1/V —z)y = Kz (6) and from (2) and (3)— z2=e-+ 2Vey or— z= CV +2V/CVy (7) From (6) and (7)— VK + y)(CV + 2vVCVy) —y=0 (8) where the only variables are V and y. Now we have only to know the values for the two constants, K and C, to plot the curve for any variable in terms of any other value. For example, by giving y a definite value, we can calculate V from (8). Knowing y and V, we can calculate z from (7) and with y and z, we can calculate x from (2), while e is obtained directly from (4). If any values for K and C be substituted, the resulting relations will be found to be of the same general nature as are obtained with any proteins in acid solutions, but values of K and C for gelatin have been determined. By means of the hydrogen electrode, Procter and Wilson found the value K = 1-5 x 10~-‘ for gelatin and HCl, while their experimental value for C at 18° was 3 x 10-4. The whole series of curves for these values of the gelatin constants has been plotted, and appears in the Journal of the American Leather Chemists’ Association for 1918, pages 184 and 185, which should be consulted. Procter’s experimental determinations are included in the same figures, and it will be seen that better agreement could not be obtained if the curves were drawn from his data. Since, theoretically, the calculated curves should not coincide absolutely with the experimental ones for gelatin and HCl, it is interesting to note why no appreciable discrepancies were found. 2) ———————— << er 6. %¢@ 57 That the quantity a, defined as the free space within the unswollen jelly, has a measurable value for gelatin is suggested by the fact that the volume of the swollen jelly is slightly less than the sum of the volumes of the gelatin and absorbed water before swelling. But the values for V are generally so much greater than the total volume of the gelatin before swelling that any error due to neglecting a would be insignificant. Appreciable errors might have resulted from the assumption of total ionization of the electrolyte, were it not for the fact that the rates of change of the slopes of the curves are greatest for concentrations of HCl less than 0-01 N. In order to apply the theory to weak acids, it is necessary to include the equation which defines the ionization constant of the acid. Procter and Wilson have derived equations which explain the action of salt in repressing the swelling of gelatin in acid solutions ; for these and others dealing with polybasic acids, reference should be made to the original papers. At the moment of writing no evidence incompatible with the theory has been discovered. EH. A. and H. T. Graham stated that the theory would not account for the repression of swelling by sugars, but Wilson pointed out that the difference in molal fugacity of the sugar in the two phases due to the differences in ion concentrations is sufficient to account for the repressing action of sugar. The possibilities of gain to pure science fully justify the undertaking of the enormous amount of work still to be done on the theoretical side of imbibition and the problem appears to lie as much in the field of the mathematician as in that of the chemist. Recent Publications on Imbibition of Gels, (See also bibliography at end of Part IT.) Arisz, L. ‘The Sol and Gel State of Gelatin Solutions.’ I. Gelatinising. II. Swelling. ‘Koll. Beihefte,’ 7, 1 (1915). Size of gelatin particles and attractions between them probably decrease during swelling. Swelling and solution are considered two stages of the same process, indefinite swelling amounting to solution. Bennett, H. G. ‘ The Swelling of Gelatin.’ ‘J. Soc. Leather Trades Chem.’, 2, 40 (1918). Polemical. FiscHer, Martin H. Epema and Nepureiris. (J. Wiley & Sons, 1915.) On Hydration and “Solution” in Gelatin. ‘Science,’ 42, 223 (1915). A warning against the general adoption of the view that the “ solution” of a protein represents but the extreme of that which in a lesser degree is called swelling. Hydration or swelling is to be regarded as a change through which the protein enters into physicochemical combination with water; ‘‘ solution’”’ as one which can be most easily understood as the expression of an increase in the degree of dispersion of the colloid. Fiscner, M. H. and Sykes, A. ‘The influence of Non-electrolytes on the Swelling of Protein.’ ‘ Kolloid-Z.’ 14, 215. Non-electrolytes decrease the degree of swelling of protein the more so the greater the concentration. The conclusion is drawn that the phenomenon is one of adsorption rather than osmosis. “The Non-acid and Non-alkaline Hydration of Proteins.’ ‘ Kolloid-Z.’ 16, 129 (1915). In the swelling of gelatin by urea, there are two changes, one towards increasing hydration, the other towards increasing degree. of dispersion. Fiscner, M. H. and Hooxer, M.O. ‘On the Swelling of Gelatin in Polybasic Acids and their Salts.’ ‘J. Am. Chem. Soc.’ 40, 272 (1918). 58 Fiscuer, M. H., and Benzrincer, M. ‘On the Swelling of Fibrin in Polybasic Acids and their Salts.’ ‘J. Am, Chem. Soc.’ 40, 292 (1918). FiscHer, M. H., and Corrman, W. D. ‘On the Liquefaction or “ Solution” of Gelatin in Polybasic Acids and their Salts.’ ‘J. Am. Chem. Soe.’ 40, 303 (1918). Granam, E. A., and Granam, H. T. ‘ Retardation by Sugars of Diffusion of Acids in Gels.’ ‘J. Am. Chem. Soc.’ 40, 1900 (1918). HatscHer, Emin. ‘ Viscosity and Hydration of Colloidal Solutions.’ ‘ Biochem. J.’ 10, 336 (1916). ‘An Analysis of the Theory of Gels as Systems of Two Liquid Phases.’ ‘Chem. News,’ 116, 167 (1917). Karz, J. R. ‘ Micella are not necessary for the Explanation of Uncomplicated Swelling.’ ‘ Z. Physiol. Chem.’ 96, 255 (1916). The facts are fully covered “by the theory of a solid solution of water in the swellling substance, and in Nagelli’s theory micella can be replaced by molecules. “The Laws of Swelling. The Swelling in Water without Complications.’ “Kolloidchem, Beihefte,’ 9, 1 (1917). Lenk, Emm. ‘Importance of Electrolytes for Swelling Processes”: A. The Action of the Individual Electrolytes. B. Combinations of Electrolytes.’ ‘Biochem. Z.’ 78, 15 and 58 (1916). The conclusion is drawn that the antagonistic actions of ions must be due to colloidal phenomena and not to osmotic pressures, Lors, Jacques. ‘Ionization of Proteins and Antagonistic Salt Action.’ “J. Biological Chem.’ 338, 531 (1918). “The Stoichiometrical Character of the Action of Neutral Salts upon the Swelling of Gelatin.’ Jbid. 34, 77 (1918). Manazse, K., and Maruna, J. ‘ Physical Changes in the States of Colloids.’ XV. Electrochemical Investigations of Acid Albumin. ‘ Biochem. Z.’ 52, 369 (1913). The work involved the electrometric determinations of the hydrion and chloridion concentrations of hydrochloric acid solutions of serum albumen and of gelatin. OstwaLtp, Woxireane. ‘Importance of Electrolytes for Swelling Processes.’ ‘Biochem. Z.’ 77, 329 (1916). Pavuri, W., and Hrrscuretp, M. ‘ Alteration in the Physical Conditions of Colloids.’ XVIII. Protein Salts of Different Acids. ‘Biochem. Z.’ 62, 245. Equal concentrations of protein bind less of a weak than of a stronger acid. Procter, H. R. ‘On the Action of Dilute Acids and Salt Solutions upon Gelatin. ‘ Kolloidchem. Beihefte, 1911; ‘J. Am. Leather Chem. Assn.’ 6, 270 (1911. This paper contains a great deal of valuable experimental data. ‘The Equilibrium of Dilute Hydrochloric Acid and Gelatin.’ ‘J. Chem. Soc.’ 105, 313 (1914). ‘The Combination of Acids and Hide Substance.’ London ‘ Collegium,’ 1915. A paper dealing with the subject in a more popular style. “The Swelling of Gelatin.’ ‘J. Soc. Leather Trades Chem.’ 2, 73 (1918). A reply to Bennett’s paper of the same title. Procter, H. R., and Witson, J. A. ‘ The Acid-Gelatin Equilibrium.’ ‘J. Chem. Soe.’ 109, 307 (1916). ‘The Swelling of Colloid Jellies.’ ‘J. Am. Leather Chem, Assn.’ 11, 399 (1916). Rincer, W. E. ‘Further Studies on Pekelharing’s Pepsin.’ ‘Z. Physiol. Chem.’ 95, 195 (1915). The action of pepsin and swelling of protein are closely related. 3 ‘Further researches upon Pure Pepsin.’ ‘ Proc. Akad. Wetenschappen,’ 18, 738 (1915). The point of maximum swelling of protein does not occur at the same hydrion concentration with different acids. ‘The Importance of the Condition of the Substrate in the Action of Pepsin.’ ‘ Kolloid-Z.’ 19, 253 (1916). } 59 Rosertson, T. B. ‘The Physical Chemistry of the Proteins.’ (Longmans. Green & Co., 1918.) Rosensoum, E. ‘ The Heat of Swelling of Colloids.’ ‘ Kolloidchem. Beihefte,’ 6, 177 (1914). The swelling of gelatin appears to be divided into two phases, the first where a small amount of water is taken up and all the heat of swelling is evident, and the second Where a large amount of water is taken up and no heat evolved. Totman, R.C., and Stearn, A.E . ‘ The Molecular Mechanism of Colloidal Behaviour.’ I. The swelling of Fibrin in Acids. ‘J. Am. Chem. Soc, 40, 264 (1918). Witson, J. A. ‘ Retardation by Sugars of Diffusion of Acids in Gels.’ ‘J. Ams Chem. Soe.’ 41, 358 (1919). A reply to the statement by E. A. and H. T. Graham (see above) that Procter’s theory cannot account for the repression of the swelling of acid-swollen gelatin by sugar. Witson, J. A., and Witson, W. H. ‘ Colloidal’ Phenomena and the Adsorption Formula.’ ‘J. Am. Chem. Soc.’ 40, 886 (1918). A further mathematical development of Procter’s theory of the swelling of colloid jellies and its relation to other branches of colloid chemistry. Wo rrr, L. K., and Bicuner, E. H. ‘ The Behaviour of Jellies towards Liquid, and their Vapours.’ ‘ Verslag. K. Akad. Wetenschappen,’ 21, 988 (1912) and 22, 1323 (1914). It is contended that von Schroeder’s observation that the amount of water in gelatin swollen in liquid water decreases when the gelatin is placed in water vapour rests upon a defective method of experimentation. IMBIBITION OF GELS. PART II.—_INDUSTRIAL APPLICATIONS. By Joun Artuur Witson, Chief Chemist, A. F. Gallun & Sons Co., Milwaukee. Imbibition plays a most important role in the manufacture of leather, paper, textiles, and many other colloidal products, but few cases are generally known of applications of theory to manufacturing conditions. In view of the fact that Procter’s theory grew from an investigation of the process of pickling hides, it is not surprising that what applications of it have so far been published have been connected with the leather industry, especially since many of the formulas are of recent derivation. A general survey of applications, to the leather industry has been given by Procter in the First Report pp. 5-20, and need not be repeated here. Wilson and Kern used the theory to explain causes for certain discrepancies in tannin analyses made by the hide-powder method, which is widely employed both in Europe and America. One direct outcome of the theory of: imbibition is the Procter-Wilson theory of vegetable tanning, which like its parent theory is largely mathematical in character. The equations forming part of the theory enable one to regulate the astringency of the tannins, their rate of diffusion into the hide, and the degree of plumping of the hide fibres, by simple alterations of the concentrations of electrolytes in the tan liquors. Bovard, in pointing out the importance of imbibition to the - manufacture of paper, claims that the character of the sheet is largely determined by the degree of hydration and length of the fibres. He noted that cellulose swells more rapidly in alkaline than in neutral or acid solutions, and since the rosin size used in paper manufacture is alkaline, he reasoned that the hydration of the stock would be 60 promoted if the size were added to the beater before the alum. In an actual test, working in this order, the paper tested 14 points higher than that made by putting the alum into the beater first. Photographic workers sometimes experience a most annoying reticulation of the surfaces of negatives, particularly when fixing or washing during hot weather. The wet gelatin layer becomes finely wrinkled or corrugated, the network of puckers forming a pattern. Sheppard and Elliott have found two causes for this difficulty. When sheets of gelatin swell or contract slowly, they undergo a change in volume but not in shape. On the other hand, the gelatine on a negative must undergo a change in shape, since one face of it is held to the plate. So long as the amount and rate of swelling are not great, no trouble is experienced, but when the swelling is excessive, due to higher temperatures or chemicals in the fixing bath, the upper surface of the gelatin will have an area so much greater than the lower surface as to cause puckering. The second cause is the presence in the solution with which the plate is treated of both swelling and contracting agents. Reticulation is readily produced by immersing the plate in a solution containing acetic and tannic acids, the former tending to swell or soften the gelatin, the latter to contract or harden it. Their rates of diffusion are determined by their effects upon the gelatin, and the result is a mosaic-like alternation of hardening and softening effects, the ridges being more swollen and the valleys contracted by tanning. Judging from the literature available, the most extensive applications of imbibition have been in the field of biology. Almost without exception, this has been done by analogy, rather than by application of theory. Fischer’s book, “Edema and Nephritis”’ is replete with analogies between inbibition of such proteins as gelatin, fibrin, and gluten, and that of things so widely different as muscles, eyes, nervous tissues, catgut, and living frogs. Loeb showed that the behaviour of dried pig’s bladder in solutions of various salts very closely resembles that of powdered gelatin in the same solutions. Reference should also be made to Loeb’s work on the fundulus egg, to Arnold’s studies of the swelling of human muscle, and Traube’s work on the swelling and germination of plant seeds. Recent Publications Dealing with the Application, or Suggesting an Application? of the Subject of Imbibition of Gels. (See also Bibliography at end of Part I.) Arnotp, R. ‘The Swelling Capacity of Different Kinds of Muscle in Acid Solutions.’ ‘ Kolloidchem. Beihefte,’ 5, 511 (1914). The structure of human muscle is not a criterion of its relative swelling capacity. Bovarp, W. M. ‘Colloidal Chemistry in Papermaking.’ ‘Paper’ 22, 11 (1918). Shows the importance of controlling hydration of the stock in making paper. Fiscuer, M.H. ‘:Relation between Chloride Retention, Edema, and ‘‘ Acidosis.” ‘J. Am. Med. Assn.’ 64, 325 (1915). ‘The Classification and Treatment of the Nephritides.’ ‘The Journal- Lancet,’ July 1, 1916. FiscHer, M. H., and Hooxrer, M. O. ‘Trench Nephritis.’ ‘The Int. Assn. of Med. Museums,’ Bulletin No. VII., May, 1918. ‘Ternary Systems and the Behaviour of Protoplasm. ‘Science, 48, 143 (1918). Many of the laws governing the hydration and dehydration of soaps OT 61 are identical with those governing the hydration and dehydration of certain proteins, which in turn show analogies to living cells. Harrison, W. ‘Investigations on the Physical and Chemical “Properties of Cotton. Report of ‘The Nat. Assn. of Cotton Mfrs.’, 1916. Lors, Jacgurs. ‘The Mechanism of the Diffusion of Electrolytes through the Membranes of Living Cells.’ I. The Necessity of a General Salt Effect upor the Membrane as a Prerequisite for this Diffusion.’ ‘J. Biol. Chem,’ 27, 339 (1916). II. The Diffusion of Potassium Chloride out of the Egg of the Fundulus and the Relative Efficiency of Different Ions for the Salt Effect. Ibid., 353. III. The Analogy of the Mechanism of the Diffusion for Acids and Potassium Salts. Ibid., 363. ‘The Similarity of the Action of Salts upon the Swelling of Animal Mem- branes and of Powdered Colloids. Ibid., 31, 343 (19177). Procter, H. R. ‘Recent Developments in Leather Chemistry. ‘J. Royal Soe. Arts,’ 1918. ‘Colloid Chemistry of Tanning. ‘First Report,’ p. 5. Procter, H. R., and Burton, D. ‘The Swelling of Gelatinous Tissues.’ J. Soc. Chem. Ind,’ 35, 404 (1916). Treats the subject from the viewpoint of the leather chemist. ; Prootrer, H. R. and Witson, J. A. Theory of Vegetable Tanning. J. Chem. Soe,’ 109, 1327 (1916). SHEPPARD, S. E., and Exxiorr, F. A. ‘The Reticulation of Gelatin.’ J. Ind. and Eng. Chem.’ 10, 727 (1918). An application to photography. TRAUBE, I., and Kéuter, F. ‘The Velocity of Formation and Solution and of Swelling of Gels.’ ‘ Intern. Z. Biol.’ 2, 42 (1915). A discussion is given of the relation between experimental results and the following biological problems : narcosis, plasmolysis of cells, chemotaxis, muscular work, edema, and inflammations. TrRAUBE, I., and Marusawa, T. ‘Swelling and Germination of Plant Seeds.’ “Intern. Z. Physik. Chem. Biol.’ 2, 370 (1915). Upson, F. W., and Catvin, J. W. On the Colloidal Swelling of Wheat Gluten,’ “J. Am, Chem. Soe.’ 37, 1295 (1915), Wuson, J, A. ‘Theories of Leather Chemistry.2 ‘J. Am. Leather Chem. Assn.” 12, 108 (1917). ‘Theory of Tanning,’ 2bid., 18, 177 (1918). ‘Theory and Practice of Leather Chemistry,’ ibid., 14, 93 (1919). Wuson, J. A., and Kern, E. J. ‘The Non-Tannin Enigma.’ ‘J. Am. Leather Chem. Assn.’ 18, 429 (1918). COLLOID PROBLEMS IN BREAD-MAKING. By R. Wuymesr, Chief Chemist to Messrs. Peek, Frean & Co., Lid., Biscuit Manufacturers, London, and late Assistant Inspector of Bakeries, B.E.F., France. There is no manufacturer less aware of the chemical problems underlying his trade than the master baker. In spite of his ignorance, however, he is one of the most efficient members of society, in that he produces an excellent article with great regularity. This is, perhaps, less a matter of wonder when it is realised that the art of bread-making of a high order can be traced through the Chinese to about 2,000 years B.c., and is of course older than that, and that ot to this day the majority of people can make a very passable oaf. Such scientific work as has been done, in or for the bakery, has usually been undertaken for some specific material object, for advantage to the large manufacturer (yields, moisture retainers, effect of machinery) or for the protection of the consumer (sanitary conditions of manu- facture, effect of alum, bleaching agents, &c.). There is comparatively 62 little published work available to show that the problems have been tackled for,a scientific purpose, or for improvement of the process. _ Indeed, there has been no stimulus for the chemist, since, in the bakery the ability of a master baker to feel, taste and smell the ingredients is a more sure guide in the production of good bread than the know- ledge obtained by use of test tubes and balance. It will be observed that the two points of view, that of the producer and that of the consumer, are largely but not entirely sympathetic. The former, whether the small hand-baker or large manufacturer, demands the greatest yield from hisingredients, and the most attractive- looking product, but really is not greatly concerned about the flavour, provided he can sell his bread. The result is the exhibition loaf of perfect proportion, if somewhat insipid, or the water-laden and profitable loaf, both the outcome of scientific treatment. All the consumer asks to-day is that his bread shall be palatable, and be made in a cleanly manner and cheap, whilst he is not greatly interested in the amount of water present in his loaf. Such a loaf, to suit the consumer, can generally be assured by the hand-baker. It is therefore rather in the economic direction that any considerable amount of work has been done by the bakery chemist, who himself is only just beginning to realise the variety and complexity of the problems underlying the art. That he will, at a near date, assume supreme importance in the bakery, especially in the large machine or automatic bakery, is certain, but the time is not yet, for he does not know enough and, above all, the master baker is well aware of the fact. It is easy to analyse all the ingredients in use in the bakery, but it is less easy to determine how a combination of these ingredients will turn out as bread, since the mutual influence of one complex upon another is not known with any degree of certainty. It is unfortunate also that so many technologists, having acquired a smattering of chemistry, pose as scientific experts, with the result that conflicting opinions, arising from the interpretation of inaccurate results, have injured the prestige of the chemist. On the other hand, the chemists have not been free from the fault of supplying, from a laboratory, advice which clearly indicates that they do not know the elements of bread-making. Briefly put (for it must be assumed that the elementary principles of bread making are understood by the reader), bread is made from flour, yeast, water and salt, with occasionally milk, fat, malt extract, yeast salts, wheat germ, aerating chemicals, &c., according to the quality of bread required, English bread, farmhouse bread, milk bread, germ bread, malt bread, tin loaves, Viennese rolls, French rolls, &c. With the addition of any new ingredient over the first four mentioned, fresh complications in the chemical changes during bread- making are introduced. Added to these must be considered the changes involved during fermentation and baking, and, one of the largest problems of all, during the change from freshness to staleness which the loaf undergoes with the passage of time. With the use of flour, yeast, water and salt alone, a mixing of dough, and the subsequent loaf, are of sufficient complexity, involving the saturation 63 and swelling of the starch granules (for future gelatinisation by heat), the production of hydrated forms of gluten, itself a complex proteid, biological changes during the growth of yeast, the occlusion of gas , evolved during that growth, the action of the yeast enzymes on the carbo-hydrates, the working of the dough to secure suitable elasticity, proteolytic enzyme action on the gluten, the hardening action of salt on the gluten, gelatinisation and saturation of the starch-water system on baking, and the gradual changes, physical and chemical, during cooling and ageing which bring about eventual staleness. This is but a broad outline of the problems to be attacked when the barest necessities for the production of bread are used, and it is evident that the addition of milk or fat must increase the complication of the bread system. I.—Flour. The flour components of greatest importance are starch, gluten, mineral salts and enzymes. (a) Starch. Some space has already been devoted in Report I. (p. 46 et seq.) to the consideration of wheat starch and its behaviour in the presence of water at a temperature to cause gelatinisation. It is not intended to cover this ground again. Wheat starch in the presence of a sufficiency of water will commence gelatinisation about 60° C., and every granule will be completely burst at about 65° C. Since the baking temperature of a bread oven is usually between 200° and 240° C., and the amount of water present in a normal dough is about 41 per cent., the baking lasting for one hour, it might be imagined that, all other factors removed, a great proportion of the starch granules to be found in bread-crumb would be gelatinised. Yet, as a rule, the starch granules inside a loaf show a mixture of those untouched by the damp heat and of those only slightly swollen, whilst a few only have undergone complete gelatinisa- tion. The reason for this divergence from theory may be found in the fact that a temperature seldom higher than 95° C. is reached within the loaf, and then only for a very short period, during the baking hour, though temperatures as high as 99-5° C. have been recorded. It is probable that the time factor is of some importance here. Further, the saturation of starch by water is reached when a mixture shows 41 per cent. of the latter, hence, after allowing for the absorption of water by gluten (which is not inconsiderable, being as much as 200 per cent. of the dry gluten of a strong flour and slightly less for weaker flour), there is an insufficiency of water present to allow complete gelatinisation of all the starch granules at the temperature of baking. The complexity of the colloid systems in a baked loaf is, therefore, considerable. Were there no component other than starch to consider, such problems as the change in physical consistency from freshness to staleness of a loaf would be comparatively easy of solution. But there are so many underlying difficulties connected with dissolution by enzymic action on the one hand, and coagulation by electrolytes on the other, that the behaviour of the colloids in the loaf after 64 baking is less easy to interpret. It must not be forgotten, moreover, that gluten, so far as can be ascertained, hinders the deposition of _ starch from its jelly. At any rate, by the addition of extra gluten to flour-dough the resulting bread possesses better keeping qualities, which, from our recent researches (Whymper, R., “ Z'he Conditions that Govern Staleness in Bread,” Maclaren and Sons, Ltd., 1919) in the Army, have been shown to depend chiefly upon the: rate of deposition of starch from its solutions with the passage of time. In other words, gluten acts as a protective colloid to starch in solution. Exception may be taken to such a generalisation as this, on the ground that it is the quality of the gluten that determines whether bread will keep well or quickly become stale. Snyder (U.S. Dept. Agric., Bull., 101, 56, 1901) found that the addition of starch or the addition of gluten, the former up to 20 per cent. of the flour, was without material effect upon the size of the loaf, though the water- absorbing capacity of the starchy flour was reduced. We are of the opinion, however, that the conclusion reached by that worker and by Jago (“ The Technology of Bread-Making,’”’ 1911, p. 305), that “the character rather than the quantity of the gluten content ” governs the quality of bread, is too far-reaching, since they omitted to consider the keeping qualities of the loaf. Jago’s figures for the viscometer readings of a similar experiment are not without interest (Table I.), for, though of a rough order, they give some indication of a previously observed fact, that, in the case of flours of high water- absorbing capacity, this power is retained but little diminished on being reduced to a uniform wet gluten-percentage level by the addition of wheat starch. TABLE I. ° Viscometer Determinations on Mixtures of Flour and Starch. (Jago.) as II. III. IV. Vv. VI. VII. Second Class British | British Spring | Winter | Winter English | Milled | Milled Ameri- | Ameri- | Ameri- | Hun- | Wheat | First | Second can can can garian | Patent. | Patent. | Patent. Patent. | Patent. | Bakers. | Patent. Original percentage of wet gluten - 39.2 28.2 32.0 35.0 27.75 31.9 38.4 Water - absorbing ; power by visco- meter - - | 68.6 54.8 69.0 76.0 61.0 60.5 64.0 Viscometer readings on gluten being reduced by ad- mixture of starch to— 35 per cent. - 65.0 — — = a = = 3 » - 62.7 — = 71.3 — 60.0 63.0 25 t - 62.0 55.5 66.0 70.7 59.5 = = 20 »” : 61.4 55.4 62.0 66.0 57.5 57.5 58.5 Weight of starch added to 100 parts of flour to reduce gluten to 20 per cent. - - 96.0 41.0 60.0 75.0 38.75 59.5 92.0 EO = 65 With regard to starch solutions and starch pastes, some viscosities have already been given. (Report I., p. 47. See especially Samec, 1911, Koll. Chem. Bethefte, 3, 123-160; 1912, idem, 4, 132-174; 1913, idem, 5,,141-210.) Elsewhere (“‘ The Conditions that Govern Staleness in Bread,” 1919) the present writer has observed that “ the change in viscosity, with time, of starch paste follows a general rule in that, at first thinly viscous when first prepared (hot), it sets to a jelly, and later becomes thinly viscous again.” Pure supsensoids change their viscosities (usually a decrease) in days, the more typical emulsoids showing an increase in viscosity much more quickly. It is assumed that, in starch paste, the latter changes are masked by the slower changes of the former. As a matter of fact, the curve (viscosity plotted against time) is of a distinct S shape, the changes being more marked the more concentrated the solution. The solutions worked with were prepared by digesting 8 grams of wheat starch (containing 10-8 per cent. water) in 180 c.cs. of water, and boiling till the clearest paste was obtained. Other figures of interest obtained with such a solution are shown in Table II., but should be compared with those in Table III. showing the same methods applied to Doughs and Bread-crumb, since, in every case, it is clear that the principle under- lying changes in starch paste need not necessarily be reproduced in bread-crumb, in which the phases are so differently distributed. TABLE II. Starch Paste. Soluble Colorimetric Apparent Extract* on Value of = == Moisture, | Bone-dry Solids | Extract with per cent. per cent. standard lodine solution. I | After 30 minutes cooling 95-90 [19-15] 1-31 blue II ap 6 hours 35 95-95 [12-74] POS sy Iil JD ZA 193) _ 95-92 [7-62] fo. ays " a) ‘ sak O- O7 ” IV iy Lo uass as 935-97 | [19-5] 0-104. red - ‘ Lee 0-04 blve Vv cys A aaee ups 96-84 [16-55] 0-05 red : 0-08 blue 95 2 VI Bee ROO 5 a 95-95 [17-26] 0-2] red mtrt | 5, 14a, e 95-99 [33-91]+ 0434 blue 0-20 red * These values are unreliable, owing to magnification of experimental error by calculation. + After 150 hours a still higher figure was obtained, w 11454 E 66 TaBxe III. Doughs and Bread-Crumb. Soluble Colorimetric Apparent | Extract Value of — Loaf weights Moisture | on Bone- | Extract with in grams. per cent. | dry Solids |standard Iodine per cent. solution. ae _f 0-21 red Dough after mixing _ 41-21 10-07 0-05 yellow Dough after proving a 41-10 9-76 Nil. Original 997 ait : 1-10 blue. Bread 6 hours old - 6 hours 973 41-42 12-84 2-50 red Original 995 } 6 hours 972 1& blue Bread 70 hours old- 24 hours 964 41-35 15:31 0:25 red 48 hours 952 70 hours 945 Among other conclusions reached by this research were :— 1. The loss of water during cooling and drying-out of a loaf is not responsible for staleness. 2. During the process of becoming stale, there is a fall in soluble extract obtained from the crumb, followed, after a time, apparently independent of staleness, by a rise. The soluble starch in bread- crumb (as shown by the iodine colouration) drops rapidly between 6 hours’ and 24 hours’ cooling. 3. Investigation shows that a similar fall and rise of soluble extract is to be seen in starch pastes, whilst the iodine colouration follows the same rule observed in bread-crumb. 4, Staleness may be attributed to— (i) Deposition of solid starch in the crumb of bread, starting between 6 hours and 24 hours’ cooling period— (a) By change of temperature ; (b) Accelerated by the presence of solid starch particles already existing in the crumb. (ii) Partial polymerisation of starch, independent of the deposition already stated, which tends to crumble the gelatinous nature of the bread-crumb when fresh. The statement in 4 (i) (b) is open to dispute, for we have no actual proof that the deposition of solid starch from solution is accelerated by the presence of other solid particles. This work is even now in progress. On the other hand, the statement made in para. 4 (i1) is, we believe, substantially correct, for the following reasons, which must be taken in conjunction with the figures given in Table II showing the soluble extracts from starch paste decreasing with time, (especially as indicated by the iodine colouration) :— If we take the suspension of starch granules in water as the starting point of our consideration, it is seen to be a coarsely disperse system, . 67 or a crude suspension of colloid matter in a dispersion medium, increasing in uniformity of distribution as the subdivision of the suspended particles is increased. Such a system allows almost complete separation of the dispersion means by filtration through an ordinary filter paper. The ordinary filter paper will hold back particles having a diameter greater than about 5u, though, according to the method of preparation, filters can be obtained which will stop the passage of particles down to an approximate diameter of 2 wp. According to E. F. Armstrong (Brit. Assocn., 1909), the smallest wheat starch granules vary from 3 to 5 y, and the largest from 30 to 35 yz, so that the filtration of the water from the granules should be almost complete. This, in practice, has been observed to be the case. The simplest form of starch has been given (Brown, H. T., and Morris, G. H., Jour. Chem. Soc., 58, 610, 1888) a molecular formula [(CysH001)20];- Lobry de Bruyn and Wolff (Rec. Trav. Chim. des Pays. Bas., 23, 155, 1904) estimated the size of the starch molecule to be approximately 5 yu, as compared with hydrogen gas 0-067— 0-159 pu, and water vapour 0-113 py. Soluble starch prepared by the action of ozone on common starch was examined by Friedenthal (Physiol. Zentralbl., 12, 849, 1899). who obtained a molecular weight of 9,450 as against 32,400 in the formula above. The product obtained in this way was clearly more highly dispersed than ordinary starch, a fact borne out by the definite depression of the freezing point of water containing it in contrast to a suspension of ordinary starch or to a starch paste. Depression of Freezing Point of Soluble Starch. Concentration per cent. Depression of the Freezing Point. 2-5 0-005 , 5-0 0-01 10-0 0-02 On the figures of Lobry de Bruyn and Wolff, “‘ if a cubic centimeter of dry starch could be subdivided into its molecules or dissolved in the ordinary sense of the word, the starch would present a total surface of several thousand square metres towards the solvent,” and, in doing so, would pass from an average size of its individual particles of 20 wu through the value 0-1 yu, which represents the limit of microscopic visibility, to a value of 1 yy, a figure somewhat smaller than that of a particle hitherto observed with an ultra-microscope. It is between the last two values that colloid chemistry has to deal, according to Zsigmondy’s system of classification. (Zsigmondy, R., Zur Erkenntnis der Kolloide, X XII., Jena, 1905.) With regard to filtration of colloids through various papers and diaphragms, a considerable amount of work has been done, the most interesting for the immediate purpose being that by Bechold (Zeitsch. physik. Chem., 64, 328, 1908). Bechold’s results, from his experiments with the pores of filter papers, cannot be taken as absolutely accurate during prolonged filtration of colloid solutions, E 2 68 since absorption effects are often observed, due to the action of the paper on the dispersed phase, and often lead to clogging of the pores of the filter. The results are, however, interesting, since they show that typical colloids, with particles having a diameter less than 0-1 p, are easily able to pass through all the filters tested. Size of Pores in Filters. Average Size of Pores Filter. (Permeability to Water). Ordinary thick filter paper - - - 3°3 ps Filter paper, No. 556. (Schleicher and Schill) - - . - - - - Lay Filter paper, No. 602. (Extra hard, Schleicher and Schill) - - - - 0-89-1-3 yu The degree of solubility is also of importance in this question of filtration, chiefly because the solubility of a substance is dependent upon its specific surface, or, in other words, the solubility rises greatly with the extreme subdivision. The jelly concentration of silicic acid was found by Graham (Jour. Chem. Soc., 1864), in the very early days of colloid chemistry, to influence the maximum molecular solubility in excess of water. Thus he found that only two parts of | per cent. silicie acid jelly formed a molecular disperse solution in 10,000 parts of water, one part of a 5 per cent. jelly, and less of greater concentra- tions of jelly in the same amount of water. Concentrated jellies, therefore, are less disperse than the more dilute, and so have a lower molecular solubility. The low solubility of gelatinised starch will be appreciated when the figures shown in Tables IT. and III. are compared. The viscosity, of starch solutions and separation of starch paste into two phases has already been pointed out in the First Report (p. 49), but, before passing to other points, it is as well to consider another aspect of true soluble starch. Some description’ of soluble starch has already been given in a previous Report (No. IL. p. 51), but there is little doubt that confusion has arisen owing to its variable nature according to the method of its preparation. Soluble Starch.—Soluble starch paper, prepared by the action of diastase or acids on starch paste or by heating dry starch in a suitable manner (Zalkowski, Chem. Zeit., 1888, 1060), is soluble only to a very small extent—about 2-3 per cent.—in cold water, yet itis possible to obtain a preparation, by the action of sodium peroxide (Syniewski, Ber., 1897, XXX., 2415) on starch suspended in water, that is soluble to the extent of some 12 per cent. in the cold. The latter seems quite a different compound to that prepared by Lintner’s method with diastase. The varied descriptions of the behaviour of soluble starch when placed in water, dissolved and subsequently cooled, would add weight to the conclusion that it was not always the same kind of soluble starch that was under consideration. It may, and usually does, form a thin opalescent paste, remaining fluid on cooling, however prepared, but it does not always revert to the insoluble form in time. Fouard (Compt. Rend., 1908, 97, 931-3) used a soluble starch that reverted Co ry ae ae 69 apparently in a comparatively short time, whilst the writer, in Table IV., has shown that, if there were any reversion at all after 144 hours, in the soluble starch that he employed, it was quite insignificant. There is undoubtedly a small quantity of true soluble starch formed in bread-making. Tassie IV. Soluble Starch. (From Messrs. Baird and Tatlock.) Soluble Apparent Extract* on Colorimetric — —— Moisture Bone-dry Solids Value. per cent. per cent. I | After 30 minutes’ cooling 95-97 [82-38] 1:78 blue II - 6 hours’ a 96-05 [84-05] 100 ees iit SM ee as 13 95-93 [77-64] U:68s 5, TV eel Sh we 96-04 [77-52] LO De iss Vv = NE of 95-94 [72-66] SOR: VI BAe OGit ss ‘3 96-06 [89-34] 1-43 ,, VII apg nds sa 96-69 [83-38] Oey ce * These figures are open to less error than those for starch paste, owing io the greater amount of soluble matter actually present. (b) Gluten. : Wheat gluten has been briefly referred to in Report I. (p. 72), from which it may be gathered that the proteid is itself a mixture of coagulable albumin, glutin, and gliadin. These more or less distin- guishable proteids have been again subdivided by Osborne and Voorhees (Amer. Chem. Jour., 1893, “The Proteids of the Wheat Kernel’) into glutenin, gliadin, globulin, albumin, coagulum, proteose, and certain nitrogen compounds soluble inwater in the following proportions, for flour milled from specified wheat :— TABLE V. Composition of Wheat Gluten. (Osborne and Voorhees.) Spring Wheat. Winter Wheat. — Nitrogen x 5:68 = Proteid. | Nitrogen x 5-68 = Proteid. Glutenin - - 0: 8245 = 4-683 0: 7346 = 4-173 Gliadin - - 0: 6977 a 3° 963 0: 6884 = 3-910 Globulin” - “ 0: 1148 = 0-624 0-1148 = 0-625 Albumin - = 0: 0657 = 0-391 0- 0603 = 0-359 Coagulum - - 0- 0453 = 0-269 0: 0379 = 0-223 Proteose - - 0: 0341 = 0-213 0: 0791 = 0-432 From water- 0: 2239 = 1-272 0- 1552 = 0-881 washings of Glu- ten. Total - 2- 0050 = 11-415 1-8703 == 10-603 In meal - - 2-10 — 11-93 1-94 = 10-96 70 Gluten of wheat flour is therefore a variable colloid when met with in the bakery. It is upon the proportion of glutenin to gliadin and upon the amount and quality of salts present that the nature of the gluten of wheat flour depends. Unless these proportions are known (obtainable only by laborious effort in the laboratory), it is not possible for the chemist to predetermine the quality of the _ resulting bread. “Washing out” accompanied by baking trials are the speedier tests for the quality of a flour. Glutenin is insoluble in water, saline solutions and dilute alcohol, soluble in dilute acids and alkalis, and reprecipitated from such solutions by neutralisation. Gliadin is insoluble in absolute alcohol; soluble in dilute alcohol, (slightly in 90 per cent. and very soluble in 70-80 per cent. alcohol), from which it is precipitated by adding a large quantity of water or strong alcohol, especially in the presence of much salts. It is soluble in distilled water, forming an opalescent solution from which it is precipitated by addition of sodium chloride. Globulin is soluble in sodium chloride solutions, precipitated therefrom by dilution or saturation with magnesium sulphate or ammonium sulphate, but not with sodium chloride. Partly pre- cipitated by boiling, but not coagulated at temperatures below 100° C. Albumin is precipitated from its solution by saturating with sodium chloride or magnesium sulphate. Coagulated at 52° C. Coagulum and proteose are both probably formed during the extraction of the gluten with water. The former is precipitated by saturating its solution with sodium chloride, or by adding 20 per cent. of sodium chloride and acidulating with acetic acid. On concen- trating this solution, the proteose is coagulated, leaving behind a proteid called coagulum, which has not been separated in a pure state. The behaviour of wheat gluten under the influence of salts is, therefore, clearly the result of complex and mutual action among the various colloid components and electrolytes. Very little more can be said definitely. Ostwald and Liiers [Koll-Zeits. 25, 26-45, 82-90, 116-136, 177-196, 230-240 (1919); 26, 66-67, (1920)] were evidently working on the colloid chemistry of bread at the same time as the present writer who, unfortunately, has not had an opportunity of seeing the complete papers. The general results obtained seem, however, to bear ont the conclusions reached by us in 1918, and published in the British Baker in the following year. Ostwald and Liters have found that the chief differences between flour, dough, and new and stale breads, are of a physical rather than of a chemical nature, and these workers have studied each material separately as a colloid, in much the same way as we have done. The viscosity of various mixtures of flour and water, containing as much as 20 per cent of flour, were made, and mixtures of wheat “flour and water were compared against rye mixtures. It was found that rye mixtures became more viscous, whilst wheat mixtures became thinner, on standing, and that traces of acids greatly increased the viscosity of the wheat mixtures, whilst sodium chloride appeared to reduce it. One point of great importance was established, viz., that a flour of 71 poor baking quality invariably gave viscosity figures considerably below those of good flours. The action of gliadin in gluten was also studied, and the viscosity of gliadin solutions was found to be increased by traces of acids and alkalis, and diminished by neutral salts. Further, the viscosity of gliadin solutions was greatly affected by change of temperature, and it is interesting to observe that the temperature at which the maximum viscosity was reached was also the temperature at which the best doughs and breads are produced. The more recent work of Wood, on the action of acids and salts on gluten, has already been briefly outlined in the First Report, but his subsequent comments (Wood and Hardy, Proc. Roy. Soc., 1909, B. 81, 38), made to bring the phenomena of the solubility of gluten into harmony with the ionisation theory, cause rather a strain upon the imagination. We may well believe that “the variations in coherence, elasticity and water content, observed in gluten extracted from different flours, are due rather to varying concentrations of acid and soluble salts in the natural surroundings of the gluten than to any intrinsic differences in the composition of the glutens them- selves,” but it is less easy to understand that the formation of aqueous solutions of gluten “is due to the development of electric charges round the particles of the proteid owing to chemical interaction between proteid, acid, or alkali, and water,” and that the converse, “the tenacity, ductility and water-content of a solid mass of moist gluten depends upon the total or partial disappearance of these electric double layers (supposed to surround each particle of solute), and the reappearance of what is otherwise obscured by them, namely, the adhesion, or ‘ idio attraction’ as Graham called it, of the colloid particles for each other, which makes them cohere when they come together.” This may be the explanation, but it does not help us largely in predetermining the quality of the bread from any particular flour, especially as the glutens were treated after washing out and not in their normal surroundings. Weyl and Bischoff (Jago, “The Technology of Bread-making ’’) showed that a flour moistened with a 15 per cent. sodium chloride solution gave a dough that had lost its tenacity. Flour baked for several hours at 60° C. can also not be doughed. Both experiments have given rise to the theory that a ferment “ myosin” is largely responsible for the ultimate production of gluten during doughing. Distilled water dissolves a certain amount of gluten from flour, and leaves the dough sticky rather than springy. Soft alkaline water destroys the springiness of gluten by disintegration of the gluten, and by prevention of the coherence of its particles. Hard waters, especially those containing much sulphates, harden the gluten considerably. Chlorides generally are more gentle in their action and, up to a point, assist the water-absorbing and retaining power of gluten. For other information concerning gluten and its components, see also :— Jour. Amer. Chem. Soc., 263, Guess (1900); 1068, Snyder, and 1657, Cham- ae a 8, Norton (1906); 74, Matthewson (1908); 1295, Upson & Calvin 72 Jour. Soc.Chem. Ind., 1417 Arpin (abs.) (1902); 368, Baker & Hulton (1908). Canadian Dept. Agric., [57], 37, Shutt (1907). Jour. Board Agric. Supp. 4, 29, Saunders (1910); 52, Hardy (1910). Agric. Gaz., N.S. Wales, Guthrie (1896). Compt. Rend., 128, 755, Fleurent (1896); 182, 1421, Fleurent (1901). Agric. Expt. Stn., Arkansas, Bull 53, Teller (1898). U.S. Dept. Agric., Bull 101, 56, Snyder (1901). Zeit. anal. Chem., 44, 516, Osborne & Harris (1903). Jour. Agric. Soc., 2, 1, Humphries & Biffen (1907). (c) Mineral Salts. The character of bread and, incidentally, the character of gluten are so intimately connected with the action of mineral salts (or other electrolytes) upon colloids, that reference should first be made to the collection of information to be found in the two previous Reports. The works of Wood and Hardy have already been referred to, and scattered through the literature on colloids may be found many other ‘references to the influence of various salts upon wheat gluten, the chemical composition and original nature of which is seldom specified. The “ maturing of gluten” is often mentioned in technical works, and means little else than modifying a “ short ”’ gluten to a condition by which it is capable of retaining the gas generated by the yeast. Kohman and Hofiman (Jour. Ind. Eng. Chem., 1916, 8, 781-9; 1917, 9, 148-59) have made special claims for potassium bromate in this connection, and have employed it in a special yeast food which was used in the U.S.A. Army with great success. It should be noticed that the action of potassium bromate is more effective the higher the grade of flour used, both in modifying the gluten and in improving the colour and texture of the bread (Rep. Conn. Agric. Expt. Stn., Bull, 200, 1917). The addition of alum was but another attempt to modify a bad gluten, the hardening or coagulating effect of that chemical upon many colloids being well known (Odling, Jour. Soc. Arts, 1858). As a rule, alum was only employed on old or damp flour, in which the gluten had deteriorated due to the action of acetic or lactic acids. [See also the ancient use of sulphate of copper for improving flour. (Liebig, “ Letters on Chemistry ’’).] Deterioration with age of the physical qualities of gluten for bread-making is also well known (Whymper, R., ‘“ Knowledge,” 386, 85, 1913), whilst the maturing effect on flour gluten of time and bleaching materials should be considered. (Rep. Local Govt. Board, 1911, I. and IL., N.S. 49, Food Report 12, by Hamill and Monier- Williams respectively.) The nature of the water used in bread-making is of as much importance in securing quality as in brewing. It is, of course, the quality of the contained mineral salts in the water that determines the suitability or otherwise of any given source. The action of the salts is not only upon the starch and gluten colloid systems but also upon the degree and speed of development of yeast cells. The effect of soft and hard waters upon gluten has already been mentioned ; that upon yeast nd fermentation can be found in any text-book (Reynolds Green, ‘‘ The Soluble Ferments and Fermentation,’ &c.). | It is not without interest in the latter connection that Miiller 73 (Ber. d. deus. chem. Gesell., 8, 679, 1875) has found that diastase in the presence of CO, can act upon unboiled starch. (d) Enzymes. The colloid problems of enzymes have been reviewed in Report IL., and but little can be added to this information so far as bread-making isconcerned. Those enzymes that have to be considered are principally maltase, diastase, invertase, zymase, and certain proteolytic enzymes that are not easy to identify. Of considerable interest to us is the future development of the work of Panzer (Zeitsch. physiol. Chem., 98, 316, 339, 1914) on the activation of carbohydrates. This worker found that dry lactose treated with dry hydrogen chloride and subsequently with ammonia acquires feeble amylolytic power. The same, he states, to be true of starches, dextrins, gum arabic, maltose, dextrose, levulose, and galactose. (See also Jour. Soc. Chem. Ind., 1908, 389, Ford and Guthrie.) I1.— Yeast. The work of Professor Bayliss in Report IT. (p. 117), surveying the existing knowledge of protoplasm, its nature and properties, and of enzymes that regulate the chemical reaction of the living organism, fully covers the experience of the bakery chemist so far as yeast is concerned. The problems are by no means simple, and involve the biological history of Saccharomyces cerevisiz (see Lafar, “‘ Technical Mycology ’’) in a variety of media (see Jago, “The Technology of Bread-making,’’ Chap. X1.), and the action of the enzymes contained in and produced by the yeast, as well as certain bacteria, such as the lactic, butyric, and acetic ferments. The auto-digestion of yeast is particularly interesting and important to the baker, who to-day uses, so largely, compressed yeast containing 70-75 per cent. of water In the Army in France the deterioration of yeast during the hot weather was studied, recourse to barms being frequent there in the summer months. Barms were in constant use in Gallipoli and Mesopotamia during the war. The growth of “rope” (B mesentericus) and moulds should also be mentioned, since their presence must indicate that the bread had become a suitable medium for their propagation from internal changes, and by reason of suitable environmental conditions. IIL. and IV.—Water and Salt. As already indicated, the nature of the water is important in considering the quality of bread produced, and the action of various _ salts commonly found in water, and of sodium chloride in particular, _ upon the strength or quality of wheat gluten has already been outlined. V. et seq.—Fai, Milk, kc. The colloid nature of these ingredients has also been considered in previous reports. When used in conjunction with flour, water, 74 salt and yeast, in quite small quantities, their influence, both on the physical nature and on the keeping qualities of the bread (so far as staleness is concerned), is out of all apparent proportion, however, to the amount present. The present writer has already remarked elsewhere that :— “ The effect of freshness can be enormously increased and sustained for many days by the addition of small quantities of fat. With added fats, up to 3 lbs. to the sack of flour, to doughs made by the short, straight process, the colour is but little impaired, whereas the crust is shorter, the crumb sweeter and more palatable, and the effect of staleness is not appreciated for a much longer time than is the ‘case with bread from the simple standard mixing. The use of half milk and half water, instead of all water, as liquor has a some- what similar effect, and the bread produced from this mixing recalls the home-made farm loaf, which does not appear to change from the original state of freshness for a week or more, if kept in a cool, dry place.” The reason is not so far to seek, yet, up to the present, no figures have been obtained to demonstrate the protective influence of the colloid existence of these added ingredients upon starch solutions. There is little doubt, however, that they prevent the deposition of starch in much the same way as they oppose the setting of cements. COLLOID CHEMISTRY IN PHOTOGRAPHY. By R. E. Stave, M.C., D.Sc., F.1.C., Director of Research, British Photographic Research Association. Introduction. Most photographic processes fall into one of the two following classes :-— (1) The substance sensitive to the light is eventually turned into the pigment. (2) The substance sensitive to light is the support of a pigment already present. In both classes of process the support of the sensitive substance or pigment is usually a dried gel, e.g., collodion, gelatin, gum. As an example of class (1) we will consider the ordinary commercial dry plate. The sensitive film consists of very small crystals of silver — bromide, sometimes containing some iodide, supported in a dried — gelatin gel. On exposure to light some of the grains become develop- able. On development—treating with a reducing agent, e.g., alkaline hydroquinone—the gelatin swells and the developer diffuses into the — gelatin, reaches the grains of silver bromide and reduces to metallic silver those previously made developable by light. As an example of class 2 we will consider the carbon process. A gelatin solution containing a pigment such as finely divided carbon is coated on to a suitable support, dried, sensitised by immersion in a solution of ammonium bichromate and dried again. The print -_—_ ——— es eee eS 75 is exposed behind a negative and is then developed by washing in warm water. Where the bichromated gelatin film has been exposed to light it has become insoluble, where it has not been exposed to light it dissolves in warm water and the pigment is washed away. Since the bottom of the film will have been protected from light by the pigment it will dissolve in water and all the gelatin film will come away from its support. It is therefore necessary to transfer the gelatin layer on to another support and to develop the image by washing away the pigment that was the bottom of the film. Photographic Emulsions. If, to a solution of potassium bromide we add an equivalent amount of a solution of silver nitrate, we obtain a precipitate of silver bromide which quickly collects in the form of large flocks and settles to the bottom of the vessel. If the precipitate in this state or after washing, is shaken up with a solution of gelatin containing a trace of potassium bromide, a colloidal solution of silver bromide is obtained®. Such solutions are usually termed emulsions, though, strictly speaking, this is a misnomer they are suspensions, in which gelatin acts as a protective colloid. If the silver bromide is allowed to stand for two or three days before treatment with the gelatin and bromide, it will not form the emulsion. The usual method of preparing emulsions is to precipitate the silver bromide in the presence of gelatin. .The particles in the emulsion as soon as they are prepared, are very fine indeed, and such emulsions are sometimes called grainless. If the emulsion is washed free from dissolved salts at any time and kept at ordinary temperatures it becomes fairly stable, that is to say it changes fairly slowly or not at all. If there are dissolved salts present, which have a slight solvent action on the silver bromide, an increase in the size of grain takes place. The change is favoured by rise of temperature. The grains become more sensitive to light as they grow. This growing of the grains is called ‘“ripening.’”’ Under suitable conditions the grains grow by capilliary forces until they are 2u to 10u diameter!*. The smaller grains being more soluble than the larger, dissolve and make the solution supersaturated with respect to the larger ones which therefore grow. Usually crystals will only grow in this way until their diameter is about 2u, because above this size the solubility no longer diminishes as the size increases. The erystals of silver bromide can certainly grow to 10u diameter during ripening, and this may be due to the fact that such crystals are in the form of very thin plates (less than lu thick), or it may be caused by unequal heating and the presence of convection currents in the solution during ripening. The chloride and bromide of silver crystallise in the cubic systems at all temperatures used in the preparation of photographic emulsions. The iodide crystallises in the hexagonal system below 146° C., and above that temperature in the cubic system. The three halides _ form solid solutions with each other, so that in an emulsion containing more than one halide, we have only one kind of mixed crystals present. Although in many plates several per cent. of silver iodide is present 76 with the silver bromide we only get crystals of the cubic system. A microscopic examination of ripened emulsion shows that the particles vary in size from 0-4 to about 10u, but emulsions used in practice do not often contain crystals larger than from 2-3y. It is difficult or almost impossible, to determine the shape of particles smaller than 0-84 in diameter, but all particles of this size and larger are found to be forms of the cubic system, principally hexagonal and triangular plate and tetrahedra. Since there is no sharp break in the properties of an emulsion at any particlar size of particle, it is probable that even the smallest particles are crystalline. There is no evidence of the existence of amorphous silver bromide. When crystals of silver chloride are grown from an ammoniacal solution, cubes are formed, if gelatin is present there seems to be a tendency for the 1.1.1 faces of the crystal to develop. The simple cube does not seem to be formed in the presence of gelatin. When light shines on the silver halide a red coloration is produced. Luther showed that the halogen was liberated, and that the reaction did not take place if the pressure of halogen present exceeded a certain equilibrium value depending on the intensity of the light. These. coloured halides are often called photohalides, they may also be prepared by subjecting a mixture of finely divided silver and silver halide to a high pressure. It was formerly considered that these photohalides consisted of silver subhalides. The work of Sichling, Lorenz und EHitel, and Lorenz und Hiege has, however, conclusively proved that these photohalides are colloidal solutions of silver in the halide. Sichling showed by E.M.F. measurements that if silver sub- bromide existed at all in the halides, it was only to a very small extent, and was only stable over a very short range of concentration. The existence of colloidal silver in the photobromide of whatever composi- tion was definitely established. Lorenz and his co-workers showed that optically clear silver halides may be prepared by treating the fused salt with the halogen. When these optically clear crystals are exposed to light they darken, but remain at first optically clear, later the surface at which the beam enters becomes brown and the particles become visible in the ultra-microscope. The particles grow rapidly in the light, and will continue to grow if they are removed from the light and heated to 350° C. Heating without previous exposure to light does not produce these particles. The growth of these particles is accompanied by a diminution of coloration in the immediate neigh- | bourhood. The effect is evidently due to the separation of colloidal | silver in the metallic form. The analogy between these fogs and the metallic fogs formed in fused salts seems to be complete. It is probable that the latent image in the photographic plate consists of a colloidal solution of silver in the halide, and is the first stage of © the formation of the photohalide. Many theories of the latent image have been put forward, among which may be mentioned that of H. 8. Allen, who has suggested that the latent image is due to the loss of an electron by a molecule of the silver’ halide and the electron remains embedded in the gelatin. Under certain circumstances the electron may get back and the latent image may be destroyed. This, and many other theories have never been put to the proof. Some- — —_—™ ; 77 times it is difficult to devise experiments which will decide between various theories, all of which have been made as wide and indefinite as possible and consequently of little practical use. A deeper know- ledge of the latent image can only be obtained by further experiments to test the various theories. When silver bromide is precipitated by the addition of a soluble silver salt to potassium bromide in the presence of gelatin a colloidal solution is obtained. If the concentration of the silver salt added to the gelatin solution of potassium bromide is strong, the resulting colloidal solution appears blue by transmitted light®, *%, 7. Such emulsions are sensitive to red and even infra-red light. In the ordinary way emulsions are prepared from a dilute solution of silver nitrate, the emulsion thus obtained appears red by transmitted lights On ripening the colour changes to green. We do not know the size of the particles in the blite emulsion, they are probably very small. The red emulsion contains particles up te about 0-1 in diameter, the green emulsion contains particles from +54 upwards. In the blue and red emulsions the colours are quite well accounted for by the Rayleigh theory of the scattering of light by small particles, but as yet there is no explanation of the cutting off of the red end of the *spectrum by the emulsions with particles of about the diameter of a wave-length of light. Keen and Porter have shown that a similar colour change takes place in a suspension of sulphur when the size of particle becomes a little greater than the wave-length of light. BIBLIOGRAPHY. Preparation of Emulsions. ; - 1 Abney, Sir William (Piper & Carter, London, 1883). ‘ Photography with Emulsions.’ . 2 Eder, Handbuch der Photographie, Vol. III. 3 British Journal of Photography, 275, 286, 300 (1917). 4 Liesegang, R. E., Zeit. Phys. Chem., 75, 374 (1910). ‘ Uber die Reifung von Silberhaloidemulsionen..’ ; > Bancroft, Wilder D., Jowr. Phys. Chem., 14, 12, 96, 201, 620 (1910). ‘ The Photographic Plate.” The Emulsion, Pt. I., II., III., IV. These papers give an excellent summary and extracts from the literature of the subject up to 1910. 6 Luppo-Cramer, Phot. Korr., 44, 572 (1905). Theories of Ripening and the Latent Image. ? * Photohalides of Silver.’ Carey Lea, Sill. Am. Jour., 8, 33, 349, 476 (1887) ; Sill. Am. Jour., 3, 38, 129, 237, 248 (1889). 8 W. Ostwald, Eder’s Jahrbuch fur Photographie (1897), 402. __ *R. Luther, Zeit. Phys. Chem., 30, 628 (1899). * Studien uber umkehrbare chemische Prozesse.’ 10 R. Luther, Die Chemische Vorgange in der Photographie (1899). 11 Thiel, Zeit. Anorg. Chem., 24, 32 (1900). ‘* Formation of Mixed Crystals of _ the Halides of Silver.’ a 12 Monkemeyer, Jahr. Min. Beil., 22, 1 (1906). 4 18 Bellach, Wilhelm Knapp, Halle (1903). ‘Struktur der Photographischen _ Negative.’ f M Quincke, Hder’s Jahrbuch fur Photographie (1903), 3. 15 W. D. Bancroft, Jowr. Phys. Chem., 12, 209, 318, 417 (1908); 18, 1, 181, 269, 499, 538 (1909); 14, 292 (1910), * The Electrochemistry of Light.’ 4 7 " i 78 16 Luppo-Cramer, (Theodor Steinkopf), Dresden (1908). § Koloid-Chemie und Photographie.’ Several papers are published each year on this subject by Luppo-Cramer in the Kolloid Zeitschrift. 17 Sheppard & Mees, Zeit. f. wiss. Phot., '7, 27 (1909). ‘ Theorie der Photo- graphischen Prozesse: Reifen und der Photoelektrische Effekt.’ ; 18 A, P. H. Trivelli, Zeit. f. wiss. Phot., 8, 17 (1910). ‘ Beitrag zu einer Theorie des Reifungsprozesses der Silberhaloide.’ 19 Sichling, Zeit. Phys. Chem., 77, 1 (1911). ‘Uber die Natur der Photo- chloride des Silbers und deren Lichtpotentiale.’ 20 W. D. Bancroft, Jour. Phys. Chem., 15, 313, 551 (1911); 16, 27, 89 (1912). ‘The Photographic Plate’: The Latent Image, Pt. L, U., I1., IV. A summary of the literature up to that date. 21 Allen, The Photographic Journal, 54, 175. ‘The Formation of the Latent Image.’ 22 Lorenz und Eitel, Zeit. Anorg. Chem., 91, 57 (1915). ‘ Uber Silbernebel in Silberchlorid und Silberbromid.’ 23 Lorenz und Hiege, Zeit. Anorg. Chem., 92, 27 (1915). ‘Uber den Belichtungsvorgang in festen Silberchlorid und Silberbromid.’ 24 Krohn, Phot. Jour., 58, 179 (1918). ‘The Mechanism of Development of the Image in a Dry Plate Negative.’ 25 Ritz, Oewvres de Ritz, 4, 80. ; 26 Abney, Phil. Trans., 171, II., 653 (1880). ‘The Photographic Method of Mapping the least Refrangible end of the Solar Spectrum.’ 27 Ritz, Comptes Rendus, 148, 167 (1903). ‘ Sur la Photographie des Rayons* infrarouge.’ References to the papers on optical properties of colloidal solutions are given under the next section. Colloidal Silver and the Colour of Silver Deposits. : Colloidal solutions of silver in the finest state of division are yellowish brown in colour and as the size of the particles is increased the colour changes to ruby red, lilac, and blue. When these solu- tions are precipitated by the addition of an electrolyte a dark grey precipitate of silver is obtained. If a soluble silver salt is reduced by a powerful reducing agent such as alkaline pyrogallic acid, silver is precipitated in the black form, if a less powerful reducer such as pyrogallic acid alone, is used, a grey precipitate is obtained’. Any circumstance which tends to prevent the coalescence of the reduced silver such as the reduction of an insoluble salt, or the - enclosure of the salt in gelatin, yields the dark modification. Collodion does not hinder the coalescence of the silver particles to nearly the same extent as gelatin?. The colour of the image obtained varies to some extent with the developer used. If gaslight paper is developed with an excess of bromide in the developer the first image becomes red, but appears black as the develpoment proceeds. The products of oxidation of some developers stain the gelatin yellow or brown as these oxidation products are present in the greatest concentration at those parts of the plate which have been most exposed, the silver deposit in the negative appears to be stained through, though this is not the case. 1 Luppo-Cramer, Zeit. f. Chemie und Ind. der Kolloide, 3, 33, 130, 170 (1908). ‘Uber das Silbergel in den photographischen Schichten.’ ‘ 719 * Rayleigh, Proc. Roy. Soc., 84, 25 (1910). ‘The Incidence of Light upon a Transparent Sphere of Dimensions comparable with the Wave-length.’ * Chapman Jones, Phot. Jour., 51, 159 (1911); 57, 158 (1917). ‘On the relationship between the size of particles and the colour of the image.’ 4 Nils Philbad, Zeit. f. Chemie und Industrie der Kolloide, 9,156 (1911). ‘ Zur Kenntnis der Lichtabsorption in Silberhydrosolen.’ ®°Swen Oden, Zeit. Phys. Chem., 78, 682 (1912). ‘ Beziehung zwischen Teilchengrésse und Stabilitaét disperser Systeme.’ 6 Keen and Porter, Proc. Roy. Soc., 89, 370 (1914). ‘ Diffraction of Light by Particles comparable with the Wave-length.’ ? Paris, Phil. Mag., 80, 459 (1915). ‘On the Polarisation of Light scattered by spherical metal particles of Dimensions comparable with the Wave-length.’ § Gans, Ann. d. Physik, 47, 270 (1915). ‘ Uber die Form ultramikroskopischer Teilchen.’ ® Liesegang, R. E., Zeit. wiss. Phot., 14, 343 (1915). ‘ Uber die Polychromie des Silbers.’ 10H. F. Burton (Longmans, Green & Co., London) (1916). ‘The Physical Properties of Colloidal Solutions.’ 1 Rayleigh, Phil. Mag., 35, 378 (1918). ‘Scattering of Light.’ 2 W. D. Bancroft, Jour. Phys. Chem., 22, 601 (1918). ‘ Colour of Colloids.’ 13 Haas, Ann. d. Physik., 57, 7, 568 (1918). ‘ Die Beziehungserscheinungen, welche an einer grossen Anzahl unregelmissig verstreuter Offniingen oder undurchlassigen Teilchen auftreten.’ : Gelatin. In the dry plate the gelatin is not only a protective colloid for the preparation of the emulsion, an adhesive substance for attaching the sensitive substance to the glass and a photochemical sensitiser _ of the silver halide, but it plays a most important part in development. _ Unless gelatin, or some other colloid, is present, strong reducing agents such as alkaline developers will reduce silver halides without previous exposure to light. In presence of gelatin, however, this reaction is extremely slow!. The oxidation products of developers usually tan the gelatin— make it less soluble so that an ordinary negative shows the pictures in relief. The parts containing most silver being lowest, and the clear gelatin projecting to the greatest height’. Sheppard and Elliot have given an explanation of the reticulation of the surface of photographic negatives. Their explanation is based on Procters’ work on the effects of acids and alkalis on the swelling of gelatin??. The colloid chemistry of gelatin is discussed in detail by Procter in the First Report. The most important later work on the subject is that of C. R. Smith, who has studied the mutarotation of gelatin. He showed that gelatin in solution may be in a sol form A, stable above 35° C., or a gel form B, stable below 15° C. Between these _ two temperatures the two forms eventually come into equilibrium and this causes mutarotation. Form B is much more viscous than form A, and a certain definite concentration of B is necessary to _ produce gelatinisation. The authors’ experiments show that probably two molecules of the A form combine to form one molecule of the -B form. 1W. Reinders & J. van Niewenburg. Koll. Zeit., 10, 36 (1912). ‘ Gelatine und andere Kolloide als Verzogerer bei der Reduktion von Chlorsilber.’ ‘ * Lumiere & Seyewitz, Bull. Soc. Chim., iii., 85, 14 (1906). * Sur la composi- tion de la gélatine insolubilisée spontanément dans 1’ obscurité.’ ee 80 3 Lumiere & Seyewitz, Bull. Soc. Chim., iii., 88, 1032 (1905). ‘Sur la composition de la gélatine impregnée de bichromate de potassium insolubilisée par la lumiére et sur la théorie de cette insolubilisation.’ 4 Lumiere & Seyewitz, Bull. Soc. Chim., iii., 85, 676 (1906). ‘ Action des alums et des sels d’alumines sur la gélatine.’ ® Lumiere & Seyewitz, Bull. Soc. Chim., iii., 85, 377 (1906). ‘Sur le phénoméne de Vinsolubilisation de la gélatine dans le développement et en particulier dans l'emploi des révélateurs a lacide pyrogallique.’ 6 Lumiere & Seyewitz, Bull. Soc. Chim., iv., 1, 428 (1907) ‘Sur Vinsolu- bilisation de la gélatine par la quinoine.’ 7 Lumiere & Seyewitz, Bull. Soc. Chim., iv., 8, 743 (1908). ‘Sur les phénoménes de la précipitation et de Vinsolubilisation de la gélatine.’ 8 Procter, Transactions of the Chemical Society, 105, 313 (1914). ‘ Equilibrium of dilute hydrochlorie acid and gelatin.’ : 9 Procter, British Association, First Report on Colloid Chemistry and its Industrial Application, 24 (1917). ‘ Colloid Chemistry of Tanning.’ 10 Sheppard & Elliot, Brit. Jour. Phot., 65, 480 (1918). ‘ The Reticulation of Gelatin.’ 110, R. Smith, Jour. Am. Chem. Soc., 41, 149 (1919). ‘ Mutarotation in gelatin and its significance in gelatinisation.’ Gum. Gum is used in the gum bichromate process as the base of a pigment process just as gelatin is used in the carbon process, but a very thin layer of the colloid is used so no transfer is necessary. The gum is made insoluble by exposure to light after sensitisation with a bichromate. Gum arabic is generally used in this process. Starnes states that better results are obtained by the use of gum senegal. Starnes has made some experiments from which he concludes that when bichromate is added to the gum it is at once rendered less soluble. On exposure to light it first becomes quite soluble and then, on further exposure more and more insoluble. Thus in the early stages, of printing there is a reversal of the image. The phenomenon has, however, not been investigated quantatively. Starnes, The Photographic Journal, 42, 287 (1918). ‘The gum-bichromate process with a new colloid.’ COLLODION IN PHOTOGRAPHY. By H. W. Greenwoop, Research Chemist to The Leto Photo Materials Co. (1905), Ltd. The use of collodion has been coincident with the rise and progress of photography—by collodion is here meant a solution of pyroxylin in ether alcohol. Any discussion of the colloid chemistry of collodion apart from other forms of nitro-cellulose is almost an impossibility, for although — a great volume of work has been done, only a very small part of this — may be claimed as appertaining solely to collodion. The role of collodion in photography is similar to that of gelatine. It acts as a protective colloid, as a support, and also at times plays a part in the actual reactions. The greatest difference between collodion and gelatine is that collodion, except to a negligible degree, does not act as a sensitiser. Its insolubility in water, comparative 1 = 81 indifference to temperature, and its chemical inertia, are in marked contrast to gelatine, and are the main characters which render it of such importance as a support. Any discussion of the photo-chemical reactions involved in the preparation or utilisation of collodion plates or papers would be redundant, as they are of the same general character as occur in all photographic processes, and are dealt with elsewhere. A very full account of the history and preparation of collodion and its application to photography will be found in Vol. 2 of Worden’s * Nitro-cellulose Industry,” 1911, pages 827 to 897, where copious references are given to both patents and literature. Very little exact information exists as to the specific characteristics of photographic collodion. It is obvious that the character of any solution will depend upon the nature of the nitro-cellulose used, the solvents being under comparatively perfect control. The exact nature of the nitro-cellulose depends upon two factors, namely, the raw material used for nitration, and the constitution of the resultant nitro-cellulose, which latter naturally depends upon conditions and details of the nitration process. The permissible nitrogen content for the production of a photographic collodion lies somewhere between 11 per cent. and 12 per cent., and generally about 11-5 per cent. It is found that quite small variations of nitrogen content may involve large variations in physical character, such as, refractive index, viscosity, water compatibility, &c. Hence the mere nitrogen content, within the limits mentioned, does not in any way constitute a guide as to the suitability, or otherwise, of a nitro-cotton. Many attempts have been made to devise methods which would yield more positive results, but with comparatively small success; the behaviour of the nitrated fibre towards polarised light has been investigated by several workers, and a rough indication of the degree of nitration of the cotton can be obtained in this manner. The greatest value of the method so far is that it clearly differentiates, first, unnitrated fibres; and second, fibres of varying degrees of nitration. It is now realised that the usefulness of polarised light will be greatly extended when the results obtained by its use are correlated, not only with the nitrogen content, but with the physical properties, such as viscosity, refractive index, &c., which are of much greater significance than the nitrogen content in determining the properties of the collodion as far as its photographic utility is concerned. The lack of knowledge as to the constitution of the nitro-cellulose molecule is a bar to more exact information regarding the behaviour of nitro-cellulose solutions, as collodion, in the various processes for for which it is used in photography. Results of an anomalous character are frequent in all investigations, and although there is now -available a large volume of observations, they cannot yet be exactly correlated, nor is the information available which explains their occurrence. The effect of drying the cotton before nitration, and especially the temperature and treatment to which it is subjected before the actual nitration takes place, has a profound influence on the physical properties of the resultant nitro-cellulose. Further, both time and temperature modify the nitrated cotton. It would appear that all nitro-cottons undergo a process of denitration to a a 11454 F 82 greater or lesser degree, and that this denitration explains the anomalies that are so frequently met with in connection with the viscosity of collodions, and also with the behaviour of different films from one and the same solution. This decomposition is capable of acceleration not only by temperature but by many chemical agents; and also, probably takes place spontaneously at ordinary temperatures. The action of bromides in causing denitration is well known. One aspect of this phenomena is its importance in relation to the question of the keeping properties of collodion plates and papers, and of the permanence of the photographic image, whether negative or positive after the usual processes of development, fixation, &c., and in this direction much further investigation is called for. CELLULOSE ESTERS. By Foster Sproxton, B.Sc., F.L.C., Chief Chemist to the British Xylonite Co., Ltd. The technical problems which arise in any colloid industry naturally depend on the uses to which the finished material is put, and in view of the varied nature of the applications of such products as leather, glue, starch, explosives, and colloidal metals, it is not surprising that each industry is concerned with a somewhat different aspect of the chemistry and physics of highly disperse matter. The industry of the cellulose esters has for its principal object the manufacture of a material of valuable mechanical properties. Its colour, transparency, surface, &c., though of great importance, would be of little moment if the material did not possess elasticity, tensile strength, and toughness at ordinary temperatures, and plasticity at higher temperatures. The object of the industry is the provision of a material combining these properties without prejudice to its adaptability for artistic and imitative effects. It must be admitted that in the case of celluloid a high standard of technical excellence has been reached without the assistance of theories of the nature of the plastic material. The reproduction of material possessing the desired properties is accomplished only by strict control of the raw and semi-manufactured material, and close adherence to the conditions ascertained by experience. A brief account of the manufacture of celluloid will be found in Thorpe’s “ Dictionary of Applied Chemistry,’! to which the reader is referred. The manufacture of plastic materials from acetyl cellulose is described by Worden.? The colloidal problems encountered in the two manufactures are very similar except in the case of the preparation of the starting materials, nitro-cellulose and acetyl cellulose. These will be considered separately. Nitro-cellulose is made, as is well known, by the action of a mixture of sulphuric and nitric acids on eellulose, usually in the form either of cotton or paper. The two phases, solid cellulose and liquid acid mixture, persist throughout. It has been shown by Cross, Bevan, and Jenks, and by Hake and Lewis, that there is an intermediate formation of sulphuric esters of cellulose, which are gradually converted ~~ 83 almost entirely into nitric esters. Leaving this complication out of account, however, it is evident that the reaction must proceed by the diffusion of the acid mixture through the fibre. The final degree of nitration reached depends principally on the composition of the acid mixture, and nitrocelluloses of all percentages of nitrogen from 10 to 13 occur in commerce. From what has been said it is evident that the nitration process is very complicated, and it is not to be wondered at that it has not been brought to mathematical expression, although a vast amount of data has been accumulated’. However, by the accurate control of the composition of the bath, the purity and humidity of the cellulose, the temperature and time of nitration, very uniform products are obtained, and, to take only one instance, that of the manufacture of guncotton, the accuracy of modern musketry and artillery practice proves how uniformly a two-phase reaction can be controlled, although involving diffusion through a membrance which itself alters during the reaction’. Acetyl-cellulose is prepared by the prolonged action of acetic anhydride, acetic acid and sulphuric acid on cellulose, but the process differs from nitration in that the product is soluble in the reaction mixture. In this case, therefore, the acids reach the cellulose by diffusion through a gel of acetyl cellulose in acetic acid. The final product of the reaction is homogeneous, at any rate down to ultra- microscopic limits, and the acetyl-cellulose is recovered in the solid state by precipitation with water. The acetylation of cellulose takes much longer than nitration, and up to the present the uniformity of the product is inferior to that of nitrocellulose. This is probably due partly to the difficulty of temperature control, and partly to the complications introduced by modifications designed to produce material soluble in special solvents®. The central point in the manufacture of celluloid and acetyl- cellulose plastic materials is undoubtedly the gelatinisation of the base. Nitrocellulose retains the form of the original cellulose, although harsher to the touch. When it is kneaded with camphor and alcohol it is converted into a transparent gel, and the remaining processes of the manufacture merely consist in manipulating the gel while it is slowly hardening through loss of aleohol and part of the camphor. It is rolled out into sheets, pressed into blocks, sliced on a planing machine, and finally polished if required. The treatment of acetyl-cellulose is similar in principle, although different solvents are employed. . During the evaporation of the volatile solvents from celluloid in its seasoning or drying stage, there is a gradual loss in weight, diminu- tion in volume, and increase in specific gravity. It may be noted in passing that the specific gravity of celluloid is of particular interest to the manufacturer of celluloid articles, since he buys the material by weight, and, in effect, sells it by volume. The relation of the loss of weight to the loss of volume was investigated by the writer in relation to another technical problem. The extreme cases would be that of : (1) a sponge-like structure which could lose weight without (apparent) loss of volume in which case loss of weight/loss of volume = © ; (2) a structure which could shrink in volume without loss of weight, ; F2 84 in which case loss of weight/loss of volume = 0. On a priori grounds, therefore, any value for this ratio (which is the apparent specific gravity of the alcohol and camphor lost) might be expected. It was found in some careful experiments on a certain variety of celluloid in the final stages of drying that the ratio varied only from 0-82 to 0-91, the mean value for 28 samples being 0:87. This is the specific gravity of a solution of camphor in alcohol containing 42 per cent. of camphor by weight. Although these experiments do not prove that the shrinkage in volume of celluloid while seasoning is exactly equal to the volume of camphor and alcohol lost, they show that the difference, if any, must be small. There is no more fascinating branch of the technology of cellulose esters than the study of solvents. Hundreds of substances and mixtures of substances are known which have more or less marked solvent action on nitrocellulose or acetylcellulose, but the question of how to make a fair comparison between one solvent and another has never been completely worked out. The work was begun for nitrocellulose by the late F. Baker’. He came to the conclusion that the best solvent of a particular sample of nitrocellulose was the solvent which yielded the solution of lowest viscosity, and this is in agreement with manufacturing experience. It may be pointed out, however, that another method might be chosen, and that is to find the solvent yielding solutions which will bear the greatest dilution with an indifferent, miscible non-solvent, such as petroleum ether, before the cellulose ester is precipitated. This method is also in line with the technical valuation of solvents. and a rigorous comparison between the two methods would be most interesting. Petroleum ether has been suggested here as the indifferent liquid, because of the unexpected results sometimes obtained when mixtures of liquids-act on cellulose esters. It has been long known that ethyl alcohol and ether are, separately, non-solvents of soluble nitro-cotton, but form a solvent when mixed. This mixture was investigated by Baker*, and he concluded that the solvent power was exerted by a complex formed by the combination of ether and alcohol. This is a reasonable explanation of this par- ticular case, but it does not explain the extraordinary effect sometimes ‘produced on solvent power by the additions of quite small amounts of foreign substance. One instance which has long been known is the solvent power imparted to methyl alcohol by the presence of traces of acetone. A recent example of the technical application of the principle is Eng., Pats. 14,655 and 14,656, in which the addition of small quantities of substances such as nitro-toluenes, formanilide, &c., is employed to facilitate the solution of nitrocellulose in nitro- glycerine. But, returning to the consideration of mixtures such as ether- alcohol where each constituent is present in bulk, it would be of interest to extend Baker’s viscosity work on solvent power to such mixtures, and find what proportions of the constituents produced the best solvent mixture. Probably the records of such experiments exist, but they do not appear to have been published.—Index 9a. The results would be of value in a field somewhat remote from that of colloid chemistry, in view of the recent work of Bramley and others on binary 85 mixtures’. The viscosity/concentration curves of such mixtures usually show maxima, the positions of which vary with the temperature, and Bramley concludes that the viscosity of liquid mixtures as an inde- pendent test of compound formation in liquid mixtures is unsatis- factory. The writer suggests that the viscosity/concentration curves of mixtures of liquids containing a constant weight of a viscous colloid in solution might give more useful results. The viscosity of the solvent would be masked by the viscosity due to the colloid, dissolved, presumably, in a complex of the two liquids. It is certain that in many cases minima would be found, and it would be interesting to see whether these minima also shifted with change of temperature, and whether their position corresponded with molecular addition compounds. The method could be applied to all mixtures possessing solvent power for a viscous colloid, whether the constituents separately were solvents or not. For instance, mixtures of aliphatic alcohols and benzene hydrocarbons should be examined with nitrocellulose in solution, and mixtures of aliphatic alcohols and chlorinated paraffins with acetylcellulose in solution, and so on. Although the results obtained would be chiefly valuable as a contribution to the study of binary mixtures, they would also be useful data in the chemistry of emulsoid solutions’. The same question was encountered in a different form some years ago by the writer in a purely technical investigation. It is well known that ethyl alcohol and toluene together form a solvent for nitro- cellulose of low nitration. To find the composition of the best solvent, constant weights of nitrocellulose of imperfect solubility were treated with a constant volume of toluene and alcohol in different proportions and the amount of nitrocellulose dissolved by each mixture was estimated. The results showed that the optimum mixture corresponded closely with a mixture of three molecules of alcohol to one of toluene thus suggesting the existence of a complex C,;H;, 3C,H;OH. Regarded from the purely colloid point of view, perhaps, the development of solvent power by relatively small additions of other substances to partial or non-solvents is the more interesting owing to its analogy to organised processes such as nutrition. The nature of the solid camphor-nitrocellulose complex is still unknown. Schiipphaus"™ believes that there is some kind of chemical combination between camphor and nitrocellulose, chiefly on the ground that the heat of combustion of celluloid is less than that of its constituents. But this is only the complement of the fact that camphor and nitro-cellulose evolve heat when mixed, which cannot be regarded as evidence of chemical combination. The large changes in surface energy which must accompany gelatinisation would be sufficient to explain the thermal phenomena. The optical rotation of an acetone solution of camphor and nitrocellulose is equal to the sum of the separate rotations of the camphor and the nitrocellulose, within the limits of experimental error??. Dubosc1* expresses the following views on the constitution of celluloid. Celluloid is a “ camphrogel’’ of nitrocellulose, camphor being the dispersion medium. In the process of gelatinisation 86 solid nitrocellulose absorbs camphor present in the liquid phase (camphor and alcohol), forming a mass of gel cells enclosing a pseudo- solution of nitrocellulose in camphor and alcohol. The subsequent rupture of the cells during kneading and loss of alcohol by evaporation, leads to an enormous increase in viscosity. There is, however, in the case of camphor celluloid, no separation of suspensoid or solid phase, such as may happen with some of the substitutes of camphor. This is shown by milkiness or opacity in the celluloid, by brittleness and lack of plasticity in the working. The plasticity of camphor celluloid on heating to about 80° C. is attributed to the formation of a liquid phase by fusion, diminishing internal friction. , Dubosc admits that experimental evidence in support of these views is meagre, but on the whole they appear reasonable. Exception might be taken to regarding camphor as the dispersion medium when it occupies only about one third of the bulk of the celluloid. Speculations on the structure of cellulose esters and the plastic materials made from them inevitably lead to a consideration of the structure of cellulose itself. Cellulose has already been treated by other writers in these Reports'*, and a much-needed emphasis has been placed on its colloidal character. There are still chemists who write as if the elucidation of the structure of cellulose were a problem analogous to the determination of the formula of, let us say, brucine or dextrose. The underlying assumption appears to be that some day the suffix n in the formula (C,H,,O;) n will be determined, and then, given a sufficiently large sheet of paper, the complete formula will be constructed. It must be admitted that this assumption has led to much interesting research!. It is only natural that chemists should attempt to assign definite molecular weights to the materials they handle. The tendency probably arises ultimately from the extraordinary developments of theoretical chemistry on the basis of Avogadro’s hypothesis, culminating in the work of Vant’ Hoff. It may not be out of place to point out that of all the materials that we wear, handle and consume, those to which the methods of Vant’ Hoff can be applied are in a vast minority. Colloidal chemistry would be immensely simplified if it could be brought under systematic mathematical treatment, but in view of the vast differences in properties between the colloidal and crystalline states, it is unreasonable to expect to force colloids into the crystalline system. It is agreed on all hands that if cellulose and similar colloids have a definite molecule, its weight must be extremely large. But the larger the assembly of (C,H,,O;) units becomes, the more difficult it is to imagine what forces would come into play to put a sudden stop to the process of aggregation. In view of the continuous nature of plant growth, it is not to be expected that there should be a definite limit to the size of the cellulose aggregate, any more than there is to the size of a honeycomb. The limit to the aggregation of C, units is probably set, not by internal chemical forces, but by external conditions such as atmospheric temperature and humidity, and the vital activity of the plant—TIndex 14a. Wohler’s synthesis of urea was hailed as breaking down the barrier between organic and inorganic chemistry, but crystalline substances like urea 87 are not typical of vital processes. It is always in a colloid medium that the phenomena of life are manifested'*. Fischer’s synthesis of the polypeptides comes much nearer to an imitation of vital processes, and there appears to be no chemical limit to the application of the reactions he employed. A distinction should be drawn between efforts to determine the size of the cellulose molecule and experiments to determine the configuration of the C,H,,O; units. It may be remarked in passing that there is no reason to suppose that all the C,H,,0; units have the same configuration, and a quantitative conversion of cellulose to any particular sugar is unlikely’. Pictet and Sarasin’? by the dry vacuum distillation of cellulose obtained levoglucosan, and Sarasin has suggested that cellulose is built up from this unit?®. Owing to the drastic nature of the decomposition involved, the suggestion must be taken with some reserve, and Irvine has criticised it on other grounds’. It is interesting, however, to build up 1|-glucosan with the aid of tetrahedral carbon atom models, when it will be found that the carbon atoms 1, 2, 3, 6 and the oxygen atom are approximately in one plane, and the carbon atoms 6, 3, 4, 5 and the oxygen atoms 7 and 8 in another plane, approximately at right angles to the first plane (see formula in bibliography). The complex would therefore grow in three dimensions (an elementary detail which is sometimes over- looked), and groups and atoms would be brought into proximity in a way which would never be demonstrated by a diagram in two dimensions. One is tempted to speculate whether the insolubility of cellulose in water is due to this mechanical smothering of the hydroxyl groups by the growing complex, or even whether the hydroxyl groups really exist as such in solid cellulose?®. Certainly any reaction which degrades the cellulose complex yields a product which will take up more water than the original cellulose, and even long-continued mechanical grinding will yield a sticky or pasty mass; from which it appears that increasing the surface of cellulose increases its solubility in water. On the other hand, the vulnerability of cellulose to esterification without profound hydrolysis militates against this view. The chief contribution which the manufacture of celluloid makes to colloidal theory at the present time is in its insistence on the fundamental difference between emulsoids and suspensoids. There is a close connection between the viscosity of dilute solutions of cellulose esters, and the mechancial properties (or what is called in the rubber industry the nerve) of the solid product®!. So far as the writer is aware, neither suspensoid nor crystalloid solutions possess any physical properties which can be correlated with the properties of the solid derived from them by evaporation. In crystalloid and suspensoid solutions we have free particles—ions, molecules, or aggregates—moving independently of each other in the dispersion medium. But in emulsoid solutions, as exemplified by cellulose esters, we find a manifestation, in a reduced degree, of the same forces that produce “ nerve ” in the solid form. Therefore the disperse phase cannot consist, at any rate entirely, of particles having independent existence in the dispersion medium. There &8 must be structure, and perhaps the most reasonable assumption is a form of network in three dimensions, the interstices being filled either with pure solvent or with solvent containing disperse phase in a lower state of aggregation. There are admittedly difficulties in such a hypothesis, e.g., in regard to the equilibrium between the two concentrations co-existing?’. This view of the viscosity of ° nitrocellulose solutions draws a distinction between them and the highly viscous solutions of such crystalline substances as cane sugar in water, which may be regarded as owing their viscosity to the presence of large aggregates consisting of molecules of sugar surrounded by attracted water molecules. This suggests another contrast between the two. The attraction of sugar molecule for water molecules is regarded as being related to the high solvent power of water for sugar and also to the high viscosity of the solution. In the case of cellulose esters, as we have already seen, the best solvent is regarded as the one which gives solutions of least viscosity. In view of these considerations, a study of the transition from emulsoid to suspensoid solutions would be of great interest. It is well known that an alcoholic solution of mastic, if poured into water, yields a suspensoid solution of mastic. In a similar way a dilute acetone solution of nitrocellulose on dilution with water yields a suspensoid solution of nitrocellulose. From some incomplete experi- ments it appears that the gradual addition of water to the acetone solution, keeping the concentration of nitrocellulose constant, produces @ gradual rise in the viscosity of the solution, both absolutely and relatively to the viscosity of the solvent, until a maximum is reached, after which the viscosity falls until it almost coincides with that of the solvent. The Tyndall effect becomes marked close to the position of maximum viscosity. On the network view of the structure of nitrocellulose solutions these changes would mean a stiffening and probably a shrinkage of the network as the percentage of water in the solvent increases, and finally rupture into free particles, possessing a refractive index sufficiently different from that of the medium to show the Tyndall effect. Reference should be made to the analogy developed in text-books of physics between viscous stress in liquids and shearing stress in a strained elastic solid, according to which a viscous liquid is regarded as able to exert a certain amount of shearing stress, but is continually breaking down under the stress. The equation developed is 7 = n/A in which 7 is the co-efficient of viscosity, n the co-efficient of rigidity, and 1/A the time of relaxation of the medium, i.e., the time taken for the shear to disappear from the substance when no fresh shear s supplied to it. This is a much more illuminating way of regarding the viscosity of liquids than the analogy with gases, since the viscosity of liquids, unlike that of gases, diminishes with rise in temperature.?* But it is particularly suggestive in the case of solutions of colloids like nitrocellulose and rubber which depend for their value on their mechanical properties***. In the case of celluloid, in particular, we are dealing with what is at ordinary temperatures an elastic solid, and it would be most instructive to follow up its properties from dilute solution to the solid state, both with and without the addition of 89 camphor. The intermediate zone would offer considerable experi- mental difficulties, but the ground has already been broken by Trouton and Rankine”*. A complete examination of celluloid from this point of view would include the viscosity in dilute solution, gradually increasing the concentration until determination of Trouton’s coefficient of viscous traction became practicable, and finally the rigidity, bulk elasticity, and tensile strength as the celluloid gradually lost its solvent. In all cases temperature effects would have to be studied, and the comparison of rigidity and viscous traction at various temperatures would be of particular value in the case of finished celluloid, while the data as a whole could hardly fail to throw light on the problem of the structure of viscous colloids. REFERENCES. 1Vol. 1, p. 705 (1912 edition). The account given here is written by Schiipphaus. 2“ Technology of Cellulose Esters,’ Worden, Vol. VIII. 3 Cross, Bevan & Jenks, Ber., 34, 2496; Hake & Lewis, J.S.C.I., 24, 374 (1905). 4 See, for example, Lunge, J. Amer. Chem. Soc., 28, 527 (1901), and many others. 5 Nathan, J.S.C.I., 28, 177 (1909). Note particularly (p. 185) the small variation in nitrogen percentage (from 12-95 per cent. to 13-05 per cent. in a year’s work). ® See Miles, Eng. Pat. 19,330 of 1905, on the solubility changes induced by partial hydrolysis. An extensive list of patents is given by Worden, J.S.C.1., 38, 370 T (1919). ? Baker, Trans. Chem. Soc., 108, 1653 (1913). The viscosity of nitrocellulose in various solvents follows the empirical law 7=y, (1--ac)k, in which 7= viscosity of solution, 70 = viscosity of solvent, c = concentration, a and k are d logy. : constants depending on solute and solvent. The value of - ros 7 is convenient for comparing different solvents. 8 Baker, Trans. Chem. Soc., 101, 1409 (1912). From the viscosity concen- tration curves given by mixtures of ethers and alcohols, it appears that dissociation of the latter takes place in such mixtures, but this dissociation is probably . associated with the formation of an ether-alcohol complex, and to this complex the solvent power of these mixtures for nitrocellulose is due. ® Eng. Pats. 14,655 and 14,656 of 1915. (Rintoul, Cross, & Nobel’s Explosives Co., Ltd.) The additions are of the order of 0.1 to 1 per cent., and enable the mixture of nitrocellulose and nitroglycerine to be gelatinised without raising the temperature. % Since this report was written, an important paper on the subject has been published by Gibson & McCall, J.S.C.I., 89, 172-176 T, (1920). They find that the composition of the ether-alcohol mixture of optimum solvent power depends on the nitrogen content of the nitrocellulose. 10 Bramley, Trans. Chem. Soc., 109, 469 (1916). 108 Price (Trans. Chem. Soc., 115, 1116 (1919)) has shown that the abnormality of the volatility of cordite made with equal properties of acetone and ethyl methyl ketone is not due to any abnormality of vapour pressure or density of the mixed solvents. ; ? 1. Thorpe, Dictionary of Applied Chemistry, loc. cit. 12 Unpublished observation. Only dilute solutions have been examined. 18 Dubosc, Le Caoutchouc et la Gutta-Percha, 9803-9808 (1919). 14 Ist Report, King 20-38, Chrystall 82-84. 2nd Report, Harrison 54-61. 14 Gibson makes the same suggestion in a recent paper. Trans. Chem, Soe. 117, 482 (1920). 90 16 Cf. Boeseken, v. den Berg & Kerstjens, Rec. Trav. Chim. Pays Bas, 85, 320-345 (1916). Cellulose is regarded as (C;Hj,.Og)n—(n—1) H,O, and the acetylation process is studied. As the molecule is hydrosed the acetyl number increases from 62-5 for cellulose triacetate to 77 for dextrose pentacetate. The molecule combines with 3n+2 mols of acetic acid, giving a triacetate of molecular t 1,000 (3n+ 2) weight (162n+18)+(3n+2)42. The acetyl number = 48m 17 n can be calculated. Values of n as high as 47-5 were found. 16 The viscous colloids are nearly all of vital origin. Cf. gelatin, rubber, casein, the gums, etc. 16 See in this connection Miss Cunningham, Trans. Chem. Soc., 118, 173-181 (1918). 1” Pictet & Sarasin, Compt. rend., 166, 38-39, (1918). 18 Sarasin, Arch. Sci. Phys. Nat., IV., 46, 5-32 (1918). Starch and cellulose are polymerides of 1-glucosan. from which HO—CH: CHOH 1 2 HC&— O’—°CH | HAC’ O& 4CHOH Polymers are found by the opening of the oxygen atom marked 8. This explains the presence of 2-5 dimethyl furane in the products of decomposition. 19 Irvine, Annual Reports (Chem. Soc.), 69 (1918). The glucosan-polymeride formula is criticised on the ground that it does not account for the particular trimethyl glucose obtained from methylated cellulose by hydrolysis. (See Denham & Woodhouse, Trans. Chem. Soc., 111, 244 (1917)). 20 Compton (J. Franklin Inst., 185, 745-774 (1918)), concludes that in the solid state, atoms are so intimately intermingled that particular molecules cannot be said to have any real existence. 21 ng. Pat. 114, 304 (H. Dreyfus) states that the higher the viscosity of cellulose acetates, the greater the amount of plastifying or softening agents which can be incorporated, and the stronger the resulting material from every point of view. 22 Tn this connection see Bayliss, 2nd Report of this Committee. ‘ Protoplasm and Cell Contents,’ and ‘.The Nature and Permeability of the Cell Membrane.’ . 117-137. PP* sa J. D. van der Waals, jnr. (K. Akad Amsterdam, Proc. 21, 5 pp., 743-755, 1919) points out this difference between gaseous and liquid friction. He attributes liquid friction to the forces exerted by the molecules on each other, whereas in gases it is due to the transfer of momentum from one layer to another. 3 The resistance to shearing stress gradually increases as solvent is removed, until finally an elastic solid results. *4 Trouton, Proc. Roy. Soc. 77, 426 (1906) and Trouton & Rankine, Phél. Mag. [6], 8, 538(1904). In the stretching of rods of highly viscous material the following relation is found :— F /dv A/ dx —* Where F = stretching force. A = cross section of rod. v = velocity of given point of rod. x = distance of moving point from point of suspension. From a chemical point of view it is unfortunate that Trouton worked with substances of so indeterminate a nature as pitch and shoemakers’ wax. The use of a plastic material composed of a celluloid ester, a crystalline filler such as camphor, and alcohol, in a similar series of researches, would to some extent simplify the interpretation of the phenomena. We do not know yet why camphor is par excellence the solid solvent for nitrocellulose. It evidently possesses a somewhat unique combination of chemical and physical properties. Substitutes for camphor can only be accurately compared with it by some system of physical tests of the resulting material such as these. The explanation of its colloidal behaviour is not likely to be found until these experiments are done. 9] COLLOID CHEMISTRY OF PETROLEUM. By Dr. A. E. Dunstan, A considerable body of evidence is available concerning the colloidal nature of crude petroleum and some of its distillates. Crude oil of the paraffin base type (i.e., oil which on distillation yields solid paraffins in the high boiling fractions) usually contains colloidal amorphous matter which only assumes the crystalline state after distillation. It is probable that the effect of heat in this case is physical, bringing about a change of state whereby the wax is no longer in the dispersed condition characteristic of the original oil. Such oils and their residues after the removal of benzine and kerosene are frequently highly viscous, particularly at low temperatures, owing to the “setting” of the paraffin sol. This phenomenon may be demonstrated by immersion of a suitable residual oil in ice for several hours when the mass appears to be quite solid. A sudden jerk or violent shaking will destroy the quasi-solid mass and a thick clotted semi-fluid material will be formed. The black or dark coloured “asphaltic base” oils contain bituminous matter which is to be regarded as being derived from the petroleum hydrocarbons by oxidation (and sulphuration) and condensation. . These oils are optically heterogeneous, although in most cases the degree of dispersion is very high (see Holde, Koll. Zcits., 1908, 8, 270; Schneider and Just, Zeit. f. Wiss. Mikrosk, 1905, 22, 561). The colloidal asphalts may readily be coagulated by means of strong sulphuric acid (Schultz, Petroleum, 5, 205, 446). The chemistry. of the well known “ acid treatment ” has _ been investigated by B. T. Brooks and I. Humphrey (Jour. Amer. Chem. Soc., 1918, 40, 822). The usually accepted view that olefines are polymerised to tar and removed as sludge is erroneous, for pure olefines (up to the C,, member) do not give tars with acid up to 100 per cent. strength at 15° C. The formation of “acid tar” is probably a dual phenomenon—firstly, the acid coagulates the colloidal matter present in the oil; and, secondly, it brings about polymerisa- tion of olefines and diolefines, sulphonation of aromatic derivatives, together with oxidation of primary materials and products. Pyhala (Zeits. Chem. Ind. Koll., 1911, 9, 209) considers that crude oils are sols of which the disperse phases are solid gels such as asphalt, together with liquid particles. Separation may be achieved by means of centrifuging or the addition of electrolytes. When the disperse phase exceeds 60 per cent. the phenomenon of gelatinisation makes its appearance. ; In the discussion on a paper by Glazebrook, Higgins and Pannell (Jour. Inst. Petr. Techn., 1915, 2, 54 et seq) the writer brought forward the peculiar hysteresis effect in the viscosity of fuel oils and showed that by a suitable alteration in the previous history of a given oil, wide variations in its viscosity may be effected. The corresponding » behaviour in aqueous gelatine sols is well known and affords an interesting parallel, : 92 The colloidal asphaltic matter in crude oil and the yellow colouring matter in benzine, kerosene, and other distillates which is largely caused by “ tar-fog’”’ mechanically carried over, may be removed by coagulation (and solution) brought about by agitation with strong sulphuric acid. Direct adsorption on specific surfaces however, is equally effective. The writer has shown that floridin, Fuller’s earth, and bauxite which, when freshly ignited, possess powerful adsorptive action, follow the well-known exponential adsorption rule :— 1 Y/m = ac". For example, using a 0-25 per cent. solution of a crude asphaltic base oil in benzine as a test liquid, constant values of n were obtained and the Y/m — c curves were of the usual parabolic type. The application of the adsorptive action of these substances in the refining of various distillates is well known and much of the theoretical side has been admirably expounded by Day and his co-workers (Proc. Amer. Phil. Soc., 1897, 36, No. 154; Trans. Petr. Congress, Paris, 365; Gilpin and Cram, U.S. Geol. Survey Bull., 365; Washington, 1908; and Gilpin and Bransky, U.S. Geol. Survey Bull., 475, Washington, 1911. See also Richardson and McKenzie, Amer. Jour. Sci., May 1910; Richardson and Wallace, Jour. Soc. Chem. Ind., March 1912; Porter, Bull. 315 U.S. Geol. Survey, 1907). In brief, the following conclusions were arrived at :— (1) Fuller’s earth tends to retain the unsaturated hydro- carbons and sulphur compounds in petroleum, thus exercising a selective action on the oil. (2) When crude petroleum diffuses upwards through a column of Fuller’s earth a fractionation of the oil occurs. The oil displaced by water from the earth at the top of the tube is lower in density than that from the bottom of the tube. (3) The aromatic hydrocarbon in a mixture of a paraffin oil and benzene tends to collect in the lower end of the diffusion column. Gilpin and Schnerberger (Amer. Chem. Jour., 1913, 50, 59) consider that the Fuller’s earth behaves as a dialysing septum which allows paraffins and saturated hydrocarbons to pass freely but adsorbs bitumen, aromatic hydrocarbons, sulphur, and nitrogen compounds. The determining factor is surface. Similar views are propounded by Gurwitsch (Peir., 1912, 8, 65) who ascribes Day’s results not to capillarity but to specific surface adsorption. This author shows that floridin will adsorb solid paraffin from solution in petroleum spirit and benzol, but not from lubricating oil. An interesting observation was made by Herr (Peér., 1909, 4, 1284), who filtered Baku oil through fuller’s earth and discovered that all the formolite forming compounds were removed, i.e., the unsaturated compounds which react with formolin were adsorbed on the mineral gel. It by no means follows that the compounds which are adsorbed can be recovered unchanged. Being possessed almost invariably of residual affinity the close contact afforded in the adsorbed layer .« promotes condensation and polymerisation, and thus Gurwitsch i 93 (Jour. Russ. Phys. Chem. Soc., 1915, 47, 827) was able to show that floridin brings about active polymerisation when brought into contact with amylene and pinene, resulting in considerable rise in temperature. Curiously enough the same polymer, di-amylene, is produced both by sulphuric acid and by fuller’s earth. Pinene, similarly, is converted after adsorption into sesqui and polyterpenes.. Alumina behaves in the same way towards amylene, but is apparently without effect on pinene. The writer’s experience has been that freshly ignited precipitated alumina is particularly effective as a decolourising agent for petroleum and its distillates and a series of experiments using a 0-25 per cent. solution of crude asphaltic oil in benzene showed the following order :— c.c. of coloured solution Material (1 gram). decolourised. Alumina - : : : = f AGU Fuller’s earth I. - - : ee ad 2) 836 Bauxite I. - = : e : aopaath Bauxite II. - - . 2 E eS Bauxite ITT. - = A - 3 pie 4) Ignited peat B - E z 3 =e Ua) Bone charcoal - : - é Z Sate Bog iron ore - - eae ar : : Peis 16 Fuller’s earth II. - = “ é = Same Ferric oxide - - E : _ i e FLO Ball clay : : / m é 2 BR Fuller’s earth III. - - 2 2 Lantg Fuller’s earth IV. - - 4 . HM hig China clay - 1 : u Z j spre Kieselguhr_- ~ : : u u 47) 0g The temperature at which the adsorbing surface exerts its specific effect is of some importance. Gilpin and Schnerberger (Amer. Chem. Jour., 1913, 50, 59) on passing Californian crude oil through fuller’s earth found little fractionating effect at 20° C. but a satisfactory result at 70° C. A peculiar observation made by the writer is of interest in this connection. Cold bauxite, which has been ignited and cooled in a vacuum desiccator was found to have lost its power of adsorbing sulphur derivatives from kerosene. When freshly heated (to 200° C.) its activity in this direction was regained. Heat appears to be evolved during active adsorption, thus a 20° C. rise in temperature was observed during the passage of 100 c.c. of kerosene through 50 grams of bauxite. Amongst other effective materials may be mentioned Kambara earth (Kobayashi, Jour. Ind Eng. Chem., 1912, 4, 891), a mineral containing hydrated silica, which decolourises crude petroleum and adsorbs unsaturated hydrocarbons therefrom. Fibrous alumina has been recommended by Gawolowski (Allg. Oesterr. Chem., 1908, 26, 87), whilst animal charcoal and prussiate residues have long been employed for these purposes. 94 Naturally the degree of fineness of the adsorbent is. important. The following case will illustrate this point :— Bauxite Mesh. Activity. 40/60 —s- - - - - - - - 1-0 60/80 - | - - : c : 3 (eee In point of fact the activity—all experimental conditions being the same—is approximately directly proportional to the mesh. A con- venient method of demonstrating this point consists in treating a 100 c.c. of coloured solution (as e.g., that already mentioned) with varying weights of decolourant, matching the filtered resultant solution with the standard solution in a Nessler jar (C. ¢.cs.) and plotting = = ass against C. Ordinates at C = 50 give directly the reciprocals of the masses required to remove 50 per cent. of the colour. Thus with floridin :— Mesh. Mass. Passing 180 - - - - - - - 50/320 Passing 80 and retained on 180 - - - - 60/170 Passing 20 and retained on 30 - 7 - - 50/44 and with Bauxite Passing 80 - - - - - - 50/175 Passing 60 and retained. on 80: - - - - 50/80 Passing 20 and retained on 30 - - - - 50/30 Little can be said as to the relationship between the chemical composition of the material and its adsorbent properties. Apparently hydrated silica or alumina is effective after combined water is expelled, but no general statement can be made. Substances giving the same analytical figures may behave quite differently, and again, bodies of dissimilar chemical composition may be equally effective as decolour- ising agents. The essential feature of all effective adsorption agents is develop- ment of surface, hence mineral gels containing water of combination which, on ignition, possess a characteristic structure are decidedly likely to possess decolourising and desulphurising properties. Very characteristic is the behaviour of bauxite (say, 40/60 mesh) on being gently agitated with kerosene or benzene. Apparently a process of peptisation goes on, for a considerable amount of very finely divided material separates in suspension in the petroleum, and is sufficiently fine to pass readily through filter paper (see W. Bancroft, Vol. II. Report on Colloid Chemistry, 1918, page 2 et seq). A highly important contribution to the application of colloid chemistry to industry was made by Clifford Richardson (“‘ The Modern Asphalt Pavement ”’ and reprint of a paper read before the St. Paul Engineering Society, 1917). This investigator showed that the durability of anasphalt pavement is directly connected with the fine- ness of the mineral aggregate, 7.e., with the extent of the surface developed. The capacity factor of the surface energy is measured by the absolute surface displayed and the intensity factor by the particular surface tension of the materials employed. As a case in point, a —_— en 95 particular pavement laid in 1895, the surface of the aggregate was 44 square feet per lb. of material, whereas in a later one the surface was iucreased to 60 square feet per lb. The former pavement was unsatisfactory, and the latter was excellent. Naturally occurring colloidal suspensions are found in Trinidad, where the asphalt contains 25 per cent. of finely divided mineral matter, but artificial mixtures of bitumen and dispersed clays can be made which may contain as much as 60 per cent. of mineral. The various asphalts (natural and artificial) possess different powers of retaining the disperse phase. Broadly speaking, asphaltic residues from crude oils are inferior in this respect to the natural bitumens. Miatures of 67 per cent. Bitumen and 33 per cent. Clay (introduced while wet) and maintained at 325° F. for 24 hours. Colloidal Matter. Source of Bitumen eae lo ee ; Before After tion. heating. heating. per cent. per cent. per cent. Trinidad residue : - - - 33-5 33-7 0-0 Badabin ,, - - - - 32-4 30-1 7:0 Mexican be - - - - 33°3 27-2 18-3 California ,, 2 - - - 31-8 23-8 25-2 Mid Continental residue - - — = — Semi-paraffin A - - - 33-8 21-7 35°8 The temperature 325° F. is that at which is formed the film of bitumen which covers the mineral aggregate of a sheet asphalt pavement. It is striking that the Trinidad residual is so thoroughly differentiated from all the others, confirming the opinion based upon service tests in regard to the unique character of this material. Although in actual refining operations the adsorptive properties of the materials described above have mainly been directed towards the removal of colour, yet considerable success has been achieved in connection with the equal important problem of desulphurisation. It by no means follows that an adsorbent is equally effective in removing colouring matters and sulphur derivatives. Usually this is not the case, and each material must be tested for its specific purpose. So far as the writer’s experience goes, the sulphur compounds present in the lighter distillates are more readily adsorbed than those in the higher boiling fractions, although it is possible that in the latter case there is preferential adsorption of other substances, e.g., unsaturated hydrocarbons. Whilst for example, floridin will desul- phurise benzine quite readily, it has little effect on the sulphur compounds which occur in the lubricating oils derived from the same crude petroleum. An interesting application of adsorption is to be seen in the method patented by Hall Motor Fuel, Ltd., for the purification of cracked 96 spirit. This material, as is well known, contains a considerable proportion of highly unsaturated hydrocarbons—olefines and diolefines —to the presence of which it owes its characteristic odour and its objectionable propensity towards resinification or “ gumming.” Although the reactive hydrocarbons can be removed by the agency of strong sulphuric acid, the operation is attended by serious loss, but by utilising the adsorbent capacity of floridin, the diolefines present are polymerised to high boiling products and a spirit free from objection is produced. The refining operation is best carried out with the spirit in the vapour state, under these conditions adsorption is followed by condensation and/or polymerisation. Incidentally the sulphur derivatives present in many , benzines and kerosenes may be removed in a precisely similar manner, The problem of the breaking of persistent emulsions in refining operations is obviously one for treatment by the application of colloid chemistry. The soda wash which is employed to remove the traces of sulphuric acid in the refining of lubricating oils is a common source of this trouble and in some cases a practically permanent emulsion isformed. The sodium salts of naphthenic and sulphonated naphthenic acids are notable emulsifying agents and it is possible that hereinlies the cause of what is sometimes a serious difficulty. Itis interesting to remember that sodium naphthenates are used very extensively as soap. A recent patent by Southcombe and Wells brings out the novel point that a small amount (1 per cent.) of free fatty acid added to a mineral lubricating oil, not only replaces the usual blending fatty oil, but according as its molecular weight is low or high, yields a non-emulsifying or an emulsifying oil. It appears that the addition of the free fatty acid appreciably lowers the interfacial tension between the lubricating oil and the bearing. 29 Petroleum jelly or “ vaseline ” appears to be an emulsion of soft paraffins dispersed in heavy oils. The viscosity increases gradually with decreasing temperature until the gel state is attained, without, however, any separation of crystalline wax, but on being distilled, wax appears in the distillate. Various artificial jellies are on this market, being com- pounded of soft wax and heavy oil, these, on the contrary, are incliried to deposit crystalline matter on being cooled, and do not possess the salve-like nature of the natural product.* An apt comparison is in the different appearance of ice cream made with and without the addition of gelatine and in both cases—vaseline and ice creaam— the presence of a protective colloid may be the explanation. A peculiar illustration of the coagulation of a colloidal solution is seen in the action of flowers of sulphur on the yellow liquid which is produced by treatment of sulphur-containing distillates with sodium plumbite. There is a rapid flocculation and a dark brown precipitate appears. * By this is meant the material which is obtained from a suitable crude oil by distilling off the lighter compounds and decolorising the residue (usually by filtration through fuller’s earth). 97 The United States Navy Department and the Submarine Defense Association have developed a “ colloidal fuel,” and a summary of their report follows :— * Pulverized coal can now be successfully held in suspension so that the colloidal liquid flows freely through the pipes pre-heaters, and burners of ships and power, heating and industrial plants equipped to burn fuel oil. Months after mixing, the composites show little or no deposits. A fixateur, which comprises about 1 per cent. or 20 lbs. per ton, acts to stabilise the particles of pulverised coal dispersed in the oil. In colloidal fuel every solid particle has its film of liquid hydro- carbon and a protective and peptizing colloid, itself combustible. These particles are in three classes as to dimensions—coarse, colloid, and molecular. By coarse is meant here the fineness of fifty million particles per cubic inch. The fixateur and fixated oil are readily made and may be shipped anywhere. The manufacture or distribution of the new fuels incorporating solid carbon in fixated oils involves no doubtful process or industrial problem. On burning, the combustion is so complete that with fair coal there is left no slag and very little ash, what there is being light as pumice and granular as sand. “Tt is the property of colloidal fuel that without loss of efficiency per unit volume or change of oil storage or burning equipment it makes possible the conservation of at least 25 per cent. of the fuel oil now burned, or conversely with the oils now available in increases by 50 per cent. the world supply of fuel that is liquid. We may go further and state that a number of new fuels have been realised, each with varying percentages of oil and solid carbon. One useful composite, in the range of ordinary temperatures, is composed of about half coal and half oi!. Another unctuous semi-liquid is nearly three-fourths coal and one-fourth oil. All the fuel pastes are mobile to sustained and easily applied pressure, and may thus be pumped, fed, and atomised in the combustion ehamber. These semi-fluid composites will constitute the most compact and safest fuel for domestic and industrial use, and they will largely eliminate the smoke and ash nuisances of cities. “For example, industrial colloidal fuel, grade No. 10, devised to use up some poor coal holding 25-5 per cent. ash, is composed of 614 per cent. of pressure still oil, wax tailings, petroleum pitch and fixateur running 18,505 B.T.U. per lb. and 38} per cent. of ‘anthracite rice’ running 10,900 B.T.U. per lb. This grade contains 162,500 B.T.U. per gallon, and has 10-2 per cent. of ash. The fixated oil itself had 151 5750 B.T.U. per gallon. In fuel value, therefore, the colloidal fuel of grade No. 10 is worth 74 per cent. more per gallon than the oil from which it is made. “Tf instead of ‘ anthracite rice’ very high in ash, a crude oil coke which is ashless had been employed, the colloidal fuel gallon would have contained 182,154 B.T.U., or roundly, 20 per cent. more than the oil base, and only quarter of 1 per cent. sulphur.” @ 11454 @ 98 According to Wo. Ostwald (‘‘ A Handbook of Colloid Chemistry ” page 103), petroleum oil fractions of high boiling point are to be classed as iso-colloids, i.e., a category in which disperse phase and dispersion means possess the same (or analogous) chemical composition. The ultra-microscopic examination of a number of mineral lubricating oils (Dunstan and Thole, Jour. Inst. Petr. Tech., 1918, 4, 191) has demonstrated that optical heterogenity exists, although, however, the degree of dispersion is exceedingly high. The same behaviour obtains for the fatty oils and it is possible that lubricating power is in some way connected with this iso-colloidal state. Lubricating greases are examples of oil-water emulsions stabilised by soap. Commonly sodium soaps are used for motor greases and the proportions are lubricating oil (sp. gr. *900--910), 80 parts; stearin acid, 15 parts; and caustic soda, 2 parts. Part of the oil is mixed with the stearin acid and this is added to the soda in 40 per cent aqueous solution, with constant agitation. The remainder of the oil is then incorporated. Cheaper greases are compounded with lime soaps. Acheson’s oil-dag and aqua-dag are suspensoids of graphite in oil or water containing a protective colloid (tannin). Aqua-dag is made first, and the graphite is transferred from this to oil. The oil-dag contains about 15 per cent. of “‘ deflocculated graphite ” and is used in a dilute solution of lubricating oil (0-1 per cent. graphite) with beneficial results to the bearings, which gradually become coated with a “ graphitoid ”’ layer. ; The colloidal graphite in oil-dag may be removed for analysis in two ways. Freundlich (Chem. Zeit., 1916, 40, 358) throws out the graphite by adding an electrolyte (acetic acid) to the benzol solution of the oil-dag whilst Holde (Zeit. f. Hlektrochem, 1917, 28, 116) adsorbs the graphite on recently ignited Fuller’s earth in a Gooch crucible. A German proprietary material named ‘“ Kollag ” appears to be similar to oil-dag. The influence of colloidal bituminous matter which is mechanically carried over during distillation is frequently sufficient to preyent the easy separation of paraffin wax from that fraction known as “ heavy oil and paraffin,” and recourse is made to a sulphuric acid treatment before refrigeration. The paraffin scale is usually discoloured and contains a greater or less amount of uncrystallisable material which is removed by the process of “ sweating,” i.e., fractional fusion. This operation serves to raise the melting point of the wax and also in part to purify it. Final decolourisation is effected by filtering the melted wax through Fuller’s earth, bauxite, or prussiate charcoal. THE COLLOIDAL STATE OF MATTER IN ITS RELATION TO THE ASPHALT INDUSTRY. By Currrorp Ricnwarpson, M.Am.Soc. C.E., F.C.S. (Consulting Engineer, New York). The presence of mineral matter in a high state of sub-division in a system solid-liquid, the latter phase consisting of asphalt, reveals some interesting phenomena, connected with the relation of surfaces of solids and films of liquids, particularly where the mineral matter is sufficiently subdivided to exist in a colloidal state as regards the 99 bitumen. Owing to the viscosity of such a continuous phase the particles of mineral matter with which it is associated may be regarded as a colloidal state, although they may be of dimensions which would prevent their existence in such a state with a more mobile liquid, such as water. Clay and finely divided silica present such a relation to a highly viscous liquid, asphalt for instance, which may be regarded as a colloidal one. Attention was attracted to the subject in the course of a study of the native asphalt found in the Pitch Lake in the Island of Trinidad, British West Indies. This deposit is unique from a geophysical standpoint. It exists in a crater of an old mud spring on the West Coast of the island, and at a distance of about half a mile from the Gulf of Paria. Its surface was originally 138 feet above sea level. Borings which have been recently made show that the crude asphalt exists to a depth of more than 175 feet at the centre of the deposit, which consists of a bowl-shaped mass covering, originally, an area of 114 acres. Specimens taken at various points on the surface and at different depths show that it originates in an asphaltic petroleum, derived from oil sands occurring at con- siderable depth below the lake, with which a paste of mineral matter and water, originating in a mud spring, has become associated by the churning action of the natural gas accompanying the petroleum, on the release of the pressure to which it has been subjected as the oil approaches the surface. The material formed in this way is of highly uniform composition in all parts of the deposit, and consists of an emulsion of bitumen with a paste of clay and fine sand, and has the following composition :— Per Cent. Bitumen - - - - - . - - 39 Mineral matter - - - - 27 Water and gas, volatile at 100° Co - 4,29 Water of hydration of mineral matter = - - 5 100 The water, which on melting the asphalt under certain conditions can be separated therefrom, in a somewhat concentrated condition, has been found to contain in solution large amounts of sodium chloride and sulphate with a considerable amount of ammonium and ferrous sulphates, together with borates and a readily recognisable percentage of iodides. It also contains smaller amounts of potassium, calcium, and magnesia salts. It is plainly of thermal origin. Refined Asphalt. As it occurs in the deposit it is known as crude asphalt. As such it is submitted to a process of so-called refining at a temperature of 325° F., which removes the water and results in a material known as refined asphalt, which has the following composition :— Per Cent. Bitumen - - - - - - ef Mineral matter - - - - - 39 Water of hydration of lay - - - - 4 100 100 In determining the percentage of bitumen in the refined material by means of solvents it is found that some of the mineral matter passes through the finest filters and is not removed from the solution on prolonged centrifuging. On examination under the ultra- microscope it is revealed that it consists of clay in a colloidal condition, originating in the mineral matter of the mud spring in which it existed in this state as regards the water with which it is associated, and which is introduced into the bituminous phase on the removal of the water on refining. The amount of mineral matter in the colloidal state depends on the concentration of the solution, that is to say, upon its viscosity, as shown by the following data :-— Characterisation of Solutions of Trinidad Asphalt (T.R.A.). Amd Ae anti : gravity solute ee : Per cent. concentration. Pp, ms ig increase for | Viscosity itis, ae: po = y: 1 per cent. | of Solution. oe re ; (T.R.A.). We eee Solvent : Benzol - 0-876 _ 0: 00652 — 1 per cent. (T.R.A.)- 0-877 0- 0010 0- 00654 0- 00002 2 . he 0-879 0- 0020 0- 00687 0- 00033 5 0 2 0-883 0- 0013 0: 00759 0- 00024 10 “4 a 0-889 0- 0012 0- 00961 0- 00040 20 es a 0-911 0- 0022 0- 01629 0- 00067 30 ” paints 0-930 0-0019 0- 04198 0- 00257 40 ” bys 0-957 0- 0027 0: 09477 0- 00521 50 0 eth 1, 012 0- 0055 0-31800 0- 02240 100 ” Ping 1-400 0- 0076 — — Characterisation of Solutions of Trinidad Asphalt. Refined, amount calculated per 1 per cent. (T.R.A.). ; Refined, per cent. Per cent. Concentration. Gaicidal inte $e Solvent : Benzol— 1 per cent. (T.R.A.) - - - 2:54 2-54 eis a - - - 2-01 1-00 DT 55 5 - - - 2-09 0-42 UO) Gee; Ss - - - 2-73 0; 27 vets a saivibisehe' toe? 3-13 0-16 30s, 2 - - - 4-19 0-14 LO iss “ - - - 6°51 0-16 50s, % - - - 10:69 0-21 100s, ” = - - 35-40 0-35 In dilute solution it appears that the amount of matter in a colloidal state is comparatively small, but with increased concentration, that is to say, with increased viscosity of the continuous phase, it 101 becomes progressively larger until in the refined asphalt itself all of the mineral matter, at ordinary temperatures, may be regarded as in a colloidal state. Trinidad asphalt appears, therefore, to be a material the components of which are in a state of equilibrium. and this accounts for its uniform composition. It is, therefore, a unique material, and it is to the large amount of surface energy developed by the highly divided mineral matter which it contains that the demonstrated industrial value of the asphalt is to be attributed. The Introduction of Colloidal Clay into the purer forms of Bitumen. In the light of the preceding facts the inference was drawn by the writer that clay in a colloidal state might be introduced in a similar manner, industrially, into the purer forms of asphalt, and into the residual asphalts prepared from petroleum. For this purpose, a paste of clay and water, in which the clay was in a colloidal state as regards the water, was emulsified with residual asphalts from various types of petroleum. The water was then driven off at high tempera- tures and it was found that the relation of the clay to the bitumen became a colloidal one. The proportions were so selected that the resulting material, after the removal of the water, should consist of 67 per cent. bitumen and 33 per cent. of clay. These materials were then maintained in a melted condition in tubes for 24 hours, at a temperature of 325° F. The sedimentation which ensued, with the reduction of the viscosity of the continuous phase at this high tempera- ture, varied with the different residuals, and was as follows :— Per cent. Colloida' Matter. Per cent. Source. Penetran: = Sedimenta- vis Te pero Before | After tion. Subsidation. | Subsidation. Trinidad Residual - 50 33:5 33-7 0-0 Bababui = - 48 32-4 30-1 7-0 Mexican 4 : 50 33°3 27-2 18-3 California = : 50 31-8 23-8 25-2 Mid-Continental Semi- 51 33°8 21-7 35-8 Paraffin Residual. It is apparent from the preceding data that the colloidal capacity, if it may be so designated, of the different materials is characteristic of the particular bitumen and of its viscosity at a definite temperature. The various bitumens are, in this way, very plainly differentiated. industrial Application. Industrially these observations are of importance, especially in the construction of asphalt pavements, such as that laid on the Victoria Embankment in London. The mineral aggregate of this surface consists of fine sand, a filler for the voids in the sand, 102 Portland cement, and the mineral matter afforded by that present in the Trinidad lake asphalt cement which forms the cementing or binding material of the surface. Experience has shown that the stability of such a surface under heavy travel is dependent on the amount of surface energy developed by the mineral aggregate, that is to say, by the state of sub-division of the particles composing this aggregate. While this will depend upon the size of the sand particles and of those composing the filler, it is also contributed to by the highly developed surface of the colloidal components of Trinidad asphalt and to an extent which would be entirely lacking if the purer forms of bitumen were used with the aggregate, a fact which has been demonstrated by the difficulties which have been encountered in the construction of asphalt surfaces with the residual pitches, free from colloidal mineral matter, which have been met with in the past decade in England, and which have necessitated the employment of various expedients to overcome them. The relation of surfaces of solids to films of liquids, especially when the surface is developed to such an extent as occurs in material in a colloidal state, has been demonstrated, therefore, to be a matter of supreme importance in carrying out successfully the construction of asphalt roadways to carry intense traffic. [Norr.—A more detailed account of the colloid chemistry of asphalt is given in the following paper: ‘ The Colloidal State of Matter in its Relation to the Asphalt Paving Industry,’ C. Richardson, Minnesota Engineering Society, May, 1917. W. C. McC. L.] VARNISHES, PAINTS AND PIGMENTS. By B. 8. Morrety, M.A.Ph.D., F.LC., Chief Chemist, Mander Bros, Wolverhampton. In spite of the importance of the problems of surface it is surprising that the scientific study of the class of products comprising varnishes, paints and pigments, has been so much neglected. The primary components in some form or other, dissolved in a suitable liquid or a finely ground pigment incorporated with a medium as in a paint, introduce a field of investigation of great practical importance and of absorbing interest. If the medium contains water, as in water paints, the properties of ordinary emulsions are prime factors of success. Problems of viscosity arise in varnishes, paints, dopes, and coatings containing cellulose esters; moreover polymerisation .of drying oils confers valuable properties on many varnishes and paints. The conditions of spreading on a surface depend on the physical properties of the components and of the mixtures. The changes on “drying” are essentially superficial, involving questions of adsorption, oxidation, and polymerisation, causing increases in viscosity. The permeability to water and the alteration in the appearance of films’ introduce the study of the properties of gels. The resins in their many forms are typically colloid bodies, and their solutions show the properties of that class. The thickened oils Ue et Bee 103 are considered by some to belong to the class of Isocolloids (Wo. Ostwald). Drying Oils. The drying oils used in varnishes and in paints in contact with - water ought to behave like other vegetable oils in their power to yield emulsions, and the generalisations laid down in E. Hatschek’s Report (B.A. Reports on Colloid Chemistry, 2, 16), may be considered to apply.’ (See also ‘‘ Modern Conceptions of Emulsions,’ W. Clayton, J.S.CI., 38, 113, 1919.) The drying oils seem to differ among themselves in their emulsifying power, although no drop number data are available. In the writer's opinion soya bean and linseed oils are superior to China wood oil; moreover, polymerised linseed oils emulsify better than raw linseed oil, but the emulsions are less stable. The properties of the emulsions with the soaps of the drying oils containing divalent metals are similar to those of other vegetable oils. When a drying oil is thickened by heat out of contact with the air a marked increase in viscosity and modification of other physical and chemical properties are manifested. (The Chemistry of Linseed Oil, J.N. Friend, 1917, contains a full bibliography of the subject.) Thickened linseed oil contains polymerised molecules, but there is also evidence of the shifting of the unsaturated linkages (Morrell, J.S.C.I., 84, 105, 1915). Such thickened oils are considered by Wo. Ostwald to belong to the Isocolloid class which includes petroleum, paraffin, liquid sulphur above 170° C.,and highly polymerised liquids. (Wo. Ostwald, ‘‘ Handbook of Colloid Chemistry,’ 2nd Edit., p- 102.) The Isocolloids are considered to be composed of one chemical substance; in other words the disperse phase and the: continuous medium contain the same substance in different states. Their internal friction shows remarkably high temperature coefficients varying greatly with changing temperature. Comparison with the system styrol-metastyrol is, perhaps, the best in considering thickened drying oils (Lemoine, Compt. Rend., 125, 530, 1897, and 129, 719, 1899). Seaton and Sawyer (Jour. Ind. Eng. Chem., 8, 490, 1916), in an investigation on the molecular weights of drying oils and their polymers have found that only in stearic acid as solvent were they able to obtain values of the molecular weights which were independent of the concentration of the solution or which showed absence of combination of solvent and solute. ; In view of the complexity of composition of linseed oil with its varying amounts of mixed glycerides more reliable results may be expected from China wood oil. C. J. Schumann (Jour. Ind. Eng. Chem., 8, 5, 1916) has investigated the changes which Tung oil undergoes on heating. The oil at first forms a simple polymeride and on further heating it sets to a stiff gel. Schapringer (Chem. Zent. Blatt, 2, 1469, 1905), considers that. the gelatinisation proceeds in two stages, the first progressive, and the latter instantaneous; a case of mesomorphic polymerisation. (Kron- stein, Ber. 35, 4150, 1902, and 49, 722, 1916.) 9 104 Fahrion considers that the polymerisation of wood oil is not analogous to that of styrol. Polymerised styrol, on further heating, yields styrol, but not so in the case of wood oil (Farb. Zeit., 17, 25, 83, 1912, and Ber., 49, 11, 94, 1916). Schumann concludes that a dipolymerised glyceride is first formed which has the power of forming molecular complexes under favourable conditions, giving an insoluble colloidal mass, not, however, accompanied by any further loss of double linkages beyond those diappearing in the first stage of the change. : The presence of decomposition products from the oil prevents the gelation; rosin has the same effect. The solid gel is stated to be transformable into the dipolymer on heating with rosin or with the decomposition products of the oil. It is stated that if the decomposi- tion products of linseed oil are removed while the oil is heated linseed oil will gel rapidly. Schumann concludes that the polymerisation is mesomorphic. The writer (Morrell, J.S.C.I., 87, 181, 1918) can confirm the formation of the dipolymer with its subsequent gelation, but he wishes to lay stress on intramolecular changes occurring during the heating of other drying oils; thus Cyclolin or Polyolin (solid polymerised linseed oil) is difficult to saponify, insoluble in amyl alcohol and is considered by de Waele to be of a ring structure (Jour. Ind. Eng. Chem., 19, 1, 1917). Krumbhaar states that the speed of polymerisation of Tung oil constitutes the greatest difference between it and linseed oil, and agrees with Fahrion that the polymerisation product is partially soluble in the unchanged oil. The viscosity increases with the amount of the polymer until saturation is reached, when the polymer is thrown out. (Chem. Zeit., 40, 937, 1916.) This property of thickening is only markedly shown by the more highly unsaturated oils of the open chain series. Union of molecule with molecule undoubtedly occurs and the polymeride remains dissolved in the liquid oil with increasing viscosity until the fluid coagulates. In the writer’s experience half the oil has been poly- merised short of the point of setting, beyond that point the mass consists of a gel of the dipolymeride whose viscosity is influenced by the presence of specific substances as in the case of gelatine in water. The problems of polymerisation and of thickening of drying oils are of the highest practical importance. Further investigation of the Polyolin of China wood oil would throw light on the properties of the thickened oils, especially in their emulsions in water and in other media. The formation and properties of linoxyn, the oxidation product of linseed oil, are those of a gel, due to oxidation and not to heat, as in the polyolins or cyclolins (Annual Reports of the Society of Chemical Industry, 1916-18). In the manufacture of lmoleum (A. de Waele, Jour. Ind. and Eng. Chem., 9,1, 1917,and M. W. Jones, J.S.C.I., 1919, 88, 26) four oxidation products result of which linoxyn is one. These differ in degree of oxidation and linoxyn may be considered as solid oxidised linseed oil. It must again be noted that the degree of unsaturation plays an important part, because olein gives no linoxyn 105 substance, although it contains unsaturated groupings. In oil varnishes the function of linoxyn is of paramount importance. J.N. Friend (Chem. Soc. Trans, 111, 162, 1917) +has, studied the effects of heat and of oxidation on linseed oil with reference to changes of density, viscosity, and coefficient of expansion. The problem is complicated by the decomposition of peroxides with the loss of water carbon dioxide, and organic vapours. There is an increase in volume up to the setting point of the oil, after which contraction ensues, and the expansion is dependent on the increase in weight. The contrac- tion suffered by the linoxyn explains the cracking of old paint. The action of driers is bound up with the formation of peroxides. (Ingle, J.S.0.I., 36, 319, 1917, and Morrell, Chem. Soc. Trans., 118, 111, 1918.) From the writer’s experience the peroxides undergo polymerisation passing from viscid oils to varnish films. On exposure to air the peroxides undergo slow decomposition. (Ingle, J.S.C.J., 1913, 32, and 38, 101, 1919, and Salway, Chem. Soc. Trans., 109, 138, 1916.) The gelatinisation of drying oils and oxidation is a problem of the greatest importance affecting the protective power of coatings on wood and on metal. No doubt too much attention has been paid to the interpretation by changes due to modifications in composition or in orientation, but the distinctive and finer differences in the qualities of the coatings often find no explanation on strictly chemical grounds, and the investigator is driven to find some other cause. Many observers have noted the importance of the presence of the glyceryl radicle in the drying of an oil film although its presence has no marked effect on rate or amount of oxygen absorbed. Primarily surface phenomena have to be studied and as yet no adequate help has been. rendered by experience of other colloid systems. The writer has experienced this difficulty for many years, and is of the opinion that much can be learnt by closer investigation on the lines of study of the properties of gels. (Morrell, J.S.C.L., 1920, 89, 153.) et In the changes occurring during the drying of oils attention must be paid to the surface action of the drier. Driers like lead and manganese are in colloid solution, and according to Wenzel’s Law the amount of chemical change in unit time is proportional to the absolute surface. If it be granted that there is a large absolute surface in colloids many reactions will occur more rapidly and the phenomena of catalysis are especially marked in colloid systems. Ostwald (‘‘ General Colloid Chemistry,” p. 95) states that surface tension may be either raised or lowered by chemical action occurring in the two phases. A lowering of the surface tension between two phases would accelerate the reaction. To the best of the writer’s knowledge no such measurements in reference to linseed oil have been published. From his own experi- ence from the measurement of the weights of drops in air by Morgan’s method (Amer. Chem. Journ., 38, 1911), no change in surface tension of China wood oil before and after exposure could be observed. Possibly the linoxyn was insoluble because it 106 was necessary to filter the oil from an insoluble skin before the weight . of the drops of the exposed oil could be determined. The surface tension of lead drying oil against air is, however, lower than that of linseed oil, from which it would follow that the lead soap would tend to accumulate on the surface, whereby its specific surface would be increased and consequently its chemical activity. The whole subject requires further investigation, and it is much to be deplored that so little attention has been paid to it. Varnishes. In a paper on the viscosity of varnishes, Seaton, Probeck, and Sawyer (Jour. Ind. Eng. Chem., 9, 35, 1917) state that varnishes show two types of solutions, viz., true and colloidal; they may, under certain conditions, show the Tyndall effect. The suspensoid and emulsoid classes differ in viscosity character- istics. The systems consist generally of three components, resin, oil, and thinner, 7.e., resin incorporated by heat with oil and thinner added. The variation in the viscosity of the emulsoid type with change in concentration is very great. Seaton shows that the viscosity temperature curves (determined by the Doolittle method) of the true solution type, containing soluble gum and low in polymerised oil, are curves whilst varnishes containing highly polymerised oils give straight lines; moreover, determinations of the viscosity of — varnishes at various temperatures will give information as to the ~ nature of the varnish solution. Decrease in dispersion increases viscosity in emulsoid colloids and addition of thinner, increasing the dispersion of the polymerised components, will lower it. If Seaton’s view is correct the viscosity temperature curve before addition of the solvent would be a straight line, but after addition of the thinner it would be a curve. The examples given by Seaton are striking, but a number of variables define the viscosity of emulsoid colloids besides concentration, temperature, and degree of dispersity (Wo. Ostwald, J'rans. Faraday Soc., 1913, 9, 34); especially there is to be considered solvate formation where the viscosity increases with the amount of dispersion medium taken up by the disperse phase. In view of the difficulty in deciding with accuracy the amount and even presence of polymerised oils in varnishes such a relationship as indicated by Seaton is of great value. Similar changes in viscosity during ageing are of importance because unless. the viscosity approaches a constant value in a month’s time the varnish may become unsuitable. The importance of viscosity measurement in the standardisation of aeroplane dope and aircraft varnishes has been fully recognised as a determining factor for flow and freedom of working of these — coatings. In view of the variety of composition of varnishes the — volatility of the thinner as affecting the flow is of considerable practical importance. } Varnishes often contain a disperse phase associated with the — continuous medium. ¢ f 107 The application of Hatschek’s formula :— ” = viscosity of the continuous phase. 7! = viscosity of the emulsion phase. A = ration of total volume of the emulsoid to the volume of the continuous phase. * (Zeit. Chem. Ind. Kolloid, 11, 284, 1912) would throw light on the relationship of resin, oil and thinner and also on the composition of the disperse phase, although the formula is stated to be inapplicable to organic solvents. Von Smoluchowski (Koll. Zeitsch., 18, 1910, 1916) does not consider the prospect of deducing such a formula likely to be suecessful. The drying of varnish films is chemically an oxidation process accompanied by increase in weight, volume, and in viscosity during the formation of the colloid lmoxyn. The rate of drying may at first be rapid, followed by a period of sweating or syneresis. After a time the sweating disappears; this is possibly a chemical process connected with movements in the combined oxygen of the peroxides primarily formed or to changes in the character of the preliminary linoxyn coating. Wolff (Farben Zeit, 24, 1119, 1919) maintains that oxidation and polymerisation proceed at rates depending on the wave length of light to which a varnish is exposed. ~ It is to the linoxyn that the water-resisting power of varnishes is due. Recently work has been done in connection with the protection of metal and wood parts of aircraft under the auspices of the British Engineering Standards Association, and for the Materials Section of the Technical Department of the Air Ministry. Few resin or resin oil coatings are impervious to water; possibly Japan lacquer is the best. From the writer’s unpublished investigations the whiteness of a varnish layer when immersed in water is an emulsion of water in the resin oil mixing as continuous medium. An emulsion would be formed if the emulsifying agent in this case, the resin or oil soap, forms a colloid solution in the non-aqueous solvent (Bancroft, Jour. Phys. Chem., 17, 501, 1918). The best water-resisting coatings give an emulsion with difficulty, and although the layer may take up as much as 5 per cent. water, the varnish film will remain clear. The conditions are essentially dependent on the nature and concentration of the linoxyn surface layer and on the nature of the oil and rosin together with the electric charge on the metallic components present in the mixing. It must be pointed out that increased rate of drying of the oil is not sufficient to prevent emulsification. The surface layer of a varnish. is essentially semi-permeable to water, but not to salts contained therein, e.g., NaCl, K,SO,, KCNS. If plain wood be suitably varnished and placed in water absorption will proceed at a rate which varies with the nature of the coating. Professor Lang and the writer have found that for a high class article 108 the daily rate is 0-0003 grms. per sq. cm., and the rate appears to be the same either in a water-saturated atmosphere or when immersed in water. The absorption will continue without whiteness appearing until the wood is impregnated and the emulsion can form. Similarly, gelatine under shellac will pull water through the film. If the film is in glass, cloudiness will appear at once in the absence of the absorbing undercoat, or if the layer is applied on an impervious surface. The milkiness disappears generally on drying the film. On continued immersion swelling ensues with the formation of blisters and detachment of the film. Often the surface is ridged and shows numerous perforations as if the surface had been scratched and punctured, so that the water absorption on a glass plate becomes steady owing to complete saturation. The swelling must be due to the osmotic pressure of the colloid solution under the protecting layer of linoxyn compelling the compensating migration of water which forms the disperse phase of the emulsion. It has been shown that normal solutions of NaCl, MgCl, and CaC,l prevent the whiteness of an ordinary varnish film and reduce largely but do not prevent the passage of water through the film. N/2 solutions of the above salts have nearly the same effect, and this is true for solutions of K,SO, and KCNS. There are slight differences in behaviour due to the nature of the metal, so that although sodium and potassium salts show the same behaviour yet magnesium is slightly different to calcium, and that again different to aluminium in the form of chlorides in normal and half normal solutions. In the case of calcium there is an indication of surface adsorption with the production of a surface bloom which can be rubbed off leaving a clear film. From the figures given by the Earl of Berkeley and Hartley (Roy. Soc. Proc. A, 92, 477, 1916), it would appear that an osmotic pressure approaching 13-5 atmospheres is necessary to prevent the passage of water into a high-class ordinary outside varnish. With the solutions of N/20 and N/200 of the above salts the water absorption increases largely, and attains its maximum in distilled water. The concentration of the linoxyn surface film together with polymerisation of the drying oil present appear to be factors deciding the impermeability ; whereas the formation of the emulsion with the absorbed water depends on the nature of the emulsifying pent in the oil. (Morrell, Jour. Oil and Col. Chemists’ Assoc., 111, 36, 1920.) Sufficient has been given to show that in varnish films similar problems await solution as in ordinary emulsions, and the experience gained in researches on colloids in a water medium are of great value although the presence of non-aqueous solvents render many of the generalisations inapplicable. Reference may be made here to some instances of application of knowledge gained by investigation of other colloid systems. Bancroft (Jour. Phys. Chem., 19, 275, 1915) gives a number of instances of emulsions involving the use of varnish materials, e.g., bronzing liquids in which the metal goes into the dineric surface. Gelatine can be precipitated from a solution of glue by shaking with benzole, and rosin dissolved in dilute caustic alkali can beremoved _ * , 4 4 109 by benzene (Winkleblech, Z. Angew. Chem., 19, 1953, 1906). Kerosene - benzol, carbon disulphide, chloroform act similarly, but ether has no effect, and produces no emulsions. Such emulsions are noticeable - in varnish analysis and are considered by Bancroft to be due to violent shaking, causing drops of the second liquid, which have the power of condensing colloid particles on the surface and coalescing to larger complexes, to form a rigid emulsion with water. Colophony in the form of resinates behaves similarly to the soaps _ of fatty acids in forming emulsions. Among the more recent contri- butions to the subject may be mentioned the work of L. Paul (Kolloid Zeits, 21, 176-91, 1917), who states that solutions of alkali and resin _ soaps behave like highly dispersed colloid systems. These colloidal _ soaps combine with basic dyes to form coloured rosin lakes and are = - characterised by the readiness with which they combine with petroleum hydrocarbons (Z. angew. Chemie., 28, Ref. 41a 73875 lols and Seifen Zeitwng., 42, 640, 659, 1915). The same author (Kolloid Zeits., 21, 148 and 191) finds that certain fractions of the distillate obtained by distilling a mixture of colophony with phenol or a and B napthol yield dyes with diazo and tetrazo-compounds. Just as in the case of fats, fatty acids, soaps, and tannic acid, the surface tension of water is lowered by resins or resinates which may be considered to assume emulsoid or suspensoid properties in different dispersion media. J. Friedlander (Z. phys. Chem., 88, 430, 1901) - showed in the solution of rosin in 1 perjcent. alcohol how very slight are the changes in viscosity of a liquid when it takes up a suspensoid phase, and again a solution of rosin in alcohol containing a little water possesses a relatively high temperature coefficient (5-6 per cent. per degree temperature) against that of water, 2 per cent. (Hardy, Z. phys. Chem., 38, 328, 1900). Cohn (Chem. Zeit, 40, 791, 1916) describes gel formation produced when colophony is treated with aqueous ammonia. A. P. Laurie and Clerk Ranken (Roy. Soc. Proc. A, 94, 53, 1917) describe the imbibition exhibited by some shellac derivatives. The solid which separates on cooling a solution of shellac in boiling sodium carbonate when immersed in water expands rapidly and ultimately disintegrates to a flocculent precipitate. At the maximum point of expansion the solid on immersion in a solution of sodium carbonate contracts, expanding again when transferred to water. It was found _ that the expansion was inversely proportional to the concentration of the salt solution. Since the shellac molecule is here considered to be permeable to salt solutions the mechanism of the expansion may be accounted for by the passage of the salt solution through the diaphragm, the soluble nucleus dissolving in the presence of the salt solution and the amount which can dissolve controlling the consequent osmotic pressure. Shellac films from spirit solutions do not absorb normal salts from half normal solutions. The writer (loc. cit.) has found that the presence _ of salts, e.g., N/2 K,SO, or N/2 KCNS reduces the water absorption of the shellac film and no salt could be detected passing through it. _ The water absorption by shellac is much less than in the case of ordinary varnishes, but the effect is more permanent giving a cloudy 110 layer which does not clear on drying and becomes very granular with eventual loss of cohesion. Like varnish films shellac gives a semipermeable membrane and with half normal solutions of salts the absorption of water is practically inhibited. _ In a varnish film such an equilibrium would leave the film clear, but in shellac there is a persistent cloudiness indicating that the film is becoming granular. The examination of the properties of shellac films is of interest in comparison with oil rosin films. In some respects there is much in common, but in the impregnated shellac film, water is probably the continuous medium. As in the case of oil varnishes a certain per cent. of water can be absorbed without opalescence appearing. Natanson (Z. phys. Chem., 38, 690, 1901) has followed up Poissan’s researches of 1829 in which it was stated that when a liquid is subjected to deformation a certain time is necessary for obtaining equilibrium, different for different liquids. Liquids have a very small relaxation value. For castor oil from G. de Metz’s results the relaxation time is 0-0031 secs., and for solutions of tragacanth and collodion, values of the same order. Reiger (Physik Zeitschrift, 8, 537, 1907; and Annalen der Physik, 4, 31, 51, 1910) has shown that fluid mixtures of rosin and turpentine have a possible elastic reaction by an oscillatory viscometric method provided due allowance be made for surface forces. De Metz (Comptes Rendus, 186, 604, 1903) has examined the very slow relaxation in the double refraction of a copal varnish induced by mechanical deformation caused by pressure or extension. The phenomenon of relaxation in a varnish lasts long enough to be observed 1 in the fall in the double refraction. T= pia tc log A — log at to base e and »=nT (Maxwell, Phil. Mag., 4, 25, 129, 1868). T = time of relaxation, A and A! the difference of path of two rays at times t and t4; » = coefficient of internal friction of the varnish and n = modulus of rigidity. The modulus of rigidity of a liquid varnish calculated on the ss at 22° C., and is of the same order as f e that of gelatine in water calculated by another method (c.f. Schwedoff, Jour. d. phys., 8, 341, 1889, and 9, 34, 1890). , where log is above formula is n = 0:12 Paints and Pigments. In the literature on oil paints the. application of the principles of colloid chemistry is very scanty. _ H. A. Gardner (Jour. Ind. Eng. Chem., 8, 794, 1916) discussing the physical character of pigments and paints, points out that the opacity of pigments generally increases with fineness of division. As the refractive index of the vehicle approaches that of the pigment the opacity diminishes. Hence, in turpentine and in linseed oil © the opacity will be less than in water as those media haye higher — refractive indices, 111 A lead paint will be opaque since its refractive index is greater than that of the oil, whilst a silica paint in turpentine or linseed oil will be practically transparent owing to close equality in the refractive indices of pigment and medium. The opacity varies inversely with the amount of oil absorbed by the pigment, but the durability is improved by the presence of more oil. The refractive indices of silica, barytes, zinc oxide, white lead, and zine sulphide are 1-55, 1-6, 1-9, 2-0, and 2-37 respectively. In lithopone a mixture of the components fails to give the same opacity as when prepared in contact. Between the limits of 28 per cent. and 38 per cent. zinc sulphide the covering power is best. It is probable that surface adsorption of the zine sulphide by the barium sulphate occurs. Rapidity of precipitation, strength of solution and temperature control, are factors which aid in the production of fine grained particles giving the greatest opacity. The phenomenon of surface adsorption shown by certain lake bases in the presence of colouring matters is of interest and explains why the highly colloid pigments are often preferred. A measure of the degree of dispersion might be based on their colour. Bingham and Green (Am. Soc. Testing Materials, 1919) distinguish between the viscosity of true liquids and the rigidity of plastic solids. The application of the generalisations drawn from the study of other classes of colloid bodies to problems of the paint industry are referred to by Bancroft (‘‘ Theory of Emulsification,” V., Jour. Phy. Chem., 17, 501, 1913). The use of sodium silicate to give an emulsion with linseed oil to prevent the paint from setting or hardening in the package has been known from 1865. Generally 2 per cent. water is the limit, although 4 per cent. may be employed to prevent settling, provided the emulsification of oil with water is assured. Instead of water as combining medium a rosin oil mixing may be employed. An alkaline water fluid is not desirable, and the addition of zine oxide be the lead white is useful in maintaining the suspension in the linseed oil. KE. E, Ware and Christman (Jour. Ind. Eng. Chem., 8, 879, 1916) recommend that a non-aqueous protective colloid, eg., aluminium palmitate or oleate should be added to mixed paints to which small quantities of water have been added containing a protective colloid to prevent settling of the pigment. The same authors have investigated the skinning, puttying, and livering of mixed paints. Livering is dependent on the acidity of the pigment, and in the case of enamels must be connected with the gelatinisation of the colloid resin due to reduction of its acidity, The coagulation depends on many factors of composition and the presence of foreigi substances. Such gels would absorb oil and thinner with separation of the pigment. Skinning would seem to be caused by the oi! acids acting on the pigment. In an oil paint containing rosin the formation of resinates increases the viscosity and the further formation of zinc soap separating from the viscous solution of zinc resinates gives a gel occluding pr adsorbing 112 the remaining oil (livering). Under suspensoid pigments the adhesive properties and cementing values of paint pigments apparently increase with approach to colloidal form. All paint pigments have colloidal properties. Gardner found in the clear oil upon the surface of specially prepared pigments which had stood for a year, the presence of pigment material showing Browman movement on thinning with benzols. Experiments made with zine oxide and with silica ground in linseed oil (thickened) gave even after thinning with four vols of benzole a cloudy fluid which yielded no clarification on centrifuging, but could be partially clarified by mixing the two fluids, a change probably due to electric neutralisation. Paranitraniline red in oil is clear and slightly coloured, becoming bright red when benzole is added, a colour change common in the case of many suspensoid sols. Prussian blue shows strongly Brownian movement and many particles of chrome green suspensoids are coloured crimson, orange, green, and blue in the ultramicroscope. Carbon black (containing 90 per cent. carbon) probably adsorbs linseed oil as in the case of pigments. In the presence of strongly oxidised or boiled oils precipitation may occur on addition of benzene, which may be due to imbibition of the spirit comparable with the swelling of rubber in benzene or of gelatine with water. Again, if zine oxide or lithopone be ground in alcohol and linseed oil added, the alcohol is displaced probably due to lowering of surface tension by introduction of the®oil. [An excellent summary of the properties and uses of carbon black is given by Perrott and Thiessen (J. Ind. Eng. Chem. 12, 324, 1920,).] Ayres (J.S.C.I., 35, 676, 1916) considers that “‘foots’’ from raw linseed oil can be removed easily by heating to 100° ©. and centrifuging. The presence of the mucilaginous material containing salts is considered by some to be highly detrimental not only in the manu- facture but in the durability of many mixings and paint coatings. Ware and Christman (loc. cit.) conclude that the use of emulsifying agents in paint grinding to prevent hard setting has not been satis- factorily explained. The emulsifying agent must exert no saponifying action on the oil, but the presence of metallic soaps in certain quantity retards the settling. Hurst and Heaton state that the emulsification of the oil requires to be assisted by metallic salts such as zinc sulphate, manganese sulphate, and borax, &c.; moreover the addition of a minute proportion of tannic acid incorporated with the pigment prior to grinding with the oil causes the deflocculation of the pigment (Acheson, J.S.C.I., 80, 1426, 1911). Cellulose varnishes have already been dealt with in previous reports under nitrocellulose, celluloid, and cellulose acetate. A class of varnishes containing synthetic rosins on a phenolic trioxymethylene basis is of growing importance. [Annual Reports of the Society of Chemical Industry (Paints, Pigments, Varnishes, and Resins, 1916, 17, and 18) and G. Matsumato, Jour. Chem.WUnd., Tokyo, 18, 484, 1915; J.S.0.0., 1104, 1915.] 113 The synthetic rosins may be soluble or insolubie in alcohol depending on the conditions of manufacture and show a great variety of chemical and physical properties. Their composition is complex (Lebach, J.S.C.1., 82, 559, 1913). The preliminary substance is a phenol alcohol, C,H, (OH) CHOH. Bakelite discovered by Baekeland, consists of soluble and insoluble forms. On stoving alcohol-soluble Bakelite at 140°-170° it passes to a hard insoluble layer or lacquer or to a solid of high chemical and mechanical resistance (Bakelite C, Resite). Resite has been considered to be. derived from polymerisation products of CH, : <~ > = O (Wohl, Ber., 45, 2046, 1912). The advantages of further study of such synthetic organic colloids seem to invite inquiry. Viscosity, gelation, relaxation effects, and dielectric properties are of importance, and, with the exception of the latter, await investigation. There remains one important class of varnishes, viz., the black japans and black varnishes with carbon black as base. In general, the pitch base blacks ought to show similar behaviour to the resin mixings or to resin mixings containing no oil with allowance for the nature of the pitch (asphaltum or resin or stearine). The knowledge of their properties is in the hands of the craftsmen and owing to the complexity of the mixings is of the nature of a trade secret. Those on a carbon black base involve the knowledge of the properties of carbon black in non-aqueous media. The suspensoid black in a high degree of fineness adsorbing the continuous medium is assisted by an emulsifying colloid forming a membrane around the particle of black. The results obtained from attempts to produce liquid fuel from petroleum and coal dust are industrially applicable in this case, but the presence of resin and oil gives a more favourable medium for holding the carbon black in suspension. _ From the brief summary of a very scanty literature it will be evident that although the main properties are conditioned by the chemical composition of the components, nevertheless the properties which decide between a high and low class of article or between suitability or unfitness are rather to be looked for in a comparison of relationship of phases and in changes of surface energy and adsorption. ; The author desires to express his thanks to Mr. P. J. Fay, M.A. for help in the selection and arrangement of the material for this report. CLAYS AND CLAY PRODUCTS. By A. B. SEARLE, Consulting Chemist, Sheffield. The details of the structure 6f clays and clay products are to-a large extent unknown. This is due to the variety of the materials commonly known as clays, to the complexity of the reactions which take place when the clays are moistened, dried, and heated, and to the extreme difficulty in studying the products of the reactions. @ 11454 H 114 There are numerous definitions of the term clay, but most of them are incomplete. Some are so inclusive as to be applicable to any plastic material, others involve an erroneous assumption as to the manner in which the “ alumina’”’ and “ silica”’ are combined, and no definition has yet been published which is entirely satisfactory. Until a better one is forthcoming the following is convenient, though hy no means free from objection :— A clay is a naturally occurring earthy material, whose chief physica characteristic is its plasticity, and whose essential constituents are reported in an analysis of the substance to be “‘ alumina,” “‘ silica’’ and ‘‘ water.” This definition does not exclude those highly siliceous and plastic materials commonly known as “ brick clays”’ though some of these are known to contain as much as 60 per cent. of materials of a non- plastic, sandy nature, which is certainly not of the nature of elay. When a commercial sample of clay is mixed with an equal weight of water and allowed to stand for a few moments, and the liquid decanted through a sieve having 200 holes per linear inch, this treat- ment being repeated with fresh water until all the small particles have been removed, the residue will usually be devoid of plasticity and will not possess the properties of clay. Usually, it will resemble sand or a mixture of gravel, sand, and rock flour. When some clayey materials, such as some indurated clays, are subjected to this treat- ment, the whole of the plastic material is not removed, but on prolonged exposure to water, or better still, if the water is made slightly alkaline and boiled in contact with the clay for several hours, the material will be effectively separated into a coarser, sandy, non-plastic matter, along with the smallest non-plastic particles. By asuitable modification of the treatment just mentioned, a “ clay ” may be divided into a number of fractions, of which all those consisting of particles which will not pass through a No. 200 sieve are obviously not clay. The finer particles are sometimes designated ‘clay substance,’ but, though they contain the whole of the plastic material, they are not wholly “clay,” as by careful elutriation or repeated sedimentation a further series of non-plastic and siliceous materials may be separated. Seger! suggested that the particles which were carried away by a stream of water flowing at the rate of 0-18 mm. per second should be regarded as “ clay substance,” but this fraction contains a considerable proportion of non-clayey material unless it is derived from a particularly pure clay, so that this use of the term “ clay substance ”’ should be abandoned. The smallest particles which are obtained by elutriating the | materials commonly known as clays are found to correspond more or less closely, on analysis, to a composition which may be represented by the formula H,Al,Si,0,. In some samples of Cornish clay and some kaolins, the composition is remarkably constant, but many highly plastic clays and most fireclays yield a product richer in silica and deficient in the elements of water. The constancy of the composition of the better qualities of white-burning clays has led to the supposition that there is in all clays an essential substance— true clay, clayite, or pelinite—on which all clayey mixtures depend for their chief properties. The existence of this “true clay” has i 115 been so often assumed that there is a widespread impression that it really exists as a definite chemical compound, though it has never been satisfactorily isolated. A further objection to this belief in the existence of a single substance as the essential ingredient of all clays, is the fact that the composition and properties—especially the plasticity—of the elutriated product differs with the origin and nature of the “ clay ” from which it is obtained. A further objection is that all attempts to obtain a pure product by chemical means or to produce a synthetic clay have failed. It has also been suggested by W. and D. Asch? that the essential ingredient of all clays is not to be expressed by a single substance, but by a large number of substances, each of which have a general similarity in composition, but differing from each other in the arrangement of the atoms in highly complex molecules. Thus, all clays possess properties corresponding to those of a series of insoluble acids and may, therefore, be regarded as alumino-silicic acids. W. and D. Asch? go still further and suggest that the essential substances in all clays are alumino-silicic acids, the atoms of which are arranged to form several ring-compounds united together, each ring containing six atoms of either silicon or aluminum together with the requisite number of oxygen and hydrogen atoms (the latter being in the form of hydroxyl groups) to form a saturated compound. In most cases, two or more hydrogen atoms are assumed to be replaced by those of sodium, potassium, calcium, magnesium, or iron. Asch’s theory has been worked out in great detail with regard to the available evidence, but for ‘its ultimate proof it requires the synthetic production of clays of various compositions and_ this synthetical proof has not yet been accomplished. The synthesis of silica in the form of a hexagonal ring compound, $i,0,., by G. Martin® in 1913 lends some support to the suggested constitution of the purer clays. It has also been suggested that plastic clays are compounds of “alumina” and “ silica” with organic groups. This theory does not appear to have been very fully investigated. It has the dis- advantage of being largely inapplicable to the purer kaolins which are almost devoid of organic matter. It was, at one time, thought that the plasticity of clays is due to the presence of bacteria and bacterial products, but this has not been proved, and appears to be improbable. Although there is a considerable amount of evidence of the existence of one or more definite chemical compounds which are the essential ingredients of clays and, therefore, to be regarded as “true clay,” there are numerous properties of clays which cannot be explained by any purely “‘ chemical” theory, and of these the most important is the plasticity. There are also properties which are capable of other explanations, particularly those based on the colloidal nature of clays. The existence of colloidal matter in clays was first established by Th. Schloesing* in 1872, but the most systematic exposition on the colloidal properties of clays is that of P. Rohland® in 1891, and more recently the possession of colloidal properties of clays has been generally recognised’, H 2 116 At the present time, the most probable theories of the constitution of clays are as follows :— (a) Clays are a mixture of adventitious minerals (such as sand) and one or more alumino-silicic acids, the latter being the true clays. (6) Clays are adventitious mixtures of an inorganic colloidal compound, or of several analogous compounds, and of inert minerals such as sand. (c) Clays are mixtures of alumina and silica or other simple mutually precipitated colloids with other non-colloidal minerals, such as sand. A little consideration will show that (a) is not necessarily incom- patible with either (b) or (c), as the two latter do not give any indication of the chemical composition of the colloidal matter. Moreover, (c) is not applicable to all clays, though it may be to some, so that present- day views of the constitution of clays may be reduced to regarding them as mixtures of non-clayey material (sand, &c.), with either (1) a complex compound possessing colloidal properties, or (2) a mixture of colloidal silica and alumina. There is evidence in support of both these theories and no comprehensive combination of both of them has been published, yet neither theory alone explains all the facts, unless it is sufficient to regard the first theory as applying to some clays, whilst the second is more applicable to others. - It appears quite certain that commercially useful clays are not wholly colloidal in character; they rather resemble a mass of mineral particles, each covered with a film of colloidal matter. If the latter could be wholly separated, it would not possess all the properties which make a clay technically useful, and in this respect the application of the term clay to mixtures of sand and colloidal matter would appear to be justified. The laterite clays which are widely distributed in the tropics, are characterised by a large proportion of alumina and silica soluble in hydrochloric acid. The ratio of these two oxides is very variable, and seldom reaches 1 : 2 which is a conspicuous feature of the purer British clays. This great variation makes it more probable that the laterite clays are merely mixtures of colloidal silica and alumina; their other properties resemble those of such a mixture rather than those of typical clays, and the conclusions based on the results of elutriation may require to be received with caution. The proportion of colloidal matter which can be definitely separated from clays is extremely small, being less than 3 per cent.* in the’ most highly plastic specimens.* Many investigators find it difficult to believe that so small a proportion can account for such great differences in the behaviour of lean and highly plastic clays, and have urged this as an argument against the plasticity of clays being due to the colloidal material present. On the other hand, * Ashley’ has proposed to determine the relative amounts of colloids in clays by observing the amount of each required to just decolourise a standard solution of malachite green. This method, whilst useful for comparative purposes, gives no idea of the absolute amount of colloidal matter present. 117 there is a close similarity between the behaviour of many clays and that of a fine concrete composed of Portland cement and fine sand, the freshly-made concrete possessing a considerable amount of plasticity even when the total proportion of colloidal matter present is extremely small. A careful comparison of the structure and properties of such a concrete with those of a plastic clay gives a very clear idea of the possible nature of clay and especially of that of its most characteristic property—plasticity. The properties of clays which are most closely allied to those of colloids or mixtures of colloids and inert materials differ according as the clays are respectively in the dry, pasty, or “slip” state. The pasty condition is produced by reducing the clay to a powder by grinding, and then mixing it mechanically with a suitable proportion of water. Some highly plastic clays‘ occur naturally in the form of a stiff paste which may be softened by crushing between rolls so as to reduce to thin sheets and mixing this mechanically with water. Clay is converted into a slip or slurry by grinding or crushing it and then mixing with a sufficient quantity of water to keep the clay in suspension. The amount of clay which can be suspended in a given volume of water depends on the physical condition of the clay and the presence or absence of very small amounts of alkali, acids, or salts in the water. The following properties of clay can be most satisfactorily eXplained by assuming the presence of colloidal matter :— Water is absorbed by any clay in fairly definite proportions which appear to have some relation to its plasticity, the lean clays absorbing much less water than the more plastic ones. When clay is completely dried without being excessively heated, it is highly hygroscopic and absorbs water readily—sometimes up to 15 per cent. of its weight—without becoming appreciably moist. It is, therefore, difficult to keep clay perfectly dry, and most specimens contain a considerable proportion of water which may, in some cases, cause the clay to be tough and plastic. The hygroscopic nature of clay distinguishes it from silt and sand. When a piece of air-dried clay is placed in water, the latter enters into the pores, drives out the air, and lifts up the smallest particles of clay, disturbing the structure of the material so that a partial or complete breakdown or slaking occurs. The disruptive action of the water on the solid particles forming the clay mass may be attributed to a molecular attraction between the water and the clay whereby the water wets the surface of the latter and the resulting interposed film of water reduces the cohesion of the clay grains so that they separate easily. The absorption of water is accompanied by a slight rise in temperature, which though scarcely noticeable is characteristic. The amount of water absorbed varies greatly with different clays; in some cases, it is equal to 80 per cent. of the weight of the clay. Rohland® suggests that this power of imbibing a definite amount of water is due to the colloids in the clay, and that as soon as the clay has absorbed a sufficient amount of water to convert its colloids into the form of a colloidal sol its ability to absorb water reaches a saturation point and ceases; this is proportional tof[the colloids 118 present, and probably, roughly to the plasticity of the clay. It may, however, be proportional to the capillary spaces between the clay particles. In the manufacture of articles from clay paste, it will be found that each kind of clay requires a definite proportion of water for its efficient manipulation. If more is added it will become too weak, if less it will become too short. This water is known as “ water of formation,” and its amount has a theoretical as well as a practical importance, being closely related to plasticity. Unfortunately, there is no certain method of ascertaining the consistency of the clay paste, nor of ascertaining when the correct proportion of water has been added to a clay. The ordinary method consists in adding such a proportion of water that when the mixture is worked up into a paste it readily receives the impression of finger-prints, but does not adhere to the skin, the amount of water required being found by trial. This procedure is too rough for scientific purposes. If water is added to a moderately plastic, dry clay in increasing quantities, the clay can at first be moulded with difficulty, then more easily, and later it may be moulded with the greatest facility. If the proportion of water is still further increased, the clay becomes sticky, then fluid, and it is eventually impossible to form it into any definite,shape. If the same experiment is repeated with a more plastic clay, using the same proportions of clay and water as before, it will be observed that it will adhere to the fingers and will allow of no further shaping unless its plasticity is diminished by adding non-plastic material or altering the proportions of clay and water. An excessively lean clay, on the contrary, only acquires the desired plasticity when it has a very soft consistency, which does not allow it toremain in any given form, and it must, therefore, be rendered more plastic if it is desired that it should be shaped by hand. If the formation is done by mechanical means, in which the clay is subjected to much stronger pressure, less water must be added to the body in order to give it the required plasticity, and it will be expedient to make it of a stiffer consistency. Pressure, in this case, plays the same part as water in the plastic qualities of clays; the one can be partially replaced by the other, so that if the amount of pressure is increased the proportion of water should be diminished and vice versa. If a sufficient quantity of water is added to a clay to form a slip or slurry, the latter will have certain characteristics, according to the proportion of water and clay, to the nature of the clay and the purity of the water. If the proportion of water is very large and the particles of clay difficult to separate, they may fall to the bottom very soon after the mixing ceases, or the greater part of them may so fall, leaving only the smallest particles suspended in the water for many hours. With high grade clays, such slips have marked colloidal properties (see Viscosity, Adsorption, &c.). Slips containing about an equal weight of water and clay are largely used in various branches of clay-working, for covering other clays of inferior quality when burned, and for making objects by the 119 process of casting. In the former case, the articles to be covered are immersed in the slip, and in the latter, the slip is poured into plaster moulds and allowed to remain for a short time, after which any superfluous slip is poured away. On allowing the mould to dry, the water is absorbed by the plaster, and the clay article may be removed in due course. In both cases, it is necessary that the proportions of clay and water should be carefully adjusted, in order to obtain the best results. When a suitable mixture has been obtained, it will usually be sufficient to weigh exactly one pint of it accurately, and to dilute other mixings with a stronger slip or with water, until they reach the same weight per pint. The specific gravity of the slip may be determined with great exactness in a pycnometer, if desired, but this involves unneces- sary trouble for most purposes. Schwerin has found that water and alkalies in the clay slip may be removed by electro-osmosis by connecting the bottom of the tank containing the slip with the negative pole and the cover with the positive pole of a battery when, on passing a suitable electric current, the water and alkali will collect at the bottom, and the slip will become very stiff and apparently—though not actually—dry. The hygroscopicity of dried clay is very marked, up to 20 per cent. of water being absorbed from a damp atmosphere by some clays. It does not necessarily prove the presence of colloidal gels, but if they were present such hygroscopicity would be anticipated. Miscibility—It is a remarkable fact that highly plastic clays, in addition to having a limited power of absorbing water, are incapable of forming a uniform mixture with less plastic clays. According to Rohland®, this is due to the fact that when colloids in clay are coagulated they form gels which cannot be brought into solution by the addition of more water, and resist the absorption of water. They are also incapable of taking up anything from a second colloid. Hence, if the colloids are coagulated, as in very plastic clays, they will not absorb more than a certain amount of water, will not take up other plastic clays, and will not mix homogeneously with them. Many objectionable qualities of a highly plastic clay may be obviated by saturating it with water and then adding a suitable amount of non- plastic material. In this way, also, highly plastic clays gain the power to be mixed thoroughly with other plastic clays and with felspar, which forms coagulable colloid solutions. Rohland has found that plastic clays in which there is only a small proportion of colloids, and these not coagulated, may be uniformly mixed with other similar clays. Deflocculation —Clays usually exist in large masses which are not readily affected by water, but smaller pieces may be broken down or “ slaked,”’ as just described, in a manner which is very similar to the deflocculation of colloidal gels. If a suitable electrolyte such as sodium hydroxide, carbonate or silicate, or baryta is added, the amount of suspended matter is increased, as with well-known colloids, and, if an acid is added to the suspension, the clay particles are rapidly precipitated like a coagulable gel. Clays are remarkably 120 sensitive to the action of electrolytes, a very small quantity of a solution of soda being capable of converting a clay-paste into a viscous fluid which, on the addition of just sufficient acid to neutralise the alkali, will again become solid. This behaviour bears a remarkably close resemblance to the action of electrolytes on the coagulation and deflocculation of colloids. Rohland® has suggested that the formation of a clay slip (sol) may be explained as due to the action of electrolytes on the colloids present in the “ clay.”’ With a negative sol in colloidal suspension, the most powerful factor in coagulation is the positive ion of the electrolyte added, the negative ion having but little influence. The power of different positive ions appears to be the same for those of the same valency, but divalent and trivalent ions are more powerful than monovalent ones. Thus, Foerster has shown that if a clay contains just enough calcium ions to keep the colloidal matter in the gel state, and sodium carbonate is added, the sodium will combine with the colloid clay so as to form the sol, the plasticity being reduced according to the completeness of the reaction, but if an excess of sodium ions is added they will recoagulate the colloid. This has been confirmed by experiments on the viscosity of clay slips by Mellor and others. The addition of electrolytes to a clay body also affects some of the materials present. Thus, Schurecht® has found that the working properties of mixtures of graphite with sufficient plastic clay to act as a binder, such as are used in the manufacture of plumbago crucibles, are considerably inaproved by the addition of 0-3-0-4 per cent. of sodium hydroxide or, in some cases, of hydrochloric acid, according to the nature of the colloidal matter present. Kosmann® attributes the disintegration action of alkaline solutions on clays to the solution of a siliceous film on the particles which acts as a binder. This explanation scarcely seems to account for the great effect produced by so small a proportion of soda. When clay is saturated with water and an electrolyte is then added, the adhesion of the particles is reduced, partly as a result of the osmotic pressure of the solution on the porous particles!® which then act as a permeable diaphragm and force the water more strongly into the interior of the particles than would be the case if plain water were used. If the basicity or alkalinity of the solution is altered by the addition of an acid, the particles tend to coagulate and adhere to each other with the result that the mass becomes semi-solid. When clay is suspended in a liquid having a higher coefficient of capillarity than water (e.g., acids) the particles tend to precipitate, but in a liquid with a lower coefficient than water (e.g., bases and alkalies), they tend to remain in suspension. This behaviour is attributed to the difference in the adhesion of the fluid particles of the liquid to the particles, the surface of the smallest particles being much greater in proportion to their weight than that of the larger. ones. Adolph Mayer has determined the limiting power of electrolytes which permit a fine clay (freed from carbonates and soluble salts by treatment with hydrochloric acid) still to be kept in suspension in water (100 grammes clay, 500 grammes water). The limits are :— ammonia, 2-5 per cent.; sulphuric, hydrochloric, and nitric acids ae -sS- 121 and the alkali salts of these acids, 0-025 per cent. Although 2-5 per cent. of ammonia caused precipitation in Mayer’s experiments, a less amount favours deflocculation, or breaking up of the lump. The “ fluidity ”’ of any clay slip depends chiefly on the proportion of water added, but it is largely affected by the presence or absence of very small proportions of electrolytes. According to Rohland’, the addition of hydrochloric, nitric, sulphuric, acetic, or propionic acid increases the plasticity of the clay slip, apparently by coagulating the colloidal matter present. Solutions with an acid reaction such as sal-ammoniac, aluminium chloride, ferric chloride, and potassium bichromate behave similarly. Alkalies such as ammonia, caustic soda, caustic potash, lime-water, baryta, and basic salts, make the slip more fluid and reduce the plasticity of the material, but their behaviour depends on their concentration. The action of alkalies in reducing the viscosity, sometimes requires several days, and is accompanied by coagulation. An excess of alkali may cause a reversion of this action, the viscosity increasing again. The addition of salts usually decreases the osmotic pressure and increases the viscosity. Acheson has patented the use of a solution of tannin and alkali to make a clay “ fluid,”’ and, followed by the addition of an acid— presumably by precipitating the colloid matter—to increase the plasticity of the clay. The viscosity of clay suspensions, before and after the addition of various substances, can best be understood by assuming that it varies according to the condition, and proportion of the colloidal matter present. Mellor, Green, and Baugh" have arranged the substances likely to be present in, or added to, clays into five groups according to their action on the viscosity of the clay* :— (1) Substances which first make the slip more fluid, while further additions stiffen the slip. Examples: sodium and potassium carbonates, fusion mixture, potassium sulphate, potassium bisulphate, potassium hydroxide, potassium nitrate, sodium sulphide, tannin and gallic acid. (2) Small amounts thicken the slip; larger amounts make the slip more fluid. Examples: copper sulphate, dilute ammonia, and potassium aluminium sulphate. (3) Substances which make the slip thinner: magnesium, mercury and sodium sulphates, sodium sulphite, sodium acetate, sodium chloride, sodium phosphate, ammonium gallate, hydro- chloric acid, water-glass. It is just possible that some of these substances may have to be transferred to the first (or second group) if greater (or less) concentrations be tried than_ those employed by Mellor, Green, and Baugh. (4) Substances which only stiffen the slip: grape sugar, humic acid, ammonium chloride, calcium chloride, calcium * It should be noted that the slips used were not made trom a single clay, but from a body mixture consisting of 16g. ball clay, 19g. China clay, 13g. Cornish stone, 20g. flint and 100c.c. water, To this mixture, varying quantities of acid, alkali and salt—ranging from 0-1 to 6g. or 0-1 to 35¢.c.—were added. This may account for the difference between these results and those obtained by some Continental investigators, 122 sulphate, ammonium urate, aniline, ethylamine, methylamine. Here, again, some of these substances may have to be transferred to the second (or first) group if greater (or less) amounts than those mentioned are used. (5) Substances which have no appreciable effect on the slip : e.g., alcohol. Rieke has stated that the most soluble substances increase the viscosity of the slip, but their effect may be neutralised by the addition of a solution of barium hydroxide. The most harmful sulphates according to the same investigator are those of calcium, aluminium, and the heavy metals. Alkali sulphates stiffen the slip when only 0-1 per cent. is present; larger proportions render it thinner until 1 per cent. is reached, after which they stiffen it again. Zinc and copper sulphates exhibit this phenomenon of variableness to a marked degree. Bleininger found that the first addition of clay (up to 3 per cent.) decreased the viscosity of water on account of the deflocculation of the clay by dilution and the solution of the contained electrolytes. When, however, the addition of clay became so great that no further matter went into solution and the effect of the gel showed itself, the viscosity increased with each addition of clay. This negative viscosity is peculiarly characteristic of some clays. The size of the particles of the purer clays is comparable with that of colloidal particles, but most clays contain so large a proportion of larger particles that it is almost impossible to isolate those which are colloidal, in an entirely satisfactory manner. The adsorptive power of clays bears a striking similarity to that of colloids, or rather to that of a mass of inert material, the particles of which are covered with a film of colloidal matter which also fills some of the interstices. Thus, clays adsorb soluble dyestuffs, tannin, humus, oil, grease, salts,* &c.; and Hirsch and others have found that barium, lead, and aluminium salts are adsorbed more readily than those of lime and magnesia. Chlorides and nitrates are adsorbed more than sulphates, but alkali salts with the exception of the alkaline carbonates are not adsorbed. The behaviour of the alkaline carbonates may be explained by the almost invariable presence of calcium ions in clays, which react with the carbonate forming a precipitate of calcium carbonate, and so removing the carbonate ion from solution. Rohland® states that some clays which are only moderately plastic may, on the addition of alkali and certain salts, or through some chemical change, be made more adsorptive. The adsorptive power of clay is valuable in some industries, and it is on account of this power that if clay is mixed with neutral or slightly acid muddy solutions or emulsions, when the clay settles it will be found to leave a clear liquid. The adsorption of a clay is usually determined by noting the loss of colour of a dye solution such as malachite green, and comparing it with another similar solution to which a standard clay has been added. * Many clays retain salts so tenaciously that it is impossible to wash them clean with plain water, but they can be removed by washing with a solution of a salt which is more readily absorbed by the clay. 123 If Olschewsky’s suggestion that the particles of clay are porous is correct, the phenomena ascribed to adsorption may really be due to adsorption within the capillaries or pores. The ‘ scum ”’ observable on some bricks is due to the salts adsorbed by the clay and carried to the surface during the drying of the bricks. The capillary phenomena shown by many clays and soils may also be explained on the hypothesis that clays are colloidal in character. The porosity of clays varies with the amount of water present, some stiff plastic pastes being quite impervious, though the same materials are porous when dry. This porosity appears to be associated . with the capillary structure of many clays and whilst it is a property possessed by non-colloidal substances, it is a characteristic property of some colloids. The semi-permeability of clays, like that of colloids, is a characteristic property, and although its nature is by no means well understood, it appears to confirm the presence of colloidal matter in clays. When clays are made into semi-permeable “‘ membranes,” they behave according to their plasticity. The plastic clays effect a perfect separation between the colloid and crystalloid solutions and are truly semi-permeable, but very lean clays such as china clay are very irregular in their action. In some cases, the presence of a crystalloid may cause a sol to pass through a membrane, as when silicic acid is mixed with sodium chloride both will pass through. It is also stated by W. Ostwald" that fresh colloids (particularly silica) will pass through a membrane, but after keeping a few days they will not pass through. * There is no connection between the rate of diffusion through the membrane and the molecular weight. « According to Rohland®, plastic clays will allow ferric chloride and sugar (crystalloids) to diffuse, but not tannin (colloid). In emulsions of oil and water, plastic clays permit the (crystalloid) water to pass, but not the (colloid) oil. In alcoholic solutions of fat, such clays permit the alcohol to pass but not the fat. In aqueous rubber solutions, plastic clays prevent the rubber from diffusing, and in albumen, solutions the albumen is retained, both rubber and albumen being typical colloids. The diffusibility or speed at which the substances dialyse through the membrane depends upon their nature. Thus, water* which is a crystalloid, and electrolytes, e.g., salts dissolved in it, diffuse rapidly, but colloids, such as ferric hydrate, hydrated silica, hydrated alumina, and most products of organic life such as starch, vegetable oils, and gelatin are either indiffusible or pass through with extreme slowness. Colours, on account of their complex composition, play a special part; they are retained by plastic clays, though these colours are crystalloid and not colloid. Berlin blue, potassium ferricyanide, aniline blue, sulphated triphenyl rosaniline, aniline red, carmine, malachite green, fluorescin, aurin, and other animal, vegetable, and tar colours, cannot diffuse through clay, and this, in spite of their crystalloid nature. * Zschokke™ suggests that plasticity is possessed by all substances composed of extremely minute particles with sufficient affinity for each other and with a power for combining with water. 124 The explanation of semi-permeable membranes most widely accepted at the present time is that of selective solubility, suggested by L’Hermite®. The membrane is permeable to those substances which dissolve in it but not to others. _ As the semi-permeability of clays appears to be connected with the plasticity, any treatment which will increase the latter should increase the former. Rohland® has found this to be the case with some lean clays he has examined. Some of the phenomena occur whenever plastic clay is mixed with solutions, as the particles allow the crystalloids in the latter to pass through them, but retain the colloids on their surface. In this way, the adsorption of crystallised matter as well as colloidal matter occurs; but as the particles of clay are so minute the effects are scarcely distinguishable, and clays appear to be capable of absorbing both colloidal and crystalloidal substances. The permeability of raw clays has been studied by Spring, who found that when such clays are confined so that they cannot expand, they will only absorb enough water to fill the .pores. The amount absorbed varies from 3 per cent. with some fireclays to 25 per cent. with some sandy loams. When not confined in this manner, the extent to which the water can permeate a clay is dependent on the amount of non-plastic material it contains, and increases when sand or grog is added. The permeability of a fired clay is an important characteristic, and is described later. The more permeable a clay, the more easily can it be dried and heated without damage, large pores being prefereable to small ones. Wet clay in the form of a stiff-plastic paste is generally considered to be extremely impermeable, but, as already mentioned, this is only ° a relative property, as such a mass of clay, if left in water, will, in time, fall to pieces. Clay which has been suspended in water and allowed to settle is usually quite permeable, as are many natural clay deposits. It is only when the material has been “ worked ” or “ pugged ” that it becomes impermeable. The plasticity! of clays is one of their most important properties. Plasticity may be defined as that property of a material which enables it to change its form without rupture, the new shape being retained when the deformatory force is removed. In other words, a material is said to be plastic when it can be kneaded or pressed into any desired shape, and remains in that shape when the kneading ceases or the pressure is removed; this alteration of shape being capable of being repeated indefinitely. It is a characteristic of many substances besides clays,* though clays possess it to the most marked degree. Ashley? has pointed out that very few people agree exactly with the conception of plasticity. Thus, a brickmaker terms a clay plastic when it works well in his machine, and is capable of being kneaded into a “‘good’”’ paste, but a potter usually places more emphasis on the binding power of the clay, though he terms this its plasticity. Although these definitions are sufficient for practical purposes, they are not entirely satisfactory, nor is there any explanation of the ” * The “‘ possible plasticity ” is that which can be developed under the best known conditions. For many purposes, it is not necessary to develop the plasticity of a clay to the utmost. 125 causes of plasticity which meets all the needs of the case. Plasticity varies with different samples and on different occasions, though no raw moist clays are entirely devoid of plasticity. Clays which are quite dry are not plastic, but become so when mixed with a suitable proportion of water so as to form a paste. Hence, the amount of plasticity developed is dependent on the proportion of water present. Liquids other than water may be added to the clay to produce plasticity, but they must usually contain water, and even then, sometimes produce quite different characteristics. Thus, glycerine may be used, but it prevents the clay from drying, and Krupsay has pointed out that if plastic masses made from clay and glycerine and clay and water respectively be kneaded together the resulting mixture is non-plastic. Fatty liquids, such as oils, seem to make a more plastic body than with water, especially if the clay has been dried so as to take away from it the hygroscopic water, but alcohol, etheg, and turpentine produce bodies with little or no plasticity. The nature of the plastic product formed when liquids other than water are used is worth further study. In the case of an oil, the plastic mass is quite different from that produced with a liquid such as anhydrous nitric acid, anhydrous sulphuric acid, absolute alcohol and glycerine. ach of these fluids is soluble in water, and is, therefore, able to wet the hydrated clay grain with its attached water molecule and to separate the grains sufficiently to produce a plastic mass. In each case, the clay may be “ dried ” again and made plastic with any of the other fluids. According to R. F. MacMichael** only those liquids which “wet” the clay particles can produce plasticity. Water and fatty oils do this, but ether, gasoline, kerosene, engine oil, and ‘similar fluids which do not “wet” the clay grains are either unable to penetrate between them and so do not develop plasticity in the clay or they form a film of such a nature around the clay grain as to prevent cohesion, so that the mass acts like sand and water, but there is no gradation or balancing of the forces, as is necessary in order to obtain true plasticity. Plasticity also depends both on the nature of the fluid and that of the solid. Thus, while both water and oil wet quartz sand, water under suitable conditions will easily displace oil films from a mixture of sand and oil. On the other hand, both oil and water wet zinc oxide, but in this case the oil will readily displace the water films, forming paint or putty. The resulting mass, in this case, may be said to be oleated, in very much the same manner as clay is said to be hydrated. The same principle is employed commercially on a very large scale in the flotation of metal-bearing ores. The possible plasticity? of clay or other substance cannot be developed by commercial methods of grinding unless the material is in a state which may be regarded as dormant plasticity. This has been regarded as an objection to the view that plasticity is due to the colloidal properties of clay, but the objection may be met by the difficulty of reducing some clays to so fine a state as is required to produce the requisite amount of colloidal matter. Plasticity also varies with the presence of certain other substances ; thus, the following soluble substances reduce the plasticity of clay : 126 ammonia, caustic soda, caustic potash, lime, sodium carbonate, potassium carbonate, borax, and water glass. They appear to do this by coagulating the colloidal portion of the clay, but their action may be prevented by the addition of a sufficient quantity of weak acid to neutralise the alkali in the clay. The addition of certain organic acids as humus, or of gum, glue and starch confers a pseudo-plasticity on clay which is, however, quite different from true plasticity and makes the clay “sticky ” rather than plastic. The stickiness of certain clays (e.g., London clay) is very pronounced, but must not be confused with true plasticity. Ashley’ has stated that if the granular constituent is removed from a plastic body it loses plasticity and becomes sticky until the granular constituent is restored. This suggests that the practice of adding granular material of a non- lastic nature, so common among the users of London clay is based upon a sound principle. The stickiness of clay may be regarded as due to colloidal material which is not properly distributed throughout the inert granular mass. Plasticity does not appear to be connected with the chemical composition, as clays which yield the same results on analysis may differ widely in plasticity, yet on heating above 415°-600° C. all clays lose their plasticity, and it cannot be restored. It is also a curious fact that the clays which are richest in “true clay” are seldom so plastic as those which are not so pure, so that any peculiar structure of the clay molecule can scarcely account for its plasticity, though several eminent investigators have laid stress on this suggested cause. Several investigators have attributed the plasticity to the shape or size of the clay particles. Thus, Aron considered plasticity was due to the particles being spherical, but Zschokke, Biedermann, and Herzfeld dispute this, and attribute it to the presence of flat and laminated crystals,* a view early put forward by Johnson and Blake, and held later by Bourry*, who stated that plasticity becomes greater in proportion as the grains diminish, and that all minerals if reduced .to a sufficiently impalpable powder, will on the addition of a liquid produce bodies having a certain amount of plasticity. According to Le ‘Chatelier, the lamellar structure and the well- | known capillary attraction are a sufficient cause of plasticity. He has” shown that all plastic masses contain a large proportion of air by comparing their density with that of clay and water, and that in each plastic mass there are innumerable capillaries of not more than one three-thousandth of an inch in diameter. He concludes that the tension of the menisci between the water-surface and the air-surface in these capillaries explains the toughness of the plastic mass, as the capillary force prevents the mass from breaking up under pressure, but allows the minute particles to slip over each other, and yet adhere so strongly that the mass retains the new form when the pressure is removed. In other words, clay is plastic when sufficient water is * The particles are so extremely minute that it is exceedingly difficult to ascertain their shape. Le Chatelier has noticed that if the material is disturbed when under the microscope, the crystalline form may be observed for a fraction of a second by polarised light if their symmetrical axis is perpendicular to the microscope axis. As soon as they are fiat they are isotropic. q 127 added to induce the cohesion to a point where it can readily be overcome by the pressure of the worker’s hands, i.c., to 1-3 lb. per square inch, so that it is a balancing of forces producing a peculiar combination of fluidity and rigidity in the mass of wet clay; under a light pressure it acts as a rigid body, under a heavier pressure, it acts as an imperfect fluid. The rigidity is attributed to friction between the clay grains, so that a mass of clay retains its form until acted on by a force sufficient to overcome this friction and produce distortion. The fluidity of the wet clay is due to the freedom of the individual particles to move over each other, after cohesion has been partially neutralised by the addition of water. The theory that plasticity, instead of being a special property, is’simply the result of molecular attraction, and that all bodies which are made up of laminated particles must become plastic when they are reduced to sufficiently impalpable powder has been confirmed by Vogt as regards mica, which is highly laminated, being made up of thin layers, and when reduced to an impalpable powder becomes distinctly plastic if water is added. The insistence laid by Bourry* on the laminated structure of the particles has been frequently over- looked, and the suggestion that, because burned clay may be ground equally fine and yet never become plastic his experiments are not conclusive, is irrelevent. Seger!, and independently Schumacher, consider plasticity to be due to molecular differences in the clay particles, and Bischof agrees with the latter in considering that clay has undergone great changes in density during deposition, and a kind of “‘ felting ” of the particles has resulted so that they adhere much more closely to each other than the quartz and other particles in which this felting process has not taken place. Wolff has calculated the attraction of the particles of various substances to each other on the assumption that they are spherical. He finds that the mutual attraction of the clay particles is vety high and that the ratio between their mutual attraction for each other and for water is much higher than for any other substances examined. He stated in confirmation of this theory that other substances can be made plastic, if they can be made sufficiently small, as by precipitation.* He also pointed out that the combined water in a clay particle increases the ratio considerably and is accompanied by an increase in plasticity not only in the clay, but in alumina and iron oxides. Zschokke confirmed this theory, and has shown that clay particles have a thicker film of water around them than particles of non-plastic materials such as sand. It is extremely difficult to find satisfactory reasons for attributing the plasticity solely to the plate-like or lamellar structure of the particles or to purely mechanical or chemical characteristics in the atoms and molecules of the clay and water, though these are undoubtedly important. Nor has the effort of Le Chatelier to find the source of plasticity in the presence of small amounts of impurities proved really helpful. The smallness and shape of the particles appear to be important, as clay ground in a pan-mill is more plastic than when a ball-mill is used, as the former flattens out the material, 128 but this does not really affect the cause of plasticity. Grinding is not a cause of plasticity, though Johnson and Blake claim to have made a non-plastic china clay plastic by fine grinding. It has been suggested by Olschewsky, who based his experiments on those of Daubée, that the water used has a chemical action, and that plasticity is due to the formation of a system of capillaries in the clay, a felt-like or spongy material being formed, and in this way, the clay particles are able to come into closer contact, owing to the production of a kind of gelatinous or colloidal film, but the presence of an alkali appears to be essential for this alteration to take place. Thus, Mellof found ground pottery, felspar, and Cornish stone become plastic on heating with water under pressure to a temperature of 300° C. for several days, but china clay and flint are scarcely affected. The finer a substance is ground the more complete is its reaction with water, because a small particle has a greater surface in proportion to the water than a coarse one. If the particles are sufficiently fine, water may, indeed, act in a similar manner to a caustic alkali; thus, very finely divided silica becomes colloidal when brought into contact with boiling water, just as coarser particles do when brought into contact with a boiling solution of caustic potash. Koerner found that other substances (as alumina) become sufficiently finely divided in water, but their power of cohesion is lost on drying, and suggested that the plasticity may be brought about in a similar manner. This would explain why it is impossible to produce highly plastic clays from kaolin. As many organic substances possess certain characteristics of plasticity, several suggestions have been made that these may be the cause of plasticity in clay. It is found, however, that there is no definite relation between the plasticity and the proportion of carbon in the clay, dark coloured clays, rich in carbonaceous matter, being _ no more plastic than lighter ones almost free from this material. Several observers have suggested that bacteria produce plasticity, but Hecht and Gosmann have not found sufficient data to warrant this suggestion, especially as it has not been found possible to increase the plasticity of clay by inoculation. Whenever plastic clay is subjected to pressure it tends to obey the laws of fluids, transmitting its pressure to all parts of its mass and flowing through an orifice through which it can escape, though it is far from being a perfect fluid. From this arises the modern conception of clay as a very viscous liquid in which every particle of solid matter is surrounded by a film of liquid, so that the particles are virtually in a state of suspension, and hence, that a plastic clay is, at any rate in part, in a colloidal condition. As far back as 1872 Schloesing* suggested that the plasticity of clay was due to its colloidal nature, and claimed to have found an amorphous material of the same composition as kaolin which had all the characteristics of a colloid, and was termed by him argile colloidale. Very little notice was taken of this suggestion or of the * This has more recently been confirmed by Cohn and Atterburg, who found that precipitated barium sulphate and calcium fluoride are both plastic when fresh. 129 allied work of other observers until 1896, when Rohland® investigated the subject further, and found indications that the colloidal nature of clay appeared likely to explain many of the facts noted in regard to plasticity. The nature of the colloid material apparently existing in many clays has already been described. In attempting to explain plasticity as being due to these colloids, it is assumed that some or all of the pores of the clay are filled with a colloidal solution (gel) obtained by the partial hydrolysis of the clay, and that the larger the proportion of pores so filled, the fatter and more plastic will be the clay, provided the proper ratio of granular material to colloid gel is retained. Rohland® and others have further shown that the addition of trifling amounts of electrolytes often produces great changes in the plasticity of a clay, and suggest that this characteristic of colloids is a strong argument in favour of the connection between the colloidal material in clay and plasticity. All electrolytes (such as acids) which yield hydrogen-ions on dissociation, increase the plasticity of clay, whilst those (such as alkalies) which yield hydroxyl-ions make a clay more fluid. Plasticity is not, however, entirely due to the presence of colloidal matter in clays, though the effect of colloids in increasing plasticity cannot, be denied. Hermann and others maintain that the presence of inorganic colloids in clay has never been conclusively proved. It should be noted that clay may be suspended in water and then precipitated or deflocculated indefinitely without impairing its plasticity. This is not usually the case with true mineral colloids, which usually set irreversibly and do not return to the colloidal condi- tion. Moreover, the whole of any individual clay grain is not softened upon the addition of water. Repeated wetting and pugging does not materially alter the size of the grains or change their general outline or appearance. This would not be the case if the clay were softened and reduced to a homogeneous mass, wetted, and subse- quently broken up with the formation of new grains when it was dried and ground. Whether wet or dry, under the microscope, the grains retain the appearance of a sharply-defined body. Another difficulty has been pointed out by J. M. van Bemmelen, viz., the rapidity with which colloids lose their power of absorbing water. This suggests that clays of great geological age cannot contain active colloids produced when the clay was formed, though they may contain colloidal substances derived from adventitious materials— organic or otherwise—at a comparatively recent period, The fact that many highly plastic clays appear to be free from such extraneous colloids only increases the difficulty regarding the latter as the cause of plasticity. Other objections of equal or greater weight may be urged against any single theory yet published on the causes of plasticity so that much further work requires to be done. Summarising the results of the numerous theories and experiments made, plasticity may be said to be due not to one, but to several causes, the chief of which are :— (i) The nature of the molecules of ‘“ true clay ” present. a 11454 I 130 (ii) The extremely small size of the particles, their lamellar shape, large surface (due to their porosity), and (possibly) their fissile character. In such small particles, the phenomena of cohesion are quite different from those in larger particles. (iii) The hydrolysing action of water on the particles and the probable production of inorganic colloid matter. If this is absent or neutralized by hydrogen-ions added purposely or occurring naturally or through fermentation of the organic matter in the clay, the plasticity will continue to increase until an excess of hydroxyl-ions is again produced; when the concentrations of hydroxyl-ions is large, the negatively charged clay particles will go into suspension. As the extent to which water can be dissociated is very limited, the plasticity of the clay can only be increased at so slow a rate that it is unlikely that slightly plastic clays (kaolin) can ever be made highly plastic by artificial means, though the increase in plasticity may be sufficient to show the nature of the reactions which take place. (iv) The presence of organic colloid matter due to impurities in the clay, or added purposely, may still further increase the plasticity. (v) The presence of minute quantities of soluble salts may exercise a pronounced effect on the plasticity. Their action has been mentioned under Viscosity (p. 121). Plasticity appears to be a resultant of several properties (see also Cohesion, Adsorption, Tensile Strength, Binding Power, &c.). To increase plasticity—The limits within which the plasticity of clay may be increased by the addition of soluble salts are very small, but there is such an abundance of naturally plastic clays that it is only where materials of exceptional purity are required that an increase in plasticity is desirable. A small increase in plasticity may be obtained :— (1) By increasing the hydrogen-ions in the material, by allowing the organic matter in the clay to decompose (ferment) and become acid, by adding weak acid, or by keeping the clay in intimate contact with fresh water by stirrmg the two together. ‘This appears to hydrolyse the clay and forms colloid matter on the particles. It is important to have the particles of clay ‘as small as possible in order to facilitate the hydrolysis. It ‘water alone is used for this purpose, the clay must be allowed to stand until fermentation of the organic matter begins, and the mass reacts faintly acid. In any case, the time required for an appreciable increase in the plasticity may be several years. No addition of any electrolytes or substance other than plastic clay can increase the true plasticity of a paste chiefly composed of non-plastic materials. Many of the so-called “ lean clays” are of this nature; they are rich in inert matter, but the proportion of colloidal matter in them is very small. Such clays can only be made more plastic by removing a large proportion of the inert matter naturally present in them or by 131 the addition of a highly plastic clay. The addition of electrolytes to such clays is only of value when their low plasticity is due to the clay gel present having become hardened or coagulated, but is still capable of being revived or deflocculated by means of an electrolytes or other simple treatment. (2) By keeping the clay in a moist damp cellar. This is termed “ ageing ”’ or “ souring.”’ (3) By the addition of colloids such as colloidal silica, alumina, or iron hydrate, hot starch, dextrin, tannin, rubber, sumach, inulin, caramel, gelatin, gum, glycogen, or various ferments and enzymes, the plasticity of the clay may be increased, but care must be taken to avoid confusion between true polasticity and the pseudo-plasticity caused by the addition of materials of an oily, gelatinous, or gummy nature. Some very interesting experiments. by Acheson and Ries on the effect of a 2 per cent. solution of tannin (gallotannic acid) on clay show that the addition of this substance notably increases the plasticity of clay, and at the same time apparently deflocculates it and breaks it up into finer particles. The tensile strength of the clay was nearly doubled. In a later patent, Acheson first adds tannin and alkalies or ammonia and stirs the clay into a fluid state, and then by the addition of a suitable quantity of acid he coagulates the colloids and forms a stiff paste. (4) By reducing a sufficient number of particles to so minute a state that they assume colloidal properties in the presence of.water. Thus, by very prolonged grinding with water many hard clays! become appreciably more plastic. The softer materials become exceedingly smooth and plastic ; the harder ones yield less readily to the treatment, but still develop marked pasticity, very similar to that of normal clay heavily overloaded with sand or grog. By selecting the materials and method of grinding, many degrees of plasticity may be obtained, from that of a very smooth plastic clay to that of a very short sandy clay, indicating that the difference is one of degree and not of kind, the essential characteristics being that the clay or other materials shall occur in a state of very fine subdivision, and that their surfaces are readily wetted by water. The chief practical difficulty lies in grinding sufficiently fine, as the smallest particle that can be seen under the microscope does not by any means represent the limit towards which the grinding should proceed. The plasticity produced by artificial grinding depends on the size and shape of the particles, and only indirectly on the materiak of which the plastic mass is formed. To reduce plasticity—(1) Hydroxyl-ions may be added and the temperature raised (direct reduction). (2) Non-plastic material may be added so as to spread the plasticity over a larger volume of material 1 Plastic material has been formed in this way from slate, plaster moulds, iron ore, ashes, lava, limestone, sandstone, burned brick, silica, mica, felspar, and even glass. I2 132 (indirect reduction or dilution). (3) The material may be heated to 200° C. or other suitable temperature. For the first method, any basic material, either organic or inorganic, may be used though lime water is the cheapest. If lime is too weak in hydroxyl-ions, caustic soda may be used, as may any salt composed of a strong base and a weak acid, such as sodium (or potassium) phosphates or silicates, all of which readily hydrolyse and yield hydroxyl-ions, though the cation constituent of the salt may exercise a considerable effect. Thus, borax reduces the influence of the hydroxyl-ions and potassium carbonate increases it, yet both are salts composed of a strong base and a weak acid. The concentration of the alkaline or basic material added is also of importance, and it may be necessary to render sulphates and other soluble salts insoluble by the addition of baryta, as suggested by Weber. Certain clays, as Weber has shown, act in precisely the reverse manner. These are free from sulphates, and appear to be rich in colloidal matter. Certain clays containing organic acids of a fatty nature are saponified on treatment with alkali, and the soap so produced increases, instead of diminishing, the plasticity, owing to the coagulation effected. The reduction of plasticity by raising the temperature considerably is described later. A comparatively small rise in temperature produced by the action of mechanical stirrers—will reduce the plasticity of clay if free hydroxyl-ions are present. The addition of non-plastic material, such as sand or grog, effects a reduction of the plasticity in an entirely different manner, by separating the clay particles from each other. It thus reduces the strength of the material, but by diminishing the shrinkage, it enables the clay to be used in a manner which would, otherwise, have been impossible, and the strength is seldom reduced sufficiently to make any notable difference to the user of the material. The proportion of non-plastic material to be added depends on the size of its grains and on the binding power of the clay. As the latter is closely connected with its plasticity, it will usually be found that the more plastic the clay, the larger the proportion of non-plastic material which may be used. Some sands are quite useless for this purpose, so that great care is needed in their selection. For some clays, chalk, flints, or grog is preferable to sand. The measurement of plasticity is a problem which has not yet been satisfactorily solved, probably for the reason that plasticity is the result of the united action of several forces some of which may not, as yet, have been recognised as important. Early attempts to measure plasticity usually resulted in only measuring one or more of these forces. Thus, Bischof added sand until the mixture was so soft that it could be rubbed away between his finger and thumb. Bischof’s figures are, however, a measure of the binding power of the clay, but not of its plasticity. Measurements of tensile strength, viscosity, the amount of water required to produce a mass of given consistency, the consistency, or the depth to which a Vicat needle will penetrate, Sokoloff’s slaking test and other single characteristics are all useful ia their way, but they fail to include all the properties involved in the 133 use of the term “ plasticity.’”’ Zschokke, who has examined the subject very fully, considers that the percentage of extensibility multiplied by the tensile strength of a freshly moulded clay cylinder of standard size (60 mm. high by 30 mm. diameter) is a coefficient of the plasticity. Modifications of this method have given excellent results in the hands of several experimenters in different countries and with a very large variety of clays. Grout considers that plasticity is proportional to the product of (a) the load required to sink a Vacat needle to a definite depth in a mass of clay; and (b) the deformation of the clay under stress, which he measures by the increase in area of a clay cylinder produced by a load which just causes eracks to appear. Both Zschokke and Grout?’ really consider plasticity to be measured by the product of the deformability and force resisting deformation, though they differ in the manner in which they measure these forces. More recently, Ashley? has adopted the same general idea as to the forces involved, but has assumed that the force-resisting deformation is exerted by the colloids in the clay. He, therefore, regards the plasticity of clay to be measured by the ratio :— Relative colloids x the shrinkage of the clay Jackson-Purdy surface factor. The term ‘relative colloids”? is explained in the section on Adsorption. As the ratio of the surface factor to shrinkage is approximately constant, Ashley concludes that the plasticity of the clay is directly proportional to the colloids present. The objection to this conclusion is that it appears unlikely, from other considerations, that the whole of the plasticity is due to the colloidal matter. Rohland’, also assuming that the colloidal matter in the clay is the chief factor of the plasticity, has suggested that the ratio obtained by dividing the coagulable colloids by the non-coagulable material is a measure of the plasticity. He ascertains it is by measuring the amount of water required to make the clay into the consistency of a good modelling paste, and argues that this is a-measure of the colloids because as soon as sufficient water is present to dissolve the coagulable colloids, a saturation point is reached and no more water can be absorbed without the clay iosing its stiffness. , Stormer has stated that plasticity may be judged by the following characteristics :— (1) The proportion of water (absorption) which must be added to the clay to make a good modelling paste. This is not always reliable. (2) The “ feel ’ of the paste when rubbed between. the finger and thumb (binding power). (3) The behaviour of the paste when rolled up into a ““ sausage ”” (toughness). (4) The adhesiveness of the clay (adhesion). (5) Twisting a piece of clay into a spiral and noting its behaviour (torsion). Metts a 134 (6) Noting the length of the threads, produced by expressing the clay from a vertical pug mill, before they break off by their own weight (tensile strength and extensibility). (7) Forming balls of clay and pressing them until the edges crack (crushing strength). (8) Bending cylinders of clay into a ring (bending moment). None of these characteristics taken alone can give a measure of the plasticity of a clay, though several of them are closely related to each other. The most reliable measure of plasticity appears to be that devised -by Zschokke (p. 133) or by Rosenow, who multiplies Zschokke’s figure by the percentage of water added to the dry clay to make it into a workable paste, 7.¢., by Rohland’s figure (p. 133). The binding power of a clay is the property it possesses of uniting with non-plastic material and water to form a uniform plastic paste, and is consequently closely related to the plasticity. This absorption of non-plastic material with the spread of plasticity throughout the whole mass has been attributed to the power of the saturated colloids (gels) to retain the non-colloidal particles in a state of pseudo-solution. Other colloids are known to possess ‘the property of preventing insoluble matter from settling, and this is, in some senses, a parallel case. The binding power of a clay may be determined by measuring the tensile strength of mixtures of clay with varying amounts of sand, but a skilled clayworker can tell by the “ feel” whether such mixtures are strong enough to be useful. In order to determine how much lean clay or non-plastic material can be added to a clay without unduly destroying its value for moulding into shape, Bischof’s test may be used. In this, the two materials are mixed in various proportions and the same measured quantity of water is added to each. The pastes are then rolled into small balls as equal in size as possible, and allowed to dry. They are then rubbed gently between the finger and thumb, or with a small “‘ camel hair”? brush. The mixture which just resists the action of rubbing may be taken as the standard. Some authorities make up balls of mixture in this way and then notice to what length a cylinder can be rolled from each without cracking. Clays with a high binding power are known technically as “ fat ” clays; ‘‘lean”’ clays are deficient in binding power. Some writers appear to consider that binding power and plasticity are synonymous; this is by no means the case, as a clay may be very plastic and yet not be able to bind much non-plastic material into a uniform plastic paste. At the same time, there is clearly some relationship between these two properties of clays. The dehydration of clays is accompanied by changes which are remarkably similar to those which occur in the dehydration of colloidal gels. The most important of these changes is the shrinkage or contraction of the mass, the production of a hard material which— if the dehydration is accomplished. by heat—may result in, the production of a material comparable to an irreversible gel. Plastic clays, like colloidal gels, shrink greatly when dehydrated and possess both a drying-shrinkage and a kiln-shrinkage. By mixing 135 an inert substance, such as sand, with a true colloid the shrinkage is lessened, and the cohesion of the dried colloid, including its adhesion to inert substances, are the causes of the increased mechanical strength of many such mixtures. This is another charac- teristic common to colloids and to all plastic clays. As there is no wholly reliable method of measuring plasticity (see p. 124), it is not possible to state precisely what relationship exists between the plasticity and the shrinkage of clays. Speaking broadly, the most plastic clays shrink more than those which are less plastic, but this is not invariably the case. For instance, the Lias clays usually shrink less than would be expected from their plasticity. When articles made of plastic clay are dried under suitable condi- tions, they contract equally in all directions, the contraction in volume being almost three times the linear shrinkage. Excessively plastic clays erack, or twist, when dried and many moderately plastic clays will do so if dried irregularly or too rapidly. When water is added to a dry clay, it is first absorbed by the pores, but, when these are filled, any further supply of water appears to cause a separation of the particles from each other so that the volume of clay is increased, though not in proportion to the water added. The amount of water which can be absorbed in this manner differs greatly with different clays. The stage at which the clay contains the maximum quantity of water without loss of shape is also the point of maximum plasticity; it is said to be the “ point of saturation of the coagulated colloids (gels) in the clay.’ If some of this water is removed, the volume of the mass begins to diminish and contraction occurs. This contraction or shrinkage is chiefly, but not entirely, due to the removal of water from the clay by evaporation at the ordinary temperature (air-shrinkage), at a somewhat higher tempera- ture in the dryer (dryer-shrinkage), or during the burning (kiln- shrinkage). As all coagulated colloids (gels) which are saturated with water shrink when the water is removed, some investigators consider that the shrinkage of clay may be due in part to this cause. The more general idea (which states facts rather than explains them) is that, as the water is removed, any whith remains draws the clay particles together into a smaller and denser mass. The amount of shrinkage appears to depend partly upon the rate ‘at which the clay is dried, for if this operation is performed rapidly the shrinkage will be less, the clay particles not having time to move over each other so freely as when the drying is slower. When drying a strong, porous clay, the water first evaporates from the surface and is replaced by capillary action from the interior, the mass contracting by the same amount as the water diminishes. All the pores remain filled with water until the rate of evaporation exceeds the rate at which the pores will transmit water. This point occurs, when the clay particles move so much less freely on each other that the rate of evaporation exceeds that of the contraction. After the first stage of surface-drying, the exterior loses water more rapidly than the interior; in the second stage the pores are no longer filled with 136 water at their outer ends and begin to form spaces in the clay, these spaces being filled with air and water vapour. Contraction still occurs throughout this second stage until the substance is so far solidified that the individual particles can no longer slip over each other at all. The third stage is then reached in which capillary action and shrinkage cease entirely. Evaporation now takes place entirely within the mass, and spaces are formed exactly corresponding to the water lost. That shrinkage ceases before the clay is completely deprived of water is shown by Aron and Brogniart to be characteristic of many, but not of all, clays. Aron supposed that the clay shrinks until the particles are practically in contact with each other, so that any further water which may be driven off does not make any notable difference in the volume of the clay; but supporters of the colloid theory argue that the heat used in drying really cause the colloid particles to shrivel, thus reducing their surface and increasing their density. Aron has further shown that the “ pore space”’ is constant for each kind of clay,:and is independent of the amount of water of formation added to the clay, though this last statement is only true of the purer clays. If, now, the pastes made with varying amounts of water of formation are subjected to exactly the same conditions of drying, the rate is not proportional to the water added, but is slower in proportion for those with less water. It takes, approximately, the proportional time in the first two stages of drying, but the more solid the mass the longer it takes to eliminate the last portions of the water. It follows also from this, that want of uniformity in the substance of a mass of clay, such as must exist in bricks made by hand, and in a less degree in those made in a press or die, causes a corresponding want of uniformity in the shrinkage and the rate of drying in different parts of it. This is one cause of the warping or twisting of bricks in drying. In the second stage of drying, all clays lose water more rapidly on the outside than on the inside, the angles and arrises in their turn drying more rapidly than the faces. The consequence of the greater shrinkage of the outer layer is a frequent cause of cracking, and it is, therefore, necessary to pursue this stage with great caution and to effect the drying with air already heavily charged with moisture. It is also essential, for this reason, to avoid the excessive prominence of any part of a complex-shaped article, and it is advisable to follow any projections on the exterior with hollows on the interior, so as to maintain an approximately regular thickness of material throughout. The frogs or indents on both sides of a common brick are serviceable in drying for the same reason. In a re-pressed brick, they serve the additional purpose of rendering the consistency more even throughout. For objects of reasonable size, the rate of drying is approximately proportional to the ratio of surface to volume. Objects of large size, however, take much longer to dry, and require the application of considerable heat to complete the removal of all the water of manu- facture from the interior. Many large goods made of fireclay and stoneware clay require extremely careful treatment, and have to be kept in a heated atmosphere for several days after the moisture 137 has apparently been completely removed. Disastrous results have frequently been known to occur in the steaming operations in the kiln for want of sufficient care in this particular. Manufacturers frequently adopt a very wise precaution in having such goods stamped with the date of making, and in holding their workmen responsible if they are rendered unsound by being burned before the lapse of a stated period of drying. In order that the goods may not twist or warp when drying, it is essential that they should shrink very little. This means that only a limited proportion of plastic clay can be used in the material, although some is necessary to bind the particles together and to give it the general characteristics of “clay.” With a carefully compounded mixture, the contraction of the paste prior to entering the kiln should not exceed 1 inch in 16 (or ? inch per foot). If it does so, more non-plastic material must be added. The lower the contraction, the better the chance of the ware coming “ true” out of the drying rooms; hence, as much non-shrinking material as possible should be used in the clay mixtures, so as to keep the contrac- tion at a minimum. The addition of a non-plastic material to a clay enables less water of formation to be used, and so reduces the shrinkage, but Aron has shown that if the amount of water is kept the same as for the clay alone, the addition of non-plastic material will increase the contraction which occurs on drying, until a certain point (that of maximum density) is reached. After this, the more “grog” added to the clay the less will it shrink, and the greater will be the porosity. The nature of the non-plastic material added will also affect the shrinkage to some extent, and will exercise a considerable influence on the amount of water which must be mixed with the clay. Thus, a porous, burned clay will absorb more water than will sand. Provided the non-plastic material is of a nature suitable to the clay (this must be determined by actual experiment), it may be added in any desired proportion so long as it does not too seriously reduce the strength of the mass, as it will do if more is added than the binding power of the clay can accommodate. The porosity of a dehydrated clay appears to be due to the capillary structure of the material. Other properties which clays in the plastic state possess in common with colloids are :— Unctuousness, or a smooth, almost greasy, “ feel,” is a characteristic of some clays, a few being so oleaginous that they may be saponified by treatment with caustic alkali, the plasticity being thereby increased. In most cases, however, such treatment makes the clay more fluid. Toughness, or cohesion, is closely allied with (1) extensibility, or the ability of clay to stretch when pulled, which is measured by ascertaining the fullest extent to which a clay test-piece of a given size will stretch without breaking; (2) torsion, or the extent to which a piece of clay can be twisted, which is measured by. clamping one end of a bar of clay as rigidly as possible and rotating the other slowly by means of a screw, counting the number of complete revolutions which can be made before the bar breaks; (3) bending moment, or 1338 the angle through which a bar of clay can be bent without rupture; (4) elasticity, or the extent to which a piece of clay can be stretched and yet return to its original length when the tension is removed. Many plastic clays show slight elasticity, though it is usually too small to be measurable. The tensile strength of a clay is its resistance to torsion or to being pulled apart. The non-plastic materials influence its strength inversely as the diameter of their grains, so that fine-grained clays will usually be the strongest, though an excess of very fine or very coarse grains will cause the clay to break prematurely. In support of the theory that the grains of clay interlock to some extent, Ries found that mixtures of two clays can be made which have a higher tensile strength than either clay taken separately. This fact has long been known by the makers of crucibles for steel-melting in this country, as many as four different clays being sometimes used to produce a sufficiently strong crucible. The tensile strength of the clay has, in fact, an important bearing on its resistance to accidents in the process of manufacture, particularly from the commencement of drying to that of firing. It has sometimes been stated that the tensile strength of a clay enables it to carry a large quantity of non-plastic material, but this is rather confusing the effect with the cause. It is the binding power of the clay which enables it to carry such a large quantity of added material and still retain a sufficiently high tensile strength. Olschewsky has proved that there is no direct relationship between the binding power of a clay and its tensile strength when dry. It was at one time thought that the tensile strength of clays is proportional to the plasticity, but this is only true, if at all, when the pieces are tested in the moist (plastic) state. If air-dried, the definite relationship ceases. The tensile strength of dried raw clays depends on the proportions of the grains of different sizes. Equal-sized grains cannot be packed into a dense mass. An excessive proportion of the finest clay particles or a large percentage of sand grains (0-5-1:Omm.) weakens the strength of an air-dried clay. Fissility—or capability of being split up into thin slabs or flat pieces, or even into flakes or foliations—is characteristic of many indurated clays, especially of shales. If the splitting can be effected sc as to form plates of extreme thinness, the material is said to be laminated; if the tendency to split_is strongest in the direction of bedding, the material is termed shaley; if this tendency is strongly marked in any other direction it is said to be fissile, as are slates and certain limestones and sandstones. Sectility, or capability of being easily cut, is a characteristic of clays which occur in a plastic condition, such as ball clays and many surface clays. This property often serves as a means of distinguishing “clays ” from other minerals, though the “ clays”? so found may be too impure to be of any commercial value. Anyone constantly engaged in examining clays soon learns to recognise some varieties by their sectility and by the slightly glossy appearance of the freshly- cut surfaces, though these cannot be clearly described. 139 The effects of age on a clay paste are similar to those on colloidal gels, provided the conditions of storage (including the low temperature and a sufficiently humid atmosphere) are favourable. The plasticity of the clay is slightly increased and the colloidal properties are more marked. From the foregoing, there appears to be a close parallelism between the more important properties of plastic clays and those of other colloids, but the question still remains as to whether these colloidal properties are due to the nature of an essential constituent of clays (clay substance) or to other colloidal substances which may be present. Other Colloids in Clay. The most important colloidal substances which are known definitely to exist in some clays are :— Colloidal silica, which may exist in the form of a silica hydrogel, with or without occluded silica hydrosol, the latter being confined to any liquid portions of the clay paste, but distributed more or less uniformly throughout the clay slip. Various mineral forms of silica which are hydrogels are known; they possess the anticipated properties of inorganic gels and their nature is fairly well known. A small percentage of colloidal silica may be extracted by boiling some clays with water, with or without the addition of a little sodium carbonate, but in no clay of commercial importance is the amount of silica obtainable so large as to account for the whole of the _ plasticity of such clays, though it may partly do so. Wolfgang Ostwald” holds the view that silicic acid sols are hydrated emulsoids, i.e., the dispersed silicic acid is a liquid and not a solid. Like other known emulsoids, its viscosity is high and rises very rapidly after a given concentration whilst in suspensoid sols the increase of viscosity is steady throughout and the viscosity is very low. He also states that the silicic acid gel differs from the better known organic emulsoids in possessing little elasticity. Attempts to increase the plasticity of sand by mixing it with silica _hydrosol, and coagulating the latter, do not produce a material at all closely resembling plastic clay. Such a mixture, when dry, is _ deficient in strength and even in its most plastic state it is inferior _to clay for modelling purposes.